Hydrothermal isometric tension curves from different connective tissues. Role of collagen genetic types and noncollagenous components.

Variations in hydrothermal isometric tension (HIT) were recorded in tendons, ligaments, skin, blood vessels, nerves, palatal mucosa, lungs, muscles, cartilages, demineralized bones and dentine from donors of different ages and species. The curves obtained during a linear rise in temperature from 37 degrees C to 100 degrees C at a rate of 1.15 degrees C/min were classified into three major families, A, B and C, depending on whether these curves displayed an early maximum, two shoulders or a late maximum. The ratio of heat-labile to heat-stable cross-links in the tissue's collagen network was shown to determine the type of curve obtained, but the genetic types of collagen in the tissue and the amount and quality of its noncollagenous components were not important in this respect. These results are discussed in the light of the accepted view that HIT variations are due to the rubber-elastic properties of gelatin.