International journal of radiation biology
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Int. J. Radiat. Biol. · Feb 2001
Adenovirus-mediated wild-type p53 gene expression radiosensitizes non-small cell lung cancer cells but not normal lung fibroblasts.
We compared the ability of adenoviral-mediated wild-type p53 RPR/INGN201(Ad5/CMV/p53) to radiosensitize non-small cell lung carcinoma (NSCLC) and normal lung fibroblast cells. ⋯ Our data indicate that therapy using Ad5/CMV/p53 and irradiation in combination is more effective than either treatment when used alone on NSCLC cells, is not limited to cells with defective endogenous p53, and does not enhance the radiosensitivity of normal cells.
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Int. J. Radiat. Biol. · Apr 1997
Radiation-induced apoptosis in the rat spinal cord: lack of equal effect per fraction.
This study assessed the apoptotic response in the rat spinal cord following split-dose and fractionated irradiation. The cervical spinal cord (C2-T2) of adult female Fisher 344 rats was irradiated with a single, two, three or four daily fractions of 8 Gy, or two doses of 8 Gy separated by an interval of 0, 1, 2 or 4 h, or 1, 2, 3, 6, 10, 14, 28 or 63 days between two doses. Animals were sacrificed at 0, 4, 8, 12 and 24 h after each final 8-Gy dose, and the percentage of apoptotic glial cells was scored histologically according to specific morphological features of apoptosis. ⋯ TAY from the second 8-Gy dose given at 0, 1, 2, 4, 24 and 48 h was 0.93 +/- 0.03, 2.32 +/- 0.10, 3.26 +/- 0.10, 2.57 +/- 0.11, 3.67 +/- 0.22 and 3.48 +/- 0.13% respectively versus 9.04 +/- 0.34% after the initial 8 Gy (p < or = 0.001). TAY = 7.01 +/- 0.33% from the second 8-Gy dose given at an interval of 3 days was significantly greater than that given at 1 or 2 days (p < 0.0001), but significantly less than that of 9.84 +/- 0.33% given at 14 days (p = 0.0003), suggesting recovery of the apoptotic response occurring at 3 days and completed at 14 days after the initial 8 Gy dose. For radiation-induced apoptosis in the rat spinal cord, we conclude that the concept of equal effect per fraction is not applicable, and that split doses are more effective than the same dose given as a single fraction.
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Int. J. Radiat. Biol. · Oct 1995
Oxidative stress in radiation-induced interstitial pneumonitis in the rat.
The involvement of free radical metabolism in the pathogenesis of interstitial pneumonitis was investigated in an animal model. Male Wistar rats were irradiated at the thoracic region by gamma-rays from a 60Co source. Histopathological examination confirmed that 50% of the rats developed pneumonitis between 2 and 8 weeks following a single dose of 14 Gy. ⋯ In lung mitochondria, however, the levels of these two enzymes were not significantly altered. On the contrary, lipid peroxidation and superoxide dismutase, as well as catalase activities in lung tissue in the non-pneumonitic group of the irradiated rat were comparable with that of control animals. The results indicate that free radical-induced oxidative stress following thoracic irradiation may be one of the causative factors in the development of interstitial pneumonitis.
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Int. J. Radiat. Biol. · Mar 1993
Thermal properties and fluidity of human erythrocyte membranes in diabetes mellitus.
Exposure of human erythrocytes to elevated temperatures induces a decrease in stability of the cell membrane. Thermally induced haemolysis of erythrocytes from patients with type 1 diabetes and from healthy control individuals was measured as a function of duration of exposure to heat between 48.0 and 54.0 degrees C. Results indicate that the thermosensitivity of erythrocytes from patients with type 1 diabetes is lower than for control individuals. ⋯ The steady-state fluorescence anisotropy measurement of TMA-DPH for each step of haemolysis was employed as a parameter characterizing membrane fluidity. We found that 'diabetic' erythrocyte membranes had significantly decreased fluidity. The relationship between fluidity and rate of haemolysis indicates that the rate-limiting step in the haemolysis reaction involves the rupturing of the membrane bilayer.