Hyung-Kee Kim

Nicotine metabolism and CYP2A6 allele frequencies in Koreans

CYP2A6 is a major catalyst of nicotine metabolism to cotinine. Previously, we demonstrated that the interindividual difference in nicotine metabolism is related to a genetic polymorphism of the CYP2A6 gene in Japanese. To clarify the ethnic differences in nicotine metabolism and frequencies of CYP2A6 alleles, we studied nicotine metabolism and the CYP2A6 genotype in 209 Koreans. The cotinine/nicotine ratio of the plasma concentration 2 h after chewing one piece of nicotine gum was calculated as an index of nicotine metabolism. The genotypes of CYP2A6 gene (CYP2A6*1A, CYP2A6*1B, CYP2A6*2, CYP2A6*3, CYP2A6*4 and CYP2A6*5) were determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism or allele specific (AS)-PCR. There were ethnic differences in the allele frequencies of CYP2A6*1A, CYP2A6*1B, CYP2A6*4 and CYP2A6*5 between Koreans (45.7%, 42.8%, 11.0% and 0.5%, respectively) and Japanese (42.4%, 37.5%, 20.1% and 0%, respectively, our previous data). Similar to the Japanese, no CYP2A6*2 and CYP2A6*3 alleles were found in Koreans. The homozygotes of the CYP2A6*4 allele (four subjects) were completely deficient in cotinine formation, being consistent with the data among Japanese. The heterozygotes of CYP2A6*4 tended to possess a lower metabolic ratio (CYP2A6*1A/CYP2A6*4, 4.79 +/- 3.17; CYP2A6*1B/CYP2A6*4, 7.43 +/- 4.97) than that in subjects without the allele (CYP2A6*1A/CYP2A6*1A, 7.42 +/- 6.56; CYP2A6*1A/CYP2A6*1B, 9.85 +/- 16.12; CYP2A6*1B/CYP2A6*1B, 11.33 +/- 9.33). The subjects who possess the CYP2A6*1B allele appeared to show higher capabilities of cotinine formation. It was confirmed that the interindividual difference in nicotine metabolism was closely related to the genetic polymorphism of CYP2A6. The probit plot of the metabolic ratios in Koreans (8.73 +/- 11.88) was shifted to a higher ratio than that in the Japanese (3.78 +/- 3.09). In each genotype group, the Korean subjects revealed significantly higher metabolic ratios than the Japanese subjects. The ethnic difference in cotinine formation might be due to environmental and/or diet factors as well as genetic factors.

Metabolic disposition of lansoprazole in relation to the S‐mephenytoin 4′‐hydroxylation phenotype status

To assess the possible involvement of CYP2C19 in the metabolism of lansoprazole in vivo.

Pharmacokinetics of Glutathione and Its Metabolites in Normal Subjects

To determine the loading and maintenance dosage of glutathione (GSH) for patients suffering from reactive oxygen species (ROS) injury such as acute paraquat intoxication, a kinetic study of reduced GSH was performed in synchrony with that of cysteine (Cys), cystine (Cys2), and methionine (Met). Human subjects porticipitation was voluntary. The effective dose of Cys, Cys2, and Met against ROS in fibroblast cells generated by paraquat was assessed using laser scanning confocal microscopy. Both Cys and Met suppressed ROS in a dose-dependent manner at concentrations of 1-1,000 µM; the concentration required to suppress ROS by 50% was 10 µM for Cys and 50 µM for Met. Using metabolite kinetics with the assumption that Cys and Met are the metabolites of GSH, expected concentrations of Cys and Met of above 20 and 50 µM were estimated when GSH was administered at 50 mg/kg body weights every 205.4 min for Cys and 427.4 min for Met.

Lasp1 is down-regulated in NMDA receptor antagonist-treated mice and implicated in human schizophrenia susceptibility

Mice treated with MK-801, a non-competitive antagonist of the N-methyl-d-aspartic (NMDA) acid receptor, are important animal models for schizophrenia studies. In the present study, we compared protein expression levels in the hippocampus of mice treated with MK-801 (0.6 mg/kg) or saline once daily for 7 days. Changes in the proteome were detected by two-dimensional electrophoresis, and the six proteins exhibiting differential expression were identified by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. Down-regulation of one of these proteins, Lasp1 (LIM and SH3 protein 1), in MK-801-treated mice was confirmed by western blotting and immunohistochemical analyses. Lasp1 is a multidomain protein that may recruit signaling molecules to the actin-based cytoskeleton and is known to concentrate in synaptic sites of hippocampal neurons. We next investigated whether polymorphisms in the human LASP1 gene were associated with schizophrenia in the Korean population. A single-nucleotide polymorphism in the LASP1 gene promoter region was associated with schizophrenia susceptibility. Our results suggest that LASP1 might be associated with NMDA receptor antagonism and schizophrenia susceptibility and, thus, might be involved in the pathophysiology of schizophrenia.

Association of ADAMTS12 polymorphisms with rheumatoid arthritis

a disintegrin and metalloproteinase (ADAM) with thrombospondin type 1 motif 12 (ADAMTS12) is a degradative enzyme that interacts with the degradable fragments of cartilage oligomeric matrix protein, which is a prominent non-collagenous matrix component in articular cartilage. ADAMTS12 has been observed in the cartilage, synovial fluid and serum of arthritic patients, and may play an important role in the pathogenesis of arthritis. In the present study, we investigated whether genetic polymorphisms of ADAMTS12 are associated with rheumatoid arthritis (RA). To observe the association between ADAMTS12 and RA, we genotyped three single nucleotide polymorphisms (SNPs) (rs1364044, intron C/T; rs10461703, intron C/T; rs25754, missense Thr1495Ile) of ADAMTS12 using a direct sequencing method in 303 RA patients and 495 control subjects. Multiple logistic regression models were performed to analyze the genetic data. SNPStats and SNPAnalyzer Pro programs were used to estimate the odds ratios, 95% confidence intervals and p-values. Bonferronis correction (pc) was conducted to obtain a defined result. Of the three SNPs, the genotype frequency of rs10461703 was associated with the development of RA (pc=0.0024 in the co-dominant model; pc=0.0009 in the dominant model; pc=0.0006 in the log-additive model). The allele frequency of rs10461703 also showed a significant difference between RA and controls (pc<0.0001). The C allele frequency of rs10461703 was lower in the RA group (36.6%) compared to the control group (45.7%), whereas the T allele frequency of rs10461703 in the RA group (63.4%) was higher compared to that in the control group (54.3%). The other two SNPs (rs1364044 and rs25754) were not associated with the development of RA. However, we did not find any association between the three tested SNPs and RA patients according to clinical features, including erythrocyte sedimentation rate, C-reactive protein level, rheumatoid factor (+ and -) and bone erosion (+ and -). Our results suggest that ADAMTS12 may be a susceptibility gene for RA development.

Association between TAP1 gene polymorphisms and alopecia areata in a Korean population.

The transporter 1 ATP-binding cassette sub-family B (MDR/TAP) gene (TAP1) is located in the major histocompatibility complex class II region, and forms a heterodimer that plays a key role in endogenous antigen presentation pathways. Investigation of polymorphisms identified in these loci has revealed an association with several autoimmune disorders. Alopecia areata (AA) is a common autoimmune disease resulting from T cell-induced damage to hair follicles. The present study documents for the first time a comparison between the allelic and genotypic frequencies of TAP1 single nucleotide polymorphisms (SNPs) in patients with AA and those of a control group, using a direct sequencing method. Our results suggest an association between a promoter SNP (rs2071480) and susceptibility to this disease.

Influence of S-Mephenytoin Phenotype on the Lansoprazole Metabolism

Clinical Pharmacology & Therapeutics (1996) 59, 137–137; doi: 10.1038/sj.clpt.1996.49

Corrigendum: Association between TAP1 gene polymorphisms and alopecia areata in a Korean population - Genet. Mol. Res. 14 (4): 18820-18827.

H.K. Kim1*, H. Lee1*, B.L. Lew2, W.Y. Sim2, Y.O. Kim3, S.W. Lee3, S. Lee4, I.H. Cho5, J.T. Kwon1 and H.J. Kim1,6 5Department of Convergence Medical Science, Brain Korea 21 Plus Program, and Institute of Korean Medicine, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea H.K. Kim1*, H. Lee1*, B.L. Lew2, W.Y. Sim2, Y.O. Kim3, S.W. Lee3, S. Lee4, I.H. Cho5, J.T. Kwon1 and H.J. Kim1,6 5Department of Convergence Medical Science, Brain Korea 21 Plus Program, and Institute of Korean Medicine, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea

Association study of polymorphisms between the Radixin gene and rheumatoid arthritis in a Korean population.

Radixin (RDX) is part of the ezrin-radixin-moesin (ERM) protein family. It functions as a membrane-cytoskeletal linker in actin-rich cell surface structures and is thought to be essential for cortical cytoskeleton organization, cell motility, adhesion, and proliferation. An increase in phosphorylated ERM in fibroblast-like synoviocytes contributes to rheumatoid arthritis (RA) synovial hyperplasia. We examined the genetic association between the RDX gene and RA in a Korean population. To identify the relationship between RDX gene polymorphisms and RA, we genotyped 2 single nucleotide polymorphisms (SNPs; rs11213326 and rs12575162) of RDX using a direct sequencing method in 296 RA patients and 493 control subjects. In this study, the 2 SNPs showed no association with RA disease susceptibility. However, further analysis based on clinical information of the RA patient group showed that the SNPs were associated with the erythrocyte sedimentation rate (ESR) in RA patients. These data suggest an association between RDX polymorphisms and the clinical features of RA patients, particularly the ESR.

The Gene Polymorphism of Angiotensinconverting Enzyme in Patients With Ischemic Stroke

Clinical Pharmacology & Therapeutics (1999) 65, 166–166; doi: