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S Coulon

Publications and source records attributed to S Coulon.

7 recordsLinked to original sources
PubMed2001

Specific photoaffinity-labeling of Tyr-50 on the heavy chain and of Tyr-32 on the light chain in the steroid combining site of a mouse monoclonal anti-estradiol antibody using C3-, C6-, and C7-linked 5-azido-2-nitrobenzoylamidoestradiol photoreagents.

A mouse monoclonal anti-7-(O-carboxymethyl)oximinoestradiol antibody 9D3, raised against the same immunogen as that employed for generating the reported anti-estradiol antibody 15H11 [Rousselot, P., et al. (1997) Biochemistry 36, 7860-7868], was found to exhibit an opposite specificity profile with a much stronger recognition of the D-ring than of the A-ring extremity of the steroid, but a similar lack of specificity for both 6- and 7-positions of the B-ring. This antibody was photoaffinity-labeled with five (5-azido-2-nitrobenzoyl)amido (ANBA) derivatives of [17alpha-(3)H]estradiol, synthesized from 3-aminoethyloxy, 3-(aminoethylamido)carboxymethyloxy, 6alpha- and 6beta-amino, and 7-[O-(aminoethylamido)carboxymethyl]oximino precursors. After tryptic digestion, the radioactive peptides on L and H chains were immunopurified with the immobilized antibody 9D3, separated by reversed-phase liquid chromatography, sequenced, and characterized by mass spectrometry, including post-source decay-matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The long 3-(ANBA-ethylamido)carboxymethyl ether photoreagent was found to label TyrL-32 (on CDR L1), whereas no labeling was observed with the shorter 3-derivative, a result in agreement with a binding pocket large enough to explain the high cross-reactivity with estradiol 3-conjugates. The two 6alpha- and 6beta-ANBA-estradiol isomers, as well as the 7-[O-(ANBA-ethylamido)carboxymethyl]oximinoestradiol photoreagent derived from the steroid hapten, labeled the same TyrL-32 residue. The 6beta-ANBA epimer also labeled TyrH-50 (at the basis of CDR H2). These experiments indicate that TyrL-32 is freely accessible from the three C3, C6, and C7 positions, all presumed to be exposed to solvent, while TyrH-50 is probably located on the beta-face of estradiol. These results, obtained in solution, provide experimental data useful for molecular modeling of the steroid-antibody complex.

Amino Acid Sequence↗
PubMed1999

A French monitoring programme for determining ochratoxin A occurrence in pig kidneys.

Ochratoxin A is a carcinogen and nephrotoxin which can enter the food chain resulting in human exposure. As pig herds are exposed to ochratoxin A through their feed, their kidneys, livers and pork meat are considered as a possible route of exposure for humans. France, an important producer of pork and pork products, set up a national monitoring programme which included the training of six routine public laboratories in the analysis of ochratoxin A using an immunoaffinity step followed by a HPLC-fluorimetric detection. The programme randomly sampled 300 healthy and 100 nephropathic pig kidneys in 1997 and 710 healthy pig kidneys in 1998. Less than 10% of samples were significantly contaminated by ochratoxin A : in the 1997 survey, 1% of samples contained 0.40-1.40 microg kg(-1) of ochratoxin A and in the 1998 survey 7.6 % exhibited ochratoxin A levels in the range 0.5-5 microg kg(-1). In the case of nephropathic kidneys, only traces of ochratoxin A (0.16 to 0.48 microg kg(-1)) were detected in six samples out of 100. Even if not a major route of exposure for humans, pigs are clearly exposed to this mycotoxin and monitoring of pork products and of feed for swine is necessary.

Animals↗
PubMed1999

[Effect of a standardized acupuncture treatment on complains, blood pressure and serum lipids of hypertensive, postmenopausal women. A randomized, controlled clinical study].

BACKGROUND: Acupuncture according to the Chinese syndrome is often used in patients with postmenopausal complaints. Often these patients have an increased blood pressure. As experienced therapists report that acupuncture is efficient also in hypertension, our aim was to investigate whether the acupuncture used for the treatment of postmenopausal syndrome also has an effect on blood pressure. PATIENTS AND METHODS: The efficacy of a standardized acupuncture according to the Chinese syndrome was evaluated in a randomized, single-blind, placebo-controlled cross-over study with 10 postmenopausal patients with mild hypertension. Blood pressure was measured by 24-hour ambulatory blood pressure measurement. Complaints and well-being were evaluated by validated questionnaires. In addition, serum lipids and excretion of catecholamines in the 24-hour urine were measured. RESULTS: Blood pressure was altered neither by verum nor placebo acupuncture, however, complaints were significantly reduced and well-being was improved after verum treatment. The improvement lasted less than two months. Serum lipids did not change, but the excretion of normetanephrine was reduced by verum acupuncture. CONCLUSIONS: Acupuncture with a standardized combination of acupuncture points according to the Chinese syndrome can transitorily reduce postmenopausal complaints, but does not alter blood pressure or serum lipids at the same time.

Acupuncture Therapy↗
PubMed1998

Improving the affinity and the fine specificity of an anti-cortisol antibody by parsimonious mutagenesis and phage display.

Immunoassays are widely used to determine steroid concentrations. However, they are limited by the specificity of antisteroid mAbs. We used the phage display system combined with molecular modeling and site-specific randomization to improve the affinity and the fine specificity of an anti-cortisol mAb. Using parsimonious mutagenesis, we have generated a library of mutant Ab fragments (scFv) derived from this Ab by randomizing five amino acids chosen by molecular modeling and Ab-hapten contact structural analysis. Anti-cortisol Ab fragments were selected from the library in the presence of steroid analogues to block cross-reacting binders. Specific elution with free cortisol allowed the recovery of clones with up to eightfold better affinity and fivefold less cross-reactivity than the wild-type scFv. This approach can be applied to any anti-hapten Ab and represents a useful approach for obtaining highly specific Abs for use in steroid immunoassays.

Amino Acid Sequence↗
PubMed1998

Identification of streptococci to species level by sequencing the gene encoding the manganese-dependent superoxide dismutase.

We have used a PCR assay based on the use of degenerate primers in order to characterize an internal fragment (sodA(int)) representing approximately 85% of the genes encoding the manganese-dependent superoxide dismutase in various streptococcal type strains (S. acidominimus, S. agalactiae, S. alactolyticus, S. anginosus, S. bovis, S. constellatus, S. canis, S. cricetus, S. downei, S. dysgalactiae, S. equi subsp. equi, S. equi subsp. zooepidemicus, S. equinus, S. gordonii, S. iniae, S. intermedius, S. mitis, S. mutans, S. oralis, S. parasanguis, S. pneumoniae, S. porcinus, S. pyogenes, S. salivarius, S. sanguis, S. sobrinus, S. suis, S. thermophilus, and S. vestibularis). Phylogenetic analysis of these sodA(int) fragments yields an evolutionary tree having a topology similar to that of the tree constructed with the 16S rRNA sequences. We have shown that clinical isolates could be identified by determining the positions of their sodA(int) fragments on the phylogenetic tree of the sodA(int) fragments of the type species. We propose this method for the characterization of strains that cannot be assigned to a species on the basis of their conventional phenotypic reactions.

Base Sequence↗