Avidin fluorescein

Cryostat sections were obtained from bowel specimens perfused with O.C.T. compound and snap frozen. After warming the slide to 27 °C, the sections were fixed for 10 min (2% paraformaldehyde and PBS at pH 7.43). The slides were washed with buffer (PBS, 5% sheep serum, 0.1% azide, 1 mM MgCl₂, 1 mM CaCl₂) and blocked with 20% sheep serum in PBS. The slides were treated with the biotinylated lectin followed by avidin-fluorescein (Southern Biotech, Birmingham, AL, USA) or avidin-fluorescein alone control. The slides were incubated for 1 h at 27 °C, washed 3 times, and mounted with DAPI-containing medium (Vector Labs, Burlingame, CA, USA). The tissue sections were imaged with a Nikon Eclipse TE2000 inverted epifluorescence microscope (Tokyo, Japan).

Cryostat sections were obtained from lung specimens perfused with O.C.T. compound and snap frozen. After warming the slide to 27°C, the sections were fixed for 10 minutes (2% paraformaldehyde and PBS at pH 7.43). The slides were washed with buffer (PBS, 5% sheep serum, 0.1% azide, 1mM MgCl₂, 1mM CaCl₂) and blocked with 20% sheep serum in PBS. The slides were treated with the lectin followed by avidin-fluorescein ((Southern Biotech, Birmingham, AL, USA) or avidin-fluorescein alone control. The slides were incubated for one hour at 27°C, washed 3 times and mounted with DAPI-containing medium (Vector Labs. Burlingame, CA, USA). The tissue sections were imaged with a Nikon Eclipse TE2000 inverted epifluorescence microscope by using Nikon objectives of 10· and 20· linear magnification with infinity correction. An X-Cite (Exfo, Vanier, Quebec, Canada) 120W metal halide light source and a liquid light guide were used to illuminate the tissue samples.