• The Korean Journal of Pesticide Science
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• v.8 no.4
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• pp.309-318
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• 2004

Acute toxicity test and chronic toxicity test were conducted with killifish (Oryzias latipes, Medaka) to evaluate toxicity effect of pesticides. Acute toxicity test was investigated mortality in 48 hours and 96 hours after treatment, chronic toxicity test was examined with the early life stage of 30 days after hatching be started embryos of Medaka. The test substances were two pesticides, Carbosulfan and Phenthoate, applied to the paddy rice plant and well-known to the high fish toxicity. As the result of acute toxicity test, median concentration $(LC_{50})$ at 96 hours in Medata was Carbosulfan 0.102 mg/L and Phenthoate 0.167 mg/L, and Fish early life stage toxicity test was conducted on basis of the result of acute toxicity test and concluded from the investigation of hatching success, period of hatching, survival post hatching, length and weight of surviving fishes and abnormal fish. The results of early life stage toxicity test were represented by no observed effect concentration (NOEC), lowest observed effect concentration (LOEC) and maximum acceptable toxicant concentration (MATC). NOEC was Carbosulfan 0.0067ppm and Phenthoate 0.011ppm, LOEC of PCP-Na, Carbosulfan and Phenthoate were 0.017ppm and 0.029ppm, MATC of Carbosulfan and Phenthoate were 0.011ppm and 0.018ppm. These studies will be expected to supply more varied chronic toxicity effects at lower concentration than acute toxicity test. Therefore, evaluation data will be more realistic and the risk assessment of pesticide will be leveled up.

• The Korean Journal of Pesticide Science
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• v.16 no.2
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• pp.109-120
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• 2012

This study was conducted to monitor 284 pesticides residue level in 2,914 commercial agricultural products in the northern area of Seoul in 2011 by the multi class pesticide multiresidue analysis methods in Korea Food Code using GC, HPLC, GC-MSD and, LC-MSD. The detection rate of pesticide residues were 14.8% (431/2,914). The order of agricultural products in which the pesticide residues were detected was perilla leaves 40.0% (28/70), chamnamul 35.5% (11/31), amaranth 30.0% (3/10) and spinach 27.7% (38/137) etc. The percentage of products that exceeded the MRLs (maximum residue limits) were 1.0% (31/431). Those products that exceeded MRLs were ginseng (6), perilla leaves (4), leek (4), welsh onion (3) and sedeum (3) etc. The 59 kinds of the pesticides were detected on this study, 21 pesticides of them were detected over MRLs. Detection rate of fungicides (56.4%) was higher than that of insecticides (42.1%). And procymidone was detected with considerable high frequency. Additionally, residual residual violates pesticides were in the order of tolclofos-methyl, endosulfan, dimethomorph, diniconazole and fludioxonil. According to the agricultural marketing channels, detection and excess rate of them were monitored. Detection and excess rate of samples circulated in agricultural traditional market were highest. The estimated daily intakes (EDI) of the pesticides were compared to personal acceptable daily intakes (PADI) in order to risk assessment by food consumption. Diazinon in Korean cabbage showed the highest %ADI, 2.9901 and others showed below 3.0 %ADI. Overall, these results indicate that residue levels of pesticides detected were evaluated as safe.

• The Korean Journal of Pesticide Science
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• v.14 no.1
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• pp.10-15
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• 2010

Most pesticides are poorly soluble in water and must be dissolved in a solvent carrier before being added to the test medium on aquatic toxicity test. The concentration of solvent is critical to the success of a test. This study were conducted to recommend possible organic solvents which have good solubility for pesticides and low toxicity to Korean native water flea to establish new standard toxicity test methods using Korean native water flea for ecological risk assessment of pesticide. Four Korean freshwater cladocerans, Daphnia obtusa, Daphnia sp., Moina macrocopa and Simocephalus vetulus were exposed to 10 different organic solvents during 48 hours to evaluate their toxic response to solvents. Ethyl acetate was the most toxic to cladocerans tested. Although ethyl ether was the least toxic to cladocerans tested, it may not adequate as possible solvent in aquatic toxicity test due to high volatility and low water solubility. In conclusion, acetone, methanol, ethanol and acetonitrile which has low toxicity as well as good water solubility are recommended as optimal organic solvent to use in aquatic toxicity tests with Korean native cladocerans tested.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.44-63
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• 2000

Situated close to Heathrow Airport, and adjacent to the M4 and M25 Motorways, the site at Axis Park is considered a prime location for business in the UK. In consequnce two of the UK's major property development companies, MEPC and Redrew Homes sought the expertise of Intergeo to remediate the contaminated former industrial site prior to its development. Industrial use of the twenty-six hectare site, started in 1936, when Hawker Aircraft commence aircraft manufacture. In 1963 the Firestone Tyre and Rubber Company purchased part of the site. Ford commenced vehicle production at the site in the mid-1970's and production was continued by Iveco Ford from 1986 to the plant's decommissioning in 1997. Geologically the site is underlain by sand and gravel, deposited in prehistory by the River Thames, with London Clay at around 6m depth. The level of groundwater fluctuates seasonally at around 2.5m depth, moving slowly southwest towards local streams and watercourses. A phased investigation of the site was undertaken, which culminated in the extensive site investigation undertaken by Intergeo in 1998. In total 50 boreholes, 90 probeholes and 60 trial pits were used to investigate the site and around 4000 solid and 1300 liquid samples were tested in the laboratory for chemical substances. The investigations identified total petroleum hydrocarbons in the soil up to 25, 000mg/kg. Diesel oil, with some lubricating oil were the main components. Volatile organic compounds were identified in the groundwater in excess of 10mg/l. Specific substances included trichloromethane, trichloromethane and tetrachloroethene. Both the oil and volatile compounds were widely spread across the site, The specific substances identified could be traced back to industrial processes used at one or other dates in the sites history Slightly elevated levels of toxic metals and polycyclic aromatic hydrocarbons were also identified locally. Prior to remediation of the site and throughout its progress, extensive liaison with the regulatory authorities and the client's professional representatives was required. In addition to meetings, numerous technical documents detailing methods and health and safety issues were required in order to comply with UK environmental and safety legislation. After initially considering a range of options to undertake remediation, the following three main techniques were selected: ex-situ bioremediation of hydrocarbon contaminated soils, skimming of free floating hydrocarbon product from the water surface at wells and excavations and air stripping of volatile organic compounds from groundwater recovered from wells. The achievements were as follows: 1) 350, 000m3 of soil was excavated and 112, 000m3 of sand and gravel was processed to remove gravel and cobble sized particles; 2) 53, 000m3 of hydrocarbon contaminated soil was bioremediated in windrows ; 3) 7000m3 of groundwater was processed by skimming to remove free floating Product; 4) 196, 000m3 of groundwater was Processed by air stripping to remove volatile organic compounds. Only 1000m3 of soil left the site for disposal in licensed waste facilities Given the costs of disposal in the UK, the selected methods represented a considerable cost saving to the Clients. All other soil was engineered back into the ground to a precise geotechnical specification. The following objective levels were achieved across the site 1) By a Risk Based Corrective Action (RBCA) methodology it was demonstrated that soil with less that 1000mg/kg total petroleum hydrocarbons did not pose a hazard to health or water resources and therefore, could remain insitu; 2) Soils destined for the residential areas of the site were remediated to 250mg/kg total petroleum hydrocarbons; in the industrial areas 500mg/kg was proven acceptable. 3) Hydrocarbons in groundwater were remediated to below the Dutch Intervegtion Level of 0.6mg/1; 4) Volatile organic compounds/BTEX group substances were reduced to below the Dutch Intervention Levels; 5) Polycyclic aromatic hydrocarbons and metals were below Inter-departmental Committee for the Redevelopment of Contaminated Land guideline levels for intended enduse. In order to verify the qualify of the work 1500 chemical test results were submitted for the purpose of validation. Quality assurance checks were undertaken by independent consultants and at an independent laboratory selected by Intergeo. Long term monitoring of water quality was undertaken for a period of one year after remediation work had been completed. Both the regulatory authorities and Clients representatives endorsed the quality of remediation now completed at the site. Subsequent to completion of the remediation work Redrew Homes constructed a prestige housing development. The properties at "Belvedere Place" retailed at premium prices. On the MEPC site the Post Office, amongst others, has located a major sorting office for the London area. Exceptionally high standards of remediation, control and documentation were a requirement for the work undertaken here.aken here.

• Radiation Oncology Journal
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• v.18 no.1
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• pp.40-45
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• 2000

Purpose : To evaluate the histopathological prognostic factors, relapse pattern and survival in patients with endometrial carcinoma who were treated with surgery and postoperative adjuvant radiotherapy (RT). Methods and Materials : From September 1991 to December 1997, 27 patients with endometrial carcinoma treated with surgery and postoperative adjuvant RT at Asan Medical Center were entered in this study. Surgery was peformed with total abdominal hysterectomy in six, total abdominal hysterectomy with pelvic lymph node dissection in eight and radical hysterectomy in 13 patients. External RT of 50.4 Gy was done to all patients and among these, additional high dose rate vaginal vault irradiation of 20$\~$25 Gy with fractional dose of 4$\~$5 Gy was boosted In 16 patients. The patients were followed for 6$\~$95 months(median 30). Results : The number of patients according to FIGO stage were I 18 (67$\%$), II 1 ($4\%$) and III 7 ($26\%$). Patients with poor histologic grade, deep myometrial invasion, adnexal involvement, lymphovascular invasion showed more pelvic lymph node involvement, but no statistical significance was indicated. The 5 year overall and disease free survival were 100$\%$ and 76.8$\%$, respectively. Relapse sites were pelvic, para-aortic lymph node, and multiple metastases including lung, and no vaginal relapse was developed. Factors that were associated with disease free survival were FIGO stage (p=0.01), lymphovascular invasion (p=0.03), pelvic lymph node involvement (p=0.0001). There was only one Grade 1 rectal bleeding without moderate to severe complications. Conclusion : Postoperative adjuvant RT is considered to reduce the loco-regional failure, resulting the improvement of survival. The group of patients with the risk of vaginal failure without vaginal vault irradiation should be investigated according to stage and grade.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.201-205
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• 2007

Purpose: This retrospective study was conducted to assess outcome and to determine the prognostic factors in patients with a desmoid tumor treated with postoperative radiotherapy. Materials and Methods: Twenty-seven patients with a desmoid tumor who were treated with postoperative radiotherapy between June 1984 and October 2005 were analyzed. There were 13 male and 14 female patients. The age of the patients ranged from 3 to 79 years (median age, 28 years). Tumors were located in an extra-abdominal area (21 cases), and in the abdominal walls (6 cases). The tumor size ranged from 2.5 to 25 cm (median size, 7.5 cm) in the largest linear dimension. Thirteen cases received radiotherapy after initial surgery, and 14 recurrent cases received radiotherapy after additional surgery. The total radiation dose given was $45{\sim}66$ Gy (median dose, 59.4 Gy), and the fraction size was $1.8{\sim}2.0$ Gy. Results: The median follow-up period was 61 months (range, $12{\sim}203$ months). Two patients developed local progression and six patients experienced local recurrence. The 5-year disease-free survival rate and the 5-year progression-free survival rate were 61 % and 70%, respectively. Wide local excision was associated with better disease free survival with statistical significance (p=0.028). Radiotherapy after initial surgery (p=0.046) and a higher radiation dose of more than 60 Gy (p=0.049) were associated with better progression free survival with statistical significance. At the time of the last follow-up, the number of additional surgeries was higher in patients that received radiotherapy after reoperation (p<0.001). Conclusion: Radiotherapy after the initial operation improved local control and decreased the number of subsequent operations. Thus, postoperative radiotherapy after an initial operation is recommended in patients with a high risk of recurrence for a desmoid tumor.

• Childhood Kidney Diseases
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• v.11 no.2
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• pp.229-238
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• 2007

Purpose : Since the first febrile UTI(urinary tract infection) in infants is commonly associated with vesicoureteral reflux(VUR), imaging studies such as renal ultrasonography, dimercaptosuccinic acid(DMSA) scan, and voiding cystourethrography(VCUG) are recommended. How-ever, because of the invasiveness of VCUG, it is difficult to perform in all young infants with febrile UTI. The purpose of this study is to compare the clinical and laboratory characteristics, radiologic findings between the young infant group(1 to 6month, n=121) and the old infant group(7 to 24months, n=91), and to determine the clinical and radiologic risk factors that predict the presence of VUR before the VCUG in patients with their first febrile UTI under 2 years of age. Methods : We reviewed the medical records of 211 first febrile UTI patients under 2 years of age retrospectively, and compared clinical, laboratory, and radiologic findings between the two age groups. Results : The young infant group had a male preponderance and a higher incidence of Escherichia coli in their urine culture. The incidence of acute renal parenchymal defects on DMSA scans were significantly increased in the young infant group. The incidence of VUR was 29% in patients who had a VCUG, but there were no differences in the incidence of VUR between the two age groups. Abnormal findings on DMSA scan significantly correlated with higher incidence of VUR in the young infant group. Incidence of abnormal findings DMSA scan significantly increased with high grade VUR(garde III-V ). Conclusion : In treating first febrile UTI patients under 2 years, physicians have to consider such characteristics as age less than 6 months, male preponderance, E.coli in the urine culture, and increased incidence of abnormal findings on DMSA scans which correlated well with the presence of VUR. The results of the DMSA scan might help us to predict the presence of VUR before the VCUG in first febrile UTI and help us to reduce performing invasive radio-logic studies especially in the young infant group. (J Korean Soc Pediatr Nephrol 2007;11:229-238)

• Journal of the Korean Society of Radiology
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• v.11 no.1
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• pp.9-17
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• 2017

A high degree of precision and accuracy in Gamma Knife Radiosurgery(GKRS) is a fundamental requirement for therapeutical success. Elaborate radiation delivery and dose gradients with the steep fall-off of radiation are clinically applied thus necessitating a dedicated Quality Assurance(QA) program in order to guarantee dosimetric and geometric accuracy and reduce all the risk factors that can occur in GKRS. In this study, as a part of QA we verified the accuracy of single-shot dose profiles used in the algorithm of Gamma Knife Perfexion(PFX) treatment planning system employing Variable Ellipsoid Modeling Technique(VEMT). We evaluated the dose distributions of single-shots in a spherical ABC phantom with diameter 160 mm on Gamma Knife PFX. The single-shots were directed to the center of ABC phantom. Collimating configurations of 4, 8, and 16 mm sizes along x, y, and z axes were studied. Gamma Knife PFX treatment planning system being used in GKRS is called Leksell GammaPlan(LGP) ver 10.1.1. From the verification like this, the accuracy of GKRS will be doubled. Then the clinical application must be finally performed based on precision and accuracy of GKRS. Specifically the width at the 50% isodose level, that is, Full-Width-of-Half-Maximum(FWHM) was verified under such conditions that a patient's head is simulated as a sphere with diameter 160mm. All the data about dose profiles along x, y, and z axes predicted through VEMT were excellently consistent with dose profiles from LGP within specifications(${\leq}1mm$ at 50% isodose level) except for a little difference of FWHM and PENUMBRA(isodose level: 20%~80%) along z axis for 4 mm and 8mm collimating configurations. The maximum discrepancy of FWHM was less than 2.3% at all collimating configurations. The maximum discrepancy of PENUMBRA was given for the 8 mm collimator along z axis. The difference of FWHM and PENUMBRA in the dose distributions obtained with VEMT and LGP is too small to give the clinical significance in GKRS. The results of this study are considered as a reference for medical physicists involved in GKRS in the whole world. Therefore we can work to confirm the validity of dose distributions for all collimating configurations determined through the regular preventative maintenance program using the independent verification method VEMT for the results of LGP and clinically assure the perfect treatment for patients of GKRS. Thus the use of VEMT is expected that it will be a part of QA that can verify and operate the system safely.

• Journal of Chest Surgery
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• v.36 no.4
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• pp.261-266
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• 2003

Background: Surgery of abdominal aortic aneurysm revealed high operative mortality. We reviewed our 11-years' experiences of abdominal aortic aneurysm operation and wish to obtain information on the treatment. Material and Method: From Jan. 1990 to Dec. 2000, 48 patients were operated due to abdominal aortic aneurysm in Yonsei Cardiovascular Center Mean age was $62.8{\pm}12.7$ and there were 40 males and 8 females. Among 48 patients, nine patients had ruptured abdominal aortic aneurysm, and mean aneurysm diameter of non-ruptured cases was $8.8{\pm}2.4$cm. Result: There were 6 early deaths, and early mortality was 12.5%. Among 9 patients of preoperative aneurysm rupture, three patients died (33.3%), and among 39 patients of non-ruptured cases, 3 patients died (7.7%). Among preoperative variables, age (p<0.05), preoperative BUN level (p<0.05), and DM (p<0.05) were risk factors of early mortality. Among discharged 42 patients, 40 patients were followed up (f/u rate=95.2%) and mean follow up was $3.6{\pm}0.2$ years. During follow up periods, five patients died (late mortality=11.9%), and Kaplan-Meier survival analysis revealed $81.7{\pm}7.6$% survival rate at five and ten year. Linealized incidence of graft related event was 3.53% per patient-year. Conclusion: Surgical mortality of ruptured abdominal aortic aneurysm was higher than non-ruptured cases; therefore, early resection of the aneurysm can decrease the surgical mortality.

• Pediatric Infection and Vaccine
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• v.16 no.2
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• pp.150-161
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• 2009

Purpose : Staphylococcus aureus causes a variety of infections, ranging from benign skin infections to fatal invasive infections. Recently, methicillin-resistant S. aureus (MRSA) infections have emerged in patients who do not have established risk factors. This study was conducted to characterize S. aureus infections in children with an emphasis on communityassociated MRSA infections at a tertiary care pediatric facility during a 3-year period. Methods : Four hundred twenty-nine cases of S. aureus infections diagnosed at the Seoul National University Children's Hospital between January 2004 and December 2006 were retrospectively reviewed. The cases were classified as hospitalonset (HO) or community-onset (CO), healthcare-associated (HA), or community-associated (CA) infections. Results : Among the 206 cases <1 year of age, 72%, 7%, and 21% were HO-HA, CO-HA, and CA infections, respectively, as compared to 48%, 28%, and 24% among the 223 cases >1 year of age. The proportion of CO-HA infections among HA infections (8.6% vs. 37.1%, P<0.001) and the proportion of HA infections among the CO infections (24.5% vs. 54.3%, P <0.001) were greater in older children than in infants. Overall, 57% of the isolates were methicillin-resistant. Twenty-nine (30%) of 96 CA strains were MRSA, and the most common site of CA-MRSA infection was the skin and soft tissues (26 cases). Conclusion : The methicillin resistance rate of S. aureus from CA infections was high and CA-MRSA was most often associated with skin and soft tissue infections.