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Biomedical subjects

S Marchi

Publications and source records attributed to S Marchi.

At least 73 records · Page 4Linked to original sources
PubMed1987

Amiodarone and desethylamiodarone tissue uptake in rats chronically treated with amiodarone is non-linear with the dose.

Four groups of rats were given amiodarone chronically at 25, 37.5, 50, 75 mg kg-1/12 h for 3 weeks; on day 21 the animals were killed and blood, plasma, heart, lung, liver and fat were collected and assayed for amiodarone and desethylamiodarone. Amiodarone plasma concentrations ranged from 0.74 to 4.68 micrograms mL-1 and desethylamiodarone from 0.08 to 2.05 micrograms mL-1. Plasma, blood and tissue concentrations of amiodarone and desethylamiodarone increased significantly with the dose. Blood/plasma and tissue/plasma partition ratios of amiodarone and desethylamiodarone increased significantly at the higher doses. Blood/plasma ratio was a good predictor of tissue/plasma ratios of amiodarone and its metabolite, except in fat. Total phospholipid concentrations in lung were correlated with amiodarone and desethylamiodarone concentrations in plasma, blood and lung.

Amiodarone↗
PubMed1986

[Hepatic iron and chronic alcoholic liver disease. Histochemical findings].

Histochemical methods (Perls-Turnbull-Blan) were used to assess the amount of iron present in the liver tissue (needle biopsy) of patients in various stages of chronic alcoholic liver pathology. The highest iron titres were found in the patients at the most advanced stage of the disease and there appeared to be a correlation between the size of the anatomopathological alterations and the quantity of haemosiderinic pigment.

Biopsy↗
PubMed1986

Slow intravenous administration of low dose aspirin inhibits both vascular and platelet cyclooxygenase activity: an experimental study in the rat.

Aspirin irreversibly inhibits cyclooxygenase, thus preventing thromboxane (Tx)A2 production in platelets and prostacyclin in vascular cells. While it is generally accepted that the inhibitory effect of low dose aspirin is cumulative on platelet cyclooxygenase, it is still a matter of debate whether a similar phenomenon also occurs on vascular cyclooxygenase. We have measured in anesthetized rats the inhibitory effect of two doses of aspirin (2.5 and 5.0 mg/kg), given intravenously either as a bolus or as a continuous infusion (for 30 min), on platelet TxB2 and 6-ketoprostaglandin F1 alpha generation by different vascular segments. Aspirin significantly inhibited both platelet and vascular cyclooxygenase independently of the rate of drug administration. The aspirin peak plasma levels at the end of bolus injection was about 170 times higher than the average level measured during the slow infusion (1.21 +/- 0.15 micrograms/ml). At this concentration aspirin did not affect in vitro either platelet or vascular cyclooxygenase activity. Thus the inhibitory effect of aspirin on both platelet and vascular cyclooxygenase seems to be related to total exposure of the enzyme to the drug rather than to the maximal drug concentration attainable in the systemic circulation. These findings may be relevant to the current debate on optimal conditions for the biochemical selectivity of aspirin as an antithrombotic drug.

Animals↗
PubMed1986

Pirenzepine versus ranitidine in gastroprotection during antiblastic chemotherapy: a double-blind study.

Corticosteroids and cytostatic drugs possess a documented lesive action on upper digestive mucosa, making epigastric pain and/or pyrosis common complaints among patients on antitumor treatment. The selective antimuscarinic pirenzepine and the H2-receptor antagonist ranitidine were tested against the ulcerogenic action of antiblastic chemotherapy. Thirty-eight patients affected with malignant lymphoproliferative disorders were endoscopically examined and the endoscopic pictures were quantified by using an arbitrary score. According to a double-blind randomized sequence, 19 out of the 38 patients received pirenzepine 100 mg/die/p.o. and the other 19 received ranitidine 300 mg/die/p.o. along with antitumoral therapy for periods of 3-6 months. Seven patients died of hematologic complications before ending the treatment. In the 31 surviving patients (13 pirenzepine- and 18 ranitidine-treated) a second endoscopic examination was performed at the end of the treatment and the lesion score repeated. No significant difference was found between initial and final scores in both groups. The antisecretive action of the two drugs may account for their effectiveness, but other mechanisms such as cytoprotection cannot be ruled out.

Adult↗
PubMed1985

Use of antisecretory drugs for gastroprotection during antiblastic chemotherapy.

Both prednisone and cytostatic drugs have an ulcerogenic effect on digestive mucosa. The protective action of the antisecretory drugs pirenzepine and ranitidine are compared against gastroduodenal lesions induced by antiblastic therapy. Twenty patients affected with lymphoproliferative disorders were endoscopically examined: none of them suffered from gastric or duodenal peptic ulcers or erosions. Ten out of the 20 patients received pirenzepine 100 mg/die/p.o. and the other 10 received ranitidine 300 mg/die/p.o. The study was performed according to a double-blind, randomized sequence. The antisecretory medication was administered together with antitumoral therapy for periods of 3-6 months. Four patients died of haematological complications before the course of treatment was completed. A further endoscopic examination was performed at the end of treatment: no patient showed evidence of gastric or duodenal peptic ulcers or erosions. Among the pirenzepine-treated cases, 1 out of the 7 evaluable patients showed a histological worsening of a pre-existing gastritis, while a slight duodenitis was observed in 1 out of the 9 ranitidine-treated patients. The comparable effectiveness of the two drugs is probably related to their antisecretory action, but cytoprotective mechanisms cannot be excluded.

Adult↗
PubMed1975

[Determination of urinary total proteins and some protein fractions].

In unconcentrated specimens measurements have been made of total proteins, by DOETSCH gel-filtration method, and of albumin, transferrin and of alpha-2-macroglobulin, by LAURELL electroimmunodiffusion technique. The results confirm that the gel-filtration method provides specific, reliable measurement of proteins in amount as little as 50 mg/1. The proteinuria of 21 samples of urine has been determined by the DOETSCH method and by the biuret method after protein precipitation by perchloric, trichloracetic and phosphotungstic acid. Only the use of phosphotungstic acid as precipitant provides a good correlation of results between the biuret method and the direct gel-filtration-biuret method. LAURELL electroimmunodiffusion technique was improved to allow the determination of 5 mg/1 of albumin, and transferrin, and of 1 mg/1 of alpha-2-macroglobulin. The AA. emphasize the advantages of using sensitive methods which do not require the preliminary concentration of the sample, for the analysis of urinary proteins.

Albuminuria↗