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Biomedical subjects

D L Wingate

Publications and source records attributed to D L Wingate.

At least 127 records · Page 7Linked to original sources
PubMed1975

13-norleucine motilin versus pentagastrin: contrasting and competitive effects on gastrointestinal myoelectrical activity in the conscious dog.

In conscious fasted dogs, with chronically-implanted electrodes in stomach and small intestine, typical aborally-propagated interdigestive myoelectric complexes were induced by the infusion of 13-nor-leucine motilin (13-Nle-M); whereas when the normal interdigestive activity was abolished by the infusion of pentagastrin, the resulting 'postprandial' pattern of activity was not significantly modified by the administration of 13-Nle-M. Results from this study provide further evidence that Motilin as well as Gastrin may be involved in the control of gastrointestinal motility in dogs.

Animals↗
PubMed1974

The effect of glycine-conjugated bile acids on net transport and potential difference across isolated rat jejunum and ileum.

1. Five mM glycodeoxycholate and glycochenodeoxycholate inhibit net fluid transport across isolated rat jejunum and ileum; 5 mM glycocholate does not affect jejunal segments, but arrests fluid transport across ileal segments.2. Inhibition of fluid transport is accompanied by some diminution of mucosal glucose uptake, but translocation of glucose to the serosal surface of jejunal segments persists in the presence of dihydroxy conjugated bile acids.3. Inhibition of fluid transport is accompanied by a marked fall in the glucose-stimulated transmural electropotential difference, within 5 min of mucosal exposure to the bile acids.4. The lactate concentration gradient normally maintained across isolated intestine is abolished when fluid transport is inhibited by conjugated bile acids, even though lactate formation is not greatly reduced.5. These results suggest that inhibition of intestinal fluid transport is reproducible in vitro, and that the inhibition is not associated with increased permeability of the mucosa, but may be associated with altered permeability of the mucosal pole of the enterocyte.6. Although in vitro and in vivo effects of dihydroxy bile acids on fluid transport are similar, the assumption that the mode of action is likewise similar is not justified on present evidence.

Animals↗
PubMed1973

Effect of glycine-conjugated bile acids with and without lecithin on water and glucose absorption in perfused human jejunum.

Perfusion studies were performed in healthy volunteers to test whether the secretory effect of conjugated bile acids, previously shown for the colon, was also present in the jejunum. A perfusion system with a proximal occlusive balloon (and continuous aspiration of duodenal secretions) was used; isotonic test solutions contained glycine-conjugated bile acids with or without lecithin. Fluid movement was measured by changes in the concentration of polyethylene glycol (PEG, mol wt 4,000). Conjugated dihydroxy bile acids inhibited electrolyte and fluid absorption and, at higher concentrations, evoked secretion of an isotonic fluid. Glucose absorption continued, despite fluid secretion, but its rate decreased. The secretory effects of bile acids were abolished by the addition of lecithin to the bile acid solutions. A trihydroxy bile acid (cholylglycine) had no effect on jejunal absorption. Small amounts (6-9%) of conjugated bile acids were absorbed in the jejunum; lecithin was well absorbed (72-90%). The results indicate that dihydroxy bile acids influence salt and water transport in the human jejunum but that this effect may be abolished when a polar lipid such as lecithin is present. We speculate that this effect of bile acids may modify fluid movement in the small intestine postprandially after fat absorption has occurred.

Bile Acids and Salts↗
PubMed1972

A comparison of stable and 14 C-labelled polyethylene glycol as volume indicators in the human jejunum.

Polyethylene glycol (PEG plus (14)C-PEG) was measured turbidimetrically and by liquid scintillation counting to compare the validities of these methods during the use of PEG as a volume indicator of intestinal perfusion studies in man. Use of (14)C-PEG results yielded similar estimates of water absorption or secretion. The simplicity of (14)C counting offers practical advantages to the use of (14)C-PEG as a nonabsorbable marker for perfusion studies in man.

Bile Acids and Salts↗