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Biomedical subjects

M Barbier

Publications and source records attributed to M Barbier.

At least 19 recordsLinked to original sources
PubMed1992

Study of pentoxifylline induced modulation of TNF alpha and interleukin-6 secretion in healthy and septic patients by the use of an ex-vivo model on whole blood.

The aim of this work is to reinvestigate the pentoxifylline (PTX) action on TNF alpha and IL-6 production using a whole blood ex-vivo model. 5 healthy controls, 2 septic patients (4 samples) and 3 patients in septic shock (7 samples) have been studied. Our data confirm the inhibitory action of PTX on TNF alpha production in healthy controls. This inhibition is nearly complete for a PTX concentration of 10(-3) M. More surprisingly a suppressive activity of PTX on IL-6 secretion has been found both in controls and septic patients. On the 7 samples of the 3 patients with septic shock no TNF alpha production has been detected. Taken altogether, these observations suggest a potential role for PTX as a modulator of the major cytokines involved in the pathogenesis of septic shock.

Blood↗
PubMed1992

Open trial of tacrine therapy in 70 HIV-infected patients.

The purpose of this study consisted in following-up the biological and clinical parameters in HIV infected patients treated with tacrine (THA). THA (150-300 mg/d) was administrated to 70 patients (39 IVC I and 31 IVC II and III). Thirty-five were treated after discontinuation of AZT treatment and 35 as a first intention treatment. Thirty (43%) patients showed an increase in the CD4+ cell count by more than 50% relative to pretreatment levels and fifteen (21%) showed an increase of more than 25%. p24 antigenemia (Ag p24) became negative in eight of the twenty-seven patients who were initially positive, and decreased by 25 and 50% in nine and six patients, respectively. Ag p24 was therefore decreased in 80% of the patients. From a clinical point of view, there were two deaths (3%) and five opportunistic infections (7%). The treatment with THA was stopped in five patients because of side effects (nausea, rash). Neither hepatotoxicity, hematotoxicity, nor pancreatitis was observed during the THA treatment. In group II and III only two patients (6%) developed an opportunistic infection.

AIDS-Related Opportunistic Infections↗
PubMed1990

Naphthoquinone pigments related to fusarubin from the fungus Fusarium solani (Mart.) Sacc.

A review is presented on the naphthoquinone pigments produced by the filamentous fungus Fusarium solani (Mart.) Sacc., and related species. After description of the naphthoquinone structures and biogenesis, the physiological and genetical controls of pigment production are discussed. The biological properties of the main naphthoquinone pigments so far investigated are described. Many problems still remain to be resolved in these fields, where Nectria haematococca (Berk. and Br.) Wr., the sexual state of Fusarium solani, is used as an experimental model.

Fusarium↗
PubMed1988

Interactions between ascorbic acid and linear and cyclized bile pigments. A thin-layer chromatographic study.

Physico-chemical interactions between ascorbic acid and the linear or cyclized bile pigment dimethyl esters were determined by thin-layer chromatography on silica gel. The interacting barrier technique allows a reactivity to be established that is a function of the degree of cyclization of the molecule. Thus, linear pigments of the biliverdin type are of low reactivity whereas the monocyclic neopterobilin phorcabilin shows a medium-strength interaction and isophorcabilin a strong interaction, the natural sarpedobilin being definitely captured by the ascorbic acid barrier on the silica gel layer. Spectrophotometric studies of the ascorbate-sarpedobilin interaction led to the conclusion that more than 2 mol of ascorbic acid are required per mole of pigment. The results are discussed in connection with the possible biochemical role of such bilins.

Ascorbic Acid↗
PubMed1988

IgE-dependent killing of Schistosoma mansoni schistosomula by human platelets: modulation by T cell products.

The in vitro stimulation of T lymphocytes is known to induce the release of factors that possess distinct biological activities. In the present report, we describe the presence, in supernatants of Schistosoma mansoni antigen stimulated T cells from S. mansoni infected patients, of a factor able to inhibit the IgE-dependent platelet cytotoxicity of the same individuals toward the young larvae of S. mansoni.

Animals↗
PubMed1987

Phomenoic acid and phomenolactone, antifungal substances from Phoma lingam (Tode) Desm.: kinetics of their biosynthesis, with an optimization of the isolation procedures.

Phomenoic acid and phomenolactone, previously isolated from the fungus Phoma lingam (Tode) Desm., have shown moderate antifungal and antibacterial properties in vitro. To rationalize the production of phomenoic acid, a kinetic study of its biosynthesis in the mycelium was performed. Phomenoic acid and phomenolactone appear in the mycelium after a prolonged incubation, a phenomenon which may be of particular interest for the production of these substances or in the study of the mechanism of their biosynthesis. The isolation procedure was optimized for phomenoic acid. Through a series of SiO2 column chromatographies, high-pressure liquid chromatography, and transformation of the mixture of phomenoic acid and phomenolactone into methyl phomenoate (BF3), the final yield of phomenoic acid reached 160 mg/liter of culture medium. An alternative method for the isolation of both phomenoic acid and phomenolactone is also reported in detail.

Antifungal Agents↗
PubMed1983

The action spectrum and phototransformations of pterobilin (biliverdin IX gamma).

Pterobilin 1 (biliverdin IX gamma), a butterfly bile pigment, is photocyclized into phorcabilin 2 and sarpedobilin 3 by irradiation in visible light. Selective irradiations have now been performed at the absorption maxima of pterobilin 1. The 650-nm radiations are responsible for the observed photocyclizations while the 375-nm radiations lead to decomposition products. These results are discussed in connection with a hypothesis concerning the biological role of pterobilin in butterfly larvae.

Animals↗
PubMed1982

Anthracyclic products from Streptomyces erythromogenes nov. sp. Biotransformation of daunomycin (Dn) by an acellular preparation and synergism between Dn and some known antibiotics.

The filtrate broth as well as mycelium of the new strain Streptomyces erythrochromogenes nov. sp. isolated from Saudi Arabian soil, produce the antitumor antibiotic daunomycin 1 and two anthracyclic derivatives: 7-deoxy 13-dihydrodaunomycinone 2 and 7-deoxy daunomycinone 4. The biotransformation of 1 to 2 and 4 by an acellular enzyme preparation from the strain was found to be NADPH and/or NADH dependent. Mixtures of daunomycin 1 with chloramphenicol or penicillin showed superior antimicrobial activities against Bacillus subtilis ICC strain, than the individual antibiotics.

Bacillus↗
PubMed1979

The diversity of marine sterols and the role of algal bio-masses; from facts to hypothesis.

Modern analytical methods have revealed the great variety of marine sterols, which possess many different side chains and unsaturation patterns. Such biochemical transformations require well-defined mechanistic pathways, and there must be some 'Raison d'Etre' for a situation which has withstood evolution and adaptive changes. However, in this area, insufficient and sometimes not very substantial experimental work has made it difficult to see correlations, and hence to form a solid hypothesis. A review is now presented in which the molecules dissolved in sea water, or found in marine organisms are considered with particular reference to algal production, and to the bio-ecological significance of the main sterols.

Animals↗
PubMed1979

[In vitro inhibition of tRNA methyltransferases by queen substance, a pheromone of queen honeybees].

The Queen Substance 1, a pheromone of the queen Honeybee Apis mellifica is an in vitro inhibitor of E. coli B tRNA methylations. This activity is not specific of the methylase source, as inhibitions have been observed with preparations from queen honeybee ovaries, Rat liver or a Mouse plasmocytoma 1-adenine methylase. These results, together with preceding ones concerning t, t-farnesyl-acetone 3, are discussed.

Animals↗