Rigorous analysis of light diffraction ellipsometry by striated muscle fibers.

A rigorous analysis of both the transverse electric and the transverse magnetic modes of light diffracted from a muscle fiber is performed. From the expressions of electromagnetic field components, ellipsometry parameters, differential field ratio, r, and birefringence, delta n, have been obtained. A theoretical formulation that introduces myofibril skew planes and a randomization factor about the average skew plane yields a relationship that shows good fit to experimental data of Chen et al. (Biophys. J. 56:595, 1989) and Burton et al. (J. Muscle Res. Cell Motil. 11:258, 1990). Using indices of refraction within each of the regions of the sarcomeric unit that are consistent with our knowledge of the molecular structure of the sarcomere in the analysis, it is shown that the transition from the rigor state to the resting state leads to as much as a approximately 13% decrease in the r-value and an equally significant change in delta n.