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Biomedical subjects

A Stiehl

Publications and source records attributed to A Stiehl.

At least 73 records · Page 4Linked to original sources
PubMed1991

Biliary secretion of bile acids, lipids, and bilirubin by the transplanted liver. A quantitative study in patients on cyclosporine.

To investigate biliary secretion in liver-transplanted patients on cyclosporine treatment we used duodenal perfusion with a nonabsorbable marker. After an overnight fast, 4 women and 5 men were studied for 6 hr at least 6 weeks after orthotopic liver transplantation. The data were compared with those obtained in 6 healthy controls. All transplanted patients received immunosuppressive therapy (corticosteroids, azathioprine, and cyclosporine). Biliary secretion rates of healthy controls were: bile acids 1.58 +/- 0.67 mmol/hr, phospholipids 0.27 +/- 0.11 mmol/hr, cholesterol 0.11 +/- 0.01 mmol/hr, and bilirubin 18 +/- 0.7 mumol/hr (mean +/- SEM). Liver-transplanted patients excreted 2.60 +/- 0.4 mmol/hr bile acids, 0.56 +/- 0.08 mmol/hr phospholipids, 0.18 +/- 0.04 mmol/hr cholesterol, and 22.0 +/- 4.5 mumol/hr bilirubin. Analysis of individual bile acids revealed that in the bile of liver transplant patients the percentage of cholic acid was elevated, whereas that of deoxycholic acid was reduced as compared with controls. These findings indicate that in the transplanted liver under immunosuppressive therapy with cyclosporine biliary secretion of bile acids, lipids, and bilirubin is not reduced.

Adult↗
PubMed1990

Biliary excretion of iron in healthy man and in patients with alcoholic cirrhosis of the liver.

We measured the biliary excretion of iron in 11 patients with alcoholic cirrhosis of the liver and in 10 healthy controls using an intestinal perfusion technique. In the patients with cirrhosis increased amounts of iron in liver tissue were present. The concentrations of iron in the bile samples were determined by atomic absorption spectrometry. The biliary excretion of iron in the healthy controls was 0.32 +/- 0.09 mumol/h and in the patients with cirrhosis it was 0.45 +/- 0.14 mumol/h. The biliary excretion of iron in the patients with cirrhosis was not reduced, indicating that other mechanisms than a reduced biliary excretion of iron must be responsible for the accumulation of iron in liver tissue in alcoholic cirrhosis.

Adult↗
PubMed1990

Ursodeoxycholate reduces hepatotoxicity of bile salts in primary human hepatocytes.

Primary human hepatocytes were used to study bile salt hepatotoxicity and the hepatoprotective potential of ursodeoxycholate in vitro. Hepatocytes were obtained by collagenase perfusion of healthy human liver tissue and were treated with glycochenodeoxycholate for 24 hr 1 day after plating. Clear signs of cytotoxicity were observed at concentrations of about 100 mumol/L glycochenodeoxycholate. Toxicity was determined by release of alkaline phosphatase, gamma-glutamyl transferase, AST, ALT or lactate dehydrogenase into the culture medium, by measuring DNA synthesis of the cultured liver cells and by testing the viability of the hepatocytes using trypan-blue dye exclusion. Addition of ursodeoxycholate, which by itself proved to be of little toxicity, significantly reduced the hepatotoxic effects of glycochenodeoxycholate: 72% +/- 6% of the cells survived treatment with 500 mumol/L glycochenodeoxycholate alone, but addition of 100 mumol/L ursodeoxycholate increased the survival rate to 87% +/- 4% (p less than 0.05). Moreover, all enzymes tested were secreted at a significantly lower level when ursodeoxycholate was present. Similarly, the cellular DNA synthesis was maintained at significantly higher levels as a result of ursodeoxycholate treatment. We conclude that (a) primary human hepatocytes are a suitable model for studying hepatotoxicity of bile salts in vitro, (b) ursodeoxycholate reduces hepatotoxicity of other bile salts and (c) ursodeoxycholate can act hepatoprotectively by itself (i.e., alteration of the metabolism of other bile salts is not necessarily required).

Bile Acids and Salts↗
PubMed1990

Ursodeoxycholic acid-induced changes of plasma and urinary bile acids in patients with primary biliary cirrhosis.

Ursodeoxycholic acid treatment of patients with primary biliary cirrhosis may lead to relief of pruritus and improvement of biochemical liver tests. The changes in serum and urinary bile acids induced by ursodeoxycholic acid treatment were studied. After 29 patients with primary biliary cirrhosis were treated with ursodeoxycholic acid (750 to 1,000 mg/day) for 6 to 12 mo because of an increase in ursodeoxycholic acid, total plasma bile acids increased from 30.5 +/- 6 mumol/L (mean +/- S.E.M.) to 52.7 +/- 11.7 mumol/L (p less than 0.01). The increase in total plasma bile acids correlated significantly with concentrations of plasma bile acid before treatment (p less than 0.01). The concentrations of endogenous bile acids decreased, mainly because of a decrease of cholic acid. During treatment, glycine conjugation increased and taurine conjugation decreased, whereas sulfation and glucuronidation of bile acids were unchanged. In 10 patients with primary biliary cirrhosis in stages III and IV, urinary excretion of bile acids was also studied. After treatment, ursodeoxycholic acid and its 3-beta isomer and C-1-hydroxylated and C-6-hydroxylated derivatives were also excreted. During treatment, urinary excretion of endogenous bile acids decreased. The increase of ursodeoxycholic acid and the decrease of endogenous bile acids may both be related to the improvement of biochemical liver tests in precirrhotic stages of the disease. In cirrhosis, endogenous bile acids in plasma remained high and changes in liver tests were small.

Bile Acids and Salts↗
PubMed1990

Transport of chenodeoxycholic acid and its 3-alpha- and 7-alpha-sulfates by isolated perfused rat liver.

In patients with cholestasis, levels of sulfated bile acids rise. Sulfate esters of chenodeoxycholic acid are the most abundant of these bile acid sulfates. These compounds are taken up by the liver and excreted into bile, although their plasma clearance and biliary excretion are reduced compared with that of unsulfated bile acids. It is not clear whether this is due to differences in intrinsic hepatic uptake or biliary excretion. In the present study, single-pass transport kinetics of chenodeoxycholic acid 3-alpha-sulfate, chenodeoxycholic acid 7-alpha-sulfate and unsulfated chenodeoxycholic acid were quantified in isolated perfused rat liver. Influx of the 7-alpha- and 3-alpha-sulfated derivatives was 57% and 20% that of chenodeoxycholic acid, respectively. These three compounds bound to albumin equally well, indicating that this was not a factor in their differential uptake. Although single-pass extraction of material taken up by the liver was identical. There was no difference in bile flow or biliary excretion of material taken up by the liver was identical. There was no difference in bile flow or biliary excretion rate, regardless of which bile acid sulfate was tested. These results indicate that the low plasma elimination of sulfated bile acids previously observed by others can be explained by low hepatic influx. The diminished transport into liver resulting from sulfation could lead to enhanced elimination of bile acids by the kidney.

Animals↗
PubMed1990

Acute effects of ursodeoxycholic and chenodeoxycholic acid on the small intestinal absorption of bile acids.

The effects of ursodeoxycholic acid and chenodeoxycholic acid on the small-intestinal absorption of endogenous bile acids were studied in patients with ileostomies who served as a model to investigate small-intestinal absorption in humans. In the control period, the eight patients excreted 327 +/- 91 (mean +/- standard error of the mean) mumol/8 h cholic acid and 214 +/- 38 mumol/8 h chenodeoxycholic acid by their ileal fluid. Following ursodeoxycholic acid administration (500 mg), ileal excretion of cholic acid increased to 517 +/- 96 mumol/8 h, and that of chenodeoxycholic acid increased to 337 +/- 42 mumol/8 h, indicating decreased absorption of these bile acids. Following chenodeoxycholic acid administration (500 mg), no significant increase of cholic acid excretion was observed, whereas chenodeoxycholic acid excretion increased as expected. It is concluded that following ursodeoxycholic acid administration the absorption of common bile acids from the small intestine decreases markedly. This effect of ursodeoxycholic acid on intestinal absorption of common bile acids probably is responsible for the decrease of their plasma concentrations, the reduction of their pool sizes, the increase of their fractional turnover rates, and most likely also contributes to the increased hepatic synthesis of cholic acid.

Adult↗
PubMed1990

Ursodeoxycholic acid in primary biliary cirrhosis: no evidence for toxicity in the stages I to III.

In an open, exploratory study, the safety of ursodeoxycholic acid (UDCA) in the treatment of primary biliary cirrhosis (PBC) was investigated. Seven patients in stages I to III and two patients in stage IV were treated for 1 year with 1 g/day of UDCA. Clinical symptoms, and alkaline phosphatase, gamma-glutamyltransferase, alanine aminotransferase (GOT) and aspartate aminotransferase (GTP) levels improved significantly within three months and remained at the lower levels for the period of observation. Results of the galactose elimination capacity (4.7 +/- S.D. 1.4 mg/min per kg) and the aminopyrine breath test (0.60 +/- 0.33% dose/kg per mmol CO2) remained unchanged for 1 year. In all patients total serum bile acids increased and quantitatively UDCA became the most important bile acid. In patients in stages I to III this increase, however, was modest, whereas in patients in stage IV, total serum bile acids reached levels of 140 and 157 mumol/l and UDCA, levels of 90 and 103 mumol/l, respectively. It is concluded that UDCA appears to be safe only in stages I to III and that prognostic stratification based on bile acid levels or on the histological stage of the disease should be an important aspect of controlled clinical trials.

Aged↗
PubMed1990

Detection of large intrahepatic cholangiectases in patients with primary sclerosing cholangitis by endoscopic retrograde cholangiography.

Cholangiographic features of primary sclerosing cholangitis are multiple strictures and alternating dilated and normal segments of both intra- and extrahepatic bile ducts. Formerly, intrahepatic cholangiectases have been shown only in explanted livers, but we now describe the presence of large intrahepatic cholangiectases in a 22-year-old male patient with primary sclerosing cholangitis, visualized using a balloon catheter at endoscopic retrograde cholangiography. Cholangiectases in this patient appear to have been caused by the disease and not as a result of prestenotic dilatations. To treat possible early complications of this condition, we recommend looking for these cholangiectases when diagnostic endoscopic retrograde cholangiography is performed in primary sclerosing cholangitis.

Adult↗
PubMed1990

[Oral litholytic therapy--a reliable therapeutic principle?].

Oral litholysis by bile acids be used for the treatment of non-calcified cholesterol gallstones but not for the treatment of pigment stones. A prerequisite is that the patient has no complicated gallstone disease, has relatively little symptoms and has a functioning gallbladder. Gallstones with a diameter of more than 1.0 cm, before oral bile acid treatment, should undergo fragmentation by lithotripsy.

Administration, Oral↗
PubMed1990

[Oral litholysis].

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Chenodeoxycholic Acid↗
PubMed1989

Taurine and glycine conjugation and sulfation of lithocholate in primary hepatocyte cultures.

Rat primary liver cells were used to study taurine and glycine conjugation and sulfation of lithocholate. After addition of [14C]lithocholate to the tissue culture medium, synthesis and excretion of amidated and/or sulfated products were investigated for up to 24 h. After incubation for 1 h, more than 83% of the labeled bile salt was amidated but not sulfated and between 5 and 11% was sulfated, with more than 80% of the sulfated bile salts being also amidated. After 24 h, the proportion of sulfated lithocholate had increased to about 23% and more than 99% of the lithocholate sulfate was additionally conjugated with glycine or taurine. Both sulfates and non-sulfates were preferably amidated with taurine. We conclude that in primary rat hepatocytes, (1) lithocholate is rapidly and almost completely conjugated with glycine or taurine (amidated), whereas sulfation of lithocholate (and its amidates) proceeds slowly and even after 24 h represents only a small proportion of the total lithocholate metabolites, and (2) sulfated and unsulfated bile salts are both preferably amidated with taurine.

Amides↗
PubMed1989

Similarities in maximal biliary bilirubin output in the normal rat after administration of unconjugated bilirubin or bilirubin diglucuronide.

The rate-limiting step in the overall plasma-to-bile transport of a saturating load of bilirubin is still a matter of controversy. We reassessed the apparent maximal biliary bilirubin excretion following i.v. infusion of unconjugated bilirubin and--for the first time--of highly purified bilirubin diglucuronide in the rat. The bilirubin diglucuronide preparation could be kept in a stable form at -20 degrees C for at least 2 months after addition of 3 mM sodium ascorbate. The biliary bilirubin excretion rates in animals with and without bile depletion in order to induce different flow rates were comparable after infusion of unconjugated bilirubin and of bilirubin diglucuronide. No significant hydrolysis of bilirubin diglucuronide seemed to occur during the hepatic transport of the pigment. Injection of bilirubin diglucuronide into rats which were already being infused with saturating doses of unconjugated bilirubin did not result in increased biliary bilirubin excretion. In contrast, a reversible inhibition of bilirubin output and bile acid-dependent bile flow was observed. If unconjugated and diglucuronidated bilirubin follow the same intracellular routes, the present results would suggest that conjugation did not restrict maximal biliary excretion. However, if exogenously administered diglucuronide utilizes a separate pathway, as was recently proposed, the biliary secretion of this exogenous conjugate might be restricted, presumably due to a toxic effect of the high local concentration of diglucuronide. The pathways utilized by the unconjugated pigment, on the other hand, could be primarily determined by the conjugating capacity.

Animals↗