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PubMedDate not supplied

Caregiver understanding of adolescent development in residential treatment.

PROBLEM: Caretaker knowledge and understanding of adolescent development and its application to clinical practice with severely emotionally disturbed adolescents in residential treatment. METHODS: Twenty child-care workers and registered nurses participated in semistructured interviews analyzed using dimensional analysis, a grounded theory method. FINDINGS: Three distinct categories of caregivers were identified based on level of expertise and engagement in developmentally appropriate treatment practices: inexperienced, party-liners, and transcenders. Developmental issues identified included lack of resident preparation for puberty and staff discomfort with adolescent sexuality. CONCLUSIONS: Caregiver, institutional, and social barriers to developmentally sensitive practice were identified. Practice recommendations include direct preparation of children and adolescents in residential treatment for pubertal changes and sexual development, and careful discernment of age-appropriate and psychopathological adolescent behaviors.

Adolescent↗
PubMed2000

Cranial irradiation of female rats causes dose-dependent and age-dependent activation or inhibition of pubertal development.

Cranial irradiation in prepubertal children with leukemia or brain tumors can lead to precocious or in high doses to late puberty. To unravel the underlying mechanisms, we developed a rat model with selective cranial Co60-irradiation technique. Infantile (12-16 d old) or juvenile (21-23 d old) female Sprague-Dawley rats received a single dose of 4, 5, 6, 9 or 2 x 9 Gy (at days 21 and 23). Each group consisted of 7-20 animals. High radiation doses (9 Gy and more) caused retardation of sexual development, whereas low radiation doses (5 or 6 Gy) led to accelerated onset of puberty in 20% of infantile irradiated rats animals as determined by vaginal opening. Interestingly, at peripubertal age (postnatal day 32-34), 5 or 6 Gy infantile irradiated rats had significantly higher serum LH levels stimulated by GnRH and estradiol levels (p < 0.05). 2 x 9 Gy irradiated rats had at the age of 3 mo a marked growth retardation and significantly lower GH levels than the controls (p < 0.05) whereas prolactin, FSH, TSH, T4, and corticosterone levels were comparable with controls. These studies demonstrate that the GnRH-pulse generator is very radiosensitive as precocious activation occurred after low dose irradiation (5 or 6 Gy) of infantile rats without any other endocrine disorder. High radiation doses (9 or 2 x 9 Gy) induced retardation of sexual maturation and later on growth hormone deficiency. Moreover this model of cranial irradiation seems to be suitable to study the molecular mechanisms of radiation induced pubertal changes.

Age Factors↗
PubMed2005

A NIMA-related protein kinase is essential for completion of the sexual cycle of malaria parasites.

The molecular mechanisms regulating the sexual development of malaria parasites from gametocytes to oocysts in their mosquito vector are still largely unexplored. In other eukaryotes, NIMA-related kinases (Neks) regulate cell cycle progression and have been implicated in the regulation of meiosis. Here, we demonstrate that Nek-4, a new Plasmodium member of the Nek family, is essential for completion of the sexual cycle of the parasite. Recombinant Plasmodium falciparum Nek-4 possesses protein kinase activity and displays substrate preferences similar to those of other Neks. Nek-4 is highly expressed in gametocytes, yet disruption of the nek-4 gene in the rodent malaria parasite P. berghei has no effect on gamete formation and subsequent fertilization. However, further differentiation of zygotes into ookinetes is abolished. Measurements of nuclear DNA content indicate that zygotes lacking Nek-4 fail to undergo the genome replication to the tetraploid level that precedes meiosis. Cell cycle progression in the zygote is identified as a likely precondition for its morphological transition to the ookinete and for the successful establishment of a malaria infection in the mosquito.

Amino Acid Sequence↗
PubMed1984

Chronic treatment with [D-Ala6, des Gly-NH2(10)]-LHRH ethylamide reversibly delays puberty in the female rat.

Luteinizing hormone-releasing hormone (LHRH) agonist analogs have been suggested as a useful treatment for precocious puberty, though there is some concern that long-term treatment might be deleterious to normal sexual development. We have taken advantage of the very short maturation period of the female rat (approximately 35 days from birth) to examine the effects of chronic (daily) treatment with [D-Ala6, des Gly-NH2(10)]-LHRH ethylamide. We have observed that this treatment (either 1 or 2 micrograms/day) from day 5 after birth significantly delays sexual maturation but does not affect subsequent sexual cycles.

Animals↗
PubMed1995

Androgen receptor: an overview.

The action of androgens in regulating development and growth is mediated by androgen receptor (AR). AR is a member of the steroid hormone receptor superfamily, a class of receptors that function through their ability to regulate the transcription of specific genes. The AR is located in various target tissues, with its levels and activity altered with the onset of various cellular events (e.g., sexual development, malignant transformation). The modulation of AR levels occurs through a number of mechanisms, including transcription, and is regulated by various factors (e.g., androgens). The ability of AR to modulate gene transcription is through its interaction with specific DNA sequences located near or within the target gene promoter. The importance of the AR in reproductive physiology has been emphasized by the finding of AR mutations, leading to a variety of disorders, including testicular feminization syndrome. In this article, we review the structure and function of AR and the role AR plays in the function of the mammalian system.

Animals↗
PubMed2006

Multiple molecular effect pathways of an environmental oestrogen in fish.

Complex interrelationships in the signalling of oestrogenic effects mean that environmental oestrogens present in the aquatic environment have the potential to disrupt physiological function in fish in a more complex manner than portrayed in the present literature. Taking a broader approach to investigate the possible effect pathways and the likely consequences of environmental oestrogen exposure in fish, the effects of 17beta-oestradiol (E(2)) were studied on the expression of a suite of genes which interact to mediate growth, development and thyroid and interrenal function (growth hormone GH (gh), GH receptor (ghr ), insulin-like growth factor (IGF-I) (igf1), IGF-I receptor (igf1r ), thyroid hormone receptors-alpha (thra) and -beta (thrb) and glucocorticoid receptor (gr )) together with the expression analyses of sex-steroid receptors and ten other genes centrally involved in sexual development and reproduction in fathead minnow (fhm; Pimephales promelas). Exposure of adult fhm to 35 ng E(2)/l for 14 days induced classic oestrogen biomarker responses (hepatic oestrogen receptor 1 and plasma vitellogenin), and impacted on the reproductive axis, feminising "male" steroidogenic enzyme expression profiles and suppressing genes involved in testis differentiation. However, E(2) also triggered a cascade of responses for gh, ghr, igf1, igf1r, thra, thrb and gr in the pituitary, brain, liver, gonad and gill, with potential consequences for the functioning of many physiological processes, not just reproduction. Molecular responses to E(2) were complex, with most genes showing differential responses between tissues and sexes. For example, igf1 expression increased in brain but decreased in gill on exposure to E(2), and responded in an opposite way in males compared with females in liver, gonad and pituitary. These findings demonstrate the importance of developing a deeper understanding of the endocrine interactions for unravelling the mechanisms of environmental oestrogen action and predicting the likely health consequences.

Animals↗
PubMed1994

Region-specific regulation of transforming growth factor alpha (TGF alpha) gene expression in astrocytes of the neuroendocrine brain.

Certain glial cells of the hypothalamus have been implicated in the neuroendocrine control of reproductive development. Hypothalamic astrocytes appear to exert this function via a cell-cell interactive mechanism that involves the production of transforming growth factor alpha (TGF alpha), a polypeptide able to affect both glial and neuronal functions in the CNS. In the hypothalamus, TGF alpha stimulates neuronal secretion of luteinizing hormone-releasing hormone (LHRH), the neuropeptide controlling sexual development, via activation of epidermal growth factor receptors (EGFR). Since astrocytes but not LHRH neurons express EGFR, it has been postulated that the stimulatory effect of TGF alpha on LHRH release is not exerted directly on LHRH neurons, but rather via glial intermediacy. The present experiments were undertaken to define whether TGF alpha is able to exert paracrine/autocrine effects on isolated hypothalamic astrocytes, and to determine if estradiol-previously shown to increase TGF alpha mRNA levels in the hypothalamus of immature animals--can act directly on hypothalamic astrocytes to upregulate TGF alpha gene expression. Treatment with either TGF alpha or its structural homolog, epidermal growth factor (EGF), increased TGF alpha mRNA levels within 8 hr of exposure; the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) was similarly effective. Blockade of EGFR with either tyrphostin RG-50864, an inhibitor of tyrosine kinase activity, or a monoclonal antibody that prevents ligand binding abolished the upregulatory effect of TGF alpha on TGF alpha mRNA levels. In contrast to hypothalamic astrocytes, cerebellar astrocytes did not respond to either TGF alpha or EGF with changes in TGF alpha mRNA abundance.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2000

Integrated sexual healthcare: the development and review of one model of service delivery.

Sexual health is topical with many factors impacting upon its concept and hence provision. In 1995 the Sexual Health Service in East Berkshire was formed by the integration of the clinical services of Family Planning, Genitourinary and HIV Medicine with Sexual Health Promotion. The philosophy of the service is to provide holistic sexual healthcare in one visit, on one site by one clinical team. This article outlines the practical developments and the strengths and weaknesses of this model of service.

Delivery of Health Care, Integrated↗
PubMed2025

Degradation of ribosomal RNA during Plasmodium falciparum gametocytogenesis.

The life cycle of Plasmodium falciparum is characterized by complex regulatory changes that allow adaptation of the parasites to different environmental conditions, which are especially pronounced during transmission between the mammalian host and the insect vector. Previous studies have shown that P. falciparum uses three types of ribosomal RNAs (rRNA A, S1, and S2 types) at different stages of its life cycle. We used Oxford Nanopore Technologies direct RNA sequencing to investigate the dynamics of rRNA usage throughout the parasite's intraerythrocytic development, as well as in salivary gland sporozoites. Our study revealed a preponderance of A-type rRNAs during the intraerythrocytic cycle and gametocytogenesis, while S-type rRNAs slowly increase in abundance in mosquito stages starting 3 days post-infection. Salivary gland sporozoites showed an even proportion of all rRNA types. By examining the length distributions of rRNA molecules, we detected an extensive and specific degradation of rRNAs during gametocytogenesis, starting in stage II gametocytes and continuing until the final stages of gametocyte development. We hypothesize that rRNA degradation may be linked to the global translational repression and metabolic quiescence described in stage V gametocytes, similar to mechanisms observed in bacterial and eukaryotic stress responses.IMPORTANCEOur study uses Oxford Nanopore direct RNA sequencing of tightly synchronized blood-stage Plasmodium falciparum parasites to investigate the expression of ribosomal RNAs during asexual and sexual development. P. falciparum utilizes distinct types of rRNA during its development. However, due to the challenges of differentiating these highly similar molecules, their regulation and the mechanism underlying the switch between rRNA types remain unclear. We observe significant rRNA degradation in mature gametocytes, leading us to propose that this potentially leads to a reduced number of functional ribosomes when parasites become quiescent and translation is repressed.

Plasmodium falciparum↗
PubMed2003

[Sexuality in Down syndrome individuals].

OBJECTIVE: To evaluate parents and health professionals' opinions on the sexuality of Down syndrome individuals and to describe how these individuals see their own sexuality. METHODS: Both quantitative and qualitative analyses have been applied in the study. A total of 809 questionnaires were to parents and health professionals (348). Twelve focal groups' sessions were carried out separately with parents, professionals and DS individuals. Chi-square test was performed in the analysis. RESULTS: Parents see their children as eternal kids as they are afraid of the utmost outcome of their children's sexual life: unwanted pregnancy, and risk of syndrome recurrence. Health professionals revealed to be unprepared to provide sexual advice for DS individuals and adequate parents' attitude to their children's sexual drive. CONCLUSIONS: Down syndrome sexuality develops similarly to other individuals, but DS individuals experience restrictions depending on their social context.

Adult↗
PubMed2000

Influence of streptozotocin-induced diabetes and insulin treatment on the pituitary-testicular axis during sexual maturation in rats.

Effects of streptozotocin (STZ)-diabetes and insulin treatment on the functioning of pituitary-testicular axis during sexual maturation was studied. Prepubertal (30 days old) and pubertal (50 days old) male Wistar rats were made diabetic by a single injection of STZ. A group of diabetic rats was given insulin (3U/100 g b.wt./day in 2 equally divided doses), 3 days after STZ treatment. Prepubertal and pubertal rats of all groups were killed on postnatal days 51 and 71, respectively. STZ-diabetes caused marked reduction in serum LH, FSH, prolactin, testosterone and testicular interstitial fluid testosterone as well as the activities of Leydig cellular steroidogenic enzymes (3beta-and 17beta-hydroxysteroid dehydrogenases). Insulin treatment to diabetic rats maintained these changes at control range except FSH and prolactin in prepubertal rats. The results indicate that (i) diabetes-induced steroidogenic lesions in Leydig cells represent a direct consequence of dysfunctioning of pituitary-testicular axis, (ii) the adverse effects of diabetes on pituitary-testicular functions are influenced by age of its induction and (iii) optimum insulin level is essential for the acquisition of Leydig cellular steroidogenic efficacy during sexual development.

17-Hydroxysteroid Dehydrogenases↗
PubMed2003

The rape of boys and the impact of sexually predatory environments: review and case reports.

This paper describes the effect of rape and the impact of sexually predatory environments on young boys and the resulting sequelae in adulthood. It presents the literature and the case histories of Jeff and Todd to illustrate the psychic devastation that occurs, and the ensuing attempts at reestablishing boundaries and regaining a sense of autonomy and male identity. Issues including facing powerlessness, betrayal by trusted adults, and the effect of emasculation on developing sexual identity are explored. A study of almost 4,000 siblings by Nelson et al. (2002) showed that a twin who was not sexually abused himself but who grew up in the same milieu as his sexually abused twin, suffered similar psychopathologic symptoms, such as suicide attempts, alcohol dependence, and social anxiety. Todd spent his formative years in a Catholic boarding school where boys were physically and sexually abused by priests. His history illustrates the severe psychological damage this causes and is consistent with the findings of Nelson's study.

Adult↗
PubMed1992

Tamoxifen advances puberty in the White Leghorn hen.

1. Tamoxifen (TAM) administration advances puberty in cockerels. In the present study the effect of TAM administration on the sexual development of White Leghorn hens was studied. 2. Two-week-old White Leghorn females were injected intramuscularly with TAM on alternate days at doses of 0.1 mg (0.1 TM), 1 mg (1TM), 5 mg (5TM) and 10 mg/kg body weight (10TM) respectively, while the controls were injected with maize oil (vehicle). The experiment was terminated at 23 weeks of age, when all the control hens laid eggs. Sample autopsies were made on chicks of 6, 14 and 23 weeks of age. 3. Body growth was not affected by any of the treatments. 4. Comb growth was accelerated by all doses of TAM, while hematocrit increased in the 1TM, 5TM and 10TM hens. 5. Egg laying advanced in the 0.1TM and 1TM birds, was delayed in 5TM hens and did not occur at all in the 10TM females. 6. TAM caused a precocious increase in plasma oestrogen and androgen, suppressed adiposity in a dose-related manner and, at low doses, advanced the development of the gonadal system. 7. At 23 weeks of age, when the gonadal system of the controls was fully active, TAM caused a dose-related depression in abdominal fat, liver, ovary, and oviduct weights, plasma total lipids and calcium concentrations and a dose-related increase in plasma oestrogen and androgen titres, and comb weight. 8. It seems that TAM increased gonadotropic activity and its androgen stimulating action, but suppressed peripheral signs of the elevated plasma oestrogen titres. Low doses of TAM enhanced gonadotropic activity and egg laying but the antioestrogenic effect depressed development of the gonadal system, suppressing egg production when high doses were administered. It therefore seems that oestrogens are necessary for normal ovarian development in hens.

Androgens↗
PubMed1999

Effects of transient treatment with 6-N-propyl-2-thiouracil on testis development and function in breeder turkeys.

Experiments were conducted to address recent reports of precocial testis development or testicular hypertrophy induced by the anti-thyroid agent 6-N-propyl-2-thiouracil (PTU) in domestic fowl and rodents. In three experiments, PTU was administered to male turkeys during different stages of development. The PTU was given in the feed at a concentration of either 0.1 or 0.5% and effects on thyroid hormones were measured. Periods of PTU treatment were 8 to 16 or 10 to 18 wk of age (Experiment 1); 0 to 8, 0 to 16, and 8 to 16 wk of age (Experiment 2); and 8 to 16 and 20 to 35 wk of age (Experiment 3). Data were collected to determine the effect of PTU treatment on testicular growth (weight), sexual maturation (semen onset and plasma testosterone concentrations), and early adult testicular function in terms of semen quantity (semen volume and sperm concentration) and quality (sperm viability and fertilizing ability). The 0.1% PTU treatment at 8 to 16 wk of age in Experiment 1 resulted in greater testis weights and sperm production than those of untreated controls at 24 wk of age. The difference was absent by 36 wk of age. Likewise, in Experiment 2, onset of semen production was advanced by about 2 wk by the 8 to 16 wk treatment as compared to untreated controls (23.3 vs 25.9 wk), although, at 32 and 36 wk of age neither the quantity nor quality of semen were significantly affected. Also in Experiment 2, 0.1% PTU treatment from 0 to 8 or 0 to 16 wk of age delayed the onset of semen production and depressed semen volumes at 32 and 36 wk of age without affecting semen quality. In Experiment 3, the mean age at the onset of semen was not significantly affected by 0.5% PTU treatment from 8 to 16 or 20 to 35 wk of age. In addition, semen volume and quality at 32 and 36 wk of age was similar to controls. It was concluded that antithyroid treatment with PTU was dependent on dose and time of treatment for effects on both sexual development and early reproductive performance. Precocial development and associated hypertrophy of the testes occurred but was transient. Thereafter, during initial reproductive function, semen quantity and quality were normal.

Aging↗
PubMed2002

The role of SF1 in adrenal and reproductive function: insight from naturally occurring mutations in humans.

Steroidogenic factor 1 is a monomeric orphan nuclear receptor and one of several hundreds of transcription factors encoded in the human genome. It regulates the transcription of many genes involved in gonadal development, sexual differentiation, steroidogenesis and reproduction. Recently, mutations in the gene encoding SF1 have been identified in several patients with primary adrenal failure and 46,XY sex-reversal. Interpreting the consequences of these mutations provides further understanding of transcription factor haploinsufficiency in human genetic disease as well as the exquisite sensitivity of humans to gene-dosage effects during adrenal and gonadal development.

Adrenal Gland Diseases↗
PubMed2002

[Growth and development in untreated girls with slowly progressing idiopathic central or borderline-onset puberty].

OBJECTIVE: To analyse growth and development of girls with slowly progressive idiopathic precocious or early puberty. DESIGN: Long-term open clinical study. SETTING: Department of Obstetrics and Gynaecology, Second Faculty of Medicine, Charles University, Prague. METHODS: In 20 untreated girls with slowly progressive puberty starting at 6-9 years neurogenic aetiology was excluded. During follow-up period 4.7 +/- 2.2 (2-8.5) years (mean +/- SD; range), sexual development (Tanner criteria), age at menarche, menstrual cycle and auxological parameters were evaluated. RESULTS: 13 girls reached menarche at 11.1 +/- 0.9 years (3.7 +/- 1.1 years after the onset of puberty), earlier than in their mothers (12.9 +/- 1.1 years) and Czech standards (P < 0.05). Menstrual cycle 28 (24-29) days was regular in all 6 girls with gynaecological age > 2 years. In one girl microprolactinoma was diagnosed, therapy with bromocryptine started at the age 14.7 years (3.5 years after menarche). At the onset of follow-up, bone age (TW20) advancement was 1.8 +/- 1.4 years above the chronologic age. Initial prediction of final height (graphic method) was 162.3 +/- 5.5 cm vs final prediction 163.7 +/- 5.1 cm. Final height 162.2 +/- 5.7 cm achieved 7 girls vs target height 163.6 +/- 5.2 cm (NS). CONCLUSION: In untreated girls, menarche occurred later after the first signs of puberty than in normal population, menstrual cycle was regular. Height potential was preserved, final height corresponded with their target height. Not all girls with early and slowly progressive puberty should be treated. Therapy is necessary in organic aetiology, rapid progressive precocious puberty and impaired growth prognosis.

Body Constitution↗
PubMed1992

Male pseudohermaphroditism: clinical management, diagnosis and treatment.

Male pseudohermaphroditism (MPH) is a disorder of sexual differentiation whereby the external genitalia are at variance with a male karyotype and the presence of testes. Abnormalities of Leydig cell function are an important cause of MPH, but postnatal age must be considered when interpreting the testosterone response when HCG stimulation is used as a diagnostic test. Androgen insensitivity is also a common cause of MPH; the specific defect in androgen receptor function is currently the subject of intense study, using a combination of biochemical assays and molecular analysis of the androgen receptor gene. The treatment of MPH is influenced by genital tissue responsiveness to androgens and the technical complexity of reconstructive surgical procedures. There is a need for information on the outcome of MPH treatment regarding pubertal development, sexual performance and fertility.

Androgens↗
PubMed1996

Does the male reproductive performance depend on the early lactation milk in rats?

This study investigated the role of the early lactation milk (ELM) on the male reproductive performance and the participation of GnRH on this effect in Wistar rats. Newborn males were divided into three experimental groups: 1) ELM-deprived pups, 2) ELM-deprived pups treated with exogenous GnRH 1, 7, 25, and 31 h after birth, and 3) non-ELM-deprived and without exogenous GnRH. In relation to the other two groups, the ELM-deprived male rats exhibited as adults: reduced fertility, decreased weight of both vas deferens and seminal vesicle, and reduced levels of fructose in the seminal vesicle and prostate gland. We suggest that the intake of ELM during the neonatal period is important to the later sexual development of rats, and that GnRH is somehow involved in such an effect.

Animals↗