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Mitsuo Ochi

Publications and source records attributed to Mitsuo Ochi.

At least 55 records · Page 3Linked to original sources
PubMed2005

Meniscal regeneration using tissue engineering with a scaffold derived from a rat meniscus and mesenchymal stromal cells derived from rat bone marrow.

The purpose of this study was to regenerate a meniscus using a scaffold from a normal meniscus and mesenchymal stromal cells derived from bone marrow (BM-MSCs). Thirty Sprague-Dawley rat menisci were excised and freeze-thawed three times with liquid nitrogen to kill the original meniscal cells. Bone marrow was aspirated from enhanced green fluorescent protein transgenic Sprague-Dawley rats. BM-MSCs were isolated, cultured for 2 weeks, and 2 x 10(5) cells were then seeded onto the meniscal scaffolds. Using a fluorescent microscope and immunohistochemical staining, repopulation of enhanced green fluorescent protein positive cells was observed in the superficial zone of the scaffold after 1 week of culture, and then in the deep zone after 2 weeks. At 4 weeks, expression of extracellular matrices was detected histologically and expression of mRNA for aggrecan and type X collagen was detected. Stiffness of the cultured tissue, assessed by the indentation stiffness test, had increased significantly after 2 weeks in culture, and approximated the stiffness of a normal meniscus. From this study, we conclude that a scaffold derived from a normal meniscus seeded with BM-MSCs can form a meniscus approximating a normal meniscus.

Animals↗
PubMed2005

Nerve tolerance to high-dose-rate brachytherapy in patients with soft tissue sarcoma: a retrospective study.

BACKGROUND: Brachytherapy, interstitial tumor bed irradiation, following conservative surgery has been shown to provide excellent local control and limb preservation in patients with soft tissue sarcomas (STS), whereas little is known about the tolerance of peripheral nerves to brachytherapy. In particular, nerve tolerance to high-dose-rate (HDR) brachytherapy has never been properly evaluated. In this study, we examined the efficacy and radiation neurotoxicity of HDR brachytherapy in patients with STS in contact with neurovascular structures. METHODS: Between 1995 and 2000, seven patients with STS involving the neurovascular bundle were treated in our institute with limb-preserving surgery, followed by fractionated HDR brachytherapy. Pathological examination demonstrated that 6 patients had high-grade lesions with five cases of negative margins and one case with positive margins, and one patient had a low-grade lesion with a negative margin. Afterloading catheters placed within the tumor bed directly upon the preserved neurovascular structures were postoperatively loaded with Iridium-192 with a total dose of 50 Gy in 6 patients. One patient received 30 Gy of HDR brachytherapy combined with 20 Gy of adjuvant external beam radiation. RESULTS: With a median follow-up of 4 years, the 5-year actuarial overall survival, disease-free survival, and local control rates were 83.3, 68.6, and 83.3%, respectively. None of the 7 patients developed HDR brachytherapy-induced peripheral neuropathy. Of 5 survivors, 3 evaluable patients had values of motor nerve conduction velocity of the preserved peripheral nerve in the normal range. CONCLUSION: In this study, there were no practical and electrophysiological findings of neurotoxicity of HDR brachytherapy. Despite the small number of patients, our encouraging results are valuable for limb-preserving surgery of unmanageable STS involving critical neurovascular structures.

Adolescent↗
PubMed2005

Clinical outcomes of 54 pelvic osteosarcomas registered by Japanese musculoskeletal oncology group.

BACKGROUND: To determine the clinical outcomes in patients with pelvic osteosarcoma, we reviewed the experience with 54 pelvic osteosarcoma patients. METHODS: Thirty-five patients underwent surgical treatment with 30 undergoing limb salvage procedures and 5 requiring hemipelvectomies. RESULTS: Oncological outcome was continuously disease free in 12 cases, no evidence of disease in 3, alive with disease in 3, died of disease in 34 and died of other causes in 2. The 5-year survival rate was 29.5%. For the patients who underwent surgery, statistically significant prognostic factors were chemotherapy, surgical margin, tumor location in sacrum, efficacy of chemotherapy, local recurrence, metastasis and treatment for metastases. With univariate analysis, local recurrence, surgical margin and tumors resected from the sacrum were significant prognostic factors for metastasis. Surgical margin, tumor resected from sacrum and metastasis were significant prognostic factors for local recurrence. With regard to postoperative functional mobility, patients with tumors resected from the sacrum exhibited poorer functional mobility when compared with other sites. CONCLUSIONS: Patients with tumors located in the sacrum had worse prognosis, and significant prognostic factor for local recurrence and metastasis. Treatment of pelvic osteosarcoma especially located in the sacrum requires new approaches and further improvements in order to ensure successful outcomes.

Adolescent↗
PubMed2005

Positive effect of posterior instrumentation after surgical posterior decompression for extensive cervicothoracic ossification of the posterior longitudinal ligament.

STUDY DESIGN: A case report of a 55-year-old patient with extensive cervicothoracic ossification of the posterior longitudinal ligament (OPLL) that was treated with posterior decompression and fusion. OBJECTIVE: To report the preventive effect of posterior instrumentation on postoperative paralysis in extensive cervicothoracic OPLL. SUMMARY OF BACKGROUND DATA: Thoracic myelopathy caused by OPLL in the thoracic spine was treated with operative decompression of the spinal cord via an anterior, posterior, or posterolateral approach. However, the lack of availability for some approaches in specific cases, as well as reports of some problems for each approach, indicates that a lack of consensus still remains regarding the choice of operative procedure. METHODS: A 55-year-old female with extensive cervicothoracic OPLL presented with progressive numbness in the both hands and a gate disturbance. Cervical laminoplasty, thoracic laminectomy, and posterior fusion were performed with electrophysiologic monitoring of the spinal cord evoked potential. RESULTS: After thoracic laminectomy, the amplitude of spinal cord evoked potential waveforms decreased but recovered after a posterior fusion by instrumentation. CONCLUSION: Prevention of postoperative paralysis from increasing by posterior instrumentation was shown using neurophysiologic monitoring.

Cervical Vertebrae↗
PubMed2005

A long-term follow-up study after medial patellofemoral ligament reconstruction using the transferred semitendinosus tendon for patellar dislocation.

The management of patellar dislocation syndrome has traditionally been difficult. There are no golden standard methods for patellar dislocations probably due to the many etiologies. However, it is known that medial patellofemoral ligament (MPFL) is damaged when the patella is dislocated. The purpose of this study is to examine whether our method of MPFL reconstruction is useful for the treatment of dislocated patellae and unstable patellae. Forty-six knees (43 patients) of 68 knees (65 patients) that were operated on using our surgical procedure for MPFL reconstruction with the advancement of the vastus medialis or the MPFL reconstruction with Insall's procedure were followed up for at least 5 years. The patient age ranged from 6 to 43 years. These knees consisted of six habitual dislocation patellae, twenty-six recurrent dislocation patellae, ten traumatic dislocation patellae, and four unstable patellae. The patients were evaluated pre-operatively and more than three times post-operatively at 6, 12, 36, 60, or 120 months. No patient experienced patellar dislocation after surgery. Their post-operative Kujala's scores were significantly improved. On conventional X-ray and on stress X-ray evaluations, the mean values for congruence angle, tilting angle, lateral shift ratio, medial stress shift ratio, and lateral stress shift ratio at the final follow-up (60 or 120 months) were demonstrated to be within the normal range. We conclude that our MPFL reconstruction method with the advancement of the vastus medialis or with Insall's procedure might be recommended for the treatment of habitual, recurrent, and indeed any other type of patellar dislocation, as well as for unstable patellae.

Adolescent↗
PubMed2005

Efficiency of magnetic liposomal transforming growth factor-beta 1 in the repair of articular cartilage defects in a rabbit model.

We evaluated the efficacy of a magnetic liposomal delivery system of transforming growth factor (TGF)-beta(1) in the treatment of articular cartilage defects in a rabbit model. Articular cartilage defects were created in the patellar groove of rabbits, and a permanent magnet or a nonmagnetic alloy was implanted in the defect site. Magnetic liposomal drugs, prepared by the conventional film method and sonication, were injected into the defect site 1 week after surgery. First, the efficacy of the magnetic liposomal delivery system was evaluated by using a model compound fluorescence-labeled dextran 40,000 (FD-40). Then, the therapeutic efficiency of magnetic liposomal TGF-beta(1) was evaluated by cartilage histological scoring at 4, 8, and 12 weeks after surgery. The injected magnetic liposomal FD-40 accumulated at the target site where a permanent magnet had been implanted. The histological score showed that the injection of magnetic liposomal TGF-beta(1) under magnetic force was significantly effective in the repair of the defect site over 12 weeks after surgery. Injection of TGF-beta(1) into the cartilage defect was effective as a magnetic liposomal preparation under magnetic force, resulting in acceleration of the cartilage repair, probably because of the desirable accumulation of TGF-beta(1) at the target site.

Animals↗
PubMed2005

Visualization of temporal increase in compound nerve action magnetic fields in the human median nerve during ischemia.

We studied the variation in the human median nerve activity during ischemia by measuring compound nerve action magnetic fields (CAFs). Temporal increases in the CAF during ischemia were successfully visualized on isofield contour maps. Intense paresthesias were induced after 29 +/- 5 s (mean +/- SD) of ischemia, which consistently reached a maximum after 4 min 55 +/- 12 s. The variations in CAFs were consistent with changes in sensory perception. The hyperexcitability in large myelinated axons can be visualized as temporary increases in CAF. These results are the first to demonstrate the efficacy of magnetic-recording techniques, which allow monitoring of changes in neural activity.

Adult↗
PubMed2005

Arthroscopic assessment for intra-articular disorders in residual ankle disability after sprain.

BACKGROUND: After ankle sprain, there can be many causes of disability, the origins of which cannot be determined using standard diagnostic tools. HYPOTHESIS: Ankle arthroscopy is a useful tool in identifying intra-articular disorders of the talocrural joint in cases of residual ankle disability after sprain. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: The authors gathered the independent diagnostic results of physical examination, standard mortise and lateral radiography, stress radiography of the talocrural joint, and magnetic resonance imaging for 72 patients with residual ankle disability lasting more than 2 months after injury (mean, 7 months after injury). They performed arthroscopic procedures and compared the double-blind results. RESULTS: In all cases, the arthroscopic results matched those of other means of diagnosis. In 14 cases, the arthroscopic approach exceeded the capabilities of the other methods. Including duplications, 39 patients (54.2%) had anterior talofibular ligament injuries, 17 patients (23.6%) had distal tibiofibular ligament injuries, 29 patients (40.3%) had osteochondral lesions, 13 patients (18%) had symptomatic os subfibulare, 3 patients (4.2%) had anterior impingement exostosis, and 3 patients (4.2%) had impingement due to abnormally fibrous bands. There were only 2 cases in which the cause of symptoms could not be detected by ankle arthroscopy, compared with 16 cases in which the cause of disability could not be detected using standard methods. In 3 cases (17.6%) of distal tibiofibular ligament injuries, 8 cases (27.6%) of osteochondral lesions, and all 3 cases (100%) of impingement of an abnormal fibrous band, ankle arthroscopy was the only method capable of diagnosing the cause of residual ankle pain after a sprain. CONCLUSION: The present results suggest that arthroscopy can be used to diagnose the cause of residual pain after an ankle sprain in most cases that are otherwise undiagnosable by clinical examination and imaging study.

Adolescent↗
PubMed2005

Neovascularization and bone regeneration by implantation of autologous bone marrow mononuclear cells.

We examined whether transplantation of autologous bone marrow mononuclear cells (BM-MNCs) can augment neovascularization and bone regeneration of bone marrow in femoral bone defects of rabbits. Gelatin microspheres containing basic fibroblast growth factor (bFGF) were prepared for the controlled release of bFGF. To evaluate the in vivo effect of implanted BM-MNCs, we created bone defects in the rabbit medial femoral condyle, and implanted into them 5 x 10(6) fluorescent-labeled autologous BM-MNCs together with gelatin microspheres containing 10 microg bFGF on an atelocollagen gel scaffold. The four experimental groups, which were Atelocollagen gel (Col), Col + 5 x 10(6) BM-MNCs, Col + 10 microg bFGF, and Col + 5 x 10(6) BM-MNCs + 10 microg bFGF, were implanted into the sites of the prepared defects using Atelocollagen gel as a scaffold. The autologous BM-MNCs expressed CD31, an endothelial lineage cell marker, and induced efficient neovascularization at the implanted site 2 weeks after implantation. Capillary density in Col + BM-MNCs + bFGF was significantly large compared with other groups. This combination also enhanced regeneration of the bone defect after 8 weeks to a significantly greater extent than either BM-MNCs or bFGF on their own. In summary, these findings demonstrate that a combination of BM-MNCs and bFGF gelatin hydrogel enhance the neovascularization and the osteoinductive ability, resulting in bone regeneration.

Animals↗
PubMed2005

Meniscal repair using bone marrow-derived mesenchymal stem cells: experimental study using green fluorescent protein transgenic rats.

Meniscal tears in the avascular zone have very limited potential to heal because of a poor blood supply. Although there have been many attempts to promote the healing potential of the torn meniscus, no established treatments have achieved sufficient meniscal healing. In this study, we evaluated the efficacy of mesenchymal stem cell transplantation as a cell source to promote meniscal healing, using cells from the green fluorescent protein (GFP) transgenic rat and organ culture model. Mesenchymal stem cells from bone marrow were isolated and expanded in monolayer culture. They were embedded in fibrin glue and were transplanted into the meniscal defects of Sprague-Dawley rats. In the control groups, the defects remained untreated, or only fibrin glue without cells was transplanted. The GFP-positive cells enabled us to detect the transplanted cells from recipient cells easily. As a result, transplanted mesenchymal stem cells could survive and proliferate in the meniscal defects in the organ culture model. They also could produce an abundant extracellular matrix stained by toluidine blue around the cells which contributed to meniscal healing in the avascular status. We could detect transplanted GFP cells under a fluorescent microscope until 8 weeks after transplantation. In a clinical situation, mesenchymal stem cell transplantation is a promising new clinical strategy for the treatment of meniscal tears in the avascular zone.

Animals↗
PubMed2005

Prevention and treatment of amputation neuroma by an atelocollagen tube in rat sciatic nerves.

To evaluate the potential of the atelocollagen tube as a cap for amputation neuromas, the histological and histochemical characteristics of the neuroma and spinal cord were compared with those following silicone capping. Four weeks after the transection of 18 rat sciatic nerves, the amputated neuroma was resected, and the nerve stump inserted into an atelocollagen or silicone tube. The histological changes in the nerve ends and c-fos expression in the dorsal horn of the fourth lumbar spinal cord were evaluated at 4 weeks postoperatively. The regenerated nerve structure in the atelocollagen or silicone tube was very thin. In contrast, a typical bulbous neuroma was observed in the control group (the nerve stump was left in place). The atelocollagen and silicone tube groups demonstrated fewer c-fos-expressed cells in the spinal cord than the controls. These results suggest that capping by an atelocollagen tube, like that by a silicone tube, might successfully prevent an amputated neuroma from forming, and suppress induced pain. The atelocollagen tube may be a promising biomaterial for the prevention or treatment of a painful amputation neuroma.

Amputation, Surgical↗
PubMed2005

Bone remodeling of a femoral head after transtrochanteric rotational osteotomy for osteonecrosis associated with slipped capital femoral epiphysis: a case report.

A rare case of a 12-year-old boy on whom a joint-preserving operation for osteonecrosis after slipped capital femoral epiphysis (SCFE) was performed, is described. Firstly, in situ pinning was performed for acute-on-chronic SCFE. However, osteonecrosis and collapse of the femoral head occurred at 7 months after surgery. Secondly, transtrochanteric rotational osteotomy (TRO) was performed against progression of the collapse of the femoral head. Eight years of X-ray observation revealed bone remodeling at the osteonecrotic region. No documentation has been reported about the potential of bone remodeling of a femoral head with osteonecrosis after SCFE. This case indicates that a joint-preserving operation such as TRO is capable of promoting bone remodeling in such circumstances.

Bone Remodeling↗
PubMed2005

Functional diagnosis using multimodal spinal cord evoked potentials in cervical myelopathy.

The electrophysiological measurement of spinal cord evoked potentials (SCEPs) has been established as a tool for diagnosing the spinal level responsible for cervical myelopathy. Only a few studies, however, employed multimodal SCEPs for this purpose. The objective of this study was to investigate the correlation between multimodal SCEPs recorded during cervical laminoplasty and magnetic resonance imaging (MRI) abnormalities in 18 patients aged 70 years and older versus 32 patients less than 65 years of age. Both the SCEPs and MRIs showed higher incidences of multiple-level cord involvement in the older group than in the younger group. Discrepancies in the spinal levels involved between the SCEPs and the MRIs were found in 12 patients (67%) for the older group and 6 patients (19%) for the younger group. The accuracy of the MR images in localizing the lesion site was significantly lower in the older group than in the younger group, indicating that MR images tend to show clinically silent cord compression in elderly patients. Because spinal cord compression can appear without functional change in elderly patients, electrophysiological evaluations with intraoperative multimodal SCEP studies are a useful addition to MRI for understanding the pathology of myelopathy.

Adult↗
PubMed2005

Natural course of the minimally symptomatic nonoperated hip in patients with bilateral hip dysplasia treated with contralateral rotational acetabular osteotomy.

BACKGROUND: The purpose of this study was to investigate the natural course of the minimally symptomatic nonoperated hip in patients with pre-osteoarthritis or early osteoarthritis in bilaterally dysplastic hips. METHODS: The material consisted of 61 patients with bilaterally dysplastic hips who underwent rotational acetabular osteotomy in their symptomatic hip and nonoperative treatment in their asymptomatic or minimally symptomatic hip. The average follow-up was 10.1 years (range 7.0-15.6 years), and the average age at the time of surgery was 38.2 years (range 20-58 years). All patients were divided into two groups by joint congruity of the nonoperated hip at surgery with rotational acetabular osteotomy. RESULTS: On radiographic assessment, 1 of the 35 pre-osteoarthritis hips had developed early osteoarthritis, and 6 of the 26 early osteoarthritis hips had progressed to advanced osteoarthritis. The Kaplan-Meier survivorship analysis for the whole group of nonoperated hips, with radiographic progression of osteoarthritis as the endpoint, predicted a 10-year survival rate of 83.7% (95% confidence interval 70%-98%). Significant differences were observed in the radiographic stage (pre- and early osteoarthritis group, P=0.015) and joint congruity (good and fair group, P=0.005). CONCLUSIONS: If the contralateral nonoperated hip has good joint congruity, minimal symptoms, and no or little radiographic change in patients with pre- or early osteoarthritis and bilateral acetabular dysplasia, the probability of radiographic progression is low.

Adult↗
PubMed2005

Serum interleukin 8 levels correlate with synovial fluid levels in patients with aseptic loosening of hip prosthesis.

Levels of inflammatory cytokines (tumor necrosis factor alpha, interleukin [IL] 6, and IL-8) in serum from patients with osteolysis on radiographs after hip arthroplasty [osteolysis(+), n = 28], patients without osteolysis after hip arthroplasty [osteolysis(-), n = 24], and nonoperated healthy subjects [controls, n = 20] were determined. In addition, cytokine levels in synovial fluid from patients undergoing revision total hip arthroplasty (n = 14) for loosening were measured and compared with each other and with the area of osteolysis on radiographs. Serum IL-6 and IL-8 levels were significantly higher in the osteolysis(+) group than in the osteolysis(-) or the control groups. Furthermore, a significant correlation was found between the serum and synovial fluid IL-8 levels and between synovial fluid IL-8 levels and the area of osteolysis in patients undergoing revision total hip arthroplasty. Therefore, serum IL-8 levels could be a useful periprosthetic osteolysis marker.

Female↗
PubMed2005

The HU knot: a new sliding knot for arthroscopic surgery.

Sliding knots are commonly used in arthroscopic knot tying. The Surgical knot as a hand-tied knot is very secure. We found that the Surgical knot could be used as a sliding knot. We have modified the Surgical knot to include a self-locking loop. A new sliding knot for arthroscopic surgery, the HU knot, is described. By tensioning the loop strand, the self-locking loop creates a snug knot without sliding backward. The HU knot provides great security.

Arthroscopy↗
PubMed2005

Repair of osteochondral defect with tissue-engineered chondral plug in a rabbit model.

PURPOSE: The purpose of this study was to evaluate the macroscopic and histologic results of transplanting a tissue-engineered chondral plug made of atelocollagen sponge and PLLA mesh to treat osteochondral defects. TYPE OF STUDY: Controlled experimental study. METHODS: Twelve-week-old male Japanese white rabbits were used. Fresh articular cartilage slices were taken from the humeral head, and isolated chondrocytes were embedded in atelocollagen gel which does not have antigenic portions of collagen (2.0 x 10(6) cells/mL). They were seeded on the top of the atelocollagen sponge/PLLA mesh composite and cultured for 2 weeks. The culture medium was changed every 3 days and L-ascorbic acid (50 microg/mL) was added every 2 days. Culturing the composites for 2 weeks produced tissue-engineered chondral plugs. These tissue-engineered chondral plugs (4-mm diameter, 4-mm thick) were transplanted into the osteochondral defects (4 mm diameter, 4 mm deep) in the patellar grooves of the same rabbits from which the chondrocytes had been harvested (the experimental group). In the control group, the defects were treated with the plugs without chondrocytes. The rabbits were killed 4 and 12 weeks after transplantation. The repaired tissues were evaluated macroscopically and histologically, and analyzed immunohistochemically for expression of type II collagen. RESULTS: Four weeks after transplantation in the experimental group, the defects were partially repaired with cartilage-like tissue with good subchondral bone formation. Twelve weeks after transplantation, the defects were repaired with hyaline cartilage-like tissue densely stained by Safranin O. Well-organized subchondral bone formation was also observed. In the control group, the defects were covered with only soft fibrous tissue at 4 and 12 weeks macroscopically. Immunohistochemically, type II collagen was detected in about 90% of the repaired area. Histologic scores in the experimental group were significantly higher than those in the control group at both 4 and 12 weeks after transplantation. CONCLUSIONS: This study shows that the defects treated with tissue engineered chondral plug developed type II collagen in about 90% of the repaired area. CLINICAL RELEVANCE: The transplantation of a tissue-engineered chondral plug will be one option for treating osteochondral defects. The next step in testing our hypothesis is to evaluate the repaired tissue biomechanically and biochemically over a longer period of time.

Animals↗