Biomedical subjects

Akio Minami

Publications and source records attributed to Akio Minami.

At least 19 recordsLinked to original sources

PubMed2007

Effect of pore size on in vitro cartilage formation using chitosan-based hyaluronic acid hybrid polymer fibers.

In this study, we successfully developed three-dimensional scaffolds fabricated from the chitosan-based hyaluronic acid hybrid polymer fibers, which can control the porous structure. To determine the adequate pore size for enhancing the chondrogenesis of cultured cells, we compared the behaviors of rabbit chondrocytes in scaffolds comprising different pore sizes (100, 200, and 400 microm pore size). Regarding the cell proliferation, there was no significant difference among the three groups. On the other hand, glycosaminoglycan contents in the 400 microm group significantly increased during the culture period, compared with those in the other groups. The ratio of type II to type I collagen mRNA level was also significantly higher in the 400 microm group than in the other groups. These results indicate that our scaffold with 400 microm pore size significantly enhances the extracellular matrix synthesis by chondrocytes. Additionally, the current scaffolds showed high mechanical properties, compared with liquid and gel materials. The data derived from this study suggest great promise for the future of a novel fabricated material with relatively large pore size as a scaffold for cartilage regeneration. The biological and mechanical advantages presented here will make it possible to apply our scaffold to relatively wide cartilaginous lesions.

Animals↗

PubMed2007

Clinical outcome of posterolateral endoscopic surgery for pyogenic spondylodiscitis: results of 15 patients with serious comorbid conditions.

STUDY DESIGN: Clinical results of posterolateral endoscopic debridement and irrigation followed by percutaneous drainage for pyogenic spondylodiscitis were analyzed. OBJECTIVES: To report clinical results of transforaminal endoscopic surgery for pyogenic spondylodiscitis and to evaluate the effectiveness of this procedure in treatment of pyogenic spinal infections. SUMMARY OF BACKGROUND DATA: Pyogenic spinal infections have been increasing due to the development of medical treatment for patients with comorbid medical problems. Common treatments for spinal infections are administration of antibiotics or surgical debridement with bone grafts. There have been no reports, however, regarding the clinical outcome of posterolateral endoscopic treatment for pyogenic spinal infections. METHODS: Fifteen consecutive patients with pyogenic spondylodiscitis in the thoracic or lumbar spine were enrolled. Preoperative antibiotic treatment had failed in all the patients. The procedures consisted of posterolateral endoscopic debridement and irrigation followed by percutaneous drainage through single portal under the combination of local and intravenous anesthesia. Pain response using visual analog scale (VAS, 0-100 mm), inflammation parameters, and duration of antibiotic therapy were investigated. Radiologic evaluation focused on bony fusion, local kyphosis, disc height reduction, and abscess formation. RESULTS: All patients showed immediate pain reduction after surgery. Averaged VAS for pain was 86 before surgery and 25 at postoperative 1 week. Average of CRP was 4.00 mg/dL before surgery and 1.88 mg/dL at postoperative 1 week. Averaged duration of antibiotics therapy was 3.7 weeks. Spinal fusion was obtained in 13 patients. Two patients with neurologic deficits due to epidural abscess returned to normal. Preoperative psoas abscess in 6 patients disappeared after surgery on MRI. CONCLUSIONS: Posterolateral spinal endoscopic debridement and irrigation brought immediate pain reduction and good clinical results to patients who had comorbid medical problems and had pyogenic spondylodiscitis.

Adolescent↗

PubMed2007

Identification of CLUAP1 as a human osteosarcoma tumor-associated antigen recognized by the humoral immune system.

Since the prognosis of human osteosarcoma in advanced stage remains poor, the development of new and effective therapies including immunotherapy is required. To identify tumor-associated antigens of osteosarcoma applicable to the immunotherapy of this malignancy, we employed the serological analysis of recombinant cDNA expression library (SEREX) technique that defines tumor antigens recognized by the humoral immune system. Screening a cDNA library derived from an osteosarcoma cell line MG63 with sera from osteosarcoma patients identified 43 positive clones, representing 14 distinct antigens. Among them, CLUAP1 (clusterin-associated protein 1) was highly expressed in osteosarcoma tissue samples and cell lines. Overexpression of CLUAP1 was observed in other malignancies including ovarian, colon, and lung cancers. Our results suggest that CLUAP1 may be useful as a prognostic/diagnostic marker and/or for a target of immunotherapy of osteosarcoma.

Adolescent↗

PubMed2006

Massive rotator cuff tears repaired on top of humeral head by McLaughlin's procedure.

The clinical and radiographic outcomes of McLaughlin's procedure for massive rotator cuff tears were investigated in 25 shoulders, in which the cuff tears were so severe that the tendons were sutured on the top of the humeral head. The mean age at surgery was 62.2 years (range, 39-74 years). The mean follow-up period was 50 months (range, 24-80 months). The University of California, Los Angeles score significantly improved from 10.9 to 31.8 points postoperatively; the postoperative result was classified as excellent in 11 shoulders, good in 11, and poor in 3. Osteoarthritis progressed postoperatively in 7 shoulders (28%), and upper migration of the humeral head progressed in 6 (24%), although both progression rates were no higher than those for other common procedures. When torn tendons reach over the top of the humeral head with the arm at the side in patients with massive tears that are not reparable to the greater tuberosity, satisfactory clinical outcomes can be expected.

Adult↗

PubMed2006

Activity-dependent regulation of BRINP family genes.

We previously identified a family of novel developmentally regulated genes: BRINP1, 2, and 3, which are predominantly and widely expressed in the CNS from earlier developmental stages to adulthood. In the present study, we investigated the activity-dependent regulation of BRINP expression in the CNS. Among the three BRINP genes, BRINP1-mRNA was specifically up-regulated in the dentate gyrus of mouse hippocampus by kainic acid treatment. In cultured hippocampal neurons, the induction of BRINP1-mRNA was also observed by the activation of glutamate receptors. Although BDNF-mRNA is up-regulated in a similar activity-dependent manner, BDNF itself did not induce BRINP1-mRNA. From these results, the physiological roles of the activity-dependent induction of BRINP1-mRNA are discussed.

Animals↗

PubMed2006

The role of osteopontin in tendon tissue remodeling after denervation-induced mechanical stress deprivation.

It has been shown that musculoskeletal tissues undergo dynamic tissue remodeling by a process that is quite sensitive to the mechanical environment. However, the detailed molecular mechanism underlying this process remains unclear. We demonstrate here that after denervation-induced mechanical stress deprivation, tendons undergo dynamic tissue remodeling as evidenced by a significant reduction of the collagen fibril diameter. Importantly, the transient up-regulation of osteopontin (OPN) expression was characteristic during the early phase of tendon tissue remodeling. Following this dynamic change of OPN expression, matrix metalloproteinase (MMP)-13 expression was induced, which presumably accounts for the morphological changes of tendon by degrading tendon collagen fibrils. The modulation of MMP-13 expression by OPN was specific, since the expression of MMP-2, which is also known to be involved in tissue remodeling, did not alter in the tendons under the absence or presence of OPN. We also demonstrate that the modulation of MMP-13 expression by OPN is due to the signaling through cell surface receptors for OPN. Thus, we conclude that OPN plays a crucial role in conveying the effect of denervation-induced mechanical stress deprivation to the tendon fibroblasts to degrade the extracellular matrices by regulating MMP-13 expression in tendon fibroblasts.

Animals↗

PubMed2006

The effect of intraosseous graft length on tendon-bone healing in anterior cruciate ligament reconstruction using flexor tendon.

The current study was performed to understand the relationship between graft length placed within the bone tunnel and intraosseous graft healing in anterior cruciate ligament (ACL) reconstruction. Twenty-four adult beagle dogs were divided into two groups of 12 animals each. In each animal, ACL reconstruction using a 4-mm diameter autogenous flexor tendon graft was done in the left knee. In groups I and II, the graft having a length of 15 and 5 mm, respectively, was placed within the tibial tunnel. The proximal end of the graft was placed through the over-the-top route in all animals. In each group, five animals were sacrificed immediately after surgery, and the remaining seven were sacrificed at 6 weeks postoperatively. Biomechanical and histologic evaluations were performed. In pull out testing, the ultimate failure load and the linear stiffness of the graft-tibia complex harvested at 6 weeks were significantly greater than those harvested at the time-zero period. There were no significant differences in those parameters between groups I and II at 6 weeks. In each group, the perpendicular collagen fibers connecting the tendon to the bone tunnel wall were observed only in the narrow area located close to the intra-articular tunnel outlet. In conclusion, excessively long placement of the flexor graft within the bone tunnel does not result in an additional increase of anchoring strength and stiffness of the graft in ACL reconstruction.

Animals↗

PubMed2006

Palliative spinal reconstruction using cervical pedicle screws for metastatic lesions of the spine: a retrospective analysis of 32 cases.

STUDY DESIGN: A retrospective study. OBJECTIVES: To evaluate clinical outcomes of palliative spinal reconstruction using cervical pedicle screws in metastatic spine tumors. SUMMARY OF BACKGROUND DATA: No study to date has investigated the effectiveness of cervical pedicle screw fixation in metastatic lesions of the spine. METHODS: A total of 32 patients with metastatic spine tumors who underwent reconstructive surgery using cervical pedicle screws were reviewed. Four patients presented upper cervical lesions and 28 patients had subaxial lesions. All patients had intractable pain, 29 presented myelopathy, and 18 patients were nonambulatory. Combined anterior column reconstruction was considered in cases of life expectancy more than 2 years and anterior spinal cord compression that could not be solved by posterior decompression and kyphosis correction. Posterior fixation alone was performed in 25 patients, and posterior fixation combined with anterior column reconstruction was performed in 7 patients. RESULTS: The average postoperative survival period was 12.2 months. Neck pain was improved in all cases. Twenty-four (83%) of the 29 patients with spinal cord lesions presented neurologic improvement. Of 18 patients who were not ambulatory, 16 patients (89%) became ambulatory. Pain relief, neurologic function, and spinal stability were maintained throughout the survival period in 30 of 32 patients (94%). CONCLUSION: Spinal reconstruction using cervical pedicle screws improved spinal stability, pain, and neurologic function. These improvements were maintained throughout the survival period in 94% of the patients. Anterior column reconstruction could be avoided in 78% of the patients in spite of damaged anterior column.

Adult↗

PubMed2006

Tight fit technique in primary hybrid total hip arthroplasty for patients with hip dysplasia.

This article presents the midterm results of hybrid total hip arthroplasty for patients with hip dysplasia by use of a tight fit technique for the femoral component. We followed up 113 hips in 99 patients for a mean of 11 years. All final femoral rasps used in this study overrasped by 0.5 to 1.0 mm for stem insertion, resulting in relatively thin cement mantles. Both components of one hip were removed because of infection. The other 5 acetabular components were revised for osteolysis, recurrent dislocation, or dislodgement of the polyethylene liner. No femoral component was revised for aseptic loosening. We conclude that the tight fit technique using a canal-filling stem may produce good long-term results for patients with hip dysplasia.

Adult↗

PubMed2006

Autologous osteochondral mosaicplasty for capitellar osteochondritis dissecans in teenaged patients.

BACKGROUND: Autologous osteochondral mosaicplasty is a new technique to provide hyaline repair for articular defects. Although recent studies have reported the successful treatment of articular defects in the knee and ankle joints with this surgical procedure, little attention has been given to the surgical efficacy of mosaicplasty in the treatment of osteochondritis dissecans of the humeral capitellum. PURPOSE: To clarify the clinical outcomes of mosaicplasty for teenaged patients with advanced lesions of capitellar osteochondritis dissecans. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Eight teenaged patients with advanced lesions of capitellar osteochondritis dissecans underwent mosaicplasties. All patients were baseball players who were affected on the right side, which was also their throwing side. The surgical technique involves obtaining small-sized cylindrical osteochondral grafts from the lateral periphery of the femoral condyles and transplanting them to prepared osteochondral defects. At a mean follow-up of 24 months, all patients were evaluated clinically and radiographically. RESULTS: Seven of the 8 patients were free from elbow pain, and the remaining patient had mild pain occasionally. The mean clinical score described by Timmerman and Andrews (a maximum of 200 points) significantly improved from 140 points to 183 points postoperatively. All patients except one had excellent or good clinical results. Radiographically, the graft incorporation and a normal contour of the subchondral cortex were found in all patients. Magnetic resonance imaging showed that the preoperative heterogeneity of the lesion had disappeared and the signal intensity returned to normal. Six of the 8 patients, including all 3 pitchers, returned to competitive-level baseball. CONCLUSION: Mosaicplasty for advanced lesions of capitellar osteochondritis dissecans in teenaged baseball players can provide satisfactory clinical and radiographic results.

Adolescent↗

PubMed2006

Multidirectional flexibility analysis of anterior and posterior lumbar artificial disc reconstruction: in vitro human cadaveric spine model.

The in vitro multidirectional flexibility analysis was conducted to investigate the initial biomechanical effect of biomimetic artificial intervertebral disc replacement from either anterior or posterior approach in a cadaveric lumbosacral spine model. Two designs of anterior total and posterior subtotal artificial discs were developed using bioactive three-dimensional fabric and bioresorbable hydroxyapatite/poly-l-lactide material (3DF disc). Both models were designed to obtain the stable interface bonding to vertebral endplates with maximum surface area occupation. Using seven cadaveric lumbosacral spines, the following three anterior reconstruction methods were sequentially performed at L4-5 level: anterior 3DF disc replacement; anterior BAK cages (BAK); and posterior pedicle screw fixation and anterior BAK cages combined (BAK + PS). The L2-3 level received two methods of posterior reconstructions: subtotal 3DF disc replacement (two implants), and posterior interbody cages and pedicle screw fixation (PLIF). Six unconstrained pure moments were applied and three-dimensional segmental motions were measured with an optoelectronic motion measurement system. The center of rotation (COR) calculation was conducted radiographically using flexion-extension films. Both anterior and posterior 3DF replacements statistically demonstrated equivalent range of motions (ROMs) in all loading modes compared to intact segment. Anterior BAK, BAK + PS, and PLIF demonstrated significantly lower ROMs when compared to intact and 3DF groups (P<0.05). The 3DF reconstruction tended to realign the COR to the posterior third or surrounding position at the operative disc level. The stand-alone lumbar 3DF disc replacement demonstrated biomechanical characteristics nearly equivalent to the intact spinal segments even through anterior or posterior approach in vitro, suggesting an excellent clinical potential.

Absorbable Implants↗

PubMed2006

Macrophage migration inhibitory factor-deficient mice are resistant to ovariectomy-induced bone loss.

A link between macrophage migration inhibitory factor (MIF) and estrogen has recently emerged. We examined the involvement of MIF in osteoporotic changes in bone after ovariectomy (OVX), and revealed that MIF-deficient mice (MIF-KO) were completely protected from this phenomenon. The increase in osteoclast number per bone surface and serum IL-1beta levels, which were observed in wild-type mice after OVX, did not occur in MIF KO. Our data suggest that MIF plays an important role in the pathogenesis of postmenopausal osteoporosis, and could be a novel target for the treatment of this disease.

Animals↗

PubMed2006

Cementless total hip arthroplasty using the modular S-ROM prosthesis combined with corrective proximal femoral osteotomy.

We present the results of total hip arthroplasty using S-ROM (Depuy, Warsaw, Ind) prosthesis combined with corrective femoral transverse osteotomy for hips with proximal femoral deformity. Fourteen hips were followed up for a mean of 61 months (range, 36-95 months), with a mean age at surgery of 55 years (range, 44-69 years). The average intraoperative blood loss was 638 mL, and the average operative time was 136 minutes. The average Harris Hip Score increased from 38.0 (range, 15.0-55.7) preoperatively to 82.0 (range, 34.6-92.7) at the latest follow-up. All the hips except for 1 acquired union of osteotomy and bone ingrowth. S-ROM modular stem, which gives sufficient rotational stability at both proximal and distal parts of the osteotomy, is useful for total hip arthroplasty combined with corrective femoral transverse osteotomy.

Adult↗

PubMed2006

Stabilization of the proximal ulnar stump in the Sauvé-Kapandji procedure by using the extensor carpi ulnaris tendon: long-term follow-up studies.

PURPOSE: The Sauvé-Kapandji procedure is considered a useful treatment option for distal radioulnar disorders. Postoperative instability of the proximal ulnar stump and radioulnar convergence, however, may be symptomatic. We modified the Sauvé-Kapandji procedure by stabilizing the proximal ulnar stump with a half-slip of the extensor carpi ulnaris tendon. We previously reported on 13 patients with this procedure at an average follow-up period of 35 months; the patients had satisfactory clinical results and improved stability of the proximal ulnar stump as shown by x-ray examination. In this article we address the question of whether those clinical and radiographic results noted at an average follow-up period of 35 months after surgery were maintained at later follow-up examinations. METHODS: We re-examined 12 of the 13 original patients and compared their initial follow-up results with their current results after an average follow-up period of 95 months. RESULTS: The results of this series after 95 months of follow-up evaluation were similar to the results at 35 months. CONCLUSIONS: The results presented in this article suggest that the clinical radiographic results at the 35-month follow-up examination were maintained in the long-term 95-month follow-up evaluation despite the finding that the hole in the proximal ulnar stump had broken in 3 wrists at follow-up examination. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.

Adult↗

PubMed2006

Specific cell behavior of human fibroblast onto carbohydrate surface detected by glycoblotting films.

We synthesized an aminooxyl polymer that is reactive with the reduced end of carbohydrates using our sugar-displaying approach. The carbohydrates were easily immobilized on the polymer film (glycoblotting film) by simple immersion in a in sugar solution through stable oxime bond. The in vitro behaviors of human fibroblasts on the carbohydrate-coated surface were investigated. The adhesion of human fibroblasts on the cellobiose- and cellotriose-coated surfaces was much greater than on the other coated surfaces and the noncoated surface. This result indicated that simple structural differences in carbohydrates induced biological changes in human cells, especially cell adhesion. Our approach provides a high-throughput assay system for carbohydrate-related cell adhesion and proliferation.

Carbohydrates↗

PubMed2006

Fixation with poly-L-lactide screws in hip osteotomies.

UNLABELLED: The purpose of our study was to investigate the bone union rates and complication rates, including breakage of screws, infection, and osteolysis, in hip osteotomies using poly-L-lactic screws. We prospectively followed up 111 hips in 100 patients using conventional radiography, in which 81 rotational acetabular osteotomies, 26 Chiari pelvic osteotomies, and four Sugioka's transtrochanteric osteotomies were performed. The mean age of the patients at the time of surgery was 34 years, and the mean followup was 5.4 years. Eighty-one osteotomized acetabula and 98 osteotomized greater trochanters were fixed using poly-L-lactic screws. These hips were compared with 64 hips in 58 patients using metallic screws. Bone union was achieved in 80 of the 81 acetabular osteotomies, except in one hip with postoperative deep infection. Proximal displacement of the greater trochanter because of poly-L-lactic screw breakage occurred in six (6%) hips. None of the metallic screws broke. Osteolysis occurred in one hip with a trochanteric osteotomy using poly-L-lactic screws. Poly-L-lactic screws are suitable to transfix the osteotomized acetabulum, but there is some risk of fracture when used to reattach an osteotomized greater trochanter. Complete bone ingrowth in the screw channels cannot be expected for several years after insertion. Osteolysis is a possible complication. LEVEL OF EVIDENCE: Therapeutic study, Level II (prospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.

Absorbable Implants↗

PubMed2006

Adaptor molecule Crk is required for sustained phosphorylation of Grb2-associated binder 1 and hepatocyte growth factor-induced cell motility of human synovial sarcoma cell lines.

Activation of the c-Met receptor tyrosine kinase through its ligand, hepatocyte growth factor (HGF), promotes mitogenic, motogenic, and morphogenic cellular responses. Aberrant HGF/c-Met signaling has been strongly implicated in tumor cell invasion and metastasis. Both HGF and its receptor c-Met have been shown to be overexpressed in human synovial sarcoma, which often metastasizes to the lung; however, little is known about HGF-mediated biological effects in this sarcoma. Here, we provide evidence that Crk adaptor protein is required for the sustained phosphorylation of c-Met-docking protein Grb2-associated binder 1 (Gab1) in response to HGF, leading to the enhanced cell motility of human synovial sarcoma cell lines SYO-1, HS-SY-II, and Fuji. HGF stimulation induced the sustained phosphorylation on Y307 of Gab1 where Crk was recruited. Crk knockdown by RNA interference disturbed this HGF-induced tyrosine phosphorylation of Gab1. By mutational analysis, we identified that Src homology 2 domain of Crk is indispensable for the induction of the phosphorylation on multiple Tyr-X-X-Pro motifs containing Y307 in Gab1. HGF remarkably stimulated cell motility and scattering of synovial sarcoma cell lines, consistent with the prominent activation of Rac1, extreme filopodia formation, and membrane ruffling. Importantly, the elimination of Crk in these cells induced the disorganization of actin cytoskeleton and complete abolishment of HGF-mediated Rac1 activation and cell motility. Time-lapse microscopic analysis revealed the significant attenuation in scattering of Crk knockdown cells following HGF treatment. Furthermore, the depletion of Crk remarkably inhibited the tumor formation and its invasive growth in vivo. These results suggest that the sustained phosphorylation of Gab1 through Crk in response to HGF contributes to the prominent activation of Rac1 leading to enhanced cell motility, scattering, and cell invasion, which may support the crucial role of Crk in the aggressiveness of human synovial sarcoma.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Relationship between bone marrow edema and development of symptoms in patients with osteonecrosis of the femoral head.

OBJECTIVE: The purpose of this study was to determine the significance of risk factors on MR images for predicting the outcome of patients with osteonecrosis of the femoral head. SUBJECTS AND METHODS: Eighty-three asymptomatic or minimally symptomatic hips in 61 consecutive patients were followed up prospectively. Inclusion criteria included osteonecrosis of the femoral head identified by typical MRI findings, with no radiographic evidence of progression of collapse, and Harris hip score of 85 points or more. Every 3 months, the patients underwent clinical and radiographic examination, and MR images were obtained at 6- to 12-month intervals. Follow-up continued until worsening of hip pain with Harris hip score of less than 70 points or surgery. Asymptomatic hips were followed up for at least 24 months. The mean clinical and radiographic follow-up period after the initial diagnosis was 60 months (range, 3-168 months). RESULTS: Thirty-six (43%) of the 83 hips were symptomatic at the last follow-up. Bone marrow edema was present in 28 hips (34%) during the follow-up period. Twenty-seven (96%) of the 28 hips were symptomatic, and bone marrow edema significantly correlated with worsening of hip pain (p < 0.0001). The necrotic volume of hips with bone marrow edema was significantly larger than those without bone marrow edema (p < 0.0001). Bone marrow edema was found to be the most significant risk factor for worsening of pain (p < 0.0001). CONCLUSION: Bone marrow edema strongly correlated with necrotic volume and was the most significant risk factor for worsening of hip pain. A large necrotic volume of 30% or more may be the second useful indicator for predicting future worsening of hip pain.

Adolescent↗