J.K. Hwang

Catholic University of Korea, Sŏul, Seoul, South Korea

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Publications (30)50.18 Total impact

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    ABSTRACT: Our objective was to compare the clinical outcomes of adult kidney transplants from expanded criteria deceased donors (ECD) with those from concurrent standard criteria deceased donors (SCD). Between January 2000 and December 2011, we transplanted 195 deceased donor renal transplants into adult recipients, including 31 grafts (15.9%) from ECDs and 164 grafts (84.1%) from SCDs. ECDs were classified using the United Network for Organ Sharing (UNOS) definitions. Donor and recipient risk factors were analyzed separately and their correlation with recipient graft function and survival was evaluated (minimum 6-month follow-up). ECDs were older (56.8 ± 6.3 years), showed an increased incidence of hypertension, diabetes, and cerebrovascular brain death, and had a higher preretrieval serum creatinine level than SCDs. ECD kidney recipients had a shorter waiting time (P = .019) but other baseline characteristics (age, gender, body mass index [BMI], cause of end-stage renal disease, type of renal replacement therapy, incidence of diabetes and hypertension, number of HLA antigen mismatches, positivity for panel-reactive antigen, and cold ischemic time) were not significantly different from those of SCD kidney recipients. Mean glomerular filtration rate (GFR) at 1 month, 6 months, 1 year, and 3 years after transplantation was significantly lower in recipients of ECD transplants than recipients of SCD transplants, but the GFR level at 5 and 10 years was not significantly different between ECD and SCD recipient groups (P = .134 and .702, respectively). Incidence of acute rejection episodes and surgical complications did not differ significantly between the 2 recipient groups, but the incidence of delayed graft function (DGF) and infectious complications was higher in ECD kidney recipients than SCD kidney recipients (P = .007 and P = .008, respectively). Actual patient and graft survival rates were similar between the 2 recipient groups with a mean follow-up of 43 months. There were no significant differences in graft survival (P = .111) or patient survival (P = .562) between the 2 groups. Although intermediate-term renal function followed longitudinally was better in SCD kidney recipients, graft and patient survival of ECD kidney recipients were comparable with those of SCD kidney recipients. In conclusion, use of renal grafts from ECDs is a feasible approach to address the critical organ shortage.
    No preview · Article · Mar 2014 · Transplantation Proceedings
  • M.H. Kim · K.M. Park · J.K. Hwang · S.C. Park · I.S. Moon · J.I. Kim
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    ABSTRACT: The purpose of this study was to determine the natural history of arteriovenous (AV) access after successful kidney transplantation (KT) and to identify the risk factors of spontaneous access closure in kidney transplant recipients. We performed a retrospective review of 115 patients who underwent KT with functioning access from June 2010 to July 2012. AV access patency was checked and recorded daily during the hospital stay and at every visit to the outpatient clinic. Patients were divided into 2 groups according to the patency of access, and risk factors of access thrombosis were assessed. Access patency was followed up until patency was lost or the study was closed. At the end of follow-up, 18 (15.7%) AV accesses had spontaneously closed. Mean time to closure was 119 ± 163 days, and 12 of 18 were closed within 90 days after KT. AV access spontaneously closed in 8.5% of male patients, compared with 27.3% of female patients (P = .007), 12.2% of cases with native access compared with 35.3% of cases with artificial access (P = .016), and 11.3% of cases with wrist access compared with 25.7% of cases with elbow access (P = .049). Spontaneously closed AV accesses tended to have a lower mean access flow compared with functioning accesses (P = .019). On multivariate analysis, female sex and AV access flow volume affected spontaneous AV access closure (odds ratio 4.749, 95% confidence interval 1.919-35.383, P = .008; odds ratio 0.998, 95% confidence interval 0.996-0.999, P = .010, respectively). Our results suggest that AV access thrombosis occurs more frequently during the early postoperative period, particularly in female patients or patients with low flow access, whereas it is a rare event in male patients or patients with high access flow, especially in the late postoperative period.
    No preview · Article · Mar 2014 · Transplantation Proceedings
  • J.K. Hwang · J.M. Kim · Y.K. Kim · S.D. Kim · S.C. Park · J.I. Kim · H.W. Nam · J.M. Kim · I.S. Moon
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    ABSTRACT: Heat shock proteins (HSP) play an important role in protecting cells against stress. Using a rat model, we tested the hypothesis that pretreatment with glutamine (Gln) and ischemia preconditioning (IPC) increase the expression of HSP resulting in attenuation of renal ischemia/reperfusion (I/R) injury. Sprague-Dawley rats were randomized into 4 groups [group I, Gln injection (+), IPC (+); group II, Gln injection (+), IPC (-); group III, saline injection (+), IPC (+); group IV, saline injection (+), IPC (-)]. Renal HSP70 expression was determined by Western blotting and kidney function was assessed by blood urea nitrogen and serum creatinine. Renal cross-sections were microscopically examined for tubular necrosis, exfoliation of tubular epithelial cells, cast formation, and monocyte infiltration. Gln pretreatment increased intrarenal HSP expression (P = .031). In group I, tubulointerstitial abnormalities were clearly slighter compared with the other groups (P < .001). Our experiments suggest that (1) a single dose of Gln could induce HSP expression and (2) IPC could relieve renal I/R injury. In addition, IPC combined with Gln pretreatment had a synergic protective effect against renal I/R injury.
    No preview · Article · Nov 2013 · Transplantation Proceedings
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    ABSTRACT: Our objective was to evaluate the usefulness of three-dimensional (3-D) contrast-enhanced (CE) magnetic resonance angiography (MRA) to assess renal parenchyma, arterial inflow stenosis, and peritransplant fluid collections in the early period after kidney transplantation (KT). Between January 2010 and April 2011, we examined a consecutive series of 144 renal transplants using 3-D CE MRA at 14 days after KT. MRA showed parenchyma infarctions (n = 17, 11.8%), arterial inflow stenoses (n = 23, 16%), lymphoceles (n = 14, 9.7%), and hematomas (n = 6, 4.2%). The degree of renal transplant artery inflow stenosis was graded qualitatively based on diameter criterion; <50% = mild, 50% to 70% = moderate, and >70% = severe in 10 (6.9%), 5 (3.5%), and 8 (5.6%) subjects, respectively. The study recipients were divided into 3 groups according to the degree of renal artery inflow stenosis (group I: normal; group II: mild and moderate, <70%; group III: severe, >70%). Among group III patients who underwent digital subtraction angiography, 5 had percutaneous transluminal angioplasty or stenting performed after 1 month. Their mean resume creatinine levels at 1, 6, and 12 months after transplantation were not significantly different from those in the other groups (P = .391, .447, .110). The prevalence of graft loss (n = 2) was high in group III (P = .012), although the frequency of acute rejection episodes was not different among the groups (P = .890). The incidences of renal parenchyma infarction, peritransplant fluid collection and arterial inflow stenosis were unexpectedly high in the early period after KT. Thus, 3-D CE MRA provided a rapid global assessment of the renal parenchyma, transplant arterial system, and peritransplant fluid collection that can be helpful to detect or exclude many causes of renal transplant dysfunction.
    No preview · Article · Oct 2013 · Transplantation Proceedings
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    M.R. Lee · G.W. Nam · Y.C. Jung · S.Y. Park · J.Y. Han · J.C. Cho · K.D. Suh · J.K. Hwang
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    ABSTRACT: Background  Regional and ethnic (racial) differences in skin properties are well known. However, regional and racial studies are limited and have studied skin properties using an insufficient number of subjects and limited ethnic groups, except in the case of some recent studies. Objective  The aim of this study was (1) to compare the skin biophysical parameter among the large scale of Southeast Asia females group and (2) to compare skin properties of the forehead and cheek. Methods  We measured and compared seven skin biophysical parameters, such as skin hydration, sebum, skin pH, melanin index, erythema index, skin elasticity and transepidermal water loss (TEWL), of the forehead and cheek of a large population of Indonesian (n = 200), Vietnamese (n = 100) and Singaporean females (n = 97). Results  At the point of site difference, there were significant differences in five biophysical parameters (skin hydration, skin pH, melanin index, erythema index and skin elasticity) in Indonesian females. In Vietnamese and Singaporean women, they were significant differences in five biophysical parameters (skin hydration, skin pH, melanin index, erythema index and TEWL). At the point of ethnic difference, the Indonesian women had the highest skin pH and melanin index between the different ethnic groups. Vietnamese women had the highest skin hydration and TEWL in the forehead, whereas Singaporean women had the highest skin elasticity. Conclusion  The skin biophysical parameters are different between the forehead and cheek among Southeast Asian females. It also reveals that the biophysical parameters are different in same racial group.
    Full-text · Article · Dec 2012 · Journal of the European Academy of Dermatology and Venereology

  • No preview · Article · Nov 2012 · Transplantation

  • No preview · Article · Nov 2012 · Transplantation

  • No preview · Article · Nov 2012 · Transplantation
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    Full-text · Article · Mar 2012
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    ABSTRACT: This study evaluated the effect of the donor kidney to recipient body weight (Kw/Rw) ratio on long-term graft function and survival. We investigated retrospectively whether there was any association between Kw/Rw ratio and long-term graft survival and function after a follow-up of >10 years. We studied a consecutive series of 123 adult-to-adult living kidney transplants. According to the Kw/Rw ratio, patients were divided into 3 groups: "low" (Kw/Rw <2.85; n = 29), "medium" (2.85 ≤ Kw/Rw < 4.04; n = 63), and "high" (≥4.04; n = 31). Among the 3 groups, the mean serum creatinine levels at 1 and 6 months as well as 1 year after transplantation were significantly lower among patients with a high Kw/Rw ratio than in those with a medium or low ratio, but serum creatinine levels at 3 and 5 years did not differ significantly (P = .394 and 0.620, respectively). Graft survival rates at 5 and 10 years after transplantation were significantly lower in the "low" group. We observed a significant association between Kw/Rw ratio and graft survival (P = .018). The Kw/Rw ratio is an important factor for long-term graft survival and early graft function. However, it did not significantly affect subsequent renal function.
    No preview · Article · Feb 2012 · Transplantation Proceedings
  • J K Hwang · H J Chun · I S Moon · J I Kim
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    ABSTRACT: Ipsilateral acute iliofemoral deep vein thrombosis (DVT) immediately after kidney transplantation is rare but highly morbid, resulting in allograft failure, rupture, or even death. Treatment modalities for iliofemoral DVT occurring just after transplantation are limited due to bleeding risk and impaired renal function. A 55-year-old woman with end-stage renal disease from hypertension underwent a living nonrelated donor procedure using a kidney from her husband. On postoperative day 1, the patient presented edema and pain in the right lower extremity associated with local heat and redness. The symptoms became aggravated with time. Duplex ultrasonography (US) revealed a DVT involving from the right femoral vein to the common iliac vein and an increased resistive index of 0.96 to 0.97. A venogram using carbon dioxide as the contrast medium showed also same findings as the duplex US. After inferior vena cava filter insertion, percutaneous transluminal thromboaspiration (PTA) was performed with complete removal of the thrombus. Early PTA with carbon dioxide as intravenous contrast material seemed to be an effective and safe procedure to treat this complication.
    No preview · Article · Jul 2011 · Transplantation Proceedings
  • J.K. Hwang · S.D. Kim · S.C. Park · B.S. Choi · J.I. Kim · C.W. Yang · Y.S. Kim · I.S. Moon
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    ABSTRACT: Kidneys with multiple renal arteries are increasingly procured for transplantation. To compare the outcomes of kidney transplantation using allografts with multiple arteries, we studied long-term graft function and survival according to their number of arterial anastomoses during an 18-year period from July 1, 1990, through December 31, 2008, in which only the recipient's external iliac artery or internal iliac artery was used for anastomosis (n = 1186). The recipients were divided into four groups: group I, single renal artery with single anastomosis (n = 890, 75.0%); group Il, multiple renal arteries, single anastomosis (n = 26, 2.2%); group Ill, multiple renal arteries, multiple anastomoses (n = 236, 19.9%); and group IV, polar artery ligation (n = 34, 2.9%). We compared the following variables patient and graft survivals; mean creatinine levels at 1 and 6 months, as well as 1-, 3-, and 5-years posttransplant; the number of acute rejection episodes, and the rates of vascular and urologic complications. The creatinine values and incidences of acute rejection episodes did not differ significantly (P = 0.399 and P = 0.990, respectively). There were no significant differences among the four groups in graft survival (P = 0.951), patient survival (P = 0.751), incidence of vascular (P = 0.999) or urologic complications (P = 0.371). The four groups were subdivided according to the recipient arterial anastomosis to the main graft renal artery. The subdivided groups showed no significant differences in graft or patient survival, or complications rates. The results indicated that multiplicity of renal arteries in kidney transplantation did not adversely affect allograft or patient survival compared with single renal artery transplantation. Moreover, the type of the arterial anastomosis (main renal artery end-to-end anastomosed to internal iliac artery or end-to-side anastomosed to external iliac artery appeared to not affect graft or patient survival or the incidence of vascular or urologic complications.
    No preview · Article · Dec 2010 · Transplantation Proceedings
  • I. S. Moon · J. K. Hwang · J. I. Kim · S. C. Park · C. W. Yang · S. N. Kim · Y. Koh

    No preview · Article · Jul 2010 · Transplantation
  • I. S. Moon · J. K. Hwang · J. I. Kim · C. W. Yang · S. N. Kim · Y. Koh

    No preview · Article · Jul 2010 · Transplantation

  • No preview · Article · Jul 2010 · Transplantation
  • A.-J. Choi · C.-J. Kim · Y.-J. Cho · J.-K. Hwang · C.-T. Kim
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    ABSTRACT: Food nanoemulsion systems consisting of water and oleoresin capsicum (OC), polyoxythylene sorbitan esters (Tween 20, 40, 60, and 80), propylene glycol (PG), sucrose monostearate (SM), and their corresponding mixtures were formulated to use as food vehicles. Tween 80 produced OC nanoemulsions with stable dispersions as one-phase systems, and the dertermined emulsification efficiencies clearly distinguished the ability of the various surfactants to emulsify OC. The nanoemulsions were prepared by both ultrasonication and self-assembly, and the nanoemulsion areas were determined using phase diagrams by measuring the sizes of the emulsions. One-phase nanoemulsions were presented, with a multiple cloudy region and phase separation that were dependent on the particle size of the emulsion. The OC nanoemulsions prepared by ultrasonication using systems of OC/Tween 80/water, OC/Tween 80/water+PG, and OC/Tween 80/water+SM, resulted in particle sizes ranging from 15 to 100 nm. Finally, the nanoemulsions maintained their initial sizes during storage, ranging from 65 to 92 nm.
    No preview · Article · Oct 2009
  • A.J. Choi · C.J. Kim · Y.J. Cho · J.K. Hwang · C.T. Kim
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    ABSTRACT: In this research, we investigated the optimum condition for the preparation of O/W nanoemulsion containing surfactants and oleoresin capsicum(OC) in fourcomponent systems, and characterized the structure and stability of nanoemulsions by using the ternary phase diagrams of systems. Various types of nanoemulsion including single-layer, double-layers and triple-layers nanoemulsions could be produced depending on the polyelectrolytes such as alginate and chitosan. O/W nanoemulsions of OC could be prepared by the ultrasonication process at the ration of mixture of OC:Tween 80(1:0.7) and by self-assembly method at the ratio of mixture of OCTween 80(1:3) with a particle size of 20-100nm and having a good stability during storage. The ultra-sonication method may be more powerful tool to prepare the nanoemulsion than the self-assembly process, it might be due to the formation capacity of nanoemulsion phase.
    No preview · Article · Jan 2008
  • A.-J. Choi · C.-J. Km · Y.-J. Cho · Y. Kim · J.Y. Cha · J.-K. Hwang · I.-H. Kim · C.-T. Kim
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    ABSTRACT: Physiochemical properties, such as yield and molecular weight distribution of polysaccharide fractions, of poly-saccharides in the enzymatic hydrolysates of purslane were investigated and characterized. A higher amount of micro nutrients, such as potassium (9,413 mg/100 g), phosphorus acid (539 mg/100 g), leucine, alanine, lysine, valine, glycine, and isoleucine, was present in whole purslane. The yield of water soluble polysaccharides (WSP) was 0.29,7.01, and 7.94% when extracted using room temperature water (RTW), hot-water (HW), and hot temperature/high pressure-water (HTPW), respectively, indicating that HW or HTPW extraction may be effective to obtain WSP from purslane. The average ratio of L-arabinose:D-galactose in the WSP was 37:49, 34:37, and 27:29, when extracted using RTW, HW, and HTPW, respectively. These results indicate that water was a suitable extraction solvent for preparation of the arabinogalactan component of whole purslane. A higher yield and total carbohydrate content was obtained by using Viscozyme L instead of Pectinex 5XL during extraction of the WSP, which indicates that enzymatic treatment of purslane may be an effective method to control the Mw of polysaccharides. Finally, it was confirmed that Viscozyme L is a suitable enzyme for the hydrolysis and separation of polysaccharides obtained from purslane.
    No preview · Article · Jan 2007
  • J.Y. Chung · J.H. Choo · M.H. Lee · J.K. Hwang
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    ABSTRACT: The occurrence of dental caries is mainly associated with oral pathogens, especially cariogenic Streptococcus mutans. Preliminary antibacterial screening revealed that the extract of Myristica fragrans, widely cultivated for the spice and flavor of foods, possessed strong inhibitory activity against S. mutans. The anticariogenic compound was successfully isolated from the methanol extract of M. fragrans by repeated silica gel chromatography, and its structure was identified as macelignan by instrumental analysis using 1D-NMR, 2D-NMR and EI-MS. The minimum inhibitory concentration (MIC) of macelignan against S. mutans was 3.9 microg/ml, which was much lower than those of other natural anticariogenic agents such as 15.6 microg/ml of sanguinarine, 250 microg/ml of eucalyptol, 500 microg/ml of menthol and thymol, and 1000 microg/ml of methyl salicylate. Macelignan also possessed preferential activity against other oral microorganisms such as Streptococcus sobrinus, Streptococcus salivarius, Streptococcus sanguis, Lactobacillus acidophilus and Lactobacillus casei in the MIC range of 2-31.3 microg/ml. In particular, the bactericidal test showed that macelignan, at a concentration of 20 microg/ml, completely inactivated S. mutans in 1 min. The specific activity and fast-effectiveness of macelignan against oral bacteria strongly suggest that it could be employed as a natural antibacterial agent in functional foods or oral care products.
    No preview · Article · Apr 2006 · Phytomedicine
  • H.H. Shin · C.T. Kim · Y.J. Cho · J.K. Hwang
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    ABSTRACT: To extract apple pectins, apple pomace (AP) was extruded under 14 different conditions of screw speed (250-350 rpm), feed rate of 30-40 kg/hr, and 20-30% moisture content using twin-screw extrusion. Response surface methodology (RSM), based on three variables by three-level factorial design, was employed to investigate effects of screw speed, feed rate, and moisture on dependent variables of extrudates, soluble dietary fiber (SDF), yield of anhydrogalacturonic acid (Y-AGA) representing pectin, and intrinsic viscosity ([eta]). Second order models were used to generate three-dimensional response surface for dependent variables, and their coefficients of determination (R-2) ranged from 0.96 to 0.99. Moisture content showed highest effect on solubilization of AP.
    No preview · Article · Feb 2005 · Food science and biotechnology

Publication Stats

421 Citations
50.18 Total Impact Points

Institutions

  • 2010-2014
    • Catholic University of Korea
      • College of Medicine
      Sŏul, Seoul, South Korea
  • 2000-2012
    • Yonsei University
      • Department of Biotechnology
      Sŏul, Seoul, South Korea
  • 1991
    • Rutgers, The State University of New Jersey
      • Department of Food Science
      New Brunswick, New Jersey, United States