No abstract available.
Radiation, Ionizing

No abstract available.
Genetics ; Radiation, Ionizing

Objective: To investigate the effect of low-dose X-ray ionizing radiation on thyroid function of radiation workers. Methods: From January to December 2021, a total of 1039 medical workers in some tertiary hospitals in Wuhan were selected as the survey subjects, of which 518 radiation workers were selected as the exposure group, and 521 non-radiation workers were selected as the control group. The general conditions of the two groups were collected, and 5 indicators of thyroid function were measured, including total thyroxine (TT(4)) , total triiodothyronine (TT(3)) , free triiodothyronine (FT(3)) , thyroid stimulating hormone (TSH) , and free thyroxine (FT(4)) . The annual cumulative dose of ionizing radiation exposure in the exposure group was collected. Pearson χ(2) test and independent sample t test were used to compare the general conditions, 5 indicators of thyroid function and abnormal rate between the two groups. Linear regression model was used to analyze the correlation between the annual cumulative dose and 5 indicators of thyroid function in the exposure group. Binary logistic regression was used to analyze the influencing factors of thyroid dysfunction in the exposure group. Results: The TT(4) levels of the workers in the control group and the exposure group were (7.95±1.07) μg/dl and (8.26±1.41) μg/dl, respectively, and the FT(4) levels were (16.33±2.19) pmol/L and (17.15±2.42) pmol/L, respectively, the rate of thyroid dysfunction was 4.80% (25/521) and 8.49% (44/518) , and the above differences were statistically significant (P<0.05) . Linear regression analysis showed that the annual cumulative dose of the exposure group was significantly correlated with TT(4), TT(3), FT(4), and TSH (P<0.05) . For every 1 mSv increase in the annual cumulative dose, TT(4) increased by 1.661 μg/dl, FT(4) increased by 1.422 pmol/L, TT(3) decreased by 0.113 ng/ml, and TSH decreased by 0.731 μIU/ml. Binary logistic regression analysis showed that the older the radiation workers, the higher the risk of thyroid dysfunction (OR=1.080, 95% CI: 1.016-1.148, P=0.013) ; the greater the annual cumulative dose, the higher the risk of thyroid dysfunction (OR=6.400, 95%CI: 1.796-22.811, P=0.004) . Conclusion: The annual cumulative dose of low-dose X-ray ionizing radiation is positively correlated with thyroid function TT(4) and FT(4) of radiation workers, and negatively correlated with TT(3) and TSH; the greater the age and annual cumulative dose, the higher the risk of thyroid dysfunction.
Humans ; Triiodothyronine ; Thyroxine ; Thyroid Gland/radiation effects* ; X-Rays ; Thyrotropin ; Radiation, Ionizing

Hormesis is the generally-favorable biological responses to low exposures to toxins and other stressors. Radiation hormesis is the theory that ionizing radiation is benign at low levels of exposure, and that doses at the level of natural background radiation can be beneficial. The purpose of this study is to reveal the hormetic effect of low-dose radiation of ionizing radiation on the ovarian follicles of 4-week old female mice. Mice were grouped into control group, 2 cGy irradiated group, 2 cGy and 2 Gy irradiated group (2 cGY pre-exposure group), and 2 Gy irradited group. Mice were sacrificed by cervical dislocation 24 hours after irradiation, removed ovaries, fixed in neutral formaldehyde solution for 24 hours, embedded with paraffin, stained with hematoxylin and eosin and TUNEL immunohistochemically, and observed light microscopically the atretic follicles and normal follicles in various follicular developmental stages. In this experiment, the ratrio of atretic follicles to entire follicles in an ovary increased significantly in 2 Gyirradiated group compared with 2 cGY pre-exposure group, and the ratio of normal follicles to the entire follicles in an ovary in all the developmental stages were increased significantly in the 2 cGY pre-exposure group compared with 2 Gy-irradiated group. These results mean that low-dose radiation pre-exposure can induce the hormetic effect in the developing ovarian follicle.
Animals ; Background Radiation ; Dislocations ; Eosine Yellowish-(YS) ; Female ; Follicular Atresia ; Formaldehyde ; Hematoxylin ; Hormesis ; Humans ; In Situ Nick-End Labeling ; Mice ; Ovarian Follicle* ; Ovary ; Paraffin ; Radiation, Ionizing ; Rats*

OBJECTIVETo investigate the effect of 0.1 Gy X-ray irradiation on the gene expression profiles in normal human lymphoblastoid cells using gene microarray and to explore the possible mechanism of the biological effect of low-dose irradiation.

METHODSThe NimbleGen 12×135 K microarray corresponding to 45033 genes was used to analyze the gene expression profiles in AHH-1 cells cultured for 6 h and 20 h after 0.1 Gy X-ray irradiation. A gene was identified as the differentially expressed gene if the ratio between its expression levels in irradiation group and control group was higher than 2 or lower than 0.5. RT-PCR and real-time PCR were used to confirm some differentially expressed genes.

RESULTSThere were 760 up-regulated genes and 1222 down-regulated genes in the cells at 6 h after 0.1 Gy X-ray irradiation, while there were 463 up-regulated genes and 753 down-regulated genes at 20 h after 0.1 Gy X-ray irradiation; there were 92 differentially expressed genes in common. The expression of GADD45A, CDKN2A, and Cx43 measured using gene microarray was confirmed by RT-PCR and real-time PCR.

CONCLUSIONLow-dose irradiation can affect the expression of many functional genes, which provides a basis for the research on the mechanism of radiation damage.

Cell Line ; Humans ; Lymphocytes ; radiation effects ; Oligonucleotide Array Sequence Analysis ; Radiation Dosage ; Radiation, Ionizing ; Transcriptome ; X-Rays

OBJECTIVETo explore the effect of low doses X-ray on proliferation of hippocampal pyramidal cell in the area of CA1 in prenatal rat and its relevant mechanism.

METHODSA total of 25 pregnant rats were randomly divided into four experimental groups and one control group. The experimental groups, in a duration of consistent 18 days, respectively received different doses as follows: 0.015 mGy/d, 0.03 mGy/d, 0.06 mGy/d and 0.09 mGy/d. The control group received sham radiation. To observe the density and width of hippocampal pyramidal cell in the area of CA1 by HE stained and observe the expression of the ERK1/2 by IHM.

RESULTS(1) Except C group, all other groups presented increment in width of the level of hippocampal pyramidal cell, compared with C group; H group, M group, L1 group and L2 group were higher than that (F value respectively were 8.475, 33.42, 14.395, 44.955; P value respectively were 0.002, 0.048, 0.030, 0.012). But the phenomenon of inhomogeneity in width in H group was observed, at the same time, the density of cell in H group became looser (F = 4.466, P = 0.017). (2) The expression of ERK1/2 in the hippocampus CA1 was seen in cytoplasm of every group, the average optical density of positive ERK1/2 protein significantly increased in L1 group and L2 group, compared with control group respectively (F value respectively were 4.561, 4.103, P value respectively were 0.044, 0.035).

CONCLUSIONLow doses X-ray could promote proliferation of hippocampus CA1 cell in prenatal. The reason could be the increment of the ERK1/2 protein induced by X-ray. When the doses reached 0.09 mGy/d, the excesses proliferation phenomenon was observed.

Animals ; Cell Proliferation ; radiation effects ; Female ; Hippocampus ; cytology ; radiation effects ; Male ; Maternal Exposure ; Neurons ; cytology ; radiation effects ; Pregnancy ; Pyramidal Cells ; cytology ; radiation effects ; Radiation, Ionizing ; Rats ; X-Rays

Radiation necrosis is the main obstacle for radiosurgery delivering high dose ionizing radiation inhomogeneously into small field of lesion with spatial accuracy. The complication probability is closely related to dose-volume effect. To reduce the complication rate, the optimum dose should e prescribed for the isodose curve enclosing the target lesion according to the lesion volume and isodose fall-off. However, the shape, volume and isodose fall-off of the lesions are different from each other. To choose the optimum doses for radiosurgery in each case, it is necessary to have a reasonable model for predicting dose-volume effects. Flickinger developed an integrated logistic formula using normalized total dose(NTD) as a reasonable model to predict complications from gamma knife radiosurgery. The authors developed a computer program to calculate the risk probability using that formula. As previously emphasized, the risk probability derived from the formula is useful and indispensable as a guidance to dose prescription in gamma knife surgery.
Necrosis ; Prescriptions* ; Radiation, Ionizing ; Radiosurgery*

PURPOSE: The purpose of this study was to evaluate the relationship between radiation-induced activation of DNA repair genes and radiation induced apoptosis in A431 cell line. MATERALS AND METHODS: Five and 25 Gys of gamma radiation were given to A431 cells by a Cs-137 cell irradiator. Apoptosis was evaluated by flow cytometry using annexin V-fluorescein isothiocyanate and propidium iodide staining. The expression of DNA repair genes was evaluated by both Northern and Western blot analyses. RESULTS: The number of apoptotic cells increased with the increased radiation dose. It increased most significantly at 12 hours after irradiation. Expression of p53, p21, and hRAD50 reached the highest level at 12 hours after 5 Gy irradiation. In response to 25 Gy irradiation, hRAD50 and p21 were expressed maximally at 12 hours, but p53 and GADD45 genes showed the highest expression level after 12 hours. CONCLUSION: Induction of apoptosis and DNA repair by ionizing radiation were closely correlated. The peak time of inducing apoptosis and DNA repair was 12 hours in this study model. hRAD50, a recently discovered DNA repair gene, was also associated with radiation-induced apoptosis.
Apoptosis* ; Blotting, Western ; Cell Line* ; DNA Repair* ; DNA* ; Flow Cytometry ; Gamma Rays ; Humans* ; Propidium ; Radiation, Ionizing

OBJECTIVES: Although ionizing radiation is recognized as being harmful to humans, debate continues regarding the effects of low doses of ionizing radiation. Some studies have reported that low doses of ionizing radiation have a bio-positive effect, namely hormesis, and many researchers have attempted to find concrete and scientific evidence to prove this. To determine whether the discrepancy in effects of low doses of ionizing radiation arises from genetic differences, a study with a multicellular organism system such as fruit flies is needed. METHODS: After irradiation at a low-dose rate of gamma radiation with chronic (0.2 Gy) and acute (0.2, 0.75 and 4 Gy), the pupa rate, eclosion rate and life span were examined with various wild type strains of Drosophila melanogaster such as W1118, Oregon-R, and Canton-S. RESULTS: The life span of Oregon-R exposed to both acute and chronic, low-dose radiation (0.2 Gy) was increased. Although there was some difference in the longevity between the acute and chronic radiation rate, no other differences were found. In Canton-S, only acute dose (0.75 Gy) increased the life span, but it did not in W1118. CONCLUSIONS: Although there were some differences between wild type fruit fly strains in longevity, the low doses of ionizing radiation extended the life span of D. melanogaster. Further studies need to be carried out to explain the difference according to dose and dose rate of radiation in the tested strains.
Diptera ; Drosophila ; Drosophila melanogaster ; Fruit ; Gamma Rays ; Hormesis ; Humans ; Longevity ; Pupa ; Radiation, Ionizing

PURPOSE: The aim of the present study was to identify the radiation hazards to vascular surgeons and scrub nurses working in mobile fluoroscopy equipped hybrid vascular operation rooms; additionally, to estimate cumulative cancer risk due to certain exposure dosages. METHODS: The study was conducted prospectively in 71 patients (53 men and 18 women) who had undergone vascular intervention at our hybrid vascular theater for 6 months. OEC 9900 fluoroscopy was used as mobile C-arm. Exposure dose (ED) was measured by attaching optically stimulated luminescence at in and outside of the radiation protectors. To measure X-ray scatter with the anthropomorphic phantom model, the dose was measured at 3 distances (20, 50, 100 cm) and 3 angles (horizontal, upward 45°, downward 45°) using a personal gamma radiation dosimeter, Ecotest CARD DKG-21, for 1, 3, 5, 10 minutes. RESULTS: Lifetime attributable risk of cancer was estimated using the approach of the Biological Effects of Ionizing Radiation report VII. The 6-month ED of vascular surgeons and scrub nurses were 3.85, 1.31 mSv, respectively. The attenuation rate of lead apron, neck protector and goggle were 74.6%, 60.6%, and 70.1%, respectively. All cancer incidences among surgeons and scrub nurses correspond to 2,355 and 795 per 100,000 persons. The 10-minute dose at 100-cm distance was 0.004 mSv at horizontal, 0.009 mSv at downward 45°, 0.003 mSv at upward 45°. CONCLUSION: Although yearly radiation hazards for vascular surgeons and scrub nurses are still within safety guidelines, protection principles can never be too stringent when aiming to minimize the cumulative harmful effects.
Fluoroscopy* ; Gamma Rays ; Humans ; Incidence ; Luminescence ; Male ; Neck ; Prospective Studies ; Radiation, Ionizing ; Surgeons