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ABSTRACT: This study compares the effect of bisphosphonate and intermittent PTH administration on haversian remodeling in cortical bone allografts in rabbits.
An intercalary heat-treated cortical bone allograft was applied to a segment skeletal defect in the left femur of Japanese white rabbits. The rabbits were randomly assigned to one of three groups: the vehicle control group (CNT); the bisphosphonate group (B group); and the intermittent PTH treatment group (P group). Periodic radiographic evaluation was performed and peripheral quantitative computerized tomography (pQCT) was used to evaluate the total bone area (Area), bone mineral density (BMD), and bone mineral content (BMC). The allografts also underwent histological examination.
The P group was radiographically superior in the latter stage, compared with the other groups. pQCT analysis of the allografts showed that the B group had a significantly higher Area and BMC. These parameters in the latter stage were significantly lower in the P group than in the other groups. The allograft of the B group was histologically mostly necrotic bone, whereas allograft of the P group showed abundant newly formed bone.
In rabbits, bisphosphonate prevents resorption, but suppresses remodeling and incorporation; by contrast, PTH increases resorption and accelerates allograft remodeling and incorporation. Based on our preliminary data, we suggest that further research on the manner of administration of bisphosphonate and PTH - which have contrasting effects - can be beneficial in maintaining bone strength and in regulating remodeling and allograft incorporation.
Journal of endocrinological investigation 05/2011; 35(2):139-45. · 1.57 Impact Factor
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ABSTRACT: Transformed sarcomas rarely arise from bone infarct lesions, although the majority of bone sarcomas are primary in origin. However, the pathogenesis of the condition is unknown. In this report, we describe a malignant fibrous histiocytoma with a p53 gene mutation. A 59-year-old woman complained of having pain in her left knee for three months. Plain radiographs of the distal metaphysis of her left femur revealed an ill-defined lytic lesion, which was consistent with a malignant tumor in the infarct lesion. An open biopsy specimen did not show any evidence of malignancy. Immunohistochemical examination of the biopsy specimen failed to show p53 protein-positive cells. However, a mutation in the p53 gene was detected when polymerase chain reaction/single-strand conformation polymorphism (PCR-SSCP) analysis was performed. A functionally relevant p53 missense mutation in codon 273 of exon 8 [CGT (Arg) -> CAT (His)] was confirmed by direct sequencing. We concluded that this lesion was a malignant bone tumor arising from the bone infarct lesion, and we thus performed a wide resection. The histopathological diagnosis of the resected specimen was that it was a malignant fibrous histiocytoma associated with bone infarction. Immunohistochemistry revealed that the tumor cells were positive for the p53 protein. To our knowledge, our patient is the first patient having a bone infarct-associated sarcoma with a p53 gene mutation. Identification of the p53 mutation helps in diagnosing the malignant transformation of the bone infarct lesion. One pathogenesis of this condition may be a mutation in the p53 gene.
The Tohoku Journal of Experimental Medicine 01/2011; 225(3):215-20. · 1.24 Impact Factor
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ABSTRACT: We examined trabecular and cortical bone in the senescence-accelerated mouse prone 6 (SAMP6) murine model of senile osteoporosis after treatment with human PTH 1-34. Sixteen-week-old female SAMP6 mice were assigned to control and PTH groups. PTH (20 microg/kg) was administered sc 3 times a week for 12 weeks. The control mouse strain, senescence-accelerated mouse resistant 1 (SAMR1), was used for comparison. The femoral metaphysis and diaphysis were used to measure bone mineral density (BMD), analyze the trabecular and the cortical structure by micro-computed tomography, and for conducting the bone strength test. PTH significantly attenuated the loss of BMD, improved the trabecular bone microstructure, and increased the bone strength in the femoral metaphysis. We did not find any differences in the bone strength of the femoral diaphysis after PTH treatment, although the cortical bone volume and cortical thickness were improved. Although the cortical thickness increased, the cortical bone density decreased, likely because of the increase of cortical porosity in the distal metaphysis after administration of PTH.
Journal of endocrinological investigation 11/2009; 33(6):395-400. · 1.57 Impact Factor
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ABSTRACT: The incidence of arthritic diseases is rapidly increasing in most advanced countries. Articular cartilage, which is the most important tissue in the joint, consists of chondrocytes and abundant extracellular matrix, including aggrecan, and shows poor self-repair. We studied the potential of stem cells in mouse subcutaneous adipose tissue as a source of cells to regenerate cartilage tissue. Analysis of adipose-derived stromal vascular fraction culture cells (ADSVFs) using mesenchymal stem cell markers showed that CD90-positive cells accounted for 93.8%, CD105-positive cells for 68.5%, and p75 neurotrophin receptor (p75NTR, CD271)-positive cells for 36.1%. These results indicate that cells positive for mesenchymal stem cell markers are present in ADSVFs. The CD105-positive or -negative cells were isolated from ADSVFs by magnetic cell separation (MACS), and the efficiency of differentiation into chondrocytes was compared with using three methods of pellet method, gel-coating method, and gel-embedding sheet method. Using the CD105-positive cells and the gel-embedding sheet method, aggrecan mRNA was detected about three times higher than pellet and gel-coating methods. The above data suggest that ADSVFs could be differentiated into chondrocyte-like cells in the gel-embedding sheet method and could be useful in regenerative medicine to treat cartilage defects or cartilage degenerative disease. The use of cells sorted by mesenchymal stem cell markers from adipose tissue would gain position in the repair of cartilage tissue.
The Tohoku Journal of Experimental Medicine 11/2008; 216(2):149-56. · 1.24 Impact Factor
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ABSTRACT: We present a rare concurrence of enchondroma and periosteal chondroma in the right distal fibula that mimicked chondrosarcoma in a 13-year-old boy. Radiographs and CT scans showed a periosteal lesion producing saucerization without periosteal reaction and calcification in the distal metaphysis of the right fibula. MRI showed an intramedullary lesion adjacent to the periosteal lesion, although it was invisible at CT. There was no cortical breach on imaging and gross examination. Because both lesions represented benign cartilaginous tumors on histology, concurrent periosteal chondroma and enchondroma of the fibula was diagnosed. This combination in the same bone in a patient without enchondromatosis is exceedingly rare. Such imaging features may be confused with those of chondrosarcoma.
Skeletal Radiology 06/2006; 35(5):302-5. · 1.54 Impact Factor
