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Biomedical subjects

J B Jansen

Publications and source records attributed to J B Jansen.

At least 181 records · Page 10Linked to original sources
PubMed1991

Physiological role of cholecystokinin on postprandial insulin secretion and gastric meal emptying in man. Studies with the cholecystokinin receptor antagonist loxiglumide.

Cholecystokinin was previously proposed to play an important role in the regulation of postprandial insulin secretion either indirectly, by inhibiting gastric meal emptying, or directly, by acting as an incretin promoting the release of insulin. The aim of this investigation was therefore to clarify the role of endogenous cholecystokinin in the regulation of insulin release and gastric emptying applying the highly potent and specific cholecystokinin receptor antagonist loxiglumide. Five healthy volunteers were examined after an overnight fast. Gastric meal emptying was measured by the double indicator technique using a multiple lumen tube in the duodenum and 99mTc-diethylenetriamine pentaacetate as a meal marker and polyethylene glycol 4000 as a duodenal perfusion marker. Postprandial insulin, C-peptide, cholecystokinin and glucose levels were measured after ingestion of two isocaloric meals of a) Ensure (containing fat, protein and glucose), and b) a pure glucose meal (1.11 mol/l). The meals were given either with an intravenous infusion of loxiglumide (22 mumol.kg-1.h-1) or placebo. The infusion of loxiglumide markedly accelerated the gastric emptying of the mixed meal (area under curve, 5576 +/- 352 min vs 3498 +/- 109 min; p less than 0.001) and the pure glucose meal (area under curve 5662 +/- 537 min vs 3551 +/- 534 min; p less than 0.05). Simultaneously, loxiglumide induced a more rapid rise in postprandial insulin levels after both meals resulting in significantly higher (p less than 0.05) insulin levels during the first postprandial hour, but similar insulin levels in the second postprandial hour. Accordingly, we found a close correlation between meal emptying and insulin release (r = 0.748, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Role of cholecystokinin in the regulation of gastric emptying and pancreatic enzyme secretion in humans. Studies with the cholecystokinin-receptor antagonist loxiglumide.

The role of cholecystokinin (CCK) in the regulation of gastric emptying and pancreatic enzyme secretion was evaluated by infusing the CCK-receptor antagonist loxiglumide. Gastric emptying rates and pancreatic secretory outputs were measured in five healthy volunteers by the double-indicator perfusion technique using a multiple-lumen tube in the duodenum. Placebo or loxiglumide (22 mumol.kg-1.h-1) was infused throughout each experiment. Five hundred-milliliter liquid intragastric meals of (a) fat, protein, and glucose (Ensure; Abbott, Chicago, IL); (b) glucose, 20 g/dL; and (c) guar gum, 1.1 g/dL, were given in random order. In addition, the effect of a physiologic CCK-8 dose (20 pmol.kg-1.h-1) after an intragastric 500-mL saline meal (0.154 mol/L) was tested. Intravenous CCK-8 induced a marked retardation of the gastric emptying rate of the saline solution (P less than 0.05) while stimulating pancreatic secretory outputs; both effects were completely abolished by the infusion of loxiglumide. Loxiglumide markedly accelerated the gastric emptying rates (by approximately 40%) and simultaneously diminished lipase (by approximately 75%) and trypsin (by approximately 50%) outputs of both the mixed meal (P less than 0.01) and the pure glucose meal (P less than 0.05). Additional experiments using gamma camera scintigraphy confirmed the accelerating effect of loxiglumide on gastric emptying of the mixed meal (P less than 0.01). The gastric emptying rate of the guar meal, which did not release CCK, was not influenced by the infusion of loxiglumide. Loxiglumide distinctly augmented plasma CCK levels after the mixed (2.6 times) and the pure glucose (2.1 times) meals while markedly reducing (approximately 76%) pancreatic polypeptide release (P less than 0.02). It is concluded that endogeneous CCK exerts a major role in the regulation of both gastric liquid emptying and pancreatic secretion in humans.

Adult↗
PubMed1991

Natural killer cell activity in patients with neuroendocrine tumours of the gastrointestinal tract; relation with circulating gastrointestinal hormones.

We have evaluated the peripheral blood natural killer (NK) cell activity and the in vitro effect of recombinant gamma-interferon (r gamma-IFN) on NK cell activity in 23 patients with a neuroendocrine tumour of the pancreas, small intestine or liver, and 23 healthy controls. Patients with a gastrinoma showed a NK cell activity which was not different from that of the control group, whereas patients with another type of neuroendocrine tumour had a decreased NK cell activity compared to the controls (p less than 0.05) and the gastrinoma patients (p less than 0.02). The impaired NK cell activity in these patients was as such not related to the presence of liver metastasis or performance status of the patients. r gamma-IFN significantly stimulated the NK cell activity in patients and controls. However, the cytotoxic response of the patients with a hormone production other than gastrin remained lower than in the two other groups. Follow-up studies in 8 patients showed NK cell activities not to vary with stable disease, to decrease with progressive disease, and to increase with regression of disease. In conclusion, NK cell activity is suppressed in patients with neuroendocrine tumours that produce hormones other than gastrin. This impairment is not related to the presence of metastasis but seems to be related to the course of the disease.

Adult↗
PubMed1991

Increased plasma cholecystokinin levels and small gall bladders in adult patients with cystic fibrosis.

1. In patients with cystic fibrosis, abnormalities in plasma cholecystokinin level and gall-bladder emptying may contribute to the development of maldigestion and gall-stones. 2. Therefore, we have measured plasma cholecystokinin levels and gall-bladder volumes before and after ingestion of a standard breakfast in eight adult patients with cystic fibrosis and in eight normal control subjects. 3. In the patients with cystic fibrosis basal (2.8 +/- 0.4 pmol/l; P less than 0.05, t-test) and maximum post-prandial (5.7 +/- 0.5 pmol/l; P less than 0.05, t-test) plasma cholecystokinin levels were significantly higher than those in the control subjects (1.9 +/- 0.1 pmol/l, and 4.5 +/- 0.2 pmol/l, respectively). On the other hand, integrated plasma cholecystokinin secretion in response to the meal was similar (t-test, P = 0.4 versus control subjects). The increased plasma cholecystokinin levels in the patients with cystic fibrosis were accompanied by reduced gallbladder volumes in both the basal (7.8 +/- 2.1 cm3 versus 20.9 +/- 2.3 cm3 in control subjects; P less than 0.005, t-test) and the post-prandial state (2.2 +/- 1.0 cm3 versus 4.8 +/- 0.8 cm3 in control subjects; P = 0.06, t-test). Gall-bladder emptying in the patients with cystic fibrosis was well preserved (70 +/- 7% versus 78 +/- 9% in control subjects; P = 0.4, t-test). 4. In comparison with normal control subjects, patients with cystic fibrosis have an increased basal plasma cholecystokinin level and a reduced gall-bladder volume, whereas post-prandial gall-bladder emptying and plasma cholecystokinin secretion are not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Effect of the cholecystokinin-receptor antagonist lorglumide on pancreatic enzyme secretion stimulated by bombesin, food, and caerulein, giving similar plasma cholecystokinin concentrations in the dog.

This study was undertaken to determine the role of cholecystokinin in pancreatic enzyme secretion stimulated by bombesin and a meal by (a) comparing the pancreatic enzyme output during bombesin infusion and after a meal to output during caerulein infusion and (b) comparing the inhibitory effect of the cholecystokinin-receptor antagonist lorglumide (CR-1409) on enzyme output in response to bombesin and food with the response to caerulein. Bombesin (90 pmol/kg per h) and caerulein (30 pmol/kg per h) were infused into seven dogs in doses giving similar plasma cholecystokinin peak increments as a meal (mean (SEM) 6.8 (0.8), 6.3 (1.2), and 5.7 (0.8) pM, respectively), together with either saline or 2 mg/kg per h of lorglumide. A background infusion of synthetic secretin 20.5 pmol/kg per h was given in each experiment. In addition, gastric acid secretion was determined in the experiments with bombesin and caerulein infusion. Pancreatic protein responses to bombesin (1231 (247) mg/h) and food (1430 (220) mg/h) were similar to the responses to caerulein (1249 (201) mg/h). Lorglumide inhibited pancreatic protein output during stimulation with bombesin by 60%, after the meal by 45%, and during caerulein infusion by 68%. Pancreatic bicarbonate output by bombesin, caerulein, and food was inhibited by lorglumide by 28%, 40%, and 38%, respectively. In contrast, lorglumide significantly increased gastric acid secretion from 1.12 to 7.98 mmol/h during bombesin infusion and from 0.52 to 7.62 mmol/h during caerulein infusion. In conclusion, cholecystokinin plays an important part in the stimulation of pancreatic enzyme secretion by bombesin and a meal in conscious dogs and it is involved in the regulation of gastric acid during stimulation by infusions of caerulein and bombesin.

Animals↗
PubMed1991

Weekend treatment with 20 and 40 mg omeprazole: effect on intragastric pH, fasting and postprandial serum gastrin, and serum pepsinogens.

Weekend treatment with 20 mg omeprazole reduces ulcer relapse rates but the results may improve with a higher dose regimen. We have evaluated three day weekend treatment with 20 and 40 mg doses of omeprazole in eight healthy subjects in a double blind crossover study. Twenty four hour ambulatory intragastric pH and basal and meal stimulated serum gastrin and serum pepsinogens A and C values were studied. The investigations began on the Friday before the third weekend course of omeprazole and were repeated on alternate days, except Sundays, for two weeks. When compared with values before the study, median 24 hour intragastric pH and basal and meal stimulated gastrin concentrations were significantly (p less than 0.01-0.05), but transiently, raised with both doses of omeprazole. Basal pepsinogen A and C values were significantly (p less than 0.01) increased on all study days, but did not return to their pre-study values before the next weekend dose, except for pepsinogen C in subjects treated with 20 mg omeprazole. A dose dependent effect was found for all parameters studied (p less than 0.05). In conclusion, weekend treatment with 20 and 40 mg omeprazole produces pronounced and dose dependent increases in intragastric pH, basal and meal stimulated serum gastrin, and basal serum pepsinogen A and C without inducing prolonged hypoacidity or hypergastrinaemia. Weekend treatment with 40 mg omeprazole merits further study in the prevention of peptic ulcer relapse.

Adult↗
PubMed1991

Repeated intravenous bolus injections of omeprazole: effects on 24-hour intragastric pH, serum gastrin, and serum pepsinogen A and C.

We determined the effect of four times daily dosing with intravenous omeprazole on 24-h intragastric acidity, serum gastrin, and serum pepsinogen A and C in 10 fasting subjects (median age, 23.5 years). Two dose regimens (80-20-20-20 mg and 80-40-40-40 mg) were compared in a randomized placebo-controlled crossover study. Intragastric pH was continuously monitored during 24 h, using combined glass electrodes, and blood samples were taken every 6 h. Repeated boluses of omeprazole every 6 h significantly increased (p less than 0.01) the median 24-h intragastric pH compared with placebo (median pH, 3.7 (140 mg/day), 4.3 (200 mg/day), and 1.4 (placebo)) but failed to continuously raise pH levels above 4.0 in 8 (140 mg/day) or 9 (200 mg/day) of 10 subjects. No advantage of the 200-mg dose over the 140-mg dose was demonstrated. A cumulative effect of intravenous omeprazole was shown after repeated boluses but also a marked interindividual variation in response, which was correlated with the omeprazole area under the plasma concentration time curve. A significant elevation of serum gastrin coincided with the increased pH levels, which was followed after 12-18 h by a significant increase of both serum pepsinogens.

Adult↗
PubMed1991

Gallbladder sensitivity to cholecystokinin in coeliac disease. Correlation of gallbladder contraction with plasma cholecystokinin-like immunoreactivity during infusion of cerulein.

The present study was undertaken to determine whether alterations in the gallbladder sensitivity to cholecystokinin (CCK), apart from a reduced endogenous CCK secretion, contribute to the abnormally decreased postprandial gallbladder contraction in patients with coeliac disease. Gallbladder emptying, measured by cholescintigraphy, and plasma CCK levels, measured by radioimmunoassay, were studied during infusion of graded doses of the CCK analog cerulein in six coeliac patients with subtotal villous atrophy, six coeliac patients on a gluten-free diet with normal villous architecture, and nine control subjects. Both in the patients and in the controls infusion of stepwise increasing doses of cerulein, in the range of 1-16 ng.kg-1.h-1, induced dose-related changes in plasma CCK-like immunoreactivity (CCK-LI) (r = 0.99; p less than 0.001) and gallbladder emptying (r greater than 0.97; p less than 0.01-p less than 0.001). Plasma CCK-LI and gallbladder responses were not significantly different among untreated coeliac patients, treated coeliac patients, and controls. Gallbladder sensitivity to cerulein in untreated and treated coeliac patients was not significantly different from that in controls. It is concluded that the abnormally decreased gallbladder contraction in coeliac patients is the result of a reduced endogenous CCK secretion and not of a lack of end-organ responsiveness to CCK.

Celiac Disease↗
PubMed1991

Modulatory effects of VIP and related peptides from the gastrointestinal tract on cell mediated cytotoxicity against tumour cells in vitro.

In the present study the effect of vasoactive intestinal peptide (VIP), peptide histidine-methionine (PHM), and secretin on spontaneous cell mediated cytotoxicity of peripheral blood mononuclear cells against tumour target cells was evaluated. VIP stimulated cytotoxicity against CaCo-2 human colon cancer cells, whereas less effect was seen against K-562 erythroleukemia cells. Depletion of CD16+ natural killer cells almost completely abolished cytotoxicity and subsequent VIP incubation did not change residual activity. In contrast to PHM, which hardly influenced cytotoxicity, secretin was found to be more effective especially against K-562 target cells. These observations suggest a modulating role for the neuropeptide VIP in the cellular immune response against tumour cells, especially from the colon, resulting in increased activity of CD16+ natural killer cells. Secretin, seems to be less potent in modulating cellular cytotoxicity. These findings support the concept that gastrointestinal peptides can play a role in the regulation of cellular cytotoxicity against tumor cells.

Colonic Neoplasms↗
PubMed1991

Severely impaired postprandial gallbladder emptying despite unchanged cholecystokinin release in the early phase of biliary colic.

In the present article we report transitory severely impaired postprandial gallbladder emptying preceding biliary colic in a cholesterol gallstone patient. Gallbladder emptying 1 wk before and 3 wk after the biliary colic was normal. Treatment with ursodeoxycholic acid led to increased fasting gallbladder volumes, but the postprandial residual volume did not change. Postprandial cholecystokinin release appeared not to change during ursodeoxycholic acid treatment or during biliary colic.

Biliary Tract Diseases↗
PubMed1990

Cholecystokinin and gastrointestinal cancer.

The gut hormone cholecystokinin exerts various actions on the gastrointestinal tract, including the regulation of growth. The hormone has been reported to induce hypertrophy and hyperplasia of the pancreas and to enhance chemically-induced pancreatic carcinogenesis in animals. Stimulation of endogenous cholecystokinin secretion through the induction of deficiency of intraintestinal proteases and bile salts by trypsin-inhibiting nutrients, bile salt-binding drugs or surgical intervention is also capable of stimulating growth and tumour development in the rat. In man, factors suggested to increase the risk of pancreatic cancer, such as a high-fat and high-protein diet or gastrectomy, are known to stimulate plasma cholecystokinin secretion. Receptors for cholecystokinin have been demonstrated on human pancreatic adenocarcinomas, and cholecystokinin has been demonstrated to enhance the growth of xenografted pancreatic cancer and to inhibit growth of gastric and bile duct cancer. The recently developed cholecystokinin-receptor antagonists inhibit not only pancreatic growth but also pancreatic carcinogenesis in animals. These new drugs may be valuable new tools for inhibiting pancreatic cancer growth in humans.

Adenocarcinoma↗
PubMed1990

Role of cholecystokinin and the cholinergic system in intestinal stimulation of gallbladder contraction in man.

To determine the role of cholecystokinin and the cholinergic system in intestinal stimulation of gallbladder contraction, we studied the effects of atropine on plasma cholecystokinin and gallbladder contraction in six healthy volunteers (four men and two women aged 20 to 27 yr). Effects were noted after intraduodenal fat instillation and after dosage with exogenous cholecystokinin inducing plasma cholecystokinin concentrations similar to those after intraduodenal fat instillation. At regular intervals before and after administration of each stimulus, plasma cholecystokinin concentrations and gallbladder volumes were measured by radioimmunoassay and real-time ultrasonography, respectively. Intraduodenal infusion of 250 ml 20% Intralipid induced a peak plasma cholecystokinin increment of 10.2 +/- 1.6 pmol/L compared with 10.7 +/- 0.7 pmol/L during infusion of 1 Ivy dog unit per kilogram per hour of cholecystokinin. The increases in plasma cholecystokinin after fat and exogenous cholecystokinin administration were accompanied by similar decreases in gallbladder volume. Integrated gallbladder contraction after fat instillation was 3,939% +/- 288%.min compared with 3,301% +/- 359%.min during cholecystokinin infusion (NS). Atropine (0.015 mg/kg as bolus followed by 0.005 mg/kg/hr) did not change plasma cholecystokinin concentrations but induced similar inhibition of gallbladder contraction to 2,296% +/- 511%.min (p less than 0.05) after intraduodenal fat instillation and to 1,756% +/- 456%.min (p less than 0.05) during cholecystokinin infusion. We conclude that cholecystokinin is of major importance in intestinal stimulation of gallbladder contraction. Atropine inhibits the gallbladder response to intraduodenal fat. This inhibition is not due to a reduction in cholecystokinin secretion but to a diminished gallbladder response to cholecystokinin.

Adult↗
PubMed1990

Effect of loxiglumide (CR-1505) on bombesin- and meal-stimulated plasma cholecystokinin in man.

Cholecystokinin (CCK)-receptor antagonists have been reported to inhibit the effects of the hormone on the gastrointestinal tract. Their effect on plasma CCK levels in man has not been described. The present study in 5 normal subjects demonstrated that i.v. infusion of the potent, specific CCK-receptor antagonist loxiglumide (CR 1505) significantly augmented plasma CCK levels during infusion of bombesin (402 pM per 30 min) and after administration of a meal (1390 pM per 300 min) when compared to the bombesin- (192 pM per 30 min) and meal- (886 pM per 300 min) stimulated CCK responses during infusion of saline. The basal plasma CCK during saline infusion (0.1 pM per 40 min) was not significantly influenced by CR 1505 (-1.8 pM per 40 min). Thus, both enteral (meal) and parenteral (bombesin) stimulation of CCK secretion are augmented by CCK-receptor blockade.

Adult↗
PubMed1990

Effect of partial gastrectomy with Billroth II or Roux-en-Y anastomosis on postprandial and cholecystokinin-stimulated gallbladder contraction and secretion of cholecystokinin and pancreatic polypeptide.

This prospective study was undertaken to determine the effect of partial gastrectomy without vagotomy on postprandial gallbladder contraction and secretion of cholecystokinin (CCK) and pancreatic polypeptide (PP) in 22 peptic ulcer patients randomly assigned to either Billroth II (N = 11) or Roux-en-Y (N = 11) anastomosis. The patients were studied within two weeks before surgery and at six months postoperatively. After surgery basal gallbladder volumes were larger than preoperatively (P less than 0.02). Integrated postprandial gallbladder contraction was not significantly affected by gastrectomy, either in the patients with Billroth II anastomosis (2276 +/- 268 vs 1985 +/- 362%/60 min) or in those with Roux-en-Y anastomosis (2045 +/- 327 vs 2445 +/- 352%/60 min) when studied pre- and postoperatively, respectively. Similarly, integrated postprandial plasma CCK secretion was not significantly changed by either Billroth II gastrectomy (200 +/- 31 vs 166 +/- 21 pM/60 min) or Roux-en-Y gastrectomy (146 +/- 26 vs 147 +/- 12 pM/60 min). However, integrated postprandial PP secretion was significantly (P less than 0.05) lower after Billroth II gastrectomy (6.8 +/- 2.4 vs 2.2 +/- 1.0 nM/60 min), while the reduction in plasma PP after Roux-en-Y gastrectomy just failed to reach statistical significance (6.0 +/- 1.5 vs 3.4 +/- 0.9 nM/60 min). Similarly, the PP response, but not the gallbladder response, to an intravenous bolus injection of 1 IDU CCK/kg body weight was significantly decreased after gastrectomy independent of the type of anastomosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Roux-en-Y↗
PubMed1990

Role of cholecystokinin in bombesin- and meal-stimulated pancreatic polypeptide secretion in dogs.

This study was undertaken to delineate the role of cholecystokinin (CCK) in bombesin- and meal-stimulated pancreatic polypeptide (PP) secretion in seven conscious dogs by studying: (1) the stimulatory effect of similar plasma levels of CCK induced by a meal and infusions of bombesin and the synthetic CCK analog cerulein on plasma PP, and (2) the inhibition of PP secretion by the CCK-receptor antagonist CR-1409 during these three stimuli. The stimulation of PP secretion during bombesin (11.0 +/- 1.6 nM/hr) and after the meal (8.9 +/- 2.0 nM/hr) were significantly (P less than 0.05) greater than during infusion of the CCK analog cerulein (2.7 +/- 0.4 nM/hr). CR-1409 significantly inhibited the bombesin- and meal-stimulated PP secretion to 2.0 +/- 0.4 nM/hr (81%; P less than 0.05) and 3.1 +/- 1.2 nM/hr (47%; P less than 0.05), respectively, while the cerulein-stimulated PP release was almost abolished to 0.2 +/- 0.1 nM/hr (93%; P less than 0.05) by the drug. These findings point to an important role for CCK in the regulation of bombesin- and meal-stimulated PP secretion.

Animals↗
PubMed1990

Effect of intravenous omeprazole on intragastric pH during intravenous infusion of amino acids.

Intravenous amino acids stimulate gastric acid secretion by an unknown mechanism. In patients on parenteral nutrition, this amino acid-induced gastric acid secretion might contribute to the failure of H2-receptor antagonists to raise intragastric pH above 4.0, a level thought to be needed to prevent stress ulceration. Therefore we studied the effect of single and repeated doses of the H+/K(+)-ATPase blocker omeprazole on the intragastric pH during a 3-hr infusion of amino acids in 10 healthy volunteers; 5% glucose was used as a control infusion. Amino acids significantly decreased intragastric pH when compared to glucose infusion (P less than 0.05). After intravenous administration of 40 mg, 80 mg and 2 X 40 mg omeprazole, this amino acid-induced fall in pH was significantly inhibited (P less than 0.01). No advantage of the 80-mg dose over the 40-mg dose could be demonstrated. The repeated dose of 40 mg showed a tendency to higher pH values compared to the single-dose experiments, which reached significance in the amino acid experiments only (P less than 0.05). Neither during the infusion of amino acids nor the glucose infusion omeprazole was able to continuously raise intragastric pH above 4.0. In conclusion, this study shows that intravenous omeprazole prevents gastric acid stimulation by intravenous amino acids but fails to continuously raise intragastric pH above 4.

Adult↗