SEARCH · PubMed Health

Results for “Biocompatibility”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 703 records · Page 39Linked to original sources

PubMed2000

Biocompatibility of two current adhesive resins.

The purpose of the study was to evaluate the biocompatibility of two current adhesive resins and a calcium hydroxide cement. Fifty-four polyethylene tubes were filled with these dental materials, which were hand-mixed or light-cured according to the manufacturer's directions: group 1--Clearfill Liner Bond 2 (Kuraray); group 2--Single Bond (3 M); and group 3--calcium hydroxide cement (Dycal-Dentsply). The materials were implanted into dorsal connective tissue of rats, which were killed 7, 30, and 60 days after the implantation procedure. The implant sites were excised, immersed in buffered Karnovsky's fixative, and processed using routine histological techniques. Sections of 6 microns thickness were stained with hematoxylin and eosin and assessed under light microscopy. Both adhesive resins at 7 days elicited a moderate/intense inflammatory reaction that decreased over time. Fibrous capsules surrounding the tubes were observed at 30 days. Half of the samples in groups 1 and 2 showed thin fibrous capsule formation containing macrophages, capillaries, lymphocytes, fibroblasts, and collagen fibers. Connective tissue healing was observed even though many specimens exhibited a persistent inflammatory reaction mediated by macrophages and giant cells at the 60-day evaluation. Dycal allowed complete healing at 30 days with only a thin fibrous capsule. In conclusion, all experimental materials were successfully walled off by the connective tissue of the rat. However the adhesive resins may release particulates that may, in turn, induce a persistent local inflammatory reaction. Consequently, in this specific condition, these materials cannot be regarded as biocompatible. Dycal was less irritating than the adhesive resins and was better tolerated by the connective tissue.

Animals↗

PubMed1996

Titanium aneurysm clips: Part I--Mechanical, radiological, and biocompatibility testing.

Most aneurysm clips are made of cobalt-based alloys. Although these clips are nonferromagnetic, they still produce artifact that degrades the quality of magnetic resonance (MR) images. A new aneurysm clip of pure titanium was developed to minimize artifact on postoperative MR images. We evaluated these clips in a series of mechanical tests in vitro, biocompatibility tests in rabbits, and radiological tests in greyhound dogs. The clip sizes and shapes matched those of conventional aneurysm clips. The average closing forces ranged between 151.6 and 181.8 g and were not diminished by repeated sterilization or stress. After > 20 million cycles of high-pressure and high-frequency pulsations, the clips did not open and the closing forces were not reduced. Titanium aneurysm clips implanted in the subarachnoid space of 12 rabbits for 1 or 6 months produced mild gliosis identical to that produced by implantation of cobalt alloy clips in 12 control rabbits. Based on pre- and postoperative weights and electron microscopic scans, the titanium implants did not corrode. The artifact on computed tomographic and MR imaging produced by a titanium clip placed on the internal carotid artery of a greyhound was less than that produced by an identical cobalt-chrome alloy clip by a factor of two to three. This study demonstrated that titanium aneurysm clips are mechanically equivalent to conventional clips, biocompatible, and corrosion resistant. Furthermore, titanium clips have superior imaging characteristics, creating less computed tomographic and MR imaging artifact and permitting better resolution of anatomic structures than cobalt alloy clips.

Animals↗

PubMed2005

Biocompatibility of nitinol and stainless steel in the bladder: an experimental study.

PURPOSE: We tested the biocompatibility of nitinol, a nickel titanium alloy, and stainless steel (SS) as bladder implant materials. MATERIALS AND METHODS: Rats received a nitinol implant, an SS implant or were sham controls. Two, 3, 6 and 8 weeks following implantation 24-hour voiding behavior studies were performed to investigate bladder irritation. All animals were sacrificed 8 weeks after implantation and a sample of urine was aspirated for culture. The bladders were examined by light microscopy and scanning electron microscopy (SEM). RESULTS: No visible encrustations or infections were noted in urine. Voiding frequency in the light period 6 weeks after implantation was significantly decreased in the 2 implant groups compared with sham controls. There were no other significant differences in frequency or mean volume per void in the light or dark periods at any time point. Light microscopy demonstrated similar implant tissue effects in all groups with little or no inflammation or fibrosis. Under SEM all implants showed a brittle, amorphous coating devoid of cells. The transition between the urothelium mucosa and the rod was smoother for SS than for nitinol, suggesting an affinity of SS for mucosa. In all nitinol rods discontinuity was present between the mucosa and rod. CONCLUSIONS: Nitinol and SS do not cause more irritation than the effects of surgery alone and the 2 materials seem to be biocompatible in the bladder. Nitinol may be more inert than SS based on SEM results.

Alloys↗

PubMed2006

Clinical efficacy and biocompatibility of three different leukocyte and fat removal filters during cardiac surgery.

Activated leukocytes and fat particles are associated with organ injury after a cardiac surgery. Filters are currently used to remove either leukocytes or fat particles. A novel approach with a filter that combines leukocyte and fat removal might be clinically useful. As it is not known which type of filter has a good and safe performance in both leukocyte and fat removal, we measured in this study the leukocyte and fat removal properties and the biocompatibility of three different filters. We used six Pall RS1 (Pall, Portsmouth, England) leukocyte removal filters, six Pall LipiGuard fat removal filters, and six Fresenius Biofil 02 (Fresenius, Emmer-Compascuum, The Netherlands) leukocyte removal filters and measured the passage times of 500 and 1000 mL of residual heart-lung machine blood. We determined the circulating leukocyte and platelet counts, and total hemoglobin, triglyceride, and free fatty acid concentration after the filters. In addition, we measured free hemoglobin, plasma elastase (Merck, Darmstadt, Germany), and complement C5-9 (Quidel, San Diego, CA, U.S.A.) to assess the biocompatibility of the filters. The circulating fat particles were calculated with an automated hematology analyzer. The passage time for the blood was shortest for the Biofil filter (P = 0.02, analysis of variance). The total leukocyte counts (P = 0.04) and fat particles (P = 0.02) were higher after the LipiGuard filter. This filter also had a higher increase in free hemoglobin concentration (P = 0.03). We conclude that the leukocyte removal filters were superior to the fat removal filter both in leukocyte and fat removal.

Aged↗

PubMed1981

Stimulation of the spinal neuraxis by biocompatible electrical current in the human.

A 5-year retrospective study shows that stimulation of the neuraxis by biocompatible on-demand electrical energy systems is an effective alternative in the management of chronic organic regional pain syndromes. The clinical criteria of improved sense of well-being - reduction of drug intake and increase in activities of daily living - were employed to show that 50% of selected patients reported improvement in 60% of the cases in which stimulation-induced hypalgesia (SIH) was present. There is no apparent significant difference between mono- and bipolar electrical systems. There was no surgical mortality in the series. Complications of electrode migration (6%), rejection syndrome (14%), infection (6%) and unknown causes (8%) did present technical problems that are being resolved. Granulation tissue, apparently stimulated by electrical energy, suggests application in the healing processes. The existence of a variable response neuronal adaptation system is suggested in some patients by the drop in stimulation efficacy after long-term stimulation of fully implanted systems. Challenge of SIH by antagonist naloxone produced variable responses in cooperative patients. The soporific effect seen with transcutaneous electrical nerve stimulation reported in 40% of cases is not seen with the fully implanted epidural systems, despite the use of similar on-demand pulse generators. Biocompatible electrical stimulation of the spinal neuroaxis holds promise as a management modality for highly selected human patients with chronic pain syndromes.

Adult↗

PubMed2003

Comprehensive biocompatibility testing of a new PMMA-hA bone cement versus conventional PMMA cement in vitro.

For more than 50 years PMMA bone cements have been used in orthopaedic surgery. In this study attempts were made to show whether cultured human bone marrow cells (HBMC) show an osteogenetic response resulting in new bone formation, production of extracellular matrix (ECM) and cell differentiation when they were cultured onto polymerized polymethylmethacrylate (PMMA)-hydroxyapatite (HA), conventional PMMA bone cement being taken as reference. Biocompatibility parameters were collagen-I and -II synthesis, the detection of the osteoblast markers alkaline phosphatase (ALP) and osteocalcin, the number of adherent cells and the cytodifferentiation of immunocompetent cells. Cement surface structure, HA stability in culture medium and chemical element analysis of specimens were considered. Fresh marrow cells were obtained from the human femora during hip replacement. Incubation time was up to ten weeks. We used atomic forced microscopy (AFM) and scanning electron microscopy (SEM) for cement specimen analysis. Fluorescent activated cell sorter (FACS), immunohistochemical staining. SEM and light microscopy (LM) served us to judge the cellular morphology. Products of the extracellular matrix were analyzed by protein dot blot analysis, SEM energy dispersive X-ray analysis (SEM-EDX) and Ca2+/PO(4)3- detection. HA particles increased the osteogenetic potential of PMMA bone cement regarding the cellular production of collagen, alkaline phosphatase (AP), the number of osteoblasts and the cellular differentiation pattern in vitro. Both tested cements showed good biocompatibility in a human long-term bone marrow cell-culture system.

Bone Cements↗

PubMed2004

A biocompatible magnetic film: synthesis and characterization.

BACKGROUND: Biotechnology applications of magnetic gels include biosensors, targeted drug delivery, artificial muscles and magnetic buckles. These gels are produced by incorporating magnetic materials in the polymer composites. METHODS: A biocompatible magnetic gel film has been synthesized using polyvinyl alcohol. The magnetic gel was dried to generate a biocompatible magnetic film. Nanosized iron oxide particles (gamma-Fe2O3, ~7 nm) have been used to produce the magnetic gel. RESULTS: The surface morphology and magnetic properties of the gel films were studied. The iron oxide particles are superparamagnetic and the gel film also showed superparamagnetic behavior. CONCLUSION: Magnetic gel made out of crosslinked magnetic nanoparticles in the polymer network was found to be stable and possess the magnetic properties of the nanoparticles.

Journal Article↗

PubMed1998

[Characterization of the properties of differentially modified titanium surfaces for dental implantology. 2: In vitro biocompatibility studies].

The aim of the present study was to determine whether specific surface modifications are capable of improving the biocompatibility of a titanium surface, and whether there is a correlation between the physico-chemical properties of the implant material and its biocompatibility. To this end, the properties of titanium surfaces were modified using various methods or the latter were coated with various materials. Plasma treatments under different atmospheric conditions (N2-plasma, SO2-plasma, acetylene plasma) as well as plasma polymerization were used to affect the biological response. Characterization of the physico-chemical surface properties by means of X-ray photoelectron spectroscopy (XPS), contact angle measurements and the calculation of surface tensions or surface energy provided important information on the interactions at the interface between the implant material and the aqueous environment. The influence of the respective surface modification on cell proliferation, cell viability and the activity of mitochondrial dehydrogenases was evaluated in specific in vitro tests with human gingiva fibroblasts. It was show that different modifications of the titanium samples induce different biological responses of the gingiva fibroblasts. The results confirm the existence of correlations between thermodynamic surface properties and cellular reactions under in vitro conditions.

Cell Division↗

PubMed2005

[Comparative study of the biocompatibility of the porcine intestinal submucosa and bovine pericardium used as grafts in the inferior cava vein of dogs].

PURPOSE: To compare the biocompatibility of the bovine pericardium and the small intestine submucosa (SIS) when used to repair a created defect in the inferior vena cava of dogs. METHODS: Sixteen male mongrel dogs were submitted to a midline laparotomy incision. An elliptical segment (1.5 x 3.0 cm) of the inferior vena cava, below the renal veins, was excised. In 8 dogs, the A group, a patch of porcine small bowel submucosa was used to repair the defect. In the 8 remaining dogs, the B group, a bovine pericardium was implanted in the vena cava. On the 30th post-operative day an ultrasound was performed in order to identify stenosis. The euthanasia was accomplished in the 40th post-operative day. Stenosis of the vein was observed in 1 dog of A group and in 2 of the B group. RESULTS: Partial thrombosis with collateral circulation was evidenced in 1 dog of the bovine pericardium group. A moderated chronic inflammatory process was evidenced in both groups. Microscopic evaluation, regarding endothelization of the implant, collagen deposition, smooth muscle growth, was similar in both groups. CONCLUSION: SIS proved to be a functional graft patch for possessing local vena cava remodeling and its biocompatibility was similar to bovine pericardium.

Animals↗

PubMed2001

Analysis of brain biocompatibility of drug-releasing biodegradable microspheres by scanning and transmission electron microscopy.

OBJECT: Stereotactically guided implantation of biodegradable microspheres is a promising strategy for delivery of neurotrophic factors in a precise and spatially defined brain area. The goal in this study was to show the biocompatibility of poly(D,L,lactide-co-glycolide) microspheres with brain tissue at the ultrastructural level and to analyze the three-dimensional (3D) ultrastructure after intrastriatal implantation of these microparticles. METHODS: Scanning and transmission electron microscopy were used to study the microspheres and their environment after implantation in an inert material (gelatin) and in the rat striatum. Observations were made at different time periods, ranging from 24 hours to 2 months postimplantation. CONCLUSIONS: The progressive degradation of the microspheres, with vacuolization, deformation, and shrinkage, was well visualized. This degradation was identical in microspheres implanted in the inert material and in the rat brain tissue, independent of the presence of macrophages. The studies preformed in the striatum permitted the authors to demonstrate the structural integrity of axons in contact with microspheres, confirming the biocompatibility of the polymer. Furthermore, scanning electron microscopy showed the preservation of the 3D ultrastructure of the striatum around the microparticles. These microparticles, which can be stereotactically implanted in functional areas of the brain and can release neurotrophic factors, could represent, for some indications, an alternative to gene therapy.

Animals↗

PubMed2005

Biocompatibility parameters in in-vitro simulated automated versus continuous ambulatory peritoneal dialysis.

BACKGROUND: In peritoneal dialysis, the usage of automated peritoneal dialysis (APD) has been steadily increased. As APD means larger volumes of solution and more frequent contact times with fresh dialysate, an additive negative impact on biocompatibility data, exceeding the known effect of conventional PD fluids, seems possible. For an in-vitro comparison of APD and CAPD, a new cell culture system has recently been established. METHODS: A double chamber cell culture system with human mesothelial cells on top of a permeable membrane and growth medium beyond was used for mimicking CAPD and APD. Reflecting the in vivo equilibration pattern, we compared an eight-hour CAPD with a CCPD setting, using a conventional PD solution. Cell viability was assessed with a MTT assay and cell function via constitutive and stimulated IL-6 release. CA125 was measured as a parameter of mesothelial cell integrity, and TGF-1beta was measured as an index of induction of fibrosis. RESULTS: Both the CAPD and the CCPD mode resulted in a significantly lower MTT assay and stimulated IL-6 release compared to growth medium. TGF-1beta and CA125 release did not differ between the PD modes and control. The CAPD and the CCPD mode itself did not differ with regard to MTT assay, IL-6 release, TGF-1beta and CA125 generation. CONCLUSION: From the in-vitro model imitating the acute exposure of mesothelial cells with conventional PD fluid in a CCPD and CAPD mode, there is no evidence that APD, due to the larger volumes of solution and more frequent contact times with fresh dialysate, has an acute, additive negative impact on biocompatibility parameters indicative for peritoneal host defense, mesothelial cell integrity and peritoneal fibrosis.

CA-125 Antigen↗

PubMed2000

Biocompatibility of new peritoneal dialysis solutions: clinical experience.

The successful development of peritoneal dialysis (PD) during the last two decades has been made possible by using well-established glucose-based solutions with lactate as buffer. On the other hand, awareness has been increasing about the potentially negative effects of the high concentrations of glucose and lactate, and the low pH of conventional PD solutions. This awareness has prompted an intensive effort to search for and test alternative solutions. As a result, three new, more biocompatible solutions-containing either less glucose or less lactate--are available. Amino acid-based solution uses amino acids instead of glucose as the osmotic agent; it is indicated for treatment of malnutrition. The higher pH and absence of glucose in this solution may prevent alterations of the peritoneal membrane caused by acidity and high glucose concentrations. Bicarbonate/lactate-buffered solution contains a physiologic concentration of bicarbonate and a reduced concentration of lactate; it also has a physiologic pH and markedly reduced levels of glucose degradation products (GDPs). Icodextrin-based solution contains icodextrin as the osmotic agent; it is indicated for long dwells, delivering sustained ultrafiltration for more than 16 hours. This iso-osmolar glucose-free solution may reduce peritoneal membrane alterations caused by glucose or the hyperosmolality (or both) of conventional solutions. Clinical experience of the new solutions is now extensive, and their efficacy and safety are well documented. It therefore seems appropriate to state that we have entered a new era of PD therapy. Each of the new solutions may be less damaging to the peritoneal membrane than conventional solution. In addition, they permit better management of malnutrition and fluid status, and may thus help to improve PD patient survival. Although the effects of each of these new solutions have been well described, clinical documentation of the combined use of these new biocompatible PD solutions is still insufficient. However, the results of studies are expected, during the coming years, to support the combined use of the new solutions as the preferred standard practice for PD.

Amino Acids↗

PubMed1999

[Biocompatibility of self-designed absorbable hydroxyapatite/poly (DL-lactide) composites].

The biocompatibility of self-designed hydroxyapatite/poly (DL-lactide) rods was evaluated both in vitro and in vivo including Ames test, micronucleus test, acute and subacute systemic toxicity test, hemolysis test, hemopexis test and long-term muscle and bone implant test. The results indicate that the material has no toxicity, no stimulation and mutation, and it does not cause hemolysis and hemopexis. Consequently, the biocompatibility of the composite was good.

Absorbable Implants↗

PubMedDate not supplied

In vivo evaluation of the biocompatibility of the totally implantable ventricular assist device (HeartSaver VAD).

A series of multicenter in vivo studies have been conducted to assess the biocompatibility and device performance of the HeartSaver VAD, a totally implantable pulsatile ventricular assist device (VAD). The experiments (n = 23) were conducted in calves with a mean weight of 101 (75-152) kg. Implants took place at four centers using two different surgical procedures of implantation (one with cardiopulmonary bypass and one without). Three anticoagulation regimens were used (one with continuous intravenous heparin, one with oral warfarin, and one with oral warfarin combined with antiplatelet clopidogrel therapy). Device function and biochemistry were monitored during the study, and organs and device analysis were conducted at explant. There were six nonsurvivors because of early surgical complications (during the first week of support). The postoperative courses in the remaining 17 (74%) calves were uneventful. Hemodynamic and biocompatibility indicators were monitored throughout the study. The mean duration of device support for those cases was 48 (13-92) days. Mean device flow was 7.15 (+/- 1.68) L/min. There were no deaths caused by infection; however, two animals developed endocarditis believed to be caused by the percutaneous instrumentation lines used for the study. No severe bleeding requiring reoperation occurred during the study. The mean plasma free hemoglobin was within normal limits at 6.8 +/- 2.6 mg/dl. Renal and hepatic functions were normal with a mean creatinine of 0.6 +/- 0.1 mg/dl and a mean aspartate aminotransferase of 68.7 +/- 42.6 mg/dl. Several device related improvements were identified and have now been implemented. Additional bovine implants with an optimized device are currently underway in preparation for human trials.

Animals↗

PubMed2003

[Experimental study of biocompatibility of LIFEs in peripheral fascicles].

OBJECTIVE: To study the biocompatibility of longitudinally implanted intrafascicular electrodes (LIFEs) in a rabbit sciatic nerve model. And to discuss the possibility of peripheral fascicular signals as a new signal source to control an electronic prosthetic hand. METHODS: LIFEs were implanted chronically into sciatic peripheral fascicles of rabbits as recording and stimulating electrodes. Motor-evoked potentials (MEP) and cortical somatosensory-evoked potentials (CSEP) were recorded by using a transcranial stimulation system (TCS) over six-month period to observe the change of the signals recorded. At the end of the experiments, the fascicles at the electrodes implanted site were anatomized for histological examination under light microscope and transmission electron microscope. In human test, LIFEs were implanted into radial nerve, ulnar nerve and medial nerve of an amputee volunteer. Signals were detected when the volunteer was asked to do different movements of his missing hand, and the signals recorded by LIFEs were used to control an electronic prosthetic hand. RESULTS: The difference of onset latency (OL) of MEP and CSEP recorded at different time has remarkable statistical significance (one way ANOVA, P < 0.001). After multiple comparisons, onset latency (OL) of MEP and CSEP had no obvious change during 1 month, but significantly increased in the later time, and then became stable after 3 months after implantation. The difference of the interpeak amplitudes (IPAs) of MEP recorded at different time has remarkable statistical significance (one way ANOVA, P < 0.001). The interpeak amplitudes (IPAs) of MEP had no distinct change during 1 month, but significantly decreased over the next period, and then became stable after 3 months. Though the interpeak amplitudes (IPAs) of CSEP decreased slowly over six-month period of the study, the difference has no statistic significance (one way ANOVA, P > 0.05). At the end of experiment, histological examination indicated that a typical foreign body reaction developed and electrodes caused a mild damage to fascicles. But inflammatory cells and neuroma were not seen around the electrodes. Signals recorded by LIFEs planted in proximal radial, ulnar and median nerve of the amputated arm were different when the amputee volunteer was ordered to do some different movements with his mind. Some signals could be used to control the seven-freedom electronic prosthetic hand. CONCLUSIONS: Longitudinally implanted intrafascicular electrodes (LIFEs) have excellent biocompatibility with peripheral fascicles. They can be implanted chronically into fascicles and record signals. Furthermore, LIFEs can record physiological signals of peripheral fasciculi when hand moves, and these signals could be used to control an electronic prosthetic hand through further research.

Adult↗

PubMedDate not supplied

[In vivo and in vitro biocompatibility tests of endodontic cements].

The major goal endodontic therapy has been achieved by condensing filling materials into the root canal. It's not uncommon to find excess material into the periapical tissue. It therefore becomes obligatory to use fillings materials that have acceptable biocompatibility. The purpose of this investigation was to obtain a "toxicity profile" of some endodontics materials and to compare our observations to results present in literature. The gutta-percha and five endodontic filling cements were tested "in vivo" and "in vitro". The in vivo biocompatibility involved the placement of the test material in 10 mm. Teflon tubes with an outer diameter of 1.3 mm which were implanted subcutaneously into rats. The implants were left in situ for periods of 30 and 90 days. The "hemolysis test" is designed for "in vitro" evaluations. The histological examination showed different intensity and extent cellular responses. In some cases severe infiltration of inflammatory cell and areas with necrotic were seen. At conclusion, the endodontics material evaluated showed slight, moderate and severe reactions; therefore a different pattern in tissue response.

Animals↗

PubMed2001

[Histological evaluation of the biocompatibility of PDLLA membranes].

OBJECTIVE: To evaluate the histological response and biocompatibility of implanted domestic bio-degradable PDLLA membranes in vivo. METHODS: The domestic biodegradable PDLLA membranes and non-degradable ePTFE membranes were in pairs placed subcutaneously in surgical incision made in the dorsum of rats. The tissue responses to these materials were observed histologically at 1, 2, 4, 8 and 12 weeks after placement. RESULTS: The tissue responses of the two kinds of materials were similar to the non-specific reaction mainly infiltrated with lymphocytes, plasmocytes, macrophages, and foreign body giant cells. The polymorphonuclears and foreign body giant cells infiltrated round the ePTFE membranes existed for a relatively long period, in contrast to that of PDLLA membranes. CONCLUSION: Domestic PDLLA membranes with good biocompatibility will be adapted to making GTR into a single step procedure.

English Abstract↗

PubMedDate not supplied

[Biocompatibility of the acetate in the dialysis fluid].

PURPOSE: Dialytic vasculopathy is a major morbidity and mortality risk factor in patients undergoing chronic dialysis treatment. Among the pathogenetic factors some are related to the uremic condition, others are due to biocompatible reactions to dialytic materials. Endothelial cells (EC) are the target of the mediators released during bioincompatible reactions, and the related effects could be considered the initial event eliciting the vasculopathy pathogenesis. Among the others, we focused our attention on the role played in this process by the inducible isoform of nitric oxide (NO) synthase (iNOS). In previous studies we demonstrated that bioincompatible membranes, as well as acetate-containing dialysis buffers stimulate iNOS gene expression and activity in endothelial cells in culture. In this study, we planned to evaluate the potential role of a new dialysis buffer in which acetate has been substituted with HCl as a stabilizer. METHODS: ECs were incubated for 12 h at 37 degrees C with different dialysis buffers: acetate (Acet), standard bicarbonate (Bic), acetate-free buffer (AF) and HCl-bicarbonate (BicHCl). We evaluated in reverse transcriptase polymerase chain reaction (RT-PCR) the gene transcription for iNOS, the NOS activity (as the production of H3 citrulline from H3 arginine by ionic exchange chromatography), EC proliferative (H3 thymidine incorporation) and pro-apoptotic rate (TUNEL analysis) and the nuclear translocation of the transcriptional factor NF-kappaB (EMSA). RESULTS: Acetate, even in the low concentration present in Bic was able to induce a significant iNOS gene transcription (results expressed as relative units and referred to basal values: Acet 1.9 +/- 0.01 fold increase, p<0.01; Bic 1.45 +/- 0.03 p<0.05; BicHCl 1.24 +/- 0.01; AF 1.17 +/- 0.02) and translation. Acetate at concentrations both of 3 mmoL and 38 mmoL (present in the bicarbonate buffer) significantly increased the enzymatic NOS activity vs unconditioned ECs: Acet 3.46 +/- 0.3, p<0.0005; Bic 1.69 +/- 0.2, p<0.005; BicHCl 1.24 +/- 0.15; AF 1.17 +/- 0.05. The EC proliferative index was significantly depressed by acetate containing dialysis buffers (unconditioned ECs 100%, Acet 38 +/- 15%, p<0.01; Bic 65 +/- 6%, p<0.05; AF 87 +/- 8%; BicHCl 75 +/- 6%). The percentage of apoptotic ECs was significantly increased by buffers contain-ing Acet vs BicHCl and AF. Finally, acetate at the concentrations present in Acet and Bic activated and promoted the nuclear translocation of the transcriptional factor NF-kappaB in ECs (p<0.01 vs unconditioned cells). CONCLUSIONS: The acetate-free dialysis buffers have better biocompatibility and potentially down-modulate the flogistic and sclerotic processes responsible for dialytic vasculopathy.

Acetates↗