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Nagata S.,Nagata Microtia and Reconstructive Plastic Surgery Clinic
Japanese Journal of Plastic Surgery | Year: 2011

The number of cases of secondary auricular reconstruction for unfavorable primary auricular reconstruction according to conventional methods has been increasing in the past few years. Secondary auricular reconstruction is needed due to incorrect anatomical location, postoperative hair growth, contracture of full-thickness skin (FTS) grafts utilized to cover the insufficient skin surface area of the conchal vault and for ear elevation, both resulting in an increase of tension, vascular compromise, etc. All these factors are capable of causing postoperative complications such as necrosis, resorption (deformation) and/or protrusion of the cartilage framework. During the first stage operation, the scar tissue and mismatched colored grafted skin are excised and the framework is removed. The subcutaneous pedicle flap is constructed in the posterior surface of the lobule and mastoid surface, and passed to the anterior surface of the 3-dimensional costal cartilage frame (3-D frame) to line the incisura intertragica and cavum concha. The newly fabricated 3-D frame is fixed to its proper anatomical location, covered with the temporoparietal fascia flap (TPF) followed by ultra-delicate split-thickness scalp skin (UDSTS). In the second stage operation, a cartilage block is fabricated for auricular projection and covered with the deep temporal fascia (DTF) followed by UDSTS cover. Elevation of the reconstructed auricle with the skin graft only must be absolutely avoided since it will lead to postoperative complications and/or problems in long-term follow-ups and the results will always be a flat and floppy reconstructed auricle. The tissue expander method must also be avoided, for the same reasons. The scientific and systematic auricular reconstruction method for secondary auricular reconstruction for unfavorable primary results with conventional methods is discussed in detail. What must be avoided?

Ko E.C.,University of Tokyo | Fujihara Y.,University of Tokyo | Ogasawara T.,University of Tokyo | Asawa Y.,University of Tokyo | And 4 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2011

Three-dimensional culture of the tissue-engineered cartilage constructs may increase the matrix production, but central necrosis must occur if the construct becomes large. To increase the cell viability in the middle part of constructs and to enhance the in vivo cartilage regeneration, we attempted to administer the insulin into the scaffold. Insulin is known to strongly enhance the matrix production in the chondrocytes. The pellets of human auricular chondrocytes with atelocollagen hydrogel were 3D-cultured in the medium. The comparison among three groups (insulin mixed in the atelocollagen, insulin added to the medium, and control group, i.e.; insulin in neither atelocollagen nor medium) revealed that both insulin mixed in the atelocollagen and that in the medium could effectively promoted the cell viability and matrix synthesis of the chondrocytes. The daily assay also showed the gradual release of insulin from the atelocollagen hydrogel, suggesting that this material may work as a control release of insulin. We actually transplanted the poly-L-lactide porous scaffolds carrying the chondrocytes and the atelocollagen mixed with or without insulin, into the nude mice, showing that glycosaminoglycan accumulation was evident in the group with insulin although less without insulin. We thus showed the possibility to enhance the in vivo cartilage regeneration, when administered insulin into the atelocollagen hydrogel. © 2011 Wiley Periodicals, Inc.

Tanaka Y.,University of Tokyo | Saijo Y.,Tohoku University | Fujihara Y.,University of Tokyo | Yamaoka H.,University of Tokyo | And 6 more authors.
Journal of Bioscience and Bioengineering | Year: 2012

The tissue-engineered cartilages after implantation were nonuniform tissues which were mingling with biodegradable polymers, regeneration cartilage and others. It is a hard task to evaluate the biodegradation of polymers or the maturation of regenerated tissues in the transplants by the conventional examination. Otherwise, scanning acoustic microscopy (SAM) system specially developed to measure the tissue acoustic properties at a microscopic level. In this study, we examined acoustic properties of the tissue-engineered cartilage using SAM, and discuss the usefulness of this devise in the field of tissue engineering. We administered chondrocytes/atelocollagen mixture into the scaffolds of various polymers, and transplanted the constructs in the subcutaneous areas of nude mice for 2. months. We harvested them and examined the sound speed and the attenuation in the section of each construct by the SAM. As the results, images mapping the sound speed exhibited homogenous patterns mainly colored in blue, in all the tissue-engineered cartilage constructs. Contrarily, the images of the attenuation by SAM showed the variation of color ranged between blue and red. The low attenuation area colored in red, which meant hard materials, were corresponding to the polymer remnant in the toluidine blue images. The localizations of blue were almost similar with the metachromatic areas in the histology. In conclusion, the SAM is regarded as a useful tool to provide the information on acoustic properties and their localizations in the transplants that consist of heterogeneous tissues with various components. © 2011 The Society for Biotechnology, Japan.

Iwata K.,University of Tokyo | Asawa Y.,University of Tokyo | Fujihara Y.,University of Tokyo | Tanaka Y.,University of Tokyo | And 5 more authors.
Current Aging Science | Year: 2010

In cartilage regenerative medicine, which is highly expected in the face of our aging society, insulin is the potent factor for culture media. To secure the safety of culture media, we attempted to use medical insulin formulations, and compared their effects on human articular or auricular chondrocytes between regular human insulin (R) and neutral protamine hagedorn insulin (N). In monolayer culture with the media containing either R or N, the cell growth reached approximately 15-fold-increase in 6 days, which showed no significant difference between them. These cells showed the equivalent ability to produce cartilage matrices, both in vitro and in vivo. Also, in the 3D culture of the dedifferentiated chondrocytes' either R or N increased gene expression of type II collagen at 3-4 folds in the combination with other growth factors, compared with basal medium, while insulin could similarly enhance both the redifferentiation and cartilage maturation. The in vitro half-life of each insulin in the presence of chondrocytes neither decreased within 3 days, suggesting little degradation in the culture media, unlike in the body. Although both R and N showed similar biological effects on cultured chondrocytes, we may choose the R for clinical practice because of its pure composition. © 2010 Bentham Science Publishers Ltd.

Tanaka Y.,University of Tokyo | Yamaoka H.,University of Tokyo | Nishizawa S.,University of Tokyo | Nagata S.,Nagata Microtia and Reconstructive Plastic Surgery Clinic | And 5 more authors.
Biomaterials | Year: 2010

To broaden the clinical application of cartilage regenerative medicine, we should develop an implant-type tissue-engineered cartilage with firmness and 3-D structure. For that, we attempted to use a porous biodegradable polymer scaffold in the combination with atelocollagen hydrogel, and optimized the structure and composition of porous scaffold. We administered chondrocytes/atelocollagen mixture into the scaffolds with various kinds of porosities (80-95%) and pore sizes (0.3-2.0 mm), consisting of PLLA or related polymers (PDLA, PLA/CL and PLGA), and transplanted the constructs in the subcutaneous areas of nude mice. The constructs using scaffolds of excessively large pore sizes (>1 mm) broke out on the skin and impaired the host tissue. The scaffold with the porosity of 95% and pore size of 0.3 mm could effectively retain the cells/gel mixture and indicated a fair cartilage regeneration. Regarding the composition, the tissue-engineered cartilage was superior in PLGA and PLLA to that in PLA/CA and PDLA. The latter two showed the dense accumulation of macrophages, which may deteriorate the cartilage regeneration. Although PLGA or PLLA has been currently recommended for the scaffold of cartilage, the polymer for which biodegradation was exactly synchronized to the cartilage regeneration would improve the quality of the tissue-engineered cartilage. © 2010 Elsevier Ltd.

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