Objective To investigate whether or not adaptive response of the 2BS and A549 cells induced by low dose irradiation.Moreover,to analyze the relationship between the adaptive response and cells cycle regulation. Methods 1.The dose-survival curves of A549 and 2BS cells were figured by colony formation and typan blue cell staining.2.Flow cytometry was used to analyze the cell cycle after the different doses irradiation. Results 1. The adaptive response induced in 2BS cells by low dose,while it was not induced in A549 cells.2.G2 phase arrest of 2BS cells after 75mGy X-ray plus 4Gy 60Co γ-ray irradiation appeared in 30 minutes,and cell cycle recovered in 24 hours. Conclusion The adaptive response of 2BS cell could be induced by low dose irradiation,and there was close relationship between the adaptive responses and the regulation of cell cycle.

Objective To study the effects of helicase-like transcription factor (HLTF)transfection on DNA repair protein level in radiation-induced apoptotic cells.Methods Human lung carcinoma A549 cells were cultured and transfected with FLAG-tagged wild type HLTF (wild type HLTF transfection group),RING structure domain (ubiquitin conjugating region) mutatation HLTF expressing plasmid (mutant transfection group),empty plasmid (congtrol group) respectively.And the other cells were used as mock transfection group.All cells were irradiated with 15 Gy of 60Co γ-rays to induce apoptosis.Western blotting was used to detect the protein levels of the DNA repair proteins HRAD17 and HRAD52 in the transfected cells.Results The levels of HRAD17 and HRAD52 in the wild type HLTF transfection group was significantly lower than that of the control group.There was no significant difference in HRAD17 and HRAD52 levels between the mock transfection group and ubiquity in conjugating region mutation group.complexes of HLTF and HRAD17 and HRAD52 could be found in the irradiation-induced cells.Conclusions HLTF mediates the degradation of HRAD17 and HRAD52 in the irradiation-induced apoptotic cells possibly by the interaction of the protein complex causing ubiquitination of the repair proteins.

Objective To study the expression of membrane molecules of T lymphocytes of cord blood after low dose irradiation(LDI). Methods Freshly isolated lymphocytes from cord blood were irradiated with 62mGy gamma-ray. At different time(4h; 12h;24h) after irradiation, the changes of TCR+, CD3 +, CD4 +, CD8 + cells were examined by flow cytometry with direct immunofluorescence, respectively. Results The proportion of CD3 +, TCR+ /CD3 +; CD4 +, CD8 + cells increased significantly after LDI,the most obvious enhancement was noted in the 24h experimental group were no significant changes in the ratio of CD4 to CD8. Conclusions It is suggested that expedition of the maturation, activation and signal transudation of T lymphocytes from cord blood can be induced by ir- radiation with 62mGy gamma-ray The reconstruction of immune functions after cord blood transplantation may be ac- celerated, enhancing the graft versus leukemia(GVL)effect and preventing the tumor from relapsing.

Objective To observe and study the late effects of intrauterine exposure to irradiation.Methods A 16-year-old girl,borne by a woman exposed to 60Co irradiation during the Xinzhou radiation accident 16 years ago underwent inquiry,general medical examination.Conventional chromosome aberration analysis and fluorescence in situ hybridization (FISH) were used to examine non-stability and stability chromosome aberrations,and China revised Wechsler Intelligence Scale for Children (C_WISC)was used to detect IQ level.Results Inquiry revealed no history of carcinoma and no family history of hereditary diseases.The girl often caught cold when she was a child,but she hadn' t any other diseases.Menarche occurred when she was 12 years old,and she had not suffered from dysmenorrhea.Her development of body frame constitution was normal.She could not carry out addition and subtraction,but she could make simple verbal communication,writing and even reciting text.The results of the routine lab examination were within the normal range.Unstable chromosome aberrations were not shown,and the chromosome translocation rate was 2.3%.The dose that induced the chromosome injury was deduced as 0.81 Gy.The biological dose of the radiation that she was exposed to was inferred to be 1.85 Gy when she was in ther mother's uterus.Ultrasonic sound showed nodular goiter and no malignant change.China's revised Wechsler Intelligence Scale for Children (C_WISC) test results showed that speech,operation and full-scale IQ was 51,50,and 46 respectively.The total intelligence was better than 0.01% ,and worse than 99.90% of the population.Conclusions Exposure in utero does not affect the body frame constitution development after birth of the fetus,but mental retardation is clear.No evidence of any tumor can be found for the children exposed to radiation before their birth.

Objective To investigate the late effect of radiation on child-bearing women,through observing "Fang",a 19-week-pregnant woman at age of 23,who was exposed to 60Co radiation in Shanxi Xinzhou radiation accident in November,1992 and diagnosed as moderate bone marrow type acute radiation sickness and recovered after 16 year of follow-up treatment.Methods Clinical data including medical history,physical examination,laboratory data,imaging findings and consulting relevant departments were reviewed.Results The followed-up woman "Fang" often felt weak and caught cold after recovery.When she was 32 years old (9 years after radiation),her hair turned grey,but without hair loss.Her menstrual quantity was lessened since 31 years old (8 years after radiation).She was remarried and pregnant twice in the same year.At the first time she underwent artificial abortion and the second child suffered from intrauterine death after 6 months of pregnancy.The physical examination found bilateral degree Ⅰ thyroid enlargement and sparse armpit hair.The laboratory test showed the increased levels of triiodothyronine,thyroxine and anti-thyroid peroxidase antibody (TMAb) and the decreased thyroid stimulating hormone (TSH).Unstable chromosome aberrations were totally lost and stable aberrations in chromosomes were detected by fluorescence in situ hybridization (FISH).The dose estimated with the residue chromosome aberration was 0.76 Gy.Other laboratory results were normal.Ultrasonic test showed diffuse lesion in bilateral thyroid and multiple cystic nodules in right lobe of thyroid,which was considered to be nodular goiter.The examination of bone mineral density (BMD) showed osteoporosis from the second to the fourth lumber vertebra.There were no diseases associated with radiation based on the consultation from related departments.Conclusions Intrauterine death after 6 months of pregnancy might be associated with the previous exposure.There is no evidence of malignant tumor,but non-cancerous diseases are obvious.

Objective To reconstruct the absorbed dose for the individual who was accidentally exposed in uterus 16 years ago.Methods Peripheral blood samples were taken from the victim and her mother.The dicentric and centric ring chromosome aberrations were analyzed with conventional method,the micronucleus was observed with cytokinesis-block micronucleus method,and fluorescence in situ hybridization (FISH) with chromosomes 1,2 and 4 painting probes were used for translocation detection.Dose was estimated according to the standard dose-response curves previously established.Results No unstable chromosome aberrations and normal micronucleus frequencies were observed in two persons 16years after the accident.Against the established dose-response curves with FISH,the doses to the mother and her daughter were 0.76 Gy (95% GI 0.41-1.00 Gy) and 0.61 Gy (95% CI 0.44-0.86 Gy),respectively.Because the biological dose estimated for the mother 1 month after the accident was 2.30 Gy (95% CI 2.07-2.50 Gy),the dose correction factor was 3.03 for dose estimation 16 years later.The estimated dose in uterus to the victim was 1.85 Gy (95% CI 1.33-2.61 Gy).Conclusions The estimated dose to the individual accidentally exposed in uterus 16 years ago can be obtained according to the dose correction factor of the mother with FISH method.