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PubMed1989

Improved biocompatibility by modified cellulosic membranes: the case of hemophan.

The rising problem of biocompatibility is encouraging the development of new dialysis membranes, but the high cost of synthetic ones precludes their wide use. The authors compared the biocompatibility of cuprophan (CU), cellulose acetate (CA), and hemophan (HE), evaluating both in vitro and in vivo polymorphonuclear leukocyte (PMN) oxidative metabolism activation by resting chemiluminescence and complement activation by C3a; in vivo PMN counts during dialysis were also performed. The lowest increase in in vitro PMN resting chemiluminescence using HE was + 71.3% with CA, +49.3% with CU, and + 21.4% with HE (p less than 0.001 versus CA and CU); furthermore, HE did not significantly stimulate PMN resting chemiluminescence during in vivo hemodialysis: + 56.6% with CA, + 38.8% with CU, and + 3.7% with HE (p less than 0.01 versus CU and p less than 0.001 versus CA). C3a concentration increased with all membranes both in vitro and in vivo, but HE (in both experimental conditions) showed the lowest increase at any time (p less than 0.001 versus CA and CU). After 15 min of dialysis, PMN count dropped to 20.3% of basal values with CU, to 49.8% with CA, and to 76.5% with HE (p less than 0.001 versus CU and CA). Among cellulosic membranes, HE is the most biocompatible and appears to be an important step in preventing blood-membrane interactions and related complications.

Biocompatible Materials↗

PubMed1993

Biocompatibility of leukocyte removal filters during leukocyte filtration of cardiopulmonary bypass perfusate.

To evaluate the biocompatibility and the efficacy of leukocyte removal filters, we performed a prospective study by using the cardiopulmonary bypass perfusate taken from the heart-lung machine for 20 patients who underwent cardiac surgery and were randomly divided into four groups according to the filters used. A leukocyte removal filter was installed in the transfusion line while the perfusate was transfused to the patients. No increases of C3a, C5a, elastase, and thromboxane were found during leukocyte filtration by polyester filters (Optima, Sepacell R500, and Pall RC100). Activation of the complement cascade was observed during filtration by the cellulose acetate filter (Cellselect) although the efficacy of the Cellselect filter was evidently higher than that of the polyester filter. These results imply that polyester leukocyte filters are superior to cellulose acetate filters in terms of biocompatibility but have a reduced efficacy. An optimal leukocyte filter providing both high efficacy and biocompatibility has yet to be developed.

Biocompatible Materials↗

PubMed1997

LDL hemoperfusion--a new procedure for LDL apheresis: biocompatibility results from a first pilot study in hypercholesterolemic atherosclerosis patients.

Current lipid apheresis techniques can remove atherogenic lipoproteins only from plasma. The initial mandatory separation of plasma and blood cells renders the extracorporeal circuit complex. We recently described the first clinical application of a new lipid adsorber that adsorbs low-density lipoprotein (LDL) and lipoprotein (a) (Lp[a]) directly from whole blood. In continuation of our work, this paper describes the clinical biocompatibility of this new LDL hemoperfusion system. In a 2 center phase II clinical trial, 12 hypercholesterolemic patients suffering from overt coronary or peripheral artery disease were treated once with LDL hemoperfusion. The new LDL adsorber (DALI, Fresenius, St. Wendel, Germany) contained 480 ml of polyacrylate coated polyacrylamide gel. The anticoagulation protocol consisted of an initial heparin bolus followed by an acid citrate dextrose-A (ACD-A) infusion during the treatment. One patient blood volume was treated per session. All sessions were clinically uneventful. No signs of hemolysis or extracorporeal clot formation could be detected, and cell counts remained virtually constant. In a subgroup of patients (n = 4-6), further biocompatibility parameters were studied. Activation of leukocytes (elastase release), thrombocytes (beta-thromboglobulin [beta-TG] extrusion), and monocytes (interleukin (IL)-1beta and IL-6) were minimal. Complement activation (C3a and C5a generation) was negligible. The chosen anticoagulation protocol was both safe (constant ionized calcium levels) and effective (low thrombin-antithrombin formation). In summary, within the scope of a first pilot study, this new LDL hemoperfusion procedure combined the features of excellent clinical tolerance, good biocompatibility, and ease of handling. Phase III clinical trials will have to show whether these encouraging preliminary results can be corroborated in a larger patient population.

Acrylic Resins↗

PubMed2005

Corrosion resistance and biocompatibility of a new porous surface for titanium implants.

Alterations of the commercially pure titanium (cpTi) surface may be undertaken to improve its biological properties. The aim of this study was to investigate the biocompatibility of cpTi when submitted to a new, porous titanium, surface treatment (porous Ti). Five types of surface treatments, namely sintered microspheres porous titanium (porous Ti), titanium plasma spray (TPS), hydroxyapatite (HA), sandblasted and acid etched (SBAE), and resorbable blast medium, sandblasted with hydroxyapatite (RBM) were made. In the experimental methods, the corrosion potentials were measured over time, and then a linear sweep voltammetric analysis measured the polarization resistances and corrosion currents. For biocompatibility evaluation, MG63 osteoblast-like cells were used. Cell morphology, cell proliferation, total protein content, and alkaline phosphatase (ALP) activity were evaluated after 2 h, and after 2, 4 and 7 d. Porous Ti and SBAE showed a better corrosion resistance, with a weak corrosion current and a high polarization resistance, than the other surfaces. Cell attachment, cell morphology, cell proliferation, and ALP synthesis were influenced by the surface treatments, with a significant increase observed of the activity of osteoblast cells on the porous coating (porous Ti). Based on these results, it is suggested that the porous Ti surface has a significantly better biocompatibility than the other surface treatments and an excellent electrochemical performance.

Analysis of Variance↗

PubMed2001

Biocompatibility of root canal filling materials.

Results of in vitro and in vivo studies clearly indicate that some endodontic sealers may cause local and systemic adverse effects. Though occasionally contradictory data has been reported from various authors, it may be concluded that zinc-oxide-eugenol sealers possess a marked cytotoxic and tissue-irritating potency. Most Ca(OH)2-based materials, however, were biocompatible. Genotoxic effects have been observed with sealers releasing paraformaldehyde or containing mutagenic substances, such as bisphenol-A-diglycidyl-ether or its derivatives. It cannot be excluded that these materials may pose a systemic risk because formaldehyde is rapidly distributed systemically following its application into the pulp cavity. Furthermore an increasing number of cases with an aspergillosis of the maxillary sinus have been observed which were mainly caused by zinc-releasing endodontic sealers. Overall, it is recommended that for endodontic practice, sealers that have been found to be biocompatible in a "mixed bag" of various in vitro and in vivo tests, be selected. From this point of view, ZnOE-sealers should no longer be used for root canal fillings. This recommendation applies also to sealers containing paraformaldehyde or generating this substance during their setting reaction. More experimental and clinical studies are necessary to elucidate whether new materials, such as mineral trioxide aggregate (MTA) or calcium phosphate cement, will be biocompatible alternatives in the future.

Animals↗

PubMed2006

Biocompatibility of septal defect closure devices.

OBJECTIVE: Despite their clinical introduction 10 years ago, no human series on the healing response to Amplatzer and Starflex devices in humans have been reported yet. We sought to investigate the biocompatibility of Amplatzer and Cardioseal/Starflex septal occluder devices in humans and compare the findings to results in experimental animals. METHODS: The healing response of Amplatzer and Cardioseal/Starflex septal occluder devices in humans (n = 12, follow-up periods from 5 days to 4 years) and in experimental animals (n = 32, follow-up periods from 4 days to 1 year) was studied using a uniform work up protocol. Histological sections of paraffin-wax-embedded or methacrylate-embedded specimen and scanning electron microscopy were used for biocompatibility screening. RESULTS: Neoendothelialisation of all examined devices was complete after 3 months in vivo. Protruding metal frame parts, like screw threads and spring arms, were covered last. The initial deposition of fibrin and blood cells on the polyester fabric was subsequently organised by ingrown fibroblastic cells. Loosely arranged and poorly vascularised young granulation tissue was transformed time-dependently into quiescent fibre-rich connective repair tissue poor of cellular and capillary vessel components. Consistently, a mild chronic inflammatory response directed against textile fibres of both types of implants characterised by lymphocytic infiltration and multinucleated foreign body giant cells was observed equally in human and animal explants. CONCLUSIONS: Systematic biocompatibility screening in a series of explanted human septal occluder devices showed results corresponding to findings in animal studies with regard to neoendothelialisation, cellular organisation of initial thrombus and persisting immune response.

Animals↗

PubMed1997

Acute renal failure: role of dialysis membrane biocompatibility.

Recent clinical studies of acute renal failure in adults have focused attention on the biocompatibility of the dialysis membrane as a possible factor influencing patient morbidity and mortality. In this article, we review the concept of dialysis membrane biocompatibility and highlight the difficulty of finding an ideal definition. We then expand on the possible roles of complement and neutrophil activation by dialysis membranes, which may prolong the recovery from acute renal failure. The results of several clinical studies analyzing the impact of dialysis membranes on the course and outcome of acute renal failure are discussed. Finally, the possible relevance of biocompatibility in continuous renal replacement therapies is emphasized.

Adult↗

PubMed2000

Bovine type I collagen as an endovascular stent-graft material: biocompatibility study in rabbits.

PURPOSE: To study the biocompatibility of a bovine type I collagen preparation as a material for small-vessel stent-grafts in rabbits. MATERIALS AND METHODS: A composite nitinol-collagen endovascular stent-graft with a 4-mm inner diameter was deployed in the abdominal aorta in nine rabbits. Angiography was performed, and the rabbits were sacrificed at 1, 2, and 7 days and at 1 and 3 months. The portion of the aorta containing the stent-graft was excised and was histologically evaluated. RESULTS: All stent-grafts were patent at all time points. On days 1, 2, and 7 after implantation, scattered red and white blood cells adhered to the stent-graft. At 1 month, the stent-graft was endothelialized and was infiltrated with fibroblasts that deposited collagen within the interstices of the implanted collagen material. At 3 months, there was additional collagen deposition within the interstices of the stent-graft that did not narrow the lumen of the stent-grafts. CONCLUSION: Type I collagen as a intravascular stent-graft material is biocompatible for at least 3 months in rabbits. It is rapidly endothelialized and does not cause reactive stenosis. As a versatile and biocompatible polymer, collagen is potentially useful in the construction of endovascular stent-grafts for use in human arteries.

Alloys↗

PubMed1998

Biocompatibility differences with respect to the dialyzer sterilization method.

The impact of the method of sterilization (steam vs. ethylene oxide, ETO) on indices of biocompatibility is investigated using polysulfone membranes. Eight patients were treated with a random choice of the high-flux membranes F60S (steam) and F60 (ETO) and the low-flux membrane F6 (ETO). Blood samples were taken prior to and 5, 15, 30, 60, and 180 min after the start of hemodialysis. White blood cell count, platelet count, and plasma concentrations of polymorphonuclear neutrophil elastase, complements C3a and C5a, and beta2-microglobulin were determined. The dialysis procedure was associated with a significant decrease in white blood cell count and beta2-microglobulin level and a significant increase in polymorphonuclear neutrophil elastase and complement C3a and C5a levels. However, the steam-sterilized F60S membrane had a significantly lower impact on the biocompatibility indices than the ETO-sterilized F60 and F6 membranes (p < 0.05 or p < 0.001 for the individual markers). We conclude that using steam instead of ETO for sterilization may improve the biocompatibility of membranes.

Adult↗

PubMed2003

Recent concepts in the molecular biology of the peritoneal membrane - implications for more biocompatible dialysis solutions.

This paper reviews some important recent findings on the molecular biology of the peritoneal membrane. It attempts to correlate in vitro and in vivo experimental results with the possible clinical consequences. The most common functional alteration during long-term CAPD is increased peritoneal small-solute transport rate, resulting in impaired ultrafiltration and decreased dialysis efficiency. This contribution first discusses the most relevant advances in the biochemistry and molecular biology of the peritoneal membrane following peritonitis and as consequence of the continuous exposure to unphysiological dialysis fluids. In a second part the preliminary experimental and clinical experience with more biocompatible fluids is summarized. The most relevant structural and functional alterations of the membrane following repeated peritonitis is the consequence of the response of the peritoneum to infective organisms involving the inflammatory cytokines and the interaction between membrane resident cell populations: macrophages, mesothelial cells and fibroblasts. In this setting, human biopsy studies and animal experiments have identified an increase in the peritoneal-associated vasculature, which seems to be the primary cause of increased solute transport. The structural and functional alterations in the membrane in long-term peritoneal dialysis are thought to be the consequence of the toxicity of glucose, either directly or indirectly through the generation of glucose degradation products or the formation of advanced glycation end-products. In particular, an important role for vascular endothelial growth factor and nitric oxide as downstream mediators of the alterations has been suggested. Finally, the last part of this paper reviews the actual and future research aimed at an amelioration of the biocompatibility of the dialysis fluids. Replacing glucose by other osmotic agents, changing the sterilization process, replacing the lactate buffer by bicarbonate, blocking the formation of reactive carbonyl products and of the neoangiogenesis are the most promising changes to enhance the biocompatibility. Finally, gene therapy may in the future have an important contribution. Ex vivo gene therapy involves harvesting peritoneum samples to isolate mesothelial cells that will be genetically modified before re-implantation into the peritoneal cavity.

Animals↗

PubMed1986

Performance and biocompatibility of a new hemodialysis membrane.

Performance studies and investigations of the biocompatibility of a new hemodialysis membrane were conducted in patients being chronically hemodialyzed. The investigated polycarbonate membrane revealed a very satisfying performance with regard to clearance values and the ultrafiltration rate. The biocompatibility studies showed a significant leukopenia and an increase of C5a, platelet factor 4 and granulocyte elastase. Thrombocytes and C3d remained unchanged. Long-term studies have to confirm whether or not the new membrane is more biocompatible, a suggestion which could be advanced, as no febrile episodes were observed during any treatment, a finding which is not typical for Cuprophan hemodialysis.

Biocompatible Materials↗

PubMed1987

Biocompatibility of artificial organs: an overview.

Papers that are presented in this symposium on biocompatibility of foreign surfaces used in artificial organs are commented upon and set in an overall context of the biocompatibility of foreign surfaces to blood. A working formulation of the events comprising lack of biocompatibility of hemodialysis membranes to the complement system is given as a possible model to which other foreign surfaces may be compared.

Animals↗

PubMed1988

Good biocompatibility of the polyamide hemofilter.

Chronic hemofiltration (HF) is now a well-established method, especially for elderly uremic patients and those suffering from cardiovascular problems. This is due to the fact that chronic HF offers superior treatment comfort with less hypotensive episodes, vomiting, muscle cramps and febrile reactions. Apart from the different blood purification techniques involved in chronic HF compared to hemodialysis (i.e. convection versus diffusion), it might well be that the better treatment comfort is attributable to a certain extent to the polyamide HF membrane used in our HF treatments. We studied different biocompatibility parameters and received the following data: (a) leukocytes and thrombocytes remained unchanged during a treatment session; (b) elastase increased slightly but there was no difference between the polyamide and polycarbonate membrane, and (c) arterial and venous concentrations of C5a and C3d remained almost unchanged. The superior treatment comfort and better vascular stability of HF over hemodialysis might also be due to the improved biocompatibility of the applied hemofilter as the polyamide membrane induces no changes in different biocompatibility parameters such as leukocytes, thrombocytes, C5a or C3d.

Biocompatible Materials↗

PubMed2001

Polyamide 6 composite membranes: properties and in vitro biocompatibility evaluation.

The aim of the present study was to develop polyamide 6 membrane blended with gelatin and chondroitin sulfate using the phase precipitation method and evaluate its in vitro biocompatibility. Morphology of membranes was studied by laser scanning confocal microscopy which allowed the nondestructive visualization of internal bulk morphology of membranes. Membranes exhibited porous morphology with pores spanning across the membrane width with interconnections at various depths. Membranes showed adequate mechanical properties with tensile strengths of 20.10 +/- 0.64 MPa, % strain of 3.01+/-0.07, and modulus of 1082.50+/-23.50 MPa. In vitro biocompatibility of membranes by direct contact test did not show degenerative effects on NIH3T3 cells and also its leach-out products (LOP), as determined by tetrazolium (MTT) and neutral red uptake (NRU) assay. Mouse peritoneal macrophage cultured in contact with membranes and PTFE control showed comparable expression of activation markers such as CD11b/CD18, CD45, CD14, and CD86 suggesting the membranes' non-activating nature. Membrane LOP did not induce excessive proliferation of mouse splenocytes suggesting its non-antigenic nature. Preliminary blood compatibility of membranes was observed with no detectable hemolysis in static incubation assay. Taken collectively, the present data demonstrate that polyamide 6 composite membranes are biocompatible and prospective candidates for tissue engineering applications.

3T3 Cells↗

PubMedDate not supplied

Chemical and physicomechanical aspects of biocompatible orthopaedic polymer (BOP) in bone surgery.

The properties of biocompatible orthopaedic polymer developed as an alternative to the metallic materials used in reconstructive bone surgery are discussed. Experiments were conducted to enhance the mechanical characteristics of the polymer by incorporation of various fibres. The result was a super biocompatible orthopaedic polymer which could be a valuable alternative to intra-medullary long bone metallic rods, whilst normal biocompatible orthopaedic polymer is currently used for bone filling and reconstructive surgery.

Biocompatible Materials↗

PubMed2003

Ex vivo biocompatibility of a new beta2-microglobulin hemoperfusion polymer.

Beta2-microglobulin (beta2-m) is an 11.8 kD protein that is excreted by the kidneys. In renal insufficiency, it accumulates in the body and can result in AB amyloidosis with bone and joint destruction. Four modifications of a new beta2-m adsorbent material were tested for biocompatibility with human whole blood. 500 ml of heparinized blood from healthy human donors was perfused ex vivo through minicolumns (adsorber beads: divinylbenzene with different biocompatible coatings) in the single-pass mode. Blood samples were taken from the antecubital vein before and at the column outlet during the 50 min test runs. Red and white cell counts remained virtually constant. No signs of hemolysis could be detected. Thrombogenicity of the columns was low as shown by the insignificant platelet loss, only slight platelet activation and moderate thrombin-antithrombin formation. There was no activation of leukocytes nor monocytes. Complement and bradykinin activation was minimal. Electrolyte concentrations and pH remained essentially constant. In conclusion, this new beta2-m adsorbent material exhibited favorable biocompatibility features in our ex vivo model and is thus a promising candidate for future clinical beta2-m hemoperfusion studies in patients.

Antithrombin III↗

PubMed1987

Biocompatible resins in dentistry.

The evolution of treatment for dental disease has been keyed to developments in technology. Once the diseased tooth structure was removed, various materials were then utilized to restore health and function to the tooth. A major consideration must be the biocompatibility of the restorative materials--both to the vital process of the tooth, as well as the oral cavity. It has been generally accepted that calcium hydroxide containing products are the materials of choice to be placed in direct contact with the pulp, prior to placement of these restorative materials. As the demands on restorative materials became more defined, the requirements of the base materials also became greater. Due to the numerous desirable features of polymeric resins, the search for a biocompatible resin base system incorporating calcium hydroxide was initiated. PRISMA VLC DYCAL represents the first dental use of biocompatible resin in direct contact with vital tissue.

Biocompatible Materials↗

PubMed2006

Biocompatability of hydroxyapatite composite as a local drug delivery system.

PURPOSE: To investigate the biocompatibility of hydroxyapatite composite (hydroxyapatite, plaster of Paris, and chitosan) impregnated with gentamicin, fosfomycin, imipenem, or amphotericin B. METHODS: The interactions of the extract from each drug against osteoblast were tested using the methylthiotetrazole test. RESULTS: Extracts from all drugs showed good biocompatibility at concentrations varying from 10 microgram/ml to 1000 microgram/ml. Imipenem and amphotericin B at a concentration of 1000 microgram/ml had a significantly higher percentage of cell viability than the control group. No morphological change of osteoblast was observed in all drug tests at any concentrations. CONCLUSION: The hydroxyapatite composite had a good biocompatibility for carrying gentamicin, fosfomycin, imipenem, or amphotericin B.

Amphotericin B↗