Cellular basis of morphogenesis

Abstract

ABSTRACT The relationship between cell density distributions and differentiation is of interest to workers in many different areas of developmental biology. Traditionally, such studies have required tedious counting of individual cells through a microscope eyepiece grid or on photographs. We have developed a rapid, reliable, and inexpensive microcomputer based system for counting cells in histological sections. The system employs an Apple He computer, Digisector video board (Micro Works, Del Mar, CA), Super Scan program (Magna Soft, La Canada, CA), Gibson Light Pen System (Gibson Laboratories, Laguna Hills, CA), and Telestar video camera (Bell and Howell). We have applied this to identify specific patterns of cell density in feathers. Our system is significantly different from other image analysis systems available because its low price (about $2500) makes it accessible to average laboratories, as opposed to the expensive image analysis systems which are available commercially or in a few special research laboratories. Normal feather germs, serial sectioned at 6 μ, and stained using the cold hydrolysis Feulgen technique were photographed at 400× using Kodak Tech Pan film and printed on Kodabromide paper (no. 5). One inch squares of the 4×6 inch print were exposed to the video camera. The correlation coefficient for the number of black pixels counted by the computer and the number of cells counted by hand from the photograph was >·98. Dramatic local increases in mesenchymal cell density in the area of the germ which protrudes distally were observed in the saggital sections of all the specimens examined. (Supported by NIH Training Grant 5T32AM07376.)