摘要:

Platelet free Ca2+concentration has been found to be elevated in essential hypertension and to correlate with blood pressure level. Free cytoplasmic calcium concentration is determined by calcium influx, pooling, and efflux. The present study found a Ca2+-ATPase in platelet membranes that has a high afflnity for Ca2+(Km∼-1 μM), is inhibited by low concentrations of orthovanadate (K1— 1 μM), and can be stimulated by calmodulin (Km∼ — 5 nM). The absolute increase in calmodulin-stimulated Ca2+-ATPase activity was not different between normotensive and hypertensive subjects; however, the degree of stimulation of Ca2+-ATPase activity at saturating calmodulin concentrations apparently was diminished in calmodulindeficient membranes from subjects with established essenltial hypertension (40%) as compared to that in normotensive subjects of similar age (135%;p< 0.001). Aflinities for calmodulin and Ca2+were comparable between the two groups, while the capacity for Ca2+-ATPase activity (basal and calmadulin-stimulated) was markedly greater (1.5- to 1.8-fold) in both native and calmodulin-deficient membranes from hypertensive subjects. On the other hand, the defective calcium efflux pump activity, as Bssessed by a decreased degree of calmodulin stimulation, may have contributed to elevated cytoplasmic calcium concentrations and the associated enhanced hormone sensitivity in platelets from essential hypertensive subjects. This may represent an adaptive negative feedback control mechanism to protect the cell against Ca2+overload.

ISSN:0194-911X    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Ketanserin, an antagonist highly selective for 5-hydroxytryptamine (serotonin) type 2 (S2) receptors, was given as monotherapy in a dose of 40 mg b.i.d. to 24 subjects with mild to moderate essential hypertension. Its effects were evaluated in a placebo-controlled double-blind crossover study. The effect on blood pressure in 18 subjects was monitored by 24-hour ambulatory intra-arterial measurements. Systolic and diastolic intra-arterial pressures were significantly lowered by ketanserin both during the day and at night, whereas heart rate was unchanged. Cuff pressure readings (triplicate measurements) with the London School of Hygiene sphygmomanometer and an automatic device (12 measurements In 1 hour) in the outpatient clinic also showed a significant effect on both supine and standing pressures. No postural hypotension was noted. Ketanserin had no effect on endogenous creatinine clearance, serum cholesterol levels, and the plasma levels of norepinephrine, renin, and aldmterone. The only side effect that was significantly more common with ketanserin than with placebo treatment was an increase in body weight. Ketanserin may have a place in the treatment of mild to moderate essential hypertension.

ISSN:0194-911X    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

We report an unusual association of hyperkalemia, mild hyperchloremic acidosis, and hypertension in a young woman. Pseudohyperkalemia, Addison's disease, renal insufficiency, classical hyporeninemic hypoaldosteronism, isolated hypoaldosteronism, and iatrogenic causes were excluded. The patient's findings were compatible with a rare syndrome designated as type II pseudohypoaldosteronism, Gordon's syndrome.

ISSN:0194-911X    

出版商:OVID    

年代:1986

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:1986

数据来源: OVID