965 resultados para animal test replacement


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As condições de ambiente térmico e aéreo, no interior de instalações para animais, alteram-se durante o dia, devido à influência do ambiente externo. Para que análises estatísticas e geoestatísticas sejam representativas, uma grande quantidade de pontos distribuídos espacialmente na área da instalação deve ser monitorada. Este trabalho propõe que a variação no tempo das variáveis ambientais de interesse para a produção animal, monitoradas no interior de instalações para animais, pode ser modelada com precisão a partir de registros discretos no tempo. O objetivo deste trabalho foi desenvolver um método numérico para corrigir as variações temporais dessas variáveis ambientais, transformando os dados para que tais observações independam do tempo gasto durante a aferição. O método proposto aproximou os valores registrados com retardos de tempo aos esperados no exato momento de interesse, caso os dados fossem medidos simultaneamente neste momento em todos os pontos distribuídos espacialmente. O modelo de correção numérica para variáveis ambientais foi validado para o parâmetro ambiental temperatura do ar, sendo que os valores corrigidos pelo método não diferiram pelo teste Tukey, a 5% de probabilidade dos valores reais registrados por meio de dataloggers.

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Stress serves as an adaptive mechanism and helps organisms to cope with life-threatening situations. However, individual vulnerability to stress and dysregulation of this system may precipitate stress-related disorders such as depression. The neurobiological circuitry in charge of dealing with stressors has been widely studied in animal models. Recently our group has demonstrated a role for lysophosphatidic acid (LPA) through the LPA1 receptor in vulnerability to stress, in particular the lack of this receptor relates to robust decrease of adult hippocampal neurogenesis and induction of anxious and depressive states. Nevertheless, the specific abnormalities in the limbic circuit in reaction to stress remains unclear. The aim of this study is to examine the differences in the brain activation pattern in the presence or absence of LPA1 receptor after acute stress. For this purpose, we have studied the response of maLPA1-null male mice and normal wild type mice to an intense stressor: Tail Suspension Test. Activation induced by behaviour of brain regions involved in mood regulation was analysed by stereological quantification of c-Fos immunoreactive positive cells. We also conducted multidimensional scaling analysis in order to unravel coativation between structures. Our results revealed hyperactivity of stress-related structures such as amygdala and paraventricular nucleus of the hypothalamus in the knockout model and different patterns of coactivation in both genotypes using a multidimensional map. This data provides further evidence to the engagement of the LPA1 receptors in stress regulation and sheds light on different neural pathways under normal and vulnerability conditions that can lead to mood disorders.

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Haemoglobins constitute a set of proteins with interesting structural and functional properties, especially when the two large animal groups reptiles and fishes are focused on. Here, the crystallization and preliminary X-ray analysis of haemoglobin-II from the South American fish matrinxa (Brycon cephalus) is reported. X-ray diffraction data have been collected to 3.0 Angstrom resolution using synchrotron radiation (LNLS). Crystals were determined to belong to space group P2(1) and preliminary structural analysis revealed the presence of two tetramers in the asymmetric unit. The structure was determined using the standard molecular-replacement technique.

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Increased activity of the noradrenergic system in the amygdala has been suggested to contribute to the hyperarousal symptoms associated with post-traumatic stress disorder (PTSD). However, only two studies have examined the content of noradrenaline or its metabolites in the amygdala of rats previously exposed to traumatic stress showing inconsistent results. The aim of this study was to investigate the effects of an inescapable foot shock (IFS) procedure 1) on reactivity to novelty in an open-field (as an index of hyperarousal), and 2) on noradrenaline release in the amygdala during an acute stress. To test the role of noradrenaline in amygdala, we also investigated the effects of microinjections of propranolol, a β-adrenoreceptor antagonist, and clenbuterol, a β-adrenoreceptor agonist, into the amygdala of IFS and control animals. Finally, we evaluated the expression of mRNA levels of β-adrenoreceptors (β1 and β2) in the amygdala, the hippocampus and the prefrontal cortex. Male Wistar rats (3 months) were stereotaxically implanted with bilateral guide cannulae. After recovering from surgery, animals were exposed to IFS (10 shocks, 0.86 mA, and 6 seconds per shock) and seven days later either microdialysis or microinjections were performed in amygdala. Animals exposed to IFS showed a reduced locomotion compared to non-shocked animals during the first 5 minutes in the open-field. In the amygdala, IFS animals showed an enhanced increase of noradrenaline induced by stress compared to control animals. Bilateral microinjections of propranolol (0.5 μg) into the amygdala one hour before testing in the open-field normalized the decreased locomotion observed in IFS animals. On the other hand, bilateral microinjections of clenbuterol (30 ng) into the amygdala of control animals did not change the exploratory activity induced by novelty in the open field. IFS modified the mRNA expression of β1 and β2 adrenoreceptors in the prefrontal cortex and the hippocampus. These results suggest that an increased noradrenergic activity in the amygdala contributes to the expression of hyperarousal in an animal model of PTSD.

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Resumo: Avaliaram-se os efeitos da inclusão dietética das sementes de urucum substituindo alimentos concentrados (milho e farelo de soja) e volumoso (feno de pasto nativo da caatinga) sobre o comportamento ingestivo de ovinos. Foram utilizados vinte ovinos machos, castrados, sem padrão racial definido (SPRD) distribuídos em um delineamento inteiramente casualizado com quatro tratamentos representados pelos níveis de inclusão das sementes de urucum (0%; 10%; 23%; 35% na matéria seca), com cinco animais por tratamento. Os animais foram submetidos à observação visual para avaliação do comportamento ingestivo, foram observados a cada cinco minutos, durante 24 horas, para determinação do tempo despendido em alimentação, ruminação e ócio. Avaliaram-se os eventos comportamentais dos ovinos: tempo de alimentação (TAL), ruminação (TRUM) e ócio (TÓCIO). Determinou-se também a mastigação merícica dos ovinos, estimando-se o número de mastigações e a quantidade de bolos ruminados por unidade de tempo, além do número médio de defecação e micção, e frequência de ingestão de água. Os dados foram analisados pelo software SAS®, tendo sido realizada a comparação das médias pelo teste Tuckey, análise dos contrastes polinomiais e ortogonais para os dados que apresentaram significância. A inclusão de sementes de urucum não influenciou os parâmetros de comportamento ingestivo e nem os padrões nictmerais (P<0,05). A substituição da fibra proveniente do feno de pasto nativo pela fibra das sementes de urucum trouxe vantagens especialmente pela melhoria das eficiências de alimentação e de ruminação. [Ingestive behavior of sheeps fed with diets containing anatto seeds]. Abstract: Evaluated the effect of dietary inclusion of annatto seeds replacing concentrate feed (corn and soybean meal) and roughage (hay of native pasture from Caatinga) on feeding behavior of sheep. Twenty male undefined breed sheep and castrated were distributed in a completely randomized design into four treatments (five animals per treatment), with the inclusion of annatto seeds in the diets at levels of 0%, 10%, 23% and 35%, in dry matter basis. The animals were submitted to visual observation in order to acess their ingestive behavior, were observed every five minutes, during 24 hours, to determine time spent on feeding, rumination and idleness. The behavioral events of the sheeps evaluated were time for feeding (TAL), time for rumination (TRUM) and time of idleness (TOCIO). The ruminating chews of the sheeps was determined, thus estimating the number of chews and quantity of ruminated boli per unit of time, the average number of defecation and urination, and frequency of water intake were also determined Data were analyzed using SAS® software and the Tukey test to comparison of means. Polynomial and orthogonal contrasts were made for data that showed significance. The inclusion of annatto seeds did not influence the parameters of feeding behavior and neither nictemerals patterns. The replacement of fiber

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In a range test, one party holds a ciphertext and needs to test whether the message encrypted in the ciphertext is within a certain interval range. In this paper, a range test protocol is proposed, where the party holding the ciphertext asks another party holding the private key of the encryption algorithm to help him. These two parties run the protocol to implement the test. The test returns TRUE if and only if the encrypted message is within the certain interval range. If the two parties do not conspire, no information about the encrypted message is revealed from the test except what can be deduced from the test result. Advantages of the new protocol over the existing related techniques are that it achieves correctness, soundness, °exibility, high e±ciency and privacy simultaneously.

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