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PubMed1975

Serum protein analysis following implantation of methyl methacrylate in rats.

Thirty-six Sprague-Dawley white rats were implanted with methyl methacrylate and bone wax in a 1:1 ratio. At periods of 1, 3, 5, 7, 10 and 14 days-post-implantation arterial blood samples were drawn and the serum protein separated electrophoretically. A significant depression in the alpha 1 and alpha 2 fractions of the methacrylate animals was demonstrated as was a significant increase in the beta fraction of the 3 day group. There was a sustained depression of the alpha 1 fraction in the methacrylate animals in a 3 day and a 5 day time period. It is not felt, however, that this is indicative of a mechanism for the diverse phenomena that have been described secondary to implantation of methyl methacrylate.

Alpha-Globulins↗

PubMed2005

Surface-modified hemispherical polystyrene/polybutyl methacrylate composite particles.

Micrometer-sized polystyrene/poly(n-butyl methacrylate) composite particles of hemisphere morphology and narrow size distribution were prepared by a process of single-step swelling of uniform polystyrene template microspheres with emulsion droplets of the monomer n-butyl methacrylate containing the initiator benzoyl peroxide in the presence, or absence, of the co-swelling agent toluene. Butyl methacrylate was then polymerized at 73 degrees C within the template microspheres. Surface and bulk characterization of the particles were performed by methods such as FTIR, elemental analysis, XPS, advancing contact angle, light microscope, SEM, and cross-sectional TEM. Selective surface functionalization of the poly(n-butyl methacrylate) phase of the composite particles was performed by carrying out a similar swelling and polymerization process in the presence of a water-soluble vinylic monomer such as acrylamide.

Journal Article↗

PubMed1975

Use of combined chromatographic methods including thin-layer chromatography for analysis of complex polymer systems. Determination of the polydispersity of block copolymers of styrene and methyl methacrylate by gel permeation, thin-layer and pyrolysis gas chromatography.

A combination of gel permeation chromatography (GPC), thin-layer chromatography (TLC) and pyrolysis gas chromatography (PGC) has been used for investigations of a polymethyl methacrylate-polystyrene-polymethyl methacrylate block copolymer. Continuous distribution of the polymer (40-mg sample) was attained according to the content of the styrene and methyl methacrylate units and of the block copolymer and according to the composition of the copolymer as functions of the hydrodynamic radius of the macromolecules. The polymer was subjected to a preliminary fractionation with an analytical gel chromatograph. The fractions were investigated by TLC, which permitted the separation of the block copolymer and the homopolymers. The composition of the fractions obtained by GPC and TLC was determined by PGC. As a result, it was possible to establish the composition of the block copolymer and its ratio to polymethyl methacrylate in each fraction. This investigation was based on a combination of highly effective fractionation by chromatographic methods with precise quantitative ratios obtained from Benoit's universal calibration graph and from determinations of the composition of the polymer fractions by PGC. The mechanism of the TLC of polymers, including the appearance of artefacts that distort the results of analysis, is also discussed.

Chromatography↗

PubMed1999

A technique for rigid fixation of methyl methacrylate cranioplasty: the vault-locking method.

BACKGROUND: Current treatment of difficult to reach lesions of the central nervous system favors extensive bone removal for improved visualization and access with minimal brain retraction. Particularly in the posterior fossa, bone is often removed piecemeal, and a standard craniotomy flap is not always available for simple reattachment. Cranioplasty with methyl methacrylate is used to provide cosmesis and neural protection. A method for the fixation of methyl methacrylate cranioplasty is described, and the results of technique application in 30 patients during a 14-month period are reported. METHODS: A series of notches are burred in the cancellous margin of the surrounding cranium, preserving the inner and outer tables. Methyl methacrylate is applied to the defect. Overflow of methyl methacrylate into the notches assures solid fixation. The resultant construct resembles the locking mechanism of a bank vault. No mesh, wire, or miniplates are required. Prolene buttresses may be placed through the outer table of the notches to identify their location, should removal of the plasty be required. Removal of the outer table over the notches facilitates rapid removal. RESULTS: Solid plasty and good cosmesis occurred in all patients. There were no infections or complications related to this technique. CONCLUSIONS: Firm fixation, molding and hardening in situ, and technical ease are potential advantages over established methods of cranioplasty.

Adult↗

PubMed1999

A method for processing fluorescent labelled tissue into methacrylate: a qualitative comparison of four tracers.

A technique for preserving fluorescence in retrogradely labelled neurons embedded in resin was developed. Four retrograde tracers were tested, Fast Blue (FB); Diamidino Yellow (DY); tetramethylrhodamine dextran (fluoro-ruby) (TMRD) and fluorescein dextran (fluoro-emerald) (FD). These tracers were applied to the cut end of the sciatic nerves in rats either by: (a) direct application of tracer crystals, or (b) dipping the nerve into an aqueous solution containing the tracer. Each lumbar spinal cord was removed and dehydrated by one of two methods: (a) conventional alcohol dehydration, or (b) dehydration through a graded series of aqueous methacrylate infiltration solutions (inert dehydration). Specimens were embedded in methacrylate and horizontal sections cut. The location of labelled motoneurons was mapped using a fluorescence microscope. Direct application of tracer crystals labelled more motoneurons than dipping. Fast Blue labelled considerably more motoneurons than tetramethylrhodamine. Labelling by all tracers was retained following methacrylate embedding. Fast Blue and Diamidino Yellow required inert dehydration, while tetramethylrhodamine dextran and fluorescein dextran were preserved using conventional dehydration. These results indicate that tissue labelled with commonly used fluorescent tracers can be processed and embedded in methacrylate, thereby permitting quantitative analysis by modern stereological methods.

Animals↗

PubMed2025

Chemoselective Tagging of Protein Methacrylation.

Protein lysine methacrylation (Kmea) is a recently identified post-translational modification whose biofunction remains poorly understood. Until now, there has been no chemical labeling method for Kmea modification, which has severely hindered the discovery and functional studies of methacrylated proteins. Here, we developed a photocatalytic thia-Michael reaction system for the chemoselective labeling of protein methacrylation. By exploiting the dual effect of steric hindrance and the stability of the generated C-center radical, the reaction interference of the structural isomer crotonylation can be efficiently avoided. Based on this reaction, a multifunctional water-soluble benzenethiol-azide probe azDSH was designed and synthesized, and a workflow for the specific labeling, enrichment, and identification of Kmea proteins was developed. Proteomic identification of histone and nuclear protein extracts and whole-cell lysate revealed a number of novel Kmea proteins and modification sites besides histones, such as HMGB1, TdIF2, UHRF1, HNRPD, BRWD1, TAF1, TACC1, and SETD3, providing new targets for the study of epigenetic regulation. This study provides an effective method for the analysis of protein methacrylation modifications in biological systems.

Humans↗

PubMed2006

Self-organization-induced three-dimensional honeycomb pattern in structure-controlled bulky methacrylate polymers: Synthesis, morphology, and mechanism of pore formation.

Here we report, for the first time, a novel molecular design for three-dimensional honeycomb structures through a self-organization of hydrogen-bonded bulky anchoring group in a methacrylic polymer backbone. The polymerizable monomer design includes a methacrylic double bond linked to various hydrophobic anchoring units such as ethane, n-decane, tricyclodecane (TCD), and adamantane via a hydrogen-bonded cycloaliphatic urethane linkage. The structures of the polymers were confirmed by nuclear magnetic resonance (NMR) and the molecular weights of the polymer were determined by gel permeation chromatography (GPC). The methacrylate polymers having tricyclodecane and adamantane bulky anchoring groups self-organized to produce three-dimensional honeycomb patterns in tetrahydrofuran-water solvent mixture at ambient conditions, whereas its linear analogues (ethane, n-decane) failed to produce any micropattern. The scanning electron microscopy (SEM) analysis of the above-prepared polymer films revealed that the structure of the polymer played a major role in the formation of the honeycomb patterns. The solution Fourier transform infrared (FTIR) measurements confirmed that the bulky tricyclodecane and adamantane polymers have strong hydrogen-bonding interaction compared to that of their linear analogues, which is the driving force for the micropatterns. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) analysis of the bulky polymers revealed that the polymers exist as vesicles or micelles in the solution, which leads to the formation of the honeycomb pattern. The honeycomb pattern formation in the bulky polymer systems suggests that two cooperative factors such as hydrogen-bonding interaction and hydrophobicity of bulky anchoring units are necessary to induce three-dimensional honeycomb structures. To investigate the effect of molecular weights and its distribution on the self-organization process, both benzoyl peroxide (BPO) initiated free radical and atom transfer radical polymerization (ATRP) techniques were employed for the polymerization. Micropores formed irrespective of differences in molecular weight and polydispersity index (PDI); however, the pore size distribution was influenced by both molecular weights and PDI. Low molecular weight samples afforded polydisperse pores with the ATRP samples with more narrow PDI producing pores with large dimensions. The approach has also been investigated for polystyrene-bulky methacrylic copolymer, and the results revealed that uniform honeycomb patterns were produced for copolymers having more than 50 mol % incorporation of bulky units.

Journal Article↗

PubMed2004

Association behavior of fluorine-containing and non-fluorine-containing methacrylate-based amphiphilic diblock copolymer in aqueous media.

Fluorine-containing amphiphilic block copolymers, poly(sodium methacrylate)-block-poly(nonafluorohexyl methacrylate) (NaMAm-b-NFHMAn) (m:n = 61:12, 72:33, 64:57), and the corresponding non-fluorine-containing amphiphilic block copolymer, poly(sodium methacrylate)-block-poly(hexyl methacrylate) (NaMAm-b-HMAn) (m:n = 64:10, 69:37, 67:50), were synthesized. Both polyNaMA-b-polyNFHMA and polyNaMA-b-polyHMA formed micelles above critical micelle concentrations, (cmc's), around 3 x 10(-5) to 1 x 10(-4) mol/L, while neither polymer decreased surface tension of aqueous solutions. The size and shape of the micelles were examined by dynamic light scattering, small-angle neutron scattering, and small-angle X-ray scattering. PolyNaMA-b-polyHMA appeared to form only spherical micelles, while polyNaMA-b-polyNFHMA with a long NFHMA segment formed both spherical and rodlike micelles. The micelles of fluorine-containing block copolymers were obviously larger than those of non-fluorine-containing block copolymers with the same chain length and the same hydrophilic/hydrophobic chain ratio. The fluorine-containing block copolymer selectively solubilized fluorinated dye into the water phase when a mixture of decafluorobiphenyl and 2,6-dimethylnaphthalene was added to the micelle solution.

Journal Article↗

PubMed2006

Composition-tunable properties of amphiphilic comb copolymers containing protected methacrylic acid groups for multicomponent protein patterning.

Methods to micropattern multiple protein components on surfaces under mild conditions are of interest for biosensing, proteomics, and fundamental studies in cell biology. Here, we report on the composition-dependent thin-film solubility behavior of o-nitrobenzyl methacrylate (oNBMA, a protected form of methacrylic acid)/methyl methacrylate (MMA)/poly(ethylene glycol) methacrylate (PEGMA) random terpolymers, materials which are promising as aqueous-processible photoresists. Over a broad range of terpolymer compositions, these materials formed initially water-insoluble films, which, upon UV irradiation, rapidly dissolved in aqueous solutions above a critical pH. This threshold pH ranged from approximately 5-7 depending upon the copolymer composition and decreased as the relative ratio of MMA to PEGMA in the copolymers decreased. In addition, in a narrow window of compositions near 35:0:65 oNBMA/MMA/PEGMA (wt ratio), an inverse behavior was observed: thin films that were initially water soluble became kinetically stable in aqueous solutions after UV exposure. The time for these films to completely dissolve was hours rather than seconds, and the rate of dissolution was both temperature- and pH-dependent. This behavior is consistent with a transient stability imparted by inter- and intramolecular hydrogen bonding in the film. Using copolymers of this composition as negative tone photoresists, we demonstrated patterning of two proteins into two discrete regions of a surface. The selective solubility of the resist copolymer allows the entire patterning process to be completed using only biological buffers as solvents and across a temperature range between 4 and 37 degrees C without subjecting either protein to ultraviolet irradiation or dehydration. These materials are thus of interest for complex surface photopatterning under mild aqueous conditions.

Journal Article↗

PubMed1997

Heterocyclic methacrylates for clinical applications-further studies of water sorption.

The room temperature polymerizing system comprising poly(ethyl methacrylate)-tetra hydrofurfuryl methacrylate (PEM/THFMA) has potential in orthopaedic and dental applications, and earlier work has shown it to have unusual water absorption characteristics. This aspect has been studied in further detail, by studying the water absorption behaviour from some biological solutions, and the effect of the addition of an antibiotic (gentamicin). For comparison purposes, a parallel system whereby tetrahydrofuryl methacrylate was replaced by hydroxyethyl methacrylate (PEM/HEMA), was studied. In the case of PEM/THFMA, water uptake was substantially reduced when absorption was carried out from solutions (from about 30% in water to about 1.5% in solutions of higher concentrations), and the corresponding diffusion coefficient increased (by a factor of several hundred). The addition of gentamicin increased uptake, but the extent of increase also decreased in solutions. It was concluded that uptake was related to the osmolarity of the external solution, and also on the presence of osmotic sites within the polymer; hence the uptake process appears to be governed by chemical potential considerations. At the higher uptakes, there was evidence of water clusters. In marked contrast, the uptake by the PEM/HEMA system was independent of the osmolarity of the external solutions, presumably due to the hydrophilic nature of HEMA.

Journal Article↗

PubMed1997

Control of ethyl methacrylate exposures during the application of artificial fingernails.

In 1990 six cases of physician-diagnosed occupational asthma in cosmetologists working with artificial fingernails prompted the Colorado Department of Health to request the assistance of National Institute for Occupational Safety and Health (NIOSH) researchers in the evaluation and control of nail salon technician exposure. A commercially available recirculating downdraft table with charcoal filters was purchased and evaluated. Researchers from NIOSH made modifications to the table that included increasing the downdraft air volume; enlarging the plenum for more consistent airflow rates at the face of the table; removing the charcoal filters while incorporating a ventilation system to the outdoors; and putting an extension around the duct leading to the perforated plate at the downdraft face of the table. An evaluation was performed using the following two configurations: the modified table with the downdraft ventilation on (vented) and without the downdraft ventilation on (unvented). Each of the two configurations was sampled for 3 days in random order. Testing included the use of XAD-2 solid sorbent tubes for determining ethyl methacrylate and methyl methacrylate concentrations. Relative concentrations of organics were examined and used to analyze work practices. The geometric mean ethyl methacrylate exposure for personal breathing zone samples when using the modified table for approximately 6 hours was 0.6 ppm; when using the unventilated conventional table, the geometric mean exposure was 8.7 ppm. The difference in the values is statistically significant (p = 0.0045). Methyl methacrylate concentrations were nondetectable on all sorbent tubes.

Air Pollutants, Occupational↗

PubMed1978

Intraarticular methyl methacrylate: a complication of hip surgery.

Methyl methacrylate, used as a grout during hip arthroplasty, can inadvertently become lodged between acetabular and femoral components during surgery. After resumption of ambulation, crescentic fragments may extrude into the pseudocapsule. If mobile methyl methacrylate fragments lodge within the joint, late surgical failure may result because of methyl methacrylate's abrasive character. Two cases of total hip replacement and one case of femoral arthroplasty are reported in which intraarticular methyl methacrylate was identified retrospectively; all three patients remain asymptomatic at the time of the report.

Aged↗

PubMed1994

Absence of mutagenicity in peripheral lymphocytes of workers occupationally exposed to methyl methacrylate.

Chromosome aberration rates and sister chromatid exchange frequency were examined in the peripheral lymphocytes of 38 male workers who were engaged in organic glass production and exposed to methyl methacrylate (MMA) vapors at the concentrations of 0.9 ppm to 71.9 ppm. The results were compared with the findings in the concurrent nonexposed male subjects. Comparison of the exposed group with the nonexposed controls showed that there were no exposure-related changes in chromosome aberration rate. SCE frequency was higher in the exposed group than in the controls, but this was considered to be due to higher ages of the former group than that of the latter. In fact, selection of nonsmokers and further classification of the exposed nonsmokers into two groups of those with exposure below and above a median MMA concentration (ca. 4 ppm) failed to show any difference among the three nonsmoking groups in cytogenetic parameters, or any dose-dependency. The present results, although in a limited number of subjects, indicate that occupational methyl methacrylate exposure under the conditions studied is not associated with mutagenicity. This conclusion confirms the absence of mutagenicity of methyl methacrylate in humans, and is in general agreement with a majority of the results of studies on mutagenicity in vitro, animal carcinogenicity and occupational cancer epidemiology of methyl methacrylate.

Adult↗

PubMed1991

Clipping of an aneurysm 20 years after encasement with methyl methacrylate. Case report.

A variety of agents have been used to coat aneurysms as an alternative to clipping. These agents were employed more frequently prior to the routine use of the operating microscope and the presently available variety of aneurysm clips. One such coating agent is methyl methacrylate. This report describes a patient with an anterior communicating aneurysm that rebled 20 years after being encased in methyl methacrylate. At operation, the pulsating aneurysm had eroded the adjacent layer of methyl methacrylate, creating a small intervening space. This space allowed removal under the microscope (with a high-speed air drill and a diamond bit) of the methyl methacrylate from the anterior cerebral arteries and aneurysm, exposing it for definitive clip placement. The feasibility of clipping encased aneurysms is discussed.

Colloids↗

PubMed2001

[Application of wide-bore capillary gas chromatography in the synthesis of special esters of methacrylic acid].

A simple, rapid and accurate method for separating and analysing components in the synthesis of special esters of methacrylic acid by gas chromatography is reported. An SE-54 wide-bore capillary column of 50 m x 0.53 mm i.d. x 0.6 microns was used. The esters include dimethylaminoethyl methacrylate(DMAM), n-butyl methacrylate(BMA) and ethylene glycol dimethacrylate(EGDMA). Crude materials such as methyl methacrylate(MMA) and N, N-dimethyl ethanol amine (DMEA) were also analysed. The recoveries were 99.71%-102.89%, and the RSDs of the main components were below 0.1%. The method can be used to control the production of the esters.

English Abstract↗

PubMed1996

[Bronchial asthma with inflammation of the nose mucous membrane induced by occupational exposure to methyl methacrylate in a dental technician ].

A case report of a 40-year-old female dental technician with a 13-year history of methyl methacrylate exposure is presented. Symptoms of dyspnea, wheezing, coughing and rhinorrhea occurred 6-8 months after the first occupational contact with methyl-methacrylate containing substances. Skin tests performed with a battery of common allergens produced negative results. While performing a provocation test with methyl-methacrylate, the patient developed severe stridor and dyspnea with concomitant decrease in I second forced expiratory volume (FEV1) and peak respiratory flow (PEF). The increase in leukocytes, eosinophils, basophils, albumin, eosinophil cationic protein (ECP) and mast cell tryptase occurred in nasal lavage fluid after bronchial provocation test. The authors conclude that methyl-methacrylate may cause asthma (probably non-atopic) in persons occupationally exposed to its effect.

Adult↗

PubMed1974

Diffusion of anti-tumor drugs through membranes from hydrophilic methacrylate gels.

Permeation parameters of four anti-tumor drugs across membranes prepared from hydrophilic methacrylate gels were measured and compared with the permeation of NaCl. It was found that by increasing the ratio of butyl methacrylate (BMA) to hydroxyethyl methacrylate (HEMA), the rate of diffusion can be lowered to practically zero at 20% BMA. However, this decrease is different with various drugs due to the interaction of the drug with the gel. Differences by a factor of two were found in our set of drugs. Therefore, each new drug should be tested in this way. In addition a routine testing of dialysing devices by an NaCl solution is suggested as a method for detecting technological imperfections and calibrating the deviations from standard parameters. A chemical modification of the membrane is recommended as the best way for controlling the permeation rate.

Acrylates↗

PubMed2004

Evaluation of dental restorative composites containing polyhedral oligomeric silsesquioxane methacrylate.

OBJECTIVES: The aim of this study was to explore novel polymeric dental restorative composites, in which polyhedral oligomeric silsesquioxane methacrylate monomer (POSS-MA) was used to partially (or completely) replace the commonly used base monomer 2,2'-bis-[4-(methacryloxypropoxy)-phenyl]-propane (Bis-GMA). METHODS: The composites were cured (hardened) by photo-initiated free radical polymerization. Mechanical properties (i.e. flexural strength, Young's modulus and diametral tensile strength) of the composites were tested by a universal mechanical testing machine; photopolymerization induced volumetric shrinkage was measured using a mercury dilatometer; and near infrared (NIR) technique was used to study the degree of methacrylate double bond conversion and photopolymerization rate. RESULTS: Small percentage POSS-MA substitution of Bis-GMA (i.e. mass fraction of 10% or less) in the resin system improved the mechanical properties of the composites; while large amount substitution led to less desirable mechanical properties, lower methacrylate double bond conversion, and slower photopolymerization rate. Statistical examinations showed the maximum flexural strength of the composites occurred when 10% (mass fraction) of Bis-GMA was replaced by POSS-MA, while the highest modulus occurred when the mass fraction of POSS-MA was 2%. SIGNIFICANCE: Polymeric dental restorative composites with improved mechanical properties may be designed by judicious choice of monomer (POSS-MA, Bis-GMA and TEGDMA) compositions.

Bisphenol A-Glycidyl Methacrylate↗