title: Employment of synchronized cells and flow microfluorometry in investigations on the JB-1 ascites tumour chalones.
abstract: In most experimental ascites tumours the growth rate decreases with increasing age and cell number. This decrease is caused by a prolongation of the cell cycle and an increasing accumulation of non-cycling cells in resting (or quiescent) G1 and G2 compartments. In cell-free ascitic fluid from the JB-1 ascites tumour in the plateau phase of growth lowmolecular-weight substances have been found which reversibly and specifically arrest JB-1 cells in G1 and G2. The present paper describes an in-vitro model for testing the effect of the humoral growth inhibitors contained in the ascitic fluid. The test system is based on synchronized JB-1 cells analysed by flow-through cytofluorometry. Addition to the synchronous cells of a ultrafiltrate (less than 50000 Daltons) of the JB-1 ascitic fluid was found to induce a complete, but temporary arrest of the cells at the G1-S border.
mesh_terms: D000818:Animals; D001202:Ascitic Fluid; D002455:Cell Division; D005470:Fluorometry; D006131:Growth Inhibitors / Q000032:analysis*; D051379:Mice; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental; D010954:Plasmacytoma / Q000032:analysis*; D013997:Time Factors; D014182:Transplantation, Autologous
chemical_list: D006131:Growth Inhibitors