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Biomedical subjects

W Stremmel

Publications and source records attributed to W Stremmel.

At least 271 records · Page 15Linked to original sources
PubMed1984

Hyperinsulinaemia in non-cirrhotic haemochromatosis: impaired hepatic insulin degradation?

This study investigated early alterations of glucose metabolism in idiopathic haemochromatosis. Circulating concentrations of glucose, insulin, C-peptide, glucagon, and gastric inhibitory polypeptide (GIP) were measured after a 100-g oral glucose load in 10 men with idiopathic haemochromatosis in the non-cirrhotic stage of the disease. All had normal glucose tolerance and normal body weight. Ten matched healthy subjects were studied as controls. Insulin concentrations increased to significantly higher levels in patients with idiopathic haemochromatosis than in the control subjects from 30 to 180 min after the glucose load (p less than or equal to 0.01), while fasting insulin concentrations were not significantly different (p greater than 0.05). Concentrations of glucose, glucagon, C-peptide, and GIP were not significantly different at any time (p greater than 0.05). Thus, patients with idiopathic haemochromatosis show hyperinsulinaemia and hence insulin resistance without impaired glucose tolerance in the non-cirrhotic stage. Since pancreatic insulin secretion (C-peptide), glucagon secretion, and the entero-insulinar axis (GIP) are not impaired in these non-cirrhotic patients with idiopathic haemochromatosis, iron accumulation in the hepatocytes may be responsible for the impaired insulin effect and may cause impaired hepatic insulin extraction.

Adult↗
PubMed1984

[Benign recurring intrahepatic cholestasis--a case report].

The diagnosis of benign recurrent intrahepatic cholestasis was made in a 40 year old female. Seven episodes of jaundice persisting up to 6 months in lengths lead to 3 laparotomies, numerous peritoneoscopies and needle biopsies of the liver. Elevation of conjugated serum bilirubin and alkaline phosphatase levels and histopathological confirmation of intrahepatic cholestasis without cholangitis were the main characteristics during the episodes of cholestatic jaundice. However, hepatic histology and liver function were normal in remission periods. Drug induced cholestasis was ruled out by careful history. A sister also suffered from 4 episodes of intrahepatic cholestasis. The etiology of the disease is probably of a genetic origin. The pathogenesis remains unclear. There is no specific treatment to prevent or shorten the occurrence of cholestatic episodes. The patients are advised to avoid pregnancy and oral contraceptives, since both will induce icteric phases.

Adult↗
PubMed1984

[Postoperative complications of the radiation-exposed intestine].

Intestinal complications after radiotherapy cannot be avoided. Side effects of radiotherapy should be differentiated from injuries following correct application of radiation. Acute changes are usually transient. There is only a small incidence of major intestinal radiation injuries, amounting to less than 3%. Exact preoperative diagnostics is advisable in planning corrective operative procedures. The postoperative mortality rate is about 30%, operative procedures must be individualized, staged procedures are recommended.

Humans↗
PubMed1983

Studies of oleate binding to rat liver plasma membranes.

The binding of [14C]oleate to rat liver plasma membranes was examined under various conditions in vitro. In protein free incubation mixtures binding was saturable, inhibited by excess cold oleate, virtually abolished by heat denaturation of the membranes, reversible by post-incubation with cold oleate or albumin, and pH and temperature dependent. When [14C]oleate was incubated in the presence of albumin or beta-lactoglobulin, the amount of membrane bound oleate was a function of the calculated free oleate concentration in the incubation mixture. Trypsin significantly inhibited binding. Further analysis suggests that membranes contain 10(15) high affinity (Kav = 2 x 10(8)M-1) oleate binding sites/mg protein.

Albumins↗
PubMed1983

Studies of albumin binding to rat liver plasma membranes. Implications for the albumin receptor hypothesis.

To characterize a previously proposed hepatocyte albumin receptor, we examined the binding of native and defatted 125I-labeled rat albumin to rat liver plasma membranes. After incubation for 30 min, binding was determined from the distribution of radioactivity between membrane pellet and supernatant following initial centrifugation (15000 X g for 15 min), and after repeated cycles of washing with buffer and re-centrifugation. 125I-labeled albumin recovered in the initial membrane pellet averaged only 4% of that incubated. Moreover, this albumin was only loosely associated with the membrane, as indicated by recovery in the pellet of under 0.5% of the counts after three washes. Binding of 125I-labeled albumin to the plasma membranes was no greater than to erythrocyte ghosts, was not inhibited by excess unlabeled albumin, and was not decreased by heat denaturation of the membranes, all suggestive of a lack of specific binding. Failure to observe albumin binding to the membranes was not due to a rapid dissociation rate or 'off-time', as incubations in the presence of sufficient ultraviolet light to promote covalent binding of ligands to receptors did not increase 125I counts bound to the membrane. Finally, affinity chromatography over albumin/agarose gel of solubilized membrane proteins provided no evidence of a membrane protein with a high affinity for albumin. These studies, therefore, do not support the hypothesis that liver cell plasma membranes contain a specific albumin receptor.

Animals↗
PubMed1983

Physicochemical and immunohistological studies of a sulfobromophthalein- and bilirubin-binding protein from rat liver plasma membranes.

Affinity chromatography over bilirubinagarose and sulfobromophthalein (BSP)-agarose was used to isolate two proteins, with high affinities for bilirubin and BSP, respectively, from Triton X-100-solubilized rat liver plasma membranes. The protein eluted from either affinity column migrated as a single band of approximately 55,000 D on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, and either protein cochromatographed with both [14C]bilirubin and [35S]BSP on Sephadex G-75. On gradient gels without reduction or SDS, or on Sephadex G-150, the native BSP-binding protein had an estimated molecular mass of approximately 100,000 D. After incubation with SDS, an additional Sephadex G-150 peak of molecular mass of 56,000 D was observed. Both, the 100,000- and 56,000-D G-150 peaks cochromatographed with [35S]BSP. The native protein had an isoelectric point of 3.5, stained with periodic acid-Schiff but not Sudan black, and contained 4 mol of sialic acid per mol of protein. A rabbit antibody to the BSP-binding protein gave a line of identity with both the BSP- and bilirubin-binding antigens, and inhibited the binding of [14C]bilirubin and [35S]BSP, but not [14C]oleate or [14C]taurocholate, to rat liver plasma membranes. Immunohistochemical studies revealed the presence of the antigen on all surface domains of rat hepatocytes, but not on other cell populations from normal rat liver. It was not found in other organs. These data are compatible with the hypothesis that a specific liver cell plasma membrane protein mediates the hepatocytic sequestration of bilirubin and BSP.

Animals↗
PubMed1982

A simple procedure for the isolation of bilirubin monoglucuronide and diglucuronide from bile.

Isolation of bilirubin monoglucuronide and diglucuronide from rat and human bile has been accomplished by affinity chromatography over albumin agarose, followed by reverse-phase adsorption chromatography over siliconized kieselguhr. The glucuronide nature of the conjugating saccharide was confirmed by TLC, employing two different solvent systems, of the sugar released by either alkaline hydrolysis or ammonolysis. The bilirubin diglucuronide preparation migrated as a single polar band on direct silica gel TLC, yielded exclusively the delta ethyl anthranilate azopigment, and had a sugar:bile pigment molar ratio of 2.01 +/- 0.03 (S.E.M.). The monoglucuronide migrated as a single, less polar band on TLC, yielded equimolar quantities of alpha and delta azopigments, and had a sugar:bile pigment ratio of 1.02 +/0- 0.04. Both conjugates were preparable in milligram quantities, free of phospholipid, bile acid, and cholesterol, at yields averaging 40% to 60%, and could be isolated with high specific activity by injection of pheonbarbital-penetrated rats with delta-aminolevulinic acid-4- 14C or -2,3-3H. Preparations of pure bilirubin conjugates should greatly facilitate studies of bilirubin metabolism.

Aminolevulinic Acid↗
PubMed1980

[Prophylaxis of gallstone formation (author's transl)].

Today we know the pathobiochemical mechanism of gallstone formation. Cholecystectomy is the therapy of choice with a mortality-rate 0,5% in uncomplicated cases. The mortality-rate increases in patients with recurrent stones in the biliary tract system after cholecystectomy. In addition the liver produces a lithogenic bile. We propose the prophylactic use of chenodesocycholic acid in patients after choledochal revision, if the bile duct system is altered in such a way that cholesterol crystals can aggregate and grow to stones. A low dose of cheno acid is sufficient. Moreover a fibre rich diet increases the chenodesoxycholic acid synthesis in the liver.

Aged↗
PubMed1979

The lipids of the Golgi apparatus subfractions from rat liver.

Golgi apparatus were isolated from untreated rat liver and separated into three fractions. One consisted mainly of vesicles, a second of tubular particles (dictyosomes) and the third was a mixed fraction. Large differences between these fractions could be seen in the electron microscope and by enzyme analysis. The total lipid content of the vesicles was 3.5-times greater than that of the dictyosomes and the neutral lipid value was 7-times greater. The ratio of phospholipids to protein was approximately the same in the three fractions. However, the phospholipid patterns differed between the vesicle and dictyosome fractions.

Animals↗