Detection and analyses of ascorbyl radical in cerebrospinal fluid and serum of acute lymphoblastic leukemia.

We have detected and analyzed a free radical in human cerebrospinal fluid (CSF) of acute lymphoblastic leukemia (ALL) for the first time using electron paramagnetic resonance (EPR) at ambient temperature. We have also introduced an alternative capillary method to measure the radical. EPR spectra of the radical show a characteristic doublet with hyperfine coupling value of 1.8 G and g = 2.005. Based on EPR measurements, computer simulation, and literature values, we have determined that the species is ascorbyl radical (AsR). The radical has been investigated in CSF samples from ALL patients having no therapy, undergoing chemotherapy, and following therapy. Determination of the ascorbyl radical concentrations in CSF and serum was attempted using known concentrations of a nitroxyl radical. In addition, comparison in CSF and serum for ALL has been made along with statistical analyses of the data obtained. We found that AsR in CSF and serum has a strong correlation in patients undergoing chemotherapy (n = 57, r = 0.57, P < 0.0001). Ascorbate in CSF and serum show good correlation in patients having therapy but not for patients after therapy.