The purpose of the study is to combine Urodilatin (ANP analogue), which will increase glomerular filtration rate (GFR), and mannitol, which will increase the rate of urinary flow and solute excretion. We intend to treat twenty consecutive allogeneic bone marrow transplant patients in a phase II study comparing results with historical controls.

We hypothesize that the incidence of renal dysfunction, ARF and thus mortality in allogeneic bone marrow transplantation can be significantly reduced by the use of protective agents Urodilatin and mannitol. We feel that this combination is best administered prior to and during the first two weeks of treatment when patients encounter immunosuppressive agents and the onset of early transplantation complications.

Inclusion Criteria:

• Age 18-65 years
• Presence of malignancy or hematological disease whose treatment will be allogeneic stem cell transplant and high-dose conditioning therapy.
• Adequate baseline evaluation: adequate renal function (creatinine clearance > 60 ml/min); Adequate hepatic function (SGOT, SGPT, bilirubin and alkaline phosphatase < 1.5 times normal); adequate cardiac function (MUGA showing a left ventricular ejection at rest > 45%); adequate pulmonary function (DCLO > 60%).

Exclusion Criteria:

• Known hypersensitivity to ANP or mannitol
• Congestive heart failure
• Previous bone marrow transplant
• BP less than 90 mm systolic or less than 60 mm Hg diastolic