Reaction of a population of HeLa tumor cells in the stationary stage of growth to irradiation at different rates

The early stages of a repopulation process of HeLa cells under the action of irradiation 5 Gy dose and an influence of a preliminary 0.1 Gy dose irradiation at that process were investigated. As it was shown the fraction of cells with a great proliferation potential appeared in one day after lethal 5 Gy dose irradiation of the resting HeLa cells. If the other irradiation regime was used: 0.1 Gy dose plus 4.9 Gy dose in 3 min after the first action, the part of cells with a great proliferation potential became considerably less.     

The genome instability in the descendants of the Chinese hamster of the cells, irradiated by the low dose and by various intensities of gamma-radiation

The V-79 Chinese hamster cells were irradiated by gamma-rays in dose of 0.5 Gy at powers of doses 0.48 Gy/min (an acute irradiation) and 0.0485 MGy/min (a prolonged irradiation). The acute and prolonged irradiation in a dose of 0.5 Gy enlarges frequency of the appearance of micronucleus (MN). Subsequent cultivation of the irradiated cells during 20 generations enlarges frequency of MN, and for prolonged an irradiation the boosted frequency of MN, is saved during 40-60 generations. After an acute irradiation the number of MN starts to reduce after 20 doublings.     

Effects of single gamma-irradiation on the activity of ornithine decarboxylase in the thymus and pulmonary tissue]

In studying the dose (0.1-6 Gy) and time (2 h to 180 days) dependence of ornithine decarboxylase activity, it was found that deviations from the control were more pronounced in the thymus than in the pulmonary tissue. The radiation effect was a function of dose and time after irradiation. A nonmonotonous type of the dose-response curve was observed 7 days after irradiation: the radiation effect with a low dose (0.1 Gy) was opposite to that with sublethal doses (1-6 Gy).     

Irradiation to ensure quarantine security for Cryptophlebia spp. (Lepidoptera: Tortricidae) in sapindaceous fruits from Hawaii

Studies were undertaken to determine whether irradiation treatment at 250 Gy, an accepted treatment for disinfestation of fruit flies in spindaceous fruits from Hawaii, would also disinfest fruit of two species of Cryptophlebia. Cryptophlebia illepida (Butler) was determined to be more tolerant of irradiation than Cryptophlebia ombrodelta (Lower); therefore, C. illepida was the focus for detailed tests. Using the criterion of success in developing to the adult stage, the pattern of tolerance to irradiation in C. illepida was generally eggs < early instars < late instars < pupae. The most tolerant stage potentially occurring in harvested fruits was late (fourth and fifth) instars. Development to adult was reduced slightly in late instars receiving an irradiation dose of 62.5 Gy, whereas development to adult was dramatically reduced in late instars receiving irradiation doses > or = 125 Gy. No C. illepida larvae receiving an irradiation dose > or = 125 Gy emerged as adults and produced viable eggs, indicating sterility can be achieved at doses well below 250 Gy. In large scale tests, when 11,256 late instars were irradiated with a target dose of 250 Gy, 951 pupated (8.4%) and none eclosed as adults. Within the pupal stage, tolerance increased with age; 7- to 8-d-old pupae (the oldest pupae tested) treated with an irradiation dose of 125 Gy produced viable offspring, whereas those treated with a dose of 250 Gy produced no viable offspring. Irradiation of adults with a target dose of 250 Gy before pairing and mating resulted in no viable eggs. Irradiation of actively ovipositing adult females resulted in no subsequent viable eggs. Therefore, the irradiation quarantine treatment of a minimum absorbed dose of 250 Gy approved for Hawaii's fruits will effectively disinfest fruits of any Cryptophlebia in addition to fruit flies.     

The influence of chronic and of acute irradiation on the polymorphism of RAPD-markers in offspring for irradiated mice

On mice lines BALB/c and CBA/lac was performed the study of molecular-genetics effects in mice progeny after the chronic (dose rate -0.0017 Gy/day, total dose -0.36 Gy) and acute (dose range 1-3 Gy) exposure of y-radiation on the parents. For variability analysis was used technique of amplification DNA with series of random primers (RAPD-assay). Random primers were used as single primer and in mixture of ones. In this work were held the comparative analysis of the genetic radiosensitivity for stem spermatogonia and spermatides. After the acute exposure the dose dependence for levels of polymorphism of RAPD-markers were obtained. After the chronic irradiation, significant differences from control group were obtained only by use primers mixture M1. Comparative analysis of the genetic radiosensitivity of different stages of mice spermatogenesis are display is similar sensitivity of stem spermatogonia and spermatides after doses of irradiation 1 Gy and 3 Gy. Indicated that after irradiation by dose 2 Gy, spermatogonia are more sensitivity than spermatides.     

Low-dose-rate radiation attenuates the response of the tumor suppressor TP53

Acute low-dose irradiation (0.1-1 Gy, 1.33 Gy/min) of cells of a human glioblastoma cell line, A-172, induced a dose-dependent monophasic accumulation of TP53 (formerly known as p53) and CDKN1A (formerly known as WAF1). In contrast, chronic gamma irradiation (0.001 Gy/min) produced a clear biphasic response of accumulation TP53 with the first peak at 1.5 h (0.09 Gy) and the second peak at 10 h (0.54 Gy). Significantly, when the cells were preirradiated with a chronic dose of gamma irradiation for 24 h (1.44 Gy) or 50 h (3 Gy), they no longer responded to an acute challenging dose to produce a dose-dependent response of the TP53 pathway. These findings suggest that chronic irradiation at low dose rate alters the TP53-dependent signal transduction pathway. Wearing away of the TP53 pathway by chronic exposure to radiation may have important implications for radiation protection.     

不同剂量x射线对大鼠精子CRISP2mRNA表达水平的影响

目的：观察不同剂量x射线对大鼠精子CRISP2mRNA表达水平的影响,探讨其在电离辐射所致大鼠精子功能改变中的作用。方法：用吸收剂量为1、2、4、和6Gy的x射线分别照射活体SD大鼠的外生殖系统1…4812、24h后,用PCR技术检测精子CRISP2基因mRNA表达水平;用光学显微镜观察精予活力。以未照射组为对照。结果：4、6GyX射线照射不同时间（1、4、8、12、24h时）后大鼠精子的CRISP2mRNA相对表达量均较对照组显著下降（P．〈0．05）,其中6Gb,照射24小时后相对表达量最低（P〈0．01）,而4Gy照射组与6Gy照射组相比较差异无统计学意义（P〉0．05）;2Gyx射线照射8h后CRISP2mRNA相对表达量下降有统计学意义（P〈0．05）;2GyX射线照射1、4h后及1GyX射线照射不同时间（1、4、8、12、24la）后大鼠精子的CRISP2mRNA相对表达量较对照组下降,但差异无统计学意义（P〉O．05）。1、2GyX射线照射不同时间（1、4、8、12、24小时）及4GyX射线照射（1、4、8h）后,精子活力与正常对照组相比无明显改变（P〉0．05）;4GyX射线照射12、24h后大鼠精子活力显著低于正常对照;6GyX射线照射不同时间（1、4、8、12、24h）后,精子活力明显低于对照组（P〈0．05）。结论：不同剂量X射线照射不同时间可导致SD大鼠精子活力下降,这可能与其下调CRISP2基因的mRNA表达水平有关。     

不同剂量的X-射线全身照射对小鼠健康状况及涎腺的影响

目的:通过直线加速器全身照射昆明小鼠建立辐射损伤模型,探索不同放射剂量对小鼠健康状况及涎腺功能和结构的影响。方法:选取八种不同剂量对昆明小鼠行体外全身照射,于照射后一个月内观察小鼠生长情况、体重变化;照射后一周、一个月检测各组小鼠血象的变化;测定放射半数致死剂量;照射后两个月,测定各组小鼠的唾液流量及唾液淀粉酶含量,并对下颌下腺组织切片行HE染色。结果:13Gy和15Gy照射组小鼠的体重逐渐下降,一周后死亡,其余组小鼠体重最终呈增加趋势。X-射线全身照射的半数致死量为10Gy。照射后一周,照射组小鼠的白细胞数目明显降低,与对照组比较有明显统计学差异(P0.01);在其他血象方面,除了7Gy组外,其他照射组与对照组比较也均有统计学差异(P0.05)。照射一个月后,各照射组小鼠的血象均恢复正常。照射后两个月,9Gy组和11Gy组小鼠的唾液流量及唾液淀粉酶含量均显著低于0Gy组,且11Gy组较9Gy组亦明显降低,差异均有统计学意义(P0.05)。随照射剂量的增加,小鼠的下颌下腺腺泡细胞数目逐步减少,结构排列紊乱,组织损伤逐渐加重。结论:X-射线全身照射引起小鼠健康状况受损,免疫功能减低,损伤程度与放射线强度呈剂量依赖性,小鼠半数致死量为10Gy,该剂量适合建立全身放射损伤模型。     

Calculation and measurement of doses in the surface layers of a phantom when using Tomotherapy

BackgroundThe calculation and measurement on the surface of the skin presents a significant dosimetric problem because of numerous factors which have an influence on the dose distribution in this region.AimThe overall aim of this study was to check the agreement between doses measured with thermoluminescent detectors (TLD) during tomotherapy photon beam irradiation of the skin area of a solid water cylindrical phantom with doses calculated with Hi-Art treatment planning system (TPS).Material and MethodThe measurements of the dose were made with the use of a solid water cylindrical phantom - Cheese Phantom. Two bolus phantoms were used: 5 mm and 10 mm Six different planning treatments were generated. The doses were measured using TL detectors.ResultsIn the case of a tumor located near the surface of the skin, the mean dose for 0.5 cm bolus was - 1.94 Gy, and for 1 cm bolus - 2.03 Gy. For the tumor located inside the phantom and organ at risk on the same side that TL detectors, for a 0.5 cm bolus, mean dose was 0.658 Gy, and for a 1 cm bolus, 0.62 Gy.ConclusionThe analysis of results showed that the relative percentage difference between measured and planned dose in the field of irradiation was less than 10%, while the largest differences were on the board of the field of radiation and outside of the field of irradiation, where the dose was 0.08 Gy to 1 Gy.     

Dynamics of the induced chromosomal instability in welsh onion (Allium fistulosum L.): gamma irradiation of the seeds of different storage periods

The chromosome aberrations in root meristem cells of welsh onion (Allium fistulosum L.) seeds after gamma-irradiation (5 and 10 Gy) of different-aged seeds (7, 19, 31, 43 and 55 months of storage) were studied. The irradiation dose of 5 Gy significantly increased the frequency of aberrant anaphases (FAA) for 31- and 43-months seeds; the dose of 10 Gy significantly increased the FAA in seeds of all age groups. The irradiation of young (7 months) seeds resulted in decreasing of the fraction of bridges to the control level of the old (55-months) seeds for the dose of 5 Gy and below the control level of the old seeds--for the dose of 10 Gy. Some peculiarities of cytogenetic parameters of genome instability and the germinating capacity of the seeds made it possible to suppose that the third year of storage is a critical period for the welsh onion seeds.     

The use of PET/CT in radiotherapy of patients with non-small cell lung cancer

The goal of this paper was to investigate the influence of FDG-PET/CT scan on the modification of staging and irradiation planning in patients suffering from non-small cell lung cancer (NSCLC). Fifteen patients suffering from NSCLC were analyzed by the authors from January, 2008 to July, 2009. The aim of the analysis was to examine the influence of FDG-PET/CT on irradiation planning and on decision-making of the complex oncologic therapy. The FDG-PET/CT scan was carried out in the position of irradiation performed later. For irradiation planning, planning target volumes (PTV) and the organs of risk were contoured on the patients' topometric CT slides as well as on the fused FDG-PET/CT slides. We evaluated how the application of PET/CT modified the stage of the illness, the complex oncologic therapeutic plan, the volume and the localization of the PTV, and the irradiation doses of the organs at risk. The mean and maximum dose of the spinal cord, the mean and V20 dose load of the lungs and the mean dose loads of the heart as well as of the left ventricle were measured. In 8 of 15 cases the stage of the disease and the treatment strategy was modified, since distant metastases were detected by the PET/CT. We evaluated the modification of the PTV and dose load of the organs at risk in 7 cases. According to the PET/CT the PTV was reduced in 5 cases (mean: 393.6 cm3) and was increased in 2 cases (mean: 250.8 cm3). Concerning the risk organs we found that the average (8.8 Gy/9.5 Gy) and maximum (33.4 Gy/36.4 Gy) dose load of the spinal cord increased, while the average (24.5 Gy/13.8 Gy) and V20 (33.7%/22.1%) dose load of the lungs decreased. We likewise found a decrease in the mean dose load of the heart (17.3 Gy/16.8 Gy) and left ventricle (12.9 Gy/9.6 Gy). In the majority of the cases the FDG-PET/CT scan modified the therapeutic decision, the size of the irradiated volume, and the dose load of the lung, the organ at risk causing the most difficulties at irradiation planning, was also reduced. The PET/CT scan plays an essential role in the complex oncologic treatment and irradiation therapy of NSCLC.     

Change in the succinate dehydrogenase activity of peripheral lymphocytes in the rat in early periods following exposure to ionizing radiation

Activity of succinate dehydrogenase (SDH) in peripheral blood lymphocytes of albino mongrel rats was determined during an hour following gamma-irradiation. The highest SDH activity in blood lymphocytes (a 41 per cent increase) was registered 20-30 min following 75 Gy irradiation of the head. With a dose of 20 Gy the SDH response was twice as low. During 1 h following irradiation with a dose of 200 Gy the SDH activity exhibited a 10 per cent decrease.     

Hepatic radiation injury in the rat.

The whole livers of rats were exposed intraoperatively to graded doses (0 to 75 Gy) of 137Cs gamma radiation. At various times (0 to 155 days) after liver irradiation, minimally invasive, nondestructive tests (rose bengal retention and plasma alkaline phosphatase, glutamic-oxaloacetic acid transaminase, glutamic-pyruvic transaminase) were performed on at least half the surviving animals in each dose group to assess developing liver injury. Liver histology was done on animals sacrificed 96 to 100 days after irradiation. Radiation damage to the stomach killed approximately 50% of the animals 30 to 60 days after exposure to doses of 25 Gy or higher. These deaths were significantly reduced when care was taken to shield the stomach during irradiation. Stomach injury did not, however, appreciably affect liver function as measured by rose bengal retention. Whole-liver irradiation to 15 Gy resulted in reduced liver size and minimal histological changes, but did not result in increased rose bengal retention or plasma alkaline phosphatase concentration. The next highest dose group studied (25 Gy) showed significant histological abnormalities and liver injury as measured by increased rose bengal retention and liver enzymes. The latent period for development of hepatic injury, as measured by increased rose bengal retention, was 35 to 42 days and was relatively invariant over the 25- to 75-Gy dose range. Hepatic vein lesions and cellular necrosis were the most prominent histological lesions observed in 25-Gy-irradiated liver.     

Early changes in intracellular ATP concentration after 5 Gy irradiation by routine regimen and regimen modified by low doses (0.1+4.9 Gy)]

Comparative studies were made of immediate (within the first minutes) changes in intracellular ATP concentration after irradiation by different regimens. ATP concentration in cells at a stationary phase of growth increased immediately after irradiation with a dose of 5 Gy, reaching its maximum within 30-40 min. Irradiation with the same total dose, by the regimen of 0.1 + 4.9 Gy at a 3-minute interval between the doses, did not cause alterations in the ATP content in cells. It is concluded that the absence of the increase in the parameter under study (ATP) after irradiation by the latter regimen indicates that preirradiation at a dose of 0.1 Gy inhibits the adequate development of an early response to irradiation with a dose of 4.9 Gy.     

Autoradiographically detected impairment of RNA synthesis pattern in 8-16 cell bovine embryos after irradiation

Early preimplantation bovine embryos at 8- or 16-cell stage were analysed by [5-3H]uridine autoradiography for distribution of newly synthesized RNA after 60Co irradiation with a single dose of 1 Gy, 2 Gy or 4 Gy gamma rays, respectively. Embryos irradiated with a single dose of 1 Gy showed equally decreased synthesis of RNA in nucleoplasma as well as in nucleolus. In embryos irradiated with a single dose of 2 Gy or 4 Gy, RNA synthesis was decreased and localized mostly on the periphery of the nucleus; in both cases of irradiation, the nucleus center being without labelling. In most of embryos irradiated with a dose of 4 Gy, the nucleoli were not labelled, and an increasing occurrence appeared of various nucleus chromatin segregation forms, mainly as its marginalization.     

Bimodal changes in germinability of pea seeds under the influence of low doses of gamma-radiation

Pea seeds (cv. 'Nemchinovskii-85', harvest of 2002, 80%-germination percentage) were exposed to gamma-radiation with doses ranging from 19 cGy to 100 Gy. One week after the irradiation with doses of 19 cGy and 3 Gy. the germination percentage decreased to 58 and 45%, respectively; at doses of 7 and 10 Gy it was 73 and 70% respectively. At greater doses (25, 50, and 100 Gy), germination percentage decreased in proportion. Anomalous changes in seed germination percentage (as a function of irradiation dose) were caused by the redistribution of irradiated seeds between fractions I and II. The measurements of room temperature phosphorescence in air-dry seeds and the phosphorescence of endogenous porphyrines of imbibing seeds showen that the germination decrease after the irradiation with low doses (19 cGy and 3 Gy) was caused by the increase in the number of weak seeds of fraction II, which had high rates of water uptake and suffered from hypoxia under seed coat. Some of these seeds suffocated from hypoxia, and other seeds produced seedlings with morphological defects (such seeds were considered incapable of germination). During storage of seeds irradiated at doses 19 cGy-10 Gy, the recovery of germination percentage (after its initial decrease) was caused by the decrease in seed number in fraction II. The subsequent germination decrease was caused by seed death. The higher was the irradiation dose, the faster were changes in germination percentage during storage of irradiated seeds. Bimodal changes in pea seed germination with the increase of y-irradiation dose has apparently the same origin as the changes in seed germination during accelerated ageing.     

Cyclic nucleotides and lipids in the realization of the radioprotective effect of ceruloplasmin

Ceruloplasmin administered 60 min before irradiation diminished cAMP and cGMP levels, which were increased by irradiation at LD50 and LD100, and normalized cAMP/cGMP ratio in the rat liver during the first 24 h following irradiation with a dose of 6.24 Gy. The content of phospholipids increased and that of cholesterol decreased under the effect of ceruloplasmin leading to normalization of the molar cholesterol/phospholipid ratio in the rat liver on the 7th day of radiation sickness (LD50, 6.24 Gy).     

Effects of X‐ray irradiation on development and reproduction of the oriental tobacco budworm,Helicoverpa assulta (Lepidoptera: Noctuidae)

All stages of the life cycle of Helicoverpa assulta were irradiated with X‐rays to determine the inhibitory dose for development and reproduction to serve as a quarantine treatment. The 100‐Gy dose was effective for irradiation of eggs and larvae, and the 200‐Gy dose was effective for pupae and mixed‐sex adults. When either adult males or females were irradiated, however, 500 Gy was required to prevent the F1 eggs from hatching, and thus single‐sex adults required much higher doses of X‐ray irradiation. To gather confirmatory data applicable to phytosanitary quarantine regulations, pupae—the immature stage most resistant to X‐ray irradiation—were placed inside paprika in boxes for exportation and were irradiated with 300 Gy as a small‐scale confirmatory test. The dose given to 1,007 individual pupae resulted in 12.62 % survival, and 1.79 % of pupae emerged as normal adults; however, these adults produced only a few eggs that did not hatch, suggesting that a minimum dose of 300 Gy of X‐ray irradiation will provide quarantine security for immature H. assulta in paprika exports.     

Suppression of thymic lymphoma induction by life-long low-dose-rate irradiation accompanied by immune activation in C57BL/6 mice

The induction of thymic lymphomas by whole-body X irradiation with four doses of 1.8 Gy (total dose: 7.2 Gy) in C57BL/6 mice was suppressed from a high frequency (90%) to 63% by preirradiation with 0.075 Gy X rays given 6 h before each 1.8-Gy irradiation. This level was further suppressed to 43% by continuous whole-body irradiation with 137Cs gamma rays at a low dose rate of 1.2 mGy/h for 450 days, starting 35 days before the challenging irradiation. Continuous irradiation at 1.2 mGy/h resulting in a total dose of 7.2 Gy over 258 days yielded no thymic lymphomas, indicating that this low-dose-rate radiation does not induce these tumors. Further continuous irradiation up to 450 days (total dose: 12.6 Gy) produced no tumors. Continuously irradiated mice showed no loss of hair and a greater body weight than unirradiated controls. Immune activities of the mice, as measured by the numbers of CD4+ T cells, CD40+ B cells, and antibody-producing cells in the spleen after immunization with sheep red blood cells, were significantly increased by continuous 1.2-mGy/h irradiation alone. These results indicate the presence of an adaptive response in tumor induction, the involvement of radiation-induced immune activation in tumor suppression, and a large dose and dose-rate effectiveness factor (DDREF) for tumor induction with extremely low-dose-rate radiation.