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RESEARCH PRODUCT

Clearance of Ascorbic Acid in Plasma in Patients Before Major Maxillofacial Surgery Compared With That in Volunteers

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Reduced concentration of ascorbic acid (AA) in plasma is often observed in tumor patients. Besides malnutrition, an increased AA consumption in tumor patients is discussed as a main reason for reduced AA concentration in plasma. A reduced AA concentration caused by malnutrition would not influence the total clearance (Cltot) of AA in plasma; however, a change in AA consumption would alter the Cltot. To investigate this further, a study was carried out on 20 patients hospitalized for major maxillofacial surgery and 20 volunteers. The Cltot of AA in plasma after bolus injection of AA (4 mg/kg body wt) in tumor patients was compared with that in volunteers. AA concentration in plasma (P0.05) was significantly lower in tumor patients (median and 25th and 75th percentiles: 23.7, 14.6, and 32.7 mumol/l) than in volunteers (median and 25th and 75th percentiles: 66.5, 59.6, and 78.6 mumol/l). No significant change in Cltot was observed for tumor patients (median and 25th and 75th percentiles: 11.5, 8.0, and 14.0 l/h) compared with volunteers (median and 25th and 75th percentiles: 11.3, 9.9, and 13.2 l/h). No indication of an increased consumption of AA in tumor patients could be detected. The lowered concentration of AA in plasma observed in our patients might be the result of a reduced AA intake.