Packing of human erythrocytes in a centrifugal field

The rate of packing of human erythrocytes in whole blood and washed ones in aqueous suspension was investigated in a centrifugal field of 250 g. The Voigt-Kelvin rheological model was found to be well suited to describe the packing process. The ratio of the elastic modulus to viscosity was evaluated from this model. Its value suggests that the flexibility of the cell plays a minor role compared to other viscosity factors. Also the model suggests that the rate of packing is a complicated function of various viscoelastic factors. Empirical parameters describing the rate of packing are sensitive to drastic changes in cell flexibility, such as caused by formaldehyde treatment, whereas no fluidizing effect of procaine on cell membrane was detected. The rate of packing is not affected by decreasing the pH from 7.4 to 6.5. The method of mild centrifugation could be of some use for rapid evaluation of substantial flexibility changes in washed blood cells.     

Increased autophagocytosis induced by colchicine in rat sympathetic neurons

The effect of colchicine was followed up in the superior cervical ganglion of rats. An increase was observed in the number of autophagocytosis vacuoles in the neurons, especially three and four hours after the intraperitoneal injection of colchicine (0.05 mg/100 g.b.w.). These vacuoles presented very various ultrastructural characters due to their different content and stage of degradation. Their high number is explained by the action of colchicine upon cytoplasmic microtubules, the secondary inhibition of the intracellular movement, and the blockage or reduction of the fusion of primary lysosomes with the autophagic vacuoles, which are continuously formed in the neuron cytoplasms, as well as in other cells.