Search results for "puberty"
showing 10 items of 82 documents
Treatment of cryptorchidism with a potent analog of gonadotropin-releasing hormone.
1978
Pernasal therapy of cryptorchidism with D-Leu6-des-Gly10-gonadotropin-releasing hormone ethylamide (D-Leu6-des-Gly10-GnRH-EA), a potent, long-acting GnRH analog, was attempted. Eleven prepubertal cryptorchid boys received between 25 microgram once daily and 25 to 50 microgram twice daily for 5 to 12 weeks. Complete testicular descent was achieved in 4 of the 11 boys. GnRH tests (1.5 microgram/kg intravenously), conducted in six boys before treatment, after 4 weeks of treatment, and in 2 boys 3 months after treatment, did not reveal changes in gonadotropin secretion indicative of precocious puberty or of decreased hypophyseal sensitivity to GnRH. Antibodies to the GnRH analog or to GnRH coul…
Vitamin D, parathyroid hormone, and bone mass in adolescents.
2005
This article provides a review of the evidence identifying the factors related to vitamin D status in adolescents. The prevalence of vitamin D deficiency based on 25-hydroxyvitamin D [25(OH)D] of <25 nmol/L ranges from 0 to 32% depending on the season measured and the latitude of the population assessed. The factors that have been reported to affect serum 25(OH)D in adolescents include ethnicity, gender, puberty stage, parathyroid hormone (PTH), dietary vitamin D intake, and sun exposure. Vitamin D supplementation studies are limited to small populations and with supplementation focused on winter months when sunlight may be inadequate. The effects of vitamin D status and supplementation on …
Preliminary Findings: 25(OH)D Levels and PTH Are Indicators of Rapid Bone Accrual in Pubertal Children
2007
The objective of this study was to evaluate the role of serum levels of 25(OH)D and PTH on the accumulation of whole body bone mass in a cohort of children.This was a longitudinal study (1.98 +/- 0.07 y) of sixty-nine children (89% Caucasian, 44% male) enrolled in a calcium supplementation trial. Bone area, bone mineral content (BMC) and density (BMD) of the whole body and radius were assessed using a QDR 2000 (Hologic, Inc) dual energy x-ray absorptiometer. Serum PTH and 25(OH)D were measured using radioimmunoassays.Vitamin D stores were inversely related gain in bone area (p0.002), BMC (p0.002) BMD (p0.027), as well as to PTH levels (p0.0001). Compared to those with adequate vitamin D sto…
Neuromuscular function and balance of prepubertal and pubertal blind and sighted boys
2006
Aim: To compare the neuromuscular function and balance of blind prepuberty- and puberty-aged boys to those with normal sight. Methods: Thirty-three prepubertal (aged 9–13 y) and pubertal (aged 15–18 y) blind and sighted boys were tested for muscle mass thickness, electromyography and maximal isometric strength, dynamic explosive actions, and balance. Results: There was no difference in the muscle mass thickness, maximal strength or vertical jump between the blind and sighted boys. However, fitness-ball throwing and five-jump distances were significantly shorter in both blind groups compared to the sighted groups. One-leg stance of the prepuberty-aged sighted boys was 109 (67) s and in blind…
Chernobyl exposure as stressor during pregnancy and hormone levels in adolescent offspring
2008
Background: Animal research suggests a programming effect of prenatal stress in the fetal period, resulting in disruptions in behavioural and neuromotor development. Physiological changes that mediate these effects include alterations in the hypothalamic-pituitary-adrenal axis and in testosterone levels. This human study focuses on changes related to these physiological systems after prenatal stress exposure. Methods: We examined the potential effect of prenatal stress associated with the Chernobyl disaster in an ongoing genetic epidemiological study in Finland. One birth cohort of twins (n = 121 twin pairs) was exposed in utero to maternal stress, and their saliva cortisol and testosterone…
Genetic and environmental influences on pubertal timing assessed by height growth
2008
Secular trends towards earlier puberty, possibly caused by new environmental triggers, provide a basis for periodic evaluation of the influence and interaction of genetic and environmental effects on pubertal timing. In such studies, a practical marker that reflects timing of puberty in both genders needs to be used. We investigated genetic and environmental influences on pubertal timing by using change in the relative height between early and late adolescence (HD:SDS, height difference in standard deviations) as a new marker of pubertal timing. HD:SDS correlated well with age at peak height velocity in a population of men and women with longitudinal growth data. In 2,309 twin girls and 1,8…
Prolactin secretion before, during, and after chronic gonadotropin-releasing hormone agonist treatments in children.
2005
Objective To examine the effect of long-term administration of GnRH agonists (GnRHa) on PRL secretion in children affected by central precocious puberty (CPP) and growth hormone deficiency (GHD). Design Prospective analysis of blood sampling before, during, and after GnRHa treatments. Setting Pediatric endocrine center. Patient(s) One hundred nineteen and 93 children with a diagnosis of CPP and GHD, respectively. Intervention(s) Monthly depot injections of GnRHa drugs (leuprorelin acetate 3.75 mg [LA] and triptorelin 3.75 mg [TR]) administered to CPP and GHD patients for 40 and 24 months, respectively. Main Outcome Measure(s) Serum PRL levels at baseline and after 6, 12, 18, 24, 30, 36, and…
Analysis of the Relationship between Tobacco Smoking and Physical Activity in Adolescence: A Gender Specific Study
2021
Background and Objective: Although smoking and the physical activity level (PAL) are important determinants of health status in adolescence, there is a lack of information on the relationship between smoking and PAL in early adolescence. The objective of this study was to evaluate the gender-specific relationship between smoking and PAL in 14-to-16-year-old adolescents. Materials and Methods: The sample included 650 adolescents (337 girls, 14.7 ± 0.5 years at first testing wave) from Bosnia and Herzegovina. During the first testing wave, participants were tested using structured questionnaires. Second testing was commenced after approximately 20 months (16.4 ± 0.6 years). The variables were…
Toward Prevention of Doping in Youth Sport: Cross-Sectional Analysis of Correlates of Doping Tendency in Swimming.
2019
Doping is recognized as one of the most important problems in sports, but a limited number of studies have investigated doping problems in youth athletes. This study aimed to evaluate doping tendency (potential doping behavior (PDB)) and correlates of PDB in youth age swimmers. The participants were 241 competitive swimmers (131 females
Exploring the Association between Alcohol Drinking and Physical Activity in Adolescence; Two-Year Prospective Study in Younger Adolescents from Bosni…
2021
Insufficient physical activity and alcohol consumption (AC) are important health-threatening behaviors in adolescence, but there are controversial findings regarding the association that may exist between AC and physical activity levels (PALs) at this age. This study aimed to prospectively examine the relationship that may exist between AC and PAL in younger adolescence, considering the potential confounding effect of sports participation. The participants (n = 669, 337 females) were adolescents from Bosnia and Herzegovina who were tested on two occasions, at baseline (14 years of age) and again at follow-up (16 years of age). The variables included AC (as indicated by the AUDIT questionnai…