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Biomedical subjects

J I Drayer

Publications and source records attributed to J I Drayer.

At least 19 recordsLinked to original sources
PubMed1987

The adrenergic inhibitors.

Although most of the centrally and peripherally-acting adrenergic inhibitors have been available for several years, they continue to contribute importantly to antihypertensive therapy. There are remarkably few contraindications to their use. They are useful in hypertension of all grades of severity, and are also valuable in complicated forms of hypertension, such as those associated with renal insufficiency, diabetes mellitus, and chronic obstructive lung disease. They can produce some fairly predictable side effects in patients, but generally do not cause significant metabolic changes. These drugs also seem to be tolerated well by physically active patients. They appear to have desirable effects on cardiac structure. In general, the adrenergic inhibitors cause regression of a left ventricular hypertrophy, which may well be a valuable property, especially in older hypertensive patients.

Adrenergic alpha-Antagonists↗
PubMed1987

Disparate relationships between blood pressure and left ventricular mass in patients with and without left ventricular hypertrophy.

The relationship between casual blood pressure and left ventricular (LV) mass has been reported to be fairly weak in hypertensive patients. In this study we analyzed this relationship using noninvasive devices to monitor blood pressure for 24 hours in ambulatory patients and M-mode echocardiography to determine LV mass. Among the 33 patients with hypertension, 21 had echocardiographic LV hypertrophy (LV mass greater than 250 g). Patients with LV hypertrophy did not differ significantly from patients without hypertrophy with respect to age or casual systolic or diastolic blood pressure. The averages of whole-day systolic and diastolic blood pressures were 146 +/- 17 (SD) over 90 +/- 12 and 136 +/- 16 over 89 +/- 12 mm Hg, respectively. The relationship between whole-day average systolic blood pressure and LV mass was significantly positive (r = 0.66, p less than 0.05) in patients without hypertrophy but was not significant in patients with LV hypertrophy (r = -0.24). Similarly, the relationship between whole-day average diastolic blood pressure and LV mass was significantly positive in the former group (r = 0.64, p less than 0.05) but significantly negative in hypertensive patients with LV hypertrophy (r = -0.67, p less than 0.01). Thus, blood pressure correlates positively with LV mass only in patients without cardiac hypertrophy. In hypertensive patients with LV hypertrophy, factors additional to the high blood pressure itself must participate in the regulation of LV mass.

Blood Pressure↗
PubMed1987

Doppler echocardiographic assessment of left ventricular systolic and diastolic function in mild hypertension.

Abnormalities in left ventricular (LV) wall thickness and mass have been demonstrated in patients with mild hypertension utilizing M-mode echocardiography. In addition, studies using radionuclide angiography have demonstrated abnormalities in early diastolic LV filling in asymptomatic hypertensive patients with normal ejection fraction and cardiac output. Recently, Doppler recordings of flow velocity in the ascending aorta and through the mitral valve have been shown to provide useful information about LV function. To determine whether flow abnormalities could be detected in patients with mild hypertension, we recorded Doppler aortic and mitral valve flow velocities in 21 men with mild hypertension. Casual systolic blood pressure was 147 +/- 18 mm Hg (mean +/- SD) and diastolic blood pressure was 96 +/- 9 mm Hg. LV mass (310 +/- 75 g) was elevated (i.e., above the 95% normal prediction interval) in 8 of 19 patients who underwent M-mode echocardiography; LV ejection fraction was normal in all patients (mean, 80%). As in previous studies in normal subjects, we found in these hypertensive patients an inverse correlation between age and both aortic peak flow velocity (r = -0.51, p less than 0.05) and transmitral early diastolic peak flow velocity (r = -0.44, p less than 0.05) and a positive relationship between age and mitral valve late diastolic peak flow velocity (r = 0.73, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Effect of the calcium channel blocker nitrendipine on left ventricular mass in patients with hypertension.

Reductions in left ventricular (LV) mass have been reported after antihypertensive therapy with certain sympatholytic agents and converting enzyme inhibitors, but little or no improvement has been noted after vasodilator therapy. In this study we evaluated the effect of the calcium channel blocker nitrendipine on echocardiographic LV mass. During a 12-month period, nitrendipine was used as monotherapy in 30 patients and in combination with propranolol or a diuretic in an additional 28 patients. Nitrendipine monotherapy lowered supine blood pressure from 148/97 to 136/83 mm Hg, but LV mass did not change significantly. Supine blood pressure decreased from 155/103 to 134/86 mm Hg in patients receiving combination therapy but, again, changes in LV mass were not significant. These data suggest that nitrendipine is effective in lowering blood pressure, but this is not associated with a significant decrease in LV mass in patients with mild hypertension.

Adult↗
PubMed1986

Echocardiographic evaluation of left ventricular hypertrophy.

Echocardiography represents an innovative diagnostic method in patients with mild hypertension because it allows evaluation of target organ involvement and, thus, potentially may be of value in determining which patients might most benefit from treatment. In large-scale observations of mild to moderate hypertension, the electrocardiogram and the chest x-ray film each identified approximately 5% of patients as having left ventricular hypertrophy (LVH), whereas echocardiography demonstrated this finding in almost 50%. This high sensitivity also was found in a study of young hypertensive patients (average age 28 years) among whom over 30% had left ventricular muscle wall thicknesses greater than the highest value found in age-matched normotensive controls; additionally, evidence for LVH was documented in a subgroup of young patients with labile hypertension whose blood pressure actually were normal at the time of the echocardiographic procedure. Blood pressure is not the only cause of LVH. Other factors, including heightened activity of the sympathetic nervous system and the renin axis, may be important. Thus, treatment of hypertension with agents such as diuretics or vasodilators that fail to decrease sympathetic activity, or which might even increase it, often fails to produce regression of LVH. In contrast, agents with sympatholytic properties may exhibit beneficial effects on left ventricular muscle mass that are independent of their actions on blood pressure.

Aging↗
PubMed1986

Treatment of hypertension in the elderly.

We have evaluated the effectiveness of antihypertensive therapy for predominant systolic hypertension in 55 patients, aged 61 to 76 years, with untreated systolic blood pressures of at least 160 mm Hg and diastolic blood pressures less than 100 mm Hg. In this retrospective analysis, 41 of the patients had been treated with the centrally acting agent guanabenz (average dose 24 +/- 14 [SD] mg daily) given alone, and 14 had received a combination of guanabenz (17 +/- 10 mg daily) and hydrochlorothiazide (60 +/- 30 mg daily). After six months of therapy, each regimen significantly decreased both systolic and diastolic blood pressures. Moreover, there were no differences between the two treatment regimens in their antihypertensive efficacy, and there was no evidence of orthostatic effects. In both treatment groups, approximately 50% of the patients had excellent therapeutic responses (decrease in supine systolic blood pressure of at least 20 mm Hg). The main side effects of treatment were drowsiness and dry mouth, though these tended to be mild and of short duration. Thus, in predominant systolic hypertension in elderly patients, guanabenz, either alone or in combination with a diuretic, appears to be an effective and well tolerated form of treatment.

Aged↗
PubMed1986

Endogenous opioid peptides: do they mediate the acute antihypertensive action of clonidine in humans?

The involvement of endogenous opioid peptides in the antihypertensive action of acutely administered clonidine, a centrally acting adrenergic agonist, was studied in humans. Eight hypertensive subjects received clonidine 0.2 mg orally, naloxone 8 mg i.v. followed by a 0.13 mg/min infusion, and both drugs together on separate days. Clonidine resulted in a significant decrease in mean blood pressure, which was not affected by concomitant treatment with naloxone. Naloxone alone or with clonidine caused significant elevations in plasma aldosterone, not mediated by increased plasma renin activity. Plasma beta-endorphin was not increased after clonidine administration. In humans, the antihypertensive effects of acute clonidine administration do not appear to be mediated by the release or action of endogenous opioids.

Adult↗
PubMed1985

Enhancement of the pressor response to norepinephrine by angiotensin in the conscious rabbit.

The pressor interactions between angiotensin II and norepinephrine were investigated in conscious New Zealand white rabbits receiving a low sodium diet. Angiotensin II was administered continuously by intraperitoneal osmotic pumps in a subpressor dose so as to avoid the potentially confounding effects of experimentally-induced hypertension. Norepinephrine challenges were given as a series of graded intravenous boluses. During the 3 days of study the baseline blood pressure in the angiotensin-treated rabbits (n=10) did not differ from that in controls (n=10) whose intraperitoneal pumps contained only diluent. After 24 hours the systolic and diastolic blood pressure responses to norepinephrine in the angiotensin-treated group were, on average, 45% and 30% higher than in the controls; after 72 hours, they were 46% and 34% higher. Although the pressor amplitudes were increased by angiotensin II, they were not prolonged. Thus, facilitation by the subpressor angiotensin II of the blood pressure responses to norepinephrine did not seem dependent upon alterations in endogenous sympathetic mechanisms or the uptake of norepinephrine; nor could it be explained by sodium retention. It is possible that angiotensin II exhibits its effect by enhancing contractile responsiveness to norepinephrine at the postreceptor level.

Angiotensin II↗
PubMed1985

Automated ambulatory blood pressure monitoring: a study in age-matched normotensive and hypertensive men.

Noninvasive automated techniques have been used in this study in 29 ambulatory normotensive and hypertensive men to monitor blood pressure during a full 24-hour period. The two groups of men were carefully matched for age. The data were analyzed with respect to possible differences in the circadian pattern of blood pressure, in the variability of blood pressure, and differences in the prevalence of abnormal blood pressures between the two groups. The circadian pattern of blood pressure in hypertensive patients was displayed parallel to that in normotensive control subjects but at a significantly higher level. The difference between daytime and nighttime systolic blood pressure was greater in normotensive than in hypertensive men. However, variability of blood pressure was not different between the two subgroups. 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% of abnormal readings of systolic or diastolic blood pressures during a 24-hour recording period. In contrast, fewer than 25% of abnormal blood pressure readings were found in nine 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

Once-daily administration of acebutolol in treatment of hypertension.

A comparison of once-daily and twice-daily regimens of treatments with a beta-adrenoceptor-blocking agent, acebutolol, was carried out in patients with mild to moderate essential hypertension. Following an initial placebo phase, all patients entered an open 9-week period during which the dose of acebutolol, given on a twice-daily basis to all patients, was titrated to reduce seated diastolic blood pressure to less than 90 mm Hg or to decrease it by at least 10 mm Hg. After a further 4-week maintenance period, patients whose blood pressure had been successfully controlled entered a 3-month double-blind study in which they were randomly divided into three groups: those receiving continuation of twice-daily treatment (n = 47); those receiving once-daily treatment (using the same total daily dose as in the earlier twice-daily phase (n = 97); and those receiving placebo twice daily (n = 48). By the end of the study, 78% of the once-daily treatment group were still under control, a result similar to that of 72% in the twice-daily treatment group. In contrast, only 39% of the placebo patients remained under control. Moreover, the blood pressure in this group was significantly higher than in the other two groups. Acebutolol is an efficacious antihypertensive agent when used on a once-daily basis.

Acebutolol↗
PubMed1985

Disparate responses of blood pressure to adrenergic stimuli during beta blockade.

Insulin hypoglycemia or epinephrine release may lead to adverse increases in blood pressure in the presence of non-cardioselective beta-blockers. However, increases in blood pressure have not been observed in beta-blocker treated patients during physical exercise, handgrip tests, or during infusions with the alpha-adrenergic agonist, phenylephrine. In this study we have further evaluated the role of adrenergic stimuli in the etiology of these responses of blood pressure during beta-blocker therapy. These data do not support a direct role for beta 2 receptors or norepinephrine in pressor responses observed during beta-blocker therapy. Blockade of beta 1 receptors or, more likely, a facilitating effect of propranolol upon the alpha-adrenergic receptors might explain the enhanced pressor responses found after administration of the alpha-adrenergic agonist, phenylephrine. However, high doses of phenylephrine seem needed to elicit such pressor responses.

Adrenergic beta-Antagonists↗
PubMed1985

Severe hypertension induced by naloxone.

To evaluate the role of endogenous opioid peptides in regulating the blood pressure of hypertensive individuals, we administered the opiate antagonist, naloxone. One individual developed a severe hypertensive response, mean arterial pressure rising from a baseline of 107 mmHg to 147 mmHg 145 min after naloxone injection and infusion. After stopping naloxone, his blood pressure rapidly returned to baseline. Re-challenge with naloxone and clonidine resulted in a modest reduction of blood pressure in contrast to the profound hypotension induced by clonidine alone during a third session. Thus, endogenous opioids appear to regulate blood pressure in some hypertensive patients and opiate antagonists must be administered with caution to these individuals.

Blood Pressure↗
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↗