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Pro-angiogenic effects of X-rays on murine endothelial cells

Lisiak E., Dziekiewicz M., Meineke V., Bilski M., Janiak M.

Nukleonika

2005

Vol. 50,suppl.2

17-20

Recently, significant attention has been paid to the possibility of thwarting cancer progression by inhibition of neoangiogenesis (formation of new blood vessels) in growing tumors. Although general mechanisms of angiogenesis have been elucidated, virtually nothing is known about the effects of low doses of ionizing radiation on pro-angiogenic properties of endothelial cells. In the present study, we evaluated the effects of a low (0.2 Gy), intermediate (1 Gy), and high (4 Gy) doses of X-rays on a few angiogenesis-related parameters of isolated murine endothelial cells. We show here that 24 to 48 hours after irradiation with 0.2 Gy the cell proliferation was inhibited to a similar extent as after the exposure to 1 Gy. Also, adhesion of the 0.2 Gy-irradiated cells to both gelatin and MatrigelŽ was inhibited 24 hours post-exposure, whereas irradiation with 1 or 4 Gy resulted in the increased adhesion of the cells to these substrata. Similar effects were observed during the "wound" migration assay. Finally, 24 hours after exposure of the cells to 0.2 Gy of X-rays, the surface expression of the â3 integrin subunit was down-regulated, whereas irradiations with 1 and 4 Gy of X-rays resulted in the significantly elevated expression of this subunit. These results indicate that proliferating endothelial cells are sensitive in vitro to relatively low doses of ionizing radiation

Low-level exposures to ionising radiation modulate the anti-tumour activity of murine NK cells

Nowosielska E., Wrembel-Wargocka J., Cheda A., Lisiak E., Janiak M.

Nukleonika

2005

Vol. 50,suppl.2

21-24

Experimental evidence from the recent years indicates that low-level irradiations with X- or gamma rays may inhibit development of both primary and secondary tumours and stimulate the activity of natural anti-tumour immune mechanisms. Natural killer (NK) cells play an important role in anti-tumour defence of the host. In the present investigation cytotoxic activity, production of interferon-ă, and expression of the Fas ligand (FasL) were estimated in the NK splenocytes collected from BALB/c mice whose whole body was pre-exposed to irradiation with 0.1, 0.2, or 1.0 Gy X-rays. The results indicate that cytotoxic activity of the irradiated NK cells was significantly stimulated compared to that of the NK effectors obtained from the sham-exposed mice. This effect was totally abrogated by injection of the anti-asialo GM1 antibody. In addition, compared to the control mice, NK cells obtained from the irradiated animals exhibited reduced surface expression of FasL. Collectively, the obtained results suggest that the inhibitory effect of the low-level irradiations with X-rays on the development of pulmonary tumour nodules may be directly associated with stimulation by such exposures of anti-neoplastic functions mediated by NK cells.