974 resultados para Research animals
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Thesis (Master's)--University of Washington, 2016-06
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In both Australia and Brazil there are rapid changes occurring in the macroenvironment of the dairy industry. These changes are sometimes not noticed in the microenvironment of the farm, due to the labour-intensive nature of family farms, and the traditionally weak links between production and marketing. Trends in the external environment need to be discussed in a cooperative framework, to plan integrated actions for the dairy community as a whole and to demand actions from research, development and extension (R, D & E). This paper reviews the evolution of R, D & E in terms of paradigms and approaches, the present strategies used to identify dairy industry needs in Australia and Brazil, and presents a participatory strategy to design R, D & E actions for both countries. The strategy incorporates an integration of the opinions of key industry actors ( defined as members of the dairy and associated communities), especially farm suppliers ( input market), farmers, R, D & E people, milk processors and credit providers. The strategy also uses case studies with farm stays, purposive sampling, snowball interviewing techniques, semi-structured interviews, content analysis, focus group meetings, and feedback analysis, to refine the priorities for R, D & E actions in the region.
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Many different methods of reporting animal diets have been used in ecological research. These vary greatly in level of accuracy and precision and therefore complicate attempts to measure and compare diets, and quantitites of nutrients in those diets, across a wide range of taxa. For most birds, the carotenoid content of the diet has not been directly measured. Here, therefore, I use an avian example to show how different methods of measuring the quantities of various foods in the diet affect the relative rankings of higher taxa (families, subfamilies, and tribes), and species within these taxa, with regard to the carotenoid contents of their diets. This is a timely example, as much recent avian literature has focused on the way dietary carotenoids may be traded off among aspects of survival, fitness and signalling. I assessed the mean dietary carotenoid contents of representatives of thirty higher taxa of birds using four different carotenoid intake indices varying in precision, including trophic levels, a coarse-scale and a fine-scale categorical index, and quantitative estimates of dietary carotenoids. This last method was used as the benchmark. For comparisons among taxa, all but the trophic level index were significantly correlated with each other. However, for comparisons of species within taxa, the fine-scale index outperformed the coarse-scale index, which in turn outperformed the trophic level index. In addition, each method has advantages and disadvantages, as well as underlying assumptions that must be considered. Examination and comparison of several possible methods of diet assessment appears to highlight these so that the best possible index is used given available data, and it is recommended that such a step be taken prior to the inclusion of estimated nutrient intake in any statistical analysis. Although applied to avian carotenoids here, this method could readily be applied to other taxa and types of nutrients.
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Previous research in visual search indicates that animal fear-relevant deviants, snakes/spiders, are found faster among non fear-relevant backgrounds, flowers/mushrooms, than vice versa. Moreover, deviant absence was indicated faster among snakes/spiders and detection time for flower/mushroom deviants, but not for snake/spider deviants, increased in larger arrays. The current research indicates that the latter 2 results do not reflect on fear-relevance, but are found only with flower/mushroom controls. These findings may reflect on factors such as background homogeneity, deviant homogeneity, or background-deviant similarity. The current research removes contradictions between previous studies that used animal and social fear-relevant stimuli and indicates that apparent search advantages for fear-relevant deviants seem likely to reflect on delayed attentional disengagement from fear-relevance on control trials.
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In the last decades, increasing scientific evidence has correlated the regular consumption of (poly)phenol-rich foods to a potential reduction of chronic disease incidence and mortality. However, epidemiological evidence on the role of (poly)phenol intake against the risk of some chronic diseases is promising, but not conclusive. In this framework a proper approach to (poly)phenol research is requested, using a step by step strategy. The plant kingdom produces an overwhelming array of structurally diverse secondary metabolites, among which flavonoids and related phenolic and (poly)phenolic compounds constitute one of the most numerous and widely distributed group of natural products. To date, more than 8000 structures have been classified as members of the phytochemical class of (poly)phenol, and among them over 4000 flavonoids have been identified. For this reason, a detailed food (poly)phenolic characterization is essential to identify the compounds that will likely enter the human body upon consumption, to predict the metabolites that will be generated and to unravel the potential effects of phenolic rich food sources on human health. In the first part of this work the attention was focused on the phenolic characterization of fruit and vegetable supplements, considering the increasing attention recently addressed to the so called "nutraceuticals", and on the main coffee industry by-product, namely coffee silverskin. The interest oriented toward (poly)phenols is then extended to their metabolism within the human body, paramount in the framework of their putative health promoting effects. Like all nutrients and non-nutrients, once introduced through the diet, (poly)phenols are subjected to an intense metabolism, able to convert the native compounds into similar conjugated, as well as smaller and deeply modified molecules, which in turn could be further conjugated. Although great strides have been made in the last decades, some steps of the (poly)phenol metabolism remain unclear and are interesting points of research. In the second part of this work the research was focused on a specific bran fraction, namely aleurone, added in feed pellets and in bread to investigate the absorption, metabolism and bioavailability of its phenolic compounds in animal and humans, with a preliminary in vitro step to determine their potential bioaccesibility. This part outlines the best approaches to assess the bioavailability of specific phenolics in several experimental models. The physiological mechanisms explaining the epidemiological and observational data on phenolics and health, are still far from being unraveled or understood in full. Many published results on phenolic actions at cell levels are biased by the fact that aglycones or native compounds have been used, not considering the previously mentioned chemical and biological transformations. In the last part of this thesis work, a new approach in (poly)phenol bioactivity investigation is proposed, consisting of a medium-long term treatment of animals with a (poly)phenol source, in this specific case resveratrol, the detection of its metabolites to determine their possible specific tissue accumulation, and the evaluation of specific parameters and/or mechanism of action at target tissue level. To conclude, this PhD work has contributed to advancing the field, as novel sources of (poly)phenols have been described, the bioavailability of (poly)phenols contained in a novel specific bran fraction used as ingredient has been evaluated in animal and in humans, and, finally, the tissue accumulation of specific (poly)phenol metabolites and the evaluation of specific parameters and/or mechanism of action has been carried out. For these reasons, this PhD work should be considered an example of adequate approach to the investigation of (poly)phenols and of their bioactivity, unavoidable in the process of unequivocally defining their effects on human health.
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Laboratory-based research aimed at understanding processes regulating insulin secretion and mechanisms underlying ß-cell dysfunction and loss in diabetes often makes use of rodents, as these processes are in many respects similar between rats/mice and humans. Indeed, a rough calculation suggests that islets have been isolated from as many as 150,000 rodents to generate the data contained within papers published in 2009 and the first four months of 2010. Rodent use for islet isolation has been mitigated, to a certain extent, by the availability of a variety of insulin-secreting cell lines that are used by researchers world-wide. However, when maintained as monolayers the cell lines do not replicate the robust, sustained secretory responses of primary islets which limits their usefulness as islet surrogates. On the other hand, there have been several reports that configuration of MIN6 ß-cells, derived from a mouse insulinoma, as three-dimensional cell clusters termed ‘pseudoislets’ largely recapitulates the function of primary islet ß-cells. The Diabetes Research Group at King’s College London has been using the MIN6 pseudoislet model for over a decade and they hosted a symposium on “Pseudoislets as primary islet replacements for research”, which was funded by the UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), in London on 15th and 16th April 2010. This small, focused meeting was conceived as an opportunity to consolidate information on experiences of working with pseudoislets between different UK labs, and to introduce the theory and practice of pseudoislet culture to laboratories working with islets and/or ß-cell lines but who do not currently use pseudoislets. This short review summarizes the background to the development of the cell line-derived pseudoislet model, the key messages arising from the symposium and emerging themes for future pseudoislet research.
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This is a book for primary school teachers of English written by primary school teachers of English. It brings together the experience and expertise of teachers from around the world to provide a range of stimulating and exciting classroom activities for the primary classroom. There are 50 tried and trusted activities which have been refined and improved over the years by teachers working in diverse contexts and environments. Children will enjoy practising their English through these stimulating and motivating activities. Over 1 000 teachers were contacted and asked to send their favourite activities for teaching English to young learners. The most original and creative activities received were selected for this book. This book grew out of an Aston University - British Council research project called ‘Investigating Global Practices in Teaching English to Young Learners’.
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In this paper the projected future impact of climate change has been analyzed for the quality of living conditions of the European terrestrial vertebrates (amphibians, reptiles, birds, mammals) in the Carpathian Basin. According to the climate scenarios, warmer and drier climatic conditions are likely to occur in the Carpathian Basin by end of this century. Simultaneous analysis of climate parameters, climate simulations and animal range datasets enables us to evaluate the vulnerability of different European species to regional warming and climate change. The spatial climate analogy technique is used to analyze the estimated rapid change of the wild animals’ habitats and their northward migration. For the reference climate data of Debrecen is considered, and three spatial analogue regions are compared. The results suggest that generally a significant decline in habitats is very likely for most of the analyzed animal groups by the end of the 21st century. The largest rate of decline is estimated for birds. However, living conditions for reptiles may improve in the future due to the warmer and drier climatic conditions, which are favourable for these species.
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Sediment cores, mainly push-box samples, from a channel system of the Kiel Bay are described. The channel system, of glacial and fluviatile origin, is important for the distribution of heavy, salt-rich water entering from the North Sea through the Great Belt, Sediment erosion and transport in the channels is due entirely to currents, because the bottom lies too deep for wave action. The sediments of these channels proude information about current velocities and their frequencies. Grain-size, minor sediment structures and thickness of the sediments vary remarkably. Nevertheless, for those parts of the channels where stronger currents occur, some typical features can be shown. These include: small thickness of the marine sediments, erosional effects upon the underlying sediments, and poor sorting of the sediments, whereby fine and coarse fractions are mixed very intensively. Besides strong currents which effect the bottom configuration and deposits in the Fehmarn Belt, there must exist longer periods of low current action upon the bottom, although current measurements show that current velocities higher than 50 cm/sec at some meters above the bottom occur frequently during the year. In the channel to the west of the southern mouth of Great Belt, coarse sediments were found only in elongate, deep throughs within the channels. This is believed to be due to an acceleration of the entering tongues of heavy water as they flow downslope into the throughs. Minor structures of two sediment cores were made visible by X-ray photographs. These showed that the mixing of sand and clayey material is due partly to bottom organisms and that the mud, which appears 'homogeneous' to the bare eye, is built up of fine wavy laminae which are also partly destroyed by boring animals. At another location in the channel system, there was found a thin finegrained layer of marine sediment resting upon peat. Palynological dating of the peat shows that very little older sediment could have been eroded. The current velocities, therefore, must be too low for the movement of coarse material and erosion, but too high to allow the Sedimentation of a lot of fine-grained material.
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A pressing challenge for the study of animal ethics in early modern literature is the very breadth of the category “animal,” which occludes the distinct ecological and economic roles of different species. Understanding the significance of deer to a hunter as distinct from the meaning of swine for a London pork vendor requires a historical investigation into humans’ ecological and cultural relationships with individual animals. For the constituents of England’s agricultural networks – shepherds, butchers, fishwives, eaters at tables high and low – animals matter differently. While recent scholarship on food and animal ethics often emphasizes ecological reciprocation, I insist that this mutualism is always out of balance, both across and within species lines. Focusing on drama by William Shakespeare, Ben Jonson, and the anonymous authors of late medieval biblical plays, my research investigates how sixteenth-century theaters use food animals to mediate and negotiate the complexities of a changing meat economy. On the English stage, playwrights use food animals to impress the ethico-political implications of land enclosure, forest emparkment, the search for new fisheries, and air and water pollution from urban slaughterhouses and markets. Concurrent developments in animal husbandry and theatrical production in the period thus led to new ideas about emplacement, embodiment, and the ethics of interspecies interdependence.
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Purpose: To evaluate the immunogenicity and types of immune response of a quality-controlled modified recombinant hepatitis B surface antigen (HBsAg) plasmid encoding HBsAg in mice. Methods: The characterized plasmid DNA was used in the immunization of Balb/c mice. Three groups of mice were intramuscularly injected with three different concentrations (50, 25 and 10 μg/100 μL) of the modified plasmid. Humoral immune response was monitored by enzyme-linked immunosorbent assay (ELISA), while cellular immune response was investigated by analysis of spleen cytokine profile (TNFα, IFN γ and IL2) as well as CD69 expression level in CD4 and CD8 positive cells. Results: In general, the activated CD4 cells showing intracellular cytokines were higher than CD8 positive population of cells (p < 0.05). These findings indicate that the vaccine induced both a humoral and cellular immunity. Cytokine profile also showed high levels of TNFα, IFN γ and IL2 and CD69 expression in the group of animals immunized at a dose of 10 μg when compared to control group (p < 0.05). Conclusion: A 10 μg dose intramuscular injection of the modified DNA-based vaccine encoding HBsAg in mice induces both high humoral and cellular immune responses.
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Purpose: To investigate the ethnomedicinal claims regarding the use of Acacia jacquemontii Benth. (Fabaceae) in fever, pain and inflammation. Methods: The methanol root bark extract (AJRBM) of the plant was used in the studies. Preliminary phytochemical screening of the extract was carried out according to established methods. Analgesic, anti-inflammatory and antipyretic activities were evaluated using acetic acid-induced writhing, carrageennan-induced rat paw edema and Brewer’s yeast-induced pyrexia models, respectively. The extract was administered at doses of 50 and 100 mg/kg. Aspirin (300 mg/kg, p.o.) was used as a reference drug in all models. Normal saline (10 mL/kg p.o.) was used as negative control. Results: Phytochemical screening results indicate the presence of cardioactive glycosides, tannins, flavonoids and saponins. In the acetic acid-induced writhing model, the methanol extract exhibited significant (p < 0.05) analgesic effect with 58.98 % reduction in writhing response at a dose of 100 mg/kg, compared with untreated control group. The extract significantly (p < 0.05) reduced carrageenan-induced edema at doses of 50 and 100 mg/kg to 36.84 and 47.36 %, respectively, after 1 h of extract administration. The extract exhibited predominantly dose-dependent antipyretic effect in Brewer’s yeast-induced pyrexia model. Maximum reduction in body temperature to 37.07 and 38.29 ºC at doses of 50 and 100 mg/kg, respectively, was observed, compared with untreated group (38.90 ºC) after 1 h, but this was not significant (p < 0.05). Conclusion: The plant extract exerts inhibitory effect on peripheral pain stimuli, edema and dosedependent anti-pyrexia, and thus justifies the ethnomedicinal use of Acacia jacquemontii Benth. in the management of pain, fever and inflammation.
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Antimicrobial resistance is a major health problem. After decades of research, numerous difficulties in tackling resistance have emerged, from the paucity of new antimicrobials to the inefficient contingency plans to reduce the use of antimicrobials; consequently, resistance to these drugs is out of control. Today we know that bacteria from the environment are often at the very origin of the acquired resistance determinants found in hospitals worldwide. Here we define the genetic components that flow from the environment to pathogenic bacteria and thereby confer a quantum increase in resistance levels, as resistance units (RU). Environmental bacteria as well as microbiomes from humans, animals, and food represent an infinite reservoir of RU, which are based on genes that have had, or not, a resistance function in their original bacterial hosts. This brief review presents our current knowledge of antimicrobial resistance and its consequences, with special focus on the importance of an ecologic perspective of antimicrobial resistance. This discipline encompasses the study of the relationships of entities and events in the framework of curing and preventing disease, a definition that takes into account both microbial ecology and antimicrobial resistance. Understanding the flux of RU throughout the diverse ecosystems is crucial to assess, prevent and eventually predict emerging scaffolds before they colonize health institutions. Collaborative horizontal research scenarios should be envisaged and involve all actors working with humans, animals, food and the environment.
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There is a growing recognition of the importance of the commensal intestinal microbiota in the development and later function of the central nervous system. Research using germ-free mice (mice raised without any exposure to microorganisms) has provided some of the most persuasive evidence for a role of these bacteria in gut-brain signalling. Key findings show that the microbiota is necessary for normal stress responsivity, anxiety-like behaviors, sociability, and cognition. Furthermore, the microbiota maintains central nervous system homeostasis by regulating immune function and blood brain barrier integrity. Studies have also found that the gut microbiota influences neurotransmitter, synaptic, and neurotrophic signalling systems and neurogenesis. The principle advantage of the germ-free mouse model is in proof-of-principle studies and that a complete microbiota or defined consortiums of bacteria can be introduced at various developmental time points. However, a germ-free upbringing can induce permanent neurodevelopmental deficits that may deem the model unsuitable for specific scientific queries that do not involve early-life microbial deficiency. As such, alternatives and complementary strategies to the germ-free model are warranted and include antibiotic treatment to create microbiota-deficient animals at distinct time points across the lifespan. Increasing our understanding of the impact of the gut microbiota on brain and behavior has the potential to inform novel management strategies for stress-related gastrointestinal and neuropsychiatric disorders.