• Journal of Genetic Medicine
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• v.3 no.1
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• pp.29-32
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• 1999

The Apolipoprotein E type 4 allele (ApoE ${\varepsilon}4$) is genetically associated with the common late onset familial and sporadic forms of Alzheimer's disease. The BchE-k variant, which is the common variant of the BchE gene, has been reported to show allelic association with AD in subjects who are also carriers of the ${\varepsilon}4$ allele of the ApoE, especially in subjects over the age of 75. This study was performed to evaluate the distribution of the ApoE and the BchE genotypes in the healthy and AD groups and to evaluate the synergy between the BchE-k variant and the ApoE ${\varepsilon}4$ in AD. The ApoE and the BchE genotypes were determined in DNA samples from 610 healthy people and 60 LOAD patients by using ARMS by standard agarose gel electrophoresis. The effect of the ApoE ${\varepsilon}4$ was closely related to AD(p<0.05). A comparison between the AD patients and the healthy individuals, both with the ${\varepsilon}4$ allele, indicated an interaction between the BchE-k and the ApoE ${\varepsilon}4$(p<0.05). The association of the BchE-k with AD was limited to carriers of the ApoE ${\varepsilon}4$ allele, among whom the presence of the BchE-k gave an odds ratio of AD 3.48 (95% C.I. 1.3-9.2). Therefore, these results suggested that further evidence of an association between the ApoE ${\varepsilon}4$ and LOAD, and the BchE-k acts in synergy with the ApoE ${\varepsilon}4$ as a susceptibility gene for AD.

• Neonatal Medicine
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• v.15 no.1
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• pp.54-60
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• 2008

Purpose : To set up an appropriate treatment plan for neonatal sepsis by investigating changes in pathogens and antibiotic sensitivities. Methods : The medical records of very low birth weight infants (VLBWI) admitted to the neonatal intensive care unit (NICU) of the Eulji University Hospital between January 2000 and June 2006 were retrospectively reviewed. The culture reports were analyzed for causative microorganisms and antibiotic sensitivities. Results : Among 164 neonates, 19 neonates (11.6%) had 26 episodes of culture-proven sepsis. Very late onset sepsis was the most common type. The dominant pathogens of sepsis included Klebsiella pneumoniae, Streptococcus spp., coagulase negative Staphylococcus and Enterobacter spp., and were mostly multi-drug resistant. Conclusion : For the appropriate treatment of neonatal sepsis, proper use of antibiotics through the periodic review and understanding of changes of the microorganisms and antimicrobial sensitivities is necessary to prevent multi-drug resistant microorganisms and to avoid excessive use of broad-spectrum empiric antibiotics.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.18 no.1
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• pp.30-34
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• 2018

Niemann Pick type C disease (NPC) is an inherited progressive neurodegenerative disorder, due to defects of intracellular lipid trafficking and storage. Hepatosplenomegaly may prevail, while progressive neurodegenerative symptoms such as cerebellar involvement, dystonia, vertical supranuclear ophthalmoplegia, cataplexy, and eventually seizures starting at juvenile or late infantile period may accompany after normal early development. Here we describe a 3-year-old Korean boy with NPC who presented with splenomegaly at age 3. Liver biopsy showed characteristic foamy cell stained by periodic acid-schiff, and molecular analysis for NPC1 identified the compound heterozygous mutations, novel mutation of c.1631G>A (p.Trp544Ter) and c.2662C>T (p. Pro888Ser) as a known mutation. Filipin was strongly stained with unesterified cellular cholesterol in the patient's skin fibroblasts. The patient has received migulstat since age 3 years and his long-term outcome is needed to be observed.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.113-113
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• 2000

직접천이형 wide band gap(3.4eV) 반도체중의 하나인 GaN를 청색 및 자외선 laser diode, 고출력 전자장비 등으로 응용하기 위해서는 낮은 접합저항을 갖는 Ohmic contact이 선행되어야 한다. 그러나 만족할만한 p-type GaN의 Ohmic contact은 아직 실현되고 있지 못하며, 이는 GaN와 접합 금속과의 구체적인 반응의 연구를 필요로 한다. 본 연구에서 앞서 Pt, Pt, Ni등의 late transition metal을 p-GaN에 접합시킨 결과 이들은 접합 당시 비교적 평탄하나 후열 처리과정에서 비교적 낮은 온도에서 기판과 열팽창계수의 차이로 인하여 평탄성을 잃어버리면서 barrier height가 증가한다는 사실을 확인하였다. 따라서 본 연구에서는 이러한 열적 불안정성을 극복하기 위하여 Ni과 Pd를 차례로 증착하고 가열하면서 interfacial reaction, film morphology, Fermi level의 움직임을 monchromatic XPS(x-ray photoelectron spectroscopy) 와 SAM(scanning Auger microscopy) 그리고 ex-situ AFM을 이용하여 밝히고자 하였다. 특히 후열처리에 의한 계면 반응에 수반되는 구성 금속원소 간의 합금현상과 금속 층의 평탄성이 밀접한 관계가 있다는 것을 확인하였다. 이러한 합금과정에서 나타나는 금속원소들의 중심 준위의 이동을 체계적으로 규명하기 위해서 Pd1-xNix와 Pd1-xGax 합금들의 표준시료를 arc melting method로 만들어 농도에 따른 금속원소들의 중심 준위의 이동을 측정하여, Pd/Ni/p-GaN 및 Ni/Pd/p-GaN 계에서 열처리 온도에 따른 interfacial reaction을 확인하였다. 그 결과 두 계가 상온에서 nitride 및 alloy를 형성하지 않고 고르게 증착되고, 열처리 온도를 40$0^{\circ}C$에서 $650^{\circ}C$까지 증가시킴에 따라 계면반응의 부산물인 metallic Ga은 증가하고 있으마 nitride는 여전히 형성되지 않는 것을 확인하였다. 증착당시 Ni이 계면에 있는 Pd/Ni/p-GaN의 경우에는 52$0^{\circ}C$까지의 열처리에 의하여 Ni과 Pd가 골고루 섞이고 그 평탄성도 유지되고 barier height의 변화도 없었다. 더 높은 $650^{\circ}C$ 가열에 의해서는 surface free energy가 작은 Ga의 활발한 편석 현상으로 인해 표면은 Ga이 풍부한 Pd-Ga의 합금층으로 덮이고, 동시에 작은 pinhole들이 발생하며 barrier height도 0.3eV 가량 증가하게 된다. 반면에 증착당시 Pd이 계면에 있는 Ni/Pd/p-GaN의 경우에는 40$0^{\circ}C$의 가열까지는 두 금속이 그들 계면에서부터 섞이나, 52$0^{\circ}C$의 가열에 의해 이미 barrier height가 0.2eV 가량 증가하기 시작하였다. 더 높은 $650^{\circ}C$가열에 의해서는 커다란 pinhole, 0.5eV 가량의 barrier height 증가, Pd clustering이 동시에 관찰되었다. 따라서 Ni과 Pd의 일함수는 물론 thermal expansion coefficient가 거의 같으며 surface free energy도 거의 일치한다는 점을 감안하면, 이렇게 뚜렷한 열적 안정성의 차이는 GaN와 contact metal과의 반응시작 온도(disruption onset temperature)의 차이에 기인함을 알 수 있었다. 즉 계면에서의 반응에 의해 편석되는 Ga에 의해 박막의 strain이 이완되면, pinhole 등의 박막결함이 줄어 들고, 이는 계면의 N의 out-diffusion을 방지하여 p-type GaN의 barrier height 증가를 막게 된다.

• Clinical and Experimental Pediatrics
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• v.46 no.12
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• pp.1224-1229
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• 2003

Purpose : Bacterial meningitis is a serious disease, especially in the neonatal period, and it carries a significant degree of mortality and morbidity. Group B streptococcus(GBS) is a common cause of neonatal bacterial meningitis. The purpose of this study was to evaluate the clinical manifestations, treatment results and complications of GBS meningitis. Methods : We analyzed 29 cases retrospectively who had been admitted to the pediatric ward or NICU in Asan Medical Center from May 1990 to January 2002. They had proven GBS in culture or latex agglutination test in CSF. Results : The male to female ratio was 1 : 1.9. There were two cases of early onset type and 27 cases of late onset type. All cases had normal birth weight with full term at delivery. The perinatal predisposing factors were premature rupture of membrane(two cases), and maternal colonization(two cases). The most common presenting symptoms were fever and irritability. Associated diseases were GBS sepsis(21 cases). There was relatively high sensitivity to penicillin derivatives. There were abnormal brain CT or MRI findings in 16 cases(64%), such as infarction, encephalomalatic change, effusion, hydrocephalus, hemorrhage and abscess. The intensive care unit admission rate and the incidence of DIC were higher in the group with complications. Two cases were discharged against advice. Conclusion : We recommend early detection and active treatment in Group B streptococcal meningitis to improve the prognosis.

• Pediatric Infection and Vaccine
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• v.6 no.2
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• pp.194-202
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• 1999

Background : Group B ${\beta}$-hemolytic Streptococcus(GBS) has been the major pathogen of neonatal sepsis in western country. In contrast, GBS has played little role in neonatal sepsis in Korea. But recently, neonatal GBS infections are encountered more frequently. It is important to characterize the clinical and epidemiological features of GBS infection in Korean children. Methods: We reviewed retrospectively the medical records of twenty-seven infants and children with GBS infection experienced at the Seoul National University Children's Hospital during 14 year-period from June, 1985 to June, 1999. Fourteen strains isolated from blood and cerebrospinal fluid were serotyped. Minimum inhibitory concentrations of 10 strains were determined by agar dilution method for penicillin, ampicillin, ampicillin with sulbactam, cefarolin, cefuroxime, and cefuiaxone. Results: The numbers of cases with GBS infection increased in 1990s. Among twenty seven cases, twenty-five cases were under three months of age and both of two cases with underlying disease occurred at three years of age. All neonatal infections were late-onset type and meningitis predominated. Serotypes were III(6 strain), Ib(4), Ia(l) and V(2). All of the strain were susceptible to all of the antibiotics tested. Conclusion: GBS infections in infants were increasingly recognized. GBS should be considered as an etiological agent of neonatal sepsis or meningitis in Korea. Maternal screening and prophylactic antibiotic therapy may be considered.

• The Korean Journal of Applied Statistics
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• v.21 no.1
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• pp.81-94
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• 2008

Family-based tests such as the transmission and disequilibrium tests(TDT) have proved to be powerful tools in the search for disease genes. Unlike case-control studies, the tests are not affected by population admixture, which can lead to spurious association of multiple highly linked makers with disease-susceptible genes. Those tests have largely required knowledge of parental marker genotypes. However, parental data are often not available for late-onset diseases. In this article we propose sib-TDTs that overcome this problem by use of marker data from unaffected sib(s) instead of parents. To do this end, we fist defined a Mantel-Haenszel-type statistic for each haplotype and then proposed two tests based on this statistic. Simulation studies suggest that the proposed tests are robust to population admixture and are monotone increasing as a relative risk increases irrespective of mode of inheritance. We also illustrated the proposed tests with data adopted from Yonsei Cardiovascular Genome Center.

• Clinical and Experimental Pediatrics
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• v.51 no.9
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• pp.964-970
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• 2008

Purpose : Methylmalonic aciduria (MMA) and propionic aciduria (PA) are inborn errors in the catabolism of branched-chain amino acids. The study was undertaken to investigate the genotypes and clinical features of Korean patients with MMA and PA. Methods : This study examined 12 patients with MMA and eight with PA. We analyzed various clinical features, laboratory findings, treatments, and neuro-developmental outcomes. Diagnoses were based on the presence of characteristic compounds detected by amino acid analysis in serum and organic acid analysis in urine. Mutation analysis was performed in the genes of MUT, MMAA, MMAB, and MMACHC for MMA and PCCA and PCCB for PA. Results : Among the 20 patients, six patients were diagnosed before one month of age and nine patients were diagnosed after the newborn period. Five patients were diagnosed via a neonatal screening test. Patients with early-onset forms had more severe illness at presentation and generally poor outcomes. A favorable outcome was obtained in 55% patients; most of them were of a late-onset type or diagnosed by neonatal mass screening test without symptoms. Genotypes were confirmed in all patients with MMA. We detected 11 different mutations by MUT gene analysis in 10 patients, and three different mutations in MMACHC genes in two patients. PCCA and PCCB gene mutations were identified in 14 of the 16 alleles, in eight patients with PA. Conclusion : Organic aciduria is a fatal disease; however, better outcomes are expected whenever early diagnosis and prompt management are made possible. Mutation analysis is useful for confirming diagnoses and planning management strategies.

• Clinical and Experimental Pediatrics
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• v.53 no.4
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• pp.538-547
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• 2010

Purpose : This study aims to compare the outcome of total body irradiation (TBI)- or non-TBI-containing conditioning regimens for leukemia in children. Methods : We retrospectively evaluated 77 children conditioned with TBI (n=40) or non-TBI (n=37) regimens, transplanted at Chonnam National University Hospital between January 1996 and December 2007. The type of transplantation, disease status at the time of transplant, conditioning regimen, engraftment kinetics, development of graft-versus-host disease (GVHD), complications, cause of deaths, overall survival (OS), and event-free survival (EFS) were compared between the 2 groups. Results : Among 34 patients with acute lymphoblastic leukemia (ALL), 28 (82.4%) were in the TBI group, while 72.7% (24/33) of patients with myeloid leukemia were in the non-TBI group. Although the 5-year EFS of the 2 groups was similar for all patients (62% vs 63%), the TBI group showed a better 5-year EFS than the non-TBI group when only ALL patients were analyzed (65% vs 17%; $P$=0.005). In acute myelogenous leukemia patients, the non-TBI group had better survival tendency (73% vs 38%; $P$=0.089). The incidence of GVHD, engraftment, survival, cause of death, and late complications was not different between the 2 groups. Conclusion : The TBI and non-TBI groups showed comparable results, but the TBI group showed a significantly higher 5-year EFS than the non-TBI group in ALL patients. Further prospective, randomized controlled studies involving larger number of patients are needed to assess the late-onset complications and to compare the socioeconomic quality of life.

• Sleep Medicine and Psychophysiology
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• v.22 no.2
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• pp.57-63
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• 2015

Background and Objectives: Internet addiction is an increasing problem in Korea. The previous studies in this area have targeted adolescents and young adults. This study was conducted to examine the risk of internet addiction in Korean adults and the effect of internet addiction on circadian rhythm. Materials and Methods: For this study, 508 subjects were chosen through population proportional sampling to represent the adult population in Korea, 325 of whom were included based on the Alcohol Use Disorder Identification Test-Korea (Audit-K), Zung's Self-Rating Depression Scale (SDS), drug use in the past year, and suicide attempts. In these subjects, sociodemographic factors including age, gender, and residential area were analyzed, and Young's Internet Addiction Scale (IAS), Morningness-Eveningness Questionnaire (MEQ), and an online survey examining sleep onset time on weekdays and weekends, wake-up time, and caffeinated drink intake were executed. Results: Of the 325 subjects, 136 (41.8%) belonged to a high-risk internet addiction group ($IAS{\geq}40$), and 189 (58.2%) belonged to a normal group (IAS < 40). There was a high proportion of male subjects (p = 0.03) in the high-risk group compared to the normal group. There was a high proportion of younger subjects (p = 0.055) in the high-risk group compared to the normal group, but this difference was not statistically significant. Compared to the normal group, there was a high proportion of the evening type ($MEQ{\leq}41$) in the high-risk group (p = 0.024), who also showed a high proportion of caffeinated drink intake (p < 0.001). Also, the high-risk group was found to go to bed and wake up late, but there was no statistically significant difference with the normal group. Conclusion: This study showed that many adults have a high-risk of internet addiction, and there was a significant correlation between internet addiction and sleep in adult, as has been found in adolescents and early adults. In the future, a longitudinal study will be needed to verify the causal relationship between internet addiction and morningness-eveningness.