Marrow erythroid and neutrophil cellularity in the dog.

Abstract

A B S T R A C T This paper describes a method for determining the number of marrow erythroid and neutrophil cells in which the cellularity of marrow sections was related to that of the total marrow by radioiron dilution. Tissue sections were prepared from methacrylateembedded dog marrow biopsies, and neutrophils were identified by staining of their primary granules. After correction of direct section counts for multiple counting error, accurate neutrophil-erythroid ratios were established with a coefficient of variation of less than 10% when 104 cells were examined. An average neutrophil-erythroid ratio of 1.2 was found in six normal dogs.The total number of nucleated red cells in the dog was 5.48±0.78 X 109/kg (+1 SD), and the corresponding erythron iron turnover was 0.90±0.11 mg Fe/100 ml whole blood/day. The total number of marrow neutrophils, derived from the neutrophil-erythroid ratio, was 6.6±0.59 X 109 cells/kg, of which 1.4 were promyelocytes and mvelocytes, 2.3 were metamyelocytes and bands, and 3.0 were segmented neutrophils. Leukopheresis studies were carried out in six dogs to confirm the accuracy of these cellular measurements. 1\Iarrow counts showed a mean decrease of 22.7 X 109 cells or 35% of the postmitotic neutrophil pool, and it was calculated that 10.2 x 109 additional cells had been taken from already circulating blood. This estimated deficit of 32.9 X 109 was almost identical to the 33 X

Neutrophil kinetics in the dog.

“…1 a and Table II. The mean EIT of 0.86±0.14 mg Fe/100 ml whole blood/day was similar to that measured in previous studies of normal animals in which the turnover was 0.90±0.11 (5). The number of NRBC was calculated to be 5.36+0.84 X 109 cells/kg.…”

“…However, these latter studies have been of limited usefulness because of the inadequate methods available for measuring marrow cellularity. In an accompanying paper, a method for determining the number of erythroid and neutrophilic cells in dog marrow has been described (5). In the present paper this measurement of marrow postmitotic neutrophils (PMIN) is coupled wvith the measurement by ['H]thymidine of neutrophil marrow transit time (AITT) to determine total neutrophil production.…”

“…Methodology involved in determining the number of marrow neutrophils includes the ferrokinetic measurement of the nucleated red cell (NRBC) mass (5), and the measurement of the PMN/ erythroid ratio (PMN/E) in bone marrow sections. From these two determinations the marrow neutrophil mass is calculated.…”

“…(1) 0.90 ) where 5.48 X 109 represents the number of NRBC per kilogram in normal dogs and 0.90 represents the mean basal EIT in mg Fe/100 ml whole blood/day (5).…”

“…A bone marrow biopsy obtained from the posterior iliac crest with an electrical drill was fixed in formalin and embedded in methacrylate as previously described (5). Sections 3 ,um in thickness were stained with naphthol-ASD chloroacetate esterase to permit identification of primary granules of the neutrophils and was counterstained with 1% toluidine blue.…”