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At least 91 records · Page 5Linked to original sources
PubMed2002

Influence of polysulfone and hemophan hemodialysis membranes on phagocytes.

The aim of the study was to compare the effect of hemophane and polysulfone membranes on the phagocyte-derived production of reactive oxygen species (ROS) as well as on neutrophil CD11b and CD62L expression in patients undergoing regular hemodialysis. The effects of hemodialysis membranes were also studied in in vitro conditions after coincubating them with differentiated HL-60 cells. ROS production was measured using chemiluminometric and flow cytometric methods. Expression of CD11b, CD62L and mitochondrial membrane potential were detected by monoclonal antibodies and by the JC-1 fluorescent probe, respectively. Depressed ROS production was observed in patients already before dialysis. Further decrease in ROS production and an increase in CD11b expression were observed especially in patients after hemophan hemodialysis. Decreased ROS production and increased CD11b expression were observed also after incubation of HL-60 cells with hemophan membranes. Mitochondrial membrane potential dropped only after incubating cells with hemophan membranes proving its more serious adverse effects in comparison with the polysulfone membrane. In conclusion, deleterious effects of hemodialysis on the metabolic activity of phagocytes were proved. Combining chemiluminescent and flow cytometric methods for the detection of ROS production and determining mitochondrial membrane potential can be useful tools for the analysis of material biocompatibility.

Aged↗
PubMed2005

[Effect of different shape and material of intraocular lens on posterior capsule opacification].

In this paper we compare 4 groups of intraocular lenses: PMMA, silicone, hydrogel, acrylic and their influence on posterior capsule opacification is discussed. The possible clinical consequences of different shape in optic part of intraocular lens is also described. This article contains also a short presentation of posterior capsule opacification mechanism and intraocular lens materials biocompatibility in in-vivo and in-vitro experiments.

Biocompatible Materials↗
PubMed2006

Will absorbable metal stent technology change our practice?

Peripheral stents aim to support revascularization procedures of intravascular stenoses by mechanically preventing vessel recoil and counteracting pathophysiologic processes of luminal re-narrowing triggered by procedural injury of the vessel wall. Despite improvements in stenting techniques and concomitant medication, repeated intervention due to target lesion re-stenosis is necessary on a significant percentage of patients. The permanent presence of an artificial implant plays a prominent role in the discussion of mechanisms causing in-stent restenosis. Permanent metallic implants pose the risk of a continuous interaction between non-absorbable stent and surrounding tissue, leading to physical irritation, long-term endothelial dysfunction, or chronic inflammatory reactions. In addition, there is a risk of stent fracture due to external mechanical forces. To overcome these shortcomings, technology of stenting has moved towards the development of temporary implants composed of biocompatible materials which mechanically support the vessel during the period of high risk for recoil and then completely degrade in the long-term perspective. This removes a potential trigger for late restenosis.

Absorbable Implants↗
PubMedDate not supplied

Coating analysis of implant materials used in orthopaedic surgery.

Biocompatibility of orthopaedic surgical implants with bone tissue allows adequate osseointegration between the bone and implant. To achieve this, implants are coated with biocompatible materials. The costly plasma spray procedure is routinely used to coat implants but uses high temperatures (over 16,000 degrees C), which affect the surface quality and microstructure of the implant. We analysed the effect of sintering temperature, time and rate on coated and uncoated implants using a dipping method. The effectiveness of synthetic hydrated calcium silicate compound as an interlayer was also investigated, using the dipping method and electrophoretic deposition. Sintering temperature, time and rate all affected the quality of the bond with the coating, but the interlayer bonded effectively with both implant and biocompatible coating. Electrophoretic deposition resulted in imperfect bonding and some irregularity on the substrate surface was seen. This technique may be improved by using coating particles of a smaller size.

Biocompatible Materials↗
PubMed1978

The biocompatibility of materials for internal fixation of fractures.

Surgically produced fractures of rabbit tibiae were internally stabilized with intramedullary rods of stainless steel (316LVM), titanium (6A1,4V), polyacetal (Delrin), and polyamide (Nylon 101). Periodic radiographs were taken until sacrifice at 16 weeks after fracture. Structural properties of the tibiae were determined in torsion with the rods in situ, and then the tissue was prepared for histology or microradiography. The results demonstrated that fracture remodeling was adversely affected by the metal rods. New bone was seen to have formed over the ends of the metal rods, and cortical bone resorption was observed in the fracture region, suggestive of transfer of mechanical stress to the rods, resulting in stress shielding of the diaphysis. Negligible osseous response to the polymeric rods was observed; fracture callus remodeling was extensive. The torsional test results demonstrated that fractures with polymeric rods were significantly stronger and tougher than those with metallic rods. With the exception of titanium, the strength of healed fractures was inversely related to the elastic moduli of the implant materials.

Acetals↗
PubMedDate not supplied

[Human bone marrow cell culture--a sensitive method for the evaluation of the biocompatibility of materials used in orthopedics].

The objective of the study was to develop a test system to determine the cytotoxicity and biocompatibility of different biomaterials used in orthopedic surgery. This system was based on the use of a human bone marrow cell culture and the purpose was to find a screening method as a alternative to early animal experimental methods. The established human bone marrow cell culture has certain advantages when compared with other cell culture models. The result demonstrated a high conformity with animal experimental results.

Biocompatible Materials↗
PubMed1993

[Biocompatibility of materials used in cardiovascular prostheses: a comparison between bovine pericardium and Dacron].

During the past 25 years, numerous studies relating to medical device biocompatibility have appeared world-wide. Development of biomaterials for grafting cardiovascular applications has contributed to an increase in knowledge of the compatibility between synthetic or biological surfaces and blood. The biocompatibility of one of the materials most commonly used in the fabrication of xenograft heart valves, bovine pericardium, treated with glutaraldehyde and formaldehyde is assessed comparison to a synthetic material, Dacron tricot. An in vitro tissue culture assay, by the agar overlay method, using RC-IAL and Hela cell lines, was applied to treated pericardium and attested the intense toxicity of the treating agents. The subcutaneous grafting of treated pericardium and Dacron was carried out in Wistar rats of 1 to 3 months of age. After the use of the usual histological methods, an evaluation of hematoxylin-eosin stained specimens demonstrated an absence of histocompatibility, mainly as regards for the formaldehyde treated pericardium. Comparatively, the evaluation of implanted Dacron confirmed it's perfect biocompatibility. In conclusion, some improvement in xenograft heart valves is necessary, before the surgical implantation procedure takes place.

Animals↗
PubMed1999

Pulpo-dentin protection: the biocompatibility of materials most commonly used in restorative work. A literature review.

The complexity and importance of the biological structures that form the so-called pulpal dentinal complex call for considerable accuracy during restorative procedures. In practice this means accurate techniques and appropriate dental materials, able to combine protective and restorative qualities, and above all, offering biocompatibility. In order to analyze this property, a number of international studies suggest the use of sequential tests divided into three different levels: initial tests, secondary tests and usage tests in the form of in vivo and in vitro tests to observe and simulate the biological reactions to dental materials used in particular tissues. The authors publish a review of the literature regarding the biocompatibility of intermediate materials regarded as useful aids in restorative dental practice; these include paints, liners and cavity bases made from Ca(OH)2, ZOE cements, zinc phosphate, polycarboxylic compounds, glass ionomers, bonding agents and mordents. The chemical, biological, clinical and utilization parameters are outlined for each compound, paying special attention to the problem of biocompatibility and indicating the pulpal reactions reported over the past decade in connection with their use. In conclusion, while waiting for a standard international document to codify evaluation methods and classify the results obtained, these experimental data can be used to programme a more correct and safer use of materials.

Biocompatible Materials↗
PubMed1996

Implantation of collagen plugs into incisional keratotomies.

PURPOSE: To evaluate whether supplementing incisional keratotomy bulk or gape with a biocompatible material enhances the refractive effect. SETTING: Refractive Surgery Laboratory, Massachusetts Eye and Ear Infirmary, Boston. METHODS: Collagen punctal plugs were implanted into astigmatic keratotomy (AK) incisions in the right eyes of five rabbits and six adult cats. The left eyes had AK only and served as controls. RESULTS: Some of the postoperative corneal topographic measurements suggested an enhanced refractive effect. At 1 month, histology demonstrated no remaining implant material and no inflammation in or near the incisions. CONCLUSIONS: Implanting a biocompatible material into AK incisions in two live animal models appears to be safe and may enhance the effect of the incisions. Further study is needed to quantify the magnitude and duration of any refractive effect.

Animals↗
PubMedDate not supplied

[Is fracture healing in the presence of biocompatible implant materials tantalum and niobium different in comparison to steel implants?].

It was our intention to investigate whether biologically inert metals like Tantal and Niob can influence fracture healing. Two series of tests - one septic and one aseptic - each with 18 rabbits were set up. An iatrogenic fracture of the tibia was intramedullary fixed with Niob-, Tantal- and steel-wire. Our aseptic cases didn't show any influence on the undisturbed secondary fracture healing. In all of our cases in which we provoced an osteitis a more intensive neoformation of bone occurred in those cases in which Tantal wire was implanted.

Alloys↗
PubMed2005

Statistical correlation between cell adhesion and proliferation on biocompatible metallic materials.

Our ambition for several years is to appreciate and quantify the long-term adhesion of cells on materials at times where the interface between cells and substrate becomes more complex, more closed to the cell/matrix/substrate interface existing in vivo. With this objective, we quantified the long-term adhesion and proliferation of human osteoblasts cultured from 24 h to 21 days on pure titanium, titanium alloy, and stainless-steel substrates presenting six different surface morphologies and two different roughness amplitude. Hence, we did proceed to the statistical correlation of cell adhesion and cell proliferation on 30 different substrates. Additionally, we described surface topography not only by the roughness amplitude but also by the roughness morphology using new specific parameters. By multiple analysis of variance, we demonstrated that nor material composition nor surface roughness amplitude did influence cell proliferation, whereas a very significant influence of the process used to produce the surface was observed meaning that the main influent factor on cell proliferation was the surface morphology. The long-term adhesion and proliferation capacity of cells were positively correlated on 23 types of substrates on 30, this positive correlation being statistically asserted on 13 types of substrates on 23. This study is the first demonstration of the existence of a statistical correlation between long-term adhesion and proliferation capacity of human bone cells on substrates with various chemical composition, surface chemistry, and surface topography.

Biocompatible Materials↗
PubMed2005

[Corrosion behaviour, metal release and biocompatibility of implant materials coated by TiO2-sol gel chemistry].

Alloys based on titanium or cobalt have been used as implant materials for decades with good success. Because of their natural oxide layer these alloys reveal good corrosion behaviour. In contact with physiological solution metal release takes place, which can cause inflammation. Coatings can improve the corrosion behaviour. In this study Ti6Al4V and Co28Cr6Mo alloys, which are frequently used as implant materials, were tested. Polished discs of these alloys and polished discs, which were coated with TiO2-layers by sol-gel chemistry, were compared regarding their corrosion behaviour and metal ion releasing. The releasing of Al, V, Ti, Co, Cr and Mo was quantified by ICP-MS analysis. The TiO2-coating reduced the release of all ions except of the Al-ion. Both alloys showed a deviating kinetic of ion releasing. In addition, cell response (cell vitality, cell proliferation, endothelial marker CD31 and actin allocation) of osteoblasts and endothelial cells were investigated.

Cells, Cultured↗
PubMed2003

Effects of mineral trioxide aggregate (MTA) extracts on mitogen-activated protein kinase activity in human osteosarcoma cell line (U2OS).

Extracellular regulated kinases (ERKs)-1 and -2 are members of the MAPK family of protein kinases involved in the proliferation, differentiation and apoptosis of bone cells. The purpose of the present study investigated the biocompatibility role, and signaling pathways of components of mineral trioxide aggregate (MTA) by culturing human osteosarcoma cell line (U2OS) in the presence of materials. Biocompatibility effects were assessed using the MTT assay for mitochondrial enzyme activity. The statistical analysis of the survival rate was performed using one-way analysis of variance (ANOVA) with p<0.05 shown statistical difference. The signaling pathway of MTA-treated U2OS cells were assessed by the western blotting methods. Dose-dependent and time-dependent tests were conducted. The results showed that the survival rates of the MTA extract experimental groups were higher than that of the control group (p<0.05). ERKs activity was dose-dependent, decreasing as the concentrations of the MTA extract decreased, and was time-dependent, decreasing as the treatment time increased. Suppression of ERK pathway by PD98059 resulted in dose-dependent and time-dependent decreases. The findings suggest that MTA is a biocompatible material to U2OS cells, and the ERK kinase pathway plays a signal transduction role in the MTA treated U2OS cells.

Aluminum Compounds↗
PubMed2005

Architecture of a biocompatible supramolecular material by supersaturation-driven fabrication of its fiber network.

The architecture of a biocompatible organogel formed by gelation of a small molecule organic gelator, N-lauroyl-L-glutamic acid di-n-butylamide, in isostearyl alcohol was investigated based on a supersaturation-driven crystallographic mismatch branching mechanism. By controlling the supersaturation of the system, the correlation length that determines the mesh size of the fiber network was finely tuned and the rheological properties of the gel were engineered. This approach is of considerable significance for many gel-based applications, such as controlled release of drugs that requires precise control of the mesh size. A direct cryo-transmission electron microscopy (TEM) imaging technique capable of preserving the network structure was used to visualize its nanostructure.

Cryoelectron Microscopy↗
PubMed1993

Biocompatibility: its future in prosthodontic research.

The future of prosthodontic research will involve replacing lost tissues by using scientific methods that evaluate biomaterials and treatment designs based on desired biologic outcomes. The present concept of a biocompatible material is one that elicits an appropriate host response in a specific application. To design optimal biomaterials, three interactive components should be considered: the chemical nature of the surface, the mediating pellicle layer, and microbial and host response. Surface chemistry determines which molecules are selectively absorbed onto a surface from oral fluids. The pellicle-coated surface should be designed to elicit a more desirable host response. Pellicle composition can be altered by chemically changing the surface, precoating surfaces with biological molecules, or using synthetic materials designed to mimic natural tissues. Several surface-sensitive techniques are available to assess these modifications, including vibrational spectroscopy, electron microscopy for chemical analysis, and bioanalytical methods. To develop more biocompatible materials, a further understanding of pellicle formation as a function of surface composition, microbial adhesion to biomaterials, and cellular reaction to implant biomaterials is necessary. This knowledge will facilitate development of new biologically based rationales for treatment modalities in restorative dentistry.

Biocompatible Materials↗