Cultured mouse bone marrow and human blood cells were labelled with 3H‐thymidine, smeared, and stained, using peroxydase reagents or the May‐Grünwald Giemsa procedure. The slides were dipped in a ˜ 12% solution of polyvinylchloride, bleached by a photographic fixer and processed for liquid emulsion radioautography. This method yielded technically very satisfactory radioautographs of pre‐stained smears.

The effect on haematopoietic progenitor cells of specific antisera against mature haemic cells has been investigated.Heterologous anti-lymphocyte and anti-granulocyte sera were prepared by injecting suspensions of rat target cells into rabbits. Recirculating lymphocytes were obtained from thoracic duct lymph, non-recirculating ones from blood of rats in Experimental Medicine, 134, 815. TRENTIN, J.J. & JUDD, K.P. (1973) Prevention of acute graft-versus-host (GVH) mortality with spleenabsorbed antithymocyte globulin (ATG). Transplantation Proceedings, 5, 865.

No abstract

We applied the radioactive microsphere method to follow the magnitude and time course (0 to 96 hours) of blood flow changes during development and recovery from anemia in awake rats. Blood flow was also monitored during a 96-hour period after polycythemia was induced (erythropoietin administered subcutaneously [SC]). The possible influence of innervation was also examined. After a blood loss of approximately 50% (hypovolemia), blood flow to the femoral marrow tripled within 12 hours and remained elevated for the entire 96-hour period. The relative increase in blood flow to the femoral bone was even greater. Similar findings were obtained in rats with phenylhydrazine (PHZ) hemolytic anemia (normovolemia). Denervation had no detectable effect on the increased blood flow to either marrow or bone. The augmented blood flow during hemolytic anemia was accompanied by a doubling of the oxygen consumption rate by the marrow, while the glucose uptake was not detectably altered. Erythropoietin supplements (3 x 1,000 IU/kg, SC, 6-hour intervals) increased blood flow to the marrow by approximately 25% after 48 hours, and at 72 hours the blood flow had reached a value twice that obtained under control conditions. These results indicate that blood flow to bone marrow is highly variable and hormonally and/or locally regulated. This may have practical consequences for marrow transplantation technology and for administration of drug therapy to patients with insufficient bone marrow hematopoiesis.