FABMS/MS OF CNS PHOSPHOLIPIDS IN CHILDREN WITH CANCER

The purpose of the proposed study is to develop a method based on fast
atom bombardment mass spectrometry and tandem mass spectrometry
(FABMS/MS) for measuring cell membrane damage in the central nervous
system (CNS). This damage is the result of whole brain radiation (WB
RTX) and intrathecal methotrexate (IT MTX) used in the treatment of
children with acute lymphoblastic leukemia (ALL) and medulloblastoma.
The proposed FABMS/MS method will be used in combination with normal
phase high performance liquid chromatography (HPLC). The specific aims
of the proposed study are: 1. The identification of the phospholipid classes and species in
cerebrospinal fluid (CSF) collected from children with ALL and
medulloblastoma before and during CNS treatment. Samples will be
fractionated using normal phase HPLC and analyzed off line using FABMS
and FABMS/MS techniques. 2. Identification of phospholipid markers of CNS membrane damage
following WB RTX and IT MTX treatment by FABMS/MS in combination with
HPLC. 3. Quantitation of phospholipid markers of CNS membrane damage by fast
atom bombardment mass spectrometry (FABMS) and HPLC. 4. Explore the possibility of using FABMS/MS alone to identify and
quantify the cell membrane damage by analysis of total CSF lipid
extracts. A repeated measures comparative three group design will be used.
Subjects will be grouped by type of CNS treatment: (Group I:IT MTX only;
Group II:IT MTX, ARA-C and hydrocortisone; Group III: WB RTX). Total CSF
lipid extracts from children before, during and after WB RTX and IT MTX
will be analyzed to completely characterize the phospholipid classes and
molecular species present, and to identify. markers of CNS cell membrane
damage. Quantitation of the markers will be done using calibration
curves (HPLC) and internal standards (FABMS). Changes over time will be
calculated by repeated measures analysis of variance. Direct analysis of
total CSF lipid extracts will be done using (+) and FABMS/MS techniques. The results of this research will provide important information on the
mechanism of membrane damage during WB RTX and IT MTX. Identification of
phospholipid markers of membrane damage will provide a method of
fundamental clinical importance for monitoring the CNS toxicity of
therapy in diverse patient populations to minimize the long-term adverse
effects.