How to Yield High-Quality Paraffin Sections? Paraffin sectioning is the most frequently used method for histological section preparation. However, paraffin-embedded tissue.Why can’t wax block be trimmed smoothly? Why section breakage and coiling are easy to occur during the cutting? Why the sections can’t be flattened during spreading? This text will provide you with the detailed methods of cutting qualified paraffin sections. Correct fixation After tissue separation, it is required to fix it within 1 hour. The stationary liquid shall be 4 to 10 times the volume of the tissue and have an accurate concentration. Excessively thin and rich liquid will affect tissue form and fixation effect. In case of discovering any stationary liquid deterioration, such as white precipitation of formaldehyde liquid, it is required to conduct immediate replacement. The fixation temperature should be the ambient temperature or in a fully enclosed tissue processor of 35-37°C. Excessively high temperature will accelerate tissue autolysis and excessive contraction and destroy the antigen and DNA in the cells. The fixation time shall not exceed 40 hours and shall be adjusted according to the ambient temperature and specimens. Appropriate dehydration The key to dehydration is make the low-concentration alcohol dehydration time match the high-concentration alcohol dehydration time. Low-concentration alcohol can reduce tissue shrinkage and make it easier to cut. High-concentration alcohol can dehydrate tissues even more. Generally, the specimen dehydration time (35°C) is 1.5 hours for 75% alcohol, 2 hours for 85% alcohol, 1.5 to 2 hours for 95% alcohol (twice), and 1.5 to 2 hours for pure alcohol (twice). The dehydration time of small specimens is little different from that of large specimens. Normally, there’s no need to separate them (often, brittle small specimen is a result of thick paper package or sticking with each other, which leads to incomplete tissue dehydration. If the time i

urgent, it’s allowed to properly shorten the dehydration time. The duration of dehydration is closely related to the ambient temperature, the thickness and type of the tissue, the degree of tissue fixation, etc.). The thoroughness of dehydration is directly associated with tissue transparency. If the temperature is too high (beyond 50°C) or acetone is used during dehydration, it can easily lead to excessive tissue shrinkage and hardened and brittle tissues. There are three reasons for brittle tissue caused by tissue dehydration: False fragility: due to insufficient dehydration, the paraffin cannot...