Experimental leukocyte-induced pulmonary vasculitis with inquiry into mechanism

Intravenous transfusions of washed allogeneic or autologous leukocytes in rabbits resulted in lesions of pulmonary periarteritis 48 hours later. Intact leukocytes were required. Systemic anaphylaxis, generalized Shwartzman reaction, alternate pathway complement activation and inert particle microembolism failed to produce identical lesions. Leukocytes tagged with radioactive chromium were found within arterial thromboses with proximal vasculitis. Generation or release of inflammatory factors plus thromboembolism would explain the pathogenesis of the lesions described. Specific mechanisms may be quite complex. Similar lesions have not been described in studies of pulmonary leukocyte entrapment or experimental microembolism of the lung. This model may be useful for studying pathogenetic mechanisms in pulmonary vasculitis and may have clinical implications.     

Cytolytic activity of pulmonary and systemic lymphoid cells from C57BL/6 mice following intrapulmonary or intraperitoneal immunization with allogeneic tumor cells

In order to demonstrate whether specific cytotoxic T cells could be induced in lung parenchyma, C57BL/6 mice were immunized by the intrapulmonary route with allogenetic tumor cells (P815). Ten days after administration of 20 x 10(6) allogeneic cells, peak concentrations of cytotoxic cells were found in lung, tracheobronchial lymph node, and spleen. With reduction in immunizing dose, lytic activity disappeared from spleen and lymph node, but persisted in lung. The cytolytic activity was specific for the immunizing alloantigen, was abolished by antitheta serum, and could not be attributed to macrophages. For comparison, C57BL/6 mice were immunized by the intraperitoneal route with 20 x 10(6) P815 cells. The expected cytolytic activity was found in spleen and lymph nodes: however, unexpectedly high levels of cytolytic activity were also found in pulmonary lymphocytes. This activity was confirmed using a wide range of effector to largest cell ratios in the assay system. Quantitative cytolytic assays demonstrated that the maximum rate of cytolysis by pulmonary lymphocytes obtained from mice immunized intraperitoneally exceeded by 10- to 20-fold the rate of cytolysis by pulmonary lymphocytes obtained from mice receiving intrapulmonary immunization. These data demonstrate that cytolytic T-lymphocytes appear in lung parenchyma after either intrapulmonary or intraperitoneal immunization and that the intraperitoneal route is far more efficient than the intrapulmonary route. This cell-mediated immune mechanism potentially is available for host defense of respiratory tissue.     

Hydroxyurea (HU) in experimental hematology. II. Similarities and dissimilarities between HU and 3H-thymidine killing

The lethal effects of hydroxyurea (HU) and 3H-thymidine (3H-dT) on mouse hematopoietic cells were compared after various experimental procedures. The aim was to explore the relative efficiency of these two methods in analyzing the kinetic properties of progenitor cells. Both methods indicated that 40-50% of progenitor cells assayed with diffusion chamber culture (DCPC) were in S phase 3 days after cyclophosphamide treatment. Effects of HU, but not 3H-dT, were altered by neostigmine triggering of normal DCPC into cell cycle. On the other hand, cooling marrow cells before exposure to HU or 3H-dT largely abrogated the effect of HU, but not of 3H-dT. Blood-borne DCPC were not in cycle according to the HU effect. Separated blood DCPC were apparently in cycle, as judged with 3H-dT, but the Isopaque-Ficoll separation procedure rendered normal marrow DCPC susceptible to 3H-dT killing. When marrow cells were cultured in DC the HU technique appeared to be suitable for evaluation of modulation of progenitor cell (CFU-S or CFU-C) proliferation, whereas our previous experiments have shown that the 3H-dT technique is a convenient method to assess the initial triggering of CFU-S into cycle in DC culture.     

Compilation of thermodynamic and phase information for the binary systems of molybdenum

The publication of the computation of molybdenum data has prompted a number of questions about the motivation for the project and general philosophy used in evaluating data. This article presents some general comments about the project and about the format of the compilations.