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Seoul, South Korea

Song S.-J.,Korea Artificial Organ Center | Choi J.,Korea Artificial Organ Center | Park Y.-D.,Korea Artificial Organ Center | Lee J.-J.,Korea Artificial Organ Center | And 3 more authors.
Artificial Organs | Year: 2010

Bioprinting is an emerging technology for constructing tissue or bioartificial organs with complex three-dimensional (3D) structures. It provides high-precision spatial shape forming ability on a larger scale than conventional tissue engineering methods, and simultaneous multiple components composition ability. Bioprinting utilizes a computer-controlled 3D printer mechanism for 3D biological structure construction. To implement minimal pattern width in a hydrogel-based bioprinting system, a study on printing characteristics was performed by varying printer control parameters. The experimental results showed that printing pattern width depends on associated printer control parameters such as printing flow rate, nozzle diameter, and nozzle velocity. The system under development showed acceptable feasibility of potential use for accurate printing pattern implementation in tissue engineering applications and is another example of novel techniques for regenerative medicine based on computer-aided biofabrication system. © 2010, the Authors. Artificial Organs © 2010, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc. Source


Kim H.J.,Korea University | Yoo S.M.,Korea Artificial Organ Center | Jung J.S.,Korea University | Lee S.H.,Korea University | And 2 more authors.
Anaesthesia | Year: 2015

Summary We measured heating of isotonic saline by three fluid warmers in six experiments: saline at 5 C or 20 C delivered at 30, 50 or 100 ml.min-1. At the three flow rates, the enFLOW®, buddy lite™ and ThermoSens® systems heated 5 C saline to mean (SD) temperatures of: 41.1 (0.5) C, 37.7 (0.6) C and 39.1 (0.6) C; to 40.3 (0.8) C, 33.9 (1.6) C and 39.3 (0.7) C; and to 37.1 (0.8) C, 24.0 (1.3) C and 37.6 (1.0) C, respectively, p < 0.0001 for each experiment. The mean (SD) times taken to heat 5 C saline were: 16.6 (1.7) s, 258.4 (58.9) s and 134.2 (79.6) s; 16.9 (1.8) s, 256.2 (62.2) s and 182.5 (74.5) s; and 21.5 (1.5) s, 275.9 (49.3) s and 313.5 (18.0) s, respectively, p < 0.0003 for each experiment. The results for saline at 20 C were similar. The enFLOW system heated saline above 36 C faster than the ThermoSens system, whereas the buddy lite often failed to achieve 36 C. © 2014 The Association of Anaesthetists of Great Britain and Ireland. Source


Jung J.S.,Korea University | Jung J.S.,Korea Artificial Organ Center | Son H.S.,Korea University | Son H.S.,Korea Artificial Organ Center | And 5 more authors.
Transplantation Proceedings | Year: 2013

After heart transplantation (HT), transient right heart failure (RHF) is common. If it does not improve with appropriate medical therapy, we must consider mechanical support. Recently, extracorporeal membrane oxygenation (ECMO) has shown better results than a right ventricular assist device or retransplantation. Two HT patients with hypertrophic cardiomyopathy had cold ischemic times beyond >240 minutes. After HT, their right heart function worsened and was unresponsive to medical therapy. After our application of ECMO, weaning was successful and the patients were discharged without complication. Early application of ECMO for RHF after HT is a good option. © 2013 by Elsevier Inc. All rights reserved. Source


Jung J.S.,Korea University | Jung J.S.,Korea Artificial Organ Center | Son K.H.,Korea University | Son K.H.,Korea Artificial Organ Center | And 6 more authors.
Artificial Organs | Year: 2011

Vessel lumens that have been chronically narrowed by atherosclerosis should be increased in flow velocity and intrastenotic area pressure to maintain an equal flow. This might be followed by a decrease in hemodynamic energy, leading to a reduction of tissue perfusion. In this study, we compared hemodynamic energies according to degrees of stenotic vasculature between pulsatile flow and nonpulsatile flow. Cannuale with 25, 50, and 75% diameter stenosis (DS) were located at the outlet cannula. Using the Korea Hybrid ventricular assist device (KH-VAD) (pulsatile pump: group A) and Biopump (nonpulsatile pump: group B), constant flow of 2L/min was maintained then real-time flow and velocity in the proximal and distal part of the stenotic cannula were measured. The hemodynamic energies of two groups were compared. At 75% DS, proximal energy equivalent pressure (EEP) delivered to the distal end was only 41.9% (group A) and 42.5% (group B). As the percent EEP fell below 10%, pulsatility disappeared from the 50% stenosis in group A. The surplus hemodynamic energy (SHE) of group B at all degrees of stenosis must have been 0, which was also the case of group A at 75% stenosis. This research evaluated the hemodynamic energy on various degrees of DS in both pulsatile and nonpulsatile flow with mock system. Using a pulsatile pump, pulsatility disappeared above 50% DS while hemodynamic energy was maintained. Therefore, our results suggest that pulsatile flow has a better effect than nonpulsatile flow in reserving hemodynamic energy after stenotic lesion. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc. Source


Son K.H.,Korea University | Son K.H.,Korea Artificial Organ Center | Ahn C.B.,Korea Artificial Organ Center | Lee S.H.,Korea University | And 8 more authors.
Clinical Hemorheology and Microcirculation | Year: 2011

Purpose: The advantages of blood cardioplegia, which is used for myocardial protection during open heart surgeries, include superior oxygen-carrying capacities, better osmotic properties, and the presence of more antioxidants than a crystalloid counterpart. Although, hyperkalemic organ-preserving solutions for transplantation surgeries are known to decrease RBC deformability essential for tissue perfusion, only few studies have addressed the changes in RBC deformability after exposure to cardioplegic additives. The purpose of this study was to measure deformability and oxygen-delivery capacities in various blood cardioplegic solutions. Methods: Blood from eight healthy volunteers was used. Each sample (100 ml) was divided into 5 groups of 16 ml, and cardioplegia solutions were added (group NS; blood + normal saline, group K; blood + KCl, group D; blood + KCl + diltiazem, group A: blood + KCl + adenosine, group E: blood + KCl + neutrophil elastase inhibitor [Sivelestat]). All samples were incubated at a temperature of 8°C for 10 minutes. Deformability, NO level, 2,3-DPG, and ATP were measured. Results: There was no statistically significant difference (p = 0.92) in deformability between the groups. The NO levels were not significantly different (p = 0.86). The 2,3-DPG (p = 0.27) and ATP levels (p = 0.40) were not significantly different. Conclusions: The deformability and oxygen carrying functions of RBCs did not show a significant difference according to various components of cold blood cardioplegia during 10 minutes of incubation. © 2011 - IOS Press and the authors. All rights reserved. Source

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