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Biomedical subjects

G Covi

Publications and source records attributed to G Covi.

At least 37 records · Page 2Linked to original sources
PubMed1984

Faecal lipid chromatography. I. Quantitative determination with chromarods.

A new and original method is proposed for the qualitative and quantitative analysis of faecal lipids by thin-layer chromatography and detection through the flame ionization detector of an analyser (the Iatroscan TH 10). This method enables the rapid quantification of the different faecal lipid classes, including cholesterol, with great accuracy and reproducibility. In-series operations are possible with easy manipulation.

Chemical Phenomena↗
PubMed1984

Fecal lipid chromatography--identification of an unusual fraction in relation to colon cancer.

The thin-layer chromatography of fecal lipids with revelation by phosphomolybdic reagent indicates the presence of an unusual fraction only in colon cancer patients. After isolation and identification, this fraction appears to be composed of coprostanol and its derivatives. The quantitative analysis of fecal neutral steroids in colon cancer patients compared to controls, patients with other digestive diseases and polypi shows a positive relationship between this fraction and colon cancer.

Adult↗
PubMed1984

Reduction of the antihypertensive effect of captopril induced by prostaglandin synthetase inhibition.

The effects of prostaglandin synthetase inhibition by indomethacin on blood pressure and hormonal variations induced by captopril were studied in eight patients with essential hypertension and in six nonhypertensive subjects. Captopril antihypertensive effect and captopril-induced plasma renin increase were almost totally abolished by a short-term administration of indomethacin (50 mg t.i.d.). These results support the hypothesis that prostaglandins contribute to the antihypertensive effects of ACE inhibitors. It may be of clinical importance that anti-inflammatory drugs that inhibit PG-synthetase can also blunt the antihypertensive action of ACE inhibitors.

Adult↗
PubMed1983

A discrepancy between the effects of a single oral dose of captopril on blood pressure, plasma renin activity, and serum angiotensin-converting enzyme levels.

The effects of a single oral dose (100 mg) of the angiotensin-converting enzyme (ACE) inhibitor, captopril (SQ 14,224), on blood pressure (BP), plasma renin activity (PRA), plasma aldosterone (PA), and serum ACE were investigated in 18 patients with essential hypertension (EH) and in 4 with renovascular hypertension (RVH). in most patients, SQ 14,225 caused a significant reduction of BP during the subsequent 6 h, particularly in RVH patients. A significant correlation between basal PRA levels and BP reduction was observed only by considering all the patients together. After ACE blockade, a significant increase of PRA was observed in RVH and in normal-renin EH patients, but not in EH patients with lower PRA. Maximal serum ACE inhibition (over 50%) occurred after 2 h but diminished after 4 h and 6 h, whereas the BP decrease persisted for 6 h. After 3-day treatment with indomethacin (six patients) captopril's antihypertensive action was blunted, despite a reduction of baseline PRA levels and of captopril-induced PRA elevation. The antihypertensive effects of SQ 14,225 in low-renin EH patients, the lack of effect of ACE blockade on renin secretion in these patients, and the reduction of the antihypertensive effects of SQ 14,225 after indomethacin refute the interpretation of purely angiotensin-related antihypertensive mechanism.

Administration, Oral↗
PubMed1981

Intravenous labetalol in severe hypertension. Effects on blood pressure, plasma renin activity and catecholamines.

2-Hydroxy-(1-hydroxy-[(1-methyl-3-phenylpropyl)amino]-2-ethyl)-5-benzamide (labetalol), a new alpha- and beta-adrenergic blocking agent, was employed in 21 patients with severe hypertension by slow (6 patients) and rapid (15 patients) i.v. infusion. A marked and significant fall of blood pressure was observed in both groups, though more gradual in patients treated by slow infusion. A rapid blood pressure fall with cardiac output decrease was observed by passing from supine to standing position in the first hours after infusion. Therefore, it is advisable to keep a supine position for a few hours. Plasma renin activity decreased after labetalol infusion, but basal plasma renin levels were not related to hypotensive effect of labetalol. In slow infusion patients, plasma noradrenaline levels increased and no changes of plasma adrenaline levels were observed during infusion. The most likely explanation of these variations is an increase of sympathetic activity secondary to hypotension, caused by labetalol, whereas a technical interference seems to be excluded. The simultaneous blockade of alpha- and beta-receptors can inhibit, in this case, the pressor effects of the sympathetic reflex.

Adult↗
PubMed1979

Multicentre comparative trial of tienilic acid and hydrochlorothiazide in hypertensive patients.

To compare the clinical and metabolic effects of a new diuretic uricosuric agent, tienilic acid, with those of hydrochlorothiazide, a multicentre double-blind trial was performed in 56 hypertensive patients. Twenty-eight patients were randomly assigned to take tienilic acid and 28 to take hydrochlorothiazide. The diuretic and anti-hypertensive actions of the two compounds were similar. No significant differences were observed between tienilic acid and hydrochlorothiazide in their effects on urinary and serum electrolytes, hepatic and renal function tests, and fasting lipids. The patients who received tienilic acid showed a significant fall in serum uric acid, mediated by the uricosuric effect. The availability of an agent combining diuretic, antihypertensive and hypouricemic effects offers promise in the treatment of arterial hypertension.

Adolescent↗
PubMed1979

An evaluation of tienilic acid, a new diuretic uricosuric agent, in the therapy of arterial hypertension.

1. Tienilic acid and hydrochlorothiazide were evaluated in a double-blind trial in order to investigate their antihypertensive and metabolic effects. 2. After 5 weeks, the decreases in blood pressure and the changes in plasma or serum electrolytes, urea, creatinine, glucose, cholesterol and triglycerides, and in creatinine clearance, did not differ in the two groups of patients. 3. In patients taking tienilic acid a significant decrease in serum uric acid and an increase in urate clearance was observed, whereas in patients receiving hydrochlorothiazide a slight increase in serum uric acid, with no modification of urate clearance, occurred. 4. The diuretic and antihypertensive actions of tienilic acid and hydrochlorothiazide are very similar. The uricosuric/hypouricaemic effect of tienilic acid could assume clinical relevance in long-term therapy of hypertensive patients.

Adolescent↗
PubMed1978

Urinary kallikrein excretion and plasma renin activity in patients with essential hypertension and primary aldosteronism.

1. The 24 h urinary excretion of kallikrein has been studied in 40 normotensive control subjects and in 74 age-matched patients with essential hypertension under similar conditions. By use of the renin-sodium index, hypertensive patients were divided into two subgroup: low-renin hypertension and normal-renin hypertension patients. Urinary kallikrein determinations were also obtained from six hypertensive patients with primary aldosteronism. 2. Urinary kallikrein was significantly lower both in patients with normal-renin and low-renin essential hypertension. Urinary kallikrein excretion was very high in the patients with primary aldosteronism. 3. In nine hypertensive patients beta-adreno-receptor-blocking therapy caused a significant decrease of plasma renin activity, but had no significant effect on urinary kallikrein excretion. 4. The results support the concept that low urinary kallikrein is likely to be a marker of essential hypertension. Under certain conditions its excretion is positively related to mineralocorticoid hormone concentrations but it is not primarily related to the renin-angiotensin system.

Adult↗
PubMed1976

Urinary and kidney kallikrein in hypertensive rats.

Urinary and kidney kallikrein were studied in rats with renal clip hypertension. The effect of protease inhibitors on urinary and kidney BAEE esterase activity was similar. Both hypertensive and not hypertensive operated rats excrete significantly less kallikrein than controls; in the ischaemic kidney kallikrein is diminished whereas is not increased in contralateral. Kallikrein is therefore related to renal functional mass but does not seem responsible for a natriuretic effect.

Animals↗
PubMed1976

Urinary kallikrein excretion in Bartter's syndrome.

Urinary excretion of kallikrein has been studied in a patient with hypokalemic alkalosis, hyperplasia of the renal juxtaglomerular apparatus and hyperreninemia, secondary aldosteronism and resistance to the pressor effect of angiotensin II (Bartter's syndrome). Urinary kallikrein was found exceedingly high in several determination, whereas it was low in patients with essential hypertension and high in patients with primary aldosteronism. Urinary kallikrein decreased after spironolactone therapy. The rise of kallikrein excretion (which is not related to plasma renin) in this case is probably caused by a direct action of the chronic excess of plasma aldosterone; it could not be accounted for as secondary to natriuresis.

Adult↗
PubMed1976

Measuring water content of feces by the Karl Fischer method.

We describe a technique for measuring the water content of stools by the Karl Fischer method. The analysis is based on removal of water into a mixture of methanol/chloroform (1/2), after dispersion of the stool by sonication in presence of solvent. An aliquot of the solution thus obtained is placed in themeasuring cell of a Karl Fischer apparatus and then analyzed in the classic way. We further describe the advantages of this method (odorless, precise, reproducible) in contrast to other current methods. In addition the same organic solution can also be used in determining the lipid content of stools.

Color↗