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Biomedical subjects

G B Gervasi

Publications and source records attributed to G B Gervasi.

13 recordsLinked to original sources
PubMed1991

A new low molecular weight heparan sulphate antagonizes kappa-carrageenan-induced thrombosis in rats.

Kappa-carrageenan (kappa-carrageenin; kappa-carragheen) was found to be thrombogenic in rats. After i.p. injection of 3 mg/kg of kappa-carrageenan the thrombosis extended to a maximum 7.5 cm from the tip of the tail. Infarction frequency as well as the extent of infarction were inhibited by oral administration of a new heparan sulphate of low molecular weight (LMW-HS) (alpha-idosane). Mesoglycan and heparin were active when administered by parenteral route, and aspirin showed no effect; mesoglycan was inactive at 50 mg/kg per os. The present data confirm the validity of this experimental model for evaluating the protective effects of antithrombotic drugs and show the activity of oral administration of a new drug endowed with fibrinolytic activity.

Animals↗
PubMed1991

Some chemical and biological properties of the low molecular weight heparan sulfate alpha-idosane.

A low molecular weight heparan sulfate derivative, alpha-idosane was separated from a mixture of glycosaminoglycans extracted from porcine mucosa. Its molecular weight, sulfur, uronic acid and hexosamine contents, C-NMR spectrum and electrophoretic properties are reported in this paper. The pharmacological effects of a-idosane were investigated "ex vivo" in dogs and rats. At doses of 10-50 mg/kg p.o., a-idosane shows fibrinolytic activity but it is devoid of anticoagulant action. At the dose of 100 mg/kg p.o. a-idosane exertes a significant anti-inflammatory effect but is unable to protect the rats against arachidonate-induced sudden death.

Animals↗
PubMed1991

Effects of a new aldose reductase inhibitor on diabetic complications in rats.

The effects of a new aldose reductase inhibitor, 7-fluoro-2-(N-methyl-N-carboxymethyl)sulfamoyl xanthone (BAL-ARI8, CAS 124066-40-6), on the diabetic complications of streptozotocin-induced diabetic rats were studied. The daily administration of BAL-ARI8 throughout the 8-week course of the experiment sharply decreased the sorbitol accumulation in the lens of the diabetic rats. The incidence of cataract formation was also reduced, being detected in only 45% of BAL-ARI8 treated animals, against the 100% of diabetic controls showing cataract after 8 weeks from diabetes onset. On the other hand, the serum glucose levels remained unchanged. In diabetic controls, there was about a 2.5-fold increase of the total protein urinary excretion during the 24 h. Treatment with BAL-ARI8 prevented up to 70% of this increase. Individual protein components were examined by polyacrylamide gel electrophoresis and quantitated by laser densitometric analysis. Diabetic-induced proteinuria primarily resulted from excretion of newly detected proteins with molecular weight in the range 30,000-60,000 D, together with an increase of albumin (25% of the total excretion) and the presence of new higher molecular weight proteins (greater than 66,000 D). BAL-ARI8 administration resulted in a shift of the protein profile back toward normality i.e. 73% of proteins with molecular weight below 30,000 D, 7.5% albumin and no proteins above 66,000 D. These results suggest that BAL-ARI8 may represent a therapeutic approach for the management of diabetic complications.

Aldehyde Reductase↗
PubMed1990

"In vitro" fibrinolytic activity of a new low molecular weight heparan sulfate.

The fibrinolytic activity, effect on the fibrinolytic activity of plasmin, anticoagulant activity and anti platelet aggregation activity of a low molecular weight heparan sulfate (LMW HS Bal) were investigated "in vitro" on blood plasma obtained from rats and rabbits. LMW HS Bal at concentrations as low as 0.25-2 micrograms/ml prevented thrombin-induced platelet aggregation. At concentrations 25 to 50 times larger it showed no significant anticoagulant activity but a marked fibrinolytic effect. At still larger concentrations LMW HS Bal also potentiated the fibrinolytic activity of plasmin. Conversely, unfractionated heparan sulfate (UHS) at concentrations of 25 to 50 micrograms/ml, only showed anticoagulant activity with no fibrinolytic activity.

Animals↗
PubMed1989

Decrease of diffusion of glycosylated albumin in retinal microcirculation by peptide fraction from bovine factor VIII.

The diffusion of the glycosylated albumin in the retinal vascular system has been studied in male New Zealand rabbits, using fluorangiographic techniques. A first group of animals was treated for 15 days with the peptide fraction from bovine Factor VIII (Vueffe); a second group, used as control group, was treated with physiological solution. At the end of treatment, glycosylated albumin was made fluorescent and then injected into the marginal vein of the rabbit. The direct observation and the photometric measurements performed on the digitized photograms with an image processing system showed a considerable reduction in retinic capillary diffusion of glycosylated albumin in the animals treated with the peptide fraction. The substance used in the study might therefore be of importance in the treatment of systemic disease with retinic vascular damage.

Angiography↗
PubMed1988

Polypeptide fraction from bovine factor VIII does not influence human platelet aggregation and blood coagulation.

It is well known that high molecular weight bovine factor VIII is able to aggregate human platelets and possesses procoagulant activities. There is also growing body of evidence that the hydrolysis of bovine factor VIII abolishes its aggregating and coagulative properties. We have shown in this paper that a polypeptide fraction (molecular weight 1000-25000 daltons) from bovine factor VIII does not aggregate platelets nor affect blood coagulation. In this study we investigate the action of the polypeptide fraction derived from bovine factor VIII and suggest that its effect may occur only at endothelium level without an involvement of platelets as well as blood coagulation.

Animals↗
PubMed1988

Polypeptide fraction from bovine factor VIII used in fluorangiography.

We report a new method of fluorangiography employing a polypeptide fraction from bovine factor VIII that has shown remarkable affinity to the endothelial surface of microvessels. Rabbits injected with this compound, labeled with fluorescein isothiocyanate, show a very delayed disappearance time of fluorescence in retinal vessels when compared with those injected with ordinary fluorescein. This allows a good observation of the late time, which is of great diagnostic advantage for several pathological conditions.

Animals↗
PubMed1988

Decrease of bleeding time by a peptide fraction from bovine factor VIII in laboratory animals.

A peptide fraction of low molecular weight prepared from bovine Factor VIII by enzymatic hydrolysis (Vueffe) reduces bleeding time in laboratory animals. In this study the haemostatic action in mice, rats and rabbits was investigated using different experimental conditions. This action was observed in animals with either normal or experimentally prolonged bleeding time, thus suggesting better efficacy in pathological situations. The evidence obtained following different routes of administration confirmed the activity of the compound. The efficacy was present at very low doses in all animal species without interfering either with platelets or with blood coagulation.

Animals↗
PubMed1977

Specific metabolic pathway in vitro of pinazepam and diazepam by liver microsomal enzymes of different animal species.

The metabolic pathway of Pinazepam and Diazepam in vitro was studied with rat, guinea pig and dog liver microsomes using a chromatographic and spectrophotometric technique. Two main pathways were observed, N1-dealkylation and C3-hydroxylation. N1-dealkylation was shown to be the predominant reaction for Pinazepam in all the animal species studied, while C3-hydroxylation was the major metabolic pathway for Diazepam in the rat. No oxazepam was found when Pinazepam and Diazepam were incubated with liver microsomes.

Animals↗
PubMed1977

Pharmacological properties of the anti-inflammatory agent pyridyl-biphenylyl-acetamide (diphenpyramide).

Pyridyl-biphenylyl-acetamide (diphenpyramide, Z-876) is a new bisphenylalcanoic derivative with marked anti-inflammatory, analgesic, antipyretic and uricosuric properties. It is more active than phenylbutazone in the adjuvant polyarthritis in the rat when given prophylactically or therapeutically. It is thrice as active as phenylbutazone and ten times as active as acetylsalicylic acid (ASA) on the carrageenin-induced edema of the hind-paw. Diphenpyramide is characterized by low acute toxicity and by weak ulcerogenic activity. On the carrageenin-induced edema the therapeutic index of diphenpyramide is 30 times higher than that of indometacin and the ratio between the ED50 and the UD50 (ulcerogenic dose in 50% of the treated rats) is 39 times higher than that of ASA.

Acetamides↗
PubMed1976

Serum kinetics and urinary metabolism of dimethophrine in rat.

The serum kinetics and urinary metabolism of an a-sympathomimetic amine 1-(3,5-dimethoxy-4-hydroxyphenyl)-2-monomethyl-amino-ethanol (dimethophrine) were studied. For serum kinetics, seven groups of 6 rats were sacrificed at 0.083, 1, 2, 2, 4, 6 and 12 H, respectively, after tail administration of dimethophrine-7-3H. Only 1 group of 6 rats was placed into metabolism cages to collect urine at 12-h intervals during the 72 h after dimethophrine-7-3H administration as above. The metabolic identification was made by thin-layer chromatography (TLC) and the radiochromatograms were obtained by the "scraping" method. This work shows dimethophrine to be unchanged in the urine of rat.

Animals↗
PubMed1975

Determination of pinazepam and its metabolites in serum, urine and brain by gas-liquid chromatography and mass spectrometry.

A sensitive and specific assay, involving electron capture gas-liquid chromatography, has been developed for the identification of pinazepam and its metabolites in serum, urine and brain samples from dogs and rats after single or repeated oral administration of the drug. Serum and urine samples from healthy humans after a single oral administration have also been analysed. The identity of gas-liquid chromatographic peaks has been established by mass spectrometry. In blood serum and brain, only pinazepam and its N-depropargylated product (demethyldiazepam) were found; from urine, 3-hydroxypinazepam and oxazepam were also recovered. The sensitivity of the gas-liquid chromatographic method is of the order of 5-10 ng of pinazepam and 15-20 ng of the other three benzodiazepines per ml of serum.

Administration, Oral↗