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Comparative study of tissue response to polyglecaprone 25, polyglactin 910 and polytetrafluorethylene suture materials in rats
Nary Filho, Hugo;Matsumoto, Mariza Akemi;Batista, Aline Carvalho;Lopes, Luís César;Sampaio Góes, Fernanda Costa Grizzo de;Consolaro, Alberto;
Brazilian Dental Journal , 2002, DOI: 10.1590/S0103-64402002000200002
Abstract: the authors evaluated the biocompatibility of three suture materials, polyglecaprone 25, polyglactin 910 and polytetrafluorethylene, implanted into subcutaneous tissue in the dorsal region of 20 wistar albinus rats. after periods of 2, 7, 14 and 21 days, the rats were sacrificed and the specimens were processed for routine histotechnical analysis and stained with hematoxylin and eosin. the rate of fibrosis, angioblastic and fibroblastic proliferation, and also the intensity of inflammation were observed with the optic microscope. the results showed that polyglecaprone 25 suture material induced a mild inflammatory reaction, followed by polyglactin 910 and polytetrafluorethylene, respectively. such biological behavior must be considered during the selection of the suture material to be used in oral surgery.
Comparative study of tissue response to polyglecaprone 25, polyglactin 910 and polytetrafluorethylene suture materials in rats  [cached]
Nary Filho Hugo,Matsumoto Mariza Akemi,Batista Aline Carvalho,Lopes Luís César
Brazilian Dental Journal , 2002,
Abstract: The authors evaluated the biocompatibility of three suture materials, polyglecaprone 25, polyglactin 910 and polytetrafluorethylene, implanted into subcutaneous tissue in the dorsal region of 20 Wistar albinus rats. After periods of 2, 7, 14 and 21 days, the rats were sacrificed and the specimens were processed for routine histotechnical analysis and stained with hematoxylin and eosin. The rate of fibrosis, angioblastic and fibroblastic proliferation, and also the intensity of inflammation were observed with the optic microscope. The results showed that polyglecaprone 25 suture material induced a mild inflammatory reaction, followed by polyglactin 910 and polytetrafluorethylene, respectively. Such biological behavior must be considered during the selection of the suture material to be used in oral surgery.
Expanded polytetrafluoroethylene and polypropylene in the repairing of abdominal wall defects in Wistar rats: comparative study
d'Acampora, Armando José;Joli, Fabrícia Slomski;Tramonte, Ricardo;
Acta Cirurgica Brasileira , 2006, DOI: 10.1590/S0102-86502006000600010
Abstract: purpose: to compare the use of polypropylene and ptfe meshes in the treatment of incisional hernias made experimentally on wistar rats. methods: the experiment used 24 wistar rats divided into three cohorts: c-a (ressection of a segment of abdominal wall), e-a (ressection and placement of ptfee mesh), e-b (resection and placement of polypropylene mesh). after 28 days, the mesh and the surrounding tissue were removed and submitted to macroscopic analysis (assessment of the abdominal wall for presence of abscess in the surgical wound and/or skin necrosis, and adhesions) as well as microscopic analysis (presence of fibrosis, necrosis and abscess, counting of macrophages, mononuclears and polymorphonuclears). results: adhesions and abscesses in the surgical wound were observed more commonly associated to the group treated with ptfee. the size of the fibrous tissue was greater in the group treated with polypropylene. cohort e-a showed ptfee mesh enveloped by organized fine connective tissue. no groups presented necrosis on the site of the insertion. the highest mononuclear inflammatory reaction occurred in association to ptfee when compared to the control group, but the findings for the polypropylene mesh were also significant when compared to the control group. in the analysis of the results obtained for cohorts e-a and e-b, a minimal occurrence of polymorphonuclears was noticed in both groups, which indicates low tissue reactivity to both materials used in the present experiment. conclusion: even with epithelization and proliferation of connective tissue, anchorage between ptfee and abdominal wall is insufficient, which can result in reherniations.
The effect of Gel Foam on post laminectomy epidural fibrosis in rabbits
Lotfinia I,Kallagee E,Mesgaree M,Esmaelee H
Tehran University Medical Journal , 2009,
Abstract: "nBackground: Epidural fibrosis (EF) is a part of normal physiological tissue response to laminectomy and it may be an important cause of failed back surgery syndrome (FBSS). The objective of this study was to evaluate the effect of using gel foam after laminectomy on reduction of epidural fibrosis. "nMethods: In this prospective study forty five rabbits were recruited. The cases undergone bilateral laminectomy at the L4 and L5 lumbar levels under an approved surgical protocol. After eight weeks the rabbits were sacrificed and the spinal segments from L3 to L6 were removed en bloc. The amount of scar tissue at the laminectomy defect was scored. The fibroblast and inflammatory cell counts were also compared between two groups. "nResults: In this study 55% of group A rabbits were placed in grade 0 or I, grade II fibrosis could be detected in the remaining 45%. In group B these amounts were 73.7% and 26.3% respectively, which no significant statistical difference could be detected between two arms (p=0.189). Comparing the quantity of fibroblasts 40% of group A rabbits were recognized as grade I and the other 60% as grade II and grade I fibrosis was discovered in 42.1% of group B rabbits, while other 57.9% suffered from grade II fibrosis, again no significant statistical difference could be attributed between two arms (p=0.576). Also comparing inflammatory cell counts detected in the specimens no significant statistical difference could be detected either (p=0.465). "nConclusion: According to this study using gel foam during the laminectomy surgery in rabbits has no obvious effect in reducing post laminectomy epidural fibrosis after eight weeks of follow-up.
Comparative evaluation of the effect of silicone and teflon in prevention of epidural fibrosis after laminectomy in rat
Sheikh Rezaei A,Fakhr Tabatabaei SA,Khoshnevisan A,Marzban H
Tehran University Medical Journal , 2001,
Abstract: There are many studies about epidural fibrosis after surgical manipulation of the spine. We have studied formation of the post laminectomy epidural fibrosis after application of two materials (Silicone and Teflon) in this report. This expriment is on two groups of rats. Two separated laminectomies were done in each rat, one serving as control while in the other laminectomy spaces Silicone was used in group A and Teflon in group B. Laminectomy spaces were evaluated with gross dissection and histologic studies after 6 weeks. Silicone decreased intermuscular scar, deep scar, dural adhesion and collagen fiber density in epidural space. Teflon decreased dural adhesion and collagen fiber density but did not decrease intermuscular and deep scar formation in epidural space.
Effect of Honey on Peridural Fibrosis Formation after Laminectomy in Rats: A Novel Experimental Study
Majid Reza Farrokhi,Mohammad Vasei,Saeed Fareghbal,Atefeh Bakhtazad
Evidence-Based Complementary and Alternative Medicine , 2011, DOI: 10.1155/2011/504967
Abstract: Despite progress in surgical techniques, some patients still face postoperative recurrence of pain. Recently, more attention has been focused on peridural fibrosis (PF), which may be responsible for recurrent pain after laminectomy or discectomy. Honey has been shown to exert anti-inflammatory effects on exposed tissues besides its well-known antibacterial properties. The aim of this study were to investigate the effects of honey on the prevention of postlaminectomy fibrosis formation in a rat model. A controlled blinded study was performed in 45 male adult white Sprague-Dawley rats that underwent laminectomy at the L5-L6 levels. They were divided into 3 groups (A, B, and C) of 15 rats each. Group A (sham) underwent laminectomy and group B was treated with normal saline at the laminectomy site. Rats in group C received 0.1 mL honey at the laminectomy site. All rats were killed 4 weeks after laminectomy. PF was found in 5 rats (33%) of control groups A and B, and in 2 rats (10%) in honey-treated laminectomy group C. The difference was not statistically significant. Wound healing was not affected, and there was no cerebrospinal fluid leakage. Although honey appears to be safe, it cannot cause a significant reduction of PF formation after lumbar laminectomy in rats.
Polytetrafluorethylene added to acrylic resins: mechanical properties
Straioto, Fabiana Gouveia;Ricomini Filho, Antonio Pedro;Fernandes Neto, Alfredo Júlio;Del Bel Cury, Altair Antoninha;
Brazilian Dental Journal , 2010, DOI: 10.1590/S0103-64402010000100009
Abstract: the addition of different polymers, such as polytetrafluorethylene (ptfe), to denture base resins could be an option to modify acrylic resin mechanical properties. this study evaluated the surface hardness, impact and flexural strength, flexural modulus and peak load of 2 acrylic resins, one subjected to a long and another subjected to a short polymerization cycle, which were prepared with or without the addition of 2% ptfe. four groups were formed according to the polymerization cycle and addition or not of ptfe. forty specimens were prepared for each test (10 per group) with the following dimensions: hardness (30 mm diameter x 5 mm thick), impact strength (50 x 6 x 4 mm) and flexural strength (64 x 10 x 3.3 mm) test. the results of the flexural strength test allowed calculating flexural modulus and peak of load values. all tests were performed in accordance with the iso 1567:1999 standard. data were analyzed statistically by anova and tukey's test with the level of significance set at 5%. no statistically significant differences (p>0.05) were found for surface hardness. flexural strength, impact strength and peak load were significantly higher (p<0.05) for resins without added ptfe. the flexural modulus of the acrylic resin with incorporated 2% ptfe polymerized by long cycle was significantly higher (p<0.05) than that of the other resins. within the limits of this study, it may be concluded that the addition of ptfe did not improve the mechanical properties of the evaluated acrylic resins.
Effect of Laminectomy on Stability of Lumbar Spine Effect of Laminectomy on Stability of Lumbar Spine  [cached]
Petr Tichy,Zdenek Horak,Jana Sindelarova
Bulletin of Applied Mechanics , 2009,
Abstract: The paper aims at the presentation of the lumbar spine finite element model used in a study of segmental kinematics including the tissue loading. Lumbar spine FE-model consisting of the three lumbar vertebras, two disc (including annulus and nucleus) and vast variety of ligaments. The primary model objective is its verification by experimental test data obtained from cadaver spine segments. A confirmed model was used for a study of various range of laminectomy effect. On this model we simulate a various loading states witch can spine segment arrive at under physiologic conditions (compression, flexion, extension and lateral bending). FE-model could predict the laminectomy impact on the operation approach. The paper aims at the presentation of the lumbar spine finite element model used in a study of segmental kinematics including the tissue loading. Lumbar spine FE-model consisting of the three lumbar vertebras, two disc (including annulus and nucleus) and vast variety of ligaments. The primary model objective is its verification by experimental test data obtained from cadaver spine segments. A confirmed model was used for a study of various range of laminectomy effect. On this model we simulate a various loading states witch can spine segment arrive at under physiologic conditions (compression, flexion, extension and lateral bending). FE-model could predict the laminectomy impact on the operation approach.
Nanotribological characterization of industrial Polytetrafluorethylene-based coatings by atomic force microscopy  [PDF]
A. Podesta',G. Fantoni,P. Milani,C. Guida,S. Volponi
Physics , 2002, DOI: 10.1016/S0040-6090(02)00778-2
Abstract: We present the result of a systematic study of the tribological properties of industrial Polytetrafluorethylene (PTFE)-based coatings carried out with an atomic force microscope. A new characterization protocol allowed the reliable and quantitative assessment of the friction coefficient and adhesion forces at the sub-micrometer scale even for highly corrugated industrial samples. We have studied and compared PTFE coatings charged with different additives in dry and humid environment. The influence of additives and humidity on the friction coefficient and on adhesion forces has been investigated using standard silicon nitride tips as sliders in the low-load regime.
Polytetrafluorethylene-Au as a substrate for surface-enhanced Raman spectroscopy  [cached]
?vátora Pavel,?ezanka Pavel,Prokopec Vadym,Siegel Jakub
Nanoscale Research Letters , 2011,
Abstract: This study deals with preparation of substrates suitable for surface-enhanced Raman spectroscopy (SERS) applications by sputtering deposition of gold layer on the polytetrafluorethylene (PTFE) foil. Time of sputtering was investigated with respect to the surface properties. The ability of PTFE-Au substrates to enhance Raman signals was investigated by immobilization of biphenyl-4,4'-dithiol (BFD) from the solutions with various concentrations. BFD was also used for preparation of sandwich structures with Au or Ag nanoparticles by two different procedures. Results showed that PTFE can be used for fabrication of SERS active substrate with easy handle properties at low cost. This substrate was sufficient for the measurement of SERS spectrum of BFD even at 10-8 mol/l concentration.
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