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The purpose of this research is to verify that the proposed method, which generates vibro-stimuli according to the distance variation, has a capability of supporting depth edge detection for aperture localization. We have proposed a method to support the visually impaired understanding their surrounding environment via modality conversion from distance variation to haptic vibration information, and have developed the wearable device to provide the user with vibro-stimuli generated from visual variation inspired by optical flow characteristics. The characteristic of this vibration stimulus is that the user feels a strong vibration when the distance difference per unit time is large. It is inferred that this feature is effective in perceiving the boundary of obstacles, i.e., depth edge, which may contribute to the user's aperture localization. To verify the effectiveness of the proposed method, an aperture localization experiment was conducted to compare it with the ETAslike conventional method by changing the number of vibration motors and the method of vibration stimuli. We asked six blindfolded subjects to guess the location of the aperture. The experimental results showed that the proposed method achieved using a single motor a 98.3% correct rate. The contributions of this research are to propose the way of vibrostimuli based on distance variation for aperture localization, which is one of the important environmental elements, and to validate its effectiveness.

The purpose of this research is to propose the method providing the visually impaired users with environment understanding via modality conversion from visual distance to haptic vibration information. According to studies on ecological perception, optical flow, which represents dynamical visual variation, plays significant roles in environment understanding for human. We have developed a head-mounted wearable device equipped with a 2-dimensional distance sensor and five vibro-motors arranged around the head. The vibration magnitude of vibro-motors is defined as not static distance to the obstacle but dynamic distance variation caused from the user movement. The vibro-stimuli are generated based on the optical flow characteristics. Thus, if the user moves to the obstacle dynamically, the user feels stronger vibration; in contrast, if the user pauses, the user feels no vibration since the distance to obstacles keeps constant. To evaluate basic performance of the proposed method, we asked five blindfolded subjects to walk toward the wall 50 times each. First 10 trials performed by each subject are considered as practice phase; hence, the remaining 40 trials are evaluated. In total 200 trials, the 97.5% of trials are considered as success ones; the almost subjects were able to perceive the wall existence and stopped without the collision with the wall. The experiment demonstrated the basic validity of our proposed method. The main contribution of this paper is utilizing dynamic distance variation to determine vibration magnitude and providing the user with vibro-stimuli simulated by optical flow to support the user’s localization in the environment.

An Internet-based survey was administered in Japan to compare mental health of and stigma toward unemployed individuals, workers with regular employment, and workers with irregular employment. Unemployed individuals showed higher scores for both anxiety/depression and disturbance of activities, as well as faced more stigma than did employed individuals. In addition, the factor structure of stigma that unemployed individuals have toward the unemployed was the same as that previously found for university students and employed individuals. Financial strain and stigma were the factors with the greatest influence on the mental health of unemployed individuals.

In order to prevent postoperative adhesion and the related complications, a thermally crosslinked gelatin (TCG) film was developed and the basic biological properties were examined, paying special attention to the relationship between these properties and the extent of crosslinking of the film. The gelatin films crosslinked thermally for five different time periods (0, 1, 3, 8, and 14 hours) were developed and the following tests were performed. Regarding the material characterization of the films, the water content, the water solubility, and the enzymatic degradation for collagenase were found to be closely related to the duration of thermal crosslinking. In an in vitro study conducted to examine the cell growth of fibroblasts cultured on the films, the degree of cell growth, except no crosslinked film, was less than that observed in the control group, thus suggesting that such effects of the films on fibroblast cell growth may be related with their anti-adhesive effects. In in vivo tests, the films crosslinked for longer time periods (3, 8, and 14 hours) were retained for longer after being implanted into the abdominal cavity in rats and showed a significant anti-adhesive effect in the rat cecum adhesion models, indicating that the biodegradability and anti-adhesive effects of the TCG films depend on the duration of thermal crosslinking. In order to develop useful and effective anti-adhesive gelatin film, it is very important to optimize duration of the thermal crosslinking.

ADSCs(脂肪組織由来幹細胞)は再生医療において有用な細胞源であり、臨床でも応用されている。しかしながら三次元的マトリックスの足場なしでは複雑な構造の組織再生は難しく、ADSCsを用いてこのような組織再生を行なう際には足場が必要である。従来、人工足場としてはPGA不織布が汎用されているが、PGAは疎水性であるためにADSCsの接着性と増殖性が低いと考えられる。細胞接着性と増殖性を改善するために、我々はコラーゲンコーティングPGA不織布を開発した。ラットの鼠蹊部より採取した脂肪組織から得た細胞の内でフローサイトメトリーによりCD29、90が陽性かつCD 11b、45が陰性と特徴つけられる細胞群をADSCsとして実験を行った。In Vitroの細胞増殖試験で、コラーゲンコーティングPGA不織布上では、それに対応するコラーゲン非コーティングPGA不織布上よりも細胞の接着・増殖が良好であった。この結果は、コラーゲンコーティングによりPGA不織布繊維表面が親水性になり、ADSCsの接着・増殖に有利な環境に変化したためと考えられる。, Adipose-derived stem cells (ADSCs) have attracted attention as a useful cell source for tissue engineering, even in the clinical setting. However, it is difficult to regenerate tissues with complex structures in the absence of a three-dimensional matrix such as an artificial scaffold. Namely, scaffolds are required to allow implanted ADSCs to regenerate tissues with three-dimensional structures. Although non-woven PGA (poly (glycolic acid)) fabric has been used widely as an artificial scaffold, ADSCs poorly adhere to and grow on PGA fabric due to its hydrophobicity. To improve cell adhesion and growth on PGA fibers, we devised a PGA fabric coated with collagen. We isolated ADSCs from the inguinal adipose tissue of a rat and characterized the cells using flow cytometry with both CD29- and CD90-positive markers and CD11b- and CD45-negative markers. Our cell growth examination revealed that ADSC growth was improved on all of the collagen-coated fabrics compared with that observed on the corresponding non-coated fabrics. This may be because ADSCs are able to adhere and grow more readily on the hydrophilic surface of collagen-coated PGA fabrics.

腹部外科手術後の癒着障害を防ぐため、我々は新規癒着防止材として熱架橋ゼラチンフィルムを開発し、これまでに動物実験においてその優れた癒着防止効果と良好な腹膜再生を報告した。しかしながら、ゼラチンは哺乳類において最も豊富な細胞外マトリックスタンパクであるコラーゲンの変性産物であり、またコラーゲンは再生医学の領域において有用な足場材料でもあることから、ゼラチンフィルムを消化器癌症例の手術において使用した場合、癌細胞にとっても好都合な足場となり、その腹膜播種性転移を助長する可能性も考えられる。そこで我々はこのことを明らかにするため、ゼラチンフィルムの癌細胞の増殖への影響をin vitro実験により検討を行った。細胞は接着性のヒト大腸癌細胞HT29およびヒト胃癌細胞MKN74と、半浮遊性のヒト胃癌細胞KATO-IIIを用いた。ゼラチンフィルム上で各癌細胞の培養を行い、細胞播種後1,3,5,7日目に細胞数の測定を行った。その結果、接着性のHT29およびMKN74において、ゼラチンフィルム上で経時的に細胞が増殖していたが、ゼラチンフィルムを置かなかったコントロール群を有意に下回った。一方、半浮遊性癌細胞KATO-IIIにおいては、HT29およびMKN74細胞に比べ、ゼラチンフィルム上でより増殖していたが、やはりコントロール群を下回っていた。これらの癌細胞のin vitro実験の結果からは、熱架橋ゼラチンフィルムは癒着防止材として癌症例に用いた場合でも、癌細胞の増殖にとって好都合な足場とはなりにくく、その腹膜播種性転移を助長することは少ないと考えられた。しかしながら、今後さらにin vivo実験を行ってゆく必要があると思われる。, To prevent adhesion formation after abdominal surgery, we newly developed a thermally cross-linked gelatin film and previously reported its superior anti-adhesive effects with excellent peritoneal regeneration. However, since the gelatin film is made from a degenerated product of collagen which is the most abundant extracellular matrix protein in mammals and has been used as a scaffold in the field of regeneration medicine, it may act as a scaffold convenient for cancer cell growth, thereby accelerating peritoneal dissemination when used in surgery for abdominal cancers. To clarify this issue, in this study, we examined effects of the gelatin film on in vitro cancer cell growth, using the human colon cancer cell line HT29 and the human gastric cancer cell lines MKN74 and KATO-III. HT29 and MKN74 cells exhibit an adherent growth mode and Kato-III cells exhibit a semi-floating growth mode in conventional culturing. The cancer cells were cultured on the gelatin film or without the film (control), and each viable cell number was counted at 1, 3, 5 and 7 days after seeding. The growth of the HT29 and MKN74 cells was significantly less than that observed in the control group, although both cells grew on the gelatin film with time. Compared with the other two cell lines, the KATO-III cells seemed to grow on the gelatin films well. However, the cell growth was also less than that observed in the control group. The results of this in vitro study suggest that gelatin film may not act as a scaffold convenient for cancer cell growth or accelerate peritoneal dissemination, although further in vivo studies are needed.

腹部外科手術において安全に使用でき、優れた癒着防止効果を持つ癒着防止材を作るために、我々は、新規熱架橋ゼラチンフィルムを作製し、これまでに犬の実験で、その優れた癒着防止効果と、腸管吻合部においても安全に使用できることを報告してきた。今回我々は、ゼラチンフィルムの手術使用時の操作性を評価するため、その物理学的特性について、セルロースフィルムと比較検討を行った。単純引張試験および剪断試験において、熱架橋ゼラチンフィルムとセルロースフィルムの、それぞれの最大荷重、弾性率、破断ひずみを評価した。さらに、ゼラチンフィルムの熱架橋時間とこれらの物理的特性との関係についても評価を行った。その結果、単純引張および剪断の両試験共に、各ゼラチンフィルムの最大荷重値が、セルロースフィルムより、有意に上回った。また、各ゼラチンフィルムの破断ひずみ値も、セルロースフィルムより有意に上回った。しかしながら、弾性率については、両試験共に、各ゼラチンフィルムとセルロースフィルムの間で有意な差を認めなかった。一方、ゼラチンフィルムにおいて、熱架橋時間による物理的特性の違いは認められなかった。これらの結果から、熱架橋ゼラチンフィルムは、その熱架橋時間に関係なく、セプラフィルムに比べ、より物理学的強度を持つ材料であり、且つ伸びやすい材料であると考えられた。従って、熱架橋ゼラチンフィルムはセプラフィルムよりも手術使用時において、より優れた操作性を持ち合わせていると考えられた。, To generate a more effective and safer anti-adhesive material, we developed a new thermally cross-linked gelatin film. We previously reported that this film had superior anti-adhesive effects compared to cellulose film and could be used safely on the intestinal anastomosis in canine models. To evaluate the handling of the gelatin film during surgery, we investigated the physical properties of the gelatin film and compared it with cellulose film. We performed tensile and shear tests to evaluate the maximum loads, the elastic modulus and the fracture strains of the gelatin film, paying special attention to the relationship between the time required for the thermal cross-linking and those physical properties. The maximum tensile and shear loads of each thermally cross-linked gelatin film were significantly higher than those of cellulose film. The fracture strains of each gelatin film were also significantly higher than those of cellulose film. However, there were no significant differences in the elastic modulus between the gelatin films and the cellulose film in terms of both the tensile and shear tests. There were no significant differences in these physical properties among the gelatin films allowed to thermally cross-link for different lengths of time. In conclusion, thermally cross-linked gelatin film has a higher physical strength and ductility than cellulose film, regardless of the time allowed for thermal cross-linking. These physical properties of the gelatin films are considered to be advantageous for their handling during surgery.

膵液漏局所化のためのポリグリコール酸不織布(PGA不織布)を開発した。膵液に対する防御壁としての肉芽組織をスムーズに密に形成する足場として、3種類の足場材料を検討した。すなわちpoly (L-lactide-ε-caprolactone)コポリマーフィルム、繊維径0.9μmのPGA不織布、繊維径20μmのPGA不織布である。ラットの膵臓表面を電気メスで焼灼する膵液漏出モデルを用いた。3種類の足場材料の各1種類の材料を膵臓の焼灼された表面を覆うように周囲組織に逢着した。術後5日間、ラットの生死を観察し、5日目に剖検して肉眼的、顕微鏡的に観察した。PGA不織布の2群では、その他の2群に比べて生存率は高く、フィルム群との間で有意差を認めた。肉眼的観察では、腹水貯留、汎発性腹膜炎や腹腔内全臓器が一塊となる腫瘤形成のような重度の病理所見がみられたが、フィルム群に対してPGA不織布の2群は有意に少なかった。顕微鏡的観察では、肉芽組織は繊維径0.9と20μmのPGA不織布の全層にわたり形成され、組織障害や炎症反応は不織布外側では内側に比べ軽度であった。このようにPGA不織布では膵液漏の局所化が可能であった。対して補強なし群とフィルム群では、組織障害や炎症反応は膵臓から離れた広範囲に及んでいた。フィルム群では特に、フィルム外側でも炎症性単核細胞の集積がフィルムに沿い広がり、フィルム周囲では防御壁としての肉芽形成は乏しかった。このように補強なし群と比較しても、フィルム群では、膵液による組織損傷や炎症がより広範囲に及び、防御壁となる肉芽形成は悪かった。結論として、PGA不織布は膵液漏の治療の足場材料として有効と考えられた。, We developed sheets of non-woven poly (glycolic acid) PGA fabric that can act as a scaffold to form smoothly dense granulation tissue for barrier walls to localize leakage of pancreatic juice. In this study, we tested three kinds of materials: poly (L-lactide-ε-caprolactone) (copolymer) film, PGA fabric-0.9 with a mean fiber diameter of 0.9µm and PGA fabric-20 with a mean fiber diameter of 20 µm. Under general anesthesia, the pancreatic surface of in rats was cauterized with an electric scalpel. Then, the pancreas was wrapped with one of the three kinds of sheets and the sheet was fixed onto the surrounding tissues. Survival was observed for five days after surgery. The survival rates were higher in the two groups of fabric-treated rats than in the other groups, although the differences were significant only for the film-treated group. Macroscopically, severe pathologic findings such as accumulation of ascites, tumor formation in whole intraperitoneal organs and generalized peritonitis occurred at a significantly lower incidence in the two fabric-treated groups than in the film-treated group. Microscopically, granulation tissue was formed along the fabrics throughout the full thickness of the fabric scaffolds of fabric-0.9 and fabric-20. In these groups, injurious tissue changes and inflammatory reactions were reduced in the outer zone of the fabric wall compared to that observed in the inner zone. Therefore, the new PGA fabrics successfully localized pancreatic juice leakage. In contrast, in the no treatment group and the film-treated group, injurious tissue changes and severe inflammation were spread out to places distant from the cauterized pancreas. In the film-treated group in particular, the accumulation of mono nuclear inflammatory cells was spread along the film, even into the outer zone of the sheet, and granulation formation of a barrier wall was suppressed around the film. Therefore, in the film-treated group, tissue injury and inflammation caused by pancreatic juice extended more widely and granulation formation of a barrier wall was strongly suppressed, even compared with that observed in the no treatment group. In conclusion, these fabrics can be a more suitable and effective material for the treatment of leakage of pancreatic juice.

手術中の制御困難な出血は死亡率増加や医療費の高額化をもたらすため、術中止血は重要な課題である。そのため、多くの局所止血材が開発されている。このうちで、タココンブ(TC)は最も使用頻度が高く効果的な局所止血材の一つである。しかし、TCの優れた止血効果はヒト血液製剤と動物組織由来の止血成分を構成要素として使用されていることによる。これはTCの使用により感染症やアレルギー反応のリスクが高くなる問題を引き起こす。この問題を解決するために、アルカリ処理によりゼラチンのウイルスや抗原性構造部位ほぼ完全に排除されることに着目し、筆者らは構成要素としてアルカリ処理ゼラチンのみを使用しこれを凍結乾燥してゼラチンスポンジ作成し、これとゼラチン糊とを組み合わせた新規の止血材を考案した。スポンジ構造が傷口からの流出血液を速やかに吸収してゼラチンと粘性ゲルを形成し、同時に血中凝固成分が直ちに活性化され、その結果、出血部位で急速に血餅形成が促進される。更にゼラチン糊が血餅を含む粘性ゲルを出血部位に強固に糊着させる。本実験では(A)ゼラチンスポンジとゼラチン糊との組み合わせ、(B)タココンブ単独、(C)ゼラチン糊単独の3種類の止血材について、犬の脾臓表面を損傷させた実験モデルを用いて止血効果を比較した。その結果、ゼラチンスポンジとゼラチン糊の併用は、他の2つの材料に比較して有意に優れた止血効果を示した。結論として、ゼラチンスポンジとゼラチン糊の組み合わせは、その優れた止血効果に加えて、感染症やアレルギー反応のリスクが極めて低い利点を持つ、有用な局所止血材であることが明らかになった。, Hemostasis is a key issue in surgery because uncontrolled surgical bleeding is associated with increased mortality rates and higher costs. Many types of topical hemostatic materials have been developed. One of the most current and most effective materials is TachoComb (TC), which is reabsorbed well by conversion into connective tissue. However, TC's excellent hemostatic effects are brought about by the use of hemostatic components and a framework derived from human and animal tissues. This means that TC use is associated with a risk of infectious diseases and allergic reactions. To address the above-mentioned problems with the most current hemostatic material, we devised a new hemostatic material composed of a framework of a freeze-dried gelatin sponge combined with gelatin glue, thereby creating a new topical hemostatic material made of gelatin alone. The gelatin used in the material was prepared with alkali-treatment, and the immunogenicity and activity of viruses were eliminated almost completely. The framework absorbs blood flowing out from the wound immediately, activates autologous coagulation components in the absorbed blood and promotes blood coagulation at the bleeding site. The hemostatic effects of three types of hemostatic materials were compared, namely (A) the gelatin sponge combined with gelatin glue, (B) TC and (C) gelatin glue alone, using a dog's spleen with a shaved wound surface. Consequently, combined use of the gelatin sponge and gelatin glue exhibited significantly superior hemostatic effects to the other two materials. In the conclusion, the combination of a gelatin sponge sheet and gelatin glue is useful as a topical hemostatic material due to its superior hemostatic effects and extremely low risk of infectious diseases and allergic reactions.

コラーゲンやゼラチンのアルカリ抽出法は、従来の酸処理や酵素処理法に比べ幾つかの優れた利点を有する。一方で、その過程において等電点が酸性化する事が知られており、その生物学的な効果や影響については未だ十分に明らかになっていない。そこで本論文では、そのようなアルカリ処理コラーゲンやゼラチンの生物学的性質を調べるため、足場材料として用いた場合の細胞増殖に対する影響について予備的に検討を行った。さらにアルカリ処理コラーゲンやゼラチンに対する架橋修飾による影響、および反対の等電点をもつコラーゲンやゼラチンとの混合による影響等についても検討を行った。ペプシン処理コラーゲン、アルカリ処理コラーゲン、酸処理ゼラチン、アルカリ処理ゼラチンを、それぞれコーティングしたプレート上においてラット培養細胞を培養し、4日後その増殖の程度について評価を行った。結果、アルカリ処理コラーゲンやゼラチンにおいて、細胞増殖の低下が認められた。しかしながらUV架橋を行ったところ、その細胞増殖が回復することが認められた。また、ペプシン処理コラーゲンとアルカリ処理コラーゲンを混合した場合、少量を混合した場合は特に影響を認めなかったが、等量近く混合した場合においては、細胞増殖が極端に低化していた。一方酸処理ゼラチンとアルカリ処理ゼラチンを混合した場合においても、細胞増殖の低下は認められたが、その極端な低下は認められなかった。以上より、アルカリ処理コラーゲンやゼラチンを足場として用いた場合、細胞の増殖はむしろ低下していた。しかしながら、適度の架橋を加える、あるいは従来のアルカリ性の等電点を持つコラーゲンやゼラチンと適切な配合比において混合使用することにより、足場機能を損なわずに、そのアルカリ処理による利点を生かした有用な足場材料として使用できる可能性があると考えられた。, The alkaline treatment to extract collagen or gelatin has several benefits, compared with conventional acid or enzymatic treatment. However, during such alkaline processing, the isoelectric points of collagen and gelatin are shifted from alkalinity to acidity, and the biological influences have not yet been fully established. In order to clarify the biological properties of the alkali-treated collagen or gelatin, we performed a preliminary examination of the influence on the cell growth when these materials are used as scaffolds. Furthermore, we studied the effects of the alkali-treated collagen and gelatin on cell growth by UV cross-linking or by mixing them with the conventional pepsin-treated collagen or acid-treated gelatin showing the opposite isoelectric points. After four days in culture on the plates coated with pepsin-processed collagen (pep-collagen), alkali-treated collagen (alk-collagen), acid-treated gelatin (acd-gelatin) or alkali-treated gelatin (alk-gelatin), the number of rat fibroblasts was evaluated. The cell growth on the alk-collagen and gelatin decreased, in comparison with the control (non-coated). However, the cell number on the alk-collagen and -gelatin was improved when they were UV cross-linked. The cell growth was not affected when a small amount of pep- or alk-collagen was mixed with alk- or pep-collagen, respectively. However, the cell growth was decreased remarkably, when these collagens were mixed at a nearly equal ratio. The inhibition of the cell growth was also seen after mixing acd-gelatin and alk-gelatin. However, this inhibition of the cell growth was not significant. In summary, the alk-collagen and gelatin decreased the cell growth rather than control when used as scaffolds. However, by adding UV cross-linking or by mixing them with conventional collagen or gelatin at suitable compounding ratios, these materials may be therefore utilized as a more useful scaffold without spoiling their function.

To generate a more effective and safer anti-adhesive material, we have developed a new type of thermally cross-linked gelatin film. In this study, we preclinically examined the anti-adhesive efficacy of this film and evaluated the possibility applying the film safely onto fresh intestinal anastomoses, compared with hyaluronate and carboxymethyl-cellulose (HA/CMC) film. Using a canine adhesion model, the degree of adhesion for each film was evaluated by adhesion scoring systems and histological observation. Three weeks after surgery, only the gelatin film showed significantly superior anti-adhesive effects compared to the control (no treatment), in particular, exhibiting excellent re-peritonization. Next, in a canine anastomosis model, the anastomoses were wrapped directly by each film and the bursting pressures of the anastomoses were examined 3 and 7 days after surgery. The gelatin film did not significantly affect either the bursting pressures or the healing process, compared with the control. However, the HA/CMC film significantly decreased the bursting pressures measured at 3 days after surgery. In conclusion, the thermally cross-linked gelatin film had satisfactory anti-adhesive effects with excellent re-peritonization. It could be safely applied to intestinal anastomoses without decreasing the bursting pressures. The gelatin film is considered to be quite favorable as an anti-adhesive material.

目的:組織再生の足場は、直径が50～500nmである細胞外マトリックスの構造に可及的に類似することが望ましい。そこで、本実験では、直径0.7、0.9、3、7、20μmと繊維径の異なった5種類のポリグリコール酸繊維を用いて、5種類の不織布の足場を作製し、これらの足場が浸潤細胞及び肉芽組織形成に及ぼす影響を調べた。実験方法:6匹のラットの背部皮下組織に、それぞれ5つのポケットを作成し、5種類の足場を1つずつ別々のポケットに埋稙した。埋稙した足場とその周囲組織を、術後14日目に摘出し、病理組織学的に浸潤細胞及び肉芽組織形成の2つの観点から評価した。結果:繊維径0.9μmで繊維間隔10.8μmの足場と繊維径3μmで繊維間隔9.0μmの足場を用いた場合は、緻密な肉芽組織が足場の全層に渡り形成された。繊維径7μmで繊維間隔15.1μmの足場と繊維径20μmで繊維間隔31.6μmの足場を用いた場合は、疎な肉芽組織が繊維束間の空間に、やや疎な肉芽組織は、繊維束の周囲にのみ形成されていた。繊維径0.7μmで繊維間隔1.8μmの足場では、緻密な肉芽組織が足場の表面にのみ形成され、足場の内側へは細胞浸潤・肉芽組織形成は見られなかった。結論:繊維径3μm未満で繊維間隔が10μm付近の足場が、足場全層に渡り緻密な肉芽組織形成を引き起こし、組織再生の足場として最も適切であると考えられた。, The fibers of the extracellular matrix (ECM) typically have diameters ranging from 50 to 500 nm. A scaffold should mimic the structure of the ECM as much as possible. As a result, 5 different fibers with diameters of 0.7, 0.9, 3, 7 and 20 μm were made into 5 kinds of scaffolds for tissue-regeneration. The scaffolds were made of Poly(glycolic acid) (PGA) nonwoven fabrics with fiber-spacing of 1.8 to 31.6 μm. This study investigated the influence of the 5 different scaffolds on infiltrating cells and granulation-formation. Six female Wistar rats underwent surgery to create 5 “pockets" in the subcutaneous tissue of the back, and one of the 5 types of PGA scaffolds was implanted into each “pocket". These implanted PGA scaffolds and surrounding tissues were excised en block on postoperative days 14, and then the infiltrating cells and granulation-formation were assessed microscopically. In the scaffolds with a fiber-diameters of 0.9 and 3 μm and fiber-spacing of 10.8 and 9.0 μm, respectively, dense granulation tissue was formed over the full-thickness of the scaffolds. However, in the scaffolds with fiber-diameters of 7 and 20 μm and fiber-spacing of 15.1 and 31.6 μm, respectively, a relatively sparse granulation tissue was formed only around the fiber bundles and sparse granulation tissue was observed to form in the spaces between the bundles. In the scaffolds with a fiber-diameter of 0.7 and fiber-spacing of 1.8 μm, dense granulation tissue only formed in the superficial and shallow layers of the scaffolds, and no cell-infiltration was found in the central region of the thickness. These results suggest that scaffolds with fiber-diameters smaller than 3 μm and fiber-spacing approximately 10 μm are suitable for artificial scaffolds made with PGA fibers to induce the regeneration of dense granulation tissue over the full-thickness of the scaffold.

我々は腹部外科手術後の癒着障害の予防軽減を行う為、新規癒着防止膜である熱架橋ゼラチンフィルムを開発作成し、これまで犬を用いた実験にてその優れた癒着防止効果と消化管吻合部に対しても安全に使用できることを報告してきた。今回我々は、熱架橋ゼラチンフィルムの物理的・生物学的特性について基礎的解析を行い、現在臨床で汎用されている癒着防止膜であるセプラフィルム(ヒアルロン酸とメチルセルロースの合材)とそれぞれ比較することにより、その操作性や癒着防止や吻合部への影響等の機序について予備的検討を行ったので報告する。最初に本材とセルロースフィルム(セプラフィルム○R)の引張揃断応力を測定した結果、特にフィルムを90°ひねった状態で牽引した場合、乾燥状態においても湿潤状態おいても、本材はセルロースフィルムに対し有意に強度を保つ事が分かった。次に各フィルムの溶解性試験を行ったところ、本材とセルロースフィルムは類似した溶解性を持ち、約7日間かけて徐々に70-80%溶解していた。一方、各フィルム上での細胞増殖と生死判定試験を行ったところ、ゼラチンフィルム上では経時的な細胞の増殖を認めたのに対し、セルロースフィルム上においては顕著に細胞数の減少がみられ、さらに5日目にはほぼすべての細胞が死滅することが確認された。以上のことから、熱架橋ゼラチンフィルムはセルロースフィルムに比べ、物理的強度が認められ、より操作性に優れると考えられた。セルロースフィルム及びゼラチンフィルムはどちらも腹膜損傷部において癒着形成に重要な約7日間程度物理的なバリアとして存在することで癒着防止をすると考えられるが、セルロースフィルムは細胞増殖を阻害する事で創治癒にも抑制的に作用するのに対し、熱架橋ゼラチンフィルムはそれらを抑制せず、結果的により良好な創傷治癒を伴う癒着防止効果があり、また腸管吻合部においても安全に使用できると考えられた。結論として熱架橋ゼラチンフィルムは吻合部に使用しても負の影響のない優れた癒着防止材であることを報告する。, To prevent postoperative abdominal adhesion, we have developed a novel anti-adhesive material made of thermally cross-linked gelatin film. Previously, we reported that it had an excellent anti-adhesive effect and that it could be used safely for intestinal anastomosis in a canine model. This study analyzed the physical and biological properties of the thermally cross-linked gelatin film preliminarily, and investigated the handling and the mechanism of anti-adhesive effect and the influence on intestinal anastomotic sites, in comparison to a combination film composed of hyaluronic acid and carboxymethyl cellulose (cellulose film), that is commonly used in clinical situations. The tensile strength of the thermally cross-linked gelatin film was significantly higher than that of cellulose film when twisted to 90° in both wet and dry conditions. A degradation test in distilled water showed both films dissolved gradually with time and were nearly 70-80% dissolved by seven days. This suggested that these films have similar solubility. Tests of in vitro cell growth and viability on each film showed that cultured cells grew well over time on the thermally cross-linked gelatin film. On the other hand, the cell number decreased significantly on cellulose film and most of the cells died within seven days. These results suggest the thermally cross-linked gelatin film had more physical strength and better handling than cellulose film. Both thermally cross-linked gelatin film and cellulose film were thought to prevent adhesion as physical barrier during seven days after surgery, which is a significant period for adhesion formation. However the results also suggested that the cellulose film acted as anti-adhesive membrane by inhibiting cell growth and wound healing. In contrast, the thermally cross-linked gelatin film did not inhibit cell growth, and resulted in more favorable wound healing as well as anti-adhesive effects. Therefore, it could be used safely for intestinal anastomosis. In conclusion, the thermally cross-linked gelatin film is considered to be an excellent anti-adhesive material that has no negative effects on intestinal anastomosis sites.

Postoperative intra-abdominal or intrathoracic adhesions sometimes cause significant morbidity. We have designed three types of alginate-based treatments using strongly cross-linked (SL), weakly cross-linked (WL), and non-cross-linked (NL) alginate with calcium gluconate. In rat experiments, we compared the antiadhesive effects of the three types of alginate-based treatments, fibrin glue treatment (a standard treatment), and no treatment against adhesions caused by polyglycolic acid (PGA) mesh (PGA-induced adhesions). The antiadhesive materials were set on the PGA sheet fixed on the parietal peritoneum of the abdomen. Fifty-six days later, the adhesions were evaluated macroscopically by the adhesion scores and microscopically by hematoxylin-eosin staining and immunostaining. We also tested the fibroblast growth on the surface of the antiadhesive materialsin vitro. The antiadhesive effects of WL and NL were superior to the no treatment and fibrin glue treatment. A microscopic evaluation confirmed that the PGA sheet was covered by a peritoneal layer constructed of well-differentiated mesothelial cells, and the inflammation was most improved in the NL and WL. The fibroblast growth was inhibited most on the surfaces of the NL and WL. These results suggest that either the WL or NL treatments are suitable for preventing PGA-induced adhesions compared to SL or the conventional treatment.

In order to prevent postoperative adhesion and the related complications, a thermally crosslinked gelatin (TCG) film was developed and the basic biological properties were examined, paying special attention to the relationship between these properties and the extent of crosslinking of the film. The gelatin films crosslinked thermally for five different time periods (0, 1, 3, 8, and 14 hours) were developed and the following tests were performed. Regarding the material characterization of the films, the water content, the water solubility, and the enzymatic degradation for collagenase were found to be closely related to the duration of thermal crosslinking. In an in vitro study conducted to examine the cell growth of fibroblasts cultured on the films, the degree of cell growth, except no crosslinked film, was less than that observed in the control group, thus suggesting that such effects of the films on fibroblast cell growth may be related with their anti-adhesive effects. In in vivo tests, the films crosslinked for longer time periods (3, 8, and 14 hours) were retained for longer after being implanted into the abdominal cavity in rats and showed a significant anti-adhesive effect in the rat cecum adhesion models, indicating that the biodegradability and anti-adhesive effects of the TCG films depend on the duration of thermal crosslinking. In order to develop useful and effective anti-adhesive gelatin film, it is very important to optimize duration of the thermal crosslinking.

Various vascular and valvlular grafts are commonly used in the treatment of cardiovascular disease. Current prosthetic or bioprosthetic materials lack growth potential, and therefore, subsequent replacement further defeats the concept of primary repair early in pediatric cardiac patients. Tissue engineering is a new discipline that offers the potential to create replacement structures from autologous cells and biodegradable polymer scaffolds. Because tissue-engineering constructs contain living cells, they may have the potential for growth, self-repair, and self-remodeling. Cardiac valve leaflets and large conduits in the pulmonary ciruulation have been made with this tissue-engineering approach in lambs. Venous conduits were also created in dogs. Mixed cell populations of endothelial cells and fibroblasts were isolated from explanted peripheral arteries or vein. A synthetic biodegradable scaffold con-sisting of polyglactin and polyglycolic acid fibers was seeded in vitro with mixed cultured cells. After one week, these autologous cell/polymer constructs were reimplanted in animals. Each animal was then followed periodically by echocardiography and angiography. The animals were sacrificed, and the implanted tissues were examined histologically, biochemically, and biomechanically. A 4-hydroxyproline assay was performed to evaluate the collagen content. The implanted conduit diameters increased as the animals grew during the study period. Histologically, the biodegradable polymer scaffold was completely degraded. Collagen analysis of the constructs showed the development of an extracellular matrix. Immunohistochemical staining demonstrated elastin fiber in the matrix and factor VIII on the inner surface of the conduits. In conclusion, a tissue-engineering approach to constructing cardiovascular structures is feasible using cells of either arterial or venous origin. In these tissue-engineered autografts, transplanted autologous cells generated the proper matrix over the polymer scaffold under physiologic conditions.

To overcome the problems associated with sheet- or film-type anti-adhesive materials, we developed a new type of anti-adhesive material, gelatin flakes. We made two types of gelatin flakes with or without thermal cross-linking, and preliminarily examined their basic properties and the anti-adhesive efficacy using a rodent adhesion model. Both types of the gelatin flakes rapidly turned into gel and tightly attached the injured surfaces, absorbing the moisture and blood, when applied onto the abraded sites of rats. In addition, these flakes could be sprayed into the desired area by compressed air through a device with a long, thin tube, which could be used in laparoscopic surgery. The anti-adhesive effects of both types of gelatin flakes were similar, and both types were significantly superior compared to the non-treated group. Although further investigations are necessary, the gelatin flakes have unique and useful properties and satisfactory anti-adhesive effects, which indicate that they may be applicable in laparoscopic surgery.

This study investigated the images that people have of the unemployed. In study 1, general images of the unemployed were ascertained through qualitative and quantitative research. Various images, both positive and negative, were found for the unemployed in general. In study 2, a scale to measure the level of stigma associated with the unemployed was created based on the images from study 1. The results yielded four subscales for stigma associated with the unemployed. University students seemed to show more stigma for the unemployed on some sub-scales than typical adults did. Working experiences, such as an internship or a part-time job during student life, would promote the reduction of the stigma associated with the unemployed.

The purpose of this study was to investigate the relation between intention to serve the same company for long years and job satisfaction in Japanese workers. Four hundred eighteen Japanese workers completed a questionnaire to assess intention to serve for long years and job satisfaction. Job satisfaction was measured by two scales. One scale was consisted of the items which were deviced in the preliminary study concerning satisfaction with the company, and the other was consisted of the items based on the Minnesota Satisfaction Questionnaire. A factor analysis on the former scale yielded four factors: fosterage by company, order in company, company's name recognition, and expansibility of company. A factor analysis on the latter yielded four factors: contribution and activity, recognition and benefits, supervision, and discretion on job. The multiple regression analysis showed that "expansibility of company" was the most important predictor of intention to serve for long years.

To determine the potential development in vivo of tissue-engineered auricular cartilage, chondrocytes from articular cartilage of bovine forelimb joints were seeded on poly(L-lactic acid-epsilon-caprolactone) copolymer scaffolds molded into the shape of a human ear. Copolymer scaffolds alone in the same shape were studied for comparison. Chondrocyte-seeded copolymer constructs and scaffolds alone were each implanted in dorsal skin flaps of athymic mice for up to 40 weeks. Retrieved specimens were examined by histological and molecular techniques. After 10 weeks of implantation, cell-seeded constructs developed cartilage as assessed by toluidine blue and safranin-O red staining; a vascular, perichondrium-like capsule enveloped these constructs; and tissue formation resembled the auricular shape molded originally. Cartilage matrix formation increased, the capsule persisted, and initial auricular configuration was maintained through implantation for 40 weeks. The presence of cartilage production was correlated with RT-PCR analysis, which showed expression of bovine-specific type II collagen and aggrecan mRNA in cell-seeded specimens at 20 and 40 weeks. Copolymer scaffolds monitored only for 40 weeks failed to develop cartilage or a defined capsule and expressed no mRNA. Extensive vascularization led to scaffold erosion, decrease in original size, and loss of contour and shape. These results demonstrate that poly(L-lactic acid-epsilon-caprolactone) copolymer seeded with articular chondrocytes supports development and maintenance of cartilage in a human ear shape over periods to 40 weeks in this implantation model.

Tissue-engineered vascular autografts (TEVAs) were made by seeding 4-6 x 10(6) of mixed cells obtained from femoral veins of mongrel dogs onto tube-shaped biodegradable polymer scaffolds composed of a polyglycolid acid (PGA) nonwoven fabric sheet and a copolymer of L-lactide and caprolactone (n = 4). After 7 days, the inferior vena cavas (IVCs) of the same dogs were replaced with TEVAs. After 3, 4, 5, and 6 months, angiographies were performed, and the dogs were sacrificed. The implanted TEVAs were examined both grossly and immunohistologically. The implanted TEVAs showed no evidence of stenosis or dilatation. No thrombus was found inside the TEVAs, even without any anticoagulation therapy. Remnants of the polymer scaffolds were not observed in all specimens, and the overall gross appearance similar to that of native IVCs. Immunohistological staining revealed the presence of factor VIII positive nucleated cells at the luminal surface of the TEVAs. In addition, lesions were observed where alpha-smooth muscle actin and desmin positive cells existed. Implanted TEVAs contained a sufficient amount of extracellular matrix, and showed neither occlusion nor aneurysmal formation. In addition, endothelial cells were found to line the luminal surface of each TEVA. These results strongly suggest that "ideal" venous grafts with antithrombogenicity can be produced.