Heeyeon Cho

Complement regulation: physiology and disease relevance.

The complement system is part of the innate immune response and as such defends against invading pathogens, removes immune complexes and damaged self-cells, aids organ regeneration, confers neuroprotection, and engages with the adaptive immune response via T and B cells. Complement activation can either benefit or harm the host organism; thus, the complement system must maintain a balance between activation on foreign or modified self surfaces and inhibition on intact host cells. Complement regulators are essential for maintaining this balance and are classified as soluble regulators, such as factor H, and membrane-bound regulators. Defective complement regulators can damage the host cell and result in the accumulation of immunological debris. Moreover, defective regulators are associated with several autoimmune diseases such as atypical hemolytic uremic syndrome, dense deposit disease, age-related macular degeneration, and systemic lupus erythematosus. Therefore, understanding the molecular mechanisms by which the complement system is regulated is important for the development of novel therapies for complement-associated diseases.

Clinical Practice Guidelines for the Management of Atypical Hemolytic Uremic Syndrome in Korea

Atypical hemolytic uremic syndrome (aHUS) is a rare syndrome characterized by micro-angiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. The major pathogenesis of aHUS involves dysregulation of the complement system. Eculizumab, which blocks complement C5 activation, has recently been proven as an effective agent. Delayed diagnosis and treatment of aHUS can cause death or end-stage renal disease. Therefore, a diagnosis that differentiates aHUS from other forms of thrombotic microangiopathy is very important for appropriate management. These guidelines aim to offer recommendations for the diagnosis and treatment of patients with aHUS in Korea. The guidelines have largely been adopted from the current guidelines due to the lack of evidence concerning the Korean population.

Fluid overload and outcomes in neonates receiving continuous renal replacement therapy

BackgroundContinuous renal replacement therapy (CRRT) has emerged as the modality of choice for the management of high-risk neonates with acute kidney injury (AKI), inborn errors of metabolism and multi-organ dysfunction. The aim of this study was to evaluate fluid overload (FO) and investigate the factors associated with outcomes in neonates undergoing CRRT.MethodsWe retrospectively reviewed the medical records of 34 neonates with AKI who were admitted to the neonatal intensive care unit (NICU) of Samsung Medical Center, Seoul, Republic of Korea between January 2007 and December 2014 where they underwent at least 24 h of CRRT.ResultsThe survival rates of patients with an FO ofu2009≥30xa0% at the time of CRRT initiation were lower than those of patients with an FO ofu2009<30xa0% at the same time-point. Univariate Cox regression analysis revealed that a higher percentage FO at CRRT initiation and decreased urine output at the end of CRRT were associated with mortality, and multivariate Cox regression analysis indicated that mortality was associated with decreased urine output at the end of CRRT. Univariate linear regression analysis revealed that the length of hospital stay was associated with higher levels of serum creatinine at CRRT initiation, longer stay in the NICU prior to initiation of CRRT, longer duration of CRRT and lower body weight at the time of NICU admission.ConclusionsNeonates with a higher percentage FO and higher levels of serum creatinine at CRRT initiation showed poor outcomes. Early initiation of CRRT before the development of severe FO or azotemia might improve the outcomes of neonates requiring CRRT.

A compariosn of open and closed mobile platforms

The market of smartphone is growing at a remarkable rate and is one of the important emerging issues. People who use the smartphone go on increasing in the world. There are a lot of applications for the smartphone and they are more complicated. Therefore, various mobile platforms have been improved to meet such conditions. In this paper we consider desirable characteristics of open and closed mobile platforms for research. Based on these characteristics, we deal with two smartphone platforms: Android and iPhone.

Efficient path setup and recovery in wireless sensor networks by using the routing table

Interest for wireless sensor networks has being increased in ubiquitous environment. In wireless sensor networks, each node sets up self-organization network, transfer the sensing data to sink node. Sensor nodes that compose sensor network are small size, and their battery capacity is limited. So, each node also imposes a constraint on search and recovery of data-path. In this paper, we designed a method to build data-path, considering restrictive features of a sensor node. Each node uses the routing table which consists of state information of a node and neighbors, to set up the data-path. Using the routing table, they can efficiently transfer the sensing data from each node to a sink.

Influence of the Method of Definition on the Prevalence of Left-Ventricular Hypertrophy in Children with Chronic Kidney Disease: Data from the Know-Ped CKD Study

Background/Aims: Children with chronic kidney disease (CKD) have a high risk of cardiovascular disease. Left-ventricular (LV) hypertrophy (LVH) is an early marker of cardiovascular disease in pediatric CKD, and the prevalence of LVH in pediatric CKD is approximately 20-30% in pre-dialysis CKD patients. However, there is no consensus on the ideal method of defining LVH in pediatric CKD patients. Previous studies have typically used the LV mass index (LVMI), which is calculated as LV mass in grams divided by height in meters to the 2.7th power ≥ 38 g/m2.7, to diagnose LVH in children with CKD. Recently, age-specific reference values for LVMI ≥ 95th percentile and LV wall-thickness z-score > 1.64 in children were addressed. The aim of this study was to assess the prevalence and contributing factors of LVH in pediatric CKD patients according to each measurement and evaluate the concordance between each measurement. Methods: We used the baseline data of the KoreaN cohort study for Outcome in patients With Pediatric Chronic Kidney Disease (KNOW-Ped CKD), which is a nationwide, 10-year, prospective, observational cohort study of pediatric CKD. A total of 469 patients were enrolled, and 458 patients were included in the final analysis. Univariate and multiple logistic regression analysis were performed to evaluate the association of the variables with LVH. Kappa statistics were used to analyze the concordance. Results: According to an LVH diagnosis of LVMI ≥ 38 g/m2.7, 188 patients (41.0%) were diagnosed with LVH, and the prevalence of LVH was high in younger patients (< 2 years of age). Using the age-specific reference values, 116 patients (25.3%) were diagnosed with LVH, and there was no difference in the prevalence of LVH according to age. Thirty-one patients (6.8%) were diagnosed with LVH using an LV wall-thickness z-score > 1.64. There is poor concordance between the diagnosis of LVH using the LV wall-thickness z-score and the LVMI method. Conclusions: The results of this study show that there is poor concordance between the diagnosis of LVH using the wall-thickness z-score and the LVMI2.7 criteria. Further investigation is needed to estimate the correlation between LVH and cardiac dysfunction and to find a better method for defining LVH in the pediatric CKD cohort and thereby predicting cardiac dysfunction.

Metabolic features and renal outcomes of urolithiasis in children

Abstract Aim: The incidence of pediatric urolithiasis has increased over the last century because of dietary changes, metabolic abnormalities, climate change, and genitourinary abnormalities. Data on pediatric urolithiasis in non-endemic countries are limited. The aim of this study was to evaluate the clinical findings and metabolic etiology of urolithiasis in Korean children. Material and methods: The medical records of 73 Korean children who were newly diagnosed with urolithiasis from January 2010 to December 2013 were retrospectively analyzed. Evaluation of metabolic risk factors, including hypercalciuria, hyperuricosuria, hypomagnesuria, hyperoxaluria, and hypocitraturia, required analysis of 24-h urine specimens or, alternatively, for infants and toddlers, the solute-creatinine ratio in spot urine. Results: The male-to-female ratio of the included patients was 1.3:1. The median age at diagnosis was 10.1 years, and the patients were divided into two age groups with pre-school-age children (nu2009=u200927, 37.0%) and school-age children (nu2009=u200946, 63.0%). While flank pain was more common in school-age children, incidentally detected or urinary tract infection (UTI)-associated urolithiasis was more common in pre-school-age children. Eight patients (11.0%) had renal function deterioration associated with urolithiasis, and three patients (4.1%) progressed to chronic kidney disease. Metabolic abnormalities according to urine chemistry were found in 30 patients (41.1%), including hypercalciuria in 21.9%, hyperuricosuria in 11.0%, hypomagnesuria in 4.1%, hyperoxaluria in 1.4%, hypocitraturia in 1.4%, and cystinuria in 1.4%. Conclusion: We suggest that school-age children with renal colic and pre-school-age children with UTI should be evaluated for urolithiasis. Additionally, the evaluation for metabolic risk factors is important in order to prevent recurrence and renal insufficiency.

Publication of the Korea-WHO Cooperation History — 70 Years of Working Together for Heath: World Health Organization and the Republic of Korea

The World Health Organization (WHO) have been in collaborative efforts with the Republic of Korea in keeping of and for better health for all for the past decades. From the control of parasites to building of community health system in rural places, the works has now resulted in healthier Korea than ever, and has transformed the role of engaging as the world leader in contribution of health and development. Seventy years of independence, war, and poverty, transforming from a recipient country of official development assistance to a significant donor to the global society, we have emphasized the importance of international cooperation and the role of WHO in the past years in Korea and neighboring countries. Looking back of the past is meaningful to diagnose the present problems, and to foresee the future of our world.

Favorable long-term outcomes of isolated liver transplantation in a child with atypical hemolytic uremic syndrome caused by a novel complement factor H mutation

Atypical hemolytic uremic syndrome (aHUS) is a rare syndrome characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury that is usually caused by complement dysregulation. Complement factor H (CFH) is a regulator of the complement system produced in the liver, and CFH gene mutations are the most frequent causes of aHUS. To date, the therapeutic options for aHUS with CFH mutations have consisted of plasma infusions, plasma exchange, kidney transplantation, isolated liver transplantation, or combined liver and kidney transplantation. Recently, eculizumab, a humanized monoclonal antibody directed against complement C5, has been proven to be effective against aHUS. However, life-long eculizumab maintenance therapy is usually required for aHUS; therefore, other curative options should be considered. We describe a case of neonatal onset aHUS caused by a novel mutation of CFH and treated with an isolated liver transplantation at the age of 24 months. Nearly 5 years post-transplant, the patients health has been generally good without evidence of aHUS. This case report suggests that isolated liver transplantation in aHUS patients with CFH mutations and preserved eGFR could be a curative therapeutic option in contrast to long-term eculizumab therapy.u2029.

Posterior reversible encephalopathy syndrome caused by presumed Takayasu arteritis

Takayasu arteritis (TA) is a chronic inflammatory disease of unknown etiology that affects mainly the aorta, main aortic branches, and pulmonary arteries. Diverse neurological manifestations of TA have rarely been reported in children. Posterior reversible encephalopathy syndrome (PRES) is a neuroradiological condition that presents with headache, seizure, visual disturbances, and characteristic lesions on imaging. Inflammatory condition and severe hypertension in TA can cause PRES. We report of a 5-year-old girl with presumed TA who presented with PRES and chronic total occlusion in the renal artery. The findings on magnetic resonance imaging suggested PRES. Left nephrectomy was performed for total occlusion of the left renal artery, and the confirmatory diagnosis of TA was based on the pathologic findings of the renal artery.