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Aspects of aging in human collagen: An exploratory thermoelastic study

1966; Elsevier BV; Volume: 5; Issue: 4 Linguagem: Inglês

10.1016/0014-4800(66)90039-6

1096-0945

Carleton D. Nordschow,

Rheology and Fluid Dynamics Studies

Abstract We have presented the results of a thermoelastic survey study into the measurement of differences in cross-linking densities among variously aged collagens. These studies have employed determinations of the minor and major melting points and the extent of dimensional change inducible by the major transition in the acidic (about 1.5–4.5) pH interval. We have shown that the major transition ( T 8 ) measured in the unswollen isoelectric state or the moderately swollen alkaline limit (pH 12.5) increases with age in a curvilinear fashion under isotropic conditions. In addition, the inducible shortening by melting in the acidic pH interval decreases with age. These observations are commensurate with a progressive increase in cross-link density with age. We have discussed the partial reversibility in the value of the minor transition in the isoelectric pH interval and suggested that this second order or “glass type transition” also may have its origin in the helix → coil shape transition which involves very short “band” helical chain segments. We discussed the fact that the destruction of collagen so familiar as “fibrinoid necrosis” of many disorders very likely is the result of hydrogen ion or other small molecule induced polymer dilution which permits major phase transition or melting at body temperatures. Finally, we called attention to the possibility that dimensional variations in collagenous structures, such as occurs in Marfan's syndrome, may be related to an unusually high cross-link density.