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Gamagōri, Japan

Nadzir M.M.,Osaka University | Kino-oka M.,Osaka University | Maruyama N.,Osaka University | Sato Y.,Osaka University | And 3 more authors.
Journal of Bioscience and Bioengineering | Year: 2011

A high density collagen type I coated substrate (CL substrate) was used to evaluate the chondrocyte phenotypes in passaged cultures. With increasing age of cell population (population doubling (PD) = 0-14.5), the frequency of non-dividing spindle shaped cells without ALP activity increased, accompanied with an increase in gene expression of collagen type I, meaning the senescence of dedifferentiated cells. At the middle age of cell population (PD=5.1 and 6.6), the high frequency of polygonal shaped cells with ALP activity existed on the CL substrate together with up-regulated expressions of collagen types II and X, indicating the terminal differentiation of chondrocytes. When the chondrocytes passaged up to the middle age were embedded in collagen gel, the high frequency of single hypertrophic cells with collagen type II formation was recognized, which supports the thought that the high gene expression of collagen type II was attributed to terminal differentiation rather than redifferentiation. These results show that the CL substrate can draw out the potential of terminal differentiation in chondrocytes, which is unattainable by a polystyrene surface, and that the CL substrate can be a tool to evaluate cell quality in three-dimensional culture with the collagen gel. © 2011 The Society for Biotechnology, Japan. Source

Kino-oka M.,Osaka University | Kagita S.,Osaka University | Nadzir M.M.,Osaka University | Inoue H.,Osaka University | And 2 more authors.
Journal of Bioscience and Bioengineering | Year: 2010

In static culture of rabbit chondrocytes in collagen gel, the direct measurement of dissolved oxygen (DO) concentration revealed that the DO level at the top surface of gel decreased due to an increase in overall cell density with elapsed time. The local cell density at the top surface on day 21 was 5.7×107 cells/cm3, being 11 times that at the bottom of gel. This heterogeneity of cell distribution in the gel was considered to occur by limitation of oxygen supply into a deeper part of the gel. In shaking culture using a dish with gas-permeable film, the DO level was enhanced inside the gel and the overall cell density in the gel was achieved to be 2.9 times that in the static culture. © 2010 The Society for Biotechnology, Japan. Source

Kojima H.,Japan National Institute of Health Sciences | Katoh M.,Japan Tissue Engineering Co | Shinoda S.,Drug Safety Testing Center Co. | Hagiwara S.,Drug Safety Testing Center Co. | And 6 more authors.
Journal of Applied Toxicology | Year: 2014

Three validation studies were conducted by the Japanese Society for Alternatives to Animal Experiments in order to assess the performance of a skin irritation assay using reconstructed human epidermis (RhE) LabCyte EPI-MODEL24 (LabCyte EPI-MODEL24 SIT) developed by the Japan Tissue Engineering Co., Ltd. (J-TEC), and the results of these studies were submitted to the Organisation for Economic Co-operation and Development (OECD) for the creation of a Test Guideline (TG). In the summary review report from the OECD, the peer review panel indicated the need to resolve an issue regarding the misclassification of 1-bromohexane. To this end, a rinsing operation intended to remove exposed chemicals was reviewed and the standard operating procedure (SOP) revised by J-TEC. Thereafter, in order to confirm general versatility of the revised SOP, a new validation management team was organized by the Japanese Center for the Validation of Alternative Methods (JaCVAM) to undertake a catch-up validation study that would compare the revised assay with similar in vitro skin irritation assays, per OECD TG No. 439 (2010). The catch-up validation and supplementary studies for LabCyte EPI-MODEL24 SIT using the revised SOPs were conducted at three laboratories. These results showed that the revised SOP of LabCyte EPI-MODEL24 SIT conformed more accurately to the classifications for skin irritation under the United Nations Globally Harmonised System of Classification and Labelling of Chemicals (UN GHS), thereby highlighting the importance of an optimized rinsing operation for the removal of exposed chemicals in obtaining consistent results from in vitro skin irritation assays. © 2013 John Wiley & Sons, Ltd. Source

Nadzir M.M.,Osaka University | Kino-oka M.,Osaka University | Sugawara K.,Japan Tissue Engineering Co | Taya M.,Osaka University
Biotechnology Letters | Year: 2013

The effect of insulin-like growth factor-1 (IGF-1) on the behavior of rabbit chondrocytes in cultured collagen (CL) gels initially seeded with 2 × 105 cells/ml was examined. On day 5, the frequency of migrating cells cultured in presence of 100 ng IGF-1/ml was 0.04, which was 54 % of the frequency in IGF-1-free culture. The presence of IGF-1 caused an increase in the frequency of dividing cells from 0.09 to 0.13. These results suggest that IGF-1 suppressed the migration of chondrocytes in the CL gels while stimulating cell division in the initial culture phase. The proteolytic migration of cells was thought to be suppressed by the down-regulation of membrane type 1 matrix metalloproteinase by IGF-1. This contributed to the formation of aggregates with spherical-shaped cells that produced collagen type II. © 2012 Springer Science+Business Media Dordrecht. Source

Japan Tissue Engineering Co. and Fujifilm Co. | Date: 2015-06-26

Artificial dermis for transplantation includes a wound contact layer that includes a porous sheet consisting of a biodegradable material, the porous sheet satisfying the following Equation, Equation: X2/X10.8. In the porous sheet, when a line parallel to a wound contact face and a line perpendicular to a wound contact face of equal length are drawn, X1 represents a number of points of intersection between the line parallel to the wound contact face and pore walls; and X2 represents a number of points of intersection between the line perpendicular to the wound contact face and pore walls.

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