• Clinical and Experimental Pediatrics
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• v.45 no.12
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• pp.1559-1570
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• 2002

Purpose : There has been no exact answer to the question of when to discontinue antiepileptic drugs(AEDs) in children with well-controlled epilepsy for a long period. This study is about the risk factors of relapse after withdrawal of AEDs in seizure(Sz)-free patients to show a guideline for discontinuation of AEDs. Methods : One hundred and sixty-nine children were diagnosed as epileptic at the Pediatric Dept. of Kyung-Hee Univ. between 1993 to 1998, in whom AEDs had been withdrawn after at least two years of Sz-free period. Univariate analysis using Kaplan-Meier survival analysis and multivariate analysis using Cox-proportional hazard model were performed for sixteen risk factors. Results : Forty-nine of the 169 patients(28.9%) had recurrence of Szs. The mean follow-up after withdrawal of AEDs was 4.1 years, mean treatment period was 4.1 years, and the mean Sz-free period was 3.3 years. Factors associated with an increased risk of relapse were young age at onset, symptomatic Sz, Sz type in West and Lennox-Gastaut syndrome, neurologic deficit, longer Sz-controlling period, shorter total treatment period, number of AEDs used(more than one drug), age at withdrawal of AEDs, and Sz-free period less than two years in univariate analysis using Kaplan-Meier mothod. From multivariate analysis, the factors indicating a significantly higher relapse risk were pre-treatment period after first Sz attack, Sz-controlling period, Sz-free period, number of AEDs used, neurologic abnormalities. Conclusion : For epileptic children who were Sz-free for more than two years, and were more than six-years-old, the discontinuation of AEDs should be considered positively, according to age of onset, Sz type, age at withdrawal of AEDs, total treatment period, Sz-controlling period, number of AEDs used, etiology, neurologic deficit, and the wishes of the patients and the their parents.

• Clinical and Experimental Pediatrics
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• v.46 no.10
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• pp.972-976
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• 2003

Purpose : For the control of childhood leukemia, of which the mortality is still high, the basic data for the incidence has a great importance. The authors analyzed the data from 133 new patients with childhood leukemia between 1996-2000 in Busan, Korea. Methods : The data were obtained from 133 new cases(87 males and 46 females from 0 to 15 years old) of childhood leukemia who were residents of Busan and who were admitted to the 4 university hospitals and 11 general hospitals from 1996 to 2000. Results : The total number of the new childhood leukemia patients was 133 between 1996-2000; the average annual number of new patients was 26.6. The age-and-sex adjusted annual incidence rate (/100,000) was in the range of 2.37-4.53(male 2.47-5.29, female 0.76-3.36) with an average of 3.29 (male 4.05, female 2.43). Age-specific annual incidence rate(/100,000) was 3.78 in the 0-4 year age group, 3.51 in the 5-9 year age group and 3.08 in the 10-14 year age group. Of the major types of childhood leukemia, the distribution of ALL was average 71.4%, of AML 23.3%, and of CML 4.5%. Of the major types of leukemia by age range, ALL showed highest in the 5-9 year age group, while AML in 0-4 and 10-14 year age groups. Sex-ratio(male to female) of major type of leukemia was 1.97 : 1 and 1.21 : 1, in ALL and AML groups, respectively, while all were male in CML. Conclusion : The average age-and-sex adjusted annual incidence rate(/100,000) of childhood leukemia in Busan from 1996 to 2000 was 3.29. Compared to data in related articles, this data suggests a steady increase in the incidence of childhood leukemia in the Busan area over the last 20 years since 1981.

• Clinical and Experimental Pediatrics
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• v.50 no.10
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• pp.1005-1010
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• 2007

Purpose : To determine the optimal time of high dose intravenous immune globulin (IVIG) treatment, we analysed the clinical characteristics and progress of a group of Kawasaki disease patients who had early treatment with IVIG. Method : A retrospective study was conducted of 188 patients with Kawasaki disease who were admitted to Yeungnam University Medical Center from January 2000 to December 2005. All patients were treated with a high dose IVIG and high dose aspirin for the initial acute phase treatment. The early treatment group consisted of 94 patients who received treatment before 5 days of fever, and the conventional group consisted of 94 patients who were treated on or after day 5. The patients' sex, age, laboratory findings, total duration of fever, duration of fever after initial IVIG, need for additional IVIG and coronary artery status were noted. Result : There were no significant differences between the two groups in sex ratio and age. No significant differences were noted in the level of WBC count, ESR, CRP, serum albumin, LDH, total duration of fever and coronary abnormality. But the value of ALT($151.8{\pm}17.3$ vs. $81.9{\pm}13.4$, P=0.002), duration of fever after initial IVIG ($3.8{\pm}0.5days$ vs. $2.1{\pm}0.2days$, P=0.003), and rate of additional IVIG (15.9% vs. 6.3%, P=0.037) were significantly higher in the early treatment group. There was no significant difference in initial dose of IVIG, but dosage of aspirin was lower in early treatment group (P=0.037). Conclusion : There is no evidence that early treatment of IVIG has greater efficacy in preventing cardiac sequelae than conventional treatment. In addition, early treatment is likely to result in a greater requirement for additional IVIG treatment.

• Journal of Biomedical Engineering Research
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• v.23 no.2
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• pp.147-153
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• 2002

The purpose of this study was to evacuate the effect of different types of Poly(lactic-co-glycolic acid) (PLGA) scaffolds on the formation of human auricular and septal cartilages. All of the scaffolds were formed in a tubular shape for potential application for artificial trachea or esophagus with either 110,000 g/mol PLGA. 220,000 g/mol PLGA. or a combination of both. In order to maintain the tubular shape in vivo, two methods were used. One method was inserting polyethylene tube at the center of scaffolds made of 110,000 g/mol PLGA. The other method involved combination of the two different molecular weight PLGA's. The inner surface of tubular shaped scaffold made with 110,000 g/mol PLGA was coated with 220,000 9/mol PLGA to give more mechanical rigidity. Elastic cartilage was taken from the ear of a patient aged under 20 nears old and hyaline cartilage was taken from the nasal septum. The chondrocytes were then isolated. After second passage, the chondrocytes were seeded on the PLGA scaffolds followed by in vitro culture for one week. The cells-PLGA scaffold complex were implanted subcutaneously on the back of nude mice for 8 weeks. The tissue engineered cartilages were separated from nude mice and examined histologically after staining with the Hematoxylin Eosin. The morphology of the scaffolds were examined by scanning electron microscopy. The pores were well formed and uniformly distributed in the various PLGA scaffolds. After 8 weeks in vivo culture, cartilage was well formed with 110,000 g/mol PLGA. however lumen had collapsed. In contrast. a minimal amount of neocartilage was formed with 220,000 g/mol PLGA, while the architecture of scaffold and lumen were well preserved. Elastic cartilage formed more neocartilage than hyaline. Hyaline and elastic neocartilage were well formed on 110,000 g/mol PLGA with the polyethylene tube, exhibiting mature chondrocytes and preservation of the tubular shape. It was found that 110,000 g/mol PLGA was more appropriate for cartilage formation but higher molecular weight polymer was necessary to maintain the three dimensional shape of the scaffold.

• Radiation Oncology Journal
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• v.11 no.1
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• pp.29-34
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• 1993

Experiments have been carried out with C3H mouse fibrosarcoma (FSa II) to determine the effect of different sequence and time intervals between irradiation and administration of cis-diammihedichloroplatinum (cis-DDP) with gross tumors (6 mm in diameter), microscopic tumors (3 days after transplantation of $10^3$ cells) and cells in culture. The drug was administered either 24, 12, 8, 4, 2, 1, 0.5 hour before irradiation, immediately before irradiation, or 0.5, 1, 2, 4, 8, 12, 24 hours after irradiation. In case of in vivo studies, tumor growth delay was used as an end point. Clonogenic cell surviving fraction was used for in vitro studies. Tumor growth delay for gross tumor after 10 Gy radiation plus 10 mg/kg cis-DDP ranged from 6.3 to 10.66 days and the enhancement ratio ranged from 1.37 to 2.23. The most effective combination was when cis-DDP was given 4 hours before irradiation. Tumor growth delay for microscopic tumor after 5 Gy of radiation and 5 mg/kg of cis-DDP ranged from 3.55 to 11.98 days with enhancement ratio from 2.05 to 6.92. Microscopic tumors showed response significantly greater than additive in every time interval and the most effective treatments were when cis-DDP was given 2 and 1 hour before irradiation. In in vitro experiment, the surviving fraction after 6 Gy of radiation and 1 hour exposure to 4 ${\mu}M$ cis-DDP fluctuated as a function of time between treatments, but the difference between maximum and minimum surviving fractions was very small. According to the above results the sequence and time interval between irradiation and chemotherapy is very critical especially for the management of microscopic tumors as in the case of postoperative adjuvant treatment.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.12 no.2
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• pp.199-206
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• 2009

Purpose: To analyze the clinical spectrum of posttransplantation lymphoproliferative disorder (PTLD) after liver transplantation in children. Methods: From January 1988 to June 2009, we retrospectively reviewed the medical records of 8 PTLD cases among 148 pediatric patients underwent liver transplantation. The age at transplantation, time of presentation after transplantation, clinical manifestations, histologic diagnosis, results of EBV (Epstein-Barr virus) assessments, managements and outcomes of PTLD were investigated. Results: The prevalence of PTLD in liver transplant pediatric recipients was 5.4% (8 of 148). The mean age of patients was 25.4${\pm}$21.3 months (range 10 to 67 months). Seven of 8 patients (87.5%) underwent liver transplantation before 1 year of age. The common clinical presentations were persistent fever (8 of 8, 100%) and bloody diarrhea (6 of 8, 75%). PTLD was diagnosed with gastrointestinal endoscopic biopsies in five patients and surgical biopsies in three. Histologic findings showed early lesion in three patients, polymorphic in two, and monomorphic in three. Burkitt lymphoma and lymphoblastic lymphoma were found in two of 3 monomorphic patients. Seven of 8 patients were found with EBV-positive. Eight patients were treated with dose reduction of immunosuppressants and infusion of ganciclovir. Rituximab was added to four patients. PTLD were successfully managed in all patients except one who died of sepsis during chemotherapy. Conclusion: Major risk factor of PTLD was to undergo liver transplantation before 1 year of age. Continuous monitoring for EBV viral load and gastrointestinal endoscopic biopsy may be useful to early detection of PTLD.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.12 no.2
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• pp.163-170
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• 2009

Purpose: Intussusception is the most common cause of intestinal obstruction in young children. Although intussusceptions are easily treated, some intussusceptions with or without a pathologic lead point (PLP) often recur. In this study, we analyzed the clinical characteristics and prognosis of recurrent intussusceptions (RI), the frequency of the PLP, and correlation between RI with PLP. Methods: The medical records of 144 patients, among 590 patients with intussusceptions who had been admitted to the Department of Pediatrics and Pediatric Surgery of Dankook University Hospital between May 1994 and June 2009 were reviewed retrospectively. Results: The overall recurrence rate of intussusceptions in this study was 9.2%. The mean interval between the initial occurrence and the first recurrent attack was 130${\pm}$175 days (range, 12 hours to 3 years). There was no statistically significant difference in the recurrence rate among patients who underwent air, barium, and manual reduction (p=0.131). Eighty-seven cases (92.6%) of RI had a successful reduction by the use of non-operative techniques. A PLP was present in 18 patients (3.0%). The most common PLP was intestinal lymphoid hyperplasia, followed by Meckel's diverticulum, duplication cyst, intestinal polyp, and adenomyoma. The mean number of intussusceptions was 4.7${\pm}$1.9 in 7 patients with PLP, which was significantly higher than (2.4${\pm}$0.9) patients without a PLP (p=0.023). The mean duration of recurrences was 17.4${\pm}$19.8 months (range, 2 days to 72 months). Conclusion: A careful search for a PLP should be performed to prevent recurrence of intussusception, especially when intussusception has recurred more than three times.

• Childhood Kidney Diseases
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• v.1 no.2
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• pp.170-175
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• 1997

Purpose : Hemolytic uremic syndrome(HUS), known as a most common cause of childhood renal failure in western countries, has been a relatively rare disease in Korea. Although the reported cases were not related to any specific cause in Korea, there was an outbreak of HUS with bloody diarrhea in Japan last year. We report here that we experienced the several typical HUS last year. Patients : From Jan.1996 to Dec. 1996, five patients were diagnosed as HUS at Samsung Seoul Medical Center, Dept. Pediatrics. Results : 1) The age of onset was below 3 years in 3 cases and above 9 years in 2 cases. 2) All the cases happened between summer and autumn. Three patients had domestic travel and 4 patients drank well or spring water before the symptoms. 3) The clinical manifestation was generalized edema, oliguria, anuria and hematuria. The bloody diarrhea were present in 5 cases and 1 patient had operation with the impression of appendicitis. 4) There was no bacteria which was isolated from the blood or stool samples. 5) Renal biopsies were performed in 2 cases, because of protracted clinical course. One showed microthrombotic angiopathy and the other cortical necrosis with necrotizing glomeruli. 6) Complete recovery was the outcome in 4 cases and one case progressed to chronic renal failure. Conclusion : In conclusion, typical HUS associated with bloody diarrhea, epidemic and good prognosis can be found in Korea and careful surveillance of the pre-clinical cases will be necessary.

• Journal of the Korean Society of Radiology
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• v.5 no.1
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• pp.37-49
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• 2011

To examine the possible changes in the SNRs, CNRs, and ADC values for lumbar spines with metastasis based on the DW images before and after contrast agent injection taken from metastatic spinal cancer patients using a 1.5 T MR machine. The quantitative analysis revealed that in case of spinal cancer subjects, both SNRs and CNRs at all of those assessed locations significantly increased on the DWI after contrast agent injection compared to before, while on the ADC map images, SNRs significantly decreased. On the other hand, significantly decreased ADC values at all the assessed locations were found on the ADC map images. With reference to the normal group, significantly increased SNRs were found at all of the assessed locations on the DWI image after injection compared to before, while significantly decreased SNRs were found on the ADC map images. Also, significantly decreased ADC values at all the assessed locations were found on the ADC map images. For the qualitative analysis, after contrast agent injection, significantly increased signal intensities were found at the locations with spinal cancer on the DWI. In contrast, significantly decreased signal intensities were found on the ADC map images. The implication from the results showing that SNR and CNR significantly increased while ADC value significantly decreased at, above, and below the location of metastatic spinal cancer on DWI after contrast agent injection is that DWI obtained after contrast agent injection can be made available for wider application to vertebral disorders.

• 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.