Tissue samples were placed into propylene oxide for
2/15 min, and then they were placed in 1:1 mixture of
propylene oxide/araldite for 1 h and 1:2 mixture
propylene oxide/araldite, respectively. Samples were
than embedded into pure araldite and kept overnight at
room temperature. Polimerization is made at 60 8C for
48 h. Thick sections were stained with toluidine blue
(Fig. 1). Ultrathin sections were stained for 1 h with 2%
uranile acetate/lead citrate. Observation was made log
using JEOL 1220 electron microscope at 80 kV.