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Reelin plays an important role in the migration of embryonic neurons, but its continuing presence suggests additional functions in the brain. We now report a novel function where reelin protects P19 embryonal cells from apoptosis during retinoic acid-induced neuronal differentiation. This increased survival is associated with reelin activation of the phosphatidyl-inositol-3-kinase (PI3 K)/Akt pathway. When PI3 K was inhibited with LY294002, reelin failed to protect against this retinoic acid-induced apoptosis. The protective effect of reelin includes activating the Src-family kinases/PI3 K/Akt pathway which then led to selective phosphorylation of Bcl-2/Bcl-XL associated death promoter (BAD) at serine-136, while the phosphorylation-incompetent mutation of BAD (S136A) suppressed this protection. These and additional studies define a novel pathway where reelin binds apoE receptors, significantly activates the PI3 K/Akt pathway causing phosphorylation of BAD which helps to protect cells from apoptosing, thus serving an important role in promoting the survival of maturing neurons in the brain.

To evaluate the rheological properties and the oxidative susceptibility of gamma-ray-irradiated red blood cells (RBCs).RBCs in mannitol-adenine-phosphate (MAP) medium were irradiated with 35 Gy and stored at 4 degrees C for 4 weeks. The deformability of the RBCs was examined under shear flow in relation to the morphological and biochemical changes. The RBCs were further exposed to 1 mM FeSO(4) and 5 mM ascorbate to examine the oxidative susceptibility.The RBC deformability was decreased during storage, and the impairment was further enhanced by the irradiation, which promoted cell shrinkage and intracellular hemoglobin condensation accompanying potassium loss. Lipid peroxidation and protein aggregation of the RBC membrane as well as echinocytosis were not enhanced by the irradiation. The exposure to free iron did not stimulate the oxidation of the irradiated RBC membrane.The decreased deformability of gamma-ray-irradiated RBCs in MAP medium was mainly induced by dehydration due to potassium loss, and the membrane lipids and proteins were stably preserved against oxidative stress.

Microglia transform from ameboid to ramified cells during development and display an ameboid appearance again under certain pathological conditions. Some cytokines produced by astrocytes may be responsible for the microglial transformation. In the present study, we compared the effects of cytokines, granulocyte/macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF), and interleukin-3 (IL-3) on the morphology of rat cultured microglia. For quantitative evaluation, we employed "transformation index" as calculated by (perimeter of cell)2/4 pi (cell area). GM-CSF facilitated the ramification of cultured rat microglia, which was effectively induced in a serum-free medium. However, M-CSF and IL-3 did not induce the ramification. A certain serum adhesion protein (possibly vitronectin) as well as other high molecular weight substances in fetal calf serum inhibited the GM-CSF-induced microglial ramification. Among ordinary supplements for a chemically defined medium, progesterone, insulin, and a high concentration of glucose suppressed the ramification. These findings suggest that GM-CSF may be involved in microglial ramification and that many kinds of supplements that are added to culture media profoundly affect the morphology of microglial cells.

The deformation of erythrocytes in microvessels less than 15 microns in inner diameter was analyzed using a microvascular bed isolated from rabbit mesentery. The deformation was compared with that found in glass capillaries.Human erythrocytes were perfused through two media: first, a microvascular-bed section isolated from rabbit mesentery; and second, a set of glass capillaries. Images of deformed erythrocytes were recorded on videotape under strobe light and analyzed with an image processor. The flow velocity of the erythrocytes was determined from the difference of their positions between video frames or by a dual-spot cross-correlation technique. Erythrocyte deformability was modified with diamide, diazene dicarboxylic acid bis[N,N-dimethylamide], by crosslinking spectrins.Symmetrical (parachute-like or slipper-like) deformation of erythrocytes was observed only in microvessels smaller than 13 microns in inner diameter. Erythrocytes in microvessels were less deformed than those in glass capillaries with corresponding diameters, and the marginal cell-free layer was narrower. The deformation increased by increasing the flow velocity of erythrocytes, and the cell-free layer became wider. Diamide-treated cells in microvessels were less deformed than normal cells and showed slightly narrower cell-free layers. Stronger stress in narrower microvessels induced further deformation of cells.Erythrocyte deformation in microvessels was essentially different from that in glass capillaries, and the effect of erythrocyte deformability on the flow dynamics of erythrocytes in microvessels was properly evaluated using an isolated microvascular bed.

CPD blood, in glass containers and polyvinyl chloride (PVC) bags, was X-irradiated with 50 Gy (n = 4), and then stored for up to 4 weeks. Rheological, hematological and biochemical changes of the red cells during storage were examined. Changes in blood viscosity and various properties of red cells (deformability, shape, hematological indices and concentrations of 2,3-diphosphoglycerate and nucleotides) during storage at 4 degrees C were not altered by the irradiation. The rheological, biochemical and morphological properties of red cells were as well preserved in PVC bags as in glass containers. No abnormal and/or cross-linked proteins in red-cell membranes were induced by the irradiation. Irradiation of PVC bags did not affect the above properties of red cells through any changes in the bag constituents. In conclusion, X-ray irradiation with 50 Gy to CPD blood in PVC bags does not affect the rheological functions of red cells.

The protective effects of three types of pooled human gamma-globulin preparations (intact: GG, S-sulfonated: GGS, and pepsin-treated: GGP) for intravenous use against experimental aerosol infection of mice with Bordetella pertussis have been evaluated. The gamma-globulin preparations GG and GGS showed significant protective activity whereas GGP did not, as evaluated by survival numbers, body weight gains and suppression of leucocytosis. GG and GGS but not GGP also possessed neutralizing activity against leucocytosis-promoting and histamine-sensitizing activities of pertussis toxin (PT). Evaluation of protective activities of GG, GGS and GGP prepared from rabbit gamma-globulin, highly immunized with PT and not containing any anti-F-HA (filamentous haemagglutinin) or agglutinin antibodies, demonstrated that anti-PT-GG and anti-PT-GGS but not anti-PT-GGP protected against experimental infection by B. pertussis. These studies showed that the protective activity was correlated with anti-PT titre but that the Fc portion of the gamma-globulin molecule is necessary for actual protection against whooping cough by B. pertussis.