• International Journal of Oral Biology
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• 제35권4호
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• pp.185-190
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• 2010

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most prevalent pathogens in hospitals. To investigate cross contamination by this bacterium in both dental and medical settings, the pathogens that cause acute pyogenic infection and one of the major microbes responsible for nosocomial infection were isolated from health care providers, nurses and patients. We used VITEK II to measure drug sensitivity, and we further performed biochemical testing, coagulase serotype testing and pulse-field gel electrophoresis (PFGE) for isolated MRSA colonies. The isolation rate of Staphylococcus aureus from nasal swabs was 75.0% from dental health care providers and 18.8% from the medical health care providers. A total of 10 MRSA strains were isolated from 40 health care providers and 2 patients and the prevalent coagulase serotype from patients and health care providers was VII. The antimicrobial drug resistance and partial PFGE types of the isolated MRSA strains showed a similar pattern. These results suggest that MRSA may be one of the principal causes of nosocomial infection in dental and medical hospitals.

• Journal of Korean Neurosurgical Society
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• 제30권12호
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• pp.1381-1387
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• 2001

Objective : Endodermal sinus tumor or yolk sac tumor is an uncommon malignant germ-cell neoplasm. This tumor was originally described as a germ cell tumor of the ovary or the testis. Intracranial endodermal sinus tumor is extremely rare and usually develop in the pineal or suprasellar regions. The authors evaluated the effect of adjuvant therapy(chemotherapy combined with radiotherapy) and radical removal of intracranial endodermal sinus tumors. Material and Methods : Between 1996 and 2001, four patients of intracranial endodermal sinus tumor were diagnosed with tumor marker(AFP) and biopsy. Three patients were treated with surgical removal and chemotherapy with cisplatin($20mg/m^2$), etoposide($100mg/m^2$) and bleomycin($15mg/m^2$) as well as external beam radiation therapy. We compared the management problems for these tumors. Result : In all three patients the tumor size and the level of tumor marker decresed during initial adjuvant therapy. However, Tumors showed regrowth with elevated AFP of serum and CSF possibly related to delayed chemotherapeutic treatment or inadequate administration of chemotherapeutic drugs due to severe bone marrow suppression. An additional chemotherapy and external radiation therapy were given, but tumors could not be controlled with leptomeningeal seeding. Conclusion : Radiotherapy is considered to be less effective. The combination chemotherapy with PVB(cisplatin, vinblastine, bleomycine) or PE(cisplatin, etoposide) is considered to be value in prolongation of the survival rate. But the role of chemotherapy in this tumor has not yet been clarified due to bone marrow suppression and drug resistance. Further study with large series of this tumor is necessary to establish the optimal management.

• Journal of Medicine and Life Science
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• 제15권2호
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• pp.46-50
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• 2018

Cancer, a leading mortality disease following cardiovascular disease worldwide, has high incidence as one out of every four adults in Korea. It was known to be caused by several reasons including somatic mutation, activation of oncogene and chromosome aneuploidy. Cancer cells show a faster growth rate and have metastatic and heterogeneous cell populations compared to normal cells. Cancer stem cells, the most invested field in cancer biology, is a theory to explain heterogeneous cell populations of cancer cells among several characteristics of cancer cells, which is providing the theoretical background for incidence of cancer and treatment failure by drug resistance. Cancer stem cells initially explain heterogeneous cell populations of cancer cells based on the same markers of normal stem cells in cancer, in which only cancer stem cells showed heterogeneity of cancer cells and tumor initiating ability of leukemia. Based on these results, cancer stem cells were reported in various solid cancers such as breast cancer, liver cancer, and lung cancer. Breast cancer stem cells were first reported in solid cancer which had tumor initiating ability and further identified as anti-cancer drug resistance. There were several identification methods in breast cancer stem cells such as specific surface markers and culture methods. The discovery of cancer stem cells not only explains heterogeneity of cancer cells, but it also provides theoretical background for targeting cancer stem cells to complete elimination of cancer cells. Many institutes have been developing new anticancer drugs targeting cancer stem cells, but there have not been noticeable results yet. Many researchers also reported a necessity for improvement of current concepts and methods of research on cancer stem cells. Herein, we discuss the limitations and the perspectives of breast cancer stem cells based on the current concept and history.

• Journal of Veterinary Science
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• 제19권6호
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• pp.808-816
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• 2018

Bacterial biofilms have been demonstrated to be closely related to clinical infections and contribute to drug resistance. Berberine, which is the main component of Coptis chinensis, has been reported to have efficient antibacterial activity. This study aimed to investigate the potential effect of a combination of berberine with ciprofloxacin (CIP) to inhibit Salmonella biofilm formation and its effect on expressions of related genes (rpoE, luxS, and ompR). The fractional inhibitory concentration (FIC) index of the combination of berberine with CIP is 0.75 showing a synergistic antibacterial effect. The biofilm's adhesion rate and growth curve showed that the multi-resistant Salmonella strain had the potential to form a biofilm relative to that of strain CVCC528, and the antibiofilm effects were in a dose-dependent manner. Biofilm microstructures were rarely observed at $1/2{\times}MIC/FIC$ concentrations (MIC, minimal inhibition concentration), and the combination had a stronger antibiofilm effect than each of the antimicrobial agents used alone at $1/4{\times}FIC$ concentration. LuxS, rpoE, and ompR mRNA expressions were significantly repressed (p< 0.01) at $1/2{\times}MIC/FIC$ concentrations, and the berberine and CIP combination repressed mRNA expressions more strongly at the $1/4{\times}FIC$ concentration. The results indicate that the combination of berberine and CIP has a synergistic effect and is effective in inhibiting Salmonella biofilm formation via repression of luxS, rpoE, and ompR mRNA expressions.

• Tuberculosis and Respiratory Diseases
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• 제58권4호
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• pp.392-398
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• 2005

배 경 : 1995년 제7차 전국 결핵실태조사가 마지막으로 시행된 이 후 2000년 6월 결핵정보감시체계가 도입되었다. 결핵정보감시체계에서는 기존의 전국결핵실태조사에 포함된 균양성 유병율, 약제내성율 등 중요한 역학적 지표를 알 수 없는 한계를 가지고 있다. 본 연구의 목적은 1995년 12월과 2002년도 12월 국립마산결핵병원에 입원치료중인 환자의 임상양태를 조사 비교함으로 우리나라의 다제내성 결핵을 포함한 결핵실태추이의 한 단면을 알아보고자 함이었다. 방 법 : 2002년 12월 현재 국립마산결핵병원에 입원치료 중인 결핵환자 중 NTM으로 최종 확인된 6명을 제외한 331명을 대상으로 임상양태를 조사하고 이를 1995년에 보고된 자료와 비교조사 하였다. 결 과 : 1995년 자료와 비교할 때 평균연령은 3.6세 많았으며, 결핵치료 과거력과 이전 사용 약제 수는 각각 $2.0{\pm}1.7$회, $6.1{\pm}2.3$제에서 $1.7{\pm}1.8$회, $4.6{\pm}3.6$제로 감소하였다(각각 p<0.05, p<0.001). 전체적인 약제내성율은 비슷하였으나(81.0% vs 77.6%), 초회내성율과 초회다제내성율은 각각 10.5%와 2.4%에서 21.4%와 16.5%로 현저히 증가하였다(각각 p=0.012, p=0.001). 또한 1995년도에는 보건소에서 진단을 받은 경우가 65%였으나 2002년도에는 40.5%로 크게 감소하였다(p<0.001). 결 론 : 초회 내성율이 증가하고, 민간의료기관에서 진료하는 환자의 비중이 증가하는 등 우리나라의 결핵관리상황이 이전과 다르게 변해가고 있으므로 이에 대처할 수 있는 민간 및 공공의료기관이 협력할 수 있는 국가결핵관리프로그램의 수정 및 보완이 필요할 것으로 생각된다.

• 대한의생명과학회지
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• 제11권4호
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• pp.465-471
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• 2005

Ofloxacin has antimycobacterial activity that possibly contributes a pivotal role in the second-line drug regimens that are used for the treatment of multidrug-resistant tuberculosis. However, in some communities, the resistance rate of Mycobacterium tuberculosis to this agent is surging. Therefore, a rapid and accurate method that can be used to determine the resistance of M tuberculosis to the ofloxacin can be very useful for effective treatment of the patients. As an effort to develop such a method, this study was set up to reveal general types of mutations that are related to ofloxacin resistance of M tuberculosis. From previous studies, it has been well known that ofloxacin resistance is associated with mutations in a gene encoding the gyrase A subunit protein. In this study, we obtained 43 ofloxacin-resistant and 50 ofloxacin-susceptible M tuberculosis clinical isolates from Masan National TB Hospital, and sequences of DNA fragment of 320 bp, region of gyrA corresponding to the ofloxacin resistance-determining region were analyzed. In brief, the results showed that a total of seven mutation types were found at gyrA. Theses mutations were all clustered within nucleotides 2574 to 2586 of the gyrA gene (codons 88 to 94). Codon 94 was the most frequently substituted site. Twenty-four of the 43 isolates had mutations at this position resulting in a total of five different types of amino acid changes $(Asp{\to}Ala,\;Asp{\to}Gly,\;Asp{\to}His,\;Asp{\to}Tyr,\;and\;Asp{\to}Asn)$. Five isolates contained a mutation at codon 90 resulting $Ala{\to}Val$ change. Four isolates had mutations at codon 91 causing a $Ser{\to}Pro$ change at this site. Two isolates contained a mutation at codon 88 and each of them resulted in different types of amino acid changes $(Gly{\to}Cys,\;Gly{\to}Ala)$. On the other hand, polymorphic site at codon 95 was found in both ofloxacin-resistant and ofloxacin-susceptible isolates. From these results, we concluded that the rate of mutations present in gyrA among ofloxacin-resistant M. tuberculosis in Korea is similar to the general rates of mutations found throughout the world. Subsequently, an oligonucleotide probe was designed based on the results of sequence analysis and was used to develop a dot blot hybridization assay system to determine ofloxacin-resistance of M tuberculosis. To evaluate this probe, dot-blot hybridization was carried out using other 57 clinical isolates, and the results showed that the dot-blot hybridization assay is good for detecting sequence alterations atgyrA gene.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권1호
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• pp.49-57
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• 2020

Objectives: This study aimed to understand the nationwide patterns of antibiotic prescription after tooth extraction in adult patients. Materials and Methods: This study analyzed dental records from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) database on 503,725 tooth extractions performed in adults (≥19 years) during 2011-2015. Patient sex, age, household income, systemic disease (diabetes mellitus and hypertension), type of dental institution, region of dental institution, year of prescription, and type of tooth extraction procedure were considered. The antibiotic prescription rate and broad-spectrum antibiotic prescription frequency were analyzed using chi-squared tests. Factors affecting the prescription of broad-spectrum antibiotics were evaluated using multivariate logistic regression analysis. Results: The rate of antibiotic prescription after tooth extraction was 81.85%. Penicillin was most commonly prescribed (45.25%), followed by penicillin with beta-lactamase inhibitors (18.76%), metronidazole (12.29%), and second- to fourth-generation cephalosporins (11.52%). The proportion of broad-spectrum antibiotics used among all prescribed antibiotics was 45.88%. Conclusion: The findings of this study demonstrate that the rate of antibiotic prescription after tooth extraction is higher in Korea than in other countries. Furthermore, broad-spectrum antibiotics are used more frequently, which may indicate unnecessary drug prescription, an important contributor to antibiotic resistance.

• Journal of Veterinary Science
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• 제22권5호
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• pp.68.1-68.15
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• 2021

Background: Colistin and carbapenem-resistant bacteria have emerged and become a serious public health concern, but their epidemiological data is still limited. Objectives: This study examined colistin and carbapenem resistance in Escherichia coli and Salmonella from pigs, pig carcasses, and pork in Thailand, Lao PDR, and Cambodia border provinces. Methods: The phenotypic and genotypic resistance to colistin and meropenem was determined in E. coli and Salmonella obtained from pigs, pig carcasses, and pork (n = 1,619). A conjugative experiment was performed in all isolates carrying the mcr gene (s) (n = 68). The plasmid replicon type was determined in the isolates carrying a conjugative plasmid with mcr by PCR-based replicon typing (n = 7). The genetic relatedness of mcr-positive Salmonella (n = 11) was investigated by multi-locus sequence typing. Results: Colistin resistance was more common in E. coli (8%) than Salmonella (1%). The highest resistance rate was found in E. coli (17.8%) and Salmonella (1.7%) from Cambodia. Colistin-resistance genes, mcr-1, mcr-3, and mcr-5, were identified, of which mcr-1 and mcr-3 were predominant in E. coli (5.8%) and Salmonella (1.7%), respectively. The mcr-5 gene was observed in E. coli from pork in Cambodia. Two colistin-susceptible pig isolates from Thailand carried both mcr-1 and mcr-3. Seven E. coli and Salmonella isolates contained mcr-1 or mcr-3 associated with the IncF and IncI plasmids. The mcr-positive Salmonella from Thailand and Cambodia were categorized into two clusters with 94%-97% similarity. None of these clusters was meropenem resistant. Conclusions: Colistin-resistant E. coli and Salmonella were distributed in pigs, pig carcasses, and pork in the border areas. Undivided-One Health collaboration is needed to address the issue.

• 미생물학회지
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• 제45권2호
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• pp.99-104
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• 2009

본 연구에서는 2004년 1월부터 2008년 12월까지 인천지역 5개 종합 병 의원에 설사증상으로 입원 또는 내원한 환자의 대변에서 분리한 115주의 S. Enteritidis의 항생제 내성 및 다제내성 양상을 모니터링하였다. 그 결과, 가장 내성율이 높은 항생제는 nalidixic acid (54.8%)이었고, ampicillin (40.0%), ticarcillin (38.3%), chloramphenicol (20.9%), tetracycline (17.4%) 순이었다. 분리균의 91.3%는 1제 이상의 항생제에 내성이 있었다. 항생제 내성 유형을 살펴본 결과 nalidixic acid 단일 내성이 44.3%로 가장 높았으며, ampicillin-chloramphenicol-ticarcillin (11.3%) 및 ampicillin-ticarcillin (10.4%) 순이었다. 전체적으로 1제 내성이 51.9%, 2제 내성 18.2%, 3제 내성 14.5%, 4제 내성 5.8% 그리고 5제 이상 내성은 9.7%이었다.

• 한국임상약학회지
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• 제22권4호
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• pp.291-303
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• 2012

As respiratory tract infections (RTI) account for about 60% of all antibiotic prescriptions in outpatient care setting, there are significant concerns about emerging resistance that are largely due to the excessive or inappropriate use of antibacterial agents for viral respiratory infections. This study was aimed to develop retrospective drug utilization review (DUR) program of antibiotics for RTIs using Delphi methods. Retrospective DUR criteria of antibiotics for RTIs were identified based on clinical practice guidelines and opinion of experts. Expert panel members were clinical doctors and pharmacists and Delphi method was applied by survey on 16 members of panels. The claim data from Korean Health Insurance Review & Assessment (HIRA) were used to examine trends in outpatient antibiotic prescription between Janunary to December of 2008. As results, Quality index for RTI was assessed for the claim type, antibiotics use of quantity, duration, number and cost. Antibiotic prescription rate for RTIs, Defined Daily Dose (DDD), and duration of antibiotics use were more recognized as significant quality index by experts' opinion. Use of first line agents suggested by guidelines was low and duration of antibiotics use was shorter compared to the recommendations. Antibiotics were over prescribed for RITs. However, dose and duration of antibiotics were under-used.