Mechanism Underlying NaF-Induced Apoptosis in Human Oral Squamous Cell Carcinoma

Few studies have evaluated the apoptosis-inducing efficacy of NaF on cancer cells in vitro but there has been no previous investigation of the apoptotic effects of NaF on human oral squamous cell carcinoma cells. In this study, we have investigated the mechanisms underlying the apoptotic response to NaF treatment in the YD9 human squamous cell carcinoma cell line. The viability of YD9 cells and their growth inhibition were assessed by MTT and clonogenic assays, respectively. Hoechst staining, DNA electrophoresis and TUNEL staining were conducted to detect apoptosis. YD9 cells were treated with NaF, and western blotting, immunocytochemistry, confocal microscopy, FACScan flow cytometry, and MMP and proteasome activity assays were performed sequentially. The NaF treatment resulted in a time- and dose-dependent decrease in YD9 cell viability, a dose-dependent inhibition of cell growth, and the induction of apoptotic cell death. The apoptotic response of these cells was manifested by nuclear condensation, DNA fragmentation, the reduction of MMP and proteasome activity, a decreased DNA content, the release of cytochrome c into the cytosol, the translocation of AIF and DFF40 (CAD) into the nucleus, a significant shift of the Bax/Bcl-2 ratio, and the activation of caspase-9, caspase-3, PARP, Lamin A/C and DFF45 (ICAD). Furthermore, NaF treatment resulted in the downregulation of G1 cell cyclerelated proteins, and upregulation of p53 and the Cdk inhibitor p27KIP1. Taken collectively, our present findings demonstrate that NaF strongly inhibits YD9 cell proliferation by modulating the expression of G1 cell cycle-related proteins and inducing apoptosis via mitochondrial and caspase pathways.

Mechanism Underlying NaF-Induced Apoptosis in Human Oral Squamous Cell Carcinoma

Few studies have evaluated the apoptosis-inducing efficacy of NaF on cancer cells in vitro but there has been no previous investigation of the apoptotic effects of NaF on human oral squamous cell carcinoma cells. In this study, we have investigated the mechanisms underlying the apoptotic response to NaF treatment in the YD9 human squamous cell carcinoma cell line. The viability of YD9 cells and their growth inhibition were assessed by MTT and clonogenic assays, respectively. Hoechst staining, DNA electrophoresis and TUNEL staining were conducted to detect apoptosis. YD9 cells were treated with NaF, and western blotting, immunocytochemistry, confocal microscopy, FACScan flow cytometry, and MMP and proteasome activity assays were performed sequentially. The NaF treatment resulted in a time- and dose-dependent decrease in YD9 cell viability, a dose-dependent inhibition of cell growth, and the induction of apoptotic cell death. The apoptotic response of these cells was manifested by nuclear condensation, DNA fragmentation, the reduction of MMP and proteasome activity, a decreased DNA content, the release of cytochrome c into the cytosol, the translocation of AIF and DFF40 (CAD) into the nucleus, a significant shift of the Bax/Bcl-2 ratio, and the activation of caspase-9, caspase-3, PARP, Lamin A/C and DFF45 (ICAD). Furthermore, NaF treatment resulted in the downregulation of G1 cell cyclerelated proteins, and upregulation of p53 and the Cdk inhibitor p27KIP1. Taken collectively, our present findings demonstrate that NaF strongly inhibits YD9 cell proliferation by modulating the expression of G1 cell cycle-related proteins and inducing apoptosis via mitochondrial and caspase pathways.

Apoptotic Effect of Co-treatment with Chios Gum Mastic and HS-1200 on G361 Human Melanoma Cell Line / 대한해부학회지

Chios gum mastic (CGM) is a resinous exudate obtained from the stem and the main leaves of Pistacia lenticulus tree native to Mediterranean areas. Recently it reported that CGM induce apoptosis in a few cancer cells in vitro. Bile acids and their synthetic derivatives induced apoptosis in various kinds of cancer cells and anticancer effects. It has been reported that the synthetic chenodeoxycholic acid (CDCA) derivatives showed apoptosis-inducing activity on various cancer cells in vitro. This study was undertaken to investigate the synergistic apoptotic effect of cotreatment with a natural product, CGM and a CDCA derivative, HS-1200 on G361 human melanoma cells. To investigate whether the co-treatment of CGM and HS-1200 compared with each single treatment efficiently reduced the viability of G361 cells, MTT assay was conducted. To investigate augmentation of apoptosis in G631 cells co-treated with CGM and HS-1200, DNA electrophoresis, Hoechst staining, proteasome activity assay, flow cytometry, Westen blot analyses, immunofluorescent staining and confocal microscopy were performed. In this study, G361 cells co-treated with CGM and HS-1200 showed several lines of apoptotic manifestation such as nuclear condensations, DNA fragmentation, the reduction of MMP and proteasome activity, the decrease of DNA content, the release of cytochrome c into cytosol, the translocation of AIF and DFF40 (CAD) onto nuclei, activation of caspase-9, caspase-3, PARP and DFF45 (ICAD), and up-regulation of Bax whereas each single treated G361 cells did not. Although the single treatment of 40 micro/mL CGM or 25 micro HS-1200 for 24 hrs did not induce apoptosis, the co-treatment of them induced prominently apoptosis. Therefore, combination therapy of CGM and HS-1200 could be considered, in the future, as an alternative therapeutic strategy for human melanoma.

An outbreak of inapparent non-O157 enterohemorrhagic escherichia coli infection / 대한내과학회지

BACKGROUND: No outbreak of Enterohemorrhagic Escherichia coli (EHEC) infection has occurred as a group in Korea. On July 2004, an outbreak of EHEC infection occurred in an elementary school in Gwangju metropolitan city. Epidemic investigation was undertaken to track the source of infection and the mode of transmission of EHEC. METHODS: All students and staffs of the elementary school were interviewed and completed questionnaires. We surveyed their clinical symptoms and the foods that they ate. Microbiologic examinations were also carried out on the above school-related persons and many environmental specimens. We also investigated the facilities of the school, some suppliers of food materials, and other associated institutions. All the EHEC-positive persons were isolated in 5 hospitals and tested everyday for verotoxin until they turned out to be negative twice in succession, and their family were also interviewed and tested for EHEC. Pulsed-field gel electrophoresis (PFGE) was performed to find out the genetic relationship between isolates. RESULTS: Of the 1,643 school-related persons, 77 persons (4.7%) were positive for EHEC. Most of them were asymptomatic. All the isolated strains were non-O157 EHEC. Serotype O91 was the most frequent serotype (68 isolates), and the isolates revealing O91 serotypes showed identical PFGE patterns. The school meal was significantly associated with this outbreak (relative risk=13.29, p=0.00). CONCLUSIONS: This is the first EHEC outbreak occurred as a group in Korea, All the isolated strains were non-O157 serotypes and the mode of transmission was most likely by school meal.

Evaluation of the Completeness of Case Reporting during the 1998 Cheju-do Mumps Epidemic, Using Capture-recapture Methods / 예방의학회지

OBJECTIVES: To estimate mumps incidence during the study period and to evaluate the completeness of case reporting. METHODS: Capture-recapture methods, originally developed for counting wildlife animals, were used. The data sources were 1) the National Notifiable Communicable Disease Reporting System (NNCDRS; 848 cases), 2) the School Health Reporting System, temporarily administered by the Division of Education (SHRS; 1,026 cases), and 3) a survey of students (785 cases). We estimated the number of unobserved mumps cases by matching the three data sources and fitting loglinear models to the data. We then determined the estimated total number of mumps cases by adding this to the number of observed cases. Completeness was defined as the proportion of observed cases from each source to the total of estimated cases. RESULTS: The total number of observed cases was 1,844 and the total number of estimated cases was 1,935 (95% CI: 1,878-2,070). The overall completeness was 43.8% of the NNCDRS, 53.0% of the SHRS, and 40.6% of the survey. However, completeness varied by area and age. CONCLUSION: Although the completeness of NNCDRS data appeared higher than in the past, it is difficult to generalize this result. In Korea, it is possible to estimate the size of health hazards relatively cheaply and quickly, by applying capture-recapture methods to various data using a multiple data collection system.

An Epidemiologic Investigation of Shigella Sonnei Outbreak at a Primary School in Taegu city / 한국역학회지

PURPOSES: This study was conducted to determine the source of infection and mode of transmission of the shigellosis outbreak on March 27, 1998 at a primary school in Taegu city. METHODS: On-site interview using a standard questionnaire and rectal swab were conducted to 1,629 peoples who ate lunch on March 26 and 1,389 peoples who contacted with suspected cases. And bacteriological examination for 91 environmental materials and 25 food items were performed. RESULTS: Of the 1,629 persons who ate lunch on March 26, seventy three had culture-confirmed S. sonnei infection(first attack rate: 4.5%). And additional fifty four had shigellosis among those 1,389 persons who might be exposed to the suspected cases(second attack rate: 3.9%). A total of 730 persons who complained one of four typical symptoms or more were treated as suspected cases(first attack rate of suspected cases: 44.8%). S. sonnei was never isolated from water, foods, and other environmental materials. The median incubation period was estimated about two days. The common symptom reported were diarrhea(88.7%), fever(73.4%), abdominal pain(54.7%), and vomiting episode(38.4%) in order. The shorter duration of the outbreak and the large proportion of cases involving students who ate lunch on March 26 are consistent with fecal-oral transmission, although the limited epidemiologic data obtainable do not clearly define the route of transmission. CONCLUSIONS: Thus the outbreak reported here appear to be related to the unsanitary conditions of food facility in this school.

A path analysis on prisoners' health behavior and medical utilization

In this thesis, Korean prisoners' health behavior and the characteristics of their medical utilization were surveyed and analysed. Because prisoners are inclined to be mediators of communicable diseases or unhealthy behaviors between prison institution and the outside world, health care for prisoners is directly related to the national population. Data were collected through a self-administered survey of 5 Korean prisons out of a total of 38 correctional facilities and analysed in accordance with a causal model based on a path frame, by serial multiple regressions on health behavior, health status, and medical utilization, etc. According to the survey analysis, while prisoners were generally concerned with their health much more than they were before imprisonment, they perceived that their health status had deteriorated after imprisonment, and that their need for health services was increasing gradually during their time in prison. In the path analysis on the causal relations among variables related to the prisoners' health status and medical utilization, the prisoners' characteristics affected their health concern and health behavior, and subsequently affected their health status and medical utilization, respectively. To sum up these exploratory studies on prisoners' health behavior and health service utilization, some efforts to organize a health care system embracing the correctional institution and health care administration should be made on the level of establishing a health care delivery system for special social groups like prisoners.