Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0267964 (PAA)
 2,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The quantitative and qualitative analysis of proteinuria by electrophoretic means proved to be a potent diagnostic tool for differentiation of functional renal impairment. The purpose of this study was to compare the macro scale SDS-PAGE technique, which has been used for the last two decades, with semiautomated electrophoresis using an ultrathin SDS-PAA gel with silver staining (Phast system). The new system proved to be quick and easy to handle. Separation of proteins in the range of 70-320 kD were of comparable quality to the macro scale system (unselective and selective glomerular proteinurias with 68 to 150 and 68 to 350 kD components, respectively, as well as total serum proteins), but there was considerable improvement regarding the quality and visibility of protein bands in the range of 11-70 kD. This improvement led to a new classification of micromolecular protein bands into three groups: the smallest microproteins (11-22 kD), the larger microproteins (23-40 kD) and the largest microproteins (41-68 kD). Thereby it was possible to obtain an improved definition of electrophoretic patterns of urinary proteins, which is described in detail.
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PMID:Improved classification of proteinuria by semiautomated ultrathin SDS polyacrylamide gel electrophoresis. 169 54

Protein excretion and protein fractions either according to their molecular mass or with immunological techniques were studied in the spontaneous morning urine of 17 primate species. The total protein concentration in most of the species ranges between 0.01 and 0.2 mg/ml. The pronounced proteinuria (4 mg/ml) in some south american species (Callithricidae) seems to be remarkable. By using immunoprecipitation (LC-Partigen plates), albumin could be detected in most species, alpha 1-microglobulin in some, and transferrin in few of the species. After electrophoretic separation on pre-cast 1D-micro- SDS-PAA gradient gels (8-25%, semi-automatic Phast-System) followed by CBB R-350 or silver stain respectively, in most species a protein pattern similar to human urine could be observed. As our results show, urine analysis is a suitable tool for noninvasive investigations in primates.
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PMID:[Urine proteins in primates]. 247 7

The synthesis of a terminally thiolated poly(vinyl)alcohol (PVA) grafted with Poly (acrylic acid) (PAA) side chains is described. The PVA-PAA graft polymer (PVAg) was end-tethered to silver surfaces via the terminal thiol functionality and the resultant mobile, hydrophilic polymer matrix exploited for the covalent immobilization of large quantities of polyclonal goat (anti-hIgG) antibody (IgG) with low levels of non-specific adsorption. An SPR immunosensor, fabricated with an IgG-PVA-silver interfacial layer proved capable of performing a sensitive label-free assay of human IgG antigen (hIgG) with minimal non-specific binding interference. A detection limit (DL) for hIgG from serum of 0.8 microgram/ml (5 nM) and an assay sensitivity of 0.66 ng hIgG/mm2/nM are reported.
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PMID:Covalent coupling of immunoglobulin G to a poly(vinyl)alcohol-poly(acrylic acid) graft polymer as a method for fabricating the interfacial-recognition layer of a surface plasmon resonance immunosensor. 964 73

We demonstrate the use of aqueous-based layer-by-layer (LbL) processing and in situ nanoreactor chemistry for creating polyelectrolyte multilayer (PEM) nanocomposites in which the concentration of a nanoparticle species is modulated throughout the depth of the film in a complex way. Using the in situ growth of silver nanoparticles to selectively increase the refractive index of precisely defined regions of the PEM film, we have produced a digitized rugate filter, a special type of dielectric mirror possessing many thin layers that approximate a continuous, periodic refractive index profile. The design of the digital rugate from an initial smooth index profile was aided by a computer, and construction of the device was accomplished entirely by automated means. Poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) bilayer regions within the film supported subsequent nanoreactor chemistry and created the high refractive index regions of the film, while PAH and poly(styrenesulfonate) (PSS) bilayer regions remained unmodified and served as the low index regions. Spectroscopic results obtained from the assembled device confirm the presence of a reflection band that grows in amplitude with increasing silver incorporation, reaching a peak reflectance of 75% after five silver loading and exchange cycles. The rugate structure suppresses reflection sidebands, features common to Bragg reflectors and simpler dielectric mirror designs. Cross-sectional TEM reveals nanoscale control of the size and location of silver-containing domains within the PEM film. The ability of this method to control the placement of nanoparticles within PEMs enables the inexpensive, easy production of conformable optical coatings with tunable properties. In addition, these nanocomposite films may have applications in a number of other fields where precise control of effective gradients in physical properties throughout thin films has been shown to affect the overall performance in a desirable way.
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PMID:Creating effective refractive index gradients within polyelectrolyte multilayer films: molecularly assembled rugate filters. 1587 62

Silver nanocomposite multilayer films were prepared through the in situ method. Multilayer thin films, prepared through the sequential electrostatic deposition of a positively charged third-generation poly(amidoamine) dendrimer (PAMAM) and negatively charged poly(styrenesulfonate) (PSS) and poly(acrylic acid) (PAA), were utilized as nanoreactors for the formation of silver nanoparticles. The silver ions were preorganized in layer-by-layer (LBL) films composed of PAMAM dendrimers and subsequently reduced with hydrogen to prepare the silver nanoparticles. The UV-vis spectrum and profilometer were used to characterize the regular growth of bilayers. UV-vis absorption from plasmon resonance at 435 nm and TEM images indicated the formation of the silver nanoparticles in the multilayer films. The silver nanocomposite LBL films were also constructed on the indium tin oxide-glass and investigated using cyclic voltammetry. The silver nanoparticles in the multilayer films have a stronger negative redox potential. The silver nanocomposite LBL films may have a potential application in the catalysis of reduction of 4-nitrophenol with sodium borohydride.
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PMID:Silver nanocomposite layer-by-layer films based on assembled polyelectrolyte/dendrimer. 1592 28

Infection of implanted materials by bacteria constitutes one of the most serious complications following prosthetic and implant surgery. In the present study, a new strategy for confering stainless steel with antibacterial property via the alternate deposition of quaternized polyethylenimine (PEI) or quaternized polyethylenimine-silver complex and poly(acrylic acid) (PAA) was investigated. The success of the deposition of the polyelectrolyte multilayers (PEM) and its chemical nature was investigated by static water contact angle and X-ray photoelectron spectroscopy (XPS), respectively. The antibacterial activity was assessed using Escherichia coli (E. coli, a gram-negative bacterium) and Staphylococcus aureus (S. aureus, a gram-positive bacterium). The inhibition of E. coli and S aureus growth on the surface of functionalized films was clearly shown using the LIVE/DEAD Baclight bacterial viability kits and fluorescence microscopy. The cytotoxicity of the PEM to mammalian cells, evaluated by the MTT assay, was shown to be minimal and long-term antibacterial efficacy can be maintained. These results indicate new possibilities for the use of such easily built and functionalized architectures for the functionalization of surfaces of implanted medical devices.
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PMID:In vitro antibacterial and cytotoxicity assay of multilayered polyelectrolyte-functionalized stainless steel. 1634 94

In this study, we demonstrate that 2-microm-sized Ag (microAg) powders can be used as a core material for constructing molecular sensing/recognition units operating via surface-enhanced Raman scattering (SERS). This is possible because microAg powders are very efficient substrates for both the infrared and Raman-spectroscopic characterization of molecular adsorbates prepared in a similar manner on silver surfaces; we can obtain an infrared spectrum of organic molecules adsorbed on microAg particles with a very high signal-to-noise ratio by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and the Raman spectrum of organic monolayers on powdered silver is an SERS spectrum. The agglomeration of microAg particles in a highly concentrated buffer solution could be prevented by the layer-by-layer deposition of cationic and anionic polyelectrolytes such as poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA). In fact, prior to depositing PAA and PAH, 4-aminobenzenethiol (4-ABT) was assembled on the surfaces of the microAg particles as SERS markers. Because of the presence of amine groups of 4-ABT, PAA could be readily deposited on the microAg particles. On the other hand, the outermost PAA layer could also be derivatized with biotin-derivatized poly(L-lysine). The nonspecific interaction of poly(L-lysine) with proteins could be suppressed by grafting poly(ethylene glycol) into the biotin-derivatized poly(L-lysine) molecules. On the basis of the nature of the SERS peaks of 4-ABT, it was confirmed that these biotinylated microAg powders were effective in selectively recognizing the streptavidin arrays. Because a number of different molecules can be used as SERS-marker molecules, such as probable 4-ABT, commercially available microAg powders must be a prospective material in molecular sensing/recognition, particularly via SERS.
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PMID:Silver-particle-based surface-enhanced Raman scattering spectroscopy for biomolecular sensing and recognition. 1654 10

The multilayer films of branched polyethyleneimine (BPEI) and poly(acrylic acid) (PAA) have been fabricated with the layer-by-layer (LbL) method. Two characteristic courses of the film thickness growth are observed, which are the initial exponential-like growth and the following linear growth. The variation of the COOH/COO- ratio indicates that the ionization degree of the polyelectrolyte molecules decreases at the initial stage of the multilayer buildup and then levels off after about eight bilayers. The as-prepared (BPEI/PAA)n films show a relatively smooth surface. However, great morphology changes occur after immersing these films in Cu2+ or Zn2+ solution. In the case of n > or =7, wavelike surface patterns are induced to form on the films. Both wavelength and fluctuation of these surface patterns show a systematical variation with an increase of the bilayer number. Moreover, thermal treatment can stabilize these patterns and enable the preservation of them after releasing the Cu2+ ions from the LbL films by acidic treatment. Interestingly, only Cu2+ and Zn2+ can induce the formation of such surface patterns, whereas Fe2+, Ca2+, Ag+, and Na+ cannot. This phenomenon may closely relate to the different natures of the metal ions.
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PMID:Surface patterns induced by Cu2+ ions on BPEI/PAA layer-by-layer assembly. 1728 60

We demonstrate in this work that 2-microm-sized Ag (microAg) powders can be used as a core material for constructing biomolecular sensing/recognition units operating via surface-enhanced resonance Raman scattering (SERRS). This is possible because microAg powders are very efficient substrates for both the diffuse reflectance IR and the surface-enhanced Raman scattering-SERRS spectroscopic characterization of molecular adsorbates prepared in a similar manner on silver surfaces. Besides, the agglomeration of microAg particles in a buffer solution can be prevented by the layer-by-layer deposition of cationic and anionic polyelectrolytes such as poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA). In this particular study, we used rhodamine B isothiocyanate (RhBITC) as a SERRS marker molecule, and microAg powders adsorbed consecutively with RhBITC and PAH-PAA bilayers were finally derivatized with biotinylated poly(L-lysine). On the basis of the nature of the SERRS peaks of RhBITC, those microAg powders were confirmed to selectively recognize streptavidin molecules down to concentrations of 10(-10) g mL-1. Since a number of different molecules can be used as SERS-SERRS marker molecules, the present method proves to be an invaluable tool for multiplex biomolecular sensing/recognition via SERS and SERRS.
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PMID:Silver-particle-based surface-enhanced resonance Raman scattering spectroscopy for biomolecular sensing and recognition. 1731 10

The infrared absorption, Raman spectra and SERS spectra of p-amino acetanilide have been analyzed with the aid of density functional theory calculations at B3LYP/6-311G(d,p) level. The electric dipole moment (mu) and the first hyperpolarizability (beta) values of the investigated molecule have been computed using ab initio quantum mechanical calculations. The calculation results also show that the synthesized molecule might have microscopic nonlinear optical (NLO) behavior with non-zero values. Computed geometries reveal that the PAA molecule is planar, while secondary amide group is twisted with respect to the phenyl ring is found, upon hydrogen bonding. The hyperconjugation of the C=O group with adjacent C-C bond and donor-acceptor interaction associated with the secondary amide have been investigated using computed geometry. The carbonyl stretching band position is found to be influenced by the tendency of phenyl ring to withdraw nitrogen lone pair, intermolecular hydrogen bonding, conjugation and hyperconjugation. The existence of intramolecular C=O...H hydrogen bonded have been investigated by means of the natural bonding orbital (NBO) analysis. The influence of the decrease of N-H and C=O bond orders and increase of C-N bond orders due to donor-acceptor interaction has been identified in the vibrational spectra. The SERS spectral analysis reveals that the large enhancement of in-plane bending, out of plane bending and ring breathing modes in the surface-enhanced Raman scattering spectrum indicates that the molecule is adsorbed on the silver surface in a 'atleast vertical' configuration, with the ring perpendicular to the silver surface.
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PMID:Molecular structure, spectroscopic studies and first-order molecular hyperpolarizabilities of p-amino acetanilide. 1832 71


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