30-day Exposure Period Research Articles

Functional and metabolic properties of alveolar macrophages in response to the gas phase of tobacco smoke.

The effect of whole tobacco smoke and the gas phase of tobacco smoke on the metabolism and phagocytic ability of alveolar macrophages was monitored over a 30-day exposure period. It was demonstrated that both the gas phase and whole tobacco smoke induced a weight loss in exposed rats. Alveolar macrophage oxygen consumption was markedly increased by both exposure regimens. Superoxide generation was not affected by whole tobacco smoke exposure but was increased in response to the filtered gas phase. Hexose monophosphate shunt activity was not altered by either treatment. When metabolic alterations were seen in response to the separate exposures, they were seen only after a phagocytic challenge to the macrophage and not when the cell was unchallenged. Neither whole tobacco smoke nor the gas phase had any significant effect on the ability of alveolar macrophages to phagocytize a viable challenge of Staphylococcus aureus. Our results suggest that many of the metabolic and functional effects of tobacco smoke on alveolar macrophages can be attributed to the gas-phase component of whole tobacco smoke.

Endrin and malathion toxicity to flagfish (Jordanella floridae).

Endrin and malathion effects on survival, growth, and reproduction of flagfish were determined in a flow-through system. Endrin chronic effects on first-generation growth and reproduction occurred only at 0.3 microgram/L, the highest concentration tested. The mean endrin residues in the first-generation fish at 65 days were about 15,000 times the water concentration in all concentrations tested. Malathion concentrations of 31.5 microgram/L and 24.7 microgram/L, the highest concentrations tested, had detrimental effects on first-generation survival. During the same period malathion concentrations as low as 10.9 microgram/L significantly affected growth. Neither insecticide, at the concentrations tested, had any detectable effects on the second generation during a 30-day exposure period. Acute toxicities to juvenile fish were also determined in the same flo-through system. The 96-hr LC50's were 0.85 microgram/L for endrin and 349 microgram/L for malathion.