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Biomedical subjects

Keiichi Muramatsu

Publications and source records attributed to Keiichi Muramatsu.

8 recordsLinked to original sources
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

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↗
PubMed2003

Recalcitrant posttraumatic nonunion of the humerus: 23 patients reconstructed with vascularized bone graft.

We treated 23 patients with recalcitrant posttraumatic humeral shaft nonunion with vascularized bone grafts (fibula 10, femur 10 and scapula 3). 21/23 patients healed primarily. Venous thrombosis in the graft necessitated postoperative thrombectomy in 2 patients. Complications at the donor site were trivial. We used a vascularized fibular graft in patients with a large bone defect and with poor intrinsic stability of the nonunion site and a corticoperiosteal femoral graft in atrophic nonunion without a substantial bone defect. The scapula graft is easy to transfer to the surgical neck of the humerus on its pedicle.

Adult↗
PubMed2003

Fate of donor cells in vascularized bone grafts: identification of systemic chimerism by the polymerase chain reaction.

Systemic chimerism, or the movement of cells from a transplanted tissue into host organs, is a phenomenon known to occur in association with development of immunological tolerance in allotransplantation. However, little is known about the fate and movement of cells into or out of autogenous free tissue transfers, including vascularized bone grafts. The purpose of this study was to identify systemic chimerism in vascularized bone grafts by transplantation of a vascularized tibiofibular graft from isogenous (inbred) male Lewis rats to female recipients. 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, 12, 18, and 24 weeks after transplantation. Competitive polymerase chain reaction study using the specific primers for a Y-chromosome marker ( gene) and an autosomal gene (GAPDH) allowed detection of small amounts of male cells in a large pool of female cells and measurement of their relative proportions as a function of time. Of 19 nonimmunosuppressed recipients, nine animals (47 percent) showed low-level chimerism (<0.1 percent) in the peripheral blood. Nine (47 percent), three (16 percent), and two (11 percent) recipients showed high-level chimerism (>1 percent) in the spleen, liver, and thymus, respectively, at final assessment. Donor cells were detected in all bone grafts and in six contralateral tibial bones (i.e., 67 percent of sampled contralateral tibial bones) at 18 and 24 weeks after transplantation. Twenty-four recipients were immunosuppressed with FK506 (tacrolimus) to suppress reaction to a minor histocompatibility barrier present on the Y chromosome. In this group, 14 animals (58 percent) showed low-level chimerism in peripheral blood and 12 (50 percent), eight (33 percent), and one (4 percent) recipients showed high-level chimerism in the spleen, thymus, and liver, respectively. Transplanted cells were detected in nine contralateral tibial bones (i.e., 60 percent of sampled contralateral tibial bones) at 12 and 18 weeks after surgery. The results indicate that polymerase chain reaction for the Y chromosome is a useful tool for differentiating between donor and recipient cell populations experimentally using sex-mismatched tissues in a rat model. This study demonstrated that systemic chimerism occurs after successful vascularized bone transplantation. Transplanted cells not only survive in the graft but also gradually migrate into the recipient's body.

Animals↗
PubMed2003

Pedicle or free musculocutaneous flaps for shoulder defects after oncological resection.

Management of soft-tissue defects of the shoulder is described. Extensive defects of soft tissues with or without overlying skin were created after resection of sarcomas in five patients. Reconstruction was performed using musculocutaneous flaps, which included three pedicle latissimus dorsi and two free tensor fascia lata flaps. Simultaneous functioning replacement of the defects of the trapezius and deltoid muscles were each achieved in two patients. Primary wound healing was achieved, and each patient recovered good contour of the shoulder. Functional results were satisfactory in all patients with an average score of 93.4% (range, 83%-100%) using the system of the Musculoskeletal Tumor Society. The four functioning muscles recovered active contraction in the transferred position. The shoulder elevation was normal in three patients, and was 90 degrees and 30 degrees in one patient each. All patients remained disease-free at the time of latest follow-up. Thus, shoulder defects of the soft tissues can be managed appropriately with the two representative musculocutaneous flaps.

Adolescent↗
PubMed2002

Scaphoid fracture in the young athlete--therapeutic outcome of internal fixation using the Herbert screw.

BACKGROUND: A fractured scaphoid is a common disabling injury occurring in contact sports. This study was designed to evaluate the therapeutic outcome of Herbert screw fixation for scaphoid fracture in young athletes. METHODS: Thirty athletes with 30 scaphoid fractures were treated. According to the Herbert classification, 10 were classified as acute fracture (group I), 6 as fibrous union (group II) and 14 as pseudoarthrosis (group III). Twenty scaphoid non-unions were due to missed diagnosis or unsuccessful immobilisation. RESULTS: Bony union was evident at an average of 9.2, 8.0 and 11.9 weeks postoperatively in groups I, II and III, respectively, and times for returning to sports were 10.7, 14.0 and 22.9 weeks. The clinical outcome assessed using the Mayo wrist score was excellent in groups I (97.5 points) and II (93.3) and good in group III (85.4). CONCLUSION: Early definitive diagnosis and treatment can allow early return to sports in young athletes. The Herbert screw technique produces an excellent clinical result for scaphoid fracture.

Adolescent↗
PubMed2002

Cell repopulation in vascularized bone grafts.

Following vascularized bone autografts, osteocyte viability is largely maintained. Viable cells within a graft may be surviving graft-derived cells, their progeny, or host-derived cells from circulation or surrounding bone. This study was conducted to define the process of cell repopulation, within vascularized bone grafts. Using inbred Lewis rats, 30 female vascularized tibial bones were transplanted to syngeneic male recipients and 45 male grafts were transplanted to female recipients. Twenty-five female recipients were immunosuppressed with FK506 to prevent rejection caused by Y-chromosome related antigens. The grafts were assessed up to 24 weeks post-transplant by radiography, histology and semi-quantitative polymerase chain reaction (PCR) using both Y-chromosome and autosome gene-specific primers. The female to male isograft transplants were useful to measure low levels of repopulation with host-derived cells, while male to female transplants more accurately quantified higher levels of cellular replacement. No host-derived cells were detected in the transplanted bone before six weeks. Thereafter, the ratio of host-derived cells gradually increased. By 24 weeks only 0.1-1.0% of graft-derived cells remained in the transplanted tibias. This study demonstrates that Y-chromosome-specific PCR is a useful tool to detect the cell lineage and cell repopulation following rat sex-mismatch vascularized bone grafting. Our results showed that donor cells in vascularized bone grafts were gradually repopulated with recipient cells. Correlation with histologic findings suggests that the periosteal hypertrophy observed by six weeks post-transplant results from graft-derived cells, while later remodeling is associated with host-derived cells.

Animals↗