• Journal of Pharmaceutical Investigation
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• 제33권4호
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• pp.305-310
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• 2003

One of the possible mechanisms of multi-drug resistance found in cancer cells is the over-expression of P­glycoprotein (P-gp). Studies have shown that compounds in plants including vegetables and fruits not only have anticancer activities but may also modulate P-gp activity. The effect of flavonoids and organic isothiocyanate on P-gp activity was studied in human uterine sarcoma cell lines, MES-SA (sensitive) and MES-SA/DX5 (resistant) cells. The accumulation of daunomycin (DNM), a P-gp substrate, was approximately 10 times greater in the sensitive cell as compared to the resistant cells over the entire time course (up to 2 hours). The positive control, verapamil increased the two hour accumulation of DNM while quercetin decreased that of DNM in the resistant cells. 1-Naphtyl-isothiocyanate (NITC) showed no effect on the two hour accumulation of DNM. The $IC_{50}$ values for DNM in the resistant cells was about 20 times higher than that observed in the sensitive cells $(10.1{\pm}1.7\;{\mu}M\;vs.\;0.58{\pm}0.28\;{\mu}M)$. Verapamil reduced the $IC_{50}$ value for DNM whereas flavonoids (quercetin and fisetin) increased those for DNM in the resistant cells.

• Tuberculosis and Respiratory Diseases
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• 제84권1호
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• pp.74-83
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• 2021

Background: This study compared the treatment outcomes of patients with multidrug-resistant tuberculosis (MDR-TB) before and after the implementation of public-private mix (PPM). Factors affecting treatment success were also investigated. Methods: Data from culture-confirmed pulmonary MDR-TB patients who commenced MDR-TB treatment at Pusan National University Hospital between January 2003 and December 2017 were retrospectively reviewed. Patients were divided into two groups in terms of PPM status: pre-PPM period, patients who commenced MDR-TB treatment between 2003 and 2010; and post-PPM period, patients treated between 2011 and 2017. Results: A total of 176 patients were included (64 and 112 in the pre- and post-PPM periods, respectively). 36.9% of the patients were resistant to a fluoroquinolone or a second-line injectable drug, or both. The overall treatment success rate was 72.7%. The success rate of post-PPM patients was higher than that of pre-PPM patients (79.5% vs. 60.9%, p=0.008). Also, loss to follow-up was lower in the post-PPM period (5.4% vs. 15.6%, p=0.023). In multivariate regression analysis, age ≥65 years, body mass index ≤18.5 kg/m², previous TB treatment, bilateral lung involvement, and extensively drug-resistant (XDR)- or pre-XDR-TB were associated with poorer treatment outcomes. However, the use of bedaquiline or delamanid for ≥1 month increased the treatment success. Conclusion: The treatment success rate in MDR-TB patients was higher in the post-PPM period than in the pre-PPM period, particularly because of the low rate of loss to follow-up. To ensure comprehensive patient-centered PPM in South Korea, investment and other support must be adequate.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3782-3786
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• 2013

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and that accounts for 85% of lung cancer patients. Although several EGFR-targeted drugs have been developed in the treatment of NSCLC, the clinical efficacy of EGFR-targeted drugs in NSCLC is limited by the occurrence of drug resistance. In this regard, Hsp90 represents great promise as a therapeutic target of cancer due to its potential to simultaneously disable multiple signaling pathways. In this study, we discovered that a natural product, flavokawain B disrupted Hsp90 chaperoning function and impaired the growth of gefitinib-resistant non-small cell lung cancer (H1975). The result suggested that flavokawain B could serve as a potential lead compound to overcome the drug resistance in cancer chemotherapy.

• Pediatric Infection and Vaccine
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• 제16권1호
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• pp.6-12
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• 2009

There are relatively few novel antimicrobial agents despite the dramatic increase in antimicrobial resistance and multiple drug resistance of clinical isolates worldwide. Vancomycin is still the most widely used antibiotic for treating resistant Gram-positive coccal infections in children, especially for methicillin-resistant Staphylococcus aureus. For children with Gram-positive coccal infections where vancomycin is not effective or older therapeutic agents cannot be tolerated, linezolid, quinupristin-dalfopristin or daptomycin may be useful in the appropriate clinical setting. For Gram-negative bacterial infections, new carbapenems await clinical application. Tebipenem pivoxil is a novel oral carbapenem undergoing clinical trials for acute otitis media in pediatric patients. Antiviral drug development is now progressing at the pace of antibiotic development 30 years ago. Newer antiviral agents used for the treatment of herpes viruses and hepatitis C virus infections in children are included in this review.

• Journal of Korean Neurosurgical Society
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• 제62권3호
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• pp.328-335
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• 2019

Epilepsy is one of the most common chronic neurological disorder affecting 6-7 per 1000 worldwide. Nearly one-third of patients with newly diagnosed epilepsy continue to have recurrent seizures despite adequate trial of more than two anti-seizure drugs : drug-resistant epilepsy (DRE). Children with DRE often experience cognitive and psychosocial co-morbidities requiring more urgent and aggressive treatment than adults. Epilepsy surgery can result in seizure-freedom in approximately two-third of children with improvement in cognitive development and quality of life. Understanding fundamental differences in etiology, co-morbidity, and neural plasticity between children and adults is critical for appropriate selection of surgical candidates, appropriate presurgical evaluation and surgical approach, and improved overall outcome.

• Natural Product Sciences
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• 제28권3호
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• pp.93-104
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• 2022

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious threat to the global healthcare system. Ineffective and resistance to antibiotic treatments have increased morbidity and mortality rates worldwide. New and effective antibiotics are needed to combat against bacterial resistance. Endophytic fungi are crucial reservoirs of novel bioactive metabolites. In particular, the secondary metabolites show promising therapeutic potential, notably, antibacterial. This review discussed the emerging potential of endophytic fungi as anti-MRSA agents. The ecological sources of endophytic fungi were discussed with the synthesis of bioactive metabolites. The mode of antibacterial actions was elucidated to give a better understanding of the mechanisms involved. This review may serve as an important reference for future discovery and developments of anti-MRSA agents from endophytic fungi.

• Journal of Microbiology and Biotechnology
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• 제34권7호
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• pp.1365-1375
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• 2024

The rise of Candida auris, a multidrug-resistant fungal pathogen, across more than 40 countries, has signaled an alarming threat to global health due to its significant resistance to existing antifungal therapies. Characterized by its rapid spread and robust drug resistance, C. auris presents a critical challenge in managing infections, particularly in healthcare settings. With research on its biological traits and genetic basis of virulence and resistance still in the early stages, there is a pressing need for a concerted effort to understand and counteract this pathogen. This review synthesizes current knowledge on the epidemiology, biology, genetic manipulation, pathogenicity, diagnostics, and resistance mechanisms of C. auris, and discusses future directions in research and therapeutic development. By exploring the complexities surrounding C. auris, we aim to underscore the importance of advancing research to devise effective control and treatment strategies.

• 한국동물위생학회지
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• 제32권1호
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• pp.61-76
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• 2009

At the present study, it was aimed to explore the molecular genetic characterization of multiple antimicrobial resistant Salmonella spp. isolates from pigs and cattle. A total of 138 Salmonella Typhimurium (S. Typhimurium) isolates were typed with phage, among them, 83.3% of S. Typhimurium tested could divide into a 10 phage types. Definitive type 193 (DT193) (25.4%) and DT195 (24.6%) were exhibited as the dominant types. DT104 and U302 were found from pigs and cattle. On the other hand, S. Enteritidis had 6 phage types, of them, phage type 21 (PT21) and PT11b were the popular types. In the plasmid profiles, 135 of S. Typhimurium isolates were exhibited 1 to 6 plasmid bands which molecular weight ranged from 90 to 2kb. 35 isolates (25.4%) harbored a 90kb plasmid which is thought to be the serotype specific virulence plasmid. Two of twenty five S. Enteritidis had common plasmids at 2 and 1.5kb. With multiplex polymerase chain reaction, virulence genes (invA and spvC) were detected from all Salmonella spp. from 167 of S. Typhimurium, S. Enteritidis and chloramphenicol resistant S. Schwarzengrund, but some drug resistant genes, such as PSE-1, cml/tetR and flo were not determined but other drug resistant genes, for example TEM and int were found. The detection rates of spvC, TEM and int gene was 35.3%, 29.3% and 72.5%, respectively. The TEM gene was highly popular in S. Typhimurium, which was detected from ampicillin and amoxicillin resistant strains as 95.9%. int gene was able to detect from all the isolates identified as multidrug resistsnt (MDR), particularly DT193 was thought as the most prevalent virulence and multidrug resistance isolate. The major plasmid profile and drug resistance pattern of DT193 were 90, 40, 10.5, 6.3, 3.0kb and ACCbDNaPSSuT, respectively. MDR was commonly found in other phage types, particularly DT104, U302 and DT203.

• 대한수의학회지
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• 제16권2호
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• pp.159-163
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• 1976

One hundred and sixty one Escherichia coli strains isolated from 24 swine (11 swine fed with feedstuffs containing 7.5mg/kg of tetracycline and 13 swine not received antibiotic) were studied for the drug resistance and distribution of R factors. About 42 per cent of E. coli strains isolated from pigs of a herd fed with tetracycline (TC)-containing feeds were resistant to TC, streptomycin(SM), sulfisomidine(SA), ampicillin (AP) and kanamycin (KM), alone or in combination thereof, but none of the swine not receiving antibiotic containing feedstuffs excreted E. coli resistant to these drugs, Among resistant strains, 18.2% were found to be singly resistant to TC, whereas 81.8% were resistant to two or more antibiotics. The most common pattern was the triple resistant to TC, SM and SA(30.3%), and follolwed by double ones to TC and SM(24.2%). About one half of resistant strains carried R factors which were tranferable to the recipients by conjugation. In spite of feeding with feedstuffs containing only TC, high incidences of multiple resistance and R factors were observed in the E. coli isolated from these swine.

• Tuberculosis and Respiratory Diseases
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• 제51권5호
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• pp.416-425
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• 2001

연구배경 : 지역 3차 진료기관으로 의뢰된 폐결핵환자의 약제내성률을 과거의 치료력, 흉부 방사선 소견의 차이에 따라서 조사하고, 향후 치료에 도움이 되는 지표를 알아보고자 하였다. 방 법 : 1997년 5월부터 2000년 6월까지 객담 배양검사 양성으로 폐결핵으로 진단받는 138명의 환자를 대상으로 결핵약제 내생검사를 후향적으로 조사하여 결핵 약제내성률과 과거 치료 병력, 흉부 방사선 사진상 폐침범 정도와 공동 유무 등의 관계를 조사하였다. 결 과 : 총 138명의 환자 중 39.9%(55 명)가 1 지 이상 약제 내성을 보였으며 24.6%(34명)가 INH와 RFP에 동시내성올 보였다. 과거 받지 않았던 초치료 환자가 91명이었으며, 이 중 한가지 이상 약제에 대한 내성률이 22%(20 명)이었으며, 다제내성률은 9.9%(9명)였다. 재치료 환자는 47명이었으며 그중 74.5%(32명)가 약제내성 이었으며 다제내성률은 53.2%(25명)이었다. INH에 대한 약제내성은 34.1%로 가장 높았고 RFP 26.1%, PZA 16.7%, EMB 14.5%, SM 12.3%, 및 PAS 8.7% 순이었다. 일차 약제인 INH, RFP, EMB 및 PZA에 대한 약제내성률은 과거 치료 병력이 있는 경우에 의미있게 높았다(p<0.05). 이차약제인 PAS, KM, OFX도 내성률이 재치료군에서 의미 있게 높았다(p<0.01). 흉부방사선에 의한 중증도 분류에서 중증에서 공동이 있는 환자군에서 INH 및 RFP의 풍시 내성률이 의미있게 높은 결과를 보였다(p<0.05). 다변량 분석에서 INH, RFP, PZA 및 INH와 RFP의 내성은 재치료군에서 odds ratio가 각각 9.43, 9.09, 8.93 및 10.53으로 내성률이 의미 있게 높았다(p<0.01). 공동이 있을 경우 odds ratio는 단변량분석시는 INH, RFP 및 INH와 RFP에 내생률이 의미 있게 높았으나 다변량분석시는 RFP, INH와 RFP만 의미있게 보였다. 결해의 방사선 침범정도에 따른 odds ratio는 RFP, INH와 RFP이 의미 있게 높은 결과를 보였으나, 다변량분석시는 의미있는 차이가 없었다. 결 론 : 초치료 또는 재치료 결핵환자들의 약제내성률은 전국 평균치보다 훨씬 높았다. 다제내성의 빈도도 높았다. 약제내성을 예측하는 지표로서 과거치료병력 뿐 아니라 흉부 방사선 사진상의 공동의 유무도 유용한 것으로 생각되지만, 흉부 방사선 사진상의 폐 침법 정도의 약제내성 예측능에 대해서는 좀 더 광범위한 환자를 대상으로 하는 추후 연구를필요로 한다.