ISSN:1051-2144    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1051-2144    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1051-2144    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ACTH-independent cortisol production in adrenal Cushing's syndrome previously was believed to be autonomous. Recent work by our group and others has shown that, in certain patients with bilateral macronodular adrenal hyperplasia or unilateral adrenocortical tumor, cortisol production may be under the control of abnormal or ectopic hormone receptors. The aberrant regulation of cortisol production by GIP, vasopressin, β-adrenergic agonists, hCG/LH, or serotonin illustrates this concept. The identification of an abnormal adrenal receptor offers the possibility of new pharmacological approaches to control hypercortisolism by suppressing the endogenous ligands or by blocking the abnormal receptor with specific antagonists. This review will describe the in vivo investigation protocols utilized by our group to identify the presence of abnormal hormone receptors in primary adrenal Cushing's syndrome.

ISSN:1051-2144    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Selective adenomectomy is the preferred treatment option for most pituitary adenomas, other than prolactinomas. Its safety and efficacy in the management of secreting or nonsecreting micro- or macroadenomas are well established. Pre- and postoperative endocrine management include, among other things, evaluation of pituitary function with particular attention to the hypothalamic-pituitary-adrenal axis (HPA-A). Published data involving a large number of patients demonstrate that when the HPA-A is normal preoperatively, corticosteroids are not necessary before, during, or after surgery. However, patients should be monitored postoperatively to document adequate adrenal function. In contrast, patients with preoperative impairment of HPA-A function as well as those with pituitary tumor apoplexy are given glucocorticoids before, during, and immediately after surgery. Thereafter, corticosteroids can be discontinued abruptly and patients monitored for possible recovery of HPA-A. The latter is conveniently done by measuring serum cortisol levels twice daily. Alternatively, glucocorticoids can be continued for several weeks when HPA-A can be assessed in detail. We prefer the former option because it provides rapid assessment of HPA-A without jeopardizing the patient's well being. Patients with ACTH-secreting pituitary adenomas are not given steroid during or after surgery. Instead, they are closely monitored after adenomectomy for clinical and/or biochemical evidence of adrenal insufficiency. Once the latter is documented, glucocorticoid replacement therapy is initiated and continued until HPA-A returns to normal. The latter approach provides rapid assessment of the completeness of adenomectomy without jeopardizing patient care.

ISSN:1051-2144    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Developmentally, anatomically and histologically, bones are not all the same. A number of studies over several years has raised the issue of osteoblast heterogeneity. These include observations on the diverse behavior of clonal cell lines from both tumor and normal osteogenic tissue, on the heterogeneous occurrence of disease in different parts of the skeleton, and on the response of different parts of the skeleton to therapeutic interventions. More recent observations on the biochemical make-up of different bones and different regions of bones and on the molecular profiles of osteoblasts associated with different skeletal sites are giving new insights. The accumulating evidence indicates that osteoblasts in different maturational states, in different environments, and in different microenvironments, express diverse gene repertoires. The diversity extends to expression of bone matrix molecules, transcription factors, hormones and cytokines, and their receptors. The data support the view that there is not a single unique phenotype characterizing all osteoblasts, but rather that different expressed gene repertoires are associated with distinct osteoblast subpopulations and that this molecular diversity may reflect a need for functional diversity in osteoblasts engaged in different activities.

ISSN:1051-2144    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The osteoblast is the bone-forming cell. The molecular basis of osteoblast-specific gene expression and differentiation is beginning to be understood. Osf2/Cbfa1, the protein that binds to OSE2, an osteoblast-specific cis-acting element present in the Osteoccdcin promoter, recently has been identified as a transcriptional activator of osteoblast differentiation. Osf2/Cbfa1 is a member of the runt family of transcription factors expressed in the mesenchymal condensations of the developing skeleton and in cells of the osteoblast lineage. Osf2/Cbfa1 binds to and regulates the expression of multiple genes expressed in osteoblasts, and forced expression of Osf2/Cbfa1 in nonosteoblastic cells induces the expression of the principal osteoblast-specific genes. Osf2/Cbfa1 gene inactivation in mice leads to failure of mesenchymal progenitor cells to differentiate into osteoblasts. Lastly, heterozygous mutations in the Osf2/Cbfa1 gene cause Cleidocranial dysplasia in humans and mice, a condition marked by generalized bone defects. These results demonstrate that Osf2/Cbfa1 controls osteoblast differentiation and that its function is nonredundant with the function of other gene products during development.

ISSN:1051-2144    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

A normal frequency and amplitude of go nadotropin-releasing hormone (GnRH) secretion from the hypothalamus is critical for both the initiation and maintenance of reproductive function in the human. Hypogonadotropic hypogonadism (HH) is the clinical syndrome that results from absence, decreased frequency, or decreased amplitude of pulsatile GnRH release. Typically, the diagnosis of GnRH deficiency is made in adolescence when secondary sexual characteristics fail to develop. In a subset of patients, HH may present postpubertally with decreased libido, impotence, and oligo- or azoospermia in men and secondary amenorrhea and infertility in women. HH can be congenital or can arise from a variety of structural or functional lesions of the hypothalamic-pituitary axis. Congenital GnRH deficiency can be an isolated finding, as in idiopathic hypogonadotropic hypogonadism, or it may occur in association with anosmia a variety of midline defects, in which case the term Kallmann's syndrome is applied. One-third of cases of congenital HH are familial. Autosomal inheritance is the commonest mode of inheritance, although X-linked transmission due to a mutation in the KAL gene is the best genetically characterized form of GnRH deficiency.In prepubertal patients, sex steroid replacement is necessary to allow normal development of secondary sexual characteristics. In adult women, estrogen replacement with an oral contraceptive or with conjugated estrogens and a progestogen is important to protect bone mass. Androgen replacement in adult men with HH may take the form of either an intramuscular or transdertnal preparation. The fertility potential of patients with HH is generally excellent. Ovulation may be induced in more than 90% of HH women with either gonadotropin therapy or with intravenous pulsatile GnRH. GnRH therapy has the advantage of not causing higher order multiple births. In GnRH-deficient men, spermatogenesis can be stimulated using the combination of hCG and FSH or with pulsatile subcutaneous GnRH therapy. Although both are very effective therapeutic modalities, testicular growth is greater and the time taken to achieve spermatogenesis is shorter in patients treated with GnRH.

ISSN:1051-2144    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Primary thyroid lymphoma (PTL) is a rare neoplasm, predominantly affecting elderly women. Its etiology and appropriate classification are controversial. This review provides a comprehensive description of clinical and pathologic features of PTL and discusses current concepts regarding pathogenesis and nosology. These are considered in our recommendations regarding diagnosis and management.

ISSN:1051-2144    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The Hippocratic doctrine of the four humors and qualities has been assumed as a precursor of modern endocrinology. There is a clinical endocrinologic case in theHippocratic Aphorism.V, #39, probably describing the galactorrhea-amenorrhea syndrome in a nonpregnant woman. ThisAphorismdeserves particular attention because it appears to be one of the first clear descriptions of an endocrine syndrome.

ISSN:1051-2144    

出版商:OVID    

年代:1999

数据来源: OVID