• 약학회지
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• 제40권6호
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• pp.697-704
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• 1996

Quinolone derivatives, SJ5b (ethyl 5,12-dihydro-5-dihydro-5-oxobenzoxazolo[3,2-a]quinoline-6-carboxylate) and SQ7b (3-fluoro-2-(4-methylpiperazin-1-yl)-5.12-dihydro-5-oxobenzoxa zolo[3,2-a]quinoloine carboxylic acid) showed in vitro cytotoxicities against various tumor cell lines. SJ5b and SQ7b completely inhibited the DNA relaxation activities of human placental topoisomerase II at the concentration of 15.63 and 1.95 ${\mu}$g/ml, respectively. However, unlike etoposide which stabilize the topoisomerase II-DNA complex, SQ7b did not cause topoisomerase II-mediated DNA cleavage and SJ5b weakly stabilized the topoisomerase II-DNA cleavable complex. Through both experiments. DNA relaxation assay by the increment of topoisomerase II concentration and DNA unwinding assay, it was shown that SJ5b and SQ7b did not interact with topoisomerase II itself but bound to DNA. Therefore, it was concluded that DNA binding of SJ5b and SQ7b caused the inhibition of topoisomerase II related to DNA relaxation but no or very weak stabilization of topoisomerase II-DNA cleavable complex. In addition, SJ5b and SQ7b prevented whole cell nucleic acid syntheses in HL60 cells.

• Archives of Pharmacal Research
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• 제19권5호
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• pp.353-358
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• 1996

E. coli 11 and E. coli 101, clinical isolates of Escherichia coli were resistant to various quinolones, especially MICs to norfloxacin of both strains were higher than 100 mg/ml. In the presence of carbonyl cyanide m-chlorophenylhydrazone, a proton gradient uncoupler, norfloxacin uptake in both strains was increased, suggesting that an efflux system play an important role in the norfloxacin resistance. Outer membrane proteins of the susceptible and resistant strains which could affect the route of norfloxacin entry into cells were different. When quinolone resistance determining region(QRDR) of gyrA was amplified using PCR and cut with Hinf I, QRDR in the susceptible strain yielded two fragments while QRDRs in E. coli 11 and E. coli 101 yielded only one uncut fragment. When DNA sequence of QRDR was analyzed, there were two mutations as Ser-83 and Asp-87 in both resistant strains. these residues were changed to Leu-83 and Asn-87, respectively. These results showed that the norfloxacin resistance of E. coli 11 and E. coli 101 was resulted from multiple changes-an altered DNA gyrase A subunit, a change in route of drug entry, and reduction in quinolone concentration inside cells due to an efflux system.

• Biomolecules & Therapeutics
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• 제4권2호
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• pp.184-189
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• 1996

General pharmacological studies of LB20304a (a mesylate salt form of a new quinolone antibiotic LB20304 following oral administration of 300 mg/kg and 1000 mg/kg, almost maximum tolerance dose in mice and rat, respectively, were performed in terms of effects on general behaviour, central nervous system, gastrointestinal system, and blood coagulation system in mice and rats. With regards to general behaviour of mice, at oral dose of 300 mg/kg, LB20304a reduced muscle tone and locomotor activity. In terms of CNS, at oral treatment of 300 mg/kg, LB20304a showed some analgesic effects in mice, and oral dose of 1000 mg/kg caused drop in normal body temperature of rat, while it enhanced the pentylenetetrazole-induced clonic convulsion to tonic convulsion and/or death in mice at the doses of unto 300 mg/kg. In addition, LB20304a increased hexobarbital-induced sleeping time two and three times in mice at oral doses of 20 mg/kg and 300 mg/kg, respectively. Rota-rod and traction test in mice were not influenced by the dose of 300 mg/kg and 200 mg/kg, respectively. LB20304a reduced gastric secretion of rat at dose of 1000 mg/kg, and increased intestinal motility of mice at dose of 300 mg/kg. In rats, blood coagulation index, such as PT (prothrombin time) and aPTT (activated partial thromboplastin time) were not affected by the treatment of upto 1000 mg/kg of LB 20304a.

• 대한임상검사과학회지
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• 제56권2호
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• pp.115-124
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• 2024

플루오로퀴놀론(fluoroquinolone, FQ) 항균제 내성을 갖는 황색포도알균(Staphylococcus aureus)의 출현 및 확산으로 감염증 치료에 어려움을 겪고 있다. 이 퀴놀론 내성 황색포도알균(quinolone resistant S. aureus, QRSA) 에 대한 분자역학적 특성을 조사하여 치료에 도움을 주는 자료를 만들고자하였다. 대전광역시 소재 1개 종합병원에서 혈액배양 검체에서 분리된 QRSA 균주를 대상으로 mecA와 SCCmec 유전자형 분석에 따른, gyrA, gyrB 유전자의 돌연변이를 조사하였다. Ciprofloxacin 내성균주는 SCCmec typing에서 II형이 44개로 73%, IVa형이 5개로 8%, III와 V형이 1개로 2%, nontypeable 균주가 11개로 18%, levofloxacin, moxifloxacin은 II형이 44개로 73%, IVa형이 5개로 8%, III와 V형이 1개로 2%, non typeable 균주가 10개로 17%의 결과를 보였다. gyrA와 gyrB 영역 모두에서 58개로 96.7%, levofloxacin은 56개로 93.3%, moxifloxacin에는 57개로 95%를 나타냈다. QRSA 균주에 대한 gyrA와 gyrB의 돌연변이는 각각 6개씩 12개의 돌연변이가 확인되었다. 연구 대상 QRSA의 FQ 항균제의 내성률은 약 98%를 나타냈고, QRSA 균주에 대한 gyrA와 gyrB의 돌연변이는 각각 6개씩 12개의 돌연변이가 확인되었다.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1998년도 한국생물과학협회 학술발표대회
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• pp.308.2-308
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• 1998

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2002년도 학술발표대회
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• pp.30-30
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• 2002

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1997년도 춘계학술대회
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• pp.33-39
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• 1997

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2008년도 International Meeting of the Microbiological Society of Korea
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• pp.38-38
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• 2008

• 한국보건교육건강증진학회:학술대회논문집
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• 한국보건교육건강증진학회 2005년도 제30회 보건학종합학술대회
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• pp.179-198
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• 2005

• Bulletin of the Korean Chemical Society
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• 제19권8호
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• pp.819-821
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• 1998