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Biomedical subjects

B B Boecker

Publications and source records attributed to B B Boecker.

At least 55 records · Page 3Linked to original sources
PubMed1975

Prevention of radiation pneumonitis from inhaled cerium-144 by lung lavage in beagle dogs.

This study was performed to evaluate bronchopulmonary lavage and chelation therapy as a treatment method to prevent the development of radiation pneumonitis after inhalation of a radioactive aerosol. Twelve beagle dogs were exposed to an aerosol of cerium-144 in fused clay particles resulting in initial lung burdens from 47 to 64 muCi of 144-Ce per kg of body weight. Eight of the dogs were treated with a series of 10 bronchopulmonary lavages and 10 intravenous injections of calcium diethylenetriamine pentaacetate acid during the first 56 days after exposure to remove the deposited 144-Ce; the remaing 4 exposed dogs receiged no treatment. An additional 4 dogs were exposed to stable cerium and were given the course of treatment as an additional control group. Three of the 4 untreated dogs and 2 of the 8 treated dogs died 171 to 246 days after exposure with radiation pneumonitis or pulmonary fibrosis, or both. All but one of the remaining dogs were alive and apparently in good clincial health 550 dyas after exposure; the one dog had radiographic indications of pulmonary fibrosis by 365 days after exposure. The relative distribution of 144-Ce in the lungs and other major organs was similar in the treated and untreated dogs that died.

Aerosols↗
PubMed1975

Occurrence of hemangiosarcomas in beagles with internally deposited radionuclides.

In a series of related experiments to evaluate the relative toxicity of inhaled radionuclides, beagles were exposed to aerosols containing relatively soluble (chloride) or relatively insoluble (fused clay) forms of 144-Ce and 90Sr. With the solubled 144-CeCl3, significant radiation doses were delivered to the lungs, liver, and skeleton whereas, after 90-SrCl2 exposure, the radiation dose was delivered predominantly to the skeleton. In dogs exposed to 144-Ce and 90-Sr in fused clay particles, radiation doses were delivered mostly to the lungs and tracheobronchial lymph nodes. In most dogs dying within 2 years after exposure, deaths were attributable to nonneoplastic radiation-induced lesions in the target organ systems. At later times after exposure, neoplasms were the major cause of death, again occurring mostly in target organs or the adjacent tissues. Lung liver, and bone-related neoplasms, including five hepatic hemangiosarcomas, developed after 144-CeCl3 exposure. Among the bone-related sarcomas seen in dogs exposed to 144-CeC3 or 90-SrC2, the incidence of hemangiosarcomas was over 40%. Among the 20 dogs dying with pulmonary neoplasms after exposure to 144-Ce or 90Sr in fused clay particles, all had hemangiosarcomas and several also had other neoplasms. This high after exposure and differs from results in other laboratories where beagles have been exposed to both alpha and beta-emitting radionuclides.

Aerosols↗
PubMed1975

Accumulation and retention of 137Cs-labelled fused aluminosilicate particles by beagle dogs after repeated inhalation exposures.

A group of 12 beagle dogs was given weekly, individual, 10-min inhalation exposures to aerosols of 137Cs-labelled, fused aluminosilicate particles (AMAD approximately equal to 1.8 micron, sigmag approximately equal to 1.6). Whole-body counting was used to assess the pulmonary deposition associated with each exposure and the long-term retention after exposures. Groups of four dogs were removed from further exposures at the end of 10, 20 and 40 exposures, respectively. Two dogs in each group were sacrificed and the other two maintained for long-term retention measurements. The inhaled material was relatively insoluble in body fluids. In each of the sacrificed dogs, approximately equal to 96% of the body burden was in the lung and approximately equal to 1% in the tracheobronchial lymph nodes. The average pulmonary deposition was approximately equal to 20% of the inhaled aerosol for 10, 20 or 30 exposures, a value which was in agreement with previously reported single exposure data. Lower values observed for exposures 31 to 40 were apparently related to differences in respiratory patterns. The long-term, whole-body retentions appear to have effective half-lives ranging from 1200-1800 days in contrast to approximately equal to 400 days seen in singly exposed dogs. Possible reasons are discussed.

Aerosols↗
PubMed1975

Comparative pulmonary carcinogenicity of inhaled beta-emitting radionuclides in beagle dogs.

Beta-emitting radionuclides are important constituents of isotope inventories in light water reactors and may pose an inhalation hazard to industrial workers or the general population if they are released. To study the biological effects of such potential exposures, a series of life span studies was initiated in which beagle dogs were exposed to aerosols of relatively insoluble fused clay particles containing 90Y, 91Y, 144Ce or 90Sr. Groups of dogs exposed to each radionuclide received graded initial lung burdens of radioactivity. When combined with the varied physical half-lives of the four radionuclides, this resulted in a wide variety of radiation doses and dose patterns to the lung. Deaths (greater than 640 days after exposure) were generally associated with pulmonary neoplasia in dogs that inhaled 91Y, 144Ce or 90Sr. These dogs had cumulative lung doses to death greater than 20 000 rads. Exposure to 144Ce or 90Sr with dose rates that decreased slowly induced pulmonary haemangiosarcomas. Pulmonary irradiation from 91Y, with a rapidly decreasing dose rate, resulted in pulmonary epithelial tumours. No malignant lung tumours have been seen within 1540 days after exposure to 90Y. The animals in the main studies have been observed for 1342 to 2756 days after exposure.

Adenocarcinoma, Bronchiolo-Alveolar↗