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Biomedical subjects

W Dummler

Publications and source records attributed to W Dummler.

At least 19 recordsLinked to original sources
PubMed1992

[Correlation between acinar cell fat accumulation and secretory capacity of the rat pancreas in the early stage of alcohol-induced pancreatopathy].

In patients exhibiting chronic alcohol abuse, the accumulation of fat droplets in pancreatic acinar cells, as well as changes in pancreatic secretion, can be interpreted as early signs of pancreatic damage. Using rats, (the animals were fed for 9 +/- 1 months with a solution of 20% v/v ethanol, combined with either a normal or a fat enhanced diet) we tested whether or not these symptoms are related both to each other and to morphological lesions of the tissue. Based on six separate histological criteria, the lesions were classified into five stages of severity. In order to characterize the secretory capacity of the pancreas, we measured the outputs of lipase, alpha-amylase, trypsin, chymotrypsin, carboxypeptidase A, elastase, and phospholipase A. Compared with the control group, we found that the alcohol-fed animals exhibited a significantly higher degree of morphological damage to the pancreas, as well as an increased frequency of fat accumulation in the acinar cells, and, with the exception of alpha-amylase, a rise in the level of enzyme secretion. In the animals exhibiting the highest degree of tissue damage, however, both fat accumulation and hypersecretion appeared to be diminished. This diminution could possibly be interpreted as the first sign of chronic pancreatitis. Increased consumption of fat did not change either the level of fat accumulation in the acinar cells, or the level of pancreatic secretion. Within the group of alcohol-fed rats, the most pronounced levels of hypersection were found in animals exhibiting cellular fat accumulation. However, the secretion levels of the alcohol-fed animals exhibiting no such fat accumulation did not differ significantly from that of the control group. Therefore, a relationship appears to exist in rats between fat accumulation in acinar cells and the level of pancreatic secretion.

Adipose Tissue↗
PubMed1990

Encapsulation of liver microsomes--a further procedure for detoxication.

Due to their partial permeability and their good mechanical properties, the symplex capsules are technically suited for an application in extracorporal detoxification. By this newly developed procedure the activity of encapsulated enzymes is considerably increased; thus, application for extracorporal detoxification seems to be advisable.

Animals↗
PubMed1990

[An improved method for the microencapsulation of liver microsomes for use in extracorporeal detoxication].

Rat liver microsomes were microencapsulated in a pure aqueous medium by means of a new technique. The wall of the microcapsules consists of a semipermeable simplex membrane which is stabilized mainly by electrostatic interactions between a polymeric polyanion (sodium cellulose sulphate) and a polymeric polycation (polydimethyldiallylammonium chloride). The metabolic as well as the mechanic parameters of the microcapsules could be markedly improved by separating the metabolic (liver microsomes) from the membrane component (sodium cellulose sulphate) in such a way that two distinct compartments are formed during the preparation of the microcapsules.

Animals↗
PubMed1990

[Lymph drainage disorder as a pathogenetic co-factor in acute pancreatitis?].

Experiments performed on 71 Wistar rats confirm that preexisting interruption of lymph drainage by ligation of the ductus thoracicus can have a major influence on the development of pancreatitis. The effect of a ductus hepatopancreaticus blockade in experimental group A (32 animals) was greatly exacerbated by previous ligation of the ductus thoracicus (experimental group B; 34 animals). Edema of the interstitial pancreatic tissue led to lipolytic necrotizing pancreatitis with a slight hemorrhagic component, increasing ascites after the 12 th hour of the experiment, and numerous abdominal fat necroses after about 19 hours, but only relatively minor necroses of acinar parenchyma cells in the pancreas. Fat tissue necroses were only found in almost 20% of the animals in group A, and these probably resulted from manipulation of the duodenum during the implantation of a shunt to divert the bile, whereas they were found in all animals of group B after the 19th hour of the experiment, usually in large numbers. The sometimes considerable increases in serum amylase and particularly lipase activity were caused by obstruction of the efferent ducts, but did not increase appreciably after disturbance of the lymph drainage systems. On the contrary, under these circumstances, drainage of the salivary edema via the peritoneal mesothelium and into retroperitoneal fat tissue must be considered responsible for ascites and the initiation of fat cell necroses by lipase and other enzymes.

Acute Disease↗
PubMed1990

[Enzymatic determination of glandular kallikrein in human pancreatic secretions].

A method for the enzymatic determination of tissue kallikrein (EC 3.4. 21.8) in human pancreatic juice using D-Val-cyclohexyl-Ala-Arg-4-nitroaniline as substrate as well as the reaction conditions optimized for 37 degrees C are described. The reaction is characterized by the following kinetic parameters, determined according to Hanes and Eisenthal, Cornish-Bowden: KM = 2.10(-5) mol/l; Vmax = 0.800 mumol/(l.s). The coefficient of intra-assay variation (N = 10) was determined to 2.54%. The detection limit of the assay was found to be 8.63 nmol/(l.s).

Clinical Enzyme Tests↗
PubMed1989

[The determination of trypsin activity in duodenal fluid with N alpha-(p-toluenesulfonyl)-L-arginine-p-nitranilide (L-TAPA)].

The conditions are optimized for the determination of trypsin activity in duodenal juice at 37 degrees C using L-TAPA as a substrate ("Bio-La-Test Trypsin", Lachema, CSSR). Most of the directions of the kit could be accepted, but optimal pH was 0.4 units below that described there. This method allows a highly specific, sensitive, and sufficiently precise determination of trypsin activity in duodenal juice.

Anilides↗
PubMed1989

[Comparative observations of internal and external quality controls in the districts of Neubrandenburg and Rostock].

A useful combination of results from internal quality control and external quality assessment is possible only if the statistical procedures of both systems involve the same limits to accept control data. These limits are shown. For 45 laboratories expected quality groups QG-T are calculated from results of internal quality control. Quality groups QG-RVL are calculated from results of external quality control assessment. In 30 cases the great difference of QG-T and QG-RVL is supposed to be caused by inaccurate performance of internal quality control.

Germany, East↗
PubMed1988

Significance of disturbed lymph flow for the pathogenesis of pancreatitis. I. Ligature of the ductus thoracicus in the rat.

To examine the significance of a disturbed lymph drainage for the pathogenesis of acute necrotizing pancreatitis, thoracic duct ligation was performed in 53 Wistar rats. Histological examination of the pancreas and analysis of serum lipase and serum amylase were carried out at various time intervals from 1 h to 42 days after initiating the experiment. Sudden stop of the lymph flow induced a long lasting pancreatic edema, initially in the perilobular interstitium and eventually also within some lobules, with scattered necroses of whole acini or single acinar cells mainly in the peripheral zones of the lobuli. In addition, a marked interstitial inflammatory infiltrate developed, resembling lipophage granulomas. This was most likely due to alymphangeal reflux of sunflower oil, applicated for the visualization of the thoracic duct. These findings suggest that changes in the lymph flow may favour the development of acute necrotizing pancreatitis.

Amylases↗
PubMed1988

[The pH dependence of lipase and trypsin activity].

We investigated in-vitro the relation of the lipase and trypsin activity, containing in native duodenale juice, to pH-values, similar to them registered in the duodenum of patients with severe exocrine insufficiency. Therefore week alcaline duodenal juice was acidified by native gastric juice or hydrochloric acid to pH-value 7, 6, 5 und 4. The remaining activity was estimated after 5, 10, 15 and 20 minutes. We determined a fast inactivation of lipase at pH 5.0 or below (incubation of 5 minutes only decreased the activity to 35% of origin), and of trypsin at pH 4.0 or below (incubation of 5 minutes at this pH-value decreased the activity to 26% of origin). According to the denaturating effect on the enzymes, there was no difference between gastric juice and hypochloric acid. It is concluded, that the activity of decreased secreted pancreatic enzymes in severe exocrine pancreatic insufficiency and also of the oral substituted enzymes is additionally reduced by acidic duodenal circumstances, so that a gastric acid neutralizing or inhibiting therapy proves as necessary.

Duodenum↗
PubMed1987

[Studies of pure human pancreatic juice].

The test-combination from Fa. Boehringer Mannheim GmbH for measuring citric acid present in foodstuffs is also suitable for use in human pancreatic juice. Accuracy, within-run and between-day imprecision are satisfactory. The detection limit of the method is at least 10 mumol citrate/l pancreatic juice. The limit can be reduced when exact additions of citrate are given to the pancreatic juice and then evaluated using regression analysis. The presence of Ca-ions and possibly also trypsin in the material to be tested does not interfere with the reaction. It is, however, necessary to remove proteins from the sample. Deproteinization can be performed either by ultrafiltration or with perchloric acid.

Cholecystokinin↗
PubMed1986

[Biochemical diagnosis of duodenitis].

The activities of enteropeptidase, alanine aminopeptidase, sucrase, and leucine aminopeptidase were determined in mucosa biopsies taken from three defined places of the duodenum and in duodenal juice. We examined 23 adults with a histological proven normal mucosa and 10 patients suffering from duodenitis grade I. Using multivariate evaluation of all the four enzyme activities of the three mucosa sites, we could differentiate duodenitis from normal mucosa with an efficiency of 88%.

Adult↗