• Toxicological Research
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• v.22 no.1
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• pp.9-13
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• 2006

Diesel exhausted particles (DEP), a kind of fine particles with aerodynamic diameters less than $2.5{\mu}m$ (PM2.5), is of great concern to human health because they remain in atmosphere for long periods, invade an indoor air environment, and can be breathed most deeply into lung and reached the alveoli because of their small size ($0.1{\sim}0.4\;{\mu}m$ in diameter). Epidemiological and experimental studies suggested that DEP may play an active role in the increased respiratory mortality and morbidity. In addition to their physical characteristics, the chemical components including polyaromatic hydrocarbon (PAH) are regarded as a carcinogen causing pulmonary tumors. PLD plays an important role in cell proliferation with various physiological phenomena and affects other enzymes by activating signal transduction pathway. We investigated the cytotoxic mechanism of DEP on RAW 264.7 cells focusing on the role in activation of PLD. Our results suggested DEP induced PLD activity through a specific signaling pathway involving phospholipase $A_2$, PLC, PKC and $Ca^{2+}$ mobilization.

• CELLMED
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• v.2 no.4
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• pp.35.1-35.11
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• 2012

The homeopathic remedy Chelidonium majus 200C (Chel-200) is traditionally used by homeopathic practitioners in liver ailments arising out of hepatotoxicity. The present investigation was aimed at examining whether vitamin C (L-ascorbic acid or AA), used in both traditional and orthodox medicines, can show better effects when used in combination with Chel-200, in favorably modifying the toxicological effects induced by the chronic feeding of p-dimethylaminoazobenzene (p-DAB, initiator) and phenobarbital (PB, promoter) in mice for 7 days through 120 days to induce hepatotoxicity and liver tumors. Mice were euthanized at 7, 15, 30, 60, 90, and 120 days of carcinogen feeding to assess various cytogenetical, biochemical and histological changes occurring in them. In a placebo controlled study, Chel-200 or the respective placebo (Alcohol-200C or Alc, "vehicle" of homeopathic drug), was orally administered to toxicant-fed mice. Sub-groups of the mice receiving Chel-200 were also fed either AA or an Alc placebo and their individual and conjoint effects were studied against the respective controls, to evaluate if the combination therapy of Chel-200 with AA can be of additional help in the amelioration of the toxicities generated by the toxicants. The combined feeding of Chel-200 and AA appeared to reduce the cytotoxic and genotoxic effects significantly, when compared to either only the Chel-200 or AA fed group. A similar trend was also obtained in the results of scanning and transmission electron microscopic studies of the livers. Experiments in other mammalian models are warranted to confirm if these drugs in combination could be used in palliative care of human patients with liver diseases including cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3409-3416
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• 2012

Aim: It is well known that polycyclic aromatic hydrocarbons (PAHs) such as benzo (a) pyrene have carcinogenic properties and may cause many types of cancers in human populations. Genetic susceptibility might be due to variation in genes encoding for carcinogen metabolizing enzymes, such as cytochrome P-450 (CYP450). Our study aimed to investigate the effect of genetic polymorphisms of CYP1A1 (m1 and m2) on genetic damage in 115 coal-tar workers exposed to PAHs at their work place. Methods: Genetic polymorphisms of CYP1A1 were determined by the PCR-RFLP method. Comet and buccal micronucleus assays were used to evaluate genetic damage among 115 coal tar workers and 105 control subjects. Results: Both CYP1A1 m1 and CYP1A1 m2 heterozygous and homozygous (wt/mt+mt/mt) variants individually as well as synergistically showed significant association (P<0.05) with genetic damage as measured by tail moment (TM) and buccal micronuclei (BMN) frequencies in control and exposed subjects. Conclusion: In our study we found significant association of CYP1A1 m1 and m2 heterozygous (wt/mt)+homozygous (mt/mt) variants with genetic damage suggesting that these polymorphisms may modulate the effects of PAH exposure in occupational settings.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3413-3418
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• 2015

Background: Liver fluke infection caused by the parasite Opisthorchis viverrini (O. viverrini), a human carcinogen, is endemic in north-eastern Thailand and remains a major health problem. Objectives: The objectives of the study were to (1) resurvey the prevalence of O. viverrini infection in a field site from the Khon Kaen Cohort Study (in newly recruited subjects as well as previous cohort subjects surveyed in 1992); (2) investigate how subjects' lifestyle habits and their exposure to health promotion initiatives influence changes in prevalence of O. viverrini infection. Materials and Methods: The prevalence of O. viverrini infection in the cohort subjects (as well as new subjects) was investigated using faecal egg counts. Information on demographic factors, lifestyle and awareness of health promotion initiatives were obtained through questionnaires. Results: O. viverrini infection rates in the same individuals of the cohort were lower in 2006 than in 1992. Also, by studying the period effect, the current 35-44 year olds had a 12.4% (95% CI 3.9% to 20.9%) lower prevalence of O. viverrini infection than the 35-44 year olds in 1992 (24.2% versus 11.8%). Lifestyle choices showed that smoking and alcohol consumption were associated with an increased chance of acquiring O. viverrini infection with adjusted odds ratios of 10.1 (95%CI 2.4-41.6) and 5.3 (95%CI 1.2-23.0), respectively. Conclusions: Our study has demonstrated that although the prevalence of O. viverrini infection over a 14-year period has decreased, unhealthy lifestyle was common with smoking and alcohol consumption being associated with increased chances of infection, emphasising the double burden of disease which developing countries are facing.

• Parasites, Hosts and Diseases
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• v.50 no.4
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• pp.309-315
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• 2012

Clonorchis sinensis is a biological carcinogen inducing human cholangiocarcinoma, and clonorchiasis is one of the important endemic infectious diseases in East Asia. The present study investigated survival longevity of C. sinensis adult worms in various in vitro conditions to find the best way of keeping the worms longer. The worms were maintained in 0.85% NaCl, 1${\times}$PBS, 1${\times}$Locke's solution, RPMI-1640, DMEM, and IMDM media, and in 1${\times}$Locke's solution with different supplements. All of the worms died within 3 and 7 days in 0.85% NaCl and 1${\times}$PBS, respectively, but survived up to 57 days in 1${\times}$Locke's solution. The worms lived for 106 days in DMEM, and 114 days in both RPMI-1640 and IMDM media. The survival rate in RPMI-1640 medium was the highest (50%) compared to that in DMEM ($20{\pm}10%$) and in IMDM ($33.3{\pm}25.2%$) after 3 months. The 1${\times}$Locke's solution with 0.005% bovine bile supplement showed increased duration of maximum survival from 42 days to 70 days. Higher concentration of bile supplements than 0.005% or addition of glucose were disadvantageous for the worm survival. The worms died rapidly in solutions containing L-aspartic acid, L-glutamic acid, and adenine compared to L-arginine, L-serine, and L-tryptophan. In conclusion, the 1${\times}$Locke's solution best supports the worms alive among inorganic solutions for 57 days, and the RPMI-1640 medium maintains living C. sinensis adults better and longer up to 114 days in vitro than other media.

• Korean Journal of Pharmacognosy
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• v.32 no.2 s.125
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• pp.163-167
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• 2001

Prunella vulgaris L. aqua-acupuncture solution (PVAS) was tested for cancer chemopreventive activity using chemoprevention-associated biochemical end points. The following effects were measured. : (a) inhibition of 7,12-dimethylbenz[a]anthracene (DMBA)-induced cytochrome P4501A1 activity (b) inhibition of $[^3H]B[a]P-DNA$ binding (c) inhibition of phorbol 12-myristate 13-acetate (TPA)-induced free radical formation in HL-60 cells (d) inhibition of polyamine metabolism. PVAS inhibited cytochrome P4501A1-mediated ethoxyresorufin-O-deethylase activity. The binding of $[^3H]B[a]P$ metabolites to DNA of NCTC-clone 1469 cells was inhibited significantly by PVAS. There is 22% inhibition of TPA-induced free radical formation in human leukemic cells with 5 mg/ml PVAS. Proliferation of Acanthamoeba castellanii was inhibited by PAVS at concentration of 30 mg/ml. PAVS positive in these assays may inhibit the carcinogenesis process and is considered very promising cancer-preventing agent because of its multiple activities.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.256-262
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• 2014

Objectives: The purpose of this study was to identify the major volatile organic compounds generated during extrusion work with nylon 66 resin and evaluate causes of discomfort among extrusion workers. Methods: A thermal decomposition experiment using nylon 66 resin collected at a worksite was conducted in the laboratory. Based on hazards identified through the thermal decomposition experiment, the exposure levels of the workers were evaluated. Results: The major decomposition products were formaldehyde, acetaldehyde, aniline, cyclopentanone and diphenyl amine. These materials were identical to those sampled in the extrusion booth. The sources of the annoying smells, about which the workers had complained, were formaldehyde, aniline, diphenyl amine, and other hazards in the vapor and fine particles produced by the extrusion work. Formaldehyde, acetaldehyde, and aniline were detected from air samples among workers involved in extrusion work. However, the concentration levels were much lower than Korean occupational exposure limits. The average concentration levels of formaldehyde, acetaldehyde, and aniline were 0.0120 ppm, 0.0036 ppm and 0.0006 ppm, respectively. Conclusions: The extrusion process at around $300^{\circ}C$ thermally decomposes the nylon 66 resin, emitting formaldehyde, aniline, and other hazards, which might have made workers uncomfortable due to their smells. The workers exposure levels to volatile organic compounds were far lower than Korean occupational exposure limits. However, since formaldehyde is a human carcinogen and acetaldehyde and aniline are also confirmed animal carcinogens, it is recommended that exposure levels should be maintained at a minimum level.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.5
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• pp.364-371
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• 2002

Many chemical compopunds are converted into reactive electrophilic metabolites by the oxidative(Phase I) enzymes, which are mainly cytochrome P-450 enzyme(CYPs). Phase II conjugating enzymes, such as glutathione S-transferase(GST), usually act as inactivation of enzymes. Genetic polymorphisms have been found to be associated with increased susceptibility to cancer of the lung, bladder, breast and colorectal. Many of the polymorphic genes of carcinogen metabolism show considerably different type of cancer among different ethnic groups as well as individuals within the same group. The aim of this study is (1) to establish the frequencies of genetic polymorphisms of GSTM1 and CYP1A1 in Korean oral squamous cell carcinoma(SCC), (2) to associate oral SCC with the risk of these genetic polymorphisms. The genetic polymorphisms of the GSTM1 and the CYP1A1 genes among 50 Korean oral SCC were analyzed using polymerase chain reaction(PCR). The results suggest that the homozygote and the mutant type of CYP1A1 MspI polymorphisms may be associated with genetic susceptibility to oral SCC in Korean. A combination of the GSTM1 null type with the homozygote(m1/m1), and the mutant(m2/m2) type of CYP1A1 MspI polymorphisms showed a relatively high risk of oral SCC in Korean. In the smoking group, the GSTM1 wild genotype may be the high risk factor of oral SCC in Korean. These data coincide with the hypothesis which states that different susceptibility to cancer of genetic polymorphisms exist among different ethnic group and different types of human cancer.

• Progress in Superconductivity and Cryogenics
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• v.20 no.2
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• pp.1-5
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• 2018

Arsenic (As) is one of the elements having most harmful impact on the human health. Arsenic is a known carcinogen and arsenic contamination of drinking water is affecting on humans in many regions of the world. Adsorption has been proved most preferable technique for the removal of arsenic. Many researchers have studied various types of solid materials as arsenic adsorbent, and iron oxide and its modified forms are considered as the most effective adsorbent in terms of adsorption capacity, recovery, and economics. However, most of all iron oxides have small surface area in comparing with common adsorbents in environmental application such as activated carbon but the activated carbon has weak sorption affinity for arsenic. We have used an activated carbon as base adsorbent and iron oxide coating on the activated carbon as high affinity sorption sites and giving magnetic attraction ability. In this study, adsorption properties of arsenic and magnetic separation efficiency of the magnetized activated carbon (MAC) were evaluated with variable iron oxide content. As the iron oxide content of the MAC increased, adsorption capacity has also gradually increased up to a point where clogging by iron oxide in the pore of activated carbon compensate the increased sorption capacity. The increase of iron oxide content of the MAC also affected magnetic properties, which resulted in greater magnetic separation efficiency. Current results show that magnetically modified common adsorbent can be an efficiency improved adsorbent and a feasible environmental process if it is combined with the magnetic separation.

• Journal of Environmental Science International
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• v.16 no.3
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• pp.323-331
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• 2007

Polycyclic aromatic hydrocarbons (PAHs) are well known for strong carcinogen. However, the human exposure analysis of PAHs is quite difficult and unreliable because of hard for estimation of actual expose dose. Then urinary 1-hydroxypyrene (1-OHP) has been a biological marker of exposure to PAHs. The purpose of this study was to investigate total amount from exposure to PAHs soused by indoor occupational exposure, and residence at Seoul metropolitan area and Kyeonggi province in Korea. Thirty-five housewives were included in this study from April 2003 through February 2004. Dietary habit and general characteristics such as age, type of building, existence of passive smoking, period of residence, fuel type for heating and ventilation type were obtained by self administered questionnaire. Urine samples were collected at morning and freeze quickly. Urinary creatinine was measured for converting into 24 hr urine. Concentration of the indoor PAHs was examined by NIOSH method number 5506. Urinary 1-OHP and PAHs were analysed by HPLC. Correlation coefficient between urinary 1-OHP levels and pyrene concentration of indoor air was 0.66 and statistically significant(P<0.01). The difference of urinary 1-OHP level due to dietary habits were not significant. Urinary 1-OHP level of Spring, Summer, Autumn, and Winter were $0.21{\pm}0.12,\;0.10{\pm}0.17,\;0.16{\pm}0.12,\;0.17{\pm}0.14{\mu}g/g$ cr, respectively. The arithmetic means of urinary 1-OHP for four season tee $0.16{\pm}0.14 {\mu}g/g$ cr. There was a trend that urinary 1-OHP level of residents who dwelling in apartment were higher compared with detached home, Comparison of 1-OHP level between heating by kerosene and LPG, Much higher gas heating type than kerosene type (P<0.05). This result implies that the urinary 1-OHP can be applied as the PAHs exposure indices.