Masaji Morita

Gifu University, Gihu, Gifu, Japan

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Publications (4)6.89 Total impact

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    ABSTRACT: Calpain is secreted by intra-articular synovial cells and degrades the main components of cartilage matrix proteins, proteoglycan, and collagen, causing cartilage destruction. Matrix metalloproteinase-3 (MMP-3) has also been detected in synovial fluid and serum, and is involved in the development and progression of rheumatoid arthritis by degradation of the extracellular matrix and cartilage destruction. To investigate the relationship between calpain and MMP-3 in rheumatic inflammation, we utilized the rheumatic synovial cell line, MH7A. Tumor necrosis factor (TNF-alpha) stimulation-induced increased expression of mu-calpain, m-calpain, and MMP-3 in these cells, as well as the release of calpain and MMP-3 into the culture medium. The calpain inhibitors, ALLN (calpain inhibitor I) and calpeptin, did not affect the intracellular expression of MMP-3, but reduced the secretion of MMP-3 in a concentration-dependent manner. Down-regulation of mu- but not m-calpain by small interfering RNAs abolished TNF-alpha-induced MMP-3 release from the synovial cells. These findings suggest that calpain, particularly mu-calpain, regulates MMP-3 release by rheumatic synovial cells, in addition to exerting its own degradative action on cartilage.
    No preview · Article · Jun 2006 · Biochemical and Biophysical Research Communications
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    ABSTRACT: We report a displaced femoral shaft fracture that occurred with no sign of contact-induced, stress, fatigue, or previous abnormal bone pathology in a 19-y-old man who kicked the ground instead of the ball when playing soccer. After examination to rule out abnormal bone pathology, intramedullary nailing was performed. Bone union was achieved and he could return to recreational soccer. Among soccer injuries, the occurrence of displaced femoral shaft fractures in the absence of stress, fatigue, or pathological fracture is rare. Awareness of such a rare cause of displaced femoral shaft fracture would help clinicians in the field of sports and soccer medicine. Key PointsWe report a very rare displaced femoral shaft fracture in a 19-y-old man who kicked the ground instead of the ball when playing soccer.Abnormal bone pathology was ruled out.Awareness of such a rare cause of displaced femoral shaft fracture would help clinicians in the field of sports and soccer medicine.
    No preview · Article · Dec 2005 · Journal of sports science & medicine
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    ABSTRACT: A case of spondyloepiphyseal dysplasia congenita (SEDC) with thoracolumbar kyphosing scoliosis and a clinical outcome of the patient's surgical treatment are reported. We report a rare case and the effect of surgical treatment on the kyphosing scoliosis with SEDC with a review of literature. SEDC is a rare disease and has a variety of spinal deformities. To our knowledge, a case of surgical treatment for the kyphosing scoliosis with SEDC was not reported before. The patient, a 27-year-old woman, complained of severe back pain and dyspnea. She was operated on in 1997 for severe kyphosing scoliosis, using segmental spinal instrumentation and strut bypass graft. She was followed for 6 years, and clinical symptoms and plain X-ray films were investigated. Her kyphosis was corrected from 116 degrees to 86 degrees at the final follow-up; otherwise, her scoliosis was almost unchanged. Her symptoms were relieved. A case of SEDC with thoracolumbar kyphosing scoliosis was successfully treated by segmental spinal instrumentation and anterior strut bypass graft.
    No preview · Article · Mar 2005 · The Spine Journal
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    ABSTRACT: We have proved before that μ-calpain can be a promising autogenous agent to replace chymopapain in chemonucleolysis treatment. Even in the case of accidental intrathecal injection, the undesirable neural damage of calpain can be neutralized by normal cerebrospinal fluid (CSF). The aim of this study was to characterize this unknown calpain inhibitor-like component in the CSF of normal rabbits. A heat-stable low molecular weight fraction in the CSF was identified. It was not extracted by chloroform solution, but labile to protease digestion. It inhibited the calpain proteolysis of microtubule-associating protein-2 (MAP-2) and membrane structure proteins of platelets and PC12 cells. It can block the autolytic activation of native human erytluocyte μ-calpain, where the conversion of the large subunit of μ-calpain from the 80-kDa form to the 76-kDa form was obstructed, with accumulation of the intermediate 78-kDa form. A possible calpain inhibition mechanism was discussed. After purification by paper chromatography, gel filtration and reverse phase chromatography, the composition of the calpain inhibitor was investigated. An oligopeptide with molecular weight about 800 Da was identified as a novel calpain inhibitor by partial amino acid sequence.
    No preview · Article · Dec 2003 · Biomedical Research