• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1993년도 제2회 신약개발 연구발표회 초록집
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• pp.46-46
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• 1993

The neuroprotective effect of betaine, one of the , components of Lycii Fructus, on glutamate-induced neurotoxicity in primary cultured chicken brain cells were examined. Betaine was found to attenuate glutamate-induced neurotoxicity at the concentration of 5-10 mM in both morphological and chemical aspects. The pretreament of chicken brain cells with 5-10 mM betaine for 2 hr at the 12th day of culture before the 40 min-exposure to 500${\mu}$M glutamate significantly increased the survival rate of nerve cells in chicken brain. Betaine could also raise the decreased LDH-level due to the neurotoxicity induced with 100${\mu}$M glutamate in chicken braill cells. LDH value was decreased to 63％ of control level in chicken brain cells at the time of 48 hr after the exposure to glutamate. However, the pretreament of chicken brain cells with 5 mM betaine for 2 hr before the exposure to glutamate could prevent the decrease of LDH-level in brain cells showing 90％ of control level. Nevertheless, tile remarkable neuroprotective effect of betaine on the glutamate-inducer in neurotoxicity in cultured chicken brain cells could not be observe when betaine was simultaneously administered with glutamate.

• 한국산업보건학회지
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• 제1권2호
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• pp.192-199
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• 1991

Biological exposure indices (BEI) of toluene, perchloroethylene (PCE) and methyl ethyl ketone (MEK) for Korean workers were studied respectively. Environmental exposures in workplace to organic solvent were measured by personal sampling. Blood toluene, blood perchloroethylene, urinary trichloroacetic acid and urinary MEK were determined by headspace gas chromatography. Urinary hippuric acid were determined by HPLC and corrected by creatinine. BEIs for Korean workers were calculated as the levels of determinants which are correspond to permissible exposure limits in Korea. Blood toluene level of 2.2mg/l and urinary hippuric acid level of 1.7g/g creatinine are correspond to an exposure of 100 ppm toluene. Blood PCE concentration of 1.6mg/l and urinary trichloroacetic acid concentration of 2.9mg/l are correspond to an exposure of 50ppm PCE. Urinary MEK concentration of 1.0mg/l is correspond to an exposure of 200ppm of MEK. BEIs for Korean workers determined in this study are very different to ACGIH's BEI as urinary determinants are much lower and blood determinants are much higher than ACGIH's BEI.

• 한국환경보건학회지
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• 제26권4호
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• pp.58-64
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• 2000

Indoor air quality tends to be the dominant contributor to personal exposure, because most people spend over 80% of their time indoors. In this study, indoor and outdoor NO$_2$ concentrations were measured and compared with simultaneously personal exposures of 21 university students in weekday and weekend. House characteristics and activity pattern were used to determine the impacts of these factors on personal exposure. Since university students spent most of their times in indoor, their NO$_2$ exposure was associated with indoor NO$_2$ level rather than outdoor NO$_2$ level both weekday and weekend in spite of different time activity. Using time-weighted average model, NO$_2$ exposures of university students were estimated by NO$_2$ measurements in indoor home, indoor school, and outdoor home levels. Estimated NO$_2$ personal exposures were significantly correlated with measured NO$_2$ personal exposures($r^2$=0.87). However, estimated personal NO$_2$ exposures by time-weighted average model were underestimated, comparing with the measured personal NO$_2$ exposure. Using multiple regression analysis, effect of personal NO$_2$ exposure for transportation was confirmed.

• 한국산업보건학회지
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• 제23권2호
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• pp.41-49
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• 2013

Objectives: The purpose of this study was to clarify the association between serum carcinoembryonic antigen (CEA) and type of work in the shipbuilding industry. Methods: 1,072 final study subjects were admitted to a general hospital from April through July 2010 for the purpose of medical examination. Data on general characteristics such as age, smoking history, alcohol history and exercise habits was gathered through structured self-administered questionnaires. Information on job factors was collected from a medical examination, by interview and through company personnel data. Serum CEA levels were measured after eight hours' fasting and were analyzed by a radioimmunoassay. Results: On univariate analysis, the mean serum CEA level was significantly higher among married (p=0.02), older age (p<0.01), longer work time (p<0.01), smokers (p<0.01), lower education (p<0.01), and indirect and direct exposure groups (p<0.01). On multiple regression analysis, serum CEA level was influenced by smoking (p=0.001), duration of work (p=0.019), and direct exposure group (p<0.001). However, among the direct exposure group, serum CEA level was not significantly different between welding, mounting, electro-device constructive work, grinding and cleaning, and painting. Conclusions: The goal of this research was to determine if there were differences between serum CEA levels according to occupational role among shipyard workers. The direct exposure group of shipyard workers had a relatively higher level of serum CEA than did the indirect exposure group and office workers, most likely due to occupational exposure.

• 한국환경보건학회지
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• 제33권5호
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• pp.386-391
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• 2007

Mercury contamination and its health effects have become major concern of environmental health study in Korea. Mercury exposure of some group were investigated to get the accurate data for policy making and study. About 2,000 children at 26 elementary schools participated in this survey to evaluate the exposure levels and to investigate main exposure source of mercury. Analysis of mercury levels in the whole blood and urine samples were conducted and questionnaire survey was done about the factors influencing exposures simultaneously. Mercury exposure levels of domestic children were N.D. to 17.26 ppb in blood, 0.17 to $21.67{\mu}g/g$-creatinine in urine. The mean(arithmetic) levels are 2.42 ppb in blood and $2.53{\mu}g/g$-creatinine in urine. Both of them were below the recommendation levels of US EPA and German CHBM I $5.8{\mu}g/l$ and $5{\mu}g/l$ in blood, $5{\mu}g/g$-creatinine of German CHBM I in urine. But 1%, 0.51% of levels in blood exceed the level of CHBM I and US EPA, 8%, 0.85% of children were over the level of CHBM I and CHBM II in urine. Multi-valuable regression analysis showed that the existence of road near the residence in addition to the preference for fish have significance with blood mercury exposure level of domestic children. The existence of factory near the house and the experience of dental amalgam treatment had statistical relations with urine mercury level.

• 한국산업보건학회지
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• 제28권2호
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• pp.144-150
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• 2018

Objectives: The purpose of this study is to analyze the trend for exceedance of the domestic permissible exposure limit of benzene based on a review of the previous literature. Materials and methods: From among 13 chemical substances regulated through a PEL (Permissible Exposure Limit) in the Occupational Safety and Health Act, the research object of this study is benzene. The information utilized is work environment measurement data from 2004 to 2013. The highest level among the concentration data measured at various workplaces was selected as a representative value through the data process. N.D. (Not Detected) data was considered as 1/2 of the LOD (limit of detection). Results: Among the work environment measurement data between 2004 and 2013, the highest number of exceeding workplaces and the excess rate (12 sites and 5.4%) was observed in the 2006 data when applying the current PEL for benzene. When compared with the action level, which means a level one-half of the PEL, 2005's data showed the highest number of exceeding workplaces and greatest excess rate (89 sites & 13.3%). The number of exceeding workplaces and excess rate relative to the PEL for benzene showed an increasing trend in 2004, but tended to decrease after 2007. Conclusions: Based on the results obtained from this study, the exposure level for benzene among domestic workers is not considered to be in a safe phase regardless of the year of work environment measurement. Thus, strict preventive management in workplaces should be provided for reducing exposure to benzene.

• Safety and Health at Work
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• 제11권2호
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• pp.199-206
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• 2020

Background: In a wide range of industries, noise-induced hearing loss remains one of the most prevalent occupational problems. This study aimed to assess the noise exposure level and associated factors of hearing loss among textile workers in Yangon Region, Myanmar. Methods: A cross-sectional study was conducted at a Textile mill (Thamine), Yangon Region, from April to December 2018. In total, 226 workers who were randomly selected from 3 weaving sections participated in face-to-face interviews using a structured questionnaire. A digital sound level meter and pure-tone audiometer were used for the assessment of noise exposure level and hearing loss, respectively. Logistic regression analysis was performed to assess the associated factors of hearing loss. Results: In total workers, 66.4% were exposed to ≥85 dB(A) of noise exposure, and the prevalence of hearing loss was 25.7%. Age ≥35 years, below high school education, hearing difficulty, tinnitus, hypertension, > 9 years of service duration in a textile mill were positively associated with hearing loss. After adjusting confounding factors, age ≥35 years (adjusted odds ratio = 6.90, 95% confidence interval = 3.45-13.82) and tinnitus (adjusted odds ratio = 2.88, 95% confidence interval = 1.13-7.37) were persistently associated with hearing loss. Conclusion: Providing occupational hazard education and enforcement of occupational safety regulations should be taken to decrease the noise exposure level. The regular audiometry test should be conducted for assessment of hearing threshold shift. The employer needs to implement a hearing conservation program in workplace when noise exposure reaches or exceeds 85 dB(A) for 8 hours.

• 한국대기환경학회지
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• 제11권4호
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• pp.323-329
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• 1995

The number of motor vehicles in Korea has increased to about 4 million, and the exhaust gases of these vehicles have become a more threatening factor to public health. Traffic policemen are one of the highest health risk groups since they work on roadsides where they are exposed to high levels of air pollutants. The health effects on them due to air pollution were determined by measuring personal carbon monoxide(CO) exposure and carboxyhemoglobin(COHb) level in blood. Thirty-one traffic policemen in Seoul volunteered to be subjects of the study. In October 1992, personal CO exposure was measured by a CO passive sampler. The subjects wore the CO passive sampler for 8 hours while on duty. The exposed samples were analyzed by gas chromatography. Blood samples from each subject were collected just after the exposure sampling, and were analyzed within 3 hours of blood collection by a CO-oximeter. The activities of the subjects were recorded by the subject in 30 minute intervals using an activity log sheet containing location and time spent. Personal CO exposure were ranged between 0.1 and 14.5ppm, eith an average of 5.9ppm. Carboxyhemoglobin levels ranged from 1.1% to 6.9%, with an average of 3.6%. policemen on duty outdoors had significantly higher CO exposures and COHb levels than policemen on duty indoors(p<0.01). Personal CO exposure and COHb were positively correlated, although the coefficient was not significant. The relationship between CO level and COHb level was confounded by smoking status. Among smokers, COHb level was significantly higher as CO exposure and hours worked outdoors increased.

• 한국산업보건학회지
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• 제23권3호
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• pp.261-265
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• 2013

The purpose of this study was to evaluate noise level exposures at different locations such as the left and right ears of the shooter, control room, waiting soldier location and drill ground. For this study, we visited two military rifle ranges and took measurements with a sound level meter (3M Quest SoundPro TM) at five different locations with values of Peak (dB(A)) and Max (dB(A)). The highest peak value of impulse noise level averaged 150.4 dB(A), ranging from 149.6 to 150.5 dB(A) at both the left and right ear sides. This result was significantly different between both left and right ear side locations and at other locations such as the control room, waiting soldier location, and drill ground (P < 0.001). Frequency of impulse noise exposure level showed that the left ear of shooter had the highest frequency (20 times) at over 150 dB(A). This study confirmed that there is a need for proper controls to reduce the amount of impulse noise exposure at military rifle ranges.

• 한국소음진동공학회논문집
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• 제21권5호
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• pp.400-407
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• 2011

The suggested method of previous Son's study dichotomized subjective response data to modeling noise exposure-response. The method used maximum liklihood estimation instead of least square estimation and the noise exposure-response curve of the study was logistic regression analysis result. The method was originated to modeling community response rate such as %HA or %A. It can be useful when the subjective response was investigated based on predicted noise level. It is difficult to measure the single source emitting noise such as railway because various traffic noise sources combined in our life. The suggested method was adopted to model in this study and railway noise-exposure response curves were modeled because the noise level of this area was predicted data. The data of this study was used by previous Ko's paper but he dealt the area as combined noise area and divided the data by dominant noise source. But this study used all data of this area because the annoyance response to railway noise was higher than other noise according to the result of correlation analysis. The trend of the %HA and %A prediction model to train noise of this study is almost same as the model based on measured noise of previous Lim's study although the investigated areas and methods were different.