Geonotoxicity study of illegal drug MDMA and its nitroso derivative N-MDMA by micronucleus and chromosomal aberration tests using Chinese hamsger lung fibroblast cell line

<p><b>OBJECTIVES</b>An increase in incidence of the illegal use of tablets containing 3,4-methylenedioxymethamphetamine hydrochloride (MDMA) has recently become a widespread social problem. MDMA ingested orally reacts with nitrite in the stomach and is synthesized intoN-nitroso-3,4-methylenedioxymethamphetamine (N-MDMA). The aim of this study is to investigate the genotoxic effects of MDMA and N-MDMA on the basis of the results of an in vitro micronucleus (MN) test and an in vitro chromosomal aberration (CA) test using a Chinese hamster lung fibroblast cell line (CHL/IU).</p><p><b>METHODS</b>Tablets containing MDMA obtained from the Regional Bureau of the Ministry of Health, Labor and Welfare were purified, and N-MDMA was synthesized from MDMA in our laboratory. To evaluate the effects of MDMA and N-MDMA, the MN test established by our laboratory and the CA test in accordance with the guidelines for toxicity studies of drugs recommended by the Ministry of Health, Labor and Welfare were performed.</p><p><b>RESULTS</b>In the MN test, no increased frequency of MNs was not found for MDMA. On the other hand, an apparently increased frequency of MNs was observed for N-MDMA. In the CA test, no CA was found for MDMA, but CA was observed for N-MDMA apparently.</p><p><b>CONCLUSION</b>N-MDMA genotoxicity was observed in the MN and CA tests. However, no MDMA genotoxicity was observed.</p>

Genotoxicity Study of Illegal Drug MDMA and Its Nitroso Derivative N-MDMA by Micronucleus and Chromosomal Aberration Tests using Chinese Hamster Lung Fibroblast Cell Line

Objectives: An increase in incidence of the illegal use of tablets containing 3,4-methylenedioxymethamphetamine hydrochloride (MDMA) has recently become a widespread social problem. MDMA ingested orally reacts with nitrite in the stomach and is synthesized into N-nitroso-3,4-methylenedioxymethamphetamine (N-MDMA). The aim of this study is to investigate the genotoxic effects of MDMA and N-MDMA on the basis of the results of an in vitro micronucleus (MN) test and an in vitro chromosomal aberration (CA) test using a Chinese hamster lung fibroblast cell line (CHL/IU). Methods: Tablets containing MDMA obtained from the Regional Bureau of the Ministry of Health, Labor and Welfare were purified, and N-MDMA was synthesized from MDMA in our laboratory. To evaluate the effects of MDMA and N-MDMA, the MN test established by our laboratory and the CA test in accordance with the guidelines for toxicity studies of drugs recommended by the Ministry of Health, Labor and Welfare were performed. Results: In the MN test, no increased frequency of MNs was not found for MDMA. On the other hand, an apparently increased frequency of MNs was observed for N-MDMA. In the CA test, no CA was found for MDMA, but CA was observed for N-MDMA apparently. Conclusion: N-MDMA genotoxicity was observed in the MN and CA tests. However, no MDMA genotoxicity was observed.

Genotoxic effects of N-nitrosoketamine and ketamine as assessed by in vitro micronucleus test in Chinese hamster lung fibroblast cell line

<p><b>OBJECTIVES</b>Ketamine hydrochloride (KT) is a secondary amine that has been safely used as an injectable anesthetic and analgesic to avoid the production of nitroso compounds in the stomach. However, ketamine in the tablet form has recently become an abused, recreational drug. The aim of this study was to investigate the genotoxic effects of N-nitrosoketamine (NKT) and KT on the basis of an in vitro micronucleus (MN) test using a Chinese hamster lung fibroblast cell line (CHL/IU).</p><p><b>METHODS</b>NKT was synthesized from KT in our laboratory. In the MN tests, CHL/IU cells were continuously treated with either NKT or KT for 24, 48, or 72 hours without the S9 mix. The cells were also treated with NKT or KT with or without the S9 mix for 6 hours, followed by a recovery period of 18, 42, or 66 hours (short-term treatment). The results were considered to be statistically significant when the p-values of both Fisher's exact test and the trend test were less than 0.05.</p><p><b>RESULTS</b>After the short-term treatment with either NKT or KT with and without the S9 mix, the frequency of micronuclei significantly increased. However, the frequency of micronuclei did not significantly increase after the continuous treatment with either NKT or KT. Both NKT and KT were determined to be genotoxic in the short-term treatment with or without the S9 mix, but they were determined to be nongenotoxic in continuous treatment.</p><p><b>CONCLUSION</b>Our findings suggest that NKT has a stronger genotoxic effect than KT.</p>

Effect of static magnetic field on the induction of micronuclei by some mutagens

<p><b>OBJECTIVES</b>It is important to assess the risk of static magnetic fields (SMFs) on human health, because epidemiological studies have indicated that SMFs play a role in the development of diseases such as leukemia and brain tumor. In our environment, we have numerous chances to be exposed to not only SMFs but also many chemicals containing mutagens. The aim of this study is to investigate the effect of SMFs on the induction of micronuclei induced by some mutagens.</p><p><b>METHODS</b>BALB/c mice were exposed to 4.7 tesla (T) SMF for 24 hr immediately after the injection of carboquone (alkylating agent), colcemid (spindle poison), mitomycin C (cross-linking agent), vincristine (spindle poison), sodium fluoride (a byproduct of aluminum plants under strong SMF) or 1-ethyl-1-nitrosourea (brain tumor-, gliomas- and thymic lymphoma-inducing chemical).</p><p><b>RESULTS</b>The frequency of micronuclei induced by six mutagens increased after co-exposure to SMF.</p><p><b>CONCLUSIONS</b>An additive/synergistic effect of SMF and chemicals was observed from the results of increased frequency of micronuclei induced by mutagens in mouse bone marrow erythrocytes.</p>

Genotoxic Effects of \it{N}-nitrosoketamine and Ketamine as Assessed by In Vitro Micronucleus Test in Chinese Hamster Lung Fibroblast Cell Line

Objectives: Ketamine hydrochloride (KT) is a secondary amine that has been safely used as an injectable anesthetic and analgesic to avoid the production of nitroso compounds in the stomach. However, ketamine in the tablet form has recently become an abused, recreational drug. The aim of this study was to investigate the genotoxic effects of N-nitrosoketamine (NKT) and KT on the basis of an in vitro micronucleus (MN) test using a Chinese hamster lung fibroblast cell line (CHL/IU). Methods: NKT was synthesized from KT in our laboratory. In the MN tests, CHL/IU cells were continuously treated with either NKT or KT for 24, 48, or 72 hours without the S9 mix. The cells were also treated with NKT or KT with or without the S9 mix for 6 hours, followed by a recovery period of 18, 42, or 66 hours (short-term treatment). The results were considered to be statistically significant when the p-values of both Fisher's exact test and the trend test were less than 0.05. Results: After the short-term treatment with either NKT or KT with and without the S9 mix, the frequency of micronuclei significantly increased. However, the frequency of micronuclei did not significantly increase after the continuous treatment with either NKT or KT. Both NKT and KT were determined to be genotoxic in the short-term treatment with or without the S9 mix, but they were determined to be nongenotoxic in continuous treatment. Conclusion: Our findings suggest that NKT has a stronger genotoxic effect than KT.

Effect of Static Magnetic Field on the Induction of Micronuclei by Some Mutagens

Objectives: It is important to assess the risk of static magnetic fields (SMFs) on human health, because epidemiological studies have indicated that SMFs play a role in the development of diseases such as leukemia and brain tumor. In our environment, we have numerous chances to be exposed to not only SMFs but also many chemicals containing mutagens. The aim of this study is to investigate the effect of SMFs on the induction of micronuclei induced by some mutagens. Methods: BALB/c mice were exposed to 4.7 tesla (T) SMF for 24 hr immediately after the injection of carboquone (alkylating agent), colcemid (spindle poison), mitomycin C (cross-linking agent), vincristine (spindle poison), sodium fluoride (a byproduct of aluminum plants under strong SMF) or 1-ethyl-1-nitrosourea (brain tumor-, gliomas- and thymic lymphoma-inducing chemical). Results: The frequency of micronuclei induced by six mutagens increased after co-exposure to SMF. Conclusions: An additive/synergistic effect of SMF and chemicals was observed from the results of increased frequency of micronuclei induced by mutagens in mouse bone marrow erythrocytes.

The frequencies of micronuclei induced by cisplatin in newborn rat astrocytes are increased by 50-Hz, 7.5- and 10-mT electromagnetic fields

<p><b>OBJECTIVES</b>Epidemiological studies have suggested that exposure to environmental and occupational electromagnetic fields (EMFs) contribute to the induction of brain tumors, leukemia, and other neoplasms. The aim of this study was to investigate the genotoxic effects of exposure to 50-Hz EMFs. and of co-exposure to cisplatin, a mutagen and carcinogen, and 50-Hz EMFs, using an in vivo newborn rat astrocyte micronucleus assay.</p><p><b>METHODS</b>Three day-old male Sprague-Dawley rats were co-exposed to 50-Hz EMFs and 1.25 or 2.5 mg/kg of cisplatin. Brain cells were dissociated into single cells and cultured for 96 hours, then stained with acridine orange and an antibody against glial fibrillary acidic protein. The frequency of micronucleated astrocytes was counted with a fluorescent microscope.</p><p><b>RESULTS</b>The frequency of micronuclei was not increased in rat astrocytes exposed to EMFs alone. However, the frequencies of micronuclei in co-exposure to 2.5 mg/kg cisplatin and EMFs (7.5- and 10-mT) were significantly increased, compared with those in exposure to 2.5 mg/kg cisplatin alone (sham-exposure, 0-mT EMFs) for 72 hours (p<0.01).</p><p><b>CONCLUSION</b>Exposure to EMFs alone did not have a genotoxic effect but co-exposure to EMFs increased the genotoxic activity induced by cisplatin. Our findings suggest that EMFs enhance the genotoxic effects of cisplatin.</p>

The Frequencies of Micronuclei Induced by Cisplatin in Newborn Rat Astrocytes Are Increased by 50-Hz, 7.5- and 10-mT Electromagnetic Fields

Objectives: Epidemiological studies have suggested that exposure to environmental and occupational electromagnetic fields (EMFs) contribute to the induction of brain tumors, leukemia, and other neoplasms. The aim of this study was to investigate the genotoxic effects of exposure to 50-Hz EMFs, and of co-exposure to cisplatin, a mutagen and carcinogen, and 50-Hz EMFs, using an in vivo newborn rat astrocyte micronucleus assay. Methods: Three day-old male Sprague-Dawley rats were co-exposed to 50-Hz EMFs and 1.25 or 2.5 mg/kg of cisplatin. Brain cells were dissociated into single cells and cultured for 96 hours, then stained with acridine orange and an antibody against glial fibrillary acidic protein. The frequency of micronucleated astrocytes was counted with a fluorescent microscope. Results: The frequency of micronuclei was not increased in rat astrocytes exposed to EMFs alone. However, the frequencies of micronuclei in co-exposure to 2.5 mg/kg cisplatin and EMFs (7.5- and 10-mT) were significantly increased, compared with those in exposure to 2.5 mg/kg cisplatin alone (sham-exposure, 0-mT EMFs) for 72 hours (p<0.01). Conclusion: Exposure to EMFs alone did not have a genotoxic effect but co-exposure to EMFs increased the genotoxic activity induced by cisplatin. Our findings suggest that EMFs enhance the genotoxic effects of cisplatin.