hymecromone and Liver-Diseases

Topics: Biliary Tract Diseases; Cholagogues and Choleretics; Chronic Disease; Clinical Trials as Topic; Humans; Hymecromone; Liver Diseases; Parasympatholytics

The enzyme beta-galactosidase present in the Kupffer cells of the liver has potential as a marker of liver dysfunction prior to transplantation. Spectrophotometric methods have insufficient sensitivity.. Fluorimetric methods have the required sensitivity and we have optimised such a method in a microtitre plate format to improve its utility. beta-galactosidase acts on the substrate 4-methylumbelliferyl-galactoside (MUG) to produce 4-methylumbelliferone (4-MU), detected fluorimetrically with excitation wavelength 355 nm and emission wavelength 460 nm.. Reaction conditions in a citrate-phosphate buffer were optimised to give maximal enzyme activity: pH was optimal at 4.4 (range investigated 3.6-5.0) and substrate concentration at 3.33 mmol/l. A small specimen volume (10 microl) in 80 microl of substrate solution produced adequate fluorescent yield after an incubation period of 30 to 60 min at 37 degrees C. Reaction was terminated by addition of 200 microl of glycine-NaOH, pH 12.8. The assay is linear to 3,000 U/ml. The intra-assay coefficient of variation (CV%) at 50, 502, and 2,012 U/ml was 4.7, 3.1, and 3.4, respectively (n=10). Inter-assay CV% at 51, 496, and 1,986 U/ml was 7.0, 4.0, and 3.9, respectively (n=10).. The assay has greater practical utility and demonstrated significant differences in the perfusate beta-galactosidase between cold-stored and warm-perfused livers in a porcine model of transplantation.

Topics: Animals; beta-Galactosidase; Buffers; Calibration; Citrates; Fluorometry; Humans; Hydrogen-Ion Concentration; Hymecromone; Kinetics; Liver; Liver Diseases; Liver Transplantation; Models, Biological; Nitrophenylgalactosides; Phosphates; Reproducibility of Results; Sensitivity and Specificity; Swine

Glucuronidation of 7-hydroxy-4-methylcoumarin (7-H-4-MC) by microsomal UDP-glucuronosyltransferases from 12 human liver biopsy samples was studied. Glucuronidation rates were highest for livers with mild cholestasis while those for livers with mild fatty changes were similar to normal livers. The lowest rates were exhibited by livers showing primary or metastatic carcinoma on histological examination. Thus, glucuronidation of not only bile acids but also of other substrates such as 7-H-4-MC may be elevated in cholestasis. These results are also consistent with other studies stating that glucuronidation might be spared in certain mild hepatic diseases.

Topics: Adult; Aged; Female; Glucuronosyltransferase; Humans; Hymecromone; In Vitro Techniques; Liver Diseases; Male; Microsomes, Liver; Middle Aged

Topics: Bile; Biotransformation; Chronic Disease; Humans; Hymecromone; Liver; Liver Diseases; Umbelliferones

Topics: Acute Disease; Bile Acids and Salts; Cholagogues and Choleretics; Chronic Disease; Food; Humans; Hymecromone; Liver Diseases; Middle Aged; Umbelliferones