(33/341) Fibrinogen inhibits fibroblast-mediated contraction of collagen.
Extracellular matrix changes in composition and organization as it transitions from the provisional matrix of the fibrin/platelet plug to collagen scar in healed wounds. The manner in which individual matrix proteins affect these activities is not well established. In this article we describe the interactions of two important extracellular matrix components, fibrin and collagen, using an in vitro model of wound contraction, the fibroblast-populated collagen lattice. We utilized different fibrinogen sources and measured tissue reorganization in floating and tensioned collagen lattices. Our results showed that both fibrin and fibrinogen decreased the contraction of fibroblast populated collagen lattices in a dose-dependent manner. Polymerization of fibrinogen to fibrin using thrombin had no effect on this inhibition. Further, there was no effect due to changes in protein concentration, alternate components of the fibrin sealant, or the enzymatic action of thrombin. These results suggest that the initial stability of the fibrin provisional matrix is due to the fibrin, because this protein appears to inhibit contraction of the matrix. This may be important in the early phases of wound healing when clot stability is vital for hemostasis. Later, as fibrin is replaced by collagen, wound contraction can occur. (+info)
(34/341) Midterm clinical and echocardiographic results with patch glue repair of left ventricular free wall rupture.
BACKGROUND: Left ventricular free wall rupture (LVFWR) is a dramatic complication after myocardial infarction. We present our mid-term clinical and echocardiographic results of LVFWR with an epicardial patch without cardiopulmonary bypass. METHODS: From February 1993 to May 2001, 17 patients underwent surgery for LVFWR. The mean age+/-SD of 12 males and 5 females was 68+/-10 years. All patients presented for emergency surgery with cardiac tamponade confirmed on echocardiography. After opening the chest and identification of the site of rupture, a Goretex patch was fashioned and applied with enbucrilate surgical glue. RESULTS: Effective control of bleeding was achieved in all cases. There were no on-table deaths. The operative (30 day) mortality was 23.5% (4/17). One death occurred because of patch failure, two because of cardiogenic shock, and one from pneumonia. On follow-up at a median of 2.2 years (interquartile range, 1.1 to 4.3 years), two further deaths occurred, one from myocardial infarction and another of undetermined etiology. Echocardiography did not reveal any evidence of restriction to left ventricular free wall motion. CONCLUSIONS: Patch glue repair is expedient, simple and effective; with no adverse effects on mid-term ventricular dynamics. In view of superior published results to infarctectomy and repair with extra corporeal circulation, it should be considered to be the initial procedure of choice for the surgical repair of LVFWR. (+info)
(35/341) Technical feasibility of embolizing aneurysms with glue (N-butyl 2-cyanoacrylate): experimental study in rabbits.
BACKGROUND AND PURPOSE: Liquid embolic agents may have potential as a therapeutic option to reconstruct a defective vessel wall. We evaluated the feasibility of transarterial glue embolization in surgically constructed carotid artery aneurysms. METHODS: Reconstruction of arterial wall defects with use of glue casts was performed in 16 surgically constructed aneurysms of carotid arteries in rabbits. Via the transfemoral route, glue was injected without balloon protection through a microcatheter into the aneurysmal sac with (n = 8) and without (n = 8) a framework of coils. To identify safe and effective methods, four concentrations (28%, 33%, 40%, 50%) of glue-iodized oil mixtures were used in four aneurysms each. Immediate (n = 16) and 2-month follow-up (n = 10) postembolization angiograms were obtained to evaluate the residual aneurysmal sac and the carotid artery patency. RESULTS: Continuous column injection of glue was possible in all aneurysms, without fragmented migration of the injected glue cast. Catheter sticking or breakage did not occur during catheter retrieval. Glue embolization without a framework of coils (n = 8) resulted in complete obliteration of the aneurysmal sac in five aneurysms and incomplete obliteration with a small residual lumen in three. Two aneurysms resulted in carotid occlusion after catheter removal. A follow-up angiogram (n = 4) showed decreased residual lumen in two aneurysms, no change in the complete aneurysm occlusion in one, and carotid occlusion in one. Glue embolization with a coil framework (n = 8) resulted in complete obliteration of the aneurysmal sac in six aneurysms and incomplete obliteration with a small residual lumen in two. A small amount of spillage occurred in one owing to the improper position of the microcatheter caused by a difficult neck angle to the parent artery. Follow-up angiograms (n = 6) showed decreased residual lumen in one of two aneurysms and no change of the complete occlusion in five of six aneurysms. CONCLUSION: Effective glue embolization into the aneurysmal sac is technically feasible. Microcatheter position within the aneurysm, concentration of glue, and direction of the aneurysmal neck angle all must be considered. With a coil framework, glue injection was more complete, without deformity or spillage of the glue from the aneurysm. (+info)
(36/341) VASCULAR ANASTOMOSIS--SUTURES, STAPLES OR GLUE?
Different vascular suturing techniques were assessed in the experimental laboratory. Staples made of tantulum wire were employed for vascular anastomoses in normal dogs' arteries and veins and in atherosclerotic rabbits' aortas. The staples were driven with the NRC Vascular Suturing Instrument. In a similar series of experiments a plastic bonding agent (Eastman 910) was used. The anastomosed vessels were found to be patent and few complications were encountered. However, it is unlikely that the conventional suture technique with the currently available materials will be replaced by these methods except under special circumstances. Clinical application of the stapling method is envisaged in the anastomosis of small vessels and in situations when speed is essential, whereas the bonding agent promises to be useful as an ancillary method in combination with sutures or staples. (+info)
(37/341) Initial successful management of type I endoleak after endovascular aortic aneurysm repair with n-butyl cyanoacrylate adhesive.
OBJECTIVE: Transcatheter embolization with coils and other agents has been described as a treatment method for type II endoleak after endovascular aortic aneurysm repair (EVAR). Type I endoleak has not been treated commonly with such therapies, although most investigators believe they warrant definitive intervention. The liquid adhesive n-butyl 2-cyanoacrylate (n-BCA) is often used to treat congenital arteriovenous malformations. The objective of this study is to report our initial experience in treating type I endoleak with n-BCA and with a variety of other interventions. METHODS: A retrospective review was performed of 270 patients who underwent EVAR at our institution between January 1994 and December 2002. Of these, 24 patients had type I endoleak (8.9%), diagnosed either intraoperatively (n = 13, 52%) or during follow-up (n = 12, 48%). Among these 24 patients, 17 had proximal leaks and the remaining 8 patients had distal leaks. These cases form the focus of this study. RESULTS: Twenty-two leaks required endovascular intervention, with the following success rate: n-BCA, 12 of 13 cases (92.3%); extender cuffs, 4 of 5 cases (80%); coils with or without thrombin, 3 of 4 cases (75%). In one patient with persistent endoleak despite attempted endovascular intervention the device ultimately was surgically explanted, and the patient did well. Of six patients with endoleak initially managed expectantly, two eventually underwent attempts at definitive intervention, both with n-BCA. Three sealed spontaneously before definitive intervention could be performed; and in one 97-year-old patient who refused intervention, the aneurysm subsequently ruptured and the patient died. In total, 13 patients with type I endoleak underwent n-BCA transcatheter embolotherapy. No serious complications were directly related to this therapy. Colon ischemia developed in one patient, and was believed to be a result of thromboembolism during wire and catheter manipulation rather than n-BCA treatment. Twelve of these 13 leaks remain sealed at mean follow-up of 5.9 months (range, 0-19 months). CONCLUSION: Our initial use of n-BCA occlusion suggests that it may be an effective and safe method of treatment of type I endoleak after EVAR. In particular, n-BCA embolotherapy may be especially useful in treating type I endoleak not amenable to placement of extender cuffs. Larger case series and longer follow-up are needed before this treatment is more broadly recommended. Type I endoleak after EVAR can be treated successfully with a variety of endovascular methods, and surgical explantation is rarely required. (+info)
(38/341) Surface pretreatments for medical application of adhesion.
Medical implants and prostheses (artificial hips, tendono- and ligament plasties) usually are multi-component systems that may be machined from one of three material classes: metals, plastics and ceramics. Typically, the body-sided bonding element is bone. The purpose of this contribution is to describe developments carried out to optimize the techniques, connecting prosthesis to bone, to be joined by an adhesive bone cement at their interface. Although bonding of organic polymers to inorganic or organic surfaces and to bone has a long history, there remains a serious obstacle in realizing long-term high-bonding strengths in the in vivo body environment of ever present high humidity. Therefore, different pretreatments, individually adapted to the actual combination of materials, are needed to assure long term adhesive strength and stability against hydrolysis. This pretreatment for metal alloys may be silica layering; for PE-plastics, a specific plasma activation; and for bone, amphiphilic layering systems such that the hydrophilic properties of bone become better adapted to the hydrophobic properties of the bone cement. Amphiphilic layering systems are related to those developed in dentistry for dentine bonding. Specific pretreatment can significantly increase bond strengths, particularly after long term immersion in water under conditions similar to those in the human body. The bond strength between bone and plastic for example can be increased by a factor approaching 50 (pealing work increasing from 30 N/m to 1500 N/m). This review article summarizes the multi-disciplined subject of adhesion and adhesives, considering the technology involved in the formation and mechanical performance of adhesives joints inside the human body. (+info)
(39/341) A study to compare a new self-adherent soft silicone dressing with a self-adherent polymer dressing in stage II pressure ulcers.
Pressure ulcers are common among elderly nursing home residents. To be effective in managing these wounds, a dressing should maintain a moist environment, facilitate healing, absorb exudate, remain in place for a number of days, and prevent trauma to the surrounding skin. An 8-week, open, randomized, multicenter, controlled study was conducted to compare the effects of a new self-adherent soft silicone dressing and a self-adherent hydropolymer dressing on Stage II pressure ulcers. Thirty-eight (38) residents participated in the study. Eighteen residents (mean age 83.8 years, range 74.9 to 95.1 years) were randomized to wound management with a soft silicone dressing, and the ulcers of 20 residents (mean age 82.5 years, range 66.4 to 91.9 years) were managed with a hydropolymer dressing. Wound healing, wound and surrounding skin characteristics, and ease of dressing removal were measured and documented. During the study, eight (44%) ulcers in the soft silicone group and 10 (50%) in the hydropolymer dressing group healed. Both dressings were changed approximately once a week and no differences in signs of inflammation, amount of exudate and odor, or incidence of leakage were observed. Damage to the surrounding skin, maceration, and dressing removal difficulties were less common with the soft silicone dressing. Differences in tissue damage between the two dressings were significant during weeks 1, 2, and 3 (P < 0.05). Studies with a larger sample size are needed to confirm these findings. (+info)
(40/341) Effect of several factors on the mechanical properties of pressure-sensitive adhesives used in transdermal therapeutic systems.
The effects of coating thickness, type of adhesive, and type and concentration of enhancer on the mechanical properties of two acrylic pressure-sensitive adhesives (PSAs) were investigated using a 2(4) factorial design and an optimization technique. Sixteen formulations containing 0% or 10% of either caprylic acid or methyl laurate in two different PSAs, namely Duro-Tak 87-2196 and Duro-Tak 87-2097, were prepared. The adhesive properties of these laminates were evaluated by applying the 90 degrees Dynamic Adhesive Strength Peel Test (90 degrees DASPT) and 1800 Release Liner Peel Test (180 degrees RLPT). Coating thickness, concentration of enhancer, and type of adhesive did affect the 90 degrees DASPT. For the 180 degrees RLPT, the most significant factors were coating thickness and concentration of enhancer, with a strong interaction observed between the two. Coating thickness and concentration of enhancer were also used to create mathematical models that correlated these factors with the mechanical properties of the PSAs. For this purpose, the optimization technique 3(2) was applied. It was found that the correlation of the above factors can be adequately described with polynomial equations, which can be used for predicting the mechanical properties of the laminates containing the above PSAs and methyl laurate (0%-10%). (+info)