Critical controlled inhalation study of pathogenesis of neodymium oxide in mice and guinea pigs

Effects of exercise and inhaled yttrium oxide on blood lactic acid, erythrocyte volume, and lung histology in dogs

“…The increase in white cells which was found to be signifi cant indicates an active response of the body to remove foreign material. Davison (1963) found no significant difference in white cell counts of mice and guinea pigs exposed to inhaled neodymiura oxide and their controls. The increase noted here could be a peculiarity of species response, the effects of yttrium oxide, or any of the above combined with treadmill exercise.…”

“…The exposure and control chambers were those for which design requirements had been set by Davison (1963) and for which the design was accomplished and described by Cook (1961), The large chamber (Figure 3) was used for the six dogs where exposure to yttrium oxide occurred in the last six weeks of each experiment. The small chamber (Figure 4) was used for the two dogs which served as histologic controls in each experiment where exposure to yttrium oxide was not wanted.…”

“…Most of the pigment seemed to be transported gradually to the hilar lymph nodes, but it caused no significant reaction. Schepers (1955b) bronchial lymph nodes, heart, bone marrow, spleen, liver, adrenal, kidney, mesenteric lymph node, and testis or ovary, Davison (1963) found that gross and histological changes revealed a progressive impaction of neodymium in the lungs.…”

“…For this reason the lymphatics were viewed as being the only major route of removal of the neodymium oxide from the lung (Davison, 1963). Vorwald and Forest (1963) Lung Clearance Hatch and Gross (1964) state that alveolar clearance is that process by which the alveolar surface is kept free of exogenous and endogenous insoluble matter which could con stitute a barrier to free gaseous interchange.…”

“…They reported that particles larger than l.OyK were less toxic than those smaller than 1.0y4A. Davison (1963) estimated that 60^ of the generated neodymium oxide dust was contained in particles less than 1,0y(/in diameter. This was the quantity that was considered to permit deposition in the terminal bronchioles and alveoli.…”