Some aspects of temporal coding by single cochlear fibres from regions of cochlear hair cell degeneration in the guinea pig.
Some temporal coding properties of cochlear nerve fibers are investigated in kanamycin-treated guinea pigs (GPs) with various degrees of outer hair cell (OHC) degeneration. In particular, the phase locking ability of fibres from pathological cochleas, and also their adaptation properties are compared with the properties of normal cochlear fibres. No systematic effects of OHC loss on these properties have so far been found. These preliminary results therefore suggest (in so far as these animals can be regarded as models of sensorineural hearing loss of cochlear origin in man) that little deterioration should be expected in functions purely dependent upon faithful temporal coding of the stimulus waveform.


Neuronal polarity: remodeling microtubule organization.
Cell polarization generates morphological and functional asymmetry, and is crucial for the development and proper functioning of many cell types. Recent data have revealed that the microtubule cytoskeleton is a major determinant in the establishment and maintenance of neuronal polarity. Microtubules provide the structural basis for neuronal polarization, because of their intrinsic properties including inherent polarity. Moreover, the polarized microtubule network also forms the basis for selective cargo trafficking into axons and dendrites. Here we review recent studies examining the molecular processes that control microtubule remodeling and polarized cargo sorting, and propose that changes in microtubule organization play an instructive role in the initial polarization.


Spinal intradural extramedullary haemangioma: MRI and neurosurgical findings.
Haemangiomas, have rarely been encountered in the spinal intradural extramedullary space and the MRI findings of this entity have been described only in a few cases. We present the Magnetic Resonance Imaging (MRI) and surgical findings of a rare case of intradural extramedullary cavernous angioma located at the T1-T2 level in a 65-year-old man presented progressive paraparesis and upper thoracic back pain. On MRI, a well-circumscribed intradural solid mass, 1 cm in diameter, was detected and another enhancing nodular mass was found at the nerve roots of the cauda equina. The thoracic spinal lesion was removed and the histological diagnosis confirmed cavernous haemangioma. Although very uncommon, haemangioma should be included in the differential diagnosis when a spinal intradural extramedullary lesion is discovered and some neuroradiological findings could allow a presumptive diagnosis.


Oxidative and nitrosative responses of the chicken macrophage cell line MQ-NCSU to experimental Salmonella infection.
Phagocytes limit replication or kill ingested organisms by producing toxic reactive oxygen and nitrogen species via NADPH oxidase and inducible nitric oxide synthase (iNOS). The present experiments were to investigate the production and the possible roles of superoxide, hydrogen peroxide (H2O2) and nitric oxide (NO) in the MQ-NCSU chicken macrophage cell line infected with Salmonella in vitro. After infection, intracellular Salmonella viable counts remained constant until 24 h post infection (PI) and started to decline from 48 h PI. Infection of cells with S. Typhimurium, S. Enteritidis and S. Gallinarum, as well as exposure to S. Enteritidis LPS induced low, but significant concentrations of superoxide 1 to 2 h PI, as determined by reduction of ferricytochrome c. There was no difference in superoxide production in infected cells and control cells after 4 h. Increased H2O2 was observed from cells infected with all the different Salmonella species between 2 and 3 h of infection. Nitrite was always greater in infected cells compared to uninfected cells at all times. However, Salmonella was not completely eliminated from the cells though these cells are capable of eliciting a noticeable oxidative burst response and great nitrosative responses, indicating that a strong oxidative burst (and other mechanism/s) is essential for the elimination of intracellular Salmonella.


Ten steps for specifying saturation in qualitative research.
Saturation is critical to reliability of qualitative social sciences, but methods descriptions differ greatly in the degree of detail provided. Rigour could be improved by routinely following a ten-step methodological protocol. 1. Define the underlying disciplinary framework. 2. Specify the target class precisely. 3. Show how participants or cases were selected or excluded. 4. Describe techniques to minimise inadvertent or indirect selection bias. 5. Report homogeneity or heterogeneity of cases, relative to the focus of analysis. 6. Report processes for elicitation or extraction of information content. 7. Select code, meaning or model saturation. 8. Specify code and concept fineness or granularity. 9. Report order and randomisation of cases. 10. Define the level of precision in post facto tests of saturation.