Resonance energy transfer is a spectroscopic method that allows the proximity of two labeled molecules to be probed on the angstrom-nanometer scale. The reduction in background allows lifetime measurements of resonance energy transfer to be made in tissue sections. Results in two different tissue types, skeletal muscle and cerebral cortex, are compared. Both calmodulin and dystrophin are found to be associated with actin, and no evidence is found for interactions between dystrophin and calmodulin. Meek, B., Routh, R., Marino, A., Landry, P., Sadasivan, K., McClain, O., and Rebtoy, L. Department Anatomy and Cell Biology, Oklahoma State University College of Osteopathic Medicine, Tulsa, and Department of Orthopaedic Surgery, LSU Medical Center, Shreveport.
Apoptosis is distinguishable by highly characteristic morphological changes.
Apoptotic bodies were observed within osteoblasts, and some of these larger apoptotic bodies contained nuclear and cytoplasmic elements. These structures were surrounded by clear areas which represented the halos of light microscopic view. Pale cells were viewed near blood vessels, which may represent a precursor to either typical macrophages or osteoblasts. In addition, at least one cell type may enter the repair area to function in phagocytic or osteoprogenitor activity. In conclusion, apoptosis appeared to be a normal part of fracture healing.