פרסומים

Oil emulsions comprising 10 or 20% soybean oil, 1.2% egg or soybean phosphatides, and 2.25% glycerol in distd. H2O to 100% with pH adjusted to 7-7.5 by NaOH were optimally homogeneous when lecithin comprised phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositols, and lysophosphatidylcholines at a ratio of 6:2:1:0.03; and when the lecithin component was well dispersed in liposome form in the aq. phase prior to emulsion prepn. This dispersion was best obtained by high pressure homogenization (microfluidization) of the emulsifier. [on SciFinder(R)]

The release of electrolytes from water-oil-water (W/O/W) emulsions was studied. A significant difference was obsd. in the release of NaCl and org. ion (ephedrine-HCl [50-98-6]). The rate of release decreased with the increase of the initial concn. of the electrolyte. A kinetic model which is similar to the model for release of dispersed drugs from a polymeric matrix was suitable for the release of electrolytes from multiple emulsions. [on SciFinder(R)]

Rabbit marrow cells inoculated into diffusion chambers (10(7) cells/chamber) were implanted intraperitoneally into athymic mouse hosts and cultured in vivo for 20 days. A connective tissue consisting of bone, cartilage and fibrous tissues is formed by the stromal fibroblastic cells of marrow within the chambers. Cell kinetics and tissue differentiation have been studied using histomorphometric and biochemical analyses. Haemopoietic cell numbers decrease to less than 0.05% of the initial inoculum during the 20-day period. At 3 days an average of 15 stromal fibroblastic cells only are identifiable within the chambers. After 3 days there is a high rate of stromal cell proliferation with a doubling time of 14.5 h during the period from 3 to 8 days and an increase in the total stromal cell population by more than six orders of magnitude from 3 to 20 days. Thirteen to fourteen population doublings occur before expression of the first observable differentiation parameter, alkaline phosphatase activity. The data demonstrate that the mixture of connective tissues formed within the chamber is generated by a small number of cells with high capacity for proliferation and differentiation. This is consistent with the current hypothesis that stromal stem cells are present in bone marrow.

The interaction of Sendai virus glycoproteins with cell membranes was proposed to increase the lateral mobility of membrane proteins, enabling membrane fusion and the aggregation of intramembrane particles by thermotropic separation (Volsky, DJ & Loyter, A, Biochim biophys acta 514 (1978) 213 [13]; Maeda, T et al. Exp cell res 123 (1979) 333 [15]; and Kim, J & Okada, Y, Exp cell res 132 (1981) 125 [44]). In order to test this hypothesis, we employed fluorescence photobleaching recovery to investigate the effects of Sendai virus-induced fusion on the lateral mobility of membrane proteins and lipids in a variety of cell types (human erythrocytes, BHK21, HeLa, 3T3 NIH, and mouse spleen lymphocytes). The results of the lateral diffusion measurements demonstrate that no significant alterations occur in the lateral motion of membrane proteins or a fluorescent phospholipid on all the cell types examined, including cells which revealed high susceptibility to the virally mediated fusion (human erythrocytes and BHK21 cells). These findings suggest that a permanent increase in the lateral mobility of cell surface components does not generally occur during Sendai virus-induced cell fusion, and thus cannot play a role in the fusion mechanism. The possible involvement of transient alterations in the lateral mobility of membrane components in the fusion mechanism is discussed.