title: Quantitative measurements of linear birefringence during heating of native collagen.
abstract: OBJECTIVE
  Linear birefringence is an anisotropic property of rat tail tendon, which is largely composed of collagen. Our goal is to show that the dynamic range and sensitivity of the linear birefringence loss of collagen during heating are sufficient for kinetic modeling of the reaction.
  
  
  METHODS
  The linear birefringence loss was quantified for tendon denatured via both a heated-isotonic-saline bath and a heated stage. All measurements were made with a polarizing transmission microscope equipped with a Berek compensator.
  
  
  RESULTS
  The data show that the loss of linear birefringence is a first-order kinetic reaction. The native rat tail tendon birefringence, delta n = 3.0 +/- 0.6 x 10(-3) (mean +/- std. err.), is lost after denaturation occurs (delta n = 0). Application of the Arrhenius equation to the linear birefringence data yields the activation energy (Ea = 89 +/- 1 kcal/mole), pre-exponential coefficient (A = e130 +/- 1 s-1), enthalpy (delta H = 88 +/- 1 kcal/mole) and entropy (delta S = 197 +/- 2 cal/degree K.mole).
  
  
  CONCLUSIONS
  This study shows that dynamic changes in linear birefringence can be used to monitor thermally induced changes in collagen.
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Maitland
authors.forename: J T
authors.initials: JT
authors.lastname: Walsh
mesh_terms: D000818:Animals; D016880:Anisotropy; D001718:Birefringence; D003094:Collagen / Q000648:ultrastructure*; D006358:Hot Temperature; D008859:Microscopy, Polarization; D051381:Rats; D017207:Rats, Sprague-Dawley; D013623:Tail; D013710:Tendons / Q000648:ultrastructure
chemical_list: D003094:Collagen