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Biomedical subjects

V DeQuattro

Publications and source records attributed to V DeQuattro.

At least 73 records · Page 4Linked to original sources
PubMed1982

Raised plasma catecholamines in old and young patients with disproportionate systolic hypertension.

Sympathetic nerve tonicity was assessed in hypertensives with either proportionate or disproportionate elevation of systolic blood pressure: patients were segregated into two groups, age less than 40 years and age 40 years and greater. Plasma catecholamines of sixty patients with proportionate hypertension and thirty five with disproportionate hypertension were compared with those of sixty one age matched normotensive volunteers. Disproportionate patients were younger than proportionate hypertensives in the age group less than 40 years (p less than .01) and were older than proportionate in the 40 years and older group (p less than .01). The youngest and oldest patients with disproportionate systolic hypertension tended to have normal diastolic blood pressure. Total plasma catecholamines were increased in both groups of hypertensives, whether young or old. However, only values in male hypertensives were increased significantly when compared with normotensives (p less than .01). Enhanced sympathetic nervous system tonicity appears to be an important factor in the cause and maintenance of both proportionate and disproportionate systolic hypertension.

Adolescent↗
PubMed1982

Paragangliomatosis with numerous catecholamine-producing tumors.

Catecholamine-producing tumors may be found wherever paraganglion tissue exists, and they may be associated with a variety of conditions (multiple endocrine neoplasia types 1, 2a and 2b). The patient described in this report had 21 paragangliomas removed between the ages of 13 and 17 years, and she has evidence of additional tumors. This is the greatest number of paragangliomas reported, and the tumors involved numerous sites. In addition, the patient has multiple congenital anomalies that have not been reported previously in association with paraganglioma. Unifying theories of pathogenesis and several features in the management of this patient are discussed.

Abnormalities, Multiple↗
PubMed1981

Anger, anxiety, guilt and increased basal and stress-induced neurogenic tone: causes or effects in primary hypertension?

1. Basal plasma and spinal fluid noradrenaline were increased in patients with primary hypertension and phaeochromocytoma compared with normotensive patients (P less than 0.01). 2. Patients with primary hypertension had more anger (P less than 0.01), anxiety (P less than 0.01) and guilt (P less than 0.05) than normotensive patients or patients with phaeochromocytoma. 3. The responses of noradrenaline and adrenaline concentrations were similar after mental and isometric stress in primary hypertensive and normotensive subjects. 4. However, after mental stress and isometric exercise there were increased responses of plasma noradrenaline and systolic blood pressure respectively, in patients with high anxiety and anger compared with those below the 50th percentile (P less than 0.05). 5. Increased central and peripheral neurogenic tone at rest and after stress in association with increased anxiety and suppressed anger appear to be pathogenic factors in some patients with primary hypertension and may not be a result of the blood pressure elevation.

Adrenal Gland Neoplasms↗
PubMed1980

Central and regional normetadrenaline in evaluation of neurogenic aspects of hypertension: aid to diagnosis of phaeochromocytoma.

1. Free normetadrenaline concentrations in plasma of patients with phaeochromocytoma were elevated 20-1000-fold as compared with values in primary hypertensive subjects. 2. Spinal fluid normetadrenaline was 1.8-16% of the simultaneous plasma values in patients with phaeochromocytoma, whereas levels in spinal fluid exceeded those of plasma in primary hypertension. 3. Spinal fluid noradrenaline was 7.9-58% of simultaneous values of plasma noradrenaline in patients with phaeochromocytoma, whereas values in plasma and cerebrospinal fluid were similar in primary hypertension. 4. Plasma noradrenaline and normetadrenaline levels were both elevated in veins from regions subsequently found to harbour chromaffin tumours. 5. The excessive amounts of normetadrenaline produced in phaeochromocytoma enters plasma but not spinal fluid and can be used for diagnosis and localization of phaeochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1980

Long-term effects of minoxidil therapy on renal function of patients with refractory hypertension: the significance of albuminuria.

The addition of minoxidil therapy reduced blood pressure effectively for 6--52 months (average, 24) in 25 of 28 patients with refractory hypertension. One patient was nonresponsive; 2 were noncompliant. Patients who had a serum creatinine up to 4 mg% and greater than 750 mg of albuminuria per day had further deterioration of renal function of 5.3 +/- 1.4% per month compared to that of 0.2 +/- 0.4% per month in patients without albuminuria (p less th5% was not as helpful predicting preservation of renal function in patients with refractory hypertension after adding minoxidil as was the absence of albuminuria.

Adult↗
PubMed1980

Relationship between plasma catecholamines, plasma renin activity, aldosterone, and arterial pressure during postural stress in normal subjects.

The relationship between plasma catecholamines, PRA, aldosterone, and MBP in the supine and upright positions and after furosemide were studied in 44 normal subjects. Supine plasma NE correlated with MBP (r = 0.52, p greater than 0.01) and with age (r = 0.57, p greater than 0.01). The partial correlation coefficient of plasma NE with MBP controlling for age was r = 0.40, p greater than 0.025. These data suggest that the sympathetic nervous system plays an important role in the maintenance of blood pressure during the supine position. With upright posture, plasma NE and E, PRA, and plasma aldosterone increased significantly, whereas urinary sodium excretion decreased and urinary excretion of NE did not change.

Adolescent↗
PubMed1979

Treatment of severe hypertension with minoxidil: advantages and limitations.

Minoxidil, a new peripheral vasodilator, was used in the therapy of 26 hypertensives who were previously uncontrolled on conventional medications or who had dose-limiting side effects. Minoxidil provided (1) therapeutic advantages in all patients, regardless of the etiology of their hypertension, (2) no symptoms of orthostatic hypotension or sympathetic nervous system depression, (3) a simplification of medical regimens and perhaps costs, and (4) regression of impotence in four out of seven patients. The major limiting factors encountered were (1) fluid retention with the development of congestive heart failure in three patients, (2) pericardial effusion in three patients, and (3) hypertrichosis, which reduced its acceptability in female patients.

Adult↗
PubMed1978

Clinical assessment of sympathetic tone: orthostatic blood pressure responses in borderline primary hypertension.

Orthostatic changes of systolic, diastolic and pulse pressure, and pulse rates were evaluated as clinical indicators of sympathetic nerve tone in 28 patients with uncomplicated primary hypertension. After sixty minutes in the upright position, systolic blood pressure increased in 13 and decreased in 15 of the patients, while pulse pressure diminished in 19, was unchanged in 4 and increased in 5 of the patients. The changes of both systolic blood pressure and pulse pressure showed a significant positive correlation with basal (supine) levels of norepinephrine (r = 0.40, p less than 0.05 and r = 0.54, p less than 0.01, respectively). In the total sample of patients, 25% had basal plasma norepinephrine concentrations above the normal range. Of the patients with increased systolic blood pressure after standing, 38% had elevated basal norepinephrine. Similarly in patients with increased orthostatic pulse pressure or in those with pulse pressure reductions less than 10 mm Hg, 45% had elevated basal norepinephrine. On the other hand, of patients with reductions of pulse pressure of more than 10 mm Hg, only 6% had elevated basal norepinephrine. Of the patients with similar systolic blood pressure reductions, none had increased plasma norepinephrine. Both diastolic blood pressures and pulse rates always rose during orthostatic stress, but they did not correlate with basal sympathetic tone. In conclusion, hypertensive patients with orthostatic increases of systolic and pulse pressure are more likely to have elevated basal sympathetic tone than unresponsive patients. The former may comprise a subset of hypertensives who have a causal neurogenic component. They may be more sensitive to drugs which suppress sympathetic nerve function.

Adolescent↗
PubMed1978

The determinants of plasma-renin activity in essential hypertension.

Plasma-renin activity was studied, under different conditions of sitmulation, in normal subjects and patients with essential hypertension. In normal subjects, three components of renin release, "basal," "neural," and "sodium-sensitive," could be delineated. Among the hypertensive patients, abnormal patterns of renin release were noted. The categorization of patients according to "plasma-renin status," however, differed with the conditions of testing, being dependent both on the pathophysiology of the essential hypertension and the character of the renin-releasing stimulus, specifically whether this stimulus elevated plasma-renin activity through a predominantly neural (upright posture) or non-neural mechanism (dietary sodium deprivation). Abnormal plasma-renin activity in essential hypertension resulted in part from disordered sympathetic nervous system function. Patients with mild hypertension and elevated plasma-renin activity exhibited increased neural stimulation of renin release, whereas in patients with low plasma-renin values, all three components of renin release, including the neural element, were diminished.

Adolescent↗
PubMed1977

Mild high-renin essential hypertension. Neurogenic human hypertension?

To determine whether the elevated plasma renin activity in some cases of mild essential hypertension expresses sympathetic-nervous-system over-activity, we compared indexes of sympathetic activity in 16 patients with mild high-renin essential hypertension, 15 hypertensive patients with normal plasma renin activity and 20 normal subjects. Patients with elevated activity exhibited a raised plasma norepinephrine concentration (P less than 0.05), a greater fall in cardiac output with cardiac beta-adrenergic blockade by intravenous propranolol (P less than 0.01), reduction in total peripheral vascular resistance with alpha-adrenergic blockade produced by intravenous phentolamine (P less than 0.01), and reduction to normal of blood pressure by "total" autonomic blockade (atropine, propranolol and phentolamine). On psychometric testing, patients with high-renin hypertension, but not those with normal plasma renin activity, exhibited suppressed hostility (P less than 0.01), a behavioral pattern linked to increased sympathetic activity. The hypertension in these patients with high renin activity is neurogenic and possibly psychosomatic in origin.

Adolescent↗
PubMed1977

Pathophysiologic and pharmacokinetic determinants of the antihypertensive response to propranolol.

The tendency for patients with essential hypertension to differ markedly in antihypertensive response to propranolol could arise from pathophysiologic or pharmacokinetic differences between them. This possibility was investigated in 23 men with mild to moderately severe essential hypertension. At each of three propranolol doses, 40 mg, 80 mg, and 320 mg daily, approximately a 20-fold range in steady-state plasma propranolol concentrations was observed. Clinical response however was unrelated to plasma propranolol: oral dose ratio, since patients with higher plasma levels were less sensitive to the existing plasma drug concentration. When falls in blood pressure and plasma propranolol concentration were compared overall, a biphasic dose-response relationship was noted, with a first component at plasma propranolol concentrations of 3 to 30 ng/ml and a second at concentrations above 30 ng/ml. Only patients with increased sympathetic nervous system activity and high plasma renin activity (PRA) had substantial falls in pressure at propranolol levels of 3 to 30 ng/ml. Cardiac beta adrenergic receptor blockade, not suppression of PRA, seemed to be the antihypertensive mechanism. This relation of pretreatment sympathetic nervous activity and PRA to antihypertensive response existed only at lower plasma propranolol concentrations. With a propranolol dose of 320 mg daily, both plasma norepinephrine concentration and PRA were unrelated to the clinical response.

Adolescent↗
PubMed1977

Childhood pheochromocytoma: treatment with alpha methyl tyrosine for resistant hypertension.

A 12-year-old boy with a norepinephrine-secreting pheochromocytoma that caused hypertension resistant to oral alpha adrenergic blockade is reported. Resistance to alpha adrenergic blocking agents developed when the patient's daily propranolol dosage was lowered from 10 to 1 mg/kg. Subsequently, alpha methyl tyrosine, an inhibitor of tyrosine hydroxylase, the rate-limiting enzyme in catecholamine biosynthesis, controlled the patient's blood pressure and was associated with reduction in total urinary catecholamine excretion. Norepinephrine content of the tumor and uninvolved adrenal gland removal at surgery was reduced. These findings confirm that alpha methyl tyrosine inhibited in vivo synthesis of catecholamines.

Adrenal Gland Neoplasms↗
PubMed1977

Sympathetic nerve hyperactivity in high-renin hypertension effects of saralasin infusion.

We found increased levels of catecholamines in some patients who had high-renin hypertension. To study relations between angiotensin and the sympathetic nerves further, we infused saralasin, a blocker of angiotensin II, into 11 hypertensive patients being evaluated for renovascular hypertension. There were variable responses of mean arterial pressure, plasma renin activity, and norepinephrine levels. When high-renin hypertensive patients with increased levels of norepinephrine were compared with those having high renin and normal levels of norepinephrine, they showed a lesser decrease in mean arterial pressure--5 +/- 5% versus 14 +/- 4%, P less than 0.05--a decrease in plasma renin activity of 20 +/- 17% versus an increase of 77 +/- 24% (P less than 0.01), and a decrease in norepinephrine levels of 42 +/- 7% versus an increase of 10 +/- 23% (P less than 0.05) (means +/- SE). The evidence suggests that patients with high-renin levels are heterogeneous and that the primary mediator of the hypertension is sympathetic tone hyperactivity in those with increased levels of norepinephrine and angiotensin excess in those with normal levels of norepinephrine.

Adolescent↗
PubMed1977

Agreement among three different indices of sympathetic nervous system activity in essential hypertension.

Although plasma norepinephrine concentration often is elevated in patients with essential hypertension, the relevance of this to the pathogenesis of the blood pressure elevation remains uncertain. If the high concentration of plasma norepinephrine truly indicates sympathetic nervous system overactivity, it should be accompanied by hemodynamic features suggestive of sympathetic cardiovascular stimulation. This proposition was tested, and in part confirmed, in a study performed on 21 patients who had mild essential hypertension and on 11 normal subjects. Among hypertensive patients, plasma norepinephrine concentration was related to cardiac function but not to the level of the blood pressure or to total peripheral vascular resistance. Plasma norepinephrine concentration correlated significantly with heart rate and cardiac preejection period index at rest and with changes in cardiac output, heart rate, and preejection period after cardiac beta-adrenergic blockade produced by propranolol, 0.2 mg/kg intravenously. Patients with an elevated plasma norepinephrine concentrations (9 of 21) showed features of sympathetic cardiac stimulation, manifested by an elevated mean cardiac index and heart rate at rest and by normalization of both after treatment with propranolol. Thus, substantial agreement existed among three commonly used indices of sympathetic nervous system activity--plasma norepinephrine concentration, general hemodynamics at rest, and the hemodynamic response to pharmacologic autonomic blockade.

Adolescent↗