Scanning Electron Microscopy


Hypertrophic scars contain highly pleomorphic cells, including many from the erythrocytic series which have been extravasated. The conventional visual mode of SEM cannot distinguish the cell types with certainty except in the case of typical biconcave disc-shaped erythrocytes. Microprobe elemental analysis might be used to differentiate one type from another on the basis of iron and possibly phosphorus (for nucleated cells). Using coated specimens (gold or gold-palladium) precludes simultaneous visual mode SEM with EDX because of energy line interference with phosphorus and other elements. However, wave-length dispersive analysis offers minimal or no interference, and a coated specimen offers the use of a simultaneous visual mode. We wished to determine if useful elemental data could be obtained from specimens previously prepared only with the purpose of SEM mode studies. Therefore they were not prepared according to contemporary optimal methods. Analysis demonstrates that one group of cells contains 45% or more (dry weight concentration, absolute) iron as opposed to markedly low values in other cell types. Values for phosphorus do not appear essentially different among the cell types except in the case of standard erythrocytes where it is very low. Calcium and sulfur content was also examined. Sulfur might be useful in identifying another cell type in the hypertrophic scar. Using cells and matrix in developing deer antler for control values, the ratio of calcium to phosphorus found in the mineralizing matrix was essentially the predicted value. It is concluded, therefore, that even with a substantially heavy coating of gold, values for the elements tested (Fe, P, Ca, S) are not seriously compromised.

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