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Biomedical subjects

M Ledoux

Publications and source records attributed to M Ledoux.

At least 73 records · Page 4Linked to original sources
PubMed1985

[Comèl's ichthyosis linearis circumflexa: treatment with Ro 10-9359. Electron microscopic study].

The authors show the noteworthy efficacy of the aromatic retinoid Ro 10-9359 in the treatment of ichthyosis linearis circumflexa. The initial dose was 1 mg/kg daily; later on, the maintenance dose was 0.3 mg/kg daily. Ultrastructurally, transitional cells were observed between the granular and the horny layer. After treatment, large perinuclear pseudovacuoles appeared, as well as numerous microvilli.

Adult↗
PubMed1984

[Cat-scratch disease].

A case of cat-scratch syndrome is described. The dermatological features and skin reactions reported in this illness (erythema nodosum, erythema multiforma) as well as the diagnostical criteria are reviewed. The hypothetical nature of the etiologic agent of this syndrome is discussed.

Adult↗
PubMed1983

Isolation and partial characterization of a complex of several (Pro-) endopeptidases from whole porcine pancreatic extract and from purified zymogen granules.

Pancreatic zymogen granules contain exportable proteins at a very high concentration. The mechanism leading to this condensation is unknown. On the other hand, it is known that aqueous extract of pancreatic acetone powder precipitates at low ionic strength and acidic pH. The precipitable fraction is called 'euglobulin' in the literature. We thought that euglobulin could serve as a simplified model to study the condensation of some of the pancreatic exportable proteins. We have compared quantitatively and qualitatively the composition of euglobulins prepared from porcine pancreatic acetone powder and from lysates of purified pancreatic zymogen granules. They were found to be nearly identical, consisting of glycoprotein(s) and/or proteoglycan(s) associated to a proesterase activity, chymotrypsinogens C and D and proelastase. We conclude therefore, that the interactions between the constituents of euglobulin must be specific, since they can occur in the complex protein mixture of the whole organ to a similar extent as in the zymogen granules themselves. We have tried to identify the nature of these specific interactions. We were able to demonstrate that neither the granule membranes, nor the high-molecular-weight proteoglycan present in the granules (Reggio, H.A. and Palade, C.E. (1978) J. Cell. Biol. 77,288-314) were responsible for the observed aggregation. Electrostatic interactions between acidic and basic proteins (Thomson, A. and Denniss, I.S. (1976) Biochim. Biophys. Acta 429, 581-590) were demonstrated between proelastase and chymotrypsinogens C and D. However, the possible roles of the glycoprotein(s) and/or proteoglycan(s) in the condensation process remain unknown.

Amylases↗
PubMed1982

The onset of menarche: a late event in pubertal progression to be affected by physical training.

Several studies have shown that involvement in certain sports activities could lead to a significant delay in the onset of menarche. It is here emphasized that the latter constitutes a late pubertal event and that research in kinanthropology should now focus on processes underlying menarche. Some findings indeed suggest an influence of certain physical activities upon the maturation rate of endocrine axes which lead to the onset of the first menses.

Adrenal Glands↗
PubMed1981

Prolactinemia in exercising male athletes.

8 male collegial athletes were submitted at random to three (55, 70 and 85% of VO2 max) ergocycle exercises of 20-min duration. Venous blood samples were obtained before, during and after ergocycling sessions by antecubital catheterization. Serum prolactin was measured by RIA using specific antiserum. The exercise treatments induced a blood prolactin response proportional to the intensity of the work loads.

Adolescent↗
PubMed1977

Chymotrypsinogen D, a new zymogen from porcine pancreas with proelastolytic activity.

During the purification of propancreatopeptidase E, a proATEEase activity is always copurified. The proelastolytic and proesterolytic activities can be separated on a hydroxylapatite column. The zymogen with potential ATEEase activity has a basic isoelectric point, can be activated by trypsin, and can hydrolyse elastin and ATEE but not ATAME. Its molecular weight is about 26,500 and the NH2-terminal sequence indicates clearly that it belongs to the chymotrypsinogen family, but that it is not chymotrypsinogen A, B, or C. We call it chymotrypsinogen D. Although both pancreatopeptidase E and chymotrypsin D can hydrolyse elastin, the synthetic substrate ATAME is attacked only by pancreatopeptidase E. Therefore, the peptide bonds in elastin cleaved by these two enzymes should be different.

Amino Acid Sequence↗
PubMed1975

Electrophoretic characterization of porcine pancreatic (pro)elastases A and B.

Two porcine pancreatic zymogens can be separated by free electrophoresis on a sucrose gradient. After activation by trypsin, both enzymes can hydrolyze completely the fibrous protein elastin. One of the two proteins, proelastase B, has, in addition, an esterolytic activity towards N-acetyl-L-tyrosine ethyl ester. The other, proelastase A, does not possess it. The activation products of the zymogens have been tagged with radioactive diisopropylfluro-phosphonate and separated by polacrylamide-gel electrophoresis. Proelastase A gives only one active species, pancreatopeptidase E, but three distinct proteins can be obtained from proelastase B. Elastases A and B exhibit an important synergism when acting together upon a purified elastin lacking microfibrils. Trypsin has considerably less synergistic activity, and chymotrypsin has practically none.

Animals↗