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Biomedical subjects

A Foti

Publications and source records attributed to A Foti.

At least 37 records · Page 2Linked to original sources
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

Effects of clonidine on central and peripheral nerve tone in primary hypertension.

To define the mechanisms whereby clonidine lowers blood pressure, we measured cerebrospinal fluid and plasma levels of norepinephrine, normetanephrine, epinephrine, dopamine, and the dopamine metabolite homovanillic acid in 10 primary hypertensive subjects before and after 3 months of clonidine treatment (mean dose, 0.68 mg/day). Catecholamines were measured by radioenzymatic methods. Cerebrospinal fluid and plasma sampling was performed after subjects had fasted and remained supine overnight, and plasma sampling was repeated 2 hours later, after subjects had ambulated. Supine and upright blood pressure fell, as might be expected. Cerebrospinal fluid levels of norepinephrine and normetanephrine fell significantly, but dopamine and homovanillic acid levels were unchanged. Plasma norepinephrine, normetanephrine, and epinephrine levels decreased 30 to 50%, and supine dopamine levels also fell. The percent fall in supine blood pressure was related to the fall of cerebrospinal fluid and plasma norepinephrine. There were also positive relationships between the decreases of plasma norepinephrine and of normetanephrine and dopamine. The cerebrospinal fluid/plasma norepinephrine ratio was unaffected by clonidine, suggesting that the drug lowered both pools equally. Our findings indicate that clonidine decreases both central and peripheral norepinephrine activity. The dopaminergic activity of cerebrospinal fluid was unaffected by clonidine, and though plasma dopamine levels tended to be lower after treatment, mean plasma prolactin level, an index of dopaminergic activity, was also unchanged. The fall in plasma epinephrine level is probably related to diminished sympathetic adrenomedullary stimulation and is unlikely to contribute to clonidine's antihypertensive action. These results also suggest that measurement of normetanephrine in cerebrospinal fluid and plasma provides a good index of norepinephrine activity.

Adult↗
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↗
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↗
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↗
PubMed1981

Changes in plasma and cerebrospinal fluid electrolytes in hypercapnia.

A study on two groups of patients in acute respiratory failure with hypercapnia (18 subjects) and in hypercapnic coma (18 subjects) has been carried out to determine the related changes in sodium ion, potassium ion, chloride ion, urea and osmolality in blood and cerebrospinal fluid. There were significant differences between the two pathological states and particularly in coma, changes in transmembrane active transport of electrolytes are significantly related to high concentrations of CO2 in the brain.

Carbon Dioxide↗
PubMed1981

[Anesthesiological problems in tracheal resection operations. Clinical contribution].

The anaesthesia technique adopted for tracheal resection in a woman patient with tracheal stenosis secondary to prolonged intubation is reported. The criteria underlying the choice of anaesthesia are outlined. Various anaesthesiological techniques are discussed and solutions illustrated in relation to the location of tracheal stenosis.

Anesthesia↗