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Biomedical subjects

P Fournier

Publications and source records attributed to P Fournier.

206 records · Page 12Linked to original sources
PubMedDate not supplied

[Biotransformation of dimethylnitrosamine].

NDMA, one of the most widely occurring carcinogenic compounds in the environment, is present in human food (meat, vegetables, cheese and alcohol beverages), in drinking water, in drugs, in cosmetics, in tobacco and its smokes. Furthermore NDMA may be synthesized from nitrates and nitrites and endogen or exogen amines. Since the first observations of MAGEE and BARNES in 1956 on the carcinogenicity of NDMA, this compound was reported to be carcinogenic in a large number of animal species including mammals, birds, amphibia and fish. NDMA requires metabolic activation for its cytotoxic and carcinogenic actions. The major activation step is believed to be the oxygenation of the alpha-carbon catalysed by a Cytochrome P-450-dependent enzyme system commonly know as NDMA-demethylase. Studies on the enzymology of NDMA metabolism show that some Cytochrome P-450 isozymes exhibit significant NDMA-demethylase activity only at high NDMA concentrations. The form of P-450 inducible by factors such as, fasting, diabetes, ethanol consumption and pretreatment with acetone, pyrazole or isopropanol has the higher affinity for NDMA. The gene coding for this isozyme belongs tho the P-450 II E subfamily. Because NDMA-demethylase activity is decreased by monoamine oxidase inhibitors, some authors have suggested a possible role of MAO in NDMA demethylation. This view is not supported by others who don't find evidence for an involvement of MAO in NDMA metabolism. Likewise, there are contradictory reports about the existence of some NDMA demethylase activity in cytosol, nuclei and mitochondria. NDMA demethylation, followed by nonenzymatic cleavage of the hydroxylated methyl group gives formaldehyde and methyldiazohydroxide and then leads to the formation of, a methonium ion, which is able to methylate nucleophilic sites of cellular macromolecules such as, proteins, RNA and DNA. A lot of studies suggest the existence of an alternative pathway to the formation of a methylating agent, denitrosation. Although the nature of mechanisms of denitrosation is not completely known, authors think that the formation of nitrite may represent a detoxification pathway rather than an activation pathway.

Animals↗
PubMedDate not supplied

[Acquired neonatal herpes].

The authors report a case of neonatal herpes simplex infection with favourable outcome, without any sign of meningo-encephalitis or dissemination. The child was given antiviral treatment with Acyclovir from the first day of rash. Vesicle scraping and a complete serologic study of both child and mother proved infection was due to herpes simplex virus type I, transmitted to the neonate during primary maternal infection with gingivostomatitis beginning on the day of delivery. The different routes of postnatal contamination of the neonate by herpes virus and the risks of dissemination are reviewed. The importance of preventing contamination and dissemination of a known herpetic infection in maternity-hospitals and in nurseries for newborns is emphasized. Antiviral treatment should be used in all neonates with localized herpetic infection.

Female↗
PubMedDate not supplied

[Quality of health services in Africa : example of dystocia prenatal screening in Nioki (Zaire)].

Childbirth, though a common yet highly valued social event in Africa, is a major risk for the mother and child. During these last few decades, extension of health services has gained attention and their accessibility has improved. However, these health services remain inefficient because of their poor quality, especially for prenatal screening. This study with 59 cases and 177 controls was carried out in a rural district of Zaire. The objectives were to first assess the quality of the diagnosis of high risk pregnancy (HRP) and secondly to identify the main risk factors associated with complicated deliveries. The diagnosis of HRP has a low sensitivity (53%) yet a high specificity (95%). The diagnosis is based on postpartum hemorrhage and maternal height but does not consider primiparity or previous complicated deliveries. By improving the use of currently available information, a higher sensitivity (72%, could be obtained, identifying close to 3 out of 4 HRPs, but with a lower specificity (67%). The current diagnosis is conservative, partly because health personnel are reluctant to refer pregnant women, who could deliver normally, to the district hospital. Predictive criteria of complicated pregnancy are: primiparity, maternal height, previous difficult childbirth (dystocia), previous postpartum hemorrhage and lack of prenatal care. Prenatal screening should be a major component of safe motherhood programs. Our results show that in developing countries where emphasis is mainly put on the accessibility of health services, the quality of these services should become a priority. Quality is linked to efficiency, yet good quality gives a better image of services and improves compliance of the women.

Adolescent↗