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Sample records for fibrin sealant patch

  1. Novel Technique Using Polyester Fabric and Fibrin Sealant Patch for Acute Aortic Dissection.

    PubMed

    Ohira, Suguru; Fukumoto, Atsushi; Matsushiro, Takuya; Yaku, Hitoshi

    2016-08-01

    We describe a simple and effective technique for acute aortic dissection using a combination of polyester fabric and a fibrin sealant patch (FSP) to achieve effective reinforcement and haemostasis of the aortic stump. Firstly, the 0.61mm thick knitted polyester fabric sheet was cut to half of the size of the FSP. Next, fibrin glue was sprayed onto the collagen layer of the FSP. Subsequently, a fabric sheet was placed upon it, and the FSP was put together with the irrigated collagen layer, and then completely dried to bind the patch. As a result, the dry fibrinogen/thrombin layers, as an adhesive surface, faced outward. This patch was trimmed to a 10-15-mm-wide strip. The composite patch was inserted into the false lumen. The stump was gently pressed to fix the aortic intima and adventitia. There are several advantages: the combined patch can be prepared during systemic cooling, and therefore can minimise the circulatory arrest time; secondly, the false lumen is not directly exposed to fibrin glue and so the risk of embolism is extremely low; thirdly, the expected haemostatic effect is greater as FSP lines the exterior of the intima, achieving haemostasis for suture holes. PMID:27011040

  2. 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

  3. 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

  4. Fibrin sealant use in pilonidal sinus: Systematic review

    PubMed Central

    Kayaalp, Cuneyt; Ertugrul, Ismail; Tolan, Kerem; Sumer, Fatih

    2016-01-01

    AIM: To review the current data about the success rates of fibrin sealant use in pilonidal disease. METHODS: Fibrin sealant can be used for different purposes in pilonidal sinus treatment, such as filling in the sinus tracts, covering the open wound after excision and lay-open treatment, or obliterating the subcutaneous dead space before skin closure. We searched Pubmed, Google-Scholar, Ebsco-Host, clinicaltrials, and Cochrane databases and found nine studies eligible for analysis; these studies included a total of 217 patients (84% male, mean age 24.2 ± 7.8). RESULTS: In cases where fibrin sealant was used to obliterate the subcutaneous dead space, there was no reduction in wound complication rates (9.8% vs 14.6%, P = 0.48). In cases where sealant was used to cover the laid-open area, the wound healing time and patient comfort were reported better than in previous studies (mean 17 d, 88% satisfaction). When fibrin sealant was used to fill the sinus tracts, the recurrence rate was around 20%, despite the highly selected grouping of patients. CONCLUSION: Consequently, using fibrin sealant to decrease the risk of seroma formation was determined to be an ineffective course of action. It was not advisable to fill the sinus tracts with fibrin sealant because it was not superior to other cost-effective and minimally invasive treatments. New comparative studies can be conducted to confirm the results of sealant use in covering the laid-open area. PMID:27022454

  5. Closing microvascular lesions with fibrin sealant-attached muscle pads.

    PubMed

    Fehm, Nando Percy; Vatankhah, Bijan; Dittmar, Michael S; Tevetoglu, Yesim; Retzl, Gerald; Horn, Markus

    2005-01-01

    Fibrin sealants are used in a variety of surgical procedures, mainly for purposes of hemostasis and assisted wound healing. The combined use of fibrin sealant and autologous muscle pads for hemostasis was not reported previously. Arterial incisions in the common carotid artery in rats were closed by the combined application of fibrin sealant and an autologous muscle pad. Postsurgical vessel patency and degree of stenosis were evaluated by color duplex sonography, computed tomography angiography, and postmortem histology. The combined application of muscle pad and fibrin sealant and achievement of hemostasis was feasible in all animals. Seventy-eight percent of animals showed no or only slight postsurgical vessel stenosis. Our method is simple and quick to perform, showing a high potential for hemostasis in microvascular lesions. Therefore, it might be used in future experimental studies for conservation of vessel patency after arterial catheterization and in experimental or clinical vascular surgery. PMID:16184526

  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. Our experience of fibrin sealant-assisted implantation of Ahmed glaucoma valve

    PubMed Central

    Choudhari, Nikhil S; Neog, Aditya; Sharma, Anuj; Iyer, Geetha K; Srinivasan, Bhaskar

    2013-01-01

    Aim: To report our experience with the fibrin sealant as a suture substitute for securing the human scleral patch graft during implantation of Ahmed glaucoma valve (AGV). Materials and Methods: A retrospective, non-comparative study of 12 eyes of 12 patients who underwent an AGV implantation with fibrin sealant for part of the procedure during June 2009 to September 2010. Results: The mean patient age was 21.5 ± 20.6 years. Male: Female ratio was 2 : 1. Seven (58.3%) patients were monocular. The indications for AGV were varied. The mean number of intra-ocular surgeries prior to an implantation of AGV was 1.8. The mean follow-up duration was 24.5 ± 17.9 weeks. There was a statistically significant reduction in the mean IOP and in the mean number of anti-glaucoma medications at the final visit compared to the pre-operative values (P < 0.01, paired t test). Conjunctival retraction was seen in 1 (8.3%) case. The scleral patch graft was retracted posteriorly in another (8.3%) case. There was no case of AGV tube exposure, tube-cornea touch, or conjunctival erosion. Vision threatening complication viz. late post-operative rhegmatogenous retinal detachment, unlikely to be related to the use of the fibrin sealant, occurred in 2 (16.6%) eyes. Conclusion: The fibrin sealant offers the advantages of safety and convenience to the placement of a scleral patch graft during an AGV implantation. PMID:23275217

  8. Transurethral Use of Evicel® Fibrin Sealant

    PubMed Central

    Masel, Jonathan L.

    2015-01-01

    Transurethral resection of bladder tumor remains the most common procedure for the diagnosis, management, and treatment of bladder cancer. Deep resection of the detrusor muscle for the correct staging of bladder cancer can increase the risk of hemorrhage that can be difficult to control with standard transurethral surgical maneuvers. Evicel® Fibrin Sealant was applied transurethrally to manage difficult hemorrhage following transurethral resection of bladder tumor in two surgically complex bladder cancer patients. Our early experience suggests Evicel® can be an effective tool in managing difficult to control hemorrhage associated with TURBT. Further clinical investigation is to be encouraged. PMID:26793564

  9. Enhancement of withstanding pressure of fibrin sealant by modified mixing ratio of fibrin sealant components for skull base reconstruction: technical note.

    PubMed

    Saitoh, Youichi; Oshino, Satoru

    2013-01-01

    A method to enhance the withstanding pressure of fibrin sealant in gasket-seal closure to prevent cerebrospinal fluid (CSF) leakage after extended transsphenoidal surgery (ETSS) was investigated by adjusting the mixing ratio of the components. A plastic chamber (200 ml) was constructed with a lid made of hydroxyapatite with a hole 10 mm in diameter. The chamber could be pressurized via an opening in the side wall. The hole in the hydroxyapatite lid was covered with a Gore-Tex sheet, 15 mm in diameter. The margin of the sheet was free. Solutions A (fibrinogen 80 mg/ml) and B (thrombin 250 units/ml) of fibrin sealant were mixed in volume ratios of 1:1, 2:1, and 5:1, and applied to the Gore-Tex sheet, then water was introduced to cover the fibrin sealant. The pressure was measured at which air leakage occurred from the side of the Gore-Tex sheet. The pressure values for A/B ratios of 1:1, 2:1, and 5:1 were 117 ± 23.8 mmH(2)O (mean ± standard error) (n = 5), 234 ± 38.8 mmH(2)O (n = 5), and 345 ± 36.4 mmH(2)O (n = 5), respectively, in the acute phase (5 minutes after application of fibrin sealant). Pressures were increased after 24 hours, and that for 5:1 was the highest (373 ± 40.4 mmH(2)O, n = 5). The use of devices such as syringes specially designed to mix solutions A and B in the ratio of 5:1 can easily enhance the preventive effect of fibrin sealant against CSF leakage in ETSS. PMID:23358175

  10. A prospective, randomized, double-blind trial of the use of fibrin sealant for face lifts.

    PubMed

    Oliver, D W; Hamilton, S A; Figle, A A; Wood, S H; Lamberty, B G

    2001-12-01

    Fibrin sealant imitates the final phase of the blood coagulation process. Fibrinogen is converted into fibrin on a tissue surface by the action of thrombin, which is then cross-linked by factor XIIIa, creating a mechanically stable fibrin network. This fibrin network is thought to reduce the amount of postoperative bleeding by sealing capillary vessels and allowing raw operative surfaces to adhere. The authors conducted a prospective, double-blind, randomized, controlled trial on the use of fibrin sealant in 20 consecutive patients undergoing bilateral face lifts by the same surgeon. Each patient was randomized for the use of fibrin sealant on either the right or the left side with the contralateral side acting as the control. Total drainage was recorded on each side for 24 hours before drains were removed. The age range of the patients in the trial (all of whom were women) was 44 to 70 years (mean, 55). The side treated with fibrin glue had a median drainage of 10 ml and the control side 30 ml. The Wilcoxon signed rank test shows a significant difference in drainage between sides (p = 0.002). The reduction in postoperative drainage could also reduce pain and bruising, increasing patient satisfaction with this procedure. The need for drains may also be obviated. PMID:11743409

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

    PubMed Central

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

    2016-01-01

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

  12. 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

  13. Long-Standing Motor and Sensory Recovery following Acute Fibrin Sealant Based Neonatal Sciatic Nerve Repair.

    PubMed

    Perussi Biscola, Natalia; Politti Cartarozzi, Luciana; Ferreira Junior, Rui Seabra; Barraviera, Benedito; Leite Rodrigues de Oliveira, Alexandre

    2016-01-01

    Brachial plexus lesion results in loss of motor and sensory function, being more harmful in the neonate. Therefore, this study evaluated neuroprotection and regeneration after neonatal peripheral nerve coaptation with fibrin sealant. Thus, P2 neonatal Lewis rats were divided into three groups: AX: sciatic nerve axotomy (SNA) without treatment; AX+FS: SNA followed by end-to-end coaptation with fibrin sealant derived from snake venom; AX+CFS: SNA followed by end-to-end coaptation with commercial fibrin sealant. Results were analyzed 4, 8, and 12 weeks after lesion. Astrogliosis, microglial reaction, and synapse preservation were evaluated by immunohistochemistry. Neuronal survival, axonal regeneration, and ultrastructural changes at ventral spinal cord were also investigated. Sensory-motor recovery was behaviorally studied. Coaptation preserved synaptic covering on lesioned motoneurons and led to neuronal survival. Reactive gliosis and microglial reaction decreased in the same groups (AX+FS, AX+CFS) at 4 weeks. Regarding axonal regeneration, coaptation allowed recovery of greater number of myelinated fibers, with improved morphometric parameters. Preservation of inhibitory synaptic terminals was accompanied by significant improvement in the motor as well as in the nociceptive recovery. Overall, the present data suggest that acute repair of neonatal peripheral nerves with fibrin sealant results in neuroprotection and regeneration of motor and sensory axons. PMID:27446617

  14. 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

  15. Autologous fibrin sealant (Vivostat®) in the neurosurgical practice: Part I: Intracranial surgical procedure

    PubMed Central

    Graziano, Francesca; Certo, Francesco; Basile, Luigi; Maugeri, Rosario; Grasso, Giovanni; Meccio, Flavia; Ganau, Mario; Iacopino, Domenico G.

    2015-01-01

    Background: Hemorrhages, cerebrospinal fluid (CSF) fistula and infections are the most challenging postoperative complications in Neurosurgery. In this study, we report our preliminary results using a fully autologous fibrin sealant agent, the Vivostat® system, in achieving hemostasis and CSF leakage repair during cranio-cerebral procedures. Methods: From January 2012 to March 2014, 77 patients were studied prospectively and data were collected and analyzed. Autologous fibrin sealant, taken from patient's blood, was prepared with the Vivostat® system and applied on the resection bed or above the dura mater to achieve hemostasis and dural sealing. The surgical technique, time to bleeding control and associated complications were recorded. Results: A total of 79 neurosurgical procedures have been performed on 77 patients. In the majority of cases (98%) the same autologous fibrin glue provided rapid hemostasis and dural sealing. No patient developed allergic reactions or systemic complications in association with its application. There were no cases of cerebral hematoma, swelling, infection, or epileptic seizures after surgery whether in the immediate or in late period follow-up. Conclusions: In this preliminary study, the easy and direct application of autologous fibrin sealant agent helped in controlling cerebral bleeding and in providing prompt and efficient dural sealing with resolution of CSF leaks. Although the use of autologous fibrin glue seems to be safe, easy, and effective, further investigations are strongly recommended to quantify real advantages and potential limitations. PMID:25984391

  16. Fibrin Sealant: A Review of the History, Biomechanics, and Current Applications for Prosthetic Fixation in Hernia Repair.

    PubMed

    Watson, Jefferson Tyler; Webb, David L; Stoikes, Nathaniel F N; Voeller, Guy R

    2015-11-01

    The role of surgical adhesives in hernia repair has continued to evolve. The purpose of this chapter is to review the role of fibrin sealant and its application in general surgery for mesh fixation, specifically the history, biomechanics, and clinical utilization. The utilization of fibrin sealant for repair of groin hernias, both open and laparoscopic, ventral hernias, and hiatal hernias will be discussed. PMID:26696538

  17. Influence of Delivery Method on Neuroprotection by Bone Marrow Mononuclear Cell Therapy following Ventral Root Reimplantation with Fibrin Sealant

    PubMed Central

    Barbizan, Roberta; Castro, Mateus V.; Barraviera, Benedito; Ferreira, Rui S.; Oliveira, Alexandre L. R.

    2014-01-01

    The present work compared the local injection of mononuclear cells to the spinal cord lateral funiculus with the alternative approach of local delivery with fibrin sealant after ventral root avulsion (VRA) and reimplantation. For that, female adult Lewis rats were divided into the following groups: avulsion only, reimplantation with fibrin sealant; root repair with fibrin sealant associated with mononuclear cells; and repair with fibrin sealant and injected mononuclear cells. Cell therapy resulted in greater survival of spinal motoneurons up to four weeks post-surgery, especially when mononuclear cells were added to the fibrin glue. Injection of mononuclear cells to the lateral funiculus yield similar results to the reimplantation alone. Additionally, mononuclear cells added to the fibrin glue increased neurotrophic factor gene transcript levels in the spinal cord ventral horn. Regarding the motor recovery, evaluated by the functional peroneal index, as well as the paw print pressure, cell treated rats performed equally well as compared to reimplanted only animals, and significantly better than the avulsion only subjects. The results herein demonstrate that mononuclear cells therapy is neuroprotective by increasing levels of brain derived neurotrophic factor (BDNF) and glial derived neurotrophic factor (GDNF). Moreover, the use of fibrin sealant mononuclear cells delivery approach gave the best and more long lasting results. PMID:25157845

  18. 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.

  19. 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

  20. The hemodynamic behavior of arterial anastomosis using fibrin sealant: experimental study in swine.

    PubMed

    Rocha, Eduardo A V; de Souza, Cláudio

    2008-11-01

    The wide use of biological sealants as a reinforcement for arterial sutures and the small experimental base in literature motivated this study. Our aim was to evaluate the flow, tear pressure, and the need of reinforcement stitches in sutured arteries after a cross-section. This research project complied with the Helsinki convention. The Tissucol (Baxter) fibrin sealant was used in all experiments. The femoral and carotid arteries of 17 swine from the same breed (weighing from 15 to 20 kg) were cross-sectioned after heparinization and subjected to anastomoses using a single continuous plane of 7-0 prolene. We worked with 68 artery samples, 34 in the treatment group and 34 in the control group. For each animal, one carotid and one femoral artery randomly received fibrin sealant with the contralateral side being used as a control. The need and the number of reinforcement stitches were recorded. Ten minutes after protamine infusion, the animals were sacrificed and the arteries were catheterized respecting 1 cm proximal and distal. The arteries were measured and placed on a flow meter to evaluate the flow rate of 10 mL of 0.9% NaCl in a 50 cm high column. The arteries were then subjected to air infusion at increasingly higher pressures (stepwise increases of 25 mm Hg), the grafts were dipped in 0.9% NaCl solution, the first air leakage was observed, and the tear pressure recorded. Data was analyzed with EpiInfo 6 data manager. The external diameters and thickness of the arteries were similar in both the treatment and control group. There was no significant difference between the groups regarding the tear pressure (P = 0.329), flow rate (P = 0.943), and the number of samples with a tear pressure above 200 mm Hg. However, the sealant reduced the number of reinforcement stitches necessary (P = 0.029). We conclude that fibrin sealant reduces the need of additional stitches; however, it does not change the tear pressure nor significantly reduces the flow. PMID:18959674

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

    PubMed

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

    2016-07-01

    Autologous fibrin gel is commonly used as a scaffold for filling defects in articular cartilage. This biomaterial can also be used as a sealant to control small hemorrhages and is especially helpful in situations where tissue reparation capacity is limited. In particular, fibrin can act as a scaffold for various cell types because it can accommodate cell migration, differentiation, and proliferation. Despite knowledge of the advantages of this biomaterial and mastery of the techniques required for its application, the durability of several types of sealant at the site of injury remains questionable. Due to the importance of such data for evaluating the quality and efficiency of fibrin gel formulations on its use as a scaffold, this study sought to analyze the heterologous fibrin sealant developed from the venom of Crotalus durissus terrificus using studies in ovine experimental models. The fibrin gel developed from the venom of this snake was shown to act as a safe, stable, and durable scaffold for up to seven days, without causing adverse side effects. Fibrin gel produced from the venom of the Crotalus durissus terrificus snake possesses many clinical and surgical uses. It presents the potential to be used as a biomaterial to help repair skin lesions or control bleeding, and it may also be used as a scaffold when applied together with various cell types. The intralesional use of the fibrin gel from the venom of this snake may improve surgical and clinical treatments in addition to being inexpensive and adequately consistent, durable, and stable. The new heterologous fibrin sealant is a scaffold candidate to cartilage repair in this study. PMID:26264444

  2. Laparoscopic intraperitoneal mesh fixation with fibrin sealant of a Spigelian hernia

    PubMed Central

    Huber, Nadine; Paschke, Stephan; Henne-Bruns, Doris; Brockschmidt, Claas

    2013-01-01

    Spigelian hernia is a rare clinical entity and has a subtle clinical presentation with vague abdominal pain, which can cause an important delay in diagnosis. Given the relatively high risk of incarceration the diagnosis of Spigelian hernia is an indication for surgical repair. Laparoscopic Spigelian mesh herniorraphy has gained recognition as an effective tension-free method and is associated with lower recurrence. Appropriate fixation techniques are however required to reduce complications such as nerve irritation, hematoma, and postoperative chronic pain. In this case report we describe a novel approach in laparoscopic mesh repair of Spigelian hernia, securing a lightweight composite mesh with fibrin sealant. This fixation seems to be a reasonable, feasible alternative to the standard tissue-penetrating mesh fixation. PMID:26504700

  3. 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. PMID:16905418

  4. 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

  5. Role of EVICEL Fibrin Sealant to Assist Hemostasis in Cranial and Spinal Epidural Space: A Neurosurgical Clinical Study.

    PubMed

    Gazzeri, Roberto; Fiore, Claudio; Galarza, Marcelo

    2015-05-01

    A variety of techniques have been used to stop venous bleeding from the cranial and spinal epidural space. These generally consist of packing with oxidized regenerated cellulose, fibrillar collagen, and so forth, and in cranial surgery, tack-up sutures. Bipolar coagulation may also be used to control bleeding from spinal venous plexus, but it may bear the risk of healthy nervous tissue injury: dissipation of heat from the tips of the bipolar forceps may induce thermal injury to adjacent neural structures. Quick and safe hemostasis reduces the duration of surgery. Efficient control of bleeding is also a prerequisite for the realization of the planned therapeutic procedure, that is, the result of surgery, and can thereby reduce perioperative morbidity. Fibrin sealant is safely used to increase hemostasis and to treat cerebrospinal leakage. Between January 2014 and March 2015, the authors used injection of fibrin sealant (EVICEL®, Johnson & Johnson Wound Management, Somerville, NJ) into the cranial and spinal epidural space to assist in hemostasis in 97 patients. EVICEL injection was used in 81 cases of cranial surgery and 16 cases of spinal surgery. When the venous bleeding continued from the epidural space after packing with classical hemostatic agents, fibrin sealant was used to stop venous bleeding. When arterial bleeding was present, fibrin sealant was not used. In all cases, the results were judged to be excellent with stoppage of epidural bleeding, or good with mild persistent oozing. During the 10-minute observation period, no patients treated with EVICEL required additional hemostatic measures. No complications related to the fibrin glue were encountered. PMID:26055033

  6. 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.

  7. Combined application of heterologous collagen and fibrin sealant for liver injuries.

    PubMed

    Jakob, H; Campbell, C D; Stemberger, A; Wriedt-Lübbe, I; Blümel, G; Replogle, R L

    1984-06-01

    Hemostasis in complex liver injuries remains a problem despite improvements in operative techniques including debridement, suturing or packing. To evaluate fibrin sealant (FS), a new biodegradable hemostatic agent in combination with porcine collagen for sealing of liver injuries, three series of experiments were performed in 132 rats. In series I, 18 rats had a 10-mm in diameter and 2-mm in depth punch defect to the left lateral lobe. In the FS group (n = 9), bleeding was treated by insertion of an FS-soaked piece of collagen of equal size which was firmly attached to a plastic disk with wire anchor. In the control group (n = 9), collagen alone was inserted. Fifteen minutes after the insertion the lobe was excised and pull-off experiments were performed with simultaneous script chart recording. There was a highly significant difference in the adhesion to the liver surface (85.6 +/- 7.1 in the FS group versus 24.8 +/- 2.6 g/cm2 in the control group, P less than 0.001). In series II, 42 anticoagulated rats (Coumadin, PT 27.5% +/- 1.3) with lobectomy or liver rupture were placed in three groups (n = 14). Group I was treated with FS, group II with FS and collagen, and group III with catgut sutures which served as controls. Fourteen days later 12 rats of group I, 13 of group II, and 7 of group III were alive yielding 85.7, 92.8, and 50% overall survival rates, P less than 0.05 groups I and II versus group III. In series III, 72 non-anticoagulated rats were treated identically to series II and examined morphologically at 1, 7, 28, and 56 days.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6374292

  8. Animal experiments on hemostasis with a collagen-fibrin tissue-adhesive sealant in the nephrostomy tract.

    PubMed

    Pfab, R; Ascherl, R; Erhardt, W; Geissdörfer, K; Stemberger, A; Blümel, G; Hartung, R

    1987-01-01

    After a median laparatomy, nephrostomy was performed on 22 porcine kidneys: puncture, dilatation and introduction of a 26-French operating sheath through the parenchyma into the renal pelvis. At the end of the operation, an 8-French nephrostomy catheter prepared with a collagen-fibrin tissue-adhesive sealant was introduced through the operating sheath and the sheath was afterwards extracted. The hemostasis in the nephrostomy tract was very good in all 22 cases. There were no complications such as wound infection or stone formation during a post-operative period of between one and 95 days. Experimental investigations showed severe bleeding in nontamponade of the nephrostomy tract, in tamponade with an 8-French nephrostomy catheter and in tamponade of the nephrostomy tract with the collagen fleece wrapped around an 8-French nephrostomy catheter but not coated with the fibrin glue. PMID:2441506

  9. 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. PMID:27497370

  10. Fibrin sealant augmentation with autologous pericranium for duraplasty after suboccipital decompression in Chiari 1 patients: A case series

    PubMed Central

    Lam, Fred C.; Penumaka, Anirudh; Chen, Clark C.; Fischer, Edwin G.; Kasper, Ekkehard M.

    2013-01-01

    Background: The Chiari 1 malformation (CM1) involves decent of the tonsils of the cerebellum through the foramen magnum. Symptomatic disease requires a posterior fossa decompression with or without an expansile duraplasty. To date, the optimal surgical treatment for CM1 has not been delineated. The extent of bony removal, size of the dural opening, necessity for expansion of the dural space, choice of materials for the duraplasty, and possible need for augmentation with dural sealant are all factors that continue to be debated amongst neurological surgeons worldwide. We herein evaluate the use of fibrin sealant augmentation in combination with locally harvested autologous pericranium for duraplasty in adult CM1 decompression. Methods: Retrospective data collected from January 2006 to December 2011. Data were reviewed for surgical site infection or meningitis, cerebrospinal fluid leak, symptomatic pseudomeningocele, radiographic improvement of hindbrain compression, and postoperative recurrence of symptoms at a minimum of 1 year of follow-up. Outcomes were studied clinically, radiographically, as well as by using a patient-specific questionnaire. Results: Twenty-two consecutive patients were included. One patient required a revision for a delayed graft dehiscence in the setting of a rare form of aseptic meningitis with cerebrospinal fluid (CSF) pleocytosis due to a nonsteroidal anti-inflammatory drug (NSAID) allergy. All remaining patients had successful decompressions with full resolution of their symptoms except for one patient who had persistent headaches. Conclusion: Autologous pericranium with dural sealant augmentation is an effective technique for expansile duraplasty in CM1 decompressions. PMID:23493237

  11. Hemostatic effect of Vivostat patient-derived fibrin sealant on split-thickness skin graft donor sites.

    PubMed

    Drake, David B; Wong, Lesley G

    2003-04-01

    Topical hemostatic agents are used frequently to control bleeding of skin graft donor sites. In this study, the hemostatic properties of Vivostat (Vivolution A/S, Birkerød, Denmark) patient-derived fibrin sealant were compared with a control group of spray thrombin solution, which is considered an industry standard for topical hemostasis. Treatments were applied simultaneously to two randomly chosen halves of a single split-thickness single donor site in patients in five United States surgical centers. The time to achieve satisfactory hemostasis (< or =10 min) was estimated on each half of the wound as the time at which active bleeding had stopped and the wound was suitable for application of a surgical dressing. The time to hemostasis of wounds treated with Vivostat (Vivolution A/S) patient-derived sealant was significantly shorter in comparison with wounds treated with thrombin solution (medians: Vivostat, 31 seconds; thrombin, 58 seconds; p=0.0012). No abnormalities in wound healing were reported for either treatment site 1 week after the operation. Vivostat (Vivolution A/S) sealant is a more rapidly effective topical hemostatic agent than thrombin on split-thickness skin graft donor sites. PMID:12671377

  12. Fibrin Sealant Improves Hemostasis in Peripheral Vascular Surgery: A Randomized Prospective Trial

    PubMed Central

    Schenk, Worthington G.; Burks, Sandra G.; Gagne, Paul J.; Kagan, Steven A.; Lawson, Jeffrey H.; Spotnitz, William D.

    2003-01-01

    Objective To evaluate the efficacy and safety of an investigational fibrin sealant (FS) in a randomized prospective, partially blinded, controlled, multicenter trial. Summary Background Data Upper extremity vascular access surgery using polytetrafluorethylene (PTFE) graft placement for dialysis was chosen as a reproducible, clinically relevant model for evaluating the usefulness of FS. The FS consisted of pooled human fibrinogen (60 mg/mL) and thrombin (500 NIH U/mL). Time to hemostasis was measured, and adverse events were monitored. Methods Consenting adult patients (n = 48) undergoing placement of a standard PTFE graft were randomized in a 2:1:1 ratio to the treatment group using FS (ZLB Bioplasma AG, Bern, Switzerland), oxidized regenerated cellulose (Surgicel, Johnson & Johnson, New Brunswick, NJ), or pressure. Patients received heparin (3,000 IU IVP) before placement of vascular clamps. If the treatment was FS, clamps were left in place for 120 seconds after the application of study material to permit polymerization. If treatment was Surgicel, clamps were left in place until the agent had been applied according to manufacturer’s instructions. If the treatment was pressure, clamps were released as soon as the investigator was ready to apply compression. Immediately after release of the last clamp, the arterial and venous suture lines were evaluated for bleeding. The time to hemostasis at both the venous and arterial sites was recorded. Results Significant (P ≤ .005) reduction in time to hemostasis was achieved in the FS group. Thirteen (54.2%) patients randomized to FS experienced immediate hemostasis at both suture lines following clamp removal compared to no patients using Surgicel or pressure. Only one patient (7.1%) in the Surgicel group and no patients in the pressure group experienced hemostasis at 120 seconds from clamp removal, compared to 13 (54.2%) patients for FS. Adverse events were comparable in all groups. There were no seroconversions

  13. The new heterologous fibrin sealant in combination with low-level laser therapy (LLLT) in the repair of the buccal branch of the facial nerve.

    PubMed

    Buchaim, Daniela Vieira; Rodrigues, Antonio de Castro; Buchaim, Rogerio Leone; Barraviera, Benedito; Junior, Rui Seabra Ferreira; Junior, Geraldo Marco Rosa; Bueno, Cleuber Rodrigo de Souza; Roque, Domingos Donizeti; Dias, Daniel Ventura; Dare, Leticia Rossi; Andreo, Jesus Carlos

    2016-07-01

    This study aimed to evaluate the effects of low-level laser therapy (LLLT) in the repair of the buccal branch of the facial nerve with two surgical techniques: end-to-end epineural suture and coaptation with heterologous fibrin sealant. Forty-two male Wistar rats were randomly divided into five groups: control group (CG) in which the buccal branch of the facial nerve was collected without injury; (2) experimental group with suture (EGS) and experimental group with fibrin (EGF): The buccal branch of the facial nerve was transected on both sides of the face. End-to-end suture was performed on the right side and fibrin sealant on the left side; (3) Experimental group with suture and laser (EGSL) and experimental group with fibrin and laser (EGFL). All animals underwent the same surgical procedures in the EGS and EGF groups, in combination with the application of LLLT (wavelength of 830 nm, 30 mW optical power output of potency, and energy density of 6 J/cm(2)). The animals of the five groups were euthanized at 5 weeks post-surgery and 10 weeks post-surgery. Axonal sprouting was observed in the distal stump of the facial nerve in all experimental groups. The observed morphology was similar to the fibers of the control group, with a predominance of myelinated fibers. In the final period of the experiment, the EGSL presented the closest results to the CG, in all variables measured, except in the axon area. Both surgical techniques analyzed were effective in the treatment of peripheral nerve injuries, where the use of fibrin sealant allowed the manipulation of the nerve stumps without trauma. LLLT exhibited satisfactory results on facial nerve regeneration, being therefore a useful technique to stimulate axonal regeneration process. PMID:27112578

  14. Synaptic plasticity and sensory-motor improvement following fibrin sealant dorsal root reimplantation and mononuclear cell therapy

    PubMed Central

    Benitez, Suzana U.; Barbizan, Roberta; Spejo, Aline B.; Ferreira, Rui S.; Barraviera, Benedito; Góes, Alfredo M.; de Oliveira, Alexandre L. R.

    2014-01-01

    Root lesions may affect both dorsal and ventral roots. However, due to the possibility of generating further inflammation and neuropathic pain, surgical procedures do not prioritize the repair of the afferent component. The loss of such sensorial input directly disturbs the spinal circuits thus affecting the functionality of the injuried limb. The present study evaluated the motor and sensory improvement following dorsal root reimplantation with fibrin sealant (FS) plus bone marrow mononuclear cells (MC) after dorsal rhizotomy. MC were used to enhance the repair process. We also analyzed changes in the glial response and synaptic circuits within the spinal cord. Female Lewis rats (6–8 weeks old) were divided in three groups: rhizotomy (RZ group), rhizotomy repaired with FS (RZ+FS group) and rhizotomy repaired with FS and MC (RZ+FS+MC group). The behavioral tests electronic von-Frey and Walking track test were carried out. For immunohistochemistry we used markers to detect different synapse profiles as well as glial reaction. The behavioral results showed a significant decrease in sensory and motor function after lesion. The reimplantation decreased glial reaction and improved synaptic plasticity of afferent inputs. Cell therapy further enhanced the rewiring process. In addition, both reimplanted groups presented twice as much motor control compared to the non-treated group. In conclusion, the reimplantation with FS and MC is efficient and may be considered an approach to improve sensory-motor recovery following dorsal rhizotomy. PMID:25249946

  15. Fetal membrane patch and biomimetic adhesive coacervates as a sealant for fetoscopic defects.

    PubMed

    Mann, Lovepreet K; Papanna, Ramesha; Moise, Kenneth J; Byrd, Robert H; Popek, Edwina J; Kaur, Sarbjit; Tseng, Scheffer C G; Stewart, Russell J

    2012-07-01

    Iatrogenic preterm premature rupture of membranes after fetoscopic procedures affects 10-47% of patients, secondary to the non-healing nature of membranes and the separation of layers during the entry. In this study we developed an in vitro model to mimic the uterine wall-fetal membrane interface using a water column with one end sealed with human fetal membranes and poultry breast, and a defect was created with an 11 French trocar. Further, a fetal membrane patch in conjunction with multiphase adhesive coacervates modeled after the sandcastle worm bioadhesive was tested for sealing of an iatrogenic defect. The sealant withstood an additional traction of 12 g for 30-60 min and turbulence of the water column without leakage of fluid or slippage. The adhesive is non-toxic when in direct contact with human fetal membranes in an organ culture setting. A fetal membrane patch with multiphase adhesive complex coacervates may help to seal the defect and prevent iatrogenic preterm premature rupture of the membranes. PMID:22373817

  16. Optimizing a spontaneously contracting heart tissue patch with rat neonatal cardiac cells on fibrin gel

    PubMed Central

    Tao, Ze-Wei; Mohamed, Mohamed; Hogan, Matthew; Gutierrez, Laura; Birla, Ravi K.

    2014-01-01

    Engineered cardiac tissues have been constructed with primary or stem cell-derived cardiac cells on natural or synthetic scaffolds. They represent a tremendous potential for treatment of injured areas through addition of tensional support and delivery of sufficient cells. In this study 1 to 6 million (M) neonatal cardiac cells were seeded on fibrin gels to fabricate cardiac tissue patches, and the effects of culture time and cell density on spontaneous contraction rates, twitch forces and paced response frequencies were measured. Electrocardiograms and signal volume index of connexin 43 were also analyzed. Patches of 1–6M cell densities exhibited maximal contraction rates between 305–410 bpm within the first 4 days after plating; low cell densities (1–3M) patches sustained rhythmic contraction longer than high cell densities (4–6M). Patches with 1–6 M cell densities generated contractile forces in the range 2.245–14.065 mN/mm3 on days 4–6. Upon patch formation, a paced response frequency of approximately 6 Hz was obtained, and decreased to approximately 3 Hz after 6 days of culture. High cell density patches contained a thicker real cardiac tissue layer which generated higher R wave amplitudes; however, low density patches had a greater signal volume index of connexin 43. In addition, all patches manifested endothelial cell growth and robust nuclear division. The present study demonstrates that the proper time for in vivo implantation of this cardiac construct is just at patch formation and patches with 3–4M cell densities are the best candidates. PMID:24771636

  17. Mesenchymal stromal cells form vascular tubes when placed in fibrin sealant and accelerate wound healing in vivo.

    PubMed

    Mendez, Julio J; Ghaedi, Mahboobe; Sivarapatna, Amogh; Dimitrievska, Sashka; Shao, Zhen; Osuji, Chinedum O; Steinbacher, Derek M; Leffell, David J; Niklason, Laura E

    2015-02-01

    Non-healing, chronic wounds are a growing public health problem and may stem from insufficient angiogenesis in affected sites. Here, we have developed a fibrin formulation that allows adipose-derived mesenchymal stromal cells (ADSCs) to form tubular structures in vitro. The tubular structures express markers of endothelium, including CD31 and VE-Cadherin, as well as the pericyte marker NG2. The ability for the MSCs to form tubular structures within the fibrin gels was directly dependent on the stoichiometric ratios of thrombin and fibrinogen and the resulting gel concentration, as well as on the presence of bFGF. Fibrin gel formulations that varied in stiffness were tested. ADSCs that are embedded in a stiff fibrin formulation express VE-cadherin and CD31 as shown by PCR, FACS and immunostaining. Confocal imaging analysis demonstrated that tubular structures formed, containing visible lumens, in the stiff fibrin gels in vitro. There was also a difference in the amounts of bFGF secreted by ADSCs grown in the stiffer gels as compared to softer gels. Additionally, hAT-MSCs gave rise to perfusable vessels that were VE-cadherin positive after subcutaneous injection into mice, whereas the softer fibrin formulation containing ADSCs did not. The application of ADSCs delivered in the stiff fibrin gels allowed for the wounds to heal more quickly, as assessed by wound size, amount of granulation tissue and collagen content. Interestingly, following 5 days of healing, the ADSCs remained within the fibrin gel and did not integrate into the granulation tissue of healing wounds in vivo. These data show that ADSCs are able to form tubular structures within fibrin gels, and may also contribute to faster wound healing, as compared with no treatment or to wounds treated with fibrin gels devoid of ADSCs. PMID:25433608

  18. 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

  19. Dental Sealants

    MedlinePlus

    ... Data & Statistics > Find Data by Topic > Dental Sealants Dental Sealants Main Content Dental sealants are thin plastic coatings that protect the chewing surfaces of children’s back teeth from tooth decay. Overall, the prevalence of sealants ...

  20. Dental sealants

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000779.htm Dental sealants To use the sharing features on this ... case a sealant needs to be replaced. How Dental Sealants Are Applied Your dentist applies sealants on ...

  1. 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

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

    PubMed

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

    2015-04-01

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

  3. [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. PMID:23198432

  4. Fibrin Glue as a Drug Delivery System

    PubMed Central

    Spicer, Patrick P.; Mikos, Antonios G.

    2010-01-01

    Fibrin glue has been used surgically for decades for hemostasis as well as a sealant. It has also been researched as both a gel for cell delivery and a vehicle for drug delivery. The drug delivery applications for fibrin glue span tissue engineering to chemotherapy and involve several mechanisms for drug matrix interactions and control of release kinetics. Additionally, drugs or factors can be loaded in the gel via impregnation and tethering to the gel through covalent linkages or affinity based systems. This review highlights recent research of fibrin glue as a drug delivery vehicle. PMID:20637815

  5. Polyphosphate enhances fibrin clot structure

    PubMed Central

    Smith, Stephanie A.

    2008-01-01

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

  6. Cell sealant

    SciTech Connect

    Markin, C.; Book, R.J.; James, D.A.

    1988-04-26

    An electrochemical cell is described comprising an anode, a cathode and an electrolyte disposed within an open ended cylindrical metallic cell container, with an insulative cell top member being positioned within the open end of a sealant at the interface between the cell top member and the metallic cell container. The sealant is a mixture of a Type 2 BUR asphalt and an elastomeric material selected from the group consisting of (cis-1,4-polyisoprene), styrene-butadiene copolymer (SBR), cis-1,4-polybutadiene and styrene butadiene styrene (SBS), styrene isoprene styrene (SIS), neoprene (poly-chloprene), acrylonitrile-butadiene copolymer (NBR), ethylene-propylene elastomers (EPR), butyl rubber (copolymers of isobutylene), urethane, nitrile (polymers of butadiene and acrylonitrile), polysulfide, polyacrylate, silicone, chlorosulfonated polyethylene, and EPDM (terpolymers of ethylene, propylene and diene monomers), and mixtures thereof, and wherein the elastomeric material is substantially inert to the electrolyte and is present in an amount between 0.5% to 10% by weight of the asphalt.

  7. Epicardial Tachosil Patch Repair of Ventricular Rupture in a 90-Year-Old After Mitral Valve Replacement.

    PubMed

    Feng, William; Coady, Michael

    2016-06-01

    We report our experience with emergent treatment of ventricular rupture following a mitral valve replacement in a 90 year-old male. The repair was performed using a Tachosil patch (Baxter Health Care Corporation, Westlake Village, California), a fibrin sealant coated on an equine collagen sponge, and BioGlue (Cryolife, Kenneson, GA) and bovine pericardium (Edwards Lifesciences, Irvine, CA). Aside from early ventricular dysfunction requiring a low-dose dopamine infusion, this patient's recovery was uneventful. Follow-up echocardiograms demonstrated no gross anatomic abnormality at the repair site, and steady improvement in his ventricular function. PMID:27211944

  8. Biochemical, mechanical, and morphological properties of a completely autologous platelet-rich wound sealant.

    PubMed

    Wu, Xiuwen; Ren, Jianan; Luan, Jianfeng; Yao, Gengong; Li, Jieshou

    2012-06-01

    The optimal composition of fibrin sealant preparations is not known. We, therefore, sought to construct a series of sealants from autologous components and compare their functioning to Bioseal a commonly used sealant. Characteristics of the platelet-rich plasma, cryoprecipitate, and thrombin were determined and compared to commercial glue from composition, function, and microscopy aspects. The concentrations of platelets as well as fibronectin in autologous fibrin glues were significantly higher than those in commercial ones (P < 0.001). Mechanical values (maximum amplitude and clot strength) obtained from thrombelastograph assays in two groups were not significantly different (P > 0.05). A dense platelet surface and fibrin net structures could be observed in the autologous samples, whereas there were only sparse fibrin nets without cellular components in Bioseal. Characterization of autologous and Bioseal fibrin sealants and their performance do not have significant difference in biochemical and mechanical properties. The entirely autologous platelet-rich gel in the present study may get wide application in future practice after confirmation of its safety, efficiency, and economic benefits. PMID:22395185

  9. Adhesive and sealant interfaces for general surgery applications.

    PubMed

    Scognamiglio, Francesca; Travan, Andrea; Rustighi, Isabella; Tarchi, Paola; Palmisano, Silvia; Marsich, Eleonora; Borgogna, Massimiliano; Donati, Ivan; de Manzini, Nicolò; Paoletti, Sergio

    2016-04-01

    The main functions of biological adhesives and sealants are to repair injured tissues, reinforce surgical wounds, or even replace common suturing techniques. In general surgery, adhesives must match several requirements taking into account clinical needs, biological effects, and material features; these requirements can be fulfilled by specific polymers. Natural or synthetic polymeric materials can be employed to generate three-dimensional networks that physically or chemically bind to the target tissues and act as hemostats, sealants, or adhesives. Among them, fibrin, gelatin, dextran, chitosan, cyanoacrylates, polyethylene glycol, and polyurethanes are the most important components of these interfaces; various aspects regarding their adhesion mechanisms, mechanical performance, and resistance to body fluids should be taken into account to choose the most suitable formulation for the target application. This review aims to describe the main adhesives and sealant materials for general surgery applications developed in the past decades and to highlight the most important aspects for the development of future formulations. PMID:25891348

  10. PRESSURE ACTIVATED SEALANT TECHNOLOGY

    SciTech Connect

    Michael A. Romano

    2004-04-01

    The objective of this project is to develop new, efficient, cost effective methods of internally sealing natural gas pipeline leaks through the application of differential pressure activated sealants. In researching the current state of the art for gas pipeline sealing technologies we concluded that if the project was successful, it appeared that pressure activated sealant technology would provide a cost effective alternative to existing pipeline repair technology. From our analysis of current field data for a 13 year period from 1985 to 1997 we were able to identify 205 leaks that were candidates for pressure activated sealant technology, affirming that pressure activated sealant technology is a viable option to traditional external leak repairs. The data collected included types of defects, areas of defects, pipe sizes and materials, incident and operating pressures, ability of pipeline to be pigged and corrosion states. This data, and subsequent analysis, was utilized as a basis for constructing applicable sealant test modeling.

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

    PubMed

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

    2014-08-01

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

  12. 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

  13. Treatment of gingival recession using free gingival graft with fibrin fibronectin sealing system: A novel approach.

    PubMed

    Srinivas, B V V; Rupa, N; Halini Kumari, K V; Rajender, A; Reddy, M Narendra

    2015-08-01

    Periodontal plastic surgery is the branch of periodontology that is focused mainly on the correction or elimination of mucogingival problems associated with lack of attached gingiva, a shallow vestibule and aberrant frenum. Various mucogingival surgical procedures are used to halt the progression of the gingival recession and to correct poor esthetic appearance. Free gingival autograft is one of the most common techniques used for a gingival recession in areas of inadequate attached gingiva in the mandibular anterior region. Fibrin sealants are human plasma derivatives that mimic the final stages of blood coagulation, forming a fibrin clot. Fibrin Sealants enhances the overall outcome of surgical intervention because of their hemostatic, adhesive, and healing properties. These properties of fibrin sealants may reduce operating time, prevent complications, and enhance the overall outcome of many surgical interventions. Hence, this case report aims to investigate the clinical effectiveness of free gingival graft along with the commercially available fibrin-fibronectin sealing system (Tissucol(®)) in the treatment of Miller's class II gingival recession. PMID:26538956

  14. 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.

  15. 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…

  16. What Is the Biological and Clinical Relevance of Fibrin?

    PubMed

    Litvinov, Rustem I; Weisel, John W

    2016-06-01

    As our knowledge of the structure and functions of fibrinogen and fibrin has increased tremendously, several key findings have given some people a superficial impression that the biological and clinical significance of these clotting proteins may be less than earlier thought. Most strikingly, studies of fibrinogen knockout mice demonstrated that many of these mice survive to weaning and beyond, suggesting that fibrin(ogen) may not be entirely necessary. Humans with afibrinogenemia also survive. Furthermore, in recent years, the major emphasis in the treatment of arterial thrombosis has been on inhibition of platelets, rather than fibrin. In contrast to the initially apparent conclusions from these results, it has become increasingly clear that fibrin is essential for hemostasis; is a key factor in thrombosis; and plays an important biological role in infection, inflammation, immunology, and wound healing. In addition, fibrinogen replacement therapy has become a preferred, major treatment for severe bleeding in trauma and surgery. Finally, fibrin is a unique biomaterial and is used as a sealant or glue, a matrix for cells, a scaffold for tissue engineering, and a carrier and/or a vector for targeted drug delivery. PMID:27056152

  17. Effect of alkyl chain length on the interfacial strength of surgical sealants composed of hydrophobically-modified Alaska-pollock-derived gelatins and poly(ethylene)glycol-based four-armed crosslinker.

    PubMed

    Mizuta, Ryo; Ito, Temmei; Taguchi, Tetsushi

    2016-10-01

    Surgical sealants are widely used clinically. Fibrin sealant is a commonly used sealant, but is ineffective under wet conditions during surgery. In this study, we developed surgical sealants composed of hydrophobically modified Alaska-pollock-derived gelatins (hm-ApGltns) with different alkyl chain lengths from C3 to C18 and a poly(ethylene)glycol-based 4-armed crosslinker (4S-PEG). The burst strength of the hm-ApGltns-based sealant was evaluated using a fresh porcine blood vessel and was found to increase with increasing alkyl chain length from 167±22 to 299±43mmHg when the substitution ratio of amino groups of ApGltn was around 10mol%. The maximum burst strength was observed when stearoyl-group modified ApGltn (Ste-ApGltn)/4S-PEG-based sealant was used, displaying 3-fold higher burst strength than the original ApGltn (Org-ApGltn)/4S-PEG sealant, and 10-fold higher than the commercial fibrin sealant. Ste-ApGltn/4S-PEG-based sealant was biodegraded in rat subcutaneous tissue within 8 weeks without severe inflammation. By molecular interaction analysis using surface plasmon resonance, the binding constant of Ste-ApGltn to fibronectin was found to be 9-fold higher than that of Org-ApGltn. Therefore, the developed sealant, in particular the Ste-ApGltn/4S-PEG-based sealant, has potential applications in the field of cardiovascular surgery as well as thoracic surgery. PMID:27341135

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

    PubMed

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

    2015-01-01

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

  19. 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.

  20. Fluoride release from fissure sealants.

    PubMed

    Garcia-Godoy, F; Abarzua, I; De Goes, M F; Chan, D C

    1997-01-01

    This 30-day study, compared the amounts and patterns of fluoride release from 5 commercially available fluoride-containing pit and fissure sealants: FluroShield, Helioseal-F, Ultraseal XT, Baritone L3, and Teethmate-F; Delton without fluoride, was used as control. Disc-shaped samples of each sealant were immersed in distilled water and the fluoride release was measured periodically until day 30. All the fluoridated sealants tested released measurable fluoride throughout the test period in a similar pattern: the greatest amount of fluoride was released in the first 24 hours after mixing, fell sharply on the second day and decreased slowly for the last days. On day one, Baritone L3 released significantly more fluoride than all other materials. Teethmate-F released the highest amount of fluoride during all the other time intervals from day 2, until day 30. PMID:9643204

  1. Human Adipose Stromal Vascular Cell Delivery in a Fibrin Spray

    PubMed Central

    Zimmerlin, Ludovic; Rubin, J. Peter; Pfeifer, Melanie E.; Moore, L.R.; Donnenberg, Vera S.; Donnenberg, Albert D.

    2014-01-01

    Background Adipose tissue represents a practical source of autologous mesenchymal stromal cells (MSC) and vascular-endothelial progenitor cells, available for regenerative therapy without in vitro expansion. One of the problems confronting the therapeutic application of such cells is how to immobilize them at the wound site. Here, we evaluated in vitro the growth and differentiation of human adipose stromal vascular fraction (SVF) cells after delivery using a fibrin spray system. Methods SVF cells were harvested from four human adult patients undergoing elective abdominoplasty using the LipiVage™ system. After collagenase digestion, mesenchymal and endothelial progenitor cells (pericytes, supra-adventitial stromal cells, endothelial progenitors) were quantified by flow cytometry before culture. SVF cells were applied to culture vessels using the Tisseel™ fibrin spray system. SVF cell growth and differentiation was documented by immunofluorescence staining and photomicrography. Results SVF cells remained viable following application and were expanded up to three weeks, when they reached confluence and adipogenic differentiation. Under angiogenic conditions, SVF cells formed endothelial (vWF+, CD31+ and CD34+) tubules surrounded by CD146+ and α-SMA+ perivascular/stromal cells. Discussion Human adipose tissue is a rich source of autologous stem cells, which are readily available for regenerative applications such as wound healing, without in vitro expansion. Our results indicate that mesenchymal and endothelial progenitor cells, prepared in a closed system from unpassaged lipoaspirate samples, retain their growth and differentiation capacity when applied and immobilized on a substrate using a clinically approved fibrin sealant spray system. PMID:23260090

  2. Fibrin glue in ophthalmology

    PubMed Central

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

    2009-01-01

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

  3. 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

  4. Salmon Patch

    MedlinePlus

    ... the head. Salmon patches are different from port-wine stains (discussed as a separate topic) in that ... difference between a salmon patch and a port-wine stain. In the past, port-wine stains and ...

  5. 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

  6. 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.

  7. Platelet Rich Fibrin Matrix Improves Wound Angiogenesis via Inducing Endothelial Cell Proliferation

    PubMed Central

    Roy, Sashwati; Driggs, Jason; Elgharably, Haytham; Biswas, Sabyasachi; Findley, Muna; Khanna, Savita; Gnyawali, Urmila; Bergdall, Valerie K.; Sen, Chandan K.

    2013-01-01

    The economic, social and public health burden of chronic ulcers and other compromised wounds are 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 VEGF released from PRFM was primarily responsible for endothelial mitogenic response via ERK 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. PMID:22092846

  8. Effects of sealant, viscosity, and bonding agents on microleakage of fissure sealants: An in vitro study

    PubMed Central

    Mehrabkhani, Maryam; Mazhari, Fatemeh; Sadeghi, Samaneh; Ebrahimi, Masoumeh

    2015-01-01

    Objective: The aim of this study was to evaluate the effects of enamel or dentin bonding agent (DBA) and sealant viscosity on sealant microleakage. Materials and Methods: Sixty extracted human premolars were randomly divided into two equal groups (based on sealant viscosity) and each group was divided into three subgroups of 10 teeth. Group 1 (low viscosity sealant, Seal-Rite, Pulpdent, USA with 7.7% filler): Prophylaxis, enameloplasty, etching of occlusal surfaces with 38% of phosphoric acid gel, rinsing and drying, followed by (1) enamel bonding agent (EBA) (Margin Bond, Coltène/Whaledent AG) or (2) DBA (Excite, Ivoclar Vivadent AG, Liechtenstein) or (3) no bonding (NB) prior to sealant application. In Group 2, similar procedures were performed except for applying a high viscosity sealant (Seal-Rite, Pulpdent, The USA with 34.4% filler). Specimens were thermocycled and then immersed in a 0.5% basic fuchsine solution for 24 h next, buccolingual slices of samples were scored under a stereomicroscope. The Kruskal–Wallis and Mann–Whitney U-tests were used for data analysis. Results: There was no significant difference between DBA, EBA, and NB subgroups in the microleakage scores in both groups. Low viscosity sealant had a lower microleakage than the high viscosity sealant in both DBA (P = 0.002) and NB (P = 0.041) subgroups. Conclusion: The results indicated that the use of low viscosity sealant reduced the microleakage of pit and fissure sealants. However, the use of a bonding agent before sealant placement didn’t affect the microleakage. PMID:26929696

  9. Sealant provides economical solution to subsurface leaks

    SciTech Connect

    Silverman, S.

    1999-02-01

    A series of unique field-tested leak sealants have been developed that can withstand the extreme pressure and temperature conditions found in the oilfield. The unique quality of the sealants is that the sealing mechanism is activated by the differential pressure created through a leak site. The sealants are comparable with oil- and glycol-based hydraulic fluids and are particularly useful for sealing leaks in subsurface safety valves, wellhead tubing and casing hanger seals, PBR seal joints, umbilical leaks and subsea well control systems. The chemical remains fluid until it is released through a leak site. The sealant mimics platelets in the human body by forming deposits on leak walls. This process creates a matrix across the leak similar to coagulating blood on a cut. Leak sites can be metal-to-metal seals, elastomer seals, pinhole leaks, or connection leaks. The pressure-activated sealant is stable at high pressures and temperatures up to 15,000 psi and 320 F and does not react with elastomers. The sealant will not plug valves because any pressure from that occurs while opening and closing the valve only lasts for a few seconds, and it is a sustained pressure drop that is required to activate the chemical.

  10. 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

  11. Evaluation of various generic types of building sealants against ASTM C-920, standard specification for elastomeric joint sealants

    SciTech Connect

    Fiorillo, A.R.

    1996-12-31

    A number of sealant manufacturers suggest that although they supply primers for their sealants, in many cases the primers may not be necessary. They usually suggest running a test on the substrates the sealants are to be used with to determine if the primers are needed. This paper will discuss the results of testing several commercially available polysulfide, silicone and polyurethane sealants against ASTM C-920, Standard Specification for Elastomeric Joint Sealants. Morar, plate glass and anodized aluminum were used as the substrates. Where manufacturers supplied primers, the sealant was tested with and without their primer. Where the manufacturer did not recommend primers, testing was only doe without a primer.

  12. Pit and fissure sealant: review of the literature.

    PubMed

    Simonsen, Richard J

    2002-01-01

    For this literature review of pit and fissure sealant, 1,465 references were selected by a search for "sealants" on PubMed. References were limited to dental journals and papers in the English language. The search comprised papers from 1971 to October 2001. Additional papers of historical significance prior to 1971 were added from memory and from reference lists published in early papers. This paper reviewed the literature on pit and fissure sealants under the following subheadings: (1) laboratory studies, (2) clinical technique and tooth preparation, (3) etching time, (4) auxiliary application of pit and fissure sealant, (5) retention and caries prevention, (6) fluoride used with sealants and fluoride-containing sealant, (7) glass ionomer materials as sealants, (8) options in sealant: filled vs unfilled; colored vs clear; autocure vs light-initiated, (9) sealant placed over caries in a therapeutic manner, (10) cost effectiveness of sealant application, (11) underuse of pit and fissure sealant, (12) the estrogenicity issue, (13) use of an intermediate bonding layer to improve retention, (14) new developments and projections, and (15) summary and conclusions. From a careful and thorough review of peer-reviewed publications on pit and fissure sealant, it is clear that sealants are safe, effective and underused (at least underused in the United States). Pit and fissure sealant is best applied to high-risk populations by trained auxiliaries using sealant that incorporates the benefit of an intermediate bonding layer, applied under the rubber dam or with some alternative short-term, but effective, isolation technique, onto an enamel surface that has been cleaned with an air polishing technique and etched with 35% phosphoric acid for 15 seconds. The dental profession awaits with enthusiasm, and some impatience, the incorporation of dentin-bonding technology into the development of a modern, more durable, resin-based sealant. PMID:12412954

  13. [Fibrin glue and bone regeneration].

    PubMed

    Zilch, H; Wolff, R

    1987-01-01

    The osteoinductive property of fibrin glue with and without admixture of aprotinin was proven in animal model. Aprotinin as an inhibitor of the fibrinolysis is supposed to be an inhibitor of the osteogenesis, too. Three holes of 4 mm diameter and 2 mm depth were placed into the diaphysis of both femura in 12 adults dogs. The defects were filled with either pure fibrin glue or with glue containing aprotinin (3000 KIE), or with nothing (vacant). After 8 weeks the quantity of the new built woven-bone was examined by plane geometry and the "Bone Metabolising Unit (BMU)" (Frost) which are crossing the border of lamellar bone and new woven bone were counted out. There was seen no statistical significantly between the three groups neither in the quantity of new bone nor in the BMU. Therefore the fibrin glue has no osteoinductive property. PMID:2441537

  14. Bonded amalgam sealants and adhesive resin sealants: five-year clinical results.

    PubMed

    Staninec, Michal; Artiga, Nelson; Gansky, Stuart A; Marshall, Grayson W; Eakle, Stephan

    2004-05-01

    Bonded amalgams were used as pit-and-fissure sealants without mechanical preparation. They were compared with resin-based pit-and-fissure sealants for retention over a 5-year period. Clinical examinations at 6 months, 1 year, 2 years, and 5 years revealed no difference between the two techniques. Although amalgam sealants may not be practical by themselves, they can be used to seal pits and fissures surrounding very conservative preparations, in the "preventive amalgam restoration." Conventional amalgam retentive features and 90-degree cavosurface margins may not be necessary when bonding is used with amalgam. PMID:15130073

  15. Development of new photopolymerizable dental sealants.

    PubMed

    Davidenko, N; Cohen, M E; Diaz, J M; Sastre, R

    1998-01-01

    This paper describes the results obtained in the optimization of the composition of dental sealants in relation to the nature and proportions of monomer mixtures and photoinitiating system employed. The quantification and variation of certain parameters which determine the quality of a dental sealant (such as viscosity and penetrating power, residual double bonds, solubility and absorption, volume shrinkage and certain specific mechanical properties) have resulted in the development of new formulations. The composition which has achieved the best results of all the above properties was that corresponding to the monomer mixture bis-GMA/tri(ethylene glycol) dimethacrylate (TEGDMA) 40/60 wt%, and the photoinitiating system camphorquinone (CQ) with co-initiators N,N,3,5-tetramethyaniline (TMA) or N,N-dimethyl-p-toluidine (DMPT) in the ratio 1:1. The final properties and characteristics of the obtained formulations are superior to those of commercial dental sealants currently in use. PMID:9747983

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Organo-Selenium-containing Dental Sealant Inhibits Bacterial Biofilm

    PubMed Central

    Tran, P.; Hamood, A.; Mosley, T.; Gray, T.; Jarvis, C.; Webster, D.; Amaechi, B.; Enos, T.; Reid, T.

    2013-01-01

    Oral bacteria, including Streptococcus mutans and Streptococcus salivarius, contribute to tooth decay and plaque formation; therefore, it is essential to develop strategies to prevent dental caries and plaque formation. We recently showed that organo-selenium compounds covalently attached to different biomaterials inhibited bacterial biofilms. Our current study investigates the efficacy of an organo-selenium dental sealant (SeLECT-DefenseTM sealant) in inhibiting S. mutans and S. salivarius biofilm formation in vitro. The organo-selenium was synthesized and covalently attached to dental sealant material via standard polymer chemistry. By colony-forming unit (CFU) assay and confocal microscopy, SeLECT-DefenseTM sealant was found to completely inhibit the development of S. mutans and S. salivarius biofilms. To assess the durability of the anti-biofilm effect, we soaked the SeLECT-DefenseTM sealant in PBS for 2 mos at 37°C and found that the biofilm-inhibitory effect was not diminished after soaking. To determine if organo-selenium inhibits bacterial growth under the sealant, we placed SeLECT-Defense sealant over a lawn of S. mutans. In contrast to a control sealant, SeLECT-DefenseTM sealant completely inhibited the growth of S. mutans. These results suggest that the inhibitory effect of SeLECT-DefenseTM sealant against S. mutans and S. salivarius biofilms is very effective and durable. PMID:23475900

  4. 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

  5. Bonded amalgam sealants: two-year clinical results.

    PubMed

    Staninec, M; Eakle, W S; Silverstein, S; Marshall, G W; Artiga, N

    1998-03-01

    The authors used bonded amalgams as pit and fissure sealants without mechanical preparation. They compared the two-year retention of the bonded amalgams with that of resin-based pit and fissure sealants. Clinical examinations at six months, one year and two years revealed no difference between the retention of the two sealants. This technique opens up the possibility of using bonded amalgam in pits and fissures surrounding very conservative preparations in a preventive amalgam restoration. PMID:9529807

  6. Moisture-tolerant resin-based sealant: A boon

    PubMed Central

    Bhat, Prasanna Kumar; Konde, Sapna; Raj, Sunil N.; Kumar, Narayan Chandra

    2013-01-01

    Background and Objectives: Pit and fissure sealants are highly effective in preventing occlusal caries. The present study clinically evaluated and compared the retention and development of caries when sealed with moisture-tolerant resin-based sealant, conventional resin-based sealant with and without a bonding agent, and Glass Ionomer Cement Sealant in young permanent teeth. Materials and Methods: A total of 80 healthy cooperative children aged 6-9 years who were at high caries risk with all four newly erupted permanent first molars were included in the study. Teeth were divided into 4 groups using a full-factorial design, and each of the molars was sealed with the four different sealant material. Evaluation of sealant retention and development of caries was performed at 6 and 12 months using Modified Simonsen's criteria. The data obtained were tabulated and subjected to statistical analysis using Kruskal-Wallis Test and Mann-Whitney Test. Result and Conclusion: The result from the present study indicated that moisture-tolerant resin-based sealant could be successfully used as a pit and fissure sealant because its hydrophilic chemistry makes it less technique sensitive and simplifies the sealant application procedure. PMID:24124301

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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. PMID:23723146

  12. 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 ...

  13. Methylphenidate Transdermal Patch

    MedlinePlus

    ... still remove the patch at your regular patch removal time. Do not apply extra patches to make ... room temperature and away from excess heat and moisture (not in the bathroom). Do not refrigerate or ...

  14. Rivastigmine Transdermal Patch

    MedlinePlus

    ... still remove the patch at your regular patch removal time. If it is almost time for the ... room temperature and away from excess heat and moisture (not in the bathroom). Throw away any patches ...

  15. 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 criteria); (3) "Education and…

  16. Effect of Heat Treatment on Properties of Glass Nanocomposite Sealants.

    PubMed

    Lee, Dong Bok; Ha, Su-Jeong; Jang, Dong-Hoon; Park, Sung; Bae, Joongmyeon; Lee, Jae Chun

    2015-01-01

    The objective of this study was to investigate the effect of heat treatments on the viscosities and electrical conductivities of glass sealants to be used in solid oxide fuel cells. Glass-based sealants, both with and without an alumina nanopowder added as a nanofiller, were heat treated at temperatures ranging from 750 degrees C to 770 degrees C for periods of up to 240 h. The effects of heat treatments on the viscosities, electrical conductivities and phase transformations of the sealants were investigated. The results showed that alumina nanopowder added to the glass increased both high-temperature electrical conductivities and the viscosities of the sintered glass nanocomposite sealants. However, lengthy heat treatments decreased the electrical conductivities of the glass nanocomposite sealants. This decrease in the conductivities of the heat-treated glass nanocomposites was attributed to the crystallization of glass phase, owing to the dissolution of the alumina nanofiller in the sealing glass. PMID:26328386

  17. 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).

  18. Viscoseal performance with rarefied-gas sealant

    NASA Technical Reports Server (NTRS)

    Milligan, M. W.

    1971-01-01

    A fundamental study of viscoseals having a rarefied gas as the sealant has been conducted. Both experimental and analytical investigations are reported. Three different analytical models have been formulated and are described in detail. An experimental investigation has been 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.

  19. 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.

  20. 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.

  1. Granisetron Transdermal Patch

    MedlinePlus

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

  2. 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.

  3. Selection and use of seals and sealants at building roofs

    SciTech Connect

    Johnson, P.G.

    1998-12-31

    In general, the roofing industry has performed reasonably well in providing seals and sealants which are adequate for various roof membranes or other roofing systems. However, the seal and sealant conditions created by exposures, and the interfaces of various systems, components, and materials, is not generally well understood. This may result in a design, and its subsequent construction, which is subject to leakage, damage, premature deterioration, and disruption to building occupancy. To date, the roofing industry has not addressed this issue of seals and sealants at a detail level. This paper addresses the primary considerations for selecting and installing building seals and sealants at low slope roofs, and provides a methodology and a checklist to be used in the selection, detailing and application of these roofing seals and sealants. The three basic types of seal conditions normally found at building roofs, and the basic causes of construction problems and criteria for evaluating roof seals and sealants are identified. The drawing examples, methodology, and checklists provide information to assist designers and others in avoiding problematic conditions associated with seals and sealants, in both new and remedial roof design and construction. This paper addresses technical as well as non-technical issues such as compatibilities, movement capabilities, ultra violet resistance, quality assurance, and workmanship and maintenance. Steep roof systems such as asphaltic shingles, clay tile, slate, and sheet metal are excluded from consideration in this paper.

  4. 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.

  5. Sealants and xylitol chewing gum are equal in caries prevention.

    PubMed

    Alanen, P; Holsti, M L; Pienihäkkinen, K

    2000-12-01

    Sealants and xylitol have been demonstrated to prevent dental decay, but their effect has never been compared in the same study. Regular use of xylitol chewing gum during 2 or 3 school years was compared with application of occlusal sealants in a randomized study. The reliability of the clinical observations was controlled by examining the presence of dental decay in the same teeth from bitewing radiographs in a blind study. After 5 years, no statistically significant differences between the sealant and xylitol groups were found. The results were in line with the results from separate studies with sealants or xylitol. There were no great differences between the costs of the measures. The selection between the compared preventive measures has to be made on the basis of practical aspects such as caries occurrence, availability of personnel and other resources, opportunity costs, cooperation with schools, and other local conditions. PMID:11196404

  6. 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.

  7. Fluoride release and uptake abilities of different fissure sealants

    PubMed Central

    Andenna, Gianluigi; Ceci, Matteo; Beltrami, Riccardo; Colombo, Marco; Cucca, Lucia

    2016-01-01

    Background The long-term capability of resin sealants and glass ionomer cements to release fluoride is associated to a reduction in pit and fissure caries. The regular use of fluoride varnishes/toothpastes can result in the absorption of fluoride into the sealant. The objective of the present study was to assess the fluoride release/uptake capacities of different fissure sealants. Material and Methods Three different fissure sealants (Fuji Triage/GC, Fissurit FX/Voco and Grandio Seal/Voco) were examined. Ten discs of each material were prepared. Each disc was incubated with distilled water and then the solution analyzed for diluted for fluoride concentration, using a combination of fluoride electrode (OrionGP 1 S/N 13824, Orion Research Inc, Boston, MA, USA) connected to an expandable ion analyzer (Orion 720A, Orion Research Inc, Boston, MA, USA). Standard curves between 1 and 100 ppm F- were used to calibrate the electrode. Cumulative fluoride release was measured on days 1, 2, 3, 5, 7, 21, 35 and 49, then two different fluoride varnishes/pastes (Profluorid Varnish/Voco, MI Paste Plus/GC), were applied to the sealants tested, and fluoride release (after reuptake) was measured on days 56, 70 and 84. Results Kruskal Wallis test confirmed significant differences in fluoride release between Fuji Triage/GC and Fissurit FX/Voco and Grandio Seal/Voco from day 1 (P < 0.001). The application of fluoride varnish Profluorid Varnish enhanced the fluoride release for all sealants (P < 0.05). MI Paste Plus enhanced the fluoride release for all sealants except for Fuji Triage/GC (P > 0.05). Conclusions The GIC-based sealant (Fuji Triage/GC) released significantly more fluoride than the resin sealants tested. The exposure to the fluoridated varnish (Profluorid Varnish) significantly recharged the sealants tested more than the CPP-ACPF toothpaste (MI Paste Plus). Key words:Fissure sealants, fluoride release, fluoride uptake, glass ionomer cements. PMID:27398179

  8. Anaerobic polymers as high vacuum leak sealants

    NASA Technical Reports Server (NTRS)

    Kendall, B. R. F.

    1982-01-01

    Anaerobic polymers are useful as solventless leak sealants with good vacuum properties at moderate temperatures. Loctite 290 can seal leaks in a range generally encountered in carefully constructed ultrahigh vacuum and high vacuum systems. It was found that small leaks are sealed best under vacuum, whereas large leaks should be sealed at atmospheric pressure. The high-temperature behavior of Loctite 290 is limited by its fast cure, which prevents deep penetration into small leaks; cracking eventually occurs at the entrance to the leak. Repeated thermal cycling to about 300 C is possible, however, provided viscosity, curing time, and leak size are properly matched to ensure penetration into the body of the leak. This may require special formulations for high temperature vacuum applications.

  9. Fissure sealants: Knowledge and practice of Yemeni dental practitioners

    PubMed Central

    Al-Maweri, Sadeq Ali; Al-Jamaei, Aisha Ahmed; Halboub, Esam Saleh; Al-Soneidar, Walid Ahmed; Tarakji, Bassel; Alsalhani, Anas

    2016-01-01

    Objectives This study was conducted to evaluate Yemeni dental practitioners' knowledge and practices concerning fissure sealants. Materials and Methods: A modified questionnaire consisted of 25-items was distributed to 500 dentists working in Sana'a City. Descriptive statistics and Chi-square/Fisher's exact tests were used for statistical analyses. Results: The response rate was 74%. Most of the respondents were male (61.3%), general practitioners (84.2%), and had <5 years of clinical experience (48.3%). The respondents showed a reasonable level of knowledge about sealants, with the majority (88%) believed that there is strong scientific evidence about fissure sealants effectiveness and around 90% showed a good understanding of sealant placement instructions. On the other hand, respondents showed insufficient knowledge about sealants clinical practice. Conclusion: Although a high proportion of dental practitioners showed adequate knowledge about dental sealant, following guidelines and standardized procedures in clinical practice is lacking. These emphasize the need for regular continuing education courses for dental professional. PMID:27095903

  10. 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 ...

  11. Lidocaine Transdermal Patch

    MedlinePlus

    ... that area. Use scissors to remove the outer seal from the package. Then pull apart the zipper seal. Remove up to three patches from the package and press the zipper seal tightly together. The remaining patches may dry out ...

  12. 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.

  13. 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.

  14. Fibrin Architecture in Clots: A Quantitative Polarized Light Microscopy Analysis

    PubMed Central

    Whittaker, Peter; Przyklenk, Karin

    2009-01-01

    Fibrin plays a vital structural role in thrombus integrity. Thus, the ability to assess fibrin architecture has potential to provide insight into thrombosis and thrombolysis. Fibrin has an anisotropic molecular structure, which enables it to be seen with polarized light. Therefore, we aimed to determine if automated polarized light microscopy methods of quantifying two structural parameters; fibrin fiber bundle orientation and fibrin's optical retardation (OR: a measure of molecular anisotropy) could be used to assess thrombi. To compare fibrin fiber bundle orientation we analyzed picrosirius red-stained sections obtained from clots formed: (A) in vitro, (B) in injured and stenotic coronary arteries, and (C) in surgically created aortic aneurysms (n = 6 for each group). To assess potential changes in OR, we examined fibrin in picrosirius red-stained clots formed after ischemic preconditioning (10 minutes ischemia + 10 minutes reflow; a circumstance shown to enhance lysability) and in control clots (n = 8 each group). The degree of fibrin organization differed significantly according to the location of clot formation; fibrin was most aligned in the aneurysms and least aligned in vitro whereas fibrin in the coronary clots had an intermediate organization. The OR of fibrin in the clots formed after ischemic preconditioning was lower than that in controls (2.9 ± 0.5 nm versus 5.4 ± 1.0 nm, P < 0.05). The automated polarized light analysis methods not only enabled fibrin architecture to be assessed, but also revealed structural differences in clots formed under different circumstances. PMID:19054699

  15. 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%.

  16. One year clinical evaluation of the retention and quality of two fluoride releasing sealants.

    PubMed

    Ganss, C; Klimek, J; Gleim, A

    1999-12-01

    In this prospective, double-blind, split-mouth-designed study, sealant retention rate and quality of two light-cured, fluoride-releasing sealants (Helioseal F, Fissurit F) were compared. Additionally the influence of the isolation method was evaluated. Fifty-eight subjects participated; 1 year later 54 of these (mean age 13.7 +/- 3.6 years) were reexamined. Sealants were applied to 203 tooth pairs (168 conventional and 25 invasive sealants). After 1 year, 193 tooth pairs were available for study; 82 were applied using rubber dam and 111 using cotton roll isolation. Retention rate and sealant quality were judged clinically and with photographs. The initial sealant quality was comparable for both materials. After 1 year, 53.4% of the Helioseal F sealants (44.6% of the Fissurit F sealants) were fully intact, 43.1% (51.8%) partially intact and 3.6% (3.6%) completely lost (P < 0.001). Placement under rubber dam resulted in significantly higher retention rates for both sealants (P < 0.001) as well as in an improved sealant quality. Cases of complete loss only occurred in teeth isolated with cotton rolls. The findings suggest that placement under rubber dam increases retention rate and sealant quality and may reduce material dependent factors that are considered a cause of sealant failures. PMID:10803133

  17. 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

  18. Dry-cured ham restructured with fibrin.

    PubMed

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

    2014-09-15

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

  19. Platelets and fibrin strands during clot retraction.

    PubMed

    Morgenstern, E; Korell, U; Richter, J

    1984-03-15

    The ultrastructure of platelet fibrin contacts (PFC) and the course of the strands was investigated in serial sections of retracted clots with the help of specimen tilting. We found after retraction in a test tube as well as under isometric conditions in the resonance thrombograph, after HARTERT, an uniform type of PFC. The side to side contact between platelet surface and fibrin strands displayed a 15 nm wide space which was bridged of 10 - 30 nm by filamentary structure. In each case the direction of the fibrin strands changed on contact with the platelet surface (bend). These bends recurred if the adhering strands ran over a longer distance on the platelet surface. The bends can be explained by non-directional movement of the platelets or of their pseudopodia. Microfilaments (actomyosin) which run straight in pseudopodia and often also twisted in the platelet body support this assumption. The described mechanism - contact of the thrombin activated platelets with fibrin strands and simultaneous nondirectional movement of the platelets which bind further sections of the adhering strands to their surface - would provide a more satisfactory explanation for the retraction of the clot to 1/10 of its original volume. PMID:6539004

  20. Glass ionomer ART sealant and fluoride-releasing resin sealant in fissure caries prevention – results from a randomized clinical trial

    PubMed Central

    2014-01-01

    Background The relative performance of ART sealant and fluoride-releasing resin sealant in preventing fissure caries in permanent molars was compared in a randomized clinical trial conducted in southern China (ClinicalTrials.gov NCT01829334). Methods After obtaining ethical approval, healthy schoolchildren who had permanent first molars with occlusal fissures which were sound but deep or presented with only incipient caries were recruited for the study. Included molars were randomly allocated into one of four parallel study groups in units of left/right teeth per mouth. Two of the four groups adopted the methods of ART or fluoride-releasing resin sealant placement while the other two groups adopted the topical fluoride application methods. Fissure status of the molars in each group was evaluated every 6 months. Development of dentine caries and sealant retention over 24 months in the molars in the two sealant-using groups was compared in this report. Outcome on cost-effectiveness of all four groups over 36 months will be reported elsewhere. Results At baseline, a total of 280 children (383 molars) with mean age 7.8 years were involved for the two sealant groups. After 24 months, 261 children (357 molars) were followed. Proportions of molars with dentine caries were 7.3% and 3.9% in the ART sealant and fluoride-releasing resin sealant groups, respectively (chi-square test, p = 0.171). Life-table survival analysis showed that sealant retention (full and partial) rate over 24 months for the resin sealant (73%) was significantly higher than that (50%) for the ART sealant (p < 0.001). Molar survival (no development of dentine caries) rates in the ART sealant (93%) and fluoride-releasing resin sealant (96%) groups were not significantly different (p = 0.169). Multilevel logistic regression (GEE modeling) accounting for the effects of data clustering and confounding factors confirmed this finding. Conclusions Though the retention of fluoride

  1. Bisphenol A in dental sealants and its estrogen like effect

    PubMed Central

    Rathee, Manu; Malik, Poonam; Singh, Jyotirmay

    2012-01-01

    Bisphenol A or BPA-based epoxy resins are widely used in the manufacture of commercial products, including dental resins, polycarbonate plastics, and the inner coating of food cans. BPA is a precursor to the resin monomer Bis-GMA. During the manufacturing process of Bis-GMA dental sealants, Bisphenol A (BPA) might be present as an impurity or as a degradation product of Bis-DMA through esterases present in saliva. Leaching of these monomers from resins can occur during the initial setting period and in conjunction with fluid sorption and desorption over time and this chemical leach from dental sealants may be bioactive. Researchers found an estrogenic effect with BPA, Bis-DMA, and Bis-GMA because BPA lacks structural specificity as a natural ligand to the estrogen receptor. It generated considerable concern regarding the safety of dental resin materials. This review focuses on the BPA in dental sealants and its estrogen-like effect. PMID:22629496

  2. Exposure to fluoropolymers and VOCs during spray sealant product use.

    PubMed

    Rigler, Mark W; Longo, William E; Sauerhoff, Mitchell W

    2011-09-01

    Fluoropolymer based tile and fabric spray sealants were evaluated for the release of airborne fluoropolymer constituents and volatile organic compounds (VOCs) during typical product use scenarios in a simulated bathroom and a simulated recreational vehicle. Fluoride was quantified after oxygen bomb digestion of airborne spray collected from personal, area, and surface samples. VOCs were quantified by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/flame ionization spectrometry (GC/FID). Tile grout sealant contained approximately 1% acrylic fluoropolymer resin and 90% VOCs not including propellants. VOCs were short- and medium- chain methylated isoparaffinic hydrocarbons. When horizontally spraying a bathroom shower floor, grout spray sealant released a non-detectable amount of fluoride (<0.8 µg/m3) and 400-1400 mg/m3 total VOCs. When vertically spraying a shower wall, up to 2.0 µg/m3 of fluoride and from 1000 to 2300 mg/m3 total VOCs were detected. Fabric spray sealant contained 1% acrylic fluoropolymer resin and approximately 90% VOCs including perchloroethylene (PERC). Fabric spray released from 0.5 to 2.3 µg/m3 fluoride inside a recreational vehicle in the absence of crosswinds and less than 0.5 µg/m3 fluoride in the presence of a 10 mph crosswind. VOC release measured 240-938 mg/m3 without crosswinds and 161-522 mg/m3 with crosswinds. These studies show that fluoropolymer constituents from fluorinated spray sealants were near non-detectable levels in the breathing zone in nearly all samples while VOCs were measured at elevated levels (>400 mg/m3). The toxicological consequences of elevated VOCs during sealant spraying and the effects of certain fluoropolymer constituents are discussed. PMID:21879949

  3. Building community support for a school dental sealant program.

    PubMed

    Sanzi-Schaedel, S; Bruerd, B; Empey, G

    2001-01-01

    Children from low-income families experience more dental caries and are less likely to receive dental treatment than children from middle- and high-income families. An overwhelming amount of scientific evidence supports the effectiveness of pit and fissure sealants in deterring the development of dental caries. The authors describe a unique component of the Multnomah County, Oregon, sealant program in which local dentists volunteer to conduct dental screenings in schools. This program, which began in 1989, targets elementary schools with 40% or more of students on free or reduced-cost lunch programs. During the 1999-2000 school year, volunteer dentists screened 5,252 second- and third-grade students in 64 schools and other community programs. As a result of the screenings, dental hygienist/dental assistant teams placed a total of 11,087 dental sealants on 3,866 children (a mean of 2.87 per child). The dentists who conducted the screenings were asked to evaluate the dental sealants placed during the previous school year. The program is one example of how a school dental sealant program can be staffed to optimize the resources of a state or county public health department. An added benefit of this staffing pattern is that it builds linkages in the dental community and a foundation for collaboration between private-practice dentists and public health programs. This type of collaboration is essential to the practice of public health. Furthermore, the involvement of private dentists in a local school sealant program can contribute to the long-term oral health of low-income children. PMID:11813677

  4. Wear resistance and surface roughness of a newly devised adhesive patch for sealing smooth enamel surfaces.

    PubMed

    Schmidlin, Patrick R; Göhring, Till N; Roos, Malgorzata; Zehnder, Matthias

    2006-01-01

    A laboratory study assessed the wear resistance and surface roughness after chemical and mechanical wear of a newly devised adhesive patch when used as a smooth surface sealant. Forty-eight enamel discs were prepared from bovine lower central incisors. Sixteen specimens were treated with one of two sealing options: the prototype of an adhesive patch or a flowable resin. Unsealed enamel served as the positive control. Wear and surface roughness was measured at baseline and after all the samples were immersed in saliva or lactic acid (n=8 per treatment group) for up to 21 days, during which the experimental and control enamel surfaces were exposed to 10 double-stroke toothbrush cycles per day. In saliva and lactic acid, the sealed specimens showed no significant wear during the observation period (p=0.1841). Only untreated specimens exposed to lactic acid showed a significant substance loss after 14 and 21 days (p=0.0186). The patch and flowable resin showed no differences in surface roughness values at respective times (p=0.385); whereas the surface roughness of the unsealed specimens in lactic acid was significantly higher (p<0.0001). It was concluded that the adhesive patch under investigation merits further study to assess its potential as a sealant for smooth enamel surfaces. PMID:16536202

  5. Fentanyl Transdermal Patch

    MedlinePlus

    ... pain, pain after an operation or medical or dental procedure, or pain that can be controlled by medication that is ... transdermal patch.if you are having surgery, including dental surgery, tell the ... to prevent or treat constipation while you are using fentanyl patches.

  6. A Survey of Patch Methods

    NASA Technical Reports Server (NTRS)

    Barnhill, R. E.

    1985-01-01

    Patch methods are someshow a response to the fact that surface geometry is local, that is, only small parts of a surface are created at a time. The two categories of patches, transfinite patches and finite dimensional patches are examined and a discussion of trivariate patches is presented.

  7. Near-infrared imaging of demineralization under sealants

    PubMed Central

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

    2014-01-01

    Abstract. 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. PMID:25036214

  8. Near-IR imaging of demineralization under sealants

    PubMed Central

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

    2014-01-01

    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 cross-polarization OCT images. The wavelength region between 1500-1700-nm yielded the highest contrast of lesions under sealants for near-IR reflectance measurements. PMID:24817807

  9. TREATMENT OF WASTEWATERS FROM ADHESIVES AND SEALANTS MANUFACTURE BY ULTRAFILTRATION

    EPA Science Inventory

    Ultrafiltration was proven to be a viable unit process for separating adhesives and sealants manufacturing wastewaters into a low volume concentrate stream and a high volume permeate stream. The UF permeate was characterized by the following average contaminant loadings: 100 mg/l...

  10. 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.

  11. 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)

  12. 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.

  13. THE CONVERSION OF FIBRINOGEN TO FIBRIN

    PubMed Central

    Shulman, Sidney; Katz, Sidney; Ferry, John D.

    1953-01-01

    1. Fibrin clots prepared in the absence of calcium can be dissolved in solutions of lithium chloride and bromide and sodium bromide and iodide, as well as of guanidine hydrochloride and urea. These salts do not denature fibrinogen under the same conditions of concentration, temperature, and time. Sedimentation experiments on the fibrin solutions show in each case a single sharp peak with a sedimentation constant close to that of fibrinogen. 2. At lower concentrations, these salts inhibit the clotting of fibrinogen by thrombin, but in the case of lithium bromide and sodium iodide, at least, allow an intermediate polymer to accumulate whose sedimentation constant is close to that of the polymer observed in systems inhibited by hexamethylene glycol or urea. PMID:13069679

  14. Mechanisms of fibrin polymerization and clinical implications

    PubMed Central

    Litvinov, Rustem I.

    2013-01-01

    Research on all stages of fibrin polymerization, using a variety of approaches including naturally occurring and recombinant variants of fibrinogen, x-ray crystallography, electron and light microscopy, and other biophysical approaches, has revealed aspects of the molecular mechanisms involved. The ordered sequence of fibrinopeptide release is essential for the knob-hole interactions that initiate oligomer formation and the subsequent formation of 2-stranded protofibrils. Calcium ions bound both strongly and weakly to fibrin(ogen) have been localized, and some aspects of their roles are beginning to be discovered. Much less is known about the mechanisms of the lateral aggregation of protofibrils and the subsequent branching to yield a 3-dimensional network, although the αC region and B:b knob-hole binding seem to enhance lateral aggregation. Much information now exists about variations in clot structure and properties because of genetic and acquired molecular variants, environmental factors, effects of various intravascular and extravascular cells, hydrodynamic flow, and some functional consequences. The mechanical and chemical stability of clots and thrombi are affected by both the structure of the fibrin network and cross-linking by plasma transglutaminase. There are important clinical consequences to all of these new findings that are relevant for the pathogenesis of diseases, prophylaxis, diagnosis, and treatment. PMID:23305734

  15. Effect of Fluoridated Sealants on Adjacent Tooth Surfaces

    PubMed Central

    Cagetti, M.G.; Carta, G.; Cocco, F.; Sale, S.; Congiu, G.; Mura, A.; Strohmenger, L.; Lingström, P.; Campus, G.

    2014-01-01

    A double-blind randomized clinical trial was performed in 6- to 7-yr-old schoolchildren to evaluate, in a 30-mo period, whether the caries increment on the distal surface of the second primary molars adjacent to permanent first molars sealed with fluoride release compounds would be lower with respect to those adjacent to permanent first molars sealed with a nonfluoridated sealant. In sum, 2,776 subjects were enrolled and randomly divided into 3 groups receiving sealants on sound first molars: high-viscosity glass ionomer cement (GIC group); resin-based sealant with fluoride (fluoride-RB group); and a resin-based sealant without fluoride (RB group). Caries (D1 – D3 level) was recorded on the distal surface of the second primary molar, considered the unit of analysis including only sound surfaces at the baseline. At baseline, no differences in caries prevalence were recorded in the 3 groups regarding the considered surfaces. At follow-up, the prevalence of an affected unit of analysis was statistically lower (p = .03) in the GIC and fluoride-RB groups (p = .04). In the GIC group, fewer new caries were observed in the unit of analysis respect to the other 2 groups. Incidence rate ratios (IRRs) were 0.70 (95% confidence interval: 0.50, 0.68; p < .01) for GIC vs. RB and 0.79 (95% confidence interval: 0.53, 1.04; p = .005) for fluoride-RB vs. RB. Caries incidence was significantly associated with low socioeconomic status (IRR = 1.18; 95% confidence interval: 1.10, 1.42; p = .05). Dental sealant high-viscosity GIC and fluoride-RB demonstrated protection against dental caries, and there was evidence that these materials afforded additional protection for the tooth nearest to the sealed tooth (clinical trial registration NCT01588210). PMID:24846910

  16. 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...

  17. 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...

  18. 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...

  19. Scaffold architecture and fibrin gels promote meniscal cell proliferation

    SciTech Connect

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

    2015-01-01

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

  20. Nicotine Transdermal Patch

    MedlinePlus

    ... patches are used to help people stop smoking cigarettes. They provide a source of nicotine that reduces ... cause harm to the fetus.do not smoke cigarettes or use other nicotine products while using nicotine ...

  1. Diclofenac Transdermal Patch

    MedlinePlus

    ... and making sure not to cut the zipper seal just below it. Pull apart the zipper seal on the envelope and remove one patch. Reseal the envelope by squeezing the zipper seal together. Make sure the envelope is closed tightly ...

  2. Lidocaine Transdermal Patch

    MedlinePlus

    ... patches are used to relieve the pain of post-herpetic neuralgia (PHN; the burning, stabbing pains, or ... in your eye, wash it with plenty of water or saline solution. Wash your hands after handling ...

  3. Rotigotine Transdermal Patch

    MedlinePlus

    ... that causes difficulties with movement, muscle control, and balance) including shaking of parts of the body, stiffness, slowed movements, and problems with balance. Rotigotine transdermal patches are also used to treat ...

  4. Methylphenidate Transdermal Patch

    MedlinePlus

    ... for ADHD, which may include counseling and special education. Make sure to follow all of your doctor's ... that was covered by the patch seizures motion tics or verbal tics believing things that are not ...

  5. DyninstAPI Patches

    Energy Science and Technology Software Center (ESTSC)

    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.

  6. FNAL system patching design

    SciTech Connect

    Schmidt, Jack; Lilianstrom, Al; Romero, Andy; Dawson, Troy; Sieh, Connie; /Fermilab

    2004-01-01

    FNAL has over 5000 PCs running either Linux or Windows software. Protecting these systems efficiently against the latest vulnerabilities that arise has prompted FNAL to take a more central approach to patching systems. Due to different levels of existing support infrastructures, the patching solution for linux systems differs from that of windows systems. In either case, systems are checked for vulnerabilities by Computer Security using the Nessus tool.

  7. Tunable circular patch antennas

    NASA Astrophysics Data System (ADS)

    Lan, G.-L.; Sengupta, D. L.

    1985-10-01

    A method to control the resonant or operating frequencies of circular patch antennas has been investigated experimentally and theoretically. It consists of the placement of passive metallic or tuning posts at approximate locations within the input region of the antenna. Comparison of measured and analytical results seems to establish the validity of a theoretical model proposed to determine the input performance of such circular patch antennas.

  8. Prevalence and socioeconomic determinants of dental sealant use among schoolchildren in Saudi Arabia.

    PubMed

    Al Agili, D E; Niazy, H A; Pass, M A

    2012-12-01

    There are no published research reports on the prevalence of dental sealant use in children in Saudi Arabia. This study determined the prevalence and socioeconomic indicators of dental sealant use on the permanent molars of a stratified random sample of schoolchildren in Jeddah. A basic oral screening survey of students was conducted by dentists and a self-administered questionnaire was completed by parents. The prevalence of dental sealant use among 1668 3rd and 8th grade students was 9.0%. Students who attended public schools and those who had fathers with lowerthan high-school education were less likely to have sealants. A stepwise logistic regression model showed that socioeconomic status of school district, family's monthly income, family's type of home, having medical insurance and receiving government financial support were significantly associated with sealant use. Efforts to increase sealant use and to reduce socioeconomic disparities appear warranted in the light of high rates of dental disease. PMID:23301395

  9. 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.

  10. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Fibrin monomer paracoagulation test. 864.7300 Section 864.7300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7300 Fibrin monomer paracoagulation test....

  11. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Fibrin monomer paracoagulation test. 864.7300 Section 864.7300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7300 Fibrin monomer paracoagulation test....

  12. 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

  13. 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.

  14. 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%.

  15. 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

  16. 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.

  17. In vitro accelerated aging of composites and a sealant.

    PubMed

    Powers, J M; Fan, P L; Marcotte, M

    1981-09-01

    The in vitro accelerated aging of conventional and microfilled composite restorative materials and a sealant was studied. Volume loss/surface area ranged from 2.0 x 10(-3) mm3/mm2 for I to 7.3 x 10(-3) mm3/mm2 for SF after 900 h of aging. Surface morphology of the conventional composites was characterized by crazing and exposure of filler particles. The surfaces of the microfilled composites also showed crazing. The surface morphology of the sealant appeared unchanged. Comparisons of infrared ATR spectra between zero and 900 h of aging showed that slight chemical changes occurred at the surface of AR but not SF. PMID:6943161

  18. 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.

  19. 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.

  20. 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.

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

    PubMed Central

    Reinertsen, Erik; Skinner, Michael; Wu, Benjamin

    2014-01-01

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

  2. STS-62 crew patch

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The STS-62 crew patch depicts the world's first reusable spacecraft on its sixteenth flight. Columbia is in its entry-interface attitude as it prepares to return to Earth. The varied hues of the rainbow on the horizon connote the varied, but complementary, nature of all the payloads united on this mission. The upward-pointing vector shape of the patch is symbolic of America's reach for excellence in its unswerving pursuit to explore the frontiers of space. The brilliant sunrise just beyond Columbia suggests the promise that research in space holds for the hopes and dreams of future generations. The STS-62 insignia was designed by Mark Pestana.

  3. 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.

  4. 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. PMID:10726885

  5. Kinetics of ligation of fibrin oligomers.

    PubMed

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

    1980-07-10

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

  6. Monitoring of Sound and Carious Surfaces under Sealants over 44 Months

    PubMed Central

    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.

    2014-01-01

    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. PMID:25248613

  7. Image inpainting by patch propagation using patch sparsity.

    PubMed

    Xu, Zongben; Sun, Jian

    2010-05-01

    This paper introduces a novel examplar-based inpainting algorithm through investigating the sparsity of natural image patches. Two novel concepts of sparsity at the patch level are proposed for modeling the patch priority and patch representation, which are two crucial steps for patch propagation in the examplar-based inpainting approach. First, patch structure sparsity is designed to measure the confidence of a patch located at the image structure (e.g., the edge or corner) by the sparseness of its nonzero similarities to the neighboring patches. The patch with larger structure sparsity will be assigned higher priority for further inpainting. Second, it is assumed that the patch to be filled can be represented by the sparse linear combination of candidate patches under the local patch consistency constraint in a framework of sparse representation. Compared with the traditional examplar-based inpainting approach, structure sparsity enables better discrimination of structure and texture, and the patch sparse representation forces the newly inpainted regions to be sharp and consistent with the surrounding textures. Experiments on synthetic and natural images show the advantages of the proposed approach. PMID:20129864

  8. Nitroglycerin Transdermal Patch

    MedlinePlus

    ... verapamil (Calan, Isoptin); ergot-type medications such as bromocriptine (Parlodel), cabergoline, dihydroergotamine (D.H.E. 45, Migranal), ... at any time, especially if you have been drinking alcoholic beverages. To ... during your treatment with nitroglycerin patches.you should know that you ...

  9. Fibrin-mediated lentivirus gene transfer: implications for lentivirus microarrays

    PubMed Central

    Raut, Shruti; Lei, Pedro; Padmashali, Roshan; Andreadis, Stelios T.

    2010-01-01

    We employed fibrin hydrogel as bioactive matrix for lentivirus mediated gene transfer. Fibrin-mediated gene transfer was highly efficient and exhibited strong dependence on fibrinogen concentration. Efficient gene transfer was achieved with fibrinogen concentration between 3.75 – 7.5 mg/mL. Lower fibrinogen concentrations resulted in diffusion of virus out of the gel while higher concentrations led to ineffective fibrin degradation by target cells. Addition of fibrinolytic inhibitors decreased gene transfer in a dose-dependent manner suggesting that fibrin degradation by target cells may be necessary for successful gene delivery. Under these conditions transduction may be limited only to cells interacting with the matrix thereby providing a method for spatially localized gene delivery. Indeed, when lentivirus-containing fibrin microgels were spotted in an array format gene transfer was confined to virus-containing fibrin spots with minimal cross-contamination between neighboring sites. Collectively, our data suggest that fibrin may provide an effective matrix for spatially-localized gene delivery with potential applications in high-throughput lentiviral microarrays and in regenerative medicine. PMID:20153386

  10. 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.

  11. 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. PMID:26554545

  12. 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

    ... sealant application spray booth Reduce spray booth HAP (measured as volatile organic compounds (VOC... 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...

  13. 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

    ... sealant application spray booth Reduce spray booth HAP (measured as volatile organic compounds (VOC... 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...

  14. 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...

  15. 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

  16. 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 (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

  17. 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 (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

  18. 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 (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

  19. 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 (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

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

    PubMed Central

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

    2016-01-01

    The diagnosis of early and aggressive types of cancer is important for providing effective cancer therapy. Cancer-induced fibrin clots exist only within lesions. Previously, we developed a monoclonal antibody (clone 102-10) that recognizes insoluble fibrin but not fibrinogen or soluble fibrin and confirmed that fibrin clots form continuously in various cancers. Here, we describe the development of a Fab fragment probe of clone 102-10 for tumour imaging. The distribution of 102-10 Fab was investigated in genetically engineered mice bearing pancreatic ductal adenocarcinoma (PDAC), and its effect on blood coagulation was examined. Immunohistochemical and ex vivo imaging revealed that 102-10 Fab was distributed selectively in fibrin clots in PDAC tumours 3 h after injection and that it disappeared from the body after 24 h. 102-10 Fab had no influence on blood coagulation or fibrinolysis. Tumour imaging using anti-fibrin Fab may provide a safe and effective method for the diagnosis of invasive cancers by detecting fibrin clots in tumour stroma. PMID:27009516

  1. Argon laser curing of fluoride-releasing pit and fissure sealant: in vitro caries development.

    PubMed

    Westerman, G; Hicks, J; Flaitz, C

    2000-01-01

    The purpose of this study was to compare the effect of argon laser polymerization of a visible-light-cured, fluoride-releasing pit and fissure sealant on caries development in vitro. A total of twelve caries-free premolar and molar teeth was selected, and underwent a fluoride-free prophylaxis and soft tissue debridement. Cavity preparations were placed in buccal and lingual surfaces. Lingual cavity preparations were filled with the fluoride-releasing sealant (UltraSealXTplus, Ultradent) and visible light cured per the manufacturer's recommendation. Buccal preparations were filled with the fluoride-releasing sealant and argon laser cured (231 mW, 12 J/cm2 for 10 seconds). Following sealant placement, the teeth were sectioned into buccal and lingual halves. An acid-resistant varnish was placed leaving a 1 mm rim of exposed surface enamel adjacent to the sealant. The specimens were then thermocycled in synthetic saliva (500 cycles, 5 to 50 degrees C). In vitro caries lesions were formed (2.2 mM Ca, 2.2 mM PO4, 50 mM acetic acid, 5 ppm fluoride, pH 3.95). Longitudinal sections (five sections per tooth half) were obtained and evaluated by polarized light microscopy for mean outer surface lesion depths and frequency of wall lesions. Mean primary surface (outer) lesion depth was significantly decreased (ANOVA, DMR, P < .05) for the fluoride-releasing sealant with argon laser polymerization (152 +/- 16 um) when compared with visible light curing (211 +/- 23 um). Likewise, wall lesion frequency was substantially reduced for the argon laser polymerized sealants (17 percent) when compared with that for the visible light polymerized sealants (24 percent, ANOVA, DMR, P < .05). Argon laser polymerization of a fluoride-releasing pit and fissure sealant improved caries resistance markedly in the surface enamel adjacent to the sealant material. Argon laser curing enhanced the caries protective ability of the sealant along the enamel-resin cavosurface, as noted by a decrease in wall

  2. Platelet Rich Fibrin in Periodontal Regeneration

    PubMed Central

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

    2016-01-01

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

  3. [Patch testing: historical aspects].

    PubMed

    Lachapelle, J-M

    2009-01-01

    This article reviews the key points in the history of patch testing, which spans more than a century, starting with the first description of the method by J. Jadassohn in 1895. Special attention is paid to the contribution of French schools in this field, which led to the foundation of the Groupe d'études et de recherches en dermato-allergologie (GERDA). PMID:19686889

  4. Polymer concrete patching manual

    NASA Astrophysics Data System (ADS)

    Fontana, J. J.; Bartholomew, J.

    1982-06-01

    The practicality of using polymer concrete to repair deteriorated portland cement concrete bridge decks and pavements was demonstrated. This manual outlines the procedures for using polymer concrete as a rapid patching material to repair deteriorated concrete. The process technology, materials, equipment, and safety provisions used in manufacturing and placing polymer concrete are discussed. Potential users are informed of the various steps necessary to insure successful field applications of the material.

  5. [Treatment of pseudoarthrosis of the carpal scaphoid with fibrin glue].

    PubMed

    Carozzi, S

    1983-08-01

    The author think that "Fibrin Seal Glue" and mechanical syntesis is an opimal method for osteosintesis of the Carpal scaphoid. He speaks about 5 patients treated with optimal results in 50 days mean. PMID:6395974

  6. Growing vortex patches

    NASA Astrophysics Data System (ADS)

    Crowdy, Darren; Marshall, Jonathan

    2004-08-01

    This paper demonstrates that two well-known equilibrium solutions of the Euler equations—the corotating point vortex pair and the Rankine vortex—are connected by a continuous branch of exact solutions. The central idea is to "grow" new vortex patches at two stagnation points that exist in the frame of reference of the corotating point vortex pair. This is done by generalizing a mathematical technique for constructing vortex equilibria first presented by Crowdy [D. G. Crowdy, "A class of exact multipolar vortices," Phys. Fluids 11, 2556 (1999)]. The solutions exhibit several interesting features, including the merging of two separate vortex patches via the development of touching cusps. Numerical contour dynamics methods are used to verify the mathematical solutions and reveal them to be robust structures. The general issue of how simple vortex equilibria can be continued continuously to more complicated ones with very different vortical topologies is discussed. The solutions are examples of exact solutions of the Euler equations involving multiple interacting vortex patches.

  7. Caries-preventive effect of fissure sealants: a systematic review.

    PubMed

    Mejàre, Ingegerd; Lingström, Peter; Petersson, Lars G; Holm, Anna-Karin; Twetman, Svante; Källestål, Carina; Nordenram, Gunilla; Lagerlöf, Folke; Söder, Birgitta; Norlund, Anders; Axelsson, Susanna; Dahlgren, Helena

    2003-12-01

    The objectives of this study were to evaluate systematically the evidence of the caries-preventive effect of fissure sealing of occlusal tooth surfaces and to examine factors potentially modifying the effect. The search strategies included electronic databases, reference lists of articles, and selected textbooks. Inclusion criteria were randomized or quasi-randomized clinical trials or controlled clinical trials comparing fissure sealing with no treatment or another preventive treatment in children up to 14 years of age at the start; the outcome measure was caries increment; the diagnostic criteria had been described; and the follow-up time was at least 2 years. Inclusion decisions were taken and grading of the studies was done independently by two of the authors. The main measure of effect was relative risk reduction. Thirteen studies using resin-based or glass ionomer sealant materials were included in the final analysis. The results showed that most studies were performed during the 1970s and a single application had been utilized. The relative caries risk reduction pooled estimate of resin-based sealants on permanent 1st molars was 33% (relative risk = 0.67; CI = 0.55-0.83). The effect depended on retention of the sealant. In conclusion, the review suggests limited evidence that fissure sealing of 1st permanent molars with resin-based materials has a caries-preventive effect. The evidence is incomplete for permanent 2nd molars, premolars and primary molars and for glass ionomer cements. Overall, there remains a need for further trials of high quality, particularly in child populations with a low and a high caries risk, respectively. PMID:14960003

  8. Con-Patch: When a Patch Meets Its Context.

    PubMed

    Romano, Yaniv; Elad, Michael

    2016-09-01

    Measuring the similarity between the patches in images is a fundamental building block in various tasks. Naturally, the patch size has a major impact on the matching quality and on the consequent application performance. Under the assumption that our patch database is sufficiently sampled, using large patches (e.g., 21 × 21 ) should be preferred over small ones (e.g., 7 × 7 ). However, this dense-sampling assumption is rarely true; in most cases, large patches cannot find relevant nearby examples. This phenomenon is a consequence of the curse of dimensionality, stating that the database size should grow exponentially with the patch size to ensure proper matches. This explains the favored choice of small patch size in most applications. Is there a way to keep the simplicity and work with small patches while getting some of the benefits that large patches provide? In this paper, we offer such an approach. We propose to concatenate the regular content of a conventional (small) patch with a compact representation of its (large) surroundings-its context. Therefore, with a minor increase of the dimensions (e.g., with additional ten values to the patch representation), we implicitly/softly describe the information of a large patch. The additional descriptors are computed based on a self-similarity behavior of the patch surrounding. We show that this approach achieves better matches, compared with the use of conventional-size patches, without the need to increase the database-size. Also, the effectiveness of the proposed method is tested on three distinct problems: 1) external natural image denoising; 2) depth image super-resolution; and 3) motion-compensated frame-rate up conversion. PMID:27295669

  9. Con-Patch: When a Patch Meets Its Context

    NASA Astrophysics Data System (ADS)

    Romano, Yaniv; Elad, Michael

    2016-09-01

    Measuring the similarity between patches in images is a fundamental building block in various tasks. Naturally, the patch-size has a major impact on the matching quality, and on the consequent application performance. Under the assumption that our patch database is sufficiently sampled, using large patches (e.g. 21-by-21) should be preferred over small ones (e.g. 7-by-7). However, this "dense-sampling" assumption is rarely true; in most cases large patches cannot find relevant nearby examples. This phenomenon is a consequence of the curse of dimensionality, stating that the database-size should grow exponentially with the patch-size to ensure proper matches. This explains the favored choice of small patch-size in most applications. Is there a way to keep the simplicity and work with small patches while getting some of the benefits that large patches provide? In this work we offer such an approach. We propose to concatenate the regular content of a conventional (small) patch with a compact representation of its (large) surroundings - its context. Therefore, with a minor increase of the dimensions (e.g. with additional 10 values to the patch representation), we implicitly/softly describe the information of a large patch. The additional descriptors are computed based on a self-similarity behavior of the patch surrounding. We show that this approach achieves better matches, compared to the use of conventional-size patches, without the need to increase the database-size. Also, the effectiveness of the proposed method is tested on three distinct problems: (i) External natural image denoising, (ii) Depth image super-resolution, and (iii) Motion-compensated frame-rate up-conversion.

  10. 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

  11. 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

  12. Alterations in Fibrin Structure in Patients with Liver Diseases.

    PubMed

    Lisman, Ton; Ariëns, Robert A S

    2016-06-01

    The hemostatic balance in patients with liver diseases is relatively well preserved due to concomitant alterations in pro- and antihemostatic pathways. Thrombin generation studies support the notion of hemostatic competence in liver diseases, but in such tests alterations in fibrinogen level and function are not taken into account. We have recently studied structural and functional properties of the fibrin clot in patients with liver diseases. Although we have confirmed previous findings that hypersialylation of the fibrinogen molecule in patients with liver diseases contributes to a defective fibrinogen-to-fibrin conversion, we have found that once the clot has been formed, it has a thrombogenic nature as assessed by permeability assays. These thrombogenic properties of the fibrin clot in cirrhosis relate to incompletely characterized intrinsic changes in the fibrinogen molecule, which may include oxidation and hypersialylation. In addition, in patients with nonalcoholic fatty liver disease thrombogenic properties of the fibrin clot are not only due to liver disease but also to obesity and the metabolic syndrome. During liver transplantation, the clot normalizes and becomes increasingly permeable, and the functional properties of the fibrin clot are markedly normalized by fibrinogen concentrate, when added to plasma samples in vitro. These new insights in the functional properties of the fibrin clot in patients with liver diseases facilitate a more rational approach to treatment and prevention of both bleeding and thrombotic complications. PMID:27071046

  13. Multivalent Viral Capsids with Internal Cargo for Fibrin Imaging

    PubMed Central

    Obermeyer, Allie C.; Capehart, Stacy L.; Jarman, John B.; Francis, Matthew B.

    2014-01-01

    Thrombosis is the cause of many cardiovascular syndromes and is a significant contributor to life-threatening diseases, such as myocardial infarction and stroke. Thrombus targeted imaging agents have the capability to provide molecular information about pathological clots, potentially improving detection, risk stratification, and therapy of thrombosis-related diseases. Nanocarriers are a promising platform for the development of molecular imaging agents as they can be modified to have external targeting ligands and internal functional cargo. In this work, we report the synthesis and use of chemically functionalized bacteriophage MS2 capsids as biomolecule-based nanoparticles for fibrin imaging. The capsids were modified using an oxidative coupling reaction, conjugating ∼90 copies of a fibrin targeting peptide to the exterior of each protein shell. The ability of the multivalent, targeted capsids to bind fibrin was first demonstrated by determining the impact on thrombin-mediated clot formation. The modified capsids out-performed the free peptides and were shown to inhibit clot formation at effective concentrations over ten-fold lower than the monomeric peptide alone. The installation of near-infrared fluorophores on the interior surface of the capsids enabled optical detection of binding to fibrin clots. The targeted capsids bound to fibrin, exhibiting higher signal-to-background than control, non-targeted MS2-based nanoagents. The in vitro assessment of the capsids suggests that fibrin-targeted MS2 capsids could be used as delivery agents to thrombi for diagnostic or therapeutic applications. PMID:24960118

  14. Platelet-derived microparticles associate with fibrin during thrombosis.

    PubMed

    Siljander, P; Carpen, O; Lassila, R

    1996-06-01

    Platelet-derived microparticles (MP) are reported to express both pro- and anticoagulant activities. Nevertheless, their functional significance has remained unresolved. The present study monitored the generation and fate of MP in an experimental model of thrombosis with costimulation of platelets by collagen and thrombin. When minimally anticoagulated (0.5 micromol/L PPACK) blood was perfused over immobilized fibrillar type I collagen in a flow chamber at a low shear rate (300 s(-1)), endogenous thrombin was generated, as evidenced by thrombin-antithrombin III complex. In contrast to full anticoagulation 150 micromol/L PPACK) and the absence of collagen, large platelet aggregates and fibrin ensued during perfusions over collagen in the presence of thrombin. In these thrombi, MP, defined as GPIIbIIIa- and P-selectin-positive vesicles (<1 micron), were found to align fibrin in immunofluorescence and scanning immunoelectron microscopy. Moreover, in sections of embolectomized thromboemboli from patients GPIIbIIIa- and P-selectin-positive material compatible with MP was detected in a fibrin strand-like pattern. In vitro binding studies showed that MP bound to fibrin and acted there as procoagulants. In summary, we show that MP generated during thrombus formation associate with local fibrin. This adhesive function fibrin could imply a sustained modulatory role for MP in evolving thrombi. PMID:8639834

  15. 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

  16. The sustained release of cefotaxim from a fibrin-cefotaxim compound in treatment of osteitis. Pharmacokinetic study and clinical results.

    PubMed

    Zilch, H; Lambiris, E

    1986-01-01

    Following a survey of the literature regarding clinical examinations and experimental studies of local absorbable carrier for an antibiotic in treatment of osteitis, a study is presented concerning clinical experience with 46 patients treated with a cefotaxim-loaded fibrin sealant. In connection with simultaneous focal sanitation the clinical results were satisfying. When autogenous cancellous bone was added at the same time, only one surgical operation was necessary in some cases to show results equivalent to other methods. Postoperatively, the cefotaxim levels in the blood and in the wound drainage fluid were measured. The serum cefotaxim concentrations were low and only identifiable for a period of 36h, whereas the wound drainage fluid contained very highly effective antibacterial concentrations over a measured period of 3.5 days. The best results were seen in cases of hematogenic osteomyelitis. The disadvantage of this system is the quick release of the antibiotic by diffusion. Therefore, high concentrations can be obtained only for a short period of several days. PMID:3551877

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

    DOEpatents

    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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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

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

    PubMed

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

    2016-03-01

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

  4. 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. PMID:25982442

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

    PubMed

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

    2014-06-01

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

  6. 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.

  7. Tiling Motion Patches.

    PubMed

    Hyun, Kyunglyul; Kim, Manmyung; Hwang, Youngseok; Lee, Jehee

    2013-05-01

    Simulating multiple character interaction is challenging because character actions must be carefully coordinated to align their spatial locations and synchronized with each other. We present an algorithm to create a dense crowd of virtual characters interacting with each other. The interaction may involve physical contacts, such as hand shaking, hugging, and carrying a heavy object collaboratively. We address the problem by collecting deformable motion patches, each of which describes an episode of multiple interacting characters, and tiling them spatially and temporally. The tiling of motion patches generates a seamless simulation of virtual characters interacting with each other in a non-trivial manner. Our tiling algorithm uses a combination of stochastic sampling and deterministic search to address the discrete and continuous aspects of the tiling problem. Our tiling algorithm made it possible to automatically generate highly-complex animation of multiple interacting characters. We achieved the level of complexity far beyond the current state-of-the-art animation techniques could generate, in terms of the diversity of human behaviors and the spatial/temporal density of interpersonal interactions. PMID:23669532

  8. Tiling motion patches.

    PubMed

    Hyun, Kyunglyul; Kim, Manmyung; Hwang, Youngseok; Lee, Jehee

    2013-11-01

    Simulating multiple character interaction is challenging because character actions must be carefully coordinated to align their spatial locations and synchronized with each other. We present an algorithm to create a dense crowd of virtual characters interacting with each other. The interaction may involve physical contacts, such as hand shaking, hugging, and carrying a heavy object collaboratively. We address the problem by collecting deformable motion patches, each of which describes an episode of multiple interacting characters, and tiling them spatially and temporally. The tiling of motion patches generates a seamless simulation of virtual characters interacting with each other in a nontrivial manner. Our tiling algorithm uses a combination of stochastic sampling and deterministic search to address the discrete and continuous aspects of the tiling problem. Our tiling algorithm made it possible to automatically generate highly complex animation of multiple interacting characters. We achieve the level of interaction complexity far beyond the current state of the art that animation techniques could generate, in terms of the diversity of human behaviors and the spatial/temporal density of interpersonal interactions. PMID:24029911

  9. 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.

  10. 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.

  11. Effect of One Percent Chlorhexidine Addition on the Antibacterial Activity and Mechanical Properties of Sealants: An in vitro Study

    PubMed Central

    Asokan, Sharath; John, J Baby; Priya, PR Geetha; Devi, Jagadeesan Gnana

    2015-01-01

    ABSTRACT Aim: The aim of the study was to evaluate the effect of addition of 1% chlorhexidine digluconate solution on the antibacterial activity and mechanical properties of glass ionomer and resin based sealant. Materials and methods: Conventional glass ionomer sealant (GIS) (Fuji VII, Japan) and resin sealant (Clinpro 3M ESPE, USA) were used in this study. Chlorhexidine digluconate (CHX) (20%) liquid was added to both the sealants, and the concentration of chlorhexidine in sealants was adjusted to 1%. The sealants were divided into four groups as: group A (GIS), group B (GIS + 1% CHX), group C (resin sealant), group D (resin sealant + 1% CHX). Five cylindrical specimens were prepared in each group. Their antibacterial activity against Streptococcus mutans and Lactobacillus acidophilus, and their mechanical properties (compressive strength and diametrical tensile strength) were assessed. Mann-Whitney and Wilcoxon signed rank test were used appropriately for statistical analysis (SPSS version 19). Result: Addition of one percent chlorhexidine significantly increased the antibacterial activity of both the sealants. There was a significant difference between groups A and B (p < 0.009), and groups C and D (p < 0.008). There was no significant difference in the mechanical properties of the sealants. Conclusion: Addition of one percent chlorhexidine to the glass ionomer and resin based sealants provided sufficient antibacterial activity, without significantly affecting the mechanical property of the sealants. How to cite this article: Shanmugaavel AK, Asokan S, John JB, Geetha Priya PR, Gnana Devi J. Effect of one percent Chlorhexidine Addition on the Antibacterial Activity and Mechanical Properties of Sealants: An in vitro Study. Int J Clin Pediatr Dent 2015;8(3):196-201. PMID:26628854

  12. 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.

  13. Fibrin gel as alternative scaffold for respiratory tissue engineering.

    PubMed

    Cornelissen, Christian G; Dietrich, Maren; Krüger, Stefan; Spillner, Jan; Schmitz-Rode, Thomas; Jockenhoevel, Stefan

    2012-03-01

    Fibrin gel has proven a valuable scaffold for tissue engineering. Complex geometries can be produced by injection molding; it offers effective cell seeding and can be produced autologous. In order to evaluate its suitability for respiratory tissue engineering, we examined proliferation, functionality, and differentiation of respiratory epithelial cells on fibrin gel in comparison to culture on collagen-coated, microporous membranes. Respiratory epithelial cells formed a confluent layer by day 4, and proliferation showed no significant difference with respect to surface. Measurement of the transepithelial electrical resistance reflected the development of a confluent epithelial cell layer and the subsequent initiation of adequate ion-transfer processes. Appearance of ciliae could be detected at similar time points, and ciliary beating could be observed for cells on both surfaces. Histology and immunohistochemistry of cells grown on fibrin gel revealed the onset of adequate differentiation. As no significant differences in respiratory epithelial cells' proliferation, function, and differentiation could be observed between cells grown on fibrin gel compared to cells on a collagen-coated, microporous surface, we concluded that fibrin gel might prove a suitable scaffold for respiratory tissue engineering and merits further investigation to overcome the limitations associated with scaffolds currently in use. PMID:22009317

  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. 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

  16. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant and... depressions (faults in the enamel) in the biting surfaces of teeth to prevent cavities. (b)...

  17. Bright patches on Ariel

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Distinct bright patches are visible on Ariel, the brightest of Uranus' five largest satellites. Voyager 2 obtained this image Jan. 22, 1986, from a distance of 2.52 million kilometers (1.56 million miles). The clear-filter image, obtained with the narrow-angle camera, shows a resolution of 47 km (29 miles). Ariel is about 1,300 km (800 mi) in diameter. This image shows several distinct bright areas that reflect nearly 45 percent of the incident sunlight; on average, the satellite displays a reflectivity of about 25-30 percent. The bright areas are probably fresh water ice, perhaps excavated by impacts. The south pole of Ariel is slightly off center of the disk in this view. Voyager 2 will obtain its best views of the satellite on Jan. 24, at a closest-approach distance of 127,000 km (79,000 mi). The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

  18. Granuloma annulare, patch type.

    PubMed

    Victor, Frank C; Mengden, Stephanie

    2008-01-01

    A 64-year-old man was referred to the Bellevue Hospital Center Dermatology Clinic for evaluation of an asymptomatic eruption on his left inner arm, which had been present for 4 months and was unresponsive to topical anti-fungal therapy. One month after the initial eruption, 2 similar, asymptomatic lesions appeared on the right inner arm. The lesions were slowly expanding. A biopsy specimen from the left medial arm was consistent with interstitial granuloma annulare. The patient's clinical presentation was consistent with patch-type granuloma annulare. He was treated with a mid-potency topical glucocorticoid twice daily for 4 weeks without benefit. Since the eruption was asymptomatic, treatment was discontinued. PMID:18627757

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

    PubMed Central

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

    2016-01-01

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

  20. 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.

  1. 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

  2. Evidence not practised: the underutilisation of preventive fissure sealants.

    PubMed

    Bonetti, D L

    2014-04-01

    International and UK professional organisations, Cochrane systematic reviews, and international and UK guidance documents all support the application of preventive fissure sealants (PFSs) as an effective treatment for reducing caries. However, PFSs are well known to be underutilised in primary care. This paper collates data from PFS-relevant studies in Scotland, which has a large population of children at caries risk, to identify the beliefs and factors dentists perceive as influencing their decision not to provide this treatment. This information provides a platform to suggest how to increase the application of PFSs in this region (a standardised audit incorporating evidence-based behaviour change techniques, supplemental guidance on how to implement gold-standard recommendations in practice, training). This may also be relevant outside of Scotland, as well as to the implementation of other evidence-based behaviours in practice. PMID:24722094

  3. Inosculation and perfusion of pre-vascularized tissue patches containing aligned human microvessels after myocardial infarction.

    PubMed

    Riemenschneider, Sonja B; Mattia, Donald J; Wendel, Jacqueline S; Schaefer, Jeremy A; Ye, Lei; Guzman, Pilar A; Tranquillo, Robert T

    2016-08-01

    A major goal of tissue engineering is the creation of pre-vascularized tissues that have a high density of organized microvessels that can be rapidly perfused following implantation. This is especially critical for highly metabolic tissues like myocardium, where a thick myocardial engineered tissue would require rapid perfusion within the first several days to survive transplantation. In the present work, tissue patches containing human microvessels that were either randomly oriented or aligned were placed acutely on rat hearts post-infarction and for each case it was determined whether rapid inosculation could occur and perfusion of the patch could be maintained for 6 days in an infarct environment. Patches containing self-assembled microvessels were formed by co-entrapment of human blood outgrowth endothelial cells and human pericytes in fibrin gel. Cell-induced gel contraction was mechanically-constrained resulting in samples with high densities of microvessels that were either randomly oriented (with 420 ± 140 lumens/mm(2)) or uniaxially aligned (with 940 ± 240 lumens/mm(2)) at the time of implantation. These patches were sutured onto the epicardial surface of the hearts of athymic rats following permanent ligation of the left anterior descending artery. In both aligned and randomly oriented microvessel patches, inosculation occurred and perfusion of the transplanted human microvessels was maintained, proving the in vivo vascularization potential of these engineered tissues. No difference was found in the number of human microvessels that were perfused in the randomly oriented (111 ± 75 perfused lumens/mm(2)) and aligned (173 ± 97 perfused lumens/mm(2)) patches. Our results demonstrate that tissue patches containing a high density of either aligned or randomly oriented human pre-formed microvessels achieve rapid perfusion in the myocardial infarct environment - a necessary first-step toward the creation of a thick, perfusable heart patch. PMID

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

    PubMed

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

    2009-01-01

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

  5. Fibrin self-assembly is adapted to oxidation.

    PubMed

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

    2016-06-01

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

  6. Arthroscopic repair of acetabular chondral delamination with fibrin adhesive.

    PubMed

    Tzaveas, Alexandros P; Villar, Richard N

    2010-01-01

    Acetabular chondral delamination is a frequent finding at hip arthroscopy. The cartilage is macroscopically normal but disrupted from the subchondral bone. Excision of chondral flaps is the usual procedure for this type of lesion. However, we report 19 consecutive patients in whom the delaminated chondral flap was re-attached to the underlying subchondral bone with fibrin adhesive. We used the modified Harris hip score for assessment of pain and function. Improvement in pain and function was found to be statistically significant six months and one year after surgery. No local or general complications were noted. Three patients underwent further surgery for unrelated reasons. In each, the area of fibrin repair appeared intact and secure. Our results suggest that fibrin is a safe agent to use for acetabular chondral delamination. PMID:20235074

  7. One-year clinical evaluation of a Glass Carbomer fissure sealant, a preliminary study.

    PubMed

    Gorseta, K; Glavina, D; Borzabadi-Farahani, A; Van Duinen, R N; Skrinjaric, I; Hill, R G; Lynch, E

    2014-06-01

    Glass Carbomer is a new generation of restorative material developed from glass-ionomer cements with possibility of gradual mineralization into fluorapatite. The aim of this clinical trial was to investigate the retention of Glass Carbomer fissure sealant after 12 months, in comparison to a commonly used conventional resin-based sealant. Forty-eight teeth in 24 patients [mean (SD) = 8 (2.3) years] with well-delineated fissure morphology were randomly divided into two equal groups and sealed with Bis-GMA resin-based Helioseal F (group A, Ivoclar Vivadent, Liechtenstein) and Glass Carbomer (group B, Glass Carbomer Sealant, Glass Carbomer Products, Leiden, Netherlands) using the split mouth design. Materials were placed and set according to the manufacturer's instructions using a polymerization unit Bluephase 16i (Vivadent, Liechtenstein). Complete sealant retentions in both groups were 100% and 75% after 6 and 12 months of clinical service, respectively. There were there were no secondary caries lesions in both groups after 6 months; two new carious lesions were detected in both groups after 12 months. The Mann-Whitney U test revealed no significant difference between the two groups at both evaluations points (P > 0.05). Glass Carbomer material showed a similar retention rate when compared with a resin-based sealant. Future studies are required to examine the long-term performance of Glass Carbomer sealants. PMID:25134364

  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. PMID:26282541

  9. 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

  10. Stability of patch test allergens.

    PubMed

    Joy, Nicole Marie; Rice, Kristen R; Atwater, Amber Reck

    2013-01-01

    Patch testing is widely used in evaluating suspected contact dermatitis. One major component of a quality patch test result is a dependable, predictable allergen supply. The allergen needs to be present at a sufficient concentration to elicit a reaction in an allergic patient. To better understand the stability of patch-test allergens, we completed a systematic review of the literature. We found that there is variability in stability among patch-test allergens and that although a few have been shown to be stable, many degrade when in storage. In most cases, expiration dates should be honored. In addition, allergen panels should be prepared as close to the time of patch test application as is possible. PMID:24030367

  11. 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 ...

  12. The effects of fibrin tissue adhesive on the middle ear.

    PubMed

    Katzke, D; Pusalkar, A; Steinbach, E

    1983-02-01

    This study investigated the effects of fibrin glue ('Tissucol', Immuno Pty. Ltd.) in the middle and inner ear. Small amounts of the adhesive were used in 36 operations performed on 18 rabbits. The light microscopic examination of these ears four, eight and 12 weeks after surgery showed that the adhesive was well tolerated and that it did not have any toxic effect on the middle ear or membranous labyrinth. The fibrin tissue adhesive can therefore safely be used to facilitate reconstructive middle-ear surgery and, with the aid of fascia, also for the closure of labyrinthine fistulae; or to achieve a definite seal of oval window niche after stapes surgery. PMID:6600776

  13. Standard operating procedure (SOP) for the quantitative determination of organic silicon compounds at the surface of elastomeric sealants

    NASA Astrophysics Data System (ADS)

    Gross, Th; Treu, D.; Unger, W.

    2001-07-01

    Elastomeric sealants may contain organic silicon compounds. The use of these sealants for housings for electronic components is harmful for the reliability of electric contacts inside. In order to prevent electronic components from malfunction, quality control of elastomeric sealants is required. An analytical procedure developed to fulfil this requirement was developed. It is based on electron spectroscopy for chemical analysis (ESCA). Information on the silicon compounds existing at the surface of elastomeric sealants is provided by this method. Silicon in organic and inorganic compounds can be differentiated with the help of Si 2p photoelectron spectra. Quantitative results can be obtained too. The uncertainty budget of the quantitative procedure is estimated.

  14. Adhesion mechanisms of bituminous crack sealant to aggregate and laboratory test development

    NASA Astrophysics Data System (ADS)

    Hajialiakbari Fini, Elham

    Crack sealing is a common pavement maintenance treatment because it extends pavement service life. However, crack sealant often fails prematurely due to a loss of adhesion. Since current test methods are mostly empirical and only provide a qualitative measure of bond strength, they cannot predict sealant adhesive failure accurately. Hence, there is an urgent need for test methods based on bituminous sealant rheology that can better predict sealant field performance. This study introduces three laboratory tests aimed to assess the bond property of hot-poured crack sealant to pavement crack walls. The three tests are designed to serve the respective needs of producers, engineers, and researchers. The first test implements the principle of surface energy to measure the thermodynamic work of adhesion, which is the energy spent in separating the two materials at the interface. The work of adhesion is reported as a measure of material compatibility at an interface. The second test is a direct adhesion test, a mechanical test which is designed to closely resemble both the installation process and the crack expansion due to thermal loading. This test uses the Direct Tension Test (DTT) device. The principle of the test is to apply a tensile force to detach the sealant from its aggregate counterpart. The maximum load, Pmax, and the energy to separation, E, are calculated and reported to indicate interface bonding. The third test implements the principles of fracture mechanics in a pressurized circular blister test. The apparatus is specifically designed to conduct the test for bituminous crack sealant, asphalt binder, or other bitumen-based materials. In this test, a fluid is injected at a constant rate at the interface between the substrate (aggregate or a standard material) and the adhesive (crack sealant) to create a blister. The fluid pressure and blister height are measured as functions of time; the data is used to calculate Interfacial Fracture Energy (IFE), which is a

  15. Edge of polar cap patches

    NASA Astrophysics Data System (ADS)

    Hosokawa, K.; Taguchi, S.; Ogawa, Y.

    2016-04-01

    On the night of 4 December 2013, a sequence of polar cap patches was captured by an all-sky airglow imager (ASI) in Longyearbyen, Norway (78.1°N, 15.5°E). The 630.0 nm airglow images from the ASI of 4 second exposure time, oversampled the emission of natural lifetime (with quenching) of at least ˜30 sec, introduce no observational blurring effects. By using such high-quality ASI images, we succeeded in visualizing an asymmetry in the gradients between the leading/trailing edges of the patches in a 2-D fashion. The gradient in the leading edge was found to be 2-3 times steeper than that in the trailing edge. We also identified fingerlike structures, appearing only along the trailing edge of the patches, whose horizontal scale size ranged from 55 to 210 km. These fingers are considered to be manifestations of plasma structuring through the gradient-drift instability (GDI), which is known to occur only along the trailing edge of patches. That is, the current 2-D observations visualized, for the first time, how GDI stirs the patch plasma and such a mixing process makes the trailing edge more gradual. This result strongly implies a close connection between the GDI-driven plasma stirring and the asymmetry in the large-scale shape of patches and then suggests that the fingerlike structures can be used as markers to estimate the fine-scale structure in the plasma flow within patches.

  16. 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

  17. Comparative evaluation of the biological properties of fibrin for bone regeneration

    PubMed Central

    Oh, Joung-Hwan; Kim, Hye-Jin; Kim, Tae-Il; Woo, Kyung Mi

    2014-01-01

    Fibrin is a natural provisional matrix found in wound healing, while type I collagen is a major organic component of bone matrix. Despite the frequent use of fibrin and type I collagen in bone regenerative approaches, their comparative efficacies have not yet been evaluated. In the present study, we compared the effects of fibrin and collagen on the proliferation and differentiation of osteoblasts and protein adsorption. Compared to collagen, fibrin adsorbed approximately 6.7 times more serum fibronectin. Moreover, fibrin allowed the proliferation of larger MC3T3-E1 pre-osteoblasts, especially at a low cell density. Fibrin promoted osteoblast differentiation at higher levels than collagen, as confirmed by Runx2 expression and transcriptional activity, alkaline phosphatase activity, and calcium deposition. The results of the present study suggest that fibrin is superior to collagen in the support of bone regeneration. [BMB Reports 2014; 47(2): 110-114] PMID:24257120

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

    PubMed

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

    2013-04-01

    The potential of synthesizing new nanocomposites from nanocrystalline cellulose (NCC) and fibrin for small-diameter replacement vascular graft (SDRVG) application was demonstrated. Periodate oxidation of NCC can augment reactive carbonyl groups on NCC and facilitate its cross-linking with fibrin. NCC-fibrin nanocomposites were synthesized, composed of homogeneously dispersed oxidized NCC (ONCC) in a fibrin matrix, with fibrin providing elasticity and ONCC providing strength. The maximum strength and elongation of the nanocomposites were determined by Atomic Force Microscopy (AFM) and compared with a native blood vessel. The manipulation of degree of oxidation of NCC and the NCC-to-fibrin ratio resulted in the variation of strength and elongation of the nanocomposites, indicating that the nanocomposites can be tailored to conform to the diverse mechanical properties of native blood vessels. A mechanistic understanding of the molecular interactions of ONCC and fibrin was illustrated. This study established fundamental information to utilizing NCC for SDRVG applications. PMID:23421631

  19. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

  1. Oriented fibrin gels formed by polymerization in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Torbet, J.

    1981-01-01

    Fibrinogen is a soluble plasma protein which, after cleavage by the specific proteolytic enzyme thrombin, polymerizes to form the filamentous fibrin network during blood clotting (see refs 1 and 2 for reviews). Fibrinogen has a molecular weight of 340,000 and is composed of two identical halves, each containing three peptide chains designated Aα, Bβ and γ. Fibrin monomers are produced by thrombin which releases the small negatively charged fibrinopeptides A and B. The overall shape of the fibrinogen molecule has not been unequivocally established1,2. The trinodular, elongated (~450 Å long) structure proposed by Hall and Slayter3 is the most widely accepted model and it has obtained additional support from recent work4-6. Fibrin monomers are also about 450 Å long7 and in fibres they probably have a half-staggered arrangement along the axis7,8. The fibres are an assembly of protofibrils whose structure and packing are not reliably known. We report here that highly oriented fibrin gels are formed when polymerization takes place slowly in a strong magnetic field. It is shown that the protofibrils pack into a three-dimensional crystalline lattice. We introduce magnetically induced birefringence as a potential tool for studying polymerization and briefly speculate on the applications of strong magnetic fields.

  2. Cutaneous collagenous vasculopathy associated with intravascular occlusive fibrin thrombi.

    PubMed

    Salama, Samih; Chorneyko, Kathy; Belovic, Brian

    2014-04-01

    Cutaneous collagenous vasculopathy (CCV) is a rare cutaneous microangiopathy that clinically resembles generalized essential telangiectasia with only 12 cases reported to date. The perivascular fibrosis is thought to be due to production of abnormal collagen by veil cells in the outer vessel walls as a result of unknown factors. This report is of an 84-year-old male with progressive telangiectasia. Biopsies showed characteristic features of CCV. In addition, there were multiple intravascular fibrin thrombi, some organizing and associated with endothelial cell hyperplasia with recanalization reminiscent of glomeruloid bodies and simulating reactive angioendotheliomatosis (RAE). Histochemically and ultrastructurally fibrin was noted within the vessel walls integrating into the fibrous tissue around the vessels; however, the patient had no evidence of coagulation disorder, cryoglobulinemia or cold agglutinemia. Immunofluorescence showed fibrinogen within the vessel walls but no immunoglobulins or C3. As well, there were minimal inflammatory cells. This suggests pauci-inflammatory injury to the endothelial cells by unknown angiogenic factors causing local intravascular fibrin thrombi with fibrin leaking and incorporating into the vessel walls, eventually leading to reparative perivascular fibrosis. This case suggests that some cases of CCV are related to a primary local intravascular occlusive thrombotic microangiopathy. However, the primary triggering factor causing the endothelial cell damage has yet to be elucidated. PMID:24350781

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

    NASA Astrophysics Data System (ADS)

    Lobanov, A. I.

    2016-06-01

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

  4. Successful management of congenital chyloperitoneum with fibrin glue.

    PubMed

    Antao, Brice; Croaker, David; Squire, Roly

    2003-11-01

    Chylous ascites in children has been treated in a variety of ways, including a low-fat diet, medium chain triglycerides, diuretics, total parental nutrition, surgical exploration, and internal peritoneo-venous shunting. The authors describe a child with persistent congenital chyloperitoneum treated successfully with the application of fibrin glue and recommend this as an effective alternative to traditional approaches. PMID:14614734

  5. Selective removal of composite sealants with near-UV laser pulses

    NASA Astrophysics Data System (ADS)

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

    2004-05-01

    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 lasers pulses from a frequency-tripled Nd:YAG laser (355-nm) can selectively remove residual composite after orthodontic bracket removal on enamel surfaces. UV laser light is preferentially absorbed by polymeric resins and the organic content of the tooth enamel. The objective of this study was to determine if such laser pulses are suitable for selective removal of the old composite from pit and fissure sealants and restorations without damaging surrounding sound tissues. Optical coherence tomography was used to acquire optical cross sections of the occlusal topography and peripheral tooth structure non-destructively before application of the sealants, after sealant application, and after sealant removal with 355-nm laser pulses with intensities ranging from 0-10 J/cm2. Thermocouples were used to monitor the temperature in the pulp chamber during composite removal under clinically relevant ablation rates, i.e., 30 Hz and 30 mJ per laser pulse. At an irradiation intensity of 1.3 J/cm2 pit and fissure sealants were completely removed without visible damage to the underlying enamel. At intensities above 1.5 J/cm2, the laser removes the resin layer while at the same time preferentially etching the surface of the enamel. Temperature excursions in the pulp chamber of extracted teeth was limited to less than 5°C if air-cooling was used during the rapid removal (1-2 min) of sealants, water-cooling was not needed. This is the first presentation of a method for the selective removal of composite restorative materials without damage to the underlying sound tooth structure.

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

    PubMed Central

    Bernik, Maria B.

    1973-01-01

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

  7. Creation of polar cap patches

    NASA Astrophysics Data System (ADS)

    Hosokawa, K.; Taguchi, S.; Ogawa, Y.

    2014-12-01

    Polar cap patches, which are islands of enhanced plasma density drifting anti-sunward, are one of the outstanding phenomena in the polar cap F region ionosphere. In the last decade, data from all-sky airglow imagers have been extensively used for better understanding the propagation of patches in the central polar cap region. But still, it has been rather difficult to capture the birth of patches in their generation region near the dayside cusp, because, in most places, the dayside part of the polar cap ionosphere is sunlit even in winter. In Longyearbyen (78.1N, 15.5E), Norway, however, optical observations are possible near the dayside cusp region in a limited period around the winter solstice. This enables us to directly image how polar cap patches are born in the cusp. In this paper, we present a few intervals of daytime optical observations, during which polar cap patches were generated within the field-of-view of an all-sky imager in Longyearbyen. During all the intervals studied here, we identified several signatures of poleward moving auroral forms (PMAF) in the equatorward half of the field-of-view, which are known as ionospheric manifestations of dayside reconnection. Interestingly, patches were directly produced from such poleward moving auroral signatures and propagated poleward along the anti-sunward convection near the cusp. In the literature, Lorentzen et al. (2012) first reported such a direct production of patches from PMAFs. During the current observations, however, we succeeded in tracking the propagation of patches until they reached the poleward edge of the field-of-view of the imager. This confirms that the faint airglow structures produced from PMAFs were actually transported for a long distance towards the central polar cap area; thus, polar cap patches were produced. From this set of observations, we suggest that polar cap patches during moderately disturbed conditions (i.e, non-storm time conditions) can be directly produced by the

  8. Formulation Optimization of Arecoline Patches

    PubMed Central

    Wu, Pao-Chu; Tsai, Pi-Ju; Lin, Shin-Chen; Huang, Yaw-Bin

    2014-01-01

    The response surface methodology (RSM) including polynomial equations has been used to design an optimal patch formulation with appropriate adhesion and flux. The patch formulations were composed of different polymers, including Eudragit RS 100 (ERS), Eudragit RL 100 (ERL) and polyvinylpyrrolidone K30 (PVP), plasticizers (PEG 400), and drug. In addition, using terpenes as enhancers could increase the flux of the drug. Menthol showed the highest enhancement effect on the flux of arecoline. PMID:24707220

  9. 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

  10. Development of a Teat Bio-sealant and Evaluation of its Technological and Functional Properties.

    PubMed

    Serna-Cock, Liliana; Pabón-Rodríguez, Omar Vladimir

    2016-06-01

    A teat bio-sealant was developed using Weissella cibaria, and the bio-sealant's technological and functional properties were assessed. The development included four experimental phases that were analyzed using independent experimental designs. Initially, sterilized or pasteurized Aloe vera gels were used, and the effect of heat treatment was investigated. In the second phase, the effects of time, storage temperature, and addition of cryopreservatives on the viability of the probiotic were observed. The third phase consisted of evaluating the synergistic effects of the cryopreservatives. The fourth phase involved selecting a material that would provide viscosity to the teat sealant. Technological and functional properties were measured in terms of viability of W. cibaria, and antimicrobial activity against Staphylococcus aureus and Streptococcus agalactiae was also analyzed. A mixture of milk powder and glycerol preserved this antimicrobial activity. Pullulan provided greater viscosity and maintained the technological and functional properties of the bio-sealant for 29 days. This teat bio-sealant can be used as an alternative for the prevention of bovine mastitis. PMID:27084703

  11. Evaluation after 4 years of the combined use of fluoride and dental sealants.

    PubMed

    Selwitz, R H; Nowjack-Raymer, R; Driscoll, W S; Li, S H

    1995-02-01

    This study evaluates the caries-preventive potential in permanent teeth of dental sealants when combined with an ongoing, school-based fluoride program. The investigation was designed as a sequential, cross-sectional comparison. Dental caries findings in 1987 for 416 children ages 7-11 and 14-17 who received dental sealants and fluorides were compared with corresponding data derived from 1983 baseline examinations of children who received fluoride therapy only. In addition, sealant retention status was determined. Overall mean DMFS scores in 1987 for children in two age groups combined were 51% lower than in 1983. Also, a surface-specific treatment effect was demonstrated in pit and fissures for both older and younger age groups. The overall proportion of sealants retained on occlusal surfaces of first molars after an average of 2 yr (92%) compared favorably with similar figures cited in the scientific literature. The results of this study suggest that pit and fissure sealants confer additional caries-preventive benefits beyond those of fluoride therapy alone. PMID:7774174

  12. A new resin technology: a glaze/composite sealant that cures without forming an oxygen-inhibited layer.

    PubMed

    Suh, Byoung I

    2003-08-01

    Until now, intraoral composite resin sealants cured with an oxygen-inhibited layer. In addition, resin glazes used for temporaries and processed appliances could not be used intraorally. This article describes the strategies behind the development of a new resin product that can be used intra- and extraorally as a sealant/glaze without forming an oxygen-inhibited layer after curing. PMID:14692216

  13. Demonstration of an instrumented patch

    NASA Astrophysics Data System (ADS)

    Martinez, M.; Renaud, G.; Backman, D.; Genest, M.; Delannoy, M.

    2007-04-01

    The primary objective of this study was to demonstrate the effectiveness of various strain measurement techniques at detecting the disbonding of a composite repair patch and then using this information to validate a new capacitance based disbond detection technique. The instrumented repair patch was parametrically designed with the help of Finite Element Analysis (FEA) software to have a stress concentration at its tip. This stress concentration was designed to produce a disbond during fatigue testing, without the need for the introduction of any foreign material to create an artificial disbond condition. The aluminum substrate was grit blasted and the instrumented patch was bonded using FM ®73 adhesive, and was cured following the recommendations of the manufacturer. The geometric characteristics of the patch followed standard repair guidelines for such variables as material selection, taper angles and loading conditions, with the exception of the area designed for premature disbond. All test specimens were inspected using non-destructive testing technique (ultrasound pulse echo) to guarantee that no disbonding had occurred during curing of the specimen. The specimens were placed under fatigue loading to induce a disbond condition between the aluminum substrate and the patch. The specimens were cyclically loaded and strain gauges bonded to strategic locations on the aluminum and composite patch surface to be able to measure changes in surface strains as the disbond progressed. A Digital Image Correlation (DIC) system was also used to measure full field strains over the gauge length of the coupon. The DIC results were compared with the strain gauge data and were used to provide a qualitative measure of the load transfer in the bonded specimen, which clearly demonstrated the change in surface strain that occurred as the composite patch disbonded from the aluminum substrate. Thermoelastic Stress Analysis (TSA) was also used to measure surface strains on the

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

    PubMed Central

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

    2015-01-01

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

  15. 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

    2015-01-01

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

  16. 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

  17. 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.

  18. The sealing performance of a self-sealing pipe flange connection with anaerobic sealants

    SciTech Connect

    Kobayashi, Takashi; Kumakura, Susumu

    1996-12-01

    Deteriorated sealing performance of pipe flange connections is attributable to separation of contacting surfaces between flanges due to high internal pressure or external bending load. In the previous paper, a design concept of a pipe flange connection having self-sealing performance was demonstrated and it was shown that the pipe flange connection has excellent sealing performance under combined loads of internal pressure and external bending moment. However, for simplicity, neither gaskets nor sealants were used in the experiments. For practical application of the self-sealing pipe flange connection, anaerobic sealants were used between the flanges and the sealing performance was tested in this study. Comparisons concerning sealing performance between the self-sealing flange connections and conventional flange connections were made. It is shown that the self-sealing flange connection with anaerobic sealants has the highest sealing performance under combined loads of internal pressure and external bending moment.

  19. The sealing performance of liquid sealant in flexible flanged bolted joints

    SciTech Connect

    Yoneno, Masahiro; Kawamura, Hiroshi; Sawa, Toshiyuki

    1996-12-01

    Recently, bolted joints with flexible flanges have been used from a lightweight viewpoint. However, it is difficult to improve the sealing performance of the joints due to the reduction of the interface pressure. In this paper, a liquid sealant is applied to a flexible flanged bolted joint in order to improve the sealing performance. In the experiments, a leakage is observed when flanged bolted joints sealed by gasket and liquid sealants with flange thickness of 1 and 6 mm are subjected to internal pressure. In addition, the effects of the adjacent bolt distance, the flange thickness and the bolt preload on the sealing performance are examined. Moreover, the interface stress distribution of flexible bolted flanged joints is analyzed using two-dimensional theory of elasticity and finite-element method to compare the experimental and numerical results. It is found that the sealing performance of bolted joints with liquid sealant is improved in comparison to that with the conventional gaskets.

  20. Periodicities of polar cap patches

    NASA Astrophysics Data System (ADS)

    Hosokawa, K.; Taguchi, S.; Ogawa, Y.; Aoki, T.

    2013-01-01

    A highly sensitive all-sky electron multiplier charge-coupled device airglow imager has been operative in Longyearbyen, Norway since October 2011. The imager captures 630.0 nm all-sky images with an exposure time of 4 s, which is about 10 times shorter than that achieved by conventional cooled CCD imagers. This allows us to visualize the structure of polar cap patches without blurring effects and better estimate their periodicities. We present, as one of the first results from the imager, an event of successive appearance of patches on the night of 21 December 2011. A time series of the optical intensity at zenith showed modulations having two distinguished periods, one at 40 min and the other at 5-12 min. One possible explanation is that such a coexistence of two different periodicities is a manifestation of simultaneous occurrence of patch generation processes on the 40 min periodicity was created by large-scale reconfiguration of the dayside convection pattern while the 5-12 min modulations were closely associated with mechanisms driven by pulsed reconnection on the dayside magnetopause. Such a combined effect of multiple patch generation processes may play a role in structuring patches; thus, it would be of particular importance for evaluating the space weather effects in the trans-ionospheric communications environment in the polar cap.

  1. A Chitosan-Based Sinus Sealant for Reduction of Adhesion Formation in Rabbit and Sheep Models

    PubMed Central

    Medina, Jennifer G.; Steinke, John W.; Das, Subinoy

    2013-01-01

    Objective Chronic sinusitis is the most prevalent chronic disease in the United States in adults aged 18 to 44 years, with approximately 250,000 operations performed annually. Although often successful, sinus surgery fails in greater than 15% of patients. Adhesion formation is a common complication and cause for subsequent revision surgery. Here, the authors evaluate a sprayable chitosan/starch-based sinus sealant and demonstrate its ability to reduce adhesion formation both in vitro and in 2 animal models. Study Design Randomized, controlled, animal trials. Setting Academic medical center (fibroblast experiments) and animal laboratories (sheep and rabbit studies). Subjects and Methods This sinus sealant was applied to human cultured fibroblasts obtained from surgically removed polyps to examine its ability to inhibit fibroblast migration and proliferation. The sinus sealant was applied to New Zealand White rabbits (n = 20) in an established cecal-sidewall abrasion model and to sheep (n = 10) in a sinus surgical adhesion model to examine its ability to reduce adhesion formation. Results This sinus sealant inhibited migration and proliferation of human cultured fibroblasts and reduced the total adhesion score from 4.9 to 0.3 for a total reduction of 94% (95th percentile confidence interval [CI], 78%, 100%; P < .001) in a well-established rabbit cecal-sidewall model commonly used for adhesion testing. Moreover, this sealant reduced adhesion formation from 80% to 10% for a total reduction of 70% (95th percentile CI, 57%, 93%; P = .003) in a sheep sinus adhesion surgical model. Conclusion This chitosan-based sealant demonstrates promise for reducing adhesion formation in sinus surgery. PMID:22492298

  2. Ability of Pit and Fissure Sealant-containing Amorphous Calcium Phosphate to inhibit Enamel Demineralization

    PubMed Central

    Owais, Arwa I; Kawaja, Wasan

    2016-01-01

    ABSTRACT Aim: To evaluate the effect of amorphous calcium phosphate (ACP)-containing pit and fissure sealant on inhibition of enamel demineralization in vitro. Materials and methods: Enamel specimens (n = 75) were prepared using freshly extracted noncarious human third molars. Box-shaped cavities (8 × 2 × 2 mm) on the buccal or lingual surfaces were prepared and restored with resin-based sealant (Concise™), ACP-containing sealant (Aegis®) or fluoride-containing sealant (Conseal-F™). The samples were acid challenged in a demineralizing solution of 50 mmol/l lactic acid at pH 5.0 for 4 days. The change in enamel microhardness (ASuH) was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test. Results: The mean SuH0 (±SD) (in Vicker’s unit) prior to the acid challenge was: Concise™ (318.83 ± 33.86), Aegis® (331.03 ± 21.52), Conseal-F™ (310.12 ± 34.31). Following the acid challenge, the values dropped in all groups and ASuH (±SD) values were 269.17 ± 47.49, 151.39 ± 23.96 and 175.79 ± 32.39 respectively. Conclusion: The ACP-containing pit and fissure sealant has the potential to inhibit enamel demineralization. How to cite this article: Zawaideh FI, Owais AI, Kawaja W. Ability of pit and fissure sealant-containing amorphous calcium phosphate to inhibit enamel demineralization. Int J Clin Pediatr Dent 2016;9(1):10-14. PMID:27274148

  3. 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

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

    SciTech Connect

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

    2013-02-19

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

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

    PubMed Central

    Yakovlev, Sergiy; Medved, Leonid

    2016-01-01

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

  6. 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

  7. 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

  8. Obstructive fibrinous tracheal pseudomembrane: a rare condition in postextubation stridor.

    PubMed

    Nakwan, Narongwit

    2014-07-01

    Obstructive fibrinous tracheal pseudomembrane (OFTP) is an airway complication that occurs after endotracheal intubation. It originates from superficial mucosal abrasion and desquamation of necrotic tracheal epithelium at the site of cuff pressure. This condition is a rare cause of postextubation stridor. We present a case of postextubation stridor secondary to OFTP, resulting in clinical features of upper airway obstruction > 8 h after extubation. The case features complete obstruction at the tip of the endotracheal tube from OFTP. PMID:24170917

  9. 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

    2016-03-01

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

  10. Dialysis catheter fibrin sheath stripping: a useful technique after failed catheter exchange.

    PubMed

    Mohamad Ali, Af; Uhwut, E; Liew, Sk

    2012-01-01

    Fibrin sheath formation around long-term haemodialysis catheter is a common cause of failed dialysis access. Treatment options include pharmacological and mechanical methods. This paper reports a case of failed dialysis access due to fibrin sheath encasement. Pharmacologic thrombolysis, mechanical disruption using guide wire and catheter exchange had failed to address the issue. Eventually, fibrin sheath stripping using the loop snare technique was able to successfully restore the catheter function. PMID:22970064

  11. Caries-preventive Effect of Supervised Toothbrushing and Sealants.

    PubMed

    Hilgert, L A; Leal, S C; Mulder, J; Creugers, N H J; Frencken, J E

    2015-09-01

    To investigate the effectiveness of 3 caries-preventive measures on high- and low-caries risk occlusal surfaces of first permanent molars over 3 y. This cluster-randomized controlled clinical trial covered 242 schoolchildren, 6 to 7 y old, from low socioeconomic areas. At baseline, caries risk was assessed at the tooth surface level, through a combination of ICDAS II (International Caries Detection and Assessment System) and fissure depth codes. High-caries risk occlusal surfaces were treated according to daily supervised toothbrushing (STB) at school and 2 sealants: composite resin (CR) and atraumatic restorative treatment-high-viscosity glass-ionomer cement (ART-GIC). Low-caries risk occlusal surfaces received STB or no intervention. Evaluations were performed after 0.5, 1, 2, and 3 y. A cavitated dentine carious lesion was considered a failure. Data were analyzed according to the proportional hazard rate regression model with frailty correction, Wald test, analysis of variance, and t test, according to the jackknife procedure for calculating standard errors. The cumulative survival rates of cavitated dentine carious lesion-free, high-caries risk occlusal surfaces were 95.6%, 91.4%, and 90.2% for STB, CR, and ART-GIC, respectively, over 3 y, which were not statistically significantly different. For low-caries risk occlusal surfaces, no statistically significant difference was observed between the cumulative survival rate of the STB group (94.8%) and the no-intervention group (92.1%) over 3 y. There was neither a difference among STB, CR, and ART-GIC on school premises in preventing cavitated dentine carious lesions in high-caries risk occlusal surfaces of first permanent molars nor a difference between STB and no intervention for low-caries risk occlusal surfaces of first permanent molars over 3 y. PMID:26116491

  12. Physical Determinants of Fibrinolysis in Single Fibrin Fibers

    PubMed Central

    Bucay, Igal; O’Brien, E. Tim; Wulfe, Steven D.; Superfine, Richard; Wolberg, Alisa S.; Falvo, Michael R.; Hudson, Nathan E.

    2015-01-01

    Fibrin fibers form the structural backbone of blood clots; fibrinolysis is the process in which plasmin digests fibrin fibers, effectively regulating the size and duration of a clot. To understand blood clot dissolution, the influence of clot structure and fiber properties must be separated from the effects of enzyme kinetics and perfusion rates into clots. Using an inverted optical microscope and fluorescently-labeled fibers suspended between micropatterned ridges, we have directly measured the lysis of individual fibrin fibers. We found that during lysis 64 ± 6% of fibers were transected at one point, but 29 ± 3% of fibers increase in length rather than dissolving or being transected. Thrombin and plasmin dose-response experiments showed that the elongation behavior was independent of plasmin concentration, but was instead dependent on the concentration of thrombin used during fiber polymerization, which correlated inversely with fiber diameter. Thinner fibers were more likely to lyse, while fibers greater than 200 ± 30 nm in diameter were more likely to elongate. Because lysis rates were greatly reduced in elongated fibers, we hypothesize that plasmin activity depends on fiber strain. Using polymer physics- and continuum mechanics-based mathematical models, we show that fibers polymerize in a strained state and that thicker fibers lose their prestrain more rapidly than thinner fibers during lysis, which may explain why thick fibers elongate and thin fibers lyse. These results highlight how subtle differences in the diameter and prestrain of fibers could lead to dramatically different lytic susceptibilities. PMID:25714359

  13. 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)....

  14. 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)....

  15. 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)....

  16. Comparison of the fibrin-binding activities in the N- and C-termini of fibronectin.

    PubMed Central

    Rostagno, A A; Schwarzbauer, J E; Gold, L I

    1999-01-01

    Fibronectin (Fn) binds to fibrin in clots by covalent and non-covalent interactions. The N- and C-termini of Fn each contain one non-covalent fibrin-binding site, which are composed of type 1 (F1) structural repeats. We have previously localized the N-terminal site to the fourth and fifth F1 repeats (4F1.5F1). In the current studies, using proteolytic and recombinant proteins representing both the N- and C-terminal fibrin-binding regions, we localized and characterized the C-terminal fibrin-binding site, compared the relative fibrin-binding activities of both sites and determined the contribution of each site to the fibrin-binding activity of intact Fn. By fibrin-affinity chromatography, a protein composed of the 10F1 repeat through to the C-terminus of Fn (10F1-COOH), expressed in COS-1 cells, and 10F1-12F1, produced in Saccharomyces cerevisiae, displayed fibrin-binding activity. However, since 10F1 and 10F1.11F1 were not active, the presence of 12F1 is required for fibrin binding. A proteolytic fragment of 14.4 kDa, beginning 14 residues N-terminal to 10F1, was isolated from the fibrin-affinity matrix. Radio-iodinated 14.4 kDa fibrin-binding peptide/protein (FBP) demonstrated a dose-dependent and saturable binding to fibrin-coated wells that was both competitively inhibited and reversed by unlabelled 14.4 kDa FBP. Comparison of the fibrin-binding affinities of proteolytic FBPs from the N-terminus (25.9 kDa FBP), the C-terminus (14.4 kDa) and intact Fn by ELISA yielded estimated Kd values of 216, 18 and 2.1 nM, respectively. The higher fibrin-binding affinity of the N-terminus was substantiated by the ability of both a recombinant 4F1.5F1 and a monoclonal antibody (mAb) to this site to maximally inhibit biotinylated Fn binding to fibrin by 80%, and by blocking the 90% inhibitory activity of a polyclonal anti-Fn, by absorption with the 25.9 kDa FBP. We propose that whereas the N-terminal site appears to contribute to most of the binding activity of native Fn to

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2016-01-01

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

  19. Immunohistological assessment of fibrin deposition and thrombus formation in canine mammary neoplasia.

    PubMed

    Golombiewski, A; Gutberlet, K; Rudolph, R

    1997-08-01

    A commercially available monoclonal antibody against human fibrin was used to detect fibrin in canine formalin-fixed, paraffin wax-embedded tissue by applying a slightly modified alkaline phosphatase anti-alkaline phosphatase (APAAP) technique. Twenty-eight mammary tumours from six bitches were examined for the presence of fibrin. Thrombi and extravascular fibrin deposits were detected in 15 tumours (12 complex adenocarcinomas, one adenocarcinoma, two solid carcinomas), and a single thrombus was detected in one adenoma; 12 tumours (three adenomas, one complex adenoma, four complex adenocarcinomas and four adenocarcinomas) did not show any staining reaction. PMID:9352443

  20. 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

  1. The conversion of fibrinogen to fibrin. XIII. Dissolution of fibrin and inhibition of clotting by various neutral salts.

    PubMed

    SHULMAN, S; KATZ, S; FERRY, J D

    1953-07-01

    1. Fibrin clots prepared in the absence of calcium can be dissolved in solutions of lithium chloride and bromide and sodium bromide and iodide, as well as of guanidine hydrochloride and urea. These salts do not denature fibrinogen under the same conditions of concentration, temperature, and time. Sedimentation experiments on the fibrin solutions show in each case a single sharp peak with a sedimentation constant close to that of fibrinogen. 2. At lower concentrations, these salts inhibit the clotting of fibrinogen by thrombin, but in the case of lithium bromide and sodium iodide, at least, allow an intermediate polymer to accumulate whose sedimentation constant is close to that of the polymer observed in systems inhibited by hexamethylene glycol or urea. PMID:13069679

  2. A 48-month randomized controlled trial of caries prevention effect of a one-time application of glass ionomer sealant versus resin sealant.

    PubMed

    Haznedaroğlu, Eda; Güner, Şirin; Duman, Canan; Menteş, Ali

    2016-06-01

    The aim of this study was to compare the caries prevention effectiveness, retention rates and the level of fluoride of saliva of a glassionomer sealant (GIS) with that of a resin-based sealant (RS). Eighty GIS and 80RS were placed on the first permanent molars in 40 children aged 7-10 years. Children were re-examined at 6, 12, 24, 36 and 48 months after the procedure. Saliva samples were collected before the sealant was applied and again at each appointment, and fluoride levels were measured. After 48 months, occlusal caries were seen in 4 and 12 teeth in GIS and RS groups respectively. There was a statistically significant difference in the fluoride levels of saliva between baseline and up to 12th month in GIS group. GISs presented effective prevention of caries development, even though the failure rate is higher when compared to the RSs. An increased salivary fluoride level due to GISs might be an additive effect on the prevention of dental caries. PMID:27086573

  3. 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.

  4. Smart patch piezoceramic actuator issues

    NASA Astrophysics Data System (ADS)

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

    1993-02-01

    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.

  5. 76 FR 79537 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Adhesives and Sealants Rule

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-22

    ...EPA is approving a State Implementation Plan (SIP) revision submitted by the State of Delaware. The revision adds section 4.0, under Regulation 1141, relating to the control of emissions of volatile organic compounds (VOC) from the manufacture, sale, use, or application of adhesives, sealants, primers, and solvents. EPA is approving this SIP revision to meet the requirements of a reasonably......

  6. 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...

  7. INVESTIGATION OF THE POTENTIAL ANTIMICROBIAL EFFICACY OF SEALANTS USED IN HVAC SYSTEMS: JOURNAL ARTICLE

    EPA Science Inventory

    NRMRL-RTP-P- 530a Foarde, K.K., VanOsdell, D.W., and Menetrez*, M.Y. Investigation of the Potential Antimicrobial Efficacy of Sealants Used in HVAC Systems. Published in: Journal of Air and Waste Management Association 51 (8):1219-1226 (2001). 07/06/2000 The paper gives result...

  8. 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

  9. 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...

  10. Mechanical properties and failure analysis of visible light crosslinked alginate-based tissue sealants.

    PubMed

    Charron, Patrick N; Fenn, Spencer L; Poniz, Alex; Oldinski, Rachael A

    2016-06-01

    Moderate to weak mechanical properties limit the use of naturally-derived tissue sealants for dynamic medical applications, e.g., sealing a lung leak. To overcome these limitations, we developed visible-light crosslinked alginate-based hydrogels, as either non-adhesive methacrylated alginate (Alg-MA) hydrogel controls, or oxidized Alg-MA (Alg-MA-Ox) tissue adhesive tissue sealants, which form covalent bonds with extracellular matrix (ECM) proteins. Our study investigated the potential for visible-light crosslinked Alg-MA-Ox hydrogels to serve as effective surgical tissue sealants for dynamic in vivo systems. The Alg-MA-Ox hydrogels were designed to be an injectable system, curable in situ. Burst pressure experiments were conducted on a custom-fabricated burst pressure device using constant air flow; burst pressure properties and adhesion characteristics correlated with the degrees of methacrylation and oxidation. In summary, visible light crosslinked Alg-MA-Ox hydrogel tissue sealants form effective seals over critically-sized defects, and maintain pressures up to 50mm Hg. PMID:26897093

  11. 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. PMID:16297312

  12. 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... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Emission Limits for Puncture Sealant... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

  13. 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... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Emission Limits for Puncture Sealant... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. In Vitro Comparison of Microleakage of Two Materials Used as Pit and Fissure Sealants

    PubMed Central

    Bahrololoomi, Zahra; Soleymani, Aliasghar; Heydari, Zahra

    2011-01-01

    Background and aims Marginal seal of the material is extremely important in fissure sealant therapy. The aim of this study was to investigate microleakage of flowable composite resins and conventional fissure sealants with or without dentin bonding agent. Materials and methods The occlusal surface of 60 intact extracted human premolars, divided into four groups, were cleaned with pumice/slurry, etched with 37% phosphoric acid for 15 seconds, rinsed and dried. Groups were treated differ-ently: Excite bonding agent followed by Helioseal F fissure sealant in group1; Helioseal F alone in group 2; Excite bonding agent followed by Tetric Flow in group 3; and Tetric Flow alone in group 4. Light-curing was done after each application. After thermocycling, the whole surface of each specimen was coated with nail varnish except for one millimeter around the fissure sealant. The teeth were immersed in 2% basic fuchsin for 24 hours and then sectioned buccolingually. The sections were analyzed for leakage under a stereomicroscope. Data was analyzed by Kruskal-Wallis and Mann-Whitney tests at asignificance level of P < 0.05. Results There were no statistically significant differencesbetween the study groups in terms of the mean microleakage scores (P > 0.05), except for groups 2 and 4 (P = 0.002) and groups 3 and 4 (P = 0.033). Conclusion Use of a flowable composite with bonding agent is a good alternative for sealing pits and fissures; however, further in vitro and in vivo studies are necessary. PMID:22991611

  19. 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...

  20. Increased fibrin formation and impaired fibrinolytic capacity in severe chronic kidney disease.

    PubMed

    Mörtberg, Josefin; Blombäck, Margareta; Wallén, Åkan; He, Shu; Jacobson, Stefan H; Spaak, Jonas

    2016-06-01

    Chronic kidney disease (CKD) is associated with a concurrent increased risk of thrombosis and bleeding. We aimed to investigate whether CKD is associated with increased fibrin formation, impaired fibrin degradation, or both. Twenty-one patients with CKD stage 4 (CKD 4), 15 haemodialysis patients, and 13 controls (C) without kidney disease were studied. We used a global assay to determine fibrin formation and degradation in plasma. Fibrin turbidity was measured over time to obtain a value of the coagulation activation profile (Cp) and the fibrinolysis activation profile (Fp), and the amount of fibrin formed, termed fibrin optical density sum (fibrin OD-sum). We used scanning electron microscopy (SEM) to visualize the fibrin network. Plasminogen activator inhibitor type-1 antigen, thrombin-activatable fibrinolysis inhibitor activity, fibrinogen, von Willebrand factor, antithrombin, albumin, and C-reactive protein were measured in plasma. Fibrin OD-sum was significantly elevated in haemodialysis patients [312 a.u.; 278-435 (median; interquartile range); P < 0.0013] and in CKD 4 (293 a.u.; 169-434; P = 0.0119) compared with controls (115 a.u.; 82-234). SEM showed a tight fibrin network in haemodialysis and CKD 4 patients. Fp was lower in the haemodialysis group than in controls (P = 0.030). Plasminogen activator inhibitor type-1 was lower in haemodialysis patients (P = 0.034). Thrombin-activatable fibrinolysis inhibitor activity, Cp, antithrombin, and C-reactive protein did not differ between groups. Fibrinogen was significantly elevated and albumin decreased in both haemodialysis and CKD 4 patients compared with controls. Von Willebrand factor was elevated in haemodialysis patients compared with controls (P = 0.010). The prothrombotic state in severe CKD is characterized by impaired fibrinolysis in association with increased fibrin formation despite normal levels of endogenous fibrinolysis inhibitors. PMID:26650459

  1. Prevalence of Dental Caries and Fissure Sealants in a Portuguese Sample of Adolescents

    PubMed Central

    Veiga, Nélio J.; Pereira, Carlos M.; Ferreira, Paula C.; Correia, Ilidio J.

    2015-01-01

    Introduction The aims of this study were to assess the prevalence of dental caries and the DMFT index, as well as the distribution pattern of pit and fissure sealants on permanent teeth in a Portuguese sample of adolescents, and to assess whether the existing usage of sealants and socio-demographic factors are correlated to caries prevalence on the examined sample. Materials and Methods A cross-sectional study was designed with a sample of 447 adolescents aged 12 to 18 years old, attending a public school in Sátão, Portugal. A self-administered questionnaire with questions about oral health behaviours and socio-economic status was answered by adolescents in the classroom. Clinical examination of oral health status and assessment of fissure sealants were accomplished by only one trained member of the research team. Results We obtained a DMFT index of 3.32 (2.92), which indicates a moderate level of prevalence of dental caries. When considering a DMFT = 0, we found significant statistical differences between the parents´ level of education (≤ 4th grade = 26.3 vs 5th–12th grade = 18.8 vs <12th grade = 43.3, p = 0.001), gender (male = 27.3 vs female = 19.6, p = 0.04), age (≤15 years = 27.1 vs <15 years = 18.5, p = 0.02), presence of fissure sealants (yes = 30.6 vs no = 13.5, p = 0.001) and experience of dental pain (no = 25.4 vs yes = 16.8, p = 0.02). When analyzing the prevalence of fissure sealants, we verified that 58.8% of adolescents had at least one fissure sealant applied. Significant statistical differences were found when analyzing the presence of fissure sealants related with parents´educational level (<9th grade, OR = 1.56 CI95% = 1.05–2.54), gender (female, OR = 1.86 CI95% = 1.19–2.98), experience of dental pain (yes, OR = 0.62 CI95% = 0.39–0.97) and presence of dental caries (yes, OR = 0.35 CI95% = 0.19–0.65). Conclusions The moderate level of caries prevalence reveals the need of improvement of primary prevention interventions among

  2. Children, sealants, and guardians who smoke: Trends in NHANES 2001-2002 to 2010-2012

    PubMed Central

    Wiener, R. Constance

    2015-01-01

    Objective There are many factors influencing dental behavior. The relationship of smokers who smoked inside the home toward preventive care (measured as dental sealant placement) of the children living in their homes is examined in this study. Methods Data from the National Health and Nutrition Examination Surveys in 2001-2002 and in 2011-2012 were analyzed. Data included variables to someone smoking inside the home, dental sealant placement in children ages 6-less than 20 years, and sociodemographics which were obtained from a dental examination and a home interview. Results There were 3,352 eligible participants in 2001-2002 and 2,374 in 2011-2012. The unadjusted odds ratio for not having dental sealants when there was someone who smoked inside the home as compared with not having dental sealants when there was no one who smoked inside the home was 1.57 (95%CI: 1.17, 2.10) in 2001-2002. The unadjusted odds ratio was 1.56 (95% CI: 1.20, 2.03) in 2011-2012. When the data were adjusted for age, sex, race/ethnicity, insurance, and income to poverty ratio, the 2001-2002 adjusted odds ratio was 1.31 (95%CI: 0.97, 1.78). The adjusted odds ratio in 2011-2012 was 1.41 (95% CI:1.01, 1.95). Conclusions Children who lived in homes in which someone smoked inside the home were more likely to not have dental sealants compared with children who lived in homes in which no one smoked inside the home. These results are important for understanding the factors related to access to dental care issues for children. PMID:26213630

  3. 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. PMID:24372898

  4. 21 CFR 864.7320 - Fibrinogen/fibrin degradation products assay.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Fibrinogen/fibrin degradation products assay. 864.7320 Section 864.7320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7320 Fibrinogen/fibrin degradation...

  5. 21 CFR 864.7320 - Fibrinogen/fibrin degradation products assay.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Fibrinogen/fibrin degradation products assay. 864.7320 Section 864.7320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7320 Fibrinogen/fibrin degradation...

  6. Modification of fibrin network ultrastructure by Fab fragments specific for different domain of fibrinogen.

    PubMed

    Cierniewski, C S; Janiak, A; Wyroba, E

    1986-01-01

    Kinetics of inhibition of fibrin monomer polymerization produced by Fab fragments prepared from immunochemically purified monospecific antibodies to the surface epitopes of different domains of fibrinogen molecule has been correlated with electron microscopic observations of resulting specimens. Fab fragments prepared from anti FgD antisera were the most efficient inhibitors of thrombin-catalysed conversion of fibrinogen to fibrin; polymerization of fibrin monomers as detected spectrophotometrically was abolished at 2:1 molar ratio of anti FgD Fab fragments to fibra monomer. These Fab fragments acting as a steric hindrance of polymerization sites inhibited the first stage of fibrin monomer aggregation. Interaction of Fab fragments derived from antibodies specific for alpha 239-476 with corresponding segment of fibrinogen molecule resulted in a weak inhibition of fibrin monomer polymerization. However, fibrin obtained in the presence of these Fab fragments was significantly modified and showed no periodicity. This observation may suggest that anti alpha 239-476 Fab impaired the course of the second stage of fibrin monomer polymerization, i.e. lateral association of fibrin fibrils. PMID:2433859

  7. Simultaneous measurement of thrombin generation and fibrin formation in whole blood under flow conditions.

    PubMed

    Kelchtermans, Hilde; Pelkmans, Leonie; Bouwhuis, Anne; Schurgers, Evelien; Lindhout, Theo; Huskens, Dana; Miszta, Adam; Hemker, H Coenraad; Lancé, Marcus D; de Laat, Bas

    2016-07-01

    Assays based on the formation of thrombin and fibrin are frequently used, and results are considered exchangeable in research/clinical settings. However, thrombin generation and fibrin formation do not always go hand in hand and flow profoundly influences thrombus formation. We describe the technical/clinical evaluation of an assay to simultaneously measure thrombin generation and fibrin formation under conditions of flow. Introduction of a fluorometer into a 'cone and base principle'-based rheometer allowed the measurement of thrombin generation (using a thrombin-sensitive substrate) and fibrin formation (changes in viscosity), while applying a linear shear flow. Increasing shear rates inversely related with thrombin generation and fibrin formation. Increasing fibrinogen concentrations in defibrinated plasma resulted in increased thrombin generation and fibrin formation. In pre-operative samples of 70 patients undergoing cardiothoracic surgery, fibrin formation and thrombin generation parameters correlated with fibrinogen content, rotational thromboelastometry (ROTEM) and whole blood Calibrated Automated Thrombinography (CAT) parameters, respectively. Upon dividing patients into two groups based on the median clot strength, a significant difference in perioperative/total blood loss was established. In conclusion, we clinically evaluated a method capable of simultaneously measuring thrombin generation and fibrin formation in plasma/whole blood under continuous flow, rendering our method one step closer to physiology. Importantly, our test proved to be indicative for the amount of blood loss during/after cardiothoracic surgery. PMID:27074907

  8. Role of fibrinopeptide B release: comparison of fibrins produced by thrombin and Ancrod.

    PubMed

    Shen, L L; Hermans, J; McDonagh, J; McDonagh, R P

    1977-06-01

    The gelation time, opacity, light scattering, and elastic moduli of human fibrin gels clotted in the presence of thrombin, Ancrod, and Reptilase have been compared. At low ionic strength lateral association to thick fibers is observed in all cases. At all ionic strengths thrombin fibrin forms thicker fibers than does Ancrod fibrin. We have demonstrated that an increase in the extent of lateral association is linked to an increase in its velocity and to a decrease in the gelation time. One may consider the removal of fibrinopeptide B to act as a switch: after it is removed fibrin assembles rapidly to thick fibers and gelation is fast; but when this peptide is still attached, there is a slow assembly of thin fibers, and gelation, especially of dilute fibrin, is delayed. We believe that this delay is critical for the complete digestion by plasmin of fibrin formed during in vivo defibrination with Ancrod and of fibrin produced by very small amounts of thrombin (which would still contain fibrinopeptide B), and that slow release of fibrinopeptide B is part of a control mechanism for the regulation of fibrin formation and the prevention of intravascular coagulation. PMID:879301

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

    PubMed Central

    Lucas, Matthias; Seeber, Petra

    2015-01-01

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

  10. Aprotinin extends mechanical integrity time of cell-seeded fibrin sutures.

    PubMed

    Coffin, Spencer T; Gaudette, Glenn R

    2016-09-01

    Cell therapy has the potential to treat different pathologies, including myocardial infarctions (heart attacks), although cell engraftment remains elusive with most delivery methods. Biological sutures composed of fibrin have been shown to effectively deliver human mesenchymal stem cell (MSC) to infarcted hearts. However, human MSCs rapidly degrade fibrin making cell seeding and delivery time sensitive. To delay the degradation process, we propose using Aprotinin, a proteolytic enzyme inhibitor that has been shown to slow fibrinolysis. Human MSCs seeded on fibrin sutures and incubated with Aprotinin demonstrated similar cell viability, examined using a LIVE/DEAD stain, to controls. No differences in proliferation, as determined by Ki-67 presence, were observed. Human MSCs incubated in Aprotinin differentiated into adipocytes, osteocytes, and chondrocytes, confirming multipotency. The number of cells adhered to fibrin sutures increased through Aprotinin supplementation at 2, 3, and 5 day time points. Uniaxial tensile testing was used to examine the effect of Aprotinin on suture integrity. Sutures exposed to Aprotinin had higher ultimate tensile strength and modulus when compared to sutures exposed to standard growth media. Fibrin sutures incubated in Aprotinin had larger diameters and less fibrin degradation products compared to the controls, confirming decreased fibrinolysis. These data suggest that Aprotinin can reduce degradation of fibrin sutures without significant effects on MSC function, providing a novel method for extending the implantation window and increasing the number of cells delivered via fibrin sutures. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2271-2279, 2016. PMID:27101153

  11. Warning: fatal reaction to the use of fibrin glue in deep hepatic wounds. Case reports.

    PubMed

    Berguer, R; Staerkel, R L; Moore, E E; Moore, F A; Galloway, W B; Mockus, M B

    1991-03-01

    Two cases of severe hypotension following the use of fibrin glue for hemostasis in hepatic injuries are reported. A systemic reaction to bovine thrombin via large venous lacerations is suspected. A preliminary animal study supports this hypothesis. Caution is advised in the use of fibrin glue for hemostasis in deep hepatic wounds. PMID:2002531

  12. 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.

  13. 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

  14. The presence of γ’ chain impairs fibrin polymerization

    PubMed Central

    Gersh, Kathryn C.; Nagaswami, Chandrasekaran; Weisel, John W.; Lord, Susan T.

    2009-01-01

    Introduction A fraction of fibrinogen molecules contain an alternatively spliced variant chain called γ’. Plasma levels of this variant have been associated with both myocardial infarction and venous thrombosis. Because clot structure has been associated with cardiovascular risk, we examined the effect of γ’ chain on clot structure. Materials and Methods We expressed three fibrinogen variants in Chinese hamster ovary (CHO) cells: γ/γ homodimer, γ/γ’ heterodimer, and γ’/γ’ homodimer. We observed thrombin-catalyzed fibrinopeptide release by HPLC, fibrin polymerization by turbidity, and clot structure by scanning electron microscopy. We characterized post-translational modifications by mass spectrometry. Results Fibrinopeptide A was released at the same rate for all three fibrinogens, while fibrinopeptide B was released faster from the γ’/γ’ homodimer. The rise in turbidity was slower and final absorbance was lower during polymerization of γ’-containing fibrinogens than for γ/γ fibrinogen. Micrographs showed that γ’/γ’ fibrin clots are composed of very thin fibers, while the diameter of γ/γ’ fibers is similar to γ/γ fibers. Further, the fiber networks formed from γ’-containing samples were non-uniform. Mass spectrometry showed heterogeneous addition of N-glycans and tyrosine sulfation in the γ’ chain. Conclusions The presence of γ’ chains slows lateral aggregation and alters fibrin structure. We suggest these changes are likely due to charge-charge repulsion, such that polymerization of the γ’/γ’ homodimer is more impaired than the heterodimer since these repulsions are partially offset by incorporation of γ chains in the γ/γ’ heterodimer. PMID:19138790

  15. OpenSSO Project Patches

    Energy Science and Technology Software Center (ESTSC)

    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.

  16. 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

  17. 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.

  18. Fibrinous anterior uveitis following laser in situ keratomileusis.

    PubMed

    Parmar, Pragya; Salman, Amjad; Rajmohan, M; Jesudasan, Nelson C A

    2009-01-01

    A 29-year-old woman who underwent laser in situ keratomileusis (LASIK) for myopic astigmatism in both eyes presented with severe pain, photophobia and decreased visual acuity in the left eye eight days after surgery. Examination revealed severe anterior uveitis with fibrinous exudates in the anterior chamber, flap edema and epithelial bullae. Laboratory investigations for uveitis were negative and the patient required systemic and intensive topical steroids with cycloplegics to control the inflammation. This case demonstrates that severe anterior uveitis may develop after LASIK and needs prompt and vigorous management for resolution. PMID:19574707

  19. 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

  20. 40 CFR Table 13 to Subpart Xxxx of... - Minimum Data for Continuous Compliance With the Emission Limitations for Puncture Sealant...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., option 2 a. A record of Method 311 (40 CFR part 63, appendix A), or approved alternative method, test... other type of control device to which puncture sealant application spray booth HAP emissions are...

  1. 40 CFR Table 13 to Subpart Xxxx of... - Minimum Data for Continuous Compliance With the Emission Limitations for Puncture Sealant...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of Method 311 (40 CFR part 63, appendix A), or approved alternative method, test results, indicating... of control device to which puncture sealant application spray booth HAP emissions are ducted so...

  2. Salmon fibrin treatment of spinal cord injury promotes functional recovery and density of serotonergic innervation.

    PubMed

    Sharp, Kelli G; Dickson, Amanda R; Marchenko, Steve A; Yee, Kelly M; Emery, Pauline N; Laidmåe, Ivo; Uibo, Raivo; Sawyer, Evelyn S; Steward, Oswald; Flanagan, Lisa A

    2012-05-01

    The neural degeneration caused by spinal cord injury leaves a cavity at the injury site that greatly inhibits repair. One approach to promoting repair is to fill the cavity with a scaffold to limit further damage and encourage regrowth. Injectable materials are advantageous scaffolds because they can be placed as a liquid in the lesion site then form a solid in vivo that precisely matches the contours of the lesion. Fibrin is one type of injectable scaffold, but risk of infection from blood borne pathogens has limited its use. We investigated the potential utility of salmon fibrin as an injectable scaffold to treat spinal cord injury since it lacks mammalian infectious agents and encourages greater neuronal extension in vitro than mammalian fibrin or Matrigel®, another injectable material. Female rats received a T9 dorsal hemisection injury and were treated with either salmon or human fibrin at the time of injury while a third group served as untreated controls. Locomotor function was assessed using the BBB scale, bladder function was analyzed by measuring residual urine, and sensory responses were tested by mechanical stimulation (von Frey hairs). Histological analyses quantified the glial scar, lesion volume, and serotonergic fiber density. Rats that received salmon fibrin exhibited significantly improved recovery of both locomotor and bladder function and a greater density of serotonergic innervation caudal to the lesion site without exacerbation of pain. Rats treated with salmon fibrin also exhibited less autophagia than those treated with human fibrin, potentially pointing to amelioration of sensory dysfunction. Glial scar formation and lesion size did not differ significantly among groups. The pattern and timing of salmon fibrin's effects suggest that it acts on neuronal populations but not by stimulating long tract regeneration. Salmon fibrin clearly has properties distinct from those of mammalian fibrin and is a beneficial injectable scaffold for treatment

  3. Bond Strength of a Bisphenol-A-Free Fissure Sealant With and Without Adhesive Layer under Conditions of Saliva Contamination.

    PubMed

    Mesquita-Guimarães, Késsia Suênia Fidelis de; Sabbatini, Iliana Ferraz; Almeida, Cintia Guimarães de; Galo, Rodrigo; Nelson-Filho, Paulo; Borsatto, Maria Cristina

    2016-01-01

    Dental sealants are important for prevention of carious lesions, if they have good shear strength. The aim of this study was to evaluate the shear bond strength (SBS) of two sealants to saliva-contaminated and non-contaminated enamel with and without an intermediate adhesive layer underneath the sealant. Ninety flat enamel surfaces from human third molars were randomly assigned to 6 groups (n=15): F (control): Fluroshield(tm) sealant; EWB (control): Embrace(tm) WetBond(tm); SB/F: Single Bond adhesive system + F; SB/EWB, s-SB/F and s-SB/EWB. In the s-SB/F and s-SB/EWB groups, the acid-etched enamel was contaminated with 0.01 mL of fresh human saliva for 20 s. Sealant cylinders were bonded to enamel surface with and without an intermediate adhesive system layer. The shear tests were performed using a universal testing machine (0.5 mm/min). Data were analyzed statistically by Kruskal-Wallis and Mann-Whitney tests (α=0.05). F presented higher mean SBS than EWB in all experimental conditions. The lowest SBS mean was obtained for EWB on contaminated enamel (p<0.05). In conclusion, an adhesive system layer should be used prior to sealant placement, in both dry and saliva-contaminated enamel. F had the best performance in all experimental conditions. EWB sealant showed very low results, but an adhesive layer underneath the sealant increased its SBS even after salivary contamination. PMID:27224565

  4. Use of occlusal sealant in a community program and caries incidence in high- and low-risk children

    PubMed Central

    BALDINI, Vânia; TAGLIAFERRO, Elaine Pereira da Silva; AMBROSANO, Gláucia Maria Bovi; MENEGHIM, Marcelo de Castro; PEREIRA, Antonio Carlos

    2011-01-01

    Objective The aims of this study were to investigate the effectiveness of sealant placement under the guidelines of the Oral Health Promotion Program for Children and Adolescents (Portugal), and to test the influence of clinical and socioeconomic variables on the DMFT increment in 277 children, born in 1997. Material and Methods A dental hygienist performed the initial examinations and sealant placement (Helioseal, Vivadent) on the permanent first molars in 2005. These activities were registered in dental records that were assessed in 2007. Children were classified according to caries risk at baseline [high (HR: DMFT+dmft>0); low (LR: DMFT+dmft=0) risk] and sealant placement as follows: HR-S and LR-S Groups (with sealant placement); HR-NS and LR-NS Groups (without sealant placement). A calibrated dentist performed the final examination in 2007 at school, based on the World Health Organization recommendations. The variables collected were: dental caries, visible dental plaque, malocclusions, and socioeconomic level (questionnaire sent to children's parents). For univariate (Chi-square or Fisher tests) and multivariate (Multiple logistic regression) analyses the DMFT increment >0 was selected as dependent variable. Results Approximately 17.0% of the children showed DMFT increment>0 (mean=0.25). High-risk children presented a significant increase in the number of decayed and/or filled teeth. These children had 7.94 more chance of developing caries. Children who did not receive sealant were 1.8 more prone to have DMFT increment >0. Conclusion It appears that sealant placement was effective in preventing dental caries development. Moreover, the variables "risk" and "sealant placement" were predictors for DMFT increment in the studied children. PMID:21710092

  5. 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. PMID:10387579

  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. Salivary Bisphenol-A Levels due to Dental Sealant/Resin: A Case-Control Study in Korean Children

    PubMed Central

    Kim, Min-Ji; Jun, Eun-Joo; Kim, Jin-Bom

    2012-01-01

    Dental sealants and composite filling materials containing bisphenol-A (BPA) derivatives are increasingly used in children. The aim of this study was to evaluate the association between salivary BPA and the number of tooth surfaces filled with dental sealant, and to determine a cutoff BPA level. Salivary BPA concentration and the number of tooth surfaces filled with dental sealant/resin were determined in 124 age and gender matched children: 62 controls had no dental sealant/resin on their tooth surfaces and 62 cases had more than 4 tooth surfaces with dental sealant/resin. Analysis of covariance (ANCOVA) and conditional logistic regression were performed after controlling for age, gender, salivary flow rate, salivary buffer capacity, frequency of snacking, and frequency of tooth brushing. Salivary BPA levels were 0.002 to 8.305 µg/L. The BPA level of control (0.40 µg/L) was significantly lower than that of case (0.92 µg/L) after controlling for confounders (P = 0.026). Although the 90th BPA percentile had an adjusted OR of 4.58 (95% CI 1.04-20.26, P = 0.045), the significance disappeared in the conditional logistic model. There may be a relationship between salivary BPA level and dental sealant/resin. PMID:22969259

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

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

    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.

  9. 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.

  10. The origins of strain stiffening in fibrin networks

    NASA Astrophysics Data System (ADS)

    Jawerth, Louise; Muenster, Stefan; Weitz, David

    2012-02-01

    Fibrin networks form the structural scaffold of blood clots; their non-linear mechanical properties are crucial to stem the flow of blood at a site of vascular injury. A hallmark of these networks is strain stiffening: a stiffness that increases non-linearly as a network is strained. Deformations of the fibers and the network combine to control the mechanical properties of the bulk and must lead to the strain stiffening behavior of the networks; however, the details of this process are unknown. Here, we study fibrin networks undergoing shear on a confocal microscope and compare this to bulk rheological measurements. We track individual fiber branchpoints as function of system strain. We characterize the non-affinity of the motion and show that the low strain, linear regime corresponds to highly non-affine motion while the high strain, nonlinear regime corresponds to affine motion. Moreover, we show that the non-linear bulk response can be well approximated by considering the fibers to be linear elastic elements with soft compressive behavior and, therefore, is a result of the topology of the network itself rather than nonlinearity of its constituents.

  11. Fibrin solubilizing properties of certain anionic and cationic detergents.

    PubMed

    Chakrabarty, S

    1989-08-15

    The fibrinolytic (fibrin dissolving) properties of several anionic, cationic, nonionic and zwitterionic detergents were assessed in an in vitro fibrin agarose assay. Of the 4 anionic detergents tested, only sodium dodecyl sulfate (SDS) was found to be fibrinolytic. SDS was fibrinolytic either in the absence or presence of factor XIII. Four other cationic detergents were found to possess similar fibrinolytic properties. These cationic detergents were cetyltrimethylammonium bromide (CTAB), mix alkyltrimethyl ammonium bromide (MTAB), hexadecyltrimethylammonium bromide (HTAB) and cetylpyridium chloride (CPC). The nonionic (digitonin, triton X-100/tween 20) and zeitterionic (CHAPS, zeittergent 3-08) detergents were not fibrinolytic. Detergents mediated fibrinolysis, unlike that of tissue type plasminogen activator and urokinase, was independent of the presence of plasminogen. Non-detergents such as polyethylene glycol and highly charged compounds such as poly-1-lysine and poly-1-glutamic acid were not fibrinolytic. Fibrinolytic activity was observed for SDS and the cationic detergents at concentrations ranging from 0.1-10 percent. The effects of these fibrinolytic detergents (SDS, CTAB, MTAB, HTAB and CPC) on clot formation and on pre-formed clots were then assessed, using freshly drawn human venous blood. Incorporation of these detergents into blood inhibited the formation of clots in a concentration dependent manner. The detergents were also able to dissolve pre-formed clots in a similar fashion. SDS was found to be most potent in these properties. PMID:2510356

  12. 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.

  13. Migration of keratinocytes through tunnels of digested fibrin

    NASA Astrophysics Data System (ADS)

    Ronfard, Vincent; Barrandon, Yann

    2001-04-01

    We report here a hitherto undescribed form of cell migration. When a suspension of human keratinocytes is plated on a fibrin matrix, single cells invade the matrix and progress through it as rounded cells by dissolving the fibrin and thereby creating tunnels. These tunnels are cylindrical or helical, the latter being the result of constant change in the path of cellular advance around the helical axis. Helical tunnel formation is strongly promoted by epidermal growth factor. The rate of migration of the cell through the track of a helical tunnel (up to 2.1 mm per day) is about 7-fold greater than through a cylindrical tunnel. Pericellular fibrinolysis leading to tunnel formation depends on the presence of plasminogen in the medium and its conversion to plasmin by a cellular activator. Formation of tunnels requires that plasminogen activator be localized on the advancing surface of the keratinocyte; we propose that the tunnel is cylindrical when the site of release of plasmin is located at a fixed point on the cell surface and helical when the site of release precesses.

  14. Hemostats, sealants, and adhesives III: a new update as well as cost and regulatory considerations for components of the surgical toolbox.

    PubMed

    Spotnitz, William D; Burks, Sandra

    2012-10-01

    The hemostat, sealant, and adhesive components of the surgical toolbox continue to evolve and enter clinical practice at a rapid rate. The goal of this comprehensive, sequential review is to update these components to include those now available (February 2012) as well as to explore cost and regulatory factors that impact the development and use of these materials. A unique system of definitions for organizing these components based on group, category, and class is used as a means of improving the understanding and appropriate use of these materials. The system will be used here to present the most recent additions to the toolbox, which are evaluated based on safety, efficacy, usability, and cost. These new additions include pooled human plasma fibrinogen and thrombin embedded in an equine collagen patch for cardiac surgical hemostasis, polyethylene glycol (PEG) and human serum albumin for lung surgical pneumostasis, modified PEG and trilysine amine for spinal sealing, octyl and butyl lactoyl cyanoacrylate for vascular sealing, and a variety of octyl and butyl cyanoacrylates with or without dyes and/or polyester mesh for skin closure with the creation of a bacterial barrier. The system of definitions will also be used to clarify key strategies in the current health care environment for reducing costs and for increasing understanding of Food and Drug Administration regulatory decisions for these materials. PMID:22612730

  15. Surface topography and enamel-resin interface of pit and fissure sealants following visible light and argon laser polymerization: an in vitro study.

    PubMed

    Hicks, M J; Westerman, G H; Flaitz, C M; Powell, G L

    2000-01-01

    This in vitro study compared the effects of visible light and argon laser polymerization of pit and fissure sealants on surface topography and the enamel-sealant interface. Twenty caries-free human molars and premolars underwent soft tissue debridement and a fluoride-free prophylaxis. Fluoride-releasing sealant (UltraSeal XT Plus, South Jordan, UT 84095) was placed on the occlusal surfaces per the manufacturer's instructions, but underwent either visible-light polymerization for 30s (n = 10), or argon laser polymerization (0.231 J/cm2) for 10s (n = 10). The sealed teeth were thermocycled (500 cycles, 5 degrees to 50 degrees C) in artificial saliva. Surface morphology was evaluated by SEM. The teeth were sectioned for polarized light and SEM evaluation of the enamel-sealant interface, with two sections per tooth prepared for SEM. Phosphoric acid was used to unmask the enamel-sealant interface with one section; while the other section was not exposed to the phosphoric acid. Surface morphology of the sealant material was similar with both visible light and argon laser polymerization; however, there was a tendency for occasional areas of mild, focal cratering of the sealant surface with laser-curing. The junction between sealant and adjacent unsealed enamel was a relatively smooth transition without gaps, microspaces, crazing, exfoliative changes, or microfractures with both visible light and laser cured sealants. Acid treatment of the sections revealed resin tags which extended into the adjacent enamel for a considerable distance on SEM examination. The resin tas were similar in length and morphology with both visible light and argon laser curing. The enamel-sealant interface with visible light and laser curing showed intimate contact between the sealant and etched occlusal enamel with close apposition of the sealant. No microspaces were identified between the sealant and the occlusal enamel. An intact, interdigitating interface between a sealant and the adjacent

  16. The configuration of fibrin clots determines capillary morphogenesis and endothelial cell migration.

    PubMed

    Nehls, V; Herrmann, R

    1996-05-01

    In the living organism, capillary growth frequently occurs in a fibrin-rich extracellular matrix. The structure and the mechanical properties of fibrin clots are influenced by various macromolecules (i.e., hyaluronic acid and thrombospondin) and also by pH, ionic strength, and thrombin concentrations of the milieu in which they polymerize. The configuration (three-dimensional architecture) and the rigidity of fibrin clots correlate with their opacity measured by spectrophotometric absorbance readings at 350 nm. By using bovine pulmonary artery endothelial cells and bovine fibrinogen, we show here that transparent fibrin clots (A(350) < 1.0), polymerized at > or = pH 7.5 or in the presence of increased thrombin or sodium chloride concentrations, strongly stimulated capillary morphogenesis in vitro. In contrast, opaque fibrin gels (A(350) > 1.5), polymerized at pH 7.2 or in the presence of dextran, stimulated only the migration of endothelial cells but not capillary morphogenesis. We demonstrate that the angiomorphogenic effects of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) are strongly dependent on the structure of the fibrin clots. Our findings suggest that bFGF/VEGF primarily stimulate the proliferation of endothelial cells, whereas the three-dimensional architecture of the fibrin matrix is decisive for capillary morphogenesis. PMID:8992233

  17. Quantification and macroscopic modeling of the nonlinear viscoelastic behavior of strained gels with varying fibrin concentrations.

    PubMed

    Benkherourou, M; Guméry, P Y; Tranqui, L; Tracqui, P

    2000-11-01

    The mechanical properties of fibrin gels under uniaxial strains have been analyzed for low fibrin concentrations using a free-floating gel device. We were able to quantify the viscous and elastic moduli of gels with fibrin concentration ranging from 0.5 to 3 mg/ml, reporting significant differences of biogels moduli and dynamical response according to fibrin concentration. Furthermore, considering sequences of successively imposed step strains has revealed the strain-hardening properties of fibrin gels for strain amplitude below 5%. This nonlinear viscoelastic behavior of the gels has been precisely analyzed through numerical simulations of the overall gel response to the strain steps sequences. Phenomenological power laws relating the instantaneous and relaxed elasticity moduli to fibrin concentration have been validated, with concentration exponent in the order of 1.2 and 1.0, respectively. This continuous description of strain-dependent mechanical moduli was then used to simulate the biogel behavior when continuously time-varying strains are applied. We discuss how this experimental setup and associated macroscopic modeling of fibrin gels enable a further quantification of cell traction forces and mechanotransduction processes induced by biogel compaction or stretching. PMID:11077740

  18. 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.

  19. Tailoring silicone fuel tank sealants for high speed civil transport applications

    SciTech Connect

    Singh, N.; Johnson, B.; Cella, J.; Rich, J.

    1996-12-31

    Composition-property relationships of fumed silica filled, methyl trifluoropropyl polysiloxane fuel tank sealants for super sonic civil transport applications are discussed. Einstein-Guth-Gold-Medilla (EGGM) equation can be used to account for the increase in 100% modulus as a function of filler loadings at constant crosslinker concentrations. The tensile strength at break in these samples is linearly related to the 100% modulus due to the relative invariance of elongation at break and the linear stress-strain behavior. Samples made by changing the crosslinker level at constant filler loadings deviate away from the linear tensile strength vs. modulus relationship due to the accompanying decrease in elongation. Immersion in jet fuel and dry heat aging results in an increase in modulus and a decrease in elongation and tensile strength; primarily due to completion of crosslinking of the network. The volume swells of the sealants in Jet A was found to be independent of the level of the filler.

  20. Improving effectiveness of coke oven patching

    SciTech Connect

    Withrow, J.A.; McCollum, H.R.

    1982-01-01

    An effective patching program is essential to protect the battery against severe damage which would result from air, foul gas, and fuel gas leaks; and to keep it in operating condition for a reasonable life span. In addition to that basic purpose of patching, other areas such as heating efficiency, coke quality, and emissions performance can benefit from an effective program. Clairton Works and US Steel Research have made improvements in the patching program in several broad categories: equipment used for application of patching material, the patching material itself, and practices used in administration of the patching program. The equipment changes include a pusher machine ram-mounted roof patching unit and a new type of patching buggy for use with materials which tend to settle or cake. New materials have been formulated which develop a ceramic bond on the oven refractories and provide superior adherance. Battery Temperature Profiles, Charging Surveys, and Stack Observation Reports are used on a regular basis to identify critical areas for patching beyond those which can be identified by operating personnel on an incidental basis. This paper reviews each of these improvements in Clairton's patching program in terms of the equipment, materials, and practices per se and also discusses the results of implementing these changes.

  1. Platelet glycoprotein VI binds to polymerized fibrin and promotes thrombin generation.

    PubMed

    Mammadova-Bach, Elmina; Ollivier, Véronique; Loyau, Stéphane; Schaff, Mathieu; Dumont, Bénédicte; Favier, Rémi; Freyburger, Geneviève; Latger-Cannard, Véronique; Nieswandt, Bernhard; Gachet, Christian; Mangin, Pierre H; Jandrot-Perrus, Martine

    2015-07-30

    Fibrin, the coagulation end product, consolidates the platelet plug at sites of vascular injury and supports the recruitment of circulating platelets. In addition to integrin αIIbβ3, another as-yet-unidentified receptor is thought to mediate platelet interaction with fibrin. Platelet glycoprotein VI (GPVI) interacts with collagen and several other adhesive macromolecules. We evaluated the hypothesis that GPVI could be a functional platelet receptor for fibrin. Calibrated thrombin assays using platelet-rich plasma (PRP) showed that tissue factor-triggered thrombin generation was impaired in GPVI-deficient patients and reduced by the anti-GPVI Fab 9O12. Assays on reconstituted PRP and PRP from fibrinogen-deficient patients revealed a fibrinogen-dependent enhancement of thrombin generation, which relied on functional GPVI. The effect of GPVI was found to depend on fibrin polymerization. A binding assay showed a specific interaction between GPVI-Fc and fibrin, inhibited by the Fab 9O12. This Fab also reduced platelet adhesion to fibrin at low (300 s(-1)) and high (1500 s(-1)) wall shear rates. Platelets adherent to fibrin displayed shape change, exposure of procoagulant phospholipids, and the formation of small clots. When hirudinated blood was perfused at 1500 s(-1) over preformed fibrin-rich clots, the Fab 9O12 decreased the recruitment of platelets by up to 85%. This study identifies GPVI as a platelet receptor for polymerized fibrin with 2 major functions: (1) amplification of thrombin generation and (2) recruitment of circulating platelets to clots. These so-far-unrecognized properties of GPVI confer on it a key role in thrombus growth and stabilization. PMID:25977585

  2. Thrombin-dependent Incorporation of von Willebrand Factor into a Fibrin Network*

    PubMed Central

    Miszta, Adam; Pelkmans, Leonie; Lindhout, Theo; Krishnamoorthy, Ganeshram; de Groot, Philip G.; Hemker, Coenraad H.; Heemskerk, Johan W. M.; Kelchtermans, Hilde; de Laat, Bas

    2014-01-01

    Attachment of platelets from the circulation onto a growing thrombus is a process involving multiple platelet receptors, endothelial matrix components, and coagulation factors. It has been indicated previously that during a transglutaminase reaction activated factor XIII (FXIIIa) covalently cross-links von Willebrand factor (VWF) to polymerizing fibrin. Bound VWF further recruits and activates platelets via interactions with the platelet receptor complex glycoprotein Ib (GPIb). In the present study we found proof for binding of VWF to a fibrin monomer layer during the process of fibrinogen-to-fibrin conversion in the presence of thrombin, arvin, or a snake venom from Crotalus atrox. Using a domain deletion mutant we demonstrated the involvement of the C domains of VWF in this binding. Substantial binding of VWF to fibrin monomers persisted in the presence of the FXIIIa inhibitor K9-DON, illustrating that cross-linking via factor XIII is not essential for this phenomenon and suggesting the identification of a second mechanism through which VWF multimers incorporate into a fibrin network. Under high shear conditions, platelets were shown to adhere to fibrin only if VWF had been incorporated. In conclusion, our experiments show that the C domains of VWF and the E domain of fibrin monomers are involved in the incorporation of VWF during the polymerization of fibrin and that this incorporation fosters binding and activation of platelets. Fibrin thus is not an inert end product but partakes in further thrombus growth. Our findings help to elucidate the mechanism of thrombus growth and platelet adhesion under conditions of arterial shear rate. PMID:25381443

  3. Fibrin hydrogels for lentiviral gene delivery in vitro and in vivo

    PubMed Central

    Kidd, Martha; Shin, Seungjin; Shea, Lonnie D.

    2011-01-01

    Gene delivery from hydrogels represents a versatile approach for localized expression of tissue inductive factors than can promote cellular processes that lead to regeneration. Lentiviral gene therapy vectors were entrapped within fibrin hydrogels, either alone or complexes with hydroxylapatite (HA) nanoparticles. The inclusion of HA into the hydrogel led to the formation of small aggregates distributed throughout the hydrogel, with no obvious alteration of the pore structure outside the aggregates. The presence of HA slowed hydrogel degradation by collagenase and plasmin relative to fibrin alone, and also decreased the rate of cell migration. Lentivirus had similar release from the fibrin hydrogels formed with or without HA. The altered hydrogel properties suggest an interaction between the nanoparticle and fibrin, which may displace the virus from the particle leading to similar release profiles. Transgene expression by cells migrating into the hydrogel in vitro was reduced in the presence of HA, consistent with the role of cell migration on transgene expression. In vivo, lentivirus loaded fibrin hydrogels promoted localized transgene expression that increased through day 9 and decreased through day 14. For the fibrin only hydrogels, expression continued to decline after day 14. However, hydrogels with HA maintained this transgene expression level for an additional two weeks before declining. Immunostaining identified transgene primarily outside the fibrin-HA gel at day 9; however, at day 21, transgene expression was observed primarily within the fibrin-HA gel. The localized delivery of lentivirus provides an opportunity to enhance the bioactivity of fibrin hydrogels for a wide range of applications in regenerative medicine. PMID:21907251

  4. Fibrin Accumulation Secondary to Loss of Plasmin-Mediated Fibrinolysis Drives Inflammatory Osteoporosis in Mice

    PubMed Central

    Cole, Heather A.; Ohba, Tetsuro; Nyman, Jeffry S.; Hirotaka, Haro; Cates, Justin M. M.; Flick, Matthew J.; Degen, Jay L.; Schoenecker, Jonathan G.

    2015-01-01

    Objective Osteoporosis is a skeletal disorder characterized by low bone mass and increased bone fragility associated with aging, menopause, smoking, obesity, or diabetes. Persistent inflammation has been identified as an instigating factor in progressive bone loss. In addition to the role of fibrin in coagulation, inordinate fibrin deposition within a tissue matrix results in increased local inflammation. Given that fibrin accumulation is a hallmark of osteoporosis-related co-morbidities, we undertook this study to test the hypothesis that persistent fibrin deposition causes inflammatory osteoporosis. Methods Multiple imaging modalities, bone integrity metrics, and histologic analyses were employed to evaluate skeletal derangements in relation to fibrin deposition, circulating fibrinogen levels, and systemic markers of inflammation in mice that were plasminogen deficient and in plasminogen-deficient mice that were concomitantly either fibrinogen deficient or carrying a mutant form of fibrinogen lacking the αMβ2 binding motif. Results Mice generated with a genetic deficit in the key fibrinolytic protease, plasmin, uniformly developed severe osteoporosis. Furthermore, the development of osteoporosis was fibrin(ogen) dependent, and the derangements in the bone remodeling unit were mechanistically tied to fibrin(ogen)-mediated activation of osteoclasts via activation of the leukocyte integrin receptor αMβ2 on monocytes and secondary stimulation of osteoblasts by RANKL. Notably, the genetic elimination of fibrin(ogen) or the expression of a mutant form of fibrinogen retaining clotting function but lacking the αMβ2 binding motif prevented the degenerative skeletal phenotypes, resulting in normal local and systemic cytokine levels. Conclusion Taken together, these data reveal for the first time that fibrin promotes inflammation-driven systemic osteoporosis, which suggests a novel association between hemostasis, inflammation, and bone biology. PMID:24664548

  5. 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. PMID:9133673

  6. Calculating averted caries attributable to school-based sealant programs with a minimal data set

    PubMed Central

    Griffin, Susan O.; Jones, Kari; Crespin, Matthew

    2016-01-01

    Objectives We describe a methodology for school-based sealant programs (SBSP) to estimate averted cavities,(i.e.,difference in cavities without and with SBSP) over 9 years using a minimal data set. Methods A Markov model was used to estimate averted cavities. SBSP would input estimates of their annual attack rate (AR) and 1-year retention rate. The model estimated retention 2+ years after placement with a functional form obtained from the literature. Assuming a constant AR, SBSP can estimate their AR with child-level data collected prior to sealant placement on sealant presence, number of decayed/filled first molars, and age. We demonstrate the methodology with data from the Wisconsin SBSP. Finally, we examine how sensitive averted cavities obtained with this methodology is if an SBSP were to over or underestimate their AR or 1-year retention. Results Demonstrating the methodology with estimated AR (= 7 percent) and 1-year retention (= 92 percent) from the Wisconsin SBSP data, we found that placing 31,324 sealants averted 10,718 cavities. Sensitivity analysis indicated that for any AR, the magnitude of the error (percent) in estimating averted cavities was always less than the magnitude of the error in specifying the AR and equal to the error in specifying the 1-year retention rate. We also found that estimates of averted cavities were more robust to misspecifications of AR for higher- versus lower-risk children. Conclusions With Excel (Microsoft Corporation, Redmond, WA, USA) spreadsheets available upon request, SBSP can use this methodology to generate reasonable estimates of their impact with a minimal data set. PMID:24423023

  7. Influence of light-curing mode on the cytotoxicity of resin-based surface sealants

    PubMed Central

    2014-01-01

    Background Surface sealants have been successfully used in the prevention of erosive tooth wear. However, when multiple tooth surfaces should be sealed, the light-curing procedure is very time-consuming. Therefore, the aim of this study was to investigate whether reduced light-curing time (while maintaining similar energy density) has an influence on resin-based surface sealant cytotoxicity. Methods Bovine dentine discs were treated as follows: group 1: untreated, groups 2–5: Seal&Protect and groups 6–9: experimental sealer. Groups 2 and 6 were light-cured (VALO LED light-curing device) for 40 s (1000 mW/cm2), groups 3 and 7 for 10 s (1000 mW/cm2), groups 4 and 8 for 7 s (1400 mW/cm2) and groups 5 and 9 for 3 s (3200 mW/cm2). Later, materials were extracted in culture medium for 24 h, and released lactate dehydrogenase (LDH) activity as a measure of cytotoxicity was determined photometrically after cells (dental pulp cells and gingival fibroblasts) were exposed to the extracts for 24 h. Three independent experiments, for both sample preparation and cytotoxicity testing, were performed. Results Overall, lowest cytotoxicity was observed for the unsealed control group. No significant influence of light-curing settings on the cytotoxicity was observed (p = 0.537 and 0.838 for pulp cells and gingival fibroblasts, respectively). No significant difference in the cytotoxicity of the two sealants was observed after light-curing with same light-curing settings (group 2 vs. 6, 3 vs. 7, 4 vs. 8 and 5 vs. 9: p > 0.05, respectively). Conclusions Shortening the light-curing time, while maintaining constant energy density, resulted in no higher cytotoxicity of the investigated sealants. PMID:24885810

  8. Effectiveness of fluoride sealant in the prevention of carious lesions around orthodontic brackets: an OCT evaluation

    PubMed Central

    Pithon, Matheus Melo; Santos, Mariana de Jesus; de Souza, Camilla Andrade; Leão, Jorge César Borges; Braz, Ana Karla Souza; de Araujo, Renato Evangelista; Tanaka, Orlando Motohiro; Oliveira, Dauro Douglas

    2015-01-01

    Abstract Objective: This article aimed to evaluate in vitro the efficiency of Pro Seal fluoride sealant application in the prevention of white spot lesions around orthodontic brackets. Material and Methods: Brackets were bonded to the buccal surface of bovine incisors, and five groups were formed (n = 15) according to the exposure of teeth to oral hygiene substances and the application of enamel sealant: G1 (control), only brushing was performed with 1.450 ppm fluoride; G2 (control) brushing associated with the use of mouthwash with 225 ppm fluoride; G3, only Pro Seal sealant application was performed with 1.000 ppm fluoride; G4 Pro Seal associated with brushing; G5 Pro Seal associated with brushing and mouthwash. Experimental groups alternated between pH cycling and the procedures described. All specimens were kept at a temperature of 37 °C throughout the entire experiment. Both brushing and immersion in solutions were performed within a time interval of one minute, followed by washing in deionized water three times a day for 28 days. Afterwards, an evaluation by Optical Coherence Tomography (OCT) of the spectral type was performed. In each group, a scanning exam of the white spot lesion area (around the sites where brackets were bonded) and depth measurement of carious lesions were performed. Analysis of variance (ANOVA) was applied to determine whether there were significant differences among groups. For post hoc analysis, Tukey test was used. Results: There was statistically significant difference between groups 1 and 2 (p = 0.003), 1 and 3 (p = 0.008), 1 and 4 (p = 0.000) and 1 and 5 (p = 0.000). The group in which only brushing was performed (Group 1) showed deeper enamel lesion. Conclusion: Pro Seal sealant alone or combined with brushing and/or brushing and the use of a mouthwash with fluoride was more effective in protecting enamel, in comparison to brushing alone. PMID:26691968

  9. ERTS-1 anomalous dark patches

    NASA Technical Reports Server (NTRS)

    Strong, A. E. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Through combined use of imagery from ERTS-1 and NOAA-2 satellites was found that when the sun elevation exceeds 55 degrees, the ERTS-1 imagery is subject to considerable contamination by sunlight even though the actual specular point is nearly 300 nautical miles from nadir. Based on sea surface wave slope information, a wind speed of 10 knots will theoretically provide approximately 0.5 percent incident solar reflectance under observed ERTS multispectral scanner detectors. This reflectance nearly doubles under the influence of a 20 knot wind. The most pronounced effect occurs in areas of calm water where anomalous dark patches are observed. Calm water at distances from the specular point found in ERTS scenes will reflect no solar energy to the multispectral scanner, making these regions stand out as dark areas in all bands in an ocean scene otherwise comprosed by a general diffuse sunlight from rougher ocean surfaces. Anomalous dark patches in the outer parts of the glitter zones may explain the unusual appearance of some scenes.

  10. Exogenous pigment in Peyer's patches

    SciTech Connect

    Shepherd, N.A.; Crocker, P.R.; Smith, A.P.; Levison, D.A.

    1987-01-01

    Dark brown granular pigment was found consistently in macrophages in the deep aspect of adult Peyer's patches. Tissue sections from intestinal resections of 35 patients with a variety of pathologic diagnoses and of seven postmortem cases with no evidence of gastrointestinal disease were examined for the presence of this pigment. It was found in all patients over the age of 6 years (34 cases) but was not found in any children below that age (eight cases). Scanning electron microscopy with secondary and backscattered electron imaging and x-ray energy spectroscopy were performed on routine histologic sections. The pigmented macrophages contained aluminum and silicon, diffusely present throughout the cytoplasm, and numerous discrete foci of titanium. Pigment containing these same elements has also been found around dilated submucosal lymphatics, in mesenteric lymph nodes, and in some transmural inflammatory aggregates of Crohn's disease. The pigment probably is derived from the diet and actively taken up by Peyer's patches, which are able to incorporate inert particulate matter.

  11. Time to adoption of an innovation by dentists in private practice: sealant utilization.

    PubMed

    Chapko, M K

    1991-01-01

    Dentists can be divided into five adoption categories based upon their time of adoption of pit and fissure sealants: innovators, early adopters, early majority, late majority, and laggards. The differences among dentists in the five adoption categories were examined for four classes of variables: practice characteristics, dentist characteristics, communication of information, and practice environment. Questionnaires were mailed in September 1984 to a random sample (N = 521) of Washington State dentists in general practices. A total of 376 completed questionnaires were returned, for a response rate of 72 percent. Adoption of sealants proceeded as follows: 5 percent of dentists through 1973, 24 percent through 1979, 50 percent through 1982, and 75 percent through 1984. Adoption category was related to percent of assistants who were certified, delegation to assistants and hygienists, magnitude of the fees charged by the practice, number of staff meetings per month, the dentist having been an officer in a dental organization, year the dentist adopted other new technologies, dentist's self-rating of willingness to try new things, percent of patients who are children, and percent of the dentist's colleagues who used sealants. These data lend some support to the two-stage or opinion-leader model of diffusion and suggest that new technologies can be promoted by first influencing dentists who consistently adopt early. PMID:1920266

  12. An analysis of pipe flange connections using epoxy adhesives/anaerobic sealant instead of gaskets

    SciTech Connect

    Sawa, T.; Sasaki, R.; Yoneno, M.

    1995-11-01

    This paper deals with the strength and the sealing performance of pipe flange connections combining the bonding force of adhesives with the clamping force of bolts. The epoxy adhesives or anaerobic sealants are bonded at the interface partially instead of gaskets in pipe flange connections. The stress distribution in the epoxy adhesives (anaerobic sealant), which governs the sealing performance, and the variations in axial bolt force are analyzed, using an axisymmetrical theory of elasticity, when an internal pressure is applied to a connection in which two pipe flanges are clamped together buy bolts and nuts with an initial clamping force after being joined by epoxy adhesives or anaerobic sealant. In addition, a method for estimating the strength of the combination connection is demonstrated. Experiments are performed and the analytical results are consistent with the experimental results concerning the variation in axial bolt force and the strength of combination connections. It can be seen that the strength of connections increases with a decrease in the bolt pitch circle diameter. Furthermore, it is seen that the sealing performance of such combination connections in which the interface is bonded partially is improved over that of pipe flange connections with metallic gaskets.

  13. Color and opacity of composites protected with surface sealants and submitted to artificial accelerated aging

    PubMed Central

    Aguilar, Fabiano Gamero; Roberti Garcia, Lucas da Fonseca; Cruvinel, Diogo Rodrigues; Sousa, Ana Beatriz Silva; de Carvalho Panzeri Pires-de-Souza, Fernanda

    2012-01-01

    Objectives: To evaluate the color similarity, stability and opacity of composites (TPH, Charisma, and Concept, shade A2) protected with surface sealants (Fortify Plus and Biscover) and cyanoacrylate (Super Bonder). Methods: Forty specimens of each composite were made and separated into 4 groups (n=10) according to the surface protection: GI - without sealant; GII - cyanoacrylate; GIII - Fortify Plus; GIV - Biscover. Color and opacity readings were taken before and after Artificial Acelerated Aging (AAA) and the values obtained for color stability were submitted to statistical analysis by 2-way ANOVA and Bonferroni’s test (P<.05). The values acquired for color similarity were submitted to 1-way ANOVA and Tukey’s test (P<.05). The specimen sufaces were compared before and after AAA using Scanning Electronic Microscopy (SEM). Results: Studied composites did not present the same values for the coordinates L*, a* and b * before AAA, indicating that there was no color similarity among them. All composites presented color alteration after AAA with clinically unacceptable values. Protected groups presented lower opacity variation after AAA, in comparison with the control goup. SEM evaluation demonstrated that AAA increased the surface irregularities in all of the studied groups. Conclusion: Surface sealants were not effective in maintaining composite color, but were able to maintain opacity. PMID:22229004

  14. 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

  15. Acute fibrinous and organizing pneumonia: A rare form of nonbacterial pneumonia.

    PubMed

    Saxena, Prashant; Kumar, Kuldeep; Mittal, Sarita; Goyal, Nidhi; Trikha, Sahil; Vashisth, Arti

    2016-04-01

    Acute fibrinous and organizing pneumonia (AFOP) is a rare disease characterized by bilateral basilar infiltrates and histological findings of organizing pneumonia and intra-alveolar fibrin in the form of "fibrin balls." Here, we report a 43-year-old female with complaints of fever, dry cough, and shortness of breath with hypoxemia. High-resolution computed tomography thorax revealed diffuse confluent consolidation in bilateral lung zones. Bronchoscopy and transbronchial biopsy revealed features of AFOP. With prednisolone treatment, there was an improvement in her condition. AFOP is a rare disease and should be taken into consideration and differential diagnosis of severe acute pneumonias with no significant comorbidities. PMID:27303141

  16. Acute fibrinous and organizing pneumonia: A rare form of nonbacterial pneumonia

    PubMed Central

    Saxena, Prashant; Kumar, Kuldeep; Mittal, Sarita; Goyal, Nidhi; Trikha, Sahil; Vashisth, Arti

    2016-01-01

    Acute fibrinous and organizing pneumonia (AFOP) is a rare disease characterized by bilateral basilar infiltrates and histological findings of organizing pneumonia and intra-alveolar fibrin in the form of “fibrin balls.” Here, we report a 43-year-old female with complaints of fever, dry cough, and shortness of breath with hypoxemia. High-resolution computed tomography thorax revealed diffuse confluent consolidation in bilateral lung zones. Bronchoscopy and transbronchial biopsy revealed features of AFOP. With prednisolone treatment, there was an improvement in her condition. AFOP is a rare disease and should be taken into consideration and differential diagnosis of severe acute pneumonias with no significant comorbidities. PMID:27303141

  17. Meniscal Repair of Degenerative Horizontal Cleavage Tears Using Fibrin Clots

    PubMed Central

    Kamimura, Tamiko; Kimura, Masashi

    2014-01-01

    Background: Presently, the treatment options available for patients with horizontal degenerative cleavage tears of the meniscus are limited. These tears are considered an indication for partial or subtotal meniscectomy because when the tear is located within an avascular area, it is difficult to induce healing. However, meniscectomy is not ideal because it disrupts the normal anatomical structure and function of the meniscus. Purpose: To examine the clinical and arthroscopic outcomes following meniscal repair of degenerative horizontal cleavage tears using fibrin clots. Study Design: Case series; Level of evidence, 4. Methods: Vertical sutures were placed in the meniscal tear, and the cleft was filled with fibrin clots before the sutures were tightened. We repaired 18 menisci in 18 consecutive eligible patients using a previously described technique. Three patients with anterior cruciate ligament (ACL) injury who underwent simultaneous ACL reconstruction and 5 patients who did not undergo follow-up arthroscopy within 12 months were excluded. The remaining 10 menisci in 10 patients were evaluated in this study. The mean age of the patients was 35.8 ± 16.5 years, and the mean postoperative follow-up time was 40.8 ± 5.4 months. Pre- and postoperative Lysholm scores, International Knee Documentation Committee (IKDC) subjective scores, and Tegner activity levels were compared. The arthroscopy findings were evaluated at a mean postoperative time of 6.7 ± 2.9 months. Results: The mean Lysholm score improved significantly from 69.3 ± 16.3 points preoperatively to 95.4 ± 3.6 points postoperatively (P < .005). The mean IKDC subjective score also improved significantly from 26.5% ± 19.0% preoperatively to 87.8% ± 7.5% postoperatively (P < .001). The Tegner activity level recovered to the preinjury level in 6 patients and to 1 level below the preinjury level in 4 patients. The follow-up arthroscopies showed complete healing in 7 patients (70%) and incomplete healing in

  18. 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

  19. 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

  20. Electrochemical cell with a cadmium patch electrode

    SciTech Connect

    Ames, A.E.; Bloom, S.M.; Hoffman, A.; Norland, K.

    1980-01-22

    A cadmium patch laminar electrode, comprising a dispersion of particulate cadmium in a binder matrix on a conductive plastic substrate is prepared by contacting a zinc patch electrode comprising a dispersion of particulate zinc in a binder matrix on a conductive plastic substrate with an aqueous solution of a cadmium salt. The cadmium patch electrode can be used in a primary electrochemical cell such as that employing a manganese dioxide cathode and a cadmium chloride electrolyte.

  1. 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.

  2. 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.

  3. 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.

  4. Transdermal fentanyl patches in small animals.

    PubMed

    Hofmeister, Erik H; Egger, Christine M

    2004-01-01

    Fentanyl citrate is a potent opioid that can be delivered by the transdermal route in cats and dogs. Publications regarding transdermal fentanyl patches were obtained and systematically reviewed. Seven studies in cats and seven studies in dogs met the criteria for inclusion in this review. Dogs achieved effective plasma concentrations approximately 24 hours after patch application. Cats achieved effective plasma concentrations 7 hours after patch application. In dogs, transdermal fentanyl produced analgesia for up to 72 hours, except for the immediate 0- to 6-hour postoperative period. In cats, transdermal fentanyl produced analgesia equivalent to intermittent butorphanol administration for up to 72 hours following patch application. PMID:15533967

  5. [THROMBIN-MEDIATED EFFECTS OF BLOOD MICROPARTICLES ON FORMATION, STRUCTURE, AND STABILITY OF FIBRIN CLOTS].

    PubMed

    Nabiullina, R M; Mustafin, I G; Ataullakhanov, F I; Litvinov, R I; Zubairova, L D

    2015-07-01

    The effects of blood microparticles (MPs) on the dynamics of fibrin polymerization, clot structure and susceptibility to fibrinolysis were studied. Kinetics of fibrin polymerization, fibrinolysis, thrombin generation in platelet-free, microparticle-depleted and microparticle-depleted plasma replenished with cephalin, from healthy donors were analyzed in parallel. MPs have profound effects on all stages of fibrin formation, decrease its turbidity. All parameters obtained in the absence of MPs were recovered after reconstitution of phospholipids. Thrombin generation rates were reduced in the absence of MPs. In the presence of MPs the fibrin networks had less poro us structures with thinner fibers, while clots formed in the absence of MPs had larger pores and were built of thicker fibers. Clots formed in the presence of MPs were significantly more resistant to fibrinolysis. Results show that normally circulating MPs can support the formation of stable clots at the sites of vascular injury. PMID:26591054

  6. Fibrin Clot Structure and Mechanics Associated with Specific Oxidation of Methionine Residues in Fibrinogen

    PubMed Central

    Weigandt, Katie M.; White, Nathan; Chung, Dominic; Ellingson, Erica; Wang, Yi; Fu, Xiaoyun; Pozzo, Danilo C.

    2012-01-01

    Using a combination of structural and mechanical characterization, we examine the effect of fibrinogen oxidation on the formation of fibrin clots. We find that treatment with hypochlorous acid preferentially oxidizes specific methionine residues on the α, β, and γ chains of fibrinogen. Oxidation is associated with the formation of a dense network of thin fibers after activation by thrombin. Additionally, both the linear and nonlinear mechanical properties of oxidized fibrin gels are found to be altered with oxidation. Finally, the structural modifications induced by oxidation are associated with delayed fibrin lysis via plasminogen and tissue plasminogen activator. Based on these results, we speculate that methionine oxidation of specific residues may be related to hindered lateral aggregation of protofibrils in fibrin gels. PMID:23283239

  7. Patch voltage clamp of squid axon membrane.

    PubMed

    Fishman, H M

    1975-12-01

    A small area (patch) of the external surface of a squid axon can be "isolated" electrically from the surrounding bath by means of a pair of concentric glass pipettes. The seawater-filled inner pipette makes contact with the axon and constitutes the external access to the patch. The outer pipette is used to direct flowing sucrose solution over the area surrounding the patch of membrane underlying the inner pipette. Typically, sucrose isolated patches remain in good condition (spike amplitude greater than 90 mV) for periods of approximately one half hour. Patches of axon membrane which had previously been exposed to sucrose solution were often excitable. Membrane survival of sucrose treatment apparently arises from an outflow of ions from the axon and perhaps satellite cells into the interstitial cell space surrounding the exolemma. Estimate of the total access resistance (electrode plus series resistance) to the patch is about 100 komega (7 omega cm2). Patch capacitance ranges from 10-100 pF, which suggests areas of 10(-4) to 10(-5) cm2 and resting patch resistances of 10-100 Momega. Shunt resistance through the interstitial space exposed to sucrose solution, which isolates the patch, is typically 1-2 Momega. These parameters indicate that good potential control and response times can be achieved on a patch. Furthermore, spatial uniformity is demonstrated by measurement of an exoplasmic isopotential during voltage clamp of an axon patch. The method may be useful for other preparations in which limited membrane area is available or in special instances such as in the measurement of membrane conduction noise. PMID:1214276

  8. 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/

  9. 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

  10. Transfer of innovation for advancement in dentistry: a case study on pit and fissure sealants' use in Japan.

    PubMed

    Nakata, M; Kuriyama, S; Mitsuyasu, K; Morimoto, M; Tomioka, K

    1989-12-01

    The implementation of scientific innovations is most important in advancing both dental care systems and dental science. However, scientific knowledge in dentistry is not always well implemented. In this paper the phases of development, diffusion, adoption and utilization of sealants are examined as one example of the way in which a relatively new innovation still needs more effort to ensure its wider use. Discussions with a dental manufacturer on the development of sealant materials and an investigation into the adoption of sealants in the national health insurance system of Japan were undertaken. Questionnaires regarding the education on sealants offered in dental schools and dental hygienist schools, and questionnaires to dental practitioners concerning their use of sealants, were used and analysed. The analysis of the various factors showed that the transfer of knowledge through the educational system is the most significant step in the uptake of innovations. Legality, insurance coverage and patient acceptance are significantly associated with the phase of adoption. A model of transfer pathways for new dental innovations is proposed. PMID:2606563

  11. [APPLICATION OF FISTULA PLUG WITH THE FIBRIN ADHESIVE IN TREATMENT OF RECTAL FISTULAS].

    PubMed

    Aydinova, P R; Aliyev, E A

    2015-05-01

    Results of surgical treatment of 21 patients, suffering high transsphincteric and extrasphincteric rectal fistulas, were studied. In patients of Group I the fistula passage was closed, using fistula plug obturator; and in patients of Group II--by the same, but preprocessed by fibrin adhesive. The fistula aperture germeticity, prophylaxis of rude cicatrices development in operative wound zone, promotion of better fixation of bioplastic material were guaranteed, using fistula plug obturator with preprocessing, using fibrin adhesive. PMID:26419026

  12. Efficient therapy of ischaemic lesions with VEGF121-fibrin in an animal model of systemic sclerosis

    PubMed Central

    Allipour Birgani, Shadab; Mailänder, Marion; Wasle, Ines; Dietrich, Hermann; Gruber, Johann; Distler, Oliver; Sgonc, Roswitha

    2016-01-01

    Background In systemic sclerosis (SSc), chronic and uncontrolled overexpression of vascular endothelial growth factor (VEGF) results in chaotic vessels, and intractable fingertip ulcers. Vice versa, VEGF is a potent mediator of angiogenesis if temporally and spatially controlled. We have addressed this therapeutic dilemma in SSc by a novel approach using a VEGF121 variant that covalently binds to fibrin and gets released on demand by cellular enzymatic activity. Using University of California at Davis (UCD)-206 chickens, we tested the hypothesis that cell-demanded release of fibrin-bound VEGF121 leads to the formation of stable blood vessels, and clinical improvement of ischaemic lesions. Methods Ninety-one early and late ischaemic comb and neck skin lesions of UCD-206 chickens were treated locally with VEGF121-fibrin, fibrin alone, or left untreated. After 1 week of treatment the clinical outcome was assessed. Angiogenesis was studied by immunofluorescence staining of vascular markers quantitatively analysed using TissueQuest. Results Overall, 79.3% of the lesions treated with VEGF121-fibrin showed clinical improvement, whereas 71.0% of fibrin treated controls, and 93.1% of untreated lesions deteriorated. This was accompanied by significantly increased growth of stable microvessels, upregulation of the proangiogenic VEGFR-2 and its regulator TAL-1, and increase of endogenous endothelial VEGF expression. Conclusions Our findings in the avian model of SSc suggest that cell-demanded release of VEGF121 from fibrin matrix induces controlled angiogenesis by differential regulation of VEGFR-1 and VEGFR-2 expression, shifting the balance towards the proangiogenic VEGFR-2. The study shows the potential of covalently conjugated VEGF-fibrin matrices for the therapy of ischaemic lesions such as fingertip ulcers. PMID:26362758

  13. Molecular imaging of fibrin in a breast cancer xenograft mouse model

    PubMed Central

    Uppal, Ritika; Medarova, Zdravka; Farrar, Christian T.; Dai, Guangping; Moore, Anna; Caravan, Peter

    2013-01-01

    Rationale and objectives Fibrin deposition has been indicated within the stroma of a majority of solid tumors. Here we assess the feasibility of using the established fibrin-specific probe EP-2104R for the noninvasive imaging of fibrin in the context of breast cancer. Methods EP-2104R, untargeted Gd-DTPA and a newly synthesized non-fibrin binding control linear peptide (CLP) were compared using steady-state and dynamic contrast enhanced MR imaging in a breast cancer xenograft mouse model at 9.4T. Results EP-2104R transiently enhanced both the tumor core and periphery, but only the enhancement in the tumor periphery persisted even 90 min after EP-2104R administration. However, untargeted Gd-DTPA and CLP are not retained in the tumor periphery. The half-life of EP-2104R in the tumor periphery (103±18 min) is significantly longer (p<0.05) than either Gd-DTPA (29.6±2.4 min) or CLP (42.4±1.5 min), but the rate of clearance is similar for all the three probes from the tumor core. The presence of high concentrations of fibrin in the tumor periphery was corroborated using immuno-histochemistry with a fibrin-specific antibody. Conclusions The persistent enhancement observed in the tumor periphery with EP-2104R is likely a result of its fibrin-specific binding rather than its size and demonstrates the feasibility of EP-2104R for molecular imaging of fibrin in tumor stroma. PMID:22960948

  14. Gravity Survey of the Rye Patch KGRA, Rye Patch, Nevada

    NASA Astrophysics Data System (ADS)

    Mcdonald, M. R.; Gosnold, W. D.

    2011-12-01

    The Rye Patch Known Geothermal Resource Area (KGRA) is located in Pershing County Nevada on the west side of the Humboldt Range and east of the Rye Patch Reservoir approximately 200 km northeast of Reno, Nevada. Previous studies include an earlier gravity survey, 3-D seismic reflection, vertical seismic profiling (VSP) on a single well, 3-D seismic imaging, and a report of the integrated seismic studies. Recently, Presco Energy conducted an aeromagnetic survey and is currently in the process of applying 2-D VSP methods to target exploration and production wells at the site. These studies have indicated that geothermal fluid flow primarily occurs along faults and fractures and that two potential aquifers include a sandstone/siltstone member of the Triassic Natchez Pass Formation and a karst zone that occurs at the interface between Mesozoic limestone and Tertiary volcanics. We hypothesized that addition of a high-resolution gravity survey would better define the locations, trends, lengths, and dip angles of faults and possible solution cavity features. The gravity survey encompassed an area of approximately 78 km2 (30 mi2) within the boundary of the KGRA along with portions of 8 sections directly to the west and 8 sections directly to the east. The survey included 203 stations that were spaced at 400 m intervals. The simple Bouguer anomaly patterns were coincident with elevation, and those patterns remained after terrain corrections were performed. To remove this signal, the data were further processed using wave-length (bandpass) filtering techniques. The results of the filtering and comparison with the recent aeromagnetic survey indicate that the location and trend of major fault systems can be identified using this technique. Dip angles can be inferred by the anomaly contour gradients. By further reductions in the bandpass window, other features such as possible karst solution channels may also be recognizable. Drilling or other geophysical methods such as a

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

    PubMed Central

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

    2012-01-01

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

  16. 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. PMID:12195697

  17. 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.

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2007-05-01

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

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

    PubMed

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

    2016-09-01

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

  1. Fibrin Gel as an Injectable Biodegradable Scaffold and Cell Carrier for Tissue Engineering

    PubMed Central

    Li, Yuting; Meng, Hao; Liu, Yuan

    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. PMID:25853146

  2. Fibrin-Loaded Porous Poly(Ethylene Glycol) Hydrogels as Scaffold Materials for Vascularized Tissue Formation

    PubMed Central

    Jiang, Bin; Waller, Thomas M.; Larson, Jeffery C.; Appel, Alyssa A.

    2013-01-01

    Vascular network formation within biomaterial scaffolds is essential for the generation of properly functioning engineered tissues. In this study, a method is described for generating composite hydrogels in which porous poly(ethylene glycol) (PEG) hydrogels serve as scaffolds for mechanical and structural support, and fibrin is loaded within the pores to induce vascularized tissue formation. Porous PEG hydrogels were generated by a salt leaching technique with 100–150-μm pore size and thrombin (Tb) preloaded within the scaffold. Fibrinogen (Fg) was loaded into pores with varying concentrations and polymerized into fibrin due to the presence of Tb, with loading efficiencies ranging from 79.9% to 82.4%. Fibrin was distributed throughout the entire porous hydrogels, lasted for greater than 20 days, and increased hydrogel mechanical stiffness. A rodent subcutaneous implant model was used to evaluate the influence of fibrin loading on in vivo response. At weeks 1, 2, and 3, all hydrogels had significant tissue invasion, but no difference in the depth of invasion was found with the Fg concentration. Hydrogels with fibrin loading induced more vascularization, with a significantly higher vascular density at 20 mg/mL (week 1) and 40 mg/mL (weeks 2 and 3) Fg concentration compared to hydrogels without fibrin. In conclusion, we have developed a composite hydrogel that supports rapid vascularized tissue ingrowth, and thus holds great potential for tissue engineering applications. PMID:23003671

  3. 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.

  4. 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

  5. Bulkhead interface chassis for optical fiber patching

    NASA Astrophysics Data System (ADS)

    George, M.

    1985-06-01

    An optical fiber patch panel was designed to meet the changing needs of optical fiber communication link installations. This paper deals with the specification and construction details of the Bulkhead Interface Chassis patch panel. Included is ordering information for the commercial parts needed and shop drawings of the pieces to be machined.

  6. Tendon graft substitutes-rotator cuff patches.

    PubMed

    Coons, David A; Alan Barber, F

    2006-09-01

    Over the past few years, many biologic patches have been developed to augment repairs of large or complex tendon tears. These patches include both allograft and xenografts. Regardless of their origins, these products are primarily composed of purified type I collagen. Many factors should be considered when choosing an augmentation patch including tissue origin, graft processing, cross-linking, clinical experience, and physical properties. The purpose of this article is to familiarize the sports medicine community with several tendon augmentation grafts: GraftJacket (Wright Medical Technology, Arlington, TN), CuffPatch (Organogenesis, Canton, MA, licensed to Arthrotek, Warsaw, IN), Restore (Depuy, Warsaw, IN), Zimmer Collagen Repair (Permacol) patch (Tissue Science Laboratories Covington, GA, licensed to Zimmer, Warsaw, IN), TissueMend (TEI Biosciences, Boston, MA, licensed to Stryker Howmedica Osteonics, Kalamazoo, MI), OrthoADAPT (Pegasus Biologics, Irvine, CA), and BioBlanket (Kensey Nash, Exton, PA). PMID:17135966

  7. Engineered Tissue Patch for Cardiac Cell Therapy

    PubMed Central

    Zhang, Jianyi

    2015-01-01

    Opinion statement Cell therapy can be administered via injections delivered directly into the myocardium or as engineered cardiac tissue patches, which are the subject of this review. Engineered cardiac patches can be created from sheets of interconnected cells or by suspending the cells in a scaffold of material that is designed to mimic the native extracellular matrix. The sheet-based approach produces patches with well-aligned and electronically coupled cardiomyocytes, but cell-containing scaffolds are more readily vascularized by the host's circulatory system and, consequently, are currently more suitable for applications that require a thicker patch. Cell patches can also be modified for the co-delivery of peptides that may promote cell survival and activate endogenous repair mechanisms; nevertheless, techniques for controlling inflammation, limiting apoptosis, and improving vascular growth need continue to be developed to make it a therapeutic modality for patients with myocardial infarction. PMID:26122908

  8. Safe patch version 0.9 user manual

    SciTech Connect

    Kelley, M

    1999-03-01

    The SafePatch version 0.9 provides automated analysis of network-based computer systems to determine the status of security patches and distributes needed patches. SafePatch determines what patches need to be installed and what patches are installed on a system. SafePatch will distribute needed patches to the remote system for later installation. For those patches that are installed, SafePatch checks the permissions and ownership of the files referenced in the patch and reports on the attributes that differ from those recommended by the patch. SafePatch also ensures that the system software is authentic (that is, belonging to either a release of an operating system or a patch). The process SafePatch uses to authenticate the software on a system is more reliable and secure than other vendor-specific tools. SafePatch compares the remote system's files with the files from the patches to determine what is actually installed and what needs to be installed. This approach ensures accurate reporting of a system's patch status. It also allows SafePatch to identify files that do not belong to either the original system distribution (for example, Solaris 2.5) or to any patch. These unidentified files may be customized or trojan. Either way these files should be investigated further to determine their exact origin.

  9. 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

  10. 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.

  11. Oracle Applications Patch Administration Tool (PAT) Beta Version

    Energy Science and Technology Software Center (ESTSC)

    2002-01-04

    PAT is a Patch Administration Tool that provides analysis, tracking, and management of Oracle Application patches. This includes capabilities as outlined below: Patch Analysis & Management Tool Outline of capabilities: Administration Patch Data Maintenance -- track Oracle Application patches applied to what database instance & machine Patch Analysis capture text files (readme.txt and driver files) form comparison detail report comparison detail PL/SQL package comparison detail SQL scripts detail JSP module comparison detail Parse and loadmore » the current applptch.txt (10.7) or load patch data from Oracle Application database patch tables (11i) Display Analysis -- Compare patch to be applied with current Oracle Application installed Appl_top code versions Patch Detail Module comparison detail Analyze and display one Oracle Application module patch. Patch Management -- automatic queue and execution of patches Administration Parameter maintenance -- setting for directory structure of Oracle Application appl_top Validation data maintenance -- machine names and instances to patch Operation Patch Data Maintenance Schedule a patch (queue for later execution) Run a patch (queue for immediate execution) Review the patch logs Patch Management Reports« less

  12. Oracle Applications Patch Administration Tool (PAT) Beta Version

    SciTech Connect

    2002-01-04

    PAT is a Patch Administration Tool that provides analysis, tracking, and management of Oracle Application patches. This includes capabilities as outlined below: Patch Analysis & Management Tool Outline of capabilities: Administration Patch Data Maintenance -- track Oracle Application patches applied to what database instance & machine Patch Analysis capture text files (readme.txt and driver files) form comparison detail report comparison detail PL/SQL package comparison detail SQL scripts detail JSP module comparison detail Parse and load the current applptch.txt (10.7) or load patch data from Oracle Application database patch tables (11i) Display Analysis -- Compare patch to be applied with current Oracle Application installed Appl_top code versions Patch Detail Module comparison detail Analyze and display one Oracle Application module patch. Patch Management -- automatic queue and execution of patches Administration Parameter maintenance -- setting for directory structure of Oracle Application appl_top Validation data maintenance -- machine names and instances to patch Operation Patch Data Maintenance Schedule a patch (queue for later execution) Run a patch (queue for immediate execution) Review the patch logs Patch Management Reports

  13. 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.

  14. PCB contamination from polysulphide sealants in residential areas-exposure and risk assessment.

    PubMed

    Priha, Eero; Hellman, Sannamari; Sorvari, Jaana

    2005-04-01

    From the late 1950s to the early 1970s elastic polysulphide sealants were used in outdoor seams between concrete blocks in prefabricated buildings. The sealants contained 5-30% polychlorinated biphenyls (PCBs). Due to the weathering of sealants in general and the replacement of seams with new PCB-free materials in the 1990s, PCBs have drifted to the soil adjacent to buildings. The objectives of this study were to survey PCB contamination in the surroundings of former PCB-containing buildings and to evaluate the risks to human health. Samples from soil, and also from blood serum of residents, were collected to obtain data for exposure assessment. The health risk assessment was based on deterministic and probabilistic calculations for cancer and non-cancer risks. Soil ingestion and dermal contact were considered the main routes of exposure and children the most important exposed group. The mean total PCB concentration was 6.83 mg/kg within 2m of the buildings and 0.52 mg/kg within 3-10 m from of the buildings. The deterministic risk assessment with conservative parameters resulted in lifetime cancer risk estimates on the order of 10(-6)-10(-7). The lifetime average daily dose (LADD) for PCBs was less than 10% of the reference dose (RfD) 0.02 microg/kg day, which is based on immunosupression in monkeys. The LADD corresponding to the total site attributable exposure was less than 10% of the estimated average dietary PCB intake in Finland. Children can, however, in worst cases be exposed to daily doses near the level of the RfD. Low cost measures are recommended to reduce possible exposure of children. PMID:15788176

  15. 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.

  16. TRICARE; Revision of Nonparticipating Providers Reimbursement Rate; Removal of Cost Share for Dental Sealants; TRICARE Dental Program. Final rule.

    PubMed

    2016-03-01

    This final rule revises the benefit payment provision for nonparticipating providers to more closely mirror industry practices by requiring TDP nonparticipating providers to be reimbursed (minus the appropriate cost-share) at the lesser of billed charges or the network maximum allowable charge for similar services in that same locality (region) or state. This rule also updates the regulatory provisions regarding dental sealants to clearly categorize them as a preventive service and, consequently, eliminate the current 20 percent cost-share applicable to sealants to conform with the language in the regulation to the statute. PMID:26964152

  17. Disorganized Cortical Patches Suggest Prenatal Origin of Autism

    MedlinePlus

    ... brain tissue revealed patch-like areas of disorganized neurons. Arrows show a patch of decreased or absent ... autistic brain is speckled with patches of abnormal neurons, according to research partially funded by the National ...

  18. Deformation of vortex patches by boundaries

    NASA Astrophysics Data System (ADS)

    Crosby, A.; Johnson, E. R.; Morrison, P. J.

    2013-02-01

    The deformation of two-dimensional vortex patches in the vicinity of fluid boundaries is investigated. The presence of a boundary causes an initially circular patch of uniform vorticity to deform. Sufficiently far away from the boundary, the deformed shape is well approximated by an ellipse. This leading order elliptical deformation is investigated via the elliptic moment model of Melander, Zabusky, and Styczek [J. Fluid Mech. 167, 95 (1986), 10.1017/S0022112086002744]. When the boundary is straight, the centre of the elliptic patch remains at a constant distance from the boundary, and the motion is integrable. Furthermore, since the straining flow acting on the patch is constant in time, the problem is that of an elliptic vortex patch in constant strain, which was analysed by Kida [J. Phys. Soc. Jpn. 50, 3517 (1981), 10.1143/JPSJ.50.3517]. For more complicated boundary shapes, such as a square corner, the motion is no longer integrable. Instead, there is an adiabatic invariant for the motion. This adiabatic invariant arises due to the separation in times scales between the relatively rapid time scale associated with the rotation of the patch and the slower time scale associated with the self-advection of the patch along the boundary. The interaction of a vortex patch with a circular island is also considered. Without a background flow, the conservation of angular impulse implies that the motion is again integrable. The addition of an irrotational flow past the island can drive the patch towards the boundary, leading to the possibility of large deformations and breakup.

  19. A safe and efficient method to retrieve mesenchymal stem cells from three-dimensional fibrin gels.

    PubMed

    Carrion, Bita; Janson, Isaac A; Kong, Yen P; Putnam, Andrew J

    2014-03-01

    Mesenchymal stem cells (MSCs) display multipotent characteristics that make them ideal for potential therapeutic applications. MSCs are typically cultured as monolayers on tissue culture plastic, but there is increasing evidence suggesting that they may lose their multipotency over time in vitro and eventually cease to retain any resemblance to in vivo resident MSCs. Three-dimensional (3D) culture systems that more closely recapitulate the physiological environment of MSCs and other cell types are increasingly explored for their capacity to support and maintain the cell phenotypes. In much of our own work, we have utilized fibrin, a natural protein-based material that serves as the provisional extracellular matrix during wound healing. Fibrin has proven to be useful in numerous tissue engineering applications and has been used clinically as a hemostatic material. Its rapid self-assembly driven by thrombin-mediated alteration of fibrinogen makes fibrin an attractive 3D substrate, in which cells can adhere, spread, proliferate, and undergo complex morphogenetic programs. However, there is a significant need for simple cost-effective methods to safely retrieve cells encapsulated within fibrin hydrogels to perform additional analyses or use the cells for therapy. Here, we present a safe and efficient protocol for the isolation of MSCs from 3D fibrin gels. The key ingredient of our successful extraction method is nattokinase, a serine protease of the subtilisin family that has a strong fibrinolytic activity. Our data show that MSCs recovered from 3D fibrin gels using nattokinase are not only viable but also retain their proliferative and multilineage potentials. Demonstrated for MSCs, this method can be readily adapted to retrieve any other cell type from 3D fibrin gel constructs for various applications, including expansion, bioassays, and in vivo implantation. PMID:23808842

  20. 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

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

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

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

  2. The influence of type 2 diabetes on fibrin clot properties in patients with coronary artery disease.

    PubMed

    Neergaard-Petersen, S; Hvas, A-M; Kristensen, S D; Grove, E L; Larsen, S B; Phoenix, F; Kurdee, Z; Grant, P J; Ajjan, R A

    2014-12-01

    Type 2 diabetes mellitus (T2DM) increases the risk of coronary thrombosis and both conditions are associated with altered fibrin clot properties. However, the influence of T2DM on fibrin clot properties in patients with coronary artery disease (CAD) remains unclear. We aimed to investigate the influence of T2DM on fibrin clot properties in patients with CAD. Fibrin clot structure and fibrinolysis were investigated in 581 CAD patients (148 with T2DM) using turbidimetric assays, confocal and scanning electron microscopy. Clots made from plasma and plasma-purified fibrinogen were studied, and plasma levels of inflammatory markers were analysed. T2DM patients had increased clot maximum absorbance compared with non-diabetic patients (0.36 ± 0.1 vs 0.33 ± 0.1 au; p=0.01), displayed longer lysis time (804 [618;1002] vs 750 [624;906] seconds; p=0.03) and showed more compact fibrin structure assessed by confocal and electron microscopy. Fibrinogen levels were elevated in T2DM (p< 0.001), but clots made from purified fibrinogen showed no differences in fibrin properties in the two populations. Adjusting for fibrinogen levels, T2DM was associated with C-reactive protein and complement C3 plasma levels, with the former correlating with clot maximum absorbance (r=0.24, p< 0.0001) and the latter with lysis time (r=0.30, p< 0.0001). Independent of fibrinogen levels, females had more compact clots with prolonged lysis time compared with males (all p-values< 0.001). In conclusion, T2DM is associated with prothrombotic changes in fibrin clot properties in patients with CAD. This is related to quantitative rather than qualitative changes in fibrinogen with a possible role for inflammatory proteins. PMID:25187394

  3. Routine patch testing with paraben esters.

    PubMed

    Menné, T; Hjorth, N

    1988-09-01

    Paraben esters are the most widely used preservatives in cosmetics and topical medicaments. Their sensitization potential is low, based on both experimental and human experience. A paraben mixture is included in the ICDRG standard series, and in patch test studies, approximately 1% of eczema patients react to it. The present study confirms this frequency in 8020 patients patch tested consecutively. Testing with the individual paraben esters was employed as confirmation, which makes it unlikely that the excited skin syndrome is a significant problem in this context. It remains undetermined whether the present paraben mixture is the optimal patch test material for diagnosing paraben sensitivity. PMID:3191679

  4. 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.

  5. Koch fractal boundary patch over reactive impedance

    NASA Astrophysics Data System (ADS)

    Reddy V, Venkateshwar; Sarma, N. V. S. N.

    2013-04-01

    This paper describes the enhancement of bandwidth and miniaturization for patch antennas. Introduction of fractal structure (Square Koch) over reactive impedance surface (RIS) is used to enhance impedance bandwidth while minimizing the patch size. Comparison has been made with those of a single-layer (sub1) antenna and the corresponding dual-layer (RIS) antenna. Approximately double the impedance bandwidth is achieved with the proposed RIS Square Koch antenna 1 when compared with Square Koch antenna 1without RIS. There is a 55 % reduction in the patch size. The simulated results indicate that the presented antennas provide gain of about 2.5dBi over the entire band of frequencies.

  6. Sutureless colon anastomosis with fibrin glue in the rat.

    PubMed

    Haukipuro, K A; Hulkko, O A; Alavaikko, M J; Laitinen, S T

    1988-08-01

    The only technique available for creating an intestinal anastomosis without tissue strangulation is gluing. Theoretically, this could lead to a higher hydroxyproline content and greater mechanical strength than in a sutured anastomosis. To test the hypothesis, 83 rats underwent left colon resection and inverted primary anastomosis with either one layer of sutures (NG group) or fibrin glue (FG group). Seven-day FG anastomoses showed less adhesions (P = .02) but one subclinical leakage and a further radiologic one, compared with a greater amount of adhesions but no leakages in the NG group. The mean bursting pressures (mmHg) in the FG and NG groups, respectively, were 25 +/- 20 (SD) and 63 +/- 23 (N.S.) 30 minutes after surgery, 107 +/- 33 and 115 +/- 30 after one day, 81 +/- 31 and 133 +/- 26 (P less than .001) after four days, and 161 +/- 36 and 175 +/- 24 after seven days. The somewhat earlier rise in hydroxyproline content in the glued anastomoses did not lead to significant intergroup differences. The glued anastomoses were thus weak during the critical lag period of healing. Also, by preventing adhesion formation, the glue may reduce the extra blood supply from perianastomotic vessels. The outcomes might have differed more under demanding experimental or clinical situations. PMID:2456902

  7. Ethinyl Estradiol and Norelgestromin Transdermal Patch

    MedlinePlus

    ... contraceptive patch is a very effective method of birth control, but it does not prevent the spread of ... period, you must use a backup method of birth control (such as a condom and/or a spermicide) ...

  8. 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.

  9. An evaluation of patch connectivity measures.

    PubMed

    Prugh, Laura R

    2009-07-01

    Measuring connectivity is critical to the study of fragmented populations. The three most commonly used types of patch connectivity measures differ substantially in how they are calculated, but the performance of these measures has not been broadly assessed. Here I compare the ability of nearest neighbor (NN), buffer, and incidence function model (IFM) measures to predict the patch occupancy and colonization patterns of 24 invertebrate, reptile, and amphibian metapopulations. I predicted that NN measures, which have been criticized as being overly simplistic, would be the worst predictors of species occupancy and colonization. I also predicted that buffer measures, which sum the amount of habitat in a radius surrounding the focal patch, would have intermediate performance, and IFM measures, which take into account the areas and distances to all potential source patches, would perform best. As expected, the simplest NN measure (distance to the nearest habitat patch, NHi) was the poorest predictor of patch occupancy and colonization. Contrary to expectations, however, the next-simplest NN measure (distance to the nearest occupied [source] patch, NSi) was as good a predictor of occupancy and colonization as the best-performing buffer measure and the general IFM measure Si. In contrast to previous studies suggesting that area-based connectivity measures perform better than distance-based ones, my results indicate that the exclusion of vacant habitat patches from calculations is the key to improved measure performance. I highlight several problems with the parameterization and use of IFM measures and suggest that models based on NSi are equally powerful and more practical for many conservation applications. PMID:19688936

  10. Aspects and applications of patched grid calculations

    NASA Technical Reports Server (NTRS)

    Walters, Robert W.; Switzer, George F.; Thomas, James L.

    1991-01-01

    Patched grid calculations within the framework of an implicit, flux vector split upwind/relaxation algorithm for the Euler equations are presented. Aspects of computing on patched grids are discussed including the effect of a metric-discontinuous interface on the convergence rate of the algorithm, and the effect of curvature along an interface. Applications to a converging-diverging nozzle including effects of choking and bypass slots in two dimensions are presented.

  11. 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.

  12. A comparative study of skin cell activities in collagen and fibrin constructs.

    PubMed

    Law, Jia Xian; Musa, Faiza; Ruszymah, Bt Hj Idrus; El Haj, Alicia J; Yang, Ying

    2016-09-01

    Collagen and fibrin are widely used in tissue engineering due to their excellent biocompatibility and bioactivities that support in vivo tissue formation. These two hydrogels naturally present in different wound healing stages with different regulatory effects on cells, and both of them are mechanically weak in the reconstructed hydrogels. We conducted a comparative study by the growth of rat dermal fibroblasts or dermal fibroblasts and epidermal keratinocytes together in collagen and fibrin constructs respectively with and without the reinforcement of electrospun poly(lactic acid) nanofiber mesh. Cell proliferation, gel contraction and elastic modulus of the constructs were measured on the same gels at multiple time points during the 22 day culturing period using multiple non-destructive techniques. The results demonstrated considerably different cellular activities within the two types of constructs. Co-culturing keratinocytes with fibroblasts in the collagen constructs reduced the fibroblast proliferation, collagen contraction and mechanical strength at late culture point regardless of the presence of nanofibers. Co-culturing keratinocytes with fibroblasts in the fibrin constructs promoted fibroblast proliferation but exerted no influence on fibrin contraction and mechanical strength. The presence of nanofibers in the collagen and fibrin constructs played a favorable role on the fibroblast proliferation when keratinocytes were absent. Thus, this study exhibited new evidence of the strong cross-talk between keratinocytes and fibroblasts, which can be used to control fibroblast proliferation and construct contraction. This cross-talk activity is extracellular matrix-dependent in terms of the fibrous network morphology, density and strength. PMID:27349492

  13. Flow and delta-P dictate where thrombin, fibrin, and von Willebrand Factor will be found.

    PubMed

    Diamond, Scott L

    2016-05-01

    Hemostasis occurs in two different topological scenarios: complete severing of a vessel or disruption of the vessel wall. Either to meet the daily rigors of active life or during an acute trauma, hemostasis involves the regulated and self-limiting production of thrombin to stop bleeding. In contrast, arterial and venous thrombosis typically involves the unregulated, intraluminal growth of a clot, in the absence of bleeding. For either hemostasis or thrombosis, the presence of flow and pressure gradients (delta-P, ΔP) dictates when and where thrombin and fibrin are located and in what quantity. For hemostatic clots, fibrin formation helped limit clot growth. We found that γ'-fibrinogen had a role in limiting clot growth via anti-thrombin activity at venous, but not arterial conditions. For hemophilic blood, severe factor deficiency (<1% healthy) led to a defect in both platelet and fibrin deposition under flow. However, moderate deficiency, which is associated with a less severe bleeding phenotype, had normalized platelet function but still lacked fibrin production. We conclude signaling levels of thrombin can be generated during moderate hemophilia to sufficiently activate platelets to achieve primary hemostasis, even if fibrin formation remains defective. Finally, as a clot grows, shear stresses can become sufficiently extreme in diseased arteries to drive von Willebrand Factor self-association into massive fibers, potentially the final burst of clot growth towards full thrombotic occlusion. PMID:27207416

  14. Dynamic behaviors of astrocytes in chemically modified fibrin and collagen hydrogels.

    PubMed

    Seyedhassantehrani, Negar; Li, Yongchao; Yao, Li

    2016-05-16

    Astrocytes play a critical role in supporting the normal physiological function of neurons in the central nervous system (CNS). Astrocyte transplantation can potentially promote axonal regeneration and functional recovery after spinal cord injury (SCI). Fibrin and collagen hydrogels provide growth-permissive substrates and serve as carriers for therapeutic cell transplantation into an injured spinal cord. However, the application of fibrin and collagen hydrogels may be limited due to their relatively rapid degradation rate in vivo. In this study, immature astrocytes isolated from neonatal rats were grown in fibrin hydrogels containing aprotinin and collagen hydrogels crosslinked with poly(ethylene glycol) ether tetrasuccinimidyl glutarate (4S-StarPEG), and the cell behavior in these hydrogels was studied. The cell viability of astrocytes in the hydrogels was tested using the LIVE/DEAD® assay and the AlamarBlue® assay, and this study showed that astrocytes maintained good viability in these hydrogels. The cell migration study showed that astrocytes migrated in the fibrin and collagen hydrogels, and the migration speed is similar in these hydrogels. The crosslinking of collagen hydrogels with 4S-StarPEG did not change the astrocyte migration speed. However, the addition of aprotinin in the fibrin hydrogel inhibited astrocyte migration. The expression of chondroitin sulfate proteoglycan (CSPG), including NG2, neurocan, and versican, by astrocytes grown in the hydrogels was analyzed by quantitative RT-PCR. The expression of NG2, neurocan, and versican by the cells in these hydrogels was not significantly different. PMID:27079938

  15. Fabrication of electrospun poly (lactide-co-glycolide)-fibrin multiscale scaffold for myocardial regeneration in vitro.

    PubMed

    Sreerekha, Perumcherry Raman; Menon, Deepthy; Nair, Shantikumar V; Chennazhi, Krishna Prasad

    2013-04-01

    Myocardial tissue engineering is one of the most promising treatment strategies to restore heart function after a massive heart attack. The biomaterials, cells, and scaffold design play important roles in engineering of heart tissue. In this study, we have developed a fibrin-based multiscale electrospun composite scaffold for myocardial regeneration. Fibrin is the natural wound-healing matrix having angiogenic potential and comprehensively used for tissue engineering applications. It provides a natural environment for cell attachment, migration, and proliferation. Morphological, chemical, and mechanical characterization of the scaffolds was done by scanning electron microscopy, fibrin-specific phosphotungstic acid hematoxylin staining, and mechanical testing. The fiber diameters of fibrin nanofibers range from 50 to 300 nm and that of poly (lactide-co-glycolide) microfibers range from 2 to 4 μm, which mimics the structural hierarchy of native myocardial tissue. Our results indicate that this scaffold enhances the differentiation of mesenchymal stem cells into cardiomyocytes. The cardiac phenotype of the cells was confirmed by the presence of cardiac-specific proteins like α-sarcomeric actinin, troponin, tropomyosin, desmin, and atrial natriuretic peptide Estimation of D-Dimer in the culture supernatant for 2 weeks and analysis of scaffold for 3 weeks of in vitro culture of cardiomyocytes indicated the degradation of fibrin and presence of newly synthesized collagen respectively. Our results demonstrate the promising potential of this scaffold for myocardial tissue engineering applications. PMID:23083104

  16. Effect of Age and Diabetes on the Response of Mesenchymal Progenitor Cells to Fibrin Matrices

    PubMed Central

    Stolzing, A.; Colley, H.; Scutt, A.

    2011-01-01

    Mesenchymal stem cells are showing increasing promise in applications such as tissue engineering and cell therapy. MSC are low in number in bone marrow, and therefore in vitro expansion is often necessary. In vivo, stem cells often reside within a niche acting to protect the cells. These niches are composed of niche cells, stem cells, and extracellular matrix. When blood vessels are damaged, a fibrin clot forms as part of the wound healing response. The clot constitutes a form of stem cell niche as it appears to maintain the stem cell phenotype while supporting MSC proliferation and differentiation during healing. This is particularly appropriate as fibrin is increasingly being suggested as a scaffold meaning that fibrin-based tissue engineering may to some extent recapitulate wound healing. Here, we describe how fibrin modulates the clonogenic capacity of MSC derived from young/old human donors and normal/diabetic rats. Fibrin was prepared using different concentrations to modulate the stiffness of the substrate. MSC were expanded on these scaffolds and analysed. MSC showed an increased self-renewal on soft surfaces. Old and diabetic cells lost the ability to react to these signals and can no longer adapt to the changed environment. PMID:22194749

  17. Fibrin glue as a protective tool for microanastomoses in limb reconstructive surgery

    PubMed Central

    Langer, Stefan; Schildhauer, Thomas A.; Dudda, Marcel; Sauber, Jeannine; Spindler, Nick

    2015-01-01

    Aim: Fibrin glue becomes a more and more routinely used tool for stabilization of microanastomoses and nerve repair. This paper summarizes the technical properties and advantages of its use in a wide variety of microsurgical contexts, and includes an exemplary limb reconstructive case. Patients and methods: A total of 131 patients who had undergone elective and emergency microsurgery mainly of the limbs were retrospectively analyzed, as was the use of free flaps. Results: The use of fibrin glue allows for proper positioning of anastomoses and repaired nerves. No torsion of the pedicle could be seen. The flap survival rated >94%. The fibrin glue could stay in place in >99%. In the rare case of revision, the fibrin glue could easily be removed without damaging the region of the microanastomosis. Conclusion: Fibrin glue should not be used to repair insufficient, i.e., leaking anastomoses, but it does protect the site of anastomosis from tissue and fluid pressure. It prevents the pedickle from torsion and its use facilitates relocation of the microanastomoses in cases of revision surgery. PMID:26759762

  18. Improved Growth Factor Directed Vascularization into Fibrin Constructs Through Inclusion of Additional Extracellular Molecules

    PubMed Central

    Smith, JD; Melhem, ME; Magge, KT; Waggoner, AS; Campbell, PG

    2009-01-01

    Using the chick chorioallantoic membrane assay (CAM) and a novel histological technique we investigated the ability of blood vessels to directly invade fibrin-based scaffolds. In our initial experiments utilizing vascular endothelial growth factor (VEGF165) we found no direct invasion. Instead, the fibrin was completely degraded and replaced with highly vascularized new tissue. Addition of fibroblast growth factor-2 (FGF-2), bone morphogenic protein-2 (BMP-2), or platelet-derived growth factor-BB (PDGF-BB) to the fibrin construct also did not result in construct vascularization. Because natural and regenerating tissues exhibit complex extracellular matrices (ECMs), we hypothesized that a more complex scaffold may improve blood vessel invasion. Addition of fibronectin, hyaluronic acid, and collagen type I within 20 mg/mL fibrin constructs resulted in no significant improvement. However, the same additive concentrations within 10 mg/mL fibrin constructs resulted in dramatic improvements, specifically with hyaluronic acid. Overall, we believe these results indicate the importance of structural and functional cues of not only in the initial scaffold but also as the construct is degraded and remodeled. Furthermore, the CAM assay may represent a useful model for understanding ECM interactions as well as for screening and designing tissue engineered scaffolds. PMID:17223139

  19. 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

  20. Fibrin-Induced Skin Fibrosis in Mice Deficient in Tissue Plasminogen Activator

    PubMed Central

    de Giorgio-Miller, Alexander; Bottoms, Steve; Laurent, Geoffrey; Carmeliet, Peter; Herrick, Sarah

    2005-01-01

    The deposition of fibrin is an integral part of the tissue repair process, but its persistence is also associated with a number of fibrotic conditions. This study addressed the hypothesis that reduced fibrinolysis and fibrin persistence are associated with an enhanced accumulation of collagen and the development of skin fibrosis. Decreased fibrinolysis was confirmed in fibrin gel cultures that contained human dermal fibroblasts plus the specific plasmin inhibitor α2-antiplasmin or dermal fibroblasts isolated from plasminogen activator (PA)-deficient mice. Collagen accumulation was significantly increased in the presence of inhibitor and in tPA-deficient, but not uPA-deficient, fibroblasts compared with controls. These findings were also confirmed using a skin fibrosis model in which multiple injections of fibrin were given subcutaneously to PA-deficient mice. Injection sites from tPA-deficient mice displayed significantly increased collagen levels compared with uPA-deficient mice and wild-type controls. Up-regulation of fibroblast procollagen gene expression and reduced activation of pro-MMP-1 appeared to mediate the increase in collagen by human dermal fibroblasts in the presence of α2-antiplasmin. These findings suggest that persistent fibrin is associated with enhanced collagen accumulation that may result in the development of fibrotic skin disorders in which reduced fibrinolysis is a feature. PMID:16127152

  1. Characterization of Fibrin and Collagen Gels for Engineering Wound Healing Models

    PubMed Central

    Moreno-Arotzena, Oihana; Meier, Johann G.; del Amo, Cristina; García-Aznar, José Manuel

    2015-01-01

    Hydrogels are used for 3D in vitro assays and tissue engineering and regeneration purposes. For a thorough interpretation of this technology, an integral biomechanical characterization of the materials is required. In this work, we characterize the mechanical and functional behavior of two specific hydrogels that play critical roles in wound healing, collagen and fibrin. A coherent and complementary characterization was performed using a generalized and standard composition of each hydrogel and a combination of techniques. Microstructural analysis was performed by scanning electron microscopy and confocal reflection imaging. Permeability was measured using a microfluidic-based experimental set-up, and mechanical responses were analyzed by rheology. We measured a pore size of 2.84 and 1.69 μm for collagen and fibrin, respectively. Correspondingly, the permeability of the gels was 1.00·10−12 and 5.73·10−13 m2. The shear modulus in the linear viscoelastic regime was 15 Pa for collagen and 300 Pa for fibrin. The gels exhibited strain-hardening behavior at ca. 10% and 50% strain for fibrin and collagen, respectively. This consistent biomechanical characterization provides a detailed and robust starting point for different 3D in vitro bioapplications, such as collagen and/or fibrin gels. These features may have major implications for 3D cellular behavior by inducing divergent microenvironmental cues. PMID:26290683

  2. Pericardial patch venoplasty heals via attraction of venous progenitor cells.

    PubMed

    Bai, Hualong; Wang, Mo; Foster, Trenton R; Hu, Haidi; He, Hao; Hashimoto, Takuya; Hanisch, Jesse J; Santana, Jeans M; Xing, Ying; Dardik, Alan

    2016-06-01

    Pericardial patches are commonly used during cardiovascular surgery to close blood vessels. In arteries, patches accumulate arterial progenitor cells; we hypothesized that venous patches would accumulate venous progenitor cells, in the absence of arterial pressure. We developed a novel rat inferior vena cava (IVC) venotomy model and repaired it with a pericardial patch. Cells infiltrated the patch to form a thick neointima by day 7; some cells were CD34(+)/VEGFR2(+) and CD31(+)/Eph-B4(+) consistent with development of venous identity in the healing patch. Compared to arterial patches, the venous patches had increased neointimal thickness at day 7 without any pseudoaneurysms. Addition of an arteriovenous fistula (AVF) to increase blood flow on the patch resulted in reduced patch neointimal thickness and proliferation, but neointimal thickness was not reversible with AVF ligation. These results show that rat patch venoplasty is a novel model of aggressive venous neointimal hyperplasia. PMID:27354544

  3. Formulation and characterization of poloxamine-based hydrogels as tissue sealants.

    PubMed

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

    2012-07-01

    In situ cross linkable 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 various molecular weights and hydrophilic/lipophilic balances 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 2-5weeks, depending on their T1107/T904 composition. In conclusion, select poloxamine-based hydrogels possess a number of properties potentially beneficial to tissue sealant applications, including a substantial increase in viscosity between room/physiological temperatures, resistance to cell adhesion and maintenance of a stable volume during equilibration. PMID:22406506

  4. Synthesis and Properties of a Barium Aluminosilicate Solid Oxide Fuel Cell Glass-Ceramic Sealant

    SciTech Connect

    Meinhardt, Kerry D.; Kim, Dong-Sang; Chou, Y. S.; Weil, K. Scott

    2008-07-15

    A series of barium aluminosilicate glasses modified with CaO and B2O3, were prepared and evaluated with respect to their suitability in sealing planar solid oxide fuel cells (SOFCs). At a target operating temperature of 750ºC, the long-term CTE of one particular composition (35 mol% BaO, 15 mol% CaO, 10 mol% B2O3, 5 mol% Al2O3, bal. SiO2) was found to be particularly stable, due to devitrification to a mixture of glass and ceramic phases. This sealant composition exhibits minimal chemical interaction with the yttria-stabilized zirconia electrolyte, yet forms a strong bond with this material. Interactions with metal components were found to be more extensive and depended on the composition of the metal oxide scale that formed during sealing. Generally alumina-scale formers exhibited a more compact reaction zone with the glass than chromia-scale forming alloys. Mechanical measurements conducted on the bulk glass-ceramic and on seals formed using these materials indicate that the sealant is anticipated to display adequate long-term strength for most conventional stationary SOFC applications.

  5. Occlusal dental caries incidence and implications for sealant programs in a US college student population.

    PubMed

    Stahl, J W; Katz, R V

    1993-01-01

    Given the decline in dental caries incidence in preteens and young teenagers in the United States, a study of the incidence of dental caries in young adults (17-23 years) was conducted to provide a descriptive epidemiologic picture of this "new" natural history of dental caries in the late and post-teenage years. A retrospective study was performed analyzing the detailed dental records of the four-year college experience in the class of 1989, US Coast Guard Academy. Occlusal caries incidence, in the absence of associated proximal caries, was shown to be moderately common in molars (11.9%) and rare in premolars (0.8%). In contrast to previous studies' findings, demographic indicators, socioeconomic status indicators, and prior caries experience were poor predictors of occlusal caries incidence; targeting a universal sealant policy in this population therefore would be done best by tooth type rather than patient type. A preliminary cost-comparison model, projected over a 40-month period, suggests that the cost of initiating a universal molar sealant policy in this population would be 92 cents per year per student greater than the cost of restoring occlusal caries in the presence of sound proximal surfaces. This cost comparison suggests that it would be advantageous to initiate such a policy. PMID:8258782

  6. 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. PMID:25268042

  7. Effect of three surface sealants on marginal sealing of Class V composite resin restorations.

    PubMed

    Ramos, R P; Chimello, D T; Chinelatti, M A; Dibb, R G; Mondelli, J

    2000-01-01

    This study evaluated in vitro the effectiveness of three different surface sealants (Fortify, Protect-it! and Optiguard) on the marginal sealing of Class V light-activated composite resin restorations (Prodigy). For this purpose, 20 sound noncarious human premolars extracted within a six-month period were selected. Class V cavities with the occlusal margin in enamel and cervical margin in cementum were prepared in both buccal and lingual surfaces. The teeth, randomly assigned in four groups with 10 cavities in each group, were restored with composite resin after applying an adhesive system (Optibond FL). After the finishing and polishing procedures, the restorations were covered with a specific surface sealant, except for the control samples, which were not sealed. After placing restorations, the specimens were thermocycled and immersed in a 50% silver nitrate solution (tracer agent) for eight hours, sectioned longitudinally and analyzed for leakage using an optical microscope in a blind study with three examiners. The marginal microleakage was evaluated at the occlusal and cervical interfaces and compared among the four groups using the Kruskall-Wallis and the Wilcoxon Tests. There was better sealing at the occlusal margin, and in this region, there were no statistically significant differences among the materials (p > 0.05). In the cervical region, Fortify and Protect-it! showed improved results over the Control Group, and Optiguard showed similar results to the Control Group (without sealing). PMID:11203855

  8. Synthesis and properties of a barium aluminosilicate solid oxide fuel cell glass-ceramic sealant

    NASA Astrophysics Data System (ADS)

    Meinhardt, K. D.; Kim, D.-S.; Chou, Y.-S.; Weil, K. S.

    A series of barium aluminosilicate glasses modified with CaO and B 2O 3 were prepared and evaluated with respect to their suitability in sealing planar solid oxide fuel cells (SOFCs). At a target operating temperature of 750 °C, the long-term coefficient of thermal expansion (CTE) of one particular composition (35 mol% BaO, 15 mol% CaO, 10 mol% B 2O 3, 5 mol% Al 2O 3, and bal. SiO 2) was found to be particularly stable, due to devitrification to a mixture of glass and ceramic phases. This sealant composition exhibits minimal chemical interaction with the yttria-stabilized zirconia electrolyte, yet forms a strong bond with this material. Interactions with metal components were found to be more extensive and depended on the composition of the metal oxide scale that formed during sealing. Generally alumina-scale formers exhibited a more compact reaction zone with the glass than chromia-scale forming alloys. Mechanical measurements conducted on the bulk glass-ceramic and on seals formed using these materials indicate that the sealant is anticipated to display adequate long-term strength for most conventional stationary SOFC applications.

  9. Pulse Dynamics in Endocytic Protein Patches

    NASA Astrophysics Data System (ADS)

    Carlsson, Anders; Wang, Xinxin

    2015-03-01

    During the process of endocytosis in yeast, submicron-sized protein patches assemble, exert forces on the membrane to bend it, and finally disassemble. The patches contain an initial coat that establishes the endocytic site and binds cargo, polymers of the protein actin, ``nucleation-promoting factors'' (NPFs) that catalyze actin polymerization, and curvature-generating proteins. We model the dynamics of protein patches in yeast using a variant of the activator-inhibitor ``Fitzhugh-Nagumo'' model. We treat NPFs as the activator, and polymerized actin as the inhibitor, on the basis of findings that the lifetime of NPF patches is extended when actin polymerization is inhibited. Using this model, we find that as the polymerization rate is reduced, there is a discontinuous transition from protein pulses to persistent patches. We also find, surprisingly, that in some parameter regimes reducing the polymerization rate can increase the polymerized-actin content of the patch. We present data for NPF dynamics budding yeast, which confirm some of the predictions of the model. Supported by NIH under Grant R01-GM107667.

  10. Montage of Apollo Crew Patches

    NASA Technical Reports Server (NTRS)

    1979-01-01

    This montage depicts the flight crew patches for the manned Apollo 7 thru Apollo 17 missions. The Apollo 7 through 10 missions were basically manned test flights that paved the way for lunar landing missions. Primary objectives met included the demonstration of the Command Service Module (CSM) crew performance; crew/space vehicle/mission support facilities performance and testing during a manned CSM mission; CSM rendezvous capability; translunar injection demonstration; the first manned Apollo docking, the first Apollo Extra Vehicular Activity (EVA), performance of the first manned flight of the lunar module (LM); the CSM-LM docking in translunar trajectory, LM undocking in lunar orbit, LM staging in lunar orbit, and manned LM-CSM docking in lunar orbit. Apollo 11 through 17 were lunar landing missions with the exception of Apollo 13 which was forced to circle the moon without landing due to an onboard explosion. The craft was,however, able to return to Earth safely. Apollo 11 was the first manned lunar landing mission and performed the first lunar surface EVA. Landing site was the Sea of Tranquility. A message for mankind was delivered, the U.S. flag was planted, experiments were set up and 47 pounds of lunar surface material was collected for analysis back on Earth. Apollo 12, the 2nd manned lunar landing mission landed in the Ocean of Storms and retrieved parts of the unmanned Surveyor 3, which had landed on the Moon in April 1967. The Apollo Lunar Surface Experiments Package (ALSEP) was deployed, and 75 pounds of lunar material was gathered. Apollo 14, the 3rd lunar landing mission landed in Fra Mauro. ALSEP and other instruments were deployed, and 94 pounds of lunar materials were gathered, using a hand cart for first time to transport rocks. Apollo 15, the 4th lunar landing mission landed in the Hadley-Apennine region. With the first use of the Lunar Roving Vehicle (LRV), the crew was bale to gather 169 pounds of lunar material. Apollo 16, the 5th lunar

  11. 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

  12. Cost-Effectiveness of Pit-and-Fissure Sealants on Primary Molars in Medicaid-Enrolled Children

    PubMed Central

    van der Goes, David N.; Ney, John P.

    2014-01-01

    Objectives. We compared the incremental cost-effectiveness of 2 primary molar sealant strategies—always seal and never seal—with standard care for Medicaid-enrolled children. Methods. We used Iowa Medicaid claims data (2008–2011), developed a tooth-level Markov model for 10 000 teeth, and compared costs, treatment avoided, and incremental cost per treatment avoided for the 2 sealant strategies with standard care. Results. In 10 000 simulated teeth, standard care cost $214 510, always seal cost $232 141, and never seal cost $186 010. Relative to standard care, always seal reduced the number of restorations to 340 from 2389, whereas never seal increased restorations to 2853. Compared with standard care, always seal cost $8.12 per restoration avoided (95% confidence interval [CI] = $4.10, $12.26; P ≤ .001). Compared with never seal, standard care cost $65.62 per restoration avoided (95% CI = $52.99, $78.26; P ≤ .001). Conclusions. Relative to standard care, always sealing primary molars is more costly but reduces subsequent dental treatment. Never sealing costs less but leads to more treatment. State Medicaid programs that do not currently reimburse dentists for primary molar sealants should consider reimbursement for primary molar sealant procedures as a population-based strategy to prevent tooth decay and reduce later treatment needs in vulnerable young children. PMID:24432941

  13. Creep Behavior of Glass/Ceramic Sealant and its Effect on Long-term Performance of Solid Oxide Fuel Cells

    SciTech Connect

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

    2009-10-14

    The creep behavior of glass or glass-ceramic sealant materials used in solid oxide fuel cells (SOFCs) becomes relevant under SOFC operating temperatures. In this paper, the creep of glass-ceramic sealants was experimentally examined, and a standard linear solid model was applied to capture the creep behavior of glass ceramic sealant materials developed for planar SOFCs at high temperatures. The parameters of this model were determined based on the creep test results. Furthermore, the creep model was incorporated into finite-element software programs SOFC-MP and Mentat-FC developed at Pacific Northwest National Laboratory for multi-physics simulation of SOFCs. The effect of creep of glass ceramic sealant materials on the long-term performance of SOFC stacks was investigated by studying the stability of the flow channels and the stress redistribution in the glass seal and on the various interfaces of the glass seal with other layers. Finite element analyses were performed to quantify the stresses in various parts. The stresses in glass seals were released because of creep behavior during operations.

  14. 40 CFR 63.6000 - How do I conduct tests and procedures for puncture sealant application affected sources?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... that satisfies EPA Method 204 (found in 40 CFR part 51, appendix M) criteria, assume 100 percent capture efficiency for variable F. Equation 1 follows: ER09JY02.008 Where: R=overall control system... used at your puncture sealant application affected source, use EPA Method 311 of appendix A of 40...

  15. 40 CFR 63.6000 - How do I conduct tests and procedures for puncture sealant application affected sources?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... that satisfies EPA Method 204 (found in 40 CFR part 51, appendix M) criteria, assume 100 percent capture efficiency for variable F. Equation 1 follows: ER09JY02.008 Where: R=overall control system... used at your puncture sealant application affected source, use EPA Method 311 of appendix A of 40...

  16. 40 CFR 63.6000 - How do I conduct tests and procedures for puncture sealant application affected sources?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... satisfies EPA Method 204 (found in 40 CFR part 51, appendix M) criteria, assume 100 percent capture... puncture sealant application affected source, use EPA Method 311 of appendix A of 40 CFR part 63, an..., percent. F=capture efficiency of the capture system on add-on control device, percent, determined...

  17. 40 CFR 63.6000 - How do I conduct tests and procedures for puncture sealant application affected sources?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... that satisfies EPA Method 204 (found in 40 CFR part 51, appendix M) criteria, assume 100 percent capture efficiency for variable F. Equation 1 follows: ER09JY02.008 Where: R=overall control system... used at your puncture sealant application affected source, use EPA Method 311 of appendix A of 40...

  18. 40 CFR 63.6000 - How do I conduct tests and procedures for puncture sealant application affected sources?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... satisfies EPA Method 204 (found in 40 CFR part 51, appendix M) criteria, assume 100 percent capture... puncture sealant application affected source, use EPA Method 311 of appendix A of 40 CFR part 63, an..., percent. F=capture efficiency of the capture system on add-on control device, percent, determined...

  19. 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. PMID:27341770

  20. TissuePatch™ as a novel synthetic sealant for repair of superficial lung defect: in vitro tests results

    PubMed Central

    2012-01-01

    Background Controversies surrounding the efficacy of surgical sealants against alveolar air leaks (AAL) in lung surgery abound in the literature. We sought to test the sealing efficacy of a novel synthetic sealant, TissuePatch™ in an in vitro lung model. Methods The lower lobe of freshly excised swine lung (n = 10) was intubated and ventilated. A superficial parenchymal defect (40 × 25 mm) was created, followed by AAL assessment. After sealant application, AAL was assessed again until burst failure occurred. The length of defect was recorded to evaluate the elasticity of the sealant. Results Superficial parenchymal defects resulted in AAL increasing disproportionally with ascending maximal inspiratory pressure (Pmax). Multiple linear regression analysis revealed strong correlation between AAL and Pmax, compliance, resistance. After sealant application, AAL was sealed in all ten tests at an inspired tidal volume (TVi) of 400 ml, in nine tests at TVi = 500 ml, in seven at TVi = 600 ml and in five at TVi = 700 ml. The mean burst pressure was 42 ± 9 mBar. Adhesive and cohesive sealant failures were found in six and three tests respectively. The length of defect before sealant failure was 8.9 ± 4.9% larger than that at TVi = 400 ml, demonstrating an adequate elasticity of this sealant film. Conclusions TissuePatch™ may be a reliable sealant for alternative or adjunctive treatment for repair of superficial parenchymal defects in lung surgery. The clinical benefits of this sealant should be confirmed by prospective, randomised controlled clinical trials. Abstrakt Hintergrund Die Wirksamkeit von chirurgischen Klebstoffen zur Prävention von alveolo-pleuralem Luftleck (APL) ist trotz zunehmenden klinischen Anwendungen in Lungenchirurgie immer noch kontrovers diskutiert. Wir evaluierten die Abdichtungswirksamkeit von einem neuartigen synthetischen Kleber, TissuePatch™ mittels eines in vitro Lungenmodels. Methode Der Unterlappen von

  1. A new technique using fibrin glue in the management of auricular hematoma.

    PubMed

    Mohamad, Shwan H; Barnes, Martyn; Jones, Stephen; Mahendran, Suresh

    2014-11-01

    : This study aims to describe a new technique for the management of auricular hematoma using fibrin glue. Five difficult cases of auricular hematoma were managed using this technique, including 2 recurrent and 3 delayed presentations. After skin preparation and local anesthetic, an incision was made, the hematoma was evacuated, and the cavity was washed out with saline. Fibrin glue was applied liberally; a dental roll pressure dressing was applied and secured with a prolene bead suture. The patients were given a course of oral antibiotic and reviewed after 5 days for removal of the external dressing. They were later assessed to exclude re-accumulation of the hematoma. All patients had complete resolution of the hematoma without re-accumulation; they were satisfied with the cosmetic results and experienced no complications. This case series provides evidence that fibrin glue is effective in the management of auricular hematoma. Larger studies may provide further evidence of the effectiveness of this new technique. PMID:24699189

  2. Physicomechanical and antibacterial properties of experimental resin-based dental sealants modified with nylon-6 and chitosan nanofibers.

    PubMed

    Hamilton, María F; Otte, Andrew D; Gregory, Richard L; Pinal, Rodolfo; Ferreira-Zandoná, Andrea; Bottino, Marco C

    2015-11-01

    This study aimed to develop and evaluate resin-based experimental dental sealants containing electrospun nylon-6 (N6) and chitosan (CH) fibers in an attempt to improve the physicomechanical properties and provide an antibacterial protective effect, respectively. Electrospun N6 and CH mats were immersed into a resin mixture, light-cured, and then cryomilled to obtain micron-sized resin-modified fiber particles. Different levels of the novel cryomilled particles (i.e. 1, 2.5, and 5% relative to the resin mixture, % by weight) were used to prepare the N6- and CH-containing sealants. A commercial sealant and the experimental resin mixture (unfilled) were used as controls. Flexural strength (FS), Vickers microhardness (VH), and agar diffusion tests were performed. The data were analyzed at the 5% significance level. No significant difference in fiber diameter of N6 (503 ± 31 nm) and CH (595 ± 38 nm) was observed. Upon cryomilling, the resin-modified CH and N6 mats led to the formation of irregularly-shaped particles, with an average diameter of 14.24 µm and 15.87 µm, respectively. CH-5% had significantly higher FS (115.3 ± 1.3 MPa) than all the other groups. CH-1% had significantly higher hardness values (38.3 ± 0.3 VHN) than all the other groups. Collectively, the results indicated that CH-containing sealants presented the highest FS and hardness; however, none of the CH-containing sealants displayed antimicrobial properties. PMID:25532852

  3. 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

  4. Knowledge, value, opinion and practice about usage of pit and fissure sealant among dental professionals in Chennai, Tamil Nadu, India

    PubMed Central

    Nagappan, N.; Dhamodhar, M. Dinesh; Nithin, M. G.; Kumar, E. Senthil

    2015-01-01

    Aim: A study was aimed to assess the knowledge, value, opinion, and practice regarding the use of dental sealants among private dental practitioners in Chennai, Tamil Nadu, India. Materials and Methods: A self-administrated questionnaire were distributed to 192 private dental practitioners in Chennai, Tamil Nadu, India by using simple random sampling. A convenience sampling technique was employed. The questionnaire consisted of 28 items, which included information about knowledge, value, opinion, and practice regarding dental sealants. The questionnaire was obtained from the study by San Martin et al. 2013 and Kailash Asawa et al. 2014. Frequency distribution was tabulated. For frequency distribution strongly, strongly agree, and agree were combined as “agree” and strongly disagree and disagree were combined as “disagree.” There were no changes in “neutral.” Results: Among the 196 study subjects 56.2% were males and 43.8% were females with their clinical experience of 52.1% for <5 years, 35.4% for 5–10 years, and 13.5% for >15 years. The mean scores for knowledge, value, opinion, and practice were 41.8 ± 3.7, 18.7 ± 2.8, 18.1 ± 1.4, and 12.9 ± 2.3, respectively. Conclusion: The results suggest that dental practitioners had satisfactory knowledge about pit and fissure sealant and had neutral attitudes about sealants being effective. Dental practitioners adequately used the pit and fissure sealants but they did not follow the standardized procedures and specific guidelines. PMID:26942116

  5. 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

  6. 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.

  7. C-reactive protein and fibrin clot strength measured by thrombelastography after coronary stenting

    PubMed Central

    Kreutz, Rolf P.; Owens, Janelle; Breall, Jeffrey A.; Lu, Deshun; von der Lohe, Elisabeth; Bolad, Islam; Sinha, Anjan; Flockhart, David A.

    2014-01-01

    Inflammation is implicated in the progression of coronary artery disease and the molecular processes of inflammation and thrombosis are closely intertwined. Elevated levels of C-reactive protein (CRP) have been associated with an elevated risk of adverse ischaemic events after coronary stenting and hypercoagulability. Heightened whole blood clot strength measured by thrombelastography (TEG) has been associated with adverse ischaemic events after stenting. We intended to examine the relationship of CRP to plasma fibrin clot strength in patients after coronary stenting. Plasma fibrin clot strength was measured by TEG in 54 patients 16–24 h after undergoing elective percutaneous coronary intervention (PCI). Coagulation was induced in citrated plasma by addition of kaolin and CaCl2. Plasma levels of CRP and fibrinogen were measured by enzyme-linked immunoassay. Increasing quartiles of CRP were associated with increasing levels of maximal plasma fibrin clot strength measured by TEG (P < 0.001) and increasing BMI (P =0.04). Patients in the highest quartile of CRP had significantly higher maximal fibrin clot strength (G) than the patients in the lowest quartile (G: 3438 ± 623 vs. 2184 ± 576 dyn/cm2, P < 0.0001). Fibrinogen concentration was not significantly different across quartiles of CRP (P =0.97). Patients with established coronary artery disease undergoing coronary stenting who have elevated CRP after PCI exhibit heightened maximal plasma fibrin clot strength as compared with those with low CRP. Thrombotic risk associated with elevated CRP may be linked to procoagulant changes and high tensile fibrin clot strength independent of fibrinogen concentration. PMID:23429252

  8. C-reactive protein and fibrin clot strength measured by thrombelastography after coronary stenting.

    PubMed

    Kreutz, Rolf P; Owens, Janelle; Breall, Jeffrey A; Lu, Deshun; von der Lohe, Elisabeth; Bolad, Islam; Sinha, Anjan; Flockhart, David A

    2013-04-01

    Inflammation is implicated in the progression of coronary artery disease and the molecular processes of inflammation and thrombosis are closely intertwined. Elevated levels of C-reactive protein (CRP) have been associated with an elevated risk of adverse ischaemic events after coronary stenting and hypercoagulability. Heightened whole blood clot strength measured by thrombelastography (TEG) has been associated with adverse ischaemic events after stenting. We intended to examine the relationship of CRP to plasma fibrin clot strength in patients after coronary stenting. Plasma fibrin clot strength was measured by TEG in 54 patients 16-24 h after undergoing elective percutaneous coronary intervention (PCI). Coagulation was induced in citrated plasma by addition of kaolin and CaCl2. Plasma levels of CRP and fibrinogen were measured by enzyme-linked immunoassay. Increasing quartiles of CRP were associated with increasing levels of maximal plasma fibrin clot strength measured by TEG (P < 0.001) and increasing BMI (P = 0.04). Patients in the highest quartile of CRP had significantly higher maximal fibrin clot strength (G) than the patients in the lowest quartile (G: 3438 ± 623 vs. 2184 ± 576 dyn/cm, P < 0.0001). Fibrinogen concentration was not significantly different across quartiles of CRP (P = 0.97). Patients with established coronary artery disease undergoing coronary stenting who have elevated CRP after PCI exhibit heightened maximal plasma fibrin clot strength as compared with those with low CRP. Thrombotic risk associated with elevated CRP may be linked to procoagulant changes and high tensile fibrin clot strength independent of fibrinogen concentration. PMID:23429252

  9. 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.

  10. 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

  11. Hemostasis of solid viscus trauma by intraparenchymal injection of fibrin glue.

    PubMed

    Hauser, C J

    1989-03-01

    Fibrin glue (FG) is an effective hemostatic agent applied topically to the spleen. In this study, FG was found to be an effective hemostatic agent when applied topically in standardized wounds of the canine liver, spleen, and pancreas. It was markedly more effective, however, when injected intraparenchymally. In a case of severe blunt trauma in a patient with acute alcoholic hepatitis, intraparenchymal FG was lifesaving. Fibrin glue is a useful adjunct in the management of trauma to all the abdominal solid viscera. Intraparenchymal injection is the preferred mode of FG application. PMID:2465750

  12. 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.'.

  13. Plasma fibrin clot phenotype independently affects intracoronary thrombus ultrastructure in patients with acute myocardial infarction.

    PubMed

    Zalewski, Jaroslaw; Bogaert, Jan; Sadowski, Marcin; Woznicka, Olga; Doulaptsis, Konstantinos; Ntoumpanaki, Maria; Ząbczyk, Michal; Nessler, Jadwiga; Undas, Anetta

    2015-06-01

    Determinants of intracoronary thrombus (ICT) composition in patients with ST-elevation myocardial infarction (STEMI) are largely unknown. We sought to investigate whether plasma fibrin phenotype and platelet reactivity affect ICT ultrastructure. We assessed the content of fibrin, platelets and erythrocytes including polyhedrocytes by scanning electron microscopy on the surface and inside ICT aspirated from 80 STEMI patients within 12 hours since chest pain onset. Plasma fibrin clot permeability (Ks), which indicates the average pore size, lysis time (t50 %), platelet reactivity index (PRI) and ADP-induced platelet aggregation (ADP5, 20µM) were evaluated on admission. All patients received aspirin and 45 (56.3 %) 600 mg of clopidogrel, 80 (60-120) min prior to aspiration. Higher content of fibrin (61.6 vs 34.3 %, P< 0.0001) and platelets (8.2 vs 4.8 %, P=0.018) and lower erythrocyte content (15.8 vs 42.9 %, P< 0.0001) were found on ICT surface compared with its inner part. After adjustment for fibrinogen, in both ICT parts fibrin content was correlated with Ks (r≤-0.55, P< 0.0001) and t50 % (r≥ 0.29, P≤ 0.02) but not with PRI and ADP5,20µM. Polyhedrocytes were observed in 16 (20 %) patients and their large amount expressed as ≥ 50 % fields of view covered by polyhedrocytes was associated with the lower PRI values (40 vs 69 %, P=0.015), but not Ks or t50 %. By multivariate regression, Ks (β=-0.62, P< 0.0001), clopidogrel pretreatment (β=-0.36, P< 0.001), ischemia time (β=0.19, P=0.044) and family history (β=0.18, P=0.049) independently predicted fibrin content in the whole ICT (R²=0.65, P< 0.0001). Formation of denser plasma fibrin clots is independently associated with high fibrin content within the ICT in STEMI. PMID:25739375

  14. A Novel Virus-Patch Dynamic Model.

    PubMed

    Yang, Lu-Xing; Yang, Xiaofan

    2015-01-01

    The distributed patch dissemination strategies are a promising alternative to the conventional centralized patch dissemination strategies. This paper aims to establish a theoretical framework for evaluating the effectiveness of distributed patch dissemination mechanism. Assuming that the Internet offers P2P service for every pair of nodes on the network, a dynamic model capturing both the virus propagation mechanism and the distributed patch dissemination mechanism is proposed. This model takes into account the infected removable storage media and hence captures the interaction of patches with viruses better than the original SIPS model. Surprisingly, the proposed model exhibits much simpler dynamic properties than the original SIPS model. Specifically, our model admits only two potential (viral) equilibria and undergoes a fold bifurcation. The global stabilities of the two equilibria are determined. Consequently, the dynamical properties of the proposed model are fully understood. Furthermore, it is found that reducing the probability per unit time of disconnecting a node from the Internet benefits the containment of electronic viruses. PMID:26368556

  15. A Novel Virus-Patch Dynamic Model

    PubMed Central

    Yang, Lu-Xing; Yang, Xiaofan

    2015-01-01

    The distributed patch dissemination strategies are a promising alternative to the conventional centralized patch dissemination strategies. This paper aims to establish a theoretical framework for evaluating the effectiveness of distributed patch dissemination mechanism. Assuming that the Internet offers P2P service for every pair of nodes on the network, a dynamic model capturing both the virus propagation mechanism and the distributed patch dissemination mechanism is proposed. This model takes into account the infected removable storage media and hence captures the interaction of patches with viruses better than the original SIPS model. Surprisingly, the proposed model exhibits much simpler dynamic properties than the original SIPS model. Specifically, our model admits only two potential (viral) equilibria and undergoes a fold bifurcation. The global stabilities of the two equilibria are determined. Consequently, the dynamical properties of the proposed model are fully understood. Furthermore, it is found that reducing the probability per unit time of disconnecting a node from the Internet benefits the containment of electronic viruses. PMID:26368556

  16. Patch-primitive driven compressive ghost imaging.

    PubMed

    Hu, Xuemei; Suo, Jinli; Yue, Tao; Bian, Liheng; Dai, Qionghai

    2015-05-01

    Ghost imaging has rapidly developed for about two decades and attracted wide attention from different research fields. However, the practical applications of ghost imaging are still largely limited, by its low reconstruction quality and large required measurements. Inspired by the fact that the natural image patches usually exhibit simple structures, and these structures share common primitives, we propose a patch-primitive driven reconstruction approach to raise the quality of ghost imaging. Specifically, we resort to a statistical learning strategy by representing each image patch with sparse coefficients upon an over-complete dictionary. The dictionary is composed of various primitives learned from a large number of image patches from a natural image database. By introducing a linear mapping between non-overlapping image patches and the whole image, we incorporate the above local prior into the convex optimization framework of compressive ghost imaging. Experiments demonstrate that our method could obtain better reconstruction from the same amount of measurements, and thus reduce the number of requisite measurements for achieving satisfying imaging quality. PMID:25969205

  17. 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/. PMID:22806945

  18. Fault-patch stress-transfer efficiency in presence of sub-patch geometric complexity

    NASA Astrophysics Data System (ADS)

    Zielke, Olaf; Mai, Martin

    2015-04-01

    It is well known that faults are not planar surfaces. Instead they exhibit self-similar or self-affine properties that span a wide range of spatial (sub-micrometer to tens-of-kilometer). This geometric fault roughness has a distinct impact on amount and distribution of stresses/strains induced in the medium and on other portions of the fault. However, when numerically simulated (for example in multi-cycle EQ rupture simulations or Coulomb failure stress calculations) this roughness is largely ignored: individual fault patches --the incremental elements that build the fault surface in the respective computer models-- are planar and fault roughness at this and lower spatial scales is not considered. As a result, the fault-patch stress-transfer efficiency may be systematically too large in those numerical simulations with respect to the "actual" efficiency level. Here, we investigate the effect of sub-patch geometric complexity on fault-patch stress-transfer efficiency. For that, we sub-divide a fault patch (e.g., 1x1km) into a large number of sub-patches (e.g., 20x20m) and determine amount of induced stresses at selected positions around that patch for different levels and realizations of fault roughness. For each fault roughness level, we compute mean and standard deviation of the induced stresses, enabling us to compute the coefficient of variation. We normalize those values with stresses from the corresponding single (planar) fault patch, providing scaling factors and their variability for stress transfer efficiency. Given a certain fault roughness that is assumed for a fault, this work provides the means to implement the sub-patch fault roughness into investigations based on fault-patch interaction schemes.

  19. 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.

  20. Assessment of the inhibitory effects of fissure sealants on the demineralization of primary teeth using an automatic pH-cycling system.

    PubMed

    Ushimura, Shuya; Nakamura, Koichi; Matsuda, Yasuhiro; Minamikawa, Hajime; Abe, Shigeaki; Yawaka, Yasutaka

    2016-01-01

    In this study, we examined the effects of fissure sealants on inhibition of demineralization of primary teeth using an automatic pHcycling system. Three fissure sealants were used: Teethmate F-1 2.0 (TM), BeautiSealant (BS), and Fuji III LC (IIILC). Using an automatic pH-cycling system, the specimens (n=12) were repeatedly demineralized and remineralized. Specimens were subjected to transverse microradiography (TMR), and changes in integrated mineral loss (IML) and lesion depth (Ld), indicated as ΔIML and ΔLd, respectively, were calculated. In addition, fluoride levels in the enamel were assessed using microparticle-induced gammaray emission/particle-induced X-ray emission (n=3). IIILC showed the lowest values for ΔIML and ΔLd, followed by BS and then TM. The highest amount of fluorine in the enamel was observed for IIILC, followed by TM and BS. All fissure sealants inhibited demineralization in primary teeth. PMID:27041023

  1. 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

  2. Comparative acceptance of three transdermal nitroglycerin placebo patches.

    PubMed

    Rayment, C M; Kaul, A F; Garfield, J M

    1985-06-01

    Factors that might affect patient acceptance of transdermal drug-delivery system patches were evaluated in healthy volunteers using placebo patches. Placebo transdermal nitroglycerin patches (Transderm-Nitro 5 placebo, Ciba Pharmaceutical Company; Nitro-Dur 10 cm2 placebo, Key Pharmaceuticals; and Nitrodisc 5 placebo, Searle Laboratories) were supplied by the manufacturers. Eighty-two healthy subjects were randomly assigned to begin using one of the three brands of patches. Using a Latin-square crossover design, subjects applied each brand of patch daily for five days and crossed over to the other brands on study days 6 and 11. At the end of each study phase, subjects completed a written questionnaire designed to evaluate their overall acceptance of each brand of patch. A total of 80 subjects completed all three phases of the study. According to forced rank preference, 84% of subjects preferred the Ciba patch to one of the other two brands. Subjects judged the Ciba patch to be the easiest of the three brands to use and reported significantly fewer side effects and skin irritation while using the Ciba patch; they also preferred the size of the Ciba patch and experienced significantly fewer problems with adherence of the Ciba patch. A significant percentage of subjects indicated that they would prefer a transdermal patch over tablets or ointment. Most subjects preferred the Ciba patch over the Key patch or Searle patch. PMID:3925770

  3. Dimensionality reduction via locally reconstructive patch alignment

    NASA Astrophysics Data System (ADS)

    Chen, Yi; Yin, Jun; Zhu, Jie; Jin, Zhong

    2012-07-01

    Based on the local patch concept, we proposed locally reconstructive patch alignment (LRPA) for dimensionality reduction. For each patch, LRPA aims to find the low-dimensional subspace in which the reconstruction error of the within-class nearest neighbors is minimized and the reconstruction error of the between-class nearest neighbors is maximized. LRPA preserves the local structure hidden in the high-dimensional space. More importantly, LRPA has natural connections with linear regression classification (LRC). While LRC uses reconstruction errors as the classification rule, a sample can be classified correctly when the within-class reconstruction error is minimal. The goal of LRPA makes it cooperate well with LRC. The experimental results on the extended Yale B (YALE-B), AR, PolyU finger knuckle print, and the palm print databases demonstrate LRPA plus LRC is an effective and robust pattern-recognition system.

  4. Easier patch testing with TRUE Test.

    PubMed

    Fischer, T; Maibach, H I

    1989-03-01

    TRUE Test, a standardized, ready-to-apply patch test system, is made from polyester covered with a film of allergens incorporated in a hydrophilic polymer. The patches are mounted on nonwoven cellulose tape with acrylic adhesive, covered with siliconized plastic, and packed in an air-tight and light-impermeable envelope. When the test strip is taped on the skin, perspiration hydrates the film and transforms it to a gel, which causes the allergen to be released. The first panel of 12 allergens and allergen mixes is standardized and tested for stability in vitro and in vivo. The accuracy of the test panel has been certified in international multicenter studies by comparing it with present patch test techniques. A second panel of 11 more allergens was completed in 1988. The two test panels include the full standard panel of the North American Contact Dermatitis Group. PMID:2918115

  5. Patch-Clamp Fluorometry: Electrophysiology meets Fluorescence

    PubMed Central

    Kusch, Jana; Zifarelli, Giovanni

    2014-01-01

    Ion channels and transporters are membrane proteins whose functions are driven by conformational changes. Classical biophysical techniques provide insight into either the structure or the function of these proteins, but a full understanding of their behavior requires a correlation of both these aspects in time. Patch-clamp and voltage-clamp fluorometry combine spectroscopic and electrophysiological techniques to simultaneously detect conformational changes and ionic currents across the membrane. Since its introduction, patch-clamp fluorometry has been responsible for invaluable advances in our knowledge of ion channel biophysics. Over the years, the technique has been applied to many different ion channel families to address several biophysical questions with a variety of spectroscopic approaches and electrophysiological configurations. This review illustrates the strength and the flexibility of patch-clamp fluorometry, demonstrating its potential as a tool for future research. PMID:24655500

  6. Boolean Operations with Prism Algebraic Patches.

    PubMed

    Bajaj, Chandrajit; Paoluzzi, Alberto; Portuesi, Simone; Lei, Na; Zhao, Wenqi

    2008-01-01

    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 C(1)-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

  7. 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.

  8. 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.

  9. A comparative investigation of mussel-mimetic sealants for fetal membrane repair.

    PubMed

    Perrini, Michela; Barrett, Devin; Ochsenbein-Koelble, Nicole; Zimmermann, Roland; Messersmith, Phillip; Ehrbar, Martin

    2016-05-01

    Towards the prevention of iatrogenic preterm premature rupture of the fetal membrane, two mussel-mimetic tissue adhesives (cT and cPEG) have been compared and qualified as possible sealants for membrane repair. Monotonic and cyclic inflation tests of repaired fetal membranes were carried out in order to investigate the performance of the glues under quasi-static, fast, and repeated loading. Finite element simulations of repaired and inflated synthetic membranes allowed to compare cT and cPEG under large deformations. Both adhesives seal the membrane well, resisting pressures higher than the intra-uterine baseline. Only under repeated mechanical load, as well as under fast and acute deformation of the membrane, the sealing performance has deteriorated. Even though cT loses adhesion to the deformed membrane, it is able to withstand high deformations and pressures without rupturing, while cPEG breaks. PMID:26255212

  10. 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.

  11. Patch testing with cement containing iron sulfate.

    PubMed

    Bruze, M; Fregert, S; Gruvberger, B

    1990-01-01

    Addition of iron sulfate to cement means transformation of water-soluble hexavalent chromium into nonwater-soluble trivalent chromium. This has been the basis for preventive measures concerning sensitization to hexavalent chromium (chromate) in cement. For some years, iron sulfate has been added to cement manufactured in the Scandinavian countries. In the present in vivo study, cements with and without iron sulfate were compared concerning their capacity to elicit allergic patch-test reactions in eight chromate-hypersensitive individuals. No patch-test reactions were obtained from a water extract of cement with iron sulfate when appropriately buffered. PMID:2137395

  12. 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.

  13. 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.

  14. Polychlorinated biphenyls (PCB), thyroid hormones and cytokines in construction workers removing old elastic sealants

    PubMed Central

    Lundholm, Cecilia; Johansson, Niklas; Wingfors, Håkan

    2008-01-01

    Objectives To estimate the internal PCB level in Swedish workers specialised in PCB abatement in buildings and to measure possible effects of PCB on thyroid function and aspects of the immune system. Methods Thirty six of 40 eligible workers (90%) removing old elastic sealants containing PCB and 33 control construction workers provided blood samples for determination of 19 PCB congeners and some other organochlorine compounds (hexachlorobenzene and p,p′-DDE), thyroid function hormones and a set of cytokines. The PCB exposed group was reinvestigated after 10 months for a trend assessment. Results The sum of 19 PCB congeners in blood plasma from the occupationally PCB-exposed group was twice the level in the controls (geometric mean 580 vs. 260 ng/g lipid; P < 0.001), and there was also some difference in p,p′-DDE between the groups while the lipid-adjusted hexachlorobenzene levels were of the same magnitude. No statistically significant increase in overall PCB levels was observed in the abatement workers at follow-up and some congeners even declined. Thyroid function was not associated with PCB exposure at the current levels and this applied also to the cytokines investigated. Conclusions Swedish workers removing old elastic sealants with PCB have a higher internal PCB load than unexposed colleague construction workers, tentatively secondary to historical exposure. A system of protective measures seemed to be efficient since no further increase was noted after a longish period of additional exposure. There was no evidence of thyroid function or immune system involvement, as expressed by a set of cytokines, at the low PCB levels recorded. PMID:18350309

  15. [Quantification of D-dimer and soluble fibrin in blood plasma of people with ischemic heart disease and hypertension].

    PubMed

    Lugovskoĭ, E V; Kolesnikova, I N; Lugovskaia, N E; Litvinova, L M; Gritsenko, P G; Gogolinskaia, G K; Liashko, E D; Kostiuchenko, E P; Remizovskiĭ, G A; Pedchenko, V N; Komisarenko, S V

    2004-01-01

    The method of D-dimer quantification in the human blood plasma has been developed using monoclonal antibodies 111-3b and II-4d. The method has been verified on the blood plasma of the patients with ischemic heart disease with and without stenocardia and with hypertension. The results showed that at ischemic heart disease with and without stenocardia and at hypertension the quantities of D-dimer in the blood plasma were generally less than the highest normal level 500 ng/ml (64.3%, 76.2% and 95%, correspondingly). The semiquantitative measurements of soluble fibrin levels in blood plasmas of the patients with ischemic heart disease and hypertension have been performed. It has been shown that the quantity of soluble fibrin at these diseases range greatly from < 0.03 mg/ml to 0.15 mg/ml. There was no correlation between the quantities of D-dimer and soluble fibrin in blood plasmas of the patients. Electrophoresis in PAAG with SDS showed that the soluble fibrin at these diseases had the mo- lecular mass of the fibrin (ogen). Thus the soluble fibrin in blood plasmas analysed consisted mainly of fibrin desAA oligomers (may be with fibrinogen incorporation) which are not stabilized by the factor XIIIa. PMID:16350758

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

    PubMed Central

    Koulaxouzidis, Georgios; Reim, Gernot; Witzel, Christian

    2015-01-01

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

  17. Optimization of acidic fibroblast growth factor (FGF-1) and its delivery through a modified degradable fibrin scaffold

    NASA Astrophysics Data System (ADS)

    Pandit, Abhay Smashikant

    The aim of this investigation was to develop a degradable fibrin wound dressing that can deliver an optimized dose of acidic fibroblast growth factor (FGF-1). This aim led to three distinct phases of study. In the first phase, a structurally modified fibrin degradable scaffold was developed and tested in a rabbit ear ulcer model. A significant increase in the angiogenic and fibroblastic response with a corresponding decrease in healing time was seen in the modified fibrin-treated ulcers as compared with untreated ulcers and ulcers treated with non-modified fibrin systems. In the second phase of the study, a biochemical factor, FGF-1, was added to this scaffold. An optimal dose of 8 mug of FGF-1 was determined to be required to initiate a desired wound-healing response in a rabbit ear ulcer model, based on an enhanced angiogenic and fibroblastic response and an increased epithelialization rate. The objective of the last phase was to investigate the efficacy of a modified scaffold as a vehicle for FGF-1. In vivo testing was conducted in a full-thickness defect model in a rabbit. Improvements were seen in the angiogenic and fibroblastic responses in the FGF-1/modified fibrin treatment group and, hence, FGF-1/modified fibrin was the preferred treatment. In conclusion, the modified fibrin/FGF-1 matrix served as a suitable vehicle for the growth factor, providing a desired healing response and a desirable release rate and, thus, was determined to be an effective scaffold.

  18. Formation and stability of interpenetrating polymer network hydrogels consisting of fibrin and hyaluronic acid for tissue engineering.

    PubMed

    Lee, Fan; Kurisawa, Motoichi

    2013-02-01

    Fibrin gel is widely used as a tissue engineering scaffold. However, it has poor mechanical properties, which often result in rapid contraction and degradation of the scaffold. An interpenetrating polymer network (IPN) hydrogel composed of fibrin and hyaluronic acid-tyramine (HA-Tyr) was developed to improve the mechanical properties. The fibrin network was formed by cleaving fibrinogen with thrombin, producing fibrin monomers that rapidly polymerize. The HA network was formed through the coupling of tyramine moieties using horseradish peroxidase (HRP) and hydrogen peroxide (H₂O₂). The degree of crosslinking of the HA-Tyr network can be tuned by varying the H₂O₂ concentration, producing IPN hydrogels with different storage moduli (G'). While fibrin gels were completely degraded in the presence of plasmin and contracted when embedded with cells, the shape of the IPN hydrogels was maintained due to structural support by the HA-Tyr networks. Cell proliferation and capillary formation occurred in IPN hydrogels and were found to decrease with increasing G' of the hydrogels. The results suggest that fibrin-HA-Tyr IPN hydrogels are a potential alternative to fibrin gels as scaffolds for tissue engineering applications that require shape stability. PMID:22943886

  19. Fundamental Investigations of the Extracellular Proteins Fibrin and Collagen in Microchannel Devices

    NASA Astrophysics Data System (ADS)

    Evans, Heather M.; Koester, Sarah; Pfohl, Thomas

    2007-03-01

    Microfluidic structures are particularly amenable to controlled investigations of protein bundle and network formation. Hydrodynamic focusing is utilized to create a diffusion-controlled gradient of reactants, enabling non-equilibrium investigations. We present studies of the blood clotting protein fibrin, a three-dimensional network formed from the enzymatic cleavage of fibrinogen monomers by the protein thrombin. Fibrin is a vital component of blood clots, and has been implicated in a variety of diseases. Real-time fluorescence microscopy and x-ray micro-diffraction are used to quantify supramolecular assembly and provide snapshots of the evolution of fibrin network formation. We also show that collagen, a ubiquitous extracellular protein, can be bundled in situ through the use of a pH gradient. An outlook toward artificial blood vessels arises from the insight that both fibrin and collagen can easily be used to coat microchannel structures. The resulting mesh forms an ideal environment for red blood cells and other cell types.

  20. A Comparison of the Mechanical and Structural Properties of Fibrin Fibers with Other Protein Fibers

    PubMed Central

    Guthold, M.; Liu, W.; Sparks, E. A.; Jawerth, L. M.; Peng, L.; Falvo, M.; Superfine, R.; Hantgan, R. R.; Lord, S. T.

    2010-01-01

    In the past few years a great deal of progress has been made in studying the mechanical and structural properties of biological protein fibers. Here, we compare and review the stiffness (Young's modulus, E) and breaking strain (also called rupture strain or extensibility, εmax) of numerous biological protein fibers in light of the recently reported mechanical properties of fibrin fibers. Emphasis is also placed on the structural features and molecular mechanisms that endow biological protein fibers with their respective mechanical properties. Generally, stiff biological protein fibers have a Young's modulus on the order of a few Gigapascal and are not very extensible (εmax < 20%). They also display a very regular arrangement of their monomeric units. Soft biological protein fibers have a Young's modulus on the order of a few Megapascal and are very extensible (εmax > 100%). These soft, extensible fibers employ a variety of molecular mechanisms, such as extending amorphous regions or unfolding protein domains, to accommodate large strains. We conclude our review by proposing a novel model of how fibrin fibers might achieve their extremely large extensibility, despite the regular arrangement of the monomeric fibrin units within a fiber. We propose that fibrin fibers accommodate large strains by two major mechanisms: (1) an α-helix to β-strand conversion of the coiled coils; (2) a partial unfolding of the globular C-terminal domain of the γ-chain. PMID:17952642

  1. Experimental and Imaging Techniques for Examining Fibrin Clot Structures in Normal and Diseased States

    PubMed Central

    Fan, Natalie K.; Keegan, Philip M.; Platt, Manu O.; Averett, Rodney D.

    2015-01-01

    Fibrin is an extracellular matrix protein that is responsible for maintaining the structural integrity of blood clots. Much research has been done on fibrin in the past years to include the investigation of synthesis, structure-function, and lysis of clots. However, there is still much unknown about the morphological and structural features of clots that ensue from patients with disease. In this research study, experimental techniques are presented that allow for the examination of morphological differences of abnormal clot structures due to diseased states such as diabetes and sickle cell anemia. Our study focuses on the preparation and evaluation of fibrin clots in order to assess morphological differences using various experimental assays and confocal microscopy. In addition, a method is also described that allows for continuous, real-time calculation of lysis rates in fibrin clots. The techniques described herein are important for researchers and clinicians seeking to elucidate comorbid thrombotic pathologies such as myocardial infarctions, ischemic heart disease, and strokes in patients with diabetes or sickle cell disease. PMID:25867016

  2. Immobilization of alkaline phosphatase on microporous nanofibrous fibrin scaffolds for bone tissue engineering.

    PubMed

    Osathanon, Thanaphum; Giachelli, Cecilia M; Somerman, Martha J

    2009-09-01

    Alkaline phosphatase (ALP) promotes bone formation by degrading inorganic pyrophosphate (PP(i)), an inhibitor of hydroxyapatite formation, and generating inorganic phosphate (P(i)), an inducer of hydroxyapatite formation. P(i) is a crucial molecule in differentiation and mineralization of osteoblasts. In this study, a method to immobilize ALP on fibrin scaffolds with tightly controllable pore size and pore interconnection was developed, and the biological properties of these scaffolds were characterized both in vitro and in vivo. Microporous, nanofibrous fibrin scaffolds (FS) were fabricated using a sphere-templating method. ALP was covalently immobilized on the fibrin scaffolds using 1-ethyl-3-(dimethylaminopropyl)carbodiimide hydrochloride (EDC). Scanning electron microscopic observation (SEM) showed that mineral was deposited on immobilized alkaline phosphatase fibrin scaffolds (immobilized ALP/FS) when incubated in medium supplemented with beta-glycerophosphate, suggesting that the immobilized ALP was active. Primary calvarial cells attached, spread and formed multiple layers on the surface of the scaffolds. Mineral deposition was also observed when calvarial cells were seeded on immobilized ALP/FS. Furthermore, cells seeded on immobilized ALP/FS exhibited higher osteoblast marker gene expression compared to control FS. Upon implantation in mouse calvarial defects, both the immobilized ALP/FS and FS alone treated group had higher bone volume in the defect compared to the empty defect control. Furthermore, bone formation in the immobilized ALP/FS treated group was statistically significant compared to FS alone group. However, the response was not robust. PMID:19501906

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

    PubMed

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

    2014-01-01

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

  4. Plasma fibronectin promotes lung metastasis by contributions to fibrin clots and tumor cell invasion.

    PubMed

    Malik, Gunjan; Knowles, Lynn M; Dhir, Rajiv; Xu, Shuping; Yang, Shuting; Ruoslahti, Erkki; Pilch, Jan

    2010-06-01

    The attachment of circulating tumor cells to the blood vessels of distant organs is an important step in metastasis. We show here that experimental lung metastasis by two cell lines, B16F1 melanoma and 3LL lung carcinoma, is greatly reduced in transgenic mice that lack plasma fibronectin. This multifunctional adhesive glycoprotein becomes cross-linked to fibrin during clotting. Here, we report that eliminating plasma fibronectin from the blood circulation reverses the prometastatic effects of blood clotting and tumor cell integrin alphavbeta3. In vitro studies showed that fibrin-fibronectin complexes, but not purified fibrin, supported tumor cell attachment and invasion. These functions correlate with the ability of fibrin-fibronectin complexes to induce the activation of integrin alphavbeta3. Our findings reveal an important contribution of plasma fibronectin in lung metastasis. Furthermore, they suggest that the previously noted effects of blood clotting on lung metastasis might be mediated in part by a fibronectin-alphavbeta3 integrin axis, in which plasma fibronectin has to be incorporated into the blood clot. PMID:20501851

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

    PubMed Central

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

    2014-01-01

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

  6. Therapeutic assessment of mesenchymal stem cells delivered within a PEGylated fibrin gel following an ischemic injury.

    PubMed

    Ricles, Laura M; Hsieh, Pei-Ling; Dana, Nicholas; Rybalko, Viktoriya; Kraynak, Chelsea; Farrar, Roger P; Suggs, Laura J

    2016-09-01

    The intent of the current study was to investigate the therapeutic contribution of MSCs to vascular regeneration and functional recovery of ischemic tissue. We used a rodent hind limb ischemia model and intramuscularly delivered MSCs within a PEGylated fibrin gel matrix. Within this model, we demonstrated that MSC therapy, when delivered in PEGylated fibrin, results in significantly higher mature blood vessel formation, which allows for greater functional recovery of skeletal muscle tissue as assessed using force production measurements. We observed initial signs of vascular repair at early time points when MSCs were delivered without PEGylated fibrin, but this did not persist or lead to recovery of the tissue in the long-term. Furthermore, animals which were treated with PEGylated fibrin alone exhibited a greater number of mature blood vessels, but they did not arterialize and did not show improvements in force production. These results demonstrate that revascularization of ischemic tissue may be a necessary but not sufficient step to complete functional repair of the injured tissue. This work has implications on stem cell therapies for ischemic diseases and also potentially on how such therapies are evaluated. PMID:27318932

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

    NASA Astrophysics Data System (ADS)

    Schmidt, Jillian Beth

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

  8. Role of clot-associated (-derived) thrombin in cell proliferation induced by fibrin clots in vitro

    PubMed Central

    Gandossi, E; Lunven, C; Berry, C N

    2000-01-01

    Thrombin is a potent mitogenic agent. Clot-associated thrombin retains its amidolytic and pro-aggregant activity. We therefore studied the ability of fibrin clots to induce proliferation in CCL39 cells (Chinese hamster lung fibroblasts), in the absence and presence of the thrombin inhibitors PPACK, recombinant hirudin (rHV2 Lys47) and heparin:antithrombin III. Fibrin clots incubated for 48 h with CCL39 cells led to significant cell proliferation, which was dependent on the concentration of thrombin used to prepare the clots. Thus, clots prepared with 91 nmol l−1 thrombin produced a similar proliferation (231±21%) to that obtained with 50 nmol l−1 thrombin in solution (213±29%). Rabbit plasma clots led to a 499±41% increase in cell number under identical conditions. Fibrin clot-induced cell proliferation was inhibited by all three thrombin inhibitors with no difference in IC50 values compared to those obtained against thrombin in solution, suggesting that cell proliferation be due to thrombin leaching from the clots. We found a time-dependent increase in thrombin release from the clots attaining a plateau at 24 h (∼61% of the total thrombin used in clot formation). Clots separated from the cells using porous cell culture chamber inserts led to similar proliferation to that of clots in contact with the cells. Thus fibrin-clot induced CCL39 proliferation is due to thrombin released from the clots. PMID:10696104

  9. Comparison of fibrin glue and suture in the healing of teat incisions in lactating goats.

    PubMed

    Alan, M; Yener, Z; Tasal, I; Bakir, B

    2008-05-01

    The aims of this study were to investigate whether fibrin glue can be used to close experimentally induced incisions of the teat (mammary papillae) in lactating goats and to compare the healing of the glued with the sutured incisions. Four clinically healthy lactating dairy goats, namely 8 mammary papillae were used. After surgical preparation of the papillae, a 3.5 cm long incision of each papilla was made through skin, muscular layer and mucosa into the papillary sinus. The wounds in the right papillae in all goats were closed with U-shaped uninterrupted 00 chromic catgut sutures. The wounds in the left papillae in all goats were closed, using fibrin glue. One incision was seen to be dehisced and fistulous one day after in fibrin glued teats. The animals were slaughtered 8 days after surgical manipulation. The mammary papillae were removed and examined in the viewpoint on gross and microscopic findings. The healing of wounds was slower and feeble in glued mammary papillary incisions, however faster and stronger in sutured incisions on day 8 after operations. But, available outcomes like less tissue thickness and positive cosmetic results could be obtained byfibrin glue used on mammary papillary incisions, which are very important for teats to be milked by hand and milking machine. Results suggest that it is advisable to use only one or two simple interrupted sutures in teat incisions glued with fibrin to prevent the dehiscence but with a more reliable healing than the sutured incisions. PMID:18547021

  10. Human umbilical cord stem cell encapsulation in novel macroporous and injectable fibrin for muscle tissue engineering.

    PubMed

    Liu, Jun; Xu, Hockin H K; Zhou, Hongzhi; Weir, Michael D; Chen, Qianming; Trotman, Carroll Ann

    2013-01-01

    There has been little research on the seeding of human umbilical cord mesenchymal stem cells (hUCMSCs) in three-dimensional scaffolds for muscle tissue engineering. The objectives of this study were: (i) to seed hUCMSCs in a fibrin hydrogel containing fast-degradable microbeads (dMBs) to create macropores to enhance cell viability; and (ii) to investigate the encapsulated cell proliferation and myogenic differentiation for muscle tissue engineering. Mass fractions of 0-80% of dMBs were tested, and 35% of dMBs in fibrin was shown to avoid fibrin shrinkage while creating macropores and promoting cell viability. This construct was referred to as "dMB35". Fibrin without dMBs was termed "dMB0". Microbead degradation created macropores in fibrin and improved cell viability. The percentage of live cells in dMB35 reached 91% at 16 days, higher than the 81% in dMB0 (p<0.05). Live cell density in dMB35 was 1.6-fold that of dMB0 (p<0.05). The encapsulated hUCMSCs proliferated, increasing the cell density by 2.6 times in dMB35 from 1 to 16 days. MTT activity for dMB35 was substantially higher than that for dMB0 at 16 days (p<0.05). hUCMSCs in dMB35 had high gene expressions of myotube markers of myosin heavy chain 1 (MYH1) and alpha-actinin 3 (ACTN3). Elongated, multinucleated cells were formed with positive staining of myogenic specific proteins including myogenin, MYH, ACTN and actin alpha 1. Moreover, a significant increase in cell fusion was detected with myogenic induction. In conclusion, hUCMSCs were encapsulated in fibrin with degradable microbeads for the first time, achieving greatly enhanced cell viability and successful myogenic differentiation with formation of multinucleated myotubes. The injectable and macroporous fibrin-dMB-hUCMSC construct may be promising for muscle tissue engineering applications. PMID:22902812

  11. Fibrin deposition following bile duct injury limits fibrosis through an αMβ2-dependent mechanism.

    PubMed

    Joshi, Nikita; Kopec, Anna K; Ray, Jessica L; Cline-Fedewa, Holly; Nawabi, Atta; Schmitt, Timothy; Nault, Rance; Zacharewski, Timothy R; Rockwell, Cheryl E; Flick, Matthew J; Luyendyk, James P

    2016-06-01

    Coagulation cascade activation and fibrin deposits have been implicated or observed in diverse forms of liver damage. Given that fibrin amplifies pathological inflammation in several diseases through the integrin receptor αMβ2, we tested the hypothesis that disruption of the fibrin(ogen)-αMβ2 interaction in Fibγ(390-396A) mice would reduce hepatic inflammation and fibrosis in an experimental setting of chemical liver injury. Contrary to our hypothesis, α-naphthylisothiocyanate (ANIT)-induced liver fibrosis increased in Fibγ(390-396A) mice, whereas inflammatory cytokine expression and hepatic necrosis were similar to ANIT-challenged wild-type (WT) mice. Increased fibrosis in Fibγ(390-396A) mice appeared to be independent of coagulation factor 13 (FXIII) transglutaminase, as ANIT challenge in FXIII-deficient mice resulted in a distinct pathological phenotype characterized by increased hepatic necrosis. Rather, bile duct proliferation underpinned the increased fibrosis in ANIT-exposed Fibγ(390-396A) mice. The mechanism of fibrin-mediated fibrosis was linked to interferon (IFN)γ induction of inducible nitric oxide synthase (iNOS), a gene linked to bile duct hyperplasia and liver fibrosis. Expression of iNOS messenger RNA was significantly increased in livers of ANIT-exposed Fibγ(390-396A) mice. Fibrin(ogen)-αMβ2 interaction inhibited iNOS induction in macrophages stimulated with IFNγ in vitro and ANIT-challenged IFNγ-deficient mice had reduced iNOS induction, bile duct hyperplasia, and liver fibrosis. Further, ANIT-induced iNOS expression, liver fibrosis, and bile duct hyperplasia were significantly reduced in WT mice administered leukadherin-1, a small molecule that allosterically enhances αMβ2-dependent cell adhesion to fibrin. These studies characterize a novel mechanism whereby the fibrin(ogen)-integrin-αMβ2 interaction reduces biliary fibrosis and suggests a novel putative therapeutic target for this difficult-to-treat fibrotic disease. PMID

  12. 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…

  13. 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.

  14. Perturbation analysis for patch occupancy dynamics

    USGS Publications Warehouse

    Martin, Julien; Nichols, James D.; McIntyre, Carol L.; Ferraz, Goncalo; Hines, James E.

    2009-01-01

    Perturbation analysis is a powerful tool to study population and community dynamics. This article describes expressions for sensitivity metrics reflecting changes in equilibrium occupancy resulting from small changes in the vital rates of patch occupancy dynamics (i.e., probabilities of local patch colonization and extinction). We illustrate our approach with a case study of occupancy dynamics of Golden Eagle (Aquila chrysaetos) nesting territories. Examination of the hypothesis of system equilibrium suggests that the system satisfies equilibrium conditions. Estimates of vital rates obtained using patch occupancy models are used to estimate equilibrium patch occupancy of eagles. We then compute estimates of sensitivity metrics and discuss their implications for eagle population ecology and management. Finally, we discuss the intuition underlying our sensitivity metrics and then provide examples of ecological questions that can be addressed using perturbation analyses. For instance, the sensitivity metrics lead to predictions about the relative importance of local colonization and local extinction probabilities in influencing equilibrium occupancy for rare and common species.

  15. 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.

  16. Label-free, sensitivity detection of fibrillar fibrin using gold nanoparticle-based chemiluminescence system.

    PubMed

    Zhang, Yuanfu; Liu, Jifeng; Liu, Ting; Li, Haibo; Xue, Qingwang; Li, Rui; Wang, Lei; Yue, Qiaoli; Wang, Shuhao

    2016-03-15

    A novel, label-free, gold nanoparticles (AuNPs)-based chemiluminescence assay has been developed for the detection of fibrillar fibrin. The method relied on the interaction of fibrinogen (Fib) with AuNPs and the aggregated AuNPs induce a strong luminol-H2O2 chemiluminesecence (CL) signal. We prepared the 12-nm-diameter AuNPs which well dispersed in the solution. Fib was absorbed on the surface of AuNPs against the aggregation of AuNPs in 1.0M NaCl. Otherwise, Fib was catalyzed to form fibrillar fibrin in the presence of thrombin. The fibrin induced AuNPs aggregated in the presence of NaCl solution. The catalytic activity of aggregated AuNPs on the luminol-H2O2 CL reaction is greatly enhanced. This allows us to utilize the luminol-H2O2 CL system for quantitative analysis of thrombin, which was used to denote fibrosis degree of Fib. The assay showed a linear toward fibrillar fibrin concentration in the range of 2.7 × 10(-15)-2.7 × 10(-13)M with a correlation of 0.9920. The limit of detection for fibrin was experimentally determined to be 1 fM, based on a signal-to-noise ratio (S/N) of 3. Relative to conventional methods, this method offers the advantages of higher sensitivity and selectivity and lower cost, showing great potential for medical diagnosis. PMID:26397422

  17. The role of leukocytes in the pathogenesis of fibrin deposition in bovine acute lung injury.

    PubMed Central

    Car, B. D.; Suyemoto, M. M.; Neilsen, N. R.; Slauson, D. O.

    1991-01-01

    The peculiarly fibrinous nature of bovine acute lung injury due to infection with Pasteurella haemolytica A1 suggests an imbalance between leukocyte-directed procoagulant and profibrinolytic influences in the inflamed bovine lung. Calves with experimental pneumonia produced by intratracheal inoculation with P. haemolytica A1 developed acute locally extensive cranioventral fibrinopurulent bronchopneumonia. Pulmonary alveolar macrophages (PAM) recovered by segmental lavage from affected lung lobes were 30 times more procoagulant than PAM obtained from unaffected lung lobes and 37-fold more procoagulant than PAM from control calf lungs. Unlike the enhancement of procoagulant activity, profibrinolytic activity (plasminogen activator amidolysis) of total lung leukocytes (PAM and plasminogen activator neutrophils [PMN]) was decreased 23 times in cells obtained from affected lung lobes and also was decreased four times in cells obtained from unaffected lobes of infected animals. This marked imbalance in cellular procoagulant and fibrinolytic activity probably contributes significantly to enhanced fibrin deposition and retarded fibrin removal. In addition, PAM from inflamed lungs were strongly positive for bovine tissue factor antigen as demonstrated by immunocytochemistry. Intensely tissue factor-positive PAM enmeshed in fibrinocellular exudates and positive alveolar walls were situated such that they were likely to have, in concert, initiated extrinsic activation of coagulation in the acutely inflamed lung. These data collectively suggest that enhanced PAM-directed procoagulant activity and diminished PAM- and PMN-directed profibrinolytic activity represent important modifications of local leukocyte function in bovine acute lung injury that are central to the pathogenesis of lesion development with extensive fibrin deposition and retarded fibrin removal. Images Figure 2 Figure 3 PMID:2024707

  18. Imaging Thromboembolism with Fibrin-Avid 99mTc-Peptide: Evaluation in Swine

    PubMed Central

    Aruva, Mohan R.; Daviau, Judy; Sharma, Shubh S.; Thakur, Mathew L.

    2006-01-01

    A pentapeptide, Gly-Pro-Arg-Pro-Pro, with high affinity for α-chain-fibrin was labeled with 99mTc (99mTc-TP850) and evaluated in swine to image experimental venous thromboembolism (deep vein thrombosis [DVT]) and pulmonary embolism (PE). Methods Scatchard analysis was performed to determine fibrin affinity for TP850 and the number of binding sites (receptors) per milligram of fibrin. DVT was induced in the left jugular vein and PE was induced by introducing a preformed autologous blood clot into the right atrium using a 7-French introducer sheath inserted into the right jugular vein. 99mTc-TP850 was injected at 4, 24, 48, 72, 96, or 120 h later. Animals were imaged for up to 4 h after injection, heparinized, and sacrificed. Lungs were extirpated, radiographed, and imaged, and the PE was removed. Other tissues, including blood and normal lungs, were harvested and, concomitantly, 99mTc was counted for determination of target-to-tissue ratios and the percentage injected dose per gram of tissue. Results The affinity for human fibrin was 10−9 mol/L and there were >1015 receptors per milligram of fibrin. DVT and PE were visualized for up to 4 h after injection with high DVT/blood (7.9–22.6), DVT/muscle (31.1–89.4), PE/blood (1–155), and PE/lung (0.8–245) ratios. Thereafter, the PEs fragmented spontaneously below the spatial resolution of the γ-camera and, despite the high associated radioactivity, could not be localized in vivo. The fragmented clots were detectable by scintigraphy on excised lungs and provided excellent concordance with radiograms. Conclusion 99mTc-TP850 with its modest affinity (10−9 mol/L), rapid blood clearance, and high DVT and PE uptake is a promising agent for imaging vascular thrombosis. PMID:16391200

  19. Immunohistochemical evaluation of tissue factor, fibrin/fibrinogen and D-dimers in canine gliomas.

    PubMed

    de la Fuente, Cristian; Pumarola, Martí; Blasco, Ester; Fernández, Francisco; Viu, Judit; Añor, Sònia

    2014-06-01

    In human gliomas, tissue factor (TF) is overexpressed, associated with the grade of malignancy and influences tumour biology. Intra-tumoural fibrin/fibrinogen deposition and activation of the fibrinolytic system also play a role in tumour cell proliferation and angiogenesis. The first aim of the present study was to investigate TF expression and the presence of fibrin/fibrinogen and D-dimers in canine glioma biopsies, graded according to the World Health Organization (WHO) classification of tumours of the central nervous system. The second aim was to investigate the occurrence of intravascular thrombosis (IVT) in canine gliomas, as a potential histological marker of glioma type or grade of malignancy. An immunohistochemical study using antibodies against TF, fibrin/fibrinogen and D-dimers was performed with 24 glioma samples, including 15 oligodendrogliomas, 6 astrocytomas and 3 mixed gliomas. Immunohistochemical data were statistically analysed to determine whether there was any relationship between glioma type and grade of malignancy. All gliomas were moderate to strongly positive for TF and the staining score was significantly higher (P = 0.04) in high-grade (III or IV) than in low-grade (II) gliomas. Intra-tumoural fibrin/fibrinogen deposition was detected in all tumour biopsies assessed, and D-dimers were detected in 17/24 gliomas. IVT was a frequent finding, but was not linked to a specific glioma type or malignancy grade. TF expression, fibrin/fibrinogen deposition, extravascular fibrinolytic system activation and IVT occur in canine gliomas. Canine glioma might be a suitable model for studying coagulation and fibrinolysis as potential therapeutic targets for human gliomas. PMID:24745770

  20. Inhibition of fibrin polymerization by fragment d is affected by calcium, Gly-Pro-Arg and Gly-His-Arg.

    PubMed

    Furlan, M; Rupp, C; Beck, E A

    1983-01-12

    Fibrinopeptides A and B were removed from purified human fibrinogen by bovine thrombin, whereas the snake venom protease batroxobin only split fibrinopeptide A from fibrinogen. Aggregation of the resulting desAB- and desA-fibrin monomers was evaluated by recording the turbidity of incubation mixtures. Fibrin assembly was strongly accelerated by increasing the calcium concentration from 10(-5) to 10(-3) M. Fragment D was obtained from fibrinogen by proteolytic degradation with plasmin in the presence of Ca2+. At a 4-fold molar concentration relative to fibrinogen, fragment D dramatically inhibited fibrin polymerization at up to 10(-4) M Ca2+. This anticlotting activity was, however, much less pronounced at 10(-3) M Ca2+. The thrombin clotting time, measured on human plasma, was prolonged by fragment D in a dose-dependent manner. In citrate-containing plasma, the fibrinogen clotting was significantly delayed by an equimolar concentration of fragment D. In barium sulfate-adsorbed oxalated plasma, containing 2.5 mM Ca2+, the same amount of fragment D hardly affected fibrin polymerization. We conclude that fragment D has no important anticlotting effect under physiological conditions. The synthetic peptide Gly-Pro-Arg, corresponding to the amino-terminal sequence of the fibrin alpha-chain, inhibited aggregation of both desA-fibrin and desAB-fibrin at 10(-3) M Ca2+. The inhibition of desAB-fibrin polymerization by Gly-Pro-Arg was abolished at 10(-5) M Ca2+. In addition, Gly-Pro-Arg depressed the anticlotting activity of fragment D at low calcium concentration. An analogue of the amino-terminus of fibrin beta-chain, Gly-His-Arg, strongly accelerated aggregation of desA-fibrin monomers, but only moderately enhanced polymerization of desAB-fibrin monomers at 10(-5) M Ca2+, both in the presence and in the absence of fragment D. This activating effect of Gly-His-Arg was abolished at 10(-3) M Ca2+. It is suggested that the binding of calcium, Gly-His-Arg, and possibly also Gly