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

Aqueous solutions of poly(vinylphosphonic acid) have been found to form polyelectrolyte cements with a wide range of metal oxides. Poly(vinylphosphonic acid), PVPA, has a structure similar to that of poly(acrylic acid), PAA, but contains pendant phosphonic acid,--P(O)(OH)2, groups in place of the carboxylic acid,--COOH, groups of the zinc polycarboxylate, and glass polyalkenoate cements. It is a stronger acid than PAA, with a greatly increased reactivity toward metal oxides. The physical and mechanical properties of a number of metal oxide PVPA cements were studied and compared with those of zinc polycarboxylate cements. The faster acting of the metal oxide PVPA cement seems to produce a cement that is less susceptible to early hydrolysis.
 ...
PMID:The formation and properties of metal oxide poly(vinylphosphonic acid) cements. 152 97

The uptake characteristics of negatively-charged liposomes made by conjugation of poly(acrylic acid) (PAA) were studied with respect to cultured RAW macrophages. The PAA-conjugated liposomes were internalized and digested in an acidic compartment at a much faster rate than the unmodified phosphatidylcholine (PC) liposomes. After incubation for 18 h, an over 5-fold increase in the uptake of PC liposomes was obtained by PAA conjugation. Subsequently, part of the aqueous phase of the internalized liposomes was exocytosed. Recognition of PAA by the macrophages seems to be responsible for the enhanced uptake of PAA-conjugated liposomes. Cross-competition experiments showed that PAA-conjugated liposomes inhibited the uptake of acetylated-low density lipoprotein (acetyl-LDL) by the macrophages and vice versa. The uptake of PAA-conjugated liposomes was also inhibited by dextran sulfate and maleylated-bovine serum albumin (maleyl-BSA), which are also known to bind to scavenger receptors. Poly(C) and BSA, which are not ligands for the scavenger receptor, competed poorly with the uptake of PAA-conjugated liposomes. Enhanced uptake of PAA-conjugated liposomes by CHO cells with low scavenger receptor expression was not observed. Unexpectedly, LDL, which is not a ligand for scavenger receptor, also partially inhibited the uptake of PAA-conjugated liposomes. The interaction of PAA-conjugated liposomes with macrophages is complex, and the endocytosis of PAA-conjugated liposomes most likely involves multiple receptors and/or pathways. The data obtained suggest that the high affinity binding of PAA-conjugated liposomes to macrophages may be due to recognition of the negative charges of PAA by cell surface receptors, including the scavenger receptor.
 ...
PMID:Receptor-mediated endocytosis of poly(acrylic acid)-conjugated liposomes by macrophages. 861 8

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.
 ...
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

Poly(amidoamine)s (PAAs) are water-soluble polymers that display pH-dependent membrane activity. PAAs have the potential to act as a synthetic alternative to fusogenic peptides and thus promote endosomal escape. The purpose of this study was to investigate for the first time whether PAA have the ability to complex DNA, protect it from nuclease degradation and to promote transfection in vitro. PAAs ISA 1 (Mn 6900) and ISA 23 (Mn 10,500) and their 2-phenylethylamine containing analogues ISA 4 and ISA 22 (Mn approximately 8000) were studied. All PAAs retarded the electrophoretic mobility of lambda Hind III DNA demonstrating interpolyelectrolyte complex (IPEC) formation and toroids of 80-150 nm in diameter (10:1 polymer excess) were visible using TEM. DNase II inhibition was observed. At a polymer:DNA ratio of 10:1, this was ISA 1(89.6 +/- 6.1%), ISA 4 (92.2 +/- 11.2%), ISA 22 (69.4 +/- 3.7%), and ISA 23 (58.0 +/- 10.0%). PAAs demonstrated the ability to mediate pSV beta-galactosidase transfection of HepG2 cells. At a vector:DNA mass ratio of 5:1, ISA 23 showed equivalent transfection ability compared with polyethylenimine and LipofectIN and was more effective than LipofectACE. These properties suggest that PAAs warrant further development as endosomolytic vectors.
 ...
PMID:Poly(amidoamine)s as potential nonviral vectors: ability to form interpolyelectrolyte complexes and to mediate transfection in vitro. 1171 5

Poly(amidoamine)s (PAAs) are water-soluble synthetic polymers designed to be biodegradable and biocompatible. Moreover, they display membrane disruptive properties in response to a decrease in pH. This attribute confers PAAs with endosomolytic properties in vitro and in vivo. A model system was developed to quantify their ability to promote the endosomal escape of macromolecules that may be interesting as therapeutic agents. Here, two PAAs (ISA 1 and 4) were incubated with B16F10 cells in vitro together with two non-permeant toxins: either ricin A-chain (RTA) or gelonin. The relatively non-toxic PAAs ISA 1 and 4 (IC50>1.5 mg/ml) restored activity to the inherently inert toxins. The IC50 values for the ISA 1/RTA and ISA 1/gelonin combinations were 0.65+/-0.05 and 0.55+/-0.12 mg/ml, respectively. Similarly, when ISA 4 was incubated with a non-toxic combination of RTA and gelonin the IC50 value decreased to 0.57+/-0.03 and 0.43+/-0.26 mg/ml, respectively. In contrast, the neutral polymer dextran and the PAA ISA 22 were unable to mediate this effect. These observations suggest that specific PAA-toxin combinations warrant further development as novel therapeutics.
 ...
PMID:Poly(amidoamine)-mediated intracytoplasmic delivery of ricin A-chain and gelonin. 1173 90

Poly(aspartic acid) (PAA) hydrolase was purified from Sphingomonas sp. KT-1 (JCM10459). The purified hydrolase degraded thermally synthesized PAA to oligomers. The molecular mass of PAA hydrolase was 30 kDa and the isoelectric point was 8.9. The optimum values of pH and temperature for PAA degradation were 10.0 and 40 degrees C, respectively. The investigation of the effect of inhibitors for the PAA-degrading activities has revealed that the PAA hydrolase is a serine-type hydrolase. The structural analysis of PAA-degraded products using (1)H and (13)C nuclear magnetic resonances has indicated that the purified enzyme hydrolyzes selectively the beta-amide linkage connecting with beta-aspartic acid units in PAA.
 ...
PMID:Purification and characterization of poly(aspartic acid) hydrolase from Sphingomonas sp. KT-1. 1177 87

A surface plasmon resonance (SPR) sensor was applied to analyses of some amine compounds (n-butylamine, isobutylamine, aniline, and N,N-dimethylaniline) by using a polymer film and an acid-base reaction in it. Poly(acrylamide) (PAA) was adopted as the polymer film and was immobilized on an Au film to prepare a sensor chip. Pivalic acid was entered into the PAA film as an acid. The PAA film with a thickness of 50 nm gave the highest sensitivity to the SPR sensor. Although water was better concerning the sensitivity for the SPR sensor as the solvent, ethanol was adopted because it dissolves well all of the amine compounds used. The Au film coated with the PAA film gave higher sensitivity for analyses of n-butylamine and isobutylamine, and lower sensitivity for analyses of aniline and N,N-dimethylaniline than an Au film without the PAA film. The PAA film containing pivalic acid gave 4-5 orders of magnitude higher sensitivity to the SPR sensor for analyses of all the amine compounds due to the reaction between pivalic acid and these amine compounds.
 ...
PMID:Application of a surface plasmon resonance sensor to analyses of amine compounds with the use of a polymer film and an acid-base reaction. 1191 82

Poly(aspartic acid) (PAA) hydrolase-2 was purified from crude soluble cellular extracts of Sphingomonas sp. KT-1 (JCM10459) and characterized to elucidate the mechanism of alpha,beta-poly(d,l-aspartic acid) (tPAA) biodegradation. The molecular mass of PAA hydrolase-2 was 42 kDa, and the isoelectric point was 9.6. The optimum values of pH and temperature for the hydrolysis of alpha-di(l-aspartic acid) by PAA hydrolase-2 were 7.0 and 55 degrees C, respectively. The effect of inhibitors on the hydrolysis of alpha-di(l-aspartic acid) showed that the activity of PAA hydrolase-2 was significantly inhibited by EDTA. Thermally synthesized tPAA was hydrolyzed in the presence of two enzymes, PAA hydrolase-1 and PAA hydrolase-2, to generate aspartic acid. The PAA hydrolase-2 was capable of hydrolyzing alpha-poly(l-aspartic acid) of high molecular weights but had limited activity for tPAA. These results lead us to propose the following mechanism. First, PAA hydrolase-1 hydrolyzes tPAA to yield oligo(aspartic acid) via an endo-mode cleavage, and subsequently, PAA hydrolase-2 hydrolyzes the resultant oligo(aspartic acid) to yield aspartic acid. Analysis of hydrolyzed products from alpha- and beta-penta(l-aspartic acid) revealed that PAA hydrolase-2 catalyzed the exo-mode hydrolysis of alpha- and beta-penta (l-aspartic acid). The gene encoding PAA hydrolase-2 from Sphingomonas sp. KT-1 was cloned, and genetic analysis showed that the deduced amino acid sequence of PAA hydrolase-2 is similar to a putative peptidase, which belongs to the M20/M25/M40 family of proteins, from Caulobacter crescentus CB15.
 ...
PMID:Biochemical and molecular characterization of poly(aspartic acid) hydrolase-2 from sphingomonas sp. KT-1. 1295 96

Oral induction of a disseminated mucosal immune response with polyplex-based DNA vaccines requires the delivery of intact polyplexes (polyelectrolyte complexes formed by self-assembly of plasmid DNA with a cationic polymer) to subepithelial lymphoid tissue (e.g. Peyer's patches) within the gastrointestinal tract. This work describes the formulation of a microparticle polyplex carrier allowing the potential of this approach to be realised. PEGylated PEI/DNA polyplexes (DNA concentration 20 microg/ml) formed at N/P 5:0 (defined as the ratio of polycation amino groups to DNA phosphates) were stable to salt-induced aggregation and could be concentrated to a final DNA concentration of 1 mg/ml without polyplex size increase. Polyplexes containing 1:1 polyethylene glycol (PEG)/polyethylenimine (PEI) ratio (mass/mass) gave similar levels of luciferase gene expression in B16F10 cells compared to non-PEG complexes. Poly-(D,L-lactide-co-glycolide) (PLGA) microparticles containing PEGylated polyplexes (approximately 17% DNA encapsulation efficiency) were formulated using a modified double emulsion solvent evaporation method. The microencapsulation and release of intact polyplexes from the microparticle carrier was demonstrated using polyanion (heparin sulfate and poly(aspartic acid) (PAA)) displacement techniques and electron microscopy. Microparticles containing PEGylated polyplexes (24 microg beta-galactosidase DNA) were given orally to Wistar rats. Significant transgene expression (compared to background) was found in peripheral tissue (spleen) 72 h after administration. This work demonstrates the potential application of microparticle carriers for mucosal polyplex-based vaccination.
 ...
PMID:Formulation of a microparticle carrier for oral polyplex-based DNA vaccines. 1537 19

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.
 ...
PMID:Creating effective refractive index gradients within polyelectrolyte multilayer films: molecularly assembled rugate filters. 1587 62


1 2 3 4 5 6 7 8 9 10 Next >>