Effect of BaSO4 in Bone Cement on Rat Osteoblast / 대한정형외과연구학회지

PURPOSE: We hypothesize that the presence of barium sulfate debris plays an influential role to deteriorate the balance of bone remodelling around prosthesis via cytotoxic mechanism to osteoblast. MATERIALS AND METHODS: Osteoblasts were obtained from the neonatal rat calvarium, and SiO2, TiO2 , PMMA and BaSO4 particles were prepared for the evaluation of particle induced cytotoxicity to osteoblast. Osteoblasts were grown in DMEM and then were seeded into 6 well culture plates. 1.0wt% solution of each particle was added to culture medium to generate a final concentration of 0.1wt%, and 0.005wt% of various particles in each well, respectively. The measurement of intracellular calcium was conducted using various agonists of calcium. The cell viability assay for osteoblast was performed with MTT reduction assay and the mineralization of the matrix was checked by Von Kossa staining. ELISA kit was used to quantify the level of osteocalcin in osteoblast. RESULTS: BaSO4 significantly lowered the cell viability. All particles except TiO2 increased [Ca(2+)]i transiently, and the rank of differential cytosolic [Ca(2+)]i was in order as follows; SiO2, BaSO4, and PMMA. The mineralization was significantly prohibited in SiO2 and BaSO4(0.1wt%), however the PMMA showed no definite inhibitory effect on bone mineralization. PMMA(0.1wt%) and BaSO4(0.1wt%) showed significantly inhibitory effect on osteocalcin production. CONCOUSION: In higher concentration, BaSO4 has a cytotoxic effect on osteoblast and inhibitory effect of osteocalcin production as well as mineralization of osteoblast. Also, this study has shown that the concentration of intracellular calcium is strongly influenced by exposure to BaSO4 particles in vitro. The effect of BaSO4 on osteoblast observed in this study could have implications for the role of BaSO4 particles on osteoblast function at aseptic loosening of cemented total joint arthroplasty.

The Results of Renal Transplantation after Lymphocyte Cross-match Negative Conversion by Combination Therapy with Plasmapheresis, Intravenous Gamma Globulin and Potent Immunosuppresants in Patients with Positive LCM / 대한이식학회지

PURPOSE: It is well-known that kidney transplantation cannot be done if recipient has circulating antibodies showing positive lymphocyte cross-match (LCX) to organ donor. In the United States and European countries, the incidence of positive LCX to cadaveric donors in patients who are on the waiting list is up to 20~40%. Unfortunately, these patients also show high rate of positive LCX to live donors when they have donor candidates in their family members and have to be on dialysis until compatible donor comes up. Recently, Eugene J Schweitzer and his associates at the University of Maryland used the combination therapy with plasmapheresis, intravenous gamma globulin and potent immunosuppression to induce negative conversion of LCX in patients who were LCX positive to their living donors and reported the good results after the trial. We did the combination therapy in patients who had positive LCX to their living donors and reported the results. METHODS: Seven patients, four women and three men who showed positive LCX to their living donors, underwent the conversion trials between January 1 and July 31, 2002. The mean age of patients was 43.86 (35~60) and the duration of dialyses varies from 9 to 120 months. We used combination therapy with plasmapheresis, intravenous gamma globulin injection, tacrolimus, mycophenolate mofetil (MMF) and steroids. Plasmapheresis had been done on every other day up to 6 times to induce negative conversion of LCX. If patient continue to show positive LCX to donor after 6 times of plasmapheresis, we stopped the therapy. The numbers of plasmapheresis varies from two to six times. Kidney transplantations were preformed immediately after negative conversion of LCX as a semi-elective procedures. Five to ten day courses of ATG (or OKT3) were used as an induction immunosuppression after transplantation and tacrolimus, MMF, and steroids were used as a maintenance immunosuppression. RESULTS: We could achieve negative conversion of LCX in six out of seven patients, and kidney transplantations were performed in these 6 patients successfully. There was no hyperacute rejection during the operations, but three patients developed acute rejection episodes during their early postoperative periods. Steroid pulse therapies were used as a primary therapy to treat acute rejection and all three patients showed complete recovery of their graft function after the treatments. Baseline serum creatinine level varies from 1.0 mg/dl to 1.9 mg/dl with 3 to 6 months follow-up periods after transplantations. We could not induce negative conversion in one patient and he remained on hemodialysis. CONCLUSION: We did successful kidney transplantations in six patients who achieved negative conversion of LCX to their donors after the combination therapy with plasmapheresis and potent immunosuppression. All patients showed excellent graft function since their operations and did not have any significant complications except three reversible acute rejection episodes. According to the results, although it is preliminary, we recommend the use of the combination therapy in patient who has LCX positive living donor. Further long-term study with more numbers of patients is needed for the evaluation of the efficacy of this trial.