Mary J. Daniels

Protein accumulation in lung lavage fluid following ozone exposure

Abstract Accumulation of protein in lung lavage fluid was used as an indicator of pulmonary damage following exposure of guinea pigs to O 3 . Exposure of animals to 510, 1000, or 1960 μg/m 3 (0.26, 0.51, or 1.0 ppm) of O 3 for 72 hr resulted in significantly elevated levels of lavage fluid protein when compared to that of air controls. This effect was not observed in animals exposed to 196 μg O 3 /m 3 (0.10 ppm). When exposure time was reduced to 3 hr, the O 3 -induced protein accumulation in lavage fluids was undetectable unless the time of lavage was delayed 10–15 hr following the exposure. Under these conditions, elevated protein content was seen in lung lavage fluids obtained from animals exposed to O 3 ranging from 510 to 1470 μg O 3 /m 3 (0.26-0.75 ppm) and a dose relationship between the amount of protein accumulation in the lung and the concentration of O 3 to which the animals were exposed was observed. Vitamin C deficiency did not enhance this O 3 -induced lesion in guinea pigs. The dose relationship has also been confirmed by polyacrylamide gel electrophoresis of the lavage fluids. Lung lavage fluid protein content in animals exposed to 353 μg O 3 /m 3 (0.18 ppm) for 8 hr/day for 5 or 10 consecutive days was not different from that of air controls.

Influence of cadmium, nickel, and chromium on primary immunity in mice☆

The effects of metals on the primary humoral immune system of mice were investigated using a hemolytic plaque technique to determine the number of specific antibody-producing spleen cells. Inhalation of NiCl/sub 2/ for 2 hr resulted in a significant negative linear dose response, the lowest effective concentration tested being 250 ..mu..g of Ni/m/sup 3/. Following a 2 hr aerosol exposure to NiCl/sub 2/, the lung cleared Ni on a first-order kinetics basis. A significant reduction in the number of plaques per 10/sup 6/ cells also was observed with exposure to 190 ..mu..g of Cd/m/sup 3/. Analyses of the data from intramuscularly exposed mice indicated that concentrations greater than or equal to 3.90 ..mu..g of Ni/g body weight (as NiSO/sub 4/) and greater than or equal to 9.25 ..mu..g of Ni/g body weight (as NiCl/sub 2/) resulted in significant immunosuppression. Intramuscular treatments with NiO, CdCl/sub 2/, and CrCl/sub 3/ had no effect at the concentrations tested.

Correlation between chemical suppression of natural killer cell activity in mice and susceptibility to cytomegalovirus: Rationale for applying murine cytomegalovirus as a host resistance model and for interpreting immunotoxicity testing in terms of risk of disease

The purpose of this study was to determine the relationship between chemical suppression of natural killer (NK) cell activity in mice and chemical effects on susceptibility to murine cytomegalovirus (MCMV) infection. The goal was to provide a rational basis for applying MCMV as a host resistance model for immunotoxicity testing and to provide risk assessors some guidance in relating suppression of NK cell activity to enhanced risk of disease. Data from studies with eight chemicals administered in various doses and by various routes were evaluated, and a significant correlation was observed between chemical suppression of virus-augmented NK cell activity and increased mortality due to MCMV infection. In contrast, effects of the same chemical treatments on spontaneous NK cell activity (i.e., basal activity in uninfected mice) did not correlate with effects of these chemicals on mortality due to MCMV. Although chemicals that suppressed spontaneous NK cell activity enhanced infection, the converse was not always true--that is, increased susceptibility to infection and suppression of virus-augmented NK cell activity were observed on three occasions when spontaneous NK cell activity was unaffected. This latter phenomenon plus the fact that for two chemicals spontaneous NK was suppressed at concentrations twofold below that which affected mortality appear to account for the poor statistical correlation. Nevertheless, the data indicate that MCMV is a useful host resistance model to be applied in immunotoxicity testing when suppression of NK cell activity has been demonstrated. However, virus-augmented activity may be a better indicator than spontaneous activity. The data also indicated that suppression of NK cell activity is predictive of increased susceptibility to infection and hence provides qualitative guidance (hazard identification) to risk assessors.

Effects of Phosgene Exposure on Bacterial, Viral, and Neoplastic Lung Disease Susceptibility in Mice

AbstractIn this study the effects of phosgene inhalation on host resistance models representative of bacterial, viral, and neoplastic lung diseases were assessed. A single Ch exposure to concentrations of phosgene of 0.025 ppm and above significantly enhanced mortality due to laboratory-induced aerosol infection with Streptococcus zooepidimi-cus (group C). Bacteria recovered from lavage fluid of mice exposed to 0.05 ppm for 4 h increased dramatically between 3 and 48 h post infection, while bacteria recovered from lavage fluid of air exposed mice declined to nearly undetectable levels over the same time period. Concentrations of phosgene 10-fold higher than the lowest observable effect concentration for streptococcus susceptibility had little or no effect on alveolar macrophage phagocytic activity and little or no effect on total cells recovered, viability, or differential cell counts in lavage fluid obtained shortly after exposure. A single 4-h exposure to as little as 0.025 ppm phosgene also caused a si...

Increased susceptibility to parathion poisoning following murine cytomegalovirus infection

In mice treated with ordinarily sublethal doses of parathion 2 to 5 days postinfection with murine cytomegalovirus (MCMV) 50 to 100% mortality was observed. These mortalities appeared to be due to a decrease in the ability of infected mice to detoxify parathion. Pentobarbital-induced sleeping time was also enhanced 3 and 6 days postinfection and cytochrome P-450 concentrations were markedly depressed in mice tested 3 days after infection. MCMV-induced effects on sensitivity to parathion and pentobarbital did not appear to be directly attributable to liver infection since concentrations of virus in the liver persisted at maximum concentrations well beyond the time when sensitivity to these compounds returned to normal. The time frame during which enhanced sensitivity to parathion and pentobarbital was observed suggests that this sensitivity may have been caused by viral-induced interferon-mediated depression of cytochrome P-450.

Morphine Alters the Immune Response to Influenza Virus Infection in Lewis Rats

Although the in vitro immunomodulatory effects of morphine are well-documented, few studies have explored the impact of morphine on viral infection in intact rats. We report that morphine can alter in vivo immune responsiveness to pulmonary influenza virus infection in Lewis rats. We studied rat-adapted influenza virus (RAIV) infection, which is a unique infectious disease system because normal rats develop an acute inflammatory response to RAIV in the lung, and rapidly clear the virus within a few days, with no mortality (13,20,21). Male Lewis rats were implanted with 75 mg morphine pellets or placebo pellets 72 hours prior to intranasal RAIV infection. Rats were euthanized at 2, 24, 48, 72 and 96 hours after infection and inflammation and viral load were measured in the lungs. Placebo-treated rats showed marked inflammatory responses to RAIV infection, and quickly cleared the virus from their lungs. Morphine-treated rats mounted less vigorous inflammatory responses to the infection and cleared the virus more slowly than placebo-treated rats. Although these initial data indicate that morphine can alter the response to RAIV, additional studies are necessary to fully characterize these effects.

Inhalation studies of Mt. St. Helens volcanic ash in animals. III. Host defense mechanisms.

The effects of inhalation exposure of mice or rats to 9.4 mg/m3 volcanic ash, 2.5 mg/m3 SO2, or both on host defense mechanisms were assessed. Cytologic changes in pulmonary lavage fluid included an increase in percentage polymorphonuclear leukocytes due to SO2 exposure and an increase in eosinophils due to ash. SO2 and ash also produced decreases in percentage alveolar macrophages. In the case of ash-exposed animals, this decrease was offset by an increase in lymphocytes. Total cell counts and viability were not affected by any of the exposures. Pulmonary clearance mechanisms were affected in that there were both decreased alveolar macrophage phagocytic capability following ash and ash + SO2 exposures and depressed ciliary beat frequency attributable to ash exposure. None of the inhalation exposures caused increases in susceptibility to an immediate or 24 hr postexposure aerosol challenge with Streptococcus. However, intratracheal instillation of both fine- and coarse-mode volcanic ash caused slight but significant increases in mortality due to bacterial challenge 24 hr after the instillation. The phytohemagglutinin-induced blastogenic response of splenic lymphocytes from exposed animals did not differ significantly from that of control lymphocytes, although the lipopolysaccharide-induced blastogenic response was enhanced. Ash exposure had no effect on susceptibility to murine cytomegalovirus. In summary, volcanic ash alone or in combination with SO2 had only minimal effects on certain host defense mechanisms.

Morphine reduces pulmonary inflammation in response to influenza infection

The present study shows that morphine reduces the pulmonary inflammatory response to intranasal influenza virus infection in rats. Rats were infected with rat-adapted influenza virus (RAIV), which is a unique infectious agent because normal rats develop an acute pulmonary inflammatory response to RAIV and rapidly clear the virus within a few days with no mortality. Male Lewis rats were implanted with 75 mg morphine pellets or placebo pellets 72 hours prior to intranasal RAIV infection. Rats were euthanized at 2, 24, 48, 72, and 96 hours after infection. Assessment of inflammation included accumulation of inflammatory cells in the lungs, lung weight, and protein and LDH content of bronchial alveolar lavage fluid (BALF). Placebo-treated rats showed a marked inflammatory response to RAIV infection, and morphine-treated rats mounted less vigorous inflammatory responses to the infection. Taken together, these data suggest that morphine treatment impairs the inflammatory response to RAIV infection in the lungs, which is consistent with prior work demonstrating that morphine is a potent anti-inflammatory agent in other areas of the body.

Enhanced mortality and liver damage in virus-infected mice exposed to p-xylene

This study assessed effects of exposure to p-xylene, a ubiquitous air pollutant, on mice infected with murine cytomegalovirus (MCMV), a mouse model for a common human virus. It was postulated that adverse health effects could occur as a result of (1) enhanced infection due to xylene-induced immune suppression, (2) increased p-xylene toxicity due to viral suppression of cytochrome P-450 (P-450), and/or (3) additive or synergistic effects on liver function due to tissue injury by both p-xylene and MCMV. Mice were exposed to filtered air, 600 or 1200 ppm p-xylene 6 h/d for 4 d and infected with a sublethal dose of MCMV after the first exposure. No deaths occurred among uninfected, p-xylene-exposed mice or infected, air-exposed mice; 34% and 0% mortality occurred respectively in infected mice exposed to 1200 and 600 ppm p-xylene. Virus titers in the liver and splenic natural killer cell activity were unaffected by exposure to 1200 ppm p-xylene. Small but significant increases in serum aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase activities, indicators of liver damage, were observed at 4 d postinfection. p-Xylene exposure had no effect on these serum enzyme activities in uninfected mice, but 1200 ppm potentiated this effect in infected mice. MCMV significantly suppressed and p-xylene significantly increased total P-450 levels in the liver, but there was no significant interaction between the two. Isozymes 1A1, 2B1/B2, and 2E1 were decreased to a similar degree, suggesting that the virus does not target specific isozymes. Enhanced mortality was not due to immune suppression. While p-xylene potentiated liver damage was caused by the virus, the magnitude of serum enzyme activities indicates that this damage was not a likely cause of death. The cause of deaths is unclear, results were consistent with the hypothesis that enhanced mortality was related to enhanced xylene toxicity due to suppression of P-450, although additive or synergistic damage to tissues other than liver cannot be ruled out.

Acute, Subchronic, and Chronic Exposure to a Simulated Urban Profile of Ozone: Effects on Extrapulmonary Natural Killer Cell Activity and Lymphocyte Mitogenic Responses

AbstractRats were exposed for 7, 3, 73, 52, or 78 wk to air or a simulated urban profile of O3 designed to mimic diurnal exposure patterns frequently seen in worst-case summer environments. Daily exposures consisted of a background level of 0.06 ppm for a period of 73 h, a broad exposure spike rising from 0.06 to 0.25 ppm and returning to 0.06 ppm over 9 h, and a 2 h downtime. Integration of the spike portion of the exposure pattern was equivalent to a 9-h square-wave exposure pattern of 0.79 ppm. Rats were exposed to this profile 5 days/wk; weekend exposures were to background levels only Spleens were removed and blood was drawn at the end of the exposure periods. Spleen cells were assessed for natural killer cell (NKC) activity and responses to T-cell mitogens, phytohemagglutinin and concanavalin A, and the B-cell mitogen, Salmonella typhimurium glycoprotein. Peripheral blood leukocytes (PSU were also assessed for responses to T-cell mitogens. Sections from spleen, femur (including bone marrow), thymus,...