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Biomedical subjects

V L Go

Publications and source records attributed to V L Go.

At least 307 records · Page 17Linked to original sources
PubMed1975

25-Hydroxyvitamin D3: evidence of an enterohepatic circulation in man.

Within 24 hr after intravenous administration of isotopic 25-hydroxyvitamin D3 to three normal adults for kinetic studies, one-third of the radioactivity was secreted into the lumen of the duodenum, probably with the bile. The subsequent intestinal reabsorption of over 85% of secreted radioactivity suggests that this major metabolite of vitamin D has a hitherto unrecognized enterohepatic circulation. Our observation of a dynamic hepatic secretion and intestinal reabsorption of radioactivity administered as 3H-labeled 25-hydroxyvitamin D3 to vitamin D-replete man is indicative of an enterohepatic circulation that may be of physiologic importance. It is conceivable that interruption in the recycling of 25-OH-D3 may be an important mechanism of acquired deficiency of vitamin D in gastrointestinal disease.

Adult↗
PubMed1975

Stimulation tests for diagnosis of medullary thyroid carcinoma.

We compared the maximal calcitonin secretion produced by pentagastrin, calcium, and glucagon for preoperative detection of medullary thyroid carcinoma in four subjects with normal or slightly increased plasma immunoreactive calcitonin (iCT) levels. In each case, pentagastrin administration produced higher peak iCT levels (5- to 36-fold increases over basal) than did calcium infusion (by 1.9- to 10.3-fold) and glucagon administration (by 3.6- to 27.4-fold). These preliminary studies suggest that pentagastrin is an effective agent for use in rapid stimulation tests designed to detectmedullary thyroid carcinoma in asymptomatic patients who have normal basal iCT concentrations.

Adolescent↗
PubMed1975

Control of gastric emptying by osmolality of duodenal contents in man.

During the steady state perfusion of the duodenum, recovery of a duodenal marker (polyethylene glycol 4000) can be used to quantify intraduodenal volumes. We used this technique to measure and time the recovery from the duodenum of a second nonabsorbable marker, phenol red. When liquid test meals containing phenol red were placed in the stomach, the rate of gastric emptying could be quantified from the appearance of the maker in the duodenum. The osmolality of either test meal or duodenal perfusates was then varied so that the osmotic control of gastric emptying could be examined. Gastric emptying was fastest when duodenal contents were isotonic; nonisotonic duodenal contents slowed emptying whether these conditions were achieved by nonisotonic duodenal perfusates or by emptying of a nonisotonic test meal. However, nonisotonic solutions in the stomach and in the jejunum did not slow gastric emptying, so long as duodenal contents were isotonic. Osomoreceptors, which slow gastric emptying, are present in the duodenum but not in the jejunum or stomach.

Adult↗
PubMed1975

Serum alpha-fetoprotein in patients with neoplasms of the gastrointestinal tract.

Serum alpha-fetoprotein levels were measured by a sensitive double-antibody radioimmunoassay in 580 patients with a variety of malignant and nonmalignant gastrointestinal diseases to determine the incidence of levels elevated above 40 ng/ml. Over 200 normal control subjects have all had levels below 40 ng/ml. Fifteen % of 95 patients with gastric carcinoma, 3 percent of 191 patients with colorectal carcinoma, 24 percent of 45 patients with pancreatic carcinoma, 25 percent of 8 patients with biliary tract carcinoma, and 70 percent of 73 patients with hepatocellular carcinoma had elevated serum alpha-fetoprotein. None of 14 patients with esophageal or small bowel carcinoma had elevated levels. In contrast, 1 percent of 154 patients with nonmalignant, nonhepatic gastrointestinal disease had elevations of serum alpha-fetoprotein. Alpha-Fetoprotein appears to be a potential marker for tumor activity in some patients with certain gastrointestinal cancers.

Adult↗
PubMed1973

Interactions between intraluminal bile acids and digestive products on pancreatic and gallbladder function.

Interactions between bile acids (taurocholate, TC; taurochenodeoxycholate, TCDC; or taurodeoxycholate, TDC) and digestive products (essential amino acids, EAA or monoolein, MO) in the lumen of the proximal small bowel, affecting pancreatic enzyme secretion and gallbladder contraction, were studied in 77 healthy volunteers by a perfusion method. Perfusion of EAA or MO caused significant increases in pancreatic enzyme output together with gallbladder contraction; MO was more potent and induced enzyme outputs comparable to the maximal response attained with intravenous cholecystokinin-pancreozymin (CCK-PZ). Perfusion of TC alone had no effect, but addition of 10 mM of either TC, TCDC, or TDC to perfusates containing EAA, or 10 mM TC to MO, or both significantly reduced pancreatic enzyme output and prevented gallbladder contraction. A lower concentration of TC (5 mM) added to EAA also produced a significant inhibitory effect. Inhibition of the stimulatory action of digestive products occurred in the jejunum as well as in the duodenum. The inhibitory action of bile acid was considered to be intraluminal since (a) bile acid did not modify the effects of CCK-PZ given intravenously; and (b) the stimulatory effect of digestive products perfused in the duodenum on pancreatic and gallbladder function was not influenced by simultaneous perfusion of bile acid in the jejunum. It is proposed that this inhibitory effect of bile acid is mediated through inhibition of CCK-PZ secretion by high intraluminal concentrations of bile acid. Inhibition of CCK-PZ secretion by bile acid may contribute to the regulation of pancreatic and gallbladder function during digestion by reducing pancreatic enzyme secretion and permitting the gallbladder to refill after evacuation of its contents.

Adult↗