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Biomedical subjects

V L Go

Publications and source records attributed to V L Go.

At least 253 records · Page 14Linked to original sources
PubMed1978

Direct effect of insulin on secretion of insulin, glucagon, gastric inhibitory polypeptide, and gastrin during maintenance of normoglycemia.

The direct effect of insulin on the secretion of insulin (as measured by C-peptide), glucagon, gastric inhibitory polypeptide, and gastrin was studied in normal subjects by infusing insulin while the plasma level of glucose was maintained in the normal fasting range (euglycemic clamp). Insulin-induced hypoglycemia resulted in increases in circulating glucagon and gastric inhibitory polypeptide, a decrease in C-peptide, and no change in gastrin levels. In contrast, during the euglycemic clamp, insulin was found to behave a direct suppressive effect on the secretion of glucagon, C-peptide, and gastrin, but no effect on levels of gastric inhibitory polypeptide.

Blood Glucose↗
PubMed1978

Intestinal nutrient influence on the enteroinsular axis.

The gastrointestinal contribution to carbohydrate metabolism includes carbohydrate absorption and the release of gastrointestinal hormones that interact with the endocrine pancreas. To learn the contributions to the enteroinsular axis from different levels of the gastrointestinal tract and different nutrients in chyme, we determined serum concentrations of glucose, gastric inhibitory peptide (GIP), insulin, and glucagon postprandially in six normal subjects who underwent diversion of chyme just proximal to an occlusive balloon at the ligament of Treitz and jejunal infusion of saline or chyme carbohydrate, protein, and lipid, separately or in combination. Postprandial elevations of serum glucose, GIP, and insulin and decrease of serum glucagon were elicited predominantly from the bowel and its contents distal to the ligament of Treitz. In this segment, each chyme nutrient (but especially carbohydrate) significantly stimulated factors affecting carbohydrate metabolism. Protein and lipid were able to block carbohydrate-induced glucagon inhibition. The gastroduodenal segment, although containing several proposed insulinotropic hormones (gastrin, secretin, and cholecystokinin), had no effect on serum glucose of glucagon and stimulated only small insulin and GIP responses.

Adult↗
PubMed1978

Serial plasma carcinoembryonic antigen measurements in the management of metastatic colorectal carcinoma.

Serial carcinoembryonic antigen (CEA) measurements were evaluated in a group of 263 patients undergoing systemic chemotherapy for metastatic colorectal carcinoma. Initial CEA levels were not found to be of value in predicting the likelihood of subsequent tumor response. Although a general relation between serial CEA measurements and clinical tumor measurements was noted, these measurements were discordant in a substantial proportion of patients. Tumor measurements as an index of response to therapy were strongly correlated with survival, whereas changes in CEA values and patient survival were not correlated at a statistically significant level. Serial CEA measurements were perhaps of some value in predicting progression of malignant disease, and were roughly comparable to serum alkaline phosphatase assay in assessing response of liver metastasis to chemotherapy. Overall, serial CEA measurements added little to the standard clinical assessment of patients with advanced colorectal carcinoma receiving chemotherapy.

Alkaline Phosphatase↗
PubMed1978

Rationale for the use of cimetidine in pancreatic insufficiency.

The failure of standard oral pancreatic enzyme replacement therapy to correct malabsorption in patients with advanced pancreatic insufficiency is likely due to acid-peptic inactivation of ingested enzymes. Theoretically, the use of cimetidine, an H2-receptor antagonist, in conjunction with oral enzymes, would permit greater transgastric passage of ingested enzymes with resulting improvement in intraluminal lipolysis. To test this hypothesis, we studied the effects of orally administered cimetidine in two groups of patients by utilizing a previously validated double-marker perfusion technique. Cimetidine, in varying doses, had no effect on postprandial exocrine pancreatic function in 16 duodenal ulcer patients without pancreatic disease. In six patients with pancreatic insufficiency, cimetidine produced a pronounced decrease in the output of gastric acid and secretory volume, resulting in reduction of postprandial acidity and intragastric volume. These actions of cimetidine should retard or prevent inactivation of ingested enzymes and also increase their intragastric concentration, with resulting enhancement of luminal duodenal enzyme activity. Supplemental cimetidine may thus be useful in the medical management of patients who fail to respond to routine pancreatic extract therapy alone.

Adult↗
PubMed1978

Stimulation of adenylate cyclase in homogenates of isolated intestinal epithelial cells from hamsters. Effects of gastrointestinal hormones, prostaglandins, and deoxycholic and ricinoleic acids.

The mechanism by which intestinal secretagogues evoke fluid secretion in the small bowel and colon has been suggested to involve mucosal adenylate cyclase. Adenylate cyclase activity was assayed by conversion of [32P]ATP to [32P]cyclic AMP in a system of pure epithelial cells isolated from the small intestine of the hamster by vibration in buffer. Several gastrointestinal hormones were tested for their capacity to stimulate adenylate cyclase; vasoactive intestinal peptide and impure cholecystokinin-pancreozymin (but not the 99% pure preparation or pure cholecystokinin octapeptide) were potent stimuli, but pentagastrin, glucagon, secretin, and gastric inhibitory peptide were impotent. Two prostaglandins, PGE1 and PGE2, were potent stimuli of adenylate cyclase. Two other compounds that provoke intestinal secretion of fluid, deoxycholic acid and ricinoleic acid (castor oil), were ineffective stimuli of adenylate cyclase. These experiments do not support a clear-cut relationship between a compound's ability to stimulate adenylate cylase and its activity as an intestinal secretagogue.

Adenylyl Cyclases↗
PubMed1978

Inhibitory role of the distal small intestine on the gastric secretory response to meals in man.

The role of the distal small intestine on postprandial gastric function was determined in 6 healthy volunteers by diverting chyme from the intestine at a site 100 cm distal to the ligament of Treitz and comparing the results with those observed in the same subjects when chyme was exposed to the entire gut. Diversion of chyme increased the gastric secretory response, which suggests that the distal small intestine has an inhibitory role in postprandial gastric secretion.

Adult↗
PubMed1978

Effects of pentagastrin, G17, and G34 on the electrical and mechanical activities of canine antral smooth muscle.

Intracellular microelectrode technique and standard organ bath technique were used to investigate the effects of pentagastrin, G17, and G34 on the electrical and mechanical activities of canine antral circular muscle. All three molecular forms increased the amplitude and duration of the plateau of the gastric action potential and the frequency of spontaneous action potentials. They also increased the amplitude and frequency of spontaneous contractions. G17 was equal to or less potent than pentagastrin in all of its actions on this tissue. G34 had an equal or greater activity than G17. The electrical studies indicate that G17 is active in this tissue in a physiological range of concentrations. The ED50 for the effect of G17 to increase the amplitude of the plateau potential is less than that for the effect of G17 on gastric secretion, indicating that this is a physiological action of gastrin. Atropine studies indicate that only part of the in vitro inotropic action of gastrin is caused by the release of acetylcholine from nerve terminals, but that the chronotropic action is attributable to a direct effect on the smooth muscle membrane.

Action Potentials↗
PubMed1978

Amino-terminal sequence of a carcinoembryonic antigen-like glycoprotein isolated from the colonic lavages of healthy individuals.

A glycoprotein has been isolated from the colonic lavages of healthy individuals that is immunologically equivalent to carcinoembryonic antigen purified from tumor tissue. The NH2-terminal sequence of the glycoprotein from normal colon lavages is Lys-Leu-Thr-lle-Glu-Ser-Thr-Pro-Phe-(Asn)-Val-Ala-Glu-Gly-Lys-Glu-Val-(Leu,lle)-(Leu,lle)-(Leu,lle)-Val-(His,Arg?)-?-(Leu,lle). This is homologous to the NH2-terminal sequence of 23 of the first 24 amino acids of carcinoembryonic antigen isolated from tumor tissue.

Amino Acid Sequence↗
PubMed1977

Comparative effects of antacids, cimetidine and enteric coating on the therapeutic response to oral enzymes in severe pancreatic insufficiency.

To provide a rational basis for pancreatic enzyme replacement therapy, we evaluated, in six patients with advanced pancreatic insufficiency, the effects of various treatment regimens on fecal fat and nitrogen balance and on duodenal recovery of ingested pancreatic enzymes after a solid test meal. The combination of cimetidine (an H2-receptor antagonist) and pancreatin, each given by mouth, produced significantly higher postprandial duodenal recoveries and concentrations of trypsin and lipase (P less than 0.05). Steatorrhea was reduced in all patients and abolished in four of the six. In the dosages used, neither enteric-coated enzymes nor supplemental neutralizing antacids were more effective than pancreatin alone in decreasing steatorrhea or improving duodenal enzyme delivery. Cimetidine may be a useful adjunct to oral pancreatic extract therapy in some patients with severe pancreatic insufficiency who fail to respond to pancreatic enzyme replacement alone.

Administration, Oral↗
PubMed1977

A prospective comparison of current diagnostic tests for pancreatic cancer.

In 70 patients suspected of having pancreatic cancer, we prospectively compared results of seven diagnostic tests. Subsequent exploration (of 68) and liver biopsy (of two) demonstrated pancreatic cancer in 30, pancreatitis in seven, nonpancreatic neoplasms in nine and nonpancreatic non-neoplastic disease (or no disease) in 24. For detection of pancreatic disease, the best tests were the pancreatic-function test (cholecystokinin-stimulated enzyme outputs) and ultrasonography. The pancreatic scan was nonspecific (P less than 0.001), and thermography was insensitive (P less than 0.001). Endoscopic retrograde pancreatography and arteriography were significantly more sensitive than cytologic study in diagnosis of pancreatic cancer (P less than 0.001). Therefore, when pancreatic cancer is suspected, abdominal ultrasound should be performed first, and if it is negative, a pancreatic-function test next. A positive result from either test warrants an endoscopic retrograde pancreatography for definitive diagnosis. This sequence identified 88 per cent of patients without pancreatic disease and 89 per cent with pancreatic cancer.

Adult↗
PubMed1977

Fate of orally ingested enzymes in pancreatic insufficiency. Comparison of two dosage schedules.

To assess the fate and efficacy of orally ingested enzymes in pancreatic insufficiency, we administered pancreatin to six patients by two schedules--eight tablets with a standard meal or two tablets hourly--and in six normal controls, quantified duodenal enzyme activity and related inactiviation of ingested enzymes to gastric and duodenal pH; in the six patients we measured malabsorption by fecal balance studies. Postprandially, gastric pH was similar in health and pancreatic insufficiency, and below 4 after 40 minutes. Duodenal pH in pancreatic insufficiency declined to approximately 4 beyond 100 minutes--lower than in health (P less than 0.05). Approximately 22 per cent and 8 per cent of trypsin and lipase activity ingested with either schedule was delivered to the ligament of Treitz. Prandial was as effective as hourly administration in decreasing steatorrhea and perhaps more effective in abolishing azotorrhea, and since it is also more convenient, we recommend it.

Administration, Oral↗
PubMed1977

Immunoglobulin complexes in sera of patients with malignancy.

Sera frour 146 patients with malignancy, 59 normal controls and 42 patients hospitalized with non-malignant diseases were examined by a precipitin test with monoclonal rheumatoid factor (mRF) for the presence of circulating immune complexes containing IgG. Forty-two (29%) of the sera from cancer patients but only two of the sera from patients in each of the control groups contained such material. Similar results were obtained with a radioimmunoassay for immune complexes based on the same mRF. Sera from 23 of 65 patients with metastatic malignancy (35%) had elevated levels of immune complexes by this latter test. The presence of the material was not related to the source of malignancy, presence of carcinoembryonic or hepatitis antigens or of such autoantibodies as rheumatoid factor or anti-DNA. By density gradient ultracentrifugation the reacting material was identified as being of molecular size 19s or greater. It has not yet been further characterized with regard to the nature of any antigens present.

Antigen-Antibody Complex↗
PubMed1977

Increased meal-stimulated gastric acid secretion and serum gastrin after extensive small bowel resection in puppies.

In six beagle puppies provided with vagally denervated pouches of the oxyntic gland area, the effects of massive resection of the small intestine on acid secretion and serum gastrin induced by feeding were studied. The enterectomies produced significant postprandial hypersecretion of acid and hypergastrinemia. A linear correlation existed between the increased acid output and serum gastrin level.

Adult↗