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Biomedical subjects

A Gasco

Publications and source records attributed to A Gasco.

14 recordsLinked to original sources
PubMed1992

4-Methyl-3-(arylsulfonyl)furoxans: a new class of potent inhibitors of platelet aggregation.

A series of 4-methyl-3-(arylthio)furoxans were synthesized by oxidation of 1-(arylthio)-2-methylglyoxymes with dinitrogen tetroxide. Reduction with trimethyl phosphite of the furoxan derivatives afforded the corresponding furazans, while oxidation with an equimolar amount of 30% hydrogen peroxide in acetic acid or with an excess of 81% hydrogen peroxide in trifluoroacetic acid afforded the corresponding arylsulfinyl and arylsulfonyl analogues, respectively. All the furoxan and furazan derivatives showed activity as inhibitors of platelet aggregation. 4-Methyl-3-(arylsulfonyl)furoxans were the most potent derivatives of the series. 4-Methyl-3-(phenylsulfonyl)furoxan (10a), one of the most active derivatives, inhibits the AA-induced increase of cytosolic free Ca2+ and production of malondialdehyde. A primary action of the compound on cyclooxygenase is excluded, as a stable epoxymethano analogue of prostaglandin H2 does not reverse the inhibitory effect of 10a. This compound produces a significant increase in cGMP which is likely to cause inhibition at an early stage of the platelet activation pathway.

Arachidonic Acid↗
PubMed1992

Characterization of a new compound, S35b, as a guanylate cyclase activator in human platelets.

The effects of S35b (4-methyl-3-phenyl sulfonylfuroxan), a new phenyl sulfonylfuroxan compound, were investigated on human platelets activated by different agonists. Platelet aggregation evoked by arachidonic acid (AA), collagen, ADP and thrombin was inhibited by the drug in a dose-dependent manner. S35b inhibited the AA-induced increase of cytosolic free Ca2+ ([Ca2+]i) and production of malondialdehyde. A primary action of the compound on cyclooxygenase is unlikely since: (1) U-46619 (15s-hydroxy-11,9-[epoxymethano]-prosta-5Z,13E-dienoic acid, a stable epoxymethano analog of prostaglandin H2) could not reverse the inhibitory effect of S35b on AA-induced aggregation and [Ca2+]i increase; (2) U-46619-induced aggregation and [Ca2+]i rise were inhibited by S35b; and (3) at high collagen concentrations platelet aggregation (which is unresponsive to aspirin under such conditions) was blocked by S35b as well. Thus the drug action is likely to be exerted at an early step of the platelet activation pathway. The elevation in the platelet cGMP level evoked by S35b in a time- and concentration-dependent manner can account for the inhibitory effect: increased cGMP levels could interfere, for instance, with G protein-phospholipase C coupling and subsequent phosphoinositide hydrolysis.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1992

Potential histamine H2-receptor antagonists: synthesis and pharmacological activity of derivatives containing acylamino-furazan moieties.

Analogues of 3-amino-4-[2-[(5-dimethylaminomethyl-2-furyl)methylthio]ethylamino] furazan (1) containing carbonyl groups joined to the amino functions linked to the furazan system have been synthetized and investigated for their H2-antagonist properties on the isolated guinea pig right atrium. The presence of the carbonyl group lowers the activity in respect to the corresponding leads. The decrease in activity is only by 1-2 orders of magnitude in the 3-acylamino-furazan series versus inactivity in the 4-acylamino isomers and in the diacylated series.

Animals↗
PubMed1992

Furan and thiophene analogues of omeprazole.

Synthesis and structure of some analogs of the omeprazole containing furan and thiophene rings are reported. Their effects on the basal and the histamine-stimulated secretion were evaluated on the isolated rat stomach.

Animals↗
PubMed1992

Synthesis and H2-antagonist properties of some 1,2,5-thiadiazole-1-oxide derivatives.

A series of 1,2,5-thiadiazole-1-oxide derivatives has been synthesized and studied for its H2-antagonist properties. These derivatives can be considered derived from classical H2-antagonists in which the structure was deeply modified in order to evidence the minimal structural requirements for the activity. It was found that it is sufficient to have the 1,2,5-thiadiazole-1-oxide ring substituted with an alkylamino moiety and with an aliphatic chain linked to the hydroxy or ether group to achieve compounds as active as cimetidine. A few considerations on the binding on guinea-pig cerebral cortex of a series of H2-antagonists with more and more simplified structures are also reported.

Animals↗
PubMed1989

Potential histamine H2-receptor antagonists. Synthesis, structure and activity of a few open models related to classical H2-antagonists.

A few ethers and oximes structurally related to classical H2-antagonists have been synthetized and tested for their in vitro H2-antagonist activity. The compounds in which cyclic "urea equivalent" groups are joined to a cyclohexylmethyl moiety showed a high increase of activity in comparison with the unsubstituted analogues. This finding supports the hypothesis of the existence of an accessorial binding area on H2-receptor near the site fitted by cyclic "urea equivalent" groups.

Animals↗
PubMed1988

In vitro cytotoxic activity of aryl and heteroaryl-ONN-azoxycyanides.

Some aryl-N(O) = N-X and heteroaryl-N(O) = N-CN compounds were synthetized and tested against a culture of HeLa cells. The results obtained show that the - N(O) = N beta CN function, a new cytostatic group, is useful in the design of potential antitumoral compounds.

Antineoplastic Agents↗
PubMedDate not supplied

[Time in depression].

Subjective estimation of time varies according to age, to physical state and to the activity we are occupied with. The relationship between time and major depression can be considered from two different point of view. From a clinical-psychological point of view normal subjects with major depression estimate time intervals differently. Future, past and present change their meaning in major depression. These alterations cause important consequences in the cognitive structure of subjects with major depression and therefore influence depressive symptoms. On the other hand also the "biological time" is altered in major depression. Subjects with major depression suffer from many chronobiological alterations. The relationship between these two aspects are considered in the present report.

Circadian Rhythm↗