Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Curium”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1979

The mobility of curium-244 dioxide in the bronchially intubated rat.

The mobility of curium dioxide in the rat after pulmonary intubation has been investigated by administering suspensions containing different particle size ranges of the oxide. A major factor influencing the movement of curium from lungs to blood is the formation of hydroxide or hydrous oxide particles about 0.001 micrometer in diameter. This process is sufficiently rapid for the lung clearance kinetics of the dioxide to resemble those of a soluble compound more closely than those of an insoluble one. Filtration of 0.001 micrometer particles through the kidneys results in considerably enhanced excretion of curium relative to administered curium citrate. It is concluded that current metabolic models, which assume that solubility in the lung is a prerequisite for transport in body fluids, do not adequately describe the behaviour of curium fromthe standpoint of radiological protection.

Animals↗
PubMed1992

In vitro dissolution of curium oxide using a phagolysosomal simulant solvent system.

Detailed study of actinide oxide behavior in alveolar macrophages (AM) in vitro is limited because of the short life span of these cells in culture. We created an in vitro dissolution system that could mimic the acidic phagolysosomal environment for the actinide and be maintained for an indefinite period so that dissolution of more insoluble materials could be measured. The dissolution system for this investigation, consisting of nine different solutions of HCl and the chelating agent diethylenetriamine pentaacetate (DTPA) in distilled water, is called the phagolysosomal simulant solvent (PSS). In this system, both the pH and the amount of DTPA were varied. We could observe the effect of altering pH within a range of 4.0-6.0 (similar to that of the phagolysosome) and the effect of the molar ratio of DTPA to curium at 1000:1, 100:1, or 10:1. We chose curium sequioxide (244Cm2O3) to validate the PSS for actinide dissolution versus that occurring in AM in vitro because it dissolves significantly in less than 1 week. The polydisperse 244Cm2O3) aerosol was generated, collected on filters, resuspended, and added to the PSS solutions and to cultured canine AM. By comparing dissolution in the two systems directly, we hoped to arrive at an optimum PSS for future dissolution studies. PSS and cell culture samples were taken daily for 7 days after exposure and tested for the solubilized curium. The amount of soluble material was determined by ultracentrifugation to separate the insoluble Cm2O3 from the soluble curium in the PSS solutions and filtration for the cell-containing material.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Curium excretion studies in man and baboon: a predictive animal model.

A major rationale for performing metabolic research in laboratory animals is to obtain useful information which is applicable to man. Since it is usually impossible to determine many of the kinetic parameters which are responsible for the fate of a contaminant in inadvertently-exposed individuals, it is essential that well-controlled laboratory experimentation in animals be performed. In the present case, we will demonstrate how our experimental protocol, i.e. curium in the adult baboon, can provide a model from which to derive important characteristics of curium in man. To accomplish this goal, we have compared the retention and excretion patterns of curium in several men accidentally exposed via inhalation, burns, or puncture wounds with that of 243,244Cm citrate injected i.v. in nine adult baboons. Although many of the exposure conditions are different in considering the two primate species (human and non-human), biokinetic research in the baboon may serve to estimate tissue burdens and dose commitments in man. Comparison of the excretion rates of the nuclide in the urine of man and the baboon gives similar half times between days 10 and 50 post exposure.

Animals↗
PubMed1980

The reactions of l nm particles of plutonium-238 dioxide and curium-244 dioxide with lung fluid.

The reactions of 1 nm particles of plutonium-238 dioxide and curium-244 dioxide with rat lung fluid have been studied both in vitro and in vivo. The plutonium-238 particles are positively charged and combine by electrostatic attraction with the negative pulmonary surfactant which mediates the transfer of radioactivity to the blood. In contrast the curium-244 particles are negative and are assumed to diffuse passively through the alveolar walls. The results emphasise that electrostatic charge is an important factor governing the reaction of 1 nm actinide oxide particles with macromolecules.

Actinoid Series Elements↗
PubMed1978

The movement of plutonium, americium, and curium through the food chain.

The actinides, plutonium, americium and curium, are being produced in increasing quantites as the nuclear programme is expanded. As these alpha-particle-emitting elements are hazardous to man there is considerable concern about the movement of these elements through the environment; The uptake of these elements from soil into the plants is low, as is the gastrointestinal concentration factor. Although there are complexing agents in the environment which have been shown to complex these elements there is no evidence that these complexing agents might bring about a concentration of actinides in the food chain of man.

Actinoid Series Elements↗
PubMed1980

The wound clearance and distribution of plutonium, americium and curium in rodents.

Wound contamination was simulated by the intramuscular injections of either 239Pu, 241Am or 244Cm nitrate in the hamster and by the subcutaneous injection of either 239Pu or 241Am nitrate in the rat. The actinides moved from the hamster muscle at approximately the same rate after injection of 370 Bq of each radionuclide (approximate 80 per cent cleared after 6 months). Similarly, the rates of translocation of 239Pu and 241Am in the rat were the same after injection of 370 Bq of each radionuclide (approximate 80 per cent cleared after 1 month). The clearance of 239Pu in the rat was slower after injection of 14.8 kBq and more rapid after injection of 20 Bq (approximately 40 per cent and 90 per cent moved after 1 month, respectively) while the movement of 241Am showed no dependence on the administered dose over the same range. The mixing of 239Pu and 241Am prior to intramuscular injection appeared to enhance the clearance of both radionuclides. The levels of accumulation of each actinide in the skeleton and liver of both species showed that they reached the circulation predominantly in soluble form. Some uptake of Pu and Am in regional lymph nodes was also observed, indicating that lymphatic clearance of polymeric material also took place.

Americium↗
PubMed1991

Gastrointestinal absorption of neptunium and curium in humans.

The gastrointestinal absorption of Np and Cm has been determined in five male adult volunteers. The Np and Cm, which were in citrate solution, were taken with food. An initial experiment with each individual determined the fraction of each element excreted in the urine following intravenous administration. Subsequently, the results for urinary excretion for the two routes of administration were used to calculate the fractional absorption (f1) of ingested Np and Cm. The mean f1 values were: Np (2.0 +/- 0.2) X 10(-4), range (1.2-2.9) X 10(-4), and Cm (1.7 +/- 0.3) X 10(-4), range (0.95-3.0) X 10(-4), the quoted uncertainties being the standard error of the means. Currently, the International Commission on Radiological Protection recommends a value of 10(-3) for both elements. Cumulative urinary excretion over 1 wk after intravenous injection accounted for about 20%-40% of administered Np and 7%-10% of Cm. At the conclusion of the experiment, the total committed effective dose equivalent for each volunteer was calculated to be in the range 130-250 microSv, based on the individual f1 values, and, in some cases, a knowledge of the rate of clearance of 239Np through the gut as measured by whole-body counting.

Adult↗