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)

ABA-type block copolymers (abbreviated as LEL) composed of poly(L-leucine) (PLL) as the A component and poly(ethylene glycol) (PEG) as the B component were synthesized by ring-opening polymerization of L-leucine N-carboxyanhydride initiated by primary amino group located at both ends of PEG chain. A silver sulfadiazine (AgSD)-impregnated wound dressing of sponge type was prepared by the lyophilization method. Morphological structure of this wound dressing by scanning electron microscopy was observed to be composed of a dense skin layer and a porous inner layer. Equilibrium water content of LEL wound dressing increased with an increase in PEG content in the block copolymer due to the hydrophilicity of PEG. AgSD release from AgSD-impregnated wound dressing in PBS buffer (pH = 7.4) was dependent on PEG content in the block copolymer. Release of AgSD was increased in proportion to the PEG content in the copolymer. Antibacterial capacity of AgSD-impregnated wound dressing was examined in agar plate against Pseudomonas aeruginosa and Staphylococcus aureus. It was found that the suppression of bacterial proliferation in the wound dressing was dependent upon the PEG content. In cytotoxicity test, cell damage did not occur by the release of AgSD from the LEL sponge matrix of AgSD-medicated wound dressing. In in vivo test, granulous tissue formation and wound contraction for the AgSD- and dehydroepiandrosterone-impregnated LEL-2 wound dressing were faster than for any other groups.
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PMID:Possibility of wound dressing using poly(L-leucine)/poly(ethylene glycol)/poly(L-leucine) triblock copolymer. 1063 95

One of the major problems raised by the microencapsulation of drugs which are sparingly soluble in water is the difficulty to achieve a controlled and total release of the drug. It was previously shown that the microencapsulation of a model water insoluble drug, namely 1-[2-(4-fluorobenzoyl)aminoethyl]-4-(7-methoxynaphthyl) piperazine hydrochloride (FAMP) with a hydrophilic additive like low molar mass poly(ethylene glycol)s (PEG) can fulfil these requirements, provided all the drug + additive matter is in contact with the surrounding liquid medium via open pores and percolating channels. In this paper, PEG was replaced by other additives, selected because of their potential ability to increase the solubility of FAMP in pH = 7.4 isosomolar phosphate buffer (PBS). The idea was that increasing the solubility locally in microparticles could allow the drug to be released, despite its poor solubility in aqueous media like body fluids, and be absorbed before recrystallization. The solubility in PBS of FAMP mixed with additive, in the form of solid dispersions, was determined for various additives, namely citric acid, dimyristoyl DL-alpha-phosphatidyl choline (DMPC), poloxamer copolymers of different compositions and poly(dodecyl L-lysine citramidate) (PLCAC12(100)), an aggregate-forming hydrophilic polyelectrolyte containing 100%, hydrophobizing ester groups which can accommodate lipophilic compounds in hydrophobic pockets present in the aggregates. PEG was taken as a reference. It was found that DMPC, some poloxamers and the hydrophobized polyelectrolyte do increase the solubility of FAMP in PBS. Investigation was made of the release of FAMP from ground microparticles, whose loads were composed of FAMP combined with these solubilization-promoting additives. It was found that the release rate of FAMP from such systems can be increased and modulated to achieve an in vitro sustained release over a 20-30 day period and secure exhaustion of the particles at the end of this period.
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PMID:The use of additives to modulate the release of a sparingly water soluble drug entrapped in PLA50 microparticles. 1067 Sep 42

The objective of this study was to improve the survival of in vitro-produced bovine morulae after cry opreservation. In Experiment 1, presumptive zygotes at 20 h post-insemination (hpi) were cultured in a mixture of modified synthetic oviduct fluid (m-SOF)/0.3% BSA and m-SOF/0.3% linoleic acid-albumin from bovine serum (LAA) at 39.0 degrees C in 5% O2, 5% CO2 and 90% N2 (final LAA concentration: 0, 0.01, 0.03, 0.1 or 0.3%). Morulae harvested at 138 hpi were frozen and thawed in m-PBS/0.3% BSA containing 1.5 M ethylene glycol and were cultured for 96 h in m-SOF/10% FBS to assess further development. The post-thaw survival of morulae derived from culture in 0.1% LAA (60%, P < 0.01) and in 0.03% LAA (55%, P < 0.05) was higher than that in 0% LAA (32%). Lowering the LAA concentration below 0.1% resulted in similar rates of morula development as in m-SOF/0.3% BSA. In Experiment 2, zygotes were cultured in m-SOF/0.1% LAA from 20 to 90 hpi and/or from 90 to 138 hpi. Post-thaw survival of morulae that had been exposed to LAA from 20 to 90 hpi (39%) or from 90 to 138 hpi (56%) was higher than that of morulae cultured without LAA from 20 to 138 hpi (12%, P < 0.02). These survival rates were lower than that of morulae cultured with LAA over a period of 20 to 138 hpi (76%, P < 0.001). The results indicate that cell-free culture of IVM/IVF bovine zygotes in m-SOF supplemented with LAA produces morula-stage embryos relatively tolerant to the process of freezing and thawing.
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PMID:Effect of linoleic acid-albumin in the culture medium on freezing sensitivity of in vitro-produced bovine morulae. 1073 83

The recently introduced Open Pulled Straw (OPS) vitrification technique has successfully been used for cryopreserving porcine embryos as well as for bovine embryos and oocytes. The aim of this work is to investigate several factors on the in vitro survival of bovine blastocysts. In 5 experiments, a total of 862 in vitro produced blastocysts and expanded blastocysts was vitrified and warmed using the OPS technology, then cultured in vitro for an additional 3 days. The culture medium in Experiments 1 to 4 was SOFaa with supplements and 5% calf serum (CS). In Experiment 1, the replacement of TCM-199 + 20% CS with PBS + 20% CS in the holding medium during vitrification and warming did not result in significant differences in the re-expansion (92 vs 95%) and hatching rates (79 vs 72%). In Experiment 2, the PBS holding medium was supplemented with either 20% CS, 5 mg/mL bovine serum albumin (BSA) or 3 mg/mL polyvinylalcohol (PVA). Although the re-expansion rates did not differ (98, 95 and 93%, respectively), there was a decrease in the hatching rate after vitrification with PVA (77 and 78 vs 51%, respectively). In Experiment 3, the influence of temperature of equilibration media prior to and rehydration media after the vitrification was investigated. When the temperature of these media was adjusted to 20 degrees C instead of the standard 35 degrees C, both the re-expansion and the hatching rates decreased markedly. However, increasing the time of equilibration with the diluted cryoprotectant solution at 20 degrees C eliminated these differences. In Experiment 4, the ethylene-glycol and dimethyl sulfoxide cryoprotectant mixture was replaced with ethylene glycol-ficoll-trehalose solution. No difference in the re-expansion (89 vs 96%, respectively) or hatching rate (79 vs 84%, respectively) was detected. In Experiment 5, the vitrified-warmed blastocysts were cultured in SOFaa medium supplemented with 5% CS or 5 mg/mL BSA. Although the re-expansion rates were identical in the 2 groups (95%), the hatching rates were lower when embryos were cultured in BSA (71 and 47%, respectively). These findings indicated the possible broader application for OPS, as they demonstrated that the physical advantages of rapid cooling and warming may be accompanied by different chemical composition (holding media, cryoprotective additives) according to the requirements of the biological structure. Our study also shows the need for serum supplementation of the medium for hatching to occur after OPS vitrification.
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PMID:The effect of media, serum and temperature on in vitro survival of bovine blastocysts after Open Pulled Straw (OPS) vitrification. 1073 32

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

Ovine blastocysts were produced by maturation, fertilization and in vitro culture (IVM/IVF/IVC) of oocytes from slaughtered adult and prepubertal ewes and collection from superovulated and inseminated adult animals. Dulbecco's PBS supplemented with 0.3 mM Na Pyruvate and 20% FCS was used as the basic cryopreservation solution. The embryos were exposed to the vitrification solution as follows: 10% glycerol (G) for 5 min, then 10% G +20% ethylene glycol (EG) for 5 min. Embryos were placed into 25% G + 25% EG in the center of 0.25- mL straws and plunged immediately into LN2. Warming was done by placing the straws into a water bath at 37 degrees C for 20 sec, and their contents were expelled into a 0.5 M sucrose solution for 3 min; the embryos were then transferred into 0.25 M and 0.125 M sucrose solution for 3 min each. Warmed blastocysts were transferred to the culture medium for 24 h. Survival was defined as the re-expansion of the blastocoele. All surviving blastocysts were transferred to synchronized recipient ewes, and the pregnancy was allowed to go to term. Of 68 vitrified in vitro produced blastocysts, 46 re-expanded (67.6%) and 10 lambs were born (14.7%). From the 62 in vivo derived and vitrified embryos, 52 re-expanded (83.8%) and 39 lambs were born (62.9%). The lambing rate of in vitro produced fresh transfer embryos was 40% (20 lambs/50 blastocysts transferred), and of the 32 in vivo derived blastocysts and transferred fresh, 26 lambs were born (81.2%). The results indicate that in vitro produced embryos can be successfully cryopreserved by vitrification.
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PMID:Survival and viability of vitrified in vitro and in vivo produced ovine blastocysts. 1088 39

Preservation by vitrification of Day 7 and Day 8 bovine blastocysts derived from nuclear transfer with cumulus cells was compared with preservation of in vitro fertilized blastocysts. In Experiment 1, embryos were vitrified in PBS containing 60% ethylene glycol. In Experiment 2, they were vitrified in combination with partial dehydration using a solution of 39% ethylene glycol + 0.7 M sucrose and 8.6% Ficoll. In Experiment 1, survival and hatching rates were 44 and 95% for nuclear transferred embryos, and 78 and 55% for in vitro fertilized embryos, respectively. In Experiment 2, survival and hatching rates were 93 and 95% for nuclear transfer embryos, and 77 and 85% for in vitro fertilized embryos, respectively. It is concluded that Day 7 and Day 8 bovine blastocysts derived from cumulus cells could be cryopreserved without the loss of viability by a simple and efficient method using a combination of partial dehydration and vitrification.
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PMID:Efficient cryopreservation of bovine blastocysts derived from nuclear transfer with somatic cells using partial dehydration and vitrification. 1089 13

Biodegradable hydrogel nanoparticles were prepared from glycidyl methacrylate dextran (GMD) and dimethacrylate poly(ethylene glycol) (DMP). GMD was synthesized by coupling of glycidyl methacrylate to dextran in the presence of 4-(N,N-dimethylamino)pyridine (DMAP) using dimethylsulfoxide (DMSO) as an aprotic solvent. DMP was synthesized from poly(ethylene glycol) (PEG) and methacryloyl chloride. GMD/DMP (abbreviated as DP) hydrogel was prepared by radical polymerization of GMD and DMP using ammonium peroxydisulfate (APS) as an initiator and UV curing. DP hydrogel nanoparticles were obtained by diafiltration method using DMSO solution. The GMD and DMP were characterized by fourier transform infrared spectroscopy. Fluorescence probe technique was used to investigate the self-assembly of DP in water using pyrene as a hydrophobic probe. The critical association concentration (CAC) was determined to be 5.6 x 10(-2) g/l. The shape of DP hydrogel nanoparticles was spherical when observed by transmission electron microscope (TEM). The size range of DP hydrogel nanoparticles was about 20 approximately 50 nm. The hydrodynamic size of DP hydrogel nanoparticles was measured by photon correlation spectroscopy (PCS) and gradually increased with time in PBS (0.1 M, pH 7.4). Drug release study was performed using clonazepam (CNZ) as a hydrophobic model drug. In vitro release rate of CNZ from the DP hydrogel nanoparticles was dependent on the existence of dextranase and the pH of the release medium.
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PMID:Self-assembled hydrogel nanoparticles composed of dextran and poly(ethylene glycol) macromer. 1100 May 47

Morulae and unhatched blastocysts from Large White hyperprolific (LWh) and Meishan (MS) gilts were selected to test an ultrarapid open pulled straw (OPS) vitrification method with two media. The viability of vitrified/warmed embryos was estimated by the percentage of embryos that developed to the hatched blastocyst stage in vitro or by birth after transfer. In Experiment 1, two cryoprotectant dilution media were compared for cryopreservation of MS and LWh blastocysts: TCM was a standard Hepes-buffered TCM199 + 20% NBCS medium and PBS was a PBS + 20% NBCS medium. After a two-step equilibration in ethylene glycol, dimethyl sulfoxide, and sucrose, 2-5 blastocysts were loaded into OPS and plunged into liquid nitrogen. Embryos were warmed; a four-step dilution with decreasing concentrations of sucrose was applied. In PBS, LWh blastocysts (27%) had a lower viability in vitro than MS blastocysts (67%; P = 0.001). In TCM, no significant difference was observed between genotypes (41% for LWh and 43% for MS blastocysts) and both viability rates were lower than that of the control groups. In Experiment 2, morula-stage LWh and MS embryos were vitrified and warmed using PBS. The viability rate was low and did not differ between LWh (11%) and MS (14%). In Experiment 3, 200 MS and 200 LWh blastocysts were vitrified/warmed as described in Experiment 1 (PBS). In each of 20 MS recipients, 20 embryos were transferred. The farrowing rate was 55% and recipients farrowed four and five piglets (median) for MS and LWh blastocysts, respectively. The OPS method is therefore appropriate for cryopreservation of unhatched porcine blastocysts.
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PMID:Piglets born after vitrification of embryos using the open pulled straw method. 1103 90

Insulin-loaded microparticles were produced from blends of poly(ethylene glycol) (PEG) with poly (L-lactide) (PLA) homopolymer and poly (DL-lactide co-glycolide) copolymers (PLG) using a water-in-oil solvent extraction method. The dispersed phase was composed of PLG/PEG or PLA/PEG dissolved in dichloromethane, and the continuous phase was methanol containing 10% PVP. Characteristics, including particle size distribution, insulin loading capacity and efficiencies, in vitro release, degradation and stability, were investigated. The stability of insulin associated with microparticles prepared using PEG and 50:50 PLG and PLA was analysed by HPSEC and quantified by peak area following incubation in PBS at 37 degrees C for up to 1 month. Insulin was successfully entrapped in the PLG/PEG and PLA/PEG microparticles with trapping efficiencies up to 56 and 48%, loading levels 17.8 and 10.6% w/w, and particle sizes 8 and 3 microm, respectively. The insulin-loaded PLG/PEG and PLA/PEG microparticles were capable of controlling the release of insulin over 28 days with in vitro delivery rates of 0.94 and 0.65 microg insulin/mg particles/day in the first 4 days and a steady release with rate of 0.4 and 0.43 microg insulin/mg particles/day over the following 4 weeks, respectively. Extensive degradation of the PLG/PEG microparticles also occurred over 4 weeks, whereas the use of PLA/PEG blends resulted in a stable microparticle morphology and much reduced fragmentation and aggregation of the associated insulin.
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PMID:The stability of insulin in biodegradable microparticles based on blends of lactide polymers and polyethylene glycol. 1106 21


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