• Tuberculosis and Respiratory Diseases
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• 제80권3호
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• pp.255-264
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• 2017

Background:N-acetyl transferase (NAT) inactivates the pro-drug isoniazid (INH) to N-acetyl INH through a process of acetylation, and confers low-level resistance to INH in Mycobacterium tuberculosis (MTB). Similar to NAT of MTB, NAT2 in humans performs the same function of acetylation. Rapid acetylators, may not respond to INH treatment efficiently, and could be a potential risk factor, for the development of INH resistance in humans. Methods: To understand the contribution of NAT of MTB and NAT2 of humans in developing INH resistance using in silico approaches, in this study, the wild type (WT) and mutant (MT)-NATs of MTB, and humans, were modeled and docked, with substrates and product (acetyl CoA, INH, and acetyl INH). The MT models were built, using templates 4BGF of MTB, and 2PFR of humans. Results: On the basis of docking results of MTB-NAT, it can be suggested that in comparison to the WT, binding affinity of MT-G207R, was found to be lower with acetyl CoA, and higher with acetyl-INH and INH. In case of MT-NAT2 from humans, the pattern of score with respect to acetyl CoA and acetyl-INH, was similar to MT-NAT of MTB, but revealed a decrease in INH score. Conclusion: In MTB, MT-NAT revealed high affinity towards acetyl-INH, which can be interpreted as increased formation of acetyl-INH, and therefore, may lead to INH resistance through inactivation of INH. Similarly, in MT-NAT2 (rapid acetylators), acetylation occurs rapidly, serving as a possible risk factor for developing INH resistance in humans.

• Biomolecules & Therapeutics
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• 제10권3호
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• pp.193-199
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• 2002

The arylamine N-acetyltransferases (NATs) are a family of enzymes that N-acetylate mylhydrazines and arylamines through transfer of an acetyl group from acetyl coenzyme A. This activity was found to vary among individuals as a Mendalian trait and the basis of the genetic differences in human NAT activity is one of the best of the genetic studied examples of pharmacogenetic variation. The classical N-acetylation polymorphism is regulated at the NAT2 locus, which segregates individuals into rapid, intermediate, and slow acetylator phenotypes. In this study, the relationship between NAT2 activity phenotype using HPLC:UV assay for the determination of dapsone and monoacetyldapsone in plasma and NAT2 genotype by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) was investigated in the F2 hybrid (Fischer 344 vs Wistar-Kyoto) rats. Three Common mutant alleles at the NAT2 gene locus have been identified in the F2 generation progeny of Fischer 344 rats as raid acetylator and Wistar-Kyoto rats as slow acetylator segregated into three modes (low, intermediates, and high) with simple Mendelian inheritance. The metabolic activity of NAT2 of the intermediate and rapid acetylators is significant1y greater than slow acetylator, but the metabolic activity of rapid acetylator is not significantly different from Intermediate type. Therefore, we could observe that complete trimodal NAT2 genotypic alleles and incomplete trimodal NAT2 metabolic phenotypic distribution in tile F2 hybrid rats. These observations suggest that the relationships between NAT2 genotype and metabolic phenotype exists and F2 hybrid (Fischer 344: Wistar-Kyoto) animal models about NAT2 polymorphism might be applied in the toxicity and pharmacogenetic studies of arylamine drugs and carcinogens.

• Journal of Pharmaceutical Investigation
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• 제9권3호
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• pp.1-8
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• 1979

The main route of metabolism of isonicotinic acid hydrazid (INH) in man is its conjugation with acetyl coenzyme A to form acetyl-INH. The reaction is catalyzed by an N-acetyl transferase in the liver. The acetylated drug can be excreted by the kidney more efficiently than INH, and the biological half-life of the drug in the body depends upon how rapidly the drug can be acetylated. This report measured the concentration of INH in the blood of 147 individuals 6 hours after they received a standard dose (9.8mg/kg) and plotted the data as a frequeney distribution hiotogram. There was bimodality, with a mean for one subpopulation at approximately $0.6{\sim}0.8\;mcg/ml.$, and a mean for the other subpopulation between 2.8 and 4.0mcg/ml. As might be expected slow acetylators of INH are more likely to develop a cumulative toxicity to the drug. The principle ,toxicity to INH is a peripheral neuritis but this adverse effect can be prevented by given extra pyridoxin to the patients, and the vitamin does not alter the antitubercular activity of INH. This report carried out that pyridoxine does not alter the ratio of free INH to the total INH in blood.

• Journal of Preventive Medicine and Public Health
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• 제31권2호
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• pp.275-284
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• 1998

1996년 3월부터 1996년 12월까지 충북대학교병원 비뇨기과에 입원하여 치료를 받은 방광암 환자 67명과 암 아닌 다른 질환을 가진 대조군 67명을 대상으로 흡연, 음주, 직업력 등을 포함한 생활 습관과 NAT2와 GSTM1, 그리고 GSTT1 유전자 다형성 양상을 조사하여 다음과 같은 결론을 얻었다. 1. NAT2 다형성 분포는, 환자군이 slow, intermediate, rapid acetylator가 각각 3.0%, 38.8%, 58.2%, 그리고 대조군이 7.6%, 40.9%, 51.5%였으며, NAT2의 활성과 방광암 위험도 사이의 관련성은 유의하지 않았다($\chi^2_{trend}=1.18$, P-value>0.05). 2. GSTM1 결손은 환자군의 68.7%, 대조군의 49.3%에서 확인되었으며, OR(95% 신뢰구간)이 2.23(1.12-4.56)으로, 방광암 발생의 위험인자로 나타났다. 3. GSTT1은 환자군의 26.9%,그리고 대조군의 43.3%에서 결손이 있는 것으로 나타나서, GSTT1 결손은 방광암에 대하여 보호효과가 있는 것으로 관찰되었다(OR: 0.48, 95% 신뢰구간: 0.23-0.99). 4. 흡연 여부는 방광암의 발생에 유의한 영향을 미치지 않는 것으로 나타났는데(OR=1.85, 95% CI: 0.85-4.03), 이는 환자군과 대조군의 흡연률이 모두 높기 때문으로 판단된다. 5. 그 외, 음주력, 직업력, 수혈 여부, 그리고 피임시술의 과거력 등의 요인들은 방광암 발생과 유의한 관련성이 없는 것으로 나타났다.

• Tuberculosis and Respiratory Diseases
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• 제60권1호
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• pp.44-48
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• 2006

연구배경 : Isoniazid (INH)에 관한 국내 폐결핵 진료지침은 외국의 지침들(300 mg/일)과 달리 체중이 50kg 이상인 경우 400 mg/일을 권장량으로 제시하고 있으나 근거가 없는 실정이다. 따라서 국내에서 1차 4제요법 치료시 INH 300 mg/일과 400 mg/일 처방에 따른 차이를 확인하기 위해 본 연구를 시행하였다. 방 법 : 폐결핵으로 진단받고 표준 4제치료를 시행한 환자 중 50kg 이상이고 모든 1차약제 감수성이 확인된 환자를 INH 300 mg/일과 400 mg/일 군으로 나누어 비교하였다. 결 과 : 2003년 4월부터 2005년 3월까지 상기 조건을 만족하는 환자 중 INH 300 mg을 사용한 군(300군)은 123명, 400 mg을 사용한 군은 128명(400군)이었다. 나이, 남녀비, 체중, 결핵치료력, AFB 도말 양성률, 공동병소 동반율에서 300군 및 400군 간 유의한 차이는 없었다. 300군 및 400군에서 치료 완료율은 90%:80%였고, 전체 부작용에 의한 약제 변경률은 9.0%:13.7%, 간독성에 의한 약제 변경률은 2.7%:7.8%로 유의한 차이가 없었다. 추적 관찰 기간이 짧아 재발률은 분석되지 않았다. 결 론 : INH 300군과 400군 사이에 치료성적 및 약제 부작용면에서 차이가 없어서 50kg 이상의 결핵환자의 표 준처방시 INH 300mg이 유용하다고 사료되나 향후 재발률의 비교 연구가 필요하다.