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Elevated epidermal growth factor receptor binding in plutonium-induced lung tumors from dogs.

The objective of this study is to examine and characterize epidermal growth factor receptor (EGF-R) binding in inhaled plutonium-induced canine lung-tumor tissue and to compare it with that in normal canine lung tissue. Crude membrane preparations from normal and lung-tumor tissue from beagle dogs were examined in a radioreceptor assay, using 125I-labeled epidermal growth factor (EGF) as a ligand. Specific EGF receptor binding was determined in the presence of excess unlabeled EGF. We have examined EGF receptor binding in eight lung-tumor samples obtained from six dogs. Epidermal growth factor receptor binding was significantly greater in lung-tumor samples (31.38%) compared with that in normal lung tissue (3.76%). Scatchard plot analysis from the displacement assay revealed that there was no statistical difference in the binding affinity but significantly higher concentration of EGF-R sites in the lung-tumor tissue (619 fmol/mg) than in normal lung tissue (53 fmol/mg). The increase in EGF-R number in plutonium-induced dog lung tumors does not seem to correlate with increase in the initial lung burden exposure to plutonium. Our results demonstrate that there is a significant increase in EGF-R binding in inhaled plutonium-induced dog lung tumors.

Adenocarcinoma, Papillary↗

[Estimation of the levels of plutonium isotopes in soil and bed deposits during environmental radiological monitoring].

The paper deals with the development of a highly sensitive method for determining plutonium isotopes (238Pu, 239Pu + 240Pu, 242Pu) in the solid samples of environmental objects with preliminary radiochemical preparation. The chosen conditions for preparation of samples permit effective separation of plutonium from mixing alpha-radiating radionuclides and allow plutonium to release in the radiochemically pure form to a sample to be calculated. Spectrometric measurements of the calculated samples and identification of isotopes were made on a "Progress-alpha" alpha-spectrometric unit having a silicon semiconductor detector. The developed procedure is rather reliable in identifying and estimating the content of major plutonium isotopes in the soil and bed deposits at their background values (1 Bc/kg or higher). The paper presents the results of analysis of samples of the soil selected during radioecological monitoring in the South-Western Okrug of Moscow, as well as the alpha-spectra obtained.

Environmental Monitoring↗

[Clinical and functional tests for pulmonary hypertension and cor pulmonale in chronic pulmonary berylliosis and plutonium-induced pulmonary sclerosis].

Berylliosis and plutonium pneumosclerosis patients appeared to have two types of pulmonary hypertension: hypervolemic and hypertonic ones. Hypervolemic type of pulmonary circulation was revealed in 31.7% of berylliosis patients and in 53.8% of plutonium pneumosclerosis patients. Hypertonic type of pulmonary circulation was seen in 68.3% of berylliosis patients and in 46.2% of plutonium pneumosclerosis patients mainly at stages II and III. Berylliosis and plutonium pneumosclerosis patients are subjects for early pulmonary hypertension--moderate in most patients at stage I and high at stage II and III. Pulmonary hypertension is a main pathogenetic factor underlying chronic corpulmonale formation.

Adult↗

Promotion of pulmonary carcinogenesis by plutonium particle aggregation following inhalation of 239PuO2.

Promotion of lung tumor formation from inhaled 239PuO2 in rats may be associated with aggregation of plutonium particles near bronchioles. The relationship of plutonium particle aggregation in the lung and the development of lung tumors after inhalation of 239PuO2 was studied in 664 life span rats with mean lung doses ranging from 0.35 to 20 Gy. Plutonium particle concentration and aggregation were determined from autoradiographic sections of the left lung lobe. The increase in particles/cm2 and mean number of particles per aggregate up to 20 Gy were directly proportional to lung dose. Aggregates with greater than 25 particles increased linearly with dose from 0.2% at 1.4 Gy to 8.2% at 20 Gy, in a pattern similar to increasing severity of pulmonary fibrosis and incidence of lung tumors. Lung tumor incidence increased from about 6% at 1.4 Gy to 83% at 8 Gy; no further increase in lung tumors was seen at doses greater than 8 Gy. Maximum lung tumor incidence at 8 Gy corresponded to a particle concentration of 130/cm2 and four particles/aggregate with 4% of aggregates having greater than 25 particles. Aggregation of inhaled plutonium particles in clusters of greater than 25 particles resulted in daily doses of only a few centigray to focal tissue regions containing clustered particles, yet these doses appeared sufficient to cause pulmonary fibrosis and promotion of pulmonary carcinogenesis.

Administration, Inhalation↗

The relationship of bone marrow type and microvasculature to the microdistribution and local dosimetry of plutonium in the adult skeleton.

Most plutonium-induced bone tumors in beagles arise in trabecular bone sites surrounded by hematopoietic tissue. The microvasculature and the relative incorporation of 241Pu (a low energy beta emitter) on trabecular bone surfaces from red and fatty marrow sites were studied in the adult beagle. The vascular volume, as determined by India ink perfusion, was about 16% in the red marrow and about 2% in the fatty marrow. The red marrow has large vascular sinusoids with a discontinuous endothelial lining whereas fatty marrow has a closed capillary bed. Plutonium concentrations on bone surfaces of red marrow sites are about 0.43 pCi/cm2/nCi/kg of injected dosage, a factor of eight greater than at fatty marrow sites (0.053 pCi/cm2/nCi/kg). The differences in the bone marrow microvasculature between red and fatty marrow help to explain differences in plutonium incorporation and local bone physiology in these skeletal sites. These observations may relate to the nonuniform distribution of plutonium-induced osteosarcomas observed in adult, long-lived mammals.

Animals↗

The metabolism of radiohafnium in rats and hamsters: a possible analog of plutonium for metabolic studies.

The metabolism of radiohafnium (175Hf + 181Hf) was studied in male Sprague-Dawley rats and Chinese hamsters for periods of up to 168 days. The results were compared with similar data for 239Pu in the same rat strain. In rats and hamsters the radiohafnium organ distribution was skeleton greater than skin greater than muscle greater than liver at about 7 days postinjection. Retention of radiohafnium and plutonium was similar in plasma and liver, as were the retention times observed for other organs: Absorption of radiohafnium from the gastrointestinal tract of rats was less than 0.05%. Biochemical studies showed that the radiohafnium was bound mainly to the iron-transport protein, transferrin, in blood plasma and in the liver cytosol of both the rat and the hamster, as has been observed also for plutonium. The metabolic behavior of radiohafnium mimics, to a large extent, that of plutonium, and it is suggested that radiohafnium can serve as a non-alpha-particle-emitting analog of plutonium for metabolic, biochemical, and selected human investigations.

Animals↗

Age determination of plutonium material in nuclear forensics by thermal ionisation mass spectrometry.

Age is a key parameter when deducing the history of plutonium material, i.e. the plutonium produced in the nuclear reactors. This is of vital importance, when a smuggled plutonium sample has been seized and the origin has to be determined. A methodology is described which allows accurately to determine the age of plutonium material by thermal ionisation mass spectrometry using independent parent/daughter relations. This has been demonstrated for Reference Materials of known ages as well as for real samples. The already established method using gamma spectrometry is compared to this.

Journal Article↗

Analysis of plutonium in soil samples

Procedures for analysis of plutonium in soil samples were developed using anion exchange as a purification technique. Special attention was paid to removing impurities of 228Th which interferes in 238Pu determination by alpha spectrometry. Two anion-exchange methods were compared. The determination of plutonium in soil involves the conversion of soil samples to acid-soluble form. Two methods for the extraction of plutonium from a natural reference soil were compared. The first method (a direct digestion in nitric acid) is suitable for the determination of plutonium in large amounts of sample. The second method involves microwave digestion of soil (5 g) with a mixture of HNO3, HCl and HF, and is suitable for saving time in routine determinations. Activities calculated with a reference soil matrix were in good agreement with the reference value. The microwave digestion method was applied in a study of different soil samples, and recoveries ranged between 20% and 50%.

Journal Article↗

Separation of plutonium and neptunium species by capillary electrophoresis-inductively coupled plasma-mass spectrometry and application to natural groundwater samples.

Capillary electrophoresis (CE) was coupled to ICPMS in order to combine the good performance of this separation technique with the high sensitivity of the ICPMS for the analysis of plutonium and neptunium oxidation states. The combination of a fused-silica capillary with a MicroMist AR 30-I-FM02 nebulizer and a Cinnabar small-volume cyclonic spray chamber yielded the best separation results. With this setup, it was possible to separate a model element mixture containing neptunium (NpO2(+)), uranium (UO2(2+)), lanthanum (La3+), and thorium (Th4+) in 1 M acetic acid. The same conditions were also suitable for the separation of various oxidation states of plutonium and neptunium in different aqueous samples. All separations were obtained within less than 15 min. A detection limit of 50 ppb identical with 2 x 10(-7) M (3-fold standard deviation of a blank) was achieved. To prove the negligible disturbance of the plutonium and neptunium redox equilibria during the CE separations, plutonium and neptunium speciation by CE-ICPMS in acidic solutions was compared with the results of UV/visible absorption spectroscopy and was found to be in good agreement. The CE-ICPMS system was also applied to study the reduction of Pu(VI) in a humic acid-containing groundwater at different pH values.

Journal Article↗

Effect of plutonium-239 on the mitotic activity of mouse bone marrow cells.

Mitotic index of the bone marrow cells was studied in femoral bone marrow of mice given 313 kBq 239Pu kg-1. The attention was turned to the femoral midshaft and the mitosis concentration, intensified by Colcemid stathmokinetic effect, was evaluated in a sampling field from endosteal surface to the central venous canal, throughout 68 weeks. It has been found that the plutonium effect in the sampling band is rather uniform except the points in subendosteal zone early after plutonium injection, where the mitotic index was reduced in such a way that the mitotic gradient, observed in controls, was affected. The mitotic activity in femoral diaphysis of plutonium injected mice was mobilized approximately till the 30th week of contamination. Later it deteriorated progressively. The results are discussed and should not be regarded as representative for the entire bone marrow hemopoiesis.

Animals↗

Results of the international Pu-2000 exercise for plutonium isotopic composition measurements.

An international comparison for plutonium isotopic composition measurement, known as the Pu-2000 exercise, was organized by the ESARDA NDA-WG (European Safeguards Research and Development Association, Working Group on Techniques and Standards for Non-Destructive Assay). The aim of this comparison was to test X- and gamma-ray spectrometry methods over a large range of isotopic ratios. These methods are based on the complex analysis of several X- and gamma-rays in the KX region of the plutonium spectrum and also in the 120-700 keV energy range. The results obtained by the participants with their corresponding uncertainties are presented in this document and compared to the declared values. The main conclusions of the work are also given. No important bias due to an inadequate knowledge of the nuclear data for plutonium isotopes was observed.

International Cooperation↗

Treatment of accidental intakes of plutonium and americium: guidance notes.

The scientific basis for the treatment of the contamination of the human body by plutonium, americium and other actinides is reviewed. Guidance Notes are presented for the assistance of physicians and others who may be called upon to treat workers or members of the public who may become contaminated internally with inhaled plutonium nitrate, plutonium tributyl phosphate, americium nitrate or americium oxide.

Americium↗

Soil-plant transfer of plutonium and americium in contaminated regions of Belarus after the Chernobyl catastrophe.

Experimental data are presented for the soil to plant transfer of plutonium and americium into the main species of grass vegetation of Belarusian grasslands contaminated as a result of the Chernobyl catastrophe of 1986. The content of radionuclides in pore soil solutions and the total reserve of biologically available forms of plutonium and americium in rooting layers of different soil varieties have been established. The distribution coefficients of (239,240)Pu and 241Am between the solid phase and pore waters of soils have been evaluated. The migration ability and biological availability of radionuclides in soils with different structures of the absorbing complex have been analyzed for various landscape conditions. The dependence of soil to plant transfer of plutonium and americium on the content and composition of organic matter, and other characteristics of the soil complex has been studied. On the basis of these data, predictions of the contamination levels of the main grass species of natural and agricultural ecosystems by 241Am are presented.

Americium↗

Plutonium anomalies in attic dust and soils at locations surrounding the Nevada Test Site.

Attic dust and soil samples were collected during the Summer of 1996 and the Spring of 1997 in southern Nevada and southern Utah. Analysis of the samples for radiocesium and plutonium give activity ratios of radiocesium/plutonium that range from 0.7 +/- 0.1 to 27 +/- 2, well below the world-wide fallout ratio of 34 +/- 4 (as of 1 July 1997). This indicates anomalous plutonium throughout the region, including areas to the south of the Nevada Test Site (NTS), generally believed to have received only world-wide fallout. Safety tests and above-ground detonations that resulted in incomplete fission, conducted at the NTS during the 1950's and 1960's, are likely sources of this excess plutonium.

Cesium Radioisotopes↗

Effect of industrial pollution on soil-to-plant transfer of plutonium in a Boreal forest.

Plutonium in a forest ecosystem was studied at different distances from the copper and nickel smelter at Monchegorsk, Kola Peninsula, Russia. Soil and plant samples were collected 7 (site A), 16 (B), 21 (C) and 28 (D) km from the smelter and at a reference site situated in Finland, 152 km from Monchegorsk. The deposition of Cu in litter and in the organic layer decreased from 10700 mg/m2 at site A to 33 mg/m2 at the reference site, the deposition of Ni from 14300 to 29 mg/m2. From the reference site to site A, the volume of the litter layer increased almost five-fold. Most of the 239,241Pu in soil was found in the organic layer and in the litter layer. When industrial pollution increased, the content of 239,240Pu in the litter layer increased (from approx. 0.5 at site D to 15 Bq/m2 at site A) whereas, that in the organic layer decreased (from approx. 20 at site D to 5 Bq/m2 at site A). Four different plant species typical for the subarctic environment were collected at each sampling site: Deschampsia flexuosa (forest hair grass); Empetrum nigrum (crowberry); Vaccinium myrtillus (blueberry); and Vaccinium citis idaea (lingonberry). The concentration of 239,241Pu increased with pollution in Deschampsia flexuosa (from approx. 2 at site D to 7 mBq/kg at site A), Empetrum nigrum (from approx. 3 at site D to 14 mBq/kg at site A) and Vaccinium myrtillus (from approx. 1 at site D to 8 mBq/kg at site A). In Vaccinium vitis idaea, the Pu concentration did not have any clear trend of association with pollution. With the exception of Vaccinium vitis idaea, the aggregated transfer factors of plutonium (m2/kg) for the plants studied increased almost ten-fold from site D to site A, the range being 3 x 10(-5)-3 x 10(-4) m2/kg for Deschampsia flexuosa, 7 x 10(-5)-5 x 10(-4) m2/kg for Empetrum nigrum and 3 x 10(-5)-3 x 10(-4) m2/kg for Vaccinium myrtillus. The most likely explanation for the higher transfer factors of plutonium near the smelter is contamination of the plants by litter rather than root uptake.

Biological Availability↗

Vertical and horizontal fluxes of plutonium and americium in the western Mediterranean and the Strait of Gibraltar.

New data on the vertical distributions of plutonium and americium in the waters of the western Mediterranean and the Strait of Gibraltar are examined in terms of the processes governing their delivery to, transport in and removal from the water column within the basin. Residence times for plutonium and americium in surface waters of approximately 15 and approximately 3 years, respectively, are deduced, and it is shown that by the mid 1990s only approximately 35% of the 239,240Pu and approximately 5% of the 241Am deposited as weapons fallout still resided in the water column. Present 239,240Pu inventories in the water column and the underlying sediments are estimated to be approximately 25 TBq and approximately 40 TBq, respectively, which reconcile well with the time-integrated fallout deposition in this zone, taken to be approximately 69 TBq. The data show that there are significant net outward fluxes of plutonium and americium from the basin through the Strait of Gibraltar at the present time. These appear to be compensated by net inward fluxes of similar magnitude through the Strait of Sicily. Thus, the time-integrated fallout deposition in the western basin can be accounted for satisfactorily in terms of present water column and sediment inventories. Enhanced scavenging on the continental shelves, as evidenced by the appreciably higher transuranic concentrations in shelf sediments, supports this contention.

Americium↗

Plutonium concentrations in waters from the southern Baltic Sea and their distribution in cod (Gadus morhua) skin and gills.

The concentrations of (238)Pu and (239+240)Pu in water samples and suspended particulate fractions, as well as in colloidal fraction from the southern Baltic Sea are presented. The (239+240)Pu concentration in surface seawater samples fall within range from 5.2 mBq.m(-3) for Gdańsk Bay to 150 mBq.m(-3) for Pomeranian Bay, most of which (from 52 to 96%) constituted filterable forms (</=0.45 microm). Also the distribution of plutonium in parts of cod gills and skin are presented and discussed. Over 60% of the plutonium in cod gills is accumulated in the gill arch, which suggests its metabolic origin. Most of plutonium associated with skin is in mucus, which suggests its adsorption from water.

Animals↗

Uptake and translocation of plutonium in two plant species using hydroponics.

This study presents determinations of the uptake and translocation of Pu in Indian mustard (Brassica juncea) and sunflower (Helianthus annuus) from Pu contaminated solution media. The initial activity levels of Pu were 18.50 and 37.00 Bq ml(-1), for Pu-nitrate [239Pu(NO3)4] and for Pu-citrate [239Pu(C6H5O7)+] in nutrient solution. Plutonium-diethylenetriaminepentaacetic acid (DTPA: [239Pu-C14H23O10N3] solution was prepared by adding 0, 5, 10, and 50 microg of DTPA ml(-1) with 239Pu(NO3)4 in nutrient solution. Concentration ratios (CR, Pu concentration in dry plant material/Pu concentration in nutrient solution) and transport indices (Tl, Pu content in the shoot/Pu content in the whole plant) were calculated to evaluate Pu uptake and translocation. All experiments were conducted in hydroponic solution in an environmental growth chamber. Plutonium concentration in the plant tissue was increased with increased Pu contamination. Plant tissue Pu concentration for Pu-nitrate and Pu-citrate application was not correlated and may be dependent on plant species. For plants receiving Pu-DTPA, the Pu concentration was increased in the shoots but decreased in the roots resulting in a negative correlation between the Pu concentrations in the plant shoots and roots. The Pu concentration in shoots of Indian mustard was increased for application rates up to 10 microg DTPA ml(-1) and up to 5 microg DTPA ml(-1) for sunflower. Similar trends were observed for the CR of plants compared to the Pu concentration in the shoots and roots, whereas the Tl was increased with increasing DTPA concentration. Plutonium in shoots of Indian mustard was up to 10 times higher than that in shoots of sunflower. The Pu concentration in the apparent free space (AFS) of plant root tissue of sunflower was more affected by concentration of DTPA than that of Indian mustard.

Brassica↗