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 activity of the lithium ion against DNA type viruses is explained by its competition with magnesium ions. Magnesium acts as the cofactor of the enzymes responsible for the replicative building of viral proteins and nucleosides. When lithium replaces magnesium, it appears to render the polymerase enzymes impotent. Association constants for lithium and magnesium with ATP, a pertinent model substance, are of the same order of magnitude, which shows that interference must occur. Some chelating agents such as PAA have antiviral properties, and their action can be explained also if the delta G of their binding of magnesium is more negative than that of magnesium with ATP. This again displaces the magnesium as the enzymatic cofactor, thereby halting viral replication.
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PMID:Lithium and viruses. 361 10

Of the several existing methods for quantification of major subspecies of high density lipoprotein (HDL), HDL2 and HDL3, the methods based upon double precipitation are particularly useful for large-scale studies or for routine assay because of their high speed and low cost. The Vertical Auto Profile-II (VAP-II) method developed in our laboratory primarily for the direct single test measurement of cholesterol (C) in all major lipoproteins, including Lp[a] and IDL, is rapid, highly sensitive, and suitable for large-scale studies. Here we describe the modification of this procedure so as to be able to quantify both HDL2- and HDL3-C in addition to all major lipoproteins without any additional assay steps, time, or cost. The VAP-II procedure was validated by comparison with four other methods using plasma samples obtained from 35 healthy subjects: 1) HDL-VAP-II (a variation of the VAP-II procedure designed specifically to separate HDL subspecies); 2) dextran sulfate (DS)/Mg2+ double precipitation method performed at Northwest Lipid Research Laboratories (NWLRL), Seattle, WA; 3) 4-30% polyacrylamide-agarose (4/30 PAA) nondenaturing gradient gel electrophoresis (GGE); and 4) analytical ultracentrifugation (AUC), with both GGE and AUC performed at the Donner Laboratory, University of California at Berkeley. Both HDL2- and HDL3-C measurements by VAP-II correlated well with the measurements by all comparison methods (r for HDL3-C: HDL-VAP-II, 0.948; NWLRL, 0.947; GGE, 0.861; and AUC, 0.706, and r for HDL2-C: HDL-VAP-II, 0.867; NWLRL, 0.854; GGE, 0.885; and AUC, 0.721). The measurements of HDL2- and HDL3-C by the VAP-II method are reproducible, with the long-term between-rotor CV of 5.0% for HDL3-C and 9.0% for HDL2-C.
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PMID:Quantification of HDL2 and HDL3 cholesterol by the Vertical Auto Profile-II (VAP-II) methodology. 939 33

The static and time-resolved photoluminescence properties of polystyrene-b-poly(acrylic acid) (PS-b-PAA)-stabilized cadmium sulfide quantum dots (CdS QDs) have been characterized for the first time, demonstrating tunable emission spectra and quantum yields via different chemical treatments of the PAA layer. Samples with the PAA layer in its cadmium carboxylate form showed more-intense band-edge emission and relatively high quantum yields compared with samples in which the PAA layer was in its acid form. This activation effect is explained in terms of passivation of trap sites on the QD surface by specific interactions between the QD and the cadmium-neutralized PAA layer. Lifetimes of band-edge and trap state emission for the various samples ranged from 40 to 61 ns and 244 to 360 ns, respectively. Impressive long-term stability was also shown for a sample of cadmium-neutralized PS-b-PAA-stabilized QDs dispersed in toluene, which maintained 90% of its photoluminescence over 57 days aging under ambient conditions. It is also shown that Cd2+ activation of photoluminescence does not occur when Mg2+ ions are added to similar QD solutions, indicating potential of these block copolymer-stabilized QDs as Cd2+-selective sensors. Irrespective of chemical treatment of the PAA layer, the external PS brush layer effectively stabilized all samples in various organic solvents, resulting in clear CdS colloids with no observed precipitation over several months. Dynamic light scattering and gel permeation chromatography revealed differences in the aggregation numbers and hydrodynamic radii of colloidal QDs for different treatments of the PAA layer, attributed to the lower solubility of the poly(cadmium acrylate) blocks compared to the PAA blocks in the acid form. Finally, it was demonstrated that the PS-b-PAA-stabilized QDs could be well dispersed in PS homopolymer, producing optically transparent photoluminescent films which retained the emission features of the colloidal QDs. Stable and surface-tunable optical properties via the PAA layer and polymer solubility and processability via the PS layer make these PS-b-PAA-stabilized CdS QDs exciting "building blocks" for the bottom-up assembly of functional hierarchical materials for photonics, sensors, and bio-labeling applications.
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PMID:Surface-tunable photoluminescence from block copolymer-stabilized cadmium sulfide quantum dots. 1559 12

A new class of nano-scale Fe0 particles (NZVI) supported on a PAA/PVDF membrane (NZVI-PAA/PVDF) were synthesized and the feasibility of using NZVI-PAA/PVDF for reductive immobilization of Cr(VI) in water was investigated through laboratory batch tests. The results showed that the Cr(VI) removal capacity of NZVI-PAA/PVDF was 181 mg Cr/g Fe at an initial Cr(VI) concentration of 20 mg L(-1) under pH 6.5 +/- 0.1. XPS results showed that Cr(VI) was converted to nontoxic Cr(III). Interfering ions exerted various degrees of impact on NZVI-PAA/PVDF's Cr(VI) removal capacity. Specifically, Ca2+ alone showed the mildest impact while the presence of ions (Mg2+ and HCO3-) exerted the greatest impact. An advantage of NZVI-PAA/PVDF is that the nano-scale Fe0 and resultant particles were combined within a PAA/PVDF membrane, which prevents secondary pollution. Moreover, a piece of PAA/PVDF membrane (4.7 cm diameter) can still support 6.51 mg of nano-scale Fe0 particles after being renewed.
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PMID:Reduction and immobilization of chromium(VI) by nano-scale Fe0 particles supported on reproducible PAA/PVDF membrane. 2149 83