Cytogenotoxicity of rice crop water after application of the tricyclazole fungicide

ABSTRACT Tricyclazole is currently one of the fungicides recommended for the treatment of diseases in irrigated rice. However, there is relatively little information on its cytotoxic and genotoxic potential. The objective of this study was to evaluate the cytotoxicity and genotoxicity of rice crop water after apllication of the tricyclazole fungicide through the Allium cepa L. test. The rice crop water samplings were collected before and 1, 15 and 30 days after application of the fungicide in rice plant shoots. The Allium cepa roots were placed in contact with the rice crop water to check for possible chromosomal abnormalities and mitotic index of the bioindicators meristematic cells. The data obtained by the Allium cepa test indicates that the application of the tricyclazole fungicide leads to an increase in the genotoxic activity in the rice crop water, through the appearance of chromosomal abnormalities, without, however, causing significant effects on the mitotic index. The major chromosomal alterations observed were anaphasic and telophasic bridges and laggard chromosomes.

Avaliação de aberrações cromossômicas em trabalhadores de postos de gasolina da Zona Oeste do Rio de Janeiro / Avaliação de aberrações cromossômicas em trabalhadores de postos de gasolina da Zona Oeste do Rio de Janeiro

No âmbito da saúde ocupacional, as exposições a agentes químicos recebem cada vez mais atenção. Pela análise de bioindicadores, se faz possível identificar e quantificar substâncias nocivas à saúde e seus efeitos. Trabalhadores de postos de revenda de combustíveis veiculares (PRCV) estão expostos a uma mistura de hidrocarbonetos policíclicos aromáticos (HPAs) proveniente da gasolina, e nesta mistura encontra-se o benzeno, composto hematotóxico e carcinogênico, sem níveis seguros no ambiente, fato que corrobora para a importância de ações em vigilância ocupacional nesta área. O presente estudo avaliou os efeitos genotóxicos, através do teste de Aberrações cromossômicas (ACs), de uma exposição ocupacional aos vapores de gasolina em frentistas da Zona Oeste do Rio de Janeiro. O projeto central foi aprovado pelo Comitê de Ética em Pesquisa da Ensp/Fiocruz (CAAE17438013.5.0000.5240, parecer 434.418). 39 trabalhadores de seis PRCV da área programática 5.3 (bairros de Santa Cruz, Paciência e Sepetiba) responderam a dois questionários sobre fatores socioeconômicos, processo de trabalho e histórico de saúde; amostras de sangue e urina foram coletadas para determinação de hemograma, análises bioquímicas, ACs e ácido trans, trans-mucônico urinário (ATTM). Os voluntários não apresentaram histórico de doenças de possível associação com a exposição, assim os resultados de hemograma e bioquímica, em valores médios, ficaram dentro das faixas de normalidade. Os processos de trabalho e hábitos dos trabalhadores foram avaliados e não apresentaram relação com as ACs. (...) Os resultados sugerem que o teste de ACs não deve ser utilizado de forma isolada para avaliar exposições a baixas doses de benzeno por sua inespecificidade, mas ainda representa uma ferramenta útil na avaliação de dano precoce à saúde humana...

On the Occupational Health field, exposure to chemical agents is getting more attention, since technologies’ advances allow identification of health early effects caused by such exposures. By the use of bioindicator’s analysis, it is possible to identify and quantify harmful substances and their effects. Gas station workers are exposed to a hidrocarbon’s mixture from gasoline, in which can be found benzene, carcinogenic and hematotoxic substance, with no safe levels on environment, reinforcing the need of occupational vigilance actions. This study evaluated the genotoxic effecs, using the chromosomal aberration’s test (CAs), of an occupational exposure to gasoline fumes in gas station workers from Rio de Janeiro’s West Side. The main project was approved by Ensp/Fiocruz Research’s Ethics Committee (CAAE 17438013.5.0000.5240, case 434.418). Thirty-nine workers from six gas stations from the districts of Santa Cruz, Paciência and Sepetiba answered questionnaires concerning socio-demographic, work and health questions; blood and urine samples were taken to assess CBC, biochemical factors, trans, trans-muconic acid (TTMA) and chromosomal aberrations. The subjects did not report history of diseases that could be related to the exposure, so the results of CBC and biochemical factors were at normality ranges. Work processes and the subjects’habits were assessed and were not associated to CAs. TTMA measurement and statistical evaluation through ANOVA showed a correlation between this metabolite and smoking habit (...), and the high concentration gets along with literature. (...) The results suggest chromosomal aberrations test shall not be used as the only mechanism to evaluate benzene exposure at lower doses for its inespecificity, but the test is, for it self, a useful feature for early human health damage evaluation...

Response of the G2-prophase checkpoint to genotoxic drugs in lymphocytes from healthy individuals

We analyzed the in vitro effects of the anti-tumoral drugs doxorubicin, cytosine arabinoside and hydroxyurea on the G2-prophase checkpoint in lymphocytes from healthy individuals. At biologically equivalent concentrations, the induced DNA damage activated the corresponding checkpoint. Thus: i) there was a concentration-dependent delay of G2 time and an increase of both the total DNA lesions produced and repaired before metaphase and; ii) G2-checkpoint adaptation took place as chromosome aberrations (CAs) started to appear in the metaphase, indicating the presence of unrepaired double-strand breaks (DSBs) in the previous G2. The checkpoint ATM/ATR kinases are involved in DSB repair, since the recorded frequency of CAs increased when both kinases were caffeine-abrogated. In genotoxic-treated cells about three-fold higher repair activity was observed in relation to the endogenous background level of DNA lesions. The maximum rate of DNA repaired was 3.4 CAs/100 metaphases/hour, this rise being accompanied by a modest 1.3 fold lengthening of late G2 prophase timing. Because of mitotic chromosome condensation, no DSBs repair can take place until the G1 phase of the next cell cycle, when it occurs by DNA non-homologous end joining (NHEJ). Chromosomal rearrangements formed as a consequence of these error-prone DSB repairs ensure the development of genome instability through the DNA-fusion-bridge cycle. Hence, adaptation of the G2 checkpoint supports the appearance of secondary neoplasia in patients pretreated with genotoxic drugs.

Comparación en la frecuencia espontánea e inducida de aberraciones cromosómicas en médula ósea de ratones OF-1 y C57BL/6/cenp / Comparison between induced and spontaneous chromosomal aberrations in OF-1 and C57BL/6/cenp bone marrow mice

El ensayo citogenético in vivo es un ensayo de mutagenicidad a corto plazo de gran sensibilidad, útil para detectar fundamentalmente aberraciones cromosómicas estructurales in vivo. El objetivo del trabajo consistió en determinar el biomodelo experimental más eficiente en este ensayo mediante la comparación de la frecuencia espontánea e inducida de aberraciones cromosómicas en células de la médula ósea, en uno y otro sexos de 2 líneas de ratones (OF-1 y C-57BL/6/cenp). Se formaron 4 grupos experimentales, uno control negativo, dos tratados durante 14 días con sustancias vehículos por vía oral, NaCl (0,9 por ciento) y tween 65 (2 por ciento), y uno control positivo tratado a las 48 y 24 h antes del sacrificio con ciclofosfamida (50 mg/kg) por vía intraperitoneal. La línea de ratones OF-1 resultó tener una frecuencia espontánea más baja en las variables analizadas que la C-57BL/6/cenp, obteniéndose un menor número espontáneo de células totales con aberraciones y mayor sensibilidad a la ciclofosfamida que la línea C-57BL/6/cenp. Se concluye que los ratones OF-1 y C-57BL/6/cenp, constituyen buenos modelos a emplear en los estudios genotoxicológicos, dada la baja frecuencia espontánea de aberraciones cromosómicas estructurales y numéricas analizadas aunque se recomienda el uso de la línea OF-1

The in vivo cytogenetics array is a very sensible short term mutagenesis method useful to detect mainly the in vivo the structural chromosomal aberrations. The aim of present paper was to determine the more effective experimental bio-model in this type of model to compare the spontaneous and induced frequency of the above mentioned aberrations in bone marrow cells in both sexes of two mice species (OF-1 and C-57BL/6/cenp). Four experimental groups were designed, one of negative control, twotreated during 14 days using oral vehicle substancesm NaCI (0.9 percent) and tween 65 (2 percent) and one of positive control treated at 48 and 24 h before sacrifice using cyclophosphamide (50 mg/kg) by intraperitoneal route. The OF-1 mice species had the lowest spontaneous frequency in variables analyzed that the C-57BL6/cenp species, achieving a lower spontaneous number of total cells with aberrations and a great sensitivity to cyclophosphamide than the C-57BL/6/cenp species. We conclude that the OF-1 and C-57BL/6/cenp mices were good models to be used in genotoxicological studies due to the low spontaneous frequency of the above mentioned aberrations and the numerical ones analyzed, thus it is recommended the use of OF-1 species

Ability of Allium cepa L. root tips and Tradescantia pallida var. purpurea in N-nitrosodiethylamine genotoxicity and mutagenicity evaluation

N-nitroso compounds, such as N-nitrosodiethylamine (NDEA), can be formed by the reaction of secundary amines with nitrosating agents, and are suspected to be involved in tumors in humans. NDEA has been considered a weak carcinogen in genotoxic assays probably due to the inefficient nitrosamine activation system that is used and/or to the efficient repair system. In this work, we evaluated the sensibility of Allium cepa L. root tips and Tradescantia stamen hair mutation assay (Trad-SH) using Tradescantia pallida var. purpurea for NDEA (0.1; 0.5; 5 and 25mM) genotoxicity and mutagenicity induction. Allium cepa L. was treated with different NDEA concentrations for 3h, for 3 consecutive days, including negative control (distilled water) and positive control maleic hydrazide (MH 30mg/mL). After treatment, the roots were hydrolyzed, squashed, and the mitotic index (MI) and cytological abnormalities were scored. The results revealed a cytostatic effect of NDEA (0.5 and 5mM), showing a significant reduction in the MI. Chromosome stickiness suggests a NDEA toxic effect. T. pallida purpurea did not respond to mutagens with a dose-dependent pattern. In conclusion, our study indicates that the root tips of Allium cepa L. have sensibility to detect NDEA genotoxicity, but not for Trad-SH test.

Nitrocompostos, como N-nitrosodietilamina (NDEA), podem ser formados pela reação entre uma amina secundária e agentes nitrosantes e são suspeitos de estarem envolvidos na formação de tumores em humanos. NDEA é considerada um carcinógeno fraco e ensaios genotóxicos provavelente pela utilização de um sistema de ativação ineficiente e/ou pela utilização de um eficiente sistema de reparo. Neste trabalho, nós avaliamos a sensibilidade de ensaios com Alliu cepa L. e Tradescantia pallida var. purpurea (Trad-SH) à genotoxicidade e mutagenicidade induzidas por diferentes concentrações de NDEA (0,1; 0,5; 5 e 25mM) por 3h, por 3 dias consecutivos, incluindo controle negativo (água destilada) e controle positivo, hidrazida maleica (MH 30mg/mL). Depois do tratamento, as raízes foram hidrolizadas, esmagadas e o índice mitótico (IM) e anormalidades citológicas foram contadas. Os resultados revelaram um efeito citostático de NDEA (0,5 e 5mM), pela significante redução do IM. Chromosome stickiness sugere um efeito citotóxico de NDEA. T pallida purpurea não respondeu ao mutágeno com um padrão dose dependente. Em conclusão, nossos estudos indicaram que raízes de Allium cepa L. possue sensibilidade na detecção genotóxica de NDEA, mas não para o ensaio Trad-SH.

Cytogenotoxicity of Cymbopogon citratus (DC) Stapf (lemon grass) aqueous extracts in vegetal test systems

The lemon grass, Cymbopogon citratus (DC) Stapf, is an important species of Poaceae family commonly used in the folk medicine in many countries. The aim of this study was to investigate the cytotoxic and genotoxic effects of aqueous extracts from C. citratus leaves on Lactuca sativa (lettuce) root tip meristem cells by cytogenetic studies that have never been done before for lemon grass extracts. For this, lettuce seeds were treated for 72h with different concentrations of lemon grass aqueous extracts (5; 10; 20 and 30 mg/mL). The percentage of germination, root development and cellular behavior were analyzed, and the results showed that the highest concentration of aqueous extracts reduced the mitotic index, the seed germination and the root development of lettuce. The extracts have also induced chromosome aberrations and cellular death in the roots cells of L. sativa.

O capim-limão, Cymbopogon citratus (DC) Stapf, é uma importante espécie da família Poaceae com uma comum utilização na medicina popular em vários países. O objetivo deste estudo foi investigar os efeitos citotóxicos e genotóxicos do extrato aquoso das folhas de C. citratus em células meristemáticas de Lactuca sativa (alface) por meio de estudos citogenéticos, uma vez que estudos desta natureza não existem para extratos aquosos de capim-limão. Para isso, sementes de alface foram tratadas por 72h com diferentes concentrações de extratos aquosos feitos das folhas de capim-limão (5, 10, 20 e 30 mg/mL). O percentual de germinação, desenvolvimento radicular e o comportamento celular foram avaliados e os resultados mostraram que as concentrações mais elevadas dos extratos aquosos reduziram o índice mitótico, o percentual de germinação das sementes e desenvolvimento radicular da alface. Os extratos também induziram aberrações cromossômicas e morte celular nas células das raízes de L. sativa.

Cytogenetic study of myelodysplastic syndrome from India.

Background & objectives: Myelodysplastic syndrome (MDS) represents a group of clonal haematological disorders characterized by progressive cytopenia reflecting defects in erythroid, myeloid and megakaryocytic maturation. The incidence of MDS is more in older age groups and frequent chromosome abnormalities reported to be monosomies 5 and 7. However, the data on cytogenetic changes in Indian MDS patients are scanty. The present study was therefore undertaken to study the aetiology and frequency of chromosomal changes in MDS patients, attending a tertiary care hospital in Maharashtra, India. Methods: The study was carried out in 145 MDS patients for six years (2001-2006) at National Institute of Immunohaematology (ICMR), and KEM Hospital, Mumbai, India. The patients were diagnosed according to FAB and WHO classification. Cytogenetic study was carried out using GTG-banding and fluorescence in situ hybridization (FISH) methods. Statistical analysis was done with c2 and Fisher’s exact test. Results: Chromosomal abnormalities, including novel chromosome aberrations were detected in 54.48 per cent MDS patients and frequency of chromosomal aberrations increased with increase in age (>30 yr). Among occupational exposure factors, chromosomal aberrations significantly (P<0.05) associated with pesticides exposure. Interpretation & conclusion: Our findings showed 54.48 per cent chromosome abnormalities including novel chromosome aberrations in MDS patients and these chromosome aberrations were increased with advancing age. In our series a high frequency of younger population (53%) developed MDS, a detailed molecular genetics and aetiological factors need to be studied.

Cytogenetic study of Ascaris trypsin inhibitor in cultured human lymphocytes with metabolic activation.

The trypsin inhibitor (ATI) isolated from gastrointestinal nematode Ascaris suum was tested in vitro for induction of chromosome aberrations and sister chromatid exchanges (SCE). Genotoxicity assessment of purified ATI was carried out on metaphase plates received from peripheral blood lymphocyte macroculture (48 h test of structural chromosome aberrations and 72 h test of SCE) with exogenous metabolic activation. ATI was tested in dose of 25, 50 and 100 mu g per ml of culture. Kinetics of cell divisions were determined by the replication index (RI). The mitotic index (MI) was expressed as a number of metaphases per 1000 nuclei analysed. Analysis of chromosome aberrations showed that higher doses of ATI (50 and 100 mu g-ml) significantly increased the frequency of chromosome aberrations (mainly of chromatid gaps and breaks) compared to the negative control. All concentrations of ATI caused a statistically significant reduction in the MI and RI. In comparison with the negative control, a significant increase in the SCE frequency was observed in all applied doses of ATI. Thus, in the presence of S9 activation, the Ascaris trypsin inhibitor showed potential clastogenic activity and inhibition of the dynamics of lymphocyte divisions.

Protective effect of liposomal formulation of tuftsin (a naturally occurring tetrapeptide) against cyclophosphamide-induced genotoxicity and oxidative stress in mice.

Tuftsin, a naturally occurring tetrapeptide with a sequence Thr-Lys-Pro-Arg was evaluated for its in vivo protective effect against cyclophosphamide-induced genotoxicity and oxidative stress in Swiss albino mice. The anticancer drug cyclophosphamide (CP) was administered intra-peritonially to induce mutagenic effect. The drug treatment caused significant increase in chromosomal aberrations, formation of micronucleated polychromatic erythrocytes (MNPCE's), as well as oxidative stress and decrease in lipid peroxidation in liver of the animals. The pretreatment with tuftsin abolished such effects in dose-dependent manner and also increased mitotic index in the experimental animals. Results of the present study validated chemo-preventive properties of tuftsin against CP-induced chromosomal mutations and cellular injury of liver by oxidative stress.

Possible modulating action of plant infusion of Ocimum sanctum L. on chromosomal aberrations and sister chromatid exchanges induced by chlormadinone acetate in human lymphocytes in vitro.

Chlormadinone acetate (CMA) is a synthetic progesterone analogue. It has its usage in oral contraceptives formulations and also for estrous synchronization of animals. The aim of the present study is to study the anti- genotoxic activity of the plant infusion against the CMA induced genotoxic damage on cultured human lymphocytes, using chromosomal aberrations and sister chromatid exchanges (SCFs) as parameters. For chromosomal aberration analysis, the treatment of 40 microM of CMA was associated with 4.33% abnormal metaphases. The treatment of 40 microM of CMA, separately with 1.075 x 10(-4), 2.125 x 10(-4) and 3.15 x 10(-4) gm l(-1) of plant infusion results in the reduction of the number of abnormal metaphases i.e. 2.67%, 2.00% and 1.67% respectively. For sister chromatid exchange analysis, the frequency of sister chromatid exchange per cell (SCE(S)/Cell) for the treatment of 40 microM of CMA was 6.43. The treatment of 40 microM of CMA, separately with 1.075 x 10(-4), 2.125 x 10(-4) and 3.15 x 10(-4) gm l(-1) of plant infusion results in the significant reduction of the frequency of SCE(S)/Cell i.e. 3.76, 3.01 and 2.94, respectively, as compared to the CMA (40 microM) treatment alone (6.43). The used dosages of plant infusion did not increase chromosomal aberrations and sister chromatid exchanges at significant level as compared to the untreated. The results of the present study suggest that the plant infusion per se does not have genotoxic potential, but can modulate the genotoxicity of chlormadinone acetate in human lymphocytes in vitro.

Genotoxic effects among petrol station workers

Benzene has been internationally recognized as a potent toxin, particularly for its effects on the blood forming system of the bone marrow and its association to a large number of haematological disorders. This study aimed to assess the cytogenetic damages related to occupational exposure to benzene by calculating the mitotic index [MI], nuclear division cytotoxicity index [NDCI], binucleated cells ratio and chromosomal aberrations. Peripheral blood samples were collected from 30 benzene exposed workers and 10 from unexposed- controls- persons. 20 out of the exposed workers were occupationally exposed to benzene from 2 to more than 4 years. The rest of workers were exposed to benzene from one month to one year. The mean MI in the benzene exposed workers [5.72 +/- 0.62] was found significantly higher than in controls [4.03 +/- 0.37]. The highest MI mean was calculated in the exposure group 4 to above years. The NDCI of the exposure workers [3.38 +/- 0.54] was also significantly higher than in control [2.04 +/- 0.76]. Lower NDCI mean was calculated in the 4 to above years exposure. Chromosomal aberrations were observed in the exposed group. Polyploidy, aneuploidy [5 monosomy and 9 trisomy] and structural aberration [del 8q] were detected in the exposed groups 0-3 years. MN frequencies were significantly increased in relation with length of employment. According to the MN results and the chromosomal aberrations detected in the exposed groups, it could be possible that a correlation found between the elevated values of the MN and the detected chromosomal aberrations

In vitro cytogenetic studies of cypermethrin on human lymphocytes.

Assessment of cytotoxicity and response to external factors like pesticides were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide (MTT) or MTT assay, which measures mitochondrial metabolism in the entire cell culture and provides information about the percentage of cell survival. Utilizing the MTT assay, the cytotoxicity of cypermethrin was determined on lymphocyte cultures from human peripheral blood samples, the short-term lymphocyte cultures were incubated with various aliquots of the cypermethrin and the LC50 was found to be 33.6 microM. Lymphocytes treated with low-doses (1/10 of LC50) of cypermethrin showed an increase in the frequency of chromosomal aberrations and found to be significant. Karyotype analysis revealed more satellite associations and chromosomal breaks in cypermethrin treated samples. Low-doses of the pesticide also induced single-strand breaks in the DNA as assessed by comet assay. The pesticide caused increase in the comet tail length with increase in pesticide concentration, implicating genotoxicity in somatic cells. It is concluded that In vitro assays could give important information of the mechanism of toxicity at low dosages and impact on genetic material of human origin.

Evaluation of mercury toxicity by some cytological indices in leucocyte cultures.

The genotoxicity induced by different levels of inorganic mercury was evaluated by chromosome metaphase analysis in human leucocytes, treated in vitro for 72 hr. Mitotic index gradually decreased with an increase in concentration of mercury but the reverse phenomenon was observed with respect to chromosomal aberration due to its probable interaction with protein and DNA.

Antigenotoxic effect of allicin against methyl methanesulphonate induced genotoxic damage.

Allicin, one of the sulfur compounds especially thiosulphonates of garlic (Allium sativum), possesses antioxidant and thioldisulphide exchange activity and is also shown to cause a variety of actions potentially useful for human health. In this investigation we determined its antigenotoxic potential using chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs) induced by methyl methanesulphonate (MMS) as genotoxic end points both in the presence as well as absence of rat liver microsomal activation system (S9 mix) in cultured human lymphocytes. We tested the effect of 5, 10 and 20 microM of allicin on the damage exerted by 60 microM of MMS. The levels of CAs and SCEs were lowered suggesting an antigenotoxic role of allicin against genotoxic damage both in the presence as well as absence of metabolic activation.

Evaluation of genotoxic potential of norethynodrel in human lymphocytes in vitro.

The genotoxicity study of a synthetic progestin norethynodrel, was carried out on human lymphocytes chromosomes using sister chromatid exchanges (SCEs), replication index (RI) and chromosomal aberrations (CAs) as parameters. The study was carried out in the presence and absence of metabolic activation (S9 mix). Norethynodrel was studied at three different concentrations (20, 40 and 60 microg/ml of peripheral blood lymphocyte culture) and was found non-genotoxic in the absence of metabolic activation. But in the presence of S9 mix norethynodrel increased SCE (p<0.03) and CA (p<0.005) frequencies and inhibits lymphocyte proliferation (p<0.03) at 60 microg/ml. The results suggest a genotoxic and cytotoxic effect of norethynodrel in human lymphocytes in vitro in the presence of S9 mix.

Genotoxic effects of rotenone on cultured lymphocytes

Rotenone is a heterocyclic compound widely used as an insecticide, acaricide and piscicide. Its toxicity is mainly caused by the inhibition of mitochondrial respiratory processes and ATP production, resulting in the generation of reactive oxygen species. Reactive oxygen species can interact with DNA, RNA and proteins, leading to cell damage, followed by death. We used the Comet assay, and we analyzed chromosome aberrations, in order to evaluate the genotoxic and clastogenic effects of rotenone on the different phases of the cell cycle. Cultured human lymphocytes were treated with 1.0, 1.5 and 2.0 microg/mL rotenone during the G1, G1/S, S (pulses of 1 and 6 h), and G2 phases of the cell cycle. Rotenone induced DNA damage and was clastogenic, but the clastogenicity was detected only with treatments conducted during the G1/S and S phases of the cell cycle. Rotenone also induced endoreduplication and polyploidy in treatments made during G1, while it significantly reduced the mitotic index in all phases of the cell cycle.

Cytogenetic and genotoxic effects of the insecticides, imidacloprid and methamidophos

We examined the cytogenetic and genotoxic effects of the neonicotinoid insecticide imidacloprid and the organophosphate insecticide methamidophos, when administered alone or in combination. These insecticides were tested with the bone marrow chromosome aberration assay and micronucleus test in rats and by the bacterial mutation assay (Salmonella/microsome mutagenicity assay). Wistar albino rats were orally fed daily with laboratory chow treated with various concentrations of insecticides, 50 and 100 mg/kg imidacloprid, 2.5 and 5 mg/kg methamidophos, and 2.5 and 5 mg/kg imidacloprid plus methamidophos, respectively, for 90 days. Numerical and structural chromosomal aberrations were evaluated. Significant differences were detected between all the insecticide-administered groups versus the control group and between the two concentrations of the pesticide-treated groups. Both concentrations of the insecticides induced a dose-related increase in the micronucleus frequency (P < 0.05). Dose-related increases in the number of revertants were observed with the two Salmonella strains (TA98 and TA100). All tested doses of the insecticides demonstrated mutagenic activity in the presence of S9 mix. These results lead us to the conclusion that the synergistic effect of methamidophos and imidacloprid causes an increase in potential damage to non-target organisms.

Genotoxicity and toxicological effects of acrylamide on reproductive system in male rats

The toxicity of acrylamide was evaluated through mutagenicity of Salmonella, chromosome aberration of Chinese hamster lung fibroblasts, micronucleus formation in mice and reproductive toxicity in rats. Based on Ames test, acrylamide showed mutagenic potency for strains TA98 and TA100. Moreover, both chromosomal aberration assay and micronucleus assay indicated that acrylamide might have genotoxic potency; the chromosomal aberration frequencies were observed to be proportional to acrylamide concentrations of 5-50 mM, and acrylamide significantly increased micronuclei in peripheral blood cells of mice at doses of higher than 72.5 mg/kg. Male rats were treated with acrylamide at doses of 0, 5, 15, 30, 45, or 60 mg/kg/day for 5 consecutive days, and the toxicity of acrylamide was observed. In the group treated with the highest dose of acrylamide (60 mg/kg/day), the loss of body weight and reduced testis weight were observed. Also the epididymides weights were reduced significantly in all the groups treated with acrylamide. The number of sperms in cauda epididymidis decreased significantly in an acrylamide dose-dependent manner. Rats treated with 60 mg/kg/day of acrylamide showed several histopathological lesions in the seminiferous tubules. There were thickening and multiple layering of the tubular endothelium, and the formation of many multinucleated giant cells in seminiferous tubules. Taken together, acrylamide not only causes the genotoxicity of eukaryotic cells and mice but also shows the toxicological effects on reproductive system in male rats.

Estudios sobre genotoxicidad del ozono / Studies on ozone genotoxicity

Se hizo una revisión, dado que existen evidencias contradictorias sobre la genotoxicidad del ozono y se analizó la bibliografía existente sobre este tópico importante de la toxicología y las valoraciones al respecto. El ozono es una especie reactiva de oxígeno y un constituyente natural importante de la atmósfera, existen numerosas evidencias y el consenso de sus efectos tóxicos para el ser humano y los animales, especialmente por vía inhalatoria que afecta los bronquios y pulmones. Sin embargo, también muchas evidencias se han acumulado de que este gas cuando es utilizado por otras vías de administración puede ejercer efectos beneficiosos como tratamiento de enfermedades diversas, lo que ha dado apoyo al desarrollo de la ozonoterapia, sobre la que hoy se investiga en numerosos países y entre estos Cuba

Micronúcleos y otras anormalidades nucleares en el epitelio oral de mujeres expuestas ocupacionalmente a plaguicidas / Micronuclei and other nuclear abnormalities in the oral epithelium of female workers exposed to pesticides

In order to study if banana fields labour exposure to pesticides produces some kind of DNA damage, we determine the presence of micronuclei in epithelial oral cells in working women in Guapiles and Siquirres, Costa Rica, as an effect biomarker. We also analyzed other abnormalities in the nucleus of those cells such as broken-egg, karyolysis or kariorrhexis, to see if there was some kind of genotoxicity or citotoxicity. The women group exposed to pesticides worked in packing bananas plant from different independent farms. The control group of women had never done any farming tasks; they did not live in the banana fields, neither their husband. We got information about the life style, medical and familial history of the participants through an interview. We did not found any significant increment in the frequency of micronuclei form the exposed group compared with the controls. The other nuclei abnormalities showed signs of citotoxicity or genotoxicity in the controls, associated with the intake of coffee and dental x-rays. These results do not rule out at that pesticides used in packing bananas are agents capable of producing damage to the DNA, but it seems that micronuclei from the oral epithelium is not the most adequate marker to measure it.