Scientific Reviews (scientific + review)

Distribution by Scientific Domains


Selected Abstracts


Surrogate endpoints and emerging surrogate endpoints for risk reduction of cardiovascular disease

NUTRITION REVIEWS, Issue 2 2008
Crystal M Rasnake
This article reviews surrogate endpoints and emerging biomarkers that were discussed at the annual "Cardiovascular Biomarkers and Surrogate Endpoints" symposium cosponsored by the US Food and Drug Administration (FDA) and the Montreal Heart Institute. The FDA's Center for Food Safety and Applied Nutrition (CFSAN) uses surrogate endpoints in its scientific review of a substance/disease relationship for a health claim. CFSAN currently recognizes three validated surrogate endpoints: blood pressure, blood total cholesterol, and blood low-density lipoprotein (LDL) concentration in its review of a health claim for cardiovascular disease (CVD). Numerous potential surrogate endpoints of CVD are being evaluated as the pathophysiology of heart disease is becoming better understood. However, these emerging biomarkers need to be validated as surrogate endpoints before they are used by CFSAN in the evaluation of a CVD health claim. [source]


The neurophysiology of dyspnea

JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 6 2008
Matthew Scott Mellema DVM
Abstract Objective , To review the human and veterinary literature regarding the neurophysiology of dyspnea and to provide evidence for the beneficial effects of several novel therapies aimed at the alleviation of dyspneic sensations. Data Sources , Data sources included scientific reviews, case reports, original research publications, and recent research conference proceedings. Human Data Synthesis , The use of blood oxygenation level-dependent functional magnetic resonance imaging technology has revealed that the brain regions activated by air hunger in humans are also those activated by fear, pain, and thirst perception. In human subjects, it has been found that agents known to enhance the firing of pulmonary slowly adapting receptors (SARs) can alleviate the sensation of dyspnea without altering central respiratory drive. Several small studies have also shown that nebulized opioids can reduce the sensation of dyspnea apparently via activation of peripheral opioid receptors in the lung. Veterinary Data Synthesis , There are several animal models relevant to both small and large animal clinical patient populations. Treatment of rats with a nebulized SAR sensitizing agent (furosemide) enhances SAR firing in response to lung inflation. Behavioral escape responses to airway occlusion are reduced in lightly anesthetized cats when treated with nebulized furosemide. Opioid agonists have been shown to inhibit the release of acetylcholine and other mediators from the airways of dogs and guinea pigs. Studies using a goat model with bilateral destruction of the pre-Bötzinger Complex do not support current paradigms of air hunger origination. Conclusions , Veterinary patients may benefit from an approach to dyspnea that incorporates an understanding of the origins of the unpleasant sensations associated with the condition. Several novel therapies have shown promise in alleviating dyspneic sensations without altering respiratory drive. Further study is needed to determine the safety and efficacy of these therapies in veterinary patients. [source]


Use of dopamine in acute renal failure

JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 2 2007
DACVECC, Nadja E. Sigrist DrMedVet
Abstract Objective: To review the current understanding of dopamine and its use in the prevention and treatment of acute renal failure (ARF). Data sources: Original research articles and scientific reviews. Human data synthesis: Low-dose dopamine administration has been shown to increase natriuresis and urinary output in both healthy individuals and in a few small studies in human patients with renal insufficiency. However, in several large meta-analyses, dopamine treatment did not change mortality or the need for dialysis. Due to the potential side effects, the use of dopamine for prevention and treatment of ARF is no longer recommended in human medicine. Veterinary data synthesis: Low-dose dopamine increases urinary output in healthy animals and animal models of ARF if given before the insult. There are no available studies looking at the effect of low-dose dopamine therapy in naturally occurring ARF in dogs or cats. Conclusion: Due to the potential side effects of low-dose dopamine therapy, the results from large human trials, and the lack of information in veterinary medicine, the use of dopamine for treatment of ARF in veterinary patients should be further evaluated. [source]


An updated view of hemostasis: mechanisms of hemostatic dysfuntion associated with sepsis

JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 2 2005
DACVECC, Kate Hopper BVSc
Abstract Objective: To review the current understanding of mechanisms involved in normal hemostasis and to describe the changes associated with pro-inflammatory disease processes such as sepsis. Data sources: Original research articles and scientific reviews. Human data synthesis: Organ damage caused by sepsis is created in part by the interdependent relationship between hemostasis and inflammation. Markers of coagulation have been found to have prognostic value in human patients with sepsis and there are both experimental and clinical investigations of the therapeutic potential of modulating the hemostatic system in sepsis. Improvement of 28-day all-cause mortality in severe sepsis by treatment with recombinant human activated Protein C strongly supports the interdependence of hemostasis and inflammation in the pathophysiology of sepsis. Veterinary data synthesis: Publications reporting clinical evaluation of the hemostatic changes occurring in septic dogs or cats are minimal. Experimental animal models of sepsis reveal significant similarity between human and animal sepsis and may provide relevance to clinical veterinary medicine until prospective clinical evaluations are published. Conclusions: It is now apparent that inflammation and the coagulation system are intimately connected. Understanding this relationship provides some insight into the pathogenesis of the hemostatic changes associated with sepsis. This new updated view of hemostasis may lead to the development of novel therapeutic approaches to sepsis and disseminated intravascular coagulation in veterinary medicine. [source]


Thromboelastography: a tool for measuring hypercoagulability, hypocoagulability, and fibrinolysis

JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 1 2005
DACVECC, Suzanne M. Donahue VMD
Abstract Objective: To describe the technique of thromboelastography (TEG) and review the applications of this coagulation test in humans and small animals. Data sources: Data sources included scientific reviews and original research publications. Human data synthesis: TEG in humans has been used for documentation of hypercoagulable and hypocoagulable states and has been shown to be beneficial in patient management. Veterinary data synthesis: Clinical evaluation of TEG in veterinary medicine is limited; however, recent reports have documented evidence of hypercoagulability in dogs with parvovirus and protein-losing nephropathy. Additionally, many of the research models may be relevant to veterinary patients. Conclusions: TEG provides information about coagulation that is not available through routine coagulation tests. The application of TEG monitoring to veterinary patients shows promise; however, prospective clinical studies are needed. [source]


Ischemia,reperfusion injury pathophysiology, part I

JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 4 2004
DACVECC, Maureen McMichael DVM
Abstract Objective: To review the current scientific literature on ischemia,reperfusion (IR) injury in both human and veterinary medicine. To describe the normal antioxidant defense mechanisms, the pathophysiology of IR injury, and the role of neutrophils in IR injury. Data sources: Data sources include scientific reviews and original research publications in both human and veterinary medicine. Summary: IR injury is a complex pathophysiological process involving numerous pathways and body systems. Normal antioxidant defense mechanisms function to limit oxidative injury during times of health. Ischemia is the period that occurs before oxygenated blood is re-introduced and the severity of injury has been shown to correlate with the magnitude and length of ischemia in dogs. During ischemia, there is a buildup of substances (i.e., xanthine oxidase, hypoxanthine, etc.) that, upon re-introduction of oxygen, form reactive oxygen species (ROS). ROS, produced in large part upon reperfusion, can cause extensive damage to DNA, proteins, carbohydrates, and lipids. Although mammalian systems are endowed with abundant antioxidant defenses, the generation of large amounts of ROS can overwhelm these mechanisms leading to cell dysfunction and death. Neutrophils play a critical role in IR injury and may mediate the majority of mucosal and microvascular injury that occurs by releasing ROS and proteolytic enzymes. Although experimental studies have been carried out on cats, dogs, and horses there are few clinical studies on companion animals. Conclusions: The pathophysiology of IR injury is complex and involves damage by ROS to all biological membranes. Neutrophils play a major role in IR injury and initiate and propogate much of the damage. This article is intended as a review of the pathophysiology of IR injury. [source]


Ischemia,reperfusion injury: assessment and treatment, part II

JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 4 2004
DACVECC, Maureen McMichael DVM
Abstract Objective: To review the current scientific literature on ischemia,reperfusion (IR) injury in both human and veterinary medicine and to describe the assessment of IR injury, the available testing methods, and the options available for treatment. Data sources: Data sources include scientific reviews and original research publications in both human and veterinary medicine. Summary: The assessment of IR injury includes measuring products formed by the reaction of reactive oxygen species (ROS) with biological membranes, measuring levels of endogenous antioxidants, and measuring ROS themselves. Testing depends on the laboratory used, the test method chosen, the sample submitted (i.e., plasma, urine, tissue, etc.), and the timing of the test in relation to sample collection. For this reason, testing is not standardized and pharmacological data on antioxidant effectiveness are not available. Antioxidants and drugs tested have included single agents as well as ,cocktails' consisting of several agents working at different key points in the injury cascade. Conclusions: There are several new testing methods as well as new strategies for attempting to ameliorate the damage inflicted upon reperfusion and this article is intended as a review of the assessment and treatment of IR injury. [source]


On the Tasks of a Population Commission: A 1971 Statement by Donald Rumsfeld

POPULATION AND DEVELOPMENT REVIEW, Issue 3 2003
Article first published online: 20 APR 200
In its most familiar form, analytic assessment of the impact of demographic change on human affairs is the product of a decentralized cottage industry: individual scholars collecting information, thinking about its meaning, testing hypotheses, and publishing their findings. Guidance through the power of the purse and through institutional design that creates and sustains cooperating groups of researchers can impose some order and coherence on such spontaneous activity. But the sum total of the result may lack balance and leave important aspects of relevant issues inadequately explored. Even when research findings are picked up by the media and reach a broader public, the haphazardness of that process helps further to explain why the salience of population change to human welfare and its importance in public policymaking are poorly understood. The syndrome is not unique to the field of population, but the typically long time-lags with which aggregate population change affects economic and social phenomena make it particularly difficult for the topic to claim public attention. A time-tested, if less than fool-proof remedy is the periodic effort to orchestrate a systematic and thorough examination of the causes, consequences, and policy implications of demographic processes. Because the most potent frame for policymaking is the state, the logical primary locus for such stocktaking is at the country level. The Commission on Population Growth and the American Future was a uniquely ambitious enterprise of this sort. The Commission was established by the US Congress in 1970 as a result of a presidential initiative. Along with the work of two earlier British Royal Commissions on population, this US effort, mutatis mutandis, can serve as a model for in-depth examinations conducted at the national level anywhere. Chaired by John D. Rockefeller 3rd, the Commission submitted its final report to President Richard M. Nixon in March 1972. The background studies to the report were published in seven hefty volumes; an index to these volumes was published in 1975. Reproduced below is a statement to the Commission delivered on April 14, 1971 by Donald Rumsfeld, then Counsellor to President Nixon and in charge of the Office of Economic Opportunity. (Currently, Mr. Rumsfeld serves as US Secretary of Defense.) The brief statement articulates with great clarity the objectives of the Commission and the considerations that prompted them. The text originally appeared in Vol. 7 (pp. 1-3) of the Commission's background reports, which contains the statements at public hearings conducted by the Commission. National efforts toward comprehensive scientific reviews of population issues have their analogs at the international level. Especially notable on that score were the preparatory studies presented at the 1954 Rome and 1965 Belgrade world population conferences. The world population conferences that took place in Bucharest in 1974, in Mexico City in 1984, and in Cairo in 1994 were intergovernmental and political rather than scientific and technical meetings, but they also generated a fair amount of prior research. The year 2004 will break the decadal sequence of large-scale international meetings on population, and apart from the quadrennial congresses of the IUSSP, which showcase the voluntary research offerings of its members, none is being planned for the coming years. A partial substitute will be meetings organized by the UN's regional economic and social commissions. The first of these took place in 2002 for the Asia-Pacific region; the meetings for the other regions will be held in 2003-04. The analytic and technical contribution of these meetings, however, is expected to be at best modest. National efforts of the type carried out 30 years ago by the Commission on Population Growth and the American Future would be all the more salutary. [source]