Biomedical subjects
Publications and source records attributed to P L Roney.
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Excessive production of active oxygen radicals by macrophages is proposed to play an important role in asbestos-related diseases. The purpose of this study was to examine the capacity and mechanisms of action of various forms of asbestos to stimulate superoxide anion production by guinea pig alveolar macrophages. Chrysotile, but not the amphiboles (crocidolite, anthophyllite, or amosite), stimulated a rapid (less than 1 min) and dose-dependent (2.5-50 micrograms/ml) production of superoxide anion at noncytotoxic doses (2.5 to 25 micrograms/ml). The stimulation of superoxide anion production by chrysotile could be blocked by putative protein kinase C inhibitors (staurosporine, sphingosine, and fluphenazine). Chrysotile also stimulated phosphatidylinositol turnover as measured using 32Pi incorporation into phospholipids, [3H]-diacylglycerol levels, and intracellular calcium mobilization as measured using fura-2 and 45Ca. In addition, pertussis toxin partially blocked chrysotile-stimulated superoxide anion production. We conclude that the mechanism of guinea pig alveolar macrophage stimulation by chrysotile, but not the amphibole asbestos forms, is consistent with a mechanism which is similar to that used by agonists such as N-formyl-Nle-Leu-Phe resulting in stimulated phosphatidylinositol turnover, calcium mobilization, and activation of protein kinase C.
Three organophosphate compounds, dichlorvos, parathion and diisopropylfluorophosphate were tested as an unconditioned stimulus in the conditioned taste aversion (CTA) test. All organophosphates caused a dose-dependent CTA in rats at doses which did not induce any other signs of toxicity. Experiments with dichlorvos showed that the minimum dose which caused CTA did not alter the rats' sensitivity to pain or their behavior in either an open field or an inclined plane. Cholinesterase activity was inhibited in a dose-dependent manner in brain and plasma after administration of the organophosphates and CTA was correlated with the degree of plasma cholinesterase inhibition. CTA appears to be a sensitive indicator of neurobehavioral effects of mild exposure to organophosphates which causes only 30-40% inhibition of plasma cholinesterase.
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The 1980 National Natality Survey (NNS) and 1980 National Fetal Mortality Survey (NFMS) provide a unique opportunity to examine variation in exposure to radiation during pregnancy for mothers of live-born and stillborn infants. Maternal race, age, education, and marital status in both surveys and low birth weight in the 1980 NNS are characteristics used to examine exposure rates for X-ray, ultrasound, nuclear medicine, shortwave, and microwave radiation examinations and treatments. About 15 percent of mothers of live infants and 23 percent of mothers who experienced stillbirths (fetal deaths of 28 weeks or more gestation) had a medical X-ray procedure during pregnancy. The 15 percent exposed in 1980 was a reduction from 22.5 percent of mothers exposed according to the results of the 1963 NNS; this reduction occurred in all race and age groups. About 34 percent of 1980 NNS mothers and 53 percent of 1980 NFMS mothers had ultrasound exposure during pregnancy. Radiation exposure rates were higher for 1980 NNS mothers who had low birth weight infants (under 2,500 g, or 5 lb, 8 oz) than for those who had normal weight infants.