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Sample records for fibrin sealant patch

  1. 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

  2. The safety of fibrin sealants.

    PubMed

    Joch, Christine

    2003-08-01

    Fibrin sealants are prepared from fibrinogen, thrombin and sometimes also factor XIII that have been purified from human plasma. Bovine aprotinin is also included in some preparations. Each of these components has the potential to carry blood-borne pathogens, albeit at a very low frequency. In order to minimize the risk of viral transmission from commercial fibrin sealants, plasma donations undergo a series of procedures that contribute to avoiding, inactivating and eliminating potential contaminants. The procedures for selection and screening of plasma donors, and the testing of donated plasma, incorporates highly sensitive molecular techniques (e.g. PCR testing) and contributes significantly to reducing the theoretical possibility of viral transmission. The starting material for bovine aprotinin is also carefully selected, and the manufacturing process rigorously assessed, to minimize the putative risk of transmission of bovine spongiform encephalopathies. The manufacturing process for commercial fibrin sealants comprises a range of procedures, including heat treatment (e.g. pasteurization, dry or vapor heating), filtration, solvent/detergent treatment, precipitation, pH treatment and chromatography. Some steps are an inherent part of the purification process and others (e.g. pasteurization, nanofiltration) are deliberately introduced to inactivate/eliminate potential pathogens. Current manufacturing processes provide a very high degree of safety for fibrin sealants. In 20 years of worldwide use, there have been no known cases of hepatitis or HIV transmission associated with the use of commercial fibrin sealants.

  3. 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

  4. A multicentre, prospective, randomized, controlled trial comparing EVARREST™ fibrin sealant patch to standard of care in controlling bleeding following elective hepatectomy: anatomic versus non-anatomic resection

    PubMed Central

    Koea, Jonathan B.; Batiller, Jonathan; Aguirre, Nicolas; Shen, Jessica; Kocharian, Richard; Bochicchio, Grant; Garden, O. James

    2016-01-01

    Background This multicentre, randomized clinical trial assessed the safety and effectiveness of the EVARREST™ Fibrin Sealant Patch (FP) in treating parenchymal bleeding following anatomic and non-anatomic liver resections. Methods One hundred and two patients were stratified according to the type of hepatic resection (anatomic/non-anatomic), and randomized (1:1) after identification of an appropriate bleeding site, to FP vs Standard of Care (SoC, manual compression ± topical haemostat). The primary endpoint was haemostasis at 4 min from bleeding site identification with no re-bleeding requiring re-treatment. Results The FP was superior in achieving haemostasis at 4 min (96%, 48/50) to SoC (46%, 24/52; p < 0.001). Stratification for resection type showed treatment differences for primary endpoint for anatomic (24/25 FP vs 13/23 SoC; p = 0.001) and non-anatomic liver resections (24/25FP vs 11/29 SoC; p < 0.001). Adverse events related to the study procedure were reported in 40/50 patients (80%) in the FP group and 43/52 patients (83%) in the SoC group. One (2%) adverse event (infected intra-abdominal fluid collection) was possibly related to study treatment. Conclusion This clinical trial confirms that the FP is safe and highly effective in controlling parenchymal bleeding following hepatectomy regardless of the type of resection. ClinicalTrials.gov NCT01993888. PMID:27017161

  5. The role of sutures and fibrin sealant in wound healing.

    PubMed

    Spotnitz, W D; Falstrom, J K; Rodeheaver, G T

    1997-06-01

    Sutures and fibrin sealant are important surgical aids for facilitating wound closure and creating an optimal setting for wound healing. Most commonly, sutures are used to close wounds because suture material provides the mechanical support necessary to sustain closure. A wide variety of suturing material is available, and the surgeon can choose among sutures with a range of attributes to find the one best suited to his or her needs. Considerations when choosing an appropriate suture for wound closure and healing include strength of suture, holding power of tissue, absorbability, risk of infection, and inflammatory reaction associated with the suture material. Other factors to be considered include type of incision, suturing technique, and appearance of wound site. Fibrin sealant, in contrast, is a biologic tissue adhesive that can function as a useful adjunct to sutures. Fibrin sealant can be used in conjunction with sutures or tape to promote optimal wound integrity, or it can be used independently to seal wound sites where sutures cannot control bleeding or would aggravate bleeding. This adhesive can effectively seal tissue planes and eliminate potential spaces. Fibrin sealant has been used clinically in many surgical applications, although an FDA-approved commercially available product does not yet exist in the United States. Clinically, fibrin sealant has resulted in a low rate of infection and has promoted healing. Further study is needed to determine the best fibrin sealant mixtures both to achieve hemostasis and to encourage healing. It may even be desirable to use different sealant formulations for particular clinical situations.

  6. 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

  7. Hemostasis During Urologic Surgery: Fibrin Sealant Compared With Absorbable Hemostat

    PubMed Central

    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

  8. Venous gas embolism caused by fibrin sealant application to the prostate during greenlight laser photoselective vaporization.

    PubMed

    Lee, Alexander; Vazquez, Rafael

    2015-04-15

    Venous gas embolism is a complication of fibrin sealant application and is a well-described event during various modes of prostate resection. We describe the case of a nitrogen venous gas embolism during Greenlight laser photovaporization of the prostate during the application of fibrin sealant to the operative site for hemostasis. Fibrin sealant application by a compressed gas applicator is a cause of venous air embolism, and this case highlights the need to keep venous gas embolism in mind when compressed gas applicators are used.

  9. Comparison of the thrombogenicity of internationally available fibrin sealants in an established microsurgical model.

    PubMed

    Frost-Arner, L; Spotnitz, W D; Rodeheaver, G T; Drake, D B

    2001-11-01

    Previous studies comparing the thrombotic complications of cryoprecipitated fibrin sealant containing bovine thrombin on microvascular venous anastomoses in a rat epigastric free flap model revealed deleterious outcomes regarding flap survival with higher concentrations of topical bovine thrombin. This study was designed to compare three internationally available fibrin sealants, one experimental fibrin monomer sealant that does not require thrombin, and human thrombin alone as to their effects on the survival of an established rat epigastric free flap model. Ninety Sprague-Dawley rats (400 to 600 g) were prepared for abdominal surgery, and an epigastric-based skin flap was raised. The single vein draining the flap was clamped, divided, and reconnected using standard microvascular suturing techniques. Before release of the clamps, the chosen additive was applied precisely to the anastomosis. Additional material was then added to the raw surface of the flap. The animals were divided into seven treatment groups, each receiving 1 ml of commercial or investigational fibrin sealant or human thrombin alone: one control group receiving no additive treatment, four fibrin sealant groups receiving treatment with commercial or investigational fibrin sealant preparations, and two groups receiving different concentrations (500 IU/ml and 1000 IU/ml) of human thrombin applied to the anastomoses and the surrounding tissue. Flap survival was assessed at 7 days postoperatively. This study supports the contention that microvascular free flap survival based on microvascular venous anastomotic patency was adversely effected by high concentrations of thrombin. Lower concentrations (500 IU/ml and less) of thrombin did not seem to affect flap survival. One test product was composed of a fibrin monomer sealant, which obviates the need for the thrombin additive. This group's survival rate was not statistically different from that of the control group. Thus, for microvascular anastomoses

  10. 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

  11. Effect of intracameral injection of fibrin tissue sealant on the rabbit anterior segment

    PubMed Central

    Chew, Annabel C.Y.; Tan, Donald T.H.; Poh, Rebekah; HM, Htoon; Beuerman, Roger W.

    2010-01-01

    Purpose To investigate the effect of intracameral injection of fibrin tissue sealant on the anterior segment structures in a rabbit model. Methods One eye of 10 rabbits received an intracameral injection of fibrin tissue sealant with a thrombin concentration of 500 IU (TISSEEL), and the fellow eye received an intracameral injection of balanced salt solution as a control. The rabbits were followed up with serial slit-lamp examinations, photography, high resolution anterior segment optical coherence tomography scans with pachymetry measurement, and intraocular pressure (IOP) monitoring until complete dissolution of the fibrin sealant. Corneal endothelial cell viability was evaluated using live/dead cell assays. Apoptosis of the cornea and trabecular meshwork were evaluated using TUNEL assays. Ultra-structural examinations of the cornea and trabecular meshwork were performed using electron microscopy. Histology of the trabecular meshwork and iris were analyzed using light microscopy. Results The quantity of the intracameral fibrin sealant was shown to be significantly correlated with increased IOP and pachymetry post-operatively. Complete dissolution of the fibrin sealant occurred between 15 and 30 days. Live/dead cell assays showed no decrease in viability of the corneal endothelium, and TUNEL assays showed no increase in apoptosis of the corneal epithelium, stroma, endothelium, or trabecular meshwork in the eyes with the fibrin sealant. Light and electron microscopy of the anterior segment structures were unremarkable. Conclusion The intracameral use of fibrin glue was associated with a transient increase in IOP and pachymetry. However, there was no evidence of toxicity or structural damage to the corneal endothelium, trabecular meshwork, or iris. PMID:20596250

  12. Endoscopic fibrin sealant closure of duodenal perforation after endoscopic retrograde cholangiopancreatography.

    PubMed

    Yang, Hsin-Yeh; Chen, Jui-Hao

    2015-12-07

    Traditionally, perivaterian duodenal perforation can be managed conservatively or surgically. If a large volume of leakage results in fluid collection in the retroperitoneum, surgery may be necessary. Our case met the surgical indication for perivaterian duodenal perforation after endoscopic retrograde cholangiopancreatography (ERCP) with sphincterotomy and endoscopic papillary balloon dilatation. The patient developed a retroperitoneal abscess after the procedures, and a perivaterian perforation was suggested on computed tomography (CT). CT-guided abscess drainage was performed immediately. We unsuccessfully attempted to close the perforation with hemoclips initially. Subsequently, we used fibrin sealant (Tisseel) injection to occlude the perforation. Fibrin sealant injections have been previously used during endoscopy for wound closure and fistula repair. Based on our report, fibrin sealant injection can be considered as an alternative method for the treatment of ERCP-related type II perforations.

  13. Application of Fibrin Glue Sealant After Hepatectomy Does Not Seem Justified

    PubMed Central

    Figueras, Juan; Llado, Laura; Miro, Mónica; Ramos, Emilio; Torras, Jaume; Fabregat, Juan; Serrano, Teresa

    2007-01-01

    Objective: To evaluate the efficacy, amount of hemorrhage, biliary leakage, complications, and postoperative evolution after fibrin glue sealant application in patients undergoing liver resection. Summary Background Data: Fibrin sealants have become popular as a means of improving perioperative hemostasis and reducing biliary leakage after liver surgery. However, trials regarding its use in liver surgery remain limited and of poor methodologic quality. Patients and Methods: A total of 300 patients undergoing hepatic resection were randomly assigned to fibrin glue application or control groups. Characteristics and debit of drainage and postoperative complications were evaluated. The amount of blood loss, measurements of hematologic parameters liver test, and postoperative evolution (particularly involving biliary fistula and morbidity) was also recorded. Results: Postoperatively, no differences were observed in the amount of transfusion (0.15 ± 0.66 vs. 0.17 ± 0.63 PRCU; P = 0.7234) or in the patients that required transfusion (18% vs. 12%; P = 0.2), respectively, for the fibrin glue or control group. There were no differences in overall drainage volumes (1180 ± 2528 vs. 960 ± 1253 mL) or in days of postoperative drainage (7.9 ± 5 vs. 7.1 ± 4.7). Incidence of biliary fistula was similar in the fibrin glue and control groups, (10% vs. 11%). There were no differences regarding postoperative morbidity between groups (23% vs. 23%; P = 1). Conclusions: Application of fibrin sealant in the raw surface of the liver does not seem justified. Blood loss, transfusion, incidence of biliary fistula, and outcome are comparable to patients without fibrin glue. Therefore, discontinuation of routine use of fibrin sealant would result in significant cost saving. PMID:17414601

  14. 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

  15. High-Pressure Fibrin Sealant Foam: An Effective Hemostatic Agent for Treating Severe Parenchymal Hemorrhage

    DTIC Science & Technology

    2008-01-01

    least 7 days and carefully checked for any preexisting disease before undergoing surgical procedures. The daily food was withdrawn from the surgical...2003;237:871; discussion 876. 31. Jakob H, Campbell CD, Qiu ZK , et al. Use of fibrin sealant for reinforcing arterial anastomoses. J Vasc Surg 1984;1:171

  16. 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

  17. Use of autologous fibrin sealants to treat ganglion cysts: a report of two cases.

    PubMed

    Nakama, Kenjiro; Gotoh, Masafumi; Mitsui, Yasuhiro; Shirachi, Isao; Higuchi, Fujio; Nagata, Kensei

    2010-04-01

    Two patients underwent arthroscopy-guided injections of autologous fibrin sealants to treat ganglion cysts causing suprascapular nerve palsies. After at least 2 years of follow-up, both patients had no suprascapular nerve symptoms and their external rotation strength had returned to normal. Magnetic resonance imaging revealed no evidence of ganglion cyst recurrence.

  18. Treatment of post-prostatectomy rectourethral fistula with fibrin sealant (Quixil™) injection: a novel application.

    PubMed

    Verriello, V; Altomare, M; Masiello, G; Curatolo, C; Balacco, G; Altomare, D F

    2010-12-01

    Rectourethral fistulas in adults is a rare but potentially devastating postoperative condition requiring complex and demanding surgery. Fibrin glue treatment has been used with some success in anal and rectovaginal fistulas, and in the case we present here this indication has been extended to a postoperative rectourethral fistula following radical prostatectomy. For the first time, to our knowledge, a fibrin sealant (Quixil) was injected into the fistula tract, and a rectal mucosal flap was used to close the internal opening. The fistula healed in few weeks, and the patient is symptom free after 1 year of follow-up.

  19. MBCP biphasic calcium phosphate granules and tissucol fibrin sealant in rabbit femoral defects: the effect of fibrin on bone ingrowth.

    PubMed

    Le Guehennec, Laurent; Goyenvalle, Eric; Aguado, Eric; Pilet, Paul; Bagot D'Arc, Maurice; Bilban, Melitta; Spaethe, Reiner; Daculsi, Guy

    2005-01-01

    An ageing population implies an increase in bone and dental diseases, which are in turn a source of numerous handicaps. These pathologies are an expensive burden for the European health system. As no specific bioactive materials are efficient enough to cope with this burden, we have to develop an injectable, mouldable, self-hardening bone substitute to support bone tissue reconstruction and augmentation. New, highly bioactive and suitable biomaterials have been developed to replace bone grafts in orthopedic revision and maxillofacial surgery for bone augmentation. These mouldable, self-hardening materials are based on the association of MBCP Biphasic Calcium Phosphate Granules and Tissucol Fibrin Sealant. The in vivo evaluation of ingrowth in relation to the composite was made in an experiment on rabbits. The results indicate that in the presence of fibrin sealant, newly-formed bone developed at a small distance from the surface of the calcium phosphate ceramic. Two different bone apposition processes were identified. Without the fibrin component (MBCP group), bone rested directly on the surface of the granules. This observation is commonly described as osteoconduction in calcium phosphate materials. On the contrary, the presence of the fibrinogen component seemed to modify this standard osteoconduction phenomenon: the newly-formed bone essentially grew at a distance from the surface of the granules, on the fibrillar network, and could be considered as an inductive phenomenon for osteogenic cell differentiation from mesenchymal stem cells.

  20. Internal Iliac Artery Aneurysm Embolization with Fibrin Sealant: A Simple and Effective Solution

    SciTech Connect

    Brountzos, Elias N.; Malagari, Katerina; Papathanasiou, Mathildi A.; Gougoulakis, Alexandros; Kelekis, Dimitrios A.

    2003-02-15

    Endovascular treatment of internal iliac artery (IIA) aneurysms is an attractive alternative to surgical management, because the former is associated with less morbidity and mortality.Embolization with coils or exclusion of the IIA orifice with stent -grafts are the preferred techniques. Although uncommon, technical failures occur with reported aneurysm rupture. Two patients with IIA aneurysms are reported here, where we describe successful occlusion of their IIA aneurysms with the use of fibrin sealant, after initial failure of coil embolization.

  1. Laparoscopic Repair of Inguinal Hernia Using Surgisis Mesh and Fibrin Sealant

    PubMed Central

    2006-01-01

    Objective: We tested the hypothesis that laparoscopic inguinal herniorrhaphy using Surgisis mesh secured with fibrin sealant is an effective long-term treatment for repair of inguinal hernia. This case series involved 38 adult patients with 51 inguinal hernias treated in a primary care center. Methods: Between December 2002 and May 2005, 38 patients with 45 primary and 6 recurrent inguinal hernias were treated with laparoscopic repair by the total extra-peritoneal mesh placement (TEP) technique using Surgisis mesh secured into place with fibrin sealant. Postoperative complications, incidence of pain, and recurrence were recorded, as evaluated at 2 weeks, 6 weeks, 1 year, and with a follow-up questionnaire and telephone interview conducted in May and June 2005. Results: The operations were successfully performed on all patients with no complications or revisions to an open procedure. Average follow-up was 13 months (range, 1 to 30). One hernia recurred (second recurrence of unilateral direct hernia), indicating a 2% recurrence rate. Conclusions: Laparoscopic repair of inguinal hernia using Surgisis mesh secured with fibrin sealant can be effectively used to treat primary, recurrent, direct, indirect, and bilateral inguinal hernias in adults without complications and minimal recurrence within 1-year of follow-up. PMID:17575758

  2. Reduction of the closure time of postoperative enterocutaneous fistulas with fibrin sealant

    PubMed Central

    Avalos-González, Jorge; Portilla-deBuen, Eliseo; Leal-Cortés, Caridad Aurea; Orozco-Mosqueda, Abel; del Carmen Estrada-Aguilar, María; Velázquez-Ramírez, Gabriela Abigail; Ambriz-González, Gabriela; Fuentes-Orozco, Clotilde; Guzmán-Gurrola, Aldo Emmerson; González-Ojeda, Alejandro

    2010-01-01

    AIM: To assess whether the use of fibrin sealant shortens the closure time of postoperative enterocutaneous fistulas (ECFs). METHODS: The prospective case-control study included 70 patients with postoperative ECFs with an output of < 500 mL/d, a fistulous tract of > 2 cm and without any local complication. They were divided into study (n = 23) and control groups (n = 47). Esophageal, gastric and colocutaneous fistulas were monitored under endoscopic visualization, which also allowed fibrin glue application directly through the external hole. Outcome variables included closure time, time to resume oral feeding and morbidity related to nutritional support. RESULTS: There were no differences in mean age, fistula output, and follow-up. Closure-time for all patients of the study group was 12.5 ± 14.2 d and 32.5 ± 17.9 d for the control group (P < 0.001), and morbidity related to nutritional support was 8.6% and 42.5%, respectively (P < 0.01). In patients with colonic fistulas, complete closure occurred 23.5 ± 19.5 d after the first application of fibrin glue, and spontaneous closure was observed after 36.2 ± 22.8 d in the control group (P = 0.36). Recurrences were observed in 2 patients because of residual disease. One patient of each group died during follow-up as a consequence of septic complications related to parenteral nutrition. CONCLUSION: Closure time was significantly reduced with the use of fibrin sealant, and oral feeding was resumed faster. We suggest the use of fibrin sealant for the management of stable enterocutaneous fistulas. PMID:20533600

  3. Anaphylactic reaction after systemic application of aprotinin triggered by aprotinin-containing fibrin sealant.

    PubMed

    Kober, Benjamin J; Scheule, Albertus M; Voth, Vladimir; Deschner, Norbert; Schmid, Eckhard; Ziemer, Gerhard

    2008-08-01

    We report a 67-yr-old male after multiple surgical procedures for treatment of arterial occlusive disease who suffered an anaphylactic reaction after administration of aprotinin (Trasylol) prior to urgent coronary artery bypass surgery. The patient had been treated with aprotinin-containing fibrin sealant in 2004 and in 2007, 2 wk before coronary artery bypass surgery. The postoperative serologic screening revealed positive results for qualitative aprotinin-specific IgG, highly elevated quantitative aprotinin-specific IgG and moderately elevated aprotinin-specific IgE antibodies.

  4. New techniques in the treatment of common perianal diseases: stapled hemorrhoidopexy, botulinum toxin, and fibrin sealant.

    PubMed

    Singer, Marc; Cintron, Jose

    2006-08-01

    There have been several recent advances in the treatment of common perianal diseases. Stapled hemorrhoidopexy is a procedure of hemorrhoidal fixation, combining the benefits of rubber band ligation into an operative technique. The treatment of anal fissure has typically relied upon internal sphincterotomy; however, it carries a risk of incontinence. The injection of botulinum toxin represents a new form of sphincter relaxation, without division of any sphincter muscle; morbidity is minimal and results are promising. For the treatment of fistula in a fistulotomy remains the gold standard, however, it carries significant risk of incontinence. Use of fibrin sealant to treat fistulae has been met with variable success. It offers sealing of the tract, and then provides scaffolding for native tissue ingrowth.

  5. 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

  6. Characterization of mechanics and cytocompatibility of fibrin-genipin annulus fibrosus sealant with the addition of cell adhesion molecules.

    PubMed

    Guterl, Clare C; Torre, Olivia M; Purmessur, Devina; Dave, Khyati; Likhitpanichkul, Morakot; Hecht, Andrew C; Nicoll, Steven B; Iatridis, James C

    2014-09-01

    There is an unmet clinical need for a biomaterial sealant capable of repairing small annulus fibrosus (AF) defects. Causes of these defects include painful intervertebral disc herniations, microdiscectomy procedures, morbidity associated with needle puncture injury from discography, and future nucleus replacement procedures. This study describes the enhancements of a fibrin gel through genipin crosslinking (FibGen) and the addition of the cell adhesion molecules (CAMs), fibronectin and collagen. The gel's performance as a potential AF sealant is assessed using a series of in vitro tests. FibGen gels with CAMs had equivalent adhesive strength, gene expression, cytomorphology, and cell proliferation as fibrin alone. However, FibGen gels had enhanced material behaviors that were tunable to higher shear stiffness values and approximated human annulus tissue as compared with fibrin alone, were more dimensionally stable, and had a slower in vitro degradation rate. Cytomorphology of human AF cells cultured on FibGen gels exhibited increased elongation compared with fibrin alone, and the addition of CAMs to FibGen did not significantly affect elongation. This FibGen gel offers the promise of being used as a sealant material to repair small AF defects or to be used in combination with other biomaterials as an adhesive for larger defects.

  7. Characterization of Mechanics and Cytocompatibility of Fibrin-Genipin Annulus Fibrosus Sealant with the Addition of Cell Adhesion Molecules

    PubMed Central

    Guterl, Clare C.; Torre, Olivia M.; Purmessur, Devina; Dave, Khyati; Likhitpanichkul, Morakot; Hecht, Andrew C.; Nicoll, Steven B.

    2014-01-01

    There is an unmet clinical need for a biomaterial sealant capable of repairing small annulus fibrosus (AF) defects. Causes of these defects include painful intervertebral disc herniations, microdiscectomy procedures, morbidity associated with needle puncture injury from discography, and future nucleus replacement procedures. This study describes the enhancements of a fibrin gel through genipin crosslinking (FibGen) and the addition of the cell adhesion molecules (CAMs), fibronectin and collagen. The gel's performance as a potential AF sealant is assessed using a series of in vitro tests. FibGen gels with CAMs had equivalent adhesive strength, gene expression, cytomorphology, and cell proliferation as fibrin alone. However, FibGen gels had enhanced material behaviors that were tunable to higher shear stiffness values and approximated human annulus tissue as compared with fibrin alone, were more dimensionally stable, and had a slower in vitro degradation rate. Cytomorphology of human AF cells cultured on FibGen gels exhibited increased elongation compared with fibrin alone, and the addition of CAMs to FibGen did not significantly affect elongation. This FibGen gel offers the promise of being used as a sealant material to repair small AF defects or to be used in combination with other biomaterials as an adhesive for larger defects. PMID:24684314

  8. Use of a Thrombin Fibrin Sealant in Reducing Blood Loss in Revision Hip Arthroplasty

    PubMed Central

    Ghoz, Ali; Al-Khateeb, Hesham; Rajkumar, Shanmugasundaram; Tavares, Shawn; Andrade, Antonio

    2015-01-01

    We present a retrospective evaluation assessing the use of a novel fibrin sealant, Quixil® (OMRIX Biopharmaceuticals S.A.) in reducing blood transfusions following revision total hip replacement surgery. Forty four patients underwent revision total hip replacement surgery using Quixil®, while 45 patients underwent revision total hip replacement surgery without the use of Quixil®. The duration of surgery and patient demographics were similar in both groups. Average blood loss was 1,010ml in the Quixil® group versus 1,021ml in the non-Quixil group. The use of cell saver and intra-operative blood transfusion were similar in both groups. The mean pre-operative Haemoglobin was 13.0 g/dl in the Quixil® group versus 12.4 g/dl in the non-Quixil group. The mean post-operative haemoglobin was 10.2 g/dl and 9.1 g/dl in the Quixil® and non-Quixil groups respectively. There was no difference in the blood transfused post-operatively between the two groups. Total units of blood transfused in Quixil® versus non-Quixil group were 60 verus 86. Total units of intra-operative blood transfused in Quixil® versus non-Quixil group were 16 versus 23. The use of fibrin tissue adhesive in revision total hip arthroplasty seems to be an effective and reliable means to reduce blood-transfusion requirements and prevent post-operative decreases in hemoglobin. PMID:27468998

  9. Fibrin sealants from fresh or fresh/frozen plasma as scaffolds for in vitro articular cartilage regeneration.

    PubMed

    Dare, Emma V; Griffith, May; Poitras, Philippe; Wang, Tao; Dervin, Geoffrey F; Giulivi, Antonio; Hincke, Maxwell T

    2009-08-01

    Our objective was to evaluate human CryoSeal fibrin glue derived from single units of plasma as scaffolds for articular cartilage tissue engineering. Human articular chondrocytes were encapsulated into genipin cross-linked fibrin glue derived from individual units of fresh or frozen plasma using the CryoSeal fibrin sealant (FS) system. The constructs were cultured for up to 7 weeks in vitro under low (5%) or normal (21%) oxygen. Chondrocyte viability was >90% within the fibrin gels. Hypoxia induced significant increases in collagen II and Sox9 gene expression and a significant decrease in collagen I. A significant increase in collagen II was detected in fresh plasma-derived cultures, while only collagen I was significantly increased in frozen plasma cultures. Significant increases in total glycosaminoglycan and collagen were detected in the extracellular matrix secreted by the encapsulated chondrocytes. A significant increase in compression modulus was only observed for fresh plasma-derived gels, which is likely explained by a greater amount of collagen type I detected after 7 weeks in frozen compared to fresh plasma gels. Our results indicate that CryoSeal fibrin glue derived from fresh plasma is suitable as a tissue engineering scaffold for human articular chondrocytes, and therefore should be evaluated for autologous articular cartilage regeneration.

  10. The use of fibrin sealant during non-emergency surgery: a systematic review of evidence of benefits and harms.

    PubMed Central

    Edwards, Steven J; Crawford, Fay; van Velthoven, Michelle Helena; Berardi, Andrea; Osei-Assibey, George; Bacelar, Mariana; Salih, Fatima; Wakefield, Victoria

    2016-01-01

    BACKGROUND Fibrin sealants are used in different types of surgery to prevent the accumulation of post-operative fluid (seroma) or blood (haematoma) or to arrest haemorrhage (bleeding). However, there is uncertainty around the benefits and harms of fibrin sealant use. OBJECTIVES To systematically review the evidence on the benefits and harms of fibrin sealants in non-emergency surgery in adults. DATA SOURCES Electronic databases [MEDLINE, EMBASE and The Cochrane Library (including the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects, the Health Technology Assessment database and the Cochrane Central Register of Controlled Trials)] were searched from inception to May 2015. The websites of regulatory bodies (the Medicines and Healthcare products Regulatory Agency, the European Medicines Agency and the Food and Drug Administration) were also searched to identify evidence of harms. REVIEW METHODS This review included randomised controlled trials (RCTs) and observational studies using any type of fibrin sealant compared with standard care in non-emergency surgery in adults. The primary outcome was risk of developing seroma and haematoma. Only RCTs were used to inform clinical effectiveness and both RCTs and observational studies were used for the assessment of harms related to the use of fibrin sealant. Two reviewers independently screened all titles and abstracts to identify potentially relevant studies. Data extraction was undertaken by one reviewer and validated by a second. The quality of included studies was assessed independently by two reviewers using the Cochrane Collaboration risk-of-bias tool for RCTs and the Centre for Reviews and Dissemination guidance for adverse events for observational studies. A fixed-effects model was used for meta-analysis. RESULTS We included 186 RCTs and eight observational studies across 14 surgical specialties and five reports from the regulatory bodies. Most RCTs were judged to be at an

  11. Application of fibrin sealant at the urethrovesical anastomosis in robotic assisted radical prostatectomy: does it enable earlier Foley catheter and Jackson-Pratt drain removal?

    PubMed

    Flury, Sarah C; Starnes, Danielle N; Steers, William D

    2008-01-01

    Leakage at the urethrovesical anastomosis in the post-operative period can result in morbidity including ileus. We examined the effectiveness of using a fibrin sealant at the anastomosis to limit urine leakage thereby facilitating earlier Jackson-Pratt drain and Foley catheter removal following robotic assisted laparoscopic prostatectomy (RALRP). Forty consecutive patients underwent RALRP by one surgeon at our institution. The first 20 patients underwent standard operation and served as the control group. The subsequent 20 patients underwent the same operation with addition of fibrin sealant following a running absorbable sutured urethrovesical anastomosis. The two groups were compared for age (60.5 vs. 58.2 years), pre-operative PSA (5.23 vs. 4.71), Gleason score (6.3 vs. 6.5), stage at resection, and prostate size at resection (51.7 vs. 47.7 g). Wilcoxon rank sum test determined no statistically significant differences in the groups. Patients in the fibrin sealant group had 1.3 versus 2.1 days with a Jackson-Pratt drain, 9.75 versus 12.1 days with a catheter, and an average of 38.6 versus 63.2 cc of drainage per shift. Catheters were removed when a cystogram demonstrated no extravasation of contrast. Two patients in the control group and no patients in the fibrin sealant group had large-volume leakage and ileus post-operatively. In patients undergoing RALRP, application of fibrin sealant at the urethrovesical anastomosis appears to facilitate sealing, thereby allowing earlier removal of the JP drain, by 0.8 days, and the Foley catheter, by 2.35 days, than in controls. No patients in the fibrin sealant group suffered post-operative ileus. This adjunct may be especially useful early in the learning process to reduce morbidity.

  12. Influence of calcium chloride and aprotinin in the in vivo biological performance of a composite combining biphasic calcium phosphate granules and fibrin sealant.

    PubMed

    Le Guehennec, Laurent; Goyenvalle, Eric; Aguado, Eric; Pilet, Paul; Spaethe, Reiner; Daculsi, Guy

    2007-08-01

    Highly bioactive biomaterials have been developed to replace bone grafts in orthopedic revision and maxillofacial surgery for bone augmentation. A mouldable, self-hardening material can be obtained by combining TricOs Biphasic Calcium Phosphate Granules and Tissucol Fibrin Sealant. Two components, calcium chloride and antifibrinolytic agents (aprotinin), are essential for the stability of the fibrin clot. The ingrowth of cells in composites combining sealants without calcium chloride or with a low concentration of aprotinin was evaluated in vivo in an experiment on rabbits. Bone colonization was compared using TricOs alone or with the composite made from TricOs and the standard fibrin sealant. Without the addition of calcium chloride, the calcium ions released by the ceramic component interacted with the components of the sealant too late to stabilize the clot. With a low concentration of aprotinin, the degradation of the clot occurred more quickly, leading to the absence of a scaffold on which the bone cells could colonize the composite. Our results indicate that a stable fibrin scaffold is crucial for bone colonization. The low calcium chloride and low aprotinin groups have shown lower bone growth. Further studies will be necessary to determine the minimal amount of antifibrinolytic agent (aprotinin) necessary to allow the same level of osteogenic activity as the TricOs-fibrin glue composite.

  13. Effects of low-level laser therapy on autogenous bone graft stabilized with a new heterologous fibrin sealant.

    PubMed

    de Oliveira Gonçalves, Jéssica Barbosa; Buchaim, Daniela Vieira; de Souza Bueno, Cleuber Rodrigo; Pomini, Karina Torres; Barraviera, Benedito; Júnior, Rui Seabra Ferreira; Andreo, Jesus Carlos; de Castro Rodrigues, Antonio; Cestari, Tania Mary; Buchaim, Rogério Leone

    2016-09-01

    Autogenous bone grafts are used to repair bone defects, and the stabilization is needed for bone regeneration. Laser photobiomodulation is a modality of treatment in clinical practice for tissue regeneration, and it has therapeutic effects as an anti-inflammatory, analgesic and modulating cellular activity. The aim of the present study was to evaluate the effects of low-level laser therapy (LLLT) on an autogenous bone graft integration process stabilized with a new heterologous fibrin sealant. Forty rats were divided into two groups: Autogenous Fibrin Graft (AFG, n=20), in which a 5mm dome osteotomy was conducted in the right parietal bone and the graft was adhered to the left side using fibrin sealant; and Autogenous Fibrin Graft Laser (AFGL, n=20), which was subjected to the same procedures as AFG with the addition of LLLT. The treatment was performed immediately following surgery and then three times a week until euthanasia, using an 830nm laser (30mW, 6J/cm(2), 0.116cm(2), 258.6mW/cm(2), 2.9J). Five animals from each group were euthanized at 10, 20, 30 and 40days postoperative, and the samples were submitted to histomorphological and histomorphometric analysis. Partial bone regeneration occurred, with new bone tissue integrating the graft to the recipient bed and small areas of connective tissue. Comparative analysis of the groups at the same intervals revealed minor interfaces in group AFGL, with statistically significant differences (p<0.05) at all of the analyzed intervals (10days p=0.0087, 20days p=0.0012, 30days p<0.0001, 40days p=0.0142). In conclusion, low-level laser therapy stimulated bone regeneration and accelerated the process of integration of autogenous bone grafts.

  14. Treatment of 213 patients with Symptomatic Tarlov Cysts by CT-guided Percutaneous Injection of Fibrin Sealant

    PubMed Central

    Murphy, Kieran; Oaklander, Anne Louise; Elias, Gavin; Kathuria, Sudhir; Long, Donlin M.

    2015-01-01

    Purpose The purpose of this study was to analyze the safety and efficacy of intervention in patients with symptomatic Tarlov cysts by percutaneous, CT-guided two-needle cyst aspiration and fibrin sealant injection. Materials and Methods This study was designed to assess outcomes in patients who underwent CT-guided aspiration and injection of one or more sacral Tarlov cysts at Johns Hopkins Hospital between the years of 2003 and 2013. In all, 289 cysts were treated in 213 consecutive patients. All of these patients were followed for at least six months; 90% were followed for one year and 83% were followed for three to six years. The aspiration-injection procedure employed two needles and was carried out with local anesthesia and intravenous analgesia. In the fibrin injection stage of the procedure, a commercially available fibrin sealant was injected into the cyst through the deep needle (Tisseel VH; Baxter Healthcare, Westlake Village, California). Results One year post-procedure, excellent results had been obtained in 104 patients (54.2% of patients followed) and good or satisfactory results had been obtained in 53 patients (27.6%). Thus, 157 patients (81.8%) in all were initially satisfied with the outcome of treatment. At three to six years post-procedure, 74.0% of patients followed were satisfied with treatment. There were no significant complications. Conclusions The aspiration-injection technique described herein constitutes a safe and efficacious treatment option that holds promise for relieving cyst-related symptoms in many patients with very small risk. PMID:26405086

  15. Fibrin sealant for closure of mucosal penetration at the cardia during peroral endoscopic myotomy: A retrospective study at a single center

    PubMed Central

    Zhang, Wen-Gang; Linghu, En-Qiang; Li, Hui-Kai

    2017-01-01

    AIM To assess the efficacy and safety of fibrin sealant for closure of mucosal penetration at the cardia during peroral endoscopic myotomy (POEM). METHODS Twenty-four patients who underwent POEM and experienced mucosal injury of the cardia during the procedure were retrospectively identified. Of the 24 patients, 21 had mucosal penetration and 3 had only slight mucosal damage without penetration. The 21 patients with mucosal penetration received fibrin sealant for closure at the site of penetration. Penetration-related characteristics, treatment, and recovery were reviewed for all 21 patients to assess the efficacy and safety of fibrin sealant for closure of mucosal penetration at the cardia. Clinical data, including general characteristics, procedure-related parameters, Eckardt scores, lower esophageal sphincter pressures (LESP), and esophagogastroduodenoscopy (EGD) results, were analyzed to determine their influence on treatment success after mucosal penetration during POEM. RESULTS All 21 patients had a solitary mucosal penetration in the cardia (12 in esophageal region of the cardia, 9 in the stomach region of the cardia, and 1 in both the esophageal and stomach regions). Twelve had a hole-like penetration and 9 had a linear penetration. For those with a hole-like penetration, the mean size was 0.14 cm2 (0.02-0.32 cm2). For those with a linear penetration, the median size was 0.37 cm (0.10-1.00 cm). Closure of the mucosal penetration using fibrin sealant was performed successfully in all 21 patients (two patients required 5 mL fibrin sealant, and the remaining 19 patients required 2.5 mL). Two patients had a nasogastric tube placed for five days after POEM; the remaining 19 patients were kept fasting for 3 d. All 21 patients were discharged after a median of 5 d (range: 5-7 d) postoperatively. During a median 42 mo (range: 9-62 mo) follow-up, all 21 patients with a mucosal penetration successfully healed without the occurrence of infection, ulcer, or esophagitis

  16. Fibrin sealant combined with fibroblasts and platelet-derived growth factor enhance wound healing in excisional wounds.

    PubMed

    Mogford, Jon E; Tawil, Bill; Jia, Shengxian; Mustoe, Thomas A

    2009-01-01

    We test the hypothesis that the fibrinogen-thrombin formulation of fibrin sealant combined with fibroblasts and PDGF-BB enhance cutaneous wound healing. Four formulations varying in fibrinogen and thrombin concentration were applied to full-thickness biopsy wounds in the rabbit ear cutaneous wound healing model with or without cultured rabbit dermal fibroblasts (RDFs; 3 x 10(5) cells/wound) embedded in the fibrinogen component. At post-wounding day 7, there was no difference in the diluted vs. non-diluted formulations for either the promotion of granulation tissue coverage of the open wounds or total granulation tissue area when tested without embedded cells. Including the RDFs, the highest degree of wound coverage by granulation tissue was observed in the combined dilution formulation (17.3 mg/mL fibrinogen, 167 U/mL thrombin; n=10 wounds) that was 167% (p<0.05) of the nondiluted FS containing cells (50 mg/mL fibrinogen, 250 U/mL thrombin; n=10 wounds). Inclusion of fibroblasts increased granulation tissue area within the wounds vs. FS alone (p<0.05) for each diluted formulation although no differences in this parameter were observed within each group (FS alone or with embedded cells). However, addition of the vulnerary growth factor PDGF-BB (3 mg; n=4) with the embedded RDFs in the combined dilution formulation increased granulation tissue area over two-fold (p<0.01) over FS alone. Additionally, the presence of the RDFs promoted incorporation of the granulation tissue with and epithelial migration over the FS suggesting an active interaction between cells delivered to the wound by FS and the host repair cells. The findings suggest the progress of cutaneous defect repair can be enhanced by ex vivo cell delivery in fibrin sealant.

  17. Fibrin patch-based insulin-like growth factor-1 gene-modified stem cell transplantation repairs ischemic myocardium

    PubMed Central

    Li, Jun; Zhu, Kai; Yang, Shan; Wang, Yulin; Guo, Changfa; Yin, Kanhua; Wang, Chunsheng

    2015-01-01

    Bone marrow mesenchymal stem cells (BMSCs), tissue-engineered cardiac patch, and therapeutic gene have all been proposed as promising therapy strategies for cardiac repair after myocardial infarction. In our study, BMSCs were modified with insulin-like growth factor-1 (IGF-1) gene, loaded into a fibrin patch, and then transplanted into a porcine model of ischemia/reperfusion (I/R) myocardium injury. The results demonstrated that IGF-1 gene overexpression could promote proliferation of endothelial cells and cardiomyocyte-like differentiation of BMSCs in vitro. Four weeks after transplantation of fibrin patch loaded with gene-modified BMSCs, IGF-1 overexpression could successfully promote angiogenesis, inhibit remodeling, increase grafted cell survival and reduce apoptosis. In conclusion, the integrated strategy, which combined fibrin patch with IGF-1 gene modified BMSCs, could promote the histological cardiac repair for a clinically relevant porcine model of I/R myocardium injury. PMID:25767192

  18. Hemostasis and other benefits of fibrin sealants/glues in spine surgery beyond cerebrospinal fluid leak repairs

    PubMed Central

    Epstein, Nancy E.

    2014-01-01

    Background: Fibrin sealants (FS)/glues (FG) are primarily utilized in spinal surgery to either strengthen repairs of elective (e.g., intradural tumors/pathology) or traumatic cerebrospinal fluid (CSF) fistulas. Here, additional roles/benefits of FS/FG in spine surgery are explored; these include increased hemostasis, reduction of scar, reduction of the risk of infection if impregnated with antibiotics, and its application to restrict diffusion and limit some of the major complications attributed to the controversial “off-label” use of bone morphogeneitc protein (rhBMP-2/INFUSE). Methods: We reviewed multiple studies, focusing not just on the utility of FS/FG in the treatment of CSF fistulas, but on its other applications. Results: FS/FG have been primarily used to supplement elective/traumatic dural closure in spinal surgery. However, FS/FG also contribute to; hemostasis, reducing intraoperative/postoperative bleeding/transfusion requirements, length of stay (LOS)/costs, reduced postoperative scar/radiculitis, and infection when impregnated with antibiotics. Nevertheless, one should seriously question whether FS/FG should be applied to prevent diffusion and limit major complications attributed to the “off-label” use of BMP/INFUSE (e.g., limit/prevent heterotopic ossification, dysphagia/respiratory decompensation, and new neurological deficits). Conclusions: FS/FG successfully supplement watertight dural closure following elective (e.g., intradural tumor) or traumatic CSF fistulas occurring during spinal surgery. Additional benefits include: intraoperative hemostasis with reduced postoperative drainage, reduced transfusion requirements, reduced LOS, cost, scar, and prophylaxis against infection (e.g., impregnated with antibiotics). However, one should seriously question whether FS/FG should be used to contain the diffusion of BMP/INFUSE and limit its complications when utilized “off-label”. PMID:25289150

  19. Prophylactic use of fibrin sealant (ARTISS(™) ) for facilitating safe transition to drain-free thyroid surgery: a single-centre case series review of 109 procedures.

    PubMed

    Heyes, Richard; Ramdoo, Krishan; Manjaly, Joseph G; Charn, Tze Choong; Tatla, Taran

    2017-02-24

    Despite a lack of evidence to support drain insertion in thyroid surgery, drain placement, to prevent rapidly expanding haematoma which occurs in around 1% of cases, remains common (1,2,3) . Throughout surgery there has been a drive towards reducing postoperative length of hospital admission. For day-case thyroidectomy to become a widely adopted clinical reality, the use of drains requires abandonment, but beyond this, the cause for surgeons' reticence to practise drain-free surgery, namely haematoma risk, needs to be addressed. This paper describes a study conducted to examine the efficacy of ARTISS(™) , a commercially available thrombin-dilute fibrin sealant, in thyroid surgery to permit safe transition to drain-free surgery. This article is protected by copyright. All rights reserved.

  20. 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

  1. Postinfarction Functional Recovery Driven by a Three-Dimensional Engineered Fibrin Patch Composed of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells

    PubMed Central

    Roura, Santiago; Soler-Botija, Carolina; Bagó, Juli R.; Llucià-Valldeperas, Aida; Férnandez, Marco A.; Gálvez-Montón, Carolina; Prat-Vidal, Cristina; Perea-Gil, Isaac; Blanco, Jerónimo

    2015-01-01

    Considerable research has been dedicated to restoring myocardial cell slippage and limiting ventricular remodeling after myocardial infarction (MI). We examined the ability of a three-dimensional (3D) engineered fibrin patch filled with human umbilical cord blood-derived mesenchymal stem cells (UCBMSCs) to induce recovery of cardiac function after MI. The UCBMSCs were modified to coexpress luciferase and fluorescent protein reporters, mixed with fibrin, and applied as an adhesive, viable construct (fibrin-cell patch) over the infarcted myocardium in mice (MI-UCBMSC group). The patch adhered well to the heart. Noninvasive bioluminescence imaging demonstrated early proliferation and differentiation of UCBMSCs within the construct in the postinfarct mice in the MI-UCBMSC group. The implanted cells also participated in the formation of new, functional microvasculature that connected the fibrin-cell patch to both the subjacent myocardial tissue and the host circulatory system. As revealed by echocardiography, the left ventricular ejection fraction and fractional shortening at sacrifice were improved in MI-UCBMSC mice and were markedly reduced in mice treated with fibrin alone and untreated postinfarction controls. In conclusion, a 3D engineered fibrin patch composed of UCBMSCs attenuated infarct-derived cardiac dysfunction when transplanted locally over a myocardial wound. Significance Ischemic heart failure (HF) is the end stage of many cardiovascular diseases, including myocardial infarction. The only definitive treatment for HF is cardiac transplant, which is hampered by limited number of heart donors and graft rejection. In recent times, cellular cardiomyoplasty has been expected to repair infarcted myocardium by implantation of different sources of stem or progenitor cells. However, low cell survival and myocardial implantation rates have motivated the emergence of novel approaches with the objective of generating graftable cell-based implants. Here, the potential

  2. Comparison of fibrin sealant and staples for attaching split-thickness autologous sheet grafts in patients with deep partial- or full-thickness burn wounds: a phase 1/2 clinical study.

    PubMed

    Gibran, Nicole; Luterman, Arnold; Herndon, David; Lozano, Daniel; Greenhalgh, David G; Grubbs, Lisa; Schofield, Neil; Hantak, Edith; Callahan, Janice D; Schiestl, Nina; Riina, Louis H

    2007-01-01

    We undertook a multicenter, randomized, controlled, phase 1/2 clinical study to investigate the safety and efficacy of a fibrin sealant containing 4 IU/ml thrombin (FS 4IU) for the attachment of autologous sheet grafts in patients with deep partial-thickness or full-thickness burn wounds. Fibrin sealant (FS 4IU) was compared with staples for adherence of sheet grafts in 40 patients. Patients had to have burn wounds measuring 40% TBSA or less with two comparable test sites measuring between 1% and 4% TBSA each. Wound beds were prepared before treatment assignment, which was randomized. Percent area of hematoma/seroma at Day 1 (P = .0138) and questionable viability at Day 5 (P = .0182) were significantly less for FS 4IU-treated sites. Median percent area of graft survival on Day 14 was 100% for both treatments (P = .3525). The percentage of completely closed sites generally was greater for FS 4IU-sites on Days 5 to 91; the maximum difference occurred at Day 28 (79.5% vs 59%; P = .0215). The safety profile of FS 4IU was excellent as indicated by the lack of any related serious adverse experiences. These findings indicate that FS 4IU is safe and effective for fixation of skin grafts, with outcomes similar to or better than staple fixation. The data suggest that FS 4IU is a promising candidate for further clinical studies focusing on skin graft adhesion and burn wound healing.

  3. Efficacy and safety of a fibrin sealant for adherence of autologous skin grafts to burn wounds: results of a phase 3 clinical study.

    PubMed

    Foster, Kevin; Greenhalgh, David; Gamelli, Richard L; Mozingo, David; Gibran, Nicole; Neumeister, Michael; Abrams, Steven Zvi; Hantak, Edith; Grubbs, Lisa; Ploder, Bettina; Schofield, Neil; Riina, Louis H

    2008-01-01

    The objective of this phase 3, multicentered, prospective, randomized, evaluator-blinded, clinical study was to compare skin graft adherence utilizing a fibrin sealant containing 4 IU/ml thrombin (FS 4IU VH S/D [FS 4IU VH S/D will be marketed under the trade name ARTISS upon licensure in the United States]) to graft adherence utilizing staples in burn patients requiring wound excision and skin grafting. FS 4IU VH S/D was compared with staples in 138 patients. Patients had burn wounds measuring < or =40% of total body surface area with two comparable test sites measuring between 1 and 4% total body surface area each. Wound closure at day 28 was assessed using test site planimetry and review of day 28 photographs by three independent blinded evaluators (primary endpoint analysis). Secondary efficacy measures included hematoma/seroma on day 1, engraftment on day 5, and wound closure on day 14. Investigator and patient-reported outcomes were also assessed. The proportion of test sites with complete wound closure at day 28 was 70.3% in FS 4IU VH S/D treated sites and 65.8% in stapled sites, as assessed by planimetry. Blinded review of day 28 photographs confirmed that the rate of complete wound closure was similar between the two treatments, although the overall assessed rates of closure were lower than those determined by planimetry: FS 4IU VH S/D (43.3%) and staples (37.0%). The lower limit of the 97.5% confidence interval of the difference between FS 4IU VH S/D and staples was -0.029, which is above the predefined noninferiority margin of -0.1. Therefore, FS 4IU VH S/D is at least as efficacious as staples at the 97.5% one-sided level for complete wound closure by day 28. Hematoma/seroma on day 1 occurred at significantly (P < .0001) fewer FS 4IU VH S/D-treated sites (29.7% [95% CI 22.2-38.1%]) compared with stapled sites (62.3% [95% CI 53.7-70.4%]). Engraftment on day 5 was deemed to be 100% in 62.3% (95% CI 53.7-70.4%) of the FS 4IU VH S/D-treated sites and 55

  4. Staple Line Coverage with a Polyglycolic Acid Patch and Fibrin Glue without Pleural Abrasion after Thoracoscopic Bullectomy for Primary Spontaneous Pneumothorax

    PubMed Central

    Hong, Ki Pyo; Kim, Do Kyun; Kang, Kyung Hoon

    2016-01-01

    Background This study was conducted to determine the efficacy of staple line coverage using a polyglycolic acid patch and fibrin glue without pleural abrasion to prevent recurrent postoperative pneumothorax. Methods A retrospective analysis was carried out of 116 operations performed between January 2011 and April 2013. During this period, staple lines were covered with a polyglycolic acid patch and fibrin glue in 58 cases (group A), while 58 cases underwent thoracoscopic bullectomy only (group B). Results The median follow-up period was 33 months (range, 22 to 55 months). The duration of chest tube drainage was shorter in group A (group A 2.7±1.2 day vs. group B 3.9±2.3 day, p=0.001). Prolonged postoperative air leakage occurred more frequently in group B than in group A (43% vs. 19%, p=0.005). The postoperative recurrence rate of pneumothorax was significantly lower in group A (8.6%) than in group B (24.1%) (p=0.043). The total cost of treatment during the follow-up period, including the cost for the treatment of postoperative recurrent pneumothorax, was not significantly different between the two groups (p=0.43). Conclusion Without pleural abrasion, staple line coverage with a medium-sized polyglycolic acid patch and fibrin glue after thoracoscopic bullectomy for primary spontaneous pneumothorax is a useful technique that can reduce the duration of postoperative pleural drainage and the postoperative recurrence rate of pneumothorax. PMID:27066431

  5. Fibrin structure and wound healing.

    PubMed

    Laurens, N; Koolwijk, P; de Maat, M P M

    2006-05-01

    Fibrinogen and fibrin play an important role in blood clotting, fibrinolysis, cellular and matrix interactions, inflammation, wound healing, angiogenesis, and neoplasia. The contribution of fibrin(ogen) to these processes largely depends not only on the characteristics of the fibrin(ogen) itself, but also on interactions between specific-binding sites on fibrin(ogen), pro-enzymes, clotting factors, enzyme inhibitors, and cell receptors. In this review, the molecular and cellular biology of fibrin(ogen) is reviewed in the context of cutaneous wound repair. The outcome of wound healing depends largely on the fibrin structure, such as the thickness of the fibers, the number of branch points, the porosity, and the permeability. The binding of fibrin(ogen) to hemostasis proteins and platelets as well as to several different cells such as endothelial cells, smooth muscle cells, fibroblasts, leukocytes, and keratinocytes is indispensable during the process of wound repair. High-molecular-weight and low-molecular-weight fibrinogen, two naturally occurring variants of fibrin, are important determinants of angiogenesis and differ in their cell growth stimulation, clotting rate, and fibrin polymerization characteristics. Fibrin sealants have been investigated as matrices to promote wound healing. These sealants may also be an ideal delivery vehicle to deliver extra cells for the treatment of chronic wounds.

  6. 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.

  7. Ocular surface sealants and adhesives.

    PubMed

    Bhatia, Subir Singh

    2006-07-01

    Tissue adhesives, both synthetic and biologic, have a long history of use in ophthalmology. Cyanoacrylate-based glues have traditionally been the most widely used glues for various purposes. They have been specially useful for treating corneal perforations and have had significantly improved long-term outcomes. More recently, fibrin-based glues have gained a major role as a suture substitute for attaching biologic tissues and as surface sealants. The literature supports expanded use of fibrin glue in this fashion. Other new agents, such as polyethyelene glycols, have been underutilized and hold promise, especially as surface protectants. Numerous other glues are being developed and show promise as ocular surface sealants and protective membranes. Advances in knowledge about tissue adhesives are leading to more effective and efficient ophthalmic care.

  8. [Experimental study on application recombinant human bone morphogenetic protein 2(rhBMP-2)/poly-lactide-co-glycolic acid (PLGA)/fibrin sealant(FS) on repair of rabbit radial bone defect].

    PubMed

    Fan, Zhongkai; Cao, Yang; Zhang, Zhe; Zhang, Mingchao; Lu, Wei; Tang, Lei; Yao, Qi; Lu, Gang

    2012-10-01

    This paper is aimed to investigate the repair of rabbit radial bone defect by the recombinant human bone morphogenetic protein 2/poly-lactideco-glycolic acid microsphere with fibrin sealant (rhBMP-2/PLGA/FS). The radial bone defect models were prepared using New Zealand white rabbits, which were randomly divided into 3 groups, experiment group which were injected with eMP-2/PLGA/FS at bone defect location, control group which were injected with FS at bone defect location, and blank control group without treatment. The ability of repairing bone defect was evaluated with X-ray radiograph. Bone mineral density in the defect regions was analysed using the level of ossification. The osteogenetic ability of repairing bone defect, the degradation of the material, the morphologic change and the bone formation were assessed by HE staining and Masson staining. The result showed that rhBMP-2/PLGA/FS had overwhelming superiority in the osteogenetic ability and quality of bone defect over the control group, and it could promote the repair of bone defect and could especially repair the radial bone defect of rabbit well. It may be a promising and efficient synthetic bone graft.

  9. Dental sealants

    MedlinePlus

    ... few quick steps. There is no drilling or scraping of the molars. Your dentist will: Clean the ... Dental sealants. Updated October 19, 2016. ADA.org Web site. www.ada.org/en/member-center/oral- ...

  10. Experimental measure of the tensile strength of biological sealant-collagen association after hepatectomy in dogs.

    PubMed

    Scotté, M; Dujardin, F; Amelot, A; Azema, P; Leblanc, I; Bouvier, P; Michot, F; Ténière, P

    1996-01-01

    Fibrin sealants are commonly used in liver surgery. The aim of this study was to test the adhesive properties of a biological sealant-collagen bonding, using an experimental model. After hepatectomy in dogs, we measured the rupture stress point of a fibrin clot on the liver cross-section. The tensile strength was 0.28 N, 5 times higher than the force of arterial pressure in a 2-mm-diameter vessel. These results indicate that the adhesion of fibrin sealants is effective to prevent hemorrhage from the liver cross-section after hepatectomy.

  11. Lendrum (-MSB) staining for fibrin identification in sealed skin grafts.

    PubMed

    Fisseler-Eckhoff, A; Müller, K M

    1994-05-01

    The significance and effect of fibrin sealant systems for woundhealing are still unknown, because of the use of insufficient, conventional staining methods for the demonstration of the fibrin components used by sealant systems. From 21 patients with extensive burns of 2nd and 3rd degree biopsies of the skin were obtained during consecutive operations to cover the defect of the skin with split-thickness skin grafting. In the present paper morphological results concerning the demonstration of fibrin components and morphological differences in woundhealing of sealed and unsealed skin grafts are presented using Lendrum (-MSB) staining. With this staining method it is possible to identify exogenous fibrin components of the sealant system and to differentiate between fresh and older fibrin components, due to colour changes depending on time.

  12. New method to prepare autologous fibrin glue on demand.

    PubMed

    Alston, Steven M; Solen, Kenneth A; Broderick, Adam H; Sukavaneshvar, Sivaprasad; Mohammad, S Fazal

    2007-04-01

    Fibrin-based sealants are commonly employed to arrest bleeding after surgery. Usually, fibrinogen obtained from pooled human plasma is used to prepare sealants, with attendant risk of blood-borne infections. Availability of autologous fibrinogen would eliminate this risk. To prepare autologous fibrin sealant, fibrinogen was precipitated from human plasma using protamine. Under optimal conditions (10-mg/mL protamine and 22 degrees C), 96 +/- 4% of clottable fibrinogen was recovered by a simple and inexpensive technique. Nearly 50% of the plasma factor XIII was also recovered with the fibrinogen. Using bovine thrombin, the fibrinogen was clotted (1) in a specially designed mold to measure tensile strength and (2) in a lap joint between 2 aortic vessel strips to measure adhesion strength. Tensile and adhesion strengths increased with increasing fibrinogen concentration, and they were increased by the addition of calcium chloride. The addition of aprotinin and -aminocaproic acid to the fibrinogen concentrate before clotting had no effect on the mechanical properties of the clots. After adding thrombin to sealant containing 15-mg/mL fibrinogen, maximum tensile strength was achieved in 1-5 min, and maximum adhesion strength was reached in 5-15 min. For the sealant with 30-60-mg/mL fibrinogen and added calcium, the tensile strength was equivalent to that of the commercial fibrin sealant Tisseel. The adhesion strength of sealant with 30-60-mg/mL fibrinogen exceeded the adhesive strength of Tisseel under identical conditions. Autologous fibrin sealant is an attractive alternative to commercial sealants. It can be readily prepared from 5-mL plasma or more and exhibits mechanical properties equivalent to those of the leading commercial sealant.

  13. 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

  14. Enhanced Sealing by Hydrophobic Modification of Alaska Pollock-Derived Gelatin-Based Surgical Sealants for the Treatment of Pulmonary Air Leaks.

    PubMed

    Mizuta, Ryo; Taguchi, Tetsushi

    2016-11-15

    Pulmonary air leaks are medical complications of thoracic surgery for which fibrin sealant is the main treatment. In this study, innovative sealants based on hydrophobically modified Alaska pollock-derived gelatin (hm-ApGltn) and a poly(ethylene)glycol-based 4-armed cross-linker (4S-PEG) have been developed and their burst strengths have been evaluated using fresh rat lung. The developed sealants show higher lung burst strength compared with the nonmodified original ApGltn (Org-ApGltn)-based sealant and a commercial fibrin sealant. The maximum burst strength of the hm-ApGltn-based sealant is 1.6-fold higher than the Org-ApGltn-based sealant (n = 5, p < 0.05), and 2.1-fold higher than the commercial fibrin sealant (n = 5, p < 0.05). Cell culture experiments show that modification of ApGltn with cholesteryl or stearoyl groups effectively enhances anchoring to the cell surface. In addition, binding constants between hm-ApGltn and extracellular matrix proteins such as fibronectin and fibrillin are increased. Therefore, the new hm-ApGltn/4S-PEG-based sealant has the potential for applications in thoracic surgery.

  15. Salmon fibrin glue in rats: antibody studies.

    PubMed

    Laidmäe, Ivo; Belozjorova, Jevgenia; Sawyer, Evelyn S; Janmey, Paul A; Uibo, Raivo

    2012-01-01

    Fibrin sealants and topical thrombin preparations are often used for haemostatic and sealing applications in clinical practice. Some of these preparations contain coagulation factors from bovine sources. To minimize the risk of infection and immunogenicity connected with mammalian blood products, proteins derived from the plasma of farmed Atlantic salmon have been considered as an alternative to these mammalian sources. The purpose of this study is to characterize the immunogenicity of salmon fibrin glue in an animal model focusing on crossreactivity of IgG antibodies to host endogenous counterparts. After two immunizations with salmon fibrin glue, rats developed antibodies of IgG and IgM type to both fibrin glue components. Weak crossreactivity to endogenous fibrinogen and thrombin was seen in a subset of rats after the second application of salmon proteins. Coagulation tests showed that salmon fibrin application has no effect on coagulation profiles in mammalian hosts, consistent with previous reports that found no evidence of significant crossreactivity with host proteins. These studies support the potential suitability of salmon fibrin glue for the development of preparations with clinical impact. Before human use can be considered, however, additional data about safety of this preparation in other animal models, including large animal studies, should be obtained.

  16. Advanced supersonic technology fuel tank sealants

    NASA Technical Reports Server (NTRS)

    Rosser, R. W.; Parker, J. A.

    1976-01-01

    Status of the fuel tank simulation and YF-12A flight tests utilizing a fluorosilicone sealant is described. New elastomer sealant development is detailed, and comparisons of high and low temperature characteristics are made to baseline fluorosilicone sealants.

  17. 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

  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.

  19. Engineering fibrin polymers through engagement of alternative polymerization mechanisms.

    PubMed

    Stabenfeldt, Sarah E; Gourley, Merek; Krishnan, Laxminarayanan; Hoying, James B; Barker, Thomas H

    2012-01-01

    Fibrin is an attractive material for regenerative medicine applications. It not only forms a polymer but also contains cryptic matrikines that are released upon its activation/degradation and enhance the regenerative process. Despite this advantageous biology associated with fibrin, commercially available systems (e.g. TISSEEL) display limited regenerative capacity. This limitation is in part due to formulations that are optimized for tissue sealant applications and result in dense fibrous networks that limit cell infiltration. Recent evidence suggests that polymerization knob 'B' engagement of polymerization hole 'b' activates an alternative polymerization mechanism in fibrin, which may result in altered single fiber mechanical properties. We hypothesized that augmenting fibrin polymerization through the addition of PEGylated knob peptides with specificity to hole 'b' (AHRPYAAC-PEG) would result in distinct fibrin polymer architectures with grossly different physical properties. Polymerization dynamics, polymer architecture, diffusivity, viscoelasticity, and degradation dynamics were analyzed. Results indicate that specific engagement of hole 'b' with PEGylated knob 'B' conjugates during polymerization significantly enhances the porosity of and subsequent diffusivity through fibrin polymers. Paradoxically, these polymers also display increased viscoelastic properties and decreased susceptibility to degradation. As a result, fibrin polymer strength was significantly augmented without any adverse effects on angiogenesis within the modified polymers.

  20. 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.

  1. New Joint Sealants. Criteria, Design and Materials.

    ERIC Educational Resources Information Center

    Building Research Inst., Inc., Washington, DC.

    Contents include--(1) sealing concrete joints, (2) sealing glass and metal joints, (3) metal and glass joint sealants from a fabricator's viewpoint, (4) a theory of adhesion for joint sealants, (5) geometry of simple joint seals under strain, (6) joint sealant specifications from a manufacturer's viewpoint, (7) joint sealant requirements from an…

  2. Fibrin sealing versus stapling of hernia meshes in an onlay model in the rat.

    PubMed

    Petter-Puchner, Alexander H; Fortelny, R; Mittermayr, R; Ohlinger, W; Redl, H

    2005-12-01

    Incisional and inguinal hernia repair are among the most common procedures of general surgery. Mesh fixation by means of staples or sutures may lead to severe complications. The use of fibrin sealant (FS) has been suggested as alternative, but data on biocompatibility and adhesive strength of FS in combination with macroporous meshes is limited. Ventral hernia (n = 8 per group) was treated in rats in onlay technique with two types of meshes, fibrin sealed or stapled. TI-Mesh (TMxl) extralight and VYPROII (VPII) were tested 17 days post op. No failure in mechanical tests (tensile and burst strength) occurred in sealed or stapled meshes. Histology revealed equally good tissue integration and neovascularization in all groups. Fibrin sealant yields excellent fixation in experimental hernia repair. This rat model is suitable for testing meshes and fixation techniques.

  3. Elastic sealants for surgical applications.

    PubMed

    Annabi, Nasim; Yue, Kan; Tamayol, Ali; Khademhosseini, Ali

    2015-09-01

    Sealants have emerged as promising candidates for replacing sutures and staples to prevent air and liquid leakages during and after the surgeries. Their physical properties and adhesion strength to seal the wound area without limiting the tissue movement and function are key factors in their successful implementation in clinical practice. In this contribution, the advances in the development of elastic sealants formed from synthetic and natural materials are critically reviewed and their shortcomings are pointed out. In addition, we highlight the applications in which elasticity of the sealant is critical and outline the limitations of the currently available sealants. This review will provide insights for the development of novel bioadhesives with advanced functionality for surgical applications.

  4. Chemical research projects office fuel tank sealants review. [flight testing of fluorosilicone sealants

    NASA Technical Reports Server (NTRS)

    Rosser, R. W.; Parker, J. A.

    1974-01-01

    The status of high-temperature fuel tank sealants for military and potentially commercial supersonic aircraft is examined. The interrelationships of NASA's sealants program comprise synthesis and development of new fluoroether elastomers, sealant prediction studies, flight simulation and actual flight testing of best state-of-the-art fluorosilicone sealants. The technical accomplishments of these projects are reviewed.

  5. [Healing of tubal anastomoses--microsurgery vs. fibrin gluing: morphologic aspects].

    PubMed

    Gauwerky, J F; Klose, R P; Forssmann, W G

    1994-01-01

    The healing of anastomoses either by microsurgical suture technique or by fibrin sealant technique has been examined in an experimental morphological study. With view to morphological criteria the healing of tubal anastomoses after one month is completed. Afterwards only little areas of regeneration could be found in the region of the anastomosis. These statements are valid for both types of anastomoses. In single cases a more progressive regeneration of the mucosa could be demonstrated. Using fibrin glue a more pronounced fibrosis could not be seen.

  6. Genipin-crosslinked fibrin hydrogels as a potential adhesive to augment intervertebral disc annulus repair.

    PubMed

    Schek, R M; Michalek, A J; Iatridis, J C

    2011-04-18

    Treatment of damaged intervertebral discs is a significant clinical problem and, despite advances in the repair and replacement of the nucleus pulposus, there are few effective strategies to restore defects in the annulus fibrosus. An annular repair material should meet three specifications: have a modulus similar to the native annulus tissue, support the growth of disc cells, and maintain adhesion to tissue under physiological strain levels. We hypothesized that a genipin crosslinked fibrin gel could meet these requirements. Our mechanical results showed that genipin crosslinked fibrin gels could be created with a modulus in the range of native annular tissue. We also demonstrated that this material is compatible with the in vitro growth of human disc cells, when genipin:fibrin ratios were 0.25:1 or less, although cell proliferation was slower and cell morphology more rounded than for fibrin alone. Finally, lap tests were performed to evaluate adhesion between fibrin gels and pieces of annular tissue. Specimens created without genipin had poor handling properties and readily delaminated, while genipin crosslinked fibrin gels remained adhered to the tissue pieces at strains exceeding physiological levels and failed at 15-30%. This study demonstrated that genipin crosslinked fibrin gels show promise as a gap-filling adhesive biomaterial with tunable material properties, yet the slow cell proliferation suggests this biomaterial may be best suited as a sealant for small annulus fibrosus defects or as an adhesive to augment large annulus repairs. Future studies will evaluate degradation rate, fatigue behaviors, and long-term biocompatibility.

  7. 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.

  8. 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.

  9. Introduction of a potent single-donor fibrin glue for vascular anastomosis: An animal study

    PubMed Central

    Ardakani, Mehdi Rasti; Hormozi, Abdoljalil Kalantar; Ardakani, Jalal Rasti; Davarpanahjazi, Amir Hossein; Moghadam, Ali Shayesteh

    2012-01-01

    Background: Vascular anastomosis is considered as a difficult surgical procedure. Although different alternative methods have been tried to tackle these difficulties, none were found to be successful. Commercial fibrin glue has recently been used for vascular anastomosis. However, it did not gain popularity due to some limitations such as low tensile strength, rapid removal by the immune system, and risk of transmission of blood-borne viral infections. In this article, we presented a novel method for producing single-donor human fibrin glue and determined its success rate for vascular anastomosis in an animal model. Materials ans Methods: In this study, 3 mL of single-donor fibrin sealant was prepared from 150 mL of whole blood containing 50-70 mg/mL of fibrinogen. The study was performed on 10 dogs and 5 cats. After transection of the carotid artery, both ends were anastomosed by means of 3-4 sutures (Prolene 8-0). The suture line was then sealed with one layer of the new fibrin sealant. After 3-8 weeks, the site of anastomosis was evaluated angiographically and morphologically for healing and possible complications such as thrombosis or aneurysm. Results: In evaluations 3 weeks after the surgery, all arterial anastomoses were patent in dogs, but some degree of subintimal hyperplasia was noted. After 8 weeks, all anastomoses were patent and the degree of subintimal hyperplasia was decreased. In cats on the other hand, after 4 weeks, all anastomoses were patent and subintimal hyperplasia was absent. Conclusions: Single-donor fibrin glue was a quite reliable and practical alternative to minimize suturing and therefore operative time in our animal model. This sealant can easily be obtained from the patient's whole blood. Its application in humans would require further studies. PMID:23626612

  10. [Fissure sealants--5 years of use].

    PubMed

    Azul, A M

    1990-01-01

    This study assesses the caries prevalence, retention and cost-effectiveness of a pit and fissure sealant in a children population with 622 cases, 5 years after a single application of an auto-polymerized sealant to permanent molars. The status of the sealant and the presence of caries or restaurations on the sealed teeth was assessed. In a self-controlled group of children, the prevalence of disease (caries and restaurations) was also assessed in non-sealed teeth, for comparison. The sealant application was compared with Class I-restauration with amalgam for cost-effectiveness analysis.

  11. 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

  12. Platelet interaction with polymerizing fibrin.

    PubMed

    Niewiarowski, S; Regoeczi, E; Stewart, G J; Senyl, A F; Mustard, J F

    1972-03-01

    Interaction of washed pig, rabbit, or human platelets with fibrinogen was studied during its transition to fibrin using photometric, isotopic, and electron microscopic techniques. Untreated fibrinogen and fully polymerized fibrin had no detectable effect on platelets. Fibrinogen, incubated with low concentrations of reptilase or thrombin, formed intermediate products which readily became associated with platelets and caused their aggregation. Neutralization of the thrombin did not prevent this interaction. In the absence of fibrinogen, reptilase did not affect platelets. The interaction of polymerizing fibrin with platelets was accompanied by small losses of platelet constituents (serotonin, adenine nucleotides, platelet factor 4, and lactic dehydrogenase). This loss did not appear to be the result of the platelet release reaction. Inhibitors of the release reaction or of adenosine diphosphate (ADP)-induced aggregation did not prevent the interaction of platelets with polymerizing fibrin. Apyrase or prostaglandin E(1) (PGE(1)) reduced the extent of platelet aggregation by polymerizing fibrin, but the amount of protein associated with platelets was slightly increased. The interaction of polymerizing fibrin with platelets was completely inhibited by ethylenediaminetetraacetate (EDTA) or ethylene glycol bis (beta-aminoethyl ether) N, N,N',N'-tetraacetic acid (EGTA).Fibers formed in solutions of polymerizing fibrin were larger in the presence than in the absence of washed platelets, suggesting that platelets affect fibrin polymerization. The adherence of platelets to polymerizing fibrin may be responsible for the establishment of links between platelets and fibrin in hemostatic plugs and thrombi.

  13. High performance channel injection sealant invention abstract

    NASA Technical Reports Server (NTRS)

    Rosser, R. W.; Basiulis, D. I.; Salisbury, D. P. (Inventor)

    1982-01-01

    High performance channel sealant is based on NASA patented cyano and diamidoximine-terminated perfluoroalkylene ether prepolymers that are thermally condensed and cross linked. The sealant contains asbestos and, in its preferred embodiments, Lithofrax, to lower its thermal expansion coefficient and a phenolic metal deactivator. Extensive evaluation shows the sealant is extremely resistant to thermal degradation with an onset point of 280 C. The materials have a volatile content of 0.18%, excellent flexibility, and adherence properties, and fuel resistance. No corrosibility to aluminum or titanium was observed.

  14. Sealant research for solid oxide fuel cells

    SciTech Connect

    Myles, K.M.; Bloom, I.; Krumpelt, M.; Ley, K.L.; Dorris, S.E.; Wagh, A.S.

    1993-11-01

    A suitable sealant must form strong, dense bonds with SOFC components, be compatible, be stable at 1000{degrees}C in SOFC operating environment (H{sub 2} and H{sub 2}O on anode side, O{sub 2} on cathode side), and be electrically insulating. Two types of sealants are being developed: Rigid (Mg ammonium phosphate cement) for the cell edge, and compliant (borate-based glass-ceramic) for stack-to-manifold joining. Testing of both is reported. Shrinkage of the rigid sealant needs to be reduced. Further testing is underway.

  15. Delayed cerebrospinal fluid leak after watertight dural closure with a polyethylene glycol hydrogel dural sealant in posterior fossa surgery: case report.

    PubMed

    Jito, Junya; Nitta, Naoki; Nozaki, Kazuhiko

    2014-01-01

    A polyethylene glycol (PEG) hydrogel sealant recently has been approved as an adjunct to sutured dural closure in Japan. We treated consecutive six patients with PEG hydrogel sealant in posterior fossa operation. Three of six cases suffered delayed cerebrospinal fluid (CSF) leak after watertight dural closure with the PEG hydrogel sealant, although there was no leak case which was treated with fibrin glue, before 2 years until the adoption of the new material. These patients underwent posterior fossa craniotomy and discharged without remarkable CSF leak. The pseudomeningocele under the occipital wound caused the CSF leak occurr from 5th to 7th week postoperatively. All CSF leak cases needed surgical repair. At the repair, the PEG hydrogel was liquefied and almost absorbed. A fistula on the closure line and a dead space after the absorption of the PEG hydrogel was observed. When the absorbable PEG hydrogel sealant plugs in small gaps of sutured dura, its properties to prevent adhesion might suppress healing process of dural closure, so that CSF could leak through the gaps and collect as a pseudomeningocele in the dead space after absorption of the PEG hydrogel. In posterior fossa surgery a PEG hydrogel sealant should be applied when dural edges are closed tightly without any gaps.

  16. GENIPIN-CROSSLINKED FIBRIN HYDROGELS AS A POTENTIAL ADHESIVE TO AUGMENT INTERVERTEBRAL DISC ANNULUS REPAIR

    PubMed Central

    Schek, R.M.; Michalek, A.J.; Iatridis, J.C.

    2011-01-01

    Treatment of damaged intervertebral discs is a significant clinical problem and, despite advances in the repair and replacement of the nucleus pulposus, there are few effective strategies to restore defects in the annulus fibrosus. An annular repair material should meet three specifications: have a modulus similar to the native annulus tissue, support the growth of disc cells, and maintain adhesion to tissue under physiological strain levels. We hypothesized that a genipin crosslinked fibrin gel could meet these requirements. Our mechanical results showed that genipin crosslinked fibrin gels could be created with a modulus in the range of native annular tissue. We also demonstrated that this material is compatible with the in vitro growth of human disc cells, when genipin:fibrin ratios were 0.25:1 or less, although cell proliferation was slower and cell morphology more rounded than for fibrin alone. Finally, lap tests were performed to evaluate adhesion between fibrin gels and pieces of annular tissue. Specimens created without genipin had poor handling properties and readily delaminated, while genipin crosslinked fibrin gels remained adhered to the tissue pieces at strains exceeding physiological levels and failed at 15–30%. This study demonstrated that genipin crosslinked fibrin gels show promise as a gap-filling adhesive biomaterial with tunable material properties, yet the slow cell proliferation suggests this biomaterial may be best suited as a sealant for small annulus fibrosus defects or as an adhesive to augment large annulus repairs. Future studies will evaluate degradation rate, fatigue behaviors, and long-term biocompatibility. PMID:21503869

  17. Measuring the rupture stress point of biological sealant-collagen bonding: validation of a technique used after hepatectomy.

    PubMed

    Michot, F; Scotte, M; Dujardin, F; Hoebeke, Y; Le Blanc, I; Amelot, A; Azema, P; Bouvier, P

    1993-01-01

    The aim of this experimental study was to measure the rupture stress point of a fibrin clot situated on a liver, in realistic surgical conditions. The experimental method was carried out with a machined wooden cylinder bonded on the liver, connected with a wire to a setup and pulled at a constant speed, and a sensor was placed on the wire measuring the applied strength. This method, realized in the dog, made it possible to validate a precise and reproducible method designed for testing the adhesive characteristics of biological sealant-collagen bonding on the liver.

  18. Usefulness of a new gelatin glue sealant system for dural closure in a rat durotomy model.

    PubMed

    Kawai, Hisashi; Nakagawa, Ichiro; Nishimura, Fumihiko; Motoyama, Yasushi; Park, Young-Su; Nakamura, Mitsutoshi; Nakase, Hiroyuki; Suzuki, Shuko; Ikada, Yoshito

    2014-01-01

    Watertight dural closure is imperative after neurosurgical procedures, because inadequately treated leakage of cerebrospinal fluid (CSF) can have serious consequences. We used a rat durotomy model to test the usefulness of a new gelatin glue as a dural sealant in a rat model of transdural CSF leakage. All rats were randomly divided into one of the following three treatment groups: no application (control group: N = 18), application of fibrin glue (fibrin glue group: N = 18), and application of the new gelatin glue (new gelatin glue group: N = 18). The craniotomy side was re-opened, and CSF leakage was checked and recorded at 1, 7, and 28 days postoperatively. The new gelatin glue was adequate for stopping CSF leakage; no leakage was observed at postoperative days 1 or 7, and leakage was observed in only one rat at postoperative day 28. This result was statistically significant when compared to the control group (P = 0.002, P = 0.015, P = 0.015, respectively). The pathologic score of the new gelatin group was not different from that of the control or fibrin glue groups. We conclude that our new gelatin glue provides effective watertight closure 1, 7, and 28 days after operation in the rat durotomy model.

  19. Patch tests*

    PubMed Central

    Lazzarini, Rosana; Duarte, Ida; Ferreira, Alessandra Lindmayer

    2013-01-01

    Patch tests were introduced as a diagnostic tool in the late nineteenth century. Since then, they have improved considerably becoming what they are today. Patch tests are used in the diagnostic investigation of contact dermatitis worldwide. Batteries or series previously studied and standardized should be used in patch testing. The methodology is simple, but it requires adequate training for the results to be correctly interpreted and used. Despite having been used for over a century, it needs improvement like all other diagnostic techniques in the medical field. PMID:24474094

  20. 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.

  1. A comparative study of fluoride release from two different sealants

    PubMed Central

    Ananda, Shimoga-Raju

    2014-01-01

    Objectives: The introduction of fluoride releasing sealants and glass ionomer cements as fissure sealants adds another dimension to prevention of pit and fissure caries. The ability of resin sealants and glass ionomer cements to release fluoride on a long term basis to the sealed enamel and the adjacent unsealed pit and fissure and cuspal incline enamel may allow for further reduction in pit and fissure caries experience for children. Hence, the study was conducted to compare the amount of fluoride release in the plaque after placing fluoride releasing pit and fissure sealants and glass ionomer fissure sealants used in Atraumatic Restorative Treatment (ART) approach. To compare the fluoride release of both the materials at the different time intervals. Material and Methods: A total of 60 school going children were included in this study. Before application of the sealants, baseline plaque fluoride levels were estimated from all the study subjects. After application of sealants again the same was estimated at an interval of 24 hour, 9 days, 2 weeks and 4 weeks. Results: The peak plaque fluoride levels were achieved at 24 hours after application of fissure sealants in all the groups. Conclusions: Within the limitation of the study, the present study indicated that fluoride releasing fissure sealants may act as a source of fluoride in plaque which will help in preventing pit and fissure and smooth surface caries in the tooth sealed with fissure sealants. Key words:Plaque fluoride, pit and fissures sealants, dental caries. PMID:25674315

  2. Laboratory testing of sealants with a marble substrate

    SciTech Connect

    Farmer, M.C.; Cechner, R.A.

    1996-12-31

    Polyurethane and silicone sealants are widely specified for installations with porous substrates such as some stones. However, when a sealant is used against such surfaces, there is a potential for a lack of adequate adhesion, or staining of the tone by misapplication or migration of the liquid components of the sealant system, such as primers or plasticizers in the formulation. Some varieties of marble in particular have been reported to be susceptible to staining and discoloration over time from sealants. Application of new sealant over existing sealants is also of great concern for remedial applications. Determining the level of substrate preparation necessary to achieve adequate bond is critical to the success of the remedial construction project. This paper discusses the development and results of a test program conducted to determine the relative performance of sealants installed on a white marble substrate. The tests performed included wet adhesion tests, accelerated weathering studies, and staining due to plasticizer migration.

  3. Injectible candidate sealants for fetal membrane repair: Bonding and toxicity in vitro

    PubMed Central

    Bilic, Grozdana; Brubaker, Carrie; Messersmith, Phillip B.; Mallik, Ajit S.; Quinn, Thomas M.; Haller, Claudia; Done, Elisa; Gucciardo, Leonardo; Zeisberger, Steffen M.; Zimmermann, Roland; Deprest, Jan; Zisch, Andreas H.

    2010-01-01

    Objective This study was undertaken to test injectible surgical sealants that are biocompatible with fetal membranes, eventually for closure of iatrogenic membrane defects. Study Design Dermabond, Histoacryl, Tissucol fibrin glue, and three types of in situ forming poly(ethylene glycol)-based polymer hydrogels were tested for acute toxicity upon direct contact with fetal membranes for 24h. For determination of elution toxicity, extracts of sealants were incubated on amnion cell cultures for 72h. Bonding and toxicity was assessed through morphological and/or biochemical analysis. Results Extracts of all adhesives were non-toxic for cultured cells. However, only Tissucol and one type of poly(ethylene glycol)-based hydrogel, mussel-mimetic tissue adhesive, showed efficient, non-disruptive, non-toxic bonding to fetal membranes. Mussel-mimetic tissue adhesive applied over membrane defects created with a 3.5 mm trocar accomplished leak-proof closure that withstood membrane stretch in an in vitro model. Conclusion A synthetic hydrogel-type tissue adhesive emerged as potential sealing modality for iatrogenic membrane defects that merits further evaluation in vivo. PMID:20096254

  4. In vivo evaluation of a new sealant material on a rat lung air leak model.

    PubMed

    Kobayashi, H; Sekine, T; Nakamura, T; Shimizu, Y

    2001-01-01

    The ability of an albumin-based hydrogel sealant (ABHS) to prevent air leakage through the suture line after pulmonary surgery was evaluated by comparison with that of a fibrin glue (FG). As an air-leak model, a rat lung was used in which a standard incision was made and the burst pressure for ABHS and FG was measured. The average burst pressures at time 0 for the FG and ABHS groups were 30.8+/-15.2 and 77.5 +/-19.1 mmHg, respectively. At Day 3, the value of ABHS (76.3 +/- 15.8 mmHg) was still significantly higher (P<0.05) than that of FG (60.0 +/- 21.9 mmHg). At Day 7, no statistical difference was observed between the FG group(71.2 +/- 18.6 mmHg) and the ABHS group(88.8 +/- 11.7 mmHg). Histological examination of the incision at Day 14 revealed that neither sealant was not visible at the incision site, and there was no evidence of adverse tissue reaction. It was concluded that ABHS had good sealing properties and is an alternative to FG for air leakage treatment in pulmonary surgery.

  5. Copolymer sealant compositions and method for making

    NASA Technical Reports Server (NTRS)

    Singh, Navjot (Inventor); Leman, John Thomas (Inventor); Whitney, John M. (Inventor); Krabbenhoft, Herman Otto (Inventor)

    2003-01-01

    Condensation curable poly(fluoroorgano)siloxane-poly(silarylene)siloxane block copolymer compositions having a glass transition temperature not exceeding about -54.degree. C. and excellent solvent resistance have been found useful as sealants. Polyalkoxysilylorgano compounds, such as 1,4-bis[trimethoxysilyl(ethyl)]benzene have been found to be effective as cross-linkers.

  6. Copolymer sealant compositions and method for making

    NASA Technical Reports Server (NTRS)

    Singh, Navjot (Inventor); Leman, John Thomas (Inventor); Whitney, John M. (Inventor); Krabbenhoft, Herman Otto (Inventor)

    2004-01-01

    Condensation curable poly(fluoroorgano)siloxane-poly(silarylene)siloxane block copolymer compositions having a glass transition temperature not exceeding about -54.degree. C. and excellent solvent resistance have been found useful as sealants. Polyalkoxysilylorgano compounds, such as 1,4-bis[trimethoxysilyl(ethyl)]benzene have been found to be effective as cross-linkers.

  7. Copolymer sealant compositions and method for making

    NASA Technical Reports Server (NTRS)

    Singh, Navjot (Inventor); Leman, John Thomas (Inventor); Whitney, John M. (Inventor); Krabbenhoft, Herman Otto (Inventor)

    2002-01-01

    Condensation curable poly(fluoroorgano)siloxane-poly(silarylene)siloxane block copolymer compositions having a glass transition temperature not exceeding about -54.degree. C. and excellent solvent resistance have been found useful as sealants. Polyalkoxysilylorgano compounds, such as 1,4-bis[trimethoxysilyl(ethyl)]benzene have been found to be effective as cross-linkers.

  8. Bisphenol A and Dental Sealants: Olea's Response.

    PubMed Central

    Olea, N

    2000-01-01

    Comments on "Determination of bisphenol A and related aromatic compounds released from Bis-GMA-based composites and sealants by high performance liquid chromatography." by ulgar R, Olea-Serrano MF, Novillo-Fertrell A, Rivas A, Pazos P, Pedraza V, Navajas J-M, Olea N. Environ Health Perspect 108:21-27 (2000). PMID:11133410

  9. Efficacy of fibrinogen/thrombin-coated equine collagen patch in controlling lymphatic leaks.

    PubMed

    Vida, Vladimiro L; Padalino, Massimo A; Barzon, Elisa; Stellin, Giovanni

    2012-07-01

    We report the use of fibrinogen/thrombin-coated equine collagen patch (Tachosil(®) ) as a sealant agent in six patients who underwent heart surgery for congenital heart disease (CHD) and developed an intraoperative lymphatic leakage detected at the time of surgery. The use of fibrinogen/thrombin-coated equine collagen patch proved to be safe and effective in preventing the development of postoperative chylothorax.

  10. Sustained (rh)VEGF(165) release from a sprayed fibrin biomatrix induces angiogenesis, up-regulation of endogenous VEGF-R2, and reduces ischemic flap necrosis.

    PubMed

    Mittermayr, Rainer; Morton, Tatjana; Hofmann, Martina; Helgerson, Sam; van Griensven, Martijn; Redl, Heinz

    2008-01-01

    This study investigated (1) the release of recombinant human vascular endothelial growth factor ([rh]VEGF(165)) from an in vitro fibrin matrix, (2) the effects of (rh)VEGF(165) released from an in vivo fibrin matrix on ischemic flap necrosis in the rat dorsal skin flap model, and (3) the effects of (rh)VEGF(165) released from an in vivo fibrin matrix on VEGF-R2 expression in transgenic VEGF-R2/luc mice. In vitro fibrin matrices were spiked with (rh)VEGF(165) and demonstrated (rh)VEGF(165) release over 88 hours with 66% recovery. Ischemic dorsal flaps were treated with a fibrin sealant (FS), FS spiked with (rh)VEGF(165), or left untreated. Flaps treated with FS spiked with (rh)VEGF(165) showed greater viability than controls as measured by planimetric analysis. Immunohistochemical analyses revealed stronger neovascularization than that exhibited by controls. Transgenic mice implanted with FS spiked with (rh)VEGF(165) had significant increases in VEGF-R2 expression relative to controls at days 5-13 after implantation. Conclusions drawn from this work are that (1) (rh)VEGF(165) is released from an in vitro fibrin matrix at clinically appropriate times, (2) (rh)VEGF(165) increases the viability of tissue flaps in vivo, and (3) (rh)VEGF(165) induces the expression of VEGF-R2 expression. This work demonstrates the clinical ability of sprayed FS to locally deliver growth factors to ischemic tissue of patients.

  11. Retention of sealants placed by dental technicians without assistance.

    PubMed

    Foreman, F J; Matis, B A

    1991-01-01

    The retention rate of sealants placed by dental auxiliaries has not been studied extensively. This study recorded and compiled the retention rate of sealants placed by Air Force dental technicians over a two-year period. The technicians, who were equivalent to dental assistants, were trained to place the sealants without assistance using the Vac-Ejector (Whaledent International, New York, NY) system for isolation. Five hundred and ninety-nine sealants on 90 patients were evaluated an average of 13.9 months after sealant placement. The overall complete retention rate was 91.0%, with a partial loss rate of 7.0%, and a complete loss rate of 2.0%. These results suggest that pit and fissure sealants can be placed in this cost-effective manner with a relatively high retention rate.

  12. Thermally resistant polymers for fuel tank sealants

    NASA Technical Reports Server (NTRS)

    Webster, J. A.

    1973-01-01

    Imide-linked perfluoroalkylene ether polymers, that were developed for the high temperature fuel tank sealant application, are discussed. Modifications of polymer structure and properties were realized through use of a new aromatic dianhydride intermediate containing an ether-linked perfluoroalkylene segment. Tests of thermal, oxidative and hydrolytic stability, fuel resistance, and adhesion are discussed along with tensile strength and elongation results. Efforts to effect a low temperature condensation of amic acid prepolymer to form imide links inside are described.

  13. Cryogenic adhesives and sealants: Abstracted publications

    NASA Technical Reports Server (NTRS)

    Williamson, F. R.; Olien, N. A.

    1977-01-01

    Abstracts of primary documents containing original experimental data on the properties of adhesives and sealants at cryogenic temperatures are presented. The most important references mentioned in each document are cited. In addition, a brief annotation is given for documents considered secondary in nature, such as republications or variations of original reports, progress reports leading to final reports included as primary documents, and experimental data on adhesive properties at temperatures between about 130 K and room temperature.

  14. Fibrin Sealant Foam Sprayed Directly on Liver Injuries Decreases Blood Loss in Resuscitated Rats

    DTIC Science & Technology

    2000-08-01

    produced and whether foam in the abdo - men prevents the subsequent operating surgeon from identifying injured structures. Delivery devices and optimal... CT : Greenwood Press; 1992. 7. Bellamy RF. The causes of death in conventional land warfare: implications for combat casualty care research. Mil Med

  15. The Potential Utility of Fibrin Sealant Dressing in Repair of Vascular Injury in Swine

    DTIC Science & Technology

    2007-01-12

    and veterinarian staff. Prophylactic antibiotics (Naxcel, ceftiofur sodium) were given intramus- cularly once a day for 3 days. Postoperative pain was...unexpectedly. Statistical Analysis The Kruskal-Wallis test (nonparametric ANOVA) was used for comparison of pre- and postoperative hematological ...ment was counted as a successful test in the 8-week group. Hemostasis results are summarized in Table 1. Hematological Measurements The hematological

  16. Carrier-bound fibrin sealant compared to oxidized cellulose application after liver resection

    PubMed Central

    Zacharias, Thomas; Ferreira, Nelio

    2012-01-01

    Objective The aim of the study was to compare the incidence of post-operative complications between those patients that received TachoSil® to the transection surface of the liver vs. those that received Surgicel®. Methods Retrospective study of a prospective database in a tertiary hospital. Primary endpoints were overall complications. Secondary endpoints were liver surgery-specific composite endpoint, major complications and hospital stay. Uni- and multivariate analysis of predictive factors for complications and subgroup analysis were performed. Results One hundred thirty-three liver resections were performed between 9 November 2007 and 2 November 2011: 64 with TachoSil® and 69 with Surgicel® application. Both groups were equivalent concerning demographic, clinical and major intra-operative data. No significant differences were observed in overall complication rate (62.5% vs. 62.3%), liver surgery-specific composite endpoint (12.5% vs. 18.8%), major complication rate (18.7% vs. 24.6%) and median hospital stay (13 vs. 10 days) for TachoSil® and Surgicel® application, respectively. Predictive factors for complications in multivariate analysis were: American Society of Anesthesiology Score ≥3 and duration of surgery >240 min. Subgroup analysis found a reduced complication rate with TachoSil® for major hepatectomy. Conclusion The results of the present study suggest that the routine use of TachoSil® after a liver resection does not reduce the overall complication rate compared with Surgicel® application. However, TachoSil® may be beneficial in a major hepatectomy. PMID:23134186

  17. Viscous Glass Sealants for SOFC Applications

    SciTech Connect

    Scott Misture

    2012-09-30

    Two series of silicate glasses that contain gallium as the primary critical component have been identified and optimized for viscous sealing of solid oxide fuel cells operating from 650 to 850°C. Both series of glass sealants crystallize partially upon heat treatment and yield multiphase microstructures that allow viscous flow at temperatures as low as 650°C. A fully amorphous sealant was also developed by isolating, synthesizing and testing a silicate glass of the same composition as the remnant glassy phase in one of the two glass series. Of ~40 glasses tested for longer than 500 hours, a set of 5 glasses has been further tested for up to 1000h in air, wet hydrogen, and against both yttria-stabilized zirconia and aluminized stainless steel. In some cases the testing times reached 2000h. The reactivity testing has provided new insight into the effects of Y, Zr, and Al on bulk and surface crystallization in boro-gallio-silicate glasses, and demonstrated that at least 5 of the newly-developed glasses are viable viscous sealants.

  18. Marginal Microleakage of Conventional Fissure Sealants and Self-Adhering Flowable Composite as Fissure Sealant in Permanent Teeth

    PubMed Central

    Rahimian-Imam, Sara; Fayazi, Mohammad Reza

    2015-01-01

    Objectives: Application of sealants is a safe and effective way to prevent occlusal caries in the posterior teeth. A successful sealant therapy depends on good isolation. Decreased steps of adhesive application may enable proper isolation and use of self-adhering flowable composites for sealant therapy. This study sought to compare the marginal microleakage of fissure sealants and self-adhering flowable composites in permanent teeth. Materials and Methods: This in vitro, experimental study was conducted on 60 extracted human premolar teeth. The teeth were divided randomly into two groups of 30. In the first group, fissure sealant (Clinpro, 3M ESPE, USA) was placed on the teeth. In the second group, self-adhering flowable composite (Vertise Flow, Kerr, USA) was applied as the sealant. Then, both groups were immersed in 0.5% fuchsin dye solution for 24 hours. Sectioned samples were observed with a stereomicroscope for the extent of dye penetration. Data were analyzed using SPSS 21 and the Mann-Whitney test (P<0.05). Results: Microleakage in the fissure sealant group was significantly higher than that in the self-adhering flowable composite group (P<0.001). Conclusion: Microleakage was less using self-adhering flowable composite compared to conventional fissure sealant; therefore, self-adhering flowable composite can be used as a suitable fissure sealant in permanent teeth. PMID:26884777

  19. 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

  20. The Maine Sealant Manual for School-Based and School-Linked Dental Sealant Programs.

    ERIC Educational Resources Information Center

    Hayward, Kneka, Ed.

    This manual is designed for use by school personnel and dental personnel to aid in the development and maintenance of school-based or school-linked dental sealant programs. The sections include (1) "Introduction"; (2) "Guidelines" (school selection, school contacts, dental providers, target grades, and tooth selection…

  1. Iodixanol as a Contrast Agent in a Fibrin Hydrogel for Endodontic Applications

    PubMed Central

    Hertig, Gabriel; Zehnder, Matthias; Woloszyk, Anna; Mitsiadis, Thimios A.; Ivica, Anja; Weber, Franz E.

    2017-01-01

    The application of biomaterials used in regenerative endodontics should be traceable. In this study, we checked some basic effects of rendering a fibrin hydrogel radiopaque using an iodine-based contrast agent (iodixanol) approved for systemic application. Fibrin hydrogels were prepared from a fibrin sealant (Tisseel) using either an isotonic iodixanol solution (Visipaque 320, test) or Tris buffer (control) as a diluent. Gelation kinetics, radiopacity, and swelling of lyophilized hydrogels were tested using standard methods. Hydrogel structure was evaluated using scanning electron microscopy (SEM). Furthermore, iodixanol release from the test gels was assessed using spectrophotometry, and tissue compatibility was compared between test and control hydrogels using the chick chorioallantoic membrane (CAM) assay. Results were compared using pairwise t-test, p < 0.05. Iodixanol caused a 70-fold delay in gelation to 26 min in the test compared to the control hydrogels (22 ± 1 s). Radiopacity of the test gels was 1.9 ± 0.2 mm Al/mm, compared to zero in the control hydrogels. Lyophilized hydrogel swelling was strongly reduced when iodixanol was added to the hydrogel (p < 0.05). Test hydrogels had an altered SEM appearance compared to controls, and exhibited a reduced porosity. Iodixanol release from the test hydrogels reached 14.5 ± 0.5% after 120 h and then ceased. This release did not have any apparent toxic effect and neither affected the viability, nor the physiology or vascularization of the CAM of fertilized chicken eggs. Iodixanol can render a fibrin hydrogel radiopaque and maintains its tissue compatibility, yet impacts gelation kinetics and hydrogel porosity. PMID:28360862

  2. Silicone Rubber Superstrate Loaded Patch Antenna Design Using Slotting Technique

    NASA Astrophysics Data System (ADS)

    Kaur, Bhupinder; Saini, Garima; Saini, Ashish

    2016-09-01

    For the protection of antenna from external environmental conditions, there is a need that antenna should be covered with a stable, non-reactive, highly durable and weather resistive material which is insensitive to changing external environment. Hence, in this paper silicone rubber is proposed as a superstrate layer for patch antenna for its protection. The electrical properties of silicon rubber sealant are experimentally found out and its effect of using as superstrate on coaxial fed microstrip patch antenna using transmission line model is observed. The overall performance is degraded by slightly after the use of superstrate. Further to improve the performance of superstrate loaded antenna, patch slots and ground defects have been proposed. The proposed design achieves the wideband of 790 MHz (13.59 %), gain of 7.12 dB, VSWR of 1.12 and efficiency of 83.02 %.

  3. Viscoseal performance with rarefied-gas sealant

    NASA Technical Reports Server (NTRS)

    Milligan, M. W.

    1973-01-01

    A fundamental study of viscoseals having a rarefied gas as the sealant was conducted. Both experimental and analytical investigations are reported. Three different analytical models were formulated and are described in detail. An experimental investigation was conducted on multiple grooved two-inch diameter viscoseals over a wide range of gas densities and shaft speeds up to 30,000 rpm. Comparisons are presented between actual viscoseal performance and the theoretical predictions for both sealing coefficient and net leakage parameters as functions of the degree of gas rarefication. Recommendations are presented for the use of the analytical models.

  4. Sealant materials for solid oxide fuel cells

    SciTech Connect

    Krumpelt, M.

    1995-08-01

    The objective of this work is to complete the development of soft glass-ceramic sealants for the solid oxide fuel cell (SOFC). Among other requirements, the materials must soften at the operation temperature of the fuel cell (600-1000{degrees}C) to relieve stresses between stack components, and their thermal expansions must be tailored to match those of the stack materials. Specific objectives included addressing the needs of industrial fuel cell developers, based on their evaluation of samples we supply, as well as working with commercial glass producers to achieve scaled-up production of the materials without changing their properties.

  5. Granisetron Transdermal Patch

    MedlinePlus

    ... patch. Each patch is stuck onto a thin plastic liner and a separate rigid plastic film. Do not open the pouch in advance, ... cut the patch into pieces. Peel the thin plastic liner off of the printed side of the ...

  6. Cabbage Patch

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This Sojourner rover image of the Cabbage Patch shows small rounded objects on the surface that are about 3-4 cm across. Some of these are within excavations, which are about 0.5 cm wide. Several questions arise about the pebbles: Why are they rounded? Where did they come from? What do they mean?

    Geologists use MULTIPLE WORKING HYPOTHESES when attempting to explain observations. Some hypotheses that could account for the pebbles are: They were rounded during transport by waters of catastrophic floods and deposited on the Ares Vallis floodplain They were rounded by wave action on an ancient Martian beach They were rounded during glacial transport They are glasses that were produced by melting during impact cratering. The glass was first ejected from the crater, then molded into spherical shapes or drops as it traveled through the atmosphere, and finally was deposited at the sites They are spatter from lava flows They are nodules brought up from the deep Martian interior by lava flows or pyroclastic eruptions. They are concretions formed in sedimentary rocks They came from ancient conglomerate rocks. The pebbles were rounded by water action and subsequently lithified into conglomerate rocks. Later, the waters of catastrophic floods transported the conglomerates and deposited them on the Ares floodplain. The pebbles were then freed from the rocks by weathering. A combination of the above

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

  7. Orbiter Reinforced Carbon-Carbon Advanced Sealant Systems: Screening Tests

    NASA Technical Reports Server (NTRS)

    Curry, Donald M.; Lewis, Ronad K.; Norman, Ignacio; Chao, Dennis; Nicholson, Leonard S. (Technical Monitor)

    2000-01-01

    Oxidation protection for the Orbiter reinforced carbon-carbon (RCC consists of three components: silicon carbide coating, tetraethyl orthosilicate (TEOS) impregnated into the carbon substrate and a silicon based surface sealant (designated Type A). The Orbiter Type A sealant is being consumed each mission, which results in increased carbon-carbon substrate mass loss, which adversely impacts the mission life of the RCC components. In addition, the sealant loss in combination with launch pad contamination (salt deposit and zinc oxide) results in RCC pinholes. A sealant refurbishment schedule to maintain mission life and minimize affects of pin hole formation has been implemented in the Orbiter maintenance schedule. The objective of this investigation is to develop an advanced sealant system for the RCC that extends the refurbishment schedule by reducing sealant loss/pin hole formation and that can be applied to existing Orbiter RCC components. This paper presents the results of arc jet screening tests conducted on several sealants that are being considered for application to the Orbiter RCC.

  8. Fibrin glue‐assisted glaucoma drainage device surgery

    PubMed Central

    Kahook, M Y; Noecker, R J

    2006-01-01

    Aim To describe the use of fibrin glue as a suture substitute for portions of glaucoma drainage device (GDD) surgery. Methods Retrospective non‐randomised case–control study reviewing 28 consecutive cases of GDD implantation using traditional suture material compared with 14 consecutive cases of GDD implantation using Tisseel fibrin glue (Baxter AG, Vienna, Austria) for portions of the procedure. The fibrin glue was used to close the conjunctiva, secure the pericardium patch graft and secure the tube to the sclera. Three‐month follow‐up data for each group as well as data on operating times, postoperative conjunctival inflammation, drugs used for glaucoma and intraocular pressure (IOP) were evaluated. Statistical analysis was carried out using analysis of variance. Results The mean (SD) age of the patients in the suture group (17 men and 11 women) was 56.6 (10.5) years and that in the Tisseel‐assisted group (8 men and 6 women) was 54.7 (8.6) years (p = 0.56). No significant differences were observed in IOP levels at any time point between the two groups. No significant differences were found for the need for postoperative glaucoma drops or postoperative complication rates in both groups. Conjunctival inflammation was more pronounced in the suture group (p = 0.002) using a standard scale for comparison. The mean (SD) time of surgery was significantly less for the Tisseel‐assisted group, 15.0 (3.11) min, than for the suture group, 25.93 (4.04) min (p<0.001). Conclusions Tisseel fibrin glue seems to be a safe substitute for some of the sutures used in GDD surgery. Use of Tisseel seems to have no effect on IOP control or complications, whereas it considerably improved postoperative conjunctival inflammation and reduced time of surgery. Further studies are needed to better understand the role of fibrin glue in GDD implantation. PMID:16916877

  9. Fibrin biomatrix-conjugated platelet-derived growth factor AB accelerates wound healing in severe thermal injury.

    PubMed

    Mittermayr, Rainer; Branski, Ludwik; Moritz, Martina; Jeschke, Marc G; Herndon, David N; Traber, Daniel; Schense, Jason; Gampfer, Jörg; Goppelt, Andreas; Redl, Heinz

    2016-05-01

    Controlled delivery of growth factors from biodegradable biomatrices could accelerate and improve impaired wound healing. The study aim was to determine whether platelet-derived growth factor AB (PDGF.AB) with a transglutaminase (TG) crosslinking substrate site released from a fibrin biomatrix improves wound healing in severe thermal injury. The binding and release kinetics of TG-PDGF.AB were determined in vitro. Third-degree contact burns (dorsum of Yorkshire pigs) underwent epifascial necrosectomy 24 h post-burn. Wound sites were covered with autologous meshed (3:1) split-thickness skin autografts and either secured with staples or attached with sprayed fibrin sealant (FS; n = 8/group). TG-PDGF.AB binds to the fibrin biomatrix using the TG activity of factor XIIIa, and is subsequently released through enzymatic cleavage. Three doses of TG-PDGF.AB in FS (100 ng, 1 µg and 11 µg/ml FS) were tested. TG-PDGF.AB was bound to the fibrin biomatrix as evidenced by western blot analysis and subsequently released by enzymatic cleavage. A significantly accelerated and improved wound healing was achieved using sprayed FS containing TG-PDGF.AB compared to staples alone. Low concentrations (100 ng-1 µg TG-PDGF.AB/ml final FS clot) demonstrated to be sufficient to attain a nearly complete closure of mesh interstices 14 days after grafting. TG-PDGF.AB incorporated in FS via a specific binding technology was shown to be effective in grafted third-degree burn wounds. The adhesive properties of the fibrin matrix in conjunction with the prolonged growth factor stimulus enabled by this binding technology could be favourable in many pathological situations associated with wound-healing disturbances. Copyright © 2013 John Wiley & Sons, Ltd.

  10. Piezoelectric inkjet printing of medical adhesives and sealants

    NASA Astrophysics Data System (ADS)

    Boehm, Ryan D.; Gittard, Shaun D.; Byrne, Jacqueline M. H.; Doraiswamy, Anand; Wilker, Jonathan J.; Dunaway, Timothy M.; Crombez, Rene; Shen, Weidian; Lee, Yuan-Shin; Narayan, Roger J.

    2010-07-01

    Piezoelectric inkjet printing is a noncontact process that enables microscale processing of biological materials. In this research summary, the use of piezoelectric inkjet printing for patterning medical adhesives and sealants, including a two-component polyethylene glycol hydrogel-based medical sealant, an N-butyl cyanoacrylate tissue adhesive, and a mussel adhesive protein biological adhesive, is described The effect of Fe(III) on mussel adhesive protein structure was evaluated by means of atomic force microscopy. The ability to process microscale patterns of medical sealants and adhesives will provide an improvement in tissue joining, including enhanced tissue integrity, reduced bond lines, and decreased adhesive toxicity. Piezoelectric inkjet deposition of medical adhesives and sealants may be used in wound closure, fracture fixation, and microscale vascular surgery.

  11. Near-infrared imaging of demineralization under sealants

    NASA Astrophysics Data System (ADS)

    Tom, Henry; Simon, Jacob C.; Chan, Kenneth H.; Darling, Cynthia L.; Fried, Daniel

    2014-07-01

    Previous studies have shown that near-infrared (NIR) reflectance and transillumination imaging can be used to acquire high contrast images of early caries lesions and composite restorative materials. The aim of the study was to determine the optimum NIR wavelengths for imaging demineralized areas under dental sealants. Fifteen natural human premolars and molars with occlusal lesions were used in this in vitro study. Images before and after application of sealants were acquired using NIR reflectance and NIR transillumination at wavelengths of 1300, 1460, and 1500 to 1700 nm. Images were also acquired using polarization sensitive optical coherence tomography (OCT) for comparison. The highest contrast for NIR reflectance was at 1460 nm and 1500 to 1700 nm. These NIR wavelengths are coincident with higher water absorption. The clear Delton sealant investigated was not visible in either copolarization or cross-polarization OCT images. The wavelength region between 1500 and 1700 nm yielded the highest contrast of lesions under sealants for NIR reflectance measurements.

  12. Fluoride concentration from dental sealants: a randomized clinical trial.

    PubMed

    Campus, G; Carta, G; Cagetti, M G; Bossù, M; Sale, S; Cocco, F; Conti, G; Nardone, M; Sanna, G; Strohmenger, L; Lingström, P

    2013-07-01

    A randomized clinical trial was performed in schoolchildren (6-7 yrs) to evaluate fluoride concentration in interproximal fluid after the placement of 3 different sealants. The sample consisted of 2,776 children randomly divided: 926 in the high-viscosity Glass-ionomer Cement group (GIC group), 923 in the fluoride Resin-based group (fluoride-RB group), and 927 in the no-fluoride Resin-based group (RB group). In total, 2,640 children completed the trial. Sealants were applied following manufacturer's instructions. Interproximal fluid samples were collected at baseline and 2, 7, and 21 days after application of sealants, by insertion of a standardized paperpoint into the interproximal mesial space of the sealed tooth for 15 seconds. Fluoride concentration was evaluated by means of a fluoride ion-selective electrode. At 2 days after sealant application, fluoride concentration was significantly higher in GIC and fluoride-RB groups compared with that in the RB group (p < .01). Mean fluoride concentrations after 7 days were 2.54 (SE 0.68) ppm, 0.85 (SE 0.26) ppm, and 0.53 (SE 0.11) ppm for the three groups, respectively. After 21 days, fluoride concentration in the GIC group remained higher than that in the other two groups. High-viscosity GIC sealants increased the fluoride concentrations in interproximal fluid more than did a Resin-based sealant containing fluoride.

  13. S53P4 bioactive glass and fibrin glue for the treatment of osteochondral lesions of the knee - a preliminary in vivo study in rabbits.

    PubMed

    Zazgyva, AncuŢa Marilena; Gurzu, Simona; Jung, Ioan; Nagy, Örs; Mühlfay, Gheorghe; Pop, Tudor Sorin

    2015-01-01

    The role of the subchondral bone and the importance of treating both bone and cartilage in cases of chondral and osteochondral lesions of the knee have been highly emphasized. There are no current studies on the experimental use of bioactive glass S53P4 (BonAlive®) as granules in the treatment of osteochondral lesions of the knee. Our preliminary study was designed to establish an experimental model and assesses the effect of glass granules fixed with fibrin compared to fibrin alone as fillers of the osteochondral defects created in the weight-bearing and partial weight-bearing regions of the distal femur in six adult rabbits. We found that the size of the distal femur in adult domestic rabbits allows the creation of 4 mm diameter and 5 mm deep osteochondral defects on both the medial femoral condyle and the trochlea, bilaterally, without significantly affecting the activity level of the animals. Retention of the glass granules in the defects was achieved successfully using a commercially available fibrin sealant. At five weeks post-implantation, we found macroscopic and microscopic differences between the four types of defects. The use of bioactive glass S53P4 for filling condylar osteochondral defects in rabbit femora led to the initiation of an early bone repair process, observed at five weeks after implantation, while the filling of trochlear defects with fibrin glue resulted in the appearance of cartilaginous tissue characteristic of endochondral ossification.

  14. Scopolamine Transdermal Patch

    MedlinePlus

    ... patch from its protective pouch. To expose the adhesive surface of the patch, the clear plastic protective ... peeled off and discarded. Contact with the exposed adhesive layer should be avoided to prevent contamination of ...

  15. SafePatch

    SciTech Connect

    Kelley, M.; Elko, S.

    2000-10-01

    Authenticating and upgrading system software plays a critical role in information security, yet practical tools for assessing and installing software are lacking in today's marketplace. The SafePatch tool provides the mechanism of performing automated analysis, notification, distribution, and installation of security patches and related software to network-based computer systems in a vendor-independent fashion. SafePatch assists in the authentication of software by comparing the system's objects with the patch's objects. SafePatch will monitor vendor's sites to determine when new patches are released and will upgrade system software on target systems automatically. This paper describes the design of SafePatch, motivations behind the project and the advantages of SafePatch over existing tools.

  16. Metal Patch Antenna

    NASA Technical Reports Server (NTRS)

    Chamberlain, Neil F. (Inventor); Hodges, Richard E. (Inventor); Zawadzki, Mark S. (Inventor)

    2012-01-01

    Disclosed herein is a patch antenna comprises a planar conductive patch attached to a ground plane by a support member, and a probe connector in electrical communication with the conductive patch arranged to conduct electromagnetic energy to or from the conductive patch, wherein the conductive patch is disposed essentially parallel to the ground plane and is separated from the ground plane by a spacing distance; wherein the support member comprises a plurality of sides disposed about a central axis oriented perpendicular to the conductive patch and the ground plane; wherein the conductive patch is solely supported above the ground plane by the support member; and wherein the support member provides electrical communication between the planer conductive patch and the ground plane.

  17. Technology Solutions Case Study: Ducts Sealing Using Injected Spray Sealant

    SciTech Connect

    2014-03-01

    In multifamily and attached buildings, traditional duct sealing methods are often impractical or costly and disruptive because of the difficulty in accessing leakage sites. In this project, the Raleigh Housing Authority worked with Building America team, the Advanced Residential Integrated Solutions Collaborative to determine the most cost-effective ways to reduce duct leakage in its low-rise housing units.Two retrofit duct sealing techniques—manually-applied sealants and injecting a spray sealant—were implemented in several low-rise multiunit buildings. An analysis on the cost and performance of the two methods are presented. Each method was used in twenty housing units: approximately half of each group of units are single story and the remainder two-story. Results show that duct leakage to the outside was reduced by an average of 59% through the use of manual methods, and by 90% in the units where the injected spray sealant was used. Ihe cost of manually-applying sealant ranged from $275 to $511 per unit and for the injected spray sealant the cost was $700 per unit. Modeling suggests a simple payback of 2.2 years for manual sealing and 4.7 years for the injected spray sealant system. Utility bills were collected for one year before and after the retrofits. Utility bill analysis shows 14% and 16% energy savings using injected spray sealant system and hand sealing procedure respectively in heating season whereas in cooling season, energy savings using injected spray sealant system and hand sealing were both 16%.

  18. Birth Control Patch

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Patch KidsHealth > For Teens > Birth Control Patch A A A What's in this article? ... Much Does It Cost? What Is It? The birth control patch is a thin, beige, 1¾-inch (4½- ...

  19. Birth Control Patch

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Patch KidsHealth > For Teens > Birth Control Patch Print A A A What's in this ... Much Does It Cost? What Is It? The birth control patch is a thin, beige, 1¾-inch (4½- ...

  20. Retention of a resin-based sealant and a glass ionomer used as a fissure sealant in children with special needs

    PubMed Central

    Nualart-Grollmus, Zacy-Carola

    2014-01-01

    Objectives: The aim of this research is to evaluate the retention of sealants of resin and resin-modified ionomeric glass pits and fissures, on first permanent molars of special patients. Material and Methods: The sample was comprised by 32 children. The ages were between 7 and 18 years. The sealing procedure was made with the relative isolation of the molars to be sealed, through the use of cotton rolls. Two molars were sealed with Clinpro Sealant 3M Dental and the others with Vitremer. Checking of the sealants was made after 3 and 6 months of their placement, evaluating with 3 values: TR: Totally Restrained; PR: Partially Restrained; and CL: Completely Lost. Results: 67.18% of the resinous sealants, and 70.31% of the glass ionomer sealants were successful after three months. After six months, 57.81% of the resin-based sealants and 51.56% of the glass ionomer sealants were successful. When performing the Chi-square statistical analysis (P<0.05) no statistical significance was observed after 6 months. Conclusions: The retention of the resin sealant was similar to that of the glass ionomer cement at the end of six months and the retention of sealants on maxillary teeth was higher than on mandibular teeth. Key words:Sealant, glass ionomer, retention, caries, special needs. PMID:25674325

  1. Flow characteristics and sealing ability of fissure sealants.

    PubMed

    Barnes, D M; Kihn, P; von Fraunhofer, J A; Elsabach, A

    2000-01-01

    This study evaluated the relationship between fissure sealant viscosity, leakage prevention and the incidence of void formation of five commercially available pit-and-fissure sealants. Seventy-two intact, caries free human pre-molars and molars were divided into six test groups of 12 teeth each. All teeth were cleaned with a flour of pumice prophylaxis followed by etching for 60 seconds with 37% H3PO4, rinsing for 30 seconds and drying with oil-free air. Five commercial, light-cured fissure sealants and an unfilled version of one sealant were applied following manufacturers' instructions. Teeth were thermal cycled for 5000 cycles from 5-50 degrees C with a one-minute dwell time at each temperature. Silver nitrate staining followed by mesiodistal sectioning was performed. Leakage and void formation were evaluated at X50 optical magnification. Viscosity was assessed by syringing the fissure sealants into short pipettes, allowing free flow for 30 seconds and then light curing for one minute. The length of unfilled capillary was measured with a Vernier gauge. All experimental data was subjected to a one-way ANOVA, and where differences were detected, they were identified by a post hoc Tukey hsd test at a priori alpha = 0.05. Based on the conditions of the study, viscosity and flow characteristics had no effect on sealing ability or void formation.

  2. 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.

  3. Structural Hierarchy Governs Fibrin Gel Mechanics

    PubMed Central

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

    2010-01-01

    Abstract 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. PMID:20483337

  4. Safety and usability of hemostats, sealants, and adhesives.

    PubMed

    Burks, Sandra; Spotnitz, William

    2014-08-01

    Hemostats, sealants, and adhesives are an integral part of surgical patient care. Nurses who have knowledge about these agents can better help ensure safe, efficient surgical patient care. As a caregiver and patient advocate, the perioperative nurse must understand the most current information about these agents and be prepared to facilitate the transfer of this knowledge to all caregivers. Information about these agents, including the contraindications, warnings, and precautions associated with their use as well as their preparation and application, is provided here. Algorithms designed to clarify the best options for using hemostats, sealants, and adhesives are included as well.

  5. Microleakage and shear bond strength of a new sealant containing prereacted glass ionomer particles.

    PubMed

    Durham, Samuel N; Meyers, Erik J; Bailey, Clifton W; Vandewalle, Kraig S

    2017-01-01

    A new fluoride-releasing sealant system is claimed to allow easier and faster placement while providing high bond strengths without the need for phosphoric acid etching. A study was designed to compare the microleakage and shear bond strength of a self-etching, Giomer-based sealant system with those of a traditional resin sealant. Group 1 received traditional sealant applied after use of a 35% phosphoric acid etchant; group 2 received Giomer sealant after use of a self-etching primer; and group 3 received Giomer sealant after the addition of an initial phosphoric acid etching step and placement of the primer. The sealants were placed in the occlusal pits and fissures of extracted human third molars, thermocycled, placed in dye, and sectioned. The extent of microleakage (dye penetration) was expressed as a percentage of the cross-sectional length of the sealed interface. The sealants were also bonded to the facial enamel of bovine incisors. Specimens were thermocycled and tested in shear mode in a universal testing machine. The new self-etching sealant demonstrated significantly greater microleakage (P < 0.017) and lower bond strength (P < 0.05) than both the traditional sealant system and the new system when placed with phosphoric acid etchant. Phosphoric acid etching significantly improved the shear bond strength and reduced the microleakage of the new sealant.

  6. Fibroblast migration in fibrin gel matrices.

    PubMed Central

    Brown, L. F.; Lanir, N.; McDonagh, J.; Tognazzi, K.; Dvorak, A. M.; Dvorak, H. F.

    1993-01-01

    In healing wounds and many solid tumors, locally increased microvascular permeability results in extravasation of fibrinogen and its extravascular coagulation to form a fibrin gel, with concomitant covalent cross-linking of fibrin by factor XIIIa. Subsequently, inflammatory cells, fibroblasts, and endothelial cells migrate into the gel and organize it into granulation tissue and later into mature collagenous connective tissue. To gain insight into some of the cell migration events associated with these processes, we developed a quantitative in vitro assay that permits the study of fibroblast migration in fibrin gels. Early passage human or rat fibroblasts were allowed to attach to tissue culture dishes and then were overlaid with a thin layer of fibrinogen that was clotted with thrombin. Fibroblasts began to migrate upwards into the fibrin within 24 hours and their numbers and the distance migrated were quantified over several days. The extent of fibroblast migration was affected importantly by the nature of the fibrin clot. Fibroblasts migrated optimally into gels prepared from fibrinogen at concentrations of -3 mg/ml; ie, near normal plasma fibrinogen levels. Migration was greatly enhanced by extensive cross-linking of the fibrin alpha-chains by factor XIIIa, as occurs when clotting takes place in vivo. When fibrinogen was clotted in Dulbecco's modified Eagle's medium, gamma-chains were cross-linked, but alpha-chain cross-linking was strikingly inhibited, and fibroblasts migrated poorly. Gels prepared from factor XIII-depleted fibrinogen exhibited neither alpha-nor gamma-chain cross-linking and did not support fibroblast migration. Further purification of fibrinogen by anion exchange high pressure liquid chromatography depleted fibrinogen of fibronectin, plasminogen, and other impurities; this purified fibrinogen clotted to form fibrin gels that supported reproducible fibroblast migration. Images Figure 1 Figure 2 Figure 4 Figure 6 PMID:8424460

  7. 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.

  8. Dental Pit and Fissure Sealants: Implications for School Health Personnel.

    ERIC Educational Resources Information Center

    McCormack-Brown, K. R.; And Others

    1989-01-01

    To promote good personal hygiene practices in students, school health personnel must be informed about dental pit and fissure sealants and related programs. Adoption and maintenance of such programs may depend on the success of school health personnel in educating administrators and policymakers. (SM)

  9. Near-IR imaging of demineralization under sealants

    NASA Astrophysics Data System (ADS)

    Tom, Henry; Chan, Kenneth H.; Darling, Cynthia L.; Fried, Daniel

    2014-02-01

    Previous studies have shown that near-IR reflectance and transillumination imaging can be used to acquire high contrast images of early caries lesions and composite restorative materials. The aim of the study was to determine the optimum near-IR wavelengths for imaging demineralized areas under dental sealants. Fifteen natural human premolars and molars with occlusal lesions were used in this in vitro study. Images before and after application of sealants were acquired using near-IR reflectance and near-IR transillumination at wavelengths of 1300 nm, 1460 nm, and 1500 - 1700 nm. Images were also acquired using polarization sensitive optical coherence tomography for comparison. The highest contrast for near- IR reflectance was at 1460 nm and 1500 - 1700 nm. These near-IR wavelengths are coincident with higher water absorption. The clear Delton sealant investigated was not visible in either co-polarization or crosspolarization OCT images. The wavelength region between 1500-1700-nm yielded the highest contrast of lesions under sealants for near-IR reflectance measurements.

  10. Bond strength of Bis-GMA and glass ionomer pit and fissure sealants using cyclic fatigue.

    PubMed

    Dewji, H R; Drummond, J L; Fadavi, S; Punwani, I

    1998-02-01

    The aim of the study was to determine the bond strength of glass ionomer and resin-modified glass ionomer sealants compared to Bis-GMA sealants using both static and cyclic fatigue shear testing. Four materials were evaluated: D, a Bis-GMA sealant with 10% phosphoric acid etchant; FC, a resin-modified glass ionomer sealant with 20% polyacrylic acid etchant; FD, a resin-modified glass ionomer sealant with 10% polyacrylic acid etchant; and FSC, a self-cured glass ionomer sealant with no etchant. Gelatin capsules filled with the sealant material were bonded to the enamel surfaces of bovine teeth after appropriate surface conditioning and then tested in shear static and cyclic fatigue. Static and cyclic shear bond strengths, respectively, for each group were (MPa): FC: 21.1+/-2.8 and 17.1+/-3.1; FD: 14.6+/-5.9 and 8.5+/-3.1; D: 10.8+/-4.9 and 4.7+/-2.6; FSC: 8.7 (1.0 and 2.9+/-0.6. The resin-modified glass ionomer sealants had better fatigue bond strength than both Bis-GMA and self-cured glass ionomer sealants with the surface conditioning affecting the bond strength of the resin-modified glass ionomer sealants.

  11. Characterization of the biological effect of fish fibrin glue in experiments on rats: Immunological and coagulation studies

    PubMed Central

    Laidmäe, Ivo; Salum, Tiit; Sawyer, Evelyn S.; Janmey, Paul A.; Uibo, Raivo

    2011-01-01

    Fibrin glues (FG) of human or bovine origin are widely used for haemostasis and wound healing. In addition FGs are studied in many biomedical areas like cell therapy or tissue engineering. As any mammalian plasma products FG-s pose risk of transmission of bacteria, viruses, or prions and may compromise patient homeostasis. In this study, we examined coagulation parameters and immunological status of rats treated with salmon-derived FG. We evaluated the changes in thrombin time, prothrombin activity, and presence of antibodies on 46 Wistar rats. This study shows that salmon-derived FG, injected intraperitoneally, does not cause coagulation disturbances in the peripheral blood. After a first challenge with salmon-derived FG there were low but detectable amounts of antibodies revealed by ELISA and immunoblot. After a second administration there was substantial elevation of antibodies to FG components and other copurifying plasma proteins. Antibody reactivity to human Factor Va, revealed in three animals, was not associated with FG application. Taken together, blood immunological and coagulation parameters support the suitability of salmon-derived FG in the development of fibrin sealants for medical use. PMID:19484773

  12. Chitosan whiskers from shrimp shells incorporated into dimethacrylate-based dental resin sealant.

    PubMed

    Mahapoka, Ekamon; Arirachakaran, Pratanporn; Watthanaphanit, Anyarat; Rujiravanit, Ratana; Poolthong, Suchit

    2012-01-01

    A resin-based sealant containing chitosan whiskers was developed for use as a pit and fissure sealer. Chitosan whiskers were synthesized and then characterized using Fourier transform infrared spectrometry and transmission electron microscopy. The whiskers were next incorporated into dimethacrylate monomer at various ratios by weight and subsequently analyzed for their antimicrobial and physical properties. The dimethacrylate-based sealant containing chitosan whiskers had a greater antimicrobial activity than control sealant and they were comparable with antimicrobial commercial resin sealants. The inclusion of the whiskers did not reduce the curing depth or degree of double bond conversion and the reduction in hardness was minimal. In conclusion, a resin-based sealant containing chitosan whiskers can be considered an effective antimicrobial pit and fissure sealant.

  13. Lidocaine Transdermal Patch

    MedlinePlus

    Lidocaine patches are used to relieve the pain of post-herpetic neuralgia (PHN; the burning, stabbing pains, ... for months or years after a shingles infection). Lidocaine is in a class of medications called local ...

  14. DyninstAPI Patches

    SciTech Connect

    LeGendre, M.

    2012-04-01

    We are seeking a code review of patches against DyninstAPI 8.0. DyninstAPI is an open source binary instrumentation library from the University of Wisconsin and University of Maryland. Our patches port DyninstAPI to the BlueGene/P and BlueGene/Q systems, as well as fix DyninstAPI bugs and implement minor new features in DyninstAPI.

  15. Identification of VLDLR as a novel endothelial cell receptor for fibrin that modulates fibrin-dependent transendothelial migration of leukocytes.

    PubMed

    Yakovlev, Sergiy; Mikhailenko, Irina; Cao, Chunzhang; Zhang, Li; Strickland, Dudley K; Medved, Leonid

    2012-01-12

    While testing the effect of the (β15-66)(2) fragment, which mimics a pair of fibrin βN-domains, on the morphology of endothelial cells, we found that this fragment induces redistribution of vascular endothelial-cadherin in a process that is inhibited by the receptor-associated protein (RAP). Based on this finding, we hypothesized that fibrin may interact with members of RAP-dependent low-density lipoprotein (LDL) receptor family. To test this hypothesis, we examined the interaction of (β15-66)(2), fibrin, and several fibrin-derived fragments with 2 members of this family by ELISA and surface plasmon resonance. The experiments showed that very LDL (VLDL) receptor (VLDLR) interacts with high affinity with fibrin through its βN-domains, and this interaction is inhibited by RAP and (β15-66)(2). Furthermore, RAP inhibited transendothelial migration of neutrophils induced by fibrin-derived NDSK-II fragment containing βN-domains, suggesting the involvement of VLDLR in fibrin-dependent leukocyte transmigration. Our experiments with VLDLR-deficient mice confirmed this suggestion by showing that, in contrast to wild-type mice, fibrin-dependent leukocyte transmigration does not occur in such mice. Altogether, the present study identified VLDLR as a novel endothelial cell receptor for fibrin that promotes fibrin-dependent leukocyte transmigration and thereby inflammation. Establishing the molecular mechanism underlying this interaction may result in the development of novel inhibitors of fibrin-dependent inflammation.

  16. Toxicity of coal-tar and asphalt sealants to eastern newts, Notophthalmus viridescens.

    PubMed

    Bommarito, Thomas; Sparling, Donald W; Halbrook, Richard S

    2010-09-01

    Between 1970 and 2000 the concentration of total polycyclic aromatic hydrocarbons (TPAH) in several lakes across the country increased whereas those of other persistent organic pollutants (POPs) tended to remain stable or declined. Urbanized watersheds experienced greater rises in TPAH concentration compared to non-urban lakes. Sources for urban PAHs include industrial wastes, vehicular exhausts and oil leaks and sealants from pavement surfaces. Both coal-tar and asphalt sealants are used to protect surfaces but runoff from surfaces coated with coal-tar can have mean concentrations of 3500 mg TPAHs kg(-1), much higher than runoff from asphalt-sealed or cement surfaces. Unaltered parent compounds of PAHs can have many lethal and sublethal toxic effects, but oxidation and UV radiation can alter the toxicity of these compounds, sometimes creating degradates that are many times more toxic than parent compounds. The purposes of this study were to determine if coal-tar sealants can be toxic to adult eastern newts (Notophthalmus viridescens) and to compare the toxicity of coal-tar sealant to that of asphalt sealant. Newts were exposed to sediments containing dried sealants ranging from 0 mg kg(-1) to 1500 mg kg(-1) under simultaneous exposure to UV radiation and visible light to determine concentration/response relationships. No significant mortality occurred with any treatment. Significant effects due to sealants included decreased righting ability and diminished liver enzyme activities. Coal-tar sealant was more effective in inducing these changes than was asphalt sealant.

  17. Development of 400 F sealants for flat plate solar collector construction and installation

    NASA Astrophysics Data System (ADS)

    Morris, L.; Schubert, R. J.

    1980-03-01

    Twenty candidate sealants representing ten different polymer types were evaluated as potential solar collector sealants. Polymer types tested included epichlorohydrin rubber, EPDM rubber, silicone, polysulfide, acrylate rubber, and a fluoroelastomer. Initial screening of sealants consisted of measuring high temperature stability and adhesion retention. Several sealant compositions exhibited satisfactory performance in these tests and were selected for further evaluation. These materials were based on an EPDM rubber, a Viton fluoroelastomer, and silicone polymers. Further testing of these candidate materials included determination of adhesion retention under uv/water/heat conditions, fogging temperature, low temperature flexibility, and physical properties. Four silicone-based materials appeared to be suitable candidates for sealing solar collectors.

  18. Ducts Sealing Using Injected Spray Sealant, Raleigh, North Carolina (Fact Sheet)

    SciTech Connect

    Not Available

    2014-03-01

    In multifamily and attached buildings, traditional duct sealing methods are often impractical or costly and disruptive because of the difficulty in accessing leakage sites. In this project, two retrofit duct sealing techniques - manually-applied sealants and injecting a spray sealant, were implemented in several low-rise multi-unit buildings. An analysis on the cost and performance of the two methods are presented. Each method was used in twenty housing units: approximately half of each group of units are single story and the remainder two-story. Results show that duct leakage to the outside was reduced by an average of 59% through the use of manual methods, and by 90% in the units where the injected spray sealant was used. It was found that 73% of the leakage reduction in homes that were treated with injected spray sealant was attributable to the manual sealing done at boots, returns and the air handler. The cost of manually-applying sealant ranged from $275 to $511 per unit and for the injected spray sealant the cost was $700 per unit. Modeling suggests a simple payback of 2.2 years for manual sealing and 4.7 years for the injected spray sealant system. Utility bills were collected for one year before and after the retrofits. Utility bill analysis shows 14% and 16% energy savings using injected spray sealant system and hand sealing procedure respectively in heating season whereas in cooling season, energy savings using injected spray sealant system and hand sealing were both 16%.

  19. The calcification of fibrin in vitro

    NASA Astrophysics Data System (ADS)

    Koutsopoulos, S.; Dalas, E.

    2000-06-01

    In the present work we employed fibrin in order to assess its capability to induce biological mineralization. Fibrin is a very important factor in the blood-clotting system. Structurally, fibrin is an ordered organic matrix which has a periodic structure that repeats every 230 Å. Hydroxyapatite, HAP and octacalcium phosphate (OCP) are the most interesting calcium phosphate salts. Hydroxyapatite is thermodynamically the most stable calcium phosphate which is mostly used as a model compound for the study of biological-calcification processes. On the other hand, octacalcium phosphate has been proposed as a precursor of hydroxyapatite whose formation is favoured kinetically in solutions supersaturated to both salts. The kinetics of crystallization of HAP and OCP on fibrin were studied using the constant composition technique. The onset of HAP crystallization started immediately after introducing the substrate in the supersaturated solution. Unlike HAP crystallization induction periods were observed before the appearance of OCP precipitate in a solution supersaturated with respect to both HAP and OCP. Using nucleation rate equations derived from the classical homogeneous nucleation theory, interfacial energies and the size of the critical nucleus for both HAP and OCP were calculated. Phosphate was taken up extensively by the biological molecule studied. The dependence of adsorption upon ionic strength and pH of the medium suggests an appreciable contribution of electrostatic forces. Controversially calcium ions did not exhibit any detectable adsorption from solutions containing calcium dichloride at concentrations ranging from 1×10 -4 to 5×10 -3 M in 0.15 M NaCl supporting electrolyte, 37°C, pH=7.4. From the results above it follows that formation of HAP on fibrin may be initiated via adsorption of inorganic phosphate on the biological substrate.

  20. Studies of new perfluoroether elastomeric sealants. [for aircraft fuel tanks

    NASA Technical Reports Server (NTRS)

    Basiulis, D. I.; Salisbury, D. P.

    1981-01-01

    Channel and filleting sealants were developed successfully from cyano and diamidoxime terminated perfluoro alkylene ether prepolymers. The prepolymers were polymerized, formulated and tested. The polymers and/or formulations therefrom were evaluated as to their physical, mechanical and chemical properties (i.e., specific gravity, hardness, nonvolatile content, corrosion resistance, stress corrosion, pressure rupture resistance, low temperature flexibility, gap sealing efficiency, tensile strength and elongation, dynamic mechanical behavior, compression set, fuel resistance, thermal properties and processability). Other applications of the formulated polymrs and incorporation of the basic prepolymers into other polymeric systems were investigated. A cyano terminated perfluoro alkylene oxide triazine was formulated and partially evaluated. The channel sealant in its present formulation has excellent pressure rupture resistance and surpasses present MIL specifications before and after fuel and heat aging.

  1. Cross Linking and Degradation Mechanisms in Model Sealant Candidates

    NASA Technical Reports Server (NTRS)

    Paciorek, K. L.; Kaufman, J.; Ito, T. I.; Nakahara, J. H.; Kratzer, R. H.

    1977-01-01

    Model compounds were investigated as to which type of heterocyclic ring is the most advantageous for curing sealants based on perfluoroalkylether chains. The relative thermal, thermal oxidative, hydrolytic, and fuel stability of potential crosslinks were determined. Specifically substituted materials were synthesized and evaluation of their stabilities in air, inert atmosphere, water, and Jet-A fuel at 235 and 325 C was made. Three heterocyclic ring systems were considered, namely, triazine, 1,2,4- and 1,3,4-oxadiazoles.

  2. Cost analysis of pulmonary lobectomy procedure: comparison of stapler versus precision dissection and sealant

    PubMed Central

    Droghetti, Andrea; Marulli, Giuseppe; Vannucci, Jacopo; Giovanardi, Michele; Bottoli, Maria Caterina; Ragusa, Mark; Muriana, Giovanni

    2017-01-01

    Objective We aimed to evaluate the direct costs of pulmonary lobectomy hospitalization, comparing surgical techniques for the division of interlobar fissures: stapler (ST) versus electrocautery and hemostatic sealant patch (ES). Methods The cost comparison analysis was based on the clinical pathway and drawn up by collecting the information available from the Thoracic Surgery Division medical team at Mantova Hospital. Direct resource consumption was derived from a previous randomized controlled trial including 40 patients. Use and maintenance of technology, equipment and operating room; administrative plus general costs; and 30-day use of postsurgery hospital resources were considered. The analysis was conducted from the hospital perspective. Results On the average, a patient submitted to pulmonary lobectomy costs €9,744.29. This sum could vary from €9,027 (using ES) to €10,460 (using ST). The overall lower incidence (50% vs 95%, P=0.0001) and duration of air leakage (1.7 days vs 4.5 days, P=0.0001) in the ES group significantly affects the mean time of hospital stay (11.0 days vs 14.3 days) and costs. Cost saving in the ES group was also driven by the lower incidence of complications. The main key cost driver was staff employment (42%), then consumables (34%) and operating room costs (12%). Conclusion There is an overall saving of around €1,432.90 when using ES patch for each pulmonary lobectomy. Among patients undergoing this surgical procedure, ES can significantly reduce air leakage incidence and duration, as well as decrease hospitalization rates. However, further multicenter research should be developed considering different clinical and managerial settings.

  3. Compliant sealants for solid oxide fuel cells and other ceramics

    DOEpatents

    Bloom, I.D.; Ley, K.L.

    1995-09-26

    A glass or glass-ceramic sealant is described for a SOFC having a coefficient of thermal expansion in the range of from about 8 to about 13{times}10{sup {minus}6}/C and a viscosity of at least 10{sup 3}Pa-s at cell operating temperature. The sealant has a composition of SrO present in the range of from about 5 to about 60 mole percent, La{sub 2}O{sub 3} present in the range of from 0 to about 45 mole percent, Al{sub 2}O{sub 3} present in the range from 0 to about 15 mole percent, B{sub 2}O{sub 3} present in the range of from about 15 mole percent to about 80 mole percent, and SiO{sub 2} present in the range of from 0 to about 40 mole percent, wherein the material is a viscous fluid at cell operating temperatures of from about 600 C to about 1000 C. The sealant may also be compounds of CaO present in the range of from 0 to about 35 mole percent, Al{sub 2}O{sub 3} present in the range from 0 to about 15 mole percent, B{sub 2}O{sub 3} present in the range of from about 35 mole percent to about 85 mole percent, and SiO{sub 2} present in the range of from 0 to about 30 mole percent. 2 figs.

  4. Compliant sealants for solid oxide fuel cells and other ceramics

    DOEpatents

    Bloom, Ira D.; Ley, Kevin L.

    1995-01-01

    A glass or glass-ceramic sealant for a SOFC having a coefficient of thermal expansion in the range of from about 8 to about 13.times.10.sup.-6 /.degree.C. and a viscosity of at least 10.sup.3 Pa-s at cell operating temperature. The sealant has a composition of SrO present in the range of from about 5 to about 60 mole percent, La.sub.2 O.sub.3 present in the range of from 0 to about 45 mole percent, Al.sub.2 O.sub.3 present in the range from 0 to about 15 mole percent, B.sub.2 O.sub.3 present in the range of from about 15 mole percent to about 80 mole percent, and SiO.sub.2 present in the range of from 0 to about 40 mole percent, wherein the material is a viscous fluid at cell operating temperatures of from about 600.degree. C. to about 1000.degree. C. The sealant may also be compounds of CaO present in the range of from 0 to about 35 mole percent, Al.sub.2 O.sub.3 present in the range from 0 to about 15 mole percent, B.sub.2 O.sub.3 present in the range of from about 35 mole percent to about 85 mole percent, and SiO.sub.2 present in the range of from 0 to about 30 mole percent.

  5. An accelerated exposure and testing apparatus for building joint sealants

    NASA Astrophysics Data System (ADS)

    White, C. C.; Hunston, D. L.; Tan, K. T.; Hettenhouser, J.; Garver, J. D.

    2013-09-01

    The design, fabrication, and implementation of a computer-controlled exposure and testing apparatus for building joint sealants are described in this paper. This apparatus is unique in its ability to independently control and monitor temperature, relative humidity, ultraviolet (UV) radiation, and mechanical deformation. Each of these environmental factors can be controlled precisely over a wide range of conditions during periods of a month or more. Moreover, as controlled mechanical deformations can be generated, in situ mechanical characterization tests can be performed without removing specimens from the chamber. Temperature and humidity were controlled during our experiments via a precision temperature regulator and proportional mixing of dry and moisture-saturated air; while highly uniform UV radiation was attained by attaching the chamber to an integrating sphere-based radiation source. A computer-controlled stepper motor and a transmission system were used to provide precise movement control. The reliability and effectiveness of the apparatus were demonstrated on a model sealant material. The results clearly show that this apparatus provides an excellent platform to study the long-term durability of building joint sealants.

  6. Preparation of hybrid scaffold from fibrin and biodegradable polymer fiber.

    PubMed

    Hokugo, Akishige; Takamoto, Tomoaki; Tabata, Yasuhiko

    2006-01-01

    A biodegradable hybrid scaffold was prepared from fibrin and poly(glycolic acid) (PGA) fiber. Mixed fibrinogen and thrombin solution homogeneously dispersed in the presence of various amounts (0, 1.5, 3.0, and 6.0mg) of PGA fiber was freeze-dried to obtain fibrin sponges with or without PGA fiber incorporation. By scanning electron microscopy observation, the fibrin sponges had an interconnected pore structure, irrespective of the amount of PGA fiber incorporated. PGA fiber incorporation enabled the fibrin sponges to significantly enhance their compression strength. In vitro cell culture studies revealed that the number of L929 fibroblasts initially attached was significantly larger for any fibrin sponge with PGA fiber incorporation than for the fibrin sponge without PGA fiber. The shrinkage of sponges after cell seeding was suppressed by fiber incorporation. It is possible that the shrinkage suppression of sponges maintains their intraspace, resulting in the superior cell attachment of a sponge with PGA fiber incorporation. After subcutaneous implantation into the backs of mice, the residual volume of a fibrin sponge with PGA fiber incorporation was significant compared with that of a fibrin sponge without PGA fiber. Larger number of cells infiltrated deep inside the fibrin sponges with PGA fiber incorporation implanted subcutaneously. It is concluded that the fibrin sponge reinforced by fiber incorporation is a promising three-dimensional scaffold of cells for tissue engineering.

  7. Effect of a surface sealant on the color stability of composite resins after immersion in staining solution.

    PubMed

    Pedroso, Lauana Borges; Barreto, Luma Franciélle Cabreira; Miotti, Leonardo Lamberti; Nicoloso, Gabriel Ferreira; Durand, Leticia Brandão

    2016-01-01

    This study evaluated the influence of surface sealants on the color stability of 2 different composite resins after immersion in coffee. Four groups were created (n = 10): microhybrid composite, microhybrid with surface sealant, nanofilled composite, and nanofilled composite with surface sealant. Half of the specimens of each group were immersed in distilled water and half were immersed in coffee for 48 hours. Color was measured before and after immersion. Groups with surface sealants presented less color variation when compared with the groups without surface sealants. The nanofilled resin specimens presented the greatest color variation within the groups without sealant. The surface sealant positively influenced the color stability of composite resin specimens immersed in coffee. When surface sealant was not applied, the microhybrid specimens had better color stability than the nanofilled.

  8. Monitoring of sound and carious surfaces under sealants over 44 months.

    PubMed

    Fontana, M; Platt, J A; Eckert, G J; González-Cabezas, C; Yoder, K; Zero, D T; Ando, M; Soto-Rojas, A E; Peters, M C

    2014-11-01

    Although there is strong evidence for the effectiveness of sealants, one major barrier in sealant utilization is the concern of sealing over active caries lesions. This study evaluated detection and monitoring of caries lesions through a clear sealant over 44 mo. Sixty-four 7- to 10-year-old children with at least 2 permanent molars with International Caries Detection and Assessment System (ICDAS) scores 0-4 (and caries less than halfway through the dentin, radiographically) were examined with ICDAS, DIAGNOdent, and quantitative light-induced fluorescence (QLF) before sealant placement and 1, 12, 24, and 44 mo (except QLF) after. Bitewing radiographs were taken yearly. DIAGNOdent and QLF were able to distinguish between baseline ICDAS before and after sealant placement. There was no significant evidence of ICDAS progression at 12 mo, but there was small evidence of minor increases at 24 and 44 mo (14% and 14%, respectively) with only 2% ICDAS ≥ 5. Additionally, there was little evidence of radiographic progression (at 12 mo = 1%, 24 mo = 3%, and 44 mo = 9%). Sealant retention rates were excellent at 12 mo = 89%, 24 mo = 78%, and 44 mo = 70%. The small risk of sealant repair increased significantly as baseline ICDAS, DIAGNOdent, and QLF values increased. However, regardless of lesion severity, sealants were 100% effective at 12 mo and 98% effective over 44 mo in managing occlusal surfaces at ICDAS 0-4 (i.e., only 4 of 228 teeth progressed to ICDAS ≥ 5 associated with sealants in need of repair and none to halfway or more through the dentin, radiographically). This study suggests that occlusal surfaces without frank cavitation (ICDAS 0-4) that are sealed with a clear sealant can be monitored with ICDAS, QLF, or DIAGNOdent, which may aid in predicting the need for sealant repair.

  9. Sperm Patch-Clamp

    PubMed Central

    Lishko, Polina; Clapham, David E.; Navarro, Betsy; Kirichok, Yuriy

    2014-01-01

    Sperm intracellular pH and calcium concentration ([Ca2+]i) are two central factors that control sperm activity within the female reproductive tract. As such, the ion channels of the sperm plasma membrane that alter intracellular sperm [Ca2+] and pH play important roles in sperm physiology and the process of fertilization. Indeed, sperm ion channels regulate sperm motility, control sperm chemotaxis toward the egg in some species, and may trigger the acrosome reaction. Until recently, our understanding of these important molecules was rudimentary due to the inability to patch-clamp spermatozoa and directly record the activity of these ion channels under voltage clamp. Recently, we overcame this technical barrier and developed a method for reproducible application of the patch-clamp technique to mouse and human spermatozoa. This chapter covers important aspects of application of the patch-clamp technique to spermatozoa, such as selection of the electrophysiological equipment, isolation of spermatozoa for patch-clamp experiments, formation of the gigaohm seal with spermatozoa, and transition into the whole-cell mode of recording. We also discuss potential pitfalls in application of the patch-clamp technique to flagellar ion channels. PMID:23522465

  10. 40 CFR 63.6008 - How do I demonstrate continuous compliance with the emission limitations for puncture sealant...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... compliance with the emission limitations for puncture sealant application affected sources? 63.6008 Section... Puncture Sealant Application Affected Sources § 63.6008 How do I demonstrate continuous compliance with the emission limitations for puncture sealant application affected sources? (a) You must demonstrate...

  11. 40 CFR 63.5988 - What emission limitations must I meet for puncture sealant application affected sources?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... for puncture sealant application affected sources? 63.5988 Section 63.5988 Protection of Environment... Tire Manufacturing Emission Limitations for Puncture Sealant Application Affected Sources § 63.5988 What emission limitations must I meet for puncture sealant application affected sources? (a) You...

  12. 40 CFR 63.6002 - How do I demonstrate initial compliance with the emission limits for puncture sealant application...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... with the emission limits for puncture sealant application affected sources? 63.6002 Section 63.6002... Sealant Application Affected Sources § 63.6002 How do I demonstrate initial compliance with the emission limits for puncture sealant application affected sources? (a) You must demonstrate initial...

  13. 40 CFR 63.5988 - What emission limitations must I meet for puncture sealant application affected sources?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... for puncture sealant application affected sources? 63.5988 Section 63.5988 Protection of Environment... Tire Manufacturing Emission Limitations for Puncture Sealant Application Affected Sources § 63.5988 What emission limitations must I meet for puncture sealant application affected sources? (a) You...

  14. 40 CFR 63.5989 - What are my alternatives for meeting the emission limitations for puncture sealant application...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the emission limitations for puncture sealant application affected sources? 63.5989 Section 63.5989... Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limitations for Puncture Sealant Application... sealant application affected sources? You must use one of the compliance alternatives in paragraphs...

  15. 40 CFR 63.6008 - How do I demonstrate continuous compliance with the emission limitations for puncture sealant...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... compliance with the emission limitations for puncture sealant application affected sources? 63.6008 Section... Puncture Sealant Application Affected Sources § 63.6008 How do I demonstrate continuous compliance with the emission limitations for puncture sealant application affected sources? (a) You must demonstrate...

  16. 40 CFR 63.6002 - How do I demonstrate initial compliance with the emission limits for puncture sealant application...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... with the emission limits for puncture sealant application affected sources? 63.6002 Section 63.6002... Sealant Application Affected Sources § 63.6002 How do I demonstrate initial compliance with the emission limits for puncture sealant application affected sources? (a) You must demonstrate initial...

  17. 40 CFR 63.5989 - What are my alternatives for meeting the emission limitations for puncture sealant application...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the emission limitations for puncture sealant application affected sources? 63.5989 Section 63.5989... Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limitations for Puncture Sealant Application... sealant application affected sources? You must use one of the compliance alternatives in paragraphs...

  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. CAUSES OF POOR SEALANT PERFORMANCE IN SOIL-GAS- RESISTANT FOUNDATIONS

    EPA Science Inventory

    The paper discusses causes of poor sealant performance in soil-gas-resistant foundations. ealants for radon-resistant foundation construction must seal the gap between concrete sections. odern sealants have such low permeability that seal performance depends only on the permeabil...

  20. 40 CFR Table 3 to Subpart Xxxx of... - Emission Limits for Puncture Sealant Application Affected Sources

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... puncture sealant application spray booth Reduce spray booth HAP (measured as VOC) emissions by at least 95... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Emission Limits for Puncture Sealant... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

  1. 40 CFR Table 3 to Subpart Xxxx of... - Emission Limits for Puncture Sealant Application Affected Sources

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... puncture sealant application spray booth Reduce spray booth HAP (measured as VOC) emissions by at least 95... 40 Protection of Environment 13 2013-07-01 2012-07-01 true Emission Limits for Puncture Sealant... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

  2. 40 CFR Table 3 to Subpart Xxxx of... - Emission Limits for Puncture Sealant Application Affected Sources

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... puncture sealant application spray booth Reduce spray booth HAP (measured as VOC) emissions by at least 95... 40 Protection of Environment 13 2014-07-01 2014-07-01 false Emission Limits for Puncture Sealant... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

  3. Current Status of Hemostatic Agents and Sealants in Urologic Surgical Practice

    PubMed Central

    Kommu, Sashi S; McArthur, Robert; Emara, Amr M; Reddy, Utsav D; Anderson, Christopher J; Barber, Neil J; Persad, Raj A; Eden, Christopher G

    2015-01-01

    There has been a recent and near exponential increase in the use of hemostatic agents and sealants to supplement the rapidly evolving methods in the surgical management of urologic patients. This article reviews the use of hemostatic agents and sealants in current urologic practice. PMID:26543429

  4. First Permanent Molar Restoration Differences between Those with or without Dental Sealants.

    ERIC Educational Resources Information Center

    Kuthy, Raymond A.; And Others

    1990-01-01

    The study examined differences in the number of restorations in permanent, posterior teeth for those children receiving dental sealants with cost sharing when compared to children who do not receive sealants. Results indicated a 51 percent reduction in restoration rates for each quadrant sealed. Findings have implications for cost savings and…

  5. Biodegradable-Polymer-Blend-Based Surgical Sealant with Body-Temperature-Mediated Adhesion.

    PubMed

    Behrens, Adam M; Lee, Nora G; Casey, Brendan J; Srinivasan, Priya; Sikorski, Michael J; Daristotle, John L; Sandler, Anthony D; Kofinas, Peter

    2015-12-22

    The development of practical and efficient surgical sealants has the propensity to improve operational outcomes. A biodegradable polymer blend is fabricated as a nonwoven fiber mat in situ. After direct deposition onto the tissue of interest, the material transitions from a fiber mat to a film. This transition promotes polymer-substrate interfacial interactions leading to improved adhesion and surgical sealant performance.

  6. Qualification, Demonstration & Validation of Compliant Removers for Aircraft Sealants and Specialty Coatings ESTCP WP-0621

    DTIC Science & Technology

    2010-06-01

    materials/ methods to approach sealant removal tasks consistently and effectively, depending upon situation. BUSINESS SENSITIVE 6 TECHNICAL APROACH ...Dem/Val 3 at New River MCAS - V-22 Osprey TECHNICAL APROACH BUSINESS SENSITIVE 5 TECHNICAL APROACH “Toolbox” Approach: Provide end users with...Demonstration Tests (UDRI) - Testing Protocols Parameter Test Test Method Sealant Removal Force Measuring Unit UDRI Proprietary Substrate Damage Potential

  7. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... clotting within a blood vessel) or in the differential diagnosis between disseminated intravascular coagulation and primary fibrinolysis (dissolution of the fibrin in a blood clot). (b) Classification. Class...

  8. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... clotting within a blood vessel) or in the differential diagnosis between disseminated intravascular coagulation and primary fibrinolysis (dissolution of the fibrin in a blood clot). (b) Classification. Class...

  9. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... clotting within a blood vessel) or in the differential diagnosis between disseminated intravascular coagulation and primary fibrinolysis (dissolution of the fibrin in a blood clot). (b) Classification. Class...

  10. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... clotting within a blood vessel) or in the differential diagnosis between disseminated intravascular coagulation and primary fibrinolysis (dissolution of the fibrin in a blood clot). (b) Classification. Class...

  11. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... clotting within a blood vessel) or in the differential diagnosis between disseminated intravascular coagulation and primary fibrinolysis (dissolution of the fibrin in a blood clot). (b) Classification. Class...

  12. 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.

  13. Fissure sealant materials: Wear resistance of flowable composite resins

    PubMed Central

    Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

    2016-01-01

    Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm2 and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm2of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics. PMID:27651887

  14. Fissure sealant materials: Wear resistance of flowable composite resins.

    PubMed

    Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

    2016-01-01

    Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm(2) and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm(2)of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics.

  15. Effect of Adhesive Application on Sealant Success: A Clinical Study of Fifth and Seventh Generation Adhesive Systems

    PubMed Central

    Tandon, Vaibhav; Tangade, Pradeep Shankar; Tirth, Amit; Pal, Sumit Kumar; Lingesha, Chaitra Telgi; Arora, Vikram; Yadav, Vipul

    2015-01-01

    Objectives: The aim of the study was to compare the effect of fifth and seventh generation bonding agent on sealant success. Materials and Methods: Sixty-four school children aged six to nine years received sealants in four permanent molars in a split mouth design, such that each patient received sealant in the first permanent molar with fifth generation bonding agent in one arch and seventh generation bonding agent in the other arch; contra-lateral molars were sealed with sealant alone. The evaluation was carried out at baseline, three months, six months and 12 months, according to the criteria by Feigal et al, in 2000. Chi- square test was used to analyze data at P<0.05 level of significance. Results: Statistically significant differences were found for sealant retention between fifth generation and sealant group, and fifth generation and seventh generation groups; whereas, no significant difference was found for sealant retention between seventh generation and sealant group at three, six and 12 months. Conclusion: As separate etch and rinse steps are not required for seventh generation bonding agents, and almost similar results were obtained for both sealant and seventh generation groups, it can be concluded that application of sealant along with a seventh generation bonding agent may enhance sealant success and can be used for caries prevention in preventive programs. PMID:27252754

  16. Bonding Agents in Pit and Fissure Sealants: A Review

    PubMed Central

    Das, Usha Mohan; G, Suma

    2009-01-01

    Dental adhesive systems used for bonding dental resins to enamel and dentin have evolved through several "generations," with changes in chemistry, mechanism, number of bottles, application technique, and clinical effectiveness. The trend in the latest generation of dental bonding systems is to reduce the number of components and clinical placement steps. The introduction of i bond, a single-bottle dental adhesive system, is the latest of the new generation materials, and combines etchant, adhesive, and desensitizer in one component. This paper describes different dentin bonding agents, its evolution, mechanism of action and different commercially available dentin bonding agents and their role in the retention of pit and fissure sealant. PMID:25206115

  17. Effect of an Antibacterial Monomer on the Antibacterial Activity of a Pit-and-Fissure Sealant

    PubMed Central

    Dong, Yan; Zhang, Ling; Sun, Xiang; Liu, Zhengya; Guo, Huihui; Huang, Li; Chen, Jihua

    2016-01-01

    Resin-based pit-and-fissure sealants are often used to form a barrier on the occlusal surface of molars to treat caries lesions; however, bacteria can remain in the pit and fissures without detection, increasing the risk of secondary caries. Sealants with antimicrobial properties or microbial repellent actions might be advantageous. The aim of this study was to assess the inhibitory effect of a 2-methacryloxylethyl dodecyl methyl ammonium bromide (MAE-DB)-incorporated sealant against Streptococcus mutans. MAE-DB (4% wt) was incorporated into a commercially available sealant, Eco-S resin-based pit-and-fissure sealant (Vericom Co., Ltd., Korea); a sealant without MAE-DB served as a negative control, and Clinpro™ Sealant (3M™ ESPE™), a fluoride-releasing resin, was used as a commercial control. The effects of the cured sealants and their eluents on the growth of S. mutans were determined according to colony-forming unit counts and metabolic tests. The effects of the cured sealants on the adherence and membrane integrity of S. mutans were investigated using confocal laser-scanning microscopy (CLSM) in conjunction with fluorescent indicators. Compared with the negative control and commercial control, the cured MAE-DB-incorporated pit-and-fissure sealant exhibited a significant inhibitory effect on the growth of S. mutans (P < 0.05), whereas the eluents did not show any detectable antibacterial activity. The commercial control also showed no detectable bactericidal activity. Moreover, the aged experimental material retained its property of contact inhibition of biofilm formation. The fluorescence analysis of CLSM images demonstrated that the cured MAE-DB-incorporated sealant could hamper the adherence of S. mutans and exert a detrimental effect on bacterial membrane integrity. The incorporation of MAE-DB can render a pit-and-fissure sealant with contact antibacterial activity after polymerization via influencing the growth, adherence, and membrane integrity of S

  18. Contaminating fibrin in CPD-blood: solubility in plasma and distribution in blood components following separation

    SciTech Connect

    Skjonsberg, O.H.; Kierulf, P.; Gravem, K.; Fagerhol, M.K.; Godal, H.C.

    1986-01-01

    In order to estimate the solubility of contaminating fibrin in CPD-blood, thrombin induced fibrin polymerzation in CPD-plasma was examined by light scattering and fibrinopeptide A (FPA) determinations. In addition, I-125 fibrin monomer enriched CPD-blood was used to investigate fibrin monomer retention in blood bags and transfusion filters (170 microns) and fibrin distribution in blood components derived from CPD-blood. Initial fibrin polymerization in CPD-blood occurred after conversion of 15 per cent of the fibrinogen to fibrin, implying that substantial amounts of fibrin may be kept solubilized in CPD-blood bags. Only minor amounts of I-125 fibrin monomers were retained in blood bags (2.4 per cent) and in transfusion filters (2.9 per cent) after sham transfusions. After separating I-125-fibrin monomer enriched CPD-blood into its constituent components, the major part of fibrin (75.0 per cent) could be traced in the cryoprecipitate.

  19. Circulating Microparticles Alter Formation, Structure, and Properties of Fibrin Clots

    PubMed Central

    Zubairova, Laily D.; Nabiullina, Roza M.; Nagaswami, Chandrasekaran; Zuev, Yuriy F.; Mustafin, Ilshat G.; Litvinov, Rustem I.; Weisel, John W.

    2015-01-01

    Despite the importance of circulating microparticles in haemostasis and thrombosis, there is limited evidence for potential causative effects of naturally produced cell-derived microparticles on fibrin clot formation and its properties. We studied the significance of blood microparticles for fibrin formation, structure, and susceptibility to fibrinolysis by removing them from platelet-free plasma using filtration. Clots made in platelet-free and microparticle-depleted plasma samples from the same healthy donors were analyzed in parallel. Microparticles accelerate fibrin polymerisation and support formation of more compact clots that resist internal and external fibrinolysis. These variations correlate with faster thrombin generation, suggesting thrombin-mediated kinetic effects of microparticles on fibrin formation, structure, and properties. In addition, clots formed in the presence of microparticles, unlike clots from the microparticle-depleted plasma, contain 0.1–0.5-μm size granular and CD61-positive material on fibres, suggesting that platelet-derived microparticles attach to fibrin. Therefore, the blood of healthy individuals contains functional microparticles at the levels that have a procoagulant potential. They affect the structure and stability of fibrin clots indirectly through acceleration of thrombin generation and through direct physical incorporation into the fibrin network. Both mechanisms underlie a potential role of microparticles in haemostasis and thrombosis as modulators of fibrin formation, structure, and resistance to fibrinolysis. PMID:26635081

  20. Spin Glass Patch Planting

    NASA Technical Reports Server (NTRS)

    Wang, Wenlong; Mandra, Salvatore; Katzgraber, Helmut G.

    2016-01-01

    In this paper, we propose a patch planting method for creating arbitrarily large spin glass instances with known ground states. The scaling of the computational complexity of these instances with various block numbers and sizes is investigated and compared with random instances using population annealing Monte Carlo and the quantum annealing DW2X machine. The method can be useful for benchmarking tests for future generation quantum annealing machines, classical and quantum mechanical optimization algorithms.

  1. Research and analysis of patch shape on microstrip patch antenna

    NASA Astrophysics Data System (ADS)

    Ji, Ai-guo; Wang, Peng

    2017-01-01

    The shape of the radiating patch in the microstrip patch antenna is one of the many factors that affect the performance of the microstrip antenna.In this paper, on the premise of center frequency of 2.45 GHz, rectangular, circular and triangular microstrip patch antennas are designed and simulated respectively.The simulation results of the three microstrip patch antenna are analyzed, such as feed point position, return loss and radiation patterns.The influence of the shape of the radiation patch on the impedance bandwidth, gain and directivity of microstrip antennas is discussed.The simulation results show that the comprehensive performance of rectangular microstrip patch antenna is better than the other two, the comprehensive performance of triangular microstrip patch antenna is poor.

  2. Selective removal of composite sealants with near-ultraviolet laser pulses of nanosecond duration.

    PubMed

    Louie, Tiffany M; Jones, Robert S; Sarma, Anupama V; Fried, Daniel

    2005-01-01

    It is often necessary to replace pit and fissure sealants and composite restorations. This task is complicated by the necessity for complete removal of the remaining composite to enable suitable adhesion of new composite. Previous studies have shown that 355-nm laser pulses from a frequency-tripled Nd:YAG laser can selectively remove residual composite after orthodontic bracket removal on enamel surfaces. Our objective is to determine if such laser pulses are suitable for selective removal of composite pit and fissure sealants and restorations. Optical coherence tomography is used to acquire optical cross sections of the occlusal topography nondestructively before sealant application, after sealant application, and after sealant removal. Thermocouples are used to monitor the temperature in the pulp chamber during composite removal under clinically relevant ablation rates, i.e., 30 Hz and 30 mJ/pulse. At an irradiation intensity of 1.3 J/cm2, pit and fissure sealants are completely removed without visible damage to the underlying enamel. At intensities above 1.5 J/cm2, incident laser pulses remove the resin layer while at the same time preferentially etching the surface of the enamel. Temperature excursions in the pulp chamber of extracted teeth are limited to less than 5 degrees C if air-cooling is used during the rapid removal (1 to 2 min) of sealants, water-cooling is not necessary. Selective removal of composite restorative materials is possible without damage to the underlying sound tooth structure.

  3. Toxicity of coal-tar pavement sealants and ultraviolet radiation to Ambystoma Maculatum.

    PubMed

    Bommarito, Thomas; Sparling, Donald W; Halbrook, Richard S

    2010-08-01

    Polycyclic aromatic hydrocarbons (PAHs) can affect amphibians in lethal and many sublethal ways. There are many natural and anthropogenic sources of PAHs in aquatic environments. One potentially significant source is run off from surfaces of parking lots and roads that are protected with coal tar sealants. Coal tar is 50% or more PAH by wet weight and is used in emulsions to treat these surfaces. Break down of sealants can result in contamination of nearby waters. The toxicity of PAHs can be greatly altered by simultaneous exposure to ultraviolet radiation. This study exposes larvae of the spotted salamander (Ambystoma maculatum) to determine if coal tar sealant can have negative effects on aquatic amphibians and if coal tar toxicity is influenced by ultraviolet radiation. Spotted salamanders were exposed to 0, 60, 280 and 1500 mg coal tar sealant/kg sediment for 28 days. Half of the animals were exposed to conventional fluorescent lighting only and half were exposed to fluorescent lighting plus ultraviolet radiation. No significant mortality occurred during the experiment. Exposure to sealants resulted in slower rates of growth, and diminished ability to swim in a dose-dependent fashion. Exposure to ultraviolet radiation affected the frequencies of leukocytes and increased the incidence of micronucleated erythrocytes. There was an interactive effect of sealant and radiation on swimming behavior. We conclude that coal-tar sealant and ultraviolet radiation increased sublethal effects in salamanders, and may be a risk to salamanders under field conditions.

  4. Rheological characterization of human fibrin and fibrin-agarose oral mucosa substitutes generated by tissue engineering.

    PubMed

    Rodríguez, I A; López-López, M T; Oliveira, A C X; Sánchez-Quevedo, M C; Campos, A; Alaminos, M; Durán, J D G

    2012-08-01

    In regenerative medicine, the generation of biocompatible substitutes of tissues by in vitro tissue engineering must fulfil certain requirements. In the case of human oral mucosa, the rheological properties of tissues deserve special attention because of their influence in the acoustics and biomechanics of voice production. This work is devoted to the rheological characterization of substitutes of the connective tissue of the human oral mucosa. Two substitutes, composed of fibrin and fibrin-agarose, were prepared in cell culture for periods in the range 1-21 days. The time evolution of the rheological properties of both substitutes was studied by two different experimental procedures: steady-state and oscillatory measurements. The former allows the plastic behaviour of the substitutes to be characterized by estimating their yield stress; the latter is employed to quantify their viscoelastic responses by obtaining the elastic (G') and viscous (G'') moduli. The results demonstrate that both substitutes are characterized by a predominant elastic response, in which G' (order 100 Pa) is roughly one order of magnitude larger than G'' (order 10 Pa). But the most relevant insight is the stability, throughout the 21 days of culture time, of the rheological quantities in the case of fibrin-agarose, whereas the fibrin substitute shows a significant hardening. This result provides evidence that the addition to fibrin of a small amount of agarose allows the rheological stability of the oral mucosa substitute to be maintained. This feature, together with its viscoelastic similitude with native tissues, makes this biomaterial appropriate for potential use as a scaffold in regenerative therapies of human oral mucosa.

  5. Retention of resin-based filled and unfilled pit and fissure sealants: A comparative clinical study

    PubMed Central

    Reddy, V. Rajashekar; Chowdhary, Nagalakshmi; Mukunda, K. S.; Kiran, N. K.; Kavyarani, B. S.; Pradeep, M. C.

    2015-01-01

    Background and Objectives: The most caries-susceptible period of a permanent first molar tooth is the eruption phase, during which the enamel is not fully matured and it is usually difficult for the child to clean the erupting tooth surfaces. Sealing occlusal pits and fissures with resin-based pit and fissure sealants is a proven method to prevent occlusal caries. The difference in the viscosity of the sealants differs in the penetration into pit and fissures and abrasive wear resistance property due to the addition of filler particles. The present study was conducted to evaluate and compare the retention of the resin-based filled (Helioseal F, Ivoclar Vivadent) and unfilled (Clinpro, 3M ESPE) pit and fissure sealants, which is important for their effectiveness. Materials and Methods: Fifty-six children between the age group of 6 and 9 years, with all four newly erupted permanent first molars were selected. Sealants were applied randomly using split mouth design technique on permanent first molars. Evaluation of sealant retention was performed at regular intervals over 12 months, using Simonsen's criteria at 2nd, 4th, 6th, 8th, 10th and 12th month. The results were subjected to statistical analysis. Results: At the end of our study period (12th month), 53.57% showed complete retention, 37.50% showed partial retention, and 8.83% showed complete missing of resin-based filled (Helioseal F) pit and fissure sealant. And, 64.29% showed complete retention, 32.14% showed partial retention, and 3.57% showed complete missing of resin-based unfilled (Clinpro) pit and fissure sealant. This difference in retention rates between filled and unfilled pit and fissure sealants was not statistically significant. Conclusion: The difference in retention rates between Helioseal F and Clinpro was not statistically significant, but Clinpro (unfilled) sealant showed slightly higher retention rates and clinically better performance than Helioseal F (filled). PMID:25821368

  6. Reinforced composite sealants for solid oxide fuel cell applications

    NASA Astrophysics Data System (ADS)

    Gross, Sonja M.; Federmann, Dirk; Remmel, Josef; Pap, Michael

    Glass-ceramic sealants are commonly used as joining materials for planar solid oxide fuel cells stacks. Several requirements need to be fulfilled by these materials: beside of electrical insulation and appropriate thermal expansion, a good adhesion on the ceramic and metallic components of a SOFC stack is necessary to form a gas-tight joint. Even though the joining process might have been successful, failures and leaks often occur during the stack operation due to fracture of the brittle material under thermal stresses or during thermal cycling of the components. This study focusses on composite materials consisting of a glass matrix based on the system of BaO-CaO-SiO 2 and various filler materials, e.g. yttria-stabilized zirconia fibres or particles and silver particles. In order to evaluate a possible reinforcing influence of the filler material of the composite, tensile strength tests were carried out on circular butt joints. The highest strength values were found for the composite material with addition of silver particles, followed by the glass matrix itself without any filler addition and the lowest values were measured for the composite with YSZ particles. SEM investigations of cross-sections of the joints elucidated these results by the microstructure of the glass-ceramic sealants.

  7. Dystrophic heart failure blocked by membrane sealant poloxamer

    NASA Astrophysics Data System (ADS)

    Yasuda, Soichiro; Townsend, Dewayne; Michele, Daniel E.; Favre, Elizabeth G.; Day, Sharlene M.; Metzger, Joseph M.

    2005-08-01

    Dystrophin deficiency causes Duchenne muscular dystrophy (DMD) in humans, an inherited and progressive disease of striated muscle deterioration that frequently involves pronounced cardiomyopathy. Heart failure is the second leading cause of fatalities in DMD. Progress towards defining the molecular basis of disease in DMD has mostly come from studies on skeletal muscle, with comparatively little attention directed to cardiac muscle. The pathophysiological mechanisms involved in cardiac myocytes may differ significantly from skeletal myofibres; this is underscored by the presence of significant cardiac disease in patients with truncated or reduced levels of dystrophin but without skeletal muscle disease. Here we show that intact, isolated dystrophin-deficient cardiac myocytes have reduced compliance and increased susceptibility to stretch-mediated calcium overload, leading to cell contracture and death, and that application of the membrane sealant poloxamer 188 corrects these defects in vitro. In vivo administration of poloxamer 188 to dystrophic mice instantly improved ventricular geometry and blocked the development of acute cardiac failure during a dobutamine-mediated stress protocol. Once issues relating to optimal dosing and long-term effects of poloxamer 188 in humans have been resolved, chemical-based membrane sealants could represent a new therapeutic approach for preventing or reversing the progression of cardiomyopathy and heart failure in muscular dystrophy.

  8. Chemically bonded phosphate ceramic sealant formulations for oil field applications

    SciTech Connect

    Wagh, Arun S.; Jeong, Seung-Young; McDaniel, Richard

    2008-10-21

    A sealant for an oil or geothermal well capable of setting within about 3 to about 6 hours at temperatures less than about 250.degree. F. for shallow wells less than about 10,000 feet and deep wells greater than about 10,000 feet having MgO present in the range of from about 9.9 to about 14.5%, KH.sub.2PO.sub.4 present in the range of from about 29.7 to about 27.2%, class C fly ash present in the range of from about 19.8 to about 36.3%, class F fly ash present in the range of from about 19.8 to about 0%, boric acid or borax present in the range of from about 0.39 to about 1.45%, and water present in the range of from about 20.3 to about 21.86% by weight of the sealant.A method of sealing wells is disclosed as are compositions for very high temperature wells is disclosed as is a composition for treating oil field wastes.

  9. Patch Test Negative Generalized Dermatitis.

    PubMed

    Spiker, Alison; Mowad, Christen

    2016-01-01

    Allergic contact dermatitis is a common condition in dermatology. Patch testing is the criterion standard for diagnosis. However, dermatitis is not always caused by an allergen, and patch testing does not identify a culprit in every patient. Generalized dermatitis, defined as eczematous dermatitis affecting greater than 3 body sites, is often encountered in dermatology practice, especially patch test referral centers. Management for patients with generalized dermatitis who are patch test negative is challenging. The purpose of this article is to outline an approach to this challenging scenario and summarize the paucity of existing literature on patch test negative generalized dermatitis.

  10. Concentration of fibrin and presence of plasminogen affect proliferation, fibrinolytic activity, and morphology of human fibroblasts and keratinocytes in 3D fibrin constructs.

    PubMed

    Reinertsen, Erik; Skinner, Michael; Wu, Benjamin; Tawil, Bill

    2014-11-01

    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.

  11. 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.

  12. Qualification, Demonstration & Validation of Compliant Removers for Aircraft Sealants and Specialty Coatings

    DTIC Science & Technology

    2011-02-01

    10 Material Selection • Sealant Materials • PR-1422 B-2 (Polysulfide) – AMS-S-8802 • PR-1750 B-2 (Polysulfide... sealant focus • Dem/Val 1 at Hill AFB • F-16 Wing Spar/Pylons • C-130 Sloping Longeron • A- 10 Wing IML • Dem/Val 2 at FRCSE • P-3 OML...Military • Elixaire Sky Restore – Currently in use as aircraft cleaner and solvent – Efforts underway to promote as sealant remover –

  13. Adhesive strength of autologous fibrin glue.

    PubMed

    Yoshida, H; Hirozane, K; Kamiya, A

    2000-03-01

    To establish an easy and rapid method for measuring the adhesive strength of fibrin glue and to clarify the factor(s) most affecting the strength, a study was made on the effect of the concentration of plasma components on the strength of cryoprecipitate (Cryo) prepared from a subject's own autologous plasma to be used as fibrin glue. The adhesive strength of the Cryo was measured with various supporting materials instead of animal skin using a tester of tension and compression. The results were as follows: (1) the strength of Cryo applied to ground flat glass (4 cm2) was significantly greater than that applied to clear glass, clear plastic, or smooth and flat wood chips; (2) the adhesive strength of Cryo depended on the concentration of thrombin with the optimal concentration being 50 units/ml; (3) the concentration of CaCl2 did not affect the adhesive strength of Cryo; (4) the adhesive reaction was dependent on the temperature and the adhesive strength more quickly reached a steady state at 37 degrees C than at lower temperature; (5) the adhesive strength was correlated well with the total concentration of fibrinogen and fibronectin. These results indicate that the adhesive strength of Cryo can be easily and quickly evaluated using a tester and ground glass with thrombin at 50 units/ml, and that the adhesive strength of Cryo can be predicted from the total concentration of fibrinogen and fibronectin.

  14. 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.

  15. Polar Cap Patch Dynamics

    DTIC Science & Technology

    2013-04-25

    3 . Campaign periods for the 2010/2011 winter 3.1 Operation periods Ny-Ålesund 29 Nov - 13 Dec 2010 28 Dec - 10 Jan 2011 25 Jan - 8 Feb...dominated by a stable interplanetary magnetic field (IMF) B z < 0 and by an IMF B y > 0 situation. The aurora was characterized by a series of PMAFs...Svalbard Radar of two intense polar cap patch events on 6 February 2001. The interplanetary magnetic field (IMF) was dominated by a large positive By

  16. Patch antenna terahertz photodetectors

    SciTech Connect

    Palaferri, D.; Todorov, Y. Chen, Y. N.; Madeo, J.; Vasanelli, A.; Sirtori, C.; Li, L. H.; Davies, A. G.; Linfield, E. H.

    2015-04-20

    We report on the implementation of 5 THz quantum well photodetector exploiting a patch antenna cavity array. The benefit of our plasmonic architecture on the detector performance is assessed by comparing it with detectors made using the same quantum well absorbing region, but processed into a standard 45° polished facet mesa. Our results demonstrate a clear improvement in responsivity, polarization insensitivity, and background limited performance. Peak detectivities in excess of 5 × 10{sup 12} cmHz{sup 1/2}/W have been obtained, a value comparable with that of the best cryogenic cooled bolometers.

  17. Peptide-derivatized albumins that inhibit fibrin polymerization.

    PubMed

    Watson, Joseph W; Doolittle, Russell F

    2011-11-15

    Synthetic peptides patterned on sequences that appear during thrombin proteolysis of fibrinogen are known to influence fibrin formation in very different ways. A-Knob sequences (GPR-) inhibit polymerization, but B-knob sequences (GHR-) can actually enhance the process. We now report that when such peptides are attached to albumin carriers, both knob conjugates inhibit fibrin formation. In contrast, the 2-aminoethylthiol-albumin conjugate control enhances the polymerization to the same degree as albumin. The peptide AHRPam, which is known to bind exclusively to the βC holes of fibrinogen/fibrin, nullifies the inhibitory effects of the GHRPYGGGCam-albumin conjugate on fibrin polymerization, indicating that the inhibition was exclusively due to interactions with βC holes. AHRPam was much less effective in countering inhibition by the GPRPGGGGCam-albumin conjugate, suggesting that the observed effects with this conjugate involve mainly the γC holes of fibrin/fibrinogen. This study demonstrates that peptides modeled on fibrin polymerization knobs tethered to albumin retain their capacity to interact with fibrinogen/fibrin and may prove useful as inhibitors of clotting in vivo.

  18. Discriminating Neoantigenic Differences Between Fibrinogen and Fibrin Derivatives

    PubMed Central

    Plow, Edward F.; Edgington, Thomas S.

    1973-01-01

    Discrimination between the physiological cleavage fragments of fibrinogen and fibrin offers an approach to differentiation between fibrinogenolytic processes and fibrinolysis after coagulation. By use of the cleavage-associated neoantigen of fibrinogen (fg-Dneo) as a molecular marker, characteristic differences between the D regions of fibrinogen derivatives and fibrin derivatives can be demonstrated. The expression of fg-Dneo by X, Y, D:E complex, and D-fragments of fibrinogen or fibrin is shown to be quantitative and unitary. Characteristic differences between fg-Dneo sites present on fibrinogen cleavage fragments, as contrasted to fibrin cleavage fragments, are indicated by different competitive inhibition slopes, and appear to reflect differential binding affinity of selected anti-fg-Dneo antibodies for the specific molecular site. There is a linear relationship between the slope of quantitative competitive inhibition and the relative molar ratio of fibrinogen and fibrin derivatives. Identical immunochemical expressions are observed in vitro and in vivo, and support the thesis that cleavage in vivo is produced by plasmin. The differential immunochemical features of fg-Dneo expression may be the result of stable conformational and/or subtle structural differences between the D region of fibrinogen and fibrin cleavage fragments and suggest that precise changes in the D region are associated with the fibrin transition. These molecular features not only provide additional insight into the molecular immunology and structure of fibrinogen, but also appear to offer a new molecular approach to discrimination between fibrinogenolytic mechanisms as contrasted to fibrinolysis secondary to coagulation. PMID:4123931

  19. Role of plasma-rich fibrin in oral surgery

    PubMed Central

    Kumar, K. Retna; Genmorgan, K.; Abdul Rahman, S. M.; Rajan, M. Alaguvel; Kumar, T. Arul; Prasad, V. Srinivas

    2016-01-01

    Platelet-rich fibrin (PRF) is a fibrin meshwork, in which platelet cytokines, growth factors, and cells are entrapped and discharged after a period and can serve as a resorbable film. PRF is the next generation of platelet concentrates equipped to improve arrangement without biochemical blood handling; PRF is an evolution of the fibrin adhesive, which is widely used in the oral surgery. The guidelines of this innovation depend on concentrating platelets and growth factors in a plasma medium, and initiating them in a fibrin gel, keeping in mind the end goal to enhance the healing of wounds. Maxillary bone loss requires numerous regenerative techniques: as a supplement to the procedures of tissue regeneration, a platelet concentrate called PRF was tested for the 1st time in France by Dr. Choukroun. This article enriches the benefits and role of plasma-rich fibrin in oral surgery. Platelet-concentrate fibrin is an evolution of the fibrin glue, which is widely used in the oral surgery. PMID:27829743

  20. Effect of sealants of the sound absorption coefficients of acoustical friable insulating materials

    NASA Astrophysics Data System (ADS)

    Wayman, J. L.; Lory, M. K.

    1984-10-01

    Acoustical friable insulating materials (AFIM), which often in the past contained asbestos, have been used for sound control since the mid 1930's. Because of their widespread use and the ease of fiber dissemination, friable asbestos materials are considered to be the major source of asbestos fiber contamination in the indoor environment. Encapsulation of asbestos materials with a commercial sealant product is one of several methods used to control potential asbestos exposure in rooms. A sealant product that preserves most of the acoustical properties of the material is preferred in this usage. AFIM sample materials were treated with 6 types of sealants and the effects on normally incident absorption coefficients from 100 to 2500 Hz were measured using a fixed, dual-microphone technique. Penetrating type sealants were found to have a less detrimental effect on sound absorption than those of a bridging type.

  1. Patched Conic Trajectory Code

    NASA Technical Reports Server (NTRS)

    Park, Brooke Anderson; Wright, Henry

    2012-01-01

    PatCon code was developed to help mission designers run trade studies on launch and arrival times for any given planet. Initially developed in Fortran, the required inputs included launch date, arrival date, and other orbital parameters of the launch planet and arrival planets at the given dates. These parameters include the position of the planets, the eccentricity, semi-major axes, argument of periapsis, ascending node, and inclination of the planets. With these inputs, a patched conic approximation is used to determine the trajectory. The patched conic approximation divides the planetary mission into three parts: (1) the departure phase, in which the two relevant bodies are Earth and the spacecraft, and where the trajectory is a departure hyperbola with Earth at the focus; (2) the cruise phase, in which the two bodies are the Sun and the spacecraft, and where the trajectory is a transfer ellipse with the Sun at the focus; and (3) the arrival phase, in which the two bodies are the target planet and the spacecraft, where the trajectory is an arrival hyperbola with the planet as the focus.

  2. Statistics for Patch Observations

    NASA Astrophysics Data System (ADS)

    Hingee, K. L.

    2016-06-01

    In the application of remote sensing it is common to investigate processes that generate patches of material. This is especially true when using categorical land cover or land use maps. Here we view some existing tools, landscape pattern indices (LPI), as non-parametric estimators of random closed sets (RACS). This RACS framework enables LPIs to be studied rigorously. A RACS is any random process that generates a closed set, which encompasses any processes that result in binary (two-class) land cover maps. RACS theory, and methods in the underlying field of stochastic geometry, are particularly well suited to high-resolution remote sensing where objects extend across tens of pixels, and the shapes and orientations of patches are symptomatic of underlying processes. For some LPI this field already contains variance information and border correction techniques. After introducing RACS theory we discuss the core area LPI in detail. It is closely related to the spherical contact distribution leading to conditional variants, a new version of contagion, variance information and multiple border-corrected estimators. We demonstrate some of these findings on high resolution tree canopy data.

  3. Comparison of Microleakage and Penetration Depth between Hydrophilic and Hydrophobic Sealants in Primary Second Molar

    PubMed Central

    Chaugule, Vishwas B; Panse, Amey M

    2016-01-01

    Introduction Optimal pit and fissure sealing is determined by surface preparation techniques and choice of materials. The performance of pit and fissure sealant materials has been intensively investigated, yet no single product is reported as an ideal sealant. In children, moisture control during cavity preparation is always a big challenge, and hence, hydrophilic sealants have been developed. Aim To compare the microleakage and penetration depth of hydrophilic and hydrophobic sealants using acid-etching on dry and moist surfaces. Materials and methods Recently, extracted 28 2nd primary molars are assigned to two groups (hydrophobic group I; hydrophilic group II) depending on the surface condition (dry group: A1 and B1; moist group: A2 and B2) of 7 teeth in each group. Samples from group A1 and B1 are cleaned and dried with a 3-way syringe and etched with etching gel, and sealant is applied to the fissures and cured with visible light. Sample from A2 and B2 are immersed in 0.1 mL of fresh whole human saliva for 20 seconds and dried using a pellet cotton, and the same procedure is carried out. All samples are subjected to 1000 thermal cycles and sectioned to compare the depth of penetration and microleakage. Sections will be examined under light microscope and analyzed using an image analysis software (SigmaScan). Results The least microleakage was seen with hydrophilic sealant under moist surface condition, and the depth of penetration of hydrophobic sealant was found to be better than that of hydrophilic sealant in both dry and moist surface conditions. Conclusion Hydrophilic pit and fissure sealants showed higher tolerance to saliva contamination with less microleakage, but in terms of penetration ability hydrophobic sealants were found to be superior. How to cite this article Gawali PN, Chaugule VB, Panse AM. Comparison of Microleakage and Penetration Depth between Hydrophilic and Hydrophobic Sealants in Primary Second Molar. Int J Clin Pediatr Dent 2016

  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. Conversion degree, microhardness, microleakage and fluoride release of different fissure sealants.

    PubMed

    Kuşgöz, Adem; Tüzüner, Tamer; Ulker, Mustafa; Kemer, Bariş; Saray, Onur

    2010-11-01

    The purpose of this study was to determine the degree of conversion (DC), microhardness, microleakage and fluoride release of a nano-filled resin based fissure sealant (Grandio Seal, GS) and compare it with an un-filled resin based fissure sealant (Clinpro, CL) and a glass-ionomer based fissure sealant (Fuji Triage, FT). Disk shaped specimens were prepared from tested fissure sealants to determine the DC, Vicker hardness (VHN) and fluoride release (FR). The DC and VHN of each material was evaluated after 24 h. The cumulative fluoride concentrations were evaluated at 1 h, 6 h, 12 h, 1, 7, 15 and 30 days. For microleakage evaluation, fissure sealants were applied to the etched and dried enamel surfaces of sound third molar teeth according to the manufacturer's instructions (n=10). After the thermocycling and mechanical loading procedures, microleakage assessments were carried out. Data were analyzed using one-way ANOVA followed by a post hoc Tukey test, the Kruskal Wallis and Mann-Whitney U test (p<0.05). Results revealed differences regarding DC between all groups: FT (89%) > GS (55.02%) > CL (%51.10) (p<0.05). The VHN values were significantly different among all groups in the following order: GS > FT > CL (p<0.05). FT exhibited significantly higher microleakage scores compared to the CL and GS sealants (p<0.05). The FR of FT was significantly greater than CL and GS (p<0.05). Nano-filled resin based sealant can be used as an alternative to other fissure sealant materials because of its superior hardness results and feasible sealing ability.

  6. OMNEX surgical sealant in the extracorporeal repair of renal artery aneurysms.

    PubMed

    Garcia-Roig, Michael; Gorin, Michael A; Castellan, Miguel; Ciancio, Gaetano

    2011-11-01

    OMNEX (Ethicon, Inc.; Somerville, NJ) is a cyanoacrylate-based synthetic surgical sealant. To date, the use of OMNEX has only been described in a limited number of vascular surgery procedures. We present the cases of two patients who underwent successful extracorporeal renal artery aneurysm repair with the aid of OMNEX sealant. This report is the first evidence to suggest the utility of OMNEX in renovascular surgery.

  7. Relation Between PAHs and Coal-Tar-Based Pavement Sealant in Urban Environments (Invited)

    NASA Astrophysics Data System (ADS)

    Mahler, B. J.; van Metre, P. C.

    2010-12-01

    Since 2003, coal-tar-based sealant products have come under increased scrutiny as a source of PAHs in urban environments. Sealant (or sealcoat) is the black, shiny substance often applied to asphalt pavement, in particular parking lots and driveways, for esthetic and maintenance purposes. Coal-tar-based sealant, one of the two primary pavement sealant types on the market, typically is 20-35 percent coal-tar pitch, a known carcinogen that is more than 50 percent polycyclic aromatic hydrocarbons (PAHs). The PAH content of the coal-tar-based sealant product is about 1,000 times that of a similar, asphalt-based product, on average. This difference is reflected in regional differences in sealant use and PAH concentrations in pavement dust. In the central and eastern U.S., where the coal-tar-based formulation is prevalent, ΣPAH in mobile particles from sealed pavement have been shown to be about 1,000 times higher than in the western U.S., where the asphalt-based formulation is prevalent (the median ΣPAH concentrations are 2,200 mg/kg in the central and eastern U.S. and 2.1 mg/kg in the western U.S.). Source apportionment modeling indicates that, in the central and eastern U.S., particles from sealed pavement are contributing the majority of the PAHs in recently deposited (post-1990) lake sediment, with implications for ecological health, and that coal-tar-based sealant is the primary cause of upward trends in PAHs in U.S. urban lakes. From the standpoint of human health, research indicates that mobile particles from parking lots with coal-tar-based sealant are tracked indoors, resulting in elevated PAH concentrations in house dust. Coal-tar-based sealcoat being applied to an asphalt parking lot at the University of Texas Pickle Research Center.

  8. Comparison of Various Concentrations of Tricalcium Phosphate Nanoparticles on Mechanical Properties and Remineralization of Fissure Sealants

    PubMed Central

    Tavassoli-Hojjati, Sara; Atai, Mohammad; Haghgoo, Roza; Rahimian-Imam, Sara; Kameli, Somayeh; Ahmaian-Babaki, Fatemeh; Hamzeh, Faezeh; Ahmadyar, Maryam

    2014-01-01

    Objective: The aim of this study was to investigate the mechanical properties (flexural strength, micro-shear bond strength) and remineralizing potential of fissure sealants by adding various concentrations of β-tricalcium phosphate nanoparticles. Materials and Methods: This in-vitro study consisted of five experimental groups containing prepared nano-fisssure sealants (1–5 wt.% β-TCP nanoparticles) and two control groups containing a prepared and a commercial fissure sealant. Flexural/micro-shear bond strength values were measured using Zwick test machine. Cavities on sixty healthy premolar teeth were filled with the fissure sealants containing 0–5 wt.% of nano β-TCP. The samples were assessed for remineralization under scanning electron microscopy (SEM) and EDAX. Kolmogorov-Smirnov test, One-way ANOVA and Tukey’s Post Hoc analysis/HSD were used to analyze the data. Results: There was no significant difference between the flexural strengths/elastic modulus of the 0–5 wt.% nano β-TCP groups (p>0.05). The average flexural strength/elastic modulus of the prepared fissure sealant group (0%) was significantly higher than the commercial fissure sealant group (Clinpro) (p<0.05). There was no significant difference between micro-shear bond strengths of the experimental groups (1–5 wt.%), and between the commercial and the prepared (0%) fissure sealant groups (p>0.05). Examining the samples under SEM showed a significant increase in thickness of the intermediate layer with increasing concentrations of β-TCP nanoparticles (p<0.05). Conclusion: Addition of 1–5 wt.% β-TCP nanoparticles to the fissure sealants significantly increased the remineralization potential without affecting the mechanical properties. PMID:25584048

  9. Patient blood management: use of topical hemostatic and sealant agents.

    PubMed

    Ozawa, Sherri

    2013-11-01

    Patient blood management is the scientific use of safe, effective medical and surgical techniques designed to conserve blood, prevent anemia, decrease bleeding, and optimize coagulation in an effort to improve patient outcomes. Perioperative and primary care nurses play a vital role in promoting and making the best use of patient blood management and can play a key role in implementing effective strategies that decrease or eliminate patient exposure to allogeneic blood. The fast and effective minimization of intraoperative bleeding is integral in an effective blood management program. Topical hemostatic and sealant agents can be used to improve blood conservation, reduce overall procedure time, and contribute to faster patient recovery based on specific clinical situations. The proper selection of hemostatic agents can greatly influence the patient's clinical outcomes.

  10. Improved Gain Microstrip Patch Antenna

    DTIC Science & Technology

    2015-08-06

    08-2015 Publication Improved Gain Microstrip Patch Antenna David A. Tonn Naval Under Warfare Center Division, Newport 1176 Howell St., Code 00L...Distribution A An antenna for mounting on a ground plane includes a dielectric substrate for mounting on the ground plane. A conductive patch...GAIN MICROSTRIP PATCH ANTENNA STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and used by or for the

  11. LIQUIDARMOR CM Flashing and Sealant, High Impact Technology Demonstration

    SciTech Connect

    Hun, Diana E.; Bhandari, Mahabir S.

    2016-12-01

    Air leakage is responsible for about 1.1 quads of energy or 6% of the total energy used by commercial buildings in the US. Consequently, infiltration and exfiltration are among the largest envelope-related contributors to the heating, ventilation, and air conditioning loads in commercial buildings. New air sealing technologies have recently emerged that aim to improve the performance of air barrier systems by simplifying their installation procedure. LIQUIDARMORTM CM Flashing and Sealant is an example of these new advanced material technologies. This technology is a spray-applied sealant and liquid flashing and can span gaps that are up to ¼ in. wide without a supporting material. ORNL verified the performance of LIQUIDARMORTM CM with field tests and energy simulations from a building in which LIQUIDARMORTM CM was one of components of the air barrier system. The Homeland Security Training Center (HTC) at the College of DuPage in Glen Ellyn, IL, served as the demonstration site. Blower door test results show the average air leakage rate in the demonstration site to be 0.15 cfm/ft2 at 1.57 psf, or 63% lower than the 0.4 cfm at 1.57 psf specified in the 2015 International Energy Conservation Code (IECC). According to simulation results, HTC lowered its annual heating and cooling cost by about $3,000 or 9% compared to a similar building that lacked an air barrier system. This demonstration project serves as an example of the level of building envelope airtightness that can be achieved by using air barrier materials that are properly installed, and illustrates the energy and financial savings that such an airtight envelope could attain.

  12. Fibrin glue inhibits migration of ocular surface epithelial cells.

    PubMed

    Yeung, A M; Faraj, L A; McIntosh, O D; Dhillon, V K; Dua, H S

    2016-10-01

    PurposeFibrin glue has been used successfully in numerous ophthalmic surgical procedures. Recently, fibrin glue has been used in limbal stem cell transplantation to reduce both operative time and to negate the need for sutures. The aim of this study was to determine the effects of fibrin glue on epithelial cell migration in vitro.MethodsCorneoscleral rims were split to retain the epithelial layer, Bowman's layer, and anterior stroma. Rims were cut into eight equal-sized pieces and were placed directly on culture plates or affixed with fibrin glue. Rims were maintained in culture for 25 days and epithelial cell growth was monitored. Cells were photographed to measure area or growth and immunofluorescence staining of explants for fibrin was performed.ResultsExplants that were glued demonstrated significantly delayed epithelial cell growth and migration as compared with explants without glue. By day 16, all fibrin glue had dissolved and coincided with onset of cell growth from glued explants. Cell growth commenced between days 3 and 4 for control explants without glue and around days 14-16 for explants with fibrin glue.ConclusionsFibrin glue delays epithelial cell migration by acting as a physical barrier and can potentially interfere with explant-derived limbal epithelial cell migration on to the corneal surface. We propose that glue should be used to attach the conjunctival frill of the limbal explant but care should be taken to ensure that the glue does not wrap around the explant if used to secure the explant as well. Strategic use of glue, to attach the recessed conjunctiva, can be advantageous in delaying conjunctival cell migration and reducing the need for sequential sector conjunctival epitheliectomy.

  13. Prevention of growth arrest by fibrin interposition into physeal injury.

    PubMed

    Jie, Qiang; Hu, Yunyu; Yang, Liu; Lei, Wei; Zhao, Li; Lv, Rong; Wang, Jun

    2010-03-01

    This study investigated the repair effects of fat and fibrin graft interposition through a proximal tibia transphyseal injury model and assessed the effectiveness of treatment to physeal injury with the fibrin. In this study, a unilateral growth plate injury was created in the right proximal tibia of 28 rats without any graft interposition; all left tibias were left untouched. In the other group of 28 rats, a bilateral physeal injury was made with the left tibia filled with autogenously adipose tissue and the right tibia filled with fibrin. To compare the malformed extents induced by different interventions, the length and the metaphyseal-diaphyseal angle of the tibia of three injured groups were examined. Further studies on bone density analysis and histological change were used to compare the bony bridge formation under different interventions. Results showed that the deformity angle and medial length of the tibia were significantly different between the grafted groups and nongrafted group at 4, 16, and 24 weeks postoperative (P<0.01). Results also showed no significant difference between fibrin-graft and fat-graft groups (P>0.05). Furthermore, the bone mineralization density of bony bridge induced by injury was significantly different between the grafted group and nongrafted group at 4, 16, and 24 weeks postoperative (P<0.01). Histological findings showed that bony repair after physeal injury was inhibited by both fibrin and fat interventions. We concluded that fibrin could be a substitute of adipose tissue in preventing the deformities induced by epiphyseal injury. Similar to autogenous fat, fibrin was found to alleviate limb shortness and prevent angular malformation by forming a scar instead of a bony bridge. The use of fibrin can help us to develop effective and compound intervention grafts to prevent skeletal deformity and regenerate normal cartilage tissue in the future.

  14. Microporous Nanofibrous Fibrin-based Scaffolds for Bone Tissue Engineering

    PubMed Central

    Osathanon, Thanaphum; Linnes, Michael L.; Rajachar, Rupak M.; Ratner, Buddy D.; Somerman, Martha J.; Giachelli, Cecilia M.

    2008-01-01

    The fibrotic response of the body to synthetic polymers limits their success in tissue engineering and other applications. Though porous polymers have demonstrated improved healing, difficulty in controlling their pore sizes and pore interconnections has clouded the understanding of this phenomenon. In this study, a novel method to fabricate natural polymer/calcium phosphate composite scaffolds with tightly controllable pore size, pore interconnection, and calcium phosphate deposition was developed. Microporous, nanofibrous fibrin scaffolds were fabricated using sphere-templating methods. Composite scaffolds were created by solution deposition of calcium phosphate on fibrin surfaces or by direct incorporation of nanocrystalline hydroxyapatite (nHA). The SEM results showed that fibrin scaffolds exhibited a highly porous and interconnected structure. Osteoblast-like cells, obtained from murine calvaria, attached, spread and showed a polygonal morphology on the surface of the biomaterial. Multiple cell layers and fibrillar matrix deposition were observed. Moreover, cells seeded on mineralized fibrin scaffolds exhibited significantly higher alkaline phosphatase activity as well as osteoblast marker gene expression compared to fibrin scaffolds and nHA incorporated fibrin scaffolds (0.25 g and 0.5 g). All types of scaffolds were degraded both in vitro and in vivo. Furthermore, these scaffolds promoted bone formation in a mouse calvarial defect model and the bone formation was enhanced by addition of rhBMP-2. PMID:18640716

  15. Ethinyl Estradiol and Norelgestromin Transdermal Patch

    MedlinePlus

    ... the skin. One patch is applied once a week for 3 weeks, followed by a patch-free week. Follow the directions on your prescription label carefully, ... new patch on the same day of the week (the Patch Change Day). Apply a new patch ...

  16. Validity of Sealant Retention as Surrogate for Caries Prevention – A Systematic Review

    PubMed Central

    Mickenautsch, Steffen; Yengopal, Veerasamy

    2013-01-01

    Introduction/Aim To appraise the clinical literature in determining whether loss of complete sealant retention as surrogate endpoint is directly associated with caries occurrence on sealed teeth as its clinical endpoint and to apply the appraised evidence in testing the null-hypothesis that the retention/caries ratio between different types of sealant materials (resin and glass-ionomer cement) is not statistically significant ( = Prentice criterion for surrogate endpoint validity). Methods Databases searched PubMed/Medline, Directory of Open Access Journals; IndMed, Scielo. Systematic reviews were checked for suitable trials. The search terms: “fiss* AND seal*” and “fissure AND sealant” were used. Article selection criteria were: clinical trial reporting on the retention and caries occurrence of resin and/or glass-ionomer cement (GIC) fissure sealed permanent molar teeth; minimum 24-month follow-up period; systematic review or meta-analysis. Datasets and information were extracted from accepted trials. The principle outcome measure was the ratio of Risk of loss of complete retention to the Risk of caries occurrence per sealant type (RCR). Risk of bias was assessed in trials and sensitivity analysis with regard to potential confounding factors conducted. The null-hypothesis was tested by graphical and statistical methods. Results The risk of loss of complete retention of sealant materials was associated with the risk of caries occurrence for resin but not for GIC based sealants. The difference between RCR values of the two sealant types was statistically significant (p<0.05). The null-hypothesis was rejected. Conclusions The current clinical evidence suggests that complete retention of pit and fissure sealants may not be a valid surrogate endpoint for caries prevention as its clinical endpoint. Further research is required to corroborate the current results. PMID:24194861

  17. Microstructural and mechanical differences between digested collagen-fibrin co-gels and pure collagen and fibrin gels.

    PubMed

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

    2012-11-01

    Collagen and fibrin are important extracellular 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 the respective pure collagen or fibrin gels of the same protein concentration. The morphologies of the collagen networks were further analyzed via three-dimensional network reconstruction from confocal image z-stacks. Both collagen and fibrin exhibited a decrease in mean fiber diameter when formed in co-gels compared with the pure gels. This microstructural change was accompanied by an increased failure strain and decreased tangent modulus for both collagen and fibrin following selective digestion of the co-gels. In addition, analysis of the reconstructed collagen networks indicated the presence of very long fibers and the clustering of fibrils, resulting in very high connectivities for collagen networks formed in co-gels.

  18. 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

  19. 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

    2016-03-03

    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.

  20. 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

  1. 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.

  2. PAH Concentrations Decline Following 2006 Ban on Coal-Tar-Based Pavement Sealants in Austin, Texas

    NASA Astrophysics Data System (ADS)

    Van Metre, P. C.; Mahler, B. J.

    2013-12-01

    Recent studies have concluded that coal-tar-based pavement sealants (CT sealants) are a major source of polycyclic aromatic hydrocarbons (PAHs) in non-industrial urban settings in the United States. In 2006, Austin, TX, became the first jurisdiction in the U.S. to ban the use of CT sealants. We evaluated PAH concentrations following the ban by analyzing sediment cores collected from Lady Bird Lake in 2012; Lady Bird Lake impounds the Colorado River in central Austin and receives runoff from much of the greater Austin area. The mean sum concentration of the 16 U.S. Environmental Protection Agency Priority Pollutant PAHs (∑PAH16) in one of two 2012 sediment cores analyzed for PAHs declined 75% from before 2006 (mean of 4 samples=8,090 μg kg-1) to 2012 (mean of 2 samples=2,030 μg kg-1), reversing a 40-year (1959-1999) upward trend in PAH concentrations that was previously documented. The downward trend in PAH concentrations in the seven uppermost 1 cm sampling intervals in the first 2012 core was statistically significant (r=0.93, p-value=0.002). Post-2008 PAH trends in the second 2012 core were similar (significant downward trend in the six uppermost 1 cm sampling intervals and mean 2012 ∑PAH16 of 2,390 μg kg-1); however, pre-2007 sediment did not appear to have been preserved in this core likely because of the effects of flooding on sediment deposition and mixing at this site--the largest flood on the Colorado River in Austin in 20 years was in 2007. On the basis of a comparison of lake-sediment PAH profiles to 22 PAH source profiles, the PAH loading to lake sediment continues to be dominated by CT sealants. The continued dominance of proportional PAH loading by CT sealants in spite of decreased concentrations since 2006 might be because legacy CT sealant and contaminated soils and sediments continue to yield PAHs to runoff. A previous study using source-receptor modeling concluded that CT sealants were the largest PAH source to 40 urban lakes studied in the

  3. Foam-like compression behavior of fibrin networks

    PubMed Central

    Litvinov, Rustem I.; Weisel, John W.; Alber, Mark S.; Purohit, Prashant K.

    2016-01-01

    The rheological properties of fibrin networks have been of long-standing interest. As such there is a wealth of studies of their shear and tensile responses, but their compressive behavior remains unexplored. Here, by characterization of the network structure with synchronous measurement of the fibrin storage and loss moduli at increasing degrees of compression, we show that the compressive behavior of fibrin networks is similar to that of cellular solids. A non-linear stress-strain response of fibrin consists of three regimes: 1) an initial linear regime, in which most fibers are straight, 2) a plateau regime, in which more and more fibers buckle and collapse, and 3) a markedly non-linear regime, in which network densification occurs by bending of buck-led fibers and inter-fiber contacts. Importantly, the spatially non-uniform network deformation included formation of a moving “compression front” along the axis of strain, which segregated the fibrin network into compartments with different fiber densities and structure. The Young’s modulus of the linear phase depends quadratically on the fibrin volume fraction while that in the densified phase depends cubically on it. The viscoelastic plateau regime corresponds to a mixture of these two phases in which the fractions of the two phases change during compression. We model this regime using a continuum theory of phase transitions and analytically predict the storage and loss moduli which are in good agreement with the experimental data. Our work shows that fibrin networks are a member of a broad class of natural cellular materials which includes cancellous bone, wood and cork. PMID:25982442

  4. 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.

  5. Foam-like compression behavior of fibrin networks.

    PubMed

    Kim, Oleg V; Liang, Xiaojun; Litvinov, Rustem I; Weisel, John W; Alber, Mark S; Purohit, Prashant K

    2016-02-01

    The rheological properties of fibrin networks have been of long-standing interest. As such there is a wealth of studies of their shear and tensile responses, but their compressive behavior remains unexplored. Here, by characterization of the network structure with synchronous measurement of the fibrin storage and loss moduli at increasing degrees of compression, we show that the compressive behavior of fibrin networks is similar to that of cellular solids. A nonlinear stress-strain response of fibrin consists of three regimes: (1) an initial linear regime, in which most fibers are straight, (2) a plateau regime, in which more and more fibers buckle and collapse, and (3) a markedly nonlinear regime, in which network densification occurs by bending of buckled fibers and inter-fiber contacts. Importantly, the spatially non-uniform network deformation included formation of a moving "compression front" along the axis of strain, which segregated the fibrin network into compartments with different fiber densities and structure. The Young's modulus of the linear phase depends quadratically on the fibrin volume fraction while that in the densified phase depends cubically on it. The viscoelastic plateau regime corresponds to a mixture of these two phases in which the fractions of the two phases change during compression. We model this regime using a continuum theory of phase transitions and analytically predict the storage and loss moduli which are in good agreement with the experimental data. Our work shows that fibrin networks are a member of a broad class of natural cellular materials which includes cancellous bone, wood and cork.

  6. In vitro study of Streptococcus mutans adhesion on composite resin coated with three surface sealants

    PubMed Central

    Kim, Da Hye

    2017-01-01

    Objectives Although the coating of surface sealants to dental composite resin may potentially reduce bacterial adhesion, there seems to be little information regarding this issue. This preliminary in vitro study investigated the adhesion of Streptococcus mutans (S. mutans) on the dental composite resins coated with three commercial surface sealants. Materials and Methods Composite resin (Filtek Z250) discs (8 mm in diameter, 1 mm in thickness) were fabricated in a mold covered with a Mylar strip (control). In group PoGo, the surfaces were polished with PoGo. In groups PS, OG, and FP, the surfaces polished with PoGo were coated with the corresponding surface sealants (PermaSeal, PS; OptiGuard, OG; Fortify Plus, FP). The surfaces of the materials and S. mutans cells were characterized by various methods. S. mutans adhesion to the surfaces was quantitatively evaluated using flow cytometry (n = 9). Results Group OG achieved the lowest water contact angle among all groups tested (p < 0.001). The cell surface of S. mutans tested showed hydrophobic characteristics. Group PoGo exhibited the greatest bacterial adhesion among all groups tested (p < 0.001). The sealant-coated groups showed statistically similar (groups PS and FP, p > 0.05) or significantly lower (group OG, p < 0.001) bacterial adhesion when compared with the control group. Conclusions The application of the surface sealants significantly reduced S. mutans adhesion to the composite resin polished with the PoGo. PMID:28194363

  7. Impact of adhesive and photoactivation method on sealant integrity and polymer network formation.

    PubMed

    Borges, Boniek Castillo Dutra; Pereira, Fabrício Lopes da Rocha; Alonso, Roberta Caroline Bruschi; Braz, Rodivan; Montes, Marcos Antônio Japiassú Resende; Pinheiro, Isauremi Vieira de Assunção; Santos, Alex José Souza dos

    2012-01-01

    We evaluated the influence of photoactivation method and hydrophobic resin (HR) application on the marginal and internal adaptation, hardness (KHN), and crosslink density (CLD) of a resin-based fissure sealant. Model fissures were created in bovine enamel fragments (n = 10) and sealed using one of the following protocols: no adhesive system + photoactivation of the sealant using continuous light (CL), no adhesive system + photoactivation of the sealant using the soft-start method (SS), HR + CL, or HR + SS. Marginal and internal gaps and KHN were assessed after storage in water for 24 h. The CLD was indirectly assessed by repeating the KHN measurement after 24 h of immersion in 100% ethanol. There was no difference among the samples with regard to marginal or internal adaptation. The KHN and CLD were similar for samples cured using either photoactivation method. Use of a hydrophobic resin prior to placement of fissure sealants and curing the sealant using the soft-start method may not provide any positive influence on integrity or crosslink density.

  8. Sealant retention is better assessed through colour photographs than through the replica and the visual examination methods.

    PubMed

    Hu, Xuan; Fan, Mingwan; Rong, Wensheng; Lo, Edward C M; Bronkhorst, Ewald; Frencken, Jo E

    2014-08-01

    The aim of this study was to test the hypothesis that the colour photograph method has a higher level of validity for assessing sealant retention than the visual clinical examination and replica methods. Sealed molars were assessed by two evaluators. The scores for the three methods were compared against consensus scores derived through assessing retention from scanning electron microscopy images (reference standard). The presence/absence (survival) of retained sealants on occlusal surfaces was determined according to the traditional and modified categorizations of retention. Sensitivity, specificity, and Youden-index scores were calculated. Sealant retention assessment scores for visual clinical examinations and for colour photographs were compared with those of the reference standard on 95 surfaces, and sealant retention assessment scores for replicas were compared with those of the reference standard on 33 surfaces. The highest mean Youden-index score for the presence/absence of sealant material was observed for the colour photograph method, followed by that for the replica method; the visual clinical examination method scored lowest. The mean Youden-index score for the survival of retained sealants was highest for the colour photograph method for both the traditional (0.882) and the modified (0.768) categories of sealant retention, whilst the visual clinical examination method had the lowest Youden-index score for these categories (0.745 and 0.063, respectively). The colour photograph method had a higher validity than the replica and the visual examination methods for assessing sealant retention.

  9. 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.

  10. 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

  11. Weight reduction is associated with increased plasma fibrin clot lysis.

    PubMed

    Brzezińska-Kolarz, Beata; Kolarz, Marek; Wałach, Angelika; Undas, Anetta

    2014-11-01

    Obesity is associated with an increased risk of vascular thrombotic events. We sought to investigate how obesity and weight loss affect plasma fibrin clot properties. A total of 29 obese patients were studied before and after 3-month low-fat diet. Plasma fibrin clot parameters, including fibrin clot permeation coefficient (Ks), the lag phase of the turbidity curve, clot lysis time (t 50%), maximum rate of increase in D-dimer levels, and maximum D-dimer concentrations, were determined. Low-fat diet resulted in the reduction of body weight (P < .0001), body mass index (P < .0001), fat mass (P < .0001), total cholesterol (P < .0001), low-density lipoprotein cholesterol (P = .0005), triglycerides (P = .008), and plasminogen activator inhibitor 1 (P = .02), but not in fibrinogen or C-reactive protein. The only change in fibrin clot variables was shorter t 50% (P = .02). Baseline t 50%, but not posttreatment, correlated with waist circumference (r = .44, p = .02). This study demonstrates that weight loss in obese people can increase the efficiency of fibrin clot lysis.

  12. Phase-separated chitosan-fibrin microbeads for cell delivery.

    PubMed

    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.

  13. Measurement of clottability of fibrin polymers using magnetic orientation

    NASA Astrophysics Data System (ADS)

    Iwasaka, M.; Ueno, S.; Tsuda, H.

    1996-04-01

    Fibrin polymers, as a kind of diamagnetic material, are oriented parallel to the direction of magnetic fields. We investigated the polymerization of partially digested fibrinogens in an 8 T magnetic field in order to observe the clotting ability of various sizes of fibrinogen fractions using a magnetic orientation technique. We purified high-molecular weight fraction (F1) and low-molecular weight fraction from human fibrinogen (F2). Fibrin gels were formed in an 8 T magnetic field for 9 h, and transmittancies were measured to evaluate the degree of magnetic orientation. The results show that a lack at the C-terminal half of one Aα chain did not affect the magnetic orientation of fibrin. We also investigated the effect of the digestion of fibrinogen by plasmin on the magnetic orientation of fibrin. The result shows that partially digested fibrin molecules also orient in an 8 T magnetic field. However, the degree of magnetic orientation significantly decreases when fragment X and fragment Y appear.

  14. 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

  15. 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.

  16. 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.

  17. Fibrin-fiber architecture influences cell spreading and differentiation

    PubMed Central

    Bruekers, Stéphanie M. C.; Jaspers, Maarten; Hendriks, José M. A.; Kurniawan, Nicholas A.; Koenderink, Gijsje H.; Kouwer, Paul H. J.; Rowan, Alan E.; T. S. Huck, Wilhelm

    2016-01-01

    ABSTRACT The mechanical and structural properties of the extracellular matrix (ECM) play an important role in regulating cell fate. The natural ECM has a complex fibrillar structure and shows nonlinear mechanical properties, which are both difficult to mimic synthetically. Therefore, systematically testing the influence of ECM properties on cellular behavior is very challenging. In this work we show two different approaches to tune the fibrillar structure and mechanical properties of fibrin hydrogels. Addition of extra thrombin before gelation increases the protein density within the fibrin fibers without significantly altering the mechanical properties of the resulting hydrogel. On the other hand, by forming a composite hydrogel with a synthetic biomimetic polyisocyanide network the protein density within the fibrin fibers decreases, and the mechanics of the composite material can be tuned by the PIC/fibrin mass ratio. The effect of the changes in gel structure and mechanics on cellular behavior are investigated, by studying human mesenchymal stem cell (hMSC) spreading and differentiation on these gels. We find that the trends observed in cell spreading and differentiation cannot be explained by the bulk mechanics of the gels, but correlate to the density of the fibrin fibers the gels are composed of. These findings strongly suggest that the microscopic properties of individual fibers in fibrous networks play an essential role in determining cell behavior. PMID:26910190

  18. Modification of silicone sealant to improve gamma radiation resistance, by addition of protective agents

    NASA Astrophysics Data System (ADS)

    González-Pérez, Giovanni; Burillo, Guillermina

    2013-09-01

    Poly (dimethylsiloxane) (PDMS) sealant (SS) was modified with the addition of different protective compounds to conserve its physical-chemical properties during gamma irradiation. 2-Vinyl naphthalene (2-VN), bisphenol-A (BPA) and poly (vinyl carbazole) (PVK) were used to evaluate radiation protection through the crosslinking effect of radiation. The samples were irradiated with doses from 100 kGy to 500 kGy at room temperature in air, with a 60Co gamma source, and the changes in molecular weight, thermal behavior, elastic properties and infrared spectra (FTIR-ATR) absorbance analysis were determined. The molecular weight of unmodified silicone sealant increases with the absorbed dose because of crosslinking as predominant effect. However, the crosslinking effect was inhibited with the addition of protective agent due to the aromatic compounds present. Modified silicone sealant films present better radiation resistance than unmodified system.

  19. An in-vitro evaluation of mechanical and esthetic properties of orthodontic sealants

    PubMed Central

    Premaraj, Thyagaseely Sheela; Rohani, Nima; Covey, David; Premaraj, Sundaralingam; Hua, Yi; Watanabe, Hidehiko

    2014-01-01

    Objective: To evaluate mechanical and esthetic Properties of two commercially available orthodontic sealants: Opal®Seal (OS) and L.E.D. Pro Seal (PS). Materials and Methods: Discs of each sealant were prepared to test the following properties: Micro hardness, wear resistance and color stability. Samples were randomly selected after the wear test for SEM imaging to analyze surface morphology. Results: OS was significantly harder than PS (P < 0.001). PS was significantly more wear resistant than OS (P < 0.05). PS showed a greater ∆E*ab (increased staining) when placed in wine or coffee showing a significant difference (P < 0.05). SEM showed particle size, shape and distribution were different for PS and OS reflecting the pattern seen on wear surfaces. Conclusion: Both orthodontic sealants are beneficial for protecting enamel. However with better wear properties PS was superior in resisting mechanical stresses. OS was more color stable. PMID:25512729

  20. Glass-ceramic sealant for solid oxide fuel cells application: Characterization and performance in dual atmosphere

    NASA Astrophysics Data System (ADS)

    Sabato, A. G.; Cempura, G.; Montinaro, D.; Chrysanthou, A.; Salvo, M.; Bernardo, E.; Secco, M.; Smeacetto, F.

    2016-10-01

    A glass-ceramic composition was designed and tested for use as a sealant in solid oxide fuel cell (SOFC) planar stack design. The crystallization behaviour was investigated by calculating the Avrami parameter (n) and the activation energy for crystallization (Ec) was obtained. The calculated values for n and Ec were 3 and 413.5 kJ/mol respectively. The results of thermal analyses indicate that this composition shows no overlap between the sintering and crystallization stages and thus an almost pore-free sealant can be deposited and sintered at 850 °C in air for 30 min. A gas tightness test has been carried out at 800 °C for 1100 h in dual atmosphere (Ar-H2 and air) without recording any leakage. Morphological and crystalline phase analyses were conducted prior and following tests in dual atmospheres in order to assess the compatibility of the proposed sealant with the metallic interconnect.

  1. Comparison between visual clinical examination and the replica method for assessments of sealant retention over a 2-year period

    PubMed Central

    Hu, Xuan; Chen, Xi; Ye, Lu; Fan, Ming-Wen; Huysmans, Marie-Charlotte; Frencken, Jo E

    2014-01-01

    To compare the levels of agreement and the survival rates of sealant retention for different sealing materials over a 2-year period assessed using the visual clinical examination and replica methods, sealant retention data were obtained by visual clinical examination and from replicas of the same sealed tooth at baseline and at 0.5-, 1- and 2-year evaluation points in 407 children and were compared for agreement using kappa coefficients. Survival curves of retained sealants on occlusal surfaces were created using modified categorisation (fully retained sealants and those having all pits and fissures partly covered with the sealant material versus completely lost sealants that included pit and fissure systems that had ≥1 pit re-exposed) according to the Kaplan–Meier method. The kappa coefficient for the agreement between both assessment methods over the three evaluation time points combined was 0.38 (95% confidence interval (CI): 0.35–0.41). More sealant retention was observed from replicas than through visual clinical examination. Cumulative survival curves at the three evaluation times were not statistically significantly higher when assessed from replicas (P=0.47). Using the replica method, more retained sealant material was observed than through visual clinical examination during the 2-year period. This finding did not result in a difference in the survival rates of sealants assessed by the two assessment methods. When replicas cast in die stone are used for assessing sealant retention, the level of reliability of the data is higher than that of data obtained through the commonly used visual clinical examination, particularly if such assessments are conducted over time. PMID:24625469

  2. Characterisation and microleakage of a new hydrophilic fissure sealant - UltraSeal XT® hydro™

    PubMed Central

    GÜÇLÜ, Zeynep A.; DÖNMEZ, Nazmiye; HURT, Andrew P.; COLEMAN, Nichola J.

    2016-01-01

    ABSTRACT Objectives The aim of this study was to characterise the new hydrophilic fissure sealant, UltraSeal XT® hydro™ (Ultradent Products, USA), and to investigate its in vitro resistance to microleakage after placement on conventionally acid etched and sequentially lased and acid etched molars. Material and Methods The sealant was characterised by Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and Vickers indentation test. Occlusal surfaces of extracted human molars were either conventionally acid etched (n=10), or sequentially acid etched and laser irradiated (n=10). UltraSeal XT® hydro™ was applied to both groups of teeth which were then subjected to 2,500 thermocycles between 5 and 55°C prior to microleakage assessment by fuchsin dye penetration. Results UltraSeal XT® hydro™ is an acrylate-based sealant that achieved a degree of conversion of 50.6±2.2% and a Vickers microhardness of 24.2±1.5 under standard light curing (1,000 mWcm-2 for 20 s). Fluoride ion release is negligible within a 14-day period. SEM and EDX analyses indicated that the sealant comprises irregular submicron and nano-sized silicon-, barium-, and aluminium-bearing filler phases embedded in a ductile matrix. Laser preconditioning was found to significantly reduce microleakage (Mann-Whitney U test, p<0.001). The lased teeth presented enhanced surface roughness on a 50 to 100 μm scale that caused the segregation and concentration of the filler particles at the enamel-sealant interface. Conclusion Laser preconditioning significantly decreased microleakage and increased enamel surface roughness, which caused zoning of the filler particles at the enamel-sealant interface. PMID:27556205

  3. 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.

  4. Enamel Surface with Pit and Fissure Sealant Containing 45S5 Bioactive Glass.

    PubMed

    Yang, S-Y; Kwon, J-S; Kim, K-N; Kim, K-M

    2016-05-01

    Enamel demineralization adjacent to pit and fissure sealants leads to the formation of marginal caries, which can necessitate the replacement of existing sealants. Dental materials with bioactive glass, which releases ions that inhibit dental caries, have been studied. The purpose of this study was to evaluate the enamel surface adjacent to sealants containing 45S5 bioactive glass (BAG) under simulated microleakage between the material and the tooth in a cariogenic environment. Sealants containing 45S5BAG filler were prepared as follows: 0% 45S5BAG + 50.0% glass (BAG0 group), 12.5% 45S5BAG + 37.5% glass (BAG12.5 group), 25.0% 45S5BAG + 25.0% glass (BAG25.0 group), 37.5% 45S5BAG + 12.5% glass (BAG37.5 group), and 50.0% 45S5BAG + 0% glass (BAG50.0 group). A cured sealant disk was placed over a flat bovine enamel disk, separated by a 60-µm gap, and immersed in lactic acid solution (pH 4.0) at 37 °C for 15, 30, and 45 d. After the storage period, each enamel disk was separated from the cured sealant disk, and the enamel surface was examined with optical 3-dimensional surface profilometer, microhardness tester, and scanning electron microscopy. The results showed a significant increase in roughness and a decrease in microhardness of the enamel surface as the proportion of 45S5BAG decreased (P< 0.05). In the scanning electron microscopy images, enamel surfaces with BAG50.0 showed a smooth surface, similar to those in the control group with distilled water, even after prolonged acid storage. Additionally, an etched pattern was observed on the surface of the demineralized enamel with a decreasing proportion of 45S5BAG. Increasing the 45S5BAG filler contents of the sealants had a significant impact in preventing the demineralization of the enamel surface within microgaps between the material and the tooth when exposed to a cariogenic environment. Therefore, despite some marginal leakage, these novel sealants may be effective preventive dental materials for inhibiting

  5. Estrogenicity of bisphenol A released from sealants and composites: a review of the literature

    PubMed Central

    Eramo, Stefano; Urbani, Giacomo; Sfasciotti, Gian Luca; Brugnoletti, Orlando; Bossù, Maurizio; Polimeni, Antonella

    2011-01-01

    Summary This study aims to critically summarize the literature about bisphenol A (BPA), indicate whether and how those risks are real and emphasize how it is eventually possible to prevent them. With this in mind, we should consider nature, risks and control of BPA, as well as its presence and its role in sealants and composites. It is important to note that we will focus on literature exclusively written about the possible estrogenic activity (and not about the general toxicology profile) of BPA or its possible derivatives released from composites and sealants (without mentioning, or covering just briefly, similar activities performed by their components). PMID:22238710

  6. Estimating emissions from adhesives and sealants uses and manufacturing for environmental risk assessments.

    PubMed

    Tolls, Johannes; Gómez, Divina; Guhl, Walter; Funk, Torsten; Seger, Erich; Wind, Thorsten

    2016-01-01

    Regulation (EC) No 1907/2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) requires that environmental exposure assessments be performed for all uses of dangerous substances that are marketed in the European Union in quantities above 10 tons per year. The quantification of emissions to the environment is a key step in this process. This publication describes the derivation of release factors and gives guidance for estimating use rates for quantifying the emissions from the manufacturing and application of adhesives and sealants. Release factors available for coatings and paints are read across to adhesives or sealants based on similarities between these 2 product groups with regard to chemical composition and to processing during manufacturing and application. The granular emission scenarios in these documents are mapped to the broad emission scenarios for adhesives or sealants. According to the mapping, the worst-case release factors for coatings or paints are identified and assigned to the adhesives or sealants scenarios. The resulting 10 specific environmental release categories (SPERCs) for adhesives and sealants are defined by differentiating between solvent and nonsolvent ingredients and between water-borne and solvent-borne or solvent-free products. These cover the vast majority of the production processes and uses and are more realistic than the 5 relevant emission estimation defaults provided in the REACH guidance. They are accompanied with adhesive or sealant consumption rates in the EU and with guidance for estimating conservative substance use rates at a generic level. The approach of combining conservative SPERC release factors with conservative estimates of substance rates is likely to yield emission estimates that tend to overpredict actual releases. Because this qualifies the approach for use in lower-tier environmental exposure assessment, the Association of the European Adhesive & Sealant Industry

  7. 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

  8. Fibrin activates GPVI in human and mouse platelets.

    PubMed

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

    2015-09-24

    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.

  9. Vasculogenesis and Angiogenesis in Modular Collagen-Fibrin Microtissues.

    PubMed

    Peterson, A W; Caldwell, D J; Rioja, A Y; Rao, R R; Putnam, A J; Stegemann, J P

    2014-10-01

    The process of new blood vessel formation is critical in tissue development, remodeling and regeneration. Modular tissue engineering approaches have been developed to enable the bottom-up assembly of more complex tissues, including vascular networks. In this study, collagen-fibrin composite microbeads (100-300 μm in diameter) were fabricated using a water-in-oil emulsion technique. Human endothelial cells and human fibroblasts were embedded directly in the microbead matrix at the time of fabrication. Microbead populations were characterized and cultured for 14 days either as free-floating populations or embedded in a surrounding fibrin gel. The collagen-fibrin matrix efficiently entrapped cells and supported their viability and spreading. By 7 days in culture, endothelial cell networks were evident within microbeads, and these structures became more prominent by day 14. Fibroblasts co-localized with endothelial cells, suggesting a pericyte-like function, and laminin deposition indicated maturation of the vessel networks over time. Microbeads embedded in a fibrin gel immediately after fabrication showed the emergence of cells and the coalescence of vessel structures in the surrounding matrix by day 7. By day 14, inosculation of neighboring cords and prominent vessel structures were observed. Microbeads pre-cultured for 7 days prior to embedding in fibrin gave rise to vessel networks that emanated radially from the microbead by day 7, and developed into connected networks by day 14. Lumen formation in endothelial cell networks was confirmed using confocal sectioning. These data show that collagen-fibrin composite microbeads support vascular network formation. Microbeads embedded directly after fabrication emulated the process of vasculogenesis, while the branching and joining of vessels from pre-cultured microbeads resembled angiogenesis. This modular microtissue system has utility in studying the processes involved in new vessel formation, and may be developed into

  10. Fibrin Adhesive: Clinical Application in Coronary Artery Bypass Graft Surgery

    PubMed Central

    Fundaró, Pino; Velardi, Antonio R.; Santoli, Carmine

    1985-01-01

    Fibrin adhesive was used 72 times in a group of 67 patients undergoing elective coronary artery bypass graft surgery. The indications were prophylactic sealing of potential sources of bleeding, topical hemostasis (control of bleeding sites dangerous or difficult to suture), and fixation of the graft in the optimal position. The method of glue application under varying circumstances is described and the results are reported. This experience suggests that in some cases the glue expedites the operation and makes it safer. We conclude that the fibrin sealing represents a valid aid in coronary artery bypass graft surgery. PMID:15227018

  11. 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

  12. Fibrin glue improves the therapeutic effect of MSCs by sustaining survival and paracrine function.

    PubMed

    Kim, Inok; Lee, Sung Koo; Yoon, Jung In; Kim, Da Eun; Kim, Mihyung; Ha, Hunjoo

    2013-11-01

    Fibrin glue has been widely investigated as a cell delivery vehicle for improving the therapeutic effects of mesenchymal stem cells (MSCs). Implanted MSCs produce their therapeutic effects by secreting paracrine factors and by replacing damaged tissues after differentiation. While the influence of fibrin glue on the differentiation potential of MSCs has been well documented, its effect on paracrine function of MSCs is largely unknown. Herein we investigated the influence of fibrin glue on the paracrine effects of MSCs. MSCs were isolated from human adipose tissue. The effects of fibrin glue on survival, migration, secretion of growth factors, and immune suppression of MSCs were investigated in vitro. MSCs in fibrin glue survived and secreted growth factors such as the vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) over 14 days. VEGF and immune modulators, including the transforming growth factor (TGF)-β1 and prostaglandin E2, secreted from MSCs in fibrin glue significantly increased under inflammatory conditions. Thus, MSCs in fibrin glue effectively suppressed immune reactions. In addition, fibrin glue protected the MSCs from oxidative stress and prevented human dermal fibroblast death induced by exposure to extreme stress. In contrast, MSCs within fibrin glue hardly migrated. These results suggest that fibrin glue may sustain survival of implanted MSCs and their paracrine function. Our results provide a mechanistic data to allow further development of MSCs with fibrin glue as a clinical treatment.

  13. 40 CFR Table 4 to Subpart Xxxx of... - Operating Limits for Puncture Sealant Application Control Devices

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... performance test. 2. Carbon adsorber (regenerative) to which puncture sealant application spray booth emissions are ducted a. Maintain the total regeneration mass, volumetric flow, and carbon bed temperature at the operating range established during the performance test.b. Reestablish the carbon bed...

  14. 40 CFR Table 4 to Subpart Xxxx of... - Operating Limits for Puncture Sealant Application Control Devices

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... established during the performance test. 2. Carbon adsorber (regenerative) to which puncture sealant... carbon bed temperature at the operating range established during the performance test.b. Reestablish the carbon bed temperature to the levels established during the performance test within 15 minutes of...

  15. 40 CFR Table 4 to Subpart Xxxx of... - Operating Limits for Puncture Sealant Application Control Devices

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... performance test. 2. Carbon adsorber (regenerative) to which puncture sealant application spray booth emissions are ducted a. Maintain the total regeneration mass, volumetric flow, and carbon bed temperature at the operating range established during the performance test.b. Reestablish the carbon bed...

  16. Effects of porous-hydroxyapatite incorporated into glass-ionomer sealants.

    PubMed

    Shinonaga, Yukari; Arita, Kenji; Nishimura, Takako; Chiu, Szu-Yu; Chiu, Hsiu-Hui; Abe, Yoko; Sonomoto, Mie; Harada, Kyoko; Nagaoka, Noriyuki

    2015-01-01

    The purpose of the present study was to evaluate the mechanical and chemical properties of a novel glass ionomer cement for use as a pit and fissure sealant containing a porous hydroxyapatite, namely, apatite ionomer cement (AIC). Control sealant samples were used Fuji III (GIC-S). The experiment sealant samples (AIC-S) consisted of porous spherical hydroxyapatite (HApS) particles added at 28 wt% to GIC-S powder. The GIC-S and AIC-S samples were evaluated through mechanical strength measurements, scanning electron microscopy observations, energy dispersive X-ray spectroscopy analysis, fluoride ion release tests, and antibacterial tests. The flexural strength of the AIC-S was significantly higher than that of GIC-S for each period, 1 h, 24 h and 1 year. The fluoride release dose for AIC-S was consistently higher than that for GIC-S. In addition, the antibacterial properties of AIC-S were superior to those of GIC-S. The novel AIC-S may be a more suitable sealant material for pits and fissures with intact and/or infected enamel.

  17. In vitro evaluation of shear bond strength and microleakage of different pit and fissure sealants

    PubMed Central

    Babaji, Prashant; Vaid, Shivali; Deep, S.; Mishra, Samvit; Srivastava, Madhulika; Manjooran, Thomas

    2016-01-01

    Aim and Objectives: Fissure caries is most common in children due to deep pit and fissures. Pit and fissure areas on the occlusal surface of the teeth make them susceptible to dental caries, which need to be prevented or restored. Fissures sealant reduces the risk of occlusal caries. The present study was done to evaluate microleakage and shear bond strength of various fissure sealants. Materials and Methods: Thirty-six extracted molars were randomly allocated equally (n = 12) into three groups with three different sealants to evaluate shear bond strength and microleakage at sealant space. The shear bond strengths was evaluated with one-way analysis of variance and microleakage by Kruskal-Wallis nonparametric test using the Statistical Package for the Social Sciences version 18.0 (Chicago: SPSS Inc, 2009). Results: Tetric flow (16.8 MPa) recorded the highest shear bond strength and the difference was statistically significant with enamel loc (12.8 MPa). There was no statistically significant difference in relation to microleakage (P > 0.05) in the tested groups. Conclusions: Tetric flow recorded the highest shear bond strength and the difference was statistically significant with enamel loc. However, there was no statistically significant difference among the groups regarding microleakage. PMID:27652241

  18. 40 CFR Table 3 to Subpart Xxxx of... - Emission Limits for Puncture Sealant Application Affected Sources

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... application spray booth Reduce spray booth HAP (measured as volatile organic compounds (VOC)) emissions by at... sealant application spray booth Reduce spray booth HAP (measured as VOC) emissions by at least 95 percent... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Emission Limits for Puncture...

  19. 40 CFR Table 3 to Subpart Xxxx of... - Emission Limits for Puncture Sealant Application Affected Sources

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... application spray booth Reduce spray booth HAP (measured as volatile organic compounds (VOC)) emissions by at... sealant application spray booth Reduce spray booth HAP (measured as VOC) emissions by at least 95 percent... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Emission Limits for Puncture...

  20. Effects of aging on surface properties and adhesion of Streptococcus mutans on various fissure sealants.

    PubMed

    Bürgers, Ralf; Cariaga, Tashiana; Müller, Rainer; Rosentritt, Martin; Reischl, Udo; Handel, Gerhard; Hahnel, Sebastian

    2009-12-01

    The aim of the present study was the quantification of Streptococcus mutans adhesion on ten widely used pit and fissure sealant materials and the correlation of these findings to surface roughness (R(a)) and surface free energy (SFE). Additionally, changes in streptococcal adhesion and surface parameters after water immersion and artificial aging have been investigated. Circular specimens of ten fissure sealants (seven resin-based composites, two glass ionomers, and one compomer) were made and polished. Surface roughness was determined by perthometer and SFE by goniometer measurements. Sealant materials were incubated with S. mutans suspension (2.5 h, 37 degrees C), and adhering bacteria were quantified by using a biofluorescence assay in combination with an automated plate reader. Surface properties and S. mutans adhesion were measured prior to and after water immersion after 1 and 6 months and after additional thermocycling (5,000 cycles; 5 degrees C/55 degrees C). The tested sealants showed significant differences in S. mutans adhesion prior to and after the applied aging procedures. Aging resulted in slight increases (mostly <0.2 microm) in surface roughness, as well as in significant decreases in SFE and in significantly lower quantities of adhering bacteria. Ketac Bond and UltraSeal XT plus revealed the lowest adhesion potential after artificial aging. In general, the amount of adhering S. mutans was reduced after aging, which may be related to the decline in SFEs.

  1. INVESTIGATION OF THE POTENTIAL ANTIMICROBIAL EFFICACY OF SEALANTS USED IN HVAC SYSTEMS

    EPA Science Inventory

    The paper gives results of an investigation of the potential antimicrobial efficacy of sealants used in heating, ventilation and air-conditioning systems. Recent experiments confirm field experience that duct cleaning alone may not provide adequate protection from regrowth of fu...

  2. The utilization of dental hygiene students in school-based dental sealant programs.

    PubMed

    Miller, Faith Y

    2005-01-01

    Early detection of childhood caries is important to childrens' overall health. Untreated childhood caries can lead to pain, as in abscesses from prolonged neglect; altered dietary intake; and delays in the development of the permanent teeth if the primary teeth are prematurely lost. In the summer of 2000, funds were provided to various oral health care provider organizations by the Illinois Department of Public Health, Division of Oral Health, to purchase portable equipment to deliver preventive services (i.e., exams, sealants, and oral hygiene education) to second-grade and sixth-grade children who qualified for Medicaid and/or free and reduced-cost lunch programs. The Dental Sealant Grant Program at Southern Illinois University in Carbondale was a unique program that utilized dental hygiene students as the primary human resource. Within the state, the Dental Sealant Grant Program was, at the time of this report, the only grantee sponsored by a stand-alone dental hygiene program (not affiliated with a dental school). Other positive aspects of the dental hygiene-sponsored sealant program were that the supervising dentist was the primary Medicaid provider and a member of the dental hygiene faculty; dental hygiene faculty participated actively as site coordinators and clinicians; and dental hygiene students were given the opportunity to volunteer for the program as a service-learning option.

  3. 40 CFR Table 4 to Subpart Xxxx of... - Operating Limits for Puncture Sealant Application Control Devices

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... established during the performance test. 2. Carbon adsorber (regenerative) to which puncture sealant... carbon bed temperature at the operating range established during the performance test.b. Reestablish the carbon bed temperature to the levels established during the performance test within 15 minutes of...

  4. 40 CFR Table 4 to Subpart Xxxx of... - Operating Limits for Puncture Sealant Application Control Devices

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... established during the performance test. 2. Carbon adsorber (regenerative) to which puncture sealant... carbon bed temperature at the operating range established during the performance test.b. Reestablish the carbon bed temperature to the levels established during the performance test within 15 minutes of...

  5. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... depressions (faults in the enamel) in the biting surfaces of teeth to prevent cavities. (b)...

  6. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... depressions (faults in the enamel) in the biting surfaces of teeth to prevent cavities. (b)...

  7. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... depressions (faults in the enamel) in the biting surfaces of teeth to prevent cavities. (b)...

  8. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... depressions (faults in the enamel) in the biting surfaces of teeth to prevent cavities. (b)...

  9. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... depressions (faults in the enamel) in the biting surfaces of teeth to prevent cavities. (b)...

  10. Anti-Streptococcus mutans property of a chitosan: Containing resin sealant

    PubMed Central

    Rajabnia, Ramazan; Ghasempour, Maryam; Gharekhani, Samane; Gholamhoseinnia, Sepide; Soroorhomayoon, Sepide

    2016-01-01

    Objective: This study sought to assess the inhibitory effect of chitosan-containing sealants against Streptococcus mutans. Materials and Methods: The antibacterial activity of the resin sealant was evaluated by direct contact test following the addition of 0, 1, 2, 3, 4, and 5 wt% chitosan. At 3, 6, 9, 24 and 48 h, 1 and 3 months, 10 μl of the microbial suspension in contact with resin sealant was cultured to count the number of colonies. Data were analyzed by one-way one-way analysis of variance (ANOVA), repeated measures ANOVA, and Scheffe test. Results: The minimum inhibitory concentration of chitosan against S. mutans was 2 wt%. At 3 h, bacterial count in the presence of 2–5 wt% chitosan was significantly lower than that at 0 and 1 wt% (P < 0.05). However, this difference in bacterial count between 2 and 3 wt% chitosan and between 4 and 5 wt% chitosan was not significant. At 6 h, the difference in bacterial count between 3 and 4 wt% chitosan was not significant, whereas the remaining groups were significantly different in terms of bacterial count at this time (P < 0.05). At the remaining time points, significant differences were found between 2 wt% chitosan and higher concentrations (P < 0.05). Conclusion: Sealants containing 2–5 wt% chitosan show an antimicrobial property that is intensified by increasing the concentration of chitosan. PMID:27011933

  11. EVALUATING THE POTENTIAL EFFICACY OF AN ANTIMICROBIAL-CONTAINING SEALANT ON DUCT LINER AND GALVANIZED STEEL

    EPA Science Inventory

    The article gives results of an evaluation of the potential efficacy of an antimicrobial-containing sealant on fibrous-glass duct liner (FGDL) and galvanized steel (GS) as used in heating, ventilating, and air-conditioning (HVAC) systems. HVAC systems become dirty to various degr...

  12. possible role of soluble fibrin monomer complex after gastroenterological surgery

    PubMed Central

    Kochi, Masatoshi; Shimomura, Manabu; Hinoi, Takao; Egi, Hiroyuki; Tanabe, Kazuaki; Ishizaki, Yasuyo; Adachi, Tomohiro; Tashiro, Hirotaka; Ohdan, Hideki

    2017-01-01

    AIM To examine the role of soluble fibrin monomer complex (SFMC) in the prediction of hypercoagulable state after gastroenterological surgery. METHODS We collected data on the clinical risk factors and fibrin-related makers from patients who underwent gastroenterological surgery at Hiroshima University Hospital between April 1, 2014 and March 31, 2015. We investigated the clinical significance of SFMC, which is known to reflect the early plasmatic activation of coagulation, in the view of these fibrin related markers. RESULTS A total of 123 patients were included in the present study. There were no patients with symptomatic VTE. Thirty-five (28%) patients received postoperative anticoagulant therapy. In the multivariate analysis, a high SFMC level on POD 1 was independently associated with D-dimer elevation on POD 7 (OR = 4.31, 95%CI: 1.10-18.30, P = 0.03). The cutoff SFMC level was 3.8 μg/mL (AUC = 0.78, sensitivity, 63%, specificity, 89%). The D-dimer level on POD 7 was significantly reduced in high-SFMC patients who received anticoagulant therapy in comparison to high-SFMC patients who did not. CONCLUSION The SFMC on POD 1 strongly predicted the hypercoagulable state after gastroenterological surgery than the clinical risk factors and the other fibrin related markers.

  13. 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.

  14. Submillisecond Elastic Recoil Reveals Molecular Origins of Fibrin Fiber Mechanics

    PubMed Central

    Hudson, Nathan E.; Ding, Feng; Bucay, Igal; O’Brien, E. Timothy; Gorkun, Oleg V.; Superfine, Richard; Lord, Susan T.; Dokholyan, Nikolay V.; Falvo, Michael R.

    2013-01-01

    Fibrin fibers form the structural scaffold of blood clots. Thus, their mechanical properties are of central importance to understanding hemostasis and thrombotic disease. Recent studies have revealed that fibrin fibers are elastomeric despite their high degree of molecular ordering. These results have inspired a variety of molecular models for fibrin’s elasticity, ranging from reversible protein unfolding to rubber-like elasticity. An important property that has not been explored is the timescale of elastic recoil, a parameter that is critical for fibrin’s mechanical function and places a temporal constraint on molecular models of fiber elasticity. Using high-frame-rate imaging and atomic force microscopy-based nanomanipulation, we measured the recoil dynamics of individual fibrin fibers and found that the recoil was orders of magnitude faster than anticipated from models involving protein refolding. We also performed steered discrete molecular-dynamics simulations to investigate the molecular origins of the observed recoil. Our results point to the unstructured αC regions of the otherwise structured fibrin molecule as being responsible for the elastic recoil of the fibers. PMID:23790375

  15. Inhibition of enamel demineralization by buffering effect of S-PRG filler-containing dental sealant.

    PubMed

    Kaga, Masayuki; Kakuda, Shinichi; Ida, Yusuke; Toshima, Hirokazu; Hashimoto, Masanori; Endo, Kazuhiko; Sano, Hidehiko

    2014-02-01

    The buffering capacity and inhibitory effects on enamel demineralization of two commercially available dental sealants were evaluated in this study. The effects of filler particles were also examined. Disks of enamel and cured sealant materials of BeautiSealant (silica or S-PRG filler) or Teethmate F-1 were incubated in lactic acid solutions (pH 4.0) for 1-6 d. The pH changes and amounts of ions released in the solutions were assessed, and enamel surfaces were observed using a scanning electron microscope. The pH of the solution with BeautiSealant (S-PRG filler) was neutralized from pH 4.0 to pH 6.1 (after incubation for 1 d) and from pH 4.0 to pH 6.7 (after incubation for 6 d). In addition, no release of calcium ions was detected and the enamel surface was morphologically intact in scanning electron microscopy images. However, the pH of the solution with Teethmate F-1 remained below pH 4.0 during incubation from days 1 to 6. Calcium release was increased in solutions up to and after 6 d of incubation. Scanning electron microscopy images showed that the structures of hydroxyapatite rods were exposed at the specimen surfaces as a result of demineralization. Ions released from S-PRG filler-containing dental sealant rapidly buffered the lactic acid solution and inhibited enamel demineralization.

  16. Effect of enamel sealants on tooth bleaching and on the color stability of the result.

    PubMed

    Corcodel, N; Hassel, A J; Sen, S; Saure, D; Rammelsberg, P; Lux, C J; Zingler, S

    2017-04-01

    The purpose of this in vitro study was to evaluate the effect of enamel sealants on bleaching of natural teeth by use of 40 % hydrogen peroxide in a dental surgery. The color stability of the results from bleaching was, furthermore, determined 10 months after the bleaching procedure. In a standardized setting, four sealants (Pro Seal(®), Light Bond™ Sealant, Protecto(®), and Clinpro™ XT Varnish) were applied to and removed from human teeth in accordance with the manufacturer's instructions. Natural teeth served as medium; half of the teeth were sealed and the others served as controls. Hydrogen peroxide gel (40 %; Opalescence Boost; Ultradent Products, South Jordan, UT, USA) was used as bleaching agent. Color measurement was performed with a spectroradiometer (Photoresearch PR670) before the bleaching process (T1) and 24 h (T2) and 10 months (T3) after bleaching. The spectroradiometer results were expressed by use of the Commission Internationale de l'Éclairage (CIE) L*a*b* color notation. The L*, a*, and b* values of the sealed and the unsealed surfaces were not significantly different at any time during the study (p > 0.05), irrespective of the sealant used. Ten months after the bleaching process, mean L*, a*, and b* values were lower than at 1-day post-bleaching; the mean value of ΔE between 1-day post-bleaching and 10 months post-bleaching was 2.46 (±3.1). The results of the study suggest that the effectiveness of professional tooth whitening is not appreciably affected by the application of the four sealants tested.

  17. 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.

  18. Retention of a Flowable Composite Resin in Comparison to a Conventional Resin-Based Sealant: One-year Follow-up

    PubMed Central

    Jafarzadeh, M.; Malekafzali, B.; Tadayon, N.; Fallahi, S.

    2010-01-01

    Objective: Long-term retention of pit and fissure sealants is crucial for their success. This clinical study evaluated the retention rate of a flowable composite resin (Filtek Supreme XT Flowable Restorative) compared to a conventional resin-based sealant (Concise Light Cure White Sealant) over 12 months. Materials and Methods: Forty subjects aged 6 to 9 years were included in the study. Using a half-mouth design, a total of 80 first permanent molars were sealed with conventional fissure sealant on one side of the mouth and flowable composite on the contralateral side. Clinical evaluation was performed at 3, 6, and 12 months by a single blind examiner and the retention was classified as complete retention, partial loss, or total loss. Results: For both materials, there was no total loss of sealants over 12 months. Partial loss of both materials was observed in one sealant after 3 months. After 6 months, 36 teeth sealed with conventional fissure sealant were intact compared with 37 sealed with a flowable composite, and after 12 months, 33 teeth sealed with conventional fissure sealant were intact compared with 35 that were sealed with a flowable composite. There were no statistically significant difference (P>0.05) between the two materials regarding the retention rate at each follow-up period. Conclusion: As flowable composite resulted in comparable sealant retention rates, this material could be a good choice for fissure sealant. PMID:21998768

  19. Smart patch piezoceramic actuator issues

    NASA Technical Reports Server (NTRS)

    Griffin, Steven F.; Denoyer, Keith K.; Yost, Brad

    1993-01-01

    The Phillips Laboratory is undertaking the challenge of finding new and innovative ways to integrate sensing, actuation, and the supporting control and power electronics into a compact self-contained unit to provide vibration suppression for a host structure. This self-contained unit is commonly referred to as a smart patch. The interfaces to the smart patch will be limited to standard spacecraft power and possibly a communications line. The effort to develop a smart patch involves both contractual and inhouse programs which are currently focused on miniaturization of the electronics associated with vibrational control using piezoceramic sensors and actuators. This paper is comprised of two distinct parts. The first part examines issues associated with bonding piezoceramic actuators to a host structure. Experimental data from several specimens with varying flexural stiffness are compared to predictions from two piezoelectric/substructure coupling models, the Blocked Force Model and the Uniform Strain Model with Perfect Bonding. The second part of the paper highlights a demonstration article smart patch created using the insights gained from inhouse efforts at the Phillips Laboratory. This demonstration article has self contained electronics on the same order of size as the actuator powered by a voltage differential of approximately 32 volts. This voltage is provided by four rechargeable 8 volt batteries.

  20. Fibrin-Targeted Magnetic Resonance Imaging Allows In Vivo Quantification of Thrombus Fibrin Content and Identifies Thrombi Amenable for Thrombolysis

    PubMed Central

    Jenkins, Julia; Modarai, Bijan; Wiethoff, Andrea J.; Phinikaridou, Alkystis; Grover, Steven P.; Patel, Ashish S.; Schaeffter, Tobias; Smith, Alberto; Botnar, Rene M.

    2014-01-01

    Objective Deep venous thrombosis is a major health problem. Thrombolytic therapies are effective in recanalizing the veins and preventing post-thrombotic complications, but there is no consensus on selection criteria. The aim of this study was to investigate a fibrin-specific MRI contrast agent (EP-2104R) for the accurate quantification of thrombus’ fibrin content in vivo and for the identification of thrombus suitable for thrombolysis. Approach and Results Venous thrombosis was induced in the inferior vena cava of 8- to 10-week-old male BALB/C mice and MRI performed 2, 4, 7, 10, 14, and 21 days later. Eighteen mice were scanned at each time point pre and 2 hours post injection of EP-2104R (8.0 μmol/kg) with 12 mice at each time point used to correlate fibrin contrast uptake with thrombus’ histological stage and fibrin content. Six mice at each time point were immediately subjected to intravascular thrombolytic therapy (10 mg/kg of tissue-type plasminogen activator). Mice were imaged to assess response to lytic therapy 24 hours after thrombolytic treatment. Two mice at each time point were scanned post injection of 0.2 mmol/kg of Gd-DTPA (gadolinium with diethylenetriaminepentacetate, Magnevist, Schering AG, Berlin, Germany) for control purpose. Contrast uptake was correlated positively with the fibrin content of the thrombus measured by Western blotting (R2=0.889; P<0.001). Thrombus relaxation rate (R1) post contrast and the change in visualized thrombus size on late gadolinium enhancement inversion recovery MRI pre–EP-2104R and post–EP-2104R injection were the best predictors for successful thrombolysis (area under the curve, 0.989 [95% confidence interval, 0.97–1.00] and 0.994 [95% confidence interval, 0.98–1.00] respectively). Conclusions MRI with a fibrin-specific contrast agent accurately estimates thrombus fibrin content in vivo and identifies thrombi that are amenable for thrombolysis. PMID:24723557

  1. Elastic behavior and platelet retraction in low- and high-density fibrin gels.

    PubMed

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

    2015-01-06

    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.

  2. Comparative evaluation of absorbable hemostats: advantages of fibrin-based sheets.

    PubMed

    Krishnan, Lissy K; Mohanty, Mira; Umashankar, P R; Lal, Arthur Vijayan

    2004-11-01

    Bioactive hemostats and wound dressings consist of either inherently active materials or act as delivery vehicles which contain such materials. Fibrin is a natural hemostat and scaffold, guiding the direction of wound contraction and closure. In order to improve the ease of application of liquid fibrin glue, we have made a freeze-dried form of polymerized fibrin that supports hemostasis and wound healing. The bleeding from the middle ear artery of rabbits was found to be arrested instantaneously on application of fibrin sheets, even when the animal was heparinized systemically. As the fibrin sheet was found to be fragile, gelatin was incorporated to the sheet and thus the mechanical stability was improved without compromising the hemostatic effect. The efficacy of the fabricated fibrin and fibrin-gelatin sheets to seal traumatized rat liver was compared with commercially available hemostats, Abgel (cross-linked gelatin) and Surgicel (cross-linked cellulose). Tissue compatibility of all the hemostats was studied by analyzing the liver tissue 15 days after application. While the hemostatic effect was best with fibrin and fibrin-gelatin sheets, both Surgicel and Abgel were not capable of arresting the bleeding quickly. Gross analysis of tissue on the 15th day of application, visibly, Abgel was not only degraded but resulted in severe adhesions of internal organs and histologically capsule formation around the implant was evident. Though Surgicel was also seen as cream soft material on the site of application that joined two pieces of liver, there was no adhesion of other internal organs and histologically, immune reaction and foreign-body-type giant cells were present in large amounts. Fibrin was not found grossly on application site whereas fibrin-gelatin was seen as a small white spot. Granulation tissue formation and cell migration into the fibrin-based sheets were evident, and therefore, fibrin-based sheets are not only efficient hemostats but showed optimum

  3. 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

  4. Sonothrombolysis for intraocular fibrin formation in an animal model.

    PubMed

    Yamashita, Toshifumi; Ohtsuka, Hiroki; Arimura, Noboru; Sonoda, Shozo; Kato, Chihiro; Ushimaru, Kaneo; Hara, Naoko; Tachibana, Katsuro; Sakamoto, Taiji

    2009-11-01

    Vascular diseases such as diabetic retinopathy or retinal arterial occlusion are always associated with retinal and/or choroidal vasculopathy and intravascular thrombosis is commonly found. The ultrasound (US) therapy is a recently developed technique to accelerate fibrinolysis and it is being applied to some clinical fields. The present study was to observe the effects of extraocular US exposure on intraocular fibrin, which is a deteriorating factor in various ocular diseases. Tubes containing human blood (2 mL) in the following groups were irradiated with US; US alone, US with tissue plasminogen activator (tPA), tPA alone, and saline (control). Fibrinolysis was quantified by measuring D-dimer after 2h. In rat eyes, intracameral fibrin (fibrin formation in the anterior chamber of the eye) was induced by YAG-laser-induced iris bleeding. Then, eyes in the following groups were irradiated with US; US alone, subconjunctival tPA alone, US and subconjunctival tPA, control. Intracameral fibrin was scored on day 3 (3+ maximum to 0). The temperatures of rat eyes were measured by infrared thermography. Histologic evaluation was also performed. D-dimer was increased by US with statistical significance (p <0.05) or tPA (p <0.01). D-dimer in US with tPA group was significantly higher than either US alone or tPA alone group (p <0.01). In rat eyes, the average intracameral fibrin score on day 3 was 1.4 in control group and 1.2 in subconjunctival tPA alone group; however, it decreased significantly in the US alone group (0.75; p <0.05, vs. control), US and subconjunctival tPA group (0.71; p <0.01, vs. control). The temperature was less than 34 degrees C after US exposure. No histologic damage was observed. US irradiation from outside accelerated intracameral fibrinolysis without causing apparent tissue damage. This noninvasive method might have therapeutic value for intraocular fibrin.

  5. Experimental Study of the Aging and Self-Healing of Glass/Ceramic Sealant Used in SOFCs

    SciTech Connect

    Liu, Wenning N.; Sun, Xin; Koeppel, Brian J.; Khaleel, Mohammad A.

    2010-01-01

    High operating temperatures of solid oxide fuel cells (SOFCs) require that sealant must function at a high temperature between 600oC and 900oC and in the oxidizing and reducing environments of fuel and air. This paper describes tests to investigate the temporal evolution of the volume fraction of ceramic phases, the evolution of micro-damage, and the self-healing behavior of the glass ceramic sealant used in SOFCs. It was found that after the initial sintering process, further crystallization of the glass ceramic sealant does not stop, but slows down and reduces the residual glass content while boosting the ceramic crystalline content. Under the long-term operating environment, distinct fibrous and needle-like crystals in the amorphous phase disappeared, and smeared/diffused phase boundaries between the glass phase and ceramic phase were observed. Meanwhile, the micro-damage was induced by the cooling-down process from the operating temperature to the room temperature, which can potentially degrade the mechanical properties of the glass/ceramic sealant. The glass/ceramic sealant self-healed upon reheating to the SOFC operating temperature, which can restore the mechanical performance of the glass/ceramic sealant.

  6. Microtensile Bond Strength of Embrace Wetbond Hydrophilic Sealant in Different Moisture Contamination: An In-Vitro Study

    PubMed Central

    Panigrahi, Antarmayee; Srilatha, K. T.; Mohanty, Susant; Bhuyan, Sanat K; Bardhan, Debojyoti

    2015-01-01

    Aim Contamination of etched enamel with saliva has been shown to result in sealant failure. Recently, a hydrophilic sealant has been introduced. In absence of documented literature, this in vitro study was undertaken to ascertain the efficacy of Embrace Wet Bond without reduction of microtensile bond strength in the different moisture contamination. Materials and Methods A 5mm block of sealant were built over prepared occlusal surface of 40 non-carious therapeutically extracted third molars which were sectioned into 1mm thick stick and tested using Zwick micro tensile tester. Obtained data were subjected to descriptive analysis, one-way ANOVA and Scheffe’s post-hoc tests. Results Mean microtensile bond strength of Embrace sealant was not significantly lowered in different moisture contamination groups except Group 3 (air drying), which showed very highly significant (p<0.001) decrease in μTBS as compared to Group 1 (non-contaminated). Conclusion Mean μTBS of Embrace sealant remains largely unchanged even in presence of moisture. Owing to its hydrophilic property, this sealant can be a great help in cases where maintaining isolation is difficult. PMID:26393199

  7. PAH volatilization following application of coal-tar-based pavement sealant

    USGS Publications Warehouse

    Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

    2012-01-01

    Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, have recently been identified as a source of volatile PAHs to the atmosphere. We tracked the volatilization of PAHs for 1 year after application of a coal-tar-based pavement sealant by measuring gas-phase PAH concentrations above the pavement surface and solid-phase PAH concentrations in sealant scraped from the surface. Gas-phase concentrations at two heights (0.03 and 1.28 m) and wind speed were used to estimate volatilization flux. The sum of the concentrations of eight frequently detected PAHs (ΣPAH8) in the 0.03-m sample 1.6 h after application (297,000 ng m-3) was about 5000 times greater than that previously reported for the same height above unsealed parking lots (66 ng m-3). Flux at 1.6 h after application was estimated at 45,000 μg m-2 h-1 and decreased rapidly during the 45 days after application to 160 μg m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ΣPAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ΣPAH8 lost to the atmosphere on the basis of air sampling (2–3 g m-2) and adhered sealant sampling (6 g m-2) during the first 16 days after application, translating to a loss to the atmosphere of one-quarter to one-half of the PAHs in the sealcoat product. Combining the estimated mass of ΣPAH8 released to the atmosphere with a national-use estimate of coal-tar-based sealant suggests that PAH emissions from new coal-tar-based sealcoat applications each year (~1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.

  8. Tunable Patch Antennas Using Microelectromechanical Systems

    DTIC Science & Technology

    2011-05-11

    Tunable Microstrip Patch Antena Using RF MEMS Technology, IEEE Transactions on Antennas and Propagations, Vol. 55, Issue 4, April 2007, pp. 1193...capacitors co-fabricated in the same process. 15. SUBJECT TERMS Microstrip antennas, patch antennas, radio frequency microelectromechanical systems...resonant mode. Keywords: Microstrip antennas, patch antennas, radio frequency microelectromechanical systems, tunable circuits and devices 2

  9. OpenSSO Project Patches

    SciTech Connect

    NEBERGALL, CHRISTOPHER

    2009-06-08

    These are patches to Sun Microsystems open source OpenSSO project to fix various bugs and incorporate changes for Sandia and NNSA to use the product including fixes to improve OpenSSO's authentication and authorization abilities. These fixes will then by incorporated by Sun into their Sun Access Manager product, which is used by various DOE/NNSA plants and labs. Having Sun maintain these changes will relieve SNL and DOE from the cost of maintaining the changes themselves.

  10. Fibrin Targeted Block Copolymers for the Prevention of Postsurgical Adhesions

    PubMed Central

    Medley, John M.; Kaplan, Eugene; Oz, Helieh S.; Sundararaj, Sharath C.; Puleo, David A.; Dziubla, Thomas D.

    2015-01-01

    Despite advances in surgical methods, postsurgical adhesions (PSA) remain a significant clinical challenge affecting millions of patients each year. These permanent fibrous connections between tissues result from the bridging of wounded internal surfaces by an extended fibrin gel matrix (FGM). Adhesion formation is a result of a systems level convergence of wound healing pathways, complicating the design of materials that could inhibit their occurrence. In this study, a systematic approach that identifies key material properties required for functional performance optimization was used to design a new fibrin-targeted PSA prevention material. A series of multifunctional polymers with varied molecular architectures was synthesized to investigate the effect of changing polymer structural parameters on the ability to disrupt the formation of an extended FGM. Initial studies in a murine adhesion model demonstrated a statistically significant reduction in the degree of PSA formation, demonstrating the potential value of this systematic approach. PMID:21695779

  11. ε-(γ-Glutamyl)lysine in Fibrin: Lack of Crosslink Formation in Factor XIII Deficiency

    PubMed Central

    Pisano, J. J.; Finlayson, J. S.; Peyton, Marjorie P.; Nagai, Yumiko

    1971-01-01

    Fibrin clots formed in normal plasma contained about 6 mol of ε-(γ-glutamyl)lysine per mol of fibrin, whereas those formed in plasma from individuals with Factor XIII deficiency contained little or none of this crosslink (0.02-0.64 mol/mol of fibrin). Partial supplementation of the plasma with Factor XIII, at a single concentration tested, commensurately increased the number of crosslinks. PMID:5279517

  12. 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.

  13. Autologous fibrin glue with growth factors in reconstructive maxillofacial surgery.

    PubMed

    Thorn, J J; Sørensen, H; Weis-Fogh, U; Andersen, M

    2004-01-01

    The aim of this paper was to describe a method for the preparation of autologous fibrin glue with platelet growth factors and to report its use with particulate cancellous bone in reconstructive maxillofacial surgery. The fibrin glue is a two-component glue, where the one component is a concentrated fibrinogen solution with platelet growth factors and the other component is a thrombin solution. Both components were produced from the patients own blood, thus making the glue entirely autologous. The glue was prepared from platelet rich plasma separated from 200 ml of the patient's blood prior to the operation. The fibrinogen in the glue was precipitated from the platelet rich plasma by ethanol precipitation at low temperature and separated together with the platelets by centrifugation. Raising the temperature to 37 degrees C redissolved the precipitate. The thrombin solution in the glue was produced from prothrombin precipitated from 10 ml of the platelet rich plasma by lowering the pH and the ionic strength. The precipitate was separated by centrifugation and dissolved in a calcium ion solution. Increasing the pH to neutral value induced activation to thrombin. Preparation of the fibrin glue was performed in the blood bank within 60 to 90 min with the use of standard equipment. The outcome from 200 ml of blood was approximately 8 ml of fibrin glue: 6 ml fibrinogen to be coagulated with 2 ml of thrombin. The glue had a fibrinogen concentration of approximately 12 times the value in platelet rich plasma and the concentration of growth factors was approximately eight times the value in platelet rich plasma. We have used this glue successfully with particulate bone grafts for reconstructive purposes within the oral and maxillofacial field. It might as well be applied to other surgical areas. Whenever larger amount of the glue will be needed, a whole unit of blood may be taken from the patient, and the red cells re-transfused to the patient during or after the operation.

  14. [Application of fibrin glue in facial nerve repair].

    PubMed

    Wang, Qinying; Hua, Qingquan; Wang, Shenqing

    2007-06-01

    This animal experiment was aimed to apply fibrin in facial nerve repair and to quest for technical improvements in facial surgery. In each of 15 healthy large ear white rabbits, a unilateral 5 mm intratemporal facial nerve gap was created, the proximal and distal stumps were inserted into chitin tube, 1 ml autologous fibrin glue was applied around the anastomotic zone, and no suture was employed. At 3 months and 5 months after opertion, electrophysioligical study was performed. Compared with normal nerves, the regenerating nerves in both the chitin tube bridged group and the perineurium suture group had longer incubation period, lower amplitude, slower nerve-muscle conduction velocity at 3 months postoperatively. The differences were distinctly significant (P < 0.01). Although being decreased at 5 months after operation, the differences were still statistically significant (P < 0.05). There were no significant differences between the chitin tube bridged group and perineurium suture group at 3 months and 5 months, respectively. The study suggests that facial nerve repair using fibrin glue and chitin tube has the advantages of being easier,faster and more stable.

  15. Laparoscopic Incisional Hernia Repair With Fibrin Glue in Select Patients

    PubMed Central

    Stefano, Olmi; Luca, Saguatti; Claudio, Pagano; Giuseppe, Vittoria; Enrico, Croce

    2010-01-01

    Background and Objective: Laparoscopic treatment of incisional hernias can be performed using different types of fixation devices and prosthesis. We present a case series of 19 patients with incisional hernias with a diameter of <6cm, who underwent laparoscopic repair using Hi-tex dual-side mesh, positioned intraperitoneally, fixed to the abdominal wall by fibrin glue (Tissucol). Methods: Nineteen patients with incisional hernias <6cm in diameter were enrolled in this study and treated laparoscopically with Hi-tex and Tissucol. Surgical complications and patient outcomes were assessed with a clinical follow-up. Results: Laparoscopic repair of incisional hernias by using Hi-tex mesh affixed to the parietal wall with fibrin glue was feasible and easy in patients with parietal defects <6cm in diameter. Mean operating time was 30 minutes. Mean hospital stay was 1.5 days. Almost no postoperative pain, major surgical complications, seroma formation, relapses, or prosthesis infection occurred during a mean follow-up of 20 months. Conclusions: In select patients, Hi-tex mesh affixed using fibrin glue allows laparoscopic repair of incisional hernias with very good patient outcomes, especially in terms of postoperative pain and seroma formation. PMID:20932376

  16. "Patch"ing up our tumor signaling knowledge.

    PubMed

    Atwood, Scott X; Whitson, Ramon J; Oro, Anthony E

    2013-05-01

    The tumor suppressor Patched1 (Ptch1) possesses well-described roles in regulating sonic hedgehog (SHH) signaling in the skin and preventing the formation of basal cell carcinomas (BCCs). In this issue, Kang et al. extend their previous work to show that a naturally occurring allele of Ptch1 found in FVB mice promotes early squamous cell carcinoma (SCC) growth without aberrant activation of the SHH pathway. The study reveals new roles for Ptch1 that lie at the nexus between BCC and SCC formation.

  17. 21 CFR 864.7320 - Fibrinogen/fibrin degradation products assay.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... dissolution of the fibrin in a blood clot) and in monitoring therapy for disseminated intravascular coagulation (nonlocalized clotting in the blood vessels). (b) Classification. Class II (performance standards)....

  18. 21 CFR 864.7320 - Fibrinogen/fibrin degradation products assay.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... dissolution of the fibrin in a blood clot) and in monitoring therapy for disseminated intravascular coagulation (nonlocalized clotting in the blood vessels). (b) Classification. Class II (performance standards)....

  19. 21 CFR 864.7320 - Fibrinogen/fibrin degradation products assay.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... dissolution of the fibrin in a blood clot) and in monitoring therapy for disseminated intravascular coagulation (nonlocalized clotting in the blood vessels). (b) Classification. Class II (performance standards)....

  20. 21 CFR 864.7320 - Fibrinogen/fibrin degradation products assay.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... dissolution of the fibrin in a blood clot) and in monitoring therapy for disseminated intravascular coagulation (nonlocalized clotting in the blood vessels). (b) Classification. Class II (performance standards)....

  1. 21 CFR 864.7320 - Fibrinogen/fibrin degradation products assay.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... dissolution of the fibrin in a blood clot) and in monitoring therapy for disseminated intravascular coagulation (nonlocalized clotting in the blood vessels). (b) Classification. Class II (performance standards)....

  2. 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

  3. [Fibrin glue injection therapy with diluted thrombin for complicated postoperative fistulas following digestive surgery].

    PubMed

    Tono, Takeshi; Murakami, Masahiro; Ohtsuru, Minoru; Monden, Takushi

    2014-11-01

    Fibrin glue injection is used for treating postoperative digestive fistulas; however, this method is not always successful, especially in cases of complicated fistulas. Generally, the fibrin glue coagulates immediately after application before it reaches the end of the fistulas. Based on the results of an in vitro study of tensile strength and coagulation time, we utilized fibrin glue injection therapy with diluted thrombin solution (× 30) for treating refractory postoperative complicated fistulas in 23 cancer patients. In 20 of these patients, the fistulas were successfully closed after an average of 2.0 treatment cycles. This simple method of fibrin glue injection with diluted thrombin is useful for treating complicated postoperative digestive fistulas.

  4. Laser-welded fused silica substrates using a luminescent fresnoite-based sealant

    NASA Astrophysics Data System (ADS)

    de Pablos-Martin, A.; Benndorf, G.; Tismer, S.; Mittag, M.; Cismak, A.; Lorenz, M.; Grundmann, M.; Höche, Th.

    2016-06-01

    The laser welding of two fused silica substrates using a fresnoitic glass thin film as a sealant by irradiation with a ns laser is studied. Two different laser parameter sets were compared in terms of bond quality, which include two different laser beam trajectories: linear and wobble (circular) trajectory. The composition of the glass sealant changes with the course of the laser welding, incorporating silica from the substrates. After joining, the bonded samples were exposed to UV light and a very intense emission in the blue spectral range is observed by naked eye, which is due to the crystallization of the fresnoite glass upon the laser irradiation. EDX analysis confirms the crystallization of fresnoite, together with a great enrichment in silica. The formation of a eutectic between both is very plausible. Bond quality and bond strength were evaluated by scanning acoustic microscopy (SAM) and tensile test, which results in a tensile stress of 7 MPa.

  5. Use of asphalt emulsion sealants in disposal of uranium mill tailings

    SciTech Connect

    Hartley, J.N.; Freeman, H.D.; Elmore, M.R.

    1981-07-01

    Studies of asphalt emulsion sealants conducted by the Pacific Northwest Laboratory have demonstrated that the sealants are effective in containing radon within uranium tailings. The laboratory and field studies have further demonstrated that radon exhalation from uranium tailings piles can be reduced by greater than 99% to near background levels. Field tests at the tailings pile in Grand Junction, Colorado confirmed that an 8-cm admix seal containing 22 wt % asphalt could be effectively applied with a cold-mix paver. Other techniques were successfully tested, including a soil stabilizer and a hot, rubberized asphalt seal that was applied with a distributor truck. After the seals were applied and compacted, overburden was applied over the seal to protect the seal from ultraviolet degradation.

  6. The effects of tissue sealants, platelet gels, and growth factors on wound healing.

    PubMed

    Brissett, Anthony E; Hom, David B

    2003-08-01

    The improved understanding of wound healing has resulted in the rapid expansion of tissue adhesives, platelet gels, and the use of growth factors. Tissue sealants have been used to close incisions, seal and secure skin flaps, as well as promote hemostasis. Platelet gels have multiple uses that take advantage of their inherent clot-forming ability as well as their potential to release growth factors. Recombinant platelet-derived growth factor has been studied extensively for the treatment of chronic dermal ulcers and shows promise in enhancing wound care. This article will address some recent advancements related to the expanding use of tissue sealants and growth factors to enhance wound healing within the head and neck area.

  7. Patching. Restitching business portfolios in dynamic markets.

    PubMed

    Eisenhardt, K M; Brown, S L

    1999-01-01

    In turbulent markets, businesses and opportunities are constantly falling out of alignment. New technologies and emerging markets create fresh opportunities. Converging markets produce more. And of course, some markets fade. In this landscape of continuous flux, it's more important to build corporate-level strategic processes that enable dynamic repositioning than it is to build any particular defensible position. That's why smart corporate strategists use patching, a process of mapping and remapping business units to create a shifting mix of highly focused, tightly aligned businesses that can respond to changing market opportunities. Patching is not just another name for reorganizing; patchers have a distinctive mindset. Traditional managers see structure as stable; patching managers believe structure is inherently temporary. Traditional managers set corporate strategy first, but patching managers keep the organization focused on the right set of business opportunities and let strategy emerge from individual businesses. Although the focus of patching is flexibility, the process itself follows a pattern. Patching changes are usually small in scale and made frequently. Patching should be done quickly; the emphasis is on getting the patch about right and fixing problems later. Patches should have a test drive before they're formalized but then be tightly scripted after they've been announced. And patching won't work without the right infrastructure: modular business units, fine-grained and complete unit-level metrics, and companywide compensation parity. The authors illustrate how patching works and point out some common stumbling blocks.

  8. Analysis of Stub Loaded Microstrip Patch Antennas

    NASA Technical Reports Server (NTRS)

    Bailey, M. C.; Deshpande, M. D.

    1997-01-01

    A microstrip patch antenna fed by a coaxial probe and reactively loaded by a open circuited microstrip line has been used previously to produce circular polarization[ l] and also as a building block for a series fed microstrip patch array [2]. Rectangular and circular patch antennas loaded with a microstrip stub were previously analyzed using the generalized Thevenin theorem [2,3]. In the Thevenin theorem approach, the mutual coupling between the patch current and the surface current on the stub was not taken into account. Also, the Thevenin theorem approach neglects continuity of current at the patch-stub junction. The approach in this present paper includes the coupling between the patch and stub currents as well as continuity at the patch-stub junction.

  9. Comparative Evaluation of the Marginal Sealing Ability of two Commercially Available Pit and Fissure Sealants

    PubMed Central

    Moses, Joyson; Rangeeth, Bollam Nammalwar; Sivakumar, Subramanian

    2016-01-01

    Introduction The occlusal surfaces of the teeth usually have pits and fissures which provide a good environment for demineralization with minimal salivary access and make them caries prone. The success of pit and fissure sealing materials is highly dependent on the marginal sealing ability of the fissures. Aim The present study was carried out to evaluate and compare the marginal sealing ability of two commercially available pit and fissure sealants. Materials and Methods A total of 50 human premolar teeth were used in this invitro study. Group 1 included 25 teeth for application of Clinpro sealant and Group 2 included twenty 25 for application of Helioseal F sealant. Samples were stored in artificial saliva for 72 hours before thermocycling. The samples were immersed in 2% methylene blue solution for 24 hours. The sectioned samples were examined under an Optical Stereomicroscope and compared in terms of the extent of microleakage based on the amount of dye penetration between the sealant and tooth substance interface. The dye penetration scores in both the groups was statistically analysed using Chi square test and Mann Whitney Test. A p-value of less than 0.05 was considered to be statistically significant. Results It was seen that in Group 1, 12 samples (48%) had no dye penetration (Grade 0) while in Group 2, 6 samples (24%) demonstrated Grade 0 penetration. Group 2 had the most extensive dye penetration (Grade 3) in 8 of 25 samples (32%) (p=0.014). Conclusion On comparison of the microleakage scores of the groups, a statistically significant difference was found between the two groups; indicating a much better performance of Clinpro as compared to Helioseal F. PMID:27790568

  10. Characterization and the Pattern of Surfaces of Sealant with nano size Composite Materials

    NASA Astrophysics Data System (ADS)

    Quddos, A.; Samtio, N. H.; Syed, A. M.

    2013-06-01

    Nano composite sealant is low viscosity, room temperature cured, opaque and flowable nature. They have variety of uses such as potting, pressure sealant and shock resistant. Most important factor influencing use of fillers in polymer composites is their ability to effectively transfer the applied load in the matrix. The effective utilization of fillers in composites for structural applications depends strongly on the ability to disperse the nano fillers homogeneously in the matrix without damaging them. R-Belite supper epoxy adhesive (RBSEA) were formulated with different nano fillers (KCl, Al2O3, ZrO2, SiO2, ZrO2) at room temperature. The composite were prepared with the 0.02 to 0.10 weight ratios to promote the nucleation of the nanoparticles in the applied sealant. Two main problems which arise in improving the properties are poor dispersion of the fillers in the composite and weak bonding between nano fillers and the matrix. These problems are solved by mechanical and chemical means. It was observed that mechanical properties like tensile strength, elongation hardness etc and thermal properties were also improved with incorporation of nanofillers in the working applied polymer matrix. The dispersion of nano fillers in polymer matrix is studied by Scanning electron microscopy (SEM). The results confirm the presence of nanomaterial in RBSEA/fillers nanocomposites. SEM is also used to characterize the pattern of surfaces with nano size composite materials.

  11. Social Marketing Risk-Framing Approaches for Dental Sealants in Rural American Indian Children

    PubMed Central

    Champine, Dorothy; Hoyt, Dee; Lin, Lillian; Salois, Emily; Silvas, Sharon; Tail, Terri Weasel; Williams, Matthew

    2015-01-01

    Objective To compare three variants of a culturally-relevant and theoretically-based message to determine the most influential risk framing approach for improving intention to place dental sealants for preschool children. Design and Sample A convenience sample of adult, American Indian participants (n = 89) attending a community health fair were assigned to view a gain-framed, loss-framed, or mix-framed dental sealant message. Measurements We compared participant's scores on a 46-item survey to determine the relative effect of the frame assignment on seven indices of behavior change. Results The mean difference in participant's stage-of-change scores (x = 1.17, n = 89, sd = 1.90) demonstrated a significant improvement for all groups after watching the dental sealant message t(88) = 5.81, p < .0001, 95% CI [0.77 – 1.57]. Self-efficacy was the only construct for which we detected a statistically significant difference as a function of frame assignment. Overall, the mix-framed message resulted in the highest scores. The gain-framed message was the least influential on four constructs. This finding is in contrast to findings that gain-framed oral health messages are most influential (Gallagher & Updegraff, 2012; O'Keefe & Jensen, 2007). Conclusions Community advisory board members determined to use the mix-framed approach in an oral-health social marketing campaign with a rural, American Indian audience. PMID:26032902

  12. Wear of two pit and fissure sealants in contact with primary teeth

    PubMed Central

    Galo, Rodrigo; Contente, Marta Maria Martins Giamatei; Borsatto, Maria Cristina

    2014-01-01

    Objectives: Wear simulations may provide an indication of the clinical performance of pit-and-fissure sealants when associated with primary teeth as counterbody, restricting the involved variables. The aim of this study was to evaluate wear of dental materials used as pit-and-fissure sealants in contact with primary teeth. Materials and Methods: A resinous sealant (Fluroshield®) and a resin-modified glass ionomer cement (Vitremer®) were selected in a post-plate design, using as counterbody primary tooth pins (4 × 4 × 2 mm) at 3 and 10 N vertical load, 1 Hz frequency, 900 wear cycles in artificial saliva (n = 15). Attrition coefficient values were obtained and the material and primary tooth volumes were analyzed. Data were analyzed statistically by ANOVA and Duncan's test (P < 0.05). Results: Fluroshield® presented the highest attrition coefficient values for the 3 N but these values decreased significantly for the 10 N load. The means for volume loss (3 mm) of the different samples after the wear test were not statistically different for the materials. The volume loss values for the primary teeth were statistically different and there was an increase in volume loss with the increase of the load applied in the wear tests. Conclusions: Differences were also observed with regard to the surface deformation characteristics. The wear rates of primary tooth enamel vary according to the type of material and the load applied during mastication. PMID:24966777

  13. Polyethylene Glycol-Based Synthetic Hydrogel Sealant for Closing Vitrectomy Wounds: An In Vivo and Histological Study

    PubMed Central

    Hoshi, Sujin; Okamoto, Fumiki; Arai, Mikki; Hirose, Tatsuo; Fukuda, Shinichi; Sugiura, Yoshimi; Oshika, Tetsuro

    2016-01-01

    Purpose We conducted an in vivo study using Dutch pigmented rabbit eyes to test the usefulness of polyethylene glycol (PEG) sealant for the closure of sutureless sclerotomies in microincisional vitrectomy surgery (MIVS). Methods Three-port, 23-gauge vitrectomy was performed on rabbit eyes. After air leakage was confirmed by the application of 0.625% povidone–iodine at the sclerotomy site, PEG sealant was subconjunctivally injected using a 27-gauge needle through conjunctival incisions to cover the sclerotomy wounds, following which it was polymerized by the application of xenon light for 60 seconds. Ophthalmological examinations and intraocular pressure measurements were conducted the day before and 1, 3, 5, and 7 days after surgery. The eyes were enucleated for histological evaluation 7 days after surgery. Results PEG sealant was rapidly polymerized by the application of xenon light after subconjunctival injection, and it firmly sealed the sclerotomies without air leakage, as confirmed by povidone–iodine dropping, in all cases. Conjunctival and scleral wounds closed with PEG sealant were successfully attached and remained intact till the end of the follow-up period. There was no sign of postoperative hypotony or infection in any eye, and no adverse effects of PEG sealant were found. In histological examination, linear scar formation and eosinophilic staining of collagen fibers were observed at the sclerotomy sites, while the sclerotomy tunnels appeared tightly closed. Conclusions PEG sealant can be useful for the closure of sutureless 23-gauge vitrectomy incisions in rabbits. Translational Relevance The PEG sealant may become an effective option for closing vitrectomy incisions including pediatric cases. PMID:27226931

  14. Evaluation of retention of pit and fissure sealants placed with and without air abrasion pretreatment in 6-8 year old children – An in vivo study

    PubMed Central

    Goswami, Mridula

    2017-01-01

    Background The success of pit and fissure sealants is directly related to their retention. The purpose of this study was to assess and compare the retention of pit and fissure sealants placed using acid etch alone and a combination of air abrasion and acid etch techniques. Material and Methods 50 subjects aged 6-8 years were included in the study. Primary second molars and permanent first molars were sealed in all four quadrants using split mouth design. The right maxillary and mandibular molars (Group A) were treated by acid etching alone while the left maxillary and mandibular molars (Group B) were pretreated with air abrasion followed by acid etching before application of pit and fissure sealant. Retention of sealants was checked using Simonsen’s criteria of sealant retention after three and six months of sealant application. Results There was no significant difference in retention of sealants in Group A and Group B (p<0.05) after three and six months follow up. The difference in sealant retention in primary and permanent molars was not significant (p>0.05). Maxillary molars showed superior retention compared to mandibular molars, which was statistically significant at both three and six months (p<0.05). Conclusions Combining air abrasion pretreatment with subsequent acid etching did not result in statistically significant difference in sealant retention compared to acid etching alone in both primary and permanent molars after 3 and 6 months follow up. An additional air abrasion pretreatment step can be avoided in pediatric patients when placing sealants and the procedure can be completed faster with better behavior management using acid etching alone. Key words:Pit and fissure sealant, acid etching, air abrasion. PMID:28210438

  15. The activated partial thromboplastin time of diluted plasma: variability due to the method of fibrin detection.

    PubMed Central

    Johnstone, I B

    1984-01-01

    The purpose of this study was to determine the effects of the dilution of plasma (1/3 in saline) on the kinetics of fibrin generation in the activated partial thromboplastin time (APTT) assay. The diluted APTT is considered to increase the sensitivity of the APTT test however, studies in our laboratory using an electro-optical fibrin detection system failed to show significant differences in APTT values obtained with diluted and undiluted canine plasma. Seventeen plasmas, including plasmas moderately and markedly deficient in intrinsic factor activity were assayed in the undiluted and diluted APTT assay using two methods for fibrin endpoint detection; a visual "tilt-tube" technique and an electro-optical detection system. In the former technique the endpoint was the formation of a visible fibrin web or clot; in the latter procedure the end point was the first detection of a change in optical density of the plasma. Optical density changes during fibrin formation were also recorded ( thrombokinetograms ). The results indicated that the electro-optical fibrin detection system failed to identify a prolongation of the APTT as a result of 1/3 plasma dilution; a prolongation that was consistently observed with the visual fibrin detection technique. Plasma dilution however, did significantly reduce the rate of fibrin production as indicated by the thrombokinetogram profile. It was concluded that the dilution of plasma with saline, as has been used to increase the sensitivity of the APTT assay procedure, has little effect on the time of onset of fibrin formation in a given plasma. The major effect appears to be on the way in which fibrin forms in that the polymerization/crosslinkage events associated with macroscopic fibrin production are delayed. PMID:6722646

  16. Adaptation of prey and predators between patches.

    PubMed

    Wang, Wendi; Takeuchi, Yasuhiro

    2009-06-21

    Mathematical models are proposed to simulate migrations of prey and predators between patches. In the absence of predators, it is shown that the adaptation of prey leads to an ideal spatial distribution in the sense that the maximal capacity of each patch is achieved. With the introduction of co-adaptation of predators, it is proved that both prey and predators achieve ideal spatial distributions when the adaptations are weak. Further, it is shown that the adaptation of prey and predators increases the survival probability of predators from the extinction in both patches to the persistence in one patch. It is also demonstrated that there exists a pattern that prey and predators cooperate well through adaptations such that predators are permanent in every patch in the case that predators become extinct in each patch in the absence of adaptations. For strong adaptations, it is proved that the model admits periodic cycles and multiple stability transitions.

  17. Micro-leakage of a Fissure Sealant Cured Using Quartz-tungsten-halogen and Plasma Arc Light Curing Units

    PubMed Central

    Bahrololoomi, Zahra; Soleimani, Ali Asghar; Jafari, Najmeh; Varkesh, Bentolhoda

    2014-01-01

    Background and aims. Newer curing units such as plasma arc can polymerize the sealants in much shorter curing times. The aim of this study was to compare the effect of two different curing units on the micro-leakage of a fissure sealant material. Materials and methods. Sixty two extracted premolars without caries were randomly divided into two groups of 31 samples. Occlusal surfaces of all teeth were cleansed. Then, teeth surfaces were etched by 37% phosphoric acid. After rinsing and drying, occlusal surfaces of teeth were sealed by a fissure sealant. The sealant was then cured using either a halogen light curing unit or a plasma arc curing light. After sealing, the teeth were thermocycled for 500 cycles. The teeth were then sectioned and examined for micro-leakage. Statistical analyses were performed with Mann-Whitney test. Results. There was no significant difference between two groups regarding micro-leakage (P = 0.42). Conclusion. Results showed that there was no significant difference between two different curing units. Therefore, plasma arc unit might be a useful alternative for sealant polymerization. PMID:25587389

  18. Comparative study of fluoride released and recharged from conventional pit and fissure sealants versus surface prereacted glass ionomer technology

    PubMed Central

    Salmerón-Valdés, Elias Nahum; Scougall-Vilchis, Rogelio J; Alanis-Tavira, Jorge; Morales-Luckie, Raúl Alberto

    2016-01-01

    Context: The fluoride release of sealants in vitro shows a marked decrease. Giomers are distinguishable from manufactured resin-based sealants and contain prereacted glass-ionomer particles (PRG). Aims: To compare the amounts of fluoride released from the main pit and fissure of a resin-based sealant with that from a Giomer and to assess the abilities of the sealant and the Giomer to recharge when exposed to regular use of fluoride rinse. Materials and Methods: The readings for the fluoride concentration were carried out for 60 days using a fluoride ion-specific electrode. After this period, the samples were recharged using a fluoride mouth rinse. The amount of fluoride released after this recharge was determined for 5 days. The data were analyzed using Student's t- and analysis of variance tests. Results: In general, all materials presented higher fluoride release in the first 24 h; G1 and G4 showed a higher fluoride release in this period. On the other hand, G3 and G1 presented the most constant fluoride release until the 8th day, wherein all the sealants considerably decreased in the amount of fluoride released. Conclusion: G1 and G3 released higher concentrations of fluoride, although no significant differences were found. Giomers recharged in the first 24 h after polymerization presented an improved and sustained fluoride release. PMID:26957792

  19. Transcutaneous Drainage of Gel-Like Substance after Application of Hydrogel Dural Sealant: Report of Two Cases

    PubMed Central

    Siman, Homayoun; Techy, Fernando

    2015-01-01

    Study Design Case report. Objective Incidental durotomy (IDT) is a common complication of spinal surgery. The use of collagen matrix graft along with hydrogel dural sealant is a common method of IDT repair. With this method, there have been several reported cases of detrimental dural sealant expansion in the literature. One case study reported an expansion rate greater than 300%; many report neurologic damage. This article reports the clinical course of two patients who developed postoperative transcutaneous drainage of a gel-like substance after the use of a dural sealant, which is a previously unreported complication. Methods The clinical course and treatment outcome of two patients is presented. Results Both patients experienced postoperative transcutaneous drainage of a gel-like substance at the surgical site. Case one began draining this substance on postoperative day 14. This patient required no further intervention, and the drainage ended after 3 mL of a gel-like substance was expressed from his incision while in the clinic. Case two began draining the gel on postoperative day 16. This patient underwent two washout procedures and resolution of the drainage. No infection was ever detected. Conclusions To our knowledge, our patients are the first reported cases of transcutaneous drainage of expanded dural sealant. It is important to take into consideration the unexpected expansion of a dural sealant when using it for the repair of IDT. PMID:26835216

  20. Micro-leakage of a Fissure Sealant Cured Using Quartz-tungsten-halogen and Plasma Arc Light Curing Units.

    PubMed

    Bahrololoomi, Zahra; Soleimani, Ali Asghar; Jafari, Najmeh; Varkesh, Bentolhoda

    2014-01-01

    Background and aims. Newer curing units such as plasma arc can polymerize the sealants in much shorter curing times. The aim of this study was to compare the effect of two different curing units on the micro-leakage of a fissure sealant material. Materials and methods. Sixty two extracted premolars without caries were randomly divided into two groups of 31 samples. Occlusal surfaces of all teeth were cleansed. Then, teeth surfaces were etched by 37% phosphoric acid. After rinsing and drying, occlusal surfaces of teeth were sealed by a fissure sealant. The sealant was then cured using either a halogen light curing unit or a plasma arc curing light. After sealing, the teeth were thermocycled for 500 cycles. The teeth were then sectioned and examined for micro-leakage. Statistical analyses were performed with Mann-Whitney test. Results. There was no significant difference between two groups regarding micro-leakage (P = 0.42). Conclusion. Results showed that there was no significant difference between two different curing units. Therefore, plasma arc unit might be a useful alternative for sealant polymerization.

  1. Automatic segmentation and analysis of fibrin networks in 3D confocal microscopy images

    NASA Astrophysics Data System (ADS)

    Liu, Xiaomin; Mu, Jian; Machlus, Kellie R.; Wolberg, Alisa S.; Rosen, Elliot D.; Xu, Zhiliang; Alber, Mark S.; Chen, Danny Z.

    2012-02-01

    Fibrin networks are a major component of blood clots that provides structural support to the formation of growing clots. Abnormal fibrin networks that are too rigid or too unstable can promote cardiovascular problems and/or bleeding. However, current biological studies of fibrin networks rarely perform quantitative analysis of their structural properties (e.g., the density of branch points) due to the massive branching structures of the networks. In this paper, we present a new approach for segmenting and analyzing fibrin networks in 3D confocal microscopy images. We first identify the target fibrin network by applying the 3D region growing method with global thresholding. We then produce a one-voxel wide centerline for each fiber segment along which the branch points and other structural information of the network can be obtained. Branch points are identified by a novel approach based on the outer medial axis. Cells within the fibrin network are segmented by a new algorithm that combines cluster detection and surface reconstruction based on the α-shape approach. Our algorithm has been evaluated on computer phantom images of fibrin networks for identifying branch points. Experiments on z-stack images of different types of fibrin networks yielded results that are consistent with biological observations.

  2. Anti-fibrin antibody binding in valvular vegetations and kidney lesions during experimental endocarditis.

    PubMed

    Yokota, M; Basi, D L; Herzberg, M C; Meyer, M W

    2001-01-01

    In Streptococcus sanguinis (sanguis) induced experimental endocarditis, we sought evidence that the development of aortic valvular vegetation depends on the availability of fibrin. Endocarditis was induced in New Zealand white rabbits by catheter placement into the left ventricle and inoculation of the bacteria. Fibrin was localized in the developing vegetation with 99mTechnetium (Tc)-labeled anti-fibrin antibody one or three days later. When rabbit anti-fibrin antibody was given intravenously on day 1, the mass of aortic valvular vegetation was significantly reduced at day 3; infusion of non-specific rabbit IgG showed no effect. The 99mTc-labeled anti-fibrin antibody also labeled kidneys that showed macroscopic subcapsular hemorrhage. To learn if the deposition of fibrin in the kidneys was a consequence of endocarditis required a comparison of farm-bred and specific pathogen-free rabbits before and after the induction of endocarditis. Before induction, the kidneys of farm-bred rabbits were labeled, but specific pathogen-free rabbits were free of labeling and signs of macroscopic hemorrhage. After 3 days of endocarditis, kidneys of 10 of 14 specific pathogen-free rabbits labeled with 99mTc-labeled anti-fibrin antibody and showed hemorrhage. Kidney lesions were suggested to be a frequent sequellae of S. sanguinis infective endocarditis. For the first time, fibrin was shown to be required for the continued development of aortic valvular vegetations.

  3. Effect of microgravity, temperature, and concentration on fibrin and collagen assembly.

    PubMed

    Nunes, C R; Roedersheimer, M T; Simske, S J; Luttges, M W

    1995-08-01

    In purified form collagen and fibrin can be processed into gel-like matrices of interconnecting fibers. The microscopic structure of materials produced from these macromolecules is critical to their utility as biomaterials. Varying the conditions of the assembly environment allows for the production of a wide range of morphologies. In this study, changes in gravity, temperature, and concentration were examined. Contrary to protein crystal growth studies which indicate substantial increases in organization and size in microgravity, the gravitational environment had no repeatable effect on collagen and fibrin fiber diameters and matrix porosity. However, fibrin gels formed in microgravity appeared more homogeneous than ground samples. Changes in temperature and concentration of both protein and buffer had substantial effects on fiber diameters and material porosity for both collagen and fibrin. Temperature experiments were performed over the range 23.8 to 39 degrees C for fibrin and 22 to 33 degrees C for collagen. Thrombin concentration was varied from 0.02 to 0.10 units/ml for fibrin experiments and buffer concentration was varied by means of a dialysis membrane for collagen experiments. Consequently, the temperature and concentration controls developed for flight experiments are being considered for their potential in developing fibrin and collagen based materials with well-defined microscopic structures. The increased homogeneity of fibrin gels produced in microgravity suggests the possibility of using this environment for the production of optimal biomaterials.

  4. 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.

  5. Improvement of fibrin clot structure after factor VIII injection in haemophilia A patients treated on demand.

    PubMed

    Antovic, Aleksandra; Mikovic, Danijela; Elezovic, Ivo; Zabczyk, Michael; Hutenby, Kjell; Antovic, Jovan P

    2014-04-01

    Patients with haemophilia A have seriously impaired thrombin generation due to an inherited deficiency of factor (F)VIII, making them form unstable fibrin clots that are unable to maintain haemostasis. Data on fibrin structure in haemophilia patients remain limited. Fibrin permeability, assessed by a flow measurement technique, was investigated in plasma from 20 patients with severe haemophilia A treated on demand, before and 30 minutes after FVIII injection. The results were correlated with concentrations of fibrinogen, FVIII and thrombin-activatable fibrinolysis inhibitor (TAFI), and global haemostatic markers: endogenous thrombin potential (ETP) and overall haemostatic potential (OHP). Fibrin structure was visualised using scanning electron microscopy (SEM). The permeability coefficient Ks decreased significantly after FVIII treatment. Ks correlated significantly with FVIII levels and dosage, and with ETP, OHP and levels of TAFI. SEM images revealed irregular, porous fibrin clots composed of thick and short fibers before FVIII treatment. The clots had recovered after FVIII replacement almost to levels in control samples, revealing compact fibrin with smaller intrinsic pores. To the best of our knowledge, this is the first description of fibrin porosity and structure before and after FVIII treatment of selected haemophilia patients. It seems that thrombin generation is the main determinant of fibrin structure in haemophilic plasma.

  6. 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.

  7. 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

  8. Kinetic Model Facilitates Analysis of Fibrin Generation and Its Modulation by Clotting Factors: Implications for Hemostasis-Enhancing Therapies

    DTIC Science & Technology

    2014-01-01

    investigating its potential as a hemostatic agent in trauma and surgery.6,7 These applications necessitate a detailed understanding of fibrin ...facilitates analysis of fibrin generation and its modulation by clotting factors: implications for hemostasis-enhancing therapies† Alexander Y...ability of the suggested molecular mechanisms to account for fibrin generation and degradation kinetics in diverse, physiologically relevant in vitro

  9. Foil Patches Seal Small Vacuum Leaks

    NASA Technical Reports Server (NTRS)

    Spiegel, Kirk W.; Reed, David W.

    1995-01-01

    Report discloses technique to patch holes in nickel-alloy rocket-engine nozzle parts prior to vacuum brazing. Technique involves lightly spot-welding nickel foil 0.002 in. thick over hole patched, then spot-welding corrosion-resistant steel foil of same thickness over nickel foil. Once patches subject to pressure and temperature of vacuum brazing, nickel foil diffuses to bond with nickel-alloy nozzle, making vacuum-tight seal.

  10. Measurement and control of electrostatic patch potentials

    NASA Astrophysics Data System (ADS)

    Garrett, Joseph L.; Munday, Jeremy N.

    Electrostatic patch potentials hinder many precision measurements, particularly measurements of the Casimir force. Despite the improved force sensitivity achieved over the last decade, only recently have attempts been made to measure and quantify the effects of patch potentials. Here we present an analysis of patch potentials measured by Kelvin probe force microscopy (KPFM) and discuss methods to control these potentials (e.g. humidity, material choice, etc).

  11. Multi-Mode Broadband Patch Antenna

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R. (Inventor)

    2001-01-01

    A multi-mode broad band patch antenna is provided that allows for the same aperture to be used at independent frequencies such as reception at 19 GHz and transmission at 29 GHz. Furthermore, the multi-mode broadband patch antenna provides a ferroelectric film that allows for tuning capability of the multi-mode broadband patch antenna over a relatively large tuning range. The alternative use of a semiconductor substrate permits reduced control voltages since the semiconductor functions as a counter electrode.

  12. RF MEMS reconfigurable triangular patch antenna.

    SciTech Connect

    Nordquist, Christopher Daniel; Christodoulou, Christos George; Feldner, Lucas Matthew

    2005-01-01

    A Ka-band RF MEMS enabled frequency reconfigurable triangular microstrip patch antenna has been designed for monolithic integration with RF MEMS phase shifters to demonstrate a low-cost monolithic passive electronically scanned array (PESA). This paper introduces our first prototype reconfigurable triangular patch antenna currently in fabrication. The aperture coupled patch antenna is fabricated on a dual-layer quartz/alumina substrate using surface micromachining techniques.

  13. RF MEMS reconfigurable triangular patch antenna.

    SciTech Connect

    Christodoulou, Christos George; Nordquist, Christopher Daniel; Feldner, Lucas Matthew

    2005-07-01

    A Ka-band RF MEMS enabled frequency reconfigurable triangular microstrip patch antenna has been designed for monolithic integration with RF MEMS phase shifters to demonstrate a low-cost monolithic passive electronically scanned array (PESA). This paper introduces our first prototype reconfigurable triangular patch antenna currently in fabrication. The aperture coupled patch antenna is fabricated on a dual-layer quartz/alumina substrate using surface micromachining techniques.

  14. Patch definition in metapopulation analysis: a graph theory approach to solve the mega-patch problem.

    PubMed

    Cavanaugh, Kyle C; Siegel, David A; Raimondi, Peter T; Alberto, Filipe

    2014-02-01

    The manner in which patches are delineated in spatially realistic metapopulation models will influence the size, connectivity, and extinction and recolonization dynamics of those patches. Most commonly used patch-definition methods focus on identifying discrete, contiguous patches of habitat from a single temporal observation of species occurrence or from a model of habitat suitability. However, these approaches are not suitable for many metapopulation systems where entire patches may not be fully colonized at a given time. For these metapopulation systems, a single large patch of habitat may actually support multiple, interacting subpopulations. The interactions among these subpopulations will be ignored if the patch is treated as a single unit, a situation we term the "mega-patch problem." Mega-patches are characterized by variable intra-patch synchrony, artificially low inter-patch connectivity, and low extinction rates. One way to detect this problem is by using time series data to calculate demographic synchrony within mega-patches. We present a framework for identifying subpopulations in mega-patches using a combination of spatial autocorrelation and graph theory analyses. We apply our approach to southern California giant kelp (Macrocystis pyrifera) forests using a new, long-term (27 years), satellite-based data set of giant kelp canopy biomass. We define metapopulation patches using our method as well as several other commonly used patch delineation methodologies and examine the colonization and extinction dynamics of the metapopulation under each approach. We find that the relationships between patch characteristics such as area and connectivity and the demographic processes of colonizations and extinctions vary among the different patch-definition methods. Our spatial-analysis/graph-theoretic framework produces results that match theoretical expectations better than the other methods. This approach can be used to identify subpopulations in metapopulations

  15. [Glossodynia--indication for patch testing?].

    PubMed

    Bäurle, G; Schönberger, A

    1986-08-15

    100 patients suffering from glossodynia without pathologic changes of the oral mucosa and 16 patients with suspected allergic contact stomatitis underwent patch testing using standard patch test and dental materials. The results were compared with those of patients in dental occupations suffering from hand eczema. As there is no clinical relevance of allergens in patients with glossodynia, patch testing seems to be unnecessary. On the other hand, patch test results of patients with stomatitis and dentures often suggest a causal allergy. In most of those cases, this was confirmed by complete healing after changing the denture bases, whereas in glossodynia such replacements never brought about a convincing improvement of the symptoms.

  16. The "edge effect" with patch test materials.

    PubMed

    Fyad, A; Masmoudi, M L; Lachapelle, J M

    1987-03-01

    A positive "edge effect", i.e., the accumulation on the skin of a chemical solution (such as fluorescein 0.01% in a 50/50 water-ethanol solution) at the periphery of the patch test sites has been demonstrated. It occurs with different test materials (Finn Chamber; Silver Patch Test; Patch Test Chamber). Practical implications are discussed: this observation could be important when discussing results of laboratory investigations. In clinical practice, it could explain the occurrence of "ring-shaped" positive allergic patch test reactions to chemicals used in solution, i.e., Kathon CG or hydrocortisone.

  17. Collection of analytes from microneedle patches.

    PubMed

    Romanyuk, Andrey V; Zvezdin, Vasiliy N; Samant, Pradnya; Grenader, Mark I; Zemlyanova, Marina; Prausnitz, Mark R

    2014-11-04

    Clinical medicine and public health would benefit from simplified acquisition of biological samples from patients that can be easily obtained at point of care, in the field, and by patients themselves. Microneedle patches are designed to serve this need by collecting dermal interstitial fluid containing biomarkers without the dangers, pain, or expertise needed to collect blood. This study presents novel methods to collect biomarker analytes from microneedle patches for analysis by integration into conventional analytical laboratory microtubes and microplates. Microneedle patches were made out of cross-linked hydrogel composed of poly(methyl vinyl ether-alt-maleic acid) and poly(ethylene glycol) prepared by micromolding. Microneedle patches were shown to swell with water up to 50-fold in volume, depending on degree of polymer cross-linking, and to collect interstitial fluid from the skin of rats. To collect analytes from microneedle patches, the patches were mounted within the cap of microcentrifuge tubes or formed the top of V-bottom multiwell microplates, and fluid was collected in the bottom of the tubes under gentle centrifugation. In another method, microneedle patches were attached to form the bottom of multiwell microplates, thereby enabling in situ analysis. The simplicity of biological sample acquisition using microneedle patches coupled with the simplicity of analyte collection from microneedles patches integrated into conventional analytical equipment could broaden the reach of future screening, diagnosis, and monitoring of biomarkers in healthcare and environmental/workplace settings.

  18. 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

  19. 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.

  20. Two Holes in 'Wooly Patch'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The rock abrasion tool on NASA's Mars Exploration Rover Spirit ground two holes in a relatively soft rock called 'Wooly Patch' near the base of the 'Columbia Hills' inside Gusev Crater on Mars. This approximately true-color image from the panoramic camera was taken on sol 200 (July 25, 2004) and generated using the camera's 600-, 530-, and 480-nanometer filters. It shows the natural red and reddish-brown color of the rock. Scientists speculate that this relatively soft rock (compared to others analyzed by Spirit) may have been modified by water. Small cracks in the surface outside the drill holes may be the result of interactions with water-rich fluids.

  1. Platelet rich fibrin - a novel acumen into regenerative endodontic therapy

    PubMed Central

    Sharma, Krishna

    2014-01-01

    Research into regenerative dentistry has added impetus onto the field of molecular biology. It can be documented as a prototype shift in the therapeutic armamentarium for dental disease. Regenerative endodontic procedures are widely being added to the current armamentarium of pulp therapy procedures. The regenerative potential of platelets has been deliberated. A new family of platelet concentrates called the platelet rich fibrin (PRF) has been recently used by several investigators and has shown application in diverse disciplines of dentistry. This paper is intended to add light on the various prospects of PRF and clinical insights to regenerative endodontic therapy. PMID:24516822

  2. Platelet-rich fibrin application in dentistry: a literature review.

    PubMed

    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.

  3. 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

  4. Computational imaging analysis of fibrin matrices with the inclusion of erythrocytes from homozygous SS blood reveals agglomerated and amorphous structures.

    PubMed

    Averett, Rodney D; Norton, David G; Fan, Natalie K; Platt, Manu O

    2017-01-01

    Sickle cell disease is a single point mutation disease that is known to alter the coagulation system, leading to hypercoagulable plasma conditions. These hypercoagulable conditions can lead to complications in the vasculature, caused by fibrin clots that form undesirably. There is a need to understand the morphology and structure of fibrin clots from patients with sickle cell disease, as this could lead to further discovery of treatments and life-saving therapies. In this work, a computational imaging analysis method is presented to evaluate fibrin agglomeration in the presence of erythrocytes (RBCs) homozygous for the sickle cell mutation (SS). Numerical algorithms were used to determine agglomeration of fibrin fibers within a matrix with SS RBCs to test the hypothesis that fibrin matrices with the inclusion of SS RBCs possess a more agglomerated structure than native fibrin matrices with AA RBCs. The numerical results showed that fibrin structures with SS RBCs displayed an overall higher degree of agglomeration as compared to native fibrin structures. The computational algorithm was also used to evaluate fibrin fiber overlap (aggregation) and anisotropy (orientation) in normal fibrin matrices compared to fibrin matrices polymerized around SS RBCs; however, there was no statistical difference. Ultrasound measurements of stiffness revealed rigid RBCs in the case of samples derived from homozygous SS blood, and densely evolving matrices, when compared to normal fibrin with the inclusion of AA RBCs. An agglomeration model is suggested to quantify the fibrin aggregation/clustering near RBCs for both normal fibrin matrices and for the altered structures. The results of this work are important in the sense that the understanding of aggregation and morphology in fibrin clots with incorporation of RBCs from persons living with sickle cell anemia may elucidate the complexities of comorbidities and other disease complications.

  5. HotPatch Web Gateway: Statistical Analysis of Unusual Patches on Protein Surfaces

    DOE Data Explorer

    Pettit, Frank K.; Bowie, James U. [DOE-Molecular Biology Institute

    HotPatch finds unusual patches on the surface of proteins, and computes just how unusual they are (patch rareness), and how likely each patch is to be of functional importance (functional confidence (FC).) The statistical analysis is done by comparing your protein's surface against the surfaces of a large set of proteins whose functional sites are known. Optionally, HotPatch can also write a script that will display the patches on the structure, when the script is loaded into some common molecular visualization programs. HotPatch generates complete statistics (functional confidence and patch rareness) on the most significant patches on your protein. For each property you choose to analyze, you'll receive an email to which will be attached a PDB-format file in which atomic B-factors (temp. factors) are replaced by patch indices; and the PDB file's Header Remarks will give statistical scores and a PDB-format file in which atomic B-factors are replaced by the raw values of the property used for patch analysis (for example, hydrophobicity instead of hydrophobic patches). [Copied with edits from http://hotpatch.mbi.ucla.edu/

  6. Transdermal patches: history, development and pharmacology

    PubMed Central

    Pastore, Michael N; Kalia, Yogeshvar N; Horstmann, Michael; Roberts, Michael S

    2015-01-01

    Transdermal patches are now widely used as cosmetic, topical and transdermal delivery systems. These patches represent a key outcome from the growth in skin science, technology and expertise developed through trial and error, clinical observation and evidence-based studies that date back to the first existing human records. This review begins with the earliest topical therapies and traces topical delivery to the present-day transdermal patches, describing along the way the initial trials, devices and drug delivery systems that underpin current transdermal patches and their actives. This is followed by consideration of the evolution in the various patch designs and their limitations as well as requirements for actives to be used for transdermal delivery. The properties of and issues associated with the use of currently marketed products, such as variability, safety and regulatory aspects, are then described. The review concludes by examining future prospects for transdermal patches and drug delivery systems, such as the combination of active delivery systems with patches, minimally invasive microneedle patches and cutaneous solutions, including metered-dose systems. PMID:25560046

  7. Immunoisolation Patch System for Cellular Transplantation

    NASA Technical Reports Server (NTRS)

    Wang, Taylor G. (Inventor)

    2014-01-01

    An immunoisolation patch system, and particularly a patch system comprising multiple immunoisolation microcapsules, each encapsulating biological material such as cells for transplantation, which can be used in the prophylactic and therapeutic treatment of disease in large animals and humans without the need for immunosuppression.

  8. Formulation study of tea tree oil patches.

    PubMed

    Minghetti, Paola; Casiraghi, Antonella; Cilurzo, Francesco; Gambaro, Veniero; Montanari, Luisa

    2009-01-01

    The antimicrobial, antifungal and anti-inflammatory properties of tea tree oil (TTO), the essential oil of Melaleuca alternifolia are well documented. In order to optimize its therapeutic activity, TTO patches were designed. The aim of this work was the formulation of monolayer patches containing TTO. Moreover, the performance of oleic acid (OA) as a skin penetration enhancer in patches was evaluated. Terpinen-4-ol (T4OL), the main component of TTO, was the marker used to evaluate TTO skin permeability. The permeation study was performed through human epidermis by using Franz diffusion cells. Patches were prepared by using methacrylic copolymers, Eudragit E100 (EuE100) or Eudragit NE (EuNE), and a silicone resin, BioPSA7-4602 (Bio-PSA). TTO and OA contents were fixed at 10% w/w and 3% w/w, respectively. The patches were prepared by a casting method and characterised in terms of T4OL content and skin permeability. All the selected polymers were suitable as the main component of the patch matrix. Since the main critical issue in the use of TTO is related to its toxicity after absorption, the local administration of TTO can take advantage of the use of patches based on EuE100 because of the high retained amount and the low permeation of T4OL. In this matrix, OA slightly increased the T4OL retained amount, improving the efficacy and safety of TTO patches.

  9. Pit and Fissure Sealants in Young Adults: An Evaluation of Placement Time and Retention Rate Using Two Isolation Techniques.

    DTIC Science & Technology

    1983-01-01

    L AD-A139 429 PI AND FSSJR SEAANTS IN YOUNG ADULTS AN EVAUAON I7 D-AUN L OFPLACEMENT ME.U) AIR FORCE INST OF TECHWRIOHT-PATTERSON AFB OH B A MATIS...I ll l l ....1 , , .. .. . ... i TABLE XIV Sealant retention by tooth surface at twelve months ........................ 44 TABLE XV Sealant...cotton - 12- roll isolation and the placement time of an occIusal amalgam restoration using rubber dam isolation in contralater.. l teeth. Fifty-five

  10. Quality Assessment of Information About Pit and Fissure Sealants in Persian Websites in 2012

    PubMed Central

    Ghasemi, Leila

    2016-01-01

    Objectives: Despite the increasing use of Internet, there is no supervision over the accuracy and quality of the information provided in the web. To deal with this problem, health specialists should take part in planning, publishing and supervision of online health-related information. The aim of this study was to evaluate the quality of information related to pit and fissure sealants in Persian websites. Materials and Methods: In this cross-sectional study, Persian websites providing information about fissure sealants were found using Google search engine. The searched keywords according to the MeSH database were “patient education” and “fissure sealant”. After applying the exclusion criteria, 37 websites out of 500 initial links remained in the study. These websites were evaluated based on a researcher-made checklist. The validity and reliability of the checklist were evaluated and confirmed. Descriptive analysis was applied to report the results of our study using SPSS version 11.5. Results: The average score for the quality of information was 22.46 out of 38. The minimum scores were 16 and 30 and belonged to Pezeshkanemrooz.com and Asa85.blogfa.com , respectively. The results showed that 62.2% of the answers were scored 2–4 and 37.8% were scored 1; therefore, the overall quality of the published content was rated to be moderate for 62.2% and low for 37.8% of the websites. Conclusions: Overall, the quality of information related to fissure sealant provided in Persian websites was good; however, the information given was mostly incomplete and could be improved. The main problems were doubtful credibility and outdated information. PMID:27536329

  11. Performance of a conventional sealant and a flowable composite on minimally invasive prepared fissures.

    PubMed

    Francescut, Paola; Lussi, Adrian

    2006-01-01

    Three different fissure preparation procedures were tested and compared to the non-invasive approach using a conventional unfilled sealant and a flowable composite. Eighty permanent molars were selected and divided into 4 groups of 20 teeth each. All the teeth were split into 2 halves, and the exposed fissures were photographed under a microscope (35x) before and after being prepared using the following methods: (I) Er:YAG laser (KEY Laser, KaVo) 600 mJ pulse energy, 6 Hz; (II) diamond bur; (III) Er: YAG laser (KEY Laser, KaVo) 200 mJ pulse energy, 4 Hz; (IV) Control group: Powder jet cleaner (Prophyflex, KaVo, Germany). The pre-and postimages were superimposed in order to evaluate the amount of hard tissue removed. Ten teeth in each group were then acid etched and sealed with an unfilled sealant (Delton opaque, Dentsply), while the remaining 10 teeth were acid etched, primed and bonded (Prime & Bond NT, Dentsply) and sealed with a flowable composite (X-flow, DeTrey, Dentsply). Material penetration and microleakage were evaluated after thermocycling (5000 cycles) and staining with methylene blue 5%. ANOVA and Mann-Whitney tests were applied for statistical analysis. The laser 600 mJ and bur eliminated the greatest amount of hard tissue. The control teeth presented the least microleakage when sealed with Delton or X-flow. A correlation between material penetration and microleakage could not be statistically confirmed. Mechanical preparation prior to fissure sealing did not enhance the final performance of the sealant.

  12. Collector sealants and breathing. Final Report, 25 September 1978-31 December 1979

    SciTech Connect

    Mendelsohn, M A; Luck, R M; Yeoman, F A; Navish, Jr, F W

    1980-02-20

    The objectives of this program were: (1) to investigate the pertinent properties of a variety of possible sealants for solar collectors and identify the most promising candidates, and (2) to study the effect of breathing in flat-plate, thermal solar collector units. The study involved two types of sealants, Class PS which includes preformed seals or gaskets and Class SC which includes sealing compounds or caulks. It was the intent of the study to obtain data regarding initial properties of candidate elastomers from manufacturers and from the technical literature and to use those sources to provide data pertaining to endurance of these materials under environmental service conditions. Where necessary, these data were augmented by experimental measurements. Environmental stresses evaluated by these measurements included elevated temperatures, moisture, ultraviolet light, ozone and oxygen, and fungus. The second major area of the work involved a study of the effects of materials used and design on the durability of solar collectors. Factors such as design, fabrication, materials of construction, seals and sealing techniques and absorber plate coatings were observed on actual field units removed from service. Such phenomena as leakage, corrosion and formation of deposits on glazing and absorber plate were noted. An evaluation of the properties of several desiccants was made in order to providemeans to mitigate the deleterious effects of water on collector life. Adsorbents for organic degradation products of sealants were also investigated in order to protect the glazing and absorber plate from deposited coatings. Since adsorbents and desiccants in general tend to take up both water and organic decomposition products, relative affinities of a number of these agents for water and for organic compounds were determined . Results are presented in detail.

  13. 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.

  14. Aluminum adjuvants elicit fibrin-dependent extracellular traps in vivo

    PubMed Central

    Munks, Michael W.; McKee, Amy S.; MacLeod, Megan K.; Powell, Roger L.; Degen, Jay L.; Reisdorph, Nichole A.; Kappler, John W.

    2010-01-01

    It has been recognized for nearly 80 years that insoluble aluminum salts are good immunologic adjuvants and that they form long-lived nodules in vivo. Nodule formation has long been presumed to be central for adjuvant activity by providing an antigen depot, but the composition and function of these nodules is poorly understood. We show here that aluminum salt nodules formed within hours of injection and contained the clotting protein fibrinogen. Fibrinogen was critical for nodule formation and required processing to insoluble fibrin by thrombin. DNase treatment partially disrupted the nodules, and the nodules contained histone H3 and citrullinated H3, features consistent with extracellular traps. Although neutrophils were not essential for nodule formation, CD11b+ cells were implicated. Vaccination of fibrinogen-deficient mice resulted in normal CD4 T-cell and antibody responses and enhanced CD8 T-cell responses, indicating that nodules are not required for aluminum's adjuvant effect. Moreover, the ability of aluminum salts to retain antigen in the body, the well-known depot effect, was unaffected by the absence of nodules. We conclude that aluminum adjuvants form fibrin-dependent nodules in vivo, that these nodules have properties of extracellular traps, and the nodules are not required for aluminum salts to act as adjuvants. PMID:20876456

  15. Fibrin formation and dissolution in women receiving oral contraceptive drugs.

    PubMed

    Ball, A P; McKee, P A

    1977-04-01

    Factors affecting fibrin formation and dissolution were compared for 15 women taking combined oral contraceptives and 15 women using nonpharmacological methods of birth control. The two groups were matched for age, body weight, time of blood collection, and day in menstrual cycle; none of the women was receiving other drugs known to affect the blood coagulation or fibrinolytic parameters measured in this study. Fibrinogen concentrations tended to be higher in the experimental group; the degree of fibrinogen degradation, number of fibrin cross-links, and levels of factor XIII and plasminogen were the same for both group. There were significant reductions in antithrombin activity, the euglobulin lysis time, and fibrinolytic inhibitor level in women using oral contraceptives. An estrogen dose effect was suggested for fibrinogen concentration and the degree of antithrombin activity. The increased fibrinolytic activity and decreased fibrinolytic inhibitor levels are consistent with in vitro observations that antithrombin also inhibits plasmin activity. Thus while oral contraceptive-induced depression of antithrombin III could possibly predispose to thrombosis by diminishing the inhibition of the serine protease clotting factors, the concomitant decreased level of plasmin inhibition might balance the system by favoring thrombolysis as well as the digestion and inactivation of certain clotting factors by plasmin.

  16. On the diagnosis and management of neurocutaneous syndrome, a toxicity disorder from dental sealants.

    PubMed

    Amin, Omar M

    2004-09-01

    Neurocutaneous syndrome, a newly discovered toxicity disorder, is characterized by neurological sensations, pain, depleted energy, and memory loss as well as itchy cutaneous lesions that may invite various opportunistic infections. Components in the calcium hydroxide dental sealants Dycal, Life and Sealapex have been identified as sources of the observed symptoms. Sulfonamide and neurological toxicity issues are discussed, and three case histories are presented. Additional notes on zinc oxide, Fynal, IRM, and Sultan U/P sealers are also included. Diagnostic and management protocols at the Parasitology Center, Inc., are proposed.

  17. Patch scales in coastal ecosystems

    NASA Astrophysics Data System (ADS)

    Broitman, Bernardo R.

    Quantifying the spatial and temporal scales over which ecological processes are coupled to environmental variability is a major challenge for ecologists. Here, I assimilate patterns of oceanographic variability with ecological field studies in an attempt to quantify spatial and temporal scales of coupling. Using coastal time series of chlorophyll-a concentration from remote sensing, the first chapter examines the alongshore extent of coastal regions subject to similar temporal patterns of oceanographic variability in Western North America (WNA) and North-Central Chile (Chile). I found striking interhemispherical differences in the length of coastal sections under similar oceanographic regimes, with the Chile region showing longshore coherency over much smaller spatial scales (˜60 km) than on the coast of WNA (˜140 km). Through a spatial analysis of coastal orientation I suggest that the characteristic length scales may be traced to the geomorphologic character of the ocean margins. The second chapter examines spatial patterns of primary production through long-term means of coastal chlorophyll-a concentration and kelp (Macrocystis pyrifera) cover and explores their relationship with coastal geomorphology and sea surface temperature (SST). Spatial analyses showed a striking match in length scales around 180--250 km. Strong anticorrelations at small spatial lags and positive correlations at longer distances suggest little overlap between patches of kelp and coastal chlorophyll-a. In agreement with findings from the previous chapter, I found that coastal patches could be traced back to spatial patterns of coastal geomorphology. Through SST time series and long-term datasets of larval recruitment in Santa Cruz Island, California, the third chapter examines temporal patterns of oceanographic variability as determinants of ecological patterns. SST time series from sites experiencing low larval recruitment rates were dominated by strong temporal variability. These sites

  18. Surface plasmon resonance analysis of immobilized fibrinogen and fibrin and their interaction with thrombin and fibrinogen

    NASA Astrophysics Data System (ADS)

    Dyr, Jan E.; Jirouskova, Marketa; Rysava, Jitka; Tichy, Ivo; Tobiska, Petr; Slavik, Radan; Homola, Jiri; Suttnar, Jiri

    1999-01-01

    The exploitation of surface plasmon resonance optical sensor for the study of the interaction of immobilized fibrinogen and fibrin monomer with soluble fibrinogen and thrombin is reported. Soluble fibrinogen was mostly reversible, the bound thrombin could be inhibited by milimolar concentration of phenylmethylsulphonyl fluoride (PMSF). At lease three sets of different thrombin binding sites were found. There was a residual fraction of thrombin bound to washed fibrin (ogin) (to about a five to ten percent of fibron monomer units) suggesting that a known naturally occurring fibrinogen variant differing in the gamma chain was the target. Surface bound fibrinogen was converted by thrombin to fibrin monomer that interacted with fibrinogen in solution. At low fibrin monomer surface density the second layer was formed that contained about the same amount of protein as the first layer, at higher fibrin monomer concentration less than one molecule of fibrinogen per molecule of fibrin monomer was captured. Starting with surface-bound fibrinogen and alternating addition of thrombin and fibrinogen a fibrin network of predetermined composition, size, and arrangement could be formed.

  19. Thrombin bound to a fibrin clot confers angiogenic and haemostatic properties on endothelial progenitor cells.

    PubMed

    Smadja, David M; Basire, Agnès; Amelot, Aymeric; Conte, Aurélie; Bièche, Ivan; Le Bonniec, Bernard F; Aiach, Martine; Gaussem, Pascale

    2008-06-01

    Recent data suggest that endothelial progenitor cells (EPCs) are involved in recanalizing venous thrombi. We examined the impact of a fibrin network, and particularly of adsorbed thrombin, on EPCs derived from cord blood CD34(+) cells. Fibrin networks generated in microplates by adding CaCl(2) to platelet-depleted plasma retained adsorbed thrombin at the average concentration of 4.2 nM per well. EPCs expressed high levels of endothelial cell protein C receptor and thrombomodulin, allowing the generation of activated protein C on the fibrin matrix in the presence of exogenous human protein C. The fibrin matrix induced significant EPC proliferation and, when placed in the lower chamber of a Boyden device, strongly enhanced EPC migration. These effects were partly inhibited by hirudin by 41% and 66%, respectively), which suggests that fibrin-adsorbed thrombin interacts with EPCs via the thrombin receptor PAR-1. Finally, spontaneous lysis of the fibrin network, studied by measuring D-dimer release into the supernatant, was inhibited by EPCs but not by control mononuclear cells. Such an effect was associated with a 10-fold increase in plasminogen activator inhibitor-1 (PAI-1) secretion by EPCs cultivated in fibrin matrix. Overall, our data show that EPCs, in addition to their angiogenic potential, have both anticoagulant and antifibrinolytic properties. Thrombin may modulate these properties and contribute to thrombus recanalization by EPCs.

  20. Thrombin bound to a fibrin clot confers angiogenic and haemostatic properties on endothelial progenitor cells

    PubMed Central

    Smadja, David M; Basire, Agnès; Amelot, Aymeric; Conte, Aurélie; Bièche, Ivan; Le Bonniec, Bernard F; Aiach, Martine; Gaussem, Pascale

    2008-01-01

    Abstract Recent data suggest that endothelial progenitor cells (EPCs) are involved in recanalizing venous thrombi. We examined the impact of a fibrin network, and particularly of adsorbed thrombin, on EPCs derived from cord blood CD34+ cells. Fibrin networks generated in microplates by adding CaCl2 to platelet-depleted plasma retained adsorbed thrombin at the average concentration of 4.2 nM per well. EPCs expressed high levels of endothelial cell protein C receptor and thrombomodulin, allowing the generation of activated protein C on the fibrin matrix in the presence of exogenous human protein C. The fibrin matrix induced significant EPC proliferation and, when placed in the lower chamber of a Boyden device, strongly enhanced EPC migration. These effects were partly inhibited by hirudin by 41% and 66%, respectively), which suggests that fibrin-adsorbed thrombin interacts with EPCs via the thrombin receptor PAR-1. Finally, spontaneous lysis of the fibrin network, studied by measuring D-dimer release into the supernatant, was inhibited by EPCs but not by control mononuclear cells. Such an effect was associated with a 10-fold increase in plasminogen activator inhibitor-1 (PAI-1) secretion by EPCs cultivated in fibrin matrix. Overall, our data show that EPCs, in addition to their angiogenic potential, have both anticoagulant and antifibrinolytic properties. Thrombin may modulate these properties and contribute to thrombus recanalization by EPCs. PMID:18494938

  1. Fibrinolysis inhibitors adversely affect remodeling of tissues sealed with fibrin glue.

    PubMed

    Krishnan, Lissy K; Vijayan Lal, Arthur; Uma Shankar, P R; Mohanty, Mira

    2003-01-01

    Experiments have been carried out to determine if aprotinin and epsilon -amino caproic acid increases the quality of Fibrin glue. A rat model was used for tissues such as liver and skin while rabbits were used for application of glue in dura mater. Apposition of all the tissues, glued with fibrin was found to be good and remnants of the polymerized fibrin were seen even on the seventh day of application, though inhibitors were not incorporated with the glue. In skin, excessive amounts of fibrin remained as a result of addition of aprotinin and epsilon -amino caproic acid, as compared to the glue applied without any inhibitor. After dural sealing, the wound repair and new bone formation at craniotomy site progressed well in the fibrin glue applied area as compared to the commercially available glue that contained aprotinin. The adhesive strength of the glue without or with fibrinolysis inhibitors was found to be similar, after 1h grafts on rat back. The observations from this study suggests that the use of aprotinin with fibrin glue may not be required because, even liver tissue that is known to have high fibrinolytic activity was sealed and repaired well in the absence of plasminogen inhibitors. On the other hand, it was found that if inhibitors were added, nondegraded matrix remained in the tissue even after 15 days and affected migration of repair cells. Thus, the inhibition of fibrinolysis after fibrin glue application is found detrimental to wound healing.

  2. Fibrin/platelet plug counteracts cutaneous wound contraction: the hypothesis of "skipping stone".

    PubMed

    Farahani, Ramin Mostofi Zadeh

    2007-01-01

    Cutaneous wound contraction and epithelialization act collaboratively to minimize the exposed wound surface. However excessive wound contraction is undesirable due to the resultant disfigurement and scarring. Fibrin clot has greater stiffness than surrounding tissue and mechanical strain further enhances its stiffness. On the contrary, skin exhibits diminished stiffness when affected by high strain rates. Therefore during early stages of wound healing, the contractile wound border is confronted by fibrin clot forming a high strain region in the interface of contractile tissue and fibrin clot--which is evidenced by computer simulation. Due to the stress relaxation property of skin, the contractile strain is partly neutralized. Meanwhile, gradually the stiffness of fibrin clot decreases which is followed by another cycle of wound contraction. This cyclic pattern of contraction resembles the movement of a stone over water or "skipping stone". The stone bounces repeatedly when thrown across the surface of water with reduction of jumping altitude with each bounce till the stone stops completely. This hypothesis is further supported by the observed initial delay in wound contraction and the chronological correlation of enhanced wound contraction with loss of superficial eschar and substitution of fibrin clot with granulation tissue. Also there is evidence that fibrin inhibits fibroblast-mediated contraction of collagen. Furthermore, modest increase in wound contraction rate in fibrinogen deficient mice and fibrin-mediated diminished wound contraction are agreement with the proposed hypothesis.

  3. Image Quality Assessment Based on Inter-Patch and Intra-Patch Similarity

    PubMed Central

    Zhou, Fei; Lu, Zongqing; Wang, Can; Sun, Wen; Xia, Shu-Tao; Liao, Qingmin

    2015-01-01

    In this paper, we propose a full-reference (FR) image quality assessment (IQA) scheme, which evaluates image fidelity from two aspects: the inter-patch similarity and the intra-patch similarity. The scheme is performed in a patch-wise fashion so that a quality map can be obtained. On one hand, we investigate the disparity between one image patch and its adjacent ones. This disparity is visually described by an inter-patch feature, where the hybrid effect of luminance masking and contrast masking is taken into account. The inter-patch similarity is further measured by modifying the normalized correlation coefficient (NCC). On the other hand, we also attach importance to the impact of image contents within one patch on the IQA problem. For the intra-patch feature, we consider image curvature as an important complement of image gradient. According to local image contents, the intra-patch similarity is measured by adaptively comparing image curvature and gradient. Besides, a nonlinear integration of the inter-patch and intra-patch similarity is presented to obtain an overall score of image quality. The experiments conducted on six publicly available image databases show that our scheme achieves better performance in comparison with several state-of-the-art schemes. PMID:25793282

  4. Fibronectin provides a conduit for fibroblast transmigration from collagenous stroma into fibrin clot provisional matrix.

    PubMed

    Greiling, D; Clark, R A

    1997-04-01

    After injury, the wound space is filled with a fibrin/fibronectin clot containing growth factors released by platelets and monocytes. In response to these factors, fibroblasts migrate into the fibrin clot and contribute to the formation of granulation tissue. The functional mechanisms allowing fibroblasts to leave the collagenous matrix of normal connective tissue and invade the provisional matrix of the fibrin clot have not been fully defined. To investigate these mechanisms we established a new in vitro model which simulates specific aspects of early wound healing, that is, the migration of fibroblasts from a three-dimensional collagen matrix into a fibrin clot. This transmigration could be induced by physiological concentrations of platelet releasate or platelet-derived growth factor BB (PDGF-BB) in a concentration-dependent manner. At 24 hours irradiated fibroblasts invaded the fibrin gel almost as well as non-irradiated cells, indicating that transmigration was independent of proliferation. Plasminogen and its activators appear to be necessary for invasion of the fibrin clot since protease inhibitors decreased the amount of migration. These serine proteases, however, were not necessary for exit from the collagen gel as fibroblasts migrated out of the collagen gel onto a surface coated with fibrin fibrils even in the presence of inhibitors. Removal of fibronectin (FN) from either the collagen gel or the fibrin gel markedly decreased the number of migrating cells, suggesting that FN provides a conduit for transmigration. Cell movement in the in vitro model was inhibited by RGD peptide, and by monoclonal antibodies against the subunits of the alpha5 beta1 and alpha v beta3 integrin receptor. Thus, the functional requirements for fibroblast transmigration from collagen-rich to fibrin-rich matrices, such as occurs in early wound healing, have been partially defined using an in vitro paradigm of this important biologic process.

  5. Abnormalities of pathways of fibrin turnover in lung lavage of rats with oleic acid and bleomycin-induced lung injury support alveolar fibrin deposition.

    PubMed Central

    Idell, S.; James, K. K.; Gillies, C.; Fair, D. S.; Thrall, R. S.

    1989-01-01

    Alveolar fibrin deposition commonly accompanies acute lung injury, but the nature of the local abnormalities of coagulation and fibrinolysis that support pathologic fibrin deposition are not well understood. The trended abnormalities of procoagulant and fibrinolytic activities occurring in lung lavage fluids of Fischer 344 rats after lung injury induced by intravenous oleic acid (OA) or intratracheal bleomycin were studied. After injury by either agent, bronchoalveolar lavage (BAL) contained increased procoagulant activity and decreased fibrinolytic activity. Lavage procoagulant activity was mainly due to an activator of Factor X attributable to the extrinsic coagulation pathway, and fibrinolytic activity was almost completely plasminogen dependent. Major mechanisms of inhibition of fibrinolytic activity involved both the inhibition of the plasminogen activator (PA) and plasmin. These abnormalities were temporally associated with prominent alveolar fibrin deposition in both models. In OA-treated animals, lavage fibrinolytic activity was absent or profoundly decreased, and antiplasmin and procoagulant activities were increased within 4 hours after the induction of acute lung injury. By 24 hours after OA, lavage PA inhibitor (PAI) activity was elevated with sustained antiplasmin activity. By 3 days after OA, these abnormalities had resolved in association with almost complete resolution of alveolar fibrin deposits. Within 3 days after bleomycin-induced lung injury, lavage procoagulant activity was increased and fibrinolytic activity was depressed due to increased antiplasmin and PAI activities. These conditions persisted for 2 weeks, during which time alveolar fibrin deposition was associated with the development of pulmonary fibrosis. These data indicate that a disruption of the normal balance between procoagulant and fibrinolytic activities occurs in alveolar lining fluids of rats with alveolitis induced by either OA or bleomycin, and that concurrent abnormalities

  6. RETICULOENDOTHELIAL CLEARANCE OF CIRCULATING FIBRIN IN THE PATHOGENESIS OF THE GENERALIZED SHWARTZMAN REACTION

    PubMed Central

    Lee, Leung

    1962-01-01

    Intravenous injections of endotoxin or infusions of thrombin in the rabbit initiate intravascular coagulation but do not usually result in massive deposition of fibrin. It has been proposed that the reticuloendothelial system may function efficiently in the removal of circulating fibrin; its blockade permits reproduction of all of the features of the generalized Shwartzman reaction by infusions of thrombin. In the rabbit the reticuloendothelial system may constitute the major protective mechanism against the vasculo-occlusive lesions of the generalized Shwartzman reaction, which appears to be the direct consequence of intravascular fibrin formation and deposition. PMID:14463528

  7. An ultrastructural analysis of platelets, erythrocytes, white blood cells, and fibrin network in systemic lupus erythematosus.

    PubMed

    Pretorius, Etheresia; du Plooy, Jenny; Soma, Prashilla; Gasparyan, Armen Yuri

    2014-07-01

    The study suggests that patients with systemic lupus erythematosus (SLE) present with distinct inflammatory ultrastructural changes such as platelets blebbing, generation of platelet-derived microparticles, spontaneous formation of massive fibrin network and fusion of the erythrocytes membranes. Lupoid platelets actively interact with other inflammatory cells, particularly with white blood cells (WBCs), and the massive fibrin network facilitates such an interaction. It is possible that the concerted actions of platelets, erythrocytes and WBC, caught in the inflammatory fibrin network, predispose to pro-thrombotic states in patients with SLE.

  8. Microporous nanofibrous fibrin-based scaffolds for craniofacial bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Osathanon, Thanaphum

    The fibrotic response of the body to synthetic polymers limits their success in tissue engineering and other applications. Though porous polymers have demonstrated improved healing, difficulty in controlling their pore sizes and pore interconnections has clouded the understanding of this phenomenon. In this study, a novel method to fabricate natural polymer/calcium phosphate composite scaffolds and immobilized alkaline phosphatase fibrin scaffolds with tightly controllable pore size, pore interconnection has been investigated. Microporous, nanofibrous fibrin scaffolds (FS) were fabricated using sphere-templating method. Calcium phosphate/fibrin composite scaffolds were created by solution deposition of calcium phosphate on fibrin surfaces or by direct incorporation of nanocrystalline hydroxyapatite (nHA). The SEM results showed that fibrin scaffolds exhibited a highly porous and interconnected structure. Osteoblast-like cells, obtained from murine calvaria, attached, spread and showed a polygonal morphology on the surface of the biomaterial. Multiple cell layers and fibrillar matrix deposition were observed. Moreover, cells seeded on mineralized fibrin scaffolds (MFS) exhibited significantly higher alkaline phosphatase activity as well as osteoblast marker gene expression compared to FS and nHA incorporated fibrin scaffolds (nHA/FS). These fibrin-based scaffolds were degraded both in vitro and in vivo. Furthermore, these scaffolds promoted bone formation in a mouse calvarial defect model and the bone formation was enhanced by addition of rhBMP-2. The second approach was to immobilize alkaline phosphatase (ALP) on fibrin scaffolds. ALP enzyme was covalently immobilized on the microporous nanofibrous fibrin scaffolds using 1-ethyl-3-(dimethylaminopropyl)carbodiimide hydrochloride (EDC). The SEM results demonstrated mineral deposition on immobilized ALP fibrin scaffolds (ALP/FS) when incubated in medium supplemented with beta-glycerophosphate, suggesting that the

  9. The Platelet Integrin αIIbβ3 Differentially Interacts with Fibrin Versus Fibrinogen.

    PubMed

    Litvinov, Rustem I; Farrell, David H; Weisel, John W; Bennett, Joel S

    2016-04-08

    Fibrinogen binding to the integrin αIIbβ3 mediates platelet aggregation and spreading on fibrinogen-coated surfaces. However,in vivoαIIbβ3 activation and fibrinogen conversion to fibrin occur simultaneously, although the relative contributions of fibrinogenversusfibrin to αIIbβ3-mediated platelet functions are unknown. Here, we compared the interaction of αIIbβ3 with fibrin and fibrinogen to explore their differential effects. A microscopic bead coated with fibrinogen or monomeric fibrin produced by treating the immobilized fibrinogen with thrombin was captured by a laser beam and repeatedly brought into contact with surface-attached purified αIIbβ3. When αIIbβ3-ligand complexes were detected, the rupture forces were measured and displayed as force histograms. Monomeric fibrin displayed a higher probability of interacting with αIIbβ3 and a greater binding strength. αIIbβ3-fibrin interactions were also less sensitive to inhibition by abciximab and eptifibatide. Both fibrinogen- and fibrin-αIIbβ3 interactions were partially inhibited by RGD peptides, suggesting the existence of common RGD-containing binding motifs. This assumption was supported using the fibrin variants αD97E or αD574E with mutated RGD motifs. Fibrin made from a fibrinogen γ'/γ' variant lacking the γC αIIbβ3-binding motif was more reactive with αIIbβ3 than the parent fibrinogen. These results demonstrate that fibrin is more reactive with αIIbβ3 than fibrinogen. Fibrin is also less sensitive to αIIbβ3 inhibitors, suggesting that fibrin and fibrinogen have distinct binding requirements. In particular, the maintenance of αIIbβ3 binding activity in the absence of the γC-dodecapeptide and the α-chain RGD sequences suggests that the αIIbβ3-binding sites in fibrin are not confined to its known γ-chain and RGD motifs.

  10. Fibrin glue prevents complications of septal surgery: findings in a series of 100 patients.

    PubMed

    Daneshrad, Payam; Chin, Gregory Y; Rice, Dale H

    2003-03-01

    Septal surgery is a common type of otolaryngology--head and neck surgery, and it is often performed in combination with other procedures. Complications of septal surgery include bleeding, hematoma, infection, abscess formation, and perforation. The most common methods of preventing these complications are the use of nasal packing, septal splints, and quilting sutures as a means of approximating the septal flaps. In this article, we describe our study of an alternate method: fibrin glue. We used fibrin glue as the sole method of approximating flaps on 100 consecutive septal surgery patients. Our results indicate that the use of fibrin glue is effective, rapid, comfortable, and inexpensive.

  11. Fibrin Glue Injection for Cavernous Sinus Hemostasis Associated with Cranial Nerve Deficit: A Case Report

    PubMed Central

    Tavanaiepour, Daryoush; Jernigan, Sarah; Abolfotoh, Mohamad; Al-Mefty, Ossama

    2015-01-01

    Fibrin glue injection has been used to control intraoperative cavernous sinus (CS) venous bleeding. There have been no reported complications related to this maneuver. We present a case where a patient developed a sensory trigeminal nerve deficit after injection of fibrin glue into the posterior CS during resection of a petrosal meningioma. We believe that this deficit was due to the compression of the trigeminal ganglion similar to balloon compression procedures. Although fibrin glue injection may achieve satisfactory cavernous sinus homeostasis, the volume and rate of injection should be kept in mind to avoid a compressive lesion on traversing cranial nerves and surrounding structures, or retrograde filling of the venous tributaries. PMID:26251815

  12. Patch shape, connectivity, and foraging by oldfield mice (Peromyscus polionotus).

    SciTech Connect

    Orrock, John, L.; Danielson, Brent J

    2005-06-01

    We examined how corridors and patch shape affect foraging by the oldfield mouse (Peromyscus polionotus) by deploying foraging trays and live traps in experimental landscapes with 3 different patch types: patches connected with a corridor, unconnected patches with projecting corridorlike portions (winged patches), and unconnected rectangular patches. Corridors did not lead to different levels of activity of P. polionotus among the 3 patch types. Rather, corridors influenced activity by changing patch shape: foraging in seed trays and total number of captures of P. polionotus tended to be greater at the patch center than at the patch edge, but only in connected and winged patches where corridors or wings increased the amount of patch edge relative to the amount of core habitat in the patch. P. polionotus avoided open microhabitats near the patch edge in winged and connected patches, but not open microhabitats near the patch interior, suggesting that predation risk caused shifts in foraging near edges in connected and winged patches. Foraging in corridors and wings was generally low, suggesting that both are high-risk habitats where predation risk is not ameliorated by proximity to vegetative cover. By changing patch shape, corridors caused changes in within-patch activity of P. polionotus, changing foraging patterns and potentially altering the dynamics of P. polionotus and the seeds they consume.

  13. Methods and preliminary findings of a cost-effectiveness study of glass-ionomer-based and composite resin sealant materials after 2 yr.

    PubMed

    Goldman, Ann S; Chen, Xi; Fan, Mingwen; Frencken, Jo E

    2014-06-01

    The cost-effectiveness of glass-carbomer, conventional high-viscosity glass-ionomer cement (HVGIC) [without or with heat (light-emitting diode (LED) thermocuring) application], and composite resin sealants were compared after 2 yr in function. Estimated net costs per sealant were obtained from data on personnel time (measured with activity sampling), transportation, materials, instruments and equipment, and restoration costs for replacing failed sealants from a community trial involving 7- to 9-yr-old Chinese children. Cost data were standardized to reflect the placement of 1,000 sealants per group. Outcomes were the differences in the number of dentine caries lesions that developed between groups. The average sealant application time ranged from 5.40 min (for composite resin) to 8.09 min (for LED thermocured HVGIC), and the average cost per sealant for 1,000 performed per group (simulation sample) ranged from $US3.73 (for composite resin) to $US7.50 (for glass-carbomer). The incremental cost-effectiveness of LED thermocured HVGIC to prevent one additional caries lesion per 1,000 sealants performed was $US1,106 compared with composite resin. Sensitivity analyses showed that differences in the cost of materials across groups had minimal impact on the overall cost. Cost and effectiveness data enhance policymakers' ability to address issues of availability, access, and compliance associated with poor oral-health outcomes, particularly when large numbers of children are excluded from care, in economies where oral health services are still developing.

  14. The polymerization and thrombin-binding properties of des-(B beta 1-42)-fibrin.

    PubMed

    Siebenlist, K R; DiOrio, J P; Budzynski, A Z; Mosesson, M W

    1990-10-25

    Multiple factors affect the thrombin-catalyzed conversion of fibrinogen to fibrin, including: fibrinopeptide (FPA and FPB) release leading to exposure of two types of polymerization domains ("A" and "B," respectively) in the central portion of the molecule, and exposure of a noncatalytic "secondary" thrombin-binding site in fibrin. Fibrinogen containing the FPA sequence but lacking the B beta 1-42 sequence ("des-(B beta 1-42)-fibrinogen"), was compared to native fibrinogen (containing both FPA and FPB) to investigate the role played by B beta 1-42 in the polymerization of alpha-fibrin (i.e. fibrin lacking FPA), to compare reptilase and thrombin cleavage of FPA from fibrinogen, and to explore the location and function of the secondary thrombin-binding site. Electron microscopy of evolving polymer structures (mu, 0.14; pH 7.4) plus turbidity measurements, showed that early thin fibril formation as well as subsequent lateral fibril associations were impaired in des-(B beta 1-42)-alpha-fibrin, thus indicating that the B beta 1-42 sequence contributes to the A polymerization site. Reptilase-activated des-(B beta 1-42)-alpha-fibrin polymerized even more slowly than thrombin-activated des-(B beta 1-42)-alpha-fibrin, differences that disappeared when repolymerization of preformed fibrin monomers was carried out. Since existing data indicate that thrombin releases FPA in a concerted manner, resulting in relatively rapid evolution of fully functional divalent alpha-fibrin monomers, it can be inferred that delayed fibrin assembly of reptilase fibrin is due to slower formation of divalent alpha-fibrin monomers. Thrombin-activated des-(B beta 1-42)-alpha-fibrin polymerized more rapidly at low ionic strength (mu, 0.04) than did native alpha,beta-fibrin, a reversal of their behavior at physiological ionic strength (mu, 0.14). Concomitant measurement of FPA release revealed modest slowing of release at low ionic strength from des-(B beta 1-42)-fibrinogen (t1/2, 36.5 versus 21

  15. An automated method for fibrin clot permeability assessment.

    PubMed

    Ząbczyk, Michał; Piłat, Adam; Awsiuk, Magdalena; Undas, Anetta

    2015-01-01

    The fibrin clot permeability coefficient (Ks) is a useful measure of porosity of the fibrin network, which is determined by a number of genetic and environmental factors. Currently available methods to evaluate Ks are time-consuming, require constant supervision and provide only one parameter. We present an automated method in which drops are weighed individually, buffer is dosed by the pump and well defined clot washing is controlled by the software. The presence of a straight association between drop mass and their dripping time allows to shorten the measurement time twice. In 40 healthy individuals, Ks, the number of drops required to reach the plateau (DTP), the time to achieve the plateau (TTP) and the DTP/TTP ratio (DTR) were calculated. There was a positive association between Ks (r = 0.69, P < 0.0001) evaluated by using the manual [median of 4.17 (3.60-5.18) ·10⁻⁹ cm²) and the automated method [median of 4.35 (3.74-5.38) ·10⁻⁹ cm²]. The correlation was stronger (r = 0.85, P < 0.001) in clots with DTP of 7 or less (n = 12). DTP was associated with total homocysteine (tHcy) (r = 0.35, P < 0.05) and activated partial thromboplastin time (APTT) (r = -0.34, P < 0.05), TTP with Ks (r = -0.55, P < 0.01 for the manual method and r = -0.44, P < 0.01 for the automated method) and DTP (r = 0.75, P < 0.0001), and DTR with Ks (r = 0.70, P < 0.0001 for the manual method and r = 0.76, P < 0.0001 for the automated method), fibrinogen (r = -0.58, P < 0.0001) and C-reactive protein (CRP) (r = -0.47, P < 0.01). The automated method might be a suitable tool for research and clinical use and may offer more additional parameters describing fibrin clot structure.

  16. Formulation and Characterization of Poloxamine-based Hydrogels as Tissue Sealants

    PubMed Central

    Cho, Eunhee; Lee, Jeoung Soo; Webb, Ken

    2012-01-01

    In-situ crosslinkable polyethylene glycol (PEG)-based polymers play an increasing role in surgical practice as sealants that provide a barrier to fluid/gas leakage and adhesion formation. This study investigated the gelation behavior and physical properties of hydrogels formed from homogeneous and blended solutions of two acrylated poloxamines (Tetronics® T1107 and T904) of varying molecular weight and hydrophilic/lipophilic balance relative to a PEG control. Hydrogels were formed by reverse thermal gelation at physiological temperature (T1107-containing formulations) and covalent crosslinking by Michael-type addition with dithiothreitol. All poloxamine-based hydrogels exhibited thermosensitive behavior and achieved significantly reduced swelling, increased tensile properties, and increased tissue bond strength relative to the PEG hydrogel at physiological temperature. Swelling and tensile properties of all poloxamine-based hydrogels were significantly greater at 37 °C relative to 4 °C, suggesting that their improved physical properties derive from cooperative crosslinking by both noncovalent and covalent mechanisms. Poloxamine-based hydrogels were cytocompatible and underwent hydrolytic degradation over 2 to 5 weeks depending on their T1107/T904 composition. In conclusion, select poloxamine-based hydrogels possess a number of properties potentially beneficial to tissue sealant applications including substantial increase in viscosity between room/physiological temperatures, resistance to cell adhesion, and maintenance of stable volume during equilibration. PMID:22406506

  17. Creep Behavior of Glass/Ceramic Sealant Used in Solid Oxide Fuel Cells

    SciTech Connect

    Liu, Wenning N.; Sun, Xin; Koeppel, Brian J.; Khaleel, Mohammad A.

    2010-01-02

    High operating temperature of solid oxide fuel cells require that sealant must function at high temperature between 600o and 900oC and in the oxidizing and reducing environments of fuel and air. It should be noted that creep deformation becomes relevant for a material when the operating temperature is near or exceeds half of its melting temperature (in degrees of Kelvin). The operating temperatures for most of the solid oxide fuel cells (SOFC) under development in the SECA program are around 800oC, which exceeds the glass transition temperature Tg for most glass ceramic materials. The goal of the study is to develop a creep model to capture the creep behavior of glass ceramic materials at high temperature and to investigate the effect of creep of glass ceramic sealant materials on stresses in glass seal and on the various interfaces of glass seal with other layers. The self-consistent creep models were incorporated into SOFC-MP and Mentat FC, and finite element analyses were performed to quantify the stresses in various parts. The stress in glass seals were released due to its creep behavior during the operating environments.

  18. Radon penetration of concrete slab cracks, joints, pipe penetrations, and sealants.

    PubMed

    Nielson, K K; Rogers, V C; Holt, R B; Pugh, T D; Grondzik, W A; de Meijer, R J

    1997-10-01

    Radon movement through 12 test slabs with different cracks, pipe penetrations, cold joints, masonry blocks, sealants, and tensile stresses characterized the importance of these anomalous structural domains. Diffusive and advective radon transport were measured with steady-state air pressure differences controlled throughout the deltaP = 0 to 60 Pa range. Diffusion coefficients (deltaP = 0) initially averaged 6.5 x 10(-8) m2 s(-1) among nine slabs with only 8% standard deviation, but increased due to drying by 0.16% per day over a 2-y period to an average of 2.0 x 10(-7) m2 s(-1). An asphalt coating reduced diffusion sixfold but an acrylic surface sealant had no effect. Diffusion was 42 times higher in solid masonry blocks than in concrete and was not affected by small cracks. Advective transport (deltaP < or = 60 Pa) was negligible for the slabs (10(-16) m2 permeability), pipe penetrations, and caulked gaps, but was significant for cracks, disturbed pipe penetrations, cold joints, masonry blocks, and concrete under tensile stress. Crack areas calculated to be as small as 10(-7) m2 significantly increased radon advection. Algebraic expressions predict air velocity and effective crack width from enhanced radon transport and air pressures. Masonry blocks, open cracks, and slab cold joints enhance radon penetration but stressed slabs, undisturbed pipe penetrations, and sealed cracks may not.

  19. Analysis of anticaries potential of pit and fissures sealants containing amorphous calcium phosphate using synchrotron microtomography.

    PubMed

    Delben, A C B; Cannon, M; Vieira, A E M; Basso, M D; Danelon, M; Santo, M R E; Stock, S R; Xiao, X; De Carlo, F

    2015-01-01

    The aim of this study was to analyze the anticaries potential of pit and fissure sealants containing amorphous calcium phosphate (ACP) by synchrotron microtomography. Bovine enamel blocks (4×4 mm; n=50) were selected through surface hardness (Knoop) analysis. Slabs were obtained through cross-sections taken 1 mm from the border of the enamel. Five indentations, spaced 100 μm apart, were made 300 μm from the border. Ten specimens were prepared for each tested material (Ultraseal XT plus TM, Aegis, Embrace, Vitremer and Experimental Sealant). The materials were randomly attached to the sectioned surfaces of the enamel blocks and fixed with sticky wax. The specimens were submitted to pH cycling. After that, the surface hardness (SH1) was determined, and the blocks were submitted to synchrotron microcomputed tomography analysis to calculate the mineral concentration (ΔgHAp cm(-3)) at different areas of the enamel. The comparison between the SH1 and ΔgHAp cm(-3) showed a correlation for all groups (r=0.840; p<0.001). The fluoride groups presented positive values of ΔgHAp cm(-3), indicating a mineral gain that was observed mainly in the outer part of the enamel. The ACP showed mineral loss in the outer enamel compared with fluoride groups, although it inhibited the demineralization in the deeper areas of enamel. The combination of two remineralizing agents (fluoride and ACP) was highly effective in preventing demineralization.

  20. Electrostatic patch potentials in Casimir force measurements

    NASA Astrophysics Data System (ADS)

    Garrett, Joseph; Somers, David; Munday, Jeremy

    2015-03-01

    Measurements of the Casimir force require the elimination of the electrostatic force between interacting surfaces. The force can be minimized by applying a potential to one of the two surfaces. However, electrostatic patch potentials remain and contribute an additional force which can obscure the Casimir force signal. We will discuss recent measurements of patch potentials made with Heterodyne Amplitude-Modulated Kelvin Probe Force Microscopy that suggest patches could be responsible for >1% of the signal in some Casimir force measurements, and thus make the distinction between different theoretical models of the Casimir force (e.g. a Drude-model or a plasma-model for the dielectric response) difficult to discern.

  1. Simplified Technique for Sealing Corneal Perforations Using a Fibrin Glue-Assisted Amniotic Membrane Transplant-Plug

    PubMed Central

    Kara, Selcuk; Arikan, Sedat; Ersan, Ismail

    2014-01-01

    Purpose. To describe a surgical technique using amniotic membrane transplant (AMT) with fibrin glue (FG) for treating smaller corneal perforations more practically and appropriately filling the defect. Method. A patient with noninfectious central corneal perforation, in 1 mm in diameter, was treated with FG-assisted AMT-plug. An AMT was folded in on itself twice by using FG then a small piece of this FG-AMT mixture was cut to maintain an appropriate plug for the site of the corneal perforation. The FG-assisted AMT-plug was placed in the perforation area by using FG. An amniotic membrane patch was placed over the plug, which was then secured by a bandage contact lens. Result. Surgery to restore corneal stromal thickness without recurrence of perforation. Conclusion. The FG-assisted AMT-plug allowed a successful repair of 1 mm in diameter corneal perforation. This technique was easily performed, thus seeming to be a good alternative to treat corneal perforations with restoring corneal thickness. PMID:25045563

  2. Efficacy of Light-Activated Sealant on Enamel Demineralization in Orthodontic Patients: An Atomic Force Microscope Evaluation

    PubMed Central

    Shinaishin, Suzi F; Ghobashy, Safaa A; EL-Bialy, Tarek H

    2011-01-01

    Objective: The purpose of this study was to investigate the efficacy of (Pro Seal) sealant in preventing enamel decalcification in-vivo and compare its effect with fluoride varnish and unfilled sealant using atomic force microscopy. Materials and Methods: Eight orthodontic patients who were candidates for extraction of all first premolars for orthodontic treatment were recruited to this study. Thirty two premolars (upper and lower) were randomly divided into four groups (n=8) for each group, 4 maxillary and 4 mandibular); Control (no -treatment); Fluoride varnish, Unfilled sealant (Light Bond) and filled sealant (Pro-Seal). After two months the brackets were debonded and the teeth were extracted and prepared for Atomic force microscopic scanning. Each sample was scanned twice at two different scan areas 50 and 10µm at the buccal cervical third of the crown. Images were recorded with slow scan rate and resolution and the mean roughness height and total surface area were calculated for each scan area. Comparison between groups was performed using one way analysis of variance test with level of significance was set to be 0.05. Results: Pro Seal treated samples show the lowest roughness height and total surface area. Conclusion: Pro Seal was the most effective prophylaxis technique in preventing enamel demineralization during orthodontic treatment. PMID:22207889

  3. In Vitro and In Vivo Evaluation of Commercially Available Fibrin Gel as a Carrier of Alendronate for Bone Tissue Engineering

    PubMed Central

    Kim, Beom Su; Shkembi, Feride

    2017-01-01

    Alendronate (ALN) is a bisphosphonate drug that is widely used for the treatment of osteoporosis. Furthermore, local delivery of ALN has the potential to improve the bone regeneration. This study was designed to investigate an ALN-containing fibrin (fibrin/ALN) gel and evaluate the effect of this gel on both in vitro cellular behavior using human mesenchymal stem cells (hMSCs) and in vivo bone regenerative capacity. Fibrin hydrogels were fabricated using various ALN concentrations (10−7–10−4 M) with fibrin glue and the morphology, mechanical properties, and ALN release kinetics were characterized. Proliferation and osteogenic differentiation of and cytotoxicity in fibrin/ALN gel-embedded hMSCs were examined. In vivo bone formation was evaluated using a rabbit calvarial defect model. The fabricated fibrin/ALN gel was transparent with Young's modulus of ~13 kPa, and these properties were not affected by ALN concentration. The in vitro studies showed sustained release of ALN from the fibrin gel and revealed that hMSCs cultured in fibrin/ALN gel showed significantly increased proliferation and osteogenic differentiation. In addition, microcomputed tomography and histological analysis revealed that the newly formed bone was significantly enhanced by implantation of fibrin/ALN gel in a calvarial defect model. These results suggest that fibrin/ALN has the potential to improve bone regeneration. PMID:28210623

  4. Mechanical Behavior of Collagen-Fibrin Co-Gels Reflects Transition From Series to Parallel Interactions With Increasing Collagen Content

    PubMed Central

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

    2013-01-01

    Fibrin and collagen, biopolymers occurring naturally in the body, are commonly-used biomaterials as scaffolds for tissue engineering. How collagen and fibrin interact to confer macroscopic mechanical properties in collagen-fibrin composite systems remains poorly understood. In this study, we formulated collagen-fibrin co-gels at different collagen-to-fibrin ratios to observe changes in overall mechanical behavior and microstructure. A modeling framework of a two-network system was developed by modifying our micro-scale model, considering two forms of interaction between the networks: (a) two interpenetrating but non-interacting networks (“parallel”), and (b) a single network consisting of randomly alternating collagen and fibrin fibrils (“series”). Mechanical testing of our gels show that collagen-fibrin co-gels exhibit intermediate properties (UTS, strain at failure, tangent modulus) compared to those of pure collagen and fibrin. Comparison with model predictions show that the parallel and series model cases provide upper and lower bounds respectively for the experimental data, suggesting that a combination of such interactions exist between collagen and fibrin in co-gels. A transition from the series model to the parallel model occurs with increasing collagen content, with the series model best describing predominantly fibrin co-gels, and the parallel model best describing predominantly collagen co-gels. PMID:22482659

  5. [Fibrin glue for operative correction of septal deviations].

    PubMed

    Boenisch, M; Nolst Trenité, G J

    2004-11-01

    The routine procedure after correction of septal deviations is the utilization of endonasal packing in order to avoid septal haematoma. However, the mechanical pressure of this packing damages the mucociliar activity of the mucosa and causes lymphoedema by blocking the lymphatic vessels. Besides it represents a foreign body within the nose causing pain and unpleasant feeling for the patient. In order to avoid these disadvantages, in 57 patients we used fibrin glue instead of nasal packing. After correction of the septal deviation the two mucoperichondrium blades where fixed together with Tissucol Duo Quick. This technique not only leads to haemostasis, but also provides fixation of the newly modeled septum. In only one patient we found a small unilateral septal haematoma, in all other cases the postoperative period showed no complications. Patients had a significant reduction of endonasal crusts and postoperative swelling. Patients comfort increased significant without the (standard) nasal packing.

  6. Immunobiology of Fibrin-Based Engineered Heart Tissue

    PubMed Central

    Conradi, Lenard; Schmidt, Stephanie; Neofytou, Evgenios; Deuse, Tobias; Peters, Laura; Eder, Alexandra; Hua, Xiaoqin; Hansen, Arne; Robbins, Robert C.; Beygui, Ramin E.; Reichenspurner, Hermann; Eschenhagen, Thomas

    2015-01-01

    Different tissue-engineering approaches have been developed to induce and promote cardiac regeneration; however, the impact of the immune system and its responses to the various scaffold components of the engineered grafts remains unclear. Fibrin-based engineered heart tissue (EHT) was generated from neonatal Lewis (Lew) rat heart cells and transplanted onto the left ventricular surface of three different rat strains: syngeneic Lew, allogeneic Brown Norway, and immunodeficient Rowett Nude rats. Interferon spot frequency assay results showed similar degrees of systemic immune activation in the syngeneic and allogeneic groups, whereas no systemic immune response was detectable in the immunodeficient group (p < .001 vs. syngeneic and allogeneic). Histological analysis revealed much higher local infiltration of CD3- and CD68-positive cells in syngeneic and allogeneic rats than in immunodeficient animals. Enzyme-linked immunospot and immunofluorescence experiments revealed matrix-directed TH1-based rejection in syngeneic recipients without collateral impairment of heart cell survival. Bioluminescence imaging was used for in vivo longitudinal monitoring of transplanted luciferase-positive EHT constructs. Survival was documented in syngeneic and immunodeficient recipients for a period of up to 110 days after transplant, whereas in the allogeneic setting, graft survival was limited to only 14 ± 1 days. EHT strategies using autologous cells are promising approaches for cardiac repair applications. Although fibrin-based scaffold components elicited an immune response in our studies, syngeneic cells carried in the EHT were relatively unaffected. Significance An initial insight into immunological consequences after transplantation of engineered heart tissue was gained through this study. Most important, this study was able to demonstrate cell survival despite rejection of matrix components. Generation of syngeneic human engineered heart tissue, possibly using human induced

  7. Scattering from arbitrarily shaped microstrip patch antennas

    NASA Technical Reports Server (NTRS)

    Shively, David G.; Deshpande, Manohar D.; Cockrell, Capers R.

    1992-01-01

    The scattering properties of arbitrarily shaped microstrip patch antennas are examined. The electric field integral equation for a current element on a grounded dielectric slab is developed for a rectangular geometry based on Galerkin's technique with subdomain rooftop basis functions. A shape function is introduced that allows a rectangular grid approximation to the arbitrarily shaped patch. The incident field on the patch is expressed as a function of incidence angle theta(i), phi(i). The resulting system of equations is then solved for the unknown current modes on the patch, and the electromagnetic scattering is calculated for a given angle. Comparisons are made with other calculated results as well as with measurements.

  8. Can Stem Cell 'Patch' Help Heart Failure?

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_164475.html Can Stem Cell 'Patch' Help Heart Failure? Small improvement seen over ... Scientists report another step in the use of stem cells to help treat people with debilitating heart failure. ...

  9. Axillary lymphadenectomy for breast cancer in elderly patients and fibrin glue

    PubMed Central

    2013-01-01

    Background Axillary lymphadenectomy or sentinel biopsy is integral part of breast cancer treatment, yet seroma formation occurs in 15-85% of cases. Among methods employed to reduce seroma magnitude and duration, fibrin glue has been proposed in numerous studies with controversial results. Methods Thirty patients over 60 years underwent quadrantectomy or mastectomy with level I/II axillary lymphadenectomy; a suction drain was fitted in all patients. Fibrin glue spray were applied to the axillary fossa in 15 patients; the other 15 patients were treated with harmonic scalpel. Results Suction drainage was removed between post-operative Days 3 and 4. Seroma magnitude and duration were not significant in patients receiving fibrin glue compared with the harmonic scalpel group. Conclusions Use of fibrin glue does not always prevent seroma formation, but can reduce seroma magnitude, duration and necessary evacuative punctures. PMID:24266959

  10. 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

  11. The effect of surface sealants with different filler content on microleakage of Class V resin composite restorations

    PubMed Central

    Hepdeniz, Ozge Kam; Temel, Ugur Burak; Ugurlu, Muhittin; Koskan, Ozgur

    2016-01-01

    Objective: Microleakage is still one of the most cited reasons for failure of resin composite restorations. Alternative methods to prevent microleakage have been investigated increasingly. The aim of this study is to evaluate the microleakage in Class V resin composite restorations with or without application of surface sealants with different filler content. Materials and Methods: Ninety-six cavities were prepared on the buccal and lingual surfaces with the coronal margins located in enamel and the cervical margins located in dentin. The cavities restored with an adhesive system (Clearfil SE Bond, Kuraray, Tokyo, Japan) and resin composite (Clearfil Majesty ES-2, Kuraray, Tokyo, Japan). Teeth were stored in distilled water for 24 h and separated into four groups according to the surface sealants (Control, Fortify, Fortify Plus, and G-Coat Plus). The teeth were thermocycled (500 cycles, 5–55° C), immersed in basic fuchsine, sectioned, and analyzed for dye penetration using stereomicroscope. The data were submitted to statistical analysis by Kruskal–Wallis and Bonferroni–Dunn test. Results: The results of the study indicated that there was minimum leakage at the enamel margins of all groups. Bonferroni–Dunn tests revealed that Fortify and GC-Coat groups showed significantly less leakage than the Control group and the Fortify Plus group at dentin margins in lingual surfaces (P < 0.05). Conclusion: The all surface sealants used in this study eliminated microleakage at enamel margins. Moreover, unfilled or nanofilled surface sealants were the most effective in decreasing the degree of marginal microleakage at dentin margins. However, viscosity and penetrability of the sealants could be considered for sealing ability besides composition. PMID:27095890

  12. Management of prosthetic patch infection after CEA.

    PubMed

    Naylor, Ross

    2016-04-01

    It has been reported that 0.5-1% of patients undergoing carotid endarterectomy with prosthetic patch closure of the arteriotomy will develop patch infection. One third occur within the first 2 months after surgery, while two-thirds occur after >6 months have elapsed. Wound infection and abscess formation is the commonest mode of presentation in early cases, while chronic sinus discharge and false aneurysm formation are the commonest presentations in late cases. The commonest infecting organisms are Staphylococci/Streptococci (90%) and this should be borne in mind when planning antibiotic therapy before cultures are available. Most patch infections present (semi)-electively and patch rupture is relatively rare (10%), thereby enabling the surgeon to undertake careful evaluation of the patients overall clinical and anatomical status, whilst planning the optimal treatment strategy. If necessary, the patient should be transferred to a tertiary center for treatment. This is not an operation to be undertaken by an inexperienced surgeon. Operative planning should involve checking the original operation note (did the patient tolerate carotid clamping under locoregional anesthesia and therefore might tolerate carotid ligation), is there evidence of contralateral cranial nerve lesions (a contraindication to major open surgery) and has the surgeon planned for adequate distal exposure of the internal carotid artery. Patch excision and autologous reconstruction (usually vein) is the current 'gold standard' treatment, but highly selected patients can be successfully treated by less invasive surgery (including insertion of a covered stent). Patch excision and prosthetic reconstruction should be avoided.

  13. Patch-clamp amplifiers on a chip.

    PubMed

    Weerakoon, Pujitha; Culurciello, Eugenio; Yang, Youshan; Santos-Sacchi, Joseph; Kindlmann, Peter J; Sigworth, Fred J

    2010-10-15

    We present the first, fully integrated, two-channel implementation of a patch-clamp measurement system. With this "PatchChip" two simultaneous whole-cell recordings can be obtained with rms noise of 8pA in a 10kHz bandwidth. The capacitance and series-resistance of the electrode can be compensated up to 10pF and 100MΩ respectively under computer control. Recordings of hERG and Na(v) 1.7 currents demonstrate the system's capabilities, which are on par with large, commercial patch-clamp instrumentation. By reducing patch-clamp amplifiers to a millimeter size micro-chip, this work paves the way to the realization of massively parallel, high-throughput patch-clamp systems for drug screening and ion-channel research. The PatchChip is implemented in a 0.5μm silicon-on-sapphire process; its size is 3×3mm(2) and the power consumption is 5mW per channel with a 3.3V power supply.

  14. Soluble fibrin degradation products potentiate tissue plasminogen activator-induced fibrinogen proteolysis.

    PubMed Central

    Weitz, J I; Leslie, B; Ginsberg, J

    1991-01-01

    Despite its affinity for fibrin, tissue plasminogen activator (t-PA) administration causes systemic fibrinogenolysis. To investigate the mechanism, t-PA was incubated with plasma in the presence or absence of a fibrin clot, and the extent of fibrinogenolysis was determined by measuring B beta 1-42. In the presence of fibrin, there is a 21-fold increase in B beta 1-42 levels. The potentiation of fibrinogenolysis in the presence of fibrin is mediated by soluble fibrin degradation products because (a) the extent of t-PA induced fibrinogenolysis and clot lysis are directly related, (b) once clot lysis has been initiated, fibrinogenolysis continues even after the clot is removed, and (c) lysates of cross-linked fibrin clots potentiate t-PA-mediated fibrinogenolysis. Fibrin degradation products stimulate fibrinogenolysis by binding t-PA and plasminogen because approximately 70% of the labeled material in the clot lysates binds to both t-PA- and plasminogen-Sepharose, and only the bound fractions have potentiating activity. The binding site for t-PA and plasminogen is on the E domain because characterization of the potentiating fragments using gel filtration followed by PAGE and immunoblotting indicates that the major species is (DD)E complex, whereas minor components include high-molecular weight derivatives containing the (DD)E complex and fragment E. In contrast, D-dimer is the predominant species found in the fractions that do not bind to the adsorbants, and it has no potentiating activity. Thus, soluble products of t-PA-induced lysis of cross-linked fibrin potentiate t-PA-mediated fibrinogenolysis by providing a surface for t-PA and plasminogen binding thereby promoting plasmin generation. The occurrence of this phenomenon after therapeutic thrombolysis may explain the limited clot selectivity of t-PA. Images PMID:1900308

  15. Fibrin containing gels induce angiogenesis. Implications for tumor stroma generation and wound healing.

    PubMed

    Dvorak, H F; Harvey, V S; Estrella, P; Brown, L F; McDonagh, J; Dvorak, A M

    1987-12-01

    Fibrin deposition is a consistent early event in solid tumors and healing wounds and precedes new blood vessel ingrowth in both. We now demonstrate that fibrin gels of themselves induce an angiogenic response in the absence of tumor cells or platelets. Angiogenesis was enhanced when certain chemoattractants or mitogens were included in the fibrin gel. Newly devised, inert plastic chambers with one porous surface were filled with varying contents and were implanted in the subcutaneous space of guinea pigs. Chambers filled with cross-linked homologous fibrin or plasma induced an angiogenic response within 4 days. Vessels entered chambers through the surface pores and flared out radially; angiogenesis was quantitated by point counting. Vessels were functional and matured along a gradient that proceeded from distal (least mature) to proximal. The intensity of the angiogenic response was enhanced when zymosan activated serum, an N-formylmethionine tripeptide, or platelet-derived growth factor was included in the fibrin matrix. Prior aldehyde fixation or boiling of fibrin-filled chambers inhibited angiogenesis, as did high concentrations of hyaluronic acid. Chambers filled with type I collagen or agarose did not induce new blood vessel formation, but addition of collagen did not reduce fibrin's capacity to initiate angiogenesis. The novel assay introduced here offers several advantages that should facilitate the study of angiogenesis. These include reproducibility, low background, objective and quantitative scoring, and the capacity to evaluate native molecules in animals of several species. Taken together, our findings strongly implicate fibrin or related proteins in the pathogenesis of angiogenesis and offer a new approach for elucidating the underlying molecular mechanisms.

  16. [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.

  17. Short-term monocular patching boosts the patched eye’s response in visual cortex

    PubMed Central

    Zhou, Jiawei; Baker, Daniel H.; Simard, Mathieu; Saint-Amour, Dave; Hess, Robert F.

    2015-01-01

    Abstract Purpose: Several recent studies have demonstrated that following short-term monocular deprivation in normal adults, the patched eye, rather than the unpatched eye, becomes stronger in subsequent binocular viewing. However, little is known about the site and nature of the underlying processes. In this study, we examine the underlying mechanisms by measuring steady-state visual evoked potentials (SSVEPs) as an index of the neural contrast response in early visual areas. Methods: The experiment consisted of three consecutive stages: a pre-patching EEG recording (14 minutes), a monocular patching stage (2.5 hours) and a post-patching EEG recording (14 minutes; started immediately after the removal of the patch). During the patching stage, a diffuser (transmits light but not pattern) was placed in front of one randomly selected eye. During the EEG recording stage, contrast response functions for each eye were measured. Results: The neural responses from the patched eye increased after the removal of the patch, whilst the responses from the unpatched eye remained the same. Such phenomena occurred under both monocular and dichoptic viewing conditions. Conclusions: We interpret this eye dominance plasticity in adult human visual cortex as homeostatic intrinsic plasticity regulated by an increase of contrast-gain in the patched eye. PMID:26410580

  18. Fibrin glue-infiltrating hemostasis for intractable bleeding from the liver or spleen during liver transplantation

    PubMed Central

    Jung, Dong-Hwan; Song, Gi-Won; Ha, Tae-Yong; Jwa, Eun-Kyeong; Lee, Sung-Gyu

    2016-01-01

    Portal hypertension induces congestion of the liver and spleen, thus any capsular or parenchymal injury to these organs can produce intractable bleeding which generally is not easily controlled. To cope with intractable bleeding such as being encountered during liver transplantation, we developed an infiltrating hemostasis technique as a conceptual shift from conventional application methods, in which fibrin glue is locally injected into the bleeding area on the liver or spleen. This technique, which uses a fibrin glue kit (2 ml kit; Greenplast, Green Cross, Seoul, Korea), consists of inserting the needle 0.5-1 cm deep at the bleeding point, forcefully injecting 1 ml of fibrin glue contained in the fibrin glue kit, and then slowly withdrawing the needle with continuous forceful injection of the remaining 1 ml of fibrin glue. We have successfully performed this procedure in 6 cases of living donor liver transplantation and in 2 cases of non-transplant resection of the cirrhotic livers with hepatocellular carcinoma. This technique was also successfully applied to one liver transplant recipient in which intractable bleeding occurred from a small laceration at the spleen. Our fibrin glue-infiltrating hemostasis would be indicated to intractable bleeding from the hepatic or splenic cut surface. In such a situation, it would be applicable as a second-line rescue method for hemostasis. PMID:28261700

  19. 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.

  20. Fibrin clot properties and haemostatic function in men and women with type 1 diabetes.

    PubMed

    Tehrani, Sara; Jörneskog, Gun; Ågren, Anna; Lins, Per-Eric; Wallén, Håkan; Antovic, Aleksandra

    2015-02-01

    The increased risk of vascular complications in type 1 diabetes may in part be explained by changes in haemostatic function. In the present study, we investigated the fibrin clot properties in patients with type 1 diabetes in relation to sex and microvascular complications. The study included 236 patients (107 women) aged between 20-70 years and without any history of cardiovascular disease. Fibrin clot properties, assessed by determination of the permeability coefficient (Ks) and turbidimetric clotting and lysis assays, did not differ between men and women. Compared with men, women had worse glycaemic control as well as higher levels of prothrombin fragment 1+2 and peak thrombin generation in vitro, indicating increased thrombin generation both in vivo and in vitro. Subgroup analyses of patients younger than 30 years revealed less permeable fibrin clots and prolonged lysis time in females compared with age-matched men. Patients with microvascular complications had higher fibrinogen concentrations and denser and less permeable fibrin clots. Thus, we conclude that in vitro fibrin clot properties in patients with type 1 diabetes without cardiovascular disease are not different between the sexes, but associate with prevalence of microvascular complications. Tighter fibrin clot formation in younger women, as suggested by our results, may affect their future cardiovascular risk and should be investigated in a larger population.

  1. 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.

  2. Induction therapy alters plasma fibrin clot properties in multiple myeloma patients: association with thromboembolic complications.

    PubMed

    Undas, Anetta; Zubkiewicz-Usnarska, Lidia; Helbig, Grzegorz; Woszczyk, Dariusz; Kozińska, Justyna; Dmoszyńska, Anna; Dębski, Jakub; Podolak-Dawidziak, Maria; Kuliczkowski, Kazimierz

    2015-09-01

    Induction therapy in patients with multiple myeloma increases the risk of thromboembolism. We have recently shown that multiple myeloma patients tend to form denser fibrin clots displaying poor lysability. We investigated the effect of induction therapy on fibrin clot properties in multiple myeloma patients. Ex-vivo plasma fibrin clot permeability, turbidity, susceptibility to lysis, thrombin generation, factor VIII and fibrinolytic proteins were compared in 48 multiple myeloma patients prior to and following 3 months of induction therapy, mainly with cyclophosphamide-thalidomide-dexamethasone regimen. Patients on thromboprophylaxis with aspirin or heparins were eligible. A 3-month induction therapy resulted in improved clot properties, that is higher clot permeability, compaction, shorter lag phase and higher final turbidity, along with shorter clot lysis time and higher rate of D-dimer release from fibrin clots than the baseline values. The therapy also resulted in lower thrombin generation, antiplasmin and thrombin-activatable fibrinolysis inhibitor (TAFI), but elevated factor VIII. Progressive disease was associated with lower posttreatment clot permeability and lysability. Despite thromboprophylaxis, two patients developed ischemic stroke and 10 had venous thromboembolism. They were characterized by pretreatment lower clot permeability, prolonged clot lysis time, longer lag phase, higher peak thrombin generation, TAFI and plasminogen activator inhibitor -1. Formation of denser plasma fibrin clots with reduced lysability and increased thrombin generation at baseline could predispose to thrombotic complications during induction treatment in multiple myeloma patients. We observed improved fibrin clot properties and thrombin generation in multiple myeloma patients except those with progressive disease.

  3. Platelet factor 4 (CXCL4) seals blood clots by altering the structure of fibrin.

    PubMed

    Amelot, Aymeric A; Tagzirt, Madjid; Ducouret, Guylaine; Kuen, René Lai; Le Bonniec, Bernard F

    2007-01-05

    Platelet factor-4 (PF4/CXCL4) is an orphan chemokine released in large quantities in the vicinity of growing blood clots. Coagulation of plasma supplemented with a matching amount of PF4 results in a translucent jelly-like clot. Saturating amounts of PF4 reduce the porosity of the fibrin network 4.4-fold and decrease the values of the elastic and loss moduli by 31- and 59-fold, respectively. PF4 alters neither the cleavage of fibrinogen by thrombin nor the cross-linking of protofibrils by activated factor XIII but binds to fibrin and dramatically transforms the structure of the ensuing network. Scanning electron microscopy showed that PF4 gives rise to a previously unreported pattern of polymerization where fibrin assembles to form a sealed network. The subunits constituting PF4 form a tetrahedron having at its corners a RPRH motif that mimics (in reverse orientation) the Gly-His-Arg-Pro-amide peptides that co-crystallize with fibrin. Molecular modeling showed that PF4 could be docked to fibrin with remarkable complementarities and absence of steric clashes, allowing the assembly of irregular polymers. Consistent with this hypothesis, as little as 50 microm the QVRPRHIT peptide derived from PF4 affects the polymerization of fibrin.

  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. Discovery of an uncovered region in fibrin clots and its clinical significance

    PubMed Central

    Hisada, Yohei; Yasunaga, Masahiro; Hanaoka, Shingo; Saijou, Shinji; Sugino, Takashi; Tsuji, Atsushi; Saga, Tsuneo; Tsumoto, Kouhei; Manabe, Shino; Kuroda, Jun-ichiro; Kuratsu, Jun-ichi; Matsumura, Yasuhiro

    2013-01-01

    Despite the pathological importance of fibrin clot formation, little is known about the structure of these clots because X-ray and nuclear magnetic resonance (NMR) analyses are not applicable to insoluble proteins. In contrast to previously reported anti-fibrin monoclonal antibodies (mAbs), our anti-fibrin clot mAb (clone 102–10) recognises an uncovered region that is exposed only when a fibrin clot forms. The epitope of the 102–10 mAb was mapped to a hydrophobic region on the Bβ chain that interacted closely with a counterpart region on the γ chain in a soluble state. New anti-Bβ and anti-γ mAbs specific to peptides lining the discovered region appeared to bind exclusively to fibrin clots. Furthermore, the radiolabelled 102–10 mAb selectively accumulated in mouse spontaneous tumours, and immunohistochemistry using this mAb revealed greater fibrin deposition in World Health Organization (WHO) grade 4 glioma than in lower-grade gliomas. Because erosive tumours are apt to cause micro-haemorrhages, even early asymptomatic tumours detected with a radiolabelled 102-10 mAb may be aggressively malignant. PMID:24008368

  6. Mesenchymal stem cell growth on and mechanical properties of fibrin-based biomimetic bone scaffolds.

    PubMed

    Linsley, Chase S; Wu, Benjamin M; Tawil, Bill

    2016-12-01

    Using the microenvironment of healing bone tissue as inspiration, this study utilized fibrin hydrogels combined with collagen type I and calcium phosphate ceramics to create a biomimetic bone scaffold. The contribution each component had on the growth of mesenchymal stem cells (hMSC) was assessed, and changes in the scaffold's mechanical properties were measured by indentation testing. The results show cell growth was greatest in scaffolds with lower concentrations of fibrinogen complex and followed a similar trend with the addition of collagen. However, cell growth was greatest in fibrin scaffolds with high concentrations of fibrinogen complex when combined with hydroxyapatite-β-tricalcium phosphate. The fibrin scaffold's stiffness does not significantly change over time, but the addition of collagen to scaffolds with low concentrations of fibrinogen complex had significant increases in stiffness by day 14. These results demonstrate that hMSC do not rapidly degrade fibrin and fibrin-collagen scaffolds in vitro. The data reported here can aid in the design and fabrication of fibrin-based engineered tissues and cell delivery vehicles that promote hMSC growth and viability as well as meet the mechanical requirements of native tissues. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2945-2953, 2016.

  7. Fibrin glue-infiltrating hemostasis for intractable bleeding from the liver or spleen during liver transplantation.

    PubMed

    Hwang, Shin; Jung, Dong-Hwan; Song, Gi-Won; Ha, Tae-Yong; Jwa, Eun-Kyeong; Lee, Sung-Gyu

    2016-11-01

    Portal hypertension induces congestion of the liver and spleen, thus any capsular or parenchymal injury to these organs can produce intractable bleeding which generally is not easily controlled. To cope with intractable bleeding such as being encountered during liver transplantation, we developed an infiltrating hemostasis technique as a conceptual shift from conventional application methods, in which fibrin glue is locally injected into the bleeding area on the liver or spleen. This technique, which uses a fibrin glue kit (2 ml kit; Greenplast, Green Cross, Seoul, Korea), consists of inserting the needle 0.5-1 cm deep at the bleeding point, forcefully injecting 1 ml of fibrin glue contained in the fibrin glue kit, and then slowly withdrawing the needle with continuous forceful injection of the remaining 1 ml of fibrin glue. We have successfully performed this procedure in 6 cases of living donor liver transplantation and in 2 cases of non-transplant resection of the cirrhotic livers with hepatocellular carcinoma. This technique was also successfully applied to one liver transplant recipient in which intractable bleeding occurred from a small laceration at the spleen. Our fibrin glue-infiltrating hemostasis would be indicated to intractable bleeding from the hepatic or splenic cut surface. In such a situation, it would be applicable as a second-line rescue method for hemostasis.

  8. Sciatic nerve regeneration using a nerve growth factor-containing fibrin glue membrane.

    PubMed

    Ma, Shengzhong; Peng, Changliang; Wu, Shiqing; Wu, Dongjin; Gao, Chunzheng

    2013-12-25

    Our previous findings confirmed that the nerve growth factor-containing fibrin glue membrane provides a good microenvironment for peripheral nerve regeneration; however, the precise mechanism remains unclear. p75 neurotrophin receptor (p75(NTR)) plays an important role in the regulation of peripheral nerve regeneration. We hypothesized that a nerve growth factor-containing fibrin glue membrane can promote neural regeneration by up-regulating p75(NTR) expression. In this study, we used a silicon nerve conduit to bridge a 15 mm-long sciatic nerve defect and injected a mixture of nerve growth factor and fibrin glue at the anastomotic site of the nerve conduit and the sciatic nerve. Through RT-PCR and western blot analysis, nerve growth factor-containing fibrin glue membrane significantly increased p75(NTR) mRNA and protein expression in the Schwann cells at the anastomotic site, in particular at 8 weeks after injection of the nerve growth factor/fibrin glue mixture. These results indicate that nerve growth factor-containing fibrin glue membrane can promote peripheral nerve regeneration by up-regulating p75(NTR) expression in Schwann cells.

  9. 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

    2016-09-06

    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.

  10. Fibrin gel as an injectable biodegradable scaffold and cell carrier for tissue engineering.

    PubMed

    Li, Yuting; Meng, Hao; Liu, Yuan; Lee, Bruce P

    2015-01-01

    Due to the increasing needs for organ transplantation and a universal shortage of donated tissues, tissue engineering emerges as a useful approach to engineer functional tissues. Although different synthetic materials have been used to fabricate tissue engineering scaffolds, they have many limitations such as the biocompatibility concerns, the inability to support cell attachment, and undesirable degradation rate. Fibrin gel, a biopolymeric material, provides numerous advantages over synthetic materials in functioning as a tissue engineering scaffold and a cell carrier. Fibrin gel exhibits excellent biocompatibility, promotes cell attachment, and can degrade in a controllable manner. Additionally, fibrin gel mimics the natural blood-clotting process and self-assembles into a polymer network. The ability for fibrin to cure in situ has been exploited to develop injectable scaffolds for the repair of damaged cardiac and cartilage tissues. Additionally, fibrin gel has been utilized as a cell carrier to protect cells from the forces during the application and cell delivery processes while enhancing the cell viability and tissue regeneration. Here, we review the recent advancement in developing fibrin-based biomaterials for the development of injectable tissue engineering scaffold and cell carriers.

  11. Caries detection methods: can they aid decision making for invasive sealant treatment?

    PubMed

    Pereira, A C; Verdonschot, E H; Huysmans, M C

    2001-01-01

    The decision to place sealants is a difficult one, and it has been suggested that in a low risk population it may be efficient to wait until caries is detected in the fissure. An invasive sealant technique with fissure preparation may then be indicated. The diagnostic method used in the indication of such a procedure should accurately detect both dentine caries and sound fissures: high sensitivity for dentine caries (at D3 threshold) with high specificity for enamel caries (at D1 threshold). The aims of this study were to assess the diagnostic performance of selected diagnostic methods at normal cut-offs for traditional dentine caries detection and at reduced cut-offs in relation to the desired performance mentioned above, and to assess whether fissure opening allows for accurate visual detection of dentinal caries. Data were obtained from 230 occlusal sites of 101 extracted human molar teeth. Diagnostic methods used on the entire sample were: visual inspection, electrical conductance measurements and laser fluorescence measurements. The sample was then divided into two groups. Group 1 was subjected to visual inspection after application of a dye. Group 2 was subjected to visual inspection after fissure opening only, and after subsequent dye application. Validation was performed by histological investigation. The results with cut-offs normally used in dentine caries detection were roughly in accordance with the literature, except for laser fluorescence. The sensitivity of visual inspection for dentinal caries (D3) was 17% before and 70% after fissure opening. Using reduced cut-offs, a 100% sensitivity (D3) was achieved with 2 methods, but this also resulted in 63 or 87% false positive diagnoses of sound surfaces. Visual inspection and electrical methods both showed a moderate to high sensitivity (D3) with a higher than 50% specificity (D1). It was concluded that visual inspection and electrical methods at reduced cut-offs may aid the indication of invasive sealant

  12. Self-etch bonding agent beneath sealant: Bond strength for laser-irradiated enamel

    PubMed Central

    Borsatto, Maria Cristina; Giuntini, Jackelline de Lemes; Contente, Marta Maria Martins Giamatei; Gomes-Silva, Jaciara Miranda; Torres, Carolina Paes; Galo, Rodrigo

    2013-01-01

    Objectives: This study evaluated the in vitro shear bond strength (SBS) of a resin-based pit-and-fissure sealant (Fluroshield [F], Dentsply/Caulk) associated with either an etch-and-rinse (Adper Single Bond 2 [SB], 3M/ESPE) or a two-step self-etch adhesive system (Adper SE Plus [SE], 3M/ESPE) on Er: YAG laser-irradiated enamel. Materials and Methods: Seventeen sound third molar crowns were embedded in acrylic resin, and the mesial–distal enamel surfaces were flattened. The enamel sites were irradiated with a 2.94-μm wavelength Er: YAG laser (120 mJ, 4 Hz, noncontact mode/17 mm, 20 s). The specimens were randomly assigned to three groups according to the bonding technique: I - 37% phosphoric acid etching + SB + F; II - SE + F and III - F applied to acid-etched enamel, without an intermediate layer of bonding agent. In all of the groups, a 3-mm diameter enamel-bonding site was demarcated and the sealant cylinders were bonded. After 24 hours in distilled water, the shear bond strength was tested at a crosshead speed of 0.5 mm/minute. The data were analyzed by one-way ANOVA and Tukey's test. The debonded specimens were examined with a stereomicroscope to assess the failure modes. Results: The mean SBS values in MPa were I = 6.39 (±1.44); II = 9.50 (±2.79); and III = 5.26 (±1.82). No statistically significant differences were observed between groups I and III; SE/F presented a significantly higher SBS than that of the other groups (P = 0.001). With regard to the failure mode, groups I (65%) and II (75%) presented adhesive failures, while group III showed 50% adhesive failure. Cohesive failure did not occur. Conclusion: The application of the two-step self-etch bonding agent (Adper SE Plus) beneath the resin pit-and-fissure sealant placement resulted in a significantly higher bond strength for the Er:YAG laser-irradiated enamel. PMID:24926208

  13. Platelet-rich fibrin (PRF): a second-generation platelet concentrate. Part I: technological concepts and evolution.

    PubMed

    Dohan, David M; Choukroun, Joseph; Diss, Antoine; Dohan, Steve L; Dohan, Anthony J J; Mouhyi, Jaafar; Gogly, Bruno

    2006-03-01

    Platelet-rich fibrin (PRF) belongs to a new generation of platelet concentrates geared to simplified preparation without biochemical blood handling. In this initial article, we describe the conceptual and technical evolution from fibrin glues to platelet concentrates. This retrospective analysis is necessary for the understanding of fibrin technologies and the evaluation of the biochemical properties of 3 generations of surgical additives, respectively fibrin adhesives, concentrated platelet-rich plasma (cPRP) and PRF. Indeed, the 3-dimensional fibrin architecture is deeply dependent on artificial clinical polymerization processes, such as massive bovine thrombin addition. Currently, the slow polymerization during PRF preparation seems to generate a fibrin network very similar to the natural one. Such a network leads to a more efficient cell migration and proliferation and thus cicatrization.

  14. Development of 400/sup 0/F sealants for flat plate solar collector construction and installation. Final report, 1 October 1978-30 September 1979

    SciTech Connect

    Morris, L.; Schubert, R.J.

    1980-03-01

    Twenty candidate sealants representing ten different polymer types were evaluated as potential solar collector sealants. Polymer types tested included epichlorohydrin rubber, EPDM rubber, silicone, polysulfide, acrylate rubber, and a fluoroelastomer. Initial screening of sealants consisted of measuring high temperature stability and adhesion retention. Several sealant compositions exhibited satisfactory performance in these tests and were selected for further evaluation. These materials were based on an EPDM rubber, a Viton fluoroelastomer, and silicone polymers. Further testing of these candidate materials included determination of adhesion retention under uv/water/heat conditions, fogging temperature, low temperature flexibility, and physical properties. Four silicone-based materials appeared to be suitable candidates for sealing solar collectors. These include Dow Corning 90-006-02 and 3120, General Electric 1200, and PR-1939 from Products Research and Chemical Corporation.

  15. Determinations of PCB within a project to develop cleanup methods for PCB-containing elastic sealant used in outdoor joints between concrete blocks in buildings.

    PubMed

    Sundahl, M; Sikander, E; Ek-Olausson, B; Hjorthage, A; Rosell, L; Tornevall, M

    1999-08-01

    Determinations of PCB were carried out as part of a project aimed at developing cleanup methods for PCB-containing elastic sealant used in outdoor joints between concrete blocks. The goals of the project were to develop methods, which minimise the spread of PCB to the outdoor environment and to indoor air, and which keep the PCB levels as low as reasonably possible in the workplace environment whilst removing the elastic sealant. The following PCB determinations were carried out: (1) concentration in the elastic sealant; (2) concentration in the concrete close to the sealant; (3) concentration in soil; (4) concentration in the indoor air; and (5) concentration in the air in the workplace environment. The cleanup process consisted of a number of different steps: (1) cutting the elastic sealant with an oscillating knife; (2) grinding the concrete with a mechanical machine; (3) sawing the concrete with a mechanical saw and (4) cutting the concrete with a mechanical chisel. In all these different steps a high capacity vacuum cleaner connected to the machines was used. The elastic sealant contained 4.7 to 8.1% total PCB of a technical product with a composition most similar to Clophene A40. The concrete close to the sealant (first 2 mm) contained 0.12 and 1.7% total PCB at two different places. The pattern of the PCB in the concrete resembled that of the sealant. PCB concentrations in the soil from the ground close to the building were 0.1 and 0.3 ppm at two different places before the remedial action. The source of the PCB in the soil is most likely the sealant as the PCB pattern is similar for the two materials. The PCB levels in the workplace air at the beginning of the project, when the techniques were not fully developed, were generally above the occupational exposure limit of 10 micrograms m-3 (up to 120 micrograms m-3). Later when the techniques were optimised to better take care of dust and gases produced during the cutting and grinding etc., the levels were

  16. Individual colour patches as multicomponent signals.

    PubMed

    Grether, Gregory F; Kolluru, Gita R; Nersissian, Karen

    2004-08-01

    Colour patches are complex traits, the components of which may evolve independently through a variety of mechanisms. Although usually treated as simple, two-dimensional characters and classified as either structural or pigmentary, in reality colour patches are complicated, three-dimensional structures that often contain multiple pigment types and structural features. The basic dermal chromatophore unit of fishes, reptiles and amphibians consists of three contiguous cell layers. Xanthophores and erythrophores in the outermost layer contain carotenoid and pteridine pigments that absorb short-wave light; iridophores in the middle layer contain crystalline platelets that reflect light back through the xanthophores; and melanophores in the basal layer contain melanins that absorb light across the spectrum. Changes in any one component of a chromatophore unit can drastically alter the reflectance spectrum produced, and for any given adaptive outcome (e.g. an increase in visibility), there may be multiple biochemical or cellular routes that evolution could take, allowing for divergent responses by different populations or species to similar selection regimes. All of the mechanisms of signal evolution that previously have been applied to single ornaments (including whole colour patches) could potentially be applied to the individual components of colour patches. To reach a complete understanding of colour patch evolution, however, it may be necessary to take an explicitly multi-trait approach. Here, we review multiple trait evolution theory and the basic mechanisms of colour production in fishes, reptiles and amphibians, and use a combination of computer simulations and empirical examples to show how multiple trait evolution theory can be applied to the components of single colour patches. This integrative perspective on animal colouration opens up a host of new questions and hypotheses. We offer specific, testable functional hypotheses for the most common pigmentary

  17. Repaired left ventricular free wall rupture after acute myocardial infarction by percutaneous intrapericardial fibrin-glue injection therapy.

    PubMed

    Okonogi, Taichi; Otsuka, Yoritaka; Saito, Taro

    2013-09-01

    Left ventricular free wall rupture is a rare, but occasionally lethal, complication after acute myocardial infarction (AMI). This case report describes a patient who presented with cardiogenic shock due to oozing-type rupture secondary to AMI and successfully underwent percutaneous intrapericardial fibrin-glue injection therapy. Cardiac magnetic resonance imaging demonstrated the thin layer of fibrin that covered the ruptured infarct myocardium immediately after fibrin-glue injection and its disappearance without any complications at 6 months.

  18. Release of alpha 2-plasmin inhibitor from plasma fibrin clots by activated coagulation factor XIII. Its effect on fibrinolysis.

    PubMed Central

    Mimuro, J; Kimura, S; Aoki, N

    1986-01-01

    When blood coagulation takes place in the presence of calcium ions, alpha 2-plasmin inhibitor (alpha 2PI) is cross-linked to fibrin by activated coagulation Factor XIII (XIIIa) and thereby contributes to the resistance of fibrin to fibrinolysis. It was previously shown that the cross-linking reaction is a reversible one, since the alpha 2PI-fibrinogen cross-linked complex could be dissociated. In the present study we have shown that the alpha 2PI-fibrin cross-linking reaction is also a reversible reaction and alpha 2PI which had been cross-linked to fibrin can be released from fibrin by disrupting the equilibrium, resulting in a decrease of its resistance to fibrinolysis. When the fibrin clot formed from normal plasma in the presence of calcium ions was suspended in alpha 2PI-deficient plasma of buffered saline, alpha 2PI was gradually released from fibrin on incubation. When alpha 2PI was present in the suspending milieu, the release was decreased inversely to the concentrations of alpha 2PI in the suspending milieu. The release was accelerated by supplementing XIIIa or the presence of a high concentration of the NH2-terminal 12-residue peptide of alpha 2PI (N-peptide) which is cross-linked to fibrin in exchange for the release of alpha 2PI. When the release of alpha 2PI from fibrin was accelerated by XIIIa or N-peptide, the fibrin became less resistant to the fibrinolytic process, resulting in an acceleration of fibrinolysis which was proportional to the degree of the release of alpha 2PI. These results suggest the possibility that alpha 2PI could be released from fibrin in vivo by disrupting the equilibrium of the alpha 2PI-fibrin cross-linking reaction, and that the release would result in accelerated thrombolysis. Images PMID:2419360

  19. Percutaneous BioOrganic Sealing of Duodenal Fistulas: Case Report and Review of Biological Sealants with Potential Use in Interventional Radiology

    SciTech Connect

    Wadhwa, Vibhor; Leeper, William R.; Tamrazi, Anobel

    2015-08-15

    Biological sealants are being increasingly used in a variety of surgical specialties for their hemostatic and sealing capabilities. However, their use in interventional radiology has not been widely reported. The authors describe a case of duodenal perforation occurring after 15 years of gastric bypass surgery, in whom surgical diversion was unsuccessfully attempted and the leakage was successfully controlled using percutaneous administration of a combination of biological and organic sealants.

  20. Methods of Making and Using Shape Memory Polymer Composite Patches

    NASA Technical Reports Server (NTRS)

    Hood, Patrick J.

    2011-01-01

    A method of repairing a composite component having a damaged area including: laying a composite patch over the damaged area: activating the shape memory polymer resin to easily and quickly mold said patch to said damaged area; deactivating said shape memory polymer so that said composite patch retains the molded shape; and bonding said composite patch to said damaged part.

  1. Three-dimensional structure and cytokine distribution of platelet-rich fibrin

    PubMed Central

    Bai, Meng-Yi; Wang, Ching-Wei; Wang, Jyun-Yi; Lin, Ming-Fang; Chan, Wing P

    2017-01-01

    OBJECTIVES: Previous reports have revealed that several cytokines (including platelet-derived growth factor-BB, transforming growth factors-β1 and insulin-like growth factor-1) can enhance the rate of bone formation and synthesis of extracellular matrix in orthopaedics or periodontology. This study aimed to determine the concentration of cytokines within platelet-rich fibrin microstructures and investigate whether there are differences in the different portions of platelet-rich fibrin, which has implications for proper clinical use of platelet-rich fibrin gel. METHODS: Whole blood was obtained from six New Zealand rabbits (male, 7 to 39 weeks old, weight 2.7-4 kg); it was then centrifuged for preparation of platelet-rich fibrin gels and harvest of plasma. The resultant platelet-rich fibrin gels were used for cytokine determination, histological analyses and scanning electron microscopy. All plasmas obtained were subject to the same cytokine determination assays for the purpose of comparison. RESULTS: Cytokines platelet-derived growth factor-BB and transforming growth factor-β1 formed concentration gradients from high at the red blood cell end of the platelet-rich fibrin gel (p=1.88×10-5) to low at the plasma end (p=0.19). Insulin-like growth factor-1 concentrations were similar at the red blood cell and plasma ends. The porosities of the platelet-rich fibrin samples taken in sequence from the red blood cell end to the plasma end were 6.5% ± 4.9%, 24.8% ± 7.5%, 30.3% ± 8.5%, 41.4% ± 12.3%, and 40.3% ± 11.7%, respectively, showing a gradual decrease in the compactness of the platelet-rich fibrin network. CONCLUSION: Cytokine concentrations are positively associated with platelet-rich fibrin microstructure and portion in a rabbit model. As platelet-rich fibrin is the main entity currently used in regenerative medicine, assessing cytokine concentration and the most valuable portion of PRF gels is essential and recommended to all physicians. PMID:28273236

  2. Coal-tar pavement sealants might substantially increase children's PAH exposures

    USGS Publications Warehouse

    Williams, E. Spencer; Mahler, Barbara J.; Van Metre, Peter C.

    2012-01-01

    Dietary ingestion has been identified repeatedly as the primary route of human exposure to polycyclic aromatic hydrocarbons (PAHs), seven of which are classified as probable human carcinogens (B2 PAHs) by the U.S. EPA. Humans are exposed to PAHs through ingestion of cooked and uncooked foods, incidental ingestion of soil and dust, inhalation of ambient air, and absorption through skin. Although PAH sources are ubiquitous in the environment, one recently identified PAH source stands out: Coal-tar-based pavement sealant—a product applied to many parking lots, driveways, and even playgrounds primarily in the central, southern, and eastern U.S.—has PAH concentrations 100–1000 times greater than most other PAH sources. It was reported recently that PAH concentrations in house dust in residences adjacent to parking lots with coal-tar-based sealant were 25 times higher than in residences adjacent to unsealed asphalt parking lots.

  3. Dextran/Albumin hydrogel sealant for Dacron(R) vascular prosthesis.

    PubMed

    Lisman, Anna; Butruk, Beata; Wasiak, Iga; Ciach, Tomasz

    2014-05-01

    In this paper, the authors describe a novel type of hydrogel coating prepared from the copolymer of human serum albumin and oxidized dextran. The material was designed as a hydrogel sealant for polyester (Dacron®)-based vascular grafts. Dextran was chosen as a coating material due to its anti-thrombogenic properties. Prepared hydrogels were compared with similar, already known biomaterial made from gelatine with the same cross-linking agent. Obtained hydrogels, prepared from various ratios of oxidized dextran/albumin or oxidized dextran/gelatine, showed different cross-linking densities, which caused differences in swelling, degradation rate and mechanical properties. Permeability tests confirmed the complete tightness of the hydrogel-modified prosthesis. Results showed that application of the hydrogel coating provided leakage-free prosthesis and eliminated the need of pre-clotting.

  4. Novel Chemically-Bonded Phosphate Ceramic Borehole Sealants (Ceramicretes) for Arctic Environments

    SciTech Connect

    Shirish Patil; Godwin A. Chukwu; Gang Chen; Santanu Khataniar

    2008-12-31

    Novel chemically bonded phosphate ceramic borehole sealant, i.e. Ceramicrete, has many advantages over conventionally used permafrost cement at Alaska North Slope (ANS). However, in normal field practices when Ceramicrete is mixed with water in blenders, it has a chance of being contaminated with leftover Portland cement. In order to identify the effect of Portland cement contamination, recent tests have been conducted at BJ services in Tomball, TX as well as at the University of Alaska Fairbanks with Ceramicrete formulations proposed by the Argonne National Laboratory. The tests conducted at BJ Services with proposed Ceramicrete formulations and Portland cement contamination have shown significant drawbacks which has caused these formulations to be rejected. However, the newly developed Ceramicrete formulation at the University of Alaska Fairbanks has shown positive results with Portland cement contamination as well as without Portland cement contamination for its effective use in oil well cementing operations at ANS.

  5. Influence of etching time and bonding strategies on the microshear bond strength of self- and light-cured pit-and-fissure sealants.

    PubMed

    Souza-Junior, Eduardo José; Borges, Boniek Castillo Dutra; Montes, Marcos Antônio Japiassú Resende; Alonso, Roberta Caroline Bruschi; Ambrosano, Glaucia Maria Bovi; Sinhoreti, Mário Alexandre Coelho

    2012-01-01

    This study evaluated the impact of extended etching and bonding strategies on the microshear bond strength of three sealant materials. Two pit-and-fissure sealants [FluroShield, Dentsply (light-cured) and AlphaSeal, DFL (self-cured)] and one light-cured flowable composite resin (Permaflo, Ultradent) were evaluated according to different enamel etching times (15 s or 30 s) and bonding procedures (no adhesive application, application of primer/hydrophobic resin or hydrophobic resin only). Intact enamel blocks were obtained from bovine teeth and sealed via the tested protocols. After 24 h, the microshear bond strength test was performed in a universal testing machine at a crosshead speed of 0.5 mm/min. Failure modes were classified by stereomicroscopy. Data were submitted to a three-way ANOVA and to Tukey's test (α=0.05). There was no statistically significant difference (p>0.05) among the materials. Permaflo showed higher bond strength when etched for 30 s alone. Enamel overetching decreased the bond strength of the light-cured sealant. Primer/bond previous treatment improved bond performance for AlphaSeal. In conclusion, from the tested conditions, all sealant materials presented similar bond strength values in relation to bonding protocol and etching time. The flowable composite can be used as a pit-and-fissure sealant. The use of a three-step adhesive system was essential for the self-cured sealant application.

  6. Sintering behavior of lanthanide-containing glass-ceramic sealants for solid oxide fuel cells

    SciTech Connect

    Goel, Ashutosh; Reddy, Allu Amarnath; Pascual, Maria J.; Gremillard, Laurent; Malchere, Annie; Ferreira, Jose M.

    2012-05-01

    This article reports on the influence of different lanthanides (La, Nd, Gd and Yb) on sintering behavior of alkaline-earth aluminosilicate glass-ceramics sealants for their application in solid oxide fuel cells (SOFC). All the glasses have been prepared by melt-quench technique. The in situ follow up of sintering behavior of glass powders has been done by high temperature - environmental scanning electron microscope (HT-ESEM) and hot-stage microscope (HSM) while the crystalline phase evolution and assemblage has been analyzed by x-ray diffraction (XRD) and scanning electron microscopy (SEM). All the glass compositions exhibit a glass-in-glass phase separation followed by two stage sintering resulting in well sintered glass powder compacts after heat treatment at 850 C for 1 h. Diopside (CaMgSi{sub 2}O{sub 6}) based phases constituted the major crystalline part in glass-ceramics followed by some minor phases. The increase in lanthanide content in glasses suppressed their tendency towards devitrification, thus, resulting in glass-ceramics with high amount of residual glassy phase (50-96 wt.%) which is expected to facilitate their self-healing behavior during SOFC operation. The electrical conductivity of the investigated glass-ceramics varied between (1.19 and 7.33) x 10{sup -7} S cm{sup -1} (750-800 C), and depended on the ionic field strength of lanthanide cations. Further experimentation with respect to the long term thermal and chemical stability of residual glassy phase under SOFC operation conditions along with high temperature viscosity measurements will be required in order to elucidate the potential of these glass-ceramics as self-healing sealants.

  7. Measles vaccination using a microneedle patch.

    PubMed

    Edens, Chris; Collins, Marcus L; Ayers, Jessica; Rota, Paul A; Prausnitz, Mark R

    2013-07-25

    Measles vaccination programs would benefit from delivery methods that decrease cost, simplify logistics, and increase safety. Conventional subcutaneous injection is limited by the need for skilled healthcare professionals to reconstitute and administer injections, and by the need for safe needle handling and disposal to reduce the risk of disease transmission through needle re-use and needlestick injury. Microneedles are micron-scale, solid needles coated with a dry formulation of vaccine that dissolves in the skin within minutes after patch application. By avoiding the use of hypodermic needles, vaccination using a microneedle patch could be carried out by minimally trained personnel with reduced risk of blood-borne disease transmission. The goal of this study was to evaluate measles vaccination using a microneedle patch to address some of the limitations of subcutaneous injection. Viability of vaccine virus dried onto a microneedle patch was stabilized by incorporation of the sugar, trehalose, and loss of viral titer was less than 1 log10(TCID50) after storage for at least 30 days at room temperature. Microneedle patches were then used to immunize cotton rats with the Edmonston-Zagreb measles vaccine strain. Vaccination using microneedles at doses equaling the standard human dose or one-fifth the human dose generated neutralizing antibody levels equivalent to those of a subcutaneous immunization at the same dose. These results show that measles vaccine can be stabilized on microneedles and that vaccine efficiently reconstitutes in vivo to generate a neutralizing antibody response equivalent to that generated by subcutaneous injection.

  8. Transdermal patch drug delivery interactions with exercise.

    PubMed

    Lenz, Thomas L; Gillespie, Nicole

    2011-03-01

    Transdermal drug delivery systems, such as the transdermal patch, continue to be a popular and convenient way to administer medications. There are currently several medications that use a transdermal patch drug delivery system. This article describes the potential untoward side effects of increased drug absorption through the use of a transdermal patch in individuals who exercise or participate in sporting events. Four studies have been reported that demonstrate a significant increase in the plasma concentration of nitroglycerin when individuals exercise compared with rest. Likewise, several case reports and two studies have been conducted that demonstrate nicotine toxicity and increased plasma nicotine while wearing a nicotine patch in individuals who exercise or participate in sporting events compared with rest. Healthcare providers, trainers and coaches should be aware of proper transdermal patch use, especially while exercising, in order to provide needed information to their respective patients and athletes to avoid potential untoward side effects. Particular caution should be given to individuals who participate in an extreme sporting event of long duration. Further research that includes more medications is needed in this area.

  9. Activated Membrane Patches Guide Chemotactic Cell Motility

    PubMed Central

    Hecht, Inbal; Skoge, Monica L.; Charest, Pascale G.; Ben-Jacob, Eshel; Firtel, Richard A.; Loomis, William F.; Levine, Herbert; Rappel, Wouter-Jan

    2011-01-01

    Many eukaryotic cells are able to crawl on surfaces and guide their motility based on environmental cues. These cues are interpreted by signaling systems which couple to cell mechanics; indeed membrane protrusions in crawling cells are often accompanied by activated membrane patches, which are localized areas of increased concentration of one or more signaling components. To determine how these patches are related to cell motion, we examine the spatial localization of RasGTP in chemotaxing Dictyostelium discoideum cells under conditions where the vertical extent of the cell was restricted. Quantitative analyses of the data reveal a high degree of spatial correlation between patches of activated Ras and membrane protrusions. Based on these findings, we formulate a model for amoeboid cell motion that consists of two coupled modules. The first module utilizes a recently developed two-component reaction diffusion model that generates transient and localized areas of elevated concentration of one of the components along the membrane. The activated patches determine the location of membrane protrusions (and overall cell motion) that are computed in the second module, which also takes into account the cortical tension and the availability of protrusion resources. We show that our model is able to produce realistic amoeboid-like motion and that our numerical results are consistent with experimentally observed pseudopod dynamics. Specifically, we show that the commonly observed splitting of pseudopods can result directly from the dynamics of the signaling patches. PMID:21738453

  10. Characterizing the morphology of protein binding patches.

    PubMed

    Malod-Dognin, Noël; Bansal, Achin; Cazals, Frédéric

    2012-12-01

    Let the patch of a partner in a protein complex be the collection of atoms accounting for the interaction. To improve our understanding of the structure-function relationship, we present a patch model decoupling the topological and geometric properties. While the geometry is classically encoded by the atomic positions, the topology is recorded in a graph encoding the relative position of concentric shells partitioning the interface atoms. The topological-geometric duality provides the basis of a generic dynamic programming-based algorithm comparing patches at the shell level, which may favor topological or geometric features. On the biological side, we address four questions, using 249 cocrystallized heterodimers organized in biological families. First, we dissect the morphology of binding patches and show that Nature enjoyed the topological and geometric degrees of freedom independently while retaining a finite set of qualitatively distinct topological signatures. Second, we argue that our shell-based comparison is effective to perform atomic-level comparisons and show that topological similarity is a less stringent than geometric similarity. We also use the topological versus geometric duality to exhibit topo-rigid patches, whose topology (but not geometry) remains stable upon docking. Third, we use our comparison algorithms to infer specificity-related information amidst a database of complexes. Finally, we exhibit a descriptor outperforming its contenders to predict the binding affinities of the affinity benchmark. The softwares developed with this article are availablefrom http://team.inria.fr/abs/vorpatch_compatch/.

  11. Microneedle patches for vaccination in developing countries.

    PubMed

    Arya, Jaya; Prausnitz, Mark R

    2016-10-28

    Millions of people die of infectious diseases each year, mostly in developing countries, which could largely be prevented by the use of vaccines. While immunization rates have risen since the introduction of the Expanded Program on Immunization (EPI), there remain major challenges to more effective vaccination in developing countries. As a possible solution, microneedle patches containing an array of micron-sized needles on an adhesive backing have been developed to be used for vaccine delivery to the skin. These microneedle patches can be easily and painlessly applied by pressing against the skin and, in some designs, do not leave behind sharps waste. The patches are single-dose, do not require reconstitution, are easy to administer, have reduced size to simplify storage, transportation and waste disposal, and offer the possibility of improved vaccine immunogenicity, dose sparing and thermostability. This review summarizes vaccination challenges in developing countries and discusses advantages that microneedle patches offer for vaccination to address these challenges. We conclude that microneedle patches offer a powerful new technology that can enable more effective vaccination in developing countries.

  12. Surface patterning of nanoparticles with polymer patches

    SciTech Connect

    Choueiri, Rachelle M.; Galati, Elizabeth; Thérien-Aubin, Héloïse; Klinkova, Anna; Larin, Egor M.; Querejeta-Fernández, Ana; Han, Lili; Xin, Huolin L.; Gang, Oleg; Zhulina, Ekaterina B.; Rubinstein, Michael; Kumacheva, Eugenia

    2016-08-24

    Patterning of colloidal particles with chemically or topographically distinct surface domains (patches) has attracted intense research interest. Surface-patterned particles act as colloidal analogues of atoms and molecules serve as model systems in studies of phase transitions in liquid systems, behave as ‘colloidal surfactants’ and function as templates for the synthesis of hybrid particles. The generation of micrometre- and submicrometre-sized patchy colloids is now efficient but surface patterning of inorganic colloidal nanoparticles with dimensions of the order of tens of nanometres is uncommon. Such nanoparticles exhibit size- and shape-dependent optical, electronic and magnetic properties, and their assemblies show new collective properties. At present, nanoparticle patterning is limited to the generation of two-patch nanoparticles and nanoparticles with surface ripples or a ‘raspberry’ surface morphology. We demonstrate nanoparticle surface patterning, which utilizes thermodynamically driven segregation of polymer ligands from a uniform polymer brush into surface-pinned micelles following a change in solvent quality. Patch formation is reversible but can be permanently preserved using a photocrosslinking step. The methodology offers the ability to control the dimensions of patches, their spatial distribution and the number of patches per nanoparticle, in agreement with a theoretical model. The versatility of the strategy is demonstrated by patterning nanoparticles with different dimensions, shapes and compositions, tethered with various types of polymers and subjected to different external stimuli. Furthermore, these patchy nanocolloids have potential applications in fundamental research, the self-assembly of nanomaterials, diagnostics, sensing and colloidal stabilization.

  13. Surface patterning of nanoparticles with polymer patches

    NASA Astrophysics Data System (ADS)

    Choueiri, Rachelle M.; Galati, Elizabeth; Thérien-Aubin, Héloïse; Klinkova, Anna; Larin, Egor M.; Querejeta-Fernández, Ana; Han, Lili; Xin, Huolin L.; Gang, Oleg; Zhulina, Ekaterina B.; Rubinstein, Michael; Kumacheva, Eugenia

    2016-10-01

    Patterning of colloidal particles with chemically or topographically distinct surface domains (patches) has attracted intense research interest. Surface-patterned particles act as colloidal analogues of atoms and molecules, serve as model systems in studies of phase transitions in liquid systems, behave as ‘colloidal surfactants’ and function as templates for the synthesis of hybrid particles. The generation of micrometre- and submicrometre-sized patchy colloids is now efficient, but surface patterning of inorganic colloidal nanoparticles with dimensions of the order of tens of nanometres is uncommon. Such nanoparticles exhibit size- and shape-dependent optical, electronic and magnetic properties, and their assemblies show new collective properties. At present, nanoparticle patterning is limited to the generation of two-patch nanoparticles, and nanoparticles with surface ripples or a ‘raspberry’ surface morphology. Here we demonstrate nanoparticle surface patterning, which utilizes thermodynamically driven segregation of polymer ligands from a uniform polymer brush into surface-pinned micelles following a change in solvent quality. Patch formation is reversible but can be permanently preserved using a photocrosslinking step. The methodology offers the ability to control the dimensions of patches, their spatial distribution and the number of patches per nanoparticle, in agreement with a theoretical model. The versatility of the strategy is demonstrated by patterning nanoparticles with different dimensions, shapes and compositions, tethered with various types of polymers and subjected to different external stimuli. These patchy nanocolloids have potential applications in fundamental research, the self-assembly of nanomaterials, diagnostics, sensing and colloidal stabilization.

  14. Dental Sealants

    MedlinePlus

    ... form does not collect any actual information. External Web Site Policy This graphic notice ( ) means that you are ... the link. Home Contact Us Viewers and Players Site Map FOIA Web Policies Privacy Policy National Institute of Dental and ...

  15. 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.

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

    PubMed

    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 degrees C, which is about 30 degrees C higher than that of the fibrinogen. The hydrogel has an initial water-uptake ratio of approximately 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.

  17. Bone repair with a form of BMP-2 engineered for incorporation into fibrin cell ingrowth matrices.

    PubMed

    Schmoekel, Hugo G; Weber, Franz E; Schense, Jason C; Grätz, Klaus W; Schawalder, Peter; Hubbell, Jeffrey A

    2005-02-05

    Most growth factors naturally involved in development and regeneration demonstrate strong binding to the extracellular matrix and are retained there until being locally mobilized by cells. In spite of this feedback between cell activity and growth factor mobilization in the extracellular matrix, this approach has not been extensively explored in therapeutic situations. We present an engineered bone morphogenetic protein-2 (BMP-2) fusion protein that mimics such function in a surgically relevant matrix, fibrin, incorporated into the matrix until it is locally liberated by cell surface-associated proteases. A tripartite fusion protein, denoted TG-pl-BMP-2, was designed and produced recombinantly. An N-terminal transglutaminase substrate (TG) domain provides covalent attachment to fibrin during coagulation under the influence of the blood transglutaminase factor XIIIa. A central plasmin substrate (pl) domain provides a cleavage site for local release of the attached growth factor from the fibrin matrix under the influence of cell-activated plasmin. A C-terminal human BMP-2 domain provides osteogenic activity. TG-pl-BMP-2 in fibrin was evaluated in vivo in critical-size craniotomy defects in rats, where it induced 76% more defect healing with bone at 3 weeks with a dose of 1 mug/defect than wildtype BMP-2 in fibrin. After a dosing study in rabbits, the engineered growth factor in fibrin was evaluated in a prospective clinical study for pancarpal fusion in dogs, where it induced statistically faster and more extensive bone bridging than equivalent treatment with cancellous bone autograft. The strong healing response shown by fibrin including a bound BMP-2 variant suggests that with the combination of bound growth factor and ingrowth matrix, it may be possible to improve upon the natural growth factor and even upon tissue autograft.

  18. Fibrin and plasminogen structures essential to stimulation of plasmin formation by tissue-type plasminogen activator.

    PubMed

    Suenson, E; Petersen, L C

    1986-04-22

    Plasminogen activation catalysed by tissue-type plasminogen activator (t-PA) has been examined in the course of concomitant fibrin formation and degradation. Plasmin generation has been measured by the spectrophotometric method of Petersen et al. (Biochem. J. 225 (1985) 149-158), modified so as to allow for light scattering caused by polymerized fibrin. Glu1-, Lys77- and Val442-plasminogen are activated in the presence of fibrinogen, des A- and des AB-fibrin and the rate of plasmin formation is found to be greatly enhanced by both des A- and des AB-fibrin polymer. Plasmin formation from Glu1- and Lys77-plasminogen yields a sigmoidal curve, whereas a linear increase is obtained with Val442-plasminogen. The rate of plasmin formation from Glu1- and Lys77-plasminogen declines in parallel with decreasing turbidity of the fibrin polymer effector. In order to study the effect of polymerization, this has been inhibited by the synthetic polymerization site analogue Gly-Pro-Arg-Pro, by fibrinogen fragment D1 or by prior methylene blue-dependent photooxidation of the fibrinogen used. Inhibition of polymerization by Gly-Pro-Arg-Pro reduces plasmin generation to the low rate observed in the presence of fibrinogen. Antipolymerization with fragment D1 or photooxidation has the same effect on Glu1-plasminogen activation, but only partially reduces and delays the stimulatory effect on Lys77- and Val442-plasminogen activation. The results suggest that protofibril formation (and probably also gelation) of fibrin following fibrinopeptide release is essential to its stimulatory effect. The gradual increase and subsequent decline in the rate of plasmin formation from Glu1- or Lys77-plasminogen during fibrinolysis may be explained by sequential exposure, modification and destruction of different t-PA and plasminogen binding sites in fibrin polymer.

  19. 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

  20. Deformation of Polar Cap Patches During Substorms

    NASA Astrophysics Data System (ADS)

    Zou, S.; Ridley, A. J.; Nicolls, M. J.; Coster, A. J.; Thomas, E. G.; Ruohoniemi, J. M.; Hampton, D.

    2015-12-01

    Polar cap patches refer to the islands of high F-region plasma density within the polar cap. Their formation on the dayside and deformation on the nightside are not well understood. The F-layer ionosphere density is strongly influenced by electric field, thermospheric wind as well as soft particle precipitation. This study combines observations from multiple instruments, including Poker Flat incoherent scatter radar, GPS TEC and optical instruments, as well as the Global Ionosphere and Thermosphere Model (GITM), to investigate the effects of highly structured electric fields and winds on the deformation of polar cap patches during substorms. We will also discuss variations of the auroral emissions associated with the patch evolution.

  1. Tunable nano dispersed LC based patch antenna

    NASA Astrophysics Data System (ADS)

    Karim, Afaque; Yadav, Harsh; Ahmad, Shakeb

    2015-06-01

    This paper presents Patch antenna based on pure and Nano dispersed liquid crystals (LCs) for earth and space applications. Patch antenna are one of the most attractive antennas designed for RF frequency. To fulfill the demand of modern antenna i.e. tunability, a design of LC based patch antenna with optimum frequency of 15 GHz is investigated. In this design, NLC and ZnO doped NLC were used as a dielectric substrate. Its dielectric permittivity was controlled by biasing voltage. The dielectric properties of the 4-Cyano-4' -pentylbiphenyl (5CB) nematic liquid crystal (NLC), and NLC doped with Zinc oxide (ZnO) Nanoparticles was studied at room temperature. The concentration of doping material was 0.5% by w.t. in ZnO. Results shows that dielectric parameters are strong function of frequency and applied bias voltage. Moreover, Using doped NLC as dielectric substrate one gets more tunability or shift in resonant frequency in the proposed geometry.

  2. Cell repair: Revisiting the patch hypothesis

    PubMed Central

    Davenport, Nicholas R.

    2016-01-01

    ABSTRACT Plasma membrane damage elicits a complex and dynamic cellular response. A vital component of this response, membrane resealing, is thought to arise from fusion of intracellular membranous compartments to form a temporary, impermeant patch at the site of damage; however, this hypothesis has been difficult to confirm visually. By utilizing advanced microscopy technologies with high spatiotemporal resolution in wounded Xenopus laevis oocytes, we provide the first direct visualization of the membrane fusion events predicted by the patch hypothesis; we show the barrier formed by patching is capable of abating exchange of material across the plasma membrane within seconds. Profound changes also occur to the plasma membrane surrounding wounds; lipid remodeling is accompanied by membrane fusion events, both conventional (e.g., exocytosis) and novel (e.g., “explodosis”). Further, we reveal additional complexity in wound-induced subcellular patterning, supporting existing evidence that extensive interactions between lipid, protein, and ionic signaling pathways shape the cellular wound response. PMID:28042380

  3. Boolean Operations with Prism Algebraic Patches

    PubMed Central

    Bajaj, Chandrajit; Paoluzzi, Alberto; Portuesi, Simone; Lei, Na; Zhao, Wenqi

    2009-01-01

    In this paper we discuss a symbolic-numeric algorithm for Boolean operations, closed in the algebra of curved polyhedra whose boundary is triangulated with algebraic patches (A-patches). This approach uses a linear polyhedron as a first approximation of both the arguments and the result. On each triangle of a boundary representation of such linear approximation, a piecewise cubic algebraic interpolant is built, using a C1-continuous prism algebraic patch (prism A-patch) that interpolates the three triangle vertices, with given normal vectors. The boundary representation only stores the vertices of the initial triangulation and their external vertex normals. In order to represent also flat and/or sharp local features, the corresponding normal-per-face and/or normal-per-edge may be also given, respectively. The topology is described by storing, for each curved triangle, the two triples of pointers to incident vertices and to adjacent triangles. For each triangle, a scaffolding prism is built, produced by its extreme vertices and normals, which provides a containment volume for the curved interpolating A-patch. When looking for the result of a regularized Boolean operation, the 0-set of a tri-variate polynomial within each such prism is generated, and intersected with the analogous 0-sets of the other curved polyhedron, when two prisms have non-empty intersection. The intersection curves of the boundaries are traced and used to decompose each boundary into the 3 standard classes of subpatches, denoted in, out and on. While tracing the intersection curves, the locally refined triangulation of intersecting patches is produced, and added to the boundary representation. PMID:21516262

  4. A fibrin encapsulated liposomes-in-chitosan matrix (FLCM) for delivering water-soluble drugs. Influences of the surface properties of liposomes and the crosslinked fibrin network.

    PubMed

    Chung, Tze-Wen; Yang, Min-Chia; Tsai, Wei-Jean

    2006-03-27

    A depot drug delivery system, fibrin encapsulated liposome-in-chitosan matrix (FLCM), has been developed to deliver a water-soluble drug which is configured by a porous chitosan matrix containing a bovine fibrin network encapsulated different surface properties of liposomes. Quinacrine (QR), a water-soluble, low-molecular weight fluorescent marker, is used as a model drug to evaluate the delivery characteristics of the system. The SEM photographs show that the fibrin network adheres to the surfaces and pores of the chitosan matrix of a FLCM system. The QR release periods of the FLCM are sustained for about four times longer than those of QR encapsulated into the liposomes. However, the QR release periods and profiles of the FLCM are influenced by the surface properties of liposomes. The release of QR from FLCM is sustained for 9 days for neutral liposomes and only 5 days for PEG modified liposomes (PEG-liposome). After crosslinking the fibrin network of the FLCM with 0.5% of glutaldehyde, the release of QR is further sustained for 17 days with good linear profiles (e.g., 13 days) and with 50% of reduced burst release compared with those of without crosslinking, indicating that the stability of the fibrin network plays an important role on QR release of the system. More interestingly, the release periods and profiles of QR of the FLCM system are highly similar to those of Tirofiban, low-molecular weight of a water-soluble clinical cardiovascular drug, although the study has been done by human platelet poor plasma instead of bovine fibrinogen as a source of fibrin network. It suggests that the QR is a suitable model for investigating the drug delivery behaviors for water-soluble, low-molecular weight drugs of the FLCM. In conclusion, with QR as a model drug, FLCM with crosslinked fibrin network can effectively sustain the release of QR for 17 days but the release profiles are influenced by the surface properties of encapsulated liposomes. This study suggests that

  5. Epidural blood patch and acute varicella.

    PubMed

    Martin, David P; Bergman, Bradley D; Berger, Ines H

    2004-12-01

    We present the case of a 38-yr-old woman who required an epidural blood patch in the context of acute varicella (chickenpox). The unique risks in this case include the possible triggering of central nervous system complications after the introduction of viremic blood into the epidural or intrathecal space. However, the risk was believed to be acceptable because the patient was receiving antiviral coverage. She enjoyed complete relief of her headache but experienced transient back and leg pain. Leptomeningeal irritation caused by acute varicella infection may put patients at increased risk for pain after epidural blood patch.

  6. Patch Clamping Protoplasts from Vascular Plants 1

    PubMed Central

    Elzenga, J. Theo M.; Keller, Christopher P.; Van Volkenburgh, Elizabeth

    1991-01-01

    A method is described for the isolation of protoplasts (Pisum sativum, Phaseolus vulgaris, Avena sativa, Arabidopsis thaliana) in preparation for ion flux studies using patch clamp electrophysiology. Protoplasts that have been exposed to hydrolytic, cell wall degrading, enzymes for as little as 5 minutes form gigaseals (seal resistance higher than 10 giga Ohm) with the patch pipette with success rates greater than 40%. Sealing of these protoplasts is fast, averaging less than 2 minutes. This method yields high rates of gigaseal formation in a variety of tissues from both monocots and dicots and will enhance data collection in ion flux studies of plasma membranes of vascular plants. PMID:16668586

  7. Lightweight Material Patches Allow for Quick Repairs

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Cornerstone Research Group Inc., of Dayton, Ohio, has been the recipient of 16 Small Business Innovation Research (SBIR) contracts with NASA with a variety of different focuses, including projects like creating inflatable structures for radio frequency antennas and, most recently, healable polymer matrix composites for future space vehicles. One of its earlier SBIR contracts, with Kennedy Space Center, led to the development of a new type of structural patch for a variety of consumer uses: Rubbn Repair, for automotive uses; and Rec Repair for the outdoors and adventure market. Both are flexible, heat-activated structural patches.

  8. Automated determination of cross-linked fibrin derivatives in plasma.

    PubMed

    Elms, M J; Bundesen, P G; Rowbury, D; Goodall, S; Wakeham, N; Rowell, J A; Hillyard, C J; Rylatt, D B

    1993-02-01

    Automated assays for the measurement of cross-linked fibrin derivatives in plasma (XL-FbDP) have been developed utilizing latex beads coated with anti-D dimer monoclonal antibody (DD-3B6/22) for both the Cobas Fara Chemistry Centrifugal and the Cobas Mira analysers (Roche, Basle, Switzerland). The analysers were programmed to mix plasma and latex reagent simultaneously and analyse absorbance changes over a 10-15 min period. Results were interpolated by the analyser from a standard curve derived from a polymer of D-dimer. Both assays had high precision (< 5% CV) for values between 100 and 1000 ng/ml and provided clear discrimination between normal samples and samples from patients suffering from the thrombotic diseases, DVT/PE and DIC. The results obtained for XL-FbDP determination with both methods compared well with established methods: a high correlation was obtained with a semi-quantitative manual latex method for both the Fara (r = 0.92) and Mira (r = 0.83) and correlations (r) of 0.81 (Fara) and 0.84 (Mira) were obtained with an enzyme immunoassay (EIA). Correlation between the two automated procedures was high (r = 0.96). The automated method will enable laboratories to provide a rapid and accurate quantitation of XL-FbDP.

  9. The interplay between tissue plasminogen activator domains and fibrin structures in the regulation of fibrinolysis: kinetic and microscopic studies

    PubMed Central

    Thelwell, Craig; Williams, Stella C.; Silva, Marta M. C. G.; Szabó, László; Kolev, Krasimir

    2011-01-01

    Regulation of tissue-type plasminogen activator (tPA) depends on fibrin binding and fibrin structure. tPA structure/function relationships were investigated in fibrin formed by high or low thrombin concentrations to produce a fine mesh and small pores, or thick fibers and coarse structure, respectively. Kinetics studies were performed to investigate plasminogen activation and fibrinolysis in the 2 types of fibrin, using wild-type tPA (F-G-K1-K2-P, F and K2 binding), K1K1-tPA (F-G-K1-K1-P, F binding), and delF-tPA (G-K1-K2-P, K2 binding). There was a trend of enzyme potency of tPA > K1K1-tPA > delF-tPA, highlighting the importance of the finger domain in regulating activity, but the differences were less apparent in fine fibrin. Fine fibrin was a better surface for plasminogen activation but more resistant to lysis. Scanning electron and confocal microscopy using orange fluorescent fibrin with green fluorescent protein-labeled tPA variants showed that tPA was strongly associated with agglomerates in coarse but not in fine fibrin. In later lytic stages, delF-tPA-green fluorescent protein diffused more rapidly through fibrin in contrast to full-length tPA, highlighting the importance of finger domain-agglomerate interactions. Thus, the regulation of fibrinolysis depends on the starting nature of fibrin fibers and complex dynamic interaction between tPA and fibrin structures that vary over time. PMID:20966169

  10. The interplay between tissue plasminogen activator domains and fibrin structures in the regulation of fibrinolysis: kinetic and microscopic studies.

    PubMed

    Longstaff, Colin; Thelwell, Craig; Williams, Stella C; Silva, Marta M C G; Szabó, László; Kolev, Krasimir

    2011-01-13

    Regulation of tissue-type plasminogen activator (tPA) depends on fibrin binding and fibrin structure. tPA structure/function relationships were investigated in fibrin formed by high or low thrombin concentrations to produce a fine mesh and small pores, or thick fibers and coarse structure, respectively. Kinetics studies were performed to investigate plasminogen activation and fibrinolysis in the 2 types of fibrin, using wild-type tPA (F-G-K1-K2-P, F and K2 binding), K1K1-tPA (F-G-K1-K1-P, F binding), and delF-tPA (G-K1-K2-P, K2 binding). There was a trend of enzyme potency of tPA > K1K1-tPA > delF-tPA, highlighting the importance of the finger domain in regulating activity, but the differences were less apparent in fine fibrin. Fine fibrin was a better surface for plasminogen activation but more resistant to lysis. Scanning electron and confocal microscopy using orange fluorescent fibrin with green fluorescent protein-labeled tPA variants showed that tPA was strongly associated with agglomerates in coarse but not in fine fibrin. In later lytic stages, delF-tPA-green fluorescent protein diffused more rapidly through fibrin in contrast to full-length tPA, highlighting the importance of finger domain-agglomerate interactions. Thus, the regulation of fibrinolysis depends on the starting nature of fibrin fibers and complex dynamic interaction between tPA and fibrin structures that vary over time.

  11. PAH concentrations in lake sediment decline following ban on coal-tar-based pavement sealants in Austin, Texas

    USGS Publications Warehouse

    Van Metre, Peter C.; Mahler, Barbara J.

    2013-01-01

    Recent studies have concluded that coal-tar-based pavement sealants are a major source of polycyclic aromatic hydrocarbons (PAHs) in urban settings in large parts of the United States. In 2006, Austin, TX, became the first jurisdiction in the U.S. to ban the use of coal-tar sealants. We evaluated the effect of Austin’s ban by analyzing PAHs in sediment cores and bottom-sediment samples collected in 1998, 2000, 2001, 2012, and 2014 from Lady Bird Lake, the principal receiving water body for Austin urban runoff. The sum concentration of the 16 EPA Priority Pollutant PAHs (∑PAH16) in dated core intervals and surficial bottom-sediment samples collected from sites in the lower lake declined about 44% from 1998–2005 to 2006–2014 (means of 7980 and 4500 μg kg–1, respectively), and by 2012–2014, the decline was about 58% (mean of 3320 μg kg–1). Concentrations of ∑PAH16 in bottom sediment from two of three mid-lake sites decreased by about 71 and 35% from 2001 to 2014. Concentrations at a third site increased by about 14% from 2001 to 2014. The decreases since 2006 reverse a 40-year (1959–1998) upward trend. Despite declines in PAH concentrations, PAH profiles and source-receptor modeling results indicate that coal-tar sealants remain the largest PAH source to the lake, implying that PAH concentrations likely will continue to decline as stocks of previously applied sealant gradually become depleted.

  12. 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.

  13. 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

  14. 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.

  15. Inverse inkjet printed gold micro electrodes for the structured deposition of epithelial cells and fibrin.

    PubMed

    Zehbe, Rolf; Gross, Ulrich; Schubert, Helmut

    2007-11-01

    The micro structured deposition of vital cells is an important challenge in tissue engineering, biosensor technology, and in all research dealing with cell-cell and cell-substrate contacts. Hence, an inkjet printing technology has been developed to manufacture Au-based micro electrodes by sputter coating inversely printed polyester-foils. These electrodes feature minimal structure sizes of 35 microm and consist of an anode and a cathode part. They were used with fibrinogenic epithelial cell suspensions to deposit human keratinocytes (HaCaT), mouse fibroblasts (L-929) and the protein fibrin by applying DC voltage. Subsequently cells were electrophoretically attracted to the anode, following exactly its shape, while the insoluble fibrin was simultaneously precipitated due to the electrically mediated polymerization of the soluble fibrinogen molecule. Furthermore, it was demonstrated that this technique is suitable to co-deposit both cell types in a layered fashion. The lower voltage boundary for successful deposition was set at approximately 0.8 V needed for the conversion of fibrinogen into fibrin, while the upper voltage boundary was set at approximately 1.85 V, when commencing electrolysis inhibited the deposition of vital cells. Subsequent to the anodic cell-fibrin deposition, cells were cultivated for up to 4 days and then characterized by FDA+EB staining, methyl violet staining, MNF staining and SEM. The conversion from fibrinogen into fibrin was studied using ATR/FTIR.

  16. 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

  17. Cell sourcing and culture conditions for fibrin-based valve constructs.

    PubMed

    Williams, Chrysanthi; Johnson, Sandra L; Robinson, Paul S; Tranquillo, Robert T

    2006-06-01

    Cell sourcing for tissue-engineered heart valves remains a critical issue. In this work, human dermal fibroblasts (HDF) or porcine valve interstitial cells (PVIC) were entrapped in adherent fibrin disk constructs and harvested at 3 and 5 weeks. We compared the fibrin remodeling abilities of each cell type in Dulbecco's Modified Eagle's Medium (DMEM) and DMEM/F12 supplemented with transforming growth factor beta (TGF), and the response of PVIC to DMEM/F12 supplemented with fibroblast growth factor (FGF), a combination of FGF and TGF, and TGF with varying ascorbic acid (AA) concentrations. Culture media were supplemented with serum, insulin, AA, a fibrinolysis inhibitor, and antibiotics. DMEM maximized collagen and elastin deposition by HDF, while DMEM/F12 with FGF yielded the highest fibrin remodeling response by PVIC. HDF degraded fibrin slower than PVIC, and PVIC constructs had higher cellularity than HDF constructs in DMEM and DMEM/F12 at 3 weeks. FGF addition increased collagen content, collagen deposited per cell, and collagen as percentage of total protein compared to medium supplemented with TGF or TGF and FGF. AA addition increased collagen deposition by PVIC, but there was no dose dependence between 50 and 150 microg/mL AA. These results collectively show that PVIC are able to remodel fibrin faster and exhibit greater mechanical stiffening compared to HDF. Conditions for increased collagen deposition are also identified toward the engineering of valve constructs.

  18. The application of plastic compression to modulate fibrin hydrogel mechanical properties.

    PubMed

    Haugh, Matthew G; Thorpe, Stephen D; Vinardell, Tatiana; Buckley, Conor T; Kelly, Daniel J

    2012-12-01

    The inherent biocompatibility of fibrin hydrogels makes them an attractive material for use in a wide range of tissue engineering applications. Despite this, their relatively low stiffness and high compliance limits their potential for certain orthopaedic applications. Enhanced mechanical properties are desirable so as to withstand surgical handling and in vivo loading after implantation and additionally, can provide important cues to cells seeded within the hydrogel. Standard methods used to enhance the mechanical properties of biological scaffolds such as chemical or thermal crosslinking cannot be used with fibrin hydrogels as cell seeding and gel formation occurs simultaneously. The objective of this study was to investigate the use of plastic compression as a means to improve the mechanical properties of chondrocyte-seeded fibrin hydrogels and to determine the influence of such compression on cell viability within these constructs. It was found that the application of 80% strain to fibrin hydrogels for 30 min (which resulted in a permanent strain of 47.4%) produced a 2.1-fold increase in the subsequent compressive modulus. Additionally, chondrocyte viability was maintained in the plastically compressed gels with significant cellular proliferation and extracellular matrix accumulation observed over 28 days of culture. In conclusion, plastic compression can be used to modulate the density and mechanical properties of cell-seeded fibrin hydrogels and represents a useful tool for both in theatre and in vitro tissue engineering applications.

  19. Generation of strip-format fibrin-based engineered heart tissue (EHT).

    PubMed

    Schaaf, Sebastian; Eder, Alexandra; Vollert, Ingra; Stöhr, Andrea; Hansen, Arne; Eschenhagen, Thomas

    2014-01-01

    This protocol describes a method for casting fibrin-based engineered heart tissue (EHT) in standard 24-well culture dishes. In principle, a hydrogel tissue engineering method requires cardiomyocytes, a liquid matrix that forms a gel, a casting mold, and a device that keeps the developing tissue in place. This protocol refers to neonatal rat heart cells as the cell source; the matrix of choice is fibrin, and the tissues are generated in rectangular agarose-casting molds (12 × 3 × 3 mm) prepared in standard 24-well cell culture dishes, in which a pair of flexible silicone posts is suspended from above. A master mix of freshly isolated cells, medium, fibrinogen, and thrombin is pipetted into the casting mold and, over a period of 2 h, polymerizes and forms a fibrin cell block around two silicone posts. Silicone racks holding four pairs of silicone posts each are used to transfer the fresh fibrin cell blocks into new 24-well dishes with culture medium. Without further handling, the cells start to remodel the fibrin gel, form contacts with each other, elongate, and condense the gel to approximately ¼ of the initial volume. Spontaneous and rhythmic contractions start after 1 week. EHTs are viable and relatively stable for several weeks in this format and can be subjected to repeated measurements of contractile function and final morphological and molecular analyses.

  20. Patches for Carotid Artery Endarterectomy: Current Materials and Prospects

    PubMed Central

    Muto, Akihito; Nishibe, Toshiya; Dardik, Herbert; Dardik, Alan

    2009-01-01

    Patch angioplasty is commonly performed after carotid endarterectomy. Randomized prospective trials and meta-analyses have documented improved rates of perioperative and long-term stroke prevention as well as reduced rates of restenosis for patches compared to primary closure of the arteriotomy. Although use of vein patches is considered to be the “gold standard” for patch closure, newer generations of synthetic and biological materials rival outcomes associated with vein patches. Future bioengineered patches are likely to optimize patch performance, both by achieving minimal stroke risk and long-term rates of restenosis, as well as by minimizing the risk of unusual complications of prosthetic patches such as infection and pseudoaneurysm formation; in addition, lessons from bioengineered patches will likely enable construction of bioengineered and tissue-engineered bypass grafts. PMID:19563972

  1. Critical patch sizes for food-web modules.

    PubMed

    Martinson, Holly M; Fagan, William F; Denno, Robert F

    2012-08-01

    Because patch size and connectivity may strongly impact the assemblage of species that occur on a patch, the types of food-web interactions that occur among those species may also depend on spatial structure. Here, we identify whether food-web interactions among salt-marsh-inhabiting arthropods vary with patch size and connectivity, and how such changes in trophic structure might feed back to influence the spatial distribution of prey. In a multiyear survey, patch-restricted predators exhibited steeper occupancy-patch-size relationships than herbivores, and species' critical patch sizes were correlated with overall rarity. As a result, the presence of food-web modules depended strongly on patch size: large and well-connected patches supported complex food-web modules, but only the simplest modules involving the most abundant species were found on small patches. Habitat-generalist spiders dominated on small patches, and predation pressure from such species may contribute to the observed lower densities of mesopredators on small patches. Overall, patch size and connectivity influenced the types of modules present on a patch through differential loss of rare, patch-restricted predators, but predation by generalist predators may be a key mechanism influencing the spatial structure of certain prey species.

  2. Dispersal, patch leaving, and distribution of Homalodisca vitripennis (Hemiptera: Cicadellidae).

    PubMed

    Northfield, Tobin D; Mizell, Russell F; Paini, Dean R; Andersen, Peter C; Brodbeck, Brent V; Riddle, T Charles; Hunter, Wayne B

    2009-02-01

    Homalodisca vitripennis (Germar) and related species have caused millions of dollars in damage to southern California vineyards in recent years through the vectoring of Pierce's disease. However, the effects of surrounding vegetation on the dispersal and distribution of H. vitripennis are poorly understood. Therefore, the relationship between dispersal rates and patch quality was tested, as well as the basic predictions of the marginal value theorem. Additional experiments were conducted to compare the H. vitripennis distribution in an isolated crape myrtle (Lagerstroemia indica) patch and a L. indica patch bordering two alternative host patches. In mark-release-recapture tests, H. vitripennis dispersed farther from the release point in a patch of low-quality host plants (Prunus persica) than in patches of high-quality host plants (L. indica). In addition, H. vitripennis remained in L. indica patches longer than in P. persica patches and adjusted patch residence times in P. persica in correlation with known changes in plant physiology. These data suggest that H. vitripennis follows the basic predictions of marginal value theorem. In distribution tests, H. vitripennis were more abundant in the patch center than patch edges in the isolated L. indica patch, but in a patch bordering cottonwood (Populus sp.) and peach (P. persica), H. vitripennis numbers were generally higher along the edges of the patch. These data suggest that alternate hosts bordering cropping systems may be important to the spatial dynamics of H. vitripennis. Implications of these spatial observations on the biology of H. vitripennis and potential control methods are discussed.

  3. Enamel pretreatment with Er:YAG laser: effects on the microleakage of fissure sealant in fluorosed teeth

    PubMed Central

    Kianimanesh, Nasrin; Shayeghi, Bahareh

    2014-01-01

    Objectives The purpose of this in vitro study was to evaluate the microleakage and penetration of fissure sealant in permanent molar teeth with fluorosis after pretreatment of the occlusal surface. Materials and Methods A total of 120 third molars with mild dental fluorosis were randomly divided into 6 groups (n = 20). The tooth surfaces were sealed with an unfilled resin fissure sealant (FS) material. The experimental groups included: 1) phosphoric acid etching (AE) + FS (control); 2) AE + One-Step Plus (OS, Bisco) + FS; 3) bur + AE + FS; 4) bur + AE + OS + FS; 5) Er:YAG laser + AE + FS; and 6) Er:YAG laser + AE + OS + FS. After thermocycling, the teeth were immersed in 0.5% fuchsin and sectioned. Proportions of mircoleakage (PM) and unfilled area (PUA) were measured by digital microscope. Results Overall, there were significant differences among all groups in the PM (p = 0.00). Group 3 showed the greatest PM, and was significantly different from groups 2 to 6 (p < 0.05). Group 6 showed the lowest PM. Pretreatment with Er:YAG with or without adhesive led to less PM than bur pretreatment. There were no significant differences among groups in PUA. Conclusions Conventional acid etching provided a similar degree of occlusal seal in teeth with fluorosis compared to those pretreated with a bur or Er:YAG laser. Pretreatment of pits and fissures with Er:YAG in teeth with fluorosis may be an alternative method before fissure sealant application. PMID:25110641

  4. Determination of aromatic hydrocarbons in bituminous emulsion sealants using headspace solid-phase microextraction and gas chromatography-mass spectrometry.

    PubMed

    Tang, Bing; Isacsson, Ulf

    2006-12-22

    The possibility of quantitative determination of aromatic hydrocarbons in bituminous emulsion sealants was investigated using headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS). The target analytes studied were benzene, toluene, ethylbenzene, p-, m-, and o-xylene (BTEX) as well as 1,3,5- and 1,2,4-trimethylbenzene. Experimental factors influencing HS-SPME efficiency were studied (sample-headspace equilibration time, extraction time and sample matrix effects). A HS-SPME method using surrogate matrix was developed. The detection limit was estimated as approximately 0.1 ppmw for the target analytes investigated. Good linearity was observed (R(2)>0.997) for all calibration curves obtained. The repeatability of the method (RSD, relative standard deviation) was found less than 10%. The accuracy of the method given by recovery of spiked samples was between 99 and 116%. The HS-SPME method developed was applied to two commercially available bituminous emulsion sealants. External calibration and standard addition approaches were investigated, and statistical paired t-test was performed. The contents of target aromatic hydrocarbons in the sealants studied varied from approximately 0.4 to 150 ppmw. The method developed shows potential as a tool for the determination of aromatic hydrocarbons in emulsified bituminous materials.

  5. Multimode Broad-Band Patch Antennas

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R.

    2003-01-01

    Microstrip patch antennas of a proposed type would be tunable over broad wavelength ranges. These antennas would be attractive for use in a variety of microwave communication systems in which there are requirements for transmission and/or reception at multiple, widely separated frequencies. Prior efforts to construct tunable microstrip patch antennas have involved integration of microstrip circuitry with, variously, ferrite films with magneticfield tuning, solid-state electronic tuning devices, or piezoelectric tuning actuators. Those efforts have been somewhat successful, but have yielded tuning ranges of 20 percent and smaller much smaller than needed in typical practical cases. Like prior microstrip patch antennas (both tunable and non-tunable), the proposed antennas would have instantaneous bandwidths of about 1 percent of their nominal or resonance frequencies. However, these would be tunable over much broader frequency ranges as much as several octaves, depending on specific designs. They could be fabricated relatively simply and inexpensively by use of conventional photolithography, and without need for integration with solid-state electronic or piezoelectric control devices. An antenna as proposed (see figure) would include a microstrip patch radiating element on a thin ferroelectric film on a semiconductor substrate with a ground-plane conductor on the underside of the substrate. The ferroelectric film could be, for example, SrTiO3 with a thickness of the order of 1 or 2 micrometers.

  6. Juno Microwave Radiometer Patch Array Antennas

    NASA Technical Reports Server (NTRS)

    Chamberlain, N.; Chen, J.; Focardi, P.; Hodges, R.; Hughes, R.; Jakoboski, J.; Venkatesan, J.; Zawadzki, M.

    2009-01-01

    Juno is a mission in the NASA New Frontiers Program with the goal of significantly improving our understanding of the formation and structure of Jupiter. This paper discusses the modeling and measurement of the two patch array antennas. An overview of the antenna architecture, design and development at JPL is provided, along with estimates of performance and the results of measurements.

  7. Soil, Seeds, and the Pumpkin Patch!

    ERIC Educational Resources Information Center

    Phillips, Marianne; Vowell, Julie

    2013-01-01

    "Soil, Seeds, and the Pumpkin Patch!" is an integrated unit designed to provide elementary school teachers with ideas for using hands-on activities, fostering inquiry and valuable discussion, and using technology as a learning tool. This unit integrates science with language arts, mathematics, literature, and technology. During this unit, students…

  8. Analgesic Microneedle Patch for Neuropathic Pain Therapy.

    PubMed

    Xie, Xi; Pascual, Conrado; Lieu, Christopher; Oh, Seajin; Wang, Ji; Zou, Bende; Xie, Julian; Li, Zhaohui; Xie, James; Yeomans, David C; Wu, Mei X; Xie, Xinmin Simon

    2017-01-24

    Neuropathic pain caused by nerve injury is debilitating and difficult to treat. Current systemic pharmacological therapeutics for neuropathic pain produce limited pain relief and have undesirable side effects, while current local anesthetics tend to nonspecifically block both sensory and motor functions. Calcitonin gene related peptide (CGRP), a neuropeptide released from sensory nerve endings, appears to play a significant role in chronic neuropathic pain. In this study, an analgesic microneedle (AMN) patch was developed using dissolvable microneedles to transdermally deliver selective CGRP antagonist peptide in a painless manner for the treatment of localized neuropathic pain. Local analgesic effects were evaluated in rats by testing behavioral pain sensitivity in response to thermal and mechanical stimuli using neuropathic pain models such as spared-nerve injury and diabetic neuropathy pain, as well as neurogenic inflammatory pain model induced by ultraviolet B (UVB) radiation. Unlike several conventional therapies, the AMN patches produced effective analgesia on neuropathic pain without disturbing the normal nociception and motor function of the rat, resulting from the high specificity of the delivered peptide against CGRP receptors. The AMN patches did not cause skin irritation or systemic side effects. These results demonstrate that dissolvable microneedle patches delivering CGRP antagonist peptide provide an effective, safe, and simple approach to mitigate neuropathic pain with significant advantages over current treatments.

  9. A Practical Guide to Patch Testing.

    PubMed

    Fonacier, Luz

    2015-01-01

    Contact dermatitis is a common disease seen by allergists, dermatologists, and primary care physicians. The gold standard for diagnosing allergic contact dermatitis (ACD) is patch testing and is indicated in any patient with a chronic, pruritic, eczematous, or lichenified dermatitis if underlying or secondary ACD is suspected. Patients with acute generalized dermatitis who have extensive eczema on the back, are on immunosuppressant medications, and have applied topical corticosteroids, topical calcineurin inhibitors, or ultraviolet radiation to the patch test (PT) site may have suppressed PT reactions. The procedure of patch testing is not a difficult one to perform, but the interpretation of the PT needs some critical components, including having an appropriate level of suspicion for the diagnosis of ACD, testing the relevant allergens in their proper vehicle and concentration, and the necessary experience to properly interpret the results. Careful history and physical examination must be correlated with the result of the PT to establish clinical relevance. Once the PT is completed, allergens are identified, and relevance has been established, educating the patient about the avoidance of exposure is critical. The Joint Task Force of the American Academy of Allergy, Asthma and Immunology and American College of Allergy, Asthma and Immunology has developed updated practice parameters for contact dermatitis and patch testing, and their recommendations will be discussed (Fonacier LF, Bernstein DI, Pacheco K, Holness DL. Contact dermatitis: a practice parameter update 2015. J Allergy Clin Immunol Pract 2015; 3(3S):S1-S40.).

  10. Clinical evaluations of autologous fibrin glue and polyglycolic acid sheets as oral surgical wound coverings after partial glossectomy.

    PubMed

    Kouketsu, Atsumu; Nogami, Shinnosuke; Fujiwara, Minami; Mori, Shiro; Yamauchi, Kensuke; Hashimoto, Wataru; Miyashita, Hitoshi; Kurihara, Jun; Kawai, Tadashi; Higuchi, Keisuke; Takahashi, Tetsu

    2016-08-01

    Polyglycolic acid (PGA) sheets and commercial fibrin glue are commonly used to cover open wound surfaces in oral surgery. Compared to commercial fibrin glue composed of pooled allogeneic blood, autologous fibrin glue is less expensive and poses lower risks of viral infection and allergic reaction. Here, we evaluated postoperative pain, scar contracture, ingestion, tongue dyskinesia, and postoperative bleeding in 24 patients who underwent partial glossectomy plus the application of a PGA sheet and an autologous fibrin glue covering (autologous group) versus 11 patients in whom a PGA sheet and commercial fibrin glue were used (allogeneic group). The evaluated clinical measures were nearly identical in both groups. Remarkable wound surface granulation was recognized in two cases in the autologous group. No complications were observed in either group, including viral infection or allergic reaction. Abnormal postoperative bleeding in the wound region was observed in one case in the allogeneic group. Coagulation and adhesion of the autologous fibrin glue were equivalent to those of conventional therapy with a PGA sheet and commercial fibrin glue. Thus, our results show that covering wounds with autologous fibrin glue and PGA sheets may help avoid the risks of viral infection and allergic reaction in partial glossectomy cases.

  11. Whole-GUV patch-clamping.

    PubMed

    Garten, Matthias; Mosgaard, Lars D; Bornschlögl, Thomas; Dieudonné, Stéphane; Bassereau, Patricia; Toombes, Gilman E S

    2017-01-10

    Studying how the membrane modulates ion channel and transporter activity is challenging because cells actively regulate membrane properties, whereas existing in vitro systems have limitations, such as residual solvent and unphysiologically high membrane tension. Cell-sized giant unilamellar vesicles (GUVs) would be ideal for in vitro electrophysiology, but efforts to measure the membrane current of intact GUVs have been unsuccessful. In this work, two challenges for obtaining the "whole-GUV" patch-clamp configuration were identified and resolved. First, unless the patch pipette and GUV pressures are precisely matched in the GUV-attached configuration, breaking the patch membrane also ruptures the GUV. Second, GUVs shrink irreversibly because the membrane/glass adhesion creating the high-resistance seal (>1 GΩ) continuously pulls membrane into the pipette. In contrast, for cell-derived giant plasma membrane vesicles (GPMVs), breaking the patch membrane allows the GPMV contents to passivate the pipette surface, thereby dynamically blocking membrane spreading in the whole-GMPV mode. To mimic this dynamic passivation mechanism, beta-casein was encapsulated into GUVs, yielding a stable, high-resistance, whole-GUV configuration for a range of membrane compositions. Specific membrane capacitance measurements confirmed that the membranes were truly solvent-free and that membrane tension could be controlled over a physiological range. Finally, the potential for ion transport studies was tested using the model ion channel, gramicidin, and voltage-clamp fluorometry measurements were performed with a voltage-dependent fluorophore/quencher pair. Whole-GUV patch-clamping allows ion transport and other voltage-dependent processes to be studied while controlling membrane composition, tension, and shape.

  12. Surface patterning of nanoparticles with polymer patches

    DOE PAGES

    Choueiri, Rachelle M.; Galati, Elizabeth; Thérien-Aubin, Héloïse; ...

    2016-08-24

    Patterning of colloidal particles with chemically or topographically distinct surface domains (patches) has attracted intense research interest. Surface-patterned particles act as colloidal analogues of atoms and molecules serve as model systems in studies of phase transitions in liquid systems, behave as ‘colloidal surfactants’ and function as templates for the synthesis of hybrid particles. The generation of micrometre- and submicrometre-sized patchy colloids is now efficient but surface patterning of inorganic colloidal nanoparticles with dimensions of the order of tens of nanometres is uncommon. Such nanoparticles exhibit size- and shape-dependent optical, electronic and magnetic properties, and their assemblies show new collective properties.more » At present, nanoparticle patterning is limited to the generation of two-patch nanoparticles and nanoparticles with surface ripples or a ‘raspberry’ surface morphology. We demonstrate nanoparticle surface patterning, which utilizes thermodynamically driven segregation of polymer ligands from a uniform polymer brush into surface-pinned micelles following a change in solvent quality. Patch formation is reversible but can be permanently preserved using a photocrosslinking step. The methodology offers the ability to control the dimensions of patches, their spatial distribution and the number of patches per nanoparticle, in agreement with a theoretical model. The versatility of the strategy is demonstrated by patterning nanoparticles with different dimensions, shapes and compositions, tethered with various types of polymers and subjected to different external stimuli. Furthermore, these patchy nanocolloids have potential applications in fundamental research, the self-assembly of nanomaterials, diagnostics, sensing and colloidal stabilization.« less

  13. Surface patterning of nanoparticles with polymer patches

    PubMed Central

    Choueiri, Rachelle M.; Galati, Elizabeth; Thérien-Aubin, Héloïse; Klinkova, Anna; Larin, Egor M.; Querejeta-Fernández, Ana; Han, Lili; Xin, Huolin L.; Gang, Oleg; Zhulina, Ekaterina B.; Rubinstein, Michael; Kumacheva, Eugenia

    2016-01-01

    Patterning of colloidal particles with chemically or topographically distinct surface domains (patches) has attracted intense research interest1–3. Surface-patterned particles act as colloidal analogues of atoms and molecules4,5, serve as model systems in studies of phase transitions in liquid systems6, behave as ‘colloidal surfactants’7 and function as templates for the synthesis of hybrid particles8. The generation of micrometre- and submicrometre-sized patchy colloids is now efficient9–11, but surface patterning of inorganic colloidal nanoparticles with dimensions of the order of tens of nanometres is uncommon. Such nanoparticles exhibit size- and shape-dependent optical, electronic and magnetic properties, and their assemblies show new collective properties12. At present, nanoparticle patterning is limited to the generation of two-patch nanoparticles13–15, and nanoparticles with surface ripples16 or a ‘raspberry’ surface morphology17. Here we demonstrate nanoparticle surface patterning, which utilizes thermodynamically driven segregation of polymer ligands from a uniform polymer brush into surface-pinned micelles following a change in solvent quality. Patch formation is reversible but can be permanently preserved using a photocrosslinking step. The methodology offers the ability to control the dimensions of patches, their spatial distribution and the number of patches per nanoparticle, in agreement with a theoretical model. The versatility of the strategy is demonstrated by patterning nanoparticles with different dimensions, shapes and compositions, tethered with various types of polymers and subjected to different external stimuli. These patchy nanocolloids have potential applications in fundamental research, the self-assembly of nanomaterials, diagnostics, sensing and colloidal stabilization. PMID:27556943

  14. [Results of fibrin clot application for acceleration of regeneration of the damaged mandible in experiment].

    PubMed

    Maĭborodin, I V; Kolesnikov, I S; Shevela, A I; Sheplev, B V; Drovosekov, M N; Toder, M S

    2011-01-01

    The processes of regeneration of the damaged rat bottom jaw bone after application of enriched thrombocytes a fibrin clot were studied by morphological and radiovisiographic methods. At a natural course of regeneration the artificial aperture of bone was filled with blood and there the blood clot was formed. After 1 week the separate bone islets of a young tissue occurred in bone defect. In 2-3 weeks the aperture in a bottom jaw bone was completely closed by a young bone tissue. After operation with filling of bone bottom jaw defect by fibrin clot there was no formation of a blood clot. Already after 1 week the bone tissue defect was filled by the merged islets of again generated bone. By second week after fibrin use the further formation of bone tissue in defect and formation of a bone callosity was noted.

  15. Understanding patch departure rules for large carnivores: lion movements support a patch-disturbance hypothesis.

    PubMed

    Valeix, Marion; Chamaillé-Jammes, Simon; Loveridge, Andrew J; Davidson, Zeke; Hunt, Jane E; Madzikanda, Hillary; Macdonald, David W

    2011-08-01

    We test two hypotheses that could account for patch departure by large mammalian carnivores. One hypothesis is the unsuccessful-hunt hypothesis, where carnivores leave an area after an unsuccessful hunt but continue hunting in the same area after a successful hunt. The second hypothesis is the patch-disturbance hypothesis, where carnivores depart the area after a successful hunt because of behavioral responses of prey to predator presence. We used global positioning system collars to monitor the movements of African lions (Panthera leo) and identified their kill sites to distinguish between these two hypotheses. Lions moved to a different area (≥ 5 km away) after 87% of the kills, which supports the patch-disturbance hypothesis for patch-departure behavior of large mammalian carnivores.

  16. 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.

  17. Adhesive arachnoiditis after percutaneous fibrin glue treatment of a sacral meningeal cyst.

    PubMed

    Hayashi, Kazunori; Nagano, Junji; Hattori, Satoshi

    2014-06-01

    The authors present the case of a 64-year-old woman who was referred for severe sacral pain. She reported that her pain had been longstanding, and had greatly increased after percutaneous fibrin glue placement therapy for a sacral meningeal cyst 2 months earlier at a different hospital. An MRI scan obtained immediately after fibrin glue placement at that hospital suggested that fibrin glue had migrated superiorly into the subarachnoid space from the sacral cyst to the level of L-4. On admission to the authors' institution, physical examination demonstrated no abnormal findings except for perianal hypesthesia. An MRI study obtained at admission demonstrated a cystic lesion in the peridural space from the level of S-2 to S-4. Inhomogeneous intensity was identified in this region on T2-weighted images. Because the cauda equina and nerve roots appeared to be compressed by the lesion, total cyst excision was performed. The cyst cavity was filled with fluid that resembled CSF, plus gelatinous material. Histopathological examination revealed that the cyst wall was composed of hyaline connective tissue with some calcification. No nervous tissue or ganglion cells were found in the tissue. The gelatinous material was acellular, and appeared to be degenerated fibrin glue. Sacral pain persisted to some extent after surgery. The authors presumed that migrated fibrin glue caused the development of adhesive arachnoiditis. The risk of adhesive arachnoiditis should be considered when this therapy is planned. Communication between a cyst and the subarachnoid space should be confirmed to be sufficiently narrow to prevent the migration of injected fibrin glue.

  18. Non-Recurrence Complications of Fibrin Glue Use in Pterygium Surgery: Prevention and Management

    PubMed Central

    Hüseyin Cagatay, Halil; Gökçe, Gökçen; Mete, Alper; Koban, Yaran; Ekinci, Metin

    2015-01-01

    Purpose : To present complications of using fibrin glue in conjunctival-limbal autografting in pterygium surgeries other than recurrences and discuss their prevention and management strategies. Materials and Methodology: The charts of all patients who underwent fibrin glue assisted pterygium excision surgery with conjunctival-limbal autograft transplantation from 2010 to 2013 were reviewed. Patients who developed complications except recurrence postoperatively were included in this study. Results : Sixteen (17.39%) of the 92 patients were detected with a complication. Graft dehiscence was diagnosed in 7 (7.6%) patients with 5 of them treated conservatively and 2 patients requiring suturing. Five (5.43%) patients were diagnosed with cyst formation between the graft and conjunctiva or in the graft-removal area; these cysts were primarily excised and no additional problems occurred. Corneal dellen developed in 3 (3.26%) patients and 2 of them regressed after cessation of topical steroids and application of lubricant therapy while one was treated with amniotic membrane transplantation. Residual fibrin glue particles had stiffened on the ocular surface, which resulted in intensive pain and irritation in one (1.08%) patient on the same day of the surgery. The patient’s complaints were reduced by removing these particles from the ocular surface under topical anesthesia. Conclusion : Complications in fibrin glue assisted pterygium surgery are relatively different from other techniques. To avoid potential complications of fibrin glue in pterygium surgery, peroperatively ophthalmologists should ensure the conjunctival autograft and conjunctiva are properly adhered, fibrin glue remnants are completely removed from the ocular surface, and no Tenon’s capsule remains between the graft and the conjunctiva. PMID:26862358

  19. Free Fatty Acids Modulate Thrombin Mediated Fibrin Generation Resulting in Less Stable Clots

    PubMed Central

    Tanka-Salamon, Anna; Komorowicz, Erzsébet; Szabó, László; Tenekedjiev, Kiril

    2016-01-01

    Upon platelet activation, free fatty acids are released at the stage of thrombus formation, but their effects on fibrin formation are largely unexplored. Our objective was to characterize the kinetic effects of fatty acids on thrombin activity, as well as the structural and mechanical properties of the resultant fibrin clots. Thrombin activity on fibrinogen was followed by turbidimetry and detailed kinetic characterization was performed using a fluorogenic short peptide substrate. The viscoelastic properties of fibrin were measured with rotatory oscillation rheometer, whereas its structure was analyzed with scanning electron microscopy (SEM). In turbidimetric assays of fibrin generation, oleate and stearate at physiologically relevant concentrations (60–600 μM) produced a bell-shaped inhibitory dose response, increasing 10- to 30-fold the time to half-maximal clotting. Oleate inhibited thrombin activity on a short peptide substrate according to a mixed-type inhibitor pattern (a 9-fold increase of the Michaelis constant, Km and a 20% decrease of the catalytic constant), whereas stearate resulted in only a minor (15%) drop in the catalytic constant without any change in the Km. Morphometric analysis of SEM images showed a 73% increase in the median fiber diameter in the presence of stearate and a 20% decrease in the presence of oleate. Concerning the viscoelastic parameters of the clots, storage and loss moduli, maximal viscosity and critical shear stress decreased by 32–65% in the presence of oleate or stearate, but loss tangent did not change indicating decreased rigidity, higher deformability and decreased internal resistance to shear stress. Our study provides evidence that free fatty acids (at concentrations comparable to those reported in thrombi) reduce the mechanical stability of fibrin through modulation of thrombin activity and the pattern of fibrin assembly. PMID:27942000

  20. Enhancing Osteoconductivity of Fibrin Gels with Apatite-Coated Polymer Microspheres

    PubMed Central

    Davis, Hillary E.; Binder, Bernard Y.K.; Schaecher, Phillip; Yakoobinsky, Dana D.; Bhat, Archana

    2013-01-01

    Fibrin gels are a promising material for use in promoting bone repair and regeneration due to their ease of implant formation, tailorability, biocompatibility, and degradation by natural processes. However, these materials lack necessary osteoconductivity to nucleate calcium, integrate with surrounding bone, and promote bone formation. Polymeric substrata formed from poly(lactide-co-glycolide) (PLG) are widely used in bone tissue engineering. A carbonated apatite layer of bone-like mineral can be successfully grown on the surface of PLG microspheres after a multiday incubation process in modified simulated body fluid. Such coatings improve the osteoconductivity of the polymer, provide nucleation sites for cell-secreted calcium, and enhance the potential osseointegration with host tissue. We examined the capacity of mineralized polymeric microspheres suspended within fibrin hydrogels to enhance the osteoconductivity of fibrin gels and increase the osteogenic potential of these materials. The inclusion of microparticles, both nonmineralized and mineralized, reduced the capacity of mesenchymal stem cells (MSCs) to contract the gel. When cultured in osteogenic media, we detected a near linear increase in both calcium and phosphate incorporation in gels containing mineralized microspheres and entrapped MSCs. The osteoconductivity of acellular fibrin gels with mineralized and nonmineralized microspheres was assessed in a rodent calvarial bone defect over 12 weeks. Compared to untreated rodent calvarial bone defects, we detected significant increases in early vascularization when treated with fibrin gels, with greater vascularization, on average, occurring with gels containing microspheres. We detected a trend for increased bone mineral density in gels containing mineralized microspheres after 12 weeks. These findings demonstrate that the osteoconductivity of fibrin gels can be increased by inclusion of mineralized microspheres, but additional signals may be required to

  1. Interaction of fibrin with red blood cells: the role of iron.

    PubMed

    Lipinski, Boguslaw; Pretorius, Etheresia; Oberholzer, Hester M; van der Spuy, Wendy J

    2012-04-01

    Activation of coagulation pathways results in the formation of hemostatic fibrin plugs. Under normal physiologic conditions fibrin clots are gradually, albeit completely, degraded by a fibrinolytic enzyme system to ensure proper wound healing and/or blood vessel patency. Yet in pathological situations, thrombi are not effectively removed, leading to chronic thrombosis. The susceptibility of blood clots to enzymatic degradation depends on the structure and properties of fibrin fibers. Many factors have been suspected as culprits, including red blood cells (RBCs) that become transiently trapped within fibrin mesh. Here, the authors show that there is indeed a specific interaction between RBCs and fibrin-like fibers identified here as dense matted deposits (DMDs) by means of scanning electron microscopy (SEM). It is emphasized that such interactions can be observed in ischemic stroke patients, but not from healthy subjects. However, DMD/RBC aggregates can be induced in normal blood by the additions of trivalent iron ions. The plausible mechanism of the enhanced fibrin-red blood cell interaction is based on the previously described iron-induced generation of hydroxyl radicals. These radicals cause, in turn, non-enzymatic formation of fibrinogen aggregates remarkably resistant to fibrinolysis that are also similar to DMDs described in this paper. In conclusion, this relatively simple SEM analysis may become a convenient tool for diagnosing prothrombotic conditions associated with iron overload. It is suggested that future research on prevention and treatment of ischemic stroke and other thrombosis associated diseases should include testing of iron-chelating and hydroxyl radical-scavenging agents.

  2. 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

  3. A Novel Miniaturization Technique of a Microstrip Patch Antenna using Patch Resonators

    NASA Astrophysics Data System (ADS)

    Kakita, Katsutoshi; Morita, Norihiko; Horii, Yasushi

    Microstrip patch antennas have been widely used in mobile and satellite communication systems due to their great advantages of low cost, low profile, lightweight and easy fabrication. However, the dimensions of a classical patch antenna are on the order of half a wavelength. This paper proposes a new approach to reduce the size of the antenna by embedding several patch resonators in an antenna substrate. Periodically installed resonators are expected to exhibit slow-wave effects. First of all, a microstrip delay line having a train of patch resonators in its substrate is demonstrated theoretically by the conventional FDTD method, and the slow-wave effect is discussed. Next, a 2-dimentional patch resonator array is applied to a microstrip patch antenna, and the effectiveness of the proposed structure is evaluated in the respect of antenna dimensions. Also, several experiments have been carried out to confirm the theoretical predictions. Using a prototype model fabricated on an LTCC substrate, the size reduction of more the 50% is attained.

  4. Malfunction of dialysis catheters: management of fibrin sheath and related problems.

    PubMed

    Faintuch, Salao; Salazar, G M M

    2008-09-01

    Suitable central venous access for hemodialysis is frequently required in patients with end-stage renal disease, whenever an arteriovenous fistula or peritoneal dialysis fails or is not a possibility. Ultimately, long-term dialysis via central access may result in dysfunctional catheter with problems such as malpositioning of catheter tip, fibrin sheath formation, thrombosis, infection, and bleeding. The role of interventional radiology is to deliver appropriate treatment to maintain patent and functional access, while minimizing the risk of venous occlusive disease. This article aims at describing different techniques and approaches for management of fibrin sheath associated with malfunctioning tunneled dialysis catheters, as well as to provide scientific evidence from the current literature.

  5. Acute Fibrinous and Organizing Pneumonia with Myelodysplastic Syndrome: Corticosteroid Monotherapy Led to Successful Ventilator Weaning

    PubMed Central

    Yamamoto, Mari; Murata, Kengo; Kiriu, Takahiro; Kouzai, Yasuji; Takamori, Mikio

    2016-01-01

    A 62-year-old man with myelodysplastic syndrome (MDS) presented to our hospital with a high fever. Although treatment with broad-spectrum antibiotics was initiated, his respiratory status worsened to the point that he required mechanical ventilation. However, he was successfully treated with a corticosteroid without immunosuppression. Sequential transbronchial lung biopsies revealed abundant fibrin exudate in the alveolar spaces, which was subsequently replaced by fibroblasts, showing that acute fibrinous and organizing pneumonia (AFOP) gradually changes into organizing pneumonia. Our case demonstrated both the efficacy of corticosteroid-monotherapy and the histological course of AFOP. PMID:27803411

  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. Nitrogenous subcutaneous emphysema caused by spray application of fibrin glue during retroperitoneal laparoscopic surgery.

    PubMed

    Matsuse, Shinji; Maruyama, Atsushi; Hara, Yoshiki

    2011-06-01

    We report a case of a patient treated by retroperitoneoscopic partial nephrectomy who developed nitrogenous subcutaneous emphysema (SCE) as a complication. The use of a nitrogen gas-pressured fibrin tissue adhesive applied as a spray caused excessively increased pressure in the closed retroperitoneal space and resulted in widespread SCE with protracted clinical course. To the best of our knowledge, this is the first report of nitrogenous SCE associated with pneumoperitoneum. The clinical significance of nitrogenous SCE is emphasized, and the risks associated with the use of fibrin glue as a spray during laparoscopic surgery are discussed.

  8. NORTHWEST OBLIQUE AERIAL VIEW OF FORT DELAWARE AND PEA PATCH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTHWEST OBLIQUE AERIAL VIEW OF FORT DELAWARE AND PEA PATCH ISLAND. REMAINS OF SEA WALL VISIBLE IN FOREGROUND AND RIGHT OF IMAGE - Fort Delaware, Pea Patch Island, Delaware City, New Castle County, DE

  9. Performance Analysis of Coaxial Fed Stacked Patch Antennas

    NASA Astrophysics Data System (ADS)

    Jain, Satish K.; Jain, Shobha

    2014-01-01

    A performance analysis of coaxial fed stacked dual patch electromagnetic-coupled microstrip antenna useful for satellite communication working in X/Ku band is presented. A simplified structure of stacked dual patch antenna is proposed with adjustable foam-gap between patches. Few important geometrical parameters were chosen on which the performance of stacked dual patch antenna mainly depends. Dimension of lower square patch, upper square patch and height of foam-gap between two patches are the parameters, which were varied one by one keeping other parameters constant. The performance was observed through the reflection coefficient (dB) and smith chart impedance plot, obtained from the numerical simulator (IE3D) for the dual resonance frequency and bandwidth. Proposed geometry of stacked dual patch antenna was also analyzed with cavity model and artificial neural network modeling technique. Dual resonance frequencies and associated bandwidth were calculated through them and results were cross checked in the laboratory with a few experimental findings.

  10. [Responses of Caragana seed pests to host plant patch quality and patch pattern in desert regions of Ningxia, Northwest China].

    PubMed

    Zhang, Da-zhi; He, Da-han

    2011-07-01

    Taking the desert landscape in mid-eastern Ningxia of Northeast China as the background, eighteen patches of Caragana shrub lands (natural or manned) with the habitat types of manually-fixed sandy land, mobile sandy land, and silty-loam downland were selected as study sites to investigate the responses of three Caragana seed pest species (Kytorhinus immixtus, Etiella zinckenella, and Bruchophagus neocaraganae) to the host plant patch quality, patch area, and patch spatial pattern. The damaged rate of host plant by the pests had close relations to the patch quality, patch pattern, and the transferring capability of the pests. The responses of the pests to patch quality were affected by patch scale, and among the three habitat types, manually-fixed sandy land had the highest damaged rate, followed by mobile sandy land, and silty-loam downland, with significant differences among them (P<0.05). In small scale patch pattern, there existed definite correlations between the pest number and the patch area and its fragmentation degree. The decrease of patch area and the increase of the fragmentation degree reduced the damage rate of high transferring capability Etiella zinckenella (r = 0.365), but had less effects on low transferring capability K. immixtus (r = 0.160) and B. neocaraganae (r = 0.193). The strength of patch edge effect and the mutual complement of the resources around patches had positive effects on the population density of the pests.

  11. Evaluation of asbestos exposure within the automotive repair industry: a study involving removal of asbestos-containing body sealants and drive clutch replacement.

    PubMed

    Blake, Charles L; Dotson, G Scott; Harbison, Raymond D

    2008-12-01

    Two independent assessments were performed of airborne asbestos concentrations generated during automotive repair work on vintage vehicles . The first involved removal of asbestos-containing seam sealant, and the second involved servicing of a drive clutch. Despite the relatively high concentrations (5.6-28%) of chrysotile fibers detected within bulk samples of seam sealant, the average asbestos concentration for personal breathing zone (PBZ) samples during seam sealant removal was 0.006 f/cc (fibers/cubic centimeter of air). Many other air samples contained asbestos at or below the analytical limit of detection (LOD). Pneumatic chiseling of the sealant material during removal resulted in 69% of area air samples containing asbestos. Use of this impact tool liberated more asbestos than hand scraping. Asbestos fibers were only detected in air samples collected during the installation of a replacement clutch. The highest asbestos corrected airborne fiber concentration observed during clutch installation was 0.0028 f/cc. This value is approximately 100 times lower than Occupational Safety and Health Administration's (OSHA) permissible exposure limit (PEL) of 0.1f/cc. The airborne asbestos concentrations observed during the servicing of vintage vehicles with asbestos-containing seam sealant and clutches are comparable to levels reported for repair work involving brake components and gaskets.

  12. Corridor Length and Patch Colonization by a Butterfly, Junonia coenia

    SciTech Connect

    Haddad, N.

    1999-01-22

    Study hypothesized that corridors increase patch colonization by Junonia coenia regardless of insects initial distance from patch, as the butterfly is known to move between patches preferentially through corridors. Neither corridor nor distance had significant effect on patch colonization, but significant interaction between presence or absence of corridors and distance. One critical factor is interpatch distance which may determine the relative effectiveness of corridors and other landscape configurations.

  13. Characterization of star adhesive sealants based on PEG/dextran hydrogels.

    PubMed

    Artzi, Natalie; Shazly, Tarek; Crespo, Cristina; Ramos, Adriana Bon; Chenault, H Keith; Edelman, Elazer R

    2009-08-11

    Swellable PEG amine/dextran aldehyde composite materials are emerging as a controlled, biocompatible tissue adhesive. We explain how preservation of natural tissue amines provides biocompatibility for PEG/dextran that exceeds the stringent, destructive cyanide-based chemistry of cyanoacrylates, and adhere far better than fibrin glue. Strategic variations of material composition allow for the improvement of biocompatibility and adhesion strength. Material variations can be tailored to match the needs of specific tissue beds for an array of clinical applications. PEG/dextran cohesive properties are most responsive to variations in the PEG component (number of arms and solid content), while tissue/material adhesion strength is primarily determined by the number of aldehydes in the dextran.

  14. Novel Metamaterials for Patch Antennas Applications

    NASA Astrophysics Data System (ADS)

    Zervos, Theodore; Lazarakis, Fotis; Alexandridis, Antonis; Dangakis, Kostas; Stamopoulos, Dimosthenis; Pissas, Michalis

    In this paper we introduce the incorporation of magneto-electric materials into antenna design and the potential of controlling the behavior of the antenna by means of an external magnetic field. After an intensive study of magneto-electric material properties, a ferrimagnetic compound called Yttrium Iron Garnet (YIG) was found to be the best candidate for the novel antenna design. We provide a metamaterial patch antenna design where a part of the substrate is replaced by the YIG compound. After several design modifications the final model includes a circular-shaped YIG substrate just under the metallic patch and offers sufficient performance in terms of resonance, bandwidth and radiation efficiency. Additionally, in the presence of an external magnetic field the polarization becomes elliptical and the sense of the polarization (left or right) can be controlled through the direction of the magnetic field. That latter characteristic confirms the metamaterial-nature of the antenna.

  15. Mesh saliency with adaptive local patches

    NASA Astrophysics Data System (ADS)

    Nouri, Anass; Charrier, Christophe; Lézoray, Olivier

    2015-03-01

    3D object shapes (represented by meshes) include both areas that attract the visual attention of human observers and others less or not attractive at all. This visual attention depends on the degree of saliency exposed by these areas. In this paper, we propose a technique for detecting salient regions in meshes. To do so, we define a local surface descriptor based on local patches of adaptive size and filled with a local height field. The saliency of mesh vertices is then defined as its degree measure with edges weights computed from adaptive patch similarities. Our approach is compared to the state-of-the-art and presents competitive results. A study evaluating the influence of the parameters establishing this approach is also carried out. The strength and the stability of our approach with respect to noise and simplification are also studied.

  16. Corridor Length and Patch Colonization by a Butterfly Junonia coenia

    SciTech Connect

    Nick Haddad

    2000-06-01

    Habitat corridors have been proposed to reduce patch isolation and increase population persistence in fragmented landscapes. This study tested whether patch colonization was increased by the presence and various length corridors. The specific butterfly species tested has been shown to use corridors, however, the results indicate that neither the distance between patches or the presence of a corridor influenced colonization.

  17. Evaluation of a fissure sealant program as part of community-based teaching and training.

    PubMed

    van Wyk, Philippus J; Kroon, Jeroen; White, John G

    2004-01-01

    Since 1995 the Department of Community Dentistry of the University of Pretoria has been involved in the rendering of mobile primary oral health care services to children in the Hammanskraal area of Gauteng, South Africa, as part of their students' community-based training. Mokonyama Primary School was identified as the first school where a primary oral health care service could be rendered. The objective of this study was to evaluate the impact (outcomes) of a fissure sealant program on the dentition status of the school children. Seven years after the implementation of the program, the dentition status of children at Mokonyama was compared with that of a comparable group of children from the same area who were not exposed to the program. The results showed that the decayed, missing, and filled teeth in the primary dentition (dmft) in the six-year-old group in Mokonyama (1.74) did not differ significantly from the dmft (1.43) of the control group (p = 0.49). The decayed, missing, and filled teeth in the permanent dentition (DMFT) of 0.59 for the fifteen-year-old group in Mokonyama, however, differed significantly (p = 0.0001) from the DMFT of the control group (2.38). Fifteen-year-old children in Mokonyama had 75.2 percent fewer caries than their counterparts in the control group.

  18. Two-year follow-up in patients treated with emphysematous lung sealant for advanced emphysema.

    PubMed

    Kramer, Mordechai R; Refaely, Yael; Maimon, Nimrod; Rosengarten, Dror; Fruchter, Oren

    2013-11-01

    Endoscopic lung volume-reduction therapy for emphysema has been associated with therapeutic responses smaller in magnitude and less durable than surgical volume reduction (LVRS). Bronchoscopic emphysematous lung sealant (ELS) therapy has been shown to produce improvements in pulmonary function similar to surgery at 1 year. This case series summarizes safety and efficacy data of all patients from the initial ELS study out to 2 years. Between 1 and 2 years, there were three all-cause adverse events requiring hospitalization. One patient went on to successful lung transplant. Improvements relative to baseline in spirometry (change in FEV1: + 14.3 ± 33.1%; change in FVC: + 5.8 ± 23.2%) and diffusing capacity (change in diffusing capacity of the lung for carbon monoxide: + 10.6 ± 20.6%) were observed at 2 years. An exponential model fit to FEV₁ data at 6, 12, 18, and 24 months predicted improvements from a baseline of > 5% out to 4.1 years, similar to what has been reported following surgery. This report confirms long-term safety and efficacy following ELS therapy in advanced emphysema. Studies in a larger cohort are needed to define the role of ELS therapy in the treatment algorithm of patients with this condition.

  19. A randomised trial of lung sealant versus medical therapy for advanced emphysema.

    PubMed

    Come, Carolyn E; Kramer, Mordechai R; Dransfield, Mark T; Abu-Hijleh, Muhanned; Berkowitz, David; Bezzi, Michela; Bhatt, Surya P; Boyd, Michael B; Cases, Enrique; Chen, Alexander C; Cooper, Christopher B; Flandes, Javier; Gildea, Thomas; Gotfried, Mark; Hogarth, D Kyle; Kolandaivelu, Kumaran; Leeds, William; Liesching, Timothy; Marchetti, Nathaniel; Marquette, Charles; Mularski, Richard A; Pinto-Plata, Victor M; Pritchett, Michael A; Rafeq, Samaan; Rubio, Edmundo R; Slebos, Dirk-Jan; Stratakos, Grigoris; Sy, Alexander; Tsai, Larry W; Wahidi, Momen; Walsh, John; Wells, J Michael; Whitten, Patrick E; Yusen, Roger; Zulueta, Javier J; Criner, Gerard J; Washko, George R

    2015-09-01

    Uncontrolled pilot studies demonstrated promising results of endoscopic lung volume reduction using emphysematous lung sealant (ELS) in patients with advanced, upper lobe predominant emphysema. We aimed to evaluate the safety and efficacy of ELS in a randomised controlled setting.Patients were randomised to ELS plus medical treatment or medical treatment alone. Despite early termination for business reasons and inability to assess the primary 12-month end-point, 95 out of 300 patients were successfully randomised, providing sufficient data for 3- and 6-month analysis.57 patients (34 treatment and 23 control) had efficacy results at 3 months; 34 (21 treatment and 13 control) at 6 months. In the treatment group, 3-month lung function, dyspnoea, and quality of life improved significantly from baseline when compared to control. Improvements persisted at 6 months with >50% of treated patients experiencing clinically important improvements, including some whose lung function improved by >100%. 44% of treated patients experienced adverse events requiring hospitalisation (2.5-fold more than control, p=0.01), with two deaths in the treated cohort. Treatment responders tended to be those experiencing respiratory adverse events.Despite early termination, results show that minimally invasive ELS may be efficacious, yet significant risks (probably inflammatory) limit its current utility.

  20. Investigation of Performance of SCN-1 Pure Glass as Sealant Used in SOFC

    SciTech Connect

    Liu, Wenning N.; Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2010-03-01

    As its name implies, self-healing glass seal has the potential of restoring its mechanical properties upon being reheated to stack operating temperature, even when it has experienced some cooling induced damage/crack at room temperature. Such a self-healing feature is desirable for achieving high seal reliability during thermal cycling. On the other hand, self-healing glass is also characterized by its low mechanical stiffness and high creep rate at the typical operating temperature of SOFCs. Therefore, from a design’s perspective, it is important to know the long term geometric stability and thermal mechanical behaviors of the self-healing glass under the stack operating conditions. These predictive capabilities will guide the design and optimization of a reliable sealing system that potentially utilizes self-healing glass as well as other ceramic seal components in achieving the ultimate goal of SOFC. In this report, we focused on predicting the effects of various generic seal design parameters on the stresses in the seal. For this purpose, we take the test cell used in the leakage test for compliant glass seals conducted in PNNL as our initial modeling geometry. The effect of the ceramic stopper on the geometry stability of the self-healing glass sealants is studied first. Then we explored the effect of various interfaces such as stopper and glass, stopper and PEN, as well stopper and IC plate, on the geometry stability and reliability of glass during the operating and cooling processes.