Accidental modification of Attwood's stain on decalcified preparations, yielding improved differentiation between woven and lamellar bone.

In an earlier report, a modification of the Attwood's stain was used to study sections of decalcified bone and the procedure aided in the distinction between lamellar and woven bone. Lamellar bone showed preferential affinity for phloxine (red) yet resisted differentiation with tartrazine (yellow), while woven bone stained well with tartrazine. In addition, osteoid seams were identified by their affinity for tartrazine. Differential staining was abolished by pretreatment with periodic acid. Recently, accidental use of potassium permanganate in an acidified medium of pH 1.94, instead of pH 6.44, yielded unexpected results with a much sharper, consistent distinction between woven and lamellar bone. This probably reflects changes in the noncollagenous, interfibrillary matrix proteins of bone, but the exact reason(s) is not known. In our view, this serendipitous modification represents an advance over the previous method, and has allowed us to study the structure of bone in some of the systemic disorders, e.g., osteogenesis imperfecta, with greater ease than before. This method does, however, suffer the disadvantage of interfering with the intensity of the staining of any cartilaginous matrix, and the original application is still of value.