Ji Yong Jung

Gachon University, Seoul, Seoul, South Korea

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Publications (6)12.7 Total impact

  • Article: Study on the relationship between serum 25-hydroxyvitamin D levels and vascular calcification in hemodialysis patients with consideration of seasonal variation in vitamin D levels.
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    ABSTRACT: The aim of this study was to determine the prevalence of vitamin D deficiency in hemodialysis (HD) patients and the relationship between seasonal variations in vitamin D levels and vascular calcification. As a prospective observational study, we analyzed 289 HD patients. We have assessed serum 25-hydroxyvitamin D (25D) levels at the end of the summer (September) and winter (March) and analyzed the data to reveal the association of serum 25D level with vascular calcification scores (VCS) at the end of the summer, when vitamin D levels were found to peak. Plan X-ray images of lateral lumbar spine from all subjects were studied for calculation of semiquantitative VCS as described by Kauppila. The prevalence of 25D deficiency was 86.2% at the end of the summer and increased to 96.2% at the end of the winter. Female gender and diabetes were associated with vitamin D deficiency. According to univariate analysis, 25D levels were inversely related to vascular calcification. However, after correcting for confounding factors, this relationship lost statistical significance. Multivariate analysis showed that age, systolic blood pressure, and LDL-cholesterol levels were directly associated with a higher VCS. Vitamin D deficiency was highly prevalent in HD patients with marked seasonal variation. However, low 25D levels could not be identified as an independent predictor of vascular calcification in these patients.
    Atherosclerosis 11/2011; 220(2):563-8. · 3.79 Impact Factor
  • Article: Serum resistin as a novel marker of erythropoietin resistance in nondiabetic patients on hemodialysis
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    ABSTRACT: The use of higher erythropoietin (EPO) doses is associated with an increased risk of an adverse outcome and increased mortality in patients with renal failure. Resistin is related to heart disease, and may contribute to an increased atherosclerotic risk. We hypothesized that a link between resistin and EPO responsiveness may exist. We therefore investigated the relationship between resistin and the EPO resistance index (ERI) in nondiabetic hemodialysis (HD) patients. Fifty-seven patients enrolled in the study underwent HD for >/= 3 months and intravenous EPO therapy to maintain a target hemoglobin (Hb) level of 11.0 g/dl. The ERI was defined as the weekly EPO dose per unit Hb per body weight. The mean patient age was 52.6 +/- 11.9 years and the mean time on dialysis was 4.9 +/- 4.4 years. Serum Hb and ERI were 10.4 +/- 0.7 g/dl, and 13.3 +/- 7.0 (IU/kg/week/g/dl), respectively. Serum resistin levels were 23.6 +/- 9.3 microg/L. EPO resistance is associated with low body mass index (BMI) (coefficient beta =-0.393, p = 0.002) and with high serum resistin levels (coefficient beta = 0.332, p = 0.018). According to a multiple regression analysis, the serum resistin level was a significant independent factor related to EPO resistance (p = 0.017). The results suggest that serum resistin levels reflect EPO responsiveness in nondiabetic HD patients. Resistin may therefore be considered as a new marker of EPO responsiveness in HD patients.
    The Tohoku Journal of Experimental Medicine 07/2011; 224(4):281-285. · 1.24 Impact Factor
  • Article: Chronic kidney disease in cancer patients: an independent predictor of cancer-specific mortality
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    ABSTRACT: BACKGROUND/AIMS: The effects of chronic kidney disease (CKD) on the risk of death for patients with malignant disease are uncertain. The aim of this study was to determine the association between the presence of CKD and mortality in cancer patients. METHOD: We retrospectively reviewed the cases of 8,223 cancer patients with one or more serum creatinine measurements from January 1, 2000 to December 31, 2004. The key outcome was cancer-specific mortality within the follow-up period. The cumulative incidence rate for death from cancer was estimated using methods of competing risks survival analysis. Cox proportional-hazards regression with the use of Fine and Gray's proportional-hazards model were evaluated in multiple analyses. RESULTS: CKD was associated with an increased risk of death in cancer patients. The adjusted hazard ratios were 1.12 for patients with an estimated glomerular filtration rate (eGFR) of 30-59 ml/min/1.73 m(2) (95% confidence interval 1.01-1.26, p = 0.04) and 1.75 for patients with an eGFR <30 ml/min/1.73 m(2) (95% confidence interval 1.32-2.32, p < 0.001). CONCLUSIONS: CKD should be considered a risk factor for survival among patients with cancer.
    American Journal of Nephrology 01/2011; 33(2):121-130. · 2.54 Impact Factor
  • Article: High dose vitamin D3 attenuates the hypocalciuric effect of thiazide in hypercalciuric rats
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    ABSTRACT: Thiazide is known to decrease urinary calcium excretion. We hypothesized that thiazide shows different hypocalciuric effects depending on the stimuli causing hypercalciuria. The hypocalciuric effect of hydrochlorothiazide (HCTZ) and the expression of transient receptor potential vanilloid 5 (TRPV5), calbindin-D(28K), and several sodium transporters were assessed in hypercalciuric rats induced by high calcium diet and vitamin D(3). Urine calcium excretion and the expression of transporters were measured from 4 groups of Sprague-Dawley rats; control, HCTZ, high calcium-vitamin D, and high calcium-vitamin D with HCTZ groups. HCTZ decreased urinary calcium excretion by 51.4% in the HCTZ group and only 15% in the high calcium-vitamin D with HCTZ group. TRPV5 protein abundance was not changed by HCTZ in the high calcium-vitamin D with HCTZ group compared to the high calcium-vitamin D group. Protein abundance of NHE3, SGLT1, and NKCC2 decreased in the hypercalciuric rats, and only SGLT1 protein abundance was increased by HCTZ in the hypercalciuric rats. The hypocalciuric effect of HCTZ is attenuated in high calcium and vitamin D-induced hypercalciuric rats. This attenuation seems to have resulted from the lack of HCTZ's effect on protein abundance of TRPV5 in severe hypercalciuric condition induced by high calcium and vitamin D.
    Journal of Korean Medical Science 09/2010; 25(9):1305-1312. · 0.99 Impact Factor
  • Article: Serial testing of interferon-gamma-release assays for the diagnosis of latent tuberculosis in hemodialysis patients
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    ABSTRACT: INTRODUCTION: The performance of serial interferon-gamma-release assays (IGRAs) for the diagnosis of latent tuberculosis has not been studied in hemodialysis patients. METHOD: The QuantiFERON-TB-Gold In-Tube test (QFT) and T-SPOT-TB test (TSPOT) were performed 1 year after initial testing at a hemodialysis center. RESULTS: Ninety-eight patients were included in the final analysis. Positive rates for the initial tuberculin skin test (TST), QFT and TSPOT were 26.5%, 43.9% and 58.2%, respectively. The follow-up QFT and TSPOT showed positive responses in 52.0% and 53.1%. Conversion rates of the QFT and TSPOT were 20.0% and 26.8%. Reversion rates of the QFT and TSPOT were 16.3% and 29.8%; however, they decreased to 0.0% and 4.8% in patients with a concordantly positive response at the initial TST. A group at high risk for latent tuberculosis increased the risk for the TSPOT conversion [odds ratio (95% confidence interval), 7.76 (1.27-47.40)] and showed a trend of increasing the risk for the QFT conversion [1.97 (0.45-8.71)]. Reversion of both the QFT [18.92 (2.01-178.65)] and TSPOT [6.16 (1.57-24.19)] occurred more frequently in the group at low risk. CONCLUSIONS: Both conversion and reversion of the IGRAs were associated with the risk for latent tuberculosis in hemodialysis patients. However, serial IGRAs results should be interpreted cautiously due to their high variability.
    Journal of Infection 05/2010; 61(2):144-149. · 4.13 Impact Factor
  • Article: Altered regulation of renal sodium transporters in salt-sensitive hypertensive rats induced by uninephrectomy
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    ABSTRACT: Uninephrectomy (uNx) in young rats causes salt-sensitive hypertension (SSH). Alterations of sodium handling in residual nephrons may play a role in the pathogenesis. Therefore, we evaluated the adaptive alterations of renal sodium transporters according to salt intake in uNx-SSH rats. uNx or sham operations were performed in male Sprague-Dawley rats, and normal-salt diet was fed for 4 weeks. Four experimental groups were used: sham-operated rats raised on a high-salt diet for 2 weeks (CHH) or on a low-salt diet for 1 week after 1 week's high-salt diet (CHL) and uNx rats fed on the same diet (NHH, NHL) as the sham-operated rats were fed. Expression of major renal sodium transporters were determined by semiquantitative immunoblotting. Systolic blood pressure was increased in NHH and NHL groups, compared with CHH and CHL, respectively. Protein abundances of Na(+)/K(+)/2Cl(-) cotransporter (NKCC2) and Na(+)/Cl(-) cotransporter (NCC) in the CHH group were lower than the CHL group. Expression of epithelial sodium channel (ENaC)-gamma increased in the CHH group. In contrast, expressions of NKCC2 and NCC in the NHH group didn't show any significant alterations, compared to the NHL group. Expressions of ENaC-alpha and ENaC-beta in the NHH group were higher than the CHH group. Adaptive alterations of NKCC2 and NCC to changes of salt intake were different in the uNx group, and changes in ENaC-alpha and ENaC-beta were also different. These altered regulations of sodium transporters may be involved in the pathogenesis of SSH in the uNx rat model.
    Electrolyte & blood pressure: E & BP 12/2009; 7(2):58-66.