Inhalation of 181W Labeled Tungstic Oxide by Six Beagle Dogs

Abstract

Six purebred beagle dogs were exposed to 1.9-8pCi of 1sLW03 by nose only inhalation. The aerosol had an activity median aerodynamic diameter of 0.70pm and a geometric standard deviation of 1.5. The activity deposited in the respiratory tract of each animal was estimated by three independent techniques. Retention and excretion were measured over 165 days. Following inhalation, 60% of the inhaled activity was deposited in the respiratory tract. Of this, about half was located, by gamma ray spectroscopy, in the lower portion of the tracheobronchial compartment and in the pulmonary compartment. Removal of the inhaled activity from the body was quite rapid. Partial body retention was determined from in-vivo gamma counting over the lung area and over the posterior portion of the dog's body. Whole-body retention was also estimated by subtracting the excreted activity from the inhaled activity at various times. The following retention patterns were determined, where t is the time in days:Visceral position R = 0,94e-(0.693/0.357)t + 0.04e-(0.693/6.3)t + om02e-(0.693/139)t Excreta collection R = 0.90e-(0.693/0.603)t + 0.06e-(0.693/5.8)t + 0.O4e-(0.693/63)taThe ratio of cumulative urinary excretion to cumulative fecal excretion for 165 days ranged from 0.57 to 1.8. This variation may have been related to differences in the clearance patterns of the individual dogs. Blood measurements indicated that the inhaled tungstic oxide entered the blood quite soon after inhalation and was rapidly removed. Measurements of selected organ and tissue samples at sacrifice (165 days post-inhalation) showed the highest concentration of tungsten in lung and kidney. Bone, gall bladder, liver and spleen were all about a factor of ten less than the lung, while the remaining organs decreased in the order: testes, pancreas, large intestine, small intestine, diaphragm, stomach, heart, and skeletal muscle.In terms of total organ burdens; most of the activity was found in bone (37%), lung (31 %), kidney (15%), liver (9.773, and skeletal muscle (5.7%). Body burdens calculated from organ and tissue burdens were in good agreement with in uiuo gamma measurements at sacrifice.

Intracellular Particle Dissolution in Alveolar Macrophages

“…In fact, a translocation rate constant k = 6.9 x 10-8 g/cm2/day was determined for all canine lung clearance studies using Co304 particles (32). Interestingly, this constant was in the same range as the translocation rate constants found for other metal oxides in dogs (21)(22)(23)(24)(25)(26)(27)(28) (33).…”

“…This approach has also been applied to less soluble particles. Reasonable agreement was obtained when translocation in vivo was compared to dissolution of insoluble particles in lung fluid simulants (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). It has to be stated, however, that the particles used were not uniform and that their physical parameters, in particular their specific surface areas, were not known exactly, resulting in considerable uncertainty.…”

Reproductive Effects and Duckling Survivability Following Chronic Dosing With Tungsten-Iron and Tungsten-Polymer Shot in Adult Game-Farm Mallards

“…The concentration of tungsten in the eggs followed the same trend as in the adult tissue samples (Mitchell et al, 2001b) in that tungsten was detected in nine shells of eggs from tungsten-iron-dosed females at a concentration higher than the concentration of tungsten detected in three shells of eggs from tungsten-polymer-dosed females. The presence of tungsten in shells can be attributed to the fact that calcium-containing tissues are among the principle sites of tungsten deposition (Kinard and Aull, 1945;Bell and Sneed, 1970;Aamodt, 1975).…”

Hematological Effects and Metal Residue Concentrations Following Chronic Dosing With Tungsten-Iron and Tungsten-Polymer Shot in Adult Game-Farm Mallards

“…The bone, liver, and kidneys are principle sites of tungsten deposition in a number of different species (Kinard and Aull, 1945;Wase, 1956;Kaye, 1968;Bell and Sneed, 1970;Aamodt, 1975) and the primary site of tungsten deposition is speciesspecific. In the present study, the concentration of tungsten was highest in the liver, intermediate in the femur, and lowest in the kidneys and gonads.…”