P M Mrozikiewicz

A1/A2 polymorphism of glycoprotein IIIa and association with excess procedural risk for coronary catheter interventions: a case-controlled study

BACKGROUND A five-fold increase in risk of stent thrombosis in carriers of A1/A2 (Leu33Pro) polymorphism of glycoprotein Illa has been described. Whether this increased procedural risk applies to other coronary interventions is unknown. We investigated the role of A1/A2 polymorphism as a putative risk factor. METHODS We genotyped 1000 consecutive patients with angiographically confirmed coronary-artery disease and 1000 controls matched for age and sex. 653 of the 1000 patients received interventions (271 coronary angioplasty, 102 directional coronary atherectomy, and 280 stenting) and were assessed for a 30-day composite endpoint of need for target-vessel revascularisation, myocardial infarction, and death. FINDINGS The composite endpoint occurred in 41 (6.3%) patients. There was no evidence that the A2 allele was associated with excess procedural risk (relative risk 1.36 [95% CI 0.70-2.70], p=0.37). Nor, in subgroup analyses, did A2 predict events that complicated coronary angioplasty (1.17 [0.40-2.70]), directional coronary atherectomy (1.50 [0.30-8.70]), or stenting (1.45 [0.60-3.50]). Neither heterozygotes (A1/A2) nor homozygotes (A2/A2) were over-represented in any subgroup, including those with acute coronary syndromes, early disease manifestation (age <40 years), and histories of myocardial infarction. INTERPRETATION A1/A2 polymorphism is not a major risk factor for 30-day adverse events that complicate coronary angioplasty, directional coronary atherectomy, or stenting. Furthermore, A1/A2 polymorphism has no apparent impact on more chronic processes such as atherogenesis of the coronary arteries.

Quantitative determination of MDR1 mRNA expression in peripheral blood lymphocytes: a possible role of genetic polymorphisms in the MDR1 gene.

Background P‐glycoprotein is a transmembrane efflux pump that extrudes a wide variety of drugs, thereby reducing their intracellular access. In humans, P‐glycoprotein is encoded by the MDR1 gene. Recently, several single nucleotide polymorphisms in the MDR1 gene were identified. Moreover, it was postulated that, in addition to the full‐length P‐glycoprotein, a ‘mini’ P‐glycoprotein was also present in lymphocytes.

Mutations in the human paraoxonase 1 gene : frequencies, allelic linkages, and association with coronary artery disease

Oxidative damage is a major cause of atherosclerosis. Since human paraoxonase has been postulated as a factor which plays a role in protection from low density lipoprotein oxidation, recent studies have dealt with the impact of hereditary PON1 gene polymorphisms as risk factors for coronary artery disease (CAD). The results from these studies are conflicting. In a case-control study, 1000 Caucasian patients with angiographically confirmed CAD were recruited and matched by age and gender to 1000 control individuals. PON1 mutations in codons 55 and 192 were evaluated by polymerase chain reaction-restriction fragment length polymorphism and allocated to defined haplotypes *1 (55L/192Q), *2 (55L/192R), and *3 (55M/192Q). Frequency of PON1 genotypes without any mutation (PON1*1/*1, wild-type) in CAD cases was 16.9% versus 17.1% in control individuals. PON1*2/*2 showed a frequency of 6.6% versus 7.3% (P = 0.68 compared to wild-type), and PON1*3/3 occurred in 11.8% in CAD cases versus 10.3% among control individuals (P = 0.40). There was also no difference in the distribution of carriers heterozygous for *2 or *3 among cases and control individuals. A haplotype containing both mutations 55M and 192R was not observed. None of the investigated genotypes demonstrated association with early manifestation, severity of disease, acute coronary syndromes, or myocardial infarction. Logistic regression analysis with adjustment for age, gender, diabetes, hypertension, hypercholesterolemia and smoking revealed no evidence of increased coronary risk associated with PON1 genotypes. These results suggest that PON1 polymorphisms are not major genetic determinants of CAD.

High frequency of CYP1A1 mutations in a Turkish population

Abstract The frequency distribution of four cytochrome P4501A1 (CYP1A1) gene mutations was investigated in 271 Turks from southeast Anatolia by polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) assay. Allelic linkage of those mutations was proven by peptide nucleic acid-mediated PCR clamping. Mutation m1 (T6235C) forming an MspI restriction site in the 3′-flanking region occurred with 18.1% frequency (95% confidence interval 14.9–21.6%), m2 (A4889G) leading to an Ile/Val exchange in exon 7 had a frequency of 8.9% (6.6–11.6%), and m4 (C4887A; Thr/Asn-exchange also in exon 7) occurred with 5.7% (3.9–8.0%). T5639C (m3) in the 3′-flanking region was not detected. m2 was exclusively found linked with m1 forming allele CYP1A1*2B. The frequency of this allele supposedly at-risk for lung cancer was significantly higher than in Middle European populations, but lower than in the Far East.

Determination and allelic allocation of seven nucleotide transitions within the arylamine N-acetyltransferase gene in the Polish population

The frequency of various genotypes of arylamine N‐acetyltransferase (NAT2) was investigated in 248 Polish unrelated children. Allele‐specific polymerase chain reaction (PCR) was applied for mutation at 341 nucleotide (nt) of NAT2 coding sequence and PCR/restriction fragment length polymorphism for the other mutations. Genotypes coded for slow acetylation in 62.9% (56.6% to 68.9%). The frequency of specific NAT2 alleles was *4 (wild‐type), 22.0%; *5A (341C, 481T), 5.2%; *5B (341C, 481T, 803G), 33.1%; *5C (341C, 803G), 6.0%; *6A (282T, 590A), 30.0%; *7B (282T, 857A), 3.4%; and *12A (803G), 0.2%. No mutations were found at 191, 434, and 845 nt. By a molecular‐genetic procedure, genotypes *4/*6A were confirmed not to mask *6B/*13 (590A/282T). *6B and *13 were absent in a composite sample representative of 826 alleles (95% confidence limits, 0% to 0.45%). Five cases of genotype‐phenotype discrepancy were sequenced and their mutation allocation confirmed; 21 further genotypes were confirmed by sequencing. This first evaluation of NAT2 genes among a Slavic population should provide a basis for clinical and epidemiologic investigations of NAT2 in the Polish population.

Quantitative determination of the human MRP1 and MRP2 mRNA expression in FACS-sorted peripheral blood CD4+, CD8+, CD19+, and CD56+cells

Objectives: ATP‐binding cassette (ABC) transporters extrude a wide variety of endogenous and exogenous compounds. In cancer cells, they are known to confer multidrug resistance. The aim of the present study was to determine the expression of the multidrug resistance‐associated protein 1 (MRP1) and 2 (MRP2), which are members of the subfamily C of the ABC transporters family, in human hematopoietic cells.

Arylamine N-acetyltransferase (NAT2) genotypes in a Turkish population.

A group of 303 unrelated Turkish subjects from south-east Anatolia was genotyped for seven NAT2 mutations by polymerase chain reaction-restriction fragment length polymorphism. Genotypes associated with slow acetylation were identified in 57.4% (95%-confidence limits, 51.6%-63.1%). Allele frequencies were NAT2*4 (wild type, 23.1%), *5A (1.3%), *5B (35.6%), *5C (4.8%), *6A (30.5%), *7B (4.5%), and *12A (0.2%). A mutation G191A was not detected. Ambiguous mutation linkages were checked by molecular genetic linkage analysis and DNA sequencing. NAT2-alleles in Turks are similarly distributed as in Middle European ethnicities.

CYP1A1 mutations 4887A, 4889G, 5639C and 6235C in the Polish population and their allelic linkage, determined by peptide nucleic acid-mediated PCR clamping.

Mutations in the CYP1A1 gene were investigated in 324 Polish children and adolescents using PCR/RFLP. Mutation T6235C (m1) occurred in 6.6% of alleles (95& confidence limits 4.8%-8.8%); A4889G (m2), 2.2% (1.2%-3.6%); and C4887A (m4), 2.0% (1.1%-3.4%). T5639C (m3) was not detected. Wild-type allele CYP1A1*1 was found in 91.4% (88.9%-93.4%). In all cases of theoretically possible mutation linkages, the novel method of allele specific polymerase chain reaction-clamping mediated by peptide nucleic acids was applied to define allelic allocation. All 14 individuals with an m2 mutation also had m1 on the same allele (CYP1A1*2B). Allele CYP1A1*2A, carrying only m1, appeared in 4.5% (3.0%-6.4%). In the single case of m1/m4, these mutations were placed on distinct alleles. CYP1A1 mutations in the Polish sample tended to be less frequent than in other Caucasian groups.

Polymorphic arylamine N‐acetyltransferase (NAT2) genes in children with insulin‐dependent diabetes mellitus

Polymorphic liver arylamine N‐acetyltransferase (NAT2; EC 2.3.1.5) has been suggested as a susceptibility factor for both insulin‐dependent diabetes mellitus (IDDM) and non‐insulin‐dependent diabetes mellitus. Previous studies reported an overrepresentation of phenotypically fast acetylators among patients with diabetes. With use of an allele‐specific nested polymerase chain reaction, the NAT2 genotypes were determined in 165 clinically well‐controlled patients with IDDM and 107 reference children aged from 3 to 18 years. Wild‐type and mutated alleles (mutation 1 diagnosed by presence of cytosin at position 341 instead of thymin; M2 by adenin at 590 instead of guanin, M3 by adenin at 857 instead of guanin) were distributed equally in both groups. Genotypes coding fast acetylation (homozygous wild‐type and heterozygous wild‐type with one of the mutations) were detected in 40.6% and 36.6% of children with IDDM and reference children, respectively (odds ratio, 1.19; 95% confidence limits, 0.70 to 2.04). In 66 children with IDDM and 54 reference children the NAT2 genotype was checked by conventional sulfamethazine (sulfadimidine) phenotyping. There were only five discrepant cases, indicating that NAT2 genotyping enables correct prediction of NAT2 phenotype in about 95% of tested individuals. The fast acetylator genotype could not be established as a host factor for IDDM susceptibility in children.

Cytochrome P450 3A4 messenger ribonucleic acid induction by rifampin in human peripheral blood mononuclear cells: Correlation with alprazolam pharmacokinetics

There is significant interest in the assessment of the individual cytochrome P450 (CYP) 3A4 activity. We analyzed whether CYP3A4 messenger ribonucleic acid (mRNA) concentrations in leukocytes reflect CYP3A activity in the liver measured by alprazolam as an in vivo probe drug. We also wanted to identify whether genetically determined high CYP3A5 expression is associated with increased alprazolam clearance.