Biomedical subjects

Mitsuo Ochi

Publications and source records attributed to Mitsuo Ochi.

At least 91 records · Page 5Linked to original sources

PubMed2004

Osteochondral lesion located at the lateral femoral condyle reconstructed by the transplantation of tissue-engineered cartilage in combination with a periosteum with bone block: a case report.

We report herein the successful treatment of a patient with an osteochondral defect extending to the edge of the lateral femoral condyle by transplantation of tissue-engineered cartilage made ex vivo using atelocollagen gel covered by periosteum with a bone block to reconstruct the normal contour of the femoral condyle.

Adult↗

PubMed2004

Bone formation using novel interconnected porous calcium hydroxyapatite ceramic hybridized with cultured marrow stromal stem cells derived from Green rat.

The clinical use of cultured marrow stromal stem cells (MSCs) has recently attracted attention in the field of tissue engineering. For the clinical use of the MSCs, a prominent scaffold is needed. A scaffold hybridized with MSCs is transformed into a "bioactive bone substitute," and this provides good osteoconduction. In this study, a novel calcium hydroxyapatite ceramic with an interconnected porous structure (IP-CHA) was used as a scaffold. MSCs were harvested from Green rats containing Green Fluorescent Protein (GFP), and then these hybrids were implanted into the tibias of Sprague-Dawley rats. The purposes of this study were to examine the osteogenic ability of these hybrids without coculture, and to evaluate whether the resulting bone formation originated from the grafted MSCs or the recipient's cells. The hybridized group showed excellent bone formation compared with the IP-CHA-only implant group. Observation of the implanted MSCs revealed that they survived 8 weeks after surgery, and differentiated into osteoblast-like cells, thus providing bone formation. This implantation of the MSCs/IP-CHA composite provides excellent osteoconduction, and is expected to have extensive clinical applications.

Animals↗

PubMed2004

Biomechanical analysis and quantitative analysis of bone scintigraphy on thrust plate hip prosthesis.

INTRODUCTION: To study the load distribution of the thrust plate hip prosthesis (TPP, Sulzer Medica, Baar, Switzerland) on femoral bone, a TPP insertion group and intramedullary cemented stem insertion group were prepared with the use of embalmed femoral anatomic specimens, and strain on the femoral bone induced by loading was measured. MATERIALS AND METHODS: Bone scintigraphy was performed in 26 joints which underwent total hip arthroplasty with the use of TPP, to enable quantitative evaluation of postoperative remodeling of the bone. RESULTS: In the TPP insertion group, the strain was almost equivalent to that in the untreated femoral control group. On the other hand, compared with the control group and TPP insertion group, strain in the proximal portion of the femoral bone (medial side of the femoral neck) was significantly smaller in the cemented stem group (control group versus cemented stem insertion group, p=0.0062; cemented stem insertion group versus TPP 130 degrees insertion group, p=0.0005; cemented stem insertion group versus TPP 140 degrees insertion group, p=0.0031). Bone scintigrams revealed decreased uptake at 12 weeks after operation compared with 6 weeks after operation, indicating that TPP allows earlier implant stabilization than the conventional stem. CONCLUSION: Compared with the conventional stem, TPP is a prosthesis that can perform physiological load transmission.

Aged↗

PubMed2004

Evaluation of systemic chemotherapy with magnetic liposomal doxorubicin and a dipole external electromagnet.

The development of an active drug delivery system is an attractive approach to increase the targetability of anticancer agents. In the present study, we examined the efficiency of systemic chemotherapy with small magnetic liposomes containing doxorubicin (magnetic DOX liposomes) and an externally applied electromagnetic force in osteosarcoma-bearing hamsters. Syrian male hamsters inoculated with osteosarcoma, OS515, in the limb were studied 7 days after inoculation. The efficiency of this system was evaluated by measuring the tissue distribution and tumor-suppressing effects of DOX on primary tumor growth and lung metastases. A DC dipole electromagnet was used, and the hamster's tumor-bearing limb was placed between 2 poles after the i.v. administration of liposomes. The dose of DOX and the magnetic field strength were fixed at 5 mg/kg and 0.4 T, respectively. Administration of magnetic DOX liposomes followed by 60 min application of magnetic field produced a 3- to 4-fold higher maximum DOX concentration in the tumor. This newly designed systemic chemotherapy significantly suppressed primary tumor growth for at least 2 weeks, though other DOX treatments also suppressed compared to control. Histologic examination confirmed a greater antitumor effect of this systemic chemotherapy compared to standard methods. In addition, this approach significantly suppressed lung metastases measured at 3 weeks posttreatment. These results suggest that this systemic chemotherapy can effectively reduce primary tumor growth and suppress lung metastasis due to increased targeting of DOX. Such targeted drug delivery for anticancer agents would provide clinical advantages compared to current methods.

Animals↗

PubMed2004

Wide-range visualization of compound nerve action magnetic fields in the human median and ulnar nerves from the forearm to Erb's point.

We successfully visualized the compound nerve action magnetic fields (CAFs) in the human median and ulnar nerves from the forearm to Erb's point. To observe the CAFs, we used a superconducting quantum interference device gradiometer system that was developed for human peripheral nerves. The CAFs were visualized as a quadrupole pattern consisting of leading and trailing dipoles. The CAFs propagated along the anatomical pathway and extended longitudinally in the proximal segment. The most reasonable explanation is that the peak separation in the trailing dipole appeared when the leading dipole reached the proximal segment after stimulation of the median nerve at the wrist. A temporal dispersion of the CAFs was suggested to be visualized.

Adult↗

PubMed2004

Torn discoid lateral meniscus treated using partial central meniscectomy and suture of the peripheral tear.

We present the cases of 5 patients with a torn discoid lateral meniscus treated using partial central meniscectomy in conjunction with the suture repair of the tear. The patients were 4 boys and 1 girl with a mean age of 15.4 years (range, 11 to 17). Preoperatively, all patients complained of knee pain during daily or sports activities. At the final follow-up evaluation, more than 2 years later, 4 patients' conditions were graded as excellent and 1 patient's condition was graded as fair according to Ikeuchi's grading scale. The average Lysholm score improved from 83.4 points (range, 70-90) to 95.8 points (range, 89-100) postoperatively. In the 3 patients who underwent second-look arthroscopy, complete healing was seen in 2 patients. One patient had severe degenerative changes in the meniscus; the repaired site was not united and required an additional partial meniscectomy along the tear. We believe that with the current advancement in arthroscopic meniscal repair techniques, a partial central meniscectomy in conjunction with the suture repair of the peripheral tear can be effective treatment for patients with a torn complete or incomplete discoid meniscus.

Adolescent↗

PubMed2004

Synovial cyst formation resulting from nonabsorbable meniscal repair devices for meniscal repair.

Several arthroscopic meniscal repair techniques and devices have been developed during the past decade. The Mitek Meniscal Repair System (Mitek, Ethicon, Norderstedt, Germany) is one of these devices. We report a case of synovial cyst formation after medial meniscus repair with a nonabsorbable Mitek Meniscal Repair System. The cyst in the right knee developed 5 months after the meniscus repair. After excision of the synovial cysts and removal of these devices, the mass and pain of the knee were relieved. To our knowledge, this is the first report of synovial cyst formation resulting from this device.

Adolescent↗

PubMed2004

Osteochondritis dissecans of the talus treated by the transplantation of tissue-engineered cartilage.

Management of osteochondral lesions of the joint has been difficult, because articular cartilage has a poor healing capacity as a result of its lack of vessels, nerve supply, and its isolation of systemic regulation. Although a lot of basic research and surgical treatments for cartilage repair have focused on osteochondral lesions in the knee joint, orthopedic surgeons have recently diverted their attention to osteochondral lesions in the ankle joint, partly because of the widespread introduction of arthroscopy in ankle surgery. There have been many attempts to treat articular cartilage defects in the ankle joint as well as in the knee joint. However, no treatment has achieved efficient healing with hyaline cartilage. Recently, tissue engineering technique for cartilage repair has been gaining much attention in the orthopedic field. In this study, we reported on a patient with osteochondritis dissecans of the talar dome, successfully treated by transplantation of tissue-engineered cartilage made ex vivo using atelocollagen gel and low tibial osteotomy.

Adult↗

PubMed2004

The complete type of suprapatellar plica in a professional baseball pitcher: consideration of a cause of anterior knee pain.

Abstract We report the case of a professional baseball pitcher who achieved complete relief of an anterior knee pain after resection of a complete type of suprapatellar plica under arthroscopy. The 27-year-old male professional baseball pitcher had complained of right anterior knee pain while pitching for more than 2 years. On physical examination, the mobility of his patella was limited and he complained of tenderness along the joint line of his lateral patellofemoral joint. The preoperative patellofemoral axial radiograph showed osteophyte formation on the lateral edge of the patella. On preoperative magnetic resonance imaging, a septum dividing the suprapatellar pouch was found. Arthroscopy revealed obvious cartilaginous damage on the lateral facet of the patella and facing trochlea of the femoral condyle. There was a complete type of suprapatellar plica. The suprapatellar plica seemed to be anchoring the patella, which reduced the mobility of the patella. After resecting the complete type of suprapatellar plica under arthroscopy, the mobility of the patella was improved. Because his anterior knee pain while pitching reduced rapidly postoperatively, he could return to regular baseball. We consider that the main cause of his anterior knee pain was cartilaginous damage on the patella and the trochlea, which might be accelerated by the existence of the suprapatellar plica that reduced the mobility of the patella.

Adult↗

PubMed2004

Bone lengthening for congenital differences of the hands and digits in children.

PURPOSE: We investigated the growth of bones after lengthening to evaluate the effectiveness and usefulness of bone lengthening in congenital hand deficiencies. METHODS: Bone lengthening was performed to treat congenital hand deficiencies including hypoplastic thumb, hypoplasia of the small finger, cleft hand, metacarpal synostosis, brachymetacarpia, symbrachydactyly, and amniotic band syndrome. A total of 15 patients (1-13 years old) underwent lengthening of 23 bones. The average of distraction was 10 mm. The mean follow-up period was 59 months. The length of the bones at follow-up evaluation was measured and then compared with the length of the bones immediately after lengthening. The bone growth after lengthening, the percentage of growth after lengthening, and the growth rate were compared among diagnostic groups. RESULTS: In the cases involving older patients the bone length changed little and the growth plates of these patients closed naturally soon after lengthening. In contrast, in the cases in which the patients were younger than 7 years old the lengthened bones grew continuously. The amount of bone growth was different for each disease in the younger patients. In patients with amniotic band syndrome the lengthened bones grew at the same rate as the bones in the hand. Other diagnoses such as symbrachydactyly had a different growth pattern in the hand. CONCLUSIONS: We conclude that bone lengthening is a reliable method for the correction of congenital differences of the hand. The indications for this procedure must be determined while considering the relationship between the specific disease and subsequent bone growth.

Adolescent↗

PubMed2004

Regional differences in the healing potential of the meniscus-an organ culture model to eliminate the influence of microvasculature and the synovium.

Meniscal healing is well known to be region-specific, and this is thought to be mainly due to its specific vascularity. The purpose of this study was to assess regional differences in the intrinsic healing potential of the meniscus, using an organ culture model to eliminate the influence of microvasculature and the synovium. A full-thickness circular defect, 1.5 mm in diameter, was created in the inner avascular zone in meniscal explants from rabbits. As a control, a column of 1.5 mm in diameter was removed then replanted in the area where it had been obtained (Group C). In the experimental group, a 1.5 mm-diameter meniscal graft obtained from the peripheral zone of the same specimen was implanted in the damaged area (Group T). These meniscal explants were cultured for 2, 4 or 6 weeks, and the relationship between the recipient tissue and the graft was examined using both gross and histological semiquantitative scoring. The 6-week gross-examination showed that the openings were more apparent in Group C, and the score of Group T was significantly higher than that of Group C (P=0.0152). Histologically, the healing responses after both 4 and 6 weeks of incubation were significantly better in Group T than in Group C (P=0.0237, 0.0281). These results using organ culture demonstrate that intrinsic healing potential differs even without the influence of vascular supply and the synovium, indicating that the superior healing potential in the peripheral zone may contribute to the good meniscal healing in this location.

Animals↗

PubMed2004

Anterior cruciate ligament graft impingement against the posterior cruciate ligament: diagnosis using MRI plus three-dimensional reconstruction software.

OBJECTIVE: The purpose of this study was to evaluate anterior cruciate ligament (ACL) impingement against the posterior cruciate ligament (PCL) with the knee in an extended position, which arthroscopy cannot detect. MATERIALS AND METHODS: Ten normal knees and 30 ACL-reconstructed knees were assessed using MR imaging. The three-dimensional reconstruction of the ACL, PCL, femur and tibia were carried out using commercially available three-dimensional reconstruction software. Anterior cruciate ligament impingement against the PCL was graded into three categories: Grade 1, some space between the ligaments; Grade 2, no space between the ligaments, and the reconstructed ACL ran straight; and Grade 3, the reconstructed ACL did not run straight. The angle of the reconstructed ACL against the tibial plateau was also measured. RESULTS: All normal knees were classified as Grade 1. The 30 reconstructed knees were classified as follows: Grade 1, 12 cases; Grade 2, 7 cases; and Grade 3, 11 cases. The mean angle of the Grade 3 reconstructed ACL knees was significantly more vertical against the tibia as compared with the Grade 1 knees (P<.05). The postoperative KT-2000 side-to-side difference of the Grade 3 knees (2.8+/-4.5 mm) was larger than that of the Grade 1 knees (0.2+/-1.7 mm) and Grade 2 knees (-0.6+/-2.2 mm), but no statistically significant difference could be detected between the three groups in the postoperative KT-2000 data. CONCLUSION: This method is useful to evaluate ACL impingement against PCL, which cannot be detected by conventional arthroscopy during the operation. The surgeon should pay careful attention to the coronal angle of the reconstructed ACL.

Adolescent↗

PubMed2004

Acceleration of surgical angiogenesis in necrotic bone with a single injection of fibroblast growth factor-2 (FGF-2).

The aim of this study was to accelerate angiogenesis in necrotic bone by combining vascular bundle implantation and fibroblast growth factor-2 (FGF-2) administration. Twenty-four Japanese white rabbits were evaluated in this study. A portion of a rabbit iliac crest bone was removed as a free bone graft and frozen in liquid nitrogen to ensure complete cellular necrosis. A narrow hole was created in the bone and the graft was placed in the proximal thigh. In group 1, FGF-2 was injected into the hole at a single dose of 100 microg, and the saphenous artery and its venae comitantes were passed through the hole of the bone. In group 2, injection of saline into the hole and the vascular bundle implantation was used as a control. Neovascularization around the vessel was evaluated at weeks 1 and 2 after surgery. Neovascularization was observed along the implanted vascular bundle in both groups. At both 1 and 2 weeks after surgery, the vessel density of group 1 was significantly higher than that of group 2. The average length of newly formed vessels of group 1 was also significantly longer than that of group 2 at both 1 and 2 weeks after surgery. Both the vessel density and length were greater in week 2 animals than week 1. A local single injection of FGF-2 improved surgical angiogenesis in necrotic bone in this study. As FGF-2 is recognized as a potent mitogen for a variety of mesenchymal cells, the combination of vascular bundle implantation and FGF-2 administration may contribute to the treatment of ischemic osteonecrosis.

Animals↗

PubMed2004

An early return to vigorous activity may destabilize anterior cruciate ligaments reconstructed with hamstring grafts.

OBJECTIVE: To evaluate the actual date of the return to activity and its impact on the postsurgical stability of anterior cruciate ligament reconstruction (ACLR) using hamstring grafts. DESIGN: A retrospective analysis. The time of return to activity was determined by a questionnaire at 24 to 36 months after ACLRs. SETTING: An orthopedic center. PARTICIPANTS: Fifty consecutive patients who had ACLRs using hamstring grafts 24 to 36 months earlier. INTERVENTIONS: Not applicable. Main outcome measure The time of return to activity from a questionnaire and serial KT-2000 data at 3, 6, 12, 18, and 24 months postsurgery. RESULTS: Patients were divided into 2 groups according to their KT-2000 side-to-side difference at 12, 18, and 24 months postsurgery. Group I consisted of patients whose differences were 3mm or less. Group II consisted of patients whose differences were more than 3mm. At 12 and 18 months postsurgery, significant differences were detected for the time of return to running and full-speed running. A multiple regression analysis for postsurgical stability at 24 months and the time of return to these 5 activities indicated that the time of return to full-speed running and sports activities had an effect on ACL stability. CONCLUSIONS: An early return to vigorous activities is not recommended in patients undergoing ACLRs with hamstring grafts.

Adolescent↗

PubMed2004

Interposed autologous nerve segment stimulates nerve regeneration in peripheral nerve allografts in a rat model.

The ability of autologous nerve segments interposed between allografts, to increase the total nerve-gap distance, was studied. Sciatic nerve allografts were carried out in a rat model. A 15-mm nerve gap was repaired with a 25-mm nerve graft (interposed group: allo-auto-allograft; control group: allo-allo-allograft). Cyclosporin was given for 12 weeks. Nerve regeneration was evaluated using the weight of the anterior tibial muscle and histologic, morphometric and immunohistochemical analyses at 12, 13, 14, 15, 16, 20, and 24 weeks. Nerve regeneration in the interposed group was statistically significantly better than that in the control group. The authors concluded that a nerve allograft with interposed autograft may enhance nerve regeneration in this model, because of the migration of host-derived Schwann cells into the graft from not only the proximal and distal host nerve stumps, but also the interposed autograft.

Animals↗

PubMed2004

Corrective valgus osteotomy after free vascularized fibula transfer for the treatment of osteomyelitis at the neck of the femur: case report.

Reconstruction using a free vascularized fibula was performed on a long bony defect after osteomyelitis of the proximal femur. For this type of bone defect, a double-barrel fibular graft is recommended. The authors used this procedure for a 58-year-old male who had osteomyelitis of the left proximal femur. As osteotomy through a transplanted fibula can be safely performed, abduction osteotomy should be considered when coxa vara remains after reconstruction with a free vascularized fibula transfer.

Femur Neck↗

PubMed2004

Rotational acetabular osteotomy for hip dysplasia: 61 hips followed for 8-15 years.

We operated on 54 patients (61 joints) with rotational acetabular osteotomy (RAO) due to dysplasia of the hip with pre- or early-stage osteoarthritis/arthrosis. The mean follow-up was 11 (8-15) years. The Merle d'Aubigné median score increased from 14 to 15. In 2 patients (2 joints), the score decreased from 15 to 13. Progression of arthrosis was seen in 6 joints on the radiographs at follow-up. Kaplan-Meier survivorship analysis predicted an 89% (95% confidence interval 80-99) prevention of worsening of arthrosis at 10 years. Postoperative joint congruency was a risk factor for progression of arthrosis.

Acetabulum↗

PubMed2004

Effects of transforming growth factor-beta 1 on the early stages of healing of the Achilles tendon in a rat model.

We studied the effects of transforming growth factor-beta 1 (TGF-beta 1) on the genetic expression of procollagen type I and III and its effects on structural properties in the early stages of healing in rat Achilles tendon. The Achilles tendons in 90 rats were transsected and repaired immediately. TGF-beta 1 dissolved in phosphate-buffered saline was injected locally at the repair site using two different doses, and outcomes in both groups were compared to that in the control group given phosphate-buffered saline only. Five animals in each group were killed at one, two, and four weeks postoperatively, and the healing tendon was evaluated. A dose-dependent increase in the expression of procollagen type I and III mRNA was found one week postoperatively. The failure load and stiffness of the healing tendon were increased by TGF-beta 1 at two and four weeks.

Achilles Tendon↗