Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new polymeric biomaterial, which uniquely combines radio-opacity (X-ray visibility) and low thrombogenicity, is described. First, preparation, purification, and identification of the essential monomeric building block, 2-[2'-iodobenzoyl]-ethyl methacrylate (3), are outlined. Second, [Figure: See text] the synthesis of the biomaterial, a terpolymer with composition MMA: HEMA: 3 = 65:15:20 (mole/mole/mole) is described. Third, the physico-chemical characteristics of the polymer (e.g. NMR spectroscopy, thermal behaviour) are given. Fourth, the in vitro thrombogenicity of the material was characterized by means of recent test assay. The combined results reveal that the terpolymer is very suitable for prosthetic applications in the cardiovascular system. A new prototype of an endovascular stent, made from the terpolymer, is presented. Stents find clinical use in interventional cardiology, in conjunction with percutaneous transluminal coronary angioplasty (PTCA). It is put forward that the stent prototype presented herein has, at least in principle, some advantages over existing (metallic) stents; these advantages are primarily owing to the unique combination of X-ray visibility and haemocompatibility which is presently achieved.
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PMID:Studies on radio-opaque polymeric biomaterials with potential applications to endovascular prostheses. 887 20

The diffusion of water into a series of hydroxyethyl methacrylate, HEMA, copolymers with tetrahydrofurfuryl methacrylate, THFMA, has been studied over a range of copolymer compositions using NMR imaging analyses. For polyHEMA the diffusion was found to be consistent with a Fickian model. The mass diffusion coefficient of water in polyHEMA at 37 degrees C was determined from the profiles of the diffusion front to be 1.5 x 10(-11) m(2) s(-1), which is less than the value based upon mass uptake, 2.0 x 10(-11) m(2) s(-1). The profiles of the water diffusion front obtained from the NMR images showed that stress was induced at the interface between the rubbery and glassy regions which led to formation of small cracks in this region of the glassy matrix of polyHEMA and its copolymers with mole fractions of HEMA greater than 0.6. Water was shown to be able to enter these cracks forming water "pools". For copolymers of HEMA and THFMA with mole fractions of HEMA less than 0.6 the absence of cracks was attributed to the ability of the THFMA sequences to undergo stress relaxation by creep.
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PMID:NMR imaging of water sorption into poly(hydroxyethyl methacrylate-co-tetrahydrofurfuryl methacrylate). 1174 13

Magnetic resonance imaging has been used to monitor the diffusion of water at 310 K into a series of semi-IPNs of poly(ethyl methacrylate), PEM, and copolymers of 2-hydroxyethyl methacrylate, HEMA, and tetrahydrofurfuryl methacrylate, THFMA. The diffusion was found to be well described by a Fickian kinetic model in the early stages of the water sorption process, and the diffusion coefficients were found to be slightly smaller than those for the copolymers of HEMA and THFMA, P(HEMA-co-THFMA), containing the same mole fraction of HEMA in the matrix. A second stage sorption process was identified in the later stage of water sorption by the PEM/PTHFMA semi-IPN and for the systems containing a P(HEMA-co-THFMA) component with a mole fraction HEMA of 0.6 or less. This was characterized by the presence of water near the surface of the cylinders with a longer NMR T(2) relaxation time, which would be characteristic of mobile water, such as water present in large pores or surface fissures. The presence of the drug chlorhexidine in the polymer matrixes at a concentration of 5.625 wt % was found not to modify the properties significantly, but the diffusion coefficients for the water sorption were systematically smaller when the drug was present.
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PMID:NMR imaging of the diffusion of water at 310 K into semi-IPNs of PEM and poly(HEMA-co-THFMA) with and without chlorhexidine diacetate. 1524 58

The strategy of phospholipid-based biomimicry has been used to molecularly engineer poly(2-hydroxyethyl methacrylate) [p(HEMA)]-based hydrogels for improved in vitro and potential in vivo biocompatibility. Two methacrylate-based monomers, poly(ethylene glycol) (200) monomethacrylate (PEGMA) and 2-methacryloyloxyethyl phosphorylcholine (MPC), were incorporated at varying mole fractions of 0.0-0.5 mol% PEGMA and 0-10 mol% MPC respectively, into 3 mol% tetraethyleneglycol diacrylate (TEGDA) cross-linked p(HEMA) networks. Upon hydration of these engineered hydrogels, a reduction in receding contact angle from 22+/-1.2 degrees for p(HEMA) to 8+/-2.7 degrees for p(HEMA) containing 0.5:10 mol% PEGMA:MPC was observed, reflecting the significant increase in surface hydrophilicity with increasing PEGMA and MPC content upon prolonged hydration. Hydrogels containing MPC showed a temporal increase in hydrophilicity following continuous immersion in DI water over 5 days. Hydrogels containing 0.5 mol% PEGMA and MPC in the range of 5-10 mol% displayed reduced protein adsorption when incubated with the common extracellular matrix proteins; fibronectin, collagen or laminin, producing up to 64% less protein adsorption compared to p(HEMA). Compositional optima for cell viability and proliferation established from two-factor Central Composite design analysis of human muscle fibroblasts cultured on these hydrogels suggest that those containing PEGMA between 0.3 and 0.5 mol% and MPC levels around 5-10 mol% exhibit desirable characteristics for implant material coatings-high viability (>80%) with low proliferation (<40%), confirming a lack of cytotoxicity.
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PMID:Molecularly engineered p(HEMA)-based hydrogels for implant biochip biocompatibility. 1576 56

The biocompatibility of biosmart polymer membranes synthesized from cross-linkable (2-hydroxyethyl methacrylate) (HEMA) and tetraethylene glycol diacrylate and containing different mole-percent polyethylene glycol methacrylate (PEGMA) and methacryloyloxyethyl phosphorylcholine (MPC), a phosphorylcholine-containing co-monomer, was investigated. The cytotoxicity (cell viability and proliferation) and the adhesion of extra cellular matrix proteins to these hydrogel surfaces were separately tested. Cell proliferation assays were conducted by cultivating human skeletal muscle fibroblasts onto the surfaces of these polymeric membranes prepared by in-situ polymerization in chemically derivatized 8-well cell-culture plates. The compositions containing MPC and PEGMA concentrations greater than 1.0 and 0.05 mole% respectively demonstrated good protein adhesion and cell viability (>90%) of human muscle fibroblast cells. Morphological deviances and partial colonization of the hydrogel surface has been noticed and suggests good compatibility of hydrogels for cellular viability but restricted proliferation. It is well known that the adsorption of proteins onto biomaterial surfaces modulates the cellular interaction with these surfaces. The extent of adsorption of fluorescein labeled proteins (laminin, collagen, and fibronectin) onto these polymer membrane surfaces was evaluated by measuring the resultant fluorescence intensity using a confocal fluorescence scanner.
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PMID:Molecularly engineered hydrogels for implant biocompatibility. 1727 48

Penetration and conversion of adhesives into the hybrid layer (HL) is important to the quality and longevity of the adhesive resin (AR)-dentin bond. In this study, a methodology is developed to examine the degree of conversion and relative HEMA concentration with respect to Bis-GMA using Raman spectroscopy. This methodology will be used in the future reports related to this topic. Conversion in the AR of water-stored resin-dentin samples (84% +/- 3%) agreed well with that measured in commercial adhesive (Comm Adh) resin samples after 24-h water storage (80% +/- 2% from Part 1) and was significantly higher than Comm Adh without water storage (58% +/- 3% from Part 1) (p = 0.0005). Adhesive conversion was not significantly different (p = 0.5036) through the middle of the HL, with a mean of 83% +/- 6%. HEMA mole fraction, relative to Bis-GMA, was significantly higher (p = 0.0028) in the top half of the HL (0.67 +/- 0.03), when compared to HEMA in the AR (0.60 +/- 0.01). HEMA and EDMAB were identified through GC/MS as leachable components in the aqueous 24-h storage media. The effect of this elution explains the change in conversion measurements observed between dry and water-stored conditions, which is more appropriately described as the "apparent" conversion.
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PMID:Apparent conversion of adhesive resin in the hybrid layer, Part II: In situ studies of the resin-dentin bond. 1843 62

Patho-physiologies related to skin are diverse in nature such as burns, skin ulcers, atopic dermatitis, psoriasis etc. which impose severe bio-medical problems and thus enforce requirement of new and healthy skin prepared through tissues engineering methodologies. However, fully functional and biodegradable matrix for attachment, growth, proliferation and differentiation of the relevant cells is not available. In the present study, we introduce a set of hydrogels synthesized by incorporation of a synthetic monomer (Hydroxyethlmethacryate) with a semi-synthetic polymer backbone (carboxy methyl tamarind, CMT) in different mole ratios. We termed these materials as CMT:HEMA based hydrogels and these were characterized by different physico-chemical techniques, namely by X-Ray Diffraction, SEM and Dynamic Light Scattering. Biocompatibility studies with HaCaT, NIH-3T3 and mouse dermal fibroblasts confirm that this material is biocompatible. MTT assay further confirmed that this material does not have any cytotoxic effects. Assays for mitochondrial functionality such as ATP assay and mitochondrial reactive oxygen (ROS) generation also suggest that this material is safe and does not have any cytotoxicity. Hemolytic assay with red blood cells and acute skin irritation test on SD Rats confirmed that this material is suitable for ex-vivo application in future. We suggest that this hydrogel is suitable for in-vivo applications and may have clinical and commercial importance against skin disorders.
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PMID:Hydroxyethyl methacrylate grafted carboxy methyl tamarind (CMT-g-HEMA) polysaccharide based matrix as a suitable scaffold for skin tissue engineering. 2958 Apr 30

Measurement of modified biologic including coagulation factors with extended half-life obtained, for example, by polysialylation pose an analytical challenge especially if both biological activity and presence of modification have to be determined. Analytical methods applied so far address only 1 of the 2 quality attributes of modified biologics. Here, we describe the development and bioanalytical validation of a polysialic acid-mediated factor VIII activity assay: Polysialic acid-specific capture of polysialylated recombinant factor VIII is combined with a chromogenic FVIII activity test using commercially available reagents. This assay principle enabled measurement of FVIII activity down to the pico mole-range without any interference by nonmodified factor VIII. To the best of our knowledge, this is the first method to selectively, accurately, and precisely measure simultaneously activity and modification integrity of a polysialylated biologic in complex matrices, as shown by the bioanalytical validation data. The convenience, robustness, and reliability of using this method has been demonstrated by its application for the nonclinical development of the polysialylated recombinant FVIII preparation. The method principle could be applied to protein modifications other than polysialylation and to activity tests other than the chromogenic FVIII assay.
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PMID:Polysialic Acid-Mediated Activity Measurement of Polysialylated Recombinant Coagulation Factor VIII. 3162 21