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Varsani, Arvind; Villiers, Gillian K.; Regnard, Guy L.; Bragg, Robert R.; Kondiah, Kulsum; Hitzeroth, Inga I.; Rybicki, Edward P.
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Beak and feather disease virus (BFDV), the causative agent of psittacine beak and feather disease (PBFD) infects psittaciformes worldwide. We provide an annotated sequence record of three full-length unique genomes of BFDV isolates from budgerigars (Melopsittacus undulatus) from a breeding farm in South Africa. The isolates share >99% nucleotide sequence identity with each other and ~96% nucleotide sequence identity to two recent isolates (Melopsittacus undulatus) from Thailand but only between 91.6 and 86.6% identity with all other full-length BFDV sequences. Maximum-likelihood analysis and recombination analysis suggest that the South African budgerigar BFDV isolates are unique to budgerigars, are non-recombinant in origin, and represent a new genotype of BFDV.
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Lourens, Chris; Watkins, William M; Barnes, Karen I; Sibley, Carol H; Guerin, Philippe J; White, Nicholas J; Lindegardh, Niklas
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The Worldwide Antimalarial Resistance Network (WWARN) is a global collaboration to support the objective that anyone affected by malaria receives effective and safe drug treatment. The Pharmacology module aims to inform optimal anti-malarial drug selection. There is an urgent need to define the drug exposure - effect relationship for most anti-malarial drugs. Few anti-malarials have had their therapeutic blood concentration levels defined. One of the main challenges in assessing safety and efficacy data in relation to drug concentrations is the comparability of data generated from different laboratories. To explain differences in anti-malarial pharmacokinetics in studies with different measurement laboratories it is necessary to confirm the accuracy of the assay methods. This requires the establishment of an external quality assurance process to assure results that can be compared. This paper describes this process.
The pharmacology module of WWARN has established a quality assurance/quality control (QA/QC) programme consisting of two separate components:
1. A proficiency testing programme where blank human plasma spiked with certified reference material (CRM) in different concentrations is sent out to participating bioanalytical laboratories.
2. A certified reference standard programme where accurately weighed amounts of certified anti-malarial reference standards, metabolites, and internal standards are sent to participating bioanalytical and in vitro laboratories.
The proficiency testing programme is designed as a cooperative effort to help participating laboratories assess their ability to carry out drug analysis, resolve any potential problem areas and to improve their results - and, in so doing, to improve the quality of anti-malarial pharmacokinetic data published and shared with WWARN.
By utilizing the same source of standards for all laboratories, it is possible to minimize bias arising from poor quality reference standards. By providing anti-malarial drug standards from a central point, it is possible to lower the cost of these standards.
Brown, Judith K.; Zerbini, F. Murilo; Navas-Castillo, Jesús; Moriones, Enrique; Ramos-Sobrinho, Roberto; Silva, José C. F.; Fiallo-Olivé, Elvira; Briddon, Rob W.; Hernández-Zepeda, Cecilia; Idris, Ali; Malathi, V. G.; Martin, Darren P.; Rivera-Bustamante, Rafael; Ueda, Shigenori; Varsani, Arvind
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Viruses of the genus Begomovirus (family Geminiviridae) are emergent pathogens of crops throughout the tropical and subtropical regions of the world. By virtue of having a small DNA genome that is easily cloned, and due to the recent innovations in cloning and low-cost sequencing, there has been a dramatic increase in the number of available begomovirus genome sequences. Even so, most of the available sequences have been obtained from cultivated plants and are likely a small and phylogenetically unrepresentative sample of begomovirus diversity, a factor constraining taxonomic decisions such as the establishment of operationally useful species demarcation criteria. In addition, problems in assigning new viruses to established species have highlighted shortcomings in the previously recommended mechanism of species demarcation. Based on the analysis of 3,123 full-length begomovirus genome (or DNA-A component) sequences available in public databases as of December 2012, a set of revised guidelines for the classification and nomenclature of begomoviruses are proposed. The guidelines primarily consider a) genus-level biological characteristics and b) results obtained using a standardized classification tool, Sequence Demarcation Tool, which performs pairwise sequence alignments and identity calculations. These guidelines are consistent with the recently published recommendations for the genera Mastrevirus and Curtovirus of the family Geminiviridae. Genome-wide pairwise identities of 91 % and 94 % are proposed as the demarcation threshold for begomoviruses belonging to different species and strains, respectively. Procedures and guidelines are outlined for resolving conflicts that may arise when assigning species and strains to categories wherever the pairwise identity falls on or very near the demarcation threshold value.
Faure, Jacqueline; Uys, Joachim D. K.; Marais, Lelanie; Stein, Dan J.; Daniels, Willie M. U.
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Early adverse life events, followed by subsequent stressors, appear to increase susceptibility for subsequent onset of psychiatric disorders in humans. The molecular mechanisms that underlie this phenomenon remain unclear, but dysregulation of the HPA axis and alterations in neurotrophic factors have been implicated. The present study investigated the effects in rodents of early maternal separation, followed by stress in adolescence and adulthood on later HPA-axis activity and hippocampal neurotrophin levels (brain-derived neurotrophic factor, nerve growth factor, and neurotrophin-3). Animals subjected to repeated stressors showed a significant decrease in basal ACTH (p < 0.05) and CORT (p < 0.05) levels when compared to controls, as well as significantly increased levels of NGF in the dorsal (p < 0.001) and ventral hippocampus (p < 0.01), and of NT-3 in the dorsal hippocampus (p < 0.01). Dysregulation of the HPA axis after multiple stressors is consistent with previous preclinical and clinical work. Given that neurotrophins are important in neuronal survival and plasticity, it is possible to speculate that their elevation reflects a compensatory mechanism.
Folb, Peter I.
Over the past 10–15 years, society has become increasingly preoccupied with the safety of medicines. This reaction, commonly attributed simply to "thalidomide", reflects in fact a more widespread concern with the rights and protection of the consumer in every field and with ecology and the preservation of the environment. In the development of new medicines today the pharmaceutical industry spends vast amounts of time and money on the evaluation of safety before a human being is exposed to them. Furthermore, the demands of the public and of regulatory authorities, together with the stringent requirements for safety of industry and physicians alike, have tended to make efforts for the assurance of safety of a new medicine ever more rigorous.
Pettit, George R.; Cragg, Gordon M.
Scott, Chantelle Jennifer; Futter, Merle; Wonkam, Ambroise
This study aims to evaluate the attitudes of a group of South African parents with a preschool child with Down syndrome (DS) towards prenatal diagnosis (PND) and termination of a Down syndrome-affected pregnancy (TAP). This study employs a qualitative phenomenological approach with the use of semi-structured interviews. Twelve participants were recruited from two state sector hospitals in Cape Town, South Africa. Thematic analysis was used to interpret the data. The participants had a positive attitude towards PND and felt that it was every parent's right to have the option. They considered a benefit of PND the fact that it allowed parents time to prepare for the arrival of a baby with DS. The induced miscarriage risk associated with invasive prenatal testing procedures caused major negative feelings. They were totally opposed to the termination of a Down syndrome-affected pregnancy due to their personal experience, moral, ethical or religious convictions. South African parents of preschool children with Down syndrome are comfortable with PND for Down syndrome; however, they do not support TAP. These findings will provide health care providers with further insight into the motivations behind the decisions their patients make.
Noakes, Timothy D.; Nolte, Heinrich W.
Ridgway, T. M.; Branch, G. M.; Stewart, B. A.; Hodgson, A. N.
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The species boundaries between members of the southern African 'Patella miniata' species complex (Patella miniata miniata, P. miniata sanguinans and P. compressa) are poorly defined on morphological grounds. Doubt also exists whether all populations of P. miniata miniata constitute a single taxon, with 'P. cf. miniata' having uncertain affinities. The status of P. adansonii (known only from shells) is also obscure. Protein gel electrophoresis was employed to resolve these taxonomic uncertainties. In addition, a population of P. safiana from southern Angola was included in the study as a reference population. Electrophoretic analysis of 16 enzyme loci revealed four distinctive groupings. All populations of P. miniata miniata and P. cf. miniata proved closely related and separated from P. compressa populations at I=0.85; the P. miniata sanguinans populations clustered out at I=0.79; and P. safiana separated at I=0.69. Phylogenetic analyses, using P. safiana as an outgroup, indicated that P. miniata miniata, P. miniata sanguinans and P. compressa form a closely related monophyletic group in which P. miniata miniata and P. compressa are more closely related to each other than either one of them is to P. miniata sanguinans. Morphological analyses (shells, radula, sperm microstructure) revealed differences that mirrored the differences detected by the allozymes. Thus, it was concluded that P. miniata sanguinans and P. miniata miniata warrant full specific status and we therefore raise the former to P. sanguinans. Patella miniata miniata and P. cf. miniata are geographic variants of the same species, P. miniata, and P. adansonii is sunk within this species. Furthermore, the suggestion that P. miniata and P. compressa may be ecomorphs of the same species are not supported and both warrant specific status. Thus, the 'Patella miniata' species complex in southern Africa is a closely related monophyletic group of three species, with P. miniata and P. compressa being more closely related to each other than either one is to P. sanguinans.
Passmore, Jo-Ann S; Morroni, Chelsea; Shapiro, Samual; Williamson, Anna-Lise; Hoffman, Margaret
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In a case-control study among 2064 South African women to investigate the risk of clinically invasive cancer of the cervix, we found a marked reduction in the risk of cervical cancer among women who gave a history of ever having undergone even a single Pap smear, and a statistically significant decline in the HPV positivity rate correlated with the lifetime number of Pap smears received. HPV infections and their associated low-grade lesions commonly regress, indicating that most often there is an effective host immune response against HPV infection. We hypothesized that act of performing a Pap smear is associated with inflammatory responses at the site of trauma, the cervix, and that this inflammatory signalling may be an immunological factor initiating these productive anti-HPV responses. In the present study, a randomized controlled trial, we enrolled 80 healthy young women to investigate the impact of performing a Pap smear on cervical inflammation. Forty one women, in the intervention group, received a Pap smear at enrollment and cervicovaginal lavages (CVLs) were collected at baseline and 2 weeks later. Thirty nine women received no intervention at enrollment (control group) but CVLs were collected at enrolment and 2 weeks later. We assessed various markers of inflammation including IL-12 p70, TNF-α, IL-8, IL-6, IL-10, and IL-1β in CVL specimens. While CVL levels of IL-8, IL-1β and IL-6 remained unchanged following a Pap smear, markers of cell mediated immunity (IL-12 p70 and TNF-α) and T cell regulation (IL-10) were significantly elevated.
Labuschagné, Antoinette; Jacobs, Muazzam
Tuberculosis (TB) and human immunodeficiency virus (HIV) have been closely linked since the emergence of acquired immune deficiency syndrome (AIDS), to date the main focus of research has been on studying the diseases separately. The epidemiology, clinical manifestations, and management of both HIV and Mycobacterium tuberculosis (M.tb) infections are different and far more involved in coinfected compared to monoinfected individuals. There are complex interacting forces driving pathogenesis of each disease, and our understanding of these mechanisms remains inadequate to best develop preventive measures against the "dual disease." Deficiencies in our knowledge mainly stem from the lack of a standardized animal model for studying the synergy between bona fide HIV and M.tb. Although conventional mouse models have improved our understanding of TB outside of the context of HIV, wild-type mice are not amendable for HIV/TB coinfection research. Improvements in the humanized mouse model are allowing HIV-1 and TB copathogenesis studies. Here, we discuss the possibilities for TB/HIV-1 coinfection in humanized mice and the limitations and suggestions on improving the humanized mouse model specifically for TB/HIV-1 coinfection studies.
Cunningham, J.; Baard, E.H.W.; Harley, E.H.; O'Ryan, C.
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Microsatellite DNA was used to investigatelevels of genetic variability in severelyfragmented populations of the geometrictortoise, Psammobates geometricus, themost endangered tortoise on mainland Africa.Eight microsatellite markers were used toassess genetic variability within and betweenthree naturally occurring populations of P. geometricus. These populations areseparated by the Cape Fold mountain ranges inthe western Cape region of South Africa. Levels of variability were quantified usingallelic diversity, genotypic frequencies andheterozygosity. Evidence for populationsub-structuring was examined using Fstatistics, Rst and δμ2.High levels of variability were found in allthree populations. Low levels of populationdifferentiation were found suggestingsignificant gene flow between the populations.
Sloan, A. W.
The Harvard step test (modified for women) and a modified AAHPER test battery were performed by 144 White and Coloured student teachers, of whom 45 were students of physical education (PE). The rapid fitness index (RFI) was calculated for the Harvard step test and a composite criterion of fitness was derived from the results of the seven tests which comprise the AAHPER test battery.
For men and for women there was a highly significant correlation between the two estimates of physical fitness (RFI and AAHPER criterion) and a good correlation between the criterion and each of the individual AAHPER tests, the highest being with the standing broad jump. The correlation between RFI and individual AAHPER tests was poor in men but good in women. In both sexes the highest correlation was with the 600-yard run.
In general, both men and women PE students were fitter than their controls but there was no consistent difference between White and Coloured students in the results of the fitness tests although the White men and women were taller and heavier. The observed differences are probably not due to race but to different degrees of physical activity.
Gregorowski, Claire; Lochner, Christine; Martin, Lindi; Simmons, Candice; Kidd, Martin; Walker, Kathleen; Wilmshurst, Jo M.; Seedat, Soraya
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This was an exploratory study comparing neuropsychological manifestations of Sydenham's chorea (SC), 6 months after initiation of treatment, in children who had received intravenous immunoglobulins as an adjunct to standard treatment, with those who had received standard treatment. We included a non-SC control group for comparison. We hypothesized that compared to controls, children with SC who had received prior intravenous immunoglobulins would demonstrate less pronounced impairments compared to those who had received standard care. We conducted a cross-sectional analysis of 17 children with −SC who had received treatment 6 months previously (9 treated with standard of care and 8 augmented with intravenous immunoglobulins) and 17 non-SC, medically well controls. The standard treatment group (n = 9) exhibited significant behavioral difficulties, including significantly poorer co-operation (p = 0.009) compared with the other augmented immunoglobulins and non-SC control groups, and increased impulsivity (p = 0.016) compared with non-SC controls. The standard treatment group scored significantly lower than the other two groups on a measure of executive functioning (p = 0.03). Children with SC may be more at risk for neuropsychological difficulties than non-SC, medically well children. Intravenous immunoglobulins may mitigate some of these impairments.
Becker, John VW; van der Merwe, Marina M; van Brummelen, Anna C; Pillay, Pamisha; Crampton, Bridget G; Mmutlane, Edwin M; Parkinson, Chris; van Heerden, Fanie R; Crouch, Neil R; Smith, Peter J; Mancama, Dalu T; Maharaj, Vinesh J
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Anti-malarial drug resistance threatens to undermine efforts to eliminate this deadly disease. The resulting omnipresent requirement for drugs with novel modes of action prompted a national consortium initiative to discover new anti-plasmodial agents from South African medicinal plants. One of the plants selected for investigation was Dicoma anomala subsp. gerrardii, based on its ethnomedicinal profile.
Standard phytochemical analysis techniques, including solvent-solvent extraction, thin-layer- and column chromatography, were used to isolate the main active constituent of Dicoma anomala subsp. gerrardii. The crystallized pure compound was identified using nuclear magnetic resonance spectroscopy, mass spectrometry and X-ray crystallography. The compound was tested in vitro on Plasmodium falciparum cultures using the parasite lactate dehydrogenase (pLDH) assay and was found to have anti-malarial activity. To determine the functional groups responsible for the activity, a small collection of synthetic analogues was generated - the aim being to vary features proposed as likely to be related to the anti-malarial activity and to quantify the effect of the modifications in vitro using the pLDH assay. The effects of the pure compound on the P. falciparum transcriptome were subsequently investigated by treating ring-stage parasites (alongside untreated controls), followed by oligonucleotide microarray- and data analysis.
The main active constituent was identified as dehydrobrachylaenolide, a eudesmanolide-type sesquiterpene lactone. The compound demonstrated an in vitro IC50 of 1.865 μM against a chloroquine-sensitive strain (D10) of P. falciparum. Synthetic analogues of the compound confirmed an absolute requirement that the α-methylene lactone be present in the eudesmanolide before significant anti-malarial activity was observed. This feature is absent in the artemisinins and suggests a different mode of action. Microarray data analysis identified 572 unique genes that were differentially expressed as a result of the treatment and gene ontology analysis identified various biological processes and molecular functions that were significantly affected. Comparison of the dehydrobrachylaenolide treatment transcriptional dataset with a published artesunate (also a sesquiterpene lactone) dataset revealed little overlap. These results strengthen the notion that the isolated compound and the artemisinins have differentiated modes of action.
The novel mode of action of dehydrobrachylaenolide, detected during these studies, will play an ongoing role in advancing anti-plasmodial drug discovery efforts.
van der Walt, Eric; Palmer, Kenneth E; Martin, Darren P; Rybicki, Edward P
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A variety of interactions between up to three different movement proteins (MPs), the coat protein (CP) and genomic DNA mediate the inter- and intra-cellular movement of geminiviruses in the genus Begomovirus. Although movement of viruses in the genus Mastrevirus is less well characterized, direct interactions between a single MP and the CP of these viruses is also clearly involved in both intra- and intercellular trafficking of virus genomic DNA. However, it is currently unknown how specific these MP-CP interactions are, nor how disruption of these interactions might impact on virus viability.
Using chimaeric genomes of two strains of Maize streak virus (MSV) we adopted a genetic approach to investigate the gross biological effects of interfering with interactions between virus MP and CP homologues derived from genetically distinct MSV isolates. MP and CP genes were reciprocally exchanged, individually and in pairs, between maize (MSV-Kom)- and Setaria sp. (MSV-Set)-adapted isolates sharing 78% genome-wide sequence identity. All chimaeras were infectious in Zea mays c.v. Jubilee and were characterized in terms of symptomatology and infection efficiency. Compared with their parental viruses, all the chimaeras were attenuated in symptom severity, infection efficiency, and the rate at which symptoms appeared. The exchange of individual MP and CP genes resulted in lower infection efficiency and reduced symptom severity in comparison with exchanges of matched MP-CP pairs.
Specific interactions between the mastrevirus MP and CP genes themselves and/or their expression products are important determinants of infection efficiency, rate of symptom development and symptom severity.
Marais, Lelanie; Hattingh, Suzél M.; Stein, Dan J.; Daniels, Willie M. U.
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Early life stress is known to predispose humans to the development of depression. Developmental stress has been shown to cause various changes in neurotransmitter systems, neurotrophin expression and the hypothalamic pituitary adrenal-axis in the rat brain. The aim of this study was to identify which cytosolic proteins are altered by maternal separation, as a model for depression, as well as by chronic antidepressant treatment. Rats were maternally separated from postnatal day 2–14 for 3 h per day while control rats were normally reared. Both groups were divided and received either escitalopram or saline injections for 6 weeks starting from postnatal day 40. The ventral hippocampal tissue was fractionated and the cytosolic fraction used for 2-D-gel electrophoresis and liquid chromatography coupled to mass spectrometry analyses to identify peptides. Mascot database searches were done to identify proteins that were differentially expressed between the groups. Proteins that were significantly changed by maternal separation included amongst others: molecular chaperones and proteins related to energy metabolism; neuroplasticity; oxidative stress regulation; and protein metabolism. Treatment with escitalopram, a selective-serotonin reuptake inhibitor, induced changes in a different group of proteins, except for a few involved in energy metabolism and neuroprotective pathways. The results indicate which cytosolic proteins are changed by early life stress and may therefore be involved in the development of depression.
Rensburg, Susan J.; Carstens, Machteld E.; Potocnik, Felix C. V.; Aucamp, Abraham K.; Taljaard, Joshua J. F.; Koch, Klaus R.
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The membrane fluidity of platelet and erythrocyte membranes in 10 Alzheimer's disease patients and 9 age-matched controls was studied. The platelet membranes of patients with Alzheimer's disease were found to be significantly more fluid than those of controls (p<0.02). However, erythrocyte membranes of Alzheimer patients were less fluid (more viscous) than those of controls (p<0.05). On further investigation of platelet and erythrocyte membranes obtained from healthy volunteers, the fluidity was found to change with increasing aluminium concentrations. When aluminium ammonium sulphate (0.01–10 μM) was added to membrane suspensions, the fluidity of platelet membranes was increased, whereas the fluidity of erythrocyte membranes was decreased (i.e. the microviscosity was increased).
Howells, Fleur M; Bindewald, Leander; Russell, Vivienne A
Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable developmental disorder resulting from complex gene-gene and gene-environment interactions. The most widely used animal model, the spontaneously hypertensive rat (SHR), displays the major symptoms of ADHD (deficits in attention, impulsivity and hyperactivity) and has a disturbance in the noradrenergic system when compared to control Wistar-Kyoto rats (WKY). The aim of the present study was to determine whether the ADHD-like characteristics of SHR were purely genetically determined or dependent on the gene-environment interaction provided by the SHR dam.
SHR/NCrl (Charles River, USA), WKY/NCrl (Charles River, USA) and Sprague Dawley rats (SD/Hsd, Harlan, UK) were bred at the University of Cape Town. Rat pups were cross-fostered on postnatal day 2 (PND 2). Control rats remained with their birth mothers to serve as a reference for their particular strain phenotype. Behavior in the open-field and the elevated-plus maze was assessed between PND 29 and 33. Two days later, rats were decapitated and glutamate-stimulated release of [3H]norepinephrine was determined in prefrontal cortex and hippocampal slices.
There was no significant effect of "strain of dam" but there was a significant effect of "pup strain" on all parameters investigated. SHR pups travelled a greater distance in the open field, spent a longer period of time in the inner zone and entered the inner zone of the open-field more frequently than SD or WKY. SD were more active than WKY in the open-field. WKY took longer to enter the inner zone than SHR or SD. In the elevated-plus maze, SHR spent less time in the closed arms, more time in the open arms and entered the open arms more frequently than SD or WKY. There was no difference between WKY and SD behavior in the elevated-plus maze. SHR released significantly more [3H]norepinephrine in response to glutamate than SD or WKY in both hippocampus and prefrontal cortex while SD prefrontal cortex released more [3H]norepinephrine than WKY. SHR were resilient, cross-fostering did not reduce their ADHD-like behavior or change their neurochemistry. Cross-fostering of SD pups onto SHR or WKY dams increased their exploratory behavior without altering their anxiety-like behavior.
The ADHD-like behavior of SHR and their neurochemistry is genetically determined and not dependent on nurturing by SHR dams. The similarity between WKY and SD supports the continued use of WKY as a control for SHR and suggests that SD may be a useful additional reference strain for SHR. The fact that SD behaved similarly to WKY in the elevated-plus maze argues against the use of WKY as a model for anxiety-like disorders.
Lehohla, Molupe; Russell, Vivienne Ann; Kellaway, Lauriston
Exposure to an enriched environment provides animals with informal learning opportunities and is associated with increases in brain size, cortical thickness, neuron size, dendritic branching, spine density, and number of synapses per neuron. The NMDA receptor is involved in synaptic plasticity. This study sought to determine the effect of exposure to an enriched environment on NMDA receptor function in barrel cortex slices of spontaneously hypertensive rats (SHR) and their control Wistar-Kyoto (WKY) rats. An assortment of items such as PVC pipes, metal pipes, metal boxes, metal ladders, and a polystyrene maze, were placed successively in the cages of test animals to create an enriched environment. After 2 weeks, the rats were killed. Their brains were rapidly removed, cooled in continuously oxygenated HEPES buffer (pH 7.4), and sliced in a vibratome to produce 0.35-mm thick slices. The barrel cortex was dissected from slices corresponding to 8.6–4.8 mm anterior to the interaural line and incubated with 45Ca2+ and 100 μM NMDA for 2 min. There was no difference between rats exposed to an enriched environment and rats kept in standard cages. Enrichment of environment did not alter NMDA-stimulated Ca2+ uptake into barrel cortex of SHR and WKY.
Olivier, AJ; Roberts, L; Coetzee, D; Williamson, A; Passmore, JS; Burgers, WA
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Martin, Darren P.; Briddon, Rob W.; Varsani, Arvind
Recombination has profoundly shaped the evolution of viruses in the family Geminiviridae and has been studied extensively in the two best characterised geminivirus lineages: the dicotyledonous plant infecting begomoviruses and the monocotyledonous plant infecting mastreviruses. Here, we demonstrate that the sizes and distributions of recombination events detectable within the members of a third major geminivirus lineage—the dicotyledonous plant infecting mastreviruses—are very similar to those of the monocot-infecting mastreviruses. This suggests that, despite host range differences, very similar biochemical, ecological and evolutionary factors must underlie recombination patterns in the dicot- and monocot-infecting mastreviruses.
Kwiatkowski, Maja A.; Roos, Annerine; Stein, Dan J.; Thomas, Kevin G. F.; Donald, Kirsty
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Prenatal methamphetamine exposure (PME) is a significant problem in several parts of the world and poses important health risks for the developing fetus. Research on the short- and long-term outcomes of PME is scarce, however. Here, we summarize present knowledge on the cognitive and behavioral outcomes of PME, based on a review of the neuroimaging, neuropsychology, and neuroscience literature published in the past 15 years. Several studies have reported that the behavioral and cognitive sequelae of PME include broad deficits in the domains of attention, memory, and visual-motor integration. Knowledge regarding brain-behavior relationships is poor, however, in large part because imaging studies are rare. Hence, the effects of PME on developing neurocircuitry and brain architecture remain speculative, and are largely deductive. Some studies have implicated the dopamine-rich fronto-striatal pathways; however, cognitive deficits (e.g., impaired visual-motor integration) that should be associated with damage to those pathways are not manifested consistently across studies. We conclude by discussing challenges endemic to research on prenatal drug exposure, and argue that they may account for some of the inconsistencies in the extant research on PME. Studies confirming predicted brain-behavior relationships in PME, and exploring possible mechanisms underlying those relationships, are needed if neuroscience is to address the urgency of this growing public health problem.
Davies, K. E.; Mattei, M. G.; Mattei, J. F.; Veenema, H.; McGlade, S.; Harper, K.; Tommerup, N.; Nielsen, K. B.; Mikkelsen, M.; Beighton, P.; Drayna, D.; White, R.; Pembrey, M. E.
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One of the commonest forms of X-linked mental retardation is associated with a fragile site at Xq27 on the human X chromosome which can be visualised structurally after culturing cells in folate-deficient media. Unusually, the mutation can be transmitted through a phenotypically normal male. There is already some evidence that the gene loci for G6PD and factor IX are linked to this mental retardation locus. We have followed the inheritance of a DNA sequence 52A, in fragile site families that are also informative for factor IX. We demonstrate that these probes are localised at Xq27/Xq28-Xqter, close physically to the fragile site. We did not find close linkage between 52A, factor IX, and the fragile site in the families studied despite 52A and factor IX showing linkage in normal families. We discuss the importance of these data for the genetic mapping of this region of the human X chromosome and the implication for the use of these DNA probes for clinical diagnosis.
Lötvall, Jan; Bateman, Eric D; Busse, William W; O'Byrne, Paul M; Woodcock, Ashley; Toler, William T; Jacques, Loretta; Goldfrad, Caroline; Bleecker, Eugene R
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Current maintenance therapies for asthma require twice-daily dosing. Vilanterol (VI) is a novel long-acting beta2 agonist, under development in combination with fluticasone furoate, a new inhaled corticosteroid (ICS). Findings from a previous 4-week study suggested that VI has inherent 24-hour activity and is therefore suitable for once-daily dosing. The study described here was a double-blind, double-dummy, randomised, placebo-controlled trial, the aim of which was to assess the efficacy of once-daily VI compared with placebo in patients with persistent asthma. The primary endpoint was change from baseline in 24-hour weighted mean forced expiratory volume in 1 second after 12 weeks of treatment vs. placebo. An active control arm received salmeterol (SAL) twice daily. All patients were maintained on a stable background dose of ICS.
Patients (n = 347) received VI, placebo or SAL (1:1:1). For the primary endpoint, substantial improvements in lung function were seen with VI (359 ml), SAL (283 ml) and placebo (289 ml). There were no statistically significant treatment differences between either the VI (70 ml, P = 0.244) or SAL (-6 ml, P = 0.926) groups and placebo. Both active treatments were well tolerated, with similarly low rates of treatment-related adverse events compared with placebo. No treatment-related serious adverse events occurred.
This study failed to show a treatment difference between VI and placebo for the primary endpoint, in the presence of a placebo response of unforeseen magnitude. Because the placebo response was so large, it is not possible to draw meaningful conclusions from the data. The reason for this magnitude of effect is unclear but it may reflect increased compliance with the anti-inflammatory therapy regimen during the treatment period.
at ClinicalTrials.gov.
Howells, Fleur M.; Stein, Dan J.; Russell, Vivienne A.
A certain level of arousal is required for an individual to perform optimally, and the locus coeruleus norepinephrine (LC-NE) system plays a central role in optimizing arousal. Tonic firing of LC-NE neurons needs to be held within a narrow range of 1–3 Hz to facilitate phasic firing of the LC-NE neurons; these two modes of activity act synergistically, to allow the individual to perform attentional tasks optimally. How this information can be applied to further our understanding of psychiatric disorders has not been fully elucidated. Here we propose two models of altered LC-NE activity that result in attentional deficits characteristic of psychiatric disorders: 1) 'hypoaroused' individuals with e.g. attention-deficit/hyperactivity disorder (ADHD) have decreased tonic firing of the LC-NE system, resulting in decreased cortical arousal and poor attentional performance and 2) 'hyperaroused' individuals with e.g. anxiety disorders have increased tonic firing of the LC-NE system, resulting in increased cortical arousal and impaired attentional performance. We argue that hypoarousal (decreased tonic firing of LC-NE neurons) and hyperarousal (increased tonic firing of LC-NE neurons) are suboptimal states in which phasic activity of LC-NE neurons is impeded. To further understand the neurobiology of attentional dysfunction in psychiatric disorders a translational approach that integrates findings on the LC-NE arousal system from animal models and human imaging studies may be useful.
The clinical state of drug dependence in man is a condition of periodic or chronic intoxication produced by the repeated consumption of a drug.
Stein, O.; Stein, Y.; Coetzee, G. A.; Westhuyzen, D. R.
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Low density lipoprotein (LDL) metabolism by human skin fibroblasts was studied using LDL labeled with a nonhydrolyzable cholesteryl ether analogue,3H-cholesteryl linoleyl ether (CLE). The3H-CLE-LDL was taken up by the apo-B, E receptor mediated endocytosis similar to125I-labeled LDL. This was shown by saturation kinetics of uptake with respect to3H-CLE-LDL concentration and very low uptake of3H-CLE-LDL by receptor negative cell strains. When injected into rats,3H-CLE-LDL and14C- cholesteryl ester (CE)-LDL were cleared at equal rates and about 30% of the injected LDL was recovered in the liver. Treatment with ethinyl estradiol resulted in a three-fold increase in3H-CLE-LDL uptake by the liver. The liver is also the major site of uptake of3H-CLE-high density lipoprotein (HDL) (40%–45% of the injected dose) but its uptake by the liver increased only by 20% with estradiol treatment. As3H-CLE-HDL was cleared from the circulation at a somewhat faster rate than125I-HDL it appeared that some dissociation in the tissue uptake of the protein and CE moieties occurs.
Distiller, Greg B; Little, Francesca; Barnes, Karen I
Gametocytes are the sexual form of the malaria parasite and the main agents of transmission. While there are several factors that influence host infectivity, the density of gametocytes appears to be the best single measure that is related to the human host's infectivity to mosquitoes. Despite the obviously important role that gametocytes play in the transmission of malaria and spread of anti-malarial resistance, it is common to estimate gametocyte carriage indirectly based on asexual parasite measurements. The objective of this research was to directly model observed gametocyte densities over time, during the primary infection.
Of 447 patients enrolled in sulphadoxine-pyrimethamine therapeutic efficacy studies in South Africa and Mozambique, a subset of 103 patients who had no gametocytes pre-treatment and who had at least three non-zero gametocyte densities over the 42-day follow up period were included in this analysis.
A variety of different functions were examined. A modified version of the critical exponential function was selected for the final model given its robustness across different datasets and its flexibility in assuming a variety of different shapes. Age, site, initial asexual parasite density (logged to the base 10), and an empirical patient category were the co-variates that were found to improve the model.
A population nonlinear modeling approach seems promising and produced a flexible function whose estimates were stable across various different datasets. Surprisingly, dihydrofolate reductase and dihydropteroate synthetase mutation prevalence did not enter the model. This is probably related to a lack of power (quintuple mutations n = 12), and informative censoring; treatment failures were withdrawn from the study and given rescue treatment, usually prior to completion of follow up.
Varsani, Arvind; Monjane, Aderito L; Donaldson, Lara; Oluwafemi, Sunday; Zinga, Innocent; Komba, Ephrem K; Plakoutene, Didier; Mandakombo, Noella; Mboukoulida, Joseph; Semballa, Silla; Briddon, Rob W; Markham, Peter G; Lett, Jean-Michel; Lefeuvre, Pierre; Rybicki, Edward P; Martin, Darren P
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Panicum streak virus (PanSV; Family Geminiviridae; Genus Mastrevirus) is a close relative of Maize streak virus (MSV), the most serious viral threat to maize production in Africa. PanSV and MSV have the same leafhopper vector species, largely overlapping natural host ranges and similar geographical distributions across Africa and its associated Indian Ocean Islands. Unlike MSV, however, PanSV has no known economic relevance.
Here we report on 16 new PanSV full genome sequences sampled throughout Africa and use these together with others in public databases to reveal that PanSV and MSV populations in general share very similar patterns of genetic exchange and geographically structured diversity. A potentially important difference between the species, however, is that the movement of MSV strains throughout Africa is apparently less constrained than that of PanSV strains. Interestingly the MSV-A strain which causes maize streak disease is apparently the most mobile of all the PanSV and MSV strains investigated.
We therefore hypothesize that the generally increased mobility of MSV relative to other closely related species such as PanSV, may have been an important evolutionary step in the eventual emergence of MSV-A as a serious agricultural pathogen.
The GenBank accession numbers for the sequences reported in this paper are GQ415386-GQ415401
Thierry, M.; Lefeuvre, P.; Hoareau, M.; Péréfarres, F.; Delatte, H.; Reynaud, B.; Martin, D. P.; Lett, J.-M.
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In the 2000s, tobacco plantations on the Comoros Islands were afflicted with a previously unobserved tobacco leaf curl disease characterised by symptoms of severe leaf curling and deformation. Previous molecular characterization of potential viral pathogens revealed a complex of African monopartite tobacco leaf curl begomovirus (TbLCVs). Our molecular investigation allowed the characterization of a new monopartite virus involved in the disease: tomato leaf curl Namakely virus (ToLCNamV). Agroinoculation experiments indicated that TbLCVs and tomato leaf curl viruses (ToLCVs) can infect both tomato and tobacco but that infectivity and symptom expression fluctuate depending on the virus and the plant cultivar combination.
Tonder, Elsa C; Mahlatji, Mabatane D.; Malan, Sarel F.; Liebenberg, Wilna; Caira, Mino R.; Song, Mingna; Villiers, Melgardt M.
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The purpose of the study was to characterize the physicochemical, structural, and spectral properties of the 1∶1 niclosamide and methanol, diethyl ether, dimethyl sulfoxide, N,N' dimethylformamide, and tetrahydrofuran solvates and the 2∶1 niclosamide and tetraethylene glycol hemisolvate prepared by recrystallization from these organic solvents. Structural, spectral, and thermal analysis results confirmed the presence of the solvents and differences in the structural properties of these solvates. In addition, differences in the activation energy of desolvation, batch solution calorimetry, and the aqueous solubility at 25°C, 24 hours, showed the stability of the solvates to be in the order: anhydrate > diethyl ether solvate > tetraethylene glycol hemisolvate > methanol solvate > dimethyl sulfoxide solvate > N,N' dimethylformamide solvate. The intrinsic and powder dissolution rates of the solvates were in the order: anhydrate > diethyl ether solvate > tetraethylene glycol hemisolvate > N,N' dimethylformamide solvate > methanol solvate > dimethyl sulfoxide solvate. Although these nonaqueous solvates had higher solubility and dissolution rates than the monohydrous forms, they were unstable in aqueous media and rapidly transformed to one of the monohydrous forms.
Eden, Kate E; de Vries, Petrus J; Moss, Jo; Richards, Caroline; Oliver, Chris
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Research reporting prevalence rates of self-injurious and aggressive behaviour in people with tuberous sclerosis complex (TSC) is limited. No studies have compared rates of these behaviours in TSC with those in other syndrome groups matched for degree of disability or investigated risk markers for these behaviours in TSC.
Data from the Challenging Behaviour Questionnaire were collected for 37 children, aged 4 to 15 years, with TSC. Odds ratios were used to compare rates of self-injury and aggression in children with TSC with children with idiopathic autism spectrum disorder (ASD), fragile X, Cornelia de Lange and Down syndromes. Characteristics were measured using the Mood Interest and Pleasure Questionnaire, the Activity Questionnaire, the Social Communication Questionnaire, the Repetitive Behaviour Questionnaire, the Wessex Behaviour Schedule and the revised Non-communicating Children Pain Checklist. Mann-Whitney U analyses were used to compare characteristics between individuals with self-injury and aggression and those not showing these behaviours.
Rates of self-injury and aggression in TSC were 27% and 50%, respectively. These are high but not significantly different from rates in children with Down syndrome or other syndrome groups. Both self-injury and aggression were associated with stereotyped and pain-related behaviours, low mood, hyperactivity, impulsivity and repetitive use of language. Children who engaged in self-injury also had lower levels of interest and pleasure and showed a greater degree of 'insistence on sameness' than children who did not self-injure. Aggression was associated with repetitive behaviour. The majority of these associations remained significant when the association with level of adaptive functioning was controlled for.
Behavioural profiles can be used to identify those most at risk of developing self-injury and aggression. Further research is warranted to understand the influence of such internal factors as mood, ASD symptomatology and pain on challenging behaviour in people with intellectual disability.
Marais, Lelanie; Stein, Dan J.; Daniels, Willie M. U.
Early life stress in humans can affect the development of neurons and neurotransmitter systems and predispose an individual to the subsequent development of depression. Similarly, in rats, maternal separation causes anxiety and depressive-like behavior and decreased corticosterone levels. Patients receiving pharmacological treatment for depression often experience negative side-effects or do not respond optimally and therefore the use of exercise as alternative antidepressant treatment is investigated. The aim of the study was to see whether rats subjected to both early life stress and chronic stress later in life show differences in depressive-like behavior, neurotrophin levels, stress hormone levels and antioxidant capacity of serum after chronic voluntary exercise as treatment. Rat pups were maternally separated and one group were allowed access to running wheels for 6 weeks while control rats were also handled and put in cages without running wheels. All rats were subjected to chronic restraint stress during adulthood. A forced swim test was done to test for depressive-like behavior. Neurotrophins were measured in the ventral hippocampus and striatum; baseline stress hormones were measured in blood plasma as well as the anti-oxidative potential of serum. Compared to controls, rats that exercised had no difference in baseline stress hormones, but had decreased immobility times in the forced swim test, increased brain derived neurotrophic factor (BDNF) levels in the striatum and decreased anti-oxidative potential of their serum. The mechanism by which depressive-like behavior was improved may have been mediated through increased striatal BDNF levels, resulting in increased neuroplasticity and the prevention of neuronal death.
Soeters, Heleen Suzanne; Howells, Fleur Margaret; Russell, Vivienne Ann
Attention-deficit hyperactivity disorder (ADHD) is a behavioural disorder that has been suggested to result from disturbances in the dopaminergic system of the brain. The most effective drugs used to treat ADHD are the psychostimulants, methylphenidate and amphetamine. They block dopamine transporters and increase dopamine release, thereby increasing the extracellular concentration of dopamine and altering dopamine signaling. Drugs of abuse, such as cocaine, also block dopamine transporters, which raises the concern that treatment of children with ADHD with psychostimulants might increase their susceptibility to drug addiction. The present study was aimed at investigating whether treatment with methylphenidate at an early stage of development increased preference for ethanol in a widely used rat model for ADHD, the spontaneously hypertensive rat (SHR). SHR display the three major characteristics of ADHD (hyperactivity, impulsivity, poor sustained attention) compared to their progenitor Wistar-Kyoto (WKY) rat strain. Ethanol increased locomotor activity of SHR slightly more than WKY when injected intraperitoneally (0.6 g/kg). SHR also spent more time in the inner zone of the open field than WKY, consistent with SHR being less anxious than WKY. When given free access to ethanol-containing solutions of increasing concentration, SHR consumed less ethanol than WKY. Treatment with methylphenidate at an early age (P21 to P35) did not alter ethanol consumption in adult SHR or WKY, suggesting that it does not increase susceptibility to ethanol addiction in these rats. In vitro superfusion studies further demonstrated that preadolescent methylphenidate treatment did not have long-term effects on dopamine release in adult SHR and WKY striatum. A major finding of this study is the fact that methylphenidate treatment did not increase alcohol use in SHR.
Abay, Efrem T; van der Westuizen, Jan H; Swart, Kenneth J; Gibhard, Liezl; Lawrence, Nina; Dambuza, Ntokozo; Wilhelm, Anke; Pravin, Kendrekar; Wiesner, Lubbe
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Even though malaria is a completely preventable and treatable disease, it remains a threat to human life and a burden to the global economy due to the emergence of multiple-drug resistant malaria parasites. According to the World Malaria Report 2013, in 2012 there were an estimated 207 million malaria cases and 627,000 deaths. Thus, the discovery and development of new, effective anti-malarial drugs are required. To achieve this goal, the Department of Chemistry at the University of the Free State has synthesized a number of novel amino-alkylated chalcones and analogues, which showed in vitro anti-malarial activity against both chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains. The lead compound (NP046) was selected for a comprehensive pharmacokinetic (PK) and in vivo efficacy evaluation in a mouse model.
In vivo efficacy: Water solutions of NP046 were administered orally at 50 and 10 mg/kg using oral gavage and IV at 5 and 1 mg/kg via the dorsal penile vein to Plasmodium berghei (ANKA strain) infected male C57BL/6 mice (n = 5), once a day for four days. Blood samples were collected via tail bleeding in tubes containing phosphate buffer saline (PBS) on day five to determine the % parasitaemia by flow cytometry.
In vivo PK: NP046 solutions in water were administered orally (50 and 10 mg/kg) and IV (5 mg/kg) to male C57BL/6 mice (n = 5). Blood samples were collected via tail bleeding into heparinized tubes and analysed using a validated LC-MS/MS assay. Data obtained from the concentration-time profile was evaluated using Summit PK software to determine the PK parameters of NP046.
NP046 inhibited parasite growth for the oral and IV groups. Better parasite growth inhibition was observed for the IV group. The PK evaluation of NP046 showed low oral bioavailability (3.2% and 6% at 50 mg/kg and 10 mg/kg dose, respectively and a moderate mean half-life ranging from 3.1 to 4.4 hours.
Even though the oral bioavailability of NP046 is low, its percentage parasite growth inhibition is promising, but in order to improve the oral bioavailability, structure-activity-relationship (SAR) optimization studies are currently being conducted.
Regnard, Guy L.; Boyes, Rutledge S.; Martin, Rowan O.; Hitzeroth, Inga I.; Rybicki, Edward P.
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Captive and wild psittacines are vulnerable to the highly contagious psittacine beak and feather disease. The causative agent, beak and feather disease virus (BFDV), was recently detected in the largest remaining population of endangered Cape parrots (Poicepahlus robustus), which are endemic to South Africa. Full-length genomes were isolated and sequenced from 26 blood samples collected from wild and captive Cape parrots to determine possible origins of infection. All sequences had characteristic BFDV sequence motifs and were similar in length to those described in the literature. However, BFDV coat protein (CP) sequences from this study did not contain a previously identified bipartite nuclear localisation signal (NLS) within residues 39-56, which indicates that an alternate NLS is involved in shuttling the CP into the nucleus. Sequences from the wild population shared a high degree of similarity, irrespective of year or location, suggesting that the disease outbreak occurred close to the time when the samples were collected. Phylogenetic analysis of full-length genomes showed that the captive Cape parrot sequences cluster with those isolated from captive-bred budgerigars in KwaZulu-Natal Province, South Africa. Exposure to captive-bred Cape parrots from a breeding facility in KwaZulu-Natal is suggested as a possible source for the virus infection. Phylogenetic analysis of BFDV isolates from wild and captive Cape parrots indicated two separate infection events in different populations, which highlights the potential risk of introducing new strains of the virus into the wild population. The present study represents the first systematic investigation of BFDV virus diversity in the southern-most population of Cape parrots.
Regenmortel, Marc H. V.; Burke, Donald S.; Calisher, Charles H.; Dietzgen, Ralf G.; Fauquet, Claude M.; Ghabrial, Said A.; Jahrling, Peter B.; Johnson, Karl M.; Holbrook, Michael R.; Horzinek, Marian C.; Keil, Günther M.; Kuhn, Jens H.; Mahy, Brian W. J.; Martelli, Giovanni P.; Pringle, Craig; Rybicki, Edward P.; Skern, Tim; Tesh, Robert B.; Wahl-Jensen, Victoria; Walker, Peter J.; Weaver, Scott C.
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A proposal has been posted on the ICTV website (2011.001aG.N.v1.binomial_sp_names) to replace virus species names by non-Latinized binomial names consisting of the current italicized species name with the terminal word "virus" replaced by the italicized and non-capitalized genus name to which the species belongs. If implemented, the current italicized species name Measles virus, for instance, would become Measles morbillivirus while the current virus name measles virus and its abbreviation MeV would remain unchanged. The rationale for the proposed change is presented.
Dimatelis, J. J.; Russell, V. A.; Stein, D. J.; Daniels, W. M.
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Exposure to early life stress has been suggested to increase an individual's vulnerability to methamphetamine (MA) dependence. Although there is no cure for drug dependence, the opioid and vesicular monoamine transporter 2 (VMAT2) systems may be useful targets for treatment insofar as they play pivotal roles in the neurochemistry of addiction. Here we investigated the effects of naltrexone (opioid antagonist) and lobeline (VMAT2 inhibitor) on MA-induced place preference in adolescent rodents subjected to early life trauma (maternal separation, MS) and controls, as well as the effects on dopamine and serotonin levels in the striatum. We found: (1) maternal separation attenuated methamphetamine-induced place preference; (2) lobeline and naltrexone treatment had differential effects on serotonin and dopamine concentrations in the striatum, naltrexone increased serotonin levels in the maternally separated animals. The hypothesized effect of early adversity increasing MA-induced place preference may not be apparent in adolescence. However the data are consistent with the hypothesis that early life stress influences neurochemical pathways that predispose an individual to drug dependence.
Fazeli, Roya; Heydarnejad, Jahangir; Massumi, Hossain; Shaabanian, Mahdi; Varsani, Arvind
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The incidence and severity of tomato leaf curl disease (TLCD) is increasing worldwide. Here we assess the diversity and distribution within tomato producing areas of Iran of begomoviruses that cause this disease. Tomato with typical TLCD symptoms and asymptomatic weeds were collected in 2005 and 2006 and tested for the presence of begomovirus DNA using polymerase chain reaction (PCR). Analysis of cloned and sequenced PCR products revealed that both mono- and bipartite begomoviruses are associated with TLCD in Iran. Furthermore, our results confirmed the symptomless infection with mono- and bipartite begomoviruses of two weed species, Chrozophora hierosolymitana Spreng (Euphobiaceae) and Herniaria sp. (Caryophyllaceae). Eighteen Iranian begomovirus isolates were classified into two major groups and two or three subgroups according to the 5′-proximal 200 nucleotides of the coat protein (CP) gene or the N-terminal 600 nucleotides of the Rep gene. Whereas most of the monopartite isolates showed closest similarity to tomato yellow leaf curl virus-Gezira (TYLCV-Ge), the three bipartite isolates were most similar to Tomato leaf curl New Delhi virus (ToLCNDV). Mixed mono- and a bipartite begomovirus infections were detected in both tomato and C. hierosolymitana. Our results indicate that the tomato producing areas in central, southern, and southeastern Iran are threatened by begomoviruses originating from both the Mediterranean basin and the Indian subcontinent.
Halley-Stott, R. P.; Tanzer, F.; Martin, D. P.; Rybicki, E. P.
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Stein, Dan J.
Early life adversity predisposes individuals to the development of psychopathology in later life, especially depression and anxiety disorders. Prior history of stressors may also be a vulnerability factor for developing posttraumatic stress disorder (PTSD) in response to trauma. We examined the mechanisms underlying this phenomenon by employing two animal stress models, early maternal separation followed by later time-dependent sensitization (TDS). In animals exposed to adult TDS, those with prior early adversity did not differ from controls on tests of anxiety (elevated plus maze, open field), or HPA function (ACTH and corticosterone levels). However, those with prior early adversity had increased levels of neurotrophic factors (BDNF, NGF and NT-3) in both the dorsal and ventral hippocampus. Although early adversity is known to be associated with negative effects on neuronal function, it may also be associated with an increased ability to respond to subsequent stressors with compensatory mechanisms such as increased neurotrophic factor release.
Faure, Jacqueline; Stein, Dan J.; Daniels, William
The maternal separation (MS) paradigm is an animal model that has been successfully used to study the long term effects of child abuse and neglect. Experiments showed that animals subjected to trauma and stress early in life display behavioural, endocrinological and growth factor abnormalities at a later stage in life, results that mirrored clinical conditions. It is apparent that adverse events early in life may affect the development and maturation of the brain negatively. The purpose of the present study was to investigate whether the abnormal brain development occurring in separated animals would also enhance the development of a preference for psychostimulant drug usage. Rats were subjected to maternal deprivation and further exposed to methamphetamine-induced conditioned place preference (CPP) which primarily measures drug reward (ventral striatum) learning and memory. Apomorphine-induced locomotor activity was also assessed to investigate the effects of methamphetamine on the dorsal (primarily locomotor activity) striatal dopaminergic system. We found that four consecutive injections of methamphetamine resulted in CPP behaviour 24 h after the 4th injection. A further four injections yielded similar CPP results and this effect lasted for at least 7 days until the third CPP assessment. These animals also had decreased ACTH and corticosterone secretions, but the prolactin levels were increased. Prior exposure to maternal separation did not have any effect on the CPP test. The ACTH and corticosterone secretions were also similarly reduced. However maternal separation decreased the release of prolactin and this reduction was not evident in the separated group that received methamphetamine. There was no significant difference in the apomorphine-induced locomotor activity of normally reared animals whether they received methamphetamine or saline. Interestingly there was a significant difference in locomotor activity between the two groups of animals that were subjected to maternal deprivation. The separated animals that received methamphetamine displayed markedly reduced locomotor activity upon apomorphine administration when compared to those that were treated with saline. Taken together, we conclude that maternal deprivation differentially influences dorsal and ventral striatal regions implicating dopaminergic mechanisms.
Rene Ghislain, E; Tongo, M; Ngolle, E; Burgers, W; Dorfman, J
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Masconi, Katya L; Matsha, Tandi E; Echouffo-Tcheugui, Justin B; Erasmus, Rajiv T; Kengne, Andre P
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Missing values are common in health research and omitting participants with missing data often leads to loss of statistical power, biased estimates and, consequently, inaccurate inferences. We critically reviewed the challenges posed by missing data in medical research and approaches to address them. To achieve this more efficiently, these issues were analyzed and illustrated through a systematic review on the reporting of missing data and imputation methods (prediction of missing values through relationships within and between variables) undertaken in risk prediction studies of undiagnosed diabetes. Prevalent diabetes risk models were selected based on a recent comprehensive systematic review, supplemented by an updated search of English-language studies published between 1997 and 2014. Reporting of missing data has been limited in studies of prevalent diabetes prediction. Of the 48 articles identified, 62.5% (n = 30) did not report any information on missing data or handling techniques. In 21 (43.8%) studies, researchers opted out of imputation, completing case-wise deletion of participants missing any predictor values. Although imputation methods are encouraged to handle missing data and ensure the accuracy of inferences, this has seldom been the case in studies of diabetes risk prediction. Hence, we elaborated on the various types and patterns of missing data, the limitations of case-wise deletion and state-of the-art methods of imputations and their challenges. This review highlights the inexperience or disregard of investigators of the effect of missing data in risk prediction research. Formal guidelines may enhance the reporting and appropriate handling of missing data in scientific journals.
Vial, Henri; Taramelli, Donatella; Boulton, Ian C; Ward, Steve A; Doerig, Christian; Chibale, Kelly
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The Coordination, Rationalization, and Integration of antiMALarial drug Discovery & Development Initiatives (CRIMALDDI) Consortium, funded by the EU Framework Seven Programme, has attempted, through a series of interactive and facilitated workshops, to develop priorities for research to expedite the discovery of new anti-malarials. This paper outlines the recommendations for the development of enabling technologies and the identification of novel targets.
Screening systems must be robust, validated, reproducible, and represent human malaria. They also need to be cost-effective. While such systems exist to screen for activity against blood stage Plasmodium falciparum, they are lacking for other Plasmodium spp. and other stages of the parasite's life cycle. Priority needs to be given to developing high-throughput screens that can identify activity against the liver and sexual stages. This in turn requires other enabling technologies to be developed to allow the study of these stages and to allow for the culture of liver cells and the parasite at all stages of its life cycle.
As these enabling technologies become available, they will allow novel drug targets to be studied. Currently anti-malarials are mostly targeting the asexual blood stage of the parasite's life cycle. There are many other attractive targets that need to be investigated. The liver stages and the sexual stages will become more important as malaria control moves towards malaria elimination. Sexual development is a process offering multiple targets, even though the mechanisms of differentiation are still not fully understood. However, designing a drug whose effect is not curative but would be used in asymptomatic patients is difficult given current safety thresholds. Compounds active against the liver schizont would have a prophylactic effect and Plasmodium vivax elimination requires effectors against the dormant liver hypnozoites. It may be that drugs to be used in elimination campaigns will also need to have utility in the control phase. Compounds with activity against blood stages need to be screened for activity against other stages.
Natural products should also be a valuable source of new compounds. They often occupy non-Lipinski chemical space and so may reveal valuable new chemotypes.
Ipser, Jonathan; Stein, Dan J.
Pharmacotherapy is frequently considered in the treatment of disruptive behavior disorders (DBDs) in children and adolescents. There are, however, no systematic reviews of this literature.
The aim of this work is to determine whether medication is effective in treating pediatric disruptive behavior disorders and related problems of impulse control, as well as to examine differences in the treatment response and tolerability of different medication classes and agents.
Randomized controlled trials of the pharmacotherapy of DBDs in children and adolescents were reviewed, and a meta-analysis of 14 trials (823 participants) was conducted.
There is some evidence of the effectiveness of medication in treating DBDs, with positive outcomes for lithium and risperidone in particular. Pharmacotherapy also demonstrated some efficacy in reducing symptoms of aggression. Medication was relatively well-tolerated, as indicated by equivalent dropout rates in medication and comparison groups.
There are relatively few controlled trials of the pharmacotherapy of disruptive behavior disorders or other impulse control disorders, despite the importance of research in this area. Given the potential adverse effects of agents such as lithium and risperidone, a careful risk–benefit analysis is needed for each patient.
Lastovica, A. J.
Examination by electron microscopy has revealed 2 types of microfilament in the cytoplasm of 3 strains of axenically grownNaegleria fowleri amoebae. Thin, actin-like microfilaments 5–7 nm in diameter are randomly oriented in the nonmotile amoebae, and are concentrated near the plasma membrane. In the actively motile amoebae these microfilaments aggregate to form colateral bundles in close proximity to the plasma membrane. Thick, myosin-like microfilaments 17–19 nm in diameter also occur in the amoebae cytoplasm. The significance of these 2 kinds of microfilament in amoeboid motion is discussed.
Debevec, Tadej; Bali, Tarsi C.; Simpson, Elizabeth J.; Macdonald, Ian A.; Eiken, Ola; Mekjavic, Igor B.
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This study tested the hypothesis that hypoxia exacerbates reductions in body mass observed during unloading.
To discern the separate and combined effects of simulated microgravity and hypoxia, 11 healthy males underwent three 21-day campaigns in a counterbalanced fashion: (1) normoxic bed rest (NBR; FiO2 = 0.209; PiO2 = 133.1 ± 0.3); (2) hypoxic ambulatory confinement (HAMB; FiO2 = 0.141 ± 0.004; PiO2 = 90.0 ± 0.4; ~4,000 m); and (3) hypoxic bed rest (HBR; FiO2 = 0.141 ± 0.004; PiO2 = 90.0 ± 0.4). The same dietary menu was applied in all campaigns. Targeted energy intakes were estimated individually using the Harris–Benedict equation taking into account whether the subjects were bedridden or ambulatory. Body mass and water balance were assessed throughout the campaigns. Whole body and regional body composition was determined before and after the campaigns using dual-energy X-ray absorptiometry. Before and during the campaigns, indirect calorimetry and visual analogue scores were employed to assess the resting energy expenditure (REE) and perceived appetite sensations, respectively.
Energy intakes were lower than targeted in all campaigns (NBR: −5 %; HAMB: −14 %; HBR: −6 %; P < 0.01). Body mass significantly decreased following all campaigns (NBR: −3 %; HAMB: −4 %; HBR: −5 %; P < 0.01). While fat mass was not significantly altered, the whole body fat free mass was reduced (NBR: −4 %; HAMB: −5 %; HBR: −5 %; P < 0.01), secondary to lower limb fat-free mass reduction. Water balance was comparable between the campaigns. No changes were observed in REE and perceived appetite.
Exposure to simulated altitude of ~4,000 m does not seem to worsen the whole body mass and fat-free mass reductions or alter resting energy expenditure and appetite during a 21-day simulated microgravity.
Bruyn, G; Mlisana, K; Metch, B; Churchyard, G; Nchabeleng, M; Bekker, L; Roux, S; Naicker, N; Latka, M; Corey, L; Kublin, J; Gray, G
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Du, Zhenguo; Tang, Yafei; Zhang, Songbai; She, Xiaoman; Lan, Guobing; Varsani, Arvind; He, Zifu
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A putative circular single-stranded DNA (ssDNA) virus was recovered from Hypericum japonicum collected in Vietnam. The viral isolate was tentatively named Hypericum japonicum-associated circular DNA virus (HJasCV). HJasCV shares 58.7-65.4% nucleotide sequence identity with Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1) and SsHADV-1-like viruses. Like this group of viruses, the genome of HJasCV (2 200 nt) has two large ORFs, one in the virion-sense and the other in the complementary-sense DNA. The proteins encoded in the virion-sense and complementary-sense ORFs share 39-46 % and 45-67 % amino acid sequence identity with the putative capsid and replication-associated proteins (Reps), respectively, of SsHADV-1 and SsHADV-1-like viruses. The putative Rep of HJasCV contains all of the motifs related to rolling-circle replication. Its 111-bp intergenic region (IR) contains a hairpin structure with a geminivirus-like nonanucleotide sequence, TAATGTTAT, at the apex of the loop. Phylogenetic analysis revealed that HJasCV forms a monophyletic clade with SsHADV-1 and SsHADV-1-like viruses.
From substantial (and indisputable) evidence already outlined in the previous volume, at least 2–4% of plant species and 8–10% of animal species synthesize antineoplastic and/or cytotoxic substances. The potential of these figures for treatment of human cancer truly staggers the imagination and offers great promise of many curative approaches to the cancer problem. For some perspective one need only to consider that the world's flora may number up to 800,000 and the more conspicuous members of our terrestrial vegetation, the angiosperms, may number from 300,000 to some 500,000131,231 Further, enormous numbers of microorganism species appear to be available. In the animal segment of life the marine invertebrates alone number over 1,000,000 species, and with marine vertebrates the fishes comprise over 25,000 species. In the arthropod area the class insecta alone includes over 1,000,000 species. Since only a few percent of the known plants and less than 0.5% of the known animals have been evaluated for anticancer or cytotoxic constituents, it is apparent that we have just about reached the end of the beginning in our search for biosynthetic cancer chemotherapeutic drugs.
Ortiz-Catedral, Luis; Kurenbach, Brigitta; Massaro, Melanie; McInnes, Kate; Brunton, Dianne H.; Hauber, Mark E.; Martin, Darren P.; Varsani, Arvind
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Psittacine beak and feather disease (PBFD) is a viral disease distributed worldwide with a potentially critical impact on many rare parrots. While efforts have been made to determine its prevalence in wild and captive psittacines, only limited work has been done to document complete genomes of its causative agent, beak and feather disease virus (BFDV). Here, we describe five full genomes of BFDV isolated from wild specimens of an endemic New Zealand parrot, the red-fronted parakeet (Cyanoramphus novaezelandiae). The isolates share >99% nucleotide similarity amongst themselves and ~91–92% similarity to BFDV isolates from southern Africa, Europe and Australia. A maximum-likelihood (ML) phylogenetic tree including 42 other full-genome sequences indicated that the five isolates from red-fronted parakeets represent an undescribed genotype of BFDV. These isolates are evolutionarily most closely related to the Cacatuini isolates from Thailand and the Lorinae isolates from Australia in the rep gene ML tree; however, in the cp ML tree, the evolutionary relationship is closer to viruses found in the Psittacini.
Albuquerque, L. C.; Martin, D. P.; Ávila, A. C.; Inoue-Nagata, A. K.
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Tomato yellow vein streak virus (ToYVSV) is a tentative begomovirus (Family Geminiviridae) species that seriously affects tomato and potato production in Brazil. Here, we have determined the genomic and biological characteristics of a ToYVSV isolate (Ba3) from a potato plant sampled in Rio Grande do Sul State, Brazil. The DNA-A nucleotide sequence of Ba3 and another previously reported ToYVSV isolate share 89.7% sequence identity. These ToYVSV isolates should be classified as a new species in that they are most closely related to Soybean blistering mosaic virus with which they share only ~80% identity. Cloned constructs containing 1.5 mer copies of the ToYVSV genomic components were found, by biolistic bombardment, to be infectious in at least 11 plant species in 2 families (Solanaceae and Malvaceae). Symptoms on tomato and potato plants were identical to those originally observed on field-infected plants. ToYVSV was also sap-transmissible from Nicotiana benthamiana to N. benthamiana and tomato, but not to potato plants.
Gilreath, Tamika D.; Chaix, Basile; King, Gary; Matthews, Stephen; Flisher, Alan J.
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Tobacco use has been found to be related to contextual–environmental characteristics. This study focuses on the influence of contextual norms on adolescent smoking behavior with consideration of racial differences.
Data for this study were derived from the South African Community Epidemiology Network on Drug Use survey. Students (n = 1,277) completed a self-administered questionnaire (available in Afrikaans, Xhosa, and English). School-level aggregate measures were developed from the items: whether they thought smoking was wrong, whether they thought they would be seen as "cool" if they smoked, how many of their closest friends smoked, and whether they had repeated a grade level in school.
The results of this analysis revealed that after controlling for demographic characteristics, aggregate measures of importance for ever smoking were whether there were school norms of perceiving that smoking was not wrong, perceiving that smoking was cool, and high prevalence of having friends who smoke. Recent smoking was only predicted by attendance at schools with increased levels of academic failure. Black South Africans were less likely to ever smoke than Coloured or White.
This study highlights the saliency of both compositional (academic failure) and ecological (collective perceptions about smoking) characteristics in predicting ever and recent smoking. Collective perceptions of smoking in a predominantly Black school were largely negative. These findings can be used to target school norms regarding tobacco use in Cape Town.
Russell, Vivienne A; Oades, Robert D; Tannock, Rosemary; Killeen, Peter R; Auerbach, Judith G; Johansen, Espen B; Sagvolden, Terje
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Current concepts of Attention-Deficit/Hyperactivity Disorder (ADHD) emphasize the role of higher-order cognitive functions and reinforcement processes attributed to structural and biochemical anomalies in cortical and limbic neural networks innervated by the monoamines, dopamine, noradrenaline and serotonin. However, these explanations do not account for the ubiquitous findings in ADHD of intra-individual performance variability, particularly on tasks that require continual responses to rapid, externally-paced stimuli. Nor do they consider attention as a temporal process dependent upon a continuous energy supply for efficient and consistent function. A consideration of this feature of intra-individual response variability, which is not unique to ADHD but is also found in other disorders, leads to a new perspective on the causes and potential remedies of specific aspects of ADHD.
We propose that in ADHD, astrocyte function is insufficient, particularly in terms of its formation and supply of lactate. This insufficiency has implications both for performance and development: H1) In rapidly firing neurons there is deficient ATP production, slow restoration of ionic gradients across neuronal membranes and delayed neuronal firing; H2) In oligodendrocytes insufficient lactate supply impairs fatty acid synthesis and myelination of axons during development. These effects occur over vastly different time scales: those due to deficient ATP (H1) occur over milliseconds, whereas those due to deficient myelination (H2) occur over months and years. Collectively the neural outcomes of impaired astrocytic release of lactate manifest behaviourally as inefficient and inconsistent performance (variable response times across the lifespan, especially during activities that require sustained speeded responses and complex information processing).
Multi-level and multi-method approaches are required. These include: 1) Use of dynamic strategies to evaluate cognitive performance under conditions that vary in duration, complexity, speed, and reinforcement; 2) Use of sensitive neuroimaging techniques such as diffusion tensor imaging, magnetic resonance spectroscopy, electroencephalography or magnetoencephalopathy to quantify developmental changes in myelination in ADHD as a potential basis for the delayed maturation of brain function and coordination, and 3) Investigation of the prevalence of genetic markers for factors that regulate energy metabolism (lactate, glutamate, glucose transporters, glycogen synthase, glycogen phosphorylase, glycolytic enzymes), release of glutamate from synaptic terminals and glutamate-stimulated lactate production (SNAP25, glutamate receptors, adenosine receptors, neurexins, intracellular Ca2+), as well as astrocyte function (α1, α2 and β-adrenoceptors, dopamine D1 receptors) and myelin synthesis (lactate transporter, Lingo-1, Quaking homolog, leukemia inhibitory factor, and Transferrin).
The hypothesis extends existing theories of ADHD by proposing a physiological basis for specific aspects of the ADHD phenotype – namely frequent, transient and impairing fluctuations in functioning, particularly during performance of speeded, effortful tasks. The immediate effects of deficient ATP production and slow restoration of ionic gradients across membranes of rapidly firing neurons have implications for daily functioning: For individuals with ADHD, performance efficacy would be enhanced if repetitive and lengthy effortful tasks were segmented to reduce concurrent demands for speed and accuracy of response (introduction of breaks into lengthy/effortful activities such as examinations, motorway driving, assembly-line production). Also, variations in task or modality and the use of self- rather than system-paced schedules would be helpful. This would enable energetic demands to be distributed to alternate neural resources, and energy reserves to be re-established. Longer-term effects may manifest as reduction in regional brain volumes since brain areas with the highest energy demand will be most affected by a restricted energy supply and may be reduced in size. Novel forms of therapeutic agent and delivery system could be based on factors that regulate energy production and myelin synthesis. Since the phenomena and our proposed basis for it are not unique to ADHD but also manifests in other disorders, the implications of our hypotheses may be relevant to understanding and remediating these other conditions as well.
Ravenscroft, Neil; Costantino, Paolo; Talaga, Philippe; Rodriguez, Roberto; Egan, William
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Antibodies against the cell surface carbohydrates of many microbial pathogens protect against infection, which led to the first generation of carbohydrate vaccines based on purified bacterial polysaccharides. These polysaccharide vaccines are rapidly becoming replaced by the more immunogenic glycoconjugate vaccines in which the cell surface carbohydrate is covalently attached to an appropriate carrier protein. Compared to the corresponding polysaccharide vaccines, glycoconjugate vaccines are diverse and structurally complex, which comprise polysaccharide or oligosaccharide fragments, linked through a variety of coupling chemistries to different carrier proteins. As for polysaccharide vaccines, the potency of glycoconjugate vaccines cannot be reliably predicted by biological assays, and therefore their development, quality control, and licensure rely mostly on the physicochemical characterization of the starting polysaccharide and protein, activated or derivatized intermediates and the conjugate vaccine produced. Glycoconjugate vaccines against Haemophilus influenzae type b and selected serogroups/types of Neisseria meningitidis and Streptococcus pneumoniae have been licensed and strategies for their manufacturing, testing, and regulation established. These principles are being applied to develop conjugate vaccines against additional strains of these bacteria and other pathogens including Streptococcus, Salmonella, Staphylococcus, Escherichia coli, Klebsiella, Enterococcus, Shigella, Vibrio, as well as pathogenic fungi such as Candida albicans and Cryptococcus neoformans. These challenges are being met by the development of new conjugation strategies combined with improved analytical techniques and new approaches to making well-defined conjugates using synthetic and biosynthetic methods.
Mangisa, Nomathibane P.; Smuts, Heidi E.; Kramvis, Anna; Linley, C. Wendy; Skelton, Michelle; Tucker, Timothy J.; Hall, Pauline De La M.; Kahn, Del; Jilbert, Allison R.; Kew, Michael C.
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The objective of the study was to characterize the genome of duck hepatitis B virus (DHBV) isolates from South African Pekin ducks. Duck serum and liver samples were collected from two commercial duck farms from geographically distinct regions of South Africa. In total, 498 duck serum samples were tested for the presence of DHBV DNA using either sub-genomic or full-length polymerase chain reaction (PCR) assays. The overall prevalence of DHBV infection in South African ducks was 47%. In addition, 30% of 59 liver tissues tested were DHBV DNA-positive. Six randomly selected serum or liver samples were used to clone and sequence the genomes of the South African DHBV strains. All six isolates had DHBV genomes of 3,021 nucleotides with three characteristic overlapping reading frames encoding the polymerase, surface and core gene products. No X-like gene with a traditional start codon was found. Following phylogenetic analysis, the South African DHBV isolates clustered with DHBV isolates from other "Western" countries, including United States of America, Canada, Germany and India. On translation of the open reading frames, the South African isolates were found to share signature amino acids in the polymerase and surface genes with the "Western" country isolates as opposed to those of Chinese DHBV isolates.
Lamberts, Robert P.; Swart, Jeroen; Noakes, Timothy D.; Lambert, Michael I.
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Heart rate recovery (HRR) after submaximal exercise improves after training. However, it is unknown if this also occurs in already well-trained cyclists. Therefore, 14 well-trained cyclists (VO2max 60.3 ± 7.2 ml kg−1 min−1; relative peak power output 5.2 ± 0.6 W kg−1) participated in a high-intensity training programme (eight sessions in 4 weeks). Before and after high-intensity training, performance was assessed with a peak power output test including respiratory gas analysis (VO2max) and a 40-km time trial. HRR was measured after every high-intensity training session and 40-km time trial. After the training period peak power output, expressed as W kg−1, improved by 4.7% (P = 0.000010) and 40-km time trial improved by 2.2% (P = 0.000007), whereas there was no change in VO2max (P = 0.066571). Both HRR after the high intensity training sessions (7 ± 6 beats; P = 0.001302) and HRR after the 40-km time trials (6 ± 3 beats; P = 0.023101) improved significantly after the training period. Good relationships were found between improvements in HRR40-km and improvements in peak power output (r = 0.73; P < 0.0001) and 40-km time trial time (r = 0.96; P < 0.0001). In conclusion, HRR is a sensitive marker which tracks changes in training status in already well-trained cyclists and has the potential to have an important role in monitoring and prescribing training.
Ferrett, Helen L.; Thomas, Kevin G. F.; Tapert, Susan F.; Carey, Paul D.; Conradie, Simone; Cuzen, Natalie L.; Stein, Dan J.; Fein, George
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Interpretation of neuropsychological tests may be hampered by confounding sociodemographic factors and by using inappropriate normative data. We investigated these factors in three tests endorsed by the World Health Organization: the Grooved Pegboard Test (GPT), the Children's Color Trails Test (CCTT), and the WHO/UCLA version of the Auditory Verbal Learning Test (AVLT). In a sample of 12-15-year-old, Afrikaans- and English-speaking adolescents from the Cape Town region of South Africa, analyses of covariance (ANCOVAs) demonstrated that quality of education was the sociodemographic factor with the biggest influence on test performance, and that age also significantly influenced GPT and CCTT performance. Based on those findings, we provide appropriately stratified normative data for the age group in question. Comparisons between diagnostic interpretations made using foreign normative data versus those using the current local data demonstrate that it is imperative to use appropriately stratified normative data to guard against misinterpreting performance.
Ambele, Melvin A; Egan, Timothy J
The malaria parasite disposes of host-derived ferrihaem (iron(III)protoporphyrin IX, Fe(III)PPIX) by conversion to crystalline haemozoin in close association with neutral lipids. Lipids mediate synthetic haemozoin (β-haematin) formation very efficiently. However, the effect on reaction rates of concentrations of lipid, Fe(III)PPIX and physiologically relevant ions and biomolecules are unknown.
Lipid emulsions containing Fe(III)PPIX were prepared in aqueous medium (pH 4.8, 37°C) to mediate β-haematin formation. The reaction was quenched at various times and free Fe(III)PPIX measured colorimetrically as a pyridine complex and the kinetics and yields analysed. Products were also characterized by FTIR, TEM and electron diffraction. Autofluorescence was also used to monitor β-haematin formation by confocal microscopy.
At fixed Fe(III)PPIX concentration, β-haematin yields remained constant with decreasing lipid concentration until a cut-off ratio was reached whereupon efficiency decreased dramatically. For the haemozoin-associated neutral lipid blend (NLB) and monopalmitoylglycerol (MPG), this occurred below a lipid/Fe(III)PPIX (L/H) ratio of 0.54. Rate constants were found to increase with L/H ratio above the cut-off. At 16 μM MPG, Fe(III)PPIX concentration could be raised until the L/H ratio reached the same ratio before a sudden decline in yield was observed. MPG-mediated β-haematin formation was relatively insensitive to biologically relevant cations (Na+, K+, Mg2+, Ca2+), or anions (H2PO4−, HCO3−, ATP, 2,3-diphosphoglycerate, glutathione). Confocal microscopy demonstrated β-haematin formation occurs in association with the lipid particles.
Kinetics of β-haematin formation have shown that haemozoin-associated neutral lipids alone are capable of mediating β-haematin formation at adequate rates under physiologically realistic conditions of ion concentrations to account for haemozoin formation.
Abay, Efrem T; van der Westhuizen, Jan H; Swart, Kenneth J; Gibhard, Liezl; Tukulula, Matshawandile; Chibale, Kelly; Wiesner, Lubbe
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Malaria is one of the most lethal and life-threatening killer infectious diseases in the world, and account for the deaths of more than half a million people annually. Despite the remarkable achievement made in preventing and eradicating malaria, it still remains a threat to the public health and a burden to the global economy due to the emergence of multiple-drug resistant malaria parasites. Therefore, the need to develop new anti-malarial drugs is crucial. The chemistry department at the University of Cape Town synthesized a number of new CQ-like derivatives (TK-series), and evaluated them for in vitro activity against both CQ-sensitive and -resistant Plasmodium falciparum strains, and for general cytotoxicity against a Chinese Hamster Ovarian (CHO) mammalian cell line. The lead compounds from the TK-series were selected for a comprehensive pharmacokinetic (PK) evaluation in a mouse model.
A sensitive LC-MS/MS assay was developed for the quantitative determination of TK900D. Multiple reaction monitoring (MRM) in the positive ionization mode was used for detection. The analyte and the internal standard (TK900E) were isolated from blood samples by liquid-liquid extraction with ethyl acetate. Chromatographic separation was achieved with a Phenomenex® Kinetex C18 (100 × 2.0 mm id, 2.6 μm) analytical column, using a mixture of 0.1% formic acid and acetonitrile (50:50; v/v) as the mobile phase. The method was fully validated over concentrations that ranged from 3.910 to 1000 ng/ml, and used to evaluate the PK properties of the lead compounds in a mouse model.
The assay was robust, with deviation not exceeding 11% for the intra- and inter-run precision and accuracy. Extraction recovery was consistent and more than 60%. PK evaluation showed that TK900D and TK900E have moderate oral bioavailability of 30.8% and 25.9%, respectively. The apparent half-life ranged between 4 to 6 h for TK900D and 3.6 to 4 h for TK900E.
The assay was sensitive and able to measure accurately low drug levels from a small sample volume (20 μl). PK evaluation showed that the oral bioavailability was moderate. Therefore, from a PK perspective, the compounds look promising and can be taken further in the drug development process.
Firnhaber, Cynthia; Le, Hoa; Pettifor, Audrey; Schulze, Doreen; Michelow, Pam; Sanne, Ian M.; Lewis, David A.; Williamson, Anna-Lise; Allan, Bruce; Williams, Sophia; Rinas, Allen; Levin, Simon; Smith, Jennifer S.
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To examine the association between CD4 counts, HPV infection and the risk of cervical neoplasia among HIV-seropositive women.
A cross-sectional observational study was conducted among 1,010 HIV-seropositive women using cytology-based Pap smears. HPV DNA testing using Linear Array genotyping assay (Roche) was carried out in a subset of 191 patients. Multivariable-adjusted prevalence ratios (mPR) and 95% confidence intervals (CIs) were estimated with log-binomial regression.
Among 1,010 HIV-seropositive women, the prevalence of AGC/ASCUS, LSIL and HSIL or greater was 8.3, 23.5 and 18.0%, respectively. The risk of cervical lesions was higher with CD4 < 200 cells/mm3 vs. CD4 levels > 500/mm3. HPV types 16 (41.7%) and HPV 56 (22.2%) were the most common types in HSIL cases. Women with CD4 levels < 200/mm3 had a higher prevalence of HPV types 16 (p < 0.01) and 66 (p = 0.04). No statistical relationship between cervical lesions and HAART use was found.
The burden of HPV infection and HSIL was high and correlated with HIV-induced immunosuppression. HPV 16 was the most common type in HSIL and increased in prevalence with greater immune suppression. Prophylactic HPV 16 vaccination could prevent approximately 40% of HSIL cases. Strengthening screening programs is imperative in this population.
Hughes, F. L.; Rybicki, E. P.; Kirby, R.
The complete nucleotide sequence of the genome of the Monogeminivirus sugarcane streak virus (SSV) was determined from cloned replicative form DNA. The genome is contained in one DNA circle of 2 758 nucleotides, and has four open reading frames with the potential to encode proteins of MW >10 kDa: two in the viral (+) sense and two in the complementary (−) sense. Each open reading frame has a counterpart among the open reading frames reported for other Monogeminiviruses. A potential binding site for a DNA replication primer and potential transcriptional control sequences were identified on the (+) strand, and a possible intron on the (−) strand. Phylogenetic analysis of coat protein and replication-associated protein sequences of SSV and other grass-infecting geminiviruses indicate that SSV, although distinct from any other virus, is part of an "African streak virus subgroup" of Monogeminiviruses.
Nicolson, Sue; Isaacson, Leon; Gerneke, Dane
Access to the basal membrane of beetle Malpighian tubules (Onymacris rugatipennis) was achieved by a new method of stripping tubules of the surrounding connective tissue and basement membrane, in a simple squeezing process. We recorded single channel currents in the cell-attached configuration from basal K+ channels. The peeling method described, in this paper allows quick and easy preparation of Malpighian tubules for patch clamp studies on the basal membrane.
Williamson, C.; Rybicki, E. P.
The genomic RNAs of aphid lethal paralysis virus (ALPV) andRhopalosiphum padi virus (RhPV)—two distinct picorna-like viruses found in aphids [Williamson et al. (1988) J Gen Virol 69: 787–795]—were both efficiently translated in rabbit reticulocyte lysates. ALPV RNA was translated into primary products with molecular weights ranging from 92 kDa to 170 kDa. These underwent time-dependent post-translational cleavage to produce smaller polypeptides including some with molecular weights comparable to those of the viral structural proteins. A 92 kDa polypeptide as well as smaller proteins were immunoprecipitated with capsid protein antisera, indicating the presence of at least one large capsid subunit protein precursor. RhPV RNA was translated into products of molecular weights ranging from 45 kDa to 175 kDa. There was no evidence for time-dependent post-translation cleavage of RhPV translation products. However, a 60 kDa polypeptide was precipitated with antiserum to RhPV virions, indicating that at least one capsid protein of RhPV is derived by proteolysis of a precursor protein, like those of ALPV and most other picornaviruses.
Farkas, Kata; Varsani, Arvind; Pang, Liping
Adsorption to aquifer media is an important process in the removal of viruses from groundwater. Even though hydrophobic interactions have been shown to contribute to adsorption, little is known about the hydrophobicity of viruses found in groundwater. In this study, the hydrophobicity of rotavirus, MS2 bacteriophage and DNA-labelled silica nanoparticles (SiNPs) coated with glycoprotein, protein A and alpha-1-microglobulin/bikunin precursor (AMBP) was investigated. The hydrophobicity was experimentally determined by using a modified microbial adhesion to hydrocarbons (MATH) assay. The results were compared with the theoretical hydrophobicity of the viral capsid proteins and the proteins used to coat the nanoparticles, and with the results of adsorption tests with unmodified and organosilane-coated (hydrophobic) silica sand. While most theoretical protein hydrophobicity values were similar, the results of the MATH assay suggested fundamental differences in the hydrophobicity of the viruses and the SiNPs. MS2 was found to be highly hydrophobic as based on the MATH hydrophobicity and a significantly enhanced adsorption to hydrophobic sand, whereas rotavirus was relatively hydrophilic. The MATH assay revealed that protein-coating of SiNP introduced some degree of hydrophobicity to hydrophilic SiNPs, enabling them to more closely mimic viral hydrophobicity. Our study also demonstrated that the protein-coated SiNPs better mimicked rotavirus adsorption to sand media (coated or not coated with hydrophobic organic matter) than the MS2. This further supports previous findings that these surface-modified SiNPs are useful surrogates in mimicking rotavirus retention and transport in porous media.
Chege, GK; Chapman, R; Shephard, EG; Williamson, A
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Lehohla, Molupe; Kellaway, Lauriston; Russell, Vivienne Ann
The spontaneously hypertensive rat (SHR) is an accepted model for attention-deficit hyperactivity disorder (ADHD) since it displays the major symptoms of ADHD (hyperactivity, impulsivity, and poor performance in tasks that require sustained attention). We have previously shown that glutamate activation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors released significantly more norepinephrine from SHR prefrontal cortex slices than control Wistar-Kyoto (WKY) rats. The aim of this study was to determine whether N-methyl-D-aspartate (NMDA) receptor function is disturbed in the prefrontal cortex of SHR. Prefrontal cortex slices were incubated with 45Ca2+ in the presence or absence of 100 μM NMDA for 2 min. Activation of NMDA receptors stimulated significantly less Ca2+ uptake into prefrontal cortex slices of SHR than control WKY (2.8 ± 0.17 vs. 3.7 ± 0.38 nmol/mg protein, respectively, P < 0.05). Basal Ca2+ uptake into SHR slices was not significantly different from WKY. These findings are consistent with suggestions that the intracellular concentration of calcium is elevated and therefore the concentration gradient that drives calcium into the cell is decreased in SHR compared to WKY. Impaired NMDA receptor function in the prefrontal cortex of SHR could give rise to impaired cognition and an inability to sustain attention.
Silal, Sheetal P; Little, Francesca; Barnes, Karen I; White, Lisa J
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South Africa is one of many countries committed to malaria elimination with a target of 2018 and all malaria-endemic provinces, including Mpumalanga, are increasing efforts towards this ambitious goal. The reduction of imported infections is a vital element of an elimination strategy, particularly if a country is already experiencing high levels of imported infections. Border control of malaria is one tool that may be considered.
A metapopulation, non-linear stochastic ordinary differential equation model is used to simulate malaria transmission in Mpumalanga and Maputo province, Mozambique (the source of the majority of imported infections) to predict the impact of a focal screen and treat campaign at the Mpumalanga–Maputo border. This campaign is simulated by nesting an individual-based model for the focal screen and treat campaign within the metapopulation transmission model.
The model predicts that such a campaign, simulated for different levels of resources, coverage and take-up rates with a variety of screening tools, will not eliminate malaria on its own, but will reduce transmission substantially. Making the campaign mandatory decreases transmission further though sub-patent infections are likely to remain undetected if the diagnostic tool is not adequately sensitive. Replacing screening and treating with mass drug administration results in substantially larger decreases as all (including sub-patent) infections are treated before movement into Mpumalanga.
The reduction of imported cases will be vital to any future malaria control or elimination strategy. This simulation predicts that FSAT at the Mpumalanga–Maputo border will be unable to eliminate local malaria on its own, but may still play a key role in detecting and treating imported infections before they enter the country. Thus FSAT may form part of an integrated elimination strategy where a variety of interventions are employed together to achieve malaria elimination.
Akindipe, Taiwo; Wilson, Don; Stein, Dan J.
Methamphetamine dependence may be associated with a range of psychiatric disorders. However, relatively few studies have systematically examined these disorders and possible risk factors. This study used a structured diagnostic interview to assess the prevalence and pattern of co-morbid psychiatric disorders in individuals with methamphetamine dependence; and identified risk factors for this comorbidity. One hundred adult volunteers with a diagnosis of methamphetamine dependence and without co-morbid medical disorders were consecutively recruited from three drug rehabilitation centres. Each volunteer was assessed with a socio-demographic questionnaire and evaluated for psychiatric comorbidity using the Structured Clinical Interview for DSM-IV Axis I disorders (SCID-I). A regression model was used to determine predictors of psychiatric comorbidity. Co-morbid psychiatric disorders were present in 36.0 % of the sample; these included mood disorders (16.0 %), psychotic disorders (13.0 %) and anxiety disorders (7.0 %). One in four of these disorders were assessed as being substance-induced. Independent predictors of psychiatric comorbidity included being male (OR = 10.04, 95 % C.I = 2.07–48.63, p = 0.004), younger (OR = 0.87, 95 % C.I = 0.77–0.99, p = 0.04), and having a previous psychiatric disorder (OR = 18.45, 95 % C.I = 3.81–89.33, p < 0.001). Mood, psychotic, and anxiety disorders are common in individuals with methamphetamine dependence. Risk factors for such comorbidity can be identified. These findings underscore the need for an integrated model of care addressing both substance use disorders and psychiatric comorbidity.
Sloan, A. W.; Koeslag, J. H.; Bredell, G. A. G.
On 46 healthy young men, of whom 18 took part in strenuous sport at least once a week, height, weight, total body fat (as % of body mass) and lean body mass (LBM) were determined. The subjects performed submaximal exercise on a bicycle ergometer and climbing on an upwardly inclined treadmill at work loads of 60, 110, and 140 watts. Oxygen consumption (
$$\dot V_{O_2 }$$
), respiratory quotient (RQ), energy expenditure (ė), and heart rate (fH) were measured at rest and at each work load, and maximum oxygen intake (
$$\dot V_{O_2 }$$
max) and physical work capacity (PWC150, PWC170) were calculated.
Anthropometric parameters did not differ significantly between sportsmen and sedentary subjects.
$$\dot V_{O_2 }$$
max, PWC150, and PWC170 had higher correlations with LBM than with the other anthropometric parameters.
$$\dot V_{O_2 }$$
max expressed in terms of LBM (ml/kg LBM/min) was the parameter which showed the clearest distinction between sportsmen and sedentary individuals. The sportsmen had higher
$$\dot V_{O_2 }$$
max on the treadmill test than on the bicycle ergometer. PWC150 and PWC170 were higher on the bicycle than on the treadmill and had high correlations with
$$\dot V_{O_2 }$$
max. Work efficiency was of the same order in both groups and showed negative correlation with the degree of obesity on the bicycle ergometer and positive correlation on the treadmill.
Hadfield, James; Linderme, Daphné; Shepherd, Dionne N.; Bezuidenhout, Marion; Lefeuvre, Pierre; Martin, Darren P.; Varsani, Arvind
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Dahlia mosaic disease of the ornamental flowering plant Dahlia is caused by two caulimoviruses, dahlia mosaic virus (DMV) and dahlia common mosaic virus (DCMV). We used a rolling-circle amplification method to amplify, clone and determine for the first time the full genome sequence of a DCMV isolate from New Zealand (DCMV-NZ). Within the 7949-bp circular double-stranded retro-transcribing DCMV-NZ DNA, we identified six putative open reading frames, typical of all genomes in the family Caulimoviridae. The availability of the complete DCMV sequence provides a reference genome against which all others can be compared.
Fletcher, Helen A; Keyser, Alana; Bowmaker, Mark; Sayles, Peter C; Kaplan, Gilla; Hussey, Greg; Hill, Adrian VS; Hanekom, Willem A
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Novel tuberculosis (TB) vaccines recently tested in humans have been designed to boost immunity induced by the current vaccine, Mycobacterium bovis Bacille Calmette-Guérin (BCG). Because BCG vaccination is used extensively in infants, this population group is likely to be the first in which efficacy trials of new vaccines will be conducted. However, our understanding of the complexity of immunity to BCG in infants is inadequate, making interpretation of vaccine-induced immune responses difficult.
To better understand BCG-induced immunity, we performed gene expression profiling in five 10-week old infants routinely vaccinated with BCG at birth. RNA was extracted from 12 hour BCG-stimulated or purified protein derivative of tuberculin (PPD)-stimulated PBMC, isolated from neonatal blood collected 10 weeks after vaccination. RNA was hybridised to the Sentrix® HumanRef-8 Expression BeadChip (Illumina) to measure expression of >16,000 genes.
We found that ex vivo stimulation of PBMC with PPD and BCG induced largely similar gene expression profiles, except that BCG induced greater macrophage activation. The peroxisome proliferator-activated receptor (PPAR) signaling pathway, including PPAR-γ, involved in activation of the alternative, anti-inflammatory macrophage response was down-regulated following stimulation with both antigens. In contrast, up-regulation of genes associated with the classic, pro-inflammatory macrophage response was noted. Further analysis revealed a decrease in the expression of cell adhesion molecules (CAMs), including integrin alpha M (ITGAM), which is known to be important for entry of mycobacteria into the macrophage. Interestingly, more leukocyte genes were down-regulated than up-regulated.
Our results suggest that a combination of suppressed and up-regulated genes may be key in determining development of protective immunity to TB induced by vaccination with BCG.
Hoare, Jacqueline; Westgarth-Taylor, Jenny; Fouche, Jean-Paul; Spottiswoode, Bruce; Paul, Robert; Thomas, Kevin; Stein, Dan; Joska, John
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Sterley, Toni-Lee; Howells, Fleur M.; Dimatelis, Jacqueline J.; Russell, Vivienne A.
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Attention-deficit/hyperactivity disorder (ADHD) is one of the most common child psychiatric disorders. While it is typically treated with medications that target dopamine and norepinephrine transmission, there is increasing evidence that other neurotransmitter systems, such as glutamate and GABA, may be involved. The aetiology of ADHD is unknown; however, there is evidence that early life stress may contribute to the development of the disorder. In the present study we used proteomic analysis (iTRAQ) followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blot analysis to investigate hippocampal protein profiles of three rat strains: an animal model of ADHD, spontaneously hypertensive rats (SHR), their control Wistar-Kyoto rats (WKY), and Sprague-Dawley rats (SD). We additionally investigated how these protein profiles are affected by maternal separation, a model of early life stress. Our findings show that solute carrier family 12 member 5 (KCC2) is increased in SHR hippocampus. The glutamate transporter GLT1 splice variant, GLT1b, was increased (proteomic analysis) while total GLT1 (comprised mostly of GLT1a splice variant) was reduced (Western blot analysis) in SHR hippocampus, compared to WKY and SD – a pattern that is consistent with elevated extracellular glutamate levels. Maternal separation increased total GLT1 in hippocampi of SHR, WKY, and SD, and reduced GLT1b in SHR hippocampus. Together these findings provide evidence for disturbed glutamatergic and GABAergic transmission in SHR hippocampus, maternal separation effects on glutamate uptake in hippocampi of all three strains, as well a unique effect of maternal separation on GLT1b levels in SHR hippocampus. These data suggest significant involvement of glutamatergic and GABAergic transmission in the neuropathophysiology of ADHD, and implicates changes in glutamatergic transmission as a result of early life stress.
Kraberger, Simona; Mumtaz, Huma; Claverie, Sohini; Martin, Darren P.; Briddon, Rob W.; Varsani, Arvind
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Although members of five distinct viral species in the genus Mastrevirus (family Geminiviridae) infect dicotyledonous plants in Australia, in the remainder of the world, only a single dicot-infecting mastrevirus, chickpea chlorotic dwarf virus (CpCDV) has ever been identified. This virus has been found infecting leguminous hosts in Africa, the Middle East and the Indian subcontinent. To further explore the diversity of CpCDV in Pakistan, ten full mastrevirus genome sequences from chickpea and lentil plants were determined. Eight of these genomes were from previously described CpCDV strains and included the first reported strain D and H isolates in Pakistan. Two other genomes derived from infected chickpea plants are more closely related to dicot-infecting mastreviruses found in Australia than they are to CpCDV. These two divergent genomes shared less than 75 % genome-wide nucleotide sequence identity with other characterised mastreviruses and therefore are likely to belong to a second species of dicot-infecting mastreviruses outside of Australia. We propose naming this species Chickpea yellow dwarf virus. We discuss how the presence of chickpea yellow dwarf virus (CpYDV) in Pakistan weakens the hypothesis that Australia is the geographical origin of the dicot-infecting mastreviruses.
Donald, Kirsten A.; Fouche, J. P.; Roos, Annerine; Koen, Nastassja; Howells, Fleur M.; Riley, Edward P.; Woods, Roger P.; Zar, Heather J.; Narr, Katherine L.; Stein, Dan J.
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Neuroimaging studies have indicated that prenatal alcohol exposure is associated with alterations in the structure of specific brain regions. However, the temporal specificity of such changes and their behavioral consequences are less known. Here we explore the brain structure of infants with in utero exposure to alcohol shortly after birth. T2 structural MRI images were acquired from 28 alcohol-exposed infants and 45 demographically matched healthy controls at 2–4 weeks of age on a 3T Siemens Allegra system as part of large birth cohort study, the Drakenstein Child Health Study (DCHS). Neonatal neurobehavior was assessed at this visit; early developmental outcome assessed on the Bayley Scales of Infant Development III at 6 months of age. Volumes of gray matter regions were estimated based on the segmentations of the University of North Carolina neonatal atlas. Significantly decreased total gray matter volume was demonstrated for the alcohol-exposed cohort compared to healthy control infants (p < 0.001). Subcortical gray matter regions that were significantly different between groups after correcting for overall gray matter volume included left hippocampus, bilateral amygdala and left thalamus (p < 0.01). These findings persisted even when correcting for infant age, gender, ethnicity and maternal smoking status. Both early neurobehavioral and developmental adverse outcomes at 6 months across multiple domains were significantly associated with regional volumes primarily in the temporal and frontal lobes in infants with prenatal alcohol exposure. Alcohol exposure during the prenatal period has potentially enduring neurobiological consequences for exposed children. These findings suggest the effects of prenatal alcohol exposure on brain growth is present very early in the first year of life, a period during which the most rapid growth and maturation occurs.
Mumtaz, Huma; Kumari, Safaa G.; Mansoor, Shahid; Martin, Darren P.; Briddon, Rob W.
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Chickpea stunt disease (CSD) across southern Asia, the Middle East and North Africa is caused by a number of viruses that include single-stranded DNA viruses of the genus Mastrevirus (family Geminiviridae). Despite the importance of CSD in reducing chickpea and lentil production, until recently little was known of the nature of the pathogens causing the disease. Sequence characterisation of virus isolates from Sudan and Pakistan showed the viruses concerned to potentially be new mastrevirus species related to Bean yellow dwarf virus (BeYDV), a virus known to occur in both southern Africa and southern Asia. Here we have determined the complete nucleotide sequence of a mastrevirus associated with CSD in Syria. This virus represents a proposed new species, closely related to the recently characterised Chickpea chlorotic dwarf Sudan virus and Chickpea chlorotic dwarf Pakistan virus but with the highest sequence identity to BeYDV, for which we propose the name Chickpea chlorotic dwarf Syria virus. In addition the biological integrity of the clone was confirmed by infection of Nicotiana benthamiana plants using Agrobacterium-mediated inoculation.
Wilkins, Justin J.; Langdon, Grant; McIlleron, Helen; Pillai, Goonaseelan (Colin); Smith, Peter J.; Simonsson, Ulrika S. H.
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Windram, Oliver P.; Weber, Brandon; Jaffer, Mohamed A.; Rybicki, Edward P.; Shepherd, Dionne N.; Varsani, Arvind
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Development of vaccine strategies against human papillomavirus (HPV), which causes cervical cancer, is a priority. We investigated the use of virus-like particles (VLPs) of the most prevalent type, HPV-16, as carriers of foreign proteins. Green fluorescent protein (GFP) was fused to the N or C terminus of both L1 and L2, with L2 chimeras being co-expressed with native L1. Purified chimaeric VLPs were comparable in size (∼55 nm) to native HPV VLPs. Conformation-specific monoclonal antibodies (Mabs) bound to the VLPs, thereby indicating that they possibly retain their antigenicity. In addition, all of the VLPs encapsidated DNA in the range of 6–8 kb.
Sweijd, N. A.; Bowie, R. C. K.; Evans, B. S.; Lopata, A. L.
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Biochemical and molecular species identification techniques have a broad range of applications in the management and conservation of marine organisms. While species boundaries are not always clearly defined, phylogeneticists utilise autapomorphic characters to distinguish phylogenetic species. Genetic markers discriminate between marine taxa when traditional morphological distinctions are unclear. The applications of these techniques can be divided into four general categories. Firstly, compliance enforcement, which often depends on genetic identification techniques to enable officials to identify the species to which regulations pertain. Secondly, quality control applications, to allow for the testing of marine products to guard against fraudulent substitution with less valuable species, which is particularly pertinent since processing often obliterates identifiable features. Thirdly, a variety of applications to ecological and life-history studies and conservation management are reported. Here, the genetic identification techniques of species from cryptic life-cycle stages or of morphologically indistinct species are an indispensable tool for marine scientists, conservators and managers. Lastly, the application of genetic techniques for sourcing population origin is briefly discussed. The biochemical and molecular techniques applied to species identification all exploit phenotypic or genotypic polymorphisms that are sampled using either tertiary level protein based methods or primary level DNA based methods. In this review, examples of the applications along with the total protein, allozyme, serological, PCR and other DNA based methodologies are briefly described and some generalities with regard to their use are presented.
Lombard, Marli C; N'Da, David D; Tran Van Ba, Christophe; Wein, Sharon; Norman, Jennifer; Wiesner, Lubbe; Vial, Henri
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Because Plasmodium falciparum displays increase tolerance against the recommended artemisinin combination therapies (ACT), new classes of anti-malarial drugs are urgently required. Previously synthesized artemisinin-aminoquinoline hybrids were evaluated to ascertain whether the potent low nanomolar in vitro anti-plasmodial activity would carry over in vivo against Plasmodium vinckei. A snapshot pharmacokinetic analysis was carried out on one of the hybrids to obtain an indication of the pharmacokinetic properties of this class of anti-malarial drugs.
In vitro activity of hybrids 2 and 3 were determined against the 3D7 strain of P. falciparum. Plasmodium vinckei-infected mice were treated with hybrids 1 – 3 for four days at a dosage of 0.8 mg/kg, 2.5 mg/kg, 7.5 mg/kg or 15 mg/kg intraperitoneally (ip), or orally (per os) with 2.7 mg/kg, 8.3 mg/kg, 25 mg/kg or 50 mg/kg. Artesunate was used as reference drug. A snapshot oral and IV pharmacokinetic study was performed on hybrid 2.
Hybrids 1 – 3 displayed potent in vivo anti-malarial activity with ED50 of 1.1, 1.4 and <0.8 mg/kg by the ip route and 12, 16 and 13 mg/kg per os, respectively. Long-term monitoring of parasitaemia showed a complete cure of mice (without recrudescence) at 15 mg/kg via ip route and at 50 mg/kg by oral route for hybrid 1 and 2, whereas artesunate was only able to provide a complete cure at 30 mg/kg ip and 80 mg/kg per os.
These compounds provide a new class of desperately needed anti-malarial drug. Despite a short half-life and moderate oral bioavailability, this class of compounds was able to cure malaria in mice at very low dosages. The optimum linker length for anti-malarial activity was found to be a diaminoalkyl chain consisting of two carbon atoms either methylated or unmethylated.
Heydarnejad, Jahangir; Mozaffari, Azadeh; Massumi, Hossain; Fazeli, Roya; Gray, Alistair J. A.; Meredith, Sandra; Lakay, Francisco; Shepherd, Dionne N.; Martin, Darren P.; Varsani, Arvind
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Tomato leaf curl disease (TLCD) and and tomato yellow leaf curl (TYLCD) is caused by a number of begomovirus species that collectively threaten tomato production worldwide. We report here that an ongoing TLCD and TYLCD epidemic in Iran is caused by variants of tomato leaf curl Palampur virus (ToLCPMV), a newly proposed begomovirus species previously only detected in India. Besides infecting tomatoes, we identified ToLCPMV as the causal agent of a cucurbit disease that has devastated greenhouse cucumber and melon farms in Jiroft, southeastern Iran. We found no convincing evidence that the ToLCPMV DNA-B sequences have been derived through inter-species recombination, however, all of the currently sampled ToLCPMV DNA-A sequences are descendents of a sequence that probably arose through recombination between a ToLCNDV isolate and a currently unsampled geminivirus species that falls outside the ToLCNDV-ToLCPMV cluster. The increasing incidence of ToLCPMV in different cultivated species throughout Iran may signal the emergence of a serious new threat to agricultural production throughout the Middle East.
Warner, Digby F.; Tønjum, Tone; Mizrahi, Valerie
Fundamental aspects of the lifestyle of Mycobacterium tuberculosis implicate DNA metabolism in bacillary survival and adaptive evolution. The environments encountered by M. tuberculosis during successive cycles of infection and transmission are genotoxic. Moreover, as an obligate pathogen, M. tuberculosis has the ability to persist for extended periods in a subclinical state, suggesting that active DNA repair is critical to maintain genome integrity and bacterial viability during prolonged infection. In this chapter, we provide an overview of the major DNA metabolic pathways identified in M. tuberculosis, and situate key recent findings within the context of mycobacterial pathogenesis. Unlike many other bacterial pathogens, M. tuberculosis is genetically secluded, and appears to rely solely on chromosomal mutagenesis to drive its microevolution within the human host. In turn, this implies that a balance between high versus relaxed fidelity mechanisms of DNA metabolism ensures the maintenance of genome integrity, while accommodating the evolutionary imperative to adapt to hostile and fluctuating environments. The inferred relationship between mycobacterial DNA repair and genome dynamics is considered in the light of emerging data from whole-genome sequencing studies of clinical M. tuberculosis isolates which have revealed the potential for considerable heterogeneity within and between different bacterial and host populations.
Roberts, Craig W.; Horsnell, William G. C.
Protozoan and helminth parasites infect billions of people throughout the world and are responsible for significant morbidity and mortality of millions of people annually. Gender and cultural differences account for some dichotomy in the prevalence and intensity of infection between male and female humans. However, intrinsic differences in the biology, including the endocrine and immune systems, of male and female humans exert profound influence on disease pathogenesis. Generally, females are more resistant than males to many parasitic diseases, although exceptions exist, such as some cestode infections and Toxoplasma gondii. However, during pregnancy when a number of hormones are significantly increased and the immune system altered, females tend to be more susceptible than nonpregnant females and males to a number of parasitic infections. This is most notable for infections that rely on a helper T cell type 1 (Th1) response for resolution that is antagonized by the Th2/regulatory T (Treg) environment induced during pregnancy. As a corollary, infections that induce a strong Th1 response can disrupt pregnancy through ablating pregnancy-induced immune alterations. Some evidence is emerging that children born to mothers with parasitic infections can have lesions in their immune systems leading to tolerance or allergy as well as potential psycho-neurological changes leading to disease. There is increasing evidence that pharmacokinetics of drugs including anti-infectives can vary between the sexes. Many drugs used to treat parasitic infection (particularly protozoan infections) are far from ideal and have associated side effects. Tailored optimization of dosing regimens for men, women, and pregnant women for these drugs might be especially beneficial. New interventions optimized for sex and endocrine conditions could have greatest impact on the most disadvantaged groups in terms of susceptibility of disease including men and pregnant women.
Lehohla, Molupe; Russell, Vivienne; Kellaway, Lauriston; Govender, Ashnee
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The rat is a nocturnal animal and uses its vibrissae extensively to navigate its environment. The vibrissae are linked to a highly organized part of the sensory cortex, called the barrel cortex which contains spiny neurons that receive whisker specific thalamic input and distribute their output mainly within the cortical column. The aim of the present study was to develop a method to evaluate glutamate receptor function in the rat barrel cortex. Long Evans rats (90 – 160g) were killed by cervical dislocation and decapitated. The brain was rapidly removed, cooled in a continuously oxygenated, ice-cold Hepes buffer (pH 7.4) and sliced using a vibratome to produce 0.35mm slices. The barrel cortex was dissected from slices corresponding to 8.6 to 4.8mm anterior to the interaural line and divided into rostral, middle and caudal regions. Depolarization-induced uptake of 45Ca2+ was achieved by incubating test slices in a high K+ (62.5mM) buffer for 2 minutes at 35°C. Potassium-stimulated uptake of 45Ca2+ into the rostral region was significantly lower than into middle and caudal regions of the barrel cortex. Glutamate had no effect. NMDA significantly increased uptake of 45Ca2+ into all regions of the barrel cortex. The technique is useful in determining NMDA receptor function and will be applied to study differences between spontaneously hypertensive rats (SHR) that are used as a model for attention deficit disorder and their normotensive control rats.
Wonkam, Ambroise; Mba, Caryl Zameyo; Mbanya, Dora; Ngogang, Jeanne; Ramesar, Raj; Angwafo, Fru F., III
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Sickle Cell Disease (SCD) is a debilitating illness that affects quality of life. Studies of the psychosocial burden of SCD on patients have been rarely reported in Africa. We used a quantitative method, with face-to-face administered questionnaires, to study indices of psychosocial stressors on adult SCD patients in Cameroon. The questionnaire included a 36-item stress factors scale evaluating general perceptions of stress and five main stressors' domain: disease factors, hospital factors, financial factors, family factors and quality of personal-life factors. Items pertaining to psychosocial stressors involved four response options with increasing severity: 0, 1, 2 or 3. Non-parametric tests were used for analysis. The majority of the 83 participants were urban dwellers, female, 20–30 years old, single, unemployed, with at least a secondary or tertiary education. Median age at diagnosis was 100 months; 47.8 % had >3 painful vaso-oclusive crises annually. Only 4.8 % had been treated with hydroxyurea. The majority reported moderate to severe difficulty coping with SCD. The "degree of clinical severity" category displayed the highest median score (2.0), while familial stressors showed the lowest (0.8). Being female, married, with low education level, an additional affected sibling and low direct income were significantly associated with specific stressors' categories. In Cameroon, there is an urgent need to implement policies that ensure affordable access to health-care and practices to reduce SCD morbidity and improve patients' quality of life.
Albuquerque, Leonardo C.; Varsani, Arvind; Fernandes, Fernanda R.; Pinheiro, Bruna; Martin, Darren P.; Tarso Oliveira Ferreira, Paulo; Lemos, Thaís Oliveira; Inoue-Nagata, Alice K.
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Tomato cultivation in Brazil is threatened by a number of tomato-infecting viruses belonging to the genus Begomovirus of the family Geminiviridae. Here, we report the full DNA-A sequences of three Brazilian begomoviruses: a potentially new tomato-infecting viruses, tomato interveinal chlorosis virus (ToICV), and two previously proposed begomoviruses for which only partial DNA-A sequences are available in the databases: tomato mottle leaf curl virus (TMoLCV) and tomato golden vein virus (TGVV). The complete sequences of the DNA-B components of TMoLCV and TGVV and the DNA-A components of a number of tomato severe rugose virus variants are also presented. Collectively, all of the analyzed sequences were phylogenetically clustered within the two major groups of Brazilian tomato-infecting begomoviruses.
Mabandla, Musa V.; Kellaway, Lauriston A.; Daniels, William M. U.; Russell, Vivienne A.
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Prenatal stress has been associated with increased vulnerability to psychiatric disturbances including schizophrenia, depression, attention-deficit hyperactivity disorder and autism. Elevated maternal circulating stress hormones alter development of neural circuits in the fetal brain and cause long-term changes in behaviour. The aim of the present study was to investigate whether mild prenatal stress increases the vulnerability of dopamine neurons in adulthood. A low dose of 6-hydroxydopamine (6-OHDA, 5 µg/4 µl saline) was unilaterally infused into the medial forebrain bundle of nerve fibres in the rat brain in order to create a partial lesion of dopamine neurons which was sufficient to cause subtle behavioural deficits associated with early onset of Parkinson's disease without complete destruction of dopamine neurons. Voluntary exercise appeared to have a neuroprotective effect resulting in an improvement in motor control and decreased asymmetry in the use of left and right forelimbs to explore a novel environment as well as decreased asymmetry of tyrosine hydroxylase-positive cells in the substantia nigra pars compacta and decreased dopamine cell loss in 6-OHDA-lesioned rats. Prenatal stress appeared to enhance the toxic effect of 6-OHDA possibly by reducing the compensatory adaptations to exercise.
Syal, Supriya; Ipser, Jonathan; Phillips, Nicole; Thomas, Kevin G. F.; Honk, Jack; Stein, Dan J.
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Although animal evidence indicates that early life trauma results in pervasive hippocampal deficits underlying spatial and cognitive impairment, visuo-spatial data from adult humans with early childhood adversity are lacking. We administered 4 tests of visuo-spatial ability from the Cambridge Neuorpsychological Test Automated Battery (CANTAB) to adults with a history of childhood trauma (measured by the Childhood Trauma Questionnaire) and a matched sample of healthy controls (trauma/control = 27/28). We observed a significant effect of trauma history on spatial/pattern learning. These effects could not be accounted for by adverse adult experiences, and were sex-specific, with prior adversity improving performance in men but worsening performance in women, relative to controls. Limitations include the small sample size and reliance of our study design on a retrospective, self report measure. Our results suggest that early adversity can lead to specific and pervasive deficits in adult cognitive function.
Lamberts, Robert P.; Rietjens, Gerard J.; Tijdink, Hendrik H.; Noakes, Timothy D.; Lambert, Michael I.
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Recently a novel submaximal test, known as the Lamberts and Lambert submaximal cycle test (LSCT), has been developed with the purpose of monitoring and predicting changes in cycling performance. Although this test has been shown to be reliable and able to predict cycling performance, it is not known whether it can measure changes in training status. Therefore, the aim of this study was to determine whether the LSCT is able to track changes in performance parameters, and objective and subjective markers of well-being. A world class cyclo-cross athlete (31 years) volunteered to participate in a 10-week observational study. Before and after the study, a peak power output (PPO) test with respiratory gas analysis (VO2max) and a 40-km time trial (40-km TT) test were performed. Training data were recorded in a training logbook with a daily assessment of well-being, while a weekly LSCT was performed. After the training period all performance parameters had improved by a meaningful amount (PPO +5.2%; 40-km TT time −2.5%; VO2max +1.4%). Increased training loads during weeks 2 and 6 and the subsequent training-induced fatigue was reflected in the increased well-being scores. Changes during the LSCT were most clearly notable in (1) increased power during the first minute of third stage, (2) increased rating of perceived exertion during second and third stages, and (3) a faster heart rate recovery after the third stage. In conclusion, these data suggest that the LSCT is able to track changes in training status and detect the consequences of sharp increases in training loads which seem to be associated with accumulating fatigue.
Kaikkonen, Piia; Hynynen, Esa; Mann, Theresa; Rusko, Heikki; Nummela, Ari
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The overload principle of training states that training load (TL) must be sufficient to threaten the homeostasis of cells, tissues, organs, and/or body. However, there is no "golden standard" for TL measurement. The aim of this study was to examine if any post-exercise heart rate variability (HRV) indices could be used to evaluate TL in exercises with different intensities and durations. Thirteen endurance-trained males (35 ± 5 year) performed MODE (moderate intensity, 3 km at 60% of the maximal velocity of the graded maximal test (vVO2max)), HI (high intensity, 3 km at 85% vVO2max), and PRO (prolonged, 14 km at 60% vVO2max) exercises on a treadmill. HRV was analyzed with short-time Fourier-transform method during rest, exercise, and 15-min recovery. Rating of perceived exertion (RPE), blood lactate (BLa), and HFP120 (mean of 0–120 s post-exercise) described TL of these exercises similarly, being different for HI (P < 0.05) and PRO (P < 0.05) when compared with MODE. RPE and BLa also correlated negatively with HFP120 (r = −0.604, −0.401), LFP120 (−0.634, −0.601), and TP120 (−0.691, −0.569). HRV recovery dynamics were similar after each exercise, but the level of HRV was lower after HI than MODE. Increased intensity or duration of exercise decreased immediate HRV recovery, suggesting that post-exercise HRV may enable an objective evaluation of TL in field conditions. The first 2-min recovery seems to give enough information on HRV recovery for evaluating TL.
Stannard, L. M.; Himmelhoch, S.; Wynchank, S.
The envelopes of herpes simplex virus (HSV) particles are acquired from the inner nuclear membrane (INM) of the infected cell and virus-coded glycoproteins are present in the envelope of mature virions. Our ultrastructural study examined the process of virus envelopment and the targeting of two major viral glycoproteins, gB and gD, to the INM in HSV-infected human embryonic fibroblasts. It was shown that envelopment and transport of virus particles from the nucleus is facilitated by the formation of a dynamic tubulo-reticulum arising from the INM. Capsids were assembled in the nucleus and collected within INM tubules which protruded into the perinuclear space and thence into the cisternae of the endoplasmic reticulum (ER). Envelopment occurred by constriction and fusion of the tubular channel walls, releasing enveloped virions into the ER. Transport to the cell surface took place in membrane-bound compartments and probably followed the normal secretory pathway through the Golgi apparatus. Immunogold probes, tagged with specific monoclonal antibodies, were used to localize gB and gD during the process of virus maturation. Cytoplasmic membranes were not labelled, but probes bound inside the nucleus, mainly at sites of virus assembly. Labelling occurred on the nucleoplasmic side of the INM which surrounded capsids in the process of envelopment, but not on the outside of that membrane, although characteristic gB glycoprotein spikes were labelled on the envelopes of extracellular virus particles and on virions intrans-Golgi transport vesicles just prior to their release from the infected cell. gB was not detected on the surface of enveloped virions in the perinuclear space, or the cisternae of the ER orcis-Golgi, which suggests that the specific epitope was masked during that stage of intracellular processing. gD probes bound to virion envelopes and also to the tegument region of some particles found in both perinuclear and extracellular sites. We postulate that precursor core proteins for both gB and gD are transported first to the nucleus, and then, together with maturing capsids, are targeted to the INM, and later inserted into viral envelopes at the site of budding. Post-translational glycosylation of envelope proteins could occur as virus particles exit the nucleus and travel through the ER and Golgi compartments.
Shaboodien, Gasnat; Engel, Mark E; Syed, Faisal F; Poulton, Joanna; Badri, Motasim; Mayosi, Bongani M
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The mitochondrial DNA (mtDNA) T16189C polymorphism, with a homopolymeric C-tract of 10–12 cytosines, is a putative genetic risk factor for idiopathic dilated cardiomyopathy in the African and British populations. We hypothesized that this variant may predispose to dilated cardiomyopathy in people who are infected with the human immunodeficiency virus (HIV).
A case-control study of 30 HIV-positive cases with dilated cardiomyopathy and 37 HIV-positive controls without dilated cardiomyopathy was conducted. The study was confined to persons of black African ancestry to minimize confounding of results by population admixture. HIV-positive patients with an echocardiographically confirmed diagnosis of dilated cardiomyopathy and HIV-positive controls with echocardiographically normal hearts were studied. Patients with secondary causes of cardiomyopathy (such as hypertension, diabetes, pregnancy, alcoholism, valvular heart disease, and opportunistic infection) were excluded from the study. DNA samples were sequenced for the mtDNA T16189C polymorphism with a homopolymeric C-tract in the forward and reverse directions on an ABI3100 sequencer.
The cases and controls were well matched for age (median 35 years versus 34 years, P = 0.93), gender (males 60% vs 53%, P = 0.54), and stage of HIV disease (mean CD4 T cell count 260.7/μL vs. 176/μL, P = 0.21). The mtDNA T16189C variant with a homopolymeric C-tract was detected at a frequency of 26.7% (8/30) in the HIV-associated cardiomyopathy cases and 13.5% (5/37) in the HIV-positive controls. There was no significant difference between cases and controls (Odds Ratio 2.33, 95% Confidence Interval 0.67–8.06, p = 0.11).
The mtDNA T16189C variant with a homopolymeric C-tract is not associated with dilated cardiomyopathy in black African people infected with HIV.
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