Cytogenetic studies on the effect of feeding mice with stored wheat grains treated with malathion.

The cytogenetic effect of malathion residues in wheat grains stored for different periods of time (4, 12, 24 weeks) was evaluated in Swiss mice. The studies included: (1) chromosomal aberrations analysis in bone-marrow and spermatocyte cells; (2) chromosomal aberrations and sister chromatid exchange (SCE) analysis in spleen cell culture from mice fed with stored wheat grains. The tested doses were 8.36 (applied dose), 25.08 and 41.80 mg malathion kg(-1) wheat grains. The results demonstrated that the cytogenetic effect induced in different mouse tissues by malathion residues was dose-dependent and increased with increasing of both feeding and storage periods.Feeding mice with wheat grains stored for 4 weeks had a non-significant effect with respect to the induction of chromosomal aberrations or SCEs. Significant chromosome damage and increase of SCEs were observed in mice fed with wheat grains stored for 12 weeks. The maximum effect was recorded in mice fed for 12 weeks with the grains treated with the highest tested dose and stored for 24 weeks. However, mitomycin C i.p.-injected in mice at 1 mg kg(-1) body weight (b.w.) (positive control) induced a higher effect. The percentage of chromosome aberrations reached 13.60+/-0.98, 13.60+/-0.77 and 11.73+/-0.98 (P<0.01) in bone-marrow, cultured spleen cells and spermatocytes, respectively. The significant increase of abnormalities in spermatocytes was seen for univalent formation only, predominantly of the sex chromosomes. The frequency of SCEs was 10.76+/-0.62 per cell (P<0.01) in cultured spleen cells compared with 5.46+/-0.45 per cell for control and 14.66+/-0.54 per cell for the positive control.The obtained results indicate that malathion residues in stored wheat grains have potential genotoxic effect in mice under the conditions tested.     

Cytogenetic studies in mice treated with the jet fuels, Jet-A and JP-8

The genotoxic potential of the jet fuels, Jet-A and JP-8, were examined in mice treated on the skin with a single dose of 240 mg/mouse. Peripheral blood smears were prepared at the start of the experiment (t = 0), and at 24, 48 and 72 h following treatment with jet fuels. Femoral bone marrow smears were made when all animals were sacrificed at 72 h. In both tissues, the extent of genotoxicity was determined from the incidence of micronuclei (MN) in polychromatic erythrocytes. The frequency of MN in the peripheral blood of mice treated with Jet-A and JP-8 increased over time and reached statistical significance at 72 h, as compared with concurrent control animals. The incidence of MN was also higher in bone marrow cells of mice exposed to Jet-A and JP-8 as compared with controls. Thus, at the dose tested, a small but significant genotoxic effect of jet fuels was observed in the blood and bone marrow cells of mice treated on the skin.     

Cytogenetic effects of malathion insecticide on somatic and germ cells of mice

Male mice dermally exposed to single or multiple treatment (5 days/2 weeks) showed that the ability of malathion to induce chromosome aberrations in somatic (bone marrow) and germ cells (primary spermatocytes) was related to the type of treatment and dose used. Statistically significant increases of chromosome aberrations in bone marrow cells occurred after single treatment (500 and 2000 mg/kg body wt) when chromatid gaps were included and after multiple treatment (250 and 500 mg/kg) when they were excluded. No dose-response relationships were observed for either treatment. In germ cells, malathion induced a significant increase of univalents in both types of treatment but structural chromosome aberrations were induced only by multiple treatment. Malathion induced a significant decrease of the mitotic indices in the bone marrow.     

Cytogenetic studies in patients treated with penicillamine.

Cytogenetic studies were performed on bone-marrow cells from 11 patients with rheumatoid arthritis treated with penicillamine. One of the patients was studied while developing a granulocytopenia and thrombocytopenia. The findings show that penicillamine had no chromosome-damaging effect as estimated by the micronucleus test and by the number of structural chromosomal aberrations.     

Growth of wheat seedlings raised from the grains treated with 28-homobrassinolide

An experiment was conducted under controlled conditions, in which grains of wheat (Triticum aestivum L. cv. Raj-3077) were soaked in 0, 1, 3 and 5 μM aqueous solutions of 28-homobrassinolide (HBR) for 4, 8 and 12 hours. The seedlings raised from the grains pre-treated with HBR possessed significantly higher leaf number, fresh and dry weight·plant⁻¹, nitrate reductase (NR,E.C. 1.6.6.1) and carbonic anhydrase (CA, E.C. 4.2.1.1) activities on 25 and 35 days, after sowing. The soaking of the grains in 3 μM concentration for 8 or 12 hours produced the most vigorous seedlings.     

Cytogenetic effect of malathion in in vitro culture of human peripheral blood

Chromosomal aberrations, sister-chromatid exchanges and mitotic indices were observed in human peripheral leukocytes, treated with four different concentrations of malathion (0.02, 0.2, 2 and 20 μg/ml), an organophosphate pesticide, added to the culture medium at 0, 24 and 48 h after culture initiation. These cultures showed a dose-dependent increase in the frequency of chromosomal aberration as well as sister-chromatid exchanges. There was a significant decreases in mitotic index at all concentrations.     

Cytogenetic studies on wild house mice from Belgium

The present status of Robertsonian karyotype variation in populations of wild mice from Belgium is presented. Two fusions, Rb(4.12)1Nam and Rb(5.10)3Nam, were identified in the central plain of this flat country. Surrounding this region only mice with the usual 2n=40 karyotype occurred. From the distribution pattern some possible relationships to other Rb populations from Europe are discussed.     

Cytogenetic studies on the effect of chronic gamma irradiation onVicia faba

Vicia faba seeds (cv. Giza 1) were planted in the Inshas gamma radiation field where they were chronically irradiated during the whole life of the plant. The percentage of the induced abnormal P.M.Cs, as well as the frequency of abnormal P.M.Cs in the different meiotic stages were proportional with the given doses. The main types of chromosome aberrations were anaphase and telophase bridges, fragmentation and lagging chromosomes. The nearest plants to the source showed an inhibition of shoot growth, flower and seed sterility and irregular branching. At the dosage levels used irradiation had no effect on pollen fertility. Seeds of the 1st filial generation were used for both mitotic and meiotic studies. The percentage of the mitotic abnormalities was proportional with the doses. The most dominant type of anomaly was the presence of micronuclei in the different stages of mitosis and in the resting cells. Irradiation affected also other types of anomaliese.g. lagging chromosomes, fragments, bridges...etc. Meiosis, and pollen fertility (2nd generation) were normal.     

Cytogenetic studies of mice exposed to styrene by inhalation.

The data for the in vivo genotoxicity of styrene (STY) are equivocal. To evaluate the clastogenicity and sister-chromatid exchange (SCE)-inducing potential of STY in vivo under carefully controlled conditions, B6C3F1 female mice were exposed by inhalation for 6 h/day for 14 consecutive days to either 0, 125, 250 or 500 ppm STY. One day after the final exposure, peripheral blood, spleen, and lungs were removed and cells were cultured for the analysis of micronucleus (MN) induction using the cytochalasin B-block method, chromosome breakage, and SCE induction. Peripheral blood smears were also made for scoring MN in erythrocytes. There was a significant concentration-related elevation of SCE frequency in lymphocytes from the spleen and the peripheral blood as well as in cells from the lung. However, no statistically significant concentration-related increases were found in the frequency of chromosome aberrations in the cultured splenocytes or lung cells, and no significant increases in MN frequencies were observed in binucleated splenocytes or normochromatic erythrocytes in peripheral blood smears.     

Cytogenetic effect of 238Pu alpha radiation on the germ cells of male mice

A study was made of the yield of reciprocal translocations in stem spermatogonia of mice exposed to alpha-radiation (238Pu) and whole-body acute and chronic gamma-radiation within a wide range of doses and dose-rates. The frequency of reciprocal translocations induced by a single intraperitoneal administration of plutonium nitrate was relatively low and independent of the dose 1.5-18 months after the effect. The yield of the reciprocal translocations induced by chronic effect of gamma-radiation was appreciably lower than that observed after acute irradiation with the same dose and grew linearly with dose. The RBE of alpha-radiation was 10-20 with respect to chronic effect of gamma-radiation.     

Supplementary feeding of horses with processed sorghum grains and oats

Two feeding experiments and in vitro hind gut fermentation tests were carried out to study the effect of processing sorghum grain on digestion of starch and on the gastrointestinal (GI) tract environment of the horse. In experiment 1, 12 yearling Australian stock horses were blocked on the basis of sex then randomly divided into four equal groups, each containing one castrated male and two females of approximately the same age and weight. Horses were offered at 0800 and 1500 h, 3 kg medium quality liverseed grass (Urochloa panicoides) hay and 2 kg of either oats (O), dry rolled sorghum (DRS), steam-flaked sorghum (SFS) or expanded sorghum (ES). Lanthanum was used as external solid marker for the measurements of apparent total tract digestibility. Fresh water was available ad libitum. Horses were allowed 18 days to adapt to the diets followed by a 3-day faecal collection period. Digestibility of dry matter (DM), and acid detergent fibre (ADF) were higher (P<0.01) for dry rolled and expanded sorghum diets. Digestibility of starch was similar across treatments, averaging 0.98 ± 0.009. Faecal pH values were lower (P<0.05) for the sorghum treatments but remained slightly below neutral (≥6.42) for the steam-flaked sorghum. Sub-samples of fresh faeces were supplemented with glucose and used for in vitro measurement of potential lactate production and final pH. The 20 h in vitro pH was also lower (P<0.05) for the steam-flaked sorghum group. All horses maintained good health and completed the experiment successfully.Results of this experiment indicate that digestibility of starch of processed sorghum is comparable to that of oats (0.97 versus 0.98), but processing sorghum grains may produce conditions favourable for lactate production and accumulation.In experiment 2, eight Australian stock horses were used to study changes in pH and accumulation of VFA and lactate in the different parts of the gastrointestinal tract. In this experiment SFS was compared with DRS. Horses were divided into two groups on the basis of sex and body weight. Each group contained two females and two castrated males. The nutritional management of the horses was the same as for the DRS and SFS groups in experiment 1. At the end of the adaptation period horses were slaughtered at intervals of 1.5, 3.0, 4.5, and 6.0 h after morning feeding, one horse per interval per treatment. Samples were collected from the different anatomical regions, and analysed for pH, VFA, and l- and d-lactate. Fermentation in the pre-glandular stomach produced mainly lactic acid and reduced pH to 4.0–4.3 while VFA was the main product in the hind gut. Total and d-lactate were higher (P<0.01) for SFS and a similar trend was observed for total and individual VFA and l-lactate but differences lacked significance (P>0.05). It was concluded that steam flaking of sorghum exacerbates starch fermentation, which may lead to acidosis-related damage to the epithelium of the pre-glandular stomach.     

Cytogenetic effect of mitomycin C and cytosine arabinoside on mice of different genotypes]

Cytogenetic effect of mitomycin C (MC) and cytosine arabinoside (CA) on bone marrow cells of male mice of the strains 101/HY, C57BL/6Y C,3H/SnY and of the (C3HX101) F1 hybrids was studied. The frequencies of cells with chromosome aberrations after the treatment with MC at a 5 mg/kg dose were 54,4%; 41,8%; 40,4% and 26,8% in 101H, B6, C3H/Sn mice and in the F1 hybrids (C3HX101) respectively. The frequencies of cells with chromosome aberrations after the treatment with CA at a 500 mg/kg dose were 25,2%; 17,8%; 10,8% and the 101/H, B6, C3H/Sn mice and in the F1 hybrids (C3HX101) respectively. Both mutagens induced the greatest number of chromosome aberrations in the 101/H strain and the smallest number in the F1 hybrid (C3HX101). A positive correlation was established between the levels of induced and spontaneous chromosome lesions.