Diss.--Sozialwissenschaften--Tübigen--Eberhard-Karls-Universität, 1999. / Bibliogr. p. 157-165.

Diss.--Fachbereich Sozialwissenschaften--Mainz--Johannes Gutenberg-Universität, 1994. / Résumé. Bibliogr. p. 173-188.

Cette thèse a eu pour but d’étudier l’augmentation de la sensibilité des cellules tumorales mammaires aux agents anticancéreux par les acides gras polyinsaturés oméga 3 (AGPI n-3). Nous avons montré que cet effet est lié à une augmentation du captage cellulaire et à une modification de la distribution et de la métabolisation intracellulaire de la mitoxantrone. La modification de la métabolisation intracellulaire de l’agent anticancéreux par les AGPI n-3 impliquant la voie du stress oxydant, l’étude de cette voie a montré que l’effet sensibilisant des AGPI n-3 aux anthracyclines était associé à une augmentation de la peroxydation lipidique, conséquence de la diminution de la glutathion peroxydase, enzyme antioxydante importante. Les AGPI n-3 peuvent également augmenter la sensibilité de tumeurs mammaires de rats aux taxanes. La modification de la répartition des compartiments vasculaires (micro-, et macro-vascularisation) par les AGPI n-3 semble être impliquée dans cet effet. Les AGPI n-3 augmentent donc l’efficacité des agents anticancéreux et cet effet implique la voie du stress oxydant et la vascularisation tumorale. / The aim of this thesis was to investigate the mechanisms of mammary tumor sensitization to anticancer drugs by omega 3 polyunsaturated fatty acid (n-3 PUFA). We showed that the increase in tumor cell sensitivity to mitoxantrone was associated with an enhancement in mitoxantrone uptake and a modification of the mitoxantrone distribution and metabolization within the cells. As we found that these last results involved oxidative stress, we examined the relation between chemosensitization by n-3 PUFA and tumor cells oxidative status. We found that n-3 PUFA decreased the activity of an anti-oxidant enzyme, the glutathione peroxidase, leading to an enhancement in lipid peroxidation. Finally, we showed in vivo that alterations of the vascular compartment organization (micro-, medium- and macro-vascularization) may occur for the effect of n-3 PUFA increasing taxanes efficacy. This thesis brought a major contribution to better understand the mechanisms involved in the chemosensitization by n-3 PUFA, such as tumor oxidative stress and tumor vascularization, and pave the way for new preclinical clinical studies dealing with the enhancement of anticancer therapy by n-3 PUFA.

The thesis explored the role of metacognition, worry and rumination in stress and recovery and is grounded in the Self-Regulatory Executive (S-REF: Wells and Matthews, 1994) model. The concept of recovery is difficult to define and therefore, three definitions of recovery were used to ensure this concept was evaluated across a variety of contexts. A multi-method approach was used that incorporated both experimental and quasi-experimental designs, which included a review of the existing literature, experimental manipulations, cross-sectional and longitudinal designs. Data included psychological and physiological outcome measures that were evaluated in analogue and clinical samples. Chapters 1 and 2 provide an overview of the thesis and the methodologies used throughout. Chapter 3 (study 1) includes a systematic review of the literature on the role of metacognition in bouncing back from stress, which provides a backdrop for the thesis. The results highlighted that two aspects of metacognition (metacognitive beliefs and coping strategies) were found to be related to factors indicative of resilience. In particular, metacognitive beliefs were positively associated with increased stress levels, and worry and punishment were associated with increased stress symptoms. Chapters 4 and 5 were experimental manipulations of strategies central to the metacognitive model (worry and rumination) and metacognitive beliefs (e.g., thought importance), and evaluated their effects on recovery from stress. Thinking styles and metacognitive beliefs delayed recovery from psychological stress with some evidence of different impacts on psychological and physiological indices. Subsequent to this Chapter 6 focused on further validation of the Detached Mindfulness Questionnaire and confirmed the five factor solution of the scale. Chapter 7 evaluated the metacognitive predictors of resilience, psychological distress (anxiety and depression), and clinically defined recovery from stress. Negative metacognitive beliefs and detachment were found to predict resilience such that increased resilience was associated with increased detachment and decreased negative metacognitive beliefs. In addition, negative metacognitive beliefs positively predicted psychological distress two months after initial assessment, while greater detachment positively predicted recovery from psychological distress. Finally chapters 8 and 9 evaluated the role of metacognition in recovery from stress in clinical populations (individuals receiving group metacognitive therapy). Predictors of change in metacognitive therapy were evaluated using SEM, which demonstrated that changes in metacognitive beliefs precede changes in symptoms of distress. Finally, a feasibility study was conducted of two psychological therapies (MCT and MBSR) in treating a transdiagnostic sample. Both treatments were found to be acceptable and feasible, and preliminary evidence indicated that metacognitive therapy may be the more effective intervention. The results produced two broad themes. The first is that metacognitive beliefs and thinking styles impacted on recovery from stress, which was found across populations, settings, and definitions of recovery. The second is that the detachment component of detached mindfulness predicted recovery from stress, such that greater detachment was associated with an increased probability of recovering. Further research is needed to explore the effect of metacognition on additional aspects of recovery. In summary, the thesis supports the idea that metacognition and thinking styles as implicated in the S-REF model play an important role in recovery.

Le développement d'un individu se fait sous l’influence de son patrimoine génétique et de facteurs épigénétiques. Ainsi des perturbations environnementales précoces telles qu’une exposition accrue aux glucocorticoïdes maternels pourraient favoriser et programmer l’émergence de désordres physiologiques et comportementaux à l’age adulte. Chez le rat, un stress prénatal (PRS, stress de contention chronique chez la mère gestante) modifie de manière permanente l’activité de l’axe corticotrope de la descendance, il induit, également, une réduction de la neuroplasticité tout au long de la vie de l’animal ainsi que des perturbations durables sur le plan comportemental. Celles ci seraient associées à des perturbations neurologiques et endocrines similaires à celles observées au cours de la dépression chez l’Homme. BUT DE LA THESE etait de caracteriser le phenotype des rats PRS au niveau des rythmes circadiens (activité locomotrice et cycle veille-sommeil) et la neuroplasticité hippocampique ainsi que d’évaluer la modulation pharmacologique des altérations induites par le PRS à travers deux types d’antidepresseurs. Les rats PRS montrent une avance de phase du rythme circadien d’activité locomotrice ainsi qu’une fragmentation importante du cycle veille sommeil par rapport aux animaux contrôles. De façon générale le PRS induit une réduction de la neurogénèse hippocampique et de la neuroplasticité. Nous avons pu verifier la validité predictive du modèle PRS dans sa réponse aux antidépresseurs. Certaines des alterations comportementales ainsi que toutes les alterations de la plasticité cerebrale que nous avons observées peuvent être réduites par differentes classes d’antidepresseurs.Ces résultats font du modèle de stress prénatal de contention un modèle intéressant de programmation précoce des maladies de l’adulte pour étudier la relation entre un dysfonctionnement de l’axe corticotrope et certaines altérations comportementales et neurologiques. / It is recognized that exposure to an adverse environment during foetal period may have lifelong programming effects on different body functions with a considerable impact on disease susceptibility. The stressors occurring during pregnancy can impair biological and behavioural response to stress during adulthood. Prenatal restraint stress (PRS) in rat is a well-documented model of early stress known to induce long-term neurobiological and behavioural alterations and it is a validated model to study anxiety and depression like-behaviours. This work tries both to better characterise the phenotype of PRS rats in regard to circadian rhythms (locomotor activity and sleep/wake cycle) and hippocampal neuroplasticity and to test the capability of two antidepressants to reverse the alterations induced by PRS.Significant phase advances in circadian rhythms of locomotor activity were observed in PRS rats compared to controls, also after an abrupt shift of L/D cycle. The sleep/wake cycle of PRS was significantly more erratic and fragmented compared to controls. Brain plasticity (hippocampal neurogenesis, mGlu receptors expression, protein expression) was reduced by PRS. However antidepressants treatment was able to reverse the PRS abnormalities and to back to the level of the control group the parameters considered. Those observations both reinforce the idea of a general homeostatic dysfunction in animals exposed to prenatal stressful events that might partially explain some of their abnormal hormonal/behavioural response to stress and could increase the comprehension of the mechanisms underlying the long-term effects of early life manipulations.

La presente investigación tuvo como objetivo determinar la relación entre los niveles de estrés percibido y los estilos de afrontamiento predominantes en una muestra de pacientes con Bulimia Nerviosa. Con dicho fin, se aplicó el Inventario de Trastornos de la Conducta Alimentaria, el Cuestionario de Respuesta al Estrés y el Cuestionario de Estilos de Afrontamiento a 30 pacientes con BN y 30 personas sin el trastorno. Se encontraron diferencias significativas en los niveles de estrés, siendo este mayor en el grupo clínico. Al interior de este se observaron diferencias de acuerdo a la edad y al tiempo de enfermedad. En cuanto afrontamiento, se hallaron diferencias significativas en ambos grupos en el uso de los estilos centrado en el problema y evitativo. Al interior del grupo clínico, se encontraron diferencias de acuerdo a la comorbilidad. Finalmente se obtuvieron correlaciones significativas medianas y grandes entre la BN, el estrés y el afrontamiento. / The aim of this study was to identify the association between stress levels and coping styles in a sample of patients with Bulimia Nervosa. Two groups conformed by 30 patients and 30 non-patients were assessed using the Eating Disorders Inventory (EDI-2), the Stress Response Questionnaire and the Coping Estimation Inventory. Stress levels were significantly greater in the clinical group. Within the clinical group, differences were observed according to age and time course of illness. In terms of coping, significant differences were found in the use of problem-focused and avoidant coping between the groups. Among the clinical group, differences in coping were obtained according to comorbidity. Finally, significant correlations were found between BN symptoms, stress and coping. / Tesis

The present study was undertaken to examine the relationship between perceived personal stress and work productivity. There were 279 respondents who returned the Perceived Stress Scale, Endicott Work Productivity Survey, and demographic data, resulting in a response rate of 69%. The demographic data elicited demographic characteristics, including gender, marital status, and number of children. Seven research questions were asked and the analyses used were correlation and t-tests. The analyses showed the following findings: a relationship was found to exist between stress work productivity; no significant overall differences were found between genders, however, significant differences were found for individual questions; no relationship existed between stress and work productivity based on marital status, or based on having children. Two main conclusions were drawn; (1) when one is under more stress, there is less work productivity, and, (2) women were more stressed and had lower work productivity.

Stress has been found to both facilitate and impair memory depending on the memory phase during which the stressor occurs. Generally, stress has been shown to facilitate memory consolidation and impair retrieval. Research has revealed conflicting findings regarding the effect of stress on encoding. While some studies have demonstrated an impairing effect, others have found a facilitatory effect of stress on memory performance. To explain these findings, researchers have suggested a time-dependent effect of stress on memory. Stress is proposed to facilitate memory for temporally proximate events and impair memory for events occurring after a delay. The current study sought to test this hypothesis. Participants were exposed to a cold pressor stress manipulation then randomly assigned to a delay interval between 0 and 60 minutes long. After the delay, participants learned a series of positive, negative and neutral word pairs, and were given a 24 hour delayed cued recall test. Results demonstrated that a cubic regression model was able to significantly predict memory performance based on delay. However, the results differed depending on the sex of the participants. While female participants displayed the expected increased performance at short delays and decreased performance at 15 to 40 minute delay intervals, male participants displayed increased performance at 20 to 35 minute delay intervals. As discussed, a potential explanation for these findings is that the magnitude, direction and time course of the effect of stress on memory may depend on the perceived severity of the stressor and the extent to which participants experience increase activity in the sympathetic-adrenal-medullary axis, hypothalamic-pituitary-adrenal axis or both.

Orientador: Regina Celia Spadari / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-07-14T00:03:56Z (GMT). No. of bitstreams: 1 Martins_MarliCardoso_M.pdf: 3221775 bytes, checksum: 809e499c474fa4c62483d771cca4381d (MD5) Previous issue date: 1991 / Resumo: Estudos prévios demonstraram que átrios direitos isolados de ratos submetidos ao "stress" apresentam alterações de sensibilidade ao efeito cronotrópico das catecolaminas. Os objetivos deste trabalho são: avaliar a possibilidade de uitilização da técnica de registro da pressão arterial em ratos não anestesiados, para a análise das respostas cronotrópica e pressórica às catecolaminas; descrever as alterações de sensibilidade cardiovascular às catecolaminas em ratos submetidos ao "stress"; caracterizar a participação dos diferentes tipos de adrenoceptores nestas alterações; comparar as alterações observadas "in vivo" com aquelas anteriormente descritas em átrios direitos isolados de ratos submetidos ao "stress". Utilizamos ratos machos, adultos, Wistar. Sob anestesia por éter, as artérias e veias femurais esquerdas de cada animal foram canuladas 24s antes do experimento. O registro da pressão arterial foi obtido conectando-se a cânula arterial a um transdutor de pressão, enquanto o animal permanecia em sua própria gaiola, não anestesiado. A administração dos diferentes farmacos foi realizada através da cânula venosa. Os animais do grupo experimental foram submetidos a 50 min. de natação... O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: Not informed. / Mestrado / Fisiologia / Mestre em Ciências Biológicas

Objective: This study reports the stress related causes of presenteeism amongst South African managers, including the opportunities and challenges of affirmative action. Methods: Data were obtained through the use of a questionnaire administered to all managers in two companies situated in the Gauteng region of South Africa. The survey incorporated the COPSOQ stress scales, Stanford Presenteeism Scale (SPS-6), and an affirmative action scale. Results: Seventy-three percent (62) of the managers responded. Cronbach’s alpha for all scales indicates adequate reliability. There were significant differences in levels of stress between South African managers and those in other countries. High levels of stress are associated with decreased presenteeism. There were significant differences in the means between black and white managers in relation to affirmative action in the South African work environment. Conclusions: Black managers appear to be alienated from feeling responsible for productivity, while white managers appear to work under fear-based motivation due to affirmative action measures imposed in the workplace. / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted