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  • 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.
561

Expression of Borderline Personality Disorder Symptoms across the Ovulatory Cycle: A Multilevel Investigation

Eisenlohr-Moul, Tory A. 01 January 2013 (has links)
Borderline Personality Disorder (BPD) is a disabling condition characterized by chronic emotion dysregulation and behavioral impulsivity. Prospective studies that test proposed mechanisms of within-person change in BPD hold the key to improving symptom predictability and control in this disorder. A small body of evidence suggests that fluctuations in estradiol such as those occurring naturally at ovulation during the monthly female reproductive cycle may increase symptoms in women with BPD (DeSoto et al., 2003). Furthermore, there is preliminary evidence that both self-esteem and feelings of social rejection are highest at ovulation, when estradiol peaks (Durante and Hill, 2009; Eisenlohr-Moul et al., under review). Such feelings have been reliably linked to increases in BPD-related behavior in all individuals (e.g., Twenge et al., 2002). The purpose of this dissertation was to test a cyclical vulnerability model for women with BPD in which ovulatory estradiol shifts are associated with reductions in felt social acceptance, which in turn are associated with increased BPD symptom expression. 40 women, sampled to achieve a flat distribution of BPD symptoms, completed 28 daily diaries online, as well as four 1-hour weekly visits to the laboratory to complete longer assessments and provide saliva samples, which were assayed for estradiol. In addition, participants underwent the Structured Clinical Interview for the Diagnosis of BPD at the end of the study. Results of multilevel models revealed the opposite of the predicted effects of within-person changes in estradiol and their interaction with trait BPD. The data suggest a pattern in which women high in trait BPD show increases in felt acceptance and reductions in BPD symptom expression at higher levels of conception probability and higher-than-usual levels of estradiol. Women low in trait BPD show the opposite pattern in some cases. Several alternative moderators were tested, and results suggest that some risk factors for BPD (e.g., Neuroticism, Sexual Abuse) interact with high trait levels of estradiol to predict greater symptoms. Both average levels of estradiol and monthly fluctuations in estradiol may have relevance for women with BPD. It is recommended that future studies utilize clinical samples and additional physiological measures to further elucidate the mechanisms through which estradiol exerts clinically-relevant change.
562

Identification of Expression and Function of the Glucagon-like Peptide-1 Receptor in Gastrointestinal Smooth Muscle

May, Alexander T 01 January 2017 (has links)
In response to ingestion of nutrients, enteroendocrine L cells secrete the incretin hormone, glucagon-like peptide-1 (GLP-1), to enhance glucose-dependent insulin release. Therapies related to GLP-1 are approved for type 2 diabetes. The GLP-1 receptor (GLP-1R) is expressed in cells of the gastrointestinal tract and elsewhere. In pancreatic beta cells, GLP-1R are coupled to the Gs/cAMP/PKA pathway. The expression and function of GLP-1R in gastrointestinal smooth muscle are not known. Aim. To test the hypothesis that GLP-1 regulates smooth muscle function by acting on GLP-1R expressed on smooth muscle. Methods. Smooth muscle cells (SMC) were isolated and cultured. Expression of GLP-1R mRNA was measured by RT-PCR. Expression of GLP-1R protein was measured by western blot. The effect of GLP-1 (7-36) amide on Gαs activation, cAMP formation, and PKA activity was examined in cultured SMC. The effect of GLP-1 on basal activity and on acetylcholine-induced contraction was measured in intact colon via organ bath. Results. Amplification of GLP-1R mRNA suggested expression of GLP-1R mRNA in mucosal and non-mucosal colon cells, which was confirmed in pure SMC cultures. Similar patterns of protein expression were obtained with western blot. Addition of GLP-1 caused relaxation of phasic activity and agonist-induced tonic contractions in intact colon, suggesting a role of smooth muscle Gs-coupled GLP-1R in mediating relaxation. In SMC, GLP-1 (7-36) amide activated Gas, increased cAMP levels, and stimulated PKA activity. Conclusion. Colonic SMC express GLP-1R, and GLP-1 inhibits both basal and acetylcholine-induced contraction. The GLP1-R is coupled to the heterotrimeric G protein, Gas.
563

The role of genetic variation in glucokinase and glucokinase regulatory protein in diabetes and related traits

Beer, Nicola L. January 2011 (has links)
The rising prevalence of type 2 diabetes (T2D) is a global problem, and suggests that we need better therapeutic strategies against this disease. The glycolytic enzyme glucokinase (GCK) catalyses the phosphorylation of glucose, and is a well-established T2D drug target. Rare GCK mutations cause monogenic beta-cell dysfunction, whilst common genetic variants within GCK are associated with fasting plasma glucose (FPG) levels and T2D risk. Since GCK is expressed in both the pancreas and liver, pharmacological GCK activation provides the promise of a two-pronged attack on hyperglycaemia. In vivo, GCK activity is modulated by the hepatic inhibitor glucokinase regulatory protein (GKRP, gene GCKR). GKRP negatively regulates GCK activity competitively with respect to glucose, and is controlled by fructose 6- and fructose 1-phosphate (F6P and F1P), which compete with each other for binding and enhance or diminish GCK inhibition respectively. GKRP also sequesters GCK in the nucleus and paradoxically stabilises the enzyme. As GCK and its regulatory protein are fundamental to glucose homeostasis, we aimed to investigate the role of genetic variation in both GCK and GCKR to further our understanding of these important T2D drug targets in a system that would be relevant to man. I demonstrated that two novel GCK mutations (T103S and V389L) identified in patients with hyperinsulinaemic hypoglycaemia were kinetically activating and through structural modelling identified a novel regulatory site for GCK activation by small molecular activators. Genome-wide association studies (GWAS) identified GCKR as a regulator of FPG and triglyceride levels, and showed a role for GKRP in T2D risk. Unlike most GWAS hits, this signal included a non-synonymous variant within GCKR (P446L), thus facilitating functional studies. P446L-GKRP was characterised kinetically and at the cellular sequestration-level. This variant showed diminished F6P-mediated modulation, which was proposed to reduce hepatic GCK inhibition, increase glycolytic flux (decreasing FPG), and feed metabolites into liver pathways (elevating triglycerides). As GCKR was not expressed at functional levels within human islets, this phenotype was thought to be driven by the liver. Preliminary analysis at the cellular level was inconclusive, with optimisation required to study human P446L-GKRP in this cellular system. Finally, I showed that mutations within GCKR are not a common cause of “GCK-Like” phenotypes in man, despite the regulatory protein directly modulating GCK activity. These data provide further insight as to the pathogenic consequences of perturbing GCK activity. This must be considered if this enzyme is to be the subject of therapeutic intervention in T2D.
564

Risk factors in type 2 diabetes with emphasis on blood pressure, physical activity and serum vitamin D

E:son Jennersjö, Pär January 2016 (has links)
Background Type 2 diabetes is a common chronic disease with a two-fold increased risk for cardiovascular morbidity and mortality and has an increasing prevalence worldwide. This thesis is based on a study conducted in primary health care in Östergötland and Jönköping, Sweden. The aim of the thesis was to evaluate new risk markers to identify patients with high risk of developing cardiovascular disease in middle-aged men and women with type 2 diabetes. Methods Data from the cohort study CArdiovascular Risk in type 2 DIabetes – a Prospective study in Primary care (CARDIPP) was used. In paper III data were also used from CARDIPP-Revisited where all participants in the CARDIPP study were invited four years after the baseline investigation for a re-investigation. In paper IV data were used from CAREFUL which is a control group of 185 subjects without diabetes. The investigation included a standard medical history including data on diabetes duration and on-going medication. Anthropometric data were recorded and both office and ambulatory blood pressure were measured. The patients filled out a detailed questionnaire and physical activity was measured by using waist-mounted pedometers. Pedometer-determined physical activity was classified in four groups: Group 1: <5000 steps/day (‘sedentary’); Group 2: 5000-7499 steps/day (‘low active’); Group 3: 7500-9999 steps/day (‘somewhat active’); Group 4: and ≥10 000 steps/day (‘active’). Blood samples were drawn for routine analyses and also frozen for later analyses. The investigations at the departments of physiology included echocardiography, measurements of the carotid intima-media thickness, applanation tonometry and measurements of  sagittal abdominal diameter. Results Paper 1: Patients with a non-dipping systolic blood pressure pattern showed higher left ventricular mass index and pulse wave velocity (PWV) compared with patients with ≥10% decline in nocturnal systolic blood pressure. Patients with <10% decline in nocturnal systolic blood pressure had higher BMI and sagittal abdominal diameter, lower GFR and higher albumin:creatinine ratio and also higher levels of NT-proBNP than patients with a dipping pattern of the nocturnal blood pressure. Paper 2: The number of steps/day were inversely significantly associated with BMI, waist circumference and sagittal abdominal diameter, levels of CRP, levels of interleukin-6 and PWV. Paper 3: At the 4-year follow-up the change in PWV (ΔPWV) from baseline was calculated. The group with the lowest steps/day had a significantly higher increase in ΔPWV compared with the group with the highest steps/day. The associations between baseline steps/day and ΔPWV remained after further adjustment in a multivariate linear regression statistically significant (p=0.005). 23% of the variation in the study could be explained by our model. Every 1000 extra steps at baseline reduced the change in ΔPWV by 0.103 m/s between baseline and follow-up. Paper 4: Low vitamin D levels were associated with significantly increased risk for premature mortality in men with type 2 diabetes. High levels of parathyroid hormone were associated with significantly increased risk for premature mortality in women with type 2 diabetes. These relationships were still statistically significant also when two other well-established risk markers for mortality, PWV and carotid intima-media thickness, were added to the analyses. Conclusions Ambulatory blood pressure recording can by addressing the issue of diurnal blood pressure variation, explore early cardiovascular organ damage and microvascular complications that goes beyond effects of standardised office blood pressure measurements. Pedometer-determined physical activity may serve as a surrogate marker for inflammation and subclinical organ damage in patients with type 2 diabetes. There is novel support for the durable vascular protective role of a high level of daily physical activity, which is independent of BMI and systolic blood pressure. The use of pedometers is feasible in clinical practice and provides objective information not only about physical activity but also the future risk for subclinical organ damage in middle-aged people with type 2 diabetes. Our results indicate that low vitamin D levels in men or high parathyroid hormone levels in women give independent prognostic information of an increased risk for total mortality.
565

Efeito do estresse social sobre o comportamento materno do hamster Sírio (Mesocricetus auratus) / Effects of social stress on the maternal behavior of the Syrian hamster (Mesocricetus auratus)

Chelini, Marie Odile Monier 26 February 2010 (has links)
A flexibilidade da socialidade presente em muitas espécies sugere que muitos dos traços comportamentais e fisiológicos presentes em grupos sociais complexos possam existir em estado latente em indivíduos de espécies solitárias. Hierarquia de dominância e assimetria reprodutiva são traços característicos de espécies sociais. O hamster Sírio é um excelente modelo para o estudo do estresse social e dos seus efeitos fisiológicos e comportamentais. Na presente pesquisa foram enfocados os efeitos do alojamento em grupo antes e no início da gestação na fêmea de hamster Sírio. Investigou-se se o estresse social produz algum grau de assimetria reprodutiva nesta espécie solitária e se o sucesso reprodutivo e o comportamento materno das fêmeas variam em função do seu status social. Dois experimentos foram realizados envolvendo respectivamente 34 fêmeas de hamster criadas em grupo do desmame até o início do estudo e 76 fêmeas criadas isoladamente. Em cada experimento, um terço dos animais foram alojados em gaiolas individuais, enquanto pares de fêmeas desconhecidas umas das outras eram formados com os outros dois terços. O comportamento dos pares foi observado ao longo de 10 dias para determinar o status social de cada fêmea. Todas as fêmeas foram acasaladas neste período. Quatro dias após o parto, os filhotes foram contados, sexados e pesados e as ninhadas padronizadas a seis filhotes, três machos e três fêmeas. As mães e suas ninhadas foram observadas diariamente durante sessões de 40min e 13 categorias comportamentais foram registradas. No intuito de esclarecer os mecanismos fisiológicos subjacentes à relação entre estresse social e fertilidade, os níveis dos hormônios reprodutivos e dos glicocorticóides foram monitorados ao longo da gestação por métodos não-invasivos, previamente validados, de quantificação dos seus metabólitos nas fezes. Foi demonstrada, pela primeira vez, a adequação de um enzimaimunoensaio e de um conjunto diagnóstico comercial de radioimunoensaio para a quantificação respectiva dos metabólitos fecais de glicocorticóides em hamsters Sírios dos dois sexos e de testosterona no hamster Sírio macho, mas não da fêmea. As variações das concentrações de metabólitos fecais de progesterona, estrógenos e glicocorticóides, refletiram os perfis séricos descritos na literatura para hamsters gestantes. Os resultados mostram que quando fêmeas de hamster Sírio são alojadas individualmente após o desmame, sua fertilidade não é afetada pelo estresse social. Em contraste, quando as fêmeas são criadas em grupo, o estresse social tanto de isolamento como de subordinação a uma fêmea dominante induz um grau significante de assimetria reprodutiva, traço característico de espécies sociais que criam seus filhotes em comunidade. A manutenção de hamsters cativos adultos em grupos parece despertar traços comportamentais e fisiológicos presentes em grupos sociais complexos e que se encontram em estado latente nesta espécie solitária. A socialidade parece flexível no hamster e modulada pelas condições ecológicas. / The flexibility of sociality found in many species suggests that many of the behavioral and physiological mechanisms responsible for highly developed social interactions are present as latent traits, even in species usually considered as solitary. Social hierarchy and reproductive skew are typical features of social species. Syrian hamsters (Mesocricetus auratus) are an ideal model for the investigation of social stress and its physiological, neuroendocrine, and behavioral effects. The present research focused on the effects of group-housing prior to mating and on the first days of gestation of the female hamster. We investigated if social stress produces some degree of reproductive skew in this solitary species, and if female reproductive success varies as a function of social rank. Two experiments were carried out. The first one involved 34 females group-raised from weaning until the beginning of the trial and the second one 76 singly raised females. In each case one third of the animals were singly housed. Pairs of unrelative females were formed with the remaining animals. Pair behavior was observed through 10 days for assessment of the social rank of each female. All females were mated during this period. On day 4 post-partum, pups were counted, sexed, and weighed and litters were culled to six, three males and three females. Litters and dams were observed daily through 40-min sessions and 13 behavioral categories recorded. In order to assess the physiological relationship between social stress and fertility, we monitored reproductive hormones and glucocorticoids of solitary and pair-housed females during pregnancy by utilizing recently established non-invasive methods for measuring the respective hormone metabolites in the feces. The suitability of an enzyme immunoassay and of a commercial radioimmunoassay for respective quantification of fecal glucocorticoid metabolites of hamsters of both sexes and fecal testosterone metabolites in the male but not in the female was proven for the first time. The patterns of fecal progesterone, estrogen, and glucocorticoid metabolites were similar to blood profiles reported in the literature for pregnant hamsters. Our results showed that when female hamsters are singly housed from weaning, social stress did not affect their fertility. However, when females are group-raised, both isolation and subordination stress induced a significant reproductive skew, which is a characteristic feature of cooperative breeders. It seems that group-keeping of adult hamsters evokes social physiological and behavioral mechanisms present as latent traits in this solitary species. As in other rodents, sociability seems flexible in the Syrian hamster and our findings support the idea that social interactions may be a function of ecological conditions.
566

Transgenic expression of molt-inhibiting hormone from white shrimp (penaeus vannamei) in tobacco.

January 2001 (has links)
by Fong Man Kim. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 127-137). / Abstracts in English and Chinese. / Thesis committee --- p.i / Acknowledgements --- p.ii / Abstract --- p.iii / List of figures --- p.viii / List of tables --- p.xi / Abbreviations --- p.xii / Table of contents --- p.xiv / Chapter CHAPTER 1 --- GENERAL INTRODUCTION --- p.1 / Chapter CHAPTER 2 --- LITERATURE REVIEW --- p.3 / Chapter 2.1 --- MIH from Penaeus vannamei --- p.3 / Chapter 2.1.1 --- General Introduction to P. vannamei --- p.3 / Chapter 2.1.1.1 --- Morphology --- p.3 / Chapter 2.1.1.2 --- Geographical distribution --- p.5 / Chapter 2.1.1.3 --- Economic value --- p.5 / Chapter 2.1.2 --- Physiology of Molting in Crustacean --- p.7 / Chapter 2.1.2.1 --- The molt cycle --- p.7 / Chapter 2.1.2.2 --- Physiological effects of ecdysone --- p.8 / Chapter 2.1.2.3 --- Regulation of the secretion of ecdysone --- p.9 / Chapter 2.1.2.4 --- Physiological effects of Molt-inhibiting hormone --- p.10 / Chapter 2.1.3 --- Cloning of MIH cDNA from P. vannamei --- p.14 / Chapter 2.1.3.1 --- Molecular identity of MIH --- p.14 / Chapter 2.1.3.2 --- Cloning of MIH cDNA --- p.15 / Chapter 2.1.3.3 --- Comparison of the cloned MIH-like cDNA with the CHH/MIH/VIH peptide family --- p.16 / Chapter 2.2 --- Plants as Bioreactors --- p.20 / Chapter 2.2.1 --- Principles & Techniques --- p.20 / Chapter 2.2.2 --- Advantages of plant bioreactors --- p.21 / Chapter 2.2.3 --- Tobacco expression system --- p.22 / Chapter 2.2.3.1 --- Tobacco as model plants --- p.22 / Chapter 2.2.3.2 --- Transformation methods --- p.23 / Chapter 2.2.4 --- Phaseolin --- p.26 / Chapter CHAPTER 3 --- EXPRESSION OF MIH IN TRANSGENIC TOBACCO --- p.28 / Chapter 3.1 --- Introduction --- p.28 / Chapter 3.2 --- Materials & Methods --- p.29 / Chapter 3.2.1 --- Chemicals --- p.29 / Chapter 3.2.2 --- Plant materials --- p.29 / Chapter 3.2.3 --- Bacterial strains and plasmid vectors --- p.30 / Chapter 3.2.4 --- Construction of chimeric genes - --- p.30 / Chapter 3.2.4.1 --- PCR amplification of MIH --- p.30 / Chapter 3.2.4.2 --- Cloning of PCR-amplified MIH into vector pET --- p.31 / Chapter 3.2.4.3 --- Cloning of MIH into vector pBK/Phas-sp and pTZ/Phas --- p.31 / Chapter 3.2.4.4 --- Cloning of MIH into binary vector pBI121 --- p.32 / Chapter 3.2.5 --- Transformation of Agrobacterium with pBI121/Phas-sp-MIH and pBI121 /Phas-MIH by electroporation --- p.39 / Chapter 3.2.6 --- Transformation of tobacco --- p.40 / Chapter 3.2.7 --- Selection of transgenic plants --- p.41 / Chapter 3.2.8 --- GUS assay --- p.42 / Chapter 3.2.9 --- Extraction of leaf genomic DNA --- p.43 / Chapter 3.2.10 --- Extraction of total RNA from developing seeds --- p.44 / Chapter 3.2.11 --- Synthesis of DIG-labeled DNA and RNA probes --- p.45 / Chapter 3.2.12 --- Southern blot analysis of genomic DNA --- p.47 / Chapter 3.2.13 --- Reverse transcriptase - polymerase chain reaction (RT-PCR) --- p.47 / Chapter 3.2.14 --- Northern blot analysis of total RNA --- p.48 / Chapter 3.2.15 --- Protein extraction and tricine-SDS-PAGE --- p.49 / Chapter 3.2.16 --- Purification of 6xHis-tag proteins --- p.50 / Chapter 3.2.17 --- Western blot analysis --- p.50 / Chapter 3.2.18 --- In vitro transcription & translation --- p.52 / Chapter 3.2.18.1 --- Construction of transcription vector containing the chimeric MIH gene --- p.52 / Chapter 3.2.18.2 --- In vitro transcription --- p.56 / Chapter 3.2.18.3 --- In vitro translation --- p.56 / Chapter 3.2.19 --- Particle bombardment --- p.57 / Chapter 3.2.19.1 --- Construction of MIH-GUSN fusion chimeric genes --- p.57 / Chapter 3.2.19.2 --- Conditions of particle bombardment --- p.63 / Chapter 3.2.20 --- Codon modification of MIH gene --- p.63 / Chapter 3.3 --- Results --- p.73 / Chapter 3.3.1 --- Construction of chimeric MIH genes --- p.73 / Chapter 3.3.2 --- "Tobacco transformation, selection and regeneration" --- p.73 / Chapter 3.3.3 --- Detection of GUS activity --- p.74 / Chapter 3.3.4 --- Southern blot analysis --- p.79 / Chapter 3.3.5 --- Detection of MIH transcript in transgenic tobacco --- p.83 / Chapter 3.3.5.1 --- RT-PCR --- p.83 / Chapter 3.3.5.2 --- Northern blot analysis --- p.86 / Chapter 3.3.6 --- Detection of MIH protein by Tricine-SDS-PAGE --- p.86 / Chapter 3.3.7 --- Detection of MIH protein by western blot analysis --- p.88 / Chapter 3.3.7.1 --- Western blot analysis using Anti-MIH antibody --- p.88 / Chapter 3.3.7.2 --- Western blot analysis using Anti-His antibody --- p.90 / Chapter 3.3.7.3 --- Western blot analysis using Anti-MIHA & Anti-MIHB antibodies --- p.90 / Chapter 3.3.8 --- Purification of 6xHis-tag proteins by Ni-NTA column --- p.94 / Chapter 3.3.8.1 --- Western blot analysis of proteins purified by Ni-NTA column --- p.97 / Chapter 3.3.9 --- In vitro transcription and translation --- p.100 / Chapter 3.3.9.1 --- In vitro transcription --- p.100 / Chapter 3.3.9.2 --- In vitro translation --- p.100 / Chapter 3.3.10 --- Particle bombardments --- p.103 / Chapter 3.3.10.1 --- Transient expression of MIH in soybean & tobacco leaves --- p.103 / Chapter CHAPTER 4 --- DISCUSSION --- p.107 / Chapter 4.1 --- Transient expression of MIH genes --- p.109 / Chapter 4.1.1 --- In vitro transcription and translation --- p.109 / Chapter 4.1.2 --- Particle bombardments --- p.220 / Chapter 4.2 --- Post-transcriptional gene silencing (PTGS) --- p.114 / Chapter 4.2.1 --- Post-transcriptional cis-inactivation --- p.114 / Chapter 4.2.2 --- Post-transcriptional trans-inactivation --- p.116 / Chapter 4.2.3 --- MIH gene and PTGS --- p.118 / Chapter 4.3 --- Codon usage --- p.119 / Chapter 4.3.1 --- Codon usage of MIH in plants --- p.120 / Chapter 4.3.2 --- Codon modification of MIH and further study on MIH expression in plants --- p.122 / Chapter 4.4 --- Post-translational protein degradation --- p.123 / Chapter 4.4.1 --- Construction of LRP-MIH fusion proteins --- p.123 / CONCLUSION --- p.125 / REFERENCES --- p.127
567

Immunomodulation of thymic function and T cell differentiation by oestrogens in the European sea bass, Dicentrarchus labrax : an evolutionary and ecotoxicological perspective / Immunomodulation de la fonction thymique et de la différentiation des lymphocytes T chez le bar européen, Dicentrarchus labrax : une perspective évolutive et écotoxicologique

Paiola, Matthieu 19 February 2018 (has links)
Chez les vertébrés gnathostomes, le système immunitaire repose en grande partie sur les lymphocytes T qui se développent dans un organe conservé évolutivement : le thymus. Chez les mammifères, cet organe constitue une cible privilégiée pour les œstrogènes. La question soulevée ici est donc de savoir si c’est également le cas chez les poissons téléostéens. Dans ce but, la distribution des différents sous-types de récepteurs aux œstrogènes a d’abord été étudiée dans le contexte d’une description de l’anatomie fonctionnelle du microenvironnement thymique. Par la suite, l’expression de gènes relatifs à la fonction thymique et aux différents sous-types de lymphocyte T a été analysée dans le thymus, le rein-antérieur et la rate de bars exposés au 17ß-œstradiol. De plus, la capacité de flambée oxydative a été évaluée sur des leucocytes du rein-antérieur et de rate à la suite d’expositions in vivo et in vitro. Finalement, la variation du nombre de thymocytes a été examinée sur des bars capturés durant trois ans. La thèse fournit de nouvelles connaissances concernant l’évolution des fonctions immunomodulatrices des œstrogènes sur la différenciation des cellules T. En effet, en plus d’une organisation morpho-fonctionnelle fortement conservée, la distribution des sous-types de récepteurs aux œstrogènes ainsi que les effets œstrogéniques apparaissent conservés au cours de l’évolution. Nos résultats suggèrent que, chez le bar comme chez les mammifères, les œstrogènes (1) stimulent une voie alternative de maturation des lymphocytes T ayant des propriétés similaires aux cellules immunitaires innées, (2) augmentent la tolérance immunitaire et (3) régulent la plasticité du thymus. / Jawed vertebrates have developed an efficient adaptive immune system partly based on T lymphocytes. They develop in an evolutionarily conserved organ, the thymus. In mammals, endogenous oestrogens are well known to regulate thymus function and plasticity. The question is, therefore, whether this is also the case in lower vertebrates, such as teleosts. To achieve these aims, firstly the distribution of oestrogen receptor subtypes was investigated on the background of a detailed description of the functional anatomy of the thymic microenvironment. Secondly, thymic function- and T cell-related gene expression was analysed in the thymus, the head-kidney and the spleen of sea bass exposed to 17ß-oestradiol. Moreover, the oxidative burst capacity in the two latter organs was evaluated in vivo and in vitro in leucocytes of the head-kidney and spleen following exposure to oestrogen. Eventually, age- and size-dependent variations in thymocyte number were examined in sea bass caught at various time points over three years. The thesis provides new insights into the evolution of the immunomodulatory function of oestrogen with respect to the thymic and peripheral T cell differentiation in vertebrates. As a matter of fact, in addition to a highly conserved morpho-functional organisation, the distribution of oestrogen receptor subtypes as well as the oestrogenic effects appear to be evolutionarily conserved. Our results suggest that in sea bass, similar to mammals, oestrogen (1) stimulates a thymic alternative pathway of T cell maturation with innate-like properties, (2) enhances immune tolerance by promoting Treg differentiation, and (3) actively regulate thymic plasticity.
568

Prevalência de Síndrome Metabólica em Diabetes Mellitus tipo 2 e associação com Doença Coronariana.

Miyamoto, Janine Hatsumi 25 January 2012 (has links)
Made available in DSpace on 2016-01-26T12:51:31Z (GMT). No. of bitstreams: 1 janinehatsumimiyamoto_dissert.pdf: 287223 bytes, checksum: 94be79897234bdddd89d8d839f550e34 (MD5) Previous issue date: 2012-01-25 / Diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia resulting from insulin secretion defects, in its peripheral action, or both. Clinical manifestations of diabetes are broad and can range from asymptomatic glucose intolerance to acute complications as diabetic ketoacidosis or complications of slow evolution, such as neurological and vascular changes. Vascular changes affect virtually every body's blood vessels, large and small ones, constituting macro-and microangiopathy, respectively. The main clinical expressions of microangiopathy are diabetic nephropathy and retinopathy. The macroangiopathy is represented by early atherosclerosis, more severe and more frequent than that observed in non-diabetic population. The non-establishment or definition of a glycemic threshold in diabetic patients and the persistence of this relationship in non-diabetics suggest that glucose is a continuous variable risk, as well as other cardiovascular risk factors. The diabetic dyslipidemia is characterized by an increase in LDL small and dense particles, the reduction in HDL-cholesterol and high triglycerides levels. Diabetes or pre-diabetes, low HDL-cholesterol, high triglycerides and arterial hypertension are risk factors, when linked to central obesity, form the metabolic syndrome and 1.5-fold increase in overall mortality and 2.5 in cardiovascular mortality. Given the above, the purpose of the study was to assess the prevalence of metabolic syndrome according to the definition of the National Cholesterol Education Program Adult Treatment Panel III in patients with type 2 diabetes mellitus, its association and components with coronary disease. A total of 610 patients with type 2 diabetes mellitus were retrospectively analyzed, concerning age, gender, clinical and metabolic characteristics. The prevalence of metabolic syndrome was 78.4%. The comparative analysis between the groups with and without metabolic syndrome was significantly associated with coronary artery disease (p=0.032). By means of logistic regression, waist circumference (p=0.79) and fasting glucose (p=0.13) were not significant. The arterial hypertension (p=0.01) and dyslipidemia (p=0.005) showed significant association with coronary artery disease. Therefore, we can conclude that the metabolic syndrome is highly prevalent in patients with type 2 diabetes mellitus; it has shown an association with coronary heart disease and among its components, arterial hypertension and dyslipidemia indicate a significant association. / Diabetes Mellitus constitui um grupo de doenças metabólicas caracterizado por hiperglicemia resultante de defeitos na secreção de insulina, na sua ação periférica ou em ambas. As manifestações clínicas do diabetes são amplas e podem compreender desde intolerância assintomática à glicose até complicações agudas como a cetoacidose diabética ou complicações de evolução lenta, tais como alterações vasculares e neurológicas. As alterações vasculares atingem praticamente todos os vasos do organismo, pequenos e grandes, constituindo a micro e a macroangiopatia, respectivamente. As principais expressões clínicas da microangiopatia são a retinopatia e a nefropatia diabética. A macroangiopatia é representada pela aterosclerose mais precoce, mais grave e mais frequente que a observada na população não diabética. O não estabelecimento ou definição de um limiar glicêmico em diabéticos e a persistência desta relação em não-diabéticos sugerem que a glicemia é uma variável contínua de risco, da mesma forma que outros fatores de risco cardiovascular. A dislipidemia diabética caracteriza-se pelo aumento de partículas de LDL pequenas e densas, pela redução do HDL colesterol e valores elevados de triglicérides. Diabetes ou pré-diabetes, baixo valor de HDL colesterol, triglicérides elevado e hipertensão são fatores de risco que, ligados à obesidade central, formam a síndrome metabólica e aumentam em 1,5 vezes a mortalidade geral e em 2,5 vezes, a cardiovascular. Diante do exposto, o propósito do estudo foi avaliar a prevalência de síndrome metabólica de acordo com a definição do National Cholesterol Education Program Adult Treatment Panel III em pacientes com diabetes mellitus tipo 2 e a sua associação e a dos seus componentes com a doença coronariana. Um total de 610 pacientes com diabetes mellitus tipo 2 foram analisados, retrospectivamente, quanto à idade, sexo e características clínicas e metabólicas. A prevalência de síndrome metabólica foi de 78,4%. A Análise comparativa entre os grupos com e sem síndrome metabólica mostrou associação significativa com a doença coronariana (p=0,032). Por meio de regressão logística, a circunferência abdominal (p=0,79) e a glicemia de jejum (p=0,13) não foram significativas. A hipertensão arterial (p=0,01) e a dislipidemia (p=0,005) evidenciaram associação significativa com a doença coronariana. Portanto, podemos concluir que a síndrome metabólica tem alta prevalência em pacientes com diabetes mellitus tipo 2; mostrou associação com doença coronariana e entre os seus componentes, a hipertensão arterial e a dislipidemia denotaram associação significativa.
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Efeito do estresse social sobre o comportamento materno do hamster Sírio (Mesocricetus auratus) / Effects of social stress on the maternal behavior of the Syrian hamster (Mesocricetus auratus)

Marie Odile Monier Chelini 26 February 2010 (has links)
A flexibilidade da socialidade presente em muitas espécies sugere que muitos dos traços comportamentais e fisiológicos presentes em grupos sociais complexos possam existir em estado latente em indivíduos de espécies solitárias. Hierarquia de dominância e assimetria reprodutiva são traços característicos de espécies sociais. O hamster Sírio é um excelente modelo para o estudo do estresse social e dos seus efeitos fisiológicos e comportamentais. Na presente pesquisa foram enfocados os efeitos do alojamento em grupo antes e no início da gestação na fêmea de hamster Sírio. Investigou-se se o estresse social produz algum grau de assimetria reprodutiva nesta espécie solitária e se o sucesso reprodutivo e o comportamento materno das fêmeas variam em função do seu status social. Dois experimentos foram realizados envolvendo respectivamente 34 fêmeas de hamster criadas em grupo do desmame até o início do estudo e 76 fêmeas criadas isoladamente. Em cada experimento, um terço dos animais foram alojados em gaiolas individuais, enquanto pares de fêmeas desconhecidas umas das outras eram formados com os outros dois terços. O comportamento dos pares foi observado ao longo de 10 dias para determinar o status social de cada fêmea. Todas as fêmeas foram acasaladas neste período. Quatro dias após o parto, os filhotes foram contados, sexados e pesados e as ninhadas padronizadas a seis filhotes, três machos e três fêmeas. As mães e suas ninhadas foram observadas diariamente durante sessões de 40min e 13 categorias comportamentais foram registradas. No intuito de esclarecer os mecanismos fisiológicos subjacentes à relação entre estresse social e fertilidade, os níveis dos hormônios reprodutivos e dos glicocorticóides foram monitorados ao longo da gestação por métodos não-invasivos, previamente validados, de quantificação dos seus metabólitos nas fezes. Foi demonstrada, pela primeira vez, a adequação de um enzimaimunoensaio e de um conjunto diagnóstico comercial de radioimunoensaio para a quantificação respectiva dos metabólitos fecais de glicocorticóides em hamsters Sírios dos dois sexos e de testosterona no hamster Sírio macho, mas não da fêmea. As variações das concentrações de metabólitos fecais de progesterona, estrógenos e glicocorticóides, refletiram os perfis séricos descritos na literatura para hamsters gestantes. Os resultados mostram que quando fêmeas de hamster Sírio são alojadas individualmente após o desmame, sua fertilidade não é afetada pelo estresse social. Em contraste, quando as fêmeas são criadas em grupo, o estresse social tanto de isolamento como de subordinação a uma fêmea dominante induz um grau significante de assimetria reprodutiva, traço característico de espécies sociais que criam seus filhotes em comunidade. A manutenção de hamsters cativos adultos em grupos parece despertar traços comportamentais e fisiológicos presentes em grupos sociais complexos e que se encontram em estado latente nesta espécie solitária. A socialidade parece flexível no hamster e modulada pelas condições ecológicas. / The flexibility of sociality found in many species suggests that many of the behavioral and physiological mechanisms responsible for highly developed social interactions are present as latent traits, even in species usually considered as solitary. Social hierarchy and reproductive skew are typical features of social species. Syrian hamsters (Mesocricetus auratus) are an ideal model for the investigation of social stress and its physiological, neuroendocrine, and behavioral effects. The present research focused on the effects of group-housing prior to mating and on the first days of gestation of the female hamster. We investigated if social stress produces some degree of reproductive skew in this solitary species, and if female reproductive success varies as a function of social rank. Two experiments were carried out. The first one involved 34 females group-raised from weaning until the beginning of the trial and the second one 76 singly raised females. In each case one third of the animals were singly housed. Pairs of unrelative females were formed with the remaining animals. Pair behavior was observed through 10 days for assessment of the social rank of each female. All females were mated during this period. On day 4 post-partum, pups were counted, sexed, and weighed and litters were culled to six, three males and three females. Litters and dams were observed daily through 40-min sessions and 13 behavioral categories recorded. In order to assess the physiological relationship between social stress and fertility, we monitored reproductive hormones and glucocorticoids of solitary and pair-housed females during pregnancy by utilizing recently established non-invasive methods for measuring the respective hormone metabolites in the feces. The suitability of an enzyme immunoassay and of a commercial radioimmunoassay for respective quantification of fecal glucocorticoid metabolites of hamsters of both sexes and fecal testosterone metabolites in the male but not in the female was proven for the first time. The patterns of fecal progesterone, estrogen, and glucocorticoid metabolites were similar to blood profiles reported in the literature for pregnant hamsters. Our results showed that when female hamsters are singly housed from weaning, social stress did not affect their fertility. However, when females are group-raised, both isolation and subordination stress induced a significant reproductive skew, which is a characteristic feature of cooperative breeders. It seems that group-keeping of adult hamsters evokes social physiological and behavioral mechanisms present as latent traits in this solitary species. As in other rodents, sociability seems flexible in the Syrian hamster and our findings support the idea that social interactions may be a function of ecological conditions.
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Prenatal Exposures to Perfluoroalkyl Acids and Serum Lipids at Ages 7 and 15 in Females

Maisonet, Mildred, Näyhä, Simo, Lawlor, Debbie A., Marcus, Michele 01 September 2015 (has links)
Background In some cross-sectional epidemiologic studies the shape of the association between serum concentrations of perfluoroalkyl acids (PFAAs) and lipids suggests departures from linearity. Objectives We used statistical approaches allowing for non-linearity to determine associations of prenatal exposures of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) with lipid concentrations. Methods PFAAs were measured in serum from pregnant women collected in 1991–1992 at enrollment in the Avon Longitudinal Study of Parents and Children and lipids in serum from their daughters at ages 7 (n = 111) and 15 (n = 88). The associations of PFAAs with lipids were first explored by cubic splines, followed by piecewise linear regressions by tertiles to obtain regression coefficients (β) and their 95% confidence limits (95% CL) (in mg/dL per 1 ng/mL). Results At age 7, total cholesterol was positively associated with prenatal PFOA concentrations in the lower tertile (β = 15.01; 95% CL = 2.34, 27.69) but not with PFOA concentrations in the middle (β = − 3.63; 95% CL = − 17.43, 10.16) and upper (β = − 1.58; 95% CL = − 4.58, 1.42) tertiles. At age 15, a similar pattern was noted as well. Positive associations between LDL-C and prenatal PFOA concentration in the lower tertile were observed in daughters at ages 7 (β = 14.91; 95% CL = 3.53, 28.12) and 15 (β = 13.93; 95% CL = 0.60, 27.26). LDL-C was not associated with PFOA concentrations in the middle or upper tertile at any age. Neither HDL-C nor triglycerides was associated with prenatal PFOA exposure. Non-linear patterns of association of total cholesterol and LDL-C with prenatal PFOS were less consistently noted. Conclusion Exposure to low levels of PFOA during prenatal development may alter lipid metabolism later in life. Given the small sample size further replication of the association in large independent cohorts is important.

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