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Biomedical subjects

J I Drayer

Publications and source records attributed to J I Drayer.

At least 55 records · Page 3Linked to original sources
PubMed1983

Angiographic findings in homocystinuria.

Homocystinuria (HC) is an inborn error of amino acid metabolism characterized by ectopia lentis, mental retardation, and skeletal abnormalities. Vascular disorders may also occur in HC, although they are less common. Arteriographic studies of two sisters with HC are described. The younger woman's renal arteries showed wall irregularities and aneurysms, narrowing of the celiac and superior mesenteric arteries, and some aneurysmatic changes. In the older patient, irregular right carotid and splenic arteries were seen and a splenic aneurysm was present.

Adult↗
PubMed1983

Pyridoxine treatment does not prevent homocystinemia after methionine loading in adult homocystinuria patients.

Fasting homocystinemia in homocystinuria due to cystathionine synthase deficiency reportedly disappears on high-dose pyridoxine treatment. This does not necessarily reflect normal tolerance to methionine. The present study compares the effects of oral methionine loading on homocystine, cystine, and homocysteine-cysteine disulphide profiles in 8 adult homozygous homocystinuria patients on and off pyridoxine treatment and in 20 controls. Pyridoxine nearly normalized fasting serum amino acid levels. Nevertheless, with a similar methionine load the patient's homocystine levels on and off treatment rose and the cystine levels decreased, reflecting the ongoing formation of the homocysteine-cysteine disulphide in the presence of impaired transsulphuration of homocysteine. In the controls homocystinemia remained virtually absent and cystine transiently rose which indicates normal transsulphuration. On treatment methionine loading evoked a brisk rise of the homocysteine-cysteine disulphide levels to values equal to those off treatment, when these levels virtually plateaued after the load. Thus, pyridoxine treatment attenuates the biochemical abnormalities in the fasting patients but leaves their impaired capacity to handle major methionine loads essentially unchanged.

Adult↗
PubMed1983

Cardiac muscle mass during vasodilation therapy of hypertension.

M-mode echocardiography has become a valuable tool in the evaluation of changes in left ventricular muscle mass during antihypertensive therapy. We evaluated the effects of treatment with the vasodilator trimazosin, alone and in combination with the diuretic polythiazide, on cardiac muscle mass in hypertensive subjects. Trimazosin alone was given to 11 subjects for 18 mo, and average supine blood pressure fell from 154/100 to 146/89 mm Hg. Heart rate and body weight did not change during therapy. Initially, a slight decrease (approximately 6%) was observed in left ventricular muscle mass, but left ventricular transverse dimension and left ventricular muscle mass returned to control levels during the last 6 mo of the 18-mo study. The combination of trimazosin and polythiazide was given to nine subjects and decreased blood pressure from 152/102 to 138/92 mm Hg. Heart rate increased and body weight decreased slightly. No changes in left ventricular muscle mass were observed during combination therapy. It is possible that increases in activity of the sympathetic nervous system during therapy with trimazosin alone, and the observed increase in renin activity during treatment with trimazosin and polythiazide, might have offset the effects of the reduction in blood pressure on left ventricular muscle mass.

Adult↗
PubMed1983

Effects of low-dose antihypertensive therapy in elderly patients with predominant systolic hypertension.

Patients over 60 years of age (M = 70 years) with the predominant systolic form of essential hypertension (systolic blood pressure greater than 160 mm Hg; diastolic blood pressure less than 100 mm Hg) were treated with a combination of low doses of the diuretic chlorthalidone and the centrally-acting sympatholytic agent clonidine. In this randomized double-blind study, patients received either active treatment (n = 14) or placebo (n = 16). Baseline systolic blood pressure in the treatment group averaged 172 mm Hg and was controlled (fall in systolic blood pressure to less than 140 mm Hg or by at least 10%) in 13 of the 14 patients; in eight patients, control was achieved with a single daily dose (given at night) of the clonidine (.1 mg)-chlorthalidone (15 mg) combination. The active drug was significantly superior to placebo in decreasing systolic blood pressure. Changes measured in the standing position did not differ from those in the supine position. Side effects were mild and transient for both the placebo and the treatment groups. Low-dose combination therapy appears to be a highly effective approach for the management of older patients with predominant systolic hypertension of mild-to-moderate degree.

Aged↗
PubMed1983

Combined diuretic and sympatholytic therapy in elderly patients with predominant systolic hypertension.

It has been speculated that the convenience and palatability of low-dose combination antihypertension treatment might enhance therapeutic effectiveness and compliance, especially in elderly patients. To test this possibility, patients over 60 years of age with predominant systolic hypertension were treated with a combination of a diuretic, chlorthalidone, and the centrally acting inhibitor of sympathetic activity, clonidine. The results of active treatment in these patients (n = 13) were compared with those of a placebo (n = 11). Active therapy with low doses of chlorthalidone and clonidine (usually once daily) controlled blood pressure (systolic pressure less than 140 mm Hg) in 12 of the 13 patients without inducing orthostatic hypotension. Administration of placebo did not result in significant changes in blood pressure. The diuretic-clonidine combination induced only small decreases in serum potassium levels and small increases in uric acid; no significant changes in creatinine clearance were observed. Both active and placebo therapy were tolerated without significant side effects. This study reveals that combined therapy with low doses of chlorthalidone and clonidine is effective, convenient, and palatable in controlling blood pressure in elderly patients with predominant systolic hypertension and supports the idea that treatment with sympathoinhibitory and volume-depleting agents is appropriate for this form of hypertension.

Aged↗
PubMed1983

The use of short-term ambulatory blood pressure monitoring in differing forms of hypertension.

Single blood pressure readings represent the conventional approach for determining the presence and severity of hypertension. However, the relationship between single (casual) readings and the whole-day blood pressure average is weak, especially in patients with borderline hypertension and in the elderly. In this study we have compared casual blood pressures with the averages of blood pressures obtained during short-term (two-hour) and long-term (24-hour) ambulatory monitoring in patients with mild (n = 19), moderate (n = 11), or predominant systolic (n = 11) essential hypertension. The blood pressure averages obtained during long-term monitoring were significantly lower than the casual blood pressure in all three subgroups. The averages of short-term monitoring in the morning were in between the other two blood pressure levels. The correlation coefficients between two-hour morning averages of pressure and whole-day averages were highly significant (p less than 0.01 or better), and stronger than those between casual and whole-day average pressures, in the group of patients as a whole and in all three subgroups. The slopes of the regression equations were close to unity. Therefore, ambulatory short-term monitoring of blood pressure in the morning is superior to casual blood pressure and probably is an adequate substitute for whole-day observations in quantifying whole-day blood pressure levels in hypertensive patients, especially in patients with mild hypertension and in those with predominant systolic hypertension.

Blood Pressure↗
PubMed1983

BP as a determinant of cardiac left ventricular muscle mass.

The relationship between casual BPs and measures of cardiac hypertrophy, derived from the ECG, has been described as fairly weak. In this study, ECG and echocardiographic measurements of left ventricular muscle mass were related to various measures of BP obtained during circadian ambulatory BP monitoring in 12 patients with hypertension. Casual BP did not correlate substantially with ECG voltages or with echocardiographic measurements of muscle mass. The correlations between whole-day, daytime, or nighttime BP averages and ECG voltages were not significant. However, echocardiographic left ventricular muscle mass correlated significantly with the averages of whole-day, daytime, and nighttime, and two-hour morning systolic pressures. The correlations between diastolic BP and left ventricular muscle mass were not significant. Therefore, serial BP measurements are required to evaluate the relationship between BP and left ventricular muscle mass as measured by the M-mode echocardiogram. The ECG is of little value in this relationship.

Adult↗
PubMed1983

Long-term BP monitoring in the evaluation of antihypertensive therapy.

Noninvasive BP monitoring was performed in hypertensive patients before and during placebo therapy and before and during therapy with the long-acting peripheral alpha-adrenergic receptor antagonist, terazosin hydrochloride. Placebo therapy did not result in significant changes in casual BP or in averages of whole-day, daytime, or nighttime BPs. Short-term therapy with terazosin did not induce significant changes in casual supine or daytime BPs. However, whole-day BP monitoring disclosed that nighttime BPs were lower during shortterm therapy. Moreover, the circadian pattern of BP was shifted downward during terazosin therapy. Long-term therapy with terazosin resulted in significant changes in BP. All BP values were lowered significantly. The differences in the circadian BP pattern between placebo and long-term terazosin therapy show that in these patients BP was lowered throughout the 24 hours of the day. The results of the study emphasize the usefulness of 24-hour BP monitoring in the evaluation of the effectiveness of long-acting antihypertensive agents.

Adult↗
PubMed1983

Effects on the renin-angiotensin system of agents acting at central and peripheral adrenergic receptors.

Although the principal actions of clonidine are linked to its centrally mediated suppression of sympathetic activity, its inhibition of the renin axis also may contribute to its antihypertensive effects. In patients with essential hypertension studied in a clinical research center, clonidine-induced decreases in diastolic blood pressure and in plasma renin activity (PRA) correlated closely after one day of treatment, but not thereafter. Moreover, high-renin patients experienced significantly greater blood pressure decrements than low-renin patients during the first day of treatment, but subsequent blood pressure decreases were equal in the two groups, confirming that the sympathoinhibitory action of clonidine is probably independent of the renin-angiotensin system. However, responders to clonidine treatment exhibited significantly greater decrements in aldosterone excretion rate than nonresponders. When compared with propranolol in an outpatient study, clonidine reduced aldosterone levels to the same extent as propranolol despite a significantly weaker inhibitory effect on PRA. Indeed, in a further comparative study with prazosin, during which neither agent decreased renin levels, clonidine significantly lowered aldosterone excretion. Thus, clonidine appears to have two separate actions on the renin-aldosterone axis: an early antirenin action primarily in high-renin patients, and a longer-term suppressive effect on aldosterone. This latter action is possibly independent of changes in renin, and perhaps reflects an effect on aldosterone release mediated through central mechanisms.

Adult↗
PubMed1982

A representative value for whole-day BP monitoring.

Shorter-term alternatives to 24-hour monitoring of BP were analyzed in six hypertensive patients. Average BPs during the 24-hour period were lower than averages during a two-hour morning period or those based on either three readings or a single reading taken at 8 AM. The systolic and diastolic BP two-hour averages correlated more strongly with the 24-hour averages than did the three-reading or single-reading alternatives. Thus, the average of serial BP readings obtained during a two-hour morning period is a consistent predictor of the whole-day BP and represents it more closely than the conventionally used single reading.

Blood Pressure Determination↗
PubMed1982

Circadian blood pressure patterns in ambulatory hypertensive patients: effects of age.

Circadian blood pressure monitoring was performed in 50 untreated ambulatory hypertensive patients to study the effects of age on the pattern and variability of blood pressure and heart rate. Casual blood pressure, measured in the morning, was greater than the average of the blood pressures measured at 7.5 minute intervals for 24 hours (148 +/- 2/95 +/- 2 and 137 +/- 2/88 +/- 2 mm Hg, p less than 0.001). The correlation between casual systolic pressure and the 24 hour average was stronger (p less than 0.05) in younger (less than 55 years of age) patients (r = 0.69, n = 24, p less than 0.001) than in older patients (r = 0.42, n = 26, p less than 0.1). Similarly, diastolic pressures correlated more strongly (p less than 0.05) in younger patients (r = 0.71, p less than 0.001) than in older patients (r = 0.43, p less than 0.05). Variability of systolic pressure, defined as the standard deviation of all readings obtained during 24 hours, was greater than that of diastolic pressure (16.7 and 13.1 mm Hg, respectively, p less than 0.001). Moreover, the variability of systolic pressure was greater in older than in younger patients (18.1 and 15.2 mm Hg, respectively, p less than 0.01). The variability of diastolic pressure was slightly but not significantly greater in older patients (13.7 and 12.5 mm Hg, not significant). The circadian pattern of blood pressure, expressed as averages of readings obtained during consecutive 2 hour intervals, was similar in the two age groups. However, the level of systolic pressure was consistently higher (p less than 0.01) and that of both diastolic pressure and heart rate consistently lower (p less than 0.01) in older patients. Thus, ambulatory circadian blood pressure monitoring reveals significant changes in blood pressure levels and its variability with age; the casual blood pressure does not accurately reflect these changes. Longer periods of blood pressure monitoring are required for accurate assessment of the characteristics of hypertension in the aged.

Adult↗
PubMed1982

Changes in ventricular septal thickness during diuretic therapy.

We report on changes in echocardiographic parameters of left ventricular muscle mass in 20 hypertensive patients during short-term therapy with hydrochlorothiazide. In the group as a whole, blood pressure fell, but septal thickness and posterior wall thickness did not change. Septal thickness decreased in nine patients, and in all of these patients calculated left ventricular cross-sectional area also decreased. Septal thickness did not change or increased in 11 patients and in only one of these patients did cross-sectional area increase. These increases in septal thickness usually were associated with decreases in left ventricular transverse dimension. We therefore conclude that the increases in left ventricular wall and septal thickness during diuretic therapy probably reflect an adaptive change of cardiac muscle tissue around a smaller left ventricle.

Adult↗