摘要:

University of Virginia Health Sciences Center, Department of Pediatrics, Division of Endocrinology, Box 386, Barringer V, Room 5402, Charlottesville, VA 22908, USA.

ISSN:1068-3097    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Sexual differentiation is a multistep process in which genetic information is translated into phenotype. Disorders in any of these steps can result in ambiguity of the genitalia. The differential diagnosis requires a systematic approach, with determination of the genetic sex (karyotype), careful description of the internal genital structures, and determination of the hormonal milieu. Confirmation of the diagnosis with molecular and biologic studies is now possible in many disorders of intersex. This article provides a review of the differential diagnosis and therapeutic options of disorders causing ambiguous genitalia, with emphasis on new developments in the field.

ISSN:1068-3097    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The measurement of body composition has become important in clinical endocrinology and endocrine research because often it is necessary to assess the metabolic effects of hormones on bone, adipose, and lean tissues. All human body composition methods are based on prediction models thatindirectly estimatethe true body composition with various amounts of error. Prediction error can be minimized if the investigator understands the assumptions of each model. When the assumptions are violated, large errors of estimation may occur. Accurate body composition assessments are difficult to achieve during puberty. For instance, despite its popularity as a clinical body composition model, dual-energy x-ray absorptiometry has not been shown to accurately predict the body composition of children and adolescents. The measurement of total body water to estimate the body composition of children is often used inappropriately because the investigator assumes that the fat-free mass of a child has a proportional water content equivalent to that of an adult. This article reviews the assumptions and validity of body composition models commonly used in endocrinology. As highlighted in a review of recent research on the relationships between body composition and leptin, growth hormone, and insulin resistance, inaccurately estimating the body composition makes it difficult to describe precisely the relationship between body composition and hormone release or the metabolic effects of hormone therapy. The use of inaccurate body composition models also makes it difficult to compare the results of various studies.

ISSN:1068-3097    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Polycystic ovary syndrome (PCOS) is the most common cause of hyperandrogenism in women of reproductive age and is often accompanied by hyperinsulinemia and adrenal androgen excess. Overactive steroidogenesis due to dysregulation of ovarian cytochrome P450c17α, predominantly at the level of 17,20-lyase activity, seems to underlie most PCOS cases. Abnormalities in luteinizing hormone pulsatility or frequency, extraovarian androgen excess, hyperinsulinemia, and increased insulinlike growth factor(s) secretion have been suggested as possible pathogenetic mechanisms for ovarian hyperandrogenism development. Several lines of evidence suggest that most of these abnormalities may have a prepubertal or peripubertal onset. For example, the persistence of the high luteinizing hormone circadian profile characteristic of puberty in some subsets of otherwise healthy anovulatory adolescents may herald the development of the typical PCOS pattern of luteinizing hormone hypersecretion. Further, an exaggerated ovarian androgen synthesis beginning at the early stages of pubertal development has been found in girls with a history of premature pubarche, a cohort with a well-known increased incidence of ovarian hyperandrogenism at adolescence. Hyperinsulinemia and decreased sex hormone-binding globulin and insulinlike growth factor binding protein-1 levels seem to precede these ovarian abnormalities. Overall, these data suggest that at least in some subsets of patients, PCOS may have a peripubertal onset. Increased serine phosphorylation of adrenal-ovarian cytochrome P450c17α (causing adrenal and ovarian hyperandrogenism) and an increase in the serine phosphorylation of insulin receptors (provoking insulin resistance) have been proposed as a unifying pathogenetic mechanism for the three principal features of PCOS. The genetic basis for these processes remains to be established.

ISSN:1068-3097    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

A summary of the majority of available uncontrolled studies showed that the final height attainment over predicted adult height for 322 children with idiopathic short stature treated with growth hormone (GH) was only 2.85 cm (+0.49 SDS). Further, a summary of seven studies reported that the spontaneous outcome in children with untreated idiopathic short stature was more than 1 SDS in final height compared with height at presentation, and patients with delayed puberty gained more than 2 SDS as adults. A reevaluation has concluded that short stature is not associated with clinically significant psychologic morbidity, and the psychologic outcome in response to GH treatment of the short normal child showed no discernible difference in psychologic benefit, despite a difference in height gained. A recent editorial strongly advised against the expanded use of GH in the normal short child.

ISSN:1068-3097    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:1068-3097    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The gene responsible for multiple endocrine neoplasia type 1 (MEN 1), a familial neoplasia syndrome involving mainly the parathyroid glands, endocrine enteropancreas, and anterior pituitary gland, has recently been identified. This has allowed mutation analysis of theMEN1gene in MEN 1 families, families with MEN 1 -like syndromes, sporadic MEN 1 cases, and tumors. A wide spectrum of mutations distributed across the nine coding exons have been found in all except MEN 1 -like syndromes. However, so far there is no obvious genotype-phenotype correlation. This article summarizes these recent developments, especially in regard to the clinical and genetic aspects of MEN 1, and discusses their impact on clinical application and future research.

ISSN:1068-3097    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Deletions along both the short and the long arms of chromosome 10 have been prominent in both benign and malignant epithelial thyroid tumors as well as carcinomas of the endometrium, prostate, and brain. It is therefore believed that chromosome 10 houses several tumor suppressor genes that could be involved in the pathogenesis of these tumors. Recently, a novel tumor suppressor gene calledPTEN/MMAC1/TEP1was isolated from an interval on chromosome arm 10q that shows deletions in thyroid, brain, and prostate tumors. Germline mutations inPTENhave been found in Cowden syndrome, an autosomal dominant inherited cancer syndrome characterized by multiple hamartomas and a high risk of benign and malignant thyroid tumors and breast cancers. It is also believed that endometrial carcinomas and brain tumors are part of the spectrum of Cowden syndrome but not prostate cancer. With the identification of the Cowden disease susceptibility gene, DNA-based predictive testing may be offered. Somatic mutations inPTENhave been described in sporadic thyroid tumors, endometrial carcinomas, prostate carcinomas, and glioblastoma multiforme. Although initial analyses suggest that somaticPTENalterations appear to be associated with more advanced disease in carcinomas of the prostate and brain, this does not appear to be the case in epithelial thyroid tumors.

ISSN:1068-3097    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:1068-3097    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Many neuropeptides and their receptors have been found within immune tissues, and a host of functions have been assigned to them. Some information has been gained from observations of immune responses to exogenously administered neuropeptides, but many immunoneuropeptides differ in structure and probably also in function from their analogous forms found in hypothalamic and pituitary tissues. New strategies, such as oligonucleotide antisense probes and gene-targeting models, can be used to determine physiologic roles for immunoneuropeptides. Immunoneuropeptides can respond to physiologic or pharmacologic manipulation, and evidence is mounting for important roles in mediating immune responses to inflammation and stress, as well as being instrumental in controlling cell growth. The ability to modulate immune functions through autocrine and paracrine mechanisms confers cytokine status on immunoneuropeptides, which, activated in response to stress or infection, have the potential to maintain a homeostatic balance between the immune, neural, and endocrine systems during periods of stress or illness.

ISSN:1068-3097    

出版商:OVID    

年代:1998

数据来源: OVID