• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 295
  • 289
  • 52
  • 25
  • 24
  • 12
  • 12
  • 12
  • 10
  • 8
  • 4
  • 4
  • 3
  • 2
  • 1
  • Tagged with
  • 888
  • 380
  • 114
  • 109
  • 73
  • 69
  • 65
  • 65
  • 64
  • 59
  • 58
  • 57
  • 53
  • 52
  • 47
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Stress Response and Acclimation in the Adult Turquoise Killifish Nothobranchius furzeri

Henderson, Dallas Wade 01 August 2016 (has links)
The turquoise killifish Nothobranchius furzeri is an increasingly popular model species for comparative vertebrate research. As such, the basic physiology, including responses to one or multiple stress events are of primary interest to the present study. After successful rearing, adult male and female killifish were exposed to one or more acute confinement events. Whole-blood was taken from adult males, in addition to male and female whole-body samples for cortisol analysis. Separate adults were also sampled for tissue specific expression of corticotropin releasing hormone (CRH), mineralocorticoid receptor (MR), and glucocorticoid receptor (GR) mRNA within the cranium, gills, and liver. Following a 30 minute confinement stress, male plasma cortisol significantly differed from baseline at 30 minutes (P=0.04). Similarly, both male and female whole-body cortisol were significantly increased (P=0.004 and P=0.04, respectively) at 15 and 30 minutes post-stress. Whole-body cortisol did not differ between the sexes at any sampling point, however; expression of gill MR at 15 minutes was significantly higher in males (P=0.05). Exposure to daily repeated confinement affected the cortisol response in both males and females, resulting in lower baseline and 60 minutes post-stress values in repeatedly-stressed males (P=0.04 and P=0.006, respectively) and lower cortisol at 30 and 120 minutes post-stress in repeatedly-stressed females (P=0.04 and P=0.04). Repeated exposure also resulted in increased cranial CRH and MR at 15 minutes post-stress (P=0.02 and P=0.05, respectively) compared to singly-stressed males. In females, repeated exposure increased gill MR at 120 minutes (P=0.05), but a single stressor resulted in relatively greater expression of cranial CRH at 120 minutes (P=0.02) and MR at 15 minutes (P=0.05). Collectively, the reduced cortisol production observed in repeatedly-stressed adults coupled with only transient changes in receptor expression suggest acclimation to daily stressors can be detected in as little as one week in adult turquoise killifish. This is also the first description of the stress response on this important model species.
92

Gene-Environment Interactions in Cortisol Reactivity: Sex, Genes, and Adversity Predict Responses to Psychosocial Stress

Reid, Mark 17 June 2014 (has links)
Extreme variations in cortisol reactivity are associated with multiple psychological and physiological diseases. These variations may be explained by sex, by genetic vulnerabilities, and by exposure to either recent life stressors (severe life events or ongoing difficulties) or early life adversity (e.g., antipathy; neglect; or psychological, physical, or sexual abuse). To explore interactions among these variables, a subset of 20-22 years-old individuals (N = 373) recruited for an ongoing longitudinal cohort-sequential study of substance abuse risk factors were assessed. These individuals were interviewed about early childhood abuse and recent stressful life experiences. They were also genotyped for multiple polymorphisms within genes associated with attenuated or exaggerated cortisol reactivity (5-HTTLPR and rs25532 in SERT, rs4680 in COMT, rs5522 in MR gene NR3C2, rs110402 and rs1876831 in CRHR1, rs1799971 in OPRM1, and rs1800497 in ANKK1), participated in a laboratory social stress task, and provided salivary cortisol samples throughout the task. Results indicate that cortisol reactivity may be shaped by both early and recent life experiences and genetic vulnerabilities; most interactions between these variables differed depending on an individual's sex. Specifically, carriers of two copies of minor alleles of ANKK1, COMT, and CRHR1 displayed dysregulated cortisol that varied according to sex and early life experiences. Male minor allele carriers who experienced more severe physical abuse displayed attenuated reactivity, and males who were not severely abused displayed exaggerated responses. Female minor allele carriers displayed the opposite pattern - abused females displayed exaggerated reactivity. Carriers of major alleles did not show these patterns. Attenuated cortisol reactivity was also observed in all individuals who experienced sexual abuse or neglect, and elevated responses were observed in individuals carrying two copies of minor alleles in both SERT polymorphisms and OPRM1. Together, results inform a developmental model of cortisol dysregulation. Cortisol reactivity may present a useful endophenotype for future studies of physiological and psychological disease processes and treatment outcomes.
93

Avaliação do estresse térmico em búfalas Murrah criadas em dois diferentes sistemas de manejo nas condições climáticas da amazônia oriental / Evaluation of heat stress in Murrah buffaloes reared in two different management systems in the climatic conditions of eastern Amazonia

Silva, Jamile Andréa Rodrigues da January 2010 (has links)
SILVA, Jamile Andréa Rodrigues da. Avaliação do estresse térmico em búfalas Murrah criadas em dois diferentes sistemas de manejo nas condições climáticas da amazônia oriental. 2010. 148 f. Tese (doutorado em zootecnia)- Universidade Federal do Ceará, Fortaleza-CE, 2013. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-04-08T18:27:25Z No. of bitstreams: 1 2010_tese_jarsilva.pdf: 662909 bytes, checksum: cc07a727cac604497102d21b244879f5 (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-05-25T21:33:41Z (GMT) No. of bitstreams: 1 2010_tese_jarsilva.pdf: 662909 bytes, checksum: cc07a727cac604497102d21b244879f5 (MD5) / Made available in DSpace on 2016-05-25T21:33:41Z (GMT). No. of bitstreams: 1 2010_tese_jarsilva.pdf: 662909 bytes, checksum: cc07a727cac604497102d21b244879f5 (MD5) Previous issue date: 2010 / This thesis aimed at evaluate the effects of heat stress on physiological, hematologic and hormonal responses of female buffaloes raised under full sun and shade at Embrapa Eastern Amazon, Belem, Para State, Brazil (01°.26’.03” S e 48°.26’.03” W). Twenty female Murrah buffaloes were used. They were randomly assigned into two groups (Non Shade Group – NS, and Shade Group – SG). All animals were kept under rotational grazing: the ones in the NS group (n=10) were maintained in paddocks under a silvopastoral system, shaded by the tree legume Acacia mangium, whereas the ones in the SG (n=10) were kept in paddocks with no shade access. All animals were grass fed with Brachiaria humidicola, and had free access to drinking water and mineral salt. The climate variables: air temperature (AT), relative humidity (RH) and black globe temperature (BGT) were measured on each treatment. The physiological variables studied were: rectal temperature (RT), respiratory rate (RR), heart rate (HR) and body surface temperature (BST). They were measured in the morning (7h00) and in the afternoon (13h00). Blood sampling, aiming erythrogram, leukocyte count, and the quantitative determination of cortisol, triiodothyronine (T3) and thyroxine (T4), was carried out at the time of the highest temperature in the region (13h00). Three distinct climatic periods of the year were considered: rainy (January to April), transition (May to July) and less rainy (August to December). Analysis of variance showed that there were significant differences (P<0.05) in the AT, temperature humidity index (THI), and black globe humidity index (BGHI) between the distinct periods of the day and between groups. The highest rates were observed in the afternoon in the NS group. The highest RH values were observed during the rainy period. There were statistical differences (P<0.05) in RH between the periods of the day, and the highest values were measured in the morning. Results of analysis of variance for the physiological parameters RT, BST, RR and HR revealed that there were significant differences between the periods of the day and groups, and the values observed in group SS, during the afternoon, were higher (P<0.05) than the ones during the morning. Regarding the hematologic data, the leukocytes count was influenced by the periods of the year and treatments (P<0.05). During the rainy periods, the SG group presented the highest values. In the less rainy and transition periods, the highest values were observed in the NS group. The erythrocytes count was influenced (P<0.05) by the treatments, and the NS group showed the highest values in the less rainy period. Hemoglobin contents were not influenced by the treatments, however they were influenced by the periods of the year, and the highest levels (P <0.05) were observed during the transition and less rainy periods. Regarding the hormones, cortisol was influenced by the treatments (P<0.05), and the NS group showed the highest values. The highest mean rates of cortisol were reported during the rainy and less rainy periods of the year (P<0.05), and the transition period presented the lowest cortisol values. The highest average levels of T3 and T4 were recorded during the rainy period (P<0.05). RT, BST and RR presented a significant and positive (P<0.01) correlation with AT, THI and BGHI, and a negative correlation with RH. These correlations were higher during the less rainy period. HR showed low, but relevant and positive (P<0.01) correlations with AT, THI and BGHI during the two other periods, and significant and negative (P<0.05) correlation with RH only in the rainy period. Leukocytes, erythrocytes and the globular volume did not correlate with AT, RH and BGHI. Only hemoglobin presented a significant and negative (P<0.05) correlation with RH. Cortisol did not correlate with AT, RH and BGHI. T3 and T4 correlated negatively with AT and BGHI, and positively with RH. We concluded that regardless of the season, Murrah buffaloes are subject to a hostile environment, and that the less rainy period is the most conducive to cause heat stress. The transition period caused less impact on the hormonal variables. It can be considered as the period with the best thermal comfort. Forestation of pasture areas is sufficient to increase comfort and consequently improve the productive performance of the animals, especially during the afternoon. / Esta tese avaliou os efeitos do estresse térmico nas respostas fisiológicas, hematológicas e hormonais de búfalas, criadas ao sol e à sombra, na Unidade de Pesquisa Animal “Senador Álvaro Adolpho” (01°.26’.03” S e 48°.26’.03” W), Embrapa Amazônia Oriental, em Belém, Pará, em condições tropicais quentes e úmidas. Foram utilizadas 20 búfalas da raça Murrah, distribuídas de modo inteiramente casualizado, em dois grupos (grupo Sem Sombra - SS e grupo Com Sombra - CS). Todos os animais permaneceram em pastejo rotacionado, sendo os do grupo CS (n=10) mantidos em piquetes de sistema silvipastoril, sombreados pela leguminosa Acacia mangium e os do grupo SS (n=10), mantidos em piquetes sem acesso à sombra. A alimentação foi a pasto, com a gramínea quicuio-da-amazônia (Brachiaria humidicola), com acesso à água para beber e sal mineral ad libitum. As variáveis climáticas, temperatura do ar (TA), umidade relativa do ar (UR) e temperatura de globo negro, foram obtidas no microclima de cada tratamento. As variáveis fisiológicas estudadas foram: temperatura retal (TR), frequência respiratória (FR), frequência cardíaca (FC) e temperatura da superfície corporal (TSC), as quais foram aferidas nos turnos da manhã (7h00) e da tarde (13h00). As colheitas de sangue para realização do eritrograma, do número total de leucócitos e para determinação quantitativa de cortisol, triiodotironina (T3) e tiroxina (T4) foram realizadas no horário de pico de temperatura ambiente local (13h00). Foram considerados os períodos: mais chuvoso (janeiro a abril), de transição (maio a julho) e menos chuvoso (agosto a dezembro). Através da análise de variância foram constatadas diferenças significativas (P<0,05) da TA, índice de temperatura e umidade (ITU) e Índice de temperatura de globo e umidade (ITGU), entre os turnos e grupos, sendo mais elevados no período da tarde e no grupo SS. Os maiores valores de UR ocorreram no período mais chuvoso do ano, com diferenças estatísticas (P<0,05) entre os turnos, com valores superiores pela manhã. Resultados da análise de variância das variáveis fisiológicas TR, TSC, FR e FC revelaram diferenças significativas entre os turnos e grupos, com valores superiores no turno da tarde e grupo SS (P<0,05). No que se refere aos dados hematológicos, o número de leucócitos sofreu influência dos períodos do ano e tratamentos (P<0,05). No período mais chuvoso, o grupo CS apresentou valores superiores, enquanto nos períodos de transição e menos chuvoso, os maiores valores foram do grupo SS. Os valores de hemácias sofreram influência apenas dos tratamentos (P<0,05), com valores mais elevados no grupo SS, durante o período menos chuvoso do ano. O teor de hemoglobina sofreu influência somente nos períodos de transição e menos chuvoso, com níveis mais elevados (P<0,05). Em relação aos resultados hormonais, o cortisol sofreu influência dos tratamentos e períodos (P<0,05), com valores mais altos no grupo SS e períodos mais e menos chuvosos (P<0,05), enquanto que no período de transição foram observados os menores valores. As médias mais elevadas de T3 e T4 foram registradas no período mais chuvoso (P<0,05). A TR, TSC e FR apresentaram correlações significativas (P<0,01) e positivas com a TA, ITU e ITGU, e negativas com a UR, as quais foram mais elevadas no período menos chuvoso. A FC, nos dois períodos do ano, apresentou correlações baixas, porém altamente significativas (P<0,01) e positivas, com a TA, ITU e ITGU, e significativa e negativa (P<0,05), com a UR, somente no período mais chuvoso do ano. Os leucócitos, hemácias e o volume globular não se correlacionaram com a TA, UR e ITGU. Somente a hemoglobina teve correlação significativa e negativa (P<0,05), com a UR. O cortisol não se correlacionou com a TA, UR e ITGU. O T3 e T4 se correlacionaram, negativamente, com a TA e ITGU, e positivamente, com a UR. Conclui-se que independente do período do ano, as búfalas Murrah estão sujeitas a ambiente hostil, com o período menos chuvoso considerado como o mais propício a provocar estresse térmico. O período de transição é o que menos causou impacto sobre as variáveis hormonais, e pode ser considerado de melhor conforto térmico. A arborização da pastagem é eficiente para melhorar o conforto e, consequentemente, o desempenho produtivo dos animais, principalmente no turno da tarde.
94

Efeito da cabergolina no adenoma hipofisário clinicamente não funcionante e correlação dos polimorfismos do gene do receptor do glicocorticoide e da proteína AIP nos corticotropinomas

Garcia, Érica Correia 06 July 2017 (has links)
Tese (doutorado)—Universidade de Brasília, Faculdade de Ciências da Saúde, Programa de Pós-Graduação em Ciências da Saúde, 2017. / Texto parcialmente liberado pelo autor. Conteúdo restrito: Capítulos 3. Tumor Hipofisário Secretor de ACTH e 4. Conclusão. / Submitted by Raquel Almeida (raquel.df13@gmail.com) on 2017-10-13T22:09:03Z No. of bitstreams: 1 2017_ÉricaCorreiaGarcia_PARCIAL.pdf: 4999810 bytes, checksum: 1e48f622a45014d1f4944cae3fc418a6 (MD5) / Rejected by Raquel Viana (raquelviana@bce.unb.br), reason: Bom dia, Por favor, adicione os campos resumo e abstract. Atenciosamente, on 2017-10-25T11:50:38Z (GMT) / Submitted by Raquel Almeida (raquel.df13@gmail.com) on 2017-10-25T12:03:26Z No. of bitstreams: 1 2017_ÉricaCorreiaGarcia_PARCIAL.pdf: 3896393 bytes, checksum: 8f2ea3d14281ff58845dae0c00d72b9d (MD5) / Approved for entry into archive by Raquel Viana (raquelviana@bce.unb.br) on 2017-10-25T14:44:42Z (GMT) No. of bitstreams: 1 2017_ÉricaCorreiaGarcia_PARCIAL.pdf: 3896393 bytes, checksum: 8f2ea3d14281ff58845dae0c00d72b9d (MD5) / Made available in DSpace on 2017-10-25T14:44:42Z (GMT). No. of bitstreams: 1 2017_ÉricaCorreiaGarcia_PARCIAL.pdf: 3896393 bytes, checksum: 8f2ea3d14281ff58845dae0c00d72b9d (MD5) Previous issue date: 2017-10-24 / A abordagem das doenças hipotálamo-hipofisárias representa um desafio na endocrinologia. Em geral, as doenças que envolvem a hipófise possuem elevada morbidade, taxas de mortalidade acima do observado na população geral e propedêutica diagnóstica e terapêutica complexas. Uma melhor compreensão dos mecanismos envolvidos na patogênese dessas condições certamente é um caminho para o desenvolvimento de alternativas terapêuticas nesse contexto. No presente estudo, investigamos a eficácia de uma modalidade de tratamento medicamentoso para o adenoma clinicamente não funcionante (ACNF), e analisamos aspectos genéticos em correlação com a tumorigênese e fenótipo, em pacientes portadores de corticotropinomas - doença de Cushing (DC). Na investigação do ACNF, avaliamos a eficácia da cabergolina (2mg/semana) no tratamento desses tumores em um acompanhamento de curto prazo (6 meses). Dezenove pacientes (10 homens e 9 mulheres) foram submetidos ao tratamento no Hospital Universitário de Brasília (HUB). Onze desses tinham realizado cirurgia transesfenoidal previamente e 8 deles não tinham sido submetidos a nenhum procedimento. Mais da metade (57,89%) dos pacientes tiveram progressão tumoral no último ano antes do início da cabergolina. Após o uso dessa medicação por 6 meses, apenas 21% apresentaram aumento do volume tumoral. Houve redução do volume inicial do tumor em 78,5% dos pacientes (redução significativa, acima de 25%, em 31,5% e redução de pelo menos 10% em 47% dos pacientes). O estudo da doença de Cushing incluiu 53 pacientes acompanhados no HUB, que foram investigados para 2 genes (do receptor de glicocorticoide - GR e da proteína de ligação ao receptor do hidrocarboneto de arila - AIP). Há evidências de que polimorfismos no gene GR levam à alteração do funcionamento normal do eixo hipotálamo-hipófise-adrenal (HHA) e à vulnerabilidade para distúrbios psiquiátricos na população geral. Como a doença de Cushing é amplamente associada aos diversos transtornos psiquiátricos, e cursa essencialmente com hipersecreção crônica de glicocorticoides, uma melhor compreensão dos mecanismos genéticos envolvidos na expressão fenotípica dessa doença pode contribuir, no futuro, para uma melhor condução desses pacientes. Foram investigados os polimorfismos rs6190 (R23K) e rs41423247 (BclI). O polimorfismo R53K do gene GR não foi encontrado entre os 53 pacientes, entretanto o polimorfismo BclI foi encontrado em alta frequência nessa amostra. O grupo com distúrbio psiquiátrico apresentou BclI em homozigose significativamente maior que o grupo controle (45% e 8%, respectivamente). Mutações no gene AIP, por sua vez, foram demonstradas como causadoras do adenoma hipofisário familiar isolado (FIPA), e têm sido descritas em pacientes com tumores hipofisários esporádicos, principalmente nos tumores secretores de hormônio do crescimento ou de prolactina. Na doença de Cushing, a prevalência de mutações nesse gene é baixa. Avaliamos o genótipo do AIP em pacientes portadores de corticotropinomas. Em consonância com os dados da literatura, nenhuma mutação foi encontrada na nossa amostra. Entretanto, o que despertou interesse foi a alta prevalência do polimorfismo localizado no exon 1 desse gene (rs139459091, variante proteica R9Q) e a presença da variante K201*. Futuras investigações incluindo um número maior de pacientes, bem como a realização de estudos funcionais, são necessárias para a compreensão da real importância desses achados. A investigação do uso cabergolina nos ACNF foi animadora (redução tumoral com essa medicação), bem como o estudo da correlação dos aspectos genéticos na expressão fenotípica dos adenomas hipofisários (o polimorfismo do gene GR, BclI em homozigose, foi estatisticamente mais significativo na DC). Já em relação à pesquisa sobre a tumorigênese na DC, mais estudos são necessários para estabelecer sua relação com o gene da proteína AIP. / The approach of hypothalamic-pituitary diseases represents a challenge in endocrinology. In general, pathologies involving the pituitary have high morbidity, mortality rates above what is observed in the general population, and complex diagnostic and therapeutic. A better understanding of the mechanisms involved in the pathogenesis of these conditions is certainly a pathway for the development of therapeutic alternatives in this context. In the present study, we investigated the efficacy of a drug treatment modality for nonfunctioning pituitary adenoma (NFPA), and analyzed genetic aspects in correlation with tumorigenesis and phenotype in patients with corticotropinomas - Cushing's disease (CD). In the investigation of the NFPA, we evaluated the efficacy of cabergoline (2mg / week) in the treatment of these tumors in a short-term follow-up (6 months). Nineteen patients (10 men and 9 women) underwent treatment at the Hospital Universitário de Brasília (HUB). Eleven of these had undergone transsphenoidal surgery (TSS) previously and 8 of them had undergone no procedure. 57.89% of the patients had tumor progression in the last year before the onset of cabergoline. After the use of this medication for 6 months, only 21% presented increased tumor volume. There was a reduction of the initial tumor volume in 78.5% of patients (significant reduction, above 25%, in 31.5% and reduction of at least 10% in 47% of patients). The Cushing's disease study included 53 patients matched in HUB and 2 genes were investigated (the glucocorticoid receptor gene - GR and the aryl hydrocarbon receptor binding protein gene - AIP). There is evidence that polymorphisms in the GR gene lead to vulnerability to psychiatric disorders in the general population. As Cushing's disease is extensively associated with various psychiatric disorders, and its signs and symptoms are a consequence of the chronic hypersecretion of glucocorticoids, a better understanding of the genetic mechanisms involved in the phenotypic expression of this disease may contribute, in the future, to a better conduction of these patients. The polymorphisms rs6190 (R23K) and rs41423247 (BclI) were investigated. The R23K polymorphism of the GR gene was not found among the 53 patients, however the BclI polymorphism was found at high frequency in this sample. The group with psychiatric disorder presented BclI in homozygosis significantly higher than the control group (45% and 8%, respectively). Mutations in the AIP gene have been shown to cause familial isolated pituitary adenoma (FIPA), and have been described in patients with sporadic pituitary tumors, especially in growth hormone or prolactin secreting tumors. In Cushing's disease, the prevalence of mutations in this gene is low. We evaluated the AIP genotype in patients with corticotropinomas. In agreement with the literature data, no mutation was found in our sample. However, what aroused interest was the high prevalence of the polymorphism located in exon 1 of this gene (rs139459091, variant protein R9Q) and the presence of the variant K201 *. Future investigations including a larger number of patients, as well as conducting functional studies, are necessary to understand the real importance of these findings. The investigation of cabergoline use in ACNF was encouraging (tumor reduction with this medication), as well as the study of genetic aspects in the phenotypic expression of pituitary adenomas (BclI homozygous polymorphism of the GR gene was statistically more significant in DC). Regarding the research on tumorigenesis in DC, more studies are needed to establish its relationship with the AIP protein gene.
95

The Effects of Father Involvement in Adolescence on Cortisol Reactivity in Young Adulthood: The Mediating Role of Perceived Mattering

January 2015 (has links)
abstract: Research suggests that early family relationships have critical influences on later physical and psychological health, but most studies have focused on the influence of mothers ignoring the unique impacts of fathers. One mechanism by which families may transmit risk is by repeated activation of the hypothalamic-pituitary-adrenal (HPA) axis in the short-term that leads to adult neurobiological dysregulaton, evident in hyper- or hypo-cortisol levels. Using 218 father-child dyads from the Parent and Youth Study (PAYS), the current study investigated whether father involvement in adolescence predicted youth cortisol AUCg and reactivity to a stress task in young adulthood, and whether this relation was mediated by youth perceptions of mattering to their fathers in adolescence. Results revealed that higher father-reported father involvement predicted lower cortisol AUCg in youth when mattering was included in the model, although father involvement was not a statistically significant predictor of AUCg or cortisol reactivity when mattering was not included. Additionally, children who reported higher father involvement also reported higher feelings of mattering, but this association was only statistically significant for girls and European American youth. Youth feelings of mattering did not predict their cortisol reactivity or AUCg in young adulthood. Results suggest that future research should include fathers when investigating the effects of family relationships on youth psychophysiological development. / Dissertation/Thesis / Masters Thesis Psychology 2015
96

Respostas zootécnicas, fisiológicas e comportamentais de ovelhas Santa Inês submetidas a diferentes fatores de estresse do início da lactação até o desmame

Rodrigues, Alice Deléo [UNESP] 26 February 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-26Bitstream added on 2014-06-13T20:37:12Z : No. of bitstreams: 1 rodrigues_ad_me_jabo.pdf: 1026288 bytes, checksum: c204bcf0ab313f4e57fc58d1ffb4ccf2 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A ovinocultura tem se destacado no agronegócio brasileiro, principalmente associada à utilização da raça Santa Inês como raça materna, assim a escolha de animais mais produtivos é fundamental para o sucesso do empreendimento. Com o objetivo de verificar se ovelhas da raça Santa Inês menos suscetíveis às diferentes situações de manejo consideradas estressantes seriam as mais produtivas conduziu-se experimento com 48 animais, avaliados do nascimento dos cordeiros até um mês após desmame. Foram realizadas três imposições de estresse: administração de ACTH, desmame e primeira ordenha. Para administração de ACTH e estresse de primeira ordenha, valores mais altos nos níveis plasmáticos de cortisol foram verificados cerca de uma hora após a imposição dos fatores de estresse e, cerca de seis horas depois, os níveis basais foram restabelecidos, porém, os níveis de cortisol após o desmame continuaram elevados até seis horas após sua imposição. As frequências dos comportamentos LIMP, ING e MAMAR foram influenciadas negativamente pelos maiores níveis de cortisol verificados no desafio “ACTH”. A produção de leite teve pico na segunda quinzena de lactação e os valores percentuais de extrato seco, gordura, lactose, minerais e proteína aumentaram ao longo do período. Durante o período de aleitamento dos cordeiros, a produção de leite das ovelhas foi influenciada pelo maior nível de cortisol plasmático verificado no desafio “ACTH”. Animais com níveis plasmáticos de cortisol mais altos apresentaram resultados inferiores aos de animais com níveis mais baixos / The sheep breeding is having a gain in Brazilian agribusiness mainly the one associated to Santa Ines breed as maternal line, and the choice of more productive animals is fundamental to the business success. The aim of this research was to verify if Santa Ines ewes less susceptible to the different management conditions, considered as stress factors, would be more productive. The experiment was conducted with 48 animals evaluated since the lambs birth up to one month after the wean of the lambs. Three conditions of stress were imposed: standard physiological stress through administration of ACTH, wean and first milking. The ACTH administration and first milking stress induced higher values of plasmatic cortisol one hour after application of stress, and six hours later, the basal levels were re-established. The cortisol levels after wean remained high six hours after stress imposition. The frequencies of behaviors clean up, ingestion and suckle were influenced negatively by the high levels of cortisol verified on the ACTH challenge. The milk production presented one peak in the second fortnight of lactation and the percentual values of dry extract, fat, lactose, minerals and protein increased during the period. During the lambing nursing period, the milk production was influenced by the highest level of plasmatic cortisol, verified in the ACTH stress. Ewes with high levels of plasmatic cortisol present lower results than the animals with smaller cortisol
97

Cultural Factors and the HPA Axis Stress Response Among Latino Students Transitioning to College

January 2018 (has links)
abstract: A record number of Latino students are enrolling in higher education in the U.S., but as a group Latinos are the least likely to complete a bachelor’s degree. Cultural factors theoretically contribute to Latino students’ success, including orientation toward ethnic heritage and mainstream cultures (i.e., dual cultural adaptation), feeling comfortable navigating two cultural contexts (i.e., biculturalism), and the degree of fit between students’ cultural backgrounds and the cultural landscapes of educational institutions (i.e., cultural congruity). In a two-part study, these cultural factors were examined in relation to the hypothalamic-pituitary-adrenal (HPA) axis stress response (indexed by salivary cortisol), a physiological mechanism that may underlie how psychosocial stress influences academic achievement and health. First, Latino students’ cortisol responses to stress were estimated in their daily lives prior to college using ecological momentary assessment (N = 206; 64.6% female; Mage = 18.10). Results from three-level growth models indicated that cortisol levels were lower following greater perceived stress than usual for students endorsing greater Latino cultural values (e.g., familism), compared to students endorsing average or below-average levels of these values. Second, cortisol and subjective responses to a standard public speaking stress task were examined in a subsample of these same students in their first semester of college (N = 84; 63.1% female). In an experimental design, viewing a brief video prior to the stress task conveying the university’s commitment to cultural diversity and inclusion (compared to a generic campus tour) reduced cortisol reactivity and negative affect for students with greater Latino cultural values, and also reduced post-task cortisol levels for students with greater mainstream U.S. cultural values (e.g., competition). These findings join the growing science of culture and biology interplay, while also informing initiatives to support first-year Latino students and the universities that serve them. / Dissertation/Thesis / Doctoral Dissertation Psychology 2018
98

Estudo da associação entre aptidão física relacionada à saúde e ritmo diurno de cortisol e sulfato de dehidroepiandrosterona em idosos

Vaz, Fabiane de Castro 26 August 2013 (has links)
Dissertação (mestrado)—Universidade de Brasília, Faculdade de Ciências da Saúde, Programa de Pós-Graduação em Ciências da Saúde, 2013. / Submitted by Albânia Cézar de Melo (albania@bce.unb.br) on 2013-11-19T15:12:48Z No. of bitstreams: 1 2013_FabianeCastroVaz.PDF: 1966793 bytes, checksum: 7c2b6d3bcdd555ccc24735ee732f0f66 (MD5) / Approved for entry into archive by Luanna Maia(luanna@bce.unb.br) on 2013-11-27T13:15:07Z (GMT) No. of bitstreams: 1 2013_FabianeCastroVaz.PDF: 1966793 bytes, checksum: 7c2b6d3bcdd555ccc24735ee732f0f66 (MD5) / Made available in DSpace on 2013-11-27T13:15:07Z (GMT). No. of bitstreams: 1 2013_FabianeCastroVaz.PDF: 1966793 bytes, checksum: 7c2b6d3bcdd555ccc24735ee732f0f66 (MD5) / INTRODUÇÃO: Distúrbios neuroendócrinos têm sido reconhecidos como manifestações de fragilidade no idoso. Alterações na capacidade física funcional também podem estar associadas com alterações no sistema endócrino. Estudos apontam relação inversa entre níveis de cortisol diurno com o desempenho físico em idosos. A elevação prolongada de níveis de cortisol salivar (Cs) e a redução excessiva das concentrações de Sulfato de Dehidroepiandrosterona (SDHEA) estão associadas a um risco maior de atrofia muscular e déficits de força, comumente observados no envelhecimento. OBJETIVO: Avaliar associações entre a capacidade funcional e o número de passos diários de idosos com o ritmo diurno de cortisol e concentração de SDHEA, em idosos autônomos, não frágeis, de ambos os sexos. MÉTODOS: Foram avaliados 69 idosos, entre 60 e 84 anos de idade, de ambos os sexos. O grupo foi constituído por 45 mulheres (65,2%) e 24 homens (34,7%) com 2IMC mediano de 27,3 (19,1 - 38,6) kg/m. O nível de atividade foi avaliado por meio do número de passos, medidos por pedômetro usado em 3 dias úteis consecutivos. Os indivíduos foram considerados ativos quando a média de passos diários foi ≥7.000 passos e insuficientemente ativos quando <7.000 passos. Procedeu-se à coleta de cortisol salivar (Cs) 30 minutos após acordar, às 11, 17 e 21 horas e antes de dormir, além de uma dosagem sanguínea de concentração plasmática de SDHEA. A capacidade funcional foi avaliada pelo Teste Sentar Levantar (TSL), Apoio Unipodálico (TAU), Timed Up and Go (TUG), Teste de 1RM (T1RM) e Teste de Caminhada de 6min (TC6). No terceiro dia de uso do pedômetro foi feita a coleta domiciliar do Cs. No 4º dia foi realizada, em laboratório, a coleta sanguínea de SDHEA e entrega dos tubos Salivettes® para análise do Cs. No 5° dia foi realizada avaliação da capacidade funcional. Dada distribuição não normal de diferentes variáveis (teste de Shapiro-Wilk), empregaram-se estatísticas não paramétricas, usando-se a correlação de Spearman e o teste de Mann-Whitney quando aplicável, sempre ao nível de 5%. Procedeu-se à correção para a idade, aplicando-se regressão logística binária. RESULTADOS: 41 indivíduos (59,4%) foram considerados insuficientemente ativos, e 28 (40,6%) ativos. Idosos considerados ativos apresentaram melhor equilíbrio e maior desempenho no Teste de Força para Extensão de Joelhos (T1RM) (p=0,05), quando comparados com os idosos inativos. Observou-se que aqueles com maior Cs11h e maior AUC acima da mediana, apresentaram pior desempenho no T1RM, (p<0,05). O grupo com menor SDHEA apresentou pior desempenho no TC6 (p=0,03). CONCLUSÃO: Idosos ativos que caminham mais demonstram maiores índices de capacidade funcional, maior força muscular e melhor equilíbrio. Observou-se associação inversa entre indicadores de secreção diurna de cortisol e o desempenho físico, especialmente com a força de membros inferiores, além de evidente relação direta entre o grau de atividade física e concentração plasmática de SDHEA. ______________________________________________________________________________ ABSTRACT / NTRODUCTION: Neuroendocrine disturbance has been identified among elderly people as a fragility manifestation. Alterations in functional capacity may also be associated to changes in endocrine system. There are studies that indicate an inverse relation between diurnal cortisol levels and aged people physical performance. The extended elevation of the levels of salivary cortisol (sC) and the excessive reduction of dehydroepiandrosterone (DHEA) are associated to a greater risk of muscle atrophy and strength deficit, manifestations frequently observed through the aging process. OBJECTIVE: The objective of this study was to evaluate the relations between functional capacity and the amount of aged people’s daily steps with diurnal cortisol rhythm and DHEA concentration, in non-fragile, autonomous, elderly persons from both genders. METHODS: A total of 69 elderly people aged 60-84 from both genders were evaluated, consisting of 45 women (65.2%) and 24 men (34.7%), with a body mass index median of 27.3 (19.1 – 38.6) kg/m². The activity level was evaluated by number of steps measured by a pedometer used during three consecutive working days. Individuals were considered active when the daily steps mean was ≥7,000 steps and insufficiently active when <7,000 steps. Salivary cortisol was sampled 30min after awakening, at 11 a.m., 5 p.m. and 9 p.m. and before bedtime, in addition to the blood dosage from DHEA plasmatic concentration. The functional capacity was evaluated by the Sitting-Rising Test (SRT), Single-Leg Stance (SLS), Timed Up and Go (TUG), 1RM Test (1RM) e Six Minute Walk Test (6MWT). In the third day of pedometer use, the house collection of the sC was done. In the fourth day, the DHEA blood sample was taken at the laboratory, as well as the delivery of the Salivettes® for salivary cortisol analyses was done. In the fifth day, the evaluation of the functional capacity was carried out. Considering that the several variables had a non-normal distribution (Shapiro-Wilk test), non-parametric statistics was employed, using the Spearman correlation test and the Mann-Whitney test when applicable, always at 5% level. Correlation for age was effected using the binary logistic regression. RESULTS: A total of 41 individuals (59.4%) were classified as insufficiently active, and 28 as active (40.6%). Elderly people classified as active showed better balance and better performance in the One-Repetition Maximum Test (1RM) (p=0,05) when compared to inactive elderly people. It was found that those with >sC11h and >AUC above the median showed worse performance in 1RM Test (p<0,05). The group with the smallest DHEA showed the worst performance in the 6MWT (p=0,03). CONCLUSION: Active elderly people who walk more show better functional capacity levels, greater muscular strength and better balance. An inverse association between diurnal cortisol secretion indicators and physical performance was observed, mainly with respect to the strength of the lower limbs, in addition to a manifest direct relation between the physical activity level and the plasmatic concentration of DHEA.
99

Estresse em estudantes pre-vestibulandos / Stress in senior students

Rolim, Maria Candida Camargo 15 February 2007 (has links)
Orientadores: Regina Celia Spadari-Bratfisch, Dora Maria Grassi-Kassisse / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-09T22:40:48Z (GMT). No. of bitstreams: 1 Rolim_MariaCandidaCamargo_M.pdf: 1802242 bytes, checksum: 4dd8205a065b2183624a2ba1a26b6c6c (MD5) Previous issue date: 2007 / Resumo: Estresse é a resposta do organismo a situações que representam algum tipo de ameaça à sua integridade. Acredita-se que estudantes que prestam o vestibular enfrentam um período de alto índice de estresse psicossocial que perdura durante todo o ano. Neste estudo avaliamos o índice de estresse por meio da concentração salivar de cortisol (CSC) e da ocorrência de sinais e sintomas de estresse (questionário de estresse percebido, QEP). Estes indicadores foram avaliados em alunos de um curso pré-vestibular e em alunos do segundo ano do ensino médio. A coleta de material foi realizada mensalmente ao longo do ano letivo e no dia do vestibular. Os resultados mostram que, em vestibulandos, a CSC é significativamente mais alta em setembro, mês de inscrições, quando comparada aos outros meses do ano e ao dia do exame vestibular. Neste dia, também há um aumento na CSC às 12 e às 18h, quando comparado ao mesmo horário em agosto e outubro. O QEP não variou ao longo do ano. Não houve correlação entre os indicadores fisiológicos e psicológicos de estresse, assim como entre a concentração salivar de cortisol em novembro e o índice de aprovação no exame vestibular. Em alunos do ensino médio, a CSC e o QEP não sofreram alterações significativas ao longo do ano. Nós concluímos que vestibulandos são submetidos a alto índice de estresse ao longo do ano letivo, com aumento de indicadores fisiológicos de estresse nos meses de inscrição e no momento do exame e que a CSC pode ser um indicador confiável do grau de ativação do eixo hipotála-mohipófise-adrenal e, conseqüentemente, do índice de estresse / Abstract: Stress is defined as the organism response to a variety of potentially dangerous stimulus. During the year preparing to apply for the public universities, students have enormous intellectual work and psychosocial stress including several hours of daily study. The aim of this work is to evaluate stress through the salivary cortisol levels (SC) and the ¿Perceived Stress Questionnaire¿ (PS). These indicators of stress levels were determined in volunteer students who are preparing to start university (US) and pupils in the second year of high school (HS). Saliva samples were collected once a month during the scholar year and also on the day of the exam. The SC was higher in September, when US have to decide on a career, than those seen in other months or on the day of the exam. The SC increased in the exam day at 12:00 and 18:00 o¿clock compared to August and October. The PS did not vary during the year. There was no correlation either between physiological and psychological stress or between the SC in November and the success in the admission exams. The SC and PS did not show statistical changes during the HS year. We conclude that the SC of US oscillated during the year indicating that these students are under high levels of stress, that are even higher in the period of registration and in the day of the exam, and that the SC is a good indicator of the hypothalamus-pituitary-adrenal activation level and, therefore, of stress / Mestrado / Fisiologia / Mestre em Biologia Funcional e Molecular
100

Avaliação do eixo hipotálamo-hipófise-adrenal medida por cortisol salivar em mulheres na pós-menopausa inicial: efeito da reposição hormonal

MARQUES, Thyciara Fontenele 31 January 2012 (has links)
Submitted by João Arthur Martins (joao.arthur@ufpe.br) on 2015-04-08T17:59:44Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TFM.pdf: 649734 bytes, checksum: 28723ca76fa40f2c9caa3d4d758a7caa (MD5) / Made available in DSpace on 2015-04-08T17:59:44Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TFM.pdf: 649734 bytes, checksum: 28723ca76fa40f2c9caa3d4d758a7caa (MD5) Previous issue date: 2012 / Avaliar a função do eixo hipotálamo-hipófise-adrenal, através do cortisol salivar da meia-noite, e sua relação com parâmetros clínicos e laboratoriais em mulheres na pós-menopausa inicial, antes e após seis meses do uso da terapia hormonal (TH). Métodos: Ensaio clínico aberto realizado em mulheres nos primeiros cinco anos de menopausa com indicação para o uso da TH. Foram avaliados os níveis pressóricos, a medida da circunferência abdominal (CA), o índice de massa corpórea (IMC), perfil lipídico, perfil glicêmico e dosagem do cortisol salivar da meia-noite antes e após seis meses de uso diário de 17-β-estradiol 1g e drospirenona 2mg. Resultados: Dezenove pacientes concluíram o estudo. Observamos um declínio dos níveis de cortisol salivar ao longo do tratamento, porém, sem relevância estatística (p=0,488). A medida da CA apresentou redução significativa (90,21 cm vs 88,53 cm) com p=0,011, dado não observado com a média do IMC (27,55 kg/m2 vs 27,26 kg/m2; p=0,152). A média dos níveis de pressão arterial sistólica, colesterol total, glicemia de jejum (GJ) e lipoproteína de baixa densidade (LDL) apresentaram declínio estatisticamente significante após os seis meses de tratamento. Houve uma correlação entre os níveis de cortisol e pressão arterial sistólica, diastólica e GJ, antes do uso da TH, que não se manteve após o período de tratamento. Conclusão: O uso da TH por seis meses não foi capaz de promover alteração nos níveis de cortisol salivar à meia noite, mas foi responsável por uma redução significativa na CA, pressão arterial sistólica, níveis de LDL e GJ.

Page generated in 0.0395 seconds