The long term objectives are to develop reliable methods for the assessment of selenium (Se) status in humans that can be used to determine whether there is any relationship between Se status and certain metabolic disorders such as cancer. The approaches are to determine the influence of different levels of Se intake, the effects of dietary chemical forms of Se and the influence of esphageal or stomach cancer on the relative distribution of erythrocyte Se between glutathione peroxidase (GPx) and hemoglobin (Eb), on the distribution of Se between different molecular weight (MW) plasma proteins, and on the percentage of urinary Se as the trimethly selenonium (TMSe) ion. Populaitons deficient in Se (0.003 to 0.022 mg/day), with normal Se intake (0.24 to 1.5 mg/day) and with high Se intakes exhibiting chronic selenosis (3.2 to 6.7 mg/day) have been identified in China. Blood and urine samples will be taken from 10 men living in each of these 4 areas of China, and from 20 men living in each of the states of South Dakota and Oregon of the United States. Men living in the Keshan disease area (Se deficient) of China will be supplemented with 200 mg Se daily as either selenate or seleno- methioine, and blood and urine collected at bimonthly intervals for 1 year. The erythrocyte lysate and plasma will be subjected to gel filtration. The distribution of Se and GPx activity between the different MW proteins in plasma and erythrocyute lysates will be determined based on the eluted patterns from the columns. It is planned to determine Se levels either by a flurormetric procedure or an atomic absorption method using a Zeeman background corrector, and GPx activity by a coupled enzyme procedure. TMSe content in urine will be determined by a high pressure liquid chromatographic procedure, and from the total Se content the percentage as TMSe calculated. Correlation coefficients will be calculated for whole blood Se content and GPx activity in erythorocyte lysates, the individual erythrocyte GPx and Eb peaks (both Se and PGx), plasma Se and GPx, the individual plasma Se and GPx peask, total urinary Se content, and the percentage of urinary Se as TMSe. The t-test will be used to determine any significant differences in any blood or urine component between men with or without esphageal or stomach cancer.
Showing the most recent 10 out of 15 publications
