Reconstruction for Skull Base Defect Using Fat-Containing Perifascial Areolar Tissue.

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Choi, Woo Young; Sung, Ki Wook; Kim, Young Seok; Hong, Jong Won; Roh, Tai Suk; Lew, Dae Hyun; Chang, Jong Hee; Lee, Kyu Sung

2017-06-01

Skull base reconstruction is a challenging task. The method depends on the anatomical complexity and size of the defect. We obtained tissue by harvesting fat-containing perifascial areolar tissue (PAT) for reconstruction of limited skull base defects and volume augmentation. We demonstrated the effective option for reconstruction of limited skull base defects and volume augmentation. From October 2013 to November 2015, 5 patients underwent operations using fat-containing PAT to fill the defect in skull base and/or perform volume replacement in the forehead. Perifascial areolar tissue with 5- to 10-mm fat thickness was harvested from the inguinal region. The fat-containing PAT was grafted to the defect contacting the vascularized wound bed. Patients were followed up in terms of their clinical symptoms and postoperative magnetic resonance imaging findings. Four patients were treated using fat-containing PAT after tumor resection. One patient was treated for a posttraumatic forehead depression deformity. The fat-containing PAT included 5- to 9-mm fat thickness in all cases. The mean size of grafted PAT was 65.6 cm (28-140 cm). The mean follow-up period was 18.6 months (12-31 months). There was no notable complication. There was no donor site morbidity. We can harvest PAT with fat easily and obtain the sufficient volume to treat the defect. It also could be used with other reconstructive method, such as a free flap or a regional flap to fill the left dead space. Therefore, fat-containing PAT could be additional options to reconstruction of skull base defect.

Improved repair of bone defects with prevascularized tissue-engineered bones constructed in a perfusion bioreactor.

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Li, De-Qiang; Li, Ming; Liu, Pei-Lai; Zhang, Yuan-Kai; Lu, Jian-Xi; Li, Jian-Min

2014-10-01

Vascularization of tissue-engineered bones is critical to achieving satisfactory repair of bone defects. The authors investigated the use of prevascularized tissue-engineered bone for repairing bone defects. The new bone was greater in the prevascularized group than in the non-vascularized group, indicating that prevascularized tissue-engineered bone improves the repair of bone defects. [Orthopedics. 2014; 37(10):685-690.]. Copyright 2014, SLACK Incorporated.

Efficacy of Connective Tissue with and without Periosteum in Regeneration of Intrabony Defects

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Vahid Esfahanian

2014-12-01

Full Text Available Background and aims. Connective tissue grafts with and without periosteum is used in regenerative treatments of bone and has demonstrated successful outcomes in previous investigations. The aim of present study was to evaluate the effec-tiveness of connective tissue graft with and without periosteum in regeneration of intrabony defects. Materials and methods. In this single-blind randomized split-mouth clinical trial, 15 pairs of intrabony defects in 15 pa-tients with moderate to advanced periodontitis were treated by periosteal connective tissue graft + ABBM (test group or non-periosteal connective tissue graft + ABBM (control group. Probing pocket depth, clinical attachment level, free gingi-val margin position, bone crestal position, crest defect depth and defect depth to stent were measured at baseline and after six months by surgical re-entry. Data was analyzed by Student’s t-test and paired t-tests (α=0.05. Results. Changes in clinical parameters after 6 months in the test and control groups were as follows: mean of PPD reduc-tion: 3.1±0.6 (P<0.0001; 2.5±1.0 mm (P<0.0001, CAL gain: 2.3±0.9 (P<0.0001; 2.2±1.0 mm (P<0.0001, bone fill: 2.2±0.7 mm (P<0.0001; 2.2±0.7 mm (P<0.0001, respectively. No significant differences in the position of free gingival margin were observed during 6 months compared to baseline in both groups. Conclusion. Combinations of periosteal connective tissue graft + ABBM and non-periosteal connective tissue graft + ABBM were similarly effective in treating intrabony defects without any favor for any group. Connective tissue and perio-steum can be equally effective in regeneration of intrabony defects.

Implantation of autogenous meniscal fragments wrapped with a fascia sheath enhances fibrocartilage regeneration in vivo in a large harvest site defect.

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Kobayashi, Yasukazu; Yasuda, Kazunori; Kondo, Eiji; Katsura, Taro; Tanabe, Yoshie; Kimura, Masashi; Tohyama, Harukazu

2010-04-01

Concerning meniscal tissue regeneration, many investigators have studied the development of a tissue-engineered meniscus. However, the utility still remains unknown. Implantation of autogenous meniscal fragments wrapped with a fascia sheath into the donor site meniscal defect may significantly enhance fibrocartilage regeneration in vivo in the defect. Controlled laboratory study. Seventy-five mature rabbits were used in this study. In each animal, an anterior one-third of the right medial meniscus was resected. Then, the animals were divided into the following 3 groups of 25 rabbits each: In group 1, no treatment was applied to the meniscal defect. In group 2, the defect was covered with a fascia sheath. In group 3, after the resected meniscus was fragmented into small pieces, the fragments were grafted into the defect. Then, the defect with the meniscal fragments was covered with a fascia sheath. In each group, 5 rabbits were used for histological evaluation at 3, 6, and 12 weeks after surgery, and 5 rabbits were used for biomechanical evaluation at 6 and 12 weeks after surgery. Histologically, large round cells in group 3 were scattered in the core portion of the meniscus-shaped tissue, and the matrix around these cells was positively stained by safranin O and toluisin blue at 12 weeks. The histological score of group 3 was significantly higher than that of group 1 and group 2. Biomechanically, the maximal load and stiffness of group 3 were significantly greater than those of groups 1 and 2. This study clearly demonstrated that implantation of autogenous meniscal fragments wrapped with a fascia sheath into the donor site meniscal defect significantly enhanced fibrocartilage regeneration in vivo in the defect at 12 weeks after implantation in the rabbit. This study proposed a novel strategy to treat a large defect after a meniscectomy.

A puzzle assembly strategy for fabrication of large engineered cartilage tissue constructs.

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Nover, Adam B; Jones, Brian K; Yu, William T; Donovan, Daniel S; Podolnick, Jeremy D; Cook, James L; Ateshian, Gerard A; Hung, Clark T

2016-03-21

Engineering of large articular cartilage tissue constructs remains a challenge as tissue growth is limited by nutrient diffusion. Here, a novel strategy is investigated, generating large constructs through the assembly of individually cultured, interlocking, smaller puzzle-shaped subunits. These constructs can be engineered consistently with more desirable mechanical and biochemical properties than larger constructs (~4-fold greater Young׳s modulus). A failure testing technique was developed to evaluate the physiologic functionality of constructs, which were cultured as individual subunits for 28 days, then assembled and cultured for an additional 21-35 days. Assembled puzzle constructs withstood large deformations (40-50% compressive strain) prior to failure. Their ability to withstand physiologic loads may be enhanced by increases in subunit strength and assembled culture time. A nude mouse model was utilized to show biocompatibility and fusion of assembled puzzle pieces in vivo. Overall, the technique offers a novel, effective approach to scaling up engineered tissues and may be combined with other techniques and/or applied to the engineering of other tissues. Future studies will aim to optimize this system in an effort to engineer and integrate robust subunits to fill large defects. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cell based bone tissue engineering in jaw defects

NARCIS (Netherlands)

Meijer, Gert J.; de Bruijn, Joost Dick; Koole, Ron; van Blitterswijk, Clemens

2008-01-01

In 6 patients the potency of bone tissue engineering to reconstruct jaw defects was tested. After a bone marrow aspirate was taken, stem cells were cultured, expanded and grown for 7 days on a bone substitute in an osteogenic culture medium to allow formation of a layer of extracellular bone matrix.

Connective tissue graft as a biological barrier for guided tissue regeneration in intrabony defects: a histological study in dogs.

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Ribeiro, Fernando Salimon; Pontes, Ana Emília Farias; Zuza, Elizangela Partata; da Silva, Vanessa Camila; Lia, Raphael Carlos Comelli; Marcantonio Junior, Elcio

2015-06-01

The use of the autogenous periosteal graft as biological barrier has been proposed for periodontal regeneration. The aim of this study was to evaluate the histometric findings of the subepithelial connective tissue graft as barrier in intrabony defects compared to a bioabsorbable membrane. Three-walled intrabony defects were created surgically in the mesial aspect of the right and left maxillary canines in five healthy mongrel dogs. The defects were chronified, and two types of barriers were randomly carried out for guided tissue regeneration in a split-mouth design: the test group with a subepithelial connective tissue graft and the control group with a bioabsorbable membrane. The specimens were processed for histometric analyses of the epithelium (E), connective tissue (CT), newly formed cementum (NC), new bone (NB), and total newly formed tissues (NFT). The test side showed smaller mean of NC (3.6 ± 1.2), NB (2.1 ± 0.7), and NFT (7.7 ± 0.8) than the control group (NC 7.3 ± 0.5; NB 5.3 ± 1.3; NFT 10.1 ± 2.2; P  0.05) and CT (test 2.5 ± 1.1; control 2.0 ± 0.5; P > 0.05) between groups. The bioabsorbable membrane was more effective in maintaining the space for periodontal regeneration than periosteal connective graft when used as barrier. The bioabsorbable membrane showed more favorable regenerative results in intrabony defects in dogs than the subepithelial connective tissue graft as biological barrier.

Soft Tissue Reconstruction of Complete Circumferential Defects of the Upper Extremity

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Zhi Yang Ng

2017-03-01

Full Text Available BackgroundUpper extremity soft tissue defects with complete circumferential involvement are not common. Coupled with the unique anatomy of the upper extremity, the underlying etiology of such circumferential soft tissue defects represent additional reconstructive challenges that require treatment to be tailored to both the patient and the wound. The aim of this study is to review the various options for soft tissue reconstruction of complete circumferential defects in the upper extremity.MethodsA literature review of PubMed and MEDLINE up to December 2016 was performed. The current study focuses on forearm and arm defects from the level at or proximal to the wrist and were assessed based on Tajima's classification (J Trauma 1974. Data reviewed for analysis included patient demographics, causality, defect size, reconstructive technique(s employed, and postoperative follow-up and functional outcomes (when available.ResultsIn accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, 14 unique articles were identified for a total of 50 patients (mean=28.1 years. Underlying etiologies varied from extensive thermal or electrical burns to high impact trauma leading to degloving or avulsion, crush injuries, or even occur iatrogenically after tumor extirpation or extensive debridement. Treatment options ranged from the application of negative pressure wound dressings to the opposite end of the spectrum in hand transplantation.ConclusionsWith the evolution of reconstructive techniques over time, the extent of functional and aesthetic rehabilitation of these complex upper extremity injuries has also improved. The proposed management algorithm comprehensively addresses the inherent challenges associated with these complex cases.

Current Therapeutic Strategies for Adipose Tissue Defects/Repair Using Engineered Biomaterials and Biomolecule Formulations

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Christopher M. Mahoney

2018-05-01

Full Text Available Tissue engineered scaffolds for adipose restoration/repair has significantly evolved in recent years. Patients requiring soft tissue reconstruction, caused by defects or pathology, require biomaterials that will restore void volume with new functional tissue. The gold standard of autologous fat grafting (AFG is not a reliable option. This review focuses on the latest therapeutic strategies for the treatment of adipose tissue defects using biomolecule formulations and delivery, and specifically engineered biomaterials. Additionally, the clinical need for reliable off-the-shelf therapies, animal models, and challenges facing current technologies are discussed.

Current Therapeutic Strategies for Adipose Tissue Defects/Repair Using Engineered Biomaterials and Biomolecule Formulations.

Science.gov (United States)

Mahoney, Christopher M; Imbarlina, Cayla; Yates, Cecelia C; Marra, Kacey G

2018-01-01

Tissue engineered scaffolds for adipose restoration/repair has significantly evolved in recent years. Patients requiring soft tissue reconstruction, caused by defects or pathology, require biomaterials that will restore void volume with new functional tissue. The gold standard of autologous fat grafting (AFG) is not a reliable option. This review focuses on the latest therapeutic strategies for the treatment of adipose tissue defects using biomolecule formulations and delivery, and specifically engineered biomaterials. Additionally, the clinical need for reliable off-the-shelf therapies, animal models, and challenges facing current technologies are discussed.

Engraftment of Prevascularized, Tissue Engineered Constructs in a Novel Rabbit Segmental Bone Defect Model

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Alexandre Kaempfen

2015-06-01

Full Text Available The gold standard treatment of large segmental bone defects is autologous bone transfer, which suffers from low availability and additional morbidity. Tissue engineered bone able to engraft orthotopically and a suitable animal model for pre-clinical testing are direly needed. This study aimed to evaluate engraftment of tissue-engineered bone with different prevascularization strategies in a novel segmental defect model in the rabbit humerus. Decellularized bone matrix (Tutobone seeded with bone marrow mesenchymal stromal cells was used directly orthotopically or combined with a vessel and inserted immediately (1-step or only after six weeks of subcutaneous “incubation” (2-step. After 12 weeks, histological and radiological assessment was performed. Variable callus formation was observed. No bone formation or remodeling of the graft through TRAP positive osteoclasts could be detected. Instead, a variable amount of necrotic tissue formed. Although necrotic area correlated significantly with amount of vessels and the 2-step strategy had significantly more vessels than the 1-step strategy, no significant reduction of necrotic area was found. In conclusion, the animal model developed here represents a highly challenging situation, for which a suitable engineered bone graft with better prevascularization, better resorbability and higher osteogenicity has yet to be developed.

Digital design of scaffold for mandibular defect repair based on tissue engineering.

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Liu, Yun-feng; Zhu, Fu-dong; Dong, Xing-tao; Peng, Wei

2011-09-01

Mandibular defect occurs more frequently in recent years, and clinical repair operations via bone transplantation are difficult to be further improved due to some intrinsic flaws. Tissue engineering, which is a hot research field of biomedical engineering, provides a new direction for mandibular defect repair. As the basis and key part of tissue engineering, scaffolds have been widely and deeply studied in regards to the basic theory, as well as the principle of biomaterial, structure, design, and fabrication method. However, little research is targeted at tissue regeneration for clinic repair operations. Since mandibular bone has a special structure, rather than uniform and regular structure in existing studies, a methodology based on tissue engineering is proposed for mandibular defect repair in this paper. Key steps regarding scaffold digital design, such as external shape design and internal microstructure design directly based on triangular meshes are discussed in detail. By analyzing the theoretical model and the measured data from the test parts fabricated by rapid prototyping, the feasibility and effectiveness of the proposed methodology are properly verified. More works about mechanical and biological improvements need to be done to promote its clinical application in future.

Digital design of scaffold for mandibular defect repair based on tissue engineering

Institute of Scientific and Technical Information of China (English)

Yun-feng LIU; Fu-dong ZHU; Xing-tao DONG; Wei PENG

2011-01-01

Mandibular defect occurs more frequently in recent years,and clinical repair operations via bone transplantation are difficult to be further improved due to some intrinsic flaws.Tissue engineering,which is a hot research field of biomedical engineering,provides a new direction for mandibular defect repair.As the basis and key part of tissue engineering,scaffolds have been widely and deeply studied in regards to the basic theory,as well as the principle of biomaterial,structure,design,and fabrication method.However,little research is targeted at tissue regeneration for clinic repair operations.Since mandibular bone has a special structure,rather than uniform and regular structure in existing studies,a methodology based on tissue engineering is proposed for mandibular defect repair in this paper.Key steps regarding scaffold digital design,such as external shape design and internal microstructure design directly based on triangular meshes are discussed in detail.By analyzing the theoretical model and the measured data from the test parts fabricated by rapid prototyping,the feasibility and effectiveness of the proposed methodology are properly verified.More works about mechanical and biological improvements need to be done to promote its clinical application in future.

Biomimetic coatings for bone tissue engineering of critical-sized defects

NARCIS (Netherlands)

Liu, Y.; Wu, G.; de Groot, K.

2010-01-01

The repair of critical-sized bone defects is still challenging in the fields of implantology, maxillofacial surgery and orthopaedics. Current therapies such as autografts and allografts are associated with various limitations. Cytokine-based bone tissue engineering has been attracting increasing

Defect testing of large aperture optics based on high resolution CCD camera

International Nuclear Information System (INIS)

Cheng Xiaofeng; Xu Xu; Zhang Lin; He Qun; Yuan Xiaodong; Jiang Xiaodong; Zheng Wanguo

2009-01-01

A fast testing method on inspecting defects of large aperture optics was introduced. With uniform illumination by LED source at grazing incidence, the image of defects on the surface of and inside the large aperture optics could be enlarged due to scattering. The images of defects were got by high resolution CCD camera and microscope, and the approximate mathematical relation between viewing dimension and real dimension of defects was simulated. Thus the approximate real dimension and location of all defects could be calculated through the high resolution pictures. (authors)

Optimising Aesthetic Reconstruction of Scalp Soft Tissue by an Algorithm Based on Defect Size and Location.

Science.gov (United States)

Ooi, Adrian Sh; Kanapathy, Muholan; Ong, Yee Siang; Tan, Kok Chai; Tan, Bien Keem

2015-11-01

Scalp soft tissue defects are common and result from a variety of causes. Reconstructive methods should maximise cosmetic outcomes by maintaining hair-bearing tissue and aesthetic hairlines. This article outlines an algorithm based on a diverse clinical case series to optimise scalp soft tissue coverage. A retrospective analysis of scalp soft tissue reconstruction cases performed at the Singapore General Hospital between January 2004 and December 2013 was conducted. Forty-one patients were included in this study. The majority of defects aesthetic outcome while minimising complications and repeat procedures.

Using radionuclide imaging for monitoring repairment of bone defect with tissue-engineered bone graft in rabbits

International Nuclear Information System (INIS)

Xia Changsuo; Ye Fagang; Zou Yunwen; Ji Shixiang; Wang Dengchun

2004-01-01

Objective: To observe the effect of tissue-engineered bone grafts in repairing bone defect in rabbits, and assess the value of radionuclide for monitoring the therapeutic effect of this approach. Methods: Bilateral radial defects of 15 mm in length in 24 rabbits were made. The tissue-engineered bone grafts (composite graft) contained bone marrow stromal cells (BMSCs) of rabbits and calcium phosphate cement (CPC) were grafted in left side defects, CPC only grafts (artificial bone graft) in right defects. After the operation, radionuclide was used to monitor the therapeutic effects at 4, 8 and 12 weeks. Results: 99 Tc m -methylene diphosphonic acid (MDP) radionuclide bone imaging indicated that there was more radionuclide accumulation in grafting region of composite than that of CPC. There was significant difference between 99 Tc m -MDP uptake of the region of interest (ROI) and scintillant counts of composite bone and the artificial bone (P<0.01). Conclusion: Tissue-engineered bone grafts is eligible for repairing radial bone defects, and radionuclide imaging may accurately monitor the revascularization and bone regeneration after the bone graft implantation. (authors)

Clinical investigation of large perfusion defect cases with 201Tl exercise myocardial scintigraphy

International Nuclear Information System (INIS)

Morota, Motoi; Kobayashi, Yasuhiko

1999-01-01

We investigated retrospectively the clinical significance of large perfusion defect on 201 Thallium myocardial scintigraphy from the records of 833 patients during the past 3 years from 1991 to 1994. The patients were divided into 3 groups according to the extent of perfusion defect; cases with normal perfusion (n=561), with small perfusion defect (n=211) and with large perfusion defect (n=61). We found that the proportions of cases with large perfusion defect was significantly larger than that of cases with small perfusion defect in myocardial disease (MD; hypertrophic cardiomyopathy, dilated cardiomyopathy, and post myocarditis combined) (P 201 Thallium myocardial scintigraphy and that complication of diabetes mellitus and clinical symptoms may be useful in differentiating IHD from MD. (author)

Use of autologous tissue engineered skin to treat porcine full-thickness skin defects

Institute of Scientific and Technical Information of China (English)

CAI Xia; CAO Yi-lin; CUI Lei; LIU Wei; GUAN Wen-xiang

2005-01-01

Objective: To explore a feasible method to repair full-thickness skin defects utilizing tissue engineered techniques. Methods: The Changfeng hybrid swines were used and the skin specimens were cut from the posterior limb girdle region, from which the keratinocytes and fibroblasts were isolated and harvested by trypsin, EDTA, and type II collagenase. The cells were seeded in Petri dishes for primary culture. When the cells were in logarithmic growth phase, they were treated with trypsin to separate them from the floor of the tissue culture dishes. A biodegradable material, Pluronic F-127, was prefabricated and mixed with these cells, and then the cell-Pluronic compounds were seeded evenly into a polyglycolic acid (PGA). Then the constructs were replanted to the autologous animals to repair the full-thickness skin defects. Histology and immunohistochemistry of the neotissue were observed in 1, 2, 4, and 8 postoperative weeks. Results: The cell-Pluronic F-127-PGA compounds repaired autologous full-thickness skin defects 1 week after implantation. Histologically, the tissue engineered skin was similar to the normal skin with stratified epidermis overlying a moderately thick collageneous dermis. Three of the structural proteins in the epidermal basement membrane zone, type IV collagen, laminin, and type VII collagen were detected using immunohistochemical methods. Conclusions: By studying the histology and immunohistochemistry of the neotissue, the bioengineered skin graft holds great promise for improving healing of the skin defects.

Implant-retained skull prosthesis to cover a large defect of the hairy skull resulting from treatment of a basal cell carcinoma: A clinical report.

Science.gov (United States)

Hoekstra, Jitske; Vissink, Arjan; Raghoebar, Gerry M; Visser, Anita

2017-05-01

Skin carcinoma, particularly basal cell carcinoma, and its treatment can result in large defects of the hairy skull. A 53-year-old man is described who was surgically treated for a large basal cell carcinoma invading the skin and underlying tissue at the top of the hairy skull. Treatment consisted of resecting the tumor and external part of the skull bone. To protect the brain and to cover the defect of the hairy skull, an acrylic resin skull prosthesis with hair was designed to mask the defect. The skull prosthesis was retained on 8 extraoral implants placed at the margins of the defect in the skull bone. The patient was satisfied with the treatment outcome. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Implant-retained skull prosthesis to cover a large defect of the hairy skull resulting from treatment of a basal cell carcinoma : A clinical report

NARCIS (Netherlands)

Hoekstra, Jitske; Vissink, Arjan; Raghoebar, Gerry M; Visser, Anita

Skin carcinoma, particularly basal cell carcinoma, and its treatment can result in large defects of the hairy skull. A 53-year-old man is described who was surgically treated for a large basal cell carcinoma invading the skin and underlying tissue at the top of the hairy skull. Treatment consisted

Reconstruction of soft tissue defects around the ankle and foot

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Bharat Bhushan Dogra

2014-01-01

Full Text Available Introduction: Soft tissue defects over ankle and foot region are encountered quite frequently following road traffic trauma and surgery. Management of such cases is a challenging task for any reconstructive surgeon because of paucity of skin and relative poor vascular status of skin in this region. Hence, invariably such cases require microsurgical free flap coverage, expertise for which may not be available at all the centers, such procedures require long operating hours and suitable recipient vessel may not be available in crush injuries. Materials and Methods: Thirty consecutive patients having soft tissue defects around ankle and foot region who underwent various reconstructive procedures in a medical college hospital during last 2 years form the basis of this study. This study was carried out to enlist various etiological factors and reconstructive surgical procedures employed to manage such cases without microsurgery. Results: The age of these patients ranged from 9 to 72 years. Twenty-five patients were males while 05 were females, with a mean age of 25 years. Road traffic accidents happened to be the primary cause of such defects in as many as 15 patients, cycle spoke trauma in 02 patients, implant exposure following orthopedic surgery in 6 patients, diabetic angiopathy in 4 patients and chronic osteomyelitis in 3 patients. The site of the defect was lower fourth of tibia in 16 patients, dorsum of foot in 2 patients, sole in 5 patients, medial aspect of ankle in 02 cases, lateral aspect in 02 cases and retro calcaneal region in 03 cases. In 10 cases distally based superficial sural artery flap was used to reconstruct the defect. In step rotation flap was used to provide sensory flap cover in the weight bearing heel in 04 cases. Inferiorly based fasciocutanenous flaps in 09 cases and muscle flaps were used in 07 cases. Conclusion: Distally based sural artery based flaps are very handy to provide skin cover around ankle and malleolar

Novel Therapy for Bone Regeneration in Large Segmental Defects

Science.gov (United States)

2017-12-01

can maintain bone length and allow successfully regeneration in segmental defects. r 2006 Elsevier Ltd. All rights reserved. Keywords: Bone...pre- formed endothelial networks, as the MSCs can act as pericytes to the newly formed blood vessels. Pirraco et al. [159] also cultured ECs and...AWARD NUMBER: W81XWH-13-1-0407 TITLE: Novel Therapy for Bone Regeneration in Large Segmental Defects PRINCIPAL INVESTIGATOR: Melissa Kacena

Comparison of procedures for immediate reconstruction of large osseous defects resulting from removal of a single tooth to prepare for insertion of an endosseous implant after healing

NARCIS (Netherlands)

Raghoebar, G. M.; Slater, J. J. H.; den Hartog, L.; Meijer, H. J. A.; Vissink, A.

This study evaluated the treatment outcome of immediate reconstruction of 45 large osseous defects resulting from removal of a single tooth with a 1:2 mixture of Bio-Oss(R) and autologous tuberosity bone, and three different procedures for soft tissue closing (Bio-Gide(R) membrane, connective tissue

Nasal chondrocyte-based engineered autologous cartilage tissue for repair of articular cartilage defects: an observational first-in-human trial.

Science.gov (United States)

Mumme, Marcus; Barbero, Andrea; Miot, Sylvie; Wixmerten, Anke; Feliciano, Sandra; Wolf, Francine; Asnaghi, Adelaide M; Baumhoer, Daniel; Bieri, Oliver; Kretzschmar, Martin; Pagenstert, Geert; Haug, Martin; Schaefer, Dirk J; Martin, Ivan; Jakob, Marcel

2016-10-22

defect filling and development of repair tissue approaching the composition of native cartilage. Hyaline-like cartilage tissues, engineered from autologous nasal chondrocytes, can be used clinically for repair of articular cartilage defects in the knee. Future studies are warranted to assess efficacy in large controlled trials and to investigate an extension of indications to early degenerative states or to other joints. Deutsche Arthrose-Hilfe. Copyright © 2016 Elsevier Ltd. All rights reserved.

Use of the Anterolateral Thigh and Vertical Rectus Abdominis Musculocutaneous Flaps as Utility Flaps in Reconstructing Large Groin Defects

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Edwin Jonathan Aslim

2014-09-01

Full Text Available BackgroundGroin dissections result in large wounds with exposed femoral vessels requiring soft tissue coverage, and the reconstructive options are diverse. In this study we reviewed our experience with the use of the pedicled anterolateral thigh and vertical rectus abdominis musculocutaneous flaps in the reconstruction of large groin wounds.MethodsGroin reconstructions performed over a period of 10 years were evaluated, with a mean follow up of two years. We included all cases with large or complex (involving perineum defects, which were reconstructed with the pedicled anterolateral thigh musculocutaneous or the vertical rectus abdominis musculocutaneous (VRAM flaps. Smaller wounds which were covered with skin grafts, locally based flaps and pedicled muscle flaps were excluded.ResultsTwenty-three reconstructions were performed for large or complex groin defects, utilising the anterolateral thigh (n=10 and the vertical rectus abdominis (n=13 pedicled musculocutaneous flaps. Femoral vein reconstruction with a prosthetic graft was required in one patient, and a combination flap (VRAM and gracilis muscle flap was performed in another. Satisfactory coverage was achieved in all cases without major complications. No free flaps were used in our series.ConclusionsThe anterolateral thigh and vertical rectus abdominis pedicled musculocutaneous flaps yielded consistent results with little morbidity in the reconstruction of large and complex groin defects. A combination of flaps can be used in cases requiring extensive cover.

The effect of a composite of polyorthoester and demineralized bone on the healing of large segmental defects of the radius in rats

DEFF Research Database (Denmark)

Solheim, E; Pinholt, E M; Andersen, R

1992-01-01

The effect of a composite of demineralized bone mixed with polyorthoester on the healing of large segmental defects in the rat radius was studied. Sixty male Wistar rats were divided into four groups, A through D, and an osteoperiosteal diaphyseal defect of 50 per cent of the length of the bone....... The formation of bone in the defects was quantified with computer-assisted measurements of the area on radiographs. The host-tissue response was evaluated with light microscopy. Defects that had been filled with the composite of polyorthoester and demineralized bone or with demineralized bone alone showed...... regeneration of bone corresponding to 93.6 and 77.6 per cent of the area of the defect, respectively. Defects that had no implant or that had been filled with polyorthoester alone showed significantly less formation of bone. No inflammation was seen with light microscopy, and only traces of the polyorthoester...

Matrix-induced autologous chondrocyte implantation for a large chondral defect in a professional football player: a case report

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Beyzadeoglu Tahsin

2012-06-01

Full Text Available Abstract Introduction Matrix-assisted autologous chondrocyte implantation is a well-known procedure for the treatment of cartilage defects, which aims to establish a regenerative milieu and restore hyaline cartilage. However, much less is known about third-generation autologous chondrocyte implantation application in high-level athletes. We report on the two-year follow-up outcome after matrix-assisted autologous chondrocyte implantation to treat a large cartilage lesion of the lateral femoral condyle in a male Caucasian professional football player. Case presentation A 27-year-old male Caucasian professional football player was previously treated for cartilage problems of his left knee with two failed microfracture procedures resulting in a 9 cm2 Outerbridge Grade 4 chondral lesion at his lateral femoral condyle. Preoperative Tegner-Lysholm and Brittberg-Peterson scores were 64 and 58, and by the second year they were 91 and 6. An evaluation with magnetic resonance imaging demonstrated filling of the defect with the signal intensity of the repair tissue resembling healthy cartilage. Second-look arthroscopy revealed robust, smooth cartilage covering his lateral femoral condyle. He returned to his former competitive level without restrictions or complaints one year after the procedure. Conclusions This case illustrates that robust cartilage tissue can be obtained with a matrix-assisted autologous chondrocyte implantation procedure even after two failed microfracture procedures in a large (9 cm2 cartilage defect. To the best of our knowledge, this is the first case report on the application of the third-generation cell therapy treatment technique, matrix-assisted autologous chondrocyte implantation, in a professional football player.

Digital detection system of surface defects for large aperture optical elements

International Nuclear Information System (INIS)

Fan Yong; Chen Niannian; Gao Lingling; Jia Yuan; Wang Junbo; Cheng Xiaofeng

2009-01-01

Based on the light defect images against the dark background in a scattering imaging system, a digital detection system of surface defects for large aperture optical elements has been presented. In the system, the image is segmented by a multi-area self-adaptive threshold segmentation method, then a pixel labeling method based on replacing arrays is adopted to extract defect features quickly, and at last the defects are classified through back-propagation neural networks. Experiment results show that the system can achieve real-time detection and classification. (authors)

The "Batman flap": a novel technique to repair a large central glabellar defect.

Science.gov (United States)

Puviani, Mario; Curci, Marco

2018-04-01

Given the critical position of central glabella among the frontal, nasal, and supraorbital aesthetic subunits of the face, the reconstruction of large defects in this area represents a surgical challenge. We describe a surgical technique based on a modified, curved, A-T flap to repair a large glabellar defect. Our modification is useful for large glabellar defects because it enables the distribution of the tension all over the reconstruction sides, avoiding a stressed central area and the subsequent risk of necrosis; functionally, it respects the eyebrows position and since the advancement is parallel to their major axes, it avoids the reduction of the distance between them. The "Batman flap" enables reconstructing a glabellar defect, with a good aesthetical result and the respect of the relevant aesthetical subunits. © 2017 The International Society of Dermatology.

On the connective tissue regulator Follistatin-like 1

NARCIS (Netherlands)

Sylva, M.

2014-01-01

Even though for many years the molecular mechanisms underlying cardiac development have been studied, the majority of cardiac defects remain unexplained. Defects in the cardiac connective tissue component result in a large proportion of heart defects such as valve and septal defects. Previous

Autologous chondrocyte implantation: Is it likely to become a saviour of large-sized and full-thickness cartilage defect in young adult knee?

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Zhang, Chi; Cai, You-Zhi; Lin, Xiang-Jin

2016-05-01

A literature review of the first-, second- and third-generation autologous chondrocyte implantation (ACI) technique for the treatment of large-sized (>4 cm(2)) and full-thickness knee cartilage defects in young adults was conducted, examining the current literature on features, clinical scores, complications, magnetic resonance image (MRI) and histological outcomes, rehabilitation and cost-effectiveness. A literature review was carried out in the main medical databases to evaluate the several studies concerning ACI treatment of large-sized and full-thickness knee cartilage defects in young adults. ACI technique has been shown to relieve symptoms and improve functional assessment in large-sized (>4 cm(2)) and full-thickness knee articular cartilage defect of young adults in short- and medium-term follow-up. Besides, low level of evidence demonstrated its efficiency and durability at long-term follow-up after implantation. Furthermore, MRI and histological evaluations provided the evidence that graft can return back to the previous nearly normal cartilage via ACI techniques. Clinical outcomes tend to be similar in different ACI techniques, but with simplified procedure, low complication rate and better graft quality in the third-generation ACI technique. ACI based on the experience of cell-based therapy, with the high potential to regenerate hyaline-like tissue, represents clinical development in treatment of large-sized and full-thickness knee cartilage defects. IV.

Mesenchymal stem cells-seeded bio-ceramic construct for bone regeneration in large critical-size bone defect in rabbit

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Maiti SK

2016-11-01

Full Text Available Bone marrow derived mesenchymal stem cells (BMSC represent an attractive cell population for tissue engineering purpose. The objective of this study was to determine whether the addition of recombinant human bone morphogenetic protein (rhBMP-2 and insulin-like growth factor (IGF-1 to a silica-coated calcium hydroxyapatite (HASi - rabbit bone marrow derived mesenchymal stem cell (rBMSC construct promoted bone healing in a large segmental bone defect beyond standard critical -size radial defects (15mm in rabbits. An extensively large 30mm long radial ostectomy was performed unilaterally in thirty rabbits divided equally in five groups. Defects were filled with a HASi scaffold only (group B; HASi scaffold seeded with rBMSC (group C; HASi scaffold seeded with rBMSC along with rhBMP-2 and IGF-1 in groups D and E respectively. The same number of rBMSC (five million cells and concentration of growth factors rhBMP-2 (50µg and IGF-1 (50µg was again injected at the site of bone defect after 15 days of surgery in their respective groups. An empty defect served as the control group (group A. Radiographically, bone healing was evaluated at 7, 15, 30, 45, 60 and 90 days post implantation. Histological qualitative analysis with microCT (µ-CT, haematoxylin and eosin (H & E and Masson’s trichrome staining were performed 90 days after implantation. All rhBMP-2-added constructs induced the formation of well-differentiated mineralized woven bone surrounding the HASi scaffolds and bridging bone/implant interfaces as early as eight weeks after surgery. Bone regeneration appeared to develop earlier with the rhBMP-2 constructs than with the IGF-1 added construct. Constructs without any rhBMP-2 or IGF-1 showed osteoconductive properties limited to the bone junctions without bone ingrowths within the implantation site. In conclusion, the addition of rhBMP-2 to a HASi scaffold could promote bone generation in a large critical-size-defect.

Xenoimplantation of an Extracellular-Matrix-Derived, Biphasic, Cell-Scaffold Construct for Repairing a Large Femoral-Head High-Load-Bearing Osteochondral Defect in a Canine Model

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Yang Qiang

2014-01-01

Full Text Available This study was aimed to develop an ECM-derived biphasic scaffold and to investigate its regeneration potential loaded with BM-MSCs in repair of large, high-load-bearing osteochondral defects of the canine femoral head. The scaffolds were fabricated using cartilage and bone ECM as a cartilage and bone layer, respectively. Osteochondral constructs were fabricated using induced BM-MSCs and the scaffold. Osteochondral defects (11 mm diameter × 10 mm depth were created on femoral heads of canine and treated with the constructs. The repaired tissue was evaluated for gross morphology, radiography, histological, biomechanics at 3 and 6 months after implantation. Radiography revealed that femoral heads slightly collapsed at 3 months and severely collapsed at 6 months. Histology revealed that some defects in femoral heads were repaired, but with fibrous tissue or fibrocartilage, and femoral heads with different degrees of collapse. The bone volume fraction was lower for subchondral bone than normal femoral bone at 3 and 6 months. Rigidity was lower in repaired subchondral bone than normal femoral bone at 6 months. The ECM-derived, biphasic scaffold combined with induced BM-MSCs did not successfully repair large, high-load-bearing osteochondral defects of the canine femoral head. However, the experience can help improve the technique of scaffold fabrication and vascularization.

Flow-Through Free Fibula Osteocutaneous Flap in Reconstruction of Tibial Bone, Soft Tissue, and Main Artery Segmental Defects.

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Li, Zonghuan; Yu, Aixi; Qi, Baiwen; Pan, Zhenyu; Ding, Junhui

2017-08-01

The aim of this report was to present the use of flow-through free fibula osteocutaneous flap for the repair of complex tibial bone, soft tissue, and main artery segmental defects. Five patients with bone, soft tissue, and segmental anterior tibial artery defects were included. The lengths of injured tibial bones ranged from 4 to 7 cm. The sizes of impaired soft tissues were between 9 × 4 and 15 × 6 cm. The lengths of defect of anterior tibial artery segments ranged from 6 to 10 cm. Two patients had distal limb perfusion problems. Flow-through free fibula osteocutaneous flap was performed for all 5 patients. Patients were followed for 12 to 18 months. All wounds healed after 1-stage operation, and all flow-through flaps survived. The distal perfusion after vascular repair was normal in all patients. Superficial necrosis of flap edge was noted in 1 case. After the local debridement and partial thickness skin graft, the flap healed uneventfully, and the surgical operation did not increase injury to the donor site. Satisfactory bone union was achieved in all patients in 2 to 4 months postoperation. Enlargement of fibula graft was observed during follow-up from 12 to 18 months. The functions of adjacent joints were recovered, and all patients were able to walk normally. Flow-through free fibula osteocutaneous flap was shown to be an effective and efficient technique for repairing composite tibial bone, soft tissue, and main artery segmental defects. This 1-stage operation should be useful in clinical practice for the treatment of complex bone, soft tissue, and vessel defects.

Optimization of Soft Tissue Management, Spacer Design, and Grafting Strategies for Large Segmental Bone Defects using the Chronic Caprine Tibial Defect Model

Science.gov (United States)

2015-12-01

for this animal revealed an abscess at the defect site with cultures identifying Staphylococcus aureus infection . Another animal (15G11) developed...foreign body reaction and expose a bleeding vascular surface significantly increased bone formation in the defect site. Adding texture to a smooth...ACHIEVEMENTS: Nothing to report 10. REFERENCES: 1. Johnson, E.N., et al., Infectious complications of open type III tibial fractures among combat

Repair of articular cartilage defects by tissue-engineered cartilage constructed with adipose-derived stem cells and acellular cartilaginous matrix in rabbits.

Science.gov (United States)

Wang, Z J; An, R Z; Zhao, J Y; Zhang, Q; Yang, J; Wang, J B; Wen, G Y; Yuan, X H; Qi, X W; Li, S J; Ye, X C

2014-06-18

After injury, inflammation, or degeneration, articular cartilage has limited self-repair ability. We aimed to explore the feasibility of repair of articular cartilage defects with tissue-engineered cartilage constructed by acellular cartilage matrices (ACMs) seeded with adipose-derived stem cells (ADSCs). The ADSCs were isolated from 3-month-old New Zealand albino rabbit by using collagenase and cultured and amplified in vitro. Fresh cartilage isolated from adult New Zealand albino rabbit were freeze-dried for 12 h and treated with Triton X-100, DNase, and RNase to obtain ACMs. ADSCs were seeded in the acellular cartilaginous matrix at 2x10(7)/mL, and cultured in chondrogenic differentiation medium for 2 weeks to construct tissue-engineered cartilage. Twenty-four New Zealand white rabbits were randomly divided into A, B, and C groups. Engineered cartilage was transplanted into cartilage defect position of rabbits in group A, group B obtained ACMs, and group C did not receive any transplants. The rabbits were sacrificed in week 12. The restored tissue was evaluated using macroscopy, histology, immunohistochemistry, and transmission electron microscopy (TEM). In the tissue-engineered cartilage group (group A), articular cartilage defects of the rabbits were filled with chondrocyte-like tissue with smooth surface. Immunohistochemistry showed type II-collagen expression and Alcian blue staining was positive. TEM showed chondrocytes in the recesses, with plenty of secretary matrix particles. In the scaffold group (group B), the defect was filled with fibrous tissue. No repaired tissue was found in the blank group (group C). Tissue-engineered cartilage using ACM seeded with ADSCs can help repair articular cartilage defects in rabbits.

[Repair of soft tissue defect in hand or foot with lobulated medial sural artery perforator flap].

Science.gov (United States)

Fengjing, Zhao; Jianmin, Yao; Xingqun, Zhang; Liang, Ma; Longchun, Zhang; Yibo, Xu; Peng, Wang; Zhen, Zhu

2015-11-01

To explore the clinical effect of the lobulated medial sural artery perforator flap in repairing soft tissue defect in hand or foot. Since March 2012 to September 2014, 6 cases with soft tissue defects in hands or feet were treated by lobulated medial sural artery flaps pedicled with 1st musculo-cutaneous perforator and 2st musculo-cutaneous perforator of the medial sural artery. The size of the flaps ranged from 4.5 cm x 10.0 cm to 6.0 cm x 17.0 cm. 5 cases of lobulated flap survived smoothly, only 1 lobulated flap had venous articulo, but this flap also survived after the articulo was removed by vascular exploration. All flaps had desirable appearance and sensation and the two-point discrimination was 6 mm in mean with 4 to 12 months follow-up (average, 7 months). Linear scar was left in donor sites in 3 cases and skin scar in 3 cases. There was no malfunction in donor sites. Lobulated medial sural artery perforator flap is feasible and ideal method for the treatment of soft tissue defect in hand or foot with satisfactory effect.

Treatment of large posttraumatic tibial bone defects using the Ilizarov method: a subjective outcome assessment.

Science.gov (United States)

Krappinger, Dietmar; Irenberger, Alexander; Zegg, Michael; Huber, Burkhart

2013-06-01

The treatment of large posttraumatic tibial bone defects using the Ilizarov method was shown to be successful in several studies. These studies, however, typically focus on the radiological and functional outcome using objective parameters only. The aim of the present study was therefore to assess the objective and subjective outcome of a consecutive series of patients with large posttraumatic tibial bone defects using the Ilizarov method. Additionally, it was our goal to assess the physical and mental stress for the patients and their relatives during the long treatment period and the general health status at final follow-up. A consecutive series of 15 patients with posttraumatic tibial bone defects of >30 mm after sustaining open tibial fractures and failure of internal fixation was included. The objective outcome was assessed at final follow-up using Paley's criteria. For the assessment of the subjective outcome, all patients were asked to evaluate their satisfaction with the function of the lower leg, the cosmetic appearance and overall outcome as well. The physical and mental stress of the treatment for the patients and the nearest relative of patients were assessed at the time of frame removal using a custom-made questionnaire. The SF-36 was used to evaluate the general health status at final follow-up. Solid bone union with stable soft tissue coverage and eradication of infection was achieved in all patients despite a high complication rate. The functional outcome at final follow-up was excellent or good in all patients. The patients' satisfaction with the overall outcome and the function of the lower extremity was high as well. The fear of amputation and complications was the major subjective burden for both the patients and their relatives. The long external fixation time is another relevant issue. The Ilizarov method is a safe option for the treatment of large posttraumatic tibial bone defects after failure of internal fixation despite the high

Treatment of open tibial shaft fracture with soft tissue and bone defect caused by aircraft bomb--case report.

Science.gov (United States)

Golubović, Zoran; Vidić, Goran; Trenkić, Srbobran; Vukasinović, Zoran; Lesić, Aleksandar; Stojiljković, Predrag; Stevanović, Goran; Golubović, Ivan; Visnjić, Aleksandar; Najman, Stevo

2010-01-01

Aircraft bombs can cause severe orthopaedic injuries. Tibia shaft fractures caused by aircraft bombs are mostly comminuted and followed by bone defects, which makes the healing process extremely difficult and prone to numerous complications. The goal of this paper is to present the method of treatment and the end results of treatment of a serious open tibial fracture with soft and bone tissue defects resulting from aircraft bomb shrapnel wounds. A 26-year-old patient presented with a tibial fracture as the result of a cluster bomb shrapnel wound. He was treated applying the method of external bone fixation done two days after wounding, as well as of early coverage of the lower leg soft tissue defects done on the tenth day after the external fixation of the fracture. The external fixator was removed after five months, whereas the treatment was continued by means of functional plaster cast for another two months. The final functional result was good. Radical wound debridement, external bone fixation of the fracture, and early reconstruction of any soft tissue and bone defects are the main elements of the treatment of serious fractures.

Implantation of tetrapod-shaped granular artificial bones or β-tricalcium phosphate granules in a canine large bone-defect model.

Science.gov (United States)

Choi, Sungjin; Liu, I-Li; Yamamoto, Kenichi; Honnami, Muneki; Sakai, Takamasa; Ohba, Shinsuke; Echigo, Ryosuke; Suzuki, Shigeki; Nishimura, Ryouhei; Chung, Ung-Il; Sasaki, Nobuo; Mochizuki, Manabu

2014-03-01

We investigated biodegradability and new bone formation after implantation of tetrapod-shaped granular artificial bone (Tetrabone®) or β-tricalcium phosphate granules (β-TCP) in experimental critical-size defects in dogs, which were created through medial and lateral femoral condyles. The defect was packed with Tetrabone® (Tetrabone group) or β-TCP (β-TCP group) or received no implant (control group). Computed tomography (CT) was performed at 0, 4 and 8 weeks after implantation. Micro-CT and histological analysis were conducted to measure the non-osseous tissue rate and the area and distribution of new bone tissue in the defect at 8 weeks after implantation. On CT, β-TCP was gradually resorbed, while Tetrabone® showed minimal resorption at 8 weeks after implantation. On micro-CT, non-osseous tissue rate of the control group was significantly higher compared with the β-TCP and Tetrabone groups (Pbone tissue of the β-TCP group was significantly greater than those of the Tetrabone and control groups (Pbone distribution of the Tetrabone group was significantly greater than those of the β-TCP and control groups (Pbone defects in dogs.

Free temporal fascia flap to cover soft tissue defects of the foot: a case report

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Schreiber, Martin

2015-01-01

Full Text Available Severe soft tissue defects as a result of lye contamination remain a huge challenge in the interdisciplinary approach of trauma surgeons and plastic surgeons. Free tissue transfer is a suitable surgical option for successful reconstruction of form and function of defects in the distal parts of the lower extremities. We report the successful two-stage reconstruction of a full thickness lye contamination at the dorsum of the foot with a free temporoparietal fascia flap covered with a split-thickness skin graft from the thigh. The described method is a suitable operative alternative to anterolateral thigh flaps or other thin fascia flaps regarding flap harvest and donor site morbidity and should be considered in the portfolio of the plastic surgeon.

Prognostic significance of large perfusion defects on thallium-201 myocardial scintigraphy in dilated cardiomyopathy

International Nuclear Information System (INIS)

Takata, Jun; Doi, Yoshinori; Chikamori, Taishiro; Yonezawa, Yoshihiro; Hamashige, Naohisa; Kuzume, Osamu; Ozawa, Toshio

1989-01-01

To evaluate the prognostic significance of perfusion abnormalities, particularly large defects, in dilated cardiomyopathy (DCM), we performed thallium-201 myocardial scintigraphy and 24-hour ambulatory ECG monitoring in 27 patients. The abnormal scintigraphic patterns and the presence of ventricular tachycardia (VT) were correlated with causes of death during a follow-up period of 30.0±19.4 months. Eight patients had large defects (LD), 11 had multiple small defects (MSD), and eight had no defects (NL). The patients with LD had extensive ventricular akinesis in the region of the perfusion defect, significantly elevated LVEDP (LD 20.6±7.4 mmHg, MSD 15.5±7.6 mmHg, NL 10.3±2.3 mmHg: LD vs NL; p<0.01, MSD vs NL; p<0.05), and reduced ejection fraction (LD 23.9±9.1%, MSD 32.7±7.2%, NL 40.3±7.7%: LD vs MSD; p<0.05, MSD vs NL; p<0.01). VT was detected in 11 patients; among whom three had LD, six had MSD, and two had no defects. Among seven patients who died during follow-up (five of heart failure, one sudden death, and one non-cardiac death), five had LD and two had MSD. There were no deaths among patients without defects. Among 11 patients with VT, only one died suddenly. In conclusion, large scintigraphic defects correlated well with severe LV dysfunction, and this is an important variable in predicting outcomes in DCM. (author)

Development of large engineered cartilage constructs from a small population of cells.

Science.gov (United States)

Brenner, Jillian M; Kunz, Manuela; Tse, Man Yat; Winterborn, Andrew; Bardana, Davide D; Pang, Stephen C; Waldman, Stephen D

2013-01-01

Confronted with articular cartilage's limited capacity for self-repair, joint resurfacing techniques offer an attractive treatment for damaged or diseased tissue. Although tissue engineered cartilage constructs can be created, a substantial number of cells are required to generate sufficient quantities of tissue for the repair of large defects. As routine cell expansion methods tend to elicit negative effects on chondrocyte function, we have developed an approach to generate phenotypically stable, large-sized engineered constructs (≥3 cm(2) ) directly from a small amount of donor tissue or cells (as little as 20,000 cells to generate a 3 cm(2) tissue construct). Using rabbit donor tissue, the bioreactor-cultivated constructs were hyaline-like in appearance and possessed a biochemical composition similar to native articular cartilage. Longer bioreactor cultivation times resulted in increased matrix deposition and improved mechanical properties determined over a 4 week period. Additionally, as the anatomy of the joint will need to be taken in account to effectively resurface large affected areas, we have also explored the possibility of generating constructs matched to the shape and surface geometry of a defect site through the use of rapid-prototyped defect tissue culture molds. Similar hyaline-like tissue constructs were developed that also possessed a high degree of shape correlation to the original defect mold. Future studies will be aimed at determining the effectiveness of this approach to the repair of cartilage defects in an animal model and the creation of large-sized osteochondral constructs. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

A large-scale molecular dynamics study of the divacancy defect in graphene

International Nuclear Information System (INIS)

Leyssale, Jean-Marc; Vignoles, Gerard L.

2014-01-01

We report on the dynamical behavior of single divacancy defects in large graphene sheets as studied by extensive classical molecular dynamics (MD) simulations at high temperatures and static calculations. In the first part of the paper, the ability of the used interatomic potential to properly render the stability and dynamics (energy barriers) of such defects is validated against electronic structure calculations from the literature. Then, results from MD simulations are presented. In agreement with recent TEM studies, some mobility is observed through a series of Stone-Wales-like bond rotations involving the 5-8-5, 555-777, and 5555-6-7777 reconstructions. Although these three structures are by far the most probable structures of the DV defect, not less than 18 other full reconstructions, including the experimentally observed 55-66-77 defect, were occasionally observed in the ∼1.5 μs of MD trajectories analyzed in this work. Most of these additional reconstructions have moderate formation energies and can be formed by a bond rotation mechanism from one of the aforementioned structures, with a lower activation energy than the one required to form a Stone-Wales defect in graphene. Therefore their future experimental observation is highly probable. The results presented here also suggest that the barrier to a conventional Stone-Wales transformation (the formation of two pentagon/heptagon pairs from four hexagons) can be significantly reduced in the vicinity of an existing defect, strengthening a recently proposed melting mechanism for graphene based on the aggregation of Stone-Wales defects. From a structural point of view, in addition to pentagons, heptagons, and octagons, these new DV reconstructions can also contain four- and nine-member rings and show a particularly large spatial extent of up to 13 rings (42 atoms) against three (14 atoms) for the original 5-8-5 defect. (authors)

Cell density signal protein suitable for treatment of connective tissue injuries and defects

Science.gov (United States)

Schwarz, Richard I.

2002-08-13

Identification, isolation and partial sequencing of a cell density protein produced by fibroblastic cells. The cell density signal protein comprising a 14 amino acid peptide or a fragment, variant, mutant or analog thereof, the deduced cDNA sequence from the 14 amino acid peptide, a recombinant protein, protein and peptide-specific antibodies, and the use of the peptide and peptide-specific antibodies as therapeutic agents for regulation of cell differentiation and proliferation. A method for treatment and repair of connective tissue and tendon injuries, collagen deficiency, and connective tissue defects.

A large ventricular septal defect complicating resuscitation after blunt trauma

Directory of Open Access Journals (Sweden)

Henry D I De′Ath

2012-01-01

Full Text Available A young adult pedestrian was admitted to hospital after being hit by a car. On arrival to the Accident and Emergency Department, the patient was tachycardic, hypotensive, hypoxic, and acidotic with a Glasgow Coma Scale of 3. Despite initial interventions, the patient remained persistently hypotensive. An echocardiogram demonstrated a traumatic ventricular septal defect (VSD with right ventricular strain and increased pulmonary artery pressure. Following a period of stabilization, open cardiothoracic surgery was performed and revealed an aneurysmal septum with a single large defect. This was repaired with a bovine patch, resulting in normalization of right ventricular function. This case provides a vivid depiction of a large VSD in a patient following blunt chest trauma with hemodynamic compromise. In all thoracic trauma patients, and particularly those poorly responsive to resuscitation, VSDs should be considered. Relevant investigations and management strategies are discussed.

Biomaterials with antibacterial and osteoinductive properties to repair infected bone defects

NARCIS (Netherlands)

Lu, H.; Liu, Y.; Guo, J.; Wu, H.; Wang, J.; Wu, G.

2016-01-01

The repair of infected bone defects is still challenging in the fields of orthopedics, oral implantology and maxillofacial surgery. In these cases, the self-healing capacity of bone tissue can be significantly compromised by the large size of bone defects and the potential/active bacterial activity.

Ad hoc posterior tibial vessels perforator propeller flaps for the reconstruction of lower third leg soft- tissue defects

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Thalaivirithan Margabandu Balakrishnan

2017-01-01

Full Text Available Introduction: Lower third leg soft tissue defects with anatomical and pathological constraints are posing formidable challenges to reconstructive surgeon. Aim: This retrospective study was conducted to assess the effectiveness of ad hoc posterior tibial vessels perforator-propeller flaps for the reconstruction of small and medium sized soft tissue defects in the lower third leg. Patients and Methods: 22 patients (16 were males and 6 were females were involved in this study between period of January 2012 and December 2016.We followed the protocol of initial non delineating exploratory incision made to find out single best perforator in all patients. All the defects in leg reconstructed with adhoc posterior tibial vessel propeller flaps. Results: All 22 flaps survived well. All in an average of 13 months follow up period, had pain free walking, with minimal scarring and acceptable aesthesis at the reconstruction sites with no need for any secondary procedure. Conclusion: With inability of preoperatively dopplering the perforators in the lower third leg region, the exploratory posterior nondelineating incision was used in all cases to secure the single best perforator for the propeller flaps. Thus adhoc posterior tibial vessel propeller flaps are dependable, easily adoptable for the reconstruction of soft tissue defects of the lower third leg region.

Bone tissue ultrastructural defects in a mouse model for osteogenesis imperfecta: a Raman spectroscopy study

Science.gov (United States)

Chen, Tsoching; Kozloff, Kenneth M.; Goldstein, Steven A.; Morris, Michael D.

2004-07-01

Osteogenesis imperfecta (OI) is genetic defect in which the genes that code for the α1(I) or α2(I) chains of type I collagen are defective. The defects often result in substitution of a bulky amino acid for glycine, causing formation of collagen that can not form the normal triple helix. Depending on the details of the defects, the outcomes range from controllable to lethal. This study focuses on OI type IV, a more common and moderately severe form of the disease. People with the disease have a substantial increase in the risk and rate of fracture. We examine the spectroscopic consequences of these defects, using a mouse model (BRTL) that mimics OI type IV. We compare Raman images from tibial cortical tissue of wild-type mice and BRTL mice with single copy of mutation and show that both mineral to matrix ratios and collagen inter-fibril cross-links are different in wild-type and mutant mice.

Immediate Reconstruction of a Soft-Tissue Defect in a Burn Patient whit a Peroforator-Based Propeller Flap: A Case Report

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Burhan Özalp

2017-06-01

Full Text Available Soft tissue reconstruction of the distal lower leg is a challenging issue for plastic surgeons. Immediate coverage of exposed anatomical structures with soft tissue after trauma prevents these structures from being infected, and this is very important for burn patients. Free flaps have recently been accepted as the gold-standard technique for ankle and foot reconstruction; however, this is changing with the increasing popularity of the perforator flaps. Today, perforator flaps are commonly performed for the reconstruction of the soft-tissue defects across the body. In this report, we want to present the reconstruction of a soft-tissue defect case using perforator-based propeller flap in a burn patient for immediate reconstruction. A 45-year-old male patient had a soft-tissue defect over the medial side of the ankle and foot due to a high-voltage electrical burn. The exposed bone tissue was covered with a propeller flap of 15×6 cm size, without any circulation problems during the postoperative period. In conclusion, we want to state that perforator-based propeller flaps are reliable, successful, and effective techniques for the immediate reconstruction of distal leg and foot. These flaps can be easily performed without requiring any microsurgical technique thus, they can be commonly performed by most of the plastic surgeons.

The Axolotl Fibula as a Model for the Induction of Regeneration across Large Segment Defects in Long Bones of the Extremities

Science.gov (United States)

Chen, Xiaoping; Song, Fengyu; Jhamb, Deepali; Li, Jiliang; Bottino, Marco C.; Palakal, Mathew J.; Stocum, David L.

2015-01-01

We tested the ability of the axolotl (Ambystoma mexicanum) fibula to regenerate across segment defects of different size in the absence of intervention or after implant of a unique 8-braid pig small intestine submucosa (SIS) scaffold, with or without incorporated growth factor combinations or tissue protein extract. Fractures and defects of 10% and 20% of the total limb length regenerated well without any intervention, but 40% and 50% defects failed to regenerate after either simple removal of bone or implanting SIS scaffold alone. By contrast, scaffold soaked in the growth factor combination BMP-4/HGF or in protein extract of intact limb tissue promoted partial or extensive induction of cartilage and bone across 50% segment defects in 30%-33% of cases. These results show that BMP-4/HGF and intact tissue protein extract can promote the events required to induce cartilage and bone formation across a segment defect larger than critical size and that the long bones of axolotl limbs are an inexpensive model to screen soluble factors and natural and synthetic scaffolds for their efficacy in stimulating this process. PMID:26098852

Different healing process of esophageal large mucosal defects by endoscopic mucosal dissection between with and without steroid injection in an animal model.

Science.gov (United States)

Nonaka, Kouichi; Miyazawa, Mitsuo; Ban, Shinichi; Aikawa, Masayasu; Akimoto, Naoe; Koyama, Isamu; Kita, Hiroto

2013-04-25

Stricture formation is one of the major complications after endoscopic removal of large superficial squamous cell neoplasms of the esophagus, and local steroid injections have been adopted to prevent it. However, fundamental pathological alterations related to them have not been well analyzed so far. The aim of this study was to analyze the time course of the healing process of esophageal large mucosal defects resulting in stricture formation and its modification by local steroid injection, using an animal model. Esophageal circumferential mucosal defects were created by endoscopic mucosal dissection (ESD) for four pigs. One pig was sacrificed five minutes after the ESD, and other two pigs were followed-up on endoscopy and sacrificed at the time of one week and three weeks after the ESD, respectively. The remaining one pig was followed-up on endoscopy with five times of local steroid injection and sacrificed at the time of eight weeks after the ESD. The esophageal tissues of all pigs were subjected to pathological analyses. For the pigs without steroid injection, the esophageal stricture was completed around three weeks after the ESD on both endoscopy and esophagography. Histopathological examination of the esophageal tissues revealed that spindle-shaped α-smooth muscle actin (SMA)-positive myofibroblasts arranged in a parallel fashion and extending horizontally were identified at the ulcer bed one week after the ESD, and increased contributing to formation of the stenotic luminal ridge covered with the regenerated epithelium three weeks after the ESD. The proper muscle layer of the stricture site was thinned with some myocytes which seemingly showed transition to the myofibroblast layer. By contrast, for the pig with steroid injection, esophageal stricture formation was not evident with limited appearance of the spindle-shaped myofibroblasts, instead, appearance of stellate or polygocal SMA-positive stromal cells arranged haphazardly in the persistent granulation

In silico Mechano-Chemical Model of Bone Healing for the Regeneration of Critical Defects: The Effect of BMP-2.

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Frederico O Ribeiro

Full Text Available The healing of bone defects is a challenge for both tissue engineering and modern orthopaedics. This problem has been addressed through the study of scaffold constructs combined with mechanoregulatory theories, disregarding the influence of chemical factors and their respective delivery devices. Of the chemical factors involved in the bone healing process, bone morphogenetic protein-2 (BMP-2 has been identified as one of the most powerful osteoinductive proteins. The aim of this work is to develop and validate a mechano-chemical regulatory model to study the effect of BMP-2 on the healing of large bone defects in silico. We first collected a range of quantitative experimental data from the literature concerning the effects of BMP-2 on cellular activity, specifically proliferation, migration, differentiation, maturation and extracellular matrix production. These data were then used to define a model governed by mechano-chemical stimuli to simulate the healing of large bone defects under the following conditions: natural healing, an empty hydrogel implanted in the defect and a hydrogel soaked with BMP-2 implanted in the defect. For the latter condition, successful defect healing was predicted, in agreement with previous in vivo experiments. Further in vivo comparisons showed the potential of the model, which accurately predicted bone tissue formation during healing, bone tissue distribution across the defect and the quantity of bone inside the defect. The proposed mechano-chemical model also estimated the effect of BMP-2 on cells and the evolution of healing in large bone defects. This novel in silico tool provides valuable insight for bone tissue regeneration strategies.

Novel Therapy for Bone Regeneration in Large Segmental Defects

Science.gov (United States)

2017-12-01

Nanohydrox- yapatite- coated electrospun poly(L-lactide) nanofibers enhance osteogenic differentiation of stem cells and induce ectopic bone formation... Bone Regeneration in a Large Animal Critical Sized Defect Model, Second Annual Symposium on Cell Therapy and Regenerative Medicine, 2016 4...osteogenic cells and growth factors demonstrated success in facilitating bone regeneration in these cases. However, due to the lack of mechanical property

Endoscopic Approach for Tissue Expansion for Different Cosmetic ...

African Journals Online (AJOL)

Background/Purpose: The use of tissue expanders in plastic and reconstruction surgery is now well established for large defects in adults & children. Tissue expansion is one of the reconstructive surgeon's alternatives in providing optimal tissue replacement when skin shortage is a major problem. Predesigned plan about ...

One-stage reconstruction of soft tissue defects with the sandwich technique: Collagen-elastin dermal template and skin grafts

Directory of Open Access Journals (Sweden)

Uwe Wollina

2011-01-01

Full Text Available Background : A full-thickness soft tissue defect closure often needs complex procedures. The use of dermal templates can be helpful in improving the outcome. Objective : The objective was to evaluate a sandwich technique combining the dermal collagen-elastin matrix with skin grafts in a one-stage procedure. Materials and Methods : Twenty-three patients with 27 wounds were enrolled in this prospective single-centre observational study. The mean age was 74.8 ± 17.2 years. Included were full-thickness defects with exposed bone, cartilage and/ or tendons. The dermal collagen-elastin matrix was applied onto the wound bed accomplished by skin transplants, i.e. ′sandwich′ transplantation. In six wounds, the transplants were treated with intermittent negative pressure therapy. Results : The size of defects was ≤875 cm 2 . The use of the dermal template resulted in a complete and stable granulation in 100% of wounds. Seventeen defects showed a complete closure and 19 achieved a complete granulation with an incomplete closure. There was a marked pain relief. No adverse events were noted due to the dermal template usage. Conclusions : Sandwich transplantation with the collagen-elastin matrix is a useful tool when dealing with full-thickness soft tissue defects with exposed bone, cartilage or tendons.

The Axolotl Fibula as a Model for the Induction of Regeneration across Large Segment Defects in Long Bones of the Extremities.

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Xiaoping Chen

Full Text Available We tested the ability of the axolotl (Ambystoma mexicanum fibula to regenerate across segment defects of different size in the absence of intervention or after implant of a unique 8-braid pig small intestine submucosa (SIS scaffold, with or without incorporated growth factor combinations or tissue protein extract. Fractures and defects of 10% and 20% of the total limb length regenerated well without any intervention, but 40% and 50% defects failed to regenerate after either simple removal of bone or implanting SIS scaffold alone. By contrast, scaffold soaked in the growth factor combination BMP-4/HGF or in protein extract of intact limb tissue promoted partial or extensive induction of cartilage and bone across 50% segment defects in 30%-33% of cases. These results show that BMP-4/HGF and intact tissue protein extract can promote the events required to induce cartilage and bone formation across a segment defect larger than critical size and that the long bones of axolotl limbs are an inexpensive model to screen soluble factors and natural and synthetic scaffolds for their efficacy in stimulating this process.

Biomaterials with Antibacterial and Osteoinductive Properties to Repair Infected Bone Defects

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Lu, Haiping; Liu, Yi; Guo, Jing; Wu, Huiling; Wang, Jingxiao; Wu, Gang

2016-01-01

The repair of infected bone defects is still challenging in the fields of orthopedics, oral implantology and maxillofacial surgery. In these cases, the self-healing capacity of bone tissue can be significantly compromised by the large size of bone defects and the potential/active bacterial activity. Infected bone defects are conventionally treated by a systemic/local administration of antibiotics to control infection and a subsequent implantation of bone grafts, such as autografts and allogra...

Microsurgical reconstruction of large nerve defects using autologous nerve grafts.

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Daoutis, N K; Gerostathopoulos, N E; Efstathopoulos, D G; Misitizis, D P; Bouchlis, G N; Anagnostou, S K

1994-01-01

Between 1986 and 1993, 643 patients with peripheral nerve trauma were treated in our clinic. Primary neurorraphy was performed in 431 of these patients and nerve grafting in 212 patients. We present the functional results after nerve grafting in 93 patients with large nerve defects who were followed for more than 2 years. Evaluation of function was based on the Medical Research Council (MRC) classification for motor and sensory recovery. Factors affecting functional outcome, such as age of the patient, denervation time, length of the defect, and level of the injury were noted. Good results according to the MRC classification were obtained in the majority of cases, although function remained less than that of the uninjured side.

Surgical membranes as directional delivery devices to generate tissue: testing in an ovine critical sized defect model.

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Melissa L Knothe Tate

Full Text Available Pluripotent cells residing in the periosteum, a bi-layered membrane enveloping all bones, exhibit a remarkable regenerative capacity to fill in critical sized defects of the ovine femur within two weeks of treatment. Harnessing the regenerative power of the periosteum appears to be limited only by the amount of healthy periosteum available. Here we use a substitute periosteum, a delivery device cum implant, to test the hypothesis that directional delivery of endogenous periosteal factors enhances bone defect healing.Newly adapted surgical protocols were used to create critical sized, middiaphyseal femur defects in four groups of five skeletally mature Swiss alpine sheep. Each group was treated using a periosteum substitute for the controlled addition of periosteal factors including the presence of collagen in the periosteum (Group 1, periosteum derived cells (Group 2, and autogenic periosteal strips (Group 3. Control group animals were treated with an isotropic elastomer membrane alone. We hypothesized that periosteal substitute membranes incorporating the most periosteal factors would show superior defect infilling compared to substitute membranes integrating fewer factors (i.e. Group 3>Group 2>Group 1>Control.Based on micro-computed tomography data, bone defects enveloped by substitute periosteum enabling directional delivery of periosteal factors exhibit superior bony bridging compared to those sheathed with isotropic membrane controls (Group 3>Group 2>Group 1, Control. Quantitative histological analysis shows significantly increased de novo tissue generation with delivery of periosteal factors, compared to the substitute periosteum containing a collagen membrane alone (Group 1 as well as compared to the isotropic control membrane. Greatest tissue generation and maximal defect bridging was observed when autologous periosteal transplant strips were included in the periosteum substitute.Periosteum-derived cells as well as other factors

Periodontal tissue reaction to customized nano-hydroxyapatite block scaffold in one-wall intrabony defect: a histologic study in dogs.

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Lee, Jung-Seok; Park, Weon-Yeong; Cha, Jae-Kook; Jung, Ui-Won; Kim, Chang-Sung; Lee, Yong-Keun; Choi, Seong-Ho

2012-04-01

This study evaluated histologically the tissue responses to and the effects of a customized nano-hydroxyapatite (n-HA) block bone graft on periodontal regeneration in a one-wall periodontal-defect model. A customized block bone for filling in the standardized periodontal defect was fabricated from prefabricated n-HA powders and a polymeric sponge. Bilateral 4×4×5 mm (buccolingual width×mesiodistal width×depth), one-wall, critical-size intrabony periodontal defects were surgically created at the mandibular second and fourth premolars of five Beagle dogs. In each dog, one defect was filled with block-type HA and the other served as a sham-surgery control. The animals were sacrificed following an 8-week healing interval for clinical and histological evaluations. Although the sites that received an n-HA block showed minimal bone formation, the n-HA block was maintained within the defect with its original hexahedral shape. In addition, only a limited inflammatory reaction was observed at sites that received an n-HA block, which might have been due to the high stability of the customized block bone. In the limitation of this study, customized n-HA block could provide a space for periodontal tissue engineering, with minimal inflammation.

[Pedicle flap transfer combined with external fixator to treat leg open fracture with soft tissue defect].

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Luo, Zhongchun; Lou, Hua; Jiang, Junwei; Song, Chunlin; Gong, Min; Wang, Yongcai

2008-08-01

To investigate the clinical results of treating leg open fracture with soft tissue defect by pedicle flap transfer in combination with external fixator. From May 2004 to June 2007, 12 cases of leg open fracture with soft tissue defect, 9 males and 3 females aged 18-75 years, were treated. Among them, 8 cases were caused by traffic accidents, 2 crush, 1 falling and 1 mechanical accident. According to the Gustilo Classification, there were 2 cases of type II, 5 of type IIIA and 5 of type IIIB. There were 2 cases of upper-tibia fracture, 3 of middle-tibia and 7 of middle-lower. The sizes of soft tissue defect ranged from 5 cm x 3 cm to 22 cm x 10 cm.The sizes of exposed bone ranged from 3 cm x 2 cm to 6 cm x 3 cm. The course of the disease was 1-12 hours. Fracture fixation was reached by external fixators or external fixators and limited internal fixation with Kirschner wire. The wounds with exposed tendons and bones were repaired by ipsilateral local rotation flap, sural neurocutaneous flap and saphenous nerve flap. The size of selected flap ranged from 5 cm x 4 cm to 18 cm x 12 cm. Granulation wounds were repaired by skin grafting or direct suture. All patients were followed up for 6 months to 2 years. All patients survived, among whom 2 with the wound edge infection and 1 with the distal necrosis were cured by changing the dressing, 8 with pin hole infection were treated by taking out the external fixator, 1 with nonunion received fracture healing after bone graft in comminuted fracture of lower tibia, 2 suffered delayed union in middle-lower tibia fracture. The ROM of ankle in 3 cases was mildly poor with surpass-joint fixation, with plantar extension of 0-10 degrees and plantar flexion of 10-30 degrees, while the others had plantar extension of 10-20 degrees and plantar flexion of 30-50 degrees. The method of pedicle flap transfer combined with external fixator is safe and effective for the leg open fracture with soft tissue defect.

Composite tissue allotransplantation : functional, immunological and ethical aspects

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Vossen, M.; Brouha, P.C.R.

2007-01-01

Composite tissue allotransplantation (CTA) is a new therapeutic modality to reconstruct large tissue defects of the face, larynx, and extremities. The research in this thesis focuses on various aspects of CTA, i.e. 1) immunosuppression regimens and their influence on bone quality, 2) induction of

An Osteoconductive, Osteoinductive, and Osteogenic Tissue-Engineered Product for Trauma and Orthopaedic Surgery: How Far Are We?

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Wasim S. Khan

2012-01-01

Full Text Available The management of large bone defects due to trauma, degenerative disease, congenital deformities, and tumor resection remains a complex issue for the orthopaedic reconstructive surgeons. The requirement is for an ideal bone replacement which is osteoconductive, osteoinductive, and osteogenic. Autologous bone grafts are still considered the gold standard for reconstruction of bone defects, but donor site morbidity and size limitations are major concern. The use of bioartificial bone tissues may help to overcome these problems. The reconstruction of large volume defects remains a challenge despite the success of reconstruction of small-to-moderate-sized bone defects using engineered bone tissues. The aim of this paper is to understand the principles of tissue engineering of bone and its clinical applications in reconstructive surgery.

An osteoconductive, osteoinductive, and osteogenic tissue-engineered product for trauma and orthopaedic surgery: how far are we?

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Khan, Wasim S; Rayan, Faizal; Dhinsa, Baljinder S; Marsh, David

2012-01-01

The management of large bone defects due to trauma, degenerative disease, congenital deformities, and tumor resection remains a complex issue for the orthopaedic reconstructive surgeons. The requirement is for an ideal bone replacement which is osteoconductive, osteoinductive, and osteogenic. Autologous bone grafts are still considered the gold standard for reconstruction of bone defects, but donor site morbidity and size limitations are major concern. The use of bioartificial bone tissues may help to overcome these problems. The reconstruction of large volume defects remains a challenge despite the success of reconstruction of small-to-moderate-sized bone defects using engineered bone tissues. The aim of this paper is to understand the principles of tissue engineering of bone and its clinical applications in reconstructive surgery.

Treatment of soft-tissue loss with nerve defect in the finger using the boomerang nerve flap.

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Chen, Chao; Tang, Peifu; Zhang, Xu

2013-01-01

This study reports simultaneous repair of soft-tissue loss and proper digital nerve defect in the finger using a boomerang nerve flap including nerve graft from the dorsal branch of the proper digital nerve. From July of 2007 to May of 2010, the flap was used in 17 fingers in 17 patients. The injured fingers included five index, seven long, and five ring fingers. The mean soft-tissue loss was 2.5 × 1.9 cm. The mean flap size was 2.8 × 2.1 cm. Proper digital nerve defects were reconstructed using nerve graft harvested from the dorsal branch of the adjacent finger's proper digital nerve. The average nerve graft length was 2.5 cm. The comparison group included 32 patients treated using a cross-finger flap and a secondary free nerve graft. In the study group, 15 flaps survived completely. Partial necrosis at the distal edge of the flap occurred in two cases. At a mean follow-up of 22 months, the average static two-point discrimination and Semmes-Weinstein monofilament test results on the pulp of the reconstructed finger were 7.5 mm and 3.86, respectively. In the comparison group, the results were 9.3 mm and 3.91, respectively. The study group presented better discriminatory sensation on the pulp and milder pain and cold intolerance in the reconstructed finger. The boomerang nerve flap is useful and reliable for reconstructing complicated finger damage involving soft-tissue loss and nerve defect, especially in difficult anatomical regions. Therapeutic, II.

Histomorphometric Analysis of Periodontal Tissue Regeneration by the Use of High Density Polytetrafluoroethylen Membrane in Grade II Furcation Defects of Dogs

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Raoofi S

2015-09-01

Full Text Available Statement of Problem: There are limited histomorphometric studies on biologic efficacy of high density tetrafluoroethylen (d-PTFE membrane. Objectives: To investigate the healing of surgically induced grade II furcation defects in dogs following the use of dense polytetrafluoroethylene as the barrier membrane and to compare the results with the contra lateral control teeth without the application of any membrane. Materials andMethods: Mandibular and maxillary 3rd premolar teeth of 18 young adult male mongrel dogs were used for the experiment. The furcation defects were created during the surgery. 5 weeks later, regenerative surgery was performed. The third premolar teeth were assigned randomly to control and test groups. In the test group, after a full thickness flap reflection, the d-PTFE membrane was placed over furcation defects. In the control group, no membrane was placed over the defect. 37 tissue blocks containing the teeth and surrounding hard and soft tissues were obtained three months post-regenerative surgery. The specimens were demineralized, serially sectioned, mounted and stained with Hematoxylin and Eosin staining technique. From each tissue block, 35-45 sections of 10 μm thickness within 60μm interval captured the entire surgically created defect. The histological images were transferred to computer and then the linear measurement ranges of the defects area, interadicular alveolar bone, epithelial attachment and coronal extension of the new cementum were done. Then, the volume and area of aforementioned parameters were calculated considering the thickness and interval of the sections. To compare the parameters between the control and test teeth, we calculated the amount of each one proportionally to the original amount of defects. Results: The mean interradicular root surface areas of original defects covered with new cementum was 74.46% and 29.59% for the membrane and control defects, respectively (p < 0.0001. Corresponding

Mutation of p107 exacerbates the consequences of Rb loss in embryonic tissues and causes cardiac and blood vessel defects.

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Berman, Seth D; West, Julie C; Danielian, Paul S; Caron, Alicia M; Stone, James R; Lees, Jacqueline A

2009-09-01

The retinoblastoma tumor-suppressor protein, pRb, is a member of the pocket protein family that includes p107 and p130. These proteins have well-defined roles in regulating entry into and exit from the cell cycle and also have cell cycle-independent roles in facilitating differentiation. Here we investigate the overlap between pocket protein's function during embryonic development by using conditional mutant alleles to generate Rb;p107 double-mutant embryos (DKOs) that develop in the absence of placental defects. These DKOs die between e13.5 and e14.5, much earlier than either the conditional Rb or the germline p107 single mutants, which survive to birth or are largely viable, respectively. Analyses of the e13.5 DKOs shows that p107 mutation exacerbates the phenotypes resulting from pRb loss in the central nervous system and lens, but not in the peripheral nervous system. In addition, these embryos exhibit novel phenotypes, including increased proliferation of blood vessel endothelial cells, and heart defects, including double-outlet right ventricle (DORV). The DORV is caused, at least in part, by a defect in blood vessel endothelial cells and/or heart mesenchymal cells. These findings demonstrate novel, overlapping functions for pRb and p107 in numerous murine tissues.

Guided tissue regeneration for periodontal infra-bony defects.

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Needleman, I G; Worthington, H V; Giedrys-Leeper, E; Tucker, R J

2006-04-19

Conventional treatment of destructive periodontal (gum) disease arrests the disease but does not usually regain the bone support or connective tissue lost in the disease process. Guided tissue regeneration (GTR) is a surgical procedure that specifically aims to regenerate the periodontal tissues when the disease is advanced and could overcome some of the limitations of conventional therapy. To assess the efficacy of GTR in the treatment of periodontal infra-bony defects measured against conventional surgery (open flap debridement (OFD)) and factors affecting outcomes. We conducted an electronic search of the Cochrane Oral Health Group Trials Register, MEDLINE and EMBASE up to April 2004. Handsearching included Journal of Periodontology, Journal of Clinical Periodontology, Journal of Periodontal Research and bibliographies of all relevant papers and review articles up to April 2004. In addition, we contacted experts/groups/companies involved in surgical research to find other trials or unpublished material or to clarify ambiguous or missing data and posted requests for data on two periodontal electronic discussion groups. Randomised, controlled trials (RCTs) of at least 12 months duration comparing guided tissue regeneration (with or without graft materials) with open flap debridement for the treatment of periodontal infra-bony defects. Furcation involvements and studies specifically treating aggressive periodontitis were excluded. Screening of possible studies and data extraction was conducted independently. The methodological quality of studies was assessed in duplicate using individual components and agreement determined by Kappa scores. Methodological quality was used in sensitivity analyses to test the robustness of the conclusions. The Cochrane Oral Health Group statistical guidelines were followed and the results expressed as mean differences (MD and 95% CI) for continuous outcomes and risk ratios (RR and 95% CI) for dichotomous outcomes calculated using

Repair of large frontal temporal parietal skull defect with digitally reconstructed titanium mesh: a report of 20 cases

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Gang-ge CHENG

2013-09-01

Full Text Available Objective　To explore the clinical effect and surgical technique of the repair of large defect involving frontal, temporal, and parietal regions using digitally reconstructed titanium mesh. Methods　Twenty patients with large frontal, temporal, and parietal skull defect hospitalized in Air Force General Hospital from November 2006 to May 2012 were involved in this study. In these 20 patients, there were 13 males and 7 females, aged 18-58 years (mean 39 years, and the defect size measured from 7.0cm×9.0cm to 11.5cm×14.0cm (mean 8.5cm×12.0cm. Spiral CT head scan and digital three-dimensional reconstruction of skull were performed in all the patients. The shape and geometric size of skull defect was traced based on the symmetry principle, and then the data were transferred into digital precision lathe to reconstruct a titanium mesh slightly larger (1.0-1.5cm than the skull defect, and the finally the prosthesis was perfected after pruning the border. Cranioplasty was performed 6-12 months after craniotomy using the digitally reconstructed titanium mesh. Results　The digitally reconstructed titanium mesh was used in 20 patients with large frontal, temporal, parietal skull defect. The surgical technique was relatively simple, and the surgical duration was shorter than before. The titanium mesh fit to the defect of skull accurately with satisfactory molding effect, good appearance and symmetrical in shape. No related complication was found in all the patients. Conclusion　Repair of large frontal, temporal, parietal skull defect with digitally reconstructed titanium mesh is more advantageous than traditional manual reconstruction, and it can improve the life quality of patients.

Surgical Management of Large Periorbital Cutaneous Defects: Aesthetic Considerations and Technique Refinements.

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Zou, Yun; Hu, Li; Tremp, Mathias; Jin, Yunbo; Chen, Hui; Ma, Gang; Lin, Xiaoxi

2018-02-23

The aim of this study was to repair large periorbital cutaneous defects by an innovative technique called PEPSI (periorbital elevation and positioning with secret incisions) technique with functional and aesthetic outcomes. In this retrospective study, unilateral periorbital cutaneous defects in 15 patients were repaired by the PEPSI technique. The ages of patients ranged from 3 to 46 years (average, 19 years). The outcome evaluations included scars (Vancouver Scar Scale and visual analog scale score), function and aesthetic appearance of eyelids, and patient satisfaction. The repair size was measured by the maximum advancement distance of skin flap during operation. All patients achieved an effective repair with a mean follow-up of 18.3 months. Except one with a small (approximately 0.3 cm) necrosis, all patients healed with no complication. The mean Vancouver Scar Scale and visual analog scale scores were 2.1 ± 1.7 and 8.5 ± 1.2, respectively. Ideal cosmetic and functional outcomes were achieved in 14 patients (93.3%). All patients achieved complete satisfaction except 1 patient with partial satisfaction. The mean maximum advancement distance of skin flap was 20.2 mm (range, 8-50 mm). This study demonstrated that the PEPSI technique is an effective method to repair large periorbital cutaneous defects with acceptable functional and aesthetic outcomes.

Hydrogel derived from porcine decellularized nerve tissue as a promising biomaterial for repairing peripheral nerve defects.

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Lin, Tao; Liu, Sheng; Chen, Shihao; Qiu, Shuai; Rao, Zilong; Liu, Jianghui; Zhu, Shuang; Yan, Liwei; Mao, Haiquan; Zhu, Qingtang; Quan, Daping; Liu, Xiaolin

2018-06-01

Decellularized matrix hydrogels derived from tissues or organs have been used for tissue repair due to their biocompatibility, tunability, and tissue-specific extracellular matrix (ECM) components. However, the preparation of decellularized peripheral nerve matrix hydrogels and their use to repair nerve defects have not been reported. Here, we developed a hydrogel from porcine decellularized nerve matrix (pDNM-G), which was confirmed to have minimal DNA content and retain collagen and glycosaminoglycans content, thereby allowing gelatinization. The pDNM-G exhibited a nanofibrous structure similar to that of natural ECM, and a ∼280-Pa storage modulus at 10 mg/mL similar to that of native neural tissues. Western blot and liquid chromatography tandem mass spectrometry analysis revealed that the pDNM-G consisted mostly of ECM proteins and contained primary ECM-related proteins, including fibronectin and collagen I and IV). In vitro experiments showed that pDNM-G supported Schwann cell proliferation and preserved cell morphology. Additionally, in a 15-mm rat sciatic nerve defect model, pDNM-G was combined with electrospun poly(lactic-acid)-co-poly(trimethylene-carbonate)conduits to bridge the defect, which did not elicit an adverse immune response and promoted the activation of M2 macrophages associated with a constructive remodeling response. Morphological analyses and electrophysiological and functional examinations revealed that the regenerative outcomes achieved by pDNM-G were superior to those by empty conduits and closed to those using rat decellularized nerve matrix allograft scaffolds. These findings indicated that pDNM-G, with its preserved ECM composition and nanofibrous structure, represents a promising biomaterial for peripheral nerve regeneration. Decellularized nerve allografts have been widely used to treat peripheral nerve injury. However, given their limited availability and lack of bioactive factors, efforts have been made to improve the efficacy

The Role of Resorbable Plate and Artificial Bone Substitute in Reconstruction of Large Orbital Floor Defect

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Ho Kwon

2016-01-01

Full Text Available It is essential to reduce and reconstruct bony defects adequately in large orbital floor fracture and defect. Among many reconstructive methods, alloplastic materials have attracted attention because of their safety and ease of use. We have used resorbable plates combined with artificial bone substitutes in large orbital floor defect reconstructions and have evaluated their long-term reliability compared with porous polyethylene plate. A total of 147 patients with traumatic orbital floor fracture were included in the study. Surgical results were evaluated by clinical evaluations, exophthalmometry, and computed tomography at least 12 months postoperatively. Both orbital floor height discrepancy and orbital volume change were calculated and compared with preoperative CT findings. The average volume discrepancy and vertical height discrepancies were not different between two groups. Also, exophthalmometric measurements were not significantly different between the two groups. No significant postoperative complication including permanent diplopia, proptosis, and enophthalmos was noted. Use of a resorbable plate with an artificial bone substitute to repair orbital floor defects larger than 2.5 cm2 in size yielded long-lasting, effective reconstruction without significant complications. We therefore propose our approach as an effective alternative method for large orbital floor reconstructions.

Successful three stage repair of a large congenital abdominal region defect

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Vaidehi Agrawal

2015-06-01

Full Text Available We present two infants born with large, right upper quadrant defects which cannot be categorized as either a gastroschisis or omphalocele. We successfully managed one infant with a three stage repair using polytetrafluoroethylene (PTFE patch, porcine urinary bladder matrix (UBM and delayed surgical closure. The second infant passed away due to parental consent care withdrawal.

Knee arthrodesis with lengthening: experience of using Ilizarov techniques to salvage large asymmetric defects following infected peri-articular fractures.

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Barwick, Thomas W; Montgomery, Richard J

2013-08-01

We present four patients with large bone defects due to infected internal fixation of knee condylar fractures. All were treated by debridement of bone and soft tissue and stabilisation with flap closure if required, followed by bone transport arthrodesis of the knee with simultaneous lengthening. Four patients (three male and one female), mean age 46.5 years (37-57 years), with posttraumatic osteomyelitis at the knee (three proximal tibia and one distal femur) were treated by debridement of infected tissue and removal of internal fixation. Substantial condylar bone defects resulted on the affected side of the knee joint (6-10 cm) with loss of the extensor mechanism in all tibial cases. Two patients required muscle flaps after debridement. All patients received intravenous antibiotics for at least 6 weeks. Bone transport with a circular frame was used to achieve an arthrodesis whilst simultaneously restoring a functional limb length. In three cases a 'peg in socket' docking technique was fashioned to assist stability and subsequent consolidation of the arthrodesis. Arthrodesis of the knee, free of recurrent infection, was successfully achieved in all cases. None has since required further surgery. Debridement to union took an average of 25 months (19-31 months). The median number of interventions undertaken was 9 (8-12). Two patients developed deep vein thrombosis (DVT), one complicated by PE, which delayed treatment. Two required surgical correction of pre-existent equinus contracture using frames. The median limb length discrepancy (LLD) at the end of treatment was 3 cm (3-4 cm). None has required subsequent amputation. Bone loss and infection both reduce the success rate of any arthrodesis. However, by optimising the host environment with eradication of infection by radical debridement, soft-tissue flaps when necessary and bone transport techniques to close the defect, one can achieve arthrodesis and salvage a useful limb. The residual LLD can result from not

Tendon tissue engineering and its role on healing of the experimentally induced large tendon defect model in rabbits: a comprehensive in vivo study.

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Meimandi-Parizi, Abdolhamid; Oryan, Ahmad; Moshiri, Ali

2013-01-01

Healing of large tendon defects is challenging. We studied the role of collagen implant with or without polydioxanone (PDS) sheath on the healing of a large Achilles tendon defect model, in rabbits. Sixty rabbits were divided into three groups. A 2 cm gap was created in the left Achilles tendon of all rabbits. In the control lesions, no implant was used. The other two groups were reconstructed by collagen and collagen-PDS implants respectively. The animals were clinically examined at weekly intervals and their lesions were observed by ultrasonography. Blood samples were obtained from the animals and were assessed for hematological analysis and determination of serum PDGF level, at 60 days post injury (DPI). The animals were then euthanized and their lesions were assessed for gross and histopathology, scanning electron microscopy, biomechanical testing, dry matter and hydroxyproline content. Another 65 pilot animals were also studied grossly and histopathologically to define the host implant interaction and graft incorporation at serial time points. The treated animals gained significantly better clinical scoring compared to the controls. Treatment with collagen and collagen-PDS implants significantly increased the biomechanical properties of the lesions compared to the control tendons at 60DPI (Ptendon. Implantation of the bioimplants had a significant role in initiating tendon healing and the implants were biocompatible, biodegradable and safe for application in tendon reconstructive surgery. The results of the present study may be valuable in clinical practice.

Repairing the Osteochondral Defect in Goat with the Tissue-Engineered Osteochondral Graft Preconstructed in a Double-Chamber Stirring Bioreactor

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Yang Pei

2014-01-01

Full Text Available To investigate the reparative efficacy of tissue-engineered osteochondral (TEO graft for repairing the osteochondral defect in goat, we designed a double-chamber stirring bioreactor to construct the bone and cartilage composites simultaneously in one β-TCP scaffold and observed the reparative effect in vivo. The osteochondral defects were created in goats and all the animals were divided into 3 groups randomly. In groups A, the defect was treated with the TEO which was cultured with mechanical stimulation of stir; in group B, the defect was treated with TEO which was cultured without mechanical stimulation of stir; in groups C, the defect was treated without TEO. At 12 weeks and 24 weeks after operation, the reparative effects in different groups were assessed and compared. The results indicated that the reparative effect of the TEO cultured in the bioreactor was better than the control group, and mechanical stimulation of stir could further improve the reparative effect. We provided a feasible and effective method to construct the TEO for treatment of osteochondral defect using autologous BMSCs and the double-chamber bioreactor.

Intermittent′ restrictive ventricular septal defect in Tetralogy of Fallot

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Sudhir S Shetkar

2015-01-01

Full Text Available Ventricular septal defect (VSD in Tetralogy of Fallot (TOF is usually large and non-restrictive with equalization of right and left ventricular pressures. Restrictive VSD in TOF is rare. We present an unusual case of TOF with restriction to VSD caused by accessory tricuspid valve tissue that varied with respiration.

Clinical observation on the reconstruction of large areas lower eyelid defect with Medpor spacer graft

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Hai-Yan Li

2014-08-01

Full Text Available AIM: To observe the effects of porous polyethylene(Medporas a spacer graft in the reconstruction of large areas eyelid defect after the operation of malignant tumors of lower eyelids.METHODS: Nineteen cases(19 eyesof malignant tumors of lower eyelid underwent the eyelid reconstruction were selected. Medpor lower eyelid inserts implantation were used to replace tarsal joint sliding conjunctival flap and pedicle flap, and repaired full-thickness lower eyelid defects then underwent eyelid reconstruction. RESULTS: Appearance of eyelids and functional improvements were satisfactory with no stimulation on the eyeball and no effect on the visual function. Implants is with no absorption, shift, exclusion or infection and no tumor recurrence in all cases during the follow up for 6-36mo.CONCLUSION: Medpor lower eyelid inserts implantation can instead tarsal plate for the reconstruction of medium to large areas lower eyelid defect, which is easy performing with rare complications. It is an ideal alternatives of tarsal plate.

[Feasibility of using connective tissue prosthesis for autoplastic repair of urinary bladder wall defects (an experimental study)].

Science.gov (United States)

Tyumentseva, N V; Yushkov, B G; Medvedeva, S Y; Kovalenko, R Y; Uzbekov, O K; Zhuravlev, V N

2016-12-01

Experiments on laboratory rats have shown the feasibility of autoplastic repair of urinary bladder wall defects using a connective-tissue capsule formed as the result of an inflammatory response to the presence of a foreign body. The formation of connective tissue prosthesis is characterized by developing fibrous connective tissue, ordering of collagen fibers, reducing the number of cells per unit area with a predominance of more mature cells - fibroblasts. With increasing time of observation, connective tissue prostheses were found to acquire a morphological structure similar to that of the urinary bladder wall. By month 12, the mucosa, the longitudinal and circular muscle layers were formed. The proposed method of partial autoplastic repair of urinary bladder wall is promising, has good long-term results, but requires further experimental studies.

Efficacy of novel synthetic bone substitutes in the reconstruction of large segmental bone defects in sheep tibiae

International Nuclear Information System (INIS)

Li, Jiao Jiao; Roohani-Esfahani, Seyed-Iman; Dunstan, Colin R; Quach, Terrence; Zreiqat, Hala; Steck, Roland; Saifzadeh, Siamak; Pivonka, Peter

2016-01-01

The treatment of large bone defects, particularly those with segmental bone loss, remains a significant clinical challenge as current approaches involving surgery or bone grafting often do not yield satisfactory long-term outcomes. This study reports the evaluation of novel ceramic scaffolds applied as bone graft substitutes in a clinically relevant in vivo model. Baghdadite scaffolds, unmodified or modified with a polycaprolactone coating containing bioactive glass nanoparticles, were implanted into critical-sized segmental bone defects in sheep tibiae for 26 weeks. Radiographic, biomechanical, μ-CT and histological analyses showed that both unmodified and modified baghdadite scaffolds were able to withstand physiological loads at the defect site, and induced substantial bone formation in the absence of supplementation with cells or growth factors. Notably, all samples showed significant bridging of the critical-sized defect (average 80%) with evidence of bone infiltration and remodelling within the scaffold implant. The unmodified and modified baghdadite scaffolds achieved similar outcomes of defect repair, although the latter may have an initial mechanical advantage due to the nanocomposite coating. The baghdadite scaffolds evaluated in this study hold potential for use as purely synthetic bone graft substitutes in the treatment of large bone defects while circumventing the drawbacks of autografts and allografts. (paper)

The influence of tethered epidermal growth factor on connective tissue progenitor colony formation

OpenAIRE

Marcantonio, Nicholas A.; Boehm, Cynthia A.; Rozic, Richard J.; Au, Ada; Wells, Alan; Muschler, George F.; Griffith, Linda G.

2009-01-01

Strategies to combine aspirated marrow cells with scaffolds to treat connective tissue defects are gaining increasing clinical attention and use. In situations such as large defects where initial survival and proliferation of transplanted connective tissue progenitors (CTPs) are limiting, therapeutic outcomes might be improved by using the scaffold to deliver growth factors that promote the early stages of cell function in the graft. Signaling by the epidermal growth factor receptor (EGFR) pl...

The healing of bony defects by cell-free collagen-based scaffolds compared to stem cell-seeded tissue engineered constructs.

LENUS (Irish Health Repository)

Lyons, Frank G

2010-12-01

One of the key challenges in tissue engineering is to understand the host response to scaffolds and engineered constructs. We present a study in which two collagen-based scaffolds developed for bone repair: a collagen-glycosaminoglycan (CG) and biomimetic collagen-calcium phosphate (CCP) scaffold, are evaluated in rat cranial defects, both cell-free and when cultured with MSCs prior to implantation. The results demonstrate that both cell-free scaffolds showed excellent healing relative to the empty defect controls and somewhat surprisingly, to the tissue engineered (MSC-seeded) constructs. Immunological analysis of the healing response showed higher M1 macrophage activity in the cell-seeded scaffolds. However, when the M2 macrophage response was analysed, both groups (MSC-seeded and non-seeded scaffolds) showed significant activity of these cells which are associated with an immunomodulatory and tissue remodelling response. Interestingly, the location of this response was confined to the construct periphery, where a capsule had formed, in the MSC-seeded groups as opposed to areas of new bone formation in the non-seeded groups. This suggests that matrix deposited by MSCs during in vitro culture may adversely affect healing by acting as a barrier to macrophage-led remodelling when implanted in vivo. This study thus improves our understanding of host response in bone tissue engineering.

The Use of Engineered Bilayered Skin (MyDermTM) in the Management of Massive Skin Defect in Grade III Gustilo-Anderson Open Fracture.

Science.gov (United States)

Mohamed Haflah, Nor Hazla; Ng, Min Hwei; Mohd Yunus, Mohd Heikal; Naicker, Amaramalar Selvee; Htwe, Ohnmar; Fahmi, Muhammad; Ishak, Mohamad Fikeri; Seet, Wan Tai; Khairoji, Khairul Anuar; Maarof, Manira; Chua, Kien Hui; Shamsuddin, Sharen Aini; Idrus, Ruszymah

2017-09-01

Open fracture Gustilo-Anderson grade IIIC is associated with higher risk of infection and problems with soft tissue coverage. Various methods have been used for soft tissue coverage in open fractures with large skin defect. We report a case of a patient who had grade IIIC open fracture of the tibia with posterior tibial artery injury. The patient underwent external fixation and reduction. Because of potential compartment syndrome after vascular repair, fasciotomy of the posterior compartment was performed. This wound, however, became infected and because of further debridement, gave rise to a large skin defect. A tissue engineered skin construct, MyDerm TM was employed to cover this large defect. Complete wound closure was achieved 35 days postimplantation. The patient then underwent plating of the tibia for nonunion with no adverse effect to the grafted site. The tibia eventually healed 5 months postplating, and the cosmetic appearance of the newly formed skin was satisfactory.

Soft tissue engineering with micronized-gingival connective tissues.

Science.gov (United States)

Noda, Sawako; Sumita, Yoshinori; Ohba, Seigo; Yamamoto, Hideyuki; Asahina, Izumi

2018-01-01

The free gingival graft (FGG) and connective tissue graft (CTG) are currently considered to be the gold standards for keratinized gingival tissue reconstruction and augmentation. However, these procedures have some disadvantages in harvesting large grafts, such as donor-site morbidity as well as insufficient gingival width and thickness at the recipient site post-treatment. To solve these problems, we focused on an alternative strategy using micronized tissue transplantation (micro-graft). In this study, we first investigated whether transplantation of micronized gingival connective tissues (MGCTs) promotes skin wound healing. MGCTs (≤100 µm) were obtained by mincing a small piece (8 mm 3 ) of porcine keratinized gingiva using the RIGENERA system. The MGCTs were then transplanted to a full skin defect (5 mm in diameter) on the dorsal surface of immunodeficient mice after seeding to an atelocollagen matrix. Transplantations of atelocollagen matrixes with and without micronized dermis were employed as experimental controls. The results indicated that MGCTs markedly promote the vascularization and epithelialization of the defect area 14 days after transplantation compared to the experimental controls. After 21 days, complete wound closure with low contraction was obtained only in the MGCT grafts. Tracking analysis of transplanted MGCTs revealed that some mesenchymal cells derived from MGCTs can survive during healing and may function to assist in wound healing. We propose here that micro-grafting with MGCTs represents an alternative strategy for keratinized tissue reconstruction that is characterized by low morbidity and ready availability. © 2017 Wiley Periodicals, Inc.

Usage of a rotational flap for coverage of a large central forehead defect

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El-Sabbagh, Ahmed Hassan

2017-02-01

Full Text Available Background: The forehead is a donor site for facial reconstruction but has no generous donor site for its coverage. All options of the reconstructive ladder can be used. A large rotation flap was used to reconstruct a big central forehead defect following failed previous repair in an elderly diabetic patient after a motor car accident. Case presentation: A 64-year-old diabetic man presented with an extensive central forehead defect after failed previous repair following a motor car accident. Coverage of the defect was performed using a flap based around the ear on one side in a rotation movement. An accepted functional and esthetic result was achieved after 3 months of Conclusion: A rotation flap based on arteries around the ear can be used for coverage of a difficult lesion in the central forehead. Level of evidence: Level V, therapeutic study

Guided tissue regeneration and platelet rich growth factor for the treatment of Grade II furcation defects: A randomized double-blinded clinical trial - A pilot study.

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Jenabian, Niloofar; Haghanifar, Sina; Ehsani, Hodis; Zahedi, Ehsan; Haghpanah, Masumeh

2017-01-01

The treatment of furcation area defects remained as a challenging issue in periodontal treatments. Regeneration treatment of furcation defects is the most discussed periodontal treatment. Although not completely hopeless in prognosis, the presence of the furcation involvement significantly increases the chance of tooth loss. The current research was conductedeto compare theeadditive effect of combined guided tissue regeneration (GTR) and platelet-rich growth factor (PRGF) on the treatment of furcation bony defects. A randomized, triple-blinded, split-mouth study was designed. It included patients with a moderate to severe chronic periodontitis with bilateral Grade II furcation involvement of first or second mandibular molars. Each side of mouth was randomly allocated for the treatment with either Bio-Gide American Society of Anesthesiologists GTR or a PRGF or PRGF by itself. Plaque index, gingival index, vertical clinical attachment level, vertical probing depth, recession depth (REC), horizontal probing depth, fornix to alveolar crest (FAC), fornix to base of defect (FBD), furcation vertical component and furcation horizontal component (FHC) were recorded. The current research was conducted to compare the additive effect of combined GTR and PRGF on treatment of furcation bony defects. Altman's nomogram, Kolmogorov-Smirnov test, Friedman test, general linear model, repeated measures, and paired t -test were used as statistical analysis in this research. P PRGF group ( P = 0.02). A significant improvement in the Grade II furcation defects treated with either GTR or PRGF/GTR was noticed. Further large-scale trials are needed to reveal differences of mentioned treatment in more details.

In vivo performance of combinations of autograft, demineralized bone matrix, and tricalcium phosphate in a rabbit femoral defect model

International Nuclear Information System (INIS)

Kim, Jinku; McBride, Sean; Hollinger, Jeffrey O; Dean, David D; Sylvia, Victor L; Doll, Bruce A

2014-01-01

Large bone defects may be treated with autologous or allogeneic bone preparations. Each treatment has advantages and disadvantages; therefore, a clinically viable option for treating large (e.g., gap) bone defects may be a combination of the two. In the present study, bone repair was determined with combinations of autografts, allografts, and synthetic bone grafts using an established rabbit femoral defect model. Bilateral unicortical femoral defects were surgically prepared and treated with combinatorial bone grafts according to one of seven treatment groups. Recipient sites were retrieved at six weeks. Cellular/tissue responses and new bone formation were assessed by histology and histomorphometry. Histological analysis images indicated neither evidence of inflammatory, immune responses, tissue necrosis, nor osteolysis. Data suggested co-integration of implanted agents with host and newly formed bone. Finally, the histomorphometric data suggested that the tricalcium phosphate-based synthetic bone graft substitute allowed new bone formation that was similar to the allograft (i.e., demineralized bone matrix, DBM). (paper)

Study on growth techniques and macro defects of large-size Nd:YAG laser crystal

Science.gov (United States)

Quan, Jiliang; Yang, Xin; Yang, Mingming; Ma, Decai; Huang, Jinqiang; Zhu, Yunzhong; Wang, Biao

2018-02-01

Large-size neodymium-doped yttrium aluminum garnet (Nd:YAG) single crystals were grown by the Czochralski method. The extinction ratio and wavefront distortion of the crystal were tested to determine the optical homogeneity. Moreover, under different growth conditions, the macro defects of inclusion, striations, and cracking in the as-grown Nd:YAG crystals were analyzed. Specifically, the inclusion defects were characterized using scanning electron microscopy and energy dispersive spectroscopy. The stresses of growth striations and cracking were studied via a parallel plane polariscope. These results demonstrate that improper growth parameters and temperature fields can enhance defects significantly. Thus, by adjusting the growth parameters and optimizing the thermal environment, high-optical-quality Nd:YAG crystals with a diameter of 80 mm and a total length of 400 mm have been obtained successfully.

A large-scale analysis of tissue-specific pathology and gene expression of human disease genes and complexes

DEFF Research Database (Denmark)

Hansen, Kasper Lage; Hansen, Niclas Tue; Karlberg, Erik, Olof, Linnart

2008-01-01

to be overexpressed in the normal tissues where defects cause pathology. In contrast, cancer genes and complexes were not overexpressed in the tissues from which the tumors emanate. We specifically identified a complex involved in XY sex reversal that is testis-specific and down-regulated in ovaries. We also......Heritable diseases are caused by germ-line mutations that, despite tissuewide presence, often lead to tissue-specific pathology. Here, we make a systematic analysis of the link between tissue-specific gene expression and pathological manifestations in many human diseases and cancers. Diseases were...

Gene expression in cardiac tissues from infants with idiopathic conotruncal defects

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Lofland Gary K

2011-01-01

Full Text Available Abstract Background Tetralogy of Fallot (TOF is the most commonly observed conotruncal congenital heart defect. Treatment of these patients has evolved dramatically in the last few decades, yet a genetic explanation is lacking for the failure of cardiac development for the majority of children with TOF. Our goal was to perform genome wide analyses and characterize expression patterns in cardiovascular tissue (right ventricle, pulmonary valve and pulmonary artery obtained at the time of reconstructive surgery from 19 children with tetralogy of Fallot. Methods We employed genome wide gene expression microarrays to characterize cardiovascular tissue (right ventricle, pulmonary valve and pulmonary artery obtained at the time of reconstructive surgery from 19 children with TOF (16 idiopathic and three with 22q11.2 deletions and compared gene expression patterns to normally developing subjects. Results We detected a signal from approximately 26,000 probes reflecting expression from about half of all genes, ranging from 35% to 49% of array probes in the three tissues. More than 1,000 genes had a 2-fold change in expression in the right ventricle (RV of children with TOF as compared to the RV from matched control infants. Most of these genes were involved in compensatory functions (e.g., hypertrophy, cardiac fibrosis and cardiac dilation. However, two canonical pathways involved in spatial and temporal cell differentiation (WNT, p = 0.017 and Notch, p = 0.003 appeared to be generally suppressed. Conclusions The suppression of developmental networks may represent a remnant of a broad malfunction of regulatory pathways leading to inaccurate boundary formation and improper structural development in the embryonic heart. We suggest that small tissue specific genomic and/or epigenetic fluctuations could be cumulative, leading to regulatory network disruption and failure of proper cardiac development.

In situ repair of bone and cartilage defects using 3D scanning and 3D printing

OpenAIRE

Li, Lan; Yu, Fei; Shi, Jianping; Shen, Sheng; Teng, Huajian; Yang, Jiquan; Wang, Xingsong; Jiang, Qing

2017-01-01

Three-dimensional (3D) printing is a rapidly emerging technology that promises to transform tissue engineering into a commercially successful biomedical industry. However, the use of robotic bioprinters alone is not sufficient for disease treatment. This study aimed to report the combined application of 3D scanning and 3D printing for treating bone and cartilage defects. Three different kinds of defect models were created to mimic three orthopedic diseases: large segmental defects of long bon...

Warning About the Use of Critical-Size Defects for the Translational Study of Bone Repair: Analysis of a Sheep Tibial Model.

Science.gov (United States)

Lammens, Johan; Maréchal, Marina; Geris, Lisbet; Van der Aa, Joshua; Van Hauwermeiren, Hadewych; Luyten, Frank P; Delport, Hendrik

2017-11-01

The repair of large long bone defects requires complex surgical procedures as the bone loss cannot simply be replaced by autologous grafts due to an insufficient bone stock of the human body. Tissue engineering strategies and the use of Advanced Therapy Medicinal Products (ATMPs) for these reconstructions remain a considerable challenge, in particular since robust outcomes in well-defined large animal models are lacking. To be suitable as a model for treatment of human sized bone defects, we developed a large animal model in both skeletally immature and mature sheep and made close observations on the spontaneous healing of defects. We warn for the spontaneous repair of large defects in immature animals, which can mask the (in)effectiveness of ATMP therapies, and propose the use of large 4.5 cm defects that are pretreated with a polymethylmethacrylate (PMMA) spacer in skeletally mature animals.

[The application of microvascular anastomotic coupler in vascular anastomosis of free tissue flap for reconstruction of defect after head and neck cancer resection].

Science.gov (United States)

Zhang, Y J; Wang, Z H; Li, C H; Chen, J

2017-09-07

Objective: To investigate the application and operation skills in vein anastomosis by microvascular anastomotic coupler (MAC) in reconstruction of defects after head and neck cancer resection. Methods: From August 2015 to July 2016, in Department of Head and Neck Surgery, Sichuan Cancer Hosipital, 17 cases underwent the reconstruction of defects after head and neck cancer resection with free tissue flaps, including forearm flaps in 11 casess, anterolateral flaps in 4 casess and fibula flaps in 2 casess. Totally 17 MAC were used, including 14 MAC for end-to-end anastomosis and 3 MAC for end-to-side anastomosis. SPSS 22.0 software was used to analyze the data. Results: Venous anastomoses in 17 free tissue flaps were successfully completed, with no anastomotic errhysis. All flaps survived well. The time required for vascular anastomoses with MAC varied 2-9 min, with average time of (4.2±2.3) min, which was significantly shorter than that with manually anastomosis (17.4 ± 2.7) min ( t =15.1, P anastomosis in free tissue flap for reconstruction of defect after head and neck cancer resection, which requires for less operation time and shows good results.

Direct transplantation of native pericytes from adipose tissue: A new perspective to stimulate healing in critical size bone defects.

Science.gov (United States)

König, Matthias A; Canepa, Daisy D; Cadosch, Dieter; Casanova, Elisa; Heinzelmann, Michael; Rittirsch, Daniel; Plecko, Michael; Hemmi, Sonja; Simmen, Hans-Peter; Cinelli, Paolo; Wanner, Guido A

2016-01-01

Fractures with a critical size bone defect (e.g., open fracture with segmental bone loss) are associated with high rates of delayed union and non-union. The prevention and treatment of these complications remain a serious issue in trauma and orthopaedic surgery. Autologous cancellous bone grafting is a well-established and widely used technique. However, it has drawbacks related to availability, increased morbidity and insufficient efficacy. Mesenchymal stromal cells can potentially be used to improve fracture healing. In particular, human fat tissue has been identified as a good source of multilineage adipose-derived stem cells, which can be differentiated into osteoblasts. The main issue is that mesenchymal stromal cells are a heterogeneous population of progenitors and lineage-committed cells harboring a broad range of regenerative properties. This heterogeneity is also mirrored in the differentiation potential of these cells. In the present study, we sought to test the possibility to enrich defined subpopulations of stem/progenitor cells for direct therapeutic application without requiring an in vitro expansion. We enriched a CD146+NG2+CD45- population of pericytes from freshly isolated stromal vascular fraction from mouse fat tissue and tested their osteogenic differentiation capacity in vitro and in vivo in a mouse model for critical size bone injury. Our results confirm the ability of enriched CD146+NG2+CD45- cells to efficiently generate osteoblasts in vitro, to colonize cancellous bone scaffolds and to successfully contribute to regeneration of large bone defects in vivo. This study represents proof of principle for the direct use of enriched populations of cells with stem/progenitor identity for therapeutic applications. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Dual Delivery of BMP-2 and bFGF from a New Nano-Composite Scaffold, Loaded with Vascular Stents for Large-Size Mandibular Defect Regeneration

Directory of Open Access Journals (Sweden)

Hang Zhao

2013-06-01

Full Text Available The aim of this study was to investigate the feasibility and advantages of the dual delivery of bone morphogenetic protein-2 (BMP-2 and basic fibroblast growth factor (bFGF from nano-composite scaffolds (PLGA/PCL/nHA loaded with vascular stents (PLCL/Col/nHA for large bone defect regeneration in rabbit mandibles. Thirty-six large bone defects were repaired in rabbits using engineering bone composed of allogeneic bone marrow mesenchymal stem cells (BMSCs, bFGF, BMP-2 and scaffolds composed of PLGA/PCL/nHA loaded with PLCL/Col/nHA. The experiments were divided into six groups: BMSCs/bFGF/BMP-2/scaffold, BMSCs/BMP-2/scaffold, BMSCs/bFGF/scaffold, BMSCs/scaffold, scaffold alone and no treatment. Sodium alginate hydrogel was used as the carrier for BMP-2 and bFGF and its features, including gelling, degradation and controlled release properties, was detected by the determination of gelation and degradation time coupled with a controlled release study of bovine serum albumin (BSA. AlamarBlue assay and alkaline phosphatase (ALP activity were used to evaluate the proliferation and osteogenic differentiation of BMSCs in different groups. X-ray and histological examinations of the samples were performed after 4 and 12 weeks post-implantation to clarify new bone formation in the mandible defects. The results verified that the use of sodium alginate hydrogel as a controlled release carrier has good sustained release ability, and the combined application of bFGF and BMP-2 could significantly promote the proliferation and osteogenic differentiation of BMSCs (p < 0.05 or p < 0.01. In addition, X-ray and histological examinations of the samples exhibited that the dual release group had significantly higher bone formation than the other groups. The above results indicate that the delivery of both growth factors could enhance new bone formation and vascularization compared with delivery of BMP-2 or bFGF alone, and may supply a promising way of repairing large

The Use of Tensor Fascia Lata Pedicled Flap in Reconstructing Full Thickness Abdominal Wall Defects and Groin Defects Following Tumor Ablation

International Nuclear Information System (INIS)

Rifaat, M.A.; Abdel Gawad, W.S.

2005-01-01

The tensor fascia lata is a versatile flap with many uses in reconstructive plastic surgery. As a pedicled flap its reach to the lower abdomen and groin made it an attractive option for reconstructing soft tissue defects after tumor ablation. However, debate exists on the safe dimension of the flap, as distal tip necrosis is common. Also, the adequacy of the fascia lata as a sole substitute for abdominal wall muscles has been disputable. The aim of the current study is to report our experience and clinical observations with this flap in reconstructing those challenging defects and to discuss the possible options to minimize the latter disputable issues. Patients and Methods: From April 2001 to April 2004, 12 pedicled TFL flaps were used to reconstruct 5 central abdominal wall full thickness defects and 6 groin soft tissue defects following tumor resection. ]n one case, bilateral flaps were used to reconstruct a large central abdominal wall defect. There were 4 males and 7 females. Their age ranged from 19 to 60. From the abdominal wall defects group, all repairs were enforced primarily with a prolene mesh except for one patient who was the first in this study. Patients presenting with groin defects required coverage of exposed vessels following tumor resection. All patients in the current study underwent immediate reconstruction. The resulting soft tissue defects in this study were due to resection of 4 abdominal wall desmoid tumors, a colonic carcinoma infiltrating the abdominal wall, 4 primary groin soft developed in a flap used to cover a groin defect. In the former 3 cases, The flap was simply transposed without complete islanding of the flap. In the latter case, a very large flap was harvested beyond the safe limits with its distal edge just above the knee. In addition, wound dehiscence of the flap occurred in 2 other cases from the groin group. Nevertheless, all the wounds healed spontaneously with repeated dressings. Out of the 5 cases that underwent

Concentrations of cadmium and selected essential elements in malignant large intestine tissue

Science.gov (United States)

Dziki, Adam; Kilanowicz, Anna; Sapota, Andrzej; Duda-Szymańska, Joanna; Daragó, Adam

2015-01-01

Introduction Colorectal cancer is one of the most common cancers worldwide. Incidence rates of large intestine cancer indicate a role of environmental and occupational factors. The role of essential elements and their interaction with toxic metals can contribute to the explanation of a complex mechanism by which large intestine cancer develops. Bearing this in mind, determining the levels of essential and toxic elements in tissues (organs), as well as in body fluids, seems to shed light on their role in the mode of action in malignant disease. Aim Determination of the levels of cadmium, zinc, copper, selenium, calcium, magnesium, and iron in large intestine malignant tissue. Material and methods Two intraoperative intestine sections were investigated: one from the malignant tissue and the other one from the normal tissue, collected from each person with diagnosed large intestine cancer. Cadmium, zinc, copper, calcium, magnesium, and iron levels were determined with atomic absorption spectrometry, and selenium levels by spectrofluorimetric method. Results The levels of copper, selenium, and magnesium were higher in the malignant than in normal tissues. In addition, the zinc/copper and calcium/magnesium relationship was altered in malignant tissue, where correlations were lower compared to non-malignant tissue. Conclusions The results seems to demonstrate disturbed homeostasis of some essential elements. However, it is hard to confirm their involvement in the aetiology of colorectal cancer. PMID:27110307

Simultaneous large band gaps and localization of electromagnetic and elastic waves in defect-free quasicrystals.

Science.gov (United States)

Yu, Tianbao; Wang, Zhong; Liu, Wenxing; Wang, Tongbiao; Liu, Nianhua; Liao, Qinghua

2016-04-18

We report numerically large and complete photonic and phononic band gaps that simultaneously exist in eight-fold phoxonic quasicrystals (PhXQCs). PhXQCs can possess simultaneous photonic and phononic band gaps over a wide range of geometric parameters. Abundant localized modes can be achieved in defect-free PhXQCs for all photonic and phononic polarizations. These defect-free localized modes exhibit multiform spatial distributions and can confine simultaneously electromagnetic and elastic waves in a large area, thereby providing rich selectivity and enlarging the interaction space of optical and elastic waves. The simulated results based on finite element method show that quasiperiodic structures formed of both solid rods in air and holes in solid materials can simultaneously confine and tailor electromagnetic and elastic waves; these structures showed advantages over the periodic counterparts.

Decellularized Tissue and Cell-Derived Extracellular Matrices as Scaffolds for Orthopaedic Tissue Engineering

Science.gov (United States)

Cheng, Christina W.; Solorio, Loran D.; Alsberg, Eben

2014-01-01

The reconstruction of musculoskeletal defects is a constant challenge for orthopaedic surgeons. Musculoskeletal injuries such as fractures, chondral lesions, infections and tumor debulking can often lead to large tissue voids requiring reconstruction with tissue grafts. Autografts are currently the gold standard in orthopaedic tissue reconstruction; however, there is a limit to the amount of tissue that can be harvested before compromising the donor site. Tissue engineering strategies using allogeneic or xenogeneic decellularized bone, cartilage, skeletal muscle, tendon and ligament have emerged as promising potential alternative treatment. The extracellular matrix provides a natural scaffold for cell attachment, proliferation and differentiation. Decellularization of in vitro cell-derived matrices can also enable the generation of autologous constructs from tissue specific cells or progenitor cells. Although decellularized bone tissue is widely used clinically in orthopaedic applications, the exciting potential of decellularized cartilage, skeletal muscle, tendon and ligament cell-derived matrices has only recently begun to be explored for ultimate translation to the orthopaedic clinic. PMID:24417915

Antibody-Mediated Osseous Regeneration for Bone Tissue Engineering in Canine Segmental Defects

Directory of Open Access Journals (Sweden)

A. Khojasteh

2018-01-01

Full Text Available Among many applications of therapeutic monoclonal antibodies (mAbs, a unique approach for regenerative medicine has entailed antibody-mediated osseous regeneration (AMOR. In an effort to identify a clinically relevant model of craniofacial defect, the present study investigated the efficacy of mAb specific for bone morphogenetic protein- (BMP- 2 to repair canine segmental mandibular continuity defect model. Accordingly, a 15 mm unilateral segmental defect was created in mandible and fixated with a titanium plate. Anorganic bovine bone mineral with 10% collagen (ABBM-C was functionalized with 25 μg/mL of either chimeric anti-BMP-2 mAb or isotype-matched mAb (negative control. Recombinant human (rh BMP-2 served as positive control. Morphometric analyses were performed on computed tomography (CT and histologic images. Bone densities within healed defect sites at 12 weeks after surgery were 1360.81 ± 10.52 Hounsfield Unit (HU, 1044.27 ± 141.16 HU, and 839.45 ± 179.41 HU, in sites with implanted anti-BMP-2 mAb, rhBMP-2, and isotype mAb groups, respectively. Osteoid bone formation in anti-BMP-2 mAb (42.99% ± 8.67 and rhBMP-2 (48.97% ± 2.96 groups was not significantly different but was higher (p<0.05 than in sites with isotype control mAb (26.8% ± 5.35. In view of the long-term objective of translational application of AMOR in humans, the results of the present study demonstrated the feasibility of AMOR in a large clinically relevant animal model.

Improvement in the repair of defects in maxillofacial soft tissue in irradiated minipigs by a mixture of adipose-derived stem cells and platelet-rich fibrin.

Science.gov (United States)

Chen, Yuanzheng; Niu, Zhanguo; Xue, Yan; Yuan, Fukang; Fu, Yanjie; Bai, Nan

2014-10-01

To find out if adipose-derived stem cells (ASC) and platelet-rich fibrin (PRF), alone or combined, had any effect on the repair of maxillofacial soft tissue defects in irradiated minipigs, ASC were isolated, characterised, and expanded. Twenty female minipigs, the right parotid glands of which had been irradiated, were randomly divided into 4 groups of 5 each: those in the first group were injected with both ASC and PRF (combined group), the second group was injected with ASC alone (ASC group), the third group with PRF alone (PRF group), and the fourth group with phosphate buffer saline (PBS) (control group). Six months after the last injection, the size and depth of each defect were assessed, and subcutaneous tissues were harvested, stained with haematoxylin and eosin, and examined immunohistologically and for apoptosis. Expanded cells were successfully isolated and identified. Six months after injection the defects in the 3 treated groups were significantly smaller (p<0.001) and shallower (p<0.001) than those in the control group. Those in the combined group were the smallest and shallowest. Haematoxylin and eosin showed that the 3 treated groups contained more subcutaneous adipose tissue than the control group, and also had significantly greater vascular density (p<0.001) and fewer apoptotic cells (p<0.001). Both ASC and PRF facilitate the repair of defects in maxillofacial soft tissue in irradiated minipigs, and their combined use is more effective than their use as single agents. Copyright © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Emergency repair of upper extremity large soft tissue and vascular injuries with flow-through anterolateral thigh free flaps.

Science.gov (United States)

Zhan, Yi; Fu, Guo; Zhou, Xiang; He, Bo; Yan, Li-Wei; Zhu, Qing-Tang; Gu, Li-Qiang; Liu, Xiao-Lin; Qi, Jian

2017-12-01

Complex extremity trauma commonly involves both soft tissue and vascular injuries. Traditional two-stage surgical repair may delay rehabilitation and functional recovery, as well as increase the risk of infections. We report a single-stage reconstructive surgical method that repairs soft tissue defects and vascular injuries with flow-through free flaps to improve functional outcomes. Between March 2010 and December 2016 in our hospital, 5 patients with severe upper extremity trauma received single-stage reconstructive surgery, in which a flow-through anterolateral thigh free flap was applied to repair soft tissue defects and vascular injuries simultaneously. Cases of injured artery were reconstructed with the distal trunk of the descending branch of the lateral circumflex femoral artery. A segment of adjacent vein was used if there was a second artery injury. Patients were followed to evaluate their functional recoveries, and received computed tomography angiography examinations to assess peripheral circulation. Two patients had post-operative thumb necrosis; one required amputation, and the other was healed after debridement and abdominal pedicle flap repair. The other 3 patients had no major complications (infection, necrosis) to the recipient or donor sites after surgery. All the patients had achieved satisfactory functional recovery by the end of the follow-up period. Computed tomography angiography showed adequate circulation in the peripheral vessels. The success of these cases shows that one-step reconstructive surgery with flow-through anterolateral thigh free flaps can be a safe and effective treatment option for patients with complex upper extremity trauma with soft tissue defects and vascular injuries. Copyright © 2017. Published by Elsevier Ltd.

Segmentation, surface rendering, and surface simplification of 3-D skull images for the repair of a large skull defect

Science.gov (United States)

Wan, Weibing; Shi, Pengfei; Li, Shuguang

2009-10-01

Given the potential demonstrated by research into bone-tissue engineering, the use of medical image data for the rapid prototyping (RP) of scaffolds is a subject worthy of research. Computer-aided design and manufacture and medical imaging have created new possibilities for RP. Accurate and efficient design and fabrication of anatomic models is critical to these applications. We explore the application of RP computational methods to the repair of a pediatric skull defect. The focus of this study is the segmentation of the defect region seen in computerized tomography (CT) slice images of this patient's skull and the three-dimensional (3-D) surface rendering of the patient's CT-scan data. We see if our segmentation and surface rendering software can improve the generation of an implant model to fill a skull defect.

Can Bone Tissue Engineering Contribute to Therapy Concepts after Resection of Musculoskeletal Sarcoma?

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Boris Michael Holzapfel

2013-01-01

Full Text Available Resection of musculoskeletal sarcoma can result in large bone defects where regeneration is needed in a quantity far beyond the normal potential of self-healing. In many cases, these defects exhibit a limited intrinsic regenerative potential due to an adjuvant therapeutic regimen, seroma, or infection. Therefore, reconstruction of these defects is still one of the most demanding procedures in orthopaedic surgery. The constraints of common treatment strategies have triggered a need for new therapeutic concepts to design and engineer unparalleled structural and functioning bone grafts. To satisfy the need for long-term repair and good clinical outcome, a paradigm shift is needed from methods to replace tissues with inert medical devices to more biological approaches that focus on the repair and reconstruction of tissue structure and function. It is within this context that the field of bone tissue engineering can offer solutions to be implemented into surgical therapy concepts after resection of bone and soft tissue sarcoma. In this paper we will discuss the implementation of tissue engineering concepts into the clinical field of orthopaedic oncology.

In situ repair of bone and cartilage defects using 3D scanning and 3D printing.

Science.gov (United States)

Li, Lan; Yu, Fei; Shi, Jianping; Shen, Sheng; Teng, Huajian; Yang, Jiquan; Wang, Xingsong; Jiang, Qing

2017-08-25

Three-dimensional (3D) printing is a rapidly emerging technology that promises to transform tissue engineering into a commercially successful biomedical industry. However, the use of robotic bioprinters alone is not sufficient for disease treatment. This study aimed to report the combined application of 3D scanning and 3D printing for treating bone and cartilage defects. Three different kinds of defect models were created to mimic three orthopedic diseases: large segmental defects of long bones, free-form fracture of femoral condyle, and International Cartilage Repair Society grade IV chondral lesion. Feasibility of in situ 3D bioprinting for these diseases was explored. The 3D digital models of samples with defects and corresponding healthy parts were obtained using high-resolution 3D scanning. The Boolean operation was used to achieve the shape of the defects, and then the target geometries were imported in a 3D bioprinter. Two kinds of photopolymerized hydrogels were synthesized as bioinks. Finally, the defects of bone and cartilage were restored perfectly in situ using 3D bioprinting. The results of this study suggested that 3D scanning and 3D bioprinting could provide another strategy for tissue engineering and regenerative medicine.

Plant photonics: application of optical coherence tomography to monitor defects and rots in onion

International Nuclear Information System (INIS)

Meglinski, I V; Terry, L A; Buranachai, C

2010-01-01

The incidence of physiological and/or pathological defects in many fresh produce types is still unacceptably high and accounts for a large proportion of waste. With increasing interest in food security their remains strong demand in developing reliable and cost effective technologies for non-destructive screening of internal defects and rots, these being deemed unacceptable by consumers. It is well recognized that the internal defects and structure of turbid scattering media can be effectively visualized by using optical coherence tomography (OCT). In the present study, the high spatial resolution and advantages of OCT have been demonstrated for imaging the skins and outer laminae (concentric tissue layers) of intact whole onion bulbs with a view to non-invasively visualizing potential incidence/severity of internal defects

Plant photonics: application of optical coherence tomography to monitor defects and rots in onion

Science.gov (United States)

Meglinski, I. V.; Buranachai, C.; Terry, L. A.

2010-04-01

The incidence of physiological and/or pathological defects in many fresh produce types is still unacceptably high and accounts for a large proportion of waste. With increasing interest in food security their remains strong demand in developing reliable and cost effective technologies for non-destructive screening of internal defects and rots, these being deemed unacceptable by consumers. It is well recognized that the internal defects and structure of turbid scattering media can be effectively visualized by using optical coherence tomography (OCT). In the present study, the high spatial resolution and advantages of OCT have been demonstrated for imaging the skins and outer laminae (concentric tissue layers) of intact whole onion bulbs with a view to non-invasively visualizing potential incidence/severity of internal defects.

Determination of bone and tissue concentrations of teicoplanin mixed with hydroxyapatite cement to repair cortical defects.

Science.gov (United States)

Eggenreich, K; Zeipper, U; Schwendenwein, E; Hadju, S; Kaltenecker, G; Laslo, I; Lang, S; Roschger, P; Vecsei, V; Wintersteiger, R

2002-01-01

A highly specific and sensitive isocratic reversed-phase high performance liquid chromatography (HPLC) method for the determination of the major component of teicoplanin in tissue is reported. Comparing fluorescamine and o-phthalaldehyde (OPA) as derivatizing agents, the derivative formed with the latter exhibits superior fluorescence intensity allowing detection of femtomole quantities. Pretreatment for tissue samples is by solid-phase extraction which uses Bakerbond PolarP C(18) cartridges and gives effective clean up from endogenous by-products. Linearity was given from 0.6 to 100 ng per injection. The coefficient of variation did not exceed 5.8% for both interday and intraday assays. It was found that when bone defects are repaired with a hydroxyapatite-teicoplanin mixture, the antibiotic does not degrade, even when it is in the cement for several months. The stability of teicoplanin in bone cement was determined fluorodensitometrically.

Evaluation of Osteoconductive and Osteogenic Potential of a Dentin-Based Bone Substitute Using a Calvarial Defect Model

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Ibrahim Hussain

2012-01-01

Full Text Available The aim of this study was to assess the osteoconductive and osteogenic properties of processed bovine dentin using a robust rabbit calvarial defect model. In total, 16 New Zealand White rabbits were operated to create three circular defects in the calvaria. One defect was left unfilled, one filled with collected autogenous bone, and the third defect was filled with the dentin-based bone substitute. Following surgery and after a healing period of either 1 or 6 weeks, a CT scan was obtained. Following sacrificing, the tissues were processed for histological examination. The CT data showed the density in the area grafted with the dentin-based material was higher than the surrounding bone and the areas grafted with autologous bone after 1 week and 6 weeks of healing. The area left unfilled remained an empty defect after 1 week and 6 weeks. Histological examination of the defects filled with the dentin product after 6 weeks showed soft tissue encapsulation around the dentin particles. It can be concluded that the rabbit calvarial model used in this study is a robust model for the assessment of bone materials. Bovine dentin is a biostable material; however, it may not be suitable for repairing large 4-wall defects.

MRI of fibrous cortical defect and non-ossifying fibroma

Energy Technology Data Exchange (ETDEWEB)

Mishima, Yoshiko; Aoki, Takatoshi; Watanabe, Hideyuki; Nakata, Hajime; Hashimoto, Hiroshi; Nakamura, Toshitaka [Univ. of Occupational and Environmental Health, Kitakyushu, Fukuoka (Japan). School of Medicine

1999-02-01

Fibrous cortical defect and non-ossifying fibroma are the benign fibrous lesions of bone commonly involving children. Their diagnosis is usually done with radiography, and MR examinations are rarely performed. We evaluated MRI findings of 11 lesions in 10 cases of fibrous cortical defect and non-ossifying fibroma. Signal intensity of the lesions was varied and large lesions (2 cm<) tended to show heterogeneous signal intensity on both T1-weighted and T2-weighted images corresponding to a mixture of components including fibrous tissue, hemosiderin and foam cells. MRI helps to delineate the extent of the involved bone and to assess the various histological components of the lesions. However, their diagnosis is basically made on the radiographic findings and the role of MRI is limited. (author)

Usefulness of pulse-wave doppler tissue sampling and dobutamine stress echocardiography for identification of false positive inferior wall defects in SPECT

International Nuclear Information System (INIS)

Altinmakas, S.; Dagdeviren, B.; Turkmen, M.; Gursurer, M.; Say, B.; Tezel, T.; Ersek, B.

2000-01-01

False positive inferior wall perfusion defects restrict the accuracy of SPECT in diagnosis of coronary artery disease (CAD). Pulse-Wave Tissue Doppler (PWTD) has been recently proposed to assess regional wall motion velocities. The objectives of this study were to evaluate the presence of CAD by using PWTD during dobutamine stress echocardiography (DSE) in patients with an inferior perfusion defect detected by SPECT and compare PWTD parameters of normal cases with patients who had inferior perfusion defect and CAD. Sixty-five patients (mean age 58±8 years, 30 men) with a normal LV systolic function at rest according to echocardiographic evaluation with an inferior ischemia determined by SPECT and a control group (CG) of 34 normal cases (mean age 56±7 years, 16 men) were included in this study. All patients underwent a standard DSE (up to 40 μg/kg/min with additional atropine during sub-maximum heart rate responses). Pulse-wave Doppler tissue sampling of inferior wall was performed in the apical 2-chamber view at rest and stress. The coronary angiography was performed within 24 hours. The results were evaluated for the prediction of significant right coronary artery (RCA) and/or left circumflex coronary artery (CX) with narrowing (≥50% diameter stenosis, assessed by quantitative coronary angiography). It was observed that the peak stress mean E/A ratio was lower in patients with CAD when compared to patients without CAD (0.78±0.2 versus 1.29±0.11 p<0.0001). Also the peak stress E/A ratio of normal cases was significantly higher than patients who had CAD (1.19±0.3 versus 0.78±0.2 p<0.0001). When the cut off point for the E/A ratio was determined as 1, the sensitivity and specificity of dobutamine stress PWTD E/A were 89% and 86%, respectively. The peak stress E/A ratio was higher than 1 in all patients with a false positive perfusion defect. Systolic S velocity increase during DSE was significantly lower in patients with CAD (54%±17 versus 99%±24 p=0

Hyaluronic acid hydrogels with IKVAV peptides for tissue repair and axonal regeneration in an injured rat brain

International Nuclear Information System (INIS)

Wei, Y T; Tian, W M; Yu, X; Cui, F Z; Hou, S P; Xu, Q Y; Lee, In-Seop

2007-01-01

A biocompatible hydrogel of hyaluronic acid with the neurite-promoting peptide sequence of IKVAV was synthesized. The characterization of the hydrogel shows an open porous structure and a large surface area available for cell interaction. Its ability to promote tissue repair and axonal regeneration in the lesioned rat cerebrum is also evaluated. After implantation, the polymer hydrogel repaired the tissue defect and formed a permissive interface with the host tissue. Axonal growth occurred within the microstructure of the network. Within 6 weeks the polymer implant was invaded by host-derived tissue, glial cells, blood vessels and axons. Such a hydrogel matrix showed the properties of neuron conduction. It has the potential to repair tissue defects in the central nervous system by promoting the formation of a tissue matrix and axonal growth by replacing the lost tissue

Iatrogenic Urethral Defect Repairment: A Case Report

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Ulas Fidan

2013-10-01

Full Text Available    Iatrogenic urethral defect is a complication that occurs after vaginal surgical procedures. Many surgical methods according to place of defect are described in case of injury of urethra. In this article, we reported the repairment of distal urethral defect with the help of greft taken from labia minor. This defect is made by the excision of the granulation tissue that occurred after chronic paraurethral  gland infection.

Root cementum modulates periodontal regeneration in Class III furcation defects treated by the guided tissue regeneration technique: a histometric study in dogs.

Science.gov (United States)

Gonçalves, Patricia F; Gurgel, Bruno C V; Pimentel, Suzana P; Sallum, Enilson A; Sallum, Antonio W; Casati, Márcio Z; Nociti, Francisco H

2006-06-01

Because the possibility of root cementum preservation as an alternative approach for the treatment of periodontal disease has been demonstrated, this study aimed to histometrically evaluate the effect of root cementum on periodontal regeneration. Bilateral Class III furcation defects were created in dogs, and each dog was randomly assigned to receive one of the following treatments: control (group A): scaling and root planing with the removal of root cementum; or test (group B): removal of soft microbial deposits by polishing the root surface with rubber cups and polishing paste, aiming at maximum cementum preservation. Guided tissue regeneration (GTR) was applied to both groups. Four months after treatment, a superior length of new cementum (3.59 +/- 1.67 mm versus 6.20 +/- 2.26 mm; P = 0.008) and new bone (1.86 +/- 1.76 mm versus 4.62 +/- 3.01 mm; P = 0.002) and less soft tissue along the root surface (2.77 +/- 0.79 mm versus 1.10 +/- 1.48 mm; P = 0.020) was observed for group B. Additionally, group B presented a larger area of new bone (P = 0.004) and a smaller area of soft tissue (P = 0.008). Within the limits of this study, root cementum may modulate the healing pattern obtained by guided tissue regeneration in Class III furcation defects.

The distally-based island ulnar artery perforator flap for wrist defects

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Karki Durga

2007-01-01

Full Text Available Background: Reconstruction of soft tissue defects around the wrist with exposed tendons, joints, nerves and bone represents a challenge to plastic surgeons, and such defects necessitate flap coverage to preserve hand functions and to protect its vital structures. We evaluated the use of a distally-based island ulnar artery perforator flap in patients with volar soft tissue defects around the wrist. Materials and Methods: Between June 2004 and June 2006, seven patients of soft tissue defects on the volar aspect of the wrist underwent distally-based island ulnar artery perforator flap. Out of seven patients, five were male and two patients were female. This flap was used in the reconstruction of the post road traffic accident defects in four patients and post electric burn defects in three patients. Flap was raised on one or two perforators and was rotated to 180°. Results: All flaps survived completely. Donor sites were closed primarily without donor site morbidity. Conclusion: The distally-based island Ulnar artery perforator flap is convenient, reliable, easy to manage and is a single-stage technique for reconstructing soft tissue defects of the volar aspect of the wrist. Early use of this flap allows preservation of vital structures, decreases morbidity and allows for early rehabilitation.

Unicortical critical size defect of rabbit tibia is larger than 8 mm

DEFF Research Database (Denmark)

Aaboe, M; Pinholt, E M; Hjørting-Hansen, E

1994-01-01

The critical-size defect is important as an experimental model to test bone repair materials. Guided tissue regeneration is an established method for tissue regeneration within periodontal surgery. Bony defects covered by a membrane are allowed to be filled by bony tissue. Healing of 8-mm...

Micrometer scale guidance of mesenchymal stem cells to form structurally oriented large-scale tissue engineered cartilage.

Science.gov (United States)

Chou, Chih-Ling; Rivera, Alexander L; Williams, Valencia; Welter, Jean F; Mansour, Joseph M; Drazba, Judith A; Sakai, Takao; Baskaran, Harihara

2017-09-15

roll-up method, we have developed large scale MSC based tissue-engineered cartilage that shows microscale structural organization and enhanced compressive properties compared to current tissue engineered constructs. Tissue engineered cartilage constructs made with human mesenchymal stem cells (hMSCs), scaffolds and bioactive factors are a promising solution to treat cartilage defects. A major disadvantage of these constructs is their inferior mechanical properties compared to the native tissue, which is likely due to the lack of structural organization of the extracellular matrix of the engineered constructs. In this study, we developed three-dimensional (3-D) cartilage constructs from rectangular scaffold sheets containing hMSCs in micro-guidance channels and characterized their mechanical properties and metabolic requirements. The work led to a novel roll-up method to embed 2-D microscale structures in 3-D constructs. Further, micro-guidance channels incorporated within the 3-D cartilage constructs led to the production of aligned cell-produced matrix and enhanced mechanical function. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Use of autologous platelet - Rich plasma in the treatment of intrabony defects

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Sharath K Shetty

2009-01-01

Treatment of intrabony defects by autologous PRP gel alone caused significant soft tissue clinical improvement as well as hard tissue defect fill as evidenced by SSD view in spiral computed tomography.

Immobile defects in ferroelastic walls: Wall nucleation at defect sites

Science.gov (United States)

He, X.; Salje, E. K. H.; Ding, X.; Sun, J.

2018-02-01

Randomly distributed, static defects are enriched in ferroelastic domain walls. The relative concentration of defects in walls, Nd, follows a power law distribution as a function of the total defect concentration C: N d ˜ C α with α = 0.4 . The enrichment Nd/C ranges from ˜50 times when C = 10 ppm to ˜3 times when C = 1000 ppm. The resulting enrichment is due to nucleation at defect sites as observed in large scale MD simulations. The dynamics of domain nucleation and switching is dependent on the defect concentration. Their energy distribution follows the power law with exponents during yield between ɛ ˜ 1.82 and 2.0 when the defect concentration increases. The power law exponent is ɛ ≈ 2.7 in the plastic regime, independent of the defect concentration.

Effects of in-cascade defect clustering on near-term defect evolution

Energy Technology Data Exchange (ETDEWEB)

Heinisch, H.L. [Pacific Northwest National Lab., Richland, WA (United States)

1997-08-01

The effects of in-cascade defect clustering on the nature of the subsequent defect population are being studied using stochastic annealing simulations applied to cascades generated in molecular dynamics (MD) simulations. The results of the simulations illustrates the strong influence of the defect configuration existing in the primary damage state on subsequent defect evolution. The large differences in mobility and stability of vacancy and interstitial defects and the rapid one-dimensional diffusion of small, glissile interstitial loops produced directly in cascades have been shown to be significant factors affecting the evolution of the defect distribution. In recent work, the effects of initial cluster sizes appear to be extremely important.

Effects of large pressure amplitude low frequency noise in the parotid gland perivasculo-ductal connective tissue.

Science.gov (United States)

Oliveira, Pedro; Brito, José; Mendes, João; da Fonseca, Jorge; Águas, Artur; Martins dos Santos, José

2013-01-01

In tissues and organs exposed to large pressure amplitude low frequency noise fibrosis occurs in the absence of inflammatory signs, which is thought to be a protective response. In the parotid gland the perivasculo-ductal connective tissue surrounds arteries, veins and the ductal tree. Perivasculo-ductal connective tissue is believed to function as a mechanical stabilizer of the glandular tissue. In order to quantify the proliferation of perivasculo-ductal connective tissue in large pressure amplitude low frequency noise-exposed rats we used sixty Wistar rats which were equally divided into 6 groups. One group kept in silence, and the remaining five exposed to continuous large pressure amplitude low frequency noise: g1-168h (1 week); g2-504h (3 weeks); g3-840h (5 weeks); g4-1512h (9 weeks); and g5-2184h (13 weeks). After exposure, parotid glands were removed and the perivasculo-ductal connective tissue area was measured in all groups. We applied ANOVA statistical analysis, using SPSS 13.0. The global trend is an increase in the average perivasculo-ductal connective tissue areas, that develops linearly and significantly with large pressure amplitude low frequency noise exposure time (p connective tissue. Hence, these results show that in response to large pressure amplitude low frequency noise exposure, rat parotid glands increase their perivasculo-ductal connective tissue.

Novel Therapy for Bone Regeneration in Large Segmental Defects

Science.gov (United States)

2017-12-01

variation . (B) After ComBat (Combing Batches) correction biological variables such as animal age and defect size accounted for largest variation in gene...growth plates), age accounted for more variation than defect size in PC1 (data not shown). This suggests, that age is a dominant factor in bone healing...correlates with histologic changes during fracture repair. J Bone Miner Res 1992; 7:1045-55. 103. Grimston SK, Goldberg DB, Watkins M, Brodt MD, Silva MJ

Repairing rabbit radial defects by combining bone marrow stroma stem cells with bone scaffold material comprising a core-cladding structure.

Science.gov (United States)

Wu, H; Liu, G H; Wu, Q; Yu, B

2015-10-05

We prepared a bone scaffold material comprising a PLGA/β-TCP core and a Type I collagen cladding, and recombined it with bone marrow stroma stem cells (BMSCs) to evaluate its potential for use in bone tissue engineering by in vivo and in vitro experiments. PLGA/β-TCP without a cladding was used for comparison. The adherence rate of the BMSCs to the scaffold was determined by cell counting. Cell proliferation rate was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. The osteogenic capability was evaluated by alkaline phosphatase activity. The scaffold materials were recombined with the BMSCs and implanted into a large segmental rabbit radial defect model to evaluate defect repair. Osteogenesis was assessed in the scaffold materials by histological and double immunofluorescence labeling, etc. The adherence number, proliferation number, and alkaline phosphatase expression of the cells on the bone scaffold material with core-cladding structure were significantly higher than the corresponding values in the PLGA/β-TCP composite scaffold material (P structure completely degraded at the bone defect site and bone formation was completed. The rabbit large sentimental radial defect was successfully repaired. The degradation and osteogenesis rates matched well. The bone scaffold with core-cladding structure exhibited better osteogenic activity and capacity to repair a large segmental bone defect compared to the PLGA/β-TCP composite scaffold. The bone scaffold with core-cladding structure has excellent physical properties and biocompatibility. It is an ideal scaffold material for bone tissue engineering.

Adipose tissue engineering: state of the art, recent advances and innovative approaches.

Science.gov (United States)

Tanzi, Maria Cristina; Farè, Silvia

2009-09-01

Adipose tissue is a highly specialized connective tissue found either in white or brown forms, the white form being the most abundant in adult humans. Loss or damage of white adipose tissue due to aging or pathological conditions needs reconstructive approaches. To date, two main strategies are being investigated for generating functional adipose tissue: autologous tissue/cell transplantation and adipose tissue engineering. Free-fat transplantation rarely achieves sufficient tissue augmentation owing to delayed neovascularization, with subsequent cell necrosis and graft volume shrinkage. Tissue engineering approaches represent, instead, a more suitable alternative for adipose tissue regeneration; they can be performed either with in situ or de novo adipogenesis. In situ adipogenesis or transplantation of encapsulated cells can be useful in healing small-volume defects, whereas restoration of large defects, where vascularization and a rapid volumetric gain are strict requirements, needs de novo strategies with 3D scaffold/filling matrix combinations. For adipose tissue engineering, the use of adult mesenchymal stem cells (both adipose- and bone marrow-derived stem cells) or of preadipocytes is preferred to the use of mature adipocytes, which have low expandability and poor ability for volume retention. This review intends to assemble and describe recent work on this topic, critically presenting successes obtained and drawbacks faced to date.

Large-Scale Molecular Simulations on the Mechanical Response and Failure Behavior of a defective Graphene: Cases of 5-8-5 Defects

Science.gov (United States)

Wang, Shuaiwei; Yang, Baocheng; Yuan, Jinyun; Si, Yubing; Chen, Houyang

2015-10-01

Understanding the effect of defects on mechanical responses and failure behaviors of a graphene membrane is important for its applications. As examples, in this paper, a family of graphene with various 5-8-5 defects are designed and their mechanical responses are investigated by employing molecular dynamics simulations. The dependence of fracture strength and strain as well as Young’s moduli on the nearest neighbor distance and defect types is examined. By introducing the 5-8-5 defects into graphene, the fracture strength and strain become smaller. However, the Young’s moduli of DL (Linear arrangement of repeat unit 5-8-5 defect along zigzag-direction of graphene), DS (a Slope angle between repeat unit 5-8-5 defect and zigzag direction of graphene) and DZ (Zigzag-like 5-8-5 defects) defects in the zigzag direction become larger than those in the pristine graphene in the same direction. A maximum increase of 11.8% of Young’s modulus is obtained. Furthermore, the brittle cracking mechanism is proposed for the graphene with 5-8-5 defects. The present work may provide insights in controlling the mechanical properties by preparing defects in the graphene, and give a full picture for the applications of graphene with defects in flexible electronics and nanodevices.

THORACO - ABDOMINAL FLAP FOR RESURFACING LARGE POST MASTECTOMY DEFECTS IN LOCALLY ADVANCED CA. BREAST

Directory of Open Access Journals (Sweden)

Srinivasa Rao

2015-02-01

Full Text Available Covering of large wounds after mastectomy in locally advanced Ca breast with skin that can withstand radiotherapy is a challenge to the surgeon. Here this study we used a local advancement flap from the adjacent area called Thoraco - A bdominal F la p (TA flap for such giant defects. This is based on superficial and lumbar arteries and is thick to with stand consequent RT . MATERIALS AND METHODS: Of the total 107 cases of LABC 32 had post mastectomy defects of larger than 12 cm and could not be closed by simple approximation. Among the 32 cases 17 cases are covered by split thickness skin grafting. 15 cases are covered by TA flap. These cases are assessed for mean operating time, mean blood loss, post - operative stay, flap necrosis and viability of the f lap after radiotherapy. RESULTS: There is minimal extra time or blood loss in these cases . All the flaps healed well except for small edge necrosis in 4 cases. In all the patients we could start radiotherapy in the fourth week of surgery and all the flaps withstood RT well. After further evaluation probably this can be recommended as procedure for giant post mastectomy defects particularly for those who require RT early

Enamel matrix derivative (Emdogain(R)) for periodontal tissue regeneration in intrabony defects.

Science.gov (United States)

Esposito, Marco; Grusovin, Maria Gabriella; Papanikolaou, Nikolaos; Coulthard, Paul; Worthington, Helen V

2009-10-07

Periodontitis is a chronic infective disease of the gums caused by bacteria present in dental plaque. This condition induces the breakdown of the tooth supporting apparatus until teeth are lost. Surgery may be indicated to arrest disease progression and regenerate lost tissues. Several surgical techniques have been developed to regenerate periodontal tissues including guided tissue regeneration (GTR), bone grafting (BG) and the use of enamel matrix derivative (EMD). EMD is an extract of enamel matrix and contains amelogenins of various molecular weights. Amelogenins are involved in the formation of enamel and periodontal attachment formation during tooth development. To test whether EMD is effective, and to compare EMD versus GTR, and various BG procedures for the treatment of intrabony defects. We searched the Cochrane Oral Health Group Trials Register, CENTRAL, MEDLINE and EMBASE. Several journals were handsearched. No language restrictions were applied. Authors of randomised controlled trials (RCTs) identified, personal contacts and the manufacturer were contacted to identify unpublished trials. Most recent search: February 2009. RCTs on patients affected by periodontitis having intrabony defects of at least 3 mm treated with EMD compared with open flap debridement, GTR and various BG procedures with at least 1 year follow up. The outcome measures considered were: tooth loss, changes in probing attachment levels (PAL), pocket depths (PPD), gingival recessions (REC), bone levels from the bottom of the defects on intraoral radiographs, aesthetics and adverse events. The following time-points were to be evaluated: 1, 5 and 10 years. Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in duplicate and independently by two authors. Results were expressed as random-effects models using mean differences for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals

Correction of bone defects by tissue Engineering Corrección de defectos óseos en el área de Ingeniería tisular

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Simón Yobanny Reyes López

2013-01-01

Full Text Available Currently, bone defects cases represent a major impact on health due to how often they oc­cur because of trauma, fractures, congenital or degenerative diseases. Now, bone implants to large volume are severely restricted because of the diffusion limitations in the interaction with the environment of the host for nutrients, gas exchange and waste disposal. That is why the correction of bone defects has become very important in the field of tissue engi­neering looking to improve clinical strategies for treatment. The purpose of this review is to provide an overview of the development of scaffolds for bone tissue regeneration, showing the progress made in the in vitro and in vivo in recent decadesHoy en día, los defectos óseos representan uno de los casos de mayor impacto en la salud debido a la frecuencia con que éstos ocurren a causa de traumatismos, fracturas, enferme­dades congénitas o degenerativas. En la actualidad, los implantes de tejido óseo de gran volumen se encuentran severamente restringidos a causa de las limitaciones de difusión en la interacción con el ambiente del huésped para los nutrientes, intercambio gaseoso y eliminación de desechos. Es por ello que la corrección de los defectos óseos ha cobrado gran importancia en el área de Ingeniería tisular buscando mejorar las estrategias clínicas para su tratamiento. El propósito de esta revisión es proporcionar un panorama general del desarrollo de andamios para la regeneración de tejido óseo, mostrando los avances logrados en los ensayos in vitro e in vivo en la última década.

Non-unique turbulent boundary layer flows having a moderately large velocity defect: a rational extension of the classical asymptotic theory

Science.gov (United States)

Scheichl, B.; Kluwick, A.

2013-11-01

The classical analysis of turbulent boundary layers in the limit of large Reynolds number Re is characterised by an asymptotically small velocity defect with respect to the external irrotational flow. As an extension of the classical theory, it is shown in the present work that the defect may become moderately large and, in the most general case, independent of Re but still remain small compared to the external streamwise velocity for non-zero pressure gradient boundary layers. That wake-type flow turns out to be characterised by large values of the Rotta-Clauser parameter, serving as an appropriate measure for the defect and hence as a second perturbation parameter besides Re. Most important, it is demonstrated that also this case can be addressed by rigorous asymptotic analysis, which is essentially independent of the choice of a specific Reynolds stress closure. As a salient result of this procedure, transition from the classical small defect to a pronounced wake flow is found to be accompanied by quasi-equilibrium flow, described by a distinguished limit that involves the wall shear stress. This situation is associated with double-valued solutions of the boundary layer equations and an unconventional weak Re-dependence of the external bulk flow—a phenomenon seen to agree well with previous semi-empirical studies and early experimental observations. Numerical computations of the boundary layer flow for various values of Re reproduce these analytical findings with satisfactory agreement.

[Clinical and ossification outcome of custom-made hydroxyapatite prothese for large skull defect].

Science.gov (United States)

Hardy, H; Tollard, E; Derrey, S; Delcampe, P; Péron, J-M; Fréger, P; Proust, F

2012-02-01

Cranioplasty is an everyday concern in neurosurgery, especially in decompressive craniectomy cases. Our surgical team uses custom-made hydroxyapatite implants for large and/or complex defects. Eight patients had a custom-made prosthesis. Each of them has been reviewed by an independent observer. Each patient described his feeling of satisfaction, using a questionnaire, graduated from "A" (really satisfied) to "D" (unsatisfied). Each of them also underwent a CT-scan (helicoidal acquisition, 0.6mm thick for multiplanar reconstruction) to evaluate qualitatively the ossification graduated from "0" (no ossification) to "5" (continuous ossification). Maximal under-prosthetic bone thickness, intra-prosthetic calcic density were also reported. Supervision delay was 43.7 months [6-99 months], average defect surface was 85.5 cm(2) [27.6-137.6 cm(2)], the craniectomy etiologies were intracranial hypertension (seven patients) and calvarial invasion (one patient). Implant tolerance was reparted in "A" score (50%) and "B" score (50%). Concerning ossification, six patients (75%) had a score of "2" or less and two patients had a score of "3" or "4". Hydroxyapatite custom-made implants for cranioplasty appear to be ideal for good aesthetic and tolerance results, but their ossification is hardly analyzed due to the prosthesis density higher than the bone's density. This is why we recommend them for children and in cases of complex defects such as pterion location. Copyright © 2011. Published by Elsevier Masson SAS.

In vitro characterization of a novel tissue engineered based hybridized nano and micro structured collagen implant and its in vivo role on tenoinduction, tenoconduction, tenogenesis and tenointegration.

Science.gov (United States)

Oryan, Ahmad; Moshiri, Ali; Meimandi-Parizi, Abdolhamid

2014-03-01

Surgical reconstruction of large tendon defects is technically demanding. Tissue engineering is a new option. We produced a novel tissue engineered, collagen based, bioimplant and in vitro characterizations of the implant were investigated. In addition, we investigated role of the collagen implant on the healing of a large tendon defect model in rabbits. A two cm length of the left rabbit's Achilles tendon was transected and discarded. The injured tendons of all the rabbits were repaired by Kessler pattern to create and maintain a 2 cm tendon gap. The collagen implant was inserted in the tendon defect of the treatment group (n = 30). The defect area was left intact in the control group (n = 30). The animals were euthanized at 60 days post injury (DPI) and the macro- micro- and nano- morphologies and the biomechanical characteristics of the tendon samples were studied. Differences of P implant properly incorporated with the healing tissue and was replaced by the new tendinous structure which was superior both ultra-structurally and physically than the loose areolar connective tissue regenerated in the control lesions. The results of this study may be valuable in the clinical practice.

Laterality defects in the national birth defects prevention study 1998-2007 birth prevalence and descriptive epidemiology

Science.gov (United States)

Little is known epidemiologically about laterality defects. Using data from the National Birth Defects Prevention Study (NBDPS), a large multi-site case-control study of birth defects, we analyzed prevalence and selected characteristics in children born with laterality defects born from 1998 to 2007...

The long-term behavior of lightweight and heavyweight meshes used to repair abdominal wall defects is determined by the host tissue repair process provoked by the mesh.

Science.gov (United States)

Pascual, Gemma; Hernández-Gascón, Belén; Rodríguez, Marta; Sotomayor, Sandra; Peña, Estefania; Calvo, Begoña; Bellón, Juan M

2012-11-01

Although heavyweight (HW) or lightweight (LW) polypropylene (PP) meshes are widely used for hernia repair, other alternatives have recently appeared. They have the same large-pore structure yet are composed of polytetrafluoroethylene (PTFE). This study compares the long-term (3 and 6 months) behavior of meshes of different pore size (HW compared with LW) and composition (PP compared with PTFE). Partial defects were created in the lateral wall of the abdomen in New Zealand White rabbits and then repaired by the use of a HW or LW PP mesh or a new monofilament, large-pore PTFE mesh (Infinit). At 90 and 180 days after implantation, tissue incorporation, gene and protein expression of neocollagens (reverse transcription-polymerase chain reaction/immunofluorescence), macrophage response (immunohistochemistry), and biomechanical strength were determined. Shrinkage was measured at 90 days. All three meshes induced good host tissue ingrowth, yet the macrophage response was significantly greater in the PTFE implants (P .05). Host collagen deposition is mesh pore size dependent whereas the macrophage response induced is composition dependent with a greater response shown by PTFE. In the long term, macroporous meshes show comparable biomechanical behavior regardless of their pore size or composition. Copyright © 2012 Mosby, Inc. All rights reserved.

Proinflammatory tissue response and recovery of adipokines during 4 days of subcutaneous large-pore microdialysis

DEFF Research Database (Denmark)

Clausen, Trine Schnedler; Kaastrup, Peter; Stallknecht, Bente

2009-01-01

was originally designed for sampling of small molecules but recently the availability of catheters with large-pore membranes has made it possible to recover larger molecules such as adipokines. The present study investigated tissue response towards large-pore microdialysis catheters inserted into human SAT for 4......INTRODUCTION: Subcutaneous adipose tissue (SAT) is increasingly being recognized as a highly active tissue secreting adipokines involved in many physiological and pathophysiological processes. Microdialysis is a technique used for in vivo sampling of interstitial fluid from e.g. SAT. The technique......: Insertion of a large-pore microdialysis catheter into human SAT results in tissue trauma leading to changes in the interstitial concentrations of IL-1beta, IL-6, IL-8, MCP-1, TNF-alpha and adiponectin....

Optimization of Soft Tissue Management, Spacer Design, and Grafting Strategies for Large Segmental Bone Defects using the Chronic Caprine Tibial Defect Model

Science.gov (United States)

2016-12-01

regeneration. The effect of surgical management of the IM demonstrated a significant benefit of scraping to remove the inner layer of the IM (p=0.041). In... Euthanasia is performed 12 weeks after Treatment surgery at which time tibias are harvested and fixed in 10% formalin. Micro CT and histologic analyses of...after euthanasia (after soft tissues are removed) 12 weeks after the grafting procedure. The resulting images are ranked from 1 (greatest bone healing

Printing bone : the application of 3D fiber deposition for bone tissue engineering

NARCIS (Netherlands)

Fedorovich, N.E.

2011-01-01

Bone chips are used by orthopaedic surgeons for treating spinal trauma and to augment large bone defects. A potential alternative to autologous bone is regeneration of bone tissue in the lab by developing hybrid implants consisting of osteogenic (stem) cells seeded on supportive matrices.

Tissue specific mutagenic and carcinogenic responses in NER defective mouse models.

NARCIS (Netherlands)

Wijnhoven, Susan W P; Hoogervorst, Esther M; Waard, Harm de; Horst, Gijsbertus T J van der; Steeg, Harry van

2007-01-01

Several mouse models with defects in genes encoding components of the nucleotide excision repair (NER) pathway have been developed. In NER two different sub-pathways are known, i.e. transcription-coupled repair (TC-NER) and global-genome repair (GG-NER). A defect in one particular NER protein can

Bone tissue engineering and regeneration: from discovery to the clinic--an overview.

Science.gov (United States)

O'Keefe, Regis J; Mao, Jeremy

2011-12-01

A National Institutes of Health sponsored workshop "Bone Tissue Engineering and Regeneration: From Discovery to the Clinic" gathered thought leaders from medicine, science, and industry to determine the state of art in the field and to define the barriers to translating new technologies to novel therapies to treat bone defects. Tissue engineering holds enormous promise to improve human health through prevention of disease and the restoration of healthy tissue functions. Bone tissue engineering, similar to that for other tissues and organs, requires integration of multiple disciplines such as cell biology, stem cells, developmental and molecular biology, biomechanics, biomaterials science, and immunology and transplantation science. Although each of the research areas has undergone enormous advances in last decade, the translation to clinical care and the development of tissue engineering composites to replace human tissues has been limited. Bone, similar to other tissue and organs, has complex structure and functions and requires exquisite interactions between cells, matrices, biomechanical forces, and gene and protein regulatory factors for sustained function. The process of engineering bone, thus, requires a comprehensive approach with broad expertise. Although in vitro and preclinical animal studies have been pursued with a large and diverse collection of scaffolds, cells, and biomolecules, the field of bone tissue engineering remains fragmented up to the point that a clear translational roadmap has yet to emerge. Translation is particularly important for unmet clinical needs such as large segmental defects and medically compromised conditions such as tumor removal and infection sites. Collectively, manuscripts in this volume provide luminary examples toward identification of barriers and strategies for translation of fundamental discoveries into clinical therapeutics. © Mary Ann Liebert, Inc.

Bone Tissue Engineering and Regeneration: From Discovery to the Clinic—An Overview

Science.gov (United States)

2011-01-01

A National Institutes of Health sponsored workshop “Bone Tissue Engineering and Regeneration: From Discovery to the Clinic” gathered thought leaders from medicine, science, and industry to determine the state of art in the field and to define the barriers to translating new technologies to novel therapies to treat bone defects. Tissue engineering holds enormous promise to improve human health through prevention of disease and the restoration of healthy tissue functions. Bone tissue engineering, similar to that for other tissues and organs, requires integration of multiple disciplines such as cell biology, stem cells, developmental and molecular biology, biomechanics, biomaterials science, and immunology and transplantation science. Although each of the research areas has undergone enormous advances in last decade, the translation to clinical care and the development of tissue engineering composites to replace human tissues has been limited. Bone, similar to other tissue and organs, has complex structure and functions and requires exquisite interactions between cells, matrices, biomechanical forces, and gene and protein regulatory factors for sustained function. The process of engineering bone, thus, requires a comprehensive approach with broad expertise. Although in vitro and preclinical animal studies have been pursued with a large and diverse collection of scaffolds, cells, and biomolecules, the field of bone tissue engineering remains fragmented up to the point that a clear translational roadmap has yet to emerge. Translation is particularly important for unmet clinical needs such as large segmental defects and medically compromised conditions such as tumor removal and infection sites. Collectively, manuscripts in this volume provide luminary examples toward identification of barriers and strategies for translation of fundamental discoveries into clinical therapeutics. PMID:21902614

Repair of segmental bone defects in the maxilla by transport disc distraction osteogenesis: Clinical experience with a new device

Science.gov (United States)

Boonzaier, James; Vicatos, George; Hendricks, Rushdi

2015-01-01

The bones of the maxillary complex are vital for normal oro-nasal function and facial cosmetics. Maxillary tumor excision results in large defects that commonly include segments of the alveolar and palatine processes, compromising eating, speech and facial appearance. Unlike the conventional approach to maxillary defect repair by vascularized bone grafting, transport disc distraction osteogenesis (TDDO) stimulates new bone by separating the healing callus, and stimulates growth of surrounding soft tissues as well. Bone formed in this way closely mimics the parent bone in form and internal structure, producing a superior anatomical, functional and cosmetic result. Historically, TDDO has been successfully used to close small horizontal cleft defects in the maxilla, not exceeding 25 mm. Fujioka et al. reported in 2012 that “no bone transporter corresponding to the (large) size of the oro-antral fistula is marketed. The authors report the successful treatment of 4 cases involving alveolar defects of between 25 mm and 80 mm in length. PMID:26389041

Long-Term Results Comparing Xenogeneic Collagen Matrix and Autogenous Connective Tissue Grafts With Coronally Advanced Flaps for Treatment of Dehiscence-Type Recession Defects.

Science.gov (United States)

McGuire, Michael K; Scheyer, E Todd

2016-03-01

Although connective tissue grafts with coronally advanced flaps (CTG + CAF) have been deemed the gold standard for recession defect treatment, to provide adequate recession coverage, the periodontal profession continues to pursue lower-morbidity, patient-preferred substitutes that are more convenient and of unlimited supply. Using a randomized, controlled, and masked contralateral comparison of matched-pair, within-patient recession defects, collagen matrix (CMX) + CAF therapy was compared with CTG + CAF at 6 months and 5 years. The primary efficacy endpoint was percentage of root coverage (RC). Secondary efficacy parameters included width of keratinized tissue (KTw), probing depth (PD), clinical attachment level (CAL), clinician rating of color and texture compared with surrounding tissues, and patient esthetic satisfaction. Seventeen patients were available for the 5-year recall. Mean RC between 6 months and 5 years changed from 89.5% to 77.6% for CMX + CAF test sites and 97.5% to 95.5% for CTG + CAF control sites. KTw averaged >3 mm for both test and control sites at 5 years. PD was equivalent at all time points. The 6-month to 5-year changes for RC, KTw, and PD were not significantly different between therapies. CAL change from 6 months to 5 years was greater for CTG + CAF (0.26 mm) than CMX + CAF (-0.21 mm). Tissue color match to surrounding tissues remained similar for both therapies throughout the study. There was a difference in tissue texture at both 6 months and 5 years, with CMX + CAF sites tending to be "equally firm" and CTG + CAF sites "more firm." Patient satisfaction was high, with no statistical difference in satisfaction between therapies at any time point. When balanced with patient-reported satisfaction, clinical rankings of esthetics, and control and historical RC results reported by other investigators, CMX + CAF appears to present a viable and long-term alternative to traditional CTG + CAF therapy.

Is the stripping technique a tissue-sparing procedure in large simple ovarian cysts in children?

Science.gov (United States)

Arena, Francesco; Romeo, Carmelo; Castagnetti, Marco; Scalfari, GianFranco; Cimador, Marcello; Impellizzeri, Pietro; Villari, Daniela; Zimbaro, Fabrizio; DeGrazia, Enrico

2008-07-01

Stripping of the cystic wall is performed by gynecologists to treat large ovarian cysts. Information in the pediatric population is poor. We prospectively evaluated the pathologic specimens of large ovarian cyst to determine whether the stripping technique is a tissue-sparing procedure even in this age. We evaluated 5 patients. Samples were taken from the intermediate part of the cystic wall and from the layer covering the cyst during excision. The presence of ovarian tissue adjacent to the cyst wall, and the morphological features of the surrounding tissue were both evaluated. Pelvic ultrasound follow-up was also performed. Patients' mean age was 4.5 years (7 days to 12 years). All cysts were removed because all were symptomatic. The mean diameter was 86.6 mm (74-100 mm). Cysts were follicular in 2 cases, serous in other two, and endometriotic in 1 case. Adjacent ovarian tissue was present in 1 of 5 specimens and was approximately 1 to 2 mm in thickness. The layer adjacent to the cystic wall always appeared as normal ovarian tissue. Ultrasound scans at follow-up revealed presence of ovarian tissue. The stripping procedure for large ovarian cyst excision allows to spare the adjacent normal ovarian tissue even in pediatric age because ovarian tissue is rarely excised with the cyst wall during the procedure.

Tissue Distribution of a Therapeutic Monoclonal Antibody Determined by Large Pore Microdialysis.

Science.gov (United States)

Jadhav, Satyawan B; Khaowroongrueng, Vipada; Fueth, Matthias; Otteneder, Michael B; Richter, Wolfgang; Derendorf, Hartmut

2017-09-01

Therapeutic monoclonal antibodies (mAbs) exhibit limited distribution to the target tissues. Determination of target tissue interstitial concentration of mAbs is an important aspect in the assessment of their pharmacokinetic/pharmacodynamics relationship especially for mAbs targeting membrane bound receptors. The pharmacokinetics of R7072, a full length mAb (IgG) targeting human insulin-like growth factor-1 receptor was evaluated following a single intravenous dose at 1, 6.25, and 25 mg/kg in healthy female SCID-beige mice. R7072 showed linear pharmacokinetics over the dose range tested and was characterized by low systemic clearance and long terminal half-life. Furthermore, interstitial distribution of R7072 was evaluated in liver, skin, kidney, and muscle tissues using large pore microdialysis (MD) after intravenous administration of 10 mg/kg dose in mice. The relative recoveries of R7072 were consistent and similar between in vitro and in vivo MD experiments. The tissue and interstitial concentrations were significantly lower compared to serum concentrations and found to be highest in liver and lowest in muscle. The interstitial concentrations of R7072 were approximately 2-fold to 4-fold lower than corresponding total tissue concentrations. Large pore MD appears to be an attractive approach for direct measurement of pharmacologically relevant concentrations of therapeutic mAbs in tissue interstitial fluid. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Adaptive growth factor delivery from a polyelectrolyte coating promotes synergistic bone tissue repair and reconstruction

Science.gov (United States)

Shah, Nisarg J.; Hyder, Md. Nasim; Quadir, Mohiuddin A.; Dorval Courchesne, Noémie-Manuelle; Seeherman, Howard J.; Nevins, Myron; Spector, Myron; Hammond, Paula T.

2014-01-01

Traumatic wounds and congenital defects that require large-scale bone tissue repair have few successful clinical therapies, particularly for craniomaxillofacial defects. Although bioactive materials have demonstrated alternative approaches to tissue repair, an optimized materials system for reproducible, safe, and targeted repair remains elusive. We hypothesized that controlled, rapid bone formation in large, critical-size defects could be induced by simultaneously delivering multiple biological growth factors to the site of the wound. Here, we report an approach for bone repair using a polyelectrolye multilayer coating carrying as little as 200 ng of bone morphogenetic protein-2 and platelet-derived growth factor-BB that were eluted over readily adapted time scales to induce rapid bone repair. Based on electrostatic interactions between the polymer multilayers and growth factors alone, we sustained mitogenic and osteogenic signals with these growth factors in an easily tunable and controlled manner to direct endogenous cell function. To prove the role of this adaptive release system, we applied the polyelectrolyte coating on a well-studied biodegradable poly(lactic-co-glycolic acid) support membrane. The released growth factors directed cellular processes to induce bone repair in a critical-size rat calvaria model. The released growth factors promoted local bone formation that bridged a critical-size defect in the calvaria as early as 2 wk after implantation. Mature, mechanically competent bone regenerated the native calvaria form. Such an approach could be clinically useful and has significant benefits as a synthetic, off-the-shelf, cell-free option for bone tissue repair and restoration. PMID:25136093

Tissue-engineered rhesus monkey nerve grafts for the repair of long ulnar nerve defects: similar outcomes to autologous nerve grafts

Directory of Open Access Journals (Sweden)

Chang-qing Jiang

2016-01-01

Full Text Available Acellular nerve allografts can help preserve normal nerve structure and extracellular matrix composition. These allografts have low immunogenicity and are more readily available than autologous nerves for the repair of long-segment peripheral nerve defects. In this study, we repaired a 40-mm ulnar nerve defect in rhesus monkeys with tissue-engineered peripheral nerve, and compared the outcome with that of autograft. The graft was prepared using a chemical extract from adult rhesus monkeys and seeded with allogeneic Schwann cells. Pathomorphology, electromyogram and immunohistochemistry findings revealed the absence of palmar erosion or ulcers, and that the morphology and elasticity of the hypothenar eminence were normal 5 months postoperatively. There were no significant differences in the mean peak compound muscle action potential, the mean nerve conduction velocity, or the number of neurofilaments between the experimental and control groups. However, outcome was significantly better in the experimental group than in the blank group. These findings suggest that chemically extracted allogeneic nerve seeded with autologous Schwann cells can repair 40-mm ulnar nerve defects in the rhesus monkey. The outcomes are similar to those obtained with autologous nerve graft.

Ready-to-Use Tissue Construct for Military Bone and Cartilage Trauma

Science.gov (United States)

2012-10-01

physiologic hyaline cartilage - osseous transition in massive osteochondral defects in large animals. We will conduct functional outcome analysis, X...10-1-0933 TITLE: Ready-to-Use Tissue Construct for Military Bone and Cartilage Trauma PRINCIPAL INVESTIGATOR: Francis Y. Lee... Cartilage Trauma” addresses the current limitations in treating complex, high-energy musculoskeletal wounds incurred in active combat. High-energy

A tissue engineering solution for segmental defect regeneration in load-bearing long bones.

Science.gov (United States)

Reichert, Johannes C; Cipitria, Amaia; Epari, Devakara R; Saifzadeh, Siamak; Krishnakanth, Pushpanjali; Berner, Arne; Woodruff, Maria A; Schell, Hanna; Mehta, Manav; Schuetz, Michael A; Duda, Georg N; Hutmacher, Dietmar W

2012-07-04

The reconstruction of large defects (>10 mm) in humans usually relies on bone graft transplantation. Limiting factors include availability of graft material, comorbidity, and insufficient integration into the damaged bone. We compare the gold standard autograft with biodegradable composite scaffolds consisting of medical-grade polycaprolactone and tricalcium phosphate combined with autologous bone marrow-derived mesenchymal stem cells (MSCs) or recombinant human bone morphogenetic protein 7 (rhBMP-7). Critical-sized defects in sheep--a model closely resembling human bone formation and structure--were treated with autograft, rhBMP-7, or MSCs. Bridging was observed within 3 months for both the autograft and the rhBMP-7 treatment. After 12 months, biomechanical analysis and microcomputed tomography imaging showed significantly greater bone formation and superior strength for the biomaterial scaffolds loaded with rhBMP-7 compared to the autograft. Axial bone distribution was greater at the interfaces. With rhBMP-7, at 3 months, the radial bone distribution within the scaffolds was homogeneous. At 12 months, however, significantly more bone was found in the scaffold architecture, indicating bone remodeling. Scaffolds alone or with MSC inclusion did not induce levels of bone formation comparable to those of the autograft and rhBMP-7 groups. Applied clinically, this approach using rhBMP-7 could overcome autograft-associated limitations.

Ribosomal and hematopoietic defects in induced pluripotent stem cells derived from Diamond Blackfan anemia patients.

Science.gov (United States)

Garçon, Loïc; Ge, Jingping; Manjunath, Shwetha H; Mills, Jason A; Apicella, Marisa; Parikh, Shefali; Sullivan, Lisa M; Podsakoff, Gregory M; Gadue, Paul; French, Deborah L; Mason, Philip J; Bessler, Monica; Weiss, Mitchell J

2013-08-08

Diamond Blackfan anemia (DBA) is a congenital disorder with erythroid (Ery) hypoplasia and tissue morphogenic abnormalities. Most DBA cases are caused by heterozygous null mutations in genes encoding ribosomal proteins. Understanding how haploinsufficiency of these ubiquitous proteins causes DBA is hampered by limited availability of tissues from affected patients. We generated induced pluripotent stem cells (iPSCs) from fibroblasts of DBA patients carrying mutations in RPS19 and RPL5. Compared with controls, DBA fibroblasts formed iPSCs inefficiently, although we obtained 1 stable clone from each fibroblast line. RPS19-mutated iPSCs exhibited defects in 40S (small) ribosomal subunit assembly and production of 18S ribosomal RNA (rRNA). Upon induced differentiation, the mutant clone exhibited globally impaired hematopoiesis, with the Ery lineage affected most profoundly. RPL5-mutated iPSCs exhibited defective 60S (large) ribosomal subunit assembly, accumulation of 12S pre-rRNA, and impaired erythropoiesis. In both mutant iPSC lines, genetic correction of ribosomal protein deficiency via complementary DNA transfer into the "safe harbor" AAVS1 locus alleviated abnormalities in ribosome biogenesis and hematopoiesis. Our studies show that pathological features of DBA are recapitulated by iPSCs, provide a renewable source of cells to model various tissue defects, and demonstrate proof of principle for genetic correction strategies in patient stem cells.

Tissue vascularization with endothelial-like mesenchymal stromal cells

NARCIS (Netherlands)

Portalska, K.K.

2014-01-01

Although most tissues in the human body have self-renewal capabilities, there are defects, e.g. caused by trauma or disease, which are beyond regenerative potential. Tissue engineering offers a possibility to heal such defects without the necessity of finding a suitable graft donor. While a number

A modular approach to creating large engineered cartilage surfaces.

Science.gov (United States)

Ford, Audrey C; Chui, Wan Fung; Zeng, Anne Y; Nandy, Aditya; Liebenberg, Ellen; Carraro, Carlo; Kazakia, Galateia; Alliston, Tamara; O'Connell, Grace D

2018-01-23

Native articular cartilage has limited capacity to repair itself from focal defects or osteoarthritis. Tissue engineering has provided a promising biological treatment strategy that is currently being evaluated in clinical trials. However, current approaches in translating these techniques to developing large engineered tissues remains a significant challenge. In this study, we present a method for developing large-scale engineered cartilage surfaces through modular fabrication. Modular Engineered Tissue Surfaces (METS) uses the well-known, but largely under-utilized self-adhesion properties of de novo tissue to create large scaffolds with nutrient channels. Compressive mechanical properties were evaluated throughout METS specimens, and the tensile mechanical strength of the bonds between attached constructs was evaluated over time. Raman spectroscopy, biochemical assays, and histology were performed to investigate matrix distribution. Results showed that by Day 14, stable connections had formed between the constructs in the METS samples. By Day 21, bonds were robust enough to form a rigid sheet and continued to increase in size and strength over time. Compressive mechanical properties and glycosaminoglycan (GAG) content of METS and individual constructs increased significantly over time. The METS technique builds on established tissue engineering accomplishments of developing constructs with GAG composition and compressive properties approaching native cartilage. This study demonstrated that modular fabrication is a viable technique for creating large-scale engineered cartilage, which can be broadly applied to many tissue engineering applications and construct geometries. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pms2 suppresses large expansions of the (GAA·TTCn sequence in neuronal tissues.

Directory of Open Access Journals (Sweden)

Rebecka L Bourn

Full Text Available Expanded trinucleotide repeat sequences are the cause of several inherited neurodegenerative diseases. Disease pathogenesis is correlated with several features of somatic instability of these sequences, including further large expansions in postmitotic tissues. The presence of somatic expansions in postmitotic tissues is consistent with DNA repair being a major determinant of somatic instability. Indeed, proteins in the mismatch repair (MMR pathway are required for instability of the expanded (CAG·CTG(n sequence, likely via recognition of intrastrand hairpins by MutSβ. It is not clear if or how MMR would affect instability of disease-causing expanded trinucleotide repeat sequences that adopt secondary structures other than hairpins, such as the triplex/R-loop forming (GAA·TTC(n sequence that causes Friedreich ataxia. We analyzed somatic instability in transgenic mice that carry an expanded (GAA·TTC(n sequence in the context of the human FXN locus and lack the individual MMR proteins Msh2, Msh6 or Pms2. The absence of Msh2 or Msh6 resulted in a dramatic reduction in somatic mutations, indicating that mammalian MMR promotes instability of the (GAA·TTC(n sequence via MutSα. The absence of Pms2 resulted in increased accumulation of large expansions in the nervous system (cerebellum, cerebrum, and dorsal root ganglia but not in non-neuronal tissues (heart and kidney, without affecting the prevalence of contractions. Pms2 suppressed large expansions specifically in tissues showing MutSα-dependent somatic instability, suggesting that they may act on the same lesion or structure associated with the expanded (GAA·TTC(n sequence. We conclude that Pms2 specifically suppresses large expansions of a pathogenic trinucleotide repeat sequence in neuronal tissues, possibly acting independently of the canonical MMR pathway.

Biomaterials with Antibacterial and Osteoinductive Properties to Repair Infected Bone Defects.

Science.gov (United States)

Lu, Haiping; Liu, Yi; Guo, Jing; Wu, Huiling; Wang, Jingxiao; Wu, Gang

2016-03-03

The repair of infected bone defects is still challenging in the fields of orthopedics, oral implantology and maxillofacial surgery. In these cases, the self-healing capacity of bone tissue can be significantly compromised by the large size of bone defects and the potential/active bacterial activity. Infected bone defects are conventionally treated by a systemic/local administration of antibiotics to control infection and a subsequent implantation of bone grafts, such as autografts and allografts. However, these treatment options are time-consuming and usually yield less optimal efficacy. To approach these problems, novel biomaterials with both antibacterial and osteoinductive properties have been developed. The antibacterial property can be conferred by antibiotics and other novel antibacterial biomaterials, such as silver nanoparticles. Bone morphogenetic proteins are used to functionalize the biomaterials with a potent osteoinductive property. By manipulating the carrying modes and release kinetics, these biomaterials are optimized to maximize their antibacterial and osteoinductive functions with minimized cytotoxicity. The findings, in the past decade, have shown a very promising application potential of the novel biomaterials with the dual functions in treating infected bone defects. In this review, we will summarize the current knowledge of novel biomaterials with both antibacterial and osteoinductive properties.

Clinical efficacy of artificial skin combined with vacuum sealing drainage in treating large-area skin defects

Institute of Scientific and Technical Information of China (English)

TANG Jin; GUO Wei-chun; YU Ling; ZHAO Sheng-hao

2010-01-01

Objective: To observe the clinical efficacy of artificial skin combined with vacuum sealing drainage (VSD) in treating large-area skin defects.Methods: Totally 18 patients with skin defects, treated with artificial skin combined with VSD from September 2008to May 2009 in our hospital, were retrospectively analyzed in this study. There were 15 males and 3 females, aged 7-66years, 34.3 years on average. Among them, 10 cases had skin laceration caused by traffic accidents (7 with open fractures), 1 mangled injury, 1 blast injury, 1 stump infection combined with skin defects after amputation and 5 heel ulcers.Results: All skin grafts in 16 cases survived after being controlled by VSD for one time. For the rest 2 patients,one with skin avulsion on the left foot was given median thickness skin grafts after three times of VSD, the other with open fractures in the left tibia and fibula caused by a traffic accident was given free flap transplantation. Skin grafts of both patients survived, with normal color and rich blood supply.Conclusion: Skin grafting in conjunction with artificial skin and VSD is much more effective than traditional dressing treatment and worth wide application in clinic.

Evaluation of defect density by top-view large scale AFM on metamorphic structures grown by MOVPE

Energy Technology Data Exchange (ETDEWEB)

Gocalinska, Agnieszka, E-mail: agnieszka.gocalinska@tyndall.ie; Manganaro, Marina; Dimastrodonato, Valeria; Pelucchi, Emanuele

2015-09-15

Highlights: • Metamorphic buffer layers of In{sub x}Ga{sub 1−x}As were grown by MOVPE and characterised by AFM and TEM. • It was found that AFM provides sufficient information to estimate threading defect density in metamorphic structures, even when significant roughness is present. • When planar-view TEM is lacking, a combination of cross-sectional TEM and large scale AFM can provide good evaluation of the material quality. • It is fast, cheap and non-destructive – can be very useful in development process of complicated structures, requiring multiple test growths and characterisation. - Abstract: We demonstrate an atomic force microscopy based method for estimation of defect density by identification of threading dislocations on a non-flat surface resulting from metamorphic growth. The discussed technique can be applied as an everyday evaluation tool for the quality of epitaxial structures and allow for cost reduction, as it lessens the amount of the transmission electron microscopy analysis required at the early stages of projects. Metamorphic structures with low surface defectivities (below 10{sup 6}) were developed successfully with the application of the technique, proving its usefulness in process optimisation.

[CLINICAL APPLICATION AND EXPERIENCE IN RECONSTRUCTION OF SOFT TISSUE DEFECTS FOLLOWING MALIGNANT TUMOR REMOVAL OF LIMBS USING PERFORATOR PROPELLER FLAPS].

Science.gov (United States)

Zhu, Shan; Liu, Yuanbo; Yu, Shengji; Zang, Mengqing; Zhao, Zhenguo; Xu, Libin; Zhang, Xinxin; Chen, Bo; Ding, Qiang

2016-01-01

To explore the feasibility and technical essentials of soft tissue defect reconstruction following malignant tumor removal of limbs using perforator propeller flaps. Between July 2008 and July 2015, 19 patients with malignant limb tumor underwent defect reconstruction following tumor removal using the perforator propeller flaps. There were 13 males and 6 females with an average age of 53.4 years (range, 20-82 years). The disease duration ranged from 1 to 420 months (mean, 82 months). The tumors located at the thigh in 10 cases, at the leg in 2 cases, at the arm in 1 case, at the forearm in 1 case, around the knee in 2 cases, and around the elbow joint in 3 cases. Totally 23 flaps (from 8 cm x 3 cm to 30 cm x 13 cm in size) were used to reconstruct defects (from 4 cm x 4 cm to 24 cm x 16 cm in size). The potential source arteries included the femoral artery (n = 2), profunda femoral artery (n = 3), superficial circumflex iliac artery (n = 1), lateral circumflex femoral artery (n = 6), superior lateral genicular artery (n = 2), peroneal artery (n = 2), anterior tibial artery (n = 1), brachial artery (n = 4), and radial artery (n = 1). The remaining one was a free style perforator flap. Partial distal flap necrosis occurred in 3 cases after surgery with rotation angles of 180, 150, and 100 degrees respectively, which were reconstructed after debridement using a free-style perforator flap in 1 case and using free skin grafting in the other 2 cases. The other 20 flaps survived completely after surgery. Primary healing of incisions was obtained at the donor and recipient sites. There was no severe complication such as infection, hematoma, and total flap failure. All patients were followed up 3 months to 5 years (mean, 19 months). One patient with malignant melanoma around the elbow joint had tumor recurrence, and underwent secondary tumor resection. The appearance, texture, and color of the flaps were similar to those at the recipient site. For patients with malignant

Embedded defects

International Nuclear Information System (INIS)

Barriola, M.; Vachaspati, T.; Bucher, M.

1994-01-01

We give a prescription for embedding classical solutions and, in particular, topological defects in field theories which are invariant under symmetry groups that are not necessarily simple. After providing examples of embedded defects in field theories based on simple groups, we consider the electroweak model and show that it contains the Z string and a one-parameter family of strings called the W(α) string. It is argued that although the members of this family are gauge equivalent when considered in isolation, each member becomes physically distinct when multistring configurations are considered. We then turn to the issue of stability of embedded defects and demonstrate the instability of a large class of such solutions in the absence of bound states or condensates. The Z string is shown to be unstable for all values of the Higgs boson mass when θ W =π/4. W strings are also shown to be unstable for a large range of parameters. Embedded monopoles suffer from the Brandt-Neri-Coleman instability. Finally, we connect the electroweak string solutions to the sphaleron

Alveolar ridge augmentation by connective tissue grafting using a pouch method and modified connective tissue technique: A prospective study.

Science.gov (United States)

Agarwal, Ashish; Gupta, Narinder Dev

2015-01-01

Localized alveolar ridge defect may create physiological and pathological problems. Developments in surgical techniques have made it simpler to change the configuration of a ridge to create a more aesthetic and more easily cleansable shape. The purpose of this study was to compare the efficacy of alveolar ridge augmentation using a subepithelial connective tissue graft in pouch and modified connective tissue graft technique. In this randomized, double blind, parallel and prospective study, 40 non-smoker individuals with 40 class III alveolar ridge defects in maxillary anterior were randomly divided in two groups. Group I received modified connective tissue graft, while group II were treated with subepithelial connective tissue graft in pouch technique. The defect size was measured in its horizontal and vertical dimension by utilizing a periodontal probe in a stone cast at base line, after 3 months, and 6 months post surgically. Analysis of variance and Bonferroni post-hoc test were used for statistical analysis. A two-tailed P connective tissue graft proposed significantly more improvement as compare to connective tissue graft in pouch.

Platelet rich fibrin in jaw defects

Science.gov (United States)

Nica, Diana; Ianes, Emilia; Pricop, Marius

2016-03-01

Platelet rich fibrin (PRF) is a tissue product of autologous origin abundant in growth factors, widely used in regenerative procedures. Aim of the study: Evaluation of the regenerative effect of PRF added in the bony defects (after tooth removal or after cystectomy) Material and methods: The comparative nonrandomized study included 22 patients divided into 2 groups. The first group (the test group) included 10 patients where the bony defects were treated without any harvesting material. The second group included 12 patients where the bony defects were filled with PRF. The bony defect design was not critical, with one to two walls missing. After the surgeries, a close clinically monitoring was carried out. The selected cases were investigated using both cone beam computer tomography (CBCT) and radiographic techniques after 10 weeks postoperatively. Results: Faster bone regeneration was observed in the bony defects filled with PRF comparing with the not grafted bony defects. Conclusions: PRF added in the bony defects accelerates the bone regeneration. This simplifies the surgical procedures and decreases the economic costs.

Placement of endosseous implant in infected alveolar socket with large fenestration defect: A comparative case report

Directory of Open Access Journals (Sweden)

Balaji Anitha

2010-01-01

Full Text Available Placement of endosseous implants into infected bone is often deferred or avoided due to fear of failure. However, with the development of guided bone regeneration [GBR], some implantologists have reported successful implant placement in infected sockets, even those with fenestration defects. We had the opportunity to compare the osseointegration of an immediate implant placed in an infected site associated with a large buccal fenestration created by the removal of a root stump with that of a delayed implant placed 5 years after extraction. Both implants were placed in the same patient, in the same dental quadrant by the same implantologist. GBR was used with the fenestration defect being filled with demineralized bone graftFNx01 and covered with collagen membraneFNx08. Both implants were osseointegrated and functional when followed up after 12 months.

Nanomaterials for Craniofacial and Dental Tissue Engineering.

Science.gov (United States)

Li, G; Zhou, T; Lin, S; Shi, S; Lin, Y

2017-07-01

Tissue engineering shows great potential as a future treatment for the craniofacial and dental defects caused by trauma, tumor, and other diseases. Due to the biomimetic features and excellent physiochemical properties, nanomaterials are of vital importance in promoting cell growth and stimulating tissue regeneration in tissue engineering. For craniofacial and dental tissue engineering, the frequently used nanomaterials include nanoparticles, nanofibers, nanotubes, and nanosheets. Nanofibers are attractive for cell invasion and proliferation because of their resemblance to extracellular matrix and the presence of large pores, and they have been used as scaffolds in bone, cartilage, and tooth regeneration. Nanotubes and nanoparticles improve the mechanical and chemical properties of scaffold, increase cell attachment and migration, and facilitate tissue regeneration. In addition, nanofibers and nanoparticles are also used as a delivery system to carry the bioactive agent in bone and tooth regeneration, have better control of the release speed of agent upon degradation of the matrix, and promote tissue regeneration. Although applications of nanomaterials in tissue engineering remain in their infancy with numerous challenges to face, the current results indicate that nanomaterials have massive potential in craniofacial and dental tissue engineering.

Absorption and scattering coefficient dependence of laser-Doppler flowmetry models for large tissue volumes

International Nuclear Information System (INIS)

Binzoni, T; Leung, T S; Ruefenacht, D; Delpy, D T

2006-01-01

Based on quasi-elastic scattering theory (and random walk on a lattice approach), a model of laser-Doppler flowmetry (LDF) has been derived which can be applied to measurements in large tissue volumes (e.g. when the interoptode distance is >30 mm). The model holds for a semi-infinite medium and takes into account the transport-corrected scattering coefficient and the absorption coefficient of the tissue, and the scattering coefficient of the red blood cells. The model holds for anisotropic scattering and for multiple scattering of the photons by the moving scatterers of finite size. In particular, it has also been possible to take into account the simultaneous presence of both Brownian and pure translational movements. An analytical and simplified version of the model has also been derived and its validity investigated, for the case of measurements in human skeletal muscle tissue. It is shown that at large optode spacing it is possible to use the simplified model, taking into account only a 'mean' light pathlength, to predict the blood flow related parameters. It is also demonstrated that the 'classical' blood volume parameter, derived from LDF instruments, may not represent the actual blood volume variations when the investigated tissue volume is large. The simplified model does not need knowledge of the tissue optical parameters and thus should allow the development of very simple and cost-effective LDF hardware

Modified classification and single-stage microsurgical repair of posttraumatic infected massive bone defects in lower extremities.

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Yang, Yun-fa; Xu, Zhong-he; Zhang, Guang-ming; Wang, Jian-wei; Hu, Si-wang; Hou, Zhi-qi; Xu, Da-chuan

2013-11-01

Posttraumatic infected massive bone defects in lower extremities are difficult to repair because they frequently exhibit massive bone and/or soft tissue defects, serious bone infection, and excessive scar proliferation. This study aimed to determine whether these defects could be classified and repaired at a single stage. A total of 51 cases of posttraumatic infected massive bone defect in lower extremity were included in this study. They were classified into four types on the basis of the conditions of the bone defects, soft tissue defects, and injured limb length, including Type A (without soft tissue defects), Type B (with soft tissue defects of 10 × 20 cm or less), Type C (with soft tissue defects of 10 × 20 cm or more), and Type D (with the limb shortening of 3 cm or more). Four types of single-stage microsurgical repair protocols were planned accordingly and implemented respectively. These protocols included the following: Protocol A, where vascularized fibular graft was implemented for Type A; Protocol B, where vascularized fibular osteoseptocutaneous graft was implemented for Type B; Protocol C, where vascularized fibular graft and anterior lateral thigh flap were used for Type C; and Protocol D, where limb lengthening and Protocols A, B, or C were used for Type D. There were 12, 33, 4, and 2 cases of Types A, B, C, and D, respectively, according to this classification. During the surgery, three cases of planned Protocol B had to be shifted into Protocol C; however, all microsurgical repairs were completed. With reference to Johner-Wruhs evaluation method, the total percentage of excellent and good results was 82.35% after 6 to 41 months of follow-up. It was concluded that posttraumatic massive bone defects could be accurately classified into four types on the basis of the conditions of bone defects, soft tissue coverage, and injured limb length, and successfully repaired with the single-stage repair protocols after thorough debridement. Thieme Medical

Uninduced adipose-derived stem cells repair the defect of full-thickness hyaline cartilage.

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Zhang, Hai-Ning; Li, Lei; Leng, Ping; Wang, Ying-Zhen; Lv, Cheng-Yu

2009-04-01

To testify the effect of the stem cells derived from the widely distributed fat tissue on repairing full-thickness hyaline cartilage defects. Adipose-derived stem cells (ADSCs) were derived from adipose tissue and cultured in vitro. Twenty-seven New Zealand white rabbits were divided into three groups randomly. The cultured ADSCs mixed with calcium alginate gel were used to fill the full-thickness hyaline cartilage defects created at the patellafemoral joint, and the defects repaired with gel or without treatment served as control groups. After 4, 8 and 12 weeks, the reconstructed tissue was evaluated macroscopically and microscopically. Histological analysis and qualitative scoring were also performed to detect the outcome. Full thickness hyaline cartilage defects were repaired completely with ADSCs-derived tissue. The result was better in ADSCs group than the control ones. The microstructure of reconstructed tissue with ADSCs was similar to that of hyaline cartilage and contained more cells and regular matrix fibers, being better than other groups. Plenty of collagen fibers around cells could be seen under transmission electron microscopy. Statistical analysis revealed a significant difference in comparison with other groups at each time point (t equal to 4.360, P less than 0.01). These results indicate that stem cells derived from mature adipose without induction possess the ability to repair cartilage defects.

Use of perfusion bioreactors and large animal models for long bone tissue engineering.

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Gardel, Leandro S; Serra, Luís A; Reis, Rui L; Gomes, Manuela E

2014-04-01

Tissue engineering and regenerative medicine (TERM) strategies for generation of new bone tissue includes the combined use of autologous or heterologous mesenchymal stem cells (MSC) and three-dimensional (3D) scaffold materials serving as structural support for the cells, that develop into tissue-like substitutes under appropriate in vitro culture conditions. This approach is very important due to the limitations and risks associated with autologous, as well as allogenic bone grafiting procedures currently used. However, the cultivation of osteoprogenitor cells in 3D scaffolds presents several challenges, such as the efficient transport of nutrient and oxygen and removal of waste products from the cells in the interior of the scaffold. In this context, perfusion bioreactor systems are key components for bone TERM, as many recent studies have shown that such systems can provide dynamic environments with enhanced diffusion of nutrients and therefore, perfusion can be used to generate grafts of clinically relevant sizes and shapes. Nevertheless, to determine whether a developed tissue-like substitute conforms to the requirements of biocompatibility, mechanical stability and safety, it must undergo rigorous testing both in vitro and in vivo. Results from in vitro studies can be difficult to extrapolate to the in vivo situation, and for this reason, the use of animal models is often an essential step in the testing of orthopedic implants before clinical use in humans. This review provides an overview of the concepts, advantages, and challenges associated with different types of perfusion bioreactor systems, particularly focusing on systems that may enable the generation of critical size tissue engineered constructs. Furthermore, this review discusses some of the most frequently used animal models, such as sheep and goats, to study the in vivo functionality of bone implant materials, in critical size defects.

Alternatives to Autograft Evaluated in a Rabbit Segmental Bone Defect

Science.gov (United States)

2015-07-09

mesenchymal stem cells for off-the-shelf bone tissue engineering application. Biomaterials 33(9):2656–2672. doi:10.1016/j.biomaterials.2011.12.025 14...segmental bone defects in the rabbit with vascularized tissue engineered bone . Biomaterials 31(6):1171– 1179. doi:10.1016/j.biomaterials.2009.10.043 International Orthopaedics (SICOT) ...ORIGINAL PAPER Alternatives to autograft evaluated in a rabbit segmental bone defect Jennifer S. McDaniel1 & Marcello Pilia1 & Vivek Raut2 & Jeffrey

Rapid and reliable healing of critical size bone defects with genetically modified sheep muscle.

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Liu, F; Ferreira, E; Porter, R M; Glatt, V; Schinhan, M; Shen, Z; Randolph, M A; Kirker-Head, C A; Wehling, C; Vrahas, M S; Evans, C H; Wells, J W

2015-09-21

Large segmental defects in bone fail to heal and remain a clinical problem. Muscle is highly osteogenic, and preliminary data suggest that autologous muscle tissue expressing bone morphogenetic protein-2 (BMP-2) efficiently heals critical size defects in rats. Translation into possible human clinical trials requires, inter alia, demonstration of efficacy in a large animal, such as the sheep. Scale-up is fraught with numerous biological, anatomical, mechanical and structural variables, which cannot be addressed systematically because of cost and other practical issues. For this reason, we developed a translational model enabling us to isolate the biological question of whether sheep muscle, transduced with adenovirus expressing BMP-2, could heal critical size defects in vivo. Initial experiments in athymic rats noted strong healing in only about one-third of animals because of unexpected immune responses to sheep antigens. For this reason, subsequent experiments were performed with Fischer rats under transient immunosuppression. Such experiments confirmed remarkably rapid and reliable healing of the defects in all rats, with bridging by 2 weeks and remodelling as early as 3-4 weeks, despite BMP-2 production only in nanogram quantities and persisting for only 1-3 weeks. By 8 weeks the healed defects contained well-organised new bone with advanced neo-cortication and abundant marrow. Bone mineral content and mechanical strength were close to normal values. These data demonstrate the utility of this model when adapting this technology for bone healing in sheep, as a prelude to human clinical trials.

Defects in large-MISFIT heteroepitaxy

International Nuclear Information System (INIS)

Eaglesham, D.J.; Aindow, M.; Pond, R.C.

1988-01-01

A transmission electron microcopy (TEM) study is presented on GaAs on Si (100) and CdTe on GaAs (100), and the implications for defect nucleation mechanisms are discussed. MOCVD GaAs/Si is shown to grow by island nucleation followed by 3D growth. Single islands are free of inversion domain boundaries (or APBs) implying that a single domain is able to grow over a demi-step on the substrate surface during this 3D growth. MISFIT dislocations are shown to be edge type during island growth, with 60 degrees type being generated at island junctions. The predominant threading dislocations are found to have inclined a/2 left-angle 110 right-angle Burgers vectors. The implied mechanisms for the generation of both MISFIT and threading dislocations are discussed. In MOCVD CdTe/GaAs the microstructure is shown to have a number of qualitatively similar features; in addition, study of this much larger MISFIT system allows the authors to deduce a possible explanation for misorientation effects in these systems

Repair of segmental bone defect using Totally Vitalized tissue engineered bone graft by a combined perfusion seeding and culture system.

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Lin Wang

Full Text Available BACKGROUND: The basic strategy to construct tissue engineered bone graft (TEBG is to combine osteoblastic cells with three dimensional (3D scaffold. Based on this strategy, we proposed the "Totally Vitalized TEBG" (TV-TEBG which was characterized by abundant and homogenously distributed cells with enhanced cell proliferation and differentiation and further investigated its biological performance in repairing segmental bone defect. METHODS: In this study, we constructed the TV-TEBG with the combination of customized flow perfusion seeding/culture system and β-tricalcium phosphate (β-TCP scaffold fabricated by Rapid Prototyping (RP technique. We systemically compared three kinds of TEBG constructed by perfusion seeding and perfusion culture (PSPC method, static seeding and perfusion culture (SSPC method, and static seeding and static culture (SSSC method for their in vitro performance and bone defect healing efficacy with a rabbit model. RESULTS: Our study has demonstrated that TEBG constructed by PSPC method exhibited better biological properties with higher daily D-glucose consumption, increased cell proliferation and differentiation, and better cell distribution, indicating the successful construction of TV-TEBG. After implanted into rabbit radius defects for 12 weeks, PSPC group exerted higher X-ray score close to autograft, much greater mechanical property evidenced by the biomechanical testing and significantly higher new bone formation as shown by histological analysis compared with the other two groups, and eventually obtained favorable healing efficacy of the segmental bone defect that was the closest to autograft transplantation. CONCLUSION: This study demonstrated the feasibility of TV-TEBG construction with combination of perfusion seeding, perfusion culture and RP technique which exerted excellent biological properties. The application of TV-TEBG may become a preferred candidate for segmental bone defect repair in orthopedic and

Dural sinus filling defect: intrasigmoid encephalocele

Science.gov (United States)

Karatag, Ozan; Cosar, Murat; Kizildag, Betul; Sen, Halil Murat

2013-01-01

Filling defects of dural venous sinuses are considered to be a challenging problem especially in case of symptomatic patients. Many lesions have to be ruled out such as sinus thrombosis, arachnoid granulations and tumours. Encephalocele into dural sinus is also a rare cause of these filling defects of dural sinuses. Here, we report an extremely rare case with spontaneous occult invagination of temporal brain tissue into the left sigmoid sinus and accompanying cerebellar ectopia. PMID:24311424

In vivo outcomes of tissue-engineered osteochondral grafts.

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Bal, B Sonny; Rahaman, Mohamed N; Jayabalan, Prakash; Kuroki, Keiichi; Cockrell, Mary K; Yao, Jian Q; Cook, James L

2010-04-01

Tissue-engineered osteochondral grafts have been synthesized from a variety of materials, with some success at repairing chondral defects in animal models. We hypothesized that in tissue-engineered osteochondral grafts synthesized by bonding mesenchymal stem cell-loaded hydrogels to a porous material, the choice of the porous scaffold would affect graft healing to host bone, and the quality of cell restoration at the hyaline cartilage surface. Bone marrow-derived allogeneic mesenchymal stem cells were suspended in hydrogels that were attached to cylinders of porous tantalum metal, allograft bone, or a bioactive glass. The tissue-engineered osteochondral grafts, thus created were implanted into experimental defects in rabbit knees. Subchondral bone restoration, defect fill, bone ingrowth-implant integration, and articular tissue quality were compared between the three subchondral materials at 6 and 12 weeks. Bioactive glass and porous tantalum were superior to bone allograft in integrating to adjacent host bone, regenerating hyaline-like tissue at the graft surface, and expressing type II collagen in the articular cartilage.

Cell-extrinsic defective lymphocyte development in Lmna(-/- mice.

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J Scott Hale

2010-04-01

Full Text Available Mutations in the LMNA gene, which encodes all A-type lamins, result in a variety of human diseases termed laminopathies. Lmna(-/- mice appear normal at birth but become runted as early as 2 weeks of age and develop multiple tissue defects that mimic some aspects of human laminopathies. Lmna(-/- mice also display smaller spleens and thymuses. In this study, we investigated whether altered lymphoid organ sizes are correlated with specific defects in lymphocyte development.Lmna(-/- mice displayed severe age-dependent defects in T and B cell development which coincided with runting. Lmna(-/- bone marrow reconstituted normal T and B cell development in irradiated wild-type recipients, driving generation of functional and self-MHC restricted CD4(+ and CD8(+ T cells. Transplantation of Lmna(-/- neonatal thymus lobes into syngeneic wild-type recipients resulted in good engraftment of thymic tissue and normal thymocyte development.Collectively, these data demonstrate that the severe defects in lymphocyte development that characterize Lmna(-/- mice do not result directly from the loss of A-type lamin function in lymphocytes or thymic stroma. Instead, the immune defects in Lmna(-/- mice likely reflect indirect damage, perhaps resulting from prolonged stress due to the striated muscle dystrophies that occur in these mice.

Peptide-Based Materials for Cartilage Tissue Regeneration.

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Hastar, Nurcan; Arslan, Elif; Guler, Mustafa O; Tekinay, Ayse B

2017-01-01

Cartilaginous tissue requires structural and metabolic support after traumatic or chronic injuries because of its limited capacity for regeneration. However, current techniques for cartilage regeneration are either invasive or ineffective for long-term repair. Developing alternative approaches to regenerate cartilage tissue is needed. Therefore, versatile scaffolds formed by biomaterials are promising tools for cartilage regeneration. Bioactive scaffolds further enhance the utility in a broad range of applications including the treatment of major cartilage defects. This chapter provides an overview of cartilage tissue, tissue defects, and the methods used for regeneration, with emphasis on peptide scaffold materials that can be used to supplement or replace current medical treatment options.

Early reconstruction of bone defect created after initial surgery of a large keratocystic odontogenic tumor: A case report

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Matijević Stevo

2013-01-01

Full Text Available Introduction. Keratocystic odontogenic tumor (KCOT is defined as a benign cystic neoplasm of the jaws of odontogenic origin with a high rate of recurrence. The most lesions occur in the posterior part of the mandible. Treatment of KCOT remains controversial, but the goals of treatment should involve eliminating the potential for recurrence while minimizing surgical morbidity. However, another significant therapeutic problem related to the management of KCOT is an adequate and early reconstruction of the existing jaw defect, as well as appropriate aesthetic and functional rehabilitation of a patient, especially in cases of a very large destruction of the jaws bone. Case report. We presented a 65-year-old female patient with very large KCOT of the mandible. Orthopantomographic radiography showed a very large elliptical multilocular radiolucency, located on the right side of the mandible body and the ascending ramus of the mandible, with radiographic evidence of cortical perforation at the anterior border of the mandibular ramus and the superior border of the alveolar part of the mandible. The surgical treatment included two phases. In the first phase, the tumor was removed by enucleation and additional use of Carnoy solution, performing peripheral ostectomy and excision of the affected overlying mucosa, while in the second phase, restorative surgery of the existing mandibular defect was performed 6 months later. Postoperatively, we did not register any of postoperative complications, nor recurrence within 2 years of the follow-up. Conclusion. Adequate and early reconstruction of the existing jaw defect and appropriate aesthetic and functional rehabilitation of the patient should be the primary goal in the treatment of KCOT, having in mind the need for a long-term post-surgical follow-up.

2-octyl-cyanoacrylate glue for fixation of STSG in genitourinary tissue defects due to Fournier gangrene: a preliminary trial.

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Sivrioğlu, Nazan; Irkören, Saime; Ceylan, Ender; Sonel, Ali Murat; Copçu, Eray

2013-05-01

In these reported cases, we observed the outcomes of skin take and wound healing using 2-octyl-cyanoacrylate glue, which was used as tissue glue in the reconstruction of complex genital skin loss due to fournier gangrene. Fifteen patients with Fournier's gangrene were treated in this study. After initial surgical debridement, all defects were repaired using STSG. In this method a thin layer of 2-octyl-cyanoacrylate was dripped on the recipient site immediately before graft application. All wounds were followed up postoperatively and observed for evidence of graft take, seroma or hematoma formation, drainage, and infection. Patient and physician satisfaction were also determined. Grafts were completely accepted in all fifteen patients. None of the patients had wound infection, seroma, hematoma, or other complications. Use of 2-octyl-cyanoacrylate glue (Glueseal) for STSG fixation in complex genital skin defects after Fournier gangrene may be an acceptable alternative to conventional surgical closure with a good cosmetic outcome. Further studies are needed to confirm our initial success with this approach.

Numerical simulation of fluid field and in vitro three-dimensional fabrication of tissue-engineered bones in a rotating bioreactor and in vivo implantation for repairing segmental bone defects.

Science.gov (United States)

Song, Kedong; Wang, Hai; Zhang, Bowen; Lim, Mayasari; Liu, Yingchao; Liu, Tianqing

2013-03-01

In this paper, two-dimensional flow field simulation was conducted to determine shear stresses and velocity profiles for bone tissue engineering in a rotating wall vessel bioreactor (RWVB). In addition, in vitro three-dimensional fabrication of tissue-engineered bones was carried out in optimized bioreactor conditions, and in vivo implantation using fabricated bones was performed for segmental bone defects of Zelanian rabbits. The distribution of dynamic pressure, total pressure, shear stress, and velocity within the culture chamber was calculated for different scaffold locations. According to the simulation results, the dynamic pressure, velocity, and shear stress around the surface of cell-scaffold construction periodically changed at different locations of the RWVB, which could result in periodical stress stimulation for fabricated tissue constructs. However, overall shear stresses were relatively low, and the fluid velocities were uniform in the bioreactor. Our in vitro experiments showed that the number of cells cultured in the RWVB was five times higher than those cultured in a T-flask. The tissue-engineered bones grew very well in the RWVB. This study demonstrates that stress stimulation in an RWVB can be beneficial for cell/bio-derived bone constructs fabricated in an RWVB, with an application for repairing segmental bone defects.

Comparison of Dorsal Intercostal Artery Perforator Propeller Flaps and Bilateral Rotation Flaps in Reconstruction of Myelomeningocele Defects.

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Tenekeci, Goktekin; Basterzi, Yavuz; Unal, Sakir; Sari, Alper; Demir, Yavuz; Bagdatoglu, Celal; Tasdelen, Bahar

2018-04-09

Bilateral rotation flaps are considered the workhorse flaps in reconstruction of myelomeningocele defects. Since the introduction of perforator flaps in the field of reconstructive surgery, perforator flaps have been used increasingly in the reconstruction of various soft tissue defects all over the body because of their appreciated advantages. The aim of this study was to compare the complications and surgical outcomes between bilateral rotation flaps and dorsal intercostal artery perforator (DICAP) flaps in the soft tissue reconstruction of myelomeningocele defects. Between January 2005-February 2017, we studied 47 patients who underwent reconstruction of myelomeningocele defects. Patient demographics, operative data, and postoperative data were reviewed retrospectively and are included in the study. We found no statistically significant differences in patient demographics and surgical complications between these two groups; this may be due to small sample size. With regard to complications-partial flap necrosis, cerebrospinal fluid (CSF) leakage, necessity for reoperation, and wound infection-DICAP propeller flaps were clinically superior to rotation flaps. Partial flap necrosis was associated with CSF leakage and wound infection, and CSF leakage was associated with wound dehiscence. Although surgical outcomes obtained with DICAP propeller flaps were clinically superior to those obtained with rotation flaps, there was no statistically significant difference between the two patient groups. A well-designed comparative study with adequate sample size is needed. Nonetheless, we suggest using DICAP propeller flaps for reconstruction of large myelomeningocele defects.

Pms2 suppresses large expansions of the (GAA·TTC)n sequence in neuronal tissues.

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Bourn, Rebecka L; De Biase, Irene; Pinto, Ricardo Mouro; Sandi, Chiranjeevi; Al-Mahdawi, Sahar; Pook, Mark A; Bidichandani, Sanjay I

2012-01-01

Expanded trinucleotide repeat sequences are the cause of several inherited neurodegenerative diseases. Disease pathogenesis is correlated with several features of somatic instability of these sequences, including further large expansions in postmitotic tissues. The presence of somatic expansions in postmitotic tissues is consistent with DNA repair being a major determinant of somatic instability. Indeed, proteins in the mismatch repair (MMR) pathway are required for instability of the expanded (CAG·CTG)(n) sequence, likely via recognition of intrastrand hairpins by MutSβ. It is not clear if or how MMR would affect instability of disease-causing expanded trinucleotide repeat sequences that adopt secondary structures other than hairpins, such as the triplex/R-loop forming (GAA·TTC)(n) sequence that causes Friedreich ataxia. We analyzed somatic instability in transgenic mice that carry an expanded (GAA·TTC)(n) sequence in the context of the human FXN locus and lack the individual MMR proteins Msh2, Msh6 or Pms2. The absence of Msh2 or Msh6 resulted in a dramatic reduction in somatic mutations, indicating that mammalian MMR promotes instability of the (GAA·TTC)(n) sequence via MutSα. The absence of Pms2 resulted in increased accumulation of large expansions in the nervous system (cerebellum, cerebrum, and dorsal root ganglia) but not in non-neuronal tissues (heart and kidney), without affecting the prevalence of contractions. Pms2 suppressed large expansions specifically in tissues showing MutSα-dependent somatic instability, suggesting that they may act on the same lesion or structure associated with the expanded (GAA·TTC)(n) sequence. We conclude that Pms2 specifically suppresses large expansions of a pathogenic trinucleotide repeat sequence in neuronal tissues, possibly acting independently of the canonical MMR pathway.

Full-Thickness Skin Grafting with De-Epithelization of the Wound Margin for Finger Defects with Bone or Tendon Exposure

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Jun Hee Lee

2015-05-01

Full Text Available BackgroundFull-thickness skin grafts (FTSGs are generally considered unreliable for coverage of full-thickness finger defects with bone or tendon exposure, and there are few clinical reports of its use in this context. However, animal studies have shown that an FTSG can survive over an avascular area ranging up to 12 mm in diameter. In our experience, the width of the exposed bones or tendons in full-thickness finger defects is <7 mm. Therefore, we covered the bone- or tendon-exposed defects of 16 fingers of 10 patients with FTSGs.MethodsThe surgical objectives were healthy granulation tissue formation in the wound bed, marginal de-epithelization of the normal skin surrounding the defect, preservation of the subdermal plexus of the central graft, and partial excision of the dermis along the graft margin. The donor site was the mastoid for small defects and the groin for large defects.ResultsMost of the grafts (15 of 16 fingers survived without significant surgical complications and achieved satisfactory functional and aesthetic results. Minor complications included partial graft loss in one patient, a minimal extension deformity in two patients, a depression deformity in one patient, and mild hyperpigmentation in four patients.ConclusionsWe observed excellent graft survival with this method with no additional surgical injury of the normal finger, satisfactory functional and aesthetic outcomes, and no need for secondary debulking procedures. Potential disadvantages include an insufficient volume of soft tissue and graft hyperpigmentation. Therefore, FTSGs may be an option for treatment of full-thickness finger defects with bone or tendon exposure.

Biomaterials with Antibacterial and Osteoinductive Properties to Repair Infected Bone Defects

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Haiping Lu

2016-03-01

Full Text Available The repair of infected bone defects is still challenging in the fields of orthopedics, oral implantology and maxillofacial surgery. In these cases, the self-healing capacity of bone tissue can be significantly compromised by the large size of bone defects and the potential/active bacterial activity. Infected bone defects are conventionally treated by a systemic/local administration of antibiotics to control infection and a subsequent implantation of bone grafts, such as autografts and allografts. However, these treatment options are time-consuming and usually yield less optimal efficacy. To approach these problems, novel biomaterials with both antibacterial and osteoinductive properties have been developed. The antibacterial property can be conferred by antibiotics and other novel antibacterial biomaterials, such as silver nanoparticles. Bone morphogenetic proteins are used to functionalize the biomaterials with a potent osteoinductive property. By manipulating the carrying modes and release kinetics, these biomaterials are optimized to maximize their antibacterial and osteoinductive functions with minimized cytotoxicity. The findings, in the past decade, have shown a very promising application potential of the novel biomaterials with the dual functions in treating infected bone defects. In this review, we will summarize the current knowledge of novel biomaterials with both antibacterial and osteoinductive properties.

Engineering vascular development for tissue regeneration

NARCIS (Netherlands)

Rivron, N.C.

2010-01-01

Tissue engineering and regenerative medicine aim at restoring a damaged tissue by recreating in vitro or promoting its regeneratin in vovo. The vasculature is central to these therapies for the irrigation of the defective tissue (oxygen, nutrients or circulating regenerative cells) and as an

Engineering bone tissue from human embryonic stem cells

OpenAIRE

Marolt, Darja; Campos, Iván Marcos; Bhumiratana, Sarindr; Koren, Ana; Petridis, Petros; Zhang, Geping; Spitalnik, Patrice F.; Grayson, Warren L.; Vunjak-Novakovic, Gordana

2012-01-01

In extensive bone defects, tissue damage and hypoxia lead to cell death, resulting in slow and incomplete healing. Human embryonic stem cells (hESC) can give rise to all specialized lineages found in healthy bone and are therefore uniquely suited to aid regeneration of damaged bone. We show that the cultivation of hESC-derived mesenchymal progenitors on 3D osteoconductive scaffolds in bioreactors with medium perfusion leads to the formation of large and compact bone constructs. Notably, the i...

Computational model-informed design and bioprinting of cell-patterned constructs for bone tissue engineering.

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Carlier, Aurélie; Skvortsov, Gözde Akdeniz; Hafezi, Forough; Ferraris, Eleonora; Patterson, Jennifer; Koç, Bahattin; Van Oosterwyck, Hans

2016-05-17

Three-dimensional (3D) bioprinting is a rapidly advancing tissue engineering technology that holds great promise for the regeneration of several tissues, including bone. However, to generate a successful 3D bone tissue engineering construct, additional complexities should be taken into account such as nutrient and oxygen delivery, which is often insufficient after implantation in large bone defects. We propose that a well-designed tissue engineering construct, that is, an implant with a specific spatial pattern of cells in a matrix, will improve the healing outcome. By using a computational model of bone regeneration we show that particular cell patterns in tissue engineering constructs are able to enhance bone regeneration compared to uniform ones. We successfully bioprinted one of the most promising cell-gradient patterns by using cell-laden hydrogels with varying cell densities and observed a high cell viability for three days following the bioprinting process. In summary, we present a novel strategy for the biofabrication of bone tissue engineering constructs by designing cell-gradient patterns based on a computational model of bone regeneration, and successfully bioprinting the chosen design. This integrated approach may increase the success rate of implanted tissue engineering constructs for critical size bone defects and also can find a wider application in the biofabrication of other types of tissue engineering constructs.

3D planning in the reconstruction of maxillofacial defects

NARCIS (Netherlands)

Schepers, Rutger Hendrik

2016-01-01

Resection of a tumor in the upper- or lower jaw often results in a large defect, because with the tumor resection also an adjacent part of the jaw is resected. The most favorable treatment for large defects is the combination of a bony free vascularized graft to reconstruct the defect with implants

The effect of mechanical extension stimulation combined with epithelial cell sorting on outcomes of implanted tissue-engineered muscular urethras.

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Fu, Qiang; Deng, Chen-Liang; Zhao, Ren-Yan; Wang, Ying; Cao, Yilin

2014-01-01

Urethral defects are common and frequent disorders and are difficult to treat. Simple natural or synthetic materials do not provide a satisfactory curative solution for long urethral defects, and urethroplasty with large areas of autologous tissues is limited and might interfere with wound healing. In this study, adipose-derived stem cells were used. These cells can be derived from a wide range of sources, have extensive expansion capability, and were combined with oral mucosal epithelial cells to solve the problem of finding seeding cell sources for producing the tissue-engineered urethras. We also used the synthetic biodegradable polymer poly-glycolic acid (PGA) as a scaffold material to overcome issues such as potential pathogen infections derived from natural materials (such as de-vascular stents or animal-derived collagen) and differing diameters. Furthermore, we used a bioreactor to construct a tissue-engineered epithelial-muscular lumen with a double-layer structure (the epithelial lining and the muscle layer). Through these steps, we used an epithelial-muscular lumen built in vitro to repair defects in a canine urethral defect model (1 cm). Canine urethral reconstruction was successfully achieved based on image analysis and histological techniques at different time points. This study provides a basis for the clinical application of tissue engineering of an epithelial-muscular lumen. Copyright © 2013 Elsevier Ltd. All rights reserved.

Magnetoencephalography signals are influenced by skull defects.

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Lau, S; Flemming, L; Haueisen, J

2014-08-01

Magnetoencephalography (MEG) signals had previously been hypothesized to have negligible sensitivity to skull defects. The objective is to experimentally investigate the influence of conducting skull defects on MEG and EEG signals. A miniaturized electric dipole was implanted in vivo into rabbit brains. Simultaneous recording using 64-channel EEG and 16-channel MEG was conducted, first above the intact skull and then above a skull defect. Skull defects were filled with agar gels, which had been formulated to have tissue-like homogeneous conductivities. The dipole was moved beneath the skull defects, and measurements were taken at regularly spaced points. The EEG signal amplitude increased 2-10 times, whereas the MEG signal amplitude reduced by as much as 20%. The EEG signal amplitude deviated more when the source was under the edge of the defect, whereas the MEG signal amplitude deviated more when the source was central under the defect. The change in MEG field-map topography (relative difference measure, RDM(∗)=0.15) was geometrically related to the skull defect edge. MEG and EEG signals can be substantially affected by skull defects. MEG source modeling requires realistic volume conductor head models that incorporate skull defects. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Polymers in cartilage defect repair of the knee : Current status and future prospects

NARCIS (Netherlands)

Jeuken, R.M.; Roth, A.K.; Peters, R.; van Donkelaar, C.C.; Thies, J.; van Rhijn, L.; Emans, P.

2016-01-01

Cartilage defects in the knee are often seen in young and active patients. There is a need for effective joint preserving treatments in patients suffering from cartilage defects, as untreated defects often lead to osteoarthritis. Within the last two decades, tissue engineering based techniques using

Rehabilitation of post-traumatic total nasal defect using silicone and acrylic resin

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Vikas Aggarwal

2016-01-01

Full Text Available Facial defects resulting from neoplasms, congenital abnormalities or trauma can affect the patient esthetically, psychologically, and even financially. Surgical reconstruction of large facial defects is sometimes not possible and frequently demands prosthetic rehabilitation. For success of such prosthesis, adequate replication of natural anatomy, color matching and blending with tissue interface are important criteria. Variety of materials and retention methods are advocated to achieve a functionally and esthetically acceptable restoration. Silicones are the most commonly used materials because of flexibility, lifelike appearance and ability to be used in combination with acrylic resin which is hard, provides body and helps in achieving retention to the prosthesis by engaging mechanical undercuts. Furthermore, the acrylic portion can be relined easily, thus helping comfortable wear and removal of the prosthesis by patient without traumatizing nasal mucosa. This case report describes time saving and cost effective prosthetic rehabilitation of a patient with total nasal defect using custom sculpted nasal prosthesis made up of silicone elastomer and acrylic resin, which is retained by engaging mechanical undercut and use of biocompatible silicone adhesive.

Nanoparticles for bone tissue engineering.

Science.gov (United States)

Vieira, Sílvia; Vial, Stephanie; Reis, Rui L; Oliveira, J Miguel

2017-05-01

Tissue engineering (TE) envisions the creation of functional substitutes for damaged tissues through integrated solutions, where medical, biological, and engineering principles are combined. Bone regeneration is one of the areas in which designing a model that mimics all tissue properties is still a challenge. The hierarchical structure and high vascularization of bone hampers a TE approach, especially in large bone defects. Nanotechnology can open up a new era for TE, allowing the creation of nanostructures that are comparable in size to those appearing in natural bone. Therefore, nanoengineered systems are now able to more closely mimic the structures observed in naturally occurring systems, and it is also possible to combine several approaches - such as drug delivery and cell labeling - within a single system. This review aims to cover the most recent developments on the use of different nanoparticles for bone TE, with emphasis on their application for scaffolds improvement; drug and gene delivery carriers, and labeling techniques. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:590-611, 2017. © 2017 American Institute of Chemical Engineers.

Development of hybrid scaffolds using ceramic and hydrogel for articular cartilage tissue regeneration.

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Seol, Young-Joon; Park, Ju Young; Jeong, Wonju; Kim, Tae-Ho; Kim, Shin-Yoon; Cho, Dong-Woo

2015-04-01

The regeneration of articular cartilage consisting of hyaline cartilage and hydrogel scaffolds has been generally used in tissue engineering. However, success in in vivo studies has been rarely reported. The hydrogel scaffolds implanted into articular cartilage defects are mechanically unstable and it is difficult for them to integrate with the surrounding native cartilage tissue. Therefore, it is needed to regenerate cartilage and bone tissue simultaneously. We developed hybrid scaffolds with hydrogel scaffolds for cartilage tissue and with ceramic scaffolds for bone tissue. For in vivo study, hybrid scaffolds were press-fitted into osteochondral tissue defects in a rabbit knee joints and the cartilage tissue regeneration in blank, hydrogel scaffolds, and hybrid scaffolds was compared. In 12th week after implantation, the histological and immunohistochemical analyses were conducted to evaluate the cartilage tissue regeneration. In the blank and hydrogel scaffold groups, the defects were filled with fibrous tissues and the implanted hydrogel scaffolds could not maintain their initial position; in the hybrid scaffold group, newly generated cartilage tissues were morphologically similar to native cartilage tissues and were smoothly connected to the surrounding native tissues. This study demonstrates hybrid scaffolds containing hydrogel and ceramic scaffolds can provide mechanical stability to hydrogel scaffolds and enhance cartilage tissue regeneration at the defect site. © 2014 Wiley Periodicals, Inc.

Stem cell homing-based tissue engineering using bioactive materials

Science.gov (United States)

Yu, Yinxian; Sun, Binbin; Yi, Chengqing; Mo, Xiumei

2017-06-01

Tissue engineering focuses on repairing tissue and restoring tissue functions by employing three elements: scaffolds, cells and biochemical signals. In tissue engineering, bioactive material scaffolds have been used to cure tissue and organ defects with stem cell-based therapies being one of the best documented approaches. In the review, different biomaterials which are used in several methods to fabricate tissue engineering scaffolds were explained and show good properties (biocompatibility, biodegradability, and mechanical properties etc.) for cell migration and infiltration. Stem cell homing is a recruitment process for inducing the migration of the systemically transplanted cells, or host cells, to defect sites. The mechanisms and modes of stem cell homing-based tissue engineering can be divided into two types depending on the source of the stem cells: endogenous and exogenous. Exogenous stem cell-based bioactive scaffolds have the challenge of long-term culturing in vitro and for endogenous stem cells the biochemical signal homing recruitment mechanism is not clear yet. Although the stem cell homing-based bioactive scaffolds are attractive candidates for tissue defect therapies, based on in vitro studies and animal tests, there is still a long way before clinical application.

ALK-positive anaplastic large cell lymphoma with soft tissue involvement in a young woman

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Gao KH

2016-07-01

Full Text Available Kehai Gao, Hongtao Li, Caihong Huang, Huazhuang Li, Jun Fang, Chen Tian Department of Orthopaedics, Yidu Central Hospital, Shandong, People’s Republic of China Introduction: Anaplastic large cell lymphoma (ALCL is a type of non-Hodgkin lymphoma that has strong expression of CD30. ALCL can sometimes involve the bone marrow, and in advanced stages, it can produce destructive extranodal lesions. But anaplastic large cell lymphoma kinase (ALK+ ALCL with soft tissue involvement is very rare.Case report: A 35-year-old woman presented with waist pain for over 1 month. The biopsy of soft tissue lesions showed that these cells were positive for ALK-1, CD30, TIA-1, GranzymeB, CD4, CD8, and Ki67 (90%+ and negative for CD3, CD5, CD20, CD10, cytokeratin (CK, TdT, HMB-45, epithelial membrane antigen (EMA, and pan-CK, which identified ALCL. After six cycles of Hyper-CVAD/MA regimen, she achieved partial remission. Three months later, she died due to disease progression.Conclusion: This case illustrates the unusual presentation of ALCL in soft tissue with a bad response to chemotherapy. Because of the tendency for rapid progression, ALCL in young adults with extranodal lesions are often treated with high-grade chemotherapy, such as Hyper-CVAD/MA. Keywords: anaplastic large cell lymphoma, ALK+, soft tissue involvement, Hyper-CVAD/MA

A long-term in vivo investigation on the effects of xenogenous based, electrospun, collagen implants on the healing of experimentally-induced large tendon defects.

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Oryan, A; Moshiri, A; Parizi Meimandi, A; Silver, I A

2013-09-01

This study was designed to investigate the effect of novel 3-dimensional (3-D) collagen implants on the healing of large, experimentally-induced, tendon-defects in rabbits. Forty mature male white New Zealand rabbits were divided randomly into treated and control groups. Two cm of the left Achilles tendon was excised and the gap was spanned by Kessler suture. In the treated group, a novel 3-D collagen implant was inserted between the cut ends of the tendon. No implant was used in the control group. During the course of the experiment the bioelectrical characteristics of the healing and normal tendons of both groups were investigated weekly. At 120 days post injury (DPI), the tendons were dissected and inspected for gross pathology, examined by transmission and scanning electron microscopy, and their biomechanical properties, percentage dry matter and hydroxyproline concentration assessed. The collagen implant significantly improved the bioelectrical characteristics, gross appearance and tissue alignment of the healed, treated tendons, compared to the healed, control scars. It also significantly increased fibrillogenesis, diameter and density of the collagen fibrils, dry matter content, hydroxyproline concentration, maximum load, stiffness, stress and modulus of elasticity of the treated tendons, as compared to the control tendons. Treatment also significantly decreased peri-tendinous adhesions, and improved the hierarchical organization of the tendon from the collagen fibril to fibre-bundle level. 3-D xenogeneic-based collagen implants induced newly regenerated tissue that was ultrastructurally and biomechanically superior to tissue that was regenerated by natural unassisted healing. This type of bioimplant was biocompatible, biodegradable and appeared suitable for clinical use.

Defect detection based on extreme edge of defective region histogram

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Zouhir Wakaf

2018-01-01

Full Text Available Automatic thresholding has been used by many applications in image processing and pattern recognition systems. Specific attention was given during inspection for quality control purposes in various industries like steel processing and textile manufacturing. Automatic thresholding problem has been addressed well by the commonly used Otsu method, which provides suitable results for thresholding images based on a histogram of bimodal distribution. However, the Otsu method fails when the histogram is unimodal or close to unimodal. Defects have different shapes and sizes, ranging from very small to large. The gray-level distributions of the image histogram can vary between unimodal and multimodal. Furthermore, Otsu-revised methods, like the valley-emphasis method and the background histogram mode extents, which overcome the drawbacks of the Otsu method, require preprocessing steps and fail to use the general threshold for multimodal defects. This study proposes a new automatic thresholding algorithm based on the acquisition of the defective region histogram and the selection of its extreme edge as the threshold value to segment all defective objects in the foreground from the image background. To evaluate the proposed defect-detection method, common standard images for experimentation were used. Experimental results of the proposed method show that the proposed method outperforms the current methods in terms of defect detection.

Adaptation of the dermal collagen structure of human skin and scar tissue in response to stretch: An experimental study

NARCIS (Netherlands)

Verhaegen, Pauline D.; Schouten, Hennie J.; Tigchelaar-Gutter, Wikky; van Marle, Jan; van Noorden, Cornelis J.; Middelkoop, Esther; van Zuijlen, Paul P.

2012-01-01

Surgeons are often faced with large defects that are difficult to close. Stretching adjacent skin can facilitate wound closure. In clinical practice, intraoperative stretching is performed in a cyclical or continuous fashion. However, exact mechanisms of tissue adaptation to stretch remain unclear.

Early closure of postinfarction ventricular septal defects.

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Martinelli, Luigi; Dottori, Vincenzo; Caputo, Enrico; Graffigna, Angelo; Pederzolli, Carlo

2003-05-01

According to the guidelines of the American College of Cardiology/American Heart Association early closure of postinfarction septal defects is now a class I indication although it still carries a relevant morbidity and mortality. The operative risk is related both to the critical hemodynamic conditions of the patient and to the technical difficulties posed by the friable tissue of the infarcted area. The most recent techniques involving the use of pericardial patches reinforced by acrylic glue have significantly reduced the hospital mortality. The aim of this study was to discuss the reliability of an aggressive, tissue-sparing surgical approach to this complication. We present a consecutive series of 12 patients operated upon between January 1998 and October 2001 within 12 hours of the onset of clinical evidence of postinfarction septal rupture. Repair was achieved with minimal septal debridement and the use of a large pericardial patch reinforced by a biological glue. Three cases of dehiscence required early reoperation with no hospital mortality. This procedure is technically feasible and allows early aggressive treatment of postinfarction septal rupture with satisfactory results.

Repair of large abdominal wall defects with expanded polytetrafluoroethylene (PTFE).

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Bauer, J J; Salky, B A; Gelernt, I M; Kreel, I

1987-01-01

Most abdominal wall incisional hernias can be repaired by primary closure. However, where the defect is large or there is tension on the closure, the use of a prosthetic material is indicated. Expanded polytetrafluoroethylene (PTFE) patches were used to repair incisional hernias in 28 patients between November 1983 and December 1986. Twelve of these patients (43%) had a prior failure of a primary repair. Reherniation occurred in three patients (10.7%). Wound infections developed in two patients (7.1%), both of whom had existing intestinal stomas, one with an intercurrent pelvic abscess. The prosthetic patch was removed in the patient with the abscess, but the infection was resolved in the other without sequelae. Septic complications did not occur after any operations performed in uncontaminated fields. None of the patients exhibited any undue discomfort, wound pain, erythema, or induration. Complications related to adhesions, erosion of the patch material into the viscera, bowel obstruction, or fistula formation did not occur. Based on this clinical experience, the authors believe that the PTFE patch appears to represent an advance in synthetic abdominal wall substitutes. Images Fig. 1. Fig. 2(left)., Fig. 3(right). PMID:3689012

Levels of PAH-DNA adducts in cord blood and cord tissue and the risk of fetal neural tube defects in a Chinese population.

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Yi, Deqing; Yuan, Yue; Jin, Lei; Zhou, Guodong; Zhu, Huiping; Finnell, Richard H; Ren, Aiguo

2015-01-01

Maternal exposure to polycyclic aromatic hydrocarbons (PAHs) has been shown to be associated with an elevated risk for neural tube defects (NTDs). In the human body, PAHs are bioactivated and the resultant reactive epoxides can covalently bind to DNA to form PAH-DNA adducts, which may, in turn, cause transcription errors, changes in gene expression or altered patterns of apoptosis. During critical developmental phases, these changes can result in abnormal morphogenesis. We aimed to examine the relationship between the levels of PAH-DNA adducts in cord blood and cord tissue and the risk of NTDs. From 2010 to 2012, 60 NTD cases and 60 healthy controls were recruited from a population-based birth defects surveillance system in five counties of Shanxi Province in Northern China, where the emission of PAHs remains one of the highest in the country and PAHs exposure is highly prevalent. PAH-DNA adducts in cord blood of 15 NTD cases and 15 control infants, and in cord tissue of 60 NTD cases and 60 control infants were measured using the (32)P-postlabeling method. PAH-DNA adduct levels in cord blood tend to be higher in the NTD group (28.5 per 10(8) nucleotides) compared with controls (19.7 per 10(8) nucleotides), although the difference was not statistically significant (P=0.377). PAH-DNA adducts in cord tissue were significantly higher in the NTD group (24.6 per 10(6) nucleotides) than in the control group (15.3 per 10(6) nucleotides), P=0.010. A positive dose-response relationship was found between levels of PAH-DNA adducts in cord tissue and the risk of NTDs (P=0.009). When the lowest tertile was used as the referent and potential confounding factors were adjusted for, a 1.03-fold (95% CI, 0.37-2.89) and 2.96-fold (95% CI, 1.16-7.58) increase in the risk of NTDs was observed for fetuses whose cord tissue PAH-DNA adduct levels were in the second and highest tertile, respectively. High levels of PAH-DNA adducts in fetal tissues were associated with increased risks of

Treatment strategy for guided tissue regeneration in various class II furcation defect: Case series

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Pushpendra Kumar Verma

2013-01-01

Full Text Available Periodontal regeneration is a main aspect in the treatment of teeth affected by periodontitis. Periodontal regeneration in furcation areas is quite challenging, especially when it is in interproximal region. There are several techniques used alone or in combination considered to achieve periodontal regeneration, including the bone grafts or substitutes, guided tissue regeneration (GTR, root surface modification, and biological mediators. Many factors may account for variability in response to regenerative therapy in class II furcation. This case series describes the management of class II furcation defect in a mesial interproximal region of a maxillary tooth and other with a buccal class II furcation of mandibular tooth, with the help of surgical intervention including the GTR membrane and bone graft materials. This combined treatment resulted in healthy periodontium with a radiographic evidence of alveolar bone gain in both cases. This case series demonstrates that proper diagnosis, followed by removal of etiological factors and utilizing the combined treatment modalities will restore health and function of the tooth with the severe attachment loss.

Topological defects in extended inflation

International Nuclear Information System (INIS)

Copeland, E.J.; Kolb, E.W.; Chicago Univ., IL; Liddle, A.R.

1990-04-01

We consider the production of topological defects, especially cosmic strings, in extended inflation models. In extended inflation, the Universe passes through a first-order phase transition via bubble percolation, which naturally allows defects to form at the end of inflation. The correlation length, which determines the number density of the defects, is related to the mean size of bubbles when they collide. This mechanism allows a natural combination of inflation and large-scale structure via cosmic strings. 18 refs

Topological defects in extended inflation

International Nuclear Information System (INIS)

Copeland, E.J.; Kolb, E.W.; Liddle, A.R.

1990-01-01

We consider the production of topological defects, especially cosmic strings, in extended-inflation models. In extended inflation, the Universe passes through a first-order phase transition via bubble percolation, which naturally allows defects to form at the end of inflation. The correlation length, which determines the number density of the defects, is related to the mean size of the bubbles when they collide. This mechanism allows a natural combination of inflation and large-scale structure via cosmic strings

Cell-laden hydrogels for osteochondral and cartilage tissue engineering.

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Yang, Jingzhou; Zhang, Yu Shrike; Yue, Kan; Khademhosseini, Ali

2017-07-15

Despite tremendous advances in the field of regenerative medicine, it still remains challenging to repair the osteochondral interface and full-thickness articular cartilage defects. This inefficiency largely originates from the lack of appropriate tissue-engineered artificial matrices that can replace the damaged regions and promote tissue regeneration. Hydrogels are emerging as a promising class of biomaterials for both soft and hard tissue regeneration. Many critical properties of hydrogels, such as mechanical stiffness, elasticity, water content, bioactivity, and degradation, can be rationally designed and conveniently tuned by proper selection of the material and chemistry. Particularly, advances in the development of cell-laden hydrogels have opened up new possibilities for cell therapy. In this article, we describe the problems encountered in this field and review recent progress in designing cell-hydrogel hybrid constructs for promoting the reestablishment of osteochondral/cartilage tissues. Our focus centers on the effects of hydrogel type, cell type, and growth factor delivery on achieving efficient chondrogenesis and osteogenesis. We give our perspective on developing next-generation matrices with improved physical and biological properties for osteochondral/cartilage tissue engineering. We also highlight recent advances in biomanufacturing technologies (e.g. molding, bioprinting, and assembly) for fabrication of hydrogel-based osteochondral and cartilage constructs with complex compositions and microarchitectures to mimic their native counterparts. Despite tremendous advances in the field of regenerative medicine, it still remains challenging to repair the osteochondral interface and full-thickness articular cartilage defects. This inefficiency largely originates from the lack of appropriate tissue-engineered biomaterials that replace the damaged regions and promote tissue regeneration. Cell-laden hydrogel systems have emerged as a promising tissue

Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects

Science.gov (United States)

Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

2016-01-01

A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100-150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1-10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications.

Double-plating of ovine critical sized defects of the tibia: a low morbidity model enabling continuous in vivo monitoring of bone healing

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Pearce Alexandra

2011-09-01

Full Text Available Abstract Background Recent studies using sheep critical sized defect models to test tissue engineered products report high morbidity and complications rates. This study evaluates a large bone defect model in the sheep tibia, stabilized with two, a novel Carbon fibre Poly-ether-ether-ketone (CF-PEEK and a locking compression plate (LCP which could sustain duration for up to 6 month with an acceptable low complication rate. Methods A large bone defect of 3 cm was performed in the mid diaphysis of the right tibia in 33 sheep. The defect was stabilised with the CF - PEEK plate and an LCP. All sheep were supported with slings for 8 weeks after surgery. The study was carried out for 3 months in 6 and for 6 months in 27 animals. Results The surgical procedure could easily be performed in all sheep and continuous in vivo radiographic evaluation of the defect was possible. This long bone critical sized defect model shows with 6.1% a low rate of complications compared with numbers mentioned in the literature. Conclusions This experimental animal model could serve as a standard model in comparative research. A well defined standard model would reduce the number of experimental animals needed in future studies and would therefore add to ethical considerations.

Brain tissue aspiration neural tube defect Aspiração de tecido cerebral em casos de defeitos de fechamento do tubo neural

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Luiz Cesar Peres

2005-09-01

Full Text Available The study aimed to find out how frequent is brain tissue aspiration and if brain tissue heterotopia could be found in the lung of human neural tube defect cases. Histological sections of each lobe of both lungs of 22 fetuses and newborn with neural tube defect were immunostained for glial fibrillary acidic protein (GFAP. There were 15 (68.2% females and 7 (31.8% males. Age ranged from 18 to 40 weeks of gestation (mean= 31.8. Ten (45.5% were stillborn, the same newborn, and 2 (9.1% were abortuses. Diagnosis were: craniorrhachischisis (9 cases, 40.9%, anencephaly (8 cases, 36,4%, ruptured occipital encephalocele and rachischisis (2 cases, 9.1% each, and early amniotic band disruption sequence (1 case, 4.5%. Only one case (4.5% exhibited GFAP positive cells inside bronchioles and alveoli admixed to epithelial amniotic squames. No heterotopic tissue was observed in the lung interstitium. We concluded that aspiration of brain tissue from the amniotic fluid in neural tube defect cases may happen but it is infrequent and heterotopia was not observed.O objetivo do estudo foi identificar qual a freqüência de aspiração de tecido cerebral e a existência de heterotopia nos pulmões de casos humanos de defeito de fechamento do tubo neural através da reação imuno-histoquímica para proteína fibrilar glial ácida (GFAP em cortes histológicos de todos os lobos de ambos os pulmões de 22 casos de fetos e neonatos com defeito de fechamento do tubo neural. Havia 15 casos femininos (68,2% e 7 masculinos (31,8%, com idade gestacional variando de 18 a 40 semanas (média= 31,8, sendo natimortos e neomortos 10 (45,5% cada e 2 (9,1% abortos. Os diagnósticos foram: Craniorraquisquise (9 casos, 40,9%, anencefalia (8 casos, 36,4%, encefalocele occipital rota e raquisquise (2 casos, 9,1% e 1 (4,5%caso de seqüência de disruptura amniótica precoce. Somente 1 caso (4,5% apresentou células positivas dentro de bronquíolos e alvéolos em meio a células epiteliais

Study on nano-structured hydroxyapatite/zirconia stabilized yttria on healing of articular cartilage defect in rabbit

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Amir Sotoudeh

2013-05-01

Full Text Available PURPOSE: Articular Cartilage has limited potential for self-repair and tissue engineering approaches attempt to repair articular cartilage by scaffolds. We hypothesized that the combined hydroxyapatite and zirconia stabilized yttria would enhance the quality of cartilage healing. METHODS: In ten New Zealand white rabbits bilateral full-thickness osteochondral defect, 4 mm in diameter and 3 mm depth, was created on the articular cartilage of the patellar groove of the distal femur. In group I the scaffold was implanted into the right stifle and the same defect was created in the left stifle without any transplant (group II. Specimens were harvested at 12 weeks after implantation, examined histologically for morphologic features, and stained immunohistochemically for type-II collagen. RESULTS: In group I the defect was filled with a white translucent cartilage tissue In contrast, the defects in the group II remained almost empty. In the group I, the defects were mostly filled with hyaline-like cartilage evidenced but defects in group II were filled with fibrous tissue with surface irregularities. Positive immunohistochemical staining of type-II collagen was observed in group I and it was absent in the control group. CONCLUSION: The hydroxyapatite/yttria stabilized zirconia scaffold would be an effective scaffold for cartilage tissue engineering.

Imaging findings in patients with ventral dural defects and herniation of neural tissue

International Nuclear Information System (INIS)

Baur, A.; Staebler, A.; Reiser, M.; Psenner, K.; Hamburger, C.

1997-01-01

The aim of this paper is to describe clinical and imaging findings in three patients with ventral dural defects and herniation of the spinal cord or cauda equina. The literature is reviewed and the clinical, radiological and operative findings are compared. Three patients with ventral dural defects of different etiologies are presented. One patient gave a longstanding history of ankylosing spondylitis, the second patient presents 37 years after spinal trauma, and the third patient presents with spontaneous spinal cord herniation. All patients had typically slowly progressive neurological symptoms with multiple hospitalizations until diagnosis was made. Characteristic findings in postmyelographic CT included a ventral or ventrolateral displacement with deformation of the spinal cord or the cauda equina. Sagittal MRI showed this abrupt and localized anterior deviation of the spinal cord or the cauda equina to the posterior portions of a vertebral body with or without a bony vertebral defect optimally. Additionally, due to the ventral displacement of the spinal cord, the dorsal subarachnoid space was relatively enlarged without evidence of an arachnoid cyst, in all patients. Magnetic resonance imaging and postmyelographic CT can diagnose ventral dural defects with spinal cord herniation or nerve root entrapment. Dural defects must be considered in the presence of neurological symptoms in cases of longstanding ankylosing spondylitis, late sequelae of fractures of vertebral bodies, and without history of spinal trauma or surgery. (orig.). With 3 figs

Acceleration of vascularized bone tissue-engineered constructs in a large animal model combining intrinsic and extrinsic vascularization.

Science.gov (United States)

Weigand, Annika; Beier, Justus P; Hess, Andreas; Gerber, Thomas; Arkudas, Andreas; Horch, Raymund E; Boos, Anja M

2015-05-01

During the last decades, a range of excellent and promising strategies in Bone Tissue Engineering have been developed. However, the remaining major problem is the lack of vascularization. In this study, extrinsic and intrinsic vascularization strategies were combined for acceleration of vascularization. For optimal biomechanical stability of the defect site and simplifying future transition into clinical application, a primary stable and approved nanostructured bone substitute in clinically relevant size was used. An arteriovenous (AV) loop was microsurgically created in sheep and implanted, together with the bone substitute, in either perforated titanium chambers (intrinsic/extrinsic) for different time intervals of up to 18 weeks or isolated Teflon(®) chambers (intrinsic) for 18 weeks. Over time, magnetic resonance imaging and micro-computed tomography (CT) analyses illustrate the dense vascularization arising from the AV loop. The bone substitute was completely interspersed with newly formed tissue after 12 weeks of intrinsic/extrinsic vascularization and after 18 weeks of intrinsic/extrinsic and intrinsic vascularization. Successful matrix change from an inorganic to an organic scaffold could be demonstrated in vascularized areas with scanning electron microscopy and energy dispersive X-ray spectroscopy. Using the intrinsic vascularization method only, the degradation of the scaffold and osteoclastic activity was significantly lower after 18 weeks, compared with 12 and 18 weeks in the combined intrinsic-extrinsic model. Immunohistochemical staining revealed an increase in bone tissue formation over time, without a difference between intrinsic/extrinsic and intrinsic vascularization after 18 weeks. This study presents the combination of extrinsic and intrinsic vascularization strategies for the generation of an axially vascularized bone substitute in clinically relevant size using a large animal model. The additional extrinsic vascularization promotes tissue

Panorama of Reconstruction of Skull Base Defects: From Traditional Open to Endonasal Endoscopic Approaches, from Free Grafts to Microvascular Flaps

Science.gov (United States)

Reyes, Camilo; Mason, Eric; Solares, C. Arturo

2014-01-01

Introduction A substantial body of literature has been devoted to the distinct characteristics and surgical options to repair the skull base. However, the skull base is an anatomically challenging location that requires a three-dimensional reconstruction approach. Furthermore, advances in endoscopic skull base surgery encompass a wide range of surgical pathology, from benign tumors to sinonasal cancer. This has resulted in the creation of wide defects that yield a new challenge in skull base reconstruction. Progress in technology and imaging has made this approach an internationally accepted method to repair these defects. Objectives Discuss historical developments and flaps available for skull base reconstruction. Data Synthesis Free grafts in skull base reconstruction are a viable option in small defects and low-flow leaks. Vascularized flaps pose a distinct advantage in large defects and high-flow leaks. When open techniques are used, free flap reconstruction techniques are often necessary to repair large entry wound defects. Conclusions Reconstruction of skull base defects requires a thorough knowledge of surgical anatomy, disease, and patient risk factors associated with high-flow cerebrospinal fluid leaks. Various reconstruction techniques are available, from free tissue grafting to vascularized flaps. Possible complications that can befall after these procedures need to be considered. Although endonasal techniques are being used with increasing frequency, open techniques are still necessary in selected cases. PMID:25992142

Generating an Engineered Adipose Tissue Flap Using an External Suspension Device.

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Wan, Jinlin; Dong, Ziqing; Lei, Chen; Lu, Feng

2016-07-01

The tissue-engineering chamber technique can generate large volumes of adipose tissue, which provides a potential solution for the complex reconstruction of large soft-tissue defects. However, major drawbacks of this technique are the foreign-body reaction and the volume limitation imposed by the chamber. In this study, the authors developed a novel tissue-engineering method using a specially designed external suspension device that generates an optimized volume of adipose flap and avoids the implantation of foreign material. The rabbits were processed using two different tissue-engineering methods, the external suspension device technique and the traditional tissue-engineering chamber technique. The adipose flaps generated by the external suspension device had a normal adipose tissue structure that was as good as that generated by the traditional tissue-engineering chamber, but the flap volume was much larger. The final volume of the engineered adipose flap grew between weeks 0 and 36 from 5.1 ml to 30.7 ml in the traditional tissue-engineering chamber group and to 80.5 ml in the external suspension device group. During the generation process, there were no marked differences between the two methods in terms of structural and cellular changes of the flap, except that the flaps in the traditional tissue-engineering chamber group had a thicker capsule at the early stage. In addition, the enlarged flaps generated by the external suspension device could be reshaped into specific shapes by the implant chamber. This minimally invasive external suspension device technique can generate large-volume adipose flaps. Combined with a reshaping method, this technique should facilitate clinical application of adipose tissue engineering.

The Role of Three-Dimensional Scaffolds in Treating Long Bone Defects: Evidence from Preclinical and Clinical Literature-A Systematic Review.

Science.gov (United States)

Roffi, Alice; Krishnakumar, Gopal Shankar; Gostynska, Natalia; Kon, Elizaveta; Candrian, Christian; Filardo, Giuseppe

2017-01-01

Long bone defects represent a clinical challenge. Bone tissue engineering (BTE) has been developed to overcome problems associated with conventional methods. The aim of this study was to assess the BTE strategies available in preclinical and clinical settings and the current evidence supporting this approach. A systematic literature screening was performed on PubMed database, searching for both preclinical (only on large animals) and clinical studies. The following string was used: "(Scaffold OR Implant) AND (Long bone defect OR segmental bone defect OR large bone defect OR bone loss defect)." The search retrieved a total of 1573 articles: 51 preclinical and 4 clinical studies were included. The great amount of preclinical papers published over the past few years showed promising findings in terms of radiological and histological evidence. Unfortunately, this in vivo situation is not reflected by a corresponding clinical impact, with few published papers, highly heterogeneous and with small patient populations. Several aspects should be further investigated to translate positive preclinical findings into clinical protocols: the identification of the best biomaterial, with both biological and biomechanical suitable properties, and the selection of the best choice between cells, GFs, or their combination through standardized models to be validated by randomized trials.

Tenonplasty for closing defects during sclerocorneal surgery-A brief review of its anatomy and clinical applications.

Science.gov (United States)

Fries, Fabian N; Suffo, Shady; Daas, Loay; Seitz, Berthold; Fiorentzis, Miltiadis; Viestenz, Arne

2018-01-01

To provide insight into the clinical anatomy of Tenon's capsule and to describe a technique to manage sclerocorneal defects using autologous Tenon's tissue. A thin layer of Tenon's capsule harvested from the patient's own eye is used to seal the defect and act as a scaffold. The Tenon's flap is spread over the defect and held in place by Vicryl sutures. A bandage contact lens is then placed on the eye. Tenon's capsule is composed of thick fibrous tissue with smooth muscle fibers and a thin posterior capsule of orbital fat. It is rich in fibroblasts, which can accelerate wound healing and eventually lead to robust scarring without risk of immunogenicity and without cost. Tenonplasty uses easily-available autologous Tenon's tissue in patients with sclerocorneal defects to preserve globe morphology. The technique is a feasible alternative not limited by the availability of graft tissue. Clin. Anat. 31:72-76, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Mechanisms of Mitochondrial Defects in Gulf War Syndrome

Science.gov (United States)

2011-08-01

alanine. Additional abnormalities included a small fiber neuropathy in 35% (7/20) and cerebral folate defects. Cerebral folate deficiency (CFD) is...CoA ligase, ADP-forming, beta subunit (SUCLA2), Thymidine kinase 2, mitochondrial ( TK2 ), Thymidine phosphorylase (TYMP) may harbor mutations or that...syndrome patients have tissue deficiencies in CoQ10. This abnormality is observed in GWS patients. This defect can be treated with high levels of coenzyme

Animal models for bone tissue engineering and modelling disease

Science.gov (United States)

Griffin, Michelle

2018-01-01

ABSTRACT Tissue engineering and its clinical application, regenerative medicine, are instructing multiple approaches to aid in replacing bone loss after defects caused by trauma or cancer. In such cases, bone formation can be guided by engineered biodegradable and nonbiodegradable scaffolds with clearly defined architectural and mechanical properties informed by evidence-based research. With the ever-increasing expansion of bone tissue engineering and the pioneering research conducted to date, preclinical models are becoming a necessity to allow the engineered products to be translated to the clinic. In addition to creating smart bone scaffolds to mitigate bone loss, the field of tissue engineering and regenerative medicine is exploring methods to treat primary and secondary bone malignancies by creating models that mimic the clinical disease manifestation. This Review gives an overview of the preclinical testing in animal models used to evaluate bone regeneration concepts. Immunosuppressed rodent models have shown to be successful in mimicking bone malignancy via the implantation of human-derived cancer cells, whereas large animal models, including pigs, sheep and goats, are being used to provide an insight into bone formation and the effectiveness of scaffolds in induced tibial or femoral defects, providing clinically relevant similarity to human cases. Despite the recent progress, the successful translation of bone regeneration concepts from the bench to the bedside is rooted in the efforts of different research groups to standardise and validate the preclinical models for bone tissue engineering approaches. PMID:29685995

Formation of topological defects

International Nuclear Information System (INIS)

Vachaspati, T.

1991-01-01

We consider the formation of point and line topological defects (monopoles and strings) from a general point of view by allowing the probability of formation of a defect to vary. To investigate the statistical properties of the defects at formation we give qualitative arguments that are independent of any particular model in which such defects occur. These arguments are substantiated by numerical results in the case of strings and for monopoles in two dimensions. We find that the network of strings at formation undergoes a transition at a certain critical density below which there are no infinite strings and the closed-string (loop) distribution is exponentially suppressed at large lengths. The results are contrasted with the results of statistical arguments applied to a box of strings in dynamical equilibrium. We argue that if point defects were to form with smaller probability, the distance between monopoles and antimonopoles would decrease while the monopole-to-monopole distance would increase. We find that monopoles are always paired with antimonopoles but the pairing becomes clean only when the number density of defects is small. A similar reasoning would also apply to other defects

Study of residue type defect formation mechanism and the effect of advanced defect reduction (ADR) rinse process

Science.gov (United States)

Arima, Hiroshi; Yoshida, Yuichi; Yoshihara, Kosuke; Shibata, Tsuyoshi; Kushida, Yuki; Nakagawa, Hiroki; Nishimura, Yukio; Yamaguchi, Yoshikazu

2009-03-01

Residue type defect is one of yield detractors in lithography process. It is known that occurrence of the residue type defect is dependent on resist development process and the defect is reduced by optimized rinsing condition. However, the defect formation is affected by resist materials and substrate conditions. Therefore, it is necessary to optimize the development process condition by each mask level. Those optimization steps require a large amount of time and effort. The formation mechanism is investigated from viewpoint of both material and process. The defect formation is affected by resist material types, substrate condition and development process condition (D.I.W. rinse step). Optimized resist formulation and new rinse technology significantly reduce the residue type defect.

Clinical and radiographic evaluation of Bio-Gen with biocollagen compared with Bio-Gen with connective tissue in the treatment of class II furcation defects: a randomized clinical trial

Science.gov (United States)

JENABIAN, Niloofar; HAGHANIFAR, Sina; MABOUDI, Avideh; BIJANI, Ali

2013-01-01

Objective Treatment of furcation defects are thought to be challenging. The purpose of this study was to evaluate the clinical and radiographic parameters of Bio-Gen with Biocollagen compared with Bio-Gen with connective tissue in the treatment of Class II furcation defects. Material and Methods In this clinical trial, 24 patients with Class II furcation defect on a buccal or lingual mandibular molar were recruited. After oral hygiene instruction, scaling and root planing and achievement of acceptable plaque control, the patients were randomly chosen to receive either connective tissue and Bio-Gen (case group) or Biocollagen and Bio-Gen (control group). The following parameters were recorded before the first and re-entry surgery (six months later): vertical clinical attachment level (VCAL), gingival index (GI), plaque index (PI), horizontal probing depth (HPD), vertical probing depth (VPD), gingival recession (GR), furcation vertical component (FVC), furcation to alveolar crest (FAC), fornix to base of defect (FBD), and furcation horizontal component (FHC) were calculated at the time of first surgery and during re-entry. A digital periapical radiograph was taken in parallel before first surgery and re-entry. The radiographs were then analyzed by digital subtraction. The differences with p value <0.05 were considered significant. Results Only the mean changes of FAC, FHC, mean of FHC, FBD in re-entry revealed statistically significant differences between the two groups. HPD, VPD, FBD, FAC, and FHC showed statistically significant differences after 6 months in the case group. However, in the control group, statistically significant differences were found in GR and HPD. We did not observe any significant difference in radiographic changes among the two groups. Conclusion The results of this trial indicate that better clinical outcomes can be obtained with connective tissue grafts in combination with bone material compared with a resorbable barrier with bone material

Clinical and radiographic evaluation of Bio-Gen with biocollagen compared with Bio-Gen with connective tissue in the treatment of class II furcation defects: a randomized clinical trial

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Niloofar Jenabian

2013-09-01

Full Text Available OBJECTIVE: Treatment of furcation defects are thought to be challenging. The purpose of this study was to evaluate the clinical and radiographic parameters of Bio-Gen with Biocollagen compared with Bio-Gen with connective tissue in the treatment of Class II furcation defects. MATERIAL AND METHODS: In this clinical trial, 24 patients with Class II furcation defect on a buccal or lingual mandibular molar were recruited. After oral hygiene instruction, scaling and root planing and achievement of acceptable plaque control, the patients were randomly chosen to receive either connective tissue and Bio-Gen (case group or Biocollagen and Bio-Gen (control group. The following parameters were recorded before the first and re-entry surgery (six months later: vertical clinical attachment level (VCAL, gingival index (GI, plaque index (PI, horizontal probing depth (HPD, vertical probing depth (VPD, gingival recession (GR, furcation vertical component (FVC, furcation to alveolar crest (FAC, fornix to base of defect (FBD, and furcation horizontal component (FHC were calculated at the time of first surgery and during re-entry. A digital periapical radiograph was taken in parallel before first surgery and re-entry. The radiographs were then analyzed by digital subtraction. The differences with p value <0.05 were considered significant. RESULTS: Only the mean changes of FAC, FHC, mean of FHC, FBD in re-entry revealed statistically significant differences between the two groups. HPD, VPD, FBD, FAC, and FHC showed statistically significant differences after 6 months in the case group. However, in the control group, statistically significant differences were found in GR and HPD. We did not observe any significant difference in radiographic changes among the two groups. CONCLUSION: The results of this trial indicate that better clinical outcomes can be obtained with connective tissue grafts in combination with bone material compared with a resorbable barrier with bone

Application of concentrated growth factors in reconstruction of bone defects after removal of large jaw cysts: The two cases report

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Mirković Siniša

2015-01-01

Full Text Available Introduction. Coagulation and blood clot formation in bone defects is sometimes followed by retraction of a blood clot and serum extrusion, thus producing peripheral serum-filled spaces between bony wall and coagulum. This can result in a higher incidence of postoperative complications. Stabilization of blood coagulum, which enables successful primary healing, may be accomplished by autotransplantation, allotransplantation, xenotransplantation, or application of autologous platelet concentrate and concentrated growth factors (CGF. Case report. Two patients with large cystic lesions in the upper and lower jaw were presented. In both patients postoperative bony defects were filled with autologous fibrin rich blocks containing CGF. Postoperative course passed uneventfully. Conclusion. Application of fibrin rich blocks containing CGF is one of the possible methods for reconstruction of bone defects. CGF can be applied alone or mixed with a bone graft. The method is relatively simple, without risk of transmissible and allergic diseases and economically feasible.

Intrinsic Osteoinductivity of Porous Titanium Scaffold for Bone Tissue Engineering

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Maryam Tamaddon

2017-01-01

Full Text Available Large bone defects and nonunions are serious complications that are caused by extensive trauma or tumour. As traditional therapies fail to repair these critical-sized defects, tissue engineering scaffolds can be used to regenerate the damaged tissue. Highly porous titanium scaffolds, produced by selective laser sintering with mechanical properties in range of trabecular bone (compressive strength 35 MPa and modulus 73 MPa, can be used in these orthopaedic applications, if a stable mechanical fixation is provided. Hydroxyapatite coatings are generally considered essential and/or beneficial for bone formation; however, debonding of the coatings is one of the main concerns. We hypothesised that the titanium scaffolds have an intrinsic potential to induce bone formation without the need for a hydroxyapatite coating. In this paper, titanium scaffolds coated with hydroxyapatite using electrochemical method were fabricated and osteoinductivity of coated and noncoated scaffolds was compared in vitro. Alizarin Red quantification confirmed osteogenesis independent of coating. Bone formation and ingrowth into the titanium scaffolds were evaluated in sheep stifle joints. The examinations after 3 months revealed 70% bone ingrowth into the scaffold confirming its osteoinductive capacity. It is shown that the developed titanium scaffold has an intrinsic capacity for bone formation and is a suitable scaffold for bone tissue engineering.

Reconstruction of radial bone defect in rat by calcium silicate biomaterials.

Science.gov (United States)

Oryan, Ahmad; Alidadi, Soodeh

2018-05-15

Despite many attempts, an appropriate therapeutic method has not yet been found to enhance bone formation, mechanical strength and structural and functional performances of large bone defects. In the present study, the bone regenerative potential of calcium silicate (CS) biomaterials combined with chitosan (CH) as calcium silicate/chitosan (CSC) scaffold was investigated in a critical radial bone defect in a rat model. The bioimplants were bilaterally implanted in the defects of 20 adult Sprague-Dawley rats. The rats were euthanized and the bone specimens were harvested at the 56th postoperative day. The healed radial bones were evaluated by three-dimensional CT, radiology, histomorphometric analysis, biomechanics, and scanning electron microscopy. The XRD analysis of the CS biomaterial showed its similarity to wollastonite (β-SiCO 3 ). The degradation rate of the CSC scaffold was much higher and it induced milder inflammatory reaction when compared to the CH alone. More bone formation and higher biomechanical performance were observed in the CSC treated group in comparison with the CH treated ones in histological, CT scan and biomechanical examinations. Scanning electron microscopic observation demonstrated the formation of more hydroxyapatite crystals in the defects treated with CSC. This study showed that the CSC biomaterials could be used as proper biodegradable materials in the field of bone reconstruction and tissue engineering. Copyright © 2018 Elsevier Inc. All rights reserved.

Radiation processing of biological tissues for nuclear disaster management

International Nuclear Information System (INIS)

Singh, Rita

2012-01-01

A number of surgical procedures require tissue substitutes to repair or replace damaged or diseased tissues. Biological tissues from human donor like bone, skin, amniotic membrane and other soft tissues can be used for repair or reconstruction of the injured part of the body. Tissues from human donor can be processed and banked for orthopaedic, spinal, trauma and other surgical procedures. Allograft tissues provide an excellent alternative to autografts. The use of allograft tissue avoids the donor site morbidity and reduces the operating time, expense and trauma associated with the acquisition of autografts. Further, allografts have the added advantage of being available in large quantities. This has led to a global increase in allogeneic transplantation and development of tissue banking. However, the risk of infectious disease transmission via tissue allografts is a major concern. Therefore, tissue allografts should be sterilized to make them safe for clinical use. Radiation processing has well appreciated technological advantages and is the most suitable method for sterilization of biological tissues. Radiation processed biological tissues can be provided by the tissue banks for the management of injuries due to a nuclear disaster. A nuclear detonation will result in a large number of casualties due to the heat, blast and radiation effects of the weapon. Skin dressings or skin substitutes like allograft skin, xenograft skin and amniotic membrane can be used for the treatment of thermal burns and radiation induced skin injuries. Bone grafts can be employed for repairing fracture defects, filling in destroyed regions of bone, management of open fractures and joint injuries. Radiation processed tissues have the potential to repair or reconstruct damaged tissues and can be of great assistance in the treatment of injuries due to the nuclear weapon. (author)

Reconstruction of a Post Traumatic Anterior Maxillary Defect by Transport Distraction Osteogenesis.

Science.gov (United States)

Rajkumar, K; Neelakandan, R S; Devadoss, Pradeep; Bandyopadhyay, T K

2017-03-01

Rehabilitation of segmental defects of maxilla presents a reconstructive challenge to obtain an ideal osseous form and height with adequate soft tissue investment. Though variety of prosthetic and surgical reconstructive options like the use of vascularized and non vascularized bone grafts are available they produce less than optimal results. Bone transport distraction is a reliable procedure in various maxillofacial bony defect reconstruction techniques. We describe herein a technique of maxillary bone transport distraction using an indigenously designed, custom made trifocal transport distractor performed in a post traumatic avulsive defect of the anterior maxilla. Transport distraction was successful for anterior maxillary alveolar bony regeneration, with excellent soft tissue cover and vestibular depth, which also helped close an oroantral/oronasal fistula.

Defects at oxide surfaces

CERN Document Server

Thornton, Geoff

2015-01-01

This book presents the basics and characterization of defects at oxide surfaces. It provides a state-of-the-art review of the field, containing information to the various types of surface defects, describes analytical methods to study defects, their chemical activity and the catalytic reactivity of oxides. Numerical simulations of defective structures complete the picture developed. Defects on planar surfaces form the focus of much of the book, although the investigation of powder samples also form an important part. The experimental study of planar surfaces opens the possibility of applying the large armoury of techniques that have been developed over the last half-century to study surfaces in ultra-high vacuum. This enables the acquisition of atomic level data under well-controlled conditions, providing a stringent test of theoretical methods. The latter can then be more reliably applied to systems such as nanoparticles for which accurate methods of characterization of structure and electronic properties ha...

Recent advances in managing septal defects: ventricular septal defects and atrioventricular septal defects [version 1; referees: 3 approved

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P Syamasundar Rao

2018-04-01

Full Text Available This review discusses the management of ventricular septal defects (VSDs and atrioventricular septal defects (AVSDs. There are several types of VSDs: perimembranous, supracristal, atrioventricular septal, and muscular. The indications for closure are moderate to large VSDs with enlarged left atrium and left ventricle or elevated pulmonary artery pressure (or both and a pulmonary-to-systemic flow ratio greater than 2:1. Surgical closure is recommended for large perimembranous VSDs, supracristal VSDs, and VSDs with aortic valve prolapse. Large muscular VSDs may be closed by percutaneous techniques. A large number of devices have been used in the past for VSD occlusion, but currently Amplatzer Muscular VSD Occluder is the only device approved by the US Food and Drug Administration for clinical use. A hybrid approach may be used for large muscular VSDs in small babies. Timely intervention to prevent pulmonary vascular obstructive disease (PVOD is germane in the management of these babies. There are several types of AVSDs: partial, transitional, intermediate, and complete. Complete AVSDs are also classified as balanced and unbalanced. All intermediate and complete balanced AVSDs require surgical correction, and early repair is needed to prevent the onset of PVOD. Surgical correction with closure of atrial septal defect and VSD, along with repair and reconstruction of atrioventricular valves, is recommended. Palliative pulmonary artery banding may be considered in babies weighing less than 5 kg and those with significant co-morbidities. The management of unbalanced AVSDs is more complex, and staged single-ventricle palliation is the common management strategy. However, recent data suggest that achieving two-ventricle repair may be a better option in patients with suitable anatomy, particularly in patients in whom outcomes of single-ventricle palliation are less than optimal. The majority of treatment modes in the management of VSDs and AVSDs are safe

Spontaneous hyaline cartilage regeneration can be induced in an osteochondral defect created in the femoral condyle using a novel double-network hydrogel.

Science.gov (United States)

Yokota, Masashi; Yasuda, Kazunori; Kitamura, Nobuto; Arakaki, Kazunobu; Onodera, Shin; Kurokawa, Takayuki; Gong, Jian-Ping

2011-02-22

Functional repair of articular osteochondral defects remains a major challenge not only in the field of knee surgery but also in tissue regeneration medicine. The purpose is to clarify whether the spontaneous hyaline cartilage regeneration can be induced in a large osteochondral defect created in the femoral condyle by means of implanting a novel double-network (DN) gel at the bottom of the defect. Twenty-five mature rabbits were used in this study. In the bilateral knees of each animal, we created an osteochondral defect having a diameter of 2.4-mm in the medial condyle. Then, in 21 rabbits, we implanted a DN gel plug into a right knee defect so that a vacant space of 1.5-mm depth (in Group I), 2.5-mm depth (in Group II), or 3.5-mm depth (in Group III) was left. In the left knee, we did not apply any treatment to the defect to obtain the control data. All the rabbits were sacrificed at 4 weeks, and the gross and histological evaluations were performed. The remaining 4 rabbits underwent the same treatment as used in Group II, and real-time PCR analysis was performed at 4 weeks. The defect in Group II was filled with a sufficient volume of the hyaline cartilage tissue rich in proteoglycan and type-2 collagen. The Wayne's gross appearance and histology scores showed that Group II was significantly greater than Group I, III, and Control (p hyaline cartilage regeneration can be induced in vivo in an osteochondral defect created in the femoral condyle by means of implanting the DN gel plug at the bottom of the defect so that an approximately 2-mm deep vacant space was intentionally left in the defect. This fact has prompted us to propose an innovative strategy without cell culture to repair osteochondral lesions in the femoral condyle.

Enamel matrix derivative (Emdogain) for periodontal tissue regeneration in intrabony defects. A Cochrane systematic review.

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Esposito, Marco; Grusovin, Maria Gabriella; Papanikolaou, Nikolaos; Coulthard, Paul; Worthington, Helen V

2009-01-01

Periodontitis is a chronic infective disease of the gums caused by bacteria present in dental plaque. This condition induces the breakdown of the tooth supporting apparatus until teeth are lost. Surgery may be indicated to arrest disease progression and regenerate lost tissues. Several surgical techniques have been developed to regenerate periodontal tissues including guided tissue regeneration (GTR), bone grafting (BG) and the use of enamel matrix derivative (EMD). EMD is an extract of enamel matrix and contains amelogenins of various molecular weights. Amelogenins are involved in the formation of enamel and periodontal attachment formation during tooth development. To test whether EMD is effective, and to compare EMD versus GTR, and various BG procedures for the treatment of intrabony defects. The Cochrane Oral Health Group Trials Register, CENTRAL, MEDLINE and EMBASE were searched. Several dental journals were hand searched. No language restrictions were applied. Authors of randomised controlled trials (RCTs) identified, personal contacts and the manufacturer were contacted to identify unpublished trials. The last electronic search was conducted on 4 February 2009. RCTs on patients affected by periodontitis having intrabony defects of at least 3 mm treated with EMD compared with open flap debridement, GTR and various BG procedures with at least 1 year of follow-up. The outcome measures considered were: tooth loss, changes in probing attachment levels (PAL), pocket depths (PPD), gingival recessions (REC), bone levels from the bottom of the defects on intraoral radiographs, aesthetics and adverse events. The following time points were to be evaluated: 1, 5 and 10 years. Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in duplicate and independently by at least two authors. Results were expressed as random-effects models using mean differences for continuous outcomes and risk ratios (RR) for

Functional and Aesthetic Outcome of Reconstruction of Large Oro-Facial Defects Involving the Lip after Tumor Resection

International Nuclear Information System (INIS)

Denewer, A.D.; Setie, A.E.; Hussein, O.A.; Aly, O.F.

2006-01-01

Background: Squamous cell carcinoma of the head and neck is a challenging disease to both surgeons and radiation oncologists due to proximity of many important anatomical structures. Surgery could be curative as these cancers usually metastasize very late by blood stream. Aim of the Work: This work addresses the oncologic, functional and aesthetic factors affecting reconstruction of large orofacial defects involving the lip following tumor resection. Patients and Methods: The study reviews the surgical outcome of one hundred and twelve patients with invasive tumors at. or extending to, the lip(s). treated at the Mansoura University - Surgical Oncology Department, from January 2000 to January 2005. Tumor stage were T 2 (43), T 3 (56) and T 4 (13). Nodal state was N 0 in 80, N 1 in 29 and N 2 in three cases. AJCC stage grouping was II (T 2 N 0 ) in 33 patients. stage III (T 3 N 0 orT 1-3 N 1 ) in 64 cases and stage IV (T 4 due to bone erosion or N 2 ) in 15 cases. The technique used for lip reconstruction was unilateral or bilateral myocutaneous depressor anguli oris flap (MCDAOF) for isolated lip defect (n=63). Bilateral myocutaneous depressor anguli oris (MCDAOF) plus local cervical rotational flap chin defects (n=3). pectorals major myocutaneous pedicled flap for cheek defects involving the lip together with a tongue flap for mucosal reconstruction (n=35). sternocleidomastoid clavicular myo-osseous flap for concomitant mandibular defects (n=] 2). Results: esthetic and functional results are evaluated regarding appearance, oral incompetence, disabling microstomia and eating difficulties. depressor anguli oris reconstruction allowed functioning static and dynamic oral function in all cases in contrast to the Pectorals major flap. there were 18 cases of oral incompetence (46.1%), nine cases of speech difficulty (23%) and five patients with poor cosmetic appearance within the second group total flap loss was not encountered, Partial nap loss affected thirteen

Gene expression profile of the cartilage tissue spontaneously regenerated in vivo by using a novel double-network gel: Comparisons with the normal articular cartilage

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Kurokawa Takayuki

2011-09-01

Full Text Available Abstract Background We have recently found a phenomenon that spontaneous regeneration of a hyaline cartilage-like tissue can be induced in a large osteochondral defect by implanting a double-network (DN hydrogel plug, which was composed of poly-(2-Acrylamido-2-methylpropanesulfonic acid and poly-(N, N'-Dimetyl acrylamide, at the bottom of the defect. The purpose of this study was to clarify gene expression profile of the regenerated tissue in comparison with that of the normal articular cartilage. Methods We created a cylindrical osteochondral defect in the rabbit femoral grooves. Then, we implanted the DN gel plug at the bottom of the defect. At 2 and 4 weeks after surgery, the regenerated tissue was analyzed using DNA microarray and immunohistochemical examinations. Results The gene expression profiles of the regenerated tissues were macroscopically similar to the normal cartilage, but showed some minor differences. The expression degree of COL2A1, COL1A2, COL10A1, DCN, FMOD, SPARC, FLOD2, CHAD, CTGF, and COMP genes was greater in the regenerated tissue than in the normal cartilage. The top 30 genes that expressed 5 times or more in the regenerated tissue as compared with the normal cartilage included type-2 collagen, type-10 collagen, FN, vimentin, COMP, EF1alpha, TFCP2, and GAPDH genes. Conclusions The tissue regenerated by using the DN gel was genetically similar but not completely identical to articular cartilage. The genetic data shown in this study are useful for future studies to identify specific genes involved in spontaneous cartilage regeneration.

Tissue engineering rib with the incorporation of biodegradable polymer cage and BMSCs/decalcified bone: an experimental study in a canine model.

Science.gov (United States)

Tang, Hua; Wu, Bin; Qin, Xiong; Zhang, Lu; Kretlow, Jim; Xu, Zhifei

2013-05-20

The reconstruction of large bone defects, including rib defects, remains a challenge for surgeons. In this study, we used biodegradable polydioxanone (PDO) cages to tissue engineer ribs for the reconstruction of 4cm-long costal defects. PDO sutures were used to weave 6cm long and 1cm diameter cages. Demineralized bone matrix (DBM) which is a xenograft was molded into cuboids and seeded with second passage bone marrow mesenchymal stem cells (BMSCs) that had been osteogenically induced. Two DBM cuboids seeded with BMSCs were put into the PDO cage and used to reconstruct the costal defects. Radiographic examination including 3D reconstruction, histologic examination and mechanical test was performed after 24 postoperative weeks. All the experimental subjects survived. In all groups, the PDO cage had completely degraded after 24 weeks and been replaced by fibrous tissue. Better shape and radian were achieved in PDO cages filled with DBM and BMSCs than in the other two groups (cages alone, or cages filled with acellular DBM cuboids). When the repaired ribs were subjected to an outer force, the ribs in the PDO cage/DBMs/BMSCs group kept their original shape while ribs in the other two groups deformed. In the PDO cage/DBMs/BMSCs groups, we also observed bony union at all the construct interfaces while there was no bony union observed in the other two groups. This result was also confirmed by radiographic and histologic examination. This study demonstrates that biodegradable PDO cage in combination with two short BMSCs/DBM cuboids can repair large rib defects. The satisfactory repair rate suggests that this might be a feasible approach for large bone repair.

Augmentation of bone defect healing using a new biocomposite scaffold: an in vivo study in sheep.

Science.gov (United States)

van der Pol, U; Mathieu, L; Zeiter, S; Bourban, P-E; Zambelli, P-Y; Pearce, S G; Bouré, L P; Pioletti, D P

2010-09-01

Previous studies support resorbable biocomposites made of poly(L-lactic acid) (PLA) and beta-tricalcium phosphate (TCP) produced by supercritical gas foaming as a suitable scaffold for tissue engineering. The present study was undertaken to demonstrate the biocompatibility and osteoconductive properties of such a scaffold in a large animal cancellous bone model. The biocomposite (PLA/TCP) was compared with a currently used beta-TCP bone substitute (ChronOS, Dr. Robert Mathys Foundation), representing a positive control, and empty defects, representing a negative control. Ten defects were created in sheep cancellous bone, three in the distal femur and two in the proximal tibia of each hind limb, with diameters of 5 mm and depths of 15 mm. New bone in-growth (osteoconductivity) and biocompatibility were evaluated using microcomputed tomography and histology at 2, 4 and 12 months after surgery. The in vivo study was validated by the positive control (good bone formation with ChronOS) and the negative control (no healing with the empty defect). A major finding of this study was incorporation of the biocomposite in bone after 12 months. Bone in-growth was observed in the biocomposite scaffold, including its central part. Despite initial fibrous tissue formation observed at 2 and 4 months, but not at 12 months, this initial fibrous tissue does not preclude long-term application of the biocomposite, as demonstrated by its osteointegration after 12 months, as well as the absence of chronic or long-term inflammation at this time point. 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

From DNA lesions to tissue malfunction

International Nuclear Information System (INIS)

Denekamp, J.

1989-01-01

After large doses of radiation, tissues fail to function when the proliferating cells lose their clonogenic ability. This results from unrepaired or misrepaired double strand breaks in the DNA. The lesions are inflicted immediately but there is a variable latent period before tissue damage is expressed. This ranges from a few days in intestine, to weeks in skin, and to months or years in deep visceral tissues, e.g. heart, lung, kidney, spinal cord. The latency relates to the proliferation kinetics of each tissue component. Doses of 10-30 Gy do not cause serious functional defects in differentiated cells, but they prevent successful mitosis in proliferating cells. Thus each tissue continues to function until its differentiated cells are lost by normal wear and tear processes. After a time which relates to the natural lifespan of the differentiated cells, failure to provide replacement cells from the proliferating compartment becomes important and the tissue shows atrophy and eventually a functional deficit. If the radiation exposure is divided into a series of smaller exposures or is given at a low dose-rate, the biochemical repair of DNA is more effective and less damage is observed. After high LET ionizing radiation, e.g. neutrons or α particles, the response is almost linear and is not affected by doserate or fractionation. (author)

Reconstruction of irradiated bone segmental defects with a biomaterial associating MBCP+(R), microstructured collagen membrane and total bone marrow grafting: an experimental study in rabbits.

Science.gov (United States)

Jégoux, Franck; Goyenvalle, Eric; Cognet, Ronan; Malard, Olivier; Moreau, Francoise; Daculsi, Guy; Aguado, Eric

2009-12-15

The bone tissue engineering models used today are still a long way from any oncologic application as immediate postimplantation irradiation would decrease their osteoinductive potential. The aim of this study was to reconstruct a segmental critical size defect in a weight-bearing bone irradiated after implantation. Six white New Zealand rabbits were immediately implanted with a biomaterial associating resorbable collagen membrane EZ(R) filled and micro-macroporous biphasic calcium phosphate granules (MBCP+(R)). After a daily schedule of radiation delivery, and within 4 weeks, a total autologous bone marrow (BM) graft was injected percutaneously into the center of the implant. All the animals were sacrificed at 16 weeks. Successful osseous colonization was found to have bridged the entire length of the defects. Identical distribution of bone ingrowth and residual ceramics at the different levels of the implant suggests that the BM graft plays an osteoinductive role in the center of the defect. Periosteum-like formation was observed at the periphery, with the collagen membrane most likely playing a role. This model succeeded in bridging a large segmental defect in weight-bearing bone with immediate postimplantation fractionated radiation delivery. This has significant implications for the bone tissue engineering approach to patients with cancer-related bone defects.

CARTILAGE CONSTRUCTS ENGINEERED FROM CHONDROCYTES OVEREXPRESSING IGF-I IMPROVE THE REPAIR OF OSTEOCHONDRAL DEFECTS IN A RABBIT MODEL

Science.gov (United States)

Madry, Henning; Kaul, Gunter; Zurakowski, David; Vunjak-Novakovic, Gordana; Cucchiarini, Magali

2015-01-01

Tissue engineering combined with gene therapy is a promising approach for promoting articular cartilage repair. Here, we tested the hypothesis that engineered cartilage with chondrocytes over expressing a human insulin-like growth factor I (IGF-I) gene can enhance the repair of osteochondral defects, in a manner dependent on the duration of cultivation. Genetically modified chondrocytes were cultured on biodegradable polyglycolic acid scaffolds in dynamic flow rotating bioreactors for either 10 or 28 d. The resulting cartilaginous constructs were implanted into osteochondral defects in rabbit knee joints. After 28 weeks of in vivo implantation, immunoreactivity to ß-gal was detectable in the repair tissue of defects that received lacZ constructs. Engineered cartilaginous constructs based on IGF-I-over expressing chondrocytes markedly improved osteochondral repair compared with control (lacZ) constructs. Moreover, IGF-I constructs cultivated for 28 d in vitro significantly promoted osteochondral repair vis-à-vis similar constructs cultivated for 10 d, leading to significantly decreased osteoarthritic changes in the cartilage adjacent to the defects. Hence, the combination of spatially defined overexpression of human IGF-I within a tissue-engineered construct and prolonged bioreactor cultivation resulted in most enhanced articular cartilage repair and reduction of osteoarthritic changes in the cartilage adjacent to the defect. Such genetically enhanced tissue engineering provides a versatile tool to evaluate potential therapeutic genes in vivo and to improve our comprehension of the development of the repair tissue within articular cartilage defects. Insights gained with additional exploration using this model may lead to more effective treatment options for acute cartilage defects. PMID:23588785

Cartilage constructs engineered from chondrocytes overexpressing IGF-I improve the repair of osteochondral defects in a rabbit model

Directory of Open Access Journals (Sweden)

H Madry

2013-04-01

Full Text Available Tissue engineering combined with gene therapy is a promising approach for promoting articular cartilage repair. Here, we tested the hypothesis that engineered cartilage with chondrocytes overexpressing a human insulin-like growth factor I (IGF-I gene can enhance the repair of osteochondral defects, in a manner dependent on the duration of cultivation. Genetically modified chondrocytes were cultured on biodegradable polyglycolic acid scaffolds in dynamic flow rotating bioreactors for either 10 or 28 d. The resulting cartilaginous constructs were implanted into osteochondral defects in rabbit knee joints. After 28 weeks of in vivo implantation, immunoreactivity to ß-gal was detectable in the repair tissue of defects that received lacZ constructs. Engineered cartilaginous constructs based on IGF-I-overexpressing chondrocytes markedly improved osteochondral repair compared with control (lacZ constructs. Moreover, IGF-I constructs cultivated for 28 d in vitro significantly promoted osteochondral repair vis-à-vis similar constructs cultivated for 10 d, leading to significantly decreased osteoarthritic changes in the cartilage adjacent to the defects. Hence, the combination of spatially defined overexpression of human IGF-I within a tissue-engineered construct and prolonged bioreactor cultivation resulted in most enhanced articular cartilage repair and reduction of osteoarthritic changes in the cartilage adjacent to the defect. Such genetically enhanced tissue engineering provides a versatile tool to evaluate potential therapeutic genes in vivo and to improve our comprehension of the development of the repair tissue within articular cartilage defects. Insights gained with additional exploration using this model may lead to more effective treatment options for acute cartilage defects.

Sirenomelia: an epidemiologic study in a large dataset from the International Clearinghouse of Birth Defects Surveillance and Research, and literature review.

Science.gov (United States)

Orioli, Iêda M; Amar, Emmanuelle; Arteaga-Vazquez, Jazmin; Bakker, Marian K; Bianca, Sebastiano; Botto, Lorenzo D; Clementi, Maurizio; Correa, Adolfo; Csaky-Szunyogh, Melinda; Leoncini, Emanuele; Li, Zhu; López-Camelo, Jorge S; Lowry, R Brian; Marengo, Lisa; Martínez-Frías, María-Luisa; Mastroiacovo, Pierpaolo; Morgan, Margery; Pierini, Anna; Ritvanen, Annukka; Scarano, Gioacchino; Szabova, Elena; Castilla, Eduardo E

2011-11-15

Sirenomelia is a very rare limb anomaly in which the normally paired lower limbs are replaced by a single midline limb. This study describes the prevalence, associated malformations, and maternal characteristics among cases with sirenomelia. Data originated from 19 birth defect surveillance system members of the International Clearinghouse for Birth Defects Surveillance and Research, and were reported according to a single pre-established protocol. Cases were clinically evaluated locally and reviewed centrally. A total of 249 cases with sirenomelia were identified among 25,290,172 births, for a prevalence of 0.98 per 100,000, with higher prevalence in the Mexican registry. An increase of sirenomelia prevalence with maternal age less than 20 years was statistically significant. The proportion of twinning was 9%, higher than the 1% expected. Sex was ambiguous in 47% of cases, and no different from expectation in the rest. The proportion of cases born alive, premature, and weighting less than 2,500 g were 47%, 71.2%, and 88.2%, respectively. Half of the cases with sirenomelia also presented with genital, large bowel, and urinary defects. About 10-15% of the cases had lower spinal column defects, single or anomalous umbilical artery, upper limb, cardiac, and central nervous system defects. There was a greater than expected association of sirenomelia with other very rare defects such as bladder exstrophy, cyclopia/holoprosencephaly, and acardia-acephalus. The application of the new biological network analysis approach, including molecular results, to these associated very rare diseases is suggested for future studies. Copyright © 2011 Wiley Periodicals, Inc.

Microsurgical reconstruction of extensive oncological scalp defects

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Ole eGoertz

2015-09-01

Full Text Available While most small to medium defects of the scalp can be covered by local flaps, large defects or complicating factors like a history of radiotherapy often require a microsurgical reconstruction.Several factors need to be considered in such procedures. A sufficient preoperative planning is based on adequate imaging of the malignancy and a multi-disciplinary concept. Several flaps are available for such reconstructions, of which the latissimus dorsi and anterior lateral thigh flaps are the most commonly used ones.In very large defects, combined flaps such as a parascapular / latissimus dorsi flaps can be highly useful or necessary. The most commonly used recipient vessels for microsurgical scalp reconstructions are the superficial temporal vessels, but various other feasible choices exist. If the concomitant veins are not sufficient, the jugular veins represent a safe backup alternative but require a vessel interposition or long pedicle. Postoperative care and patient positioning can be difficult in these patients but can be facilitated by various devices. Overall, microsurgical reconstruction of large scalp defects is a feasible undertaking if the mentioned key factors are taken into account.

The use of large bilobed flap in the management of cheek defect: a ...

African Journals Online (AJOL)

Introduction: bilobed flaps are versatile reconstructive tools which have been used extensively in the management of nasal, shoulder and neck defects. Although its use in the cheek has been reported, it is uncommonly utilized. Case report: This is a case report of a 22yr old lady with traumatic left cheek defect managed with ...

Influence of the gel thickness on in vivo hyaline cartilage regeneration induced by double-network gel implanted at the bottom of a large osteochondral defect: short-term results.

Science.gov (United States)

Matsuda, Hidetoshi; Kitamura, Nobuto; Kurokawa, Takayuki; Arakaki, Kazunobu; Gong, Jian Ping; Kanaya, Fuminori; Yasuda, Kazunori

2013-01-31

A double-network (DN) gel, which is composed of poly(2-acrylamido-2-methylpropanesulfonic acid) and poly(N,N'-dimethyl acrylamide), can induce hyaline cartilage regeneration in vivo in a large osteochondral defect. The purpose of this study was to clarify the influence of the thickness of the implanted DN gel on the induction ability of hyaline cartilage regeneration. Thirty-eight mature rabbits were used in this study. We created an osteochondral defect having a diameter of 4.3-mm in the patellofemoral joint. The knees were randomly divided into 4 groups (Group I: 0.5-mm thick gel, Group II: 1.0-mm thick gel, Group III: 5.0-mm thick gel, and Group IV: untreated control). Animals in each group were further divided into 3 sub-groups depending on the gel implant position (2.0-, 3.0-, or 4.0-mm depth from the articular surface) in the defect. The regenerated tissues were evaluated with the Wayne's gross and histological grading scales and real time PCR analysis of the cartilage marker genes at 4 weeks. According to the total Wayne's score, when the depth of the final vacant space was set at 2.0 mm, the scores in Groups I, II, and III were significantly greater than that Group IV (phyaline cartilage regeneration as the 5.0-mm thick DN gel plug. However, the induction ability of the 0.5-mm thick sheet was significantly lower when compared with the 1.0-mm thick gel sheet. The 1.0-mm DN gel sheet is a promising device to establish a cell-free cartilage regeneration strategy that minimizes bone loss from the gel implantation.

Mesoderm Lineage 3D Tissue Constructs Are Produced at Large-Scale in a 3D Stem Cell Bioprocess.

Science.gov (United States)

Cha, Jae Min; Mantalaris, Athanasios; Jung, Sunyoung; Ji, Yurim; Bang, Oh Young; Bae, Hojae

2017-09-01

Various studies have presented different approaches to direct pluripotent stem cell differentiation such as applying defined sets of exogenous biochemical signals and genetic/epigenetic modifications. Although differentiation to target lineages can be successfully regulated, such conventional methods are often complicated, laborious, and not cost-effective to be employed to the large-scale production of 3D stem cell-based tissue constructs. A 3D-culture platform that could realize the large-scale production of mesoderm lineage tissue constructs from embryonic stem cells (ESCs) is developed. ESCs are cultured using our previously established 3D-bioprocess platform which is amenable to mass-production of 3D ESC-based tissue constructs. Hepatocarcinoma cell line conditioned medium is introduced to the large-scale 3D culture to provide a specific biomolecular microenvironment to mimic in vivo mesoderm formation process. After 5 days of spontaneous differentiation period, the resulting 3D tissue constructs are composed of multipotent mesodermal progenitor cells verified by gene and molecular expression profiles. Subsequently the optimal time points to trigger terminal differentiation towards cardiomyogenesis or osteogenesis from the mesodermal tissue constructs is found. A simple and affordable 3D ESC-bioprocess that can reach the scalable production of mesoderm origin tissues with significantly improved correspondent tissue properties is demonstrated. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Arthroscopic treatment of chondral defects in the hip: AMIC, MACI, microfragmented adipose tissue transplantation (MATT and other options

Directory of Open Access Journals (Sweden)

Jannelli Eugenio

2017-01-01

Full Text Available Chondral lesions are currently considered in the hip as a consequence of trauma, osteonecrosis, dysplasia, labral tears, loose bodies, dislocation, previous slipped capital femoral epiphysis and Femoro-Acetabular-Impingement (FAI. The management of chondral lesions is debated and several techniques are described. The physical examination must be carefully performed, followed by radiographs and magnetic resonance imaging (MRI. Differential diagnosis with other pathologies must be considered. Debridement is indicated in patients younger than 50 years with a chondropathy of 1st or 2nd degree. Microfractures are indicated in patients younger than 50 years with a chondropathy of 3rd or 4th degree less than 2 cm2. Matrix-Induced Autologous Chondrocyte Implantation (MACI and Autologous Matrix-Induced Chondrogenesis (AMIC procedures are indicated in patients with full-thickness symptomatic 3rd–4th degree chondral defects, extended 2 cm2 or more. The AMIC procedure has the advantage of a one-step procedure and much less expense. Microfragmented adipose tissue transplantation (MATT is indicated for the treatment of delamination and 1st and 2nd degree chondral lesions, regardless of the age of the patient. Chondral defects are effective when the joint space is not compromised. When the Tonnis classification is two or greater, treatment of chondral lesions should be considered ineffective.

Hard tissue regeneration using bone substitutes: an update on innovations in materials.

Science.gov (United States)

Sarkar, Swapan Kumar; Lee, Byong Taek

2015-05-01

Bone is a unique organ composed of mineralized hard tissue, unlike any other body part. The unique manner in which bone can constantly undergo self-remodeling has created interesting clinical approaches to the healing of damaged bone. Healing of large bone defects is achieved using implant materials that gradually integrate with the body after healing is completed. Such strategies require a multidisciplinary approach by material scientists, biological scientists, and clinicians. Development of materials for bone healing and exploration of the interactions thereof with the body are active research areas. In this review, we explore ongoing developments in the creation of materials for regenerating hard tissues.

Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects

OpenAIRE

Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

2016-01-01

A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100?150?MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110?MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1?10?MPa compressive...

Use of cyanoacrylate as barrier in guided tissue regeneration in class II furcation defects

Directory of Open Access Journals (Sweden)

Carmen L Mueller Storrer

2014-01-01

Full Text Available The guided bone regeneration (GBR is a technique that uses resorbable and non-resorbable membranes in association with other filling biomaterials. GBR is one of the optional treatments for therapy of class II furcation defects. The current case report evaluates clinically and radiographically the use of the cyanoacrylate membrane (Glubran ®2 associated with organic bovine bone (GenOx for the treatment of vestibular class II furcation defect on the lower left molar. Conclusion: The GBR is an option in the treatment of vestibular class II furcation defects and cyanoacrylate surgical glue, acting as a mechanic barrier and providing an efficient stability for the graft.

Little string origin of surface defects

Energy Technology Data Exchange (ETDEWEB)

Haouzi, Nathan; Schmid, Christian [Center for Theoretical Physics, University of California, Berkeley,LeConte Hall, Berkeley (United States)

2017-05-16

We derive a large class of codimension-two defects of 4d N=4 Super Yang-Mills (SYM) theory from the (2,0) little string. The origin of the little string is type IIB theory compactified on an ADE singularity. The defects are D-branes wrapping the 2-cycles of the singularity. We use this construction to make contact with the description of SYM defects due to Gukov and Witten https://arxiv.org/abs/hep-th/0612073. Furthermore, we provide a geometric perspective on the nilpotent orbit classification of codimension-two defects, and the connection to ADE-type Toda CFT. The only data needed to specify the defects is a set of weights of the algebra obeying certain constraints, which we give explicitly. We highlight the differences between the defect classification in the little string theory and its (2,0) CFT limit.

[Autologous chondrocyte implantation (ACI) for cartilage defects of the knee: a guideline by the working group "Tissue Regeneration" of the German Society of Orthopaedic Surgery and Traumatology (DGOU)].

Science.gov (United States)

Niemeyer, P; Andereya, S; Angele, P; Ateschrang, A; Aurich, M; Baumann, M; Behrens, P; Bosch, U; Erggelet, C; Fickert, S; Fritz, J; Gebhard, H; Gelse, K; Günther, D; Hoburg, A; Kasten, P; Kolombe, T; Madry, H; Marlovits, S; Meenen, N M; Müller, P E; Nöth, U; Petersen, J P; Pietschmann, M; Richter, W; Rolauffs, B; Rhunau, K; Schewe, B; Steinert, A; Steinwachs, M R; Welsch, G H; Zinser, W; Albrecht, D

2013-02-01

Autologous chondrocyte transplantation/implantation (ACT/ACI) is an established and recognised procedure for the treatment of localised full-thickness cartilage defects of the knee. The present review of the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Traumatology (DGOU) describes the biology and function of healthy articular cartilage, the present state of knowledge concerning potential consequences of primary cartilage lesions and the suitable indication for ACI. Based on current evidence, an indication for ACI is given for symptomatic cartilage defects starting from defect sizes of more than 3-4 cm2; in the case of young and active sports patients at 2.5 cm2. Advanced degenerative joint disease is the single most important contraindication. The review gives a concise overview on important scientific background, the results of clinical studies and discusses advantages and disadvantages of ACI. Georg Thieme Verlag KG Stuttgart · New York.

Reality check on girth weld defect acceptance criteria

Energy Technology Data Exchange (ETDEWEB)

Brust, Bud; Kalyanam, Suresh; Shim, Do-Jun; Wilkowski, Gery [Engineering Mechanics Corporation of Columbus, Columbus, OH, (United States)

2010-07-01

Girth weld defect tolerance criteria for pipeline construction has evolved with time. Recently, ERPG recommended a new Tier 2 girth weld defect acceptance criterion. This paper described the new development on girth weld defect acceptance criteria. The inherent conservatisms of alternative girth weld defect acceptance criteria from the 2007 API 1104 Appendix A, CSA Z662 Appendix K, are compared to those from the proposed EPRG Tier 2 criteria. It is found that the API and CSA codes have the same empirical limit-load criteria. As well, there are conservatisms in the proposed EPRG Tier 2. The results showed that there are various reasons why large amounts of conservatism in the allowable flaw lengths in the CSA Appendix K,2007 API 1104 Appendix A, and proposed EPRG Tier 2 girth weld defect criterion exist. Small conservatisms on failure stress can result in large conservatisms in flaw size.

Wound healing of osteotomy defects prepared with piezo or conventional surgical instruments: a pilot study in rabbits.

Science.gov (United States)

Ma, Li; Mattheos, Nikos; Sun, Yan; Liu, Xi Ling; Yip Chui, Ying; Lang, Niklaus Peter

2015-08-01

The aim of the present study was to evaluate and compare the wound-healing process following osteotomies performed with either conventional rotary burs or piezoelectric surgery in a rabbit model. Two types of osteotomy window defects of the nasal cavities were prepared on the nasal bone of 16 adult New Zealand white rabbits with either a conventional rotary bur or piezo surgery. The defects were covered with a resorbable membrane. Four animals were killed at 1, 2, 3, and 5 weeks after the surgical procedure, respectively. Histological and morphometric evaluations were performed to assess the volumetric density of various tissue components: the blood clot, vascularized structures, provisional matrix, osteoid, mineralized bone, bone debris, residual tissue, and old bone. Significantly more bone debris was found at 1 week in the conventionally-prepared defects compared to the piezo surgically-prepared defects. At 2 and 3 weeks, a newly-formed hard tissue bridge, mainly composed of woven bone, was seen; however, no statistically-significant differences were observed. At 5 weeks, the defects were completely filled with newly-formed bone. The defects prepared by piezo surgery showed a significantly decreased proportion of bone debris at 1 week, compared to conventional rotary bur defect. © 2014 Wiley Publishing Asia Pty Ltd.

Obturator with soft liner in the management of hard palate defect: A ...

African Journals Online (AJOL)

Maxillary defects are created following surgical treatment of patients with congenital defects, trauma, or neoplasm. Oral cancer is one of the more common malignanciesif detected lately massive tissues will be excised surgically and correction will be challenging. One of the treatment strategies is obturator, the retention of ...

Multilayer scaffolds in orthopaedic tissue engineering.

Science.gov (United States)

Atesok, Kivanc; Doral, M Nedim; Karlsson, Jon; Egol, Kenneth A; Jazrawi, Laith M; Coelho, Paulo G; Martinez, Amaury; Matsumoto, Tomoyuki; Owens, Brett D; Ochi, Mitsuo; Hurwitz, Shepard R; Atala, Anthony; Fu, Freddie H; Lu, Helen H; Rodeo, Scott A

2016-07-01

The purpose of this study was to summarize the recent developments in the field of tissue engineering as they relate to multilayer scaffold designs in musculoskeletal regeneration. Clinical and basic research studies that highlight the current knowledge and potential future applications of the multilayer scaffolds in orthopaedic tissue engineering were evaluated and the best evidence collected. Studies were divided into three main categories based on tissue types and interfaces for which multilayer scaffolds were used to regenerate: bone, osteochondral junction and tendon-to-bone interfaces. In vitro and in vivo studies indicate that the use of stratified scaffolds composed of multiple layers with distinct compositions for regeneration of distinct tissue types within the same scaffold and anatomic location is feasible. This emerging tissue engineering approach has potential applications in regeneration of bone defects, osteochondral lesions and tendon-to-bone interfaces with successful basic research findings that encourage clinical applications. Present data supporting the advantages of the use of multilayer scaffolds as an emerging strategy in musculoskeletal tissue engineering are promising, however, still limited. Positive impacts of the use of next generation scaffolds in orthopaedic tissue engineering can be expected in terms of decreasing the invasiveness of current grafting techniques used for reconstruction of bone and osteochondral defects, and tendon-to-bone interfaces in near future.

A large-scale study of the ultrawideband microwave dielectric properties of normal breast tissue obtained from reduction surgeries.

Science.gov (United States)

Lazebnik, Mariya; McCartney, Leah; Popovic, Dijana; Watkins, Cynthia B; Lindstrom, Mary J; Harter, Josephine; Sewall, Sarah; Magliocco, Anthony; Booske, John H; Okoniewski, Michal; Hagness, Susan C

2007-05-21

The efficacy of emerging microwave breast cancer detection and treatment techniques will depend, in part, on the dielectric properties of normal breast tissue. However, knowledge of these properties at microwave frequencies has been limited due to gaps and discrepancies in previously reported small-scale studies. To address these issues, we experimentally characterized the wideband microwave-frequency dielectric properties of a large number of normal breast tissue samples obtained from breast reduction surgeries at the University of Wisconsin and University of Calgary hospitals. The dielectric spectroscopy measurements were conducted from 0.5 to 20 GHz using a precision open-ended coaxial probe. The tissue composition within the probe's sensing region was quantified in terms of percentages of adipose, fibroconnective and glandular tissues. We fit a one-pole Cole-Cole model to the complex permittivity data set obtained for each sample and determined median Cole-Cole parameters for three groups of normal breast tissues, categorized by adipose tissue content (0-30%, 31-84% and 85-100%). Our analysis of the dielectric properties data for 354 tissue samples reveals that there is a large variation in the dielectric properties of normal breast tissue due to substantial tissue heterogeneity. We observed no statistically significant difference between the within-patient and between-patient variability in the dielectric properties.

A large-scale study of the ultrawideband microwave dielectric properties of normal breast tissue obtained from reduction surgeries

International Nuclear Information System (INIS)

Lazebnik, Mariya; McCartney, Leah; Popovic, Dijana; Watkins, Cynthia B; Lindstrom, Mary J; Harter, Josephine; Sewall, Sarah; Magliocco, Anthony; Booske, John H; Okoniewski, Michal; Hagness, Susan C

2007-01-01

The efficacy of emerging microwave breast cancer detection and treatment techniques will depend, in part, on the dielectric properties of normal breast tissue. However, knowledge of these properties at microwave frequencies has been limited due to gaps and discrepancies in previously reported small-scale studies. To address these issues, we experimentally characterized the wideband microwave-frequency dielectric properties of a large number of normal breast tissue samples obtained from breast reduction surgeries at University of Wisconsin and University of Calgary hospitals. The dielectric spectroscopy measurements were conducted from 0.5 to 20 GHz using a precision open-ended coaxial probe. The tissue composition within the probe's sensing region was quantified in terms of percentages of adipose, fibroconnective and glandular tissues. We fit a one-pole Cole-Cole model to the complex permittivity data set obtained for each sample and determined median Cole-Cole parameters for three groups of normal breast tissues, categorized by adipose tissue content (0-30%, 31-84% and 85-100%). Our analysis of the dielectric properties data for 354 tissue samples reveals that there is a large variation in the dielectric properties of normal breast tissue due to substantial tissue heterogeneity. We observed no statistically significant difference between the within-patient and between-patient variability in the dielectric properties

Trends in Tissue Engineering for Blood Vessels

Directory of Open Access Journals (Sweden)

Judee Grace Nemeno-Guanzon

2012-01-01

Full Text Available Over the years, cardiovascular diseases continue to increase and affect not only human health but also the economic stability worldwide. The advancement in tissue engineering is contributing a lot in dealing with this immediate need of alleviating human health. Blood vessel diseases are considered as major cardiovascular health problems. Although blood vessel transplantation is the most convenient treatment, it has been delimited due to scarcity of donors and the patient’s conditions. However, tissue-engineered blood vessels are promising alternatives as mode of treatment for blood vessel defects. The purpose of this paper is to show the importance of the advancement on biofabrication technology for treatment of soft tissue defects particularly for vascular tissues. This will also provide an overview and update on the current status of tissue reconstruction especially from autologous stem cells, scaffolds, and scaffold-free cellular transplantable constructs. The discussion of this paper will be focused on the historical view of cardiovascular tissue engineering and stem cell biology. The representative studies featured in this paper are limited within the last decade in order to trace the trend and evolution of techniques for blood vessel tissue engineering.

Repair of articular osteochondral defects of the knee joint using a composite lamellar scaffold.

Science.gov (United States)

Lv, Y M; Yu, Q S

2015-04-01

The major problem with repair of an articular cartilage injury is the extensive difference in the structure and function of regenerated, compared with normal cartilage. Our work investigates the feasibility of repairing articular osteochondral defects in the canine knee joint using a composite lamellar scaffold of nano-ß-tricalcium phosphate (ß-TCP)/collagen (col) I and II with bone marrow stromal stem cells (BMSCs) and assesses its biological compatibility. The bone-cartilage scaffold was prepared as a laminated composite, using hydroxyapatite nanoparticles (nano-HAP)/collagen I/copolymer of polylactic acid-hydroxyacetic acid as the bony scaffold, and sodium hyaluronate/poly(lactic-co-glycolic acid) as the cartilaginous scaffold. Ten-to 12-month-old hybrid canines were randomly divided into an experimental group and a control group. BMSCs were obtained from the iliac crest of each animal, and only those of the third generation were used in experiments. An articular osteochondral defect was created in the right knee of dogs in both groups. Those in the experimental group were treated by implanting the composites consisting of the lamellar scaffold of ß-TCP/col I/col II/BMSCs. Those in the control group were left untreated. After 12 weeks of implantation, defects in the experimental group were filled with white semi-translucent tissue, protruding slightly over the peripheral cartilage surface. After 24 weeks, the defect space in the experimental group was filled with new cartilage tissues, finely integrated into surrounding normal cartilage. The lamellar scaffold of ß-TCP/col I/col II was gradually degraded and absorbed, while new cartilage tissue formed. In the control group, the defects were not repaired. This method can be used as a suitable scaffold material for the tissue-engineered repair of articular cartilage defects. Cite this article: Bone Joint Res 2015;4:56-64. ©2015 The British Editorial Society of Bone & Joint Surgery.

An investigation of the flow dependence of temperature gradients near large vessels during steady state and transient tissue heating

International Nuclear Information System (INIS)

Kolios, M.C.; Worthington, A.E.; Hunt, J.W.; Holdsworth, D.W.; Sherar, M.D.

1999-01-01

Temperature distributions measured during thermal therapy are a major prognostic factor of the efficacy and success of the procedure. Thermal models are used to predict the temperature elevation of tissues during heating. Theoretical work has shown that blood flow through large blood vessels plays an important role in determining temperature profiles of heated tissues. In this paper, an experimental investigation of the effects of large vessels on the temperature distribution of heated tissue is performed. The blood flow dependence of steady state and transient temperature profiles created by a cylindrical conductive heat source and an ultrasound transducer were examined using a fixed porcine kidney as a flow model. In the transient experiments, a 20 s pulse of hot water, 30 deg. C above ambient, heated the tissues. Temperatures were measured at selected locations in steps of 0.1 mm. It was observed that vessels could either heat or cool tissues depending on the orientation of the vascular geometry with respect to the heat source and that these effects are a function of flow rate through the vessels. Temperature gradients of 6 deg. C mm -1 close to large vessels were routinely measured. Furthermore, it was observed that the temperature gradients caused by large vessels depended on whether the heating source was highly localized (i.e. a hot needle) or more distributed (i.e. external ultrasound). The gradients measured near large vessels during localized heating were between two and three times greater than the gradients measured during ultrasound heating at the same location, for comparable flows. Moreover, these gradients were more sensitive to flow variations for the localized needle heating. X-ray computed tomography data of the kidney vasculature were in good spatial agreement with the locations of all of the temperature variations measured. The three-dimensional vessel path observed could account for the complex features of the temperature profiles. The flow

Implications of defect clusters formed in cascades on free defect generation and microstructural development

International Nuclear Information System (INIS)

Wiedersich, H.

1992-12-01

A large fraction of the defects produced by irradiation with energetic neutrons or heavy ions originates in cascades. Not only increased recombination of vacancy and interstitial defects but also significant clustering of like defects occur. Both processes reduce the number of point defects available for long range migration. Consequences of defect clustering in cascades will be discussed in a semi-quantitative form with the aid of calculations using a very simplified model: Quasi-steady-state distributions of immobile vacancy and/or interstitial clusters develop which, in turn, can become significant sinks for mobile defects, and, therefore reduce their lifetime. Although cluster sinks will cause segregation and, potentially, precipitation of second phases due to local changes of composition, the finite lifetime of clusters will not lead to lasting, local compositional changes. A transition from highly dense interstitial and vacancy cluster distributions to the void swelling regime occurs when the thermal evaporation of vacancies from small vacancy clusters becomes significant at higher temperatures. Unequal clustering of vacancies and interstitials leads to an imbalance of their fluxes of in the matrix and, hence, to unequal contributions to atom transport by interstitials and by vacancies even in the quasi-steady state approximation

Hard tissue compatibility of natural hydroxyapatite/chitosan composite

International Nuclear Information System (INIS)

Tang Xiaojun; Gui Lai; Lue Xiaoying

2008-01-01

The natural hydroxyapatite/chitosan (NHC) composite is a new synthesized material. The aim of this experiment was to assess the bone tissue compatibility of this NHC composite in vivo. Twenty-four healthy New Zealand rabbits were included in this study. Of those, 20 were used as the experimental group and four as the control group. In the experimental group, animals receive a cranium defect procedure and NHC composite repair. In the control group, animals underwent the cranium defect procedure without NHC composite repair. At 1, 4, 12, 24, and 40 weeks after surgery, the animals were sacrificed and samples were taken and assessed by gross observation, three-dimensional (3D) computerized tomographic (CT) reconstruction, histology and scanning electron microscope. Our results showed that at 1 week after repairing the bone defect with the NHC composite in the experimental group, new bone appeared around the composite and matured gradually. At 24 weeks after surgery, there were little collagenous tissues present between the material and surrounding bones. At 40 weeks after surgery, new bone had grown into the mature bone and total osseointegration had occurred. In the control group, however, no bone defect healing was observed at 40 weeks after surgery. All these results of the present in vivo work suggest that the NHC composite has a good hard tissue biocompatibility and an excellent osteoconductivity. It is suitable for artificial bone implants and frame materials of tissue engineering.

Hard tissue compatibility of natural hydroxyapatite/chitosan composite

Energy Technology Data Exchange (ETDEWEB)

Tang Xiaojun; Gui Lai [Department of Cranio-maxillofacial Surgery, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 33 Ba-Da-Chu Road, Beijing, 100144 (China); Lue Xiaoying [State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096 (China)], E-mail: laiguiplastic@tom.com, E-mail: luxy@seu.edu.cn

2008-12-15

The natural hydroxyapatite/chitosan (NHC) composite is a new synthesized material. The aim of this experiment was to assess the bone tissue compatibility of this NHC composite in vivo. Twenty-four healthy New Zealand rabbits were included in this study. Of those, 20 were used as the experimental group and four as the control group. In the experimental group, animals receive a cranium defect procedure and NHC composite repair. In the control group, animals underwent the cranium defect procedure without NHC composite repair. At 1, 4, 12, 24, and 40 weeks after surgery, the animals were sacrificed and samples were taken and assessed by gross observation, three-dimensional (3D) computerized tomographic (CT) reconstruction, histology and scanning electron microscope. Our results showed that at 1 week after repairing the bone defect with the NHC composite in the experimental group, new bone appeared around the composite and matured gradually. At 24 weeks after surgery, there were little collagenous tissues present between the material and surrounding bones. At 40 weeks after surgery, new bone had grown into the mature bone and total osseointegration had occurred. In the control group, however, no bone defect healing was observed at 40 weeks after surgery. All these results of the present in vivo work suggest that the NHC composite has a good hard tissue biocompatibility and an excellent osteoconductivity. It is suitable for artificial bone implants and frame materials of tissue engineering.

Temporalis myofascial repair of traumatic defects of the anterior fossa. Technical note.

Science.gov (United States)

Gillespie, R P; Shagets, F W; de los Reyes, R A

1986-06-01

Bilateral temporalis myofascial flaps in continuity with frontal periosteum can be used in repairing extensive dural and bone defects of the anterior cranial fossa floor. The technique of preserving and using this flap is described and offers an alternative to the use of frontal pericranial tissue for repair of anterior dural defects.

Alveolar ridge augmentation by connective tissue grafting using a pouch method and modified connective tissue technique: A prospective study

Directory of Open Access Journals (Sweden)

Ashish Agarwal

2015-01-01

Full Text Available Background: Localized alveolar ridge defect may create physiological and pathological problems. Developments in surgical techniques have made it simpler to change the configuration of a ridge to create a more aesthetic and more easily cleansable shape. The purpose of this study was to compare the efficacy of alveolar ridge augmentation using a subepithelial connective tissue graft in pouch and modified connective tissue graft technique. Materials and Methods: In this randomized, double blind, parallel and prospective study, 40 non-smoker individuals with 40 class III alveolar ridge defects in maxillary anterior were randomly divided in two groups. Group I received modified connective tissue graft, while group II were treated with subepithelial connective tissue graft in pouch technique. The defect size was measured in its horizontal and vertical dimension by utilizing a periodontal probe in a stone cast at base line, after 3 months, and 6 months post surgically. Analysis of variance and Bonferroni post-hoc test were used for statistical analysis. A two-tailed P < 0.05 was considered to be statistically significant. Results: Mean values in horizontal width after 6 months were 4.70 ± 0.87 mm, and 4.05 ± 0.89 mm for group I and II, respectively. Regarding vertical heights, obtained mean values were 4.75 ± 0.97 mm and 3.70 ± 0.92 mm for group I and group II, respectively. Conclusion: Within the limitations of this study, connective tissue graft proposed significantly more improvement as compare to connective tissue graft in pouch.

The cardiac proteome in patients with congenital ventricular septal defect: A comparative study between right atria and right ventricles.

Science.gov (United States)

Bond, A R; Iacobazzi, D; Abdul-Ghani, S; Ghorbel, M T; Heesom, K J; George, S J; Caputo, M; Suleiman, M-S; Tulloh, R M

2018-03-20

Right ventricle (RV) remodelling occurs in neonatal patients born with ventricular septal defect (VSD). The presence of a defect between the two ventricles allows for shunting of blood from the left to right side. The resulting RV hypertrophy leads to molecular remodelling which has thus far been largely investigated using right atrial (RA) tissue. In this study we used proteomic and phosphoproteomic analysis in order to determine any difference between the proteomes for RA and RV. Samples were therefore taken from the RA and RV of five infants (0.34 ± 0.05 years, mean ± SEM) with VSD who were undergoing cardiac surgery to repair the defect. Significant differences in protein expression between RV and RA were seen. 150 protein accession numbers were identified which were significantly lower in the atria, whereas none were significantly higher in the atria compared to the ventricle. 19 phosphorylation sites (representing 19 phosphoproteins) were also lower in RA. This work has identified differences in the proteome between RA and RV which reflect differences in contractile activity and metabolism. As such, caution should be used when drawing conclusions based on analysis of the RA and extrapolating to the hypertrophied RV. RV hypertrophy occurs in neonatal patients born with VSD. Very little is known about how the atria responds to RV hypertrophy, especially at the protein level. Access to tissue from age-matched groups of patients is very rare, and we are in the unique position of being able to get tissue from both the atria and ventricle during reparative surgery of these infants. Our findings will be beneficial to future research into heart chamber malformations in congenital heart defects. Copyright © 2018. Published by Elsevier B.V.

Influence of the gel thickness on in vivo hyaline cartilage regeneration induced by double-network gel implanted at the bottom of a large osteochondral defect: Short-term results

Directory of Open Access Journals (Sweden)

Matsuda Hidetoshi

2013-01-01

Full Text Available Abstract Background A double-network (DN gel, which is composed of poly(2-acrylamido-2-methylpropanesulfonic acid and poly(N,N’-dimethyl acrylamide, can induce hyaline cartilage regeneration in vivo in a large osteochondral defect. The purpose of this study was to clarify the influence of the thickness of the implanted DN gel on the induction ability of hyaline cartilage regeneration. Methods Thirty-eight mature rabbits were used in this study. We created an osteochondral defect having a diameter of 4.3-mm in the patellofemoral joint. The knees were randomly divided into 4 groups (Group I: 0.5-mm thick gel, Group II: 1.0-mm thick gel, Group III: 5.0-mm thick gel, and Group IV: untreated control. Animals in each group were further divided into 3 sub-groups depending on the gel implant position (2.0-, 3.0-, or 4.0-mm depth from the articular surface in the defect. The regenerated tissues were evaluated with the Wayne’s gross and histological grading scales and real time PCR analysis of the cartilage marker genes at 4 weeks. Results According to the total Wayne’s score, when the depth of the final vacant space was set at 2.0 mm, the scores in Groups I, II, and III were significantly greater than that Group IV (p  Conclusions The 1.0-mm thick DN gel sheet had the same ability to induce hyaline cartilage regeneration as the 5.0-mm thick DN gel plug. However, the induction ability of the 0.5-mm thick sheet was significantly lower when compared with the 1.0-mm thick gel sheet. The 1.0-mm DN gel sheet is a promising device to establish a cell-free cartilage regeneration strategy that minimizes bone loss from the gel implantation.

Characterization and evaluation of graphene oxide scaffold for periodontal wound healing of class II furcation defects in dog.

Science.gov (United States)

Kawamoto, Kohei; Miyaji, Hirofumi; Nishida, Erika; Miyata, Saori; Kato, Akihito; Tateyama, Akito; Furihata, Tomokazu; Shitomi, Kanako; Iwanaga, Toshihiko; Sugaya, Tsutomu

2018-01-01

The 3-dimensional scaffold plays a key role in volume and quality of repair tissue in periodontal tissue engineering therapy. We fabricated a novel 3D collagen scaffold containing carbon-based 2-dimensional layered material, named graphene oxide (GO). The aim of this study was to characterize and assess GO scaffold for periodontal tissue healing of class II furcation defects in dog. GO scaffolds were prepared by coating the surface of a 3D collagen sponge scaffold with GO dispersion. Scaffolds were characterized using cytotoxicity and tissue reactivity tests. In addition, GO scaffold was implanted into dog class II furcation defects and periodontal healing was investigated at 4 weeks postsurgery. GO scaffold exhibited low cytotoxicity and enhanced cellular ingrowth behavior and rat bone forming ability. In addition, GO scaffold stimulated healing of dog class II furcation defects. Periodontal attachment formation, including alveolar bone, periodontal ligament-like tissue, and cementum-like tissue, was significantly increased by GO scaffold implantation, compared with untreated scaffold. The results suggest that GO scaffold is biocompatible and possesses excellent bone and periodontal tissue formation ability. Therefore, GO scaffold would be beneficial for periodontal tissue engineering therapy.

Bimaxillary protrusion with an atrophic alveolar defect: orthodontics, autogenous chin-block graft, soft tissue augmentation, and an implant.

Science.gov (United States)

Chiu, Grace S C; Chang, Chris H N; Roberts, W Eugene

2015-01-01

Bimaxillary protrusion in a 28-year-old woman was complicated by multiple missing, restoratively compromised, or hopeless teeth. The maxillary right central incisor had a history of avulsion and replantation that subsequently evolved into generalized external root resorption with Class III mobility and severe loss of the supporting periodontium. This complex malocclusion had a discrepancy index of 21, and 8 additional points were scored for the atrophic dental implant site (maxillary right central incisor). The comprehensive treatment plan included extraction of 4 teeth (both maxillary first premolars, the maxillary right central incisor, and the mandibular right first molar), orthodontic closure of all spaces except for the future implant site (maxillary right central incisor), augmentation of the alveolar defect with an autogenous chin-block graft, enhancement of the gingival biotype with a connective tissue graft, and an implant-supported prosthesis. Orthodontists must understand the limitations of bone grafts. Augmented alveolar defects are slow to completely turn over to living bone, so they are usually good sites for implants but respond poorly to orthodontic space closure. However, postsurgical orthodontic treatment is often indicated to optimally finish the esthetic zone before placing the final prosthesis. The latter was effectively performed for this patient, resulting in a total treatment time of about 36 months for comprehensive interdisciplinary care. An excellent functional and esthetic result was achieved. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Primordial inhomogeneities from massive defects during inflation

Energy Technology Data Exchange (ETDEWEB)

Firouzjahi, Hassan; Karami, Asieh; Rostami, Tahereh, E-mail: firouz@ipm.ir, E-mail: karami@ipm.ir, E-mail: t.rostami@ipm.ir [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

2016-10-01

We consider the imprints of local massive defects, such as a black hole or a massive monopole, during inflation. The massive defect breaks the background homogeneity. We consider the limit that the physical Schwarzschild radius of the defect is much smaller than the inflationary Hubble radius so a perturbative analysis is allowed. The inhomogeneities induced in scalar and gravitational wave power spectrum are calculated. We obtain the amplitudes of dipole, quadrupole and octupole anisotropies in curvature perturbation power spectrum and identify the relative configuration of the defect to CMB sphere in which large observable dipole asymmetry can be generated. We observe a curious reflection symmetry in which the configuration where the defect is inside the CMB comoving sphere has the same inhomogeneous variance as its mirror configuration where the defect is outside the CMB sphere.

Percutaneous endoscopic intra-annular subligamentous herniotomy for large central disc herniation: a technical case report.

Science.gov (United States)

Lee, Sang-Ho; Choi, Kyung-Chul; Baek, Oon Ki; Kim, Ho Jin; Yoo, Seung-Hwa

2014-04-01

Technical case report. To describe the novel technique of percutaneous endoscopic herniotomy using a unilateral intra-annular subligamentous approach for the treatment of large centrally herniated discs. Open discectomy for large central disc herniations may have poor long-term prognosis due to heavy loss of intervertebral disc tissue, segmental instability, and recurrence of pain. Six consecutive patients who presented with back and leg pain, and/or weakness due to a large central disc herniation were treated using percutaneous endoscopic herniotomy with a unilateral intra-annular subligamentous approach. The patients experienced relief of symptoms and intervertebral disc spaces were well maintained. The annular defects were noted to be in the process of healing and recovery. Percutaneous endoscopic unilateral intra-annular subligamentous herniotomy was an effective and affordable minimally invasive procedure for patients with large central disc herniations, allowing preservation of nonpathological intradiscal tissue through a concentric outer-layer annular approach.

Face resurfacing using a cervicothoracic skin flap prefabricated by lateral thigh fascial flap and tissue expander.

Science.gov (United States)

Li, Qingfeng; Zan, Tao; Gu, Bin; Liu, Kai; Shen, Guoxiong; Xie, Yun; Weng, Rui

2009-01-01

Resurfacing of facial massive soft tissue defect is a formidable challenge because of the unique character of the region and the limitation of well-matched donor site. In this report, we introduce a technique for using the prefabricated cervicothoracic skin flap for facial resurfacing, in an attempt to meet the principle of flap selection in face reconstructive surgery for matching the color and texture, large dimension, and thinner thickness (MLT) of the recipient. Eleven patients with massive facial scars underwent resurfacing procedures with prefabricated cervicothoracic flaps. The vasculature of the lateral thigh fascial flap, including the descending branch of the lateral femoral circumflex vessels and the surrounding muscle fascia, was used as the vascular carrier, and the pedicles of the fascial flap were anastomosed to either the superior thyroid or facial vessels in flap prefabrication. A tissue expander was placed beneath the fascial flap to enlarge the size and reduce the thickness of the flap. The average size of the harvested fascia flap was 6.5 x 11.7 cm. After a mean interval of 21.5 weeks, the expanders were filled to a mean volume of 1,685 ml. The sizes of the prefabricated skin flaps ranged from 12 x 15 cm to 15 x 32 cm. The prefabricated skin flaps were then transferred to the recipient site as pedicled flaps for facial resurfacing. All facial soft tissue defects were successfully covered by the flaps. The donor sites were primarily closed and healed without complications. Although varied degrees of venous congestion were developed after flap transfers, the marginal necrosis only occurred in two cases. The results in follow-up showed most resurfaced faces restored natural contour and regained emotional expression. MLT is the principle for flap selection in resurfacing of the massive facial soft tissue defect. Our experience in this series of patients demonstrated that the prefabricated cervicothoracic skin flap could be a reliable alternative

Treatment of a Focal Articular Cartilage Defect of the Talus with Polymer-Based Autologous Chondrocyte Implantation: A 12-Year Follow-Up Period.

Science.gov (United States)

Kreuz, Peter Cornelius; Kalkreuth, Richard Horst; Niemeyer, Philipp; Uhl, Markus; Erggelet, Christoph

Autologous chondrocyte implantation (ACI) is a first-line treatment option for large articular cartilage defects. Although well-established for cartilage defects in the knee, studies of the long-term outcomes of matrix-assisted ACI to treat cartilage defects in the ankle are rare. In the present report, we describe for the first time the long-term clinical and radiologic results 12 years after polymer-based matrix-assisted ACI treat a full-thickness talar cartilage defect in a 25-year-old male patient. The clinical outcome was assessed using the visual analog scale and Freiburg ankle score, magnetic resonance imaging evaluation using the Henderson-Kreuz scoring system and T2 mapping. Clinical assessment revealed improved visual analog scale and Freiburg ankle scores. The radiologic analysis and T2 relaxation time values indicated the formation of hyaline-like repair tissue. Polymer-based autologous chondrocytes has been shown to be a safe and clinically effective long-term treatment of articular cartilage defects in the talus. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Multiscale crystal defect dynamics: A coarse-grained lattice defect model based on crystal microstructure

Science.gov (United States)

Lyu, Dandan; Li, Shaofan

2017-10-01

Crystal defects have microstructure, and this microstructure should be related to the microstructure of the original crystal. Hence each type of crystals may have similar defects due to the same failure mechanism originated from the same microstructure, if they are under the same loading conditions. In this work, we propose a multiscale crystal defect dynamics (MCDD) model that models defects by considering its intrinsic microstructure derived from the microstructure or material genome of the original perfect crystal. The main novelties of present work are: (1) the discrete exterior calculus and algebraic topology theory are used to construct a scale-up (coarse-grained) dual lattice model for crystal defects, which may represent all possible defect modes inside a crystal; (2) a higher order Cauchy-Born rule (up to the fourth order) is adopted to construct atomistic-informed constitutive relations for various defect process zones, and (3) an hierarchical strain gradient theory based finite element formulation is developed to support an hierarchical multiscale cohesive (process) zone model for various defects in a unified formulation. The efficiency of MCDD computational algorithm allows us to simulate dynamic defect evolution at large scale while taking into account atomistic interaction. The MCDD model has been validated by comparing of the results of MCDD simulations with that of molecular dynamics (MD) in the cases of nanoindentation and uniaxial tension. Numerical simulations have shown that MCDD model can predict dislocation nucleation induced instability and inelastic deformation, and thus it may provide an alternative solution to study crystal plasticity.

Failures and Defects in the Building Process

DEFF Research Database (Denmark)

Jørgensen, Kirsten

2009-01-01

Function failures, defects, mistakes and poor communication are major problems for the construction sector. As the empirical element in the research, a large construction site was observed from the very start to the very end and all failures and defects of a certain size were recorded and analysed...

Multilayer porous UHMWPE scaffolds for bone defects replacement

International Nuclear Information System (INIS)

Maksimkin, A.V.; Senatov, F.S.; Anisimova, N.Yu.; Kiselevskiy, M.V.; Zalepugin, D.Yu.; Chernyshova, I.V.; Tilkunova, N.A.; Kaloshkin, S.D.

2017-01-01

Reconstruction of the structural integrity of the damaged bone tissue is an urgent problem. UHMWPE may be potentially used for the manufacture of porous implants simulating as closely as possible the porous cancellous bone tissue. But the extremely high molecular weight of the polymer does not allow using traditional methods of foaming. Porous and multilayer UHMWPE scaffolds with nonporous bulk layer and porous layer that mimics cancellous bone architecture were obtained by solid-state mixing, thermopressing and washing in subcritical water. Structural and mechanical properties of the samples were studied. Porous UHMWPE samples were also studied in vitro and in vivo. The pores of UHMWPE scaffold are open and interconnected. Volume porosity of the obtained samples was 79 ± 2%; the pore size range was 80–700 μm. Strong connection of the two layers in multilayer UHMWPE scaffolds was observed with decreased number of fusion defects. Functionality of implants based on multilayer UHMWPE scaffolds is provided by the fixation of scaffolds in the bone defect through ingrowths of the connective tissue into the pores, which ensures the maintenance of the animals' mobility - Highlights: • Porous UHMWPE scaffold mimics cancellous bone architecture, maintaining its flexibility. • Multilayer UHMWPE scaffold is able to simulate different types of bone tissue. • Fixation of scaffolds in the bone provides through ingrowths of the connective tissue into pores. • Multilayer UHMWPE scaffolds can be used for the formation of bone implants.

Multilayer porous UHMWPE scaffolds for bone defects replacement

Energy Technology Data Exchange (ETDEWEB)

Maksimkin, A.V. [National University of Science and Technology “MISIS”, Moscow (Russian Federation); Senatov, F.S., E-mail: senatov@misis.ru [National University of Science and Technology “MISIS”, Moscow (Russian Federation); Anisimova, N.Yu.; Kiselevskiy, M.V. [National University of Science and Technology “MISIS”, Moscow (Russian Federation); N.N. Blokhin Russian Cancer Research Center, Moscow (Russian Federation); Zalepugin, D.Yu.; Chernyshova, I.V.; Tilkunova, N.A. [State Plant of Medicinal Drugs, Moscow (Russian Federation); Kaloshkin, S.D. [National University of Science and Technology “MISIS”, Moscow (Russian Federation)

2017-04-01

Reconstruction of the structural integrity of the damaged bone tissue is an urgent problem. UHMWPE may be potentially used for the manufacture of porous implants simulating as closely as possible the porous cancellous bone tissue. But the extremely high molecular weight of the polymer does not allow using traditional methods of foaming. Porous and multilayer UHMWPE scaffolds with nonporous bulk layer and porous layer that mimics cancellous bone architecture were obtained by solid-state mixing, thermopressing and washing in subcritical water. Structural and mechanical properties of the samples were studied. Porous UHMWPE samples were also studied in vitro and in vivo. The pores of UHMWPE scaffold are open and interconnected. Volume porosity of the obtained samples was 79 ± 2%; the pore size range was 80–700 μm. Strong connection of the two layers in multilayer UHMWPE scaffolds was observed with decreased number of fusion defects. Functionality of implants based on multilayer UHMWPE scaffolds is provided by the fixation of scaffolds in the bone defect through ingrowths of the connective tissue into the pores, which ensures the maintenance of the animals' mobility - Highlights: • Porous UHMWPE scaffold mimics cancellous bone architecture, maintaining its flexibility. • Multilayer UHMWPE scaffold is able to simulate different types of bone tissue. • Fixation of scaffolds in the bone provides through ingrowths of the connective tissue into pores. • Multilayer UHMWPE scaffolds can be used for the formation of bone implants.

Bioactive glass-based scaffolds for bone tissue engineering

NARCIS (Netherlands)

Will, J.; Gerhardt, L.C.; Boccaccini, A.R.

2012-01-01

Originally developed to fill and restore bone defects, bioactive glasses are currently also being intensively investigated for bone tissue engineering applications. In this chapter, we review and discuss current knowledge on porous bone tissue engineering scaffolds made from bioactive silicate

Deletion of Nhlh2 results in a defective torpor response and reduced Beta adrenergic receptor expression in adipose tissue.

Directory of Open Access Journals (Sweden)

Umesh D Wankhade

2010-08-01

Full Text Available Mice with a targeted deletion of the basic helix-loop-helix transcription factor, Nescient Helix-Loop-Helix 2 (Nhlh2, display adult-onset obesity with significant increases in their fat depots, abnormal responses to cold exposure, and reduced spontaneous physical activity levels. These phenotypes, accompanied by the hypothalamic expression of Nhlh2, make the Nhlh2 knockout (N2KO mouse a useful model to study the role of central nervous system (CNS control on peripheral tissue such as adipose tissue.Differences in body temperature and serum analysis of leptin were performed in fasted and ad lib fed wild-type (WT and N2KO mice. Histological analysis of white (WAT and brown adipose tissue (BAT was performed. Gene and protein level expression of inflammatory and metabolic markers were compared between the two genotypes.We report significant differences in serum leptin levels and body temperature in N2KO mice compared with WT mice exposed to a 24-hour fast, suggestive of a defect in both white (WAT and brown adipose tissue (BAT function. As compared to WT mice, N2KO mice showed increased serum IL-6 protein and WAT IL-6 mRNA levels. This was accompanied by slight elevations of mRNA for several macrophage markers, including expression of macrophage specific protein F4/80 in adipose, suggestive of macrophage infiltration of WAT in the mutant animals. The mRNAs for beta3-adrenergic receptors (beta3-AR, beta2-AR and uncoupling proteins were significantly reduced in WAT and BAT from N2KO mice compared with WT mice.These studies implicate Nhlh2 in the central control of WAT and BAT function, with lack of Nhlh2 leading to adipose inflammation and altered gene expression, impaired leptin response to fasting, all suggestive of a deficient torpor response in mutant animals.

Tissue-Specific Methylation of Long Interspersed Nucleotide Element-1 of Homo Sapiens (L1Hs) During Human Embryogenesis and Roles in Neural Tube Defects.

Science.gov (United States)

Wang, L; Chang, S; Guan, J; Shangguan, S; Lu, X; Wang, Z; Wu, L; Zou, J; Zhao, H; Bao, Y; Qiu, Z; Niu, B; Zhang, T

2015-01-01

Epigenetic regulation of long interspersed nucleotide element-1 (LINE-1) retrotransposition events plays crucial roles during early development. Previously we showed that LINE-1 hypomethylation in neuronal tissues is associated with pathogenesis of neural tube defect (NTD). Herein, we further evaluated LINE-1 Homo sapiens (L1Hs) methylation in tissues derived from three germ layers of stillborn NTD fetuses, to define patterns of tissue specific methylation and site-specific hypomethylation at CpG sites within an L1Hs promoter region. Stable, tissue-specific L1Hs methylation patterns throughout three germ layer lineages of the fetus, placenta, and maternal peripheral blood were observed. Samples from maternal peripheral blood exhibited the highest level of L1Hs methylation (64.95%) and that from placenta showed the lowest (26.82%). Between samples from NTDs and controls, decrease in L1Hs methylation was only significant in NTD-affected brain tissue at 7.35%, especially in females (8.98%). L1Hs hypomethylation in NTDs was also associated with a significant increase in expression level of an L1Hs-encoded transcript in females (r = -0.846, p = 0.004). This could be due to genomic DNA instability and alternation in chromatins accessibility resulted from abnormal L1Hs hypomethylation, as showed in this study with HCT-15 cells treated with methylation inhibitor 5-Aza.

Multilayer porous UHMWPE scaffolds for bone defects replacement.

Science.gov (United States)

Maksimkin, A V; Senatov, F S; Anisimova, N Yu; Kiselevskiy, M V; Zalepugin, D Yu; Chernyshova, I V; Tilkunova, N A; Kaloshkin, S D

2017-04-01

Reconstruction of the structural integrity of the damaged bone tissue is an urgent problem. UHMWPE may be potentially used for the manufacture of porous implants simulating as closely as possible the porous cancellous bone tissue. But the extremely high molecular weight of the polymer does not allow using traditional methods of foaming. Porous and multilayer UHMWPE scaffolds with nonporous bulk layer and porous layer that mimics cancellous bone architecture were obtained by solid-state mixing, thermopressing and washing in subcritical water. Structural and mechanical properties of the samples were studied. Porous UHMWPE samples were also studied in vitro and in vivo. The pores of UHMWPE scaffold are open and interconnected. Volume porosity of the obtained samples was 79±2%; the pore size range was 80-700μm. Strong connection of the two layers in multilayer UHMWPE scaffolds was observed with decreased number of fusion defects. Functionality of implants based on multilayer UHMWPE scaffolds is provided by the fixation of scaffolds in the bone defect through ingrowths of the connective tissue into the pores, which ensures the maintenance of the animals' mobility. Copyright © 2016 Elsevier B.V. All rights reserved.

Repair of articular cartilage defects in the knee with autologous iliac crest cartilage in a rabbit model.

Science.gov (United States)

Jing, Lizhong; Zhang, Jiying; Leng, Huijie; Guo, Qinwei; Hu, Yuelin

2015-04-01

To demonstrate that iliac crest cartilage may be used to repair articular cartilage defects in the knees of rabbits. Full-thickness cartilage defects were created in the medial femoral condyle on both knees of 36 New Zealand white rabbits. The 72 defects were randomly assigned to be repaired with ipsilateral iliac crest cartilage (Group I), osteochondral tissues removed at defect creation (Group II), or no treatment (negative control, Group III). Animals were killed at 6, 12, and 24 weeks post-operatively. The repaired tissues were harvested for magnetic resonance imaging (MRI), histological studies (haematoxylin and eosin and immunohistochemical staining), and mechanical testing. At 6 weeks, the iliac crest cartilage graft was not yet well integrated with the surrounding articular cartilage, but at 12 weeks, the graft deep zone had partial ossification. By 24 weeks, the hyaline cartilage-like tissue was completely integrated with the surrounding articular cartilage. Osteochondral autografts showed more rapid healing than Group I at 6 weeks and complete healing at 12 weeks. Untreated defects were concave or partly filled with fibrous tissue throughout the study. MRI showed that Group I had slower integration with surrounding normal cartilage compared with Group II. The mechanical properties of Group I were significantly lower than those of Group II at 12 weeks, but this difference was not significant at 24 weeks. Iliac crest cartilage autografts were able to repair knee cartilage defects with hyaline cartilage and showed comparable results with osteochondral autografts in the rabbit model.

Patch esophagoplasty using an in-body-tissue-engineered collagenous connective tissue membrane.

Science.gov (United States)

Okuyama, Hiroomi; Umeda, Satoshi; Takama, Yuichi; Terasawa, Takeshi; Nakayama, Yasuhide

2018-02-01

Although many approaches to esophageal replacement have been investigated, these efforts have thus far only met limited success. In-body-tissue-engineered connective tissue tubes have been reported to be effective as vascular replacement grafts. The aim of this study was to investigate the usefulness of an In-body-tissue-engineered collagenous connective tissue membrane, "Biosheet", as a novel esophageal scaffold in a beagle model. We prepared Biosheets by embedding specially designed molds into subcutaneous pouches in beagles. After 1-2months, the molds, which were filled with ingrown connective tissues, were harvested. Rectangular-shaped Biosheets (10×20mm) were then implanted to replace defects of the same size that had been created in the cervical esophagus of the beagle. An endoscopic evaluation was performed at 4 and 12weeks after implantation. The esophagus was harvested and subjected to a histological evaluation at 4 (n=2) and 12weeks (n=2) after implantation. The animal study protocols were approved by the National Cerebral and Cardiovascular Centre Research Institute Committee (No. 16048). The Biosheets showed sufficient strength and flexibility to replace the esophagus defect. All animals survived with full oral feeding during the study period. No anastomotic leakage was observed. An endoscopic study at 4 and 12weeks after implantation revealed that the anastomotic sites and the internal surface of the Biosheets were smooth, without stenosis. A histological analysis at 4weeks after implantation demonstrated that stratified squamous epithelium was regenerated on the internal surface of the Biosheets. A histological analysis at 12weeks after implantation showed the regeneration of muscle tissue in the implanted Biosheets. The long-term results of patch esophagoplasty using Biosheets showed regeneration of stratified squamous epithelium and muscular tissues in the implanted sheets. These results suggest that Biosheets may be useful as a novel esophageal

Exploring atomic defects in molybdenum disulphide monolayers

KAUST Repository

Hong, Jinhua; Hu, Zhixin; Probert, Matt; Li, Kun; Lv, Danhui; Yang, Xinan; Gu, Lin; Mao, Nannan; Feng, Qingliang; Xie, Liming; Zhang, Jin; Wu, Dianzhong; Zhang, Zhiyong; Jin, Chuanhong; Ji, Wei; Zhang, Xixiang; Yuan, Jun; Zhang, Ze

2015-01-01

Defects usually play an important role in tailoring various properties of two-dimensional materials. Defects in two-dimensional monolayer molybdenum disulphide may be responsible for large variation of electric and optical properties. Here we present a comprehensive joint experiment-theory investigation of point defects in monolayer molybdenum disulphide prepared by mechanical exfoliation, physical and chemical vapour deposition. Defect species are systematically identified and their concentrations determined by aberration-corrected scanning transmission electron microscopy, and also studied by ab-initio calculation. Defect density up to 3.5 × 10 13 cm '2 is found and the dominant category of defects changes from sulphur vacancy in mechanical exfoliation and chemical vapour deposition samples to molybdenum antisite in physical vapour deposition samples. Influence of defects on electronic structure and charge-carrier mobility are predicted by calculation and observed by electric transport measurement. In light of these results, the growth of ultra-high-quality monolayer molybdenum disulphide appears a primary task for the community pursuing high-performance electronic devices.

Exploring atomic defects in molybdenum disulphide monolayers

KAUST Repository

Hong, Jinhua

2015-02-19

Defects usually play an important role in tailoring various properties of two-dimensional materials. Defects in two-dimensional monolayer molybdenum disulphide may be responsible for large variation of electric and optical properties. Here we present a comprehensive joint experiment-theory investigation of point defects in monolayer molybdenum disulphide prepared by mechanical exfoliation, physical and chemical vapour deposition. Defect species are systematically identified and their concentrations determined by aberration-corrected scanning transmission electron microscopy, and also studied by ab-initio calculation. Defect density up to 3.5 × 10 13 cm \\'2 is found and the dominant category of defects changes from sulphur vacancy in mechanical exfoliation and chemical vapour deposition samples to molybdenum antisite in physical vapour deposition samples. Influence of defects on electronic structure and charge-carrier mobility are predicted by calculation and observed by electric transport measurement. In light of these results, the growth of ultra-high-quality monolayer molybdenum disulphide appears a primary task for the community pursuing high-performance electronic devices.

Quality of Newly Formed Cartilaginous Tissue in Defects of Articular Surface after Transplantation of Mesenchymal Stem Cells in a Composite Scaffold Based on Collagen I with Chitosan Micro- and Nanofibres

Czech Academy of Sciences Publication Activity Database

Nečas, A.; Plánka, L.; Srnec, R.; Crha, M.; Hlučilová, Jana; Klíma, Jiří; Starý, L.; Křen, L.; Amler, Evžen; Vojtová, L.; Jančář, J.; Gál, P.

2010-01-01

Roč. 59, č. 4 (2010), s. 605-614 ISSN 0862-8408 R&D Projects: GA MŠk 2B06130 Institutional research plan: CEZ:AV0Z50450515; CEZ:AV0Z50390512 Keywords : Cartilaginous Tissue * Defects of Articular Surface * Mesenchymal Stem Cells Subject RIV: CE - Biochemistry Impact factor: 1.646, year: 2010

First-Principles Investigations of Defects in Minerals

Science.gov (United States)

Verma, Ashok K.

2011-07-01

The ideal crystal has an infinite 3-dimensional repetition of identical units which may be atoms or molecules. But real crystals are limited in size and they have disorder in stacking which as called defects. Basically three types of defects exist in solids: 1) point defects, 2) line defects, and 3) surface defects. Common point defects are vacant lattice sites, interstitial atoms and impurities and these are known to influence strongly many solid-state transport properties such as diffusion, electrical conduction, creep, etc. In thermal equilibrium point defects concentrations are determined by their formation enthalpies and their movement by their migration barriers. Line and surface defects are though absent from the ideal crystal in thermal equilibrium due to higher energy costs but they are invariably present in all real crystals. Line defects include edge-, screw- and mixed-dislocations and their presence is essential in explaining the mechanical strength and deformation of real crystals. Surface defects may arise at the boundary between two grains, or small crystals, within a larger crystal. A wide variety of grain boundaries can form in a polycrystal depending on factors such growth conditions and thermal treatment. In this talk we will present our first-principles density functional theory based defect studies of SiO2 polymorphs (stishovite, CaCl2-, α-PbO2-, and pyrite-type), Mg2SiO4 polymorphs (forsterite, wadsleyite and ringwoodite) and MgO [1-3]. Briefly, several native point defects including vacancies, interstitials, and their complexes were studied in silica polymorphs upto 200 GPa. Their values increase by a factor of 2 over the entire pressure range studied with large differences in some cases between different phases. The Schottky defects are energetically most favorable at zero pressure whereas O-Frenkel pairs become systematically more favorable at pressures higher than 20 GPa. The geometric and electronic structures of defects and migrating

Reconstruction of large upper eyelid defects with a free tarsal plate graft and a myocutaneous pedicle flap plus a free skin graft.

Science.gov (United States)

Toft, Peter B

2016-01-01

To review and present the results of a one-step method employing a free tarsal plate graft and a myocutaneous pedicle flap plus a free skin graft for reconstruction of large upper eyelid defects after tumour surgery. This was a retrospective case-series of 8 patients who underwent reconstruction of the upper eyelid after tumour removal. The horizontal defect involved 50-75% of the lid (3 pts.), more than 75% (3 pts.), and more than 75% plus the lateral canthus (2 pts.). The posterior lamella was reconstructed with contralateral upper eyelid tarsal plate. The anterior lamella was reconstructed with a laterally based myocutaneous pedicle flap in 7 patients, leaving a raw surface under the brow which was covered with a free skin graft. In 1 patient with little skin left under the brow, the anterior lamella was reconstructed with a bi-pedicle orbicularis muscle flap together with a free skin graft. All patients healed without necrosis, did not suffer from lagophthalmos, achieved reasonable cosmesis, and did not need lubricants. In one patient, a contact lens was necessary for three weeks because of corneal erosion. One patient still needs a contact lens 3 months after excision to avoid eye discomfort. Large upper eyelid defects can be reconstructed with a free tarsal plate graft and a laterally based myocutaneous pedicle flap in combination with a free skin graft. Two-step procedures can probably be avoided in most cases.

Comprehensive comparison of large-scale tissue expression datasets

DEFF Research Database (Denmark)

Santos Delgado, Alberto; Tsafou, Kalliopi; Stolte, Christian

2015-01-01

a comprehensive evaluation of tissue expression data from a variety of experimental techniques and show that these agree surprisingly well with each other and with results from literature curation and text mining. We further found that most datasets support the assumed but not demonstrated distinction between......For tissues to carry out their functions, they rely on the right proteins to be present. Several high-throughput technologies have been used to map out which proteins are expressed in which tissues; however, the data have not previously been systematically compared and integrated. We present......://tissues.jensenlab.org), which makes all the scored and integrated data available through a single user-friendly web interface....

Correlation of cutaneous tension distribution and tissue oxygenation with acute external tissue expansion

Directory of Open Access Journals (Sweden)

Marquardt C

2009-11-01

Full Text Available Abstract Today, the biomechanical fundamentals of skin expansion are based on viscoelastic models of the skin. Although many studies have been conducted in vitro, analyses performed in vivo are rare. Here, we present in vivo measurements of the expansion at the skin surface as well as measurement of the corresponding intracutaneous oxygen partial pressure. In our study the average skin stretching was 24%, with a standard deviation of 11%, excluding age or gender dependency. The measurement of intracutaneous oxygen partial pressure produced strong inter-individual fluctuations, including initial values at the beginning of the measurement, as well as varying individual patient reactions to expansion of the skin. Taken together, we propose that even large defect wounds can be closed successfully using the mass displacement caused by expansion especially in areas where soft, voluminous tissue layers are present.

Modeling of Powder Bed Manufacturing Defects

Science.gov (United States)

Mindt, H.-W.; Desmaison, O.; Megahed, M.; Peralta, A.; Neumann, J.

2018-01-01

Powder bed additive manufacturing offers unmatched capabilities. The deposition resolution achieved is extremely high enabling the production of innovative functional products and materials. Achieving the desired final quality is, however, hampered by many potential defects that have to be managed in due course of the manufacturing process. Defects observed in products manufactured via powder bed fusion have been studied experimentally. In this effort we have relied on experiments reported in the literature and—when experimental data were not sufficient—we have performed additional experiments providing an extended foundation for defect analysis. There is large interest in reducing the effort and cost of additive manufacturing process qualification and certification using integrated computational material engineering. A prerequisite is, however, that numerical methods can indeed capture defects. A multiscale multiphysics platform is developed and applied to predict and explain the origin of several defects that have been observed experimentally during laser-based powder bed fusion processes. The models utilized are briefly introduced. The ability of the models to capture the observed defects is verified. The root cause of the defects is explained by analyzing the numerical results thus confirming the ability of numerical methods to provide a foundation for rapid process qualification.

Esthetic management of mucogingival defects after excision of epulis using laterally positioned flaps.

Science.gov (United States)

Xie, Yu-feng; Shu, Rong; Qian, Jie-lei; Lin, Zhi-kai; Romanos, Georgios E

2015-03-01

Epulis is a benign hyperplasia of the oral soft tissues. Surgical excision always extends to the periosteum and includes scaling of adjacent teeth to remove any possible irritants. The esthetics of the soft tissues may be compromised, however. This article studies three cases in which an immediate laterally positioned flap (LRF) was used to repair mucogingival defects after epulis biopsies. After 24 months, the color and shape of the surgical areas were healthy and stable, nearly complete root coverage was evident, and no lesions reoccurred. For repairing gingival defects after biopsy, LRF appears to be minimally traumatic while promoting esthetic outcomes.

Effect of interaction between irradiation-induced defects and intrinsic defects in the pinning improvement of neutron irradiated YBaCuO sample

International Nuclear Information System (INIS)

Topal, Ugur; Sozeri, Huseyin; Yavuz, Hasbi

2004-01-01

Interaction between the intrinsic (native) defects and the irradiation-induced defects created by neutron irradiation was examined for the YBCO sample. For this purpose, non-superconducting Y-211 phase was included to the Y-123 samples at different contents as a source of large pinning center. The critical current density enhancement with the irradiation for these samples were analysed and then the role of defects on pinning improvement was discussed

Effect of interaction between irradiation-induced defects and intrinsic defects in the pinning improvement of neutron irradiated YBaCuO sample

Energy Technology Data Exchange (ETDEWEB)

Topal, Ugur; Sozeri, Huseyin; Yavuz, Hasbi

2004-08-01

Interaction between the intrinsic (native) defects and the irradiation-induced defects created by neutron irradiation was examined for the YBCO sample. For this purpose, non-superconducting Y-211 phase was included to the Y-123 samples at different contents as a source of large pinning center. The critical current density enhancement with the irradiation for these samples were analysed and then the role of defects on pinning improvement was discussed.

Defects formation and spiral waves in a network of neurons in presence of electromagnetic induction.

Science.gov (United States)

Rostami, Zahra; Jafari, Sajad

2018-04-01

Complex anatomical and physiological structure of an excitable tissue (e.g., cardiac tissue) in the body can represent different electrical activities through normal or abnormal behavior. Abnormalities of the excitable tissue coming from different biological reasons can lead to formation of some defects. Such defects can cause some successive waves that may end up to some additional reorganizing beating behaviors like spiral waves or target waves. In this study, formation of defects and the resulting emitted waves in an excitable tissue are investigated. We have considered a square array network of neurons with nearest-neighbor connections to describe the excitable tissue. Fundamentally, electrophysiological properties of ion currents in the body are responsible for exhibition of electrical spatiotemporal patterns. More precisely, fluctuation of accumulated ions inside and outside of cell causes variable electrical and magnetic field. Considering undeniable mutual effects of electrical field and magnetic field, we have proposed the new Hindmarsh-Rose (HR) neuronal model for the local dynamics of each individual neuron in the network. In this new neuronal model, the influence of magnetic flow on membrane potential is defined. This improved model holds more bifurcation parameters. Moreover, the dynamical behavior of the tissue is investigated in different states of quiescent, spiking, bursting and even chaotic state. The resulting spatiotemporal patterns are represented and the time series of some sampled neurons are displayed, as well.

BMP2-loaded hollow hydroxyapatite microspheres exhibit enhanced osteoinduction and osteogenicity in large bone defects.

Science.gov (United States)

Xiong, Long; Zeng, Jianhua; Yao, Aihua; Tu, Qiquan; Li, Jingtang; Yan, Liang; Tang, Zhiming

2015-01-01

The regeneration of large bone defects is an osteoinductive, osteoconductive, and osteogenic process that often requires a bone graft for support. Limitations associated with naturally autogenic or allogenic bone grafts have demonstrated the need for synthetic substitutes. The present study investigates the feasibility of using novel hollow hydroxyapatite microspheres as an osteoconductive matrix and a carrier for controlled local delivery of bone morphogenetic protein 2 (BMP2), a potent osteogenic inducer of bone regeneration. Hollow hydroxyapatite microspheres (100±25 μm) with a core (60±18 μm) and a mesoporous shell (180±42 m(2)/g surface area) were prepared by a glass conversion technique and loaded with recombinant human BMP2 (1 μg/mg). There was a gentle burst release of BMP2 from microspheres into the surrounding phosphate-buffered saline in vitro within the initial 48 hours, and continued at a low rate for over 40 days. In comparison with hollow hydroxyapatite microspheres without BMP2 or soluble BMP2 without a carrier, BMP2-loaded hollow hydroxyapatite microspheres had a significantly enhanced capacity to reconstitute radial bone defects in rabbit, as shown by increased serum alkaline phosphatase; quick and complete new bone formation within 12 weeks; and great biomechanical flexural strength. These results indicate that BMP2-loaded hollow hydroxyapatite microspheres could be a potential new option for bone graft substitutes in bone regeneration.

A comparative clinico-radiographic study of guided tissue regeneration with bioresorbable membrane and a composite synthetic bone graft for the treatment of periodontal osseous defects

Directory of Open Access Journals (Sweden)

Sumedha Srivastava

2015-01-01

Full Text Available Aim: The aim was to evaluate the bonefill in periodontal osseous defects with the help of guided tissue regeneration, bioresorbable membrane (PerioCol + bone graft (Grabio Glascera in combination and with bonegraft (Grabio Glascera alone. Materials and Methods: The study involved total 30 sites in systemically healthy 19 patients. The parameters for evaluation includes plaque index sulcus bleeding index with one or more periodontal osseous defects having (i probing depth (PD of ≥ 5 mm (ii clinical attachment loss (CAL of ≥ 5 mm and (iii ≥3 mm of radiographic periodontal osseous defect (iv bonefill (v crestal bone loss (vi defect resolution. The study involved the three wall and two wall defects which should be either located interproximally or involving the furcation area. The statistical analysis was done using Statistical Package for Social Sciences, the Wilcoxon signed rank statistic W + for Mann-Whitney U-test. Results: The net gain in PD and CAL after 6 months for Group I ([PerioCol] + [Grabio Glascera] and Group II (Grabio Glascera was 3.94 ± 1.81 mm, 3.57 ± 2.21 mm and 3.94 ± 1.81, 3.57 ± 2.21 mm, respectively. The results of the study for Group I and Group II with regards to mean net bonefill, was 3.25 ± 2.32 (58% mm and 5.14 ± 3.84 (40.26 ± 19.14% mm, crestal bone loss − 0.25 ± 0.68 mm and − 0.79 ± 1.19 mm. Defect resolution 3.50 ± 2.34 mm and 5.93 ± 4.01 mm, respectively. Conclusion: On comparing both the groups together after 6 months of therapy, the results were equally effective for combination of graft and membrane versus bone graft alone since no statistical significant difference was seen between above parameters for both the groups. Thus, both the treatment modalities are comparable and equally effective.

Chitosan-glycerol phosphate/blood implants improve hyaline cartilage repair in ovine microfracture defects.

Science.gov (United States)

Hoemann, Caroline D; Hurtig, Mark; Rossomacha, Evgeny; Sun, Jun; Chevrier, Anik; Shive, Matthew S; Buschmann, Michael D

2005-12-01

one hour postoperatively, chitosan-glycerol phosphate/blood clots showed increased adhesion to the walls of the defects as compared with the blood clots in the untreated microfracture defects. After histological processing, all blood clots in the control microfracture defects had been lost, whereas chitosanglycerol phosphate/blood clot adhered to and was partly retained on the surfaces of the defect. At six months, defects that had been treated with chitosan-glycerol phosphate/blood were filled with significantly more hyaline repair tissue (p cartilage repair compared with microfracture alone by increasing the amount of tissue and improving its biochemical composition and cellular organization.

Displacement cascades and defects annealing in tungsten, Part I: Defect database from molecular dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Setyawan, Wahyu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nandipati, Giridhar [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Roche, Kenneth J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Univ. of Washington, Seattle, WA (United States); Heinisch, Howard L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wirth, Brian D. [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab., Oak Ridge, TN (United States); Kurtz, Richard J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2015-07-01

Molecular dynamics simulations have been used to generate a comprehensive database of surviving defects due to displacement cascades in bulk tungsten. Twenty-one data points of primary knock-on atom (PKA) energies ranging from 100 eV (sub-threshold energy) to 100 keV (~780^×_Ed, where _Ed = 128 eV is the average displacement threshold energy) have been completed at 300 K, 1025 K and 2050 K. Within this range of PKA energies, two regimes of power-law energy-dependence of the defect production are observed. A distinct power-law exponent characterizes the number of Frenkel pairs produced within each regime. The two regimes intersect at a transition energy which occurs at approximately 250^×_Ed. The transition energy also marks the onset of the formation of large self-interstitial atom (SIA) clusters (size 14 or more). The observed defect clustering behavior is asymmetric, with SIA clustering increasing with temperature, while the vacancy clustering decreases. This asymmetry increases with temperature such that at 2050 K (~0.5_Tm) practically no large vacancy clusters are formed, meanwhile large SIA clusters appear in all simulations. The implication of such asymmetry on the long-term defect survival and damage accumulation is discussed. In addition, <100> {110} SIA loops are observed to form directly in the highest energy cascades, while vacancy <100> loops are observed to form at the lowest temperature and highest PKA energies, although the appearance of both the vacancy and SIA loops with Burgers vector of <100> type is relatively rare.

Regeneration of articular cartilage by adipose tissue derived mesenchymal stem cells: perspectives from stem cell biology and molecular medicine.

Science.gov (United States)

Wu, Ling; Cai, Xiaoxiao; Zhang, Shu; Karperien, Marcel; Lin, Yunfeng

2013-05-01

Adipose-derived stem cells (ASCs) have been discovered for more than a decade. Due to the large numbers of cells that can be harvested with relatively little donor morbidity, they are considered to be an attractive alternative to bone marrow derived mesenchymal stem cells. Consequently, isolation and differentiation of ASCs draw great attention in the research of tissue engineering and regenerative medicine. Cartilage defects cause big therapeutic problems because of their low self-repair capacity. Application of ASCs in cartilage regeneration gives hope to treat cartilage defects with autologous stem cells. In recent years, a lot of studies have been performed to test the possibility of using ASCs to re-construct damaged cartilage tissue. In this article, we have reviewed the most up-to-date articles utilizing ASCs for cartilage regeneration in basic and translational research. Our topic covers differentiation of adipose tissue derived mesenchymal stem cells into chondrocytes, increased cartilage formation by co-culture of ASCs with chondrocytes and enhancing chondrogenic differentiation of ASCs by gene manipulation. Copyright © 2012 Wiley Periodicals, Inc.

Large-bandwidth planar photonic crystal waveguides

DEFF Research Database (Denmark)

Søndergaard, Thomas; Lavrinenko, Andrei

2002-01-01

A general design principle is presented for making finite-height photonic crystal waveguides that support leakage-free guidance of light over large frequency intervals. The large bandwidth waveguides are designed by introducing line defects in photonic crystal slabs, where the material in the line...... defect has appropriate dispersion properties relative to the photonic crystal slab material surrounding the line defect. A three-dimensional theoretical analysis is given for large-bandwidth waveguide designs based on a silicon-air photonic crystal slab suspended in air. In one example, the leakage......-free single-mode guidance is found for a large frequency interval covering 60% of the photonic band-gap....

Defect kinetics in novel detector materials

CERN Document Server

MacEvoy, B C

2000-01-01

Silicon particle detectors will be used extensively in experiments at the CERN Large Hadron Collider, where unprecedented particle fluences will cause significant atomic displacement damage. We present a model of the evolution of defect concentrations and consequent electrical behaviour in "novel" detector materials with various oxygen and carbon impurity concentrations. The divacancy-oxygen (V/sub 2/O) defect is identified as the cause of changes in device characteristics during /sup 60/Co gamma irradiation. In the case of hadron irradiation changes in detector doping concentration (N/sub eff/) are dominated by cluster defects, in particular the divacancy (V/sub 2/), which exchange charge directly via a non-Shockley-Read- Hall mechanism. The V/sub 2/O defect also contributes to Ne/sub eff/. This defect is more copiously produced during 24 GeV/c proton irradiation than during 1 MeV neutron irradiation on account of the higher vacancy introduction rate, hence the radiation hardness of materials is more sensiti...

New tools for non-invasive exploration of collagen network in cartilaginous tissue-engineered substitute.

Science.gov (United States)

Henrionnet, Christel; Dumas, Dominique; Hupont, Sébastien; Stoltz, Jean François; Mainard, Didier; Gillet, Pierre; Pinzano, Astrid

2017-01-01

In tissue engineering approaches, the quality of substitutes is a key element to determine its ability to treat cartilage defects. However, in clinical practice, the evaluation of tissue-engineered cartilage substitute quality is not possible due to the invasiveness of the standard procedure, which is to date histology. The aim of this work was to validate a new innovative system performed from two-photon excitation laser adapted to an optical macroscope to evaluate at macroscopic scale the collagen network in cartilage tissue-engineered substitutes in confrontation with gold standard histologic techniques or immunohistochemistry to visualize type II collagen. This system permitted to differentiate the quality of collagen network between ITS and TGF-β1 treatments. Multiscale large field imaging combined to multimodality approaches (SHG-TCSPC) at macroscopical scale represent an innovative and non-invasive technique to monitor the quality of collagen network in cartilage tissue-engineered substitutes before in vivo implantation.

Management of Anterior Skull Base Defect Depending on Its Size and Location

Science.gov (United States)

Bernal-Sprekelsen, Manuel; Rioja, Elena; Enseñat, Joaquim; Enriquez, Karla; Viscovich, Liza; Agredo-Lemos, Freddy Enrique; Alobid, Isam

2014-01-01

Introduction. We present our experience in the reconstruction of these leaks depending on their size and location. Material and Methods. Fifty-four patients who underwent advanced skull base surgery (large defects, >20 mm) and 62 patients with CSF leaks of different origin (small, 2–10 mm, and midsize, 11–20 mm, defects) were included in the retrospective study. Large defects were reconstructed with a nasoseptal pedicled flap positioned on fat and fascia lata. In small and midsized leaks. Fascia lata in an underlay position was used for its reconstruction covered with mucoperiosteum of either the middle or the inferior turbinate. Results. The most frequent etiology for small and midsized defects was spontaneous (48.4%), followed by trauma (24.2%), iatrogenic (5%). The success rate after the first surgical reconstruction was 91% and 98% in large skull base defects and small/midsized, respectively. Rescue surgery achieved 100%. Conclusions. Endoscopic surgery for any type of skull base defect is the gold standard. The size of the defects does not seem to play a significant role in the success rate. Fascia lata and mucoperiosteum of the turbinate allow a two-layer reconstruction of small and midsized defects. For larger skull base defects, a combination of fat, fascia lata, and nasoseptal pedicled flaps provides a successful reconstruction. PMID:24895567

Use of platelet rich fibrin in a fenestration defect around an implant

Directory of Open Access Journals (Sweden)

R Vijayalakshmi

2012-01-01

Full Text Available Guided bone regeneration (GBR in implant therapy is especially useful for implant placement with dehiscence defects or fenestration defects. In alveolar ridges with marked facial/buccal depressions or in knifeedge alveolar crests, the position and direction of fixture placement is restricted. Improvement of alveolar ridge morphology becomes possible with GBR. This article describes a case in which the fenestration defect around an implant was treated by the application of platelet rich fibrin, a second generation platelet concentrate along with bone graft, and guided tissue regeneration membrane.

Residual Defect Density in Random Disks Deposits.

Science.gov (United States)

Topic, Nikola; Pöschel, Thorsten; Gallas, Jason A C

2015-08-03

We investigate the residual distribution of structural defects in very tall packings of disks deposited randomly in large channels. By performing simulations involving the sedimentation of up to 50 × 10(9) particles we find all deposits to consistently show a non-zero residual density of defects obeying a characteristic power-law as a function of the channel width. This remarkable finding corrects the widespread belief that the density of defects should vanish algebraically with growing height. A non-zero residual density of defects implies a type of long-range spatial order in the packing, as opposed to only local ordering. In addition, we find deposits of particles to involve considerably less randomness than generally presumed.

Preparation of dexamethasone-loaded biphasic calcium phosphate nanoparticles/collagen porous composite scaffolds for bone tissue engineering.

Science.gov (United States)

Chen, Ying; Kawazoe, Naoki; Chen, Guoping

2018-02-01

Although bone is regenerative, its regeneration capacity is limited. For bone defects beyond a critical size, further intervention is required. As an attractive strategy, bone tissue engineering (bone TE) has been widely investigated to repair bone defects. However, the rapid and effective bone regeneration of large non-healing defects is still a great challenge. Multifunctional scaffolds having osteoinductivity and osteoconductivity are desirable to fasten functional bone tissue regeneration. In the present study, biomimetic composite scaffolds of collagen and biphasic calcium phosphate nanoparticles (BCP NPs) with a controlled release of dexamethasone (DEX) and the controlled pore structures were prepared for bone TE. DEX was introduced in the BCP NPs during preparation of the BCP NPs and hybridized with collagen scaffolds, which pore structures were controlled by using pre-prepared ice particulates as a porogen material. The composite scaffolds had well controlled and interconnected pore structures, high mechanical strength and a sustained release of DEX. The composite scaffolds showed good biocompatibility and promoted osteogenic differentiation of hMSCs when used for three-dimensional culture of human bone marrow-derived mesenchymal stem cells. Subcutaneous implantation of the composite scaffolds at the dorsa of athymic nude mice demonstrated that they facilitated the ectopic bone tissue regeneration. The results indicated the DEX-loaded BCP NPs/collagen composite scaffolds had high potential for bone TE. Scaffolds play a crucial role for regeneration of large bone defects. Biomimetic scaffolds having the same composition of natural bone and a controlled release of osteoinductive factors are desirable for promotion of bone regeneration. In this study, composite scaffolds of collagen and biphasic CaP nanoparticles (BCP NPs) with a controlled release nature of dexamethasone (DEX) were prepared and their porous structures were controlled by using ice particulates

ILT based defect simulation of inspection images accurately predicts mask defect printability on wafer

Science.gov (United States)

Deep, Prakash; Paninjath, Sankaranarayanan; Pereira, Mark; Buck, Peter

2016-05-01

At advanced technology nodes mask complexity has been increased because of large-scale use of resolution enhancement technologies (RET) which includes Optical Proximity Correction (OPC), Inverse Lithography Technology (ILT) and Source Mask Optimization (SMO). The number of defects detected during inspection of such mask increased drastically and differentiation of critical and non-critical defects are more challenging, complex and time consuming. Because of significant defectivity of EUVL masks and non-availability of actinic inspection, it is important and also challenging to predict the criticality of defects for printability on wafer. This is one of the significant barriers for the adoption of EUVL for semiconductor manufacturing. Techniques to decide criticality of defects from images captured using non actinic inspection images is desired till actinic inspection is not available. High resolution inspection of photomask images detects many defects which are used for process and mask qualification. Repairing all defects is not practical and probably not required, however it's imperative to know which defects are severe enough to impact wafer before repair. Additionally, wafer printability check is always desired after repairing a defect. AIMSTM review is the industry standard for this, however doing AIMSTM review for all defects is expensive and very time consuming. Fast, accurate and an economical mechanism is desired which can predict defect printability on wafer accurately and quickly from images captured using high resolution inspection machine. Predicting defect printability from such images is challenging due to the fact that the high resolution images do not correlate with actual mask contours. The challenge is increased due to use of different optical condition during inspection other than actual scanner condition, and defects found in such images do not have correlation with actual impact on wafer. Our automated defect simulation tool predicts

Structural modeling of tissue-specific mitochondrial alanyl-tRNA synthetase (AARS2 defects predicts differential effects on aminoacylation

Directory of Open Access Journals (Sweden)

Liliya eEuro

2015-02-01

Full Text Available The accuracy of mitochondrial protein synthesis is dependent on the coordinated action of nuclear-encoded mitochondrial aminoacyl-tRNA synthetases (mtARSs and the mitochondrial DNA-encoded tRNAs. The recent advances in whole-exome sequencing have revealed the importance of the mtARS proteins for mitochondrial pathophysiology since nearly every nuclear gene for mtARS (out of 19 is now recognized as a disease gene for mitochondrial disease. Typically, defects in each mtARS have been identified in one tissue-specific disease, most commonly affecting the brain, or in one syndrome. However, mutations in the AARS2 gene for mitochondrial alanyl-tRNA synthetase (mtAlaRS have been reported both in patients with infantile-onset cardiomyopathy and in patients with childhood to adulthood-onset leukoencephalopathy. We present here an investigation of the effects of the described mutations on the structure of the synthetase, in an effort to understand the tissue-specific outcomes of the different mutations.The mtAlaRS differs from the other mtARSs because in addition to the aminoacylation domain, it has a conserved editing domain for deacylating tRNAs that have been mischarged with incorrect amino acids. We show that the cardiomyopathy phenotype results from a single allele, causing an amino acid change p.R592W in the editing domain of AARS2, whereas the leukodystrophy mutations are located in other domains of the synthetase. Nevertheless, our structural analysis predicts that all mutations reduce the aminoacylation activity of the synthetase, because all mtAlaRS domains contribute to tRNA binding for aminoacylation. According to our model, the cardiomyopathy mutations severely compromise aminoacylation whereas partial activity is retained by the mutation combinations found in the leukodystrophy patients. These predictions provide a hypothesis for the molecular basis of the distinct tissue-specific phenotypic outcomes.

Fabrication method, structure, mechanical, and biological properties of decellularized extracellular matrix for replacement of wide bone tissue defects.

Science.gov (United States)

Anisimova, N Y; Kiselevsky, M V; Sukhorukova, I V; Shvindina, N V; Shtansky, D V

2015-09-01

the replacement of wide bone tissue defects. Copyright © 2015 Elsevier Ltd. All rights reserved.

The impact of thickness of resorbable membrane of human origin on the ossification of bone defects: A pathohistologic study

Directory of Open Access Journals (Sweden)

Bubalo Marija

2012-01-01

Full Text Available Background/Aim. A wide range of resorbable and nonresorbable membranes have been investigated over the last two decades. The barrier membrane protects the defect from ingrowth of soft tissue cells and allows bone progenitor cells to develop bone within a blood clot that is formed beneath the barrier membrane. The membranes are applied to reconstruct small bony defect prior to implantation, to cover dehiscences and fenestrations around dental implants. The aim of this study was to evaluate the influence of human resorbable demineralized membrane (RHDM thickness on bone regeneration. Methods. The experiment, approved by Ethical Committee, was performed on 6 dogs and conducted into three phases. Bone defects were created in all the 6 dogs on the left side of the mandible, 8 weeks after extraction of second, third and fourth premolars. One defect was covered with RHDM 100 μ thick, one with RHDM 200 μ thick, and the third defect left empty (control defect. The histopathological analysis was done 2, 4 and 6 months after the surgery. In the third phase samples of bone tissue were taken and subjected to histopathological analysis. Results. In all the 6 dogs the defects treated with RHDM 200 μ thick showed higher level of bone regeneration in comparison with the defect treated with RHDM 100 μ thick and especially with empty defect. Conclusion. Our results demonstrated that the thicker membrane showed the least soft tissue ingrowths and promoted better bone formation at 6 months compared with a thinner one.

Noncanonical Wnt signaling promotes obesity-induced adipose tissue inflammation and metabolic dysfunction independent of adipose tissue expansion.

Science.gov (United States)

Fuster, José J; Zuriaga, María A; Ngo, Doan Thi-Minh; Farb, Melissa G; Aprahamian, Tamar; Yamaguchi, Terry P; Gokce, Noyan; Walsh, Kenneth

2015-04-01

Adipose tissue dysfunction plays a pivotal role in the development of insulin resistance in obese individuals. Cell culture studies and gain-of-function mouse models suggest that canonical Wnt proteins modulate adipose tissue expansion. However, no genetic evidence supports a role for endogenous Wnt proteins in adipose tissue dysfunction, and the role of noncanonical Wnt signaling remains largely unexplored. Here we provide evidence from human, mouse, and cell culture studies showing that Wnt5a-mediated, noncanonical Wnt signaling contributes to obesity-associated metabolic dysfunction by increasing adipose tissue inflammation. Wnt5a expression is significantly upregulated in human visceral fat compared with subcutaneous fat in obese individuals. In obese mice, Wnt5a ablation ameliorates insulin resistance, in parallel with reductions in adipose tissue inflammation. Conversely, Wnt5a overexpression in myeloid cells augments adipose tissue inflammation and leads to greater impairments in glucose homeostasis. Wnt5a ablation or overexpression did not affect fat mass or adipocyte size. Mechanistically, Wnt5a promotes the expression of proinflammatory cytokines by macrophages in a Jun NH2-terminal kinase-dependent manner, leading to defective insulin signaling in adipocytes. Exogenous interleukin-6 administration restores insulin resistance in obese Wnt5a-deficient mice, suggesting a central role for this cytokine in Wnt5a-mediated metabolic dysfunction. Taken together, these results demonstrate that noncanonical Wnt signaling contributes to obesity-induced insulin resistance independent of adipose tissue expansion. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Defects and defect processes in nonmetallic solids

CERN Document Server

Hayes, W

2004-01-01

This extensive survey covers defects in nonmetals, emphasizing point defects and point-defect processes. It encompasses electronic, vibrational, and optical properties of defective solids, plus dislocations and grain boundaries. 1985 edition.

New Technologies for Surgery of the Congenital Cardiac Defect

Directory of Open Access Journals (Sweden)

David Kalfa

2013-07-01

Full Text Available The surgical repair of complex congenital heart defects frequently requires additional tissue in various forms, such as patches, conduits, and valves. These devices often require replacement over a patient’s lifetime because of degeneration, calcification, or lack of growth. The main new technologies in congenital cardiac surgery aim at, on the one hand, avoiding such reoperations and, on the other hand, improving long-term outcomes of devices used to repair or replace diseased structural malformations. These technologies are: 1 new patches: CorMatrix® patches made of decellularized porcine small intestinal submucosa extracellular matrix; 2 new devices: the Melody® valve (for percutaneous pulmonary valve implantation and tissue-engineered valved conduits (either decellularized scaffolds or polymeric scaffolds; and 3 new emerging fields, such as antenatal corrective cardiac surgery or robotically assisted congenital cardiac surgical procedures. These new technologies for structural malformation surgery are still in their infancy but certainly present great promise for the future. But the translation of these emerging technologies to routine health care and public health policy will also largely depend on economic considerations, value judgments, and political factors.

Key Questions in Building Defect Prediction Models in Practice

Science.gov (United States)

Ramler, Rudolf; Wolfmaier, Klaus; Stauder, Erwin; Kossak, Felix; Natschläger, Thomas

The information about which modules of a future version of a software system are defect-prone is a valuable planning aid for quality managers and testers. Defect prediction promises to indicate these defect-prone modules. However, constructing effective defect prediction models in an industrial setting involves a number of key questions. In this paper we discuss ten key questions identified in context of establishing defect prediction in a large software development project. Seven consecutive versions of the software system have been used to construct and validate defect prediction models for system test planning. Furthermore, the paper presents initial empirical results from the studied project and, by this means, contributes answers to the identified questions.

Expression of defective measles virus genes in brain tissues of patients with subacute sclerosing panencephalitis

International Nuclear Information System (INIS)

Baczko, K.; Liebert, U.G.; Billeter, M.; Cattaneo, R.; Budka, H.; Ter Meulen, V.

1986-01-01

The persistence of measles virus in selected areas of the brains of four patients with subacute sclerosing panencephalitis (SSPE) was characterized by immunohistological and biochemical techniques. The five measles virus structural proteins were never simultaneously detectable in any of the bran sections. Nucleocapsid proteins and phosphoproteins were found in every diseased brain area, whereas hemagglutinin protein was detected in two cases, fusion protein was detected in three cases, and matrix protein was detected in only one case. Also, it could be shown that the amounts of measles virus RNA in the brains differed from patient to patient and in the different regions investigated. In all patients, plus-strand RNAs specific for these five viral genes could be detected. However, the amounts of fusion and hemagglutinin mRNAs were low compared with the amounts in lytically infected cells. The presence of particular measles virus RNAs in SSPE-infected brains did not always correlate with mRNA activity. In in vitro translations, the matrix protein was produced in only one case, and the hemagglutinin protein was produced in none. These results indicate that measles virus persistence in SSPE is correlated with different defects of several genes which probably prevent assembly of viral particles in SSPE-infected brain tissue

Chitosan-glycerol phosphate/blood implants elicit hyaline cartilage repair integrated with porous subchondral bone in microdrilled rabbit defects.

Science.gov (United States)

Hoemann, C D; Sun, J; McKee, M D; Chevrier, A; Rossomacha, E; Rivard, G-E; Hurtig, M; Buschmann, M D

2007-01-01

We have previously shown that microfractured ovine defects are repaired with more hyaline cartilage when the defect is treated with in situ-solidified implants of chitosan-glycerol phosphate (chitosan-GP) mixed with autologous whole blood. The objectives of this study were (1) to characterize chitosan-GP/blood clots in vitro, and (2) to develop a rabbit marrow stimulation model in order to determine the effects of the chitosan-GP/blood implant and of debridement on the formation of incipient cartilage repair tissue. Blood clots were characterized by histology and in vitro clot retraction tests. Bilateral 3.5 x 4 mm trochlear defects debrided into the calcified layer were pierced with four microdrill holes and filled with a chitosan-GP/blood implant or allowed to bleed freely as a control. At 1 day post-surgery, initial defects were characterized by histomorphometry (n=3). After 8 weeks of repair, osteochondral repair tissues between or through the drill holes were evaluated by histology, histomorphometry, collagen type II expression, and stereology (n=16). Chitosan-GP solutions structurally stabilized the blood clots by inhibiting clot retraction. Treatment of drilled defects with chitosan-GP/blood clots led to the formation of a more integrated and hyaline repair tissue above a more porous and vascularized subchondral bone plate compared to drilling alone. Correlation analysis of repair tissue between the drill holes revealed that the absence of calcified cartilage and the presence of a porous subchondral bone plate were predictors of greater repair tissue integration with subchondral bone (Phyaline and integrated repair tissue associated with a porous subchondral bone replete with blood vessels. Concomitant regeneration of a vascularized bone plate during cartilage repair could provide progenitors, anabolic factors and nutrients that aid in the formation of hyaline cartilage.

Automatic classification of blank substrate defects

Science.gov (United States)

Boettiger, Tom; Buck, Peter; Paninjath, Sankaranarayanan; Pereira, Mark; Ronald, Rob; Rost, Dan; Samir, Bhamidipati

2014-10-01

Mask preparation stages are crucial in mask manufacturing, since this mask is to later act as a template for considerable number of dies on wafer. Defects on the initial blank substrate, and subsequent cleaned and coated substrates, can have a profound impact on the usability of the finished mask. This emphasizes the need for early and accurate identification of blank substrate defects and the risk they pose to the patterned reticle. While Automatic Defect Classification (ADC) is a well-developed technology for inspection and analysis of defects on patterned wafers and masks in the semiconductors industry, ADC for mask blanks is still in the early stages of adoption and development. Calibre ADC is a powerful analysis tool for fast, accurate, consistent and automatic classification of defects on mask blanks. Accurate, automated classification of mask blanks leads to better usability of blanks by enabling defect avoidance technologies during mask writing. Detailed information on blank defects can help to select appropriate job-decks to be written on the mask by defect avoidance tools [1][4][5]. Smart algorithms separate critical defects from the potentially large number of non-critical defects or false defects detected at various stages during mask blank preparation. Mechanisms used by Calibre ADC to identify and characterize defects include defect location and size, signal polarity (dark, bright) in both transmitted and reflected review images, distinguishing defect signals from background noise in defect images. The Calibre ADC engine then uses a decision tree to translate this information into a defect classification code. Using this automated process improves classification accuracy, repeatability and speed, while avoiding the subjectivity of human judgment compared to the alternative of manual defect classification by trained personnel [2]. This paper focuses on the results from the evaluation of Automatic Defect Classification (ADC) product at MP Mask

Reconstruction of large diaphyseal bone defect by simplified bone transport over nail technique: A 7-case series.

Science.gov (United States)

Ferchaud, F; Rony, L; Ducellier, F; Cronier, P; Steiger, V; Hubert, L

2017-11-01

Reconstruction of large diaphyseal bone defect is complex and the complications rate is high. This study aimed to assess a simplified technique of segmental bone transport by monorail external fixator over an intramedullary nail.A prospective study included 7 patients: 2 femoral and 5 tibial defects. Mean age was 31years (range: 16-61years). Mean follow-up was 62 months (range: 46-84months). Defects were post-traumatic, with a mean length of 7.2cm (range: 4 to 9.5cm). For 3 patients, reconstruction followed primary failure. In 4 cases, a covering flap was necessary. Transport used an external fixator guided by an intramedullary nail, at a rate of 1mm per day. One pin was implanted on either side of the distraction zone. The external fixator was removed 1 month after bone contact at the docking site. Mean bone transport time was 11 weeks (range: 7-15 weeks). Mean external fixation time was 5.1months (range: 3.5 to 8months). Full weight-bearing was allowed 5.7months (range: 3.5-13months) after initiation of transport. In one patient, a pin had to be repositioned. In 3 patients, the transported segment re-ascended after external fixatorablation, requiring repeat external fixation and resumption of transport. There was just 1 case of superficial pin infection. Reconstruction quality was considered "excellent" on the Paley-Marr criteria in 6 cases. The present technique provided excellent reconstruction quality in 6 of the 7 cases. External fixation time was shorter and resumption of weight-bearing earlier than with other reconstruction techniques, notably including bone autograft, vascularized bone graft or the induced membrane technique. Nailing facilitated control of limb axis and length. The complications rate was 50%, comparable to other techniques. This study raises the question of systematic internal fixation of the docking site, to avoid any mobilization of the transported segment. The bone quality, axial control and rapidity shown by the present technique make

A Stereological Method for the Quantitative Evaluation of Cartilage Repair Tissue

Science.gov (United States)

Nyengaard, Jens Randel; Lind, Martin; Spector, Myron

2015-01-01

Objective To implement stereological principles to develop an easy applicable algorithm for unbiased and quantitative evaluation of cartilage repair. Design Design-unbiased sampling was performed by systematically sectioning the defect perpendicular to the joint surface in parallel planes providing 7 to 10 hematoxylin–eosin stained histological sections. Counting windows were systematically selected and converted into image files (40-50 per defect). The quantification was performed by two-step point counting: (1) calculation of defect volume and (2) quantitative analysis of tissue composition. Step 2 was performed by assigning each point to one of the following categories based on validated and easy distinguishable morphological characteristics: (1) hyaline cartilage (rounded cells in lacunae in hyaline matrix), (2) fibrocartilage (rounded cells in lacunae in fibrous matrix), (3) fibrous tissue (elongated cells in fibrous tissue), (4) bone, (5) scaffold material, and (6) others. The ability to discriminate between the tissue types was determined using conventional or polarized light microscopy, and the interobserver variability was evaluated. Results We describe the application of the stereological method. In the example, we assessed the defect repair tissue volume to be 4.4 mm3 (CE = 0.01). The tissue fractions were subsequently evaluated. Polarized light illumination of the slides improved discrimination between hyaline cartilage and fibrocartilage and increased the interobserver agreement compared with conventional transmitted light. Conclusion We have applied a design-unbiased method for quantitative evaluation of cartilage repair, and we propose this algorithm as a natural supplement to existing descriptive semiquantitative scoring systems. We also propose that polarized light is effective for discrimination between hyaline cartilage and fibrocartilage. PMID:26069715

Guided bone regeneration : the influence of barrier membranes on bone grafts and bone defects

NARCIS (Netherlands)

Gielkens, Pepijn Frans Marie

2008-01-01

Guided bone regeneration (GBR) can be described as the use of a barrier membrane to provide a space available for new bone formation in a bony defect. The barrier membrane protects the defect from in-growth of soft tissue cells and allows bone progenitor cells to develop bone within a blood clot

Artificial membrane-binding proteins stimulate oxygenation of stem cells during engineering of large cartilage tissue

Science.gov (United States)

Armstrong, James P. K.; Shakur, Rameen; Horne, Joseph P.; Dickinson, Sally C.; Armstrong, Craig T.; Lau, Katherine; Kadiwala, Juned; Lowe, Robert; Seddon, Annela; Mann, Stephen; Anderson, J. L. Ross; Perriman, Adam W.; Hollander, Anthony P.

2015-06-01

Restricted oxygen diffusion can result in central cell necrosis in engineered tissue, a problem that is exacerbated when engineering large tissue constructs for clinical application. Here we show that pre-treating human mesenchymal stem cells (hMSCs) with synthetic membrane-active myoglobin-polymer-surfactant complexes can provide a reservoir of oxygen capable of alleviating necrosis at the centre of hyaline cartilage. This is achieved through the development of a new cell functionalization methodology based on polymer-surfactant conjugation, which allows the delivery of functional proteins to the hMSC membrane. This new approach circumvents the need for cell surface engineering using protein chimerization or genetic transfection, and we demonstrate that the surface-modified hMSCs retain their ability to proliferate and to undergo multilineage differentiation. The functionalization technology is facile, versatile and non-disruptive, and in addition to tissue oxygenation, it should have far-reaching application in a host of tissue engineering and cell-based therapies.

A clinical case of single-stage correction of penetration combined orofacial defect with two microsurgical autografts

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A. D. Kaprin

2015-01-01

Full Text Available After surgical treatment for locally advanced oral tumors with resection of soft tissues, mucosal membrane, and facial skeletal structures, there are penetration combined defects, removal of which is a challenge for reconstructive surgeons. Mandibular repair is one of the problems in the correction of combined oral defects. Surgeons use different grafts to remove mandibular defects. One-flap transplantation does not always solve all reconstruction problems and ensure the repair of the mucosal membrane, a soft-tissue component, skin integuments, and facial skeleton.The authors describe a clinical case of successful single-stage correction of penetration combined orofacial defect after resection of the tongue, mouth floor, en bloc resection of the lower jaw and mental soft tissues, bilateral cervical supramyochoroidal lymphadenectomy, stage LCL CM mandibular defect formation after J. Boyd, by using two microsurgical autografts (a peroneal skin-muscle-skin autograft and a radial skin-fascia one in a 39-year-old female patient clinically diagnosed with carcinoma of the left mandibular alveolar ridge mucosa, Stage IVA (T4аN0M0.The Department of Microsurgery, P.A. Herzen Moscow Oncology Research Institute, Ministry of Health of Russia, has gained experience in comprehensively correcting extensive combined maxillofacial defects with two or more grafts in 27 patients who underwent autografting with a total of 73 flaps. The most functionally incapacitating and life-incompatible defect was removed at Stage 1 of reconstructive treatment. Delayed reconstruction was made after a complex of specialized antitumor therapy and assessment of treatment results in the absence of progressive growth. A great problem during multi-stage defect correction is presented by the lack of recipient vessels after cervical lymphadenectomy, the presence of soft tissue scar changes, trismus, temporomandibular joint ankylosis, contractures and displacement of the edges of the

Experimental study of defect power reactor fuel. Final report

International Nuclear Information System (INIS)

Forsyth, R.S.; Jonsson, T.

1982-01-01

Two BWR fuel rods, one intact and one defect, with the same manufacturing and irradiation data have been examined in a comparative study. The defect rod has been irradiated in a defect condition during approximately one reactor cycle and has consequently some secondary defects. The defect rod has two penetrating defects at a distance of about 1.5 meters from each other. Comparison with the intact rod shows a large Cs loss from the defect rod, especially between the cladding defects, where the loss is measured to about 30 %. The leachibility in deionized water is higher for Cs, U and Cm for fuel from the defect rod. The leaching results are more complex for Sr-90, Pu and Am. The fuel in the defect rod has undergone a change of structure with gain growth and formation of oriented fuel structure. The cladding of the defect rod is hydrided locally in some parts of the lower part of the rod and furthermore over a more extended region near the end of the rod. (Authors)

A histopathologic investigation on the effects of electrical stimulation on periodontal tissue regeneration in experimental bony defects in dogs.

Science.gov (United States)

Kaynak, Deniz; Meffert, Roland; Günhan, Meral; Günhan, Omer

2005-12-01

One endpoint of periodontal therapy is to regenerate the structure lost due to periodontal disease. In the periodontium, gingival epithelium is regenerated by oral epithelium. Underlying connective tissue, periodontal ligament, bone, and cementum are derived from connective tissue. Primitive connective tissue cells may develop into osteoblasts and cementoblasts, which form bone and cementum. Several procedural advances may support these regenerations; however, the regeneration of alveolar bone does not always occur. Therefore, bone stimulating factors are a main topic for periodontal reconstructive research. The present study was designed to examine histopathologically whether the application of an electrical field could demonstrate enhanced alveolar and cementum regeneration and modify tissue factors. Seven beagle dogs were used for this experiment. Mandibular left and right sides served as control and experimental sides, respectively, and 4-walled intrabony defects were created bilaterally between the third and fourth premolars. The experimental side was treated with a capacitively coupled electrical field (CCEF) (sinusoidal wave, 60 kHz, and 5 V peak-to-peak), applied for 14 hours per day. The following measurements were performed on the microphotographs: 1) the distance from the cemento-enamel junction to the apical notch (CEJ-AN) and from the crest of newly formed bone (alveolar ridge) to the apical notch (AR-AN); 2) the thickness of new cementum in the apical notch region; and 3) the length of junctional epithelium. The following histopathologic parameters were assessed by a semiquantitative subjective method: 1) inflammatory cell infiltration (ICI); 2) cellular activity of the periodontal ligament; 3) number and morphology of osteoclasts; 4) resorption lacunae; and 5) osteoblastic activity. The results showed that the quantity of new bone fill and the mean value of the thickness of the cementum were significantly higher for the experimental side (P 0

Early rehabilitation of facial defects using interim removable prostheses: A clinical case report

Directory of Open Access Journals (Sweden)

Vivekanandhan Ramkumar

2013-01-01

Full Text Available Surgical resection of neoplasms or malformations of the face may result in defects that are not amenable to immediate surgical reconstruction. Such defects can have a severe adverse effect on patient perceptions of body image and self-esteem. In these cases, the use of an interim removable facial prosthesis can offer a rapid alternative treatment solution. The patient may then resume social interactions more comfortably while permitting easy access to the facial defect to observe tissue healing while awaiting definitive rehabilitation. This article presents a case report describing the use of interim nasal prostheses to provide rapid patient rehabilitation of facial defects.

Nanotechnology in bone tissue engineering.

Science.gov (United States)

Walmsley, Graham G; McArdle, Adrian; Tevlin, Ruth; Momeni, Arash; Atashroo, David; Hu, Michael S; Feroze, Abdullah H; Wong, Victor W; Lorenz, Peter H; Longaker, Michael T; Wan, Derrick C

2015-07-01

Nanotechnology represents a major frontier with potential to significantly advance the field of bone tissue engineering. Current limitations in regenerative strategies include impaired cellular proliferation and differentiation, insufficient mechanical strength of scaffolds, and inadequate production of extrinsic factors necessary for efficient osteogenesis. Here we review several major areas of research in nanotechnology with potential implications in bone regeneration: 1) nanoparticle-based methods for delivery of bioactive molecules, growth factors, and genetic material, 2) nanoparticle-mediated cell labeling and targeting, and 3) nano-based scaffold construction and modification to enhance physicochemical interactions, biocompatibility, mechanical stability, and cellular attachment/survival. As these technologies continue to evolve, ultimate translation to the clinical environment may allow for improved therapeutic outcomes in patients with large bone deficits and osteodegenerative diseases. Traditionally, the reconstruction of bony defects has relied on the use of bone grafts. With advances in nanotechnology, there has been significant development of synthetic biomaterials. In this article, the authors provided a comprehensive review on current research in nanoparticle-based therapies for bone tissue engineering, which should be useful reading for clinicians as well as researchers in this field. Copyright © 2015 Elsevier Inc. All rights reserved.

3D Volumetric Modeling and Microvascular Reconstruction of Irradiated Lumbosacral Defects After Oncologic Resection

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Emilio Garcia-Tutor

2016-12-01

Full Text Available Background: Locoregional flaps are sufficient in most sacral reconstructions. However, large sacral defects due to malignancy necessitate a different reconstructive approach, with local flaps compromised by radiation and regional flaps inadequate for broad surface areas or substantial volume obliteration. In this report, we present our experience using free muscle transfer for volumetric reconstruction in such cases, and demonstrate 3D haptic models of the sacral defect to aid preoperative planning.Methods: Five consecutive patients with irradiated sacral defects secondary to oncologic resections were included, surface area ranging from 143-600cm2. Latissimus dorsi-based free flap sacral reconstruction was performed in each case, between 2005 and 2011. Where the superior gluteal artery was compromised, the subcostal artery was used as a recipient vessel. Microvascular technique, complications and outcomes are reported. The use of volumetric analysis and 3D printing is also demonstrated, with imaging data converted to 3D images suitable for 3D printing with Osirix software (Pixmeo, Geneva, Switzerland. An office-based, desktop 3D printer was used to print 3D models of sacral defects, used to demonstrate surface area and contour and produce a volumetric print of the dead space needed for flap obliteration. Results: The clinical series of latissimus dorsi free flap reconstructions is presented, with successful transfer in all cases, and adequate soft-tissue cover and volume obliteration achieved. The original use of the subcostal artery as a recipient vessel was successfully achieved. All wounds healed uneventfully. 3D printing is also demonstrated as a useful tool for 3D evaluation of volume and dead-space.Conclusion: Free flaps offer unique benefits in sacral reconstruction where local tissue is compromised by irradiation and tumor recurrence, and dead-space requires accurate volumetric reconstruction. We describe for the first time the use of

Estimation of sensitivity of island fasciocutaneous neurovascular medial plantar flap in the reconstruction of soft tissue defects in calcaneal region

Directory of Open Access Journals (Sweden)

Jevtović Dobrica

2002-01-01

Full Text Available The soft tissue cover in the calcaneal region represents one of the great problems in the reconstructive surgery. The distant skin, muscle and musculocutaneous flaps are subjected to ulcers even with the orthopedic shoes. The island fasciocutaneus mid sole neurocutaneous flap can be a good substitute for the soft tissue cover due to its anatomic structure. The flap has the required dimensions, sticks well to the bone and the movements and mobility of the patient is unrestricted. This paper analyses the sensitivity of the transposed flap and the sole distal to the secondary defect observed in 30 patients. The evaluation was made after tactile tests, two-point discrimination test, the warm-cold test, the electrostatus of medial plantar nerve (MPN, and the ninhydrin test. All the tests, including the electrostatus MPN, done after 3 weeks and 3 months after the surgery, showed successful recovery of sensitivity in the transposed medial plantar flap. The results monitored after three months showed that the speed of the neural conduction recovery was 70% of normal neural reaction speed of the MPN. The modified operative techniques provide safe dissection of the plantar nerve with minimal neuropraxia. The postoperative recovery of sensitivity was more rapid, and without loss of sensitivity on the sole.

[Ultrasound scanning of the distraction regenerate in case of multilocus elongation of the fragments in patients with defects of long bones].

Science.gov (United States)

Menshikova, T I; Borzunov, D Iu; Dolganova, T I

2014-01-01

It was done ultrasound examination of distraction regenerates in patients with defect of bone tissue. The first group included 4 patients who had the size of congenital bone tissue defect 15.8±8.1 cm; the second group (3 patients) included posttraumatic defects with defect size 11.75±3.6 cm; the third group (4 patients) included posttraumatic defects with defect size 11±5.3 cm. It was discovered the particularities of distraction regenerate structural condition in case of low level of reparative osteogenesis. In the first group "ischemic" regenerate was characterized by slow formation of bone trabecules. In the second group "ischemic" regenerate had one or two hypo-echogenic cystic-like formations in the intermediate regenerate area. All patients of the third group had organotypic remodeling of the regenerate according to terms of distraction and fixation.

A comparative evaluation of freeze-dried bone allograft with and without bioabsorbable guided tissue regeneration membrane Healiguide® in the treatment of Grade II furcation defects: A clinical study

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Deept Jain

2015-01-01

Full Text Available Background: Furcation defects represent one of the most demanding therapeutic challenges for periodontal therapy. Various treatment modalities have been tried with different success rates. The present study was undertaken to evaluate the efficacy of freeze-dried bone allograft (FDBA with and without bioabsorbable guided tissue regeneration (GTR membrane Healiguide® in the treatment of Grade II furcation defects. Materials and Methods: Ten patients with bilateral Grade II furcation defects were selected for the study. After phase I therapy, subjects were divided into two arms and treated in a split-mouth design. Ten defects were treated with FDBA alone in the control arm. Ten defects were treated with FDBA in conjunction with bioabsorbable GTR membrane Healiguide® in test arm. Clinical parameters like plaque index, gingival index, vertical probing depth, horizontal probing depth, and relative attachment level (RAL were assessed at baseline, 3 months, and 6 months postoperatively. Results: At 6 months, clinical improvement was seen in both the arms with mean pocket depth reduction of 1.2 ± 1.032 mm and 1.7 ± 0.948 mm and mean horizontal probing depth reduction being 2.1 ± 1.969 mm and 1.6 ± 1.264 mm in control and test arm, respectively. Both surgical procedures resulted in a statistically significant reduction in vertical and horizontal probing depths. Conclusion: Both the arms demonstrated a significant improvement in the probing depth, horizontal furcation depth, and RAL at 6 months postsurgery in the treatment of Grade II furcation defects. However, on the intergroup comparison, there was no statistically significant difference in the results achieved between two arms.

Tri-layered composite plug for the repair of osteochondral defects: in vivo study in sheep

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Altug Yucekul

2017-04-01

Full Text Available Cartilage defects are a source of pain, immobility, and reduced quality of life for patients who have acquired these defects through injury, wear, or disease. The avascular nature of cartilage tissue adds to the complexity of cartilage tissue repair or regeneration efforts. The known limitations of using autografts, allografts, or xenografts further add to this complexity. Autologous chondrocyte implantation or matrix-assisted chondrocyte implantation techniques attempt to introduce cultured cartilage cells to defect areas in the patient, but clinical success with these are impeded by the avascularity of cartilage tissue. Biodegradable, synthetic scaffolds capable of supporting local cells and overcoming the issue of poor vascularization would bypass the issues of current cartilage treatment options. In this study, we propose a biodegradable, tri-layered (poly(glycolic acid mesh/poly(l-lactic acid-colorant tidemark layer/collagen Type I and ceramic microparticle-coated poly(l-lactic acid-poly(ϵ-caprolactone monolith osteochondral plug indicated for the repair of cartilage defects. The porous plug allows the continual transport of bone marrow constituents from the subchondral layer to the cartilage defect site for a more effective repair of the area. Assessment of the in vivo performance of the implant was conducted in an ovine model (n = 13. In addition to a control group (no implant, one group received the implant alone (Group A, while another group was supplemented with hyaluronic acid (0.8 mL at 10 mg/mL solution; Group B. Analyses performed on specimens from the in vivo study revealed that the implant achieves cartilage formation within 6 months. No adverse tissue reactions or other complications were reported. Our findings indicate that the porous biocompatible implant seems to be a promising treatment option for the cartilage repair.

Primary biochemical defect in copper metabolism in mice with a recessive X-linked mutation analogous to Menkes' disease in man

International Nuclear Information System (INIS)

Prins, H.W.; Hamer, C.J.A. van den.

1979-01-01

The defect in Menkes' disease in man is identical to that in Brindled mice. The defect manifests itself in a accumulation of copper in some tissues, such as renal, intestinal (mucosa and muscle), pancreatic, osseous, muscular, and dermal. Hence a fatal copper deficiency results in other tissues (e.g., hepatic). The copper transport through the intestine is impaired and copper, which circumvents the block in the copper resorption, is irreversibly trapped in the above-mentioned, copper accumulating tissues where it is bound to a cytoplasmatic protein with molecular weight 10,000 daltons, probably the primary cytoplasmatic copper transporting protein. This protein shows a Cu-S absorption band at 250 nm, and the copper:protein ratio is increased. Such copper rich protein was found neither in the kidneys of the unaffected mica nor in the liver of the mice that do have the defect. Three models of the primary defect in Menkes' disease are proposed

Evaluation of autogenous PRGF+β-TCP with or without a collagen membrane on bone formation and implant osseointegration in large size bone defects. A preclinical in vivo study.

Science.gov (United States)

Batas, Leonidas; Stavropoulos, Andreas; Papadimitriou, Serafim; Nyengaard, Jens R; Konstantinidis, Antonios

2016-08-01

The aim of this study was to evaluate whether the adjunctive use of a collagen membrane enhances bone formation and implant osseointegration in non-contained defects grafted with chair-side prepared autologous platelet-rich growth factor (PRGF) adsorbed on a β-TCP particulate carrier. Large box-type defects (10 × 6 mm; W × D) were prepared in the edentulated and completely healed mandibles of six Beagles dogs. An implant with moderately rough surface was placed in the center of each defect leaving the coronal 6 mm of the implant not covered with bone. The remaining defect space was then filled out with chair-side prepared autologous PRGF adsorbed on β-TCP particles and either covered with a collagen membrane (PRGF/β-TCP+CM) (6 defects) or left without a membrane (PRGF/β-TCP) (5 defects). Histology 4 months post-op showed new lamellar and woven bone formation encompassing almost entirely the defect and limited residual β-TCP particles. Extent of osseointegration of the previously exposed portion of the implants varied, but in general was limited. Within the defect, new mineralized bone (%) averaged 43.2 ± 9.86 vs. 39.9 ± 13.7 in the PRGF/β-TCP+CM and PRGF/β-TCP group (P = 0.22) and relative mineralized bone-to-implant contact (%) averaged 26.2 ± 16.45 vs. 35.91 ± 24.45, respectively (P = 0.5). First, bone-to-implant contact from the implant top was 4.1 ± 1.5 and 3.2 ± 2.3 (P = 0.9), in the PRGF/β-TCP+CM and PRGF/β-TCP group, respectively. Implantation of chair-side prepared autologous PRGF adsorbed on a β-TCP carrier in non-contained peri-implant defects resulted in large amounts of bone regeneration, but osseointegration was limited. Provisions for GBR with a collagen membrane did not significantly enhance bone regeneration or implant osseointegration. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Optical coherence tomography use in the diagnosis of enamel defects

Science.gov (United States)

Al-Azri, Khalifa; Melita, Lucia N.; Strange, Adam P.; Festy, Frederic; Al-Jawad, Maisoon; Cook, Richard; Parekh, Susan; Bozec, Laurent

2016-03-01

Molar incisor hypomineralization (MIH) affects the permanent incisors and molars, whose undermineralized matrix is evidenced by lesions ranging from white to yellow/brown opacities to crumbling enamel lesions incapable of withstanding normal occlusal forces and function. Diagnosing the condition involves clinical and radiographic examination of these teeth, with known limitations in determining the depth extent of the enamel defects in particular. Optical coherence tomography (OCT) is an emerging hard and soft tissue imaging technique, which was investigated as a new potential diagnostic method in dentistry. A comparison between the diagnostic potential of the conventional methods and OCT was conducted. Compared to conventional imaging methods, OCT gave more information on the structure of the enamel defects as well as the depth extent of the defects into the enamel structure. Different types of enamel defects were compared, each type presenting a unique identifiable pattern when imaged using OCT. Additionally, advanced methods of OCT image analysis including backscattered light intensity profile analysis and enface reconstruction were performed. Both methods confirmed the potential of OCT in enamel defects diagnosis. In conclusion, OCT imaging enabled the identification of the type of enamel defect and the determination of the extent of the enamel defects in MIH with the advantage of being a radiation free diagnostic technique.

Rapid prototyping technology and its application in bone tissue engineering.

Science.gov (United States)

Yuan, Bo; Zhou, Sheng-Yuan; Chen, Xiong-Sheng

Bone defects arising from a variety of reasons cannot be treated effectively without bone tissue reconstruction. Autografts and allografts have been used in clinical application for some time, but they have disadvantages. With the inherent drawback in the precision and reproducibility of conventional scaffold fabrication techniques, the results of bone surgery may not be ideal. This is despite the introduction of bone tissue engineering which provides a powerful approach for bone repair. Rapid prototyping technologies have emerged as an alternative and have been widely used in bone tissue engineering, enhancing bone tissue regeneration in terms of mechanical strength, pore geometry, and bioactive factors, and overcoming some of the disadvantages of conventional technologies. This review focuses on the basic principles and characteristics of various fabrication technologies, such as stereolithography, selective laser sintering, and fused deposition modeling, and reviews the application of rapid prototyping techniques to scaffolds for bone tissue engineering. In the near future, the use of scaffolds for bone tissue engineering prepared by rapid prototyping technology might be an effective therapeutic strategy for bone defects.

Rapid prototyping technology and its application in bone tissue engineering*

Science.gov (United States)

YUAN, Bo; ZHOU, Sheng-yuan; CHEN, Xiong-sheng

2017-01-01

Bone defects arising from a variety of reasons cannot be treated effectively without bone tissue reconstruction. Autografts and allografts have been used in clinical application for some time, but they have disadvantages. With the inherent drawback in the precision and reproducibility of conventional scaffold fabrication techniques, the results of bone surgery may not be ideal. This is despite the introduction of bone tissue engineering which provides a powerful approach for bone repair. Rapid prototyping technologies have emerged as an alternative and have been widely used in bone tissue engineering, enhancing bone tissue regeneration in terms of mechanical strength, pore geometry, and bioactive factors, and overcoming some of the disadvantages of conventional technologies. This review focuses on the basic principles and characteristics of various fabrication technologies, such as stereolithography, selective laser sintering, and fused deposition modeling, and reviews the application of rapid prototyping techniques to scaffolds for bone tissue engineering. In the near future, the use of scaffolds for bone tissue engineering prepared by rapid prototyping technology might be an effective therapeutic strategy for bone defects. PMID:28378568

Developmental Defects of Caenorhabditis elegans Lacking Branched-chain α-Ketoacid Dehydrogenase Are Mainly Caused by Monomethyl Branched-chain Fatty Acid Deficiency.

Science.gov (United States)

Jia, Fan; Cui, Mingxue; Than, Minh T; Han, Min

2016-02-05

Branched-chain α-ketoacid dehydrogenase (BCKDH) catalyzes the critical step in the branched-chain amino acid (BCAA) catabolic pathway and has been the focus of extensive studies. Mutations in the complex disrupt many fundamental metabolic pathways and cause multiple human diseases including maple syrup urine disease (MSUD), autism, and other related neurological disorders. BCKDH may also be required for the synthesis of monomethyl branched-chain fatty acids (mmBCFAs) from BCAAs. The pathology of MSUD has been attributed mainly to BCAA accumulation, but the role of mmBCFA has not been evaluated. Here we show that disrupting BCKDH in Caenorhabditis elegans causes mmBCFA deficiency, in addition to BCAA accumulation. Worms with deficiency in BCKDH function manifest larval arrest and embryonic lethal phenotypes, and mmBCFA supplementation suppressed both without correcting BCAA levels. The majority of developmental defects caused by BCKDH deficiency may thus be attributed to lacking mmBCFAs in worms. Tissue-specific analysis shows that restoration of BCKDH function in multiple tissues can rescue the defects, but is especially effective in neurons. Taken together, we conclude that mmBCFA deficiency is largely responsible for the developmental defects in the worm and conceivably might also be a critical contributor to the pathology of human MSUD. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

The volume of fluid injected into the tissue expander and the tissue expansion

Directory of Open Access Journals (Sweden)

Mahmood Omranifard

2014-01-01

Full Text Available Background: Replacement of the lost tissue is the major concerns of the plastic surgeons. Expanded area should be coherent with the surrounding tissue. Tissue expansion technique is the reforming methods the skin tissue scarcities. Several methods for tissue expansion are available; including usage of silicon balloon and injecting fluid into the tissue expander. Materials and Methods: In a clinical trial study, 35 patients, with burn scars, in the face, skull and neck area were studied. We provided a tissue expander device with capacities of 125, 250 and 350cc. Fluid was injected inside the device, 3 consecutive weeks with 1-week interval. After 3 months the device was set out and the tissue expansion was measured using a transparent board and the results were analyzed. Multiple regression was done by SPSS 20 to analyze the data. Results: Regression model showed Skin expansion was positively correlated with the volume of the injected fluid. For each centimeter square of skin expansion, about 6-8 ml of fluid must be injected. Conclusion: Correction of skin defects resulting from burning scar is possible using tissue expanders. The tissue expansion is correlated with the amount of the injected fluid.

Bioprinted Osteogenic and Vasculogenic Patterns for Engineering 3D Bone Tissue.

Science.gov (United States)

Byambaa, Batzaya; Annabi, Nasim; Yue, Kan; Trujillo-de Santiago, Grissel; Alvarez, Mario Moisés; Jia, Weitao; Kazemzadeh-Narbat, Mehdi; Shin, Su Ryon; Tamayol, Ali; Khademhosseini, Ali

2017-08-01

Fabricating 3D large-scale bone tissue constructs with functional vasculature has been a particular challenge in engineering tissues suitable for repairing large bone defects. To address this challenge, an extrusion-based direct-writing bioprinting strategy is utilized to fabricate microstructured bone-like tissue constructs containing a perfusable vascular lumen. The bioprinted constructs are used as biomimetic in vitro matrices to co-culture human umbilical vein endothelial cells and bone marrow derived human mesenchymal stem cells in a naturally derived hydrogel. To form the perfusable blood vessel inside the bioprinted construct, a central cylinder with 5% gelatin methacryloyl (GelMA) hydrogel at low methacryloyl substitution (GelMA LOW ) was printed. We also develop cell-laden cylinder elements made of GelMA hydrogel loaded with silicate nanoplatelets to induce osteogenesis, and synthesized hydrogel formulations with chemically conjugated vascular endothelial growth factor to promote vascular spreading. It was found that the engineered construct is able to support cell survival and proliferation during maturation in vitro. Additionally, the whole construct demonstrates high structural stability during the in vitro culture for 21 days. This method enables the local control of physical and chemical microniches and the establishment of gradients in the bioprinted constructs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chitosan-Graphene Oxide 3D scaffolds as Promising Tools for Bone Regeneration in Critical-Size Mouse Calvarial Defects.

Science.gov (United States)

Hermenean, Anca; Codreanu, Ada; Herman, Hildegard; Balta, Cornel; Rosu, Marcel; Mihali, Ciprian Valentin; Ivan, Alexandra; Dinescu, Sorina; Ionita, Mariana; Costache, Marieta

2017-11-30

Limited self-regenerating capacity of human skeleton makes the reconstruction of critical size bone defect a significant challenge for clinical practice. Aimed for regenerating bone tissues, this study was designed to investigate osteogenic differentiation, along with bone repair capacity of 3D chitosan (CHT) scaffolds enriched with graphene oxide (GO) in critical-sized mouse calvarial defect. Histopathological/histomorphometry and scanning electron microscopy(SEM) analysis of the implants revealed larger amount of new bone in the CHT/GO-filled defects compared with CHT alone (p < 0.001). When combined with GO, CHT scaffolds synergistically promoted the increase of alkaline phosphatase activity both in vitro and in vivo experiments. This enhanced osteogenesis was corroborated with increased expression of bone morphogenetic protein (BMP) and Runx-2 up to week 4 post-implantation, which showed that GO facilitates the differentiation of osteoprogenitor cells. Meanwhile, osteogenesis was promoted by GO at the late stage as well, as indicated by the up-regulation of osteopontin and osteocalcin at week 8 and overexpressed at week 18, for both markers. Our data suggest that CHT/GO biomaterial could represent a promising tool for the reconstruction of large bone defects, without using exogenous living cells or growth factors.

Semi-supervised rail defect detection from imbalanced image data

NARCIS (Netherlands)

Hajizadeh, S.; Nunez Vicencio, Alfredo; Tax, D.M.J.; Acarman, Tankut

2016-01-01

Rail defect detection by video cameras has recently gained much attention in both
academia and industry. Rail image data has two properties. It is highly imbalanced towards the non-defective class and it has a large number of unlabeled data samples available for semisupervised learning

A Mineralized Collagen-Polycaprolactone Composite Promotes Healing of a Porcine Mandibular Defect.

Science.gov (United States)

Weisgerber, Daniel W; Milner, Derek J; Lopez-Lake, Heather; Rubessa, Marcello; Lotti, Sammi; Polkoff, Kathryn; Hortensius, Rebecca A; Flanagan, Colleen L; Hollister, Scott J; Wheeler, Matthew B; Harley, Brendan A C

2018-02-01

A tissue engineering approach to address craniofacial defects requires a biomaterial that balances macro-scale mechanical stiffness and strength with the micron-scale features that promote cell expansion and tissue biosynthesis. Such criteria are often in opposition, leading to suboptimal mechanical competence or bioactivity. We report the use of a multiscale composite biomaterial that integrates a polycaprolactone (PCL) reinforcement structure with a mineralized collagen-glycosaminoglycan scaffold to circumvent conventional tradeoffs between mechanics and bioactivity. The composite promotes activation of the canonical bone morphogenetic protein 2 (BMP-2) pathway and subsequent mineralization of adipose-derived stem cells in the absence of supplemental BMP-2 or osteogenic media. We subsequently examined new bone infill in the acellular composite, scaffold alone, or PCL support in 10 mm dia. ramus mandibular defects in Yorkshire pigs. We report an analytical approach to quantify radial, angular, and depth bone infill from micro-computed tomography data. The collagen-PCL composite showed improved overall infill, and significantly increased radial and angular bone infill versus the PCL cage alone. Bone infill was further enhanced in the composite for defects that penetrated the medullary cavity, suggesting recruitment of marrow-derived cells. These results indicate a multiscale mineralized collagen-PCL composite offers strategic advantages for regenerative repair of craniofacial bone defects.

Fracture of vacancy-defected carbon nanotubes and their embedded nanocomposites

International Nuclear Information System (INIS)

Xiao Shaoping; Hou Wenyi

2006-01-01

In this paper, we investigate effects of vacancy defects on fracture of carbon nanotubes and carbon nanotube/aluminum composites. Our studies show that even a one-atom vacancy defect can dramatically reduce the failure stresses and strains of carbon nanotubes. Consequently, nanocomposites, in which vacancy-defected nanotubes are embedded, exhibit different characteristics from those in which pristine nanotubes are embedded. It has been found that defected nanotubes with a small volume fraction cannot reinforce but instead weaken nanocomposite materials. Although a large volume fraction of defected nanotubes can slightly increase the failure stresses of nanocomposites, the failure strains of nanocomposites are always decreased

Effect of dose and size on defect engineering in carbon cluster implanted silicon wafers

Science.gov (United States)

Okuyama, Ryosuke; Masada, Ayumi; Shigematsu, Satoshi; Kadono, Takeshi; Hirose, Ryo; Koga, Yoshihiro; Okuda, Hidehiko; Kurita, Kazunari

2018-01-01

Carbon-cluster-ion-implanted defects were investigated by high-resolution cross-sectional transmission electron microscopy toward achieving high-performance CMOS image sensors. We revealed that implantation damage formation in the silicon wafer bulk significantly differs between carbon-cluster and monomer ions after implantation. After epitaxial growth, small and large defects were observed in the implanted region of carbon clusters. The electron diffraction pattern of both small and large defects exhibits that from bulk crystalline silicon in the implanted region. On the one hand, we assumed that the silicon carbide structure was not formed in the implanted region, and small defects formed because of the complex of carbon and interstitial silicon. On the other hand, large defects were hypothesized to originate from the recrystallization of the amorphous layer formed by high-dose carbon-cluster implantation. These defects are considered to contribute to the powerful gettering capability required for high-performance CMOS image sensors.

Development of tissue bank

Directory of Open Access Journals (Sweden)

R P Narayan

2012-01-01

Full Text Available The history of tissue banking is as old as the use of skin grafting for resurfacing of burn wounds. Beneficial effects of tissue grafts led to wide spread use of auto and allograft for management of varied clinical conditions like skin wounds, bone defects following trauma or tumor ablation. Availability of adequate amount of tissues at the time of requirement was the biggest challenge that forced clinicians to find out techniques to preserve the living tissue for prolonged period of time for later use and thus the foundation of tissue banking was started in early twentieth century. Harvesting, processing, storage and transportation of human tissues for clinical use is the major activity of tissue banks. Low temperature storage of processed tissue is the best preservation technique at present. Tissue banking organization is a very complex system and needs high technical expertise and skilled personnel for proper functioning in a dedicated facility. A small lapse/deviation from the established protocol leads to loss of precious tissues and or harm to recipients as well as the risk of transmission of deadly diseases and tumors. Strict tissue transplant acts and stringent regulations help to streamline the whole process of tissue banking safe for recipients and to community as whole.

Use of NASA Bioreactor in Engineering Tissue for Bone Repair

Science.gov (United States)

Duke, Pauline

1998-01-01

This study was proposed in search for a new alternative for bone replacement or repair. Because the systems commonly used in repair of bony defects form bone by going through a cartilaginous phase, implantation of a piece of cartilage could enhance the healing process by having a more advanced starting point. However, cartilage has seldom been used to replace bone due, in part, to the limitations in conventional culture systems that did not allow production of enough tissue for implants. The NASA-developed bioreactors known as STLV (Slow Turning Lateral Vessel) provide homogeneous distribution of cells, nutrients, and waste products, with less damaging turbulence and shear forces than conventional systems. Cultures under these conditions have higher growth rates, viability, and longevity, allowing larger "tissue-like" aggregates to form, thus opening the possibilities of producing enough tissue for implantation, along with the inherent advantages of in vitro manipulations. To assure large numbers of cells and to eliminate the use of timed embryos, we proposed to use an immortalized mouse limb bud cell line as the source of cells.

Adipose-derived stem cells and BMP-2 delivery in chitosan-based 3D constructs to enhance bone regeneration in a rat mandibular defect model.

Science.gov (United States)

Fan, Jiabing; Park, Hyejin; Lee, Matthew K; Bezouglaia, Olga; Fartash, Armita; Kim, Jinku; Aghaloo, Tara; Lee, Min

2014-08-01

Reconstructing segmental mandiblular defects remains a challenge in the clinic. Tissue engineering strategies provide an alternative option to resolve this problem. The objective of the present study was to determine the effects of adipose-derived stem cells (ASCs) and bone morphogenetic proteins-2 (BMP-2) in three-dimensional (3D) scaffolds on mandibular repair in a small animal model. Noggin expression levels in ASCs were downregulated by a lentiviral short hairpin RNA strategy to enhance ASC osteogenesis (ASCs(Nog-)). Chitosan (CH) and chondroitin sulfate (CS), natural polysaccharides, were fabricated into 3D porous scaffolds, which were further modified with apatite coatings for enhanced cellular responses and efficient delivery of BMP-2. The efficacy of 3D apatite-coated CH/CS scaffolds supplemented with ASCs(Nog-) and BMP-2 were evaluated in a rat critical-sized mandibular defect model. After 8 weeks postimplantation, the scaffolds treated with ASCs(Nog-) and BMP-2 significantly promoted rat mandibular regeneration as demonstrated by micro-computerized tomography, histology, and immunohistochemistry, compared with the groups treated with ASCs(Nog-) or BMP-2 alone. These results suggest that our combinatorial strategy of ASCs(Nog-)+BMP-2 in 3D apatite microenvironments can significantly promote mandibular regeneration, and these may provide a potential tissue engineering approach to repair large bony defects.

Large cerebral perfusion defects observed in brain perfusion SPECT may herald psychiatric or neurodegenerative diseases of transient global amnesia patients

Energy Technology Data Exchange (ETDEWEB)

So, Young; Kim, Hahn Young; Roh, Hong Gee; Han, Seol Heui [Konkuk University School of Medicine, Seoul (Korea, Republic of)

2007-07-01

Transient global amnesia (TGA) is a memory disorder characterized by an episode of antegrade amnesia and bewilderment which persists for several hours. We analyzed brain perfusion SPECT findings and clinical outcome of patients who suffered from TGA. From September 2005 to August 2007, 12 patients underwent Tc-99m ECD brain perfusion SPECT for neuroimaging of TGA. All patients also underwent MRI and MRA including DWI (MRI). Among them, 10 patients who could be chased more than 6 months were included in this study. Their average age was 60.74.0 yrs (M: F = 2: 8) and the average duration of amnesia was 4.42.2 hrs (1 hr {approx} 7 hrs). Duration from episode of amnesia to SPECT was 4.32.4 days (1{approx}9 days). Precipitating factors could be identified in 6 patients: emotional stress 3, hair dyeing 1, taking a nap 1 and angioplasty 1. SPECT and MRI was visually assessed, No cerebral perfusion defect was observed on SPECT in 3 patients and their clinical outcome was all good. Among 7 patients who had cerebral perfusion defects on SPECT, 3 patients had good clinical outcome, while others did not: one had hypercholesterolemia, another had depression, and 2 patients with cerebral perfusion defects at both temporoparetal cortex was later diagnosed as early Alzheimer's disease (AD) and mild cognitive impairment (MCI). MRI was negative in 6 patients and 3 of them had excellent clinical outcome while other 3 were diagnosed as hypercholesterolemia, early AD and MCI. Among 4 patients with positive MRI, 3 showed good clinical outcome and their MRI showed lesions at medial temporal cortex and/or vertebral artery. One patient with microcalcification at left putamen was diagnosed to have depression. Large cerebral perfusion defects on SPECT may herald psychiatric or neurodegenerative diseases of transient global amnesia patients which usually shows negative MRI.

Large cerebral perfusion defects observed in brain perfusion SPECT may herald psychiatric or neurodegenerative diseases of transient global amnesia patients

International Nuclear Information System (INIS)

So, Young; Kim, Hahn Young; Roh, Hong Gee; Han, Seol Heui

2007-01-01

Transient global amnesia (TGA) is a memory disorder characterized by an episode of antegrade amnesia and bewilderment which persists for several hours. We analyzed brain perfusion SPECT findings and clinical outcome of patients who suffered from TGA. From September 2005 to August 2007, 12 patients underwent Tc-99m ECD brain perfusion SPECT for neuroimaging of TGA. All patients also underwent MRI and MRA including DWI (MRI). Among them, 10 patients who could be chased more than 6 months were included in this study. Their average age was 60.74.0 yrs (M: F = 2: 8) and the average duration of amnesia was 4.42.2 hrs (1 hr ∼ 7 hrs). Duration from episode of amnesia to SPECT was 4.32.4 days (1∼9 days). Precipitating factors could be identified in 6 patients: emotional stress 3, hair dyeing 1, taking a nap 1 and angioplasty 1. SPECT and MRI was visually assessed, No cerebral perfusion defect was observed on SPECT in 3 patients and their clinical outcome was all good. Among 7 patients who had cerebral perfusion defects on SPECT, 3 patients had good clinical outcome, while others did not: one had hypercholesterolemia, another had depression, and 2 patients with cerebral perfusion defects at both temporoparetal cortex was later diagnosed as early Alzheimer's disease (AD) and mild cognitive impairment (MCI). MRI was negative in 6 patients and 3 of them had excellent clinical outcome while other 3 were diagnosed as hypercholesterolemia, early AD and MCI. Among 4 patients with positive MRI, 3 showed good clinical outcome and their MRI showed lesions at medial temporal cortex and/or vertebral artery. One patient with microcalcification at left putamen was diagnosed to have depression. Large cerebral perfusion defects on SPECT may herald psychiatric or neurodegenerative diseases of transient global amnesia patients which usually shows negative MRI

Recent advances in hydrogels for cartilage tissue engineering

Directory of Open Access Journals (Sweden)

SL Vega

2017-01-01

Full Text Available Articular cartilage is a load-bearing tissue that lines the surface of bones in diarthrodial joints. Unfortunately, this avascular tissue has a limited capacity for intrinsic repair. Treatment options for articular cartilage defects include microfracture and arthroplasty; however, these strategies fail to generate tissue that adequately restores damaged cartilage. Limitations of current treatments for cartilage defects have prompted the field of cartilage tissue engineering, which seeks to integrate engineering and biological principles to promote the growth of new cartilage to replace damaged tissue. To date, a wide range of scaffolds and cell sources have emerged with a focus on recapitulating the microenvironments present during development or in adult tissue, in order to induce the formation of cartilaginous constructs with biochemical and mechanical properties of native tissue. Hydrogels have emerged as a promising scaffold due to the wide range of possible properties and the ability to entrap cells within the material. Towards improving cartilage repair, hydrogel design has advanced in recent years to improve their utility. Some of these advances include the development of improved network crosslinking (e.g. double-networks, new techniques to process hydrogels (e.g. 3D printing and better incorporation of biological signals (e.g. controlled release. This review summarises these innovative approaches to engineer hydrogels towards cartilage repair, with an eye towards eventual clinical translation.

Recent advances in hydrogels for cartilage tissue engineering.

Science.gov (United States)

Vega, S L; Kwon, M Y; Burdick, J A

2017-01-30

Articular cartilage is a load-bearing tissue that lines the surface of bones in diarthrodial joints. Unfortunately, this avascular tissue has a limited capacity for intrinsic repair. Treatment options for articular cartilage defects include microfracture and arthroplasty; however, these strategies fail to generate tissue that adequately restores damaged cartilage. Limitations of current treatments for cartilage defects have prompted the field of cartilage tissue engineering, which seeks to integrate engineering and biological principles to promote the growth of new cartilage to replace damaged tissue. To date, a wide range of scaffolds and cell sources have emerged with a focus on recapitulating the microenvironments present during development or in adult tissue, in order to induce the formation of cartilaginous constructs with biochemical and mechanical properties of native tissue. Hydrogels have emerged as a promising scaffold due to the wide range of possible properties and the ability to entrap cells within the material. Towards improving cartilage repair, hydrogel design has advanced in recent years to improve their utility. Some of these advances include the development of improved network crosslinking (e.g. double-networks), new techniques to process hydrogels (e.g. 3D printing) and better incorporation of biological signals (e.g. controlled release). This review summarises these innovative approaches to engineer hydrogels towards cartilage repair, with an eye towards eventual clinical translation.

Bioactive glass and glass-ceramic scaffolds for bone tissue engineering

NARCIS (Netherlands)

Gerhardt, L.C.; Boccaccini, A.R.

2010-01-01

Traditionally, bioactive glasses have been used to fill and restore bone defects. More recently, this category of biomaterials has become an emerging research field for bone tissue engineering applications. Here, we review and discuss current knowledge on porous bone tissue engineering scaffolds on

Stochastic annealing simulations of defect interactions among subcascades

Energy Technology Data Exchange (ETDEWEB)

Heinisch, H.L. [Pacific Northwest National Lab., Richland, WA (United States); Singh, B.N.

1997-04-01

The effects of the subcascade structure of high energy cascades on the temperature dependencies of annihilation, clustering and free defect production are investigated. The subcascade structure is simulated by closely spaced groups of lower energy MD cascades. The simulation results illustrate the strong influence of the defect configuration existing in the primary damage state on subsequent intracascade evolution. Other significant factors affecting the evolution of the defect distribution are the large differences in mobility and stability of vacancy and interstitial defects and the rapid one-dimensional diffusion of small, glissile interstitial loops produced directly in cascades. Annealing simulations are also performed on high-energy, subcascade-producing cascades generated with the binary collision approximation and calibrated to MD results.

Surgical-prosthetic treatment of large mandibular cysts

Directory of Open Access Journals (Sweden)

Džambas Ljubiša D.

2003-01-01

Full Text Available This paper presents a combined surgical-prosthetic procedure of reconstructing mandibular bone defect in a 53 year old patient, following enucleation of a mandibular cyst (Cystectomy Partsch II. After a thorough diagnostic evaluation, a surgical procedure was planned with the particular attention to the nature of the disease, patient’s condition, size and extension of the cyst, tissue loss, and the possibilities of prosthetic management of a mandibular bone defect with partial postresection dental prosthesis. It is of great importance to point to the significance of teamwork of a maxillofacial surgeon and a specialist in prosthodontics. This kind of cooperation provided very effective and less risky soft tissue, as well as bone tissue regeneration (osteogenesis. The patient’s recovery was fast, and he could return to his daily activities and work without significant changes regarding quality of life after surgery and prosthetic treatment.

Design Approaches to Myocardial and Vascular Tissue Engineering.

Science.gov (United States)

Akintewe, Olukemi O; Roberts, Erin G; Rim, Nae-Gyune; Ferguson, Michael A H; Wong, Joyce Y

2017-06-21

Engineered tissues represent an increasingly promising therapeutic approach for correcting structural defects and promoting tissue regeneration in cardiovascular diseases. One of the challenges associated with this approach has been the necessity for the replacement tissue to promote sufficient vascularization to maintain functionality after implantation. This review highlights a number of promising prevascularization design approaches for introducing vasculature into engineered tissues. Although we focus on encouraging blood vessel formation within myocardial implants, we also discuss techniques developed for other tissues that could eventually become relevant to engineered cardiac tissues. Because the ultimate solution to engineered tissue vascularization will require collaboration between wide-ranging disciplines such as developmental biology, tissue engineering, and computational modeling, we explore contributions from each field.

Defective Wound-healing in Aging Gingival Tissue.

Science.gov (United States)

Cáceres, M; Oyarzun, A; Smith, P C

2014-07-01

Aging may negatively affect gingival wound-healing. However, little is known about the mechanisms underlying this phenomenon. The present study examined the cellular responses associated with gingival wound-healing in aging. Primary cultures of human gingival fibroblasts were obtained from healthy young and aged donors for the analysis of cell proliferation, cell invasion, myofibroblastic differentiation, and collagen gel remodeling. Serum from young and old rats was used to stimulate cell migration. Gingival repair was evaluated in Sprague-Dawley rats of different ages. Data were analyzed by the Mann-Whitney and Kruskal-Wallis tests, with a p value of .05. Fibroblasts from aged donors showed a significant decrease in cell proliferation, migration, Rac activation, and collagen remodeling when compared with young fibroblasts. Serum from young rats induced higher cell migration when compared with serum from old rats. After TGF-beta1 stimulation, both young and old fibroblasts demonstrated increased levels of alpha-SMA. However, alpha-SMA was incorporated into actin stress fibers in young but not in old fibroblasts. After 7 days of repair, a significant delay in gingival wound-healing was observed in old rats. The present study suggests that cell migration, myofibroblastic differentiation, collagen gel remodeling, and proliferation are decreased in aged fibroblasts. In addition, altered cell migration in wound-healing may be attributable not only to cellular defects but also to changes in serum factors associated with the senescence process. © International & American Associations for Dental Research.

Glabrous skin reconstruction of palmar/plantar defects: a case for the ...

African Journals Online (AJOL)

DR LEGBO

Methods: A prospective descriptive study of consecutive patients with benign soft tissue palmar/plantar defects .... cannot be closed by direct suturing. In the authors' view ... splintage ) did not lead to joint stiffness since majority were children ...

Vascular and micro-environmental influences on MSC-coral hydroxyapatite construct-based bone tissue engineering.

Science.gov (United States)

Cai, Lei; Wang, Qian; Gu, Congmin; Wu, Jingguo; Wang, Jian; Kang, Ning; Hu, Jiewei; Xie, Fang; Yan, Li; Liu, Xia; Cao, Yilin; Xiao, Ran

2011-11-01

Bone tissue engineering (BTE) has been demonstrated an effective approach to generate bone tissue and repair bone defect in ectopic and orthotopic sites. The strategy of using a prevascularized tissue-engineered bone grafts (TEBG) fabricated ectopically to repair bone defects, which is called live bone graft surgery, has not been reported. And the quantitative advantages of vascularization and osteogenic environment in promoting engineered bone formation have not been defined yet. In the current study we generated a tissue engineered bone flap with a vascular pedicle of saphenous arteriovenous in which an organized vascular network was observed after 4 weeks implantation, and followed by a successful repaire of fibular defect in beagle dogs. Besides, after a 9 months long term observation of engineered bone formation in ectopic and orthotopic sites, four CHA (coral hydroxyapatite) scaffold groups were evaluated by CT (computed tomography) analysis. By the comparison of bone formation and scaffold degradation between different groups, the influences of vascularization and micro-environment on tissue engineered bone were quantitatively analyzed. The results showed that in the first 3 months vascularization improved engineered bone formation by 2 times of non-vascular group and bone defect micro-environment improved it by 3 times of ectopic group, and the CHA-scaffold degradation was accelerated as well. Copyright © 2011 Elsevier Ltd. All rights reserved.

The effects of odontogenic and nonodontogenic tissues on bone healing in Guinea pig mandible

International Nuclear Information System (INIS)

Kim, So Jung; Hwang, Eui Hwan; Lee, Sang Rae; Hong, Jung Pyo

1996-01-01

This study was for comparing healing patterns and effects between with odontogenic and nonodontogenic tissues on the defected mandible. Experimental bone defects that measured 3 mm in diameter were created on the mandibular body of guinea pig by removal of bone with the use of trephine burs and bone defects were grafted with Biogran (Orthovita Co., U.S. A.) and covered with Dura Mata (Pfrimmer-Viggo GmbH Co., Germany). Guinea pigs were serially terminated by fours on the 3 days, the 1 week, the 2 weeks, the 3 weeks, the 4 weeks, and the 5 weeks after experiment, and the mandibular body was removed and fixed with 10% neutral formalin. They were decalcified and embedded in paraffin as using the usual methods. The specimen sectioned and stained with hematoxylin and eosin and toluidine blue. They were observed with a light microscope and a polarizing microscope. The obtained results were as follows: 1. Defected bone was healed fast from the odontogenic tissues in early stage of the experiment. 2. The arrangement of the bone matrix was relatively regular in the bone from the nonodontogenic tissues, but irregular in the bone from the odotogenic tissues. 3. Compact bone has started to be absorbed and changed to the pattern of matrix bone tissue from 3 weeks after experiment.

A new fundamental hydrogen defect in alkali halides

International Nuclear Information System (INIS)

Morato, S.P.; Luety, F.

1978-01-01

Atom hydrogen in neutral (H 0 ) and negative (H - ) form on substitutional and interstitial lattice sites gives rise to well characterized model defects in alkali-halides (U,U 1 ,U 2 ,U 3 centers), which have been extensively investigated in the past. When studying the photo-decomposition of OH - defects, a new configuration of atomic charged hidrogen was discovered, which can be produced in large quantities in the crystal and is apparently not connected to any other impurity. This new hidrogen defect does not show any pronounced electronic absorption, but displays a single sharp local mode band (at 1114cm -1 in KCl) with a perfect isotope shift. The defect can be produced by various UV or X-ray techniques in crystais doped with OH - , Sh - or H - defects. A detailed study of its formation kinetics at low temperature shows that it is primarily formed by the reaction of a mobile CI 2 - crowdion (H-center) with hidrogen defects [pt

Introduction to regenerative medicine and tissue engineering.

Science.gov (United States)

Stoltz, J-F; Decot, V; Huseltein, C; He, X; Zhang, L; Magdalou, J; Li, Y P; Menu, P; Li, N; Wang, Y Y; de Isla, N; Bensoussan, D

2012-01-01

Human tissues don't regenerate spontaneously, explaining why regenerative medicine and cell therapy represent a promising alternative treatment (autologous cells or stem cells of different origins). The principle is simple: cells are collected, expanded and introduced with or without modification into injured tissues or organs. Among middle-term therapeutic applications, cartilage defects, bone repair, cardiac insufficiency, burns, liver or bladder, neurodegenerative disorders could be considered.

Enzyme replacement prevents enamel defects in hypophosphatasia mice

Science.gov (United States)

Yadav, Manisha C.; de Oliveira, Rodrigo Cardoso; Foster, Brian L.; Fong, Hanson; Cory, Esther; Narisawa, Sonoko; Sah, Robert L.; Somerman, Martha; Whyte, Michael P.; Millán, José Luis

2012-01-01

Hypophosphatasia (HPP) is the inborn error of metabolism characterized by deficiency of alkaline phosphatase activity leading to rickets or osteomalacia and to dental defects. HPP occurs from loss-of-function mutations within the gene that encodes the tissue-nonspecific isozyme of alkaline phosphatase (TNAP). TNAP knockout (Alpl−/−, a.k.a. Akp2−/−) mice closely phenocopy infantile HPP, including the rickets, vitamin B6-responsive seizures, improper dentin mineralization, and lack of acellular cementum. Here, we report that lack of TNAP in Alpl−/− mice also causes severe enamel defects, which are preventable by enzyme replacement with mineral-targeted TNAP (ENB-0040). Immunohistochemistry was used to map the spatiotemporal expression of TNAP in the tissues of the developing enamel organ of healthy mouse molars and incisors. We found strong, stage-specific expression of TNAP in ameloblasts. In the Alpl−/− mice, histological, μCT, and scanning electron microscopy analysis showed reduced mineralization and disrupted organization of the rods and inter-rod structures in enamel of both the molars and incisors. All of these abnormalities were prevented in mice receiving from birth daily subcutaneous injections of mineral-targeting, human TNAP (sALP-FcD10, a.k.a. ENB-0040) at 8.2 mg/kg/day for up to 44 days. These data reveal an important role for TNAP in enamel mineralization, and demonstrate the efficacy of mineral-targeted TNAP to prevent enamel defects in HPP. PMID:22461224

Osteochondral defect repair using a polyvinyl alcohol-polyacrylic acid (PVA-PAAc) hydrogel.

Science.gov (United States)

Bichara, David A; Bodugoz-Sentruk, Hatice; Ling, Doris; Malchau, Erik; Bragdon, Charles R; Muratoglu, Orhun K

2014-08-01

Poly(vinyl alcohol) (PVA) hydrogels can be candidates for articular cartilage repair due to their high water content. We synthesized a PVA-poly(acrylic acid) (PAAc) hydrogel formulation and determined its ability to function as a treatment option for condylar osteochondral (OC) defects in a New Zealand white rabbit (NZWR) model for 12 weeks and 24 weeks. In addition to hydrogel OC implants, tensile bar-shaped hydrogels were also implanted subcutaneously to evaluate changes in mechanical properties as a function of in vivo duration. There were no statistically significant differences (p > 0.05) in the water content measured in the OC hydrogel implant that was harvested after 12 weeks and 24 weeks, and non-implanted controls. There were no statistically significant differences (p > 0.05) in the break stress, strain at break or modulus of the tensile bars either between groups. Histological analysis of the OC defect, synovial capsule and fibrous tissue around the tensile bars determined hydrogel biocompatibility. Twelve-week hydrogels were found to be in situ flush with the articular cartilage; meniscal tissue demonstrated an intact surface. Twenty-four week hydrogels protruded from the defect site due to lack of integration with subchondral tissue, causing fibrillation to the meniscal surface. Condylar micro-CT scans ruled out osteolysis and bone cysts of the subchondral bone, and no PVA-PAAc hydrogel contents were found in the synovial fluid. The PVA-PAAc hydrogel was determined to be fully biocompatible, maintained its properties over time, and performed well at the 12 week time point. Physical fixation of the PVA-PAAc hydrogel to the subchondral bone is required to ensure long-term performance of hydrogel plugs for OC defect repair.

Influence of radiation induced defect clusters on silicon particle detectors

International Nuclear Information System (INIS)

Junkes, Alexandra

2011-10-01

The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) addresses some of today's most fundamental questions of particle physics, like the existence of the Higgs boson and supersymmetry. Two large general-purpose experiments (ATLAS, CMS) are installed to detect the products of high energy protonproton and nucleon-nucleon collisions. Silicon detectors are largely employed in the innermost region, the tracking area of the experiments. The proven technology and large scale availability make them the favorite choice. Within the framework of the LHC upgrade to the high-luminosity LHC, the luminosity will be increased to L=10 35 cm -2 s -1 . In particular the pixel sensors in the innermost layers of the silicon trackers will be exposed to an extremely intense radiation field of mainly hadronic particles with fluences of up to Φ eq =10 16 cm -2 . The radiation induced bulk damage in silicon sensors will lead to a severe degradation of the performance during their operational time. This work focusses on the improvement of the radiation tolerance of silicon materials (Float Zone, Magnetic Czochralski, epitaxial silicon) based on the evaluation of radiation induced defects in the silicon lattice using the Deep Level Transient Spectroscopy and the Thermally Stimulated Current methods. It reveals the outstanding role of extended defects (clusters) on the degradation of sensor properties after hadron irradiation in contrast to previous works that treated effects as caused by point defects. It has been found that two cluster related defects are responsible for the main generation of leakage current, the E5 defects with a level in the band gap at E C -0.460 eV and E205a at E C -0.395 eV where E C is the energy of the edge of the conduction band. The E5 defect can be assigned to the tri-vacancy (V 3 ) defect. Furthermore, isochronal annealing experiments have shown that the V 3 defect exhibits a bistability, as does the leakage current. In oxygen

Influence of radiation induced defect clusters on silicon particle detectors

Energy Technology Data Exchange (ETDEWEB)

Junkes, Alexandra

2011-10-15

The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) addresses some of today's most fundamental questions of particle physics, like the existence of the Higgs boson and supersymmetry. Two large general-purpose experiments (ATLAS, CMS) are installed to detect the products of high energy protonproton and nucleon-nucleon collisions. Silicon detectors are largely employed in the innermost region, the tracking area of the experiments. The proven technology and large scale availability make them the favorite choice. Within the framework of the LHC upgrade to the high-luminosity LHC, the luminosity will be increased to L=10{sup 35} cm{sup -2}s{sup -1}. In particular the pixel sensors in the innermost layers of the silicon trackers will be exposed to an extremely intense radiation field of mainly hadronic particles with fluences of up to {phi}{sub eq}=10{sup 16} cm{sup -2}. The radiation induced bulk damage in silicon sensors will lead to a severe degradation of the performance during their operational time. This work focusses on the improvement of the radiation tolerance of silicon materials (Float Zone, Magnetic Czochralski, epitaxial silicon) based on the evaluation of radiation induced defects in the silicon lattice using the Deep Level Transient Spectroscopy and the Thermally Stimulated Current methods. It reveals the outstanding role of extended defects (clusters) on the degradation of sensor properties after hadron irradiation in contrast to previous works that treated effects as caused by point defects. It has been found that two cluster related defects are responsible for the main generation of leakage current, the E5 defects with a level in the band gap at E{sub C}-0.460 eV and E205a at E{sub C}-0.395 eV where E{sub C} is the energy of the edge of the conduction band. The E5 defect can be assigned to the tri-vacancy (V{sub 3}) defect. Furthermore, isochronal annealing experiments have shown that the V{sub 3} defect

The essence of biophysical cues in skeletal muscle tissue engineering

NARCIS (Netherlands)

Langelaan, M.L.P.

2010-01-01

Skeletal muscle is an appealing topic for tissue engineering because of its variety in applications. Evidently, tissue engineered skeletal muscle can be used in the field of regenerative medicine to repair muscular defects or dystrophies. Engineered skeletal muscle constructs can also be used as a

Current strategies in multiphasic scaffold design for osteochondral tissue engineering: A review.

Science.gov (United States)

Yousefi, Azizeh-Mitra; Hoque, Md Enamul; Prasad, Rangabhatala G S V; Uth, Nicholas

2015-07-01

The repair of osteochondral defects requires a tissue engineering approach that aims at mimicking the physiological properties and structure of two different tissues (cartilage and bone) using specifically designed scaffold-cell constructs. Biphasic and triphasic approaches utilize two or three different architectures, materials, or composites to produce a multilayered construct. This article gives an overview of some of the current strategies in multiphasic/gradient-based scaffold architectures and compositions for tissue engineering of osteochondral defects. In addition, the application of finite element analysis (FEA) in scaffold design and simulation of in vitro and in vivo cell growth outcomes has been briefly covered. FEA-based approaches can potentially be coupled with computer-assisted fabrication systems for controlled deposition and additive manufacturing of the simulated patterns. Finally, a summary of the existing challenges associated with the repair of osteochondral defects as well as some recommendations for future directions have been brought up in the concluding section of this article. © 2014 Wiley Periodicals, Inc.

Polydispersity-driven topological defects as order-restoring excitations.

Science.gov (United States)

Yao, Zhenwei; Olvera de la Cruz, Monica

2014-04-08

The engineering of defects in crystalline matter has been extensively exploited to modify the mechanical and electrical properties of many materials. Recent experiments on manipulating extended defects in graphene, for example, show that defects direct the flow of electric charges. The fascinating possibilities offered by defects in two dimensions, known as topological defects, to control material properties provide great motivation to perform fundamental investigations to uncover their role in various systems. Previous studies mostly focus on topological defects in 2D crystals on curved surfaces. On flat geometries, topological defects can be introduced via density inhomogeneities. We investigate here topological defects due to size polydispersity on flat surfaces. Size polydispersity is usually an inevitable feature of a large variety of systems. In this work, simulations show well-organized induced topological defects around an impurity particle of a wrong size. These patterns are not found in systems of identical particles. Our work demonstrates that in polydispersed systems topological defects play the role of restoring order. The simulations show a perfect hexagonal lattice beyond a small defective region around the impurity particle. Elasticity theory has demonstrated an analogy between the elementary topological defects named disclinations to electric charges by associating a charge to a disclination, whose sign depends on the number of its nearest neighbors. Size polydispersity is shown numerically here to be an essential ingredient to understand short-range attractions between like-charge disclinations. Our study suggests that size polydispersity has a promising potential to engineer defects in various systems including nanoparticles and colloidal crystals.

Risk factors for pedicled flap necrosis in hand soft tissue reconstruction: a multivariate logistic regression analysis.

Science.gov (United States)

Gong, Xu; Cui, Jianli; Jiang, Ziping; Lu, Laijin; Li, Xiucun

2018-03-01

Few clinical retrospective studies have reported the risk factors of pedicled flap necrosis in hand soft tissue reconstruction. The aim of this study was to identify non-technical risk factors associated with pedicled flap perioperative necrosis in hand soft tissue reconstruction via a multivariate logistic regression analysis. For patients with hand soft tissue reconstruction, we carefully reviewed hospital records and identified 163 patients who met the inclusion criteria. The characteristics of these patients, flap transfer procedures and postoperative complications were recorded. Eleven predictors were identified. The correlations between pedicled flap necrosis and risk factors were analysed using a logistic regression model. Of 163 skin flaps, 125 flaps survived completely without any complications. The pedicled flap necrosis rate in hands was 11.04%, which included partial flap necrosis (7.36%) and total flap necrosis (3.68%). Soft tissue defects in fingers were noted in 68.10% of all cases. The logistic regression analysis indicated that the soft tissue defect site (P = 0.046, odds ratio (OR) = 0.079, confidence interval (CI) (0.006, 0.959)), flap size (P = 0.020, OR = 1.024, CI (1.004, 1.045)) and postoperative wound infection (P < 0.001, OR = 17.407, CI (3.821, 79.303)) were statistically significant risk factors for pedicled flap necrosis of the hand. Soft tissue defect site, flap size and postoperative wound infection were risk factors associated with pedicled flap necrosis in hand soft tissue defect reconstruction. © 2017 Royal Australasian College of Surgeons.

Extracting software static defect models using data mining

Directory of Open Access Journals (Sweden)

Ahmed H. Yousef

2015-03-01

Full Text Available Large software projects are subject to quality risks of having defective modules that will cause failures during the software execution. Several software repositories contain source code of large projects that are composed of many modules. These software repositories include data for the software metrics of these modules and the defective state of each module. In this paper, a data mining approach is used to show the attributes that predict the defective state of software modules. Software solution architecture is proposed to convert the extracted knowledge into data mining models that can be integrated with the current software project metrics and bugs data in order to enhance the prediction. The results show better prediction capabilities when all the algorithms are combined using weighted votes. When only one individual algorithm is used, Naïve Bayes algorithm has the best results, then the Neural Network and the Decision Trees algorithms.

Radiological Assessment of Bioengineered Bone in a Muscle Flap for the Reconstruction of Critical-Size Mandibular Defect

Science.gov (United States)

Al-Fotawei, Randa; Ayoub, Ashraf F.; Heath, Neil; Naudi, Kurt B.; Tanner, K. Elizabeth; Dalby, Matthew J.; McMahon, Jeremy

2014-01-01

This study presents a comprehensive radiographic evaluation of bone regeneration within a pedicled muscle flap for the reconstruction of critical size mandibular defect. The surgical defect (20 mm×15 mm) was created in the mandible of ten experimental rabbits. The masseter muscle was adapted to fill the surgical defect, a combination of calcium sulphate/hydroxyapatite cement (CERAMENT™ |SPINE SUPPORT), BMP-7 and rabbit mesenchymal stromal cells (rMSCs) was injected inside the muscle tissue. Radiographic assessment was carried out on the day of surgery and at 4, 8, and 12 weeks postoperatively. At 12 weeks, the animals were sacrificed and cone beam computerized tomography (CBCT) scanning and micro-computed tomography (µ-CT) were carried out. Clinically, a clear layer of bone tissue was identified closely adherent to the border of the surgical defect. Sporadic radio-opaque areas within the surgical defect were detected radiographically. In comparison with the opposite non operated control side, the estimated quantitative scoring of the radio-opacity was 46.6% ±15, the mean volume of the radio-opaque areas was 63.4% ±20. Areas of a bone density higher than that of the mandibular bone (+35% ±25%) were detected at the borders of the surgical defect. The micro-CT analysis revealed thinner trabeculae of the regenerated bone with a more condensed trabecular pattern than the surrounding native bone. These findings suggest a rapid deposition rate of the mineralised tissue and an active remodelling process of the newly regenerated bone within the muscle flap. The novel surgical model of this study has potential clinical application; the assessment of bone regeneration using the presented radiolographic protocol is descriptive and comprehensive. The findings of this research confirm the remarkable potential of local muscle flaps as local bioreactors to induce bone formation for reconstruction of maxillofacial bony defects. PMID:25226170

Radiological assessment of bioengineered bone in a muscle flap for the reconstruction of critical-size mandibular defect.

Directory of Open Access Journals (Sweden)

Randa Al-Fotawei

Full Text Available This study presents a comprehensive radiographic evaluation of bone regeneration within a pedicled muscle flap for the reconstruction of critical size mandibular defect. The surgical defect (20 mm × 15 mm was created in the mandible of ten experimental rabbits. The masseter muscle was adapted to fill the surgical defect, a combination of calcium sulphate/hydroxyapatite cement (CERAMENT™ |SPINE SUPPORT, BMP-7 and rabbit mesenchymal stromal cells (rMSCs was injected inside the muscle tissue. Radiographic assessment was carried out on the day of surgery and at 4, 8, and 12 weeks postoperatively. At 12 weeks, the animals were sacrificed and cone beam computerized tomography (CBCT scanning and micro-computed tomography (µ-CT were carried out. Clinically, a clear layer of bone tissue was identified closely adherent to the border of the surgical defect. Sporadic radio-opaque areas within the surgical defect were detected radiographically. In comparison with the opposite non operated control side, the estimated quantitative scoring of the radio-opacity was 46.6% ± 15, the mean volume of the radio-opaque areas was 63.4% ± 20. Areas of a bone density higher than that of the mandibular bone (+35% ± 25% were detected at the borders of the surgical defect. The micro-CT analysis revealed thinner trabeculae of the regenerated bone with a more condensed trabecular pattern than the surrounding native bone. These findings suggest a rapid deposition rate of the mineralised tissue and an active remodelling process of the newly regenerated bone within the muscle flap. The novel surgical model of this study has potential clinical application; the assessment of bone regeneration using the presented radiolographic protocol is descriptive and comprehensive. The findings of this research confirm the remarkable potential of local muscle flaps as local bioreactors to induce bone formation for reconstruction of maxillofacial bony defects.

Induced Magnetic Moment in Defected Single-Walled Carbon Nanotubes

International Nuclear Information System (INIS)

Liu Hong

2006-01-01

The existence of a large induced magnetic moment in defect single-walled carbon nanotube(SWNT) is predicted using the Green's function method. Specific to this magnetic moment of defect SWNT is its magnitude which is several orders of magnitude larger than that of perfect SWNT. The induced magnetic moment also shows certain remarkable features. Therefore, we suggest that two pair-defect orientations in SWNT can be distinguished in experiment through the direction of the induced magnetic moment at some Specific energy points

MINIMALLY INVASIVE SINGLE FLAP APPROACH WITH CONNECTIVE TISSUE WALL FOR PERIODONTAL REGENERATION

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Kamen Kotsilkov

2017-09-01

Full Text Available INTRODUCTION: The destructive periodontal diseases are among the most prevalent in the human population. In some cases, bony defects are formed during the disease progression, thus sustaining deep periodontal pockets. The reconstruction of these defects is usually done with the classical techniques of bone substitutes placement and guided tissue regeneration. The clinical and histological data from the recent years, however, demonstrate the relatively low regenerative potential of these techniques. The contemporary approaches for periodontal regeneration rely on minimally invasive surgical protocols, aimed at complete tissue preservation in order to achieve and maintain primary closure and at stimulating the natural regenerative potential of the periodontal tissues. AIM: This presentation demonstrates the application of a new, minimally invasive, single flap surgical technique for periodontal regeneration in a clinical case with periodontitis and a residual deep intrabony defect. MATERIALS AND METHODS: A 37 years old patient presented with chronic generalised periodontitis. The initial therapy led to good control of the periodontal infection with a single residual deep periodontal pocket medially at 11 due to a deep intrabony defect. A single flap approach with an enamel matrix derivate application and a connective tissue wall technique were performed. The proper primary closure was obtained. RESULT: One month after surgery an initial mineralisation process in the defect was detected. At the third month, a complete clinical healing was observed. The radiographic control showed finished bone mineralisation and periodontal space recreation. CONCLUSION: In the limitation of the presented case, the minimally invasive surgical approach led to complete clinical healing and new bone formation, which could be proof for periodontal regeneration.

Subsurface thermal behaviour of tissue mimics embedded with large blood vessels during plasmonic photo-thermal therapy.

Science.gov (United States)

Paul, Anup; Narasimhan, Arunn; Das, Sarit K; Sengupta, Soujit; Pradeep, Thalappil

2016-11-01

The purpose of this study was to understand the subsurface thermal behaviour of a tissue phantom embedded with large blood vessels (LBVs) when exposed to near-infrared (NIR) radiation. The effect of the addition of nanoparticles to irradiated tissue on the thermal sink behaviour of LBVs was also studied. Experiments were performed on a tissue phantom embedded with a simulated blood vessel of 2.2 mm outer diameter (OD)/1.6 mm inner diameter (ID) with a blood flow rate of 10 mL/min. Type I collagen from bovine tendon and agar gel were used as tissue. Two different nanoparticles, gold mesoflowers (AuMS) and graphene nanostructures, were synthesised and characterised. Energy equations incorporating a laser source term based on multiple scattering theories were solved using finite element-based commercial software. The rise in temperature upon NIR irradiation was seen to vary according to the position of the blood vessel and presence of nanoparticles. While the maximum rise in temperature was about 10 °C for bare tissue, it was 19 °C for tissue embedded with gold nanostructures and 38 °C for graphene-embedded tissues. The axial temperature distribution predicted by computational simulation matched the experimental observations. A different subsurface temperature distribution has been obtained for different tissue vascular network models. The position of LBVs must be known in order to achieve optimal tissue necrosis. The simulation described here helps in predicting subsurface temperature distributions within tissues during plasmonic photo-thermal therapy so that the risks of damage and complications associated with in vivo experiments and therapy may be avoided.

Additive Effect of Plasma Rich in Growth Factors With Guided Tissue Regeneration in Treatment of Intrabony Defects in Patients With Chronic Periodontitis: A Split-Mouth Randomized Controlled Clinical Trial.

Science.gov (United States)

Ravi, Sheethalan; Malaiappan, Sankari; Varghese, Sheeja; Jayakumar, Nadathur D; Prakasam, Gopinath

2017-09-01

Periodontal regeneration can be defined as complete restoration of lost periodontal tissues to their original architecture and function. A variety of treatment modalities have been proposed to achieve it. Plasma rich in growth factors (PRGF) is a concentrated suspension of growth factors that promotes restoration of lost periodontal tissues. The objective of the present study is to assess the effect of PRGF associated with guided tissue regeneration (GTR) versus GTR only in the treatment of intrabony defects (IBDs) in patients with chronic periodontitis (CP). Patients with CP (n = 14) with 42 contralateral 2- and 3-walled defects were randomly assigned to test (PRGF+GTR) and control (GTR alone) treatment groups. Clinical and radiographic assessments performed at baseline and after 6 months were: 1) gingival index (GI), 2) probing depth (PD), 3) clinical attachment level (CAL), 4) radiologic defect depth, and 5) bone fill. Comparison of parameters measured at baseline and after 6 months showed mean PD reduction of 3.37 ± 1.62 mm in the control group (P <0.001) and 4.13 ± 1.59 mm in the test group (P <0.001). There was a significant difference in mean change in CAL (P <0.001) in the control group (5.42 ± 1.99) and the test group (5.99 ± 1.77). Mean change in GI was 1.89 ± 0.32 and 1.68 ± 0.58 in the control group and test group, respectively, and the difference was statistically significant (P <0.001). When compared between groups, clinical parameters did not show any statistically significant variations. Mean radiographic bone fill was 1.06 ± 0.81 and 1.0 ± 0.97 in the control group and test group, respectively. However, the difference was not statistically significant. PRGF with GTR, as well as GTR alone, was effective in improving clinical and radiographic parameters of patients with CP at the 6-month follow-up. There was no additive effect of PRGF when used along with GTR in the treatment of IBDs in patients with CP in terms of both clinical and

Management of the Sequelae of Severe Congenital Abdominal Wall Defects

Directory of Open Access Journals (Sweden)

Sara Fuentes

2016-05-01

Full Text Available BackgroundThe survival rate of newborns with severe congenital abdominal wall defects has increased. After successfully addressing life-threatening complications, it is necessary to focus on the cosmetic and functional outcomes of the abdominal wall.MethodsWe performed a chart review of five cases treated in our institution.ResultsFive patients, ranging from seven to 18 years of age, underwent the following surgical approaches: simple approximation of the rectus abdominis fascia, the rectus abdominis sheath turnover flap, the placement of submuscular tissue expanders, mesh repair, or a combination of these techniques depending on the characteristics of each individual case.ConclusionsPatients with severe congenital abdominal wall defects require individualized surgical treatment to address both the aesthetic and functional issues related to the sequelae of their defects.

Reconstruction of the maxilla following hemimaxillectomy defects with scapular tip grafts and dental implants.

Science.gov (United States)

Mertens, Christian; Freudlsperger, Christian; Bodem, Jens; Engel, Michael; Hoffmann, Jürgen; Freier, Kolja

2016-11-01

Treatment of post-resective defects of the maxilla can be challenging and usually requires dental obturation or microvascular reconstruction. As compared to soft-tissue microvascular grafts, bone reconstruction can additionally allow for facial support and retention of dental implants. The aim of this study was to evaluate scapular tip grafts with respect to their applicability for maxillary reconstruction and their potential to retain dental implants for later dental rehabilitation. In this retrospective study, 14 patients with hemimaxillectomy defects were reconstructed with free scapular tip grafts, oriented horizontally, to rebuild the palate and alveolar ridge. After bone healing, three-dimensional virtual implant planning was performed, and a radiographic guide was fabricated to enable implant placement in the optimal anatomic and prosthetic position. All patients' mastication and speech were evaluated, along with the extent of defect closure, suitability of the graft sites for implant placement, and soft-tissue stability. Pre- and postsurgical radiographs were also evaluated. A good postoperative outcome was achieved in all patients, with complete closure of maxillary defects that were class II, according to the system of Brown and Shaw. Additional bone augmentation was necessary in two patients in order to increase vertical bone height. Patients were subsequently treated with 50 dental implants to retain dental prostheses. In all cases, additional soft-tissue surgery was necessary to achieve a long-term stable periimplant situation. No implants were lost during the mean observation period of 34 months. Due to its specific form, the scapular tip graft is well suited to reconstruct the palate and maxillary alveolar ridge and to enable subsequent implant-retained rehabilitation. Due to the limited bone volume, an accurate three-dimensional graft orientation is essential. Furthermore, most cases require additional soft-tissue surgery to achieve a long

Reconstruction of a midfacial defect using an intraoral-extraoral combination prosthesis employing magnets: a clinical report

OpenAIRE

Nair, Anoop; Regish, K M.; Shah, Farhan K.; Prithviraj, D R.

2012-01-01

Radical maxillectomy frequently leads to extended defects in hard and soft tissues that result in a connection between the oral cavities and orbit. If the defect cannot be surgically reconstructed, a combination prosthesis may be necessary to remedy dysfunction in patient function, comfort, esthetics. For minor defects, enlargement of the base of the intra oral prosthesis is generally sufficient. Resections that affect more than one third of the maxilla usually require an intra oral and an ex...

Mechanical Forces Exacerbate Periodontal Defects in Bsp-null Mice

Science.gov (United States)

Soenjaya, Y.; Foster, B.L.; Nociti, F.H.; Ao, M.; Holdsworth, D.W.; Hunter, G.K.; Somerman, M.J.

2015-01-01

Bone sialoprotein (BSP) is an acidic phosphoprotein with collagen-binding, cell attachment, and hydroxyapatite-nucleating properties. BSP expression in mineralized tissues is upregulated at onset of mineralization. Bsp-null (Bsp-/-) mice exhibit reductions in bone mineral density, bone turnover, osteoclast activation, and impaired bone healing. Furthermore, Bsp-/- mice have marked periodontal tissue breakdown, with a lack of acellular cementum leading to periodontal ligament detachment, extensive alveolar bone and tooth root resorption, and incisor malocclusion. We hypothesized that altered mechanical stress from mastication contributes to periodontal destruction observed in Bsp-/- mice. This hypothesis was tested by comparing Bsp-/- and wild-type mice fed with standard hard pellet diet or soft powder diet. Dentoalveolar tissues were analyzed using histology and micro–computed tomography. By 8 wk of age, Bsp-/- mice exhibited molar and incisor malocclusion regardless of diet. Bsp-/- mice with hard pellet diet exhibited high incidence (30%) of severe incisor malocclusion, 10% lower body weight, 3% reduced femur length, and 30% elevated serum alkaline phosphatase activity compared to wild type. Soft powder diet reduced severe incisor malocclusion incidence to 3% in Bsp-/- mice, supporting the hypothesis that occlusal loading contributed to the malocclusion phenotype. Furthermore, Bsp-/- mice in the soft powder diet group featured normal body weight, long bone length, and serum alkaline phosphatase activity, suggesting that tooth dysfunction and malnutrition contribute to growth and skeletal defects reported in Bsp-/- mice. Bsp-/- incisors also erupt at a slower rate, which likely leads to the observed thickened dentin and enhanced mineralization of dentin and enamel toward the apical end. We propose that the decrease in eruption rate is due to a lack of acellular cementum and associated defective periodontal attachment. These data demonstrate the importance of BSP

[Cartilage tissue reconstruction by the polymer biomaterials--early macroscopic and histological results].

Science.gov (United States)

Scierski, Wojciech; Polok, Aleksandra; Namysłowski, Grzegorz; Nozyński, Jerzy; Turecka, Lucyna; Urbaniec, Natalia; Pamuła, Elzbieta

2009-09-01

The surgical treatment of large cartilage defects in the region of head and neck is often impossible because of the atrophy of surrounding tissues and lack of suitable material for reconstruction. In the surgical treatment many of methods and reconstructive materials have been used. For many years the suitable synthetic material for the cartilage defects reconstruction has been searched for. Was to evaluate two different biomaterials with proper mechanical and biological features for the cartilage replacement. Two type of biomaterials in this study were used: resorbable polymer - poly(L-lactide-co-glycolide) (PLG) acting as a supportive matrix. A thin layer of sodium hyaluronate (Hyal) was also deposited on the surface as well in the pore walls of PLG scaffolds in order to provide biologically active molecules promoting differentiation and regeneration of the tissue. The studies were performed on the 50 animals--rabbits divided into 2 groups. The animals were operated in the general anaesthesia. The incision was done along the edge of the rabbit's auricle. Perichondrium and cartilage of the auricle on the surface 4 x 3 cm were prepared. Subperichondrically 1 x 1 cm fragment of the cartilage was removed by the scissors. This fragment was then replaced by the biomaterials: PLG in first group of 25 rabbits and PLG-Hyal in second group 25 rabbits. The tissues were sutured with polyglycolide Safil 3-0. The animals obtained Enrofloxacin for three days after the operation. Then 1, 4 and 12 weeks after the surgery the animals were painlessly euthanized by an overdose of Morbital. Implants and surrounding tissues were excised and observed macroscopically and using an optical microscope. In all the observation periods we observed proper macroscopic healing process of biomaterials. We didn't stated strong inflammatory process and necrosis around the implanted biomaterials. The histological and macroscopic examinations indicated that both materials developed in this study have

A Modified Rabbit Ulna Defect Model for Evaluating Periosteal Substitutes in Bone Engineering: A Pilot Study

Energy Technology Data Exchange (ETDEWEB)

El Backly, Rania M. [DIMES, University of Genova, Genova (Italy); IRCCS AOU San Martino–IST Istituto Nazionale per la Ricerca sul Cancro, Genova (Italy); Faculty of Dentistry, Alexandria University, Alexandria (Egypt); Chiapale, Danilo [IRCCS AOU San Martino–IST Istituto Nazionale per la Ricerca sul Cancro, Genova (Italy); Muraglia, Anita [Biorigen S.R.L., Genova (Italy); Tromba, Giuliana [Sincrotrone Trieste S.C.P.A., Trieste (Italy); Ottonello, Chiara [Biorigen S.R.L., Genova (Italy); Santolini, Federico [IRCCS AOU San Martino–IST Istituto Nazionale per la Ricerca sul Cancro, Genova (Italy); Cancedda, Ranieri; Mastrogiacomo, Maddalena, E-mail: maddalena.mastrogiacomo@unige.it [DIMES, University of Genova, Genova (Italy); IRCCS AOU San Martino–IST Istituto Nazionale per la Ricerca sul Cancro, Genova (Italy)

2015-01-06

The present work defines a modified critical size rabbit ulna defect model for bone regeneration in which a non-resorbable barrier membrane was used to separate the radius from the ulna to create a valid model for evaluation of tissue-engineered periosteal substitutes. Eight rabbits divided into two groups were used. Critical defects (15 mm) were made in the ulna completely eliminating periosteum. For group I, defects were filled with a nanohydroxyapatite poly(ester urethane) scaffold soaked in PBS and left as such (group Ia) or wrapped with a tissue-engineered periosteal substitute (group Ib). For group II, an expanded-polytetrafluoroethylene (e-PTFE) (GORE-TEX{sup ®}) membrane was inserted around the radius then the defects received either scaffold alone (group IIa) or scaffold wrapped with periosteal substitute (group IIb). Animals were euthanized after 12–16 weeks, and bone regeneration was evaluated by radiography, computed microtomography (μCT), and histology. In the first group, we observed formation of radio-ulnar synostosis irrespective of the treatment. This was completely eliminated upon placement of the e-PTFE (GORE-TEX{sup ®}) membrane in the second group of animals. In conclusion, modification of the model using a non-resorbable e-PTFE membrane to isolate the ulna from the radius was a valuable addition allowing for objective evaluation of the tissue-engineered periosteal substitute.

A Modified Rabbit Ulna Defect Model for Evaluating Periosteal Substitutes in Bone Engineering: A Pilot Study

International Nuclear Information System (INIS)

El Backly, Rania M.; Chiapale, Danilo; Muraglia, Anita; Tromba, Giuliana; Ottonello, Chiara; Santolini, Federico; Cancedda, Ranieri; Mastrogiacomo, Maddalena

2015-01-01

The present work defines a modified critical size rabbit ulna defect model for bone regeneration in which a non-resorbable barrier membrane was used to separate the radius from the ulna to create a valid model for evaluation of tissue-engineered periosteal substitutes. Eight rabbits divided into two groups were used. Critical defects (15 mm) were made in the ulna completely eliminating periosteum. For group I, defects were filled with a nanohydroxyapatite poly(ester urethane) scaffold soaked in PBS and left as such (group Ia) or wrapped with a tissue-engineered periosteal substitute (group Ib). For group II, an expanded-polytetrafluoroethylene (e-PTFE) (GORE-TEX ® ) membrane was inserted around the radius then the defects received either scaffold alone (group IIa) or scaffold wrapped with periosteal substitute (group IIb). Animals were euthanized after 12–16 weeks, and bone regeneration was evaluated by radiography, computed microtomography (μCT), and histology. In the first group, we observed formation of radio-ulnar synostosis irrespective of the treatment. This was completely eliminated upon placement of the e-PTFE (GORE-TEX ® ) membrane in the second group of animals. In conclusion, modification of the model using a non-resorbable e-PTFE membrane to isolate the ulna from the radius was a valuable addition allowing for objective evaluation of the tissue-engineered periosteal substitute.

Ultrasonic NDE Simulation for Composite Manufacturing Defects

Science.gov (United States)

Leckey, Cara A. C.; Juarez, Peter D.

2016-01-01

The increased use of composites in aerospace components is expected to continue into the future. The large scale use of composites in aerospace necessitates the development of composite-appropriate nondestructive evaluation (NDE) methods to quantitatively characterize defects in as-manufactured parts and damage incurred during or post manufacturing. Ultrasonic techniques are one of the most common approaches for defect/damage detection in composite materials. One key technical challenge area included in NASA's Advanced Composite's Project is to develop optimized rapid inspection methods for composite materials. Common manufacturing defects in carbon fiber reinforced polymer (CFRP) composites include fiber waviness (in-plane and out-of-plane), porosity, and disbonds; among others. This paper is an overview of ongoing work to develop ultrasonic wavefield based methods for characterizing manufacturing waviness defects. The paper describes the development and implementation of a custom ultrasound simulation tool that is used to model ultrasonic wave interaction with in-plane fiber waviness (also known as marcelling). Wavefield data processing methods are applied to the simulation data to explore possible routes for quantitative defect characterization.

Vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association with Mayer-Rokitansky-Küster-Hauser syndrome in co-occurrence

DEFF Research Database (Denmark)

Bjørsum-Meyer, Thomas; Herlin, Morten; Qvist, Niels

2016-01-01

Background: The vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome are rare conditions. We aimed to present two cases with the vertebral defect, anal atresia, cardiac...... defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser co-occurrence from our local surgical center and through a systematic literature search detect published cases. Furthermore, we aimed to collect existing knowledge...... in the embryopathogenesis and genetics in order to discuss a possible link between the vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome. Case presentation: Our first case was a white girl...

Dual approaches for defects condensation

Energy Technology Data Exchange (ETDEWEB)

Rougemont, Romulo; Grigorio, Leonardo de Souza; Wotzasek, Clovis [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Guimaraes, Marcelo Santos [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

2009-07-01

Full text. Due to the fact that the QCD running coupling constant becomes larger as we go into the low energy (or large distance) limit of the theory, a perturbative treatment of its infrared (IR) region is impossible. In particular, a formal mathematical demonstration of color confinement and a complete physical understanding of the exact mechanism that confines quarks and gluons are two missing points in our current knowledge of the IR-QCD. It was known that due to the Meissner effect of expulsion of magnetic fields in a electric condensate that usual superconductors should confine magnetic monopoles. That point led to the conjecture that the QCD vacuum could be a condensate of chromomagnetic monopoles, a dual superconductor (DSC). Such a chromomagnetic condensate should be responsible for the dual Meissner effect which is expected to lead to the confinement of color charges immersed in this medium. In dual superconductor models of color confinement, magnetic monopoles appear as topological defects in points of the space where the abelian projection becomes singular. Also, condensation of other kinds of defects such as vortices in superfluids and line-like defects in solids are responsible for a great variety of phase transitions, which once more proves the relevance of the subject. In the present work we review two methods that allow us to approach the condensation of defects: the Kleinert Mechanism (KM) and the Julia-Toulouse Mechanism (JTM). We show that in the limit where the vortex gauge field goes to zero, which we identify as the signature of the condensation of defects in the dual picture, these are two equivalent dual prescriptions for obtaining an effective theory for a phase where defects are condensed, starting from the fundamental theory defined in the normal phase where defects are diluted. (author)

Evaluation of Polyurethane Membrane as a Barrier in Treatment of Intrabony Defects

Directory of Open Access Journals (Sweden)

Haghighati F

2000-05-01

Full Text Available Clinical healing following guided tissue regeneration (GTR in intrabony pockets using a"npolyurethane membrane was compared to healing following gingival flap surgery (GFS."nTen patients with adult periodontitis and the presence of intrabony defects were selected. Oral hygenic"ntreatments were performed during a 4- weeks period prior to surgery."nOne intrabony defects on each patient was randomly chosen to be treated according to the guided tissue"nregeneration (GTR procedure. The other side received the control treatment GFS. Test group received"nthe GTP treatment including polyurethane membrane after reflecting the flap and curettage of defect."nHowever, flap surgery and curettage were done in control group."nThe patients were evaluated for changes in probing depth (PD, clinical attachment level (CAL,"nrecession changes in crestai resorting, and defect bone fill. Clinical examinations were performed again 6"nmonths post operatively."nThe average of (PD, (CAL and defect depth (DD before surgery in test group was 3.23, 13.87 and 7.3"nmm respectively and in control group was 3.1, 8.9, 7.4 mm. After 6 months the average of (PD, (CAL"nand (DD was 1.69, 1.68, 3.5 mm, respectively and in control group was 1.24, 1.09, and 2.90mm."nTest group and control group showed successful results in treatment of intrabony defects. Test group"nshowed better results than control."nNo significant difference was observed between two treatment procedures from the point of view of"npocket depth reduction, attachment gain, and recession."nThe bony fill and crestai resorption results suggest similar clinical potential of GTR procedures"ncompared to GFS in treatment of intrabony pocket. However, in order to gain future insight, larger"nsamples and longer observation periods should be evaluated.

Soft tissue reconstruction for calcaneal fractures or osteomyelitis.

Science.gov (United States)

Attinger, C; Cooper, P

2001-01-01

hardware is exposed, a muscle flap should cover the wound because of the extra blood supply it carries with it. The soft tissue option depends on the width of the wound. For wounds 1 cm wide or less, the options include allowing the wound to close by secondary intention (VAC), delayed primary closure, or a local muscle flap. For wounds 2 cm wide or less, allowing the wound to close by secondary intention (VAC) and a local muscle flap are the best options. For wider wounds, one has to assess whether the local muscle flap has sufficient bulk to close the defect. If it does, it is the simplest solution. If the local muscle is inadequate, a microsurgical free flap has to be used. The VAC sometimes can convert a large wound to a smaller wound so that a local muscle flap can be used. This procedure takes time, however, and adds to the cost of the repair.

Similar hyaline-like cartilage repair of osteochondral defects in rabbits using isotropic and anisotropic collagen scaffolds.

Science.gov (United States)

de Mulder, Eric L W; Hannink, Gerjon; van Kuppevelt, Toin H; Daamen, Willeke F; Buma, Pieter

2014-02-01

Lesions in knee joint articular cartilage (AC) have limited repair capacity. Many clinically available treatments induce a fibrous-like cartilage repair instead of hyaline cartilage. To induce hyaline cartilage repair, we hypothesized that type I collagen scaffolds with fibers aligned perpendicular to the AC surface would result in qualitatively better tissue repair due to a guided cellular influx from the subchondral bone. By specific freezing protocols, type I collagen scaffolds with isotropic and anisotropic fiber architectures were produced. Rabbits were operated on bilaterally and two full thickness defects were created in each knee joint. The defects were filled with (1) an isotropic scaffold, (2) an anisotropic scaffold with pores parallel to the cartilage surface, and (3) an anisotropic scaffold with pores perpendicular to the cartilage surface. Empty defects served as controls. After 4 (n=13) and 12 (n=13) weeks, regeneration was scored qualitatively and quantitatively using histological analysis and a modified O'Driscoll score. After 4 weeks, all defects were completely filled with partially differentiated hyaline cartilage tissue. No differences in O'Driscoll scores were measured between empty defects and scaffold types. After 12 weeks, all treatments led to hyaline cartilage repair visualized by increased glycosaminoglycan staining. Total scores were significantly increased for parallel anisotropic and empty defects over time (phyaline-like cartilage repair. Fiber architecture had no effect on cartilage repair.