PubMed Health⌕ Search

Biomedical subjects

K Matsuzaka

Publications and source records attributed to K Matsuzaka.

8 recordsLinked to original sources
PubMed2002

Bone response to calcium phosphate-coated and bisphosphonate-immobilized titanium implants.

Thin calcium phosphate (Ca-P) coatings have been introduced to overcome the shortcomings of plasma-sprayed Ca-P coatings. In our previous experiments, thin Ca-P coatings also enabled the immobilization of bisphosphonate, which is a drug used to treat osteoporosis. The present study was designed to evaluate the bone response to titanium implants treated with a thin Ca-P coating and bisphosphonate. Forty cylindrical commercially pure titanium implants with a length of 7 mm and a diameter of 3 mm were used as test implant fixtures. Three groups of surface-treated implants were prepared: (1) blasted with titanium powder and etched with a solution of 10% HF + 5% HNO3 (control); (2) modified with 0.5-microm thick Ca-P coatings and rapid heat-treating, and (3) immobilized with bisphosphonate by immersion in pamidronate disodium solution (10(-2) M) for 24 h at 37 degrees C. These surface-treated implants were inserted into edentulous areas in the mandibular molar region of five beagle dogs. After implantation periods of 4 and 12 weeks, the bone implant interface was evaluated histologically and histomorphometrically. All measurements were statistically evaluated using a one-way ANOVA and Fisher PLSD test for multiple comparisons among the means. Four weeks after the implantation, higher percentage of bone contact was found around the thin Ca-P-coated implants compared to that of the control group. The highest percentage of bone contact was found around the bisphosphonate-immobilized implants after 12 weeks of implantation. These data suggest that a thin coating of calcium phosphate followed by bisphosphonate-immobilization is effective in the promotion of osteogenesis on surfaces of dental implants.

Animals↗
PubMed2002

Cell proliferation and cell death in periodontal ligaments during orthodontic tooth movement.

The purpose of this study was to investigate cellular responses of periodontal ligaments during tooth movement. Twenty-eight male Sprague-Dawley rats, weighing 200-250 g each, were used. To create the orthodontic force, elastic rubber blocks (0.65 mm thick) were inserted between the maxillary first and second molars on both sides. On days 3, 7, 10, 14, 21 and 28 after rubber block insertion, histopathological changes in both the tension and the pressure sides were examined by immunohistochemistry using proliferating cell nuclear antigen (PCNA) and by the TUNEL method. The ratios of PCNA-positive cells on the tension side 3 and 7 days after rubber block insertion were higher than those on the pressure side. The ratios of PCNA-positive cells on the tension side were highest at day 3 after insertion and then decreased during the remainder of the experimental period. On the pressure side, the ratios of PCNA-positive cells increased up to day 10 post insertion, then decreased from 14 to 28 days. The ratios of TUNEL-positive cells on both the tension and the pressure sides increased throughout the entire experimental period. These results indicate that the periodontal ligaments on the tension side are able to respond more promptly to orthodontic forces than those on the pressure side. The data also suggest that the ratios of cell proliferation and of cell death are closely related to the regeneration and reconstruction of periodontal ligaments which reflect the orthodontic force.

Animals↗
PubMed2001

Characteristics of newly formed bone during guided bone regeneration: observations by immunohistochemistry and confocal laser scanning microscopy.

The purpose of this study was to investigate the characteristics of new bone formation during guided bone regeneration (GBR) using immunohistochemistry and confocal laser scanning microscopy. e-PTFE membranes were applied to defects created in the tibiae of rats, and some animals were sacrificed 6, 8, or 10 days later. Serial paraffin sections were cut, stained with H-E, and examined to analyze the ratio of new bone formation. Immunohistochemical staining with a monoclonal antibody specific for PCNA was used to evaluate the proliferating activity. In other experimental rats, calcein was injected at 6, 8, and 10 days after the surgery, and the animals were sacrificed 48 hr after injection. Their tibiae were removed, and Villanueva bone staining was performed before observation using confocal laser scanning microscopy to investigate the mineralization of new bones. The bone occupation ratio increased day by day, but the experimental groups had significantly higher ratios than control groups (without membrane) at each of the time periods. However, PCNA positive cells decreased over time in all groups, and there were no significant differences among the groups. Mineralization occurred more rapidly in the experimental groups than in the control groups. These results suggest that GBR accelerates the migration of osteogenic cells, the formation of new bone, and mineralization in the defect created by the e-PTFE membrane.

Animals↗
PubMed2001

A case of an ameloblastic fibro-odontoma arising from a calcifying odontogenic cyst.

This case report describes an ameloblastic fibro-odontoma arising from a calcifying odontogenic cyst (COC) in the mandible of a twenty-three-year old male. The patient was referred to the Department of Oral Surgery, Tokyo Dental College, on March 30th, 2000, complaining of a painful swelling, which had appeared three weeks earlier on his left mandibular molar region. In a pathological view, the lesion was a round cyst the size of a chicken-egg, dark red in color, and surrounded by a thick membrane. The cyst had an epithelium of varying thickness which included many ghost cells and an enamel-like structure on the inside, and a thick wall of connective tissue with an ameloblastic fibro-odontoma on the outside. Enamel organ-like epithelial islands were structured radially in the form of strands with immature dentin. Cytokeratin 19 was strongly immunoreactive in the epithelium of the lesion; osteopontin and osteocalcin reacted in the mesenchymal cells and weakly in the epithelial element of this tumor.

Adult↗
PubMed2000

Effect of microgrooved poly-l-lactic (PLA) surfaces on proliferation, cytoskeletal organization, and mineralized matrix formation of rat bone marrow cells.

Previous experiments showed that microgrooved substrate surfaces can influence the in vitro behavior of osteoblast-like rat bone marrow (RBM) cells. Cellular morphology and matrix deposition can be directed by substrate chemistry and topography. RBM cells cultured on poly-l-lactic acid (PLA) exhibit increased mineralization and alkaline phosphatase activity compared to polystyrene substrates. Consequently, the purpose of the present in vitro study is to further evaluate the behavior of RBM cells on microgrooved (groove depth 0.5 to 1.5 microns, groove and ridge width 1 to 10 microns) polystyrene (PS) and PLA surfaces. Besides grooved, also smooth control surfaces were made. Our results confirmed that microtextured surfaces are capable of influencing the behavior of the osteoblast-like RBM cells in vitro. Microtopography did not influence the RBM proliferation rate, or cellular actin organization. However, confocal laser scanning microscopy showed that cellular attachment is dependent on the applied material. Also clear differences were found between textured PS and PLA, with regard to the calcium content. We therefore conclude, that the application of microtextures could possibly influence the bone regeneration around biodegradable PLA devices.

Absorbable Implants↗
PubMed1999

The effect of poly-L-lactic acid with parallel surface micro groove on osteoblast-like cells in vitro.

In this study we evaluated the behavior of rat bone marrow (RBM) cells on microgrooved poly-L-lactic acid (PLA) and polystyrene (PS) surfaces. The applied groove depth was 0.5, 1.0 or 1.5 microns, with a groove and ridge width of 1, 2, 5 or 10 microns. Scanning electron microscopical examination showed that a collagen-rich mineralized layer of extracellular matrix (ECM) was deposited. Alignment of the cells and matrix to the surface grooves was observed as described before. Quantitative evaluation, using a tetracycline labeling assay, revealed that more mineralized ECM was formed on the PLA than on the PS. Further, PLA surfaces with a groove depth of 1.0 micron and groove widths of 1 and 2 microns induced most mineralized ECM. Finally, alkaline phosphatase activity was also higher on most microgrooved PLA surfaces, compared with the other materials. On the basis of these observations, we concluded that microtextured surfaces are able to influence the differentiation of osteoblast-like cells and the deposition of mineralized matrix. Probably, this phenomenon can be used to increase the bone regeneration around oral implants.

Alkaline Phosphatase↗
PubMed1998

Multiple giant angiomyolipomas with a polygonal epithelioid cell component in tuberous sclerosis: an autopsy case report.

A recent case of angiomyolipoma (AML) with a prominent component of polygonal epithelioid cells is described. A 27-year-old Japanese male with tuberous sclerosis presented with massive abdominal tumors increasing progressively in size. The patient died of respiratory disturbance and the autopsy revealed massive tumors in the bilateral kidneys, liver and lymph nodes, subependymal giant cell glioma of the brain and lymphangiomyomatosis of the lungs. The giant tumors were an unusual type of AML with a component of polygonal epithelioid cells, which showed a hepatocellular carcinoma-like pattern in some areas. Smooth muscle components comprising spindle cells, short or plump spindle cells and polygonal epithelioid cells frequently exhibited positive staining for HMB-45 but negative staining for epithelial cell markers. The unusual AML presented in this case was thought to be of low-grade malignancy and slow growing. It has been suggested that angiomyolipomas with diffuse areas of epithelioid cell component are potentially malignant. Immunostainings positive for HMB-45 but negative for epithelial cell markers are considered to be useful in differentiating AML with polygonal epithelioid cell component from other tumors, especially from renal cell carcinoma and hepatocellular carcinoma.

Adult↗