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Biomedical subjects

J C Thompson

Publications and source records attributed to J C Thompson.

At least 361 records · Page 20Linked to original sources
PubMed1984

Effect of alcohol on the release of cholecystokinin and pancreatic enzyme secretion.

Ethanol is often implicated in the pathogenesis of acute pancreatitis, but the pathophysiologic processes of alcohol-induced acute pancreatitis remains poorly understood. We found that ingestion of alcohol by healthy volunteers did not stimulate release of cholecystokinin, which is the chief hormonal stimulant of pancreatic enzyme secretion, nor did it significantly alter fasting levels of pancreatic polypeptide, a hormonal inhibitor of pancreatic enzyme secretion. In conscious dogs prepared with chronic pancreatic fistulas, direct intraduodenal instillation of ethanol significantly reduced pancreatic protein output, and this reduction corresponded to a decline in plasma concentrations of cholecystokinin that was similar in the percentage of diminution and in duration. These data suggest that, in patients who do not have chronic pancreatitis, alcohol does not induce acute pancreatitis, either by stimulating cholecystokinin release or by stimulating enzyme secretion directly.

Adult↗
PubMed1984

Radioimmunoassay of pancreatic polypeptide in mammalian and submammalian vertebrates using a carboxyl-terminal hexapeptide antiserum.

Pancreatic polypeptide (PP) immunoreactivity in acid-ethanol extracts of the pancreas of representative species of mammals, birds, reptiles, amphibians, and fish was studied by a radioimmunoassay (RIA) that utilizes an antiserum which cross-reacts exclusively with the COOH-terminal hexapeptide of PP (CTPP). PP immunoreactivity in acid-ethanol extracts of rat nonpancreas tissues (stomach, duodenum, skeletal muscle, brain) was also examined. Significant concentrations of PP immunoreactivity were detected in the pancreatic extracts of all species, except fish. Appreciable quantities of PP immunoreactivity were also found in the stomach and duodenum of rats. In all cases, tissue extracts showed parallelism with reference PP (bovine) in the RIA. Gel chromatography (Sephadex G-50sf) of tissue extracts (rat, turtle) demonstrated a major peak of PP immunoreactivity, which eluted in the region of the reference PP. Salamander PP immunoreactivity eluted after bovine PP. In addition, the CTPP RIA can be applied to measure plasma levels of PP in rats, dogs, and humans. By using this PP RIA, we observed that plasma PP levels increase significantly in dogs (P less than 0.05) after intravenous administration of neurotensin. In rats, administration of intravenous bombesin resulted in a significant elevation of plasma PP.

Animals↗
PubMed1984

Insulinotropic and gastrin-releasing action of gastrin-releasing peptide (GRP).

The effect of intravenous administration of gastrin-releasing peptide ( GRP ) on serum gastrin and insulin levels was studied in ad libitum fed and 24-h fasted rats. Administration of GRP (55 micrograms/kg body weight) caused a significant (P less than 0.05) elevation in serum gastrin levels at 10, 30, 60, and 120 min in the rats fed ad libitum, whereas in the fasted rats, gastrin levels rose significantly only at 10 min. GRP did not cause insulin release in fasted rats, but in the fed rats, it led to a significant elevation in serum insulin levels at 10 and 30 min, in comparison to controls. GRP appears to have an insulinotropic action in addition to a gastrin-releasing effect.

Animals↗
PubMed1984

Experience with the routine use of an abbreviated crossmatch.

Three years' experience with the routine use of an abbreviated crossmatch procedure is reported. If a patient had no known history of and/or no currently demonstrable unexpected antibodies, ABO and Rh type specific blood was crossmatched at the time of need by using an immediate spin saline abbreviated crossmatch. Once blood was issued, both a 37 degrees C incubation and an antiglobulin crossmatch were done using the same tube employed for the abbreviated crossmatch. This served as a check that clinically significant antibodies were not overlooked. None of the 19,818 patients transfused following an abbreviated crossmatch suffered an acute hemolytic transfusion reaction as a result of this strategy; however, two patients may have manifested asymptomatic hemolysis. This approach to compatibility testing might be appealing to hospitals faced with fiscal limitations and new regulations affecting hospital reimbursement.

Adult↗
PubMed1984

Physiologic role of cholecystokinin in the intestinal phase of pancreatic polypeptide release.

Release of pancreatic polypeptide (PP) after a meal is biphasic, with an early transient peak believed to be under cholinergic control, and a secondary, prolonged intestinal phase thought to be mediated by hormones. Endogenous release of PP was stimulated by intraduodenal oleate (6.8 mmol/hr) or by intravenous administration of pure cholecystokinin-33 (CCK-33, 0.1 micrograms/kg/hr) in five dogs. Radioimmunoassay measurements of plasma concentrations of PP and CCK-33 were compared by linear regression analysis before and after vagotomy. Correlations between plasma concentrations of PP and CCK-33 before vagotomy (r = 0.83 [oleate], r = 0.97 [IV-CCK-33]) and after vagotomy (r = 0.92 [oleate], r = 0.92 [IV-CCK-33]) were highly significant. Changes in plasma concentrations of PP relative to a particular increment in plasma CCK-33 (before vagotomy) were similar, whether stimulated by oleate or by exogenous CCK-33. After vagotomy, less PP was released relative to a change in plasma CCK-33 (stimulated by oleate or by exogenous CCK-33), but the PP response relative to a change in plasma CCK-33 induced by the two stimuli remained remarkably similar. These results provide evidence that the intestinal phase of physiologic release of PP is mediated to a large extent through release of CCK.

Animals↗
PubMed1984

Intracerebroventricular administration of cholecystokinin-8 elevates plasma pancreatic polypeptide levels in awake dogs.

The effect of intracerebroventricular (ICV) administration of cholecystokinin-8 (CCK-8) (0.5, 1.0, 2.0, 4.0 micrograms) on plasma levels of pancreatic polypeptide (PP) was studied in conscious dogs. ICV administration of CCK-8 (1.0, 2.0, 4.0 micrograms) produced a rapid and transient elevation in plasma concentrations of PP. Peripheral muscarinic receptor blockade with atropine or truncal vagotomy abolished PP secretion induced by ICV CCK-8. Pretreatment with ICV atropine also prevented the elevation in plasma PP induced by CCK-8. Plasma levels of CCK-33/39, CCK-8, and gastrin were not affected by ICV CCK-8. Our results indicate that central administration of CCK-8 selectively elevated plasma PP concentration. Since the effect of CCK-8 on plasma PP was abolished by central and peripheral atropine pretreatment, as well as by vagotomy, central and peripheral vagal cholinergic mechanisms appear to participate in release of PP that is induced by CCK-8 given by ICV injection.

Animals↗
PubMed1984

Release of cholecystokinin in response to food and intraduodenal fat in pigs, dogs and man.

The present study was done to compare endogenous cholecystokinin-33 release in response to physiologic stimuli (meal, fat) in pigs, dogs and man. Plasma levels of cholecystokinin-33 were monitored using a radioimmunoassay for cholecystokinin which detects only cholecystokinin-33 and cholecystokinin-39. Ingestion of a meal caused release of cholecystokinin-33 within five, 20 and 120 minutes in man, pigs and dogs, respectively. Intraduodenal administration of corn oil resulted in a significant release of cholecystokinin-33 within 20 minutes in dogs, pigs and man.

Adult↗
PubMed1984

Role of neurotensin in pancreatic secretion.

The objective of this study was to examine the effect of neurotensin (NT) on pancreatic exocrine secretion in awake dogs (n = 5) with chronic gastric and pancreatic fistulas. Intravenous (IV) infusion of NT (1 microgram/kg/hr) alone significantly stimulated pancreatic secretion of protein and bicarbonate without causing release of secretin or cholecystokinin-33 (CCK-33). IV NT potentiated the secretory response of pancreatic bicarbonate to the intraduodenal (ID) infusion of HCl alone and to ID infusions of the amino acids, phenylalanine and tryptophan (AA) alone, as well as to an ID mixture of AA plus HCl. IV NT acted in an additive manner with ID AA, ID HCl, or ID AA plus HCl in the stimulation of pancreatic protein output. The addition of IV NT to each luminal secretagogue (ID AA, ID HCl, or ID AA plus HCl) failed to elevate plasma concentrations of CCK-33 or secretin over those observed during ID infusion of each secretagogue alone. ID corn oil (Lipomul) stimulated the simultaneous release of CCK-33, NT, and secretin significantly; IV infusion of NT (0.5 microgram/kg/hr) resulted in plasma NT levels that were similar to levels observed after ID Lipomul. These studies provide evidence that endogenous NT, CCK, and secretin may interact in the physiologic regulation of pancreatic exocrine secretion.

Amino Acids↗
PubMed1984

Plasma concentrations of cholecystokinin in patients with duodenal ulcer disease.

Cholecystokinin (CCK) is structurally similar to gastrin and is known to competitively inhibit the action of gastrin on the parietal cell, but little information has been accumulated about circulating levels of CCK in patients with duodenal ulcer (DU). In a group of 18 healthy volunteers (controls) and 22 DU patients (13 with active DU, nine with inactive DU), we stimulated endogenous release of CCK with oral administration of Lipomul corn oil. Plasma concentrations of CCK were measured by radioimmunoassay; ultrasonographic measurements of gallbladder volume were used as a biologic correlate for CCK in control patients and in patients with active DU. No significant difference was found in fasting plasma concentrations of CCK between controls (107 +/- 8 pg/ml) and DU patients (123 +/- 15 pg/ml), or in their total integrated release of CCK during the first hour after Lipomul ingestion (3.7 +/- 0.7 ng-min/ml in controls, 2.8 +/- 0.4 ng-min/ml in DU patients). Furthermore, no significant difference was found in integrated release of CCK between patients with active DU (2.9 +/- 0.6 ng-min/ml) and those with inactive DU (2.8 +/- 0.6 ng-min/ml). Gallbladder volume was highly correlated with plasma concentrations of CCK in controls (r = -0.91) and in active DU patients (r = -0.98). Patients with active DU had significantly smaller volumes of their resting gallbladders, they emptied less of their resting gallbladder contents in response to fat, and they showed diminished sensitivity to endogenously released CCK compared to controls. In six patients with active DU who underwent truncal vagotomy and drainage, integrated release of CCK increased significantly, from 1.9 +/- 0.6 ng-min/ml before vagotomy to 9.3 +/- 3.0 ng-min/ml after vagotomy. We found no evidence to suggest that abnormalities in release of CCK contributes to the development of duodenal ulcers. We speculate, however, that the increased release of endogenous CCK after truncal vagotomy may possibly play an etiologic role in the syndrome of postvagotomy diarrhea.

Adult↗
PubMed1984

Comparison of cholecystokinin release and gallbladder emptying in men and in women at estrogen and progesterone phases of the menstrual cycle.

Why are gallstones more common in women than in men? To investigate this, we measured gallbladder emptying (by ultrasonography) and release of endogenous cholecystokinin (CCK) (by specific radioimmunoassay) in eight men and nine women in response to ingestion of corn oil (1 gm/kg). Each woman was studied on the fourteenth and twenty-first day of her menstrual cycle, estimated to be the estrogen (women [E] ) and progesterone (women [P] ) peaks, respectively. Fasting plasma concentrations of CCK were significantly higher in women (E) (135 +/- 7 pg/ml) than in men (99 +/- 13 pg/ml) but not significantly higher than in women (P) (113 +/- 11 pg/ml). The peak increase in CCK concentration over basal concentration and the integrated release of CCK were not significantly different from one group to another. Men had a larger fasting gallbladder volume (GBV) (21.4 +/- 3.2 ml) than did women (E) (12.4 +/- 2.1 ml) and women (P) (14.2 +/- 2.1 ml) and emptied more GBV in response to fat than did the women. The residual GBV and fractional emptying after ingestion of corn oil were not different among the three groups. Measurements of plasma CCK and GBV during the contraction phase were highly correlated in all groups. It appears, from these data, that the increased prevalence of gallstones in women relative to men cannot be explained on the basis of significant differences either in release of CCK or in gallbladder motility. Linear regression lines that were developed indicated that the mean change in GBV relative to a given change in plasma CCK was significantly higher in men than in women. Differences between men and women in this hormonal-motility relationship may contribute to the incidence of gallstones in premenopausal women.

Adult↗
PubMed1983

Electrical injuries in children.

Electrical injuries in children continue to account for substantial morbidity and mortality. This review describes the responsible pathogenetic mechanisms and five separate types of injury. Multisystem complications are discussed as well as current concepts of patient management. We emphasize the importance of prevention and include a pediatrician's "reminder" list for parent education.

Burns, Electric↗
PubMed1983

Biologic and radioimmunologic activity of cholecystokinin in regions of mammalian brains.

The distribution and heterogeneity of cholecystokinin (CCK) in different regions of the central nervous system (CNS) of 12 adult rats and six cows was determined by means of specific radioimmunoassays. In addition, the biologic activity of immunoreactive material was evaluated in a bioassay that used a rabbit gallbladder-strip preparation. High amounts of immunochemically detectable CCK-8 (20.2 +/- 1.5 pmol/g) and CCK-33 (33.7 +/- 3.3 pmol/g) and of biologically active CCK were found in the telencephalon, although concentrations decreased progressively from the rostral to the caudal portions of the brain. The distribution and biologic activity of CCK was similar in rat and cow brain. Ratios of biologic to immunologic activity ranged from 1.0 to 8,0 and were higher for CCK-8 than for CCK-33. The results indicate that (1) CCK-8 and CCK-33 immunoreactivity are widely distributed throughout the CNS in a unique and differential manner; (2) CCK is biologically active in all the regions of the brain, with a pattern of distribution similar to that found with radioimmunoassay; (3) measurable bioactivity was equal to or greater than measurable immunoreactivity in all areas of the brain in rat and cow; and (4) CCK is present in tissues without significant species differences between rat and cow.

Animals↗
PubMed1983

Correlation between gallbladder size and release of cholecystokinin after oral magnesium sulfate in man.

In order to determine the effect of oral magnesium sulfate on gallbladder contraction and release of cholecystokinin (CCK) in man, magnesium sulfate (25 g in 100 ml distilled water) was given by mouth to five fasting adult male volunteers. Plasma samples were collected for measurement of CCK by a specific radioimmunoassay. Gallbladder volumes were determined from sonograms obtained from a phased-array real-time ultrasound scanner. Basal concentrations of CCK (82.2 +/- 10.1 pg/ml) increased significantly at 20 minutes after oral magnesium sulfate (113.8 +/- 7.1 pg/ml), and reached a maximal value at 50 minutes (150.0 +/- 42.0 pg/ml). The mean basal volume of the gallbladder was 30.8 +/- 5.3 cm(3) and maximum reduction of gallbladder volume (to one third of original) was achieved at 50 minutes after ingestion of magnesium sulfate. Linear regression analysis showed a close correlation (r = -0.9337) between plasma concentrations of CCK and gallbladder size in response to magnesium sulfate. Oral magnesium sulfate also caused a significant increase in serum gastrin (from basal of 51.4 +/- 9.9 pg/ml to 69.8 +/- 15.5 pg/ml at 5 min); there was no significant correlation between gastrin release and gallbladder contraction. This study provides direct evidence that the mechanism of magnesium sulfate-stimulated gallbladder contraction occurs through the release of CCK, and shows a close correlation between CCK release and contraction of the gallbladder.

Adult↗
PubMed1983

The role of surgery in the Zollinger-Ellison syndrome.

When the Zollinger-Ellison syndrome was first identified, total gastrectomy was proposed as the most effective treatment for the secretory manifestations of the syndrome. Recently, however, great enthusiasm has developed for medical treatment by means of H2-receptor antagonists. The authors have cared for 27 patients with the Zollinger-Ellison syndrome at The University of Texas Medical Branch in the past 12 years and have been pleased with the results of total gastrectomy, which was performed in 23 of the 27 patients (one patient refused operation and three patients had lesser gastric operations). Twenty-three patients underwent total gastrectomy with Roux-en-Y esophagojejunostomy. There were no operative deaths. Primary tumors were found in 17 patients, seven of whom also had metastatic tumors. No tumors were found in nine patients. Nine patients are dead; the actuarial survival rate for all patients was 75% at 5 years and 52% at 10 years. Eleven of the 27 patients had the multiple endocrine neoplasia I syndrome. Of the 18 survivors, only three have normal serum gastrin levels, and all three had extrapancreatic gastrinomas, one in peripancreatic lymph nodes, one in the liver, and one in a cystic tumor attached to the stomach. Nutritional results were good to excellent, with a mean postoperative weight loss of 14.7% (mean follow-up period was 45 months). The authors conclude that treatment of the hypersecretory problems of the Zollinger-Ellison syndrome by total gastrectomy is safe and dependable. Results compare well with those of long-term medical management, whose success is dependent upon serial favorable responses to a lifetime of repeated challenges.

Adolescent↗