Domains of differential cell proliferation suggest hinged folding in avian gut endoderm.

A profile of proliferative growth assessed with tritium autoradiograms from White Leghorn embryo stages Hamburger-Hamilton 6-21 labeled in ovo presents evidence of hinged folding driven by localized differential cell proliferation in endoderm. There is a significant, bilateral pattern, and differences are most pronounced in axial levels that are folding and rotating. Highest proliferation is in cells producing folds; lowest proliferation is in median cells.

Reproducible measurements to quantify cutaneous involvement in scleroderma.

Background And Design: Because the current assessment of scleroderma through clinical skin scoring is subjective and imprecise, we devised fully quantitative measures of cutaneous involvement. First, we developed image analysis software for calculating the density of dermal collagen from 58 scleroderma and 327 control biopsy specimens. Second, using a durometer gauge, we obtained measurements of skin hardness over 12 body regions for 13 patients with scleroderma and 100 controls.