Problems in osteogenic differentiation of rat bone marrow stromal cells

The effect of rhBMP-2 in human bone marrow-derived stem cells as osteogenic inducers

Successive Suture Device for Gastrointestinal Endoscopes / 대한소화기내시경학회지

BACKGROUND/AIMS: Recently, treatment using an endoscopic device is actively being developed. Techniques for incision and bleeding control have been developed, but endoscopic suturing remains to be perfected. Using an endoscopic suturing technique, a variety of diseases could be managed noninvasively. We have attempted to use a new endoscopic suturing device which enables a continuous suture using a flexible upper endoscope. METHODS: A suturing device was designed where a semicircular needle could sew through tissue by rotation making a continuous suture possible. RESULTS: We successfully sutured the stomach tissue of a dog using an optimized suturing device model. CONCLUSIONS: The initial model was found to have some problems. However, we hope to develop a continuous suturing device for flexible upper endoscope procedures in Korea.

Mechanical Characterization of Self-Expandable Esophageal Metal Stents / 대한소화기내시경학회지

Backgound/Aims: One of the most important mechanical properties to consider in selecting clinically optimal stents would be expansile pressure. However, there were scanty data about the expansile pressure of stents. Furthermore, the data were improper for the clinical selection of stents. In this study, the authors tried to develop a precise and reproducible expansile pressure measurement method and to measure the expansile pressure of a variety of stent types. METHODS: We developed a new method of expansile force measurement using a cylindrical measurement device under a quasi-static equilibrium state and measured the expansile forces of six different stents made by various manufacturers; covered and uncovered Y2P SR , covered Y3E SR (Stentech, Korea), covered and uncovered Ultraflex and uncovered Wallstent (Boston Scientific, USA) RESULTS: Three important points critical in explaining and predicting the expansion characteristics of stents were found. Firstly, the radial expansion force varies greatly among the types of stents. Secondly, stents could be categorized to "soft stent" and "stiff stent" based upon the slope of expansion force change. Lastly, the initial force needed to compress the fully expanded stents is far greater in stents covered with membrane compared with the stents without membrane. CONCLUSIONS: The newly developed method of measurement helped the authors to get more realistic data of expansion force and pressure, which are thought to be helpful in clinical selection of stent type.

Current Tendency of Medical Technology change

No abstract available.

New Chronic Osteomyelitis Model in White Rabbit: A Preliminary Report / 대한정형외과연구학회지

The purpose of this study was to develope a rabbit model for the chronic osteomyelitis, which is reproducible, controllable in quantity of bacteria and suitable for toxicologic research and therapeutic intervention studies. Osteomyelitis was induced in white rabbits by injecting varying numbers of S. aureus(ATCC 19636, 49230) and Alginate-CaCl2 into the proximal metaphysis of tibia. Three rabbits were used in each number of S. aureus respectively. The tibia were harvested at 8 weeks later and evaluation was done by clinical, radiological and histological findings. Clinical sings of infection consisted of soft tissue swelling and limping in rabbits, Radiologic findings were periosteal reaction, osteolysis, new bone formation in proximal tibias. Histology showed chronic active inflammation, debris of alginate, clusters of bacterial and granulation tissue. In ATCC 19636(more than 6X105) inoculated rabbits, osteomyelitis was established consistently in all three rabbits. Using Alginate-CaCl2 and ATCC 19636 Staphylococcus aureus, we made a new chronic osteomyelitis model, reproducible and controllable in quantity of bacteria.