The paper strips were subjected to centrifugal elution to obtain total proteins present in the FGC. To do this, incubated for 30 minutes in 100 .mu.l of elution buffer containing 0.05% Tween in Tris-HCl pH 7.4 (Fluka, Sigma-Aldrich Chemie GmbH, Buchs, Switzerland) and then centrifugarnn 10,000 xg for 5 minutes at 4 ° C. The process of centrifugal circumvention repetio 3 times to a final volume of 300 ul, which was stored at -80 ° C until analysis.