Search results for "CYP"
showing 10 items of 480 documents
Development of cytochrome P450 2D6-specific LKM-autoantibodies following liver transplantation for Wilson's disease -- possible association with a st…
1999
Abstract Background/Aims: Antibodies to cytochrome P450 2D6, also knownas LKM1-autoantibodies, are characteristic for a subgroup of patients with autoimmune hepatitis, but can also occasionally be found in hepatitis C. We observed the occurrence of LKM1-autoantibodies 4 months after liver transplantation for Wilson's disease, in close association with a steroid-resistant rejection episode, in the absence of evidence for autoimmune hepatitis or hepatitis C. Methods: Sera from several time points prior to and following transplantation were tested for LKM-reactivity by immunofluorescence, ELISA and Western blotting. Antigen specificity was confirmed by Western blotting analysis on different cy…
Unusual high dose of tacrolimus in liver transplant patient, a case report.
2012
Case We describe the case of a liver transplant patient who had great difficulty in reaching the desired trough blood levels despite the use of high dose tacrolimus. The patient was homozygous for the CYP3A5*3 allele. However, the respective donor carried the wild-type CYP3A5*1/*1 genotype. Regarding ABCB1 SNPs at exon 21 and 26, the patient showed the 2677GT and 3435CC genotypes. For the corresponding donor we observed the 2677GG and 3435CC wild-type genotypes. One, two and three weeks after transplantation the patient received daily 0.219, 0.287 and 0.273 mg/kg of tacrolimus, respectively. However, the corresponding tacrolimus trough blood levels were of 4.6, 5.6 and 6.1 ng/mL. The tacrol…
Association of CYP2R1 rs10766197 with MS risk and disease progression
2017
Background MS is a neurodegenerative autoimmune disease resulting from a complex interaction of genetic and environmental factors. Among these, vitamin D and genetic variants associated with vitamin D-metabolism gain great attention. The aim of our study was to assess five SNPs in NADSYN1 and CYP2R1 genes in relation to serum 25-OH-vitamin D3 levels in MS patients and controls. Methods 25-OH-vitamin D3 levels and genotyping of CYP2R1- and NADSYN1-SNPs were investigated both in MS patients and in healthy controls. Results The analysis revealed lower 25-OH-vitamin D3 concentrations in MS patients than in controls and an association of rs10766197 CYP2R1 SNP with MS risk. After stratifying MS p…
Angiopoietin-Like Protein 8 Is a Novel Vitamin D Receptor Target Gene Involved in Nonalcoholic Fatty Liver Pathogenesis
2018
Hepatic vitamin D receptor (VDR) expression is increased in patients with nonalcoholic fatty liver (NAFL) and is required for liver steatosis in an NAFL mouse model. However, how hepatocyte VDR is involved in setting up steatosis remains unclear. The authors transduced human hepatocyte-derived cells with an adenoviral vector encoding human VDR and found that angiopoietin-like protein 8 (ANGPTL8) expression was increased upon VDR activation by vitamin D or lithocholic acid. The mRNA levels of hepatic VDR- and vitamin D-related genes [cytochrome P450 (CYP) 2R1, CYP27A1, and CYP3A4] were higher in NAFL patients compared with normal liver subjects. Noteworthy, hepatic ANGPTL8 mRNA and protein l…
Cytochrome P-450 mRNA expression in human liver and its relationship with enzyme activity.
2001
CYP activity and protein contents have been measured in human liver using different techniques. In contrast, CYP mRNA data are scarce and the relationships between CYP mRNA contents and activities have not been established. These studies deserve further attention because mRNA determinations by RT-PCR require a very small amount of material (e.g., liver needle biopsy) and could provide important data regarding CYP expression regulation. In this study we measured in 12 human liver samples the mRNA contents of 10 CYPs by quantitative RT-PCR and the metabolic activities using specific substrates. mRNA contents and activities showed high correlation coefficients for CYP1A1, CYP1A2, CYP3A4, CYP2D…
Serum levels of aripiprazole and dehydroaripiprazole, clinical response and side effects
2007
Aripiprazole, a novel antipsychotic drug, is metabolized by CYP3A4 and CYP2D6 forming mainly its active metabolite dehydroaripiprazole. In this study, aripiprazole and dehydroaripiprazole serum levels of psychiatric patients were measured and related to dose, comedication, and clinical effects including therapeutic and side effects. Patients were treated with mean doses of 20 +/- 8 mg/day of aripiprazole (median 15 mg, range 7.5-60 mg). Serum levels correlated significantly with the dose (r = 0.419; P0.01), with a mean value of aripiprazole of 214 +/- 140 ng/ml. Mean concentrations of the active metabolite dehydroaripiprazole amounted to 40% of the parent compound. Comedication with CYP3A4 …
Rapid and reliable genotyping procedure for detection of alleles with mutations, deletion, or/and duplication of the CYP2D6 gene
2009
Abstract Background Polymorphisms of cytochrome P450 2D6 (CYP2D6) have a significant effect on the pharmacokinetics of most tricyclic antidepressants. More than 150 alleles lead to four distinct phenotypes of drug metabolism. The phenotypes are described as ultrarapid, extensive, intermediate, and poor metabolizers. Therapeutic plasma levels of CYP2D6 substrates may be difficult to achieve. Here we describe a rapid and reliable procedure for CYP2D6*4, *3, *6, and *9 genotyping. Design and methods Serum concentrations of venlafaxine and its pharmacologically active metabolite, O-desmethylvenlafaxine, were measured in patients treated with the antidepressant venlafaxine, a substrate of CYP2D6…
The role of cytochrome P450 2D6 in the metabolism of moclobemide.
1996
The metabolic fate of moclobemide (Ro 11-1163), a new reversible and selective inhibitor of monoamine oxidase type A (MAO-A), has been assessed in a pilot study in 2 debrisoquine poor metabolizers (PM) and 4 extensive metabolizers (EM) after multiple oral dosings of moclobemide with and without co-medication of dextromethorphan. Absorption and disposition parameters were not different between PM and EM. Concurrent application of dextromethorphan, a selective substrate of CYP2D6, did not affect the pharmacokinetics of moclobemide. These results indicate that the cytochromal isoenzyme CYP2D6 does not play a major role in the metabolic degradation of moclobemide. Limited CYP2D6 activities beca…
CYP2D6 genotype and phenotyping by determination of dextromethorphan and metabolites in serum of healthy controls and of patients under psychotropic …
1998
Fourteen drug free healthy volunteers and 22 psychiatric patients under psychotropic medication were phenotyped for their individual CYP2D6 activity using dextromethorphan as a probe drug. A solution containing 20 mg dextromethorphan was administered and blood was taken 60 min later for determination of dextromethorphan and metabolites in serum. For comparison, urine was collected over 8 h after ingestion of 20 mg dextromethorphan in a separate test. The CYP2D6 phenotype was determined from the ratio of dextromethorphan to dextrorphan. For genotyping, mutant alleles of the CYP2D6 gene were identified using allele-specific polymerase chain reactions. Genotyping revealed five poor metabolizer…
Cytochrome P450 2E1 variable number tandem repeat polymorphisms and health risks: A genotype-phenotype study in cancers associated with drinking and/…
2012
Cytochrome P450 2E1 (CYP2E1) is one of the main enzymes involved in the oxidation of ethanol and in the transformation of a number of potentially dangerous compounds. It has various polymorphic sites, one of which is a variable number tandem repeat (VNTR) polymorphism previously described in the 5'-flanking region. The aim of this study was to investigate the genotype-phenotype association between CYP2E1 VNTR polymorphisms and risky health habits in healthy subjects and to analyze the associations between these polymorphisms with drinking- and/or smoking-related cancers. We analyzed 166 healthy subjects by genotyping for the CYP2E1 VNTR polymorphism associated with drinking and/or smoking h…