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Biomedical subjects

V L Go

Publications and source records attributed to V L Go.

At least 235 records · Page 13Linked to original sources
PubMed1979

Simultaneous measurement of antroduodenal motility, gastric emptying, and duodenogastric reflux in man.

In six healthy individuals, the relationship between antroduodenal motor activity, duodenogastric reflux, and gastric emptying were simultaneously examined by combined use of multiple marker perfusion and miniature strain gauge transducers. An interdigestive pattern of motor activity was observed during the fasting period;duodenogastric reflux was of variable magnitude, but reproducible in each individual. Fasting reflux was significantly reduced during phase III of the interdigestive complex. Administration of 0.15 M sodium chloride into the stomach resulted in minor and inconsistent changes in antroduodenal motility, despite the rapid and similar pattern of gastric emptying in the six subjects. This study supports the concept that motor activity in the antroduodenal region does not affect gastric emptying of inert, isotonic fluids but may be involved in the regulation of duodenogastric reflux.

Adolescent↗
PubMed1979

Postprandial gastric function in pancreatic insufficiency.

Abnormalities in postprandial gastric function could contribute to the maldigestion of pancreatic insufficiency. To measure simultaneously postprandial gastric secretion and emptying and correlate these measurements with intraluminal duodenal changes, we performed intestinal intubation and duodenal perfusion during feeding of a solid-liquid test meal in 10 healthy controls and 10 patients with documented pancreatic insufficiency before and after replacement therapy. In pancreatic insufficiency, intraduodenal pH was significantly decreased late in the postprandial period while simultaneously measured duodenal acid loads were normal, confirming that reduced bicarbonate output rather than increased acid delivery was responsible for higher duodenal acidity in these patients. Significant (P less than 0.05) reductions in postprandial acid, pepsin, and total secretory outputs were noted in untreated patients only during the first postprandial hour. Absolute gastric emptying rates were lower in patients (P less than 0.05) than in healthy subjects, but fractional rates of emptying were similar. Fasting and postprandial hypergastrinaemia were consistently observed in the patients with pancreatic disease. There are postprandial disturbances of secretory function but no primary gastric motor defect in patients with exocrine pancreatic insufficiency.

Duodenum↗
PubMed1979

Regulation of calcitonin secretion in normal man by changes of serum calcium within the physiologic range.

To examine the relative importance of calcium and gastrin in regulation of calcitonin secretion, we administered graded oral doses of calcium to 10 normal men, ages 23-29 yr. Each subject had previously shown an appropriate increase in calcitonin secretion in response to a pharmacologic (0.5 mug/kg) pentagastrin injection. On separate days and in random order, each man drank 250 ml of distilled water containing 0.0, 0.5, 1.5, and 3.0 g of elemental calcium as the gluconate salt. Blood samples were drawn before and at 30, 60, 90, 120, 180, and 240 min after the oral calcium dose. The samples were analyzed for calcium by atomic absorption spectroscopy, and for gastrin and calcitonin by radioimmunoassays of established sensitivity and specificity. Ingestion of water (control) caused no change in any of the three variables. Calcium ingestion resulted in dose-related increases, within the normal range, of all three variables. Immunoreactive gastrin rose promptly, peaking at 30 min, and returning to basal levels or below by 120 min. In contrast, calcium and immunoreactive calcitonin levels rose slowly and in parallel, peaking at 120-240 min. Changes in calcitonin and changes in calcium were strongly and positively correlated, r = 0.73, when all data were pooled. Furthermore, individual linear regressions for changes in calcitonin and calcium levels (calculated separately for the three oral calcium doses in each subject) had positive slopes in 28 out of 30 sets (P < 0.01). The changes in calcitonin concentrations were much more poorly correlated with the corresponding changes in serum gastrin levels; in fact, the regression coefficient was weakly negative, r = -0.20. These results show that, at least in young adult men, changes of ambient calcium concentration within the normal range may be of major importance in physiologic regulation of calcitonin secretion. The findings are consistent with the hypothesis that calcitonin functions to prevent excessive postprandial hypercalcemia.

Adult↗
PubMed1979

Pancreatic alpha-cell function in diabetic hemochromatotic subjects.

To clarify further the etiology of the carbohydrate intolerance in idiopathic hemochromatosis, we investigated the glucose, insulin, C-peptide, and glucagon responses to arginine (0.5 g/kg) infused during 30 min in lean normal subjects; in insulin-requiring subjects with hemochromatosis, genetic diabetes, and total pancreatectomy; and in nondiabetic cirrhotic subjects without portosystemic shunting. Serum insulin, C-peptide, and glucagon responses (30K antibody) were determined by RIA, and glucose level was determined by a glucose oxidase technique. Hemochromatotic and genetic diabetic subjects had similar basal glucose (157 +/- 25 vs. 168 +/- 40 mg/dl) and C-peptide (0.73 +/- 0.42 vs. 0.65 +/- 0.22 ng/ml) values, with subnormal C-peptide peak responses to stimulation (1.05 +/- 0.38 and 1.40 +/- 0.83 vs. 3.95 +/- 0.4 ng/ml in normals; P less than 0.05). No glucagon or C-peptide response to arginine was seen in any pancreatectomized subject. Similar but excessive glucagon levels were present in hemochromatosis, diabetes, and cirrhosis under basal conditions (166 +/- 24, 232 +/- 111, and 263 +/- 116 vs. 76 +/- 15 pg/ml; P less than 0.05) and after arginine stimulation (782 +/- 80, 834 +/- 123, and 902 +/- 275 vs. 489 +/- 81 pg/ml; P less than 0.05) when compared with normals. The excessive glucagon levels found in hemochromatosis, diabetes mellitus, and cirrhosis contrast to the absent response in pancreatectomized subjects and indicate that generalized islet cell destruction is not the major factor in diabetic hemochromatotic subjects.

Adult↗
PubMed1979

The relationships between pancreatic ductal obstruction and pancreatic secretion in man.

Precise relationships between pancreatic ductal obstruction and pancreatic secretory capacity have not been established. In this study, we describe the quantitative relationships between the lengths of opacified ducts obtained at retrograde pancreatography and the secretory capcity of the gland for volume, bicarbonate, lipase, and trypsin. Forty-five patients (17 with pancreatic cancer, 6 pancreatitis, 5 other malignancies, and 17 nonmalignant, nonpancreatic disease found at laparotomy) were studied with a method of duodenal intubation and perfusion with basal saline perfusion alone or with continuous intravenous infusion of secretin or of cholecystokinin-pancreozymin. Secretory outputs of volume, bicarbonate, and enzymes compared with the length of opacified ducts showed a significant (P less than 0.05) linear relationship for patients with pancreatic cancer, pancreatitis, and other cancers. The resulting data imply that obstruction of the pancreatic duct is important in decreasing secretion of the pancreas in pancreatic disease. The relationship between obstruction and pancreatic secretion demonstrates that a decrease in exocrine pancreatic secretion cannot be detected until more than 60% of the total length of the main pancreatic duct has been obstructed.

Adult↗
PubMed1979

Antroduodenal motor response to solid-liquid and homogenized meals.

The effect of the physical state of food on antroduodenal motor activity and the pattern of the emptying of an aqueous phase marker were examined in 6 healthy volunteers using an intestinal perfusion technique and intraluminal pressure transducers. Ingestion of a solid-liquid meal produced marked phasic changes in pressure in the distal antrum, lasting 92 +/- 10 min (mean +/- SE), while, in contrast, ingestion of the same nutrients in a homogenized state resulted in complete absence of distal antral changes in pressure lasting 133 +/- 12 min. The motor responses of the proximal antrum and duodenum were similar for the two meals. Both meals emptied during a 3-hr period, the pattern of emptying of the aqueous phase marker being similar for the two meals except for the first 40 min, when emptying was more rapid after the solid-liquid meal. The homogenized meal emptied despite the absence of changes in distal antral pressure. The gastrin response was similar for the two meals and is therefore not responsible for the different patterns of antral motility and gastric emptying.

Adult↗
PubMed1979

Reduced intraluminal bile acid concentrations and fat maldigestion in pancreatic insufficiency: correction by treatment.

Malabsorption of bile acids is known to occur in patients with pancreatic insufficiency particularly when due to cystic fibrosis. Abnormal biliary secretion or intraluminal acidic precipitation of bile acids could contribute to the steatorrhea of pancreatic insufficiency. To measure bile acid outputs and duodenal concentrations of bile salts and lipids simultaneously, we performed intestinal intubation and perfusion studies during feeding of a solid test meal in 6 healthy controls and 8 adult patients with advanced acquired exocrine pancreatic insufficiency. The effects of various treatment regimens were also investigated. Postprandial bile acid secretion was similar in all treatment groups. However, significant (P less than 0.05) reductions in micellar concentrations of bile acids and fatty acids were observed in untreated pancreatic insufficiency. These abnormalities were directly related to pH-induced precipitation of bile acids and were corrected only by the addition of cimetidine to standard pancreatin therapy. Thus, in pancreatic insufficiency, treatment with pancreatin plus cimetidine enhances fat digestion and absorption by reducing both acid-peptic inactivation of lipase and acidic precipitation of bile acids.

Administration, Oral↗
PubMed1979

Gastrointestinal hormone profile in renal insufficiency.

Fasting serum gastrin, cholecystokinin, glucagon, and gastric inhibitory polypeptide concentrations were simultaneously measured in normal subjects and in patients with different degrees of renal failure. Values of gastrin, cholecystokinin, gastric inhibitory polypeptide, and glucagon were significantly higher in all patients with serum creatinine concentrations greater than 3 mg/dl than in controls (P less than 0.01). The degree of renal insufficiency was significantly correlated (P less than 0.05) with serum concentrations of each hormone, but no significant linear correlation existed among the serum concentrations of different gastrointestinal hormones in individuals. Hemodialysis did not significantly alter predialysis serum gastrin, cholecystokinin, or glucagon concentration, but the serum gastric inhibitory polypeptide concentration decreased by 30% (P less than 0.01) after hemodialysis. The disproportionate increases of hormones with antagonistic actions may alter gastrointestinal function in renal insufficiency.

Adult↗
PubMed1978

A prospective evaluation of the leukocyte adherence inhibition test in colorectal cancer and its correlation with carcinoembryonic antigen levels.

Fifty-four patients from the surgical gastroenterology service and 22 healthy controls have been prospectively evaluated in a single-blind protocol by the LAI tube method. The LAI correctly identified 25 of 33 early colorectal patients staged as Dukes' B and C at surgery but none of the Dukes' D patients. An inverse relationship was seen between the results of the non-adherence index (NAI) and CEA levels which was most pronounced in those with advanced colorectal cancer. The majority of Dukes' B and C patients having a "false negative" LAI had a CEA level greater than 2.5 ng/ml, suggesting that more advanced disease than that seen at surgery may be present. Two of 22 normal controls gave a borderline positive NAI. Some technical problems, including the relatively short life of the tumor extracts, are discussed.

Carcinoembryonic Antigen↗
PubMed1978

Carcinoembryonic antigen test for recurrent colorectal carcinoma. Inadequacy for early detection.

Serum carcinoembryonic antigen (CEA) tests were performed on 36 patients with histologically proved locally recurrent or residual malignant disease after resection of colorectal carcinoma but with no clinical evidence of distant metastasis. Only nine patients (25%) had abnormal CEA levels of greater than 5 ng/ml despite the fact that most patients had had symptoms of recurrence for several months. Among the nine of our patients, none had CEA values greater than 5 ng/ml, and only three had levels greater than 2.5 ng/ml (3.4, 3.8, and 4.7 ng/ml). The CEA assay is not a sensitive test for early detection of recurrence of colorectal carcinoma.

Adenocarcinoma↗
PubMed1978

Pancreatic, gallbladder, and intestinal responses to intraluminal magnesium salts in man.

To assess the effects of magnesium chloride or magnesium sulfate on the release of cholecystokinin from the duodenum, outputs of trypsin and bilirubin were quantified during perfusion of the duodenum with isotonic solutions of these salts. Net intestinal water transport was also quantified. The results suggest that magnesium ion in the duodenum is a relatively weak stimulus to the pancreas and gallbladder, an action not augmented by the concomitant presence of the sulfate ion. As determined by this human bioassay method, magnesium is a weak stimulant to cholecystokinin release. Furthermore, magnesium chloride inhibits net jejunal water absorption and magnesium sulfate is even more potent, promoting net water secretion, effects which cannot be entirely attributed to cholecystokinin release.

Adult↗
PubMed1978

Comparison of the effects of pentagastrin and meal-stimulated gastrin on plasma calcitonin in normal man.

We compared the effects of exogenous pentagastrin and meal-stimulated gastrin on plasma immunoreactive calcitonin (iCT) in various studies of 13 normal adult men. Bolus intravenous injection of pentagastrin (0.5 microgram/kg) produced increases of iCT in 8 of 9 men. There was a linearly increasing response of iCT concentrations to increasing doses of pentagastrin (0.0625, 0.125, 0.25, and 0.5 microgram/kg) and to achieved serum immunoreactive pentagastrin concentrations (r = 0.72, P less than 0.01). To determine the effects of endogenous gastrin upon peripheral iCT concentrations, we measured serum immunoreactive gastrin (iG) and plasma iCT in four men at frequent intervals for 240 min after ingestion of low- (100 mg) and high- (400 mg) calcium meals. Serum iG increased in all subjects, with a peak at approximately 30 min. However, plasma iCT levels were unchanged from basal throughout the study. The increase of pentagastrin (0.3 pmol/ml) which caused a barely detectable increase of iCT was five- to tenfold greater than the mean maximal increases of gastrin after low- and high-calcium meals (0.04 and 0.06 pmol/ml, respectively). These results suggest that increases of plasma iCT concentrations after administration of pentagastrin in man reflect pharmacologic phenomena and that postprandial gastrin secretion may be insufficient to affect peripheral iCT concentrations.

Adult↗
PubMed1978

Combined deficiency of glucose-6-phosphatase and fructose-1, 6-diphosphatase. Studies of glucagon secretion and fuel utilization.

An adult woman with hypoglycemia, hyperlactatemia, hyperuricemia, hypertriglyceridemia, hyperketonemia and inability to make new glucose from galactose, fructose, glycerol and alanine was found to have no hepatic glucose-6-phosphatase and deficient fructose-1,6-diphosphatase. Nonautonomous hyperglucagonemia was demonstrated and shown to contribute to the hyperlactatemia and hyperketonemia. A paradoxic hyperlactatemic response to glucose and galactose was observed. Studies of substrate utilization showed prompt adaptation to changes in dietary supply of energy which probably accounted for her never having experienced symptoms of hypoglycemia.

Adult↗
PubMed1978

Oral prednisone for chronic active liver disease: dose responses and bioavailability studies.

Serum concentrations of prednisolone were measured by radioimmunoassay after the administration of prednisone (10, 20, or 30 mg) by mouth to five healthy volunteers, five patients with severe chronic active liver disease (CALD), and five patients with CALD in remission induced by prednisone. Only minor differences were found between the groups and bioavailability was linearly related to the dose of prednisone (r = 0.993). After prednisone (10 mg) was given by mouth and by vein to similar groups of volunteers and 11 additional patients with CALD, bioavailability of oral prednisone approximated 100% of the intravenous dose and no differences were found in the pharmacokinetics of prednisolone. We conclude that prednisone is effectively absorbed and converted to prednisolone in health and CALD and find no pharmacological evidence that either drug would be superior to the other for treating CALD.

Administration, Oral↗
PubMed1978

Postprandial duodenal function in man.

Duodenal function was studied in 11 healthy volunteers after intragastric instillation of a mixed semi-elemental meal. The duodenum accepted chyme of varying pH, osmolality, and nutrient concentration; and, as a result of biliary, pancreatic, and enteric secretion as well as absorption, it delivered chyme with nearly constant pH, osmolality, and nutrient concentration to the jejunum. The flow rate and nutrient load of jejunal chyme varied. The duodenum absorbed more carbohydrate than lipid and less protein, taking up each nutrient at a constant rate during most of the postprandial period. The percentage of nutrient load absorbed was greatest in the late postprandial period, when flow rate, nutrient load, and concentrations were low.

Adult↗
PubMed1978

Electrical and mechanical effects of molecular variants of CCK on antral smooth muscle.

Intracellular microelectrode and standard organ bath techniques were used to study in vitro the effects of three molecular forms of the peptide cholecystokinin on the electrical and mechanical activities of canine antral circular muscle. Three forms were studied: the carboxyl-terminal octapeptide of cholecystokinin (CCK-OP), the molecule containing 33 amino acid residues (CCK33), and the peptide termed "cholecystokinin variant" that contains 39 amino acids (CCK39). All three forms increased the force and frequency of spontaneous contractions. They also increased the frequency and the amplitude and duration of the plateau of the gastric action potential. Atropine did not block any of these effects, suggesting that the action of these peptides was largely due to a direct action on the smooth muscle. Complete dose-response curves were determined for the effect of these peptides on the force and frequency of contraction for muscle strips and for the effect on amplitude of the plateau and frequency of the action potential for single cells. CCK39 and CCK-OP had similar potencies and both forms were more potent than CCK33.

Action Potentials↗