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Biomedical subjects

S Cottone

Publications and source records attributed to S Cottone.

46 records · Page 3Linked to original sources
PubMed1987

Effects of enalapril maleate on blood pressure, renin-angiotensin-aldosterone system, and peripheral sympathetic activity in essential hypertension.

Recent experimental studies showed that inhibition of angiotensin II synthesis may reduce sympathetic activity as evaluated by plasma catecholamine assay, sharing in the antihypertensive effect of angiotensin converting enzyme (ACE) inhibitors. Fifteen patients with essential hypertension were studied. Blood pressure and heart rate were evaluated both at rest and after stressor laboratory tests, before and four hours after administration of 20 mg of enalapril maleate and on the 14th and 120th days of continued administration. At the same time, blood samples were drawn for determinations of plasma renin activity, ACE, angiotensin II, plasma aldosterone concentration, and plasma norepinephrine levels. Enalapril in a dosage of 20 mg/day significantly and progressively lowered systolic and diastolic blood pressure at rest, with maximal decreases observed on the 120th day of the study period (P less than 0.001). Heart rate at rest and after exercise showed no significant differences throughout the study period. Good blood pressure control was observed during stressor laboratory tests. The greatest impact of blood pressure was observed on the 120th day during dynamic exercise (mean blood pressure from 139 +/- 3.9 to 111.5 +/- 6.3 mmHg; P less than 0.01) and on the 14th day during the cold pressure test (mean blood pressure from 133.3 +/- 3.9 to 111.2 +/- 4.7 mmHg; P less than 0.005). A marked and persistent ACE inhibition and a gradual and progressive decrease of angiotensin II (from 12.42 +/- 2.15 to 5.45 +/- 1.68 pg/ml; P less than 0.005) characterized the humoral activity of enalapril maleate. Moreover, a significant decrease of plasma norepinephrine levels was observed during the follow-up period with maximal reduction on the 120th day (from 311 +/- 34 to 197 +/- 33 pg/ml; P less than 0.01). It has been demonstrated that the pressor effect of angiotensin II was blunted during exercise. Our hemodynamic and humoral results appear to confirm the hypothesis that enalapril maleate may reduce blood pressure by direct inhibition of ACE and of kininase II as well as by a decreased sympathetic output, which may be secondary to angiotensin II inhibition. These results agree with the recent experimental demonstration of a reduced sympathetic nervous response to nerve stimulation during ACE inhibition.

Adult↗
PubMed1987

Role of epinephrine in the development of essential hypertension.

Recently, it has been showed that Epinephrine (E) plays an important role in the pathogenesis of essential hypertension in rats. Furthermore, some literature data demonstrated the existence of high E plasma levels at rest and after stress in essential hypertension. To evaluate the sympatho-adrenal activity, both in basal condition and after stress, and its relationship with the renin-angiotensin-aldosterone (RAA) system, 31 borderline hypertensives (BH), 30 essential hypertensives (EH), and 15 healthy subjects were studied. After a wash-out period and electrolyte evaluation, all subjects were studied at rest, during dynamic exercise, and after 30 minutes of recovery; at the same time blood pressure and heart rate were automatically recorded and blood samples were collected for plasma renin activity (PRA), E, Norepinephrine (NE) and aldosterone plasma concentrations assay. BH showed a percentage increase of mean blood pressure greater than EH (p less than 0.01) during dynamic exercise. PRA showed no significant differences between the 3 groups examined at rest; on the contrary, PRA levels and the percentage increases were significantly higher in BH than in EH (p less than 0.05 respectively). E plasma levels and its percentage increases were significantly greater in BH than both in EH (p less than 0.05) and in controls after exercise. Furthermore, raised E plasma levels lasted significantly throughout the recovery period (p less than 0.05) only in BH. A significant correlation between both E plasma levels and percentage increases with NE percentage increases was observed after exercise in BH. Our results demonstrate a sympatho-adrenal overactivity in borderline hypertension, which is characterized by a prolonged E hyper-responsiveness, a renin hyper-secretion and a high hemodynamic response to stress. In borderline hypertension, E, excessively released from the adrenal gland, may act as a sympathetic cotransmitter inducing functional adrenoceptors hyperactivity.

Adolescent↗
PubMed1984

The relationship between potassium balance and circulating catecholamines in essential hypertension.

A study of neuroendocrine trend and electrolytes balance was carried out in 29 patients with essential hypertension and 20 normotensive controls. Based on plasma norepinephrine (NE) resting values to subgroups of hypertensives were defined, one in the "normal" range (NE less than 268 pg/ml) and one in the "high" range (NE greater than 268 pg/ml). In response to graded exercise the "high" NE hypertensive patients showed a mean NE increase significantly higher than both normal controls and "normal" NE hypertensives (p less than 0.05). No significant differences in the electrolytes excretion rates were found between the two subsets, but only in the hyper-noradrenergic hypertensives a negative correlation between potassium excretion and circulating NE levels was observed (r = -0.68; p less than 0.005). These findings suggest that in the hypertensive population there is a not negligible proportion of patients with elevated NE levels under basal conditions which are, moreover, hyper-responsive to stressful situations. This abnormal sympathetic function could be probably related to the state of potassium balance.

Adolescent↗
PubMedDate not supplied

Effects of dynamic exercise and metabolic control on left ventricular performance in insulin-dependent diabetes mellitus.

In subclinical diabetic cardiomyopathy, previous reports did not positively correlate the altered cardiac performance with metabolic parameters. Fifteen insulin-dependent diabetic subjects, without any clinical or instrumental evidence of heart diseases, were studied. Signs of diabetic microangiopathy were absent. Systolic time intervals, metabolic and hormonal parameters (blood glucose, free fatty acids, blood lactate and plasma norepinephrine) were evaluated at rest and after dynamic exercise during poor (MAGE 6.36 +/- 0.72 mmol/l) and good (MAGE 3.46 +/- 0.66 mmol/l) metabolic control, obtained by means of insulin therapy. Rest values of systolic time intervals were normal during poor and good metabolic control. After exercise, pre-ejection period/left ventricular ejection time ratio increased mainly during poor control as a result of an increased pre-ejection period: conversely, a smaller increase in pre-ejection period/left ventricular ejection time ratio occurred during good metabolic control. The exercise induced free fatty acids utilization did not occur during poor control as it occurred during good control. The percentage of increments in blood lactate was virtually identical in ketotic and non-ketotic patients and in normal subjects. High norepinephrine plasma levels were observed both at rest and during dynamic exercise in poorly controlled diabetic patients. Conclusively, testing of systolic time intervals after exercise might be useful in the detection of preclinical diabetic cardiomyopathy. The decreased cardiac functional reserve observed during poor control might be related to an altered energetic fuel utilization.

Adult↗
PubMedDate not supplied

Rifaximine versus neomycin in the treatment of portosystemic encephalopathy.

In 14 patients with cirrhosis and chronic portosystemic encephalopathy, the effectiveness of treatment with a new non-assorbable antibiotic (rifaximine) was compared to neomycin. The parameters evaluated were: bradylalia, flapping tremor, performance, visual evoked potentials and the trial making test. Both treatments were combined with lactulose. The analysis of results showed a rate of positive results in the patients treated with rifaximine greater than that with neomycin. Differences, however, were not significant.

Chronic Disease↗
PubMedDate not supplied

[Microalbuminuria, an early marker of renal changes in essential hypertension].

The purpose of this study was to verify if microalbuminuria (AER) could be an early feature of renal hemodynamic changes in essential hypertension. Fifty-three patients with newly diagnosed essential hypertension (EH) underwent 24-hour blood pressure monitoring (24h-BP). Furthermore, AER and glomerular filtration rate (GFR) were evaluated by obtaining 24-hour urine collection: day- and night-time urine was kept separate. Data from the 53 EH patients were analyzed both collectively and after subdivision into two subgroups based on AER values (less or more than 16 micrograms/min). In the 53 EH patients, 24h-AER correlated significantly to both 24h systolic and diastolic blood pressure (BP) (r = 0.58 and 0.67, respectively). The subgroup with AER greater than 16 micrograms/min showed higher values of 24h-BP and GFR than the other subgroup. Moreover, in the first subgroup, 24h-systolic BP (r = 0.61) and 24h-diastolic BP (r = 0.68) correlated with AER. Our data seem to indicate that among the hypertensive patients, there is a subgroup of subjects whose hypertensive disease is characterized by high blood pressure as well as elevated microalbuminuria and glomerular filtration rate values. Increased microalbuminuria in newly diagnosed hypertensive disease seems to be due to glomerular hypertension and early altered microvascular permselectivity, and would thus indicate an early clinical expression of altered renal hemodynamics.

Adult↗
PubMedDate not supplied

Treatment of malignant hypertension with an angiotensin converting enzyme inhibitor.

Malignant hypertension developed in an 18-year-old man whose primary hypertension had been diagnosed by chance. Standing blood pressure was 290/170 mmHg. Tests of renal function revealed high blood urea nitrogen and creatinine levels and low levels of both effective renal plasma flow and the glomerular filtration rate. Plasma renin activity and levels of angiotensin II and aldosterone were greatly elevated. Severe concentric left ventricular hypertrophy was noted. The patient received standard antihypertensive treatment with furosemide, propranolol, nifedipine, and prazosin, but his blood pressure did not decrease and there was no improvement in the clinical or biochemical measures. The patient was then given 20 mg of enalapril daily for one year. The inhibition of angiotensin converting enzyme immediately reduced blood pressure. Angiotensin II and aldosterone levels became normal, kidney function and hemodynamics improved, and echocardiograms revealed that the left ventricular hypertrophy had regressed. The results confirm the pathogenetic role of angiotensin II in the development of the malignant phase of hypertension.

Adolescent↗