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Biomedical subjects

Akio Minami

Publications and source records attributed to Akio Minami.

At least 109 records · Page 6Linked to original sources
PubMed2002

Fixation with poly-L-lactic acid screws in hip osteotomy: 68 hips followed for 18-46 months.

This study evaluated 68 consecutive hip osteotomies in 61 patients using absorbable poly-L-lactic acid screws for fixation. 47 hips underwent a rotational acetabular osteotomy, 17 hips Chiari's pelvic osteotomy, and 4 hips transtrochanteric rotational osteotomy. Cortical screws were used to transfix the osteotomized acetabulum, and cancellous screws to reattach the intraoperatively osteotomized greater trochanter. The average age at surgery was 35 (12-49) years. The mean duration of follow-up was 32 (18-46) months. All the osteotomized acetabulums united well, but 4 of 54 trochanteric osteotomies failed to unite.

Adult↗
PubMed2002

Rehabilitation after hamstring anterior cruciate ligament reconstruction.

A prospective comparative study was conducted involving 62 patients to determine the effects and limits of accelerated rehabilitation on clinical outcome. The study focused on whether aggressive rehabilitation after anterior cruciate ligament reconstruction with the doubled semitendinosus and gracilis tendon autograft results in stretching the graft. Thirty patients had postoperative rehabilitation according to the current conservative protocol, and 32 patients had rehabilitation using an accelerated regime. Each patient was evaluated subjectively and objectively 36 months or more after surgery. Concerning the side-to-side difference in the anterior laxity, 87% of the patients in the conservative rehabilitation group had 3 mm or less and 80% of the patients in the accelerated rehabilitation group had the same acceptable laxity. There was no significant difference between the two groups. Muscle torque was restored significantly earlier in the patients in the accelerated rehabilitation group than in the patients in the conservative rehabilitation group. Nine months after surgery, however, there were no significant differences in the torque between the two groups. Accelerated rehabilitation significantly increased the incidence of knee effusion during rehabilitation. This study showed that acceleration of postoperative rehabilitation could rapidly restore muscle strength without significantly compromising graft stability in anterior cruciate ligament reconstruction with the doubled hamstring tendon autograft. However, this study also showed that acceleration significantly increases the incidence of synovitis. Acceleration of postoperative rehabilitation has advantages and disadvantages for clinical outcome after anterior cruciate ligament reconstruction.

Adolescent↗
PubMed2002

Vascularized fibular graft after excision of giant-cell tumor of the distal radius: wrist arthroplasty versus partial wrist arthrodesis.

Several reconstructive procedures have been described for the complete defect of the distal radius that is created after a wide excision of a giant-cell tumor of bone, including hemiarthroplasty using the vascularized fibular head and partial wrist arthrodesis between a vascularized fibula and the scapholunate portion of the proximal carpal row. The objectives of this study are to compare clinical and radiographic results between the partial wrist arthrodesis and the wrist arthroplasty, and to discuss which procedure is superior. Four patients with giant-cell tumors involving the distal end of the radius were treated with en bloc resection and reconstruction with a free vascularized fibular graft. The wrists in two patients were reconstructed with an articular fibular head graft and the remaining two patients underwent partial wrist arthrodesis using a fibular shaft transfer. There was radiographic evidence of bone union at the host-graft junctions in all cases. In the newly reconstructed wrist joint, there was palmar subluxation of the carpal bones and degenerative changes in both patients. Local recurrence was seen in one patient. According to the functional results described by Enneking et al., the mean functional score was 67 percent. The functional scores including wrist/forearm range of motion in the cases with partial wrist arthrodesis were superior to those with wrist arthroplasty. A partial wrist arthrodesis using a vascularized fibular shaft graft appears a more useful and reliable procedure for reconstruction of the wrist after excision of the giant-cell tumor of the distal end of the radius than a wrist arthroplasty using the vascularized fibular head, although our study includes only a small number of patients.

Adult↗
PubMed2002

Factors influencing prognosis after direct repair of the flexor pollicis longus tendon: multivariate regression model analysis.

Few studies have focused on the relevance of early motion exercise on repair of the flexor pollicis longus tendon. We evaluated 29 patients with flexor pollicis longus tendon lacerations treated by direct end-to-end suture, and statistically assessed the clinical factors that influenced the results by using a multivariate logistic regression model. Association with age, vascular damage and timing of repair did not affect the results. Patients with flexor pollicis longus tendon lacerations in zone II or with the tendon stumps retracted proximally had a significantly high risk of unsatisfactory results. Postoperative passive flexion and active extension exercise using rubber bands significantly decreased the risk of unsatisfactory results in these conditions. Results of this study indicate that early postoperative motion is useful after every FPL tendon repair, particularly in patients with zone II laceration or retraction of the proximal tendon stump.

Adolescent↗
PubMed2002

Cubital tunnel syndrome associated with medial elbow Ganglia and osteoarthritis of the elbow.

BACKGROUND: Medial elbow ganglia have been reported in association with cubital tunnel syndrome. This lesion is thought to occur rarely and has not been emphasized in the literature. The purposes of the present study are to report our experience with this lesion in order to elucidate its prevalence as well as its clinical and radiographic features, to describe our operative findings, and to present the results of surgical treatment. METHODS: Four hundred and eighty-seven elbows in 472 patients were treated for cubital tunnel syndrome between 1980 and 1999. We performed a retrospective study of the thirty-eight patients who had a medial ganglion. All of the ganglia were excised, and the ulnar nerve was translocated subcutaneously. Thirty-two patients were followed for a mean of thirty-seven months. RESULTS: Medial elbow ganglion was the third most common causative factor associated with cubital tunnel syndrome, with an overall prevalence of 8%. Resting pain in the medial aspect of the elbow was reported by twenty-five of the thirty-eight patients, and a sudden onset of numbness in the ring and little fingers or of medial elbow pain without prior symptoms was reported by twenty-nine patients. The symptoms lasted two months or less in thirty-one patients. All ganglia originated from the medial aspect of the ulnohumeral joint, and radiographs of that joint showed degenerative changes in thirty-seven patients. At the time of follow-up, all measurements of sensory and motor function of the ulnar nerve had improved and no recurrence of nerve palsy was found. CONCLUSIONS: Although uncommon, medial elbow ganglia have a strong association with osteoarthritis of the elbow and can cause a relatively acute onset of cubital tunnel syndrome. A patient with cubital tunnel syndrome associated with elbow osteoarthritis who complains of medial elbow pain or severe numbness within two months after the onset of the syndrome should be strongly suspected of having a ganglion. Most ganglia are occult, and ultrasonography and magnetic resonance imaging can assist in the preoperative diagnosis. Careful excision of the ganglion performed concurrently with subcutaneous anterior transposition of the ulnar nerve can produce satisfactory results.

Adult↗
PubMed2002

Spinal cord compression by multistrand cables after solid posterior atlantoaxial fusion. Report of three cases.

The sublaminar wiring procedure has been commonly used for stabilizing the atlantoaxial complex. Multistrand braided cables were introduced in the early 1990s. In previous biomechanical studies these cables were demonstrated to be superior to monofilament wires in terms of their flexibility, mechanical strength, and fatigue-related characteristics. To the authors' knowledge, they are the first to describe clinically the occurrence of delayed spinal cord compression resulting from multistrand cables after the completion of rigid spinal arthrodesis in the upper cervical spine. Three patients underwent posterior atlantoaxial fusion in which two sublaminar multistrand cables were placed. Between 15 and 48 months postoperatively, they suffered from upper- and lower-extremity numbness as well as gait disturbance. Plain radiography and computerized tomography myelography revealed spinal cord compression caused by the sublaminar cables, although fusion was complete and physiological alignment was maintained at the fused segment. The radiographs obtained immediately after surgery demonstrated that the initial cable placement had been properly performed. The shape of the cable at the initial surgery was oval and then gradually became circular. The anterior arc of the circular shape of the cable in fact led to the spinal cord compression. Considering the mechanism of this late complication, a cable tends to spring open because of its high flexibility and becomes circular shaped even after the complete arthrodesis. When applying multistrand cables for intersegmental fixation at the atlantoaxial complex, delayed complications related to bowing of the cables is possible.

Adult↗
PubMed2002

Role of macrophage migration inhibitory factor (MIF) in peripheral nerve regeneration: anti-MIF antibody induces delay of nerve regeneration and the apoptosis of Schwann cells.

BACKGROUND: Macrophage migration inhibitory factor (MIF) is a pluripotent cytokine involved in inflammation and immune responses as well as in cell growth. Although we previously demonstrated the presence of MIF in peripheral nerves, and MIF mRNA expression was up-regulated after axotomy, the role of MIF in nerve injury and regeneration has not been evaluated. MATERIALS AND METHODS: To examine the potential role of MIF in nerve regeneration, we locally administered an anti-MIF polyclonal antibody into regenerating rat sciatic nerves using the silicone chamber model. The effect of the anti-MIF antibody on nerve regeneration was evaluated using an axonal reflex test. In addition, we carried out a terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling (TUNEL) assay and immunohistochemical analysis of the damaged nerve segments with regard to apoptosis-related proteins such as p53 to evaluate the effects of anti- MIF antibodies on apoptosis during the regeneration process. RESULTS: The regeneration length of the nerve in the anti-MIF antibody-treated group was significantly shorter than that in the non-immune rabbit IgG-treated group at weeks 2, 4 and 6 after surgery. TUNEL assay showed that a large number of apoptotic cells, mostly Schwann cells, were observed in the intratubal and distal nerve segments at weeks 4 and 6 after surgery by the anti-MIF antibody treatment. Consistent with these results, Ki-67-positive cells were significantly decreased by the anti-MIF antibody treatment. Immunohistochemical analyses revealed that p53 and, to a lesser extent, Fas were more up-regulated in the anti-MIF antibody-treated nerves than in the controls. CONCLUSION: Taken together, these results suggest that MIF plays an important role in acceleration of peripheral nerve regeneration and in prevention of Schwann cell apoptosis, mainly through overcoming the apoptotic effect of p53.

Animals↗
PubMed2001

Macrophage migration inhibitory factor up-regulates matrix metalloproteinase-9 and -13 in rat osteoblasts. Relevance to intracellular signaling pathways.

Neutral matrix metalloproteinases (MMPs) play an important role in bone matrix degradation accompanied by bone remodeling. We herein show for the first time that macrophage migration inhibitory factor (MIF) up-regulates MMP-13 (collagenase-3) mRNA of rat calvaria-derived osteoblasts. The mRNA up-regulation was seen at 3 h in response to MIF (10 microg/ml), reached the maximum level at 6-12 h, and returned to the basal level at 36 h. MMP-13 mRNA up-regulation was preceded by up-regulation of c-jun and c-fos mRNA. Tissue inhibitor of metalloproteinase (TIMP)-1 and MMP-9 (92-kDa type IV collagenase) were also up-regulated, but to a lesser extent. The MMP-13 mRNA up-regulation was significantly suppressed by genistein, herbimycin A and 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine. Similarly, a selective mitogen-activated protein kinase (MAPK) kinase (MEK)1/2 inhibitor (PD98059) and c-jun/activator protein (AP)-1 inhibitor (curcumin) suppressed MMP-13 mRNA up-regulation induced by MIF. The mRNA levels of c-jun and c-fos in response to MIF were also inhibited by PD98059. Consistent with these results, MIF stimulated phosphorylation of tyrosine, autophosphorylation of Src, activation of Ras, activation of extracellular signal-regulated kinases (ERK) 1/2, a MAPK, but not c-Jun N-terminal kinase or p38, and phosphorylation of c-Jun. Osteoblasts obtained from calvariae of newborn JunAA mice, defective in phosphorylation of c-Jun, or newborn c-Fos knockout (Fos -/- ) mice, showed much less induction of MMP-13 with the addition of MIF than osteoblasts obtained from wild-type or littermate control mice. Taken together, these results suggest that MIF increases the MMP-13 mRNA level of rat osteoblasts via the Src-related tyrosine kinase-, Ras-, ERK1/2-, and AP-1-dependent pathway.

Animals↗
PubMedDate not supplied

Rotator cuff regeneration using chitin fabric as an acellular matrix.

Twenty-one rabbits were used to investigate the feasibility of using nonwoven chitin fabric as an acellular matrix for rotator cuff regeneration. Infraspinatus tendons were cut bilaterally to create 10 x 10-mm defects. The defect in the right shoulder was covered with chitin fabric. The contralateral defect was left free as a control. The specimens were evaluated histologically and immunohistochemically at 2, 4, 8, and 12 weeks and biomechanically at 12 weeks after surgery. The acellular matrix increased cell numbers and improved collagen fiber alignment. The regenerated tissues were composed of type III collagen. The structural properties of the grafted shoulder were significantly greater than those of the control. This study revealed that using chitin fabric as an acellular matrix has advantages in enhancing both biologic and mechanical regeneration of rotator cuff tendons.

Animals↗
PubMedDate not supplied

Numerical analysis of cooperative abduction muscle forces in a human shoulder joint.

Because some shoulder muscles originate from a wide area, the modeling of such muscles has been a significant problem in a computer simulation. We demonstrated a new method of determining a vector for each of the muscles originating from a wide area. A 3-dimensional musculoskeletal model of a human shoulder was constructed from computed tomography data of a normal volunteer. Numerical analysis of 11 muscle forces and the joint reaction force during shoulder abduction from 10 degrees to 150 degrees was performed from the static equilibrium equations. An optimal origin point for the vector of the muscle with a wide origin area was determined in every analyzed position. Electromyography was carried out to validate the results of the simulation, and a significant correlation with the analyzed force was obtained in each muscle. The anatomic biomechanical model with the new muscle modeling method led to the results reflecting the actual muscle activities in a living body.

Acromioclavicular Joint↗
PubMedDate not supplied

Electromyographic analysis of internal rotational motion of the shoulder in various arm positions.

The electromyographic activity of 9 muscles of the rotator cuff and shoulder girdle was measured in 8 volunteers during active motion and isometric contraction during internal rotation of the shoulder in four positions as follows: neutral rotation with the arm at the side, neutral rotation at 90 degrees abduction in the frontal plane, the zero-position as described by Saha, and the position of the liftoff test from the midlumbar spine as described by Gerber and Krushell. The subscapularis was active at levels of about 44% maximal manual muscle test (MMT) during active internal rotation in the liftoff test position, whereas the activity of the subscapularis decreased remarkably to about 2% to 12% MMT in the other positions. The subscapular is exceptionally important as an internal rotator in the liftoff test position. During resistive motion at the zero-position, the activity level of the subscapularis (81.7%) was higher than that of other muscles. These results indicate that internal rotation at the zero-position may selectively exercise the subscapularis muscle.

Adult↗
PubMedDate not supplied

Feasibility of polysaccharide hybrid materials for scaffolds in cartilage tissue engineering: evaluation of chondrocyte adhesion to polyion complex fibers prepared from alginate and chitosan.

The ideal cell-carrier material for cartilage regeneration should be one that closely mimics the natural environment in a living articular cartilage matrix. In the current study, we considered that alginate-based chitosan hybrid biomaterials could provide excellent supports for chondrocyte adhesion. To test this hypothesis, we investigated the adhesion behavior of rabbit chondrocytes onto an alginate polymer versus the adhesion of the chondrocytes onto some alginate-based chitosan hybrid polymer fibers in vitro. We demonstrated that the alginate-based chitosan hybrid polymer fibers showed much improved adhesion capacity with chondrocytes in comparison with alginate polymer fiber. Additionally, morphologic studies revealed maintenance of the characteristic round morphology of the chondrocyte and the dense fiber of the type II collagen produced by the chondrocytes in the hybrid polymer. On the basis of these results, we conclude that an alginate-based chitosan hybrid polymer fiber has considerable potential as a desirable biomaterial for cartilage tissue scaffolds.

Alginates↗
PubMedDate not supplied

Thiolation of chitosan. Attachment of proteins via thioether formation.

Chitosan has a variety of biological functions through conjugating of other compounds to their amino and hydroxyl groups. To further expand applicability of chitosan, we have modified the amino group of chitosan with 2-iminothiolane to bestow thiol groups and obtained about 20% yield, which is equivalent to 913 microequiv SH/g chitosan or 457 nequiv SH/nmol chitosan. Bovine serum albumin (BSA) was reacted with N-(epsilon-maleimidocaproyloxy)sulfosuccinimide ester (sulfo-EMCS), and maleimide-modified BSA (MalN-BSA) was obtained. The yield of sulfo-EMCS addition was 12.8-36.8 mol MalN/mol BSA. When the chitosan-SH was reacted with MalN-BSA via thioether, 97.8% of the maleimide group was reacted, and 37.2% of the SH group was consumed. The remaining SH group was quenched by bromoacetamide. This is the first report of covalent conjugation of a protein to chitosan. Our method should find many applications in developing new chitosan-based biomedical materials containing other components such as growth factors and cell adhesion molecules, known to be crucial to cells. Our thiolated chitosan will facilitate conjugation of such biomedical components to provide new types of materials for tissue engineering.

Animals↗
PubMedDate not supplied

Treatment of congenital pseudarthrosis of the tibia: a multicenter study in Japan.

Treatment of congenital pseudarthrosis of the tibia (CPT) remains a challenge. To clarify the current situation in treatment, a multicenter study was carried out to obtain information on the results of CPT treatment. The objective of this study was to propose appropriate treatment guidelines for CPT. Records of 73 patients with CPT who underwent surgical treatment were collected from 32 hospitals. The modality of the treatment was 26 with Ilizarov technique, 25 with free vascularized fibular graft, 7 with a combination of the two techniques, 6 with intramedullary nailing with free bone grafting, 5 plating with free bone grafting, and 4 with other treatments. Fifty-four procedures resulted in union, 7 resulted in delayed union, 7 were left un-united, 1 underwent amputation, and the results were unknown in 4. According to the results of this study, the most acceptable methods of treatment of CPT are the Ilizarov method and the vascularized fibular graft.

Adolescent↗
PubMedDate not supplied

Rotational osteotomy at the diaphysis of the radius in the treatment of congenital radioulnar synostosis.

Four cases of congenital radioulnar synostosis in three patients were treated by rotational osteotomy of the distal radius. The diaphysis of the radius was osteotomized transversely, and then the forearm was supinated manually. Following surgery, the palm was immobilized in a fully supinated position by a long-arm cast. The average age at surgery was 4 years 5 months old (range 3 years 11 months to 4 years 11 months), and the average follow-up was 21 months (range 12-36 months). Bone union was obtained in all patients without any complications or correction loss. Functional improvements were achieved in all patients. This procedure is simple and safe in the treatment of congenital radioulnar synostosis.

Child, Preschool↗