title: Studies with an improved white cell isolation method to assess the vitamin C status in surveys.
abstract: A method for isolating white cell which employs a disposable syringe has been modified and adapted to nutrition survey work. Methylcellulose was used as a clumping agent for erythrocytes. This method was more rapid and was easier to perform than a previously recommended metrizoic acid technique which gave similar results. Average leucocyte recovery was 62% and erythrocyte contamination was 0.75 erythrocyte per leucocyte. Recovery of added ascorbic acid to white cell pellets was better than 95% and tests of the reproducibility of the assay gave a coefficient of variation of 6% for samples in the deficient range. Extraction of vitamin C from white cells was carried out in a centrifuge tube and took only 30 sec. Vitamin C was found to be stable for several weeks after freezing either the white cell extracts in dilute metaphosphoric acid or simply the white cell pellets. The method was utilized under field conditions during a small survey of Eskimos from Arctic Bay. The significance of the white cell vitamin C content as an index of nutritional status is discussed.
mesh_terms: D001205:Ascorbic Acid / Q000097:blood*; D002469:Cell Separation / Q000379:methods*; D002482:Cellulose; D004492:Edetic Acid; D006801:Humans; D007202:Indicators and Reagents; D007958:Leukocyte Count; D007962:Leukocytes / Q000032:analysis*; D009749:Nutrition Surveys; D010070:Oxalates; D010783:Photometry
chemical_list: D007202:Indicators and Reagents; D010070:Oxalates; D002482:Cellulose; D004492:Edetic Acid; D001205:Ascorbic Acid