STAINING AND MORPHOLOGIC FEATURES OF BONE-MARROW HEMATOPOIETIC-CELLS IN DESERT TORTOISES (GOPHERUS-AGASSIZII)

Objectives-To determine optimal site for collection of bane marrow fro m desert tortoises, and to characterize cytologic staining and morphol ogic features of bone marraw hematopoietic cells. Animals-16 desert to rtoises. Procedure-Bone marrow was obtained at necropsy from the pelvi s, proximal portion of the humerus, femur, and thickened portions of t he cranial to craniolateral and caudal to caudolateral margins of the carapace and plastron for histologic and cytologic examinations. Cytoc entrifuged preparations of marrow cells were evaluated for reactivity to cytochemical stains. Results-Histologic sections were adequate for evaluating acidophils, acidophil precursors, and erythrocyte precursor s, it was difficult to differentiate among monocytes, lymphocytes, thr ombocytes, and blast cells, and eosinophils could not be differentiate d from heterophils, Basophils were in rare, smart clusters of 3 to 12 cells. A few lymphoid follicles were found in the pelvis and long bone s. Use of cytochemical staining accomplished differentiation between a granular heterophil precursors and granulated heterophils, and between granulated eosinophils and basophils. Monocytes, azurophils, and mono blasts had similar staining features. Staining of erythrocyte precurso rs with Sudan black B differentiated them from lymphocytes. Only a few small cells with periodic acid-Schiff-positive cytoplasm were identif ied as thrombocytes. Lymphocytes did not stain with any of the cytoche mical stains. Conclusions-For histologic and cytologic evaluation of b one marrow hematopoietic cells, pelvis, proximal portion of the humeru s, femur, and thickened portions of the peripheral cranial and caudal regions of the carapace and plastron are suitable sites to collect spe cimens. There are distinct cytochemical markers for heterophil, monocy te, and erythrocyte precursors, as well as later stage heterophils, eo sinophils, basophils, monocytes, and azurophils.