Thesis (Ph. D.)--Lehigh University, 2000. / Includes bibliographical references and vita.

Resumo: Avaliar o perfil da densidade mineral óssea (DMO) e os fatores de risco associados à osteoporose na pós-menopausa. Realizou-se estudo clínico-transversal com 431 mulheres. Idade entre 40-75 anos, atendidas ambulatorialmente em Hospital Universitário. Incluíram-se mulheres com: amenorréia>12 meses e idade ≥45 anos ou, ooforectomia ≥40 anos, com valores de DMO (coluna lombar e colo de fêmur) pelo DEXA dos últimos 12 meses. Fatores de risco avaliados: idade, idade e tempo de menopausa, tabagismo, atividade física (30min/5x/sem), artrite reumatóide (AR), uso de corticoterapia e de terapia hormonal (TH), fratura prévia, fratura materna de quadril e índice de massa corpórea (IMC=peso/altura2). Valores séricos de cálcio, fosfatase alcalina (FA) e calciúria-24h foram analisados. Empregou-se teste do Qui-quadrado (variáveis categóricas) e método de regressão logística no risco (odds ratio-OR) para osteoporose. A média de idade foi 54,1 ± 6,9 anos, tempo de menopausa 7,5 ± 5,8 anos, IMC 28,2 ± 5,3kg/m2. Encontrou-se: usuárias de TH 35,9%, exercício regular 27,3%, tabagistas 23,8%, menopausa <40anos 18,1%, fratura prévia 11,8%, fratura materna de quadril 10,7%, corticoterapia 4,8%, AR 4,0%. Pelos critérios da OMS, 106 (24,6%) mulheres apresentavam osteoporose (T-escore≤-2,5DP), 188 (43,6%) osteopenia (-1,0/-2,4DP) e 137 (31,8%) eram normais (≥-1,0DP). Detectou-se osteoporose em 12% das mulheres com idade entre 40-49anos, 21,8% 50-59 anos e 45,7% >60 anos (p<0,001). Osteoporose ocorreu em 11,8% com tempo de menopausa <5anos, 29,4% de 6-10anos, e 41% >10anos (p<0,001). Naquelas com menopausa precoce, 80% apresentaram osteopenia/osteoporose (p=0,032) e com IMC<20kg/m2, 50% osteoporóticas (p<0,001). Nenhuma associação foi observada entre DMO e valores de cálcio (p=0,174), FA (p=0,901) e calciúria (p=0,759). O risco de detectar osteoporose aumentou com idade... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: To evaluate bone mineral density (BMD) profiles and their risk factors associated with postmenopausal osteoporosis. A cross-sectional clinical study was performed on 431 women aged 40-75 years and cared for at the outpatient clinic of a University Hospital. Women showing the following characteristics were included: amenorrhea >12 months and age ≥ 45 years or, ooforectomy ≥ 40 years with BMD values (lumbar spine and femur neck) by DXA of the last 12 months. Risk factors evaluated: age, age and time of menopause, smoking, physical activity (30min/5x/week), rheumatoid arthritis (RA), use of corticotherapy and hormone therapy (HT), previous fracture, maternal hip fracture and body mass index (BMI=weight/height2). Serum values of calcium, alkaline phosphatase (AP) and 24-h urinary calcium were analyzed. The Chi-square test was used for categorical variables, and the logistic regression method (odds ratio-OR) was utilized for osteoporosis risk. Mean age was 54.1±6.9 years, menopausal period 7.5±5.8 years, BMI 28.2±5.3 kg/m2. The following were found: HT users 35.9%; regular exercise 27.3%; smokers 23.8%; menopause < 40 years 18.1%; low calcium intake (<400mg/day) 55.3%; previous fracture 11.8%; maternal fracture 10.7%, corticotherapy 4.8%, RA 4.0%. According to WHO criteria, 106 (24.6%) women showed osteoporosis (T- score ≤ -2.5 DP), 188 (43.6%) osteopenia (-1.0/-2.4 DP), and 137 (31.8%) were normal (≥ -1.0 DP). Osteoporosis was detected in 12% of the women aged 40-49 years, 21.8% 50-59 years and 45.7% > 60 years (p<0.001). Osteoporosis occurred to 11.8% with a menopause period < 5 years, 29.4% from 6 to 10 years, and 41% > 10 years (p<0.001). Of the women with early menopause, 80% showed osteopenia/osteoporosis (p=0.032), and of those with BMI < 20kg/m2, 50% were osteoporotic (p<0.001). No association was observed between BMD and calcium values (p=0.174), AP (p=0.901)... (Complete abstract click electronic access below) / Orientador: Jorge Nahás Neto / Coorientador: Eliana Aguiar Petri Nahás / Banca: Rogério Bonassi Machado / Banca: Adriana O. Pedro / Mestre

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A sensitive and reproducible double antibody radioimmunoassay technique, requiring 50ul of unknown serum or plasma per assay tube, is described for use with 125I and rabbit anti-rat LH serum. The assay system was applied to the study of LH secretion in rats under both normal and experimentally manipulated conditions. Particular attention was focussed upon comparison of circulating LH levels in conscious, unstressed animals with those in anaesthetized animals, with or without surgical stress. Thereafter, the effects of acoustic stimulation and of exogenous LRH administration were studied in conscious and anaesthetized animals. Urethane anaesthesia exerted a profound effect upon the LR-secretory response to exogenous LRH in male rats. Available evidence suggests that the blood sampling method, surgical stress and anaesthesia are each capable of significantly influencing LH secretion, thereby emphasizing the value of studies using conscious, unstressed animals. While a direct effect of urethane on the pituitary gland cannot be excluded, attention is drawn to the possible mediation of a urethane-sensitive inhibitory influence in the mechanism controlling LH secretion in the rat.

PhD (Chemical Pathology),Faculty of Health Sciences, University of the Witwatersrand, 2009 / Introduction: The data published by the Medical Research Council of South Africa demonstrated that cardiovascular disease and diabetes mellitus are the second and tenth leading causes of death in South Africa, respectively (Bradshaw et al.,2003). The prevalence of obesity is higher in the African than Indian population (Puoane et al., 2002), whereas cardiovascular diseases (CVD) and diabetes are more common in the latter population (Omar et al., 1994, Joffe et al., 1994). Diabetes and hypertension has been related with abdominal obesity in a number of studies conducted in the African and mixed-ancestry communities of the Western Cape (Steyn et al., 1996, Levitt et al., 1993). The reason for the high prevalence of obesity in the African population is not known however it is known that the aetiology of obesity involves both environmental and genetic factors (Grundy, 2004). Objective: The main aim of this project was to ascertain the role of metabolic, hormonal, anthropometric and environmental factors in the pathogenesis of obesity-related disorders in two South African ethnic groups namely Indian and African women. These populations were chosen because of the wide differences in risk factors for the development of CVD and diabetes reported in these groups. Subjects and methods: Plasma and serum samples were taken during a 5-hour OGTT from 20 lean, 20 obese, 20 obese type 2 diabetic patients, and 10 overweight women of African and Indian origin, i.e. 140 subjects in total. All participants were recruited from an urban population of women residing in the Greater Johannesburg area. Serum insulin, C-peptide, proinsulin and adipokines were measured using ELISA kits. Fasting plasma glucose, serum cholesterol, HDL-cholesterol and triglycerides levels were measured on the ROCHE MODULAR System. Insulin resistance was calculated using HOMA. Visceral and subcutaneous fat areas were measured using a 5-level CT-scan. Nutrient intake was assessed using a validated quantified food frequency questionnaire. Socio-economic status was estimated from the level of education and the number of selected household amenities. The data collected from the project was analysed by using SAS System for Windows Release 8.02 SAS Institute Inc., Cary, NC, USA 1999-2001. V Results: Results from the study presented in the table below indicate that Indian females were more insulin resistant and had a worse atherogenic lipid profile than African females (statistically higher LDL and triglycerides levels). The greater visceral fat mass in the Indian subjects appears to be associated with triglycerides and correlated with insulin resistance (r=0.554, p<0.05). This effect was not observed in Africans. African females had a higher proportion of their energy intake as carbohydrates than Indians (49.3% and. 45.2%, respectively, p<0.05), whereas Indians had a higher proportion of their total energy intake as fat than Africans (34.0% and 29.9%, respectively, p<0.05). The level of educational attainment and possession of household amenities was lower in the African than Indian group, but this did not significantly influence any of the anthropometric variables. Conclusions: Visceral fat accumulation was greater in diabetic and lean Indian subjects than in diabetic and lean African groups, which may explain their higher risk for obesity-related disorders at lower BMI. Significantly higher HOMA levels in obese Indians and significantly lower proinsulin/insulin ratio in lean and obese Indian women compared to lean and obese African women suggests that lean and obese Indians have better beta-cell proinsulinprocessing efficiency than Africans, probably due to the higher secretory load imposed on beta cells by the higher level of insulin resistance in the Indian subjects. Triglycerides, one of the major components in the diagnostic criteria of metabolic syndrome, were significantly different in the obese group (higher in Indians) and this may lead to the higher prevalence of CVD in the Indian population. Interethnic differences for leptin levels were observed in the lean group of women with higher levels in the Indian subjects. When all non-diabetic subjects were combined serum leptin levels were significantly higher in Indian than African subjects. This is an intriguing result, since obesity is more common in the African than Indian populations of South Africa. Caloric intake was higher in lean African than Indian females. However, the hypothesis that lower leptin levels in lean African females may lead to higher dietary intake and thus an increased prevalence of obesity in this group must be evaluated in a longitudinal study of leptin levels and weight gain. The impact of lower socio-economic status in African than Indian population is not clear; however data from the literature does demonstrate a negative correlation of obesity prevalence with education and income

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Call number: LD2668 .T4 1984 S585 / Master of Science

published_or_final_version / Zoology / Master / Master of Philosophy

published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy