Quantitative studies of blood and bone marrow neutrophils in normal mice

Abstract

A method for determining the total number of nucleated cells in the marrow cavity of the humerus of a mouse is described. This technic proved to be reasonably accurate. The humerus contained an average of 7.15 x 106 nucleated cells which constituted 2.8% of the total cells in the entire marrow as judged by distribution of radioactive Fe in the skeleton. This technic, when coupled with a determination of the percentage of cells which stain for peroxidase, provides a fairly rapid and simple means of determining total marrow neutrophils. No difference was observed in leukocyte concentration in venous blood samples obtained from the orbital sinus, vena cava, or tail when properly controlled comparisons were made. However, leukocyte concentration in blood samples from the aorta was less than one-half that in venous samples. All of the following factors were found to influence the leukocyte concentration in venous blood samples: repeated sampling, ether or pentobarbital anesthesia, heparin administration, time of day, and heating the tail.