Method for the Correlation of Chemical and Histologic Composition

Two micro-modifications are described for determination of hydroxyproline. These methods were used on ribbons of 5-/tm his-tologic sections. Adjacent sections were pro-jected and traced, and tracings were cut and weighed to determine the area of connective tissue. Quantitative chemical concentrations of collagen in histologic sections were de-termined. Histologic observations are sometimes in-terpreted quantitatively. However, histo-chemistry often depends on qualitative judgment, and histologic observations gen-erally are not expressed in strictly quantita-tive terms. The present study demonstrates the correlation of microscopic observations and biochemical determinations. The col-lagen content of healing human gingival tissues was studied by a serial sectioning technic that has been used on gastric mu-cosa, barley seeds, and chicken embryos.1-4 Materials and Methods SERIAL SECTIONS.-A block of paraffin-embedded gingiva was rotated so that the outer epithelial surface was facing the microtome blade. Sections were cut at 5 micrometers ([tm). As the cutting pro-gressed, larger amounts of connective tissue appeared in the sections. Three successive sections were placed on a slide and left unstained. Five sections on another slide were stained for histologic examination. This course was repeated for the remainder specimen. To determine the volumes of connective tissue in the sections used for analysis, the images were projected on a ground glas