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Biomedical subjects

Akio Minami

Publications and source records attributed to Akio Minami.

At least 73 records · Page 4Linked to original sources
PubMed2004

Macrophage migration inhibitory factor up-regulates the expression of interleukin-8 messenger RNA in synovial fibroblasts of rheumatoid arthritis patients: common transcriptional regulatory mechanism between interleukin-8 and interleukin-1beta.

OBJECTIVE: Interleukin-8 (IL-8) plays an important role in the migration of inflammatory cells into the synovium and joint fluids in rheumatoid arthritis (RA). This study was undertaken to investigate the IL-8 inductive activity of the macrophage migration inhibitory factor (MIF) in RA synovial fibroblasts. The regulatory mechanism of IL-8 was compared with that of IL-1beta. METHODS: MIF-induced IL-8 and IL-1beta transcriptional activation was studied in RA synovial fibroblasts by Northern blot analysis, enzyme-linked immunosorbent assay, and electromobility shift assay. The effect of anti-MIF antibody administration on murine passive collagen-induced arthritis (CIA) was also evaluated by histologic examination and reverse transcriptase-polymerase chain reaction. RESULTS: MIF up-regulated the IL-8 messenger RNA (mRNA) and protein levels in a dose-dependent manner. The IL-8 mRNA up-regulation started 1 hour poststimulation by MIF, and reached a maximum level at 6 hours. IL-1beta mRNA was also up-regulated by MIF. The mRNA up-regulation of IL-8 and IL-1beta by MIF was inhibited by 2 tyrosine kinase inhibitors, a protein kinase C (PKC) inhibitor, an activator protein 1 (AP-1) inhibitor, and by an NF-kappaB inhibitor. A cAMP-dependent kinase inhibitor did not inhibit it. MIF enhanced AP-1 and NF-kappaB binding activities in a dose-dependent manner. Passive CIA enhanced mRNA levels of macrophage inflammatory protein 2 and cytokine-induced neutrophil chemoattractants and, moreover, migration and proliferation of inflammatory cells within the synovium, which were suppressed by administration of an anti-MIF antibody. CONCLUSION: MIF may play an important role in the migration of inflammatory cells into the synovium of rheumatoid joints via induction of IL-8. MIF up-regulates IL-8 and IL-1beta mRNA via tyrosine kinase-, PKC-, AP-1-, and NF-kappaB-dependent pathways.

Arthritis, Rheumatoid↗
PubMed2004

Quantitative evaluation of long sitting in paraplegic patients with spinal cord injury.

OBJECTIVES: To evaluate the characteristics of long sitting (ie, sitting with legs extended) in patients with spinal cord injury (SCI) and to compare these results with able-bodied control subjects. DESIGN: A kinematic study using a video camera and forceplate with a strain-gauge type load cell. SETTING: A referral center for patients with SCI in Japan. PARTICIPANTS: Twenty-four subjects, including 11 able-bodied, matched control subjects and 13 SCI patients with complete paraplegia. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Sitting posture in the sagittal plane as well as the movement pattern and distance of the center of pressure (COP). RESULTS: Patients with SCI kept their pelvis tilted posteriorly and the lumbar spine was less lordotic during long sitting. The changing COP pattern during long sitting differed in able-bodied subjects as compared patients with SCI. During long sitting with arms outstretched over the thighs, COP movement in the subjects with SCI was significantly greater than that in the able-bodied subjects. When the arms were outstretched over the thighs, the COP shifted anteriorly in the able-bodied subjects and posteriorly in the patients with SCI. CONCLUSIONS: Long sitting in the paraplegic patients with SCI was unstable compared with the able-bodied subjects. The COP distribution pattern differed significantly between the 2 groups. The support and function of the upper extremities may influence balance during long sitting in the patients with SCI. The method of seating evaluation using a video camera and gravicorder was easy to use and appeared to provide an objective measurement of dynamic seating function in the patients with SCI.

Activities of Daily Living↗
PubMed2004

Anatomic reconstruction of the anteromedial and posterolateral bundles of the anterior cruciate ligament using hamstring tendon grafts.

PURPOSE: To develop and evaluate an anatomic reconstruction procedure of the posterolateral and anteromedial bundles of the anterior cruciate ligament (ACL). TYPE OF STUDY: Anatomic study and case series. METHODS: The femoral attachment of the anteromedial and posterolateral bundles of the ACL was anatomically analyzed with 5 cadaveric knees. Using another 3 cadaveric knees, anatomic reconstruction of the posterolateral and anteromedial bundles was performed with the transtibial technique, and tunnel positioning and graft function in a range of knee motion was observed. Based on this anatomic study, an anatomic reconstruction procedure of the anteromedial and posterolateral bundles was developed using hamstring tendon autografts. This procedure was carried out in 57 consecutive patients with an ACL-deficient knee. The patients were followed-up for a minimum of 24 months. RESULTS: We developed the arthroscopically assisted anatomic reconstruction procedure of the posterolateral and anteromedial bundles, involving a new method of creating the tibial and femoral tunnels for the posterolateral bundle. To visualize the femoral attachment of the posterolateral bundle, the medial infrapatellar portal was more useful than the lateral portal. In clinical results, the side-to-side difference of anterior laxity averaged 1.0 mm with a standard deviation of 0.9. CONCLUSIONS: The anatomic reconstruction of the anteromedial and posterolateral bundles using hamstring tendon autografts is clinically practical in the treatment for the ACL-deficient knee. LEVEL OF EVIDENCE: Level IV.

Adult↗
PubMed2004

Reduction of initial tension in the in situ frozen anterior cruciate ligament.

The purposes of this study were to develop a new method to measure in situ tension in the anterior cruciate ligament, and to show degradation changes in the tension applied to the in situ frozen-thawed anterior cruciate ligament during a 12-week period postoperatively. Eighteen mature Beagles were used in the current study. Each dog had the in situ freeze and thaw treatment to its anterior cruciate ligament, and an initial tension of 20 N was applied to the anterior cruciate ligament. The in situ tension in the anterior cruciate ligament was measured immediately after surgery (n = 4) and at 6 and 12 weeks (n = 5, respectively) with a method developed specifically for this study. A commercially available force transducer, the utility and the validity of which were established in previous studies, was inserted into the anterior cruciate ligament, and the transducer was calibrated in situ using a tensile tester after sacrifice. The four remaining animals were used for histologic examinations. The average tension in the anterior cruciate ligament decreased from 19.1 N immediately after surgery to 14.2 N and 4.7 N at 6 and 12 weeks, respectively. There were significant differences among the times. At 12 weeks, histologically, degenerative changes were seen with asteroid-shaped cells and vacuoles in the anterior cruciate ligament. The current study showed that the high initial tension applied to the in situ frozen anterior cruciate ligament gradually decreased with time until 12 weeks.

Analysis of Variance↗
PubMed2004

Magnetic resonance imaging in stress fractures and shin splints.

The purpose of the current study was to determine whether stress fractures and shin splints could be discriminated with MRI in the early phase. Twenty-two athletes, who had pain in the middle or distal part of their leg during or after sports activity, were evaluated with radiographs and MRI scans. Stress fractures were diagnosed when consecutive radiographs showed local periosteal reaction or a fracture line, and shin splints were diagnosed in all the other cases. In all eight patients with stress fractures, an abnormally wide high signal in the localized bone marrow was the most detectable in the coronal fat-suppressed MRI scan. In 11 patients with shin splints, the coronal fat-suppressed MRI scans showed a linear abnormally high signal along the medial posterior surface of the tibia, and in seven patients with shin splints, the MRI scans showed a linear abnormally high signal along the medial bone marrow. No MRI scans of shin splints showed an abnormally wide high signal in the bone marrow as observed on MRI scans of stress fractures. This study showed that fat-suppressed MRI is useful for discrimination between stress fracture and shin splints before radiographs show a detectable periosteal reaction in the tibia.

Adolescent↗
PubMed2004

The effect of growth factors on biomechanical properties of the bone-patellar tendon-bone graft after anterior cruciate ligament reconstruction: a canine model study.

BACKGROUND: No studies have dealt with the effect of growth factors on the free tendon autograft in anterior cruciate ligament reconstruction. HYPOTHESIS: Application of exogenous transforming growth factor-beta and epidermal growth factor may affect the structural properties and histology of the bone-patellar tendon-bone autograft after anterior cruciate ligament reconstruction. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty dogs underwent anterior cruciate ligament reconstruction with the autogenous bone-patellar tendon-bone graft in bilateral knees. In 10 animals, 12 ng transforming growth factor-beta and 300 ng epidermal growth factor mixed with fibrin sealant of 0.6 mL were applied to the left knee. In the remaining 10 dogs, fibrin sealant alone was applied to the left knee. No additional treatments were applied to the right knee. RESULTS: The growth factor application increased the stiffness and maximum failure load of the femur-graft-tibia complex at 12 weeks (P =.016 and P =.012, respectively); the sham treatment did not significantly affect them. Histologically, most of the cells in the grafts treated with growth factors had spindle-shaped nuclei; cells in the other grafts had round-shaped nuclei. CONCLUSIONS: Application of transforming growth factor-beta and epidermal growth factor improves the structural properties of the autograft after anterior cruciate ligament reconstruction in the canine model. CLINICAL RELEVANCE: Application of growth factors is a possible strategy to prevent graft deterioration in anterior cruciate ligament reconstruction.

Animals↗
PubMed2004

Chiari pelvic osteotomy for advanced osteoarthritis in patients with hip dysplasia.

BACKGROUND: It is not clear whether a Chiari pelvic osteotomy performed for the treatment of advanced osteoarthritis can delay the need for total hip arthroplasty. We present the mid-term results of the Chiari pelvic osteotomy performed for the treatment of Tönnis grade-3 osteoarthritis (large cysts, severe narrowing of the joint space, or severe deformity or necrosis of the head with extensive osteophyte formation), with a particular focus on whether this procedure can delay the need for total hip arthroplasty. METHODS: We followed thirty-two hips in thirty-one patients with Tönnis grade-3 osteoarthritis who had refused total hip arthroplasty and had been treated with a Chiari pelvic osteotomy. The mean age at the time of surgery was 35.2 years. The mean duration of follow-up was 11.2 years, at which time clinical evaluation with the Harris hip score and radiographic evaluation were performed. RESULTS: The average Harris hip score improved from 52 points preoperatively to 77 points at the time of follow-up; the average pain score improved from 20 to 31 points. Three hips with a hip score of <70 points required total hip arthroplasty. With a hip score of <70 points as the end point, the cumulative rate of survival at ten years was 72%. The clinical outcome was significantly influenced by the preoperative center-edge angle (p = 0.004), the preoperative acetabular head index (p = 0.039), achievement of the appropriate osteotomy level (p = 0.011), and superior migration (p = 0.009) and lateral migration (p = 0.026) of the femoral head. CONCLUSIONS: Although the clinical results were inferior to those of total hip arthroplasty, Chiari pelvic osteotomy may be an option for young patients with advanced osteoarthritis who prefer a joint-conserving procedure to total hip arthroplasty and accept a clinical outcome that is predicted to be less optimal than that of total hip arthroplasty. Moderate dysplasia and moderate subluxation without complete obliteration of the joint space and a preoperative center-edge angle of at least -10 degrees are desirable selection criteria.

Adolescent↗
PubMed2004

Two-year observation of artificial intervertebral disc replacement: results after supplemental ultra-high strength bioresorbable spinal stabilization.

OBJECT: This 2-year experimental study was conducted to investigate the efficacy of a bioactive three-dimensional (3D) fabric disc for lumbar intervertebral disc replacement. The authors used a bioresorbable spinal fixation rod consisting of a forged composite of particulate unsintered hydroxyapatite/poly-L-lactide acid (HA/PLLA) for stability augmentation. The biomechanical and histological alterations as well as possible device-related loosening were examined at 2 years postoperatively. METHODS: Two lumbar intervertebral discs (L2-3 and L4-5) were replaced with the 3D fabric discs, which were augmented by two titanium screws and a spanning bioresorbable rod (HA/PLLA). The segmental biomechanics and interface bone ingrowth were investigated at 6, 15, and 24 months postoperatively, and results were compared with the other two surgical groups (3D fabric disc alone; 3D fabric disc with additional anterior instrumentation stabilization). The 3D fabric disc and HA/PLLA-spinal segments demonstrated segmental mobility at 15 and 24 months; however, the range of motion (ROM) in flexion-extension decreased to 49 and 40%, respectively, despite statistically equivalent preserved torsional ROM. Histologically there was excellent osseous fusion at the 3D fabric disc surface-vertebral body interface. At 2 years posttreatment, no adverse tissue reaction nor aseptic loosening of the device was observed. CONCLUSIONS: Intervertebral disc replacement with the 3D fabric disc was viable and when used in conjunction with the bioresorbable HA/PLLA spinal augmentation. Further refinements of device design to create a stand-alone type are necessary to obviate the need for additional spinal stabilization.

Animals↗
PubMed2003

Migration of intracranial hemostatic clip into the lumbar spinal canal causing sacral radiculopathy: a case report.

STUDY DESIGN: A case report. OBJECTIVES: A case of spontaneous migration of intracranial hemostatic clip into the lumbar spinal canal causing a sacral radiculopathy and severe low back pain was presented. SUMMARY OF BACKGROUND DATA: Only five cases have been reported in the literature. The first report was described by Oyesiku in 1986; thereafter, four cases have been reported. This serves as the first report clearly describing the relationship between the migrated site of a foreign body and neurologic symptom, as well as achieving a remission of symptom after surgical extirpation. METHODS: A patient who had received hemostatic clips to the aqueductal stenosis 31 years ago presented with low back pain and sacral radiculopathy. Plain radiography, myelography, and subsequent CT revealed that a metal foreign body was located in the subarachnoid space at L4 level. Laminectomy of L4 and extirpation of the foreign body were performed. RESULTS: The foreign body was a hemostatic clip made of cobalt-based alloy that had been applied during the previous intracranial surgery. The clip irritated the adjoined intrathecal nerve root and possibly caused the adhesive arachnoiditis. All symptoms completely disappeared after the extirpation. CONCLUSIONS: An uncommon case of an intracranial hemostatic clip migrating into the lumbar subarachnoid space as well as causing sacral radiculopathy was reported. The surgical extirpation provided an excellent clinical outcome.

Foreign-Body Migration↗
PubMed2003

Static and dynamic analysis of five anterior instrumentation systems for thoracolumbar scoliosis.

STUDY DESIGN: A nondestructive biomechanical investigation among five anterior spinal instrumentation systems for scoliosis. OBJECTIVES: The purpose of this study is to analyze the static and dynamic biomechanical stability of five different systems. SUMMARY OF BACKGROUND DATA: Although a variety of anterior spinal instrumentation systems for scoliosis are available, very few attempts have been made at comparative biomechanical studies. METHODS: Thirty calf spines were underwent static biomechanical tests, including flexion-extension, axial rotation, and lateral bending loading modes in the multisegmental spinal model. Five anterior instrumentation systems included: 1) Texas Scottish Rite Hospital system; 2) Bad Wildungen Metz; 3) anterior ISOLA; 4) Cotrel-Dubousset Hoph; and 5) Kaneda Anterior Scoliosis System. The initial and postfatigue stability after a cyclic loading test were analyzed by measuring the range of motion at instrumented segments compared to the intact within the same specimen (% to intact). RESULTS: Two-rod systems showed a significant decrease in range of motion compared to one-rod systems in flexion-extension (P < 0.001) and axial rotation (P < 0.05). In lateral bending, all systems demonstrated a significant decrease in range of motion of less than 40% to the intact (P < 0.001). After cyclical loading test, all systems increased in range of motion. In flexion-extension, one-rod systems depicted a significant increase in range of motion, compared to two-rod systems (P < 0.05). CONCLUSIONS: In the initial stability analysis, two-rod systems are superior to one-rod systems. For one-rod systems, repeated physiologic loading may result in reduced stability in flexion-extension.

Analysis of Variance↗
PubMed2003

Types of spinal instability that require interbody support in posterior lumbar reconstruction: an in vitro biomechanical investigation.

STUDY DESIGN: Pedicle screw fixation alone for sequential spinal instabilities was biomechanically compared with pedicle screw fixation using interbody cages. OBJECTIVE: To evaluate biomechanical effects of interbody cages on construct stiffness, pedicle-screw strain, and the adjacent level in posterior lumbar reconstruction using pedicle screw fixation. SUMMARY OF BACKGROUND DATA: It remains undetermined what types of spinal instability require interbody support in posterior lumbar reconstruction. METHODS: For this study, 10 calf spines (L3-L6) were used. Sequential destabilization was performed at L4-L5 followed by posterior reconstruction using pedicle screw fixation (PS) and interbody cages as follows: intact + PS (I-PS), medial facetectomy + PS (MF-PS), total facetectomy + PS (TF-PS), partial discectomy + PS (D-PS), and D-PS + interbody cages (PLIF). Biomechanical testing was performed under flexion and extension loading modes. Construct stiffness (L4-L5), rod-screw bending strain, and range of motion (ROM) at the upper adjacent level (L3-L4) were analyzed. RESULTS: In terms of construct stiffness (L4-L5), all the reconstructions except D-PS demonstrated higher construct stiffness than the intact spine (P < 0.05). The PLIF showed the highest stiffness among all the reconstructions (P < 0.05). In terms of ROM (L3-L4), all the reconstructions increased the ROM, as compared with the intact state (P < 0.05). Importantly, PLIF showed significantly greater ROM than all the other reconstructions except I-PS (P < 0.05). In terms of rod-screw strain, the D-PS resulted in higher strain than the other groups (P < 0.05). The PLIF presented less strain than the other reconstructions (P < 0.05). CONCLUSIONS: For spinal instability with preserved anterior load sharing, pedicle screw fixation alone is biomechanically adequate, and interbody cages should not be used because they further increase segmental motion at the adjacent segment. However, PS alone provides insufficient stability and high implant strain in case of damaged anterior column. In such cases, additional interbody cages significantly increase construct stiffness and decrease hardware strain. However, they increase ROM at the adjacent segment as well.

Animals↗
PubMed2003

Effect of single-dose administration of FK-506 on allogeneic limb transplantation in rats: is there an optimal timing of its administration?

Although a number of experimental studies have demonstrated that high-dose administration of FK-506 induces the success of limb allogeneic transplantation in rats, some of them have reported occurrences of lethal side effects. Therefore, a more effective regimen with lower-dose administration of this agent must be developed. The objective of this study was to determine an optimal timing of a single-dose administration of FK-506 in rat limb allografts. In the current study, orthotopic hindlimb transplantations were performed using major histocompatibility mismatched pairs of inbred rats. The rats were classified into five groups on the basis of the different time schedules of FK-506 administration as follows: syngeneic group, Lewis-to-Lewis transplantation; control group, ACI-to-Lewis without any immunotherapy; day 0 group, recipients treated with a single-dose administration of FK-506 (5 mg/kg of body weight, intramuscular injection) at day 0 postoperatively; day 1 group, with a single-dose administration of FK-506 at day 1 postoperatively; and day 2 group, with a single-dose administration of FK-506 at day 2 postoperatively. The median graft survival time in each group (n = 5) was 9 days in the control group, 19 days in the day 0 group, 49 days in the day 1 group, and 42 days in the day 2 group. The values in the day 1 and the day 2 groups significantly increased compared with those in other groups. For prolonged survival of a grafted limb, a single-dose administration of FK-506 is more effective at 24 to 48 hours after transplantation.

Animals↗
PubMed2003

Bone ingrowth fixation of artificial intervertebral disc consisting of bioceramic-coated three-dimensional fabric.

STUDY DESIGN: The bone-bonding characteristic of the new artificial intervertebral disc consisting of bioceramic-coated three-dimensional fabric was evaluated mechanically and histologically in an in vivo sheep model. OBJECTIVES: To investigate the mechanical properties and the histologic appearance of the interface between the three-dimensional fabric disc and the vertebral body, and to evaluate these alterations in vivo under a spinal segmentally mobile condition. SUMMARY OF BACKGROUND DATA: Bone ingrowth to the bioceramic-coated three-dimensional fabric surface had been demonstrated already under a stable environment in preliminary animal studies. METHODS: For this study, 20 sheep underwent two-level lumbar intervertebral disc replacement with three-dimensional fabric discs (Group I) or bioceramic spacers as a comparative material (Group II). All operative segments were stabilized temporarily with spinal instrumentation for the initial ingrown phase. Four animals each were killed at 4, 6, 15, and 24 months in Group I and at 6 months in Group II, and the operative segments were subjected to either a detachment test or histologic evaluation. RESULTS: The interfacial tensile strength at 6 months was significantly higher in Group I than in Group II. No significant decrease in tensile strength was detected until 24 months after surgery in Group I. Histologically, bone ingrowth to the three-dimensional fabric surface was observed 4 months after surgery, and no aseptic loosening occurred until 24 months after surgery. CONCLUSIONS: The findings show that the three-dimensional fabric disc was firmly fixed to the vertebral body by bone ingrowth, and that this biologic fixation was preserved even under the spinal segmentally mobile condition.

Animals↗
PubMed2003

Stress shielding of patellar tendon: effect on small-diameter collagen fibrils in a rabbit model.

The purpose of this study was to assess the effects of stress shielding on the microstructure and ultrastructure of the patellar tendon using 40 mature female Japanese white rabbits. The patellar tendon was completely released from stress by drawing the patella toward the tibial tubercle with a stainless steel wire installed between them. Microstructurally, stress shielding for 3 and 6 weeks increased the number of cells approximately fivefold, to that of the control tendon. Collagen bundles were less well oriented in the stress-shielded tendon than in the control. Ultrastructurally, small collagen fibrils with a diameter of less than 90 nm increased in the stress-shielded tendon. The median collagen fibril diameter in 6-week stress-shielded tendon was significantly smaller ( P << 0.05) than in the control tendon (58.8% of control). The ratio of the total area of collagen fibrils to the whole visualized area in the stress-shielded patellar tendon was significantly smaller at 3 and 6 weeks than that in the control. This study demonstrated that complete stress shielding significantly affects the microstructure and ultrastructure of the patellar tendon

Analysis of Variance↗
PubMed2003

Juvenile Blount's disease: bilateral case with asynchronous onset.

We encountered a rare case of bilateral juvenile Blount's disease diagnosed as unilateral at the onset. The patient was a 9-year-old girl who visited our outpatient clinic with pain and deformity in the left knee. Examination of the left knee showed severe varus deformity. Correction of the varus deformity and tibial shortness was carried out at the same time by the callotasis method using an Orthofix external fixator. During follow-up the varus deformity in her right knee gradually progressed. At 18 months after the initial surgery, the right varus deformity and tibial shortness were corrected at the same time by the callotasis method using an Orthofix external fixator; proximal epiphysiodesis was also performed. The coronal-plane alignment of both knees remains good. In cases with bilateral involvement of Blount's disease, the onset of the deformity is usually nearly synchronous. In some cases, however, it begins unilaterally, as with this patient, so it is essential to check both sides by means of tomography or magnetic resonance imaging and not just radiography. Moreover, we must be careful to plan the treatment in such a case so as to anticipate possible leg-length discrepancy problems.

Bone Diseases, Developmental↗
PubMed2003

Scaphotrapeziotrapezoid fusion: long-term follow-up study.

The long-term effectiveness of scaphotrapeziotrapezoid (STT) fusion is still controversial. We evaluated our clinical and radiological results of 30 STT fusions in 30 patients (average age 41 years; 23 males, 7 females). The follow-up period averaged 84 months. The indications were Kienböck's disease ( n= 23), isolated STT arthrosis ( n = 6), and dislocation of the trapezium ( n = 1). A total of 26 simultaneous associated procedures were performed. Excisional arthroplasty of the lunate was done in all 23 patients with Kienböck's disease. Of the 30 total patients, 5 had postoperative pain ranging from mild to severe; 4 patients were dissatisfied with the results. Postoperative ranges of motion of the wrist were 84% of extension and 91% of flexion compared with preoperative motion. The postoperative grip strength improved to 27 kgf from the preoperative value of 18 kgf. Altogether, 26 patients returned to their previous activities. All patients obtained uneventful STT fusion in an average of 11.2 weeks. Eight patients (27%) experienced postoperative complications; seven had radioscaphoid arthroses, five had trapeziometacarpal arthrodeses, and one had a flexor pollicis longus tendon rupture. Although radioscaphoid arthrosis occurred in 23% of this series after STT fusion, the results suggest that it is an effective procedure for Kienböck's disease and isolated STT arthrosis.

Adolescent↗