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Biomedical subjects

Koichiro Ihara

Publications and source records attributed to Koichiro Ihara.

At least 19 recordsLinked to original sources
PubMed2005

Free vascularized fibula grafting for reconstruction of the wrist following wide tumor excision.

Free vascularized fibula transfer is an established method for reconstruction of the wrist following tumor resection. In cases of resection of the radial articular surface, three reconstructive options are possible: fibular head transfer along with the shaft to replace the radial joint surface, fixation of the fibula to the scaphoid and lunate, or a complete wrist fusion. Three patients with a tumor involving the distal end of the radius were treated with wide resection, and subsequent wrist reconstruction was performed, using the above-mentioned procedures. Although our experience included only a small number of patients, both radio-carpal hemiarthroplasty and fibulo-scapho-lunate fusion similarly provided successful wrist stability and functional range of motion in these cases. Even when the wrist was totally fused with the fibula, its function was still acceptable.

Adolescent↗
PubMed2005

Alternating sequential chemotherapy with high-dose ifosfamide and doxorubicin/cyclophosphamide for adult non-small round cell soft tissue sarcomas.

Doxorubicin and ifosfamide are the two most active agents used to treat soft tissue sarcomas. However, because of their overlapping side effects, concurrent administration to achieve optimal doses of each agent is difficult. We therefore conducted a Phase II trial to investigate the efficacy and feasibility of a novel alternating sequential chemotherapy regimen consisting of high dose ifosfamide and doxorubicin/cyclophosphamide in advanced adult non-small round cell soft tissue sarcomas. Adult patients with non-small round cell soft tissue sarcomas were enrolled. The treatment consisted of four sequential courses of chemotherapy that was planned for every 3 weeks. Cycles 1 and 3 consisted of ifosfamide (14 g/m(2)), and cycles 2 and 4 consisted of doxorubicin (60 mg/m(2)) and cyclophosphamide (1200 mg/m(2)). Forty-two patients (median age 47 years) were enrolled. Of the 36 assessable patients, 1 complete response and 16 partial responses were observed, for a response rate of 47.2%. Responses were observed in 57% of patients who had received no previous chemotherapy and 13% of those who had previously undergone chemotherapy. Grade 3-4 neutropenia was observed during 70% of all cycles. Sequential administration of high-dose ifosfamide and doxorubicin/cyclophosphamide has promising activity with manageable side effects in patients with advanced adult non-small round cell soft tissue sarcomas.

Adult↗
PubMed2005

Donor cell engraftment in recipient lymphoid tissues after rat limb allograft.

BACKGROUND: The movement of cells from a transplanted tissue into the host organs, the so-called systemic chimerism, is a phenomenon known to occur and be associated with the development of immunologic tolerance in allotransplantation cases. The purpose of this study was to identify donor cell engraftment in recipient lymphoid tissues after performing rat hind limb allograft. MATERIALS AND METHODS: Fifty-five whole-limb allotransplantations were performed in sex-mismatched pairs of rats. Syngeneic male Lewis and allogeneic Dark Agouti donors were transplanted to female Lewis recipients. FK506 was used for immunosuppression. Donor male cells could be identified in the recipient female tissues by semiquantitative polymerase chain reaction analysis for a Y chromosome-specific DNA sequence. Chimerism was assessed at 1, 24, and 48 weeks after transplantation. RESULTS: There was no rejection episode in any of the limb grafts. Although levels of chimerism were highly variable in each lymphoid tissue, a gradual increase was noticed in all during the course of time. At 1 week after the transplant period, only intrasplenic chimerism was at high level (1%) in three groups. At 48 weeks after the transplant, all recipients with allografts showed very high level (10%) of chimerism in the bone marrow. Two, two, and two of six recipients showed very high levels in the spleen, lymph node, and liver, respectively, at 48 weeks. Intrathymic chimerism was higher at 24 weeks after transplant rather than at 48 weeks. CONCLUSION: We demonstrated donor cell engraftment into recipient lymphoid tissues after successful whole limb transplantation. We conclude that limb allograft can work as a vascularized carrier for the bone marrow transplantation, provide a continuous source of donor cells and contribute to chimerism in the recipient.

Animals↗
PubMed2004

A giant rheumatoid nodule.

Subcutaneous rheumatoid nodules occur commonly in advanced cases of rheumatoid arthritis and are the most common extra-articular lesion of this disease. We present a case of a very unusual giant rheumatoid nodule that developed on the lateral side of a knee. The case was devoid of systemic symptoms of arthritis and the lesion was limited to a rheumatoid nodule. The nodule was successfully treated by surgical excision. However, other new nodules developed in her hand. Her clinical course has not been satisfactory.

Aged↗
PubMed2004

Microvascular anastomosis through the tibial tunnel: a new technique in free-tissue transfer to the leg.

Free-tissue transfer to a severely traumatized leg has a high rate of vascular complications. We present three successful cases using a new technique of microvascular anastomosis through the tibial tunnel. Because of the unavailability of anterior tibial artery due to posttraumatic vascular disease, donor vascular pedicles were passed posterior to the tibia through the tibial tunnel and anastomosed to the posterior tibial artery or its branch in an end-to-end fashion. The flaps survived perfectly, without any vascular complication. This technique represents a safe route, and the shortest route, to an expected anastomosis point. Our technique is indicated especially in cases with a single-vessel leg.

Adult↗
PubMed2004

Effects of cessation of immunosuppression on skeleton reconstructed by vascularized bone allograft in rats.

In the present study, we investigated the effects of cessation of immunosuppression on skeleton reconstructed by vascularized allogenic bone transplantation in a rat tibio-fibula graft model. Twelve-week-old male 25 Dark Agouti rats with the major histocompatibility antigen (MHC) RT1a were used as donors and age-matched male 25 Lewis rats with MHC RT1l were used as recipients. Among them, 20 rats were randomly allocated to 8-week cyclosporine A (CsA) followed by 8-week CsA vehicle group or continuous 16-week CsA group. The remaining 5 rats received CsA for 8 weeks followed by no further treatment for next 40 weeks (long-term observation group). In the CsA followed by vehicle group as well as the continuous CsA group, the structure of the reconstructed bones was maintained, though the transplanted bones in former group were found to be partly non-vital. The CsA followed by vehicle group had higher bone mineral density of the transplanted bones and stronger strength of the reconstructed bones than the continuous CsA group. In the long-term observation group, the structure of the reconstructed bones was still maintained and the transplanted bones were almost vital. These results suggest that long-term strong immunosuppression may not be necessary for successful reconstruction of large bone defect by vascularized bone allograft.

Absorptiometry, Photon↗
PubMed2004

Role of vascularised tissue transfer after oncological resection in the upper extremity.

We reviewed 12 patients who had had vascularised tissue transfer after oncological resection in the upper extremity. All patients had immediate reconstruction, and one had a double tissue transfer. Tissues used were skin flaps, free muscles, and vascularised fibulas, for resurfacing the wound, motor recovery, and reconstruction of large bony defects, respectively. All the patients returned early to their daily activities. Although local recurrences were encountered in two patients, they were again rendered disease-free by salvage operations. Two patients had secondary reconstructions using pedicle latissimus dorsi flaps for late problems, including one of the two patients who developed a local recurrence. The mean functional score using the system devised by the Musculoskeletal Tumor Society was 84%. All the upper extremities were successfully rescued with satisfactory function. Vascularised tissue transfer was invaluable for achieving both curative resection of the tumour and a useful upper extremity.

Adolescent↗
PubMed2004

Posttraumatic radioulnar synostosis treated with a free vascularized fat transplant and dynamic splint: a report of two cases.

Two cases of posttraumatic radioulnar synostosis are presented. The patients were treated with excision of the cross-union and interposition of a free vascularized fat transplant. A newly devised pronation-supination dynamic splint was employed for 3 months postoperatively in both patients. After a 1-year postoperative follow-up, an increased range of motion was restored in both cases, and there was no evidence of recurrent synostosis formation in subsequent radiographs. We suggest that an interposed vascularized fat graft may be an ideal biologic barrier to fill the space created by cross-union excision.

Adult↗
PubMed2004

Fabrication of a maxillofacial prosthesis using a computer-aided design and manufacturing system.

PURPOSE: Maxillofacial prostheses are usually fabricated on the basis of impressions made with dental-impression material. The extent to which the prosthesis reproduces normal facial morphology depends on the clinical judgment of the individual fabricating the prosthesis. This paper describes a computer-aided design and manufacturing (CAD/CAM) system for the fabrication of maxillofacial prostheses. This system will provide a more consistently accurate reproduction of facial morphology. MATERIALS AND METHODS: Facial measurements were taken using a non-contact three-dimensional laser morphological measurement system. The measurements were sent to a computer numerical controlled (CNC) milling machine to generate a cast of the patient's face for the fabrication of prosthesis. RESULTS: Facial contours were measured using a laser. This method minimizes patient discomfort and avoids soft tissue distortion by impression material. Moreover, the digital data obtained is easy to store and transmit, and mirror-images can be readily generated by computer processing. CONCLUSION: This method offers an objective, quantified approach for fabricating maxillofacial prostheses.

Computer-Aided Design↗
PubMed2003

Skeletal reconstruction by vascularized allogenic bone transplantation: effects of statin in rats.

BACKGROUND: Some statins have been reported to suppress the immune system and increase the expression of bone morphogenetic protein-2 gene that plays a pivotal role in bone regeneration. METHODS: The effects of cerivastatin on skeletal reconstruction by vascularized bone allograft were investigated in a rat tibia-fibula graft model. After transplantation, the recipient rats were treated with vehicle, low-dose cerivastatin, high-dose cerivastatin, or cyclosporine A. RESULTS: Transplanted bones treated with low-dose cerivastatin and vehicle failed to unite with the recipient bones. In contrast, high-dose cerivastatin induced the bone union as effectively as cyclosporine A. Histologically, high-dose cerivastatin-treated transplanted bones were nonvital, but new bone formation occurred at the outer layer of the nonvital cortex. CONCLUSION: These results indicate that statins could promote fracture healing. Because transplant recipients have the increased risks of osteoporotic fracture and hypercholesterolemia, statins may be a good choice in the treatment of these patients.

Animals↗
PubMed2003

Ulnar variance and the role of joint levelling procedure for Kienböck's disease.

Forty patients with Kienböck's disease were reviewed to determine the relationship between ulnar variance and the development of Kienböck's disease in a Japanese cohort. The joint levelling procedures designed to correct ulnar variance were evaluated in 11 patients after a mean of 9.7 years following surgery. The mean ulnar variance was 0.50+/-1.67 in patients with Kienböck's disease and 0.56+/-1.76 in a control group. The onset of wrist symptoms in a younger age group was noticed after sports injuries, whereas older patients had no distinct history of trauma. Joint levelling procedures produced good clinical results, but carpal height ratio, Stahl's index and radioscaphoid angle were not improved, as evidenced radiographically. Our study suggests that in a Japanese cohort ulnar minus variance is not an important factor in the aetiology of Kienböck's disease. Although joint levelling procedures improved the clinical results, they did not reverse lunate collapse or carpal alignment.

Adolescent↗
PubMed2003

Patellar tendon rupture and marked joint instability after total knee arthroplasty.

BACKGROUND: Patellar tendon rupture is a rare complication of total knee arthroplasty (TKA). Multiple repair methods have been described in the literature. METHODS: A 66-year-old woman suffered a patellar tendon re-rupture and marked joint instability within 6 months after revision TKA. She underwent re-revision TKA and extensor mechanism reconstruction with femoral quadriceps tendon and augmentation by a Leeds-Keio ligament. RESULT: It was fairly difficult to acquire a satisfactory range of motion as well as gain in knee extension capacity by eliminating the extension lag. CONCLUSION: Patellar tendon ruptures after TKA should be repaired as soon as they are recognized.

Aged↗
PubMed2003

Carpal instability in rheumatoid wrists.

This study was conducted to identify patterns of carpal instability in the rheumatoid wrist. One hundred patients with proven rheumatoid arthritis were randomly chosen, and posteroanterior and lateral radiographs of right wrists were taken. The most common isolated pattern was volar intercalated segmental instability, apparent in 16 wrists, while nine wrists had scapholunate dissociations. Larsen grading scores revealed a correlation between disease duration, carpal height ratio, and ulnar translocation index. In the early stages of disease, the scapholunate angle was significantly increased and the lunate rotated volarly due to loosening of the intrinsic carpal ligament. In later phases, the capitolunate angle significantly increased and the capitate rotated dorsally. Patterns of carpal instability in rheumatoid wrists seem to be complicated, involving combined laxity of the intrinsic and extrinsic carpal ligaments.

Adult↗
PubMed2003

Behavior of male-specific minor histocompatibility antigen in skin and limb transplantation.

BACKGROUND: Although the role of male-specific minor histocompatibility antigen H-Y has been increasingly understood in both experimental and clinical organ transplantation, little has been investigated on musculoskeletal tissue transplantation. This study was performed to describe the behavior of male-specific minor histocompatibility H-Y antigen in rat skin and whole limb transplantation. MATERIALS AND METHODS: Using three different strains of inbred rats (Lewis, F344, and Dark Agouti), 75 donor hindlimbs and eighteen skin grafts were isogenically transplanted to the sex-mismatched recipients. Recipients were observed up to 48 weeks postoperatively. Rejection was monitored by the appearance of the skin of the grafted limb and histology. Systemic microchimerism was assessed by polymerase chain reaction using Y-chromosome specific primers. RESULTS: Skin rejection didn't occur in all limb transplant recipients and histology did not show any rejection findings in all components of the limb graft through 48 weeks. Successful functional recovery was expected. Stable and high level of chimerism (>1%) was detected in the lymphoid tissues in nontreated female recipients. Male skin grafts were rejected by Lewis and F344 female recipients within 6 weeks postoperatively. All female skin grafts survived in male recipients. CONCLUSION: Our results suggest that H-Y antigen can induce graft rejection in rat skin graft but causes no rejection reaction in whole limb transplantation. Systemic chimerism may play an important role for acceptance of sex-mismatched limb graft.

Animals↗
PubMed2003

Meniscal ossification.

Meniscal ossicles are rare in the human knee. We present one case. A 57-year-old taxi driver complained of right knee pain and swelling with radiographic findings of a meniscal ossicle. Arthroscopic inspection showed a degenerative and horizontal tear and calcium deposit at the middle and posterior thirds of lateral discoid meniscus. His lateral discoid meniscus, containing the ossicle, was removed. He was asymptomatic at a 3-year follow-up.

Arthralgia↗
PubMed2003

Snapping knee caused by intra-articular tumors.

Locking of the knee can present with no history of antecedent injury. We identified impingement of intra-articular tumors in 2 cases. Intra-articular tumors are relatively rare. Mechanical symptoms were present in both cases. On physical examination, there was a palpable mass at the medial region of the patellofemoral joint. The interior had been replaced mainly by amorphous necrotic tissue. The definite diagnosis of a soft-tissue mass of the knee could not be made on histologic examination.

Adipose Tissue↗
PubMed2003

Atypical palmar fibromatosis with giant fibrous nodule: a case report.

We present an unusual case of palmar fibromatosis. A 62-year-old man had a giant fibrous nodule in the deep fascia of the right palm without any pretendinous cord or flexion deformity at the metacarpophalangeal joint. Primarily soft-tissue tumor and palmar fibromatosis were considered as differential diagnosis of nodular mass but finally the latter was confirmed histologically after resection of the giant nodule.

Diagnosis, Differential↗