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The effect of bryostatin and GM-CSF on leukemic blasts from a patient with M1 AML. Although neither agent alone had much of an effect, the combination induced morphological evidence of myeloid differentiation with a decrease in the nuclear-cytoplasmic ratio, nuclear condensation with the loss of nucleoli, and the appearance of cytoplasmic granulation and vacuoles combination. For datails, see the article by Matsui et al., in this issue.