Biomarkers of exposure to metal contamination and lipid peroxidation in the benthic fish Cathorops spixii from two estuaries in South America, Brazil

Biomarkers as lipid peroxidation, metallothionein and delta-aminolevulinic acid dehydratase were determined in Cathorops spixii to compare the biological responses of this fish from estuaries with distinct anthropogenic influence. Three areas were selected in two estuaries in accordance with the levels of contamination for the polluted (Santos/So Vicente) and with the hydrodynamic characteristics for the non-polluted (Canan,ia) estuary. Water characteristics and mercury levels in C. spixii confirmed a high human influence in the polluted system. In general, the biomarkers showed differences between the estuaries, suggesting disturbances in the specific cell mechanisms due to the presence of multiple xenobiotics in the contaminated system. Therefore, these biomarkers are recommended to promote more accurate information about the exposure to pollutants. Additionally, the study of the effect of the multiple xenobiotics on resident species such as the benthic fish C. spixii can favor a better assessment of the environmental quality of these systems.

(Table T1) Radioelement concentration and radiogenic heat production of ODP Holes 173-1067A and 173-1068A

Mean values of radiogenic heat production are derived from measurements of radioelements on the following rock types: amphibolite (0.358 ± 0.118 µW/m**3) and tonalite gneiss (0.802 ± 0.039 µW/m**3) at Site 1067 and serpentinized peridotite (0.0108 ± 0.0003 µW/m**3) at Site 1068. The results for serpentinized peridotite and amphibolite are consistent with previous measurements on samples from Sites 897 and 900. These results suggest that the thin continental crust in this region would contribute very little to the conductive heat flow.

B7–CTLA4 interaction enhances both production of antitumor cytotoxic T lymphocytes and resistance to tumor challenge

Expression of B7-family costimulatory molecules CD80 (B7–1) and CD86 (B7–2) on tumor cells enhances host immunity. However, the role of the two B7 receptors, CD28 and CTLA4 (CD152), on T cells in antitumor immune response has not been clearly elucidated. Based on the effects of anti-CD28 and anti-CTLA4 mAbs on T cell response, it was proposed that CD28-B7 interaction promotes antitumor immunity, whereas B7-CTLA4 interaction down-regulates it. A critical test for the hypothesis is whether selective engagement of CTLA4 receptors by their natural ligands CD80 and CD86 enhances or reduces antitumor immunity. Here we used tumors expressing wild-type and mutant CD80, as well as mice with targeted mutation of CD28, to address this issue. We report that in syngeneic wild-type mice, B7W (W88>A), a CD80 mutant that has lost binding to CD28 but retained binding to CTLA4, can enhance the induction of antitumor cytotoxic T lymphocytes (CTL); B7Y (Y201>A), which binds neither CD28 nor CTLA4, fails to do so. Consistent with these observations, B7W-transfected J558 plasmocytoma and EL4 thymoma grow significantly more slowly than those transfected with either vector alone or with B7Y. Optimal tumor rejection requires wild-type CD80. Moreover, expression of a high level of CD80 on thymoma EL4 cells conveys immunity in mice with a targeted mutation of CD28 gene. Taken together, our results demonstrate that B7-CTLA4 interaction enhances production of antitumor CTL and resistance to tumor challenge and that optimal enhancement of antitumor immunity by CD80 requires its engagement of both CD28 and CTLA4.

Nuclear public information and rational public policy decisions [microform] : hearing before the Subcommittee on Energy Research and Production of the Committee on Science and Technology, U.S. House of Representatives, Ninety-seventh Congress, first session, December 15, 1981.

"No. 72."

Oversight--the Nuclear Regulatory Commission research program [microform] : hearings before the Subcommittee on Energy Research and Production of the Committee on Science and Technology, U.S. House of Representatives, Ninety-seventh Congress, second session, May 18, 19; June 15, 1982.

"No. 128."

The future of the Department of Energy's multiprogram laboratories [microform] : hearing before the Subcommittee on Energy Development and Applications and the Subcommittee on Energy Research and Production of the Committee on Science and Technology, U.S. House of Representatives, Ninety-seventh Congress, second session, December 2, 1982.

"No. 154."

Impacts of budget uncertainties on Department of Energy's national laboratories [microform] : hearing before the Subcommittee on Energy Development and Applications and the Subcommittee on Energy Research and Production of the Committee on Science and Technology, U.S. House of Representatives, Ninety-seventh Congress, second session, June 2, 1982.

"No. 114."

Mining laws of 1872 and 1989 : hearing before the Subcommittee on Mineral Resources Development and Production of the Committee on Energy and Natural Resources, United States Senate, One Hundred First Congress, first session, on S. 1126 ... June 7, 1989.

"September 13, 1990".

Mining Law Reform Act of 1991 and the Minerals Policy Review Commission Act of 1991 : hearing before the Subcommittee on Mineral Resources Development and Production of the Committee on Energy and Natural Resources, United States Senate, One Hundred Second Congress, first session, on S. 433 ... S. 785 ... June 11, 1991.

Item 1040-A, 1040-B (MF).