• Tuberculosis and Respiratory Diseases
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• v.59 no.3
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• pp.266-271
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• 2005

Background : Ethambutol(EMB) is one of the first-line drugs included in short-course anti-tuberculosis therapy. The point mutations in embB gene have been speculated to be associated EMB resistance. However, detection of embB mutations at these positions have been observed in both EMB-susceptible isolates; thus, it remains controversial whether these mutations are associated with EMB resistance Methods : The 36 M. tuberculosis isolates were selected from clinical isolates which tested susceptible to EMB and resistant to at least one drug. DNA extracted from the isolates was analyzed by amplifying embB gene. The PCR products were purified and directly sequenced. We reviewed the history of past drug susceptibility test results. Results : Out of 36 EMB-susceptible strains, 3 strains (8.3%) had a mutation in codon 306 or 406 of the embB gene. These three strains had at least isoniazid resistance. They grew at 1.0 mcg/ml of EMB in Lowenstein-Jensen media. The patients of the strains were continuously smear-positive for over 3 years despite taking TB therapy. One strain had been EMB-resistant in past drug susceptibility tests. Conclusion : EMB-susceptible strains containing embB mutation may be caused by decreased viability in vitro test not by itself.

• Tuberculosis and Respiratory Diseases
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• v.58 no.2
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• pp.129-134
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• 2005

Background : Ethambutol (EMB) is one of important first-line drug in the treatment of tuberculosis. Molecular techniques to detect embB gene mutations have been considered as an method to define the EMB resistance. We investigated the mutation rate within embB gene among EMB resistant strains using reverse hybridization techniques. Methods : We made 11 probes that had wild or mutated sequences containing codons 306, 406, or 497 within embB gene respectively. These probes were reverse-hybridized with PCR products amplified from embB gene which were isolated from 149 ethambutol resistant strains and 50 pan-susceptible strains. Results : Out of 149 ethambutol resistant strains, one hundred (67.1%) had mutation at least one base at codon 306, 406, or 497 in embB gene. Mutation at codon 306, 406, 497 were demonstrated in 75 (50.3%), 16 (10.7%), and 13 strains (8.7%) respectively. There were four strains that showed multi-mutation at codon 306 and codon 406 simultaneously. A high proportion (8.1%) had single mutation at codon 406. There was no mutation observed in embB gene among 50 pan-susceptible strains. Conclusion : Reverse hybridization will be useful technique for detection of gene mutation correlated to ethambutol resistance.

• 보건세계
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• v.56 no.6
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• pp.19-23
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• 2009

외래에서 흔히 이용하는 결핵 진단법으로는 객담 도말과 배양검사, 엑스선 검사가 있다. 일단 활동성 결핵으로 진단되면 환자의 과거력 등을 참조하여 치료를 하게 되는데, 초치료인 경우 아이나, 리팜핀, 에탐부톨, 피라진아마이드를 이용한 6개월 단기 초치료 처방으로 치료를 한다. 4제 처방의 효과는 강력하여 규칙적으로 약을 복용한다면 대부분 완치되며, 완치 판정은 치료 중 추구 객담검사를 이용한다. 대부분의 환자들은 진단, 치료에 어려움이 없지만 실제 외래 치료시에는 진단, 치료에서 어려운 문제가 발생하기도 한다. 이에 외래에서 부닥칠 수 있는 상황과 적절한 대처법을 알아보기로 한다.

• Journal of Pharmaceutical Investigation
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• v.18 no.4
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• pp.175-180
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• 1988

The role and effect of aluminum tristearate in microencapsulation were investigated based on the dispersion system of ethambutol hydrochloride in acetone-liquid paraffin. Eudragit RS was used as a wall-forming material. Eudragit RS microcapsules prepared using aluminum tristearate were uniform, free-flowing particles. The phase diagram of ethambutol hydrochloride-Eudragit RS-aluminum tristearate indicated that spherical microcapsules ranging from 250 to 1400 ${\mu}m$ in diameter could be prepared only in a very limited region. Instrumental analysis using an energy dispersive-type X-ray microanalyser and a scanning electron microscope showed that aluminum tristearate was localized near the surface of microcapsules. From these results, it was presumed that aluminum tristearate reduced the phase tension between Eudragit microcapsules and liquid paraffin. The dissolution rates of ethambutol hydrochloride from Eudragit RS microcapsules were consideraly lower than those from ethambutol hydrochloride powders and decreased as the amount of aluminum tristearate decreased.