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Sample records for fibrin glue scaffold

  1. Evaluation of bone matrix gelatin/fibrin glue and chitosan/gelatin composite scaffolds for cartilage tissue engineering.

    PubMed

    Wang, Z H; Zhang, J; Zhang, Q; Gao, Y; Yan, J; Zhao, X Y; Yang, Y Y; Kong, D M; Zhao, J; Shi, Y X; Li, X L

    2016-01-01

    This study was designed to evaluate bone matrix gelatin (BMG)/fibrin glue and chitosan/gelatin composite scaffolds for cartilage tissue engineering. Chondrocytes were isolated from costal cartilage of Sprague-Dawley rats and seeded on BMG/fibrin glue or chitosan/gelatin composite scaffolds. After different in vitro culture durations, the scaffolds were subjected to hematoxylin and eosin, Masson's trichrome, and toluidine blue staining, anti-collagen II and anti-aggrecan immunohistochemistry, and scanning electronic microscopy (SEM) analysis. After 2 weeks of culture, chondrocytes were distributed evenly on the surfaces of both scaffolds. Cell numbers and the presence of extracellular matrix components were markedly increased after 8 weeks of culture, and to a greater extent on the chitosan/gelatin scaffold. The BMG/fibrin glue scaffold showed signs of degradation after 8 weeks. Immunofluorescence analysis confirmed higher levels of collagen II and aggrecan using the chitosan/gelatin scaffold. SEM revealed that the majority of cells on the surface of the BMG/fibrin glue scaffold demonstrated a round morphology, while those in the chitosan/gelatin group had a spindle-like shape, with pseudopodia. Chitosan/gelatin scaffolds appear to be superior to BMG/ fibrin glue constructs in supporting chondrocyte attachment, proliferation, and biosynthesis of cartilaginous matrix components. PMID:27525846

  2. Fibrin glue in ophthalmology

    PubMed Central

    Panda, Anita; Kumar, Sandeep; Kumar, Abhiyan; Bansal, Raseena; Bhartiya, Shibal

    2009-01-01

    Suturing is a time consuming task in ophthalmology and suture induced irritation and redness are frequent problems. Postoperative wound infection and corneal graft rejection are examples of possible suture related complications. To prevent these complications, ophthalmic surgeons are switching to sutureless surgery. A number of recent developments have established tissue adhesives like cyanoacrylate glue and fibrin glue as attractive alternatives to sutures. A possible and promising new application for tissue adhesives is to provide a platform for tissue engineering. Currently, tissue glue is being used for conjunctival closure following pterygium and strabismus surgery, forniceal reconstruction surgery, amniotic membrane transplantation, lamellar corneal grafting, closure of corneal perforations and descematoceles, management of conjunctival wound leaks after trabeculectomy, lid surgery, adnexal surgery and as a hemostat to minimise bleeding. The purpose of this review is to discuss the currently available information on fibrin glue. PMID:19700876

  3. Fibrin glue is a candidate scaffold for long-term therapeutic protein expression in spontaneously differentiated adipocytes in vitro

    SciTech Connect

    Aoyagi, Yasuyuki; Kuroda, Masayuki; Asada, Sakiyo; Tanaka, Shigeaki; Konno, Shunichi; Tanio, Masami; Aso, Masayuki; Okamoto, Yoshitaka; Nakayama, Toshinori; Saito, Yasushi; Bujo, Hideaki

    2012-01-01

    Adipose tissue is expected to provide a source of cells for protein replacement therapies via auto-transplantation. However, the conditioning of the environment surrounding the transplanted adipocytes for their long-term survival and protein secretion properties has not been established. We have recently developed a preparation procedure for preadipocytes, ceiling culture-derived proliferative adipocytes (ccdPAs), as a therapeutic gene vehicle suitable for stable gene product secretion. We herein report the results of our evaluation of using fibrin glue as a scaffold for the transplanted ccdPAs for the expression of a transduced gene in a three-dimensional culture system. The ccdPAs secreted the functional protein translated from an exogenously transduced gene, as well as physiological adipocyte proteins, and the long viability of ccdPAs (up to 84 days) was dependent on the fibrinogen concentrations. The ccdPAs spontaneously accumulated lipid droplets, and their expression levels of the transduced exogenous gene with its product were maintained for at least 56 days. The fibrinogen concentration modified the adipogenic differentiation of ccdPAs and their exogenous gene expression levels, and the levels of exogenously transduced gene expression at the different fibrinogen concentrations were dependent on the extent of adipogenic differentiation in the gel. These results indicate that fibrin glue helps to maintain the high adipogenic potential of cultured adipocytes after passaging in a 3D culture system, and suggests that once they are successfully implanted at the transplantation site, the cells exhibit increased expression of the transduced gene with adipogenic differentiation.

  4. [Use of fibrin glue in gynecologic operations].

    PubMed

    Kulakov, V I; Gigauri, V S; Kulakov, V I; Gigauri, V S; Adamian, L V; Zhidkov, I L; Mynbaev, O A

    1990-11-01

    Anastomosing of the uterine horns in 98 experimental rats has employed a fibrin glue FK-1 (USSR) and Beriplast (FRG) or microsurgical techniques in a control group. Intactness and sealing of the anastomoses and the incidence of pelvic adhesions were assessed at 5 minutes, 1 hour and 1, 2, 3, 4, 5, and 6 days following the operation. The fibrin glue Beriplast was used clinically in 6 patients during reconstructive-plastic operations. The results with seamless anastomosing of uterine horns in rats using the fibrin glue and preliminary clinical evidence suggests a high effectiveness of the glue in gynecologic reconstructive plastic surgery.

  5. Uncultured Marrow Mononuclear Cells Delivered Within Fibrin Glue Hydrogels to Porous Scaffolds Enhance Bone Regeneration Within Critical-Sized Rat Cranial Defects

    PubMed Central

    Kretlow, James D.; Spicer, Patrick P.; Jansen, John A.; Vacanti, Charles A.; Kasper, F. Kurtis

    2010-01-01

    For bone tissue engineering, the benefits of incorporating mesenchymal stem cells (MSCs) into porous scaffolds are well established. There is, however, little consensus on the effects of or need for MSC handling ex vivo. Culture and expansion of MSCs adds length and cost, and likely increases risk associated with treatment. We evaluated the effect of using uncultured bone marrow mononuclear cells (bmMNCs) encapsulated within fibrin glue hydrogels and seeded into porous scaffolds to regenerate bone over 12 weeks in an 8-mm-diameter, critical-sized rat cranial defect. A full factorial experimental design was used to evaluate bone formation within model poly(L-lactic acid) and corraline hydroxyapatite scaffolds with or without platelet-rich plasma (PRP) and bmMNCs. Mechanical push-out testing, microcomputed tomographical analyses, and histology were performed. PRP showed no benefit for bone formation. Cell-laden poly(L-lactic acid) scaffolds without PRP required significantly greater force to displace from surrounding tissues than control (cell-free) scaffolds, but no differences were observed during push-out testing of coral scaffolds. For bone volume formation as analyzed by microcomputed tomography, significant positive overall effects were observed with bmMNC incorporation. These data suggest that bmMNCs may provide therapeutic advantages in bone tissue engineering applications without the need for culture, expansion, and purification. PMID:20715884

  6. Evolution of fibrin glue applicators.

    PubMed

    Marx, Gerard

    2003-10-01

    Fibrin glue (FG) is used worldwide as a potent surgical tool, which establishes hemostasis in wounds and also bonds tissue. The standard FG applicator is based on a dual-syringe system. This review, based mainly on the patent literature, describes the development of the quasi-standard dual syringe system as well as the rise of other FG applicator designs based on mechanical force (ratchet systems), Bernoulli gas flow, positive gas pressure, or electro-servo devices. The packaging of commercial FG components is reviewed within the context of "loading" the FG applicators and the need to minimize the number of needles required to access the packaged (vials) components. Parameters such as internal clogging, homogeneity of spray, the requirement for gas or vacuum house lines, the number of parts that must be handled, and the time required to assemble the applicator, load it, and have it ready for use are also discussed. A rating system is proposed that permits one to use such parameters to rank the various applicator designs, relative to the dual-syringe system. Hopefully, this review will stimulate the design of better FG applicators and packaging required for elective surgery, emergency treatments, and tissue engineering in the 21st century.

  7. Autologous fibrin glue in peripheral nerve regeneration in vivo.

    PubMed

    Choi, Byung-Ho; Han, Sang-Gyun; Kim, Sung-Hoon; Zhu, Shi-Jiang; Huh, Jin-Young; Jung, Jae-Hyung; Lee, Seoung-Ho; Kim, Byung-Yong

    2005-01-01

    The activity of several growth factors on peripheral nerve regeneration is reported. Autologous fibrin glue contains a large number of platelets, which release significant quantities of growth factors. In order to understand the role of autologous fibrin glue in peripheral nerve regeneration, a 15-mm rabbit peroneal nerve defect was repaired using a vein graft filled with autologous fibrin glue. Axonal regeneration was examined using histological and electrophysiological methods. The extent of axonal regeneration was superior when treated with autologous fibrin glue. Our data suggest that fibrin nets formed by fibrinogen, in combination with growth factors present in autologous fibrin glue, might effectively promote peripheral nerve regeneration in nerve defects.

  8. Enhanced angiogenesis and osteogenesis in critical bone defects by the controlled release of BMP-2 and VEGF: implantation of electron beam melting-fabricated porous Ti6Al4V scaffolds incorporating growth factor-doped fibrin glue.

    PubMed

    Lv, Jia; Xiu, Peng; Tan, Jie; Jia, Zhaojun; Cai, Hong; Liu, Zhongjun

    2015-06-24

    Electron beam melting (EBM)-fabricated porous titanium implants possessing low elastic moduli and tailored structures are promising biomaterials for orthopedic applications. However, the bio-inert nature of porous titanium makes reinforcement with growth factors (GFs) a promising method to enhance implant in vivo performance. Bone-morphogenic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) are key factors of angiogenesis and osteogenesis. Therefore, the present study is aimed at evaluating EBM-fabricated porous titanium implants incorporating GF-doped fibrin glue (FG) as composite scaffolds providing GFs for improvement of angiogenesis and osteogenesis in rabbit femoral condyle defects. BMP-2 and VEGF were added into the constituent compounds of FG, and then this GF-doped FG was subsequently injected into the porous scaffolds. In five groups of implants, angiogenesis and osteogenesis were evaluated at 4 weeks post-implantation using Microfil perfusion and histological analysis: eTi (empty scaffolds), cTi (containing undoped FG), BMP/cTi (containing 50 μg rhBMP-2), VEGF/cTi (containing 0.5 μg VEGF) and Dual/cTi (containing 50 μg rhBMP-2 and 0.5 μg VEGF). The results demonstrate that these composite implants are biocompatible and provide the desired gradual release of the bioactive growth factors. Incorporation of GF delivery, whether a single factor or dual factors, significantly enhanced both angiogenesis and osteogenesis inside the porous scaffolds. However, the synergistic effect of the dual factors combination was observable on angiogenesis but absent on osteogenesis. In conclusion, fibrin glue is a biocompatible material that could be employed as a delivery vehicle in EBM-fabricated porous titanium for controlled release of BMP-2 and VEGF. Application of this method for loading a porous titanium scaffold to incorporate growth factors is a convenient and promising strategy for improving osteogenesis of critical-sized bone defects.

  9. [Use of fibrin glue in surgery of parenchymatous organs].

    PubMed

    Gigauri, V S; Movchun, A A; Got'e, S V; Sheremet'eva, G F; Zhidkov, I L

    1989-04-01

    The article discusses the results of one of the first studies conducted in the Soviet Union on the use of various types of fibrinous glue in operations on the parenchymatous organs. The data of 67 experiments on rabbits and 20 clinical cases are reported. The experiments were carried out to test the efficacy of fibrinous glue application for arresting parenchymatous bleeding and appraise the air-tightness of wounds of the liver, spleen, and kidney by the method of hydropressure with morphological control. The effect of fibrinous glue made of Soviet-produced components was also tested in experiment. In the clinic, fibrinous glue was used for arresting bleeding from wounds of the liver and spleen and for ensuring air-tightness of anastomoses and filling residual cavities after removal of hepatic cysts. The hemostatic effect of various types of fibrinous glue was found to be high both in experiments and in the clinic. Essential advantage over synthetic cyanoacrylate glues was proved. It was noted that the use of fibrinous glue in operations on the parenchymatous organs is promising.

  10. Effect of collagen sponge and fibrin glue on bone repair

    PubMed Central

    SANTOS, Thiago de Santana; ABUNA, Rodrigo Paolo Flores; de ALMEIDA, Adriana Luisa Gonçalves; BELOTI, Marcio Mateus; ROSA, Adalberto Luiz

    2015-01-01

    ABSTRACT The ability of hemostatic agents to promote bone repair has been investigated using in vitro and in vivo models but, up to now, the results are inconclusive. Objective In this context, the aim of this study was to compare the potential of bone repair of collagen sponge with fibrin glue in a rat calvarial defect model. Material and Methods Defects of 5 mm in diameter were created in rat calvariae and treated with either collagen sponge or fibrin glue; untreated defects were used as control. At 4 and 8 weeks, histological analysis and micro-CT-based histomorphometry were carried out and data were compared by two-way ANOVA followed by Student-Newman-Keuls test when appropriated (p≤0.05). Results Three-dimensional reconstructions showed increased bone formation in defects treated with either collagen sponge or fibrin glue compared with untreated defects, which was confirmed by the histological analysis. Morphometric parameters indicated the progression of bone formation from 4 to 8 weeks. Additionally, fibrin glue displayed slightly higher bone formation rate when compared with collagen sponge. Conclusion Our results have shown the benefits of using collagen sponge and fibrin glue to promote new bone formation in rat calvarial bone defects, the latter being discreetly more advantageous. PMID:26814464

  11. Construction of a Corneal Stromal Equivalent with SMILE-Derived Lenticules and Fibrin Glue.

    PubMed

    Yin, Houfa; Qiu, Peijin; Wu, Fang; Zhang, Wei; Teng, Wenqi; Qin, Zhenwei; Li, Chao; Zhou, Jiaojie; Fang, Zhi; Tang, Qiaomei; Fu, Qiuli; Ma, Jian; Yang, Yabo

    2016-01-01

    The scarcity of corneal tissue to treat deep corneal defects and corneal perforations remains a challenge. Currently, small incision lenticule extraction (SMILE)-derived lenticules appear to be a promising alternative for the treatment of these conditions. However, the thickness and toughness of a single piece of lenticule are limited. To overcome these limitations, we constructed a corneal stromal equivalent with SMILE-derived lenticules and fibrin glue. In vitro cell culture revealed that the corneal stromal equivalent could provide a suitable scaffold for the survival and proliferation of corneal epithelial cells, which formed a continuous pluristratified epithelium with the expression of characteristic markers. Finally, anterior lamellar keratoplasty in rabbits demonstrated that the corneal stromal equivalent with decellularized lenticules and fibrin glue could repair the anterior region of the stroma, leading to re-epithelialization and recovery of both transparency and ultrastructural organization. Corneal neovascularization, graft degradation, and corneal rejection were not observed within 3 months. Taken together, the corneal stromal equivalent with SMILE-derived lenticules and fibrin glue appears to be a safe and effective alternative for the repair of damage to the anterior cornea, which may provide new avenues in the treatment of deep corneal defects or corneal perforations. PMID:27651001

  12. Construction of a Corneal Stromal Equivalent with SMILE-Derived Lenticules and Fibrin Glue

    PubMed Central

    Yin, Houfa; Qiu, Peijin; Wu, Fang; Zhang, Wei; Teng, Wenqi; Qin, Zhenwei; Li, Chao; Zhou, Jiaojie; Fang, Zhi; Tang, Qiaomei; Fu, Qiuli; Ma, Jian; Yang, Yabo

    2016-01-01

    The scarcity of corneal tissue to treat deep corneal defects and corneal perforations remains a challenge. Currently, small incision lenticule extraction (SMILE)-derived lenticules appear to be a promising alternative for the treatment of these conditions. However, the thickness and toughness of a single piece of lenticule are limited. To overcome these limitations, we constructed a corneal stromal equivalent with SMILE-derived lenticules and fibrin glue. In vitro cell culture revealed that the corneal stromal equivalent could provide a suitable scaffold for the survival and proliferation of corneal epithelial cells, which formed a continuous pluristratified epithelium with the expression of characteristic markers. Finally, anterior lamellar keratoplasty in rabbits demonstrated that the corneal stromal equivalent with decellularized lenticules and fibrin glue could repair the anterior region of the stroma, leading to re-epithelialization and recovery of both transparency and ultrastructural organization. Corneal neovascularization, graft degradation, and corneal rejection were not observed within 3 months. Taken together, the corneal stromal equivalent with SMILE-derived lenticules and fibrin glue appears to be a safe and effective alternative for the repair of damage to the anterior cornea, which may provide new avenues in the treatment of deep corneal defects or corneal perforations. PMID:27651001

  13. Use of autologous fibrin glue for endoscopic treatment of esophageal lesions

    PubMed Central

    Lucas, Matthias; Seeber, Petra

    2015-01-01

    Background and study aims: Esophageal leaks are a potentially life-threatening condition. One treatment option is injection therapy with commercially available fibrin glue. We describe herein a method to close esophageal leaks by injecting autologous fibrin glue prepared exclusively with the patient's own blood. PMID:26528493

  14. Bonding of synthetic hydrogels with fibrin as the glue to engineer hydrogel-based biodevices.

    PubMed

    Nagamine, Kuniaki; Okamoto, Kohei; Kaji, Hirokazu; Nishizawa, Matsuhiko

    2014-07-01

    We show the fibrous protein fibrin can serve as biocompatible glue with which to bind synthetic cationic or anionic hydrogels together. Both the bonding to and detachment from the hydrogels by fibrin (gelation and degradation, respectively) proceeded enzymatically under physiological conditions. We built a hydrogel-based actuator to demonstrate the method.

  15. Fibrin glue achieves hemostasis in patients with coagulation disorders.

    PubMed

    Kram, H B; Nathan, R C; Stafford, F J; Fleming, A W; Shoemaker, W C

    1989-03-01

    Fibrin glue (FG), made with highly concentrated human fibrinogen and clotting factors, was used to achieve parenchymal organ hemostasis in patients with disordered coagulation secondary to massive transfusion, chronic disease, and disseminated intravascular coagulation; it was effective in controlling liver hemorrhage in seven patients and in the performance of a splenorrhaphy in one other patient. The coagulation profile was grossly abnormal in all patients, and the mean +/- SD intraoperative blood loss was 5.1 +/- 4.2 L; patients received 14 +/- 10 U of blood perioperatively. The amount of FG required to achieve hemostasis varied directly with the extent of injury and intraoperative blood loss (r = .84), and all patients with a blood loss greater than 4 L required at least 25 mL of FG to stop bleeding. Two patients died postoperatively secondary to cardiac arrest and adult respiratory distress syndrome. Because FG does not depend on adequate platelet or clotting factor levels to be effective, it is especially useful in patients with parenchymal organ hemorrhage and disordered coagulation.

  16. Microvascular anastomosis using fibrin glue and venous cuff in rat carotid artery.

    PubMed

    Sacak, Bulent; Tosun, Ugur; Egemen, Onur; Sakiz, Damlanur; Ugurlu, Kemal

    2015-04-01

    Conventional anastomosis with interrupted sutures can be time-consuming, can cause vessel narrowing, and can lead to thrombosis at the site of repair. The amount of suture material inside the lumen can impair the endothelium of the vessel, triggering thrombosis. In microsurgery, fibrin sealants have the potential beneficial effects of reducing anastomosis time and promoting accurate haemostasis at the anastomotic site. However, there has been a general reluctance to use fibrin glue for microvascular anastomoses because the fibrin polymer is highly thrombogenic and may not provide adequate strength. To overcome these problems, a novel technique was defined for microvascular anastomosis with fibrin glue and a venous cuff. Sixty-four rats in two groups are included in the study. In the experimental group (n = 32), end-to-end arterial anastomosis was performed with two stay sutures, fibrin glue, and a venous cuff. In the control group (n = 32), conventional end-to-end arterial anastomosis was performed. Fibrin glue assisted anastomosis with a venous cuff took less time, caused less bleeding at the anastomotic site, and achieved a patency rate comparable to that provided by the conventional technique. Fibrin sealant assisted microvascular anastomosis with venous cuff is a rapid, easy, and reliable technique compared to the end-to-end arterial anastomosis.

  17. Hybrid composites of calcium phosphate granules, fibrin glue, and bone marrow for skeletal repair.

    PubMed

    Le Nihouannen, Damien; Goyenvalle, Eric; Aguado, Eric; Pilet, Paul; Bilban, Melitta; Daculsi, Guy; Layrolle, Pierre

    2007-05-01

    Synthetic bone substitutes, such as calcium phosphate ceramics, give good results in clinical applications. In order to adapt to surgical sites, bioceramics come in the form of blocks or granules, and are either dense or porous. Combining these bioceramics with fibrin glue provides a mouldable and self-hardening composite biomaterial with the biochemical properties of each component. Critical-sized defects in the femoral condyle of rabbits were filled with TricOs/fibrin glue/bone marrow hybrid/composite material. The TricOs granules (1-2 mm) were composed of hydroxyapatite and beta tricalcium phosphate (60/40 in weight). The fibrin glue was composed of fibrinogen, thrombin and other biological factors and mixed with MBCP granules either simultaneously or sequentially. Bone marrow was also added to the MBCP/fibrin composite prior to filling the defects. After 3, 6, 12, and 24 weeks of implantation, the newly-formed bone was analysed with histology, histomorphometry and mechanical tests. The newly-formed bone had grown centripetally. Simultaneous application of fibrin glue showed better results for mechanical properties than sequential application after 6 weeks. Around 40% of bone had formed after 24 weeks in the three groups. Although the addition of bone marrow did not improve bone formation, the MBCP/fibrin material could be used in clinical bone filling applications. PMID:17117470

  18. Percutaneous sclerotherapy of juvenile nasopharyngeal angiofibroma using fibrin glue combined with OK-432 and bleomycin.

    PubMed

    Chen, Wei-liang; Huang, Zhi-quan; Li, Jin-song; Chai, Qiang; Zhang, Da-ming

    2010-04-01

    The purpose of this study was to determine the appropriate conditions for percutaneous sclerotherapy of juvenile nasopharyngeal angiofibroma using fibrin glue combined with OK-432 and bleomycin. Three patients with juvenile nasopharyngeal angiofibroma were treated with an injection of fibrin glue combined with OK-432 and bleomycin. No major complications occurred in any of the patients. The follow-up period ranged from 12 to 14 months. The following outcomes were obtained: one lesion was completely involuted and two lesions were mostly involuted. All of the patients had normal liver and kidney function. Additionally, none of the patients presented with hematologic toxic effects or signs of pulmonary involvement. Percutaneous sclerotherapy using fibrin glue combined with OK-432 and bleomycin provided a simple, safe, and reliable alternative treatment for juvenile nasopharyngeal angiofibroma.

  19. Scaffold architecture and fibrin gels promote meniscal cell proliferation

    SciTech Connect

    Pawelec, K. M. E-mail: jw626@cam.ac.uk; Best, S. M.; Cameron, R. E.; Wardale, R. J. E-mail: jw626@cam.ac.uk

    2015-01-01

    Stability of the knee relies on the meniscus, a complex connective tissue with poor healing ability. Current meniscal tissue engineering is inadequate, as the signals for increasing meniscal cell proliferation have not been established. In this study, collagen scaffold structure, isotropic or aligned, and fibrin gel addition were tested. Metabolic activity was promoted by fibrin addition. Cellular proliferation, however, was significantly increased by both aligned architectures and fibrin addition. None of the constructs impaired collagen type I production or triggered adverse inflammatory responses. It was demonstrated that both fibrin gel addition and optimized scaffold architecture effectively promote meniscal cell proliferation.

  20. Fibrin glue repair leads to enhanced axonal elongation during early peripheral nerve regeneration in an in vivo mouse model

    PubMed Central

    Koulaxouzidis, Georgios; Reim, Gernot; Witzel, Christian

    2015-01-01

    Microsurgical suturing is the gold standard of nerve coaptation. Although literature on the usefulness of fibrin glue as an alternative is becoming increasingly available, it remains contradictory. Furthermore, no data exist on how both repair methods might influence the morphological aspects (arborization; branching) of early peripheral nerve regeneration. We used the sciatic nerve transplantation model in thy-1 yellow fluorescent protein mice (YFP; n = 10). Pieces of nerve (1cm) were grafted from YFP-negative mice (n = 10) into those expressing YFP. We performed microsuture coaptations on one side and used fibrin glue for repair on the contralateral side. Seven days after grafting, the regeneration distance, the percentage of regenerating and arborizing axons, the number of branches per axon, the coaptation failure rate, the gap size at the repair site and the time needed for surgical repair were all investigated. Fibrin glue repair resulted in regenerating axons travelling further into the distal nerve. It also increased the percentage of arborizing axons. No coaptation failure was detected. Gap sizes were comparable in both groups. Fibrin glue significantly reduced surgical repair time. The increase in regeneration distance, even after the short period of time, is in line with the results of others that showed faster axonal regeneration after fibrin glue repair. The increase in arborizing axons could be another explanation for better functional and electrophysiological results after fibrin glue repair. Fibrin glue nerve coaptation seems to be a promising alternative to microsuture repair. PMID:26330844

  1. Fibrin glue coating of the surgical surfaces may facilitate formation of a successful bleb in trabeculectomy surgery.

    PubMed

    Sakarya, Yasar; Sakarya, Rabia; Kara, Selcuk; Soylu, Tulay

    2011-08-01

    Trabeculectomy is commonly conducted when medical therapy fails to control intraocular pressure (IOP). The success of trabeculectomy for the treatment of glaucoma depends on the wound-healing response at the subconjunctival filtering bleb site. Postoperative scar formation is a serious problem in this surgery. Current strategies to counteract scarring include local antimetabolite treatment, which is associated with severe side effects, limiting its application. Therefore, additional means to safely modulate wound healing are desirable. In ophthalmic surgery, fibrin glue is used mainly for sealing and hemostatics purpose. Fibrin glue coating of tenon face of conjunctiva, scleral surface, reverse face of scleral flap and scleral bed with insoluble fibrin glue can halt both ooze bleeding and vascular leakage. By retarding the first step of wound healing, less postoperative inflammation may occur. Additionally aqueous humor flows through a fibrin glue coated interface. Therefore, we hypothesize that fibrin glue coating of the surgical surfaces in trabeculectomy surgery may yield less subconjunctival fibrosis and more successful bleb. To the best of our knowledge, no basic research has yet been performed regarding fibrin glue coating for halting the vascular leakage and easing the aqueous drainage into subconjunctival space in glaucoma surgery.

  2. Percutaneous sclerotherapy of sialoceles after parotidectomy with fibrin glue, OK-432, and bleomycin.

    PubMed

    Chen, Wei-liang; Zhang, Li-ping; Huang, Zhi-quan; Zhou, Bin

    2013-12-01

    We evaluated the curative effect of fibrin glue combined with OK-432 (streptococcal pyrogenic exotoxin A, Picibanil™) and bleomycin on 9 patients with sialoceles after parotidectomy. The primary lesions included pleomorphic adenomas in 6 cases and Warthin's tumours in 3 cases. After a sialocele had been diagnosed each patient had repeated aspirations and pressure dressings for 3-4 weeks, but these treatments failed. The patients were then treated with percutaneous sclerotherapy with the injection of fibrin glue 8-10 ml combined with OK-432 5 mg and bleomycin 15 mg. All the sialoceles disappeared completely after a single procedure in 2-3 weeks. The patients have been followed up for more than 6 months with no evidence of recurrent sialocele or injury to the facial nerve related to sclerotherapy. This simple, safe technique can be successfully used to treat sialoceles after parotidectomy.

  3. [Use of human fibrin glue (Tissucol) in the treatment of recurrent fistulas].

    PubMed

    La Torre, F; Pascarella, G; Nicolai, A P; Pontone, P; Montori, A

    1995-05-01

    In this study, the treatment of either primitive or secondary abdominal relapsed fistulas with Human Fibrin Glue (Tissucol) is reported. Twelve patients with different types of fistulas were treated in day hospital with the above mentioned procedure. Apart from two patients, the good percentage of success obtained in a short period of time is stressed. Results show that such a technique may be favourably adopted, nevertheless a correct first surgical procedure is recommended.

  4. The Role of Fibrin Glue Polypropylene Mesh Fixation in Open Inguinal Hernia Repair

    PubMed Central

    Odobasic, Amer; Krdzalic, Goran; Hodzic, Mirsad; Hasukic, Sefik; Sehanovic, Aida; Odobasic, Ademir

    2014-01-01

    ABSTRACT The aim: of this study was to compare two methods of polypropylene mesh fixation for inguinal hernia repair according to Lichtenstein using fibrin glue and suture fixation. Material and Methods: The study included 60 patients with unilateral inguinal hernia, divided into two groups of 30 patients – Suture fixation and fibrin glue fixation. All patients were analyzed according to: age, gender, body mass index (BMI), indication for surgery–the type, localization and size of the hernia, preoperative level of pain and the type of surgery. Overall postoperative complications and the patient’s ability to return to regular activities were followed for 3 months. Results and discussion: Statistically significant difference in the duration of surgery, pain intensity and complications (p<0.05) were verified between method A, the group of patients whose inguinal hernia was repaired using polypropylene mesh–fibrin glue and method B, where inguinal hernia was repaired with polypropylene mesh using suture fixation. Given the clinical research, this systematic review of existing results on the comparative effectiveness, will help in making important medical decisions about options for surgical treatment of inguinal hernia. Conclusions: The results of this study may impact decision making process for recommendations of methods of treatment by professional associations, making appropriate decisions on hospital procurement of materials, as well as coverage of health funds and insurance. PMID:24937929

  5. Effect of Fibrin Glue on the Biomechanical Properties of Human Descemet's Membrane

    PubMed Central

    Chaurasia, Shyam S.; Champakalakshmi, Ravi; Li, Ang; Poh, Rebekah; Tan, Xiao Wei; Lakshminarayanan, Rajamani; Lim, Chwee T.; Tan, Donald T.; Mehta, Jodhbir S.

    2012-01-01

    Background Corneal transplantation has rapidly evolved from full-thickness penetrating keratoplasty (PK) to selective tissue corneal transplantation, where only the diseased portions of the patient's corneal tissue are replaced with healthy donor tissue. Descemet's membrane endothelial keratoplasty (DMEK) performed in patients with corneal endothelial dysfunction is one such example where only a single layer of endothelial cells with its basement membrane (10–15 µm in thickness), Descemet's membrane (DM) is replaced. It is challenging to replace this membrane due to its intrinsic property to roll in an aqueous environment. The main objective of this study was to determine the effects of fibrin glue (FG) on the biomechanical properties of DM using atomic force microscopy (AFM) and relates these properties to membrane folding propensity. Methodology/Principal Findings Fibrin glue was sprayed using the EasySpray applicator system, and the biomechanical properties of human DM were determined by AFM. We studied the changes in the “rolling up” tendency of DM by examining the changes in the elasticity and flexural rigidity after the application of FG. Surface topography was assessed using scanning electron microscopy (SEM) and AFM imaging. Treatment with FG not only stabilized and stiffened DM but also led to a significant increase in hysteresis of the glue-treated membrane. In addition, flexural or bending rigidity values also increased in FG-treated membranes. Conclusions/Significance Our results suggest that fibrin glue provides rigidity to the DM/endothelial cell complex that may aid in subsequent manipulation by maintaining tissue integrity. PMID:22662156

  6. Fibrinogen and thrombin concentrations are critical for fibrin glue adherence in rat high-risk colon anastomoses

    PubMed Central

    Buen, Eliseo Portilla-de; Orozco-Mosqueda, Abel; Leal-Cortés, Caridad; Vázquez-Camacho, Gonzalo; Fuentes-Orozco, Clotilde; Alvarez-Villaseñor, Andrea Socorro; Macías-Amezcua, Michel Dassaejv; González-Ojeda, Alejandro

    2014-01-01

    OBJECTIVE: Fibrin glues have not been consistently successful in preventing the dehiscence of high-risk colonic anastomoses. Fibrinogen and thrombin concentrations in glues determine their ability to function as sealants, healers, and/or adhesives. The objective of the current study was to compare the effects of different concentrations of fibrinogen and thrombin on bursting pressure, leaks, dehiscence, and morphology of high-risk ischemic colonic anastomoses using fibrin glue in rats. METHODS: Colonic anastomoses in adult female Sprague-Dawley rats (weight, 250-350 g) treated with fibrin glue containing different concentrations of fibrinogen and thrombin were evaluated at post-operative day 5. The interventions were low-risk (normal) or high-risk (ischemic) end-to-end colonic anastomoses using polypropylene sutures and topical application of fibrinogen at high (120 mg/mL) or low (40 mg/mL) concentrations and thrombin at high (1000 IU/mL) or low (500 IU/mL) concentrations. RESULTS: Ischemia alone, anastomosis alone, or both together reduced the bursting pressure. Glues containing a low fibrinogen concentration improved this parameter in all cases. High thrombin in combination with low fibrinogen also improved adherence exclusively in low-risk anastomoses. No differences were detected with respect to macroscopic parameters, histopathology, or hydroxyproline content at 5 days post-anastomosis. CONCLUSIONS: Fibrin glue with a low fibrinogen content normalizes the bursting pressure of high-risk ischemic left-colon anastomoses in rats at day 5 after surgery. PMID:24714834

  7. Fibrin glue-assisted for the treatment of corneal perforations using glycerin-cryopreserved corneal tissue

    PubMed Central

    Dong, Nuo; Li, Cheng; Chen, Wen-Sheng; Qin, Wen-Juan; Xue, Yu-Hua; Wu, Hu-Ping

    2014-01-01

    AIM To evaluate the outcomes and safety of lamellar keratoplasty (LK) assisted by fibrin glue in corneal perforations. METHODS Six eyes of 6 patients affected by different corneal pathologies (2 posttraumatic corneal scar and 3 bacterial keratitis) underwent LK procedures by using fibrin glue. The mean corneal perforation diameter was 1.35±0.64mm (range, 0.7-2.5mm), and the greatest diameter of the ulcerative stromal defect was 2.47±0.77mm in average (range, 1.5-3.5mm). The donor corneal lamella diameters were 0.20-mm larger and thicker than the recipient to restore a physiologic corneal thickness and shape: mean donor diameter was 8.34±0.28mm (range, 8.2-8.7mm) and mean thickness was 352±40.27mm (range, 220-400mm). Mean follow-up was 7.33±1.97 months (range, 6-11 months). Postoperatively, the graft status, graft clarity, anterior chamber response, the visual prognosis, intraocular pressures, and postoperative complications were recorded. RESULTS All the corneal perforations were successfully healed after the procedure. The best-corrected visual acuity (BCVA) ranged from 20/1 000 to 20/50 in their initial presentation, and from 20/100 to 20/20 in their last visit, showed increase in all the patients. No major complications such as graft dislocation and graft failure were noted. Neovascularization developed in the superficial stroma of donor graft in 1 case. High intraocular pressure developed on day 2 after surgery, while was remained in normal range after application of anti-glaucomatous eyedrops for 1 week in 1 case. CONCLUSION Fibrin glue-assisted sutureless LK is valuable for maintaining the ocular integrity in the treatment of corneal perforations. PMID:24634865

  8. Endoluminal embolization of bilateral atherosclerotic common iliac aneurysms with fibrin tissue glue (Beriplast)

    SciTech Connect

    Beese, Richard C.; Tomlinson, Mark A.; Buckenham, Timothy M.

    2000-05-15

    The standard surgical approach to nonleaking iliac aneurysms found at repair of a leaking abdominal aortic aneurysm is to minimize the operative risk by repairing the abdominal aorta only. This means that the bypassed iliac aneurysms may have to be repaired later. As this population of patients are usually elderly with coexisting medical problems, interventional radiology is being used to embolize these aneurysms, thus avoiding the morbidity and mortality associated with further general anesthesia and surgery. Various materials and stents have been reported to be effective in the treatment of iliac aneurysms. We report the successful use of endoluminal fibrin tissue glue (Beriplast) to treat two large iliac aneurysms in a patient who had had a previous abdominal aortic aneurysm repair. We discuss the technique involved and the reasons why we used tissue glue in this patient.

  9. Percutaneous sclerotherapy of arteriovenous malformations of the face using fibrin glue combined with OK-432 and bleomycin after embolisation.

    PubMed

    Zhao, Xiao-peng; Huang, Zhi-quan; Chen, Wei-liang; Wang, You-yuan; Lin, Zhao-yu

    2016-02-01

    Congenital arteriovenous malformations (AVM) in the maxillofacial region are rare, but potentially life-threatening, vascular lesions. Here we review our experience of 13 patients with AVM of the facial soft tissues who were treated using percutaneous sclerotherapy with fibrin glue combined with OK-432 and bleomycin after embolisation. The mean (range) follow-up was 27 (14-58) months. Three of the lesions were completely controlled, eight were nearly completely controlled, and the other two were partly controlled. Our experience is that percutaneous sclerotherapy of arteriovenous malformations of the face using fibrin glue combined with OK-432 and bleomycin after embolisation is safe and effective.

  10. Effect of intraoperative platelet-rich plasma and fibrin glue application on skin flap survival.

    PubMed

    Findikcioglu, Fulya; Findikcioglu, Kemal; Yavuzer, Reha; Lortlar, Nese; Atabay, Kenan

    2012-09-01

    The experiment was designed to compare the effect of intraoperative platelet-rich plasma (PRP) and fibrin glue application on skin flap survival. In this study, bilateral epigastric flaps were elevated in 24 rats. The right-side flaps were used as the control of the left-side flaps. Platelet-rich plasma, fibrin glue, and thrombin had been applied under the flap sites in groups 1, 2, and 3, respectively. Five days later, all flap pedicles were ligated. Necrotic area measurements, microangiography, and histologic and immunohistochemical evaluations were performed to compare the groups. Platelet-rich plasma reduced necrotic area percentages as compared with other groups. Histologically and microangiographically increased number of arterioles were observed in PRP groups. Thrombin when used alone increased flap necrosis. Vascular endothelial growth factor, platelet-derived growth factor, and transforming growth factor β3 primary antibody staining showed increased neovascularization and reepithelialization in all PRP-applied flaps. This study demonstrated that PRP, when applied intraoperatively under the skin flap, may enhance flap survival. Thrombin used alone was found to be unsuitable in flap surgery.

  11. Successful Treatment of Congenital Chyloperitoneum with Platelet-Rich Fibrin Glue

    PubMed Central

    Joudi, Marjan; Alamdari, Daryoush Hamidi; Rahimi, Hamid-Reza

    2013-01-01

    Background Congenital chyloperitoneum is an uncommon clinical condition. A few cases of congenital chyloperitoneum in children have been described who were treated in a variety of methods. Case Presentation Congenital chyloperito was diagnosed in a 5-day-old baby boy with a significant abdominal distension. Due to the failed conservative managements by medium-chain triglycerides (MCT) enriched milk and partial parenteral nutrition (PPN), the authors tried platelet rich fibrin glue (PRFG) as an alternative choice which was applied through an already inserted intra-abdominal catheter. PRFG successfully stopped the lymph leakage from all over the small intestinal mesentery; thereby PRFG may be considered as an effective alternative treatment before surgical intervention. Conclusion Applying PRFG is an easy, safe, and effective alternative option that may be used to close the chylous ascites lymph leakage in children if conservative management with PPN fails. PMID:23795263

  12. Preservation of the cardiac function in infarcted rat hearts by the transplantation of adipose-derived stem cells with injectable fibrin scaffolds.

    PubMed

    Zhang, Xuelian; Wang, Haibin; Ma, Xiang; Adila, Azhati; Wang, Baozhu; Liu, Fen; Chen, Bangdang; Wang, Changyong; Ma, Yitong

    2010-12-01

    Cell-based therapy can improve cardiac function but is limited by the low cell retention and survival within ischemic tissues. Injectable cardiac tissue engineering aims to support cell-based therapies and enhance their efficacy for cardiac diseases. So far, no research has been devoted to studying the usefulness of the combination of fibrin glue (as scaffold) and adipose-derived stem cells (ADSCs) to treat myocardial infarction. In our study, the rat ADSCs were isolated from subcutaneous adipose tissues. The surface phenotype of these cells was analyzed by flow cytometry. The fibrin glue was then co-injected with ADSCs into the left ventricular wall of rat infarction models. The structure and functional consequences of transplantation were determined by detailed histological analysis and echocardiography. Most cultured ADSCs expressed CD105 and CD90, and were negative for CD34 and CD45. After injection, both the 24-h cell retention and four-week graft size were significantly higher and larger in the Fibrin + ADSCs group than those of the ADSCs group alone (P < 0.01). The heart function improved significantly in the Fibrin + ADSCs group compared with that of the ADSCs group four weeks after transplantation (P < 0.01). In addition, the arteriole densities within the infarcted area improved significantly in the Fibrin + ADSCs group compared with those in the ADSCs group four weeks after transplantation (P < 0.01). In conclusion, the ADSCs with the fibrin glue has the therapeutic potential to improve the function of infarcted hearts. The method of in situ injectable tissue engineering combining fibrin glue with ADSCs is promising clinically. PMID:21127347

  13. Preparation and characterization of human thrombin for use in a fibrin glue.

    PubMed

    Rock, G; Neurath, D; Semple, E; Harvey, M; Freedman, M

    2007-06-01

    Cryoprecipitate is frequently combined with thrombin to produce a fibrin sealant to enhance haemostasis during surgical procedures. We evaluated the thrombin produced from plasma using the Thrombin Processing Device (TPD)trade mark (Thermogenesis, Rancho Cordova, CA, USA). Plasma (250 mL) was processed in the CryoSeal FS System using the CP-3 disposable to produce cryoprecipitate by automated freezing and thawing. Simultaneously, thrombin was generated using the attached TPD. The cryoprecipitate and thrombin were harvested after approximately 50 min and then frozen and stored at -80 degrees C until analysis of total protein, fibrinogen, factor VIII (FVIII) activity, von Willebrand factor (vWF) and thrombin activity. Sodium dodecyl sulphate (SDS) gel electrophoresis was used to compare thrombin. After combining the thrombin with cryoprecipitate, the rate of clot initiation and strength was measured using a Thromboelastograph (TEG) (Haemoscope Corp, Skokie, IL, USA). Cryoprecipitate was produced, with a fibrinogen concentration of 22 +/- 7.7 g L(-1) (20 +/- 2% recovery), FVIII activity of 14.2 +/- 4.0 IU mL(-1) and vWF of 19.9 +/- 5.2 IU mL(-1). The separate thrombin product had a concentration of 64.3 +/- 16.7 IU mL(-1) of thrombin and a total protein of 0.39 +/- 0.1 g, with SDS gel electrophoresis showing a major band at 37 kD, as did the commercial human thrombin. The TEG curves of cryoprecipitate and TPD-produced or commercial thrombin were compared. The R values (time to clot initiation) were somewhat slower with the TPD-produced thrombin, but the maximum strength (MA) of the clots was similar. In conclusion, human thrombin can be produced during automated cryoprecipitate production. This thrombin is in sufficient concentration to initiate clotting and cross-linking of fibrin from cryoprecipitate to produce an entirely autologous fibrin glue.

  14. Percutaneous sclerotherapy of massive macrocystic lymphatic malformations of the face and neck using fibrin glue with OK-432 and bleomycin.

    PubMed

    Chen, W-l; Huang, Z-q; Chai, Q; Zhang, D-m; Wang, Y-y; Wang, H-j; Wang, L; Fan, S

    2011-06-01

    Picibanil (OK-432) and bleomycin have been used as alternative sclerosing agents for lymphatic malformations. This study evaluated the clinical curative effect of sclerotherapy using fibrin glue combined with OK-432 and bleomycin for the treatment of macrocystic lymphatic malformations of the face and neck. Fifteen paediatric patients (6 males; 9 females, aged 13 months to 14 years) who had received percutaneous sclerotherapy for massive macrocystic lymphatic malformations of the face and neck were retrospectively reviewed. Affected regions included the neck, parotid region and parapharynx, mouth floor, face and cheek, and orbital regions. All patients showed preoperative symptoms of space-occupying lesions between 4 cm × 5 cm and 12 cm × 16 cm in size. Fibrin glue with OK-432 and bleomycin was injected under general anaesthesia. All patients received preoperative and follow-up CT scans. Outcomes were assessed by three surgeons. All patients exhibited mid-facial swelling for 3-4 weeks after surgery, but no major complications. Follow-up periods ranged from 8 to 16 months. Eight lesions were completely involuted, five were mostly involuted, and two were partially involuted. Percutaneous sclerotherapy using fibrin glue with OK-432 and bleomycin provided a simple, safe, and reliable alternative treatment for massive macrocystic lymphatic malformations of the face and neck.

  15. Fibrin glue eliminates the need for packing after complex liver injuries.

    PubMed Central

    Feinstein, A. J.; Varela, J. E.; Cohn, S. M.; Compton, R. P.; McKenney, M. G.

    2001-01-01

    Hemostasis after traumatic liver injury can be extremely difficult to obtain, particularly in coagulopathic patients who have suffered extensive liver damage. We determined the ability of a fibrin glue preparation (FG) to terminate ongoing bleeding using a new, clinically relevant porcine model of complex hepatic injury. Anesthetized swine (n = 6, 18 to 19 kg) received an external blast to the right upper abdomen and were immediately anticoagulated with intravenous heparin (200 u/kg). Uncontrolled hemorrhage from blast continued from time of injury (t = 0 minutes) to t = 15 minutes. Lactated Ringer's solution was infused to keep mean arterial pressure (MAP) > 80 mm Hg until the end of experiment (t = 90 minutes). Animals underwent routine surgical techniques to control bleeding, and FG was employed in the event these measures failed. Estimated blood loss and fluid resuscitation volume were measured. Serial MAP, arterial base excess, and temperature were recorded. Animals were severely injured with significant blood loss prior to laparotomy (26 +/- 6 cc/kg) and during routine surgical efforts to arrest hemorrhage (11 +/- 2 cc/kg). Bleeding could not be controlled with standard techniques in any animal. FG rapidly controlled hemorrhage and eliminated the need for packing. Re-bleeding was noted in only one animal (portal vein injury). FG can control severe hepatic hemorrhage when surgical techniques fail. Further work in the clinical arena is warranted to determine the potential benefits of FG in arresting hemorrhage in hemodynamically unstable coagulopathic patients with complex hepatic injuries. PMID:11769337

  16. THE ROLE OF FIBRIN GLUE AND SUTURE ON THE FIXATION OF ULTRA FROZEN PRESERVED MENISCUS TRANSPLANTATION IN RABBITS

    PubMed Central

    Reckers, Leandro José; Fagundes, Djalma José; Pozo Raymundo, José Luiz; Granata Júnior, Geraldo Sérgio de Mello; Moreira, Márcia Bento; Paiva, Vanessa Carla; Negrini Fagundes, Anna Luiza; Cohen, Moises

    2015-01-01

    Objective: To evaluate the ability of fibrin adhesive in promoting the meniscus fixation within two, four and eight weeks compared to the conventional soft-tissue suture technique. Materials and Methods: 36 right medial menisci of rabbits preserved at negative 73° Celsius for 30 days were transplanted to animals of the same sample and fixed with soft-tissue suture or fibrin glue. After 2, 4 or 8 weeks, the appearance of the menisci and the quality of fixation were macroscopically checked and evaluated by a scoring system. The findings were subjected to the statistical study of variance analysis (p ≤ 0.05%). Results: The deep-frozen meniscus preservation maintained the integrity of the meniscus transplant, and, macroscopically, there was no significant reduction of the length of the meniscus in all post-transplant periods (p = 0.015). The menisci fixed with fibrin showed slight changes in color and surface roughness. There were no signs of rejection or infection in both groups. Suture fixation scoring was superior (p = 0.015) in all periods (80% of total fixation) as compared to the setting promoted by fibrin (20% of total fixation). Conclusion: The homologous transplantation of the meniscus of rabbits experienced various degrees of integration to the knee according to the fixation method; the surgical soft tissues suturing technique was shown to be superior in the evaluation of scores compared to the fixation with fibrin adhesive. PMID:27004186

  17. Cell culture in autologous fibrin scaffolds for applications in tissue engineering.

    PubMed

    de la Puente, Pilar; Ludeña, Dolores

    2014-03-10

    In tissue engineering techniques, three-dimensional scaffolds are needed to adjust and guide cell growth and to allow tissue regeneration. The scaffold must be biocompatible, biodegradable and must benefit the interactions between cells and biomaterial. Some natural biomaterials such as fibrin provide a structure similar to the native extracellular matrix containing the cells. Fibrin was first used as a sealant based on pools of commercial fibrinogen. However, the high risk of viral transmission of these pools led to the development of techniques of viral inactivation and elimination and the use of autologous fibrins. In recent decades, fibrin has been used as a release system and three-dimensional scaffold for cell culture. Fibrin scaffolds have been widely used for the culture of different types of cells, and have found several applications in tissue engineering. The structure and development of scaffolds is a key point for cell culture because scaffolds of autologous fibrin offer an important alternative due to their low fibrinogen concentrations, which are more suitable for cell growth. With this review our aim is to follow methods of development, analyze the commercial and autologous fibrins available and assess the possible applications of cell culture in tissue engineering in these three-dimensional structures.

  18. Optimization of Three Dimensional Culturing of the HepG2 Cell Line in Fibrin Scaffold

    PubMed Central

    Banihashemi, Mehrzad; Mohkam, Milad; Safari, Azam; Nezafat, Navid; Negahdaripour, Manica; Mohammadi, Fatemeh; Kianpour, Sedigheh; Ghasemi, Younes

    2015-01-01

    Background: A potential treatment for healing hepatic tissue is delivering isolated hepatic cells to the site of injury to promote hepatic cells formation. In this technology, providing an appropriate injectable system for delivery of hepatic cells is an important issue. In this regard, fibrin scaffolds were designed with many advantages over other scaffolds like cell delivery vehicles for biodegradation, biocompatibility and hemostasis. Objectives: The aim of this study was to determine suitable cell culture circumstances for HepG2 cell proliferation and differentiation in 3D fibrin scaffolds by evaluating Ca2+ concentrations, cell numbers, various ratios of plasma/RPMI 1640 and thickness of fibrin scaffold. Materials and Methods: In a one-stage experimental design, Box-Behnken design strategy was performed by Minitab 15 software (version 15, Minitab. State College, PA) with three factors at three levels (low, medium and high) and 27 runs for identification of the effects of ratio of plasma/RPMI 1640, Ca2+ concentration and thickness on the formation of fibrin gel scaffold and 3D HepG2 culture. Results: The optimal concentrations for fibrin scaffold fabrication were achieved by adding 0.15 mol CaCl2 (50 µL) and 1 × 105 cells to 1:4 of plasma/RPMI 1640 ratio (500 µL with 2.3 mm thickness per well). Conclusions: Our approach provided easy handle method using inexpensive materials like human plasma instead of purified fibrinogen to fabricate fibrin scaffold. PMID:25861316

  19. Incorporation of exudates of human platelet-rich fibrin gel in biodegradable fibrin scaffolds for tissue engineering of cartilage.

    PubMed

    Chien, Chi-Sheng; Ho, Hsiu-O; Liang, Yu-Chih; Ko, Pai-Hung; Sheu, Ming-Thau; Chen, Chien-Ho

    2012-05-01

    The goal of this study was to assess the incorporation of exudates of human platelet-rich fibrin (hPRF) that is abundant in platelet cytokines and growth factors into biodegradable fibrin (FB) scaffolds as a regeneration matrix for promoting chondrocyte proliferation and re-differentiation. hPRF was obtained from human blood by centrifugation without an anticoagulant, and the exudate of hPRF was collected and mixed with bovine fibrinogen, and then thrombin was added to form the FB scaffold. Proliferation and differentiation of human primary chondrocytes and a human chondrosarcoma cell line, the SW-1353, embedded in the three-dimensional (3D) scaffolds and on the two-dimensional (2D) surface of the FB scaffolds so produced were evaluated in comparison with an agarose (AG) scaffold serving as the control. Results demonstrated that the amounts of these cytokines and growth factors in hPRF exudates were higher than those in the blood-derived products except for TGF-β1. Chondrocytes and SW1353 cells on the 2D and 3D FB scaffolds with the addition of the exudates of PRF exhibited more-available proliferation and differentiation than cells on 2D and 3D FB and AG scaffolds. It was concluded that FB scaffolds can provide an appropriate environment for chondrocyte proliferation and re-differentiation, and it could be improved by adding exudates of hPRF. These 3D scaffolds have great promise for cartilage tissue engineering.

  20. The Viennese culture method: cultured human epithelium obtained on a dermal matrix based on fibroblast containing fibrin glue gels.

    PubMed

    Kamolz, L P; Luegmair, M; Wick, N; Eisenbock, B; Burjak, S; Koller, R; Meissl, G; Frey, M

    2005-02-01

    The aim of this study was to develop a new keratinocyte culture system on a dermal equivalent suitable for skin wound closure. Our dermal matrix is based on a fibrin glue gel containing live human fibroblast (from human foreskin). Keratinocytes obtained from primary culture according to the Rheinwald and Green method, were seeded on to the gel. In all cases, the keratinocytes plated on the dermal equivalent grew to confluence and stratified epithelium was obtained. After 10 days an irregular multilayer could be observed. The cells showed active interaction with the fibrin support, presenting as cell formations projecting into the matrix. After 15 days a regular epithelial sheet consisting of three to four layers of cells was formed. A limiting membrane demarcating the keratinocytes from the fibrin matrix was discernible. Squamous differentiation similar to Strata reticulare and corneum found in vivo could be observed. Nuclei of basal cells were regularly spaced from each other and the chromatin was of homogeneous appearance without prominent nucleoli. The last time point (20 days) showed signs of disintegration of the epithelial sheet. A basement membrane-like structure could not be seen any more. Detachment of the basal cells was associated with subepithelial vacuoles. Basal cells contained irregular nuclei. Therefore, we conclude that 15 days of culture were optimal for the generation of a keratinocyte layers with signs of differentiation; this new culture system could be an important step forward in covering severely burned patients due to a number of advantages, as for example a large expansion factor, the shortening of the optimal culture time to 15 days, the usage of commercially available fibrin glue gels and the versatile manipulation of composite cultures.

  1. The effects of scaffold architecture and fibrin gel addition on tendon cell phenotype.

    PubMed

    Pawelec, K M; Wardale, R J; Best, S M; Cameron, R E

    2015-01-01

    Development of tissue engineering scaffolds relies on careful selection of pore architecture and chemistry of the cellular environment. Repair of skeletal soft tissue, such as tendon, is particularly challenging, since these tissues have a relatively poor healing response. When removed from their native environment, tendon cells (tenocytes) lose their characteristic morphology and the expression of phenotypic markers. To stimulate tendon cells to recreate a healthy extracellular matrix, both architectural cues and fibrin gels have been used in the past, however, their relative effects have not been studied systematically. Within this study, a combination of collagen scaffold architecture, axial and isotropic, and fibrin gel addition was assessed, using ovine tendon-derived cells to determine the optimal strategy for controlling the proliferation and protein expression. Scaffold architecture and fibrin gel addition influenced tendon cell behavior independently in vitro. Addition of fibrin gel within a scaffold doubled cell number and increased matrix production for all architectures studied. However, scaffold architecture dictated the type of matrix produced by cells, regardless of fibrin addition. Axial scaffolds, mimicking native tendon, promoted a mature matrix, with increased tenomodulin, a marker for mature tendon cells, and decreased scleraxis, an early transcription factor for connective tissue. This study demonstrated that both architectural cues and fibrin gel addition alter cell behavior and that the combination of these signals could improve clinical performance of current tissue engineering constructs.

  2. Optimization and Use of 3D sintered porous material in medical field for mixing fibrin glue.

    NASA Astrophysics Data System (ADS)

    Delmotte, Y.; Laroumanie, H.; Brossard, G.

    2012-04-01

    In medical field, Mixing of two or more chemical components (liquids and/or gases) is extremely important as improper mixing can affect the physico-chemical properties of the final product. At Baxter Healthcare Corporation, we are using a sintered porous material (PM) as a micro-mixer in medical device for mixing Fibrinogen and Thrombin in order to obtain a homogeneous polymerized Fibrin glue clot used in surgery. First trials were carried out with an interconnected PM from Porvair® (made of PE - porosity: 40% - permeability: 18Darcy). The injection rate is very low, usually about 10mL/min (Re number about 50) which keeps fluids in a laminar flow. Such a low flow rate does not favour mixing of fluids having gradient of viscosity if a mixer is not used. Promising results that were obtained lead the team to understand this ability to mix fluids which will be presented in the poster. Topology of porous media (PM) which associates a solid phase with interconnected (or not) porous structure is known and used in many commodity products. Researches on PM usually focus on flows inside this structure. By opposition to transport and filtration capacity, as well as mechanic and thermic properties, mixing is rarely associated with PM. However over the past few years, we shown that some type of PM have a real capacity to mix certain fluids. Poster will also describe the problematic of mixing complex biological fluids as fibrinogen and Thrombin. They indeed present a large viscosity difference (ratio about 120) limiting the diffusion and the interaction between the two solutions. As those products are expensive, we used Water (1cPo) and Glycerol 87% (120cPo) which are matching the viscosities of Thrombin and Fibrinogen. A parametric investigation of the "porous micro-mixer" as well as a scale up investigation was carried out to examine the influence of both diffusion and advection to successful mix fluids of different viscosity. Experiments were implemented with Planar Laser

  3. Fabrication of fibrin based electrospun multiscale composite scaffold for tissue engineering applications.

    PubMed

    Sreerekha, P R; Menon, Deepthy; Nair, S V; Chennazhi, K P

    2013-05-01

    Fabricating scaffolds mimicking the native extracellular matrix (ECM) in both structure and function is a key challenge in the field of tissue engineering. Previously we have demonstrated a novel electrospinnig method for the fabrication of fibrin nanofibers using Poly(vinyl alcohol) (PVA) as an 'electrospinning-driving' polymer. Here we demonstrate the fabrication and characterization of a multiscale fibrin based composite scaffold with polycaprolactone (PCL) by sequential electrospinning of PCL microfibers and fibrin nanofibers. This multiscale scaffold has great potential for tissue engineering applications due to the combined benefits of biological nanofibers such as cell attachment and proliferation and that of microfibers such as open structure, larger pore size and adequate mechanical strength. Physico chemical characterization of the electrospun scaffold was done by Scanning Electron Microscopy (SEM), Contact angle analysis, fibrin specific Phosphotungstic acid haematoxyllin (PTAH) staining and evaluation of mechanical properties. SEM data revealed the formation of bead free nanofibers of fibrin with a fiber diameter ranging from 50-500 nm and microfibers of PCL in the size range of 1 microns to 2.5 microns. These dimensions mimic the hierarchical structure of ECM found in native tissues. Cell attachment and viability studies using human mesenchymal stem cells (hMSC) revealed that the scaffold is non toxic and supports cell attachment, spreading and proliferation. In addition, we examined the inflammatory potential of the scaffold to demonstrate its usefulness in tissue engineering applications.

  4. Effect of Fibrin Glue on the Incidence of Surgical Complications After Living-Related-Donor Kidney Transplantation: Results of a Randomized Clinical Trial.

    PubMed

    Fuentes-Orozco, Clotilde; González-Mercado, Salvador; Sandoval-Sandoval, Joel Mario; Valdespino-Mejía, Carlos; González-González, Eduardo; Ramírez-Robles, Juan Narciso; Gómez-Navarro, Benjamín; Dávalos-Delgadillo, Blanca Estela; Marquez-Leaño, Leticia; Ramírez-Arce, Anais; Andalón-Dueñas, Elizabeth; Espinosa-Partida, Arturo; Macías-Amezcua, Michel Dassaejv; González-Ojeda, Alejandro

    2016-01-01

    BACKGROUND The incidence of surgical complications after kidney transplantation ranges from 10-25%. The purpose of this study was to evaluate if the application of fibrin glue as a preventive agent reduces surgical morbidity after a living-related-donor kidney transplantation. MATERIAL AND METHODS A controlled clinical trial involving 78 recipients randomly assigned to receive fibrin glue and 79 in the control group without the application of fibrin glue. Patients were followed for six months after surgery. RESULTS The average ages were 24.8±9.4 and 27.4±11.3 years in the control and study groups, respectively (p=0.11). Individual morbidities, such as urologic, lymphatic, vascular, and wound complications, were not statistically different between groups; however, the total number of surgical complications observed were in five patients in the study group and 16 patients in the control group. This difference was statistically significant (p<0.01, relative risk 0.44, 95% CI 0.20-0.97). There was no mortality or adverse reaction to fibrin glue. One kidney graft was lost because of uncontrollable bleeding secondary to tearing of the renal capsule. The incidence of early medical complications was similar between groups. CONCLUSIONS Applications of the biological adhesive reduced the incidence of surgical complications. PMID:27646850

  5. Fibrin glue fixation of a digital osteochondral fracture: case report and review of the literature.

    PubMed

    Shah, Munir A; Ebert, Andrew M; Sanders, William E

    2002-05-01

    Surgical treatment options for digital osteochondral fractures are limited by the small amount of bone available for fixation and the propensity for digital stiffness with the introduction of hardware. Fibrin sealant is used in a variety of clinical settings as a biologic bonding agent and may circumvent the drawbacks of traditional fixation or simple excision for certain digital osteochondral injuries. Successful use of fibrin sealant fixation for a patient with an osteochondral fracture involving the proximal interphalangeal joint is documented, and the literature on fibrin sealant for osseous fixation is reviewed.

  6. A new fibrin sealant as a three-dimensional scaffold candidate for mesenchymal stem cells

    PubMed Central

    2014-01-01

    Introduction The optimization of an organic scaffold for specific types of applications and cells is vital to successful tissue engineering. In this study, we investigated the effects of a new fibrin sealant derived from snake venom as a scaffold for mesenchymal stem cells, to demonstrate the ability of cells to affect and detect the biological microenvironment. Methods The characterization of CD34, CD44 and CD90 expression on mesenchymal stem cells was performed by flow cytometry. In vitro growth and cell viability were evaluated by light and electron microscopy. Differentiation into osteogenic, adipogenic and chondrogenic lineages was induced. Results The fibrin sealant did not affect cell adhesion, proliferation or differentiation and allowed the adherence and growth of mesenchymal stem cells on its surface. Hoechst 33342 and propidium iodide staining demonstrated the viability of mesenchymal stem cells in contact with the fibrin sealant and the ability of the biomaterial to maintain cell survival. Conclusions The new fibrin sealant is a three-dimensional scaffolding candidate that is capable of maintaining cell survival without interfering with differentiation, and might also be useful in drug delivery. Fibrin sealant has a low production cost, does not transmit infectious diseases from human blood and has properties of a suitable scaffold for stem cells because it permits the preparation of differentiated scaffolds that are suitable for every need. PMID:24916098

  7. Comparison between self-assembling peptide nanofiber scaffold (SAPNS) and fibrin sealant in neurosurgical hemostasis.

    PubMed

    Xu, Fei-Fan; Wang, Yue-Chun; Sun, Stella; Ho, Amy S W; Lee, Derek; Kiang, Karrie M Y; Zhang, Xiao-Qin; Lui, Wai-Man; Liu, Bai-Yun; Wu, Wu-Tian; Leung, Gilberto K K

    2015-10-01

    RADA16-I is a synthetic type I self-assembling peptide nanofiber scaffold (SAPNS) which may serve as a novel biocompatible hemostatic agent. Its application in neurosurgical hemostasis, however, has not been explored. Although RADA16-I is nontoxic and nonimmunogenic, its intrinsic acidity may potentially provoke inflammation in the surgically injured brain. We conducted an animal study to compare RADA16-I with fibrin sealant, a commonly used agent, with the hypothesis that the former would be a comparable alternative. Using a standardized surgical brain injury model, 30 Sprague-Dawley rats were randomized into three treatment groups: RADA16-I, fibrin sealant or gelatin sponge (control). Animals were sacrificed on day 3 and 42. Astrocytic and microglial infiltrations within the cerebral parenchyma adjacent to the operative site were significantly lower in the RADA16-I and fibrin sealant groups than control. RADA16-I did not cause more cellular inflammatory response despite its acidity when compared with fibrin sealant. Immunohistochemical studies showed infiltration by astrocytes and microglia into the fibrin sealant and RADA16-I grafts, suggesting their potential uses as tissue scaffolds. RADA16-I is a promising candidate for further translational and clinical studies that focus on its applications as a safe and effective hemostat, proregenerative nanofiber scaffold as well as drug and cell carrier. PMID:26077376

  8. Free-electron laser effects on fibrin tissue glue: a preliminary study

    NASA Astrophysics Data System (ADS)

    Joos, Karen M.; Topadze, Katie; Shieh, Charles; Shen, Jin-Hui; Casagrande, Vivien A.

    2000-06-01

    One glaucoma challenge is the treatment of leaking trabeculectomy blebs. Simple methods such as patching, autologous blood injection, compression sutures or cyanoacrylate glue application often fail. Because the conjunctiva is thin and ischemic, it often can't be sutured together so major surgery is required to excise the thin tissue and advance healthy conjunctiva. We report the preliminary results of Tisseel and Tisseel treated with two wavelengths from Vanderbilt's free electron laser placed on leaking trabeculectomy bleb holes in Dutch belted rabbits. The holes were healed at one week in the sutured group and in the 7.7 micrometer FEL-treated Tisseel group. One hole was healed in the cyanoacrylate glue-treated group. Holes remained in the other treatment groups. Tisseel irradiated with 7.7 micrometer energy from the free electron laser may promote healing of trabeculectomy bleb holes.

  9. The Effect of Bone Marrow-Derived Mesenchymal Stem Cells and Their Conditioned Media Topically Delivered in Fibrin Glue on Chronic Wound Healing in Rats.

    PubMed

    Mehanna, Radwa A; Nabil, Iman; Attia, Noha; Bary, Amany A; Razek, Khalid A; Ahmed, Tamer A E; Elsayed, Fatma

    2015-01-01

    Bone marrow-derived mesenchymal stem cells (BM-MSCs) represent a modern approach for management of chronic skin injuries. In this work, we describe BM-MSCs application versus their conditioned media (CM) when delivered topically admixed with fibrin glue to enhance the healing of chronic excisional wounds in rats. Fifty-two adult male rats were classified into four groups after induction of large-sized full-thickness skin wound: control group (CG), fibrin only group (FG), fibrin + MSCs group (FG + SCs), and fibrin + CM group (FG + CM). Healing wounds were evaluated functionally and microscopically. Eight days after injury, number of CD68+ macrophages infiltrating granulation tissue was considerably higher in the latter two groups. Although--later--none of the groups depicted a substantially different healing rate, the quality of regenerated skin was significantly boosted by the application of either BM-MSCs or their CM both (1) structurally as demonstrated by the obviously increased mean area percent of collagen fibers in Masson's trichrome-stained skin biopsies and (2) functionally as supported by the interestingly improved epidermal barrier as well as dermal tensile strength. Thus, we conclude that topically applied BM-MSCs and their CM-via fibrin vehicle--could effectively improve the quality of healed skin in chronic excisional wounds in rats, albeit without true acceleration of wound closure.

  10. The Effect of Bone Marrow-Derived Mesenchymal Stem Cells and Their Conditioned Media Topically Delivered in Fibrin Glue on Chronic Wound Healing in Rats

    PubMed Central

    Mehanna, Radwa A.; Nabil, Iman; Attia, Noha; Bary, Amany A.; Razek, Khalid A.; Ahmed, Tamer A. E.; Elsayed, Fatma

    2015-01-01

    Bone marrow-derived mesenchymal stem cells (BM-MSCs) represent a modern approach for management of chronic skin injuries. In this work, we describe BM-MSCs application versus their conditioned media (CM) when delivered topically admixed with fibrin glue to enhance the healing of chronic excisional wounds in rats. Fifty-two adult male rats were classified into four groups after induction of large-sized full-thickness skin wound: control group (CG), fibrin only group (FG), fibrin + MSCs group (FG + SCs), and fibrin + CM group (FG + CM). Healing wounds were evaluated functionally and microscopically. Eight days after injury, number of CD68+ macrophages infiltrating granulation tissue was considerably higher in the latter two groups. Although—later—none of the groups depicted a substantially different healing rate, the quality of regenerated skin was significantly boosted by the application of either BM-MSCs or their CM both (1) structurally as demonstrated by the obviously increased mean area percent of collagen fibers in Masson's trichrome-stained skin biopsies and (2) functionally as supported by the interestingly improved epidermal barrier as well as dermal tensile strength. Thus, we conclude that topically applied BM-MSCs and their CM—via fibrin vehicle—could effectively improve the quality of healed skin in chronic excisional wounds in rats, albeit without true acceleration of wound closure. PMID:26236740

  11. Comprehensive evaluation of fibrin glue as a local drug-delivery system-efficacy and safety of sustained release of vancomycin by fibrin glue against local methicillin-resistant Staphylococcus aureus infection.

    PubMed

    Ozaki, Shinichi; Saito, Aya; Nakaminami, Hidemasa; Ono, Minoru; Noguchi, Norihisa; Motomura, Noboru

    2014-03-01

    Infection of prosthetic grafts, especially with methicillin-resistant Staphylococcus aureus (MRSA), often becomes critical. Although topical administration of antibiotics has been applied empirically, no comprehensive data are available showing long-lasting effects and safety of local antibiotic usage. By means of animal experiments we assessed fibrin glue (FG) as a slow-release vehicle for vancomycin (VCM) against local MRSA infection. Preliminary in-vitro experiments were performed to confirm that the FG-VCM mixture maintained viscosity as a sealant and led to slow-release of VCM. We next created a subcutaneous pocket in a rodent back and implanted a 1 cm (2) woven graft with 1 ml FG alone, or with serial concentrations of VCM (0-120 mg/ml. n = 3 for each group). MRSA of 1 × 10(7) colony-forming units (CFU) was injected into the pocket after wound closure. The graft was explanted 7 days later and was submitted for culture ("Culture-graft"). Blood samples were obtained for regular blood work, serum VCM concentration measurements, and blood culture ("Culture-blood"). The pocket tissue was also submitted for measurement of local VCM concentration. There was a remarkable infectious response in the group without vancomycin; however, no other groups developed any sign of infection. "Culture-graft" resulted in MRSA growth for V0 only. "Culture-blood" was negative in all groups, and only minimal serum concentrations of vancomycin were detected. One-dose topical administration of VCM via FG was effective against localized MRSA graft infection without systemic VCM administration. Topical administration of antibiotics may help treat difficult graft infections and reduce systemic use of potent antibiotics.

  12. Effect of platelet-rich plasma and fibrin glue on healing of critical-size calvarial bone defects.

    PubMed

    Findikcioglu, Kemal; Findikcioglu, Fulya; Yavuzer, Reha; Elmas, Cigdem; Atabay, Kenan

    2009-01-01

    Despite the insufficient number of experimental studies, platelet-rich plasma (PRP) including high amounts of growth factors is introduced to clinical use rapidly. The aim of this study was to compare the effects of PRP and platelet-poor plasma (PPP) on healing of critical-size bone defects.Bilateral full-thickness, critical-size bone defects were created in the parietal bones of 32 rabbits, which had been studied in 4 groups. Saline, thrombin solution, PPP, and PRP were applied to the created defects before closure. Radiologic defect area measurement results at 0, 4, and 16 weeks were compared between the groups. In addition, densities of the newly formed bones at 16th week were studied. Histologic parameters (primary and secondary bone trabecula, neovascularization, and bone marrow and connective tissue formation) were compared between 4- and 16-week groups.More rapid decrease in defect size was observed in groups 3 and 4 than in groups 1 and 2, both in the 4th and 16th weeks. Newly formed bone densities were also found to be higher in these 2 groups. New bone formation was detected to be more rapid considering histologic parameters, in groups 3 and 4 at 4th and 16th weeks.Study demonstrates that PRP and PPP might have favorable effects on bone healing. Although we cannot reveal any statistical difference between these 2 substances considering osteoinductive potential, PRP group has demonstrated superior results compared with fibrin glue group. Higher platelet concentrations may expose beneficial effects of PRP.

  13. Engineering personalized neural tissue by combining induced pluripotent stem cells with fibrin scaffolds.

    PubMed

    Montgomery, Amy; Wong, Alix; Gabers, Nicole; Willerth, Stephanie M

    2015-02-01

    Induced pluripotent stem cells (iPSCs) are generated from adult somatic cells through the induction of key transcription factors that restore the ability to become any cell type found in the body. These cells are of interest for tissue engineering due to their potential for developing patient-specific therapies. As the technology for generating iPSCs advances, it is important to concurrently investigate protocols for the efficient differentiation of these cells to desired downstream phenotypes in combination with biomaterial scaffolds as a way of engineering neural tissue. For such applications, the generation of neurons within three dimensional fibrin scaffolds has been well characterized as a cell-delivery platform for murine embryonic stem cells (ESCs) but has not yet been applied to murine iPSCs. Given that iPSCs have been reported to differentiate less effectively than ESCs, a key objective of this investigation is to maximize the proportion of iPSC-derived neurons in fibrin through the choice of differentiation protocol. To this end, this study compares two EB-mediated protocols for generating neurons from murine iPSCs and ESCs: an 8 day 4-/4+ protocol using soluble retinoic acid in the last 4 days and a 6 day 2-/4+ protocol using soluble retinoic acid and the small molecule sonic hedgehog agonist purmorphamine in the last 4 days. EBs were then seeded in fibrin scaffolds for 14 days to allow further differentiation into neurons. EBs generated by the 2-/4+ protocol yielded a higher percentage of neurons compared to those from the 4-/4+ protocol for both iPSCs and ESCs. The results demonstrate the successful translation of the fibrin-based cell-delivery platform for use with murine iPSCs and furthermore that the proportion of neurons generated from murine iPSC-derived EBs seeded in fibrin can be maximized using the 2-/4+ differentiation protocol. Together, these findings validate the further exploration of 3D fibrin-based scaffolds as a method of delivering

  14. Preparation of 3D fibrin scaffolds for stem cell culture applications.

    PubMed

    Kolehmainen, Kathleen; Willerth, Stephanie M

    2012-01-01

    Stem cells are found in naturally occurring 3D microenvironments in vivo, which are often referred to as the stem cell niche. Culturing stem cells inside of 3D biomaterial scaffolds provides a way to accurately mimic these microenvironments, providing an advantage over traditional 2D culture methods using polystyrene as well as a method for engineering replacement tissues. While 2D tissue culture polystrene has been used for the majority of cell culture experiments, 3D biomaterial scaffolds can more closely replicate the microenvironments found in vivo by enabling more accurate establishment of cell polarity in the environment and possessing biochemical and mechanical properties similar to soft tissue. A variety of naturally derived and synthetic biomaterial scaffolds have been investigated as 3D environments for supporting stem cell growth. While synthetic scaffolds can be synthesized to have a greater range of mechanical and chemical properties and often have greater reproducibility, natural biomaterials are often composed of proteins and polysaccharides found in the extracelluar matrix and as a result contain binding sites for cell adhesion and readily support cell culture. Fibrin scaffolds, produced by polymerizing the protein fibrinogen obtained from plasma, have been widely investigated for a variety of tissue engineering applications both in vitro and in vivo. Such scaffolds can be modified using a variety of methods to incorporate controlled release systems for delivering therapeutic factors. Previous work has shown that such scaffolds can be used to successfully culture embryonic stem cells and this scaffold-based culture system can be used to screen the effects of various growth factors on the differentiation of the stem cells seeded inside. This protocol details the process of polymerizing fibrin scaffolds from fibrinogen solutions using the enzymatic activity of thrombin. The process takes 2 days to complete, including an overnight dialysis step for the

  15. Preparation of 3D Fibrin Scaffolds for Stem Cell Culture Applications

    PubMed Central

    Kolehmainen, Kathleen; Willerth, Stephanie M.

    2012-01-01

    Stem cells are found in naturally occurring 3D microenvironments in vivo, which are often referred to as the stem cell niche 1. Culturing stem cells inside of 3D biomaterial scaffolds provides a way to accurately mimic these microenvironments, providing an advantage over traditional 2D culture methods using polystyrene as well as a method for engineering replacement tissues 2. While 2D tissue culture polystrene has been used for the majority of cell culture experiments, 3D biomaterial scaffolds can more closely replicate the microenvironments found in vivo by enabling more accurate establishment of cell polarity in the environment and possessing biochemical and mechanical properties similar to soft tissue.3 A variety of naturally derived and synthetic biomaterial scaffolds have been investigated as 3D environments for supporting stem cell growth. While synthetic scaffolds can be synthesized to have a greater range of mechanical and chemical properties and often have greater reproducibility, natural biomaterials are often composed of proteins and polysaccharides found in the extracelluar matrix and as a result contain binding sites for cell adhesion and readily support cell culture. Fibrin scaffolds, produced by polymerizing the protein fibrinogen obtained from plasma, have been widely investigated for a variety of tissue engineering applications both in vitro and in vivo4. Such scaffolds can be modified using a variety of methods to incorporate controlled release systems for delivering therapeutic factors 5. Previous work has shown that such scaffolds can be used to successfully culture embryonic stem cells and this scaffold-based culture system can be used to screen the effects of various growth factors on the differentiation of the stem cells seeded inside 6,7. This protocol details the process of polymerizing fibrin scaffolds from fibrinogen solutions using the enzymatic activity of thrombin. The process takes 2 days to complete, including an overnight dialysis

  16. A new heterologous fibrin sealant as a scaffold to cartilage repair-Experimental study and preliminary results.

    PubMed

    de Barros, Caio Nunes; Miluzzi Yamada, Ana Lúcia; Junior, Rui Seabra F; Barraviera, Benedito; Hussni, Carlos Alberto; de Souza, Jaqueline Brandão; Watanabe, Marcos Jun; Rodrigues, Celso Antônio; Garcia Alves, Ana Liz

    2016-07-01

    Autologous fibrin gel is commonly used as a scaffold for filling defects in articular cartilage. This biomaterial can also be used as a sealant to control small hemorrhages and is especially helpful in situations where tissue reparation capacity is limited. In particular, fibrin can act as a scaffold for various cell types because it can accommodate cell migration, differentiation, and proliferation. Despite knowledge of the advantages of this biomaterial and mastery of the techniques required for its application, the durability of several types of sealant at the site of injury remains questionable. Due to the importance of such data for evaluating the quality and efficiency of fibrin gel formulations on its use as a scaffold, this study sought to analyze the heterologous fibrin sealant developed from the venom of Crotalus durissus terrificus using studies in ovine experimental models. The fibrin gel developed from the venom of this snake was shown to act as a safe, stable, and durable scaffold for up to seven days, without causing adverse side effects. Fibrin gel produced from the venom of the Crotalus durissus terrificus snake possesses many clinical and surgical uses. It presents the potential to be used as a biomaterial to help repair skin lesions or control bleeding, and it may also be used as a scaffold when applied together with various cell types. The intralesional use of the fibrin gel from the venom of this snake may improve surgical and clinical treatments in addition to being inexpensive and adequately consistent, durable, and stable. The new heterologous fibrin sealant is a scaffold candidate to cartilage repair in this study.

  17. Mini-open transthoracic approach for resection of a calcified herniated thoracic disc and repair of the dural surface with fibrin glue: a case report.

    PubMed

    Yoshioka, Katsuhito; Murakami, Hideki; Demura, Satoru; Kato, Satoshi; Tsuchiya, Hiroyuki

    2015-08-01

    This study reports a case of severe anterior compression of the spinal cord by a calcified herniated thoracic disc at the T9/10 level in a 46-year-old woman. She underwent resection of the calcified herniated thoracic disc and the integrated dura, using a microscopically assisted mini-open transthoracic approach. The remaining dura mater was shaped and repaired by alternate overlapping without suture. The dural surface was reinforced with a combination of fibrin glue and a polyglycolic acid sheet. This novel procedure prevented postoperative cerebrospinal fluid leakage. The patient made an excellent recovery, without any complications. PMID:26321561

  18. Treatment of life-threatening wounds with a combination of allogenic platelet-rich plasma, fibrin glue and collagen matrix, and a literature review.

    PubMed

    Asadi, Mehdi; Alamdari, Daryoush Hamidi; Rahimi, Hamid Reza; Aliakbarian, Mohsen; Jangjoo, Ali; Abdollahi, Abbas; Bahar, Mostafa Mehrabi; Azadmand, Ali; Forghani, Naser; Sadegh, Mohammad Nori; Khayamy, Mohammad Esmail; Seifalian, Alexander

    2014-08-01

    Currently there is no ideal procedure for the treatment of recalcitrant ulcers that are unresponsive to the majority of common treatments. However, several novel approaches have been proposed, including bone marrow stem cells, platelets, fibrin glue and collagen matrix. For the first approach treatment of a chronic wound, a non-invasive method is highly desirable. The present study was undertaken with the aim of evaluating the effect of a combination of platelets, fibrin glue and collagen matrix (PFC) in one treatment. A total of ten patients with aggressive, refractory, life-threatening wounds were recruited for the study and their treatment effects were evaluated. Initially, the ulcers were extensively debrided, measured and photographed at weekly intervals. The PFC combination was applied topically to the wound every two days. Following treatment, the wound was completely closed in nine patients and was markedly reduced in the other patient. The mean 100% healing time for the nine patients was 11.3±5.22 weeks. There was no evidence of local or systemic complications or any abnormal tissue formation, keloid or hypertrophic scarring. Therefore, the results of the present study indicate that in the first approach, the combination of PFC components may be used safely in order to synergize the effect of chronic wound healing.

  19. Treatment of life-threatening wounds with a combination of allogenic platelet-rich plasma, fibrin glue and collagen matrix, and a literature review

    PubMed Central

    ASADI, MEHDI; ALAMDARI, DARYOUSH HAMIDI; RAHIMI, HAMID REZA; ALIAKBARIAN, MOHSEN; JANGJOO, ALI; ABDOLLAHI, ABBAS; BAHAR, MOSTAFA MEHRABI; AZADMAND, ALI; FORGHANI, NASER; SADEGH, MOHAMMAD NORI; KHAYAMY, MOHAMMAD ESMAIL; SEIFALIAN, ALEXANDER

    2014-01-01

    Currently there is no ideal procedure for the treatment of recalcitrant ulcers that are unresponsive to the majority of common treatments. However, several novel approaches have been proposed, including bone marrow stem cells, platelets, fibrin glue and collagen matrix. For the first approach treatment of a chronic wound, a non-invasive method is highly desirable. The present study was undertaken with the aim of evaluating the effect of a combination of platelets, fibrin glue and collagen matrix (PFC) in one treatment. A total of ten patients with aggressive, refractory, life-threatening wounds were recruited for the study and their treatment effects were evaluated. Initially, the ulcers were extensively debrided, measured and photographed at weekly intervals. The PFC combination was applied topically to the wound every two days. Following treatment, the wound was completely closed in nine patients and was markedly reduced in the other patient. The mean 100% healing time for the nine patients was 11.3±5.22 weeks. There was no evidence of local or systemic complications or any abnormal tissue formation, keloid or hypertrophic scarring. Therefore, the results of the present study indicate that in the first approach, the combination of PFC components may be used safely in order to synergize the effect of chronic wound healing. PMID:25009595

  20. Differentiation within autologous fibrin scaffolds of porcine dermal cells with the mesenchymal stem cell phenotype

    SciTech Connect

    Puente, Pilar de la

    2013-02-01

    Porcine mesenchymal stem cells (pMSCs) are an attractive source of cells for tissue engineering because their properties are similar to those of human stem cells. pMSCs can be found in different tissues but their dermal origin has not been studied in depth. Additionally, MSCs differentiation in monolayer cultures requires subcultured cells, and these cells are at risk of dedifferentiation when implanting them into living tissue. Following this, we attempted to characterize the MSCs phenotype of porcine dermal cells and to evaluate their cellular proliferation and differentiation in autologous fibrin scaffolds (AFSs). Dermal biopsies and blood samples were obtained from 12 pigs. Dermal cells were characterized by flow cytometry. Frozen autologous plasma was used to prepare AFSs. pMSC differentiation was studied in standard structures (monolayers and pellets) and in AFSs. The pMSCs expressed the CD90 and CD29 markers of the mesenchymal lineage. AFSs afforded adipogenic, osteogenic and chondrogenic differentiation. The porcine dermis can be proposed to be a good source of MSCs with adequate proliferative capacity and a suitable expression of markers. The pMSCs also showed optimal proliferation and differentiation in AFSs, such that these might serve as a promising autologous and implantable material for use in tissue engineering. -- Highlights: ► Low fibrinogen concentration provides a suitable matrix for cell migration and differentiation. ► Autologous fibrin scaffolds is a promising technique in tissue engineering. ► Dermal cells are an easily accessible mesenchymal stem cell source. ► Fibrin scaffolds afforded adipogenic, osteogenic and chondrogenic differentiation.

  1. Recombinant human bone morphogenetic protein-2 suspended in fibrin glue enhances bone formation during distraction osteogenesis in rabbits

    PubMed Central

    Li, Yunfeng; Li, Rui; Hu, Jing; Song, Donghui; Jiang, Xiaowen

    2016-01-01

    Introduction Bone morphogenetic protein-2 (BMP-2) has high potential for bone formation, but its in vivo effects are unpredictable due to the short life time. This study was designed to evaluate the effects of recombinant human (rh) BMP-2 suspended in fibrin on bone formation during distraction osteogenesis (DO) in rabbits. Material and methods The in vitro release kinetics of rhBMP-2 suspended in fibrin was tested using an enzyme-linked immunosorbent assay. Unilateral tibial lengthening for 10 mm was achieved in 48 rabbits. At the completion of osteodistraction, vehicle, fibrin, rhBMP-2 or rhBMP-2 suspended in fibrin (rhBMP-2 + fibrin) was injected into the center of the lengthened gap, with 12 animals in each group. Eight weeks later, the distracted callus was examined by histology, micro-CT and biomechanical testing. Radiographs of the distracted tibiae were taken at both 4 and 8 weeks after drug treatment. Results It was found that fibrin prolonged the life span of rhBMP-2 in vitro with sustained release during 17 days. The rhBMP-2 + fibrin treated animals showed the best results in bone mineral density, bone volume fraction, cortical bone thickness by micro-CT evaluation and mechanical properties by the three-point bending test when compared to the other groups (p < 0.05). In histological images, rhBMP-2 + fibrin treatment showed increased callus formation and better gap bridging compared to the other groups. Conclusions The results of this study suggest that fibrin holds promise to be a good carrier of rhBMP-2, and rhBMP-2 suspended in fibrin showed a stronger promoting effect on bone formation during DO in rabbits. PMID:27279839

  2. Autologous fibrin scaffolds cultured dermal fibroblasts and enriched with encapsulated bFGF for tissue engineering.

    PubMed

    de la Puente, Pilar; Ludeña, Dolores; Fernández, Ana; Aranda, Jose L; Varela, Gonzalo; Iglesias, Javier

    2011-12-15

    Autologous fibrin scaffolds (AFSs) enriched with cells and specific growth factors represent a promising biocompatible scaffold for tissue engineering. Here, we analyzed the in vitro behavior of dermal fibroblasts (DFs) (cellular attachment, distribution, viability and proliferation, histological and immunohistochemical changes), comparing AFS with and without alginate microcapsules loaded with basic fibroblast growth factor (bFGF), to validate our scaffold in a future animal model in vivo. In all cases, DFs showed good adhesion and normal distribution, while in scaffolds with bFGF at 14 days, the cell counts detected in proliferation and viability assays were greatly improved, as was the proliferative state, and there was a decrease in muscle specific actin expression and collagen synthesis in comparison with the scaffolds without bFGF. In addition, the use of plasma without fibrinogen concentration methods, together with the maximum controlled release of bFGF at 14 days, favored cell proliferation. To conclude, we have been able to create an AFS enriched with fully functional DFs and release-controlled bFGF that could be used in multiple applications for tissue engineering.

  3. Novel magnetic fibrin hydrogel scaffolds containing thrombin and growth factors conjugated iron oxide nanoparticles for tissue engineering

    PubMed Central

    Ziv-Polat, Ofra; Skaat, Hadas; Shahar, Abraham; Margel, Shlomo

    2012-01-01

    Novel tissue-engineered magnetic fibrin hydrogel scaffolds were prepared by the interaction of thrombin-conjugated iron oxide magnetic nanoparticles with fibrinogen. In addition, stabilization of basal fibroblast growth factor (bFGF) was achieved by the covalent and physical conjugation of the growth factor to the magnetic nanoparticles. Adult nasal olfactory mucosa (NOM) cells were seeded in the transparent fibrin scaffolds in the absence or presence of the free or conjugated bFGF-iron oxide nanoparticles. The conjugated bFGF enhanced significantly the growth and differentiation of the NOM cells in the fibrin scaffolds, compared to the same or even five times higher concentration of the free bFGF. In the presence of the bFGF-conjugated magnetic nanoparticles, the cultured NOM cells proliferated and formed a three-dimensional interconnected network composed mainly of tapered bipolar cells. The magnetic properties of these matrices are due to the integration of the thrombin- and bFGF-conjugated magnetic nanoparticles within the scaffolds. The magnetic properties of these scaffolds may be used in future work for various applications, such as magnetic resonance visualization of the scaffolds after implantation and reloading the scaffolds via magnetic forces with bioactive agents, eg, growth factors bound to the iron oxide magnetic nanoparticles. PMID:22419873

  4. Bio-printing of collagen and VEGF-releasing fibrin gel scaffolds for neural stem cell culture.

    PubMed

    Lee, Yeong-Bae; Polio, Samuel; Lee, Wonhye; Dai, Guohao; Menon, Lata; Carroll, Rona S; Yoo, Seung-Schik

    2010-06-01

    Time-released delivery of soluble growth factors (GFs) in engineered hydrogel tissue constructs promotes the migration and proliferation of embedded cells, which is an important factor for designing scaffolds that ultimately aim for neural tissue regeneration. We report a tissue engineering technique to print murine neural stem cells (C17.2), collagen hydrogel, and GF (vascular endothelial growth factor: VEGF)-releasing fibrin gel to construct an artificial neural tissue. We examined the morphological changes of the printed C17.2 cells embedded in the collagen and its migration toward the fibrin gel. The cells showed high viability (92.89+/-2.32%) after printing, which was equivalent to that of manually-plated cells. C17.2 cells printed within 1mm from the border of VEGF-releasing fibrin gel showed GF-induced changes in their morphology. The cells printed in this range also migrated toward the fibrin gel, with the total migration distance of 102.4+/-76.1microm over 3days. The cells in the control samples (fibrin without the VEGF or VEGF printed directly in collagen) neither proliferated nor migrated. The results demonstrated that bio-printing of VEGF-containing fibrin gel supported sustained release of the GF in the collagen scaffold. The presented method can be gainfully used in the development of three-dimensional (3D) artificial tissue assays and neural tissue regeneration applications. PMID:20211178

  5. Design and Characterization of Fibrin-Based Acoustically Responsive Scaffolds for Tissue Engineering Applications.

    PubMed

    Moncion, Alexander; Arlotta, Keith J; Kripfgans, Oliver D; Fowlkes, J Brian; Carson, Paul L; Putnam, Andrew J; Franceschi, Renny T; Fabiilli, Mario L

    2016-01-01

    Hydrogel scaffolds are used in tissue engineering as a delivery vehicle for regenerative growth factors. Spatiotemporal patterns of growth factor signaling are critical for tissue regeneration, yet most scaffolds afford limited control of growth factor release, especially after implantation. We previously found that acoustic droplet vaporization can control growth factor release from a fibrin scaffold doped with a perfluorocarbon emulsion. This study investigates properties of the acoustically responsive scaffold (ARS) critical for further translation. At 2.5 MHz, acoustic droplet vaporization and inertial cavitation thresholds ranged from 1.5 to 3.0 MPa and from 2.0 to 7.0 MPa peak rarefactional pressure, respectively, for ARSs of varying composition. Viability of C3H/10T1/2 cells, encapsulated in the ARS, did not decrease significantly for pressures below 4 MPa. ARSs with perfluorohexane emulsions displayed higher stability versus those with perfluoropentane emulsions, while surrogate payload release was minimal without ultrasound. These results enable the selection of ARS compositions and acoustic parameters needed for optimized spatiotemporally controlled release.

  6. The Effect of Sterilization Methods on the Structural and Chemical Properties of Fibrin Microthread Scaffolds.

    PubMed

    Grasman, Jonathan M; O'Brien, Megan P; Ackerman, Kevin; Gagnon, Keith A; Wong, Gregory M; Pins, George D

    2016-06-01

    A challenge for the design of scaffolds in tissue engineering is to determine a terminal sterilization method that will retain the structural and biochemical properties of the materials. Since commonly used heat and ionizing energy-based sterilization methods have been shown to alter the material properties of protein-based scaffolds, the effects of ethanol and ethylene oxide (EtO) sterilization on the cellular compatibility and the structural, chemical, and mechanical properties of uncrosslinked, UV crosslinked, or 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) crosslinked fibrin microthreads in neutral (EDCn) or acidic (EDCa) buffers are evaluated. EtO sterilization significantly reduces the tensile strength of uncrosslinked microthreads. Surface chemistry analyses show that EtO sterilization induces alkylation of EDCa microthreads leading to a significant reduction in myoblast attachment. The material properties of EDCn microthreads do not appear to be affected by the sterilization method. These results significantly enhance the understanding of how sterilization or crosslinking techniques affect the material properties of protein scaffolds. PMID:26847494

  7. Treatment of Tendon Injuries of the Lower Limb with Growth Factors Associated with Autologous Fibrin Scaffold or Collagenous Scaffold.

    PubMed

    Giannotti, Stefano; Dell'Osso, Giacomo; Bottai, Vanna; Ghilardi, Marco; Bugelli, Giulia; Lazzerini, Ilaria; Guido, Giulio

    2015-05-01

    Tendon injuries are an increasing problem in orthopedics as we are faced with a growing demand in sports and recreation and an aging population. Tendons have poor spontaneous regenerative capacity, and often, complete recovery after injury is not achieved. Once injured, tendons do not completely re-acquire the biological and biomechanical properties of normal tendons due to the formation of adhesions and scarring, and often these abnormalities in the arrangement and structure are risk factors for re-injury. These problems associated with the healing of tendon injuries are a challenge for clinicians and surgeons. This study examined 9 cases of subcutaneous injuries including quadriceps tendon (2 cases), patellar tendon (1 case), and Achilles tendon (6 cases), incomplete and complete, treated consecutively. The surgical technique has provided, as appropriate, the termino-terminal tenorraphy, techniques of plastics of rotation flap, reinsertion with suture anchors, and in one case tendon augmentation with cadaver tissue. In cases where we needed mechanical support to the suture, we used preloaded growth factors on porcine collagen scaffold; in cases where we needed only one biological support, we used fibrin scaffold. PMID:26055027

  8. Use of fibrin glue in preventing pseudorecurrence after laparoscopic total extraperitoneal repair of large indirect inguinal hernia

    PubMed Central

    Sürgit, Önder; Çavuşoğlu, Nadir Turgut; Ünal, Yılmaz; Koşar, Pınar Nergis; İçen, Duygu

    2016-01-01

    Purpose Seroma is among the most common complications of laparoscopic total extraperitoneal (TEP) for especially large indirect inguinal hernia, and may be regarded as a recurrence by some patients. A potential area localized behind the mesh and extending from the inguinal cord into the scrotum may be one of the major etiological factors of this complication. Our aim is to describe a novel technique in preventing pseudorecurrence by using fibrin sealant to close that potential dead space. Methods Forty male patients who underwent laparoscopic TEP for indirect inguinal hernia with at least 100-mL volume were included in this prospective clinical study. While fibrin sealant was used to close the potential dead space in the study group, nothing was used in the control group. The volume of postoperative fluid collection on ultrasound was compared between the groups. Results Patient characteristics and the volumes of hernia sac were similar between the 2 groups. The mean volume of postoperative fluid collection was found as 120.2 mL in the control group and 53.7 mL in the study group, indicating a statistical significance (P < 0.001). Conclusion Minimizing the potential dead space with a fibrin sealant can reduce the amount of postoperative fluid collection, namely the incidence of pseudorecurrence.

  9. Use of fibrin glue in preventing pseudorecurrence after laparoscopic total extraperitoneal repair of large indirect inguinal hernia

    PubMed Central

    Sürgit, Önder; Çavuşoğlu, Nadir Turgut; Ünal, Yılmaz; Koşar, Pınar Nergis; İçen, Duygu

    2016-01-01

    Purpose Seroma is among the most common complications of laparoscopic total extraperitoneal (TEP) for especially large indirect inguinal hernia, and may be regarded as a recurrence by some patients. A potential area localized behind the mesh and extending from the inguinal cord into the scrotum may be one of the major etiological factors of this complication. Our aim is to describe a novel technique in preventing pseudorecurrence by using fibrin sealant to close that potential dead space. Methods Forty male patients who underwent laparoscopic TEP for indirect inguinal hernia with at least 100-mL volume were included in this prospective clinical study. While fibrin sealant was used to close the potential dead space in the study group, nothing was used in the control group. The volume of postoperative fluid collection on ultrasound was compared between the groups. Results Patient characteristics and the volumes of hernia sac were similar between the 2 groups. The mean volume of postoperative fluid collection was found as 120.2 mL in the control group and 53.7 mL in the study group, indicating a statistical significance (P < 0.001). Conclusion Minimizing the potential dead space with a fibrin sealant can reduce the amount of postoperative fluid collection, namely the incidence of pseudorecurrence. PMID:27617253

  10. Morphogen and proinflammatory cytokine release kinetics from PRGF-Endoret fibrin scaffolds: evaluation of the effect of leukocyte inclusion.

    PubMed

    Anitua, E; Zalduendo, M M; Prado, R; Alkhraisat, M H; Orive, G

    2015-03-01

    The potential influence of leukocyte incorporation in the kinetic release of growth factors from platelet-rich plasma (PRP) may explain the conflicting efficiency of leukocyte platelet-rich plasma (L-PRP) scaffolds in tissue regeneration. To assess this hypothesis, leukocyte-free (PRGF-Endoret) and L-PRP fibrin scaffolds were prepared, and both morphogen and proinflammatory cytokine release kinetics were analyzed. Clots were incubated with culture medium to monitor protein release over 8 days. Furthermore, the different fibrin scaffolds were morphologically characterized. Results show that leukocyte-free fibrin matrices were homogenous while leukocyte-containing ones were heterogeneous, loose and cellular. Leukocyte incorporation produced a significant increase in the contents of proinflammatory cytokines interleukin (IL)-1β and IL-16 but not in the platelet-derived growth factors release (<1.5-fold). Surprisingly, the availability of vascular endothelial growth factor suffered an important decrease after 3 days of incubation in the case of L-PRP matrices. While the release of proinflammatory cytokines was almost absent or very low from PRGF-Endoret, the inclusion of leukocytes induced a major increase in these cytokines, which was characterized by the presence of a latent period. The PRGF-Endoret matrices were stable during the 8 days of incubation. The inclusion of leukocytes alters the growth factors release profile and also increased the dose of proinflammatory cytokines.

  11. Treatment of non-healing sternum wound after open-heart surgery with allogenic platelet-rich plasma and fibrin glue-preliminary outcomes

    PubMed Central

    Tashnizi, Mohammad Abbasi; Alamdari, Daryoush Hamidi; Khayami, Mohammad Esmail; Rahimi, Hamid Reza; Moeinipour, Aliasghar; Amouzeshi, Ahmad; Seifalian, Alexander M.

    2013-01-01

    Introduction: Non-healing wound in the sternal region after coronary arteries bypass graft surgery is a serious complication. For healing a chronic wound, several novel approaches have been proposed recently such as using bone marrow stem cells, platelets and fibrin glue (PFG); but a non-invasive method is highly desirable in the first approach for treatment. The current study was undertaken to evaluate the effect of the combination of PFG in one treatment. Materials and Methods: We report on the treatment of six patients with life-threatening chronic sternum wounds, which caused septicemia with multi-drug resistant pathogens. The ulcers were extensively debrided initially and were measured and photographed at weekly intervals. The combination of PFG was applied topically on the wound after every 2 days. Results: The wounds were completely closed in five patients and significantly reduced in size in one. There was no evidence of local or systemic complications and any abnormal tissue formation, keloid or hypertrophic scarring. Conclusions: Our study suggests, in the first approach, PFG can be used safely in order to heal a non healing sternum wound following coronary artery bypass surgery. PMID:24459346

  12. Differentiation within autologous fibrin scaffolds of porcine dermal cells with the mesenchymal stem cell phenotype.

    PubMed

    de la Puente, Pilar; Ludeña, Dolores; López, Marta; Ramos, Jennifer; Iglesias, Javier

    2013-02-01

    Porcine mesenchymal stem cells (pMSCs) are an attractive source of cells for tissue engineering because their properties are similar to those of human stem cells. pMSCs can be found in different tissues but their dermal origin has not been studied in depth. Additionally, MSCs differentiation in monolayer cultures requires subcultured cells, and these cells are at risk of dedifferentiation when implanting them into living tissue. Following this, we attempted to characterize the MSCs phenotype of porcine dermal cells and to evaluate their cellular proliferation and differentiation in autologous fibrin scaffolds (AFSs). Dermal biopsies and blood samples were obtained from 12 pigs. Dermal cells were characterized by flow cytometry. Frozen autologous plasma was used to prepare AFSs. pMSC differentiation was studied in standard structures (monolayers and pellets) and in AFSs. The pMSCs expressed the CD90 and CD29 markers of the mesenchymal lineage. AFSs afforded adipogenic, osteogenic and chondrogenic differentiation. The porcine dermis can be proposed to be a good source of MSCs with adequate proliferative capacity and a suitable expression of markers. The pMSCs also showed optimal proliferation and differentiation in AFSs, such that these might serve as a promising autologous and implantable material for use in tissue engineering.

  13. Synthetic vs natural scaffolds for human limbal stem cells

    PubMed Central

    Tominac Trcin, Mirna; Dekaris, Iva; Mijović, Budimir; Bujić, Marina; Zdraveva, Emilija; Dolenec, Tamara; Pauk-Gulić, Maja; Primorac, Dragan; Crnjac, Josip; Špoljarić, Branimira; Mršić, Gordan; Kuna, Krunoslav; Špoljarić, Daniel; Popović, Maja

    2015-01-01

    Aim To investigate the impact of synthetic electrospun polyurethane (PU) and polycaprolactone (PCL) nanoscaffolds, before and after hydrolytic surface modification, on viability and differentiation of cultured human eye epithelial cells, in comparison with natural scaffolds: fibrin and human amniotic membrane. Methods Human placenta was taken at elective cesarean delivery. Fibrin scaffolds were prepared from commercial fibrin glue kits. Nanoscaffolds were fabricated by electrospinning. Limbal cells were isolated from surpluses of human cadaveric cornea and seeded on feeder 3T3 cells. The scaffolds used for viability testing and immunofluorescence analysis were amniotic membrane, fibrin, PU, and PCL nanoscaffolds, with or without prior NaOH treatment. Results Scanning electron microscope photographs of all tested scaffolds showed good colony spreading of seeded limbal cells. There was a significant difference in viability performance between cells with highest viability cultured on tissue culture plastic and cells cultured on all other scaffolds. On the other hand, electrospun PU, PCL, and electrospun PCL treated with NaOH had more than 80% of limbal cells positive for stem cell marker p63 compared to only 27%of p63 positive cells on fibrin. Conclusion Natural scaffolds, fibrin and amniotic membrane, showed better cell viability than electrospun scaffolds. On the contrary, high percentages of p63 positive cells obtained on these scaffolds still makes them good candidates for efficient delivery systems for therapeutic purposes. PMID:26088849

  14. Platelet-rich plasma and fibrin glue-coated bioactive ceramics enhance growth and differentiation of goat bone marrow-derived stem cells.

    PubMed

    Nair, Manitha B; Varma, H K; John, Annie

    2009-07-01

    New biotechnologies such as tissue engineering require functionally active cells within supportive matrices where the physical and chemical stimulus provided by the matrix is indispensable to determine the cellular behavior. This study has investigated the influence of platelet-rich plasma (PRP) and fibrin glue (FG) on the functional activity of goat bone marrow-derived mesenchymal stem cells (gBMSCs) that differentiated into the osteogenic lineage. To achieve this goal, PRP and FG were separately coated on bioactive ceramics like hydroxyapatite (HA) and silica-coated HA (HASi), on which gBMSCs were seeded and induced to differentiate into the osteogenic lineage for 28 days. The cells were then analyzed for viability (lactate dehydrogenase assay: acridine orange and ethidium bromide staining), morphology (scanning electron microscopy), proliferation (picogreen assay), cell cycle assay (propidium iodide staining), and differentiation (alkaline phosphatase [ALP] activity and real-time PCR analysis of ALP, osteocalcin, and osteopontin gene). It has been observed that PRP and FG have appreciably favored the viability, spreading, and proliferation of osteogenic-induced gBMSCs. The osteopontin and osteocalcin expression was significantly enhanced on PRP- and FG-coated HA and HASi, but PRP had effect on neither ALP expression nor ALP activity. The results of this study have depicted that FG-coated ceramics were better than PRP-coated and bare matrices. Among all, the excellent performance was shown by FG coated HASi, which may be attributed to the communal action of the stimulus emanated by Si in HASi and the temporary extracellular matrix provided by FG over HASi. Thus, we can conclude that PRP or FG in combination with bioactive ceramics could possibly enhance the functional activity of cells to a greater extent, promoting the hybrid composite as a promising candidate for bone tissue engineering applications.

  15. Fibrin Scaffold as a Carrier for Mesenchymal Stem Cells and Growth Factors in Shoulder Rotator Cuff Repair.

    PubMed

    Voss, Andreas; McCarthy, Mary Beth; Allen, Donald; Cote, Mark P; Beitzel, Knut; Imhoff, Andreas B; Mazzocca, Augustus D

    2016-06-01

    With an increase in the aging population, rotator cuff tears are becoming more common. High failure rates with shoulder rotator cuff repair surgery have been persistent, prompting the introduction of biologic methods to promote healing. The aim of the present technique is to deliver stem cells and growth factors to the footprint of the repair site. A platelet-rich plasma (PRP) fibrin clot is used as a scaffold for the delivery of stem cells, by using PRP, to provide a source of growth factors, and platelet-poor plasma (PPP) as a source for fibrinogen for the matrix for the scaffold. In the second step, bone marrow is harvested from the proximal humerus, concentrated, and combined with the PRP and PPP. Using a customized device, we then activate the clotting process and transfer the scaffold containing the stem cells using a suture anchor onto the shoulder rotator cuff footprint. In an effort to promote healing, this technique reimplants autologous stem cells and growth factors into the operative site. This technique may serve as an alternative for typically used scaffolds such as collagen matrices or decellularized human dermis patches. PMID:27656360

  16. Simultaneous implant placement and bone regeneration around dental implants using tissue-engineered bone with fibrin glue, mesenchymal stem cells and platelet-rich plasma.

    PubMed

    Ito, Kenji; Yamada, Yoichi; Naiki, Takahito; Ueda, Minoru

    2006-10-01

    This study was undertaken to evaluate the use of tissue-engineered bone as grafting material for alveolar augmentation with simultaneous implant placement. Twelve adult hybrid dogs were used in this study. One month after the extraction of teeth in the mandible region, bone defects on both sides of the mandible were induced using a trephine bar with a diameter of 10 mm. Dog mesenchymal stem cells (dMSCs) were obtained via iliac bone biopsy and cultured for 4 weeks before implantation. After installing the dental implants, the defects were simultaneously implanted with the following graft materials: (i) fibrin, (ii) dMSCs and fibrin (dMSCs/fibrin), (iii) dMSCs, platelet-rich plasma (PRP) and fibrin (dMSCs/PRP/fibrin) and (iv) control (defect only). The implants were assessed by histological and histomorphometric analysis, 2, 4 and 8 weeks after implantation. The implants exhibited varying degrees of bone-implant contact (BIC). The BIC was 17%, 19% and 29% (control), 20%, 22% and 25% (fibrin), 22%, 32% and 42% (dMSCs/fibrin) and 25%, 49% and 53% (dMSCs/PRP/fibrin) after 2, 4 and 8 weeks, respectively. This study suggests that tissue-engineered bone may be of sufficient quality for predictable enhancement of bone regeneration around dental implants when used simultaneous by with implant placement.

  17. Enhanced Osteogenic and Vasculogenic Differentiation Potential of Human Adipose Stem Cells on Biphasic Calcium Phosphate Scaffolds in Fibrin Gels.

    PubMed

    van Esterik, Fransisca A S; Zandieh-Doulabi, Behrouz; Kleverlaan, Cornelis J; Klein-Nulend, Jenneke

    2016-01-01

    For bone tissue engineering synthetic biphasic calcium phosphate (BCP) with a hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) ratio of 60/40 (BCP60/40) is successfully clinically applied, but the high percentage of HA may hamper efficient scaffold remodelling. Whether BCP with a lower HA/β-TCP ratio (BCP20/80) is more desirable is still unclear. Vascular development is needed before osteogenesis can occur. We aimed to test the osteogenic and/or vasculogenic differentiation potential as well as degradation of composites consisting of human adipose stem cells (ASCs) seeded on BCP60/40 or BCP20/80 incorporated in fibrin gels that trigger neovascularization for bone regeneration. ASC attachment to BCP60/40 and BCP20/80 within 30 min was similar (>93%). After 11 days of culture BCP20/80-based composites showed increased alkaline phosphatase activity and DMP1 gene expression, but not RUNX2 and osteonectin expression, compared to BCP60/40-based composites. BCP20/80-based composites also showed enhanced expression of the vasculogenic markers CD31 and VEGF189, but not VEGF165 and endothelin-1. Collagen-1 and collagen-3 expression was similar in both composites. Fibrin degradation was increased in BCP20/80-based composites at day 7. In conclusion, BCP20/80-based composites showed enhanced osteogenic and vasculogenic differentiation potential compared to BCP60/40-based composites in vitro, suggesting that BCP20/80-based composites might be more promising for in vivo bone augmentation than BCP60/40-based composites. PMID:27547223

  18. Enhanced Osteogenic and Vasculogenic Differentiation Potential of Human Adipose Stem Cells on Biphasic Calcium Phosphate Scaffolds in Fibrin Gels

    PubMed Central

    2016-01-01

    For bone tissue engineering synthetic biphasic calcium phosphate (BCP) with a hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) ratio of 60/40 (BCP60/40) is successfully clinically applied, but the high percentage of HA may hamper efficient scaffold remodelling. Whether BCP with a lower HA/β-TCP ratio (BCP20/80) is more desirable is still unclear. Vascular development is needed before osteogenesis can occur. We aimed to test the osteogenic and/or vasculogenic differentiation potential as well as degradation of composites consisting of human adipose stem cells (ASCs) seeded on BCP60/40 or BCP20/80 incorporated in fibrin gels that trigger neovascularization for bone regeneration. ASC attachment to BCP60/40 and BCP20/80 within 30 min was similar (>93%). After 11 days of culture BCP20/80-based composites showed increased alkaline phosphatase activity and DMP1 gene expression, but not RUNX2 and osteonectin expression, compared to BCP60/40-based composites. BCP20/80-based composites also showed enhanced expression of the vasculogenic markers CD31 and VEGF189, but not VEGF165 and endothelin-1. Collagen-1 and collagen-3 expression was similar in both composites. Fibrin degradation was increased in BCP20/80-based composites at day 7. In conclusion, BCP20/80-based composites showed enhanced osteogenic and vasculogenic differentiation potential compared to BCP60/40-based composites in vitro, suggesting that BCP20/80-based composites might be more promising for in vivo bone augmentation than BCP60/40-based composites. PMID:27547223

  19. Mesenchymal stromal cells integrate and form longitudinally-aligned layers when delivered to injured spinal cord via a novel fibrin scaffold

    PubMed Central

    Hyatt, Alex J.T.; Wang, Difei; van Oterendorp, Christian; Fawcett, James W.; Martin, Keith R.

    2014-01-01

    Mesenchymal stromal cells (MSCs) have been shown to promote healing and regeneration in a number of CNS injury models and therefore there is much interest in the clinical use of these cells. For spinal cord injuries, a standard delivery method for MSCs is intraspinal injection, but this can result in additional injury and provides little control over how the cells integrate into the tissue. The present study examines the use of a novel fibrin scaffold as a new method of delivering MSCs to injured spinal cord. Use of the fibrin scaffold resulted in the formation of longitudinally-aligned layers of MSCs growing over the spinal cord lesion site. Host neurites were able to migrate into this MSC architecture and grow longitudinally. The length of the MSC bridge corresponded to the length of the fibrin scaffold. MSCs that were delivered via intraspinal injection were mainly oriented perpendicular to the plane of the spinal cord and remained largely restricted to the lesion site. Host neurites within the injected MSC graft were also oriented perpendicular to the plane of the spinal cord. PMID:24680849

  20. Mesenchymal stromal cells integrate and form longitudinally-aligned layers when delivered to injured spinal cord via a novel fibrin scaffold.

    PubMed

    Hyatt, Alex J T; Wang, Difei; van Oterendorp, Christian; Fawcett, James W; Martin, Keith R

    2014-05-21

    Mesenchymal stromal cells (MSCs) have been shown to promote healing and regeneration in a number of CNS injury models and therefore there is much interest in the clinical use of these cells. For spinal cord injuries, a standard delivery method for MSCs is intraspinal injection, but this can result in additional injury and provides little control over how the cells integrate into the tissue. The present study examines the use of a novel fibrin scaffold as a new method of delivering MSCs to injured spinal cord. Use of the fibrin scaffold resulted in the formation of longitudinally-aligned layers of MSCs growing over the spinal cord lesion site. Host neurites were able to migrate into this MSC architecture and grow longitudinally. The length of the MSC bridge corresponded to the length of the fibrin scaffold. MSCs that were delivered via intraspinal injection were mainly oriented perpendicular to the plane of the spinal cord and remained largely restricted to the lesion site. Host neurites within the injected MSC graft were also oriented perpendicular to the plane of the spinal cord.

  1. Fibrinogen and fibrin based micro and nano scaffolds incorporated with drugs, proteins, cells and genes for therapeutic biomedical applications

    PubMed Central

    Rajangam, Thanavel; An, Seong Soo A

    2013-01-01

    Over the past two decades, many types of natural and synthetic polymer-based micro- and nanocarriers, with exciting properties and applications, have been developed for application in various types of tissue regeneration, including bone, cartilage, nerve, blood vessels, and skin. The development of suitable polymers scaffold designs to aid the repair of specific cell types have created diverse and important potentials in tissue restoration. Fibrinogen (Fbg)- and fibrin (Fbn)-based micro- and nanostructures can provide suitable natural matrix environments. Since these primary materials are abundantly available in blood as the main coagulation proteins, they can easily interact with damaged tissues and cells through native biochemical interactions. Fbg- and Fbn-based micro and nanostructures can also be consecutively furnished/or encapsulated and specifically delivered, with multiple growth factors, proteins, and stem cells, in structures designed to aid in specific phases of the tissue regeneration process. The present review has been carried out to demonstrate the progress made with micro and nanoscaffold applications and features a number of applications of Fbg- and Fbn-based carriers in the field of biomaterials, including the delivery of drugs, active biomolecules, cells, and genes, that have been effectively used in tissue engineering and regenerative medicine. PMID:24106425

  2. Glorious Glue

    ERIC Educational Resources Information Center

    Guhin, Paula

    2010-01-01

    There's something irresistible about squeezing out lines and shapes with a bottle of glue. It's fun, yes. But, even better: it's tactile. The glue dries slightly raised on the surface, lending itself to several exciting treatments. In this article, the author describes some activities that confirm how a simple art material like glue can be…

  3. Fibrin glue and stents in the treatment of gastrojejunal leaks after laparoscopic gastric bypass: a case series and review of the literature.

    PubMed

    Victorzon, Mikael; Victorzon, Sarita; Peromaa-Haavisto, Pipsa

    2013-10-01

    Laparoscopic Roux-en-Y gastric bypass (LRYGB) is the most commonly performed bariatric/metabolic operation in Europe. Different treatment options for the management of gastrojejunal (GJ) leaks following LRYGB have been published. We looked at our own experience with GJ leaks after 645 consecutive LRYGB operations and reviewed the literature with focus on the use of fibrin sealant and self-expandable metal stents as treatment options. Patient data were prospectively collected in the hospital's database for bariatric patients. All patients with confirmed GJ leaks were reviewed. Patients with GJ leaks were actively treated by a combination of laparoscopic drainage and endoscopic fibrin sealant injections and/or stenting. Six patients (0.93%) have been treated for GJ leaks. All leaks were successfully treated and there was no leak-related mortality. The mean (SD) time for closure of the leaks and length of hospital stay was 19.5 days (6.2) and 23.2 days (3.7). The literature concerning endoscopic treatment options in case of GJ leaks following LRYGB operations is scarce and inconclusive. Immediate and active treatment with a combination of operative and endoscopic treatment options, rather than choosing only one treatment over another, may enhance the recovery process.

  4. Delivery of PDGF-B and BMP-7 by mesoporous bioglass/silk fibrin scaffolds for the repair of osteoporotic defects.

    PubMed

    Zhang, Yufeng; Cheng, Ning; Miron, Richard; Shi, Bin; Cheng, Xiangrong

    2012-10-01

    Osteoporosis is a chronic disease affecting millions of people worldwide caused by an imbalance between bone-forming osteoblasts and bone-resorbing osteoclasts. Despite recent developments in pharmacological agents to prevent osteoporotic-related fractures, much less attention has been placed on the repair of bone defects following fracture. Critical to this process is the recruitment of mesenchymal stem cells (MSCs) to defect sites by growth factors. One method which has been effective for the sustained release of growth factors is that of gene therapy. The aim of the present study was to investigate newly developed mesoporous bioglass/silk fibrin scaffolds containing adPDGF-b and adBMP-7 into osteoporotic critical-sized femur defects in ovariectomised rats following treatment periods of 2 and 4 weeks. In vivo osteogenetic efficiency evaluated by μ-CT analysis, hematoxylin and eosin staining, and immunohistochemical (type I collagen, osteopontin and BSP) revealed significantly new bone formation in defects containing adenovirus for both PDGF-b and BMP-7 when compared to scaffolds alone and scaffolds containing BMP-7. TRAP-positive staining also demonstrated the ability for these scaffolds to be degraded over time and initiate bone turnover/remodeling. Although the use of gene therapy for clinical applications is still in its infancy, results from the present study demonstrate their potent ability to recruit mesenchymal progenitor cells through sustained release of PDGF-b and BMP-7 which may be beneficial for patients suffering from osteoporotic-related fractures.

  5. Survival, Differentiation, and Migration of High-Purity Mouse Embryonic Stem Cell-derived Progenitor Motor Neurons in Fibrin Scaffolds after Sub-Acute Spinal Cord Injury.

    PubMed

    McCreedy, D A; Wilems, T S; Xu, H; Butts, J C; Brown, C R; Smith, A W; Sakiyama-Elbert, S E

    2014-11-01

    Embryonic stem (ES) cells can be differentiated into many neural cell types that hold great potential as cell replacement therapies following spinal cord injury (SCI). Coupling stem cell transplantation with biomaterial scaffolds can produce a unified combination therapy with several potential advantages including enhanced cell survival, greater transplant retention, reduced scarring, and improved integration at the transplant/host interface. Undesired cell types, however, are commonly present in ES-cell derived cultures due to the limited efficiency of most ES cell induction protocols. Heterogeneous cell populations can confound the interaction between the biomaterial and specific neural populations leading to undesired outcomes. In particular, biomaterials scaffolds may enhance tumor formation by promoting survival and proliferation of undifferentiated ES cells that can persist after induction. Methods for purification of specific ES cell-derived neural populations are necessary to recognize the full potential of combination therapies involving biomaterials and ES cell-derived neural populations. We previously developed a method for enriching ES cell-derived progenitor motor neurons (pMNs) induced from mouse ES cells via antibiotic selection and showed that the enriched cell populations are depleted of pluripotent stem cells. In this study, we demonstrate the survival and differentiation of enriched pMNs within three dimensional (3D) fibrin scaffolds in vitro and when transplanted into a sub-acute dorsal hemisection model of SCI into neurons, oligodendrocytes and astrocytes. PMID:25346848

  6. Leukocyte inclusion within a platelet rich plasma-derived fibrin scaffold stimulates a more pro-inflammatory environment and alters fibrin properties.

    PubMed

    Anitua, Eduardo; Zalduendo, Mar; Troya, María; Padilla, Sabino; Orive, Gorka

    2015-01-01

    One of the main differences among platelet-rich plasma (PRP) products is the inclusion of leukocytes that may affect the biological efficacy of these autologous preparations. The purpose of this study was to evaluate whether the addition of leukocytes modified the morphological, biomechanical and biological properties of PRP under normal and inflammatory conditions. The release of pro-inflammatory cytokines from plasma rich in growth factors (PRGF) and leukocyte-platelet rich plasma (L-PRP) scaffolds was determined by enzyme-linked immunosorbent assay (ELISA) and was significantly increased under an inflammatory condition when leukocytes were included in the PRP. Fibroblasts and osteoblasts treated with L-PRP, under an inflammatory situation, underwent a greater activation of NFĸB pathway, proliferated significantly less and secreted a higher concentration of pro-inflammatory cytokines. These cellular events were assessed through Western blot and fluorimetric and ELISA methods, respectively. Therefore, the inclusion of leukocytes induced significantly higher pro-inflammatory conditions.

  7. Leukocyte Inclusion within a Platelet Rich Plasma-Derived Fibrin Scaffold Stimulates a More Pro-Inflammatory Environment and Alters Fibrin Properties

    PubMed Central

    Anitua, Eduardo; Zalduendo, Mar; Troya, María; Padilla, Sabino; Orive, Gorka

    2015-01-01

    One of the main differences among platelet-rich plasma (PRP) products is the inclusion of leukocytes that may affect the biological efficacy of these autologous preparations. The purpose of this study was to evaluate whether the addition of leukocytes modified the morphological, biomechanical and biological properties of PRP under normal and inflammatory conditions. The release of pro-inflammatory cytokines from plasma rich in growth factors (PRGF) and leukocyte-platelet rich plasma (L-PRP) scaffolds was determined by enzyme-linked immunosorbent assay (ELISA) and was significantly increased under an inflammatory condition when leukocytes were included in the PRP. Fibroblasts and osteoblasts treated with L-PRP, under an inflammatory situation, underwent a greater activation of NFĸB pathway, proliferated significantly less and secreted a higher concentration of pro-inflammatory cytokines. These cellular events were assessed through Western blot and fluorimetric and ELISA methods, respectively. Therefore, the inclusion of leukocytes induced significantly higher pro-inflammatory conditions. PMID:25823008

  8. Polylactic-co-glycolic acid mesh coated with fibrin or collagen and biological adhesive substance as a prefabricated, degradable, biocompatible, and functional scaffold for regeneration of the urinary bladder wall.

    PubMed

    Salem, Salah Abood; Hwei, Ng Min; Bin Saim, Aminuddin; Ho, Christopher C K; Sagap, Ismail; Singh, Rajesh; Yusof, Mohd Reusmaazran; Md Zainuddin, Zulkifili; Idrus, Ruszymah Bt Hj

    2013-08-01

    The chief obstacle for reconstructing the bladder is the absence of a biomaterial, either permanent or biodegradable, that will function as a suitable scaffold for the natural process of regeneration. In this study, polylactic-co-glycolic acid (PLGA) plus collagen or fibrin was evaluated for its suitability as a scaffold for urinary bladder construct. Human adipose-derived stem cells (HADSCs) were cultured, followed by incubation in smooth muscle cells differentiation media. Differentiated HADSCs were then seeded onto PLGA mesh supported with collagen or fibrin. Evaluation of cell-seeded PLGA composite immersed in culture medium was performed under a light and scanning microscope. To determine if the composite is compatible with the urodynamic properties of urinary bladder, porosity and leaking test was performed. The PLGA samples were subjected to tensile testing was pulled until PLGA fibers break. The results showed that the PLGA composite is biocompatible to differentiated HADSCs. PLGA-collagen mesh appeared to be optimal as a cell carrier while the three-layered PLGA-fibrin composite is better in relation to its leaking/ porosity property. A biomechanical test was also performed for three-layered PLGA with biological adhesive and three-layered PLGA alone. The tensile stress at failure was 30.82 ± 3.80 (MPa) and 34.36 ± 2.57 (MPa), respectively. Maximum tensile strain at failure was 19.42 ± 2.24 (mm) and 23.06 ± 2.47 (mm), respectively. Young's modulus was 0.035 ± 0.0083 and 0.043 ± 0.012, respectively. The maximum load at break was 58.55 ± 7.90 (N) and 65.29 ± 4.89 (N), respectively. In conclusion, PLGA-Fibrin fulfils the criteria as a scaffold for urinary bladder reconstruction.

  9. The potential of 3-dimensional construct engineered from poly(lactic-co-glycolic acid)/fibrin hybrid scaffold seeded with bone marrow mesenchymal stem cells for in vitro cartilage tissue engineering.

    PubMed

    Abdul Rahman, Rozlin; Mohamad Sukri, Norhamiza; Md Nazir, Noorhidayah; Ahmad Radzi, Muhammad Aa'zamuddin; Zulkifly, Ahmad Hafiz; Che Ahmad, Aminudin; Hashi, Abdurezak Abdulahi; Abdul Rahman, Suzanah; Sha'ban, Munirah

    2015-08-01

    Articular cartilage is well known for its simple uniqueness of avascular and aneural structure that has limited capacity to heal itself when injured. The use of three dimensional construct in tissue engineering holds great potential in regenerating cartilage defects. This study evaluated the in vitro cartilaginous tissue formation using rabbit's bone marrow mesenchymal stem cells (BMSCs)-seeded onto poly(lactic-co-glycolic acid) PLGA/fibrin and PLGA scaffolds. The in vitro cartilaginous engineered constructs were evaluated by gross inspection, histology, cell proliferation, gene expression and sulphated glycosaminoglycan (sGAG) production at week 1, 2 and 3. After 3 weeks of culture, the PLGA/fibrin construct demonstrated gross features similar to the native tissue with smooth, firm and glistening appearance, superior histoarchitectural and better cartilaginous extracellular matrix compound in concert with the positive glycosaminoglycan accumulation on Alcian blue. Significantly higher cell proliferation in PLGA/fibrin construct was noted at day-7, day-14 and day-21 (p<0.05 respectively). Both constructs expressed the accumulation of collagen type II, collagen type IX, aggrecan and sox9, showed down-regulation of collagen type I as well as produced relative sGAG content with PLGA/fibrin construct exhibited better gene expression in all profiles and showed significantly higher relative sGAG content at each time point (p<0.05). This study suggested that with optimum in vitro manipulation, PLGA/fibrin when seeded with pluripotent non-committed BMSCs has the capability to differentiate into chondrogenic lineage and may serve as a prospective construct to be developed as functional tissue engineered cartilage.

  10. Fibrinogen-fibrin conversion and inhibition of fibrinolysis.

    PubMed

    Stemberger, A; Blümel, G

    1982-08-01

    The fibrin adhesion technique is the imitation of the last step of the coagulation system. Fibrinogen is converted by thrombin into fibrin and stabilized by factor XIII. Fibrin sticks to the tissue and the tissue is adapted by syneresis. Local application of aprotinin to the thrombin solution is necessary in order to inhibit premature lysis of the fibrin film. This technique is now used in some selected cases in man such as fixation of cartilage, tendon, sealing of colonic anastomoses and preclotting of vessel grafts. An excellent hemostyptic effect of the fibrin glue in combination with absorbable collagen tampons was found. This combination technique is now used to seal parenchymatous organs and to stop hemorrhage in patients with defective hemostasis particularly those undergoing open heart surgery.

  11. Fibrin-based 3D Matrices Induce Angiogenic Behavior of Adipose-derived Stem Cells

    PubMed Central

    Chung, Eunna; Rytlewski, Julie A; Merchant, Arjun G; Dhada, Kabir S; Lewis, Evan W; Suggs, Laura J.

    2015-01-01

    Engineered three-dimensional biomaterials are known to affect the regenerative capacity of stem cells. The extent to which these materials can modify cellular activities is still poorly understood, particularly for adipose-derived stem cells (ASCs). This study evaluates PEGylated fibrin (P-fibrin) gels as an ASC-carrying scaffold for encouraging local angiogenesis by comparing with two commonly used hydrogels (i.e. collagen and fibrin) in the tissue-engineering field. Human ASCs in P-fibrin were compared to cultures in collagen and fibrin under basic growth media without any additional soluble factors. ASCs proliferated similarly in all gel scaffolds but showed significantly elongated morphologies in the P-fibrin gels relative to other gels. P-fibrin elicited higher von Willebrand factor expression in ASCs than either collagen or fibrin while cells in collagen expressed more smooth muscle alpha actin than in other gels. VEGF was secreted more at 7 days in fibrin and P-fibrin than in collagen and several other angiogenic and immunomodulatory cytokines were similarly enhanced. Fibrin-based matrices appear to activate angiogenic signaling in ASCs while P-fibrin matrices are uniquely able to also drive a vessel-like ASC phenotype. Collectively, these results suggest that P-fibrin promotes the angiogenic potential of ASC-based therapeutic applications. PMID:25600400

  12. [Conservative anal fistula treatment with collagenic plug and human fibrin sealant. Preliminary results].

    PubMed

    Gubitosi, A; Moccia, G; Malinconico, F A; Docimo, G; Ruggiero, R; Iside, G; Avenia, N; Docimo, L; Foroni, F; Gilio, F; Sparavigna, L; Agresti, M

    2009-01-01

    The authors, on the basis of a long clinical experience with human fibrin glue in general surgery, compared two different extracellular matrix (collagen), Surgisis and TissueDura, with human fibrin glue, applied during the operation, and sometimes in postoperative, to obtain the healing of perianal fistulas. The collagenic extracellular matrix provides, according to the rationale suggested, an optimal three-dimensional structure for the fibroblastic implant and neoangiogenesis, hence for the fistula "fibrotizzation" and closure. The encouraging results for transphincteric fistulas and a simple and easy technique push to researchers on samples statistically significant. PMID:19272233

  13. Enhanced Neurite Growth from Mammalian Neurons in Three-Dimensional Salmon Fibrin Gels

    PubMed Central

    Ju, Yo-El; Janmey, Paul A.; McCormick, Margaret; Sawyer, Evelyn S.; Flanagan, Lisa A.

    2007-01-01

    Three-dimensional fibrin matrices have been used as cellular substrates in vitro and as bridging materials for central nervous system repair. Cells can be embedded within fibrin gels since the polymerization process is non-toxic, making fibrin an attractive scaffold for transplanted cells. Most studies have utilized fibrin prepared from human or bovine blood proteins. However, fish fibrin may be well suited for neuronal growth since fish undergo remarkable central nervous system regeneration and molecules implicated in this process are present in fibrin. We assessed the growth of mammalian central nervous system neurons in bovine, human, and salmon fibrin and found that salmon fibrin gels encouraged the greatest degree of neurite (dendrite and axon) growth and were the most resistant to degradation by cellular proteases. The neurite growth-promoting effect was not due to the thrombin used to polymerize the gels or to any copurifying plasminogen. Co-purified fibronectin partially accounted for the effect on neurites, and blockade of fibrinogen/fibrin-binding integrins markedly decreased neurite growth. Anion exchange chromatography revealed different elution profiles for salmon and mammalian fibrinogens. These data demonstrate that salmon fibrin encourages the growth of neurites from mammalian neurons and suggest that salmon fibrin may be a beneficial scaffold for neuronal regrowth after CNS injury. PMID:17258313

  14. Characterization of Chondrocyte Scaffold Carriers for Cell-based Gene Therapy in Articular Cartilage Repair

    PubMed Central

    Shui, Wei; Yin, Liangjun; Luo, Jeffrey; Li, Ruidong; Zhang, Wenwen; Zhang, Jiye; Huang, Wei; Hu, Ning; Liang, Xi; Deng, Zhong-Liang; Hu, Zhenming; Shi, Lewis; Luu, Hue H.; Haydon, Rex C.; He, Tong-Chuan; Ho, Sherwin

    2014-01-01

    Articular cartilage lesions in the knee are common injuries. Chondrocyte transplant represents a promising therapeutic modality for articular cartilage injuries. Here, we characterize the viability and transgene expression of articular chondrocytes cultured in 3-D scaffolds provided by four types of carriers. Articular chondrocytes are isolated from rabbit knees and cultured in four types of scaffolds: type I collagen sponge, fibrin glue, hyaluronan, and Open-cell PolyLactic Acid (OPLA). The cultured cells are transduced with adenovirus expressing green fluorescence protein (AdGFP) and luciferase (AdGL3-Luc). The viability and gene expression in the chondrocytes are determined with fluorescence microscopy and luciferase assay. Cartilage matrix production is assessed by Alcian blue staining. Rabbit articular chondrocytes are effectively infected by AdGFP and exhibited sustained GFP expression. All tested scaffolds support the survival and gene expression of the infected chondrocytes. However, the highest transgene expression is observed in the OPLA carrier. At four weeks, Alcian blue-positive matrix materials are readily detected in OPLA cultures. Thus, our results indicate that, while all tested carriers can support the survival of chondrocytes, OPLA supports the highest transgene expression and is the most conductive scaffold for matrix production, suggesting that OPLA may be a suitable scaffold for cell-based gene therapy of articular cartilage repairs. PMID:23629940

  15. TAPE: A Biodegradable Hemostatic Glue Inspired by a Ubiquitous Compound in Plants for Surgical Application.

    PubMed

    Kim, Keumyeon; Lee, Haeshin; Hong, Seonki

    2016-01-01

    This video describes the simplest protocol for preparing biodegradable surgical glue that has an effective hemostatic ability and greater water-resistant adhesion strength than commercial tissue adhesives. Medical adhesives have attracted great attention as potential alternative tools to sutures and staples due to their convenience in usage with minimal invasiveness. Although there are several protocols for developing tissue adhesives including those commercially available such as fibrin glues and cyanoacrylate-based materials, mostly they require a series of chemical syntheses of organic molecules, or complicated protein-purification methods, in the case of bio-driven materials (i.e., fibrin glue). Also, the development of surgical glues exhibiting high adhesive properties while maintaining biodegradability is still a challenge due to difficulties in achieving good performance in the wet environment of the body. We illustrate a new method to prepare a medical glue, known as TAPE, by the weight-based separation of a water-immiscible supramolecular aggregate formed after a physical mixing of a plant-derived, wet-resistant adhesive molecule, Tannic Acid (TA), and a well-known biopolymer, Poly(Ethylene) glycol (PEG). With our approach, TAPE shows high adhesion strength, which is 2.5-fold more than commercial fibrin glue in the presence of water. Furthermore, TAPE is biodegradable in physiological conditions and can be used as a potent hemostatic glue against tissue bleeding. We expect the widespread use of TAPE in a variety of medical settings and drug delivery applications, such as polymers for muco-adhesion, drug depots, and others. PMID:27341544

  16. Glue Guns: Aiming for Safety

    ERIC Educational Resources Information Center

    Roy, Ken

    2010-01-01

    While glue guns are very useful, there are safety issues. Regardless of the temperature setting, glue guns can burn skin. The teacher should demonstrate and supervise the use of glue guns and have a plan should a student get burned. There should be an initial first aid protocol in place, followed by a visit to the school nurse. An accident report…

  17. Structural basis for the nonlinear mechanics of fibrin networks under compression.

    PubMed

    Kim, Oleg V; Litvinov, Rustem I; Weisel, John W; Alber, Mark S

    2014-08-01

    Fibrin is a protein polymer that forms a 3D filamentous network, a major structural component of protective physiological blood clots as well as life threatening pathological thrombi. It plays an important role in wound healing, tissue regeneration and is widely employed in surgery as a sealant and in tissue engineering as a scaffold. The goal of this study was to establish correlations between structural changes and mechanical responses of fibrin networks exposed to compressive loads. Rheological measurements revealed nonlinear changes of fibrin network viscoelastic properties under dynamic compression, resulting in network softening followed by its dramatic hardening. Repeated compression/decompression enhanced fibrin clot stiffening. Combining fibrin network rheology with simultaneous confocal microscopy provided direct evidence of structural modulations underlying nonlinear viscoelasticity of compressed fibrin networks. Fibrin clot softening in response to compression strongly correlated with fiber buckling and bending, while hardening was associated with fibrin network densification. Our results suggest a complex interplay of entropic and enthalpic mechanisms accompanying structural changes and accounting for the nonlinear mechanical response in fibrin networks undergoing compressive deformations. These findings provide new insight into the fibrin clot structural mechanics and can be useful for designing fibrin-based biomaterials with modulated viscoelastic properties.

  18. Structural basis for the nonlinear mechanics of fibrin networks under compression.

    PubMed

    Kim, Oleg V; Litvinov, Rustem I; Weisel, John W; Alber, Mark S

    2014-08-01

    Fibrin is a protein polymer that forms a 3D filamentous network, a major structural component of protective physiological blood clots as well as life threatening pathological thrombi. It plays an important role in wound healing, tissue regeneration and is widely employed in surgery as a sealant and in tissue engineering as a scaffold. The goal of this study was to establish correlations between structural changes and mechanical responses of fibrin networks exposed to compressive loads. Rheological measurements revealed nonlinear changes of fibrin network viscoelastic properties under dynamic compression, resulting in network softening followed by its dramatic hardening. Repeated compression/decompression enhanced fibrin clot stiffening. Combining fibrin network rheology with simultaneous confocal microscopy provided direct evidence of structural modulations underlying nonlinear viscoelasticity of compressed fibrin networks. Fibrin clot softening in response to compression strongly correlated with fiber buckling and bending, while hardening was associated with fibrin network densification. Our results suggest a complex interplay of entropic and enthalpic mechanisms accompanying structural changes and accounting for the nonlinear mechanical response in fibrin networks undergoing compressive deformations. These findings provide new insight into the fibrin clot structural mechanics and can be useful for designing fibrin-based biomaterials with modulated viscoelastic properties. PMID:24840618

  19. Structural basis for the nonlinear mechanics of fibrin networks under compression

    PubMed Central

    Kim, Oleg V.; Litvinov, Rustem I.; Weisel, John W.; Alber, Mark S.

    2014-01-01

    Fibrin is a protein polymer that forms a 3D filamentous network, a major structural component of protective physiological blood clots as well as life threatening pathological thrombi. It plays an important role in wound healing, tissue regeneration and is widely employed in surgery as a sealant and in tissue engineering as a scaffold. The goal of this study was to establish correlations between structural changes and mechanical responses of fibrin networks exposed to compressive loads. Rheological measurements revealed nonlinear changes of fibrin network viscoelastic properties under dynamic compression, resulting in network softening followed by its dramatic hardening. Repeated compression/decompression enhanced fibrin clot stiffening. Combining fibrin network rheology with simultaneous confocal microscopy provided direct evidence of structural modulations underlying nonlinear viscoelasticity of compressed fibrin networks. Fibrin clot softening in response to compression strongly correlated with fiber buckling and bending, while hardening was associated with fibrin network densification. Our results suggest a complex interplay of entropic and enthalpic mechanisms accompanying structural changes and accounting for the nonlinear mechanical response in fibrin networks undergoing compressive deformations. These findings provide new insight into the fibrin clot structural mechanics and can be useful for designing fibrin-based biomaterials with modulated viscoelastic properties. PMID:24840618

  20. Autologous fibrin tissue adhesive for ossicular reconstruction in cats.

    PubMed

    Peters, B R; Strunk, C L; Fulmer, R P

    1992-11-01

    Autologous fibrin tissue adhesive is currently the most promising adhesive for otologic use with respect to strength and biocompatibility without the risk of transmissable disease that is of concern with the commercially prepared fibrin adhesive. We set out to evaluate the practicality of preparing autologous fibrin adhesive in cats and to see if the adhesive's duration and strength of bonding was sufficient to allow natural tissue union to occur with various grafting materials. Autologous fibrin adhesive was prepared preoperatively from ten cats using the ammonium sulfate precipitation technique. Twenty otologic procedures were performed in which the incus long process was resected and the defect bridged with one of four grafting materials: autograft ossicular bone, bone pate-fibrin glue, porous hydroxylapatite, and Plastipore-bone pate. All grafts were secured with the autologous adhesive. The cats were sacrificed at 6 and 12 weeks. We found the the autologous adhesive provided adequate duration and strength of support to enable a firm tissue union between all the grafting materials and the adjoining incus and stapes. PMID:1449181

  1. Characterisation of a novel light activated adhesive scaffold: Potential for device attachment.

    PubMed

    Ark, Morris; Boughton, Philip; Lauto, Antonio; Tran, Giang T; Chen, Yongjuan; Cosman, Peter H; Dunstan, Colin R

    2016-09-01

    .61±2.81kPa after 15min of light activation, this is comparable to the adhesion strength of fibrin glue on scaffolds. Cell attachment was seen to be similar to the controls, but cells appeared to have better cell survivability. In conclusion, the RBC-scaffolds show promise for use as a novel light activated attachment device with potential applications in attaching an anti-reflux valve in the lower oesophagus and also in wound healing applications for stomach ulcers. PMID:27281161

  2. Characterisation of a novel light activated adhesive scaffold: Potential for device attachment.

    PubMed

    Ark, Morris; Boughton, Philip; Lauto, Antonio; Tran, Giang T; Chen, Yongjuan; Cosman, Peter H; Dunstan, Colin R

    2016-09-01

    .61±2.81kPa after 15min of light activation, this is comparable to the adhesion strength of fibrin glue on scaffolds. Cell attachment was seen to be similar to the controls, but cells appeared to have better cell survivability. In conclusion, the RBC-scaffolds show promise for use as a novel light activated attachment device with potential applications in attaching an anti-reflux valve in the lower oesophagus and also in wound healing applications for stomach ulcers.

  3. [The initial trial of the clinical use of FK-1 glue in surgical interventions].

    PubMed

    Abzhueva, O V; Rusanov, V M; Zhidkov, I L

    2000-01-01

    The article presents results of a comparative clinical trial of the preparation "fibrinous glue" (FK-1) and "Beriplast" in operations on the lungs for hermetization of the wound and the lung as well as in reconstructive plastic gynecological operations. Intraoperative hermetization in operations on the lungs was obtained in 67% of the cases when using "FK-1" and in 64% with "Beriplast". In all the cases the lung was spread during 12 hours after operation. The visual intraoperative assessment of using "FK-1" and control laparoscopy on the 4th-5th days after operation showed its good effect in gynecological procedures. Clinical trials of the new domestic fibrinous glue "FK-1" in surgical and gynecological clinics confirmed its high medical effectiveness.

  4. Glue Sniffers with Special Needs.

    ERIC Educational Resources Information Center

    O'Connor, Denis

    1987-01-01

    Glue sniffing and solvent misuse have seriously affected children and teenagers throughout the United Kingdom. This article discusses glue sniffing in terms of prevalence, association with disability, physical and psychological effects, signs and symptoms, counseling for sniffers, and successful interventions including an approach using videotape…

  5. 21 CFR 178.3120 - Animal glue.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Animal glue. 178.3120 Section 178.3120 Food and... Animal glue. Animal glue may be safely used as a component of articles intended for use in producing... the provisions of this section. (a) Animal glue consists of the proteinaceous extractives...

  6. 21 CFR 178.3120 - Animal glue.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Animal glue. 178.3120 Section 178.3120 Food and... and Production Aids § 178.3120 Animal glue. Animal glue may be safely used as a component of articles..., transporting, or holding food, subject to the provisions of this section. (a) Animal glue consists of...

  7. 21 CFR 178.3120 - Animal glue.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Animal glue. 178.3120 Section 178.3120 Food and... and Production Aids § 178.3120 Animal glue. Animal glue may be safely used as a component of articles..., transporting, or holding food, subject to the provisions of this section. (a) Animal glue consists of...

  8. 21 CFR 178.3120 - Animal glue.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Animal glue. 178.3120 Section 178.3120 Food and... and Production Aids § 178.3120 Animal glue. Animal glue may be safely used as a component of articles..., transporting, or holding food, subject to the provisions of this section. (a) Animal glue consists of...

  9. 21 CFR 178.3120 - Animal glue.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Animal glue. 178.3120 Section 178.3120 Food and... and Production Aids § 178.3120 Animal glue. Animal glue may be safely used as a component of articles..., transporting, or holding food, subject to the provisions of this section. (a) Animal glue consists of...

  10. Aulogous fibrin sealant (Vivostat®) in the neurosurgical practice: Part II: Vertebro-spinal procedures

    PubMed Central

    Graziano, Francesca; Maugeri, Rosario; Basile, Luigi; Meccio, Favia; Iacopino, Domenico Gerardo

    2016-01-01

    Background: Epidural hematomas, cerebrospinal fluid fistula, and spinal infections are challenging postoperative complications following vertebro-spinal procedures. We report our preliminary results using autologous fibrin sealant as both fibrin glue and a hemostatic during these operations. Methods: Prospectively, between January 2013 and March 2015, 68 patients received an autologous fibrin sealant prepared with the Vivostat® system applied epidurally to provide hemostasis and to seal the dura. The surgical technique, time to bleeding control, and associated complications were recorded. Results: Spinal procedures were performed in 68 patients utilizing autologous fibrin glue/Vivostat® to provide rapid hemostasis and/or to seal the dura. Only 2 patients developed postoperative dural fistulas while none exhibited hemorrhages, allergic reactions, systemic complications, or infections. Conclusions: In this preliminary study, the application of autologous fibrin sealant with Vivostat® resulted in rapid hemostasis and/or acted as an effective dural sealant. Although this product appears to be safe and effective, further investigations are warranted. PMID:26904371

  11. Microstructural and Mechanical Differences Between Digested Collagen-Fibrin Co-Gels and Pure Collagen and Fibrin Gels

    PubMed Central

    Lai, Victor K.; Frey, Christina R.; Kerandi, Allan M.; Lake, Spencer P.; Tranquillo, Robert T.; Barocas, Victor H.

    2012-01-01

    Collagen and fibrin are important extra-cellular matrix (ECM) components in the body, providing structural integrity to various tissues. These biopolymers are also common scaffolds used in tissue engineering. This study investigated how co-gelation of collagen and fibrin affected the properties of each individual protein network. Collagen-fibrin co-gels were cast and subsequently digested using either plasmin or collagenase; the microstructure and mechanical behavior of the resulting networks were then compared with respective pure collagen or fibrin gels of the same protein concentration. The morphologies of the collagen networks were further analyzed via 3-D network reconstruction from confocal image z-stacks. Both collagen and fibrin exhibited a decrease in mean fiber diameter when formed in the co-gels compared to the pure gels; this microstructural change was accompanied by increased failure strain and decreased tangent modulus for both collagen and fibrin following selected digestion of the co-gels. In addition, analysis of the reconstructed collagen networks indicated presence of very long fibers and clustering of fibrils, resulting in very high connectivities for collagen networks formed in co-gels. PMID:22828381

  12. Transglutaminases: nature's biological glues.

    PubMed Central

    Griffin, Martin; Casadio, Rita; Bergamini, Carlo M

    2002-01-01

    Transglutaminases (Tgases) are a widely distributed group of enzymes that catalyse the post-translational modification of proteins by the formation of isopeptide bonds. This occurs either through protein cross-linking via epsilon-(gamma-glutamyl)lysine bonds or through incorporation of primary amines at selected peptide-bound glutamine residues. The cross-linked products, often of high molecular mass, are highly resistant to mechanical challenge and proteolytic degradation, and their accumulation is found in a number of tissues and processes where such properties are important, including skin, hair, blood clotting and wound healing. However, deregulation of enzyme activity generally associated with major disruptions in cellular homoeostatic mechanisms has resulted in these enzymes contributing to a number of human diseases, including chronic neurodegeneration, neoplastic diseases, autoimmune diseases, diseases involving progressive tissue fibrosis and diseases related to the epidermis of the skin. In the present review we detail the structural and regulatory features important in mammalian Tgases, with particular focus on the ubiquitous type 2 tissue enzyme. Physiological roles and substrates are discussed with a view to increasing and understanding the pathogenesis of the diseases associated with transglutaminases. Moreover the ability of these enzymes to modify proteins and act as biological glues has not gone unnoticed by the commercial sector. As a consequence, we have included some of the present and future biotechnological applications of this increasingly important group of enzymes. PMID:12366374

  13. Fibrin-based biomaterials: Modulation of macroscopic properties through rational design at the molecular level

    PubMed Central

    Brown, Ashley C.; Barker, Thomas H.

    2013-01-01

    Fibrinogen is one of the primary components of the coagulation cascade and rapidly forms an insoluble matrix following tissue injury. In addition to its important role in hemostasis, fibrin acts as a scaffold for tissue repair and provides important cues for directing cell phenotype following injury. Because of these properties and the ease of polymerization of the material, fibrin has been widely utilized as a biomaterial for over a century. Modifying the macroscopic properties of fibrin, such as elasticity and porosity, has been somewhat elusive until recently, yet with a molecular-level rational design approach can now be somewhat easily modified through alterations of molecular interactions key to the protein’s polymerization process. This review outlines the biochemistry of fibrin and discusses methods for modification of molecular interactions and their application to fibrin based biomaterials. PMID:24056097

  14. Nanocavities trapped along fibrin fibers allow the diffusion of thrombolytic drugs

    NASA Astrophysics Data System (ADS)

    De Spirito, Marco; Missori, Mauro; Maulucci, Giuseppe; Teixeira, Josè; Papi, Massimiliano

    2011-11-01

    Ischemic heart disease consists in the formation of an occluding thrombus which hinders blood flow. The dissolution of the network of fibrin fibers, which constitute the thrombus scaffold, by using thrombolitic drugs is the most common pharmacological therapy. In this paper, by using small angle neutron scattering, we report the evidence of the presence of solvent filled cylindrical nanocavities, trapped along fibrin fibers, of diameter R = 3.2 ± 0.1 nm and length L = 22 ± 2 nm. The characterization of intra-fiber nanocavities furnishes a quantitative tool for the design of new enzymes which, by diffusing into fibrin fibers, fasten the thrombus lysis.

  15. Alignment of the Fibrin Network Within an Autologous Plasma Clot.

    PubMed

    Gessmann, Jan; Seybold, Dominik; Peter, Elvira; Schildhauer, Thomas Armin; Köller, Manfred

    2016-01-01

    Autologous plasma clots with longitudinally aligned fibrin fibers could serve as a scaffold for longitudinal axonal regrowth in cases of traumatic peripheral nerve injuries. Three different techniques for assembling longitudinally oriented fibrin fibers during the fibrin polymerization process were investigated as follows: fiber alignment was induced by the application of either a magnetic field or-as a novel approach-electric field or by the induction of orientated flow. Fiber alignment was characterized by scanning electron microscopy analysis followed by image processing using fast Fourier transformation (FFT). Besides FFT output images, area xmin to xmax, as well as full width at half maximum (FWHM) of the FFT graph plot peaks, was calculated to determine the relative degree of fiber alignment. In addition, fluorescently labeled human fibrinogen and mesenchymal stem cells (MSCs) were used to visualize fibrin and cell orientation in aligned and nonaligned plasma clots. Varying degrees of fiber alignment were achieved by the three different methods, with the electric field application producing the highest degree of fiber alignment. The embedded MSCs showed a longitudinal orientation in the electric field-aligned plasma clots. The key feature of this study is the ability to produce autologous plasma clots with aligned fibrin fibers using physical techniques. This orientated internal structure of an autologous biomaterial is promising for distinct therapeutic applications, such as a guiding structure for cell migration and growth dynamics.

  16. The effect of fibrin sealant on the prevention of seroma formation after postbariatric abdominoplasty

    PubMed Central

    Lee, Johnson C; Teitelbaum, Jason; Shajan, Josh K; Naram, Aparajit; Chao, Jerome

    2012-01-01

    BACKGROUND: Seroma formation is one of the most common complications following abdominoplasty. Fibrin sealant/glue has shown mixed results in seroma prevention when used in a variety of procedures. Limited information is available on its effectiveness during postbariatric abdominoplasty. METHODS: A retrospective chart analysis of 65 consecutive patients who underwent postbariatric abdominoplasty over a course of 16 months by a single surgeon was performed. Two sequential groups either receiving or not receiving fibrin sealant treatment were defined. Seroma formation and initial 24 h drain output volumes were recorded. RESULTS: Three patients in group 1 (9.1%) receiving fibrin sealant developed seroma. Twelve patients in group 2 (28.1%) not receiving fibrin sealant developed seroma; this was statistically significant (P=0.006). Twenty-four hour drain output was also statistically different, with higher initial output in the fibrin sealant group (222.2 mL versus 140.0 mL; P=0.047). CONCLUSION: Fibrin sealant was a useful adjunct during surgical wound closure and significantly decreased seroma formation in patients undergoing postbariatric abdominoplasty. PMID:23997585

  17. [The use of tissue glue and its effect on hospital cost in patients undergoing pulmonary surgery].

    PubMed

    Gündoğdu, Ahmet Gökhan; Yazicioğlu, Alkin; Kara, Murat; Kanbak, Meral; Doğan, Riza

    2006-01-01

    Prolonged air leak following pulmonary resections is an important cause of morbidity and increased hospital costs. We compared 19 homologous/autologous tissue glue (fibrin glue) applied patients (FG group), 12 beriplast-P applied patients (beriplast group) and 27 control patients with respect to prolonged air leak, chest tube removal time and hospital costs. The mean ages for FG group (19 patients), beriplast group (12 patients) and control group (27 patients) were 48.5 +/- 14, 50.5 +/- 6.8 and 55 +/- 12.9 respectively. The groups were comparable with respect to age (p= 0.210), sex (p= 0.287) and the surgical procedure performed (p= 0.289). The incidence of prolonged air leak in FG group, beriplast group and the control group was 48%, 50% and 63%, respectively (p= 0.533). The mean chest tube removal time in FG group, beriplast group and the control group was 10.7 +/- 8.7, 9 +/- 4.1 and 8 +/- 3.1 days, respectively (p= 0.282). Mean hospital costs in FG group, beriplast group and the control group were 4633 +/- 3272 YTL, 4611 +/- 1583 YTL and 4015 +/- 911 YTL, respectively (p= 0.547). Fibrin glue had no effect on the incidence of prolonged air leak, chest tube removal time and hospital costs.

  18. Platelet rich fibrin: a new paradigm in periodontal regeneration.

    PubMed

    Kumar, R Vinaya; Shubhashini, N

    2013-09-01

    Among the great challenges facing clinical research is the development of bioactive surgical additives regulating inflammation and increasing healing. Although the use of fibrin adhesives and platelet-rich plasma (PRP) is well documented, they have their own limitations. Hence, reconstructive dental surgeons are looking for an "edge" that jump starts the healing process to maximize predictability as well as the volume of regenerated bone. Overcoming the restrictions related to the reimplantation of blood-derived products, a new family of platelet concentrate, which is neither a fibrin glue nor a classical platelet concentrate, was developed in France. This second generation platelet concentrate called platelet-rich fibrin (PRF), has been widely used to accelerate soft and hard tissue healing. Its advantages over the better known PRP include ease of preparation/application, minimal expense, and lack of biochemical modification (no bovine thrombin or anticoagulant is required). This article serves as an introduction to the PRF "concept" and its potential clinical applications with emphasis on periodontal regeneration.

  19. Glues Used in Airplane Parts

    NASA Technical Reports Server (NTRS)

    Allen, S W; Truax, T R

    1920-01-01

    This report was prepared for the National Advisory Committee for Aeronautics and presents the results of investigations conducted by the Forest Products Laboratory of the United States Forest Service on the manufacture, preparation, application, testing and physical properties of the different types of glues used in wood airplane parts.

  20. Enhanced Viability of Endothelial Colony Forming Cells in Fibrin Microbeads for Sensor Vascularization.

    PubMed

    Gandhi, Jarel K; Zivkovic, Lada; Fisher, John P; Yoder, Mervin C; Brey, Eric M

    2015-09-18

    Enhanced vascularization at sensor interfaces can improve long-term function. Fibrin, a natural polymer, has shown promise as a biomaterial for sensor coating due to its ability to sustain endothelial cell growth and promote local vascularization. However, the culture of cells, particularly endothelial cells (EC), within 3D scaffolds for more than a few days is challenging due to rapid loss of EC viability. In this manuscript, a robust method for developing fibrin microbead scaffolds for long-term culture of encapsulated ECs is described. Fibrin microbeads are formed using sodium alginate as a structural template. The size, swelling and structural properties of the microbeads were varied with needle gauge and composition and concentration of the pre-gel solution. Endothelial colony-forming cells (ECFCs) were suspended in the fibrin beads and cultured within a perfusion bioreactor system. The perfusion bioreactor enhanced ECFCs viability and genome stability in fibrin beads relative to static culture. Perfusion bioreactors enable 3D culture of ECs within fibrin beads for potential application as a sensor coating.

  1. Enhanced Viability of Endothelial Colony Forming Cells in Fibrin Microbeads for Sensor Vascularization

    PubMed Central

    Gandhi, Jarel K.; Zivkovic, Lada; Fisher, John P.; Yoder, Mervin C.; Brey, Eric M.

    2015-01-01

    Enhanced vascularization at sensor interfaces can improve long-term function. Fibrin, a natural polymer, has shown promise as a biomaterial for sensor coating due to its ability to sustain endothelial cell growth and promote local vascularization. However, the culture of cells, particularly endothelial cells (EC), within 3D scaffolds for more than a few days is challenging due to rapid loss of EC viability. In this manuscript, a robust method for developing fibrin microbead scaffolds for long-term culture of encapsulated ECs is described. Fibrin microbeads are formed using sodium alginate as a structural template. The size, swelling and structural properties of the microbeads were varied with needle gauge and composition and concentration of the pre-gel solution. Endothelial colony-forming cells (ECFCs) were suspended in the fibrin beads and cultured within a perfusion bioreactor system. The perfusion bioreactor enhanced ECFCs viability and genome stability in fibrin beads relative to static culture. Perfusion bioreactors enable 3D culture of ECs within fibrin beads for potential application as a sensor coating. PMID:26393602

  2. Fibrin Networks Support Recurring Mechanical Loads by Adapting their Structure across Multiple Scales.

    PubMed

    Kurniawan, Nicholas A; Vos, Bart E; Biebricher, Andreas; Wuite, Gijs J L; Peterman, Erwin J G; Koenderink, Gijsje H

    2016-09-01

    Tissues and cells sustain recurring mechanical loads that span a wide range of loading amplitudes and timescales as a consequence of exposure to blood flow, muscle activity, and external impact. Both tissues and cells derive their mechanical strength from fibrous protein scaffolds, which typically have a complex hierarchical structure. In this study, we focus on a prototypical hierarchical biomaterial, fibrin, which is one of the most resilient naturally occurring biopolymers and forms the structural scaffold of blood clots. We show how fibrous networks composed of fibrin utilize irreversible changes in their hierarchical structure at different scales to maintain reversible stress stiffening up to large strains. To trace the origin of this paradoxical resilience, we systematically tuned the microstructural parameters of fibrin and used a combination of optical tweezers and fluorescence microscopy to measure the interactions of single fibrin fibers for the first time, to our knowledge. We demonstrate that fibrin networks adapt to moderate strains by remodeling at the network scale through the spontaneous formation of new bonds between fibers, whereas they adapt to high strains by plastic remodeling of the fibers themselves. This multiscale adaptation mechanism endows fibrin gels with the remarkable ability to sustain recurring loads due to shear flows and wound stretching. Our findings therefore reveal a microscopic mechanism by which tissues and cells can balance elastic nonlinearity and plasticity, and thus can provide microstructural insights into cell-driven remodeling of tissues. PMID:27602730

  3. Platelet Rich Fibrin in Periodontal Regeneration

    PubMed Central

    Arunachalam, Muthukumaraswamy; Pulikkotil, Shaju J.; Sonia, Nath

    2016-01-01

    Periodontitis is a chronic bacterial infection resulting in destruction of the supporting structures of the teeth. Regeneration of the lost tissues has faced difficulties primarily due to the lack of support during the intricate healing processes. A surgical additive which can ‘jump start’ the healing process to a more predictable regenerative process is always on the wish list of any periodontist. Platelet-rich fibrin (PRF) is a second generation platelet concentrate that has been considered to be an important, easy to obtain, predictable surgical additive for periodontal regeneration. This autologous scaffold provides the much needed bio-chemical mediators which has the potential for enhancing reconstruction of the periodontium. This review article tries to understand as to why PRF would be an important link to reach predictable periodontal regeneration. PMID:27386002

  4. Platelet Rich Fibrin in Periodontal Regeneration.

    PubMed

    Arunachalam, Muthukumaraswamy; Pulikkotil, Shaju J; Sonia, Nath

    2016-01-01

    Periodontitis is a chronic bacterial infection resulting in destruction of the supporting structures of the teeth. Regeneration of the lost tissues has faced difficulties primarily due to the lack of support during the intricate healing processes. A surgical additive which can 'jump start' the healing process to a more predictable regenerative process is always on the wish list of any periodontist. Platelet-rich fibrin (PRF) is a second generation platelet concentrate that has been considered to be an important, easy to obtain, predictable surgical additive for periodontal regeneration. This autologous scaffold provides the much needed bio-chemical mediators which has the potential for enhancing reconstruction of the periodontium. This review article tries to understand as to why PRF would be an important link to reach predictable periodontal regeneration. PMID:27386002

  5. Successful Closure of A Bronchopleural Fistula by Intrapleural Administration of Fibrin Sealant: A Case Report With Review of Literature

    PubMed Central

    Shrestha, Pranabh; Safdar, Syed Aatif; Jawad, Sami Abdul; Shaaban, Hamid; Dieguez, Javier; Elberaqdar, Enas; Rai, Srijana; Adelman, Marc

    2014-01-01

    Context: There are no established guidelines for the proper treatment of patients with bronchopleural fistulas (BPFs). Apart from attempts to close the fistula, emphasis of treatment and management is placed on preventive measures, early administration of antibiotics, drainage of the empyema and aggressive nutritional and rehabilitative support. Case Report: A 53-year-old male presented with nausea, vomiting, and dry cough with eventual respiratory failure. He was found to have an empyema of the left hemithorax which was managed with thoracostomy drainage and antibiotics. However, he had persistent air leak through the chest tube due to a BPF. Bronchoscopy failed to localize the involved segment. Application of fibrin glue through the chest tube succeeded in completely sealing the leak. Conclusion: To our knowledge, this is the first case report in which fibrin glue was successfully used intrapleurally to close a BPF related to an empyema. PMID:25317397

  6. Generation of a Fibrin Based Three-Layered Skin Substitute

    PubMed Central

    Kober, Johanna; Gugerell, Alfred; Schmid, Melanie; Kamolz, Lars-Peter; Keck, Maike

    2015-01-01

    A variety of skin substitutes that restore epidermal and dermal structures are currently available on the market. However, the main focus in research and clinical application lies on dermal and epidermal substitutes whereas the development of a subcutaneous replacement (hypodermis) is often disregarded. In this study we used fibrin sealant as hydrogel scaffold to generate a three-layered skin substitute. For the hypodermal layer adipose-derived stem cells (ASCs) and mature adipocytes were embedded in the fibrin hydrogel and were combined with another fibrin clot with fibroblasts for the construction of the dermal layer. Keratinocytes were added on top of the two-layered construct to form the epidermal layer. The three-layered construct was cultivated for up to 3 weeks. Our results show that ASCs and fibroblasts were viable, proliferated normally, and showed physiological morphology in the skin substitute. ASCs were able to differentiate into mature adipocytes during the course of four weeks and showed morphological resemblance to native adipose tissue. On the surface keratinocytes formed an epithelial-like layer. For the first time we were able to generate a three-layered skin substitute based on a fibrin hydrogel not only serving as a dermal and epidermal substitute but also including the hypodermis. PMID:26236715

  7. Generation of a Fibrin Based Three-Layered Skin Substitute.

    PubMed

    Kober, Johanna; Gugerell, Alfred; Schmid, Melanie; Kamolz, Lars-Peter; Keck, Maike

    2015-01-01

    A variety of skin substitutes that restore epidermal and dermal structures are currently available on the market. However, the main focus in research and clinical application lies on dermal and epidermal substitutes whereas the development of a subcutaneous replacement (hypodermis) is often disregarded. In this study we used fibrin sealant as hydrogel scaffold to generate a three-layered skin substitute. For the hypodermal layer adipose-derived stem cells (ASCs) and mature adipocytes were embedded in the fibrin hydrogel and were combined with another fibrin clot with fibroblasts for the construction of the dermal layer. Keratinocytes were added on top of the two-layered construct to form the epidermal layer. The three-layered construct was cultivated for up to 3 weeks. Our results show that ASCs and fibroblasts were viable, proliferated normally, and showed physiological morphology in the skin substitute. ASCs were able to differentiate into mature adipocytes during the course of four weeks and showed morphological resemblance to native adipose tissue. On the surface keratinocytes formed an epithelial-like layer. For the first time we were able to generate a three-layered skin substitute based on a fibrin hydrogel not only serving as a dermal and epidermal substitute but also including the hypodermis. PMID:26236715

  8. A new heterologous fibrin sealant as scaffold to recombinant human bone morphogenetic protein-2 (rhBMP-2) and natural latex proteins for the repair of tibial bone defects.

    PubMed

    Machado, Eduardo Gomes; Issa, João Paulo Mardegan; Figueiredo, Fellipe Augusto Tocchini de; Santos, Geovane Ribeiro Dos; Galdeano, Ewerton Alexandre; Alves, Mariana Carla; Chacon, Erivelto Luis; Ferreira Junior, Rui Seabra; Barraviera, Benedito; Cunha, Marcelo Rodrigues da

    2015-04-01

    Tissue engineering has special interest in bone tissue aiming at future medical applications Studies have focused on recombinant human bone morphogenetic protein-2 (rhBMP-2) and natural latex proteins due to the osteogenic properties of rhBMP-2 and the angiogenic characteristic of fraction 1 protein (P-1) extracted from the rubber tree Hevea brasiliensis. Furthermore, heterologous fibrin sealant (FS) has been shown as a promising alternative in regenerative therapies. The aim of this study was to evaluate these substances for the repair of bone defects in rats. A bone defect measuring 3mm in diameter was created in the proximal metaphysis of the left tibia of 60 rats and was implanted with rhBMP-2 or P-1 in combination with a new heterologous FS derived from snake venom. The animals were divided into six groups: control (unfilled bone defect), rhBMP-2 (defect filled with 5μg rhBMP-2), P-1 (defect filled with 5μg P-1), FS (defect filled with 8μg FS), FS/rhBMP-2 (defect filled with 8μg FS and 5μg rhBMP-2), FS/P-1 (defect filled with 8μg FS and 5μg P-1). The animals were sacrificed 2 and 6 weeks after surgery. The newly formed bone projected from the margins of the original bone and exhibited trabecular morphology and a disorganized arrangement of osteocyte lacunae. Immunohistochemical analysis showed intense expression of osteocalcin in all groups. Histometric analysis revealed a significant difference in all groups after 2 weeks (p<0.05), except for the rhBMP-2 and FS/rhBMP-2 groups (p>0.05). A statistically significant difference (p<0.05) was observed in all groups after 6 weeks in relation to the volume of newly formed bone in the surgical area. In conclusion, the new heterologous fibrin sealant was found to be biocompatible and the combination with rhBMP-2 showed the highest osteogenic and osteoconductive capacity for bone healing. These findings suggest a promising application of this combination in the regeneration surgery. PMID:25825118

  9. Lyophilized platelet-rich fibrin (PRF) promotes craniofacial bone regeneration through Runx2.

    PubMed

    Li, Qi; Reed, David A; Min, Liu; Gopinathan, Gokul; Li, Steve; Dangaria, Smit J; Li, Leo; Geng, Yajun; Galang, Maria-Therese; Gajendrareddy, Praveen; Zhou, Yanmin; Luan, Xianghong; Diekwisch, Thomas G H

    2014-05-14

    Freeze-drying is an effective means to control scaffold pore size and preserve its composition. The purpose of the present study was to determine the applicability of lyophilized Platelet-rich fibrin (LPRF) as a scaffold for craniofacial tissue regeneration and to compare its biological effects with commonly used fresh Platelet-rich fibrin (PRF). LPRF caused a 4.8-fold±0.4-fold elevation in Runt-related transcription factor 2 (Runx2) expression in alveolar bone cells, compared to a 3.6-fold±0.2-fold increase when using fresh PRF, and a more than 10-fold rise of alkaline phosphatase levels and mineralization markers. LPRF-induced Runx2 expression only occurred in alveolar bone and not in periodontal or dental follicle cells. LPRF also caused a 1.6-fold increase in osteoblast proliferation (p<0.001) when compared to fresh PRF. When applied in a rat craniofacial defect model for six weeks, LPRF resulted in 97% bony coverage of the defect, compared to 84% for fresh PRF, 64% for fibrin, and 16% without scaffold. Moreover, LPRF thickened the trabecular diameter by 25% when compared to fresh PRF and fibrin, and only LPRF and fresh PRF resulted in the formation of interconnected trabeculae across the defect. Together, these studies support the application of lyophilized PRF as a biomimetic scaffold for craniofacial bone regeneration and mineralized tissue engineering.

  10. Lyophilized platelet-rich fibrin (PRF) promotes craniofacial bone regeneration through Runx2.

    PubMed

    Li, Qi; Reed, David A; Min, Liu; Gopinathan, Gokul; Li, Steve; Dangaria, Smit J; Li, Leo; Geng, Yajun; Galang, Maria-Therese; Gajendrareddy, Praveen; Zhou, Yanmin; Luan, Xianghong; Diekwisch, Thomas G H

    2014-01-01

    Freeze-drying is an effective means to control scaffold pore size and preserve its composition. The purpose of the present study was to determine the applicability of lyophilized Platelet-rich fibrin (LPRF) as a scaffold for craniofacial tissue regeneration and to compare its biological effects with commonly used fresh Platelet-rich fibrin (PRF). LPRF caused a 4.8-fold±0.4-fold elevation in Runt-related transcription factor 2 (Runx2) expression in alveolar bone cells, compared to a 3.6-fold±0.2-fold increase when using fresh PRF, and a more than 10-fold rise of alkaline phosphatase levels and mineralization markers. LPRF-induced Runx2 expression only occurred in alveolar bone and not in periodontal or dental follicle cells. LPRF also caused a 1.6-fold increase in osteoblast proliferation (p<0.001) when compared to fresh PRF. When applied in a rat craniofacial defect model for six weeks, LPRF resulted in 97% bony coverage of the defect, compared to 84% for fresh PRF, 64% for fibrin, and 16% without scaffold. Moreover, LPRF thickened the trabecular diameter by 25% when compared to fresh PRF and fibrin, and only LPRF and fresh PRF resulted in the formation of interconnected trabeculae across the defect. Together, these studies support the application of lyophilized PRF as a biomimetic scaffold for craniofacial bone regeneration and mineralized tissue engineering. PMID:24830554

  11. Lyophilized Platelet-Rich Fibrin (PRF) Promotes Craniofacial Bone Regeneration through Runx2

    PubMed Central

    Li, Qi; Reed, David A.; Min, Liu; Gopinathan, Gokul; Li, Steve; Dangaria, Smit J.; Li, Leo; Geng, Yajun; Galang, Maria-Therese; Gajendrareddy, Praveen; Zhou, Yanmin; Luan, Xianghong; Diekwisch, Thomas G. H.

    2014-01-01

    Freeze-drying is an effective means to control scaffold pore size and preserve its composition. The purpose of the present study was to determine the applicability of lyophilized Platelet-rich fibrin (LPRF) as a scaffold for craniofacial tissue regeneration and to compare its biological effects with commonly used fresh Platelet-rich fibrin (PRF). LPRF caused a 4.8-fold ± 0.4-fold elevation in Runt-related transcription factor 2 (Runx2) expression in alveolar bone cells, compared to a 3.6-fold ± 0.2-fold increase when using fresh PRF, and a more than 10-fold rise of alkaline phosphatase levels and mineralization markers. LPRF-induced Runx2 expression only occurred in alveolar bone and not in periodontal or dental follicle cells. LPRF also caused a 1.6-fold increase in osteoblast proliferation (p < 0.001) when compared to fresh PRF. When applied in a rat craniofacial defect model for six weeks, LPRF resulted in 97% bony coverage of the defect, compared to 84% for fresh PRF, 64% for fibrin, and 16% without scaffold. Moreover, LPRF thickened the trabecular diameter by 25% when compared to fresh PRF and fibrin, and only LPRF and fresh PRF resulted in the formation of interconnected trabeculae across the defect. Together, these studies support the application of lyophilized PRF as a biomimetic scaffold for craniofacial bone regeneration and mineralized tissue engineering. PMID:24830554

  12. Fabrication and physical and biological properties of fibrin gel derived from human plasma

    NASA Astrophysics Data System (ADS)

    Zhao, Haiguang; Ma, Lie; Zhou, Jie; Mao, Zhengwei; Gao, Changyou; Shen, Jiacong

    2008-03-01

    The fast development of tissue engineering and regenerative medicine drives the old biomaterials, for example, fibrin glue, to find new applications in these areas. Aiming at developing a commercially available hydrogel for cell entrapment and delivery, in this study we optimized the fabrication and gelation conditions of fibrin gel. Fibrinogen was isolated from human plasma by a freeze-thaw circle. Gelation of the fibrinogen was accomplished by mixing with thrombin. Absorbance of the fibrinogen/thrombin mixture at 550 nm as a function of reaction time was monitored by UV-VIS spectroscopy. It was found that the clotting time is significantly influenced by the thrombin concentration and the temperature, while less influenced by the fibrinogen concentration. After freeze-drying, the fibrin gel was characterized by scanning electron microscopy (SEM), revealing fibrous microstructure. Thermal gravimetric analysis found that the degradation temperature of the crosslinked fibrin gel starts from 288 °C, which is about 30 °C higher than that of the fibrinogen. The hydrogel has an initial water-uptake ratio of ~50, decreased to 30-40 after incubation in water for 11 h depending on the thrombin concentration. The fibrin gels lost their weights in PBS very rapidly, while slowly in DMEM/fetal bovine serum and DMEM. In vitro cell culture found that human fibroblasts could normally proliferate in the fibrin gel with spreading morphology. In conclusion, the fibrin gel containing higher concentration of fibrinogen (20 mg ml-1) and thrombin (5 U ml-1) has suitable gelation time and handling properties, and thus is applicable as a delivery vehicle for cells such as fibroblasts.

  13. Closure of a Traumatic Esophagomediastinal Fistula in a Child by Endoscopic Fulguration and Fibrin Injection.

    PubMed

    Maizlin, Ilan Igor; Chen, Jerry S; Smith, Nicholas James; Rogers, David A

    2016-09-01

    Posttraumatic esophagomediastinal fistula is an uncommon clinical entity that warrants surgical awareness due to its life-threatening potential. Its management, especially in previously operated field, is controversial and several endoscopic methods are being proposed as alternatives. Ours is the first report of endoscopic fulguration and fibrin injection in successful closure of such fistula. A 9-year-old female sustained complete tracheoesophageal transection from a gunshot wound to the neck and underwent immediate primary repair. She presented nine months later with fevers and swelling over anterior neck. CT revealed air tracking posteriorly to the dorsal neck and inferiorly to the mediastinum. Considering difficulty of open surgical approach, endoscopic intervention was attempted. Posterior wall fistula was identified via microlaryngoscopy above the esophageal anastomosis. The fistula tract was de-epithelialized via a Bugbee fulgurating electrode and then sealed with fibrin glue. Consequent imaging studies demonstrated complete occlusion of the fistula. Posterior posttraumatic esophagomediastinal fistula presents a challenging scenario from a surgical standpoint, as it combines difficulty of safe approach, high rate of injury to surrounding structures, and significant postoperative recurrence rate. Endoscopic Bugbee fulguration and fibrin glue injection are a safe and effective alternative to the traditional approach. PMID:27670565

  14. Polyphosphate enhances fibrin clot structure

    PubMed Central

    Smith, Stephanie A.

    2008-01-01

    Polyphosphate, a linear polymer of inorganic phosphate, is present in platelet dense granules and is secreted on platelet activation. We recently reported that polyphosphate is a potent hemostatic regulator, serving to activate the contact pathway of blood clotting and accelerate factor V activation. Because polyphosphate did not alter thrombin clotting times, it appeared to exert all its procoagulant actions upstream of thrombin. We now report that polyphosphate enhances fibrin clot structure in a calcium-dependent manner. Fibrin clots formed in the presence of polyphosphate had up to 3-fold higher turbidity, had higher mass-length ratios, and exhibited thicker fibers in scanning electron micrographs. The ability of polyphosphate to enhance fibrin clot turbidity was independent of factor XIIIa activity. When plasmin or a combination of plasminogen and tissue plasminogen activators were included in clotting reactions, fibrin clots formed in the presence of polyphosphate exhibited prolonged clot lysis times. Release of polyphosphate from activated platelets or infectious microorganisms may play an important role in modulating fibrin clot structure and increasing its resistance to fibrinolysis. Polyphosphate may also be useful in enhancing the structure of surgical fibrin sealants. PMID:18544683

  15. Direct Spinal Ventral Root Repair following Avulsion: Effectiveness of a New Heterologous Fibrin Sealant on Motoneuron Survival and Regeneration

    PubMed Central

    Barbizan, Roberta; Seabra Ferreira, Rui

    2016-01-01

    Axonal injuries at the interface between central and peripheral nervous system, such as ventral root avulsion (VRA), induce important degenerative processes, mostly resulting in neuronal and motor function loss. In the present work, we have compared two different fibrin sealants, one derived from human blood and another derived from animal blood and Crotalus durissus terrificus venom, as a promising treatment for this type of injury. Lewis rats were submitted to VRA (L4–L6) and had the avulsed roots reimplanted to the surface of the spinal cord, with the aid of fibrin sealant. The spinal cords were processed to evaluate neuronal survival, synaptic stability, and glial reactivity, 4 and 12 weeks after lesion. Sciatic nerves were processed to investigate Schwann cell activity by p75NTR expression (4 weeks after surgery) and to count myelinated axons and morphometric evaluation (12 weeks after surgery). Walking track test was used to evaluate gait recovery, up to 12 weeks. The results indicate that both fibrin sealants are similarly efficient. However, the snake-derived fibrin glue is a potentially safer alternative for being a biological and biodegradable product which does not contain human blood derivatives. Therefore, the venom glue can be a useful tool for the scientific community due to its advantages and variety of applications.

  16. Direct Spinal Ventral Root Repair following Avulsion: Effectiveness of a New Heterologous Fibrin Sealant on Motoneuron Survival and Regeneration

    PubMed Central

    Barbizan, Roberta; Seabra Ferreira, Rui

    2016-01-01

    Axonal injuries at the interface between central and peripheral nervous system, such as ventral root avulsion (VRA), induce important degenerative processes, mostly resulting in neuronal and motor function loss. In the present work, we have compared two different fibrin sealants, one derived from human blood and another derived from animal blood and Crotalus durissus terrificus venom, as a promising treatment for this type of injury. Lewis rats were submitted to VRA (L4–L6) and had the avulsed roots reimplanted to the surface of the spinal cord, with the aid of fibrin sealant. The spinal cords were processed to evaluate neuronal survival, synaptic stability, and glial reactivity, 4 and 12 weeks after lesion. Sciatic nerves were processed to investigate Schwann cell activity by p75NTR expression (4 weeks after surgery) and to count myelinated axons and morphometric evaluation (12 weeks after surgery). Walking track test was used to evaluate gait recovery, up to 12 weeks. The results indicate that both fibrin sealants are similarly efficient. However, the snake-derived fibrin glue is a potentially safer alternative for being a biological and biodegradable product which does not contain human blood derivatives. Therefore, the venom glue can be a useful tool for the scientific community due to its advantages and variety of applications. PMID:27642524

  17. Direct Spinal Ventral Root Repair following Avulsion: Effectiveness of a New Heterologous Fibrin Sealant on Motoneuron Survival and Regeneration.

    PubMed

    Vidigal de Castro, Mateus; Barbizan, Roberta; Seabra Ferreira, Rui; Barraviera, Benedito; Leite Rodrigues de Oliveira, Alexandre

    2016-01-01

    Axonal injuries at the interface between central and peripheral nervous system, such as ventral root avulsion (VRA), induce important degenerative processes, mostly resulting in neuronal and motor function loss. In the present work, we have compared two different fibrin sealants, one derived from human blood and another derived from animal blood and Crotalus durissus terrificus venom, as a promising treatment for this type of injury. Lewis rats were submitted to VRA (L4-L6) and had the avulsed roots reimplanted to the surface of the spinal cord, with the aid of fibrin sealant. The spinal cords were processed to evaluate neuronal survival, synaptic stability, and glial reactivity, 4 and 12 weeks after lesion. Sciatic nerves were processed to investigate Schwann cell activity by p75(NTR) expression (4 weeks after surgery) and to count myelinated axons and morphometric evaluation (12 weeks after surgery). Walking track test was used to evaluate gait recovery, up to 12 weeks. The results indicate that both fibrin sealants are similarly efficient. However, the snake-derived fibrin glue is a potentially safer alternative for being a biological and biodegradable product which does not contain human blood derivatives. Therefore, the venom glue can be a useful tool for the scientific community due to its advantages and variety of applications. PMID:27642524

  18. Glue: Linked data visualizations across multiple files

    NASA Astrophysics Data System (ADS)

    Beaumont, Chris; Robitaille, Thomas; Borkin, Michelle

    2014-02-01

    Glue, written in Python, links visualizations of scientific datasets across many files, allowing for interactive, linked statistical graphics of multiple files. It supports many file formats including common image formats (jpg, tiff, png), ASCII tables, astronomical image and table formats (FITS, VOT, IPAC), and HDF5. Custom data loaders can also be easily added. Glue is highly scriptable and extendable.

  19. The α-Helix to β-Sheet Transition in Stretched and Compressed Hydrated Fibrin Clots

    PubMed Central

    Litvinov, Rustem I.; Faizullin, Dzhigangir A.; Zuev, Yuriy F.; Weisel, John W.

    2012-01-01

    Fibrin is a protein polymer that forms the viscoelastic scaffold of blood clots and thrombi. Despite the critical importance of fibrin deformability for outcomes of bleeding and thrombosis, the structural origins of the clot’s elasticity and plasticity remain largely unknown. However, there is substantial evidence that unfolding of fibrin is an important part of the mechanism. We used Fourier transform infrared spectroscopy to reveal force-induced changes in the secondary structure of hydrated fibrin clots made of human blood plasma in vitro. When extended or compressed, fibrin showed a shift of absorbance intensity mainly in the amide I band (1600–1700 cm−1) as well as in the amide II and III bands, indicating an increase of the β-sheets and a corresponding reduction of the α-helices. The structural conversions correlated directly with the strain or pressure and were partially reversible at the conditions applied. The additional absorbance observed at 1612–1624 cm−1 was characteristic of the nascent interchain β-sheets, consistent with protein aggregation and fiber bundling during clot deformation observed using scanning electron microscopy. We conclude that under extension and/or compression an α-helix to β-sheet conversion of the coiled-coils occurs in the fibrin clot as a part of forced protein unfolding. PMID:23009851

  20. The Use Fibrin Sealant after Spinal Intradural Tumor Surgery: Is It Necessary?

    PubMed Central

    Won, Young Il; Chung, Chun Kee; Jahng, Tae-Ahn; Park, Sung Bae

    2016-01-01

    Objective A fibrin sealant is commonly applied after closure of an incidental or intended durotomy to reduce the complications associated with the leakage of cerebrospinal fluid. Routine usage might not be essential after closure of an intended durotomy, which has clear cut-margins. We investigated the efficacy of fibrin sealants for primary intradural spinal cord tumor surgery. Methods A retrospective review was performed for 231 consecutive surgically treated patients with primary intradural spinal cord tumors without extradural extension. Fibrin sealants were not used for 47 patients (group I: age, 51.57±16.75 years) and were applied to 184 patients (group II: age, 48.8±14.7 years). The surgical procedures were identical except for the use of a fibrin sealant after closure of the durotomy. The primary outcome was the occurrence of complications (wound problems, hematoma collection, infection, and neurological deterioration). The covariates were age, sex, body mass index, operation time, pre-/postoperative ambulation, number of laminectomies, and type of tumor. Results Schwannoma was the most common pathology (n=134), followed by meningioma (n=35) and ependymoma (n=31). Complications occurred in 13 patients (3 in group I and 10 in group II, p=0.73). The postoperative ambulation status (p<0.01; odds ratio, 28.8; 95% confidence interval, 6.9-120.0) and operation time (p=0.04; cutoff, 229 minutes; sensitivity, 62%; specificity, 72%) were significant factors, whereas the use of a fibrin glue was not (p=0.47). Conclusion The use of a fibrin sealant might not be essential to reduce complications after surgery for primary spinal intradural tumor. PMID:27123027

  1. ERK Signals: Scaffolding Scaffolds?

    PubMed Central

    Casar, Berta; Crespo, Piero

    2016-01-01

    ERK1/2 MAP Kinases become activated in response to multiple intra- and extra-cellular stimuli through a signaling module composed of sequential tiers of cytoplasmic kinases. Scaffold proteins regulate ERK signals by connecting the different components of the module into a multi-enzymatic complex by which signal amplitude and duration are fine-tuned, and also provide signal fidelity by isolating this complex from external interferences. In addition, scaffold proteins play a central role as spatial regulators of ERKs signals. In this respect, depending on the subcellular localization from which the activating signals emanate, defined scaffolds specify which substrates are amenable to be phosphorylated. Recent evidence has unveiled direct interactions among different scaffold protein species. These scaffold-scaffold macro-complexes could constitute an additional level of regulation for ERK signals and may serve as nodes for the integration of incoming signals and the subsequent diversification of the outgoing signals with respect to substrate engagement. PMID:27303664

  2. Fibrin Sealant and Lipoabdominoplasty in Obese Grade 1 and 2 Patients

    PubMed Central

    Mabrouk, Amr Abdel Wahab; Al Mekkawy, Soha Fathy; Mahmoud, Nada Abdel Sattar; Abdel-Salam, Ahmed Mohamed

    2013-01-01

    Background Ever since lipoabdominoplasty was first developed to achieve better aesthetic outcomes and less morbidity, the rate of seroma formation, especially in obese patients, has disturbed plastic surgeons. The aim of this study was to evaluate the effect of fibrin sealant in the prevention of seroma formation after lipoabdominoplasty in obese patients. Methods Sixty patients with a body mass index (BMI) between 30 and 39.9 were assigned randomly to 1 of 2 groups (30 patients each). Group A underwent lipoabdominoplasty with fibrin glue, while group B underwent traditional lipoabdominoplasty; both had closed suction drainage applied to the abdomen. The patients' demographics and postoperative complications were recorded. Seroma was detected using abdominal ultrasound examinations at two postoperative periods: between postoperative days 10 and 12 and, between postoperative days 18 and 21. Results The age range was 31 to 55 years (38.5±9.5 years) in group A and 25 to 58 years (37.8±9.1 years) in group B, while the mean BMI was 31.4 to 39.9 kg/m2 (32.6 kg/m2) in group A and 32.7 to 37.4 kg/m2 (31.5 kg/m2) in group B. In group A, the patients had a complication rate of 10% in group A versus 43% in group B (P<0.05). The incidence of seroma formation was 3% in the fibrin glue group but 37% in the lipoabdominoplasty-alone group (P<0.05). Conclusions Lipoabdominoplasty with the use of autologous fibrin sealant is a very effective method that significantly reduces the rate of postoperative seroma. PMID:24086820

  3. Surface properties of fibrinogen and fibrin.

    PubMed

    van Oss, C J

    1990-08-01

    By contact angle measurements on layers of fibrinogen and fibrin, it can be shown that the transformation from fibrinogen to fibrin is accompanied by a change in surface properties from very hydrophilic (fibrinogen) to moderately but definitely hydrophobic (fibrin). It is also shown that, contrary to serum albumin and gamma globulin, fibrinogen does not become more hydrophobic upon drying.

  4. Glue granuloma following laparoscopic hernia repair.

    PubMed

    Ihedioha, U; Panteleimonitis, S; Mann, C; Finch, G J

    2014-05-01

    Minimal inflammation of tissues can occur following skin closure with a foreign material. This foreign body reaction can lead to granuloma formation. We report the case of a middle-aged man who, having undergone laparoscopic surgery and had the port site wounds closed with skin glue, was detected to have a non-healing wound. A crystal mass protruding from the incision site was confirmed histologically as a chronic granulomatous reaction to skin glue. A foreign body granulomatous reaction to skin glue has not been described in the literature. PMID:24700107

  5. Glue granuloma following laparoscopic hernia repair.

    PubMed

    Ihedioha, U; Panteleimonitis, S; Mann, C; Finch, G J

    2014-05-01

    Minimal inflammation of tissues can occur following skin closure with a foreign material. This foreign body reaction can lead to granuloma formation. We report the case of a middle-aged man who, having undergone laparoscopic surgery and had the port site wounds closed with skin glue, was detected to have a non-healing wound. A crystal mass protruding from the incision site was confirmed histologically as a chronic granulomatous reaction to skin glue. A foreign body granulomatous reaction to skin glue has not been described in the literature.

  6. Glue Film Thickness Measurements by Spectral Reflectance

    SciTech Connect

    B. R. Marshall

    2010-09-20

    Spectral reflectance was used to determine the thickness of thin glue layers in a study of the effect of the glue on radiance and reflectance measurements of shocked-tin substrates attached to lithium fluoride windows. Measurements based on profilometry of the components were found to be inaccurate due to flatness variations and deformation of the tin substrate under pressure during the gluing process. The accuracy of the spectral reflectance measurements were estimated to be ±0.5 μm, which was sufficient to demonstrate a convincing correlation between glue thickness and shock-generated light.

  7. A novel composite construct increases the vascularization potential of PEG hydrogels through the incorporation of large fibrin ribbons

    PubMed Central

    Mason, Mariah N.; Mahoney, Melissa J.

    2010-01-01

    Developing a mechanism to vascularize tissue engineered constructs is imperative for transplant function and integration, particularly when delivering hypoxia-sensitive tissues such as pancreatic islets. Previous efforts have focused on bulk modifications of scaffold materials rendering the entire construct permissive to vessel penetration or the formation of a porous structure where vessels can infiltrate the empty spaces. Here we describe a novel construct composed of large fibrin ribbons encapsulated within a poly(ethylene glycol) (PEG) hydrogel. The PEG/fibrin ribbon composite scaffold facilitates co-culture of adhesive and non-adhesive cell types, thus providing closely neighboring environments with distinct material properties specific to the needs of two clinically relevant cell populations. This advantage is demonstrated here by the successful co-culture of pancreatic islets in the PEG component and vessel-forming endothelial cells in entrapped fibrin ribbons. Transplanted endothelial cells can form anastomosies with host vasculature, suggesting that our co-cultures may lead to more rapid scaffold vascularization. Additionally, we show that surface-seeded endothelial cells form multicellular projections that migrate into non-adhesive PEG hydrogels along permissive fibrin ribbons, further demonstrating composite construct vascularization potential. Distribution of large fibrin ribbons throughout PEG hydrogels provide a potential mechanism for vascularization of a well-established biomaterial without inherently changing its desirable properties. PMID:20607870

  8. The mechanics of fibrin networks and their alterations by platelets

    NASA Astrophysics Data System (ADS)

    Jawerth, Louise Marie

    Fibrin is a biopolymer that assembles into a network during blood coagulation to become the structural scaffold of a blood clot. The precise mechanics of this network are crucial for a blood clot to properly stem the flow of blood at the site of vascular injury while still remaining pliable enough to avoid dislocation. A hallmark of fibrin's mechanical response is strain-stiffening: at small strains, its response is low and linear; while at high strains, its stiffness increases non-linearly with increasing strain. The physical origins of strain-stiffening have been studied for other biopolymer systems but have remained elusive for biopolymer networks composed of stiff filaments, such as fibrin. To understand the origins of this intriguing behavior, we directly observe and quantify the motion of all of the fibers in the fibrin networks as they undergo shear in 3D using confocal microscopy. We show that the strain-stiffening response of a clot is a result of the full network deformation rather than an intrinsic strain-stiffening response of the individual fibers. We observe a distinct transition from a linear, low-strain regime, where all fibers avoid any internal stretching, to a non-linear, high-strain regime, where an increasing number of fibers become stretched. This transition is characterized by a high degree of non-affine motion. Moreover, we are able to precisely calculate the non-linear stress-strain response of the network by using the strains on each fiber measured directly with confocal microscopy and by assuming the fibers behave like linearly elastic beams. This result confirms that it is the network deformation that causes the strain-stiffening behavior of fibrin clots. These data are consistent with predictions for low-connectivity networks with soft, bending, or floppy modes. Moreover, we show that the addition of small contractile cells, platelets, increases the low-strain stiffness of the network while the high-strain stiffness is independent of

  9. Spiders Tune Glue Viscosity to Maximize Adhesion.

    PubMed

    Amarpuri, Gaurav; Zhang, Ci; Diaz, Candido; Opell, Brent D; Blackledge, Todd A; Dhinojwala, Ali

    2015-11-24

    Adhesion in humid conditions is a fundamental challenge to both natural and synthetic adhesives. Yet, glue from most spider species becomes stickier as humidity increases. We find the adhesion of spider glue, from five diverse spider species, maximizes at very different humidities that matches their foraging habitats. By using high-speed imaging and spreading power law, we find that the glue viscosity varies over 5 orders of magnitude with humidity for each species, yet the viscosity at maximal adhesion for each species is nearly identical, 10(5)-10(6) cP. Many natural systems take advantage of viscosity to improve functional response, but spider glue's humidity responsiveness is a novel adaptation that makes the glue stickiest in each species' preferred habitat. This tuning is achieved by a combination of proteins and hygroscopic organic salts that determines water uptake in the glue. We therefore anticipate that manipulation of polymer-salts interaction to control viscosity can provide a simple mechanism to design humidity responsive smart adhesives.

  10. Spiders Tune Glue Viscosity to Maximize Adhesion.

    PubMed

    Amarpuri, Gaurav; Zhang, Ci; Diaz, Candido; Opell, Brent D; Blackledge, Todd A; Dhinojwala, Ali

    2015-11-24

    Adhesion in humid conditions is a fundamental challenge to both natural and synthetic adhesives. Yet, glue from most spider species becomes stickier as humidity increases. We find the adhesion of spider glue, from five diverse spider species, maximizes at very different humidities that matches their foraging habitats. By using high-speed imaging and spreading power law, we find that the glue viscosity varies over 5 orders of magnitude with humidity for each species, yet the viscosity at maximal adhesion for each species is nearly identical, 10(5)-10(6) cP. Many natural systems take advantage of viscosity to improve functional response, but spider glue's humidity responsiveness is a novel adaptation that makes the glue stickiest in each species' preferred habitat. This tuning is achieved by a combination of proteins and hygroscopic organic salts that determines water uptake in the glue. We therefore anticipate that manipulation of polymer-salts interaction to control viscosity can provide a simple mechanism to design humidity responsive smart adhesives. PMID:26513350

  11. Serum aluminium levels in glue-sniffer adolescent and in glue containers.

    PubMed

    Akay, Cemal; Kalman, Süleyman; Dündaröz, Ruşen; Sayal, Ahmet; Aydin, Ahmet; Ozkan, Yalçin; Gül, Hüsamettin

    2008-05-01

    Glue sniffing is a serious medical problem among teenagers. Various chemical substances such as toluene and benzene containing glues have been reported to be toxic. It has been demonstrated that some toxic metals such as lead are elevated in the blood of solvent-addicted patients. Whereas aluminium is an element that has toxic effects on neurological, hematopoetic system and bone metabolism. We want to determine the serum levels of aluminium in glue-sniffer adolescents in comparison with healthy subjects. In addition, we compared aluminium levels of different commercial glue preparations (i.e. metal and plastic containers), to determine which type of container is better for less aluminium toxicity. We measured serum levels of aluminium in 37 glue-sniffer and 37 healthy subjects using atomic absorption spectrophotometry. The average duration of glue-sniffer was 3.8 +/- 0.8 years. We also measured aluminium levels of 10 commercial glue preparations that seven of them with metal and three with plastic containers. We found that serum levels of aluminium were 63.29 +/- 13.20 ng/ml and 36.7 +/- 8.60 ng/ml in glue-sniffer and in control subjects, respectively (P < 0.001). The average aluminium level in the glues was 8.6 +/- 3.24 ng/g in the preparations with metal containers, whereas 3.03 +/- 0.76 ng/g with plastic containers (P < 0.001). Therefore, to decrease the incidence of aluminium toxicity in glue-sniffers, it may be a good step to market of glue preparations in plastic instead of metal containers.

  12. Astrocytes: Everything but the glue

    PubMed Central

    Gonzalez-Perez, Oscar; Lopez-Virgen, Veronica; Quiñones-Hinojosa, Alfredo

    2015-01-01

    The current knowledge in neuroscience indicates that neural tissue has two major cell populations: neurons and glia (term derived from the Greek word for glue). Neuronal population is characterized by the capacity to produce action potentials, whereas glial cells are typically identified as the subordinate cell population of neurons. To date, this point of view has changed dramatically and growing evidence indicates that glial cells play a crucial role in normal mental functions and the pathogenesis of neurological diseases. Classically, glial cells include four major populations clearly discernible in the adult brain: astrocytes, oligodendrocytes, microglia cells and NG2 glia. Astrocytes, also referred as to astroglia, are by far the most abundant cell lineage in the adult brain. These cells are in close contact with several tissue components of the brain parenchyma including neurons, vasculature, extracellular matrix and other glial populations. Hence, the number and strategic position of astrocytes provide them with exceptional capacity for modulating multiple functions in the neural tissue. PMID:25938129

  13. Bioreactor Conditioning for Accelerated Remodeling of Fibrin-Based Tissue Engineered Heart Valves

    NASA Astrophysics Data System (ADS)

    Schmidt, Jillian Beth

    Fibrin is a promising scaffold material for tissue engineered heart valves, as it is completely biological, allows for engineered matrix alignment, and is able to be degraded and replaced with collagen by entrapped cells. However, the initial fibrin matrix is mechanically weak, and extensive in vitro culture is required to create valves with sufficient mechanical strength and stiffness for in vivo function. Culture in bioreactor systems, which provide cyclic stretching and enhance nutrient transport, has been shown to increase collagen production by cells entrapped in a fibrin scaffold, accelerating strengthening of the tissue and reducing the required culture time. In the present work, steps were taken to improve bioreactor culture conditions with the goal of accelerating collagen production in fibrin-based tissue engineered heart valves using two approaches: (i) optimizing the cyclic stretching protocol and (ii) developing a novel bioreactor system that permits transmural and lumenal flow of culture medium for improved nutrient transport. The results indicated that incrementally increasing strain amplitude cyclic stretching with small, frequent increments in strain amplitude was optimal for collagen production in our system. In addition, proof of concept studies were performed in the novel bioreactor system and increased cellularity and collagen deposition near the lumenal surface of the tissue were observed.

  14. Platelet-rich fibrin promotes periodontal regeneration and enhances alveolar bone augmentation.

    PubMed

    Li, Qi; Pan, Shuang; Dangaria, Smit J; Gopinathan, Gokul; Kolokythas, Antonia; Chu, Shunli; Geng, Yajun; Zhou, Yanmin; Luan, Xianghong

    2013-01-01

    In the present study we have determined the suitability of platelet-rich fibrin (PRF) as a complex scaffold for periodontal tissue regeneration. Replacing PRF with its major component fibrin increased mineralization in alveolar bone progenitors when compared to periodontal progenitors, suggesting that fibrin played a substantial role in PRF-induced osteogenic lineage differentiation. Moreover, there was a 3.6-fold increase in the early osteoblast transcription factor RUNX2 and a 3.1-fold reduction of the mineralization inhibitor MGP as a result of PRF application in alveolar bone progenitors, a trend not observed in periodontal progenitors. Subcutaneous implantation studies revealed that PRF readily integrated with surrounding tissues and was partially replaced with collagen fibers 2 weeks after implantation. Finally, clinical pilot studies in human patients documented an approximately 5 mm elevation of alveolar bone height in tandem with oral mucosal wound healing. Together, these studies suggest that PRF enhances osteogenic lineage differentiation of alveolar bone progenitors more than of periodontal progenitors by augmenting osteoblast differentiation, RUNX2 expression, and mineralized nodule formation via its principal component fibrin. They also document that PRF functions as a complex regenerative scaffold promoting both tissue-specific alveolar bone augmentation and surrounding periodontal soft tissue regeneration via progenitor-specific mechanisms.

  15. Acute fibrinous and organising pneumonia.

    PubMed

    Guimarães, Catarina; Sanches, Inês; Ferreira, Catarina

    2012-03-20

    Acute fibrinous and organising pneumonia (AFOP) was recently described as an unusual pattern of diffuse lung disease. Particular characteristics make the differential diagnosis with the well recognised clinical patterns of diffuse alveolar damage, cryptogenic organising pneumonia or eosinophilic pneumonia. The lack of hyaline membranes, the presence of intra-alveolar fibrin, absence of noticeable eosinophils and patchy distribution suggests that AFOP define a distinct histological pattern. The authors describe the case of a woman diagnosed with AFOP after surgical lung biopsy, in association with primary biliary cirrhosis. The patient presented dyspnoea, fatigue, dry cough and thoracic pain. The CT scan showed bilateral patchy infiltrates predominantly in the lower lobes. Flexible bronchoscopy and subsidiary techniques were inconclusive and biopsy through video-assisted thoracoscopic surgery led to anatomopathological diagnosis of AFOP. The patient is having a good clinical response to prednisone.

  16. Platelet-rich plasma (PRP) and Platelet-Rich Fibrin (PRF): surgical adjuvants, preparations for in situ regenerative medicine and tools for tissue engineering.

    PubMed

    Bielecki, Tomasz; Dohan Ehrenfest, David M

    2012-06-01

    The recent developement of platelet concentrate for surgical use is an evolution of the fibrin glue technologies used since many years. The initial concept of these autologous preparations was to concentrate platelets and their growth factors in a plasma solution, and to activate it into a fibrin gel on a surgical site, in order to improve local healing. These platelet suspensions were often called Platelet-Rich Plasma (PRP) like the platelet concentrate used in transfusion medicine, but many different technologies have in fact been developed; some of them are even no more platelet suspensions, but solid fibrin-based biomaterials called Platelet-Rich Fibrin (PRF). These various technologies were tested in many different clinical fields, particularly oral and maxillofacial surgery, Ear-Nose-Throat surgery, plastic surgery, orthopaedic surgery, sports medicine, gynecologic and cardiovascular surgery and ophthalmology. This field of research unfortunately suffers from the lack of a proper accurate terminology and the associated misunderstandings, and the literature on the topic is quite contradictory. Indeed, the effects of these preparations cannot be limited to their growth factor content: these products associate many actors of healing in synergy, such as leukocytes, fibrin matrix, and circulating progenitor cells, and are in fact as complex as blood itself. If platelet concentrates were first used as surgical adjuvants for the stimulation of healing (as fibrin glues enriched with growth factors), many applications for in situ regenerative medicine and tissue engineering were developed and offer a great potential. However, the future of this field is first dependent on his coherence and scientific clarity. The objectives of this article is to introduce the main definitions, problematics and perspectives that are described in this special issue of Current Pharmaceutical Biotechnology about platelet concentrates.

  17. The GlueX DIRC project

    DOE PAGES

    Stevens, J.; Barbosa, F.; Bessuille, J.; Chudakov, E.; Dzhygadlo, R.; Fanelli, C.; Frye, J.; Hardin, J.; Kelsey, J.; Patsyuk, M.; et al

    2016-07-20

    Here, the GlueX experiment was designed to search for and study the pattern of gluonic excitations in the meson spectrum produced through photoproduction reactions at a new tagged photon beam facility in Hall D at Jefferson Laboratory. The particle identification capabilities of the GlueX experiment will be enhanced by constructing a DIRC (Detection of Internally Reflected Cherenkov light) detector, utilizing components of the decommissioned BaBar DIRC. The DIRC will allow systematic studies of kaon final states that are essential for inferring the quark flavor content of both hybrid and conventional mesons. In this contribution, the design for the GlueX DIRCmore » will be discussed including new expansion volumes, read out with MaPMTs, that are currently under development.« less

  18. Hackable User Interfaces In Astronomy with Glue

    NASA Astrophysics Data System (ADS)

    Beaumont, C.; Goodman, A.; Greenfield, P.

    2015-09-01

    Astronomers typically choose between Graphical User Interfaces and custom-written computer code when exploring and analyzing data. Few tools are designed to encourage both of these workflows, despite their complementary strengths. We believe that such hybrid hackable user interfaces could enable more agile data exploration, combining the fluidity that comes from a GUI with the precision and reproducibility that comes from writing code. In this article we articulate the different strengths and weaknesses of both workflows and discuss how to enable both in a single tool. We focus on Glue (http://glue-viz.org) as a case study and examine how the goal of creating a hackable user interface has influenced the design of Glue.

  19. The GlueX DIRC project

    NASA Astrophysics Data System (ADS)

    Stevens, J.; Barbosa, F.; Bessuille, J.; Chudakov, E.; Dzhygadlo, R.; Fanelli, C.; Frye, J.; Hardin, J.; Kelsey, J.; Patsyuk, M.; Schwartz, C.; Schwiening, J.; Shepherd, M.; Whitlatch, T.; Williams, M.

    2016-07-01

    The GlueX experiment was designed to search for and study the pattern of gluonic excitations in the meson spectrum produced through photoproduction reactions at a new tagged photon beam facility in Hall D at Jefferson Laboratory. The particle identification capabilities of the GlueX experiment will be enhanced by constructing a DIRC (Detection of Internally Reflected Cherenkov light) detector, utilizing components of the decommissioned BaBar DIRC. The DIRC will allow systematic studies of kaon final states that are essential for inferring the quark flavor content of both hybrid and conventional mesons. The design for the GlueX DIRC is presented, including the new expansion volumes that are currently under development.

  20. Physics Prospects with GlueX

    SciTech Connect

    Alexander Somov

    2011-10-01

    The new experiment GlueX is being currently constructed at Jefferson Lab. The experiment was designed to search for hybrid mesons with exotic-quantum-numbers using a beam of linearly polarized photons incident on a liquid hydrogen target. We will discuss the discovery potential of the GlueX experiment and briefly overview its physics program. GlueX is a new experiment at Jefferson Lab. whose physics program is intended to improve our knowledge of strong interactions. The main goal of the experiment is to search for gluonic excitations in photoproduction. The experiment is expected to collect a data sample a few order of magnitudes larger than all existing photoproduction data. The physics topics of the experiment spans from light meson spectroscopy to Primakoff production of pseudoscalar mesons. The construction of the experiment has started in 2009 and the commissioning stage is expected to be finished in 2015.

  1. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... to detect fibrin monomer in the diagnosis of disseminated intravascular coagulation (nonlocalized... coagulation and primary fibrinolysis (dissolution of the fibrin in a blood clot). (b) Classification. Class...

  2. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... to detect fibrin monomer in the diagnosis of disseminated intravascular coagulation (nonlocalized... coagulation and primary fibrinolysis (dissolution of the fibrin in a blood clot). (b) Classification. Class...

  3. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... to detect fibrin monomer in the diagnosis of disseminated intravascular coagulation (nonlocalized... coagulation and primary fibrinolysis (dissolution of the fibrin in a blood clot). (b) Classification. Class...

  4. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... to detect fibrin monomer in the diagnosis of disseminated intravascular coagulation (nonlocalized... coagulation and primary fibrinolysis (dissolution of the fibrin in a blood clot). (b) Classification. Class...

  5. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... to detect fibrin monomer in the diagnosis of disseminated intravascular coagulation (nonlocalized... coagulation and primary fibrinolysis (dissolution of the fibrin in a blood clot). (b) Classification. Class...

  6. Antibacterial properties of propolis (bee glue).

    PubMed Central

    Grange, J M; Davey, R W

    1990-01-01

    Propolis (bee glue) was found to have antibacterial activity against a range of commonly encountered cocci and Gram-positive rods, including the human tubercle bacillus, but only limited activity against Gram-negative bacilli. These findings confirm previous reports of antimicrobial properties of this material, possibly attributable to its high flavonoid content. PMID:2182860

  7. Fibrin nanoconstructs: a novel processing method and their use as controlled delivery agents

    NASA Astrophysics Data System (ADS)

    Praveen, G.; Sreerekha, P. R.; Menon, Deepthy; Nair, Shantikumar V.; Prasad Chennazhi, Krishna

    2012-03-01

    Fibrin nanoconstructs (FNCs) were prepared through a modified water-in-oil emulsification-diffusion route without the use of any surfactants, resulting in a high yield synthesis of fibrin nanotubes (FNTs) and fibrin nanoparticles (FNPs). The fibrin nanoconstructs formed an aligned structure with self-assembled nanotubes with closed heads that eventually formed spherical nanoparticles of size ˜250 nm. The nanotubes were typically ˜700 nm long and 150-300 nm in diameter, with a wall thickness of ˜50 nm and pore diameter of about 150-250 nm. These constructs showed high stability against aggregation indicated by a zeta potential of -44 mV and an excellent temperature stability upto 200 °C. Furthermore, they were found to be enzymatically degradable, thereby precluding any long term toxicity effects. These unique fibrin nanostructures were analyzed for their ability to deliver tacrolimus, an immunosuppressive drug that is used widely to prevent the initial phase of tissue rejection during allogenic transplantation surgeries. Upon conjugation with tacrolimus, a drug encapsulation efficiency of 66% was achieved, with the in vitro release studies in PBS depicting a sustained and complete drug release over a period of one week at the physiological pH of 7.4. At a more acidic pH, the drug release was very slow, suggesting their potential for oral-intestinal drug administration as well. The in vivo drug absorption rates analyzed in Sprague Dawley rats further confirmed the sustained release pattern of tacrolimus for both oral and parenteral delivery routes. The novel fibrin nanoconstructs developed using a green chemistry approach thus proved to be excellent biodegradable nanocarriers for oral as well as parenteral administrations, with remarkable potential also for delivering specific growth factors in tissue engineering scaffolds.

  8. High-throughput proteomic characterization of plasma rich in growth factors (PRGF-Endoret)-derived fibrin clot interactome.

    PubMed

    Anitua, Eduardo; Prado, Roberto; Azkargorta, Mikel; Rodriguez-Suárez, Eva; Iloro, Ibon; Casado-Vela, Juan; Elortza, Felix; Orive, Gorka

    2015-11-01

    Plasma rich in growth factors (PRGF®-Endoret®) is an autologous technology that contains a set of proteins specifically addressed to wound healing and tissue regeneration. The scaffold formed by using this technology is a clot mainly composed of fibrin protein, forming a three-dimensional (3D) macroscopic network. This biomaterial is easily obtained by biotechnological means from blood and can be used in a range of situations to help wound healing and tissue regeneration. Although the main constituent of this clot is the fibrin scaffold, little is known about other proteins interacting in this clot that may act as adjuvants in the healing process. The aim of this study was to characterize the proteins enclosed by PRGF-Endoret scaffold, using a double-proteomic approach that combines 1D-SDS-PAGE approach followed by LC-MS/MS, and 2-DE followed by MALDI-TOF/TOF. The results presented here provide a description of the catalogue of key proteins in close contact with the fibrin scaffold. The obtained lists of proteins were grouped into families and networks according to gene ontology. Taken together, an enrichment of both proteins and protein families specifically involved in tissue regeneration and wound healing has been found.

  9. Tracheal reconstruction using chondrocytes seeded on a poly(L-lactic-co-glycolic acid)-fibrin/hyaluronan.

    PubMed

    Hong, Hyun Jun; Chang, Jae Won; Park, Ju-Kyeong; Choi, Jae Won; Kim, Yoo Suk; Shin, Yoo Seob; Kim, Chul-Ho; Choi, Eun Chang

    2014-11-01

    Reconstruction of trachea is still a clinical dilemma. Tissue engineering is a recent and promising concept to resolve this problem. This study evaluated the feasibility of allogeneic chondrocytes cultured with fibrin/hyaluronic acid (HA) hydrogel and degradable porous poly(L-lactic-co-glycolic acid) (PLGA) scaffold for partial tracheal reconstruction. Chondrocytes from rabbit articular cartilage were expanded and cultured with fibrin/HA hydrogel and injected into a 5 × 10 mm-sized, curved patch-shape PLGA scaffold. After 4 weeks in vitro culture, the scaffold was implanted on a tracheal defect in eight rabbits. Six and 10 weeks postoperatively, the implanted sites were evaluated by bronchoscope and radiologic and histologic analyses. Ciliary beat frequency (CBF) of regenerated epithelium was also evaluated. None of the eight rabbits showed any sign of respiratory distress. Bronchoscopic examination did not reveal stenosis of the reconstructed trachea and the defects were completely recovered with respiratory epithelium. Computed tomography scan showed good luminal contour of trachea. Histologic data showed that the implanted chondrocytes successfully formed neocartilage with minimal granulation tissue. CBF of regenerated epithelium was similar to that of normal epithelium. Partial tracheal defect was successfully reconstructed anatomically and functionally using allogeneic chondrocytes cultured with PLGA-fibrin/HA composite scaffold.

  10. Summary of Glue Tests 1993

    SciTech Connect

    Bell, D.; /Fermilab

    1993-01-07

    I have reported most of the results of my adhesive testing to members of the VLPC design team at one time or another, usually verbally, but I am wnnng this summary as an easy reference to the results I obtained. The adhesives I tested were for two primary purposes. The first was adhering optical fibers to Torlon 7130; the other was for securing an aluminum nitride substrate to the same material. I have not had access to a scanning electron microscope and someone with the knowledge to determine actual failure mechanisms, so the deductions I have made about why some adhesives have worked well at low temperatures for some purposes and not for other applications while a different material never worked and another always worked are partially speculation. They should be taken merely at face value with no particular results 'carved in stone' so to speak. The first aspect of my testing was adhesion of optical fiber to torlon. Knowing that this is a very important joint, I tested a variety of glues of two primary types: acrylic and W cure. W cure adhesives are known to possess reasonably good properties at low temperatures and are quite convenient to use as long as a W source is available. The W cure adhesives I tested were: Loctite Utak 376 and also 7EN484(?), Master Bond 1 Component W 15-7, and Norland optical adhesive 61. I found them quite easy to use, and they were packaged in a way in which they were not likely to cause a mess. Lab 6 e Perimenters generally used the Loctite 376 optical cure adhesive in their research into connecting scintillating fibers to the standard type. The acrylics I tested were Loctite Speed Bonder 324 and Permabond Quick Bond 610. These worked reasonably well, but they require a considerably longer set time than the W cure adhesives and are more complicated to use. (5 minutes set time or so for the acrylics versus about 30 seconds for the W. The Loctite must have the activator applied about 5 minutes prior to the adhesive application and the

  11. Sutureless cataract incision closure using laser-activated tissue glues

    NASA Astrophysics Data System (ADS)

    Eaton, Alexander M.; Bass, Lawrence S.; Libutti, Steven K.; Schubert, Herman D.; Treat, Michael R.

    1991-06-01

    With the advent of phacoemulsification and foldable intraocular lenses, there is renewed interest in sutureless cataract wound. We report the use of laser activated tissue glues for the closure of scleral tunnel cataract incisions. Two glue mixtures were tested in enucleated porcine eyes. Glue A was composed of hyaluronic acid, human albumin, and indocyanine green dye. Glue B contained hyaluronic acid, chondroitin sulfate, human albumin, and indocyanine green dye. A Spectra Physics diode laser (808 nm) with a power density of 7-1 1 watts/cm2 was used for glue activation. Wound bursting pressures, as determined by the presence of fluid at the wound margin, was significantly higher with both glue combinations than without the glue (PGlue A was 69.9 17.1 mm Hg, and for Glue B was 42.9 9.4 mm Hg. These results suggest that laser activated tissue glues may be an alternative to suture closure of scleral tunnel cataract incisions.

  12. Making Glue: Participation in Everyday Computing

    NASA Astrophysics Data System (ADS)

    Martin, Karen

    Technology, it is suggested, has the potential to facilitate social interaction and act as "glue" in bringing individuals together. Understanding how technology might act as social glue relies on observation and analysis of people's interaction with the system in question. When technology is understood as one strand of a broader ecology that also includes social, spatial, economic, political, and cultural systems then this suggests that other factors may influence the participant's engagement with interactive systems. Here, two case studies are described to understand better as to how the construction of participation - tasks, participant choice, and means of evaluating success - affects the outcomes. This analysis suggests that, while these factors play a part in the participant's engagement, evaluating a technology in context may require collaboration between researchers and third-party facilitators. In this case, participation may be a result of negotiation rather than the a priori design of researchers.

  13. Cross-linking of fibrinogen and fibrin by fibrin-stablizing factor (factor XIIIa).

    PubMed

    Kanaide, H; Shainoff, J R

    1975-04-01

    Factor XIIIa catalyzed intermolecular cross-linking of fibrinogen at initial rates that varied in direct (first order) proportion to the fibrinogen concentration, which differed from the well known zero order relationship in fibrin cross-linking. Preferential cross-linking of gamma-chains occurred with both substrates. The differences in rates and order of reaction were attributed mainly to effect of self-alignment of the gamma-chains in fibrin which enabled the cross-linking enzyme to interact with paired chains as a single rather than two independent entities. Studies on mixtures of fibrinogen and fibrin indicated factor XIIIa had near equal affinities for the two substrates. At low concentrations with which cross-linking of fibrinogen proceeded sluggishly compared to fibrin, fibrinogen inhibited stabilization of fibrin clots by competitively partitioning factor XIIIa away from the fribin. Additional inhibition arose from cross-linking of fibrin in soluble combination with fibrinogen in mixtures containing fibrinogen in large excess over fibrin. The observations demonstrate ways in which fibrinogen normally helps to suppress both polymerization and cross-linking of small amounts of fibrin produced within the circulation. At very high concentrations above 30 mg. per milliliter, fibrinogen underwent cross-linking at faster initial rates than the cross-linking of fibrin. Rapid cross-linking of concentrated fibrogen raises the possibility that filtration enrichment may be a factor contributing to abnormal formation of the highly insoluble fibrinogen deposits occurring in atheromatous tissue.

  14. The Fixed Combination of Collagen With Components of Fibrin Adhesive—A New Hemostypic Agent in Skull Base Procedures

    PubMed Central

    Nistor, Raymond F.; Chiari, Friedrich M.; Maier, Heinz; Hehl, Klaus

    1997-01-01

    CSF leak still is one of the major sources of morbidity after extensive skull base procedures. Of the various standard closure techniques of traumatic or iatrogenic dural defects, none provides a really waterlight, persistent closure. Even the supplementary use of fluid fibrin glue did not substantially improve the rate of postoperative CSF leaks. The application of a collagen sheet covered with a fixed layer of solid components of a fibrin tissue glue (TachoComb®) overcomes the major drawbacks of dural sealing in skull base surgery. The dural defects of 58 patients undergoing extensive skull base procedures were sealed with this new hemostyptic agent. The series includes 44 patients undergoing primary surgery, 6 patients with traumatic or iatrogenic tears of venous sinuses, and 8 patients with postoperative leaks after previous skull base procedures in which other sealing methods were previously used. In the group of primary surgery, none of the patients had postoperative CSF leakage or venous rebleeding. One patient developed a delayed pneumatocephalus. All cases of patent CSF fistulas were resolved without any adjuvant therapy. Preliminary experience shows that the good sealing and hemostyptic performance of this new agent will considerably reduce the risk of postoperative CSF leak and infection after skull base procedures. ImagesFigure 2Figure 3Figure 4 PMID:17171003

  15. Structural hierarchy governs fibrin gel mechanics.

    PubMed

    Piechocka, Izabela K; Bacabac, Rommel G; Potters, Max; Mackintosh, Fred C; Koenderink, Gijsje H

    2010-05-19

    Fibrin gels are responsible for the mechanical strength of blood clots, which are among the most resilient protein materials in nature. Here we investigate the physical origin of this mechanical behavior by performing rheology measurements on reconstituted fibrin gels. We find that increasing levels of shear strain induce a succession of distinct elastic responses that reflect stretching processes on different length scales. We present a theoretical model that explains these observations in terms of the unique hierarchical architecture of the fibers. The fibers are bundles of semiflexible protofibrils that are loosely connected by flexible linker chains. This architecture makes the fibers 100-fold more flexible to bending than anticipated based on their large diameter. Moreover, in contrast with other biopolymers, fibrin fibers intrinsically stiffen when stretched. The resulting hierarchy of elastic regimes explains the incredible resilience of fibrin clots against large deformations.

  16. Multiple-Step Injection Molding for Fibrin-Based Tissue-Engineered Heart Valves.

    PubMed

    Weber, Miriam; Gonzalez de Torre, Israel; Moreira, Ricardo; Frese, Julia; Oedekoven, Caroline; Alonso, Matilde; Rodriguez Cabello, Carlos J; Jockenhoevel, Stefan; Mela, Petra

    2015-08-01

    Heart valves are elaborate and highly heterogeneous structures of the circulatory system. Despite the well accepted relationship between the structural and mechanical anisotropy and the optimal function of the valves, most approaches to create tissue-engineered heart valves (TEHVs) do not try to mimic this complexity and rely on one homogenous combination of cells and materials for the whole construct. The aim of this study was to establish an easy and versatile method to introduce spatial diversity into a heart valve fibrin scaffold. We developed a multiple-step injection molding process that enables the fabrication of TEHVs with heterogeneous composition (cell/scaffold material) of wall and leaflets without the need of gluing or suturing components together, with the leaflets firmly connected to the wall. The integrity of the valves and their functionality was proved by either opening/closing cycles in a bioreactor (proof of principle without cells) or with continuous stimulation over 2 weeks. We demonstrated the potential of the method by the two-step molding of the wall and the leaflets containing different cell lines. Immunohistology after stimulation confirmed tissue formation and demonstrated the localization of the different cell types. Furthermore, we showed the proof of principle fabrication of valves using different materials for wall (fibrin) and leaflets (hybrid gel of fibrin/elastin-like recombinamer) and with layered leaflets. The method is easy to implement, does not require special facilities, and can be reproduced in any tissue-engineering lab. While it has been demonstrated here with fibrin, it can easily be extended to other hydrogels.

  17. Multiple-Step Injection Molding for Fibrin-Based Tissue-Engineered Heart Valves

    PubMed Central

    Weber, Miriam; Gonzalez de Torre, Israel; Moreira, Ricardo; Frese, Julia; Oedekoven, Caroline; Alonso, Matilde; Rodriguez Cabello, Carlos J.

    2015-01-01

    Heart valves are elaborate and highly heterogeneous structures of the circulatory system. Despite the well accepted relationship between the structural and mechanical anisotropy and the optimal function of the valves, most approaches to create tissue-engineered heart valves (TEHVs) do not try to mimic this complexity and rely on one homogenous combination of cells and materials for the whole construct. The aim of this study was to establish an easy and versatile method to introduce spatial diversity into a heart valve fibrin scaffold. We developed a multiple-step injection molding process that enables the fabrication of TEHVs with heterogeneous composition (cell/scaffold material) of wall and leaflets without the need of gluing or suturing components together, with the leaflets firmly connected to the wall. The integrity of the valves and their functionality was proved by either opening/closing cycles in a bioreactor (proof of principle without cells) or with continuous stimulation over 2 weeks. We demonstrated the potential of the method by the two-step molding of the wall and the leaflets containing different cell lines. Immunohistology after stimulation confirmed tissue formation and demonstrated the localization of the different cell types. Furthermore, we showed the proof of principle fabrication of valves using different materials for wall (fibrin) and leaflets (hybrid gel of fibrin/elastin-like recombinamer) and with layered leaflets. The method is easy to implement, does not require special facilities, and can be reproduced in any tissue-engineering lab. While it has been demonstrated here with fibrin, it can easily be extended to other hydrogels. PMID:25654448

  18. Multiple-Step Injection Molding for Fibrin-Based Tissue-Engineered Heart Valves.

    PubMed

    Weber, Miriam; Gonzalez de Torre, Israel; Moreira, Ricardo; Frese, Julia; Oedekoven, Caroline; Alonso, Matilde; Rodriguez Cabello, Carlos J; Jockenhoevel, Stefan; Mela, Petra

    2015-08-01

    Heart valves are elaborate and highly heterogeneous structures of the circulatory system. Despite the well accepted relationship between the structural and mechanical anisotropy and the optimal function of the valves, most approaches to create tissue-engineered heart valves (TEHVs) do not try to mimic this complexity and rely on one homogenous combination of cells and materials for the whole construct. The aim of this study was to establish an easy and versatile method to introduce spatial diversity into a heart valve fibrin scaffold. We developed a multiple-step injection molding process that enables the fabrication of TEHVs with heterogeneous composition (cell/scaffold material) of wall and leaflets without the need of gluing or suturing components together, with the leaflets firmly connected to the wall. The integrity of the valves and their functionality was proved by either opening/closing cycles in a bioreactor (proof of principle without cells) or with continuous stimulation over 2 weeks. We demonstrated the potential of the method by the two-step molding of the wall and the leaflets containing different cell lines. Immunohistology after stimulation confirmed tissue formation and demonstrated the localization of the different cell types. Furthermore, we showed the proof of principle fabrication of valves using different materials for wall (fibrin) and leaflets (hybrid gel of fibrin/elastin-like recombinamer) and with layered leaflets. The method is easy to implement, does not require special facilities, and can be reproduced in any tissue-engineering lab. While it has been demonstrated here with fibrin, it can easily be extended to other hydrogels. PMID:25654448

  19. Thrombin interaction with fibrin polymerization sites.

    PubMed

    Hsieh, K

    1997-05-15

    Thrombin is central to hemostasis, and postclotting fibrinolysis and wound healing. During clotting, thrombin transforms plasma fibrinogen into polymerizing fibrin, which selectively adsorbs the enzyme into the clot. This protects thrombin from heparin-antithrombin inactivation, thus preserving the enzyme for postclotting events. To determine how the fibrin N-terminal polymerization sites of A alpha 17-23 (GPRVVER) and B beta 15-25 (GHRPLDKKREE) and their analogs may interact with thrombin, amidolysis vs. plasma- and fibrinogen-clotting assays were used to differentiate blockade of catalytic site vs. other thrombin domains. Amidolysis studies suggest GPRVVER inhibition of thrombin catalytic site through hydrophobic interaction, and GPRVVER inhibited clotting. Neither GPRP nor VVER nor the B beta 15-25 homologs inhibited amidolysis. Contrary to heparin, acyl-DKKREE promoted plasma-clotting, but inhibited fibrinogen-clotting. In addition, acyl-DKKREE reversed the anticoagulant effect of heparin (0.1 U/ml) in plasma. The results suggest fibrin B beta 15-25 interaction with thrombin, possibly by blocking the heparin-binding site. Together with the reported fibrin A alpha 27-50 binding to thrombin, polymerizing fibrin appears to initially bind to thrombin catalytic site and exosite-1 through A alpha 17-50, and to another thrombin site through B beta 15-25. As these fibrin sites are also involved in polymerization, competition of the polymerization process with thrombin-binding could subsequently dislodge thrombin from fibrin alpha-chain. This may re-expose the catalytic site and exosite-1, thus explaining the thrombogenicity of clot-bound thrombin. The implications of these findings in polymerization mechanism and anticoagulant design are discussed.

  20. Zinc modulates thrombin adsorption to fibrin

    SciTech Connect

    Hopmeier, P.; Halbmayer, M.; Fischer, M.; Marx, G. )

    1990-05-01

    Human thrombin with high affinity to Sepharose insolubilized fibrin monomers (high-affinity thrombin) was used to investigate the effect of Zn(II) on the thrombin adsorption to fibrin. Results showed that at Zn(II) concentrations exceeding 100 mumols/l, thrombin binding to fibrin was decreased concomitant with the Zn(II) concentration and time; at lower Zn(II) concentrations, thrombin adsorption was enhanced. Experimental results were identical by using 125I-labelled high-affinity alpha-thrombin or by measuring the thrombin activity either by chromogenic substrate or by a clotting time method. In contrast, Ca(II) alone (final conc. 3 mmol/l) or in combination with Zn(II) was not effective. However, at higher Ca(II) concentrations (7.5-15 mmol/l), thrombin adsorption was apparently decreased. Control experiments revealed that Zn(II) had no impact on the clottability of fibrinogen, and that the results of the experiments with Ca(II) were not altered by possible cross-linking of fibrin. We conclude that unlike Ca(II), Zn(II) is highly effective in modulating thrombin adsorption to fibrin.

  1. Changes in the Adhesive Properties of Spider Aggregate Glue During the Evolution of Cobwebs

    PubMed Central

    Sahni, Vasav; Blackledge, Todd A.; Dhinojwala, Ali

    2011-01-01

    We compare the prey capture glues produced by orb-weaving spiders (viscid glue) and their evolutionary descendents, the cobweb-weaving spiders (gumfoot glue). These glues are produced in homologous glands but exhibit contrasting structure, properties and response to changing humidity. Individual glue droplet stretching measurements indicate that the gumfoot glue behaves like a viscoelastic liquid in contrast to the viscid glue, which behaves like a viscoelastic solid. Moreover, the gumfoot glue is largely humidity-resistant – elasticity and adhesion are constant across variation in humidity and there is weak volume-dependence. Viscid glue, however, is highly humidity-sensitive. The glue expands an order of magnitude and demonstrates a monotonous reduction in elasticity under increased humidity, while glue adhesion optimizes at intermediate levels of humidity. We suggest that observed differences are due to different ‘tackifiers' used in these systems. These results shall inspire future efforts in fabricating stimuli-resistant and stimuli-sensitive materials. PMID:22355560

  2. GlueX: Meson Spectroscopy in Photoproduction

    SciTech Connect

    Salgado, Carlos; Smith, Elton S.

    2014-03-01

    The goal of the GlueX experiment \\cite{gluex} is to provide crucial data to help understand the soft gluonic fields responsible for binding quarks in hadrons. Hybrid mesons, and in particular exotic hybrid mesons, provide the ideal laboratory for testing QCD in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom. Photoproduction is expected to be effective in producing exotic hybrids but there is little data on the photoproduction of light mesons. GlueX will use the new 12-GeV electron beam at Jefferson Lab to produce a 9-GeV beam of linearly polarized photons using the technique of coherent bremsstrahlung. A solenoid-based hermetic detector is under construction, which will be used to collect data on meson production and decays. These data will also be used to study the spectrum of conventional mesons, including the poorly understood excited vector mesons. This talk will give an update on the experiment as well as describe theoretical developments \\cite{Dudek:2011bn} to help understand how these data can provide insights into the fundamental theory of strong interactions.

  3. The effect of synthetic oxygen carrier-enriched fibrin hydrogel on Schwann cells under hypoxia condition in vitro.

    PubMed

    Ma, Teng; Wang, Yuqing; Qi, Fengyu; Zhu, Shu; Huang, Liangliang; Liu, Zhongyang; Huang, Jinghui; Luo, Zhuojing

    2013-12-01

    Schwann cell (SC), which plays a key role in peripheral nerve regeneration, is one of the most classic supportive cells in neural tissue engineering. However, the biological activity of SCs seeded in nerve scaffolds decays subsequently due to local hypoxia induced by ischemia. Thus, we aimed to investigate whether a synthetic oxygen carrier-enriched fibrin gel would provide a sustained oxygen release to cultured SCs in vitro for overcoming a temporary (48 h) oxygen deprivation. In this study, perfluorotributylamine (PFTBA)-based oxygen carrying fibrin gel was prepared to provide oxygen for SCs under normoxic or hypoxic conditions. The dissolved oxygen within the culture media was measured by a blood-gas analyzer to quantify the time course of oxygen release from the PFTBA-enriched fibrin gel. SCs were cultured in the presence or absence of PFTBA-enriched fibrin gel under normoxic or hypoxic conditions. The tolerance of SCs to hypoxia was examined by a cell apoptosis assay. The growth of cells was characterized using S-100 staining and a CCK-8 assay. The migration of cells was examined using a Transwell chamber. The mRNA of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), glial cell derived neurotrophic factor (GDNF), neural cell adhesion molecule (N-CAM) and vascular endothelial growth factor (VEGF) in SCs were assayed by RT-PCR. In addition, SCs cultured in 3D PFTBA-enriched hydrogel were characterized by Live/Dead staining and the mRNA levels of BDNF, NGF, GDNF, N-CAM and VEGF were assayed by RT-PCR. The results showed that the PFTBA-enriched fibrin hydrogel was able to promote cell adhesion, migration, and proliferation under hypoxic conditions. Interestingly, PFTBA applied through the fibrin hydrogel dramatically enhanced the mRNA of BDNF, NGF, GDNF, N-CAM and VEGF under hypoxic condition. These findings highlight the possibility of enhancing nerve regeneration in cellular nerve grafts through PFTBA increased neurotropic secretion in SCs.

  4. Scaffolding and Metacognition

    ERIC Educational Resources Information Center

    Holton, Derek; Clarke, David

    2006-01-01

    This paper proposes an expanded conception of scaffolding with four key elements: (1) scaffolding agency--expert, reciprocal, and self-scaffolding; (2) scaffolding domain--conceptual and heuristic scaffolding; (3) the identification of self-scaffolding with metacognition; and (4) the identification of six zones of scaffolding activity; each zone…

  5. Hyaluronic acid and fibrin hydrogels with concentrated DNA/PEI polyplexes for local gene delivery.

    PubMed

    Lei, Yuguo; Rahim, Maha; Ng, Quinn; Segura, Tatiana

    2011-08-10

    Local delivery of DNA through a hydrogel scaffold would increase the applicability of gene therapy in tissue regeneration and cancer therapy. However, the delivery of DNA/cationic polymer nanoparticles (polyplexes) using hydrogels is challenging due to the aggregation and inactivation of polyplexes during their incorporation into hydrogel scaffolds. We developed a novel process (termed caged nanoparticle encapsulation or CnE) to load concentrated and unaggregated non-viral gene delivery nanoparticles into various hydrogels. Previously, we showed that PEG hydrogels loaded with DNA/PEI polyplexes through this process were able to deliver genes both in vitro and in vivo. In this study, we found that hyaluronic acid and fibrin hydrogels with concentrated and unaggregated polyplexes loaded through CnE were able to deliver genes in vivo as well, demonstrating the universality of the process.

  6. Bioinspired Nanoparticulate Medical Glues for Minimally Invasive Tissue Repair.

    PubMed

    Lee, Yuhan; Xu, Chenjie; Sebastin, Monisha; Lee, Albert; Holwell, Nathan; Xu, Calvin; Miranda Nieves, David; Mu, Luye; Langer, Robert S; Lin, Charles; Karp, Jeffrey M

    2015-11-18

    Delivery of tissue glues through small-bore needles or trocars is critical for sealing holes, affixing medical devices, or attaching tissues together during minimally invasive surgeries. Inspired by the granule-packaged glue delivery system of sandcastle worms, a nanoparticulate formulation of a viscous hydrophobic light-activated adhesive based on poly(glycerol sebacate)-acrylate is developed. Negatively charged alginate is used to stabilize the nanoparticulate surface to significantly reduce its viscosity and to maximize injectability through small-bore needles. The nanoparticulate glues can be concentrated to ≈30 w/v% dispersions in water that remain localized following injection. With the trigger of a positively charged polymer (e.g., protamine), the nanoparticulate glues can quickly assemble into a viscous glue that exhibits rheological, mechanical, and adhesive properties resembling the native poly(glycerol sebacate)-acrylate based glues. This platform should be useful to enable the delivery of viscous glues to augment or replace sutures and staples during minimally invasive procedures.

  7. A new approach for pancreatic tissue engineering: human endometrial stem cells encapsulated in fibrin gel can differentiate to pancreatic islet beta-cell.

    PubMed

    Niknamasl, Azadeh; Ostad, Seyed Nasser; Soleimani, Mansoureh; Azami, Mahmoud; Salmani, Maryam Kabir; Lotfibakhshaiesh, Nasrin; Ebrahimi-Barough, Somayeh; Karimi, Roya; Roozafzoon, Reza; Ai, Jafar

    2014-10-01

    Metabolic diabetes mellitus as the most serious and prevalent metabolic disease in the world has various complications. The most effective treatment of type I diabetes seems to be islet cell transplantation. Shortage of donors and difficult procedures and high rate of rejection have always restricted this approach. Tissue engineering is a novel effective solution to many medical problems such as diabetes. Endometrial mesenchymal stem cells as a lineage which have the potential to differentiate to mesodermal and endodermal tissues seem to be suitable for this purpose. Fibrin hydrogel with a high degree of biocompatibility and specific properties making it similar to normal pancreas seems to be an ideal scaffold. After successfully isolating stem cells (hEnSCs) from human endometrium, a three-step protocol was used to differentiate them into pancreatic beta cells. Fibrin was used as 3D scaffold. After 2 weeks, cells formed clusters like islets cells, and secretion of insulin was measured by chemiluminescence. PDX1, proinsulin, and c-peptide as special markers of β cells were detected by immunofluorescence. Expression of glucagon, PDX1, and insulin genes in mRNA level was detected by Real time PCR and gel electrophoresis. The former showed higher levels of gene expression in 3D cultures. SEM analysis showed good integrity between cells and scaffold. No toxicity was detected with fibrin scaffold by MTT assay.

  8. Haemophilia and advanced fibrin sealant technologies.

    PubMed

    Tock, B; Drohan, W; Hess, J; Pusateri, A; Holcomb, J; MacPhee, M

    1998-07-01

    Fibrin sealant, which consists mainly of fibrinogen and thrombin, provides rapid haemostasis as well as tissue sealing and adhesion. Commercial, viral-inactivated products are available in Europe, Canada, and Japan. Liquid fibrin sealant (LFS) has been used clinically in haemophiliacs to perform dental procedures, orthopedic surgeries, non-orthopaedic surgeries, and circumcisions. LFS use is expected to increase as commercial products will soon be available in the US. Recombinant sources and transgenic animal bioreactor systems will replace plasma-derived products and become the predominant sources for this product in the next decade. Other areas of innovation include the development of fibrin sealant bandages or dressings, expandable foams, and spray powders which will provide the haemophiliac the ability to rapidly attain control of traumatic haemorrhages prior to hospital treatment with a significant reduction in the use of i.v. clotting factors. Fibrin sealant products have the potential to provide life-saving control of haemorrhage, reduction in factor dependency, lower viral exposure risk, and medical care cost reduction.

  9. Dry-cured ham restructured with fibrin.

    PubMed

    Romero de Ávila, M D; Hoz, L; Ordóñez, J A; Cambero, M I

    2014-09-15

    The viability of a fibrinogen-thrombin system (FT) to bind fresh deboned hams for incorporation in the salting and ripening processes, to produce cured ham, was studied. The effects of the different processing variables (pH, NaCl concentration, temperature and gelation time) on FT, a meat emulsion mixed with FT, fresh pork portions and deboned hams restructured with FT were analyzed. The most stable and firmest fibrin gels were obtained after 6h of adding the FT, with less than 2% NaCl and pH 7-8.4. Scanning electron microscopy of the fibrin gel showed fibrillar structures with a high degree of cross-linking and a high density. Two structures were found in the binding area of restructured meat; one in the central part with similar characteristics to fibrin gels and, another in the area of contact between the meat surfaces, where a filamentous structure connected the fibrin gels with the muscle bundles. PMID:24767091

  10. Artificial lymphatic drainage systems for vascularized microfluidic scaffolds.

    PubMed

    Wong, Keith H K; Truslow, James G; Khankhel, Aimal H; Chan, Kelvin L S; Tien, Joe

    2013-08-01

    The formation of a stably perfused microvasculature continues to be a major challenge in tissue engineering. Previous work has suggested the importance of a sufficiently large transmural pressure in maintaining vascular stability and perfusion. Here we show that a system of empty channels that provides a drainage function analogous to that of lymphatic microvasculature in vivo can stabilize vascular adhesion and maintain perfusion rate in dense, hydraulically resistive fibrin scaffolds in vitro. In the absence of drainage, endothelial delamination increased as scaffold density increased from 6 to 30 mg/mL and scaffold hydraulic conductivity decreased by a factor of 20. Single drainage channels exerted only localized vascular stabilization, the extent of which depended on the distance between vessel and drainage as well as scaffold density. Computational modeling of these experiments yielded an estimate of 0.40-1.36 cm H2O for the minimum transmural pressure required for vascular stability. We further designed and constructed fibrin patches (0.8 × 0.9 cm(2)) that were perfused by a parallel array of vessels and drained by an orthogonal array of drainage channels; only with the drainage did the vessels display long-term stability and perfusion. This work underscores the importance of drainage in vascularization, especially when a dense, hydraulically resistive scaffold is used. PMID:23281125

  11. The GlueX Project at Jefferson Lab

    SciTech Connect

    Papandreou, Zisis

    2009-01-01

    One of the main scientific questions that remains unanswered in subatomic physics is the nature and behaviour of the "Glue" which holds the quarks together. The puzzling feature of this construction is that quarks are never found free, but only in triplets or pairs, a phenomenon known as "confinement". Since gluons carry colour charge, they can form chromoelectric flux tubes, which may result in unusual objects, such as glue-balls or hybrid combinations of gluons and quarks. In certain models, the later can be produced with quantum numbers not allowed in the simple quark picture. An international experiment (GlueX) at Jefferson Lab, Virginia, is being designed to search for such exotic hybrid mesons and thus elucidate the phenomenon of confinement. GlueX is considered a 'discovery' experiment; its salient features, the planned methodology of partial- wave analysis, and the R&D progress of its detector subsystems will be

  12. Applying Machine Learning to GlueX Data Analysis

    NASA Astrophysics Data System (ADS)

    Boettcher, Thomas

    2014-03-01

    GlueX is a high energy physics experiment with the goal of collecting data necessary for understanding confinement in quantum chromodynamics. Beginning in 2015, GlueX will collect huge amounts of data describing billions of particle collisions. In preparation for data collection, efforts are underway to develop a methodology for analyzing these large data sets. One of the primary challenges in GlueX data analysis is isolating events of interest from a proportionally large background. GlueX has recently begun approaching this selection problem using machine learning algorithms, specifically boosted decision trees. Preliminary studies indicate that these algorithms have the potential to offer vast improvements in both signal selection efficiency and purity over more traditional techniques.

  13. Scaffolded biology.

    PubMed

    Minelli, Alessandro

    2016-09-01

    Descriptions and interpretations of the natural world are dominated by dichotomies such as organism vs. environment, nature vs. nurture, genetic vs. epigenetic, but in the last couple of decades strong dissatisfaction with those partitions has been repeatedly voiced and a number of alternative perspectives have been suggested, from perspectives such as Dawkins' extended phenotype, Turner's extended organism, Oyama's Developmental Systems Theory and Odling-Smee's niche construction theory. Last in time is the description of biological phenomena in terms of hybrids between an organism (scaffolded system) and a living or non-living scaffold, forming unit systems to study processes such as reproduction and development. As scaffold, eventually, we can define any resource used by the biological system, especially in development and reproduction, without incorporating it as happens in the case of resources fueling metabolism. Addressing biological systems as functionally scaffolded systems may help pointing to functional relationships that can impart temporal marking to the developmental process and thus explain its irreversibility; revisiting the boundary between development and metabolism and also regeneration phenomena, by suggesting a conceptual framework within which to investigate phenomena of regular hypermorphic regeneration such as characteristic of deer antlers; fixing a periodization of development in terms of the times at which a scaffolding relationship begins or is terminated; and promoting plant galls to legitimate study objects of developmental biology. PMID:27287514

  14. Scaffolded biology.

    PubMed

    Minelli, Alessandro

    2016-09-01

    Descriptions and interpretations of the natural world are dominated by dichotomies such as organism vs. environment, nature vs. nurture, genetic vs. epigenetic, but in the last couple of decades strong dissatisfaction with those partitions has been repeatedly voiced and a number of alternative perspectives have been suggested, from perspectives such as Dawkins' extended phenotype, Turner's extended organism, Oyama's Developmental Systems Theory and Odling-Smee's niche construction theory. Last in time is the description of biological phenomena in terms of hybrids between an organism (scaffolded system) and a living or non-living scaffold, forming unit systems to study processes such as reproduction and development. As scaffold, eventually, we can define any resource used by the biological system, especially in development and reproduction, without incorporating it as happens in the case of resources fueling metabolism. Addressing biological systems as functionally scaffolded systems may help pointing to functional relationships that can impart temporal marking to the developmental process and thus explain its irreversibility; revisiting the boundary between development and metabolism and also regeneration phenomena, by suggesting a conceptual framework within which to investigate phenomena of regular hypermorphic regeneration such as characteristic of deer antlers; fixing a periodization of development in terms of the times at which a scaffolding relationship begins or is terminated; and promoting plant galls to legitimate study objects of developmental biology.

  15. The adhesive skin exudate of Notaden bennetti frogs (Anura: Limnodynastidae) has similarities to the prey capture glue of Euperipatoides sp. velvet worms (Onychophora: Peripatopsidae).

    PubMed

    Graham, Lloyd D; Glattauer, Veronica; Li, Dongmei; Tyler, Michael J; Ramshaw, John A M

    2013-08-01

    The dorsal adhesive secretion of the frog Notaden bennetti and the prey-capture "slime" ejected by Euperipatoides sp. velvet worms look and handle similarly. Both consist largely of protein (55-60% of dry weight), which provides the structural scaffold. The major protein of the onychophoran glue (Er_P1 for Euperipatoides rowelli) and the dominant frog glue protein (Nb-1R) are both very large (260-500 kDa), and both give oddly "turbulent" electrophoresis bands. Both major proteins, which are rich in Gly (16-17 mol%) and Pro (7-12 mol%) and contain 4-hydroxyproline (Hyp, 4 mol%), have the composition of intrinsically unstructured proteins. Their propensities for elastomeric or amyloid structures are discussed in light of Er_P1's large content of intrinsically disordered long tandem repeats. The low carbohydrate content of both glues is consistent with conventional protein glycosylation, which in the N. bennetti adhesive was explored by 2D PAGE. The N-linked sugars of Nb-1R appear to prevent inappropriate self-aggregation. Some peptide sequences from Nb-1R are presented. Overall, there are enough similarities between the frog and the velvet worm glues to suspect that they employ related mechanisms for setting and adhesion. A common paradigm is proposed for amphibian and onychophoran adhesives, which, if correct, points to convergent evolution. PMID:23665109

  16. The adhesive skin exudate of Notaden bennetti frogs (Anura: Limnodynastidae) has similarities to the prey capture glue of Euperipatoides sp. velvet worms (Onychophora: Peripatopsidae).

    PubMed

    Graham, Lloyd D; Glattauer, Veronica; Li, Dongmei; Tyler, Michael J; Ramshaw, John A M

    2013-08-01

    The dorsal adhesive secretion of the frog Notaden bennetti and the prey-capture "slime" ejected by Euperipatoides sp. velvet worms look and handle similarly. Both consist largely of protein (55-60% of dry weight), which provides the structural scaffold. The major protein of the onychophoran glue (Er_P1 for Euperipatoides rowelli) and the dominant frog glue protein (Nb-1R) are both very large (260-500 kDa), and both give oddly "turbulent" electrophoresis bands. Both major proteins, which are rich in Gly (16-17 mol%) and Pro (7-12 mol%) and contain 4-hydroxyproline (Hyp, 4 mol%), have the composition of intrinsically unstructured proteins. Their propensities for elastomeric or amyloid structures are discussed in light of Er_P1's large content of intrinsically disordered long tandem repeats. The low carbohydrate content of both glues is consistent with conventional protein glycosylation, which in the N. bennetti adhesive was explored by 2D PAGE. The N-linked sugars of Nb-1R appear to prevent inappropriate self-aggregation. Some peptide sequences from Nb-1R are presented. Overall, there are enough similarities between the frog and the velvet worm glues to suspect that they employ related mechanisms for setting and adhesion. A common paradigm is proposed for amphibian and onychophoran adhesives, which, if correct, points to convergent evolution.

  17. The GlueX Start Counter

    NASA Astrophysics Data System (ADS)

    Llodra, Anthony; Pooser, Eric; GlueX Collaboration

    2015-04-01

    The GlueX experiment, which is online as of October of 2014, will study meson photo production with unprecedented precision. This experiment will use the coherent bremsstrahlung technique to produce a 9 GeV linearly polarized photon beam incident on a liquid H2 target kept at a few degrees Kelvin. A Start Counter detector has been fabricated to identify the accelerator electron beam buckets, approximately 2 nanoseconds apart, and to provide accurate timing information. This detector is designed to operate at photon intensities of up to 108 γ/s in the coherent peak and provide a timing resolution of less than 350 picoseconds so as to provide successful identification of the electron beam buckets. It consists of a cylindrical array of 30 scintillators with pointed ends that bend towards the beam at the downstream end. The EJ-200 scintillator is best suited for the Start Counter due to its fast decay time on the order of 2 nanoseconds and long attenuation length. Silicon Photo Multiplier (SiPM) detectors have been selected as the readout system and are to be placed as close as possible, less than 300 micron, to the upstream end of each scintillator. The methods/details of the assembly and the optimization of the surface quality of scintillator paddles are discussed. This work was supported in part by DoE Contracts DE-FG02-99ER41065 and DE-AC05-06OR23177.

  18. Toward an understanding of fibrin branching structure

    NASA Astrophysics Data System (ADS)

    Fogelson, Aaron L.; Keener, James P.

    2010-05-01

    The blood clotting enzyme thrombin converts fibrinogen molecules into fibrin monomers which polymerize to form a fibrous three-dimensional gel. The concentration of thrombin affects the architecture of the resulting gel, in particular, a higher concentration of thrombin produces a gel with more branch points per unit volume and with shorter fiber segments between branch points. We propose a mechanism by which fibrin branching can occur and show that this mechanism can lead to dependence of the gel’s structure (at the time of gelation) on the rate at which monomer is supplied. A higher rate of monomer supply leads to a gel with a higher branch concentration and with shorter fiber segments between branch points. The origin of this dependence is explained.

  19. The crystallization of vaterite on fibrin

    NASA Astrophysics Data System (ADS)

    Kanakis, J.; Dalas, E.

    2000-10-01

    Fibrin, a protein endoproduct of blood coagulation was found to be a substrate favoring the deposition of vaterite crystals from stable supersaturated solutions at pH 8.5 and at 25°C. The apparent order for the vaterite crystallization reaction was found to be 1.0±0.1, suggesting a surface diffusion-controlled mechanism. The crystallization was studied by the constant solution composition technique thus making it possible for relatively large amounts of the overgrowth phase to be formed and identified exclusively as vaterite. Fibrin stabilizes this calcium carbonate polymorph, preventing the transformation to the thermodynamically more stable calcite. Analysis of the initial rates of the reaction as a function of the solution supersaturation, according to the classical nucleation theory, yielded a value of 21±1 mJ m -2 for the surface energy of the growing phase and a three-ion cluster forming the critical nucleus.

  20. Meniscal scaffolds.

    PubMed

    Myers, Kevin R; Sgaglione, Nicholas A; Goodwillie, Andrew D

    2014-12-01

    There are two scaffold products designed for meniscal reconstruction or substitution of partial meniscal defects that are currently available in the Europe: the collagen meniscal implant (CMI; Ivy Sports Medicine, Gräfelfing, Germany) and the polymer scaffold (PS; Actifit, Orteq Bioengineering, London, United Kingdom). The CMI has demonstrated improved clinical outcomes compared with baseline in patients with chronic postmeniscectomy symptoms with follow-up ranging from 5 to more than 10 years. There are also several comparative studies that report improved clinical scores in patients with chronic medial meniscus symptoms treated with CMI versus repeat partial meniscectomy, and a lower reoperation rate. Recently, PS insertion was shown to result in improved clinical outcomes in patients with chronic postmeniscectomy symptoms of the medial or lateral meniscus at short-term follow-up. However, there is currently no medium- or long-term data available for the PS. The use of meniscal scaffolds in the acute setting has not been found to result in improved outcomes in most studies. The authors' surgical indications for meniscal scaffold implantation, preferred surgical technique, and postoperative rehabilitation protocol are described. PMID:25172967

  1. Treatment of osteochondral defects in the rabbit's knee joint by implantation of allogeneic mesenchymal stem cells in fibrin clots.

    PubMed

    Berninger, Markus T; Wexel, Gabriele; Rummeny, Ernst J; Imhoff, Andreas B; Anton, Martina; Henning, Tobias D; Vogt, Stephan

    2013-01-01

    bone (11). The sandwich-technique combines bone grafting with current approaches in Tissue Engineering (5,6). This combination seems to be able to overcome the limitations seen in osteochondral grafts alone. After autologous bone grafting to the subchondral defect area, a membrane seeded with autologous chondrocytes is sutured above and facilitates to match the topology of the graft with the injured site. Of course, the previous bone reconstruction needs additional surgical time and often even an additional surgery. Moreover, to date, long-term data is missing (12). Tissue Engineering without additional bone grafting aims to restore the complex structure and properties of native articular cartilage by chondrogenic and osteogenic potential of the transplanted cells. However, again, it is usually only the cartilage tissue that is more or less regenerated. Additional osteochondral damage needs a specific further treatment. In order to achieve a regeneration of the multilayered structure of osteochondral defects, three-dimensional tissue engineered products seeded with autologous/allogeneic cells might provide a good regeneration capacity (11). Beside autologous chondrocytes, mesenchymal stem cells (MSC) seem to be an attractive alternative for the development of a full-thickness cartilage tissue. In numerous preclinical in vitro and in vivo studies, mesenchymal stem cells have displayed excellent tissue regeneration potential (13,14). The important advantage of mesenchymal stem cells especially for the treatment of osteochondral defects is that they have the capacity to differentiate in osteocytes as well as chondrocytes. Therefore, they potentially allow a multilayered regeneration of the defect. In recent years, several scaffolds with osteochondral regenerative potential have therefore been developed and evaluated with promising preliminary results (1,15-18). Furthermore, fibrin glue as a cell carrier became one of the preferred techniques in experimental cartilage

  2. The use of fibrin and gelatin fixation to repair a kinked internal carotid artery in carotid endarterectomy

    PubMed Central

    Kubota, Hisashi; Sanada, Yasuhiro; Tanikawa, Rokuya; Kato, Amami

    2016-01-01

    Background: The kinking of the internal carotid artery (ICA) after final closure in carotid endarterectomy (CEA) is thought to be uncommon. When it occurs, it is mandatory to reconstruct ICA to preserve normal blood flow. We herein present a case in which a fixation technique was applied to repair an ICA that became kinked during CEA. Case Description: A 68-year-old man presented with cerebral infarction due to an artery-to-artery embolism from the right cervical ICA stenosis. CEA was performed 12 days after admission. After final closure, a distal portion of ICA was found to have been kinked following plaque resection in CEA procedure. Fixation with fibrin glue and gelatin was used to reinforce the arterial wall and repair the kink. Postoperative magnetic resonance angiography demonstrated the release of the kink in ICA. Conclusion: Fixation with fibrin and gelatin is a salvage armamentarium that can be considered in CEA for the repair of kinked or tortuous ICA. PMID:27308092

  3. Constitution and in vivo test of micro-porous tubular scaffold for esophageal tissue engineering.

    PubMed

    Hou, Lei; Jin, Jiachang; Lv, Jingjing; Chen, Ling; Zhu, Yabin; Liu, Xingyu

    2015-11-01

    Current clinical techniques in treating long-gap esophageal defects often lead to complications and high morbidity. Aiming at long-gap synthetic esophageal substitute, we had synthesized a biodegradable copolymer, poly(L-lactide-co-caprolactone) (PLLC), with low glass transition temperature. In this work, we developed a tubular PLLC porous scaffold using a self-designed tubular mold and thermal induced phase separation (TIPS) method. In order to enhance the interaction between tissue and scaffold, fibrin, a natural fibrous protein derived from blood fibrinogen, was coated on the scaffold circumferential surface. The fibrin density was measured to be 1.23 ± 0.04 mg/cm(2). Primary epithelial cell culture demonstrated the improved in vitro biocompatibility. In animal study with partial scaffold implantation, in situ mucosa regeneration was observed along the degradation of the scaffold. These indicate that fibrin incorporated PLLC scaffold can greatly improve epithelial regeneration in esophagus repair, therefore serve as a good candidate for long-term evaluation of post-implantation at excision site.

  4. [Strategies to choose scaffold materials for tissue engineering].

    PubMed

    Gao, Qingdong; Zhu, Xulong; Xiang, Junxi; Lü, Yi; Li, Jianhui

    2016-02-01

    mixed with sustained-release nano-microsphere containing growth factors. What's more, the stent internal surface coated with glue/collagen matrix mixing layer containing bFGF and EGF so could supplying the early release of the two cytokines. Finally, combining the poly(L-lactic acid)/poly(ε-caprolactone) biliary stent with the induced cells was the last step for preparing tissue-engineered bile duct. This literature reviewed a variety of the existing tissue engineering scaffold materials and briefly introduced the impact factors on the characteristics of tissue engineering scaffold materials such as preparation procedure, surface modification of scaffold, and so on. We explored the choosing strategy of desired tissue engineering scaffold materials. PMID:27382767

  5. [Strategies to choose scaffold materials for tissue engineering].

    PubMed

    Gao, Qingdong; Zhu, Xulong; Xiang, Junxi; Lü, Yi; Li, Jianhui

    2016-02-01

    mixed with sustained-release nano-microsphere containing growth factors. What's more, the stent internal surface coated with glue/collagen matrix mixing layer containing bFGF and EGF so could supplying the early release of the two cytokines. Finally, combining the poly(L-lactic acid)/poly(ε-caprolactone) biliary stent with the induced cells was the last step for preparing tissue-engineered bile duct. This literature reviewed a variety of the existing tissue engineering scaffold materials and briefly introduced the impact factors on the characteristics of tissue engineering scaffold materials such as preparation procedure, surface modification of scaffold, and so on. We explored the choosing strategy of desired tissue engineering scaffold materials.

  6. Spider Glue Proteins Have Distinct Architectures Compared with Traditional Spidroin Family Members*

    PubMed Central

    Vasanthavada, Keshav; Hu, Xiaoyi; Tuton-Blasingame, Tiffany; Hsia, Yang; Sampath, Sujatha; Pacheco, Ryan; Freeark, Jordan; Falick, Arnold M.; Tang, Simon; Fong, Justine; Kohler, Kristin; La Mattina-Hawkins, Coby; Vierra, Craig

    2012-01-01

    Adhesive spider glues are required to perform a variety of tasks, including web construction, prey capture, and locomotion. To date, little is known regarding the molecular and structural features of spider glue proteins, in particular bioadhesives that interconnect dragline or scaffolding silks during three-dimensional web construction. Here we use biochemical and structural approaches to identify and characterize two aggregate gland specific gene products, AgSF1 and AgSF2, and demonstrate that these proteins co-localize to the connection joints of both webs and wrapping silks spun from the black widow spider, Latrodectus hesperus. Protein architectures are markedly divergent between AgSF1 and AgSF2, as well as traditional spider silk fibroin family members, suggesting connection joints consist of a complex proteinaceous network. AgSF2 represents a nonglycosylated 40-kDa protein that has novel internal amino acid block repeats with the consensus sequence NVNVN embedded in a glycine-rich matrix. Analysis of the amino acid sequence of AgSF1 reveals pentameric QPGSG iterations that are similar to conserved modular elements within mammalian elastin, a rubber-like elastomeric protein that interfaces with collagen. Wet-spinning methodology using purified recombinant proteins show AgSF1 has the potential to self-assemble into fibers. X-ray fiber diffraction studies performed on these synthetic fibers reveal the presence of noncrystalline domains that resemble classical rubber networks. Collectively, these data support that the aggregate gland serves to extrude a protein mixture that contains substances that allow for the self-assembly of fiber-like structures that interface with dragline silks to mediate prey capture. PMID:22927444

  7. Spider glue proteins have distinct architectures compared with traditional spidroin family members.

    PubMed

    Vasanthavada, Keshav; Hu, Xiaoyi; Tuton-Blasingame, Tiffany; Hsia, Yang; Sampath, Sujatha; Pacheco, Ryan; Freeark, Jordan; Falick, Arnold M; Tang, Simon; Fong, Justine; Kohler, Kristin; La Mattina-Hawkins, Coby; Vierra, Craig

    2012-10-19

    Adhesive spider glues are required to perform a variety of tasks, including web construction, prey capture, and locomotion. To date, little is known regarding the molecular and structural features of spider glue proteins, in particular bioadhesives that interconnect dragline or scaffolding silks during three-dimensional web construction. Here we use biochemical and structural approaches to identify and characterize two aggregate gland specific gene products, AgSF1 and AgSF2, and demonstrate that these proteins co-localize to the connection joints of both webs and wrapping silks spun from the black widow spider, Latrodectus hesperus. Protein architectures are markedly divergent between AgSF1 and AgSF2, as well as traditional spider silk fibroin family members, suggesting connection joints consist of a complex proteinaceous network. AgSF2 represents a nonglycosylated 40-kDa protein that has novel internal amino acid block repeats with the consensus sequence NVNVN embedded in a glycine-rich matrix. Analysis of the amino acid sequence of AgSF1 reveals pentameric QPGSG iterations that are similar to conserved modular elements within mammalian elastin, a rubber-like elastomeric protein that interfaces with collagen. Wet-spinning methodology using purified recombinant proteins show AgSF1 has the potential to self-assemble into fibers. X-ray fiber diffraction studies performed on these synthetic fibers reveal the presence of noncrystalline domains that resemble classical rubber networks. Collectively, these data support that the aggregate gland serves to extrude a protein mixture that contains substances that allow for the self-assembly of fiber-like structures that interface with dragline silks to mediate prey capture. PMID:22927444

  8. Aged venous thrombi: radioimmunoimaging with fibrin-specific monoclonal antibody

    SciTech Connect

    Rosebrough, S.F.; Grossman, Z.D.; McAfee, J.G.; Kudryk, B.J.; Subramanian, G.; Ritter-Hrncirik, C.A.; Witanowski, L.S.; Tillapaugh-Fay, G.; Urrutia, E.

    1987-02-01

    Radioimmunoimaging of fresh canine venous thrombi with a murine monoclonal antibody specific for human and dog fibrin has been reported. Successful imaging of canine deep venous thrombi 1, 3, and 5 days old at the time of antibody injection is reported. Images were positive in all dogs, and the uptake of fibrin-specific antibody was equivalent to that of fresh thrombi.

  9. Surgery for glue ear--a modern epidemic.

    PubMed

    Black, N

    1984-04-14

    Analysis of routine hospital statistics confirms anecdotal reports of an epidemic of surgery for glue ear. The surgical rate rose by 74% in Oxford Region between 1975 and 1981. The peak ages for surgery are 5-7 years, and the rates are higher in boys than in girls (1.4:1.00). The relative risk is high in social class I (1.16) and low in social class V (0.61). Although the prevalence of glue ear is hard to ascertain, the current surgical epidemic probably reflects an increase in apparent prevalence rather than a real increase in morbidity.

  10. Activated Schwann Cell-Like Cells on Aligned Fibrin-Poly(Lactic-Co-Glycolic Acid) Structures: A Novel Construct for Application in Peripheral Nerve Regeneration.

    PubMed

    Schuh, Christina M A P; Morton, Tatjana J; Banerjee, Asmita; Grasl, Christian; Schima, Heinrich; Schmidhammer, Robert; Redl, Heinz; Ruenzler, Dominik

    2015-01-01

    Tissue engineering approaches in nerve regeneration search for ways to support gold standard therapy (autologous nerve grafts) and to improve results by bridging nerve defects with different kinds of conduits. In this study, we describe electrospinning of aligned fibrin-poly(lactic-co-glycolic acid) (PLGA) fibers in an attempt to create a biomimicking tissue-like material seeded with Schwann cell-like cells (SCLs) in vitro for potential use as an in vivo scaffold. Rat adipose-derived stem cells (rASCs) were differentiated into SCLs and evaluated with flow cytometry concerning their differentiation and activation status [S100b, P75, myelin-associated glycoprotein (MAG), and protein 0 (P0)]. After receiving the proliferation stimulus forskolin, SCLs expressed S100b and P75; comparable to native, activated Schwann cells, while cultured without forskolin, cells switched to a promyelinating phenotype and expressed S100b, MAG, and P0. Human fibrinogen and thrombin, blended with PLGA, were electrospun and the alignment and homogeneity of the fibers were proven by scanning electron microscopy. Electrospun scaffolds were seeded with SCLs and the formation of Büngner-like structures in SCLs was evaluated with phalloidin/propidium iodide staining. Carrier fibrin gels containing rASCs acted as a self-shaping matrix to form a tubular structure. In this study, we could show that rASCs can be differentiated into activated, proliferating SCLs and that these cells react to minimal changes in stimulus, switching to a promyelinating phenotype. Aligned electrospun fibrin-PLGA fibers promoted the formation of Büngner-like structures in SCLs, which also rolled the fibrin-PLGA matrix into a tubular scaffold. These in vitro findings favor further in vivo testing. PMID:26372904

  11. Fibrin formation by staphylothrombin facilitates Staphylococcus aureus-induced platelet aggregation.

    PubMed

    Vanassche, Thomas; Kauskot, Alexandre; Verhaegen, Jan; Peetermans, Willy E; van Ryn, Joanne; Schneewind, Olaf; Hoylaerts, Marc F; Verhamme, Peter

    2012-06-01

    Interactions of Staphylococcus aureus (S. aureus) and platelets play an important role in the pathogenesis of intravascular infections such as infective endocarditis (IE). A typical feature of S. aureus is the ability to generate thrombin activity through the secretion of two prothrombin activating molecules, staphylocoagulase and von Willebrand factor-binding protein (vWbp), which bind to human prothrombin to form the enzymatically active staphylothrombin complex. The role of staphylothrombin in the interaction between S. aureus and platelets has not yet been studied. We found that in contrast with thrombin, staphylothrombin did not directly activate human platelets. However, the staphylothrombin-mediated conversion of fibrinogen to fibrin initiated platelet aggregation and secondary activation and facilitated S. aureus-platelet interactions. Both the genetic absence of staphylocoagulase and vWbp and pharmacological inhibition of staphylothrombin increased the lag time to aggregation, and reduced platelet trapping by S. aureus in high shear stress conditions. The combined inhibition of staphylothrombin and immunoglobulin binding to platelets completely abolished the ability of S. aureus to aggregate platelets in vitro. In conclusion, although staphylothrombin did not directly activate platelets, the formation of a fibrin scaffold facilitated bacteria-platelet interaction, and the inhibition of staphylothrombin resulted in a reduced activation of platelets by S. aureus. PMID:22437005

  12. Tissue-Engineered Fibrin-Based Heart Valve with Bio-Inspired Textile Reinforcement.

    PubMed

    Moreira, Ricardo; Neusser, Christine; Kruse, Magnus; Mulderrig, Shane; Wolf, Frederic; Spillner, Jan; Schmitz-Rode, Thomas; Jockenhoevel, Stefan; Mela, Petra

    2016-08-01

    The mechanical properties of tissue-engineered heart valves still need to be improved to enable their implantation in the systemic circulation. The aim of this study is to develop a tissue-engineered valve for the aortic position - the BioTexValve - by exploiting a bio-inspired composite textile scaffold to confer native-like mechanical strength and anisotropy to the leaflets. This is achieved by multifilament fibers arranged similarly to the collagen bundles in the native aortic leaflet, fixed by a thin electrospun layer directly deposited on the pattern. The textile-based leaflets are positioned into a 3D mould where the components to form a fibrin gel containing human vascular smooth muscle cells are introduced. Upon fibrin polymerization, a complete valve is obtained. After 21 d of maturation by static and dynamic stimulation in a custom-made bioreactor, the valve shows excellent functionality under aortic pressure and flow conditions, as demonstrated by hydrodynamic tests performed according to ISO standards in a mock circulation system. The leaflets possess remarkable burst strength (1086 mmHg) while remaining pliable; pronounced extracellular matrix production is revealed by immunohistochemistry and biochemical assay. This study demonstrates the potential of bio-inspired textile-reinforcement for the fabrication of functional tissue-engineered heart valves for the aortic position. PMID:27377438

  13. The Fibrin Matrix Regulates Angiogenic Responses within the Hemostatic Microenvironment through Biochemical Control

    PubMed Central

    Hadjipanayi, Ektoras; Kuhn, Peer-Hendrik; Kuekrek, Haydar; Mirzoyan, Lilit; Hummel, Anja; Kirchhoff, Katharina; Salgin, Burak; Isenburg, Sarah; Dornseifer, Ulf; Ninkovic, Milomir; Machens, Hans-Günther; Schilling, Arndt F.

    2015-01-01

    Conceptually, premature initiation of post-wound angiogenesis could interfere with hemostasis, as it relies on fibrinolysis. The mechanisms facilitating orchestration of these events remain poorly understood, however, likely due to limitations in discerning the individual contribution of cells and extracellular matrix. Here, we designed an in vitro Hemostatic-Components-Model (HCM) to investigate the role of the fibrin matrix as protein factor-carrier, independent of its cell-scaffold function. After characterizing the proteomic profile of HCM-harvested matrix releasates, we demonstrate that the key pro-/anti-angiogenic factors, VEGF and PF4, are differentially bound by the matrix. Changing matrix fibrin mass consequently alters the balance of releasate factor concentrations, with differential effects on basic endothelial cell (EC) behaviors. While increasing mass, and releasate VEGF levels, promoted EC chemotactic migration, it progressively inhibited tube formation, a response that was dependent on PF4. These results indicate that the clot’s matrix component initially serves as biochemical anti-angiogenic barrier, suggesting that post-hemostatic angiogenesis follows fibrinolysis-mediated angiogenic disinhibition. Beyond their significance towards understanding the spatiotemporal regulation of wound healing, our findings could inform the study of other pathophysiological processes in which coagulation and angiogenesis are prominent features, such as cardiovascular and malignant disease. PMID:26317771

  14. A comparison of the mechanical, kinetic, and biochemical properties of fibrin clots formed with two different fibrin sealants.

    PubMed

    Hickerson, William L; Nur, Israel; Meidler, Roberto

    2011-01-01

    The objective of the present study was to compare the mechanical, kinetic, and biochemical properties of fibrin clots produced using EVICEL Fibrin Sealant (Human) and TISSEEL Fibrin Sealant. The stiffness/elasticity and strength of fibrin clots formed with EVICEL and TISSEEL were assessed using applied mechanical force and thromboelastography (TEG). The factor XIII content of the fibrin clots was also evaluated. Mean Young modulus and tensile strength of the fibrin clots produced by EVICEL were significantly higher than those of clots produced by TISSEEL (P < 0.05 for both). The mean time to initial clot formation and mean time to the predefined level of clot formation were numerically shorter for EVICEL compared with TISSEEL. Furthermore, mean maximal amplitude of the clots formed with EVICEL was significantly greater than that for the clots formed with TISSEEL. Mean concentration of factor XIII for the EVICEL fibrinogen samples tested was 9 IU/ml compared with undetectable concentrations of factor XIII for the TISSEEL fibrinogen samples. Fibrin clots formed with EVICEL have a much higher resistance to stretching and tensile strength and are more capable of maintaining their structure against applied force than those formed with TISSEEL. EVICEL also allows more rapid development of fibrin clots than TISSEEL. This superior clot strength and resilience obtained with EVICEL relative to TISSEEL may be due in large part to the presence of factor XIII.

  15. Concentration of Fibrin and Presence of Plasminogen Affect Proliferation, Fibrinolytic Activity, and Morphology of Human Fibroblasts and Keratinocytes in 3D Fibrin Constructs

    PubMed Central

    Reinertsen, Erik; Skinner, Michael; Wu, Benjamin

    2014-01-01

    Fibrin is a hemostatic protein found in the clotting cascade. It is used in the operating room to stop bleeding and deliver cells and growth factors to heal wounds. However, formulations of clinically approved fibrin are optimized for hemostasis, and the extent to which biochemical and physical cues in fibrin mediate skin cell behavior is not fully understood nor utilized in the design of biomaterials. To determine if the concentration of fibrinogen and the presence of plasminogen affect cell behavior relevant to wound healing, we fabricated three-dimensional fibrin constructs made from 5, 10, or 20 mg/mL of clinical fibrin or plasminogen-depleted (PD) fibrin. We cultured dermal fibroblasts or epidermal keratinocytes in these constructs. Fibroblasts proliferated similarly in both types of fibrin, but keratinocytes proliferated more in low concentrations of clinical fibrin and less in PD fibrin. Clinical fibrin constructs with fibroblasts were less stiff and degraded faster than PD fibrin constructs with fibroblasts. Similarly, keratinocytes degraded clinical fibrin, but not PD fibrin. Fibroblast spreading varied with fibrin concentration in both types of fibrin. In conclusion, the concentration of fibrinogen and the presence of plasminogen affect fibroblast and keratinocyte proliferation, morphology, and fibrin degradation. Creating materials with heterogeneous regions of fibrin formulations and concentrations could be a novel strategy for controlling the phenotype of encapsulated fibroblasts and keratinocytes, and the subsequent biomechanical properties of the construct. However, other well-investigated aspects of wound healing remain to be utilized in the design of fibrin biomaterials, such as autocrine and paracrine signaling between fibroblasts, keratinocytes, and immune cells. PMID:24738616

  16. Kinetics of ligation of fibrin oligomers.

    PubMed

    Nelb, G W; Kamykowski, G W; Ferry, J D

    1980-07-10

    Human fibrinogen was treated with thrombin in the presence of fibrinoligase and calcium ion at pH 8.5, ionic strength 0.45, and the ensuring polymerization was interrupted at various time intervals (t) both before and after the clotting time (tc) by solubilization with a solution of sodium dodecyl sulfate and urea. Aliquots of the solubilized protein were subjected to gel electrophoresis on polyacrylamide gels after disulfide reduction by dithiothreitol and on agarose gels without reduction. The degree of gamma-gamma ligation was determined from the former and the size distribution of ligated oligomers, for degree of polymerization x from 1 to 10, from the latter. The degree of gamma-gamma ligation was calculated independently from the size distribution with the assumption that every junction between two fibrin monomers remaining intact after solubilization is ligated, and this agreed well with the direct determination. The size distribution at t/tc = 1.3 to 1.6 differed somewhat from that calculated by the classical theory of linear polycondensation on the assumption that all reactive sites react with equal probability and rate. Analysis of the difference suggests that ligation of a fibrin digomer is not a random process; the probability of ligation of a given junction between two monomers increases with the oligomer length. The number-average degree of polymerization, xn, of ligated oligomers increases approximately linearly with time up to a value of 1.6. PMID:7391026

  17. Measurement of Fibrin Fiber Strength using AFM

    NASA Astrophysics Data System (ADS)

    Jawerth, Louise; Falvo, Mchael; Canning, Anthony; Matthews, Garrett; Superfine, Richard; Guthold, Martin

    2003-11-01

    Blood clots usually form in the event of injury or damage to blood vessels to prevent the loss of blood. Moreover, as we age, blood clots often form in undesired locations, i.e. in blood vessels around the heart or brain, or in uninjured vessels resulting in heart attacks or strokes. Fibrin fibers, the skeleton of a blood clot, essentially perform the mechanical task of creating a blockage that stems blood flow. Thus, a better understanding of the mechanical properties of these fibers, such as the tensile strength and Young's modulus, will enhance our understanding of blood clots. For quantitative stress and strain measurements, we need to image the deformation of the fiber and measure the applied force simultaneously. For this reason, we are combining fluorescent microscopy with atomic force microscopy. Fibrin fibers were fluorescently labeled with streptavidin-coated quantum dots and deposited on a functionalized glass substrate, imaged and manipulated under buffer. We will describe our progress in obtaining quantitative lateral force measurements under buffer simultaneous with strain measurements from optical microscope images.

  18. Control of DNA hybridization by photoswitchable molecular glue.

    PubMed

    Dohno, Chikara; Nakatani, Kazuhiko

    2011-12-01

    Hybridization of DNA is one of the most intriguing events in molecular recognition and is essential for living matter to inherit life beyond generations. In addition to the function of DNA as genetic material, DNA hybridization is a key to control the function of DNA-based materials in nanoscience. Since the hybridization of two single stranded DNAs is a thermodynamically favorable process, dissociation of the once formed DNA duplex is normally unattainable under isothermal conditions. As the progress of DNA-based nanoscience, methodology to control the DNA hybridization process has become increasingly important. Besides many reports using the chemically modified DNA for the regulation of hybridization, we focused our attention on the use of a small ligand as the molecular glue for the DNA. In 2001, we reported the first designed molecule that strongly and specifically bound to the mismatched base pairs in double stranded DNA. Further studies on the mismatch binding molecules provided us a key discovery of a novel mode of the binding of a mismatch binding ligand that induced the base flipping. With these findings we proposed the concept of molecular glue for DNA for the unidirectional control of DNA hybridization and, eventually photoswitchable molecular glue for DNA, which enabled the bidirectional control of hybridization under photoirradiation. In this tutorial review, we describe in detail how we integrated the mismatch binding ligand into photoswitchable molecular glue for DNA, and the application and perspective in DNA-based nanoscience.

  19. Gravity: The Glue of the Universe. History and Activities.

    ERIC Educational Resources Information Center

    Gilbert, Harry; Smith, Diana Gilbert

    This book presents a story of the history of gravity, the glue of the universe, and is based on two premises: (1) an understanding of mathematics is not required to grasp the concepts and implications of relativity; and (2) relativity has altered forever the perceptions of gravity, space, time, and how the universe works. A narrative text section…

  20. Single-molecule force spectroscopy studies of fibrin 'A-a' polymerization interactions via the atomic force microscope

    NASA Astrophysics Data System (ADS)

    Averett, Laurel E.

    Fibrin, the polymerized form of the soluble plasma protein fibrinogen, plays a critical role in hemostasis as the structural scaffold of blood clots. The primary functions of fibrin are to withstand the shear forces of blood flow and provide mechanical stability to the clot, protecting the wound. While studies have investigated the mechanical properties of fibrin constructs, the response to force of critical polymerization interactions such as the 'A--a' knob--hole interaction remains unclear. Herein, the response of the 'A--a' bond to force was examined at the single-molecule level using the atomic force microscope. Force spectroscopy methodology was developed to examine the 'A--a' interaction while reducing the incidence of both nonspecific and multiple molecule interactions. The rupture of this interaction resulted in a previously unreported characteristic force profile comprised of up to four events. We hypothesized that the first event represented reorientation of the fibrinogen molecule, the second and third represented unfolding of structures in the D region of fibrinogen, and the last event was the rupture of the 'A--a' bond weakened by prior structural unfolding. The configuration, molecular extension, and kinetic parameters of each event in the characteristic pattern were examined to compare the unfolding of fibrin to other proteins unfolded by force. Fitting the pattern with polymer models showed that the D region of fibrinogen could lengthen by ˜50% of the length of a fibrin monomer before rupture of the 'A--a' bond. Analysis showed that the second and third events had kinetic parameters similar to other protein structures unfolded by force. Studies of the dependence of the characteristic pattern on calcium, concentration of sodium chloride, pH, and temperature demonstrated that the incidence of the last event was affected by solution conditions. However, only low pH and high temperatures reduced the probability that an interaction was characteristic

  1. Osteogenic potential of human umbilical cord-derived mesenchymal stromal cells cultured with umbilical cord blood-derived fibrin: a preliminary study.

    PubMed

    Baba, Kyoko; Yamazaki, Yasuharu; Ishiguro, Masashi; Kumazawa, Kenichi; Aoyagi, Kazuya; Ikemoto, Shigehiro; Takeda, Akira; Uchinuma, Eiju

    2013-12-01

    This study examined the potential for osteogenesis via regenerative medicine using autologous tissues (umbilical cord (UC) and umbilical cord blood (UCB)) in nude mice. The study was designed to provide the three elements required for regenerative medicine (cell, scaffold, and growth factor) and autoserum for culture by means of autologous tissues. Mesenchymal stromal cells were obtained from UC (UC-MSCs). Fibrin, platelet-rich-plasma, and autoserum were obtained from UCB as scaffold, growth factor and serum for culture respectively. UC-MSCs were obtained from Wharton jelly and cultured with UCB-derived fibrin (UCB-fibrin) for 3-4 weeks to induce their differentiation into osteoblasts. They were implanted subcutaneously into the dorsum of male nude mice for 6 weeks prior to undergoing assessment. The assessments performed were haematoxylin and eosin, and alizarin red staining, immunohistochemical staining of human mitochondria, scanning electron microscopy, scanning electron microscopy with energy dispersive X-ray spectrometry and real-time reverse transcriptase-polymerase chain reaction to assess the expressions of osteoblast markers. Consequently, the differentiation of UC-MSCs into osteoblasts and the production of hydroxyapatite were verified. This study suggested the possible formation of bone tissue using biomedical materials obtained from UC and UCB.

  2. Three Dimensional Collagen Scaffold Promotes Intrinsic Vascularisation for Tissue Engineering Applications

    PubMed Central

    Chan, Elsa C.; Kuo, Shyh-Ming; Kong, Anne M.; Morrison, Wayne A.; Dusting, Gregory J.; Mitchell, Geraldine M.

    2016-01-01

    Here, we describe a porous 3-dimensional collagen scaffold material that supports capillary formation in vitro, and promotes vascularization when implanted in vivo. Collagen scaffolds were synthesized from type I bovine collagen and have a uniform pore size of 80 μm. In vitro, scaffolds seeded with primary human microvascular endothelial cells suspended in human fibrin gel formed CD31 positive capillary-like structures with clear lumens. In vivo, after subcutaneous implantation in mice, cell-free collagen scaffolds were vascularized by host neovessels, whilst a gradual degradation of the scaffold material occurred over 8 weeks. Collagen scaffolds, impregnated with human fibrinogen gel, were implanted subcutaneously inside a chamber enclosing the femoral vessels in rats. Angiogenic sprouts from the femoral vessels invaded throughout the scaffolds and these degraded completely after 4 weeks. Vascular volume of the resulting constructs was greater than the vascular volume of constructs from chambers implanted with fibrinogen gel alone (42.7±5.0 μL in collagen scaffold vs 22.5±2.3 μL in fibrinogen gel alone; p<0.05, n = 7). In the same model, collagen scaffolds seeded with human adipose-derived stem cells (ASCs) produced greater increases in vascular volume than did cell-free collagen scaffolds (42.9±4.0 μL in collagen scaffold with human ASCs vs 25.7±1.9 μL in collagen scaffold alone; p<0.05, n = 4). In summary, these collagen scaffolds are biocompatible and could be used to grow more robust vascularized tissue engineering grafts with improved the survival of implanted cells. Such scaffolds could also be used as an assay model for studies on angiogenesis, 3-dimensional cell culture, and delivery of growth factors and cells in vivo. PMID:26900837

  3. Three Dimensional Collagen Scaffold Promotes Intrinsic Vascularisation for Tissue Engineering Applications.

    PubMed

    Chan, Elsa C; Kuo, Shyh-Ming; Kong, Anne M; Morrison, Wayne A; Dusting, Gregory J; Mitchell, Geraldine M; Lim, Shiang Y; Liu, Guei-Sheung

    2016-01-01

    Here, we describe a porous 3-dimensional collagen scaffold material that supports capillary formation in vitro, and promotes vascularization when implanted in vivo. Collagen scaffolds were synthesized from type I bovine collagen and have a uniform pore size of 80 μm. In vitro, scaffolds seeded with primary human microvascular endothelial cells suspended in human fibrin gel formed CD31 positive capillary-like structures with clear lumens. In vivo, after subcutaneous implantation in mice, cell-free collagen scaffolds were vascularized by host neovessels, whilst a gradual degradation of the scaffold material occurred over 8 weeks. Collagen scaffolds, impregnated with human fibrinogen gel, were implanted subcutaneously inside a chamber enclosing the femoral vessels in rats. Angiogenic sprouts from the femoral vessels invaded throughout the scaffolds and these degraded completely after 4 weeks. Vascular volume of the resulting constructs was greater than the vascular volume of constructs from chambers implanted with fibrinogen gel alone (42.7±5.0 μL in collagen scaffold vs 22.5±2.3 μL in fibrinogen gel alone; p<0.05, n = 7). In the same model, collagen scaffolds seeded with human adipose-derived stem cells (ASCs) produced greater increases in vascular volume than did cell-free collagen scaffolds (42.9±4.0 μL in collagen scaffold with human ASCs vs 25.7±1.9 μL in collagen scaffold alone; p<0.05, n = 4). In summary, these collagen scaffolds are biocompatible and could be used to grow more robust vascularized tissue engineering grafts with improved the survival of implanted cells. Such scaffolds could also be used as an assay model for studies on angiogenesis, 3-dimensional cell culture, and delivery of growth factors and cells in vivo.

  4. Interactions between ultrasound stimulated microbubbles and fibrin clots

    NASA Astrophysics Data System (ADS)

    Acconcia, Christopher; Leung, Ben Y. C.; Hynynen, Kullervo; Goertz, David E.

    2013-07-01

    While it is well established that ultrasound stimulated microbubbles (USMBs) can potentiate blood clot lysis, the mechanisms are not well understood. Here we examine the interaction between USMBs and fibrin clots, which are comprised of fibrin networks that maintain the mechanical integrity of blood clots. High speed camera observations demonstrated that USMBs can penetrate fibrin clots. Two-photon microscopy revealed that penetrating bubbles can leave behind patent "tunnels" along their paths and that fluid can be transported into the clots. Finally, it is observed that primary radiation forces associated with USMBs can induce local deformation and macroscopic translation of clot boundaries.

  5. Tumour imaging by the detection of fibrin clots in tumour stroma using an anti-fibrin Fab fragment.

    PubMed

    Obonai, Toshifumi; Fuchigami, Hirobumi; Furuya, Fumiaki; Kozuka, Naoyuki; Yasunaga, Masahiro; Matsumura, Yasuhiro

    2016-01-01

    The diagnosis of early and aggressive types of cancer is important for providing effective cancer therapy. Cancer-induced fibrin clots exist only within lesions. Previously, we developed a monoclonal antibody (clone 102-10) that recognizes insoluble fibrin but not fibrinogen or soluble fibrin and confirmed that fibrin clots form continuously in various cancers. Here, we describe the development of a Fab fragment probe of clone 102-10 for tumour imaging. The distribution of 102-10 Fab was investigated in genetically engineered mice bearing pancreatic ductal adenocarcinoma (PDAC), and its effect on blood coagulation was examined. Immunohistochemical and ex vivo imaging revealed that 102-10 Fab was distributed selectively in fibrin clots in PDAC tumours 3 h after injection and that it disappeared from the body after 24 h. 102-10 Fab had no influence on blood coagulation or fibrinolysis. Tumour imaging using anti-fibrin Fab may provide a safe and effective method for the diagnosis of invasive cancers by detecting fibrin clots in tumour stroma.

  6. Spatiotemporal Characterization of a Fibrin Clot Using Quantitative Phase Imaging

    PubMed Central

    Gannavarpu, Rajshekhar; Bhaduri, Basanta; Tangella, Krishnarao; Popescu, Gabriel

    2014-01-01

    Studying the dynamics of fibrin clot formation and its morphology is an important problem in biology and has significant impact for several scientific and clinical applications. We present a label-free technique based on quantitative phase imaging to address this problem. Using quantitative phase information, we characterized fibrin polymerization in real-time and present a mathematical model describing the transition from liquid to gel state. By exploiting the inherent optical sectioning capability of our instrument, we measured the three-dimensional structure of the fibrin clot. From this data, we evaluated the fractal nature of the fibrin network and extracted the fractal dimension. Our non-invasive and speckle-free approach analyzes the clotting process without the need for external contrast agents. PMID:25386701

  7. A Novel Technique for Conjunctivoplasty in a Rabbit Model: Platelet-Rich Fibrin Membrane Grafting

    PubMed Central

    Çakmak, Hasan Basri; Dereli Can, Gamze; Ünverdi, Hatice; Toklu, Yasin; Hücemenoğlu, Sema

    2016-01-01

    Purpose. To investigate the effect of platelet-rich fibrin (PRF) membrane on wound healing. Methods. Twenty-four right eyes of 24 New Zealand rabbits equally divided into 2 groups for the study design. After the creation of 5 × 5 mm conjunctival damage, it was secured with PRF membrane, which was generated from the rabbit's whole blood samples in PRF membrane group, whereas damage was left unsutured in the control group. Three animals were sacrificed in each group on the 1st, 3rd, 7th, and 28th postoperative days. Immunohistochemical (IHC) stainings and biomicroscopic evaluation were performed and compared between groups. Results. PRF membrane generated significant expressions of vascular endothelial growth factor (VEGF), transforming growth factor-beta (TGF-β), and platelet-derived growth factor (PDGF) in the early postoperative period. However, the IHC evaluation allowed showing the excessive staining at day 28, in control group. Biomicroscopic evaluation revealed complete epithelialization in PRF membrane group, but none of the cases showed complete healing in the control group. Conclusions. This experimental study showed us the beneficial effects of the PRF membrane on conjunctival healing. Besides its chemical effects, it provides mechanical support as a scaffold for the migrating cells that are important for ocular surface regeneration. These overall results encourage us to apply autologous PRF membrane as a growth factor-enriched endogenous scaffold for ocular surface reconstruction. PMID:27747098

  8. Glue, steam and Clarivein--Best practice techniques and evidence.

    PubMed

    Whiteley, Mark S

    2015-11-01

    In July 2013, the National Institute of Health and Clinical Excellence (NICE) recommended "endothermal" ablation (meaning endovenous thermal ablation) is the first line treatment for truncal venous reflux in varicose veins. The initial endovenous thermoablation devices were radiofrequency ablation and endovenous laser ablation. More recently, Glue (cyanoacrylate), endovenous steam and Clarivein (mechanochemical ablation or MOCA) have entered the market as new endovenous techniques for the treatment of varicose veins. Glue and Clarivein do not require tumescent anaesthesia and do not use heat and therefore termed non-tumescent non-thermal (NTNT). Steam both requires tumescence and is also a thermal technique (TT). This article reviews the current position of these 3 new technologies in the treatment of varicose veins.

  9. Search for Gluonic Excitations in Hadrons with GlueX

    SciTech Connect

    Igor Senderovich

    2011-12-01

    The GlueX experiment will employ a linearly polarized 9 GeV tagged photon beam incident on a liquid hydrogen target to search for exotic states in the light meson spectrum. Optimized for this purpose, the detector has a highly uniform acceptance over nearly 4p solid angle, with high efficiency for both neutral and charged final state particles. An overview of the physics motivation and detector design will be given.

  10. Fibrin Sealants in Dura Sealing: A Systematic Literature Review

    PubMed Central

    2016-01-01

    Background Fibrin sealants are widely used in neurosurgery to seal the suture line, provide watertight closure, and prevent cerebrospinal fluid leaks. The aim of this systematic review is to summarize the current efficacy and safety literature of fibrin sealants in dura sealing and the prevention/treatment of cerebrospinal fluid leaks. Methods A comprehensive electronic literature search was run in the following databases: Cochrane Database of Systematic Reviews, Cochrane Central Resister of Controlled Trials, clinicaltrials.gov, MEDLINE/PubMed, and EMBASE. Titles and abstracts of potential articles of interest were reviewed independently by 3 of the authors. Results A total of 1006 database records and additional records were identified. After screening for duplicates and relevance, a total of 78 articles were assessed by the investigators for eligibility. Thirty-eight were excluded and the full-text of 40 articles were included in the qualitative synthesis. Seven of these included only safety data and were included in the safety assessment. The remaining 33 articles included findings from 32 studies that enrolled a total of 2935 patients who were exposed to fibrin sealant. Among these 33 studies there were only 3 randomized controlled trials, with the remaining being prospective cohort analysis, case controlled studies, prospective or retrospective case series. One randomized controlled trial, with 89 patients exposed to fibrin sealant, found a greater rate of intraoperative watertight dura closure in the fibrin sealant group than the control group (92.1% versus 38.0%, p<0.001); however, post-operative cerebrospinal fluid leakage occurred in more fibrin sealant than control patients (6.7% versus 2.0%, p>0.05). Other clinical trials evaluated the effect of fibrin sealant in the postoperative prevention of cerebrospinal fluid leaks. These were generally lower level evidence studies (ie, not prospective, randomized, controlled trials) that were not designed or

  11. Profile of solvent abusers (glue sniffers) in East Malaysia.

    PubMed

    Zabedah, M Y; Razak, M; Zakiah, I; Zuraidah, A B

    2001-12-01

    Solvent abuse is deliberate sniffing of an organic solvent for the intention of altering the physiological state of the individual. It is also commonly known as glue sniffing because glue is the most commonly abused substance. This form of substance abuse is widespread throughout the world and usually popular among secondary school children and young adults because of its easy availability and it is cheaper compared with most drugs of abuse. In Malaysia this problem has been recognized especially among the children in East Malaysia. In this study, 37 children and young adults from or around Kota Kinabalu, Sabah were referred to Bukit Padang Psychiatric Hospital by the Anti-drug Task force for suspected solvent abuse. These children were interviewed using questionaire and examined physically. Blood and urine were analysed for toluene and hippuric acid. 27 of the children, age ranging between 8 and 20 years, willingly admitted to sniffing glue for a period between a few months to 2 years. Most of them were children of Fillipino illegal immigrants in Kota Kinabalu. Biochemical parameters were found to be normal. Two of them were pale with low hemoglobin and 7 had eosinophilia. Haematuria and proteinuria were found in 21 children (78%). 16 blood samples with toluene levels ranging from 0.3 to 41 microg/ml and 10 urine samples have elevated urinary hippuric acid levels ranging from 1.2 to 7.4 mg/ml. Strong positive correlation was noted between mean blood toluene levels and duration of abuse. PMID:12166590

  12. Glue septal ablation: A promising alternative to alcohol septal ablation

    PubMed Central

    Aytemir, Kudret; Oto, Ali

    2016-01-01

    Hypertrophic cardiomyopathy (HCM) is defined as myocardial hypertrophy in the absence of another cardiac or systemic disease capable of producing the magnitude of present hypertrophy. In about 70% of patients with HCM, there is left ventricular outflow tract (LVOT) obstruction (LVOTO) and this is known as obstructive type of hypertrophic cardiomyopathy (HOCM). Cases refractory to medical treatment have had two options either surgical septal myectomy or alcohol septal ablation (ASA) to alleviate LVOT gradient. ASA may cause some life-threatening complications including conduction disturbances and complete heart block, hemodynamic compromise, ventricular arrhythmias, distant and massive myocardial necrosis. Glue septal ablation (GSA) is a promising technique for the treatment of HOCM. Glue seems to be superior to alcohol due to some intrinsic advantageous properties of glue such as immediate polymerization which prevents the leak into the left anterior descending coronary artery and it is particularly useful in patients with collaterals to the right coronary artery in whom alcohol ablation is contraindicated. In our experience, GSA is effective and also a safe technique without significant complications. GSA decreases LVOT gradient immediately after the procedure and this reduction persists during 12 months of follow-up. It improves New York Heart Association functional capacity and decrease interventricular septal wall thickness. Further studies are needed in order to assess the long-term efficacy and safety of this technique. PMID:27011786

  13. In situ vascularization of injectable fibrin/poly(ethylene glycol) hydrogels by human amniotic fluid-derived stem cells.

    PubMed

    Benavides, Omar M; Brooks, Abigail R; Cho, Sung Kyung; Petsche Connell, Jennifer; Ruano, Rodrigo; Jacot, Jeffrey G

    2015-08-01

    One of the greatest challenges in regenerative medicine is generating clinically relevant engineered tissues with functional blood vessels. Vascularization is a key hurdle faced in designing tissue constructs larger than the in vivo limit of oxygen diffusion. In this study, we utilized fibrin-based hydrogels to serve as a foundation for vascular formation, poly(ethylene glycol) (PEG) to modify fibrinogen and increase scaffold longevity, and human amniotic fluid-derived stem cells (AFSC) as a source of vascular cell types (AFSC-EC). AFSC hold great potential for use in regenerative medicine strategies, especially those involving autologous congenital applications, and we have shown previously that AFSC-seeded fibrin-PEG hydrogels have the potential to form three-dimensional vascular-like networks in vitro. We hypothesized that subcutaneously injecting these hydrogels in immunodeficient mice would both induce a fibrin-driven angiogenic host response and promote in situ AFSC-derived neovascularization. Two weeks postinjection, hydrogels were sectioned, and the following was demonstrated: the average maximum invasion distance of host murine cells into the subcutaneous fibrin/PEG scaffold was 147 ± 90 µm after 1 week and 395 ± 138 µm after 2 weeks; the average number of cell-lined lumen per square millimeter was significantly higher in hydrogels seeded with stem cells or cocultures containing stem cells (MSC, 36.5 ± 11.4; AFSC, 47.0 ± 18.9; AFSC/AFSC-EC, 32.8 ± 11.6; and MSC/HUVEC, 43.1 ± 25.1) versus endothelial cell types alone (AFSC-EC, 9.7 ± 6.1; HUVEC, 14.2 ± 8.8); and a subset of these lumen were characterized by the presence of red blood cells. Select areas of cell-seeded hydrogels contained CD31(+) lumen surrounded by α-smooth muscle cell support cells, whereas control hydrogels with no cells only showed infiltration of α-smooth muscle cell-positive host cells.

  14. In Vitro Evaluation of Scaffolds for the Delivery of Mesenchymal Stem Cells to Wounds

    PubMed Central

    Wahl, Elizabeth A.; Fierro, Fernando A.; Peavy, Thomas R.; Hopfner, Ursula; Dye, Julian F.; Machens, Hans-Günther; Egaña, José T.; Schenck, Thilo L.

    2015-01-01

    Mesenchymal stem cells (MSCs) have been shown to improve tissue regeneration in several preclinical and clinical trials. These cells have been used in combination with three-dimensional scaffolds as a promising approach in the field of regenerative medicine. We compare the behavior of human adipose-derived MSCs (AdMSCs) on four different biomaterials that are awaiting or have already received FDA approval to determine a suitable regenerative scaffold for delivering these cells to dermal wounds and increasing healing potential. AdMSCs were isolated, characterized, and seeded onto scaffolds based on chitosan, fibrin, bovine collagen, and decellularized porcine dermis. In vitro results demonstrated that the scaffolds strongly influence key parameters, such as seeding efficiency, cellular distribution, attachment, survival, metabolic activity, and paracrine release. Chick chorioallantoic membrane assays revealed that the scaffold composition similarly influences the angiogenic potential of AdMSCs in vivo. The wound healing potential of scaffolds increases by means of a synergistic relationship between AdMSCs and biomaterial resulting in the release of proangiogenic and cytokine factors, which is currently lacking when a scaffold alone is utilized. Furthermore, the methods used herein can be utilized to test other scaffold materials to increase their wound healing potential with AdMSCs. PMID:26504774

  15. A CCR2 macrophage endocytic pathway mediates extravascular fibrin clearance in vivo.

    PubMed

    Motley, Michael P; Madsen, Daniel H; Jürgensen, Henrik J; Spencer, David E; Szabo, Roman; Holmbeck, Kenn; Flick, Matthew J; Lawrence, Daniel A; Castellino, Francis J; Weigert, Roberto; Bugge, Thomas H

    2016-03-01

    Extravascular fibrin deposition accompanies many human diseases and causes chronic inflammation and organ damage, unless removed in a timely manner. Here, we used intravital microscopy to investigate how fibrin is removed from extravascular space. Fibrin placed into the dermis of mice underwent cellular endocytosis and lysosomal targeting, revealing a novel intracellular pathway for extravascular fibrin degradation. A C-C chemokine receptor type 2 (CCR2)-positive macrophage subpopulation constituted the majority of fibrin-uptaking cells. Consequently, cellular fibrin uptake was diminished by elimination of CCR2-expressing cells. The CCR2-positive macrophage subtype was different from collagen-internalizing M2-like macrophages. Cellular fibrin uptake was strictly dependent on plasminogen and plasminogen activator. Surprisingly, however, fibrin endocytosis was unimpeded by the absence of the fibrin(ogen) receptors, αMβ2 and ICAM-1, the myeloid cell integrin-binding site on fibrin or the endocytic collagen receptor, the mannose receptor. The study identifies a novel fibrin endocytic pathway engaged in extravascular fibrin clearance and shows that interstitial fibrin and collagen are cleared by different subsets of macrophages employing distinct molecular pathways. PMID:26647393

  16. Fibronectin alters the rate of formation and structure of the fibrin matrix.

    PubMed

    Ramanathan, Anand; Karuri, Nancy

    2014-01-10

    Plasma fibronectin is a vital component of the fibrin clot; however its role on clot structure is not clearly understood. The goal of this study was to examine the influence of fibronectin on the kinetics of formation, structural characteristics and composition of reconstituted fibrin clots or fibrin matrices. Fibrin matrices were formed by adding thrombin to 1, 2 or 4 mg/ml fibrinogen supplemented with 0-0.4 mg/ml fibronectin. The rate of fibrin matrix formation was then monitored by measuring light absorbance properties at different time points. Confocal microscopy of fluorescein conjugated fibrinogen was used to visualize the structural characteristics of fibrin matrices. The amount of fibronectin in fibrin matrices was determined through electrophoresis and immunoblotting of solubilized matrices. Fibronectin concentration positively correlated with the initial rate of fibrin matrix formation and with steady state light absorbance values of fibrin matrices. An increase in fibronectin concentration resulted in thinner and denser fibers in the fibrin matrices. Electrophoresis and immunoblotting showed that fibronectin was covalently and non-covalently bound to fibrin matrices and in the form of high molecular weight multimers. The formation of fibronectin multimers was attributed to cross-linking of fibronectin by trace amounts Factor XIIIa. These findings are novel because they link results from light absorbance studies to microcopy analyses and demonstrate an influence of fibronectin on fibrin matrix structural characteristics. This data is important in developing therapies that destabilize fibrin clots.

  17. A CCR2 macrophage endocytic pathway mediates extravascular fibrin clearance in vivo

    PubMed Central

    Motley, Michael P.; Madsen, Daniel H.; Jürgensen, Henrik J.; Spencer, David E.; Szabo, Roman; Holmbeck, Kenn; Flick, Matthew J.; Lawrence, Daniel A.; Castellino, Francis J.; Weigert, Roberto

    2016-01-01

    Extravascular fibrin deposition accompanies many human diseases and causes chronic inflammation and organ damage, unless removed in a timely manner. Here, we used intravital microscopy to investigate how fibrin is removed from extravascular space. Fibrin placed into the dermis of mice underwent cellular endocytosis and lysosomal targeting, revealing a novel intracellular pathway for extravascular fibrin degradation. A C-C chemokine receptor type 2 (CCR2)-positive macrophage subpopulation constituted the majority of fibrin-uptaking cells. Consequently, cellular fibrin uptake was diminished by elimination of CCR2-expressing cells. The CCR2-positive macrophage subtype was different from collagen-internalizing M2-like macrophages. Cellular fibrin uptake was strictly dependent on plasminogen and plasminogen activator. Surprisingly, however, fibrin endocytosis was unimpeded by the absence of the fibrin(ogen) receptors, αMβ2 and ICAM-1, the myeloid cell integrin-binding site on fibrin or the endocytic collagen receptor, the mannose receptor. The study identifies a novel fibrin endocytic pathway engaged in extravascular fibrin clearance and shows that interstitial fibrin and collagen are cleared by different subsets of macrophages employing distinct molecular pathways. PMID:26647393

  18. Failure mechanisms of fibrin-based surgical tissue adhesives

    NASA Astrophysics Data System (ADS)

    Sierra, David Hugh

    A series of studies was performed to investigate the potential impact of heterogeneity in the matrix of multiple-component fibrin-based tissue adhesives upon their mechanical and biomechanical properties both in vivo and in vitro. Investigations into the failure mechanisms by stereological techniques demonstrated that heterogeneity could be measured quantitatively and that the variation in heterogeneity could be altered both by the means of component mixing and delivery and by the formulation of the sealant. Ex vivo tensile adhesive strength was found to be inversely proportional to the amount of heterogeneity. In contrast, in vivo tensile wound-closure strength was found to be relatively unaffected by the degree of heterogeneity, while in vivo parenchymal organ hemostasis in rabbits was found to be affected: greater heterogeneity appeared to correlate with an increase in hemostasis time and amount of sealant necessary to effect hemostasis. Tensile testing of the bulk sealant showed that mechanical parameters were proportional to fibrin concentration and that the physical characteristics of the failure supported a ductile mechanism. Strain hardening as a function of percentage of strain, and strain rate was observed for both concentrations, and syneresis was observed at low strain rates for the lower fibrin concentration. Blister testing demonstrated that burst pressure and failure energy were proportional to fibrin concentration and decreased with increasing flow rate. Higher fibrin concentration demonstrated predominately compact morphology debonds with cohesive failure loci, demonstrating shear or viscous failure in a viscoelastic rubbery adhesive. The lower fibrin concentration sealant exhibited predominately fractal morphology debonds with cohesive failure loci, supporting an elastoviscous material condition. The failure mechanism for these was hypothesized and shown to be flow-induced ductile fracture. Based on these findings, the failure mechanism was

  19. Ultrastructural changes to rabbit fibrin and platelets due to aspartame.

    PubMed

    Pretorius, E; Humphries, P

    2007-01-01

    The coagulation process, including thrombin, fibrin, as well as platelets, plays an important role in hemostasis, contributing to the general well-being of humans. Fibrin formation and platelet activation are delicate processes that are under the control of many small physiological events. Any one of these many processes may be influenced or changed by external factors, including pharmaceutical or nutritional products, e.g., the sweetener aspartame (L-aspartyl-L-phenylalanine methyl ester). It is known that phenylalanine is present at position P(9) and aspartate at position P(10) of the alpha-chain of human fibrinogen, and plays an important role in the conversion of fibrinogen to fibrin by the catalyst alpha-thrombin. The authors investigate the effect of aspartame on platelet and fibrin ultrastructure, by using the rabbit animal model and the scanning electron microscope. Animals were exposed to 34 mg/kg of aspartame 26x during a 2-month period. Aspartame-exposed fibrin networks appeared denser, with a thick matted fine fiber network covering thick major fibers. Also, the platelet aggregates appeared more granular than the globular control platelet aggregates. The authors conclude by suggesting that aspartame usage may interfere with the coagulation process and might cause delayed fibrin breakup after clot formation. They suggest this, as the fibrin networks from aspartame-exposed rabbits are more complex and dense, due to the netlike appearance of the minor, thin fibers. Aspartame usage should possibly be limited by people on anti-clotting medicine or those with prone to clot formation.

  20. Nano-thrombelastography of fibrin during blood plasma clotting.

    PubMed

    Feller, Tímea; Kellermayer, Miklós S Z; Kiss, Balázs

    2014-06-01

    Hemostasis is a complex process that relies on the sensitive balance between the formation and breakdown of the thrombus, a three-dimensional polymer network of the fibrous protein fibrin. Neither the details of the fibrinogen-fibrin transition, nor the exact mechanisms of fibrin degradation are fully understood at the molecular level. In the present work we investigated the nanoscale-changes in the viscoelasticity of the 3D-fibrin network during fibrinogenesis and streptokinase (STK)-induced fibrinolysis by using a novel application of force spectroscopy, named nano-thrombelastography. In this method the changes in the bending of an oscillating atomic-force-microscope (AFM) cantilever in human blood-plasma droplet were followed as a function of time. Whereas the global features of the time-dependent change in cantilever deflection corresponded well to a macroscopic thrombelastogram, the underlying force spectra revealed large, sample-dependent oscillations in the range of 3-50nN and allowed the separation of elastic and viscous components of fibrin behavior. Upon STK treatment the nano-thrombelastogram signal decayed gradually. The decay was driven by a decrease in thrombus elasticity, whereas thrombus viscosity decayed with a time delay. In scanning AFM images mature fibrin appeared as 17-nm-high and 12-196-nm-wide filaments. STK-treatment resulted in the decrease of filament height and the appearance of a surface roughness with 23.7nm discrete steps that corresponds well to the length of a fibrinogen monomer. Thus, the initial decay of thrombus elasticity during fibrinolysis may be caused by the axial rupture of fibrin fibers. PMID:24736106

  1. Evaluation of gold nanotracers to track adipose-derived stem cells in a PEGylated fibrin gel for dermal tissue engineering applications

    PubMed Central

    Chung, Eunna; Nam, Seung Yun; Ricles, Laura M; Emelianov, Stanislav Y; Suggs, Laura J

    2013-01-01

    Evaluating the regenerative capacity of a tissue-engineered device in a noninvasive and synchronous manner is critical to determining the mechanisms for success in clinical applications. In particular, directly tracking implanted cells in a three-dimensional (3D) scaffold is desirable in that it enables the monitoring of cellular activity in a specific and localized manner. The authors’ group has previously demonstrated that the PEGylation of fibrin results in a 3D scaffold that supports morphologic and phenotypic changes in mesenchymal stem cells that may be advantageous in wound healing applications. Recently, the authors have evaluated adipose-derived stem cells (ASCs) as a mesenchymal cell source to regenerate skin and blood vessels due to their potential for proliferation, differentiation, and production of growth factors. However, tracking and monitoring ASCs in a 3D scaffold, such as a PEGylated fibrin gel, have not yet been fully investigated. In the current paper, nanoscale gold spheres (20 nm) as cell tracers for ASCs cultured in a PEGylated fibrin gel were evaluated. An advanced dual-imaging modality combining ultrasound and photoacoustic imaging was utilized to monitor rat ASCs over time. The ASCs took up gold nanotracers and could be detected up to day 16 with high sensitivity using photoacoustic imaging. There were no detrimental effects on ASC morphology, network formation, proliferation, and protein expression/secretion (ie, smooth muscle α-actin, vascular endothelial growth factor, matrix metalloproteinase-2, and matrix metalloproteinase-9) associated with gold nanotracers. Therefore, utilization of gold nanotracers can be an effective strategy to monitor the regenerative process of a stem cell source in a 3D gel for vascular and dermal tissue engineering applications. PMID:23345978

  2. Evaluation of gold nanotracers to track adipose-derived stem cells in a PEGylated fibrin gel for dermal tissue engineering applications.

    PubMed

    Chung, Eunna; Nam, Seung Yun; Ricles, Laura M; Emelianov, Stanislav Y; Suggs, Laura J

    2013-01-01

    Evaluating the regenerative capacity of a tissue-engineered device in a noninvasive and synchronous manner is critical to determining the mechanisms for success in clinical applications. In particular, directly tracking implanted cells in a three-dimensional (3D) scaffold is desirable in that it enables the monitoring of cellular activity in a specific and localized manner. The authors' group has previously demonstrated that the PEGylation of fibrin results in a 3D scaffold that supports morphologic and phenotypic changes in mesenchymal stem cells that may be advantageous in wound healing applications. Recently, the authors have evaluated adipose-derived stem cells (ASCs) as a mesenchymal cell source to regenerate skin and blood vessels due to their potential for proliferation, differentiation, and production of growth factors. However, tracking and monitoring ASCs in a 3D scaffold, such as a PEGylated fibrin gel, have not yet been fully investigated. In the current paper, nanoscale gold spheres (20 nm) as cell tracers for ASCs cultured in a PEGylated fibrin gel were evaluated. An advanced dual-imaging modality combining ultrasound and photoacoustic imaging was utilized to monitor rat ASCs over time. The ASCs took up gold nanotracers and could be detected up to day 16 with high sensitivity using photoacoustic imaging. There were no detrimental effects on ASC morphology, network formation, proliferation, and protein expression/secretion (ie, smooth muscle α-actin, vascular endothelial growth factor, matrix metalloproteinase-2, and matrix metalloproteinase-9) associated with gold nanotracers. Therefore, utilization of gold nanotracers can be an effective strategy to monitor the regenerative process of a stem cell source in a 3D gel for vascular and dermal tissue engineering applications.

  3. Stroke from Delayed Embolization of Polymerized Glue Following Percutaneous Direct Injection of a Carotid Body Tumor

    PubMed Central

    Gupta, Arun Kumar; Rajan, Jayadevan E; Thomas, Bejoy

    2007-01-01

    A 52-year-old male with right carotid body tumor underwent direct percutaneous glue (n-butylcyanoacrylate [NBCA]) embolization. Several hours later, he developed left hemiparesis from embolization of the polymerized glue cast. Migration of glue during percutaneous tumor embolization is presumed to occur only in the liquid state, which may lead to stroke or cranial nerve deficits. To the best of our knowledge, this is the first report of delayed glue embolization from a treated hypervascular tumor of the head and neck. PMID:17554195

  4. Stroke from delayed embolization of polymerized glue following percutaneous direct injection of a carotid body tumor.

    PubMed

    Krishnamoorthy, Thamburaj; Gupta, Arun Kumar; Rajan, Jayadevan E; Thomas, Bejoy

    2007-01-01

    A 52-year-old male with right carotid body tumor underwent direct percutaneous glue (n-butylcyanoacrylate [NBCA]) embolization. Several hours later, he developed left hemiparesis from embolization of the polymerized glue cast. Migration of glue during percutaneous tumor embolization is presumed to occur only in the liquid state, which may lead to stroke or cranial nerve deficits. To the best of our knowledge, this is the first report of delayed glue embolization from a treated hypervascular tumor of the head and neck.

  5. Glue embolus complicating the endovascular treatment of a patient with Loeys-Dietz syndrome.

    PubMed

    Marine, Leopoldo; Gupta, Rishi; Gornik, Heather L; Kashyap, Vikram S

    2010-11-01

    A 34-year-old [corrected] woman was diagnosed with Loeys-Dietz syndrome. Five months later, the patient presented with a symptomatic 2.6-cm subclavian pseudoaneurysm. Staged endovascular treatment was initiated with left vertebral artery embolization, followed by sac ablation and stent graft exclusion. The pseudoaneurysm cavity was filled with n-butylcyanoacrylate ("glue") via a microcatheter. Despite balloon occlusion of the pseudoaneurysm orifice, a small amount of glue debris embolized to the brachial artery, necessitating a vein bypass. In this case, distal embolization of glue may have been avoided by leaving a microcatheter in the aneurysm sac for glue injection after first deploying the stent graft.

  6. Compounds from Silicones Alter Enzyme Activity in Curing Barnacle Glue and Model Enzymes

    PubMed Central

    Rittschof, Daniel; Orihuela, Beatriz; Harder, Tilmann; Stafslien, Shane; Chisholm, Bret; Dickinson, Gary H.

    2011-01-01

    Background Attachment strength of fouling organisms on silicone coatings is low. We hypothesized that low attachment strength on silicones is, in part, due to the interaction of surface available components with natural glues. Components could alter curing of glues through bulk changes or specifically through altered enzyme activity. Methodology/Principal Findings GC-MS analysis of silicone coatings showed surface-available siloxanes when the coatings were gently rubbed with a cotton swab for 15 seconds or given a 30 second rinse with methanol. Mixtures of compounds were found on 2 commercial and 8 model silicone coatings. The hypothesis that silicone components alter glue curing enzymes was tested with curing barnacle glue and with commercial enzymes. In our model, barnacle glue curing involves trypsin-like serine protease(s), which activate enzymes and structural proteins, and a transglutaminase which cross-links glue proteins. Transglutaminase activity was significantly altered upon exposure of curing glue from individual barnacles to silicone eluates. Activity of purified trypsin and, to a greater extent, transglutaminase was significantly altered by relevant concentrations of silicone polymer constituents. Conclusions/Significance Surface-associated silicone compounds can disrupt glue curing and alter enzyme properties. Altered curing of natural glues has potential in fouling management. PMID:21379573

  7. Platelet rich fibrin in jaw defects

    NASA Astrophysics Data System (ADS)

    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.

  8. Fibrin(ogen)olytic activity of bumblebee venom serine protease

    SciTech Connect

    Qiu Yuling; Choo, Young Moo; Yoon, Hyung Joo; Jia Jingming; Cui Zheng; Wang Dong; Kim, Doh Hoon; Sohn, Hung Dae; Jin, Byung Rae

    2011-09-01

    Bee venom is a rich source of pharmacologically active components; it has been used as an immunotherapy to treat bee venom hypersensitivity, and venom therapy has been applied as an alternative medicine. Here, we present evidence that the serine protease found in bumblebee venom exhibits fibrin(ogen)olytic activity. Compared to honeybee venom, bumblebee venom contains a higher content of serine protease, which is one of its major components. Venom serine proteases from bumblebees did not cross-react with antibodies against the honeybee venom serine protease. We provide functional evidence indicating that bumblebee (Bombus terrestris) venom serine protease (Bt-VSP) acts as a fibrin(ogen)olytic enzyme. Bt-VSP activates prothrombin and directly degrades fibrinogen into fibrin degradation products. However, Bt-VSP is not a plasminogen activator, and its fibrinolytic activity is less than that of plasmin. Taken together, our results define roles for Bt-VSP as a prothrombin activator, a thrombin-like protease, and a plasmin-like protease. These findings offer significant insight into the allergic reaction sequence that is initiated by bee venom serine protease and its potential usefulness as a clinical agent in the field of hemostasis and thrombosis. - Graphical abstract: Display Omitted Highlights: > Bumblebee venom serine protease (Bt-VSP) is a fibrin(ogen)olytic enzyme. > Bt-VSP activates prothrombin. > Bt-VSP directly degrades fibrinogen into fibrin degradation products. > Bt-VSP is a hemostatically active protein that is a potent clinical agent.

  9. Phase-separated chitosan–fibrin microbeads for cell delivery

    PubMed Central

    Chen, Zhewei; Wang, Limin; Stegemann, Jan P.

    2011-01-01

    Matrix-enhanced delivery of cells is a promising approach to improving current cell therapies. Our objective was to create cell-laden composite microbeads that combine the attractive features of the natural polymers chitosan and fibrin. Liquid polydimethylsiloxane was used to emulsify a chitosan–fibrinogen solution containing suspended human fibroblast cells, followed by initiation of thrombin-mediated polymerization of fibrin and thermal/pH-mediated gelation of chitosan. Chitosan/fibrin weight percent (wt%) ratios of 100/0, 75/25, 50/50 and 25/75 were investigated. Microbead diameters ranged from 275 ± 99 μm to 38 ± 10 μm using impeller speeds from 600 to 1400 rpm. Fibroblasts remained viable on day 1 post-fabrication in all matrices, but cell viability was markedly higher in high-fibrin microbeads by day 8 post-fabrication. Cell spreading and interaction with the extracellular matrix was also markedly increased in high-fibrin matrices. Such composite microbeads containing viable entrapped cells have potential for minimally invasive delivery of cells for a variety of tissue repair applications. PMID:21736519

  10. Measurement of fibrin concentration by fast field-cycling NMR.

    PubMed

    Broche, Lionel M; Ismail, Saadiya R; Booth, Nuala A; Lurie, David J

    2012-05-01

    The relaxation of (1)H nuclei due to their interaction with quadrupolar (14)N nuclei in gel structures is measured using fast field-cycling NMR. This phenomenon called quadrupolar dips has been reported in different (1)H-(14)N bond-rich species. In this study, we have studied quadrupolar dips in fibrin, an insoluble protein that is the core matrix of thrombi. Fibrin was formed by the addition of thrombin to fibrinogen in 0.2% agarose gel. T(1)-dispersion curves were measured using fast field-cycling NMR relaxometry, over the field range of 1.5-3.5 MHz (proton Larmor frequency), and were analyzed using a curve-fitting algorithm. A linear increase of signal amplitude with increasing fibrin concentration was observed. This agrees with the current theory that predicts a linear relationship of signal amplitude with the concentration of contributing (14)N spins in the sample. Interestingly, fibrin formation gave rise to the signal, regardless of crosslinking induced by the transglutaminase factor XIIIa. To investigate the effect of proteins that might be trapped in the thrombi in vivo, the plasma protein albumin was added to the fibrin gel, and an increase in the quadrupolar signal amplitude was observed. This study can potentially be useful for thrombi classification by fast field-cycling MRI techniques.

  11. Biomimetic magnetic silk scaffolds.

    PubMed

    Samal, Sangram K; Dash, Mamoni; Shelyakova, Tatiana; Declercq, Heidi A; Uhlarz, Marc; Bañobre-López, Manuel; Dubruel, Peter; Cornelissen, Maria; Herrmannsdörfer, Thomas; Rivas, Jose; Padeletti, Giuseppina; De Smedt, Stefaan; Braeckmans, Kevin; Kaplan, David L; Dediu, V Alek

    2015-03-25

    Magnetic silk fibroin protein (SFP) scaffolds integrating magnetic materials and featuring magnetic gradients were prepared for potential utility in magnetic-field assisted tissue engineering. Magnetic nanoparticles (MNPs) were introduced into SFP scaffolds via dip-coating methods, resulting in magnetic SFP scaffolds with different strengths of magnetization. Magnetic SFP scaffolds showed excellent hyperthermia properties achieving temperature increases up to 8 °C in about 100 s. The scaffolds were not toxic to osteogenic cells and improved cell adhesion and proliferation. These findings suggest that tailored magnetized silk-based biomaterials can be engineered with interesting features for biomaterials and tissue-engineering applications.

  12. Versatile modular scaffolds

    NASA Technical Reports Server (NTRS)

    Kerley, J.

    1981-01-01

    Movable and fixed modular scaffolds can be tailored to most scaffolding needs by interconnecting only 4 basic structural elements: platforms, rails, vertical-support angles, and stiffener. Standard nuts and bolts are used to join elements, simplifying construction, and reducing costs. Scaffolds are rigid and can be made any length. They are stable on unlevel ground and can extend to well over 50 feet in height. Scaffolds allow for internal elevators and for wheels and air mounts so that same elements can be used for standing or movable scaffold.

  13. Fibrin network pattern changes of platelet-rich fibrin in young versus old age group of individuals: A cell block cytology study

    PubMed Central

    Yajamanya, Shravanthi Raghav; Chatterjee, Anirban; Babu, Chaitanya Nischay; Karunanithi, Deepika

    2016-01-01

    Background: To evaluate variations in fibrin network patterns of the platelet-rich fibrin (PRF) in different age groups. Materials and Methods: Ninety-five patients were divided into three age groups: Group 1: (20–39 years); Group 2: (40–59 years); and Group 3: (60 years and above). PRF was prepared from blood samples of all patients and were subjected to cell block cytology method of histological analysis and slides were prepared to histologically assess the age-related changes in (i) fibrin network patterns in terms of density and (ii) entrapment of platelets and white blood cells (WBCs) within fibrin meshwork. Results: Two types of fibrin network pattern arrangements noticed: Dense and loose types in three age groups. However, there was a noticeable decrease in the dense type of fibrin network with progressing age and increase in the loose type of fibrin arrangement. Furthermore, variation in a number of platelets and WBCs entrapped within fibrin network in relation to age was noticed. Conclusion: From the current study it can be concluded that age can be considered as one of the influencing factors on quality of PRF in terms of fibrin network patterns and hence, platelet and WBCs entrapment within these fibrin networks. PMID:27143826

  14. Hemostasis during urologic surgery: fibrin sealant compared with absorbable hemostat.

    PubMed

    Albala, David M; Riebman, Jerome B; Kocharian, Richard; Ilie, Bogdan; Albanese, John; Shen, Jessica; Ovington, Liza; Batiller, Jonathan

    2015-01-01

    In the United States, fibrin sealants have been used to achieve hemostasis for nearly two decades. Although their clinical utility was first demonstrated in cardiac surgery, their effectiveness and safety have since been demonstrated to extend to a wide array of procedures. Fibrin sealants typically contain two components-fibrinogen and thrombin-that are combined and delivered simultaneously to a target bleeding site in order to achieve hemostasis. However, many commercial formulations contain other additional components, such as antifibrinolytic agents, that have been associated with adverse outcomes. This subanalysis compares the safety and effectiveness of a fibrin sealant versus an absorbable hemostat for achieving hemostasis during urologic procedures with mild to moderate bleeding. PMID:26028998

  15. Fibrin self-assembly is adapted to oxidation.

    PubMed

    Rosenfeld, Mark A; Bychkova, Anna V; Shchegolikhin, Alexander N; Leonova, Vera B; Kostanova, Elizaveta A; Biryukova, Marina I; Sultimova, Natalia B; Konstantinova, Marina L

    2016-06-01

    Fibrinogen is extremely susceptible to attack by reactive oxygen species (ROS). Having been suffered an oxidative modification, the fibrinogen molecules, now with altered spatial structure and function of fibrin network, affect hemostasis differently. However, the potential effects of the oxidative stress on the early stages of the fibrin self-assembly process remain unexplored. To clarify the damaging influence of ROS on the knob 'A': hole 'a' and the D:D interactions, the both are operating on the early stages of the fibrin polymerization, we have used a novel approach based on exploration of FXIIIa-mediated self-assembly of the cross-linked fibrin oligomers dissolved in the moderately concentrated urea solutions. The oligomers were composed of monomeric desA fibrin molecules created by cleaving the fibrinopeptides A off the fibrinogen molecules with a thrombin-like enzyme, reptilase. According to the UV-absorbance and fluorescence measurements data, the employed low ozone/fibrinogen ratios have induced only a slight fibrinogen oxidative modification that was accompanied by modest chemical transformations of the aromatic amino acid residues of the protein. Else, a slight consumption of the accessible tyrosine residues has been observed due to intermolecular dityrosine cross-links formation. The set of experimental data gathered with the aid of electrophoresis, elastic light scattering and analytical centrifugation has clearly witnessed that the oxidation can serve as an effective promoter for the observed enhanced self-assembly of the covalently cross-linked oligomers. At urea concentration of 1.20M, the pristine and oxidized fibrin oligomers were found to comprise a heterogeneous set of the double-stranded protofibrils that are cross-linked only by γ-γ dimers and the fibers consisting on average of four strands that are additionally linked by α polymers. The amounts of the oxidized protofibrils and the fibers accumulated in the system were higher than those

  16. [Adjusting gingival tissues morphology after dental implantation with fibrin use].

    PubMed

    Maĭborodin, I V; Kolesnikov, I S; Sheplev, B V; Ragimova, T M; Kovyntsev, A N; Kovyntsev, D N; Shevela, A I

    2009-01-01

    In gingival tissues of 62 patients after dental implantation of traditional type and with the use of thrombocyte rich fibrin preparation (TRFP) microcirculation and leucocytal infiltration were studied. It was disclosed that in all terms after titanium screw dental implant setting lymphostasis and leucocytal infiltration were seen as signs of active inflammatory process in gingival tissues. 3 months later after implants setting with the use of TRFP the lymphatic vessels status was normalized, the degree of leucocytal infiltration was reduced; when implantation was made without use of fibrin technologies in gingival tissues more leucocytes were found and lymphatic bed components were remained dilated. Besides fibrin preparation use in the process of dental implantation promoted quicker and stronger implant fixation, but granulomatous inflammatory process could develop and amount of eosinophils in gingival tissues could also increased. PMID:19365340

  17. Fibrin self-assembly is adapted to oxidation.

    PubMed

    Rosenfeld, Mark A; Bychkova, Anna V; Shchegolikhin, Alexander N; Leonova, Vera B; Kostanova, Elizaveta A; Biryukova, Marina I; Sultimova, Natalia B; Konstantinova, Marina L

    2016-06-01

    Fibrinogen is extremely susceptible to attack by reactive oxygen species (ROS). Having been suffered an oxidative modification, the fibrinogen molecules, now with altered spatial structure and function of fibrin network, affect hemostasis differently. However, the potential effects of the oxidative stress on the early stages of the fibrin self-assembly process remain unexplored. To clarify the damaging influence of ROS on the knob 'A': hole 'a' and the D:D interactions, the both are operating on the early stages of the fibrin polymerization, we have used a novel approach based on exploration of FXIIIa-mediated self-assembly of the cross-linked fibrin oligomers dissolved in the moderately concentrated urea solutions. The oligomers were composed of monomeric desA fibrin molecules created by cleaving the fibrinopeptides A off the fibrinogen molecules with a thrombin-like enzyme, reptilase. According to the UV-absorbance and fluorescence measurements data, the employed low ozone/fibrinogen ratios have induced only a slight fibrinogen oxidative modification that was accompanied by modest chemical transformations of the aromatic amino acid residues of the protein. Else, a slight consumption of the accessible tyrosine residues has been observed due to intermolecular dityrosine cross-links formation. The set of experimental data gathered with the aid of electrophoresis, elastic light scattering and analytical centrifugation has clearly witnessed that the oxidation can serve as an effective promoter for the observed enhanced self-assembly of the covalently cross-linked oligomers. At urea concentration of 1.20M, the pristine and oxidized fibrin oligomers were found to comprise a heterogeneous set of the double-stranded protofibrils that are cross-linked only by γ-γ dimers and the fibers consisting on average of four strands that are additionally linked by α polymers. The amounts of the oxidized protofibrils and the fibers accumulated in the system were higher than those

  18. Characterization of Leukocyte-platelet Rich Fibrin, A Novel Biomaterial.

    PubMed

    Madurantakam, Parthasarathy; Yoganarasimha, Suyog; Hasan, Fadi K

    2015-09-29

    Autologous platelet concentrates represent promising innovative tools in the field of regenerative medicine and have been extensively used in oral surgery. Unlike platelet rich plasma (PRP) that is a gel or a suspension, Leukocyte-Platelet Rich Fibrin (L-PRF) is a solid 3D fibrin membrane generated chair-side from whole blood containing no anti-coagulant. The membrane has a dense three dimensional fibrin matrix with enriched platelets and abundant growth factors. L-PRF is a popular adjunct in surgeries because of its superior handling characteristics as well as its suturability to the wound bed. The goal of the study is to demonstrate generation as well as provide detailed characterization of relevant properties of L-PRF that underlie its clinical success.

  19. The GlueX central drift chamber: Design and performance

    SciTech Connect

    Van Haarlem, Y; Barbosa, F; Dey, B; Lawrence, D; Razmyslovich, V; Smith, Visser; Whitlatch, T; Wilkin, G; Zihlmann, B

    2010-10-01

    Tests and studies concerning the design and performance of the GlueX Central Drift Chamber (CDC) are presented. A full-scale prototype was built to test and steer the mechanical and electronic design. Small scale prototypes were constructed to test for sagging and to do timing and resolution studies of the detector. These studies were used to choose the gas mixture and to program a Monte Carlo simulation that can predict the detector response in an external magnetic field. Particle identification and charge division possibilities were also investigated.

  20. Silicon photomultiplier characterization for the GlueX barrel calorimeter

    SciTech Connect

    F. Barbosa, J.E. McKisson, J. McKisson, Y. Qiang, E. Smith, C. Zorn

    2012-12-01

    GlueX is a new detector being constructed at Jefferson Laboratory to study gluonic excitations and confinement via the detection of exotic meson states. The hermetic detector includes a barrel calorimeter where the photodetectors must operate in a high magnetic field exceeding 0.5 T. After extensive tests with a variety of sensors, the chosen photodetector will be a custom silicon photomultiplier (SiPM) array manufactured by Hamamatsu Corporation. This paper will focus on the characterization of the first 80 production samples of these SiPMs, including dark rate, photodetection efficiency (PDE), crosstalk, response uniformity and radiation tolerance.

  1. First results from the GlueX experiment

    NASA Astrophysics Data System (ADS)

    Al Ghoul, H.; Anassontzis, E. G.; Barbosa, F.; Barnes, A.; Beattie, T. D.; Bennett, D. W.; Berdnikov, V. V.; Black, T.; Boeglin, W.; Brooks, W. K.; Cannon, B.; Chernyshov, O.; Chudakov, E.; Crede, V.; Dalton, M. M.; Deur, A.; Dobbs, S.; Dolgolenko, A.; Dugger, M.; Egiyan, H.; Eugenio, P.; Foda, A. M.; Frye, J.; Furletov, S.; Gan, L.; Gasparian, A.; Gerasimov, A.; Gevorgyan, N.; Goryachev, V. S.; Guegan, B.; Guo, L.; Hakobyan, H.; Hakobyan, H.; Hardin, J.; Huber, G. M.; Ireland, D.; Ito, M. M.; Jarvis, N. S.; Jones, R. T.; Kakoyan, V.; Kamel, M.; Klein, F. J.; Kourkoumeli, C.; Kuleshov, S.; Lara, M.; Larin, I.; Lawrence, D.; Leckey, J.; Levine, W. I.; Livingston, K.; Lolos, G. J.; Mack, D.; Mattione, P. T.; Matveev, V.; McCaughan, M.; McGinley, W.; McIntyre, J.; Mendez, R.; Meyer, C. A.; Miskimen, R.; Mitchell, R. E.; Mokaya, F.; Moriya, K.; Nigmatkulov, G.; Ochoa, N.; Ostrovidov, A. I.; Papandreou, Z.; Pedroni, R.; Pennington, M.; Pentchev, L.; Ponosov, A.; Pooser, E.; Pratt, B.; Qiang, Y.; Reinhold, J.; Ritchie, B. G.; Robison, L.; Romanov, D.; Salgado, C.; Schumacher, R. A.; Semenov, A. Yu.; Semenova, I. A.; Senderovich, I.; Seth, K. K.; Shepherd, M. R.; Smith, E. S.; Sober, D. I.; Somov, A.; Somov, S.; Soto, O.; Sparks, N.; Staib, M. J.; Stevens, J. R.; Subedi, A.; Tarasov, V.; Taylor, S.; Tolstukhin, I.; Tomaradze, A.; Toro, A.; Tsaris, A.; Vasileiadis, G.; Vega, I.; Voulgaris, G.; Walford, N. K.; Whitlatch, T.; Williams, M.; Wolin, E.; Xiao, T.; Zarling, J.; Zihlmann, B.

    2016-05-01

    The GlueX experiment at Jefferson Lab ran with its first commissioning beam in late 2014 and the spring of 2015. Data were collected on both plastic and liquid hydrogen targets, and much of the detector has been commissioned. All of the detector systems are now performing at or near design specifications and events are being fully reconstructed, including exclusive production of π0, η and ω mesons. Linearly-polarized photons were successfully produced through coherent bremsstrahlung and polarization transfer to the ρ has been observed.

  2. Egg Drop Competition Involving Only Toothpicks and Glue

    NASA Astrophysics Data System (ADS)

    Houpt, Stephen

    2004-04-01

    The Winston Science Egg Drop Competition is held annually in November, one of a large group of science competitions organized by Lehman Marks of the Winston School in Dallas, TX. The rules for the competition state that the egg package may be constructed of toothpicks and glue only, with a mass limit of 50 g, not including the egg. Once the egg is placed inside the package, it is dropped from a height of 8 m. The winning entry is the one that makes impact in the least amount of time while still protecting the egg. Timing is electronic.

  3. Fibrin activates GPVI in human and mouse platelets

    PubMed Central

    Alshehri, Osama M.; Montague, Samantha; Watson, Stephanie K.; Frampton, Jon; Bender, Markus; Watson, Steve P.

    2015-01-01

    The glycoprotein VI (GPVI)-Fc receptor γ (FcRγ) chain is the major platelet signaling receptor for collagen. Paradoxically, in a FeCl3 injury model, occlusion, but not initiation of thrombus formation, is delayed in GPVI-deficient and GPVI-depleted mice. In this study, we demonstrate that GPVI is a receptor for fibrin and speculate that this contributes to development of an occlusive thrombus. We observed a marked increase in tyrosine phosphorylation, including the FcRγ chain and Syk, in human and mouse platelets induced by thrombin in the presence of fibrinogen and the αIIbβ3 blocker eptifibatide. This was not seen in platelets stimulated by a protease activated receptor (PAR)-4 peptide, which is unable to generate fibrin from fibrinogen. The pattern of tyrosine phosphorylation was similar to that induced by activation of GPVI. Consistent with this, thrombin did not induce tyrosine phosphorylation of Syk and the FcRγ chain in GPVI-deficient mouse platelets. Mouse platelets underwent full spreading on fibrin but not fibrinogen, which was blocked in the presence of a Src kinase inhibitor or in the absence of GPVI. Spreading on fibrin was associated with phosphatidylserine exposure (procoagulant activity), and this too was blocked in GPVI-deficient platelets. The ectodomain of GPVI was shown to bind to immobilized monomeric and polymerized fibrin. A marked increase in embolization was seen following FeCl3 injury in GPVI-deficient mice, likely contributing to the delay in occlusion in this model. These results demonstrate that GPVI is a receptor for fibrin and provide evidence that this interaction contributes to thrombus growth and stability. PMID:26282541

  4. Use of fibrin sealant for reinforcing arterial anastomoses.

    PubMed

    Jakob, H; Campbell, C D; Qiu, Z K; Pick, R; Replogle, R L

    1984-01-01

    Despite improvements in needles, sutures, and technique, hemorrhage remains a problem in cardiovascular surgery. In this study conventional vascular suture lines and suture lines reinforced with fibrin sealant are compared for blood loss and burst strength. Bilateral femoral arteries in 20 dogs were divided at 50% of their circumference and repaired with six 6-0 polypropylene sutures. Ten animals were systemically heparinized (3 mg/kg), and 10 were not on anticoagulants. The right femoral artery anastomosis was treated with fibrin sealant in all animals, and the left suture line served as the control. Three minutes after initiation of the sealing procedure, blood flow was reinstituted in both femoral arteries. After 3 minutes a significant difference in blood loss between the conventional suture technique and fibrin-reinforced anastomoses was noted in both heparinized (12.1 +/- 2.79 vs. 0.13 +/- 0.06 ml/min; p less than 0.01) and nonheparinized dogs (8.45 +/- 1.37 vs. 0.20 +/- 0.08 ml/min; p less than 0.001). After 30 minutes volume inflow and pressure catheters were inserted into snared compartments encompassing the femoral artery anastomosis. Continuous pressure recordings during volume loading with normal saline solution demonstrated increased bursting pressures of the fibrin-sealed suture lines in both the heparinized (317.5 +/- 13.18 vs. 135 +/- 23.17 mm Hg; p less than 0.001) and nonheparinized animals (474.5 +/- 26.82 vs. 311 +/- 29.31 mm Hg; p less than 0.001). Histologic examination revealed no fibrosis or foreign body reaction and complete resorption of the fibrin sealant within 3 weeks. Fibrin sealant, a powerful hemostatic agent produced from human donors not suffering from hepatitis, decreases blood loss and strengthens suture lines.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Macroporous Three Dimensional PDMS Scaffolds for Extrahepatic Islet Transplantation

    PubMed Central

    Pedraza, Eileen; Brady, Ann-Christina; Fraker, Christopher A.; Molano, R. Damaris; Sukert, Steven; Berman, Dora M.; Kenyon, Norma S.; Pileggi, Antonello; Ricordi, Camillo; Stabler, Cherie L.

    2015-01-01

    Clinical islet transplantation has demonstrated success in treating type 1 diabetes. A current limitation is the intrahepatic portal vein transplant site, which is prone to mechanical stress and inflammation. Transplantation of pancreatic islets into alternative sites is preferable, but challenging, as it may require a three-dimensional vehicle to confer mechanical protection and to confine islets to a well-defined, retrievable space where islet neovascularization can occur. We have fabricated biostable, macroporous scaffolds from poly(dimethylsiloxane) (PDMS) and investigated islet retention and distribution, metabolic function, and glucose-dependent insulin secretion within these materials. Islets from multiple sources, including rodents, non-human primates, and humans, were tested in vitro. We observed high islet retention and distribution within PDMS scaffolds, with retention of small islets (< 100 µm) improved through the post-loading addition of fibrin gel. Islets loaded within PDMS scaffolds exhibited viability and function comparable to standard culture conditions when incubated under normal oxygen tensions, but displayed improved viability compared to standard two-dimensional culture controls under low oxygen tensions. In vivo efficacy of scaffolds to support islet grafts was evaluated after transplantation in the omental pouch of chemically-induced diabetic syngeneic rats, which promptly achieved normoglycemia. Collectively, these results are promising in that they indicate the potential for transplanting islets into a clinically relevant, extrahepatic site that provides spatial distribution of islets, as well as intra-device vascularization. PMID:23031502

  6. Optimization of a biomimetic poly-(lactic acid) ligament scaffold

    NASA Astrophysics Data System (ADS)

    Uehlin, Andrew F.

    The anterior cruciate ligament (ACL) is the most commonly injured ligament of the knee, often requiring orthopedic reconstruction using autograft or allograph tissue, both with significant disadvantages. As a result, tissue engineering an ACL replacement graft has been heavily investigated. The present study attempts to replicate the morphology and mechanical properties of the ACL using a nanomatrix composite of highly-aligned poly(lactic acid) (PLA) fibers with various surface and biochemical modifications. Additionally, this study attempts to recreate the natural mineralization gradient found at the ACL enthesis onto the scaffold, capable of inducing a favorable cellular response in vitro. Unidirectional electrospinning was used to create nanofibers of PLA, followed by an induced degradation of the nanofibers via 0.25M NaOH hydrolysis. The effects of the unidirectional electrospinning as well as the effects of NaOH hydrolysis on fiber alignment, fiber diameter, surface morphology, crystallinity, in vitro swelling, immobilization of fibrin, and mechanical properties were investigated, resulting in a modified morphology correlating to the microstructure of native ligament tissue with similar mechanical properties. Furthering the development of the PLA nanomatrix composite, a bioinkjet printer was used to immobilize nanoparticulate hydroxyapatite (HANP) on the surface of the scaffold. A series of 300pL droplets of HANP bioink were printed over a gradient pattern mimetic of (and spatially corresponding to) the mineralization gradient found over the microanatomy at the ACL enthesis. Proliferation and differentiation response of human mesenchymal stem cells (hMSCs) in vitro was assessed on a variety of conditions and combinations of the PLA nanofiber scaffold surface modifications (inclusive and exclusive of HANP, fibrin, and various time dependent NaOH treatments). It was found that a combinatory effect of the HANP gradient with fibrin on 20 minute NaOH treated PLA

  7. GLUE!: An Architecture for the Integration of External Tools in Virtual Learning Environments

    ERIC Educational Resources Information Center

    Alario-Hoyos, Carlos; Bote-Lorenzo, Miguel L.; Gomez-Sanchez, Eduardo; Asensio-Perez, Juan I.; Vega-Gorgojo, Guillermo; Ruiz-Calleja, Adolfo

    2013-01-01

    The integration of external tools in Virtual Learning Environments (VLEs) aims at enriching the learning activities that educational practitioners may design and enact. This paper presents GLUE!, an architecture that enables the lightweight integration of multiple existing external tools in multiple existing VLEs. GLUE! fosters this integration by…

  8. Spiritual and Religious Supports Part 8: Church G.L.U.E.

    ERIC Educational Resources Information Center

    Newman, Barbara J.

    2009-01-01

    CLC Network is an organization that partners with churches, schools, and families to help promote and build inclusive and interdependent communities for those with disabilities. This article describes CLC Network's most recent tool--a book entitled the G.L.U.E. Training Manual. G.L.U.E. is an adhesive process to allow each individual to be firmly…

  9. In vitro characterization of the technique of portal vein embolization by injection of a surgical glue

    NASA Astrophysics Data System (ADS)

    Salsac, Anne-Virginie; Sandulache, Mihai-Cristinel; Lancon, Oceane; El Kadri Benkara, Khadija

    2012-11-01

    Partial embolization of the portal trunk by glue injection is a minimally invasive technique used in the case of malignant liver tumors. It is conducted few weeks prior to partial liver ablation, when the volume of the remnant liver section is too small to allow hepatectomy. The limitation of glue embolotherapy is that its clinical practice is based on empirical knowledge. The present objective is to study glue injection in a confined blood flow and investigate how the injection dynamics is coupled with glue polymerization. We first characterize polymerization under static conditions for various glue concentrations and then consider the influence of injection. An experimental setup reproduces the co-flow of two immiscible fluids. The glue mixture is injected through a capillary tube into a saline solution with the same ionic concentration, pH and viscosity as blood, flowing steadily in a straight cylindrical tube. The injected phase is visualized with a high-speed imaging system and results are compared with those obtained for non-reacting fluids. These experiments have enabled us to characterize the characteristic times of polymerization of the glue mixtures under static and dynamic conditions and understand how they affect the flow topology of the glue once injected. Biomechanics and Bioengineering Laboratory (UMR CNRS 7338).

  10. Fibrin sealant-assisted revision of the exposed Ahmed tube.

    PubMed

    Choudhari, Nikhil S; Neog, Aditya; Latka, Supriya; Srinivasan, Bhaskar

    2015-01-01

    Tube exposure is a known complication of Ahmed glaucoma valve (AGV) implantation. Repair of the exposed tube is not easy. A 42-year-old monocular aphakic male had undergone retinal detachment repair with placement of an episcleral-encircling band followed by implantation of AGV. He presented to the clinic on routine review with exposure of the shunt tube. The complication was managed by placing scleral and conjunctival grafts over the exposed tube using a fibrin adhesive (Tisseel kit; Baxter AG, Vienna, Austria). The novel use of the fibrin sealant in the repair of AGV tube exposure was for better graft-integration.

  11. Fibrin Sealant-Assisted Revision of the Exposed Ahmed Tube

    PubMed Central

    Choudhari, Nikhil S.; Neog, Aditya; Latka, Supriya; Srinivasan, Bhaskar

    2015-01-01

    Tube exposure is a known complication of Ahmed glaucoma valve (AGV) implantation. Repair of the exposed tube is not easy. A 42-year-old monocular aphakic male had undergone retinal detachment repair with placement of an episcleral-encircling band followed by implantation of AGV. He presented to the clinic on routine review with exposure of the shunt tube. The complication was managed by placing scleral and conjunctival grafts over the exposed tube using a fibrin adhesive (Tisseel kit; Baxter AG, Vienna, Austria). The novel use of the fibrin sealant in the repair of AGV tube exposure was for better graft-integration. PMID:25624685

  12. Obstructive Fibrinous Tracheal Pseudomembrane After Tracheal Intubation: A Case Report

    PubMed Central

    Kang, Hyeon Hui; Kim, Jin Woo; Kang, Ji Young; Kim, Ju Sang; Kim, Myung Sook; Kim, Seung Su; Kim, Yong Hyun; Moon, Hwa Sik

    2010-01-01

    Obstructive fibrinous tracheal pseudomembrane is a rare, but potentially fatal complication associated with endotracheal intubation. It has been known that the formation of tracheal pseudomembrane is related with intracuff pressure during endotracheal intubation or infectious cause. But in the patient described in this case, pseudomembrane formation in the trachea was associated with subglottic epithelial trauma or caustic injuries to the trachea caused by aspirated gastric contents during intubation rather than tracheal ischemia due to high cuff pressure. We report a patient with obstructive fibrinous tracheal pseudomembrane after endotracheal intubation who presented with dyspnea and stridor and was treated successfully with mechanical removal using rigid bronchoscopy. PMID:20808687

  13. Research on Intelligent Glue-coating Robot Based on Visual Servo

    NASA Astrophysics Data System (ADS)

    Yang, Zhigang; An, Yi; Sun, Yanbin; Zhang, Jingchun

    At present, Glue-coating machines have some shortages, such as unintelligence, complexity of setting glue path for new parts. In this paper, real-time image capture was achieved by using digital camera technology and image processing technology. The captured image is converted into a character vector. Workpiece model is determined through comparing with the standard library and the similarity. The image of workpiece was vectored through frame extracting and fitting. With NC (Numerical Control) code generation technology, the NC code is automatically generated for sprinkler nozzle walking track. By Appling visual servo and embedding the vision system into feedback loop of the robot, the system achieves high-precision robot control. By extracting the glue line curve from image, thinning glue curve by morphological method, and extracting the frame information, the closure and quality of the glue curve can be detected. Results of test show that the effect is satisfactory and the method is effective.

  14. Evaluation of a soluble fibrin assay in patients with suspected pulmonary embolism.

    PubMed

    Ginsberg, J S; Siragusa, S; Douketis, J; Johnston, M; Moffat, K; Donovan, D; McGinnis, J; Brill-Edwards, P; Panju, A; Patel, A; Weitz, J I

    1996-04-01

    In order to determine the clinical utility of an enzyme immunoassay (EIA) for soluble fibrin in patients with suspected pulmonary embolism (PE), 195 unselected patients with suspected PE underwent blood sampling for measurement of plasma levels of soluble fibrin, and objective testing for PE. A soluble fibrin result of < or = 0.75 micrograms/ml showed a sensitivity of 100% for PE and a specificity of 12.8%, whereas a soluble fibrin result of < or = 1.35 micrograms/ml showed a sensitivity of 90.3% and a specificity of 49.4% for PE. The soluble fibrin assay has potential clinical utility in excluding PE.

  15. Effects of dextran on the molecular structure and tensile behaviour of human fibrin.

    PubMed

    Dhall, T Z; Bryce, W A; Dhall, D P

    1976-06-30

    Characteristic changes induced by dextran during the conversion of fibrinogen to fibrin have previously been shown to be associated with profound alterations in morphology of fibrin. However, whether dextran is incorporated into the fibrin molecule and whether morphological changes are associated with alterations in mechanical behaviour of formed fibrin was unclear. The investigations described show that the fibrin made in the presence of dextran has a shortened syneresis time, a lowered modulus of elasticity, an increased elongation and diminished ultimate strength at break. The molecular composition of fibrin clots remains unaltered despite the altered mechanical properties and morphological changes. Furthermore, dextran is not incorporated into the fibrin structure in any appreciable quantity. It is suggested that these several effects of dextran on clot morphology, tensile behaviour and kinetics of fibrin formation arise from increased forces of attraction between fibrin molecules such that fibrin chains are held together by weak secondary cross-links rather than by stronger primary cross-links which are hidden within the thicker fibrin chain bundles.

  16. Regulation of plasmin-dependent fibrin clot lysis by annexin II heterotetramer.

    PubMed

    Choi, K S; Fitzpatrick, S L; Filipenko, N R; Fogg, D K; Kassam, G; Magliocco, A M; Waisman, D M

    2001-07-01

    In a previous report we showed that plasmin-dependent lysis of a fibrin polymer, produced from purified components, was totally blocked if annexin II heterotetramer (AIIt) was present during fibrin polymer formation. Here, we show that AIIt inhibits fibrin clot lysis by stimulation of plasmin autodegradation, which results in a loss of plasmin activity. Furthermore, the C-terminal lysine residues of its p11 subunit play an essential role in the inhibition of fibrin clot lysis by AIIt. We also found that AIIt binds to fibrin with a K(d) of 436 nm and a stoichiometry of about 0.28 mol of AIIt/mol of fibrin monomer. The binding of AIIt to fibrin was not dependent on the C-terminal lysines of the p11 subunit. Furthermore, in the presence of plasminogen, the binding of AIIt to fibrin was increased to about 1.3 mol of AIIt/mol of fibrin monomer, suggesting that AIIt and plasminogen do not compete for identical sites on fibrin. Immunohistochemical identification of p36 and p11 subunits of AIIt in a pathological clot provides important evidence for its role as a physiological fibrinolytic regulator. These results suggest that AIIt may play a key role in the regulation of plasmin activity on the fibrin clot surface. PMID:11319229

  17. Discrimination between Fibrin and Fibrinogen by a Monoclonal Antibody against a Synthetic Peptide

    NASA Astrophysics Data System (ADS)

    Scheefers-Borchel, Ursula; Muller-Berghaus, Gert; Fuhge, Peter; Eberle, Reinhard; Heimburger, Nobert

    1985-10-01

    Circulating soluble fibrin, observed in the blood of patients with ongoing intravascular coagulation, is generated from the plasma protein fibrinogen by the limited proteolytic action of thrombin. We report the production of a monoclonal antibody that discriminates between fibrin and fibrinogen in blood. The synthetic hexapeptide Gly-Pro-Arg-Val-Val-Glu, representing the amino terminus of the α chain of human fibrin, was used as immunogen. This hexapeptide is located within the Aα chain of fibrinogen but becomes the amino terminus of the fibrin α chain, after fibrinopeptide A is removed by the action of thrombin, and thus becomes accessible for antibody binding. The monoclonal antibody we have prepared can discriminate between fibrin and fibrinogen and thus can be used in assay systems to quantitate soluble fibrin or, potentially, to image fibrin-rich thrombi.

  18. Fibrin deposited in the Alzheimer's disease brain promotes neuronal degeneration.

    PubMed

    Cortes-Canteli, Marta; Mattei, Larissa; Richards, Allison T; Norris, Erin H; Strickland, Sidney

    2015-02-01

    Alzheimer's disease (AD) is the most common form of dementia and has no effective treatment. Besides the well-known pathologic characteristics, this disease also has a vascular component, and substantial evidence shows increased thrombosis as well as a critical role for fibrin(ogen) in AD. This molecule has been implicated in neuroinflammation, neurovascular damage, blood-brain barrier permeability, vascular amyloid deposition, and memory deficits that are observed in AD. Here, we present evidence demonstrating that fibrin deposition increases in the AD brain and correlates with the degree of pathology. Moreover, we show that fibrin(ogen) is present in areas of dystrophic neurites and that a modest decrease in fibrinogen levels improves neuronal health and ameliorates amyloid pathology in the subiculum of AD mice. Our results further characterize the important role of fibrin(ogen) in this disease and support the design of therapeutic strategies aimed at blocking the interaction between fibrinogen and amyloid-β (Aβ) and/or normalizing the increased thrombosis present in AD. PMID:25475538

  19. Fibrin polymerization as a phase transition wave: A mathematical model

    NASA Astrophysics Data System (ADS)

    Lobanov, A. I.

    2016-06-01

    A mathematical model of fibrin polymerization is described. The problem of the propagation of phase transition wave is reduced to a nonlinear Stefan problem. A one-dimensional discontinuity fitting difference scheme is described, and the results of one-dimensional computations are presented.

  20. Investigating the interaction between acoustically stimulated microbubbles and fibrin clots

    NASA Astrophysics Data System (ADS)

    Acconcia, Christopher; Leung, Ben; Hynynen, Kullervo; Goertz, David

    2012-11-01

    While it is well established that ultrasound stimulated microbubbles can potentiate thrombolysis, the mechanisms of action are poorly understood. The objective of this work was to gain a more fundamental understanding of how acoustically stimulated microbubbles interact with and potentially degrade fibrin clots. Owing to their optical transparency, the use of fibrin clots allowed to optically observe microbubbles interacting with the clot boundary and any resultant disruption of the fluorescently tagged fibrin network. It was found that microbubbles could readily penetrate into fibrin clots with velocities up to 0.2 m/s and to depths related to the number of pulses applied. At lower pressures (0.2-0.55 MPa), microbubbles as small as 3μm were observed to penetrate, whereas higher pressures (>0.9 MPa) caused the penetration of larger microbubbles (10-30μm), formed by coalescence prior to entry. In some cases, patent 'tunnels' remained along the path taken by penetrating microbubbles. Tunnel diameters ranged between 9-35μm depending largely on pressure and pulse duration. Two-photon microscopy indicated either patent tunnels or paths of disrupted fibers consistent with collapsed tunnel. Fluid flow within the clot was observed to accompany penetrating microbubbles, which may have implications for lytic enzyme penetration.

  1. A Constitutive Model for a Maturing Fibrin Network

    PubMed Central

    van Kempen, Thomas H.S.; Bogaerds, Arjen C.B.; Peters, Gerrit W.M.; van de Vosse, Frans N.

    2014-01-01

    Blood clot formation is crucial to maintain normal physiological conditions but at the same time involved in many diseases. The mechanical properties of the blood clot are important for its functioning but complicated due to the many processes involved. The main structural component of the blood clot is fibrin, a fibrous network that forms within the blood clot, thereby increasing its mechanical rigidity. A constitutive model for the maturing fibrin network is developed that captures the evolving mechanical properties. The model describes the fibrin network as a network of fibers that become thicker in time. Model parameters are related to the structural properties of the network, being the fiber length, bending stiffness, and mass-length ratio. Results are compared with rheometry experiments in which the network maturation is followed in time for various loading frequencies and fibrinogen concentrations. Three parameters are used to capture the mechanical behavior including the mass-length ratio. This parameter agrees with values determined using turbidimetry experiments and is subsequently used to derive the number of protofibrils and fiber radius. The strength of the model is that it describes the mechanical properties of the maturing fibrin network based on it structural quantities. At the same time the model is relatively simple, which makes it suitable for advanced numerical simulations of blood clot formation during flow in blood vessels. PMID:25028892

  2. Extravascular fibrin, plasminogen activator, plasminogen activator inhibitors, and airway hyperresponsiveness

    PubMed Central

    Wagers, Scott S.; Norton, Ryan J.; Rinaldi, Lisa M.; Bates, Jason H.T.; Sobel, Burton E.; Irvin, Charles G.

    2004-01-01

    Mechanisms underlying airway hyperresponsiveness are not yet fully elucidated. One of the manifestations of airway inflammation is leakage of diverse plasma proteins into the airway lumen. They include fibrinogen and thrombin. Thrombin cleaves fibrinogen to form fibrin, a major component of thrombi. Fibrin inactivates surfactant. Surfactant on the airway surface maintains airway patency by lowering surface tension. In this study, immunohistochemically detected fibrin was seen along the luminal surface of distal airways in a patient who died of status asthmaticus and in mice with induced allergic airway inflammation. In addition, we observed altered airway fibrinolytic system protein balance consistent with promotion of fibrin deposition in mice with allergic airway inflammation. The airways of mice were exposed to aerosolized fibrinogen, thrombin, or to fibrinogen followed by thrombin. Only fibrinogen followed by thrombin resulted in airway hyperresponsiveness compared with controls. An aerosolized fibrinolytic agent, tissue-type plasminogen activator, significantly diminished airway hyperresponsiveness in mice with allergic airway inflammation. These results are consistent with the hypothesis that leakage of fibrinogen and thrombin and their accumulation on the airway surface can contribute to the pathogenesis of airway hyperresponsiveness. PMID:15232617

  3. Fiber optic immunosensor for cross-linked fibrin concentration

    NASA Astrophysics Data System (ADS)

    Moskowitz, Samuel E.

    2000-08-01

    Working with calcium ions in the blood, platelets produce thromboplastin which transforms prothrombin into thrombin. Removing peptides, thrombin changes fibrinogen into fibrin. Cross-linked insoluble fibrin polymers are solubilized by enzyme plasmin found in blood plasma. Resulting D-dimers are elevated in patients with intravascular coagulation, deep venous thrombosis, pulmonary embolism, myocardial infarction, multiple trauma, cancer, impaired renal and liver functions, and sepsis. Consisting principally of a NIR 780 nm GaAlAs laser diode and a 800 nm avalanche photodiode (APD), the fiber-optic immunosensor can determined D-dimer concentration to levels <0.1 ng/ml. A capture monoclonal antibody to the antigen soluble cross-linked fibrin is employed. Immobilized at the tip of an optical fiber by avidin-biotin, the captured antigen is detected by a second antibody which is labeled with NN 382 fluorescent dye. An evanescent wave traveling on an excitation optical fiber excites the antibody-antigen fluorophore complex. Concentration of cross-linked fibrin is directly proportional to the APD measured intensity of fluorescence. NIR fluorescence has advantages of low background interference, short fluorescence lifetime, and large difference between excitation and emission peaks. Competitive ELISA test for D-dimer concentration requires trained personnel performing a time consuming operation.

  4. The use of platelet-rich fibrin combined with periodontal ligament and jaw bone mesenchymal stem cell sheets for periodontal tissue engineering.

    PubMed

    Wang, Zhong-Shan; Feng, Zhi-Hong; Wu, Guo-Feng; Bai, Shi-Zhu; Dong, Yan; Chen, Fa-Ming; Zhao, Yi-Min

    2016-01-01

    Periodontal regeneration involves the restoration of at least three unique tissues: cementum, periodontal ligament tissue (PDL) and alveolar bone tissue. Here, we first isolated human PDL stem cells (PDLSCs) and jaw bone mesenchymal stem cells (JBMSCs). These cells were then induced to form cell sheets using an ascorbic acid-rich approach, and the cell sheet properties, including morphology, thickness and gene expression profile, were compared. Platelet-rich fibrin (PRF) derived from human venous blood was then fabricated into bioabsorbable fibrin scaffolds containing various growth factors. Finally, the in vivo potential of a cell-material construct based on PDLSC sheets, PRF scaffolds and JBMSC sheets to form periodontal tissue was assessed in a nude mouse model. In this model, PDLSC sheet/PRF/JBMSC sheet composites were placed in a simulated periodontal space comprising human treated dentin matrix (TDM) and hydroxyapatite (HA)/tricalcium phosphate (TCP) frameworks. Eight weeks after implantation, the PDLSC sheets tended to develop into PDL-like tissues, while the JBMSC sheets tended to produce predominantly bone-like tissues. In addition, the PDLSC sheet/PRF/JBMSC sheet composites generated periodontal tissue-like structures containing PDL- and bone-like tissues. Further improvements in this cell transplantation design may have the potential to provide an effective approach for future periodontal tissue regeneration. PMID:27324079

  5. The use of platelet-rich fibrin combined with periodontal ligament and jaw bone mesenchymal stem cell sheets for periodontal tissue engineering

    PubMed Central

    Wang, Zhong-Shan; Feng, Zhi-Hong; Wu, Guo-Feng; Bai, Shi-Zhu; Dong, Yan; Chen, Fa-Ming; Zhao, Yi-Min

    2016-01-01

    Periodontal regeneration involves the restoration of at least three unique tissues: cementum, periodontal ligament tissue (PDL) and alveolar bone tissue. Here, we first isolated human PDL stem cells (PDLSCs) and jaw bone mesenchymal stem cells (JBMSCs). These cells were then induced to form cell sheets using an ascorbic acid-rich approach, and the cell sheet properties, including morphology, thickness and gene expression profile, were compared. Platelet-rich fibrin (PRF) derived from human venous blood was then fabricated into bioabsorbable fibrin scaffolds containing various growth factors. Finally, the in vivo potential of a cell-material construct based on PDLSC sheets, PRF scaffolds and JBMSC sheets to form periodontal tissue was assessed in a nude mouse model. In this model, PDLSC sheet/PRF/JBMSC sheet composites were placed in a simulated periodontal space comprising human treated dentin matrix (TDM) and hydroxyapatite (HA)/tricalcium phosphate (TCP) frameworks. Eight weeks after implantation, the PDLSC sheets tended to develop into PDL-like tissues, while the JBMSC sheets tended to produce predominantly bone-like tissues. In addition, the PDLSC sheet/PRF/JBMSC sheet composites generated periodontal tissue-like structures containing PDL- and bone-like tissues. Further improvements in this cell transplantation design may have the potential to provide an effective approach for future periodontal tissue regeneration. PMID:27324079

  6. Capillary-Like Network Formation by Human Amniotic Fluid-Derived Stem Cells Within Fibrin/Poly(Ethylene Glycol) Hydrogels

    PubMed Central

    Benavides, Omar M.; Quinn, Joseph P.; Pok, Seokwon; Petsche Connell, Jennifer; Ruano, Rodrigo

    2015-01-01

    A major limitation in tissue engineering strategies for congenital birth defects is the inability to provide a significant source of oxygen, nutrient, and waste transport in an avascular scaffold. Successful vascularization requires a reliable method to generate vascular cells and a scaffold capable of supporting vessel formation. The broad potential for differentiation, high proliferation rates, and autologous availability for neonatal surgeries make amniotic fluid-derived stem cells (AFSC) well suited for regenerative medicine strategies. AFSC-derived endothelial cells (AFSC-EC) express key proteins and functional phenotypes associated with endothelial cells. Fibrin-based hydrogels were shown to stimulate AFSC-derived network formation in vitro but were limited by rapid degradation. Incorporation of poly(ethylene glycol) (PEG) provided mechanical stability (65%±9% weight retention vs. 0% for fibrin-only at day 14) while retaining key benefits of fibrin-based scaffolds—quick formation (10±3 s), biocompatibility (88%±5% viability), and vasculogenic stimulation. To determine the feasibility of AFSC-derived microvasculature, we compared AFSC-EC as a vascular cell source and AFSC as a perivascular cell source to established sources of these cell types—human umbilical vein endothelial cells (HUVEC) and mesenchymal stem cells (MSC), respectively. Cocultures were seeded at a 4:1 endothelial-to-perivascular cell ratio, and gels were incubated at 37°C for 2 weeks. Mechanical testing was performed using a stress-controlled rheometer (G′=95±10 Pa), and cell-seeded hydrogels were assessed based on morphology. Network formation was analyzed based on key parameters such as vessel thickness, length, and area, as well as the degree of branching. There was no statistical difference between individual cultures of AFSC-EC and HUVEC in regard to these parameters, suggesting the vasculogenic potential of AFSC-EC; however, the development of robust vessels required the

  7. Impact of homocysteine-thiolactone on plasma fibrin networks.

    PubMed

    Genoud, Valeria; Lauricella, Ana María; Kordich, Lucía C; Quintana, Irene

    2014-11-01

    Epidemiologic studies have shown that hyperhomocysteinemia is an independent risk factor for vascular disease. Homocysteine (Hcy) circulates as different species, mostly protein bound, and approximately 1% as its reduced form and the cyclic thioester homocysteine-thiolactone (HTL). Despite the level of plasma thiolactone being markedly low, detrimental effects are related to its high reactivity. HTL reacts with proteins by acylation of free basic amino groups; in particular, the epsilon-amino group of lysine residues forms adducts and induces structural and functional changes in plasma proteins. In order to assess the effects of HTL on plasma fibrin networks, a pool of normal plasma incubated with HTL (100, 500 and 1,000 μmol/L, respectively) was evaluated by global coagulation tests and fibrin formation kinetic assays, and the resulting fibrin was observed by scanning electron microscopy. HTL significantly prolonged global coagulation tests in a concentration-dependent manner with respect to control, and increases were up to 14.5%. Fibrin formation kinetic parameters displayed statistically significant differences between HTL-treated plasma and control in a concentration-dependent way, showing higher lag phase and lower maximum reaction velocity and final network optical density. Electron microscopy analysis of HTL plasma networks revealed a compact architecture, with more branches and shorter fibers than control. We can conclude that HTL induced a slower coagulation process, rendering more tightly packed fibrin clots. Since these features of the networks have been related to impaired fibrinolysis, the N-homocysteinylation reactions would be involved in the prothrombotic effects associated to hyperhomocysteinemia.

  8. Increased Plasminogen Activator (Urokinase) in Tissue Culture After Fibrin Deposition

    PubMed Central

    Bernik, Maria B.

    1973-01-01

    Lysis of fibrin in tissue culture has been shown to be due to plasminogen activator identified immunologically as urokinase. The present study examines fibrinolytic events in culture, particularly mechanisms leading to increased urokinase levels and accelerated fibrinolysis. Deposition of fibrin on cells in culture was followed by a two- to six-fold increase in urokinase in the supernates and rapid disappearance of the fibrin. Investigation of factors that might be responsible for these events (including fibrin, fibrinogen, vasoactive stimuli, and the enzymes thrombin and plasmin) indicated that the enhanced urokinase yields were mediated through plasmin and thrombin. Study of the possible modes of action of thrombin and plasmin indicated that these enzymes are capable of acting on the cells themselves as well as on cell-produced material. The effect on cells was manifested by mitotic activity or, occasionally, cell injury and death. Although these effects influenced urokinase levels, enhanced yields were explained best by the action of enzymes on cellproduced material. Studies with plasmin and thrombin, and also trypsin, indicated that proteolytic enzymes may act in various ways—affect the stability of urokinase, interfere with inhibition of urokinase by naturally occurring inhibitor(s), and induce urokinase activity from inactive material. Plasma and thrombin appeared to act primarily through the latter mechanism. Inactive material, which gave rise to urokinase upon exposure to proteolytic enzymes and which may represent urokinase precursor, was found in cultures of kidney, lung, spleen, and thyroid. Urokinase in such inactive state appears to be readily accessible to activation by enzymes, particularly plasmin and thrombin, thus facilitating removal of fibrin and possibly also providing pathways to excessive fibrinolysis. PMID:4266421

  9. Relative Gain Monitoring of the GlueX Calorimeters

    SciTech Connect

    Anassontzis, Efstratios G.; Kourkoumelis, C.; Vasileiadis, G.; Voulgaris, G.; Kappos, E.; Beattie, T.; Krueger, S.; Lolos, G. J.; Papandreou, Z.; Semenov, A. Yu.; Frye, John M.; Leckey, John P.; Shepherd, Matt; Bogart, T.; Smith, Elton S.

    2014-02-01

    The relative gain of the photodetectors for the GlueX Barrel and Forward calorimeters will be monitored using modular LED driver systems. The BCAL system consists of a global controller that feeds power, bias voltage and trigger signals to 96 local controllers situated at the ends of the 48 BCAL modules, which drive 40 LEDs associated with the 40 light guides at the end of each module. The FCAL system consists also of a global controller, a local controller for each acrylic quadrant covering the face of the FCAL, and ten 4-LED pulser boards per local controller connected in a star configuration along the edges of the acrylic panes. The respective systems are currently being installed on the detectors and their tested performance is presented herein.

  10. Glubran 2: A New Acrylic Glue for Neuroradiological Endovascular Use

    PubMed Central

    Leonardi, M.; Barbara, C.; Simonetti, L.; Giardino, R.; Nicoli Aldini, N.; Fini, M.; Martini, L.; Masetti, L.; Joechler, M.; Roncaroli, F.

    2002-01-01

    Summary A new acrylic glue, Glubran 2, is now available on the European market. It bears the CE mark with several surgical indications and the specific indication for neuroradiological endovascular use. Despite this approval, to our knowledge its use is still limited to surgery and no injections have been made in human patients. This study was designed to evaluate the behavior of Glubran 2 in endovascular injection in a simulation of brain AVM. Six sheep were operated on opening a fistula between the right common carotid artery and the jugular vein. This fistula modifies blood flow in the skull base rete mirabilis, which then functions as an AVM. In two sheep, the rete mirabilis was occluded by injection of 1.5 ml of Histoacryl diluted 1:1 and 1:3 with Lipiodol. In two sheep, the rete was embolized by injection of 1.5 ml of Glubran 2 diluted 1:1 with Lipiodol. The last two sheep were embolized by injection of Glubran 2 diluted 1:3 with Lipiodol. The procedures were documented by DSA angiographic acquisitions and by fluoroscopic VHS. The sheep were killed immediately after the procedures and the rete mirabilis isolated for histologic examination. Embolization was obtained with both kinds of glue. Glubran 2 diffuses in a very similar way to Histoacryl with an apparently more complete diffusion. Reflux in the ascending pharyngeal artery showed that Glubran 2 tended not to produce bubbles but diffused more homogeneously. The subjective conclusion of this work is that Glubran 2 can be used in endovascular embolizations. Before approaching brain AVMs, a further study will investigate embolization of the external carotid territory. PMID:20594482

  11. Elastic Behavior and Platelet Retraction in Low- and High-Density Fibrin Gels

    PubMed Central

    Wufsus, Adam R.; Rana, Kuldeepsinh; Brown, Andrea; Dorgan, John R.; Liberatore, Matthew W.; Neeves, Keith B.

    2015-01-01

    Fibrin is a biopolymer that gives thrombi the mechanical strength to withstand the forces imparted on them by blood flow. Importantly, fibrin is highly extensible, but strain hardens at low deformation rates. The density of fibrin in clots, especially arterial clots, is higher than that in gels made at plasma concentrations of fibrinogen (3–10 mg/mL), where most rheology studies have been conducted. Our objective in this study was to measure and characterize the elastic regimes of low (3–10 mg/mL) and high (30–100 mg/mL) density fibrin gels using shear and extensional rheology. Confocal microscopy of the gels shows that fiber density increases with fibrinogen concentration. At low strains, fibrin gels act as thermal networks independent of fibrinogen concentration. Within the low-strain regime, one can predict the mesh size of fibrin gels by the elastic modulus using semiflexible polymer theory. Significantly, this provides a link between gel mechanics and interstitial fluid flow. At moderate strains, we find that low-density fibrin gels act as nonaffine mechanical networks and transition to affine mechanical networks with increasing strains within the moderate regime, whereas high-density fibrin gels only act as affine mechanical networks. At high strains, the backbone of individual fibrin fibers stretches for all fibrin gels. Platelets can retract low-density gels by >80% of their initial volumes, but retraction is attenuated in high-density fibrin gels and with decreasing platelet density. Taken together, these results show that the nature of fibrin deformation is a strong function of fibrin fiber density, which has ramifications for the growth, embolization, and lysis of thrombi. PMID:25564864

  12. Specific identification of fibrin polymers, fibrinogen degradation products, and crosslinked fibrin degradation products in plasma and serum with a new sensitive technique.

    PubMed

    Connaghan, D G; Francis, C W; Lane, D A; Marder, V J

    1985-03-01

    A new method is described for identifying low concentrations of circulating derivatives of fibrinogen and fibrin, even when present in heterogeneous mixtures. This technique is applicable to plasma and serum and uses electrophoresis in 2% agarose in the presence of sodium dodecyl sulfate (SDS) followed by immunological identification of separated derivatives, using radiolabeled antifibrinogen antiserum and autoradiography. Unique electrophoretic patterns distinguish plasmic derivatives of crosslinked fibrin from those of fibrinogen and also identify crosslinked fibrin polymers produced by the combined action of thrombin and factor XIII on fibrinogen. The assay is sensitive to a concentration of 0.1 micrograms/mL of fibrinogen in serum or plasma. Fibrin polymers, plasmic degradation products of fibrinogen, and plasmic degradation products of crosslinked fibrin were detected in the plasma or serum of a patient with disseminated intravascular coagulation. Plasmic derivatives of both fibrinogen and crosslinked fibrin appeared in serum in the course of fibrinolytic therapy for pulmonary embolism, whereas during acute myocardial infarction a marked increase in the proportion of fibrin polymers in plasma was found in comparison with normal controls. Thus, the procedure can distinguish between the simultaneous processes of fibrin polymer formation, fibrinogenolysis, and fibrinolysis, and is sufficiently sensitive to detect relevant quantities of derivatives in pathologic conditions.

  13. Study the bonding mechanism of binders on hydroxyapatite surface and mechanical properties for 3DP fabrication bone scaffolds.

    PubMed

    Wei, Qinghua; Wang, Yanen; Li, Xinpei; Yang, Mingming; Chai, Weihong; Wang, Kai; zhang, Yingfeng

    2016-04-01

    In 3DP fabricating artificial bone scaffolds process, the interaction mechanism between binder and bioceramics power determines the microstructure and macro mechanical properties of Hydroxyapatite (HA) bone scaffold. In this study, we applied Molecular Dynamics (MD) methods to investigating the bonding mechanism and essence of binders on the HA crystallographic planes for 3DP fabrication bone scaffolds. The cohesive energy densities of binders and the binding energies, PCFs g(r), mechanical properties of binder/HA interaction models were analyzed through the MD simulation. Additionally, we prepared the HA bone scaffold specimens with different glues by 3DP additive manufacturing, and tested their mechanical properties by the electronic universal testing machine. The simulation results revealed that the relationship of the binding energies between binders and HA surface is consistent with the cohesive energy densities of binders, which is PAM/HA>PVA/HA>PVP/HA. The PCFs g(r) indicated that their interfacial interactions mainly attribute to the ionic bonds and hydrogen bonds which formed between the polar atoms, functional groups in binder polymer and the Ca, -OH in HA. The results of mechanical experiments verified the relationship of Young׳s modulus for three interaction models in simulation, which is PVA/HA>PAM/HA>PVP/HA. But the trend of compressive strength is PAM/HA>PVA/HA>PVP/HA, this is consistent with the binding energies of simulation. Therefore, the Young׳s modulus of bone scaffolds are limited by the Young׳s modulus of binders, and the compressive strength is mainly decided by the viscosity of binder. Finally, the major reasons for differences in mechanical properties between simulation and experiment were found, the space among HA pellets and the incomplete infiltration of glue were the main reasons influencing the mechanical properties of 3DP fabrication HA bone scaffolds. These results provide useful information in choosing binder for 3DP fabrication

  14. [Comparison of optimum, RSA and GLUE methods in parameter identification of a nonlinear environmental model].

    PubMed

    Deng, Yixiang; Wang, Qi; Lai, Siyun; Chen, Jining

    2003-11-01

    Parameter identification plays a key role in environmental model application. The optimization method is one of the earliest and most widely used methods. However, as the parameters by optimization may not fully fit the observations, there is a risk that the errors may be enhanced in the decision-make stage. With this deficiency in consideration, the RSA and GLUE algorithms search for the feasible parameters not only to the optimum but also around the neighbors. The difference between RSA and GLUE is that the RSA accepts the estimated parameters equally as the candidates for application; while the GLUE keeps the difference among the parameters as measured by likelihood. In addition for parameter identification, both RSA and GLUE are efficient tools for global sensitivity analysis.

  15. Nonlinear temperature dependence of glue-induced birefringence in polarization maintaining FBG sensors

    NASA Astrophysics Data System (ADS)

    Hopf, Barbara; Koch, Alexander W.; Roths, Johannes

    2016-05-01

    Glue-induced stresses decrease the accuracy of surface-mounted fiber Bragg gratings (FBG). Significant temperature dependent glue-induced birefringence was verified when a thermally cured epoxy-based bonding technique had been used. Determining the peak separation of two azimuthally aligned FBGs in PM fibers combined with a polarization resolved measurement set-up in a temperature range between -30°C and 150°C revealed high glue-induced stresses at low temperatures. Peak separations of about 60 pm and a nonlinear temperature dependence of the glue-induced birefringence due to stress relaxation processes and a visco-elastic behavior of the used adhesive have been shown.

  16. Potential of nanocrystalline cellulose-fibrin nanocomposites for artificial vascular graft applications

    SciTech Connect

    Brown, Elvie; Hu, Dehong; Abu-Lail, Nehal; Zhang, Xiao

    2013-02-19

    Nanocrystalline cellulose, a new bio-nanomaterial is utilized as a reinforcing material for biocompatible fibrin matrix to form into a nanocomposite for small-diameter replacement vascular graft application (SDRVG). The periodate oxidation of NCC, which provided it with a reactive carbonyl group, allowed molecular interaction between NCC and fibrin. Such interaction resulted into an effective mechanical reinforcement indicated by the improvement of max. force, elongation at break and modulus when oxidized NCC (ONCC) was incorporated into fibrin. The nanocomposite’s mechanical properties can be manipulated to conform to the native blood vessel by varying the ONCC to fibrin ratio and/or by controlling the degree of oxidation of NCC. Using atomic force microscopy had provided fundamental information on the effects of molecular interactions to the nanolevel mechanical properties of NCC/fibrin nanocomposites. This fundamental information established the positive feasibility and commenced continuing investigation for the practical SDRVG application of NCC/fibrin nanocomposite.

  17. Interaction of Fibrin with the VLDL Receptor: Further Characterization and Localization of the Fibrin-Binding Site

    PubMed Central

    Yakovlev, Sergiy; Medved, Leonid

    2016-01-01

    Our recent study revealed that fibrin interacts with the VLDL receptor (VLDLR) on endothelial cells through its βN-domains and this interaction promotes transendothelial migration of leukocytes and thereby inflammation. The major aims of the present study were to further characterize this interaction and localize fibrin-binding site in the VLDL receptor. To localize the fibrin-binding site, we expressed a soluble extracellular portion of this receptor, sVLDLRHT, its N- and C-terminal regions, VLDLR(1–8)HT and des(1–8)VLDLRHT, respectively, and a number of VLDLR fragments containing various combinations of CR-domains, and confirmed their proper folding by fluorescence spectroscopy. Interaction of these fragments with the (β15–66)2 fragment corresponding to a pair of VLDLR-binding βN-domains of fibrin was tested by different methods. Our experiments performed by ELISA and surface plasmon resonance revealed that the VLDLR(1–8)HT fragment containing eight CR-domain of VLDLR and its sub-fragments, VLDLR(1–4)HT and VLDLR(2–4)HT, interact with (β15–66)2 with practically the same affinity as sVLDLRHT while the affinity of VLDLR(2–3)HT was about 2-fold lower. In contrast, des(1–8)VLDLRHT exhibited no binding. Complex formation in solution between the fibrin-binding fragments of VLDLR and (β15–66)2 was detected by fluorescence spectroscopy. In addition, formation of a complex between VLDLR(2–4)HT and (β15–66)2 in solution was confirmed by size-exclusion chromatography. Thus, the results obtained indicate that minimal fibrin-binding structures are located within the second and third CR-domains of the VLDL receptor and the presence of the fourth CR-domain is required for the high affinity binding. They also indicate that tryptophan residues of CR-domains are involved in this binding. PMID:26153297

  18. Double Coaxial Microcatheter Technique for Glue Embolization of Renal Arteriovenous Malformations

    SciTech Connect

    Uchikawa, Yoko; Mori, Kensaku; Shiigai, Masanari; Konishi, Takahiro; Hoshiai, Sodai; Ishigro, Toshitaka Hiyama, Takashi; Nakai, Yasunobu; Minami, Manabu

    2015-10-15

    PurposeTo demonstrate the technical benefit of the double coaxial microcatheter technique for embolization of renal arteriovenous malformations (AVMs) with n-butyl cyanoacrylate and iodized oil (glue).Materials and MethodsSix consecutive patients (1 man and 5 women; mean age 61 years; range 44–77 years) with renal AVMs were included. Five patients had hematuria, and one had a risk of heart failure due to a large intrarenal arteriovenous shunt. All patients underwent transarterial embolization using glue and the double coaxial microcatheter technique with outer 2.6F and inner 1.9F microcatheters. After glue injection, the inner microcatheter was retracted, while the outer microcatheter was retained. We assessed the complications and clinical outcomes of this technique.ResultsTechnical success was achieved in all patients. In 9 sessions, 34 feeding arteries were embolized with glue using the double coaxial microcatheter technique, 1 was embolized with glue using a single microcatheter, and 2 were embolized with coils. The double coaxial microcatheter technique was useful for selecting small tortuous feeding arteries, preventing glue reflux to the proximal arteries, and approaching multiple feeding arteries without complete retraction of the microcatheters. As a minor complication, glue migrated into the venous system in four patients without any sequelae. In all patients, favorable clinical outcomes, including hematuria cessation in five patients and improvement of the large intrarenal arteriovenous shunt in one patient, were obtained without deterioration of renal function.ConclusionGlue embolization with the double coaxial microcatheter technique was useful for treating renal AVMs with multiple tortuous feeding arteries.

  19. Chondrogenic regeneration using bone marrow clots and a porous polycaprolactone-hydroxyapatite scaffold by three-dimensional printing.

    PubMed

    Yao, Qingqiang; Wei, Bo; Liu, Nancy; Li, Chenshuang; Guo, Yang; Shamie, Arya Nick; Chen, James; Tang, Cheng; Jin, Chengzhe; Xu, Yan; Bian, Xiuwu; Zhang, Xinli; Wang, Liming

    2015-04-01

    Scaffolds play an important role in directing three-dimensional (3D) cartilage regeneration. Our recent study reported the potential advantages of bone marrow clots (MC) in promoting extracellular matrix (ECM) scaffold chondrogenic regeneration. The aim of this study is to build a new scaffold for MC, with improved characteristics in mechanics, shaping, and biodegradability, compared to our previous study. To address this issue, this study prepared a 3D porous polycaprolactone (PCL)-hydroxyapatite (HA) scaffold combined with MC (Group A), while the control group (Group B) utilized a bone marrow stem cell seeded PCL-HA scaffold. The results of in vitro cultures and in vivo implantation demonstrated that although an initial obstruction of nutrient exchange caused by large amounts of fibrin and erythrocytes led to a decrease in the ratio of live cells in Group A, these scaffolds also showed significant improvements in cell adhesion, proliferation, and chondrogenic differentiation with porous recanalization in the later culture, compared to Group B. After 4 weeks of in vivo implantation, Group A scaffolds have a superior performance in DNA content, Sox9 and RunX2 expression, cartilage lacuna-like cell and ECM accumulation, when compared to Group B. Furthermore, Group A scaffold size and mechanics were stable during in vitro and in vivo experiments, unlike the scaffolds in our previous study. Our results suggest that the combination with MC proved to be a highly efficient, reliable, and simple new method that improves the biological performance of 3D PCL-HA scaffold. The MC-PCL-HA scaffold is a candidate for future cartilage regeneration studies.

  20. Chondrogenic Regeneration Using Bone Marrow Clots and a Porous Polycaprolactone-Hydroxyapatite Scaffold by Three-Dimensional Printing

    PubMed Central

    Yao, Qingqiang; Wei, Bo; Liu, Nancy; Li, Chenshuang; Guo, Yang; Shamie, Arya Nick; Chen, James; Tang, Cheng; Jin, Chengzhe; Xu, Yan

    2015-01-01

    Scaffolds play an important role in directing three-dimensional (3D) cartilage regeneration. Our recent study reported the potential advantages of bone marrow clots (MC) in promoting extracellular matrix (ECM) scaffold chondrogenic regeneration. The aim of this study is to build a new scaffold for MC, with improved characteristics in mechanics, shaping, and biodegradability, compared to our previous study. To address this issue, this study prepared a 3D porous polycaprolactone (PCL)-hydroxyapatite (HA) scaffold combined with MC (Group A), while the control group (Group B) utilized a bone marrow stem cell seeded PCL-HA scaffold. The results of in vitro cultures and in vivo implantation demonstrated that although an initial obstruction of nutrient exchange caused by large amounts of fibrin and erythrocytes led to a decrease in the ratio of live cells in Group A, these scaffolds also showed significant improvements in cell adhesion, proliferation, and chondrogenic differentiation with porous recanalization in the later culture, compared to Group B. After 4 weeks of in vivo implantation, Group A scaffolds have a superior performance in DNA content, Sox9 and RunX2 expression, cartilage lacuna-like cell and ECM accumulation, when compared to Group B. Furthermore, Group A scaffold size and mechanics were stable during in vitro and in vivo experiments, unlike the scaffolds in our previous study. Our results suggest that the combination with MC proved to be a highly efficient, reliable, and simple new method that improves the biological performance of 3D PCL-HA scaffold. The MC-PCL-HA scaffold is a candidate for future cartilage regeneration studies. PMID:25530453

  1. Platelet-rich fibrin matrix for facial plastic surgery.

    PubMed

    Sclafani, Anthony P; Saman, Masoud

    2012-05-01

    Platelets are known primarily for their role in hemostasis, but there is increasing interest in the effect of platelets on wound healing. Platelet isolates such as platelet-rich plasma have been advocated to enhance and accelerate wound healing. This article describes the use of a novel preparation, platelet-rich fibrin matrix (PRFM), for facial plastic surgery applications such as volume augmentation, fat transfer supplementation, and as an adjunct to open surgical procedures.

  2. Altered plasma fibrin clot properties in essential thrombocythemia.

    PubMed

    Małecki, Rafał; Gacka, Małgorzata; Kuliszkiewicz-Janus, Małgorzata; Jakobsche-Policht, Urszula; Kwiatkowski, Jacek; Adamiec, Rajmund; Undas, Anetta

    2016-01-01

    Patients with increased thromboembolic risk tend to form denser fibrin clots which are relatively resistant to lysis. We sought to investigate whether essential thrombocythemia (ET) is associated with altered fibrin clot properties in plasma. Ex vivo plasma fibrin clot permeability coefficient (Ks), turbidimetry and clot lysis time (CLT) were measured in 43 consecutive patients with ET (platelet count from 245 to 991 × 10(3)/µL) and 50 control subjects matched for age, sex and comorbidities. Fibrinolysis proteins and inhibitors together with platelet activation markers were determined. Reduced Ks (-38%, p < 0.0001) and prolonged CLT (+34%, p < 0.0001) were observed in ET. The differences remained significant after adjustment for fibrinogen and platelet count. ET was associated with a slightly shorter lag phase (-5%, p = 0.01) and higher maximum absorbency of the turbidimetric curve (+6%, p < 0.001). The ET patients had higher plasma P-selectin by 193% (p < 0.00001) and platelet factor 4 (PF4) by 173% (p < 0.00001), with higher P-selectin observed in 19 (44%) patients with JAK-2 gene V617F mutation. Higher t-PA (+20%, p < 0.001), 23% higher plasminogen activator inhibitor-1, PAI-1 (+23%, p < 0.01) and unaltered thrombin-activatable fibrinolysis inhibitor, plasminogen and α2-antiplasmin activity were found in the ET group. Ks inversely correlated with fibrinogen, PF4 and C-reactive protein. CLT positively correlated only with PAI-1. Patients with ET display prothrombotic plasma fibrin clot phenotype including impaired fibrinolysis, which represents a new prothrombotic mechanism in this disease. PMID:25989112

  3. Effect of Glue Layers on Response of Cellulose Fiberboard at Low Temperature

    SciTech Connect

    Smith, A.C.

    2001-03-07

    Studies of crush performance of cane fiberboard assemblies, sometimes used in overpacks for radioactive materials packages, has shown that, under low temperature or desiccated conditions, a short duration transient stress spike may occur for specimens loaded parallel to the plane of the fiberboard. This effect has been attributed to the stiffening effect of the layers of glue bonding the fiberboard sheets together. The question of the possibility of a property of the fiberboard itself being responsible for this phenomenon has been raised. To answer this question, specimens of fiberboard were bonded with varying amounts of glue and the resulting joint evaluated. Microscopic analysis was performed of the Celotex(R) and glue layer in these specimens and in specimens cut from production packages. Available test results indicate that the Celotex(R) is essentially isotropic. No indication of cellulose properties which could account for the spike phenomenon was found. The study revealed that the glue layer is in the form of islands of glue, formed in pores on the fiberboard surface, connected by thin ligaments of glue.

  4. Evidence from Multiple Species that Spider Silk Glue Component ASG2 is a Spidroin

    PubMed Central

    Collin, Matthew A.; Clarke, Thomas H.; Ayoub, Nadia A.; Hayashi, Cheryl Y.

    2016-01-01

    Spiders in the superfamily Araneoidea produce viscous glue from aggregate silk glands. Aggregate glue coats prey-capture threads and hampers the escape of prey from webs, thereby increasing the foraging success of spiders. cDNAs for Aggregate Spider Glue 1 (ASG1) and 2 (ASG2) have been previously described from the golden orb-weaver, Nephila clavipes, and Western black widow, Latrodectus hesperus. To further investigate aggregate glues, we assembled ASG1 and ASG2 from genomic target capture libraries constructed from three species of cob-web weavers and three species of orb-web weavers, all araneoids. We show that ASG1 is unlikely to be a glue, but rather is part of a widespread arthropod gene family, the peritrophic matrix proteins. For ASG2, we demonstrate its remarkable architectural and sequence similarities to spider silk fibroins, indicating that ASG2 is a member of the spidroin gene family. Thus, spidroins have diversified into glues in addition to task-specific, high performance fibers. PMID:26875681

  5. Spider web glue: two proteins expressed from opposite strands of the same DNA sequence.

    PubMed

    Choresh, Omer; Bayarmagnai, Battuya; Lewis, Randolph V

    2009-10-12

    The various silks that make up the web of the orb web spiders have been studied extensively. However, success in prey capture depends as much on the web glue as on the fibers. Spider silk glue, which is considered one of the strongest and most effective biological glues, is an aqueous solution secreted from the orb weaving spider's aggregate glands and coats the spiral prey capturing threads of their webs. Studies identified the major component of the glue as microscopic nodules made of a glycoprotein. This study describes two newly discovered proteins that form the glue-glycoprotein of the golden orb weaving spider Nephila clavipes . Our results demonstrate that both proteins contain unique 110 amino acid repetitive domains that are encoded by opposite strands of the same DNA sequence. Thus, the genome of the spider encodes two distinct yet functionally related genes by using both strands of an identical DNA sequence. Moreover, the closest match for the nonrepetitive region of one of the proteins is chitin binding proteins. The web glue appears to have evolved a substantial level of sophistication matching that of the spider silk fibers.

  6. Dynamics of spider glue adhesion: effect of surface energy and contact area

    NASA Astrophysics Data System (ADS)

    Amarpuri, Gaurav; Chen, Yizhou; Blackledge, Todd; Dhinojwala, Ali

    Spider glue is a unique biological adhesive which is humidity responsive such that the adhesion continues to increase upto 100% relative humidity (RH) for some species. This is unlike synthetic adhesives that significantly drop in adhesion with an increase in humidity. However, most of adhesion data reported in literature have used clean hydrophilic glass substrate, unlike the hydrophobic, and charged insect cuticle surface that adheres to spider glue in nature. Previously, we have reported that the spider glue viscosity changes over five orders of magnitude with humidity. Here, we vary the surface energy and surface charge of the substrate to test the change in Larnioides cornutus spider glue adhesion with humidity. We find that an increase in both surface energy and surface charge density increases the droplet spreading and there exists an optimum droplet contact area where adhesion is maximized. Moreover, spider glue droplets act as reusable adhesive for low energy hydrophobic surface at the optimum humidity. These results explain why certain prey are caught more efficiently by spiders in their habitat. The mechanism by which spider species tune its glue adhesion for local prey capture can inspire new generation smart adhesives.

  7. Evidence from Multiple Species that Spider Silk Glue Component ASG2 is a Spidroin.

    PubMed

    Collin, Matthew A; Clarke, Thomas H; Ayoub, Nadia A; Hayashi, Cheryl Y

    2016-01-01

    Spiders in the superfamily Araneoidea produce viscous glue from aggregate silk glands. Aggregate glue coats prey-capture threads and hampers the escape of prey from webs, thereby increasing the foraging success of spiders. cDNAs for Aggregate Spider Glue 1 (ASG1) and 2 (ASG2) have been previously described from the golden orb-weaver, Nephila clavipes, and Western black widow, Latrodectus hesperus. To further investigate aggregate glues, we assembled ASG1 and ASG2 from genomic target capture libraries constructed from three species of cob-web weavers and three species of orb-web weavers, all araneoids. We show that ASG1 is unlikely to be a glue, but rather is part of a widespread arthropod gene family, the peritrophic matrix proteins. For ASG2, we demonstrate its remarkable architectural and sequence similarities to spider silk fibroins, indicating that ASG2 is a member of the spidroin gene family. Thus, spidroins have diversified into glues in addition to task-specific, high performance fibers.

  8. The potential applications of fibrin-coated electrospun polylactide nanofibers in skin tissue engineering.

    PubMed

    Bacakova, Marketa; Musilkova, Jana; Riedel, Tomas; Stranska, Denisa; Brynda, Eduard; Zaloudkova, Margit; Bacakova, Lucie

    2016-01-01

    Fibrin plays an important role during wound healing and skin regeneration. It is often applied in clinical practice for treatment of skin injuries or as a component of skin substitutes. We prepared electrospun nanofibrous membranes made from poly(l-lactide) modified with a thin fibrin nanocoating. Fibrin surrounded the individual fibers in the membrane and also formed a thin fibrous mesh on several places on the membrane surface. The cell-free fibrin nanocoating remained stable in the cell culture medium for 14 days and did not change its morphology. On membranes populated with human dermal fibroblasts, the rate of fibrin degradation correlated with the degree of cell proliferation. The cell spreading, mitochondrial activity, and cell population density were significantly higher on membranes coated with fibrin than on nonmodified membranes, and this cell performance was further improved by the addition of ascorbic acid in the cell culture medium. Similarly, fibrin stimulated the expression and synthesis of collagen I in human dermal fibroblasts, and this effect was further enhanced by ascorbic acid. The expression of beta1-integrins was also improved by fibrin, and on pure polylactide membranes, it was slightly enhanced by ascorbic acid. In addition, ascorbic acid promoted deposition of collagen I in the form of a fibrous extracellular matrix. Thus, the combination of nanofibrous membranes with a fibrin nanocoating and ascorbic acid seems to be particularly advantageous for skin tissue engineering. PMID:26955273

  9. Optical imaging of fibrin deposition to elucidate participation of mast cells in foreign body responses

    PubMed Central

    Weng, Hong; Tang, Ewin N.; Baker, David W.; Tang, Liping

    2014-01-01

    Mast cell activation has been shown to be an initiator and a key determinant of foreign body reactions. However, there is no non-invasive method that can quantify the degree of implant-associated mast cell activation. Taking advantage of the fact that fibrin deposition is a hallmark of mast cell activation around biomaterial implants, a near infrared probe was fabricated to have high affinity to fibrin. Subsequent in vitro testing confirmed that this probe has high affinity to fibrin. Using a subcutaneous particle implantation model, we found significant accumulation of fibrin-affinity probes at the implant sites as early as 15 min following particle implantation. The accumulation of fibrin-affinity probes at the implantation sites could also be substantially reduced if anti-coagulant – heparin was administered at the implant sites. Further studies have shown that subcutaneous administration of mast cell activator – compound 48/80 – prompted the accumulation of fibrin-affinity probes. However, implant-associated fibrin-affinity probe accumulation was substantially reduced in mice with mast cell deficiency. The results show that our fibrin-affinity probes may serve as a powerful tool to monitor and measure the extent of biomaterial-mediated fibrin deposition and mast cell activation in vivo. PMID:24342726

  10. The potential applications of fibrin-coated electrospun polylactide nanofibers in skin tissue engineering

    PubMed Central

    Bacakova, Marketa; Musilkova, Jana; Riedel, Tomas; Stranska, Denisa; Brynda, Eduard; Zaloudkova, Margit; Bacakova, Lucie

    2016-01-01

    Fibrin plays an important role during wound healing and skin regeneration. It is often applied in clinical practice for treatment of skin injuries or as a component of skin substitutes. We prepared electrospun nanofibrous membranes made from poly(l-lactide) modified with a thin fibrin nanocoating. Fibrin surrounded the individual fibers in the membrane and also formed a thin fibrous mesh on several places on the membrane surface. The cell-free fibrin nanocoating remained stable in the cell culture medium for 14 days and did not change its morphology. On membranes populated with human dermal fibroblasts, the rate of fibrin degradation correlated with the degree of cell proliferation. The cell spreading, mitochondrial activity, and cell population density were significantly higher on membranes coated with fibrin than on nonmodified membranes, and this cell performance was further improved by the addition of ascorbic acid in the cell culture medium. Similarly, fibrin stimulated the expression and synthesis of collagen I in human dermal fibroblasts, and this effect was further enhanced by ascorbic acid. The expression of beta1-integrins was also improved by fibrin, and on pure polylactide membranes, it was slightly enhanced by ascorbic acid. In addition, ascorbic acid promoted deposition of collagen I in the form of a fibrous extracellular matrix. Thus, the combination of nanofibrous membranes with a fibrin nanocoating and ascorbic acid seems to be particularly advantageous for skin tissue engineering. PMID:26955273

  11. The effects of immunosuppression and anticoagulation on fibrin deposition and swelling in rat cardiac allografts.

    PubMed

    Christmas, S E; Jasani, M K; Jayson, M I

    1987-01-01

    Rat cardiac allograft recipients were injected with radiolabeled human fibrinogen at intervals after transplantation. There was a progressive increase in tracer accumulation within graft ventricles, peaking at the time of rejection at about 30-fold that within syngeneic grafts. Protein extraction experiments indicated that ca. 90% of tracer was present as cross-linked fibrin at the time of rejection. Exudation within rejecting allografts was nearly threefold that in syngeneic grafts. The weight of allografts at different times after transplantation increased in close concordance with fibrin deposition. Pharmacologically immunosuppressed recipients showed negligible fibrin deposition and swelling whereas "B" rats and thoracic-duct-lymph-drained recipients showed moderate allograft swelling in the absence of significant fibrin deposition or rejection. The decreased fibrin deposition was not a result of depressed plasma clotting factor levels. B rats reconstituted with thoracic duct lymphocytes still had reduced allograft fibrin deposition in the presence of normal amounts of swelling and exudation. The anticoagulants warfarin and heparin greatly decreased allograft fibrin but were almost without effect on allograft swelling, exudation, and rejection. The possible participation of infiltrating macrophages in allograft fibrin deposition is discussed. Unlike cutaneous delayed hypersensitivity reactions, normal amounts of fibrin deposition appear not to be essential for full cardiac allograft rejection.

  12. Fibrin gel-immobilized primary osteoblasts in calcium phosphate bone cement: in vivo evaluation with regard to application as injectable biological bone substitute.

    PubMed

    Kneser, U; Voogd, A; Ohnolz, J; Buettner, O; Stangenberg, L; Zhang, Y H; Stark, G B; Schaefer, D J

    2005-01-01

    Osteogenic injectable bone substitutes may be useful for many applications. We developed a novel injectable bone substitute based on osteoblast-fibrin glue suspension and calcium phosphate bone cement (BC). Human osteoblasts were isolated from trabecular bone samples and cultured under standard conditions. Osteoblasts were suspended in fibrinogen solution (FS). BC was cured with thrombin solution. 8 x 4 mm injectable bone discs were prepared using silicon molds and a custom-made applicator device. Discs containing BC, BC/FS, or BC/FS/osteoblasts were implanted subcutaneously into athymic nude mice. After 3, 9 and 24 weeks, specimens were explanted and subjected to morphologic and biomechanical evaluation. In vitro fibrin gel-embedded osteoblasts displayed a differentiated phenotype as evidenced by alkaline phosphatase, collagen type 1 and von Kossa stains. A proportion of osteoblasts appeared morphologically intact over a 3-day in vitro period following application into the BC. BC/FS and BC/FS/osteoblast discs were sparsely infiltrated with vascularized connective tissue. There was no bone formation in implants from all groups. However, positive von Kossa staining only in BC/FS/osteoblast groups suggests engraftment of at least some of the transplanted cells. Biomechanical evaluation demonstrated initial stability of the composites. Young's modulus and maximal load did not differ significantly in the BC/FS and BC/FS/osteoblast groups. The practicability of osteoblast-containing injectable bone could be demonstrated. The dense microstructure and the suboptimal initial vascularization of the composites may explain the lack of bone formation. Modifications with regard to enhanced osteoblast survival are mandatory for a possible application as injectable osteogenic bone replacement system. PMID:16046862

  13. Exact approaches for scaffolding

    PubMed Central

    2015-01-01

    This paper presents new structural and algorithmic results around the scaffolding problem, which occurs prominently in next generation sequencing. The problem can be formalized as an optimization problem on a special graph, the "scaffold graph". We prove that the problem is polynomial if this graph is a tree by providing a dynamic programming algorithm for this case. This algorithm serves as a basis to deduce an exact algorithm for general graphs using a tree decomposition of the input. We explore other structural parameters, proving a linear-size problem kernel with respect to the size of a feedback-edge set on a restricted version of Scaffolding. Finally, we examine some parameters of scaffold graphs, which are based on real-world genomes, revealing that the feedback edge set is significantly smaller than the input size. PMID:26451725

  14. Acoustic droplet-hydrogel composites for spatial and temporal control of growth factor delivery and scaffold stiffness.

    PubMed

    Fabiilli, Mario L; Wilson, Christopher G; Padilla, Frédéric; Martín-Saavedra, Francisco M; Fowlkes, J Brian; Franceschi, Renny T

    2013-07-01

    Wound healing is regulated by temporally and spatially restricted patterns of growth factor signaling, but there are few delivery vehicles capable of the "on-demand" release necessary for recapitulating these patterns. Recently we described a perfluorocarbon double emulsion that selectively releases a protein payload upon exposure to ultrasound through a process known as acoustic droplet vaporization (ADV). In this study, we describe a delivery system composed of fibrin hydrogels doped with growth factor-loaded double emulsion for applications in tissue regeneration. Release of immunoreactive basic fibroblast growth factor (bFGF) from the composites increased up to 5-fold following ADV and delayed release was achieved by delaying exposure to ultrasound. Releasates of ultrasound-treated materials significantly increased the proliferation of endothelial cells compared to sham controls, indicating that the released bFGF was bioactive. ADV also triggered changes in the ultrastructure and mechanical properties of the fibrin as bubble formation and consolidation of the fibrin in ultrasound-treated composites were accompanied by up to a 22-fold increase in shear stiffness. ADV did not reduce the viability of cells suspended in composite scaffolds. These results demonstrate that an acoustic droplet-hydrogel composite could have broad utility in promoting wound healing through on-demand control of growth factor release and/or scaffold architecture. PMID:23535233

  15. Acoustic droplet–hydrogel composites for spatial and temporal control of growth factor delivery and scaffold stiffness

    PubMed Central

    Fabiilli, Mario L.; Wilson, Christopher G.; Padilla, Frédéric; Martín-Saavedra, Francisco M.; Fowlkes, J. Brian; Franceschi, Renny T.

    2013-01-01

    Wound healing is regulated by temporally and spatially restricted patterns of growth factor signaling, but there are few delivery vehicles capable of the “on-demand” release necessary for recapitulating these patterns. Recently we described a perfluorocarbon double emulsion that selectively releases a protein payload upon exposure to ultrasound through a process known as acoustic droplet vaporization (ADV). In this study, we describe a delivery system composed of fibrin hydrogels doped with growth factor-loaded double emulsion for applications in tissue regeneration. Release of immunoreactive basic fibroblast growth factor (bFGF) from the composites increased up to 5-fold following ADV and delayed release was achieved by delaying exposure to ultrasound. Releasates of ultrasound-treated materials significantly increased the proliferation of endothelial cells compared to sham controls, indicating that the released bFGF was bioactive. ADV also triggered changes in the ultrastructure and mechanical properties of the fibrin as bubble formation and consolidation of the fibrin in ultrasound-treated composites were accompanied by up to a 22-fold increase in shear stiffness. ADV did not reduce the viability of cells suspended in composite scaffolds. These results demonstrate that an acoustic droplet–hydrogel composite could have broad utility in promoting wound healing through on-demand control of growth factor release and/or scaffold architecture. PMID:23535233

  16. From glue to gasoline: how competition turns perspective takers unethical.

    PubMed

    Pierce, Jason R; Kilduff, Gavin J; Galinsky, Adam D; Sivanathan, Niro

    2013-10-01

    Perspective taking is often the glue that binds people together. However, we propose that in competitive contexts, perspective taking is akin to adding gasoline to a fire: It inflames already-aroused competitive impulses and leads people to protect themselves from the potentially insidious actions of their competitors. Overall, we suggest that perspective taking functions as a relational amplifier. In cooperative contexts, it creates the foundation for prosocial impulses, but in competitive contexts, it triggers hypercompetition, leading people to prophylactically engage in unethical behavior to prevent themselves from being exploited. The experiments reported here establish that perspective taking interacts with the relational context--cooperative or competitive--to predict unethical behavior, from using insidious negotiation tactics to materially deceiving one's partner to cheating on an anagram task. In the context of competition, perspective taking can pervert the age-old axiom "do unto others as you would have them do unto you" into "do unto others as you think they will try to do unto you."

  17. Viscoelastic, physical, and bio-degradable properties of dermal scaffolds and related cell behaviour.

    PubMed

    Sharma, Vaibhav; Patel, Nimesha; Kohli, Nupur; Ravindran, Nivedita; Hook, Lilian; Mason, Chris; García-Gareta, Elena

    2016-01-01

    Dermal scaffolds promote healing of debilitating skin injuries caused by burns and chronic skin conditions. Currently available products present disadvantages and therefore, there is still a clinical need for developing new dermal substitutes. This study aimed at comparing the viscoelastic, physical and bio-degradable properties of two dermal scaffolds, the collagen-based and clinically well established Integra(®) and a novel fibrin-based dermal scaffold developed at our laboratory called Smart Matrix(®), to further evaluate our previous published findings that suggested a higher influx of cells, reduced wound contraction and less scarring for Smart Matrix(®) when used in vivo. Rheological results showed that Integra(®) (G'  =  313.74 kPa) is mechanically stronger than Smart Matrix(®) (G'  =  8.26 kPa), due to the presence of the silicone backing layer in Integra(®). Micro-pores were observed on both dermal scaffolds, although nano-pores as well as densely packed nano-fibres were only observed for Smart Matrix(®). Average surface roughness was higher for Smart Matrix(®) (Sa  =  114.776 nm) than for Integra(®) (Sa  =  75.565 nm). Both scaffolds possess a highly porous structure (80-90%) and display a range of pore micro-sizes that represent the actual in vivo scenario. In vitro proteolytic bio-degradation suggested that Smart Matrix(®) would degrade faster upon implantation in vivo than Integra(®). For both scaffolds, the enzymatic digestion occurs via bulk degradation. These observed differences could affect cell behaviour on both scaffolds. Our results suggest that fine-tuning of scaffolds' viscoelastic, physical and bio-degradable properties can maximise cell behaviour in terms of attachment, proliferation and infiltration, which are essential for tissue repair. PMID:27586397

  18. Scaffolds in Tendon Tissue Engineering

    PubMed Central

    Longo, Umile Giuseppe; Lamberti, Alfredo; Petrillo, Stefano; Maffulli, Nicola; Denaro, Vincenzo

    2012-01-01

    Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing tendon disorders. Tissue engineering strategies to improve tendon repair healing include the use of scaffolds, growth factors, cell seeding, or a combination of these approaches. Scaffolds have been the most common strategy investigated to date. Available scaffolds for tendon repair include both biological scaffolds, obtained from mammalian tissues, and synthetic scaffolds, manufactured from chemical compounds. Preliminary studies support the idea that scaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potential. However, available data are lacking to allow definitive conclusion on the use of scaffolds for tendon augmentation. We review the current basic science and clinical understanding in the field of scaffolds and tissue engineering for tendon repair. PMID:22190961

  19. Fibrin sealant promotes migration and proliferation of human articular chondrocytes: possible involvement of thrombin and protease-activated receptors.

    PubMed

    Kirilak, Yaowanuj; Pavlos, Nathan J; Willers, Craig R; Han, Renzhi; Feng, Haotian; Xu, Jiake; Asokananthan, Nithiananthan; Stewart, Geoffrey A; Henry, Peter; Wood, David; Zheng, Ming H

    2006-04-01

    Fibrin sealant (FS), a biological adhesive material, has been recently recommended as an adjunct in autologous chondrocyte implantation (ACI). While FS has been shown to possess osteoinductive potential, little is known about its effects on chondrogenic cells. In this study, we assessed the bioactivity of FS (Tisseel) on the migration and proliferation of human articular chondrocytes in vitro. Using a co-culture assay to mimic matrix-induced ACI (MACI), chondrocytes were found to migrate from collagen membranes towards FS within 12 h of culture, with significant migratory activity evident by 24 h. In addition, 5-bromo-2'-deoxyuridine (BrdU) incorporation experiments revealed that thrombin, the active component of the tissue glue, stimulated chondrocyte proliferation, with maximal efficacy observed at 48 h post-stimulation (1-10 U/ml). In an effort to elucidate the molecular mechanisms underlying these thrombin-induced effects, we examined the expression and activation of protease-activated receptors (PARs), established thrombin receptors. Using a combination of RT-PCR and immunohistochemistry, all four PARs were detected in human chondrocytes, with PAR-1 being the major isoform expressed. Moreover, thrombin and a PAR-1, but not other PAR-isotype-specific peptide agonists, were found to induce rapid intracellular Ca2+ responses in human chondrocytes in calcium mobilization assays. Together, these data demonstrate that FS supports both the migration and proliferation of human chondrocytes. We propose that these effects are mediated, at least in part, via thrombin-induced PAR-1 signalling in human chondrocytes. PMID:16525709

  20. Kinetics of the multistep rupture of fibrin 'A-a' polymerization interactions measured using atomic force microscopy.

    PubMed

    Averett, Laurel E; Schoenfisch, Mark H; Akhremitchev, Boris B; Gorkun, Oleg V

    2009-11-18

    Fibrin, the structural scaffold of blood clots, spontaneously polymerizes through the formation of 'A-a' knob-hole bonds. When subjected to external force, the dissociation of this bond is accompanied by two to four abrupt changes in molecular dimension observable as rupture events in a force curve. Herein, the configuration, molecular extension, and kinetic parameters of each rupture event are examined. The increases in contour length indicate that the D region of fibrinogen can lengthen by approximately 50% of the length of a fibrin monomer before rupture of the 'A-a' interaction. The dependence of the dissociation rate on applied force was obtained using probability distributions of rupture forces collected at different pull-off velocities. These distributions were fit using a model in which the effects of the shape of the binding potential are used to quantify the kinetic parameters of forced dissociation. We found that the weak initial rupture (i.e., event 1) was not well approximated by these models. The ruptured bonds comprising the strongest ruptures, events 2 and 3, had kinetic parameters similar to those commonly found for the mechanical unfolding of globular proteins. The bonds ruptured in event 4 were well described by these analyses, but were more loosely bound than the bonds in events 2 and 3. We propose that the first event represents the rupture of an unknown interaction parallel to the 'A-a' bond, events 2 and 3 represent unfolding of structures in the D region of fibrinogen, and event 4 is the rupture of the 'A-a' knob-hole bond weakened by prior structural unfolding. Comparison of the activation energy obtained via force spectroscopy measurements with the thermodynamic free energy of 'A-a' bond dissociation indicates that the 'A-a' bond may be more resistant to rupture by applied force than to rupture by thermal dissociation.

  1. The relative contribution of calcium, zinc and oxidation-based cross-links to the stiffness of Arion subfuscus glue.

    PubMed

    Braun, M; Menges, M; Opoku, F; Smith, A M

    2013-04-15

    Metal ions are present in many different biological materials, and are capable of forming strong cross-links in aqueous environments. The relative contribution of different metal-based cross-links was measured in the defensive glue produced by the terrestrial slug Arion subfuscus. This glue contains calcium, magnesium, zinc, manganese, iron and copper. These metals are essential to the integrity of the glue and to gel stiffening. Removal of all metals caused at least a 15-fold decrease in the storage modulus of the glue. Selectively disrupting cross-links involving hard Lewis acids such as calcium reduced the stiffness of the glue, while disrupting cross-links involving borderline Lewis acids such as zinc did not. Calcium is the most common cation bound to the glue (40 mmol l(-1)), and its charge is balanced primarily by sulphate at 82-84 mmol l(-1). Thus these ions probably play a primary role in bringing polymers together directly. Imine bonds formed as a result of protein oxidation also contribute substantially to the stiffness of the glue. Disrupting these bonds with hydroxylamine caused a 33% decrease in storage modulus of the glue, while stabilizing them by reduction with sodium borohydride increased the storage modulus by 40%. Thus a combination of metal-based bonds operates in this glue. Most likely, cross-links directly involving calcium play a primary role in bringing together and stabilizing the polymer network, followed by imine bond formation and possible iron coordination.

  2. Influence of a constant magnetic field on the fibrinogen-fibrin system. [in blood coagulation process

    NASA Technical Reports Server (NTRS)

    Matskevichene, V. B.; Platonova, A. T.

    1974-01-01

    The effect of a constant magnetic field with a strength of 2500 oersteds on the fibrinogen-fibrin system was studied in the organism of healthy rabbits with exposure times of 1 and 5 hours. The results obtained indicate disruptions in the stage of conversion of fibrinogen to fibrin and an increase in the amount of fibrinogen.

  3. Protein unfolding accounts for the unusual mechanical behavior of fibrin networks

    PubMed Central

    Purohit, Prashant K.; Litvinov, Rustem I.; Brown, Andre E. X.; Discher, Dennis E.; Weisel, John W.

    2011-01-01

    We describe the mechanical behavior of isotropic fibrin networks at the macroscopic scale in terms of the nanoscale force response of fibrin molecules that are its basic building blocks. We show that the remarkable extensibility and compressibility of fibrin networks have their origins in the unfolding of fibrin molecules. The force-stretch behavior of a single fibrin fiber is described using a two-state model in which the fiber has a linear force-stretch relation in the folded phase and behaves like a worm-like-chain in the unfolded phase. The nanoscale force-stretch response is connected to the macro-scale stress-stretch response by means of the eight-chain model. This model is able to capture the macroscopic response of a fibrin network in uniaxial tension and appears remarkably simple given the molecular complexity. We use the eight-chain model to explain why fibrin networks have negative compressibility and Poisson’s ratio greater than one due to unfolding of fibrin molecules. PMID:21342665

  4. Modification of fibrin network ultrastructure by Fab fragments specific for different domain of fibrinogen.

    PubMed

    Cierniewski, C S; Janiak, A; Wyroba, E

    1986-01-01

    Kinetics of inhibition of fibrin monomer polymerization produced by Fab fragments prepared from immunochemically purified monospecific antibodies to the surface epitopes of different domains of fibrinogen molecule has been correlated with electron microscopic observations of resulting specimens. Fab fragments prepared from anti FgD antisera were the most efficient inhibitors of thrombin-catalysed conversion of fibrinogen to fibrin; polymerization of fibrin monomers as detected spectrophotometrically was abolished at 2:1 molar ratio of anti FgD Fab fragments to fibra monomer. These Fab fragments acting as a steric hindrance of polymerization sites inhibited the first stage of fibrin monomer aggregation. Interaction of Fab fragments derived from antibodies specific for alpha 239-476 with corresponding segment of fibrinogen molecule resulted in a weak inhibition of fibrin monomer polymerization. However, fibrin obtained in the presence of these Fab fragments was significantly modified and showed no periodicity. This observation may suggest that anti alpha 239-476 Fab impaired the course of the second stage of fibrin monomer polymerization, i.e. lateral association of fibrin fibrils.

  5. Clinical applications of naturally derived biopolymer-based scaffolds for regenerative medicine.

    PubMed

    Stoppel, Whitney L; Ghezzi, Chiara E; McNamara, Stephanie L; Black, Lauren D; Kaplan, David L

    2015-03-01

    Naturally derived polymeric biomaterials, such as collagens, silks, elastins, alginates, and fibrins are utilized in tissue engineering due to their biocompatibility, bioactivity, and tunable mechanical and degradation kinetics. The use of these natural biopolymers in biomedical applications is advantageous because they do not release cytotoxic degradation products, are often processed using environmentally-friendly aqueous-based methods, and their degradation rates within biological systems can be manipulated by modifying the starting formulation or processing conditions. For these reasons, many recent in vivo investigations and FDA-approval of new biomaterials for clinical use have utilized natural biopolymers as matrices for cell delivery and as scaffolds for cell-free support of native tissues. This review highlights biopolymer-based scaffolds used in clinical applications for the regeneration and repair of native tissues, with a focus on bone, skeletal muscle, peripheral nerve, cardiac muscle, and cornea substitutes.

  6. The presence of γ’ chain impairs fibrin polymerization

    PubMed Central

    Gersh, Kathryn C.; Nagaswami, Chandrasekaran; Weisel, John W.; Lord, Susan T.

    2009-01-01

    Introduction A fraction of fibrinogen molecules contain an alternatively spliced variant chain called γ’. Plasma levels of this variant have been associated with both myocardial infarction and venous thrombosis. Because clot structure has been associated with cardiovascular risk, we examined the effect of γ’ chain on clot structure. Materials and Methods We expressed three fibrinogen variants in Chinese hamster ovary (CHO) cells: γ/γ homodimer, γ/γ’ heterodimer, and γ’/γ’ homodimer. We observed thrombin-catalyzed fibrinopeptide release by HPLC, fibrin polymerization by turbidity, and clot structure by scanning electron microscopy. We characterized post-translational modifications by mass spectrometry. Results Fibrinopeptide A was released at the same rate for all three fibrinogens, while fibrinopeptide B was released faster from the γ’/γ’ homodimer. The rise in turbidity was slower and final absorbance was lower during polymerization of γ’-containing fibrinogens than for γ/γ fibrinogen. Micrographs showed that γ’/γ’ fibrin clots are composed of very thin fibers, while the diameter of γ/γ’ fibers is similar to γ/γ fibers. Further, the fiber networks formed from γ’-containing samples were non-uniform. Mass spectrometry showed heterogeneous addition of N-glycans and tyrosine sulfation in the γ’ chain. Conclusions The presence of γ’ chains slows lateral aggregation and alters fibrin structure. We suggest these changes are likely due to charge-charge repulsion, such that polymerization of the γ’/γ’ homodimer is more impaired than the heterodimer since these repulsions are partially offset by incorporation of γ chains in the γ/γ’ heterodimer. PMID:19138790

  7. Application of COMPONT Medical Adhesive Glue for Tension-Reduced Duraplasty in Decompressive Craniotomy

    PubMed Central

    Zhou, Yujia; Wang, Gesheng; Liu, Jialin; Du, Yong; Wang, Lei; Wang, Xiaoyong

    2016-01-01

    Background The aim of this study was to evaluate the application of medical adhesive glue for tension-reduced duraplasty in decompressive craniotomy. Material/Methods A total of 56 cases were enrolled for this study from Jan 2013 to May 2015. All patients underwent decompressive craniotomy and the dura was repaired in all of them with tension-reduced duraplasty using the COMPONT medical adhesive to glue artificial dura together. The postoperative complications and the healing of dura mater were observed and recorded. Results No wound infection, epidural or subdural hematoma, cerebrospinal fluid leakage, or other complications associated with the procedure occurred, and there were no allergic reactions to the COMPONT medical adhesive glue. The second-phase surgery of cranioplasty was performed at 3 to 6 months after the decompressive craniotomy in 32 out of the 56 cases. During the cranioplasty we observed no adherence of the artificial dura mater patch to the skin flap, no residual COMPONT glue, or hydropic or contracture change of tissue at the surgical sites. Additionally, no defect or weakening of the adherence between the artificial dura mater patch and the self dura matter occurred. Conclusions COMPONT medical adhesive glue is a safe and reliable tool for tension-reduced duraplasty in decompressive craniotomy. PMID:27752035

  8. Ubiquitous distribution of salts and proteins in spider glue enhances spider silk adhesion

    NASA Astrophysics Data System (ADS)

    Amarpuri, Gaurav; Chaurasia, Vishal; Jain, Dharamdeep; Blackledge, Todd A.; Dhinojwala, Ali

    2015-03-01

    Modern orb-weaving spiders use micron-sized glue droplets on their viscid silk to retain prey in webs. A combination of low molecular weight salts and proteins makes the glue viscoelastic and humidity responsive in a way not easily achieved by synthetic adhesives. Optically, the glue droplet shows a heterogeneous structure, but the spatial arrangement of its chemical components is poorly understood. Here, we use optical and confocal Raman microscopy to show that salts and proteins are present ubiquitously throughout the droplet. The distribution of adhesive proteins in the peripheral region explains the superior prey capture performance of orb webs as it enables the entire surface area of the glue droplet to act as a site for prey capture. The presence of salts throughout the droplet explains the recent Solid-State NMR results that show salts directly facilitate protein mobility. Understanding the function of individual glue components and the role of the droplet's macro-structure can help in designing better synthetic adhesives for humid environments.

  9. Tracing the biological origin of animal glues used in paintings through mitochondrial DNA analysis.

    PubMed

    Albertini, Emidio; Raggi, Lorenzo; Vagnini, Manuela; Sassolini, Alessandro; Achilli, Alessandro; Marconi, Gianpiero; Cartechini, Laura; Veronesi, Fabio; Falcinelli, Mario; Brunetti, Brunetto Giovanni; Miliani, Costanza

    2011-03-01

    We report the development of a suitable protocol for the identification of the biological origin of binding media on tiny samples from ancient paintings, by exploitation of the high specificity and high sensitivity offered by the state-of-the art DNA analysis. In particular, our aim was to molecularly characterize mitochondrial regions of the animal species traditionally employed for obtaining glues. The model has been developed using aged painting models and then tested to analyze the organic components in samples from the polychrome terracotta Madonna of Citerna by Donatello (1415-1420), where, by GC-MS and FTIR spectroscopy, animal glues and siccative oils were identified. The results obtained are good in terms of both sensibility and specificity of the method. First of all, it was possible to confirm that Donatello used animal glue for the preparation of the painted layers of the Madonna of Citerna and, specifically, glue derived from Bos taurus. Data obtained from sequencing confirm that each sample contains animal glue, revealing that it was mostly prepared from two common European taurine lineages called T2 and T3. There is one remarkable exception represented by one sample which falls into a surviving lineage of the now extinct European aurochs.

  10. Ubiquitous distribution of salts and proteins in spider glue enhances spider silk adhesion.

    PubMed

    Amarpuri, Gaurav; Chaurasia, Vishal; Jain, Dharamdeep; Blackledge, Todd A; Dhinojwala, Ali

    2015-01-01

    Modern orb-weaving spiders use micron-sized glue droplets on their viscid silk to retain prey in webs. A combination of low molecular weight salts and proteins makes the glue viscoelastic and humidity responsive in a way not easily achieved by synthetic adhesives. Optically, the glue droplet shows a heterogeneous structure, but the spatial arrangement of its chemical components is poorly understood. Here, we use optical and confocal Raman microscopy to show that salts and proteins are present ubiquitously throughout the droplet. The distribution of adhesive proteins in the peripheral region explains the superior prey capture performance of orb webs as it enables the entire surface area of the glue droplet to act as a site for prey capture. The presence of salts throughout the droplet explains the recent Solid-State NMR results that show salts directly facilitate protein mobility. Understanding the function of individual glue components and the role of the droplet's macro-structure can help in designing better synthetic adhesives for humid environments. PMID:25761668

  11. Self-supported fibrin-polyvinyl alcohol interpenetrating polymer networks: an easily handled and rehydratable biomaterial.

    PubMed

    Bidault, Laurent; Deneufchatel, Marie; Vancaeyzeele, Cédric; Fichet, Odile; Larreta-Garde, Véronique

    2013-11-11

    A fibrin hydrogel at physiological concentration (5 mg/mL) was associated with polyvinyl alcohol (PVA) inside an interpenetrating polymer networks (IPN) architecture. Previously, PVA has been modified with methacrylate functions in order to cross-link it by free-radical polymerization. The fibrin network was synthesized by the enzymatic hydrolysis of fibrinogen by thrombin. The resulting self-supported materials simultaneously exhibit the properties of the fibrin hydrogel and those of the synthetic polymer network. Their storage modulus is 50-fold higher than that of the fibrin hydrogel and they are completely rehydratable. These materials are noncytotoxic toward human fibroblast and the fibrin present on the surface of PVAm-based IPNs favors cell development.

  12. Longitudinal orientation of cross-linked polypeptide γ chains in fibrin fibrils.

    PubMed

    Rosenfeld, M A; Leonova, V B; Bychkova, A V; Kostanova, E A; Biryukova, M I

    2015-01-01

    The crosslinking of fibrin γ-polypeptide chains under the influence of the plasma fibrin-stabilizing factor (FXIIIa), which causes their conversion to γ-γ dimers, is the major enzyme reaction of covalent fibrin stabilization. We studied the self-assembly of soluble cross-linked fibrin oligomers. The results of analytical ultracentrifugation as well as elastic and dynamic light scattering showed that the double-stranded fibrin oligomers formed under the influence of moderate concentrations of urea are cross-linked only due to formation of γ-γ dimers, which can dissociate into single-stranded structure when the concentration of urea increases. This fact proves that γ-γ dimers are formed in the end-to-end manner. PMID:26518549

  13. Fibrin Clots Are Equilibrium Polymers That Can Be Remodeled Without Proteolytic Digestion

    NASA Astrophysics Data System (ADS)

    Chernysh, Irina N.; Nagaswami, Chandrasekaran; Purohit, Prashant K.; Weisel, John W.

    2012-11-01

    Fibrin polymerization is a necessary part of hemostasis but clots can obstruct blood vessels and cause heart attacks and strokes. The polymerization reactions are specific and controlled, involving strong knob-into-hole interactions to convert soluble fibrinogen into insoluble fibrin. It has long been assumed that clots and thrombi are stable structures until proteolytic digestion. On the contrary, using the technique of fluorescence recovery after photobleaching, we demonstrate here that there is turnover of fibrin in an uncrosslinked clot. A peptide representing the knobs involved in fibrin polymerization can compete for the holes and dissolve a preformed fibrin clot, or increase the fraction of soluble oligomers, with striking rearrangements in clot structure. These results imply that in vivo clots or thrombi are more dynamic structures than previously believed that may be remodeled as a result of local environmental conditions, may account for some embolization, and suggest a target for therapeutic intervention.

  14. Revitalization of traumatized immature tooth with platelet-rich fibrin

    PubMed Central

    Faizuddin, Umrana; Solomon, Raji Viola; Mattapathi, Jayadev; Guniganti, Sushma Shravani

    2015-01-01

    Endodontic treatment options for immature, nonvital teeth conventionally include surgical endodontics, apexification with calcium hydroxide, or single visit mineral trioxide aggregate plug. Regeneration is a new concept which is been introduced in the treatment of traumatized open apex tooth. Regeneration of pulp-dentin complex in an infected necrotic tooth with an open apex is possible if the canal is effectively disinfected. The purpose of this case report is to add a new vista in regenerative, endodontic therapy by using platelet-rich fibrin for revitalization of immature nonvital tooth. PMID:26681870

  15. Platelet-rich fibrin application in dentistry: a literature review

    PubMed Central

    Borie, Eduardo; Oliví, Daniel García; Orsi, Iara Augusta; Garlet, Katia; Weber, Benjamín; Beltrán, Víctor; Fuentes, Ramón

    2015-01-01

    The development of bioactive surgical additives to regulate the inflammation and increase the speed of healing process is one of the great challenges in clinical research. In this sense, platelet rich fibrin (PRF) appears as a natural and satisfactory alternative with favorable results and low risks. The following review attempts to summarize the relevant literature regarding the technique of using PRF, focusing on its preparation, advantages, and disadvantages of using it in clinical applications. PRF alone or in combination with other biomaterials seems to have several advantages and indications both for medicine and dentistry, due it is a minimally invasive technique with low risks and satisfactory clinical results. PMID:26221349

  16. Biomimetic Scaffolds for Osteogenesis

    PubMed Central

    Yuan, Nance; Rezzadeh, Kameron S.; Lee, Justine C.

    2015-01-01

    Skeletal regenerative medicine emerged as a field of investigation to address large osseous deficiencies secondary to congenital, traumatic, and post-oncologic conditions. Although autologous bone grafts have been the gold standard for reconstruction of skeletal defects, donor site morbidity remains a significant limitation. To address these limitations, contemporary bone tissue engineering research aims to target delivery of osteogenic cells and growth factors in a defined three dimensional space using scaffolding material. Using bone as a template, biomimetic strategies in scaffold engineering unite organic and inorganic components in an optimal configuration to both support osteoinduction as well as osteoconduction. This article reviews the various structural and functional considerations behind the development of effective biomimetic scaffolds for osteogenesis and highlights strategies for enhancing osteogenesis. PMID:26413557

  17. Systems level approach reveals the correlation of endoderm differentiation of mouse embryonic stem cells with specific microstructural cues of fibrin gels.

    PubMed

    Task, Keith; D'Amore, Antonio; Singh, Satish; Candiello, Joe; Jaramillo, Maria; Wagner, William R; Kumta, Prashant; Banerjee, Ipsita

    2014-06-01

    Stem cells receive numerous cues from their associated substrate that help to govern their behaviour. However, identification of influential substrate characteristics poses difficulties because of their complex nature. In this study, we developed an integrated experimental and systems level modelling approach to investigate and identify specific substrate features influencing differentiation of mouse embryonic stem cells (mESCs) on a model fibrous substrate, fibrin. We synthesized a range of fibrin gels by varying fibrinogen and thrombin concentrations, which led to a range of substrate stiffness and microstructure. mESCs were cultured on each of these gels, and characterization of the differentiated cells revealed a strong influence of substrate modulation on gene expression patterning. To identify specific substrate features influencing differentiation, the substrate microstructure was quantified by image analysis and correlated with stem cell gene expression patterns using a statistical model. Significant correlations were observed between differentiation and microstructure features, specifically fibre alignment. Furthermore, this relationship occurred in a lineage-specific manner towards endoderm. This systems level approach allows for identification of specific substrate features from a complex material which are influential to cellular behaviour. Such analysis may be effective in guiding the design of scaffolds with specific properties for tissue engineering applications.

  18. Towards an ideal polymer scaffold for tendon/ligament tissue engineering

    NASA Astrophysics Data System (ADS)

    Sahoo, Sambit; Ouyang, Hong Wei; Goh, James Cho-Hong; Tay, Tong-Earn; Toh, Siew Lok

    2005-04-01

    Tissue engineering holds promise in treating injured tendons and ligaments by replacing the injured tissues with "engineered tissues" with identical mechanical and functional characteristics. A biocompatible, biodegradable, porous scaffold with optimized architecture, sufficient surface area for cell attachment, growth and proliferation, faborable mechanical properties, and suitable degradation rate is a pre-requisite to achieve success with this aproach. Knitted poly(lactide-co-glycolide) (PLGA) scaffolds comprising of microfibers of 25 micron diameter were coated with PLGA nanofibers on their surfaces by electrospinning technique. A cell suspension of pig bone marrow stromal cells (BMSC) was seeded on the scaffolds by pipetting, and the cell-scaffold constructs were cultured in a CO2 incubator, at 37°C for 1-2 weeks. The "engineered tissues" were then assessed for cell attachment and proliferation, tissue formation, and mechanical properties. Nanofibers, of diameter 300-900 nm, were spread randomly over the knitted scaffold. The reduction in pore-size from about 1 mm (in the knitted scaffold) to a few micrometers (in the nano-microscaffold) allowed cell seeding by direct pipetting, and eliminated the need of a cell-delivery system like fibrin gel. BMSCs were seen to attach and proliferate well on the nano-microscaffold, producing abundant extracellular matrix. Mechanical testing revealed that the cell-seeded nano-microscaffolds possessed slightly higher values of failure load, elastic-region stiffness and toe-region stiffness, than the unseeded scaffolds. The combination of superior mechanical strength and integrity of knitted microfibers, with the large surface area and improved hydrophilicity of the electrospun nanofibers facilitated cell attachment and new tissue formation. This holds promise in tissue engineering of tendon/ligament.

  19. Hardness of Al-based quasicrystals evaluated via cluster-plus-glue-atom model

    NASA Astrophysics Data System (ADS)

    Chen, Hua; Luo, Lingjie; Qiang, Jianbing; Wang, Yingmin; Dong, Chuang

    2014-05-01

    In this paper, the hardness of ternary Al-based quasicrystals was assessed through an application of the cluster-plus-glue-atom model. In this model, any structure is decomposed into a first-neighbour strongly bonded cluster part and second-neighbour weakly bonded glue-atom part so that the overall structural information is condensed into a local structural unit [cluster](glue atom)x. For quasicrystals, the averaged local units are formulated as [icosahedron] TM0,1(Transition Metal) and could be visualized as single icosahedron packing. Then, the hardness of quasicrystals was related to the rupture of weak inter-cluster bonds. Typically, theoretical hardness values of 8-9 GPa were obtained using 19 broken inter-cluster bonds, which accounts for about half of all the surface bonds of an icosahedron in the Mackay-type environment. The unit cluster formulas would act as rigid units during deformation and cracking.

  20. Application of the silicon photomultipliers for detectors in the GlueX experiment

    SciTech Connect

    Somov, Sergey V.; Tolstukhin, Ivan; Somov, Alexander S.

    2015-11-01

    The GlueX detector in Hall D at Jefferson Lab is instrumented with about 5000 Silicon Photomultipliers (SiPM) manufactured by Hamamatsu Corporation [2]. These photo sensors have properties similar to conventional photomultipliers but can be operated at high magnetic fields. Silicon photomultipliers with a sensitive area of 3x3 mm2 are used to detect light from the following GlueX scintillator detectors: the tagger microscope, pair spectrometer, and start counter. Arrays of 4x4 SiPMs sensors were chosen for the instrumentation of the barrel electromagnetic calorimeter. The tagger microscope must operate at high rates (up to 2.5 MHz) and provide time measurements with a resolution better than 0.3 ns. The paper will describe some results of the characterization of SiPMs for various GlueX sub-detectors.

  1. Exotic Hybrid Meson Spectroscopy with the GlueX detector at Jlab

    SciTech Connect

    Lawrence, David W.

    2014-03-01

    The GlueX experiment is scheduled to begin taking data in 2015. The goal is to discover evidence for the existence of exotic hybrid mesons and to map out their spectrum in the light quark sector. Recent theoretical developments using Lattice QCD predict exotic hybrid states in a mass range accessible using the newly upgraded 12GeV electron accelerator at Jefferson Lab. Hybrid mesons, and in particular exotic hybrid mesons, provide the ideal laboratory for testing QCD in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom. The experiment will use 9 GeV linearly polarized photons produced via coherent bremsstrahlung to produce the exotic hybrids. The decay products will be detected in the solenoid-based GlueX detector currently under construction at Jefferson Lab. The status of the GlueX experiment including detector parameters will be presented along with theoretical motivation for the experiment.

  2. L_RNA_scaffolder: scaffolding genomes with transcripts

    PubMed Central

    2013-01-01

    Background Generation of large mate-pair libraries is necessary for de novo genome assembly but the procedure is complex and time-consuming. Furthermore, in some complex genomes, it is hard to increase the N50 length even with large mate-pair libraries, which leads to low transcript coverage. Thus, it is necessary to develop other simple scaffolding approaches, to at least solve the elongation of transcribed fragments. Results We describe L_RNA_scaffolder, a novel genome scaffolding method that uses long transcriptome reads to order, orient and combine genomic fragments into larger sequences. To demonstrate the accuracy of the method, the zebrafish genome was scaffolded. With expanded human transcriptome data, the N50 of human genome was doubled and L_RNA_scaffolder out-performed most scaffolding results by existing scaffolders which employ mate-pair libraries. In these two examples, the transcript coverage was almost complete, especially for long transcripts. We applied L_RNA_scaffolder to the highly polymorphic pearl oyster draft genome and the gene model length significantly increased. Conclusions The simplicity and high-throughput of RNA-seq data makes this approach suitable for genome scaffolding. L_RNA_scaffolder is available at http://www.fishbrowser.org/software/L_RNA_scaffolder. PMID:24010822

  3. Acute and chronic glue sniffing effects and consequences of withdrawal on aggressive behavior.

    PubMed

    Bouchatta, Otmane; Ouhaz, Zakaria; Ba-Mhamed, Saadia; Kerekes, Nóra; Bennis, Mohamed

    2016-05-01

    Drug abuse act on brain mechanisms that cause a high-risk individual to engage in aggressive and violent behavior. While a drug-violence relationship exists, the nature of this relationship is often complex, with intoxication, neurotoxic, and withdrawal effects often being confused and/or confounded. Glue sniffing is often a springboard to the abuse of more addictive drugs. Despite its high prevalence and serious consequences, we know relatively little about the aggressive behavioral effects of volatile inhalants abuse, especially glue. The aim of the present study was to investigate the link between the duration of glue exposure, a common substance abuse problem in Morocco, and the level of aggressive behavior during withdrawal. For this we used the isolation-induced aggression model "residents" in three groups of mice. The first group served as control resident animals (n=10, without exposure); the second group as experimental resident mice (n=10) tested before and after acute (first day) and chronic exposure to the glue, and at 1 and 2weeks of withdrawal; and the third group of 10 intruder animals. The results showed that the number of attacks decreased (halved) and the latency of the first attack increased (doubled) following acute glue sniffing. However, the effects of chronic exposure and of 1week of withdrawal led to an increase in the intensity of agonistic encounters. After 2weeks of withdrawal, the intensity of aggressive behavior decreased again. These results indicated that chronic glue exposure and the first week of withdrawal are associated with increased aggression in mice. PMID:26969766

  4. Use of Autologous Human mesenchymal Stromal Cell/Fibrin Clot Constructs in Upper Limb Non-Unions: Long-Term Assessment

    PubMed Central

    Bottai, Vanna; Ghilardi, Marco; D'Alessandro, Delfo; Danti, Serena; Dell'Osso, Giacomo; Guido, Giulio; Petrini, Mario

    2013-01-01

    Background Tissue engineering appears to be an attractive alternative to the traditional approach in the treatment of fracture non-unions. Mesenchymal stromal cells (MSCs) are considered an appealing cell source for clinical intervention. However, ex vivo cell expansion and differentiation towards the osteogenic lineage, together with the design of a suitable scaffold have yet to be optimized. Major concerns exist about the safety of MSC-based therapies, including possible abnormal overgrowth and potential cancer evolution. Aims We examined the long-term efficacy and safety of ex vivo expanded bone marrow MSCs, embedded in autologous fibrin clots, for the healing of atrophic pseudarthrosis of the upper limb. Our research work relied on three main issues: use of an entirely autologous context (cells, serum for ex vivo cell culture, scaffold components), reduced ex vivo cell expansion, and short-term MSC osteoinduction before implantation. Methods and Findings Bone marrow MSCs isolated from 8 patients were expanded ex vivo until passage 1 and short-term osteo-differentiated in autologous-based culture conditions. Tissue-engineered constructs designed to embed MSCs in autologous fibrin clots were locally implanted with bone grafts, calibrating their number on the extension of bone damage. Radiographic healing was evaluated with short- and long-term follow-ups (range averages: 6.7 and 76.0 months, respectively). All patients recovered limb function, with no evidence of tissue overgrowth or tumor formation. Conclusions Our study indicates that highly autologous treatment can be effective and safe in the long-term healing of bone non-unions. This tissue engineering approach resulted in successful clinical and functional outcomes for all patients. PMID:24023694

  5. Biofunctionalized Calcium Phosphate Cement to Enhance the Attachment and Osteodifferentiation of Stem Cells Released from Fast-Degradable Alginate-Fibrin Microbeads

    PubMed Central

    Chen, Wenchuan; Weir, Michael D.

    2012-01-01

    Stem cell-encapsulating microbeads could be mixed into a paste such as calcium phosphate cement (CPC), where the microbeads could protect the cells from the mixing and injection forces. After being placed, the microbeads could quickly degrade to release the cells throughout the scaffold, while creating macropores. The objectives of this study were to (1) construct alginate-fibrin microbeads encapsulating human umbilical cord mesenchymal stem cells (hUCMSCs) embedded in the surface of novel biofunctionalized CPC and (2) investigate microbead degradation, cell release, and osteodifferentiation on CPC. Hydrogel microbeads were fabricated that encapsulated hUCMSCs at 1×106 cells/mL. CPC was biofunctionalized with fibronectin (Fn) and Arg-Gly-Asp (RGD). Four scaffolds were tested: CPC control, CPC mixed with Fn, CPC mixed with RGD, and CPC grafted with RGD. The degradable microbeads released hUCMSCs at 7 days, which attached to CPC. Adding Fn or RGD to CPC greatly improved cell attachment. CPC grafted with RGD showed the fastest cell proliferation, with cell density being ninefold that on CPC control. The released hUCMSCs underwent osteodifferentiation. Alkaline phosphatase, osteocalcin, collagen 1, and runt-related transcription factor 2 (Runx2) gene expression increased by 10 to 30 fold at 7–21 days, compared with day 1. The released cells on CPC synthesized bone minerals, with the mineralization amount at 21 days being two orders of magnitude higher than that at 7 days. In conclusion, alginate-fibrin microbeads embedded in CPC surface were able to quickly release the hUCMSCs that attached to biofunctionalized CPC. Incorporating Fn and RGD into CPC greatly improved cell function, and CPC grafted with RGD had the fastest cell proliferation. The released cells on CPC differentiated into the osteogenic lineage and synthesized bone minerals. The new biofunctionalized CPC with hUCMSC-encapsulating microbeads is promising for bone regeneration applications. PMID:22435653

  6. Migration of keratinocytes through tunnels of digested fibrin

    NASA Astrophysics Data System (ADS)

    Ronfard, Vincent; Barrandon, Yann

    2001-04-01

    We report here a hitherto undescribed form of cell migration. When a suspension of human keratinocytes is plated on a fibrin matrix, single cells invade the matrix and progress through it as rounded cells by dissolving the fibrin and thereby creating tunnels. These tunnels are cylindrical or helical, the latter being the result of constant change in the path of cellular advance around the helical axis. Helical tunnel formation is strongly promoted by epidermal growth factor. The rate of migration of the cell through the track of a helical tunnel (up to 2.1 mm per day) is about 7-fold greater than through a cylindrical tunnel. Pericellular fibrinolysis leading to tunnel formation depends on the presence of plasminogen in the medium and its conversion to plasmin by a cellular activator. Formation of tunnels requires that plasminogen activator be localized on the advancing surface of the keratinocyte; we propose that the tunnel is cylindrical when the site of release of plasmin is located at a fixed point on the cell surface and helical when the site of release precesses.

  7. Soft fibrin gels promote selection and growth of tumorigenic cells

    NASA Astrophysics Data System (ADS)

    Liu, Jing; Tan, Youhua; Zhang, Huafeng; Zhang, Yi; Xu, Pingwei; Chen, Junwei; Poh, Yeh-Chuin; Tang, Ke; Wang, Ning; Huang, Bo

    2012-08-01

    The identification of stem-cell-like cancer cells through conventional methods that depend on stem cell markers is often unreliable. We developed a mechanical method for selecting tumorigenic cells by culturing single cancer cells in fibrin matrices of ~100 Pa in stiffness. When cultured within these gels, primary human cancer cells or single cancer cells from mouse or human cancer cell lines grew within a few days into individual round colonies that resembled embryonic stem cell colonies. Subcutaneous or intravenous injection of 10 or 100 fibrin-cultured cells in syngeneic or severe combined immunodeficiency mice led to the formation of solid tumours at the site of injection or at the distant lung organ much more efficiently than control cancer cells selected using conventional surface marker methods or cultured on conventional rigid dishes or on soft gels. Remarkably, as few as ten such cells were able to survive and form tumours in the lungs of wild-type non-syngeneic mice.

  8. Functional properties of cell-seeded three-dimensionally woven poly(epsilon-caprolactone) scaffolds for cartilage tissue engineering.

    PubMed

    Moutos, Franklin T; Guilak, Farshid

    2010-04-01

    Articular cartilage possesses complex mechanical properties that provide healthy joints the ability to bear repeated loads and maintain smooth articulating surfaces over an entire lifetime. In this study, we utilized a fiber-reinforced composite scaffold designed to mimic the anisotropic, nonlinear, and viscoelastic biomechanical characteristics of native cartilage as the basis for developing functional tissue-engineered constructs. Three-dimensionally woven poly(epsilon-caprolactone) (PCL) scaffolds were encapsulated with a fibrin hydrogel, seeded with human adipose-derived stem cells, and cultured for 28 days in chondrogenic culture conditions. Biomechanical testing showed that PCL-based constructs exhibited baseline compressive and shear properties similar to those of native cartilage and maintained these properties throughout the culture period, while supporting the synthesis of a collagen-rich extracellular matrix. Further, constructs displayed an equilibrium coefficient of friction similar to that of native articular cartilage (mu(eq) approximately 0.1-0.3) over the prescribed culture period. Our findings show that three-dimensionally woven PCL-fibrin composite scaffolds can be produced with cartilage-like mechanical properties, and that these engineered properties can be maintained in culture while seeded stem cells regenerate a new, functional tissue construct.

  9. Computational Parametric Analysis of Mechanical Behaviors of Celotex Implanted with Glue Plates

    SciTech Connect

    Gong, C.

    2001-02-20

    The purpose of this analysis of the Celotex implanted with glue plates is two-fold, first is to identify the cause of the initial stress peak in the pseudo engineering stress-strain curve in the dynamic impact test that the impact is loaded in the orientation parallel to the plane of the glue. Secondly, from the existing static mechanical properties to derive the true constitutive properties of the Celotex under dynamic impact and other environmental conditions, such as warm (250 degrees Fahrenheit), wet (100 percent relative humidity), cold (minus 40 degrees Fahrenheit), and desiccated.

  10. Mathematical Abstraction through Scaffolding

    ERIC Educational Resources Information Center

    Ozmantar, Mehmet Fatih; Roper, Tom

    2004-01-01

    This paper examines the role of scaffolding in the process of abstraction. An activity-theoretic approach to abstraction in context is taken. This examination is carried out with reference to verbal protocols of two 17 year-old students working together on a task connected to sketching the graph of |f|x|)|. Examination of the data suggests that…

  11. Novel predictors for immediate puncture site bleed during endoscopic glue injection for gastric varices without using lipiodol.

    PubMed

    Chandrasekar, T S; Menachery, John; Gokul, B J; Murugesh, M; Vivek Sandeep, T C

    2013-05-01

    Endoscopic obturation of gastric varices using tissue adhesive glues like cyanoacrylate is an accepted modality for the treatment of gastric varices. This study was undertaken to determine whether it was possible to predict immediate puncture site bleed on withdrawal of needle catheter during endoscopic glue injection without lipiodol. We prospectively analyzed 100 consecutive patients with cirrhosis who underwent glue injection. Glue injection was successful in all the patients. Immediate puncture site bleed was observed in only four cases and all of them correlated with negative catheter pull sign and positive red catheter sign. Catheter pull sign and red catheter sign were excellent predictors of immediate puncture site bleed during endoscopic glue injection and should be routinely tested.

  12. Preparation and characterization of fibrous chitosan-glued phosphate glass fiber scaffolds for bone regeneration.

    PubMed

    Zheng, Kai; Wu, Zhaoying; Wei, Jie; Rűssel, Christian; Liang, Wen; Boccaccini, Aldo R

    2015-08-01

    Phosphate glass fibers (PGF) have emerged as promising building blocks for constructing bone scaffolds. In this study, fibrous scaffolds (PGFS) were fabricated using a facile binding method at room temperature. PGFS exhibited an extracellular matrix-like morphology and were composed of PGF as matrix and chitosan as the natural binding glue. They showed an interconnected porous structure with a porosity of ~87% and pore size of 100-500 µm. PGFS exhibited the typical compressive stress-strain behaviour of highly porous, low-density, open-cell scaffolds. Their yield stress and modulus were ~0.38 and ~2.84 MPa, respectively, with the strength being higher than the lower bound of the compressive strength of cancellous bone. PGFS were degradable and the weight loss was about 25% after immersion in stimulated body fluid (SBF) for 28 days. In addition, the yield stress and the modulus decreased with increasing immersion time in SBF. Apatite formation could be detected on the surface of PGFS within 7 days of immersion in SBF. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay indicated that PGFS were non-cytotoxic against bone marrow stromal cells (bMSCs) after culture for up to 72 h. These results suggest that PGFS could be promising scaffolds for bone regeneration applications. PMID:26271217

  13. The configuration of fibrin clots determines capillary morphogenesis and endothelial cell migration.

    PubMed

    Nehls, V; Herrmann, R

    1996-05-01

    In the living organism, capillary growth frequently occurs in a fibrin-rich extracellular matrix. The structure and the mechanical properties of fibrin clots are influenced by various macromolecules (i.e., hyaluronic acid and thrombospondin) and also by pH, ionic strength, and thrombin concentrations of the milieu in which they polymerize. The configuration (three-dimensional architecture) and the rigidity of fibrin clots correlate with their opacity measured by spectrophotometric absorbance readings at 350 nm. By using bovine pulmonary artery endothelial cells and bovine fibrinogen, we show here that transparent fibrin clots (A(350) < 1.0), polymerized at > or = pH 7.5 or in the presence of increased thrombin or sodium chloride concentrations, strongly stimulated capillary morphogenesis in vitro. In contrast, opaque fibrin gels (A(350) > 1.5), polymerized at pH 7.2 or in the presence of dextran, stimulated only the migration of endothelial cells but not capillary morphogenesis. We demonstrate that the angiomorphogenic effects of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) are strongly dependent on the structure of the fibrin clots. Our findings suggest that bFGF/VEGF primarily stimulate the proliferation of endothelial cells, whereas the three-dimensional architecture of the fibrin matrix is decisive for capillary morphogenesis. PMID:8992233

  14. Intramedullary anchoring strength of titanium rod with mixed beta-tricalcium phosphate and fibrin adhesive.

    PubMed

    Oyake, Yuichiro; Beppu, Moroe; Ishii, Shoji; Takagi, Masayuki; Takashi, Masahisa

    2002-01-01

    Histological and biomechanical studies were conducted in Japanese white rabbits to evaluate the effect of mixed beta-tricalcium phosphate (beta-TCP) and fibrin adhesive on bone formation around a titanium rod in femoral bone marrow. The animals received injections of fibrin adhesive with beta-TCP or hydroxyapatite into the femoral bone marrow from the distal end of the femur, where a titanium rod was inserted. Group I received fibrin adhesive only, group II received fibrin adhesive and hydroxyapatite (HA), and group III received fibrin adhesive and beta-TCP. On the examination of nondecalcified specimens, group III showed cross-bridging bone formation between beta-TCP particles at week 8, this being observed earlier than in group II. On mechanical evaluation, group III showed significant differences in maximum pull-out force at week 8, and in modulus of rigidity at week 24, compared with the other groups. On the examination of decalcified specimens, chronic inflammation was clearly identified in group I at week 8, and residual beta-TCP particles were found in group III at week 24. These results suggest that the mixture given to group III filled bone defects around the rod and promoted bone formation at a relatively early stage. Inflammation and delayed absorption of beta-TCP, which appeared to be a reaction of heterologous fibrins, caused delays in bone formation promoted by beta-TCP. Nevertheless, the use of fibrin adhesive appears to be a feasible method for loading powdered beta-TCP. PMID:11819144

  15. Thrombin-dependent Incorporation of von Willebrand Factor into a Fibrin Network*

    PubMed Central

    Miszta, Adam; Pelkmans, Leonie; Lindhout, Theo; Krishnamoorthy, Ganeshram; de Groot, Philip G.; Hemker, Coenraad H.; Heemskerk, Johan W. M.; Kelchtermans, Hilde; de Laat, Bas

    2014-01-01

    Attachment of platelets from the circulation onto a growing thrombus is a process involving multiple platelet receptors, endothelial matrix components, and coagulation factors. It has been indicated previously that during a transglutaminase reaction activated factor XIII (FXIIIa) covalently cross-links von Willebrand factor (VWF) to polymerizing fibrin. Bound VWF further recruits and activates platelets via interactions with the platelet receptor complex glycoprotein Ib (GPIb). In the present study we found proof for binding of VWF to a fibrin monomer layer during the process of fibrinogen-to-fibrin conversion in the presence of thrombin, arvin, or a snake venom from Crotalus atrox. Using a domain deletion mutant we demonstrated the involvement of the C domains of VWF in this binding. Substantial binding of VWF to fibrin monomers persisted in the presence of the FXIIIa inhibitor K9-DON, illustrating that cross-linking via factor XIII is not essential for this phenomenon and suggesting the identification of a second mechanism through which VWF multimers incorporate into a fibrin network. Under high shear conditions, platelets were shown to adhere to fibrin only if VWF had been incorporated. In conclusion, our experiments show that the C domains of VWF and the E domain of fibrin monomers are involved in the incorporation of VWF during the polymerization of fibrin and that this incorporation fosters binding and activation of platelets. Fibrin thus is not an inert end product but partakes in further thrombus growth. Our findings help to elucidate the mechanism of thrombus growth and platelet adhesion under conditions of arterial shear rate. PMID:25381443

  16. Thrombin-dependent Incorporation of von Willebrand Factor into a Fibrin Network.

    PubMed

    Miszta, Adam; Pelkmans, Leonie; Lindhout, Theo; Krishnamoorthy, Ganeshram; de Groot, Philip G; Hemker, Coenraad H; Heemskerk, Johan W M; Kelchtermans, Hilde; de Laat, Bas

    2014-12-26

    Attachment of platelets from the circulation onto a growing thrombus is a process involving multiple platelet receptors, endothelial matrix components, and coagulation factors. It has been indicated previously that during a transglutaminase reaction activated factor XIII (FXIIIa) covalently cross-links von Willebrand factor (VWF) to polymerizing fibrin. Bound VWF further recruits and activates platelets via interactions with the platelet receptor complex glycoprotein Ib (GPIb). In the present study we found proof for binding of VWF to a fibrin monomer layer during the process of fibrinogen-to-fibrin conversion in the presence of thrombin, arvin, or a snake venom from Crotalus atrox. Using a domain deletion mutant we demonstrated the involvement of the C domains of VWF in this binding. Substantial binding of VWF to fibrin monomers persisted in the presence of the FXIIIa inhibitor K9-DON, illustrating that cross-linking via factor XIII is not essential for this phenomenon and suggesting the identification of a second mechanism through which VWF multimers incorporate into a fibrin network. Under high shear conditions, platelets were shown to adhere to fibrin only if VWF had been incorporated. In conclusion, our experiments show that the C domains of VWF and the E domain of fibrin monomers are involved in the incorporation of VWF during the polymerization of fibrin and that this incorporation fosters binding and activation of platelets. Fibrin thus is not an inert end product but partakes in further thrombus growth. Our findings help to elucidate the mechanism of thrombus growth and platelet adhesion under conditions of arterial shear rate. PMID:25381443

  17. Proangiogenic Hydrogels Within Macroporous Scaffolds Enhance Islet Engraftment in an Extrahepatic Site

    PubMed Central

    Brady, Ann-Christina; Martino, Mikaël M.; Pedraza, Eileen; Sukert, Steve; Pileggi, Antonello; Ricordi, Camillo; Hubbell, Jeffrey A.

    2013-01-01

    The transplantation of allogeneic islets in recent clinical trials has shown substantial promise as a therapy for type 1 diabetes; however, long-term insulin independence remains inadequate. This has been largely attributed to the current intravascular, hepatic transplant site, which exposes islets to mechanical and inflammatory stresses. A highly macroporous scaffold, housed within an alternative transplant site, can support an ideal environment for islet transplantation by providing three-dimensional distribution of islets, while permitting the infiltration of host vasculature. In the present study, we sought to evaluate the synergistic effect of a proangiogenic hydrogel loaded within the void space of a macroporous poly(dimethylsiloxane) (PDMS) scaffold on islet engraftment. The fibrin-based proangiogenic hydrogel tested presents platelet derived growth factor (PDGF-BB), via a fibronectin (FN) fragment containing growth factor and major integrin binding sites in close proximity. The combination of the proangiogenic hydrogel with PDMS scaffolds resulted in a significant decrease in the time to normoglycemia for syngeneic mouse islet transplants. This benefit was associated with an observed increase in competent vessel branching, as well as mature intraislet vessels. Overall, the addition of the proangiogenic factor PDGF-BB, delivered via the FN fragment-functionalized hydrogel, positively influenced the efficiency of engraftment. These characteristics, along with its ease of retrieval, make this combination of a biostable macroporous scaffold and a degradable proangiogenic hydrogel a supportive structure for insulin-producing cells implanted in extrahepatic sites. PMID:23790218

  18. Proangiogenic hydrogels within macroporous scaffolds enhance islet engraftment in an extrahepatic site.

    PubMed

    Brady, Ann-Christina; Martino, Mikaël M; Pedraza, Eileen; Sukert, Steve; Pileggi, Antonello; Ricordi, Camillo; Hubbell, Jeffrey A; Stabler, Cherie L

    2013-12-01

    The transplantation of allogeneic islets in recent clinical trials has shown substantial promise as a therapy for type 1 diabetes; however, long-term insulin independence remains inadequate. This has been largely attributed to the current intravascular, hepatic transplant site, which exposes islets to mechanical and inflammatory stresses. A highly macroporous scaffold, housed within an alternative transplant site, can support an ideal environment for islet transplantation by providing three-dimensional distribution of islets, while permitting the infiltration of host vasculature. In the present study, we sought to evaluate the synergistic effect of a proangiogenic hydrogel loaded within the void space of a macroporous poly(dimethylsiloxane) (PDMS) scaffold on islet engraftment. The fibrin-based proangiogenic hydrogel tested presents platelet derived growth factor (PDGF-BB), via a fibronectin (FN) fragment containing growth factor and major integrin binding sites in close proximity. The combination of the proangiogenic hydrogel with PDMS scaffolds resulted in a significant decrease in the time to normoglycemia for syngeneic mouse islet transplants. This benefit was associated with an observed increase in competent vessel branching, as well as mature intraislet vessels. Overall, the addition of the proangiogenic factor PDGF-BB, delivered via the FN fragment-functionalized hydrogel, positively influenced the efficiency of engraftment. These characteristics, along with its ease of retrieval, make this combination of a biostable macroporous scaffold and a degradable proangiogenic hydrogel a supportive structure for insulin-producing cells implanted in extrahepatic sites. PMID:23790218

  19. Comparison of the Mechanical Properties of Early Leukocyte- and Platelet-Rich Fibrin versus PRGF/Endoret Membranes

    PubMed Central

    Khorshidi, Hooman; Raoofi, Saeed; Bagheri, Rafat; Banihashemi, Hodasadat

    2016-01-01

    Objectives. The mechanical properties of membranes are important factors in the success of treatment and clinical handling. The goal of this study was to compare the mechanical properties of early leukocyte- and platelet-rich fibrin (L-PRF) versus PRGF/Endoret membrane. Materials and Methods. In this experimental study, membranes were obtained from 10 healthy male volunteers. After obtaining 20 cc venous blood from each volunteer, 10 cc was used to prepare early L-PRF (group 1) and the rest was used to get a membrane by PRGF-Endoret system (group 2). Tensile loads were applied to specimens using universal testing machine. Tensile strength, stiffness, and toughness of the two groups of membranes were calculated and compared by paired t-test. Results. The mean tensile strength and toughness were higher in group 1 with a significant difference (P < 0.05). The mean stiffness in group 1 was also higher but not statistically significant (P > 0.05). Conclusions. The results showed that early L-PRF membranes had stronger mechanical properties than membranes produced by PRGF-Endoret system. Early L-PRF membranes might have easier clinical handling and could be a more proper scaffold in periodontal regenerative procedures. The real results of the current L-PRF should be in fact much higher than what is reported here. PMID:26880919

  20. Preparation of hydrophilic poly(lactic acid) tissue engineering scaffold via (PLA)-(PLA-b-PEG)-(PEG) solution casting and thermal-induced surface structural transformation.

    PubMed

    Zhu, Xiaomin; Zhong, Tian; Huang, Ran; Wan, Ajun

    2015-01-01

    Porous poly(lactic acid) (PLA) tissue engineering scaffolds with a hydrophilic surface assembled by polyethylene glycol aggregations were prepared by the solvent casting/particulate leaching method from (PLA)-(PLA-b-PEG)-(PEG) blend solution, where the PLA-b-PEG block polymer serves as an amphiphilic glue between two phases. A thermal recrystallization process was inserted before leaching to induce a phase separation, which subsequently squeezes out PEG to form a hydrophilic shell. Characterizations of XRD and DSC indicated the composition and mixing states of materials. The water contact angle test qualitatively presented the excellent hydrophilicity compared to the pure PLA or PLA-PEG simple blend scaffold. The scanning electron microscope results confirmed the formation of porous structure of [Formula: see text] pore size, with an observable phase separation on the surface. The scaffold was degraded in PBS at [Formula: see text], and the degradation exhibits a three-stage behavior, which evidenced the amphiphilically glued phase separations.

  1. 9 CFR 95.10 - Glue stock; importations permitted subject to restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... disinfection by such method or methods as the Deputy Administrator, Veterinary Services may prescribe unless... permission by the Deputy Administrator, Veterinary Services glue stock may be stored for a temporary period... persons authorized by the Deputy Administrator, Veterinary Services so to do, or without sealing...

  2. 9 CFR 95.10 - Glue stock; importations permitted subject to restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... disinfection by such method or methods as the Deputy Administrator, Veterinary Services may prescribe unless... permission by the Deputy Administrator, Veterinary Services glue stock may be stored for a temporary period... persons authorized by the Deputy Administrator, Veterinary Services so to do, or without sealing...

  3. Use of cyanoacrylate glue to prepare cultured keratinocyte sheets for grafting.

    PubMed

    Meana, A; Iglesias, J; Madrigal, B; Sanchez, J

    1997-01-01

    We describe a method to prepare keratinocyte cultured sheets for grafting based on the use of an organic glue (n-butyl-2-cyanoacrylate). It is a rapid and easy method in which the cultured layers of keratinocytes remain with a surface area similar to the original cultures.

  4. Magnetic Retraction of Bowel by Intraluminal Injectable Cyanoacrylate-Based Magnetic Glue

    PubMed Central

    Brown, Andrew; André, Pascal; Brown, Stuart I.; Florence, Gordon J.; Cuschieri, Alfred

    2013-01-01

    Magnetic retraction offers advantages over physical retraction by graspers because of reduced tissue trauma. The objectives of this study are to investigate a novel method of magnetisation of bowel segments by intraluminal injection of magnetic glue and to demonstrate the feasibility of magnetic retraction of bowel with sufficient force during minimal access surgery. Following an initial materials characterisation study, selected microparticles of stainless steel (SS410-μPs) were mixed with chosen cyanoacrylate glue (Loctite 4014). During intraluminal injection of the magnetic glue using ex vivo porcine colonic segments, a magnetic probe placed at the injected site ensured that the SS410-μPs aggregated during glue polymerisation to form an intraluminal mucosally adherent coagulum. The magnetised colonic segments were retracted by magnetic probes (5 and 10 mm) placed external to the bowel wall. A tensiometer was used to record the retraction force. With an injected volume of 2 mL in a particle concentration of 1 g/mL, this technique produced maximal magnetic retraction forces of 2.24 ± 0.23 N and 5.11 ± 0.34 N (n = 20), with use of 5 and 10 mm probes, respectively. The results indicate that the formation of an intraluminal coagulum based on SS410-μPs and Loctite 4014 produces sufficient magnetic retraction for bowel retraction. PMID:24319684

  5. Transcatheter Embolization of a Large Symptomatic Pelvic Arteriovenous Malformation with Glubran 2 Acrylic Glue

    SciTech Connect

    Gandini, R.; Angelopoulos, G. Konda, D.; Messina, M.; Chiocchi, M.; Perretta, T.; Simonetti, G.

    2008-09-15

    A young patient affected by a pelvic arteriovenous malformation (pAVM) with recurrent episodes of hematuria following exercise, underwent transcatheter embolization using Glubran 2 acrylic glue (GEM, Viareggio, Italy). All branches of the pAVM were successfully occluded. The patient showed prompt resolution of symptoms and persistent occlusion of the pAVM at the 6 month follow-up.

  6. Embolization with Histoacryl Glue of an Anastomotic Pseudoaneurysm following Surgical Repair of Abdominal Aortic Aneurysm

    PubMed Central

    Walid, Ayesha; Ul Haq, Tanveer; Ur Rehman, Zia

    2013-01-01

    We report a 62-year-old female who had surgical repair of abdominal aortic aneurysm with a bifurcated graft 2 years ago. She presented with a distal anastomotic pseudoaneurysm which was successfully embolized with histoacryl glue. Only one such similar case has been reported in the literature so far (Yamagami et al. (2006)). PMID:23476883

  7. Scaffolding Student Participation in Mathematical Practices

    ERIC Educational Resources Information Center

    Moschkovich, Judit N.

    2015-01-01

    The concept of scaffolding can be used to describe various types of adult guidance, in multiple settings, across different time scales. This article clarifies what we mean by scaffolding, considering several questions specifically for scaffolding in mathematics: What theoretical assumptions are framing scaffolding? What is being scaffolded? At…

  8. 49 CFR 214.109 - Scaffolding.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... requirements: (1) Each scaffold and scaffold component, except suspension ropes and guardrail systems, but... least four times the maximum intended load applied or transmitted to that scaffold or scaffold component... guardrail system and the walking/working level. (b) Scaffolds shall not be altered or moved while they...

  9. 49 CFR 214.109 - Scaffolding.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... requirements: (1) Each scaffold and scaffold component, except suspension ropes and guardrail systems, but... least four times the maximum intended load applied or transmitted to that scaffold or scaffold component... guardrail system and the walking/working level. (b) Scaffolds shall not be altered or moved while they...

  10. 49 CFR 214.109 - Scaffolding.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... requirements: (1) Each scaffold and scaffold component, except suspension ropes and guardrail systems, but... least four times the maximum intended load applied or transmitted to that scaffold or scaffold component... guardrail system and the walking/working level. (b) Scaffolds shall not be altered or moved while they...

  11. 49 CFR 214.109 - Scaffolding.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... requirements: (1) Each scaffold and scaffold component, except suspension ropes and guardrail systems, but... least four times the maximum intended load applied or transmitted to that scaffold or scaffold component... guardrail system and the walking/working level. (b) Scaffolds shall not be altered or moved while they...

  12. 49 CFR 214.109 - Scaffolding.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... requirements: (1) Each scaffold and scaffold component, except suspension ropes and guardrail systems, but... least four times the maximum intended load applied or transmitted to that scaffold or scaffold component... guardrail system and the walking/working level. (b) Scaffolds shall not be altered or moved while they...

  13. Fibrin powder turbidity measurement for rapid assessment of antiplasmins.

    PubMed

    Exner, T; Rickard, K A; Kronenberg, H

    1975-11-01

    Fibrinolytic activity was determined from the rate of disappearance of turbidity in a suspension of heat-treated fibrin powder. Using this method for estimating residual fibrinolytic activity in mixtures of serum and plasmin, antiplasmin behaviors of specimens from patients with various clinical disorders were determined after long and short preincubation times. Slow-acting antiplasmins were found to be increased in a variety of conditions among these patients, while immediate acting antiplasmins were generally decreased, compared with those in specimens from a large pool of normal, healthy vounteers. Normal women taking oral contraceptives had consitently high levels of slow antiplasmins. Tests in vitro showed that the antifibrinolytic agents epsilon-aminocaproic acid, Trasylol and soybean trypsin inhibitor act only as fast antiplasmins.

  14. A recently developed bifacial platelet-rich fibrin matrix.

    PubMed

    Lucarelli, E; Beretta, R; Dozza, B; Tazzari, P L; O'Connel, S M; Ricci, F; Pierini, M; Squarzoni, S; Pagliaro, P P; Oprita, E I; Donati, D

    2010-07-01

    Platelet-rich plasma (PRP) is used clinically in liquid or gel form to promote tissue repair. Because of the poor mechanical properties, conventional PRP is often difficult to handle when used in clinical settings and requires secure implantation in a specific site, otherwise when released growth factors could be washed out during an operation. In this study, we analyzed the end product of a recently developed commercially available system (FIBRINET), which is a dense pliable, platelet-rich fibrin matrix (PRFM). We characterized the mechanical properties of PRFM and tested whether PRFM releases growth factors and whether released factors induce the proliferation of mesenchymal stem cells (MSC). Mechanical properties as well as platelet distribution were evaluated in PRFM. PRFM demonstrated robust mechanical properties, with a tear elastic modulus of 937.3 +/- 314.6 kPa, stress at a break of 1476.0 +/- 526.3 kPa, and an elongation at break of 146.3 +/- 33.8 %. PRFM maintained its mechanical properties throughout the testing process. Microscopic observations showed that the platelets were localized on one side of the matrix. Elevated levels of PDGF-AA, PDGF-AB, EGF, VEGF, bFGF and TGF-beta1 were measured in the day 1-conditioned media (CM) of PRFM and growth factor levels decreased thereafter. BMP2 and BMP7 were not detectable. MSC culture media supplemented with 20% PRFM-CM stimulated MSC cell proliferation; at 24 and 48 hours the induction of the proliferation was significantly greater than the induction obtained with media supplemented with 20% foetal bovine serum. The present study shows that the production of a dense, physically robust PRFM made through high-speed centrifugation of intact platelets and fibrin in the absence of exogenous thrombin yields a potential tool for accelerating tissue repair.

  15. Bioresorbable Scaffolds for Atheroregression: Understanding of Transient Scaffolding.

    PubMed

    Kharlamov, Alexander N

    2016-01-01

    This review focuses on the clinical and biological features of the bioresorbable scaffolds in interventional cardiology highlighting scientific achievements and challenges of the transient scaffolding with Absorb BVS. Special attention is granted to the vascular biology pathways which, involved in the resorption of scaffold, artery remodeling and mechanisms of Glagovian atheroregression setting the stage for subsequent clinical applications. Twenty five years ago Glagov described the phenomenon of limited external elastic membrane enlargement in response to an increase in plaque burden. We believe this threshold becomes the target for development of strategies that reverse atherosclerosis, and particularly transient scaffolding has a potential to be a tool to ultimately conquer atherosclerosis. PMID:26818488

  16. THE PATHOGENIC ROLE OF FIBRIN DEPOSITION IN THE GLOMERULAR LESIONS OF TOXEMIA OF PREGNANCY

    PubMed Central

    Vassalli, Pierre; Morris, Robert H.; McCluskey, Robert T.

    1963-01-01

    An immunofluorescent study of renal biopsies from patients with toxemia of pregnancy has been performed. It was found that the glomeruli consistently showed bright staining for fibrin within endothelial cells, as well as occasional deposits along the basement membrane. Gamma globulin was only occasionally demonstrable, generally in the form of irregular deposits along the basement membrane. β1C was absent and albumin was not seen in glomeruli, except sometimes in the form of droplets within epithelial cells. In biopsies from pregnant patients without toxemia only equivocal staining for fibrin was seen. On the basis of these observations and other evidence discussed, it is proposed that the accumulation of fibrin in glomeruli reflects a prolonged state of intravascular clotting in toxemia and that the arrest in glomeruli of some form of circulating fibrin constitutes the basic pathogenic mechanism of the glomerular damage in this disease. PMID:14078004

  17. Batroxobin binds fibrin with higher affinity and promotes clot expansion to a greater extent than thrombin.

    PubMed

    Vu, Trang T; Stafford, Alan R; Leslie, Beverly A; Kim, Paul Y; Fredenburgh, James C; Weitz, Jeffrey I

    2013-06-01

    Batroxobin is a thrombin-like serine protease from the venom of Bothrops atrox moojeni that clots fibrinogen. In contrast to thrombin, which releases fibrinopeptide A and B from the NH2-terminal domains of the Aα- and Bβ-chains of fibrinogen, respectively, batroxobin only releases fibrinopeptide A. Because the mechanism responsible for these differences is unknown, we compared the interactions of batroxobin and thrombin with the predominant γA/γA isoform of fibrin(ogen) and the γA/γ' variant with an extended γ-chain. Thrombin binds to the γ'-chain and forms a higher affinity interaction with γA/γ'-fibrin(ogen) than γA/γA-fibrin(ogen). In contrast, batroxobin binds both fibrin(ogen) isoforms with similar high affinity (Kd values of about 0.5 μM) even though it does not interact with the γ'-chain. The batroxobin-binding sites on fibrin(ogen) only partially overlap with those of thrombin because thrombin attenuates, but does not abrogate, the interaction of γA/γA-fibrinogen with batroxobin. Furthermore, although both thrombin and batroxobin bind to the central E-region of fibrinogen with a Kd value of 2-5 μM, the α(17-51) and Bβ(1-42) regions bind thrombin but not batroxobin. Once bound to fibrin, the capacity of batroxobin to promote fibrin accretion is 18-fold greater than that of thrombin, a finding that may explain the microvascular thrombosis that complicates envenomation by B. atrox moojeni. Therefore, batroxobin binds fibrin(ogen) in a manner distinct from thrombin, which may contribute to its higher affinity interaction, selective fibrinopeptide A release, and prothrombotic properties. PMID:23612970

  18. [APPLICATION OF FISTULA PLUG WITH THE FIBRIN ADHESIVE IN TREATMENT OF RECTAL FISTULAS].

    PubMed

    Aydinova, P R; Aliyev, E A

    2015-05-01

    Results of surgical treatment of 21 patients, suffering high transsphincteric and extrasphincteric rectal fistulas, were studied. In patients of Group I the fistula passage was closed, using fistula plug obturator; and in patients of Group II--by the same, but preprocessed by fibrin adhesive. The fistula aperture germeticity, prophylaxis of rude cicatrices development in operative wound zone, promotion of better fixation of bioplastic material were guaranteed, using fistula plug obturator with preprocessing, using fibrin adhesive. PMID:26419026

  19. Enzymatic mineralization of silk scaffolds.

    PubMed

    Samal, Sangram K; Dash, Mamoni; Declercq, Heidi A; Gheysens, Tom; Dendooven, Jolien; Van Der Voort, Pascal; Cornelissen, Ria; Dubruel, Peter; Kaplan, David L

    2014-07-01

    The present study focuses on the alkaline phosphatase (ALP) mediated formation of apatitic minerals on porous silk fibroin protein (SFP) scaffolds. Porous SFP scaffolds impregnated with different concentrations of ALP are homogeneously mineralized under physiological conditions. The mineral structure is apatite while the structures differ as a function of the ALP concentration. Cellular adhesion, proliferation, and colonization of osteogenic MC3T3 cells improve on the mineralized SFP scaffolds. These findings suggest a simple process to generate mineralized scaffolds that can be used to enhanced bone tissue engineering-related utility. PMID:24610728

  20. A Novel Platelet Concentrate: Titanium-Prepared Platelet-Rich Fibrin

    PubMed Central

    Tunalı, Mustafa; Özdemir, Hakan; Küçükodacı, Zafer; Akman, Serhan; Yaprak, Emre; Toker, Hülya; Fıratlı, Erhan

    2014-01-01

    We developed a new product called titanium-prepared platelet-rich fibrin (T-PRF). The T-PRF method is based on the hypothesis that titanium may be more effective in activating platelets than the silica activators used with glass tubes in Chouckroun's leukocyte- and platelet-rich fibrin (L-PRF) method. In this study, we aimed to define the structural characteristics of T-PRF and compare it with L-PRF. Blood samples were collected from 10 healthy male volunteers. The blood samples were drawn using a syringe. Nine milliliters was transferred to a dry glass tube, and 9 mL was transferred to a titanium tube. Half of each clot (i.e., the blood that was clotted using T-PRF or L-PRF) was processed with a scanning electron microscope (SEM). The other half of each clot was processed for fluorescence microscopy analysis and light microscopy analysis. The T-PRF samples seemed to have a highly organized network with continuous integrity compared to the other L-PRF samples. Histomorphometric analysis showed that T-PRF fibrin network covers larger area than L-PRF fibrin network; also fibrin seemed thicker in the T-PRF samples. This is the first human study to define T-PRF as an autogenous leukocyte- and platelet-rich fibrin product. The platelet activation by titanium seems to offer some high characteristics to T-PRF. PMID:24563860

  1. Fibrin Sealant: The Only Approved Hemostat, Sealant, and Adhesive—a Laboratory and Clinical Perspective

    PubMed Central

    Spotnitz, William D.

    2014-01-01

    Background. Fibrin sealant became the first modern era material approved as a hemostat in the United States in 1998. It is the only agent presently approved as a hemostat, sealant, and adhesive by the Food and Drug Administration (FDA). The product is now supplied as patches in addition to the original liquid formulations. Both laboratory and clinical uses of fibrin sealant continue to grow. The new literature on this material also continues to proliferate rapidly (approximately 200 papers/year). Methods. An overview of current fibrin sealant products and their approved uses and a comprehensive PubMed based review of the recent literature (February 2012, through March 2013) on the laboratory and clinical use of fibrin sealant are provided. Product information is organized into sections based on a classification system for commercially available materials. Publications are presented in sections based on both laboratory research and clinical topics are listed in order of decreasing frequency. Results. Fibrin sealant remains useful hemostat, sealant, and adhesive. New formulations and applications continue to be developed. Conclusions. This agent remains clinically important with the recent introduction of new commercially available products. Fibrin sealant has multiple new uses that should result in further improvements in patient care. PMID:24729902

  2. Fibrin Sealant: The Only Approved Hemostat, Sealant, and Adhesive-a Laboratory and Clinical Perspective.

    PubMed

    Spotnitz, William D

    2014-01-01

    Background. Fibrin sealant became the first modern era material approved as a hemostat in the United States in 1998. It is the only agent presently approved as a hemostat, sealant, and adhesive by the Food and Drug Administration (FDA). The product is now supplied as patches in addition to the original liquid formulations. Both laboratory and clinical uses of fibrin sealant continue to grow. The new literature on this material also continues to proliferate rapidly (approximately 200 papers/year). Methods. An overview of current fibrin sealant products and their approved uses and a comprehensive PubMed based review of the recent literature (February 2012, through March 2013) on the laboratory and clinical use of fibrin sealant are provided. Product information is organized into sections based on a classification system for commercially available materials. Publications are presented in sections based on both laboratory research and clinical topics are listed in order of decreasing frequency. Results. Fibrin sealant remains useful hemostat, sealant, and adhesive. New formulations and applications continue to be developed. Conclusions. This agent remains clinically important with the recent introduction of new commercially available products. Fibrin sealant has multiple new uses that should result in further improvements in patient care. PMID:24729902

  3. Inhibition of thrombin generation in plasma by fibrin formation (Antithrombin I).

    PubMed

    de Bosch, N B; Mosesson, M W; Ruiz-Sáez, A; Echenagucia, M; Rodriguez-Lemoin, A

    2002-08-01

    The adsorption of thrombin to fibrin during clotting defines "Antithrombin I" activity. We confirmed that thrombin generation in afibrinogenemic or in Reptilase defibrinated normal plasma was higher than in normal plasma. Repletion of these fibrinogen-deficient plasmas with fibrinogen 1 (gamma A/gamma A), whose fibrin has two "low affinity" non-substrate thrombin binding sites, resulted in moderately reduced thrombin generation by 29-37%. Repletion with fibrinogen 2 (gamma'/gamma A), which in addition to low affinity thrombin-binding sites in fibrin, has a "high affinity" non-substrate thrombin binding site in the carboxy-terminal region of its gamma' chain, was even more effective and reduced thrombin generation by 57-67%. Adding peptides that compete for thrombin binding to fibrin [S-Hir53-64 (hirugen) or gamma'414-427] caused a transient delay in the onset of otherwise robust thrombin generation, indicating that fibrin formation is necessary for full expression of Antithrombin I activity. Considered together, 1) the increased thrombin generation in afibrinogenemic or fibrinogen-depleted normal plasma that is mitigated by fibrinogen replacement; 2) evidence that prothrombin activation is increased in afibrinogenemia and normalized by fibrinogen replacement; 3) the severe thrombophilia that is associated with defective thrombin-binding in dysfibrinogenemias Naples I and New York I, and 4) the association of afibrinogenemia or hypofibrinogenemia with venous or arterial thromboembolism, indicate that Antithrombin I (fibrin) modulates thromboembolic potential by inhibiting thrombin generation in blood.

  4. Endothelial Cells Organize Fibrin Clots into Structures That Are More Resistant to Lysis

    NASA Astrophysics Data System (ADS)

    Gray Jerome, W.; Handt, Stefan; Hantgan, Roy R.

    2005-06-01

    Acute myocardial infarction is a major cause of death and disability in the United States. Introducing thrombolytic agents into the clot to dissolve occlusive coronary artery thrombi is one method of treatment. However, despite advances in our knowledge of thrombosis and thrombolysis, survival rates following thrombolytic therapy have not improved substantially. This failure highlights the need for further study of the factors mediating clot stabilization. Using laser scanning confocal microscopy of clots formed from fluorescein-labeled fibrinogen, we investigated what effect binding of fibrin to the endothelial surface has on clot structure and resistance to lysis. Fluorescent fibrin clots were produced over human umbilical vein endothelial cells (HUVEC) and the clot structure analyzed. In the presence of HUVEC, fibrin near the endothelial surface was more organized and occurred in tighter bundles compared to fibrin just 50 [mu]m above. The HUVEC influence on fibrin architecture was blocked by inhibitory concentrations of antibodies to [alpha]V or [beta]3 integrin subunits. The regions of the clots associated with endothelial cells were more resistant to lysis than the more homogenous regions distal to endothelium. Thus, our data show that binding of fibrin to integrins on endothelial surfaces produces clots that are more resistant to lysis.

  5. Instruction, Cognitive Scaffolding, and Motivational Scaffolding in Writing Center Tutoring

    ERIC Educational Resources Information Center

    Mackiewicz, Jo; Thompson, Isabelle

    2014-01-01

    In this study, we quantitatively analyze the discourse of experienced writing center tutors in 10 highly satisfactory conferences. Specifically, we analyze tutors' instruction, cognitive scaffolding, and motivational scaffolding, all tutoring strategies identified in prior research from other disciplines as educationally effective. We find…

  6. PEP_scaffolder: using (homologous) proteins to scaffold genomes

    PubMed Central

    Zhu, Bai-Han; Song, Ying-Nan; Xue, Wei; Xu, Gui-Cai; Xiao, Jun; Sun, Ming-Yuan; Sun, Xiao-Wen; Li, Jiong-Tang

    2016-01-01

    Motivation: Recovering the gene structures is one of the important goals of genome assembly. In low-quality assemblies, and even some high-quality assemblies, certain gene regions are still incomplete; thus, novel scaffolding approaches are required to complete gene regions. Results: We developed an efficient and fast genome scaffolding method called PEP_scaffolder, using proteins to scaffold genomes. The pipeline aims to recover protein-coding gene structures. We tested the method on human contigs; using human UniProt proteins as guides, the improvement on N50 size was 17% increase with an accuracy of ∼97%. PEP_scaffolder improved the proportion of fully covered proteins among all proteins, which was close to the proportion in the finished genome. The method provided a high accuracy of 91% using orthologs of distant species. Tested on simulated fly contigs, PEP_scaffolder outperformed other scaffolders, with the shortest running time and the highest accuracy. Availability and Implementation: The software is freely available at http://www.fishbrowser.org/software/PEP_scaffolder/ Contact: lijt@cafs.ac.cn Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27334475

  7. Novel Antibacterial Nanofibrous PLLA Scaffolds

    PubMed Central

    Feng, Kai; Sun, Hongli; Bradley, Mark A.; Dupler, Ellen J.; Giannobile, William V.; Ma, Peter X.

    2010-01-01

    In order to achieve high local bioactivity and low systemic side effects of antibiotics in the treatment of dental, periodontal and bone infections, a localized and temporally controlled delivery system is crucial. In this study, a three-dimensional (3D) porous tissue engineering scaffold was developed with the ability to release antibiotics in a controlled fashion for long-term inhibition of bacterial growth. The highly soluble antibiotic drug, Doxycycline (DOXY), was successfully incorporated into PLGA nanospheres using a modified water-in-oil-in-oil (w/o/o) emulsion method. The PLGA nanospheres (NS) were then incorporated into prefabricated nanofibrous PLLA scaffolds with a well interconnected macroporous structure. The release kinetics of DOXY from four different PLGA NS formulations on a PLLA scaffold was investigated. DOXY could be released from the NS-scaffolds in a locally and temporally controlled manner. The DOXY release is controlled by DOXY diffusion out of the NS and is strongly dependent upon the physical and chemical properties of the PLGA. While PLGA50-6.5K, PLGA50-64K, and PLGA75-113K NS-scaffolds discharge DOXY rapidly with a high initial burst release, PLGA85-142K NS-scaffold can extend the release of DOXY to longer than 6 weeks with a low initial burst release. Compared to NS alone, the NS incorporated on a 3-D scaffold had significantly reduced the initial burst release. In vitro antibacterial tests of PLGA85 NS-scaffold demonstrated its ability to inhibit common bacterial growth (S.aureus and E.coli) for a prolonged duration. The successful incorporation of DOXY onto 3-D scaffolds and its controlled release from scaffolds extends the usage of nano-fibrous scaffolds from the delivery of large molecules such as growth factors to the delivery of small hydrophilic drugs, allowing for a broader application and a more complex tissue engineering strategy. PMID:20570700

  8. The use of fibrin sealant after total thyroidectomy for benign disease obviates the need for routine drainage. Results of a randomized controlled trial

    PubMed Central

    Sözen, S; Topuz, Ö; Tükenmez, M; Keçeli, M

    2011-01-01

    Background: Drains are usually left after thyroid surgery to prevent formation of hematoma and seroma in the thyroid bed. This prospective randomized clinical trial was conducted to evaluate the necessity of drainage after total thyroidectomy for benign thyroidal disorders. Methods: The patients were assigned randomly into two groups (group 1: with suction drain, group 2: fibrin glue). In the study, operating time, postoperative pain, the total amount of intramuscular analgesic administration, hospital stay, complications (such as wound infection, seroma, bleeding, hematoma, recurrent laryngeal nerve palsy or hypoparathyroidism), were recorded. Results: The drained group (group 1) consisted of 2 men and 48 women with a mean age of 47.76±11.22 years. The nondrained (plus fibrin sealant)( group 2) (comprised of 10 men and 40 women with a mean age of 44.72±11.32 years. There was no significant difference in the gender, age, hormonal status and histopathological results of the patients between the two groups (P=0.18, P=0.36, P=0.28 and P=0.40, respectively). The operations performed were total thyroidectomy in all patients. Twenty-five patients (50%) in the non-drained group did not need intramuscular analgesic, whereas 15 patients (30%) did not in the drained group (P=0.01). In addition, the mean amount of intramuscular analgesic requirement was significantly less in the non-drained group than in the drained group (P=0.02). The complication rates were similar between the two groups. One case of hematoma (2%), two cases of seroma (4%) and three cases of transient hypoparathyroidism (6%) occurred in the non-drained group, whereas one case of hematoma (2%), two cases of seroma (4%), two cases of wound infections (4%) and two cases of transient hypoparathyroidism (4%) occurred in the drained group (P=0.69). No patient needed surgical revision or re-operation for any complication and all complications were successfully managed conservatively. Conclusion: Routine drainage

  9. Three-dimensional visualization and quantitation of fibrin in solid tumors by confocal laser scanning microscopy.

    PubMed

    Biggerstaff, J; Amirkhosravi, A; Francis, J L

    1997-10-01

    Fibrin forms part of the stroma essential for growth of solid tumors. Anticoagulants reduce primary tumor growth and tumor metastasis in murine and some human tumors. These effects may be partly mediated by reduction of intra-tumor fibrin, although there are no quantitative data to support this hypothesis. We therefore evaluated the effect of warfarin on fibrin deposition in a subcutaneously (s.c.) implanted murine tumor using confocal laser scanning microscopy (CLSM). AJ mice received no treatment (n = 6) or sodium warfarin (3.5 mg/L in drinking water, n = 5). All animals received 2 x 10(6) syngeneic Neuro2a neuroblastoma cells s.c. After 14 days, primary tumors were excised and placed in liquid nitrogen. Warfarin treatment resulted in a small, but significant (P < 0.05), decrease in wet tumor weight. Frozen sections (20 microns) were incubated with goat anti-mouse fibrin(ogen) or normal goat serum (isotypic control) and stained with FITC-conjugated rabbit anti-goat antibody. Using a Multiprobe 2001 CLSM (Molecular Dynamics, Sunnyvale, CA), 20 serial optical sections were taken from five, randomly chosen, high power fields (60x objective) for each slide. A threshold excluded all fluorescence except that from structural components within the tumor stroma (fibrin). The volume of fibrin in each section series was determined, and the percentage of tumor volume occupied by fibrin calculated. Intra- and inter-assay variation were assessed on serial frozen tumor sections from an untreated animal. The percentage fibrin volume was not significantly different among or within experiments, indicating that the procedure was reproducible. In controls, the median (range) volume occupied by fibrin was 8.1% (2.4-22.3%), whereas in anticoagulated animals, this was reduced to 3.7% (0.4-14.0%; P < 0.001). This is the first quantitative demonstration that warfarin reduces fibrin deposition in solid tumors. We conclude that three-dimensional CLSM is useful for the quantitation of

  10. Three-dimensional visualization and quantitation of fibrin in solid tumors by confocal laser scanning microscopy.

    PubMed

    Biggerstaff, J; Amirkhosravi, A; Francis, J L

    1997-10-01

    Fibrin forms part of the stroma essential for growth of solid tumors. Anticoagulants reduce primary tumor growth and tumor metastasis in murine and some human tumors. These effects may be partly mediated by reduction of intra-tumor fibrin, although there are no quantitative data to support this hypothesis. We therefore evaluated the effect of warfarin on fibrin deposition in a subcutaneously (s.c.) implanted murine tumor using confocal laser scanning microscopy (CLSM). AJ mice received no treatment (n = 6) or sodium warfarin (3.5 mg/L in drinking water, n = 5). All animals received 2 x 10(6) syngeneic Neuro2a neuroblastoma cells s.c. After 14 days, primary tumors were excised and placed in liquid nitrogen. Warfarin treatment resulted in a small, but significant (P < 0.05), decrease in wet tumor weight. Frozen sections (20 microns) were incubated with goat anti-mouse fibrin(ogen) or normal goat serum (isotypic control) and stained with FITC-conjugated rabbit anti-goat antibody. Using a Multiprobe 2001 CLSM (Molecular Dynamics, Sunnyvale, CA), 20 serial optical sections were taken from five, randomly chosen, high power fields (60x objective) for each slide. A threshold excluded all fluorescence except that from structural components within the tumor stroma (fibrin). The volume of fibrin in each section series was determined, and the percentage of tumor volume occupied by fibrin calculated. Intra- and inter-assay variation were assessed on serial frozen tumor sections from an untreated animal. The percentage fibrin volume was not significantly different among or within experiments, indicating that the procedure was reproducible. In controls, the median (range) volume occupied by fibrin was 8.1% (2.4-22.3%), whereas in anticoagulated animals, this was reduced to 3.7% (0.4-14.0%; P < 0.001). This is the first quantitative demonstration that warfarin reduces fibrin deposition in solid tumors. We conclude that three-dimensional CLSM is useful for the quantitation of

  11. Platelet-rich plasma and fibrin as delivery systems for recombinant human bone morphogenetic protein-2.

    PubMed

    Jung, Ronald E; Schmoekel, Hugo G; Zwahlen, Roger; Kokovic, Vladimir; Hammerle, Christoph H F; Weber, Franz E

    2005-12-01

    The aim of the present study was (1) to test whether or not platelet-rich plasma (PRP) or commercially available fibrin can increase bone regeneration compared with non-treated defects and (2) to test whether or not PRP or fibrin increases bone regeneration when used as a delivery system for recombinant human bone morphogenetic protein-2 (rhBMP-2). In 16 New Zealand White rabbits, four evenly distributed 6 mm diameter defects were drilled into the calvarial bone. The following five treatment modalities were randomly allocated to all 64 defects: (0) untreated control, (1) fibrin alone, (2) PRP alone, (3) fibrin with 15 microg rhBMP-2 and (4) PRP with 15 microg rhBMP-2. For the fibrin gels and the PRP containing rhBMP-2, the 15 microg rhBMP-2 was incorporated by precipitation within the matrices before their gelation. After 4 weeks, the animals were sacrificed and the calvarial bones were removed for histological preparation. The area fraction of newly formed bone was determined in vertical sections from the middle of the defect by applying histomorphometrical analysis. A mean area fraction of newly formed bone was found within the former defect of 23.4% (+/-13.5%) in the control sites, of 28.4% (+/-17.4%) in the fibrin sites and of 34.5% (+/-17.4%) in the PRP sites. The statistical analysis revealed no significant difference in bone formation between the three groups (ANOVA). Addition of 15 microg rhBMP-2 in the fibrin gel (59.9+/-20.3%) and the PRP gels (63.1+/-25.3%) increased bone formation significantly. No significant difference was observed between sites, where PRP or fibrin has been used as a delivery system for rhBMP-2 (ANOVA). In conclusion, the application of fibrin gels or PRP gels to bone defects is not superior to leaving the defect untreated. Regarding the amount of bone formation, the application of 15 microg rhBMP-2 in bone defects enhances the healing significantly at 4 weeks. In this animal model, commercially available fibrin and autologous PRP

  12. Critical Speed of The Glass Glue Machine's Creep and Influence Factors Analysis

    NASA Astrophysics Data System (ADS)

    Yang, Jianxi; Huang, Jian; Wang, Liying; Shi, Jintai

    When automatic glass glue machine works, two questions of the machine starting vibrating and stick-slip motion are existing. These problems should be solved. According to these questions, a glue machine's model for studying stick-slip is established. Based on the dynamics system describing of the model, mathematical expression is presented. The creep critical speed expression is constructed referring to existing research achievement and a new conclusion is found. The influencing factors of stiffness, dampness, mass, velocity, difference of static and kinetic coefficient of friction are analyzed through Matlab simulation. Research shows that reasonable choice of influence parameters can improve the creep phenomenon. These all supply the theory evidence for improving the machine's motion stability.

  13. Development of silicon photomultipliers and their applications to GlueX calorimetry

    NASA Astrophysics Data System (ADS)

    Smith, Elton S.

    2016-07-01

    The GlueX experiment is a photoproduction experiment in Hall D at Jefferson Lab that is being commissioned for use with the new 12 GeV accelerator. The purpose of the experiment is to search for Hybrid mesons, which are mesons with quark and gluon degrees of freedom. The barrel calorimeter of GlueX is instrumented with 4000 large-area (1.2 × 1.2 cm2) silicon photomultipliers (SiPMs). These photon sensors have properties similar to vacuum photomultipliers, but are unaffected by high magnetic fields. In our experiment they operate in magnetic fields exceeding 1T. After extensive tests with a variety of sensors, we chose the S12045(X) custom SiPM arrays manufactured by Hamamatsu Corporation, also known as multi-pixel photon counters (MPPCs). We will give an overview of this new technology as well as the experience gained during two commissioning periods with beam.

  14. Uncertainty in urban stormwater quality modelling: the effect of acceptability threshold in the GLUE methodology.

    PubMed

    Freni, Gabriele; Mannina, Giorgio; Viviani, Gaspare

    2008-04-01

    Uncertainty analysis in integrated urban drainage modelling is of growing importance in the field of water quality. However, only few studies deal with uncertainty quantification in urban drainage modelling; furthermore, the few existing studies mainly focus on quantitative sewer flow modelling rather than uncertainty in water quality aspects. In this context, the generalised likelihood uncertainty estimation (GLUE) methodology was applied for the evaluation of the uncertainty of an integrated urban drainage model and some of its subjective hypotheses have been explored. More specifically, the influence of the subjective choice of the acceptability threshold has been detected in order to gain insights regarding its effect on the model results. The model has been applied to the Savena case study (Bologna, Italy) where water quality and quantity data were available. The model results show a strong influence of the acceptability threshold selection and confirm the importance of modeller's experience in the application of GLUE uncertainty analysis.

  15. Detection of bone glue treatment as a major source of contamination in ancient DNA analyses.

    PubMed

    Nicholson, Graeme J; Tomiuk, Jürgen; Czarnetzki, Alfred; Bachmann, Lutz; Pusch, Carsten M

    2002-06-01

    Paleogenetic investigations of ancient DNA extracted from fossil material is for many reasons susceptible to falsification by the presence of more recent contamination from several sources. Gelatine-based bone glue that has been used extensively for nearly two centuries by curators to preserve hard tissues contributes nonauthentic DNA to paleontological material. This fact has been frequently neglected and is barely mentioned in the literature. Now paleogeneticists, curators, and conservators are faced with the problem that treatment of samples with adhesives and consolidants for conservatory purposes has seldom been recorded. Here, we show that racemization of amino acids, and in particular serine, is an excellent indicator for the treatment of paleontological samples with glue.

  16. Study of nano imprinting using soft lithography on Krafty glue and PVDF polymer thin films

    SciTech Connect

    Sankar, M. S. Ravi Gangineni, Ramesh Babu

    2014-04-24

    The present work reveals soft lithography strategy based on self assembly and replica molding for carrying out micro and nanofabrication. It provides a convenient, effective and very low cost method for the formation and manufacturing of micro and nano structures. Al-layer of compact disc (sony CD-R) used as a stamp with patterned relief structures to generate patterns and structures with pattern size of 100nm height, 1.7 μm wide. In literature, PDMS (Polydimethylsiloxane) solution is widely used to get negative copy of the Al-layer. In this work, we have used inexpensive white glue (Polyvinylacetate + water), 15gm (□5) and PVDF (Polyvinylidene difluoride) spin coated films and successfully transferred the nano patterns of Al layer on to white glue and PVDF films.

  17. The Research of Improving the Particleboard Glue Dosing Process Based on TRIZ Analysis

    NASA Astrophysics Data System (ADS)

    Yu, Huiling; Fan, Delin; Zhang, Yizhuo

    This research creates a design methodology by synthesizing the Theory of Inventive Problem Solving (TRIZ) and cascade control based on Smith predictor. The particleboard glue supplying and dosing system case study defines the problem and the solution using the methodology proposed in the paper. Status difference existing in the gluing dosing process of particleboard production usually causes gluing volume inaccurately. In order to solve the problem above, we applied the TRIZ technical contradiction and inventive principle to improve the key process of particleboard production. The improving method mapped inaccurate problem to TRIZ technical contradiction, the prior action proposed Smith predictor as the control algorithm in the glue dosing system. This research examines the usefulness of a TRIZ based problem-solving process designed to improve the problem-solving ability of users in addressing difficult or reoccurring problems and also testify TRIZ is practicality and validity. Several suggestions are presented on how to approach this problem.

  18. A hospital cost analysis of a fibrin sealant patch in soft tissue and hepatic surgical bleeding

    PubMed Central

    Corral, Mitra; Ferko, Nicole; Hogan, Andrew; Hollmann, Sarah S; Gangoli, Gaurav; Jamous, Nadine; Batiller, Jonathan; Kocharian, Richard

    2016-01-01

    Background Despite hemostat use, uncontrolled surgical bleeding is prevalent. Drawbacks of current hemostats include limitations with efficacy on first attempt and suboptimal ease-of-use. Evarrest® is a novel fibrin sealant patch that has demonstrated high hemostatic efficacy compared with standard of care across bleeding severities. The objective of this study was to conduct a hospital cost analysis of the fibrin sealant patch versus standard of care in soft tissue and hepatic surgical bleeding. Methods The analysis quantified the 30-day costs of each comparator from a hospital perspective. Published US unit costs were applied to resource use (ie, initial treatment, retreatment, operating time, hospitalization, transfusion, and ventilator) reported in four trials. A “surgical” analysis included resources clinically related to the hemostatic benefit of the fibrin sealant patch, whereas a “hospital” analysis included all resources reported in the trials. An exploratory subgroup analysis focused solely on coagulopathic patients defined by abnormal blood test results. Results The surgical analysis predicted cost savings of $54 per patient with the fibrin sealant patch compared with standard of care (net cost impact: −$54 per patient; sensitivity range: −$1,320 to $1,213). The hospital analysis predicted further cost savings with the fibrin sealant patch (net cost impact of −$2,846 per patient; sensitivity range: −$1,483 to −$5,575). Subgroup analyses suggest that the fibrin sealant patch may provide dramatic cost savings in the coagulopathic subgroup of $3,233 (surgical) and $9,287 (hospital) per patient. Results were most sensitive to operating time and product units. Conclusion In soft tissue and hepatic problematic surgical bleeding, the fibrin sealant patch may result in important hospital cost savings. PMID:27703386

  19. A safe and efficient method to retrieve mesenchymal stem cells from three-dimensional fibrin gels.

    PubMed

    Carrion, Bita; Janson, Isaac A; Kong, Yen P; Putnam, Andrew J

    2014-03-01

    Mesenchymal stem cells (MSCs) display multipotent characteristics that make them ideal for potential therapeutic applications. MSCs are typically cultured as monolayers on tissue culture plastic, but there is increasing evidence suggesting that they may lose their multipotency over time in vitro and eventually cease to retain any resemblance to in vivo resident MSCs. Three-dimensional (3D) culture systems that more closely recapitulate the physiological environment of MSCs and other cell types are increasingly explored for their capacity to support and maintain the cell phenotypes. In much of our own work, we have utilized fibrin, a natural protein-based material that serves as the provisional extracellular matrix during wound healing. Fibrin has proven to be useful in numerous tissue engineering applications and has been used clinically as a hemostatic material. Its rapid self-assembly driven by thrombin-mediated alteration of fibrinogen makes fibrin an attractive 3D substrate, in which cells can adhere, spread, proliferate, and undergo complex morphogenetic programs. However, there is a significant need for simple cost-effective methods to safely retrieve cells encapsulated within fibrin hydrogels to perform additional analyses or use the cells for therapy. Here, we present a safe and efficient protocol for the isolation of MSCs from 3D fibrin gels. The key ingredient of our successful extraction method is nattokinase, a serine protease of the subtilisin family that has a strong fibrinolytic activity. Our data show that MSCs recovered from 3D fibrin gels using nattokinase are not only viable but also retain their proliferative and multilineage potentials. Demonstrated for MSCs, this method can be readily adapted to retrieve any other cell type from 3D fibrin gel constructs for various applications, including expansion, bioassays, and in vivo implantation.

  20. The influence of type 2 diabetes on fibrin clot properties in patients with coronary artery disease.

    PubMed

    Neergaard-Petersen, S; Hvas, A-M; Kristensen, S D; Grove, E L; Larsen, S B; Phoenix, F; Kurdee, Z; Grant, P J; Ajjan, R A

    2014-12-01

    Type 2 diabetes mellitus (T2DM) increases the risk of coronary thrombosis and both conditions are associated with altered fibrin clot properties. However, the influence of T2DM on fibrin clot properties in patients with coronary artery disease (CAD) remains unclear. We aimed to investigate the influence of T2DM on fibrin clot properties in patients with CAD. Fibrin clot structure and fibrinolysis were investigated in 581 CAD patients (148 with T2DM) using turbidimetric assays, confocal and scanning electron microscopy. Clots made from plasma and plasma-purified fibrinogen were studied, and plasma levels of inflammatory markers were analysed. T2DM patients had increased clot maximum absorbance compared with non-diabetic patients (0.36 ± 0.1 vs 0.33 ± 0.1 au; p=0.01), displayed longer lysis time (804 [618;1002] vs 750 [624;906] seconds; p=0.03) and showed more compact fibrin structure assessed by confocal and electron microscopy. Fibrinogen levels were elevated in T2DM (p< 0.001), but clots made from purified fibrinogen showed no differences in fibrin properties in the two populations. Adjusting for fibrinogen levels, T2DM was associated with C-reactive protein and complement C3 plasma levels, with the former correlating with clot maximum absorbance (r=0.24, p< 0.0001) and the latter with lysis time (r=0.30, p< 0.0001). Independent of fibrinogen levels, females had more compact clots with prolonged lysis time compared with males (all p-values< 0.001). In conclusion, T2DM is associated with prothrombotic changes in fibrin clot properties in patients with CAD. This is related to quantitative rather than qualitative changes in fibrinogen with a possible role for inflammatory proteins. PMID:25187394

  1. A Safe and Efficient Method to Retrieve Mesenchymal Stem Cells from Three-Dimensional Fibrin Gels

    PubMed Central

    Carrion, Bita; Janson, Isaac A.; Kong, Yen P.

    2014-01-01

    Mesenchymal stem cells (MSCs) display multipotent characteristics that make them ideal for potential therapeutic applications. MSCs are typically cultured as monolayers on tissue culture plastic, but there is increasing evidence suggesting that they may lose their multipotency over time in vitro and eventually cease to retain any resemblance to in vivo resident MSCs. Three-dimensional (3D) culture systems that more closely recapitulate the physiological environment of MSCs and other cell types are increasingly explored for their capacity to support and maintain the cell phenotypes. In much of our own work, we have utilized fibrin, a natural protein-based material that serves as the provisional extracellular matrix during wound healing. Fibrin has proven to be useful in numerous tissue engineering applications and has been used clinically as a hemostatic material. Its rapid self-assembly driven by thrombin-mediated alteration of fibrinogen makes fibrin an attractive 3D substrate, in which cells can adhere, spread, proliferate, and undergo complex morphogenetic programs. However, there is a significant need for simple cost-effective methods to safely retrieve cells encapsulated within fibrin hydrogels to perform additional analyses or use the cells for therapy. Here, we present a safe and efficient protocol for the isolation of MSCs from 3D fibrin gels. The key ingredient of our successful extraction method is nattokinase, a serine protease of the subtilisin family that has a strong fibrinolytic activity. Our data show that MSCs recovered from 3D fibrin gels using nattokinase are not only viable but also retain their proliferative and multilineage potentials. Demonstrated for MSCs, this method can be readily adapted to retrieve any other cell type from 3D fibrin gel constructs for various applications, including expansion, bioassays, and in vivo implantation. PMID:23808842

  2. The scaffold tree: an efficient navigation in the scaffold universe.

    PubMed

    Ertl, Peter; Schuffenhauer, Ansgar; Renner, Steffen

    2011-01-01

    The Scaffold Tree algorithm (J Chem Inf Model 47:47-58, 2007) allows to organize large molecular data sets by arranging sets of molecules into a unique tree hierarchy based on their scaffolds, with scaffolds forming leaf nodes of such tree. The hierarchy is created by iterative removal of rings from more complex scaffolds using chemically meaningful set of rules, until a single, root ring is obtained. The classification is deterministic, data set independent, and scales linearly with the number of compounds included in the data set. In this review we summarize the basic principles of the Scaffold Tree methodology and review its applications, which appeared in recent medicinal chemistry literature, including the use of Scaffold Trees for visualization of large chemical data sets, compound clustering, and the identification of novel bioactive molecules. References to several computer programs, including also free tools available on the Internet, allowing to perform classification and visualization of molecules based on their scaffolds are also provided. PMID:20838972

  3. Spinal cord organotypic slice cultures for the study of regenerating motor axon interactions with 3D scaffolds.

    PubMed

    Gerardo-Nava, Jose; Hodde, Dorothee; Katona, Istvan; Bozkurt, Ahmet; Grehl, Torsten; Steinbusch, Harry W M; Weis, Joachim; Brook, Gary A

    2014-05-01

    Numerous in-vitro techniques exist for investigating the influence of 3D substrate topography on sensory axon growth. However, simple and cost-effective methods for studying post-natal motor axon interactions with such substrates are lacking. Here, spinal cord organotypic slice cultures (OSC) from post-natal day 7-9 rat pups were presented with spinal nerve roots, or blocks of fibrin hydrogel or 3D microporous collagen scaffolds to investigate motor axon-substrate interactions. By 7-14 days, axons from motor neuronal pools extended into the explanted nerve roots, growing along Schwann cell processes and demonstrating a full range of axon-Schwann cell interactions, from simple ensheathment to concentric wrapping by Schwann cell processes and the formation of compact myelin within a basal lamina sheath. Extensive motor axon regeneration and all stages of axon-Schwann interactions were also supported within the longitudinally orientated microporous framework of the 3D collagen scaffold. In stark contrast, the simple fibrin hydrogel only supported axon growth and cell migration over its surface. The relative ease of demonstrating such motor axon regeneration through the microporous 3D framework by immunofluorescence, two-photon microscopy and transmission electron microscopy strongly supports the adoption of this technique for assaying the influence of substrate topography and functionalization in regenerative bioengineering.

  4. A drift detector system with anode and cathode readout in the GlueX experiment

    SciTech Connect

    Berdnikov, V V; Somov, S V; Pentchev, L; Zihlmann, B

    2015-01-01

    A drift detector system designed to detect charged particle tracks in the GlueX experiment dedicated to study the nature of confinement is described. The key design features of the drift chambers associated with the requirement of a minimum material budget in the path of secondary particles are presented. The spatial resolution and the detection efficiency have been measured with cosmic rays using the automatic data acquisition system.

  5. Percutaneous Cyanoacrylate Glue Injection into the Renal Pseudoaneurysm to Control Intractable Hematuria After Percutaneous Nephrolithotomy

    SciTech Connect

    Lal, Anupam Kumar, Ajay; Prakash, Mahesh; Singhal, Manphool; Agarwal, Mayank Mohan; Sarkar, Debansu; Khandelwal, Niranjan

    2009-07-15

    We report a case of a 43-year-old man who developed intractable hematuria after percutaneous nephrolithotomy. Angiography detected a pseudoaneurysm arising from the lower polar artery; however, embolization could not be performed because of unfavorable vascular anatomy. A percutaneous thrombin injection under ultrasound guidance initially controlled the bleeding, but hematuria subsequently recurred as a result of recanalization of the aneurysm. The case was successfully managed with ultrasound- and fluoroscopic-guided direct injection of cyanoacrylate glue into the pseudoaneurysm.

  6. The impact of UVB radiation on the glycoprotein glue of orb-weaving spider capture thread.

    PubMed

    Stellwagen, Sarah D; Opell, Brent D; Clouse, Mary E

    2015-09-01

    Many spider orb-webs are exposed to sunlight and the potentially damaging effects of ultraviolet B (UVB) radiation. We examined the effect of UVB on the viscoelastic glycoprotein core of glue droplets deposited on the prey capture threads of these webs, hypothesizing that webs built by species that occupy sunny habitats are less susceptible to UVB damage than are webs built by species that prefer shaded forest habitats or by nocturnal species. Threads were tested shortly after being collected in the early morning and after being exposed to UVB energy equivalent to a day of summer sun and three times this amount. Droplets kept in a dark chamber allowed us to evaluate post-production changes. Droplet volume was unaffected by treatments, indicating that UVB did not damage the hygroscopic compounds in the aqueous layer that covers droplets. UVB exposure did not affect energies of droplet extension for species from exposed and partially to mostly shaded habitats (Argiope aurantia, Leucauge venusta and Verrucosa arenata). However, UVB exposure reduced the energy of droplet extension in Micrathena gracilis from shaded forests and Neoscona crucifera, which forages at night. Only in L. venusta did the energy of droplet extension increase after the dark treatment, suggesting endogenous molecular alignment. This study adds UVB irradiation to the list of factors (humidity, temperature and strain rate) known to affect the performance of spider glycoprotein glue, factors that must be more fully understood if adhesives that mimic spider glycoprotein glue are to be produced. PMID:26333924

  7. Lattice study of quark and glue momenta and angular momenta in the nucleon

    NASA Astrophysics Data System (ADS)

    Deka, M.; Doi, T.; Yang, Y. B.; Chakraborty, B.; Dong, S. J.; Draper, T.; Glatzmaier, M.; Gong, M.; Lin, H. W.; Liu, K. F.; Mankame, D.; Mathur, N.; Streuer, T.; χ QCD Collaboration

    2015-01-01

    We report a complete calculation of the quark and glue momenta and angular momenta in the proton. These include the quark contributions from both the connected and disconnected insertions. The quark disconnected insertion loops are computed with Z4 noise, and the signal-to-noise ratio is improved with unbiased subtractions. The glue operator is comprised of gauge-field tensors constructed from the overlap operator. The calculation is carried out on a 1 63×24 quenched lattice at β =6.0 for Wilson fermions with κ =0.154 , 0.155, and 0.1555, which correspond to pion masses at 650, 538, and 478 MeV, respectively. The chirally extrapolated u and d quark momentum/angular momentum fraction is found to be 0.64 (5 )/0.70 (5 ), the strange momentum/angular momentum fraction is 0.024 (6 )/0.023 (7 ), and that of the glue is 0.33 (6 )/0.28 (8 ). The previous study of quark spin on the same lattice revealed that it carries a fraction of 0.25(12) of proton spin. The orbital angular momenta of the quarks are then obtained from subtracting the spin from their corresponding angular momentum components. We find that the quark orbital angular momentum constitutes 0.47(13) of the proton spin with almost all of it coming from the disconnected insertions.

  8. A direct biocombinatorial strategy toward next generation, mussel-glue inspired saltwater adhesives.

    PubMed

    Wilke, Patrick; Helfricht, Nicolas; Mark, Andreas; Papastavrou, Georg; Faivre, Damien; Börner, Hans G

    2014-09-10

    Biological materials exhibit remarkable, purpose-adapted properties that provide a source of inspiration for designing new materials to meet the requirements of future applications. For instance, marine mussels are able to attach to a broad spectrum of hard surfaces under hostile conditions. Controlling wet-adhesion of synthetic macromolecules by analogue processes promises to strongly impact materials sciences by offering advanced coatings, adhesives, and glues. The de novo design of macromolecules to mimic complex aspects of mussel adhesion still constitutes a challenge. Phage display allows material scientists to design specifically interacting molecules with tailored affinity to material surfaces. Here, we report on the integration of enzymatic processing steps into phage display biopanning to expand the biocombinatorial procedure and enable the direct selection of enzymatically activable peptide adhesion domains. Adsorption isotherms and single molecule force spectroscopy show that those de novo peptides mimic complex aspects of bioadhesion, such as enzymatic activation (by tyrosinase), the switchability from weak to strong binders, and adsorption under hostile saltwater conditions. Furthermore, peptide-poly(ethylene oxide) conjugates are synthesized to generate protective coatings, which possess anti-fouling properties and suppress irreversible interactions with blood-plasma protein cocktails. The extended phage display procedure provides a generic way to non-natural peptide adhesion domains, which not only mimic nature but also improve biological sequence sections extractable from mussel-glue proteins. The de novo peptides manage to combine several tasks in a minimal 12-mer sequence and thus pave the way to overcome major challenges of technical wet glues.

  9. Bone Glue Modified Asphalt: A Step towards Energy Conservation and Environment Friendly Modified Asphalts.

    PubMed

    Rizvi, Hashim Raza; Khattak, Mohammad Jamal; Gallo, August A

    2014-01-01

    Asphalt has been modified for the past several decades using various additives, including synthetic polymers. Polymer modification improves structural and engineering characteristics of the binder, which is a result of improvement in rheological characteristics of binder as well as its adhesion capability with the aggregate. Such enhancement inevitably enhances the performance characteristics of hot mix asphalts (HMA) such as fatigue life, resistance to rutting, and thermal cracking. Even though polymer-modified HMA is popular in North America and European countries, its use is still limited in developing countries of Southeast Asia due to high costs associated with its manufacturing, processing, and energy consumption. In this study, a new kind of asphalt modifier derived from animal wastes, such as bones, hides, and flesh commonly known as Bone Glue, is studied. This biomaterial which is a by-product of food and cattle industries is cheap, conveniently available, and produced locally in developing countries. The results of the research study showed that the bone glue can easily be mixed with asphalt without significantly altering the asphalt binder's viscosity and mixing and compaction temperatures of HMA. Additionally, improvements in complex shear modulus for a range of temperatures were also determined and it was found that complex shear modulus was improved by bone glue modification.

  10. Using CV-GLUE procedure in analysis of wetland model predictive uncertainty.

    PubMed

    Huang, Chun-Wei; Lin, Yu-Pin; Chiang, Li-Chi; Wang, Yung-Chieh

    2014-07-01

    This study develops a procedure that is related to Generalized Likelihood Uncertainty Estimation (GLUE), called the CV-GLUE procedure, for assessing the predictive uncertainty that is associated with different model structures with varying degrees of complexity. The proposed procedure comprises model calibration, validation, and predictive uncertainty estimation in terms of a characteristic coefficient of variation (characteristic CV). The procedure first performed two-stage Monte-Carlo simulations to ensure predictive accuracy by obtaining behavior parameter sets, and then the estimation of CV-values of the model outcomes, which represent the predictive uncertainties for a model structure of interest with its associated behavior parameter sets. Three commonly used wetland models (the first-order K-C model, the plug flow with dispersion model, and the Wetland Water Quality Model; WWQM) were compared based on data that were collected from a free water surface constructed wetland with paddy cultivation in Taipei, Taiwan. The results show that the first-order K-C model, which is simpler than the other two models, has greater predictive uncertainty. This finding shows that predictive uncertainty does not necessarily increase with the complexity of the model structure because in this case, the more simplistic representation (first-order K-C model) of reality results in a higher uncertainty in the prediction made by the model. The CV-GLUE procedure is suggested to be a useful tool not only for designing constructed wetlands but also for other aspects of environmental management.

  11. Composition and Function of Spider Glues Maintained During the Evolution of Cobwebs.

    PubMed

    Jain, Dharamdeep; Zhang, Ci; Cool, Lydia Rose; Blackledge, Todd A; Wesdemiotis, Chrys; Miyoshi, Toshikazu; Dhinojwala, Ali

    2015-10-12

    Capture silks are an interesting class of biological glues that help spiders subdue their prey. Viscid capture silk produced by the orb web spiders is a combination of hygroscopic salts that aid in water uptake and interact with adhesive glycoproteins to make them soft and sticky. The orb was a stepping stone to the evolution of new web types, but little is known about the adhesives in these webs. For instance, cobweb spiders evolved from orb-weaving ancestors and utilize glue in specialized sticky gumfoot threads rather than an elastic spiral. Early investigation suggests that gumfoot adhesives are quite different viscid glues because they lack a visible glycoprotein core, act as viscoelastic fluids rather than solids, and are largely invariant to humidity. Here, we use spectroscopic and staining methods to show that the gumfoot silk produced by Latrodectus hesperus (western black widow) is composed of hygroscopic organic salts and water insoluble glycoproteins, similar to viscid silk, in addition to a low concentration of spider coating peptides reported before. Our adhesion studies reveal that the organic salts play an important role in adhesion, similar to that seen in orb web spiders, but modulating function at much lower humidity. Our work shows more similarities in the viscid silk produced by orb web and cobweb spiders than previously anticipated and provide guidelines for developing synthetic adhesives that can work in dry to humid environments.

  12. The impact of UVB radiation on the glycoprotein glue of orb-weaving spider capture thread.

    PubMed

    Stellwagen, Sarah D; Opell, Brent D; Clouse, Mary E

    2015-09-01

    Many spider orb-webs are exposed to sunlight and the potentially damaging effects of ultraviolet B (UVB) radiation. We examined the effect of UVB on the viscoelastic glycoprotein core of glue droplets deposited on the prey capture threads of these webs, hypothesizing that webs built by species that occupy sunny habitats are less susceptible to UVB damage than are webs built by species that prefer shaded forest habitats or by nocturnal species. Threads were tested shortly after being collected in the early morning and after being exposed to UVB energy equivalent to a day of summer sun and three times this amount. Droplets kept in a dark chamber allowed us to evaluate post-production changes. Droplet volume was unaffected by treatments, indicating that UVB did not damage the hygroscopic compounds in the aqueous layer that covers droplets. UVB exposure did not affect energies of droplet extension for species from exposed and partially to mostly shaded habitats (Argiope aurantia, Leucauge venusta and Verrucosa arenata). However, UVB exposure reduced the energy of droplet extension in Micrathena gracilis from shaded forests and Neoscona crucifera, which forages at night. Only in L. venusta did the energy of droplet extension increase after the dark treatment, suggesting endogenous molecular alignment. This study adds UVB irradiation to the list of factors (humidity, temperature and strain rate) known to affect the performance of spider glycoprotein glue, factors that must be more fully understood if adhesives that mimic spider glycoprotein glue are to be produced.

  13. Using CV-GLUE procedure in analysis of wetland model predictive uncertainty.

    PubMed

    Huang, Chun-Wei; Lin, Yu-Pin; Chiang, Li-Chi; Wang, Yung-Chieh

    2014-07-01

    This study develops a procedure that is related to Generalized Likelihood Uncertainty Estimation (GLUE), called the CV-GLUE procedure, for assessing the predictive uncertainty that is associated with different model structures with varying degrees of complexity. The proposed procedure comprises model calibration, validation, and predictive uncertainty estimation in terms of a characteristic coefficient of variation (characteristic CV). The procedure first performed two-stage Monte-Carlo simulations to ensure predictive accuracy by obtaining behavior parameter sets, and then the estimation of CV-values of the model outcomes, which represent the predictive uncertainties for a model structure of interest with its associated behavior parameter sets. Three commonly used wetland models (the first-order K-C model, the plug flow with dispersion model, and the Wetland Water Quality Model; WWQM) were compared based on data that were collected from a free water surface constructed wetland with paddy cultivation in Taipei, Taiwan. The results show that the first-order K-C model, which is simpler than the other two models, has greater predictive uncertainty. This finding shows that predictive uncertainty does not necessarily increase with the complexity of the model structure because in this case, the more simplistic representation (first-order K-C model) of reality results in a higher uncertainty in the prediction made by the model. The CV-GLUE procedure is suggested to be a useful tool not only for designing constructed wetlands but also for other aspects of environmental management. PMID:24726969

  14. Bone Glue Modified Asphalt: A Step towards Energy Conservation and Environment Friendly Modified Asphalts

    PubMed Central

    Rizvi, Hashim Raza; Gallo, August A.

    2014-01-01

    Asphalt has been modified for the past several decades using various additives, including synthetic polymers. Polymer modification improves structural and engineering characteristics of the binder, which is a result of improvement in rheological characteristics of binder as well as its adhesion capability with the aggregate. Such enhancement inevitably enhances the performance characteristics of hot mix asphalts (HMA) such as fatigue life, resistance to rutting, and thermal cracking. Even though polymer-modified HMA is popular in North America and European countries, its use is still limited in developing countries of Southeast Asia due to high costs associated with its manufacturing, processing, and energy consumption. In this study, a new kind of asphalt modifier derived from animal wastes, such as bones, hides, and flesh commonly known as Bone Glue, is studied. This biomaterial which is a by-product of food and cattle industries is cheap, conveniently available, and produced locally in developing countries. The results of the research study showed that the bone glue can easily be mixed with asphalt without significantly altering the asphalt binder's viscosity and mixing and compaction temperatures of HMA. Additionally, improvements in complex shear modulus for a range of temperatures were also determined and it was found that complex shear modulus was improved by bone glue modification. PMID:27437456

  15. Physical evidence for a glue holding mineralized collagen fibrils together in bone*

    NASA Astrophysics Data System (ADS)

    Hansma, P.

    2005-03-01

    Evidence from Atomic Force Microscope indentation, pulling and imaging, and macroscopic testing and enzymatic digestion, suggests that collagen fibrils and mineral plates are not the only components of bone with mechanical roles. A ``glue'' appears to bind mineralized collagen fibrils together. Order of magnitude calculations show that less than 1% by weight of this ``glue'' profoundly affects bone fracture resistance, as it involves a remarkable natural toughening and strengthening system: sacrificial bonds and hidden length. This system dissipates large amounts of work against entropic forces while stretching out the hidden length that is exposed when sacrificial bonds break. This appears to occur when mineralized collagen fibrils are torn apart or slid against each other during bone fracture. In bone, this system depends on multivalent positive ions such as calcium ions, which allows us to follow its influence up to macroscopic fracture testing levels. Many bone matrix proteoglycans and glycoproteins have negatively charged groups at physiological pHs that could be bound together into sacrificial bonds by multivalent positive ions, and are thus natural candidates for this ``glue.'' We cannot rule out a possible involvement of nonfibrillar collagen. Precisely which candidates are involved is yet to be determined. *NSF MRL DMR00-80034, NIH GM65354, NASA BiMAT URETI NCC-1-02037 (00000532), Veeco, USARL ARO DAAD19-03-D-0004

  16. Composition and Function of Spider Glues Maintained During the Evolution of Cobwebs.

    PubMed

    Jain, Dharamdeep; Zhang, Ci; Cool, Lydia Rose; Blackledge, Todd A; Wesdemiotis, Chrys; Miyoshi, Toshikazu; Dhinojwala, Ali

    2015-10-12

    Capture silks are an interesting class of biological glues that help spiders subdue their prey. Viscid capture silk produced by the orb web spiders is a combination of hygroscopic salts that aid in water uptake and interact with adhesive glycoproteins to make them soft and sticky. The orb was a stepping stone to the evolution of new web types, but little is known about the adhesives in these webs. For instance, cobweb spiders evolved from orb-weaving ancestors and utilize glue in specialized sticky gumfoot threads rather than an elastic spiral. Early investigation suggests that gumfoot adhesives are quite different viscid glues because they lack a visible glycoprotein core, act as viscoelastic fluids rather than solids, and are largely invariant to humidity. Here, we use spectroscopic and staining methods to show that the gumfoot silk produced by Latrodectus hesperus (western black widow) is composed of hygroscopic organic salts and water insoluble glycoproteins, similar to viscid silk, in addition to a low concentration of spider coating peptides reported before. Our adhesion studies reveal that the organic salts play an important role in adhesion, similar to that seen in orb web spiders, but modulating function at much lower humidity. Our work shows more similarities in the viscid silk produced by orb web and cobweb spiders than previously anticipated and provide guidelines for developing synthetic adhesives that can work in dry to humid environments. PMID:26322742

  17. Percutaneous Glue Embolization of a Visceral Artery Pseudoaneurysm in a Case of Sickle Cell Anemia

    SciTech Connect

    Gulati, Gurpreet S.; Gulati, Manpreet S. Makharia, Govind; Hatimota, Pradeep; Saikia, Nripen; Paul, Shashi B.; Acharya, Subrat

    2006-08-15

    Although aneurysmal complications of sickle cell anemia have been described in the intracranial circulation, visceral artery pseudoaneurysms in this disease entity have not previously been reported in the literature. Conventional treatment of visceral pseudoaneurysms has been surgical ligation or resection of the aneurysm. Transcatheter embolization has emerged as an attractive, minimally invasive alternative to surgery in the treatment of these lesions. In certain situations, however, due to the unfavorable angiographic anatomy precluding safe transcatheter embolization, direct percutaneous glue injection of the pseudoaneurysm sac may be considered to achieve successful occlusion of the sac. The procedure may be rendered safer by simultaneous balloon protection of the parent artery. We describe this novel treatment modality in a case of inferior pancreaticoduodenal artery pseudoaneurysm in a patient with sickle cell anemia. Although a complication in the form of glue reflux into the parent vessel occurred that necessitated surgery, this treatment modality may be used in very selected cases (where conventional endovascular embolization techniques are not applicable) after careful selection of the balloon diameter and appropriate concentration of the glue-lipiodol mixture.

  18. Hydroxyapatite-reinforced collagen tissue engineering scaffolds

    NASA Astrophysics Data System (ADS)

    Kane, Robert J.

    Scaffolds have been fabricated from a wide variety of materials and most have showed some success, either as bone graft substitutes or as tissue engineering scaffolds. However, all current scaffold compositions and architectures suffer from one or more flaws including poor mechanical properties, lack of biological response, nondegradability, or a scaffold architecture not conducive to osteointegration. Biomimetic approaches to scaffold design using the two main components of bone tissue, collagen and hydroxyapatite, resulted in scaffolds with superior biological properties but relatively poor mechanical properties and scaffold architecture. It was hypothesized that by optimizing scaffold composition and architecture, HA-collagen bone tissue engineering scaffolds could provide both an excellent biological response along with improved structural properties. The mechanical properties of freeze-dried HA-collagen scaffolds, the most common type of porous HA-collagen material, were first shown to be increased by the addition of HA reinforcements, but scaffold stiffness still fell far short of the desired range. Based on limitations inherent in the freeze-dried process, a new type of leached-porogen scaffold fabrication process was developed. Proof-of-concept scaffolds demonstrated the feasibility of producing leached-porogen HA-collagen materials, and the scaffold architecture was optimized though careful selection of porogen particle size and shape along with an improved crosslinking technique. The final scaffolds exhibited substantially increased compressive modulus compared to previous types HA-collagen scaffolds, while the porosity, pore size, and scaffold permeability were tailored to be suitable for bone tissue ingrowth. An in vitro study demonstrated the capacity of the leached-porogen scaffolds to serve as a substrate for the differentiation of osteoblasts and subsequent production of new bone tissue. The new leached-porogen scaffold HA-collagen scaffolds were

  19. Using Scaffolds in Problem-Based Hypermedia

    ERIC Educational Resources Information Center

    Su, Yuyan; Klein, James D.

    2010-01-01

    This study investigated the use of scaffolds in problem-based hypermedia. Three hundred and twelve undergraduate students enrolled in a computer literacy course worked in project teams to use a hypermedia PBL program focused on designing a personal computer. The PBL program included content scaffolds, metacognitive scaffolds, or no scaffolds.…

  20. Electrospun multifunctional tissue engineering scaffolds

    NASA Astrophysics Data System (ADS)

    Wang, Chong; Wang, Min

    2014-03-01

    Tissue engineering holds great promises in providing successful treatments of human body tissue loss that current methods are unable to treat or unable to achieve satisfactory clinical outcomes. In scaffold-based tissue engineering, a highperformance scaffold underpins the success of a tissue engineering strategy and a major direction in the field is to create multifunctional tissue engineering scaffolds for enhanced biological performance and for regenerating complex body tissues. Electrospinning can produce nanofibrous scaffolds that are highly desirable for tissue engineering. The enormous interest in electrospinning and electrospun fibrous structures by the science, engineering and medical communities has led to various developments of the electrospinning technology and wide investigations of electrospun products in many industries, including biomedical engineering, over the past two decades. It is now possible to create novel, multicomponent tissue engineering scaffolds with multiple functions. This article provides a concise review of recent advances in the R & D of electrospun multifunctional tissue engineering scaffolds. It also presents our philosophy and research in the designing and fabrication of electrospun multicomponent scaffolds with multiple functions.

  1. Visualization of Neutrophil Extracellular Traps and Fibrin Meshwork in Human Fibrinopurulent Inflammatory Lesions: II. Ultrastructural Study

    PubMed Central

    Onouchi, Takanori; Shiogama, Kazuya; Matsui, Takahiro; Mizutani, Yasuyoshi; Sakurai, Kouhei; Inada, Ken-ichi; Tsutsumi, Yutaka

    2016-01-01

    Neutrophil extracellular traps (NETs) represent an extracellular, spider’s web-like structure resulting from cell death of neutrophils. NETs play an important role in innate immunity against microbial infection, but their roles in human pathological processes remain largely unknown. NETs and fibrin meshwork both showing fibrillar structures are observed at the site of fibrinopurulent inflammation, as described in our sister paper [Acta Histochem. Cytochem. 49; 109–116, 2016]. In the present study, immunoelectron microscopic study was performed for visualizing NETs and fibrin fibrils (thick fibrils in our tongue) in formalin-fixed, paraffin-embedded sections of autopsied lung tissue of legionnaire’s pneumonia. Lactoferrin and fibrinogen gamma chain were utilized as markers of NETs and fibrin, respectively. Analysis of immuno-scanning electron microscopy indicated that NETs constructed thin fibrils and granular materials were attached onto the NETs fibrils. The smooth-surfaced fibrin fibrils were much thicker than the NETs fibrils. Pre-embedding immunoelectron microscopy demonstrated that lactoferrin immunoreactivities were visible as dots on the fibrils, whereas fibrinogen gamma chain immunoreactivities were homogeneously observed throughout the fibrils. Usefulness of immunoelectron microscopic analysis of NETs and fibrin fibrils should be emphasized.

  2. In vitro formation and i vivo clearance of fibrinogen: fibrin complexes.

    PubMed

    Sherman, L A; Harwig, S; Lee, J

    1975-07-01

    Fbrinogen:fibrin complexes have been previously described in various thrombotic disorders. To evaluate further the properties of fibrinogen:fibrin complexes, and theirin vitro and in vivo behavior, soluable fibrinogen:fibrin complexes have been formed invitro using mixtures of '131l-fibrinogen ('131l-F) and '125l-fibrin ('125l-fb). By means of Sepharose 4B chromatography, a macromolecular complex (peak one) containing both moieties could be separated from a lower molecular weight peak two containg noncomplexed material. The latter eluted at the same position as did intact fibrogen. Both the '131l-F and '125l-fb components of peak one were rapidly catabolized when injected into rabbits with residual blood activity at 24 hours of 8 per cent and 4 per cent, respectively. Peak two behavedas a simple mixture with corresponding 24-hour levels at 31 per cent and 3 per cent. Gel filtration of postinjuection plasma samples demonstrated that peak one remained as macromolecular complex. Preinjection crosslinking of the F:fb complex with factor xiii did not substantially change the blood clearance. Prior blockage of the reticuloendotheial system with Thorotrast or carbon resulted in impaired clearance of peak one. The data provide evidence that fibrinogen and fibrin can form a macromolecular complex which is stable both in vitro and vivo. Further, the reticuloendotheialsystem was shown to mediate the the in vivo clearance of this complex. This latterfinding may be of pathophysiologic significance.

  3. Visualization of Neutrophil Extracellular Traps and Fibrin Meshwork in Human Fibrinopurulent Inflammatory Lesions: II. Ultrastructural Study.

    PubMed

    Onouchi, Takanori; Shiogama, Kazuya; Matsui, Takahiro; Mizutani, Yasuyoshi; Sakurai, Kouhei; Inada, Ken-Ichi; Tsutsumi, Yutaka

    2016-08-30

    Neutrophil extracellular traps (NETs) represent an extracellular, spider's web-like structure resulting from cell death of neutrophils. NETs play an important role in innate immunity against microbial infection, but their roles in human pathological processes remain largely unknown. NETs and fibrin meshwork both showing fibrillar structures are observed at the site of fibrinopurulent inflammation, as described in our sister paper [Acta Histochem. Cytochem. 49; 109-116, 2016]. In the present study, immunoelectron microscopic study was performed for visualizing NETs and fibrin fibrils (thick fibrils in our tongue) in formalin-fixed, paraffin-embedded sections of autopsied lung tissue of legionnaire's pneumonia. Lactoferrin and fibrinogen gamma chain were utilized as markers of NETs and fibrin, respectively. Analysis of immuno-scanning electron microscopy indicated that NETs constructed thin fibrils and granular materials were attached onto the NETs fibrils. The smooth-surfaced fibrin fibrils were much thicker than the NETs fibrils. Pre-embedding immunoelectron microscopy demonstrated that lactoferrin immunoreactivities were visible as dots on the fibrils, whereas fibrinogen gamma chain immunoreactivities were homogeneously observed throughout the fibrils. Usefulness of immunoelectron microscopic analysis of NETs and fibrin fibrils should be emphasized. PMID:27682015

  4. Using blocking peptides to control and analyze the mechanical properties of single fibrin fibers

    NASA Astrophysics Data System (ADS)

    Maddi, Pranav; O'Brien, E. Tim, III; Gorkun, Oleg; Falvo, Michael R.

    2011-10-01

    Fibrin is the main structural protein involved in blood clotting, and exhibits high strength and elasticity. Fibrin study traditionally focuses on fully formed clots, whereas we employ new AFM nanoManipulation techniques to study single fibrin fiber mechanics. We used 4 and 10 residue peptides to interfere with the knob-hole and αC interactions involved in fibrin polymerization to evaluate the contribution of each interaction to the fiber's mechanical properties. We varied the concentration of each peptide present during polymerization to find the concentration that inhibited polymerization by half. The presence of either peptide during fibrin polymerization did not affect single fiber breaking strain (δLL0). The breaking force of all treated fibers reduced from 10-50nN to 2-10nN, suggesting treated fibers are thinner or are the same diameter with some inhibition of interactions. Fibers polymerized with the knob-hole targeting peptide visibly lost elasticity after 100% strain, while fibers polymerized with the αC targeting peptide lost elasticity after reaching 150% strain, suggesting that the knob-hole interactions control single fiber elasticity.

  5. Flow and delta-P dictate where thrombin, fibrin, and von Willebrand Factor will be found.

    PubMed

    Diamond, Scott L

    2016-05-01

    Hemostasis occurs in two different topological scenarios: complete severing of a vessel or disruption of the vessel wall. Either to meet the daily rigors of active life or during an acute trauma, hemostasis involves the regulated and self-limiting production of thrombin to stop bleeding. In contrast, arterial and venous thrombosis typically involves the unregulated, intraluminal growth of a clot, in the absence of bleeding. For either hemostasis or thrombosis, the presence of flow and pressure gradients (delta-P, ΔP) dictates when and where thrombin and fibrin are located and in what quantity. For hemostatic clots, fibrin formation helped limit clot growth. We found that γ'-fibrinogen had a role in limiting clot growth via anti-thrombin activity at venous, but not arterial conditions. For hemophilic blood, severe factor deficiency (<1% healthy) led to a defect in both platelet and fibrin deposition under flow. However, moderate deficiency, which is associated with a less severe bleeding phenotype, had normalized platelet function but still lacked fibrin production. We conclude signaling levels of thrombin can be generated during moderate hemophilia to sufficiently activate platelets to achieve primary hemostasis, even if fibrin formation remains defective. Finally, as a clot grows, shear stresses can become sufficiently extreme in diseased arteries to drive von Willebrand Factor self-association into massive fibers, potentially the final burst of clot growth towards full thrombotic occlusion. PMID:27207416

  6. Flow and delta-P dictate where thrombin, fibrin, and von Willebrand Factor will be found.

    PubMed

    Diamond, Scott L

    2016-05-01

    Hemostasis occurs in two different topological scenarios: complete severing of a vessel or disruption of the vessel wall. Either to meet the daily rigors of active life or during an acute trauma, hemostasis involves the regulated and self-limiting production of thrombin to stop bleeding. In contrast, arterial and venous thrombosis typically involves the unregulated, intraluminal growth of a clot, in the absence of bleeding. For either hemostasis or thrombosis, the presence of flow and pressure gradients (delta-P, ΔP) dictates when and where thrombin and fibrin are located and in what quantity. For hemostatic clots, fibrin formation helped limit clot growth. We found that γ'-fibrinogen had a role in limiting clot growth via anti-thrombin activity at venous, but not arterial conditions. For hemophilic blood, severe factor deficiency (<1% healthy) led to a defect in both platelet and fibrin deposition under flow. However, moderate deficiency, which is associated with a less severe bleeding phenotype, had normalized platelet function but still lacked fibrin production. We conclude signaling levels of thrombin can be generated during moderate hemophilia to sufficiently activate platelets to achieve primary hemostasis, even if fibrin formation remains defective. Finally, as a clot grows, shear stresses can become sufficiently extreme in diseased arteries to drive von Willebrand Factor self-association into massive fibers, potentially the final burst of clot growth towards full thrombotic occlusion.

  7. Dynamic behaviors of astrocytes in chemically modified fibrin and collagen hydrogels.

    PubMed

    Seyedhassantehrani, Negar; Li, Yongchao; Yao, Li

    2016-05-16

    Astrocytes play a critical role in supporting the normal physiological function of neurons in the central nervous system (CNS). Astrocyte transplantation can potentially promote axonal regeneration and functional recovery after spinal cord injury (SCI). Fibrin and collagen hydrogels provide growth-permissive substrates and serve as carriers for therapeutic cell transplantation into an injured spinal cord. However, the application of fibrin and collagen hydrogels may be limited due to their relatively rapid degradation rate in vivo. In this study, immature astrocytes isolated from neonatal rats were grown in fibrin hydrogels containing aprotinin and collagen hydrogels crosslinked with poly(ethylene glycol) ether tetrasuccinimidyl glutarate (4S-StarPEG), and the cell behavior in these hydrogels was studied. The cell viability of astrocytes in the hydrogels was tested using the LIVE/DEAD® assay and the AlamarBlue® assay, and this study showed that astrocytes maintained good viability in these hydrogels. The cell migration study showed that astrocytes migrated in the fibrin and collagen hydrogels, and the migration speed is similar in these hydrogels. The crosslinking of collagen hydrogels with 4S-StarPEG did not change the astrocyte migration speed. However, the addition of aprotinin in the fibrin hydrogel inhibited astrocyte migration. The expression of chondroitin sulfate proteoglycan (CSPG), including NG2, neurocan, and versican, by astrocytes grown in the hydrogels was analyzed by quantitative RT-PCR. The expression of NG2, neurocan, and versican by the cells in these hydrogels was not significantly different. PMID:27079938

  8. Treatment of gingival recession using free gingival graft with fibrin fibronectin sealing system: A novel approach

    PubMed Central

    Srinivas, B. V. V.; Rupa, N.; Halini Kumari, K. V.; Rajender, A.; Reddy, M. Narendra

    2015-01-01

    Periodontal plastic surgery is the branch of periodontology that is focused mainly on the correction or elimination of mucogingival problems associated with lack of attached gingiva, a shallow vestibule and aberrant frenum. Various mucogingival surgical procedures are used to halt the progression of the gingival recession and to correct poor esthetic appearance. Free gingival autograft is one of the most common techniques used for a gingival recession in areas of inadequate attached gingiva in the mandibular anterior region. Fibrin sealants are human plasma derivatives that mimic the final stages of blood coagulation, forming a fibrin clot. Fibrin Sealants enhances the overall outcome of surgical intervention because of their hemostatic, adhesive, and healing properties. These properties of fibrin sealants may reduce operating time, prevent complications, and enhance the overall outcome of many surgical interventions. Hence, this case report aims to investigate the clinical effectiveness of free gingival graft along with the commercially available fibrin-fibronectin sealing system (Tissucol®) in the treatment of Miller's class II gingival recession. PMID:26538956

  9. Visualization of Neutrophil Extracellular Traps and Fibrin Meshwork in Human Fibrinopurulent Inflammatory Lesions: II. Ultrastructural Study

    PubMed Central

    Onouchi, Takanori; Shiogama, Kazuya; Matsui, Takahiro; Mizutani, Yasuyoshi; Sakurai, Kouhei; Inada, Ken-ichi; Tsutsumi, Yutaka

    2016-01-01

    Neutrophil extracellular traps (NETs) represent an extracellular, spider’s web-like structure resulting from cell death of neutrophils. NETs play an important role in innate immunity against microbial infection, but their roles in human pathological processes remain largely unknown. NETs and fibrin meshwork both showing fibrillar structures are observed at the site of fibrinopurulent inflammation, as described in our sister paper [Acta Histochem. Cytochem. 49; 109–116, 2016]. In the present study, immunoelectron microscopic study was performed for visualizing NETs and fibrin fibrils (thick fibrils in our tongue) in formalin-fixed, paraffin-embedded sections of autopsied lung tissue of legionnaire’s pneumonia. Lactoferrin and fibrinogen gamma chain were utilized as markers of NETs and fibrin, respectively. Analysis of immuno-scanning electron microscopy indicated that NETs constructed thin fibrils and granular materials were attached onto the NETs fibrils. The smooth-surfaced fibrin fibrils were much thicker than the NETs fibrils. Pre-embedding immunoelectron microscopy demonstrated that lactoferrin immunoreactivities were visible as dots on the fibrils, whereas fibrinogen gamma chain immunoreactivities were homogeneously observed throughout the fibrils. Usefulness of immunoelectron microscopic analysis of NETs and fibrin fibrils should be emphasized. PMID:27682015

  10. A Synthetic Fibrin-Crosslinking Polymer for Modulating Clot Properties and Inducing Hemostasis

    PubMed Central

    Chan, Leslie W.-G.; Wang, Xu; Wei, Hua; Pozzo, Lilo D.; White, Nathan J.; Pun, Suzie H.

    2015-01-01

    Clotting factor replacement is the standard management of acute bleeding in congenital and acquired bleeding disorders. We present a synthetic approach to hemostasis using an engineered hemostatic polymer (PolySTAT) that circulates innocuously in the blood, identifies sites of vascular injury, and promotes clot formation to stop bleeding. PolySTAT induces hemostasis by crosslinking the fibrin matrix within clots, mimicking the function of the transglutaminase Factor XIII. Furthermore, synthetic PolySTAT binds specifically to fibrin monomers and is uniformly integrated into fibrin fibers during fibrin polymerization, resulting in a fortified, hybrid polymer network with enhanced resistance to enzymatic degradation. In vivo hemostatic activity was confirmed in a rat model of trauma and fluid resuscitation in which intravenous administration of PolySTAT improved survival by reducing blood loss and resuscitation fluid requirements. PolySTAT-induced fibrin crosslinking is a novel approach to hemostasis utilizing synthetic polymers for non-invasive modulation of clot architecture with potentially wide-ranging therapeutic applications. PMID:25739763

  11. A comparative study of skin cell activities in collagen and fibrin constructs.

    PubMed

    Law, Jia Xian; Musa, Faiza; Ruszymah, Bt Hj Idrus; El Haj, Alicia J; Yang, Ying

    2016-09-01

    Collagen and fibrin are widely used in tissue engineering due to their excellent biocompatibility and bioactivities that support in vivo tissue formation. These two hydrogels naturally present in different wound healing stages with different regulatory effects on cells, and both of them are mechanically weak in the reconstructed hydrogels. We conducted a comparative study by the growth of rat dermal fibroblasts or dermal fibroblasts and epidermal keratinocytes together in collagen and fibrin constructs respectively with and without the reinforcement of electrospun poly(lactic acid) nanofiber mesh. Cell proliferation, gel contraction and elastic modulus of the constructs were measured on the same gels at multiple time points during the 22 day culturing period using multiple non-destructive techniques. The results demonstrated considerably different cellular activities within the two types of constructs. Co-culturing keratinocytes with fibroblasts in the collagen constructs reduced the fibroblast proliferation, collagen contraction and mechanical strength at late culture point regardless of the presence of nanofibers. Co-culturing keratinocytes with fibroblasts in the fibrin constructs promoted fibroblast proliferation but exerted no influence on fibrin contraction and mechanical strength. The presence of nanofibers in the collagen and fibrin constructs played a favorable role on the fibroblast proliferation when keratinocytes were absent. Thus, this study exhibited new evidence of the strong cross-talk between keratinocytes and fibroblasts, which can be used to control fibroblast proliferation and construct contraction. This cross-talk activity is extracellular matrix-dependent in terms of the fibrous network morphology, density and strength. PMID:27349492

  12. Characterization of Fibrin and Collagen Gels for Engineering Wound Healing Models

    PubMed Central

    Moreno-Arotzena, Oihana; Meier, Johann G.; del Amo, Cristina; García-Aznar, José Manuel

    2015-01-01

    Hydrogels are used for 3D in vitro assays and tissue engineering and regeneration purposes. For a thorough interpretation of this technology, an integral biomechanical characterization of the materials is required. In this work, we characterize the mechanical and functional behavior of two specific hydrogels that play critical roles in wound healing, collagen and fibrin. A coherent and complementary characterization was performed using a generalized and standard composition of each hydrogel and a combination of techniques. Microstructural analysis was performed by scanning electron microscopy and confocal reflection imaging. Permeability was measured using a microfluidic-based experimental set-up, and mechanical responses were analyzed by rheology. We measured a pore size of 2.84 and 1.69 μm for collagen and fibrin, respectively. Correspondingly, the permeability of the gels was 1.00·10−12 and 5.73·10−13 m2. The shear modulus in the linear viscoelastic regime was 15 Pa for collagen and 300 Pa for fibrin. The gels exhibited strain-hardening behavior at ca. 10% and 50% strain for fibrin and collagen, respectively. This consistent biomechanical characterization provides a detailed and robust starting point for different 3D in vitro bioapplications, such as collagen and/or fibrin gels. These features may have major implications for 3D cellular behavior by inducing divergent microenvironmental cues. PMID:26290683

  13. [Propolis. The bee glue as presented by the Graeco-Roman literature].

    PubMed

    Golder, Werner

    2004-01-01

    The bee glue, commonly known as propolis, has been employed for medical purposes already in teh ancient world. More than 15 Greek and Roman authors report on the preparation and application of the so-called third natural product of the bees (besides honey and wax). Aristoteles described the fundamental issues of its biology in his 'Historia Animalium' correctly. The bulk of propolis is obtained from the barks of poplars. Once carried in the hives, the glue is used to stabilize the cells and honeycombs and to protect the bees against invaders and cold weather. Propolis has been chiefly employed for the preparation of ointment and plasters. For this purpose, the viscous raw material was purified, moulded and boiled. In most preparations, the bee glue was only one of many (up to 20) pharmacologically active constituents and came to five to 20% of the mixture. Only rarely, a single drug therapy was using propolis was carried out. The application of the glue was most successful in general surgery and casualties. In that respect, the ancient physicians took advantage of the anti-edematous and anti-infectious properties of the substance. Thus, it was used to treat bumps, indurations, and slow-healing wounds. Moreover, cataplasms against swollen cervical nodes and indurations of the female breast often contained propolis. Finally, bee glue proved successful for the treatment of chronic backache and pain in the hip as well as fresh injuries of muscles and tendons. In the sector of skin diseases, lichens and condylomata were found to respond well to propolis. ALl this indications have been a matter of several records. However, the successful use of propolis in diseases of the stomach and liver has ben reported solely by Alexander of Tralles (6th century AD). Not counting the internal diseases, the spectrum of indications for propolis has not substantially changed as compared to the classical antiquity. Interestingly, radiation therapists have adopted the ancient remedy and

  14. Exploring the scaffold universe of kinase inhibitors.

    PubMed

    Hu, Ye; Bajorath, Jürgen

    2015-01-01

    The scaffold concept was applied to systematically determine, analyze, and compare core structures of kinase inhibitors. From publicly available inhibitors of the human kinome, scaffolds and cyclic skeletons were systematically extracted and organized taking activity data, structural relationships, and retrosynthetic criteria into account. Scaffold coverage varied greatly across the kinome, and many scaffolds representing compounds with different activity profiles were identified. The majority of kinase inhibitor scaffolds were involved in well-defined yet distinct structural relationships, which had different consequences on compound activity. Scaffolds exclusively representing highly potent compounds were identified as well as structurally analogous scaffolds with very different degrees of promiscuity. Scaffold relationships presented herein suggest a variety of hypotheses for inhibitor design. Our detailed organization of the kinase inhibitor scaffold universe with respect to different activity and structural criteria, all scaffolds, and the original compound data assembled for our analysis are made freely available.

  15. Antifungal efficacy of amphotericin B encapsulated fibrin microsphere for treating Cryptococcus neoformans infection in Swiss albino mice.

    PubMed

    Khan, Azmat Ali; Jabeen, Mumtaz; Alanazi, Amer M; Khan, Abdul Arif

    2016-01-01

    A natural and biocompatible fibrin microsphere is one of the most promising dual delivery vehicle as compared to other traditionally designed delivery modalities. It represents sustained delivery of encapsulated drug and is easily biodegradable in the blood circulation. In the present study, we evaluated the systemic augmentation of the antifungal activity of amphotericin B loaded in fibrin microsphere (AMB-fibrin microsphere) against cryptococcosis in Swiss albino mice. Mice infected with Cryptococcus neoformans were treated with 0.5mg/kg AMB-fibrin microsphere that was given alternately for 7 days. The antifungal potential of AMB-fibrin microsphere was assessed on the basis of reduction of cfu count in the systemic circulation and various vital organs of infected mice. The formulation was found to be highly effective in reducing intracellular pathogen from the experimental animals where fibrin microsphere significantly controlled the release of amphotericin B for longer time duration. The AMB-fibrin microsphere chemotherapy was significantly more effective than free amphotericin B in reducing the fungal burden and showed better survival efficacy (p<0.05). The current study demonstrating the use of novel amphotericin B loaded fibrin microsphere not only imparts protection to the encapsulated amphotericin B but also offers an effective strategy to decrease the drug associated toxicities. PMID:27294976

  16. Modulation of 3D Fibrin Matrix Stiffness by Intrinsic Fibrinogen–Thrombin Compositions and by Extrinsic Cellular Activity

    PubMed Central

    Duong, Haison; Wu, Benjamin

    2009-01-01

    Fibrin is a substance formed through catalytic conversion of coagulation constituents: fibrinogen and thrombin. The kinetics of the two constituents determines the structural properties of the fibrin architecture. We have shown previously that changing the fibrinogen and thrombin concentrations in the final three-dimensional (3D) fibrin matrix influenced cell proliferation and differentiation. In this study, we further examined the effect of changing fibrinogen and thrombin concentrations in the absence or presence of fibroblasts on the structural modulus or stiffness of 3D fibrin matrices. We have prepared fibroblast-free and fibroblast-embedded 3D fibrin matrices of different fibrinogen and thrombin formulations, and tested the stiffness of these constructs using standard mechanical testing assays. Results showed that there was a corresponding increase in stiffness with increasing thrombin and fibrinogen concentrations; the increase was more notable with fibrinogen and to a lesser degree with thrombin. The effect of fibroblasts on the stiffness of the fibrin construct was also examined. We have observed a small increase in the stiffness of the fibroblast-incorporated fibrin construct as they proliferated and exhibited spreading morphology. To our knowledge, this is the first comprehensive report detailing the relationship between fibrinogen and thrombin concentrations, cell proliferation, and stiffness in 3D fibrin matrices. The data obtained may lead to optimally design suitable bioscaffolds where we can control both cell proliferation and structural integrity for a variety of tissue engineering applications. PMID:19309239

  17. The use of fibrin beads for tissue engineering and subsequential transplantation.

    PubMed

    Perka, C; Arnold, U; Spitzer, R S; Lindenhayn, K

    2001-06-01

    New biological technologies such as tissue engineering procedures require the transplantation of functionally active cells within supportive carrier matrices. This paper describes a sequential culture procedure for different types of cells. The technique includes the initial preparation of a mixed alginate-fibrin vehicle that guaranteed an initial cell proliferation and differentiation to establish a stable matrix structure, and the subsequent removal of the alginate component prior to transplantation to circumvent the problem of missing bioresorbability. The resulting biodegradable carrier is mechanically stable and promotes further tissue maturation. Chondrocytes, periosteal-derived cells, as well as nucleus pulposus cells were entrapped in fibrin-alginate beads and in fibrin beads. The results indicate a promising technical approach to create stable transplants for reconstructive surgery of cartilage and bone.

  18. The role of staphylothrombin-mediated fibrin deposition in catheter-related Staphylococcus aureus infections.

    PubMed

    Vanassche, Thomas; Peetermans, Marijke; Van Aelst, Lucas N L; Peetermans, Willy E; Verhaegen, Jan; Missiakas, Dominique M; Schneewind, Olaf; Hoylaerts, Marc F; Verhamme, Peter

    2013-07-01

    Staphylococcus aureus (S. aureus) is a frequent cause of catheter-related infections. S. aureus secretes the coagulases staphylocoagulase and von Willebrand factor-binding protein, both of which form a staphylothrombin complex upon binding to prothrombin. Although fibrinogen and fibrin facilitate the adhesion of S. aureus to catheters, the contribution of staphylothrombin-mediated fibrin has not been examined. In this study, we use a S. aureus mutant lacking both coagulases (Δcoa/vwb) and dabigatran, a pharmacological inhibitor of both staphylothrombin and thrombin, to address this question. Genetic absence or chemical inhibition of pathogen-driven coagulation reduced both fibrin deposition and the retention of S. aureus on catheters in vitro. In a mouse model of jugular vein catheter infection, dabigatran reduced bacterial load on jugular vein catheters, as well as metastatic kidney infection. Importantly, inhibition of staphylothrombin improved the efficacy of vancomycin treatment both in vitro and in the mouse model. PMID:23532100

  19. Nanotechnology Biomimetic Cartilage Regenerative Scaffolds

    PubMed Central

    Sardinha, Jose Paulo; Myers, Simon

    2014-01-01

    Cartilage has a limited regenerative capacity. Faced with the clinical challenge of reconstruction of cartilage defects, the field of cartilage engineering has evolved. This article reviews current concepts and strategies in cartilage engineering with an emphasis on the application of nanotechnology in the production of biomimetic cartilage regenerative scaffolds. The structural architecture and composition of the cartilage extracellular matrix and the evolution of tissue engineering concepts and scaffold technology over the last two decades are outlined. Current advances in biomimetic techniques to produce nanoscaled fibrous scaffolds, together with innovative methods to improve scaffold biofunctionality with bioactive cues are highlighted. To date, the majority of research into cartilage regeneration has been focused on articular cartilage due to the high prevalence of large joint osteoarthritis in an increasingly aging population. Nevertheless, the principles and advances are applicable to cartilage engineering for plastic and reconstructive surgery. PMID:24883273

  20. Multilayered Magnetic Gelatin Membrane Scaffolds

    PubMed Central

    Samal, Sangram K.; Goranov, Vitaly; Dash, Mamoni; Russo, Alessandro; Shelyakova, Tatiana; Graziosi, Patrizio; Lungaro, Lisa; Riminucci, Alberto; Uhlarz, Marc; Bañobre-López, Manuel; Rivas, Jose; Herrmannsdörfer, Thomas; Rajadas, Jayakumar; De Smedt, Stefaan; Braeckmans, Kevin; Kaplan, David L.; Dediu, V. Alek

    2016-01-01

    A versatile approach for the design and fabrication of multilayer magnetic scaffolds with tunable magnetic gradients is described. Multilayer magnetic gelatin membrane scaffolds with intrinsic magnetic gradients were designed to encapsulate magnetized bioagents under an externally applied magnetic field for use in magnetic-field-assisted tissue engineering. The temperature of the individual membranes increased up to 43.7 °C under an applied oscillating magnetic field for 70 s by magnetic hyperthermia, enabling the possibility of inducing a thermal gradient inside the final 3D multilayer magnetic scaffolds. On the basis of finite element method simulations, magnetic gelatin membranes with different concentrations of magnetic nanoparticles were assembled into 3D multilayered scaffolds. A magnetic-gradient-controlled distribution of magnetically labeled stem cells was demonstrated in vitro. This magnetic biomaterial–magnetic cell strategy can be expanded to a number of different magnetic biomaterials for various tissue engineering applications. PMID:26451743

  1. Determination of infectivity of transforming avian sarcoma virus and parotitis virus in fibrin-embedded monolayer cultures.

    PubMed

    Jandejsek, J; Spohr, P

    1982-09-01

    A sensitive and reproducible technique for titration of transforming avian sarcoma virus, Rous sarcoma virus (RSV), in chick embryo cell monolayers embedded between two layers of a solid fibrin coagulum was developed. The foci of RSV-transformed fibrinolysis-exhibiting cells locally attacked the surrounding fibrin and were identifiable as plaque-like cell-free areas of retraction easily scored against the background of cells stained with neutral red. In comparison to the conventional assay in agar, the assay in fibrin proved more sensitive and less time-consuming. The titration technique in fibrin was also used for plaquing a cytopathogenic virus, parotitis virus, but the titration by conventional plaque assay in agar and the technique in fibrin yielded similar results in this case.

  2. Fibrin network architectures in pure platelet-rich plasma as characterized by fiber radius and correlated with clotting time.

    PubMed

    Perez, Amanda G M; Rodrigues, Ana A; Luzo, Angela C M; Lana, José F S D; Belangero, William D; Santana, Maria H A

    2014-08-01

    Fibrin networks are obtained through activation of platelet-rich plasma (PRP) for use in tissue regeneration. The importance of fibrin networks relies on mediation of release of growth factors, proliferation of tissue cells and rheological properties of the fibrin gels. Activation of PRP usually involves the decomposition of fibrinogen by agonists, in a wide range of concentrations. Therefore fibrin networks with a large structural diversity are formed, making comparative evaluations difficult. In order to standardize the fibrin networks, we used the statistical techniques central composite rotatable design and response-surface analysis, to correlate the radius of the fibers with the ratios between the agonists (autologous serum/calcium chloride) and agonist/PRP. From an individual and interactive analysis of the variables, architectures characterized by thick, medium and thin fibers were delineated on the response-surface. Furthermore, the architectures were correlated with coagulation time. This approach is valuable for standardizing the PRP preparation for clinical applications.

  3. C-reactive protein and fibrin clot strength measured by thrombelastography after coronary stenting.

    PubMed

    Kreutz, Rolf P; Owens, Janelle; Breall, Jeffrey A; Lu, Deshun; von der Lohe, Elisabeth; Bolad, Islam; Sinha, Anjan; Flockhart, David A

    2013-04-01

    Inflammation is implicated in the progression of coronary artery disease and the molecular processes of inflammation and thrombosis are closely intertwined. Elevated levels of C-reactive protein (CRP) have been associated with an elevated risk of adverse ischaemic events after coronary stenting and hypercoagulability. Heightened whole blood clot strength measured by thrombelastography (TEG) has been associated with adverse ischaemic events after stenting. We intended to examine the relationship of CRP to plasma fibrin clot strength in patients after coronary stenting. Plasma fibrin clot strength was measured by TEG in 54 patients 16-24 h after undergoing elective percutaneous coronary intervention (PCI). Coagulation was induced in citrated plasma by addition of kaolin and CaCl2. Plasma levels of CRP and fibrinogen were measured by enzyme-linked immunoassay. Increasing quartiles of CRP were associated with increasing levels of maximal plasma fibrin clot strength measured by TEG (P < 0.001) and increasing BMI (P = 0.04). Patients in the highest quartile of CRP had significantly higher maximal fibrin clot strength (G) than the patients in the lowest quartile (G: 3438 ± 623 vs. 2184 ± 576 dyn/cm, P < 0.0001). Fibrinogen concentration was not significantly different across quartiles of CRP (P = 0.97). Patients with established coronary artery disease undergoing coronary stenting who have elevated CRP after PCI exhibit heightened maximal plasma fibrin clot strength as compared with those with low CRP. Thrombotic risk associated with elevated CRP may be linked to procoagulant changes and high tensile fibrin clot strength independent of fibrinogen concentration.

  4. Mesenchymal Stromal Cells form Vascular Tubes when Placed in Fibrin Sealant and Accelerate Wound Healing in Vivo

    PubMed Central

    Mendez, Julio J.; Ghaedi, Mahboobe; Sivarapatna, Amogh; Dimitrievska, Sashka; Shao, Zhen; Osuji, Chinedum; Steinbacher, Derek M.; Leffell, David J.; Niklason, Laura E.

    2014-01-01

    Non-healing, chronic wounds are a growing public health problem and may stem from insufficient angiogenesis in affected sites. Here, we have developed a fibrin formulation that allows adipose-derived mesenchymal stromal cells (ADSCs) to form tubular structures in vitro. The tubular structures express markers of endothelium, including CD31 and VE-Cadherin, as well as the pericyte marker NG2. The ability for the MSCs to form tubular structures within the fibrin gels was directly dependent on the stoichiometric ratios of thrombin and fibrinogen and the resulting gel concentration, as well as on the presence of bFGF. Fibrin gel formulations that varied in stiffness were tested. ADSCs that are embedded in a stiff fibrin formulation express VE-cadherin and CD31 as shown by PCR, FACS and immunostaining. Confocal imaging analysis demonstrated that tubular structures formed, containing visible lumens, in the stiff fibrin gels in vitro. There was also a difference in the amounts of bFGF secreted by ADSCs grown in the stiffer gels as compared to softer gels. Additionally, hAT-MSCs gave rise to perfusable vessels that were VE-cadherin positive after subcutaneous injection into mice, whereas the softer fibrin formulation containing ADSCs did not. The application of ADSCs delivered in the stiff fibrin gels allowed for the wounds to heal more quickly, as assessed by wound size, amount of granulation tissue and collagen content. Interestingly, following 5 days of healing, the ADSCs remained within the fibrin gel and did not integrate into the granulation tissue of healing wounds in vivo. These data show that ADSCs are able to form tubular structures within fibrin gels, and may also contribute to faster wound healing, as compared with no treatment or to wounds treated with fibrin gels devoid of ADSCs. PMID:25433608

  5. Use of Platelet-Rich Fibrin over Skin Wounds: Modified Secondary Intention Healing

    PubMed Central

    Desai, Chirag B; Mahindra, Uma R; Kini, Yogesh K; Bakshi, Makarand K

    2013-01-01

    The healing process after any surgical intervention has always posed a challenge for the surgeons. In spite of the advances in wound closure techniques and devices, there is a crucial need for newer methods of enhancing the healing process to achieve optimal outcomes. Fibrin adhesives and platelet concentrates have proven useful in various treatment modalities in the fields of microvascular and plastic surgery. This case report shows its unique use in the field of maxillofacial and cutaneous surgery. It shows an innovative technique of enhancement of skin wound healing by local application of platelet-rich fibrin. PMID:23723604

  6. Thrombus on Indwelling Central Venous Catheters: The Histopathology of 'Fibrin Sheaths'

    SciTech Connect

    Suojanen, James Norman; Brophy, David Paul; Nasser, Imad

    2000-03-15

    Purpose: Central venous catheters (CVC) may fail for many reasons, though 'fibrin sheaths' blocking catheter ports are usually implicated. We examined the sheaths removed from dialysis catheters to determine their histopathology.Methods: Ten catheter strippings were performed and the removed material was studied grossly and microscopically.Results: The histologic specimens showed thrombus both with and without a proteinaceous sheath.Conclusion: Dialysis catheters fail because of thrombus formation. This can occur in either the absence or presence of a protein coating on the catheter, the so-called 'fibrin sheath.'.

  7. Plasma fibrin clot phenotype independently affects intracoronary thrombus ultrastructure in patients with acute myocardial infarction.

    PubMed

    Zalewski, Jaroslaw; Bogaert, Jan; Sadowski, Marcin; Woznicka, Olga; Doulaptsis, Konstantinos; Ntoumpanaki, Maria; Ząbczyk, Michal; Nessler, Jadwiga; Undas, Anetta

    2015-06-01

    Determinants of intracoronary thrombus (ICT) composition in patients with ST-elevation myocardial infarction (STEMI) are largely unknown. We sought to investigate whether plasma fibrin phenotype and platelet reactivity affect ICT ultrastructure. We assessed the content of fibrin, platelets and erythrocytes including polyhedrocytes by scanning electron microscopy on the surface and inside ICT aspirated from 80 STEMI patients within 12 hours since chest pain onset. Plasma fibrin clot permeability (Ks), which indicates the average pore size, lysis time (t50 %), platelet reactivity index (PRI) and ADP-induced platelet aggregation (ADP5, 20µM) were evaluated on admission. All patients received aspirin and 45 (56.3 %) 600 mg of clopidogrel, 80 (60-120) min prior to aspiration. Higher content of fibrin (61.6 vs 34.3 %, P< 0.0001) and platelets (8.2 vs 4.8 %, P=0.018) and lower erythrocyte content (15.8 vs 42.9 %, P< 0.0001) were found on ICT surface compared with its inner part. After adjustment for fibrinogen, in both ICT parts fibrin content was correlated with Ks (r≤-0.55, P< 0.0001) and t50 % (r≥ 0.29, P≤ 0.02) but not with PRI and ADP5,20µM. Polyhedrocytes were observed in 16 (20 %) patients and their large amount expressed as ≥ 50 % fields of view covered by polyhedrocytes was associated with the lower PRI values (40 vs 69 %, P=0.015), but not Ks or t50 %. By multivariate regression, Ks (β=-0.62, P< 0.0001), clopidogrel pretreatment (β=-0.36, P< 0.001), ischemia time (β=0.19, P=0.044) and family history (β=0.18, P=0.049) independently predicted fibrin content in the whole ICT (R²=0.65, P< 0.0001). Formation of denser plasma fibrin clots is independently associated with high fibrin content within the ICT in STEMI. PMID:25739375

  8. Quantitative analysis of AgNOR proteins in buccal epithelial cells of Indian street boys addicted to gasp 'golden glue'.

    PubMed

    Mondal, Nandan Kumar; Ghosh, Sreenita; Ray, Manas Ranjan

    2011-11-01

    The effect of glue snuffle on the expression of argyrophilic nucleolar organizer regions (AgNORs), an indicator of ribosome biosynthesis, in epithelial cells of oral mucosa has been investigated. AgNOR was evaluated by cytochemical staining in 148 Indian street boys (median age 12 year) who had different bad addictions like tobacco smoking, chewing and most importantly inhaling glue and 20 age- and body mass index-matched school boys who had no such type of bad habit. Compared with school boys, glue addicted street boys showed remarkably increased number of AgNOR dots per nucleus (9.38±1.84 vs. 3.12±0.87, p<0.001), AgNOR size (1.34±0.52 vs. 0.43±0.02 μm(2), p<0.001) and percentage of AgNOR occupied nuclear area (9.38±2.12 vs. 0.99±0.03%, p<0.001). Increase in number and size of the dots is also higher in tobacco smokers and chewers when compared with school boys but a remarkable difference was recorded in glue addicted boys. The changes in AgNOR expression were positively associated with years of addiction after controlling potential confounders. Thus, glue snuffle appeared to be a risk factor for abnormal cell growth via up-regulation of ribosome biogenesis. PMID:20541922

  9. Laser microstructured biodegradable scaffolds.

    PubMed

    Koroleva, Anastasia; Kufelt, Olga; Schlie-Wolter, Sabrina; Hinze, Ulf; Chichkov, Boris

    2013-10-01

    The two-photon polymerization technique (2PP) uses non-linear absorption of femtosecond laser pulses to selectively polymerize photosensitive materials. 2PP has the ability to fabricate structures with a resolution from tens of micrometers down to hundreds of nanometers. Three-dimensional microstructuring by the 2PP technique provides many interesting possibilities for biomedical applications. This microstructuring technique is suitable with many biocompatible polymeric materials, such as polyethylene glycol, polylactic acid, polycaprolactone, gelatin, zirconium-based hybrids, and others. The process of fabrication does not require clean room conditions and does not use hazard chemicals or high temperatures. The most beneficial property of 2PP is that it is capable of producing especially complex three-dimensional (3-D) structures, including devices with overhangs, without using any supportive structure. The flexibility in controlling geometries and feature sizes and the possibility to fabricate structures without the addition of new material layers makes this technique particularly appealing for fabrication of 3-D scaffolds for tissue engineering. PMID:23729598

  10. Arthroscopic fixation of cell free polymer-based cartilage implants with a bioinspired polymer surface on the hip joint: a cadaveric pilot study.

    PubMed

    Lahner, Matthias; Duif, Christian; Ficklscherer, Andreas; Kaps, Christian; Kalwa, Lukas; Seidl, Tobias

    2014-01-01

    This study investigates the adhesion capacity of a polyglycolic acid- (PGA-) hyaluronan scaffold with a structural modification based on a planar polymer (PM) surface in a cadaver cartilage defect model. Two cadaver specimens were used to serially test multiple chondral matrices. In a cadaver hip model, cell free polymer-based cartilage implants with a planar bioinspired PM surface (PGA-PM-scaffolds) were implanted arthroscopically on 10 mm × 15 mm full-thickness femoral hip cartilage lesions. Unprocessed cartilage implants without a bioinspired PM surface were used as control group. The cartilage implants were fixed without and with the use of fibrin glue on femoral hip cartilage defects. After 50 movement cycles and removal of the distraction, a rearthroscopy was performed to assess the outline attachment and integrity of the scaffold. The fixation techniques without and with fibrin fixation showed marginal differences for outline attachment, area coverage, scaffold integrity, and endpoint fixation after 50 cycles. The PGA-PM-scaffolds with fibrin fixation achieved a higher score in terms of the attachment, integrity, and endpoint fixation than the PGA-scaffold on the cartilage defect. Relating to the outline attachment, area coverage, scaffold integrity, and endpoint fixation, the fixation with PGA-PM-scaffolds accomplished significantly better results compared to the PGA-scaffolds (P = 0.03752, P = 0.03078, P = 0.00512, P = 0.00512). PGA-PM-scaffolds demonstrate increased observed initial fixation strength in cadaver femoral head defects relative to PGA-scaffold, particularly when fibrin glue is used for fixation.

  11. Arthroscopic Fixation of Cell Free Polymer-Based Cartilage Implants with a Bioinspired Polymer Surface on the Hip Joint: A Cadaveric Pilot Study

    PubMed Central

    Lahner, Matthias; Duif, Christian; Ficklscherer, Andreas; Kaps, Christian; Kalwa, Lukas; Seidl, Tobias

    2014-01-01

    This study investigates the adhesion capacity of a polyglycolic acid- (PGA-) hyaluronan scaffold with a structural modification based on a planar polymer (PM) surface in a cadaver cartilage defect model. Two cadaver specimens were used to serially test multiple chondral matrices. In a cadaver hip model, cell free polymer-based cartilage implants with a planar bioinspired PM surface (PGA-PM-scaffolds) were implanted arthroscopically on 10 mm × 15 mm full-thickness femoral hip cartilage lesions. Unprocessed cartilage implants without a bioinspired PM surface were used as control group. The cartilage implants were fixed without and with the use of fibrin glue on femoral hip cartilage defects. After 50 movement cycles and removal of the distraction, a rearthroscopy was performed to assess the outline attachment and integrity of the scaffold. The fixation techniques without and with fibrin fixation showed marginal differences for outline attachment, area coverage, scaffold integrity, and endpoint fixation after 50 cycles. The PGA-PM-scaffolds with fibrin fixation achieved a higher score in terms of the attachment, integrity, and endpoint fixation than the PGA-scaffold on the cartilage defect. Relating to the outline attachment, area coverage, scaffold integrity, and endpoint fixation, the fixation with PGA-PM-scaffolds accomplished significantly better results compared to the PGA-scaffolds (P = 0.03752, P = 0.03078, P = 0.00512, P = 0.00512). PGA-PM-scaffolds demonstrate increased observed initial fixation strength in cadaver femoral head defects relative to PGA-scaffold, particularly when fibrin glue is used for fixation. PMID:25247185

  12. A Blinded, Randomised, Controlled Trial of Stapled Versus Tissue Glue Closure of Neck Surgery Incisions

    PubMed Central

    Ridgway, DM; Mahmood, F; Moore, L; Bramley, D; Moore, PJ

    2007-01-01

    INTRODUCTION Cosmetic acceptability of scar and neck mobility are important outcomes after collar line incision for neck surgery. This randomised, controlled trial compares these parameters in closures using tissue glue (Dermabond™, Ethicon, UK) and skin staples. PATIENTS AND METHODS Patients requiring a collar line incision were randomised to receiving tissue glue or staples for skin closure. Time for closure to be completed was recorded. Mobility of the neck was assessed using a visual analogue scale at 48 h and 1 week after surgery. At 6 weeks, cosmetic appearance was assessed using a linear 1–10 visual analogue scale by the patient, surgeon and an independent blinded assessor. Results were compared using appropriate statistical tests. RESULTS Glued (n = 14) and stapled (n = 15) closures were performed for hemithyroidectomy (n = 8 versus 6), sub-total thyroidectomy (n = 2 versus 4), total thyroidectomy (n = 1 versus 4) and parathyroidectomy (n = 3 versus 1). Closure with tissue glue took significantly longer than with staples (mean, 95 versus 28 s; P < 0.001). Neck mobility scores were comparable at 48 h and 1 week (mean, 4.8 versus 4.4; P = 0.552: and 2.7 versus 2.6; P = 0.886). Cosmetic appearance at 6 weeks was comparable when patient (mean, 1.7 versus 1.8; P = 0.898), surgeon (mean, 2.6 versus 2.3; P = 0.633) and independent assessment (mean, 1.4 versus 1.9; P = 0.365) was performed. CONCLUSIONS The use of glued skin closure may increase the duration of surgery but acceptable neck mobility and wound cosmesis can be achieved by the more rapid application of stapled skin closure in cervicotomy incisions. PMID:17394707

  13. Neuronal Networks on Nanocellulose Scaffolds.

    PubMed

    Jonsson, Malin; Brackmann, Christian; Puchades, Maja; Brattås, Karoline; Ewing, Andrew; Gatenholm, Paul; Enejder, Annika

    2015-11-01

    Proliferation, integration, and neurite extension of PC12 cells, a widely used culture model for cholinergic neurons, were studied in nanocellulose scaffolds biosynthesized by Gluconacetobacter xylinus to allow a three-dimensional (3D) extension of neurites better mimicking neuronal networks in tissue. The interaction with control scaffolds was compared with cationized nanocellulose (trimethyl ammonium betahydroxy propyl [TMAHP] cellulose) to investigate the impact of surface charges on the cell interaction mechanisms. Furthermore, coatings with extracellular matrix proteins (collagen, fibronectin, and laminin) were investigated to determine the importance of integrin-mediated cell attachment. Cell proliferation was evaluated by a cellular proliferation assay, while cell integration and neurite propagation were studied by simultaneous label-free Coherent anti-Stokes Raman Scattering and second harmonic generation microscopy, providing 3D images of PC12 cells and arrangement of nanocellulose fibrils, respectively. Cell attachment and proliferation were enhanced by TMAHP modification, but not by protein coating. Protein coating instead promoted active interaction between the cells and the scaffold, hence lateral cell migration and integration. Irrespective of surface modification, deepest cell integration measured was one to two cell layers, whereas neurites have a capacity to integrate deeper than the cell bodies in the scaffold due to their fine dimensions and amoeba-like migration pattern. Neurites with lengths of >50 μm were observed, successfully connecting individual cells and cell clusters. In conclusion, TMAHP-modified nanocellulose scaffolds promote initial cellular scaffold adhesion, which combined with additional cell-scaffold treatments enables further formation of 3D neuronal networks.

  14. Neuronal Networks on Nanocellulose Scaffolds.

    PubMed

    Jonsson, Malin; Brackmann, Christian; Puchades, Maja; Brattås, Karoline; Ewing, Andrew; Gatenholm, Paul; Enejder, Annika

    2015-11-01

    Proliferation, integration, and neurite extension of PC12 cells, a widely used culture model for cholinergic neurons, were studied in nanocellulose scaffolds biosynthesized by Gluconacetobacter xylinus to allow a three-dimensional (3D) extension of neurites better mimicking neuronal networks in tissue. The interaction with control scaffolds was compared with cationized nanocellulose (trimethyl ammonium betahydroxy propyl [TMAHP] cellulose) to investigate the impact of surface charges on the cell interaction mechanisms. Furthermore, coatings with extracellular matrix proteins (collagen, fibronectin, and laminin) were investigated to determine the importance of integrin-mediated cell attachment. Cell proliferation was evaluated by a cellular proliferation assay, while cell integration and neurite propagation were studied by simultaneous label-free Coherent anti-Stokes Raman Scattering and second harmonic generation microscopy, providing 3D images of PC12 cells and arrangement of nanocellulose fibrils, respectively. Cell attachment and proliferation were enhanced by TMAHP modification, but not by protein coating. Protein coating instead promoted active interaction between the cells and the scaffold, hence lateral cell migration and integration. Irrespective of surface modification, deepest cell integration measured was one to two cell layers, whereas neurites have a capacity to integrate deeper than the cell bodies in the scaffold due to their fine dimensions and amoeba-like migration pattern. Neurites with lengths of >50 μm were observed, successfully connecting individual cells and cell clusters. In conclusion, TMAHP-modified nanocellulose scaffolds promote initial cellular scaffold adhesion, which combined with additional cell-scaffold treatments enables further formation of 3D neuronal networks. PMID:26398224

  15. GlueX a new facility to search for gluonic degrees of freedom in mesons

    SciTech Connect

    Zihlmann, Benedikt

    2010-08-01

    The GlueX detector facility in Hall-D at Jefferson lab in Newport News is part of the 12 GeV upgrade and dedicated to the search for gluonic degrees of freedom in mesons by scattering high energy linearly polarized real photons of up to 9 GeV from nucleon targets. Civil construction of the Hall-D complex has started as well as the construction of the various detector components. The current status of the project is outlined here.

  16. Solvent constituents in paint, glue and thinner for plastic miniature hobby.

    PubMed

    Saito, J; Ikeda, M

    1988-07-01

    Solvent-containing products (8 paint, 29 glue and 4 thinner preparations) for plastic miniature hobby were analyzed for solvent constituents by capillary gas-chromatography. Acetone and methyl isobutyl ketone were two most extensively used solvents both in terms of frequency and concentration. Other popular solvents included ethyl alcohol and two esters of ethyl acetate and butyl acetate. In contrast, aromatics, chlorinated hydrocarbons and ethylene glycol derivatives were seldomly detected. The present findings were discussed in comparison with the observation on the materials abused for sniffing in the past, as well as constituents in the products for industrial application. PMID:3176022

  17. Uncertainty and sensitivity assessments of an agricultural-hydrological model (RZWQM2) using the GLUE method

    NASA Astrophysics Data System (ADS)

    Sun, Mei; Zhang, Xiaolin; Huo, Zailin; Feng, Shaoyuan; Huang, Guanhua; Mao, Xiaomin

    2016-03-01

    Quantitatively ascertaining and analyzing the effects of model uncertainty on model reliability is a focal point for agricultural-hydrological models due to more uncertainties of inputs and processes. In this study, the generalized likelihood uncertainty estimation (GLUE) method with Latin hypercube sampling (LHS) was used to evaluate the uncertainty of the RZWQM-DSSAT (RZWQM2) model outputs responses and the sensitivity of 25 parameters related to soil properties, nutrient transport and crop genetics. To avoid the one-sided risk of model prediction caused by using a single calibration criterion, the combined likelihood (CL) function integrated information concerning water, nitrogen, and crop production was introduced in GLUE analysis for the predictions of the following four model output responses: the total amount of water content (T-SWC) and the nitrate nitrogen (T-NIT) within the 1-m soil profile, the seed yields of waxy maize (Y-Maize) and winter wheat (Y-Wheat). In the process of evaluating RZWQM2, measurements and meteorological data were obtained from a field experiment that involved a winter wheat and waxy maize crop rotation system conducted from 2003 to 2004 in southern Beijing. The calibration and validation results indicated that RZWQM2 model can be used to simulate the crop growth and water-nitrogen migration and transformation in wheat-maize crop rotation planting system. The results of uncertainty analysis using of GLUE method showed T-NIT was sensitive to parameters relative to nitrification coefficient, maize growth characteristics on seedling period, wheat vernalization period, and wheat photoperiod. Parameters on soil saturated hydraulic conductivity, nitrogen nitrification and denitrification, and urea hydrolysis played an important role in crop yield component. The prediction errors for RZWQM2 outputs with CL function were relatively lower and uniform compared with other likelihood functions composed of individual calibration criterion. This

  18. Lifetime Improvement of Organic Light Emitting Diodes using LiF Thin Film and UV Glue Encapsulation

    NASA Astrophysics Data System (ADS)

    Huang, Jian-Ji; Su, Yan-Kuin; Chang, Ming-Hua; Hsieh, Tsung-Eong; Huang, Bohr-Ran; Wang, Shun-Hsi; Chen, Wen-Ray; Tsai, Yu-Sheng; Hsieh, Huai-En; Liu, Mark O.; Juang, Fuh-Shyang

    2008-07-01

    This work demonstrates the use of lithium fluoride (LiF) as a passivation layer and a newly developed UV glue for encapsulation on the LiF passivation layer to enhance the stability of organic light-emitting devices (OLEDs). Devices with double protective layers showed a 25-fold increase in operational lifetime compared to those without any packaging layers. LiF has a low melting point and insulating characteristics and it can be adapted as both a protective layer and pre-encapsulation film. The newly developed UV glue has a fast curing time of only 6 s and can be directly spin-coated onto the surface of the LiF passivation layer. The LiF thin film plus spin-coated UV glue is a simple packaging method that reduces the fabrication costs of OLEDs.

  19. Ultrastructural characteristics of fibrin clots from canine and feline platelet concentrates activated with calcium gluconate or calcium gluconate plus batroxobin

    PubMed Central

    2013-01-01

    Background The aim of this study was to use transmission electron microscopy to describe the ultrastructural characteristics of clots obtained from canine and feline platelet concentrates (PC) that had been activated with calcium gluconate (CG) or CG plus batroxobin (CGB). Platelets from fibrin clots were classified according their morphological changes. The area of the intercellular space (μm2), the area of the fibrin fibers (μm2), and the width of the fibrin fibers (μm) were determined for the dog clots. The platelet area (μm2), the area of fibrin fibers (μm2), the ratio of the minor and major axes of platelets, the ratio of the major and minor axes of platelets, and the number of α-granules found within platelets were measured for the cat clots. Results Cat platelets displayed full activation. Dog platelets displayed lysis with loss of normal architecture. In both species, a statistically significant difference was found (P < 0.01) between the fibrin fiber measurements in the PC clots activated with CG and CGB. Conclusions The findings suggest that activation with CG caused platelet alpha granules to release their contents. In cats, fibrin production was greater when the PC was activated with CG. In dogs, activation with CG produced thick fibrin fibers. PMID:23587176

  20. Long-Standing Motor and Sensory Recovery following Acute Fibrin Sealant Based Neonatal Sciatic Nerve Repair.

    PubMed

    Perussi Biscola, Natalia; Politti Cartarozzi, Luciana; Ferreira Junior, Rui Seabra; Barraviera, Benedito; Leite Rodrigues de Oliveira, Alexandre

    2016-01-01

    Brachial plexus lesion results in loss of motor and sensory function, being more harmful in the neonate. Therefore, this study evaluated neuroprotection and regeneration after neonatal peripheral nerve coaptation with fibrin sealant. Thus, P2 neonatal Lewis rats were divided into three groups: AX: sciatic nerve axotomy (SNA) without treatment; AX+FS: SNA followed by end-to-end coaptation with fibrin sealant derived from snake venom; AX+CFS: SNA followed by end-to-end coaptation with commercial fibrin sealant. Results were analyzed 4, 8, and 12 weeks after lesion. Astrogliosis, microglial reaction, and synapse preservation were evaluated by immunohistochemistry. Neuronal survival, axonal regeneration, and ultrastructural changes at ventral spinal cord were also investigated. Sensory-motor recovery was behaviorally studied. Coaptation preserved synaptic covering on lesioned motoneurons and led to neuronal survival. Reactive gliosis and microglial reaction decreased in the same groups (AX+FS, AX+CFS) at 4 weeks. Regarding axonal regeneration, coaptation allowed recovery of greater number of myelinated fibers, with improved morphometric parameters. Preservation of inhibitory synaptic terminals was accompanied by significant improvement in the motor as well as in the nociceptive recovery. Overall, the present data suggest that acute repair of neonatal peripheral nerves with fibrin sealant results in neuroprotection and regeneration of motor and sensory axons. PMID:27446617

  1. Mast cells contribute to fibrin deposition in reverse passive Arthus reaction in mouse skin.

    PubMed

    Ramos, B F; Zhang, Y; Jakschik, B A

    1992-09-01

    The activation of the clotting system is an important process during inflammation to contain the injury and initiate tissue repair. In the present study, we investigated the effect of mast cells on fibrin deposition in reverse passive Arthus reaction in mast cell-deficient WBB6F1-W/Wv(W/Wv) and control WBB6F1-(+)/+(+/+) mice, that were given 125I-labeled fibrogen intravenousty. An antibody dose-dependent increase in radioactivity was observed in the challenged skin sites. Sequential water and urea extractions characterized the radioiodinated fibrinogen derivatives present in the tissue. The radioactivity found in the various fractions of the stimulated samples from +/+ was 2-10-fold higher than that in specimens from W/Wv mice. The greatest difference was observed in the urea-insoluble pellet (cross-linked fibrin and its early degradation products). Reconstitution of W/Wv mice with mast cells augmented the response to levels similar to those in +/+ mice. Pretreatment with the antihistamine pyrilamine blocked the accumulation of 125I-labeled fibrinogen and its derivatives by approximately 70% in +/+ but not in W/Wv mice. Inhibition of leukotriene synthesis by A-63162 markedly decreased the accumulation of iodinated fibrinogen in both +/+ and W/Wv mice. The data suggest that mast cells and their vasoactive mediator histamine contribute to the exudation of clotting factors, which results in fibrin deposition and that mast cells also enhance fibrin cross-linkage.

  2. Modelling of platelet-fibrin clot formation in flow with a DPD-PDE method.

    PubMed

    Tosenberger, A; Ataullakhanov, F; Bessonov, N; Panteleev, M; Tokarev, A; Volpert, V

    2016-02-01

    The paper is devoted to mathematical modelling of clot growth in blood flow. Great complexity of the hemostatic system dictates the need of usage of the mathematical models to understand its functioning in the normal and especially in pathological situations. In this work we investigate the interaction of blood flow, platelet aggregation and plasma coagulation. We develop a hybrid DPD-PDE model where dissipative particle dynamics (DPD) is used to model plasma flow and platelets, while the regulatory network of plasma coagulation is described by a system of partial differential equations. Modelling results confirm the potency of the scenario of clot growth where at the first stage of clot formation platelets form an aggregate due to weak inter-platelet connections and then due to their activation. This enables the formation of the fibrin net in the centre of the platelet aggregate where the flow velocity is significantly reduced. The fibrin net reinforces the clot and allows its further growth. When the clot becomes sufficiently large, it stops growing due to the narrowed vessel and the increase of flow shear rate at the surface of the clot. Its outer part is detached by the flow revealing the inner part covered by fibrin. This fibrin cap does not allow new platelets to attach at the high shear rate, and the clot stops growing. Dependence of the final clot size on wall shear rate and on other parameters is studied.

  3. Platelet-rich fibrin in treatment of periapical lesions: a novel therapeutic option.

    PubMed

    Shubhashini, N; Kumar, R Vinaya; Shija, A S; Razvi, Shuaib

    2013-01-01

    In the present case of a 35-year old patient, platelet-rich fibrin, which is an autologous platelet concentrate, was used to fill the osseous defect following surgery. The case was assessed both clinically and radiographically for a period of 9 months. PMID:23878831

  4. Fundamental Investigations of the Extracellular Proteins Fibrin and Collagen in Microchannel Devices

    NASA Astrophysics Data System (ADS)

    Evans, Heather M.; Koester, Sarah; Pfohl, Thomas

    2007-03-01

    Microfluidic structures are particularly amenable to controlled investigations of protein bundle and network formation. Hydrodynamic focusing is utilized to create a diffusion-controlled gradient of reactants, enabling non-equilibrium investigations. We present studies of the blood clotting protein fibrin, a three-dimensional network formed from the enzymatic cleavage of fibrinogen monomers by the protein thrombin. Fibrin is a vital component of blood clots, and has been implicated in a variety of diseases. Real-time fluorescence microscopy and x-ray micro-diffraction are used to quantify supramolecular assembly and provide snapshots of the evolution of fibrin network formation. We also show that collagen, a ubiquitous extracellular protein, can be bundled in situ through the use of a pH gradient. An outlook toward artificial blood vessels arises from the insight that both fibrin and collagen can easily be used to coat microchannel structures. The resulting mesh forms an ideal environment for red blood cells and other cell types.

  5. Preliminary results of using a commercial fibrin sealant in the treatment of fistula-in-ano.

    PubMed

    Chan, K M; Lau, C W; Lai, K K T; Auyeung, M C; Ho, L S; Luk, H T; Lo, K H

    2002-02-01

    A prospective non-randomised study fibrin sealant injection to manage patients with fistula-in-ano, with magnetic resonance imaging (MRI) monitoring, was performed during the period 5/6/1999 to 28/2/2000. The aim was to determine whether a fibrin sealant could be used as a treatment modality for anorectal fistula and the usefulness of MRI perineum to monitor the disease activity. Ten patients were included in the study. Mean age was 47 years (range 7 months to 70 years). Male: female ratio was 9:1. Mean follow-up duration was 26.4 weeks. The overall success rate was 60%. The success rate of different fistula types were different (60%, 0%, 100% for intersphincteric, transphincteric, subcutaneous, respectively). Variable decrease in signal on STIR images and contrast enhancement was noted in the patients with successful and failure of fibrin sealant injection. In conclusion, fibrin sealant injection is a useful alternative treatment in the management of fistula-in-ano. MRI is helpful in delineating the anatomy of fistula-in-ano but not a useful tool to follow-up disease activity. PMID:11878300

  6. Supplementation of fibrin gels with sodium chloride enhances physical properties and ensuing osteogenic response.

    PubMed

    Davis, H E; Miller, S L; Case, E M; Leach, J K

    2011-02-01

    Modifying the relative concentrations of fibrinogen and thrombin can control the physical properties of fibrin gels, while the viability of associated cells has been linked to the gel's final network structure. It was hypothesized that increasing the gel ionic strength during fabrication through supplementation with sodium chloride (NaCl) would provide an improved approach for tailoring the physical properties of fibrin gels and maintaining the viability and osteogenic potential of entrapped cells. Fibrin gels were formed by mixing fibrinogen, thrombin and calcium chloride with varying masses of NaCl (0-4.40% w/v), and the osteogenic potential of entrapped human mesenchymal stem cells (MSC) was examined over 14 days. Physical properties including gelation time, compressive modulus and fiber diameter were dependent upon NaCl content, with gels containing 2.60% NaCl possessing compressive moduli threefold higher than gels without NaCl. Alkaline phosphatase activity was highest for MSC entrapped in gels containing 2.15-2.60% NaCl after 14 days, and all gels exhibited increased calcium incorporation over the culture period. These data confirm that varying the salt concentration of the pre-gel solution can modulate the material properties of fibrin constructs without additional fibrinogen or thrombin, thereby offering a new approach for generating improved cell transplantation vehicles for use in bone tissue regeneration.

  7. Long-Standing Motor and Sensory Recovery following Acute Fibrin Sealant Based Neonatal Sciatic Nerve Repair

    PubMed Central

    Ferreira Junior, Rui Seabra

    2016-01-01

    Brachial plexus lesion results in loss of motor and sensory function, being more harmful in the neonate. Therefore, this study evaluated neuroprotection and regeneration after neonatal peripheral nerve coaptation with fibrin sealant. Thus, P2 neonatal Lewis rats were divided into three groups: AX: sciatic nerve axotomy (SNA) without treatment; AX+FS: SNA followed by end-to-end coaptation with fibrin sealant derived from snake venom; AX+CFS: SNA followed by end-to-end coaptation with commercial fibrin sealant. Results were analyzed 4, 8, and 12 weeks after lesion. Astrogliosis, microglial reaction, and synapse preservation were evaluated by immunohistochemistry. Neuronal survival, axonal regeneration, and ultrastructural changes at ventral spinal cord were also investigated. Sensory-motor recovery was behaviorally studied. Coaptation preserved synaptic covering on lesioned motoneurons and led to neuronal survival. Reactive gliosis and microglial reaction decreased in the same groups (AX+FS, AX+CFS) at 4 weeks. Regarding axonal regeneration, coaptation allowed recovery of greater number of myelinated fibers, with improved morphometric parameters. Preservation of inhibitory synaptic terminals was accompanied by significant improvement in the motor as well as in the nociceptive recovery. Overall, the present data suggest that acute repair of neonatal peripheral nerves with fibrin sealant results in neuroprotection and regeneration of motor and sensory axons. PMID:27446617

  8. Mechanical Stability and Fibrinolytic Resistance of Clots Containing Fibrin, DNA, and Histones*

    PubMed Central

    Longstaff, Colin; Varjú, Imre; Sótonyi, Péter; Szabó, László; Krumrey, Michael; Hoell, Armin; Bóta, Attila; Varga, Zoltán; Komorowicz, Erzsébet; Kolev, Krasimir

    2013-01-01

    Neutrophil extracellular traps are networks of DNA and associated proteins produced by nucleosome release from activated neutrophils in response to infection stimuli and have recently been identified as key mediators between innate immunity, inflammation, and hemostasis. The interaction of DNA and histones with a number of hemostatic factors has been shown to promote clotting and is associated with increased thrombosis, but little is known about the effects of DNA and histones on the regulation of fibrin stability and fibrinolysis. Here we demonstrate that the addition of histone-DNA complexes to fibrin results in thicker fibers (increase in median diameter from 84 to 123 nm according to scanning electron microscopy data) accompanied by improved stability and rigidity (the critical shear stress causing loss of fibrin viscosity increases from 150 to 376 Pa whereas the storage modulus of the gel increases from 62 to 82 pascals according to oscillation rheometric data). The effects of DNA and histones alone are subtle and suggest that histones affect clot structure whereas DNA changes the way clots are lysed. The combination of histones + DNA significantly prolongs clot lysis. Isothermal titration and confocal microscopy studies suggest that histones and DNA bind large fibrin degradation products with 191 and 136 nm dissociation constants, respectively, interactions that inhibit clot lysis. Heparin, which is known to interfere with the formation of neutrophil extracellular traps, appears to prolong lysis time at a concentration favoring ternary histone-DNA-heparin complex formation, and DNase effectively promotes clot lysis in combination with tissue plasminogen activator. PMID:23293023

  9. Simultaneous sinus lift and implantation using platelet-rich fibrin as sole grafting material.

    PubMed

    Jeong, Seung-Mi; Lee, Chun-Ui; Son, Jeong-Seog; Oh, Ji-Hyeon; Fang, Yiqin; Choi, Byung-Ho

    2014-09-01

    Recently, several authors have shown that simultaneous sinus lift and implantation using autologous platelet-rich fibrin as the sole filling material is a reliable procedure promoting bone augmentation in the maxillary sinus. The aim of this study was to examine the effect of simultaneous sinus lift and implantation using platelet-rich fibrin as the sole grafting material on bone formation in a canine sinus model. An implant was placed after sinus membrane elevation in the maxillary sinus of six adult female mongrel dogs. The resulting space between the membrane and sinus floor was filled with autologous platelet-rich fibrin retrieved from each dog. The implants were left in place for six months. Bone tissue was seen at the lower part of the implants introduced into the sinus cavity. The height of the newly formed bone around the implants ranged from 0 mm to 4.9 mm (mean; 2.6 ± 2.0 mm) on the buccal side and from 0 mm to 4.2 mm (mean; 1.3 ± 1.8 mm) on the palatal side. The findings from this study suggest that simultaneous sinus lift and implantation using platelet-rich fibrin as sole grafting material is not a predictable and reproducible procedure, especially with respect to the bone formation around the implants in the sinus cavity.

  10. Platelet-rich fibrin matrix improves wound angiogenesis via inducing endothelial cell proliferation.

    PubMed

    Roy, Sashwati; Driggs, Jason; Elgharably, Haytham; Biswas, Sabyasachi; Findley, Muna; Khanna, Savita; Gnyawali, Urmila; Bergdall, Valerie K; Sen, Chandan K

    2011-11-01

    The economic, social, and public health burden of chronic ulcers and other compromised wounds is enormous and rapidly increasing with the aging population. The growth factors derived from platelets play an important role in tissue remodeling including neovascularization. Platelet-rich plasma (PRP) has been utilized and studied for the last four decades. Platelet gel and fibrin sealant, derived from PRP mixed with thrombin and calcium chloride, have been exogenously applied to tissues to promote wound healing, bone growth, hemostasis, and tissue sealing. In this study, we first characterized recovery and viability of as well as growth factor release from platelets in a novel preparation of platelet gel and fibrin matrix, namely platelet-rich fibrin matrix (PRFM). Next, the effect of PRFM application in a delayed model of ischemic wound angiogenesis was investigated. The study, for the first time, shows the kinetics of the viability of platelet-embedded fibrin matrix. A slow and steady release of growth factors from PRFM was observed. The vascular endothelial growth factor released from PRFM was primarily responsible for endothelial mitogenic response via extracellular signal-regulated protein kinase activation pathway. Finally, this preparation of PRFM effectively induced endothelial cell proliferation and improved wound angiogenesis in chronic wounds, providing evidence of probable mechanisms of action of PRFM in healing of chronic ulcers.

  11. A Comparison of the Mechanical and Structural Properties of Fibrin Fibers with Other Protein Fibers

    PubMed Central

    Guthold, M.; Liu, W.; Sparks, E. A.; Jawerth, L. M.; Peng, L.; Falvo, M.; Superfine, R.; Hantgan, R. R.; Lord, S. T.

    2010-01-01

    In the past few years a great deal of progress has been made in studying the mechanical and structural properties of biological protein fibers. Here, we compare and review the stiffness (Young's modulus, E) and breaking strain (also called rupture strain or extensibility, εmax) of numerous biological protein fibers in light of the recently reported mechanical properties of fibrin fibers. Emphasis is also placed on the structural features and molecular mechanisms that endow biological protein fibers with their respective mechanical properties. Generally, stiff biological protein fibers have a Young's modulus on the order of a few Gigapascal and are not very extensible (εmax < 20%). They also display a very regular arrangement of their monomeric units. Soft biological protein fibers have a Young's modulus on the order of a few Megapascal and are very extensible (εmax > 100%). These soft, extensible fibers employ a variety of molecular mechanisms, such as extending amorphous regions or unfolding protein domains, to accommodate large strains. We conclude our review by proposing a novel model of how fibrin fibers might achieve their extremely large extensibility, despite the regular arrangement of the monomeric fibrin units within a fiber. We propose that fibrin fibers accommodate large strains by two major mechanisms: (1) an α-helix to β-strand conversion of the coiled coils; (2) a partial unfolding of the globular C-terminal domain of the γ-chain. PMID:17952642

  12. Therapeutic assessment of mesenchymal stem cells delivered within a PEGylated fibrin gel following an ischemic injury.

    PubMed

    Ricles, Laura M; Hsieh, Pei-Ling; Dana, Nicholas; Rybalko, Viktoriya; Kraynak, Chelsea; Farrar, Roger P; Suggs, Laura J

    2016-09-01

    The intent of the current study was to investigate the therapeutic contribution of MSCs to vascular regeneration and functional recovery of ischemic tissue. We used a rodent hind limb ischemia model and intramuscularly delivered MSCs within a PEGylated fibrin gel matrix. Within this model, we demonstrated that MSC therapy, when delivered in PEGylated fibrin, results in significantly higher mature blood vessel formation, which allows for greater functional recovery of skeletal muscle tissue as assessed using force production measurements. We observed initial signs of vascular repair at early time points when MSCs were delivered without PEGylated fibrin, but this did not persist or lead to recovery of the tissue in the long-term. Furthermore, animals which were treated with PEGylated fibrin alone exhibited a greater number of mature blood vessels, but they did not arterialize and did not show improvements in force production. These results demonstrate that revascularization of ischemic tissue may be a necessary but not sufficient step to complete functional repair of the injured tissue. This work has implications on stem cell therapies for ischemic diseases and also potentially on how such therapies are evaluated. PMID:27318932

  13. Bioresorbable scaffolds on the bench.

    PubMed

    Ormiston, John; Motreff, Pascal; Darremont, Olivier; Webber, Bruce; Guerin, Patrice; Webster, Mark

    2015-01-01

    Bioresorbable scaffolds (BRS) in bifurcations have all of the potential advantages of BRS in non-bifurcating lesions and, in addition, the absorption of side branch (SB) ostial struts may at least partially release the branch from "jail". Polymeric BRS struts may break when post-dilated beyond their safe limits and multiple fractures may lead to adverse clinical events. Bench testing provides insights into the behaviour of different BRS in bifurcations and helps the interventional cardiologist to choose, deliver and post-dilate appropriately. Bench testing of polymeric BRS must be in a water bath at 37ºC as polymer performance is temperature sensitive. Balloon dilatation through the side of a BRS or a durable metallic stent causes distortion corrected by mini-kissing balloon post-dilatation (mini-KBPD) where the SB balloon extends only a short distance into the main branch (MB), limiting the length of MB scaffold exposed to the inflation of two balloons. The safe pressure threshold for SB dilatation of a 3.0 mm Absorb scaffold with a 3.0 mm non-compliant balloon is 10 atm and for mini-KBPD with two 3.0 mm balloons it is 5 atm. Strategies such as culotte, crush and simultaneous kissing scaffolds (SKS) may not be appropriate for the current Absorb scaffold. PMID:25983158

  14. Osteogenic Scaffolds for Bone Reconstruction

    PubMed Central

    Li, Ling-jiang; Liu, Ning; Liu, Qing; Jia, Lian-shun; Yuan, Wen

    2012-01-01

    Abstract A highly osteogenic hybrid bioabsorbable scaffold was developed for bone reconstruction/augmentation. Through the use of a solid free-form fabrication technology, a bioabsorbable polycaprolactone (PCL) cage scaffold with a desired size and shape was produced and then filled with osteogenic bone graft particles, that is, morselized autologous bone chips. A rabbit total lamina defect model was chosen to demonstrate its efficacy in regenerating bone with a complicated anatomic shape. Both iliac bone and morselized iliac bone grafts were used in this study for comparison purposes. Serum osteocalcin and collagen type I cross-linked C-terminal telopeptide (CTx) determination showed that active bone remodeling occurred after bone grafts were implanted. X-ray images showed that the bony defects were completely filled with bone mass in all the groups with bone grafts. However, biomechanical tests showed that only the iliac bone and hybrid scaffold groups could restore the mechanical properties to the normal level after 10 weeks of implantation. A histology study showed that both iliac and hybrid scaffold groups had extensive new bone formation, and no adhesion and fibrosis were found. These results indicated that this osteogenic hybrid scaffold can be a good alternative to autologous iliac bone, because it does not need a second iliac bone-harvesting surgery, and thus the morbidity and the possible infections that are often associated with the bone harvesting surgery can be avoided. PMID:23515416

  15. Recombinant factor VIIa enhances platelet deposition from flowing haemophilic blood but requires the contact pathway to promote fibrin deposition.

    PubMed

    Li, R; Panckeri, K A; Fogarty, P F; Diamond, S L

    2015-03-01

    In prior microfluidic studies with haemophilic blood perfused over collagen, we found that a severe deficiency (<1% factor level) reduced platelet and fibrin deposition, while a moderate deficiency (1-5%) only reduced fibrin deposition. We investigated: (i) the differential effect of rFVIIa (0.04-20 nm) on platelet and fibrin deposition, and (ii) the contribution of the contact pathway to rFVIIa-induced haemophilic blood clotting. Haemophilic or healthy blood with low and high corn trypsin inhibitor (CTI, 4 or 40 μg mL(-1) ) was perfused over collagen at an initial venous wall shear rate of 100 s(-1) . At 100 s(-1) wall shear rate, where FXIIa leads to thrombin production without added tissue factor, FXI-deficient blood (3%) or severely FVIII-deficient blood (<1%) produced no fibrin at either CTI level. Whereas rFVIIa potently enhanced platelet deposition, fibrin generation was not rescued. Distinct from the high CTI condition, engagement of the contact pathway (low CTI) in moderately FVIII-deficient (3%) or moderately FIX-deficient blood (5%) resulted in enhanced platelet and fibrin deposition following 4 nm rFVIIa supplementation. In mildly FVIII-deficient blood (15%) at <24 h since haemostatic therapy, rFVIIa enhanced both platelet and fibrin generation in either CTI condition although fibrin was produced more quickly and abundantly in low CTI. For tissue factor-free conditions of severe haemophilic blood clotting, we conclude that rFVIIa reliably generates low levels of 'signaling' thrombin sufficient to enhance platelet deposition on collagen, but is insufficient to drive fibrin polymerization unless potentiated by the contact pathway.

  16. Fibrin matrices enhance the transplant and efficacy of cytotoxic stem cell therapy for post-surgical cancer.

    PubMed

    Bagó, Juli R; Pegna, Guillaume J; Okolie, Onyi; Hingtgen, Shawn D

    2016-04-01

    Tumor-homing cytotoxic stem cell (SC) therapy is a promising new approach for treating the incurable brain cancer glioblastoma (GBM). However, problems of retaining cytotoxic SCs within the post-surgical GBM resection cavity are likely to significantly limit the clinical utility of this strategy. Here, we describe a new fibrin-based transplant approach capable of increasing cytotoxic SC retention and persistence within the resection cavity, yet remaining permissive to tumoritropic migration. This fibrin-based transplant can effectively treat both solid and post-surgical human GBM in mice. Using our murine model of image-guided model of GBM resection, we discovered that suspending human mesenchymal stem cells (hMSCS) in a fibrin matrix increased initial retention in the surgical resection cavity 2-fold and prolonged persistence in the cavity 3-fold compared to conventional delivery strategies. Time-lapse motion analysis revealed that cytotoxic hMSCs in the fibrin matrix remain tumoritropic, rapidly migrating from the fibrin matrix to co-localize with cultured human GBM cells. We encapsulated hMSCs releasing the cytotoxic agent TRAIL (hMSC-sTR) in fibrin, and found hMSC-sTR/fibrin therapy reduced the viability of multiple 3-D human GBM spheroids and regressed established human GBM xenografts 3-fold in 11 days. Mimicking clinical therapy of surgically resected GBM, intra-cavity seeding of therapeutic hMSC-sTR encapsulated in fibrin reduced post-surgical GBM volumes 6-fold, increased time to recurrence 4-fold, and prolonged median survival from 15 to 36 days compared to control-treated animals. Fibrin-based SC therapy could represent a clinically compatible, viable treatment to suppress recurrence of post-surgical GBM and other lethal cancer types.

  17. Fibrin-mediated integrin signaling plays a critical role in hepatic regeneration after partial hepatectomy in mice

    PubMed Central

    Beier, Juliane I.; Guo, Luping; Joshi-Barve, Swati; Ritzenthaler, Jeffrey D.; Roman, Jesse; Arteel, Gavin E.

    2016-01-01

    Background The regenerative capacity of the liver is critical for proper responses to injury. Fibrin extracellular matrix (ECM) deposition is a common response to insult and contributes to inflammatory liver injury. However, the role of this matrix in hepatic regeneration has not been determined. Objective The purpose of this study was first to determine the role of fibrin ECM in hepatic regeneration followed by the role of the fibrin-binding αvβ3 integrin in mediating this effect. Material and methods C57BI/6J (WT) or PAI-1 knockout (KO) mice underwent 70% partial hepatectomy (PHx); plasma and histologic indices of regeneration were determined, as well as expression of key genes involved in hepatic regeneration. Results PHx promoted transient fibrin deposition by activating coagulation and concomitantly decreasing fibrinolysis. Inhibiting fibrin deposition, either by blocking thrombin (hirudin) in WT mice or by knocking out PAI-1, was associated with a decrease in hepatocyte proliferation after PHx. This strongly suggested a role for fibrin ECM in liver regeneration. To investigate if αvβ3 integrin mediates this action, we tested the effects of the anti-αvβ3 cyclic peptide RGDfV in animals after PHx. As was observed with inhibition of fibrin deposition, competitive inhibition of αvβ3 integrin delayed regeneration after PHx, while not affecting fibrin deposition. These effects of RGDfV correlated with impaired angiogenesis and STAT3 signaling, as well as transient endothelial dysfunction. In conclusion, these data suggest that αvβ3 integrin plays an important role in coordinating hepatocyte division during liver regeneration after PHx via crosstalk with fibrin ECM. PMID:27493116

  18. Enhancing Interfacial Bonding between Anisotropically Oriented Grains Using a Glue-Nanofiller for Advanced Li-Ion Battery Cathode.

    PubMed

    Kim, Hyejung; Lee, Sanghan; Cho, Hyeon; Kim, Junhyeok; Lee, Jieun; Park, Suhyeon; Joo, Se Hun; Kim, Su Hwan; Cho, Yoon-Gyo; Song, Hyun-Kon; Kwak, Sang Kyu; Cho, Jaephil

    2016-06-01

    Formation of a glue-nanofiller layer between grains, consisting of a middle-temperature spinel-like Lix CoO2 phase, reinforces the strength of the incoherent interfacial binding between anisotropically oriented grains by enhancing the face-to-face adhesion strength. The cathode treated with the glue-layer exhibits steady cycling performance at both room-temperature and 60 °C. These results represent a step forward in advanced lithium-ion batteries via simple cathode coating. PMID:27074141

  19. 29 CFR 1910.28 - Safety requirements for scaffolding.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... requirements for scaffolding. (a) General requirements for all scaffolds. (1) Scaffolds shall be furnished and... § 1910.26. (2) The footing or anchorage for scaffolds shall be sound, rigid, and capable of carrying the... brick, or concrete blocks shall not be used to support scaffolds or planks. (3) (4) Scaffolds and...

  20. 29 CFR 1910.28 - Safety requirements for scaffolding.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... requirements for scaffolding. (a) General requirements for all scaffolds. (1) Scaffolds shall be furnished and... § 1910.26. (2) The footing or anchorage for scaffolds shall be sound, rigid, and capable of carrying the... brick, or concrete blocks shall not be used to support scaffolds or planks. (3) (4) Scaffolds and...

  1. 29 CFR 1910.28 - Safety requirements for scaffolding.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... requirements for scaffolding. (a) General requirements for all scaffolds. (1) Scaffolds shall be furnished and... 1910.26. (2) The footing or anchorage for scaffolds shall be sound, rigid, and capable of carrying the... brick, or concrete blocks shall not be used to support scaffolds or planks. (3) (4) Scaffolds and...

  2. 29 CFR 1910.28 - Safety requirements for scaffolding.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... requirements for scaffolding. (a) General requirements for all scaffolds. (1) Scaffolds shall be furnished and... § 1910.26. (2) The footing or anchorage for scaffolds shall be sound, rigid, and capable of carrying the... brick, or concrete blocks shall not be used to support scaffolds or planks. (3) (4) Scaffolds and...

  3. Development of fibrin-free intraocular lens with photochemical surface modification

    NASA Astrophysics Data System (ADS)

    Sato, Yuji; Tanizawa, Katsuya; Anai, Hiroyuki; Sato, Nobuhiro; Sato, Yuki; Ajiki, Tooru; Parel, Jean-Marie; Murahara, Masataka

    2004-07-01

    Having substituted the hydrophilic and hydrophobic groups alternately on the soft acrylic resin intraocular lens (IOL) surface by using an ArF excimer laser and a Xe2 excimer lamp, we have developed the IOL that is free from fibrin. Acrylic resin or PMMA lens has been used as an intraocular lens for 50 years. However, protein and fat are stuck onto the IOL surface after a long implantation, which opacifies the surface (after-cataract). Thus, we designed the micro domain structures of hydrophilic and hydrophobic groups on the IOL surface for fibrin-free. Firstly, the IOL was irradiated with the Xe2 excimer lamp in the presence of perfluoropolyether in order to make it hydrophobic. By this photochemical reaction, the CF3 functional groups were substituted on the IOL surface. Secondly, the ArF laser was projected on the IOL through the mask pattern in reduced size in the presence of water in order to be hydrophilic. With the photochemical reaction, the OH groups were substituted at the part exposed. The fibrin adsorption test of the modified IOL surface was carried out with FT-IR; which revealed that the fibrin-sticking rate of the treated sample has decreased by 23% compared with that of the non-treated sample. As a result, the fibrin-free IOL has been made by modifying the surface of the IOL to have the micro domain structures of the hydrophilic and hydrophobic groups that are arrayed alternately. In conclusion, the ideal intraocular lens has been demonstrated.

  4. Imaging Thromboembolism with Fibrin-Avid 99mTc-Peptide: Evaluation in Swine

    PubMed Central

    Aruva, Mohan R.; Daviau, Judy; Sharma, Shubh S.; Thakur, Mathew L.

    2006-01-01

    A pentapeptide, Gly-Pro-Arg-Pro-Pro, with high affinity for α-chain-fibrin was labeled with 99mTc (99mTc-TP850) and evaluated in swine to image experimental venous thromboembolism (deep vein thrombosis [DVT]) and pulmonary embolism (PE). Methods Scatchard analysis was performed to determine fibrin affinity for TP850 and the number of binding sites (receptors) per milligram of fibrin. DVT was induced in the left jugular vein and PE was induced by introducing a preformed autologous blood clot into the right atrium using a 7-French introducer sheath inserted into the right jugular vein. 99mTc-TP850 was injected at 4, 24, 48, 72, 96, or 120 h later. Animals were imaged for up to 4 h after injection, heparinized, and sacrificed. Lungs were extirpated, radiographed, and imaged, and the PE was removed. Other tissues, including blood and normal lungs, were harvested and, concomitantly, 99mTc was counted for determination of target-to-tissue ratios and the percentage injected dose per gram of tissue. Results The affinity for human fibrin was 10−9 mol/L and there were >1015 receptors per milligram of fibrin. DVT and PE were visualized for up to 4 h after injection with high DVT/blood (7.9–22.6), DVT/muscle (31.1–89.4), PE/blood (1–155), and PE/lung (0.8–245) ratios. Thereafter, the PEs fragmented spontaneously below the spatial resolution of the γ-camera and, despite the high associated radioactivity, could not be localized in vivo. The fragmented clots were detectable by scintigraphy on excised lungs and provided excellent concordance with radiograms. Conclusion 99mTc-TP850 with its modest affinity (10−9 mol/L), rapid blood clearance, and high DVT and PE uptake is a promising agent for imaging vascular thrombosis. PMID:16391200

  5. Inhibition of fibrin polymerization by fragment d is affected by calcium, Gly-Pro-Arg and Gly-His-Arg.

    PubMed

    Furlan, M; Rupp, C; Beck, E A

    1983-01-12

    Fibrinopeptides A and B were removed from purified human fibrinogen by bovine thrombin, whereas the snake venom protease batroxobin only split fibrinopeptide A from fibrinogen. Aggregation of the resulting desAB- and desA-fibrin monomers was evaluated by recording the turbidity of incubation mixtures. Fibrin assembly was strongly accelerated by increasing the calcium concentration from 10(-5) to 10(-3) M. Fragment D was obtained from fibrinogen by proteolytic degradation with plasmin in the presence of Ca2+. At a 4-fold molar concentration relative to fibrinogen, fragment D dramatically inhibited fibrin polymerization at up to 10(-4) M Ca2+. This anticlotting activity was, however, much less pronounced at 10(-3) M Ca2+. The thrombin clotting time, measured on human plasma, was prolonged by fragment D in a dose-dependent manner. In citrate-containing plasma, the fibrinogen clotting was significantly delayed by an equimolar concentration of fragment D. In barium sulfate-adsorbed oxalated plasma, containing 2.5 mM Ca2+, the same amount of fragment D hardly affected fibrin polymerization. We conclude that fragment D has no important anticlotting effect under physiological conditions. The synthetic peptide Gly-Pro-Arg, corresponding to the amino-terminal sequence of the fibrin alpha-chain, inhibited aggregation of both desA-fibrin and desAB-fibrin at 10(-3) M Ca2+. The inhibition of desAB-fibrin polymerization by Gly-Pro-Arg was abolished at 10(-5) M Ca2+. In addition, Gly-Pro-Arg depressed the anticlotting activity of fragment D at low calcium concentration. An analogue of the amino-terminus of fibrin beta-chain, Gly-His-Arg, strongly accelerated aggregation of desA-fibrin monomers, but only moderately enhanced polymerization of desAB-fibrin monomers at 10(-5) M Ca2+, both in the presence and in the absence of fragment D. This activating effect of Gly-His-Arg was abolished at 10(-3) M Ca2+. It is suggested that the binding of calcium, Gly-His-Arg, and possibly also Gly

  6. A first look at reconstructed data from the GlueX detector

    NASA Astrophysics Data System (ADS)

    Taylor, Simon; GlueX Collaboration

    2015-10-01

    Construction of the GlueX detector in Hall D at the Thomas Jefferson National Accelerator Facility has recently been completed as part of the 12 GeV Upgrade to the facility. The detector consists of a barrel region containing devices for tracking charged particles and a lead-scintillator calorimeter for detecting photons, and a forward region consisting of two layers of scintillator paddles for time-of-flight measurements and a lead-glass electromagnetic calorimeter. The electron beam from the accelerator is converted into a photon beam by inserting a diamond radiator, thereby producing a coherent bremsstrahlung spectrum of photons impinging on a 30 cm-long LH2 target. The energy of the photon beam is determined using a tagging spectrometer. A commissioning run took place in Spring of 2015 during which all of the detector components were read out. Preliminary calibrations have been determined to a level sufficient to allow reconstruction of final states with several charged tracks and neutral particles. A first look at results of reconstruction of events using the GlueX detector will be presented. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract DE-AC05-06OR23177.

  7. Calibrations for Charged Particle Tracking with the GlueX Detector

    NASA Astrophysics Data System (ADS)

    Staib, Michael; GlueX Collaboration

    2015-10-01

    Two gas detectors comprise the tracking system for the GlueX experiment, the Central Drift Chamber (CDC) and the Forward Drift Chamber (FDC). The CDC is a cylindrical straw-tube detector covering polar angles between 6° and 168°, delivering spatial resolution of ~150 μm. The FDC is a Cathode Strip Chamber consisting of four packages, each with six alternating layers of anode wires and cathode strips. The FDC is designed to track forward-going charged particles with polar angles between 1° and 20° with a spatial resolution of ~200 μm. Both tracking detectors record timing information and energy loss measurements useful for particle identification. During Fall 2014 and Spring 2015, the first photon beam was delivered on target for commissioning of the GlueX detector in Hall-D at Jefferson Lab. These data are currently being used in a large effort to calibrate the individual detector subsystems to achieve design performance. Methods and results for calibrations of each of the tracking detectors are presented. Techniques for alignment of the tracking system using a combination of cosmic rays and beam data is discussed. Finally, some early results of physics measurements including charged final-state particles are presented. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract DE-AC05-06OR23177.

  8. Equifinality of formal (DREAM) and informal (GLUE) bayesian approaches in hydrologic modeling?

    SciTech Connect

    Vrugt, Jasper A; Robinson, Bruce A; Ter Braak, Cajo J F; Gupta, Hoshin V

    2008-01-01

    In recent years, a strong debate has emerged in the hydrologic literature regarding what constitutes an appropriate framework for uncertainty estimation. Particularly, there is strong disagreement whether an uncertainty framework should have its roots within a proper statistical (Bayesian) context, or whether such a framework should be based on a different philosophy and implement informal measures and weaker inference to summarize parameter and predictive distributions. In this paper, we compare a formal Bayesian approach using Markov Chain Monte Carlo (MCMC) with generalized likelihood uncertainty estimation (GLUE) for assessing uncertainty in conceptual watershed modeling. Our formal Bayesian approach is implemented using the recently developed differential evolution adaptive metropolis (DREAM) MCMC scheme with a likelihood function that explicitly considers model structural, input and parameter uncertainty. Our results demonstrate that DREAM and GLUE can generate very similar estimates of total streamflow uncertainty. This suggests that formal and informal Bayesian approaches have more common ground than the hydrologic literature and ongoing debate might suggest. The main advantage of formal approaches is, however, that they attempt to disentangle the effect of forcing, parameter and model structural error on total predictive uncertainty. This is key to improving hydrologic theory and to better understand and predict the flow of water through catchments.

  9. Characteristics of S12045(X) photon sensors for GlueX

    NASA Astrophysics Data System (ADS)

    Smith, E. S.; Qiang, Y.; Tolstukhin, I.; Brooks, W. K.; Hakobyan, H.; Kuleshov, S.; Soto, O.; Toro, A.

    2013-04-01

    The barrel calorimeter of the GlueX detector in Hall D at Jefferson Lab will be instrumented with 4000 large-area (1.2x1.2 cm^2) silicon photomultipliers (SiPMs) [1]. These photon sensors have properties similar to vacuum photomultipliers, but are unaffected by high magnetic fields. In our experiment, they will operate in magnetic fields exceeding 1,. After extensive tests with a variety of sensors, we chose the S12045(X) custom SiPM arrays manufactured by Hamamatsu Corporation, also known as multi-pixel photon counters (MPPCs) [2]. All production units have been delivered and we have measured the photon detection efficiency (PDE), gain, dark rate, cross talk and after pulsing at three different temperatures (5, 7 and 20^oC). We will present a summary of these measurements and the plan for use of these sensors in the GlueX experiment.[4pt] [1] F. Barbosa et al., NIM A695 (2012) 100.[0pt] [2] Y. Qiang et al., NIM A698 (2013) 234.

  10. Study of the nature of the confinement in the GlueX experiment

    SciTech Connect

    Somov, S.; Berdnikov, Vladmir; Tolstukhin, Ivan; Somov, Alexander S.

    2015-11-01

    Confinement is a fundamental property of quantum chromodynamics (QCD) associated with the unique role of the gluonic field responsible for binding quarks in hadrons. Understanding the role of gluons in the confinement of quarks is one of the most tantalizing topics in modern particle physics to be explored. The new experiment GlueX has been recently constructed at Jefferson Lab. The experiment was designed to search for hybrid mesons with exotic quantum numbers using a beam of linearly polarized photons incident on a liquid hydrogen target. The spectrum of these states and their mass splitting from normal mesons may yield information on confinement. In addition, these observations in combination with detailed chromodynamics calculations such as on the Lattice can provide important tests for our understanding of the role of gluons. The production of exotic mesons is expected to be enhanced in p interactions, where the experimental data is very limited. We present the description of the GlueX detector, beam line, and first results of the commissioning with photon beam.

  11. N-butyl Cyanoacrylate Glue Embolization of Arterial Networks to Facilitate Hepatic Arterial Skeletonization before Radioembolization

    SciTech Connect

    Samuelson, Shaun D.; Louie, John D.; Sze, Daniel Y.

    2013-06-15

    Purpose. Avoidance of nontarget microsphere deposition via hepatoenteric anastomoses is essential to the safety of yttrium-90 radioembolization (RE). The hepatic hilar arterial network may remain partially patent after coil embolization of major arteries, resulting in persistent risk. We retrospectively reviewed cases where n-butyl cyanoacrylate (n-BCA) glue embolization was used to facilitate endovascular hepatic arterial skeletonization before RE. Methods. A total of 543 RE procedures performed between June 2004 and March 2012 were reviewed, and 10 were identified where n-BCA was used to embolize hepatoenteric anastomoses. Arterial anatomy, prior coil embolization, and technical details were recorded. Outcomes were reviewed to identify subsequent complications of n-BCA embolization or nontarget RE. Results. The rate of complete technical success was 80 % and partial success 20 %, with one nontarget embolization complication resulting in a minor change in treatment plan. No evidence of gastrointestinal or biliary ischemia or infarction was identified, and no microsphere-related gastroduodenal ulcerations or other evidence of nontarget RE were seen. Median volume of n-BCA used was <0.1 ml. Conclusion. n-BCA glue embolization is useful to eliminate hepatoenteric networks that may result in nontarget RE, especially in those that persist after coil embolization of major vessels such as the gastroduodenal and right gastric arteries.

  12. Uncertainty in urban stormwater quality modelling: the influence of likelihood measure formulation in the GLUE methodology.

    PubMed

    Freni, Gabriele; Mannina, Giorgio; Viviani, Gapare

    2009-12-15

    In the last years, the attention on integrated analysis of sewer networks, wastewater treatment plants and receiving waters has been growing. However, the common lack of data in the urban water-quality field and the incomplete knowledge regarding the interpretation of the main phenomena taking part in integrated urban water systems draw attention to the necessity of evaluating the reliability of model results. Uncertainty analysis can provide useful hints and information regarding the best model approach to be used by assessing its degrees of significance and reliability. Few studies deal with uncertainty assessment in the integrated urban-drainage field. In order to fill this gap, there has been a general trend towards transferring the knowledge and the methodologies from other fields. In this respect, the Generalised Likelihood Uncertainty Evaluation (GLUE) methodology, which is widely applied in the field of hydrology, can be a possible candidate for providing a solution to the above problem. However, the methodology relies on several user-defined hypotheses in the selection of a specific formulation of the likelihood measure. This paper presents a survey aimed at evaluating the influence of the likelihood measure formulation in the assessment of uncertainty in integrated urban-drainage modelling. To accomplish this objective, a home-made integrated urban-drainage model was applied to the Savena case study (Bologna, IT). In particular, the integrated urban-drainage model uncertainty was evaluated employing different likelihood measures. The results demonstrate that the subjective selection of the likelihood measure greatly affects the GLUE uncertainty analysis.

  13. Bridging the gap between GLUE and formal statistical approaches: approximate Bayesian computation

    NASA Astrophysics Data System (ADS)

    Sadegh, M.; Vrugt, J. A.

    2013-12-01

    In recent years, a strong debate has emerged in the hydrologic literature regarding how to properly treat nontraditional error residual distributions and quantify parameter and predictive uncertainty. Particularly, there is strong disagreement whether such uncertainty framework should have its roots within a proper statistical (Bayesian) context using Markov chain Monte Carlo (MCMC) simulation techniques, or whether such a framework should be based on a quite different philosophy and implement informal likelihood functions and simplistic search methods to summarize parameter and predictive distributions. This paper is a follow-up of our previous work published in Vrugt and Sadegh (2013) and demonstrates that approximate Bayesian computation (ABC) bridges the gap between formal and informal statistical model-data fitting approaches. The ABC methodology has recently emerged in the fields of biology and population genetics and relaxes the need for an explicit likelihood function in favor of one or multiple different summary statistics that measure the distance of each model simulation to the data. This paper further studies the theoretical and numerical equivalence of formal and informal Bayesian approaches using discharge and forcing data from different watersheds in the United States, in particular generalized likelihood uncertainty estimation (GLUE). We demonstrate that the limits of acceptability approach of GLUE is a special variant of ABC if each discharge observation of the calibration data set is used as a summary diagnostic.

  14. GLUE-IT and PEDEL-AA: new programmes for analyzing protein diversity in randomized libraries.

    PubMed

    Firth, Andrew E; Patrick, Wayne M

    2008-07-01

    There are many methods for introducing random mutations into nucleic acid sequences. Previously, we described a suite of programmes for estimating the completeness and diversity of randomized DNA libraries generated by a number of these protocols. Our programmes suggested some empirical guidelines for library design; however, no information was provided regarding library diversity at the protein (rather than DNA) level. We have now updated our web server, enabling analysis of translated libraries constructed by site-saturation mutagenesis and error-prone PCR (epPCR). We introduce GLUE-Including Translation (GLUE-IT), which finds the expected amino acid completeness of libraries in which up to six codons have been independently varied (according to any user-specified randomization scheme). We provide two tools for assisting with experimental design: CodonCalculator, for assessing amino acids corresponding to given randomized codons; and AA-Calculator, for finding degenerate codons that encode user-specified sets of amino acids. We also present PEDEL-AA, which calculates amino acid statistics for libraries generated by epPCR. Input includes the parent sequence, overall mutation rate, library size, indel rates and a nucleotide mutation matrix. Output includes amino acid completeness and diversity statistics, and the number and length distribution of sequences truncated by premature termination codons. The web interfaces are available at http://guinevere.otago.ac.nz/stats.html.

  15. Systematic Prediction of Scaffold Proteins Reveals New Design Principles in Scaffold-Mediated Signal Transduction

    PubMed Central

    Hu, Jianfei; Neiswinger, Johnathan; Zhang, Jin; Zhu, Heng; Qian, Jiang

    2015-01-01

    Scaffold proteins play a crucial role in facilitating signal transduction in eukaryotes by bringing together multiple signaling components. In this study, we performed a systematic analysis of scaffold proteins in signal transduction by integrating protein-protein interaction and kinase-substrate relationship networks. We predicted 212 scaffold proteins that are involved in 605 distinct signaling pathways. The computational prediction was validated using a protein microarray-based approach. The predicted scaffold proteins showed several interesting characteristics, as we expected from the functionality of scaffold proteins. We found that the scaffold proteins are likely to interact with each other, which is consistent with previous finding that scaffold proteins tend to form homodimers and heterodimers. Interestingly, a single scaffold protein can be involved in multiple signaling pathways by interacting with other scaffold protein partners. Furthermore, we propose two possible regulatory mechanisms by which the activity of scaffold proteins is coordinated with their associated pathways through phosphorylation process. PMID:26393507

  16. Systematic Prediction of Scaffold Proteins Reveals New Design Principles in Scaffold-Mediated Signal Transduction.

    PubMed

    Hu, Jianfei; Neiswinger, Johnathan; Zhang, Jin; Zhu, Heng; Qian, Jiang

    2015-01-01

    Scaffold proteins play a crucial role in facilitating signal transduction in eukaryotes by bringing together multiple signaling components. In this study, we performed a systematic analysis of scaffold proteins in signal transduction by integrating protein-protein interaction and kinase-substrate relationship networks. We predicted 212 scaffold proteins that are involved in 605 distinct signaling pathways. The computational prediction was validated using a protein microarray-based approach. The predicted scaffold proteins showed several interesting characteristics, as we expected from the functionality of scaffold proteins. We found that the scaffold proteins are likely to interact with each other, which is consistent with previous finding that scaffold proteins tend to form homodimers and heterodimers. Interestingly, a single scaffold protein can be involved in multiple signaling pathways by interacting with other scaffold protein partners. Furthermore, we propose two possible regulatory mechanisms by which the activity of scaffold proteins is coordinated with their associated pathways through phosphorylation process.

  17. Ginsenoside Rg1 and platelet-rich fibrin enhance human breast adipose-derived stem cell function for soft tissue regeneration.

    PubMed

    Xu, Fang-Tian; Liang, Zhi-Jie; Li, Hong-Mian; Peng, Qi-Liu; Huang, Min-Hong; Li, De Quan; Liang, Yi-Dan; Chi, Gang-Yi; Li, De Hui; Yu, Bing-Chao; Huang, Ji-Rong

    2016-06-01

    Adipose-derived stem cells (ASCs) can be used to repair soft tissue defects, wounds, burns, and scars and to regenerate various damaged tissues. The cell differentiation capacity of ASCs is crucial for engineered adipose tissue regeneration in reconstructive and plastic surgery. We previously reported that ginsenoside Rg1 (G-Rg1 or Rg1) promotes proliferation and differentiation of ASCs in vitro and in vivio. Here we show that both G-Rg1 and platelet-rich fibrin (PRF) improve the proliferation, differentiation, and soft tissue regeneration capacity of human breast adipose-derived stem cells (HBASCs) on collagen type I sponge scaffolds in vitro and in vivo. Three months after transplantation, tissue wet weight, adipocyte number, intracellular lipid, microvessel density, and gene and protein expression of VEGF, HIF-1α, and PPARγ were higher in both G-Rg1- and PRF-treated HBASCs than in control grafts. More extensive new adipose tissue formation was evident after treatment with G-Rg1 or PRF. In summary, G-Rg1 and/or PRF co-administration improves the fu