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Biomedical subjects

M Plat

Publications and source records attributed to M Plat.

At least 37 records · Page 2Linked to original sources

[Active principles of plant origin: a tool for studying membrane receptors].

Ever since ancient times, considerable interest has been shown in plants for therapeutic use. Nowadays, however, studies of plant extracts are no longer based on empiricism; they provide great support to fundamental research, especially for a better understanding of the mediator/receptor couples. This applies to the study of cholinergic (atropine, muscarine, etc.), adrenergic (yohimbine, rauwolscine, etc.), dopaminergic (apomorphine, bromocriptine, etc.), purinergic (caffeine, theophylline, etc.), opiate (morphine), GABA (strychnine, muscimol, bicuculline, etc.), cardiac glycosides (gitaloxin, digitoxin) and PAF-acether receptors (ginkgolides from Ginkgo biloba).

Cell Membrane↗

A new potent inhibitor of lipid peroxidation in vitro and in vivo, the hepatoprotective drug anisyldithiolthione.

The drug anisyldithiolthione (ADT) acted as a good inhibitor of lipid peroxidation induced in rat liver microsomes either chemically by FeSO4 and reducing agents (cysteine or ascorbate) or enzymatically by NADPH and CC14. ADT was found as potent as propylgallate with IC50 around 2 microM and much more potent than vitamin E and levamisole. ADT was also found as a good inhibitor of ethane exhalation by rats treated by CCI4 (ID50 approximately 5mg per kg) and by mice intoxicated by acetaminophen (ID50 approximately 0.7 mg per kg). At doses as low as 5 mg per kg it completely suppressed ethane exhalation by acetaminophen-intoxicated mice and also protected them very efficiently against mortality caused by acetaminophen overdose. The inhibitory effect of ADT toward lipid peroxidation seems to be linked to the presence of its dithiolthione function.

Acetaminophen↗

Bacterial conjugation in the digestive tracts of gnotoxenic chickens.

Escherichia coli K-12 Hfr and F- strains were successively implanted in axenic chicks. Conjugation with exchanges of chromosomal genes occurred with high frequencies in the gut of the chicks and could continue as long as fertile strains coexisted in this environment. Almost all of the expected recombinant types were recovered in the feces under these experimental conditions. Furthermore, these recombinants were analogous to those obtained after conjugations in vitro. Recombinants formed in the gut were more numerous when the F- strain was seeded before the Hfr strain. The recombinants showed no apparent selective advantage over the parental strains in the intestinal medium. They were maintained throughout the experimental period and represented more than 10% of the total intestinal flora. The chick gut is usually rapidly colonized by other bacterial types under natural conditions. The possible effects of other components of the bacterial flora on conjugation of E. coli in holoxenic animals will require subsequent work with more complex microbiological conditions.

Animals↗

Pharmacokinetic study of two pharmaceutical preparations containing alkaloid vincamine administered orally to human subjects.

In a crossover study of six healthy volunteers the pharmacokinetics and the bioavailability of vincamine were studied after administration of two oral forms. All subjects received an oral dose of 60 mg vincamine. The plasma concentrations of the drug were determined by a specific and sensitive gas chromatographic method. In this kind of subject the drug generally follows a one-compartment kinetic model. The average value of Tmax is 1.4 +/- 0.5 h-1 with the tablets and 1 +/- 0.6 h-1 with the solution; the Cmax are, respectively, 155 +/- 82 micrograms . 1(-1) and 133 +/- 104 micrograms . 1(-1). The AUC are 443 +/- 156 micrograms . 1(-1) h with the tablets and 315 +/- 178 micrograms . 1(-1) h with the solution. The short elimination phases, 1.43 +/- 0.80 h with the tablets and 1.55 +/- 0.78 h with the solution should be taken into account during chronic administration.

Administration, Oral↗

[In vitro metabolism of 4-benzylisoquinolines, analogs of papaverine].

A comparative study was made on sliced Rat liver of the in vitro disappearance of papaverine, PV 2 6,7-dimethoxy-4-(parachlorobenzyl)isoquinoline and its mono and di isopropoxy derivatives. Data show that papaverine and PV 2 are equally sensitive to oxygenases, although 7 mono and 6,7 di-isopropoxy derivatives are much less so, being more bulky and undergo in enzymic O-dealkylation less easily. The data also show that PV 2 and 6-isopropoxy desmethoxy PV 2 disappear at the same rate, more readily than the 7 isopropoxy isomer. This confirms the in vivo results previously reported. The antispasmodic in vitro activity of these compounds is reported.

Animals↗

[Syntheses designed to produce 8-amino ellipticine. Synthesis and pharmacological properties of 8-nitro ellipticine].

The synthesis of 8-nitro ellipticine starting from 6-nitro indole is reported. It is the first derivative of ellipticine substituted in position 8 obtained by total synthesis. In contrast to 9-nitro ellipticine the 8-nitro derivative could until now not be reduced to 8-amino ellipticine. To obtain the latter it was intended to arylate an enamine of the 2,5,8-trimethyloctahydroisoquinolone-6 by 1-chloro 2,4-dinitrobenzene, followed by a reductive cyclization and N-demethylating aromatization. Since the yield of the arylation step was low, the isoquinolone was replaced by 2,5-dimethyl cyclohexanone and the synthesis would have to be completed by addition of a pyridine ring. In the case the yield of the aromatisation was 37%, but the carbazole derivative resisted all formylation attempts. 8-Nitro ellipticine was investigated for its DNA affinity, its cytotoxic activity on L 1210 tumors cells and its toxicity in the mouse. The results obtained were compared with those for 9-nitro ellipticine and in regard to cytotoxicity, with those for the 8- and 9-hydroxy ellipticines.

Alkaloids↗

[Not Available].

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France↗