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Biomedical subjects

R Arnold

Publications and source records attributed to R Arnold.

At least 343 records · Page 19Linked to original sources
PubMed1990

[The coincidence of acute intermittent porphyria and Crohn's disease].

In the course of four weeks, tetraparesis developed in a 28-year-old man with Crohn's disease for the last six years, treated with glucocorticoids and sulphasalazine. The cause was acute intermittent porphyria which had been previously overlooked because of the similar abdominal symptoms of Crohn's disease. Treatment with glucose, propranolol and haemarginate failed to bring about any improvement, but there was a remission of the porphyria. This case demonstrates that diagnosis of acute intermittent porphyria in the presence of Crohn's disease is difficult, and if delayed therapeutic measures in the face of persisting neurological complications are of little benefit.

Acute Disease↗
PubMed1990

Islet amyloid polypeptide (IAPP;amylin) influences the endocrine but not the exocrine rat pancreas.

The effect of synthetic rat amylin (10,100,1000 pmol/l) on glucose (10 mmol/) and arginine (10 mmol/l) -stimulated islet hormone release from the isolated perfused rat pancreas and on amylase release from isolated pancreatic acini was investigated. Amylin stimulated the insulin release during the first (+76%) and the second secretion period (+42%) at 1 nmol/l. The first phase of the glucagon release was inhibited concentration dependently by amylin and completely suppressed during the second phase. Amylin diminished the somatostatin release in a concentration dependent manner. This effect was more pronounced at the first than the second secretion period (1 nmol amylin: 1 phase: -60%, 2.phase: -22%). Amylin was without any effect on basal and CCK stimulated amylase release from isolated rat pancreatic acini. Our data suggest amylin, a secretory product of pancreatic B-cells, as a peptide with approximately strong paracrine effects within the Langerhans islet. Therefore, amylin might be involved in the regulation of glucose homeostasis.

Amylases↗
PubMed1990

Cosecretion of amylin and insulin from isolated rat pancreas.

Amylin, a 37 amino acid C-terminal amidated peptide is an integral part of secretory granules of pancreatic beta-cells. Utilizing a specific radioimmunoassay system we demonstrate in the present study a cosecretion of amylin and insulin from the isolated rat pancreas. The secretion pattern of both peptides during glucose or glucose plus arginine stimulation is identical. The molar ratio of amylin amounts to 10% of that of insulin. The biological significance of amylin is still unknown, but a paracrine/endocrine role in glucose homeostasis is speculated.

Amyloid↗
PubMed1990

Atrial natriuretic factor has a weak insulinotropic action in the isolated perfused rat pancreas.

The effect of atrial natriuretic factor (ANF; 1, 10, 100, 1000 pmol/l) on insulin release from the isolated perfused rat pancreas was studied. ANF weakly augmented the glucose (10 mmol/l)-stimulated insulin release during the second (controls: 100%; 1 pmol/l: 99%; 10 pmol/l: 149%, P less than 0.05; 100 pmol/l: 111%; 1000 pmol/l 135%), but not the first phase of the secretory response. In contrast, the first, but not the second phase of arginine (10 mmol/l)-stimulated insulin release was significantly enhanced by ANF (1000 pmol/l; controls: 100%; 1000 pmol/l: 235%, P less than 0.05). The hormone did not influence basal insulin secretion. Our data indicate an insulinotropic effect of ANF on the rat pancreas, which is dependent on the utilized background secretagogues.

Animals↗
PubMed1990

Structural alterations of pancreatic microvasculature in cerulein-induced pancreatitis in the rat.

Pancreatic microvasculature in cerulein-induced pancreatitis was studied at the electron and light microscopic level. Using a modified model of in situ india ink perfusion, focally a marked reduction of the number of india-ink-filled microvessels was found. The numerical density (NA) of filled microvessels was reduced by 66.7% in pancreatitis. The morphological correlate for this extreme numeric reduction might be a collapse of the lumen of pancreatic microvessels. In the presence of cerulein pancreatitis 42% of pancreatic capillaries had a collapsed lumen as shown by electron microscopy. The endothelium of capillaries in acute pancreatitis demonstrated surface blebbing, the formation of cytoplasmatic vacuoles, edema, and swollen mitochondria. Some capillaries had irregularities at the interendothelial junction, and the majority of examined vessels were surrounded by marked perivascular edema. No strict correspondence between histological signs of pancreatitis and light microscopic and/or ultrastructural microvascular alterations could be demonstrated. Our study emphasizes that alterations of microvasculature are present early in experimental edematous pancreatitis. Therefore, alterations of pancreatic microcirculation seem to be of great importance in the pathogenesis of pancreatic inflammation, and should be the subject of further studies.

Animals↗
PubMed1990

Cerulein-induced acute pancreatitis in rats: evidence for reduced calcium affinity of secretory granule membranes.

Membranes of secretory granules in pancreatic acinar cells seem to be interrelated in the regulation of intragranule Ca2+ concentrations. Since low intragranule Ca2+ levels are involved in zymogen stabilization versus autoactivation of proteases, a disturbance of the Ca2(+)-regulating system in secretory granules could be invoked to account for uncontrolled proenzyme activation. This is proposed as the initial mechanism in the pathogenesis of acute pancreatitis. Using pancreatic subcellular fractions obtained from control rats and after induction of acute cerulein pancreatitis we found a markedly reduced Ca2+ affinity of membranes from the secretory granule fraction in pancreatitis. The strong Ca2+ binding of control zymogen granule membranes primarily seemed to be a function of non-proteinacous membrane components, e.g. phosphatidylinositols. It is suggested, that part of the inner surface of membranes from secretory granules acts as a calcium-buffering system that works in synergy with other protective mechanisms to stabilize the zymogen granule population. In cerulein pancreatitis there seemed to be an imbalance of this system.

Animals↗
PubMed1990

Volume and enzyme kinetics of human pancreatic secretion after endogenous stimulation with the Lundh test meal.

The present study was undertaken to investigate the volume and enzyme kinetics of human pancreatic secretion, after endogenous stimulation with a Lundh test meal, and evaluate the most reliable enzyme and collection period. The prestimulatory volume rates did not differentiate normal from pathologic pancreatic function. After ingestion of the test meal, the immediate increase in volume secretion was identical in healthy subjects and patients with pancreatic insufficiency. The latter showed a drastic reduction of prestimulatory and postprandial enzyme secretion. Cimetidine taken orally 12 and 2 h before the test meal study had no effect on volume and enzyme secretion and endogenous CCK release. Especially in severe pancreatic insufficiency, this modification simplified the performance of the Lundh test. The estimation of lipase and trypsin gave a significant correlation between Lundh test and secretin-cerulein test. The endogenous stimulation by Lundh test meal is a reliable test for routine diagnostic and scientific purposes.

Adult↗
PubMed1990

The effects of two FMRFamide related peptides (A-18-F-amide and F-8-F-amide; 'morphine modulating peptides') on the endocrine and exocrine rat pancreas.

The effects of two recently isolated mammalian FMRFamide related peptides (A-18-F-amide and F-8-F-amide) on the encocrine and exocrine rat pancreas were investigated. A-18-F-amide (10, 100, 1000 pM) inhibited concentration dependently glucose (10 mM)- and arginine (10 mM)-induced insulin secretion from the isolated perfused rat pancreas during the first (controls: 100%; 10 pM: 114%; 100 pM: 63%, p less than 0.05; 1000 pM: 31%, p less than 0.05) and the second secretion phase (controls: 100%; 10 pM: 102%; 100 pM: 78%; 1000 pM: 27%, p less than 0.05). The inhibitory actions of A-18-F-amide on pancreatic D-cell secretion were more pronounced during the first than the second phase (first phase: controls: 100%; 10 pM: 95%; 100 pM: 37%, p less than 0.05; 1000 pM: 39%, p less than 0.05%; second phase: controls: 100%; 10 pM: 113%; 100 pM: 72%; 1000 pM: 59%, p less than 0.05). F-8-F-amide (at 1000 pM) inhibited stimulated insulin (controls: 100%; first phase: 26%, p less than 0.05%; second phase: 20%, p less than 0.05) and somatostatin release (controls: 100%; first phase: 14%, p less than 0.05; second phase: 29%, p less than 0.05). Both peptides were without effect on basal and CCK-8-stimulated amylase release from isolated incubated rat pancreatic acini.

Amino Acid Sequence↗
PubMed1990

Determinants of survival following repair of interrupted aortic arch in infancy.

Between January 1971 and March 1987, surgery was performed in 26 infants with interrupted aortic arch. At operation the 14 boys and 12 girls weighted between 1.71 and 4.23 kg (mean +/- SD = 3.1 +/- 0.63 kg) and ranged in age from 2 to 90 days (13 +/- 18 days). The interruption was distal to the left subclavian artery in 4 (15%), between the left carotid and subclavian arteries in 20 (77%) and between the brachiocephalic (innominate) and left carotid arteries in 2 (8%). Associated complex cardiac lesions in 8 patients included complete transposition (2), common arterial trunk (2), aortopulmonary window (2), double inlet left ventricle (1) and tricuspid atresia (1). The remaining patients had an isolated ventricular septal defect. The arch was reconstructed with a prosthetic conduit in 14 patients; by a direct anastomosis in 6; using the subclavian artery in 3; and with the pulmonary trunk and the arterial duct in 2. Twenty patients (77%) underwent palliative surgery as the first stage of management, and banding of the pulmonary trunk was also performed in 16 of these. Five patients (19%) underwent primary complete repair of the interruption and intracardiac anomalies. One patient (4%) died soon after thoracotomy for palliative surgery. Of the 15 (57%, 70% confidence limits CL = 46-69%) early deaths, 7 occurred in patients with complex associated defects and 4 occurred when single stage repair was attempted. Survival following first-stage palliative surgery for arch interruption with isolated ventricular septal defect was 64% (9/14) [70% CL = 47-79%]. All of these patients subsequently underwent complete repair. Chi-squared and t-tests showed the year of operation and the type of operation (two-stage repair) to be associated with improved survival. It is concluded that a two-stage repair of interrupted aortic arch offers a reasonable alternative to primary complete correction and will lead to satisfactory subsequent repair in most cases.

Anastomosis, Surgical↗
PubMed1990

The cardiovascular response to exercise in the patient with congestive heart failure.

Individuals with moderate to severe heart failure may benefit from cardiac fitness training. However, before recommending cardiac rehabilitation to this patient population, nurses must understand exercise physiology and the effects of exercise in the individual with chronic left ventricular dysfunction (LVD). Normal cellular response to exercise, normal cardiovascular responses associated with exercise, cardiovascular adaptation to exercise training or conditioning, cardiovascular responses to exercise in patients with LVD, and cardiac rehabilitation of the patient with chronic congestive heart failure are addressed in this article. Responses to isotonic exercise, rather than isometric, are emphasized.

Exercise↗
PubMed1990

Resolution of human exocrine pancreatic juice proteins by reversed-phase high performance liquid chromatography (HPLC).

Exocrine proteins contained in human pancreatic juice were analyzed by reversed-phase high performance liquid chromatography (RP-HPLC). Pancreatic juice was saved by endoscopic retrograde cannulation of the main pancreatic duct in 17 persons: 12 without pancreatic disease, 3 patients suffering from recurrent acute pancreatitis probably due to pancreas divisum, 1 patient with a carcinoma of the pancreas, and 1 patient with chronic calcified pancreatitis. The juice proteins were separated on a silica column (Nucleosil 300-7 RP) by use of a multistep acetonitrile/water gradient (+0.1% trifluoroacetic acid). Up to 18 individual peaks could be separated by one analytical run (60 min). Molecular weight analysis by sodium dodecyl sulfate-gel electrophoresis indicated the presence of enzymes such as amylase, prophospholipase A2, procarboxypeptidases, trypsinogens, and chymotrypsinogens in certain peaks. Small residual enzymatic activities correlating with certain peaks were detected for amylase and chymotrypsin, and high residual activities were found for phospholipase A (recovery of enzymatic activity compared with the original sample amounted to 65%). Significant amounts of cathodic trypsin-like immunoreactivity were found in two certain peaks. By always loading 350 micrograms of protein/injection on the column the profiles of various samples showed similar patterns. Repeated injections of aliquots revealed highly reproducible profiles. RP-HPLC offers precise, reproducible, and rapid separation of the major proteins of human pancreatic juice.

Chromatography, High Pressure Liquid↗
PubMed1990

Interaction of glucagon-like peptide-1 (7-36)amide and cholecystokinin-8 in the endocrine and exocrine rat pancreas.

The synergistic impact of glucagon-like peptide-1 (GLP-1) (7-36)amide and cholecystokinin-8 (CCK-8) was studied in the rat pancreas. The GLP-1 (7-36)amide (1 pM-1 microM) had no effect on the basal or CCK-stimulated (1 nM-1 pM) amylase release from isolated pancreatic acini. The insulinotropic action of 0.5 nM GLP-1 (7-36)amide, which weakly stimulated the glucose-induced (6.7 mM) insulin release from the isolated perfused rat pancreas, was strongly potentiated by the addition of CCK-8 (20, 50, and 100 pM) to the perfusate. In concentrations as they occur physiologically after a meal, CCK-8 alone had no significant effect on basal or glucose-stimulated (6.7 mM) insulin secretion. Our data support the assumption that the nutrient-regulated intestinal release of various peptides represents a regulatory system to ensure an adequate insulin response to food intake, at least in rats.

Amylases↗
PubMed1990

Serum gastrin levels during long-term omeprazole treatment.

Serum gastrin was determined in 33 patients during treatment with the proton pump inhibitor omeprazole. After 4 weeks of therapy, gastrin levels increased to a median of 55 pg/ml compared to 15 pg/ml prior to omeprazole (P less than 0.001). There was a close correlation (r = 0.939; P less than 0.001) between pre-treatment gastrin and levels at 4 weeks. Comparison of serum gastrin concentrations at 1 month of omeprazole with levels at 6 (n = 21) and 12 months (n = 12) continuous therapy revealed a close correlation (r = 0.961 and r = 0.882, respectively; P less than 0.001) despite dose adjustment. In marked hypochlorhydria documented by continuous pH monitoring, serum gastrin varied from normal up to profound hypergastrinaemia. These results demonstrate that the serum gastrin increase under powerful acid-inhibitory drug therapy depends upon a number of variables. (a) Only in patients with elevated gastrin levels, prior to omeprazole treatment, can moderate to marked hypergastrinaemia during omeprazole be expected. (b) Gastrin increases reached during the initial period of omeprazole treatment remain constant during long-term therapy. (c) Acid inhibition itself is not necessarily associated with an increase in serum gastrin in every patient, which suggests that the individual sensitivity of the gastrin cell to acid inhibition is more important for serum gastrin changes than the degree of acid inhibition itself.

Esophagitis, Peptic↗
PubMed1990

Prospective evaluation of omeprazole treatment in reflux oesophagitis refractory to H2-receptor antagonists.

The efficacy of omeprazole therapy (40 mg daily) in H2-blocker refractory severe reflux oesophagitis (Grade II-IV; Savary and Miller classification) was investigated in 61 patients. Mean duration of reflux disease and preceding H2-antagonist treatment were 4.3 years and 15 months, respectively. Healing rates at 4, 8 and 12 weeks were 48%, 80% and 92%, respectively. There was a correlation between severity of oesophagitis and duration of omeprazole therapy necessary for healing. Three patients (5%) required higher dosages than 40 mg for healing. Symptomatic responses paralleled healing. It is concluded that omeprazole is a highly effective drug for severe reflux oesophagitis not responding to H2-blocker treatment and that 40 mg daily is the optimal dose.

Adolescent↗
PubMed1990

Therapeutic strategies in the management of endocrine GEP tumours.

The therapeutic principles in the management of endocrine gastroenteropancreatic (GEP) tumours include surgical extirpation of the primary tumour in the absence of metastases and medical control of symptoms in the preoperative phase. In the presence of metastases only palliative procedures are available. Tumour growth might be controlled by surgical procedures as debulking of tumour masses, medically by chemotherapy and more recently by new developments as a long-acting somatostatin analogue (SMS 201-995) and alpha-interferon. Their efficacy is currently evaluated in prospective studies. In contrast to inhibition of growth symptoms derived from excessive hormone production by GEP tumours can be well controlled. SMS 201-995 effectively prevents or at least improves flush and diarrhoea in the carcinoid syndrome, disabling diarrhoea in the Verner-Morrison syndrome and migratory erythema in the glucagonoma syndrome. SMS acts by inhibition of hormone release from the tumour and by a direct mechanism at the site of the target cell via SMS receptors present on tumour and target cells. For control of acid hypersecretion in gastrinoma patients omeprazole is superior to all former and present alternatives and replaced total gastrectomy completely. A similarly effective drug to prevent hypoglycaemia due to uncontrolled insulin release from insulinomas is not available since neither SMS nor diazoxide are effective in every insulinoma patient.

Amino Acid Sequence↗
PubMed1990

Doppler echocardiographic evaluation of pulmonary artery flow after modified Fontan operation: importance of atrial contraction.

Doppler echocardiography was used to evaluate blood flow in the pulmonary artery in 14 patients 2 to 42 months (mean (SD) 17 (12) months) after a modified Fontan operation incorporating a direct atriopulmonary anastomosis. Preoperatively six patients had tricuspid atresia, six had a double inlet left ventricle, and two had pulmonary atresia with an intact ventricular septum. The postoperative rhythm was sinus in 11 patients, junctional in one, ventricular pacing in one, and atrioventricular sequential pacing in one. In one patient the Doppler trace was unsatisfactory for analysis. In all patients forward flow in the pulmonary artery had biphasic peaks related to both atrial and ventricular contraction. The mean (SD) peak flow velocity that was synchronous with atrial contraction was 80 (30) cm/s and that synchronous with ventricular contraction was 74 (23) cm/s. The atrial contribution to total pulmonary artery flow, assessed by velocity-time integrals, varied between 22% and 73% (mean (SD) 45 (14)%). In patients with tricuspid atresia the mean (SD) peak flow velocity with atrial contraction was 90 (27) cm/s and that with ventricular contraction was mean (SD) 68 (24) cm/s. In patients with double inlet left ventricle the mean (SD) peak flow velocity was 67 (36) cm/s with atrial contraction and 80 (25) cm/s with ventricular contraction. The atrial contribution to total pulmonary blood flow in patients with tricuspid atresia was significantly higher (53 (11)%) than in those with double inlet left ventricle (37 (14)%). Pulmonary artery flow after modified Fontan operation was biphasic and was related to both atrial and ventricular contraction. The atrial contribution to pulmonary blood flow is greater in patients with tricuspid atresia than in those with a double inlet left ventricle. The mechanism of the second peak related to ventricular contraction is unknown.

Adolescent↗