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Biomedical subjects

V DeQuattro

Publications and source records attributed to V DeQuattro.

At least 55 records · Page 3Linked to original sources
PubMed1988

Labetalol blunts morning pressor surge in systolic hypertension.

Twenty-four-hour ambulatory blood pressure, including the acceleration phase, and left ventricular mass were evaluated in 16 patients with isolated systolic hypertension (standing blood pressure greater than or equal to 160 mm Hg systolic and less than or equal to 95 mm Hg diastolic). After a 4-week, single-blind, placebo period, each patient underwent 24-hour ambulatory blood pressure monitoring and echocardiography. Labetalol therapy was then initiated at 100 mg twice a day in a single-blind manner and increased weekly by 100 mg twice a day until blood pressure control was obtained or a maximum dosage of 400 mg twice a day was reached. Blood pressure control was achieved at a mean daily dose of 363 +/- 46 mg of labetalol. Measurements were repeated at the end of an 8-week maintenance phase. Labetalol therapy significantly reduced the mean 24-hour systolic ambulatory blood pressure from 154 +/- 8 (mean +/- SEM) mm Hg at baseline to 142 +/- 6 mm Hg (p greater than 0.01) and controlled the early morning surge in systolic ambulatory blood pressure. Minor reductions in diastolic blood pressure and heart rate were statistically but not clinically significant. Left ventricular mass was not changed. Labetalol monotherapy provides effective 24-hour control of systolic blood pressure, including the acceleration phase, in patients with isolated systolic hypertension.

Blood Pressure↗
PubMed1988

Noradrenergic hyperactivity in primary hypertension; central and peripheral markers of both behavioral pathogenesis and efficacy of sympatholytic and relaxation therapy.

The effects of clonidine or relaxation therapy were determined in two separate groups of patients with primary hypertension. Ten patients were treated with clonidine monotherapy for 3 months. There were concurrent reductions of blood pressure, plasma and CSF norepinephrine, all p less than 0.01. The changes of blood pressure and norepinephrine were correlated, p less than 0.05 and 0.01, respectively. Thirty patients received hygienic instructions, and 17 of them had relaxation training in addition. Relaxation lowered blood pressures, p less than 0.01, the reduction of blood pressure was related to baseline plasma norepinephrine, p less than 0.05, and greater in patients with "raised" plasma norepinephrine, p less than 0.02. Plasma norepinephrine was lowered after hygienic therapy, p less than 0.05, the change was not significant after relaxation training. Arterial pressure elevation appears to be related to raised plasma norepinephrine. This noradrenergic hyperactivity is a marker for blood pressure responsiveness to sympatholytic therapy with clonidine or relaxation techniques.

Adult↗
PubMed1988

Primary hypertension: left ventricular mass and function, sympathetic nervous system activity, and therapy.

Left ventricular (LV) mass is a predictor of morbidity in patients with hypertension. To elucidate the mechanisms of left ventricular hypertrophy (LVH) in primary hypertension, we examined the relationships of LV mass, arterial blood pressure, and plasma norepinephrine--as a marker of sympathetic nervous system tone--in three populations of patients with mild or moderate hypertension. We found linking of neural tone with (a) arterial blood pressure in mild and moderate hypertension, (b) LV mass in moderate hypertension, and (c) diastolic function in mild hypertension, suggesting that neural tone is a factor in both the pathogenesis and the sequelae of hypertension. Additionally, elevated norepinephrine level may reflect subtle loss of diastolic function before hypertrophy is manifest. Both nondrug and drug therapy may regress LV mass after blood pressure reduction with disparate effects on neural tone.

Adult↗
PubMed1988

Effects of antihypertensive agents on circadian blood pressure and heart rate patterns. Review.

Blood pressure and heart rate exhibit a circadian rhythm, with both rising rapidly during the morning hours and then decreasing throughout the day to a nadir around 3 AM. Current evidence suggests a possible link between cardiovascular events, such as myocardial infarction and sudden cardiac death, which have been shown to occur most frequently during the morning hours, and the rapid rise in blood pressure and heart rate during this same time period. We review data from ambulatory blood pressure studies to ascertain which antihypertensive agents provide the most satisfactory control of blood pressure and heart rate during the hours of 6 AM to 12 noon. Of the forms of drug therapy studied, labetalol, a combined alpha- and beta-blocker, and two calcium channel blockers, nifedipine and verapamil, appear to be the most effective in blunting the rise in arterial blood pressure during these critical morning hours.

Antihypertensive Agents↗
PubMed1987

Efficacy of bucindolol in systemic hypertension.

The hemodynamic effects of oral bucindolol, a non-selective beta-adrenergic blocking agent with intrinsic sympathomimetic activity and direct vasodilating properties, were studied at rest and during handgrip exercise with a flotation-directed pulmonary artery catheter in 12 patients with mild to moderate essential hypertension. After the initial dose of 150 mg of bucindolol, blood pressure (BP) was significantly reduced and cardiac output was increased (from 5.9 +/- 0.8 to 6.8 +/- 1.6 liters/min) in the supine position and during exercise (p less than 0.05). Systemic vascular resistance was reduced (from 1,555 +/- 339 to 1,311 +/- 467 dynes s cm-5, p less than 0.01) at rest and without significant changes during exercise. There were increases in heart rate (13 +/- 13%, p less than 0.01) and right atrial (69 +/- 77%, p less than 0.05), pulmonary arterial (38 +/- 24 %, p less than 0.001) and pulmonary artery wedge pressures (62 +/- 46%, p less than 0.001) during exercise. Bucindolol did not change these variables at rest or during exercise. Bucindolol increased plasma norepinephrine levels both at rest (from 330 +/- 151 to 588 +/- 320 ng/liter, p less than 0.01) and during exercise (from 468 +/- 220 to 685 +/- 390 ng/liter, p less than 0.05). After 4 weeks of bucindolol with doses of 50 to 200 mg 3 times daily, BP was reduced in both supine and standing positions (mean arterial BP of 11 +/- 7% [p less than 0.001] and 11 +/- 6% [p less than 0.001], respectively), without changes in cardiac output, systemic vascular resistance or plasma norepinephrine level.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1987

The 1980s: a patient-specific therapeutic approach in hypertension.

The conventional "stepped-care" approach to the treatment of hypertension deserves revision. Rational therapy considers a variety of factors to obtain maximum efficacy, safety, tolerability, compliance, and neutralization of neural tone for the prevention of sudden death. The patient's age, gender, race, behavior profile, hemodynamic and neurohumoral status (plasma renin activity, norepinephrine/epinephrine ratio), and quality of life will help determine the choice of antihypertensive agent. Concomitant risk factors (smoking, obesity, diabetes, hypercholesterolemia), the presence of sequelae (left ventricular hypertrophy and/or failure, renal failure), and the existence of other disorders (mitral valve prolapse, depression, anxiety) must also be considered when initiating treatment. In addition, the cost of ancillary expenses (laboratory tests, hospitalizations, and emergency room visits) must be weighed against the potential benefits of therapy. Beta blockers are effective, well tolerated, and versatile for the treatment of concomitant cardiovascular disorders and as behavior modifiers. Calcium channel blockers and angiotensin converting enzyme inhibitors also show promise and merit consideration as therapy for specific groups of hypertensive patients.

Adrenergic beta-Antagonists↗
PubMed1987

Neurohumoral mechanisms and left ventricular hypertrophy: effects of hygienic therapy.

To determine the effects of hygienic (non-drug) therapy on blood pressure (BP) control and its relationship to sympathetic tone and left ventricular mass (LVM) in primary hypertension, plasma norepinephrine (NE) and renin activity (PRA), LVM, and nutritional and behavioral status were assessed in 76 borderline to mild hypertensives. Pretherapy plasma NE was related to diastolic blood pressure (DBP) and PRA (r = 0.24, P less than .05 and r = 0.37, P less than .01, respectively). Plasma NE of high renin patients (221 +/- 52) (mean +/- SD) was greater than that of normal renin patients (159 +/- 61, ng/l, P less than .01). LVM was related to systolic blood pressure (SBP) (P less than .001), DBP (P less than .01) and urinary sodium (P less than .05), and inversely related to PRA (P less than .01). Septal wall thickness was related to hostility (r = 0.42, P less than .05). After seven weeks of hygienic therapy, DBP was reduced by 6 mmHg (P less than .01). The change in SBP was related to baseline plasma NE (P less than .05) and inversely related to LVM (P less than .05). These results suggest that raised sympathetic tone may be a pathogenic factor in primary hypertension and that hygienic therapy lowers BP more effectively in patients with raised sympathetic tone and low LVM.

Adult↗
PubMed1987

Liquid-chromatographic measurement of catecholamines and metabolites in plasma and urine.

In this general method for measuring the concentrations of neurotransmitters in body fluids by "high performance" liquid chromatography (HPLC), the procedures for extracting different biogenic amines from body fluids vary, but the basic chromatographic conditions are the same for all. We use citric/formic acid buffer as the mobile phase, a C18 column, and an electrochemical detector. Specificity is better than in previously reported methods. Because of its excellent cost efficiency, we consider this to be the method of choice for quantifying biogenic amines.

Antihypertensive Agents↗
PubMed1986

Childhood familial pheochromocytoma. Conflicting results of localization techniques.

Childhood familial pheochromocytoma was investigated in four patients by abdominal computed tomographic scan, [131I]metaiodobenzylguanidine scan, and vena caval catecholamine sampling. Results conflicted with surgical findings. Computed tomographic scan identified all four adrenal tumors but missed two midline tumors in one patient. [131I]metaiodobenzylguanidine scan identified two of three adrenal tumors but also suggested extra-adrenal tumors not confirmed at operation in two of three patients. Vena caval sampling for catecholamines confirmed all adrenal tumors but suggested additional tumors not verified at operation in two of three patients. All patients are asymptomatic and have normal urinary catecholamines 15 to 51 months after operation. Because of the frequency of multiple tumors in familial pheochromocytoma, different diagnostic techniques were employed. False-positive results were more frequent with [131I]metaiodobenzylguanidine and vena caval sampling. Reinterpretation of the [131I]metaiodobenzylguanidine scans at a later date led to less false-positive interpretation, although the false-negative rate remained unchanged. More pediatric experience with [131I]metaiodobenzylguanidine scans and vena caval sampling in familial pheochromocytoma is needed. Confirmation of tumor and its localization rest with meticulous surgical exploration.

3-Iodobenzylguanidine↗
PubMed1985

Effects of exercise on blood pressure, plasma catecholamines, potassium and the electrocardiogram after diuretic and neural-blocking therapy for moderate hypertension.

Blood pressure control in mild and moderate hypertension may reduce morbidity and mortality. On the other hand, antihypertensive drugs may cause adverse metabolic, electrolyte, neural and hemodynamic alterations that detract from their effectiveness. The effect of hydrochlorothiazide (HCTZ) on some of these factors was compared with that of HCTZ and a sympatholytic drug in 20 hypertensive patients with left ventricular hypertrophy and retinopathy. HCTZ controlled blood pressure at rest and during maximum treadmill exercise (-12 mm Hg systolic and diastolic pressure (p less than 0.05), reduced left ventricular mass by 7% (p less than 0.05) and lessened aerobic impairment at maximum treadmill exercise by 45% (p less than 0.05). These effects were further improved after "neural blockade." A potential adverse effect of HCTZ--hypokalemia (-0.6 mEq/liter, p less than 0.01)--and the associated incidence of ectopy during effort (50%) were lessened after neutralizing neural tone. Combination therapy with low-dose diuretic and sympatholytic drugs was effective and well tolerated in patients with cardiac and vascular sequelae of moderately severe hypertension.

Blood Pressure↗
PubMed1985

Sympathoadrenal responses to stress: the linking of type A behavior pattern to ischemic heart disease.

This report is an analysis of the findings of blood pressure, pulse rate, adrenergic and noradrenergic responses to laboratory and clinical stresses in subjects according to Type A and Type B behavior patterns. Thirty-three experiments of Type A - B cardiovascular and sympathoadrenal responses to a variety of laboratory stressors were identified. Twenty-nine of these were analyzed and the data of 20 were pooled to give mean values for the percentage increments of systolic and diastolic blood pressures, pulse rates, and plasma levels of NE and E for Type A vs B patients respectively; (15 +/- 2 vs 10 +/- 1, P less than .05; 13 +/- 1 vs 8 +/- 1, P less than .02; 19 +/- 2 vs 13 +/- 2, P less than .05, 60 +/- 11 vs 19 +/- 8, P less than .02; and 106 +/- 45 vs 23 +/- 12, P less than .1). Seventy-five percent of the analyzed experiments provided evidence for heightened cardiovascular and sympathoadrenal responsivity in Type A subjects. NE and E appear to be hormonal intermediates which play a lethal role in ischemic heart disease. Neutralization of neural tone may be an important goal in the therapy of hypertensives with Type A behavior pattern.

Adrenal Glands↗
PubMed1985

The role of stress and the sympathetic nervous system in hypertension and ischemic heart disease: advantages of therapy with beta-receptor blockers.

Human and animal studies link social and environmental factors to hypertension and ischemic heart disease. Job stress and undesirable life events may precede the development of raised blood pressure. Hypertension and ischemic heart disease vanquished many of the survivors of the seige of Leningrad. Specific behavior patterns of some patients with ischemic heart disease and the psychological ambience of others with hypertension have been associated with raised neural tone as reflected by levels of plasma norepinephrine and epinephrine. Sympathoneural hypertonicity is a factor in left ventricular hypertrophy and the latter has been a prophet for sudden cardiac death. Sympathoadrenal surges may contribute to both reduced coronary reserve in hypertensives and increased vulnerability to ventricular dysrhythmia. The "coronary epidemic" of our modern times appears related in part to outdated survival mechanisms, not suitable to human behavior in our urban milieu. Beta receptor blocking agents are effective antidotes providing protection from adrenomedullary overdrive and even perhaps, modification of that behavior. Stress and the sympathetic nervous system are important co-conspirators in hypertension and sudden cardiac death.

Adrenergic beta-Antagonists↗
PubMed1984

Central and peripheral noradrenergic tone in primary hypertension.

The contents of norepinephrine (NE), epinephrine (E), dopamine (DA), normetanephrine (NMN), and 4-hydroxy-3-methoxyphenylethylene glycol (MHPG) were measured in the plasma and cerebrospinal fluid (CSF) of 66 patients with primary hypertension and 24 patients with normal blood pressure and minor neurological disorders. Plasma and CSF NE and NMN concentrations were raised in the hypertensive patients. The plasma and CSF NE levels and arterial blood pressure of a small subset of hypertensive patients were normalized after clonidine therapy. In hypertensive patients the content of DA was lower and the ratio of NE/DA was greater; CSF and plasma NE contents were related to the level of arterial blood pressure; and the content of MHPG in CSF was linked strongly with NE content in plasma and CSF and to the level of arterial blood pressure. Thus both central sympathetic nerve tone and peripheral sympathetic nerve tone were enhanced in young patients with uncomplicated hypertension. The elevated levels of neurohormones and their metabolites in some patients with primary hypertension may be related to increased synthesis and release of neural NE and may be pathogenic in the blood pressure elevation.

Blood Pressure↗
PubMed1983

Long-term effectiveness of indapamide in hypertension: neural, renin and metabolic responses.

Indapamide conferred effective blood pressure control over the six-month period of study. Blood sugar was elevated slightly in some patients. Hypokalemia occurred commonly within four to six weeks of initiating therapy and was corrected with oral potassium supplementation. There were no changes in cholesterol or triglyceride. There was an increase in plasma renin activity, probably diuretic induced. The antihypertensive efficacy and the low side effect profile may both be related in part to the observed net reduction in neural tone.

Adult↗
PubMed1982

The relationships of free to conjugated normetanephrine in plasma and spinal fluid of hypertensive patients.

The concentrations of free and total normetanephrine (NMN) were determined in the plasma of normotensives and patients with primary hypertension and pheochromocytoma. NMN values were measured in the cerebrospinal fluid (CSF) of patients. Free and conjugated NMN, the latter after acid hydrolysis, were assayed using S-adenosylmethionine in the presence of phenylethanolamine-N-methyltransferase to form labeled metanephrine. The conjugates of NMN were present in plasma as sulfates principally, as they were also liberated with arylsulfatase. Free and conjugated NMN levels were 117 +/- 10 and 1417 +/- 109 ng/liter, respectively in plasma of normotensives. The mean ratio of the content of conjugated to free NMN was 14.9 +/- 1.8 (mean +/- SEM). The contents of free and conjugated NMN were 155 +/- 33 and 1670 +/- 320 ng/liter in primary hypertensives, respectively, and the ratio of conjugated to free NMN was 18.5 +/- 3.3. These values did not differ significantly from those in normotensives. The contents of free and total NMN in the plasma of patients with pheochromocytoma were 50- to 60-fold greater than values in normotensive and primary hypertensives. The mean ratio of conjugated to free NMN in the plasma of patients with pheochromocytoma was similar to those in normotensives and primary hypertensives. The contents of free and conjugated NMN in the CSF of patients with pheochromocytoma exceeded those in primary hypertensives (P less than 0.01 and P less than 0.001). Further, the ratio of conjugated to free NMN in CSF was increased in patients with pheochromocytoma (33.9 +/- 8.1) compared to that primary hypertensives (8.3 +/- 2.3; P less than 0.001). The measurement of NMN in plasma and CSF may help characterize sympathetic nerve tone in patients with primary hypertension to elucidate the pathophysiology of the elevated blood pressure.

Adolescent↗