Effect of near ambient exposures to sulfur dioxide and ferrous sulfate particles on murine pulmonary defense mechanisms

Astrocytic ceruloplasmin expression, which is induced by IL-1beta and by traumatic brain injury, increases in the absence of the IL-1 type 1 receptor

IL-1alpha and IL-1beta are induced immediately after insults to the brain, and signaling through the type 1 IL-1 receptor is essential for a normal microglial and astroglial response to injury. To better understand which genes are induced in astrocytes by IL-1beta, we used the unbiased technique of differential display to analyze mouse astroglial gene expression after IL-1beta treatment. Two novel genes were induced, as well as the gene for ceruloplasmin, a ferroxidase with antioxidant properties. Ceruloplasmin was analyzed further by Northern and Western blot. RNA and protein levels of ceruloplasmin were increased when astrocytes were treated with IL-1beta. To determine whether the IL-1 type 1 receptor (IL-1R1) is essential for the injury-induced expression of ceruloplasmin, a Western blot analysis was performed after a traumatic brain injury on mice that were IL-1R1-deficient. Ceruloplasmin increased significantly above controls after injury; however, injury-induced levels of ceruloplasmin were lower in IL-1R1-deficient (2.7-fold increase) than in the wild-type animals (3.5-fold increase). These data indicate that while IL-1R1 deletion has a slight effect on ceruloplasmin expression, it is not essential for either the basal or the induced expression of ceruloplasmin in vivo. Since ceruloplasmin buffers free copper, oxidizes ferrous iron, and catalyzes the dismutation of free radicals, increased levels of ceruloplasmin likely protect neurons and glia from sustaining damage after injury. Furthermore, as the IL-1R1 has been proposed to be a target for achieving neuroprotection after injury, these data suggest that the protection afforded by ceruloplasmin will be retained even when the IL-1R1 is antagonized.

Sequential health effect study in relation to air pollution in Bombay, India

A health study done for 4 years in 4129 subjects from 3 urban (high, medium and low according to SO2 levels) and a rural community showed a higher morbidity with raised levels. Initially in the respective 4 areas standardised prevalences (in percent) were: for dyspnoea 7.3, 6, 3.2 and 5.5; for chronic cough 5.1, 2.7, 1.7 and 3.3; for intermittent cough 15.6, 5.8, 0.4 and 3.7 and frequent colds 18.0, 20.8, 12.1 and 11 percent. The diagnosis of chronic bronchitis was done in 4.5, 4.5, 2.3 and 5.0 percent and cardiac disorders 6.8, 4.3, 8.2 and 2.7 percent in respective 4 areas. After 3 years, 55-60% of urban and 44% of rural subjects were reassessed. Several minor symptoms, besides above ones were related closely to the urban air pollutant profile. Increased greenery protected only at lower levels of pollution. Initial lung functions were best in "urban low" area but in all urban areas, yearly declines were larger than in rural subjects. A cross sectional study for effect of slums in 4 areas on 22272 subjects revealed generally higher morbidity in slum residents, particularly in "urban medium" area for frequent colds, cough and dyspnoea. Daily health diaries maintained in 2232 subjects revealed high morbidity in 2 more polluted areas; monthly trends correlated to SO2 and S.P.M. and daily fluctuations with SO2 revealed a threshold between 50 to 100 micrograms/CM/day. There were greater mortality (S.M.R.) in cardiorespiratory and malignant diseases related to pollution. The major factors affecting morbidity were pollution, nutrition, occupation, smoking and age.

Effects of subchronic exposure to a mixture of O3, SO2, and (NH4)2SO4 on host defenses of mice

Mice exposed 5 h/d, 5 d/wk up to 103 d, to 0.2 mg O3/m3 or to a mixture of O3, 13.2 mg SO2/m3, and 1.04 mg (NH4)2SO4 aerosol/m3 showed significantly greater susceptibility to group C streptococcal aerosol infection relative to filtered air controls. Pulmonary bactericidal activity by alveolar macrophages was significantly enhanced in the lungs of mice exposed to the mixture relative to those inhaling filtered air or O3 alone. The total number and distribution of the free cells lavaged from the lungs, as well as cellular ATP levels, did not change due to the pollutant exposures. In vitro cytostasis in tumor target cells cocultured with peritoneal macrophages from the exposed mice was significantly enhanced in the O3-exposed and in the mixture-exposed treatment groups relative to controls and also in the mixture-exposed relative to the O3-exposed group when a target-to-effector-cell ratio of 1:10 was used; no such effects were observed when this ratio was 1:20. Splenic T-lymphocyte function, as measured by blastogenesis to mitogens and alloantigens, was affected by exposure to O3 and/or the mixture, although the patterns of effects were qualitatively different. Splenic B-cell function and macrophage antigen processing, as measured by the generation of antibody plaque-forming cells, was unaffected by exposure.

Effect of ferrous sulfate aerosols and nitrogen dioxide on murine pulmonary defense

A murine infectivity model was used to test the effect of exposure to atmospheres containing 290 +/- 50 microgram/m3 of respirable sized ferrous sulfate (FeSO4) particles (0.4 micron mass median aerodynamic diameter) and 1.0 ppm nitrogen dioxide (NO2) prior to infection with aerosols of Staphylococcus aureus or group C streptococci. Exposure to these combined pollutants for 24 or 48 hr did not impair pulmonary inactivation of S. aureus. Exposure to FeSO4 or NO2 for 48 hr, or to both pollutants for 24 or 48 hr, resulted in significant decreases in inactivation of inhaled group C streptococci. Mortality studies following pollutant exposure demonstrated earlier, but not an increased number of deaths. These studies demonstrate the importance of the test organism in assessing air quality standards with the infectivity model and enhanced toxicity and prolongation of exposure to relatively low levels of submicron-size particles of FeSO4 and NO2.