Arthroscopic rotator cuff repair:Indications and technique

Arthroscopic repair of rotator cuff tears is now possible. By using the biomechanical principles of margin convergenceand the balance of force couples, even large cuff defects can be repaired. Suture anchors are particularly suitable for arthroscopic repairs, and a corkscrew anchor design lends itself to a trans-tendon approach     

Decreased Efficacy of Topical Anesthetic Creams in Presence of Benzoyl Peroxide

Background. Topical anesthetics are widely used to diminish the sensation of pain from various medical cutaneous procedures. Any topical agent that reduces the desired effect has clinical ramifications.
Materials and Methods. Topical 6% benzocaine cream was applied to both inner forearms of five persons and covered with a bandage. One of the arms was additionally treated simultaneously with 5% benzoyl peroxide. The areas were tested with a pinprick examination every 10 minutes for the ensuing hour.
Results. There was an estimated 75% increased perception of pain on the forearm to which benzoyl peroxide was applied in consort with the topical anesthetic at all examination times.
Conclusions. Benzoyl peroxide chemically reacts with topical anesthetics such as tetracaine, procaine, pramoxine, prilocaine, and lidocaine, causing a significant reduction in their numbing effect. Clinically, make sure that the skin area to be topically anesthetized is devoid of any previous treatment with benzoyl peroxide or insist that the skin is thoroughly washed prior to application of the anesthetic.
CRAIG G. BURKHART, MPH, MD, AND CRAIG N. BURKHART, MSBS, MD, HAVE INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS.     

A novel 37-Kd adhesive membrane protein from cloned murine bone marrow stromal cells and cloned murine hematopoietic progenitor cells

The adhesion of hematopoietic progenitor cells to bone marrow stromal cells is critical to hematopoiesis and involves multiple effector molecules. Stromal cell molecules that participate in this interaction were sought by analyzing the detergent-soluble membrane proteins of GBI/6 stromal cells that could be adsorbed by intact FDCP-1 progenitor cells. A single-chain protein from GBI/6 cells having an apparent molecular weight of 37 Kd was selectively adsorbed by FDCP-1 cells. This protein, designated p37, could be surface-radiolabeled and thus appeared to be exposed on the cell membrane. An apparently identical 37- Kd protein was expressed by three stromal cell lines, by Swiss 3T3 fibroblastic cells, and by FDCP-1 and FDCP-2 progenitor cells. p37 was selectively adsorbed from membrane lysates by a variety of murine hematopoietic cells, including erythrocytes, but not by human erythrocytes. Binding of p37 to cells was calcium-dependent, and was not affected by inhibitors of the hematopoietic homing receptor or the cell-binding or heparin-binding functions of fibronectin. It is proposed that p37 may be a novel adhesive molecule expressed on the surface of a variety of hematopoietic cells that could participate in both homotypic and heterotypic interactions of stromal and progenitor cells.