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Biomedical subjects

R Arnold

Publications and source records attributed to R Arnold.

At least 505 records · Page 28Linked to original sources
PubMed1984

Effect of antacid and H2-receptor blocker treatment on gastric endocrine cells.

It has been previously suggested that antral pH governs the density of antral G- and D-cells. Therefore, we investigated the effect of acid neutralization by an antacid (magaldrat; in vivo neutralization capacity of 144 mval/day) and the effect of suppression of gastric acid secretion by an H2-receptor blocker (oxmetidine, 400 mg/day) on the density of both cell types in healthy volunteers and duodenal ulcer patients. Four weeks after antacid treatment antral G-cell density decreased significantly in both groups, while antral D-cells decreased only in volunteers. Basal serum gastrin was not altered, whereas the integrated postprandial serum gastrin response and antral gastrin concentration was significantly reduced in volunteers but not in ulcer patients. None of the parameters investigated was changed by oxmetidine treatment. Considering the short-lasting effect on acid neutralization induced by the antacid dosage used in this study and the inability of oxmetidine treatment to influence volume densities and secretory activities of antral G- and D-cells it is concluded that mechanisms other than a change of antral pH may account for the results obtained during antacid treatment.

Adult↗
PubMed1984

Pancreatic polypeptide response to sham feeding in man.

The relationship between gastric acid secretion and the release of pancreatic polypeptide (PP) during modified sham feeding was studied in 29 duodenal ulcer patients and 10 healthy controls. Ulcer patients showed higher basal plasma PP levels than age-matched controls (p less than 0.01). Acid secretion and PP levels were stimulated in the majority of patients and controls during sham feeding; however, no correlation was found between basal and vagally stimulated acid secretion and basal PP levels. Gastrin levels did not change in both groups. It is concluded from the present study that changes in plasma PP levels do not reflect sham feeding induced stimulation of the parietal cells.

Adult↗
PubMed1983

Pulmonary artery growth during treatment with oral prostaglandin E2 in ductus dependent cyanotic congenital heart disease.

Growth of the pulmonary arteries was assessed in 11 patients with cyanotic congenital heart disease treated with oral prostaglandin E2. Each patient was dependent on patency of the ductus arteriosus for maintenance of the pulmonary circulation. Measurements were made initially from angiographic data obtained in the neonatal period. Subsequent assessments were made at the time of surgery after an interval of 2-8 months, during which time all the infants had gained weight normally. Comparisons were made with data obtained from 13 normal necropsy specimens. In only 4 of the 11 patients had the pulmonary arteries grown appreciably during the treatment period. In 2 patients no growth occurred, while in 5 patients the pulmonary arteries had actually become smaller. It had been hoped that the pulmonary arteries would grow in all 11 patients during this period, facilitating later surgical intervention. In patients with ductus-dependent cyanotic congenital heart disease, the prolonged use of oral prostaglandin E2 should be restricted to patients in whom the pulmonary arteries are too small to allow a palliative operation to be performed initially.

Body Weight↗
PubMed1983

Adrenergic control of rat gastric somatostatin and gastrin release.

The effect of adrenergic agonists and antagonists on the secretion of gastric somatostatin-like immunoreactivity (SLI) and gastrin was investigated in an isolated, vascularly perfused rat stomach preparation. Two- to six-fold increases in SLI secretion induced by isoproterenol, epinephrine, and norepinephrine were completely abolished by propranolol but were not influenced by phentolamine. Propranolol did not alter glucagon- and DB-cAMP-induced stimulation of SLI release. Experiments in which the beta 2-agonist salbutamol and the beta 1- and beta 2-blockers practolol and H35/25 were used showed that both subtypes of beta receptors are involved. Gastrin secretion revealed only minor changes in dose-response studies with a wide range of isoproterenol concentrations (2 X 10(-8) to 1.5 X 10(-4) M). The results obtained in this study suggest that in rats 1) the SLI response to adrenergic agonism is predominantly mediated by beta receptors; 2) both beta 1- and beta 2-adrenergic receptors are involved; 3) under in vitro conditions, adrenergic agonism is a weak stimulus for gastrin secretion.

Adrenergic beta-Agonists↗
PubMed1983

[Effect of drugs with acid-neutralizing and acid-suppressive effect on parietal cell function and on gastrin and somatostatin cell density of the stomach].

4 weeks treatment of healthy volunteers with Magaldrate (Al-Mg-containing antacid) is followed by an increase of basal serum gastrin, and a decrease of the antral G-cell density. Gastric acid secretion remained unchanged. In contrast, during maintenance therapy of duodenal ulcer patients with 400 mg cimetidine an increase of the postprandial gastrin output can be observed after 12 months treatment, whereas basal serum gastrin, antral G-cell density and gastric acid secretion remained unchanged. These results suggest that the effects observed during antacid treatment can not be related to an increase in gastric pH and may rather reflect a pH independent direct action of Magaldrate on the antral G-cell.

Adult↗
PubMed1983

The fate of cells with chromosome aberrations after total-body irradiation and bone marrow transplantation.

Cytogenetic studies were done on bone marrow cells and peripheral lymphocytes of four patients (three with acute nonlymphocytic leukemia, one with aplastic anemia) at various intervals up to 861 days after total-body X irradiation (TBI) at doses between 4.5 and 10 Gy (450-1000 rad) followed by syngeneic or allogeneic bone marrow transplantation. Whereas no radiation-induced aberrations could be found in the bone marrow, apart from a transient finding in the patient with the lowest radiation dose, aberrant metaphases were seen in the peripheral lymphocytes of three patients in the range from 2.5 to 46% even at 861 days after the exposure. There were no demonstrable aberrations related to TBI in the only patient developing graft-versus-host disease. The dicentric yield as determined in the aberrant metaphases with 46 centromeres ranged between 3.4 +/- 1.3 and 4.9 +/- 0.4. In one patient it was demonstrated by BUdR-labeling that after 10 Gy (1000 rad) TBI the surviving and heavily damaged lymphocytes can go into cell cycle and reach at least the third mitosis. The percentage of aberrant cells diminished by about 25% at each mitotic division.

Acute Disease↗
PubMed1983

[Hepatocellular drug reaction caused by mebendazole therapy in cystic echinococcosis].

A 76 years-old male patient received mebendazole, 500 mg four times a day (appr. 29 mg per kg body weight) for treatment of sonographically and serologically proven cystic echinococcosis of the liver. On day 49 of this therapy he developed an exanthema, and mebendazole-administration was interrupted. At the same time a striking rise of serum transaminases was observed. When enzyme levels normalized, a reexposure using a low dose of mebendazole lead to a new more pronounced rise of transaminases suggesting a drug-induced hepatocellular damage. No measurable change of the Echinococcus cyst was observed during treatment.

Aged↗
PubMed1982

Outcome of treatment for neonates referred to a supraregional cardiac centre 1976-78.

The clinical course and outcome of treatment for 322 consecutive neonates referred to a supraregional paediatric cardiac unit are reviewed. Two hundred and forty-eight (77%) had structural congenital cardiac defects. The remaining 74 (23%) presented with arrhythmia, nonstructural cardiorespiratory problems, or problems unrelated to the cardiovascular or respiratory system. Transposition of the great arteries and coarctation of the aorta were associated with a good prognosis. Infants with cyanotic cardiac defects associated with a low pulmonary blood flow who required early palliation were found to have a poorer outlook.

Actuarial Analysis↗
PubMed1982

Antral gastrin-producing G-cells and somatostatin-producing D-cells in different states of gastric acid secretion.

The number of G- and D-cells per area and the ratio of G/D-cells were investigated in biopsy specimens of the pyloric antrum from normochlorhydric subjects without peptic ulcer, from patients with duodenal ulcer, gastrinoma, pernicious anaemia, and after selective proximal vagotomy. Compared with normochlorhydric subjects antral G-cell density was significantly raised in pernicious anaemia, unchanged in duodenal ulcer, and diminished in gastrinoma patients. After vagotomy G-cell density was found to be raised if compared with patients with duodenal ulcer. D-cell density was significantly increased in gastrinoma patients, unchanged in duodenal ulcer, and diminished in pernicious anaemia and after vagotomy. The G/D-cell ratio was increased in pernicious anaemia and after vagotomy, unchanged in duodenal ulcer, and decreased in gastrinoma patients. It is concluded that the antral pH governs the ratio of G- and D-cells. Therefore, the G/D cell ratio increases in states of reduced acid secretion and decreases in massive hyperchlorhydria. Hypergastrinaemia as such does not affect the G/D-cell ratio.

Adult↗
PubMed1982

Adrenergic and cholinergic interactions in rat gastric somatostatin and gastrin release.

The interactions of adrenergic and cholinergic influences on the gastric D cell were studied using an isolated perfused rat stomach in vitro. The sevenfold increase in the release of somatostatin-like immunoreactivity (SLI) in response to isoproterenol (4 . 10(-8) M) was dose-dependently inhibited by acetylcholine (10(-5) to 10(-8) M) whereas gastrin levels increased in a dose-dependent manner. Both inhibition of stimulated SLI and augmentation of gastrin release were completely abolished by atropine (10(-6) M). Isoproterenol (8 . 10(-9) M)-induced stimulation of SLI secretion was not altered by atropine. Antral exclusion completely eliminated gastrin secretion but basal and beta-adrenergic stimulated SLI release was not influenced. It is concluded that (1) cholinergic agonism reverses the stimulatory action of adrenergic agonists on the D cell, and (2) SLI from the rat stomach in vitro originates almost exclusively in the fundic region.

Acetylcholine↗
PubMed1982

Effect of food deprivation on rat gastric somatostatin and gastrin release.

The influence of food deprivation on the release of somatostatin and gastrin from the rat stomach was investigated using an isolated, vascularly perfused rat stomach preparation. Basal and acetylcholine-stimulated gastrin release were significantly lower after a 3 day starvation, whereas the inhibitory effect of acetylcholine and the stimulatory effect of glucagon on somatostatin secretion were not influenced by fasting. In dose-response studies, isoproterenol dose-dependently stimulated somatostatin secretion. The increases were similar in both groups fasted for 12 and 72 h. Gastrin release remained at basal levels. Bombesin dose-dependently increased gastrin secretion; this stimulatory effect on the G cell was significantly reduced after a 72-h starvation. Somatostatin secretion was only weakly stimulated by high concentration of bombesin revealing no effect of fasting. Somatostatin content of the nonperfused stomach declined from 57 +/- 4 pmol/stomach in fed controls to 36 +/- 3 pmol/stomach after a 72-h fast. Antral gastrin concentration decreased by 42% in a 3-day fasting period. It is concluded that rat gastric somatostatin release in vitro is--in contrast to gastrin--not altered by food deprivation while the somatostatin content in gastric tissue declined during fasting.

Acetylcholine↗
PubMed1982

Infection prophylaxis in acute leukaemia patients: comparison of selective and total antimicrobial decontamination of the gastrointestinal tract.

In a retrospective study, total antimicrobial decontamination with strict reverse isolation (ITD) and selective decontamination without isolation (SD) were compared as means of preventing infection in patients with acute leukaemia. Thirty patients were treated with ITD and 34 patients with SD. The surveillance cultures indicated that aerobic gram-negative bacilli and yeast could be equally eliminated effectively in both the groups. The anaerobic flora was only minimally influenced by SD. The incidence of acquired infections was 1.17 per patient in group ITD as compared to 0.85 in group SD. In group ITD, acquired bacterial infections were mostly caused by gram-negative bacilli (63%) whereas in the group SD these microorganisms accounted only for 25% of the infections. In group SD the total number of fever days was significantly lower and the mean duration of pyrexial episodes was substantially shorter. The results indicate that SD is an effective and inexpensive method for preventing gram-negative infections and might be at least as effective as ITD.

Acute Disease↗