One month old C57 male black mouse was perfused with Ringer's solution for 2 minutes followed by 2% glutaraldehyde and 2% paraformaldehyde in 0.15M sodium cacodylate buffer, pH 7.4, at 35 degrees Celsius for 10 minutes. Tissue was removed and fixed on ice for 1-2 hours. During this time the tissue was further dissected. Dissection was followed with washes (5x5 minutes in cold 0.15M sodium cacodylate buffer), and postfixation (1% OsO4 in 0.15M sodium cacodylate buffer on ice for 1 hour), another series of rinses in cold ddH2O 4x5 minutes then 2% uranyl acetate in ddH2O on ice for 2 hours. After staining, tissue was rinsed, dehydrated and embedded in durcupan ACM resin using standard embedding procedures.