An immunocytochemical analysis of torn rotator cuff tendon taken at the time of repair.

During rotator cuff repairs, it is recommended that the hypovascular tissue edge be resected. To investigate rotator cuff tendon histopathology, we performed immunohistochemistry on 8 surgical and 6 cadaveric specimens. Hoechst nuclear stain and standard hematoxylin-eosin were used for morphologic analysis. Antibody to human von Willebrand factor tagged with fluorescein isothiocyanate, conjugated, was used to visualize vascularity, and antibody to human procollagen type I tagged with Cy3 was used to visualize new procollagen synthesis. There were no significant differences in the vascularity of surgical specimens sectioned near the tear site (<2.5 mm from tear margin) and matched cadaveric controls. However, sections taken 2.5 to 5 mm away from the tear demonstrated more vessels than those taken from either control or surgical specimens within 2.5 mm of the tear (P <.001). There were no differences in nuclear distribution patterns or in procollagen production and distribution between surgical specimens from sites near the tear or away from the tear. On the basis of morphologic architecture, these data suggest that minimal debridement of tendon edges only is required to maximize healing of the rotator cuff tendon at the time of repair.

HSP22, a new member of the small heat shock protein superfamily, interacts with mimic of phosphorylated HSP27 ((3D)HSP27).

Most of the members of the superfamily of mammalian small heat shock or stress proteins are abundant in muscles where they play a role in muscle function and maintenance of muscle integrity. One member of this protein superfamily, human HSP27, is rapidly phosphorylated on three serine residues (Ser(15), Ser(78), and Ser(82)) during cellular response to a number of extracellular factors. To understand better the role of HSP27, we performed a yeast two-hybrid screen of a human heart cDNA library for HSP27-interacting proteins. By using the triple aspartate mutant, a mimic of phosphorylated HSP27, as "bait" construct, a protein with a molecular mass of 21.6 kDa was identified as an HSP27-binding protein. Sequence analysis revealed that this new protein shares an overall sequence identity of 33% with human HSP27. This protein also contains the alpha-crystallin domain in its C-terminal half, a hallmark of the superfamily of small stress proteins. Thus, the new protein itself is a member of this protein superfamily, and consequently we designated it HSP22. According to the two-hybrid data, HSP22 interacts preferentially with the triple aspartate form of HSP27 as compared with wild-type HSP27. HSP22 is expressed predominantly in muscles. In vitro, HSP22 is phosphorylated by protein kinase C (at residues Ser(14) and Thr(63)) and by p44 mitogen-activated protein kinase (at residues Ser(27) and Thr(87)) but not by MAPKAPK-2.

Morphological study of two human facial muscles: orbicularis oculi and corrugator supercilii.

Human facial muscles are unique in that they do not cross joints and they function either to open and close the apertures of the face or to tug the skin into intricate movements producing facial expressions. Compared to other skeletal muscles of the body, little is known about the microscopic architecture and organization of facial muscles. It was hypothesized that facial muscles with different roles would possess differences in their cellular organization and morphology that would reflect their unique function. The palpebral orbicularis oculi (oo) and the corrugator supercilii (cs) were studied because they are in close topographical proximity to one another and share the same nerve supply and embryonic origin. This study compared the two muscles which were procured as biopsies from cosmetic surgery procedures. Architectural and morphological features were elucidated using a combination of conventional histological stains, immunocytochemistry and histochemistry. Quantitative measures of fiber sizes, shapes, and fiber-type distributions were performed along with measures of capillary area per unit of contractile area (capillary index). Fiber-type profiles and motor end-plates were demonstrated by using antibodies to fast and slow myosins, as well as to neurofilament protein. The oo was shown to differ significantly from the cs on the basis of fiber shapes, sizes, and types. The oo muscle fibers were small, rounded, and 89% of them were of the fast-twitch (Type II) variety. The muscle fibers in the cs were larger, polygonal, and only 49% of them were of the fast-twitch variety. The capillary index of the cs was 2.4 times that of the oo.