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Natsuo Yasui

Publications and source records attributed to Natsuo Yasui.

At least 37 records · Page 2Linked to original sources
PubMed2005

Overexpression of HMGA2-LPP fusion transcripts promotes expression of the alpha 2 type XI collagen gene.

In a subset of human lipomas, a specific t(3;12) chromosome translocation gives rise to HMGA2-LPP fusion protein, containing the amino (N)-terminal DNA binding domains of HMGA2 fused to the carboxyl (C)-terminal LIM domains of LPP. In addition to its role in adipogenesis, several observations suggest that HMGA2-LPP is linked to chondrogenesis. Here, we analyzed whether HMGA2-LPP promotes chondrogenic differentiation, a marker of which is transactivation of the alpha 2 type XI collagen gene (Col11a2). Real-time PCR analysis showed that HMGA2-LPP and COL11A2 were co-expressed. Luciferase assay demonstrated that either of HMGA2-LPP, wild-type HMGA2 or the N-terminal HMGA2 transactivated the Col11a2 promoter in HeLa cells, while the C-terminal LPP did not. RT-PCR analysis revealed that HMGA2-LPP transcripts in lipomas with the fusion were 591-fold of full-length HMGA2 transcripts in lipomas without the fusion. These results indicate that in vivo overexpression of HMGA2-LPP promotes chondrogenesis by upregulating cartilage-specific collagen gene expression through the N-terminal DNA binding domains.

Binding Sites↗
PubMed2005

The alpha 2 type IX collagen gene tryptophan polymorphism is not associated with rheumatoid arthritis in the Japanese population.

The aim of this study was to investigate whether the alpha 2 type IX collagen (COL9A2) polymorphism that introduces tryptophan residue into the collagen triple-helix is a marker of susceptibility to, or severity of, rheumatoid arthritis (RA). The study included 749 Japanese patients with RA. One hundred twenty-four unrelated healthy individuals served as the control subjects. The relationship between the COL9A2 gene polymorphism and clinical manifestations of RA was evaluated. For the number of subjects positive for COL9A2 tryptophan polymorphism, there was no statistically significant difference between RA patients and normal controls. Furthermore, we did not detect any association of COL9A2 tryptophan polymorphism with disease status, least erosive subset, more erosive subset, or mutilating disease. The lack of association of COL9A2 tryptophan polymorphism with RA and the clinical findings in our study implies that the polymorphism may not function as a candidate gene marker for screening RA patients.

Adolescent↗
PubMed2005

Athletes with unilateral spondylolysis are at risk of stress fracture at the contralateral pedicle and pars interarticularis: a clinical and biomechanical study.

BACKGROUND: Unilateral spondylolysis is common in youths; its clinical and biomechanical features, especially effects on the contralateral side, are not fully understood. HYPOTHESIS: Unilateral spondylolysis predisposes the contralateral side to stress fracture, especially in athletes actively engaged in sporting activities involving torsion of the trunk. STUDY DESIGN: Case series and descriptive laboratory study. METHODS: Thirteen athletes younger than age 20 with unilateral spondylolysis were included. The contralateral pedicle and pars of spondylolytic vertebrae were examined using computed tomography and magnetic resonance imaging. Using a finite element model of the intact ligamentous L3-S1 segment, stress distributions were analyzed in response to 400-N axial compression and 10.6-N.m moment in flexion, extension, lateral bending, and axial rotation. Unilateral spondylolysis was created in the model at L5. The stress results from the unilateral defect model were compared to the intact model predictions and correlated to the contralateral defects seen in patients. RESULTS: Among 13 patients, there were 6 early-, 2 progressive-, and 5 terminal-stage defects. Three (23.1%) showed contralateral stress fracture. Among them, 2 belonged to the progressive-stage and 1 to the terminal-stage spondylolysis group. The remaining 4 patients in the terminal defect group showed stress reactions, such as sclerosis at the contralateral pedicle. In the finite element analysis model with an L5 left spondylolysis, the stresses at the contralateral and pars interarticularis were found to increase in all loading modes, with increases as high as 12.6-fold compared to the intact spine. CONCLUSIONS: Unilateral spondylolysis could lead to stress fracture or sclerosis at the contralateral side due to an increase in stresses in the region. CLINICAL RELEVANCE: Surgeons should be aware of possibility of contralateral stress fractures in cases in which patients, especially athletes engaged in active sports, show unilateral spondylolysis and persistent low back pain complaints.

Adolescent↗
PubMed2005

Association between single-nucleotide polymorphisms in the SEC8L1 gene, which encodes a subunit of the exocyst complex, and rheumatoid arthritis in a Japanese population.

OBJECTIVE: To identify rheumatoid arthritis (RA) susceptibility genes in a Japanese population by conducting a large-scale case-control association analysis and linkage disequilibrium (LD) mapping on chromosome 7q31-34, a candidate susceptibility locus identified in a preliminary genome-wide scan in 53 Japanese families, using single-nucleotide polymorphisms (SNPs). METHODS: We prepared 728 dense, evenly spaced SNPs with a minor allele frequency >0.15 in each gene locus on chromosome 7q31-34. Using these SNPs, a 2-stage case-control analysis was performed on 760 RA patients (157 men and 603 women) and 806 non-RA controls (189 men and 617 women). Haplotypes and LD mapping results were assessed based on SNP genotypes in 380 controls. RESULTS: Forty-eight SNPs showed allele associations (P < 0.05) in the first set of DNA samples (380 RA cases and 380 non-RA controls; first-stage analysis). For 4 of the SNPs in the SEC8L1 gene, the association was replicated (P < 0.05) in the second, independent set of DNA samples (an additional 380 RA cases and 380 non-RA controls; second-stage analysis). When data from the 2 groups were combined, the most significant allele association was observed with SNP 441, an intronic SNP of the SEC8L1 gene (P = 0.000059). The SEC8L1 SNPs with significant allele associations were all located in a single conserved LD block (block 4). Haplotype analysis revealed the disease-risk (P = 0.0015) and disease-protective (P = 0.0000062) haplotypes. Resequencing of coding exons within block 4 did not identify any nonsynonymous SNPs. Real-time quantitative polymerase chain reaction revealed that SEC8L1 was expressed ubiquitously in human tissues, including fibroblast-like synoviocytes from RA patients. CONCLUSION: Our locus-wide association and LD analyses identified intronic SNPs and haplotypes in the SEC8L1 gene that are strongly associated with RA. We propose that SEC8L1, which encodes a component of the exocyst complex, is a candidate susceptibility gene for RA in the Japanese population.

Adult↗
PubMed2005

Asynchronous progressive diaphyseal dysplasia.

We report the case of a 42-year-old Japanese woman with unusual diaphyseal dysplasia of bilateral femora. Radiographs showed thickening and sclerosis of the cortex with resultant enlargement of the diaphysis, unclear demarcation of the surface of the cortex, and no periosteal reaction. These changes were found on the left femur at the first presentation, and those on the right femur developed within several years. Although this patient partly presented characteristics of Ribbing disease and Camurati-Engelmann disease, the focal involvement of bilateral femora suggested an unknown pathogenesis.

Journal Article↗
PubMed2005

Total hip arthroplasty in osteopetrosis using computer-assisted fluoroscopic navigation.

Hybrid total hip arthroplasty with computer-assisted fluoroscopic navigation was performed on a patient with osteoarthritis due to an autosomal dominant form of osteopetrosis. The surgical procedures were difficult because the bone was extremely hard and brittle with obliteration of the medullary cavity. Especially, preparation of a femoral canal for the stem was technically challenging and required changes from a conventional surgical procedure. Therefore, we used a computer-assisted fluoroscopic navigation system to create the femoral cavity for the stem, and an accurate placement of the prosthesis was achieved. Navigation guidance can be a useful tool when performing arthroplasty in patients with hip osteoarthritis associated with osteopetrosis.

Arthroplasty, Replacement, Hip↗
PubMed2005

Cyclooxygenase-2 inhibitor delays fracture healing in rats.

BACKGROUND: Cyclooxigenase-2 (COX-2) inhibitors have been reported to delay fracture healing. To investigate the major inhibitory period of COX-2 inhibitors in fracture healing, we administrated etodolac, a COX-2-specific inhibitor, to a rat fracture model by altering the period of administration from early to late. METHOD: After closed fractures had been created at the middle of the femoral shafts in 12-week-old Wister rats, a standardized dose of etodolac was administrated in three ways: group I received it for 3 weeks, group II for just the first week after operation, and group III for just the third (final) week. Group IV was the vehicle control group. Bone maturation was estimated by radiographic scoring system, and mechanically by a three-point bending test. RESULTS AND INTERPRETATION: In both the radiographic and mechanical studies, groups I and II showed lower scores than group IV, indicating that even a short period of administration of a COX-2-specific inhibitor in the early phase of fracture healing creates a risk of delayed healing. blacksquare, square, filled.

Animals↗
PubMed2005

Osteoactivin upregulates expression of MMP-3 and MMP-9 in fibroblasts infiltrated into denervated skeletal muscle in mice.

In this study, we examined pathophysiological roles of osteoactivin, a functionally unknown type I membrane glycoprotein, in mouse skeletal muscle atrophied by denervation (sciatic neurectomy). Denervation increased the amounts of osteoactivin, vimentin, matrix metalloproteinase-3 (MMP-3), and MMP-9 in mouse gastrocnemius muscle. Interestingly, immunohistochemical analysis revealed that vimentin, MMP-3, and MMP-9 were mainly present in fibroblast-like cells infiltrated into denervated mouse gastrocnemius muscle, whereas osteoactivin was expressed in the sarcolemma of myofibers adjacent to the fibroblast-like cells. On the basis of these findings, we reasoned that osteoactivin in myocytes was involved in activation of the infiltrated fibroblasts. To address this issue, we examined effects of osteoactivin on expression of MMPs in fibroblasts in vitro and in vivo. Overexpression of osteoactivin in NIH-3T3 fibroblasts induced expression of MMP-3, but not in mouse C(2)C(12) myoblasts, indicating that osteoactivin might functionally target fibroblasts. Treatment with recombinant mouse osteoactivin increased the amounts of collagen type I, MMP-3, and MMP-9 in mouse NIH-3T3 fibroblasts. The upregulated expression of these fibroblast marker proteins was significantly inhibited by heparin, but not by an integrin inhibitor, indicating that a heparin-binding motif in the extracellular domain might be an active site of osteoactivin. In osteoactivin-transgenic mice, denervation further enhanced expression of MMP-3 and MMP-9 in fibroblasts infiltrated into gastrocnemius muscle, compared with wild-type mice. Our present results suggest that osteoactivin might function as an activator for fibroblasts infiltrated into denervated skeletal muscles and play an important role in regulating degeneration/regeneration of extracellular matrix.

Animals↗
PubMed2004

Vertebral forward slippage in immature lumbar spine occurs following epiphyseal separation and its occurrence is unrelated to disc degeneration: is the pediatric spondylolisthesis a physis stress fracture of vertebral body?

STUDY DESIGN: Radiographic and histologic evaluation of a rat model of lumbar spine slippage. OBJECTIVES: To clarify the pathomechanism of slippage in the immature spine. SUMMARY OF BACKGROUND DATA: There are controversial hypotheses regarding the pathogenesis of slippage of the pediatric spine with pars defects. Some studies supported that disc degeneration was its cause, while others indicated the growth plate injury was the cause. METHODS: An immature lumbar spine slippage model in 4-week-old rats was used. Following posterior destabilizing surgery, the lumbar spine was radiographically and histologically examined at 1, 3, 5, and 7 days after surgery. RESULTS: Radiographically, slippage occurred about 7% in the % slip on day 7, and no slippage was observed before day 5. Histologically, epiphyseal separation also appeared on day 7; before day 5, the growth plate showed no abnormalities. Within 7 days after the operation, the anulus fibrosus did not show any sign indicating degeneration. The nucleus pulposus was also normal up to day 7. CONCLUSION: The findings of this study support the hypothesis that vertebral forward slippage of the immature spine occurs following epiphyseal separation and its occurrence is unrelated to disc degeneration.

Animals↗
PubMed2004

Skeletal muscle gene expression in space-flown rats.

Skeletal muscles are vulnerable to marked atrophy under microgravity. This phenomenon is due to the transcriptional alteration of skeletal muscle cells to weightlessness. To further investigate this issue at a subcellular level, we examined the expression of approximately 26,000 gastrocnemius muscle genes in space-flown rats by DNA microarray analysis. Comparison of the changes in gene expression among spaceflight, tail-suspended, and denervated rats revealed that such changes were unique after spaceflight and not just an extension of simulated weightlessness. The microarray data showed two spaceflight-specific gene expression patterns: 1) imbalanced expression of mitochondrial genes with disturbed expression of cytoskeletal molecules, including putative mitochondria-anchoring proteins, A-kinase anchoring protein, and cytoplasmic dynein, and 2) up-regulated expression of ubiquitin ligase genes, MuRF-1, Cbl-b, and Siah-1A, which are rate-limiting enzymes of muscle protein degradation. Distorted expression of cytoskeletal genes during spaceflight resulted in dislocation of the mitochondria in the cell. Several oxidative stress-inducible genes were highly expressed in the muscle of spaceflight rats. We postulate that mitochondrial dislocation during spaceflight has deleterious effects on muscle fibers, leading to atrophy in the form of insufficient energy provision for construction and leakage of reactive oxygen species from the mitochondria.

Adaptor Proteins, Signal Transducing↗
PubMed2004

Development of autoimmune arthritis with aging via bystander T cell activation in the mouse model of Sjögren's syndrome.

OBJECTIVE: A wide spectrum of extraglandular manifestations may occur in patients with Sjogren's syndrome (SS), but the mechanisms responsible for in vivo progression are still obscure. We undertook this study to evaluate the age-related changes during the development of extraglandular autoimmune lesions, including arthritis, in the murine model of primary SS, and to evaluate the possible relationship between age-related disturbance of activation-induced cell death and the in vivo kinetics against autoantigens. METHODS: A total of 126 NFS/sld mice were investigated at ages 2, 4, 6, 10, 12, 18, 20, and 24 months. Cytokine production was tested using culture supernatants from anti-CD3 monoclonal antibody-stimulated T cells. Anti-single-stranded DNA (anti-ssDNA) antibodies, Ig isotypes (IgG1, IgG2a), rheumatoid factor (RF), and anti-type II collagen (anti-CII) antibodies were detected by enzyme-linked immunosorbent assay. Proliferative T cell responses against each of 3 recombinant alpha-fodrin proteins and against CII were analyzed. RESULTS: Autoimmune arthritis developed in SS model mice until age 24 months. Significant elevations in serum levels of RF, anti-ssDNA antibodies, and anti-CII antibodies were found in aging SS model mice. A high titer of serum autoantibodies against alpha-fodrin fragments (containing different epitopes that were originally identified in primary SS model mice) was frequently detected in young and aged SS model mice. Moreover, we found that alpha-fodrin autoantigen induced Th1 immune responses and accelerated disturbance of Fas-mediated T cell apoptosis in aged SS model mice. CONCLUSION: These results indicate that age-related disturbance of activation-induced cell death via bystander T cell activation may play a crucial role in the development of autoimmune arthritis in a murine model of SS.

Aging↗
PubMed2004

Influence of age on scapulo-thoracic orientation.

BACKGROUND: Scapular activity during shoulder motion is critical for normal shoulder function. With aging, muscle function deteriorates in almost all people, which may lead to shoulder impingement syndrome. METHODS: Forty-four normal subjects, 23 men and 21 women aged from 16 to 73 years with a mean age 48, were enrolled in the study. Static antero-posterior radiography at both 0 degrees and 90 degrees of abduction were undertaken and correlation between age and scapular orientations were evaluated by Pearson's correlation coefficient test. The purpose of this study is to investigate the relationship between aging and scapulo-thoracic orientation. FINDINGS: Significant correlation coefficients were observed between aging and scapular orientations. With the shoulder at 0 degrees abduction, posterior tilt showed significant negative correlation with aging. At 90 degrees abduction, both posterior tilt and upward rotation angle correlated negatively with aging. The correlation was apparent at 90 degrees abduction. INTERPRETATION: The results indicate that shoulder aging closely relates to changes of scapular orientation, which consist of decreases of the posterior tilt at 0 degrees and 90 degrees abduction and the upward rotation angle at 90 degrees. The current study indicated that one of the effects of aging on the shoulder is a decrease of posterior tilt and upward rotation angle as seen in an abducted position; and that these alterations are similar to the scapular kinematics of shoulder impingement syndrome. By taking this concept into consideration, the effects of aging on shoulder kinematics can be appropriately evaluated.

Adolescent↗
PubMed2004

Continuous muscle stretch prevents disuse muscle atrophy and deterioration of its oxidative capacity in rat tail-suspension models.

OBJECTIVE: The purpose of this study was to evaluate the effect of continuous muscle stretch on disuse-atrophied muscles. DESIGN: Sprague-Dawley rats were used and divided into five groups: control group, hind limb suspended for 3 and 7 days, and hind-limb suspension plus strenuous continuous muscle stretch for 3 and 7 days. In the hind-limb suspension plus strenuous continuous muscle stretch groups, the gastrocnemius-plantaris-soleus muscles were stretched using a plastic plate that immobilized the ankle joint at the maximum dorsal flexed position during the hind-limb suspension period. The intracellular energy metabolism of the working muscle during electric stimulation was evaluated by phosphorus-31 magnetic resonance spectroscopy in vivo. Changes in phosphocreatine, inorganic phosphate, and the intracellular pH were monitored to evaluate intramuscular oxidative capacity. Maximum tension and muscle wet mass were also measured. RESULTS: The oxidative capacity, muscle wet weight, and maximum tension decreased after hind-limb suspension. The muscle oxidative capacity at control levels was maintained during the first 3 days in muscles subjected to continuous strenuous stretch. It was also effective to prevent the decrease in muscle mass and maximum twitch tension during the initial 3 days. However, the effects did not persist. CONCLUSION: Continuous strenuous stretch was effective to prevent disuse muscle atrophy and its functional deterioration; however, its effects did not last long.

Animals↗
PubMed2004

Biophysic evaluation of bone quality-application of Fourier transform infrared spectroscopy and phosphorus-31 solid-state nuclear magnetic resonance spectroscopy.

In this review, we focus on findings obtained with biophysic techniques, Fourier transformed infrared (FTIR) spectroscopy and phosphorus-31 solid-state nuclear magnetic resonance (31P solid-state NMR) spectroscopy, which may allow us to evaluate bone quality and to predict bone strength. FTIR measures the absorption energy that produces an increase in the vibrational or rotational energy of atoms or groups of atoms within the molecule. FTIR spectroscopy allows us to examine the relative amount of minerals and matrix content and the arrangement of apatite and organic matrix. FTIR spectroscopy should become an important tool, because the relative amount of minerals and the arrangement of apatite and organic matrix could be a measure for evaluating bone quality. 31P solid-state NMR spectroscopy is useful for evaluating the quality of bone and predicting bone strength by calculating the spine-lattice relaxation time (T1) of bone. 31P solid-state NMR imaging can be used to measure quantitatively the mass of hydroxyapatite. The T1 relaxation time of both bone and deficient hydroxyapatite was much longer than that of pure hydroxyapatite. T1 relaxation time is one of the promising indices of bone quality.

Animals↗
PubMed2004

Relationship between cathepsin B and thrombin in rheumatoid arthritis.

OBJECTIVE: To investigate the pathophysiological significance of cathepsin B and thrombin in synovial fluid (SF) from patients with rheumatoid arthritis (RA). METHODS: Thrombin and cathepsin B activities of samples from patients with RA and osteoarthritis (OA) were measured using fluorogenic synthetic substrates. The concentration of interleukin 8 (IL-8) in SF was measured by ELISA. The effect of thrombin on the proliferation of synovial fibroblast-like cells (SFC) was examined by measuring 3H-thymidine incorporation. The effect of thrombin on the release of IL-8 and cathepsin B from SFC was investigated. The expression of IL-8 mRNA in SFC after stimulation with thrombin was evaluated using real-time quantitative RT-PCR. The effect of recombinant IL-8 on the activation of cathepsin B was examined using the knee joints of rabbits. RESULTS: In SF supernatants, cathepsin B and thrombin-like activity was significantly higher in RA than in OA, and there was a significant correlation between them. Cathepsin B activity was also significantly higher in SF cells and synovial tissue extracts from RA patients than in those from OA patients. There was a significant correlation between cathepsin B activity and the concentration of IL-8 in RA SF. Thrombin enhanced the proliferation of SFC in a dose-dependent manner. Thrombin significantly enhanced the release of IL-8 from SFC as well as the expression of IL-8 mRNA in SFC. IL-8 induced activation of cathepsin B in the knee joints of rabbits. However, thrombin did not directly increase cathepsin B activity in SFC. CONCLUSION: In RA, thrombin was found to be related to the enhanced growth of SFC and the release of IL-8 from these cells; thus thrombin is probably related to worsening of inflammation through the recruitment of leukocytes (neutrophils), which release cathepsin B into the SF. Thrombin can induce activation of cathepsin B in SFC via increased expression of IL-8.

Adult↗
PubMed2003

Intracapsular hip fractures in patients with rheumatoid arthritis.

We reviewed the treatment of 43 patients with rheumatoid arthritis and femoral neck fracture. Patients' average age was 66.4 (36-80) years and average duration of RA was 20.3 (4-42) years. Thirteen patients were treated with primary total hip arthroplasty (THA), and the clinical results were comparable to patients treated conservatively or by osteosynthesis. Eighteen patients were treated with primary bipolar hip prosthesis and after an average of 6.1 (1-13) years there was no acetabular destruction. However, long-term results were inferior to patients treated with THA. Nine patients were treated with osteosynthesis, of which two later had a hip prosthesis. Three cases with impacted fractures were treated conservatively with successful union in all.

Adult↗