OBJECTIVES: I. Estimate the lowest dose of deoxycytidine (dC) that can be given as a host protective agent in conjunction with high dose cytarabine (HD ARA-C) in patients with refractory acute myelogenous leukemia or other hematologic malignancies. II. Determine the maximum tolerated dose and dose-limiting toxic effects of HD ARA-C/dC in these patients. III. Characterize the pharmacokinetics of continuously administered HD ARA-C/dC in these patients. IV. Characterize, when possible, the pharmacodynamics of HD ARA-C, dC, and their metabolites in blasts obtained from leukemic patients participating in this trial. V. Recommend the lowest possible dose of dC that can be given in combination with HD ARA-C in future phase II trials.