• Radiation Oncology Journal
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• v.19 no.1
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• pp.16-20
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• 2001

Purpose : To evaluate the effectiveness and tolerance of the postoperative radiation therapy for patients with Stage III thymoma and to define the optimal radiotherapeutic regimen Materials and Methods : We retrospectively analyzed the records of 24 patients with Stage III thymoma who were referred for postoperative radiation therapy in our institution from June, 1987 to May, 1999. Surgical therapy consisted of total resection in one patient, subtotal resection in seventeen, and biopsy alone in six patients. Age of the patients was ranged from 20 to 62 years with mean age of 47 years. Male to female ratio was 14 to 10. Radiation therapy was delivered with linear accelerator producing either 6 MeV or 10 MeV photons. The irradiated volume included anterior mediastinum and known residual disease. The supraclavicular fossae were not irradiated. The delivered total dose was ranged from 30 to 56 Gy. One patient received 30 Gy and eighteen patients received minimum of 50 Gy. Follow up period was ranged from 12 months to 8 years with median follow up of 40 months. Results : The overall local control rate for entire group of patients was $67\%$ at 5 years. The cumulative local failure rates at one, three and five year were $18\%,\;28\%\;and\;33\%$, respectively. In patients treated with subtotal resection and biopsy alone, local control rate was $76\%\;and\;33\%$, respectively. The actuarial observed survival rate at 5 years was $57\%$, and actuarial adjusted survival at 5 years was $72\%$. The difference between 5 year survival rates for patients treated with subtotal resection and biopsy alone was not statistically significant $(62\%\;vs\;30\%)$. Conclusion : We might conclude that postoperative radiation therapy was safe and effective treatment for patients with Stage III thymoma. Postoperative radiation therapy is recommended in cases where tumor margin is close or incomplete resection is accomplished.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.286-294
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• 2004

Between 1997 and 1998 in Korea, 56 isolates of Escherichia coli were obtained from pig suffering diarrhea. Among those, 38 isolates that showed the hemolytic activity, antimicrobial resistance, and toxin production were studied. Among 38 isolates, thirty-six isolates $(94.7\%)$ were resistant to tetracycline, 27 isolates $(71.0\%)$ were resistant to ampicillin, 26 isolates $(68.4\%)$ were resistant to chloramphenicol, and 21 isolates $(55.2\%)$ were resistant to trimethoprim, while none was resistant to aztreonam, amikacin, and norfloxacin. Among these iso­lates, 21 isolates $(55.3\%)$ were multiple drug resistant to at least four different class antimicrobial agents. Extended spectrum $\beta-lactamase$ producing isolates were not detected in the double disk synergy test. In these hemolytic Escherichia coli, heat-stable enterotoxin $(89.5\%)$ was the most prevalent toxin, followed by vero­toxins $(47.4\%),$ and then heat-labile enterotoxin $(31.6\%).$ Except 8 isolates $(21.0\%)$ which produced ST only, 12 isolates $(31.6\%)$ produced ST and LT, 13 isolates $(34.2\%)$ produced ST, VT, and VTe, and 5 isolates $(13.2\%)$ produced VT and VTe. However, none produced all 4 types of toxin, simultaneously. The predominant serotype could not be determined by the agglutination method. Sixteen isolates $(42.1\%)$ were strongly adhered to T-24 bladder cell and 17 isolates $(44.7\%)$ were to Caco-2 intestinal cell. Especially, 11 strains $(28.9\%)$ were evaluated as strongly adhesive to both T-24 cells and Caco-2 cells. Genes for toxin and the antimicrobial resistance were transferred to clinical isolates of Escherichia coli from human urine by the filter mating method. Results suggest the possibility that antimicrobial resistance and toxin can be transferred from animals to humans by direct con­tact of resistant bacteria as well as gene transfer, although there was no correlation between toxin production, adherent activity, and antimicrobial resistance among hemolytic E. coli isolated from pig suffering diarrhea.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.295-301
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• 2004

Recently, the rapid increase and global spread of extended-spectrum $\beta-lactamase$ producing clinical isolates has become a serious problem. The incidence of extended-spectrum $\beta-lactamase$ producing clinical isolates of Escherichia coli in Korea and susceptibility to antimicrobial agents were investigated. Total 233 isolates of E. coli were obtained from urine from hospitalized patients in Guro hospital, Korea University in 2001. One hun­dred and eighty four isolates $(78.9\%)$ were resistant to ampicillin, 80 isolates $(34.3\%)$ were resistant to ceph­alothin, 93 isolates $(39.9\%)$ were resistant to gentamicin, and 64 isolates $(27.5\%)$ were resistant to norfloxacin. Among 233 isolates, 17 isolates $(7.3\%)$ were positive as determined by the double disk synergy test. When min­imal inhibitory concentrations were assayed with additional 6 antimicrobial agents, 13 isolates $(76.5\%)$ were multi-drug resistant to at least four different class antimicrobial agents. Extended-spectrum $\beta-lactamase$ were characterized with isoelectric focusing gel electrophoresis and DNA sequencing. They were TEM-1 in 5 iso­lates, TEM-15 in 1 isolate, TEM-20 in 1 isolate, TEM-52 in 4 isolates, TEM-1 and AmpC in 2 isolates, TEM-1 and OXA-30 in 1 isolate, TEM-1 and OXA-33 in 1 isolate, TEM-1, CTX-M-3, and AmpC in 1 isolate, but SHV was not detected. Antimicrobial resistance genes were transferred to animal isolate of E. coli (CCARM No. 1203) by the filter mating method. Extended spectrum $\beta-lactamase$ producers studied in the current study have low correlation to each other as determined by random amplified polymorphic DNA and pulsed field gel elec­trophoresis. This is a contradictory result from the general hypothesis that extended-spectrum $\beta-lactamase$ pro­ducers in one hospital is a result from a clonal spread.

• Restorative Dentistry and Endodontics
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• v.32 no.2
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• pp.102-110
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• 2007

The purpose of this study was to obtain the basic information for the improvement of dental environment by investigating the presence of methicillin- or vancomycin-resistant Staphylococcus aureus (MRSA or VRSA) isolated from dental health care workers (DHCWs) and environment of the Chosun University Dental Hospital (CUDH) and a private dental clinic (control group). Staphylococcus aureus (S. aureus) was isolated from anterior nares of 42 DHCWS and 38 sites, unit chairss, x-ray devices, computers, etc., at 10 departments of the CUDH and 20 DHCWs and 11 sites at the private dental clinic. S. aureus was isolated on mannitol salt agar plate and confirmed by PCR with S. aureus species-specific primer. Antimicrobial susceptibility test of clinical isolates of S. aureus against several antibiotics including methicillin (oxacillin) was performed by investigating minimum inhibitory concentration (MIC) using broth microdilution assay. In addition, PCR was performed to detect the methicillin- or vancomycin-resistant gene. The data showed that one strain of S. aureus was isolated from DHCWs of the CUDH and three strains of S. aureus was isolated from 3 samples of the private dental clinic, respectively. All of the isolates from the CUDH and the private dental clinic had resistance to penicillin G, amoxicillin and vancomycin and susceptibility to oxacillin and ciprofloxacin. The S. aureus strains were already obtained the resistance to penicillin G and amoxicillin. These results suggest that two dental clinics were under relatively safe environment.

• Journal of Life Science
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• v.25 no.4
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• pp.433-440
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• 2015

Several studies suggest that regular consumption of walnuts may have beneficial effects against oxidative stress-mediated disease such as cancer. The present study reports the total phenolic and flavonoid contents, together with the antioxidant and antibacterial activities of several solvent extracts (methanol, n-hexane, ethyl acetate, n-butanol, and water) obtained from walnut (Juglans regia L.) green husk. MIC (minimal inhibitory concentration) values of the walnut extracts for 8 human pathogenic bacteria strain were determined using agar dilution method. Antioxidant activity of extracts were assessed using DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)) assays, EC₅₀ of DPPH and ABTS scavenging activities, and determination of total phenolic and flavonoid content and its correlation with DPPH and ABTS scavenging capacities. Among the six extracts, ethyl acetate extract (EtOAc Ex) showed the highest antimicrobial activity at 3.2 mg/ml of MICs against Staphylococcus aureus SG511. Total flavonoids and polyphenol contents of EtOAc Ex were 42.48 mg of quercetin equivalents (QE)/g and 223.25 mg of gallic acid equivalents (GAE)/g respectively. The highest antioxidative potential was shown by the sample extracted with EtOAc Ex (EC₅₀=13.43 μg/ml for DPPH and EC₅₀=41.83 μg/ml for ABTS radical scavenging activity assay). These results showed that J. regia green husk extracts can be used as an easily accessible source of natural antibacterial agents and natural antioxidants.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.185-194
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• 2006

The aim of this study was to identify the bacteria isolated from endodontic lesions by cell culture and to determine the antimicrobial susceptibility of them against 8 antibiotics. The necrotic pulpal tissues were collected from 27 infected root canals, which were diagnosed as endodontic infection. Samples were collected aseptically from the infected pulpal tissue of the infected root canals using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing $500{\mu}l\;of\;1{\times}PBS$. The sample solution was briefly mixed and plated onto a BHI-agar plate containing 5% sheep blood. The agar plates were incubated in a $37^{\circ}C$ anaerobic chamber for 2 to 5 days. The bacteria grown on the agar plates were identified by comparison of 16S rRNA gene (rDNA) sequencing method at the species level. To test the sensitivity of the bacteria isolated from the infected root canals against 8 antibiotics, minimum inhibitory concentrations (MIC) were determined using broth dilution assay. The data showed that 101 bacterial strains were isolated and were identified. Streptococcus spp. (29.7%) and Actinomyces spp. (21.8%) were predominantly isolated. The 9 strains were excluded in antimicrobial susceptibility test because they were lost during the experiment or were not grown in broth culture. The percentage of bacteria susceptible for each antibiotic in this study was clindamycin, 87.0% (80 of 92); tetracycline, 75.0% (69 of 92); cefuroxime axetil, 75.0% (69 of 92); amoxicillin + clavulanic acid (5:1), 71.7% (66 of 92); penicillin G, 66.3% (61 of 92); erythromycin, 66.3% (61 of 92); amoxicillin, 44.6% (41 of 92); and ciprofloxacin, 31.5% (29 of 92). The susceptibility pattern of 8 antibiotics was dependent on the host of the bacteria strains rather than the kinds of bacterial species. These results indicate that antibiotic susceptibility test should be performed when antibiotics are needed for the treatment of infected root canals.

• The Korean Journal of Food And Nutrition
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• v.16 no.1
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• pp.7-14
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• 2003

This study mainly focused on to investigate the effects of Schizandra chinensis on the growth of a bacterium, CS6 which was isolated from kimchi. CS6 was final]y identified to lactobacillus plantarum that caused acidification of kimchi. The ethanolic extract of Schizandra chinensis(EES) inhibited the growth of L. plantarum. Minimum inhibition concentration of crude EES on L. plantarum was 62.5mg/$m\ell$. In broth culture, 5$\mu\textrm{g}$/$m\ell$ of EES completely inhibited the growth of L. plantarum during fermentation. The addition of 0.4% of EES has no apparent effect on quality including the taste and color on kimchi. It was expected that EES-containing kimchi could extend the period of preservation. Analysis of organic acids in water fractions of EES was carried out by HPLC. It is apparent that antimicrobial active fractions contained the highest concentration of succinic acid, a little tartaric acid and malic acid. Among these organic acids, succinic acid showed the strong inhibitory effect against L. plantarum CS6 in vitro. Succinic acid-containing kimchi with a concentration of 0.4 and 0.5% had the inhibitory effect on growth of L. plantarum. Inhibitory effect of EES on amylase, cellulase and pectinase was also tested. In conclusion, the present experiment demonstrated that EES inhibited the growth of L. plantarum, and various enzyme activity. EES-containing kimchi was sustained the hardness, and initial acidity during fermentation. EES was considered as the possible additive of kimchi process and EES added in kimchi increase the quality, and storage period of kimchi.

• Journal of Mushroom
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• v.22 no.2
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• pp.60-66
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• 2024

This study was conducted to selection and investigate appropriate conditions for mass production of antagonistic microbes to control cobweb disease caused by Cladobotryum mycophilum. A grampositive bacterium was isolated from spent substrate of Agaricus bisporus and showed significant antagonistic activity against Cladobotryum mycophilum. The bacterium was identified as Bacillus altitudinis. based on the cultural, biochemical and physiological characteristics, and 16S rRNA sequence. The isolate is saprophytic, but not parasitic nor pathogenic to cultivated mushroom whereas it showed strong inhibitory effects against C. mycophilum cells in vitro. The control efficacy of B. altitudinis HC7 against cobweb disease of C. mycophilum was up to 78.2% on Agaricus bisporus. The suppressive bacterium may be useful for the development of biocontrol system. To define the appropriate conditions for the mass production of the Bacillus altitudinis HC7, we have investigated appropriate culture conditions and effects of various nutrient source on the bacterial growth. The appropriate initial pH and temperature were determined as pH 6.0 and 30℃, respectively. The appropriate concentration of medium elements for the growth of pathogen inhibitor bacterium(Bacillus altitudinis HC7) was determined as follows: 3.0% soluble startch, 10% soytone, 1.0% (NH₄)₂HPO₄, 1.0 mmol KCl, and 0.5% L-asparagine.