• Journal of Biomedical Engineering Research
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• v.19 no.2
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• pp.153-162
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• 1998

It is needless to say that the nonlinear hemodynamic variables estimation is a very important study for the artificial heart. Even though it is important, there have not been satisfactory results which can be applied to the real world situations, In this paper, the problem of hemodynamic variables estimation for the moving-actuator type total artificial heart(MA-TAH) was studed. Multidimensional linear interpolation(MDI)scheme was used for the estimation. Proposed method was verified by in vitro test and showed good performance.

• Korean Journal of Veterinary Research
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• v.35 no.3
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• pp.595-601
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• 1995

Hemodynamic values were assessed in the cows diseased with mastitis. Hemodynamic testes were performed for white blood cell(WBC), red blood cell(RBC), packed cell volume(PCV), hemoglobin concentration, monocyte, eosinophil, neutrophil, lymphocyte, prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen, platelet concentrations, antithrombin-III and plasminogen activities. Significant alterations were observed in the mean values of most analytes. The numbers of monocytes, eosinophil, and neutrophil, and prothrombin time were increased while the number of lymphocyte, activated partial thromboplastin time, thrombin time, fibrinogen concentration, plasminogen activity and platelet concentration were decreased. The number of RBC, PCV, hemoglobin and antithrombin-III activity were unchanged compared with normal mean values. These data indicated that activation of hemodynamic mechanisms was initiated either directly by the endotoxin-releasing or indirectly by the inflammatory mediators released by response to etiologic agents. We suspected that the changes of hemodynamic values in the cows diseased with mastitis were very similar to those of experimental endotoxin-induced mastitis.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.4
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• pp.181-186
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• 2006

This study was undertaken to evaluate whether peroxisome proliferator-activated-receptor-gamma $(PPAR-{\gamma})$ agonist-rosiglitazone (ROSI) induces postischemic functional recovery in Langendorf heart model. Hearts isolated from normal rats were subjected to 20 min of normoxia or 25 min zero-flow ischemia followed by 50 min reperfusion. In this acute protocol, ROSI $(20\;{\mu}g/ml)$ administered 10 min before ischemia had no effect on hemodynamic cardiac function, but had protective effect on lipid peroxidation in in vitro experiments. In chronic protocol in which ROSI was given by daily gavage (4 mg/kg) for three consecutive days, ROSI could not prevent the hemodynamic alteration on cardiac performance, but has protective effect on the activity of superoxide dismutase (SOD). There was no significant difference in the contents of reduced glutathione (GSH) and catalase activity between ischemia-reperfusion (IR) and ROSI treated IR hearts. Although ROSI had no effect on hemodynamic factor, it had effect on antioxidant activity. Our results indicate that ROSI provides partial beneficial effects by inhibiting lipid peroxidation and/or recovering normal level of SOD activity in the ischemic reperfused heart.

• Korean Journal of Veterinary Service
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• v.18 no.2
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• pp.182-188
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• 1995

Hemodynamic values were assessed in cows with naturally mastatis. hemodynamic tests included WBC, RBC, PCV, Hemoglobin, Monocyte, Eosinophil, Neutrophil, Lymphocyte, and prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen, platelet, antithrombin-III, and plasminogen activities. Significant changes were observed in the mean values of most analytses : WBC, monocytes, eosinophil, neutrophil were increased and Iymphocyte were decreased. prothrombin time was increased： activated partial thromboplastin time, thrombin time. increased : activated partial thromboplastin time, thrombin time, fibrinogen concentration, plasminogen activity and platelet concentration were decreased : and RBC, PCV, hemoglobin and antithrombin-III activity were unchanged, compared with normal mean values. Thesse data indicated activation of hemodynamic mechanisms, initiated either directly by bacteria produced endotoxin of secondaly inflammatory mediators produced in response to caused bacteria and naturally acquired mastitis was very similar to the experimental endotoxin-induced mastitis.

• Journal of Ginseng Research
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• v.40 no.4
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• pp.462-465
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• 2016

In the present study, we investigated whether treatment with GBCK25 facilitated the recovery of hemodynamic parameters, left ventricle systolic pressure, left ventricular developed pressure, and electrocardiographic changes. GBCK25 significantly prevented the decrease in hemodynamic parameters and ameliorated the electrocardiographic abnormality. These results indicate that GBCK25 has distinct cardioprotective effects in rat heart.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.6-9
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• 2008

Analyzing the characteristics of blood flow in the blood vessels is very important to diagnose the circulatory diseases. In order to investigate the hemodynamic characteristics in vivo, the measurements of blood flows inside the extraembryonic arterial and venous blood vessels of chicken embryos were carried out using an in vivo micro-PIV technique. The circulatory diseases are closely related with the formation of abnormal hemodynamic shear stress regions, thereby it is important to get blood velocity and vessel's morphological information according to the vessel configuration and the flow conditions. In this study, the flow images of RBCs in blood vessels were obtained using a high-speed CMOS camera with a spatial resolution of approximately 14.6${\mu}$m${\times}$14.6${\mu}$m in the whole circulation network of blood vessels. The blood flows in the veins and arteries show steady laminar and unsteady pulsatile flow characteristics, respectively. The mean blood flows merged (in veins) and bifurcated (in arteries) smoothly into the main blood vessel and branches, respectively, without any flow separation or secondary flow which accompanying large variation of shear stress. Vorticity was high in the inner regions for both types of vessels, where the radius of curvature varied greatly. The instantaneous flows in the arterial blood vessels showed noticeable pulsatility due to the heart beat, and the main features of the velocity waveforms, including pulsatile shape, retrograde flow, mean velocity, maximum velocity and pulsatile frequency, were significantly dependent on the pulsatile condition which dominates the arterial blood flow. In near future, these in vivo experimental results of blood flow measured in various extraembryonic blood vessels would be very useful to understand the hemodynamic characteristics of human blood flows and various blood flow researches for clinically useful hemodynamic discoveries as well.

• The Korean Journal of Pain
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• v.9 no.1
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• pp.63-68
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• 1996

Background; Epidural analgesia for controlling labor pain has recently gained world-wide popularity. However, many patients scheduled for continuous epidural analgesia voice concern over harmful effects to their fetus and other possible complications such as hemodynamic changes, back pain and neurologic sequelae etc. The aim of this study was to evaluate the hemodynamic changes with and without epidural block as a measure to determine the safety of epidural analgesia during labor and delivery. Methods: Twenty healthy subjects were divided equally into two groups(Group 1 without epidural block, and Group 2 with epidural block) and serial hemodynamic measurements were taken in all subjects with transcutaneous impedence cardiography. The epidural catheter was inserted at the level of $L_{3,4}$ in Group 2 and analgesia was maintained using 0.25% bupivacaine mixed with fentanyl. Results: Cardiac output increased slightly with cervical dilatation in both groups, but no significant differences were found between the two groups. Similarly, no significant differences were found in blood pressures between the two groups. Stroke volume and end-diastolic volume indices were slightly decreased in group 1 and slightly increased in group 2. However, there were no significant differences between the two groups. The ejection fraction was nearly constant and ranging 56~59%. Conclusion: We concluded epidural analgesia for labor and delivery is a safe technique for the parturients since results indicated no significant differences in hemodynamic changes, as compared to the control group.

• Neonatal Medicine
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• v.17 no.2
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• pp.201-206
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• 2010

Purpose: Recently, after patent ductus arteriosus (PDA) ligation in preterm infants, unexplained hemodynamic instabilities are reported. To determine the incidence, risk factors and clinical manifestations of hemodynamic instability after PDA ligation in very low birth weight (VLBW) infants. Methods: This retrospective multicenter study enrolled 18 VLBW infants who underwent PDA ligation from January 2002 to February 2008. Hemodynamic instability defined as unexplained cardiopulmonary dysfunction with increased dependency on mechanical ventilation and decreased blood pressure. Results: The mean gestational age and birth weight (BW) of all infants were $27^{+6}{\pm}1^{+6}$ weeks and 951${\pm}$245 g. Hemodynamic instability group (HI) included seven infants (39%) and hemodynamic stability group (HS) included 11 infants (61%). Compared to HS, HI had lower BW (1,033${\pm}$285 g vs. 821${\pm}$126 g, P=0.048) and weight on operation day (1,195${\pm}$404 g vs. 893${\pm}$151 g, P=0.042), longer hospital days (105${\pm}$29 vs. 141${\pm}$39, P=0.038), more severe bronchopulmonary dysplasia (BPD), (no/mild/moderate/severe, 2/5/2/2 vs. 0/1/2/4, P=0.038) and higher preoperative $FiO_2$ (0.29${\pm}$0.06 vs. 0.38${\pm}$0.09, P=0.02). One case of mortality due to sepsis, which was not associated with ligation, was observed among HS. Conclusion: The incidence of hemodynamic instability after PDA ligation in VLBW infants was 39%. Low BW, low weight on operation day and preoperative high $FiO_2$ might be risk factors of hemodynamic instability after PDA ligation in VLBW infants. The hemodynamic instability could increase the severity of BPD and hospital days.

• Journal of Korean Neurosurgical Society
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• v.62 no.2
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• pp.183-192
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• 2019

Objective : The objective of this study was to analyze patient-specific blood flow in ruptured aneurysms using obtained non-Newtonian viscosity and to observe associated hemodynamic features and morphological effects. Methods : Five patients with acute subarachnoid hemorrhage caused by ruptured posterior communicating artery aneurysms were included in the study. Patients' blood samples were measured immediately after enrollment. Computational fluid dynamics (CFD) was conducted to evaluate viscosity distributions and wall shear stress (WSS) distributions using a patient-specific geometric model and shear-thinning viscosity properties. Results : Substantial viscosity change was found at the dome of the aneurysms studied when applying non-Newtonian blood viscosity measured at peak-systole and end-diastole. The maximal WSS of the non-Newtonian model on an aneurysm at peak-systole was approximately 16% lower compared to Newtonian fluid, and most of the hemodynamic features of Newtonian flow at the aneurysms were higher, except for minimal WSS value. However, the differences between the Newtonian and non-Newtonian flow were not statistically significant. Rupture point of an aneurysm showed low WSS regardless of Newtonian or non-Newtonian CFD analyses. Conclusion : By using measured non-Newtonian viscosity and geometry on patient-specific CFD analysis, morphologic differences in hemodynamic features, such as changes in whole blood viscosity and WSS, were observed. Therefore, measured non-Newtonian viscosity might be possibly useful to obtain patient-specific hemodynamic and morphologic result.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.10
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• pp.494-501
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• 2001

In this study, the effects of vascular parameter changes and electrodes on VOP measurement based on IPG were simulated mathematically. For the evaluation of the effects of hemodynamic changes on VOP, a mathematical model, which consists of cardiovascular system model and venous occlusion model, was developed and the model solution representing the blood flow and pressure in measuring point was found by 2nd order Runge-Kutta method. And, with sensitivity coefficients obtained from finite element solution of electric field in measuring point, the effects of electrode system on measurement were evaluated. As increasing the resistance, the venous capacitance was not changed but the venous outflows were decreased and the decreased compliance reduced the venous capacitance. And, for several configurations of round electrodes and band electrodes, the sensitivity coefficients were computed using the electric field distribution along deep vein. In conclusion, the proposed mathematical cardiovascular model could be applied to the simulation study on the effects of hemodynamic parameters on DVT diagnosis with IPG. And, also the sensitivity coefficients could provide effective electrode configuration for exact measurement of VOP.