摘要:

ObjectiveTo determine whether the cholesterol distribution is impaired in erythrocyte membranes of normo- and hypercholesterolaemic patients with untreated essential hypertension.DesignObservational case-control study.MethodsErythrocytes were prepared from venous blood samples obtained from normotensive subjects and hypertensive patients. The membrane cholesterol distribution was measured by cholesterol oxidation to cholestenone after continuous cholesterol oxidase treatment. The membrane cholesterol content was determined. The ability of cells to be labelled with [3H]-cholesterol was also tested.ResultsThe cholesterol distribution was asymmetric in erythrocyte membranes of the control subjects and hypertensive patients. The oxidation rate was faster in normotensive subjects, and no differences were found between normo- and hypercholesterolaemic hypertensive patients. Total cholesterol mass was lower in erythrocyte membranes of hypertensive patients, as indicated by a higher incorporation of radioactive cholesterol.ConclusionThese data suggest that the membrane cholesterol distribution is impaired in patients with untreated essential hypertension, and support the presence of cholesterol-rich domains in the erythrocyte membrane inner monolayer.

ISSN:0263-6352    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo compare the incidence of cough in patients with a history of angiotensin converting enzyme (ACE) inhibitor-related cough who received losartan [a type 1 angiotensin II (Ang II) receptor antagonist], lisinopril (an ACE inhibitor) or hydrochlorothiazide (a diuretic).DesignAn international, multicentre, randomized, double-blind, parallel-group controlled trial.SettingOutpatient clinics at 20 tertiary care medical centres in 11 countries.PatientsOne hundred and thirty-five patients with uncomplicated primary hypertension with a history of ACE inhibitor-related cough were randomly assigned to the double-blind treatment phase and completed the study.InterventionAfter confirming that the cough was ACE inhibitor-related by a single-blind rechallenge, followed by a placebo washout period, patients were randomly assigned to receive 50 mg losartan, 20mg lisinopril or 25 mg hydrochlorothiazide once a day for 8 weeks.Main outcome measuresCough incidence, severity and frequency were assessed by a self-administered questionnaire and a visual analogue scale.ResultsThe percentage of patients who complained of cough was significantly higher with lisinopril than with losartan or hydrochlorothiazide. The mean visual analogue scale scores for patients treated with lisinopril demonstrated that these patients coughed more frequently than those who received losartan or hydrochlorothiazide.ConclusionThe incidence of cough related to the type 1 Ang II receptor antagonist losartan is significantly lower than that observed with lisinopril, and similar to that observed with hydrochlorothiazide in patients with a rechallenged ACE inhibitor cough. Type 1 Ang II receptor antagonists represent a potential new treatment for hypertensive patients in whom ACE inhibitors are indicated, but who develop a cough with these agents.

ISSN:0263-6352    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo explore the repercussion of cardiac denervation on the short-term blood pressure variability in humans, in order to assess the extent to which the variability of blood pressure is linked to the variability of heart rate.MethodsBeat-to-beat blood pressure and RR interval time were recorded in 16 heart-transplanted patients and were compared with those of 10 healthy control subjects in the resting supine, sitting and standing positions. Blood pressure and RR interval variabilities were assessed by spectral analysis.ResultsThe total blood pressure power and the supine and sitting very low-frequency, low-frequency and high-frequency blood pressure variability were similar in the heart-transplanted patients and in the controls, despite a marked reduction in the RR interval variability in the heart-transplanted patients. However, the heart-transplanted patients had lower standing low-frequency blood pressure variability than the control subjects. Moreover, very low-frequency and low-frequency RR interval variabilities reappeared in the long-term heart-transplanted patients but not in the short-term heart-transplanted patients (range of time after transplantation 53–124 and 3–25 months, respectively).ConclusionsShort-term RR interval fluctuations are not mandatory for the maintenance of normal blood pressure variability in the supine and sitting positions, but may contribute to the increase in the low-frequency blood pressure variability which occurs normally in the standing position. Moreover, the long-term heart-transplanted patients had increased RR interval variability, which may have been caused by the reappearance of limited autonomic cardiac modulation. However, this increased RR interval variability did not affect the corresponding blood pressure variability.

ISSN:0263-6352    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveAn increased incidence of cardiovascular accidents in the morning has been reported, but the reason why is not clear. We measured 24-h haemodynamics and focused on its change in the morning.DesignTo study the circadian variation of haemodynamics, we recorded 24-h direct blood pressure and electrocardiogram using a telemetry method, in 21 untreated inpatients with essential hypertension, and measured cardiac output using the dye-dilution method in the morning, in the evening and during sleep. We also determined the beat-to-beat cardiac output (using the pulse-contour method), the total peripheral resistance and the ratio of low- to high-frequency components (using power spectral analysis of the R-R interval during 24 h), and made comparisons between morning and evening values.ResultsBoth systolic and diastolic blood pressure increased rapidly in the early morning. Although the comparison of blood pressure between morning and evening showed no difference, total peripheral resistance and low- to high-frequency ratio were significantly higher in the morning than in the evening, but cardiac output was lower in the morning.ConclusionsSympathetic nervous activity and vascular resistance seem to be higher in the morning than in the evening, and these haemodynamic changes may stress the cardiovascular system.

ISSN:0263-6352    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo investigate the effect on blood pressure for 10-min compared with 40-min episodes of physical activity for 4 days.Design and methodsThe design used a randomized crossover trial of two exercise episode durations, involving 17 subjects, which were performed in a university setting. The intervention was exercise on a stationary bicycle for four consecutive days, at 50% of maximal oxygen uptake (determined by heart rate), for episode durations of 10 or 40min. A rest period of 10 days followed before exercise for the alternative duration was performed. The main outcome measure was blinded assessment of blood pressure 24 h after the last exercise episode.ResultsSignificant reductions were found in systolic and diastolic blood pressure after 4 days of 40 min but not after 4 days of 10 min stationary cycling. The reduction in blood pressure was significant for both systolic and diastolic blood pressure for 4 days of 40 min of exercise episodes.ConclusionExercise of moderate intensity on a stationary bicycle for 10 min for 4 days is not effective in lowering blood pressure in comparison with the same exercise for 40 min for 4 days. The experimental design employed in the present study has potential for monitoring the effects of exercise on blood pressure.

ISSN:0263-6352    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo assess reference values of ambulatory blood pressure in normotensive children.Subjects and designTwenty-four-hour non-invasive ambulatory blood pressure monitoring (ABPM) was carried out in 241 healthy normotensive children aged from 6 to 16 years (126 boys, mean ± SD age 11.2 ± 2.7 years; 115 girls, mean ± SD age 10.9 ± 2.9 years). The subjects were subdivided into three age-sex groups: 6–9, 10–12 and 13–16 years.SettingPrimary care.Main outcome measuresABPM was performed using an oscillometric device (SpaceLabs model 90207) and appropriate cuff size during a regular school day. Blood pressure was measured every 20 min from 0600 to 2400 h, and thereafter every 30min. At each monitoring session the following parameters were calculated for both systolic (SBP) and diastolic blood pressure (DBP): means and centiles for 24-h, daytime (0800–2200 h) and night-time (2400–0600 h); circadian variability, estimated as the blood pressure fall between the day and the night periods and the day: night ratio; and load, as the percentage of measurements above the age- and sex-specific 95th centile (P95).ResultsThe upper limits of 'normality' for the mean of 24-h SBP and DBP estimated as the P95in each age subgroup were 121/71 and 119/71 mmHg, 123/78 and 120/74 mmHg, and 124/78 and 125/75 mmHg, for boys and girls, respectively. A progressive increase in SBP with age was observed in both sexes, in contrast, DBP was similar throughout the age range. A nocturnal blood pressure fall of approximately 11 mmHg was observed for both SBP and DBP in all subgroups. The day: night ratio was 1.12 and 1.22 for SBP and DBP, respectively. The upper limit of blood pressure load, estimated as the P95in all children, was 39% for SBP and 26% for DBP. A significant positive correlation was observed between casual blood pressure and 24-h ambulatory blood pressure (SBP: r = 0.61, P < 0.0001; DBP: r = 0.31, P < 0.0001). In general, mean ambulatory blood pressure, during the 24-h or the daytime period, was higher than casual blood pressure for both SBP and DBP.ConclusionABPM is feasible in children, and the values obtained are useful as a departure point in establishing reference values.

ISSN:0263-6352    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundIn several studies hypertension has been shown to be associated with an increased incidence of non-insulin-dependent diabetes mellitus (NIDDM). This may be due to hypertension itself or to the deleterious effects of some antihypertensive agents on glucose tolerance and insulin sensitivity.MethodsWe examined the 3.5-year incidence of diabetes mellitus in relation to hypertension and antihypertensive medication in a population-based study of elderly subjects (n = 805) aged 65–74 years in Kuopio, Finland.ResultsOf the subjects studied, 60% had hypertension at baseline and 50% of the hypertensive subjects were on drug therapy at baseline. Hypertensive subjects had a significantly higher incidence of NIDDM than non-hypertensive subjects. However, after adjustment for age, body mass index, waist: hip ratio, sex, and fasting glucose and insulin levels, the increased risk of NIDDM in hypertensive subjects was no longer statistically significant. Subjects with high blood pressure (≥160/95 mmHg) at the baseline examination who were not taking β-blockers or diuretic medication had a 1.56-fold increased risk of developing NIDDM, whereas subjects with hypertension who were taking those agents had a 1.88-fold risk of developing NIDDM compared with subjects with normal blood pressure. The risk of developing NIDDM was accompanied by elevated fasting insulin levels. After adjustment for age, sex, body mass index, waist:hip ratio, and fasting glucose and insulin levels, hypertensive subjects taking diuretics or β-blockers, or both, still had a 1.56-fold increased risk of developing NIDDM relative to normotensive subjects. Hypertensive subjects taking diuretics or β-blockers, or both, had a significantly higher incidence of NIDDM than hypertensive subjects not on pharmacological therapy. However, after adjustment for 2-h glucose and insulin concentrations, the incidence of NIDDM did not differ between the hypertensive subjects.ConclusionThe data presented suggest that the increased risk of NIDDM in hypertensive subjects taking β-blockers or diuretics, or both, is explained at least partly by metabolic disturbances related to drug therapy.

ISSN:0263-6352    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Alms and methodsThe association between body mass index (BMI) and blood pressure is well known in relatively obese populations. The purpose of the present study was to investigate the relationship between BMI and blood pressure in a lean population. Through cluster sampling, individuals aged >30 years in 190 out of 154 082 districts were selected for study. Among 25 567 eligible individuals, measurements of blood pressure and BMI were made in 22 354.ResultsThe BMI for males was 22.8 ± 2.7kg/m2and for females was 23.4 ± 3.2 kg/m2(means ± SD). Over a BMI range from 16 to 31 kg/m2the relationships between BMI and systolic and diastolic blood pressure were almost linear. Over the BMI range 25–31 kg/m2(overweight-to-obese) each BMI unit was associated with a difference of 1.0 mmHg in diastolic blood pressure. Over the BMI range 16–25 kg/m2(normal-to-lean) each BMI unit was associated with a difference of 0.89 mmHg in diastolic blood pressure.ConclusionWe conclude that a strong association between BMI and blood pressure exists for lean as well as for obese subjects.

ISSN:0263-6352    

出版商:OVID    

年代:1994

数据来源: OVID