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1
Bovard, Joshua Maschio. "Does competitive swimming during puberty affect lung development in pubertal females?" Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62896.
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Whether the large lungs of competitive swimmers result from intensive swim training or genetic endowment has been widely debated. Given that peak growth velocities for the lungs occur during puberty, this longitudinal study aimed to determine if competitive swimming during puberty affected lung development. Female swimmers (n=11) and healthy controls (n=10) aged 11-14 years old were assessed before and after one competitive swimming season. Pulmonary function testing included lung volumes, spirometry, diffusion capacity (DL,CO), and maximal inspiratory (PIMAX) and expiratory (PEMAX) pressures. Ventilatory constraints, including end-expiratory lung volume (EELV), expiratory flow limitation (EFL), and utilization of ventilatory capacity (V̇E/V̇ECAP), were assessed during an incremental cycling test. Despite being of similar age (p=0.10), maturational development (p=0.27), and height (p=0.38) as controls, swimmers had a larger total lung capacity (p<0.01), forced vital capacity (p<0.01), and peak expiratory flow (p=0.03). Although DL,CO was greater in swimmers (p=0.01), there was no difference when expressed relative to alveolar volume (p=0.20). Both PIMAX (p=0.06) and PEMAX (p<0.001) were greater in swimmers. Swimmers and controls achieved a similar relative maximal oxygen consumption (p=0.32) and experienced similar ventilatory constraints as characterized by EELV (p=0.18), severity (p=0.95) and prevalence (p=0.71) of EFL, and V̇E/V̇ECAP (p=0.95). Changes over time were similar between groups (p>0.05). Pubertal female swimmers already had larger lung capacities, higher flows, and greater indices of respiratory muscle strength, but similar ventilatory constraints while cycling. One competitive swimming season did not further accentuate this enhanced function or alter exercise ventilatory mechanics, suggesting that competitive swimming during puberty did not affect lung development.Education, Faculty of
Kinesiology, School of
Graduate
2
Cohen, Robin Zoe. "Puberty and scizophrenia". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0003/MQ40801.pdf.
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Jeffreys, Renee M. Ph D. "Physical Activity and Pubertal Onset: Longitudinal Analysis of the Puberty Study Cohorts". University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406820304.
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Lee, Bo Yeon. "Action of manganese on puberty". Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/5871.
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Manganese (Mn) is considered important for normal growth and reproduction. Because Mn can cross the blood brain barrier and accumulate in the hypothalamus, and because it has been suggested that infants and children are potentially more sensitive to Mn than adults, we wanted to determine the effects of Mn exposure on puberty-related hormones and the onset of puberty, and discern the site and mechanism of Mn action. We demonstrated that the central administration of manganese chloride (MnCl2) stimulated luteinizing hormone (LH) release in prepubertal rats. Incubation of medial basal hypothalamus (MBH) in vitro showed this effect was due to a Mn-induced stimulation of luteinizing hormone releasing hormone (LHRH). Further demonstration that this is a hypothalamic site of action was shown by in vivo blockade of LHRH receptors and the lack of a direct pituitary action of Mn to stimulate LH release in vitro. Chronic supplementation of low dose of MnCl2 caused elevated serum levels of LH, follicle stimulating hormone (FSH) and estradiol or testosterone. Importantly, Mn supplementation advanced the timing of puberty in both sexes. We investigated the mechanism by which Mn induces LHRH/LH release from the hypothalamus. Blocking the NMDA receptor, IGF1 receptor, or inhibiting nitric oxide synthase in vivo was ineffective in altering Mn-induced LH release. Dose-response, pharmacological blockade and nitrite assessments indicated that the lowest doses of Mn used stimulated LHRH release, but did not induce nitric oxide (NO) production, while only the highest dose of Mn stimulated NO. Conversely, a dose-dependent inhibition of Mn-induced LHRH release was observed in the presence of ODQ, a specific blocker of soluble guanylyl cyclase. Furthermore, Mn stimulated the release of cyclic GMP (cGMP) and LHRH from the same MBH, and a protein kinase G (PKG) inhibitor, KT5823, blocked Mn-induced LHRH release. Collectively, these data demonstrate that Mn can stimulate specific puberty-related hormones both acutely and chronically, and furthermore, suggest that low levels of Mn facilitate the normal onset of puberty. The principal action of Mn within the hypothalamus is to facilitate the activation of guanylyl cyclase, which subsequently stimulates the cGMP/PKG pathway resulting in the stimulation of prepubertal LHRH secretion.
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Balzer, Ben William Robert. "NOVEL WAYS OF ASSESSING PUBERTY". Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/21771.
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Puberty involves profound anthropometric and hormonal changes that have been associated with changes in mood, behaviour and other health risks that emerge in adolescence. However, there is little longitudinal research in the effects of puberty on adolescents. The overarching aim of this thesis was to demonstrate novel ways of studying puberty and how these improve our understanding of the longitudinal changes that occur over this period. Oestradiol is popularly associated with changes in mood and depression and testosterone with aggression and risk taking. Chapters 3 and 4 reviewed the effects of oestradiol on female, and testosterone on male adolescent mood and behaviour. In both reviews there were inconsistent cross-sectional data, and limited longitudinal data, supporting such associations. In Chapter 5, text messaging reminders for study compliance was studied. Specimen collection correlated with text message reply time. Liquid chromatography-tandem mass spectrometry assays on urine and serum specimens quantified oestradiol, testosterone and luteinising hormone levels in 97% of urine and 95% of serum specimens (Chapter 6). Hormone changes over one year were not linear, with frequent urine sampling offering a more nuanced description of puberty hormone change. Self-rated Tanner stage and other subjective measures of puberty (adolescent- and parent-rated) were compared with longitudinal changes in serum hormones in Chapter 7. Positive longitudinal associations were observed between these subjective measures and hormone changes. Chapter 8 identifies foot length growth as a novel marker for early puberty changes. Positive longitudinal relationships were observed between foot length, height, weight, Tanner stage and serum sex steroids. Foot length offers a practical, novel and cost-effective marker of early puberty. This thesis provides novel insights into puberty and adolescence, particularly how this life transition is studied. The importance of longitudinal research to determine the true effects of puberty hormone changes on adolescents is highlighted, and data are provided to show how this can be feasibly achieved.
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Kim, Kenneth. "Family structure, puberty and reproductive development". Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266838.
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Mobley, Stacey Lloyd. "Calcium kinetics in girls during puberty /". The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488191667183775.
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Paczkowski, Melissa Jeanne. "Effects of experimental fascioliasis on puberty and comparison of mounting activity by radiotelemetry in pubertal and gestating beef heifers". Texas A&M University, 2004. http://hdl.handle.net/1969.1/2796.
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Angus-sired heifers were allotted by age (mean=4 mo), BW (mean=135 kg), and sire (n=4) to either a control (n=10) or infected group (n=11; 600 metacercariae of Fasciola hepatica, intraruminally) to test our hypothesis that puberty is delayed by experimental fascioliasis. Blood samples were collected biweekly for analysis of steroid hormone concentrations. At 2-wk intervals, BW was recorded, and samples were collected for analysis of liver enzymes and serum proteins and fecal egg counts. A radiotelemetry system (HeatWatch??) was used to detect estrus and ovulation was confirmed by an elevation in serum progesterone (P4) after estrus. Heifers were artificially inseminated (AI) at the second observed estrus. Serum γ-glutamyl transpeptidase (GGT) and aspartate aminotransferase (AST) increased (p<0.0008) between day 0 and 112 in the infected group. Serum estradiol (E2) and P4 concentrations did not differ (p>0.1) between treatment groups. Mean age at puberty was 10 days later (p>0.1) in the infected group. Conception rate did not differ between control and infected heifers.
The HeatWatch?? data were used to compare mounting activity during estrus in pubertal and gestating heifers. Mean duration of estrus was longer (p<0.01) for the second than for the pubertal estrus, though total mount duration and number of mounts did not differ. Number of mounts at second estrus was greater (p<0.05) for heifers that conceived (n=9). Mean duration of estrus and total mount duration at second estrus were not associated with pregnancy outcome. Estrus events were detected in all nine heifers during pregnancy (total=73). A majority (75%) of the interestrus intervals during gestation was <17 d. Number of mounts (p=0.035) and total duration of mounts (p=0.022) at second estrus were predictive of number of mounts during gestation.
Experimental infection of Fasciola hepatica did not alter serum steroid hormone concentration or delay pubertal development in heifers. Estrus duration was longer for the second estrus compared to the pubertal estrus, and the number of mounts received during the second estrus was greater in heifers that did conceive to AI. Estrus events were detected in each heifer during pregnancy; however, a normal interestrus interval occurred in only 10% of the estrus events.
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Patterson, Jennifer Lynne. "Factors influencing onset of puberty in gilts". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ60485.pdf.
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Bridges, Nicola Anne. "The endocrine and physical events of puberty". Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295696.
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Maquivar, Martin G. "Nutritional Regulation of Precocious Puberty in Heifers". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322586535.
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Hess, Monna Fay. "Steroidogenesis in the equine testis throughout puberty /". For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Rubio, Abadal Elena. "Factors del neuro-desenvolupament i de la pubertat que es relacionen amb l'edat d'inicide primers episodis de psicosi". Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/397730.
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Introducció: Estudis previs han demostrat que una edat d'inici de psicosi (EIP) precoç s'associa a major gravetat clínica i funcional i pitjor pronòstic. El coneixement en profunditat de l'EIP pot contribuir a una milloria del coneixement de l'etiopatogènia i a poder dirigir de forma específica el tractament precoç de la psicosi. Hi ha diversos factors genètics i ambientals que s'ha demostrat poden fer variar l'EIP, com l’edat de la pubertat, complicacions obstètriques, antecedents familiars o ús de substàncies.
Objectius: Amb el present projecte es vol estudiar com es relacionen aquests factors i l'EIP en una mostra de pacients amb un primer episodi de psicosi. Al primer treball l’objectiu és relacionar, en la submostra de dones, l’edat de menarquia, com a mesura de pubertat, amb l’EIP, i estudiar la relació entre l’edat de menarquia i la gravetat i el pronòstic clínics. Al segon treball, determinar la relació entre EIP i antecedents de complicacions de tipus obstètric i dades al néixer com el baix pes o la prematuritat fetal, i avaluar com es relacionen amb l'EIP els antecedents familiars de psicosi i l’edat del pare i de la mare.
Mètodes: Es van reclutar per aquest estudi pacients d'entre 10 i 65 anys amb un primer episodi psicòtic, atesos tant a serveis de salut mental comunitaris com d’hospitalització i pertanyents a les xarxes d'adults o d'infanto-juvenil. La mostra final va ser de 90 pacients. Per a realitzar aquest estudi es va crear un qüestionari sòcio-demogràfic, completat a través d'entrevista clínica, i es varen administrar les següents escales: PANSS (Positive and Negative Syndrome Scale), ICG-ESQ (Clinical Global Impression – Schizophrenia Scale), GAF (Global Assessment of Functioning), DAS-sv (Disability Assessment Schedule versió curta), escala d'Intel·ligència de Wechsler, i escala EuroQol 5D de qualitat de vida. Es va obtenir l'edat decimal del/la pacient en l'inici dels primers símptomes psicòtics, en el primer contacte amb psiquiatria i en el primer ingrés a hospital psiquiàtric, si n’era el cas. L'edat de menarquia es va obtenir de forma retrospectiva.
Mitjançant entrevista clínica i el qüestionari dissenyat per a l'estudi es va obtenir a més a més l'edat del pare i de la mare en el moment del naixement del fill/a i l'ús de substàncies previ al debut de psicosi (criteris d'abús i dependència del DSM-IV). Els antecedents de psicosi en la mare o pare es varen recollir seguint el model d'Andreasen i els antecedents obstètrics utilitzant l'escala de complicacions obstètriques de Lewis i Murray. També es recollí el pes i edat gestacional del o la pacient al néixer, i si la mare havia patit avortaments previs o havia consumit substàncies durant l'embaràs.
Resultats: No es va trobar una correlació estadísticament significativa entre l’edat de menarquia i EIP. Tampoc es varen trobar dades significatives en quant a la relació entre l'edat de menarquia i l'escala PANNS, ICG-ESQ, GAF, DAS total o EuroQol. La pre-eclàmpsia, la necessitat d'ús d'incubadora en néixer, l'ús de fòrceps, l'antecedent patern de psicosi i un pes baix en néixer, es van relacionar amb una edat de EIP més primerenca. L’ús de fòrceps i el pes en néixer eren les variables que millor predeien l’EIP.
Conclusions: Els resultats obtinguts suggereixen una major complexitat de la hipòtesi estrogènica, involucrant altres factors com biològics i psicosocials,
i posen en relleu el rol del període prenatal en el desenvolupament de la psicosi i la importància de monitoritzar de forma adequada l'embaràs i el part, especialment en casos de mares i pares amb antecedents de psicosi.
Factors de risc com la càrrega familiar i genètica, complicacions al part i embaràs i l’ús de tòxics durant l’adolescència podrien ser utilitzats de forma efectiva com predictors de trastorns psicòtics.Introduction: Previous studies have shown that age at onset of psychosis (AOP) is associated with higher clinical and functional severity and worse prognosis. An in-depth study of AOP can contribute to the improvement of knowledge of psychosis pathogenesis and help improve its early and specific treatment. There are several genetic and environmental factors that have been related to AOP variations such as age of puberty, obstetric complications, family history or substance use. Objectives: The purpose of this project is to study how these factors relate to AOP in a sample of patients with a first episode of psychosis. The objective of the first study is to relate, in the women subsample, the age of menarche, as a measure of puberty, with AOP, and to study the relationship between age of menarche and clinical severity and prognosis. In the second study, the objective is to determine the relationship between AOP and history of obstetric complications, low birth weight and preterm birth and to evaluate how family history of psychosis and age of parents relate to AOP. Methods: Patients included in the the study were aged between 10 and 65 years old, with a first psychotic episode, both recruited in community and hospital facilities, and belonging to adults or children and adolescent mental health services. The final sample was of 90 patients. For this study a socio-demographic questionnaire was designed, completed through clinical interview, and the following scales were administered: PANSS (Positive and Negative Syndrome Scale) ICG-ESQ (Clinical Global Impression - Schizophrenia Scale), GAF (Global Assessment of Functioning) sv-DAS (Disability Assessment Schedule short version), Wechsler Intelligence scale and EuroQol 5D quality of life scale. We obtained the decimal ages of onset of psychotic symptoms, of first contact with psychiatry and of first admission to a psychiatric hospital, if that was the case. Age of menarche was obtained retrospectively. Through clinical interview and the questionnaire designed for the study, ages of the father and the mother at time of child birth and substance use prior to the psychosis onset (DSM-IV abuse and dependence criteria) were also obtained. The history of psychosis in the mother or father was collected following the Andreasen model and obstetric antecedents using the scale of Lewis and Murray obstetric complications. Also weight and gestational age of the patient at time of birth were collected, and whether the mother had experienced previous miscarriages or had used any substances during pregnancy. Results: A significant correlation between age of menarche and AOP, PANSS scale, ICG-ESQ, GAF, total DAS or EuroQol was not found. Pre-eclampsia, need of incubator at birth, use of forceps, paternal history of psychosis and low birth weight, were associated with an earlier AOP. Use of forceps and birth weight were the variables that best predicted AOP. Conclusions: The results suggest a greater complexity of estrogen hypothesis, involving other factors such as biological and psychosocial ones, and highlight the role of the prenatal period in the development of psychosis and the importance of adequately monitor pregnancy and delivery, especially in cases of parents with a history of psychosis. Risk factors such as genetic and family burden, pregnancy and childbirth complications and the use of substances during adolescence could be used effectively to predict psychotic disorders.
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Evuarherhe, Obaro. "Gender, puberty and the hypothalamic-pituitary-adrenal axis". Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.618813.
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The hypothalamo-pituitary-adrenal (HPA) axis, a neuroendocrine pathway involved in the stress response is well studied in both human beings and rodents. Major gender-related neuroendocrine changes take place during pubcl1y (days 30 - 60 in rats) including a robust increase in the levels of gonadal steroids which are thought to underlie numerous neural and behavioural changes brought on after puberty. Evidence suggests the HPA axis undergoes significant changes over the pubertal period. This project investigated the effects of gonadal steroids on the HPA axis before and after puberty and the role of the pubertal surge in endogenous gonadal steroids in both sexes; specifically looking at the sensitivity of the resulting adult HPA axis to exogenous gonadal steroids. There was a significant effect of both age and sex on the adrenocorticotrophic hormone (ACTH) and corticosterone response to restraint stress. Sexual dimorphism in the endocrine stress response became more pronounced after puberty. Adult physiological levels of gonadal steroids reduced the corticosterone and ACTH response to restraint stress in both male and female prepubertal rats. In adult males, testosterone reduced the ACTH response to stress while in adult females, there was a s significant effect of ovariectomy (OVX) on the stress response. 1:estosterone treatment did not significantly affect overall corticosterone release over the 24hr period in adult animals castrated (CSX) before puberty. In contrast, testosterone significantly suppressed corticosterone secretion in animals CSX in adulthood. Animals CSX prepubertally displayed significantly lower glucocorticoid receptor levels in the dentate gyrus of the dorsal hippocampus than animals CSX in adulthood. [n females, prepubertal OVX did not affect the ability of oestradiol to affect basal HPA activity in adulthood. Overall, the data suggest vital roles of peripubertal gonadal steroids on the adult HPA axis; although the pubertal maturation of the female HP A phenotype appears to be independent of peripubertal oestrogens.
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Baxter-Jones, A. D. G. "Physical effects of training during puberty and adolescence". Thesis, University of Aberdeen, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261591.
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Élite adult athletes are known to have physical and physiological characteristics specifically suited to their sport. However, it is not clear whether the observed adult differences arise because of training or whether the sport selects the individual with the appropriate characteristics.The purpose of this study was to compare and contrast the physical development of young athletes (8 - 19 yr) and in so doing provide an answer to this question. Development of anthropometric characteristics, sexual maturation, pulmonary function and aerobic power were assessed in a group of 232 boys and 222 girls. The athletes were a randomly selected group of young athletes who had demonstrated previous performance success or who were excepted to do so in the future. They came from 4 sports namely: soccer (all male); gymnastics (2:1 female to male ratio), swimming (1:1 sex ratio) and tennis (1:1 sex ratio). The subjects were assessed annually for three consecutive years. The adjusted mean (ANCOVA) height of male swimmers (161.6 ± 0.6 cm) was found to be significantly greater (P<0.01) than non-athletes (159.2 ± 0.4 cm), gymnasts (150.7 ± 0.8 cm) and soccer players (158.7 ± 0.6 cm) and adjusted body mass (51.3 ± 0.6 kg) significantly greater (P<0.01) than the other groups. These trends were also observed in females. When testicular volumes were compared, it was found that swimmers matured significantly earlier (P<0.05) than gymnasts, tennis players and a reference population of non athletes. Female gymnasts attained sexual maturation (indexed by menarche) on average (14.4 ± 0.2 yr) a year after the other sports and the general population. A positive correlation was found between menarcheal age in mothers and daughters (r=0.29 , P<0.05), suggesting a familial trait. The observed late sexual maturation of gymnast therefore suggests some form of sports specific selection. Swimmers had the highest initial lung volumes (P<0.001), a difference which did not change with time. However, as training began well before the subjects were tested it was not possible to determine whether these observed differences were present prior to training. When age, height and weight were controlled for VO2 max in males significantly increased both pubertal development, although this pattern was not shown in females. Swimmers had the highest VO2 max values at all ages.
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Howard, Sasha. "Investigation of the genetic regulation of delayed puberty". Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/28165.
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The genetic control of puberty remains an important but mostly unanswered question. Late pubertal timing affects over 2% of adolescents and is associated with adverse health outcomes. Self-limited delayed puberty (DP) segregates in an autosomal dominant pattern and is highly heritable; however, its neuroendocrine pathophysiology and genetic regulation remain unclear. The genetic control of puberty remains an important but mostly unanswered question. Late pubertal timing affects over 2% of adolescents and is associated with adverse health outcomes. Self-limited delayed puberty (DP) segregates in an autosomal dominant pattern and is highly heritable; however, its neuroendocrine pathophysiology and genetic regulation remain unclear. Our large, accurately phenotyped cohort of patients with familial self-limited DP is a unique resource with a relatively homogeneous genetic composition. I have utilised this cohort to investigate the genetic variants segregating with the DP trait in these pedigrees. Whole exome sequencing in eighteen probands and their relatives, and subsequent targeted sequencing in an extended subgroup of the cohort, has revealed potential novel genetic regulators of pubertal timing. In ten unrelated probands, I identified rare mutations in IGSF10, a gene that is strongly expressed in the nasal mesenchyme during embryonic migration of gonadotropin-releasing hormone (GnRH) neurons. IGSF10 knockdown both in vitro and in a transgenic zebrafish model resulted in perturbed GnRH neuronal migration. Loss-of-function mutations in IGSF10 were also identified in five patients with absent puberty due to hypogonadotropic hypogonadism (HH). Additionally, I have identified and investigated one rare, pathogenic mutation in HS6ST1 - a gene known to cause HH - in one family with DP, and two rare variants in FTO - a gene implicated in the timing of menarche in the general population - in 3 families. Further potentially pathogenic variants have emerged from investigating candidate genes identified from microarray studies (LGR4, SEMA6A and NEGR1) and from related clinical phenotypes (IGSF1). Our large, accurately phenotyped cohort of patients with familial self-limited DP is a unique resource with a relatively homogeneous genetic composition. I have utilised this cohort to investigate the genetic variants segregating with the DP trait in these pedigrees. Whole exome sequencing in eighteen probands and their relatives, and subsequent targeted sequencing in an extended subgroup of the cohort, has revealed potential novel genetic regulators of pubertal timing. In ten unrelated probands, I identified rare mutations in IGSF10, a gene that is strongly expressed in the nasal mesenchyme during embryonic migration of gonadotropin-releasing hormone (GnRH) neurons. IGSF10 knockdown both in vitro and in a transgenic zebrafish model resulted in perturbed GnRH neuronal migration. Loss-of-function mutations in IGSF10 were also identified in five patients with absent puberty due to hypogonadotropic hypogonadism (HH). Additionally, I have identified and investigated one rare, pathogenic mutation in HS6ST1 - a gene known to cause HH - in one family with DP, and two rare variants in FTO - a gene implicated in the timing of menarche in the general population - in 3 families. Further potentially pathogenic variants have emerged from investigating candidate genes identified from microarray studies (LGR4, SEMA6A and NEGR1) and from related clinical phenotypes (IGSF1).
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Goddings, A. M. "The impact of puberty on adolescent brain development". Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1468921/.
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Research has demonstrated that the human brain undergoes significant change in both structure and function during adolescence, but little is known about the role of puberty in this developmental process. The aim of this thesis is to investigate the relationship between puberty and brain development during adolescence. The first two chapters of this thesis summarise the current understanding of the behavioural and brain changes associated with both adolescence and puberty, and review the methods employed to assess puberty in research. Chapters 3 and 4 focus on the relationship between puberty and changes in brain structure. In Chapter 3, the influence of puberty on subcortical structural development is investigated in a large longitudinal MRI dataset, using a mixed effects modelling analysis method. Chapter 4 investigates the relationship between pubertal status, as measured by physical pubertal stage and levels of salivary sex steroid hormones, and white matter structural development in a cross-sectional sample of 12-16 year old boys, using diffusion tensor imaging. In Chapters 5-7, functional brain changes with puberty are explored. Chapters 5 and 6 focus on social emotion processing, where social emotions (e.g. embarrassment) are defined as emotions that require an awareness of other people’s mental states, while basic emotions (e.g. fear) are those which do not. In Chapter 5, the neural correlates of social and basic emotion processing are investigated in relation to pubertal status. In Chapter 6, the fMRI data are reanalysed using psycho-physiological interaction (PPI) analysis to investigate puberty-related changes in functional connectivity during the same task. Chapter 7 explores, in males, how developmental changes in brain function when performing a risk-taking task are related to puberty, independently of chronological age. Finally, in Chapter 8, the results of the empirical studies are summarised and the findings and implications of the thesis are discussed.
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Houghton, Lauren Claire. "Juvenility, puberty and adolescence among Bangladeshi and British youth". Thesis, Durham University, 2013. http://etheses.dur.ac.uk/6958/.
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The ABBY (Adolescence among Bangladeshi and British Youth) Project explores the relationship between migration and growing up from a biocultural perspective. Based on evolutionary hypotheses, it tests for facultative adaptation to different developmental environments during the transition from child to adolescent using contrasting conditions within ethnicity, ecology, and migration. I explore the relationship between these variables and the timing and tempo of adrenarche, thelarche, pubarche and menarche through comparisons of biological and cultural markers of development among 488 girls, aged 5–16, belonging to the following groups: Sylheti, first generation British-Bangladeshi, second generation British-Bangladeshi and white British. This project supports evidence that the timing, tempo and experience of juvenile and pubertal development vary across populations with possible lasting implications for the strategic allocation of reproductive effort. Specifically, adrenarche occurred two years earlier in first generation migrant girls to Britain, suggesting that change in ecological factors results in more rapid juvenile onset. Thelarche occurred earlier with increasing individual and ancestral generations lived in the UK, suggesting that local ecological factors result in earlier pubertal onset. Contrary to predictions, menarcheal timing and oestrogen levels did not differ significantly among groups. Acculturation did not account for differences in behaviours during juvenile and pubertal development between groups. Instead, the stages of practising to being dedicated to hijab (which occur during juvenility and after puberty, respectively) better reflect the social process of growing-up as Bangladeshi girls in East London. Growing up here may be uniquely stressful among first generation migrants. Psychosocial stress may interact with other ecological factors resulting in an overall slower tempo of juvenile development. The extended period of plasticity during juvenility among girls who experienced a change in socio-ecological factors may be an adaptive response to ensure a better tracking of current socio-ecological conditions and also a better prediction of later ones.
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Cho, Yoon Hi. "AUTONOMIC DYSFUNCTION, OBESITY AND PUBERTY IN TYPE 1 DIABETES". Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16471.
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Autonomic dysfunction can occur after a short diabetes duration, and in adolescents with type 1 diabetes. Whilst autonomic neuropathy is known to be a major risk factor for morbidity and mortality in adults with diabetes, subclinical autonomic neuropathy remains poorly understood and often neglected in the complications assessment of adolescents with type 1 diabetes. This thesis focuses on factors contributing to cardiac autonomic dysfunction in adolescents with type 1 diabetes and their role in the early phase of pathogenesis of the chronic diabetes complications. In particular, the contributions of glycaemia and non-glycaemic factors of adiposity and puberty are explored in the following papers included in this thesis. In Paper 1, skin autofluorescence, a non-invasive measure of accumulated advanced glycation end-products (AGEs) implicated in diabetic vascular pathobiology, was significantly associated with the presence of retinopathy and cardiac autonomic neuropathy, independent of concurrent HbA1c levels. Moreover, skin autofluorescence was associated with long term average HbA1c for up to 10 years in adolescents with type 1 diabetes; potentially providing a clinical measure of metabolic memory of longer term glycaemic control. In Paper 2, cardiac autonomic dysfunction was associated with worse glycaemic control and markers of insulin resistance in adolescent girls with type 1 diabetes. Paper 3 found higher body mass index (BMI) and central adiposity to be independent predictors for cardiac autonomic dysfunction in a four year longitudinal study of adolescents with type 1 diabetes. Paper 4 demonstrated in a multicentre international cohort stratified for their risk of diabetic nephropathy, adolescents with high risk urinary albumin:creatinine phenotype already had evidence of a worse cardiac autonomic profile; independent of age and HbA1c levels. Paper 5 is a review of the factors during puberty which may modify the risk of diabetes complications. Interventions targeting early autonomic dysfunction in type 1 diabetes, particularly during the critical pubertal years, may potentially reduce the risk of future complications in later life.
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Vetter, Nora C., Mandy Drauschke, Juliane Thieme y Mareike Altgassen. "Adolescent Basic Facial Emotion Recognition Is Not Influenced by Puberty or Own-Age Bias". Frontiers Research Foundation, 2018. https://tud.qucosa.de/id/qucosa%3A31831.
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Basic facial emotion recognition is suggested to be negatively affected by puberty onset reflected in a “pubertal dip” in performance compared to pre- or post-puberty. However, findings remain inconclusive. Further, research points to an own-age bias, i.e., a superior emotion recognition for peer faces. We explored adolescents’ ability to recognize specific emotions. Ninety-five children and adolescents, aged 8–17 years, judged whether the emotions displayed by adolescent or adult faces were angry, sad, neutral, or happy. We assessed participants a priori by pubertal status while controlling for age. Results indicated no “pubertal dip”, but decreasing reaction times across adolescence. No own-age bias was found. Taken together, basic facial emotion recognition does not seem to be disrupted during puberty as compared to pre- and post-puberty.
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Largier, Damian Douglas Christopher. "Pubertal development in urban Xhosa schoolgirls". Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/26625.
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The present study was performed in order to update available data on puberty in South African women gathered from studies among a variety of South African population groups and to compare our findings with these previous studies in order to identify any change. In addition, the children's social environment was evaluated to see if it had any influence on the timing of puberty. This study is important because a decrease in the age of onset of the various stages of puberty would be expected as the socio-economic status of the population increases. We would expect that once socio-economic and therefore nutritional equality between different communities exists, there would be little difference between the age at which children attain puberty. An absence in the trend toward a younger onset of puberty would be a cause for concern as this would imply that there has been no improvement in living conditions from the time of the original study. A relationship has also been shown to exist between an earlier age at menarche and an increased risk of breast cancer (Pike 1983), an increased risk of coronary heart disease (Colditz 1987), shorter adult height (Shangold 1989), earlier initiation of sexual activity (Soefer 1985), earlier first pregnancy, (Sandler 1984) and larger family size (Frisch 1978). This implies that as the age at which children pass through puberty decreases, it becomes increasingly important to introduce both sexual education and the availability of contraception at a correspondingly earlier age in order to avoid the tragedies of teenage pregnancies.
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Gasser, Chad L. "Ovarian and endocrine dynamics associated with sexual maturation in beef heifers and the influence of diet, weaning age, and other factors during early reproductive development". The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1122295880.
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Jeffery, Alison Norah. "The impact of puberty on insulin resistance-a longitudinal study". Thesis, Exeter and Plymouth Peninsula Medical School, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.530386.
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Charmandari, Evangelia. "Congenital adrenal hyperplasia : the influence of puberty on cortisol pharmacokinetics". Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395379.
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Sumbung, Frederick Patta. "Ovarian function and response in prepubertal ewes through to puberty". Thesis, Sumbung, Frederick Patta (1985) Ovarian function and response in prepubertal ewes through to puberty. PhD thesis, Murdoch University, 1985. https://researchrepository.murdoch.edu.au/id/eprint/53694/.
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The objectives of this study were to assess ovarian function and responses to various reproductive stimuli in prepubertal ewe lambs, and to determine the hormonal patterns that accompany follicular activity through to puberty. Hormonal changes and occurence of oestrus were monitored in a group of young ewe lambs to establish at what age and bodyweight puberty occurred. A number of stimuli were then used to provoke ovarian and reproductive activity in groups of prepubertal ewe lambs.
Groups of ewe lambs were either placed with a ram, fed monensin supplement, primed with progesterone or challenged with FSH-P. Blood samples were collected to measure hormone levels and the lambs were ovariectomized to determine ovarian morphology and function. Follicles were dissected from the ovaries, antral fluid collected and the follicles were incubated in culture medium to measure steroid production. Gonadotrophin binding site present in the granulosa cells of the stimulated follicles was also quantified.
The natural onset of puberty in Corriedale ewe lambs was attained at the age of 40-42 weeks with a threshold bodyweight of 34-36 kg in the breeding season. Response of ewe lambs to the introduction of a ram seemed to depend on their age. ewe lambs aged 20-24 weeks showed no response whereas ewe lambs aged 34-36 weeks responded with increased LH pulse frequency and an LH surge which occured within 24 hours. The LH surge was followed by a transient increase in peripheral progesterone levels which lasted for 2-3 days, suggesting that ovulation had occurred but the resultant corpora lutea were short lived.
Monensin supplementation stimulated ovarian function with an increase in the number of small follicles and an increase in the antral fluid oestradiol content of large follicles. Progesterone priming caused an increase in oestradiol secretion into culture medium by large follicles. Withdrawal of progesterone treatment resulted in an increase LH pulse frequency. Neither of these treatments stimulated follicular maturation nor an LH surge.
After FSH stimulation, ewe lambs in control, monensin supplemented and progesterone-primed group showed a sharp increase in plasma LH levels. In control lambs the peak LH levels occured at intervals ranging from 12 h to 36 h after the initiation of FSH treatment, whereas in the progesterone-primed lambs the LH peak was later with tighter synchronization (36h to 42h). The monensin supplemented lambs showed an intermediate increase in LH levels with less synchrony (24h to 36h) than the progesterone-primed lambs following this FSH treatment. Both monensin supplemented and progesterone-primed lambs had a higher LH peak than control ewe lambs.
Ovariectomy after the LH surge but before ovulation showed that ovarian weight in progesterone-primed ewes was greater than in either control or monensin supplemented lambs. FSH treatment stimulated an increase in the development of large follicles in monensin supplemented and progesterone-primed ewe lambs. Follicles > 7mm in diameter secreted high levels of progesterone into culture medium, indicating that there was a shift in the steroidogenic capacity of the preovulatory follicles. Antral fluid from follicles of control lambs contained high levels of testosterone. Monensin supplementation and progesterone priming stimulated an increase gonadotrophin binding sites in granulosa cells after FSH in treatment.
Studies on ovaries removed after ovulation showed that monensin supplemented and progesterone-primed ewe lambs had more ovulations after FSH treatment and had significantly more functional corpora lutea 12 days after FSH treatment. Increased ovulations and increased numbers of functional corpora lutea were both associated with increased gonadotrophin binding sites. These result indicate a possible mechanism for the known influence of progesterone priming on the persistence of corpora lutea in ewes.
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Akyol, Pınar Dündar Bumin Nuri. "Isparta'daki kız çocuklarında ortalama puberte ve menarş başlama yaşlarının saptanması ve menarş başlama yaşını etkileyen faktörler ile menstrüal siklus özelliklerinin belirlenmesi /". Isparta : SDÜ Tıp Fakültesi, 2006. http://tez.sdu.edu.tr/Tezler/TT00297.pdf.
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Balzer, Ben. "NOVEL WAYS OF ASSESSING PUBERTY Findings from the Adolescent Rural Cohort Study of Hormones, Health, Education, Environments and Relationships". Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/21682.
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Puberty involves profound anthropometric and hormonal changes that have been associated with changes in mood, behaviour and other health risks that emerge in adolescence. However, there is little longitudinal research in the effects of puberty on adolescents. The overarching aim of this thesis was to demonstrate novel ways of studying puberty and how these improve our understanding of the longitudinal changes that occur over this period. Oestradiol is popularly associated with changes in mood and depression and testosterone with aggression and risk taking. Chapters 3 and 4 reviewed the effects of oestradiol on female, and testosterone on male adolescent mood and behaviour. In both reviews there were inconsistent cross-sectional data, and limited longitudinal data, supporting such associations. In Chapter 5, text messaging reminders for study compliance was studied. Specimen collection correlated with text message reply time. Liquid chromatography-tandem mass spectrometry assays on urine and serum specimens quantified oestradiol, testosterone and luteinising hormone levels in 97% of urine and 95% of serum specimens (Chapter 6). Hormone changes over one year were not linear, with frequent urine sampling offering a more nuanced description of puberty hormone change. Self-rated Tanner stage and other subjective measures of puberty (adolescent- and parent-rated) were compared with longitudinal changes in serum hormones in Chapter 7. Positive longitudinal associations were observed between these subjective measures and hormone changes. Chapter 8 identifies foot length growth as a novel marker for early puberty changes. Positive longitudinal relationships were observed between foot length, height, weight, Tanner stage and serum sex steroids. Foot length offers a practical, novel and cost-effective marker of early puberty. This thesis provides novel insights into puberty and adolescence, particularly how this life transition is studied. The importance of longitudinal research to determine the true effects of puberty hormone changes on adolescents is highlighted, and data are provided to show how this can be feasibly achieved.
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Delcour, Clémence. "Exploration des mécanismes étiopathogéniques des pathologies de la puberté". Electronic Thesis or Diss., Université Paris Cité, 2024. https://wo.app.u-paris.fr/cgi-bin/WebObjects/TheseWeb.woa/wa/show?t=6023&f=74391.
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Le développement de l'axe gonadotrope (HHG) débute pendant la vie foetale mais ne s'achève qu'une fois la puberté terminée. De nombreux acteurs interviennent à chaque étape et le défaut de l'un d'entre eux peut mener à des pathologies de la puberté ou des troubles de la fertilité à l'âge adulte. Les facteurs génétiques ont une place centrale dans le développement de l'axe HHG et l'étude génétique des pathologies de la puberté a permis des avancées majeures dans la compréhension des mécanismes moléculaires sous-jacents, bien qu'il subsiste toujours de nombreuses inconnues. Pour mon travail de thèse, j'ai choisi d'explorer la génétique des maladies de la puberté afin de mieux comprendre les mécanismes étiopathogéniques de ces maladies complexes. Dans un premier temps, j'ai eu l'opportunité d'étudier une famille consanguine au sein de laquelle deux soeurs présentaient une absence de puberté associée à une augmentation des concentrations d'oestradiol et des gonadotrophines. Nous avons mis en évidence un variant rare à l'état homozygote dans le récepteur alpha de l'oestradiol (ERalpha). L'étude in vitro du récepteur muté a montré une diminution de son activité régulatrice sur un promoteur contenant des éléments de réponse à l'oestradiol ainsi qu'une activation paradoxale ligand-indépendante du promoteur de KISS1. L'étude de ces cas permet de mieux comprendre les conséquences des mutations perte de fonction de ERalpha ainsi que les mécanismes de régulation exercés par l'oestradiol via ERalpha. Dans un second temps, je me suis intéressée à la génétique de la puberté précoce centrale (PPC) et particulièrement au gène MKRN3 (Makorin ring finger protein 3) puisqu'il s'agit de la cause génétique la plus fréquente de la PPC. MKRN3 est un gène soumis à empreinte maternel dont la fonction protéique n'est pas connue. La détermination de la pathogénicité des variants faux-sens associés à la PPC repose presque exclusivement sur les analyses in silico. Dans cette partie de mon travail, j'ai montré que les outils usuels d'analyse in silico ne sont pas performants pour déterminer la pathogénicité des variants faux-sens rares de MKRN3. J'ai également proposé une nouvelle approche pour annoter la pathogénicité des variants basée sur l'analyse de la contrainte mutationnelle de MKRN3 et la conservation des acides aminés au sein de la famille des protéines MKRN. Les PPC avec transmission maternelle représentent la majorité des PPC familiales et ne sont pas expliquées par une mutation de MKRN3. J'ai cherché à identifier de nouveaux gènes impliqués dans la PPC de transmission maternelle, en partant de l'hypothèse qu'il pourrait exister un gène majeur selon un modèle monogénique. Pour cela, j'ai sélectionné 27 patients provenant de 18 familles chez qui l'analyse d'un panel de gènes associés à la PPC n'était pas contributive. L'analyse des variants sur les régions codantes combinée à l'analyse des variations du nombre de copies (CNV) sur l'ensemble du génome m'a permis d'identifier des gènes candidats dont la fréquence a été évaluée sur une cohorte réplicative de 48 patients par séquençage à haut débit (NGS). Cette analyse n'a pas permis d'identifier un gène majeur. Toutefois, nous avons identifié des variants perte de fonction dans deux gènes pour lesquels l'analyse de l'expression hypothalamique chez la souris a montré une diminution pendant la phase juvénile, suggérant leur implication dans le contrôle post-natal de la maturation de l'axe HHG. Cette troisième partie indique que la PPC est une maladie génétique complexe. Ce travail de thèse permet de mieux comprendre les conséquences cliniques et biologiques de la perte de fonction de ERalpha. Il confirme la complexité du contrôle génétique du développement et de la maturation de l'axe HHG. Finalement, il montre que l'annotation des variants pour les maladies de la puberté est complexe et que les analyses in-silico actuelles ne sont pas adaptées à l'étude de la PPCThe development of the gonadotropic axis (HHG) begins during fetal life but is not completed until puberty. Numerous players are involved at each stage, and a defect in any one of them can lead to pubertal pathologies or fertility disorders in adulthood. Genetic factors play a central role in the development of the HHG axis, and the genetic study of pubertal pathologies has led to major advances in our understanding of the underlying molecular mechanisms, although there are still many unknowns. For my thesis work, I chose to explore the genetics of pubertal diseases in order to better understand the etiopathogenic mechanisms of these complex disorders. First, I had the opportunity to study a consanguineous family in which two sisters showed an absence of puberty associated with increased concentrations of estradiol and gonadotropins. We identified a rare homozygous variant in the estradiol receptor alpha (ERalpha). In vitro study of the mutated receptor showed a decrease of its regulatory activity on a promoter containing Estradiol Response Elements, as well as a paradoxical ligand-independent activation of the KISS1 promoter. The study of these cases provides a better understanding of the consequences of ERalpha loss-of-function mutations and the regulatory mechanisms exerted by estradiol via ERalpha. Next, I focused on the genetics of central precocious puberty (CPP), and in particular the MKRN3 (Makorin ring finger protein 3) gene, since its mutations are the most common genetic cause of CPP. MKRN3 is a maternally imprinted gene whose protein function is unknown. Determining the pathogenicity of CPP-associated missense variants relies almost exclusively on in silico analyses. In this part of my work, I have shown that the usual in silico analysis tools do not efficiently determine the pathogenicity of rare MKRN3 missense variants. I have also proposed a new approach to annotate the pathogenicity of variants based on the analysis of MKRN3 mutational constraint and amino acid conservation within the MKRN protein family. Maternally inherited CPP accounts for the majority of familial CPP and is not explained by a mutation in MKRN3. I aimed to identify new genes involved in maternally inherited CPP, based on the hypothesis that a major gene might exist in a monogenic model. For this purpose, I selected 27 patients from 18 families in whom analysis of a panel of genes associated with CPP was non-contributory. Analysis of variants in coding regions combined with genome-wide copy number variation (CNV) analysis led to the identification of candidate genes whose frequency was assessed on a replicative cohort of 48 patients by high-throughput sequencing (NGS). This analysis failed to identify a major gene. However, we did identify loss-of-function variants in two genes for which mouse hypothalamic expression analysis showed a decrease during the juvenile phase, suggesting their involvement in the post-natal control of HHG axis maturation. This study shows that CPP is a complex genetic disease. My research provides a better understanding of the clinical and biological consequences of loss of ERalpha function. It confirms the complexity of genetic control of development and maturation of the HHG axis. Finally, it shows that the annotation of variants for pubertal diseases is complex and that current in-silico analyses are not adapted to the study of CPP
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Timmons, Brian Weldon Bar-Or Oded. "Immunological changes in response to acute exercise, considering puberty and sex /". *McMaster only, 2005.
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Fallah-Rad, Amir Hooshang. "Interrelation between thyroid hormones and onset of puberty in ram lambs". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ31977.pdf.
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Takahashi, Melanie L. "Adolescence and identity transformation, a cross-cultural analysis of puberty initiations". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ36851.pdf.
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Andersson, Håkan. "Photoperiodism in pigs : studies on timing of male puberty and melatonin /". Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/v90.pdf.
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Cubitt, Tania Anne. "Environmental factors, pasture composition, growth rate and puberty in growing Thoroughbreds". Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/31576.
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A rapid growth phase often occurs with the onset of spring in the young horse. This coincides with changes in day length, temperature, and progesterone concentrations. The change in growth, from slow to rapid in young horses has been associated with various forms of developmental orthopedic disease. The objective of this study was to distinguish associations between progesterone concentrations and other physiological and environmental measures from birth through 16 mo in young Thoroughbreds. Growth data and plasma samples were collected monthly from 3 annual crops of 20 foals. Plasma progesterone (P4) and insulin like growth factor one (IGF-I) concentrations were measured with previously validated radio immunoassay's (RIA). Progesterone concentrations were compared with day length, IGF-I and ADG using Spearman correlations. Concentrations of progesterone at birth (2.3 ± 0.4 ng/mL) decreased within the first week of life to basal values (0.11 ± 0.01 ng/mL) in colts and fillies. Progesterone in the geldings remained at baseline concentrations at all sample times. An abrupt increase in progesterone concentration was detected in fillies at a mean age of 385 ± 6.4 d, weight 381 ± 7.2 kg, and ADG 0.63 ± 0.04 kg/d. Elevations in progesterone concentrations coincided with a measured day length of 13 ± 0.1 hrs, and temperature of 15 ± 1.7 °C. Positive associations were established between progesterone concentration day length (r = 0.59; P<0.0001), IGF-I (r = 0.25; P<0.01) and ADG (r = 0.34; P<0.0001). Day length IGF-I and ADG began to increase for both geldings and fillies at approximately 340 d of age, while progesterone started to increase at 385 ± 6.4 d for the fillies only. From this it could be hypothesized that an increase in ADG combined with optimal environmental conditions, may be associated with the subsequent elevation in progesterone concentrations in fillies. The relationship between IGF-I, and various reproductive hormones has been studied in the adult horse, yet the associations between environmental factors, ADG, and progesterone concentrations demonstrated in growing yearlings further emphasizes the extensive changes occurring during this crucial developmental stage.Master of Science
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Tregaskes, Lisa D. "Performance testing Simmental heifers : the effects on puberty and superovulatory response". Thesis, University of Aberdeen, 1994. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU066541.
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Genetic change in Simmental cattle is being accelerated using multiple ovulation and embryo transfer (MOET) techniques. Success of the project depends largely on the ability to generate grade 1 embryos from juvenile heifers following a performance test. Performance testing imposes specific nutritional, management and environmental conditions on heifers which may influence the onset of puberty and subsequent response to superovulation. The objectives of this study were to determine when puberty occurred in Simmental heifers on performance test and to investigate the effects of pubertal development and performance during test on superovulatory response. Heifers were performance tested between 23 and 49 weeks of age. Performance test measurements included: food intake, energy intake, liveweight, backfat depth, muscle depth and muscling score. The onset of puberty was determined in one generation of heifers (n=30) by detecting elevated plasma progesterone levels indicative of first ovulation. Following performance test heifers were superovulated, using ovine FSH, artificially inseminated and embryo recovery carried out at 52 and 61 weeks of age. Puberty occurred in 87% of heifers before the end of test. There was considerable variation in age, liveweight and withers height at puberty, however, daily liveweights gain appeared to be an important determinant of age at puberty. The yield of grade 1 embryos at the first embryo recovery was highest in prepubertal heifers, however, these heifers experienced a substantial decrease in yield at the second recovery apparently due to reduced recovery rates. Investigation of relationships between performance on test and superovulatory response in three generations of heifers (n=110) revealed no significant effect of performance during test on the yield of grade 1 embryos. It was concluded that several factors contributed to reduced embryo yields including: ineffective control of the corpus luteum in cyclic heifers; the incidence of short luteal phases in pre- and peri-pubertal heifers; luteinization of potential ovulatory follicles; and inappropriate timing of exogenous synchrony and superovulation treatments in relation to waves of follicular development.
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Spjuth, Linda. "Di(2-ethylhexyl) phthalate and semen quality in boars : effects of pre-pubertal oral exposure on sperm production, viability and function post-puberty /". Uppsala : Dept. of Clinical Sciences, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/2006104.pdf.
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Gasser, Chad Lamar. "Ovarian and endocrine dynamics associated with sexual maturation in beef heifers and the influence of diet, weaning age, and other factors during early reproductive development". Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1122295880.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xvii, 181 p. : ill. Includes bibliographical references (p. 159-181). Available online via OhioLINK's ETD Center
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Silva, Denise Salioni da [UNESP]. "Puberdade retardada no rato macho: correlações entre indicadores externos e internos e repercussões sobre a qualidade espermática e fertilidade". Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/87768.
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silva_ds_me_botib.pdf: 411709 bytes, checksum: 1274000fd98416a831be271d8963c9a7 (MD5)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...
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)
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Westling, Erika Helen. "Timing of pubertal maturation and substance use gender differences in family, peer, and individual difference factors /". Diss., Restricted to subscribing institutions, 2007. http://proquest.umi.com/pqdweb?did=1495962311&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Leppik, Aire. "Changes in anthropometry, somatotype and body composition during puberty : a longitudinal study /". Online version, 2005. http://dspace.utlib.ee/dspace/bitstream/10062/520/5/leppik.pdf.
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Martinez, Chavez Carlos Cristian. "Photic Entrainment and onset of puberty in Nile tilapia Oreochromis niloticus niloticus". Thesis, University of Stirling, 2008. http://hdl.handle.net/1893/354.
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Despite teleosts being the largest and most diverse group of vertebrates, fish models currently used to study photoperiodic effects on fish physiology have been limited to a few species, most of which are temperate seasonal breeders. The overall aim of this work was to expand our knowledge on circadian biology and environmental physiological effects in Nile tilapia (Oreochromis niloticus niloticus), a continuous breeding species of tropical-subtropical origin. The circadian light axis of Nile tilapia is described with regards to melatonin production. Circadian melatonin profiles of fish under 12L:12D photoperiods were observed to be low at day and high at night, suggesting melatonin to be an entraining signal as observed in all other vertebrates. When constant light (LL) was used, such day and night fluctuations where abolished. However when fish where exposed to constant darkness (DD) a strong robust endogenous melatonin rhythm was found, suggesting the presence of circadian oscillators in this species. Importantly, this endogenous rhythm was observed to be maintained for at least three weeks under darkness and proved to be circadian in nature. Moreover, although the melatonin system was able to produce day and night melatonin rhythms when exposed to a different (6L:6D) photocycle, the oscillator appeared to not be entrainable to such a short photo cycle when exposed to DD, as melatonin levels remained high. When comparing the circadian organization of different teleost species including Nile tilapia, preliminary studies showed at least three divergent circadian light organizations in teleosts. Nile tilapia was characterised by a pineal gland far less sensitive than in other fish species as demonstrated through in vitro studies. Furthermore, pineal melatonin production was clearly dependent on the light perceived by the eyes as ophthalmectomy resulted in basal plasma melatonin levels during the dark period. These findings are the first to be reported in a teleost and could be comparable to the circadian light organization of higher vertebrates such as mammals. The onset of puberty of Nile tilapia was studied with regards to the newly discovered Kiss1/GPR54 system. Such a system has recently been discovered in mammals and found to be the primary switch of the brain-pituitary-gonadal (BPG) axis. The results of this study not only suggest a link between the Kiss1/GPR54 system and the onset of III puberty in this tropical batch spawning teleost, that would be a highly conserved feature across vertebrates, but also that the transcriptional mechanisms regulating GPR54 expression could be directly or indirectly influenced by light. Finally, a study was conducted on the effects of different intensities of continuous light (LL) on the growth and sexual development of Nile tilapia up to first maturation. The results showed a significant growth response of fish in all LL treatments compared to control fish. Importantly, this confirmed that LL enhances growth in this species and suggests that it is the light regime more than the intensity which is having an effect. This work thus provides important basic knowledge of the light entrainment pathway and circadian melatonin rhythms in Nile tilapia. Of special importance is the discovery of a strong endogenous melatonin oscillator and a novel circadian organization in fish which would seem to be homologous to that observed in higher vertebrates. Moreover, this work provides evidence that the newly discovered Kiss1/GPR54 system has a similar role in fish as has been found in mammals and that such a system could be directly or indirectly regulated by light. If so, Nile tilapia and other fish species could become important models in the chronobiology and reproduction fields. Finally, this work not only increases our basic and applied knowledge of this species, but also broadens our understanding of the circadian light axis in teleosts and its mediatory effects on reproduction.
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Emerson, Sam R. "Changes in expiratory flow limitation during exercise from pre- to post-puberty". Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/17376.
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Master of ScienceDepartment of Kinesiology
Craig A. Harms
Expiratory flow limitation (EFL) during exercise can limit exercise tolerance. We have recently reported a high prevalence of EFL independent of sex in prepubescent children (Swain et al. 2010) that greatly exceeds that reported in adults. It is unknown how maturation and growth from pre- to post-puberty affects pulmonary function, specifically EFL, during exercise. The purpose of this longitudinal study was to investigate the changes in cardiopulmonary function from pre- to post-puberty in boys and girls. We hypothesized that EFL prevalence would decrease from pre- to post-puberty (with boys exhibiting a greater decrease than girls) and that the decrement could be explained by an increase in pulmonary function and a decrease in VE/VCO2. Twenty-one children (ages 12-16 yrs; 11 boys, 10 girls) were recruited from 40 prepubescent children who completed testing in our laboratory ~5 years ago. Subjects completed pulmonary function tests before and after an incremental exercise test to exhaustion (VO2max) on a cycle ergometer. EFL was determined using the percent tidal volume (VT) overlap method. Nineteen of the 21 subjects (10 boys, 9 girls; 90%) exhibited EFL pre-puberty, while only 7 of the 21 subjects (5 boys, 2 girls; 33%) exhibited EFL post-puberty. Of the subjects who experienced EFL post-puberty, all had experienced EFL pre-puberty. Boys had a significantly greater vital capacity (VC) than girls both pre- (~15%) and post-puberty (B: 4.73 ± 0.53; G: 3.80 ± 0.29 L). Maximal aerobic capacity (VO2max) significantly increased (~110% in girls and ~120% in boys) from pre- to post-puberty and was greater (p<0.05) in boys post-puberty (B: 2.76 ± 0.43; G: 1.94 ± 0.35 L/min). VE/VCO2 also significantly decreased (~13%) in both boys and girls. Post-puberty subjects regulated tidal breathing at higher lung volumes (greater ERV/FVC and lower IRV/FVC) during exercise compared to pre-puberty. None of the subjects experienced significant arterial desaturation pre-puberty or post-puberty. Our findings suggest that the prevalence of EFL declines as children mature from pre- to post-puberty, likely due to increases in lung size, decreases in VE/VCO2, and/or changes in breathing mechanics that are greater than increases in maximal ventilation that occur with increased pulmonary gas exchange.
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Anderson, Leslie H. "Maturation of hypothalamic centers associated with the onset of puberty in heifers /". The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu148793557377098.
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Joshi, Rupali Narayan. "IDENTIFICATION OF MECHANISMS OF DELAYED PUBERTY ON BONE STRENGTH DEFICITS DURING DEVELOPMENT". Diss., Temple University Libraries, 2010. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/55431.
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KinesiologyPh.D.
Osteoporosis which is frequently referred to as a pediatric disease with geriatric consequences (Golden, 2000) can result from a lack of optimal bone accrual during the development (NIH Consensus Development Panel on Osteoporosis Prevention, Diagnosis, and Therapy, 2001). Pubertal timing is a key factor that contributes to optimal bone accrual and strength (Bonjour et al., 1994; 21 Warren et al., 2002). Bone mass doubles during the onset of puberty and young adulthood (Katzman et al., 1991) with more than 90% of peak bone mass being accrued at the end of second decade of life (Schneider & Wade, 2000). The rate of periosteal expansion is elevated during the pubertal period (Specker et al., 1987; Bradney et al., 2000) and this expansion parallels longitudinal growth (Parfitt, 1994). Irrespective of other changes, periosteal expansion lowers fracture risk by improving the strength of long bones by increasing the moment of inertia (Orwoll, 2003). Therefore, a delay in puberty may actually increase the time available for periosteal development and positively affect bone strength. Previous animal studies have shown decreases in strength, endocortical bone formation and increases in periosteal bone formation with delayed puberty. Clinical studies report negative effects of delayed puberty on bone mass accrual suggesting that delayed puberty is a multifactorial problem affecting bone strength development. The purpose of this study was to determine the effect of delayed puberty on mechanical strength and endocortical bone marrow cells in two models: female rats treated with gonadatropin releasing hormone antagonists (GnRH-a) and energy restriction (30%). Thirty-two female Sprague Dawley rats (21 to 22 days-of-age) were received from (Charles Rivers Laboratories, Wilmington, MA, USA) and housed individually at the Temple University Central Animal Facility (Temple University Weiss Hall). Animals were randomly assigned to one of three groups; control (n=10), GnRH-a (n=10) and energy restriction (ER) (n=12). The GnRH-a group was injected with gonadotropin releasing antagonist injections (GnRH-a) (Antide, Bachem, Torrance, Ca. USA) at a dose of 2.5 mg/kg/BW. The ER group received a 30% energy restricted diet (0pen Source diet (D07100606)(Research Diets, New Brunswick, NJ). All animals were sacrificed on Day 51. One way analysis of variance testing (ANOVA) with a significance level of 0.05 was used to assess group differences. Following the two protocols the uterine weight in the GnRH-a group was 80.6% lower than control; no change in the ER group. Ovarian weight was significantly lower in the GnRH-a group (83.3%) and in the ER group (33.3%) as compared to controls. A 22.7% lower muscle weight was found in the ER group but was equal to control and GnRH-a when normalized by body weight (BW). The retro-peritoneal fat pad weight was significantly decreased by 64.95% in the ER group as compared to controls. Energy restriction did not result in any deficit in bone strength when normalized by body weight however the GnRH-a group had a 26.2% lower bone strength compared to control. Histomorphometric changes were not significantly different between groups, but the ratio for periosteal versus endocortical bone formation rates for the control group was 1.38, GnRH-a was significantly higher with a ratio of 5.54 and for ER was 3.02 indicating that periosteal BFR are almost twice endocortical BFR in the experimental groups. There was a significant decrease in the trabecular percent bone volume (BV/TV) of the lumbar vertebra in the GnRH-a group (20.2%) compared to control. However BV/TV was significantly higher in the ER (18.4%) compared to the control group. Proliferation was suppressed to 59.6% of control in the GnRH-a group but only 85.5% of control in the ER group. The alkaline phosphatase activity was 31.2% lower in the GnRH-a group and 63.9% lower in the ER group. The relative quantification (RQ) of RUNX2 gene expression was lowest in control followed by GnRH-a and highest in ER group although no statistical significance was observed between any groups. Thus our data infers that 30% energy restriction does not negatively impact bone health. Thirty percent food restriction with no deficits in micronutrients or hormone suppression may just suppress growth as indicated by the maintenance of bone strength per body weight and equivalent muscle mass per body weight in the ER group compared to control. The GnRH-a injections resulted in decreased bone strength and trabecular bone volume. Female Athlete Triad or Anorexia Nervosa are the two clinical conditions hypothesized to result from a combination of ER and estrogen deficient environment. Studies replacing estrogen in hypothalamic amenorrhea or IGF-1 in anorexia alone have failed to improve bone mineral density (BMD), but a combination of IGF-1 and estrogen has been successful in improving BMD. This suggests that estrogen dependant and independent mechanisms work in combination to protect bone. Our study investigated both mechanisms separately and indicates that ER at 30% may be protective for bone health. Since estrogen deficiency may be the extreme end of the spectrum affecting trabecular bone, treatment therapies may have to be based on age, magnitude and severity of energy restriction and presence or absence of menstrual status.
Temple University--Theses
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Seigenfuse, Matthew David. "Low Estrogen Model and Percent Lamellar Bone Pre and Post Puberty [thesis]". Master's thesis, Temple University Libraries, 2010. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/94126.
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KinesiologyM.S.
INTRODUCTION: Pubertal growth is an important time during development for bone accrual and attainment of peak bone mass. Suboptimal bone gain has been observed in females with reproductive abnormalities such as primary and secondary amenorrhea and these conditions are very prevalent in female athletes. Amenorrhea is associated with decreased estradiol levels. Previous research has shown that in prepubertal animals a low estrogen environment significantly decreased mechanical strength, but there was no significant loss in bone area and actually an increase in moment of inertia. The decrease in mechanical properties may be related to the microstructure of the bone. Two types of bone are involved in growth-- woven bone, which is added for structural support in the short term, and lamellar bone , which is highly organized and has a greater contribution to overall strength. We will test the hypotheses that suppressed estradiol will result in bones with no change in cortical area and decreased strength properties but will have a larger composition of non lamellar bone as opposed to lamellar bone. PURPOSE: The goal of this study was to determine the relative amounts of woven and lamellar tissue in a bone and the relationship with the bone's mechanical strength in two models of low estrogen-- pre- and post-pubertal onset. METHODS: Fifty-Five female Sprague-Dawley rats were randomly assigned into four groups: a control group (n=14) and three experimental groups injected with gonadotropin releasing-hormone antagonist (GnRH-a)-- the Dose 1 group was injected with 1.25 mg/kg/dose daily (n=14), the Dose 2 was injected with 2.5 mg/kg/dose daily (n=14), and the Dose 3 group was injected with 5.0 mg/kg/dose, 5 days per week (n=13). All groups were sacrificed at Day 49. Additionally, twenty-nine Sprague Dawley rats were randomly assigned into three groups. The baseline day 65 group (BL 65) was sacrificed on day 65 (n=9). There was an aged match control group that was sacrificed on day 90 (n=12). Finally, there was an AMEN experiment group injected with 2.5 mg/kg/dose daily that was sacrificed on day 90 (n=9). All experimental groups for both protocols received injections of gonadotropin releasing hormone antagonists (GnRH-a) (Zentaris GmbH) intraperitoneally. Left femora were mechanically tested under 3-point bending. The right femora were dehydrated, embedded in polymethylmethacrylate, cut and ground to 100 µm thickness. Bones were analyzed under polarized light using Stereo Investigator Software (MBF Bioscience, VT). The proportion of the cortex with primary lamellar vs. non-lamellar/other primary tissue type was measured and expressed as percent of the total cortical bone area. Outcome measures included lamellar endocortical area, lamellar periosteal area, cortical area, endocortical area, % lamellar area and % non-lamellar area. RESULTS: There was a significant decrease (p<.05) in the distribution of lamellar versus non-lamellar cortical tissue type in the experimental group in the model of delayed puberty. Additionally, the pre-pubertal bones had a lower percentage of lamellar periosteal and endocortical area. The post-pubertal group showed no significant differences between the control and experimental group in any of the outcome measures. CONCLUSION: There were significant differences in relative bone distribution throughout the femoral cortex. Relative decreases in lamellar tissue distribution, especially on the periosteal surface, will result in decreased mechanical strength due to increased percentage of woven bone in pre-pubertal models.
Temple University--Theses
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Murray, Emma. "Immune Challenge During Puberty: Role of the Gut Microbiota and Neurobehavioural Outcomes". Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40467.
Texto completoResumen
Puberty is a critical period of development characterized by rapid physiological changes and significant brain reorganizing and remodeling. These rapid changes render the developing brain particularly vulnerable to stress and immune challenge. In mice, exposure to an immune challenge (lipopolysaccharide; LPS) during puberty causes enduring effects on stress reactivity, cognitive functioning, and depression- and anxiety-like behaviors later in life. However, the mechanisms underlying these effects are unknown. The gut microbiome can profoundly influence the immune system. There is also close bidirectional communication between the gut microbiome and the central nervous system (CNS) through neural, endocrine and immune signaling pathways, which can alter brain chemistry and emotional behaviour. Thus, we hypothesized that altering microbial composition during puberty could mitigate acute immune responses and prevent enduring outcomes later in life. The current thesis examined the effect of gut manipulation with probiotics during puberty on LPS-induced immune responses and enduring anxiety- and depression-like behaviours, and stress-reactivity in adulthood, in male and female CD1 mice (Article 1). Next, we examined age and sex differences in gut microbial composition before and after exposure to an immune challenge. We also examined the effects of consuming a single strain probiotic bacterium (Lactobacillus Reuteri) during puberty on the immune response and the long-term changes in memory, anxiety-like behavior, and stress reactivity in adulthood (Article 2). Lastly, we examined how microbial colonization between pubertal and adult mice can alter acute peripheral and central inflammatory responses to LPS (Article 3). The current dissertation has addressed sex-specific vulnerabilities to an immune challenge during pubertal development and the moderating influence of the gut microbiome. These studies have demonstrated that manipulating the gut microbiome during puberty can mitigate acute immune responses and prevent enduring neurobehavioural outcomes later in life.
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Mechaly, Alejandro S. "Neuroendocrine control of puberty in vertebrates : characteriization of the kisspeptin system in flatfish". Doctoral thesis, Universitat Pompeu Fabra, 2011. http://hdl.handle.net/10803/38523.
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The recently discovered decapeptide kisspeptin and its G-protein coupled receptor
form a signaling system expressed ubiquitously and are implicated in a variety of still
poorly characterized functions. In the brain, kisspeptin is secreted by specific
neurons and its receptor is localized in GnRH neurons. Kisspeptin signaling has
been fully established in the control of the onset of puberty in vertebrates, from fish to
mammals. In this study, we characterized the kisspeptin gene in the Senegalese sole
and characterized the kisspeptin receptor genes in both the Senegalese sole and in
the Atlantic halibut. In contrast to other fish species, the two species analyzed here
showed only the presence of one ligand and one receptor, probably as a
consequence of the genome reduction characteristic of Pleuronectiformes. However,
in both cases we found an alternative splicing mechanism based on intron retention
that produces also non-functional isoforms, but whether this is part of a mechanism
to control abundance of the active gene product is still not known. We document
spatial and temporal changes of expression of kisspeptin and its receptor in the
brain, pituitary and gonads related to the annual reproductive cycle. Finally, we
present the first evidence of a possible link between energy balance and
reproduction mediated by kisspeptin signaling in a non-mammalian vertebrate.El recentment descobert decapèptid kisspeptina i el seu receptor associat a una proteïna G formen un sistema que s’expressa ubiqüitament i que està implicat en diverses funcions, moltes de les quals encara no estan ben caracteritzades. En el cervell, la kisspeptina és secretada per neurones específiques, mentre que el seu receptor es troba a les neurones GnRH. Aquest sistema s’ha relacionat amb el control de l’inici de la pubertat en diferents vertebrats, des de peixos fins a mamífers. En aquest estudi, hem caracteritzat el gen de la kisspeptina en el llenguado senegalès, i els gens del receptor de la kisspeptina tant a llenguado senegalès com en l’Halibut de l’Atlàntic. Al contrari del que ocorre en moltes altres espècies de peixos, aquestes dues espècies només presenten un gen pel lligand i un gen pel recep- tor. Aquest fet és probable que estigui relacionat amb la reducció de la mida del genoma que han sofert els Pleuronectiformes. Tot i així, en les dues espècies s’hi troba un mecanisme d’empalmament alternatiu conseqüència d’una retenció intrónica que produeix una isoforma no funcional. Ara bé, si aquest mecanisme està relacionat amb el control de l’abundància dels trànscrits de la isoforma funcional encara està per esbrinar. Per altra banda, hem trobat canvis en l’expressió gènica tant en l’espai com en el temps durant un cicle reproductiu dels gens de la kisspeptina i el seu receptor en el cervell, pituïtària i gònades. Finalment, també presentem la primera evidència, en un vertebrat no mamífer, d’una possible relació entre el balanç energètic i la reproducció controlada pel sistema kisspeptina.
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Al-Khamees, Sami A. "Photoperiod effects on circadian rhythms and puberty onset in African catfish Clarias gariepinus". Thesis, University of Stirling, 2009. http://hdl.handle.net/1893/1819.
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Photoperiod manipulation is routinely used in the aquaculture industry with the aim to enhance growth by manipulating the timing of reproduction in several commercially important temperate fish species. However, there are clear gaps in our understanding of how photoperiod is perceived by the circadian axis and transmitted to the brain to alter reproduction. Furthermore, due to the wide range of environments inhabited by fish, it is unlikely that one single organization exists. It is therefore believed that comparative studies of temperate species “models” with tropical species such as the African catfish (Clarias gariepinus) that adapted to different environments characterized by weaker light signals can help in such an aim. A number of studies were therefore performed in this PhD project to expand our knowledge on circadian biology and environmental physiological effects in African catfish. The first aim was to characterize the circadian melatonin system in this species (chapter 3). Results clearly showed that the control of melatonin production by the pineal gland was very different in the African catfish as compared to temperate species such as salmon and trout. Indeed, melatonin production appeared to mainly depend on light stimuli perceived by the eyes as opposed to salmonids where light directly perceived by the pineal gland regulates its own melatonin production within photoreceptors. The main evidence was obtained in ophthalmectomised fish that were unable to synthesize and release melatonin into the blood circulation during the dark period. This was the first time that such a decentralized organisation, similar in a way to the mammalian system, was found in any teleost species. In vitro results also supported such findings as African catfish pineal glands in isolation were not able to normally produce melatonin at night as usually seen in all other fish species studied so far. This indirectly suggested that pineal gland photo-sensitivity might be different in this tropical species. Further studies were performed to better determine the amount of light that can be perceived by the African catfish pineal gland depending on light transmittance though the skull (where the pineal gland is located). Surprisingly, it appeared that catfish cranium act as a stronger light filter than in other species resulting in lower light irradiance of the pineal gland. This could explain, although it still needs to be further confirmed, why African catfish photic control of melatonin produced by the pineal would have evolved differently than in temperate species. The work then focused on better characterizing diel melatonin production and endogenous entrainment through exposure to continuous photic regimes (continuous light, LL or darkness, DD) (chapter 4). Daily melatonin profiles of fish exposed to 12L:12D photoperiod (routinely used in indoor systems) confirmed low melatonin production at day (<10 pg/ml) and increase at night (50 pg/ml) as reported in most vertebrate species studied to date. Interestingly, results also showed that melatonin production or suppression can anticipate the change from night to day with basal melatonin levels observed 45 mins prior to the switch on of the light. These observations clearly suggest the involvement of a clock-controlled system of melatonin secretion that is capable of anticipating the next photophase period. Furthermore, when constant light (LL) was applied, day/night melatonin rhythms were abolished as expected due to the constant photic inhibition of AANAT activity (e.g. one of the enzyme responsible for the conversion of serotonin into melatonin). However when fish were exposed to constant darkness (DD), a strong endogenous melatonin rhythm (maintained for at least 4 days and 18 days in catfish and Nile tilapia respectively) was found, demonstrating once again the presence of robust circadian oscillators in this species. The next aim of the doctoral project was then to investigate circadian behaviour of catfish through locomotor activity studies (Chapter 5). African catfish is again a very interesting “model” due to its reported nocturnal activity rhythmicity as compared to most other teleosts species. Locomotor activity is considered as a very useful tool to elucidate the mechanisms of circadian organization in both invertebrates and vertebrates circadian. Results first confirmed the nocturnal activity rhythms in the species. Furthermore, clear circadian endogenous rhythms were observed under constant light (LL) or darkness (DD) during several days before losing rhythmicity. Interestingly, the activity levels varied depending on the stocking density. Finally, the last aim of this project was to test the effects of a range of photoperiodic manipulations on growth performances, sexual development and reproductive performances in African catfish reared from eggs to puberty. Results did not show any differences at the early sages (up to 90 days post hatching) in growth performances nor mortality (high) between control 12L:12D and LL treatments. In contrast, during the juvenile-adult period (from 120 to 360 DPH), significant growth effects were observed, as previously reported in other catfish species, with fish under LL displaying lower growth rate, food consumption and feed conversion efficiency in comparison to most other treatments (12:12, LL, 6:6, 6:18, 12-LL and LL-12) especially 12l:12D. However, no major effects of the photoperiodic treatments were observed with all fish recruited into puberty and developing gonads although differences in the timing of gametogenesis could be observed, especially a delay (circa 2 months) in females exposed to short daylength (6L:18D and 6L:6D). As for egg quality, egg diameter was the only parameter to differ between treatments (slightly larger in egg batch from LL treated females). Overall, none of the photoperiodic regime suppressed maturation in African catfish as opposed to some temperate species. The work carried out during this PhD project clearly advanced our understanding of circadian rhythmicity, light perception and effects of photoperiod on physiology in a tropical species. Future studies are now required to further characterise the circadian system and link it to evolutionary trends within vertebrates.
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Chandarana, N. y N. K. Bogutska. "Gender-specific peculiarities of the bronchial asthma phenotypes in children after puberty onset". Thesis, .Матеріали ІV Міжнародного медико-фармацевтичного конгресу студентів і молодих учених [«Пріоритети і перспективи молодіжної науки»] BIMCO, 2017. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/13164.
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Mohamed, Abdullahi Abdulkadir y N. K. Bogutska. "Transition of the bronchial asthma phenotypes in females from pre- to post-puberty". Thesis, Матеріали ІV Міжнародного медико-фармацевтичного конгресу студентів і молодих учених [«Пріоритети і перспективи молодіжної науки»] BIMCO, 2017. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/13170.
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Nirbhay, Chandarana y N. K. Bogutska. "Gender-specific differences in children with bronchial asthma before and after puberty onset". Thesis, Fundamental Science and Clinical Medicine: Abstract Book of 20th International Medical Biological Conference of Young Researchers. St. Petersburg, 2017, 2017. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/13186.
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