ISSN:0002-9629    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

The N-terminus of the atrial natriuretic factor (ANF) prohormone (ie, proANF 1–98) contains two vasodilatory peptides consisting of amino acids (aa): aa 1–30 (ie, proANF 1–30) and aa 31–67 (ie, proANF 31–67) of the 126 aa prohormone. The relationship of this N-terminus to the renin-aldosterone axis and blood pressure reduction was investigated in 18 obese subjects (5 hypertensive and 13 normotensive) placed on a 12-week, low sodium (40 mmol), weight reducing diet. The N-terminus of the ANF prohormone and proANF 31–67, which circulates as a distinct entity after being proteolytically cleaved from the N-terminus, were significantly (p < 0.001) higher (767 ± 1.01 and 816 ± 135 fmol/ml) in the obese hypertensive group compared with the obese normotensive group (377 ± 24 and 356 ± 17 fmol/ml, respectively) prior to beginning the weight reduction program. There was a dramatic fall in the N-terminus and in proANF 31–67 after 1 week of weight reduction in both obese groups, which correlated with the decrease in mean arterial pressure during the first week and throughout the 12 weeks of weight reduction (r = .54, p < 0.001 and r = .59, p < 0.001, respectively). ProANF 1–98 had a significant (p < 0.01) inverse correlation with plasma renin in both obese groups. ProANF 31–67, likewise, had an inverse correlation with plasma renin in the hypertensive (p < 0.002), as well as the normotensive (p < 0.03) subjects. ProANF 31–67 did not significantly correlate with aldosterone in either group. ProANF 1–98 had an inverse correlation with aldosterone only in the normotensive group (r = .33, p < 0.01), but not in the hypertensive group. These results demonstrate that weight loss while ingesting a controlled low sodium diet is accompanied by changes in the N-terminus of the ANF prohormone and proANF 31–67, which correlate with changes in blood pressure and inversely correlate with changes in plasma renin activity (PRA). ProANF 1–98 and proANF 31–67 did not correlate with plasma aldosterone concentration in either group, as ANF has been shown to do previously. These findings reflect recent in vitro data that proANF 1–30 and proANF 31–67 have different mechanisms of action at the cellular level because they do not inhibit angiotensin II-stimulated aldosterone production while ANF does inhibit this secretion.

ISSN:0002-9629    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

This study was designed to compare the clinical efficacy and safety of oral clonidine and oral labetalol in the treatment of severe hypertension in an emergency department setting. Thirty-six patients with severely elevated blood pressure (mean baseline blood pressure 199/132 mm Hg) without acute end-organ dysfunction were treated with either oral labetalol or oral clonidine in a randomized double-blind prospective study. Labetalol was administered as an initial dose of 200 mg, followed by hourly 200 mg doses up to 1,200 mg. Clonidine was administered as an initial dose of 0.2 mg, followed by hourly 0.1 mg doses up to 0.7 mg. Labetalol reduced diastolic blood pressure in 94% of the patients within 6 hours, with a mean reduction in blood pressure of 54/37 mm Hg. Clonidine reduced diastolic blood pressure in 83% of the patients within 6 hours, with a mean reduction in blood pressure of 57/32 mm Hg. The authors conclude that oral labetalol was comparable to clonidine in efficacy, had a similar incidence of side effects, and offered the clinician a useful alternative for the treatment of severe hypertension in an emergency department setting. Further studies are indicated to determine appropriate dosing regimens for oral labetalol in the acute treatment of severe hypertension.

ISSN:0002-9629    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

The authors assayed oncogene alterations in rat colon tumors induced by the direct-acting chemical carcinogen, N-methyl-N-nitrosourea (MNU). DNA isolated from 34 adenomas and eight carcinomas, as well as adjacent normal colon, of 11 rats was assayed by Southern blotting for restriction fragment length polymorphisms and gene amplifications and deletions in 13 oncogenes known to be involved in human or other animal tumors. In addition to finding apparent point mutations or other small alterations in thefosandablgenes in individual rat colon tumors, the authors observed what appear to be larger alterations (ie, rearrangements, or intragenic insertions or deletions) in the H-rasandmybloci in several tumors. In contrast, no changes in the K-ras, N-ras,myc, N-myc,neu, raf, fms, met, andhstgenes were seen in any of these tumors. The frequency ofmybgene alterations was higher in carcinomas than in adenomas, suggesting that these changes occurred relatively late during tumorigenesis and were not direct effects of the carcinogen. In addition, the finding of alterations in two or three oncogenes in several MNU-induced rat colon tumors suggests the possibility of more widespread genomic lesions in this model.

ISSN:0002-9629    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

A 72-year-old woman with 5-year history of essential hypertension developed peritoneal tuberculosis. The patient's hypertension, which had been well-controlled by long-acting nifedipine, deteriorated after the administration of rifampicin, an antitubercular agent. During use of nifedipine and rifampicin, both the peak plasma concentration and the area under the curve of nifedipine decreased markedly to about 40% of those without rifampicin. The findings suggest that rifampicin may increase the elimination of nifedipine, presumably by induction of its hepatic metabolism. Nisoldipine, another calcium antagonist, also failed to lower the patient's blood pressure, when given in combination with rifampicin. Taken together, these findings indicate that more caution should be urged when calcium antagonist is prescribed along with rifampicin.

ISSN:0002-9629    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Chronic fatigue syndrome (CFS) is a multi-faceted disorder for which no etiology has been determined. This paper discusses the implications of the new clinical case definition of CFS on previous and future studies of this illness. The authors' own management approach is also discussed.

ISSN:0002-9629    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:0002-9629    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Recent evidence suggests that the mechanism of insulin action depends in part on protein phosphorylation on tyrosine residues. A cascade of phosphorylation/dephosphorylation reactions is proposed to modulate multiple enzymes involved in metabolism, protein synthesis, and cell growth. Direct evidence is presented for the phosphorylation of myelin basic protein and microtubule-associated protein 2 on tyrosine residues by the insulin receptor.

ISSN:0002-9629    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

This article covers considerations in the etiology of various forms of precocious puberty and premature sexual development. The normal pubertal process with maturation of the hypothalamic pituitary gonadal axis is reviewed. The differential diagnosis of precocious puberty is discussed with particular emphasis on the difference between gonadotropin-dependent and gonadotropin-independent processes. Established therapies and newer medical treatments with their pathophysiologic rationale are considered in detail.

ISSN:0002-9629    

出版商:OVID    

年代:1992

数据来源: OVID