R G MacBride1. 1. Department of Biological Sciences, Delaware State University, Dover 19901, USA. rmacbrid@dsc.edu
Abstract
BACKGROUND: Embalmed cadavers in medical classes represent a potential source for collecting human tissues without the inherent problems of obtaining fresh or surgical specimens. Although the manner of fixation and vagaries of embalming techniques eliminate many such tissues for histological assessment, other techniques can be applied successfully to embalmed tissues. Pertinent to the present study, mast cells contain granules that are preserved under good fixation in formaldehyde, a main ingredient in embalming fluids. Visualization of these granules is possible, even though the ultrastructure of these cells is not preserved. METHODS: Two techniques for the visualization of connective tissue mast cells were compared using embalmed and fresh specimens: Alcian blue and avidin conjugated to fluorescein isothiocyanate (FITC-Avidin). Both will bind to mast cell granules, even in the presence of formaldehyde. RESULTS: Although mast cell numbers in the connective tissue did not differ between embalmed and fresh tissues, comparisons between the techniques involved showed the FITC-Avidin technique to be possibly more sensitive, perhaps because of the increased contrast from the fluorescent dye. CONCLUSIONS: Thus for some studies, human cadavers may provide a valuable source of tissue. However, use of embalmed tissue necessitates ensuring good embalming, checking for dehydration, and proper storage until embedment.
BACKGROUND: Embalmed cadavers in medical classes represent a potential source for collecting human tissues without the inherent problems of obtaining fresh or surgical specimens. Although the manner of fixation and vagaries of embalming techniques eliminate many such tissues for histological assessment, other techniques can be applied successfully to embalmed tissues. Pertinent to the present study, mast cells contain granules that are preserved under good fixation in formaldehyde, a main ingredient in embalming fluids. Visualization of these granules is possible, even though the ultrastructure of these cells is not preserved. METHODS: Two techniques for the visualization of connective tissue mast cells were compared using embalmed and fresh specimens: Alcian blue and avidin conjugated to fluorescein isothiocyanate (FITC-Avidin). Both will bind to mast cell granules, even in the presence of formaldehyde. RESULTS: Although mast cell numbers in the connective tissue did not differ between embalmed and fresh tissues, comparisons between the techniques involved showed the FITC-Avidin technique to be possibly more sensitive, perhaps because of the increased contrast from the fluorescent dye. CONCLUSIONS: Thus for some studies, human cadavers may provide a valuable source of tissue. However, use of embalmed tissue necessitates ensuring good embalming, checking for dehydration, and proper storage until embedment.