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The effects of magnesium on the genotoxicity of cadmium chloride and lead acetate were investigated. The DNA repair as the genotoxicity test was determined in cultured sheep lymphocytes treated with the heavy metals in combination with UV-induced DNA damage. Excision repair was performed by incorporation of [³H]-thymidine into DNA of lymphocytes synchronised with hydroxyurea in G₁/S phase. The results show that DNA repair was strongly affected by cadmium (Il) but only slightly in cells treated with lead, indicating rather mitogenic properties. Repair inhibition made by cadmium was restored after treatment of lymphocyte cultures with 0.4 mM. of magnesium chloride for six hours. In conclusion, genotoxicity of Cd or Pb to lymphocytic DNA was markedly decreased by the presence of Mg in culture media.
Lymphocyte blastogenesis was determined by ³H-thymidine incorporation assay after stimulation of the cell cultures with mitogens: Concanavalin A, phytohaemagglutitin, and pokeweed mitogen. BIV and/or BLV infection were associated with significant changes in lymphocyte blastogenesis to mitogens. The highest responses to all three mitogens were shown by 3 to 4.5 months after infection when compared to control animals, and thereafter were depressed at the end of the experiment Stimulated lymphocytes revealed in 20 - 50 fold increase in blastogenesis over background based on the unstimulated cells. These results demonstrated that a function impairement of lymphocytes can be observed in the course of BLV and/or BIV infection.
В описанном тесте применяли реагенты, изготовленные в Отделе биохимии Ветеринарного Института в Пулавах. Антиген вируса из клеточной линии FLK-BLV и очищали техникой ультрацентрифугирования. Кроличьи иммуноглобулины против IgG крупного рогатого скота конъюгировали со щелочной фосфатазой при помощи глютарового альдегида. Вступительные определения антител в сыворотках крупного рогатого скота и овец, а тоже в молоке коров, свидетельствуют о большой чувствительности и удовлетворительной специфичности стета. По сравнению с тестом иммунодиффузии тест ELISA является около 100 раз более чувствительным, а в лейкозном стаде констатировали большее число положительно реагирующищх животных. При использовании теста ELISA показалось возможным определение антител в молоке коров, хотя большинство проб реагировало отрицательно в иммунодиффузии.
The influence of non-cytopathic and cytopathic strains of M-PI₃ parainfluenza virus on bovine leukaemia virus (BLV) replication was assessed. It was found that enzymatic activity of BLV revertase from FLK cells was 21 471 cpm, 23 127 cpm, 12 406 cpm and 2506 cpm after 24, 48, 72 and 96 hours, respectively. In FLK cells infected additionally with the cytopathic strain M-PI₃ the number of cpm was lower than in that of control cells (FLK uninfected with M-PI₃) and was 16 367, 17 329, 20 987 and 4637 after 24, 48, 72 and 96 hours, respectively. The highest activity of BLV revertase from FLK cells infected also with the non-cytopathic strain of M-PI₃ was obtained after 24 and 48 h; the findings were: 26 451 cpm and 28 319 cpm, respectively. This activity after 72 h was 18 952 cpm and after 96 h 3421 cpm. The yield of BLV from FLK cells infected additionally with the non-cytopathic strain M-PI₃ was higher by 37,9 per cent after 24 h p.i. and by 38,8 per cent after 48 h p.i. than in that received from FLK control cels. The results have indicated the synergetic activity of BLV and non-cytopathic M-PI₃ viruses cultivated in FLK cells.
The aim of the study was to compare the effectiveness of calves infected with bovine leukaemia virus with that gained after the administration of FLK-BLV cells and lymphocytes of a leukaemic cow. The experiment was carried out on two groups of animals aged from 6 to 8 months. Each group of the cows was infected intravenously with the same dose of 1.2 x 105 FLK cells or lymphocytes. The third group involving two animals served as the control one. The sera of calves were tested at 2, 4, 6 weeks and 2, 3, 4 and 5 months after infection. The geometric mean titer of FLK infected calves was 3.9; 50.8; 101.6; 80.0; 64.0; 63.5 and 51.2 and in the group infected with lymphocytes - 0.0.; 511.6; 776.0; 2051.0; 1559.0; and 504.1, respectively. Serological examinations by means of the ELISA test revealed specific antibodies at two weeks after infection in the FLK group and at four weeks in the lymphocyte treated group. The highest titers were observed at six weeks in the sera of calves of the first group and at two months in case of the second group. It was found that the highest titer of antibodeis in the calves infected with lymphocytes was 20-fold higher than that of FLK cells infected animals.
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