Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30536 (PBS)
 9,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The potential of a mucoadhesive polymer as an ophthalmic vehicle is evaluated within the rabbit. Precorneal clearance of a mucoadhesive polymer solution (Carbopol 934P) is compared to that of an equiviscous nonmucoadhesive poly(vinyl alcohol) solution (PVA) and buffer (PBS). The precorneal retention of the Carbopol 934P, as studied by lacrimal dacryoscintigraphy, is shown to be significantly greater (P less than 0.05) than that of PVA, which, in turn, is significantly greater than that of PBS. The effect of the polymer solution on the bioavailability of pilocarpine is subsequently assessed by measuring the relative miotic response intensities produced by a 1% solution of the drug. Carbopol 934P solution produces a significant increase (P less than 0.05) in bioavailability as compared to PVA and PBS. The bioavailability from PVA is significantly greater (P less than 0.05) than that from PBS. Studies evaluating vehicle-drug association indicated no binding of the drug to the polymer.
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PMID:Evaluation of mucoadhesive polymers in ocular drug delivery. I. Viscous solutions. 192 57

The entrapment of lysozyme in amphiphilic multiblock copolymer microspheres by emulsification and subsequent solvent removal processes was studied. The copolymers are composed of hydrophilic poly(ethylene glycol) (PEG) blocks and hydrophobic poly(butylene terephthalate) (PBT) blocks. Direct solvent extraction from a water-in-oil (w/o) emulsion in ethanol or methanol did not result in the formation of microspheres, due to massive polymer precipitation caused by rapid solvent extraction in these non-solvents. In a second process, microspheres were first prepared by a water-in-oil-in-water (w/o/w) emulsion system with 4% poly(vinyl alcohol) (PVA) as stabilizer in the external phase, followed by extraction of the remaining solvent. As non-solvents ethanol, methanol and mixtures of methanol and water were employed. However, the use of alcohols in the extraction medium resulted in microspheres which gave an incomplete lysozyme release at a non-constant rate. Complete lysozyme release was obtained from microspheres prepared by an emulsification-solvent evaporation method in PBS containing poly(vinyl pyrrolidone) (PVP) or PVA as stabilizer. PVA was most effective in stabilizing the w/o/w emulsion. Perfectly spherical microspheres were produced, with high protein entrapment efficiencies. These microspheres released lysozyme at an almost constant rate for approximately 28 days. The reproducibility of the w/o/w emulsion process was demonstrated by comparing particle characteristics and release profiles of three batches, prepared under similar conditions.
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PMID:Microspheres for protein delivery prepared from amphiphilic multiblock copolymers. 1. Influence of preparation techniques on particle characteristics and protein delivery. 1082 57

Poly(propylene fumarate-co-ethylene glycol) random (PPF-1) and block (PPF-2) copolymer oligomers were prepared. Comparing the setting characteristics of PPF-1 and PPF-2 with comonomer n-vinyl pyrrolidone (n-VP) and swelling characteristics of cured PPF-1 and PPF-2, lower setting temperature and setting time was observed with the former leading to higher swelling coefficient and lower cross link density in the cured PPF-1. Due to the high swelling coefficient and low setting exothermic temperature associated with PPF-1, the bone cement was prepared from PPF-1, n-VP and hydroxyapatite (HAP). The in vitro degradation studies reveal lesser weight loss and deformation of PPF-1/n-VP/HAP based cured resin in Ringer's solution and phosphate buffered saline in comparison with that of PPF-1/n-VP cured resin. Though the bone cement composite has adequate mechanical properties with HAP, the compressive strength and modulus of the composite aged in Ringer's solution and PBS reduced appreciably which is due to extensive hydration and plasticization by the PEG unit. However, the bone-binding and bond strength of the bone cement determined as the load for separation of bones was found to be similar to that of fast setting calcium phosphate-atelocollagen (5%) bone cement. The bone cement PPF-1/n-VP/HAP could be used as scaffold for correcting the bone defects.
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PMID:Studies on poly(propylene fumarate-co-ethylene glycol) based bone cement. 1108 40

O(2) was electroreduced to water at 0.6 V (SHE) near neutral pH on the "wired" Pleurotus ostreatus laccase cathode. We previously reported high-current density (5 mA cm(-2)), four-electron electroreduction of O(2) to water on a "wired" Coriolus hirsutus laccase electrode at +0.7 V (SHE) in pH 5 in citrate buffer. Since the enzyme was inhibited by chloride and because its activity declined steeply when the pH was raised to neutral, the rate of O(2) electroreduction in a physiological buffer solution was only approximately 1% of that at pH 5 in absence of chloride. Here we show that substitution of the C. hirsutus laccase by laccase from P. ostreatus allows the upward extension of the pH range of O(2) electroreduction. The current density of the electrode made with laccase from P. ostreatus in pH 7 citrate buffer was approximately 100 microA cm(-2) and at pH 7 and in phosphate buffered NaCl (PBS, 20 mM phosphate, 0.1 M NaCl) it still retained 6% of its maximal (1 mA cm(-2)) current density at pH 5 in citrate buffer. The electrocatalyst consisted of the crosslinked P. ostreatus laccase and the electron conducting redox polymer PVI-Os(dmebpy)(tpy)(2+/3+) [PVI=poly(N-vinyl imidazole) with about 1/5th of the rings complexed with (Os-dmebpy-tpy)(2+/3+); dmebpy=4,4'-dimethyl-2,2'-bipyridine; tpy=2,2',6',2"-terpyridine].
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PMID:Electroreduction of O(2) to water at 0.6 V (SHE) at pH 7 on the "wired" Pleurotus ostreatus laccase cathode. 1239 57

Ultrasonically induced cell damage and active oxygen generation with 4-formyloximeetylidene-3-hydroxyl-2-vinyl-deuterio-porphynyl(IX)-6-7-diaspartic acid (ATX-S10) were compared in the same in vitro insonation setup. Sarcoma 180 cells suspended in air-saturated PBS were exposed to ultrasound at 2 MHz for up to 60 s in the presence and absence of ATX-S10. The viability was determined by Trypan blue exclusion test. Ultrasonically induced active oxygen generation in the presence and absence of ATX-S10 in air-saturated aqueous solutions of 50 mM 2,2,6,6-tetramethyl-4-piperidone was detected by electron spin resonance (ESR). Significant enhancement of the rates of both ultrasonically induced cell damage and nitroxide generation was demonstrated with 40-160 microM ATX-S10. Both rates correlated very well. The enhancement of both rates with ATX-S10 was suppressed by 10 mM histidine. These results suggest that ultrasonically generated active oxygen plays a primary role in the ultrasonically induced cell damage in the presence of ATX-S10.
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PMID:Ultrasonically induced cell damage and active oxygen generation by 4-formyloximeetylidene-3-hydroxyl-2-vinyl-deuterio-porphynyl(IX)-6-7-diaspartic acid: on the mechanism of sonodynamic activation. 1259 87

Layer-by-layer deposited anticoagulant multilayer films were prepared on ammonia plasma treated poly (vinyl chloride) (PVC). Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and contact angle results revealed the presence of -NH2 on the ammonia plasma treated PVC surfaces and the layer-by-layer self-assembly process. The stability of multilayer film was studied with the radio labeled method. The remainder bovine serum albumin (BSA) in cross-linked 5(heparin/BSA) multilayer films dipped in phosphate buffered saline (PBS, pH 7.4) was more than 90% in 40 days. The static platelet adhesion result indicated the anticoagulant multilayer films deposited on the plasma treated PVC reduced platelet adhesion drastically and no thrombus forming. The plasma recalcification time revealed that the multilayer modified surfaces greatly prolonged the plasma recalcification time. Such an easy processing and shape-independent method may have good potential for surface modification of cardiovascular devices.
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PMID:Fabrication of thromboresistant multilayer thin film on plasma treated poly (vinyl chloride) surface. 1596 2

DNA nano-carriers were formulated relying on biodegradable polyesters consisting of amine-modified poly(vinyl alcohol) (PVAL) backbones grafted with PLGA, based on the Marangoni effect thus avoiding detrimental shear or ultrasonic forces. These amine modified high molecular weight biodegradable polyesters combine specific characteristics, such as electrostatic interactions between DNA and cationic branched polyesters facilitating loading of NP with DNA. The resulting DNA containing NP showed hydrodynamic diameters in the range of 175-285 nm and highly positive xi-potentials, depending on the nitrogen to phosphate (N/P) ratio used for the particle formation. Atomic force microscopy (AFM) demonstrated well-defined spherical particle morphologies. DNA was released from NP upon incubation in PBS buffer in its intact supercoiled form. Agarose gel electrophoresis demonstrated that DNA within the NP was protected from enzyme degradation. The biological efficiency of the DNA delivery by this nano-carrier was demonstrated by an in vitro transfection assay using four cell lines. Reporter gene delivery of the amine-modified polymers was higher than naked DNA (Control) and raised with increasing degree of amine substitution. Also type of amine and distance of cationic charge from the backbone play an important role. Further, this feature was shown by Luciferase expression of the pCMV-Luc plasmid with PEI 25 kDa/DNA polyplexes and NP prepared with amine modified polyesters with a grafted PLGA chain length of 10 monomers compared at equal N/P ratios. DNA loaded NP from P(68)-10 showed 8x higher transfection efficiencies than the PEI 25 kDa at an N/P ratio of 9 for both preparations. These novel DNA nano-carriers merit further investigations in particular for DNA vaccination under in vivo conditions.
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PMID:DNA nano-carriers from biodegradable cationic branched polyesters are formed by a modified solvent displacement method. 1649 88

Lipase catalysis was successfully employed to synthesize high molecular weight poly(butylene succinate) (PBS). Attempts to copolymerize succinic acid with 1,4-butanediol were unsuccessful due to phase separation of the reactants. To circumvent this problem, monophasic reaction mixtures were prepared from diethyl succinate and 1,4-butanediol. The reactions were studied in bulk as well as in solution. Of the organic solvents evaluated, diphenyl ether was preferred, giving higher molecular weight products. After 24 h in diphenyl ether, polymerizations at 60, 70, 80, and 90 degrees C yielded PBS with M(n) of 2000, 4000, 8000, and 7000, respectively. Further increase in reaction time to 72 h resulted in little or no further increase in M(n). However, increasing the reaction time produced PBS with extraordinarily low M(w)/M(n) due to the diffusion and reaction between low-molecular weight oligomers and chains that occurs at a greater frequency than interchain transesterification. Time-course studies and visual observation of polymerizations at 80 degrees C revealed PBS precipitates at 5 to 10 h, limiting the growth of chains. To maintain a monophasic reaction mixture, the polymerization temperature was increased from 80 to 95 degrees C after 21 h. The result was an increase in the PBS molecular weight to M(w) = 38 000 (M(w)/M(n) = 1.39). This work paves the way for the synthesis of PBS macromers and polymers that contain variable quantities of monomers with chemically sensitive moieties (e.g., silicone, epoxy, vinyl). Furthermore, this study established the feasibility of using lipase catalysis to prepare polyesters from alpha,omega-linear aliphatic diethyl ester/diol monomers with less than six carbons.
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PMID:Candida antarctica lipase B-catalyzed synthesis of poly(butylene succinate): shorter chain building blocks also work. 1709 36

Nanofibrious composite poly(lactide-co-glycolide) (PLGA) and chitosan/poly(vinyl alcohol) (PVA) membranes were prepared by simultaneously electrospinning PLGA and chitosan/PVA from two different syringes. The in vitro degradation of PLGA and cross-linked composite membranes was examined for up to 10 weeks in phosphate-buffered saline (PBS, pH 7.4) at 37 degrees C. The pH of PBS, the weight average molecular weight of PLGA, fiber morphology and mechanical properties, including tensile strength, Young's modulus and elongation-at-break, were measured as a function of degradation time. The fibrous composite membranes were further investigated as a promising scaffold for human embryo skin fibroblasts (hESFs) culture. The cell adhesion and morphology of hESFs seeded on each electrospun membrane was observed using scanning electron microscope and inverted phase contrast microscopy after Wright-Giemsa staining. The introduction of chitosan/PVA component changed the hydrophilic/hydrophobic balance and, thus, influenced degradation behavior and mechanical properties of the composite membranes during degradation. The cells could not only favorably attach and grow well on the composite membranes, but were also able to migrate and infiltrate the membranes. Therefore, the results suggest that the composite membranes can positively mimic the structure of natural extracellular matrices and have the potential for application as three-dimensional tissue-engineering scaffolds.
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PMID:Degradation of electrospun PLGA-chitosan/PVA membranes and their cytocompatibility in vitro. 1727 54

The influence of the composition of the polymer coated polyvinyl alcohol (PVA), vinyl alcohol/vinyl amine copolymer (A-PVA) and polyethylenimine (PEI) coated superparamagnetic iron oxide nanoparticles (SPIONs) on the colloidal stability, cytotoxicity and cellular uptake of these particles in different cell media is reported in this paper. Although all examined polymer coated SPIONs were stable in water and PBS buffer these colloidal systems had different stabilities in DMEM or RPMI media without and supplemented with fetal calf serum (FCS). We found that A-PVA coating onto the surface of the SPIONs decreased the cytotoxicity of the polymer compared to the same concentration of A-PVA alone. As well, polyplexes of PEI-SPIONs with DNA in concentration used for transfection experiments showed no cytotoxicity compared to PEI and PEI-SPIONs. Our data show that the choice of medium largely influences the uptake of these particles by HeLa cells. The optimal medium is different for the different examined polymer coated SPIONs and it should be determined in each case, individually.
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PMID:Effect of cell media on polymer coated superparamagnetic iron oxide nanoparticles (SPIONs): colloidal stability, cytotoxicity, and cellular uptake studies. 1788 Dec 3


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