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The effect of ambient temperature on serotonin syndromeUnknown Date (has links)
Serotonin syndrome (SS) is a drug-induced toxicity caused by an excess of serotonin (5-HT) in the central nervous system (CNS). The symptoms of the disorder range from mild to severe, with the severe state evoking life-threatening hyperthermia. Autonomic dysfunction is controlled in part by serotonin receptors, with the 5-HT2A receptor responsible for increasing core body temperature (Tcor). Our results show that the 5-HT2A receptors on the preoptic/anterior hypothalamus (PO/AH) and prefrontal cortex (PFC), in particular, are sensitive to changes in ambient temperature (Tamb). The toxic increase of 5-HT is postulated to occur due to the temperature-dependent activation of these receptors that promotes a positive feedback mechanism. Our results suggest that changes in Tamb can either exacerbate or alleviate the symptom and that this is mediated by the 5-HT2A receptors. Understanding the mechanism involved in elevating Tcor is imperative in treating and preventing the disorder. / by Swapna Krishnamoorthy. / Vita. / Thesis (M.S.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.
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Processo de condicionamento e avaliação do equilíbrio térmico de bovinos Guzerá /Camerro, Leandro Zuccherato. January 2016 (has links)
Orientador: Alex Sandro Campos Maia / Banca: Marcos Chiquitelli Neto / Banca: Márcia Helena Machado da Rocha Fernandes / Resumo: O objetivo deste estudo foi validar o condicionamento dos animais e o desenvolvimento de pesquisas que visem entender as respostas do equilíbrio térmico de bovinos Guzerá (Bos indicus), em consequência das variações meteorológicas ao longo do dia, em ambiente tropical e a emissão de metano. Foram avaliados dez bovinos da raça Guzerá, cinco machos e cinco fêmeas, com média de vinte meses, alojados em baias individuais, protegidos da radiação solar. A frequência respiratória, volume respiratório corrente, a produção de calor metabólico e a perda de calor latente via sistema respiratório, foram determinados usando um sistema de calorimetria indireta, com o auxílio de uma máscara facial. Simultaneamente, foram analisadas a temperatura retal (TR), temperatura da epiderme (TEP), temperatura do pelame (TS), temperatura do ar expirado (TEXP), além das variáveis meteorológicas, temperatura do ar (TA), umidade relativa (UR), radiação solar (RS), e temperatura radiante média (TRM). Também foram determinados os fluxos de calor por radiação e convecção. As temperaturas do ar expirado, do pelame e da epiderme, se mostraram dependentes da temperatura do ar, aumentando de 28 a 35°C, 31 a 38°C e 33 a 38°C, respectivamente, quando a temperatura do ar aumentou de 25 para 34°C, enquanto que a temperatura retal foi dependente da hora do dia. A produção de calor metabólico apresentou média de 115 e 155 W m-2, para machos e fêmeas, respectivamente, e não se alterou com o aumento da temperatura do ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to validate the conditioning of animals and the development of research aimed at understanding the responses of the thermal equilibrium of Guzerá cattle (Bos indicus), as a result of weather variations throughout the day in a tropical environment and the methane emission. Evaluated ten Guzerat cattle, five males and five females, with an average of twenty months, housed in individual pens, protected from direct solar radiation. The respiratory rate, tidal respiratory volume, metabolic heat production and loss of latent heat via the respiratory system, were determined using an indirect calorimetry system with the aid of a facial mask. At the same time, we analyzed the rectal temperature (TR), skin surface temperature (TEP), hair coat temperature (TS), expired air temperature (TEXP), besides meteorological variables, air temperature (TA), relative humidity (UR), solar radiation (RS), and mean radiant temperature (TRM). It was also determined heat flow by radiation and convection. The expired air temperature, hair coat temperature and skin surface temperature, proved to be dependent on air temperature, adding 28 to 35 ° C, 31 to 38 ° C and 33 to 38 ° C, respectively, when the air temperature increased from 25 to 34 ° C. While the rectal temperature is dependent on the time of day. The metabolic heat production averaged 115 and 155 W m-2 for males and females, respectively, and did not change with increasing air temperature (25-34 ° C), the same was tru... (Complete abstract click electronic access below) / Mestre
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Análise da atividade enzimática mitocondrial e mecanismos de adaptação em bovinos submetidos ao estresse pelo calor /Ferreira, Gabriela da Silva. January 2019 (has links)
Orientador: Guilherme de Paula Nogueira / Resumo: Com aumento global da temperatura, compreender como o metabolismo de bovinos se adapta ao estresse térmico, permitirá selecionar animais melhor adaptados ao aumento da temperatura ambiente. Uma das possibilidades é compreender como cada raça responde a esse efeito ambiente. O trabalho objetivou expor ao sol duas raças distintas de bovinos com diferente resistência ao calor e estudar as alterações no metabolismo mitocondrial e comportamental após a exposição ao sol ou não por 60 dias. Foram analisados 23 animais da raça Angus – susceptível ao calor (12 ao sol e 11 sob sombra) e 25 Nelores – tolerantes ao calor (13 ao sol e 12 sob sombra). Após todos os animais passarem por período de adaptação de 60 dias, foram divididos entre os grupos e analisados os parâmetros ambientais (THI, HLI e AHLU), movimentação (por radiotelemetria), concentrações séricas de testosterona e LH por radioimunoensaio, espessura de tecido adiposo subcutâneo por ultrassonografia e atividade enzimática mitocondrial de músculo esquelético do complexo I (NADH oxidoredutase). A atividade mitocondrial foi avaliada em amostras da musculatura do tríceps braquial colhidas por biópsia periodicamente ao longo do experimento. Os parâmetros ambientais caracterizam o desconforto térmico que os animais foram submetidos, principalmente Angus sol com índice de AHLU muito acima de estresse extremo. Os Angus se movimentaram mais que os Nelore durante o período experimental (p<0,05) e os Nelore se movimentaram mais à noite ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Cattle farmers are suffering challenges in the animal breeding, consequence of the global increase of the temperature. Understanding how the homeothermic metabolism adapts to the thermal stress, allows the selection of better adapted animals to the of the environmental temperature increase. One of those possibilities is to understand each breed reacts to this ambient effect. The work aimed to expose in the sun two different bovine breeds that have different heat resistance and evaluate the mitochondrial metabolism and behavioral changes during sun exposure. Twenty three Angus - susceptible to heat (12 in the sun and 11 in shadow) and 25 Nellore - heat tolerant (13 in the sun and 12 in shadow) animals were analyzed. After all the animals went through a 60 days adaptation period, the animals were sorted composing the groups and analyzed the environmental parameters, movement (by radiotelemetry) subcutaneous fat thickeness and mitochondrial enzymatic activity from squelectical muscle samples.The activity mitochondria were evaluated by the enzymatic reaction of the compound I (NADH oxidoreductase) in muscular tissue samples that were collected periodically during the experiment. The environmental parameters characterize the thermal discomfort that the animals were subjected to, mainly Angus sun with AHLU index well above extreme stress. The Angus moved more than the Nellore during the experimental period (p <0.05) and the Nellore moved more at night compared to the day (p <0.05).... (Complete abstract click electronic access below) / Doutor
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Análise da atividade enzimática mitocondrial e mecanismos de adaptação em bovinos submetidos ao estresse pelo calor / Analysis of mitochondrial enzymatic activity and adaptation mechanisms in bovines submitted to heat stressFerreira, Gabriela da Silva 21 January 2019 (has links)
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Previous issue date: 2019-01-21 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Com aumento global da temperatura, compreender como o metabolismo de bovinos se adapta ao estresse térmico, permitirá selecionar animais melhor adaptados ao aumento da temperatura ambiente. Uma das possibilidades é compreender como cada raça responde a esse efeito ambiente. O trabalho objetivou expor ao sol duas raças distintas de bovinos com diferente resistência ao calor e estudar as alterações no metabolismo mitocondrial e comportamental após a exposição ao sol ou não por 60 dias. Foram analisados 23 animais da raça Angus – susceptível ao calor (12 ao sol e 11 sob sombra) e 25 Nelores – tolerantes ao calor (13 ao sol e 12 sob sombra). Após todos os animais passarem por período de adaptação de 60 dias, foram divididos entre os grupos e analisados os parâmetros ambientais (THI, HLI e AHLU), movimentação (por radiotelemetria), concentrações séricas de testosterona e LH por radioimunoensaio, espessura de tecido adiposo subcutâneo por ultrassonografia e atividade enzimática mitocondrial de músculo esquelético do complexo I (NADH oxidoredutase). A atividade mitocondrial foi avaliada em amostras da musculatura do tríceps braquial colhidas por biópsia periodicamente ao longo do experimento. Os parâmetros ambientais caracterizam o desconforto térmico que os animais foram submetidos, principalmente Angus sol com índice de AHLU muito acima de estresse extremo. Os Angus se movimentaram mais que os Nelore durante o período experimental (p<0,05) e os Nelore se movimentaram mais à noite em comparação ao dia (p<0,05). As concentrações de testosterona aumentaram do período de adaptação para o experimento para ambas as raças e tratamentos. Os animais da raça Nelore apresentaram maior depósito de gordura subcutânea que os Angus. A atividade mitocondrial aumentou significativamente do período de adaptação (P0) para o experimento (P1) e não diferiu durante o experimento entre as raça e os tratamentos. Animais endotérmicos mantidos em altas temperaturas respondem com adaptações metabólicas e comportamentais mediante o estresse exposto. Os Nelore se movimentam mais à noite quando a temperatura é mais amena e os Angus durante o dia à procura de conforto térmico. A atividade mitocondrial é aumentada devido a alta demanda de ATP provavelmente em repercussão da necessidade de sinalizar biogênese mitocondrial, reparação celular, movimentação e níveis aumentados de testosterona. / Cattle farmers are suffering challenges in the animal breeding, consequence of the global increase of the temperature. Understanding how the homeothermic metabolism adapts to the thermal stress, allows the selection of better adapted animals to the of the environmental temperature increase. One of those possibilities is to understand each breed reacts to this ambient effect. The work aimed to expose in the sun two different bovine breeds that have different heat resistance and evaluate the mitochondrial metabolism and behavioral changes during sun exposure. Twenty three Angus - susceptible to heat (12 in the sun and 11 in shadow) and 25 Nellore - heat tolerant (13 in the sun and 12 in shadow) animals were analyzed. After all the animals went through a 60 days adaptation period, the animals were sorted composing the groups and analyzed the environmental parameters, movement (by radiotelemetry) subcutaneous fat thickeness and mitochondrial enzymatic activity from squelectical muscle samples.The activity mitochondria were evaluated by the enzymatic reaction of the compound I (NADH oxidoreductase) in muscular tissue samples that were collected periodically during the experiment. The environmental parameters characterize the thermal discomfort that the animals were subjected to, mainly Angus sun with AHLU index well above extreme stress. The Angus moved more than the Nellore during the experimental period (p <0.05) and the Nellore moved more at night compared to the day (p <0.05). Testosterone concentrations increased from the adaptation period to the experimental for both breeds and treatments. The animals of the Nelore breed presented greater subcutaneous fat deposition than the Angus. Enzymatic mitochondrial activity increased significantly from the adaptation period (P0) to the experiment (P1) and did not differ during the experiment between breed and treatments. Homeothermic animals kept at high temperatures respond with metabolic and behavioral adaptations through exposed stress. The Nelore move more at night when the temperature is milder and the Angus during the day looking for thermal comfort. Mitochondrial activity is increased due to high ATP demand probably in repercussion of the need to signal mitochondrial biogenesis, cell repair, movement and increased levels of testosterone.
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Kroppstemperatur och vattenavdunstning via huden hos extremt underburna barn vid vård i kuvös och med kängurumetodenKarlsson, Victoria, Heinemann, Ann-Britt January 2009 (has links)
<p>Aim: To examine the reaction of extreme preterm infants with regarding to body temperature and transepidermal water loss during skin-to-skin care according to Kangaroo Mother Care (KMC) during the infant’s first week of life. Method: This was a descriptive quantitatively designed study, which was a pilot study within the framework of a larger project. Nine children, with a median gestational age of 24.91 weeks, were examined by measuring body temperature (axilla and skin temperature) as well as transepidermal water loss before, during and after KMC. Results: The study showed that skin temperature tended to rise during KMC, especially for those children who were nursed with KMC for more than 60 minutes. Eight out of nine children had, after completing KMC, a normal axilla temperature. As was expected, transepidermal water loss was elevated when measured both pre and post test. Despite this, the children showed normal body temperature. Conclusion: The results of the study support that KMC can create a micro-climate that, for at least one hour, makes it possible for even extreme preterm infants to maintain a body temperature within the normal range during their first week of life.</p>
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Connecting microevolutionary processes with macroevolutionary patterns across space and timeUyeda, Josef C. 15 October 2013 (has links)
Whether microevolutionary processes can explain macroevolutionary patterns has long been a matter of contentious debate. The debate has persisted largely because of the challenging task of connecting microevolutionary theory, which examines population-level phenomena on the generation scale, to data collected across larger spatial and temporal scales. My dissertation research broadly examines phenotypic evolution across multiple scales by connecting microevolutionary theory to macroevolutionary phenomena such as speciation and large-scale phenotypic change. In particular, I focus on the so-called "paradox of stasis"; which wrestles with the apparent conflict between frequently-observed cases of rapid evolution on short timescales and the frequent appearance of stasis in the fossil record. I attempt to link micro and macroevolution by using the theoretical framework of evolutionary quantitative genetics for modeling the effects of drift and selection. My four dissertation chapters examine four different systems (1) connecting quantitative genetic models of sexual selection to speciation (2) connecting microevolutionary and macroevolutionary body size data across scales of time (3) using phylogenetic comparative methods and quantitative genetic models to examine the evolution of a classic example of stasis, mammalian body temperature and (4) finally, using multi-locus phylogeography to understand the evolutionary processes that contribute to the diversification of a widespread snake across broad spatial scales. In chapter 2, I demonstrate that genetic drift combined with sexual selection can promotes speciation and diversification of male ornaments. Furthermore, I demonstrate that drift promotes the evolution of elaborate ornaments even when preferences are costly. In chapter 3, I combine data from microevolutionary field studies, the fossil record, and phylogenetic comparative data into a single analytical framework to resolve apparent conflicts between micro and macroevolutionary patterns. To do so, I compiled and analyzed the largest database of phenotypic divergence data in existence. I demonstrate that patterns of stasis persist until a million-year threshold, after which divergence begins to accumulate in a time-dependent manner. This pattern is best fit with a hierarchical model that describes evolution as occurring in bursts on the million-year timescale, but that allows for rapid, but bounded, evolution on short timescales. In chapter 4, I demonstrate that mammalian body temperature -- which has been previously presented as a classic example of stasis -- does in fact evolve extensively across the mammalian radiation (albeit slowly). Furthermore, I show that mammalian body temperature evolves in response to changing environmental conditions. Finally, I evaluate the role that genetic constraints play in the apparent slowness of body temperature evolution. In chapter 5, I examine a well-studied empirical system of garter snakes in which a strong signature of stabilizing selection has been found for phenotypic traits. Using multiple mitochondrial and nuclear loci, I show that introgression is rampant between species, and dynamic patterns of range expansion, contraction, and introgression among clades have led to a complex pattern of genetic variation. This structure of genetic variation underscores the need to examine range-wide processes for generating phenotypic divergence across clades. Overall, these chapters suggest that apparent disconnects between microevolutionary processes and macroevolutionary patterns could be explained by the scaling of population-level theory over large spatial and temporal scales. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from Oct. 25, 2012 - Oct. 25, 2013
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Measurement and evaluation of body temperature : Implications for clinical practiceSund-Levander, Märtha January 2004 (has links)
The general aim was to explore factors influencing the normal variation and measurement of body temperature. Additional aims were to study morbidity, mortality and the clinical presentation of pneumonia and predictors for survival in elderly nursing-home residents. Two hundred and thirty seven non-febrile nursing home residents (aged 66-99 years) and 87 healthy adults (aged 19-59 years) were included. In elderly individuals, the morning ear and rectal body temperature was measured at baseline and pneumonia and survival was observed at one- two and three-year. In healthy adults the rectal, ear, oral and axillary temperature were measured simultaneously on one morning and repeated measurements were performed in three subjects. Overall, the range of normal body temperature was wider then traditionally stated. In elderly nursinghome residents, functional and cognitive impairment and BMI < 20 were related to a lower body temperature and medication with analgesics to a higher. Compared to adults < 60 years elderly persons had a higher average ear and a lower rectal temperature. Men and postmenopausal women < 60 years had lower body temperature than premenopausal women. The repeated measurements showed a wide individual variability irrespective of the site of measurement, and that replicated measurements do not improve accuracy. When comparing the rectal temperature with oral, ear and axillary readings the average difference was > 0.5°C with a wide individual variation. The yearly incidence of nursing-home acquired pneumonia varied between 6.9% and 13.7%. Functional impairment, chronic obstructive pulmonary disease (COPD) and male sex were related to a higher risk of acquiring pneumonia and presenting non-specific symptoms were common. Age and functional impairment predicted mortality, irrespective of gender, while cerebral vascular insult, a lower body mass index and malnutrition in women and heart disease, COPD, medication with sedatives and mortality rate index in men were gender specific predictors. Surviving women had a higher baseline body temperature than non-surviving, while no such difference was found in men. When assessing body temperature, it is important to consider the site of measurement, technical design, operator technique, age and gender and, in elderly nursing-home residents, physical and cognitive impairment, body constitution and medication with analgesics. The best approach is to use an unadjusted mode, without adjusting to another site. To prevent a delayed diagnosis of pneumonia, one should be aware of a low baseline body temperature and lack of specific clinical symptoms in elderly nursing-home residents. Preserving and/or improving functional, cognitive, nutritional status and preventing agitation and confusion would improve survival in nursing-home residents.
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Protection against cold in prehospital trauma careHenriksson, Otto January 2012 (has links)
Background: Protection against cold is vitally important in prehospital trauma care to reduce heat loss and prevent body core cooling. Objectives: Evaluate the effect on cold stress and thermoregulation in volunteer subjects byutilising additional insulation on a spineboard (I). Determine thermal insulation properties of blankets and rescue bags in different wind conditions (II). Establish the utility of wet clothing removal or the addition of a vapour barrier by determining the effect on heat loss within different levels of insulation in cold and warm ambient temperatures (III) and evaluating the effect on cold stress and thermoregulation in volunteer subjects (IV). Methods: Aural canal temperature, sensation of shivering and cold discomfort was evaluated in volunteer subjects, immobilised on non-insulated (n=10) or insulated (n=9) spineboards in cold outdoor conditions (I). A thermal manikin was setup inside a climatic chamber and total resultant thermal insulation for the selected ensembles was determined in low, moderate and high wind conditions (II). Dry and wet heat loss and the effect of wet clothing removal or the addition of a vapour barrier was determined with the thermal manikin dressed in either dry, wet or no clothing; with or without a vapour barrier; and with three different levels of insulation in warm and cold ambient conditions (III). The effect on metabolic rate, oesophageal temperature, skin temperature, body heat storage, heart rate, and cold discomfort by wet clothing removal or the addition of a vapour barrier was evaluated in volunteer subjects (n=8), wearing wet clothing in a cold climatic chamber during four different insulation protocols in a cross-over design (IV). Results: Additional insulation on a spine board rendered a significant reduction of estimated shivering but there was no significant difference in aural canal temperature or cold discomfort (I). In low wind conditions, thermal insulation correlated to thickness of the insulation ensemble. In greater air velocities, thermal insulation was better preserved for ensembles that were windproof and resistant to the compressive effect of the wind (II). Wet clothing removal or the use of a vapour barrier reduced total heat loss by about one fourth in the cold environment and about one third in the warm environment (III). In cold stressed wet subjects, with limited insulation applied, wet clothing removal or the addition of a vapour barrier significantly reduced metabolic rate, increased skin rewarming rate, and improved total body heat storage but there was no significant difference in heart rate or oesophageal temperature cooling rate (IV). Similar effects on heat loss and cold stress was also achieved by increasing the insulation. Cold discomfort was significantly reduced with the addition of a vapour barrier and with an increased insulation but not with wet clothing removal. Conclusions: Additional insulation on a spine board might aid in reducing cold stress inprolonged transportations in a cold environment. In extended on scene durations, the use of a windproof and compression resistant outer cover is crucial to maintain adequate thermal insulation. In a sustained cold environment in which sufficient insulation is not available, wet clothing removal or the use of a vapour barrier might be considerably important reducing heat loss and relieving cold stress.
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Automatic Features Identification with Infrared Thermography in Fever ScreeningSurabhi, Vijaykumar 12 January 2012 (has links)
The goal of this thesis is to develop an algorithm to process infrared images and achieve automatic identification of moving subjects with fever. The identification is based on two main features: the distinction between the geometry of a human face and other objects in the field of view of the camera, and the temperature of the radiating object. Infrared thermography is a remote sensing technique used to measure temperatures based on emitted infrared radiation. Applications include fever screening in major public places such as airports and hospitals. Current accepted practice of screening requires people to stay in a line and temperature measurements are carried out for one person at a time. However in the case of mass screening of moving people the accuracy of the measurements is still under investigation. An algorithm constituting of image processing to threshold objects based on the temperature, template matching and hypothesis testing is proposed to achieve automatic identification of fever subjects. The algorithm was first tested on training data to obtain a threshold value (used to discriminate between face and non face shapes) corresponding to a false detection rate of 5%, which in turn corresponds to 85% probability of detection using Neyman-Pearson criterion. By testing the algorithm on several simulated and experimental images (which reflect relevant scenarios characterizing crowded places) it is observed that it can be beneficially implemented to introduce automation in the process of detecting moving subjects with fever.
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Automatic Features Identification with Infrared Thermography in Fever ScreeningSurabhi, Vijaykumar 12 January 2012 (has links)
The goal of this thesis is to develop an algorithm to process infrared images and achieve automatic identification of moving subjects with fever. The identification is based on two main features: the distinction between the geometry of a human face and other objects in the field of view of the camera, and the temperature of the radiating object. Infrared thermography is a remote sensing technique used to measure temperatures based on emitted infrared radiation. Applications include fever screening in major public places such as airports and hospitals. Current accepted practice of screening requires people to stay in a line and temperature measurements are carried out for one person at a time. However in the case of mass screening of moving people the accuracy of the measurements is still under investigation. An algorithm constituting of image processing to threshold objects based on the temperature, template matching and hypothesis testing is proposed to achieve automatic identification of fever subjects. The algorithm was first tested on training data to obtain a threshold value (used to discriminate between face and non face shapes) corresponding to a false detection rate of 5%, which in turn corresponds to 85% probability of detection using Neyman-Pearson criterion. By testing the algorithm on several simulated and experimental images (which reflect relevant scenarios characterizing crowded places) it is observed that it can be beneficially implemented to introduce automation in the process of detecting moving subjects with fever.
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