PRIOR CONCURRENT THERAPY: Biologic therapy: At least 1 month since prior platelet or red blood cell transfusions Chemotherapy: At least 6 weeks since nitrosoureas or mitomycin At least 4 weeks since other chemotherapy No investigational or standard chemotherapy for at least 2 months after completion of last dose of UCN-01 Endocrine therapy: Not specified Radiotherapy: At least 4 weeks since radiotherapy Surgery: At least 4 weeks since major surgery Other: No concurrent anticonvulsant medications