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Gastroenterology Oct 1992To assess the frequency of antibodies to liver/kidney microsome type 1 (anti-LKM1) in patients with chronic active hepatitis, 131 such patients were tested by an...
To assess the frequency of antibodies to liver/kidney microsome type 1 (anti-LKM1) in patients with chronic active hepatitis, 131 such patients were tested by an indirect immunofluorescence assay. Of 62 patients with type 1 autoimmune hepatitis, none were seropositive. In contrast, 3 of 11 patients with autoimmune hepatitis and antimitochondrial antibodies (27%) were seropositive for anti-LKM1. Each had responded to corticosteroid therapy, and retesting of sera confirmed that each had been misclassified as antimitochondrial antibody positive. None of the patients with chronic active hepatitis B (14 patients) or C (24 patients) had anti-LKM1. Similarly, none of the 20 patients with cryptogenic disease had these antibodies. It is concluded that anti-LKM1 is specific for type 2 autoimmune hepatitis and is infrequent in adult patients seen at a referral center in the United States for chronic active hepatitis. Anti-LKM1 reactivity may be misinterpreted as antimitochondrial antibody reactivity by indirect immunofluorescence. Chronic hepatitis B and C virus infections are not important stimuli for the production of anti-LKM1, and testing for anti-LKM 1 is unlikely to clarify the nature of cryptogenic disease.
Topics: Adult; Autoantibodies; Autoimmune Diseases; Female; Hepatitis, Chronic; Humans; Kidney; Male; Microsomes; Microsomes, Liver; Middle Aged
PubMed: 1397887
DOI: 10.1016/0016-5085(92)91518-9 -
Clinical and Experimental Immunology Mar 1989Sera from 23 children with autoimmune chronic active hepatitis and positive for anti-liver-kidney-microsome antibody (LKMA), as defined by immunofluorescence, were...
Sera from 23 children with autoimmune chronic active hepatitis and positive for anti-liver-kidney-microsome antibody (LKMA), as defined by immunofluorescence, were analysed by Western blot (WB) and two-dimensional gel electrophoresis using rat liver microsomes as antigen, and by WB and dot-blot analysis with rat liver microsomal subfractions. Western blot analysis showed three patterns of reactivity: 13 sera recognized a 50 kD polypeptide, six sera a 66 kD polypeptide and four sera both of them. Two-dimensional gel electrophoresis, WB, and dot-blot analysis showed the 66 kD antigen to have a pI of 5.4 and to be located in the smooth domain of the endoplasmic reticulum. Western blot analysis using monospecific antisera against human IgG subclasses showed the LKMA directed against the 66 kD antigen to be mainly of the IgG1 subclass. These results indicate that LKMA associated with a subgroup of autoimmune hepatitis of children react with at least two different microsomal antigens in rat liver: (1) the 50 kD polypeptide, recently shown to be a cytochrome P-450 of the IID subfamily, and (2) a new antigen of 66 kD, the location of which suggests it may also be part of the mono-oxygenase complex.
Topics: Autoantibodies; Autoantigens; Autoimmune Diseases; Blotting, Western; Child; Female; Hepatitis, Chronic; Humans; Immunoglobulin G; Kidney; Male; Microsomes; Microsomes, Liver
PubMed: 2702779
DOI: No ID Found -
Chemico-biological Interactions Nov 1975The binding of tritium-labeled 7,12-dimethylbenz[a]anthracene (DMBA), benzo[a]pyrene (BP) and 3-methylcholanthrene (MCA) to DNA or polynucleotides in vitro was...
The binding of tritium-labeled 7,12-dimethylbenz[a]anthracene (DMBA), benzo[a]pyrene (BP) and 3-methylcholanthrene (MCA) to DNA or polynucleotides in vitro was re-examined both in the presence and in the absence of rat liver or human placental microsomes. A high level of non-enzymatic binding was evident when thymus DNA was used as acceptor. This non-enzymatic binding made it difficult to determine the effect of microsomes, except in the case of BP when induced rat microsomes were used. Better results were obtained using polynucleotides: a definite microsome-dependent binding occurred between all the polynucleotides and all the hydrocarbons tested. No clear evidence of binding catalysed by microsomes from human placenta was found except in polynucleotide-BP interactions: further studies are required to completely evaluate the ability of such nucleic acid-microsomal system for testing in vitro possible oncogenic substances in animals and humans.
Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Benz(a)Anthracenes; Benzopyrenes; Binding Sites; DNA; Female; Humans; Kinetics; Male; Methylcholanthrene; Microsomes; Microsomes, Liver; Placenta; Poly A; Poly G; Poly U; Polynucleotides; Pregnancy; Rats; Receptors, Drug
PubMed: 811363
DOI: 10.1016/0009-2797(75)90004-6 -
Mutation Research Dec 2005Genotoxicity is one of the important endpoints for risk assessment of environmental chemicals. Many short-term assays to evaluate genotoxicity have been developed and... (Comparative Study)
Comparative Study
Genotoxicity is one of the important endpoints for risk assessment of environmental chemicals. Many short-term assays to evaluate genotoxicity have been developed and some of them are being used routinely. Although these assays can generally be completed within a short period, their throughput is not sufficient to assess the huge number of chemicals, which exist in our living environment without information on their safety. We have evaluated three commercially available in silico systems, i.e., DEREK, MultiCASE, and ADMEWorks, to assess chemical genotoxicity. We applied these systems to the 703 chemicals that had been evaluated by the Salmonella/microsome assay from CGX database published by Kirkland et al. We also applied these systems to the 206 existing chemicals in Japan that were recently evaluated using the Salmonella/microsome assay under GLP compliance (ECJ database). Sensitivity (the proportion of the positive in Salmonella/microsome assay correctly identified by the in silico system), specificity (the proportion of the negative in Salmonella/microsome assay correctly identified) and concordance (the proportion of correct identifications of the positive and the negative in Salmonella/microsome assay) were increased when we combined the three in silico systems to make a final decision in mutagenicity, and accordingly we concluded that in silico evaluation could be optimized by combining the evaluations from different systems. We also investigated whether there was any correlation between the Salmonella/microsome assay result and the molecular weight of the chemicals: high molecular weight (>3000) chemicals tended to give negative results. We propose a decision tree to assess chemical genotoxicity using a combination of the three in silico systems after pre-selection according to their molecular weight.
Topics: Biological Assay; Computer Simulation; Databases, Factual; Microsomes; Mutagenicity Tests; Mutagens; Salmonella; Structure-Activity Relationship
PubMed: 16257575
DOI: 10.1016/j.mrgentox.2005.09.009 -
Clinical and Experimental Immunology Mar 1984The sera of 131 patients with anti-liver-kidney microsome antibodies (anti-LKM) detected between 1973 and 1979 in two different laboratories were re-examined. (1)... (Comparative Study)
Comparative Study
The sera of 131 patients with anti-liver-kidney microsome antibodies (anti-LKM) detected between 1973 and 1979 in two different laboratories were re-examined. (1) Eighty-six anti-LKM corresponded to the description given by Rizzetto, Swana & Doniach (1973), with a pattern of fluorescence predominating on the 3rd portion of the proximal tubules (P3). This group comprised 45 cases of idiopathic chronic hepatitis or idiopathic cirrhosis and one case of halothane-induced hepatitis. (2) Forty-five anti-LKM gave a different pattern on male mouse liver and male rat kidney: (a) fluorescence was greater on centrolobular than on periportal hepatocytes; (b) the first and second portions of proximal tubules (P1 and P2) predominated over P3; (c) P1 fluorescence was equally intense as P2 and (d) P3 cells were heterogeneous with one cell out of 20 more positive than the rest. Absorption tests confirmed that the corresponding antigen was also present in the liver microsomal fraction. A retrospective clinical study discovered tienilic acid-induced hepatitis in all cases. We suggest naming this new antibody 'anti-LKM2'.
Topics: Adolescent; Adult; Aged; Animals; Autoantibodies; Chemical and Drug Induced Liver Injury; Child; Child, Preschool; Female; Fluorescent Antibody Technique; Glycolates; Humans; Kidney; Liver Diseases; Male; Mice; Microsomes; Microsomes, Liver; Middle Aged; Rats; Retrospective Studies; Ticrynafen
PubMed: 6368059
DOI: No ID Found -
Zhongguo Yao Li Xue Bao = Acta... Sep 1989The effects of nortriptyline in vitro on the activities of optical isomer and racemate bufuralol 1'-hydroxylase in man and Wistar rat liver microsomal fractions were...
The effects of nortriptyline in vitro on the activities of optical isomer and racemate bufuralol 1'-hydroxylase in man and Wistar rat liver microsomal fractions were studied. There was a dose-dependent inhibitory effect of nortriptyline on bufuralol 1'-hydroxylase in both species. While the concentration of nortriptyline greater than or equal to 0.32 mumol/L and greater than or equal to 1.6 mumol/L, the activities of (+), (-) and (+/-) bufuralol 1'-hydroxylase were significantly reduced in man and rat, respectively. The values of inhibitor concentration causing 50% reduction (IC50) to (+), (-) and (+/-) bufuralol 1'-hydroxylase were 10, 19 and 14 mumol/L for human and 4, 10, 6 mumol/L for rat, respectively. It was shown by improved Dixon's plot that the inhibitory type was competitive, and the inhibitory constant (Ki) values to (+), (-) and (+/-) bufuralol 1'-hydroxylase were 5, 3, 4 mumol/L for human and 55, 29, 43 mumol/L for rat, respectively. These results indicate that nortriptyline is a very potent competitive inhibitor to bufuralol 1'-hydroxylase in man and Wistar rat.
Topics: Animals; Cytochrome P-450 Enzyme System; Humans; In Vitro Techniques; Male; Microsomes, Liver; Mixed Function Oxygenases; Nortriptyline; Rats; Rats, Inbred Strains; Stereoisomerism
PubMed: 2618737
DOI: No ID Found -
Journal of Pharmaceutical Sciences Nov 2022The purpose of this study was to investigate the optimal pH for acyl-glucuronidation formation with carboxylic acid-containing compounds in human and rat liver...
The purpose of this study was to investigate the optimal pH for acyl-glucuronidation formation with carboxylic acid-containing compounds in human and rat liver microsomes to improve the predictability of their hepatic clearance. The optimal pH for acyl-glucuronidation of all 17 compounds was around pH 6.0 in human and rat liver microsomes. Correlation analysis was done with the predicted in vitro intrinsic clearance (CL) and in vivo intrinsic clearance (CL) calculated from available reported data of total clearance (CL) of 11 compounds in humans. For 8 of the 11 compounds, under the pH 6.0 condition, the CL were within 1/3 to 3-fold error of the observed CL whereas, the error was within 1/3 to 3-fold of the observed CL for only 3 of the 11 under the pH 7.4 condition. The intracellular pH in human and rat hepatocytes decreased in the presence of a carboxylic acid-containing compound. These findings suggest that acyl-glucuronidation in liver microsomes at pH 6.0 is closer to physiological conditions in the presence of carboxylic acid compounds, and thus, use of this pH condition is important for physiological interpretation and predictability of intrinsic clearance.
Topics: Animals; Carboxylic Acids; Glucuronosyltransferase; Hepatocytes; Humans; Hydrogen-Ion Concentration; Liver; Microsomes; Microsomes, Liver; Rats
PubMed: 35995204
DOI: 10.1016/j.xphs.2022.08.015 -
The Biochemical Journal Jan 19681. In further studies on the biosynthesis of components of fraction I, an acidic glycoprotein-containing fraction from guinea-pig serum, an investigation was made of the...
1. In further studies on the biosynthesis of components of fraction I, an acidic glycoprotein-containing fraction from guinea-pig serum, an investigation was made of the substances bound to liver microsomes that had earlier been implicated to participate in the synthesis of components of fraction I present in serum. These substances were normally liberated by ultrasonic vibrations. Antisera to subfractions of fraction I were used for characterization. 2. At pH8.6, most of the microsome-bound substances showed electrophoretic mobilities lower than components of fraction I but similar to components of sialic acid-free fraction I. 3. The sialic acid/protein ratios of immune precipitates formed by microsome extracts were similar to those of precipitates formed by sialic acid-free fraction I. 4. On chromatography on Sephadex G-150, most of the microsomal substances were eluted at an essentially similar volume to the main components of fraction I. 5. It was concluded that most of the microsome-bound substances lack sialic acid residues, and, as appreciable degradation of completed molecules is unlikely, these substances appear to be precursors of serum glycoprotein molecules with incomplete prosthetic groups. 6. Evidence was obtained on the submicrosomal localization of incomplete and complete serum glycoprotein molecules.
Topics: Animals; Antigens; Carbon Isotopes; Chromatography, Gel; Electrophoresis; Glucosamine; Glycoproteins; Guinea Pigs; Humans; Hydrogen-Ion Concentration; Immune Sera; Immunoelectrophoresis; Leucine; Liver; Microsomes; Neuraminic Acids; Ultrasonics
PubMed: 5721460
DOI: 10.1042/bj1060023 -
Biochemical Pharmacology Jul 1965
Topics: Animals; Body Weight; In Vitro Techniques; Leucine; Liver; Microsomes; Organ Size; Phenobarbital; Protein Biosynthesis; RNA, Messenger; Rats
PubMed: 5854742
DOI: 10.1016/0006-2952(65)90047-x -
Xenobiotica; the Fate of Foreign... Sep 2010We compare three different approaches to scale clearance (CL) from human hepatocyte and microsome CL(int) (intrinsic CL) for 52 drug compounds. By using the well-stirred...
We compare three different approaches to scale clearance (CL) from human hepatocyte and microsome CL(int) (intrinsic CL) for 52 drug compounds. By using the well-stirred model with protein binding included only 11% and 30% of the compounds were predicted within 2-fold and the average absolute fold errors (AAFE) for the predictions were 5.9 and 4.1 for hepatocytes and microsomes, respectively. When predictions were performed without protein binding, 59% of the compounds were predicted within 2-fold using either hepatocytes or microsomes and the AAFE was 2.2 and 2.3, respectively. For hepatocytes and microsomes there were significant correlations (P = 8.7 x 10(-13), R(2) = 0.72; P = 2.8 x 10(-9), R(2) = 0.61) between predicted CL(int in vivo) (obtained from in vitro CL(int)) and measured CL(int in vivo) (obtained using the well-stirred model). When CL was calculated from the regression, 76% and 70% of the compounds were predicted within 2-fold and the AAFE was 1.6 and 1.8 for hepatocytes and microsomes, respectively. We demonstrate that microsomes and hepatocytes are in many cases comparable when scaling of CL is performed from regression. By using the hepatocyte regression, CL for 82% of the compounds in an independent test set (n = 11) were predicted within 2-fold (AAFE 1.4). We suggest that a regression line that adjusts for systematic under-predictions should be the first-hand choice for scaling of CL.
Topics: Female; Hepatocytes; Humans; Male; Metabolic Clearance Rate; Microsomes; Models, Biological; Pharmaceutical Preparations; Regression Analysis
PubMed: 20624033
DOI: 10.3109/00498254.2010.500407