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Biomedical subjects

W Horak

Publications and source records attributed to W Horak.

At least 37 records · Page 2Linked to original sources
PubMed1979

[Plasmaperfusion through activated charcoal and amberlite XAD-7 in dogs with liver failure induced by yellow phosphorus (author's transl)].

Various sorbents were tested in-vitro for their ability to support hepatic excretory and detoxification functions, and their in-vivo perfusion with plasma was studied in an animal experiment. Amino acids, particularly phenylalanine and tyrosine, were strongest bound by activated charcoal, while Amberlite XAD-7 removed conjugated and unconjugated bilirubin and bile acids from plasma. Using a cell-separator plasma of dogs, in whom acute liver failure was induced by yellow phosphorus, was perfused through a combination of charcoal and Amberlite XAD-7 without major complications. Platelet counts remained nearly unchanged, platelet aggregation was inhibited reversibly, and circulating platelet aggregates occurred late only. It is concluded that using the method described, therapeutic trials in patients with fulminant hepatic failure can be performed.

Animals↗
PubMed1977

[Etiology and clinical aspects of liver cirrhosis].

This review deals with the clinically important aspects of etiology and symptoms of cirrhosis. Apart from alcohol and hepatitis, which are the most frequent etiological factors, also rare causes of cirrhosis are described, because their knowledge is important for the differential diagnosis of cryptogenic cirrhosis. Portal hypertension is the root of most symptoms and complications in cirrhosis. Therefore, a description of the haemodynamic changes precedes the extrahepatic syndromes, of which renal failures, ascites and portal encephalopathy are discussed more in detail.

Alcoholism↗
PubMed1976

Kinetics of [14C]cholic acid in fulminant hepatic failure: a prognostic test.

The kinetics of intravenously injected [14C]cholic acid have been investigated in 14 patients with fulminant hepatic failure, 24 to 36 hr after the development of grade IV encephalopathy. Radioactivity was measured in plasma samples and in the individual plasma bile acid fractions after separation by thin layer chromatography. Plasma disappearance curves of the free [14C]cholic acid were calculated by an iterative nonlinear least squares fitting procedure using a computer. The disappearance of total plasma radioactivity was similar in all patients and greatly prolonged compared with healthy subjects. However, the plasma disappearance of free [14C]cholic acid was significantly faster in the 8 patients who recovered consciousness than in the 6 who did not. Plasma disappearance of free [14C]cholic acid correlated highly significantly with the proportion of conjugated [14C]cholate in plasma. All patients in whom more than 70% of plasma radioactivity was in the conjugated fraction 3 hr after injection survived and left hospital, whereas all of those in whom less than 55% was conjugated died. Measuring the percentage conjugation of [14C]cholate 3 hr after injection may therefore be a useful test of residual liver function in hepatic failure, as a guide to prognosis and in evaluating new forms of treatment.

Adolescent↗
PubMed1975

[Aspects of bile acid metabolism in liver diseases(author's transl)].

Although chemistry and physiology of bile acids have been elucidated during the last two decades, tests concerning bile acid metabolism are still rarely used in clinical medicine. The aim of this study therefore was, to investigate bile acid metabolism in patients with liver diseases and to find prognostic valuable parameters which can be recommended for clinical use. Following an introducing review of biosynthesis and kinetics of bile acids, normal values are presented for pool size and synthesis of the two primary bile acids, for bile lipid composition, plasma bile acid concentration and for clearance and conjugation of intravenously injected 14C-cholic acid, which have been measured in healthy subjects. Bile acids were determined by thin-layer-chromatography, gas-liquid-chromatography and by an enzymatic and fluorimetric method. In all patients investigated with acute hepatic necrosis, plasma disappearance of radioactivity was greatly prolonged after intravenous injection of 14C-cholic acid. By estimating free 14C-cholic acid and 14C-cholic acid conjugates in plasma individually, two groups of patients could be distinguished: in patients who survived hepatic coma, the clearance of free 14C-cholic acid was significantly more rapid and the percentage of glycine and taurine conjugates of 14C-cholic acid in plasma was significantly higher than in patients who died in coma. This prognostic significant differentiation was possible by measuring the relationship of conjugated: unconjugated radioactivity in one single plasma sample taken three hours after injection. In patients with cirrhosis of the liver the plasma disappearance rate of radioactivity during 60 minutes following injection of 14C-cholic acid was significantly correlated with serum-bilirubin, SGOT, serum-albumin, prothrombine-time, plasma bile acids, and a clinical scoring. 14C-deoxycholic acid was found in plasma of only a few patients 24 hours after injection of the labelled cholic acid, and was related to the relatively good liver function in these patients. It is concluded that the following tests of bile acid metabolism are of clinical interest: 1. Measuring plasma bile acid concentration may serve as a sensitive liver function test. 2. Estimation of the conjugation of intravenously injected 14C-cholic acid is of prognostic value in patients with fulminant hepatic failure. 3. Determination of the initial plasma disappearance rate of 14C-cholic acid injected intravenously and its transformation to 14C-cholic acid injected intravenously and its transformation to 14C-deoxycholic acid may help to classify patients with cirrhosis of the liver.

Adolescent↗
PubMed1975

Effect of portacaval shunt and arterialization of the liver on bile acid metabolism.

The effect on bile acid clearance of portacaval end-to-side shunt, with and without arterialization of the hepatic portal venous bed, was studied in dogs. Portacaval shunt reduced liver blood flow by 75%, and peripheral serum bile acid concentration rose from 3 to 239 muM. Arterialization maintained total liver blood flow within physiological range and serum bile acid concentration was only 19 muM. Since hepatic bile acid extraction was similar in both groups, bile acid clearance was determined largely by total liver blood flow. The results of this study indicate that hepatic clearance of substances originating from portal blood is impaired in portacaval shunt and can be restored by increasing the arterial blood supply to the liver.

Ammonia↗
PubMed1975

[Kinetics of bile acid in jejuno-ileal bypass].

The influence of jejunoileal bypass on bile salt kinetics and lithogenity of bile was investigated in 9 German shephard dogs. Total bile acid pool decreased 92% from initial values, bile acid turnover rate was enhanced markedly. High relative biliary cholesterol concentration lead to an increase of lithogenity of the bile.

Animals↗
PubMed1975

[Physiology of bile secretion].

Canalicular bile secreted by the hepatocyte consists of at least two fractions: one is initiated by active transport of bile acids, the other is due to active transport of inorganic ions. Bilirubin and other organic anions, organic cations, and neutral compounds are secreted into the canalicular bile as well as lecithin and cholesterol. Subsequently the biliary tree, the gallbladder, and the enterohepatic circulation of bile acids have an effect on bile formation. Choleresis induced by drugs may be due to a direct osmotic effect of the compound secreted in bile or to an increase of the bile acid independent fraction of bile flow. Cholestasis frequently is caused by inhibition of the bile acid independent fraction. Studies on micellar solubility of cholesterol have led to new concepts concerning formation of cholesterol gallstones and their dissolution with chenodeoxycholic-acid therapy.

Amiloride↗