• Journal of Chest Surgery
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• v.25 no.8
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• pp.863-870
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• 1992

The low profile Ionescu-Shiley pericardial xenograft valve had been initially introduced to have improved hemodynamic performance and expected superior durability, However, subsequent clinical reports and laboratory studies have repeatedly indicated early failure of the valve from mechanical reasons in valve design, A total and consecutive 169 patients underwent isolated MVR with the low profile Ionescu-Shiley valve at Seoul National University Hospital from November 1984 to October 1989 [Group ISLM]. Five patients [3.0%] died within 30 days of surgery, and early survivors were followed up for 734.9 patient-years [Mean$\pm$SD, 4.9$\pm$2.0 years], Late mortality rate was 0.136% /patient-year [pt-yr], Linearized incidences of major complications were: 0.953% embolism /pt-yr; 0.680% bleeding /pt-yr; 0.272% endocarditis /pt-yr; and 0, 408% primary tissue failure [PTF] /pt-yr, The actuarial survival was 99.4$\pm$0.6%, and probabilities of from thromboembolism and from PTF were 90.7$\pm$4.6% and 95.9$\pm$2.6% at 8 years, respectively These results were compared with the clinical data from the 291 patients of isolated MVR with the standard Ionescu-Shiley valve at the same hospital during the period between October 1978 and June 1983 [Group ISUM], Group ISUM included 11% of patients younger than 15 years of age, whereas Group ISLM did no patient of this age. The mean age at the time of surgery was significantly younger in Group ISUM than one in Group ISLM [P<0.001]. Differences were not statistically significant in operative mortality, mean follow-up period and linearized incidences of thromboembolism, bleeding and endocarditis, between two groups, However, the linearized rate of PTF was lower [P<0.001] and probabilities of freedom fro PTF higher [P<0.001] in Group ISLM at least up to postoperative 8 years. While the features of PTF of the standard valve was predominantly degeneration with calcification and stenosis, the ones of the low profile valve was cusp tear and incompetence. It remains, however, to be seen whether the low profile valve fails mostly from mechanical reason, and further follow-up will still be necessary to determine the differences in mode of PTF of two valves.

• Journal of Oral Medicine and Pain
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• v.34 no.3
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• pp.257-260
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• 2009

Gingival hyperpigmentation may cause esthetic problems, especially in patients with a gummy smile. This report presents the use of the $CO_2$ laser for gingival depigmentation. Two cases presented with the same chief complaint of unesthetic gingiva caused by melanin hyperpigmentation. The $CO_2$ laser was setted at 0.8 watt, 40Hz, 0.01sec. The procedure were performed with non-contact mode in all pigmented areas. Ablation of the gingival hyperpigmentation areas were accomplished without any bleeding complications or postoperative pain. After 2 weeks and 4 weeks later, healing is completed and hyperpigmented gingiva appeared pink and firm.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1212-1220
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• 2013

The human coagulation factor XI (FXI) is a serine protease that plays a significant role in blocking of the blood coagulation cascade as an attractive antithrombotic target. Selective inhibition of FXIa (an activated form of factor XI) disrupts the intrinsic coagulation pathway without affecting the extrinsic pathway or other coagulation factors such as FXa, FIIa, FVIIa. Furthermore, targeting the FXIa might significantly reduce the bleeding side effects and improve the safety index. This paper reports on a docking-based three dimensional quantitative structure activity relationship (3D-QSAR) study of the potent FXIa inhibitors, the chloro-phenyl tetrazole scaffold series, using comparative molecular field analysis (CoMFA) and comparative molecular similarity analysis (CoMSIA) methods. Due to the characterization of FXIa binding site, we classified the alignment of the known FXIa inhibitors into two groups according to the docked pose: S1-S2-S4 and S1-S1'-S2'. Consequently, highly predictive 3D-QSAR models of our result will provide insight for designing new potent FXIa inhibitors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1169-1176
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• 2010

The RF front-end for L1/L2 dual-band Global Positioning System(GPS) receiver is presented in this paper. The RF front-end(down-converter) using low IF architecture consists of a wideband low noise amplifier(LNA), a current mode logic(CML) frequency divider and a I/Q down-conversion mixer with a poly-phase filter for image rejection. The current bleeding technique is used in the LNA and mixer to obtain the high gain and solve the head-room problem. The common drain feedback is adopted for low noise amplifier to achieve the wideband input matching without inductors. The fabricated RF front-end using $0.18{\mu}m$ CMOS process shows a gain of 38 dB for L1 and 41 dB for L2 band. The measured IIP3 is -29 dBm in L1 band and -33 dBm in L2 band, The input return loss is less than -10 dB from 50 MHz to 3 GHz. The measured noise figure(NF) is 3.81 dB for L1 band and 3.71 dB for L2 band. The image rejection ratio is 36.5 dB. The chip size of RF front end is $1.2{\times}1.35mm^2$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.443-451
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• 2010

This paper describes a fully integrated CMOS low-IF mobile-TV RF tuner for Band-III T-DMB/DAB applications. All functional blocks such as low noise amplifier, mixers, variable gain amplifiers, channel filter, phase locked loop, voltage controlled oscillator and PLL loop filter are integrated. The gain of LNA can be controlled from -10 dB to +15 dB with 4-step resolutions. This provides a high signal-to-noise ratio and high linearity performance at a certain power level of RF input because LNA has a small gain variance. For further improving the linearity and noise performance we have proposed the RF VGA exploiting Schmoock's technique and the mixer with current bleeding, which injects directly the charges to the transconductance stage. The chip is fabricated in a 0.18 um mixed signal CMOS process. The measured gain range of the receiver is -25~+88 dB, the overall noise figure(NF) is 4.02~5.13 dB over the whole T-DMB band of 174~240 MHz, and the measured IIP3 is +2.3 dBm at low gain mode. The tuner rejects the image signal over maximum 63.4 dB. The power consumption is 54 mW at 1.8 V supply voltage. The chip area is $3.0{\times}2.5mm^2$.

• Journal of Chest Surgery
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• v.18 no.4
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• pp.679-691
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• 1985

Ninety patients underwent mitral valvular heart surgery associated with or without aortic valve surgery and subjected to a clinical study in relation to their control of postoperative atrial fibrillation. There were 26 males and 64 females ranged in age from 16 to 56 years with a mean of 35.2 years. Systemic arterial embolizations were observed in 11 patients [12.2%]. Four patients of them were in normal sinus rhythm and 7 in atrial fibrillation. Out of these, left atrial thrombi were found only in 2 at the operation. Intraoperatively confirmed left atrial thrombi were in 16 patients [17.7%] of all 90 patients: Eleven patients occurred at the age of more than 40 years, 14 were in atrial fibrillation and 2 only had previous episodes of systemic arterial embolization. Sixty three patients underwent isolated mitral valve surgery [OMC 28, MVR 35] and 27 patients associated with aortic valve surgery along with mitral valve [OMC+AVR 13, MVR+AVR 14]. Preoperatively, 44 patients [48.9%] were in normal sinus rhythm. Of them, 35 patients [79.5%] revealed normal sinus rhythm thoroughly after operation without any aid of digitalis or quinidine and 5 patients [11.4%] restored normal sinus rhythm with digitalization alone. Other 3 patients converted to normal sinus rhythm with the addition of quinidine, however, in 1 patient who was resistant to quinidine therapy, electrocardioversion was carried out on the postoperative third week showing normal sinus rhythm. Thus, the most atrial fibrillations that occurred for the first time in the postoperative period, were able to reverted to normal sinus rhythm responding well to antiarrhythmic therapy. Preoperatively, 46 patients [51.1%] were in atrial fibrillation. Of them, only 5 patients returned to sinus rhythm after operation without any aid of digitalis or quinidine and other 5 restored normal sinus rhythm with digitalization: namely 2 restored within early postoperative period and 3 after more than 3 months. Eight patients well responded to quinidine therapy showing normal Sinus rhythm. So far, 25 patients have remained in persistent atrial fibrillation on 6 to 36 months follow-up. In view of these, 17 patients [68%] were over 40 years of age, 22[80%] had long duration of symptom over 5 years and 10[40%] have had atrial thrombi before operation. Left atrial dimension were still more than 40mm in 21 patients on follow up M-mode echocardiogram. One month after operation, 87 hospital survivors were improved by at least one functional NYHA class. There were 3 operative deaths [3.3%, bleeding 1, LCOS 2] and 4 late deaths [LCOS 1, valve thrombosis 1, late bleeding 1, fulminant hepatitis 1] during follow-up period. According to our limited experience, we may conclude that better results will be expected with the addition of quinidine therapy judiciously in the cases of postoperative persistent atrial fibrillation who were aged or had longer history of symptom and left atrial thrombi.

• Korean Circulation Journal
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• v.54 no.2
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• pp.63-75
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• 2024

Background and Objectives: Evidence regarding the efficacy and safety of intracardiac echocardiography (ICE) for guidance during transcatheter aortic valve replacement (TAVR) is limited. This study aimed to compare the clinical efficacy and safety of ICE versus transesophageal echocardiography (TEE) for guiding TAVR. Methods: This prospective cohort study included patients who underwent TAVR from August 18, 2015, to June 31, 2021. Eligible patients were stratified by echocardiographic modality (ICE or TEE) and anesthesia mode (monitored anesthesia care [MAC] or general anesthesia [GA]). Primary outcome was the 1-year composite of all-cause mortality, rehospitalization for cardiovascular cause, or stroke, according to the Valve Academic Research Consortium-3 (VARC-3) definition. Propensity score matching was performed, and study outcomes were analyzed for the matched cohorts. Results: Of the 359 eligible patients, 120 patients were matched for the ICE-MAC and TEEGA groups, respectively. The incidence of primary outcome was similar between matched groups (18.3% vs. 20.0%; adjusted hazard ratio, 0.94; 95% confidence interval [CI], 0.53-1.68; p=0.843). ICE-MAC and TEE-GA also had similar incidences of moderate-to-severe paravalvular regurgitation (PVR) (4.2% vs. 5.0%; adjusted odds ratio, 0.83; 95% CI, 0.23-2.82; p=0.758), new permanent pacemaker implantation, and VARC-3 types 2-4 bleeding. Conclusions: ICE was comparable to TEE for guidance during TAVR for the composite clinical efficacy outcome, with similar incidences of moderate-to-severe PVR, new permanent pacemaker implantation, and major bleeding. These results suggest that ICE could be a safe and effective alternative echocardiographic modality to TEE for guiding TAVR.

• Molecules and Cells
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• v.43 no.11
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• pp.964-973
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• 2020

Recent studies have highlighted that early enhancement of the glycolytic pathway is a mode of maintaining the proinflammatory status of immune cells. Thiamine, a wellknown co-activator of pyruvate dehydrogenase complex, a gatekeeping enzyme, shifts energy utilization of glucose from glycolysis to oxidative phosphorylation. Thus, we hypothesized that thiamine may modulate inflammation by alleviating metabolic shifts during immune cell activation. First, using allithiamine, which showed the most potent anti-inflammatory capacity among thiamine derivatives, we confirmed the inhibitory effects of allithiamine on the lipopolysaccharide (LPS)-induced pro-inflammatory cytokine production and maturation process in dendritic cells. We applied the LPS-induced sepsis model to examine whether allithiamine has a protective role in hyper-inflammatory status. We observed that allithiamine attenuated tissue damage and organ dysfunction during endotoxemia, even when the treatment was given after the early cytokine release. We assessed the changes in glucose metabolites during LPS-induced dendritic cell activation and found that allithiamine significantly inhibited glucose-driven citrate accumulation. We then examined the clinical implication of regulating metabolites during sepsis by performing a tail bleeding assay upon allithiamine treatment, which expands its capacity to hamper the coagulation process. Finally, we confirmed that the role of allithiamine in metabolic regulation is critical in exerting anti-inflammatory action by demonstrating its inhibitory effect upon mitochondrial citrate transporter activity. In conclusion, thiamine could be used as an alternative approach for controlling the immune response in patients with sepsis.

• Journal of Preventive Medicine and Public Health
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• v.38 no.2
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• pp.132-140
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• 2005

Objectives: To propose a risk-adjustment model from insurance claims data, and analyze the changes in cesarean section rates of healthcare organizations after adjusting for risk distribution. Methods: The study sample included delivery claims data from January to September, 2003. A risk-adjustment model was built using the 1st quarter data, and the 2nd and 3rd quarter data were used for a validation test. Patients' risk factors were adjusted using a logistic regression analysis. The c-statistic and Hosmer-Lemeshow test were used to evaluate the performance of the risk-adjustment model. Crude, predicted and risk-adjusted rates were calculated, and compared to analyze the effects of the adjustment. Results: Nine risk factors (malpresentation, eclampsia, malignancy, multiple pregnancies, problems in the placenta, previous Cesarean section, older mothers, bleeding and diabetes) were included in the final risk-adjustment model, and were found to have statistically significant effects on the mode of delivery. The c-statistic (0.78) and Hosmer-Lemeshow test ($x^2$=0.60, p=0.439) indicated a good model performance. After applying the 2nd and 3rd quarter data to the model, there were no differences in the c-statistic and Hosmer-Lemeshow $x^2$. Also, risk factor adjustment led to changes in the ranking of hospital Cesarean section rates, especially in tertiary and general hospitals. Conclusion: This study showed a model performance, using medical record abstracted data, was comparable to the results of previous studies. Insurance claims data can be used for identifying areas where risk factors should be adjusted. The changes in the ranking of hospital Cesarean section rates implied that crude rates can mislead people and therefore, the risk should be adjusted before the rates are released to the public. The proposed risk-adjustment model can be applied for the fair comparisons of the rates between hospitals.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.2211-2215
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• 2016

The purpose of this study was to evaluate the prevalence and predictors of post-Loop Electrosurgical Excision Procedure (LEEP) complications in Srinagarind Hospital, Khon Kaen, Thailand. Retrospective chart review was performed for 200 patients undergoing LEEP during January 2012 to February 2013. Their mean age was 45 years-old. Fifty-three (26.5%) were menopausal. The three most common preceding abnormal cervical cytology were high-grade squamous intraepithelial lesion (HSIL; 50%), atypical squamous cell cannot exclude HSIL (ASC-H; 10.5%), and low-grade squamous intraepithelial lesion (LSIL; 10%). The overall complications prevalence rate was 16.5% (95%CI, 11.4-21.6). Complications included bleeding (11%; 95%CI, 6.66-15.3), offensive discharge (4%; 95%CI, 1.28-6.72), and pelvic inflammatory disease (1.5%; 95%CI, 0.18-3.18). Only mode of delivery was an independent predictor of post-LEEP complications. Women with previous caesarean sections carried an increased risk of complications by 3.9 times (95%CI, 1.21-12.56) compared with vaginal delivery. In conclusion, LEEP is generally safe with an acceptable complication rate. Previous caesarean section was the only independent predictor for post-LEEP complications. However, this predictor still needs prudent evaluation as no clear cause-effect relationship was identified.