Bioengineered three-dimensional physiological model of colonic longitudinal smooth muscle in vitro.

Background: The objective of this study was to develop a physiological model of longitudinal smooth muscle tissue from isolated longitudinal smooth muscle cells arranged in the longitudinal axis.

Methods: Longitudinal smooth muscle cells from rabbit sigmoid colon were isolated and expanded in culture. Cells were seeded at high densities onto laminin-coated Sylgard surfaces with defined wavy microtopographies.

Impact of static and dynamic A-form heterogeneity on the determination of RNA global structural dynamics using NMR residual dipolar couplings.

We examined how static and dynamic deviations from the idealized A-form helix propagate into errors in the principal order tensor parameters determined using residual dipolar couplings (rdcs). A 20-ns molecular dynamics (MD) simulation of the HIV-1 transactivation response element (TAR) RNA together with a survey of spin relaxation studies of RNA dynamics reveals that pico-to-nanosecond local motions in non-terminal Watson-Crick base-pairs will uniformly attenuate base and sugar one bond rdcs by approximately 7%. Gaussian distributions were generated for base and sugar torsion angles through statistical comparison of 40 RNA X-ray structures solved to <3.