Histological changes in the rat common carotid artery following simultaneous topical application of cotton sheet and cyanoacrylate glue.
(9/341)
Histological changes in and around the arterial walls of rats were investigated following simultaneous topical application of cotton sheet and cyanoacrylate glue. The bilateral common carotid arteries were exposed using sterile techniques, and the test materials were applied to the right artery. The left artery served as a control. Changes in arterial histology were evaluated at 2 weeks, 1 month, 2 months, and 3 months after surgery. Extensive inflammation consisting primarily of histiocytes and multinuclear giant cells was observed around the materials, but tended to decrease by 3 months. Necrosis in the media and fibrosis in the adventitia initially appeared around 2 weeks, and became advanced by 2-3 months. At 2-3 months, disruption of elastic fibers and marked fibrosis in the media were seen, and endothelial proliferation in the intima appeared. Intimal proliferation was observed at both the experimental and other sites of the vessels. The present results suggest that simultaneous use of the test materials can cause the arterial occlusive lesions observed following aneurysmal surgery. (+info)
The S130K fibroblast growth factor-1 mutant induces heparin-independent proliferation and is resistant to thrombin degradation in fibrin glue.
(10/341)
OBJECTIVE: Site-directed mutagenesis is an important technique that can alter cytokine function, thereby eliciting desired responses. S130K is a mutation of fibroblast growth factor-1 (FGF-1), with lysine replacing serine in the heparin-binding site. We measured molecular stability and mitogenic activity of FGF-1 and S130K, both in the media and when suspended in fibrin glue (FG), on smooth muscle cells (SMCs) and endothelial cells (ECs) to determine if the mutation altered the function and potential clinical applicability. METHODS: EC and SMC proliferation of soluble FGF-1 or S130K at 0, 0. 1, 1, 10, or 100 ng/mL with heparin at 0, 5, 50, or 500 units (U)/mL was measured on growth-arrested cells in serum-free media. EC and SMC proliferation assays with cells on FG containing either FGF-1 or S130K at 0, 1, 10, 100, or 1000 ng/mL in combination with heparin at 0, 5, 50 or 500 U/mL were also performed during the exponential growth phase. Molecular degradation by thrombin was measured by sodium dodecylsulfate-polyacrylamide gel electrophoresis. RESULTS: S130K induces greater EC and SMC proliferation in the absence of heparin than FGF-1 does (P <.0001 for both the 10 and 100 ng/mL doses). S130K is also significantly more potent than FGF-1 in the presence of heparin. Heparin in the media enhances cytokine-induced SMC and EC proliferation at doses of 5 U/mL, but inhibits SMC proliferation at concentrations of 500 U/mL. For the FG data, unlike FGF-1, S130K induces EC and SMC proliferation in the absence of heparin. The addition of 5 U/mL of heparin enhances the proliferation induced by S130K. For ECs, as the heparin dose increases to 50 U/mL, proliferation decreases, as compared with the 5 U/mL concentration when either FGF-1 or S130K in the FG was compared at concentrations of 10, 100, and 1000 ng/mL (P <.01). S130K is more potent in FG than is FGF-1 both with and without heparin and exhibits maximal EC and SMC proliferation at 10 ng/mL, whereas FGF-1 activity is maximal at 100 ng/mL. Gel electrophoresis demonstrated that S130K was relatively more resistant to thrombin degradation than FGF-1. CONCLUSIONS: Site-directed mutagenesis changed the potency and the heparin dependency on cellular proliferation of FGF-1 in vitro. These techniques should allow the delivery of mutant growth factors to areas of vascular intervention to induce specific, desired responses. We believe that these studies will enhance our knowledge of the function of various regions of the FGF-1 molecule, allowing us to more precisely design increasingly more useful FGF-1 mutants. (+info)
Atomic force microscopy of gastric mucin and chitosan mucoadhesive systems.
(11/341)
Atomic force microscopy has been utilized to probe, at a molecular level, the interaction between purified pig gastric mucin (PGM) and a mucoadhesive cationic polymer, chitosan (sea cure 210+), with a low degree (approx. 11%) of acetylation. Images were produced detailing the structures of both PGM and chitosan in 0.1 M acetate buffer (pH 4.5), followed by the complex of the two structures in the same buffer. PGM in 0.1 M acetate buffer revealed long linear filamentous structures, consistent with earlier electron microscopy and scanning tunnelling micoscopy studies. The chitosan molecules also adopted a linear conformation in the same buffer, although with a smaller average length and diameter. They appeared to adopt a stiff-coil conformation consistent with earlier hydrodynamic measurements. The complexes formed after mixing PGM and chitosan together revealed large aggregates. In 0.1 M ionic strength buffer they were of the order of 0.7 microm in diameter, consistent with previous electron microscopy studies. The effect of ionic strength of the buffer on the structure of the complex was also studied and, together with molecular hydrodynamic data, demonstrates that the interaction is principally electrostatic in nature. (+info)
Biological tissue adhesive for multiple use in the accident and emergency department.
(12/341)
OBJECTIVE: To assess the strength of the glue and microbial contamination over 28 days from opening a vial of tissue adhesive in the accident and emergency setting, and to quantify cost savings of repeated use of the vials. METHOD: (1) Strips of reinforced nylon and a specially constructed piece of apparatus designed to measure the force at which the glue gave way were used to measure the strength of the tissue adhesive at various times after the glue was opened to assess if the glue strength deteriorated over time. (2) Microbial contamination of the glue was assessed. RESULTS: There was no deterioration in the glue strength over time. There was no evidence of microbial contamination of the glue. CONCLUSION: Cyanoacrylate tissue adhesive can safely be reused for a period of 28 days after opening with no risk of degradation of glue strength or contamination with micro-organisms. In our department this represents a potential saving of l5400 per year. (+info)
Use of a platelet-fibrinogen-thrombin mixture as a corneal adhesive: experiments with sutureless lamellar keratoplasty in the rabbit.
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A platelet-fibrinogen-thrombin mixture utilizing autologous platelets was studied for its potential as a corneal adhesive. In the rabbit it demonstrated sufficient adhesive properties to allow 50 per cent of lamellar keratoplasties (autotransplants) to remain in place without the use of sutures. The mixture retains significant adhesive properties for four to six days. It is simple to prepare and apply. It also appears nonantigenic and nontoxic to the cornea; it does not incite inflammation, nor interfere with corneal clarity or the regrowth of corneal epithelium. (+info)
Endoluminal reconstruction of the arterial wall with endothelial cell/glue matrix reduces restenosis in an atherosclerotic rabbit.
(14/341)
OBJECTIVES: The objectives of this study were 1) to improve the attachment of reimplanted endothelial cells (EC) using a fibrin glue, and 2) to assess the impact of endothelial reseeding on restenosis eight weeks after balloon angioplasty. BACKGROUND: A possible mechanism contributing to restenosis after balloon angioplasty is the loss of the EC lining. Previous attempts to reseed EC had little effect due to rapid loss of the seeded cells. METHODS: Twelve atherosclerotic rabbits were subjected to angioplasty of iliac arteries and reseeding procedure. One iliac artery was subjected to EC/glue reconstruction and a contralateral site to EC seeding without glue. The animals were sacrificed after 4 h. In another series 12 rabbits were treated in the same fashion and were restudied at eight weeks. Additionally, in 10 animals one iliac was subjected to glue treatment, and another served as control. RESULTS: Histological examination demonstrated the ability of this method to reattach the EC/glue matrix circumferentially to 68.0 +/- 6.7% of the arterial wall in comparison with 13.5 +/- 3.9% reattachment after EC seeding. Morphometry at eight weeks showed that the lumen area was significantly greater in the EC/glue group (1.23 +/- 0.35 mm2) than in the EC seeding alone (0.65 +/- 0.02 mm2) and 0.72 +/- 0.41 mm2 in the glue group. This was principally accounted for by the statistically significant differences in the intimal area (0.76 +/- 0.18 mm vs. 1.25 +/-0.26 mm2 and 1.01 +/- 0.53 mm2, respectively). CONCLUSIONS: The attachment of EC after angioplasty can be greatly improved with fibrin glue matrix. The near 70% endothelial coverage achieved by this method resulted in a significant reduction of restenosis in atherosclerotic rabbit. (+info)
Beneficial effect of BioGlue surgical adhesive in repair of iatrogenic aortic dissection.
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We report the benefits of using BioGlue surgical adhesive to repair an iatrogenic aortic rupture and dissection that resulted from cannulation of the ascending aorta during open-heart surgery. (+info)
Prevention of the adverse effects of aprotinin in autologous fibrin glue.
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To avoid the adverse effects of aprotinin (Apr) in autologous fibrin glue, we compared the inhibitory properties of four commercial anti-fibrinolytic agents (tranexamic acid (Tra), epsilon-aminocaproic acid (Ips), gabexate mesilate (Gab) and nafamostat mesilate (Naf)). The optimum conditions for the lysing of fibrin glue were an incubation temperature of 37 degrees C, and incubation medium containing urokinase at 100 U/ml and plasminogen at 100 mU/ml (for the washed glue), or neither (for unwashed glue). Fibrin glues without an anti-fibrinolytic agent were quickly lysed in the incubation medium, while those with an anti-fibrinolytic agent were slowly lysed dose-dependently. Naf was the most potent inhibitor and had high affinity for the glue, but the other agents were poor inhibitors and had low affinity. The inhibition potency (IP) of each agent did not correlate with hydrophobicity, but a good correlation was obtained between the remaining coefficient (RC) and hydrophobicity. Naf did not affect the adhesive strength of the glue. These results indicate that Naf is the most suitable anti-fibrinolytic agent to replace Apr. (+info)