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J M Pleau

Publications and source records attributed to J M Pleau.

31 records · Page 2Linked to original sources
PubMed1981

[Role of zinc and other metals in the biological activity of the serum thymic factor (thymulin)].

The serum thymic factor (FTS) used in synthetic or natural form, loses its biological activity after passage on a chelating agent, Chelex 100. Such activity is recovered after addition of zinc and, to a lesser degree, of certain other metals. FTS activation is secondary to zinc binding to the peptide. These results indicate the existence of two FTS forms: the first one, deprived of zinc and biologically inactive, the second one containing zinc and biologically active, for which we purpose to coin the name of thymulin.

Animals↗
PubMed1980

Cytoplasmic localization of FTS (facteur thymique sérique) in thymic epithelial cells. An immunoelectronmicroscopical study.

This study was concerned with the localization of the facteur thymique sérique (FTS) by immunoelectronmicroscopy in cultured thymic epithelial cells. The FTS antibodies labelled differently sized cytoplasmic vacuoles containing a substance of variable density. This substance occurs occasionally in crystalline structures which reacted strongly with purified FTS antibodies. On the ultrastructural level the FTS-positive cells were demonstrated to fix specifically keratin antibodies and to contain tonofilaments. Some of these cells originated from the thymic medulla proved by the presence of microvilli-forming cytoplasmic vacuoles. The existence of FTS-positive crystalline inclusions confirmed the hypothesis of a storage process in the cytoplasm of thymic epithelial cells in vitro or in pathological conditions.

Animals↗
PubMed1977

Structural study of circulating thymic factor: a peptide isolated from pig serum. I. Isolation and purification.

A circulating thymic factor (FTS) has been characterized by a bioassay based on its ability to render theta-negative rosette-forming cells theta-positive and azathioprine-sensitive. FTS was sequentially purified and finally isolated from 1000 liters of pig serum by ultrafiltration, gel filtration, and ion exchange chromatography. Its amino acid composition and apparent molecular weight estimated by Sephadex G-25 chromatography, indicate that FTS is a nonapeptide of composition lysine, aspartic acid (or asparagine), serine 2, glutamic acid (or glutamine) 2, glycine 2, and alanine.

Amino Acids↗
PubMed1977

Structural study of circulating thymic factor: a peptide isolated from pig serum. II. Amino acid sequence.

The amino acid sequence of a circulating thymic factor (FTS, facteur thymique sérique) isolated from pig serum has been established as less than Glu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn-OH. This sequence was obtained by Edman analysis both on the intact peptide and after tryptic digestion. The COOH-terminal residue was identified by carboxypeptidase A digestion. A synthetic peptide was prepared which showed the same biological activities as native pig circulating thymic factor, thus confirming the proposed primary structure.

Amino Acid Sequence↗
PubMed1977

[De novo purine biosynthesis. In vitro measurement in hyperuricemia (author's transl)].

De novo purine biosynthesis has been investigated in circulating blood lymphocytes in vitro. N-formyl-glycinamide ribonucleotide (FGAR) has been mesured using 14C-formate incorporation in the presence of azaserine, a metabolic inhibitor blocking the metabolical pathway at the level of FGAR synthesis. Such a synthesis was measured in 20 healthy controls, 24 patients with primary gout (11 on allopurinol therapy) and 26 patients with chronic renal failure and secondary hyperuricemia (8 on allopurinol therapy). Among gouty patients without allopurinol therapy, FGAR synthesis was normal in 5 and increased in the others. FGAR synthesis was decreased in patients with renal failure whatever the therapy. However, FGAR synthesis remained increased in patients with a primary gout complicated with renal insufficiency. The test we propose for de novo purine biosynthesis measurement is simple and of value to analyse the patho-physiology of hyperuricemia and its therapy. The test allows an acurate discrimination between primary and secondary hyperuricemia in the presence of renal insufficiency.

Adult↗
PubMed1976

[Biochemical characterization of a circulating thymic factor].

A serum thymic factor has been isolated from pig serum. Its amino-acid sequence has been determined by Edman technique, modified by Gray: Gln-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn. A nonapeptide, synthesized on the basis of this sequence is active in the rosette assay used for the isolation of the biological product, both in vitro (10(-15) M) and in vivo (0.1 ng per Mouse).

Amino Acid Sequence↗