2,436,307 research outputs found

    Animal studies on Spacelab-3

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    The flight of two squirrel monkeys and 24 rates on Spacelab-3 was the first mission to provide hand-on maintenance on animals in a laboratory environment. With few exceptions, the animals grew and behaved normally, were free of chronic stress, and differed from ground controls only for gravity-dependent parameters. One of the monkeys exhibited symptoms of space sickness similar to those observed in humans, which suggests squirrel monkeys may be good models for studying the space-adaptation syndrome. Among the wide variety of parameters measured in the rats, most notable was the dramatic loss of muscle mass and increased fragility of long bones. Other interesting rat findings were those of suppressed interferon production by spleen cells, defective release of growth hormone by somatotrophs, possible dissociation of circadian pacemakers, changes in hepatic lipid and carbohydrate metabolism, and hypersensitivity of marrow cells to erythopoietin. These results portend a strong role for animals in identifying and elucidating the physiological and anatomical responses of mammals to microgravity

    A theoretical framework for estimation of AUCs in complete and incomplete sampling designs.

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    Nonclinical in vivo animal studies have to be completed before starting clinical studies of the pharmacokinetic behavior of a drug in humans. The drug exposure in animal studies is often measured by the area under the concentration versus time curve (AUC). The classic complete data design, where each animal is sampled for analysis once per time point, is usually only applicable for large animals. In the case of rats and mice, where blood sampling is restricted, the batch design or the serial sampling design needs to be considered. In batch designs samples are taken more than once from each animal, but not at all time points. In serial sampling designs only one sample is taken from each animal. In this paper we present an estimator for the AUC from 0 to the last time point that is applicable to all three designs. The variance and asymptotic distribution of the estimator are derived and confidence intervals based upon the asymptotic results are discussed and evaluated in a simulation study. Further, we define an estimator for linear combinations of AUCs and investigate its asymptotic properties mathematically as well as in simulation

    Flocking together : collective animal minds in contemporary fiction

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    The remarkable coordination displayed by animal groups such as an ant colony or a flock of birds in flight is not just a behavioral feat; it reflects a full-fledged form of collective cognition. Building on work in philosophy, cognitive approaches to literature, and animal studies, I explore how contemporary fiction captures animal collectivity. I focus on three novels that probe different aspects of animal assemblages: animals as a collective agent (in Richard Powers's The Echo Maker), animals that communicate a shared mind through dance-like movements (in Lydia Davis's The Cows), and animals that embrace a collective "we" to critique the individualism of contemporary society (in Peter Verhelst's The Man I Became). When individuality drops out of the picture of human-animal encounters in fiction, empathy becomes abstract: a matter of quasi-geometric patterns that are experienced by readers through an embodied mechanism of kinesthetic resonance

    Satellite animal tracking feasibility studies

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    A study was initiated in Tsavo National Park to determine movements and home ranges of individual elephants and their relations to overall distribution patterns and environmental factors such as rainfall. Methods used were radio tracking and observations of visually identifiable individuals. Aerial counts provided data on overall distribution. Two bulls and two cows were radio-tagged in Tsavo West and two bulls and four cows in Tsavo East, providing home range and movement data. The movements of individuals were useful in interpreting relatively major shifts in elephant distribution. Results point to the following preliminary conclusions: (1) elephants in the Tsavo area undertook long distance movements in fairly direct response to localized rainfall; (2) a subdivision of the overall population into locally distinct units may exist during the dry season but did not occur after significant rainfall; and (3) food appears to be the primary factor governing movements and distribution of elephants in the area

    Studies on the compounds lipids from X-ray irradiated animal,1.

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    For the purpose to reveal the mechanism of the biological indirect action of X-rays the author has conducted the analysis of the compound lipids of the organs of the rabbits irradiated with X-rays. Silicic acid column chromatography was applied for the fractionation of the compound lipids. Component of each fraction was analyzed by silicic acid-impregnated paper chromatography and infra-red spectrophotometory. The result proved that the compound lipids showed some qualitative and 10+-+ quantitative changes. The changes occurred mainly in glycerophosphatides showing the formation of high level lyso-phosphatidylcholine and lysophosphatidylethanolamine. The fatty acid compositions of the compound lipids were determined by means of gas-liquid chromatography. Further, polyunsaturated fatty acids were analyzed as fatty acid bromide. Major differences found in fatty acid patterns included: in the irradiated group the amount of C18-monoenoic, C18-dienoic, C18-trienoic, C20-tetraenoic and C22-acids were decreased and of C18- and C18-monoenoic acids were increased. It has been elucidated that lysophosphatides not only posesses a strong hemolytic power but also it has an action to induce swelling of the rat liver mitochondria. And it has been suggested that the lysophosphatides and ethanolamine will be responsible, at least partially, for the cell damage induced by X-rays.</p

    Mice in ecstasy : advanced animal models in the study of MDMA

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    The party drug 3,4-methylenedioxymethamphetamine -better known as MDMA or ecstasy- has numerous effects on the human body, characterized by a rush of energy, euphoria and empathy. However, also a multitude of toxic/neurotoxic effects have been ascribed to MDMA, based upon case reports and studies in animals. Given the intrinsic difficulties associated with controlled studies in human beings, most of our insights into the biology of MDMA have been gained through animal studies. The vast majority of these studies utilizes a pharmacological approach to elucidate the mechanisms by which MDMA exerts its effects. Advances in genetics during the last decade have led to the development of several mouse models (transgenic or knockout) that have greatly contributed to our understanding of MDMA biology. This review provides an overview of these genetically modified animal models, in the light of some characteristic effects of MDMA, e.g. hyperlocomotion, neurotoxicity, hyperthermia, behaviour or rewarding. Without a shadow of a doubt, the next decade will bring many more advanced animal models, such as mice with site-specific deletion or rescue of genes and more genetically modified rat models. These models will further improve our knowledge on the pharmacology and toxicity of MDMA and, possibly, may assist in developing therapies coping with potential damage in abusers of MDMA and other drugs, as well as in patients suffering from specific neuronal pathologies

    Accepting higher morbidity in exchange for sacrificing fewer animals in studies developing novel infection-control strategies.

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    Preventing bacterial infections from becoming the leading cause of death by the year 2050 requires the development of novel, infection-control strategies, building heavily on biomaterials science, including nanotechnology. Pre-clinical (animal) studies are indispensable for this development. Often, animal infection outcomes bear little relation to human clinical outcome. Here, we review conclusions from pathogen-inoculum dose-finding pilot studies for evaluation of novel infection-control strategies in murine models. Pathogen-inoculum doses are generally preferred that produce the largest differences in quantitative infection outcome parameters between a control and an experimental group, without death or termination of animals due to having reached an inhumane end-point during the study. However, animal death may represent a better end-point for evaluation than large differences in outcome parameters or number of days over which infection persists. The clinical relevance of lower pre-clinical outcomes, such as bioluminescence, colony forming units (CFUs) retrieved or more rapid clearance of infection is unknown, as most animals cure infection without intervention, depending on pathogen-species and pathogen-inoculum dose administered. In human clinical practice, patients suffering from infection present to hospital emergency wards, frequently in life-threatening conditions. Animal infection-models should therefore use prevention of death and recurrence of infection as primary efficacy targets to be addressed by novel strategies. To compensate for increased animal morbidity and mortality, animal experiments should solely be conducted for pre-clinical proof of principle and safety. With the advent of sophisticated in vitro models, we advocate limiting use of animal models when exploring pathogenesis or infection mechanisms

    Gaze cuing of attention in snake phobic women: the influence of facial expression

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    Only a few studies investigated whether animal phobics exhibit attentional biases in contexts where no phobic stimuli are present. Among these, recent studies provided evidence for a bias toward facial expressions of fear and disgust in animal phobics. Such findings may be due to the fact that these expressions could signal the presence of a phobic object in the surroundings. To test this hypothesis and further investigate attentional biases for emotional faces in animal phobics, we conducted an experiment using a gaze-cuing paradigm in which participants\u2019 attention was driven by the task-irrelevant gaze of a centrally presented face. We employed dynamic negative facial expressions of disgust, fear and anger and found an enhanced gaze-cuing effect in snake phobics as compared to controls, irrespective of facial expression. These results provide evidence of a general hypervigilance in animal phobics in the absence of phobic stimuli, and indicate that research on specific phobias should not be limited to symptom provocation paradigms

    Speciesism, identity politics and ecocriticism : a conversation with humanists and posthumanists

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    An electronic conversation between 7 scholars from the fields of animal studies and early modern studies aimed at confronting "speciesism," and constructing what Cary Wolfe calls a "posthumanist theory of the subject.
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