Aminotransferase and lactate dehydrogenase activity in the blood of dogs exposed to the joint action of external gamma- and internal alpha-radiation

After the effect of external gamma-radiation (6.5 to 51.6 mC/kg) and inhaled 239Pu submicron oxide, containing 25% of 241Am, (approximately 7 to 10 kBq/kg) delivered separately and in a combination, activities of alanine-aspartate aminotransferase and lactate dehydrogenase changed in an undulatory manner tending to increase at later times; the change rating was a function of type and level of radiation as well as the time lapsed from the onset of exposure. The combined effect of gamma- and alpha-radiation did not exceed the additive effect of the two factors delivered separately.     

Characteristics of osteosarcomas and morphological changes in the rat thymus during the combined action of gamma-radiation and 239Pu

Under the combined effect of external gamma-irradiation and 239Pu, osteosarcomas occur more frequently and at earlier times, and have more pronounced multicentric pattern of growth and metastatic spreading than occurs with the two agents delivered separately. The difference is in the increased development of tumors and the decreased osteogenesis. Tumor carriers develop atrophy of thymus lymphoid tissue more frequently than normal ones.     

Quantitative evaluation of the combined effect of external gamma radiation and internal alpha radiation from 239Pu based on biochemical indices of the organs of the rat immune system

The combined effect of external gamma-radiation (137Cs, 103-26 mC/kg) and incorporated alpha-radiation (239Pu nitrate, 93-9.3 kBq/kg body mass) was estimated by changes in the nucleic acid metabolism and the number of cells in rat thymus, spleen and bone marrow. The data obtained were processed using a model of multiplicate action of the factors which is equivalent, in the case of low effects, to a traditional model of additive effects. The results of the combined action of the two factors may be estimated by the coefficient of the interaction and the coefficient of the enhancement of the effects.     

Combined effect of 239Pu and external gamma radiation on pregnant and lactating rats

Exposure of pregnant and lactating rats to external gamma-radiation (12.9-103.2 mC/kg) caused 239Pu redistribution within their bodies. The increase in the transfer of 239Pu to the progeny was maximum after gamma-irradiation of pregnant rats with the dose of 25.8 mC/kg. The decrease in the intake of 239Pu by the progeny was maximum after gamma-irradiation of lactating rats with the dose of 12.9 mC/kg. With the combined effect of gamma- and alpha-radiation gamma-radiation was shown to play the major role in the embryos death.     

Functional state of the thyroid gland in sheep at a remote period after single administration of Sr-90, Pu-239 and their mixture

Five years after single intravenous injection of a mixture of 239Pu and 90Sr to semifine-wool sheep (7.4 kBq/kg + 185 kBq/kg) the iodine-fixing and hormone secreting functions of the thyroid gland were inhibited; where 90Sr alone was injected in the above dose inhibited was the hormone-secreting function only. Since 239Pu alone did not cause such alterations, the observed remote effect was attributed to the effect of the incorporated 90Sr.     

Removal of monomeric 239Pu from bones and liver by liposome-encapsulated pentacin

Dependence of monomeric 239Pu removal from the liver and skeleton by liposome-encapsulated pentacine on dose and concentration of encapsulated chelate was studied in rats. It has been shown that the liposome-encapsulated pentacine (LP) removed 1.5-2.5 times as much 239Pu as free chelate (FP). Dose-effect dependences were logarithmic. The distinction between LP and FP in 239Pu removal from the liver was maximum when chelate had been used in a dose of 50 mumol/kg, with the dose effect upon injection in a large number of liposomes (200 mumol of lipids/kg) being 1.8 times as high as upon injection in smaller number of liposomes (50 mumol/kg). LP doses varying from 100 to 400 mumol/kg, there were no differences between two types of LP; with a LP dose of 400 mumol/kg its action is a bit stronger than that of the chelate. The distinction between LP and FP in 239Pu removal from the skeleton is the greatest with chelate doses exceeding 100 mumol/kg. The use of liposomes in combination with concentrated chelate solution is more effective. Possible interpretation of the features revealed are discussed.     

Degree of damage to dogs from a combination of external gamma-radiation and inhalation of submicron 239Pu dioxide evaluated by integral indices

The possibility of quantitation of the organism affection by the combined effect of external gamma-irradiation (103.2 and 51.6 mC/kg) and succeeding inhalation of different amounts of 239Pu submicron dioxide was shown on 55 mongrel dogs using the following criteria: the rate of extracellular fluid accretion and the body weight loss.     

Alkaline phosphatase and transaminase activity in the liver and blood serum of rats in the late periods following combined exposure to external gamma radiation and alpha radiation from plutonium-239

A study was made of activity of alkaline phosphatase and alanine- and aspartate aminotransferase in rat liver and blood serum at remote times after external gamma-irradiation combined with internal exposure to 239Pu nitrate delivered in two chronically effective doses. The radionuclide was shown to be mainly responsible for the changes observed in activity of the enzymes under study. The degree to which the changes were manifest depended upon dose of plutonium administered.     

Combined prophylactic administration of riboxin and algisorbum at 239Pu intake into gastrointestinal tract of rats

The present study is devoted to the investigation of effectiveness of combined prophylactic administration of riboxin and algisorbum at 239Pu per oral intake and possible mechanisms of their interaction, and also to comparative estimation of effectiveness of combined administration of the preparations at per oral and intra peritoneal methods of riboxin introduction. The experiments have been carried out on white nonlinear rats. Riboxin (per oral and intra peritoneal) and algisorbum (per oral) have been introduced to the rats both separately and combined before per oral 239Pu introduction. Data obtained as a result of the investigation showed that combined riboxin and algisorbum introduction into gastrointestinal tract before 239PU intake lead to greater decrease in the plutonium content in the organs of deposition than single algisorbum administration. Intra peritoneal riboxin introduction reduced effectiveness of per oral algisorbum administration in plutonium binding in GI tract. Efficiency of combined riboxin and algisorbum administration in the reduction of 239Pu accumulation in organs depends on the method of riboxin introduction and develops only at per oral introduction.     

Effect of external gamma radiation on shortening the life expectancy and rates of the formation of absorbed doses from incorporated 239Pu in dogs

External gamma irradiation of dogs with doses of 103.2 and 51.6 mC/kg combined with the effect of inhaled plutonium-239 accelerates the formation of absorbed doses in secondary organs of the radionuclide deposition by 41.7 and 2.4 times, respectively, whereas the dose of 25.8 mC/kg is ineffective. As estimated by the rate of 239Pu accumulation and by the life span shortening, the minimum effective and the maximum ineffective doses are 104.8 and 80.5 cGy and 89.2 and 79.2 cGy, respectively.     

The effective and ineffective levels of the joint action of 239Pu and gamma radiation according to the change in the ECG indices of dogs

Effective and ineffective levels of the isolated and combined action of inhaled 239Pu and external gamma radiation on dogs were estimated by some changes in the ECG. Specific share of each factor in the combined effect and the quality coefficient of 239Pu were estimated by two criteria of changes in the ECG. The data were extrapolated to man by the most reliable criterion, that is, the decrease in the ECG voltage indicated by the sum of R I, II, III waves.     

Quantitative evaluation of the effectiveness of exposure of the joints to 239Pu and tributyl phosphate by the degree of leukopenia in rats

The efficiency of the combined effect of 239Pu and tributyl phosphate was estimated by the severity of leucopenia in Wistar rats using the regression method and comparing the value of the actual change with the expected one. It was shown that the additive effect of the two agents delivered simultaneously was only exceeded when their doses were the largest that is, approximate the acute levels. With levels ranging from subacute effective to minimum effective ones the additivity diminished.     

The cytotoxic activity of natural killer cells exposed to the joint and separate actions on the body of 239Pu, hexachlorobutadiene and tributyl phosphate

Wistar rats were subjected to a single exposure to 239Pu nitrate through inhalation with the subsequent procedure of imitation of inhalation or without it (the amount of 239Pu deposited in the lungs in 24 hr was 8.9 +/- 1.9 kBq/lung) and inhalation of hexachlorobutadiene and tributyl phosphate within one month in a combination with the radionuclide or without it. There was a 1.5-fold increase, above additive, in the harmful effect of 239Pu and chemical agents on the function of natural killers as observed 15--30 days after the combined exposure as compared to individual inhalation. On days 120 to 240 cell cytotoxic activity in rats of all groups was normalized to reach or to exceed the intact control.     

Radiosensitivity and proliferative activity of vertebral CFU-S surviving in mice injected with oncogenic activities of 239Pu or 241Am

Survival, radiosensitivity and capability to produce differentiated progeny were followed in CFU-S from lumbar vertebrae of mice injected with 198.6 kBq 239Pu/kg or 208.6 kBq 241Am/kg. The CFU-S assay and 59Fe uptake into spleen colonies were used. The number of CFU-S from treated mice was significantly lower than in controls. Higher radiosensitivity of CFU-S from 239Pu- or 241Am-treated mice was demonstrated using additional exposure to 0.5 Gy X-rays 1, 24, 48, 72 hrs after cell transplantation and expressed more precisely by survival curves obtained 1 hr after the marrow cell injection. The effect of 239Pu on CFU-S was characterized by Do 0.58 Gy (n = 0.91) and that of 241Am by Do 0.64 Gy (n = 0.91); corresponding control values were Do 0.89 Gy, n = 1.11. Lower iron utilization due not only to the decreased CFU-S numbers, but also to the defective production of erythroid cells per one CFU-S was found. Complexity of radiation effect on hemopoietic stem cells was demonstrated by the present study.     

Dynamics of changes in the rat thymus gland as affected by intratracheal administration of 238Pu

A study was made of the effect of intratracheal administration of 238Pu nitrate on rat thymus. Incorporation of an acutely effective dose of the radionuclide (740 kBq X kg-1) induced damages to all thymus structures. The optimal blastomogenic 238Pu amount (92.5 kBq X kg-1) administered during the chronic period of the disease caused complex changes of atrophic, hyper- and neoplastic nature the lymphoid component of the thymus being primarily damaged.     

Frequency of structural chromosome aberrations in the hepatocytes of rats exposed to polymeric 239Pu

Intravenous injection of polymeric 239Pu(IV) nitrate (166.5, 55.5 and 18.5 kBq/kg body mass) to Wistar rats was shown to produce biphase changes in the frequency of hepatocyte chromosome aberrations. The increase in the structural damages to chromosomes at later times of observation was a pronounced function of radiation dose. The absence of such a dependence at early times was evidently due to the elimination of damaged liver parenchyma cells.     

Interpretation of cytogenetic damage induced in the germ line of male mice exposed for over 1 year to 239Pu alpha particles, fission neutrons, or 60Co gamma rays

The relative biological effectiveness (RBE) of 239Pu alpha particles, fission neutrons (0.85 MeV), and 60Co gamma rays has been evaluated for the induction of reciprocal chromosome translocations in spermatogonia and of chromosome/chromatid fragments and chromatid rearrangements in the primary spermatocyte of adult male B6CF1 mice. Age concurrency was maintained for both internal and external radiations which were delivered at about 1 rad/week for 239Pu (single intravenous dose of 10 microCi/kg), 0.67, 1.67, and 2.67 rad/week for neutrons, and 6.95, 17.4, and 32 rad/week for gamma rays for at least 60 weeks. In terms of frequency of translocations, the response to the alpha emitter was nonlinear (concave downward) with little dose-response predictability; to cumulative neutron exposures the response was linear, without evidence of a dose-rate effect; and to gamma radiation the responses were linear, and a significant dose-rate effect was seen. RBE estimates are variable. For translocations, the n/gamma ratio is between 10 and 24, depending upon weekly dose level, and the ratio is 1 or less for the alpha particle relative to the neutron. For fragments, the n/gamma ratio is 18 to 22, depending upon age factors, and alpha/n is 1.5. For chromatid rearrangements, n/gamma is 7 and alpha/n is essentially indeterminate, but much below one. The overall response to the alpha emitter is interpreted to be a complex function of (a) microdosimetric heterogeneity, (b) a nearly invariant deposition pattern in the gonad, (c) the high sensitivity of differentiating spermatogonia to cell killing, and (d) the capacity of stem cells in relatively radiation-free areas to progressively assume the major spermatogenic role.     

A comparison of the natural survival of beagle dogs injected intravenously with low levels of 239Pu, 226Ra, 228Ra, 228Th, or 90Sr

The natural survival, relative to properly chosen controls, of 26 beagle dogs injected once intravenously with an average of 0.58 +/- 0.04 kBq 239Pu/kg, 23 dogs injected with 2.31 +/- 0.43 kBq 226Ra/kg, 13 dogs injected with 1.84 +/- 0.26 kBq 228Ra/kg, 12 dogs injected with 0.56 +/- 0.030 kBq 228Th/kg, and 12 dogs injected with 21.13 +/- 1.74 kBq 90Sr/kg was evaluated statistically. The amounts of these radionuclides are related directly to the estimated maximum permissible body burdens for humans suggested in ICRP II (1959). They constitute a level of exposure that initially was assumed to cause no deleterious effects in dogs. This study had two objectives: (1) identification of homogeneous control groups against which to evaluate the survival of the irradiated groups and (2) comparison of the survival characteristics and estimation of mortality or hazard rate ratios for control dogs vs dogs injected with the baseline dosages given above. It was shown, by goodness-of-fit plots, that the Cox proportional hazards model was an appropriate method of analysis. Therefore, covariates that possibly could influence survival were tested for significance. Only the effects of grand mal seizure, which is caused in epileptic dogs by an external stimulus and can be fatal if untreated, were significant (P less than 0.0001). Consequently, in the final model, death from grand mal seizure was considered as accidental. After censoring the dogs dying from grand mal seizure, it was established that the data for the control groups from previous and contemporary experiments could be pooled. The change in hazard rates relative to controls resulting from exposure to the baseline radionuclide level was modest, 1.6 times for 239Pu (P = 0.033), 1.0(4) for 226Ra (P = 0.86), 1.9 for 228Ra (P = 0.035), 2.5 for 228Th (P less than 0.001), and 0.52 for 90Sr (P = 0.041). Bone tumor induction was clearly elevated in dogs injected with 239Pu and 228Th. When the effect of these bone tumors on survival was removed by censoring, the dogs injected with 239Pu were indistinguishable from the controls. In contrast, the effects of bone tumor on group survival of the 228Ra and 228Th dogs were not significant. Thus, no additional life-shortening effects beyond those attributable to bone tumor were suggested by these data for 239Pu, but other, as yet unspecified, confounders are suggested for 228Ra and 228Th.     

Changes in the mucous membrane of the trachea and bronchi in dogs based on bronchoscopic data for the combined action of 239Pu and gamma-radiation as compared with the individual actions

It was established that under conditions of combined exposure of dogs to external gamma- and internal alpha-radiation, a preirradiation with 51.6 mC/kg gamma-rays prevents the development of the signs of endobronchitis which are typical for endobronchitis induced by inhalation of submicron 239Pu dioxide and manifested by hyperemia of trachea and bronchus mucosa, edema, and the presence of mucopurulent exudate.     

The levels of soil pollution with plutonium isotopes in the Bryansk Oblast (following the accident at the Chernobyl Atomic Electric Power Station)]

The estimates of plutonium concentration in soils of Western regions of Bryansk (Krasnogorsky, Novozybkovsky, Zlynkovsky and Klintsovsky) are presented. The levels of soil contamination with plutonium within the regions examined vary by 4-5 times, although no definite geographical direction of pollution intensity within the territory examined is noted. The cumulative concentration of isotopes (238Pu, 239Pu, and 240Pu) varies within 21-112 Bq/kg.