摘要:

During the past 20 yearsin vitrofertilization (IVF) has become the treatment of choice for an increasing number of infertile couples. An understanding of the physiologic basis for this advanced procedure is critical to the appropriate selection of patients, choice of stimulation protocols, and use of adjuvant therapies. In addition, an understanding of the pathophysiology of the ovarian hyperstimulation syndrome may allow novel treatment of this potentially life-threatening iatrogenic complication.

ISSN:1068-3097    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:1068-3097    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

SHOX(short staturehomeobox-containing gene) is the first gene that has been shown to be relevant to the development of specific features in Turner syndrome. Clinical studies in individuals withSHOXhaploinsufficiency caused by intragenic mutations, pseudoautosomal microdeletions, and cytogenetically recognizable Xp deletions have shown thatSHOXhaploinsufficiency causes not only short stature but also Turner skeletal features such as cubitus valgus, short metacarpals, Madelung deformity, high arched palate, and short neck, and that expressivity ofSHOXhaploinsufficiency in the limb and faciocervical regions is primarily influenced by gonadal function status and the presence or absence of the lymphogenic gene, respectively. The prevalence ofSHOXhaploinsufficiency is estimated as approximately 2% for idiopathic short stature and 60 to 80% for Léri-Weill dyschondrosteosis (LWD) characterized by Madelung deformity. Individuals with LWD and/or mesomelic short stature and familial members of a proband withSHOXhaploinsufficiency should be examined forSHOXhaploinsufficiency. Growth hormone and gonadotropin-releasing hormone analog may provide effective treatment for individuals withSHOXhaploinsufficiency.

ISSN:1068-3097    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Growth hormone (GH) insensitivity syndrome is a genetic disorder characterized by resistance to the biologic effects of GH, deficiency of IGF-I and IGFBP-3, and hypersecretion of GH. Clinically the most severe form, Laron syndrome, combines a dysmorphic phenotype, extreme short stature, and spontaneous hypoglycemia. The genetic defect consists of a range of mutations of the GH receptor (GHR) gene. Heterogeneity has been demonstrated by the study of a large multi-ethnic population who fulfilled the biochemical criteria of GH insensitivity but varied in clinical and endocrine characteristics. Patients without the dysmorphic features of Laron syndrome are designated partial or atypical GHIS and overlap with the condition of idiopathic short stature (ISS). Defects of theGHRhave been demonstrated as a rare cause of ISS, and diagnostic methods for partial GH insensitivity are being studied. Treatment of GHIS with recombinant IGF-I has demonstrated a growth-promoting effect, though inferior to that of hGH in GH deficiency. Trials of IGF-I are limited by shortage of supplies although the use of the IGF-I/IGFBP-3 complex may offer real potential.

ISSN:1068-3097    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

International adoptions are becoming a growing option for families in the United States. The children arriving often come from inadequately funded state-run institutions generally lacking in the basics of human life. This places the children at risk for a wide variety of medical, psychologic and developmental abnormalities. One of the most consistent findings on arrival is short stature. The etiology of this “institutional short stature” is unknown and likely multifactorial. Fortunately most children, soon after arrival, experience catch-up in growth, making early evaluation of their stunting generally unnecessary. Final height gains may however, be limited because of a risk of early and rapidly progressing puberty. Further studies are needed to understand the etiology of both the growth changes and early puberty, as more physicians become involved in the care of these unique children.

ISSN:1068-3097    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Polycystic ovarian syndrome (PCOS) is believed to be the most common endocrinopathy affecting women in the reproductive age group. It is increasingly being recognized in adolescent girls who seek treatment for signs and symptoms of hyperandrogenism and is frequently but not universally associated with obesity. A major component of the syndrome is insulin resistance or hyperinsulinemia, which is proposed to play a pathophysiologic role. There are convincingin vitro, in vivo,and therapeutic intervention studies to suggest that insulin stimulates ovarian androgen secretion leading to functional ovarian hyperandrogenism. A significant proportion of patients with PCOS also have functional adrenal hyperandrogenism, which is also thought to be mediated through insulin-stimulating adrenal androgen secretion. Besides its gynecologic consequences, PCOS is associated with increased risk for impaired glucose tolerance and type 2 diabetes, dyslipidemia, and cardiovascular sequelae. These derangements are present early in the course of the PCOS in the adolescent age group. Retrospective clinical data would suggest that in some cases premature adrenarche may herald future PCOS in adolescents. Though there are no robust epidemiologic data, there is an overall clinical impression that PCOS is increasing among adolescents. It is tempting to speculate that the epidemic of obesity afflicting US children may be the driving force. Obesity with its resultant insulin resistance or hyperinsulinemia may trigger or unmask the syndrome in genetically predisposed individuals. It remains to be determined if insulin sensitizers play a role in the management of PCOS in the pediatric age group.

ISSN:1068-3097    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Follicular thyroid tumors represent a range of subtypes including ordinary adenomas, atypical adenomas, and minimally and widely invasive carcinomas, the distinction of which is crucial for adequate treatment and clinical handling. Whereas today an accurate diagnosis can only be made by histopathologic examination of specimens obtained at surgery, all patients with a follicular tumor diagnosed by preoperative fine-needle aspiration will eventually be subjected to surgery. However, it is expected that new prognostic and theurapeutic tools will emerge from the improved understanding of sporadic and familial follicular tumorigenesis. The recent genetic and other findings which have revealed promising data regarding these issues include the recognition of PTEN mutations underlying Cowden disease in familial cases and the description of the PAX8/PPAR&ggr;1 fusion and the immunohistochemical detection of galectin-3 overexpression suggested to be characteristic of the cancerous phenotype.

ISSN:1068-3097    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Follicular thyroid tumors represent a range of subtypes including ordinary adenomas, atypical adenomas, and minimally and widely invasive carcinomas, the distinction of which is crucial for their adequate treatment and clinical handling. Whereas today the diagnosis can only be accurately made by histopathologic examination of specimens obtained at surgery, all patients with a follicular tumor diagnosed by preoperative fine-needle aspiration will eventually be subjected to surgery. However, it is expected that new prognostic and therapeutic tools will emerge from the improved understanding of sporadic and familial follicular tumorigenesis. Recent genetic and other findings that have revealed promising data regarding these issues include the recognition of PTEN mutations underlying Cowden disease in familial cases, the description of the PAX8/PPARg1 Fusion, and the immunohistochemical detection of galectin-3 over-expression suggested to be characteristic of the cancerous phenotype.

ISSN:1068-3097    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The molecular pathogenesis of pituitary disorders is complex and has been explored in animal models and human subject studies. Hormone deficiencies are largely caused by mutations in transcription factors required for pituitary differentiation. Early developmental genes (Rpx, Lhx3, Lhx4, Pitx2) pleiotropically affect multiple pituitary hormones and adjacent physical structures, whereas genes determining specific pituitary lineages (includingProp1, Pit1, SF1, DAX1, Tpit) are involved in single or combined hormone deficiencies. Excess hormone secretion is mostly associated with monoclonal pituitary adenomas. Genes identified for familial pituitary tumor syndromes affect transcription (MEN1) and hypothalamic hormone signaling (CNC1, gsp). Murine gene-disruption studies (Rb, p27, p18) implicate cell-cycle regulatory genes, some of which have altered expression in most human pituitary tumors (p16, p27). Aberrant expression ofPTTG, a mammalian securin homolog, can lead to chromosome missegregation, an early step in multistep pituitary tumor progression. Excess hypothalamic trophic hormones lead to pituitary hyperplasia and hormone excess, whereas alterations in hypothalamic hormone receptor genes are uncommon.

ISSN:1068-3097    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

During the past 10 years susceptibility genes have been identified for inherited cancer syndromes involving pheochromocytomas including multiple endocrine neoplasia type 2, caused by germline mutations in theRETproto-oncogene and von Hippel-Lindau disease, caused by germline mutations of the tumor suppressor geneVHL. More recently, the role of the mitochondrial complex II peptides in the tumorigenesis of paragangliomas has unfolded. The challenge for the future is to further clarify the normal functions of the genes involved in the tumorigenesis of pheochromocytomas and paragangliomas and the mechanisms by which their activation or inactivation leads to the tumorigenic phenotype. This review focuses on recent developments in the genetics of pheochromocytomas and paragangliomas and the significance of these genetic changes to understanding the disease phenotype, not only in familial but also in sporadic disease.

ISSN:1068-3097    

出版商:OVID    

年代:2002

数据来源: OVID