• Journal of Chest Surgery
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• v.44 no.2
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• pp.89-98
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• 2011

Background: Although considerable efforts have been made to improve the graft patency in coronary artery bypass surgery, the role of biomechanical factors remains underrecognized. The aim of this study is to investigate the influences of geometric configurations of the bypass graft on hemodynamic characteristics in relation to anastomosis. Materials and Methods: The Numerical analysis focuses on understanding the flow patterns for different values of inlet and distal diameters and graft angles. The Blood flow field is treated as a two-dimensional incompressible laminar flow. A finite volume method is adopted for discretization of the governing equations. The Carreau model is employed as a constitutive equation for blood. In an attempt to obtain the optimal aorto-coronary bypass conditions, the blood flow characteristics are analyzed using in vitro models of the end-to-side anastomotic angles of $45^{\circ}$, $60^{\circ}$ and $90^{\circ}$. To find the optimal graft configurations, the mass flow rates at the outlets of the four models are compared quantitatively. Results: This study finds that Model 3, whose bypass diameter is the same as the inlet diameter of the stenosed coronary artery, delivers the largest amount of blood and the least pressure drop along the arteries. Conclusion: Biomechanical factors are speculated to contribute to the graft patency in coronary artery bypass grafting.

• The Journal of Korean Medicine
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• v.29 no.5
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• pp.52-66
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• 2008

Objectives :Ginkgo-Chunghyul-dan (GCHD) is newly developed herbal medicine to prevent and treat stroke. In this study, we investigated whether the GCHD had antioxidant activity and anti-platelet aggregation effect in vitro and hypolipidemic activities in vivo. Methods :Anti-oxidant activity of GCHD was measured using the Blois method, anti-platelet effect of GCHD was assessed by the Born method, and hypolipidemic activities of GCHD were evaluated in corn oil- or Triton WR-1339-induced and cholesterol-fed rats. Results :GCHD showed anti-oxidant activity in the study inhibiting the formation of 1-diphenyl-2-picrylhydrazyl radicals and xanthine oxidase activity. GCHD had anti-platelet aggregation activity. GCHD significantly lowered total cholesterol (TC), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) in high cholesterol diet and Triton WR-1339 induced model TG in corn oil-induced model. GCHD had no acute toxicity at a single dosage. Conclusion : These results suggest that GCHD has the potential to treat hyperlipidemia and stroke.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.4
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• pp.22-28
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• 2013

It is important to begin left ventricular assist device (LVAD) treatment at appropriate time for heart failure patients who expect cardiac recovery after the therapy. In order to predict the optimal timing of LVAD implantation, we predicted pumping efficacy of LVAD according to the severity of heart failure theoretically. We used LVAD-implanted cardiovascular system model which consist of 8 Windkessel compartments for the simulation study. The time-varying compliance theory was used to simulate ventricular pumping function in the model. The ventricular systolic dysfunction was implemented by increasing the end-systolic ventricular compliance. Using the mathematical model, we predicted cardiac responses such as left ventricular peak pressure, cardiac output, ejection fraction, and stroke work according to the severity of ventricular systolic dysfunction under the treatments of continuous and pulsatile LVAD. Left ventricular peak pressure, which indicates the ventricular loading condition, decreased maximally at the 1st level heart-failure under pulsatile LVAD therapy and 2nd level heart-failure under continuous LVAD therapy. We conclude that optimal timing for pulsatile LVAD treatment is 1st level heart-failure and for continuous LVAD treatment is 2nd level heart-failure when considering LVAD treatment as "bridge to recovery".

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1660-1664
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• 2008

Extra-corporeal Life Support System (ECLS) is the device used in emergency cases to substitute a extracorporeal circulation in open heart surgery, cardiac arrest or in acute cardiopulmonary failure. To obtain the effect of counter-pulsation on hemodynamic response in the ECLS quantitatively, we developed cardiovascular model which consists of 12 compartment model of heldt et al. and 3 compartment model of Schreiner et al. based on windkessel approximation. We compared coronary perfusion, arterial pulse pressure, cardiac output, and left ventricular pressure-volume diagram according to flow configuration such as counter-pulsation, copulsation, and continous flow. When counter-pulsation was applied, 5% higher coronary perfusion, 26% lower pulse pressure, and 2% higher cardiac output than copulsation condition were calculated. We conclude that counter-pulsation configuration in the ECLS is hemodynamically more stable than copulsation and influences the positive effect to recover ventricles.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.3893-3898
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• 2012

In previous studies we predicted future trends in cancer incidence for each prefecture in order to plan cancer control. Those predictions, however, did not take into account the characteristics of each prefecture. We therefore used the results of age-period-cohort analysis of incidence and mortality data of Osaka, and estimated the incidence and mortality of cancers at all sites and selected sites. The results reflect the characteristics of Osaka, which has and is expected to have large number of patients with liver cancer. We believe our results to be useful for planning and evaluating cancer control activities in Osaka. It would be worthwhile to base the estimation of cancer incidence and mortality in each prefecture on each population-based cancer registry.

• Journal of Preventive Medicine and Public Health
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• v.37 no.2
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• pp.120-126
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• 2004

Objectives : This study sought to examine relationships between alcohol drinking and cardiovascular disease mortality and all-cause mortality. Methods : From March 1985 through December 1999, 2,696 males and 3,595 females aged 55 or over as of 1985 were followed up for their mortality until 31 December 1999. We calculated the mortality risk ratios by level of alcohol consumption. Among the drinker, the level of alcohol consumption was calculated by the frequency of alcohol comsumption and the type of alcohol. Cox proportional hazard model was used to adjust for confounding factors. Results : Among males, compared to abstainer, heavy drinker had significantly higher mortality in all cause(Risk ratio=1.35), cardiovascular disease(Risk ratio=1.52) and cerebrovascular disease(Risk ratio =1.66). Although not significant, moderate drinker had lower ischemic heart disease mortality(Risk ratio =0.38). Among females, there was no statistically significant association between alcohol comsumption and mortality. Conclusion : The results of this study suggest that alcohol drinking has harmful effect on all-cause mortality, cardiovascular disease mortality and cerebrovascular disease mortality among males, especially in heavy drinker among males. Minimal evidence on protective effect for cardiovascular disease mortality in low or moderate drinker is observed.

• Journal of Chest Surgery
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• v.45 no.5
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• pp.316-319
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• 2012

Background: The standard operative treatment of primary spontaneous pneumothorax (PSP) is thoracoscopic wedge resection, but necessity of pleurodesis still remains controversial. Nevertheless, pleural procedure after wedge resection such as pleurodesis has been performed in some patients who need an extremely low recurrence rate. Materials and Methods: From January 2000 to July 2010, 207 patients who had undergone thoracoscopic wedge resection and pleurodesis were enrolled in this study. All patients were divided into two groups according to the methods of pleurodesis; apical parietal pleurectomy (group A) and pleural abrasion (group B). The recurrence after surgery had been checked by reviewing medical record through follow-up in ambulatory care clinic or calling to the patients, directly until January 2011. Results: Of the 207 patients, the recurrence rate of group A and B was 9.1% and 12.8%, respectively and there was a significant difference (p=0.01, Cox's proportional hazard model). There was no significant difference in age, gender, smoking status, and body mass index between two groups. Conclusion: This study suggests that the risk of recurrence after surgery in PSP is significantly low in patients who underwent thoracoscopic wedge resection with parietal pleurectomy than pleural abrasion.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.2
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• pp.103-111
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• 2019

The study is to investigate effects of andrographolide on experimental autoimmune myocarditis (EAM). Lewis rats were immunized on day 0 with porcine cardiac myosin to establish EAM. The EAM rats were treated with either andrographolide (25, 50, 100 mg/kg/day) or vehicle for 21 days. An antigen-specific splenocytes proliferation assay was performed by using the cells from control rats immunized with cardiac myosin. Survival rates, myocardial pathology and myocardial functional parameters (left ventricle end-diastolic pressure, ${\pm}dP/dt$ and left ventricular internal dimension) of EAM rats received andrographolide were significantly improved. Andrographolide treatment caused an decrease in the infiltration of $CD3^+$ and $CD14^+$ positive cells in myocardial tissue. Moreover, andrographolide treatment caused a reduction in the plasma levels of tumor necrosis factor-alpha, interleukin-17 (IL-17) and myosin-antibody, and an increase in the level of IL-10 in EAM rats. Oral administration of andrographolide resulted in the decreased expression of p-PI3K, p-Akt without any change of PI3K and Akt. Further results indicate andrographolide significantly inhibited myosin-induced proliferation in splenocytes, and this effect was inhibited by co-treatment of SC79 (Akt activator). Our data indicate andrographolide inhibits development of EAM, and this beneficial effect may be due to powerful anti-inflammatory activity and inhibitory effect on PI3K/Akt pathway.

• Journal of Chest Surgery
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• v.56 no.5
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• pp.304-310
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• 2023

Background: The late progression of tricuspid regurgitation (TR) after mitral valve surgery is well known. However, few reports have described the progression of TR after aortic valve surgery. We investigated the incidence of and risk factors for the development of significant TR after isolated aortic valve replacement (AVR). Methods: This study analyzed patients with less than moderate TR who underwent isolated AVR at Seoul National University Hospital from January 1990 to December 2018. Significant TR was defined as moderate or higher. Echocardiographic follow-up was performed in all patients. The Fine-Gray model was used to identify clinical risk factors for the development of significant TR. Results: In total, 583 patients (61.7±14.2 years old) were included. Operative mortality occurred in 9 patients (1.5%), and the overall survival rates at 10, 20, and 25 years were 91.1%, 83.2%, and 78.9%, respectively. Sixteen patients (2.7%) developed significant TR during the follow-up period (13 moderate; 3 severe). The cumulative incidence of significant TR at 10, 20, and 25 years was 0.77%, 3.83%, and 6.42%, respectively. No patients underwent reoperation or reintervention of the tricuspid valve. Hemodialysis or peritoneal dialysis for chronic kidney disease (hazard ratio [HR], 5.188; 95% confidence interval [CI], 1.154-23.322) and preoperative mild TR (HR, 5.919; 95% CI, 2.059-17.017) were associated with the development of significant TR in the multivariable analysis. Conclusion: TR progression after isolated AVR in patients with less than moderate TR is rare. Preoperative mild TR and hemodialysis or peritoneal dialysis for chronic kidney disease were significant risk factors for the development of TR.

• The Journal of Internal Korean Medicine
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• v.29 no.2
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• pp.413-420
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• 2008

Objective : To investigate the therapeutic effect of scalp acupuncture on dysarthria after stroke. Methods : A-B model in single subject research. The experimental group of 7 members received scalp acupuncture and the control group of 5 nothing for dysarthria itself. Five single vowels were recorded by voice recorder and measured for 1st & 2nd formant. By the formants, a vowel space was made according to each one of the patients. Praat program was used for evaluation. Results : 4 cases in the experimental group showed significant change and just 1 case of the none-operated group got better. Conclusion : In this study, it's proven that acupuncture treatment might have positive efficacy on dysarthria cases. At this moment, more clinical reports are needed for objective oriental medical study.