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Biomedical subjects

Minoru Ueda

Publications and source records attributed to Minoru Ueda.

At least 55 records · Page 3Linked to original sources
PubMed2005

Clinical case reports of injectable tissue-engineered bone for alveolar augmentation with simultaneous implant placement.

This clinical study was undertaken to evaluate the use of tissue-engineered bone, mesenchymal stem cells, platelet-rich plasma, and beta-tricalcium phosphate as grafting materials for maxillary sinus floor augmentation or onlay plasty with simultaneous implant placement in six patients with 3- to 5-mm alveolar crestal bone height. All 20 implants were clinically stable at second-stage surgery and 12 months postloading. A mean increase in mineralized tissue height of 7.3+/-4.6 mm was evident when comparing the pre- and postsurgical radiographs. Injectable tissue-engineered bone provided stable and predictable results in terms of implant success.

Absorbable Implants↗
PubMed2005

Immunohistochemical localization of cytokeratin 19, involucrin and proliferating cell nuclear antigen (PCNA) in cultured human gingival epithelial sheets.

It has been suggested that human cultured gingival epithelial sheets may serve as a possible grafting material. The purpose of this study was to examine the biological characteristics of human cultured gingival epithelial sheets by epithelial differentiation and proliferation markers. Immunohistochemical localization of cytokeratin 19, involucrin and proliferating cell nuclear antigen (PCNA) were examined in human cultured gingival epithelial sheets samples from twenty patients. Cytokeratin 19-immunopositive cells were scattered mainly in the suprabasal layer. Immunoreactivity for involucrin was observed in all layers except for the basal layer. The majority of proliferating cell nuclear antigen-immunopositive cells was found in the basal layer. These results suggested that the cultured human gingival epithelial sheets were biologically active and in proliferative condition, which implies that this biological product may be a potential grafting material.

Adult↗
PubMed2004

Tissue-engineered composites of anulus fibrosus and nucleus pulposus for intervertebral disc replacement.

STUDY DESIGN: By the technique of tissue engineering, composite intervertebral disc implants were fabricated as novel materials for disc replacement, implanted into athymic mice, and removed at times up to 12 weeks. OBJECTIVES: The goal of this study was to construct composite intervertebral disc structures consisting of anulus fibrosus cells and nucleus pulposus cells seeded on polyglycolic acid and calcium alginate matrices, respectively. SUMMARY OF BACKGROUND DATA: Previous work has documented the growth of anulus fibrosus cells on collagen matrices and nucleus pulposus cells cultured on multiple matrices, but there is no documentation of composite disc implants. METHODS: Lumbar intervertebral discs were harvested from sheep spine, and the nucleus pulposus was separated from surrounding anulus fibrosus. Each tissue was digested in collagenase type II. After 3 weeks in culture, cells were seeded into implants. The shape of the anulus fibrosus scaffold was fabricated from polyglycolic acid and polylactic acid, and anulus fibrosus cells were pipetted onto the scaffold and allowed to attach for 1 day. Nucleus pulposus cells were suspended in 2% alginate and injected into the center of the anulus fibrosus. The disc implants were placed in the subcutaneous space of the dorsum of athymic mice and harvested at 4, 8, and 12 weeks. At each time point, 4 samples were stored in -70 degrees C for collagen typing and analysis of proteoglycan, hydroxyproline, and DNA. Other samples were fixed in 10% formalin for Safranin-O staining. RESULTS: The gross morphology and histology of engineered discs strongly resembled those of native intervertebral discs. Biochemical markers of matrix synthesis were present, increasing with time, and were similar to native tissue at 12 weeks. Tissue-engineered anulus fibrosus was rich in type I collagen but nucleus pulposus contained type II collagen, similar to the native disc. CONCLUSION: These results demonstrate the feasibility of creating a composite intervertebral disc with both anulusfibrosus and nucleus pulposus for clinical applications.

Animals↗
PubMed2004

The effect of the long-term cultivation on telomere length and morphology of cultured epidermis.

BACKGROUND: Cultured epidermis has been successfully used in clinical treatment such as burns and pigmentary disorders. Although the generation of wide cultured epidermis for clinical use may require repeated passages, especially for allografts, the effects of long-term cultivation on its quality and cell viability are not well known. OBJECTIVES: To investigate the changes in morphology, telomere length, and telomerase activity during the passages of cultured epidermis and keratinocytes up to the passage limit, and to examine the usefulness of telomere length as a performance criterion for cultured epidermis. METHODS: The keratinocytes obtained from five patients were used to generate cultured epidermis. At the early passage and after cultivation up to the passage limit, morphology, telomere length and telomerase activity were investigated by using microscopes, southern blot analysis and telomeric repeat amplification protocol assay, respectively. RESULTS: The cultured cells started to show morphological changes when each passage was close to its limit and the cell sheets assumed an irregular stratification with various sizes of cytoplasm and nuclei. At the passage limit, the telomere length had decreased approximately 80-85%, and the average telomerase activity had declined under serum-free culture conditions. CONCLUSION: The results of this study showed the morphological change and telomere length reduction by long-term cultivation on cultured epidermis. Although the reduction in telomere length and telomerase activity may not be the major cause of the senescence, they could provide a useful information for the quality of the cultured epidermis.

Cells, Cultured↗
PubMed2004

Accelerating effects of basic fibroblast growth factor on wound healing of rat palatal mucosa.

PURPOSE: In this study, basic fibroblast growth factor (bFGF) was examined for its ability to accelerate tissue repair in a rat oral mucosal wound. MATERIALS AND METHODS: A 4-mm mucosal defect was surgically made to the depth of the periosteum in a rat palate. bFGF was injected along the edge of the mucosal defect immediately after surgery. A control group received only phosphate-buffered saline vehicle. RESULTS: bFGF significantly accelerated granular tissue formation and reepithelialization. From the histologic analysis, the bFGF-treated group showed relatively faster collagen maturation. Starting 3 days after surgery, fibroblast growth factor receptor 1 (FGFR1)-positive cells appeared in the granular and spinous cell layers of the reepithelializing mucosa in the bFGF-treated group, whereas almost none was observed in the intact oral mucosa. By day 5, FGFR1-positive cells were seen below the stratum corneum, even in the control group. However, the number and intensity of FGFR1-positive cells in the bFGF-treated group were greater than in the control group. Results of immunostaining against proliferating cell nuclear antigen showed that bFGF stimulated cell proliferation of the basal cell layer in the regenerating epithelium. At a higher dose of bFGF, proliferating cell nuclear antigen-positive cells were also observed in the submucosal connective tissue. CONCLUSION: By the induction of its ligand protein concomitant with direct effects such as increased granular tissue formation and reepithelialization, a single topical application of bFGF facilitated wound healing in rat oral mucosa. The results of this study support the consideration for bFGF application for patients with impaired healing of oral mucosal injury.

Analysis of Variance↗
PubMed2004

Cartilage formation by serial passaged cultured chondrocytes in a new scaffold: hybrid 75:25 poly(L-lactide-epsilon-caprolactone) sponge.

PURPOSE: This study was designed to determine whether multipled chondrocytes immersed in a new scaffold, 75:25 poly(L-lactide-epsilon-caprolactone) sponge coated with type I collagen (75-PLC scaffold), could be used to generate cartilage tissue in vivo and to evaluate the correlation between cartilage generation and the phenotype of the proliferated chondrocytes. MATERIALS AND METHODS: Rat chondrocytes were suspended in 75-PLC scaffold at a density of 1 x 10 7 cells/mL after proliferation in a monolayer for 1 (P1) to 4 passages (P4) and implanted in nude mice for 4 weeks. Cells were characterized by the expression of genes encoding type II collagen, aggrecan, and type I collagen by Northern hybridization, and consequently, the newly formed tissue was evaluated histologically. RESULTS: The expression of aggrecan messenger RNA gradually decreased with the passaged cultures; however, the expression of type I collagen messenger RNA increased with time. The cartilage formations in all specimens were found not only in P1 chondrocytes but also in P2 chondrocytes, although when P3 chondrocytes were grafted, approximately 50% of cartilage formation was still observed up to but not beyond P4. CONCLUSION: It is suggested that cartilage tissue is generated with cultured chondrocytes up to P2 but not beyond P4. Northern blot analysis is useful for the assessment of whether the cells are capable of regeneration.

Absorbable Implants↗
PubMed2004

Horizontal alveolar distraction of the narrow maxillary ridge for implant placement.

PURPOSE: The purpose of this report was to describe a surgical technique for performing horizontal alveolar distraction of the knife-edge maxillary ridge. PATIENT AND METHODS: The patient was a 17-year-old woman with atrophy of the alveolar rim in the anterior upper jaw, which had inadequate width for implant placement. The transport segment was constructed by the osteotomy of the labial cortex of the alveolus. A transport plate of a distractor (LEAD system; Stryker Leibinger, Kalamazoo, MI) was placed on the transport segment. The distraction rod was inserted horizontally, and put in contact with the palatal cortex at the top. A base plate was not placed. RESULTS: The alveolar distraction was successfully performed to gain 6.0 mm in width and 0.5 mm in height, allowing placement of three 14-mm implants. All the implants were integrated so as to support the prosthesis. CONCLUSIONS: Alveolar distraction can be useful for augmenting the narrow ridge horizontally and placement of implants.

Adolescent↗
PubMed2004

Elevated transcript level of hyaluronan synthase1 gene correlates with poor prognosis of human colon cancer.

Hyaluronan plays important roles in the complex processes of tumor invasion and metastasis. It is now known that three hyaluronan synthase (HAS) isoforms catalyze hyaluronan synthesis, which raises the question of how they are involved in malignant tumor progression. In this study, we examined the correlation between tumor progression and transcriptional levels of three HAS isoforms in specimens of human colon cancers. Tumor tissues from 31 patients with different diagnostic grades were assessed to determine the level of each HAS isoform by real time RT-PCR. The mean expression coefficients for HAS1, HAS2 and HAS3 in the cancerous parts were 0.82-, 0.91- and 1.22-fold, respectively; of those in the noncancerous parts at Dukes' stage A; 1.00-, 0.95- and 1.06-fold, respectively, at stage B; and 1.95-, 1.16- and 1.19-fold, respectively, at stage C. In survival analysis, a significant correlation was observed between poor survival and the HAS1 transcript level. When the ratio of tumor to normal tissue in the HAS1 level was compared with that of the HA receptor transcript level, there was a positive correlation with that of the CD44 variant 6 level at Dukes' stage C. Our current results therefore suggest that HAS1 plays a role in the malignant progression of human colon cancer cells.

Base Sequence↗
PubMed2004

Differential regulation by IL-1beta and EGF of expression of three different hyaluronan synthases in oral mucosal epithelial cells and fibroblasts and dermal fibroblasts: quantitative analysis using real-time RT-PCR.

Using "real-time RT-PCR", we assessed the expression of three different hyaluronan synthase genes, HAS1, HAS2, and HAS3, by measuring their mRNA amounts in cultured human oral mucosal epithelial (COME) cells, oral mucosal fibroblasts, and dermal fibroblasts, and investigated the effects of interleukin-1beta (IL-1beta) and epidermal growth factor (EGF). When COME cells were treated with IL-1beta or EGF, early and marked increases and subsequent rapid decreases were observed for all HAS genes and, moreover, actual changes in hyaluronan synthesis subsequently occurred. The effects of IL-1beta stimulation were concentration-dependent and the maximal response to the EGF stimulation was observed at a low concentration (0.1 ng per mL). When two different types of fibroblasts were treated with IL-1beta or EGF, increased expression with different degrees and rates of three different HAS genes and subsequent increased synthesis of hyaluronan were also observed. In addition, HAS1 gene expression was not detectable in the mucosal fibroblasts, while weak HAS3 gene expression was detected in the dermal fibroblasts. Taken together, it is likely that the regulation of the expression of the three different HAS genes is different between oral mucosa and skin, which may be of significance for elucidating some of the differences between these tissues in wound healing.

Cells, Cultured↗
PubMed2004

Tissue-engineered injectable bone regeneration for osseointegrated dental implants.

The present study investigated a correlation between osseointegration in dental implants and an injectable tissue-engineered bone, using mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP). Initially, the teeth in the mandible region were extracted and the healing period was 1 month. Bone defects on both sides of the mandible were prepared with a trephine bar. The defects were implanted with graft materials as follows: PRP, dog MSCs (dMSCs), and PRP, autogenous particulate cancellous bone and marrow (PCBM), and control (defect only). Two months later, the animals were evaluated by histology, and at the same time dental implants were installed. Two months later, the animals were sacrificed and nondecalcified sections were evaluated histologically and histometrically. According to the histological observations, the dMSCs/PRP group had well-formed mature bone and neovascularization, compared with the control (defect only) and PRP groups, as was the same for the PCBM group. A higher marginal bone level was observed around implants with PRP, PCBM, and dMSCs/PRP compared with the control. Furthermore, the values describing the amount of bone-implant contact (BIC) at the bone/implant interface were significantly different between the PRP, PCBM, dMSCs/PRP, and control groups. Significant differences were also found between the dMSCs/PRP and control groups in bone density. The findings of this experimental study indicate that the use of a mixture of dMSCs/PRP results in good results such as the amount of BIC and bone density comparable with that achieved by PCBM.

Animals↗
PubMed2004

Translational research for injectable tissue-engineered bone regeneration using mesenchymal stem cells and platelet-rich plasma: from basic research to clinical case study.

Translational research involves application of basic scientific discoveries into clinically germane findings and, simultaneously, the generation of scientific questions based on clinical observations. At first, as basic research we investigated tissue-engineered bone regeneration using mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) in a dog mandible model. We also confirmed the correlation between osseointegration in dental implants and the injectable bone. Bone defects made with a trephine bar were implanted with graft materials as follows: PRP, dog MSCs (dMSCs) and PRP, autogenous particulate cancellous bone and marrow (PCBM), and control (defect only). Two months later, dental implants were installed. According to the histological and histomorphometric observations at 2 months after implants, the amount of bone-implant contact at the bone-implant interface was significantly different between the PRP, PCBM, dMSCs/ PRP, native bone, and control groups. Significant differences were also found between the dMSCs/PRP, native bone, and control groups in bone density. These findings indicate that the use of a mixture of dMSCs/ PRP will provide good results in implant treatment compared with that achieved by autogenous PCBM. We then applied this injectable tissue-engineered bone to onlay plasty in the posterior maxilla or mandible in three human patients. Injectable tissue-engineered bone was grafted and, simultaneously, 2-3 threaded titanium implants were inserted into the defect area. The results of this investigation indicated that injectable tissue-engineered bone used for the plasty area with simultaneous implant placement provided stable and predictable results in terms of implant success. We regenerated bone with minimal invasiveness and good plasticity, which could provide a clinical alternative to autogenous bone grafts. This might be a good case of translational research from basic research to clinical application.

Aged↗
PubMed2004

A quantitative study of nerve fiber density in the submandibular gland of rats.

The route and three dimensional distribution of nerve terminals in the submandibular gland were investigated in rats using immunohistochemistry for the protein gene product (PGP) 9.5, as a marker of neuronal elements. Thick fiber bundles were found along the wall of the excretory duct. Many fine fibers from these thick bundles were distributed each lobule of the submandibular gland. A large number of single fibers terminated in the area around the striated, intercalated ducts and the acini. The densities of PGP 9.5 immunoreactive terminals were measured by a computer aided analysis system in the three areas: the striated duct, the intercalated duct, and the acini, whose densities (microm/microm2) were 0.23, 0.39 and 0.05 respectively. The relatively high density of nerve terminals in the intercalated duct suggests that the duct system probably plays an unexpectedly important role in the functional aspects.

Animals↗
PubMed2003

Fluorescence studies on nyctinasty which suggest the existence of genus-specific receptors for leaf-movement factor.

Periodic leaf-movement of legumes is called nyctinasty and has been known since the age of Alexander the Great. We found that nyctinasty is controlled by a periodic change of the internal concentration of leaf-opening and leaf-closing substances in the plant body. Now, we have developed novel fluorescent probes (1) based on the structure of cis-p-coumaroylagmatine (3), which was isolated as a leaf-opening substance of Albizzia juribrissin Durazz. Binding experiments using probe 1 showed that Albizza plants have receptors for a leaf-opening substance in their motor cells. By using probes 1 we then found that genus-specific receptors are involved in nyctinasty.

Biological Assay↗
PubMed2003

Preparation of poly(lactic acid) composites containing calcium carbonate (vaterite).

A new type of ceramic-polymer biomaterial having excellent apatite-forming ability in simulated body fluid was prepared by hot-pressing a mixture of poly(-L-lactic acid) (PLA) and calcium carbonate (vaterite). After PLA dissolved in methylene chloride was mixed with calcium carbonate consisting of vaterite, the mixture was dried completely and subsequently hot-pressed uniaxially under a pressure of 40 MPa at 180 degrees C. When 30 wt% vaterite was introduced, the modulus of elasticity was effectively improved by 3.5-6 GPa, which was about twice higher than the modulus of PLA. The composite showed no brittle fracture behavior and a comparably high bending strength of approximately 50 MPa. The composite containing 30 wt% vaterite formed a 5-15-microm-thick bonelike apatite layer on its surface after soaking in SBF at 37 degrees C even for 1-3d.

Apatites↗
PubMed2003

Thrombospondin-1 promotes fibroblast-mediated collagen gel contraction caused by activation of latent transforming growth factor beta-1.

BACKGROUND: Grafting of cultured epithelium has become a useful technique for the treatment of epithelial defects, since grafted epithelial cells secrete factors promoting wound healing. We identified one such factor produced by cultured oral epithelial cells as thrombospondin-1 (TSP-1). Recently, TSP-1 was reported to act as an activator of transforming growth factor-beta1 (TGF-beta1). OBJECTIVE: The role of TSP-1 in wound healing and its mechanism were investigated in vitro and in vivo. METHODS: The cultured oral epithelial cell-conditioned medium was harvested and applied to Heparin-Sepharose affinity chromatography. Proteins were analyzed by N-Terminal sequencer. TSP-1 and the other factors were applied to fibroblasts-mediated collagen gel contraction assay. The amount of TGF-beta1 (latent TGF-beta1 (LTGF) and active TGF-beta1) in collagen gels was quantified by ELISA and Western blotting analysis. Collagen sponges were soaked with TSP-1 and implanted subcutaneously into rats. RESULTS: A 38 kDa protein secreted from cultured oral epithelial cells was found to be human TSP-1. TSP-1 promoted collagen gel contraction activity, and anti-human TSP-1 and TGF-beta1 antibody inhibited the activity. The diameters of the gels treated with LTGF and TSP-1 were reduced to a greater extent than those of gels treated with either factor alone. Although there were no significant differences in the amounts of total TGF-beta1, which include LTGF, the amount of 25 kDa TGF-beta1 was 3.30-fold greater in TSP-1-treated samples than controls. In vivo, 7 days after implantation, increased numbers of fibroblasts were observed in the sponges treated with TSP-1. CONCLUSION: These findings suggested that TSP-1 causes collagen gel contraction by activation of LTGF. TSP-1 is expected to be especially suitable for regulating wound healing.

Adolescent↗
PubMed2003

Bone regeneration following injection of mesenchymal stem cells and fibrin glue with a biodegradable scaffold.

AIM: The purpose of this study was to determine whether a combination of fibrin glue, beta-tricalcium phosphate as a biodegradable (beta-TCP) and mesenchymal stem cells would provide three-dimensional templates for bone growth resulting in new bone formation at heterotopic sites in the rat with plasticity. MATERIAL AND METHODS: Growing stem cells and developing matrices, explanted from the rat femur, were fragmented and mixed with fibrin glue in a syringe. The cells/beta-TCP fibrin glue admixtures were injected into the subcutaneous space on the dorsum of the rat. RESULTS: Eight weeks after implantation, gross morphology revealed a pearly opalescence and firm consistency. Histological inspections showed newly formed bone structures in all admixtures, but none in the control groups when only fibrin glue and beta-TCP were injected. Osteopontin, a protein important in bone development, was identified by using antibodies in all cells/beta-TCP fibrin glue admixtures. CONCLUSION: Mesenchymal stem cells/beta-TCP fibrin glue admixtures can result in successful bone formation. This technique holds the promise of a minimally invasive means of generating autogenous bone to correct or reconstruct bony defects.

Animals↗
PubMed2003

Nerve terminals extend into the temporomandibular joint of adjuvant arthritic rats.

The innervation of the temporomandibular joint (TMJ) has attracted particular interest because of the close association with complex mandibular movement. Although the pathological changes of disk innervation may have a crucial role in the development of TMJ pain, the innervation of the TMJ disk by experimentally induced arthritis has rarely been examined in detail. Arthritic rats were induced by injection with 0.1ml solution of Complete Freund's adjuvant (CFA). We investigated three-dimensional distribution of nerve fibers in the TMJ disk using immunohistochemistry for protein gene product-9.5 (PGP-9.5) and calcitonin gene-related peptide (CGRP) in naive and arthritic rats. To clarify the possible role of nerve growth factor (NGF) and its receptor on changes in peripheral innervation of the TMJ, the expressions of trkA and p75 receptor in trigeminal ganglia were examined. Although PGP-9.5 and CGRP immunoreactive (ir) fibers were seen in the peripheral part of the TMJ disk, they were not seen in its central part. The total length and the length density of PGP-9.5 ir and CGRP ir nerve fibers increased in arthritic rats. The innervation area of fibers proliferating in the rostro-medial part merged with that of fibers in the rostro-lateral part in the arthritic rats. In addition, the ratio of trkA- and p75-positive small- and medium-sized cells increased in trigeminal ganglia. It is assumed that increasing innervation of the TMJ disk may be important for the pathophysiology of TMJ pain. NGF and its receptors are likely involved in pathological changes of the TMJ disk.

Animals↗