John Cambridge

Ostene, a new water-soluble bone hemostasis agent.

Traditional formulations of bone wax are composed largely of beeswax and are well known to interfere with bone healing and cause inflammatory reactions. Ostene, a newly available bone hemostasis agent made of water-soluble alkylene oxide copolymers, was evaluated. The soft tissue response to Ostene was compared with bone wax and a polyethylene control after implantation into the paravertebral muscles of three rabbits. After 2 weeks, Ostene elicited no fibrous response, the polyethylene elicited a thin (less than 0.5 mm) fibrous response, and the bone wax was encased in a fibrous capsule 0.6 to 1.0 mm thick infiltrated with inflammatory cells. The effects of Ostene were compared with bone wax in a femur defect model in eight rabbits. Ostene showed no evidence of an adverse response in the cortical defect site, medullary cavity, or the surrounding tissue at 4 and 8 weeks. In contrast, bone wax at both time intervals elicited a foreign body response consisting of fibrous tissue infiltrated by macrophages, giant cells, and lymphocytes at the sites of the bone defects. Bone wax also displaced the bone marrow and interfered with bone ingrowth into the defects. Ostene provides the clinician a water-soluble bone hemostasis material that does not demonstrate the adverse tissue response or the interference with bone healing seen with the use of bone wax.

The Effects of a Soluble Polymer and Bone Wax on Sternal Healing in an Animal Model

PURPOSE This study compares the effects of a soluble polymer hemostatic material and bone wax on sternal bone healing. DESCRIPTION Median sternotomies were performed on 20 New Zealand White rabbits, and sufficient polymer (Ostene; Ceremed Inc, Los Angeles CA) or bone wax (Bone Wax; Ethicon Inc, Somerville, NJ) was applied to achieve bone hemostasis. After 6 weeks, sternal healing was assessed using roentgenograms, histology, and mechanical strength testing. EVALUATION Roentgenograms revealed normal bone healing in the polymer-treated group and nonunion in the bone wax group. Histology showed normal bone healing in the polymer group, with fibrotic scar tissue and the absence of new bone formation in the bone wax group. Mechanical strength testing showed that polymer-treated sternal segments were twice as strong as those treated with bone wax. They had a significantly higher flexural strength (2.53 +/- 0.43 vs. 1.29 +/- 0.37 megapascal [MPa]; p < 0.001) and Youngs modulus (0.315 +/- 0.056 vs 0.146 +/- 0.031 MPa; p < 0.001). CONCLUSIONS The application of the polymer hemostatic material to the sternum resulted in significantly stronger union compared with the use of bone wax.

A Novel High-Throughput Screening Assay for Sickle Cell Disease Drug Discovery

Although the pathophysiology and molecular basis of sickle cell disease (SCD) were described more than half a century ago, an effective and safe therapy is not yet available. This may be explained by the lack of a suitable high-throughput technique that allows rapid screening of thousands of compounds for their antisickling effect. The authors have thus developed a novel high-throughput screening (HTS) assay based on detecting the ability of red blood cells (RBC) to traverse a column of tightly packed Sephacryl chromatography beads. When deoxygenated, sickle RBC are rigid and remain on the top of the column. However, when deoxygenated and treated with an effective antisickling agent, erythrocytes move through the Sephacryl media and produce a red dot on the bottom of the assay tubes. This approach has been adapted to wells in a 384-well microplate. Results can be obtained by optical scanning: The size of the red dot is proportional to the antisickling effect of the test molecule. The new assay is simple, inexpensive, reproducible, requires no special reagents, and should be readily adaptable to robotic HTS systems. It has the potential to identify novel drug candidates, allowing the development of new therapeutic options for individuals affected with SCD. (Journal of Biomolecular Screening. 2009:330-336)