THE ASSAY OF THE TRANSPLANTATION POTENTIAL OF FRESH AND STORED BONE MARROW BY TWO <i>IN VIVO</i> SYSTEMS*.

Abstract

Recent years have witnessed refinements in marrow-storage procedures, developed in the hope of evolving a technique capable of preserving the repopulating potential of marrow, the only function of value in marrow grafting.This specific attribute has been referred to as "marrow viability."There exist a number of in-vitro techniques reported capable of differentiating live cells from dead cells.These techniques have been applied to marrow suspensions, and the results have been assumed to express the repopulating potential of the marrow.From these studies have evolved the current concept of the value of stored marrow and of marrow stored by one procedure as compared to another.We have attempted to compare the results of these in-vitro techniques to the transplantation of fresh and thawed marrow as assayed by (1) the protective effect of the marrow in lethally irradiated mice, and (2) the ability of mouse marrow to repopulate hematopoietic depleted mouse spleens.The results of these two in-vivo assay systems are reported in this paper.The in-vitro studies correlating with them will be reported later. Mouse-Survival StudiesThe most direct estimate of the transplantation value of a marrow suspension is the estimate of its protective quality when injected into lethally irradiated animals.If it were possible to determine accurately the 50 per cent protective dose in the lethally irradiated animal for both thawed and fresh cells, a correspondingly accurate estimate of the protective quality of thawed to fresh marrow could be made.Such studies with fresh marrow, however, have yielded widely varying results, and the I'Dbo for various strains of mice has varied from 80,000 to well over 1,000,000 cells.'-3