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Biomedical subjects

R Pescador

Publications and source records attributed to R Pescador.

52 records · Page 3Linked to original sources
PubMed1986

Gastroprotection and lysosomal membrane stabilization by sulglicotide.

Well-known agents that induce gastric ulcers cause a decrease in lysosomal stability, with release of lytic enzymes. Some antiulcer and cytoprotective agents have lysosomal membrane stabilizing activity when tested in vitro and ex vivo. Sulglicotide (Gliptide), a polysulfated glycopeptide with antiulcer and cytoprotective activities, was able to stabilize lysosomal membranes in vitro at concentrations between 9 and 36 micrograms/ml. The ratio of potency of sulglicotide to that of carbenoxolone was 12.2. In ex vivo experiments in rats, it was found that sulglicotide stabilized lysosomes after oral treatment. The effect was dose-dependent after intravenous treatment. Carbenoxolone, injected i.v. under the same experimental conditions, was less active (potency ratio 0.65). 16,16-dimethyl-PGE2, administered at a dose of 10 micrograms/kg orally or intravenously, had an activity equivalent to that of sulglicotide at a dose of 12.5 mg/kg i.v. or 200 mg/kg p.o. Sulglicotide (200-400 mg/kg p.o.) was also able to prevent the release of acid phosphatase from stomachs challenged for 10 min or 3 h with absolute ethanol. The same result was obtained with 200 mg/kg p.o. of carbenoxolone. These data show that sulglicotide is a potent lysosomal membrane stabilizer in vitro and ex vivo, and could explain the cytoprotective activity of this compound in different experimental models of ulcer.

Animals↗
PubMed1985

Cardioprotective effects of defibrotide in acute myocardial ischemia in the cat.

We investigated the effects of Defibrotide (D), a natural polydeoxyribonucleotide, on acute myocardial ischemia (AMI) in anesthetized cats. A permanent ligature was placed around the left anterior descending coronary artery (LAD) 12-14 mm from its origin. Ventricular fibrillation and death were exceptional and when they occurred the cats were not included in the evaluation. Pretreatment of cats with D, 32 mg Kg-1 h-1, i.v. infusion, maintained throughout the 5 h occlusion period, reduced AMI-ST segment increases and increased the diminished pressure-rate index (PRI). AMI-induced changes in lactate, ATP and CPK in ischemic tissue were prevented by D. PGI2 gave the same results as D. Atenolol prevented the loss of myocardial CPK, but had no favourable effects on lactate and ATP in ischemic tissue. The beneficial effects of D in AMI reported here could be partly attributed to its ability to enhance PGI2 release from vascular walls; D might also relieve ischemia by improvement of local tissue oxygenation, energy supplies and platelet function by its ability to deaggregate platelet clumps.

Acute Disease↗
PubMed1983

Pharmacokinetics of Defibrotide and of its profibrinolytic activity in the rabbit.

An extensive study of the pharmacokinetics and the pharmacokinetics of the profibrinolytic activity of Defibrotide (D) in the rabbit has been made. a two compartment model was used to describe D's pharmacokinetics. The parameters of drug disposition and the rate constant of release from tissues to central compartment were closely dose-dependent. The dose-response curves for elimination parameters were powers with a negative exponent indicating considerable saturation of this process. As a consequence, the T1/2, Co and AUC were also dose-dependent, as were the parameters describing the decrease in profibrinolytic activity in the blood stream.

Animals↗
PubMed1983

Plasma lipoproteins, postheparin plasma lipoprotein lipase activity intralipid half-life, triglyceride secretion rate and liver lipids in the mouse fed different cholesterol diets.

Mice (SC), fed a semipurified diet containing cholesterol, cholic acid and sucrose, exhibited, in comparison to control animals (S), an increase in cholesterol, phospholipid and protein of VLDL, LDL1 and LDL2, but triglyceride of the same lipoproteins decreased, as did total plasma triglycerides. Postheparin plasma lipoprotein lipase activity of SC animals was 1.72 times that of S mice. At the same time Intralipid half-life in SC mice was decreased by 52%. Triglyceride secretion rate, after Triton WR 1339 treatment, and liver triglyceride content were reduced in SC animals. HDL mass was decreased in SC mice. Mice (AC) fed a standard diet containing cholesterol showed, in comparison to normal fed animals (A), an increase in cholesterol of VLDL, LDL1 and LDL2 but triglyceride of the same lipoproteins decreased as did total plasma triglycerides. Postheparin plasma lipoprotein lipase activity of AC animals was unmodified as was Intralipid half-life. In AC animals triglyceride secretion rate, after Triton WR 1339 treatment, was reduced but in a less extent than in SC mice. Liver triglyceride was unmodified. HDL mass was decreased in AC mice.

Animals↗
PubMed1983

Correlation between structure, fat-clearing and anticoagulant properties of heparins and heparan sulphates.

Heparins and heparan sulphates from different organs, of high purity by accepted criteria, were characterized by chemical and physical (including electrophoretic and 13C-NMR spectroscopic) methods. The fat-clearing activity of these preparations was shown to be correlated with their content of the trisulphated disaccharide units I2S-ANS,6S (L-iduronic acid 2-O-sulphate-N-sulphated D-glucosamino 6-O sulphate). Species with low anti-lipemic activity contained significant proportions (greater than or equal to 30%) of nonsulphated uronic acids (especially D-glucuronic acid), and of D-glucosamino residues undersulphated at C-6, these latter residues being partially N-acetylated. Heparins from beef lung and sheep mucosa, predominantly consisting of trisulphated disaccharide units, displayed consistently higher antilipemic activity than the more heterogeneous pig mucosal heparins. The anticoagulant activity (as determined by the U.S.P., APTT and anti-Xa tests) was not a simple function of the measured physicochemical parameters. Trends were confirmed for pig mucosal heparins being more anticoagulant than beef lung preparations, and low molecular weight (usually undersulphated) species being more active in the anti-Xa test than in the U.S.P. and APTT tests.

Amino Acids↗
PubMed1983

Pharmacokinetics of catalytically tritiated glycosaminoglycans in the rat.

Glycosaminoglycan mixture catalytically labelled with tritium gas (3H-GAG) was shown to have chemical characteristics and antithrombin-heparin cofactor activity in vitro similar to those of the native mixture of glycosaminoglycans (GAG). Rats were orally dosed with 3H-GAG in either aqueous solution or vegetable oil emulsion and the quantity of radioisotope absorbed assessed at various intervals. The quantity of 3H in plasma plateaued 8 h after dosing and remained near peak levels at least 16 h. Time dependent accumulation of the radioisotope within liver, spleen and testes was also observed.

Animals↗
PubMed1982

Pharmacokinetics of fluorescein-labelled glycosaminoglycans and of their lipoprotein lipase-inducing activity in the rat.

Using fluorescein-labelled glycosaminoglycans (F-GAG) an extensive study of their pharmacokinetics and of pharmacokinetics of their lipoprotein lipase-inducing activity was carried out in fed and fasted rats. A two-compartment model was used to describe F-GAG's pharmacokinetics. The parameters of drug disposition were strongly dose-dependent. The dose-response curves for parameters were powers with negative exponent indicating considerable saturation of the F-GAG elimination process. There was also dose dependence for T1/2, Co, AUC and Cl, and the decrease in lipoprotein lipase activity in plasma was strongly dose-dependent. The lipoprotein lipase kinetic parameters also appeared to be dose-dependent.

Animals↗