1341 |
ACTIVATION OF MURINE LYMPHOCYTES BY THE HEAVY METAL MITOGENS, ZINC AND MERCURY DIVALENT CATIONS.REARDON, CHRISTOPHER LEE. January 1983 (has links)
Splenic and lymph node lymphocytes from Balb/C mice were activated in vitro by the heavy metal cations, Zn⁺⁺ and Hg⁺⁺, as noted by the several-fold increases in ³H-thymidine incorporation at 144 hours of culture. Optimal mitogenic concentrations of Zn⁺⁺ and Hg⁺⁺ were 200 μM and 10 μM, respectively. Data from experiments in which three different methods were used to enrich for either T or B splenic lymphocytes, i.e. cell passage over nylon wool columns, use of athymic Nu/Nu mouse spleen cells, or cell lysis with monoclonal anti-Thy-1 antibody plus complement, suggested that Zn⁺⁺ and Hg⁺⁺ were mitogens for T cells. Removal of macrophages from spleen cells by treatment with carbonyl iron followed by cell passage through nylon wool eliminated the lymphocyte responses to Zn⁺⁺ and to Hg⁺⁺. Moreover, addition of these macrophage-depleted lymphocytes to monolayers of resident peritoneal macrophages restored the lymphocyte responses to these mitogens. Both Zn⁺⁺ and Hg⁺⁺ activated splenic lymphocytes to display lectin-dependent cytotoxicity and to produce gamma interferon. Furthermore, Zn⁺⁺ induced low levels of natural killer activity in spleen cells. In contrast to spleen and lymph node cells, thymocytes and bone marrow lymphocytes did not respond to either cation under standard culture conditions. However, when cultured in the presence of E. coli-derived lipopolysaccharide (LPS) and 2-mercaptoethanol for 144 hours, thymocytes were activated by Zn⁺⁺ (200 μM) but not by Hg⁺⁺. Quantities of LPS as low as 1.0 ng/ml satisfied this culture requirement. Purified interleukin 1 could not replace the helping activity mediated by LPS. Thymocyte subpopulation studies showed that Zn⁺⁺ activated enriched peanut lectin receptor-negative mature thymocytes, but LPS was required for the response. Spleen cells from mice, intraperitoneally injected with ZnCl₂ for 7 to 14 days, were not activated in vivo as assessed by ³H-thymidine incorporation in vitro, nor did they display enhanced responses to T-cell or B-cell mitogens. However, zinc administration had negative effects by decreasing spleen cell numbers by 31% and thymic weight by 59%. A theoretical model is presented in which Zn⁺⁺ and Hg⁺⁺ may mediate their stimulating effects in vitro by altering histocompatibility "self" structures on the surface of lymphocytes and macrophages via interactions with sulfhydryl groups on these structures to which T lymphocytes with receptors for "altered self" structures respond with proliferation or cytotoxicity.
|
1342 |
ACUTE CHROMIUM (CHROMIUM(+VI)) TOXICITY IN THE ESTUARINE SHRIMP, MYSIDOPSIS BAHIA (CRUSTACEA: MYSIDACEA)Bauman, Stephanie January 1985 (has links)
No description available.
|
1343 |
Studies on the effects of zinc on experimentally-induced gastric ulcers in ratsCho, Chi-hin, 曹之憲 January 1978 (has links)
published_or_final_version / Pharmacology / Doctoral / Doctor of Philosophy
|
1344 |
Changing in potassium sensitivity in muscle of chronically morphinizedrats黃笑椿, Wong, Siu-chun, Susanna. January 1970 (has links)
published_or_final_version / Biochemistry / Doctoral / Doctor of Philosophy
|
1345 |
Effects of visible light on cells, subcellular organelles and enzymes鄭玉鸞, Cheng, Yuk-luen, Lydia. January 1979 (has links)
published_or_final_version / Biochemistry / Doctoral / Doctor of Philosophy
|
1346 |
Physiological and biochemical adjustments of the lip-shark Hemiscyllium plagiosum (Bennett) to changes of environmentalsalinitiesWong, Tak-ming, 黃德明 January 1975 (has links)
published_or_final_version / Zoology / Doctoral / Doctor of Philosophy
|
1347 |
A study of the acute and chronic effects of morphine on autonomic activities in rats梁文傑, Leung, Man-kit, Christopher. January 1986 (has links)
published_or_final_version / Pharmacology / Doctoral / Doctor of Philosophy
|
1348 |
Modeling of narrow-width effect in MOSFET黎沛濤, Lai, Pui-to. January 1984 (has links)
published_or_final_version / Electrical Engineering / Doctoral / Doctor of Philosophy
|
1349 |
A study of gate-oxide leakage in MOS devicesFleischer, Stephen. January 1993 (has links)
published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy
|
1350 |
Studies on the mechanisms of cigarette smoke-induced apoptosis and cell proliferation in gastric epithelial cellsWang, Hongying, 汪紅英 January 2000 (has links)
published_or_final_version / Pharmacology / Doctoral / Doctor of Philosophy
|
Page generated in 0.0461 seconds