Effect of low intensity pulsed ultrasound (LIPUS) on bone healing around a titanium implant in the tibia of osteoporosis-induced rats

INTRODUCTION: Osteoporosis is a major health problem in the elderly that involves changes in the properties of bone as well as impaired bone healing around a titanium implant in both humans and animals. This study examined effect of low intensity pulsed ultrasound (LIPUS) on the bone healing process around a titanium implant in osteoporosis-induced rats. MATERIALS AND METHODS: Sixteen rats were divided into two groups. A control group with osteoporosis induced by removing both ovaries and an experimental group of rats that were applied with LIPUS after osteoporosis had been induced. A screw type titanium implant (diameter, 2.0 mm: length, 3.5 mm, Cowell-Medi, KOREA) was placed into the tibias of 16 rats. The control and experimental group contained 8 rats each. The rats were sacrificed at 1, 2, 4, and 8 weeks after implantation to examine the histopathology and immunochemistry. RESULTS: The histopathology examination revealed earlier new bone formation in the experimental group than the control group. In particular, at 1 week after implantation, more new bone matrix and collagen were observed around the implant of the experimental group compared to the control group. Immunochemistry analysis showed that the level of OPG expression of the experimental group was higher in the early stages than in the control group. After 8 weeks, the levels of OPG expression were similar in both groups. The expression level of receptor activator of nuclear factor kB ligand (RANKL) was stronger in the experimental group than the control group. After 4 weeks, the level of RANKL expression was similar in both groups. CONCLUSION: These results suggest that the application of LIPUS to implantation can promote bone healing around titanium in osteoporosis animals.

Apoptotic Effect of Combination Treatment with a Proteasome Inhibitor, Lactacystin, and a Histone Deacetylase Inhibitor, Trichostatin A, on MCF-7 Cells / 대한해부학회지

Although much information has been accumulated about the synergistic interaction of proteasome inhibitors and HDAC inhibitors to induce apoptosis in a certain type of cells, much less is known currently about the underlying mechanism. This study was undertaken to explore the combination effect of a histone deacetylase inhibitor, TSA, and a proteasome inhibitor, lactacystin, on the induction of apoptosis. Pretreatment of TSA and subsequent treatment of lactacystin showed the strong antitumor activity and nuclear condensation. Western blot assay showed that combination treatment of TSA and lactacystin increased Bax/Bcl-2 ratio and decreased level of XIAP. Activation of caspase-7 and cleavage of PARP were demonstrated after the combination treatment. In combination treatment group, cell cycle arrest was induced at G2/M phase and abolished increase in proteasome activity. This study is elucidating the mechanims whereby targeting apoptotic machineries may help in directing therapeutic strategies.

Mandibular distraction osteogenesis with compression force: Bone density, histological findings and TMJ response

Evaluation of Coagulation Function in Hip Replacement Arthroplasty Using Thromboelastography / 대한마취과학회지

BACKGROUND: Hip replacement arthroplasty is highly traumatic and may be associated with serious perioperative cardiorespiratory and vascular complications. Bone traumatization induces activation of the hemostatic system. A method of assessment of hemostatic function with whole blood is thromboelastography (TEG), which is a sensitive indicator of platelet interreaction with protein coagulation cascade. The authors investigated the effect of bone cement on blood coagulation during hip arthroplasty by TEG. METHODS: Sixty patients scheduled for hip replacement arthroplasty were randomly allocated to either a noncemented group (n = 35) or cemented group (n = 25). All the patients were operated on under general anesthesia. Collected 0.36 ml blood samples were measured by TEG from 210 seconds to 270 seconds after sampling. TEG parameters were measured at preoperation, before and after bone cement insertion (before and after reaming in the noncemented group), at postoperative 6, 24 hours in both groups. RESULTS: There were no significant changes of r, k, alpha angle, MA and Ly60 irrespective of the use of bone cement. Also, in the cemented group, there were no significant changes in TEG measurements between before and after bone cement insertion. However, there were increase in MA and alpha angle at postoperative 6 hours compared with preoperation irrespective of the use of bone cement. CONCLUSIONS: This study reveals that there are no differences between fixation with and without bone cement in the activation of the cascade systems by hip replacement arthroplasty.