Genotoxicity in fishes environmentally exposed to As, Se, Hg, Pb, Cr and toxaphene in the lower Colorado River basin, at Mexicali valley, Baja California, México.

The environmental exposure to As, Se, Hg, Pb, Cr and toxaphene was assessed for 11 freshwater fish species in irrigation channels, agricultural return flow drains, a drain collecting lagoon and sections of the Colorado River at the Mexicali valley in Baja California, México, during August 2015-April 2016. Arsenic (2.90 ng ml-1) and Se (1.41 ng ml-1) in water had the highest concentrations in the return flow drains (Hardy River and Xochimilco Lagoon, respectively). However, fish axial muscle tissue had the highest concentration of Se (8.3 µg g-1) and Hg (0.36 µg g-1) in Colorado River fresh water, while As (1.7 µg g-1) in Hardy River fish was highest. Selenium concentrations in all fishes and toxaphene in Cyprinus carpio and Ameiurus natalis are above the safe levels for human consumption (0.3 µg g-1 and 180 ng g-1 respectively). Toxaphene was detected in the fish axial tissue, having the highest concentrations in Poecilia latipinna (690 ng g-1) in the Colorado River. The low proportion of the 8-Cl toxaphene congeners in fish suggests degradation of this pollutant. Tilapia. sp. cf. zillii had the most genotoxic damage with 7.4 micronucleated erythrocytes per 10,000 erythrocytes in Xochimilco Lagoon and 2 in Hardy River. The genotoxicity in all the fish species studied was significantly correlated to the concentrations of As and Se in water.

Anabolic androgenic steroids induce micronuclei in buccal mucosa cells of bodybuilders.

OBJECTIVE: To evaluate genotoxicity of anabolic androgenic steroids (AAS) in male bodybuilders by a micronucleus assay in buccal mucosa cells. METHODS: 11 male bodybuilders volunteered to participate in this study and two groups were formed: group 1 (n = 6), without AAS consumption and group 2 (n = 5), with AAS consumption. A sample of buccal epithelium was taken from each participant once a week for 6 weeks. Samples were fixed, stained and analysed by a light microscope, and 2000 cells were counted from each slide. Results are expressed as micronucleated cells (MNC) per 1000 cells and were analysed by the Mann-Whitney U test and Wilcoxon's test. RESULTS: A marked increased in MNC was seen in bodybuilders with AAS consumption compared with those without AAS consumption (mean (SD) 4.1 (2.4) MNC/1000 cells vs 0.4 (0.4) MNC/1000 cells, respectively; p<0.004). Intragroup comparisons showed no differences in the MNC frequencies during the sampling time in group 1, whereas the MNC frequency in group 2 varied significantly, reaching the highest MNC frequencies in the third and fourth week of sampling (5.9 (2.4) MNC/1000 cells; 5.8 (1.8) MNC/1000 cells, respectively); frequency in the first sampled week was 1.1 (0.1) MNC/1000 cells. Significant differences in all sampled weeks were found between the two groups. CONCLUSION: AAS consumption increased the frequency of MNC from buccal mucosa in bodybuilders.

Variation of micronucleated erythrocytes in peripheral blood of Sciurus aureogaster in relation to age: an increment of micronucleated polychromatic erythrocytes after the administration of colchicine.

In some species, in which the human is included, the influence of age in the variation in the number of micronucleated erythrocytes (MNE) is known. In the present work we show how the process of aging influences the number of spontaneous MNE in the gray squirrel (Sciurus aureogaster). Because of the difficulty of knowing the age of each animal, 69 animals were weighed at their arrival to the laboratory and at the start of sample taking, with the supposition that the heaviest animals were the oldest and those with the lightest weight were the youngest. The major number of MNE was found in the younger animals, whereas the adults displayed less MNE (P < 0.0001). A group of 11 animals were sampled every 15 days over a period of 6 months, and the number of MNE were found to decrease with an increment in the weight in conformity with the time elapsed. These results showed that in the gray squirrel, the number of spontaneous MNE in peripheral blood depend on age. An additional interesting datum about the increment of MNE after the administration of colchicine is shown.

Genotoxicity assessment using micronuclei assay in rheumatoid arthritis patients.

OBJECTIVES: This study investigated whether: (i) rheumatoid arthritis (RA) patients have more micronuclei (MN) than healthy controls; (ii) methotrexate (MTX) treated RA patients have more MN than those not using MTX, and (iii) folic acid supplementation decreases the number of MN in MTX treated patients. METHODS: MN assays were performed in oral mucosa sweeps of 50 consecutive MTX treated RA patients, 30 consecutive RA patients not receiving MTX and 39 healthy controls. MTX treated RA patients were then randomly placed in a cross-over design to receive folic acid supplementation, and MN assays were repeated after 6 weeks. RESULTS: The MTX-RA patients had a mean age of 46 +/- 10 yrs and a mean disease duration of 12 +/- 9 yrs; 80% were women. The MTX dose range was 8.7 +/- 1.5 mg/week and the mean duration of use was 16 +/- 18 months. In the non-MTX RA group, the mean age was 48 +/- 14 yrs, the mean disease duration was 13 +/- 9 yrs, and 87% were women. At baseline, the number of MN were significantly higher in RA patients as compared with controls (3.31 +/- 2.3 vs 0.8 +/- 0.8, p <0.001). No difference in MN numbers was observed between users and non-users of MTX. Folic acid supplementation did not decrease the MN number in the MTX treated RA patients. CONCLUSIONS: Genotoxicity, as assessed by the MN assay, is increased in RA patients. These results suggest that genotoxicity is associated with RA itself and not with MTX use. Folic acid supplementation had no effect on the number of MN.

Micronucleated erythrocytes in splenectomized patients with and without chemotherapy.

The purpose of the present study was to investigate the range of micronucleated erythrocytes (MNE) in peripheral blood from splenectomized patients with and without genotoxic chemotherapy. The erythrocytes were stained with Wright and Giemsa for microscopic observation. To estimate the number of MNE, two series of 10000 erythrocytes per sample were analyzed and averaged. The results expressed as mean +/- standard deviation were as follows: control patients with genotoxic chemotherapy (n = 6) 2.5 +/- 1.5 (range 1 to 5 MNE); splenectomized patients with genotoxic chemotherapy (n = 7) 65.2 +/- 17.7 (range: 47-108) MNE and splenectomized patients without genotoxic chemotherapy (n = 13) 29.5 +/- 5.8 MNE; (range: 18.5-35.6). The MNE number in the patients treated with genotoxic chemotherapy depended on the type of drugs utilized: cyclophosphamide, mitoxantrone, vincristine, busulphan, cytosine arabinoside and hydroxyurea. Upon these results, it is suggested that splenectomized people could be useful in monitoring exposures, and the baseline MNE level would serve as each person's pre-exposure control when either chronic or acute exposure to environmental mutagens is investigated.

Determination of diesel genotoxicity in firebreathers by micronuclei and nuclear abnormalities in buccal mucosa.

Diesel or its derivatives could have aneuploidogenic and/or clastogenic activity. Hence, the genotoxicity of diesel gases has been studied, considering exposure to them as potentially carcinogenic. The results obtained by different authors suggest the need to know the effects of direct and chronic exposure to diesel in humans, as in the case of the street workers called 'firebreathers' who fill their buccal cavity with diesel and then spread it to a burning torch many times during the day in order to give a 'dragon show' for 5 h a day and 6 days a week. The buccal samples of eight firebreathers were collected, processed and scored according to the criterion established by Tolbert et al., 1992 and then compared with positive and negative control groups. The results revealed that diesel was not micronucleogenic although it induces some nuclear abnormalities.

Evaluation of cisplatin + 5-FU, carboplatin + 5-FU, and ifosfamide + epirubicine regimens using the micronuclei test and nuclear abnormalities in the buccal mucosa.

In the present work, the micronuclei (MN) test was performed in buccal mucosal samples from patients with cancer, with (pre- and post-treatment) and without genotoxic chemotherapy (GC), identified micronucleated cells (MNC) and nuclear abnormalities (binucleated cells (BN), pycnosis (PN), "broken-egg" (BE), condensed chromatin (CC), karyorrhexis (KR), and karyolysis (KL). The objective was to evaluate the genotoxicity of cisplatin + 5-Fluorouracil (5-FU), carboplatin (CBP) + 5-Fluorouracil, and ifosfamide (IFO) + epirubicine (EPI) regimens. The ifosfamide + epirubicine regimen described here produced a micronucleogenic effect, whereas the regimens using platinum compounds were cytotoxic for buccal mucosal cells, which probably explain the absence of increase of micronucleated cells in these samples compared with basal levels. In patients with cancer (with and without genotoxic chemotherapy), the numbers of MNC, PN, KR, total nuclear abnormalities and KL increased, together with a decrease in BN cells and CC. On the other hand, as consequence of the cytotoxicity of the drugs, the number of binucleated cells decreased and the number of karyolytic cells increased. These results could be used as a cytotoxicity marker in the future studies for different drugs.

Induction of micronuclei in the domestic cat (Felis domesticus) peripheral blood by colchicine and cytosine-arabinoside.

One advantage of bioassays over other kinds of tests is the processing or metabolism of the compound by the organism. In a previous work, in which we reported the number of micronucleated erythrocytes (MNE) in the peripheral blood of 35 species, the cat was one of the species with the highest number of micronuclei (MN). Cats have a low level of circulating polychromatic erythrocytes (PCE), i.e. 0.05%, which is much lower than in the laboratory mouse, but higher than in species such as cows, donkeys, sheep, goats and horses. Thus, MN were scored in total blood erythrocytes. In the present work, we assess the cat as a test system for MN induction. Three doses of a colchicine-cytosine arabinoside mixture were administered to young cats during 4 days; then, the numbers of MNE in blood collected before the first injection and 48 and 96 h later were compared. The number of MNE increased with time, reaching the highest values in the samples taken 96 h after the administration of the micronucleogenic agents.

Spontaneous micronuclei in peripheral blood erythrocytes from 35 mammalian species.

In this paper we report the results of a study to determine the frequencies of spontaneous micronucleated erythrocytes (MNE) in peripheral blood of 35 mammalian species. The main goal was to find mammals with a high spontaneous frequency of MNE that could, therefore, be good candidates for biomonitoring genotoxic agents in their natural habitat. We obtained 187 peripheral blood samples, but in 13 of the species we could only sample one individual. A wide range in the number of MNE (1/434 to 0/40,000 erythrocytes) was observed. Since the number of individuals per species is not high enough, this results should be cautiously considered. The cat, mouse, giraffe, pig, opossum and capuchin monkey seem to be suitable species for biomonitoring for genotoxic events.

Evaluation of cisplatin + 5-FU, carboplatin + 5-FU, and ifosfamide + epirubicine regimens using the micronuclei test and nuclear abnormalities in the buccal mucosa.

In the present work, the micronuclei (MN) test was performed in buccal mucosal samples from patients with cancer, with (pre- and post-treatment) and without genotoxic chemotherapy (GC), identified micronucleated cells (MNC) and nuclear abnormalities (binucleated cells (BN), pycnosis (PN), "broken-egg" (BE), condensed chromatin (CC), karyorrhexis (KR), and karyolysis (KL)). The objective was to evaluate the genotoxicity of cisplatin+5-Fluorouracil (5-FU), carboplatin (CBP)+5-Fluorouracil, and ifosfamide (IFO)+epirubicine (EPI) regimens. The ifosfamide+epirubicine regimen described here produced a micronucleogenic effect, whereas the regimens using platinum compounds were cytotoxic for buccal mucosal cells, which probably explains the absence of increase of micronucleated cells in these samples compared with basal levels. In patients with cancer (with and without genotoxic chemotherapy), the numbers of micronucleated cells, pycnosis and karyolysis increased, together with a decrease in binucleated cells and chromatin-condensed. On the other hand, as consequence of the cytotoxicity of the drugs, the number of binucleated cells decreased and the number of karyolytic cells increased. These results could be used as a cytotoxicity marker in future studies for different drugs.

Spontaneous micronuclei in peripheral blood erythrocytes from 54 animal species (mammals, reptiles and birds): part two.

The normal numbers of micronucleated erythrocytes (MNE) observed in peripheral blood samples differ among species. This depends on the effectiveness of the spleen (or the rest of the reticuloendothelial system) to withdraw them from circulation. In our previous report, we assessed the number of MNE in the peripheral blood of 35 mammalian species. Here we show the results observed in 54 species including mammals, reptiles and birds. We obtained 212 peripheral blood samples from different species. In 14 species, only one individual was studied. Slides were stained with acridine orange. The total number of MNE (normo and polychromatic) in 10,000 erythrocytes per animal are shown. The species that display the higher MNE were: ocelote, lynx, owl, gray squirrel, hedgehog, lion, orange fronted parakeet and common barn owl. For this reason, these species could be tested as monitors for genotoxic events. Another interesting observation was that in the gray squirrel, we found the highest values of MNE in the smaller (younger) animals when compared with the larger (older) of the same species.

Differences in the number of micronucleated erythrocytes among young and adult animals including humans. Spontaneous micronuclei in 43 species.

In our previous report we speculated about the possibility that some species had high levels of spontaneous micronucleated erythrocytes (MNE) just in a juvenile stage, this is, that the MNE diminish as the reticuloendothelial system matures. Here we show this effect in species including rat, rabbit, pig, dog, cat, gray squirrel, lion, giraffe, white-tailed deer, opossum and even human. The number of spontaneous MNE that we found in 43 species is shown, and the proportions of polychromatic and normochromatic. This is our third report on spontaneous MNE in different species. We obtained 189 peripheral blood samples of mammals, birds and reptiles. From 12 species we obtained only one sample, and 16 were reported previously, but now the size of the sample has been increased. The species with the highest spontaneous MNE were the Vietnamese potbelly pig (with the highest MNE number), Bengal tiger, capuchin monkey, puma, ferret, owl, hedgehog, squirrel monkey, pig and white-tailed deer. These species could be used as monitors for genotoxic events.

Evaluation of genotoxic activity of maleic hydrazide, ethyl methane sulfonate, and N-nitroso diethylamine in Tradescantia.

OBJECTIVE: To assess the genotoxic activity of N-nitroso diethylamine (NDEA), maleic hydrazide (MH), and ethyl methane sulfonate (EMS) using two systems: the comet assay on nuclei from Tradescantia, and the pink mutation test on Tradescantia staminal hairs (clone 4430). MATERIAL AND METHODS: Tradescantia cups was obtained from Laboratorio de Citogenética y Mutagénesis del Centro de Ciencias de la Atmósfera de la Universidad Nacional Autónoma de México and treated with: N-nitroso diethylamine (NDEA) at 1, 5, 10 mM, maleic hydrazide (MH) at 1, 5, 10 mM and ethyl methane sulfonate (EMS) at 15, 30 and 45 mM; and used in both pink mutation assay and comet assay using cellular nuclei from Tradescantia staminal hairs. The observation of staminal hair was realized along eight days (6-14) after treatment), flowers produced day 14 after treatment were utilized done according to Underbrink. In previous reports on plants, were comet assay was used, breaking cellular wall and separating by centrifugation gradient are necessary. Here, nuclei from staminal hairs were obtained by squashing the cells (is not necessary to utilize to break special procedure cellular wall), collected using a nylon mesh of 80 Mm and next the comet assay was applied. Student's T test was the statistical test used for analyzing the comet assay data. RESULTS: Both assays showed a great sensitivity to the studied mutagens. A relationship between the dose-pink event and the dose-tail length was evident. Even though the Tradescantia mutation assay is a sensitive test with MH and EMS, low doses of NDEA were not able to induce a significant increase in the pink event frequencies; however, the comet assay was able to detect the mutagenic effect of NDEA at the same dose. Thus, it is clear that the comet assay is highly sensitive to the lowest dose of chemical mutagens. CONCLUSIONS: The comet assay on nuclei from Tradescantia staminal hairs is a useful tool to monitor genotoxic agents; it is simple, highly sensitive, and faster than the pink mutation test.