ABSTRACT
Serum uric acid, red cell SOD and catalase activities were determined in 117 patients acute lymphoblastic leukaemia, chronic myelocytic leukaemia, Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, polycythemia vera and multiple myeloma in comparison to 40 healthy normal subjects. About 6-40 percent of these patients had serum uric acid level over 7 mg/dl. Altogether, 14 patients had hyperuricaemia, therefore they were grouped together. There was a reverse relationship between serum uric acid level and SOD activity in these patients. The hyperuricaemia is a result of increased proliferation and destruction of tumour cells which stimulates the generation of superoxide radicals. Therefore, red cell SOD will be decreased in patients with hyperuricaemia. In order to compensate for an elevated oxidant stress, SOD will therefore increase. These findings could explain the variable results of red cell SOD reported earlier in patients with malignancy of haematological origin. There was no relationship between serum uric acid and red cell catalase activity in these patients.
ABSTRACT
Many previous studies on superoxide dismutase (SOD) and catalase activities in red cells of patients with malignant lymphoma showed results. One possible factor may be the different oxidant stress in these patients. The objective of the present study was determine SOD and catalase activities in red cells of patients with untreated malignant lymphoma who had normal serum uric acid level. The studies were performed on 19 patients with Hodgkin's disease and 34 with non-Hodgkin's lymphoma (NHL) in comparison to 40 healthy normal subjects. The mean values of erythrocyte SOD activity in these patients were not significantly different from that of normal subjects. Serum uric acid levels were also within the normal ranges and only 4 out of 53 patients had serum uric acid over 7 mg/dl. There was no relationship between serum uric acid level would have red cell SOD within the normal limits. As hyperuricaemia may occur as a result of increased purine turnover from the increased destruction of tumor cells by therapy. The overproduction of uric acid would stimulate the generation of superoxide radicals. In such cases, red cell SOD would therefore be decreased during the hyperuicaemia. These findings may therefore explain why some previous authors found either increased or decreased SOD activity in red cell of patients with malignant lymphoma. No significant differentce of erythrocyte catalase activity between the groups of patients and the normal group was demonstrated in the present study.