Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Binding of a tetra peptide, lysyl tryptophenyl glycyl lysine O-ter butyl ester (KWGK) with duplex forms of G, C containing polynucleotides, Poly [d(G-C)], Poly [d(G-5M C)], Poly (dG), Poly (dC) and E.coli DNA were studied under low salt conditions using UV absorption, fluorescence, and circular dichroic (C.D) spectroscopy. On addition of the peptide (upto a P/N mole ratio of 0.5), the Poly [d(G-5M C)] under low salt (1 mM Na Cl) conditions, was converted from Z to B-form as shown by the inversion of C.D spectra. The two binding constants (K1 and K2) were determined from fluorescence spectroscopy of which K2 estimates the intercalation of the tryptophenyl side chain between the base pairs of DNA and K1 estimates the electrostatic interactions between the lysyl side chains and phosphate groups. The strength of intercalation is: Z-form of Poly [d(G-5M C)] >> B form of Poly [d(G-5M C)] >> E.Coli DNA > Poly (dG).Poly (dC). This means that peptide seems to have strong preference for Z compared to B-form and for alternating over non-alternating G, C Sequences. This suggests that tryptophan intercalation may act as a discriminating factor in recognizing Z and B-forms and may have a potential role in Protein-Nucleic acid interactions that are important for transcription.
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PMID:Tryptophan intercalation in G, C containing polynucleotides: Z to B conversion of poly [d(G-5M C)] in low salt induced by a tetra peptide. 887 59

Poly(methyl vinyl ether-alt-maleic anhydride) substituted with cholamine (CA), aminoethylcholamine (AECA), or aminooctylcholamine (AOCA) at different substitution degrees, were used for methotrexate (MTX) complexation. The solid complexes, isolated by precipitation from the preparative mixture, showed lower fractional releases at pH 7.4 than at 5.5. This was ascribed to the establishment of ionic interactions between the ionized carboxyls of both the polymer and the drug and the quaternary ammonium groups of the substituents (CA, AECA, AOCA) inducing polymer self-aggregation and thus complex stabilization. The fractional release in pH 7.4 decreases with the increase in the substitution degree until a minimum characteristic for each substituent analyzed is reached and then rises with the increase in substitution degree. The minimum release at pH 7.4 was observed in the presence of AECA at the degree of substitution corresponding to 0.35 mole of substituent per mole of dimer (methyl vinyl ethermaleic anhydride). None of the substituted polymers studied had any haemolytic effect, indicating good biocompatibility.
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PMID:Substituted poly(methyl vinyl ether-alt-maleic anhydride) for the release control and targeting of methotrexate. 988 Oct 57

Techniques of liver replacement would benefit patients awaiting donor livers and may be a substitute for transplantation in patients whose livers can regenerate. Poly(lactic-co-glycolic acid) (PLGA) copolymers are biodegradable and have been shown to be useful as scaffolds for seeding and culturing various types of cells. In this study, foam disks were prepared from PLGA (lactic-to-glycolic mole ratio of 85:15) by lyophilization of benzene (5% w/v) solutions. These disks were then used as scaffolds for rat hepatocyte culture. Foams were coated with either a type I collagen gel (0.1% w/v), coated with gelatin (5% w/v), or treated with oxygen plasma (25 W, 90 s) to modify their surface chemistry and wettability. The disks were then seeded with rat hepatocytes (10(6)/mL) and cultured for a period of 2 weeks. All surface treatments resulted in increased hydrophilicity, the greatest being obtained by collagen treatment (contact angle < 10 degrees ), and a minimal decrease in void fraction (5%). DNA content after a 2-week culture period increased proportionally with the wettability of the treated foam surface. Urea synthesis in untreated foams averaged 15.3 +/- 2.3 microg/h/microg DNA, which was significantly higher than that for controls, whereas gelatin and collagen treated foams exhibited urea synthetic rates below the control levels at all times. The DNA content decreased significantly by about 50% between days 1 and 12. PLGA foams, treated and untreated, represent a promising scaffold for scaling up hepatocyte cultures.
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PMID:Expression of liver-specific functions by rat hepatocytes seeded in treated poly(lactic-co-glycolic) acid biodegradable foams. 1150 28

Poly(L-histidine)-poly(ethylene glycol) diblock copolymers (polyHis-b-PEG) were prepared and used for the construction of polymeric micelles responding to local pH changes in the body. PolyHis was synthesized by ring opening polymerization of L-histidine N-carboxyanhydride, the imidazole amine group of which was protected by the dinitrophenyl group. The resulting polymer (M(n): 5,000 g/mole) was coupled to poly(ethylene glycol) (M(n): 2,000 g/mole) via an amide linkage using the dicyclohexyl carbodiimide and N-hydroxysuccinimide-mediated reaction. The block copolymer in dimethyl sulfoxide formed polymeric micelles on diafiltration against a borate buffer at pH 8. Dynamic light scattering and atomic force microscopy showed the micelles were spherical, diameter approximately 114 nm, with a unimodal distribution. The critical micelle concentration (CMC) at pH 8.0 was 2.3 mg/l. The CMC increased markedly on decreasing the pH of the diafiltration medium below 7.2. Micelles prepared at pH 8.0 were gradually destabilized below pH 7.4, as evidenced by a slight increase in light transmittance, an alteration in size distribution, and a decrease in the pyrene fluorescence intensity. It was concluded that the ionization of the polyHis block forming the micelle core determined the pH-dependent CMC and stability. After further optimization of the pH-sensitivity, pH-sensitive micelles are expected to have application for solid tumor treatment, exploiting the fact that most solid tumors have an acidic extracellular pH.
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PMID:Poly(L-histidine)-PEG block copolymer micelles and pH-induced destabilization. 1288 Jul 3

(Z)-3-[2H1]-Phenylprop-2-enone is isomerised by hydroperoxide to an equimolar mixture of the (Z)- and (E)-isomers prior to epoxidation. Poly-(L)-leucine (10 mole %) accelerates the addition of hydroperoxide by an order of magnitude and sequesters hydroperoxide from THF.
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PMID:The isomerisation of (Z)-3-[2H1]-phenylprop-2-enone as a measure of the rate of hydroperoxide addition in Weitz-Scheffer and Julia-Colonna epoxidations. 1536 53

Poly-aluminum-chloride-sulfate(PACS) with different SO4(2-)/Al3+ mole ratios and bacicity(y) of 2.0 was synthesized using AlCl3 x 6H2O, Al2 (SO4 )3 x 18H2O and Na2CO3 as raw materials. The effect of SO4(2-)/Al3+ ratio on the performance of PACS for removal of natural organic matter(NOM) with humic-rich actual water was examined. It was found that PACS with SO4(2-)/Al3+ mole ratio of 0.0664 achieved the best NOM removal results and was selected to investigate its performance in comparison with PAC, FeCl3 and alum (Al2 (SO4)3 x 18H2O). The experimental results showed that the optimum NOM removals were achieved at pH 5.0-8.2 and the dose of about 5.0 mg/L as Al both for the selected PACS and PAC, at pH 5.0-6.0 and the dose of about 7.0 mg/L as Fe for FeCl3, and at pH 5.0-7.0 and the dose of about 7.0 mg/L as Al for alum, respectively. At the optimum conditions, the selected PACS achieved the best NOM removal result, followed by PAC, FeCl3, and then alum. The concentration of residual aluminum in treated water by the selected PACS and PAC under the optimum coagulant conditions was approximately 115 microg/L, which can completely comply with the regulated limits.
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PMID:Natural organic matter (NOM) removal from surface water by coagulation. 1590 Jul 72

A simple approach to prepare and characterize biomaterial-based electrocatalysts for oxygen reduction was carried out. Poly-l-histidine was used as a matrix and ligand to complex Cu2+ to mimic the active sites of laccases. A modified glassy carbon (GC) electrode with Cu2+-poly-l-histidine complex decreases the oxygen reduction overpotential as compared with the bare GC electrode. An array of Cu2+-poly-l-histidine spots with different compositions was deposited on a GC substrate, and their catalytic activity for oxygen reduction was evaluated by a scanning electrochemical microscopy-based screening technique. The electrocatalytic activities of complexes for oxygen reduction strongly depended on the mole ratio of Cu2+ to poly-l-histidine and the applied potential of the substrate.
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PMID:Combinatorial biomimetics. optimization of a composition of copper(II) poly-L-histidine complex as an electrocatalyst for O2 reduction by scanning electrochemical microscopy. 1635 Oct 66

Poly(A)-RNA was purified from Nicotiana tabacum cell suspension cultures grown in the presence of N(6)-benzyladenine (BA). Cells were incubated with concentrations of 0.4 micromolar BA, optimal for cell division (OPT) or 10 micromolar BA, a cytostatic concentration (OVD), or without cytokinin (CTL) as a control. After 55 hours, total RNA was extracted from the cells and poly(A)-RNA was purified by oligo(dT)-cellulose binding. Similar yields of poly(A)-RNA were obtained for OPT or CTL cell samples; the compared recovery from the OVD cell samples was reduced by more than half. Poly(A)-RNA extracted from OPT or OVD cells contained BA nucleotide, inserted at the respective frequencies of 78 and 506 micromoles per mole conventional nucleotide. BA was inserted into the transcript as well as into the poly(A) segments. No qualitative or quantitative difference was observed between the in vitro translation activities of poly(A)-RNA extracted from OPT or CTL cells. The electrophoretic analysis of translation products from OVD mRNA showed a deficiency in proteins of molecular weight over 50 kilodaltons. This deficiency may be explained by a change in the coding properties of OVD mRNA rather than by a deficiency of the high molecular weight components in the mRNA population.
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PMID:Incorporation of N-Benzyladenine into Messenger Poly(A)-RNA of Tobacco Cells Incubated at Stimulatory or Cytostatic Cytokinin Concentration. 1666 79

Therapeutic strategies based on cell and tissue engineering can be advanced by developing material substrates that effectively interrogate the biological compartment, with or without the complimentary local release of growth factors. Poly(ether ester) segmented copolymers were engineered as model material systems to elucidate the interfacial molecular events that govern the function of adhered cells. Surface chemistry was modulated by varying poly(ethylene glycol) (PEG) length and mole fraction with poly(butylene terephthalate) (PBT), leading to differential competitive protein adsorption of fibronectin and vitronectin from serum and consequently to different cell attachment modes. Adhesion within the hydrogel-like milieu of longer surface PEG was mediated via binding to the CD44 transmembrane receptor, rather than the RGD-integrin mechanism, whereas greater substrate-bound fibronectin resulted in cell adhesion via integrins. These adhesion modalities differentially impacted morphological cell phenotype (spread or spheroid) and the subsequent expression of mRNA transcripts (collagen types II, I) characteristic of phenotypically differentiated or dedifferentiated chondrocytes, respectively. These results demonstrate that materials can be designed to directly elicit the membrane bound receptor apparatus desired for downstream cellular response, without requiring exogenous biological growth factors to enable differentiated potential.
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PMID:Modulation of chondrocyte phenotype for tissue engineering by designing the biologic-polymer carrier interface. 1709 26

Surface modification of colloidal silica with ferrocenyl-grafted polymer and colloidal crystallization of the particles in organic solvent were studied. Poly(methyl methacrylate-co-vinylferrocene)-grafted silica never formed colloidal crystals in polar solvent, such as acetone, acetonitrile, ethanol and N,N-dimethylformamide (DMF), while poly(methyl methacrylate-co-ferrocenyl acrylate)-grafted silica gave colloidal crystallization in DMF. The particles prepared by grafting of poly(N,N-dimethylacrylamide-co-vinylferrocene), with vinylferrocene (Vfc) mole fraction of 1/13 and 1/23, were observed to give the crystallization in ethanol and DMF over particle volume fraction of 0.058. Further, silica modified with copolymer of Vfc and N-vinyl-2-pyrrolidone, N-vinylcarbazole or N-isopropylacrylamide formed colloidal crystals in ethanol and DMF. Especially, poly(N-isopropylacrylamide-co-Vfc)-grafted silica, which was composed of the highest mole fraction of vinylferrocene, 1/3, afforded colloidal crystallization in ethanol over particle volume fraction of 0.053. Relatively high polar vinylferrocene copolymer grafting of silica resulted in colloidal polymerization in organic solvents.
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PMID:Colloidal crystallization of colloidal silica modified with ferrocenyl group-contained polymers in organic solvents. 1712 37


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