Biomedical subjects

J B Jansen

Publications and source records attributed to J B Jansen.

At least 163 records · Page 9Linked to original sources

PubMed1992

Effect of loxiglumide and atropine on erythromycin-induced reduction in gallbladder volume in human subjects.

This study was undertaken to investigate the effect of erythromycin, a motilin agonist with prokinetic activity, on fasting gallbladder volume. To evaluate the mechanism of action of erythromycin on gallbladder motility, erythromycin (3.5 mg/kg.20 min, intravenously) was infused on three separate occasions: during cholinergic blockage with atropine (0.005 mg/kg.hr), during cholecystokinin receptor blockade with loxiglumide (10 mg/kg.hr) and during saline solution infusion (control). Atropine, loxiglumide and saline solution infusions were started 3 hr before administration of erythromycin and were continued for 3 hr thereafter. Gallbladder volumes (measured by ultrasonography), plasma cholecystokinin levels (radioimmunoassay) and plasma pancreatic polypeptide levels (radioimmunoassay) were determined at regular intervals for 6 hr in six healthy volunteers. During the 3-hr infusion before administration of erythromycin, both loxiglumide and atropine significantly increased gallbladder volumes--from 18 +/- 2 to 37 +/- 3 cm3 (p less than 0.05) and from 17 +/- 3 to 24 +/- 2 cm3 (p less than 0.05), respectively--whereas saline solution did not significantly affect gallbladder volume. During control saline solution infusion, erythromycin induced prolonged gallbladder contraction that was significant (p less than 0.05) between 60 and 180 min and reached a maximum of 45% +/- 8% at 150 min. Plasma cholecystokinin levels were not affected by erythromycin. Erythromycin induced a significant (p less than 0.05) increase in plasma pancreatic polypeptide levels, from 12 +/- 1 pmol/L to 34 +/- 3 pmol/L. Loxiglumide did not prevent the erythromycin-induced reduction in gallbladder volume. Atropine markedly reduced the effect of erythromycin, causing slight but significant (p less than 0.05) gallbladder volume reductions (18% +/- 4%) between 150 and 180 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Influence of single- and multiple-dose omeprazole treatment on nifedipine pharmacokinetics and effects in healthy subjects.

The effects of single dose (20 mg) and short-term (20 mg/day for 8 days) oral treatment with omeprazole on the pharmacokinetics and effects of oral nifedipine (10 mg capsule) and on gastric pH have been investigated in a randomized, double-blind, placebo-controlled cross-over study in 10 non-smoking healthy male subjects. The single dose of omeprazole had no significant effect on any pharmacokinetic parameter of nifedipine, nor on gastric pH, or blood pressure or heart rate. Short-term omeprazole treatment increased the AUC of nifedipine by 26% (95% confidence interval 9-46%), but all other pharmacokinetic parameters of nifedipine, including elimination half-life, Cmax, tmax, and recovery of the main urinary metabolite, were not significantly changed. The median gastric pH during the absorption phase of nifedipine was increased by short-term omeprazole (pH 4.2) compared to placebo treatment (pH 1.4). Blood pressure and heart rate did not differ between treatments. The interaction between nifedipine and omeprazole is not likely to be of major clinical relevance.

Adult↗

PubMed1992

Postprandial gallbladder motility and plasma cholecystokinin at regular time intervals after injection of octreotide in acromegalics on long-term treatment.

The increased risk of gallstone formation in acromegalics treated with the somatostatin analog octreotide has been related to an impaired gallbladder emptying. To determine the duration of these inhibitory effects, meal-stimulated gallbladder motility, plasma cholecystokinin (CCK), and pancreatic polypeptide (PP) were measured in five acromegalics treated for 6-32 months with 200-300 micrograms octreotide daily. Meal tests were performed 45 min, 8 hr and two weeks after the last 100-micrograms subcutaneous dose. Results were compared with those in normal subjects. Integrated postprandial gallbladder contraction (-125 +/- 194 cm3/120 min) and integrated PP secretion (-0.1 +/- 0.2 nmol/liter/120 min) were completely suppressed in the 45-min study, but significantly improved (P < 0.05) when measured 8 hr (1376 +/- 322 cm3/120 min and 3.0 +/- 1.0 nmol/liter/120 min) and two weeks (1437 +/- 263 cm3/120 min and 10.6 +/- 1.6 nmol/liter/120 min) after the last dose of octreotide. The integrated gallbladder contraction in acromegalics at 8 hr was comparable to that at two weeks and to that in normal subjects, but the integrated PP response at 8 hr was significantly smaller (P < 0.05 vs two weeks and vs normals). Integrated plasma CCK secretion at 45 min (0.13 +/- 0.06 nmol/liter/120 min) was not statistically significantly different from the response at 8 hr (0.15 +/- 0.02 nmol/liter/120 min) and from that in normal subjects, but it was significantly increased at two weeks after cessation of octreotide (P < 0.05 vs 45 min and 8 hr).(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly↗

PubMed1992

Effect of loxiglumide on basal and gastrin- and bombesin-stimulated gastric acid and serum gastrin levels.

The effect of the specific cholecystokinin-receptor antagonist loxiglumide on basal and bombesin-, and gastrin 17-I-stimulated gastric acid secretion and serum gastrin levels was studied in 12 healthy subjects. Loxiglumide (10 mg.kg-1.h-1) significantly augmented basal gastric acid output from 1.8 +/- 0.3 to 3.9 +/- 0.6 mmol H+/h (P less than 0.005) but did not significantly influence integrated basal serum gastrin concentrations (2 +/- 21 vs. 32 +/- 21 pmol L-1.h-1). Both gastric acid secretion and integrated serum gastrin concentrations stimulated by bombesin infusion (92.6 pmol.kg-1.h-1) were significantly augmented by loxiglumide [from 4.0 +/- 0.3 to 10.0 +/- 1.3 mmol H+/h (P less than 0.005) and from 1251 +/- 93 to 2558 +/- 206 pmol.L-1.h-1 (P less than 0.005), respectively]. Gastric acid output and serum gastrin concentrations during infusion of 5 pmol.kg-1.h-1 of synthetic human gastrin 17-I (9.6 +/- 2.9 mmol H+/h and 1045 +/- 177 pmol.L-1.h-1) and during infusion of 15 pmol.kg-1.h-1 of gastrin 17-I (14.5 +/- 3.1 mmol H+/h and 2412 +/- 312 pmol.L-1.h-1) were not significantly influenced by loxiglumide (10.3 +/- 2.3 mmol H+/h and 1291 +/- 257 pmol.L-1.h-1 for the 5-pmol.kg-1.h-1 gastrin 17-I infusion dose with loxiglumide and 13.6 +/- 3.4 mmol H+/h and 2611 +/- 305 pmol.L-1.h-1 for the 15-pmol.kg-1.h-1 gastrin 17-I infusion dose with loxiglumide). These data indicate that endogenous cholecystokinin inhibits gastric acid secretion under basal conditions and gastrin release and gastric acid secretion during infusion of bombesin in humans and suggest that the augmented effect of loxiglumide on bombesin-stimulated gastric acid secretion may be explained largely by enhanced gastrin release.

Adult↗

PubMed1992

Fasting gallbladder volume, postprandial emptying and cholecystokinin release in gallstone patients and normal subjects.

Since abnormal gallbladder emptying may be a contributing factor in the development of gallstone disease, we determined fasting gallbladder volume and postprandial contraction in 20 gallstone patients and 20 normal subjects with the aid of ultrasonography. Moreover, basal plasma cholecystokinin levels and postprandial cholecystokinin (CCK) release were determined. Gallstone patients were divided into strong contractors (13 pts) and weak contractors (below 95% confidence interval for AUC contraction in % during 90 min: 7 pts). Strong contractor patients had significantly larger mean fasting volumes than normal subjects (mean +/- S.E.: 34.9 +/- 6.1 ml and 18.9 +/- 1.6 ml, respectively). This was not true for weak contractor patients (mean fasting volume 23.2 +/- 3.2 ml). Both strong contractor and weak contractor patients had significantly higher mean residual volumes than normal subjects (17.0 +/- 4.1 ml, 18.0 +/- 2.9 ml, and 8.8 +/- 1.1 ml, respectively). Absolute gallbladder emptying was significantly higher for strong contractor patients than for normal subjects, but relative emptying was the same. Opposite patterns of CCK release occurred in gallstone patients and normal subjects. In normal subjects, more CCK release was associated with stronger gallbladder emptying. In contrast, weak contractor gallstone patients had significantly higher CCK release than strong contractor patients. (AUC CCK: 304 +/- 89 pmol/l x 90 min and 106 +/- 29 pmol/l x 90 min, respectively). The present study indicates that strong contractor gallstone patients may have large residual gallbladder volumes due to large starting volumes, whereas weak contractor patients may have large residual volumes due to impaired contraction. Subjects with large fasting and residual volumes may be at increased risk for gallstone disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholecystokinin↗

PubMed1992

Role of cholecystokinin in dietary fat-promoted azaserine-induced pancreatic carcinogenesis in rats.

The role of cholecystokinin in dietary fat-promoted pancreatic carcinogenesis was investigated in azaserine-treated rats, using lorglumide, a highly specific cholecystokinin-receptor antagonist. The animals were killed 8 months after the start of treatment. Cholecystokinin, but not dietary unsaturated fat, increased pancreatic weight. Rats treated with cholecystokinin developed more acidophilic atypical acinar cell nodules, adenomas and adenocarcinomas than control animals. Rats maintained on the high-fat diet developed significantly more adenomas and adenocarcinomas than controls given a diet low in unsaturated fat. Lorglumide largely inhibited the enhancing effect of cholecystokinin, but not of dietary fat, on pancreatic carcinogenesis indicating that it is unlikely that the promoting effect of dietary unsaturated fat on pancreatic carcinogenesis is mediated via cholecystokinin.

Animals↗

PubMed1992

Effects of cholecystokinin and bombesin on development of azaserine-induced pancreatic tumours in rats: modulation by the cholecystokinin receptor antagonist lorglumide.

Cholecystokinin and bombesin have been shown to promote pancreatic growth and development of azaserine-induced acidophilic atypical acinar cell nodules in rat pancreas after treatment for 16 weeks. Lorglumide, a specific cholecystokinin receptor antagonist, inhibited the stimulating effect of cholecystokinin, but not of bombesin. The present study was carried out to determine effects of cholecystokinin and bombesin, alone and in combination with lorglumide, on pancreatic growth and carcinogenesis after chronic treatment. The animals were killed 8 months after the start of treatment. Growth of the pancreas and the development of acidophilic atypical acinar cell nodules in exocrine pancreas was enhanced significantly by both cholecystokinin and bombesin, but the number of carcinomas was increased only by bombesin. Lorglumide inhibited the effects of cholecystokinin on both pancreatic growth and on the development of acidophilic nodules. The effects of bombesin on pancreatic growth and development of pancreatic lesions, except for adenomas, were not inhibited by lorglumide.

Animals↗

PubMed1992

Exocrine pancreatic insufficiency and pancreatic fibrosis due to duodenal somatostatinoma in a patient with neurofibromatosis.

A case of duodenal somatostatinoma is described in a patient with Von Recklinghausen neurofibromatosis. The patient presented with exocrine pancreatic insufficiency, probably due to distal obstruction of the pancreatic duct by the tumor. Preoperative evaluation with calcium-pentagastrin and tolbutamide stimulation tests were nondiagnostic. At laparotomy, local excision of the tumor was performed. Pathological findings were compatible with duodenal somatostatinoma, causing pancreatic fibrosis. Somatostatin extracted from the tumor coeluted with the somatostatin-14 standard on high performance liquid chromatography (HPLC).

Adult↗

PubMed1992

Does smoking influence the pharmacokinetics and pharmacodynamics of the H2-receptor antagonist famotidine?

Twelve healthy habitual cigarette smokers and eight non-smokers participated in a double-blind placebo controlled study to determine the effect of smoking on the pharmacokinetics and pharmacodynamics of the H2-receptor antagonist famotidine. In smokers, cigarette smoking was standardised and started 1 h before (A), or 2 h after (B) drug administration, or was prohibited (C). Intragastric pH-levels (IGpH) were measured with an ambulatory pH-recorder. Famotidine (40 mg orally) significantly raised median 22 h IGpH in non-smokers and smokers in all study periods. The smoking sequence (A, B, C) did not significantly influence median 22 h IGpH in both placebo-treated and famotidine-treated smokers, and no significant difference in median 22 h IGpH was shown between smokers and non-smokers. Plasma drug concentrations were similar in the various experiments, although famotidine was detected earlier in plasma from non-smokers compared with smokers (P less than 0.05). Smoking did not interfere significantly with the pharmacokinetics and pharmacodynamics of famotidine.

Adult↗

PubMed1992

Pancreatic morphology and function in adult patients with cystic fibrosis.

To determine the relation between pancreatic morphology and pancreatic exocrine and endocrine function, we have studied 8 adult cystic fibrosis patients and 14 normal control subjects by ultrasonography and pancreatic function testing. In the patients with cystic fibrosis the maximum anteroposterior diameter of the pancreatic head was significantly increased over that in control subjects (p less than 0.01), whereas the maximum diameter of the body was significantly decreased (p = 0.05). Increased echogenicity of the pancreatic body was observed in most patients. In the cystic fibrosis patients postprandial insulin secretion was reduced in the 1st h (p less than 0.005 versus control), whereas pancreatic polypeptide secretion was virtually abolished for at least 3 h (p less than 0.01 versus control). All cystic fibrosis patients had evidence of exocrine pancreatic dysfunction as reflected by a diminished urinary para-aminobenzoic acid excretion. Intraduodenal enzyme and bicarbonate output in response to secretin-cholecystokinin was reduced in all of three patients studied. It is concluded that loss of endocrine and exocrine pancreatic function in adult cystic fibrosis patients is accompanied by a small and echo-dense pancreatic body relative to a large pancreatic head.

4-Aminobenzoic Acid↗

PubMed1992

Gastric abnormalities in humoral immune deficiency syndromes.

Patients with late-onset hypogammaglobulinaemia have a very high risk of developing gastric cancer. In such patients there is a high frequency of atrophy of the gastric mucosa. This is reflected in low gastrin content of the antral mucosa, low serum pepsinogen A level and pepsinogen A/C ratio, and reduced serum gastrin secretion in response to bombesin stimulation. There is no evidence to support a role of Helicobacter pylori infection in the aetiopathology of these gastric abnormalities, although prior infection cannot be excluded with certainty. Since patients with early-onset hypogammaglobulinaemia and X-linked agammaglobulinaemia do not show this increased frequency of gastric abnormalities, it is unlikely that the immunoglobulin deficiency per se is responsible for the development of the gastric abnormalities found in patients with late-onset hypogammaglobulinaemia. Because of the very high risk of gastric cancer, regular endoscopic screening is warranted in patients with late-onset hypogammaglobulinaemia.

Agammaglobulinemia↗

PubMed1992

A decade of experiences with radioimmunoassays for cholecystokinin in The Netherlands.

The radioimmunologic determination of cholecystokinin (CCK) has proved to be notoriously difficult. This is due to the specificity of antibodies, preparation of radiolabeled CCK and low CCK concentrations in human plasma. About 10 years ago we succeeded in developing two highly sensitive region-specific radioimmunoassays for CCK. Antibody T204 binds to the sulfated tyrosine region of CCK, while antibody 1703 reacts with biologically active molecular forms of CCK containing at least 14 amino acid residues. Both antibodies are devoid of significant cross-reaction with gastrin. By means of these two radio-immunoassays CCK concentrations were measured in both tissue and plasma of various species, including man. In addition, the molecular forms of CCK in tissue and plasma were characterized. These CCK assays were used to study the mechanism of CCK secretion. It appeared that digested rather than intact protein and fat stimulated CCK release from the small intestine. The physiologic and pathophysiologic role of CCK in humans was studied using CCK radioimmunoassays and specific CCK-receptor antagonists. CCK was found to play an important role in pancreatic enzyme secretion, gallbladder contraction, and gastrointestinal motility but possibly also in pancreatic carcinogenesis and regulation of satiety and satiation.

Animals↗

PubMed1992

Short-term results of gastrectomy with Roux-en-Y or Billroth II anastomosis for peptic ulcer. A prospective comparative study.

Since the Roux-en-Y anastomosis prevents the sequela of postoperative enterogastric reflux after gastrectomy, this approach has been advocated as the primary procedure in patients undergoing gastrectomy for peptic ulcer. We have prospectively followed for 2 years 22 patients, in whom gastrectomy was performed with, at random, either Roux-en-Y (n = 11) or Billroth II (n = 11) anastomosis. Two of the 11 patients who had received the Roux-en-Y procedure had anastomotic ulcers, leading to reresection in one of them. These two patients were found to have the highest values for basal and pentagastrin stimulated gastric acid output. After the Billroth II procedure a single patient had a small anastomotic ulcerative lesion. Apart from differences in intragastric bile acids (p less than 0.0001) and the gastritis activity score (p less than 0.01), no significant differences were found between the patients with Roux-en-Y and Billroth II anastomosis with respect to basal and pentagastrin-stimulated gastric acid secretion, basal, postprandial and bombesin-stimulated serum gastrin secretion, serum pepsinogen A and C concentrations, the serum pepsinogen A/C ratio, postprandial glucose, and for a modified Visick grading. From this small series we conclude that, as compared with the Billroth II-anastomosis, the Roux-en-Y procedure effectively prevents enterogastric reflux, and is associated with a higher gastritis activity score, but not with differences in gastric acid, gastrin, pepsinogens, or Visick grading. Furthermore, inadequate reduction of acid secretion in some patients after the Roux-en-Y procedure may lead to recurrent peptic ulcers.

Anastomosis, Roux-en-Y↗

PubMed1991

Effects of the synthetic trypsin inhibitor camostate on the development of N-nitrosobis(2-oxopropyl)amine-induced pancreatic lesions in hamsters.

Trypsin inhibitors have been shown to promote pancreatic growth as well as the development of pancreatic tumours in rats. The present study was carried out to examine the effects of the synthetic trypsin inhibitor camostate on the growth of the pancreas and on the development of pancreatic preneoplastic and neoplastic lesions in hamsters treated with N-nitrosobis(2-oxopropyl)amine. A specific cholecystokinin-receptor antagonist was administered to determine the role of cholecystokinin in camostate action. The animals were killed 19 weeks after the first injection with N-nitrosobis(2-oxopropyl)amine. Camostate caused an increase in growth of the pancreas and a decrease in the number of (pre)neoplastic ductular pancreatic lesions. Lorglumide (CR-1409) did not influence these effects of camostate. It was concluded that rats and hamsters behave differently with regard to the effect of camostate on pancreatic growth and carcinogenesis.

Animals↗

PubMed1991

Human gastrin-releasing peptide: biological potency in humans.

Gastrin-releasing peptide (GRP) was infused in graded doses (1-27 pmol/kg per h) to healthy human volunteers to study the effects on gastric, pancreatic and gallbladder functions as well as on gastrin, CCK and PP release. The results were compared to equimolar doses of synthetic bombesin. GRP significantly (P less than 0.05) stimulated gastric and pancreatic secretory responses, gallbladder contraction and gastro-enteropancreatic hormone release in a dose-dependent manner. GRP was found to be equipotent to bombesin with respect to gastric acid secretion, pancreatic enzyme output, gallbladder contraction and plasma hormone release. We conclude (a) that human GRP has similar biologic effects as synthetic bombesin; (b) as GRP is localized exclusively in nerve tissue and has potent effects on different organs, it is a likely candidate for peptidergic control of human gastric, pancreatic and gallbladder functions.

Adult↗

PubMed1991

Effects of bombesin on the development of N-nitrosobis(2-oxopropyl)amine-induced pancreatic lesions in hamsters.

Bombesin (BBS) has been shown to promote pancreatic growth as well as the development of pancreatic (pre)neoplasia in rats. The present study was carried out to determine the effects of bombesin on pancreatic growth and on the development of pancreatic (pre)neoplastic lesions in hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). Bombesin caused an increase in growth of the pancreas accompanied by a decrease in the number of (pre)neoplastic ductular pancreatic lesions. Lorglumide (CR-1409) did not influence these effects of bombesin. It is concluded that in BOP-treated hamsters the effect of bombesin on the pancreas is not mediated by cholecystokinin (CCK). These data support the existence of species difference between rats and hamsters with regard to the effect of bombesin on pancreatic carcinogenesis.

Animals↗

PubMed1991

Inhibition of meal-stimulated gastric acid secretion by gastrin immunoneutralization in rats.

Gastrin 17-I was infused into conscious rats equipped with jugular and portal vein catheters and with a pyloric gastric drainage tube to achieve serum concentrations slightly higher than those found during intragastrically instilled peptone solutions. I.v. injected rabbit gastrin antiserum abolished gastrin 17-I-stimulated gastric acid secretion in these animals. Gastrin immunoneutralization reduced peptone-stimulated gastric acid secretion by approximately 37% during the entire 30-min period of stimulation. Peptone-stimulated gastric acid secretion was only significantly (P less than 0.05) inhibited in the third 10-min period, but not in the first or second 10-min periods of stimulation. This study demonstrates that the late but not the initial period of peptone-stimulated gastric acid secretion is regulated by circulating gastrin in rats.

Animals↗

PubMed1991

Effect of the specific cholecystokinin-receptor antagonist loxiglumide on bombesin stimulated pancreatic enzyme secretion in man.

We have investigated the effects of the specific cholecystokinin (CCK) receptor antagonist loxiglumide on basal and bombesin stimulated pancreatic enzyme secretion, bilirubin output and plasma CCK release in six healthy subjects. The data were compared with those obtained in control experiments where saline was infused instead of loxiglumide. Basal amylase output (4.7 +/- 0.8 kU/45 min), trypsin output (2.9 +/- 0.8 kU/45 min) and bilirubin output (7.7 +/- 2.8 mmol/45 min) gradually declined during infusion of loxiglumide to values of 1.3 +/- 0.3 kU/45 min, 0.5 +/- 0.1 kU/45 min and 0.4 +/- 0.0 mmol/45 min, respectively, reaching statistical significance (P less than 0.05) in the 30 to 45-min period after the start of the loxiglumide infusion. In the control experiments saline infusion failed to influence basal amylase, trypsin and bilirubin output, while bombesin stimulated amylase output from 4.7 +/- 0.8 kU/45 min to 25.1 +/- 5.1 kU/45 min (P less than 0.05), trypsin output from 2.9 +/- 0.8 kU/45 min to 11.6 +/- 2.0 kU/45 min (P less than 0.05) and bilirubin output from 7.7 +/- 2.8 mmol/45 min to 68.0 +/- 16.0 mmol/45 min (P less than 0.05). Loxiglumide failed to significantly influence bombesin stimulated amylase output (36.7 +/- 9.0 kU/45 min) and trypsin output (8.3 +/- 2.9 kU/45 min), but almost abolished bilirubin output (9.7 +/- 3.6 mmol/45 min) (P less than 0.05). Basal plasma CCK (2.4 +/- 0.1 pM) was not significantly influenced by loxiglumide (2.4 +/- 0.2 pM).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗