Use of ascorbic acid in the 51Cr labelling of mouse fibrosarcoma cells.

We have studied and discussed the significance of the use of ascorbic acid in 51Cr labelling of cells. The following two advantages seem credible if cells (mouse fibrosarcoma) in culture are incubated for about 2 h in a medium containing Na2 51CrO4 and then ascorbic acid is added to the medium and incubation continued for ten more minutes: (a) the natural intracellular conversion of Cr6+ to Cr3+ appears to be aided, (b) the incorporation of chromium by cells is higher.

Cytotoxicity of subpopulations of splenic cells from normal and fibrosarcoma - bearing mice towards syngeneic tumour cells.

The nonadherent splenic cells from normal and tumour-bearing (mouse fibrosarcoma-MFS) Swiss mice were divided into 6 subpopulations on Percoll step density gradient and characterised. For the determination of their cytotoxicity towards syngeneic MFS cells and their electrophoretic mobility (EPM), the splenic cell populations were pooled to form 2 broad groups: a lower-density group (density of saline to just less than 1.069 g/ml) and a higher-density group (1.069 to just less than 1.087 gm/ml). In general, the splenic cells from mice bearing 10- to 11-day-old MFS tumours differed in certain characteristics from those of normal mice in that they showed an increase in the following: proliferation, heterogeneity, with appearance of large cells (greater than 70 mu2); cells with a lower density (less than 1.069 g/ml); cells with a lower (less than 0.85 micron/sec/Volt/cm) anodi cEPM. The cytotoxicity studies revealed that: a) the lower-density splenic cells of both normal and tumour-bearing mice were more cytotoxic than the higher-density splenic cells; b) the lower- and higher-density splenic cells of tumour-bearing mice were more cytotoxic than the corresponding cells of normal mice. These findings indicate that the splenic cells of mice with a lower EPM and a lower density are the main contributors of cell-mediated cytolysis of a subpopulation of MFS cells.

Radiobiological effect of heparin in Swiss mice, human amnion cells and E. coli B/r irradiated with Co60 gamma-rays.

The radiobiological action of Heparin was investigated using the test systems E. Coli B/r, Human Amnion (HA) cells and Swiss mice. The Heparin treatment of these systems effected following changes in their response towards irradiation with Co60 gamma-rays: (a) more sensitization of E. coli B/r in hypoxic than in oxic condition, (b) no significant modification for HA cells in oxic condition but their sensitization under hypoxia, (c) larger recovery of anodic electrophoretic mobility of irradiated HA cells, (d) increased life span and smaller reduction in the splenic and thymus weights of irradiated Swiss mice. It seems, therefore, that Heparin, a natural molecule of animal world, possesses the potentiality to modify radiation response of living systems and may find useful application in radiation therapy.