PubMed Health⌕ Search

Biomedical subjects

G Andriuoli

Publications and source records attributed to G Andriuoli.

13 recordsLinked to original sources
PubMed1997

Fluoroaluminate induces rapid release of endothelin-1 in the isolated perfused arterial and venous vessels of the rat mesentery.

1. Endothelin-1 (ET-1) production from endothelial cells is generally believed to be a process that happens over the course of hours. 2. When fluoroaluminate (AIF-4) was infused in the isolated perfused arterial and venous vessels of the rat mesentery there was an increase in perfusion pressure on both sides. 3. Treatment of mesentery with the endothelin receptor antagonists FR 139317 (ETA receptor selective) or PD 145065 (ETA-ETB receptor nonselective) caused inhibition on both the arterial and venous sides, suggesting that response is mediated predominantly by endothelin-1 through ETA receptors. 4. Endothelial denudation attenuated changes in perfusion pressure of mesenteric circulation generated by fluoroaluminate, but not those caused by exogenously added PGF2 alpha. 5. Our data demonstrate that there is an immediate release of endothelin-1 following fluoroaluminate infusion which could be partially mediated by activation of phospholipase C.

Aluminum↗
PubMed1996

Increase in the basal tone of guinea pig thoracic aorta induced by ouabain is inhibited by spironolactone canrenone and potassium canrenoate.

Guinea pig aorta rings repeatedly stimulated with phenylephrine (1 microM) in the presence of Krebs solution containing ouabain (0.8 microM) or low K+ (0.5 mM) concentration produced an increase in basal tone. This effect is due to an increase in intracellular Ca2+ as a consequence of Na(+)-K+ATPase pump inhibition induced by receptorial (ouabain) or ion imbalance (low K+) mechanism. We investigated the effect of spironolactone and its metabolites canrenone and potassium canrenoate on the increase in basal tone of guinea pig aorta rings. Spironolactone, canrenone, and potassium canrenoate, in a concentration-dependent manner (3-30 microM), inhibited the increase in basal tone induced by ouabain, most likely acting as antagonist for ouabain binding site on Na(+)-K+ATPase pump. Indeed, this effect appears to be a feature of these drugs since structurally related drugs, such as aldosterone and hydrocortisone, were ineffective. Conversely, all the drugs tested reduced, to a certain degree, the increase in basal tone produced by low K+ Krebs solution, implying that this could be a non-specific effect. Our results may indicate that spironolactone, canrenone, and potassium canrenoate act in hypertension by interfering with mechanisms in which an ouabain-like factor is involved.

Animals↗
PubMed1992

Intraduodenal absorption in the rabbit of a novel heparin salt.

The intraduodenal absorption of a new low-molecular-weight heparin (LMWH) diamine salt (ITF 1331) was compared with the parent compound ITF 1060 and with sodium LMWH, in anaesthetized rabbits. The administration of either salt, but not of sodium LMWH, resulted in a dose-related increase in plasma anti-Xa activity. In this respect ITF 1331 was slightly superior to ITF 1060, and in acute-toxicity studies the counterion itself (ITF 258) was less toxic than that in ITF 1060 (counterion No. 4). These data confirm that a tertiary diamine within the counterion is an important structural requirement for the bioavailability of heparin by the intraduodenal route, and suggest that ITF 1331 may represent an important advance in the search for an oral heparin.

Animals↗
PubMed1991

Heparin prevents stasis-induced thrombosis through protection of the venous endothelial cells: an electron microscopic study in rabbits.

This study was performed to see whether or not protection of the endothelial cells contributes to the antithrombotic effects of heparin. New Zealand albino rabbits were subjected to jugular vein stasis by single caudal ligation for 2 h. Three treatments were given: saline (control group), heparin (0.2 mg/kg) 5 or 45 min before ligature of the vein. Groups of 6-8 animals were killed at 0, 5, 15, 30 and 120 min. The following parameters were determined: (1) involution and damage of the endothelial cells by scanning and transmission electron microscopy; (2) incidence and weight of thrombi in the lumens of the veins after 2 h stasis, and (3) effects of heparin on APTT and anti-Xa activity. In the control group, stasis caused a considerable involution of the endothelial cells in the first 30 min, followed by fibrin deposition and thrombus generation. Heparin strongly reduced the damage to the endothelial cells, with very evident protection of the cell membranes, and prevented thrombus generation: there were significant decreases in both incidence and weight of thrombi. These effects of heparin were evident both shortly after (maximal anticoagulant effect) and long after (no anticoagulant effect) pretreatment. We think that, under the experimental conditions we used, heparin prevented venous thrombosis at least partially by protection of the endothelial cells, through unknown mechanisms.

Animals↗
PubMed1991

Diuretic agents related to indapamide. IV--Synthesis and pharmacological activity of N-(4-chloro-3-sulfamoylbenzamido)-methyl-phenyl-pyrrolidines and N1-(4-chloro-3-sulfamoylbenzoyl)-N2-aryl- or aralkyl-alkyl-hydrazines.

A series of N(4-chloro-3-sulfamoylbenzamido) derivatives (6 a-c, 10, 11, 12), structurally related to indapamide and isoindapamide, were synthesized and tested for their diuretic and saluretic activity. In addition, the antihypertensive activity of the most interesting term trans 6a was studied on spontaneously hypertensive rats. All tested compounds with the exception of 10 showed diuretic activity comparable to or higher (trans 6 a) than that of indapamide, taken as reference drug. The antihypertensive activity of trans 6 a was comparable to that of indapamide in potency, but its onset of action was slower.

Animals↗
PubMed1990

Heparin by alternative routes of administration.

In a study investigating the bioavailability of heparin administered by different routes, we also compared its bioavailability in the dog after oral administration of two enteric-coated formulations, one containing a heparin preparation (ITF-300) and the other sodium heparin. After administration of the formulation containing sodium heparin, there was no heparin in plasma, but when the formulation containing ITF-300 was given, plasma heparin levels were detectable.

Administration, Oral↗
PubMed1990

Comparison of anti-anaemic effects of iron protein succinylate (ITF 282) and ferrous sulfate in the rat.

The effects of iron protein succinylate (ITF 282), an iron complex insoluble under acid conditions, and ferrous sulfate were studied in the rat. After a single oral administration of ITF 282, the concentration of free iron in the stomach was less than the 10% of that found after a corresponding dose of ferrous sulfate and the effect of induction of diarrhoea was significantly less important than that of ferrous sulfate. Iron absorption and kinetics were evaluated by measuring serum iron after oral administration of equidoses of iron to the anaemic rat. The results showed that ferrous sulfate induces higher serum iron levels than ITF 282. The anti-anaemic effects of the two iron products were studied during 4 weeks of treatment (3 mg iron/kg/day): the data obtained confirmed that ferrous sulfate is significantly more potent in increasing serum iron, but in contrast both compounds are equally active in restoring normal haemoglobin values.

Anemia, Hypochromic↗
PubMed1986

Antithrombotic effect of OP/LMWH by subcutaneous route in rats.

The aim of this study was to compare the antithrombotic and haemorrhagic effects of unfractionated heparin and OP/LMWH, a new low molecular weight heparin fragment, after subcutaneous administration in rats. Both heparins showed antithrombotic efficacy in a model of acute venous thrombosis even at 1 mg/kg; furthermore OP/LMWH presented a significantly higher activity in subacute venous thrombosis of the rat. At all the dosages tested OP/LMWH showed a significantly shorter bleeding time in the rat by the "transection" method, compared with unfractionated heparin. This study suggests the possibility of dissociating the antithrombotic and haemorrhagic effects of some heparin fractions.

Animals↗
PubMed1985

Comparison of the antithrombotic and haemorrhagic effects of heparin and a new low molecular weight heparin in rats.

A new low molecular weight heparin (LMWH) and a conventional unfractionated heparin (H) were tested in rats for venous antithrombotic activity and bleeding tendency after intravenous administration. Both drugs showed antithrombotic activity, but LMWH at the low dosages tested (0.1 and 0.25 mg/kg) demonstrated significantly higher activity than H. In a rat bleeding time test (transection model) both heparins produced a prolonged bleeding time, but LMWH possessed significantly less potency than H at all the dosages tested. Ex vivo coagulation parameters (activated partial thromboplastin time and antiXa activity) were also evaluated: LMWH presented very low activity on the APTT test and a sustained antiXa activity, comparable to that of H.

Animals↗
PubMed1984

Antithrombotic activity of a glycosaminoglycan (sulodexide) in rats.

Glycosaminoglycans extracted from various sources are extensively utilized in the treatment of occlusive vascular disease. These products have shown to possess antithrombotic activity in some experimental thrombosis (1,2). Our purpose was to study the activity of Sulodexide, an heparin-like compound (3,4), on rat model of arterial thrombosis and to study its interaction with platelets.

3,4-Methylenedioxyamphetamine↗
PubMed1982

Synthesis and pharmacological evaluation of new compounds with a potential action on the adrenergic system.

A series of compounds with a potential activity on both alpha and beta-adrenoreceptors were synthesized and evaluated with in vitro and in vivo tests. Aryloxypropanolamino derivatives N-substituted with alpha 2-benzodioxanylmethyl group showed a favourable alpha/beta ratio and a high selectivity towards beta 1 receptors. Substitution with different aralkyl groups afforded compounds with a low alpha-activity, although with a high potency and selectivity towards beta 1 receptors. The results are discussed on the basis of the working hypothesis and compared with those obtained for reference compounds.

Adrenergic alpha-Antagonists↗