Significance of transmission electron microscopy in subtyping of monocytic leukemia.

The objective of this paper is to produce an ultrastructural classification of acute monocytic leukemia (AML-M5) in relation to clinical behaviors. The ultrastructural characteristics of blasts of the monocytic series were analyzed in 72 M5 patients by transmission electron microscopy (TEM), in terms of their content of typical monoblasts, atypical monoblasts, atypical promonocytes, and typical promonocytes in bone-marrow aspirates. Four kinds of monocytic blasts were identified by cell size and shape, nuclear profile, nucleocytoplasmic ratio, heterochromatin content, nucleolus, granules, vesicles, and Golgi apparatus. Their characteristics of remission rate, cytochemistry, immunophenotype, and cytogenetics were also investigated. The data obtained permitted M5 patients to be divided into monoblast and promonocyte types. Monoblast-type patients expressed weaker monocytic enzymograms and specific antigen staining for CD14 and CD64, compared with promonocyte-type patients. Monoblast patients had higher CR than promonocyte patients. Therefore, TEM subclassification of patients differs from and improves upon the light microscopical criteria for distinguishing monoblasts and promonocytes and has clinical significance.

[Ultrastructural analysis of 5' nucleotides distribution in acute myeloid leukemia subtypes].

5' nucleotides (5'NT), a purine degradative enzyme, is capable of hydrolyzing nucleotide and acting as a phosphotransferase simultaneously. It has critical role in maintaining nucleotide metabolism balance. The present study was aimed to investigate the expression of 5'NT in bone marrow granulocytes (BMGs) from patients with acute myeloid leukemia (AML) and healthy donors comparatively. The BMGs were isolated from bone marrow of 33 patients with AML and 6 healthy donors by using lymphocyte isolating solution. The reactivity of 5'NT was detected by electron microscope and cytochemistry of cytidine monophosphate (CMP). The positive BMG ratio and their index were calculated on the base of ultrastructural observation semiquantitatively. The results indicated that electron microscopy revealed plasma membrane reacting pattern of CMP. Most BMGs from normal donors were CMP negative or exhibited lower active degree. All cases of M(0), M(1), M(2) and t (8; 21) showed high positive percentages and high indexes of BMGs, but no statistic differences between them. APL of t (15; 17) shared lower percentages and indexes than other subtypes. There was no significant difference between APL and normal donors statistically. In conclusions, the results suggested the expression of 5'NT may be associated with BMG differentiation in AML, and APL of t (15; 17) may be a highly differentiated leukemia subtype.