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F Lefèvre

Publications and source records attributed to F Lefèvre.

63 records · Page 4Linked to original sources
PubMedDate not supplied

Interferon-delta: the first member of a novel type I interferon family.

We have recently described a novel type I interferon (IFN) co-expressed with IFN-gamma by the trophectoderm of the pig conceptus between day 12 and day 18 of gestation, a development stage that corresponds to implantation in the uterus. This IFN, now officially named IFN-delta, is recognized as the first member of a novel type I IFN family. This paper reviews the main published data on IFN-delta, together with some new data, showing that IFN-delta, while being a true type I IFN, has some very specific structural and biological properties. Sequences related to IFN-delta coding sequence were found in the genome of man and other ungulates but the only other potentially functional gene was found, so far, in the horse. The pig IFN-delta mature protein, with 149 amino acids, is the smallest of all known type I IFNs. It is unusually rich in cysteines (seven residues), and has a very basic isoelectric point. Recombinant IFN-delta expressed in insect cells is glycosylated and has a high antiviral activity on porcine cells, but not on human cells. It has high antiproliferative activity, which is significantly enhanced in the presence of IFN-gamma. This new IFN was shown to bind on pig cells to the same type I receptor as IFN-alpha. IFN-delta and IFN-gamma genes are co-regulated in the pig trophectoderm, whose cells on day 14-16 of development simultaneously secrete both IFN proteins. The biological role of porcine IFN-delta in early pregnancy has been found unrelated to the known antiluteolytic effect of trophoblastic IFN-tau in ruminants.

Amino Acid Sequence↗
PubMedDate not supplied

Evidence of variation in segregation patterns within a Cedrus population.

We used horizontal starch-gel electrophoresis for a genetic analysis of isozymes within one French Cedrus atlantica stand. Eleven to 29 megagametophytes per tree from 186 trees were assayed. Among the 33 enzyme systems tested, 15 correctly resolved and 8 appeared variable in at least one zone of activity: ACP, GOT, IDH, LAP, MDH, MNR, PGI, and SKDH. They were coded by at least 12 polymorphic loci which were described and tested for Mendelian segregation and linkage. Segregation patterns and linkage relationships were variable in the population. We detected homogeneous segregation distortion for loci Idh, Acp-c, and Got-a over the whole set of segregating progeny. We also found segregation distortions in a significant proportion of progeny for loci Got-b, Mdh-c, Pgi-b, and SKDH: The Acp-c and Got-b loci were linked with an overall map distance of 17 cM, but distance varied drastically among progeny. Both segregation distortions and heterogeneity of recombination frequencies indicate the occurrence of a genetic load in this population.

Chromosome Segregation↗
PubMedDate not supplied

Drug compliance and the elderly: who is publishing, where, and when?

Population aging has occurred in a rather heterogeneous way worldwide. The increasing size of the elder age group highlights various health-related problems for the elderly. One such issue is non-compliance with drug prescriptions, a potential source of serious, even life-threatening problems for the patient. The authors have proposed to identify and rank countries that develop research on drug compliance among the elderly, relevant periodicals, and the frequency articles were published between January 1987 and December 1997. A descriptive study was carried out on the basis of a bibliographical review. Three databases were surveyed: MEDLINE, SOCIOFILE and LILACS. The sample included 440 articles, limited to the behavioral sphere. The number of periodicals recorded was 255, varying from one to tem articles. The number of articles published during the study period varied from 23 in 1987 to 49 in 1992, dropping to 29 in 1997. Frequency of the number of articles/year was erratic up to 1992, leveling off from 1993 on at more than double the baseline figure. The authors emphasize the need for developing multi-focused research worldwide.

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