Yong-Hoon Park

Yeungnam University, Asan, South Chungcheong, South Korea

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Publications (17)27.95 Total impact

  • Article: Clinical characteristics of Kawasaki disease with sterile pyuria.
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    ABSTRACT: Kawasaki disease (KD) is a systemic vasculitis and affects many organ systems. It often presents sterile pyuria, microscopic hematuria, and proteinuria due to renal involvement. The aims of this study were to define clinical characteristics of acute KD patients with pyuria and to analyze meaning of pyuria in KD. The medical records and laboratory findings including serum and urine test of 133 patients with KD admitted to Yeungnam University Hospital from March 2006 to December 2010 were reviewed retrospectively. Forty patients had sterile pyuria and their clinical characteristics including age, gender and body weight were not significantly different with those who did not have pyuria. Fever duration after treatment was significantly longer in KD patients with pyuria. Erythrocyte sedimentation rate, C-reactive protein and serum concentration of alanine aminotransferase were significantly higher in patients with pyuria. Hyponatremia and coronary artery lesion were seen more often in patients with pyuria but there was no significant difference. Also serum blood urea nitrogen was significantly higher in KD patients with pyuria. Urine β(2)-microglobulin was elevated in both patients groups and showed no difference between two groups. We found more severe inflammatory reaction in KD patients with pyuria. We also found elevation of some useful parameters like β(2)-microglobulin that indicate renal involvement of KD through the urine test. Careful management and follow up will need for KD patients with pyuria and it is necessary in the future to study the specific parameters for renal involvement of KD.
    Korean Journal of Pediatrics 01/2013; 56(1):13-8.
  • Article: Dense deposit disease in korean children: a multicenter clinicopathologic study.
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    ABSTRACT: The purpose of this study was to investigate the clinical, laboratory, and pathologic characteristics of dense deposit disease (DDD) in Korean children and to determine whether these characteristics differ between Korean and American children with DDD. In 2010, we sent a structured protocol about DDD to pediatric nephrologists throughout Korea. The data collected were compared with previously published data on 14 American children with DDD. Korean children had lower 24-hr urine protein excretion and higher serum albumin levels than American children. The light microscopic findings revealed that a higher percentage of Korean children had membranoproliferative glomerulonephritis patterns (Korean, 77.8%; American, 28.6%, P = 0.036), whereas a higher percentage of American children had crescents (Korean, 0%; American, 78.6%, P < 0.001). The findings from the electron microscopy revealed that Korean children were more likely to have segmental electron dense deposits in the lamina densa of the glomerular basement membrane (Korean, 100%; American, 28.6%, P = 0.002); mesangial deposit was more frequent in American children (Korean, 66.7%; American, 100%, P = 0.047). The histological findings revealed that Korean children with DDD were more likely to show membranoproliferative glomerulonephritis patterns than American children. The degree of proteinuria and hypoalbuminemia was milder in Korean children than American children.
    Journal of Korean medical science 10/2012; 27(10):1215-21. · 0.84 Impact Factor
  • Article: Significance of electron dense deposits in patients with minimal change nephrotic syndrome.
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    ABSTRACT: Minimal change nephritic syndrome (MCNS) is characterized by a lack of obvious abnormalities on light microscopy, but its electron microscopic findings include the negative immunofluorescence findings and the diffuse effacement of the epithelial cell foot processes. Rarely the presence of electron dense deposits (EDDs) has been reported, but its clinical significance remains obscure. Eleven patients with MCNS who had the EDD deposited were enrolled in the current study. We compared the clinical characteristics, laboratory results and response to steroid treatment between the two group: the EDD group (n=11; the male-to-female ratio, 8:3) and the non-EDD group (n=13, 8:5). There were no significant differences in most of the laboratory results or response to steroid treatment between the two groups. The frequency of relapses per year was significantly higher in the EDD group (1.1±0.7 times vs. 0.5±0.6 times; p=0.023). These EDDs were found in the mesangium or paramesangium. With no respect to the characteristics of EDDs, our results showed that they did not cause poor treatment outcomes except for the annual frequency of relapse. Further large-scale studies are warrented to determine the immunologic and prognostic significance of EDDs in patients with MCNS.
    Korean journal of pathology. 04/2012; 46(2):137-41.
  • Article: Management of Urinary Tract Infections in Children: A Survey of Pediatricians in Daegu City
    J Korean Soc Pediatr Nephrol. 01/2012; 16(2):95.
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    Article: A case of tacrolimus-induced encephalopathy after kidney transplantation.
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    ABSTRACT: We present a case of tacrolimus-induced encephalopathy after successful kidney transplantation. An 11-year-old girl presented with sudden onset of neurologic symptoms, hypertension, and psychiatric symptoms, with normal kidney function, after kidney transplantation. The symptoms improved after cessation of tacrolimus. Magnetic resonance imaging (MRI) showed acute infarction of the middle cerebral artery (MCA) territory in the right frontal lobe. Three days later, she had normal mental function and maintained normal blood pressure with left hemiparesis. Follow-up MRI was performed on D19, showing new infarct lesions at both cerebral hemispheres. Ten days later, MRI showed further improvement, but brain single photon emission computed tomography (SPECT) showed mild reduction of uptake in both the anterior cingulate gyrus and the left thalamus. One month after onset of symptoms, angiography showed complete resolution of stenosis. However, presenting as a mild fine motor disability of both hands and mild dysarthria, what had been atrophy at both centrum semiovale at 4 months now showed progression to encephalomalacia. There are two points of interest in this case. First, encephalopathy occurred after administration of tacrolimus and improved after discontinuation of the drug. Second, the development of right-side hemiplegia could not be explained by conventional MRI; but through diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) of white matter tract, visualization was possible.
    Korean Journal of Pediatrics 01/2011; 54(1):40-4.
  • Article: A case of steroid-induced psychosis in a child having nephrotic syndrome with toxic epidermal necrolysis
    Sae Yoon Kim, Jae Min Lee, Yong Hoon Park
    Korean Journal of Pediatrics 01/2010; 53(3):437-441.
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    Article: Clinico-genetic study of nail-patella syndrome.
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    ABSTRACT: Nail-patella syndrome (NPS) is an autosomal dominant disease that typically involves the nails, knees, elbows and the presence of iliac horns. In addition, some patients develop glomerulopathy or adult-onset glaucoma. NPS is caused by loss-of-function mutations in the LMX1B gene. In this study, phenotype-genotype correlation was analyzed in 9 unrelated Korean children with NPS and their affected family members. The probands included 5 boy and 4 girls who were confirmed to have NPS, as well as 6 of their affected parents. All of the patients (100%) had dysplastic nails, while 13 patients (86.7%) had patellar anomalies, 8 (53.3%) had iliac horns, 6 (40.0%) had elbow contracture, and 4 (26.7%) had nephropathy including one patient who developed end-stage renal disease at age 4.2. The genetic study revealed 8 different LMX1B mutations (5 missense mutations, 1 frame-shifting deletion and 2 abnormal splicing mutations), 6 of which were novel. Genotype-phenotype correlation was not identified, but inter- and intrafamilial phenotypic variability was observed. Overall, these findings are similar to the results of previously conducted studies, and the mechanism underlying the phenotypic variations and predisposing factors of the development and progression of nephropathy in NPS patients are still unknown.
    Journal of Korean Medical Science 02/2009; 24 Suppl:S82-6. · 0.99 Impact Factor
  • Article: Prevalence and associated factors of overactive bladder in Korean children 5-13 years old: a nationwide multicenter study.
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    ABSTRACT: To estimate the prevalence of overactive bladder (OAB) in Korean children, 5-13 years of age, and to assess the associated factors for OAB. A randomly selected cross-section study was conducted in 26 kindergartens and 27 elementary schools nationwide in Korea. A total of 19 240 children were included; a parent was asked to complete the questionnaires, which included items about OAB and voiding and defecating habits. OAB was defined as urgency with or without urge incontinence, usually with increased daytime frequency and nocturia (International Children's Continence Society, 2006). Its prevalence and associated factors were also investigated. The response rate for the questionnaires was 85.84%. The overall prevalence of OAB was 16.59%. The prevalence of OAB decreased with age from 22.99% to 12.16% (P = .0001). The overall incidence of wet and dry OAB was 26.97% and 73.03%, respectively. Compared with normal children, those with OAB had a greater prevalence of nocturnal enuresis, constipation, fecal incontinence, urinary tract infection, delayed bladder control, and poor toilet facilities (P < .05). The incidence of increased daytime frequency and urge incontinence was 3.69% and 2.31% (P = .009) and 26.97% and 14.78% (P = .0001) in OAB and non-OAB children, respectively. The corresponding prevalence decreased with age from 5.04% to 3.06% and from 45.74% to 18.50% in OAB children (P = .0001). The overall prevalence of OAB in Korean children, 5-13 years of age, was 16.59% and decreased with age. Nocturnal enuresis, constipation, fecal incontinence, history of urinary tract infection, delayed bladder control, and poor toilet facilities might be factors associated with the development of OAB.
    Urology 10/2008; 73(1):63-7; discussion 68-9. · 2.43 Impact Factor
  • Article: Simultaneous analysis of d-3-methoxy-17-methylmorphinan and l-3-methoxy-17-methylmorphinan by high pressure liquid chromatography equipped with PDA.
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    ABSTRACT: d-3-Methoxy-17-methylmorphinan (Dextromethorphan, DXM), which is a structural analog of morphine and codeine, has been widely used as a non-narcotic antitussive agent. It is a safe drug in therapeutic dose and does not produce analgesic effects, while its enantiomer, l-3-methoxy-17-methylmorphinan called levomethorphan (LXM) is a potent narcotic analgesic. DXM has been widely abused in Korea due to its hallucinogenic effect in large doses; therefore, the health authorities have regulated its use as a psychotropic agent since 2003. As its abuse has been serious, a possibility that DXM would be smuggled into Korea has also increased. Moreover, it has been suspected that there was the possibility of the adulteration or substitution of DXM with LXM due to their chemical similarities. Therefore, it was necessary for us to establish the enantiomeric separation of DXM and LXM. In this study, a liquid chromatographic method using a chiral column capable of separating stereoisomers of DXM as well as analyzing the major metabolites of DXM, 3-methoxymorphinan, 3-hydroxymorphinan, and 17-hydroxymethylmorphinan was developed. The validation of a method was studied through repeatability of retention times. Using this method, 32 confiscated DXM samples were analyzed to identify the enantiomers of DXM. As a result, DXM was detected in all samples and there was no evidence of the adulteration or substitution of DXM with LXM. Nevertheless, the stereochemical analysis of DXM and LXM is important not only to identify starting materials for illegal drug manufacture but also to understand the trends of abused drugs.
    Forensic Science International 10/2006; 161(2-3):185-8. · 2.30 Impact Factor
  • Article: Metformin restores leptin sensitivity in high-fat-fed obese rats with leptin resistance.
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    ABSTRACT: To evaluate whether metformin enhances leptin sensitivity, we measured leptin sensitivity after 4 weeks of metformin treatment (300 mg/kg daily) in both standard chow and high-fat-fed obese rats. Anorexic and fat-losing responses after intracerebroventricular leptin infusion for 7 days (15 microg daily per rat) in standard chow rats were enhanced by metformin treatment, and these responses to leptin were attenuated in high-fat-fed obese rats compared with age-matched standard chow rats. However, these responses to leptin were corrected by metformin treatment in high-fat-fed obese rats. Moreover, serum concentrations of leptin and insulin were decreased dramatically by leptin in metformin-treated standard chow and high-fat-fed obese rats. The hypothalamic phosphorylated AMP-activated protein kinase level was decreased by lower leptin dose in metformin-treated rats than in untreated rats. In an acute study, metformin treatment also increased the anorexic effect of leptin (5 microg), and this was accompanied by an increased level of phosphorylated signal transducer and activator of transcription 3 in the hypothalamus. These results suggest that metformin enhances leptin sensitivity and corrects leptin resistance in high-fat-fed obese rats and that a combination therapy including metformin and leptin would be helpful in the treatment of obesity.
    Diabetes 04/2006; 55(3):716-24. · 8.29 Impact Factor
  • Article: Hematuria and proteinuria in a mass school urine screening test.
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    ABSTRACT: A total of 1,044 school children identified with hematuria and/or proteinuria during a mass school urine screening test were referred to pediatric nephrologists at 13 hospitals in Korea. These children had isolated hematuria (IH) (60.1%), isolated proteinuria (IP) (26.4%: transient, 19.6%; orthostatic, 4.9%; persistent, 1.9%) or combined hematuria and proteinuria (CHP) (13.5%). The patient's history, physical examination, laboratory tests, kidney ultrasound and Doppler ultrasonography were obtained. Renal biopsies were performed on 113 children who showed severe proteinuria, hypertension, abnormal renal function, family history of chronic renal disease, systemic diseases or persistent hematuria and/or proteinuria for more than 12 months. IgA nephropathy (IgAN), thin basement membrane nephropathy (TBMN), membranoproliferative glomerulonephritis (MPGN), focal segmental glomerulosclerosis (FSGS), other GN, Alport syndrome and lupus nephritis were detected. IgAN and TBMN were the most common causes in the CHP group and IH group, respectively. Abnormal findings on the renal ultrasound with or without Doppler ultrasonography were noted in 147 cases (suspected nutcracker phenomenon, 65; increased parenchymal echogenicity, 40; hydronephrosis, 15). This study showed that the use of a mass school urine screening program can detect chronic renal disease in its early stage and recommends that more attention should be paid to identifying those children with CHP and massive proteinuria. A school urine screening program can detect chronic renal disease in its early stage. When mass screening is used, the initial aggressive diagnostic procedures such as renal biopsy are not needed. In addition, a regular follow-up for those children with IH and IP is certainly warranted.
    Pediatric Nephrology 09/2005; 20(8):1126-30. · 2.52 Impact Factor
  • Article: Leptin-like effects of MTII are augmented in MSG-obese rats.
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    ABSTRACT: To evaluate whether MTII, a melanocortin receptor 3/4 agonist, is working in hypophagic and hypothermogenic obese model, we measured food intake, body weight, oxygen consumption, and fat mass following intracerebroventricular (i.c.v.) infusion of MTII in monosodium glutamate (MSG)-induced obese rats. MTII, or artificial cerebrospinal fluid (aCSF), was infused into i.c.v. with an osmotic minipump for 1 week. MSG-obese rats were induced by neonatal injection of MSG. Five-month-old MSG rats were characterized by hypophagia, lower oxygen consumption, hyperleptinemia, and obesity compared to age-matched control rats. The infusion of MTII decreased their food intake, visceral fat, and body weight in MSG-obese rats compared with aCSF-infused rats. The oxygen consumption was increased by MTII treatment in MSG-obese rats compared with aCSF as well as pair fed (PF) rats. Interestingly, these leptin-like effects of MTII were greater in MSG-obese rats than in controls, which might be related to the increased expression of melanocortin receptor 4 (MC4R) in the hypothalamus of MSG-obese rats. Our results suggested that both anorexic and thermogenic mechanisms were activated by MTII in the MSG-obese rats and contributed to the decrease in body weight and fat mass. Moreover, there was a sensitization to MTII caused by upregulation of the melanocortin receptor in the MSG-obese rats.
    Regulatory Peptides 05/2005; 127(1-3):63-70. · 2.11 Impact Factor
  • Article: A case of complicated spastic paraplegia 2 due to a point mutation in the proteolipid protein 1 gene.
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    ABSTRACT: Pelizaeus-Merzbacher disease (PMD) is a rare X-linked dysmyelinating disorder resulting from mutation of the proteolipid protein gene (PLP1). Clinical features of PMD include progressive psychomotor developmental delay, nystagmus, spastic quadriplegia, dystonia, and cerebellar ataxia. PMD is clinically classified into three subtypes according to the severity of the disease: connatal, transitional, and classic forms. Patients with PMD have been identified with duplication, point mutations, and deletion of PLP1. In addition, spastic paraplegia 2 (SPG2) is allelic to PMD and typically caused by missense mutations in the second extracellular domain of PLP1 or in the PLP1-specific region that is spliced out during formation of the DM20 isoform. The authors describe a Korean boy diagnosed with SPG2 caused by a mutation that results in a Pro215Leu substitution in the second extracellular domain. Analysis of phenotypes resulting from mutations affecting PLP1 has been valuable in identifying functional domains of this still incompletely understood major myelin protein. Null mutations and mutations affecting the PLP1-specific domain cause peripheral neuropathy. The PLP1-specific domain also is important in the long-term maintenance of axonal integrity. This patient's phenotype was relatively mild, in contrast with other mutations at position 215 of PLP1 that cause severe PMD. One of these severe mutations is also a missense mutation substituting an aliphatic residue, alanine, for proline. The distinct severity difference between the Pro215Leu and Pro215Ala substitutions suggests that this region of the protein is very sensitive to subtle structural changes and likely plays a critical role in PLP1 function.
    Journal of the Neurological Sciences 10/2004; 224(1-2):83-7. · 2.35 Impact Factor
  • Article: Potentiated modulation of pregnolone on GABAA receptors in behaviorally stressed borderline-hypertensive rats.
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    ABSTRACT: The modulatory effects of behavioral stress on [(3)H]flunitrazepam, an agonist for the central-type benzodiazepine receptor binding to the GABA(A)-benzodiazepine receptor complex, in borderline hypertensive rats (BHR) were examined. In repeatedly immobilized (for 2 weeks, for 2 h/d) BHR, enhancement of [(3)H]flunitrazepam binding to the receptor was observed to be potentiated. The percent enhancement of [(3)H]flunitrazepam binding in BHR was higher than that in normotensive control Wistar-Kyoto rats. Pregnanolone, a neuroactive steroid that has been reported to be a putative endogenous modulator in the stress response, concentration dependently enhanced [(3)H]flunitrazepam binding to the receptor. Enhancement of [(3)H]flunitrazepam binding was observed to be potentiated by the same immobilized stress, and the EC(50) values of pregnanolone in BHR was significantly lower than those in controls and E(max) values were higher. From the above results, it can be concluded that neural modulation to behavioral stress, especially in GABAergic neurotransmission, is exaggerated in BHR. We propose strain-specific differences of stress reactivity as an important pathogenetic factor in psychosomatic disorders including stress-induced hypertension. This is supported by reports showing exaggerated cardiovascular and symathoadrenal responses to stress in BHR.
    Biological & Pharmaceutical Bulletin 02/2004; 27(1):122-4. · 1.66 Impact Factor
  • Article: Aging-associated increase of gelsolin for apoptosis resistance.
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    ABSTRACT: Gelsolin, a Ca(2+)-dependent actin regulatory protein, was recently suggested to participate in apoptosis regulation. In this study, we found that the level of gelsolin is elevated in senescent human diploid fibroblasts (HDFs) and also in the tissues of old rats, i.e., in the liver, kidney, heart, spleen, stomach, and brain, etc. The ubiquitous increase of gelsolin in the aged organs and cells led us to assume that it might be related with one of the cardinal senescent phenotypes, aging-associated apoptosis resistency. Thus, we tested the sensitivity of senescent cells to apoptosis by menadione, an apoptosis-inducing agent, before and after the down-regulation of gelsolin. The down-regulation of gelsolin in senescent HDFs, independently of Bcl-2 family expression, resulted in an increased sensitivity to menadione-induced apoptotic cell death. The observed ubiquitous increase of gelsolin in the senescent states of cells and tissues, and the increased sensitivity to apoptosis-induction by gelsolin down-regulation, suggests that gelsolin would be partly responsible for age-related apoptosis resistance.
    Biochemical and Biophysical Research Communications 01/2004; 312(4):1335-41. · 2.48 Impact Factor
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    Article: Pirfenidone suppressed the development of glomerulosclerosis in the FGS/Kist mouse.
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    ABSTRACT: Pirfenidone (PFD) is a newly developed anti-fibrotic agent. We evaluated the effect of PFD for the prevention of renal fibrosis using a spontaneous progressive glomerulosclerosis animal model, FGS/Kist mice. Male and female FGS/Kist mice were fed a diet containing 0.5% PFD or the same control diet (CD) without PFD, for 1, 2, or 3-month periods. Body weight was monitored for the general effect of PFD on the mice. Proteinuria and glomerular filtration rate (GFR) were evaluated for renal function. The sclerosis index was examined for the morphological changes. There were no significant changes in body weight between the PFD and control groups in both sexes. Proteinuria levels were low in all the PFD groups compared to the corresponding CD groups. The sclerosis scores were also reduced in both sexes of the 3-month PFD groups (p<0.05), and glomerular filtration rates were increased in both sexes of the 3-month PFD groups compared to the CD groups. The treatment of PFD for 1 or 2-month periods did not have statistic significances but the treatment for 3 months had statistic significances in sclerosis and GFR compared to CD groups. These results suggested that long-term administration of PFD suppressed the progression of glomerulosclerosis and improved renal function of the FGS/Kist mice.
    Journal of Korean Medical Science 08/2003; 18(4):527-33. · 0.99 Impact Factor
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    Article: Effects of thyroxine on hyperkalemia and renal cortical Na+, K+ - ATPase activity induced by cyclosporin A.
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    ABSTRACT: Cyclosporin A (CsA)-induced hyperkalemia is caused by alterations in transepithelial K+ secretion resulting from the inhibition of renal tubular Na+, K+ -ATPase activity. Thyroxine enhances renal cortical Na+, K+ -ATPase activity. This study investigated the effect of thyroxine on CsA-induced hyperkalemia. Sprague-Dawley rats were treated with either CsA, thyroxine, CsA and thyroxine, or olive-oil vehicle. CsA resulted in an increase in BUN and serum K+, along with a decrease in creatinine clearance, fractional excretion of potassium, and renal cortical Na+, K+ -ATPase activity, as compared with oil vehicle administration. Histochemical study showed reduced Na+, K+ -ATPase activity in the proximal tubular epithelial cells of the CsA-treated compared with the oil-treated rats. Histologically, isometric intracytoplasmic vacuolation, disruption of the arrangement and swelling of the mitochondria, and a large number of lysosomes in the tubular epithelium were characteristic of the CsA-treated rats. Co-administration of thyroxine prevented CsA-induced hyperkalemia and reduced creatinine clearance, Na+, K+ -ATPase activity, and severity of the histologic changes in the renal tubular cells when compared with the CsA-treated rats. Thyroxine increased the fractional excretion of potassium via the preservation of Na+, K+ -ATPase activity in the renal tubular cells. Thus, the beneficial effects of thyroxine may be suited to treatment modalities for CsA-induced hyperkalemia.
    Journal of Korean Medical Science 11/2002; 17(5):625-32. · 0.99 Impact Factor