• Journal of Life Science
• /
• v.19 no.7
• /
• pp.871-877
• /
• 2009

We investigated the effects of sodium butyrate, a histone deacetylase inhibitor, on the cell cycle progression in human monocytic leukemia U937 cells. Exposure of U937 cells to sodium butyrate resulted in growth inhibition, G1 arrest of the cell cycle and induction of apoptosis in a dose-dependent manner as measured by MTT assay and flow cytometry analysis. The increase in G1 arrest was associated with the down-regulation in cyclin D1, E, A, cyclin-dependent kinase (Cdk) 4 and 6 expression, and up-regulation of Cdk inhibitors such as p21 and p27. Sodium butyrate treatment also inhibited the phosphorylation of retinoblastoma protein (pRB) and p130, however, the levels of transcription factors E2F-1 and E2F-4 were not markedly modulated. Furthermore, the down-regulation of phosphorylation of pRB and p130 by this compound was associated with enhanced binding of pRB and E2F-1, as well as p130 and E2F-4, respectively. Overall, the present results demonstrate a combined mechanism involving the inhibition of pRBjp130 phosphorylation and induction of Cdk inhibitors as targets for sodium butyrate that may explain some of its anti-cancer effects in U937 cells.

• Microbiology and Biotechnology Letters
• /
• v.38 no.2
• /
• pp.198-206
• /
• 2010

The aim of this work was to investigate the synergically bactericidal effects and cellular responses of tea polyphenols (TPP) and imipenem on imipenem-resistant Pseudomonas aeruginosa. Imipenem-resistant Ps. aeruginosa was isolated from patient in hospital. The bactericidal effects of TPP and imipenem were evaluated on the basis of its minimum inhibitory concentrations (MIC). The combined use of TPP and imipenem resulted in 16-fold and 8-fold reductions in the MICs of imipenem for the imipenem-susceptible and imipenem-resistant Ps. aeruginosa, respectively. The bactericidal effects of the imipenem and TPP against the Ps. aeruginosa was evaluated using the time-kill assay. The synergetic effects of the combinations of TPP and imipenem against Ps. aeruginosa were confirmed. Western blot using anti-DnaK and anti-GroEL monoclonal antibodies was performed to investigate the expression of stress shock proteins (SSPs) in imipenem-susceptible and imipenem-resistant strains exposed to TPP. The amount of SSPs were induced as the exposure time increased and decreased. The molecular weights of DnaK and GroEL were 70 kDa and 60 kDa, respectively. SDS-PAGE with silver staining revealed that the amount of lipopolysaccharides (LPS) increased or decreased in the strain treated to different concentrations and exposing periods of TPP. Scanning electron microscopic analysis demonstrated the presence of umblicated and wrinkled surfaces for cells treated with TPP or imipenem.

• Journal of health informatics and statistics
• /
• v.42 no.4
• /
• pp.309-316
• /
• 2017

Objectives: Radon and its progeny pose environmental risks as a carcinogen, especially to the lungs. Investigating factors affecting indoor radon concentrations and models thereof are needed to prevent exposure to radon and to reduce indoor radon concentrations. The purpose of this study was to identify factors affecting indoor radon concentration and to construct a comprehensive model thereof. Methods: Questionnaires were administered to obtain data on residential environments, including building materials and life style. Decision tree and structural equation modeling were applied to predict residences at risk for higher radon concentrations and to develop the comprehensive model. Results: Greenery ratio, impermeable layer ratio, residence at ground level, daily ventilation, long-term heating, crack around the measuring device, and bedroom were significantly shown to be predictive factors of higher indoor radon concentrations. Daily ventilation reduced the probability of homes having indoor radon concentrations ${\geq}200Bq/m^3$ by 11.6%. Meanwhile, a greenery ratio ${\geq}65%$ without daily ventilation increased this probability by 15.3% compared to daily ventilation. The constructed model indicated greenery ratio and ventilation rate directly affecting indoor radon concentrations. Conclusions: Our model highlights the combined influences of geographical properties, groundwater, and lifestyle factors of an individual resident on indoor radon concentrations in Korea.

• Restorative Dentistry and Endodontics
• /
• v.48 no.4
• /
• pp.39.1-39.23
• /
• 2023

Objectives: This study aimed to investigate the effectiveness of different topical/systemic agents in reducing the damage caused by bleaching gel to pulp tissue or cells. Materials and Methods: Electronic searches were performed in July 2023. In vivo and in vitro studies evaluating the effects of different topical or systemic agents on pulp inflammation or cytotoxicity after exposure to bleaching agents were included. The risk of bias was assessed. Results: Out of 1,112 articles, 27 were included. Nine animal studies evaluated remineralizing/anti-inflammatories agents in rat molars subjected to bleaching with 35%-38% hydrogen peroxide (HP). Five of these studies demonstrated a significant reduction in inflammation caused by HP when combined with bioglass or MI Paste Plus (GC America), or following KF-desensitizing or Otosporin treatment (n = 3). However, orally administered drugs did not reduce pulp inflammation (n = 4). Cytotoxicity (n = 17) was primarily assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on human dental pulp cells and mouse dental papilla Cell-23 cells. Certain substances, including sodium ascorbate, butein, manganese chloride, and peroxidase, were found to reduce cytotoxicity, particularly when applied prior to bleaching. The risk of bias was high in animal studies and low in laboratory studies. Conclusions: Few in vivo studies have evaluated agents to reduce the damage caused by bleaching gel to pulp tissue. Within the limitations of these studies, it was found that topical agents were effective in reducing pulp inflammation in animals and cytotoxicity. Further analyses with human pulp are required to substantiate these findings.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.21 no.2
• /
• pp.117-127
• /
• 2023

Purpose: No consensus currently exists regarding the maximal pressure of hyperbaric oxygen (HBO₂) therapy performed within 24 hours of acute carbon monoxide (CO) poisoning. This study aimed to evaluate the difference in therapeutic effects according to the first HBO₂ pressure (3.0 atmospheres absolute [ATA] vs. 2.8 ATA). Methods: We used prospectively collected registry data on CO poisoning at a tertiary academic hospital in the Republic of Korea. Adult patients with acute CO poisoning treated with HBO₂ within 24 hours after arrival at the emergency department and without the use of additional HBO₂ after 24 hours between January 2007 and February 2022 were included. Data from 595 patients were analyzed using propensity score matching (PSM). Patients with mild (non-intubated) and severe (intubated) poisoning were also compared. Neurocognitive outcomes at 1 month after CO poisoning were evaluated using the Global Deterioration Scale combined with neurological impairment. Results: After PSM, the neurocognitive outcomes at 1-month post-CO exposure were not significantly different between the 2.8 ATA (110 patients) and 3.0 ATA (55 patients) groups (p=1.000). Similarly, there was also no significant difference in outcomes in a subgroup analysis according to poisoning severity in matched patients (165 patients) (mild [non-intubated]: p=0.053; severe [intubated]: p=1.000). Conclusion: Neurocognitive sequelae at 1 month were not significantly different between HBO₂ therapy pressures of 2.8 ATA and 3.0 ATA in patients with acute CO poisoning. In addition, the 1-month neurocognitive sequelae did not differ significantly between intubated and non-intubated patients.

• Journal of Life Science
• /
• v.19 no.9
• /
• pp.1314-1320
• /
• 2009

Histone deacetylase inhibitor (HDACI) is a new promising candidate as an antineoplastic agent for the treatment of solid and hematologic malignancies. In order to evaluate cell death and to elucidate the related mechanism(s) in NSCLC cells after HDACI, sodium butyrate (SB), a representative HDACI, was used to treat H460 cells for 48 hrs. SB exposure resulted in a significant reduction of cell viability at concentrations below 7.5 mM, and about 50% of cell death occurred at 20 mM. The types of cell death induced by SB were both apoptosis and necrosis, evaluated by Annexin-V staining combined with propidium iodide. SB treatment significantly evoked G2/M cell cycle arrest and subsequently induced cell death with caspase-dependent manner. While ERK protein content was not altered after SB, phosphorylated forms of ERK were markedly reduced. Taken together, SB is significantly able to induce cell death in NSCLC cell line H460, and it is suggested that the reduction of ERK phosphorylation might be closely involved in the cancer cell death mechanism initiated by HDACI.

• Journal of Food Hygiene and Safety
• /
• v.33 no.5
• /
• pp.361-368
• /
• 2018

N-nitrosamines are probable or possible human carcinogens, which are produced by the reaction between secondary amines and nitrogen oxide in the acidic environment or by heating. Common risk assessment procedure involves the comparison between exposures expressed in the unit, mg/kg body weight/day and the Health-Based Reference dose expressed in the same unit. This procedure is suitable for the policy decision-making and is considered as inappropriate for the consumers to get information about their dietary decision-making. Therefore, the distributions of NDMA (N-nitrosodimethylamine), NDBA (N-nitrosodibutylamine), the six N-nitrosamines (NDMA, NDBA, NDEA (N-nitrosodiethylamine), NPYR (N-nitrosopyrrolidine), NPIP (N-nitrosopiperidine), and NMOR (N-nitrosomorpholine) in the menus grouped based on the presence of main ingredients and cooking methods were analyzed to generate consumer-friendly information regarding food contaminants. Recipes and intakes were taken from 2014 to 2016 KNHANES (The Korean National Health and Nutrition Examination Survey) and only the data from ages of 7 years or older were used. The contamination data were collected from the 2014~2016 Total Diet Study and all the analysis were performed using R software. Rockfish, eel, anchovy broth and pollock were mainly exposed to N-nitrosamines. In terms of cooking methods, soups and stews appeared to contain the highest amount of N-nitrosamines. Cereals, fruits, and dairy products in the ingredient categories, and rice dishes and rice combined with others in recipe categories had the lowest level exposure to N-nitrosamines. In case of N-nitrosamines, unlike other cooking related food contaminants, boiled dishes such as soups and stews and dishes mainly consisting of fishes and shellfishes had highest level of exposure, showing a large discrepancy with the previous thought of processed meat is the main source of N-nitrosamines.

• Korean Journal of Food Science and Technology
• /
• v.41 no.5
• /
• pp.578-586
• /
• 2009

This study was conducted to determine the effects of alkaline electrolyzed water (AIEW), acidic electrolyzed water (AcEW), 1% citric acid, and 100 ppm sodium hypochlorite, either alone or in combination with citric acid, in reducing the populations of spoilage bacteria and foodborne pathogens (Listeria monocytogenes and Escherichia coli O157:H7) on lettuce at various exposure times (3, 5, and 10 min) with different dipping temperatures (1, 20, 40, and $50^{\circ}C$). In addition, the inhibitory effect of alkaline electrolyzed water combined with citric acid on the browning reaction during storage at $4^{\circ}C$ for 15 days was investigated. Compared to the untreated control, electrolyzed water more effectively reduced the number of total bacteria, mold, and yeast than 100 ppm sodium hypochlorite under the same treatment conditions. All treatments exposed for 5 min significantly reduced the numbers of total bacteria, yeast, and mold on head lettuce. The inactivation effect of each treatment on head lettuce was enhanced as the dipping temperature increased from 1 to $50^{\circ}C$, but there was no significantly difference at temperatures greater than $40^{\circ}C$ (p<0.05). The total counts of yeast and mold in head lettuce were completely eliminated when a combination of 1% citric acid and AlEW treatment was used at temperatures greater than $40^{\circ}C$. However, decreased reduction in L. monocytogenes (2.81 log CFU/g), and E. coli O157:H7 (2.93 log CFU/g) on head lettuce was observed under these treatment conditions. In addition, enhanced anti-browning effect was observed when the samples were subjected to both 1% citric acid and AlEW treatment at temperatures greater than $40^{\circ}C$ compared to when single treatments alone were used. Thus, this combined treatment might be considered a potentially beneficial sanitizing method for improving the quality and safety of head lettuce.

• Korean Journal of Environmental Agriculture
• /
• v.30 no.3
• /
• pp.316-322
• /
• 2011

BACKGROUND: Pesticides concentration was monitored in 50 agricultural lakes, and ecological risk for aquatic organism was assessed using risk quotient (RQ) and probabilistic methods. METHODS AND RESULTS: Pesticides concentrations detected in 50 agricultural lakes during peak season (June and September) were in the range of $0.17{\sim}0.99{\mu}g/L$. The RQ for algae and the other species was estimated to be 0.25 and below 0.01, indicating medium risk and no risk. Oxadiazon predominantly contributed to RQ value of 99% for algae, fishes, and amphibians. In terms of hazardous concentration at 5% of species ($HC_5$), ecological risk quotients (ERQ) for oxadiazon ranged from 0.18~0.33, showing a medium risk level. Overall, the concentrations of pesticides were much lower than $HC_5$), value. Probability of combined ecological risk for pesticides ranged from 1.82% to 2.41%. CONCLUSION(s): Combined ecological risk probability did not exceed the acceptable level of 5%, indicating no ecological risk for selected aquatic species. This study suggests that regular ecological risk assessment (ERA) will be required to protect and manage an agricultural lake. Not only ERA at screening level by comparing exposure with toxic effects for aquatic species also advanced ERA technique considering species in indigenous to Korea, chronic toxicity, pulse dose, fate, and environmental factors should be required.

• Journal of Food Hygiene and Safety
• /
• v.36 no.5
• /
• pp.447-453
• /
• 2021

In this study, the effectiveness of physical control technology, a combined light sterilization (LED, UV) and hot water treatment in reducing Aspergillus ochraceus for food production environment was investigated. In brief, 1 mL aliquot of A. ochraceus spore suspension (10^7-8 spore/mL) was inoculated onto stainless steel chips, which was then dried at 37℃, and each was subjected to different physical treatment. Treatments were performed for 0.5, 1, 2, 5, 8, and 11 hours to reduce the strains using a light-emitting diode, but no significant difference was confirmed among the treatments. However, a significant reduction was observed on the chips treated with UV-C exposure and hot water immersion. After being treated solely with 360 kJ/m² of UV-C on stainless steel chip, the fungi were significantly reduced to 1.27 log CFU/cm². Concerning the hot water treatment, the initial inoculum amount of 6.49 log CFU/cm² was entirely killed by immersion in 83℃ water for 5 minutes. Maintaining a high temperature for 5 minutes at the site is difficult. Thus, considering economic feasibility and usability, we attempted to confirm the appropriate A. ochraceus reduction conditions by combining a relatively low temperature of 60℃ and UV rays. With the combined treatments, even in lukewarm water, A. ochraceus decreased significantly through the increases in the immersion time and the amount of UV-C irradiation, and the yield was below the detection limit. Based on these results, if work tools are immersed in 60℃ lukewarm water for 3 minutes and then placed in a UV sterilization device for more than 10 minutes, the possibility of A. ochraceus cross-contamination during work is expected to be reduced.