ISSN:1068-3097    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:1068-3097    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Recent advances in our understanding of the transplantation of stem cells and their differentiation to tissue-specific phenotypes, as well as methods for introducing genes into subpopulations of stem cells greatly expands the potential for therapeutic strategies to correct genetic, metabolic, and degenerative disorders of the skeleton. The use of mesenchymal stem cells for systemic diseases, such as osteoporosis, and local repair of skeletal defects by tissue engineering is emphasized. Current procedures and planned future approaches that are under investigation will be discussed in this review.

ISSN:1068-3097    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Insulin-like growth factor I is a potent growth and differentiation factor in many tissues, especially the skeleton. The precise role and regulation of this peptide has come under increasing scrutiny by investigators interested in understanding the pathogenesis of osteoporosis and the potential role of insulin-like growth factor I as a treatment modality. Insulin-like growth factor I in bone is derived from osteoblast synthesis and from the systemic circulation. Its biologic activity is regulated by a complex and redundant system including a family of insulin-like growth factor binding proteins, targeted proteases, two insulin-like growth factor receptors, and local and systemic factors. A strong genetic program for bone and the liver also contributes to the expression of this peptide, but the mechanisms have not been delineated.In vitrostudies have illustrated the critical role insulin-like growth factor I plays in the maintenance of the differentiated osteoblast phenotype and in the mediation of parathyroid hormone's anabolic actions on the skeleton. Insulin-like growth factor I may also be important in the recruitment of osteoclasts. Recent advances in genomic engineering have allowed scientists to appreciate better the importance of insulin-like growth factor I in bone formation regulation and in bone mineralization. Future studies will help determine if insulin-like growth factor I could be used as an anabolic agent in the treatment of osteoporosis.

ISSN:1068-3097    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Transplantation osteoporosis causes significant morbidity in the growing population of survivors of organ transplantation. Rapid bone loss and increased fracture rates, particularly in the first 6 to 18 months after transplantation, have been associated with the independent and combined effects of immunosuppressive medications such as glucocorticoids, cyclosporine, and tacrolimus. In contrast to the low-turnover bone disease found in glucocorticoid-induced osteoporosis, a high-turnover state is found in the posttransplant period. No pretransplantation variables reliably predict posttransplantation bone loss or fracture risk in the individual patient. As a result, preventative therapy should be considered in all organ transplant recipients. Such therapy should be instituted immediately after transplantation, because most bone loss occurs during this early period. Preventive regimens including calcium, vitamin D metabolites, hormone replacement therapy, calcitonin, and bisphosphonates have been studied. Currently, antiresorptive therapy with bisphosphonates is the most promising approach to the prevention and treatment of transplantation osteoporosis.

ISSN:1068-3097    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Mutational analysis of the gonadotropin and gonadotropin receptor genes is an exciting and continuously developing field. Much has been learned from the first mutants identified in patients with clear and expected phenotypes: infertility or extreme precocious puberty in boys. Absence of follicle-stimulating hormone or luteinizing hormone action as result of gene alterations has strong effects on the gonadal targets of these hormones. However, most patients in the clinic are not examined for such severe phenotypes, but show symptoms such as decreased fertility with no obvious cause or widespread complex clinical syndromes such as polycystic ovary syndrome. This review discusses some of the recent advances in the field: new and interesting mutations in the luteinizing hormone receptor gene, polymorphisms in genes for the gonadotropins and their receptors, the findings in the luteinizing hormone receptornullmouse, and the possible significance of nongonadal luteinizing hormone receptor expression.

ISSN:1068-3097    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Müllerian inhibiting substance is a gonadal peptide hormone that causes regression of the müllerian ducts in the male fetus and modulates Leydig cell proliferation and steroidogenesis in the postnatal testis. Determination of müllerian inhibiting substance has proven to be a useful diagnostic tool for assessment of the testes in children with nonpalpable gonads, including those with intersex conditions. Müllerian inhibiting substance measurement may also have clinical relevance for the evaluation of mature testicular function and spermatogenesis. Recent studies have confirmed a role for müllerian inhibiting substance as a tumor marker for ovarian tumors and in the histologic characterization of granulosa cell tumors and other sex cord tumors. One active area of clinical research is the potential pharmacologic applications of müllerian inhibiting substance in the fields of male infertility and oncology.

ISSN:1068-3097    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Testosterone is required not only for virilization and normal sexual function, but also for stimulating and maintaining normal bone and muscle mass in men. The past decade has seen a number of important advances in androgen replacement with the addition of transdermal patch and gel formulations to the long-available intramuscular testosterone esters. The advent of more patient-friendly preparations has, in turn, contributed to an expansion of the clinical indications for testosterone therapy to include not only overt hypogonadism but also wasting disorders and aging. However, the potential benefit of testosterone in the aging male is still controversial and awaits the results of large, randomized, placebo-controlled trials. All patients receiving testosterone therapy require measurement of serum testosterone levels to titrate the optimal dose, in addition to monitoring of hematocrit, liver function tests, a lipid profile, and prostate-specific antigen.

ISSN:1068-3097    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Behaviors that activate the hypothalamic–pituitary–adrenal (HPA) axis or suppress the hypothalamic–pituitary–thyroidal (HPT) axis can disrupt the hypothalamic–pituitary–gonadal axis in women and men. Individuals with functional hypothalamic hypogonadism typically display a combination of behaviors that serve as psychogenic stressors or present metabolic challenges. Reproductive recovery depends on restoration of the HPA and HPT axes. Hormone replacement regimens have limited benefit because they do not fully restore endocrine and metabolic homeostasis and their use masks deficits that accrue from altered HPA and HPT function. Long-term deleterious consequences of stress-induced anovulation may include an increased risk of cardiovascular disease, osteoporosis, depression, and dementia. Although fertility can be restored with exogenous administration of gonadotropins or pulsatile GnRH, fertility management alone will not permit recovery of the HPA and HPT axes. HPA activation and HPT suppression are linked to poor obstetrical and fetal outcomes. In contrast, behavioral and psychologic interventions that address problematic behaviors and attitudes engender full endocrine recovery, thus offering better individual, maternal, and child health.

ISSN:1068-3097    

出版商:OVID    

年代:2001

数据来源: OVID