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Drug Monitoring and Toxicology |
1 Environmental Health Sciences, Department of Public Health Sciences, and 2 Division of Medical Oncology, Department of Oncology, Cross Cancer Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
aAddress correspondence to this author at: Environmental Health Sciences, Department of Public Health Sciences, Faculty of Medicine and Dentistry, University of Alberta, 10-102 Clinical Sciences Bldg., Edmonton, AB, Canada T6G 2G3. Fax 780-492-7800; e-mail xingfang.li{at}ualberta.ca.
Background: Mass spectrometric (MS) detection of intact hemoglobin (Hb) adducts presents considerable analytical challenges because of the noncovalent association of the 4 subunits of Hb, and MS characterization of the interaction of intact Hb with platinum drugs has not been reported. We developed a technique for detecting intact Hb and its drug adduct and studied the interactions between intact Hb and oxaliplatin.
Methods: We incubated a series of mixtures of Hb and oxaliplatin at 37 °C for 24 h or 5 days to investigate adduct formation. Blood samples from colorectal cancer patients undergoing oxaliplatin treatment were analyzed for novel adducts of intact Hboxaliplatin, which were characterized with nanoelectrospray ionization quadrupole time-of-flight MS.
Results: Two intact Hb adducts, one with the whole oxaliplatin molecule and the other with oxaliplatin losing the oxalate ligand, were identified. Analysis of erythrocytes from the cancer patients provided direct evidence that oxaliplatin accumulated as Hb adducts in erythrocytes. A higher fraction (
70%) of Hb was bound to oxaliplatin in erythrocytes from a patient who could not tolerate oxaliplatin treatment than in erythrocytes from another patient who benefited from this treatment.
Conclusions: The nanoelectrospray tandem MS technique enabled determination of the intact Hb tetramer and its association with oxaliplatin. Hboxaliplatin adducts in erythrocytes may serve as a clinical biomarker for toxic response and treatment efficacy.
The following articles in journals at HighWire Press have cited this article:
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P. Kleinert, M. Schmid, K. Zurbriggen, O. Speer, M. Schmugge, B. Roschitzki, S. S. Durka, U. Leopold, T. Kuster, C. W. Heizmann, et al. Mass Spectrometry: A Tool for Enhanced Detection of Hemoglobin Variants Clin. Chem., January 1, 2008; 54(1): 69 - 76. [Abstract] [Full Text] [PDF] |
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