Surface-Modifying Effect of Zwitterionic Polyurethane Oligomers Complexed with Metal Ions on Blood Compatibility

BACKGROUND@#To prevent unsolved problems of medical devices, we hypothesized that combinatorial effects of zwitterionic functional group and anti-bacterial metal ions can reduce effectively the thrombosis and bacterial infection of polymeric biomaterials. In this research, we designed a novel series of zwitterionic polyurethane (zPU) additives to impart anti-thrombotic properties to a polyvinyl chloride (PVC) matrix. @*METHODS@#We have synthesized zPUs by combination of various components and zPUs complexed with metal ions. Zwitterion group was prepared by reaction with 1,3-propane sultone and Nmethyldiethanolamine and metal ions were incorporated into sulfobetaine chains via molecular complexation. These zPU additives were characterized using FT-IR, 1H-NMR, elemental analysis, and thermal analysis. The PVC film blended with zPU additives were prepared by utilizing a solvent casting and hot melting process. @*RESULTS@#Water contact angle demonstrated that the introduction of zwitterion group has improved hydrophilicity of polyurethanes dramatically. Protein adsorption test resulted in improved anti-fouling effects dependent on additive concentration and decreases in their effects by metal complexation. Platelet adhesion test revealed anti-fouling effects by additive blending but not significant as compared to protein resistance results. @*CONCLUSION@#With further studies, the synthesized zPUs and zPUs complexed with metal ions are expected to be used as good biomaterials in biomedical fields. Based on our results, we can carefully estimate that the enhanced anti-fouling effect contributed to reduced platelet adhesion.

Hybrid Natural Orifice Transluminal Endoscopic Surgery with Sentinel Lymph Node Navigation for Deep Early Gastric Cancer in the Fundic Region

For patients refusing surgical treatment for deep early gastric cancer, hybrid natural orifice transluminal endoscopic surgery with sentinel lymph node navigation is a potential treatment option, particularly when the anatomic location of the cancer has low probability of lymph node metastasis. We report a case of deep early gastric cancer of the fundus beyond the endoscopic submucosal dissection indication that was treated by hybrid natural orifice transluminal endoscopic surgery with sentinel lymph node navigation. In a conventional approach, a total gastrectomy would have been needed; however, the patient refused surgical intervention. In this case, since the patient showed no positivity of the sentinel lymph node on intraoperative navigation, laparoscopic basin lymph node dissection was not performed. Hybrid natural orifice transluminal endoscopic surgery might be considered for specific regions such as the safety zone where lymph node metastases are less likely to occur.

Repair of Osteochondral Defect Using Chitosan-collagen Sponge intheRabbit's Knee / 대한정형외과학회잡지

PURPOSE: To determine the suitability of using a chatoyant-collagen sponge as a scaffold for transplanting a chondrocyte into a full-thickness articular cartilage defect. MATERIALS AND METHODS: The in vitro characterization of a chatoyant-collagen sponge infiltrated with the chondrocyte was combined with an in vivo assessment of the early articular cartilage repair in a rabbit's knee by H&E and MTT staining. These porous chatoyant-collagen sponges were implanted into the osteochondral defects made in the left patellofemoral grooves of 12 rabbits. The osteochondral defects were untreated in the right side and used as controls. The experimental animals were sacrificed 1, 3, 6 and 12 weeks after implantation and the repaired tissue was evaluated by a gross and histological evaluation using the Wakitani score. RESULTS: More primary cells cultured from the articular cartilage of the rabbit's knee were found to attach to and survive within a porous chatoyant-collagen sponge than with a chatoyant sponge. In gross and histological examination, the experimental group showed indications of repair, which appeared similar in color and texture to the surrounding articular cartilage. The Wakitani scoring in the experimental group at 6 (Ave. 10.7) and 12 (Ave. 7.3) weeks were superior to those in the control group at 6 (Ave. 8.7) and 12 (Ave. 3.7) weeks (6 wk: p=0.03, 12 wk: p=0.02). CONCLUSION: Scaffolds composed of porous a chatoyant-collagen sponge enhance the growth of cartilaginous repair and make a milieu for the survival of chondrogenic cells both in vitro and in vivo.

Laparoscopy Assisted Distal Subtotal Gastrectomy with Lymphadenectomy - 202 Consecutive Cases

PURPOSE: The number of laparoscopy-assisted distal gastrectomy procedures for the treatment of early gastric cancer patient to improve the quality of life has been gradually increasing. This study evaluated the technical feasibility, safety, and surgical results of LADG with lymphadenectomy by reviewing the initial experience. METHODS: From May 2003 to December 2005, 202 LADG with lymphadenectomy were performed on patients with a preoperative diagnosis of EGC. The clinicopathological features and surgical outcomes were analyzed. RESULTS: There were 128 males and 74 females with a mean age of 58 years (range 24~78). The mean operation time was 212 minutes (range 105~450) and the operation time has decreased gradually with increasing number of cases. There were 16 operative morbidities (7.9%) including three operative mortalities. The restoration of the bowel sound was noted at 3.1 postoperative days, soft diet was started at 4.4 postoperative days and the duration of the hospital stay was 7.7 days. There were 105 mucosal, 64 submucosal, 22 proper muscle, 4 subserosal and 7 serosal lesions. A total 163 patients were treated with D2, 37 with D1+beta and 2 with D1+alpha LN dissection. The mean number of lymph nodes retrieved was 35 (range=10~81). Lymph node metastasis was noted in 30 patients. CONCLUSION: This study shows that laparoscopic procedure can be applied safely and effectively for the patients with EGC. However, a prospective study comparing laparoscopy-assisted versus open gastrectomy for the short- and long-term surgical outcomes is needed.

The Effect of Chitosan-TGF-beta1 Conjugate on Full Thickness Articular Cartilage Defect in the Rabbit Knee Model (Preliminary Report) / 대한정형외과연구학회지

PURPOSE: To evaluate the effect of the chitosan-TGF-beta1 conjugate on articular cartilage defects of rabbits' knees MATERIALS AND METHODS: Full thickness cartilage defect(6mm, round shape) was made at both knees of 20 rabbits and, after the lapse of 3 days, chitosan-TGF-beta1(15ng/ml, 1ml) was injected into one side(experimental group) of knees and PBS(1ml) was injected into the other side(control group). 5 rabbits were sacrificed 6 weeks after the injection and the rest of 15 rabbits 12 weeks later. Then, gross morphology and histological evaluation(Mendelson scoring) was conducted. RESULTS: No arthritic findings was observed and histological results in the experimental group at 6(Ave. 11.3+/-1.5) and 12(Ave. 4.5+/-1.9) weeks postoperatively were superior to those in the control group at 6(Ave. 14.6+/-1.7) and 12(Ave. 9.8+/-2.2) weeks. Especially at 12 weeks, the experimental group was superior to the control group statistically in results of 5 subgroups except for filling of defects. The difference of two groups at 12 weeks was more remarkable than those at 6 weeks. CONCLUSION: Regeneration of something very close to normal cartilage was observed in the experimental group. It shows that the biological activity of TGF-beta1 is sustained by the action of conjugate with chitosan, through prolonged half life of TGF-beta1.

Effect of Carboxy Methyl Chitosan on Experimental Osteoarthritis in a Rabbit Knee: Carboxy methyl chitosan vs. Hyaluronan / 대한정형외과학회잡지

PURPOSE: This study evaluates the effect on carboxy methyl chitosan on the articular cartilage of an osteoarthritic knee. MATERIALS AND METHODS: The biological effect of chitosan on the osteoarthritic articular cartilage was compared with hyaluronan, which is one of the treatment modalities for an osteoarthritic knee. Chitosan or hyaluronan were injected into the intraarticular space of the experimental osteoarthritic knee of a rabbit with a transected anterior cruciate ligament at weekly intervals for 5 weeks, and the articular cartilage and synovium were obtained. Nine weeks later, the specimens were analyzed by their gross findings, histological examinations, and histo-morphometric studies. RESULTS: The hyaluronan and chitosan group showed less severe osteoarthritic changes than the control group. Although the hyaluronan group showed less severe osteoarthiricic changes than the chitosan group, there was no statistical significance. CONCLUSION: Carboxy methyl chitosan, which has an excellent affinity to the body, appeared to have an positive effect on delaying the progress of cartilage degeneration.

Kidney Transplantation in a Patient with Idiopathic Thrombocytopenic Purpura / 대한이식학회지

Idiopathic thrombocytopenic purpura (ITP) is an autoimmune disorder characterized by the presence of IgG autoantibody against platelet, low platelet count, and bleeding disorders. Anecdotal experience of renal transplantation adopting the use of 2 weeks of steroids treatment, perioperative intravenous immunoglobulin, and simultaneous splenectomy in a patient with ITP was reported recently. However, advantage of these procedures is not yet confirmed. Recently, we performed a case of uneventful renal transplantation in a patient with ITP without immunoglobulin treatment and no splenectomy. Although platelet counts have been under normal limit after transplantation, the anti-platelet antibody converted to negative postoperatively and the graft function has been stable until now. Our case report raised the question about the use of perioperative immunoglobulin and splenectomy in these particular patient groups waiting for renal transplantation.

Culture of Rabbit Chondrocytes Using Chitosan Bead / 대한정형외과연구학회지

PURPOSE: To confirm the adhesion and matrix formation of chondrocytes which were cultured on chitosan beads and to elucidate the difference between the porous chitosan beads and non-porous chitsan beads as scaffold for chondrocytes. MATERIALS AND METHODS: Chondrocytes isolated from rabbit articular cartilage were cultured in vitro on porous and non-porous chitosan bead for 2 weeks. Histochemical (H&E stain, Toluidin blue stain) and scanning electromicroscopic approaches were used to compare the differences between two groups. RESULTS: In both groups, adhesion and proliferation of chondrocytes were observed on scanning electron microscopy. which were more active in the porous chitosan bead group. On histochemical staining with toluidine blue, the porous chitosan bead group showed stronger metachromasia than that of the non-porous chitosan bead. CONCLUSION: It is concluded that both chitosan beads could work as an effective scaffold for culturing chondrocytes, and that porous chitosan bead may be a better scaffold than non-porous chitosan bead because of cavities in former bead.