Pilocarpine-induced rat epilepsy model is an established animal model that mimics medial temporal lobe epilepsy in humans. The purpose of this study was to investigate neuroimaging abnormalities in various stages of epileptogenesis and to correlate them with seizure severity in pilocarpine-induced rat epilepsy model. Fifty male Sprague-Dawley rats were subject to continuous video and electroencephalographic monitoring after inducing status epilepticus (SE) and seizure severity was estimated by frequency and total durations of class 3 to 5 spontaneous recurrent seizures (SRS) by modified Racine's classification. The 7.0 Tesla magnetic resonance imaging (MRI) with high resolution flurodeoxyglucose positron emission tomography (FDG-PET) was performed at 3 hours, 1, 3, 7 days and 4 weeks after the initial insult. The initial SRS was observed 9.7±1.3 days after the pilocarpine injection. MRI revealed an abnormal T2 signal change with swelling in both hippocampi and amygdala in acute (day 1 after injection) and latent phases (days 3 and 7), in association with PET hypometabolism in these areas. Interestingly, the mean frequency of class 3 to 5 SRS was positively correlated with abnormal T2 signals in hippocampal area at 3 days. SRS duration became longer with more decreased glucose metabolism in both hippocampi and amygdala at 7 days after pilocarpine injection. This study indicates that development and severity of SRS at chronic phase could be closely related with structural and functional changes in hippocampus during the latent period, a pre-epileptic stage.
Amygdala ; Animals ; Classification ; Epilepsy* ; Epilepsy, Temporal Lobe ; Glucose ; Hippocampus ; Humans ; Magnetic Resonance Imaging ; Male ; Metabolism ; Models, Animal ; Neuroimaging ; Pilocarpine ; Positron-Emission Tomography ; Rats ; Rats, Sprague-Dawley ; Seizures ; Status Epilepticus

BACKGROUND: Technique failure is an important issue for peritoneal dialysis (PD) patients. In this study, we aimed to analyze technique failure rate in detail and to determine the predictors for technique failure in Korea. METHODS: We identified all patients who had started dialysis between January 1, 2005, and December 31, 2008, in Korea, using the Korean Health Insurance Review and Assessment Service database. A total of 7,614 PD patients were included, and the median follow-up was 24.9 months. RESULTS: The crude incidence rates of technique failure in PD patients were 54.1 per 1,000 patient-years. The cumulative 1-, 2-, and 3-year technique failure rates of PD patients were 4.9%, 10.3%, and 15.6%, respectively. However, those technique failure rates by Kaplan–Meier analysis were overestimated compared with the values by competing risks analysis, and the differences increased with the follow-up period. In multivariate analyses, diabetes mellitus and Medical Aid as a crude reflection of low socioeconomic status were independent risk factors in both the Cox proportional hazard model and Fine and Gray subdistribution model. In addition, cancer was independently associated with a lower risk of technique failure in the Fine and Gray model. CONCLUSION: Technique failure was a major concern in patients initiating PD in Korea, especially in diabetic patients and Medical Aid beneficiaries. The results of our study offer a basis for risk stratification for technique failure.
Diabetes Mellitus ; Dialysis ; Follow-Up Studies ; Humans ; Incidence ; Insurance, Health ; Korea ; Multivariate Analysis ; Peritoneal Dialysis* ; Proportional Hazards Models ; Risk Factors ; Social Class

PURPOSE: The aim of this study was to investigate whether the survival rate among Korean dialysis patients changed during the period between 2005 and 2008 in Korea. MATERIALS AND METHODS: A total of 32357 patients who began dialysis between January 1, 2005 and December 31, 2008 were eligible for analysis. Baseline demographics, comorbidities, and mortality data were obtained from the database of the Health Insurance Review & Assessment Service. RESULTS: Kaplan-Meier curves according to the year of dialysis initiation showed that the survival rate was significantly different (log-rank test, p=0.005), most notably among peritoneal dialysis (PD) patients (p<0.001), although not among hemodialysis (HD) patients (p=0.497). In multivariate analysis, however, patients initiating either HD or PD in 2008 also had a significantly lower risk of mortality compared to those who began dialysis in 2005. Subgroup survival analysis among patients initiating dialysis in 2008 revealed that the survival rate of PD patients was significantly higher than that of HD patients (p=0.001), and the survival benefit of PD over HD remained in non-diabetic patients aged less than 65 years after adjustment of covariates. CONCLUSION: Survival of Korean patients initiating dialysis from 2005 to 2008 has improved over time, particularly in PD patients. In addition, survival rates among patients initiating dialysis in 2008 were different according to patients' age and diabetes, thus we need to consider these factors when dialysis modality should be chosen.
Adult ; Aged ; Comorbidity ; Female ; Humans ; Kaplan-Meier Estimate ; Kidney Failure, Chronic/*mortality/therapy ; Male ; Middle Aged ; Multivariate Analysis ; Peritoneal Dialysis/*statistics & numerical data ; Registries ; Renal Dialysis/*statistics & numerical data ; Republic of Korea/epidemiology ; Risk ; Survival Analysis ; Survival Rate/*trends ; Treatment Outcome

BACKGROUND: Although patients with end-stage renal disease (ESRD) experience excess mortality compared with the general population, the standardized mortality ratio (SMR) for Korean patients on dialysis has not yet been investigated. In this study, we evaluated the SMR among all Korean ESRD patients on maintenance ialysis in 2009 and 2010, and compared it according to age categories, sex, and dialysis modality. METHODS: We used data from all patients on maintenance dialysis between January 1, 2009 and December 31, 2010 in Korea using the database of the Korean Health Insurance Review and Assessment Service, and the SMR was determined by calculating of the ratio between the number of actual deaths and expected deaths. RESULTS: A total of 45,568 patients in 2009 and 48,170 patients in 2010 were included in the analysis. The overall age- and sex-adjusted SMR was 10.3 [95% confidence interval (CI), 10.0-10.6] in 2009 and 10.9 (95% CI, 10.7-11.2) in 2010. The SMR for females was much higher than for males. The SMR gradually decreased with increasing age groups. The overall SMR for maintenance hemodialysis patients was lower than that of peritoneal dialysis patients. CONCLUSION: The SMR among Korean ESRD patients is likely to be higher than in other countries. Further evaluation is needed to attempt to improve the outcomes.
Dialysis* ; Female ; Humans ; Insurance, Health ; Kidney Failure, Chronic ; Korea ; Male ; Mortality* ; Peritoneal Dialysis ; Renal Dialysis

BACKGROUND: During the 2009 influenza pandemic in Korea, school-age children were mostly attacked by the novel influenza A virus (H1N1). Nevertheless, there is limited information on the cumulative incidence of the 2009 influenza pandemic among school populations. The aim of this study was to estimate the incidence of 2009 H1N1 influenza and influenza-like illness (ILI), and characterize the epidemiology among school-based populations in Korea. MATERIALS AND METHODS: This study analyzed the data collected by the daily school influenza reporting system for laboratory-confirmed influenza (H1N1 2009 pdm) and ILI in elementary, middle and high schools in Korea during the period, July 1 to December 20, 2009. RESULTS: Between July 1 and December 20, 2009, a total of 525,668 cases of H1N1 2009 pdm were reported from the schools analyzed. The cumulative incidence of H1N1 2009 pdm was highest in elementary school children between 8 and 13 years of age (11,058 per 100,000 population), followed by middle school students between 14 and 16 years of age (10,080 per 100,000), and high school students between 17 and 19 years of age (8,886 per 100,000). With the alignment of the epidemic curves by the three levels of school education, the age group-specific differences in the timing of the infection became apparent. The infections peaked 1 week earlier in both middle and high school students (November 3, 2009) than in elementary school children (November 10, 2009). The infections occurred an average of 7.3 [95% confidence interval(CI): 7.2-7.4] and 3.4 (95% CI: 3.3-3.5) days earlier in the middle and high school students, respectively, than elementary school children (P<0.001). The overall trend of the epidemic waves from the school reporting system data was similar to that of the national surveillance date from the Korea Centers for Disease Control and Prevention. CONCLUSIONS: This study suggests that during the 2009 pandemic, one student in every 10 was infected with H1N1 2009 pdm, which is double that estimated from the national surveillance data. In addition, middle and high school students were important drivers of H1N1 2009 pdm transmission in 2009. During the 2009 influenza pandemic, the daily school reporting system provided valuable information for estimating the incidence as well as the epidemiological characteristics in school-based populations.
Centers for Disease Control and Prevention (U.S.) ; Child ; Humans ; Incidence ; Influenza A virus ; Influenza, Human ; Korea ; Pandemics

Cancer development is accompanied by genetic events like losses, gains and amplification of certain chromosome regions or alterations of chromatin structure. Array-based CGH (Array-CGH) is a highly comprehensive, sensitive and fast technique to allow investigation of general changes in target oncogenes and tumor suppressor genes. Recently, the prevalence of colon cancer is rapidly increasing in Korea and now it is the fourth leading cause of cancer death. So, the purpose of this study is to examine genomic alterations in colon cancer cell lines and to search novel genes which might be related to the development of colon cancer. In this study, genomic alterations are analyzed by using array-CGH in three colon cell lines from Korean, SNU-81, SNU-407 and SNU-1047. We observed numerous chromosomal imbalances from all cell lines. The common chromosomal gains were observed in 1p36.33, 1q22, 1q32.1, 2q35, 8p12, 8q22.3, 14q32.33, 16p13.3, and 16q24. Common chromosomal losses were found in 4q22.1, 9q13, 14q21.1, 14q32.33, 20p12.1, Xq21.1, and Yq11.223. Gains of 1p, 2q, 8p, and 8q or losses of 4q, 14q and 20p are already known to be associated with the colon cancer development. For gene alterations, we could see gains of some genes such as ELF3 and AAMP, which were already reported to be associated with colon cancer. Also, we could find some gene alterations which were known to be associated with other cancer types. These genes were GON4L, RNPEP, TMBIM1, TIMM17A, GPBAR1, PPP1R13B and SOX8. Besides, we found alterations of new genes such as PKND and LEPROTL1. The association of these genes with colon cancer is first demonstrated here. These genes may be the novel candidate genes functioning in the development of colon cancer. In conclusion, array-CGH demonstrated the complexity of genetic aberrations in several colon cell lines. These data about the patterns of genomic alterations could be a basic step for understanding more detailed genetic events in the carcinogenesis and also provide information about possible target genes for diagnosis and treatment in colon cancer.
Cell Line ; Chromatin ; Colon ; Colonic Neoplasms ; Genes, Tumor Suppressor ; Korea ; Nucleic Acid Hybridization ; Oncogenes ; Prevalence

Retinoblastoma is the most common intraocular malignancy in young children, arising in approximately 1 per 20,000 live births. Although it is established that the functional loss of both alleles of the RB1 gene is a prerequisite for the development of retinoblastoma, little is known about the genetic events that are required for tumor progression. To screen the genomic aberrations, two retinoblastoma cell lines, Y-79 and WERI-Rb-1, were analysed by using array-CGH. As a result, gains of AHRR, EXOC3, CEP72, TRIP13, TERT, SEMA5A, TAS2R1, MARCH6, CTNND2, CDH12, NHLRC1, TPMT, AOF1, FANCC, NCBP1, XPA, TGFBR1, BAAT, MRPL50, ZNF189, ALDOB, ABCA1, FCMD, TAL2, ZNF462, COL27A1, ORM1, ORM2, AKNA, ASTN2, TRIM32, GSN, STOM, LHX2, PBX3, ABL1, FIBCD1, WNK4, CCDC56, CNT1, BECN1, PSME3, AOC2, LOXHD1, ST8SIA5, SMAD2, KIAA0427, COL18A1, COL6A2, FTCD and LSS were found in both cell lines. Lost clones detected in both cell lines were RB1, ZDHHC3, EXOSC7, CLEC3B, CACNA2D3, DEFB106A, FAM90A6P, FAM90A7, ZMYND11, LARP5, GTPBP4, IDI2, IDI1, KLF6, AKR1CL2, FBXO18, IL15RA, IL2RA, TAF3, GATA3, CUGBP2, DHTKD1, SEC61A2, NUDT5, ITGA8, PTER, C1QL3, RSU1, DNMT2, PTPLA, PLXDC2, NEBL, MLLT10, DNAJC1, PIP5K2A, PRTFDC1, NRP1, PARD3, MGMT, RFP2OS, RFP2, KCNRG, IGHV, CDH19, TXNDC10 and RTTN. Through this study, it is confirmed that many genomic aberrations are involved in the development and progression of retinoblastoma. Genomic profiling of retinoblastoma cell lines by array-CGH revealed numerous imbalanced regions and novel candidate genes. These data provide a basis for more detailed molecular characterization and testing their pathologic roles of these candidates.
Alleles ; Cell Line ; Child ; Clone Cells ; Humans ; Live Birth ; Retinoblastoma

Tissue-derived angiogenic factors are thought to play an important role in angiogenesis. Among these, SPARC and VEGF are known to be involved in physiologic and pathologic angiogenesis. However, the expression of these factors in the rabbit retina, especially in the early postnatal period, remains unclear. To determine whether these factors contribute to retinal angiogenesis in the rabbit retina, expression of SPARC and VEGF was studied by immunohistochemistry at postnatal (P) days 0, 7, 14, and 28. (1) SPARC immunoreactivity was observed in the nerve fiber layer of the medullary ray and the pigment epithelium at all ages. In whole mount preparations, SPARC immunoreactivity was noted in many astrocytes surrounding nerve fibers or blood vessels in the medullary ray. (2) VEGF immunoreactivity of variable intensity was found in ganglion cells, vascular endothelial cells, and some astrocytes. VEGF immunoreactivity was detected from P0, was maintained until P14, and was markedly lower at P28. The spatial pattern of SPARC expression suggests that SPARC functions as a crucial regulator that determines the selective location of the retinal angiogenic process. The temporal pattern of VEGF expression suggests that VEGF is a major angiogenic factor involved in rabbit retinal angiogenesis.
Angiogenesis Inducing Agents ; Astrocytes ; Blood Vessels ; Endothelial Cells ; Epithelium ; Ganglion Cysts ; Immunohistochemistry ; Neovascularization, Pathologic ; Nerve Fibers ; Retina ; Retinaldehyde ; Vascular Endothelial Growth Factor A

Recovery from the laryngeal dysfunction caused by the recurrent laryngeal nerve (RLN) injury is not common. Recently, we have found that PEMS treatment improved the functional recovery rate and shortened the recovery time after RLN transection and reanastomosis in rat. In this study, we compared the morphology of RLN stumps according to their laryngeal functional status to investigate 1) the nerve morphology associated with functional recovery and 2) the possible underlying mechanism of persistent laryngeal dysfunction after RLN injury. We transected left RLN and then performed primary neurorrhaphy in Sprague-Dawley rats (n = 36). They were randomly divided into PEMS and control groups. 19 animals (10 PEMS group, 7 control group and 2 normal control animals) survived until the end of the experiment were included in the morphological analysis. Both the proximal and distal segments of reanastomosed RLN were obtained and the ultrastructural study was done using transmission electron microscope. There is no prominent morphological difference between the PEMS and control groups. In the functional recovery group, the findings suggestive of nerve regeneration were prominent both in the proximal and distal segments. Many regenerating axons were also observed in the proximal segments of RLNs in non-recovery group. But findings such as degenerating axons, infiltration of macrophage and inflammatory cells, increased collagen fibrils were frequently observed in this group. Even in the distal segments of functional non-recovery group, prominent regenerative findings were observed in 9 out of 10 (4 out of 5 PEMS and all control group animals) samples. We could not find any regenerating findings in one case of the PEMS group. Through the above results, failure of the nerve regeneration is unlikely the main cause of functional non-recovery after RLN injury in rat. Possible other causes such as synkinesis or definite but inadequate nerve regeneration should be considered and needs further investigation.
Animals ; Axons ; Collagen ; Macrophages ; Nerve Regeneration* ; Rats ; Rats, Sprague-Dawley ; Recurrent Laryngeal Nerve Injuries* ; Recurrent Laryngeal Nerve* ; Synkinesis

Tyrosine hydroxylase-immunoreactive (TH-IR) neurons are known to exist in the substantia nigra pars compacta (SNpc), but not in the striatum in normal rats. In this study, injection of 6-OHDA into the 7 or 14 day neonatal rat striatum resulted in the appearance of ectopic TH-IR neurons in striatum. TH-IR cells were observed as early as postlesion day 3 and confirmed as neurons by TH/NeuN double immunohistochemistry. One or two neurons were found in most striatal sections at post-lesion day 4 where they were preferentially located in the ventro-lateral striatum, striatopallidal junction and globus pallidus. A small portion of these neurons persisted at least until post-lesion day 56, the oldest age studied. TH-IR neurons were found bilaterally in 6-OHDA-lesioned animals, but never in normal or vehicle-injected controls. To determine if these neurons resulted from stem cells, bromodeoxyuridine (BrdU) was injected daily for the first five days to label dividing cells. There was no co-localization of TH and BrdU immunoreactivity, excluding the possibility of stem cells as the source of these neurons. Although the TH-IR neurons were not numerous, their appearance following injury to the nigrostriatal system suggests that there is a capacity in neonatal brain to compensate for this lesion by upregulating dopaminergic phenotypic characters in pre-existing cells. The mechanism underlying this interesting phenotypic plasticity is unknown, but may be relevant to developing novel therapies for Parkinson's disease through stimulation of the brain's own potential for repair.
Animals ; Brain ; Bromodeoxyuridine ; Globus Pallidus ; Immunohistochemistry ; Neurons* ; Oxidopamine ; Parkinson Disease ; Plastics ; Rats* ; Stem Cells ; Substantia Nigra ; Tyrosine 3-Monooxygenase ; Tyrosine*