1.Increased Catalase Activity by All-trans Retinoic Acid and Its Effect on Radiosensitivity in Rat Glioma Cells.
Hua JIN ; Ha Yeun JEON ; Woo Yoon PARK ; Won Dong KIM ; Hee Yul AHN ; Jae Ran YU
The Journal of the Korean Society for Therapeutic Radiology and Oncology 2005;23(4):211-216
PURPOSE: It has been reported that all-trans retinoic acid (ATRA) can inhibit glioma growing in vitro. However, clinical trials with ATRA alone in gliomas revealed modest results. ATRA has been shown to increase radiosensitivity in other tumor types, so combining radiation and ATRA would be one of alternatives to increase therapeutic efficacy in malignant gliomas. Thus, we intended to know the role of catalase, which is induced by ATRA, for radiosensitivity. If radiation-reduced reactive oxygen species (ROS) is removed by catalase, the effect of radiation will be reduced. MATERIALS AND METHODS: A rat glioma cell line (36B10) was used for this study. The change of catalase activity and radiosensitivity by ATRA, with or without 3-amino-1, 2, 4-triazole (ATZ), a chemical inhibitor of catalase were measured. Catalase activity was measured by the decomposition of H2O2 spectrophotometrically. Radiosensitivity was measured with clonogenic assay. Also ROS was measured using a 2, 7-dichlorofluorescein diacetate spectrophotometrically. RESULTS: When 36B10 cells were exposed to 10, 25 and 50microM of ATRA for 48 h, the expression of catalase activity were increased with increasing concentration and incubation time of ATRA. Catalase activity was decreased with increasing the concentration of AT (1, 10 mM) dose-dependently. ROS was increased with ATRA and it was augmented with the combination of ATRA and radiation. ATZ decreased ROS production and increased cell survival in combination of ATRA and radiation despite the reduction of catalase. CONCLUSION: The increase of ROS is one of the reasons for the increased radiosensitivity in combination with ATRA. The catalase that is induced by ATRA doesn`t decrease ROS production and radiosensitivity.
Animals
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Catalase*
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Cell Line
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Cell Survival
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Glioma*
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Radiation Tolerance*
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Rats*
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Reactive Oxygen Species
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Tretinoin*
2.Korean Nationwide Surveillance of Antimicrobial Resistance of bacteria in 1997.
Yunsop CHONG ; Kyungwon LEE ; Yeon Joon PARK ; Dong Seok JEON ; Myung Hee LEE ; Moon Yeun KIM ; Chul Hun CHANG ; Eui Chong KIM ; Nam Yong LEE ; Hyon Suk KIM ; Eun Suk KANG ; Hyun Chan CHO ; In Ki PAIK ; Hye Soo LEE ; Sook Jin JANG ; Ae Ja PARK ; Young Joo CHA ; Sung Ha KANG ; Myung Hee LEE ; Wonkeun SONG ; Jong Hee SHIN
Yonsei Medical Journal 1998;39(6):569-577
Antimicrobial-resistant bacteria are known to be prevalent in tertiary-care hospitals in Korea. Twenty hospitals participated to this surveillance to determine the nationwide prevalence of resistance bacteria in 1997. Seven per cent and 26% of Escherichia coli and Klebsiella pneumoniae were resistant to 3rd-generation cephalosporin. Increased resistance rates, 19% of Acinetobacter baumannii to ampicillin/sulbactam, and 17% of Pseudomonas aeruginoa to imipenem, were noted. The resistance rate to fluoroquinolone rose to 24% in E. coli, 56% in A. baumannii and 42% in P. aeruginosa. Mean resistance rates were similar in all hospital groups: about 17% of P. aeruginosa to imipenem, 50% of Haemophilus influenzae to ampicillin, 70% of Staphylococcus aureus to methicillin, and 70% of pneumococci to penicillin. In conclusion, nosocomial pathogens and problem resistant organisms are prevalent in smaller hospitals too, indicating nosocomial spread is a significant cause of the increasing prevalence of resistant bacteria in Korea.
Bacterial Physiology*
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Drug Resistance, Microbial*
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Hospitals
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Human
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Korea
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Microbial Sensitivity Tests
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Prevalence