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Biomedical subjects

J I Drayer

Publications and source records attributed to J I Drayer.

At least 37 records · Page 2Linked to original sources
PubMed1985

Definition of normalcy in whole-day ambulatory blood pressure monitoring.

In this study we have performed 24-hour ambulatory blood pressure monitorings in age-matched normotensive and hypertensive male subjects. The data have been analyzed in an attempt to define standards for the clinical use of ambulatory blood pressure monitoring in the diagnosis of hypertension. The data were analyzed with respect to possible differences in the averages of the whole-day, daytime and nighttime blood pressures, and differences in the prevalence of abnormal blood pressures between the two groups. A considerable overlap was found between the two groups with respect to the various blood pressure averages. The overlap in blood pressures occurred in fewer patients for diastolic than for systolic blood pressure, and less often when nighttime pressures were considered. Hypertensive men showed on average a greater incidence of abnormal blood pressures than normotensive subjects. However, nine of the normotensive control subjects showed more than 25 percent of abnormal readings of systolic or diastolic blood pressures during a 24-hour recording period. In contrast, fewer than 25 percent of abnormal blood pressure readings were found in 9 of the hypertensive patients. The data reported here may help to better define the use of ambulatory blood pressure monitoring techniques in the diagnosis of hypertension.

Adult↗
PubMed1985

Reproducibility of blood pressure values in normotensive subjects.

The reproducibility of whole-day blood pressure (BP) averages was evaluated in 56 normal volunteers. Blood pressure was monitored using a non-invasive automatic device that measured BP at 7.5 minute intervals for a 24h period. The whole-day systolic BP averages were closely similar on the two study days, 119 +/- 10 (S.D) and 117 +/- 11 mm Hg. A difference between the two whole-day averages of systolic blood pressure of greater than 10 mm Hg was found in 10 subjects. Values for the diastolic BP averages were 75 +/- 7 and 73 +/- 8 mm Hg with differences of greater than 5 mm Hg found in 15 subjects. Strong consistency of BP averages during the separate study days was also found for shorter monitoring periods: the 2h period (8 AM to 10 AM), the daytime period (6AM to 10PM) and the nighttime period (10PM to 6AM). Thus, blood pressure values obtained using a non-invasive ambulatory monitoring device are reproducible in the majority of normotensive control subjects.

Adult↗
PubMed1985

Whole-day BP monitoring in ambulatory normotensive men.

Noninvasive automated ambulatory BP monitoring techniques were used to evaluate BP patterns in 34 healthy normotensive men. Daytime BPs (128 +/- 12/80 +/- 7 mm Hg) were significantly higher and nighttime BP averages (109 +/- 11/67 +/- 9 mm Hg) were significantly lower than the casual BPs (119 +/- 13/76 +/- 9 mm Hg) of the subjects studied. On the average, 15.6% of the readings in each tracing showed systolic BPs above 140 mm Hg, and more than 25% of these elevated readings were found in six of the 34 subjects. The average incidence of elevated diastolic BPs (greater than 90 mm Hg) observed during each monitoring period was 14.4%, but six subjects had incidences of more than 25%. The incidence of elevated BP readings was not age related. However, subjects with a family history of hypertension generally had more elevated systolic BPs than those with no family history of hypertension (24% v 9%).

Adult↗
PubMed1984

Central and peripheral blockade of the sympathetic nervous system.

Agents that work primarily by inhibiting effects of the sympathetic nervous system continue to be widely used for the therapy of hypertension. There are two principal types of drugs: those that work in the central nervous system, and those that act primarily at peripheral neuromuscular sites. Both types of drugs are often effective as single-agent therapy although they also work well in combination with diuretics and other antihypertensive agents. Recently, there has been interest in a new transdermal method for administering the centrally-acting drug clonidine; the consistency of the plasma drug concentrations achieved by this form of treatment appears to minimize adverse effects while providing continuous therapeutic efficacy. Interest is also focusing on the ability of sympathoinhibitory agents such as alpha-methyldopa to produce regression of left ventricular hypertrophy, possibly by mechanisms independent of their antihypertensive action.

Adrenergic alpha-Antagonists↗
PubMed1984

Whole blood viscosity as a determinant of cardiac hypertrophy in systemic hypertension.

The relationships among blood pressure (BP), blood viscosity and echocardiographic left ventricular (LV) muscle mass were evaluated in 24 patients with essential hypertension and in 13 normotensive control subjects. LV mass was greater in the hypertensive patients than in the control subjects (225 +/- 69 vs 170 +/- 31 g, p less than 0.02) as was blood viscosity at a shear rate of 104 sec-1 (4.7 +/- 0.1 vs 4.3 +/- 0.2 cp, p less than 0.005). Among the hypertensive patients, LV mass was most closely related to viscosity at 104 sec-1 (r = 0.80, p less than 0.001), whereas only weak correlations were found between LV mass and systolic or diastolic BP (r = 0.45, p less than 0.05 for both). The 14 hypertensive patients with normal LV mass had viscosity similar to that in control subjects (4.5 +/- 0.3 vs 4.3 +/- 0.2 cp), whereas viscosity was consistently increased (5.0 +/- 0.4 cp, p less than 0.02) in hypertensive patients with LV hypertrophy. Thus, increased blood viscosity may be a determinant of or a response to hypertensive cardiac hypertrophy.

Adult↗
PubMed1984

The circadian blood pressure pattern in ambulatory normal subjects.

Ambulatory blood pressure (BP) monitoring using a portable noninvasive device capable of automatically measuring and recording BP every 7.5 minutes during a 24-hour study period was performed in 34 normal volunteers on 2 separate occasions, 2 to 8 weeks apart, to test the consistency of the whole-day blood pressure pattern. The average of all systolic BPs measured during the second study day was within 10 mm Hg of that measured during the first study day in 79% of the subjects, and the respective diastolic BP averages were within 5 mm Hg of each other in 65% of the subjects; 53% satisfied both of these criteria. The reproducibility of the circadian pattern of the BP was tested by dividing the 24-hour day into 12 consecutive 2-hour BP averages. When the corresponding 2-hour periods on the 2 study days were matched, there were strong correlations (r greater than 0.70) within most subjects for both the systolic and diastolic BP averages of the 2-hour periods (76% and 68% of subjects) and for the relative rank values of the periods (62% and 56%). Moreover, there were no significant differences between the averages (for all subjects together) on the 2 study days of the highest and lowest systolic and diastolic 2-hour BP values; similarly, the times at which these extreme values occurred on the 2 study days corresponded closely. Thus, in normal subjects there is a strong tendency for the circadian pattern and the actual levels of BP to be consistent between 24-hour study periods.

Adult↗
PubMed1984

Transdermal continuous antihypertensive therapy.

Self-adhesive patches containing a 7-day supply of transdermal clonidine were used to treat twenty patients with mild essential hypertension. These skin patches (3.5 cm2), which were changed by the patients every week, reduced diastolic blood-pressure to less than 90 mm Hg in twelve patients. When placebo-containing patches were substituted in these twelve patients after 3 months of treatment, blood-pressure rose slowly to its pretreatment level. Side effects appeared to be milder than those experienced during conventional oral antihypertensive treatment. Plasma clonidine concentrations were lower than peak levels after oral administration. This new method for treating hypertension was convenient and well tolerated, and may increase patient compliance.

Administration, Topical↗
PubMed1984

Clinical experience with rate-controlled delivery of antihypertensive therapy by a transdermal system.

The efficacy of transdermal clonidine, alone and in combination with diuretics, has been demonstrated in several studies involving patients with mild to moderate essential hypertension. In one 3-month open study, 64% of patients (wearing one to three 3.5 cm2 transdermal patches) achieved sustained blood pressure reductions throughout the treatment period. In this large study, side effects requiring discontinuation of drug were not observed. Transdermal clonidine reduced plasma renin activity and urinary aldosterone excretion to the same extent as that reported for oral clonidine. Renal function or serum electrolytes were not affected during therapy with transdermal clonidine. Another study showed that patients receiving oral clonidine and hydrochlorothiazide experienced comparable blood pressure reductions when switched to transdermal patches. Plasma drug concentrations measured during treatment with the transdermal patches were similar to the trough levels observed during treatment with oral clonidine. The equipotency of oral and transdermal therapy in combination with hydrochlorothiazide was also demonstrated in two remaining studies. In one of these studies it was suggested that daily variations in blood pressure induced by the peak and trough drug levels of the oral form were minimized by the stable drug levels characteristics of the transdermal device.

Administration, Oral↗
PubMed1984

Single-agent and combination therapy of essential hypertension.

Patients with mild to moderate essential hypertension were treated with beta-blockers and diuretics given separately and in combination. During single-drug therapy, the majority of patients exhibited clearly superior antihypertensive responses to either one type of drug or the other; only rarely were the beta-blockers and the diuretic equally effective in an individual patient. A poor response to diuretic therapy tended to predict a good response to a beta-blocker, and vice versa. Pretreatment renin measurements were not helpful in predicting the differing responses to single-drug treatment in this study population. These findings indicate that when one of these types of drug is ineffective as monotherapy in treating hypertension, the other type should be substituted before considering combination treatment. Combined therapy with the beta-blockers and diuretics also gave variable results, although poor antihypertensive responses could be attributed to excessive stimulation of the renin-aldosterone system by the diuretic component of the combination. The effectiveness of this form of treatment might thus be enhanced by the use of low diuretic doses.

Acebutolol↗
PubMed1984

Centrally acting antihypertensive agents: a brief overview.

There is growing acceptance of the centrally acting antihypertensive agents as single-agent therapy in the treatment of mild to moderate essential hypertension. An important characteristic of newer agents such as guanabenz is the absence of sodium retention during treatment, which minimizes the problem of tolerance seen with many of the established antihypertensive drugs. The centrally acting agents appear to work equally well in younger and older patients, and are also effective in both blacks and whites. They can be administered effectively and safely in hypertensive patients who have renal insufficiency. Moreover, it has been shown that guanabenz is effective in treating hypertensive diabetic patients; it does not change plasma glucose concentrations or the treatment requirements of diabetic patients. In general, the centrally acting agents appear to have no deleterious metabolic effects and may actually decrease the plasma concentrations of cholesterol. Their wide applicability and the absence of specific contraindications to their use make them attractive alternatives as first-line therapy for the treatment of hypertension.

Animals↗
PubMed1984

Hypertension in patients with diabetes mellitus: treatment with a centrally acting agent.

This retrospective study was undertaken to evaluate the effectiveness and clinical characteristics of guanabenz, a centrally acting agent, as monotherapy in hypertensive patients with coexisting diabetes mellitus. Of 113 patients with data available for analysis, 21 were receiving concurrent therapy with insulin, 31 were receiving oral hypoglycemic agents, and 61 were being treated by a diabetic diet alone. During treatment with guanabenz (4-64 mg daily) for up to 2 years (mean duration, 7 months), diastolic blood pressure (measured in the supine posture) decreased by an average of 10 mm Hg; the effects were similar among the three subgroups of patients receiving the different diabetic therapies. Clinically satisfactory treatment outcomes occurred in 52%, 77%, and 57% of patients, respectively. Body weight remained constant throughout the study. The antihypertensive efficacy of guanabenz in this study and the nature and frequency of side effects produced were similar to those reported previously in nondiabetic hypertensive patients. Neither plasma glucose concentrations nor the diabetic therapy requirements of the diabetic patients in this study were altered by guanabenz treatment. There also was a small decrease in serum total cholesterol concentration (mean decrease, 15 mg/dl, p less than 0.001) during the study. Thus, antihypertensive monotherapy with guanabenz is effective in the treatment of a majority of patients with coexisting diabetes mellitus. Since it does not appear to interfere with the concurrent treatment of diabetes or cause unwanted metabolic side effects, guanabenz may be a rational and safe agent for the management of hypertension in the diabetic patient.

Adult↗
PubMed1984

The effects of steroid hormones on vascular tissue.

Results of clinical and experimental studies suggest that extrarenal actions of corticosteroid hormones must be involved in the overall effects of these steroids on the circulation. A dissociation between levels of mineralocorticoids and sodium balance or renal effects of steroid hormones is often observed in patients with primary or secondary forms of hypertension. Receptors for various steroids have been found in the peripheral circulation. Stimulation of these receptors probably leads to changes in the electrolyte content of the cell. In turn, these changes have a direct or indirect effect on the contractility of the vascular wall. The physiological importance of the vascular effects of steroids in human hypertension remains to be elucidated.

Animals↗
PubMed1984

Comparative antihypertensive and endocrinologic effects of clonidine and prazosin in patients with essential hypertension.

The acute and chronic effects of fixed dosages of clonidine and prazosin on supine and upright blood pressure, the renin-angiotensin-aldosterone system, and plasma catecholamines were compared in 24 patients with essential hypertension. The patients were randomized into two groups; 11 received chlorthalidone (50 mg daily) throughout the protocol, but 13 received no diuretic. Clonidine was generally more effective in lowering systolic and diastolic blood pressure in the supine posture throughout the study; prazosin tended to decrease blood pressure in the upright posture more effectively, especially during the first week of treatment. The only truly significant difference was found after four weeks of treatment when the decrease in supine systolic blood pressure by clonidine of 26.5 +/- 8.9 mm Hg was greater than that of 1.7 +/- 5.6 mm Hg produced by prazosin (P less than .05).

Adult↗
PubMed1984

The calcium channel blocker nitrendipine in single- and multiple-agent antihypertensive regimens: preliminary report of a multicenter study.

The antihypertensive efficacy of the calcium channel blocker nitrendipine was evaluated in a 12-center collaborative study during 6 months of treatment. Following an initial placebo period, 318 patients with supine diastolic blood pressures greater than 90 mm Hg were given nitrendipine 5 mg twice daily for 1 week; if goal blood pressure was not reached (supine diastolic blood pressure less than 90 mm Hg with a fall of at least 10 mm Hg), the dose was doubled, and if necessary it was doubled again after an additional week. By the end of titration, goal blood pressure had been achieved in 132 patients (43%). During the subsequent 5 months of study, 155 patients continued to take nitrendipine alone; their post-titration supine diastolic blood pressure was 85 +/- 7 mm Hg, and at the end of the 6-month study it was 84 +/- 7 mm Hg. There were no changes in body weight or in heart rate. In 38 patients with a supine diastolic blood pressure of 95 +/- 9 mm Hg after titration, propranolol was added to the nitrendipine and decreased the supine diastolic blood pressure to 86 +/- 9 mm Hg by the end of the study; and in another 74 patients with a post-titration supine diastolic blood pressure of 93 +/- 7 mm Hg, addition of hydrochlorothiazide decreased the supine diastolic blood pressure to 86 +/- 7 mm Hg by the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Transdermal administration of clonidine for treatment of high BP.

The effectiveness of transdermally administered clonidine hydrochloride was evaluated in a multicenter study in 85 patients with mild essential hypertension. The drug was incorporated into small self-adhesive delivery systems (pliable skin patches, 3.5-sq-cm area) designed to continuously deliver 0.1 mg of clonidine hydrochloride per day. These devices were changed by the patients themselves at weekly intervals. Diastolic BP fell by at least 10% in 37 patients and was normalized (less than 90 mm Hg) in 54 patients (64%); 17 of these responding patients required only one skin patch, 27 required two, and the other ten responders required three. The antihypertensive action of the transdermal clonidine was sustained for the full three months of study. Side effects were similar to those during conventional oral treatment, but appeared to be milder.

Age Factors↗
PubMed1983

Effect of long-term antihypertensive therapy on cardiac anatomy in patients with essential hypertension.

M-mode echocardiography was used in 12 patients with essential hypertension to study changes in cardiac anatomy during long-term therapy with hydrochlorothiazide (50 to 100 mg) and alpha-methyldopa (500 to 1,750 mg). Echocardiographic examination was performed after six weeks of treatment with hydrochlorothiazide alone and after four to six weeks, six months, and nine months of treatment with both hydrochlorothiazide and alpha-methyldopa. Hydrochlorothiazide alone induced a small, and not significant, change in blood pressure (from 157 +/- 16 (SD)/105 +/- 9 to 150 +/- 14/101 +/- 5 mm Hg). Changes in echocardiographic parameters of cardiac anatomy were not observed during short-term diuretic therapy. Addition of alpha-methyldopa further reduced blood pressure (to 133 +/- 11/90 +/- 6 mm Hg, p less than 0.001), which was maintained throughout the study. Gradual decreases in diastolic septal thickness (from 10.9 +/- 1.1 to 9.5 +/- 1.0 mm, p less than 0.01), relative wall thickness (from 0.40 +/- 0.06 to 0.36 +/- 0.06, p less than 0.05) and left ventricular cross-sectional area (from 18.9 +/- 2.9 to 17.3 +/- 2.6 cm2, p less than 0.05) were observed. Posterior wall thickness did not change significantly during the study. The results provide evidence for regression of echocardiographic parameters of cardiac muscle mass during long-term antihypertensive treatment with a diuretic and a centrally-acting sympatholytic drug. Regression of left ventricular mass was not clearly related to changes in casual blood pressure. However, patients who showed a decrease in septal thickness tended to have a greater decrease in systolic blood pressure than those in whom septal thickness did not change during therapy. Moreover, patients in whom a decrease in left ventricular transverse dimension was observed, had a greater decrease in both systolic and diastolic blood pressure than those in whom left ventricular diastolic dimension did not change.

Adult↗