Takuya Shimizu

Basic fibroblast growth factor has a beneficial effect on the viability of random skin flaps in rats

We investigated the effect of exogenous basic fibroblast growth factor (bFGF) on the viability of random skin flaps in rats. Thirty-six rats were divided into three groups of 12 animals: a saline control group and two bFGF-treated groups. Caudally based random skin flaps were raised on the backs of the rats. In the control group, saline was instilled under the flap after skin closure. Twelve other rats were treated with bFGF (20 μg) just after skin closure. The remaining 12 rats were treated twice with bFGF (20 μg), both just after the operation and 48 hours later. There was a significant improvement in viability in the bFGF-treated groups on postoperative day 7 compared with the control group. Total adenine nucleotide levels in the flaps on postoperative day 10 were significantly higher in the group receiving two doses of bFGF than in the other groups. Thus, bFGF can improve the viability of endangered skin flaps.

Unicompartmental knee arthroplasty for medial gonarthrosis: 5 to 9 years follow-up evaluation of 77 knees

Abstract A total of 77 knees in 60 consecutive patients were operated on for medial gonarthrosis using a cemented porous coated anatomical (PCA) unicompartmental knee arthroplasty. Their average age was 71.3 years; 11 were men and 49 women. Clinically, the results in 67 knees were rated as being good to excellent, with mean preoperative and postoperative flexion of 123 and 122 deg, respectively. No deep infections or deep venous thrombosis occurred, but there was one dislocation of the femoral component. Overall clinical and radiographic results were satisfactory in 88% at 7.0 years’ follow-up. Kaplan-Meier survivorship analysis indicated that the failure rate of unicompartmental knee arthroplasty was 12% at average follow-up. In patients aged 70 years or more, unicompartmental knee arthroplasty for medial gonarthrosis should be considered an excellent alternative to high tibial osteotomy.

The expression of matrix metalloproteinases and inhibitors in acute rupture of the anterior cruciate ligament

Abstract Rapid degeneration of the anterior cruciate ligament (ACL) may occur after ligament rupture, making primary repair of the anterior cruciate ligament difficult. Nine completely ruptured anterior cruciate ligaments were collected by arthroscopic surgery performed within 6 months of injury. The authors studied the localization of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases in ruptured anterior cruciate ligament using immunohistochemistry, and measured messenger ribonucleic acid expression using the reverse transcriptase polymerase chain reaction. Cells in residual ligament tissue seemed to contain matrix metalloproteinases 1 and 3 and tissue inhibitors of matrix metalloproteinases 1 and 2. Promatrix metalloproteinase-9 positive cells were observed in the perivascular area. Promatrix metalloproteinase-2 positive cells frequently were seen between irregular collagen bundles in stumps of ruptured ligaments. Tissue inhibitors of matrix metalloproteinase-2 positive cells commonly were observed in ruptured ligaments. Matrix metalloproteinase-1 and matrix metalloproteinase-3 messenger ribonucleic acid were highly expressed compared with matrix metalloproteinase-2 messenger ribonucleic acid. Tissue inhibitor of matrix metalloproteinase-2 messenger ribonucleic acid was highly expressed compared with tissue inhibitor of matrix metalloproteinase 1. The authors could not identify whether these intrinsic reactions mediated by anterior cruciate ligament cells were the causes of rapid degradation or the results of the degradation process. Various amounts of matrix metalloproteinase and inhibitor production of intrinsic ligament cells were observed in the ruptured anterior cruciate ligament. The biological reaction reported in this study may suggest that pronounced metabolism is undertaken in ruptured ACL cells, and provide useful insight concerning the possiblitiy of achieving the primary repair of ruptured ACL.

Effect of parathyroid hormone (PTH) on replantation of amputated legs in a rat model.

Bone atrophy following replantation of an amputated extremity is related to the decrease of blood flow and to disuse. The effect of parathyroid hormone (PTH) on bone atrophy and bone formation was the subject of the reported study. Lewis rats were divided into amputated and replanted, and non-amputated groups, with the groups further divided into subgroups, with and without the administration of PTH. The agent (0.8 U/0.2 ml) was administered subcutaneously three times a week for 5 consecutive weeks, while controls were given 0.1 percent BSA buffer solution (0.2 ml) subcutaneously three times a week for 5 consecutive weeks. Subsequently, the animals were anesthetized, blood samples were taken, and tibias were extracted before sacrifice. Laboratory evaluations included bone assays and the measurement of bone mass and volume. In the group given PTH after amputation and replantation, there was increased bone formation, together with significant increases in bone Ca, bone P, ash content volume, and volume and serum alkaline phosphatase (Al-p), in comparison with the other groups. The administration of PTH after amputation and replantation was comparatively effective in mitigating the amount of bone damage.