Objective The purpose of the present study was to observe the changes in CD4+CD25+Nrp1+Treg cells after irradiation with different doses and explore the possible molecular mechanisms involved.
Methods ICR mice and mouse lymphoma cell line (EL-4 cells) was used. The expressions of CD4, CD25, Nrp1, calcineurin and PKC-α were detected by flow cytometry. The expressions of TGF-β1, IL-10, PKA and cAMP were estimated with ELISA.
Results At 12 h after irradiation, the expression of Nrp1 increased significantly in 4.0 Gy group, compared with sham-irradiation group (P<0.05) in the spleen and thymus, respectively, when ICR mice received whole-body irradiation (WBI). Meanwhile the synthesis of Interleukin 10 (IL-10) and transforming growth factor-β1 (TGF-β1) increased significantly after high dose irradiation (HDR) (> or = 1.0 Gy). In addition, the expression of cAMP and PKA protein increased, while PKC-α, calcineurin decreased at 12h in thymus cells after 4.0 Gy X-irradiation. While TGF-β1 was clearly inhibited when the PLC-PIP2 signal pathway was stimulated or the cAMP-PKA signal pathway was blocked after 4.0 Gy X-irradiation, this did not limit the up-regulation of CD4+CD25+Nrp1+Treg cells after ionizing radiation.
Conclusion These results indicated that HDR might induce CD4+CD25+Nrp1+Treg cells production and stimulate TGF-β1 secretion by regulating signal molecules in mice.

A phenomenological model for the dynamics of cell cycle in responding to X-rays

Objective To establish a model to predict the cell-cycle process in response to ionizing radiation.Methods Human choroidal malignant melanoma 92-1 cells were used and the cell cycle distribution of cells was analyzed in 0-96 h after exposure to X-rays.A phenomenological model was constructed based on biological knowledge to describe the cell cycle dynamics in experiments.Results In the present study,a phenomenological model was constructed to describe the cellcycle dynamics of synchronized 92-1 cells in responding to various doses of ionizing radiation.The simulation results obtained with the model were consistent with the experimental data,demonstrating that the model had a good expansibility and could be used to predict the dynamics of cell cycle in responding to ionizing radiation.Further theoretical modeling of the cellcycle dynamics was made and the results were consistent with the simulation.Conclusions A phenomenological model was constructed which could be used to describe the dynamics of cell cycle of cells exposed to ionizing radiation and was supported by the experimental data.Because this model is easy to run by the written code,it has a good expansibility for studying the behaviors of cell populations under various conditions.

长期低剂量电离辐射对放射工作人员血细胞参数的影响

近年来,随着放射防护技术的发展、放射工作人员防护知识的普及、自我保护意识的增强,放射工作人员在日常工作中接触的放射线剂量已处于较低水平,远远低于我国现行的<电离辐射防护与辐射源安全基本标准>(GB18871-2002)[1]中规定的职业人员年有效剂量20mSv/a的限值.为了解长期低剂量电离辐射对放射人员造血系统的影响,于2005-2008年对温州某大型医院放射工作人员及对照者的外周血象进行检测,结果报道如下.

电离辐射场所有害因素对健康的影响研究进展

随着核技术的广泛发展与应用,高能量的电离辐射设备应用越来越多,电离辐射给人类带来巨大利益的同时也产生多种损伤效应,主要包括有确定性效应和随机效应.近年来,随着人们自我保护意识的提高以及放射防护技术的不断完善和发展,监测表明,越来越多的放射工作人员在职业工作中接触低剂量电离辐射(low dose radiation,LDR),人均年剂量当量小于国家剂量限值标准(20mSv)的1/10水平[1-3].

In 1958 the speaker believed that background radiation might cause a fatal cancer. In 1970 he believed there was no risk from background or from the small doses received from diagnostic uses of X-rays. Since 1990 he has come to believe that for good health most people need more radiation than they receive from nature. The talk will emphasize the results of two large British radiologists who entered the field between 1955 and 1979, when compared to all other male English physicians of the same age. Had a 29% lower cancer death rate, a 36% lower death rate from non-cancer and a 32% lower death rate from all causes. The chances of such a health improvement being accidental is less than one in one thousand. The lower death rate from all causes results in more than a three year increase in longevity-the same increase in longevity that would result ff all cancer were curable. The US Government sponsored nuclear shipyard worker study shows that the 28,000 nuclear shipyard workers with the greatest radiation doses, when compared to 32,500 shipyard workers who had no on-the-job radiation, had significantly less cancer and a 24% lower death rate from all causes. That is, the nuclear workers had nearly a three-year increase in longevity.The chance of that health improvement being accidental is less than one in ten million billion. The talk will describe a double blind study to test the hypothesis that a moderate dose of ionizing radiation stimulates the immune system of senior citizens in the I.S. Gulf States where cancer mortality is 25% greater than in the mountains, which have about 300% more background radiation than the Gulf States. Radiation deficiency may be a health problem in many areas of the world.