Biomedical subjects

D Andersen

Publications and source records attributed to D Andersen.

At least 91 records · Page 5Linked to original sources

PubMed1981

Effect of isoprenaline on pentagastrin-stimulated gastric acid secretion in dogs with gastric fistula.

The purpose of this study was to elucidate the effect of a beta 1-adrenoceptor agonist on gastric acid secretion in conscious dogs with gastric fistula. Isoprenaline, a beta 1- and beta 2-agonist was used alone and in conjunction with selective blockade of beta 2- and beta 1-receptors. Isoprenaline dose-dependently inhibited the secretory volume and the acidity. The antisecretory effect of isoprenaline was significantly blocked by the beta 1-adrenoceptor blocker practolol and by the beta 1 + beta 2-adrenoceptor blocker propranolol but not by H 35/25, a beta 2-adrenoceptor blocker. This indicates that isoprenaline acts on the acid secretion exclusively through beta 1-receptors. Dose-response experiments with five logarithmically increased doses of pentagastrin and one dose of isoprenaline showed unchanged calculated maximum response and an increase in half-maximum acid response. It is concluded that the inhibitory effect of isoprenaline on gastric acid secretion is of competitive or uncompetitive type.

Adrenergic beta-Antagonists↗

PubMed1981

Effect of a beta 2-sympathomimetic on gastrin release, acid secretion, and blood glucose during basal conditions and in response to insulin, 2-deoxy-D-glucose, and feeding in the dog.

The effect of a selective beta 2-adrenoceptor agonist on basal volume and on insulin-, 2-deoxy-D-glucose (2-DG)-, and food-induced gastrin release was studied in conscious gastric fistula dogs. Acid output and blood glucose changes were also studied, except in the food experiments. Basal acid secretion and serum gastrin were unchanged after beta 2-sympathetic infusion, whereas a slight increase in blood and glucose was found. The beta 2-agonist almost prevented acid output and gastrin release after insulin hypoglycaemia. However, the hypoglycaemia was also inhibited. Gastric acid secretion stimulated by 2-DG was inhibited, as was probably the gastrin release. 2-DG increased the blood glucose level, and no significant differences were found after beta 2 infusion. After feeding, gastrin release was initially decreased for one of five doses of the beta 2-agonist, and higher doses of the beta 2-agonist prevented the subsequent fall in serum gastrin after the initial peak value. This pattern was also found for the histamine H2-blocker cimetidine in a dose that blocks acid output. The beta 2-agonist and 2-DG increased pulse rate. It is concluded that beta 2-sympathetic stimulation inhibits acid output and gastrin release after insulin and 2-DG stimulation, but one should be cautions in drawing conclusions from the insulin experiments. The effect on gastrin release is small compared with the effect on the acid secretion, and it is unlikely that the inhibition of acid secretion acts through a change in gastrin release.

Animal Feed↗

PubMed1981

Characterization of protein carboxyl methylase activities in rat testis: presence of testis specific charge isomers.

The physicochemical and molecular properties of testicular Protein Carboxyl Methylase (PCM) have been studied. The testicular enzyme was stable at high ionic strength, independent of metal ions and resistant to reducing or alkylating agents, and displayed a narrow pH optimum of pH 5.8-6.0. The enzyme had a molecular weight of approximately 25,000 daltons and a Km for S-adenosyl-L-methionine (SAM) of 1.3 microM. Varying concentrations of gelatine (exogenous methyl acceptor protein) did not change the affinity of the enzyme for SAM. The molecular properties of the enzyme were characterized using gel filtration, hydroxyapatite and DEAE-cellulose chromatography, and isoelectric focusing. Three charge isomers exhibiting PCM activity were isolated with pI values of 6.1, 6.7, and 7.35 while comparative data from the pituitary gland revealed primarily the presence of the most acid isozyme (pI 6.1). These results suggest that the different testicular charge isozymes may be involved in the selective methylation of specific testicular proteins.

Animals↗

PubMed1981

The antrum in duodenal ulcer patients. Relationship between antrum size, nerve of Latarjet, gastrin cell quantity, and gastric acid secretion.

Estimates of the border between antral and fundic mucosa, antral size, antral G-cell density, G-cell population, and total G-cell volume were made from multiple biopsies taken from the gastric curves during parietal cell vagotomy for duodenal ulcer in 33 patients. No relation was found between the landmarks of Latarjet's nerve and the border. The fundic mucosa was underdenervated in 20% of the patients, and the postoperative acid response to sham feeding in these was higher than in patients with an overdenervated or optimally denervated border. No relation was found between antral size, defined as antral mucosal volume containing G-cells, and preoperative acid secretion. However, an inverse relation was found between antral size, defined as antral mucosal volume containing no parietal cells, and preoperative maximum acid secretion, suggesting an inverse relation between areas with and without parietal cells. No relation was found between acid secretion and G-cell densities, G-cell population, or total G-cell volume.

Cell Count↗

PubMed1980

LH/hCG responsive adenylyl cyclase in rat testis and testes from testicular feminized male (Tfm) rats and mice; desensitization by homologous hormone.

Testes of testicular feminized (tfm) rats and mice, as well as of normal male rats contain an LH/hCG responsive adenylyl cyclase. Basal, as well as hCG stimulated activities were higher in tfm rats and mice than in normal rats. The presence of an LH/hCG responsive adenylyl cyclase in the testis of tfm rats and mice shows that the greatly elevated LH levels present in males having this syndrome, giving 80-90% reduction in LH/hCG receptors, do not cause an uncoupling of the remaining receptors from the adenylyl cyclase. It also shows that androgens are not essential for coupling of the LH/hCG receptors to the adenylyl cyclase. Injection of 200 IU of hCG into adult normal rats and tfm rats caused, after 48 h, a complete loss of LH/hCG stimulated adenylyl cyclase whereas the FSH responsive adenylyl cyclase in both animal preparations was maintained. Desensitization of the LH responsive adenylyl cyclase by hCG in normal rats, confirms previous studies showing lack of hCG stimulated cyclic-AMP secretion after a comparable dose of hCG in vivo. Similarly, hCG (50 IU) caused a transient loss of LH/hCG responsive adenylyl cyclase in tfm mice, with a complete disappearance of response after 24 h. At 48 and 72 h after injection of hCG the response gradually returned to normal. The fact that hCG caused a complete desensitization of the LH/hCG responsive adenylyl cyclase in both tfm rats and mice, proves that androgen receptor mediated events are not involved in hCG desensitization of the adenylyl cyclase in Leydig cells.

Adenylyl Cyclases↗

PubMed1980

X-ray examination and/or endoscopy in the diagnosis of gastroduodenal ulcer and cancer.

The diagnostic value of barium meal and endoscopy for the diagnosis of gastric ulcer and cancer was studied in 173 unselected patients with upper abdominal dyspepsia. The predictive value of both positive and negative results was higher for endoscopy than for barium meal. This was also found in earlier studies comprising hospitalized patients, with a consequent higher prevalence of disease, but this study shows that the superiority of endoscopy is maintained in a low-prevalence outpatient population. The diagnostic efficiency of both endoscopy and X-ray was independent of the order of examination. Knowledge of the result of the first examination thus did not improve the efficiency of the second one. Parallel use of endoscopy and barium meal results in a maximum of diagnostic yield but requires the highcost of double examination and supplementary examinations in cases of discrepancy between the two results. Routine use of barium meal with selective use of endoscopy in X-ray-positive cases requires a smaller number of examinations but results in the loss of an unacceptable number of diagnoses. When both costs and diagnostic yield are considered, endoscopy seems to be the examination of choice, with X-ray examination reserved for exceptional cases when endoscopy for one reason or another cannot be carried out. Hospital facilities should be planned with the aim of developing endoscopic services capable of taking over the traditional leading role of X-ray examination in the gastroduodenal field.

Adolescent↗

PubMed1980

Acid response to sham feeding as a test for completeness of vagotomy.

The reproducibility of acid responses to modified sham feeding by the chew-and-spit technique (PAOsh) was investigated in 21 duodenal ulcer (DU) patients 8 to 14 days after vagotomy. Possible relationships between PAOsh and the acid response to 0.2 U of insulin per kilogram body weight were examined (PAOI) in 23 other DU patients 8 to 14 days after vagotomy. PAOsh was reproducible to a high degree (PSpearman less than 0.001, CV 2.9%), and a highly significant relationship was found between PAOsh and PAOI after vagotomy (PSp less than 0.001). PAOsh and PAOI were similar when PAOI was low, whereas a highly incomplete vagotomy according to PAOI was followed by a somewhat lower, but substantial, acid response to sham feeding. The relationship between PAOsh and PAOI permits the recommendation of modified sham feeding as a safe stimulant of acid secretion in quantitative testing of completeness of vagotomy.

Adult↗

PubMed1980

Effect of two types of beta-adrenergic blockade on gastric acid secretion during basal conditions and during histamine stimulation on non-vagotomized and in vagotomized gastric fistula dogs.

The effect of beta-adrenoreceptor blockade by propranolol and practolol on basal secretion and on submaximally histamine-stimulated gastric acid secretion was studied in conscious non-vagotomized and in vagotomized gastric fistula dogs. Neither propranolol (0.5 mg/kg) nor practolol (1.0 mg/kg), both intravenously, had a significant influence on basal or histamine-stimulated gastric acid secretion in non-vagotomized and vagotomized dogs. It is concluded that beta-adrenergic blockade has no influence on basal or histamine-stimulated gastric acid secretion in dogs. Furthermore, no differences were found between the non-vagotomized and the vagotomized stomach.

Adrenergic beta-Antagonists↗

PubMed1980

Effect of beta 2-sympathomimetic on pentagastrin- and histamine-stimulated gastric acid secretion in vagotomized gastric fistula dogs.

The effect of a beta 2-adrenoceptor agonist on pentagastrin- and histamine-stimulated gastric acid secretion was studied in conscious vagotomized gastric fistula dogs. A dose-dependent inhibition was found after pentagastrin stimulation, whereas minor differences were found after histamine stimulation. No major differences between truncal, selective, and parietal cell vagotomy were found after pentagastrin stimulation, whereas one truncal vagotomy dog showed a high inhibition after histamine stimulation. Dose-response experiments with five doses of pentagastrin or histamine (single-dose studies) and two doses of beta 2-agonist suggested a change after vagotomy in the mechanisms of inhibition of gastric acid secretion: for pentagastrin, from a non-competitive type to an uncompetitive type, and for histamine, from a competitive type to a non-significant inhibition. Furthermore, the dose-response curves for the vagotomized dogs were very similar to the curve from intact innervated dogs inhibited by a beta 2-agonist, from an earlier study. These findings may indicate that a decrease in cholinergic tone and an increase in sympathetic tone have identical effects on pentagastrin- and histamine-stimulated gastric acid secretion, and a counterbalance between the two nervous systems on gastric acid secretion is suggested.

Adrenergic beta-Agonists↗

PubMed1979

Biopsy and brush cytology in the diagnosis of gastric cancer.

In a prospective study the diagnostic value of biopsy and that of brush cytology in the diagnosis of gastric cancer were compared. The patients included in the study were endoscopied because of upper abdominal dyspepsia. When the endoscopic appearance of the mucosa suggested malignancy, and in all cases in which ulcerations were seen, brush cytological smear and at least five biopsies were obtained. The cytology and the biopsy specimens were assessed by two different pathologists in a mutual blind fashion. If the result of the examination suggested or showed the presence of cancer, it was considered positive. The results were evaluated by means of sequential analysis. When 195 examinations had been included in the study, disagreement had occurred in 8 cases, in all of which the biopsy was verified as correct. This difference is significant. In 187 cases the result of the 2 tests were in agreement, but in 3 cases the result of both tests were falsely negative. It was concluded that no diagnostic advantage was gained by the addition of brush cytology to endoscopic biopsy.

Adult↗

PubMed1979

Effect of two types of beta-adrenergic blockade on gastric acid secretion during pentagastrin stimulation in non-vagotomized and in vagotomized gastric fistula dogs.

The effect of beta-adrenoceptor blockade by propranolol and practolol on submaximally pentagastrin-stimulated gastric acid secretion was studied in conscious non-vagotomized and in vagotomized gastric fistula dogs. Propranolol (0.5 mg/kg) intravenously augmented gastric acid output in vagotomized dogs, more after truncal and selective vagotomy than after parietal cell vagotomy. Vagally innervated dogs also showed an increase, but to a lesser degree and not statistically significant. The increase restored the acid output to preoperative levels in the vagotomized dogs. Practolol (1.0 mg/kg) intravenously resulted in a slight and insignificant increase in acid output in dogs with truncal vagotomy and had only a negligible effect in vagally innervated dogs and after selective and parietal cell vagotomy. It is concluded that propranolol augments pentagastrin-stimulated acid output in vagotomized dogs, and this augmentation was most pronounced in the totally vagotomized stomach. Practolol had minor influence on gastric acid secretion. This effect of the two beta-blocking agents indicates that beta 2-blockade is most important for the secretory augmentation. The restoration of postvagotomy acid secretion to preoperative levels suggests that adrenergic influence is important for the decrease in pentagastrin-stimulated acid secretion after vagotomy.

Adrenergic beta-Antagonists↗

PubMed1978

Prophylaxis against postoperative pulmonary embolism and deep-vein thrombosis by low-dose heparin.

The prophylactic effect of low-dose heparin on postoperative fatal and on clinically apparent but non-fatal thromboembolic complications was studied in a double-blind, prospective, randomised study comprising 1296 patients. 16 out of 653 patients in the placebo group had such complications within the treatment period of 1 week, compared with 4 out of 643 in the heparin group. This difference was statistically significant (P less than 0.05). 4 cases in the placebo group and 1 in the heparin group were fatal. After prophylactic treatment had been stopped at the end of the first postoperative week, the rate of thromboembolic complications was equal for the 2 groups. Low-dose heparin prophylaxis is thus effective and should be given routinely in patients aged over 40 years; it should also be given for more than 1 week in patients not ambulant by then.

Adult↗

PubMed1978