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Biomedical subjects

D Vincent

Publications and source records attributed to D Vincent.

At least 127 records · Page 7Linked to original sources

[Cholinesterases (acetyl and pseudocholinesterase) in human amniotic fluid].

Study on 41 cases. The cholinesterasic activity of human amniotic fluid, free from blood, is very weak, in average 0,10 microkatal, approximatively 300 times weaker than mother's serum. In this "total cholinesterase", we find a large amount (about 40%) of acetylcholinesterase. Amniotic cholinesterases have an prominent placentary origin, with, in addition, a likely activity proceeding from cellular elements.

Acetylcholinesterase↗

Microfilamentous system and secretion of enzyme in the exocrine pancreas. Effect of cytochalasin B.

The microfilaments in the acinar cell of the exocrine pancreas are essentially located in the apical part of the cell: thin microfilaments (50 A), cytochalasin B (CB)-sensitive, form the axis of the microvilli and a network lying beneath the apical membrane; thicker filaments (100 A), at least partly CB-insensitive, form bundles parallel to the plasma cell membrane and the desmosomal links. CB interaction with the acinar cell of the exocrine pancreas involves at least two sites: a membrane site involved in the inhibitory effect of CB on the monosaccharide transport and a less sensitive site at the filamentous level at least partly responsible for the inhibitory effect of CB in the secretion of the exportable enzyme from the pancreatic cell. CB did not alter the energy balance of the acinar cell nor the exchanges of 15-Ca between the extracellular medium and the pancreatic tissue. CB (2 times 10-minus 7 and 2 times 10-minus 6 M) has secretagogue properties whereas CB (2 times 10-minus 5 M) has inhibitory effect on stimulated secretion and secretagogue properties. The mechanism of these secretory effects is not yet explained. The analysis presented in this investigation affords strong evidence for the involvement of the microfilamentous network in the last steps of the secretory cycle in the acinar cell of the exocrine pancreas.

Adenosine Triphosphate↗

[Amniotic fluid arginase in women at term].

Study on 34 cases. A considerable arginasic activity is observed in amniotic fluid in women at the end of pregnancy. This activity is weak, but increased by Mn2+ (about 5 to 8 times). The total amniotic fluid is more active than the surpernatant, the deposit of which has been eliminated. An important part of arginasic activity results from the elements of the deposit (amniotic cells, foetal cells and eventualy erythrocytes in hemorragic amniotic fluid).

Amniotic Fluid↗