There has been a great deal of focus on young people and how they obtain information about reproductive health matters in the era of HIV/AIDS. However, there has very limited research on role of traditional initiation schools in the era of HIVIAIDS. In some parts of South Africa, young men and women continue to attend traditional initiation schools. The primary aim of these schools is to disseminate information about sexuality and other reproductive health matters in order to ensure that young people are well prepared for their future social growth, societal responsibilities and conjugal matters. Interviews were conducted with young people who had attended traditional initiation schools. The study was conducted in three villages in the Limpopo Province in South Africa where traditional initiations are widely practices. The study examines the impact of traditional initiation schools on adolescent's sexuality and reproductive health behaviour. The findings of the study show that traditional initiation schools have an important role to play in imparting information about sexuality and reproductive health. Traditional initiation schools prepare young people for the transition to adulthood. It is believed that these schools produce men who are independent, brave and courageous and women who are good mothers, wives and daughter-in-Iaws. However, some young men and women feel that they are more likely to engage in sexual activities soon after attending traditional initiation schools. This is because there is massive use of sexually explicit language during the process of initiation. Some young people feel that traditional initiation schools have contributed to the increase in sexual activity and as a result, negative reproductive health outcomes. However, the main conclusion is that traditional initiation schools have an important role to play to shaping the sexual and reproductive health behaviour of Venda young men and women. / Thesis (M.A.)-University of KwaZulu-Natal, Durban, 2005.

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Type-2 diabetes is one of the most prevalent non-communicable diseases globally. The prevalence has increased rapidly in both developed and developing countries. Type-2 diabetes has become epidemic in China in the past three decades. With a relatively low obesity prevalence compared to western countries, such as the United States, the question has arisen as to why people in China are so susceptible to diabetes, but few studies have answered this question definitively. Asians have lower muscle mass than Caucasians which could be one possible explanation. This study aims to test the hypothesis that pubertal muscle mass acquisition, under the influence of testosterone, may be a risk factor for diabetes. This study recruited from the population-representative Chinese “Children of 1997” birth cohort with 8327 participants (88% of all infants born in April and May 1997) in Hong Kong. Participants were aged 15 years at the time of this study. The main objective was to examine the association of pubertal muscle mass with diabetes risk factors, and to examine determinants of pubertal muscle mass in this non-western setting. In June to August 2012, 502 participants from “Children of 1997” were recruited to complete a health assessment follow up at the Active Health Clinic in University of Hong Kong, including a questionnaire, blood tests and a physical examination. Multivariable linear regression was used to assess the associations of: (1) testosterone and pubertal muscle mass with diabetes risk factors, including fasting glucose, fasting insulin and homeostasis model assessment -insulin resistance (HOMA-IR), and any mediation of the association of testosterone with diabetes risk factors by pubertal muscle mass, and (2) environmental influences, including intergenerational influences, proxied by mother’s place of birth, and current life style influences (meat consumption and physical activity), with pubertal muscle mass. Higher pubertal testosterone was associated with lower fasting glucose (-0.008, 95% confidence interval (CI) -0.015 to -0.002), fasting insulin (-0.44, 95% CI -0.57 to -0.31) and HOMA-IR (-0.090, 95% CI -0.12 to -0.063) after adjusting for potential confounders, i.e, sex, birth weight, highest parental education, mother’s place of birth and physical activity. The association was partially mediated by skeletal muscle mass and body fat percentage. Skeletal muscle mass was negatively associated with fasting glucose (-0.017, 95% CI -0.025 to -0.009), insulin (-0.876, 95% CI -1.033 to -0.719), and HOMA-IR (-0.180, 95% CI -0.214 to -0.147) after adjusted for potential confounders. High meat consumption (0.176, 95% CI 0.000 to 0.351) and physical activity (0.157, 95% CI 0.059 to 0.254) were both associated with higher skeletal muscle mass in adolescents; however birth weight and mother’s place of birth had no influence on pubertal skeletal muscle composition. Higher pubertal muscle mass and testosterone are association with better glucose metabolism in adolescence. Food intake and physical activity may also influence the development of skeletal muscle, thus adolescence may be a sensitive period for the development of diabetes where interventions to increase muscle mass could have long-term protective effects. / published_or_final_version / Public Health / Master / Master of Philosophy

Three studies were designed to investigate the hypothesis that physiological and environmental variables are both independent and interactive in determining food intake (FI) in children and adolescents during puberty (8 – 18 y old). Study 1 investigated the effect of obesity, sex and pubertal status on appetite hormones in response to a mixed glucose and whey protein (WP) drink in adolescents. Obese adolescents had higher insulin, PYY and lower ghrelin than normal weight (NW) controls, with a more pronounced effect in males. Puberty did not affect insulin, but the change in PYY in response to the drink was greater and ghrelin was lower in mid-late pubertal than pre-early pubertal obese males. To further describe the role of puberty, Study 2 examined the effect of pubertal status on FI following consumption of glucose and WP drinks in male and female children. In mid-late pubertal children, mealtime compensation for energy from glucose was less at 60 than at 30 min, but not for whey. However, compensation for either drink was not different at 30 and 60 min meals in pre-early pubertal children. Finally to demonstrate the interaction between puberty and environmental influences on FI, Study 3 examined the effect of distraction (television viewing, TVV) while eating and pubertal status on food intake after a pre-meal glucose drink in girls. In Study 3, TVV had no effect on FI, however, glucose suppressed FI more with no TVV compared with TVV (24% vs. 10%). In postpubertal girls, glucose reduced FI by ~27% in both the no TVV and TVV conditions, but in peripubertal girls, reduction in FI was 22% without TVV and only 1% while TVV. Thus, the results of this research support the hypothesis that physiological and environmental variables are both independent and interactive in determining FI in children and adolescents during puberty.

Thesis (Ph.D.) - University of St Andrews, May 2008.

Orientador: Wilma De Grava Kempinas / Banca: Glaura Alves Scantamburlo Fernandes / Banca: Luis Fernando Barbisan / Acompanhado de 1 CD-ROM / Resumo: A puberdade constitui um período de rápidas e interativas alterações morfológicas, endócrinas e comportamentais. Atualmente a exposição à contaminantes ambientais tem sido implicada como um dos fatores responsáveis por alterações no desenvolvimento infantil, resultando em precocidade ou atraso na puberdade. Numerosos compostos químicos de uso doméstico, industrial e agrícola possuem comprovada atividade hormonal, sendo conhecidos com desreguladores endócrinos. Alguns clínicos estão começando a avaliar alguns parâmetros relacionados à interferência desses compostos no desenvolvimento de crianças residentes em áreas contaminadas, mas não há estudos correlacionando o atraso na puberdade masculina com possíveis alterações do trato reprodutivo e fertilidade a partir da maturidade sexual. Esse estudo objetivou investigar se o retardo na instalação da puberdade masculina compromete parâmetros reprodutivos na puberdade e as possíveis repercussões na fertilidade na vida adulta, utilizando o rato como modelo experimental. Tendo em vista ainda que na literatura existe um grande intervalo fixado para o início da puberdade, o trabalho pretendeu também analisar os parâmetros de puberdade do rato normal, contribuindo para o estabelecimento de uma idade real para a puberdade de ratos machos Wistar. Para tanto, foi provocado um atraso no início da puberdade mediante administração de dose alta de dibutil ftalato (DBP) durante o período fetal. Foram avaliados parâmetros morfofuncionais do trato reprodutivo masculino, dosagens hormonais, avaliações espermáticas, além de análises histopatológicas e morfométricas do testículo e epidídimo. Na puberdade, houve diminuição significativa do peso da próstata dos animais expostos ao DBP, além de redução da produção diária de espermatozóides... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Puberty is a period of fast and interactive morphological, endocrine and behavioral changes. Currently, the exposure to environmental contaminants is considered one of the factors responsible for alterations in child development, resulting in pubertal precocity or delay. Many chemical compounds with domestic, industrial and agricultural use, known as endocrine disruptors, have shown hormonal activity. Some clinicians are beginning to evaluate some parameters related to the interference of these compounds in the development of children living in contaminated areas, but there are no studies correlating this delay on puberty with possible changes in the reproductive tract and fertility from sexual maturity. This study aimed to investigate whether a delay in puberty installation affects reproductive parameters in pubertal and adult male rats. Especially considering that the literature shows a wide range fixed for the beginning of puberty, the study also intended to analyze the parameters of puberty in normal rats, contributing to the establishment of an actual age for puberty in male Wistar rats. The onset of puberty was delayed through administration of a high doses of dibutyl phthalate (DBP) during the fetal period. We assessed morphofunctional parameters of the male reproductive tract, hormonal levels, sperm evaluations, and histopathologic and morphometric analysis of testis and epididymis. At puberty, the prostate weight of DBP-exposed animals was significantly reduced. The daily sperm production was reduced in the testis of the pubertal DBP-exposed rats, and this alteration remained in the adult rats. However, neither sperm morphology nor sperm motility was altered, as well as the capacity of fertilization assessed by AI. The histopathology of testis revealed a high number of tubules with... (Complete abstract click electronic access below) / Mestre

Body adiposity is generally considered the most pertinent factor in puberty attainment; however, recent data suggests that pre-pubertal reproductive tract development may be altered by dietary sugar consumption. Two experiments were conducted to delineate the direct effects of fructose on the maturation of the pre-pubertal reproductive tract and fertility. At three weeks of age, forty gilts were placed on one of five dietary treatments (n=8) containing 15% fat (FAT), 35% fructose (FRU), both fat and fructose (HFHF), or two different controls: one standard industry (IND) diet meant to result in optimal lean growth and a second diet to account for the reduced lysine (LYS) intake in the treatment diets. Body weights did not differ amongst any of the five treatments on the day of sacrifice (P=0.32). As a percentage of BW, total reproductive tracts were heavier in fructose fed gilts (1.3±0.1 v. 0.8±0.1%; P=0.01) compared to non-fructose gilts. In the second experiment, starting at 130d of age, gilts were checked twice daily for puberty attainment. Gilts that attained puberty were artificially inseminated (AI) on their third estrous cycle. On gestational day 38±3, pregnant gilts were harvested for reproductive tract collection. Fewer fructose fed (FRU and HFHF) pigs became pregnant than non-fructose fed (IND, LYS, and FAT) gilts (25% v. 75% respectively; P=0.03). All HFHF gilts failed to become pregnant. Placental weights were greater in LYS fetuses than FAT fetuses (79.07 ± 6.55g v. 47.26 ± 6.45g, respectively, P= 0.04). Taken together, these results demonstrate that fructose consumption increases reproductive tract size, but that reproductive capabilities are reduced. / Master of Science

O objetivo deste estudo foi avaliar a influência da suplementação proteica no terço final da gestação de vacas Nelore e das bezerras em creep-feedingsobre o desempenho produtivo e reprodutivo de bezerras e novilhas. Para tanto, foi utilizado um arranjo fatorial (2X2), sendo o fator I a suplementação das vacas no terço final de gestação (n=350) e o fator II a suplementação das bezerras em creep-feeding (n=153). No terço final da gestação, as vacas foram suplementadas com 0,5 kg de farelo de soja, e as bezerras foram suplementadas em creep-feeding a partir dos 30 dias após o nascimento até a desmama, aos 6,38 meses de idade. O período experimental compreendeu do terço final da gestação até os 30 meses de idade. Não houve interação entre as estratégias de suplementação sobre o peso corporal (P=0,66) e ECC (P=0,58) das vacas, e sobre o peso corporal (P=0,62) e GMD (P=0,73) das bezerras dos 1,2 até 26,0 meses. Da mesma forma, não houve efeitoo da suplementação das vacas (P=0,98) e das bezerras em creep-feeding (P=0,78) sobre o peso das bezerras. Entretanto, a suplementação das vacas influenciou pontualmente o peso das novilhas aos 24,9 meses, sendo que as novilhas filhas de vacas suplementadas foram mais pesadas (P=0,040). A taxa de puberdade aos 12,5 (P=0,31) e 24,9 (P=0,75) meses e a taxa de prenhez aos 18,7 (P=0,86) e 26,0 (P=0,36) meses não foram influenciados por nenhuma das estratégias nutricionais. No entanto, houve interação entre a suplementação das vacas e das bezerras em creep-feeding sobre a taxa de prenhez aos 30 meses de idade, sendo que novilhas filhas de vacas suplementadas no terço final da gestação e que foram suplementadas em creep-feeding apresentaram maior taxa de prenhez (92%, P=0,019) quando comparadas com novilhas que receberam apenas um dos dois tipos de suplementação. A associação entre suplementação materna no terço final de gestação e a suplementação na fase de cria (creep-feeding) não impactaram sobre o peso corporal, GMD, taxa de puberdade das novilhas. / The objective of this study was to evaluate the influence of dam supplementation on least trimester of gestation of Nellore cows and creep-feeding supplementation on productive and reproductive performance of heifers. For this purpose, a factorial arrangement (2X2) was used, which the factor I was dam supplementation of cows in the least trimester of gestation (n = 350) and the factor II was creep-feeding supplementation (n = 153). Cows were supplemented with 0.5 kg of soybean meal by 90 days before partum, and the female calves were supplemented in creep-feeding from 30 days after birth until weaning at 6.38 months of age. The experimental period comprised the least trimester of gestation up to 30 months of age. There was no interaction between supplementations on body weight (P = 0.66) and BCS (P = 0.58) of cows, and on body weight (P = 0.62), and ADG (P = 0.73) of heifers from 1.2 to 26.0 months. In the same way, there was no effect of dam supplementation (P = 0.98), and creep-feeding (P = 0.78) on body weight of heifers. However, dam supplementation exerted punctual influence on body weight of heifers at 24.9 months of age, when heifers that dam were supplemented were heavier (P = 0.040). The reproductive parameters such puberty rate at 12.5 (P = .31) and 24.9 (P = 0.75) months and the pregnancy rate at 18.7 (P = 0.86) and 26.0 (P = 0.36) months were not influenced by any nutritional strategies. However, there was interaction between supplementations on the pregnancy rate at 30 months of age, which heifers from cows that received supplement on least trimester of gestation and were submitted to creep-feeding showed higher pregnancy rate (92%, P = 0.019) than heifers who received only one of two types of supplementation. The association between dam supplementation and creep-feeding did not affect body weight, ADG, and puberty onset in Nellore heifers.

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