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PubMed1987

Comparison of polyacrylamide and agarose support media for detection of oligoclonal IgG bands in CSF.

Parallel samples of cerebrospinal fluid (CSF) from 120 patients clinically suspected of having multiple sclerosis were electrophoresed using agarose or 7% polyacrylamide. 57 samples showed oligoclonal IgG patterns in polyacrylamide but only 34 showed bands after concentration and electrophoresis in agarose. The concentrations of IgG and albumin were also measured in each sample and IgG/albumin ratios calculated. The sensitivities of the three methods for the detection of intrathecally synthesised IgG were compared. Electrophoresis in 7% polyacrylamide gave the highest proportion of significant results. In an attempt to increase the sensitivity of the agarose method, silver staining was performed on unconcentrated samples run in agarose. This did not alter the pattern of electrophoresis in samples containing oligoclonal IgG, but the sensitivity of the technique was lower than that of polyacrylamide.

Electrophoresis↗
PubMed1980

Efficient transfer of highly resolved small DNA fragments from polyacrylamide gels to DBM paper.

A procedure is described that combines high resolution of small DNA molecules (10 to 250 bases) with high transfer efficiency from polyacrylamide gels to diazobenzyloxymethyl (DBM) paper. The DNA fragments are separated electrophoretically in denaturing or nondenaturing step gels. These consist of a short gel of relatively high polyacrylamide concentration (8%) above a long gel of relatively low polyacrylamide concentration (4%). Step gels permit a high resolution of small DNA fragments in gels of sufficiently low polyacrylamide concentration from which efficient transfer to DBM paper is feasible. The combination of the step gel with a short treatment of the gel before transfer ensures a high transfer efficiency. As much as 30% and 50% of the DNA applied to nondenaturing and denaturing gels, respectively, are bound covalently to the DBM-paper. Optimal conditions for hybridization to DBM-linked DNA molecules of 30 to 250 base length are described.

DNA↗
PubMed1993

Electrophoresis of DNA in ultrathin planar-format linear polyacrylamide.

Linear or un-cross-linked polyacrylamides have been employed successfully in the field of capillary electrophoresis for the separation of nucleic acids. Typical acrylamide concentrations for those applications range from 3% to 14% (wt/vol), with consistencies ranging from virtually liquid to moderately viscous. Due to the absence of cross-links, and the relatively fluid nature of linear polyacrylamide at typically employed concentrations, its use in planar (slab) gel electrophoresis has been overlooked. We describe herein the application of ultrathin (100 microns) high-viscosity slabs of linear polyacrylamide to planar electrophoresis of nucleic acid fragments. The approach we describe is rapid and yields high-resolution separations of nucleic acid fragments in linear polyacrylamide supports. The mobilities of DNA fragments of various lengths in a range of concentrations of linear polymer are compared with those observed for conventional cross-linked gels. The reptative migration of larger DNA fragments in linear polymers is predictable from the models derived from work with cross-linked acrylamide and agarose. The migration of smaller fragments, however, is not entirely predicted by the Ogston model. The relative mobilities observed for very small DNA fragments are approximately half those predicted by the Ogston regimen.

Acrylamide↗
PubMed2003

Tests for the depolymerization of polyacrylamides as a potential source of acrylamide in heated foods.

This study was conducted to test the possibility that polyacrylamides used in agriculture may contribute to acrylamide formation in heated foods by thermal depolymerization. Two samples of polyacrylamide with low molecular weights of 1.5 and 10 kDa were used to test for in-chain and end-chain depolymerization. They were added as aqueous solutions to filter paper for heating in a drying/dry environment and added to a cooking oil for heating in a fatty environment. The heating conditions were 175 degrees C for 15 and 30 min, respectively. Both regimens were tested in the absence and presence of the redox-active metal ions Fe(III) and Cu(II), and all tests were conducted without the exclusion of atmospheric oxygen. There was no evidence of any significant depolymerization of polyacrylamide to free acrylamide monomer, <0.04%. In fact, residual levels of acrylamide present already in the low molecular weight polymers were seen to fall by 50-80% on heating. Consequently, it is concluded that even if polyacrylamides were to contaminate agricultural crops and foods derived therefrom (which itself is an unproven suggestion), there is no evidence that the polymers would depolymerize on heating of the food to form acrylamide in any significant amount.

Acrylamide↗
PubMedDate not supplied

Measurement of the thermal conductivity of polyacrylamide tissue-equivalent material.

The purpose of this work was to measure the thermal conductivity of polyacrylamide (PAG) and compare it with previously reported values. Polyacrylamide phantoms play an important role in the development of hyperthermia and high-temperature thermal therapies based on electromagnetic (EM) radiation by providing a material that mimics the electrical and thermal properties of human tissue. The thermal properties of PAG have, up until now, not been thoroughly investigated and at least two significantly different values have been published. In this study, the thermal conductivity of polyacrylamide was measured from the steady state temperature drop across samples exposed to a known heat flux. The measured conductivity was 0.56 +/- 0.047 W m(-1) degrees C(-1). To validate the correct set of thermal properties for polyacrylamide, simple heating experiments were performed in a PAG phantom and then simulated using a finite element numerical model that incorporated the measured thermal conductivity along with literature values for specific heat and density. Temperature predictions from the model agreed with average temperatures measured in the phantom to within 1 SD of the measured temperatures.

Acrylic Resins↗
PubMed1993

Design and synthesis of polyacrylamide-based oligonucleotide supports for use in nucleic acid diagnostics.

Polyacrylamide supports, in a range of pore sizes, were investigated as nucleic acid affinity matrices for the detection of target DNA or RNA sequences using a sandwich hybridization format. Bromoacetyl and thiol oligonucleotide derivatives were covalently linked to sulfhydryl- and bromoacetyl-polyacrylamide supports with greater than 95% end-attachment efficiencies. These polyacrylamide-oligonucleotide supports were further derivatized with anionic residues to provide multi-functional supports which show low non-specific binding for non-complementary nucleic acids. While all the polyacrylamide-oligonucleotide supports capture complementary oligonucleotides with high affinity, the pore size was found to be a critical parameter in sandwich hybridization reactions. The superior hybridization characteristics of the Trisacryl support was ascribed to a combination of its macroporous nature, hydrophilicity and the terminal attachment of its capture oligonucleotides.

Acetates↗
PubMed1975

Proton magnetic resonance studies of the binding of an anionic surfactant with a benzene ring to a protein polypeptide with special reference to SDS-polyacrylamide gel electrophoresis.

The binding of an anionic surfactant to a protein polypeptide has been studied by the proton magnetic resonance (PMR) technique to form a part of our studies on the principles of SDS-polyacrylamide gel electrophoresis. Sodium 4-(p-butylphenyl) butane-1-sulfonate (CH3-(CH2)3-0-(CH2)4-SO3-Na+) was employed as an anionic surfactant, and reduced and carbosyamidomethylated (RCAM) bovine serum albumin as a typical protein polypeptide. The binding isotherm of the surfactant to RCAM bovine serum albumin was similar to that of sodium dodecyl sulfate (SDS). The surfactant could replace SDS in SDS-polyacrylamide gel electrophoresis without affecting the wellknown mode of spearation of protein bands. These results gave a sound basis for the assumption that the investigation of the complex between a surfactant with a benzene ring and RCAM bovine serum albumin would provide useful knowledge concerning the principles of SDS-polyacrylamide gel electrophoresis. Aggregation of the aromatic surfactant necessarily brings benzene rings together. A benzene ring is a strong source of the ring current effect on chemical shifts in nuclear magnetic resonance (NMR). Chemical shifts of the surfactant in NMR are, therefore, sensitive to whether the surfactant molecules are single-molecularly dissolved or aggregated. Full advantage was taken of the above fact in the present PMR study of the binding of the surfactant to RCAM bovine serum albumin. The chemical shifts of the phenyl and methyl protons both for the single-molecular and micellar aggregated states were estimated from measurements of the shifts as a function of the surfactant concentration. They shifted to a higher magnetic field on micelle formation, due to the increase of the ring current effect. Corresponding measurements for the complex between the surfactant and RCAM bovine serum albumin gave estimates of the chemical shifts of the phenyl and methyl groups of the surfactant bound to the protein polypeptide. They were found to shift to a magnetic field somewhat higher than that for the micellar state throughout the concentration range of the surfactant examined. These results strongly suggest that the surfactant molecules bind to the protein polypeptide in the form of micelle-like clusters, and that PMR of the groups are further influenced by the diagmagnetic effect of the protein polypeptide present as a core. No appreciable change in the mode of binding, corresponding to the steep increase in the amount of binding in the binding isotherm, was observed from the PMR studies. Taking the observed similarity between SDS and the aromatic surfactant in the binding and the gel electrophoresis into consideration, the present results strongly suggest that SDS also binds to protein polypeptides in the form of micelle-like clusters under the conditions of SDS-polyacrylamide gel electrophoreses, and support our "necklace model".

Benzene Derivatives↗
PubMed1983

Analysis of apolipoproteins B100 and B48 by sodium dodecyl sulfate polyacrylamide gradient gel electrophoresis.

Apolipoproteins B100 and B48 in human and rat plasma were studied by using sodium dodecyl sulfate (SDS) polyacrylamide gradient gel electrophoresis. On SDS gradient gel electrophoresis, human and rat apoprotein B100 co-migrated and had an apparent Mr equal 258,000 +/- 12,000. Human and rat apoprotein B48 had an apparent Mr equal 189,000 +/- 6,000. The molecular weight of human apoprotein B100 determined by sedimentation equilibrium analysis was 270,000 +/- 20,000, which was similar to the value determined by SDS gradient gel electrophoresis. However, on SDS polyacrylamide gel electrophoresis at constant concentration, the relative migration value of human apoprotein B100 was not constant when the concentration of polyacrylamide was changed. These results indicate that SDS gradient gel electrophoresis is more suitable for the analysis of apolipoprotein B's than ordinary SDS polyacrylamide gel electrophoresis.

Animals↗
PubMed1984

Analyses of gonococcal lipopolysaccharide in whole-cell lysates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis: stable association of lipopolysaccharide with the major outer membrane protein (protein I) of Neisseria gonorrhoeae.

The lipopolysaccharide (LPS) of Neisseria gonorrhoeae whole-cell lysates and proteinase K-digested lysates was examined and compared with purified homologous LPS by a method which preferentially stains LPS in polyacrylamide gels. The silver-stained profile of gonococcal LPS in the proteinase K-digested lysate was similar to that of homologous purified LPS; however, the LPS profile in whole-cell lysates was much smaller than that of digested lysates or purified LPS. Conditions of solubilization did not affect these differences. Since it is known that LPS migrates in a unique fashion in second-dimension electrophoresis, the location of LPS in the whole-cell lysates was probed by second-dimension sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a variety of stains and radiolabels. Results from these experiments indicated a stable and reproducible association of LPS with proteins ranging between 23,000 to 36,000 in Mr, in particular major outer membrane protein I. In addition to staining with the silver method, which preferentially stains LPS, the putative LPS was resistant to digestion by proteinase K, did not stain with Coomassie brilliant blue, and was not labeled extrinsically with 125I (Iodogen method) or intrinsically with [35S]methionine. Analysis of two-dimensional gels by immunoblotting with rabbit antisera prepared from protein I bands removed from a polyacrylamide gel revealed the presence of antigens in the same area of the gel (below proteins that were 23,000 to 36,000 in Mr). Antibodies to constituents which migrated below the diagonal were essentially removed by adsorption of antisera with purified LPS, as were antibodies to homologous LPS and LPS in proteinase K-digested whole-cell lysates. Immunoblotting with a monoclonal antibody specific for LPS demonstrated reactivity of the antibody with LPS and with the protein I band. On the basis of these data, we conclude that protein I and perhaps other proteins in the whole-cell lysate are stably associated with LPS; this complex is resistant to dissociation in sodium dodecyl sulfate at high temperature (approximately 100 degrees C) but does, for unknown reasons, dissociate with electrophoresis in the second dimension. The association of LPS with protein antigens in sodium dodecyl sulfate-polyacrylamide gels adds another dimension of complexity to analysis of these antigens by immunoelectroblotting. Furthermore, the tight association of LPS with the major outer membrane protein I may alter the nature of the immune response generated by "purified" protein I vaccine antigens. The possible role of protein-LPS complexes in the pathogenesis of gonorrhea is discussed.

Bacterial Outer Membrane Proteins↗
PubMed1986

Catalases, peroxidases, and superoxide dismutases in Mycobacterium leprae and other mycobacteria studied by crossed immunoelectrophoresis and polyacrylamide gel electrophoresis.

The five mycobacteria Mycobacterium lepraemurium, M. leprae, M. bovis BCG, M. smegmatis, and M. intracellulare were studied. Catalase and peroxidase activities were demonstrated in polyacrylamide and crossed immunoelectrophoresis gels for M. lepraemurium, M. intracellulare, and BCG, but not for M. leprae. Peroxidase and catalase activities were associated with the same precipitate line in crossed immunoelectrophoresis for M. lepraemurium, M. intracellulare, and BCG, showing that in these mycobacteria the two enzyme activities resided in the same molecule. M. smegmatis peroxidase and catalase activities were closely associated on polyacrylamide gel electrophoresis, but on the crossed immunoelectrophoresis catalase and peroxidase activities were associated with two different precipitate lines. Catalases without peroxidase activity were demonstrated in crossed immunoelectrophoresis and polyacrylamide gel electrophoresis in M. intracellulare and M. smegmatis. The catalase without peroxidase activity in M. intracellulare was heat resistant and therefore classified as an m-catalase. In M. smegmatis the catalase without peroxidase activity was only partially heat resistant. All of the catalases with peroxidase activity were heat-sensitive t-catalases. Superoxide dismutase activity in the crossed immunoelectrophoresis was associated with the M. leprae antigen no. 4 and with cross-reacting antigens in the other mycobacteria studied. Several superoxide dismutases were demonstrated in Mycobacterium duvalii. They were antigenically different from the other superoxide dismutases in this study, as shown by lack of reactivity with a monospecific antibody to M. lepraemurium superoxide dismutase. Molecular weights were estimated for all the enzymes in this study by sodium dodecyl sulfate-polyacrylamide gels.

Catalase↗
PubMed1990

Modification of the silver staining technique to detect lipopolysaccharide in polyacrylamide gels.

A silver staining method used routinely for detecting bacterial lipopolysaccharide (LPS) in sodium dodecyl sulfate-polyacrylamide gels (C. Tsai and E. Frasch, Anal. Biochem. 119:115-119, 1982) appeared to be inappropriate for visualizing certain LPS preparations. It did not stain S-form fractions of polyagglutinable Pseudomonas aeruginosa LPS or several partly deacylated (alkali-treated) S-form LPS after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, these LPS preparations could be detected by anti-LPS sera after electroblotting onto nitrocellulose, thereby confirming their integrity and presence in the polyacrylamide gel. This is because LPS fractions containing a low number of fatty acids are washed out of the gel during the initial fixing step (40% ethanol-4% acetic acid, overnight). By omitting this fixing step, which was originally developed for detecting proteins, and by increasing the LPS oxidation time (from 5 to 20 min), we restored the ability to detect LPS fractions that otherwise would not be stained. These modifications did not affect the detection of other S- and R-form LPSs. Thus, differences in the number of fatty acids present in polyagglutinable P. aeruginosa LPS may result in a selective loss of fatty acid-deficient S-form LPS in these apparent R-form LPS preparations. This modified procedure provides a fast, simple, and sensitive way to analyze LPS in polyacrylamide gels despite the number of acyl groups present.

Electrophoresis, Polyacrylamide Gel↗
PubMed1979

An evaluation of a simple polyacrylamide gel electrophoresis system for lipoproteins and its use for the characterisation of hyperlipoproteinaemia.

The use of polyacrylamide gel electrophoresis as a screening procedure for the characterisation of hyperlipoproteinaemia is described. Sixty-one samples were investigated and classified by four different methods: (1) chemical profile derived from visual appearance and estimation of total cholesterol and triglyceride; (2) 'SML' profile by nephelometry; (3) electrophoresis on agarose gel; and (4) electrophoresis on polyacrylamide gel. Polyacrylamide gel electrophoresis showed the closest correlation with the chemical profile when compared with the other two methods. Polyacrylamide gel electrophoresis was found to be a rapid, reliable, and satisfactory procedure for plasma lipoprotein phenotyping.

Blood Protein Electrophoresis↗
PubMedDate not supplied

Toxicity of polyacrylamide and acrylamide monomer.

The purpose of this paper is to present information gathered regarding, in general, the physical characteristics, and, in particular, the possible toxic nature of polyacrylamide A short discussion of the properties and toxicity of the acrylamide monomer is also included. The United States government, specifically the Food and Drug Administration and the Environmental Protection Agency, already regulates several uses of polyacrylamide; criteria and standards have been established based on numerous toxicological studies of both polyacrylamide and acrylamide. These studies are reviewed and summarized. The regulations generally restrict both the amount of residual acrylamide monomer in the polyacrylamide and the amount of polymer that may be used in the specified application. By imposing this type of restriction, a maximum limit on the amount of acrylamide in contact with food or drinking water can be indirectly achieved.

Acrylic Resins↗
PubMed1979

A viscosity model of polyacrylamide gel electrophoresis.

In current theories of polyacrylamide gel electrophoresis, the idea prevails that molecular sieving relies on different accessibility of volume fractions and of cross-sectional area fractions (denoted "pores") to different-sized ions due to the effect of "geometric exclusion". This correlates with the assumption that all elements of a polyacrylamide network occupy fixed and unchangeable positions thus forcing colliding macro-ions to diffuse laterally in order to find an "accessible pore" and to resume motion in direction of the electrical field. However, the alternative conception would be equally well justified, i.e. the assumption that polyacrylamide chains represent smooth obstacles cleared aside under the electrokinetic pressure of a macro-ion. This explanation would even be preferable with respect to the molecular sieving effects occurring in solutions of "liquid polyacrylamide". Yet no theory exists as to describe such effects in quantitative terms. In the present article, a parameter is defined and discussed, which can be estimated by experiment, and which seems to be apt to characterize local resistivity of polymer structures against dislocation and deformation: the "fractional specific resistance". Definition of this parameter is based on the model of a "viscosity-emulsion" composed of two interpenetrating liquid compartments which are characterized by different levels of hydrodynamic friction and the spatial dimensions of which are inferred from Ogston's theory. This concept of "localized viscosity" may also serve as a link between theories of molecular sieving and of "macroscopic viscosity" of flexible polymers. The data of Morris, formerly taken as verifications of the "rigid-pore" concept, are now interpreted in terms of four factors responsible for sizediscrimination: collision frequency, duration of single contacts, size-dependent frictional force, and the extent of cooperation among fibres, due to crosslinking and to simultanous contacts of several fibres to a single macro-ion. Some functions relevant for problems of molecular weight determination by gel electrophoresis are discussed in relation to the suggested model.

Acrylamides↗
PubMedDate not supplied

Micropreparative protein isolation from polyacrylamide gels following detection by high-resolution dynamic imaging: application to microsequencing.

Polyacrylamide gel electrophoresis is a high-resolving technique for separating proteins. Until recently, its use as a micro-preparative method for isolating microgram amounts of protein in a form suitable for structural analysis was limited by the difficulty in recovering material from the polyacrylamide matrix. This problem has been largely overcome by the development of chemically inert membranes that retain proteins after electroblotting from the polyacrylamide gel. The immobilized proteins are suitable for chemical identification by direct microsequence analysis. Nevertheless, the overall recoveries of proteins using this electrotransfer/blotting approach are low (28%-30%). This paper describes a phase-contrast technique that allows the visualization of proteins during the polyacrylamide gel electrophoresis. This approach is suitable for the quantitative detection of proteins. Since no fixing/staining step is employed, proteins can be recovered in high yield (50%-65%), by passive elution, in a form suitable for microsequence analysis. Methods and strategies for obtaining internal amino acid sequence information from proteins recovered from gels after visualization by high-resolution dynamic imaging are discussed.

Amino Acid Sequence↗
PubMed1991

Efficacy of polyacrylamide vs. sodium hyaluronate in cataract surgery.

A prospective randomized study was conducted in 137 patients who underwent cataract surgery and implantation of a polymethylmethacrylate intraocular lens with either polyacrylamide (Orcolon) (68 patients) or sodium hyaluronate (Healon) (69 patients) as the viscoelastic material. Both viscoelastics were aspirated at the end of surgery. Patients were examined before surgery and 1 and 14 days after surgery. Endothelial cell counts were obtained before surgery and 3 months after surgery in 34 patients (16 in the polyacrylamide group and 18 in the sodium hyaluronate group). There were no reports of a flat or shallow anterior chamber intraoperatively in either group. There was no statistically significant difference between the two groups in the incidence of corneal edema or iritis on any visit or in endothelial cell loss. Although there was a significant reduction in intraocular pressure across postoperative visits for the overall sample, there was no significant difference in pressure between the polyacrylamide and sodium hyaluronate groups. The results indicate that no untoward effects on corneal edema, endothelial cell count, iritis or intraocular pressure are to be expected when polyacrylamide is used as an aid to cataract surgery.

Acrylic Resins↗
PubMedDate not supplied

Management for postoperative complications of breast augmentation by injected polyacrylamide hydrogel.

Polyacrylamide hydrogel, a new biomaterial, has been used for injected breast augmentation in China since 1997. A series of 30 patients with various complications after injected polyacrylamide hydrogel visited the author's department. Most of these patients had undergone injection of both breasts. The average age of the patients was 27.6 years, and the time of consultation for the complications was from 3 to 36 months postopertively. Nearly all the patients had breast lumps and other common complications including breast pain, disfigurement, and infection. Ultrasound examination showed diffuse, irregular, anechoic zones of mammary tissue. Pathologic results indicated inflammatory cell infiltration and fibrous capsular formation. An open suction technique and partial mastectomies via periareolar incisions were performed for the all patients. Most of their symptoms were relieved after removal of the polyacrylamide hydrogel. Only one patient had undergone immediate breast reconstruction with implants, whereas five patients had received breast implants secondarily via an axillary incision. The authors conclude that polyacrylamide hydrogel should be prohibited for injected breast augmentation before more scientific data are available about the long effect of the gel in breast tissue.

Acrylic Resins↗
PubMed2004

Jet injection into polyacrylamide gels: investigation of jet injection mechanics.

Jet injectors employ high-velocity liquid jets that penetrate into human skin and deposit drugs in the dermal or subdermal region. Although jet injectors have been marketed for a number of years, relatively little is known about the interactions of high-speed jets with soft materials such as skin. Using polyacrylamide gels as a model system, the mechanics of jet penetration, including the dependence of jet penetration on mechanical properties, was studied. Jets employed in a typical commercial injector, (orifice diameter: 152 microm, velocity: 170-180 m/s) were used to inject fluid into polyacrylamide gels possessing Young's moduli in the range of 0.06-0.77 MPa and hardness values in the range of 4-70 H(OO). Motion analysis of jet entry into polyacrylamide gels revealed that jet penetration can be divided into three distinct events: erosion, stagnation, and dispersion. During the erosion phase, the jet removed the gel at the impact site and led to the formation of a distinct cylindrical hole. Cessation of erosion induced a period of jet stagnation ( approximately 600 micros) characterized by constant penetration depth. This stage was followed by dispersion of the liquid into the gel. The dispersion took place by crack propagation and was nearly symmetrical with the exception of injections into 10% acrylamide (Young's modulus of 0.06 MPa). The penetration depth of the jets as well as the rate of erosion decreased with increasing Young's modulus. The mechanics of jet penetration into polyacrylamide gels provides an important tool for understanding jet injection into skin.

Acceleration↗