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PubMed2006

Biocompatibility of bacterial contaminated prosthetic meshes and porcine dermal collagen used to repair abdominal wall defects.

BACKGROUND AND AIMS: A contaminated or infected surgical site is considered a contraindication for the use of the nonabsorbable alloplastic materials employed to repair abdominal wall defects. Therefore, the biocompatibility of new prosthetic materials was investigated. MATERIALS AND METHODS: Meshes measuring 1.5x1.5 cm made of conventional and titanium-coated polypropylene, polyglycol, or porcine dermal collagen were implanted under the abdominal wall of 96 rats (eight groups of 12 animals each) employing the inlay technique. Implantation of all four materials was performed both under semisterile conditions and bacterial contamination of the mesh. The meshes were explanted after 28 days. RESULTS: All the materials implanted under semisterile conditions were incorporated into the abdominal wall with only few intraabdominal adhesions (mean adhesion scores: 1.0, 1.2, 1.0, 0.8 points, respectively, not significant). With the porcine dermal collagen, proliferation rate and the proportion of inflammatory cells were statistically lower (p<0.01). In the bacterial contamination group, all meshes were associated with a suppurating infection and strong adhesions between the bowel and mesh, which were most prominent in the case of dermal collagen (mean adhesion scores: 1.6, 1.7, 1.7, and 1.9 points, respectively, not significant). In this group, two animals died of peritonitis. In comparison with the other materials, the proliferation rate was significantly elevated (p=0.03). No significant differences were seen between the other materials employed. CONCLUSION: Irrespective of the material employed, implantation of alloplastic meshes in an abdominal wall contaminated with bacteria, is associated with suppurating infections, in particular in the case of the membrane-like porcine dermal collagen. Nonabsorbable alloplastic meshes and dermal skin grafts should therefore not be used to repair infected abdominal wall defects.

Abdominal Wall↗

PubMed2001

Endoscopic augmentation of the cardia with a biocompatible injectable polymer (Enteryx) in a porcine model.

BACKGROUND: Endoscopic approaches to restore the gastroesophageal barrier in patients with gastroesophageal reflux disease (GERD) are presently undergoing clinical trial. The aim of the study was to demonstrate the feasibility, durability, safety, and antireflux efficacy following augmentation of the cardia with a biocompatible injectable polymer (Enteryx). METHODS: Augmentation was performed in 12 Yucatan mini-pigs. The cardia was injected circumferentially with 1-1.5 ml of Enteryx at three or four sites. Four groups of three animals each were killed at 2, 6, 12, and 24 weeks following augmentation. Gastrointestinal endoscopy and esophageal manometry were performed preoperatively and postoperatively. Competency was determined as the intragastric pressure (yield pressure) and volume (yield volume) needed during gastric distension with air and water to result in equalization of gastric and esophageal pressure. Comparisons were made with a group of noninjected animals (n = 6). RESULTS: All animals had a normal eating pattern; none showed any evidence of vomiting or regurgitation. The median injection volume was 4 ml (range, 1-8). At autopsy, implants were found in 83% of the animals. Intramuscular placement of the implant was durable, whereas sloughing occurred if the implant was placed submucosally. The mechanical properties of sphincter length and pressure were unaffected by the injection. The median yield pressure of the animals that survived for >6 weeks (21.4 mmHg) was significantly greater (p = 0.049) than the animals that survived for <6 weeks (4.5 mmHg) and greater (p = 0.054) than the control animals (9.1 mmHg), suggesting that the healing process was associated with reduced distensibility of the cardia. CONCLUSIONS: Augmentation of the cardia with an injectable polymer (Enteryx) is simple, safe, and durable. Early studies suggest that alteration in the distensibility and geometry of the gastroesophageal junction may provide antireflux protection.

Animals↗

PubMed1998

Results of the biocompatible osteoconductive polymer (BOP) as an intersomatic graft in anterior cervical surgery.

Eighty-two patients operated on in our Department between 1989 and 1995 with an anterior cervical approach for soft and hard cervical disc herniations and cervical stenosis were included in this study. In 41 cases a heterologous intersomatic bovine graft (Surgibone) was used. Another 41 patients underwent surgery with a biocompatible osteoconductive polymer (BOP) as intervertebral graft. Both groups were retrospectively reviewed and compared with the objectives of evaluating the biodynamic behaviour of the grafts in the intersomatic space, the complications which appeared (specially those related to the grafts), the bone fusion rate achieved and the clinical outcome of the patients. The results of our study show that the BOP group presented a higher tendency to intersomatic space collapse 6 months after discectomy. There were no differences in the general surgical complications between both groups, but those related directly to the graft were significantly higher in the BOP group. The vast majority of the graft complications recorded had no clinical correlation. Without a strict radiological follow-up such complications would never have been discovered. Bone fusion in the BOP group was significantly slower and worse. Finally, the clinical outcome in both groups did not show any significant difference.

Animals↗

PubMed2001

The influence of differing pore sizes on the biocompatibility of two polypropylene meshes in the repair of abdominal defects. Experimental study in dogs.

Two types of monofilament polypropylene meshes of markedly different construction, configuration and pore size were compared and used to repair full-thickness muscle defects in the abdominal wall of 22 mongrel dogs to assess their biocompatibility with host tissues. The defects were repaired with Prolene (Ethicon) woven mesh (pore size = 164 x 96 microns) and with an experimental, extruded mesh called T mesh (pore size = 3 mm x 4 mm). On the 30th postoperative day, the animals were sacrificed, and the segments of the abdominal wall containing the implanted meshes were excised. Although the Prolene mesh had greater tensile strength before implantation, 30 days after implantation, the T mesh showed similar tensile strength to Prolene mesh. The collagen densitometry showed a significant increase of total and mature collagen type I deposition in the T mesh. This suggests that the increased mature collagen type I deposition significantly increases the tensile strength of the reinforced mesh tissue and that the larger pore in the T mesh contributed to this finding by allowing increasing fibber orientation within the pores as a result of in vivo tension.

Abdominal Muscles↗

PubMed2003

Clinical study of biocompatibility between open and closed heparin-coated cardiopulmonary bypass circuits.

The objective of this study was to investigate the difference between the closed circuit system and the open circuit system in clinical heparin-coated cardiopulmonary bypass (CPB) circuits with a centrifugal pump. We evaluated the coagulation, fibrinolysis, and inflammatory response in valvular heart surgery. Nineteen patients were assigned at random to a group for the closed circuit system or the open circuit system. This is the first report on the effect of a closed circuit in valvular surgery. We measured the platelet count, white blood cell count, plasma fibrinogen concentration, thrombin-antithrombin III complex, plasmin-Alpha2 plasmin inhibitor complex, D-dimer, interleukin-6, polymorphic neutrophil-elastase, and the plasma free hemoglobin. Blood samples were collected before the start of perfusion, 15 and 60 min after the start of perfusion, 60 min after the administration of protamine, and 1 day after the operation. During the perfusion, coagulation, fibrinolysis, and inflammatory responses were activated; however, no significant differences between the two groups were noted. In this clinical investigation with suction and the cell saving system, the closed circuit was not found to be superior to the open circuit with regard to biocompatibility.

Aged↗

PubMed2005

Physical properties and biocompatibility of chitosan/soy blended membranes.

Blends of polysaccharides and proteins are a source for the development of novel materials with interesting and tailorable properties, with potential to be used in a range of biomedical applications. in this work a series of blended membranes composed by chitosan and soy protein isolate was prepared by solvent casting methodology. in addition, cross-linking was performed in situ with glutaraldehyde solutions in the range 5x10(-3)-0.1 M. Furthermore, the influence of the composition and cross-linking on the degradation behaviour, water uptake and cell adhesion was investigated. The obtained results showed that the incorporation of chitosan, associated to network formation by cross linking, promoted a slight decrease of water absorption and a slower degradability of the membranes. Moreover, direct contact biocompatibility studies, with L929 cells, indicate that the cross-linking enhances the capability of the material to support cell growth.

Absorbable Implants↗

PubMed2005

Comparison of microstructural evolution in Ti-Mo-Zr-Fe and Ti-15Mo biocompatible alloys.

The microstructural evolution and attendant strengthening mechanisms in two biocompatible alloy systems, the binary Ti-15Mo and the quaternary Ti-13Mo-7Zr-3Fe (TMZF), have been compared and contrasted in this paper. In the homogenized condition, while the Ti-15Mo alloy exhibited a single phase microstructure consisting of large beta grains, the TMZF alloy exhibited a microstructure consisting primarily of a beta matrix with grain boundary alpha precipitates and a low volume fraction of intra-granular alpha precipitates. On ageing the homogenized alloys at 600 degrees C for 4 h, both alloys exhibited the precipitation of refined scale secondary alpha precipitates homogeneously in the beta matrix. However, while the hardness of the TMZF alloy marginally increased, that of the Ti-15Mo alloy decreased substantially as a result of the ageing treatment. In order to understand this difference in the mechanical properties after ageing, TEM studies have been carried out on both alloys in the homogenized and homogenized plus aged conditions. The results indicate that the omega precipitates dissolve on ageing in case of the Ti-15Mo alloy, consequently leading to a substantial decrease in the hardness. In contrast, the omega precipitates do not dissolve on ageing in the TMZF alloy and the precipitation of the fine scale secondary alpha leads to increased hardness.

Alloys↗

PubMed2006

Silicone based polyurethane materials: a promising biocompatible elastomeric formulation for cardiovascular applications.

The biocompatibility of a new material for cardiovascular applications constituted by a poly(ether)urethane (PEtU) and a silicone [polydimethylsiloxane (PDMS)] was evaluated. The achieved material shows properties similar to both polyurethanes and silicones. The material was transformed into porous membranes by a spray-deposition technique. Since any material preparation and manufacturing procedure may introduce some toxicity, in vitro cytotoxicity screening tests were carried out. Human umbilical vein endothelial cells (HUVECs) and a mouse fibroblasts cell line (L929) were cultivated with extracts obtained from materials containing 10, 40 and 100% (w/w) of PDMS. The commercially available Estane 5714-F1 and Cardiothane 51 were used as controls. Extracts were incubated up to 72 hours with HUVECs and L929 cells. The cytotoxic effect was evaluated by light microscopy, cell viability (MTT reduction and neutral red uptake) and proliferation (5-bromo-2'-deoxyuridine incorporation) tests. In vivo studies were carried out using materials containing the same PDMS percentages as for in vitro experiments. The same commercial controls were used. Results obtained with cell culture studies agreed with those obtained in the in vivo experiments and showed that the material preparation and manufacturing procedure do not introduce any toxicity in the products at each PDMS concentration investigated.

Animals↗

PubMed1996

Centrifugal pump and heparin coating improves cardiopulmonary bypass biocompatibility.

BACKGROUND: Centrifugal pumps are being used increasingly for short-term extracorporeal circulation purposes such as during heart operations. Whether the centrifugal pump improves the cardiopulmonary bypass biocompatibility has not been fully documented. METHODS: A roller pump (n = 20) was compared in vivo with a centrifugal pump (n = 20) in groups of patients in which cardiopulmonary bypass circuits that were either totally heparin coated (Carmeda BioActive Surface; n = 20) or uncoated (n = 20) were used. We expected the heparin coating to attenuate blood activation, thus possibly making the comparison of the two pumps easier with respect to their different blood activation potentials. Samples of blood plasma, obtained during cardiopulmonary bypass from low-risk coronary artery bypass grafting patients, were analyzed for hemolysis (plasma haemoglobin), complement activation (C3bc and the terminal complement complex), a complement lytic inhibitor (vitronectin), coagulation activation (fibrinopeptide A), granulocyte activation (lactoferrin), and platelet activation (beta-thromboglobulin). RESULTS: The concentrations of terminal complement complex, lactoferrin, and beta-thromboglobulin were significantly lower in association with heparin-coated surfaces. The concentration of plasma hemoglobin was significantly lower in association with the centrifugal pump. In uncoated circuits, the beta-thromboglobulin level was significantly higher in association with the roller pump than with the centrifugal pump, but this significant reduction in the beta-thromboglobulin level did not hold true for the heparin-coated circuit group. CONCLUSIONS: A heparin-coated cardiopulmonary bypass surface reduces the blood activation potential during cardiopulmonary bypass, and the centrifugal pump causes less hemolysis than the roller pump.

Adult↗

PubMed1987

Interactions of polymerizable phosphatidylcholine vesicles with blood components: relevance to biocompatibility.

We have studied the biocompatibility properties of polymerizable phosphatidylcholine bilayer membranes, in the form of liposomes, with a view toward the eventual utilization of such polymerized lipid assemblies in drug carrier systems or as surface coatings for biomaterials. The SH-based polymerizable lipid 1,2-bis[1,2-(lipoyl)dodecanoyl]-sn-glycero-3-phosphocholine (dilipoyl lipid, DLL) and the methacryl-based lipid 1,2-bis[(methacryloyloxy)dodecanoyl]-sn-glycero-3-phosphocholine (dipolymerizable lipid, DPL) were studied in comparison to 'conventional' zwitterionic or charged phospholipids. We examined binding of serum proteins to liposomes and effects of liposomes on fibrin clot formation and on platelet aggregation. All types of liposomes tested bound complex mixtures of serum proteins with IgG being the most abundant bound component. DPL vesicles and anionic vesicles bound substantially more protein than other vesicle types. Polymerized DPL vesicles uniquely bound a protein of about 53 kDa which was not bound to other types of phosphatidylcholine liposomes. Likewise polymerized DPL vesicles, but not other types of phosphatidylcholine vesicles, caused a marked alteration in coagulation as measured by activated partial thromboplastin time (APTT) and prothrombin time (PT) tests; this effect was shown to be due to binding and depletion of clothing factor V by the DPL polymerized vesicles. Polymerized DPL liposomes and DLL liposomes in polymerized or nonpolymerized form, were without substantial effect on platelet aggregation. However, DPL nonpolymerized vesicles, while not causing aggregation, did impair ADP-induced aggregation of platelets. These studies suggest that SH based polymerizable lipids of the DLL type may be very suitable for in vivo use in the contexts of drug delivery systems or biomaterials development. Methacryloyl-based lipids of the DPL type seem to display interactions with the hemostatic process which militate against their in vivo utilization.

Biocompatible Materials↗

PubMed1995

Biocompatibility of polymer-coated oversized metallic stents implanted in normal porcine coronary arteries.

Polymer coatings have been suggested to decrease the thrombogenicity of metallic intravascular stents. The purpose of the present study was to investigate the intimal response to two different polymers when used as coatings for stents implanted in normal porcine coronary arteries. Non-articulated stainless steel-slotted tube stents were coated with either a biodegradable poly(organo)phosphazene with amino-acid ester side groups or a biostable polyurethane prepared from an amphiphilic polyether, dephenylmethane-4,4'-diisocyanate and butane diol as chain extender. In order to induce vascular wall injury, the stents were deployed using an oversized balloon. At 6 weeks follow-up, the angiographic luminal diameter measured in four polyurethane-coated stents and in six bare metallic stents was similar and 20% less than immediately post-stenting. However, in four polyphosphazene-coated stents the difference was 65% (P = 0.01 when compared to bare metal). At post-mortem morphometry the degree of luminal area stenosis was also similar in polyurethane-coated and in bare metallic stents (32 +/- 7.6% vs. 39 +/- 14%, NS) but reached 81 +/- 19% in polyphosphazene-coated stents (P < 0.03 when compared to bare metal). Thus, poly(organo)phosphazene induced a more pronounced histiolymphocytic and fibromuscular reaction than amphiphilic polyurethane, which appeared to be promising as biocompatible stent coating and, consequently, as a potential carrier for vasoactive drugs.

Animals↗

PubMed1979

Biocompatibility evaluation of casting alloys in hamsters.

A number of base metal and low gold-content alloys were evaluated in hamster cheek pouches for biocompatibility. No adverse weight changes and no abnormal behavioral patterns were noted in any of the test groups over the 14-day period of the study. Gross examination of the cheek pouches containing the alloys was no different from that of the controls. None of the alloys tested showed significant adverse histopathologic reactions. The recorded changes in incidences and degree of response were essentially no different from those of the negative control material.

Animals↗

PubMed1994

Biocompatibility of visible light-cured resin systems in prosthodontics.

Frequently dental products are introduced that have had little or no biologic testing. Cell culture systems that traditionally have been used for the study of cellular responses have recently been used to assess biocompatibility. This article reviews various cellular toxicity assays and their application to the resin systems used in clinical prosthodontics.

Acrylic Resins↗

PubMed1979

Clinical use of biocompatible ultrasonic bladder volume sensor.

A biocompatible ultrasonic bladder volume sensor has been developed and successfully employed to sense bladder fullness in healthy volunteers. It is anticipated that it will be of practical use in patients with diabetic autonomic neuropathy as well as in patients employing self-intermittent catheterization.

Biocompatible Materials↗

PubMed1982

Biocompatibility screening of poly (vinyl chloride) implants.

It was proposed to test the biocompatibility of a polymeric implant by assaying enzyme activity in the tissue homogenate. Medical grade poly(vinyl chloride) was implanted in rat gluteal muscle and muscle specimens taken from the implanted and non-implanted sites after 7, 14 and 21 days. In the muscle homogenate taken in suitable solvents, the activities of alkaline phosphatase, acid phosphatase, Ca2+ ATPase, leucine aminopeptidase (LAP) and succinic dehydrogenase (SDH) were tested and compared at implanted and non-implanted sites. Increased activity of acid phosphatase, alkaline phosphatase, LAP and Ca2+ ATPase were seen at the implanted site but the SDH activity was reduced. The enzyme activity at both sites was maximum around 14 days and the highest increase in activity at the implant site compared to the control site was observed for alkaline phosphatase and acid phosphatase. After 21 days, the activity decreased gradually. In case of SDH, the inhibition was more after 14 days and gradually decreased after 21 days.

Acid Phosphatase↗

PubMed1984

Biomaterial biocompatibility and the macrophage.

The biocompatibility of biomaterials at implant sites is controlled by the tissue/material interaction. A major cell in the tissue reaction is the macrophage. A summary is presented on macrophage mediation of cellular and humoral regulatory pathways in inflammatory and immune responses.

Biocompatible Materials↗

PubMed1987

Biocompatibility and degradability of sepiolite-collagen complex.

Sepiolite, a magnesium silicate, binds collagen resulting in a complex which has a gel-like structure when hydrated. The binding of the protein to the clay decreases its degradability by collagenase, and no degradation was observed after treatment of the complex with glutaraldehyde. Extracts of both the untreated and the glutaraldehyde-treated complex are biocompatible for fibroblast growth. Based on its properties, this material should be considered in the design of biomaterials.

Biocompatible Materials↗

PubMed1987

Mechanical properties and biocompatibility of two polyepoxy matrices: DGEBA-DDM and DGEBA-IPD.

The aim of this paper was to study the biocompatibility and mechanical properties of materials for orthopaedic and odontologic surgical use. The products used were obtained by polycondensation of a diepoxy resin (DGEBA) with two curing agents (DDM or IPD). The materials present a slight swelling in liquid medium and their thermomechanical properties are hardly affected after 12 month implantation. The absence of molecular desorption in isotonic liquid and human serum confirms their hydrolytic stability and thus their inertia. These materials do not give rise to an intolerance reaction by neighbouring tissues during implantation time (1 d to 12 month).

Aniline Compounds↗