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PubMed1992

Alveolar macrophage kinetics after inhalation of 239PuO2 by CBA/Ca mice: changes in synthesis of DNA.

For workers in the nuclear industry, the primary route for the entry of radioactive materials into the body is by inhalation, and the rate of clearance of particles from the pulmonary region of the lung is an important factor in determining radiation dose. It is the function of alveolar macrophages (AM) to maintain the sterility of the lung and to remove insoluble particles from the respiratory surfaces and airways. The AM population is not static, and under normal conditions the loss of macrophages from the alveoli via the conducting airways is balanced by renewal. Studies of the effects of external irradiation on the kinetics of AM are numerous, but to date little is known about the effects of inhaled radioactive particles. In this investigation the effects of inhaled 239PuO2 (plutonium dioxide) particles on the synthesis of DNA by AM were studied at times up to 77 days after exposure. We also measured the number of cells recovered by bronchoalveolar lavage and the incidence of AM with nuclear aberrations. The latter provides a sensitive indicator of the effects of radiation. One of the earliest effects observed after exposure to 239PuO2 is a reduction in the number of AM recovered by lavage. This reduction is associated with a 3-fold reduction in the proportion of AM undergoing DNA synthesis at early times after exposure. The overall mean pulse labeling index of AM recovered from sham-exposed mice is 1.68%, and no trend is observed with time.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1976

[Isotop cardiac pacemaker during pregnancy. 3 cases].

The authors report three cases of full term pregnancies, without complications, in women with isotopic pacemakers. The newborn infants were normal. In one case, pregnancy occurred in a patient who already had a pacemaker. In two cases, the pacemaker was inserted during pregnancy (at 1 and 1/2 and 5 months respectively), in the treatment of syncopal attacks due to paroxysmal atrioventricular block. This type of pacemaker using a radioactive source (Plutonium 238) is, by virtue of the low degree of radiation, harmless and may be used in women of childbearing age. Under the least favourable conditions (pacemaker box in abdominal situation), the dose delivered during pregnancy (57 mrem) is approximately 20 times less than the authorised dose (1125 mrem).

Abdomen↗
PubMed1975

[Experimental x-ray diagnosis of osteosarcoma].

While using different methods of skeletal investigation, definite alterations were revealed in frequency of osteosarcomas under plutonium exposure (2.5 muC/Kg). The ratio of the corresponding values is 1:1,2:1,27:1,47. The highest incidence of osteosarcomas was noted in the complex roentgeno-morphological study (according to an extensive scheme of procurement of the osteomaterial) -- 39.8% In separate application of different methods of skeletal investigation the roentgenological method seems to be prefered: it determines more precisely the number of tumor nodes and the number of tumor-bearing rats, accordingly.

Animals↗
PubMedDate not supplied

[Comparative characteristics of environmental factors of rural localities in the area of Totsk nuclear explosion].

Environmental pollution of rural settlements in the vicinity of Totsk nuclear explosion was investigated. The findings show that the blanket of snow, soil and drinking water in the polluted area did not differ from those in the control district. High levels of stable strontium in the soil and drinking water and those of iodine in the water were detected. The concentrations of plutonium-239, 240 and cesium-137 in the soil were higher than the levels of global sediments and the baseline values of cesium-137 for the Orenburg Region.

Cesium Radioisotopes↗
PubMed1997

Molecular alteration of alpha-induced transformed Syrian hamster embryo cells.

Syrian hamster embryo (SHE) cells are irradiated by alpha particles emitted from Plutonium-238 in vitro. Transfection frequencies of donor DNA derived from passaged cells, including monocloned cells from 20th passage cells, after irradiation are parallel with their tumorigenicity of donor cells. After transformation, expressions of H-ras and c-myc genes are in the state of activation, which might be resulted from occurrence of mutation in H-ras gene and hypomethylation of c-myc gene respectively, even though no alteration was observed on their restriction fragment length polymorphisms (RELP) patterns of both genes. On the other hand, expression of p53 gene is also found to be in the state of activation in transformant, but no heavy staining of p53 protein appeared in the transformant-derived tumor with p53 specific McAb HD 200. This might be result from the partial deletion of p53 cDNA in transformant by reverse transcriptional polymerase chain reaction (RT-PCR). These results imply that activation of H-ras and c-myc genes coupled with inactivation of p53 tumor suppressor gene play important role in alpha particle-induced cell transformation.

Alpha Particles↗
PubMedDate not supplied

[Accumulation of industrial radionuclides by the Yenisei River aquatic plants in the area affected by the activity of the mining and chemical plant].

The aim of the paper is to investigate accumulation of artificial radionuclides by the Yenisei River aquatic plants collected in the area affected by the activity of the Mining-and-Chemical Combine (Zheleznogorsk) from 1997 to 2000. The samples of aquatic plants were of four species: Potamogeton lucens, Fontinalis antipyretica, Elodea canadensis, and Ceratophyllum demersum. The gamma-spectrometric analysis of the samples of aquatic plants for artificial radionuclides revealed a wide spectrum of long-half-life and short-half-life radionuclides. Radionuclides of activation origin were found in the aquatic plants taken both near the Combine and 200 km down of it. The data obtained suggest that the cooling water of the operating reactor is still being released into the Yenisei. The radiochemical analysis of aquatic plants revealed strontium and plutonium isotopes. Among the aquatic plants, the highest concentration factors for the principal radionuclides were recorded in Fontinalis antipyretica (water moss).

Chemical Industry↗
PubMedDate not supplied

[Radiation hazard in the use of radioisotopic neutralizers of static electricity].

Spectrometry was used by means of an alpha-radiometer on a [symbol: see text]porpecc-[symbol: see text] hard-and-software complex to study the radioactive contamination of the surfaces of neutralizers with plutonium 239-based ionizing radiation sources, which are employed to remove electrical charges from electrifiable materials. While using the neutralizers, the operating personnel is shown to be exposed to radiation. The level of removed radioactive contamination during half-a-year exploitation of the neutralizers was greater than the maximum allowable values on the average by several times. Radiation hazard in the use of radioisotopic neutralizers of static electricity is outlined.

Environmental Monitoring↗
PubMedDate not supplied

[Cytogenetic effects of alpha-irradiation due to incorporated 239Pu].

Intravenous injection of plutonium dioxide with 1-2 microns particle sizes in amount of 92.5, 46.3 and 23.2 kBq/kg of body mass increased the yield of chromosome aberrations in bone marrow cells of rats by 3.7, 2.3 and 1.7 times, correspondingly, in comparison with the spontaneous level. The model of chromosome aberration dependence on dose of radionuclide was developed based on the experimental results.

Animals↗
PubMed2003

Quantitative comparisons of cancer induction in humans by internally deposited radionuclides and external radiation.

PURPOSE: To compare quantitative estimates of lifetime cancer risk in humans for exposures to internally deposited radionuclides and external radiation. To assess the possibility that risks from radionuclide exposures may be underestimated. MATERIALS AND METHODS: Risk estimates following internal exposures can be made for a small number of alpha-particle-emitting nuclides. (1) Lung cancer in underground miners exposed by inhalation to radon-222 gas and its short-lived progeny. Studies of residential (222)Rn exposure are generally consistent with predictions from the miner studies. (2) Liver cancer and leukaemia in patients given intravascular injections of Thorotrast, a thorium-232 oxide preparation that concentrates in liver, spleen and bone marrow. (3) Bone cancer in patients given injections of radium-224, and in workers exposed occupationally to (226)Ra and (228)Ra, mainly by ingestion. (4) Lung cancer in Mayak workers exposed to plutonium-239, mainly by inhalation. Liver and bone cancers were also seen, but the dosimetry is not yet sufficiently good enough to provide quantitative estimates of risks. Comparisons can be made between risk estimates for radiation-induced cancer derived for radionuclide exposure and those derived for the A-bomb survivors, exposed mainly to low-LET (linear energy transfer) external radiation. Data from animal studies, using dogs and rodents, allow comparisons of cancer induction by a range of alpha- and beta-/gamma-emitting radionuclides. They provide information on relative biological effectiveness (RBE), dose-response relationships, dose-rate effects and the location of target cells for different malignancies. RESULTS: For lung and liver cancer, the estimated values of risk per Sv for internal exposure, assuming an RBE for alpha-particles of 20, are reasonably consistent with estimates for external exposure to low-LET radiation. This also applies to bone cancer when risk is calculated on the basis of average bone dose, but consideration of dose to target cells on bone surfaces suggests a low RBE for alpha-particles. Similarly, for leukaemia, the comparison of risks from alpha-irradiation ((232)Th and progeny) and external radiation suggest a low alpha RBE; this conclusion is supported by animal data. Risk estimates for internal exposure are dependent on the assumptions made in calculating dose. Account is taken of the distribution of radionuclides within tissues and the distribution of target cells for cancer induction. For the lungs and liver, the available human and animal data provide support for current assumptions. However, for bone cancer and leukaemia, it may be that changes are required. Bone cancer risk may be best assessed by calculating dose to a 50 micro m layer of marrow adjacent to endosteal (inner) bone surfaces rather than to a single 10 micro m cell layer as currently assumed. Target cells for leukaemia may be concentrated towards the centre of marrow cavities so that the risk of leukaemia from bone-seeking radionuclides, particularly alpha emitters, may be overestimated by the current assumption of uniform distribution of target cells throughout red bone marrow. CONCLUSIONS: The lifetime risk estimates considered here for exposure to internally deposited radionuclides and to external radiation are subject to uncertainties, arising from the dosimetric assumptions made, from the quality of cancer incidence and mortality data and from aspects of risk modelling; including variations in baseline rates between populations for some cancer types. Bearing in mind such uncertainties, comparisons of risk estimates for internal emitters and external radiation show good agreement for lung and liver cancers. For leukaemia, the available data suggest that the assumption of an alpha-particle RBE of 20 can result in overestimates of risk. For bone cancer, it also appears that current assumptions will overestimate risks from alpha-particle-emitting nuclides, particularly at low doses.

Animals↗
PubMed1992

Induction of sister chromatid exchanges by extremely low doses of alpha-particles.

The induction of sister chromatid exchanges (SCE) was examined in Chinese hamster ovary cells irradiated in the G1 phase of the cell cycle with alpha-particles from a plutonium-238 source. A significant increase in the frequency of SCE occurred with doses as low as 0.31 mGy (31 millirads). Although 30% of the cells showed an increased frequency of SCE at this dose, less than 1% of cell nuclei were actually traversed by an alpha-particle. A dose of approximately 2.0 Gy was necessary to produce a similar increase in SCE by X-rays. These results indicate that genetic damage may be induced by low doses of alpha-radiation in cell nuclei not actually traversed by an alpha-particle. This phenomenon may have important implications in the estimation of risks of such exposures.

Alpha Particles↗
PubMed1992

Influence of dose rate on survival time for 239PuO2-induced radiation pneumonitis or pulmonary fibrosis in dogs.

Beagle dogs were exposed once or repeatedly to 0.75-microns-diameter monodisperse aerosols of 239PuO2 by pernasal inhalation. The dogs that were exposed once received alveolar depositions (+/- standard deviation) of 3.9 +/- 1.9 kBq/kg body mass and accumulated doses of 23 +/- 8 Gy to the lung before death at 5.4 +/- 1.7 years after exposure. Dogs exposed repeatedly received a total alveolar deposition of 5.3 +/- 0.9 kBq/kg body mass during 7 to 10 semiannual exposures and accumulated doses of 22 +/- 5 Gy to the lung before death at 4.9 +/- 0.7 years after first exposure. Clearance of the plutonium from the lung in the dogs exposed repeatedly was slower than in the dogs exposed once. All dogs in the repeated-exposure study and all but one dog in the single-exposure study died from radiation effects. Pulmonary fibrosis accounted for 72% of the radiation-related deaths in the single-exposure study and 87% in the repeated-exposure study. The remaining dogs died with pulmonary cancer. Based on total cumulative radiation dose, the times after exposure to death from radiation pneumonitis and pulmonary fibrosis were not significantly different for single and repeated exposures. Thus dose rate does not appear to be an important factor in predicting death from radiation pneumonitis or pulmonary fibrosis for dogs inhaling 239PuO2.

Administration, Inhalation↗
PubMed1990

Hemoblastoses in mice contaminated with low activities of 239Pu.

Female ICR mice were injected intravenously with low activities of 239Pu (3.0 kBq, 6.0 kBq, 12.3 kBq/kg). In these mice with high spontaneous incidence of hemoblastoses the occurrence of myeloid leukemia, lymphocytic leukemia, lymphosarcoma, reticulum-cell sarcomas and osteosarcoma was studied. Hemoblastoses, on the whole, remained in their numbers radiation-independent, nevertheless, the distribution into specific types changed, with moderate prevalence of myeloid and lymphocytic leukemia and lymphosarcoma. After plutonium injection the mean survival time of mice bearing myeloid and lymphocytic neoplasias was significantly shorter than the survival of mice that died of retothelosarcoma and from other causes. These contamination-dependent differences could not be observed in matched controls. As expected, 239Pu activities used in this experiment induced osteosarcomas. Whereas in leukemogenesis alpha-radiation appeared as a factor promoting and modifying the leukemogenic process, in osteosarcoma the alpha-particles acted rather as an initiator, the effect of which was dependent on the dose to the endosteal progenitor cells.

Animals↗
PubMed1990

[Therapeutic consequences of contamination injuries by highly radioactive substances].

A case of plutonium injury of the left hand is used to explain the correct management. In addition to radical surgical excision under repeated monitoring of radioactivity, it is obligatory to commence parenteral chelation therapy with DTPA. Close cooperation with radiological technologists is necessary. Discharges and used bandages have to be analysed for their radioactive content before elimination as radioactive waste. Isolation of the patient is not required. The relevant government department has to be contacted. A health center for radiation victims with special measuring equipment is desirable.

Accidents, Occupational↗
PubMed1989

Carcinogenic effects in rat progeny exposed perinatally to radionuclides.

The distribution of two transuranic elements, plutonium and americium, in pregnant rats and in their fetuses, and the carcinogenic effects seen in progeny exposed perinatally are discussed. The appearance of malignant tumours in the liver and skeleton corresponds to the pattern of deposition of these radionuclides in the body.

Americium↗
PubMed1988

[Biological action of 239Pu during intake by inhalation and complexon therapy with Zn or Ca DTPA under experimental conditions].

The authors described the effect of substantial amounts of plutonium nitrate administered to rats by inhalation in the presence of Zn- or CaDTPA-complexon therapy for 2 months. A 2-fold decrease of absorbed doses in the lung, a 3-fold decrease in the skeleton and a 4-fold decrease in the liver were shown. The mean life of the treated animals was considerably raised. A significant reduction of the frequency of development of severe pneumosclerosis and an increase in the frequency of lung tumor development were noted. In view of the above, complexon therapy should be necessarily recommended during inhalation of radionuclides in substantial amounts.

Administration, Inhalation↗
PubMed1988

[Evaluation of genetic consequences of 238Pu incorporation into mammals].

The genetic effects of gonadal burdens of 238Pu after single injection were studied in male mice. The activity of plutonium was 7 to 1850 Bk/g. The average doses of accumulated alpha-particles in testis varied from 2 to 96 Gy.10(-2), the dose rate being 0.004 to 1 Gy.10(-2) per day. The genetic end points are: the dominant lethal mutation rate; the frequency of reciprocal translocations; the recessive lethal mutation rate and frequency of abnormal sperm head morphology. For all tests used, no linear dependence of the effect on the alpha-dose was observed. The RBE value of alpha-irradiation was 10-20 relative to chronic gamma-irradiation.

Alpha Particles↗
PubMedDate not supplied

[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.

Absorption↗
PubMed1987

Spatial distribution of disease: three case studies.

Maps transformed so as to have constant density of residential population were used to analyze the spatial distribution of disease in three specific areas. Each area had received recent attention because of suspected environmental pollution. The area adjacent to the Rocky Flats Facility (CO) was examined to identify any association between possible plutonium releases and increases in lung cancer or leukemia incidence. The industrial area of northern Contra Costa County (CA) was studied to explore a relationship between petrochemical industrial emissions and histologic-specific lung cancers. Finally, a suspected increase in the risk of congenital cardiac defects possibly related to pollution of the Santa Clara County (CA) water supply was investigated. No evidence of elevated risk of disease was found to be associated with either the Rocky Flats Facility or the polluted water of Santa Clara County. An increase in lung cancer, found by other investigators in earlier years, was shown to persist in association with industrial emissions in Contra Costa County.

Adult↗