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Query: UNIPROT:P30536 (PBS)
 9,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chitosan nanoparticles (CS NP) with various formations were produced based on ionic gelation process of tripolyphosphate (TPP) and chitosan. They were examined with diameter 20-200 nm and spherical shape using TEM. FTIR confirmed tripolyphosphoric groups of TPP linked with ammonium groups of chitosan in the nanoparticles. Factors affecting delivery properties of bovine serum albumin (BSA) as model protein have been tested, they included molecular weight (Mw) and deacetylation degree (DD) of chitosan, the concentration of chitosan and initial BSA, and the presence of polyethylene glycol (PEG) in encapsulation medium. Increasing Mws of chitosan from 10 to 210 kDa, BSA encapsulation efficiency was enhanced about two times, BSA total release in PBS (phosphate buffer saline) pH 7.4 in 8 days was reduced from 73.9 to 17.6%. Increasing DD from 75.5 to 92% promoted slightly the encapsulation efficiency and decelerated the release rate. The encapsulation efficiency was highly decreased by increase of initial BSA and chitosan concentration; higher loading capacity of BSA speeded the BSA release from the nanoparticles. Adding PEG hindered the BSA encapsulation and accelerated the release rate.
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PMID:Effect of molecular structure of chitosan on protein delivery properties of chitosan nanoparticles. 1248 Feb 87

A simple, rapid, and sensitive reversed-phase high-performance liquid chromatographic (HPLC) method for the measurement of mupirocin concentrations in both skin layers and percutaneous samples has been developed. Mupirocin was extracted from skin layers using PBS-acetonitrile (90:10, v/v). The method is sufficiently sensitive and repeatable to be used in percutaneous penetration studies. The samples were chromatographed on a 250 mm x 4 mm C(8) LiChrospher Select B (5 microm). The mobile phase composition was a mixture of acetonitrile-ammonium acetate 0.05 M (27.5:72.5, v/v) adjusted to pH 6.3 with acetic acid. The analyte was detected at 228 nm and the run time was 11 min. Linearity was confirmed in the concentration range 0.2-20 microg/ml and the limit of detection was 9.5 ng/ml.
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PMID:Development and validation of a liquid chromatographic method for in vitro mupirocin quantification in both skin layers and percutaneous penetration studies. 1458 Oct 64

A novel approach potentially useful for the development of more thromboresistant polymeric materials is examined. The method is based on the catalytic generation of nitric oxide (NO) via Cu(I) mediated reduction of nitrite ions. Preliminary solution phase studies demonstrate that ascorbate or thiolate anions can generate Cu(I) from Cu(II) with subsequent catalytic conversion of any nitrite ions present to NO by the unstable Cu(I) species. Incorporation of this same chemistry within a hydrophobic polymeric material requires immobilizing Cu(II) ions into a polymeric phase via use of a lipophilic Cu(II) chelating ligand (dibenzo [e,k]-2,3,8,9-tetraphenyl-1,4,7,10-tetraaza-cyclododeca-1,3,7,9-tetraene (DTTCT)). It is shown that this complex can be reduced to its Cu(I) form by appropriate reducing equivalents present in the bathing solution. The resulting Cu(I) complex can then reduce nitrite to NO with the NO generation occurring at the polymer/solution interface at physiological pH. Data from chemiluminescence experiments indicate that the flux of NO at the polymer surface is comparable to that of endothelial cells (>/=1x10(-10)mol/cm(2)min) when 0.5mM nitrite/1mM ascorbate are present in the bathing solution. Potentially more useful NO generation can be achieved by doping the polymer film with the Cu(II) complex along with a lipophilic quaternary ammonium nitrite salt. In this case reducing equivalents within the aqueous phase enable the nitrite derived from the polymer to be converted into NO by the Cu(II/I) ligand complex. Films of this type are shown to generate NO for at least 6h in PBS buffer with fluxes on the order of 1.5x10(-10)mol/cm(2)min. Physiologically relevant levels of NO release are also shown to exist at the polymer interface when films are soaked in fresh plasma as well as undiluted whole blood, indicating that endogenous reducing equivalents present in blood can efficiently reduce the Cu(II)-ligand within the polymer film. The prospects of using these new NO releasing films to devise more biocompatible polymeric coatings for biomedical applications are discussed.
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PMID:Catalytic generation of nitric oxide from nitrite at the interface of polymeric films doped with lipophilic CuII-complex: a potential route to the preparation of thromboresistant coatings. 1458 16

Determination of the kinetics of water-soluble degradation products inside poly(lactide-co-glycolide) (PLGA) delivery systems during polymer degradation is important to evaluate the polymer microclimate conditions, particularly microclimate pH changes for optimization of encapsulated drug stability. A pre-derivatization high-performance liquid chromatography (HPLC) method was developed for separation and quantification of water-soluble acid impurities and degradation products in PLGA. Thin PLGA films (approximately 200 microm) were incubated in PBS/0.02% Tween 80, pH 7.4, for 6 weeks. Water-soluble monomers and oligomers were obtained from polymer films after repeated CHCl(3)/H(2)O extraction and then derivatized into bromophenacyl esters. With the common chromophore, the esters were separated and quantified by HPLC with increased ultraviolet (UV) sensitivity at 254 nm. The total amount of water-soluble acids in the extract was validated by potentiometric titration with tetrabutyl ammonium hydroxide. During the first 3 weeks of incubation of PLGA 50:50 (inherent viscosity = 0.63 dL/g), the principal water-soluble acids in the polymer were glycolic, lactic, and lactoyllactic acids, and an unknown oligomer. After 4 weeks of incubation, a large fraction of higher molecular weight oligomers was observed. Pre-derivatization HPLC can be used to accurately measure water-soluble acid distribution, and may be invaluable to examine the degradation behavior of PLGAs, including the underlying mechanism of polymer microclimate pH development.
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PMID:Determination of water-soluble acid distribution in poly(lactide-co-glycolide). 1470 90

Seminal plasma (SP) is known to have immunosuppressive properties in several species. Equine SP has been reported to reduce or inhibit chemotaxis, phagocytosis and complement activity in vitro. The type and amount of the SP component that suppresses sperm-polymorphonuclear neutrophil (PMN) binding in vitro was determined, and the effect of such suppression on the fertility of mares inseminated in the presence of uterine inflammation, was analyzed. Sperm cells were suspended in either SP, semen extender or a mixture of both, and each was mixed with PMN-rich uterine secretions collected at 12 h after artificial insemination (AI). SP reduced binding between spermatozoa and PMNs significantly (P < 0.05). Fertile spermatozoa were suspended in SP or semen extender and used to inseminate mares 12 h after the induction of uterine inflammation. The pregnancy rate was normal (77%) when spermatozoa were suspended in SP, but was dramatically reduced to only 5% when spermatozoa were suspended in extender. The proteins from SP, blood plasma (BP) and a skim-milk-based semen extender (skim milk extender, SME) were precipitated by ammonium sulfate, resuspended in PBS and dialyzed. The effect of the precipitated proteins on sperm-PMN binding was compared with fresh, untreated SP. Both fresh SP, and isolated SP proteins reduced sperm-PMN binding (P < 0.001). Conversely, proteins isolated from either BP or SME did not reduce sperm-PMN binding. The different concentrations of SP proteins used showed a dose-dependent suppression of sperm-PMN binding. Concentrations of 1 mg/ml SP protein significantly reduced sperm-PMN binding and 6 mg/ml reduced the binding to a level similar to that observed with fresh whole SP (P < 0.001). Finally, SP protein digested with proteinase K resulted in the complete loss of SP suppressive activity confirming that the effective component is a proteinaceous substance.
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PMID:Equine seminal plasma reduces sperm binding to polymorphonuclear neutrophils (PMNs) and improves the fertility of fresh semen inseminated into inflamed uteri. 1512 15

The soybean agglutinin (SBA) was separated with hydrophobic-interaction chromatography (HIC) in this work. HIC of the crude lectin extract of SBA was performed on Phenyl-Sepharose CL-4B column, 10 cm x 2.5 cm i.d., at a flow-rate of 1.0 mL/min. A 20 mL sample of the crude extract was applied to the column previously equilibrated with the buffer, 0.01 mol/L PBS containing ammonium sulfate (60% of saturation concentration). The column was eluted with the starting buffer, then with the buffer containing 30% saturation of ammonium sulfate, and finally with 0.01 mol/L PBS. Fractions were detected by UV absorbance at 280 nm and assayed for hemagglutinating activity. The results show that the purification-fold was as high as 35 and the recovery of activity was 100%.
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PMID:[Separation of soybean agglutinin by hydrophobic-interaction chromatography]. 1573 41

A study was undertaken to determine the effects of oviductal proteins obtained from various stages of the estrous cycle on spermatozoa characteristics in buffaloes. Oviducts were collected from apparently healthy buffalo genital tracts (nonluteal and luteal stage of estrous cycle) and separated into isthmus and ampulla. Each segment of oviduct (nonluteal and luteal) was flushed with PBS (pH 7.4). The flushing obtained was centrifuged (3000 rpm; 30 min), filtered (0.2 microm) and frozen at -20 degrees C. The proteins in pooled nonluteal isthmic and ampullary and luteal isthmic and ampullary fluids were precipitated overnight using ammonium sulphate, centrifuged (10000 rpm; 30 min) and dialyzed (>10 kDa). After protein estimation, aliquots of samples containing 10 mg proteins were lyophilized in cryovials and stored in frozen form at -20 degrees C. Six pooled good-quality ejaculates collected by artificial vagina method from two Murrah buffalo bulls were utilized for the study. After fresh semen analysis, each pooled ejaculate was splited into five parts and extended in Tris-egg yolk-citrate extender (20% egg yolk; 7% glycerol), so that final dilution yielded approximately 60 million sperm cells per ml, and cryopreserved in 0.5 ml French straws (30 million sperm cells/straw) in LN(2) (-196 degrees C). Before freezing, nonluteal isthmic and ampullary and luteal isthmic and ampullary proteins were incorporated at the rate of 1mg/ml of extended semen. The equilibrated and frozen-thawed (37 degrees C for 30 s) semen was evaluated for motility, live %, acrosomal integrity percentage, bovine cervical mucus penetration test and hypo-osmotic sperm swelling test. Besides this, spermatozoa from treatment and control groups were incubated at 37 degrees C for 6 h in sperm TALP. Among the nonluteal and luteal oviductal proteins, the former maintained higher (P < 0.05) post-thaw sperm motility, live %, and acrosomal integrity than the control group. Between the isthmic and ampullary proteins, the isthmic proteins incorporated group maintained higher (P < 0.05) post-thaw sperm motility, live %, and acrosomal integrity. Similarly, higher sperm penetration distance in cervical mucus was recorded in nonluteal isthmic proteins incorporated group. But, irrespective of the stage of an estrous cycle, isthmic proteins included group maintains higher sperm membrane integrity as revealed by higher (P < 0.05) swollen sperm percentage in response to hypo-osmotic solution than the ampullary proteins included and control groups. Similarly, at any time during incubation the sperm motility and viability was higher (P < 0.05) in isthmic proteins treated group than the ampullary and control group. But, the same trend was not observed in terms of acrosomal integrity percentages. It is inferred that inclusion of oviductal proteins in the extender prior to freezing improved post-thaw semen quality. Oviductal proteins differentially affected sperm function depending upon the region of oviduct and the stage of estrous cycle at which the proteins were obtained.
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PMID:Modulation of post-thaw sperm functions with oviductal proteins in buffaloes. 1595 Apr 8

Protein disulfide isomerase-related protein A (PRPA) was highly expressed (about 34%) in Escherichia coli by inserting the whole PRPA cDNA into the vector pET23b. After expression, the purified protein was acquired through ammonium fractional precipitation and Bio-Rex 70 chromatography. PRPA shows low disulfide isomerase activity (only about 1/250 of that of hPDI), decreases the reactivation yield of denatured and reduced lysozyme either in redox and non-redox Hepes buffer or redox PBS buffer and facilitates the aggregation of denatured and reduced lysozyme. Fluorescence spectra of PRPA indicate that PRPA has more hydrophobic groups at surface than that of hPDI, and which can be used to explain why PRPA has anti-chaperone activity during the refolding of denatured and reduced lysozyme.
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PMID:[Expression and characterization of protein disulfide isomerase-related protein A]. 1596 95

Bovine oocytes, before and after maturation in culture, were stored in PBS with 2 M-(NH(4))(2)SO(4) + 0.1% dextran or 2 M-(NH(4))(2)SO(4) + 40 mM-Hepes + 0.5% dextran and were inseminated with frozen-thawed spermatozoa in BO medium with caffeine (5 mM) and heparin (10 mug/ml). The penetration rates of mature oocytes were very low (19 to 24%) and not significantly different between the two salt solutions in which the oocytes were stored for 2 to 89 days. Significantly lower (P < 0.01) penetration rates were observed in immature (7 to 8%) than in mature (20 to 21%) oocytes stored in the two solutions. The synergistic effect of caffeine and heparin was observed in the penetration rate of fresh mature oocytes but not in the stored oocytes, indicating the difficulty of assessing sperm capacitation and/or acrosome reaction of salt-stored mature bovine oocytes under the present condition. Using 0.1% protease the solubility of the zonae decreased in salt-stored but not in fresh oocytes, but there was no significant difference between the immature and mature oocytes regardless of storage in the salt solutions. It appears from these results that some alteration was induced in the nature of zona glycoprotein by ammonium sulfate solution.
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PMID:In vitro penetration of zona pellucida of salt-stored bovine oocytes before and after maturation by frozen-thawed spermatozoa. 1672 94

Sinomenine (7,8-didehydro-4-hydroxy-3,7-dimethoxy-17-methylmorphinan-6-one) is a pure alkaloid extracted from the Chinese medical plant. In this report a liquid chromatography-electrospray mass spectrometry (LC-ESI-MS) method with in vivo microdialysis for the pharmacokinetic study of free-form sinomenine in rat skin has been developed. A microdialysis probe was surgically implanted into the subcutaneous tissue of the rats and an isotonic phosphate buffer (PBS) was used as the perfusion medium. Samples were collected and then analyzed off-line by LC-ESI-MS. The chromatographic separation was achieved within 4.2 min by using a narrow-bore Xterra C(18) column (2.1 x 150 mm, 5 microm) with acetonitrile-(10 mmol/L ammonium acetate buffer, 0.1% acetic acid) (15:85, v/v). Ion signal m/z 330.1 for sinomenine was measured in the positive mode. Linearity was established for the range of concentrations of 2.0-10000.0 ng/mL with a coefficient of determination (r) of 0.9989. The intra- and inter-day reproducibility of the present method was better than 6%. The lower limit of quantification (LLOQ) was 1.0 ng/mL. The proposed method described provides more authentic information on pharmacokinetics and metabolism at the site of action by using the coupling of microdialysis to LC-ESI-MS technique than the traditional sampling methods.
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PMID:Pharmacokinetic study of free-form sinomenine in rat skin by microdialysis coupled with liquid chromatography-electrospray mass spectrometry. 1712 Mar 5


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