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Choi SS, Cho SS, Ha TY, Hwang S, Lee SG, Kim YK. Intraoperative factors associated with delayed recovery of liver function after hepatectomy: analysis of 1969 living donors. Acta Anaesthesiol Scand 2016; 60:193-202. [PMID: 26830214 DOI: 10.1111/aas.12630] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 05/26/2015] [Accepted: 08/09/2015] [Indexed: 12/17/2022]
Abstract
BACKGROUND The safety of healthy living donors who are undergoing hepatic resection is a primary concern. We aimed to identify intraoperative anaesthetic and surgical factors associated with delayed recovery of liver function after hepatectomy in living donors. METHODS We retrospectively analysed 1969 living donors who underwent hepatectomy for living donor liver transplantation. Delayed recovery of hepatic function was defined by increases in international normalised ratio of prothrombin time and concomitant hyperbilirubinaemia on or after post-operative day 5. Univariate and multivariate logistic regression analyses were performed to determine the factors associated with delayed recovery of hepatic function after living donor hepatectomy. RESULTS Delayed recovery of liver function after donor hepatectomy was observed in 213 (10.8%) donors. Univariate logistic regression analysis showed that sevoflurane anaesthesia, synthetic colloid, donor age, body mass index, fatty change and remnant liver volume were significant factors for prediction of delayed recovery of hepatic function. Multivariate logistic regression analysis showed that independent factors significantly associated with delayed recovery of liver function after donor hepatectomy were sevoflurane anaesthesia (odds ratio = 3.514, P < 0.001), synthetic colloid (odds ratio = 1.045, P = 0.033), donor age (odds ratio = 0.970, P = 0.003), female gender (odds ratio = 1.512, P = 0.014) and remnant liver volume (odds ratio = 0.963, P < 0.001). CONCLUSIONS Anaesthesia with sevoflurane was an independent factor in predicting delayed recovery of hepatic function after donor hepatectomy. Although synthetic colloid may be associated with delayed recovery of hepatic function after donor hepatectomy, further study is required. These results can provide useful information on perioperative management of living liver donors.
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Song GW, Lee SG, Hwang S, Kim KH, Ahn CS, Moon DB, Ha TY, Jung DH, Park GC, Kim WJ, Sin MH, Yoon YI, Kang WH, Kim SH, Tak EY. ABO-Incompatible Adult Living Donor Liver Transplantation Under the Desensitization Protocol With Rituximab. Am J Transplant 2016; 16:157-70. [PMID: 26372830 DOI: 10.1111/ajt.13444] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 05/29/2015] [Accepted: 06/24/2015] [Indexed: 01/25/2023]
Abstract
ABO incompatibility is no longer considered a contraindication for adult living donor liver transplantation (ALDLT) due to various strategies to overcome the ABO blood group barrier. We report the largest single-center experience of ABO-incompatible (ABOi) ALDLT in 235 adult patients. The desensitization protocol included a single dose of rituximab and total plasma exchange. In addition, local graft infusion therapy, cyclophosphamide, or splenectomy was used for a certain time period, but these treatments were eventually discontinued due to adverse events. There were three cases (1.3%) of in-hospital mortality. The cumulative 3-year graft and patient survival rates were 89.2% and 92.3%, respectively, and were comparable to those of the ABO-compatible group (n = 1301). Despite promising survival outcomes, 17 patients (7.2%) experienced antibody-mediated rejection that manifested as diffuse intrahepatic biliary stricture; six cases required retransplantation, and three patients died. ABOi ALDLT is a feasible method for expanding a living liver donor pool, but the efficacy of the desensitization protocol in targeting B cell immunity should be optimized.
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Lee SG, Moon DB, Hwang S, Ahn CS, Kim KH, Song GW, Jung DH, Ha TY, Park GC, Jung BH. Liver transplantation in Korea: past, present, and future. Transplant Proc 2015; 47:705-8. [PMID: 25891715 DOI: 10.1016/j.transproceed.2015.02.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 02/25/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE This study reviewed the past and present status of liver transplantation (LT) and outlooks for the future of LT in Korea. METHOD The first LT in Korea was successfully performed using a deceased donor graft in 1988. Pediatric and adult living donor liver transplantations (LDLTs) were initiated in 1994 and 1997, respectively. From 1988 to 2013, 10,581 LTs were performed at 40 centers, whereas LDLT accounted for 76.5% of all LTs. RESULTS In the early 1990s, the deceased organ donation rate was less than 1.5 per million population (PMP) per year, but it increased to 5 PMP beginning in 2008. Despite the increasing number of deceased donor liver transplantations (DDLTs), high prevalence of hepatitis B virus (HBV)-induced cirrhosis and hepatocellular carcinoma (HCC) has provoked persistent performance of adult LDLT with technical advancement including middle hepatic vein (MHV) reconstruction of right lobe graft and dual graft LDLT with 1 nationwide donor mortality. CONCLUSION The number of LTs in Korea in 2010 was 23.2 PMP (1042 LTs/45 million population), lower than 23.5 PMP of Spain, but higher than 20 PMP of the United States. However, future LT numbers may decrease because of lowering the HBV carrier rate (neonatal HBV universal vaccination began in 1992), new potent anti-HBV agents, and lowest birth rate (1.22 children per family) with a decrease of potential live donors.
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Kwon D, Min S, Hwang S, Kim M. Measurement of soft tissue change using 3D scanner in orthognathic surgery patient. Int J Oral Maxillofac Surg 2015. [DOI: 10.1016/j.ijom.2015.08.207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Min S, Nam H, Kwon D, Hwang S, Kim M. Correlation of maxillo-mandibular skeletal changes and change of lip canting in two jaw orthognathic surgery for correction of facial asymmetry. Int J Oral Maxillofac Surg 2015. [DOI: 10.1016/j.ijom.2015.08.705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Park H, Yang J, Son Y, Choi E, Hwang S. Functional connectivity between hippocampal subdivision and extra-hippocampal regions in the mesial temporal lobe epilepsy. J Neurol Sci 2015. [DOI: 10.1016/j.jns.2015.08.784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Song GW, Ahn CS, Lee SG, Hwang S, Kim KH, Moon DB, Ha TY, Jung DH, Park GC, Kang SH, Jung BH, Kim N. Correlation between risk of hepatitis B virus recurrence and tissue expression of covalently closed circular DNA in living donor liver transplant recipients treated with high-dose hepatitis B immunoglobulin. Transplant Proc 2015; 46:3548-53. [PMID: 25498087 DOI: 10.1016/j.transproceed.2014.06.074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 05/05/2014] [Accepted: 06/17/2014] [Indexed: 01/16/2023]
Abstract
BACKGROUND AND AIMS Despite the application of prophylaxis, the risk of hepatitis B virus (HBV) recurrence remains. However, actual mechanism(s) and definite risk factor(s) are obscure. The present study examined the correlation between the HBV load in liver explants and post-liver transplant (OLT) HBV recurrence. METHODS HBV DNA was extracted from liver tissue taken from 50 living donor OLT (LDLT) patients using the QuickGene DNA Tissue Kit S (Fujifilm, Tokyo, Japan) and subjected to real-time polymerase chain reaction with the following primers: 5'-CACATGGCCTCCAAGGAGTAA-3' (forward primer) and 5'-TGAGGGTCTCTCTCTTCCTCTTGT-3' (reverse primer). To prevent HBV infection, patients were treated daily with high-dose (10,000 IU) hepatitis B immunoglobulin (HBIG) for the first week after LDLT. They then received weekly doses for the next month and then monthly doses for ≤1 year. If the anti-hepatitis surface antigen antibody titer was <1,000 IU/L, an antiviral agent (AVA) was added to the regimen. RESULTS The mean (±SD) tissue HBV DNA and covalently closed circular DNA (cccDNA) loads were -0.8 ± 1.2 (range, -2.9 to 2.6) and -2.3 ± 1.1 (range, -4.6 to 0.6) log10 copies/cell, respectively. There was a significant correlation between serum and tissue HBV DNA (r = 0.65; P = .00) and cccDNA concentrations (r = 0.55; P = .00). Six patients suffered HBV recurrence and 9 required additional AVA. There was no direct correlation between HBV recurrence and tissue cccDNA concentration. However, the concentration of cccDNA was significantly greater those patients suffering recurrence and receiving AVA treatment (high-risk group). CONCLUSION High tissue cccDNA concentrations may be a risk factor for HBV recurrence despite high-dose HBIG prophylaxis.
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Jang S, Lee JS, Hwang S, Kahng B. Ashkin-Teller model and diverse opinion phase transitions on multiplex networks. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:022110. [PMID: 26382347 DOI: 10.1103/physreve.92.022110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Indexed: 06/05/2023]
Abstract
Multiplex networks (MNs) have become a platform of recent research in network sciences because networks in many real-world systems interact and function together. One of the main scientific issues in MNs is how the interdependence changes the emerging patterns or phase transitions. Until now, studies of such an issue have concentrated on cluster-breakdown phenomena, aiming to understand the resilience of the system under random failures of edges. These studies have revealed that various phase transition (PT) types emerge in MNs. However, such studies are rather limited to percolation-related problems, i.e., the limit q→1 of the q-state Potts model. Thus, a systematic study of opinion formation in social networks with the effect of interdependence between different social communities, which may be seen as the study of the emerging pattern of the Ising model on MNs, is needed. Here we study a well-known spin model called the Ashkin-Teller (AT) model in scale-free networks. The AT model can be regarded as a model for interacting systems between two species of Ising spins placed on respective layers in double-layer networks. Our study shows that, depending on the interlayer coupling strength and a network topology, unconventional PT patterns can also emerge in interaction-based phenomena: continuous, discontinuous, successive, and mixed-order PTs and a continuous PT not satisfying the scaling relation. The origins of such rich PT patterns are elucidated in the framework of Landau-Ginzburg theory.
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Kong YG, Ha TY, Kang JW, Hwang S, Lee SG, Kim YK. Incidence and Predictors of Increased Coronary Calcium Scores in Liver Transplant Recipients. Transplant Proc 2015; 47:1933-8. [DOI: 10.1016/j.transproceed.2015.05.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 05/22/2015] [Indexed: 01/14/2023]
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Park M, Choi Y, Cho A, Hwang S, Cha J, Lee N, Yun M. SU-D-201-02: Prediction of Delivered Dose Based On a Joint Histogram of CT and FDG PET Images. Med Phys 2015. [DOI: 10.1118/1.4923910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Fehr D, Schmidtlein C, Hwang S, Deasy J, Veeraraghavan H. TU-G-204-02: Automatic Sclerotic Bone Metastases Detection in the Pelvic Region From Dual Energy CT. Med Phys 2015. [DOI: 10.1118/1.4925766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Jung DH, Hwang S, Ahn CS, Kim KH, Moon DB, Ha TY, Song GW, Park GC, Lee SG. Safety and usefulness of warm dissection technique during liver graft retrieval from deceased donors. Transplant Proc 2015; 47:576-9. [PMID: 25891689 DOI: 10.1016/j.transproceed.2014.12.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 12/31/2014] [Indexed: 11/16/2022]
Abstract
BACKGROUND For deceased-donor liver graft retrieval, the warm dissection technique of hilar dissection before perfusion had been the standard procedure in the early period of liver transplantation. Thereafter, the cold dissection technique of in situ flushing and hilar dissection after perfusion has been preferred in many transplantation centers for rapid procurement of multiple organs. This study intended to assess the safety and usefulness of the warm dissection technique used in deceased-donor liver transplantation. METHODS This study analyzed a single surgeon's experience of the warm dissection technique for 165 cases of liver graft retrieval, regarding the prolongation of retrieval operation time, retrieval-associated graft injury, and recipient outcomes. RESULTS An additional 20 to 40 minutes was required for warm dissection. The incidence of retrieval-associated graft injury was 13 (7.9%), in which hepatic parenchymal injury was detected in 7 (capsular tear in 6 and subcapsular hematoma in 1) and vascular injury in 6 (celiac axis injury in 5 and common hepatic artery injury in 1). There was no other episode of injury at the branch artery, vena cava, portal vein, and bile duct. There was no significant difference of 1-year graft survival rates between liver grafts with and without graft injury (83% vs 83.3%, P = .73). CONCLUSIONS When the vital signs of deceased donor are stable, the warm dissection technique may be helpful to decrease the cold ischemic preservation time because the risk of graft injury is acceptably low and it provides more time for recipient preparation, thus giving potential advantages for marginal liver grafts.
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Kim SH, Ha YE, Youn JC, Park JS, Sung H, Kim MN, Choi HJ, Lee YJ, Kang SM, Ahn JY, Choi JY, Kim YJ, Lee SK, Kim SJ, Peck KR, Lee SO, Kim YH, Hwang S, Lee SG, Ha J, Han DJ. Fatal scedosporiosis in multiple solid organ allografts transmitted from a nearly-drowned donor. Am J Transplant 2015; 15:833-40. [PMID: 25639881 DOI: 10.1111/ajt.13008] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/05/2014] [Accepted: 09/11/2014] [Indexed: 01/25/2023]
Abstract
Scedosporium spp. is the most common mold infection in pneumonia resulting from near-drowning. Three fatal scedosporiosis cases developed after solid organ transplantation, probably transmitted from the nearly-drowned donor. One heart transplant recipient and two kidney transplant recipients developed fatal scedosporiosis following deceased donor transplantation from the same donor, a nearly-drowned victim of a suicide attempt. Genotypically, indistinguishable strains of Scedosporium auratiacum were recovered from the three recipients. Two liver transplant recipients from the same donor received prophylactic voriconazole without any subsequent signs of infection. To determine the safety of donation from nearly-drowned donors, a national traceback investigation was also performed of the causes of deaths in all transplant recipients who received organs from drowned donors between 2001 and 2013. Over 13 years, 2600 deceased donor transplants were performed in Korea. Among these 2600 deceased donor transplants, 27 (1%) victims of drowning donated their organs. From these 27 donors, 84 patients received organ transplants and 18 died, including the above three. We found no microbiologic evidence of invasive mold transmission from the nearly-drowned donors to the other 15 recipients. Although disseminated infection in the donor could not be demonstrated by culture, undiagnosed disseminated donor infection and transmission of Scedosporium spp. should be considered in near-drowning events.
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Ha TY, Hwang S, Moon DB, Ahn CS, Kim KH, Song GW, Jung DH, Park GC, Park HW, Park YH, Kang SH, Jung BH, Lee SG. Long-term survival analysis of liver transplantation for hepatocellular carcinoma with bile duct tumor thrombus. Transplant Proc 2015; 46:774-7. [PMID: 24767346 DOI: 10.1016/j.transproceed.2013.10.053] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Accepted: 10/01/2013] [Indexed: 11/25/2022]
Abstract
BACKGROUND Long-term prognosis of liver transplantation (LT) for hepatocellular carcinoma (HCC) with macroscopic bile duct tumor thrombus (BDTT) has not been well assessed. This study intended to analyze the post-transplantation outcomes in patients who had HCC with macroscopic BDTT. METHODS A retrospective study was performed with 14 patients who underwent LT for HCC with BDTT (0.7%) after selection from an institutional database of 2052 adult LT cases. RESULTS Types of LT were living donor LT in 13 and deceased donor LT in 1. The extents of BDTT were Ueda type 1 in 4, type 2 in 3, and type 3 in 7. Milan criteria were met in 8 (57.1%). Concurrent bile duct resection was performed in 7 (50%). Mean model for end-stage liver disease score was 18.7 ± 4.9. Mean graft-recipient weight ratio was 1.2 ± 0.3. There was one case of perioperative mortality and one case of HCC-unrelated late mortality. Cumulative HCC recurrence rates were 15.4% at 1 year, 46.2% at 3 years, and 46.2% at 5 years. Overall patient survival rates were 92.9% at 1 year, 57.1% at 3 years, and 50% at 5 years. Univariate risk factor analyses revealed that only macrovascular invasion was a significant risk factor for HCC recurrence (P = .019). CONCLUSIONS The results of this study revealed that LT for HCC with macroscopic BDTT has a high risk of post-transplantation HCC recurrence; therefore, further large-volume studies are necessary to elucidate the risk factors.
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Ha TY, Hwang S, Kim KH, Lee YJ, Ahn CS, Moon DB, Song GW, Park KM, Kim N, Lee SG. Expression pattern analysis of hepatocellular carcinoma tumor markers in viral hepatitis B and C patients undergoing liver transplantation and resection. Transplant Proc 2015; 46:888-93. [PMID: 24767373 DOI: 10.1016/j.transproceed.2013.12.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 11/30/2013] [Accepted: 12/11/2013] [Indexed: 12/15/2022]
Abstract
BACKGROUND This study was conducted to compare the expression patterns of serum alpha-fetoprotein (AFP) and proteins induced by vitamin K absence or antagonist-II (PIVKA-II) in hepatocellular carcinoma (HCC) patients undergoing liver transplantation (LT) and resection at a high-volume single institution. METHODS First, 663 liver transplant recipients with HCC were selected. They were divided into hepatitis B virus (HBV) (n = 628) and hepatitis C virus (HCV) groups (n = 35). Their medical records were retrospectively reviewed. Second, another cohort of 2709 patients who underwent HCC resection included 2258 HBV, 143 HCV, and 308 non-HBV non-HCV (NBNC) patients. RESULTS In the transplantation group, pretransplantation AFP level >20 ng/mL was observed in 42.5% of HBV patients and 60% of HCV patients (P = .042). PIVKA-II level >40 mAU/mL was observed in 30.6% of HBV patients and 42.9% of HCV patients (P = .127). In the resection group, a preoperative AFP level >20 ng/mL was observed in 51.7% of HBV patients and 43.3% of HCV patients (P = .052). PIVKA-II level >40 mAU/mL was observed in 59.7% of HBV patients and 56.6% of HCV patients (P = .47). Preoperative AFP level >20 ng/mL and PIVKA-II level >40 mAU/mL were observed in 35.7% and 61% of NBNC patients, respectively. Receiver-operator characteristic curve analyses revealed that the expression pattern of PIVKA-II in patients with elevated AFP level was not predictable and vice versa, regardless of background liver diseases. CONCLUSIONS This study indicates that serum AFP and PIVKA-II may be expressed variably regardless of the types of background liver disease. Further large-volume multicenter studies are needed to evaluate the possibility of the etiology-dependent expression of tumor markers.
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Park CS, Jung BH, Hwang S, Park YH, Kang SH, Park GC, Song GW, Jung DH, Ahn CS, Kim KH, Moon DB, Ha TY, Lee SG. External biliary drainage in living donor liver transplantation using duct-to-duct anastomosis. Transplant Proc 2015; 46:678-81. [PMID: 24767322 DOI: 10.1016/j.transproceed.2013.11.150] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/01/2013] [Accepted: 11/27/2013] [Indexed: 12/26/2022]
Abstract
PURPOSE This study compared the incidence of biliary complication (BC) in adult living donor liver transplant recipients who underwent right-lobe duct-to-duct anastomosis (DDA) with or without external biliary drainage (EBD) and intended to optimize EBD tube clamping. METHODS This study consisted of a retrospective assessment of EBD effect and a prospective trial for EBD tube-clamping optimization. The retrospective study included the EBD group (n = 208) and the non-EBD group (n = 145). The prospective study included 60 patients with EBD. RESULTS In the retrospective study, single DDA was performed in 83.7% of the EBD group and 80.7% of the non-EBD group (P = .47). One-year overall incidence of BC was 14.4% in the EBD group and 16.8% in the non-EBD group (P = .48). The incidence of early anastomotic bile leakage was 1.0% in the EBD group and 4.8% in the non-EBD group (P = .036). In the prospective study, there was no difference in tube-clamping success rates between low- and high-output EBD groups. There was also no statistical difference between the success and failure groups in terms of graft duct size, liver function tests, and post-transplant days at tube clamping. CONCLUSIONS The size of our EBD tube was too small for the graft duct size, therefore its main role appeared to be early biliary decompression, which helped prevent bile leakage and also simplified the route of cholangiogram in detecting early BC. Hence, EBD is worthy of performing in selected patients with a high risk of anastomotic bile leak.
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Park YH, Hwang S, Song GW, Jung DH, Ahn CS, Kim KH, Moon DB, Ha TY, Park GC, Kim N, Lee SG. Correlation between mycophenolic acid blood level and renal dysfunction in stable liver transplant recipients receiving mycophenolate monotherapy. Transplant Proc 2015; 46:811-5. [PMID: 24767354 DOI: 10.1016/j.transproceed.2013.12.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 11/30/2013] [Accepted: 12/11/2013] [Indexed: 10/25/2022]
Abstract
PURPOSE Mycophenolate mofetil (MMF) is frequently used after liver transplantation (OLT). Mycophenolic acid (MPA) metabolites are eliminated primarily via the kidneys. If renal function declines, clearance is significantly impaired. The aim of this study was to reveal the renal function-dependent changes of MPA level in stable adult OLT recipients receiving MMF monotherapy. METHODS Sixty-five OLT recipients were selected from our OLT database of >3500 cases. All had undergone MMF monotherapy with a daily MMF dose of 1000 mg or 1500 mg for more than 2 years, primarily because they could not tolerate calcineurin inhibitors. Their clinical profiles, including MPA therapeutic drug monitoring (TDM) and renal function, were analyzed as a cross-sectional study. RESULTS For the group treated with 1000 mg MMF (n = 40), the 12-hour MPA trough level was 1.20 ± 0.35 μg/mL with serum creatinine (Cr) level ≤1.4 mg/dL in 13 patients; it was 2.78 ± 1.19 μg/mL with Cr >1.4 mg/dL in 16 patients not undergoing hemodialysis and 3.83 ± 0.87 μg/mL in 11 patients undergoing hemodialysis (P < .001). For the group treated with 1500 mg MMF (n = 25), the MPA trough level was 2.23 ± 0.99 μg/mL with Cr ≤1.4 mg/dL in 6 patients; it was 2.81 ± 0.99 μg/mL with Cr >1.4 mg/dL in 18 patients not undergoing hemodialysis and 3.5 μg/mL in 1 patient undergoing hemodialysis (P = .21). CONCLUSIONS Considering the potential therapeutic range of MPA, the suggested MMF dosage for Korean adult OLT recipients requiring hemodialysis may be set around 1000 mg per day. We suggest adjusting the MMF dosage on an individualized basis according to the results of MPA TDM, particularly for patients with markedly impaired renal function.
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Hwang S, Choi S, Lee D, Kahng B. Efficient algorithm to compute mutually connected components in interdependent networks. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:022814. [PMID: 25768559 DOI: 10.1103/physreve.91.022814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Indexed: 06/04/2023]
Abstract
Mutually connected components (MCCs) play an important role as a measure of resilience in the study of interdependent networks. Despite their importance, an efficient algorithm to obtain the statistics of all MCCs during the removal of links has thus far been absent. Here, using a well-known fully dynamic graph algorithm, we propose an efficient algorithm to accomplish this task. We show that the time complexity of this algorithm is approximately O(N(1.2)) for random graphs, which is more efficient than O(N(2)) of the brute-force algorithm. We confirm the correctness of our algorithm by comparing the behavior of the order parameter as links are removed with existing results for three types of double-layer multiplex networks. We anticipate that this algorithm will be used for simulations of large-size systems that have been previously inaccessible.
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Hwang S, Choi HS, Kim KM, Rhee Y, Lim SK. Associations between serum 25-hydroxyvitamin D and bone mineral density and proximal femur geometry in Koreans: the Korean National Health and Nutrition Examination Survey (KNHANES) 2008-2009. Osteoporos Int 2015; 26:163-71. [PMID: 25262060 DOI: 10.1007/s00198-014-2877-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 08/26/2014] [Indexed: 12/31/2022]
Abstract
UNLABELLED The association between 25-hydroxyvitamin D (25(OH)D) levels and bone mineral density (BMD) and proximal femur bone geometry was examined in the Korean population. A positive relationship between skeletal health and 25(OH)D levels was observed. However, there were no significant differences in skeletal health between the groups with 25(OH)D level of 50-75 nmol/L and greater than 75 nmol/L. INTRODUCTION Vitamin D plays an important role in calcium and phosphate homeostasis and normal mineralization of bone. However, the optimal level of vitamin D for skeletal health has not been clearly established. We analyzed the associations between serum 25(OH)D and BMD and proximal femur bone geometry and determined the optimal 25(OH)D level. METHODS This was a cross-sectional study of 10,062 participants (20-95 years, 4,455 men, 5,607 women) in the Fourth Korea National Health and Nutrition Examination Surveys (KNHANES IV) conducted from 2008 to 2009. Participants were divided into groups according to 25(OH)D level (<25, 25-50, 50-75, and ≥75 nmol/L). BMD and proximal femur geometric indices were measured. RESULTS The group with 25(OH)D levels of 50-75 nmol/L had greater bone density values, with the exception of the lumbar spine, and also had greater femur neck cortical thickness, cross-sectional area, and cross-sectional moment of inertia, as well as a lesser buckling ratio than the groups with 25(OH)D level of 25-50 nmol/L and less than 25 nmol/L. However, there were no significant differences in BMD and proximal femur geometry properties between the groups with 50-75 nmol/L and greater than 75 nmol/L of 25(OH)D. CONCLUSION The skeletal outcomes, including BMD and proximal femur geometric indices observed in this study, suggest that serum 25(OH)D levels of 50 to <75 nmol/L are optimal for skeletal health.
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Hwang S, Lee DS, Kahng B. Blind and myopic ants in heterogeneous networks. Phys Rev E 2014; 90:052814. [PMID: 25493841 DOI: 10.1103/physreve.90.052814] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Indexed: 11/07/2022]
Abstract
The diffusion processes on complex networks may be described by different Laplacian matrices due to heterogeneous connectivity. Here we investigate the random walks of blind ants and myopic ants on heterogeneous networks: While a myopic ant hops to a neighbor node every step, a blind ant may stay or hop with probabilities that depend on node connectivity. By analyzing the trajectories of blind ants, we show that the asymptotic behaviors of both random walks are related by rescaling time and probability with node connectivity. Using this result, we show how the small eigenvalues of the Laplacian matrices generating the two random walks are related. As an application, we show how the return-to-origin probability of a myopic ant can be used to compute the scaling behaviors of the Edwards-Wilkinson model, a representative model of load balancing on networks.
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Kong YG, Kang JW, Kim YK, Seo H, Lim TH, Hwang S, Hwang GS, Lee SG. Preoperative coronary calcium score is predictive of early postoperative cardiovascular complications in liver transplant recipients. Br J Anaesth 2014; 114:437-43. [PMID: 25416273 DOI: 10.1093/bja/aeu384] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Coronary computed tomographic angiography (coronary CT) is a non-invasive test for diagnosis of cardiac function. Coronary calcium scores determined by coronary CT are associated with cardiovascular risk factors. However, no studies have investigated the association between coronary calcium scores and cardiovascular complications after liver transplantation (LT). We therefore evaluated the utility of preoperative coronary calcium scores for predicting early postoperative cardiovascular complications in LT recipients. METHODS Between 2010 and 2012, 443 LT recipients were analysed retrospectively. Preoperative cardiovascular assessments, including coronary CT, were performed. A coronary calcium score >400 was defined as a positive finding. Predictive factors of early postoperative cardiovascular complications were evaluated by univariate and multivariate analyses. Major cardiovascular complications occurring during a period of 1 month after LT were noted. RESULTS Of the 443 patients, 38 (8.6%) experienced one or more cardiovascular complications. Positive coronary CT findings were seen in 11 (2.5%) patients. In the multivariate analysis, a coronary calcium score >400 {odds ratio (OR)=4.62 [95% confidence interval (CI): 1.14-18.72], P=0.032} and female sex [OR=2.76 (1.37-5.57), P=0.005] were predictive of cardiovascular complications. CONCLUSIONS A preoperative coronary calcium score of >400 predicted cardiovascular complications occurring 1 month after LT, suggesting that preoperative evaluation of coronary calcium scores could help predict early postoperative cardiovascular complications in LT recipients.
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97
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Lee JS, Hwang S, Yeo J, Kim D, Kahng B. Ground-state energy of the q-state Potts model: The minimum modularity. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:052140. [PMID: 25493772 DOI: 10.1103/physreve.90.052140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Indexed: 06/04/2023]
Abstract
A wide range of interacting systems can be described by complex networks. A common feature of such networks is that they consist of several communities or modules, the degree of which may quantified as the modularity. However, even a random uncorrelated network, which has no obvious modular structure, has a finite modularity due to the quenched disorder. For this reason, the modularity of a given network is meaningful only when it is compared with that of a randomized network with the same degree distribution. In this context, it is important to calculate the modularity of a random uncorrelated network with an arbitrary degree distribution. The modularity of a random network has been calculated [Reichardt and Bornholdt, Phys. Rev. E 76, 015102 (2007)PLEEE81539-375510.1103/PhysRevE.76.015102]; however, this was limited to the case whereby the network was assumed to have only two communities, and it is evident that the modularity should be calculated in general with q(≥2) communities. Here we calculate the modularity for q communities by evaluating the ground-state energy of the q-state Potts Hamiltonian, based on replica symmetric solutions assuming that the mean degree is large. We found that the modularity is proportional to 〈sqrt[k]〉/〈k〉 regardless of q and that only the coefficient depends on q. In particular, when the degree distribution follows a power law, the modularity is proportional to 〈k〉^{-1/2}. Our analytical results are confirmed by comparison with numerical simulations. Therefore, our results can be used as reference values for real-world networks.
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98
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Hwang S, Lee DS, Kahng B. Fast algorithm for relaxation processes in big-data systems. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:043303. [PMID: 25375619 DOI: 10.1103/physreve.90.043303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Indexed: 06/04/2023]
Abstract
Relaxation processes driven by a Laplacian matrix can be found in many real-world big-data systems, for example, in search engines on the World Wide Web and the dynamic load-balancing protocols in mesh networks. To numerically implement such processes, a fast-running algorithm for the calculation of the pseudoinverse of the Laplacian matrix is essential. Here we propose an algorithm which computes quickly and efficiently the pseudoinverse of Markov chain generator matrices satisfying the detailed-balance condition, a general class of matrices including the Laplacian. The algorithm utilizes the renormalization of the Gaussian integral. In addition to its applicability to a wide range of problems, the algorithm outperforms other algorithms in its ability to compute within a manageable computing time arbitrary elements of the pseudoinverse of a matrix of size millions by millions. Therefore our algorithm can be used very widely in analyzing the relaxation processes occurring on large-scale networked systems.
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Rahman MS, Kwon WS, Lee JS, Kim J, Yoon SJ, Park YJ, You YA, Hwang S, Pang MG. Sodium nitroprusside suppresses male fertility in vitro. Andrology 2014; 2:899-909. [PMID: 25180787 DOI: 10.1111/j.2047-2927.2014.00273.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 07/30/2014] [Accepted: 08/11/2014] [Indexed: 11/28/2022]
Abstract
Sodium nitroprusside is a nitric oxide donor involved in the regulation of the motility, hyperactivation, capacitation, and acrosome reaction (AR) of spermatozoa. However, the molecular mechanism underlying this regulation has not yet been elucidated. Therefore, this study was designed to evaluate the molecular basis for the effects of sodium nitroprusside on different processes in spermatozoa and its consequences on subsequent oocyte fertilization and embryo development. In this in vitro study, mouse spermatozoa were incubated with various concentrations of sodium nitroprusside (1, 10, and 100 μM) for 90 min. Our results showed that sodium nitroprusside inhibited sperm motility and motion kinematics in a dose-dependent manner by significantly enhancing intracellular iron and reactive oxygen species (ROS), and decreasing Ca(2+), and adenosine triphosphate levels in spermatozoa. Moreover, short-term exposure of spermatozoa to sodium nitroprusside increased the tyrosine phosphorylation of sperm proteins involved in PKA-dependent regulation of intracellular calcium levels, which induced a robust AR. Finally, sodium nitroprusside significantly decreased the rates of fertilization and blastocyst formation during embryo development. Based on these results, we propose that sodium nitroprusside increases ROS production and precocious AR may alter overall sperm physiology, leading to poor fertilization and compromised embryonic development.
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Kim S, Hwang S. A Retrospective Analysis of the Relation Between Durations of Adjuvant Chemotherapy with Its Effects on Overall Survival and Relapse Free Survival in Stage Ii or III Gastric Cancer. Ann Oncol 2014. [DOI: 10.1093/annonc/mdu334.43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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