도로교통소음에 대한 주민들의 반응

고대하,염정호,권근상,Koh, Dai-Ha,Youm, Jung-Ho,Kwon, Keun-Sang 한국환경보건학회 2004 한국환경보건학회지 Vol.30 No.3

Valid evaluation of community reaction to road-traffic noise exposure is important for the policy making and quality of life. The purpose of this study is to evaluate the relationship between community reaction and nighttime road-traffic noise. The study measured nighttime roadside noise caused by high traffic which is greater than LAeq(22:00-07:00) 65dB(A) and lower than 65dB(A) at Chonju city, from March to April, 2003. Three hundred sixty seven subjects, aged from 20 to 65, were selected from those who are residing close to the major roads. They were asked to answer the questions regarding noise source, stress(PWI-SF), annoyance, disturbance of specific activity, disturbance of sleep, somatic symptom, and four suggested confounding factors. The relationship between annoyance, somatic symptom and noise exposure was not significant. Adjusted odds ratio(95% C.I.) for disturbance of communication and disturbance of attention and rest were 1.59(1.03-2.71), 1.64(1.06-2.81), respectively. On the other hand sleep disturbance was indicated as 1.34(0.77-2.32). The results suggested that federal policy-making about road-traffic noise should consider community reaction evaluated by various perspective including annoyance, disturbance of specific activity, disturbance of sleep, and confounding factors.

Selenium이 mercury, cadmium 및 chromium에 의한 자매염색분체교환(姉妹染色分體交換)의 빈도(頻度)에 미치는 영향(影響)

고대하,기노석,Koh, Dai-Ha,Ki, No-Suk 대한예방의학회 1990 Journal of Preventive Medicine and Public Health Vol.23 No.1

The protective effect of sodium selenite($Na_2SeO_3$) against the cytogenetic toxicity of heavy metals was investigated on human whole-blood cultures in relation to induction of sister chromatid exchange (SCE) in secondary metaphase chromosome. Methylmercury chloride($CH_3HgCl$), cadmium chloride($CdCl_2$), potassium dichromate($K_2Cr_2O_7$), and sodium selenite caused to the typically dose-dependent increase in sister chromatid exchanges (SCEs) by the concentrations ranging from $0.3{\mu}M\;to\;10{mu}M$. However, the inductions of sister chromatid exchanges by methylmercury chloride or cadmium chloride were inhibited by the simultaneous addition of sodium selenite $1.2{mu}M$. The frequencies of SCE were decreased to the level of control in the molar ratios as 2:1, 1:1, 1:2, and 1:4 of selenium selenite vs. methylmercury chloride, and as 1:1 and 1:2 of selenium selenite vs. cadmium chloride, while the frequencies of SCE induced by potassium dichromate were not changed by the addition of sodium selenite in culture condition. Mitotic indices were decreased in the higher concentrations of chemicals and not significantly changed by the simultaneous addition of sodium selenite to the culture condition containing each chemicals. 셀레늄이 수은, 카드뮴 및 크롬의 세포독성에 미치는 영향을 파악하고자 이들 중금속을 $0.3{mu}M$에서 $10{mu}M$까지 6개 농도로 각각 희석하여 $1.2{mu}M$의 셀레늄과 함께 혈액 배양에 첨가하고, 48시간 경과후 fluorescence-plus-Giemsa 염색에 의해 2차분열 중기의 염색체에서 자매염색분체교환(SCE)현상을 관찰하여, 셀레늄을 첨가하지 않았을 때의 결과와 비교하였다. 셀레늄을 다른 중금속들의 경우와 동일한 농도로 단독 첨가한 경우 SCE빈도는 $5.9{\pm}2.64$회에서 $12.3{\pm}3.99$회의 범위로 변하였고, 수은은 $6.5{\pm}2.70$회에서 $15.7{\pm}2.75$회, 카드뮴은 $6.7{\pm}2.65$회에서 $11.2{\pm}4.13$회, 크롬은 $7.0{\pm}2.58$회에서 $14.9{\pm}6.43$회의 범위로 농도증가에 비례하여 SCE빈도가 상승하였으며, 이때 세포분열지수는 공히 농도증가에 반비례하여 고농도군에서는 현저히 낮았다. 중금속들과 $1.2{mu}M$의 셀레늄을 동시에 첨가시킨 조건에서는 수은의 경우, 셀레늄과 수은의 몰(mol)농도비가 1:1, 1:2, 1:4의 조건에서, 카드뮴의 경우 1:2 및 1:4의 조건에서 SCE빈도의 현저한 감소를 나타냈으나 크롬의 경우는 셀레늄의 첨가와 무관하였으며, 세포분열지수는 전반적으로 셀레늄의 첨가에 별다른 영향을 받지 않았다.

Mercury chloride 및 Methylmercury chloride가 정상인(正常人)의 혈액배양(血液培養)에서 임파구(淋巴球)의 자매염색분체교환(姉妹染色分體交換)에 미치는 영향(影響)

고대하,Koh, Dai-Ha 대한예방의학회 1984 Journal of Preventive Medicine and Public Health Vol.17 No.1

Reciprocal exchanges of DNA in sister chromatids (SCEs) are induced by various carcinogens and mutagens, although the quantitative relationship between the number of mutations and SCEs induced varies among chemicals. Nevertheless, the analysis of SCEs production by various agents often proposed as a sensitive and quantitative assay for mutagenicity and cytotoxicity. Mercury, even if which has no evidences for mutagenicity and carcinogenicity, is reported to exert some cytotoxic effects, such as chromosomal aberrations or bad influences to ovulation and reproduction in experimental animals, etc.. In this study, tests for sister chromatid exchanges have been carried out on normal human lymphocytes in whole blood culture to add mercury chloride ($HgCl_2$) or methylmercury chloride ($CH_3\;HgCl$) for 72 hr. The results indicate the dose-dependent relationship between the frequencies of SCEs and the concentrations of $HgCl_2,\;CH_{3}HgCl$ and 5-bromo-2'-deoxyuridine (BrdU). Lymphocyte proliferation has depressed in the higher concentration of mercury.

산발적으로 신고되는 세균성이질환자의 감염원 추정을 위한 알리바이 확인 및 PCR(Polymerase Chain Reaction) 검사

고대하,윤채현,이신재,Koh, Dai-Ha,Yoon, Chai-Hyun,Lee, Sin-Jae 대한예방의학회 2005 예방의학회지 Vol.38 No.4

Objectives : A few culture-confirmed cases of S. sonnei have been notified from Korean hospitals. The source of epidemic can't be firmly determined in such cases because of the rarity of this illness in the local communities and the timing of the outbreaks. The objective of this study is to estimate the source of epidemic by investigating the patients' lifestyles. Methods : Alibi verification was used to access the presumed source of the epidemic. PCR (Polymerase Chain Reaction) was used to rapidly detect the genes of Shigella in water specimens. Results : The common lifestyle trait among the Shigella infected patients was connected with Mt. Martyr in J city, Korea. The first patient's son had gone on a pilgrimage to Mt. Martyr with 41 friends and he had only eaten rice cakes on April 5th; the second patients had visited Mt. Martyr with their mother for a picnic on April 12th; the third patient had visited Mt. Martyr with 22 friends for a pilgrimage and the patient had only drunk holy water on April 13th. Therefore, the holy water of Mt. Martyr was reckoned to be the source of the epidemic. PCR detected the genes of Shigella two days before the S. sonnei was confirmed. Conclusion : The patients' lifestyles for 7 days before the onset of symptoms should be determined in terms of time, place and contacted people to find the source of infection when cases with food poisoning are seen in the hospital setting.

RAW264.7 세포를 이용한 수은의 세포독성기전 및 수은에 대한 셀레늄의 방어기전에 대한 연구

고대하(Dai Ha Koh),김준연(Jun Youn Kim),염정호(Jung Ho Youm) 한국환경보건학회 1999 한국환경보건학회지 Vol.25 No.1

In present study, we elucidated the protective effects of selenium against the cytotoxic1ty of mercurial compounds(CH₃HgCl, HgCl₂) in RAW 264.7 cell and peritoneal macrophages from Balb/c mice. Mercurial compounds significantly decreased the cell viability and the synthesis of nitric oxide(NO) and cellular ATP in a dose-dependent manner. Selenium was not toxic at concentrations of 1-10 μM. But, selenium by itself was decreased the cell viability and the syntheses of NO and cellular ATP in dose-dependent manner above 20 μM conditions. However, in the selenium added conditions, the mercurial-induced cytotocixity was not observed. The protective effects of selenium against the cytotoxicity of mercurial compound depended on the concentration of added selenium to the culture conditions. We evaluated the mechanisms of protective effect of selenium against the mercury-induced cytotoxicity by the pretreatment experiments. In the selenium pretreatment, mercurial compounds still decreased the cell viability and the syntheses of NO and cellular ATP in a dose-dependent manner. These results indicated that the protective effect of selenium against the cytotoxicity of mercurial compounds was achieved by formation of some complex as such as SeHg or Se-Hg-protein. Though its mechanism was not clear, the protective role of selernium against the mercury toxicity would be exhibited in the immunological system.

수은에 의한 EMT-6 세포의 $NO_2^-$ 및 ATP 생성

오경재,고대하,염정호,Oh, Gyung-Jae,Koh, Dai-Ha,Youm, Jung-Ho 대한예방의학회 1996 예방의학회지 Vol.29 No.3

수은이 세포성 면역반응에 미치는 효과와 그 기전을 밝히기 위해 cytokine-EMT-6 cell-NO 모형에 대조군에는 수은을 첨가하지 않았고 나머지 실험군에는 $0.05-0.8{\mu}M$의 mercury chloride를 처리하였다. 그리고 배양시간별, 수은농도별로 세포생존율, 세포성 면역의 지표인 NO를 nitrite로 간접정량하고 대사과정에 필수 에너지요소인 nitrite를 측정한 결과는 아래와 같이 요약된다. 1. EMT-6세포의 세포생존율은 대조군과 36시간째 $0.8{\mu}M(89.50%)$을 제외한 모든 수은첨가군에서 모두 90%이상의 값을 나타내었으며, 배양시간 및 첨가한 수은농도별 군간 차이는 없었고 모든 수은첨가군과에서 대조군에 비해 큰 차이가 없었다. 2. 수은에 노출된 EMT-6 세포의 nitrite 생성량 및 ATP생성량은 배양시간의 경과에 따라 전반적으로 증가하였으며 시간경과에 따른 nitrite 생성량과 ATP 생성량은 첨가한 수은농도의 변화에 따라 각 군간에 현저한 차이를 보였다. 그리고 시간경과의 영향을 보정한 상태에서도 첨가한 수은농도의 변화에 따라 각 군간 차이는 모두 현저하게 나타났다. 한편, Nitrite 생성량과 ATP 생성량은 둘 다 수은첨가군 모두에서 대조군의 값에 비해 현저하게 낮았고, 첨가된 수은농도와 nitrite 생성량 및 ATP 생성량 사이에는 높은 음의 상관관계가 있어 수은농도의 증가에 따라 용량-반응의 관계(dose-dependent)로 감소하는 경향을 보였다. 이상의 결과, 배양조건에 수은의 첨가로 인하여 nitrite 생성량과 ATP 생성량이 동시에 감소하는 바, 수은에 의한 세포성 면역의 저하는 면역세포의 NO 생성량의 감소에 의한 것으로 사료되며, 이는 수은이 세포내 에너지생산에 관련된 대사과정을 억제시키므로 나타나는 결과라고 판단된다. Effect or mercury chloride on the synthesis or $NO_2^-$ and ATP were observed in EMT-6 cells which were cultured with cytokines$(IL-1\alpha\;and\;IFN-\gamma)$ and various concentrations of mercury chloride from 0.05 to $0.8{\mu}M$. Viability of EMT-6 cells were observed above 90% in almost groups. There were not significant differences in the viability between mercury supplemented groups and control group. It suggests viability of EMT-6 cells were not influenced by these concentrations of mercury chloride. Results of the synthesis of nitrite showed significant time and group effect. There is a significant interaction effect between concentration of mercury chloride and culture time. The effect of various concentration of mercury chloride is not the same for all levels of culture time. There were significant differences in the synthesis of nitrite between mercury chloride supplemented groups and control group, and the synthesis of nitrite in EMT-6 cell by the supplement of mercury chloride was significantly decreased in a dose-dependent manner. Results of the synthesis of ATP showed a significant group effect, and the time main effect and the $Group{\times}Time$ interaction were also significant. There were significant differences in the synthesis of ATP between mercury chloride supplemented groups and control group, and the synthesis of ATP in EMT-6 cell by the supplement of mercury chloride was significantly decreased in a dose - dependent manner. These results suggest that the disorder of cell mediated immunity by mercury chloride could be related to the inhibition of nitric oxide synthesis which will be caused by the decreased synthesis of ATP.

수은에 의한 마우스의 면역반응 조절장애

기노석,고대하,김종서,이정상,김남송,이황호,Ki, No-Suk,Koh, Dai-Ha,Kim, Chong-Suh,Lee, Jung-Sang,Kim, Nam-Song,Lee, Hwang-Ho 대한예방의학회 1994 Journal of Preventive Medicine and Public Health Vol.27 No.1

수은($HgCl_2$)이 마우스의 면역계에 미치는 영향을 밝히고자 Balb/c 마우스를 대상으로 시험관내 및 생체내 단계적 시험을 실시하였다. Lipopolysaccharide, pokeweed mitogen 및 phytohemagglutinin 등의 미토겐(mitogen)에 대한 비장세포의 반응성은수은농도에 의존적으로 억제되었다. 수은에 의한 비장세포의 증식반응억제는 배양기간 중 수은 노출시기에 관계 없었으며 수은 전처치에 의해서도 그 증식반응은 억제되었다. 그러나 수은은 pokeweed mitogen으로 유도한 비장세포의 항체생산은 항진시켰다. 실험동물을 음용에 의하여 수은에 3주간 노출시켰을 때 투여기간 중 체중의 증가는 현저히 둔화되었으나, 흉선 및 비장의 무게, 신장, 골수, 비장 및 슬와 림프절의 병리학적 변화는 유발되지 않았다. 그러나 혈청 면역 글로불린(immunoglobulin) 농도는 현저히 증가되었다. 증가된 혈청 $IgG_1$및 IgE농도는interleukin-4 (IL-4)에 대한 항체투여로 현저히 감소되었다. 수은투여 마우스의 면양적혈구(SRBC)에 대한 항체반응을 측정한 결과 면양적혈구에 대한 총응집소가에는 대조군의 그것과 차이가 없었으나 혈청 IgM 및 IgG농도는 오히려 대조군의 그것보다 현저히 높았다. 이상의 성적들은 수은의 면역계에 대한 독작용은 그 측정방법에 따라 다를 수 있으며, 수은노출에 따른 림프조직의 병변이 발생하기 전에 면역계의 기능적 변화가 일어나고, 수은에 의한 혈청 면역 글로불린 농도의 증가는 특정항원에 대한 항체반응과는 무관할 수 있는 등 수은이 면역반응에 이상을 초래함을 시사한다. The studies reported here were undertaken to investigate the effects of mercury chloride on immune system of Balb/c mouse employing a flexible tier of in vitro and in vivo assays. Mercury chloride inhibited the proliferative responses of spleen cells to lipopolysaccharide, pokeweed mitogen, and phytohemagglutinin as a dose-dependent manner. This inhibitory effect was observed not only when $HgCl_2$ was added 2nd or 3rd day of 3 days culture period but also when spleen cells was pretreated with $HgCl_2$ for 2 hours. Mercury chloride, however, potentiated the production of IgM and IgG from spleen cells. During the $HgCl_2$ administration by drinking for 3 weeks, the weight gain of mice was significantly blunted than that o control group mice, while no overt signs related to mercury toxicity were noted in any mice of experimental group. There was no change in thymus and spleen weights, and in histological findings of kidney, bone marrow of femur, thymus, spleen, and popliteal lymph node after 3 weeks of mercury exposure. However, $HgCl_2$ induced a significant increase of total serum IgM, IgG including $IgG_1,\;IgG_{2a}\;and\;IgG_{2b}$, and IgE in Balb/c mice. Treatment in vivo with anti-IL-4 monoclonal antibody significantly abrogated the $HgCl_2$-induced increase in total serum IgG1 and IgE. Whereas $HgCl_2$ potentiated total serum IgM and IgG, there was no difference in total serum hemagglutinin to SRBC (Sheep Red Blood Cell) between experimental and control group mice when these mice were immunized with SRBC. All these findings observed in Balb/c mice suggest that mercury perturbates well-orchestrated regulation of immune responses before developing histopathological changes in lymphoid tissues.

Mercury Chloride가 마우스 복강대식세포 및 EMT-6 세포의 Nitric Oxide 생성에 미치는 영향

권근상,고대하,기노석,염정호,Kwon, Keun-Sang,Koh, Dai-Ha,Ki, No-Suk,Youm, Jung-Ho 대한예방의학회 1997 Journal of Preventive Medicine and Public Health Vol.30 No.2

Balb/c 마우스의 복강대식세포와 동종 마우스의 유선암에서 기원한 EMT-6 세포를 배양하는 조건에 여러 농도의 수은을 첨가하여 nitrite와 nitrite 생성의 변화를 관찰한 결과는 다음과 같다. 복강대식세포 및 EMT-6 세포가 생성하는 nitrite와 nitrate 양은 공히 배양시작 12시간 후에 생성량에 비해 24 시간 후에는 2배, 36시간 후에는 3배의 농도로 측정되었다. 이때 nitrite와 nitrate 농도 사이에 매우 밀접한 상관관계가 관찰되었다. 수음첨가에 따라 nitrite 및 nitrate 생성량은 용량 의존적 관계로 현저한 감소를 보이며, 24 시간 또는 36시간 후의 세포생존률도 역시 수은농도에 비례하여 감소되는데, 복강대식세포의 생존률 감소가 EMT-6 세포의 것에 비해 더욱 현저하였다. 이들 세포내에서 생성되는 ATP의 양은 복강세포의 경우 그 생존률과 비례하는 경향이었으나, EMT-6세포의 경우는 비교적 높은 생존률에도 불구하교 배양액내에 수은농도를 증가시킴에 따라 ATP생산은 현저히 감소하였다. 이상의 결과는 면역세포인 복강대식세포 뿐아니라 암세포인 EMT-6 세포에서도, L-arginine으로부터 nitric oxide를 생성하는 생화학적 반응이 수은에 의해 공히 억제될 수 있음을 보여준다. 한편 수은의 세포성 면역에 미치는 독성은 수은이 면역세포의 ATP생성과 관련한 에너지 대사과정의 장애을 초래하여 nitric oxide 생성에 필요한 반응에너지의 공급을 억제시키기 때문에 나타나는 현상으로 사료된다. The effects of treatment with mercury chloride on the nitrite and nitrate syntheses were observed in peritoneal macrophages from Balb/c mice and EMT-6 cells in vitro. The cells were cultured in Dulbecco's modified Eagle's medium(DMEM) with cytokines. Amounts of nitrite and nitrate in the culture media after 24 and 36 hours of culture were about 2-fold, and 3-fold of those measured after 12 hours respectively. There were very close associations Between the amounts of nitrite and nitrate measured in the culture media according to culture time. The survival rate of peritoneal macrophages was significantly decreased by mercury chloride added into the media in dose-dependent manner, however the survivals of EMT-6 cells were not influenced by mercury chloride concentration in media. Nitrite and nitrate syntheses were dose-dependently decreased by mercury chloride added in culture media. ATP synthesis also decreased in EMT-6 cells by mercury chloride. These results reported here suggest that the disorder of cell mediated immunity by mercurials could be related to the inhibition of nitric oxide synthesis which seems to be caused by the inhibition of ATP synthesis.

건강한 남성에서 혈중 감마지티피 수준과 공복혈당장애 (IFG)의 발생 위험도: 2년 추적 연구

신주연,임종한,고대하,권근상,김용규,김환철,이의철,이주형,남문석,홍성빈,박신구,Shin, Joo-Youn,Lim, Jong-Han,Koh, Dai-Ha,Kwon, Keun-Sang,Kim, Yong-Kyu,Kim, Hwan-Chul,Lee, Yeui-Cheol,Lee, Ju-Hyoung,Nam, Moon-Suk,Hong, Sung-Bin,Park, Shin 대한예방의학회 2006 예방의학회지 Vol.39 No.4

Objectives: An increase in the serum gamma-glutamyltransferase (GGT) concentration has been regarded as a marker of alcohol drinking or liver disease. Some reports, however, have suggested that the serum GGT may be a sensitive and early biomarker for the development of prediabetes and diabetes. In this study we investigated whether serum GGT is a reliable predictor of the incident impaired fasting glucose (IFG), including diabetes. Methods: We performed a prospective study for two years (2002-2004). We analyzed the periodic health examination data from a total of 4,711 men. The examinations were done in the years 2002 and 2004. The analyzed data included a self-questionnaire, a physical examination and the laboratory results. Both IFG and diabetes were defined as a serum fasting glucose concentration of more than 100 mg/dL and 126 mg/dL, respectively. Results: A total of 738 cases (15.7%) of incident IFG and 13 cases (0.3%) of diabetes occurred. The mean serum GGT concentrations were quite different between the normal (38.0 IU) and incident IFG groups (50.3 IU), and the incident diabetes group (66.0 IU) (p<0.001). After multivariable adjustment, the relative risks for incident IFG or diabetes across the baseline GGT categories (<10th, 10th-20th, 30th-40th, 50th-60th, 70th-80th and >90th percentile) were 1.0, 1.172 (0.769-1.785), 1.107 (0.725-1.689), 1.444 (0.934-2.232), 2.061 (1.401-3.031) and 2.545 (1.784-3.631) (p-value for trend: <0.001). The risks significantly increased with increasing levels of GGT for 2 years; when comparing the increased groups (<10%, 10-20%, >20%) versus the decreased over 20% group of GGT, the risks for IFG or diabetes were 1.334 (1.002-1.776), 1.613 (1.183-2.199) and 1.399 (1.092-1.794). Conclusions: Our findings suggest that serum GGT concentrations within its normal range may be an early predictor of the development of IFG and diabetes. As serum GGT is a relatively inexpensive test and a reliable marker, it might have important implications in public health promotion.

수은 및 카드뮴의 세포독성에 대한 Glutathione의 역할에 관한 연구

정재호,김준연,고대하,Jeong, Jae-Ho,Kim, Jun-Youn,Koh, Dai-Ha 대한예방의학회 1999 예방의학회지 Vol.32 No.2

본 연구는 EMT-6 세포를 이용하여 무기수은, 유기수은 및 카드뮴의 세포독성에 대한 glutathione(GSH)의 방어효과를 알아보고자 하였다. 무기수은, 유기수은 및 카드뮴을 첨가한 배양조건에서 EMT-6 세포의 세포생존율, ${NO_2}^-$ 및 ATP 생성량은 첨가한 중금속의 농도가 증가할수록 용량의존적으로 감소하였다. GSH, OTC 및 BSO를 단독 첨가한 배양조건은 세포의 세포생존율과 NO2- 및 ${NO_2}^-$ 생성량에 영향을 주지 않았다. 수은화합물 및 카드뮴과 GSH를 동시 첨가한 배양조건에서는 세포생존율이 90% 이상 유지되었고, ${NO_2}^-$ 및 ATP 생성량은 기본배양조건과 비슷한 수준으로 나타났다. $16{\mu}M$의 무기 및 유기수은과 $160{\mu}M$의 카드뮴을 첨가한 실험조건에 GSH를 동시 첨가했을 경우 방어효과는 GSH의 농도에 따라 용량의존적으로 증가하였다. 세포내에서 수은 및 카드뮴의 세포독성에 대한 GSH역할을 알아보고자 GSH, OTC, BSO 전처리 실험을 한 결과, GSH의 전처리는 이들이 세포막을 통과하지 못하기 때문에 대조군과 비슷한 양상으로 나타난 반면에 BSO를 전처리한 군에서는 세포내 GSH 농도의 감소로 수은의 세포 독성이 증가하여 대조군에 비하여 ${NO_2}^-$와 ATP 생성량이 현저히 감소하였다. 또한 세포내 GSH의 농도를 증가시키는 OTC를 전처리한 결과 수은의 독성에 대한 방어효과가 시간 및 용량 의존적으로 현저하게 증가하였다. 이러한 실험결과는 수은의 세포독성에 대한 GSH의 방어효과가 GSH 세포내 농도와 밀접한 관련이 있음을 간접적으로 보여주고 있다. 본 연구의 결과는 수은 및 카드뮴의 독성에 대한 GSH의 방어작용이 단순히 -SH기와 중금속의 결합에 의한 결과가 아니라 세포내에서 GSH 분자가 갖는 고유의 기능으로 판단되며, 특히 중금속에 의한 에너지대사의 장애를 GSH가 회복시킬 수 있음을 보여준다. Objectives: To evaluate the protective effects of glutathione (GSH) on the cytotoxicity of mercurial compounds$(CM_3HgCl,\;HgCl_2)$ or cadmium chloride$(CdCl_2)$ in EMT-6 cells. Methods: The compounds investigated were $CH_3HgCl,\;HgCl_2,\;CdCl_2$, GSH, buthionine Sulfoximine(BSO), L-2-oxothiazolidine-4-carboxylic acid(OTC). Cytotoxicity analysis consist of nitric oxide(NO) production, ATP production and cell viability. Results: Mercurial compounds and cadmium chloride significantly decreased cell viability and the synthesis of NO and cellular ATP in EMT-6 cells. GSH was not toxic at concentrations of 0-1.6 mM. In the presence of GSH, mercurial compounds and cadmium did not decrease the production of ATP and nitrite in EMT-6 cells. The protective effects of GSH against the cytotoxicity of mercurial compounds and cadmium depended on the concentration of added GSH to the culture medium for EMT-6 cells. We evaluated the effects of intracellular GSH level on mercury- or cadmium-induced cytotoxicity by the pretreatment experiments. Pretreatment of GSH was not changed ${NO_2}^-$ and ATP production, and pretreatment of BSO was decreased in dose and time-dependent manner. Pretreatment of OTC was increased ${NO_2}^-$ and ATP production in dose- and tine-dependent manner. Because intracellular GSH level was increased by OTC pretreatment, the protective effect on mercury- and cadmium-induced cytotoxicity was increased. Conclusions: These results indicated that sulfhydryl compounds had the protective effects against mercury-induced cytotoxicity by the intracellular GSH levels.