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Biomedical subjects

M Roland

Publications and source records attributed to M Roland.

At least 163 records · Page 9Linked to original sources
PubMed1975

Effect of carbacholine and urecholine on pentagastrin-stimulated gastric secretion in healthy subjects.

Dose-response studies of pentagastrin-stimulated gastric secretion were performed in 6 healthy volunteers. On different days pentagastrin was given in doses of 0.15, 1.5, and 15 mug/kg/hr either alone or in combination with carbacholine, 2 mug/kg/hr, or urecholine, 60 mug/kg/hr. Carbacholine and urecholine increased acid and pepsin secretion evoked by the lowest dose of pentagastrin while there was no augmentation at the highest dose. The dose of pentagastrin required to elicit half maximal acid output (Km) tended to decrease by simultaneous infusion of carbacholine or urecholine, suggesting that the cholinomimetics increased the sensitivity of the parietal cells to pentagastrin stimulation. Km for pentagastrin alone was higher than previously found in unoperated duodenal ulcer patients.

Adult↗
PubMed1974

Warfarin. Stereochemical aspects of its metabolism and the interaction with phenylbutazone.

An examination of the metabolic fate of the R and the S isomers of warfarin revealed that the two isomers were metabolized by different routes. R warfarin was oxidized to 6-hydroxywarfarin and was reduced to the (R,S) warfarin alcohol. In contrast, S warfarin was oxidized to 7-hydroxywarfarin and was reduced to the (S,S) warfarin alcohol. S warfarin was also oxidized to 6-hydroxywarfarin. These observations suggested that interactions between warfarin and other drugs might be manifest stereo-specifically, i.e., have a different effect on the isomers of warfarin, so a series of experiments were conducted with each isomer of warfarin, before and after phenylbutazone. The plasma clearance of S warfarin was slowed from 3.1 to 1.1% per h in one subject and from 2.3 to 1.6% per h in another. In contrast, the clearance of R warfarin was increased from 1.5 to 3.0% per h and from 0.9 to 1.6% per h in two subjects after phenylbutazone. The rate of clearance of racemic warfarin was unaffected by phenylbutazone; the depression of the rate of clearance of the S isomer masked the stimulation of the clearance of the R isomer. Since S warfarin is five times more potent an anticoagulant than R warfarin, it is concluded that inhibition of the metabolism of S warfarin provides one mechanism for the augmented anticoagulation which follows phenylbutazone.

Blood Coagulation↗