Paraffin Sections of Special Tissues
GUIDELINE
Certain tissues have special cutting protocols, most common for biopsies including liver, kidney, lung, striated muscle, spleen, skin, thyroid and breast carcinoma. Rapidly processed slide sections of them compared favorably with similar routinely processed tissue counterparts in regard to morphologic detail, cytologic clarity and staining properties. The shortened processing schedule provides a quick, simple, convenient, permanent section of selected biopsy specimens.
METHODS
- Six cylindrical biopsies of human tissue (1.0 x 0.1 x 0.1 cm) taken with a Vim Silverman needle or tissue blocks (0.4 x 0.1 x 0.1 cm) from autopsies or surgical specimens were used for each trial.
- Fix specimen in phosphate buffered formalin, alcoholic formalin or histological fixative for 45 minutes. Among them, histological fixative contains isopropyl alcohol (16.8% W/V), trichloracetic acid (2.0% W/V), paraformaldehyde (4.1% W/V) and a mordant (2.0 W/V).
- Dehydrate two times in acidified 2, 2-dimethoxypropane (DMP) (100 ml DMP + 1 drop HCl) for eight minutes each.
- Clear in xylene two times for 20 minutes each.
- All tissues from each organ were embedded in paraffin and sectioned at 5 microns on rotary microtomes with stainless steel knives.
NOTES
- Most sections had slightly increased eosinophilia regardless of fixation, especially after histological fixative.
- Most common for biopsies, there can be 2-5 levels per block, used to evaluate various planes of tissue. Typically, one level equals 8-10 sections of tissue, however each histotechnologist must use their own judgment/discretion when sectioning levels.
