Improvements in dehydration and cement line staining for methacrylate embedded human bone biopsies

Undemineralized methacrylate embedded bone biopsies and other bone specimens can be processed much more rapidly by application of acidified 2,2-dimethoxypropane (DMP) dehydration, which requires two hours, than by traditional graded ethanol dehydration, which requires at least four days. This shortened processing time is valuable when biopsy results are urgently needed to detect osteomalacia or to determine bone features prior to possible parathyroidectomy. We have processed over 200 bone specimens with DMP and have compared DMP dehydration to graded ethanol dehydration in 11 biopsies in which two plugs were available from the same patient. DMP dehydration does not compromise the following: tetracycline retention, Goldner's stain, acid phosphatase localization or histochemical identification of aluminum. Cement lines, which provide a record of past remodelling, are useful in clinical interpretation of bone biopsies. We have adapted two stains, toluidine blue and methylene blue/basic fuchsin, for improved cement line identification. Five-micrometer sections individually demineralized in acetate buffer prior to cement line staining show best results with toluidine blue at pH 5.5 and with methylene blue/basic fuchsin at pH 2.5-3.5.