• Journal of Yeungnam Medical Science
• /
• v.16 no.2
• /
• pp.181-192
• /
• 1999

Background: Nitric oxide, a vasodilator synthesized from L-arginine by vascular endothelial cells, accounts for the biological activity of endothelium derived relaxing factor. Previous studies demonstrated that nitric oxide inhibitor, $N^{\omega}$-Nitro-L-Arginine(NNA) diminished the hyperdynamic splanchnic and systemic circulation in portal hypertensive rats The present study was done to determine the role of nitric oxide in the development of hyperdynamic circulations in the prehepatic portal hypertensive rat model produced by partial portal vein ligation. Methods: The portal hypertensive rats were divided into water ingestion group and NNA ingestion group. After partial portal vein ligation, NNA ingestion group and water ingestion group received NNA 1mg/kg/day and plain water through the mouth for 14 days, respectively. Cardiac output, mean arterial pressure, organ blood flow and porto-systemic shunting were measured by radioisotope labeled microsphere methods. Vascular resistances were calculated by standard equation. Results: There were significant decreases in mean arterial pressure, increases in cardiac output and cardiac index, and decreases in total systemic and splanchnic vascular resistance in portal hypertensive rats compared to normal control group (p<0.01). Compared to the water ingestion group, significantly increased mean arterial pressure with decreased cardiac output and cardiac index were developed in the NNA ingestion group. Total systemic and splanchnic vascular resistance were significantly increased in the NNA ingestion group compared to water ingestion group (p<0.05). But, there was no significant difference in portal pressure between the two groups. Conclusion: The hemodynamic results of this study indicate that hyperdynamic circulation in prehepatic portal hypertensive rat mode1 was attenuated by ingestion of NNA. Nitric oxide may play an important role in the development of hyperdynamic circulation with splanchnic vasodilation in chronic portal hypertension.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.18
• /
• pp.7849-7855
• /
• 2014

Purpose: To investigate the effect of deacetylase inhibitory trichostatin A (TSA) on anti HepG2 liver carcinoma cells and explore the underlying mechanisms. Materials and Methods: HepG2 cells exposed to different concentrations of TSA for 24, 48, or 72h were examined for cell growth inhibition using CCK8, changes in cell cycle distribution with flow cytometry, cell apoptosis with annexin V-FTIC/PI double staining, and cell morphology changes under an inverted microscope. Expression of ${\beta}$-catenin, HDAC1, HDAC3, H3K9, CyclinD1 and Bax proteins was tested by Western blotting. Gene expression for ${\beta}$-catenin, HDAC1and HDAC3 was tested by q-PCR. ${\beta}$-catenin and H3K9 proteins were also tested by immunofluorescence. Activity of Renilla luciferase (pTCF/LEF-luc) was assessed using the Luciferase Reporter Assay system reagent. The activity of total HDACs was detected with a HDACs colorimetric kit. Results: Exposure to TSA caused significant dose-and time-dependent inhibition of HepG2 cell proliferation (p<0.05) and resulted in increased cell percentages in G0/G1 and G2/M phases and decrease in the S phase. The apoptotic index in the control group was $6.22{\pm}0.25%$, which increased to $7.17{\pm}0.20%$ and $18.1{\pm}0.42%$ in the treatment group. Exposure to 250 and 500nmol/L TSA also caused cell morphology changes with numerous floating cells. Expression of ${\beta}$-catenin, H3K9and Bax proteins was significantly increased, expression levels of CyclinD1, HDAC1, HDAC3 were decreased. Expression of ${\beta}$-catenin at the genetic level was significantly increased, with no significant difference in HDAC1and HDAC3 genes. In the cytoplasm, expression of ${\beta}$-catenin fluorescence protein was not obvious changed and in the nucleus, small amounts of green fluorescence were observed. H3K9 fluorescence protein were increased. Expression levels of the transcription factor TCF werealso increased in HepG2 cells following induction by TSA, whikle the activity of total HDACs was decreased. Conclusions: TSA inhibits HDAC activity, promotes histone acetylation, and activates Wnt/${\beta}$-catenin signaling to inhibit proliferation of HepG2 cell, arrest cell cycling and induce apoptosis.

• Korea journal of population studies
• /
• v.12 no.2
• /
• pp.1-21
• /
• 1989

For the analysis of mortality differentials by socioeconomic factors based on death registration data, we have considered four variables : place of residence, educational attainment, marital status and occupation. The age range adopted were 5 to 64 years of age for place of residence, and 25 to 64 years of age for the other factors. The mortality differentials by socioeconomic variables were clear and in the expected direction: mortality levels among urban residents, better educated groups, and non- agricultural workers were lower than among the other sub- groups. The average mortality level in rural areas is much higher than in urban areas : the rural mortality levels were at least double the urban levels at ages below 40 years, but became smaller after age 40, and no clear differentials by urban I rural residence increased until 1974~76 for the both sexes, but since the then differentials have declined slowley for both sexes. This changing pattern of mortality differentials by place of residence can be explained by historical socioeconomic development : the development generally started in urban areas, and rural areas followed : in the course of socioeconomic development the differences between the death rates in the two areas became smaller and finally the mortality levels in the two areas became nearly the same, as is found in the developed countries nowadays. The inverse relationships between mortality and educational level became stronger between the periods 1970~72 and 1984~86, but showed the same atterns of mortality differentials in both period : larger differences among the younger age groups, and for males, than among the older age groups, and for females. The increasing mortality differentials in the fourteen-year period between 1970~72 and 1984~86 were caused by inadequate living standards of the non- educated, whose proportion in the total population, however, dropped sharply during that period. Also, the much lower proportions of low - educated groups or of persons with no formal education among males than females helped to establish the clearly pronounced differentials. The mortality differentials by marital status in Korea showed the usual pattern : the mortality rates of the married in each age and sex group were clearly lower than those of others during the fourteen-year period between 1970~72 and 1984~86. In Korean society which remotes universal marriage, the never married recorded especially high death rates, presumably mainly because of ill - health, but also possibly because of the stigma attached to celibacy. However, the mortality differentials by marital status changed with the changes in the proportionate distribution by marital status during the period : the differences between the death rates of the married and never married groups became smaller, the proportion of the never married group increased : in contrast, the differences between mortalities of the married and widowed / divorced / separated groups widened, with the decrease in the proportion of the later group ; this tendency was perticularly marked for females. Occupational groups also showed clear mortality differences : among four occupational groups mortality of males was highest among agricultural workers and lowest among 'professional, admi-nistrative and clerical workers, However, when the death rates were standardized by educational level, the death rates by occupation in age group 45~64 years were nearly the same (excet for the mixed group consisting of unemployed, students, military servicemen and unknown). Therefore, the clear mortality dfferentials by occupation in Korea resulted mainly from the differences in educational level between different occupation groups. Since socioeconomic characteristics are related to each other, the net effect of each variable was examined. Each of the three variables - ducational level, marital status and urban / rural residence affected significantly Korean adult mortality when the effects of the other variables were controlled. Among the three variables educational level was the most important factor for the determination of the adult mortality level. When male's occupation was added to the above three variables, the effects of occupation on adult mortality were notably smaller after control for the effects of the other three variables while the net effects of these three variables were nearly the same irrespectively whether occupation was included or not. Thus, the differences in educational level (mainly), place of residence and marital status bring out the clear differences in observed mortality levels by occupation.

• Korea journal of population studies
• /
• v.26 no.1
• /
• pp.31-57
• /
• 2003

This study is intended to examine (l)whether the value of son-for example, old age security and succession of family lineage- causing son preference in the traditional society can be explained at the individual level, (2)whether women without son in the son preference country continue her childbearing until having at least one son or give up the desire of having a son at a certain level. To accomplish these purposes, the 1974 Korean National Fertility Survey data are analyzed by the quadratic hazard models controlling unobserved heterogeneity. Unlike ordinary regression model, even omitted variables that affect hazard rates and are uncorrelated with the included independent variables can distort the parameter estimates in the hazard model. Therefore the nonparametric maximum likelihood estimator(NPMLE) of a mixing distribution developed by Heckman and Singer is used to control unobserved heterogeneity. Based on the statistical result in this study, the value of son causing son preference is determined at the societal level, not at the individual level. And Korean women without a son did not continue endlessly childbearing during child bearing ages until having a son. In general, they gave up the desire having a son when she had born six daughters continuously. Thus, 30-40 years ago, the number of daughters that women without a son giving up the desire of son was six, which is about the level of total fertility rate during 1960s. In these days, we can often see many women who have only two or three daughters and do not any son. This means that the level of giving up the desire of son, which is one factor representing the strength of son preference, becomes lower. If the strength of son preference did not become much weaker, then the fertility rates in Korea could not reach the below replacement level.

• Journal of Embryo Transfer
• /
• v.19 no.3
• /
• pp.245-255
• /
• 2004

In recent years, an increasing number of studies on pig in vitro maturation(IVM) and in vitro fertilization(IVF) have been separated. the wide range of new technologies, including that in applied molecular genetics, has increased this interest. the production of viable porcine embryos in vitro is a prerequisites for the successful production of transgenic pigs to date. The efficiency of IVM/IVF techniques in the porcine is lower than that obtained in other species such as cattle and mouse. The several problems are generally thought to be the cause of poor results: the low rate of MPN formation derived from inadequate IVM of oocytes, the high incidence of polyspermy after IVF and cell blocking at 4 cell during embryos culture. For there reasons overcoming, many studies have been conducted to improve in vitro embryo-genic competence of oocytes. In the last several years, many maturation culture media have been evaluated and various exogenous factors such as hormones and grows factors have been tested to improve the efficiency of porcine in vitro system. In the study several antioxidants have been examined to improve in vitro fertilization and development of porcine oocytes. In this study, several antioxidants were examined to determine the effects on the development of oocytes to the cleavage, morula and blastocyst stage when added at the maturation(IVM) or in vitro fertilization(IVF) or in vitro culture(IVC) of porcine embryos. Porcine oocytes were matured, fertilized and embryos were cultured in defind conditioned medium in vitro with or without supplementation with the antioxidents of cysteine, catalase and glutathione. 1. Significant improvement of blastocyst rate (27.2％ versus 15.4％, p<0.05) were achieved when catalase(500U/$m\ell$) were added to TCM-199 medium and morula rate(72.0％ versus 53.9％, p<0.05) were significantly higher when glutathione(1.0mM/$m\ell$) were added to TCM-199 medium than those of control. 2. In mTBM medium for oocytes fertilization, the addition of cysteine, catalase and glutathione had no positive effect on embryonic development. glutathione had no positive effect on embryonic development. In conclusion, this study shows that addition of catalase, gluththione during IVM improved the rate of porcine embryo development.

• Radiation Oncology Journal
• /
• v.15 no.3
• /
• pp.175-186
• /
• 1997

Purpose : To evaluate the qualitative immunologic changes by ionizing radiation. we studied the altered capacities of the macrophages and lymphocytes to produce cytokines in conjunction with resistance to Listeria monocytegenes (LM) infection in mice Materials and Methods : BALB/c mice and Listeria monocytogenes were used. The mice were infected intraperitoneally with $10^5LM$ at 1 day after irradiation (300cGy) and sacrificed at 1, 3, 5 days after infection, and then the numbers of viable LM per spleen in the irradiated and control group were counted. Tumor necrosis factor-alpha ($TNF-\alpha$), interferon-gamma ($IFN-\gamma$). interleukin-2 (IL-2), and nitric oxide (NO) were assessed after irradiation. Results : Under gamma-ray irradiation with a dose range of 100-850cGy, the number of total splenocytes decreased markedly in a dose-dependent manner, while peritoneal macrophages did so slightly Cultured peritoneal macrophages produced more $TNF-\alpha$ in the presence of lipopolysaccharide (LPS) during the 24 hours after in vitro irradiation, but their capacity of $TNF-\alpha$ Production showed a decreased tendency at 5 days after in vivo total body irradiation. With 100cGy and 300cGy irradiation, cultured peritoneal macrophages produced more NO in the presence of LPS during the 24 hours after in vitro irradiation than without irradiation. Activated splenocytes from irradiated mice (300cGy) exhibited a decreased capacity to Produce IL-2 and $IFN-\gamma$ with Concavalin-A stimulation at 3 days after irradiation. When BALB/c mice were irradiated to the total body with a dose of 300cGy, they showed enhanced resistance during early innate phase, but a significant inhibition of resistance to LM was found in the late innate and acquired T-cell dependent phases. Conclusion : These results su99es1 that increased early innate and decreased late innate and acquired immunity to LM infection by ionizing radiation (300cGy) may be related to the biphasic altered capacity of the macrophages to produce $TNF-\alpha$ and the decreased capacities of the lymphocytes to produce IL-2 and $IFN-\gamma$ in addition to a marked decrease in the total number of cells.

• Radiation Oncology Journal
• /
• v.28 no.3
• /
• pp.117-124
• /
• 2010

Purpose: To analyze the postoperative radiotherapy results and prognostic factors in patients with WHO grade 3 and 4 gliomas. Materials and Methods: A total of 99 patients with malignant gliomas who underwent postoperative radiotherapy between 1988 and 2007 were enrolled in this study. Total resections, subtotal resections ($\geq$50%), partial resections (<50%), and biopsies were performed in 16, 38, 22, and 23 patients, respectively. In total there were 32, 63 and 4 WHO grade 3, 4, and unspecified high grade gliomas, respectively. The biologically equivalent dose was in the range of 18.6 to $83.3\;Gy_{10}$ (median dose, $72.2\;Gy_{10}$). We retrospectively analyzed survival rate, patterns of failure, prognostic factors, and adverse effects. Results: The median follow-up time was 11 months and there were 54 patients (54.5%) with local failure. The one and 2-year survival rates were 56.6% and 29.3%, respectively, and the median survival duration was 13 months. The one and 2-year progression-free survival rates (PFS) were 31.3% and 18.2%, respectively, and the median PFS was 7 months. The prognostic factors for overall survival were age (p=0.0001), surgical extents (subtotal resection, p=0.023; partial resection, p=0.009; biopsy only, p=0.002), and enhancement of tumor in postoperative imaging study (p=0.049). The factors affecting PFS were age (p=0.036), tumor enhancement of the postoperative imaging study (p=0.006). There were 3 patients with grade 3 and 4 side effects during and after radiotherapy. Conclusions: In addition to age and surgical extents, tumor enhancement of the postoperative imaging study was included in the prognostic factors. The most common relapse patterns were local failures and hence, additional studies are needed to improve local control rates.

• Korean Journal of Soil Science and Fertilizer
• /
• v.37 no.4
• /
• pp.220-227
• /
• 2004

Phosphorus desorption study is essential to understanding P behavior in agricultural and environmental soils because phosphorus is considered as two different aspects, a plant nutrient versus an environmental contaminant. This study was conducted to determine soil P buffering power related to P desorption quantity intensity (Q/I) parameters, $Q_{max}$(an index of P release capacity) and $l_0$(an index of the intensity factor), and to investigate the characteristics of relationship between the P desorption Q/I parameters and the soil properties. Soil samples were prepared with treatments of 0 and $100mg\;P\;kg^{-1}$ applied as $KH_2PO_4$ solution. The P desorption Q/I curves were obtained by a procedure using anion exchange resin beads and described by an empirical equation ($Q=aI^{-1}+bln(I+1)+c$). The P desorption Q/I curves for the high available P (${\g}20mg\;kg^{-1}$ of Olsen P) soils were characteristic concave trends with or without soil P enrichment, whereas for the low available P (${\lt}20mg\;kg^{-1}$ of Olsen P) soils, the anticipated Q/I concave curves could not be obtained without a proper amount of P addition. When the soils were enriched in phosphates, the values of desorbed solid phase labile P and solution P, such as $Q_{max}$ and $I_0$ respectively, were increased, but the ratio of $Q_{max}$ versus $I_0$ was decreased. Thus, the slope of desorption Q/I curve represented as phosphorus buffering power, $|BP_0|$, is decreased. The $|BP_0|$ values of the high available P soils ranged between 48 and $61L\;kg^{-1}$ in the P untreated samples and between 18 and $44L\;kg^{-1}$ in the P enriched samples. Overall $|BP_0|$ values of both low and high available P soils treated with $l00mg\;P\;kg^{-1}$ ranged between 14 and $79L\;kg^{-1}$. The $Q_{max}$, values ranged between 71.4 and $173.1mg\;P\;kg^{-1}$, and the lo values ranged between 0.98 and $3.82mg\;P\;L^{-1}$ in the P enriched soils. The $Q_{max}$ and $I_0$ values that control the P buffering power may be not specifically related to a specific soil property, but those values were complicatedly related to soil pH, clay content, soil organic matter content, and lime. Also, phosphorus release activity, however, markedly depended on the desorbability of the applied P as well as the native labile P.

• Journal of Chest Surgery
• /
• v.31 no.2
• /
• pp.125-133
• /
• 1998

This study was designed to identify the efficiency of serum troponin-T(s-TnT) level as a diagnostic indicator for the perioperative myocardial damage with open heart surgery(OHS) and to compare with the conventional myocardial enzyme tests such as isoenzyme fraction of creatine kinase(% CK-MB) and isoenzyme ratio of lactate dehydrogenase(LDH1/LDH2 ratio). The study was performed on 30 adult patients who underwent OHS from Jan. 1996 to June 1996 at Inje University Pusan Paik Hospital, and they were divided into two groups accor- ding to aortic clamping time(ACT) duration : group I(ACT＜60 minutes, n=15); group II (ACT＞60 minutes, n=15). S-TnT, % CK-MB, and LDH1/LDH2 ratio were measured in serial blood samples from all subjected patients. The results were obtained as follows. 1. In both groups, s-TnT concentrations increased gradually during OHS and elevated significantly at CPB-10(p＜0.001). The peak level was noticed at POD 1 in group I(1.10 $\pm$0.19 ng/ml), whereas, at CPB-off in group II(1.88$\pm$0.42 ng/ml). The elevated levels remained until POD 7 in both groups. 2. %CK-MB was risen significantly with the initiation of operations(p＜0.001) and the peak levels were noticed at CPB-off in both groups(7.14$\pm$0.86% in group I, 10.69$\pm$1.27% in group II). Thereafter, these levels returned to normal values at POD 3. 3. There were no significant changes in the values of LDH1/LDH2 ratio during and after OHS compared with the control levels(p＞0.05). 4. The serial changes of s-TnT were relatively well correlated with those of changes of % CK-MB(r=0.64, p＜0.05). 5. The serial s-TnT levels were significantly higher in group II than group I from B-ACR to POD 1(p＜0.05), suggesting that duration of aortic clamping time was a major factor concerned with perioperative myocardial injury. In conclusion, measurement of s-TnT is a very useful indicator in assessing the myocardial cell damage and therefore it is expected that serial checking and evaluation of the s-TnT is very available for identification of the perioperative myocardial damage and for postoperative cares in patients with OHS.

• Asia pacific journal of information systems
• /
• v.19 no.2
• /
• pp.157-178
• /
• 2009

Corporate credit rating is a very important factor in the market for corporate debt. Information concerning corporate operations is often disseminated to market participants through the changes in credit ratings that are published by professional rating agencies, such as Standard and Poor's (S&P) and Moody's Investor Service. Since these agencies generally require a large fee for the service, and the periodically provided ratings sometimes do not reflect the default risk of the company at the time, it may be advantageous for bond-market participants to be able to classify credit ratings before the agencies actually publish them. As a result, it is very important for companies (especially, financial companies) to develop a proper model of credit rating. From a technical perspective, the credit rating constitutes a typical, multiclass, classification problem because rating agencies generally have ten or more categories of ratings. For example, S&P's ratings range from AAA for the highest-quality bonds to D for the lowest-quality bonds. The professional rating agencies emphasize the importance of analysts' subjective judgments in the determination of credit ratings. However, in practice, a mathematical model that uses the financial variables of companies plays an important role in determining credit ratings, since it is convenient to apply and cost efficient. These financial variables include the ratios that represent a company's leverage status, liquidity status, and profitability status. Several statistical and artificial intelligence (AI) techniques have been applied as tools for predicting credit ratings. Among them, artificial neural networks are most prevalent in the area of finance because of their broad applicability to many business problems and their preeminent ability to adapt. However, artificial neural networks also have many defects, including the difficulty in determining the values of the control parameters and the number of processing elements in the layer as well as the risk of over-fitting. Of late, because of their robustness and high accuracy, support vector machines (SVMs) have become popular as a solution for problems with generating accurate prediction. An SVM's solution may be globally optimal because SVMs seek to minimize structural risk. On the other hand, artificial neural network models may tend to find locally optimal solutions because they seek to minimize empirical risk. In addition, no parameters need to be tuned in SVMs, barring the upper bound for non-separable cases in linear SVMs. Since SVMs were originally devised for binary classification, however they are not intrinsically geared for multiclass classifications as in credit ratings. Thus, researchers have tried to extend the original SVM to multiclass classification. Hitherto, a variety of techniques to extend standard SVMs to multiclass SVMs (MSVMs) has been proposed in the literature Only a few types of MSVM are, however, tested using prior studies that apply MSVMs to credit ratings studies. In this study, we examined six different techniques of MSVMs: (1) One-Against-One, (2) One-Against-AIL (3) DAGSVM, (4) ECOC, (5) Method of Weston and Watkins, and (6) Method of Crammer and Singer. In addition, we examined the prediction accuracy of some modified version of conventional MSVM techniques. To find the most appropriate technique of MSVMs for corporate bond rating, we applied all the techniques of MSVMs to a real-world case of credit rating in Korea. The best application is in corporate bond rating, which is the most frequently studied area of credit rating for specific debt issues or other financial obligations. For our study the research data were collected from National Information and Credit Evaluation, Inc., a major bond-rating company in Korea. The data set is comprised of the bond-ratings for the year 2002 and various financial variables for 1,295 companies from the manufacturing industry in Korea. We compared the results of these techniques with one another, and with those of traditional methods for credit ratings, such as multiple discriminant analysis (MDA), multinomial logistic regression (MLOGIT), and artificial neural networks (ANNs). As a result, we found that DAGSVM with an ordered list was the best approach for the prediction of bond rating. In addition, we found that the modified version of ECOC approach can yield higher prediction accuracy for the cases showing clear patterns.