• Journal of Oral Medicine and Pain
• /
• v.34 no.3
• /
• pp.261-276
• /
• 2009

Lactacystin, a microbial natural product synthesized by Streptomyces, has been commonly used as a selective proteasome inhibitor in many studies. Proteasome inhibitors is known to be preventing the proliferation of cancer cells in vivo as well as in vitro. Furthermore, proteasome inhibitors, as single or combined with other anticancer agents, are suggested as a new class of potential anticancer agents. This study was undertaken to examine in vitro effects of cytotoxicity and growth inhibition, and the molecular mechanism underlying induction of apoptosis in SCC25 human tongue sqaumous cell carcinoma cell line treated with lactacystin. The viability of SCC25 cells, human normal keratinocytes (HaCaT cells) and human gingiva fibroblasts (HGF-1 cells), and the growth inhibition of SCC25 cells were assessed by MTT assay and clonogenic assay respectively. The hoechst staining, hemacolor staining and TUNEL staining were conducted to observe SCC25 cells undergoing apoptosis. SCC25 cells were treated with lactacystin, and Western blotting, immunocytochemistry, confocal microscopy, FAScan flow cytometry, MMP activity, and proteasome activity were performed. Lactacystin treatment of SCC25 cells resulted in a time- and does-dependent decrease of cell viability and a does-dependent inhibition of cell growth, and induced apoptotic cell death. Interestingly, lactacytin remarkably revealed cytotoxicity in SCC25 cells but not normal cells. And tested SCC25 cells showed several lines of apoptotic manifestation such as nuclear condensation, DNA fragmentation, the reduction of MMP and proteasome activity, the decrease of DNA contents, the release of cytochrome c into cytosol, the translocation of AIF and DFF40 (CAD) onto nuclei, the up-regulation of Bax, and the activation of caspase-7, caspase-3, PARP, lamin A/C and DFF45 (ICAD). Flow cytometric analysis revealed that lactacystin resulted in G1 arrest in cell cycle progression which was associated with up-regulation in the protein expression of CDK inhibitors, $p21^{WAF1/CIP1}$ and $p27^{KIP1}$. We presented data indicating that lactacystin induces G1 cell cycle arrest and apoptois via proteasome, mitochondria and caspase pathway in SCC25 cells. Therefore our data provide the possibility that lactacystin could be as a novel therapeutic strategy for human tongue squamous cell carcinoma.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.31 no.2
• /
• pp.202-211
• /
• 2004

Xylitol is a 5-carbons carbohydrate, which can be replaced with sucrose for preventing dental caries. To study the effect of xylitol on the fermentation of lactose in bacteria, the important oral bacteria such as Streptococcus(S.) mutans, S. oralis and S. salivarius were studied. The optical density using spectophotometer and the cell concentration were assessed to evaluate the combined effect of lactose and xylitol against the bacteria. Thin layer chromatography and lactose-PTS activity test were performed to evaluate the effect of xylitol on the fermentation of lactose in S. mutans and by ${\beta}-galactosidase$ with the following results. 1. The optical density of Streptococcus mutans culture was not increased for 8 hours-incubation in the media added with lactose and xylitol, but was increased at 24 hours-incubation. The number of viable cells at 8 hours-incubation was smaller in the media containing lactose and xylitol in comparison with lactose only. 2. The optical densities of Streptococcus oralis culture and Streptococcus salivarius culture were not increased for 8 hours-incubation in the media added with lactose and xylitol but were increased at 24 hours-incubation. 3. When Streptococcus mutars was incubated for 8 hours in the media added with lactose and xylitol, the amount of remained lactose was larger compared with the media added with lactose only But all lactose was fermented in both media after 24 hours-incubation. 4. When Streptococcus mutans was incubated in the media added with lactose and xylitol, the activity of lactose-PTS was higher compared with the media added with lactose only. 5. When ${\beta}-galactosidase$ was incubated in the media added with lactose and xylitol, the amount of remained lactose was larger compared with the media added with lactose only. These results indicated that xylitol inhibited the fermentation of lactose by Streptococcus.

• Tuberculosis and Respiratory Diseases
• /
• v.46 no.6
• /
• pp.775-785
• /
• 1999

Background : The herbicide paraquat can cause severe lung injury and fibrosis in experimental animals. In this study we have investigated the changes in lung endothelin-1(Et-1) levels and immunohistochemical localization in relation to treatment with cyclophosphamide and methylprednisolone in paraquat induced pulmonary fibrosis in guinea pigs. Material and methods : 29 male Hartley guinea pigs were divided into 4 groups. Group I was normal control. Paraquat was instilled into the lung of guinea pig of group II, III and IV unilaterally. Group II was treated with cyclophosphamide and methylprednisolone. Group III was treated with methlprednisolone. Group IV was not treated. The degree of fibrosis was evaluated by H-E stains and Masson's trichrome stains and cell activity was assessed by Et-1 immunohistochemical stains. Statistical evaluation was performed using the Kruskawallis oneway analysis. Results : Paraquat induced an increase in numbers of fibroblasts and total amount of lung collagen in Group IV compared to the normal controls. There was no significant difference in total numbers of fibroblasts between any of paraquat instilled groups, but there was significant increase in total amount of collagen in Group IV compared to group II and III (p<0.05). The treatment of cyclophosphamide and methyprednisolone suppressed the growths of both fibroblasts and collagen, but this suppression was stastically significant only in the case of collagen Et-1 immunoreactivities of bronchial epithelium, type II pneumocytes, endothelial cells and fibroblast in group II and III were decreased compared to those in group IV. Conclusion : These results demonstrate that Et-1 is an important contributing factor in the pathogenesis of pulmonary fibrosis. Et-1 is synthesized and released by bronchial epithelium, Type II pneumocyte, endothelial cells, alveolar macrophages and fibroblasts. Especially they are associated with alveolar macrophage and fibroblasts. We conclude that combined therapy of cyclophosphamide and methylprednisolone are more effective in the control of Et-1 expression and collagen deposition.

• Journal of the Korean Electrochemical Society
• /
• v.10 no.1
• /
• pp.25-30
• /
• 2007

Proton exchange membrane fuel cell(PEMFC) performance could be affected by various factors such as cell temperature, total pressure, partial pressure of reactants and relative humidity. Hydrogen ion is combined with water to form hydronium ion [$H_3O^+$] and pass through membrane resulting electricity generation. Cooling system is needed to remove heat and other uses on large scale fuel cell. In case that collant conductivity is increased, fuel cell performance could be decreased because produced electricity could be leaked through coolant. In this study, triple distilled water(TDW) and antifreeze solution containing ethylene glycol was used to observe resistance change. Resistance of TDW was taken 28 days to reach preset value, and effect on fuel cell operation was not observed. Resistance of antifreeze solution was not reached to preset value up to 48 days, but performance failure occurred presumably caused by bipolar plate junction resulting stoppage resistance experiment. Generally PEMFC humidification is performed near-saturated operating conditions at various temperatures and pressures, but non-humidifying condition could be applied in small scale fuel cell to improve efficiency and reduce system cost. However, it was difficult to operate large scale fuel cell without humidifying, especially higher than $50{\sim}60^{\circ}C$. In case of small flux such as 0.78 L/min, temperature difference between inlet and outlet was occurred larger than other cases resulting performance decrease. Non-humidifying performance experiments were done at various cell temperature. When both of anode and cathode humidification were removed, cell performance was strongly depended on cell operating temperature.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.38 no.1
• /
• pp.30-38
• /
• 2018

This study was conducted to explore the effects of seeding rate of a seed mixture on grassland productivity and botanical composition. Seeding rates were composed of four different treatments varying by the amount of seed: T1, 50% decrease in seeding rate from standard; T2, standard seeding rate; T3, 50% increase in seeding rate from standard; and T4, 100% increase in seeding rate from standard. In 2016, seasonal changes in grass botanical composition revealed T2, T3, and T4 in portion of grass ratio were the highest with a range of 87-100%, whereas T1 was the lowest of all treatments. In 2017, the botanical composition in T1 showed that the grass ratio in of the first cutting was 91%, but in the fourth cutting its ratio decreased by 75%. The results from both years were combined for each treatment, T4 ($11,435kg\;ha^{-1}$) and T3 ($11,162kg\;ha^{-1}$) demonstrated the highest dry matter yield of the treatments (T1: $8,196kg\;ha^{-1}$; T2: $9,521kg\;ha^{-1}$) (p<0.05). As a result, a 50-100% increase in the seeding rate from the standard demonstrated the best grassland yield and botanical composition.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.5
• /
• pp.628-636
• /
• 2018

Because large buoys are mainly made of steel, they are heavy and vulnerable to corrosion by sea water. This makes buoy installation and maintenance difficult. Moreover, vessel collision accidents with buoys and damage to vessels due to the material of buoys (e.g., steel) are reported every year. Recently, light buoys adopting eco-friendly and lightweight materials have come into the spotlight in order to solve the previously-mentioned problems. In Korea, a new lightweight buoy with a 7-Nautical Mile lantern adopting expanded polypropylene (EPP) and aluminum to create a buoyant body and tower structure, respectively, was developed in 2017. When these light buoys are operated in the ocean, the visibility and angle of light from the lantern installed on the light buoys changes, which may cause them to function improperly. Therefore, research on the performance of light buoys is needed since the weight distribution and motion characteristics of these new buoys differ from conventional models. In this study, stability estimation and motion analyses for newly-developed buoys under various environmental conditions considering a mooring line were carried out using ANSYS AQWA. Numerical simulations for the estimation of wind and current loads were performed using commercial CFD software, Siemens STAR-CCM+, to increase the accuracy of motion analysis. By comparing the estimated maximum significant motions of the light buoys, it was found that waves and currents were more influential in the motion of the buoys. And, the estimated motions of the buoys became larger as the sea state became worser, which might be the reason that the peak frequencies of the wave spectra got closer to those of the buoys.

• Journal of the Korean Dietetic Association
• /
• v.8 no.3
• /
• pp.280-288
• /
• 2002

The purpose of this study was to investigate the operational characteristics of the contract-managed highschool foodservice and to analyze the factors to effect the menu price. The data was collected from 249 highschools in Seoul. The results are as follows; Those surveyed highschools were established as 1 national, 74 public, and 174 private institution. Highschools were classified as 176 academic, 66 vocational, and 7 specific purposed institution. Students were organized as 70 boys', 23 girls', and 41 coeducational highschools. Most highschool started contract-managed highschool foodservice from 1999 and the period of foodservice contract was most 3 years and the operation styles in food distribution were 96 classrooms, 105 dining halls and 17 classrooms combined dining halls. The scale of contract foodservice management companies was 63.1% small and medium and 36.9% large enterprises. The surveyed highschools had the average meal price 2,141 won per meal and they had 1,518 pupils on the register. The participating rate to the foodservice was 68.5%. The facilities investment cost of the contract foodservice management company was 179,204,230 won for private institutions and was 138,119,010 won for national&public institutions. The period of the contract was 3.22 years in private institutions, which was significantly higher than national&public institutions which showed 2.85 years. The commissary foodservice schools had higher facilities investment cost than conventional foodservice schools. Classrooms foodservice had higher participating foodservice rate than Dining halls. The investment cost for facilities showed high in order of girls', boys', and coeducational high schools, and the number on the register and the number participating in the foodservice showed high in order of boys', girls', and coeducational high schools. The number on the register showed the highest in academic and vocational schools, specific purposed institutions in sequence, and the number participating in the foodservice showed high in order of academic schools, specific purposed institutions and vocational. However, the participating foodservice rate showed high in specific purposed institution, academic and vocational schools in order, and the meal price, the investment cost for facilities showed high in specific purposed institution, academic and vocational schools in sequence. Regionally, the district south of Han river had the average meal price 2,266.13 won, which showed higher in the eastern part which had 2,033.33 won. The western part had the average investment cost for facilities of 233,331,060 won, and the central district 126,137,140 won. The number on the register showed 1845.68 in the eastern part and 1308.00 in Dong-Jak area, that had clear differences among areas. When the period of the contract went longer, the investment cost for facilities had a tendency to increase. The significant differences were existed among meal price, the investment cost for facilities, the number on the register, the number participating in the foodservice, and the participating foodservice rate. The investment cost for facilities had increased according to the number participating in the foodservice and the participating foodservice rate. And the large enterprises showed higher participating foodservice rate than the small and medium enterprises.

• Journal of Chest Surgery
• /
• v.36 no.11
• /
• pp.846-851
• /
• 2003

Background: To clarify the clinical significance of the aortic nodes in resected non-small cell lung cancer of the left upper lobe. Material and Method: One hundred fifty six patients with resected non-small cell lung cancer of the left upper lobe were studied. Patients who received preoperative induction therapy, non-curative operation or defined as operative mortality were excluded from this study. Result: In N2 left upper lobe tumors, aortic nodes comprised 52.7% of the metastatic mediastinal lymph nodes. In single station N2 disease, a frequently metastasized station was aortic node (64.3%). 5-year actuarial survival according to the N status was 65.0% in N0, 30.4% in N1, and 17.9% in N2. There was no statistically significant difference in survival between N1 and N2 diseases (p=0.06). The patients with metastasis to aortic node alone had a comparatively good prognosis (5-year survival: 35.6%) than other N2 diseases (5-year survival: 4.6%) (p=0.01) and had a similar survival outcome as N1 diseases (p=0.97). Considering the aortic node as N1 node, 5-year survival according to the N status was 65.0% in N0, 31.2% in N1, 4.6% in N2 and significant survival difference was observed between N1 and N2 disease (p=0.00). In multivariate analysis, the male sex (hazard ratio 6.892, p=0.011) and the involvement to the aortic node alone (hazards ratio 2.799, p=0.009) were the significant factors affecting postoperative survival. Conclusion: According to the our data, involvement to the aortic node alone in left upper lobe tumors should be grouped with N1 disease because this combined category reflects the surgical outcome more accurately.

• Journal of Chest Surgery
• /
• v.32 no.1
• /
• pp.1-4
• /
• 1999

Background: The transplantation of organs between phylogenetically disparate or harmonious species has invariably failed due to the occurrence of hyperacute rejection or accerelated acute rejection. But, concordant cardiac xenograft offer us an opportunity to study xenotransplantation in the absence of hyperacute rejection. Current therapeutics for the prolongation of survival of rodent concordant xenotransplantation are not ideal with many regimens having a high mortality rate. Cyclosporine A & Mycophenolate Mofetil are new immunosuppresive agent which has been shown to be effective at prolonging survival of allograft, as purine synthesis inhibitor. Material and Method: We used white mongrel rats as recipient and mice as donor, divided 4 groups(n=6), control group(Group 1) has no medication or pretreatment, Group 2 has splenectomy as pretreatment 7∼10 days before transplantation, Group 3 has Cyclosporine A treatment group, Group 4 has combined treatment of Cyclosporine A & Mycophenolate Mofetil(RS 61443). We compared survival time. Reuslt: We can't find significant difference of survival time between each groups. Conclusion: We concluded that rejection of cardiac xenograft was different from rejection of allograft, and new immunossuppresive Agent(Mycophenolate Mofetil, Cyclosporine A) was not effective for prolongation of survival time after cardiac xenograft.

• Korea journal of population studies
• /
• v.26 no.2
• /
• pp.1-32
• /
• 2003

An analysis on cause-specific mortality at the provincial level provides essential information for policy formulation and makes it possible to draw hypotheses regarding various diseases and causes of death. Although the mortality level and causes of death at the provincial level are determined by the multiple effects of socioeconomic, cultural, medical and ecological factors, this study primarily intends to examine similarities and differences of cause-specific mortality at the provincial level. Utilizing the registered death and the registered population as of 1998, the delayed death registration and unreported infant deaths were supplemented at the provincial level and age-standardized death rates and life tables were calculated. Regarding the mortality level due to all causes, major findings were as follow: (1) For both sexes as a whole, Seoul showed the lowest mortality level, and Jeonnam showed the highest mortality level; and (2) The differences of the mortality level among provinces were greater for males than females and for those less than 65 years than those 65 years and over. Regarding the cause-specific mortality level revealed in all indicators (cause-specific age-standardized mortality rates and the probability of dying at birth due to a specific cause for males, females, and both sexes combined respectively), the major findings were as follow: (1) The mortality level due to heart diseases was the highest in Busan and the lowest in Gangweon; (2) The mortality level due to liver diseases was the highest in Chonnam; and (3) The mortality level due to traffic accidents was the highest in Chungnam and the lowest in Inchon. As the mortality differentials at the provincial level are related to various factors, exploratory statistical analysis is attempted for the 25 explanatory variables including socioeconomic variables and 90 mortality variables. Mortality due to all causes are related to socioeconomic variables. Among cause-specific mortality, mortality due to liver diseases and traffic accidents is related to socioeconomic variables. Finally, the need to improve the quality of death certificate is discussed.