• The Korean Journal of Nuclear Medicine
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• v.33 no.3
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• pp.306-315
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• 1999

Purpose: We performed this study to evaluate the process of radiation induced apoptosis in A431 skin epithelial cancer cell line. Materials and Methods: Low to high dose radiation (0, 2, 5, 10, 25 Gy) was given to A431 cells by Cs-137 cell irradiator. Apoptosis was evaluated by cell morphology, dye exclusion test, and DNA laddering. Results: Cell viability decreased as the radiation dose increased. Number of apoptotic bodies increased as radiation dose increased. It increased most significantly at 12 hours after irradiation. Lactate dehydrogenase activity in culture medium increased according to radiation dose and time after irradiation. DNA ladders could be identified in irradiated cells, but, it had no correlation with radiation dose or time after irradiation. Conclusion: Radiation-induced apoptosis which was the main course of cell death in A431 cells could be analyzed quantitatively by counting apoptotic bodies under microscope. Apoptosis increased as radiation dose increased.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.239-244
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• 1989

This work was for the elucidation of heterogeneity in a natural population of Rhizobium japonicum existing in Seoul National University's Experiment Field and of sensitivities of R. japonicum isolates for several antibiotics by using a method based on intrinsic antibiotic resistance (IAR). In addition, the suitability of IAR method for the recognition of R. japonicum strain was elucidated. Twenty seven isolates from various soybean cultivars cultivated at SNU's Experiment Field were tested to 4 antibiotics (streptomycin sulphate, kanamycin sulphate, ampicillin, oxytetracycline);There were 21 different IAR patterns among 27 isolates. It demonstrated diverse distribution of R. japonicum strains in SNU's Experiment Field. Their growth was inhibited at from a low concentration of about $1{\mu}g/ml$ to a high concentration of $400{\mu}g/ml$ for streptomycin sulphate, ampicillin, and oxytetracyclin. For kanamycin sulphate, on the contrary, all 27 isolates showed their growth inhibitances at below the concentration of $12.5{\mu}g/ml$. Two isolates identified as different strains from each other by the previous seroimmunological tests showed the same sensitivities for 4 antibiotics, and it seemed that IAR method was not perfect for the exact recognition of R. japonicum strain.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.167-174
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• 2012

Purpose: The respiration is one of the most important factors in respiratory gating radiation therapy (RGRT). We have developed an unique respiratory guidance system using an audio-visual system in order to support and stabilize individual patient's respiration and evaluated the usefulness of this system. Materials and Methods: Seven patients received the RGRT at our clinic from June 2011 to April 2012. After breathing exercise with the audio-visual system, we measured their spontaneous respiration and their respiration with the audio-visual system respectively. With the measured data, we yielded standard deviations by the superficial contents of respiratory cycles and functions, and analyzed them to examine changes in their breathing before and after the therapy. Results: The PTP (peak to peak) of the standard deviations of the free breathing, the audio guidance system, and the respiratory guidance system were 0.343, 0.148, and 0.078 respectively. The respiratory cycles were 0.645, 0.345, and 0.171 respectively and the superficial contents of the respiratory functions were 2.591, 1.008, and 0.877 respectively. The average values of the differences in the standard deviations among the whole patients at the CT room and therapy room were 0.425 for the PTP, 1.566 for the respiratory cycles, and 3.671 for the respiratory superficial contents. As for the standard deviations before and after the application of the PTP respiratory guidance system, that of the PTP was 0.265, that of the respiratory cycles was 0.474, and that of the respiratory superficial contents. The results of t-test of the values before and after free breathing and the audio-visual guidance system showed that the P-value of the PTP was 0.035, that of the cycles 0.009, and that of the respiratory superficial contents 0.010. Conclusion: The respiratory control could be one of the most important factors in the RGRT which determines the success or failure of a treatment. We were able to get more stable breathing with the audio-visual respiratory guidance system than free breathing or breathing with auditory guidance alone. In particular, the above system was excellent at the reproduction of respiratory cycles in care units. Such a system enables to reduce time due to unstable breathing and to perform more precise and detailed treatment.

• Journal of Food Hygiene and Safety
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• v.14 no.4
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• pp.319-326
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• 1999

Recently, it is continuously rising to concern about the health risk being induced by microorganisms in food such as Escherichia coli O157:H7 and Listeria monocytogenes. Various organizations and regulatory agencies including U.S.FPA, U.S.DA and FAO/WHO are preparing the methodology building to apply microbial quantitative risk assessment to risk-based food safety program. Microbial risks are primarily the result of single exposure and its health impacts are immediate and serious. Therefore, the methodology of risk assessment differs from that of chemical risk assessment. Microbial quantitative risk assessment consists of tow steps; hazard identification, exposure assessment, dose-response assessment and risk characterization. Hazard identification is accomplished by observing and defining the types of adverse health effects in humans associated with exposure to foodborne agents. Epidemiological evidence which links the various disease with the particular exposure route is an important component of this identification. Exposure assessment includes the quantification of microbial exposure regarding the dynamics of microbial growth in food processing, transport, packaging and specific time-temperature conditions at various points from animal production to consumption. Dose-response assessment is the process characterizing dose-response correlation between microbial exposure and disease incidence. Unlike chemical carcinogens, the dose-response assessment for microbial pathogens has not focused on animal models for extrapolation to humans. Risk characterization links the exposure assessment and dose-response assessment and involve uncertainty analysis. The methodology of microbial dose-response assessment is classified as nonthreshold and thresh-old approach. The nonthreshold model have assumption that one organism is capable of producing an infection if it arrives at an appropriate site and organism have independence. Recently, the Exponential, Beta-poission, Gompertz, and Gamma-weibull models are using as nonthreshold model. The Log-normal and Log-logistic models are using as threshold model. The threshold has the assumption that a toxicant is produce by interaction of organisms. In this study, it was reviewed detailed process including risk value using model parameter and microbial exposure dose. Also this study suggested model application methodology in field of exposure assessment using assumed food microbial data(NaCl, water activity, temperature, pH, etc.) and the commercially used Food MicroModel. We recognized that human volunteer data to the healthy man are preferred rather than epidemiological data fur obtaining exact dose-response data. But, the foreign agencies are studying the characterization of correlation between human and animal. For the comparison of differences to the population sensitivity: it must be executed domestic study such as the establishment of dose-response data to the Korean volunteer by each microbial and microbial exposure assessment in food.

• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.79-87
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• 2010

Research was initiated to investigate the early establishment characteristics and germination patterns of perennial ryegrass (PR, Lolium perenne L.). Eight cultivars of PR were evaluated in the study. Experiment was conducted under a room temperature condition of $6^{\circ}C$ to $23^{\circ}C$ (natural conditions). Daily and cumulative germination patterns were measured and analyzed on a daily basis. Significant differences were observed in germination pattern, days to the first germination, days to 50% germination, days to 75% germination, and germination percentage with different environments and cultivars. Germination percentage was variable with cultivars at the end of study. It was 66.25 to 93.50% under natural conditions. There were considerable variations in the early germination characteristics and germination pattern among the entries according to different conditions. The first germination was initiated between 3 and 5 DAS (days after seeding) under ISTA (International Seed Testing Association) conditions. But it started between 6 and 8 DAS under natural conditions, being 2 to 4 days later as compared with that under ISTA conditions. It was 8 to 12 DAS that reached to days to the 50% germination, which was 2 to 5 days after the first germination. Days to the 75% germination were 10.08 to 13.70 DAS under natural conditions, being 2.07 to 5.70 days slower as compared with ISTA conditions. 'Pennant II' was the fastest cultivar. But the slowest was 'Catalina II' that was 3.62 days later than 'Pennant II' under natural conditions. Considering days to the first germination, days to 75% germination, and germination pattern etc, 'Pennant II' and 'Brightstar II' were regarded as excellent cultivars under both conditions. From this study, information on differences in germination characteristics and patterns would be usefully applied for golf course design and construction, when established with PR.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.158-164
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• 2006

Offensive odor from CAFO(concentrated animal feeding operation) and its control have become a significant issue in Korea. Control of odors from the CAFO requires to identify major odorant and their generation mechanisms. In this study, an easy method to collect gas sample and to quantify its odorants is proposed. The method involves on-site odorant extraction with solid-phase microextraction and quantitation with GC/MSD or GC/FID. Analytes of the current study include: trimethylamine(TMA), carbon disulfide($CS_2$), dimethyl sulfide(DMS), dimethyl disulfide(DMDS), acetic acid(AA), propionic acid(PA) and n-butyric acid(BA). The resulting linearity($R^2$) of calibration curve for each analyte was good over the range from several ppbv to ppmv; 0.984 for TMA(0.056-1.437), 0.996 for $CS_2$(0.039-0.999), 0.994 for DMS(0.029-0.756), 0.995 for DMDS(0.024-0.623), 0.992 for AA(0.068-1.314), 0.955 for PA(0.047-0.940), and 0.976 for BA(0.036-0.712). Method detection limits were 5.67, 6.39, 5.78, 25.2, 0.098, 0.363 and 0.099 ppbv for AA, PA, BA, TMA, DMS, $CS_2$, and DMDS, respectively. With the developed method, odorants from poultry, swine, and cattle barns were analysed. All the compounds but DMDS were detected from the sample collected in the poultry barn, and their levels exceeded the representative published human olfactory threshold.

• Clinical and Experimental Pediatrics
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• v.45 no.2
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• pp.214-222
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• 2002

Purpose : The aim of this study was to evaluate myocardial injury in children treated with adriamycin by echocardiography, which is non-invasive and safe measurement for children. Methods : Left ventricular dimensions, wall stress, and contractile function were determined by echocardiographic methods in 17 patient recepients with adriamycin chemotherapy at rest(group 1) and during stress(group 2). Twenty age-matched normal subjects were established as control group. Results : End-diastolic dimension was decreased in both groups(group 1; $92{\pm}7%$ of normal, group 2; $87{\pm}8%$ of normal, P<0.05). Left ventricular end diastolic volume and wall mass were also decreased in both groups(group 1; $96{\pm}12mL/m^2$ and $145{\pm}18g/m^2$, group 2; $87{\pm}8mL/m^2$ and $137{\pm}16g/m^2$, respectively, P<0.05 and P<0.05) and group 2 showed lower values than group 1. Meridional end systolic stress(ESSm) was increased in both groups but there was no significant difference between the two groups(group 1; $52.6{\pm}6.2g/cm^2$, group 2; $63.5{\pm}8.5g/cm^2$, P<0.05, normal value $45.7{\pm}3.5g/cm^2$). The load-independent relation of rate-corrected circumferential fiber shortening velocity(Vcfc) to ESSm has a significant abnormal change in 7 out of 17(41%) in group 1 and 12 out of 17(71%) in group 2. Conclusion : The load-dependent systolic index, such as fractional shortening, may fail to show abnormality because of the compensatory changes in preload and afterload which can mask the impaired contractility. Therefore, systolic performance also should be monitored by a load-indepedent contractility index such as slope value of the end-systolic pressure-dimension relation and the position of the left ventricular stress-fiber shortening velocity after exercise.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.2 no.2
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• pp.68-73
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• 2009

Purpose: We retrospectively studied the outcomes of the shoulder impingement syndrome for the treatment of the ultrasound-guided subacromial bursal steroid injection. Materials and Methods: Sixty-six shoulders of sixty-two patients with shoulder impingement syndrome treated from March, 2006 to April, 2009 were involved in this study. All cases underwent standardized, nonoperative treatment protocol consisting of 5~12 MHz high resolution ultrasound-guided local steroid injection into the subacromial bursa in modified Crass position. The shoulder range of motion, VAS score and impingement signs were evaluated during the initial and 1year visits. After injection, shoulder elevation exercise was encouraged. Statistical analysis with ANOVA model and Tukey's post-hoc test with the significance level at 5% were performed using SAS program. Results: All cases showed improved range of motion without limitation of shoulder function at immediate post-injection, 6-week, 3-month and 1year visits. The average VAS score at one year follow-up decreased to 2.85 from 6.47 before injection. In all cases the impingement signs became negative immediate after injection. However, 6 cases showed positive impingement signs after 6-week, which became negative after reinjection. The range of motion and VAS score were improved at one-year follow-up compared to initial visit (p<0.0001). No complication was noted at all follow-up period. Conclusion: Ultrasound-guided subacromial steroid injection alleviated the need of surgery, because it was successful in all our cases to improve pain and function of the shoulders until one year follow-up period.

• Investigative Magnetic Resonance Imaging
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• v.18 no.2
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• pp.120-132
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• 2014

Purpose : To compare dynamic susceptibility contrast imaging, diffusion-weighted imaging, and susceptibility-weighted imaging (SWI) for the differentiation of tumor recurrence and delayed radiation therapy (RT)-related changes in patients treated with RT for primary brain tumors. Materials and Methods: We enrolled 24 patients treated with RT for various primary brain tumors, who showed newly appearing enhancing lesions more than one year after completion of RT on follow-up MRI. The enhancing-lesions were confirmed as recurrences (n=14) or RT-changes (n=10). We calculated the mean values of normalized cerebral blood volume (nCBV), apparent diffusion coefficient (ADC), and proportion of dark signal intensity on SWI (proSWI) for the enhancing-lesions. All the values between the two groups were compared using t-test. A multivariable logistic regression model was used to determine the best predictor of differential diagnosis. The cutoff value of the best predictor obtained from receiver-operating characteristic curve analysis was applied to calculate the sensitivity, specificity, and accuracy for the diagnosis. Results: The mean nCBV value was significantly higher in the recurrence group than in the RT-change group (P=.004), and the mean proSWI was significantly lower in the recurrence group (P<.001). However, no significant difference was observed in the mean ADC values between the two groups. A multivariable logistic regression analysis showed that proSWI was the only independent variable for the differentiation; the sensitivity, specificity, and accuracy were 78.6% (11 of 14), 100% (10 of 10), and 87.5% (21 of 24), respectively. Conclusion: The proSWI was the most promising parameter for the differentiation of newly developed enhancing-lesions more than one year after RT completion in brain tumor patients.

• Journal of dental hygiene science
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• v.8 no.1
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• pp.13-20
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• 2008

The purpose of this study was to find out experiences of dental hygienists working on dental care sites, to prevent potential malpractice accidents and disputes, and to examine why it is necessary to provide corresponding education or training courses. As a result, this study came to the following conclusions: 1. It was found that 32.5% had ever experienced in malpractice suits or disputes, and 55.0% of such experienced group had ever experienced in malpractice suits or disputes concerned with dental hygienists. 2. According to inquiry on whether dental hygienists have certain liability for malpractice disputes, it was found that 66.3% respondents ascribed the medical liability to dental hygienists. And according to inquiry for those respondents on liability ratio, it was found that 57.1% of them thought 11%~30% as appropriate liability ratio. 3. According to survey on extent of doubts about potential malpractice accidents and disputes in future, it was found that 72.4% respondents sometimes had doubts about them. 4. It was found that 64.2% respondents thought it necessary and urgent to provide education related to prevention and countermeasures for malpractice disputes.