query: Peer review process was corrupted

positive: Peer review Peer review is the evaluation of work by one or more people of similar competence to the producers of the work ( peers ) . It constitutes a form of self-regulation by qualified members of a profession within the relevant field . Peer review methods are employed to maintain standards of quality , improve performance , and provide credibility . In academia , scholarly peer review is often used to determine an academic paper 's suitability for publication . Peer review can be categorized by the type of activity and by the field or profession in which the activity occurs , e.g. , medical peer review .

negative: U.S. Government peer review policies Most federal regulatory agencies in the United States government must comply with specific peer review requirements before the agencies publicly disseminate certain scientific information . These requirements were published in a Peer Review Bulletin issued by the White House Office of Management and Budget ( OMB ) , which establishes `` government-wide standards concerning when peer review is required and , if required , what type of per review processes are appropriate . ''

negative: Peer critique Peer critique , a specialized form of critique , is the common practice of writers reviewing and providing constructive criticism of each other 's work . Most fiction writers use some form of peer critique as part of their process of writing .

negative: Peer jury process The peer jury process is often used in the arts to assess applications for grants , proposals for exhibitions made in response to an open call for submissions and art competitions . Like the practice of peer review used in the academic sphere , a peer jury brings to an evaluation process expertise that an organization or agency awarding grants or sponsoring a competition might not itself have .   A peer jury in the arts context is generally composed of artists selected to be representative of those working in a relevant discipline or area . While jurors are expected to have independence , anonymity is less of a concern than in academic peer review , in part because the jury 's task is not to catch errors or offer criticism but to only to select . For example , in Canada , agencies that award grants typically publish lists of jurors or make lists available on request .   In principle the peer jury process is an effective way for arts councils and other agencies to be responsive to and engaged with the constituencies they serve , and in touch with the latest developments in contemporary art .

negative: Graduate student journal A graduate student journal is an academic journal which is run by graduate students . These students are involved in the production , editing and peer review processes for the journal . On the whole , graduate student journals have a poor reputation , and limited funding and training can result in poor production values and editorial practices . Despite this , some graduate student journals , such as the Harvard Educational Review , are highly regarded , and peer review can be performed to a higher standard in student-run journals than in more mainstream journals .

negative: Retracted article on dopaminergic neurotoxicity of MDMA `` Severe dopaminergic neurotoxicity in primates after a common recreational dose regimen of MDMA3,4-methylenedioxy-N-methylamphetamine ( MDMA ) is the chemical name for the psychotropic drug commonly known as `` ecstasy '' . ( `` ecstasy '' ) '' , was a paper by Dr. George Ricaurte which was published in the leading journal Science , and later retracted . The reason was that instead of using MDMA , methamphetamine had been used in the test .   The retraction of the paper led to questions over its publication . It has also been asserted that this questions the peer review process .  Many have also argued that the failings in the paper ( use of materials other than those specified ) could not have been caught by peer review ; and that the scientific process did work successfully in the end , in that the article was ultimately retracted .   The paper was published in the 27 September 2002 issue of Science ( volume 297 , pages 2260-3 ) . The article had been submitted to Science on 29 May 2002 and was accepted for publication on 14 August 2002 . Neither the time required for peer review nor the time between acceptance for publication and actual date of publication were unusual .

negative: Molecular Endocrinology Molecular Endocrinology is a peer-reviewed journal that publishes research on the molecular processes of hormones .

negative: Information Processing and Management Information Processing and Management ( IPM ) is a peer-reviewed academic journal , published by Elsevier .

negative: Biology Direct Biology Direct is an online open access scientific journal that publishes original , peer-reviewed research papers , reviews , hypotheses , comments and discovery notes in biology . The journal is published by BioMed Central .   The journal follows a peer review system which is different from the traditional peer review system , which aims to give more responsibility to authors , and reduce sources of bias . Published articles include signed reviewer reports , and responses to the reports from the authors , to provide readers with an additional guide to the article .   Based on the information presented on their website : `` Biology Direct 's key aim is to provide authors and readers with an alternative to the traditional model of peer review . This includes making the author responsible for selecting potentially suitable reviewers for their manuscript , from the journal 's Editorial Board ; making the peer review process open rather than anonymous ; and making the reviewers ' reports public , thus increasing the responsibility of the referees and eliminating sources of abuse in the refereeing process . ''

negative: Molecular Biology Reports Molecular Biology Reports is a monthly peer-reviewed scientific journal covering research on normal and pathological molecular processes .

negative: Nonlinear Processes in Geophysics Nonlinear Processes in Geophysics is an open-access peer-reviewed scientific journal publishing research within Earth science .

negative: Journal of Food Processing and Preservation The Journal of Food Processing and Preservation is a peer-reviewed scientific journal that covers research into food processing and preservation . It is published by Wiley-Blackwell . The journal moved to online-only publication in 2011 .

negative: Stochastic Processes and their Applications Stochastic Processes and their Applications is a monthly peer-reviewed scientific journal published by Elsevier for the Bernoulli Society for Mathematical Statistics and Probability . The editor-in-chief is H. Dehling . The principal focus of this journal is theory and applications of stochastic processes . It was established in 1973 .

negative: Geoscientific Model Development Geoscientific Model Development is a peer-reviewed open access scientific journal published by Copernicus Publications on behalf of the European Geosciences Union . It covers the description , development , and evaluation of numerical models of the Earth system and its components .   The journal has a two-stage publication process . In the first stage , papers that pass a rapid access peer-review are immediately published on the Geoscientific Model Development Discussions website . They are then subject to interactive public discussion , during which the referees ' comments ( anonymous or attributed ) , additional short comments by other members of the scientific community ( attributed ) , and the authors ' replies are published . In the second stage , the peer-review process is completed and , if accepted , the final revised papers are published in Geoscientific Model Development .

negative: Replication crisis The replication crisis ( or replicability crisis ) refers to a methodological crisis in science in which scientists have found that the results of many scientific experiments are difficult or impossible to replicate on subsequent investigation , either by independent researchers or by the original researchers themselves . While the crisis has long-standing roots , the phrase was coined in the early 2010s as part of a growing awareness of the problem .   Since the reproducibility of experiments is an essential part of the scientific method , the inability to replicate the studies of others has potentially grave consequences for many fields of science in which significant theories are grounded on unreproduceable experimental work .   The replication crisis has been particularly widely discussed in the field of psychology ( and in particular , social psychology ) and in medicine , where a number of efforts have been made to re-investigate classic results , and to attempt to determine both the validity of the results , and , if invalid , the reasons for the failure of replication .

negative: Institutional review board An institutional review board ( IRB ) , also known as an ` independent ethics committee ' ( ` IEC ' ) , ` ethical review board ' ( ` ERB ' ) , or ` research ethics board ' ( ` REB ' ) , is a type of committee used in research in the United States that has been formally designated to approve , monitor , and review biomedical and behavioral research involving humans . They often conduct some form of risk-benefit analysis in an attempt to determine whether or not research should be completed . The purpose of the IRB is to assure that appropriate steps are taken to protect the rights and welfare of humans participating as subjects in a research study .

negative: Applied Microbiology and Biotechnology The Applied Microbiology and Biotechnology is a peer-reviewed biweekly journal publishes papers and mini-reviews of new and emerging products , processes and technologies in the area of prokaryotic or eukaryotic cells , relevant enzymes and proteins ; applied genetics and molecular biotechnology ; genomics and proteomics ; applied microbial and cell physiology ; environmental biotechnology ; process and products and more .

negative: Clinical Laboratory Improvement Act, 1988 Clinical Laboratory Improvement Act of 1988 ( CLIA 88 ) was passed in the USA subsequent to the publication of an article in November 1987 in the Wall Street Journal entitled `` Lax Laboratories : The Pap Test Misses Much Cervical Cancer Through Labs Errors '' , which alerted the public to the fact that a pap smear may be falsely negative . The article implied that false negative tests resulted largely from the carelessness of doctors . Subsequent to this , claims involving pap smears showed an alarming growth . The Act aimed at a comprehensive regulation of gynecologic cytology laboratories .

negative: Center for Scientific Review The Center for Scientific Review ( CSR ) is the portal for United States National Institutes of Health ( NIH ) grant applications and their review for scientific merit . The CSR organizes the peer review groups or study sections that evaluate the majority ( 70 % ) of the research grant applications sent to NIH . It also receives all grant applications for NIH , as well as for some other components of the United States Department of Health and Human Services ( DHHS ) . Since 1946 , its mission has remained clear and timely : to see that NIH grant applications receive fair , independent , expert , and timely reviews -- free from inappropriate influences -- so NIH can fund the most promising research .   CSR receives nearly 80,000 applications a year and recruits over 18,000 external experts to review its portion of them in its study sections , which often meet three times during the year . Additional scientists serve on other NIH advisory councils , which provide a second level of peer review and make funding recommendations based on priorities set by the United States Congress , DHHS , and the public .

negative: Regulatory Toxicology and Pharmacology Regulatory Toxicology and Pharmacology is a monthly peer-reviewed scientific journal which covers legal aspects of toxicological and pharmacological regulations . It is published by Elsevier on behalf of the International Society of Regulatory Toxicology & Pharmacology . The current editor-in-chief is Gio Batta Gori . The journal is financed in part by the tobacco , pharmaceutical , and chemical industries .   In 2002 , a group of 45 academics wrote a letter accusing the journal of a concealed pro-industry bias , saying that it `` reads like an industry trade publication , but it 's masked as a peer-reviewed journal '' and that it lacked any `` credible peer-review process '' . The scientists criticized the journal for failing to disclose conflicts of interest on the part of article authors and editors , citing a case in which Gori was paid $ 30,000 by the Tobacco Institute to publish an article in the journal dismissing the health risks of secondhand smoke .   The journal has been accused of being `` broker of junk science '' by the Center for Public Integrity .

negative: African Peer Review Mechanism The African Peer Review Mechanism ( APRM ) is a mutually agreed instrument voluntarily acceded to by the member states of the African Union ( AU ) as a self-monitoring mechanism . It was founded in 2003 .   The mandate of the APRM is to encourage conformity in regard to political , economic and corporate governance values , codes and standards , among African countries and the objectives in socio-economic development within the New Partnership for Africa 's Development .

negative: Nature Methods Nature Methods is a monthly peer-reviewed scientific journal covering new scientific techniques . It was established in 2004 and is published by the Nature Publishing Group . Like other Nature journals , there is no external editorial board and editorial decisions are made by an in-house team , although peer review by external experts forms a part of the review process .   According to the Journal Citation Reports , the journal had a 2015 impact factor of 25.328 , ranking it first in the category `` Biochemical Research Methods '' .

negative: Review of Market Integration Review of Market Integration is a peer-reviewed journals that provides a forum to discuss issues related to market integration as part of the developmental process of emerging economies .   It is published three times in a year by SAGE Publications in association with Foundation .

negative: Journal of Food Process Engineering The Journal of Food Process Engineering is a peer-reviewed scientific journal that covers research on applications of engineering to food and food processing . It was established in 1977 and is published by Wiley-Blackwell . The journal moved to online-only publication in 2011 .

negative: Software inspection Inspection in software engineering , refers to peer review of any work product by trained individuals who look for defects using a well defined process . An inspection might also be referred to as a Fagan inspection after Michael Fagan , the creator of a very popular software inspection process .

negative: Independent reviewer The US Food and Drug Administration requires that developers of medical device follow a system of design controls . A key part of this system is design review , defined in 21CFR820 .3 section ( h ) as `` a documented , comprehensive , systematic examination of the design to evaluate the adequacy of the design requirements , to evaluate the capability of the design to meet these requirements , and to identify problems . ''   In 21CFR820 .30 section ( e ) , it is stated that an independent reviewer is required for any design review . An independent reviewer is an individual who does not have direct professional responsibility for the design stage under review , assuring an independent and objective review . Within the context of formal design reviews , the practical solution is simply to ensure a fresh perspective , based on the principle that those who are too close to the design may overlook design errors . Thus , reviewers should not have been significantly involved in the activities under review .

negative: Scientific misconduct Scientific misconduct is the violation of the standard codes of scholarly conduct and ethical behavior in professional scientific research . A Lancet review on Handling of Scientific Misconduct in Scandinavian countries provides the following sample definitions : ( reproduced in The COPE report 1999 . )  Danish definition : `` Intention or gross negligence leading to fabrication of the scientific message or a false credit or emphasis given to a scientist ''  Swedish definition : `` Intention -LSB- al -RSB- distortion of the research process by fabrication of data , text , hypothesis , or methods from another researcher 's manuscript form or publication ; or distortion of the research process in other ways . ''   The consequences of scientific misconduct can be damaging for both perpetrators and any individual who exposes it . In addition there are public health implications attached to the promotion of medical or other interventions based on dubious research findings .

negative: Digital Signal Processing (journal) Digital Signal Processing is a monthly peer-reviewed open access scientific journal covering all areas of signal processing . It as established in 1991 and published by Academic Press , now Elsevier . The editor-in-chief is Ercan E. Kuruoglu ( ISTI-CNR , Pisa , Italy ) .

negative: Panetta Review The Panetta Review was a secret internal review conducted by Leon Panetta , then the Director of the United States Central Intelligence Agency , of the CIA 's torture of detainees during the administration of George W. Bush . The review led to a series of memoranda that , as of March 2014 , remained classified . According to The New York Times , the memoranda `` cast a particularly harsh light '' on the Bush-era interrogation program , and people who have read them have said parts of the memos are `` particularly scorching '' of techniques such as waterboarding , which the memos describe as providing little valuable intelligence .   The existence of the review was revealed by Sen. Mark Udall ( D-CO ) during a hearing of the Senate Intelligence Committee on December 17 , 2013 . Udall said that the report was consistent with a highly critical report generated by the Intelligence Committee and conflicted with the CIA 's official response .   A 525-page summary of the Senate Intelligence Committee 's report was made public on December 9 , 2014 .

negative: PubPeer PubPeer is a website that allows users to discuss and review scientific research .   The site is one of many allowing academics to engage in post-publication peer review , and has highlighted shortcomings in several high-profile papers , in some cases leading to retractions and to accusations of scientific fraud ,  as noted by Retraction Watch .   Accusations of libel have been levelled at some of PubPeer 's users ; correspondingly PubPeer comments are required to use only facts that can be publicly verified .

negative: Scientific Integrity in Policymaking `` Scientific Integrity in Policymaking : An Investigation into the Bush Administration 's Misuse of Science '' is the title of a report published by the Union of Concerned Scientists in February , 2004 . The report was the culmination of an investigation of the Bush administration 's objectivity in science , and ultimately a criticism thereof . ( After it was published , the report 's existence was fairly well-publicized by the United States ' mass media . )

negative: ExOrdo Ex Ordo is an abstract and paper management system for research or academic conference and symposia . Their web application automates the process of collecting and peer reviewing abstracts and papers . The tool is cloud-based , offering an online platform to allow all the persons involved in the conference to get involved directly .  The conference management system uses an built-in intelligence , creating automated tasks for each user involved in a conference -- organisers , authors and reviewers -- to guide them through the process of submitting , reviewing and accepting papers and abstracts .

negative: Information Processing Letters Information Processing Letters is a peer reviewed scientific journal in the field of computer science , published by Elsevier . The aim of the journal is to enable fast dissemination of results in the field of information processing in the form of short papers . Submissions are limited to nine double-spaced pages . Both theoretical and experimental research is covered .


query: But more than 7% of deaths are related to cold—counting hypothermia, as well as increased blood pressure and risk of heart attack that results when the body restricts blood flow in response to frigid temperatures.”

positive: Drowning Drowning is defined as respiratory impairment from being in or under a liquid . It is further classified by outcome into : death , ongoing health problems , and no ongoing health problems . Drowning itself is quick and silent , although it may be preceded by distress which is more visible .   Generally , in the early stages of drowning , very little water enters the lungs : a small amount of water entering the trachea causes a muscular spasm that seals the airway and prevents the passage of both air and water until unconsciousness occurs . This means a person drowning is unable to shout or call for help , or seek attention , as they can not obtain enough air . The instinctive drowning response is the final set of autonomic reactions in the 20 -- 60 seconds before sinking underwater , and to the untrained eye can look similar to calm safe behavior . Lifeguards and other persons trained in rescue learn to recognize drowning people by watching for these movements . If the process is not interrupted , loss of consciousness due to hypoxia is followed rapidly by cardiac arrest . At this stage , the process is still usually reversible by prompt and effective rescue and first aid . Survival rates depend strongly on the duration of immersion .   In 2013 , there were about 1.7 million cases of drowning . Unintentional drowning is the third leading cause of unintentional injury resulting in death worldwide . In 2013 , it was estimated to have resulted in 368,000 deaths , down from 545,000 deaths in 1990 . Of these deaths , 82,000 occurred in children less than five years old . It accounts for 7 % of all injury related deaths ( excluding those due to natural disasters ) , with 91 % of these deaths occurring in low-income and middle-income countries . Drowning occurs more frequently in males and the young . The rate of drowning in populations around the world varies widely according to their access to water , the climate and the national swimming culture .  Most drownings are preventable .

positive: Hypothermia Hypothermia is reduced body temperature that happens when a body dissipates more heat than it absorbs . In humans , it is defined as a body core temperature below 35.0 C. Symptoms depend on the temperature . In mild hypothermia there is shivering and mental confusion . In moderate hypothermia shivering stops and confusion increases . In severe hypothermia there may be paradoxical undressing , in which a person removes his or her clothing , as well as an increased risk of the heart stopping .   Hypothermia has two main types of causes . It classically occurs from exposure to extreme cold . It may also occur from any condition that decreases heat production or increases heat loss . Commonly this includes alcohol intoxication but may also include low blood sugar , anorexia , and advanced age , among others . Body temperature is usually maintained near a constant level of 36.5 -- through thermoregulation . Efforts to increase body temperature involve shivering , increased voluntary activity , and putting on warmer clothing . Hypothermia may be diagnosed based on either a person 's symptoms in the presence of risk factors or by measuring a person 's core temperature .   The treatment of mild hypothermia involves warm drinks , warm clothing and physical activity . In those with moderate hypothermia heating blankets and warmed intravenous fluids are recommended . People with moderate or severe hypothermia should be moved gently . In severe hypothermia extracorporeal membrane oxygenation ( ECMO ) or cardiopulmonary bypass may be useful . In those without a pulse cardiopulmonary resuscitation ( CPR ) is indicated along with the above measures . Rewarming is typically continued until a person 's temperature is greater than 32 C . If there is no improvement at this point or the blood potassium level is greater than 12 mmol/liter at any time resuscitation may be discontinued .   Hypothermia is the cause of at least 1500 deaths a year in the United States . It is more common in older people and males . One of the lowest documented body temperatures from which someone with accidental hypothermia has survived is 13.0 C in a near-drowning of a 7-year-old girl in Sweden . Survival after more than six hours of CPR has been described . In those in whom ECMO or bypass is used survival is around 50 % . Deaths due to hypothermia have played an important role in many wars . The term is from Greek ὑπο , ypo , meaning `` under '' , and θερμία , thermía , meaning `` heat '' . The opposite of hypothermia is hyperthermia , an increased body temperature due to failed thermoregulation .

positive: Underwater diving Underwater diving is the practice of descending below the water 's surface to conduct underwater activities . In ambient pressure diving , the diver is exposed to the pressure of the surrounding water , and uses breathing apparatus for scuba diving or surface supplied diving , or when freediving , will breath-hold . The saturation diving technique reduces the risk of decompression sickness after long duration deep dives . Atmospheric diving suits may be used to isolate the diver from the effects of high ambient pressure . Although not usually considered to be diving , crewed submersibles can extend depth range , while remotely controlled or robotic diving machines can reduce the risk to human divers .   The diving environment exposes the diver to a wide range of hazards , and though the risks are largely controlled by appropriate diving skills , training , types of equipment and breathing gases used depending on the mode , depth and purpose of diving , it remains a relatively dangerous activity . Diving activities are restricted to relatively shallow depths ranging from around 40 m ( 130 ft. ) maximum for recreational Scuba diving to commercial saturation diving maximum around 534 metres ( 1,752 ft ) and 610 metres ( 2,000 ft ) wearing atmospheric diving suits . Diving is also restricted to conditions which are not excessively hazardous , though the level of risk acceptable to the diver can vary considerably . Occasionally diving may be done in liquids other than water .   Recreational diving , sometimes called sport diving or subaquatics , is a popular leisure activity . Technical diving is a form of recreational diving that achieves greater depths or endurance in more challenging conditions . Professional diving ( commercial diving , diving for scientific research purposes or diving for financial gain ) takes a range of diving activities to the underwater work site . Public safety diving is the underwater work done by law enforcement , fire rescue , and search & rescue/recovery dive teams , and may be done by professionals or volunteers . Military diving includes combat diving , clearance diving and ship 's husbandry diving . Underwater sports is a group of competitive sports using either free-diving , snorkeling or scuba technique , or a combination of these techniques . The term `` deep sea diving '' refers to underwater diving , usually with surface supplied equipment , and often refers specifically to the use of standard diving dress with the traditional copper helmet . `` Hard hat '' diving is any form of diving with a helmet , including the standard copper helmet , and other forms of free-flow and lightweight demand helmets .

positive: Cardiovascular disease Cardiovascular disease ( CVD ) is a class of diseases that involve the heart or blood vessels . Cardiovascular disease includes coronary artery diseases ( CAD ) such as angina and myocardial infarction ( commonly known as a heart attack ) . Other CVDs include stroke , heart failure , hypertensive heart disease , rheumatic heart disease , cardiomyopathy , heart arrhythmia , congenital heart disease , valvular heart disease , carditis , aortic aneurysms , peripheral artery disease , thromboembolic disease , and venous thrombosis .   The underlying mechanisms vary depending on the disease in question . Coronary artery disease , stroke , and peripheral artery disease involve atherosclerosis . This may be caused by high blood pressure , smoking , diabetes , lack of exercise , obesity , high blood cholesterol , poor diet , and excessive alcohol consumption , among others . High blood pressure results in 13 % of CVD deaths , while tobacco results in 9 % , diabetes 6 % , lack of exercise 6 % and obesity 5 % . Rheumatic heart disease may follow untreated strep throat .   It is estimated that 90 % of CVD is preventable . Prevention of atherosclerosis involves improving risk factors through : healthy eating , exercise , avoidance of tobacco smoke and limiting alcohol intake . Treating risk factors , such as high blood pressure , blood lipids and diabetes is also beneficial . Treating people who have strep throat with antibiotics can decrease the risk of rheumatic heart disease . The effect of the use of aspirin in people who are otherwise healthy is of unclear benefit .   Cardiovascular diseases are the leading cause of death globally . This is true in all areas of the world except Africa . Together they resulted in 17.9 million deaths ( 32.1 % ) in 2015 up from 12.3 million ( 25.8 % ) in 1990 . Deaths , at a given age , from CVD are more common and have been increasing in much of the developing world , while rates have declined in most of the developed world since the 1970s . Coronary artery disease and stroke account for 80 % of CVD deaths in males and 75 % of CVD deaths in females . Most cardiovascular disease affects older adults . In the United States 11 % of people between 20 and 40 have CVD , while 37 % between 40 and 60 , 71 % of people between 60 and 80 , and 85 % of people over 80 have CVD . The average age of death from coronary artery disease in the developed world is around 80 while it is around 68 in the developing world . Disease onset is typically seven to ten years earlier in men as compared to women .

positive: Shock (circulatory) Circulatory shock , commonly known as shock , is a life-threatening medical condition of low blood perfusion to tissues resulting in cellular injury and inadequate tissue function . The typical signs of shock are low blood pressure , rapid heart rate , signs of poor end-organ perfusion ( i.e. : low urine output , confusion , or loss of consciousness ) , and weak pulses .   The shock index ( SI ) , defined as heart rate divided by systolic blood pressure , is an accurate diagnostic measure that is more useful than hypotension and tachycardia in isolation . Under normal conditions , a number between 0.5 and 0.8 is typically seen . Should that number increase , so does suspicion of an underlying state of shock . Blood pressure alone may not be a reliable sign for shock , as there are times when a person is in circulatory shock but has a stable blood pressure .   Circulatory shock is not related to the emotional state of shock . Circulatory shock is a life-threatening medical emergency and one of the most common causes of death for critically ill people . Shock can have a variety of effects , all with similar outcomes , but all relate to a problem with the body 's circulatory system . For example , shock may lead to hypoxemia ( a lack of oxygen in arterial blood ) or cardiac and/or respiratory arrest .   One of the key dangers of shock is that it progresses by a positive feedback mechanism . Poor blood supply leads to cellular damage , which results in an inflammatory response to increase blood flow to the affected area . This is normally very useful to match up supply with tissue demand for nutrients . However , if enough tissue causes this , it will deprive vital nutrients from other parts of the body . Additionally , the ability of the circulatory system to meet this increase in demand causes saturation , a major result of which is that other parts of the body begin to respond in a similar way , thus exacerbating the problem . Due to this chain of events , immediate treatment of shock is critical to survival .

negative: Butterflies in the stomach Butterflies in the stomach is the physical sensation in humans of a `` fluttery '' feeling in the stomach , caused by a reduction of blood flow to the organ . This is as a result of the release of adrenaline in the fight-or-flight response , which causes increased heart rate and blood pressure , consequently sending more blood to the muscles .   It is a sign of social anxiety disorder .

negative: Bayliss effect Bayliss effect or Bayliss myogenic response is a special manifestation of the myogenic tone in the vasculature . The Bayliss effect in vascular smooth muscles cells is a response to stretch . This is especially relevant in arterioles of the body . When blood pressure is increased in the blood vessels and the blood vessels distend , they react with a constriction ; this is the Bayliss effect . Stretch of the muscle membrane opens a stretch-activated ion channel . The cells then become depolarized and this results in a Ca2 + signal and triggers muscle contraction . It is important to understand that no action potential is necessary here ; the level of entered calcium affects the level of contraction proportionally and causes tonic contraction . The contracted state of the smooth muscle depends on the grade of stretch and plays an important part in the regulation of blood flow .   Increased contraction increases the total peripheral resistance ( TPR ) and this further increases the mean arterial pressure ( MAP ) . This is explained by the following equation :  where CO is the cardiac output which is the volume of blood pumped by the heart in one minute .   This effect is independent of nervous mechanisms and that is how we differentiate it from the myogenic tone , which is controlled by the sympathetic nervous system .   The overall effect of the myogenic response ( Bayliss effect ) is to decrease blood flow across a vessel after an increase in blood pressure .

negative: Baroreflex The baroreflex or baroreceptor reflex is one of the body 's homeostatic mechanisms that helps to maintain blood pressure at nearly constant levels . The baroreflex provides a rapid negative feedback loop in which an elevated blood pressure reflexively causes the heart rate to decrease and also causes blood pressure to decrease . Decreased blood pressure decreases baroreflex activation and causes heart rate to increase and to restore blood pressure levels . The baroreflex can begin to act in less than the duration of a cardiac cycle ( fractions of a second ) and thus baroreflex adjustments are key factors in dealing with postural hypotension , the tendency for blood pressure to decrease on standing due to gravity .   The system relies on specialized neurons , known as baroreceptors , in the aortic arch , carotid sinuses , and elsewhere to monitor changes in blood pressure and relay them to the Medulla . Baroreceptors are stretch receptors and respond to the pressure induced stretching of the blood vessel in which they are found . Baroreflex induced changes in blood pressure are mediated by both branches of the autonomic nervous system -- that is the parasympathetic and sympathetic nerves . Baroreceptors are active even at normal blood pressures so that their activity informs the brain about both increases and decreases in blood pressure .   The body contains two other , slower acting systems to regulate blood pressure : the heart releases atrial natriuretic peptide when blood pressure is too high , and the kidneys sense and correct low blood pressure with the renin-angiotensin system .

negative: High pressure receptor zones In physiology high pressure receptor zones are the places baroreceptors are found within the aortic arch and carotid sinus . They are only sensitive to blood pressures above 60 mmHg .   When these receptors are activated they elicit a depressor response ; which decreases the heart rate and causes a general vasodilation . An increase in arterial blood pressure reflexly elicits an increase in vagal neuronal activity to the heart ( i.e. the resulting decreased heart rate ) .   The afferent nerves from the baroreceptors are called buffer nerves .

negative: Medullary ischemic reflex The medullary ischemic reflex is a big response to a drop in blood pressure in the brain particularly in the medulla , where the lack of oxygen due to decreased perfusion triggers an autonomic response from the cardiac and vasomotor centers . The cardiac and vasomotor centers respond to the decrease in blood pressure with sympathetic outflow to the heart and blood vessels . This outflow causes increased heart rate and force of contraction , as well as bodywide vasoconstriction . Together these responses increase blood pressure and perfusion rate to the brain , ending the feedback loop .

negative: Hemodynamics Hemodynamics or hæmodynamics is the dynamics of blood flow . The circulatory system is controlled by homeostatic mechanisms , much as hydraulic circuits are controlled by control systems . Hemodynamic response continuously monitors and adjusts to conditions in the body and its environment . Thus hemodynamics explains the physical laws that govern the flow of blood in the blood vessels .   Blood flow ensures the transportation of nutrients , hormones , metabolic wastes , O2 and CO2 throughout the body to maintain cell-level metabolism , the regulation of the pH , osmotic pressure and temperature of the whole body , and the protection from microbial and mechanical harms .   Blood is a non-Newtonian fluid , best studied using rheology rather than hydrodynamics . Blood vessels are not rigid tubes , so classic hydrodynamics and fluids mechanics based on the use of classical viscometers are not capable of explaining hemodynamics .

negative: Surface Chemistry of Microvasculature Microvasculature is defined as vessels ( venules or capillaries ) with a maximum average diameter of 0.3 millimeters . As the vessels decrease in size , they increase their surface-area-to-volume ratio . This allows surface properties to play a significant role in the function of the vessel .   Diffusion occurs through the walls of the vessels due to a concentration gradient , allowing the necessary exchange of ions , molecules , or blood cells . The permeability of a capillary wall is determined by the type of capillary and the surface of the endothelial cells . A continuous , tightly spaced endothelial cell lining only permits the diffusion of small molecules . Larger molecules and blood cells require adequate space between cells or holes in the lining . The high resistivity of a cellular membrane prevents the diffusion of ions without a membrane transport protein . The hydrophobicity of an endothelial cell surface determines whether water or lipophilic molecules will diffuse through the capillary lining . The blood brain barrier restricts diffusion to small hydrophobic molecules , making drug diffusion difficult to achieve .   Blood flow is directly influenced by the thermodynamics of the body . Changes in temperature affect the viscosity and surface tension of the blood , altering the minimum blood flow rate . At high temperatures the minimum flow rate will decrease and the capillary will expand . This allows heat transfer through the increased surface area of the inner capillary lining and through increased blood flow . At low temperatures the minimum flow rate will increase and the capillary will constrict . This restricts blood flow and decreases the surface area of the capillary , reducing heat transfer .   Fluid mechanics are primarily affected by pressure , temperature , heat transfer , and electrokinetics . An increase in pressure increases the flow rate given by the Starling equation . An increase in temperature increases the wettability of the surface , promoting fluid flow . Heat also decreases the viscosity of the lumen . Heat transfer is monitored by thermoreceptors which regulate the amount of capillary beds open for heat dissipation . The surface chemistry of the endothelial cell lining also dictates fluid flow . A charged surface will acquire a layer of stagnant diffuse ions that hinder the flow of ions in the lumen . This decreases the lumen velocity and promotes the exchange of molecules through the capillary lining .

negative: Coronary artery ectasia Coronary artery ectasia is a rare disease that occurs in only 0.3-4 .9 % of people in North America . Coronary artery ectasia is characterized by the enlargement of a coronary artery to 1.5 times or more than its normal diameter . The disease is commonly asymptomatic and is normally discovered when performing tests for other conditions such as coronary artery disease , stable angina and other acute coronary syndromes . Coronary artery ectasia occurs 4 times more frequently in males than in females and in people who have risk factors for heart disease such as smokers . While the disease is commonly found in patients with atherosclerosis and coronary artery disease , it can occur by itself and in both cases it can cause health problems . The disease can cause the heart tissue to be deprived of blood and die due to decreased blood flow , and blockages due to blood clots or spasms of the blood vessel . This blood flow disruption can cause permanent damage to the muscle if the deprivation is prolonged . Coronary artery ectasia also increases the chance of developing large weak spots in the affected coronary arteries , or aneurysms that can rupture and result in death . The damage can result in angina which is pain in the chest and is a common complaint in these patients .

negative: Coronary thrombosis Coronary thrombosis is the formation of a blood clot inside a blood vessel of the heart . This blood clot restricts blood flow within the heart . It is associated with narrowing of blood vessels subsequent to clotting . The condition is considered as a type of ischaemic heart disease , also known as a heart attack or myocardial infarction .   Thrombosis in the heart can lead to a myocardial infarction . Coronary thrombosis and myocardial infarction are sometimes used as synonyms , although this is technically inaccurate as the thrombosis refers to the blocking of blood vessels , while the infarction refers to the tissue death due to the consequent loss of blood flow to the heart tissue . The heart contains many connecting blood vessels , and depending upon the location of the thrombosis , the infarction may cause no symptoms . Coronary thrombosis is caused by atherosclerosis.This is when there is build up of cholesterol and fats in the artery walls . So the blood will clot because there is n't enough room for it to flow . The main causes of coronary thrombosis are stress , smoking , high blood pressure , and lack of exercise . Symptoms are sharp pains around the chest area , breathing difficulties , dizziness , and fainting . This is treated by taking Aspirin , Nitrates , or Beta Blockers .   Coronary thrombosis can be a complication associated with drug-eluting stents .

negative: Pulsus paradoxus Pulsus paradoxus ( PP ) , also paradoxic pulse or paradoxical pulse , is an abnormally large decrease in systolic blood pressure and pulse wave amplitude during inspiration . The normal fall in pressure is less than 10 mmHg . When the drop is more than 10 mmHg , it is referred to as pulsus paradoxus . Pulsus paradoxus is not related to pulse rate or heart rate and it is not a paradoxical rise in systolic pressure . The normal variation of blood pressure during breathing/respiration is a decline in blood pressure during inhalation and an increase during exhalation . Pulsus paradoxus is a sign that is indicative of several conditions , including cardiac tamponade , constrictive pericarditis , chronic sleep apnea , croup , and obstructive lung disease ( e.g. asthma , COPD ) .   The paradox in pulsus paradoxus is that , on clinical examination , one can detect beats on cardiac auscultation during inspiration that can not be palpated at the radial pulse . It results from an accentuated decrease of the blood pressure , which leads to the ( radial ) pulse not being palpable and may be accompanied by an increase in the jugular venous pressure height ( Kussmaul 's sign ) . As is usual with inspiration , the heart rate is slightly increased , due to decreased left ventricular output .

negative: Sepsis Sepsis is a life-threatening condition that arises when the body 's response to infection causes injury to its own tissues and organs . Common signs and symptoms include fever , increased heart rate , increased breathing rate , and confusion . There also may be symptoms related to a specific infection , such as a cough with pneumonia , or painful urination with a kidney infection . In the very young , old , and people with a weakened immune system , there may be no symptoms of a specific infection and the body temperature may be low or normal , rather than high . Severe sepsis is sepsis causing poor organ function or insufficient blood flow . Insufficient blood flow may be evident by low blood pressure , high blood lactate , or low urine output . Septic shock is low blood pressure due to sepsis that does not improve after reasonable amounts of intravenous fluids are given .   Sepsis is caused by an immune response triggered by an infection . Most commonly , the infection is bacterial , but it may also be from fungi , viruses , or parasites . Common locations for the primary infection include lungs , brain , urinary tract , skin , and abdominal organs . Risk factors include young or old age , a weakened immune system from conditions such as cancer or diabetes , major trauma , or burns . An older method of diagnosis was based on meeting at least two systemic inflammatory response syndrome ( SIRS ) criteria due to a presumed infection . In 2016 , SIRS was replaced with qSOFA which is two of the following three : increased breathing rate , change in level of consciousness , and low blood pressure . Blood cultures are recommended preferably before antibiotics are started , however , infection of the blood is not required for the diagnosis . Medical imaging should be used to look for the possible location of infection . Other potential causes of similar signs and symptoms include anaphylaxis , adrenal insufficiency , low blood volume , heart failure , and pulmonary embolism , among others .   Sepsis usually is treated with intravenous fluids and antibiotics . Typically , antibiotics are given as soon as possible . Often , ongoing care is performed in an intensive care unit . If fluid replacement is not enough to maintain blood pressure , medications that raise blood pressure may be used . Mechanical ventilation and dialysis may be needed to support the function of the lungs and kidneys , respectively . To guide treatment , a central venous catheter and an arterial catheter may be placed for access to the bloodstream . Other measurements such as cardiac output and superior vena cava oxygen saturation may be used . People with sepsis need preventive measures for deep vein thrombosis , stress ulcers and pressure ulcers , unless other conditions prevent such interventions . Some might benefit from tight control of blood sugar levels with insulin . The use of corticosteroids is controversial . Activated drotrecogin alfa , originally marketed for severe sepsis , has not been found to be helpful , and was withdrawn from sale in 2011 .   Disease severity partly determines the outcome . The risk of death from sepsis is as high as 30 % , from severe sepsis as high as 50 % , and from septic shock as high as 80 % . The number of cases worldwide is unknown as there is little data from the developing world . Estimates suggest sepsis affects millions of people a year . In the developed world approximately 0.2 to 3 people per 1000 are affected by sepsis yearly , resulting in about a million cases per year in the United States . Rates of disease have been increasing . Sepsis is more common among males than females . The medical condition has been described since the time of Hippocrates . Septicemia and blood poisoning are terms that referred to the microorganisms or their toxins in the blood and are no longer commonly used .

negative: Heart failure cell Heart failure cells are siderophages ( hemosiderin-containing macrophages ) generated in the alveoli of patients with left heart failure or chronic pulmonary edema , when the high pulmonary blood pressure causes red cells to pass through the vascular wall . Siderophages are not specific of heart failure . They are present wherever red blood cells encounter macrophages .   In left heart failure , the left ventricle can not keep pace with the incoming blood from the pulmonary veins . The resulting backup causes increased pressure on the alveolar capillaries , and red blood cells leak out . Alveolar macrophages ( dust cells ) engulf the red blood cells , and become engorged with brownish hemosiderin .   In chronic pulmonary edema , alveolar septa become thick and fibrous , again increasing pressure on alveolar capillaries and resulting in leakage of red blood cells which undergo phagocytosis by alveolar macrophages .

negative: Cardiovascular centre The cardiovascular centre is a part of the human brain responsible for the regulation of the rate at which the heart beats through the nervous and endocrine systems . It is found in the medulla oblongata . Normally , the heart beats without nervous control , but in some situations ( e.g. , exercise , body trauma ) , the cardiovascular centre is responsible for altering the rate at which the heart beats . It also mediates respiratory sinus arrhythmia .   When a change of blood pH is detected by central chemoreceptors or a change of blood pressure is detected by peripheral chemoreceptors in aortic bodies and in carotid bodies , the cardiovascular centre affects changes to the heart rate by sending a nerve impulse to the cardiac pacemaker ( or SA node ) via sympathetic fibres ( to cause faster and stronger cardiac muscle contraction ) and the vagus nerve ( to cause slower and less strong cardiac muscle contraction ) . The cardiovascular centre also increases the stroke volume of the heart ( that is , the amount of blood it pumps ) . These two changes help to regulate the cardiac output , so that a sufficient amount of blood reaches tissue .   Hormones like epinephrine and norepinephrine can affect the cardiovascular centre and cause it to increase the rate of impulses sent to the sinoatrial node , or pacemaker , resulting in faster and stronger cardiac muscle contraction and thus increasing the heart rate .

negative: Abdominal aortic aneurysm Abdominal aortic aneurysm ( AAA or triple A ) is a localized enlargement of the abdominal aorta such that the diameter is greater than 3 cm or more than 50 % larger than normal diameter . They usually cause no symptoms except when ruptured . Occasionally , abdominal , back , or leg pain may occur . Large aneurysms can sometimes be felt by pushing on the abdomen . Rupture may result in pain in the abdomen or back , low blood pressure , or loss of consciousness , and often results in death .   AAAs occur most commonly in those over 50 years old , in men , and among those with a family history . Additional risk factors include smoking , high blood pressure , and other heart or blood vessel diseases . Genetic conditions with an increased risk include Marfan syndrome and Ehlers-Danlos syndrome . AAAs are the most common form of aortic aneurysm . About 85 % occur below the kidneys with the rest either at the level of or above the kidneys . In the United States , screening with ultrasound is recommended for males between 65 and 75 years of age with a history of smoking . In the United Kingdom , screening all men over 65 is recommended . Once an aneurysm is found , further ultrasounds are typically done on a regular basis .   Not smoking is the single best way to prevent the disease . Other methods of prevention include treating high blood pressure , treating high blood cholesterol and not being overweight . Surgery is usually recommended when an AAA 's diameter grows to > 5.5 cm in males and > 5.0 cm in females . Other reasons for repair include the presence of symptoms and a rapid increase in size ( more than one centimeter per year ) . Repair may be either by open surgery or endovascular aneurysm repair ( EVAR ) . As compared to open surgery , EVAR has a lower risk of death in the short term and a shorter hospital stay , but may not always be an option . There does not appear to be a difference in longer term outcomes between the two . With EVAR there is a higher need for repeat procedures .   AAAs affect between 2 and 8 % of males over the age of 65 . Rates among women are one-fourth as high . In those with an aneurysm less than 5.5 cm the risk of rupture in the next year is less than 1 % . Among those with an aneurysm between 5.5 and 7 cm , the risk is about 10 % , while for those with an aneurysm greater than 7 cm the risk is about 33 % . Mortality if ruptured is 85 % to 90 % . During 2013 , aortic aneurysms resulted in 168,200 deaths , up from 100,000 in 1990 . In the United States AAAs resulted in between 10,000 and 18,000 deaths in 2009 .

negative: Myogenic mechanism The myogenic mechanism is how arteries and arterioles react to an increase or decrease of blood pressure to keep the blood flow within the blood vessel constant .   The smooth muscle of the blood vessels reacts to the stretching of the muscle by opening ion channels , which cause the muscle to depolarize , leading to muscle contraction . This significantly reduces the volume of blood able to pass through the lumen , which reduces blood flow through the blood vessel . Alternatively when the smooth muscle in the blood vessel relaxes , the ion channels close , resulting in vasodilation of the blood vessel ; this increases the rate of flow through the lumen .   This system is especially significant in the kidneys , where the glomerular filtration rate ( the rate of blood filtration by the nephron ) is particularly sensitive to changes in blood pressure . However , with the aid of the myogenic mechanism , the glomerular filtration rate remains very insensitive to changes in human blood pressure .   Myogenic mechanisms in the kidney are part of the autoregulation mechanism which maintains a constant renal blood flow at varying arterial pressure . Concomitant autoregulation of glomerular pressure and filtration indicates regulation of preglomerular resistance . Model and experimental studies were performed to evaluate two mechanisms in the kidney , myogenic response and tubuloglomerular feedback . A mathematical model showed good autoregulation through a myogenic response , aimed at maintaining a constant wall tension in each segment of the preglomerular vessels . Tubuloglomerular feedback gave rather poor autoregulation . The myogenic mechanism showed ` descending ' resistance changes , starting in the larger arteries , and successively affecting downstream preglomerular vessels at increasing arterial pressures . This finding was supported by micropuncture measurements of pressure in the terminal interlobular arteries . Evidence that the mechanism was myogenic was obtained by exposing the kidney to a subatmospheric pressure of 40 mmHg ; this led to an immediate increase in renal resistance , which could not be prevented by denervation or various blocking agents .

negative: Thermoregulation Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries , even when the surrounding temperature is very different . A thermoconforming organism , by contrast , simply adopts the surrounding temperature as its own body temperature , thus avoiding the need for internal thermoregulation . The internal thermoregulation process is one aspect of homeostasis : a state of dynamic stability in an organism 's internal conditions , maintained far from thermal equilibrium with its environment ( the study of such processes in zoology has been called physiological ecology ) . If the body is unable to maintain a normal temperature and it increases significantly above normal , a condition known as hyperthermia occurs . For humans , this occurs when the body is exposed to constant temperatures of approximately 55 ° C , and with prolonged exposure ( longer than a few hours ) at this temperature and up to around 75 ° C death is almost inevitable . Humans may also experience lethal hyperthermia when the wet bulb temperature is sustained above 35 ° C for six hours . The opposite condition , when body temperature decreases below normal levels , is known as hypothermia . It results when the homeostatic control mechanisms of heat within the body malfunction , causing the body to lose heat faster than producing it . Normal body temperature is around 37 ° C , and hypothermia sets in when the core body temperature gets lower than 35 ° C. Usually caused by prolonged exposure to cold temperatures , hypothermia is usually treated by methods that attempt to raise the body temperature back to a normal range .   It was not until the introduction of thermometers that any exact data on the temperature of animals could be obtained . It was then found that local differences were present , since heat production and heat loss vary considerably in different parts of the body , although the circulation of the blood tends to bring about a mean temperature of the internal parts . Hence it is important to identify the parts of the body that most closely reflect the temperature of the internal organs . Also , for such results to be comparable , the measurements must be conducted under comparable conditions . The rectum has traditionally been considered to reflect most accurately the temperature of internal parts , or in some cases of sex or species , the vagina , uterus or bladder .   Occasionally the temperature of the urine as it leaves the urethra may be of use in measuring body temperature . More often the temperature is taken in the mouth , axilla , ear or groin .   Some animals undergo one of various forms of dormancy where the thermoregulation process temporarily allows the body temperature to drop , thereby conserving energy . Examples include hibernating bears and torpor in bats .

negative: Arteriole An arteriole -LSB- ɑrˈtɪəri.oʊl -RSB- is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries .   Arterioles have muscular walls ( usually only one to two layers of smooth muscle ) and are the primary site of vascular resistance . The greatest change in blood pressure and velocity of blood flow occurs at the transition of arterioles to capillaries . The decreased velocity of flow in the capillaries increases the blood pressure , due to Bernoulli 's principle . This induces gas and nutrients to move from the blood to the cells , due to the lower osmotic pressure outside of the capillary . The opposite process occurs when the blood leaves the capillaries and enters the venules , where the blood pressure drops due to an increase in flow rate . Arterioles receive autonomic nervous system innervation and respond to various circulating hormones in order to regulate their diameter . Retinal vessels lack a functional sympathetic innervation .  Further local responses to stretch , carbon dioxide , pH , and oxygen also influence arteriolar tone . Generally , norepinephrine and epinephrine ( hormones produced by sympathetic nerves and the adrenal gland medulla ) are vasoconstrictive acting on alpha 1-adrenergic receptors . However , the arterioles of skeletal muscle , cardiac muscle , and pulmonary circulation vasodilate in response to these hormones when they act on beta-adrenergic receptors . Generally , stretch and high oxygen tension increase tone , and carbon dioxide and low pH promote vasodilation . Pulmonary arterioles are a noteworthy exception as they vasodilate in response to high oxygen . Brain arterioles are particularly sensitive to pH with reduced pH promoting vasodilation . A number of hormones influence arteriole tone such as angiotensin II ( vasoconstrictive ) , endothelin ( vasoconstrictive ) , bradykinin ( vasodilation ) , atrial natruretic peptide ( vasodilation ) , and prostacyclin ( vasodilation ) .   Blood pressure in the arteries supplying the body is a result of the work needed to pump the cardiac output ( the flow of blood pumped by the heart ) through the vascular resistance , usually termed total peripheral resistance by physicians and researchers . An increase in the media to lumenal diameter ratio has been observed in hypertensive arterioles ( arteriolosclerosis ) as the vascular wall thickens and/or lumenal diameter decreases .

negative: Constriction Constriction is a method used by various snake species to kill their prey . Although some species of venomous and mildly venomous snakes do use constriction to subdue their prey , most snakes which use constriction lack venom . The snake initially strikes at its prey and holds on , pulling the prey into its coils or , in the case of very large prey , pulling itself onto the prey . The snake will then wrap one or two coils around the prey . The snake will monitor the prey 's heartbeat to ascertain when it is dead .   Contrary to myth , the snake does not crush the prey , or break its bones . Also , contrary to previous belief , the snake does not cause suffocation by constricting the victim . Instead , a study of death caused by boa constrictors , showed that constriction `` shuts off '' blood flow ( and therefore oxygen ) needed by vital organs such as the heart and brain , which would lead to unconsciousness and death very quickly -- in seconds -- in other words , constriction can interrupt blood flow and overwhelm the prey 's usual blood pressure and circulation . Artery pressure drops , vein pressure increases , and blood vessels begin to close . The heart does not have enough strength to pump against the pressure and blood flow stops . Internal organs with high metabolic rates , including the brain , liver , and the heart begin to stop and die due to ischemia , a loss of oxygen and glucose . There is evidence that boa constrictors have more difficulty killing ectotherms , animals like lizards and snakes that rely on external heat to regulate their body temperatures . A boa constrictor was observed attacking a spinytail iguana for an hour , and the iguana survived .   As this is comparatively recent research ( 2015 ) , it is possible that other constrictors kill in other ways . It had previously been accepted that constrictors used their body to hold the prey tight and prevent the prey from drawing air into its lungs , resulting in death from asphyxia , or that the pressure of constriction causes a rise in the pressure in the prey 's body cavity greater than the heart can counter , resulting in immediate cardiac arrest ; data from earlier studies had also indicated that snakes can exert enough pressure for these to be plausible .   Certain groups of snakes have characteristic patterns of constriction , including the number of coils they use and the orientation of the coils .   Venomous snakes that also use constriction include the mussuranas ( ophiophagous South American mildly venomous rear-fanged colubrids which use constriction to subdue snakes including pit vipers ) , the western terrestrial garter snake ( North American colubrid which is an inefficient constrictor and , like most Thamnophis garter snakes , mildly venomous ) , some species of Boiga snakes ( Asian and Australian rear-fanged colubrids ) including the brown tree snake ( Boiga irregularis ) , some species of Australian elapids ( including some of the venomous Pseudonaja brown snakes and one Australian coral snake Simoselaps ) , and a few Australian colubrids .

negative: Acute Local Blood Flow Regulation Acute local blood flow regulation refers to the rapid control of arterial vasomotion usually based on the metabolic needs of the surrounding cells . Although cardiac output may remain the same , blood flow to individual cells is chiefly dependent on the cells ' need for nutrients .   For example , during exercise such as running , the metabolic needs of the active leg skeletal muscles increase significantly . The muscle cells are in much more demand for nutrients such as oxygen . However , the body `` reserves '' as much blood as possible to the active tissues ( in this case skeletal muscle ) . Therefore , during exercise more blood will flow to-and-from the muscle than it will in inactive tissue , such as the hand muscles .   It should also be pointed out that an increase in the diameter of a blood vessel will also increase the volume of blood flow that passes through . More blood flow would also result in a higher concentration of nutrients .   There are currently two major theories of the mechanism behind local control of blood flow . They include the vasodilator theory and the oxygen lack theory .

negative: Capacitance of blood vessels The capacitance of blood vessels describes the distensibility of blood vessels located within the body ; it is inversely proportional to elasticity . Therefore , the greater the amount of elastic tissue in a blood vessel , the greater the elasticity , and the smaller the compliance . This ultimately describes how volume changes in response to a change in pressure within the blood vessel at hand .   C = ∆ V / ∆ P where , C = capacitance , or compliance ( mL/mmHg )  ∆ V = change in volume ( mL )  ∆ P = change in pressure ( mmHg )   The relationship between vascular capacitance , pressure , and flow rate is  Q = C ( dP/dt )  Q = flow rate ( cm ^ 3/sec )  Category : Blood   Distensibility in the left heart blood circulation shows decreased values due to constant exposure to high pressure and high elastin content .

negative: Aprotinin The drug aprotinin ( Trasylol , previously Bayer and now Nordic Group pharmaceuticals ) , is the small protein bovine pancreatic trypsin inhibitor ( BPTI ) , an antifibrinolytic molecule that inhibits trypsin and related proteolytic enzymes . Under the trade name Trasylol , aprotinin was used as a medication administered by injection to reduce bleeding during complex surgery , such as heart and liver surgery . Its main effect is the slowing down of fibrinolysis , the process that leads to the breakdown of blood clots . The aim in its use was to decrease the need for blood transfusions during surgery , as well as end-organ damage due to hypotension ( low blood pressure ) as a result of marked blood loss . The drug was temporarily withdrawn worldwide in 2007 after studies suggested that its use increased the risk of complications or death ; this was confirmed by follow-up studies . Trasylol sales were suspended in May 2008 , except for very restricted research use . In February 2012 the European Medicines Agency ( EMA ) scientific committee reverted its previous standpoint regarding aprotinin , and has recommended that the suspension be lifted . Nordic became distributor of aprotinin in 2012 .

negative: Patent ductus arteriosus Patent ductus arteriosus ( PDA ) is a condition wherein the ductus arteriosus fails to close after birth .   Early symptoms are uncommon , but in the first year of life include increased ` work of breathing ' and poor weight gain . An uncorrected PDA may lead to congestive heart failure with increasing age .   The ductus arteriosus is a fetal blood vessel that closes soon after birth . In a PDA , the vessel does not close and remains `` patent '' ( open ) , resulting in irregular transmission of blood between the aorta and the pulmonary artery . PDA is common in newborns with persistent respiratory problems such as hypoxia , and has a high occurrence in premature newborns . Premature newborns are more likely to be hypoxic and have PDA due to underdevelopment of the heart and lungs .   A PDA allows a portion of the oxygenated blood from the left heart to flow back to the lungs by flowing from the aorta ( which has higher pressure ) to the pulmonary artery . If this shunt is substantial , the neonate becomes short of breath : the additional fluid returning to the lungs increases lung pressure , which in turn increases the energy required to inflate the lungs . This uses more calories than normal and often interferes with feeding in infancy . This condition , as a constellation of findings , is called congestive heart failure .   In some congenital heart defects ( such as in transposition of the great vessels ) a PDA may need to remain open , as it is the only way that oxygenated blood can mix with deoxygenated blood . In these cases , prostaglandins are used to keep the DA open until surgical correction of the heart defect is completed .

negative: Permissive hypotension Permissive hypotension or hypotensive resuscitation is the use of restrictive fluid therapy , specifically in the trauma patient , that increases systemic blood pressure without reaching normotension ( normal blood pressures ) . The goal blood pressure for these patients is a mean arterial pressure of 40-50mmHg or a systolic blood pressure less than or equal to 80 . This goes along with certain clinical criteria . Following traumatic injury some patients experience hypotension ( low blood pressure ) that is usually due to blood loss ( hemorrhage ) but can be due to other causes as well ( for example , blood leaking around an abdominal aortic aneurysms ) . In the past , physicians were very aggressive with fluid resuscitation ( giving fluids such as normal saline or lactated Ringer 's through the vein ) to try to bring the blood pressure to normal values . Recent studies have found that there is some benefit to allowing specific patients to experience some degree of hypotension in certain settings . This concept does not exclude therapy by means of i.v. fluid , inotropes or vasopressors , the only restriction is to avoid completely normalizing blood pressure in a context where blood loss may be enhanced . When a person starts to bleed ( big or small ) the body starts a natural coagulation process that eventually stops the bleed . Issues with fluid resuscitation without control of bleeding is thought to be secondary to dislodgement of the thrombus ( blood clot ) that is helping to control further bleeding . Thrombus dislodgement was found to occur at a systolic pressure greater than 80mm Hg . In addition , fluid resuscitation will dilute coagulation factors that help form and stabilize a clot , hence making it harder for the body to use its natural mechanisms to stop the bleeding . These factors are aggravated by hypothermia ( if fluids are administered without being warmed first it will cause body temperature to drop ) .   It is becoming common in hemorrhaging patients without traumatic brain injury . Due to the lack of controlled clinical trials in this field , the growing evidence that hypotensive resuscitation results in improved long-term survival mainly stems from experimental studies in animals . Numerous animal models of uncontrolled hemorrhagic shock have demonstrated improved outcomes when a lower than normal blood pressure ( mean arterial pressure of 60 to 70 mmHg ) is taken as the target for fluid administration during active hemorrhage . The first published study in humans , in victims of penetrating torso trauma , has demonstrated a significant reduction in mortality when fluid resuscitation was restricted in the prehospital period . However , it is important to note that the objective of that study was the comparison between standard prehospital and trauma center fluid resuscitation versus delayed onset of fluid resuscitation ( fluid not administered until patients reached the operating room ) . A more recent study ( 2011 ) performed by the Baylor group on patients who required emergency surgery secondary to hemorrhagic shock was randomized to a mean arterial pressure ( MAP ) of 50mmHg versus 65mm Hg . The lower MAP group was found to need less total IV fluids , used less blood products , had lower early mortality ( within the first 24 hours - which accounts for a large portion of mortality in trauma patients ) and trend towards lower 30-day mortality and less postoperative coagulation , concluding that permissive hypotension is safe . Two large human trials of this technique have been conducted , which demonstrated the safety of this approach relative to the conventional target ( greater than 100 mmHg ) , and suggested various benefits , including shorter duration of hemorrhage and reduced mortality . Johns Hopkins group performed a retrospective cohort review from National Trauma Data Bank that found a statistically significant difference in mortality for patients treated with pre-hospital intravenous fluids . Clinical data from well controlled , prospective trials applying the concept of permissive hypotension in trauma patients are still missing .

negative: Mitral valve The mitral valve , also known as the bicuspid valve or left atrioventricular valve , is a dual-flap valve in the heart that lies between the left atrium and the left ventricle . The mitral valve ( not to be confused with the congenital bicuspid aortic valve ) and the tricuspid valve are known collectively as the atrioventricular valves because they lie between the atria and the ventricles of the heart and control the flow of blood .   During diastole , a normally-functioning mitral valve opens as a result of increased pressure from the left atrium as it fills with blood ( preloading ) . As atrial pressure increases above that of the left ventricle , the mitral valve opens . Opening facilitates the passive flow of blood into the left ventricle . Diastole ends with atrial contraction , which ejects the final 20 % of blood that is transferred from the left atrium to the left ventricle . This amount of blood is known as end-diastolic volume , and the mitral valve closes at the end of atrial contraction to prevent a reversal of blood flow .

negative: Clozapine Clozapine , sold under the brand name Clozaril among others , is an atypical antipsychotic medication . It is mainly used for schizophrenia that does not improve following the use of other antipsychotic medications . In those with schizophrenia and schizoaffective disorder it may decrease the rate of suicidal behavior . It is possibly more effective than typical antipsychotics and in those who are treatment resistant . It is taken by mouth .   Clozapine is associated with a relatively high risk of low white blood cells which may result in death . To decrease this risk it is recommended that the blood be regularly monitored . Other serious risks include seizures , inflammation of the heart , high blood sugar levels , and in older people with psychosis as a result of dementia an increased risk of death . Common side effects include drowsiness , dry mouth , low blood pressure , trouble seeing , and dizziness . The potentially permanent movement disorder tardive dyskinesia occurs in about 5 % of people . Its mechanism of action is not entirely clear .   Clozapine was first made in 1958 and sold commercially in 1972 . It was the first atypical antipsychotic . It is on the World Health Organization 's List of Essential Medicines , the most effective and safe medicines needed in a health system . It is available as a generic medication . The wholesale cost in the developing world is between 0.05 and 2.10 USD per day as of 2014 .

negative: Lymphocytosis Lymphocytosis is an increase in the number of lymphocytes in the blood . In adults , lymphocytosis is present when the lymphocyte count is greater than 4000 per microliter ( 4.0 x 10 ( 9 ) / L ) , in older children greater than 7000 per microliter and in infants greater than 9000 per microliter . Lymphocytes normally represent 20 to 40 % of circulating white blood cells .   Lymphocytosis is usually detected when a complete blood count is obtained . If not provided the lymphocyte count can be calculated by multiplying the total white blood cell ( WBC ) count by the percentage of lymphocytes found in the differential count . The lymphocyte count can also be directly measured by flow cytometry .

negative: Atrial volume receptors Atrial volume receptors are low pressure baroreceptors that are found in the atria of the heart and carotid arteries .   When these receptors detect a blood volume decrease in the atria , a signal is transmitted from the receptors to the hypothalamus in the brain . The hypothalamus , in turn , increases the production of vasopressin ( ADH , AVP , or arginine vasopressin ) . These receptors also cause a renal vasodilation , resulting in increase of the water amount in the glomerular filtrate which , combined with the increased production of vasopressin by the hypothalamus , will cause water retention in urine .  This increases the blood volume , resulting in the increase of blood pressure .

negative: Training effect Training effect refers to specific changes in muscular , cardiovascular , and neurohumoral systems that lead to improvement in functional capacity and strength due to regular endurance or resistance training . It has also been defined as a reaction to the adaptive responses of the body created by a training program or as `` an elevation of metabolism produced by exercise '' .   Kenneth H. Cooper for the United States Air Force discovered this effect in the late 1960s and coined the term .   The measured effects were that muscles of respiration were strengthened , the heart was strengthened , blood pressure was sometimes lowered and the total amount of blood and number of red blood cells increased , making the blood a more efficient carrier of oxygen . VO2 Max was increased .

negative: Zones of the lung The zones of the lung divide the lung into four vertical regions , based upon the relationship between the pressure in the alveoli ( PA ) , in the arteries ( Pa ) , in the veins ( Pv ) and the pulmonary interstitial pressure ( Pi ) :   Zone 1 : PA > Pa > Pv  Zone 2 : Pa > PA > Pv  Zone 3 : Pa > Pv > PA  Zone 4 : Pa > Pi > Pv > PA   This concept is generally attributed to an article by West et al. in 1964 , but was actually proposed two years earlier by Permutt et al. . In this article , Permutt suggests `` The pressure in the pulmonary arteries and veins is less at the top than at the bottom of the lung . It is quite likely that there is a portion of the lung toward the top in an upright subject in which the pressure in the pulmonary arteries is less than alveolar pressure . ''   The concept is as follows :  Alveolar pressure ( PA ) at end expiration is equal to atmospheric pressure ( 0 cm H20 differential pressure , at zero flow ) , plus or minus 2 cm H2O ( 1.5 mmHg ) throughout the lung . On the other hand , gravity causes a gradient in blood pressure between the top and bottom of the lung of 20 mmHg in the erect position ( roughly half of that in the supine position ) . Overall , mean pulmonary venous pressure is ~ 5 mmHg . Local venous pressure falls to -5 at the apexes and rises to +15 mmHg at the bases , again for the erect lung .  Pulmonary blood pressure is typically in the range 25 -- 10 mmHg with a mean pressure of 15 mmHg . Regional arterial blood pressure is typically in the range 5 mmHg near the apex of the lung to 25 mmHg at the base .   Zone 1 is not observed in the normal healthy human lung . In normal health pulmonary arterial ( Pa ) pressure exceeds alveolar pressure ( PA ) in all parts of the lung . It is generally only observed when a person is ventilated with positive pressure or hemorrhage . In these circumstances , blood vessels can become completely collapsed by alveolar pressure ( PA ) and blood does not flow through these regions . They become alveolar dead space   Zone 2 is the part of the lungs about 3 cm above the heart . In this region blood flows in pulses . At first there is no flow because of obstruction at the venous end of the capillary bed . Pressure from the arterial side builds up until it exceeds alveolar pressure and flow resumes . This dissipates the capillary pressure and returns to the start of the cycle . Flow here is sometimes compared to a starling resistor or waterfall effect .   Zone 3 comprises the majority of the lungs in health . There is no external resistance to blood flow and blood flow is continuous throughout the cardiac cycle . Flow is determined by the Ppa-Ppv difference ( Ppa - Ppv ) , which is constant down this portion of the lung . However , transmural pressure across the wall of the blood vessels increases down this zone due to gravity . Consequently the vessels wall are more stretched so the caliber of the vessels increases causing an increase in flow due to lower resistance .   Zone 4 can be seen at the lung bases at low lung volumes or in pulmonary oedema . Pulmonary interstitial pressure ( Pi ) rises as lung volume decreases due to reduced radial tethering of the lung parenchyma . Pi is highest at the base of the lung due to the weight of the above lung tissue . Pi can also rise due to an increased volume of ` leaked ' fluid from the pulmonary vasculature ( pulmonary oedema ) . An increase in Pi causes extraalveolar blood vessels to reduce in caliber , in turn causing blood flow to decrease ( extraalveolar blood vessels are those blood vessels outside alveoli ) . Intraalveolar blood vessels ( pulmonary capillaries ) are thin walled vessels adjacent to alveoli which are subject to the pressure changes described by zones 1-3 . Flow in zone 4 is governed by the arteriointerstitial pressure difference ( Pa − Pi ) . This is because as Pi rises , the arterial caliber is reduced , thereby increasing resistance to flow . The Pa/Pv difference remains unchanged since Pi is applied over both vessels .   The ventilation/perfusion ratio is higher in zone # 1 ( the apex of lung ) when a person is standing than it is in zone # 3 ( the base of lung ) because perfusion is nearly absent . However , ventilation and perfusion are highest in base of the lung , resulting in a comparatively lower V/Q ratio .

negative: Warm-blooded Warm-blooded animal species can maintain a body temperature higher than their environment . In particular , homeothermic species maintain a stable body temperature by regulating metabolic processes . The only known homeotherms are birds , mammals and the Opah fish . Other species have various degrees of thermoregulation .   Animal body temperature control varies by species , so the terms `` warm-blooded '' and `` cold-blooded '' ( though still in everyday use ) suggest a false idea of there being only two categories of body temperature control , and are no longer used scientifically .

negative: Pre-eclampsia Pre-eclampsia ( PE ) is a disorder of pregnancy characterized by the onset of high blood pressure and often a significant amount of protein in the urine . The condition begins after 20 weeks of pregnancy . In severe disease there may be red blood cell breakdown , a low blood platelet count , impaired liver function , kidney dysfunction , swelling , shortness of breath due to fluid in the lungs , or visual disturbances . Pre-eclampsia increases the risk of poor outcomes for both the mother and the baby . If left untreated , it may result in seizures at which point it is known as eclampsia .   Risk factors for pre-eclampsia include obesity , prior hypertension , older age , and diabetes mellitus . It is also more frequent in a woman 's first pregnancy and if she is carrying twins . The underlying mechanism involves abnormal formation of blood vessels in the placenta amongst other factors . Most cases are diagnosed before delivery . Rarely , pre-eclampsia may begin in the period after delivery . While historically both high blood pressure and protein in the urine were required to make the diagnosis , some definitions also include those with hypertension and any associated organ dysfunction . Blood pressure is defined as high when it is greater than 140 mmHg systolic or 90 mmHg diastolic at two separate times , more than four hours apart in a woman after twenty weeks of pregnancy . Pre-eclampsia is routinely screened for during prenatal care .   Recommendations for prevention include : aspirin in those at high risk , calcium supplementation in areas with low intake , and treatment of prior hypertension with medications . In those with pre-eclampsia delivery of the baby and placenta is an effective treatment . When delivery becomes recommended depends on how severe the pre-eclampsia and how far along in pregnancy a person is . Blood pressure medication , such as labetalol and methyldopa , may be used to improve the mother 's condition before delivery . Magnesium sulfate may be used to prevent eclampsia in those with severe disease . Bedrest and salt intake have not been found to be useful for either treatment or prevention .   Pre-eclampsia affects 2 -- 8 % of pregnancies worldwide . Hypertensive disorders of pregnancy ( which include pre-eclampsia ) are one of the most common causes of death due to pregnancy . They resulted in 46,900 deaths in 2015 . Pre-eclampsia usually occurs after 32 weeks ; however , if it occurs earlier it is associated with worse outcomes . Women who have had pre-eclampsia are at increased risk of heart disease and stroke later in life . The word eclampsia is from the Greek term for lightning . The first known description of the condition was by Hippocrates in the 5th century BC .

negative: Central venous pressure Central venous pressure ( CVP ) is the blood pressure in the venae cavae , near the right atrium of the heart . CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood back into the arterial system . CVP is often a good approximation of right atrial pressure ( RAP ) , although the two terms are not identical , as a pressure differential can sometimes exist between the venae cavae and the right atrium . CVP and RAP can differ when arterial tone is altered . This can be graphically depicted as changes in the slope of the venous return plotted against right atrial pressure ( where central venous pressure increases , but right atrial pressure stays the same ; VR = CVP − RAP ) .   CVP has been , and often still is , used as a surrogate for preload , and changes in CVP in response to infusions of intravenous fluid have been used to predict volume-responsiveness ( i.e. whether more fluid will improve cardiac output ) . However , there is increasing evidence that CVP , whether as an absolute value or in terms of changes in response to fluid , does not correlate with ventricular volume ( i.e. preload ) or volume-responsiveness , and so should not be used to guide intravenous fluid therapy . Nevertheless , CVP monitoring is a useful tool to guide hemodynamic therapy .  The cardiopulmonary baroreflex responds to an increase in CVP by decreasing systemic vascular resistance while increasing heart rate and ventricular contractility in dogs .