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Ryo Takagi

Publications and source records attributed to Ryo Takagi.

9 recordsLinked to original sources
PubMed2006

The effect of micropores in the surface of temperature-responsive culture inserts on the fabrication of transplantable canine oral mucosal epithelial cell sheets.

Primary canine oral mucosal epithelial cells were cultured on temperature-responsive dishes and cell culture inserts to fabricate transplantable epithelial cell sheets. When 3T3 feeder layers and fetal bovine serum were eliminated from dish culture, the harvested cell sheets became significantly more fragile. In contrast, when epithelial cells were cultured on inserts having submicron-scale pores, cell sheet fragility was eliminated. Keratin expression profiles showed no differences among the harvested cell sheets, but the expression of p63, a putative stem/progenitor marker, was strongly dependent on the presence of 3T3 feeder layers and serum. These results suggest that the maintenance of stem/progenitor cells is influenced by the apical/basal supply of nutrients as well as culture supplements.

Animals↗
PubMed2006

Minimally invasive diagnosis of persistent sciatic artery by multidetector-row computed tomographic angiography.

Persistent sciatic artery is a rare but potentially significant vascular anomaly that is associated with a high incidence of aneurysm formation and limb-threatening ischemic complications. The diagnosis of persistent sciatic artery has usually been made by conventional angiography. We report a case of occluded and patent persistent sciatic arteries in which multidetector-row computed tomographic angiography allowed a definitive diagnosis of this rare vascular condition.

Aged↗
PubMed2006

Fabrication of transplantable human oral mucosal epithelial cell sheets using temperature-responsive culture inserts without feeder layer cells.

To exclude bacteria- or animal-derived factors from cultured fabrication of transplantable epithelial cell sheets, primary human oral mucosal epithelial cells were seeded on temperature-responsive culture inserts having submicron-scale pores. Supplying culture medium containing human autologous serum to both apical and basal sides of human epithelial cells allows these cells to grow to confluence. These proliferating cells created stratified epithelial layers even when 3T3 feeder layers and fetal bovine serum were eliminated from culture. Normal keratin expression profiles were obtained with these cells, and basal and midlayer cells expressed p63, a putative stem/progenitor marker. These results suggest that temperature-responsive culture inserts can be useful in clinical settings that require the exclusion of xenogeneic factors.

Animals↗
PubMed2006

Transplantation of an autologous mesothelial cell sheet prepared from tunica vaginalis prevents post-operative adhesions in a canine model.

Post-operative adhesions often cause severe complications such as bowel obstruction and abdominopelvic pain. Previously, we reported that transplantation of a mesothelial cell sheet is effective for preventing adhesion in rat model. We also proposed a new technique for harvesting autologous mesothelial cells from tunica vaginalis without intra-abdominal maneuvers. In this study, we examined whether an autologous mesothelial cell sheet can prevent post-operative peritoneal adhesions in a canine adhesion model. Mesothelial cells were isolated from the tunica vaginalis of male beagles. Isolated cells were cultured on fibrin gel. We named this construct the "mesothelial cell sheet." Animals underwent surgery to induce peritoneal adhesion formation and were then transplanted with the mesothelial cell sheets (sheet group, n = 4), fibrin gel (fibrin group, n = 4), or no materials (sham group, n = 4). Four weeks after the transplantation, we evaluated adhesion formation and scored adhesion levels. The abdominal wall transplanted with the mesothelial cell sheet was covered with mesothelium. The total adhesion score of the sheet group was significantly lower than that of the fibrin group and the sham group. These results indicated that transplantation of an autologous mesothelial cell sheet is effective for preventing post-operative adhesion formation in the canine adhesion model. Our mesothelial cell sheet has the potential to be a powerful adhesion prophylactic material in surgery.

Abdominal Wall↗
PubMed2005

Analysis of allelic imbalances at multiple cancer-related chromosomal loci and microsatellite instability within the same tumor using a single tumor gland from colorectal carcinomas.

Genetic changes related to colorectal carcinomas are accumulated in individual tumor glands during disease progression. Microsatellite allelic analysis of individual tumor glands from 30 colorectal carcinomas using a polymerase chain reaction (PCR) assay coupled with crypt isolation was used to detect intratumoral genetic heterogeneity, the sequence of allelic imbalances (AIs) and the microsatellite instability status of single tumor glands during neoplastic progression. In addition, the CpG islands methylated phenotype (CIMP) status was examined using a methylation-specific PCR method. The specimens were divided into 2 groups: a pooled gland sample, which was composed of more than 50 tumor glands, and a single tumor gland sample. The latter consisted of 10 single tumor glands, which were obtained from the same tumor separately. Most colorectal carcinomas (27 of 30 tumors) examined were heterogeneous for at least one genetic alteration, with from 2 to 7 genotypically different subclones detected per tumor. In 12 of the 27 heterogeneous tumors, it was possible to define the order of genetic alterations during the tumor progression. By analyzing multiple single tumor glands within the same tumor, we found that various subclonal expansions were seen within the same tumors. Finally, the AI pattern of single tumor glands was not correlated with CIMP status. Most carcinomas appeared to have a heterogeneous composition. This may have resulted from the successful progression of one clone that had different AIs in many chromosomal regions. This suggests that knowledge of the different genotypes of multiple single tumor glands may help clarify the process of tumor progression.

Adult↗
PubMed2005

Effect of YM529 on a model of mandibular invasion by oral squamous cell carcinoma in mice.

PURPOSE: This study examined the mechanisms of osteoclast-mediated bone invasion in a model of oral squamous cell carcinoma (OSCC). C3H/HeN mice were inoculated with SCC VII cells into the masseter region to establish an animal model of mandibular invasion by OSCC. EXPERIMENTAL DESIGN: The mice were divided into three groups: a control group, given daily s.c. injections of saline; group 1, given 2 microg per mouse per day of the bisphosphonate YM529; and group 2, given 10 microg per mouse per day of YM529. After 3 weeks of treatment, the lesions were studied by micro-computed tomography. After tartrate-resistant acid phosphatase (TRAP) staining, the osteoclasts were easily identified, and the percentages of the area occupied by osteoclasts were calculated by computer for each sample. The tumors were analyzed by RT-PCR to determine the mRNA expression of interleukin-6 (IL-6), parathyroid hormone-related protein (PTHrP), tumor necrosis factor-alpha (TNF-alpha), receptor activator of nuclear factor-kappaB (RANK), RANK ligand (RANKL), and osteoprotegerin. RESULTS: SCC VII cells rapidly multiplied in the masseter muscle of the mice. Bone invasion was evident only in the control group on micro-computed tomography. On TRAP-stained slices, the percentages of osteoclasts in groups 1 and 2 were significantly lower than that in the control group. The mRNA expressions of IL-6, PTHrP, THF-alpha, and RANK decreased as the concentration of YM529 increased. CONCLUSIONS: We conclude that various cancer-derived cytokines play important roles in the invasion of bone by OSCC. YM529, a third-generation bisphosphonate, can suppress osteoclast-mediated bone invasion by OSCC. The mechanism of this effect might involve inhibition of cytokines such as IL-6, PTHrP, TNF-alpha, and RANK by YM529.

Animals↗