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Biomedical subjects

C L Sanders

Publications and source records attributed to C L Sanders.

At least 37 records · Page 2Linked to original sources
PubMed1985

Lung clearance, translocation, and acute toxicity of arsenic, beryllium, cadmium, cobalt, lead, selenium, vanadium, and ytterbium oxides following deposition in rat lung.

Young adult rats were exposed via inhalation or intratracheal instillation to oxides of arsenic, beryllium, cadmium, cobalt, lead, selenium, vanadium, and ytterbium. Serial necropsies were performed to assess the metal content in organs at times up to several weeks after exposure. The lung clearance varied widely for these compounds, and the times to remove 50% of the initial burden ranged from 18 min for vanadium to 400 days for beryllium. Arsenic, cadmium, lead, selenium, and vanadium were initially soluble in lung, but a small fraction (1-20%) remained there over the long term. Extrapulmonary tissues often accumulated substantial amounts of the soluble oxides, and whole-body retention was often greater for compounds that were more soluble in lung. Arsenic, selenium, and vanadium translocated to carcass and bone. Arsenic, cadmium, lead, and selenium accumulated in the liver, and the kidney retained cadmium and lead. Beryllium, cobalt and ytterbium did not deposit at any extrapulmonary site in significant amounts. In general, the aqueous solubility of these compounds was a poor predictor for behavior in vivo because of their interaction with metabolic processes. Of the metal oxides tested for acute lethality following pulmonary deposition, cadmium was most toxic, followed by selenium, vanadium, and arsenic.

Animals↗
PubMed1984

Carcinogenicity of single and multiple intratracheal instillations of cadmium oxide in the rat.

The carcinogenic effects of single or multiple exposures to intratracheally instilled cadmium oxide, resulting in total doses of 0, 25, 50, and 75 micrograms, were studied in groups of 41 to 48 male Fischer rats. Pulmonary-deposited cadmium oxide did not result in increased numbers of tumors, except in the mammary gland or in rats that had three or more tumor types. Cadmium oxide was not carcinogenic in the lung, liver, kidney, or prostate gland of rats.

Animals↗
PubMed1984

Percutaneous absorption of [7.10-14C]benzo[a]pyrene and [7,12-14C]dimethylbenz[a]anthracene in mice.

The percutaneous penetration, tissue distribution, and excretion of 14C-labeled benzo[a]pyrene (BaP) and dimethylbenz[a]anthracene (DMBA) were studied in mice. Both BaP and DMBA rapidly penetrated the skin and were excreted more in the feces than in the urine. The proportion of BaP or DMBA absorbed was less with increasing applied dose due to apparent saturation of the uptake process. Uptake from the dorsal skin of the nose was similar to uptake from the dorsal nuchal skin.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1984

Radionuclide injury to the lung.

Radionuclide injury to the lung has been studied in rats, hamsters, dogs, mice and baboons. Exposure of the lung to high dose levels of radionuclides produces a spectrum of progressively more severe functional and morphological changes, ranging from radiation pneumonitis and fibrosis to lung tumors. These changes are somewhat similar for different species. Their severity can be related to the absorbed radiation dose (measured in rads) produced by alpha, beta or gamma radiation emanating from various deposited radionuclides. The chemicophysical forms of radionuclides and spatial-temporal factors are also important variables. As with other forms of injury to the lung, repair attempts are highlighted by fibrosis and proliferation of pulmonary epithelium. Lung tumors are the principal late effect observed in experimental animals following pulmonary deposition of radionuclides at dose levels that do not result in early deaths from radiation pneumonitis or fibrosis. The predominant lung tumors described have been of epithelial origin and have been classified, in decreasing frequency of occurrence, as adenocarcinoma, bronchioloalveolar carcinoma, epidermoid carcinomas and combined epidermoid and adenocarcinoma. Mesothelioma and fibrosarcoma have been observed in rats, but less commonly in other species. Hemangiosarcomas were frequency observed in dogs exposed to beta-gamma emitters, and occasionally in rats exposed to alpha emitters. These morphologic changes in the lungs of experimental animals were reviewed and issues relevant to the prediction of human hazards discussed.

Adenocarcinoma↗
PubMed1983

Long-term reactivity of lung and mediastinal lymph nodes following intratracheal instillation of sandy loam soil or Mount St. Helens volcanic ash.

The effects of Ritzville sandy loam soil and Mount St. Helens volcanic ash particles on the lung and mediastinal lymph nodes of Fischer rats were studied about 400 days after intratracheal instillation. A total of 22 or 77 mg of soil or ash was given in two or seven equally divided, consecutive, weekly intervals as a suspension in 0.5 ml saline. Significantly elevated levels of lipid-phosphorus and protein were found in lung lavages of rats given ash compared to those given soil. An enhanced histological degree of granulomatous reactivity, lipoproteinosis, fibrosis, and bronchiolar hyperplasia was seen in ash-exposed rats as compared to soil-exposed rats. Mediastinal lymph nodes of ash-exposed rats were 8-18 times larger than those of soil-exposed rats due to abundant cellular microgranuloma formation and early fibrosis. Mount St. Helens volcanic ash is apparently more biologically reactive than soil particles commonly found in eastern Washington.

Air Pollutants↗
PubMed1983

Inhalation carcinogenesis of high-fired 241AmO2 in rats.

Wistar rats were given a single inhalation exposure to high-fired 241AmO2 particles and examined over their life span. A total of 310 rats were used: 259 exposed to 241Am for life-span study, 30 exposed to 241Am for early metabolism study, and 21 unexposed life-span controls. The activity median aerodynamic diameter of the aerosols was 0.75-1.39 microns. About 55% of alveolarly deposited 241Am was cleared from the lung with a half-life of 0.5 days, 37% with a half-life of 7 days, and 8% with a half-life of 580 days. Group mean lung doses ranged from less than 5.7 rad up to 1500 rad. Significant early mortality due to radiation pneumonitis was seen only in the highest exposure group. The percentage of rats with lung tumors was 0% for controls (21 rats), 1% at lifetime lung doses less than 10 rad (139 rats), 7% at 10-50 rad (86 rats), 0% at 50-100 rad (9 rats), 60% at 100-500 rad (10 rats), and 7% at 500 rad (15 rats). Only one liver and one bone tumor were found in all exposed rats, both at lifetime tissue doses less than 10 rad. The fate and carcinogenicity of inhaled 241AmO2 in the lung of rats were similar to what has previously been described for inhaled 244CmO2.

Aerosols↗
PubMed1982

Clearance and distribution of intratracheally instilled vanadium compounds in the rat.

Intratracheally instilled 48V2O5 was rapidly cleared from the lung into blood, liver and bone. Approx. 40% of the recovered 48V was excreted, primarily in urine by day 3, while the skeleton accounted for 30% by day 7. The behavior of instilled 48VO2Cl was similar to that of 48V2O5. Uptake of gavaged 48V2O5 was 2.6% of administered dose. Skeleton, lung, kidney and liver are primary targets for intratracheally instilled 48V with uptake being much greater via the intratracheal route than by the oral route.

Animals↗
PubMed1982

Distribution of inhaled 239PuO2 in rat and hamster lung.

The distribution of inhaled 239PuO2 in rat and hamster lung was investigated up to one year postexposure in order to determine whether differences in pulmonary dose distribution could account for the apparent difference between the two species in lung tumor response. In previous life-span studies, rats developed up to 70% lung tumors at cumulative doses less than 2000 rads, whereas hamsters developed tumors in about 3% of animals at comparable or higher doses. Morphometric methods were used to quantitate the particle distribution in different lung regions of both species following exposure at levels that produced tumors in rats. The PuO2 particles were counted on autoradiograms of lung cross-sections and classified as to their location in either subpleural or internal parenchyma, lung vasculature, or major airways. Rat lung showed a greater long-term association of particles with the major airways than hamster lung. The particles also showed a greater tendency to occur in groups for rats, the difference being more pronounced in the subpleural region than in the remainder of the lung. In previous experiments, both bronchioles and subpleural fibrotic scars appeared to be the sites of origin for lung tumors. Different dose distributions within these regions may therefore affect the tumor response to inhaled 239PuO2.

Aerosols↗