摘要:

The purpose of the present study was to evaluate whether the difference between blood pressure measured in the clinic or physician's office and the average daytime blood pressure accurately reflects the blood pressure response of the patient to the physician ("white coat effect" or "white coat hypertension"). We studied 28 hypertensive outpatients (mean age, 41.8 +/- 11.2 years; age range, 21 to 64 years) of 35 consecutive patients attending our hypertension clinic, in whom (1) continuous noninvasive finger blood pressure was recorded before and during the visit, (2) blood pressure was measured according to the Riva-Rocci-Korotkoff method (mercury sphygmomanometer) with the patient in the supine position, and (3) daytime ambulatory blood pressure was monitored with a SpaceLabs 90207 device. The peak blood pressure increase recorded directly during the visit was compared with the difference between clinic and daytime average ambulatory blood pressures. Compared with previsit values, peak increases in finger systolic and diastolic blood pressures during the visit to the clinic were 38.2 +/- 3.1 and 20.7 +/- 1.6 mm Hg, respectively (mean +/- SEM, P<.01 for both). Daytime average systolic and diastolic blood pressures were 135.5 +/- 2.5 and 89.2 +/- 1.9 mm Hg, with both lower than the corresponding clinic blood pressure values (146.6 +/- 3.6 and 94.9 +/- 2.2 mm Hg, P<.01). These differences, however, were <30% of the peak finger blood pressure increases during the physician's visit, to which these increases showed no relation. Although the visit to the physician's office was associated with tachycardia (9.0 +/- 1.6 bpm, P<.01), there was no difference between clinic and daytime average heart rates. These data indicate that the clinic-daytime average blood pressure difference does not reflect the alerting reaction and the pressure response elicited by the physician's visit and thus is not a reliable measure of the white coat effect. (Hypertension. 1998;31:1185-1189.)

ISSN:0194-911X    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Black hypertensive persons have been observed to have a greater degree of left ventricular hypertrophy than white hypertensives. However, previous studies have matched groups for blood pressure (BP) measured in the clinic, and it has been demonstrated that black hypertensives have an attenuated nocturnal BP dip. Clinic BPs may thus underestimate mean 24-hour BP in this group. To investigate whether the differences in left ventricular hypertrophy can be accounted for by the greater mean 24-hour BP in black hypertensives, 92 previously untreated hypertensives were studied with 24-hour ambulatory BP monitoring and echocardiography. The 46 black hypertensives (24 men and 22 women) were matched with the 46 white hypertensives for age, gender, and mean 24-hour BP. Despite similar mean 24-hour BPs (blacks, 142/93 mm Hg; whites, 145/92 mm Hg; P=.53/.66), the black group had a smaller mean nocturnal dip than the white group (blacks, 8/8 mm Hg; whites, 16/13 mm Hg; P<.01). In addition, mean left ventricular mass index (LVMI) was greater (blacks, 130 g/m2; whites, 107 g/m2; P<.001). Mean 24-hour systolic BP was significantly related to LVMI in both groups (blacks, r=.45, P<.01; whites, r=.56, P<.01). However, systolic BP dip correlated inversely with LVMI only in the black group (blacks, r=-.30, P<.04; whites, r=.05, P=.76). In a multiple regression model, LVMI was independently related to both mean daytime BP and mean nocturnal BP dip in black subjects but only to mean daytime BP in white subjects. In conclusion, the increased left ventricular hypertrophy observed in black hypertensives compared with white hypertensives is not accounted for by differences in mean 24-hour BP. However, LVMI in black hypertensives appears to be more dependent on nocturnal BP than that in white hypertensives; this, coupled with the attenuated BP dip in black hypertensives, suggests that the BP profile rather than 24-hour BP may be important in determining the differences in left ventricular hypertrophy. (Hypertension. 1998;31:1190-1194.)

ISSN:0194-911X    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Effects of a novel dihydropyridine type of antihypertensive drug, cilnidipine, on the regulation of the catecholamine secretion closely linked to the intracellular Ca2+were examined using nerve growth factor (NGF)-differentiated rat pheochromocytoma PC12 cells. By measuring catecholamine secretion with high-performance liquid chromatography coupled with an electrochemical detector, we showed that high K+stimulation evoked dopamine release from PC12 cells both before and after NGF treatments. Cilnidipine depressed dopamine release both from NGF-treated and untreated PC12 cells in a concentration-dependent manner. In contrast, inhibition by nifedipine was markedly decreased in the differentiated PC12 cells. With intracellular Ca2+concentration ([Ca2+]i) measurements using fura 2, the elevation of high K+-evoked[Ca2+]iwas separated into nifedipine-sensitive and -resistant components. The nifedipine-resistant [Ca2+]iincrease was also blocked by cilnidipine, as well as omega-conotoxin-GVIA. By the use of the conventional whole-cell patch-clamp technique, the compositions of the high-voltage-activated Ca2+channel currents in the NGF-treated PC12 cells were divided into types: L-type, N-type, and residual current components. It was also estimated that cilnidipine at 1 and 3 [micro sign]mol/L strongly blocked the N-type current without affecting the residual current. These results suggest that cilnidipine inhibits catecholamine secretion from differentiated PC12 cells by blocking Ca2+influx through the N-type Ca2+channel, in addition to its well-known action on the L-type Ca2+channel. (Hypertension. 1998;31:1195-1199.)

ISSN:0194-911X    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:1998

数据来源: OVID