Structural isomerism of Ru(ii)-carbonyl complexes: synthesis, characterization and their antitrypanosomal activities

New complexes with the formula [RuCl(CO)(dppb)(N–N)]PF₆ were prepared by varying the CO position as well as the diimine ligand.

The role of the spleen in the repopulation of the haemopoietic system of heavily-irradiated mice

The respective role of the spleen or of the bone marrow in the regeneration of the haemopoietic progenitor compartment of heavily-irradiated mice has been investigated. Splenectomy was used to this end in animals injected with exogenous isogenic cells or regenerating from endogenous spleen or marrow cells. Analysis of the data as a function of time shows that the presence of the spleen affects marrow CFU repopulation only at the early post-irradiation stages. The expansion of the marrow progenitor pool proceeds, however, rather independently of the spleen and marrow CFU remain eventually as the main source of haemopoietic cells in the surviving mice. Thus the reaction of the spleen may be envisaged as a fast, important but transient contribution to the overall haemopoietic function of heavily-irradiated animals.

Studies on the haemopoietic stem cells of mouse foetal liver

Cells obtained from the blood-forming organs of donor animals and injected, under appropriate conditions, into heavily irradiated mice, can colonize, among other organs, the spleen of the hosts, giving rise to discrete and differentiated nodules of haemopoietic tissue (Till & McCulloch, 1961). It has been demonstrated that the number of nodules is directly proportional to the number of injected cells and that such nodules may be regarded as clones arising from single cells (Till & McCulloch, 1961; Becker, McCulloch & Till, 1963). The postulate of classical haematological theories (Maximov & Bloom, 1934; Ferrata, 1935) that a proportion of the cells in blood-forming organs is capable of indefinite division with renewal of the stem line and of differentiation into mature blood cells has thus been experimentally demonstrated.

Whether colony-forming cells should actually be regarded as the very primitive stem cells of the haemopoietic tissues (McCulloch, 1963; Lewis & Trobaugh, 1964) or as the earliest step of a differentiative haemopoietic line (Kay & Davies, 1964) has not yet been fully agreed upon.