Walter C. Eisenberg

Evaluation of host resistance and immunity in mice exposed to the carbamate pesticide aldicarb.

Adult female Swiss-Webster and B6C3F1 mice received distilled water only or water containing 0.1, 1.0, 10, 100, or 1000 ppb of aldicarb daily for 34 days. The target concentration of aldicarb present in the 10 ppb dosing solution was analytically verified on a daily basis as was its stability over a 48-hr period. To develop an immune profile of this compound, functional parameters measured after exposure included resistance to infectious viral challenge; quantitation of splenic antibody-forming cells to sheep erythrocytes and circulating serum antibody levels; splenic lymphocyte blastogenesis to T- and B-cell mitogens; and mixed-lymphocyte culture response. To supplement the functional assays, complete blood counts, differential leukocyte counts, and body and relative organ weights were measured. In addition, gross and histopathologic examinations of tissues relevant to the immune system were performed. The absence of significant effects on any of these parameters suggests that aldicarb at environmentally relevant exposure concentrations is not immunotoxic in rodents.

Gas phase generation of O2(+Δg) at atmospheric pressure by direct laser excitation☆

Abstract O 2 ( 1 Δ g ) was generated in the gas phase at atmospheric pressure by direct laser excitation. A Holobeam model 255 Nd—YAG laser with an output at 1065 nm was used to achieve the transition O 2 ( 3 Σ g − , v = 0) → O 2 ( 1 Δ g , v = 1) The mean lifetime τ of the resulting excited oxygen species in the gas phase at atmospheric pressure was measured to be 0.124 ± 0.012 s. This corresponds to a bimolecular rate constant k 2 for the overall reaction O 2 ( 1 Δ g , v = 1) + O 2 ( 3 Σ g − ) → 2O 2 ( 3 Σ g − ) of (3.3 ± 0.4) × 10 −19 molecule −1 cm 3 s −1 , a factor of 10 below the currently accepted value for ground state oxygen deactivation of singlet oxygen. Possible reasons for this difference are discussed.

Biological effects of singlet delta oxygen on respiratory tract epithelium

Exposure of hamster tracheal organ cultures to gas phase singlet delta oxygen,1O2, at atmospheric pressure produced significant alterations in the mucociliary epithelium resulting in changes in ciliary activity and cellular morphology.

Gas phase observation of the 1.27-μ emission of singlet delta oxygen generated at atmospheric pressure by heterogeneous photosensitization

Singlet oxygen was generated in the gas phase using heterogeneous photosensitization and atmospheric pressure. The emission of O2 (1Δ → 3Σg) at 1.27-μ has been observed.

Gas phase generation of singlet oxygen at atmospheric pressure

Abstract Evidence is presented for the gas phase generation of singlet oxygen using heterogeneous photosensitization and atmospheric pressure.

LYSIS OF EGG PHOSPHATIDYLCHOLINE LIPOSOMES BY SINGLET OXYGEN GENERATED IN THE GAS PHASE

Abstract Singlet molecular oxygen was generated in the gas phase by heterogeneous energy transfer from a film of dry Rose Bengal and bubbled into suspensions of egg phosphatidylcholine liposomes, leading to membrane lysis and lipid peroxidation. The analysis based on large target diffusion kinetics indicates that approximately 3000 interactions were required for lysis of 1.5 μm liposomes. This experimental method makes it possible to measure the reactivity of gas phase singlet oxygen with aqueous biological systems.

Propellant combustion product analyses on an M16 rifle and a 105 mm caliber gun

Abstract Some of the propellant combustion products (particulates and gases) that are formed on firing an M16 rifle and 105mm caliber gun have been subjected to qualitative, and to a more limited extent, quantitative chemical analyses. For both weapons, large numbers of trace gas species, 90 to 70 respectively, were identified in the combustion effluents from the small large bore weapons. Quantifiable data were obtained for 15 of these species in terms of mass of compound formed per unit mass of propellant burned. Polynuclear aromatic hydrocarbons, 11 and 4 respectively, were identified and quantified in the combustion products from the small and large bore weapons. Metal particulates (5) in the respirable range in the combustion products from the M16 rifle were analyzed and quantified. Many of the chemical species identified in the study have known toxicological properties. Although the data base is limited, it appears that within the confines of the different propellants’ stoichiometries, the amounts of...

Evidence of DNA repair in organ cultures of hamster tracheal epithelium following exposure to gas phase singlet oxygen.

Autoradiographic identification of unscheduled DNA synthesis (UDS) in short-term organ culture of hamster tracheal epithelium has been used as a predictive test for mutagenic and/or carcinogenic compounds. Tracheal explants were treated for 2 h with singlet delta oxygen plus [3H]thymidine. Silver grains over the nuclei of epithelial cells from the superficial layer of the mucosa were observed, indicating UDS. Control cultures, exposed to the gas phase without singlet oxygen, failed to elicit UDS.

Formation of benzene polycarboxylic acids in the oxygen oxidation of solid by-products from coal-conversion processes (CCP) in an alkaline medium

Abstract Solid and liquid carbonaceous by-products have been obtained in both coal gasification and liquefaction processes. A study of the oxidation of the solid by-products was undertaken to determine what commercial chemicals could be derived from these materials. The oxygen oxidation of various coal-conversion-process by-products in 10% aqueous sodium hydroxide was investigated at 250 °C and a total pressure of 8.27 MPa (gauge). The products isolated were carbon dioxide and the organic extract, a complex mixture of aliphatic and aromatic acids. The benzene polycarboxylic acids were the major component of the organic extract.