92 research outputs found
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Development of the human prepuce and its innervation.
Development of the human prepuce was studied over the course of 9-17 weeks of gestation in 30 specimens. Scanning electron microscopy revealed subtle surface features that were associated with preputial development, namely the appearance of epidermal aggregates that appeared to be associated with formation of the preputial fold. Transverse and sagittal sections revealed that the epidermis of the glans is considerably thicker than that of the penile shaft. We described a novel morphogenetic mechanism of formation of the preputial lamina, namely the splitting of the thick epidermis of the glans into the preputial lamina and the epidermis via the intrusion of mesenchyme containing red blood cells and CD31-positive blood vessels. This process begins at 10-11 weeks of gestation in the proximal aspect of the glans and extends distally. The process is likely to be androgen-dependent and mediated via androgen receptors strategically localized to the morphogenetic process, but signaling through estrogen receptor may play a role. Estrogen receptor alpha (ESR1) has a very limited expression in the developing human glans and prepuce, while estrogen receptor beta (ESR2) is expressed more broadly in the developing preputial lamina, epidermis and urethra. Examination of the ontogeny of innervation of the glans penis and prepuce reveals the presence of the dorsal nerve of the penis as early as 9 weeks of gestation. Nerve fibers enter the glans penis proximally and extend distally over several weeks to eventually reach the distal aspect of the glans and prepuce by 14-16 weeks of gestation
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Androgen-independent events in penile development in humans and animals.
The common view on penile development is that it is androgen-dependent, based first and foremost on the fact that the genital tubercle forms a penis in males and a clitoris in females. However, critical examination of the complex processes involved in human penile development reveals that many individual steps in development of the genital tubercle are common to both males and females, and thus can be interpreted as androgen-independent. For certain developmental events this conclusion is bolstered by observations in androgen-insensitive patients and androgen receptor mutant mice. Events in genital tubercle development that are common to human males and females include: formation of (a) the genital tubercle, (b) the urethral plate, (c) the urethral groove, (d) the glans, (e) the prepuce and (f) the corporal body. For humans 6 of 13 individual developmental steps in penile development were interpreted as androgen-independent. For mice 5 of 11 individual developmental steps were found to be androgen-independent, which were verified through analysis of androgen-insensitive mutants. Observations from development of external genitalia of other species (moles and spotted hyena) provide further examples of androgen-independent events in penile development. These observations support the counter-intuitive idea that penile development involves both androgen-independent and androgen-dependent processes
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Reproductive tract biology: Of mice and men.
The study of male and female reproductive tract development requires expertise in two separate disciplines, developmental biology and endocrinology. For ease of experimentation and economy, the mouse has been used extensively as a model for human development and pathogenesis, and for the most part similarities in developmental processes and hormone action provide ample justification for the relevance of mouse models for human reproductive tract development. Indeed, there are many examples describing the phenotype of human genetic disorders that have a reasonably comparable phenotype in mice, attesting to the congruence between mouse and human development. However, anatomic, developmental and endocrinologic differences exist between mice and humans that (1) must be appreciated and (2) considered with caution when extrapolating information between all animal models and humans. It is critical that the investigator be aware of both the similarities and differences in organogenesis and hormone action within male and female reproductive tracts so as to focus on those features of mouse models with clear relevance to human development/pathology. This review, written by a team with extensive expertise in the anatomy, developmental biology and endocrinology of both mouse and human urogenital tracts, focusses upon the significant human/mouse differences, and when appropriate voices a cautionary note regarding extrapolation of mouse models for understanding development of human male and female reproductive tracts
A Summary of the Endocrine Society Clinical Practice Guidelines on Congenital Adrenal Hyperplasia due to Steroid 21-Hydroxylase Deficiency
Steroid 21-hydroxylase deficiency accounts for about 95% of cases of congenital adrenal hyperplasia (CAH). Newborns are currently being screened for the classical forms of this disease throughout the United States and in 12 other countries. As such, it seems important to develop the best practice guidelines for treating not only infants and children, but affected adults as well. This report gives a brief overview of the most recent expert opinion and clinical practice guidelines for CAH as formulated by The Endocrine Society Task Force
Embryonic exposure to the fungicide vinclozolin causes virilization of females and alteration of progesterone receptor expression in vivo: an experimental study in mice
BACKGROUND: Vinclozolin is a fungicide that has been reported to have anti-androgenic effects in rats. We have found that in utero exposure to natural or synthetic progesterones can induce hypospadias in mice, and that the synthetic progesterone medroxyprogesterone acetate (MPA) feminizes male and virilizes female genital tubercles. In the current work, we selected a relatively low dose of vinclozolin to examine its in utero effects on the development of the genital tubercle, both at the morphological and molecular levels. METHODS: We gave pregnant dams vinclozolin by oral gavage from gestational days 13 through 17. We assessed the fetal genital tubercles from exposed fetuses at E19 to determine location of the urethral opening. After determination of gonadal sex, either genital tubercles were harvested for mRNA quantitation, or urethras were injected with a plastic resin for casting. We analyzed quantified mRNA levels between treated and untreated animals for mRNA levels of estrogen receptors α and β, progesterone receptor, and androgen receptor using nonparametric tests or ANOVA. To determine effects on urethral length (males have long urethras compared to females), we measured the lengths of the casts and performed ANOVA analysis on these data. RESULTS: Our morphological results indicated that vinclozolin has morphological effects similar to those of MPA, feminizing males (hypospadias) and masculinizing females (longer urethras). Because these results reflected our MPA results, we investigated the effects of in utero vinclozolin exposure on the mRNA expression levels of androgen, estrogen α and β, and progesterone receptors. At the molecular level, vinclozolin down-regulated estrogen receptor α mRNA in females and up-regulated progesterone receptor mRNA. Vinclozolin-exposed males exhibited up-regulated estrogen receptor α and progesterone receptor mRNA, effects we have also seen with exposure to the synthetic estrogen, ethinyl estradiol. CONCLUSION: The results suggest that vinclozolin virilizes females and directly or indirectly affects progesterone receptor expression. It also affects estrogen receptor expression in a sex-based manner. We found no in vivo effect of vinclozolin on androgen receptor expression. We propose that vinclozolin, which has been designated an anti-androgen, may also exert its effects by involving additional steroid-signaling pathways
Current understanding of hypospadias: relevance of animal models
Hypospadias is a congenital abnormality of the penile urethra with an incidence of approximately 1:200-1:300 male births, which has doubled over the past three decades. The aetiology of the overwhelming majority of hypospadias remains unknown but appears to be a combination of genetic susceptibility and prenatal exposure to endocrine disruptors. Reliable animal models of hypospadias are required for better understanding of the mechanisms of normal penile urethral formation and hence hypospadias. Mice and/or rats are generally used for experimental modelling of hypospadias, however these do not fully reflect the human condition. To use these models successfully, researchers must understand the similarities and differences between mouse, rat and human penile anatomy as well as the normal morphogenetic mechanisms of penile development in these species. Despite some important differences, numerous features of animal and human hypospadias are shared: the prevalence of distal penile malformations; disruption of the urethral meatus; disruption of urethra-associated erectile bodies; and a common mechanism of impaired epithelial fusion events. Rat and mouse models of hypospadias are crucial to our understanding of hypospadias to ultimately reduce its incidence through better preventive strategies
Guidelines for the Development of Comprehensive Care Centers for Congenital Adrenal Hyperplasia: Guidance from the CARES Foundation Initiative
Patients with rare and complex diseases such as congenital adrenal hyperplasia (CAH) often receive fragmented and inadequate care unless efforts are coordinated among providers. Translating the concepts of the medical home and comprehensive health care for individuals with CAH offers many benefits for the affected individuals and their families. This manuscript represents the recommendations of a 1.5 day meeting held in September 2009 to discuss the ideal goals for comprehensive care centers for newborns, infants, children, adolescents, and adults with CAH. Participants included pediatric endocrinologists, internal medicine and reproductive endocrinologists, pediatric urologists, pediatric surgeons, psychologists, and pediatric endocrine nurse educators. One unique aspect of this meeting was the active participation of individuals personally affected by CAH as patients or parents of patients. Representatives of Health Research and Services Administration (HRSA), New York-Mid-Atlantic Consortium for Genetics and Newborn Screening Services (NYMAC), and National Newborn Screening and Genetics Resource Center (NNSGRC) also participated. Thus, this document should serve as a “roadmap” for the development phases of comprehensive care centers (CCC) for individuals and families affected by CAH
Guidelines for the Development of Comprehensive Care Centers for Congenital Adrenal Hyperplasia: Guidance from the CARES Foundation Initiative
Patients with rare and complex diseases such as congenital adrenal hyperplasia (CAH) often receive fragmented and inadequate care unless efforts are coordinated among providers. Translating the concepts of the medical home and comprehensive health care for individuals with CAH offers many benefits for the affected individuals and their families. This manuscript represents the recommendations of a 1.5 day meeting held in September 2009 to discuss the ideal goals for comprehensive care centers for newborns, infants, children, adolescents, and adults with CAH. Participants included pediatric endocrinologists, internal medicine and reproductive endocrinologists, pediatric urologists, pediatric surgeons, psychologists, and pediatric endocrine nurse educators. One unique aspect of this meeting was the active participation of individuals personally affected by CAH as patients or parents of patients. Representatives of Health Research and Services Administration (HRSA), New York-Mid-Atlantic Consortium for Genetics and Newborn Screening Services (NYMAC), and National Newborn Screening and Genetics Resource Center (NNSGRC) also participated. Thus, this document should serve as a “roadmap” for the development phases of comprehensive care centers (CCC) for individuals and families affected by CAH
Guidelines for the Development of Comprehensive Care Centers for Congenital Adrenal Hyperplasia: Guidance from the CARES Foundation Initiative
Abstract Patients with rare and complex diseases such as congenital adrenal hyperplasia (CAH) often receive fragmented and inadequate care unless efforts are coordinated among providers. Translating the concepts of the medical home and comprehensive health care for individuals with CAH offers many benefits for the affected individuals and their families. This manuscript represents the recommendations of a 1.5 day meeting held in September 2009 to discuss the ideal goals for comprehensive care centers for newborns, infants, children, adolescents, and adults with CAH. Participants included pediatric endocrinologists, internal medicine and reproductive endocrinologists, pediatric urologists, pediatric surgeons, psychologists, and pediatric endocrine nurse educators. One unique aspect of this meeting was the active participation of individuals personally affected by CAH as patients or parents of patients. Representatives of Health Research and Services Administration (HRSA), New York-Mid-Atlantic Consortium for Genetics and Newborn Screening Services (NYMAC), and National Newborn Screening and Genetics Resource Center (NNSGRC) also participated. Thus, this document should serve as a "roadmap" for the development phases of comprehensive care centers (CCC) for individuals and families affected by CAH
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