Dose-effect relationship of chromosome aberrations induced by different LET rays at low doses / 中华放射医学与防护杂志

Objective To establish the dose-effect curves of chromosome aberrations in human peripheral blood lymphocytes induced by different LET rays,including 60Co γ-rays,252Cf neutrons,14MeV neutrons and 12C heavy ions at low doses,respectively,in order to assess radiation-induced damages after occupational and accidental exposure.Methods Heparinized whole blood samples were irradiated with the various radiation devices and doses ranged from 0 to 1 Gy with the interval of 0.25 Gy.Conventional chromosome culture method was applied with adding colchicines at the beginning and chromosome specimens were prepared after 48 h incubation.The Metafer scanning system was used for automatical finder of chromosome metaphases.The mathematic models were fitted according to aberration data obtained.Results At the dose range of 0 - 1 Gy,the math models of dic + r were linear for 60 Co γrays and linear-quadratics for 252 Cf neutrons,14 MeV neutrons and 12 C heavy ions.The models of ace were linear-quadratic for 60Co γ-rays and 12C heavy ion beams,and linear for 252Cf and 14 MeV neutrons.The models of total aberrations were linear-quadratic for all types of radiation.Conclusions High LET rays have higher biological effects in inducing chromosome aberrations yields compared with low LET rays.Moreover,the severity of damage is 252Cf ＞ 14 MeV neutrons ＞ 12C heavy ions ＞ 60Co γ-rays in turn.Therefore,in the range of low doses,the dic + r may be a better target of radiation damage for high LET radiation.

Quantitative analysis of angiogenesis and tumor microvascular architecture in microarray of human astrocytoma / 第三军医大学学报

Objective To observe the expression of vascular endothelial growth factor (VEGF) and the parameters of the microvascular architecture in human astrocytomas. Methods A tissue microarray with 168 points including diffuse astrocytoma (WHO gradeⅡ), anaplastic astrocytoma (WHO gradeⅢ), glioblastoma (WHO gradeⅣ) and control tissues was constructed. The expression of VEGF and CD34 was detected by double-labeling immunohistochemistry on tissue microarray. The expression intensity of VEGF and microvascular architecture parameters including vessel number and vessel mean perimeter were analyzed with Image Pro Plus5.0. Results The positive unit (PU) of VEGF has a positive correlation with vessel mean perimeter in diffuse astrocytoma, anaplastic astrocytoma and glioblastoma. Significant differences (P