Biomedical subjects

Ichiro Nishimura

Publications and source records attributed to Ichiro Nishimura.

6 recordsLinked to original sources

PubMed2003

Membrane type (MT) 1-matrix metalloproteinase (MMP) and MMP-2 expression in ligature-induced periodontitis in the rat.

BACKGROUND: Matrix metalloproteinases (MMPs) have been shown to be involved in the degradation of the extracellular matrix (ECM). In particular, MMP-2 and MMP-9 (gelatinase A and gelatinase B, respectively) have been identified as the predominant MMPs during periodontitis. Recent studies have indicated that a novel transmembrane MMP, mebrane-type 1 matrix metalloproteinase (MT1-MMP), can activate pro-MMP-2 in tumor metastasis. This study aims to elucidate the presence and localization of MT1-MMP and MMP-2 in periodontitis in a rat model. METHODS: In 2 groups of 40-day-old male Sprague-Dawley rats, periodontitis was initiated by ligating floss around maxillary second molars. A group of control animals were left untreated. Maxillary dentoalveolar segments were isolated after 7 and 21 days postinduction and were prepared for gross and radiographic analysis of bone loss and for histological analysis. Samples were also prepared for gel zymography to detect the presence of MMP-2, and for Northern blot analysis and in situ hybridization with MT1-MMP probes. RESULTS: MMP-2 expression increased at 21 days following ligature placement, in conjunction with MT1-MMP expression. MT1-MMP mRNA expression was observed in epithelial cells, fibroblasts, and in multinucleated cells in the periodontium. CONCLUSION: Our data suggest that MT1-MMP may play a role in extracellular matrix degradation during periodontitis, in concert with MMP-2 and other proteinases.

Animals↗

PubMed2002

The identification of novel wound-healing genes through differential display.

Effective methods to identify novel genes in complicated dynamic tissue processes are needed in molecular biology research. Traditional techniques primarily target known genes and are inefficient in the pursuit of unknown genes. Here we describe the use of a modified differential display polymerase chain reaction (DD-PCR) protocol for the identification of genes differentially expressed in wound healing. Full-thickness dorsal wounds were made on 35 adult rats, followed by wound harvest at 12 hours, 24 hours, 3 days, 5 days, 7 days, 10 days, and 14 days after injury. Modified DD-PCR was performed and gene fragments displaying definite changes during wound healing were cloned and sequenced. Gene fragments from DD-PCR were compared with available gene bank database sequences. Specific primer PCR was used to confirm DD-PCR expression patterns. As a result, over 1000 gene fragments were amplified by DD-PCR, 35 of which demonstrated distinct differences during repair. Cloning and sequencing of 13 of these gene fragments revealed that some were homologous to several characterized genes with previously unsuspected roles in repair, whereas others were completely novel genes with no known function. Specific primer PCR further confirmed expression of six of these 13 gene fragments. Only one of the 13 cloned fragments, later identified as interleukin-1beta, had well-recognized associations with tissue injury. Other fragments corresponded to various genes involved in cellular processes such as differentiation, proliferation, exocytosis, and myofibril assembly. No prior studies have linked them to wound healing. We have demonstrated that modified DD-PCR can be used to effectively identify novel genes differentially expressed during repair. Because DD-PCR allows for the simultaneous amplification of multiple arbitrary transcripts, it is a powerful genetic screening tool for complicated dynamic tissue processes, particularly when multiple, limited-sized samples are involved.

Animals↗

PubMed2002

Modulated bone matrix-related gene expression is associated with differences in interfacial strength of different implant surface roughness.

PURPOSE: The objective of this study was to examine the effect of implant surface topography on biomechanical strength and expression patterns of bone extracellular matrix (ECM)-related genes during implant healing. MATERIALS AND METHODS: Cylinder implants with turned or dual acid-etched (DE) surface were placed into the femurs of female Sprague-Dawley rats. At 2 and 4 weeks after the implantation, the implant push-in test was performed to measure the load-bearing strength of the bone-tissue interface. T-shaped hollow implants were separately placed and the total RNA was extracted from the ingrown tissue within the hollow chamber. The RNA was subjected to reverse transcriptase polymerase chain reaction to analyze the expression pattern of selected bone extracellular matrix-related genes. RESULTS: The push-in value of the DE implant is approximately 300% greater than that of the turned implant at weeks 2 and 4 (p=.0090). The expression of collagen II, osteocalcin and biglycan was higher in the week 2 DE implant group than the turned implant group. At week 4 the expression of collagen II and IX was 7- and 26-fold, respectively, greater in the DE implant group than in the turned implant group. CONCLUSIONS: The surface topography of implants may induce the phenotypic alteration of wound healing cells. The increased interfacial strength of the DE implant may be associated with the modulated expression of the selected set of bone extracellular matrix genes.

Acid Etching, Dental↗

PubMed2002

Craniosynostosis in transgenic mice overexpressing Nell-1.

Previously, we reported NELL-1 as a novel molecule overexpressed during premature cranial suture closure in patients with craniosynostosis (CS), one of the most common congenital craniofacial deformities. Here we describe the creation and analysis of transgenic mice overexpressing Nell-1. Nell-1 transgenic animals exhibited CS-like phenotypes that ranged from simple to compound synostoses. Histologically, the osteogenic fronts of abnormally closing/closed sutures in these animals revealed calvarial overgrowth and overlap along with increased osteoblast differentiation and reduced cell proliferation. Furthermore, anomalies were restricted to calvarial bone, despite generalized, non-tissue-specific overexpression of Nell-1. In vitro, Nell-1 overexpression accelerated calvarial osteoblast differentiation and mineralization under normal culture conditions. Moreover, Nell-1 overexpression in osteoblasts was sufficient to promote alkaline phosphatase expression and micronodule formation. Conversely, downregulation of Nell-1 inhibited osteoblast differentiation in vitro. In summary, Nell-1 overexpression induced calvarial overgrowth resulting in premature suture closure in a rodent model. Nell-1, therefore, has a novel role in CS development, perhaps as part of a complex chain of events resulting in premature suture closure. On a cellular level, Nell-1 expression may modulate and be both sufficient and required for osteoblast differentiation.

Adenoviridae↗

PubMed2002

Gene expression profiling by DNA microarray technology.

Methods in molecular and genetic biology have provided important clues to elucidate the complex mechanisms of oral and craniofacial development and pathogenesis of diseases. It has become increasingly clear that a biological phenotype is a result of multiple factors involving a large number of regulatory genes, while a single nucleotide mutation can cause various degrees of oral and craniofacial abnormalities. These oral and craniofacial problems often present a challenge to the molecular screening process. Recent advances in microarray-based technologies allow for large-scale gene expression analysis in a single experiment, which have been applied to genome-wide assays, mutational analysis, drug discovery, developmental biology, and molecular analysis of various diseases. This review introduces the basic principle and some modifications of techniques and materials used in microarray technology, as well as currently available microarray data analysis strategies. Microarray technology can be applied to the soon-to-be-available human genome database and will be a powerful research tool for those inquiring into specific problems associated with oral and craniofacial biology.

Animals↗

PubMedDate not supplied

Different bone integration profiles of turned and acid-etched implants associated with modulated expression of extracellular matrix genes.

PURPOSE: The manner in which surface roughness of Implants affects bone-implant integration remains unknown. This study correlated morphologic profiles of bone-implant integration and extracellular matrix (ECM) gene expression in response to the placement of implants with different surface topographies. MATERIALS AND METHODS: T-shaped hollow implants with turned and dual acid-etched (DE) surfaces were placed into rat femurs. A bone integration curve (BIC) was created from serial histomorphometric measurements within the implant chamber. The mRNA expression pattern of ECM genes in bone healing with or without implants was examined using reverse transcriptase-polymerase chain reaction. RESULTS: At week 2, the BIC of the DE implant increased near the implant surface, whereas that of the turned implant decreased. The bone-to-implant contact rate of the DE Implant was 6- and 2.5-fold higher than that of the tuned Implant at weeks 2 and 4, respectively. A spatially standardized histomorphometry revealed that, at week 2, the DE implant had a greater bone volume than the turned implant in a zone near the implant, but not in zones distant from the implant surface. The DE implant evoked an accelerated mRNA expression for osteonectin and osteocalcin compared with the turned Implant, along with an up-regulated expression for bone sialoprotein II, collagen III, and integrins in initial healing stages up to week 1. DISCUSSION AND CONCLUSION: The results indicate that different histologic bone integration profiles associated with increased surface roughness may be explained, in part, by the modulated expression of the selected ECM-related genes. The data provide evidence supporting the fact that gene regulation occurs at local levels of implant surfaces in vivo.

Analysis of Variance↗