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Biomedical subjects

E Petit

Publications and source records attributed to E Petit.

At least 73 records · Page 4Linked to original sources
PubMed1992

UV-C irradiation-induced peroxidative degradation of microsomal fatty acids and proteins: protection by an extract of Ginkgo biloba (EGb 761).

After exposure of rat liver microsomes to UV-C irradiation, analysis of membrane fatty acids by gas chromatography confirmed that EGb 761, a drug containing a dosed and standardized extract of Ginkgo biloba, provides effective protection against free radical attack in vitro. This analysis, coupled with thiobarbituric acid (TBA) reaction, permitted qualitative and overall quantitative evaluation of radical-induced damage to polyunsaturated fatty acids (PUFA), as well as evidence of the antioxidant properties of the Ginkgo biloba extract. Assay of thiobarbituric acid reactive substances (TBARS) showed a correlation between TBARS concentration and the state of degradation of the polyunsaturated fatty acids. Mannitol (5.5 mM) did not prevent degradation of microsomal PUFA or malondialdehyde (MDA) production, nor did it prevent polymerization of membrane proteins. Low doses of EGb 761 were found to provide efficient protection of membrane PUFA regardless of individual susceptibility to peroxidation. This protection was accompanied by a decrease in the production of TBARS. EGb 761 also protected membrane proteins from the irreversible polymerization induced by these degradation products, but did not appear to prevent thiols oxidation into disulfide bonds.

Animals↗
PubMed1992

Chromosomal localization of the ovine beta-casein gene by non-isotopic in situ hybridization and R-banding.

The ovine beta-casein gene (CNS2) has been mapped to a specific chromosome band using nonradioactive in situ hybridization and simultaneous fluorescent R-banding. The probe pTZ-E4 was a fragment of the ovine beta-casein gene inserted in the plasmid pTZ18R and labeled with biotin-11-dUTP. It hybridized to band q32 of ovine chromosome 4. The discrepancy between this result and the previous localization of this gene on cattle chromosome 6 may be explained by the very great similarity of the banding patterns of ovine and bovine chromosomes 4 and 6.

Animals↗
PubMed1991

Comparison of RBG-banded karyotypes of cattle, sheep, and goats.

The karyotypes of the three main domestic Bovidae species. Bos taurus, Ovis aries, and Capra hircus, have been investigated by RBG-banding. Primary fibroblast cells were cultured from fetal lung or muscle tissue and collected for chromosome preparation after double thymidine synchronization. Depending on the culture and species, BrdU and FdU were added for 8-11 h or 7-10 h, respectively, before harvest. The chromosomes of the three species were classified and numbered according to standard conventions (ISCNDA, 1989) and compared at different stages of condensation. Within the resolving power of the images obtained, the RBG-banding patterns appear to be very similar, with only minor differences existing between chromosome 9 and the sex chromosomes of cattle and the same chromosomes in the domestic sheep and the goat.

Animals↗
PubMed1989

Lipid and apolipoprotein distribution as a function of density in equine plasma lipoprotein.

1. Equine lipoproteins were isolated from plasma by density gradient ultracentrifugation and apolipoprotein composition determined by SDS-polyacrylamide gel electrophoresis. 2. VLDL and IDL were present at low concentration (0.2 mg/ml). Two apoB components of Mr corresponding to human apoB-100 and one apoB-48-like component were represented in VLDL fraction. 3. LDL-1 and LDL-2 subfractions have displayed an almost equal concentration (0.4 mg/ml). Two apoB-100-like components were the major apolipoproteins in each fraction. Small amounts of apoB-48-like component were detectable in LDL-1 and LDL-2. 4. HDL-2 represented a major class of equine lipoproteins (1.8 mg/ml). ApoA-1-like component was the dominant protein in HDL-1, HDL-2 and HDL-3. Dimeric apoA-II-like components were slightly represented in HDL subfractions. 5. HDL-3 displayed the same apolipoprotein pattern as HDL-1 and HDL-2, but two further minor proteins of Mr 20,000 and 14,000 were detected. 6. VHDL represented a minor class of lipoprotein (0.2 mg/ml). ApoA-I-like component was the major apolipoprotein of VHDL. Small amounts of apoA-IV-like, apoE-like, and Mr 55,000 protein were detectable. 7. ApoC-like of Mr lower than 10,000 was represented in all equine lipoprotein classes.

Animals↗
PubMed1988

Electroimmunoassay of human serum lipoproteins containing Apo A-I by monoclonal antibodies.

Three monoclonal antibodies to human serum apolipoprotein (Apo) A-I (4A12, 4B11 and 2G11) were produced by Sanofi. They were directed to three distinct epitopes of the Apo A-I molecule, present on the surface of the lipoprotein particles. They were able to precipitate individually some lipoprotein units from the serum. Only the mixture of the three monoclonal antibodies could allow a precipitation of all Apo A-I containing particles. An electroimmunoassay using this oligoclonal mixture was assessed to standardize the Apo A-I measurement in serum. Results agreed well with those obtained by electroimmunoassays using polyclonal antisera. Moreover no pretreatment of serum samples with dissociating agents or detergents was required. Therefore, this specific, rapid (7-8 h), precise (within- and between-assay precisions were 4.25 and 3.1%, respectively) immunoassay is routinely available for apolipoprotein A-I measurement in serum.

Antibodies, Monoclonal↗
PubMed1988

Circadian rhythm-varying plasma concentration of 5-fluorouracil during a five-day continuous venous infusion at a constant rate in cancer patients.

A circadian rhythm in the plasma concentration of 5-fluorouracil (5-FUra) is demonstrated in seven patients receiving this drug as a continuous venous infusion at a constant rate for 5 days. All patients had stage C bladder carcinoma and received cis-diamminedichloroplatinum(II) (45-91 mg/m2) on day 1 as a 30-min venous infusion at 5 p.m. Continuous venous infusion of 5-FUra (450-966 mg/m2/day) was started on day 2 at 8:30 a.m. via a volumetric pump and lasted for 5 days (until day 6). Blood samples were obtained on EDTA every 3 h on days 2, 4, and 6 on each patient (20 samples/patient). 5-FUra plasma concentration was determined by high performance liquid chromatography. Data were analyzed by both multiple analysis of variance and cosinor. Mean lowest and highest values (+/- SEM) were, respectively, 254 +/- 33 ng/ml at 1 p.m. and 584 +/- 160 ng/ml at 1 a.m. (F = 2.3; P less than 0.03). Because of large intersubject differences in 24-h mean plasma concentration, data were also expressed as percentages of each patient's 24-h mean. Both analysis of variance and cosinor analysis further validated (P less than 0.0001) a circadian rhythm with a double amplitude (total extent of variation) of 50% of the 24-h mean and an acrophase located at approximately 1 a.m. (estimated time of peak). Such findings warrant a thorough scrutiny at the chronopharmacology of anticancer drugs when designing continuous infusion schedule. A circadian modulation of the infusion rate of this drug may further optimize the therapeutic index of such treatment modality.

Aged↗
PubMed1988

Competitive enzyme inhibition immunoassay of apolipoprotein A-I: use of monoclonal antibodies.

An original competitive enzyme inhibition immunoassay has been developed for determination of total apolipoprotein A-I (apo A-I) in serum and in plasma. This specific assay involves a single monoclonal antibody (F59 4A12 2F4, directed to the -COOH terminal region of the apo A-I molecule) and a stable secondary plasma standard. Delipidation of serum samples exposed no additional antigenic sites, which suggests that all the apo A-I molecules express the epitope detected by Mab 4A12 on the surface of the apo A-I-containing particles. Within- and between-run CVs were, respectively, 6.1% and 7.5% at a 1.47 g/L concentration of apo A-I, 7.1% and 8.2% at 1.21 g/L, and 6.5% and 7.3% at 1.80 g/L. Results (y) correlated with those obtained with an electroimmunoassay (x), in which we used a mixture of three monoclonal antibodies, including Mab 4A12, as follows: y = 250x - 7, r = 0.744, P less than 0.001.

Antibodies, Monoclonal↗
PubMed1987

Monoclonal antibodies to human apolipoprotein A-I: characterization and application as structural probes for apolipoprotein A-I and high density lipoprotein.

Three mouse monoclonal antibodies (Mabs) to human apo A-I were produced using apolipoprotein A-I or HDL3 as immunogens. These monoclonal antibodies, 2G11, 4A12 and 4B11, were characterized for their reactivity with isolated apolipoprotein A-I and HDL in solution. The immunoblotting patterns of the HDL3 two-dimensional electrophoresis show that these three monoclonal antibodies reacted with all the polymorphic forms of apolipoprotein A-I. Cotitration experiments indicated that they correspond to three distinct epitopes. In order to locate these three antigenic determinants on the isolated apolipoprotein A-I, the reactivity of the three monoclonal antibodies has been studied on CNBr-cleaved apolipoprotein A-I. The monoclonal antibodies 2G11 and 4A12 addressed to the amino (CNBr 1) and carboxy (CNBr 4) terminal segments, respectively. In comparison with the monoclonal antibodies characterized by Weech et al. ((1985) Biochim. Biophys. Acta 835, 390-401), monoclonal antibody 4A12 is the only one described in the literature which is specific of the carboxy terminal segment of apolipoprotein A-I. Monoclonal antibody 4B11 does not react with any CNBr fragment, its binding is temperature dependent, it could be directed to a conformational epitope. Relative differences were demonstrated in the expression of the three epitopes in HDL subfractions isolated by density gradient ultracentrifugation. According to Curtiss and Edgington ((1985) J. Biol. Chem. 260, 2982-2993) our results indicate the existence of an immunochemical heterogeneity in the organization of apolipoprotein A-I at the surface of HDL particles as well as in the soluble form of apolipoprotein A-I.

Antibodies, Monoclonal↗
PubMed1986

[Structure and metabolism of lipoproteins].

Lipoproteins constitute in plasma a dynamic system allowing lipid transport. For this purpose, apolipoproteins play a very important part. They control and regulate lipid transfer between lipoproteins themselves and among cells, from their hepatic as intestinal synthesis sites to their hepatic as peripheral degradation sites. Enzymatic systems and specific receptors are involved to operate this metabolic pathway.

Chemical Phenomena↗
PubMed1985

Production of porcine interleukin-2 and its biological and antigenic relationships with human interleukin-2.

A lymphokine obtained from PHA-stimulated porcine blood leukocytes was found to induce the growth of IL2-dependent murine cells: this factor was therefore considered as the porcine lymphokine analogous to IL2. PHA was found to induce higher amounts of IL2 than Con A. Preculture of porcine PBL or addition of indomethacin enhanced IL2 production, suggesting the existence of a prostaglandin-mediated inhibition of IL2 production in fresh PBL cultures. Porcine IL2 could also promote the growth of activated porcine cells whereas it was inactive on human lymphoblastoid cells. A neutralizing polyclonal anti-human IL2 antiserum was also unable to neutralize porcine IL2. These results indicate therefore, that no biological and antigenic cross-reactivities are demonstrable between human and porcine IL2.

Animals↗