Effect of hypotension on the arterial system responsiveness

The correlation analysis revealed no correlation within the range 110 to 80 mm Hg further transforming into a direct (within the range lower than 80 mm Hg) dependence of the pressure responses to mesatone on the reduction of initial mean arterial pressure under orthostatic hypotension in anaesthetised rats. Under paraverine hypotension a reverse correlation within the range 110-80 mm Hg transforming into a direct dependence (within the range lower than 80 mm Hg) of the responses to mesatone were observed. The dependence of cardiac shifts to mesatone on the initial arterial pressure was not occurred. The mechanisms of dependence of the systemic vascular responses on initial tone of arterial vessels, are discussed.     

Effect of initial (spontaneous) arterial pressure on systemic hemodynamic orthostatic responses

In anesthetized rats, a reverse linear correlation of arterial pressure (AP) shifts was found within the range of initial AP over 95 mm Hg under the head-up tilts at 30 and 45 degrees. Within the range beneath 95 mm Hg this correlation was transformed into the direct one. Under 60 degrees tilt such correlation only occurred within the range beneath 95 mm Hg. The direction and degree of the arterial system responsiveness seems to depend on the tilt value as well as on the range of the initial AP.     

The initial tone of arteries determines the magnitude of depressor responses caused by nitroglycerin

The correlation analysis revealed a direct (within the range 80 to 120 mm Hg) further transforming into a reverse (within the range 121 to 160 mm Hg) dependence of the blood pressure depressor shifts on the initial mean arterial pressure in anaesthetised rats. Within the physiological range of arterial pressure (70 to 130 mm Hg) there is no difference in responses to nitro-glycerine from their initial values. The mechanisms of dependence of the systemic vascular responses on initial tone of arterial vessels, are discussed.     

Effects of lower body positive pressure on muscle sympathetic nerve activity response [correction of respopnse] to head-up tilt

The benefits of lower body positive pressure (LBPP) are generally accepted for clinical treatment in medical emergencies caused by massive bleeding to maintain the systemic blood pressure. They are also used by NASA post spaceflight for preventing orthostatic hypotension in the astronauts. However, controversy still exists concerning the mechanisms underlying LBPP benefits. The purpose of this study was to test the hypothesis that the baroreflex-mediated enhancement in sympathetic activity would be attenuated by LBPP during an orthostatic challenge in humans. Specifically, we studied 1) the sympathetic activity responses by the microneurographic technique, using direct intraneural measurement of muscle sympathetic nerve activity (MSNA); and 2) the contributions of preload and afterload to the chances in MSNA response during orthostasis on application of LBPP. To accomplish these issues, MSNA was recorded microneurographically along with noninvasive measurement of the cardiovascular variables in all the subjects during exposure to a 70 degrees HUT with 30-mm Hg LBPP.     

Relaxation therapy and continuous ambulatory blood pressure in mild hypertension: a controlled study.

OBJECTIVE--To determine the long term effects of relaxation therapy on 24 hour ambulatory intra-arterial blood pressure in patients with mild untreated and uncomplicated hypertension. DESIGN--Four week screening period followed by randomisation to receive either relaxation therapy or non-specific counselling for one year. Ambulatory intra-arterial blood pressure was measured before and after treatment. SETTING--Outpatient clinic in Amsterdam''s university hospital. SUBJECTS--35 Subjects aged 20-60 who were being treated by general practitioners for hypertension but were referred to take part in the study. At three consecutive screening visits all subjects had a diastolic blood pressure without treatment of 95-110 mm Hg. Subjects were excluded if they had damaged target organs, secondary hypertension, diabetes mellitus, a cholesterol concentration greater than 8 mmol/l, or a history of malignant hypertension. INTERVENTIONS--The group allocated to relaxation therapy was trained for eight weeks (one hour a week) in muscle relaxation, yoga exercises, and stress management and continued exercising twice daily for one year with monthly visits to the clinic. The control group had the same attendance schedule but had no training and were requested just to sit and relax twice a day. All subjects were asked not to change their diet or physical activity. MAIN OUTCOME MEASURE--Changes in ambulatory intra-arterial blood pressure after one year of relaxation therapy or non-specific counselling. RESULTS--Mean urinary sodium excretion, serum concentration of cholesterol, and body weight did not change in either group. Diastolic pressures measured by sphygmomanometry were 2 and 3 mm Hg lower in subjects in the relaxation group and control group respectively at the one year follow up compared with initial readings. The mean diastolic ambulatory intra-arterial pressure during the daytime had not changed after one year in either group, but small treatment effects could not be excluded: the mean change for the relaxation group was -1 mm Hg (95% confidence interval -6 to 3.9 mm Hg) and for the control group -0.4 mm Hg (-5.3 to 4.6 mm Hg). Mean ambulatory pressure in the evening also had not changed over the year, and in both groups nighttime pressure was 5 mm Hg higher. The variability in blood pressure was the same at both measurements. CONCLUSIONS--Relaxation therapy was an ineffective method of lowering 24 hour blood pressure, being no more beneficial than non-specific advice, support, and reassurance--themselves ineffective as a treatment for hypertension.     

Plasma prolactin responses to acute changes in central blood volume in man

The present study examined the relationship between plasma prolactin (PRL) and central blood volume (CBV) in man. 6 adult males lay in a lower body pressure box at a thermoneutral ambient temperature (27 degrees C) on three occasions. On each occasion a 70-min control period was followed by a 20-min exposure to a lower body pressure of either 0 mm Hg, -20 (lower body negative pressure; LBNP), or +10 mm Hg (lower body positive pressure; LBPP), followed by a 60-min recovery period. Blood was drawn and urine collected at 30-min intervals. Blood pressure and heart rate were monitored at 30-min intervals during control and recovery periods and at 10-min intervals during lower body pressure exposure. Neither 0 mm Hg, LBNP, nor LBPP altered plasma osmolality, sodium, or potassium levels. Increasing CBV by LBPP increased systemic blood pressure (p less than 0.01) but had no effect on heart rate, plasma PRL, or urine osmolality. LBNP, in contrast, increased heart rate (p less than 0.05). Half of the subjects undergoing LBNP developed presyncopal symptoms, characteristic of a vasovagal reaction which includes precipitous hypotension. Subjects developing these symptoms tended to exhibit an increase in plasma PRL and an increase in urine osmolality. Asymptomatic subjects demonstrated no change in plasma PRL or urine osmolality. In addition, subjects exhibiting a PRL response to LBNP had a higher control period plasma PRL baseline (231%) than did asymptomatic subjects. These data suggest that while plasma PRL levels are not sensitive to nonhypotensive changes in CBV, they do respond to hypotensive decreases in CBV and/or its associated nausea.(ABSTRACT TRUNCATED AT 250 WORDS)     

Factors affecting cold-induced hypertension in rats

A 3- to 4-week exposure of rats to a cold environment (5 +/- 2 degrees C) induces hypertension, including elevation of systolic, diastolic, and mean blood pressures and cardiac (left ventricular) hypertrophy. The studies described here were designed to investigate some factors affecting both the magnitude and the time course for development of cold-induced hypertension. The objective of the first study was to determine whether there was an ambient temperature at which the cold-induced elevation of blood pressure did not occur. The objective of the second experiment was to determine whether body weight at the time of exposure to cold affected the magnitude and time course for development of hypertension. To assess the first objective, male rats were housed in a chamber whose temperature was maintained at 5 +/- 2 degrees C while others were housed in an identical chamber at 9 +/- 2 degrees C. After 7 days of exposure to cold, the rats exposed to the colder temperature had a significant elevation of blood pressure (140 +/- 2 mm Hg) compared with the group maintained at 9 degrees C (122 +/- 3 mm Hg). The rats exposed to 9 degrees C had no significant elevation of systolic blood pressure at either 27 or 40 days after initiation of exposure to cold. At the latter time, the temperature in the second chamber was reduced to 5 +/- 2 degrees C. By the 25th day of exposure to this ambient temperature, the rats had a significant increase in systolic blood pressure above their levels at 9 degrees C. Thus, there appears to be a threshold ambient temperature for elevation of blood pressure during exposure to cold. That temperature appears to lie somewhere between 5 and 9 degrees C. The second objective was assessed by placing rats varying in weight from approximately 250 to 430 g in air at 5 degrees C. There was a highly significant direct relationship (r = 0.96) between body weight at the time of introduction to cold and the number of days required to increase systolic blood pressure by 10 mm Hg above pre-cold exposure level. The third objective was to make an initial assessment of potential differences among strains of rats with respect to development of cold-induced hypertension. To this end, rats of the Fischer 344 strain were used. Systolic blood pressures of these rats also increased during chronic exposure to cold.(ABSTRACT TRUNCATED AT 400 WORDS)     

Blood pressure control by home monitoring: meta-analysis of randomised trials

Objective To determine the effect of home blood pressure monitoring on blood pressure levels and proportion of people with essential hypertension achieving targets.Design Meta-analysis of 18 randomised controlled trials.Participants 1359 people with essential hypertension allocated to home blood pressure monitoring and 1355 allocated to the “control” group seen in the healthcare system for 2-36 months.Main outcome measures Differences in systolic (13 studies), diastolic (16 studies), or mean (3 studies) blood pressures, and proportion of patients achieving targets (6 studies), between intervention and control groups.Results Systolic blood pressure was lower in people with hypertension who had home blood pressure monitoring than in those who had standard blood pressure monitoring in the healthcare system (standardised mean difference 4.2 (95% confidence interval 1.5 to 6.9) mm Hg), diastolic blood pressure was lower by 2.4 (1.2 to 3.5) mm Hg, and mean blood pressure was lower by 4.4 (2.0 to 6.8) mm Hg. The relative risk of blood pressure above predetermined targets was lower in people with home blood pressure monitoring (risk ratio 0.90, 0.80 to 1.00). When publication bias was allowed for, the differences were attenuated: 2.2 (-0.9 to 5.3) mm Hg for systolic blood pressure and 1.9 (0.6 to 3.2) mm Hg for diastolic blood pressure.Conclusions Blood pressure control in people with hypertension (assessed in the clinic) and the proportion achieving targets are increased when home blood pressure monitoring is used rather than standard blood pressure monitoring in the healthcare system. The reasons for this are not clear. The difference in blood pressure control between the two methods is small but likely to contribute to an important reduction in vascular complications in the hypertensive population.     

Long-term follow-up of a hypertension screening program.

Of 185 people found to be hypertensive in a shopping centre screening program who went to their physician and had medication prescribed, then were contacted 18 months later, 33 had discontinued the medication at their physician''s request. But of 152 who were to continue taking medication 139 (91.4%) had complied. Blood pressure had decreased to less than 160 mm Hg systolic or less than 95 mm Hg diastolic, or both, in 65.1% of the 152; was 160 to 169 mm Hg systolic or 95 to 99 mm Hg diastolic, or both, in 13.8%; was mildly or moderately decreased but still above 169 mm Hg systolic or 99 mmHg diastolic, or both, in 8.6%; and was higher than before the onset of treatment in 3.9%. Adequacy of blood pressure control was not related to age, sex, initial blood pressure values, awareness before the screening of having hypertension, or treatment for hypertension before the screening. Diuretics had been prescribed for 93.5% of the 139 patients, most often as single-pill combinations with other antihypertensive agents.     

Three year follow up of patients with raised blood pressure identified at health checks in general practice.

OBJECTIVE--To assess the extent of three year follow up of blood pressure, weight, and smoking habit in patients with raised blood pressure identified at health checks. DESIGN--Retrospective audit of medical and nursing records. SETTING--Three general practices in Oxfordshire. PATIENTS--386 of 448 patients with raised blood pressure (diastolic greater than or equal to 90 or systolic greater than or equal to 160 mm Hg) identified from 2935 patients aged 35-64 attending health checks in 1982-4. MEASUREMENTS and MAIN RESULTS--All records of blood pressure, weight, and smoking habit in the medical record were abstracted for three years after the initial health check. All 42 patients with an initial diastolic blood pressure greater than or equal to 105 mm Hg and 316 of 344 patients with an initial pressure of 90-104 mm Hg had at least one further measurement of their blood pressure. Follow up of smoking habit and of weight was less complete with only half of the 100 smokers and 67 of the 87 obese patients (body mass index greater than or equal to 30) having any documented follow up of these risk factors. Annual follow up in the second and third years occurred in 228/297 (76.8%) and 232/320 (72.5%) in patients with blood pressure greater than 95 mm Hg at the beginning of each year. For patients who smoked annual follow up in these years occurred in fewer than a third and for those who were obese in just over half. On the assumption that those not followed up had not changed, at the end of three years the proportion of patients with diastolic blood pressure greater than or equal to 100 mm Hg had fallen from 61 patients (15.8%) to 31 (8.1%); the proportion of smokers had fallen from 103 (26.7%) to 94 (24.4%); and the proportion of obese patients had fallen from 87 (22.5%) to 79 (20.5%). CONCLUSIONS--These changes were modest and in the absence of a control group cannot be attributed necessarily to health checks. Although the standard of follow up was better than in previously reported studies of the management of hypertension, the results emphasise the need to develop formal protocols for dietary and antismoking interventions and to evaluate formally the effectiveness (and cost effectiveness) of health checks.     

Control of blood pressure and risk of first acute myocardial infarction: Skaraborg hypertension project.

OBJECTIVE--To analyse the relation between treated blood pressure and concomitant risk factor and morbidity from acute myocardial infarction. DESIGN--Prospective longitudinal study. Treated blood pressures and other variables were used to predict acute myocardial infarction. SETTING--Primary health care in Skaraborg, Sweden. SUBJECTS--1121 men and 1453 women aged 40-69 years at registration at outpatient clinics, 1977-81, with no evidence of previous myocardial infarction were followed up for an average of 7.4 years. Subjects were undergoing treatment with drugs to lower blood pressure or had blood pressure that exceeded the systolic or diastolic limits, or both, for diagnosis (> 170/> 105 mm Hg (patients aged 40-60 years) and > 180/> 110 mm Hg (older than 60 years)) on three different occasions, or both. MAIN OUTCOME MEASURES--First validated event of fatal or non-fatal acute myocardial infarction. RESULTS--In men but not in women there was a negative relation between treated diastolic blood pressure and risk of acute myocardial infarction. Left ventricular hypertrophy and smoking were contributory risk factors in both sexes, as was serum cholesterol concentration in men. In men with normal electrocardiograms (n = 345) risk increased with increasing diastolic blood pressure (P = 0.047), whereas the opposite was found in men with electrocardiograms suggesting ischaemia or hypertrophy, or both (n = 499, P = 0.009). In those with a reading of 95-99 mm Hg the relative risk was 0.30 (P = 0.034); at > or = 100 mm Hg it was 0.37 (P = 0.027). No similar relations were seen in women or for systolic blood pressure. CONCLUSION--It may be hazardous to lower diastolic blood pressure below 95 mm Hg in hypertensive men with possible ischaemia or hypertrophy, or both. Electrocardiographic findings should be considered when treatment goals are decided for men with hypertension.     

Sodium and potassium intake and blood pressure change in childhood.

OBJECTIVE--To assess the association between sodium and potassium intake and the rise in blood pressure in childhood. DESIGN--Longitudinal study of a cohort of children with annual measurements during an average follow up period of seven years. SETTING--Epidemiological survey of the population of a suburban town in western Netherlands. SUBJECTS--Cohort of 233 children aged 5-17 drawn at random from participants in the population survey. MAIN OUTCOME MEASURES--At least six annual timed overnight urine samples were obtained. The mean 24 hour sodium and potassium excretion during the follow up period was estimated for each participant and the sodium to potassium ratio calculated. Individual slopes of blood pressure over time were calculated by linear regression analysis. RESULTS--No significant association was observed between sodium excretion and the change in blood pressure over time. The mean systolic blood pressure slopes, however, were lower when potassium intake was higher (coefficient of linear regression -0.045 mm Hg/year/mmol; 95% confidence interval -0.069 to -0.020), and the change in systolic pressure was greater when the urinary sodium to potassium ratio was higher (0.356 mm Hg/year/unit; 95% confidence interval 0.069 to 0.642). In relation to potassium this was interpreted as a rise in blood pressure that was on average 1.0 mm Hg (95% confidence interval -1.65 to -0.35) lower in children in the upper part of the distribution of intake compared with those in the lower part. The mean yearly rise in systolic blood pressure for the group as a whole was 1.95 mm Hg. Urinary electrolyte excretion was not associated with diastolic blood pressure. CONCLUSION--Dietary potassium and the dietary sodium to potassium ratio are related to the rise in blood pressure in childhood and may be important in the early pathogenesis of primary hypertension.     

Cardiovascular responses to catecholamines at 12 degrees C in the American bullfrog (Rana catesbeiana)

The effects of epinephrine, norepinephrine, phenylephrine, and isoproterenol on blood pressure and heart rate were studied in cannulated American bullfrogs, Rana catesbeiana. The bullfrogs were chronically cannulated with a T cannula in the right sciatic artery. In warm-acclimated (22 degrees C) bullfrogs, preinjection mean systemic arterial pressure (SAP) prior to experimental treatment was 13.1 +/- 0.7 mm Hg. Preinjection heart rate was 34.8 +/- 1.8 beats per minute. These parameters were lower in cold-acclimated (12 degrees C) bullfrogs. Cold-acclimated animals had mean SAP values of 8.2 +/- 0.3 mm Hg, and heart rate was 11.1 +/- 1.1 beats per minute. Epinephrine, norepinephrine, and phenylephrine increased blood pressure to an equivalent degree in warm- and cold-acclimated animals. Dose-related decreases in heart rate in response to these catecholamines were observed in warm- but not in cold-acclimated bullfrogs. Warm-acclimated animals were more responsive to isoproterenol from 0.03 micrograms/kg body weight (bw) to 10 micrograms/kg bw than were cold-acclimated animals. The response to isoproterenol was effectively blocked by propranolol (5 mg/kg bw) in both warm- and cold-acclimated animals. Propranolol alone decreased mean SAP in both warm- and cold-acclimated animals, suggesting blockade of endogenous sympathetic activity. Beta receptor response thus appears diminished, but not absent at 12 degrees C. However, the alpha receptors responsible for elevation of blood pressure equally responsive at 12 degrees and 22 degrees C.     

Management of raised blood pressure in New Zealand: a discussion document.

A report to the National Advisory Committee on Core Health and Disability Support Services, New Zealand, on the management of raised blood pressure recommends that decisions to treat raised blood pressure should be based primarily on the estimated absolute risk of cardiovascular disease rather than on blood pressure alone. In general, patients with a blood pressure of 150-170 mm Hg systolic or 90-100 mm Hg diastolic, or both, should be given treatment to lower blood pressure if the risk of a major cardiovascular disease event in 10 years is more than about 20%. The results of clinical trials indicate that, at this level of absolute risk, 150 people would require treatment to reduce the annual number of cardiovascular events by about one. Implementation of these recommendations may result in a smaller proportion of people aged under 60, particularly women, receiving treatment but an increased proportion of older people treated. In the absence of specific contraindications, low dose diuretics and low dose beta blockers should be considered for first line treatment, since for only these drug groups is there direct evidence of reduced risk of stroke and coronary disease in people with raised blood pressure.     

Dependence of arterial pressure and cardiac output on initial (regulated) arterial tone during beta-adrenoreceptor stimulation in rats

A significant decrease of arterial pressure in response to isoproterenol occurred in anaesthetised rats with the initial pressure 101-130 mm Hg. Elevation of the initial pressure up to 131-180 mm Hg led to a significant attenuation of the depressor effect. The correlation analysis revealed transformation of direct correlation into inverse one between the depressor responses to isoproterenol and the degree of elevation of the initial arterial tone, as well as lack of such a dependence in the cardiac output shifts.     

Macroproteinemia and the prognostic assessment of blood loss

The dependence of blood loss quantitative indices (duration, number and volume of exfusions) on the initial state of the blood protein system was studied in experiments with dogs. The true correlation was found between the macroprotein contents in plasma and the duration of the arterial pressure compensation phase at the level of 5.3 kPa (40 mm Hg). Hypermacroproteinemia is evident of low organism stability (resistance) and is an unfavourable prognostic characteristic in experimental blood loss.     

Comparative physiological responses of normotensive and essentially hypertensive men to exercise in the heat

Six essentially hypertensive men (average resting arterial pressure of 150/97 mm Hg) and eight normotensive controls (average resting arterial pressure of 115/73 mm Hg) were tested during 1 h of dynamic leg exercise in a warm environment. The groups were well matched for age, VO2 max, body surface area, weight, and body fat. Environmental conditions were 38 degrees C dry-bulb, 28 degrees C wet-bulb; exercise intensity was approximately 40% VO2 max (85-90 W). There were no significant intergroup differences in core or mean skin temperatures, calculated heat exchange variables, heart, or sweat rates. Blood pressure differences between the groups were maintained (P less than 0.01). The hypertensive group responded with a significantly lower stroke index (P less than 0.01) and cardiac index (P less than 0.01), and a decreased slope of the rise in forearm blood flow (P less than 0.01) due to an higher vascular resistance (P less than 0.01). The combined heat load (M + R + C) presented was not sufficient to override the hypertensives' higher cutaneous vasoconstrictor tone. However, on a practical basis, the hypertensives were able to tolerate exercise in the heat as well as their normotensive counterparts.     

Antihypertensive effect of diet compared with drug treatment in obese men with mild hypertension.

OBJECTIVE--To determine whether dietary treatment has a similar antihypertensive effect to conventional drug treatment while being superior to drugs in improving serum lipid concentrations in obese men with mild hypertension. DESIGN--Six week run in period followed by randomisation to either diet or drug treatment groups for one year. SETTING--Outpatient clinic in city hospital. PATIENTS--61 Men aged 40-69 years, body mass index greater than or equal to 26, diastolic blood pressure 90-104 mm Hg when untreated. Exclusion criteria were signs of organ damage secondary to hypertension and diseases that might have interfered with compliance or with interpretation of results. INTERVENTIONS--Dietary treatment was based on weight reduction, restriction of sodium, and decrease of excess alcohol intake (defined as greater than or equal to 250 g alcohol per week). Drug treatment used a stepped care approach with atenolol as drug of first choice. MAIN OUTCOME MEASURES--Diastolic blood pressure less than 90 mm Hg; absolute reductions in blood pressure and serum lipid concentrations. RESULTS--Mean body weight decreased 7.6 kg in the diet group and increased 0.9 kg in the drug treatment group (p less than 0.0001), and mean sodium excretion decreased 42 and 10 mmol/24 h respectively (p = 0.019). There was no difference in reported alcohol intake. Mean systolic blood pressure decreased 4 mm Hg in the diet group and 16 mm Hg in the drug group (p = 0.003) and diastolic blood pressure 3 and 11 mm Hg respectively (p = 0.002). Diastolic blood pressure of 90 mm Hg was attained by 29% of the diet group (nine men) and 73% (22) of those receiving drug treatment (mean difference 44%, 95% confidence interval 21 to 67%, p = 0.001). Dietary treatment produced decreases in mean serum concentrations of total and low density lipoprotein cholesterol as well as triglycerides and an increase in high density lipoprotein cholesterol concentration. In the drug treatment group the changes were in the opposite direction, and the groups differed significantly in all but total cholesterol. CONCLUSIONS--Dietary treatment was inferior to conventional drug treatment in controlling mild hypertension but superior in lowering serum concentrations of lipids.     

Risk Factors of Cardiovascular Diseases and the Capillary Endothelium in Subjects with Different Levels of Normal Blood Pressure

The capillary circulation in the forearm and crus was studied by occlusion plethysmography at rest and upon stimulation with nitric oxide during reactive hyperemia in 249 virtually healthy subjects with different levels of arterial blood pressure lower than 140/90 mm Hg. Specific features of the microcirculation were found in the forearm and crus depending on the blood pressure level. An increase in the blood pressure higher than 120/80 mm Hg was associated with an increased adverse effect of integral risk factors and heredity on parameters of the capillary circulation, especially in women.     

Low-density lipoprotein receptor-related protein 5 variant A1330V is a determinant of blood pressure in Japanese males

We examined the influence of the A1330V variant in the low-density lipoprotein receptor-related protein 5 gene on blood pressure in a large cohort of Japanese workers. This study used analysis of covariance in a multivariate general linear model to adjust for other potential factors such as age, body mass index, blood chemistry and lifestyle. The target subjects were 1440 males and 1169 females selected from 3834 male and 2591 female workers in a single company. Hypertension was defined as systolic blood pressure >or=140 mm Hg and/or diastolic blood pressure >or=90 mm Hg or the use of antihypertensive medications. Genotype distributions for A1330V in hypertensive males (AA=139(54.5%), AV=101(39.6%), VV=15(5.9%)) and females (AA=48(63.2%), AV=24(31.6%), VV=4(5.3%)) were not significantly different from normotensive males (AA=594(50.1%), AV=488(41.2%), VV=103(8.7%)) and females (AA=568(52.0%), AV=441(40.3%), VV=84(7.7%)). Allele distributions were not significantly different in either sex. In males, analysis of covariance showed that the VV genotype was associated with a 2.5 mm Hg lower diastolic blood pressure and a 2.3 mm Hg lower mean blood pressure than the AA genotype. This study indicates that the 1330V allele is an independent factor for lower diastolic and mean blood pressure in Japanese males.