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Human Blood Plasma (human + blood_plasma)
Selected AbstractsInteraction of Plasma Deposited HMDSO-Based Coatings with Fibrinogen and Human Blood Plasma: The Correlation between Bulk Plasma, Surface Characteristics and Biomolecule InteractionPLASMA PROCESSES AND POLYMERS, Issue 5 2010Ram P. Gandhiraman Abstract The success of a biomaterial depends on the nature of interaction and the progressive reaction between the biological components and the surface of the biomaterial. In order to control the interaction between the biomaterial and biological component, it is necessary to understand the factors that influence the protein adsorption and cell proliferation. Surface chemistry plays a crucial role in the success of any blood contacting biomaterial. Plasma enhanced chemical vapour deposition (PECVD) is an interesting commonly used technique for tailoring surface characteristics while retaining bulk material properties. Two different films, namely polymer-like and silica-like coatings, with varying surface characteristics have been deposited from hexamethyldisiloxane, by PECVD, on 316L stainless steel. A correlation between the bulk plasma, interfacial adhesion of the coating to 316L steel, surface characteristics and biomolecule interaction is presented in this work. The interfacial adhesion strength analysis demonstrated that silica-like coatings have higher adhesion strength to 316L stainless steel than polymer-like coatings, caused due to the formation of a strong FeOSi and CrOSi bonds. It was observed that the effect of nanoscale surface roughness (close to 6,nm) was less significant, and that the surface chemistry played a significant role in governing the fibrinogen adsorption. Highest fibrinogen adsorption on plain steel was due to the electrostatic interaction of the metal oxide layer with the protein. Hydrophobicity of the polymer-like film resulted in a higher fibrinogen binding than the silica-like films. [source] Amperometric Sensor for Heparin: Sensing Mechanism and Application in Human Blood Plasma AnalysisELECTROANALYSIS, Issue 13-14 2006Jan Langmaier Abstract Voltammetric measurements of heparin at a rotating glassy carbon (GC) electrode coated with a polyvinylchloride membrane are reported. A spin-coating technique is used to prepare thin membranes (20,40,,m) with a composition of 25% (w/w) PVC, 1,1,-dimethylferrocene as a reference electron donor for the GC|membrane interface, nitrophenyl octyl ether (o -NPOE) or bis(2-ethylhexyl) sebacate (DOS) as a plasticizer, and hexadecyltrimethylammonium tetrakis(4-chlorophenyl) borate (HTMATPBCl) or tridodecylmethylammonium tetrakis(4-chlorophenyl) borate (TDMATPBCl) as a background electrolyte. It is shown that the electrodes coated with either the HTMA+/o -NPOE (DOS) or TDMA+/o -NPOE (DOS) membrane provide a comparable amperometric response towards heparin (1,10,U mL,1) in the aqueous solution of 0.1,M LiCl. However, only the membranes formulated with TDMATPBCl can be used for an amperometric assay of heparin in human blood plasma with a detection limit of 0.2,U mL,1. Effects of membrane composition, heparin concentration, rotation speed and sweep rate on the voltammetric behavior of heparin provide some insight into the sensing mechanism. Theoretical analysis of the amperometric response is outlined, and the numeric simulation of the voltammetric behavior is presented. [source] Hydrolysis of acetylthiocoline, o -nitroacetanilide and o- nitrotrifluoroacetanilide by fetal bovine serum acetylcholinesteraseFEBS JOURNAL, Issue 7 2009Marķa F. Montenegro Besides esterase activity, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) hydrolyze o -nitroacetanilides through aryl acylamidase activity. We have reported that BuChE tetramers and monomers of human blood plasma differ in o -nitroacetanilide (ONA) hydrolysis. The homology in quaternary structure and folding of subunits in the prevalent BuChE species () of human plasma and AChE forms of fetal bovine serum prompted us to study the esterase and amidase activities of fetal bovine serum AChE. The kcat/Km values for acetylthiocholine (ATCh), ONA and its trifluoro derivative N -(2-nitrophenyl)-trifluoroacetamide (F-ONA) were 398 × 106 m,1·min,1, 0.8 × 106 m,1·min,1, and 17.5 × 106 m,1·min,1, respectively. The lack of inhibition of amidase activity at high F-ONA concentrations makes it unlikely that there is a role for the peripheral anionic site (PAS) in F-ONA degradation, but the inhibition of ATCh, ONA and F-ONA hydrolysis by the PAS ligand fasciculin-2 points to the transit of o -nitroacetalinides near the PAS on their way to the active site. Sedimentation analysis confirmed substrate hydrolysis by tetrameric 10.9S AChE. As compared with esterase activity, amidase activity was less sensitive to guanidine hydrochloride. This reagent led to the formation of 9.3S tetramers with partially unfolded subunits. Their capacity to hydrolyze ATCh and F-ONA revealed that, despite the conformational change, the active site architecture and functionality of AChE were partially retained. [source] Composite coating of bonelike apatite particles and collagen fibers on poly L-lactic acid formed through an accelerated biomimetic coprecipitation processJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2006Yun Chen Abstract Collagen and apatite were coprecipitated as a composite coating on poly L-lactic acid (PLLA) in an accelerated biomimetic process. The incubation solution contained collagen (1 g/L) and simulated body fluid with 5 times inorganic ionic concentrations as human blood plasma. The coating formed on PLLA films and scaffolds after a 24-h incubation was characterized by using energy-dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM). It was shown that the coating contained carbonated bonelike apatite and collagen, which was similar in composition to natural bone. SEM showed a complex composite coating of submicron bonelike apatite particulates combined with collagen fibrils. It is expected that such biocomposite coating may better facilitate cell interaction and osteoconductivity. This work provided an efficient process to obtain bonelike apatite/collagen composite coating, which is potentially useful in bone tissue engineering. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source] Micropattern formation of apatite by combination of a biomimetic process and transcription of resist patternJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 4 2002Naoshi Ozawa Abstract Two kinds of methods combining a biomimetic process and transcription of resist pattern were conducted to form an apatite micropattern. For method 1, apatite nuclei were formed on a resist pattern printed substrate by setting it in contact with CaO-SiO2 -based glass in a simulated body fluid (SBF) with inorganic ion concentrations nearly equal to those of human blood plasma. Next, apatite was grown from the nuclei by soaking the substrate in an aqueous solution with ion concentrations 1.5 times those of SBF (1.5 SBF). Then, the resist material was dissolved off by organic solvent with the apatite just formed on it. Apatite micropattern transcribing the resist pattern was obtained. For method 2, apatite nuclei were formed on a resist pattern printed substrate by setting it in contact with CaO-SiO2 -based glass in SBF. Next, the resist material was dissolved off with the apatite nuclei just formed on it. Then, the substrate was soaked in 1.5 SBF to grow the remaining nuclei and an apatite micropattern transcribing the resist pattern was obtained. For both methods, minute apatite patterns with various shapes as straight lines, bending lines, and blocks were clearly formed. The minimum line width of the obtained pattern was 2 ,m. These methods are promising for producing multifunctional materials with bioaffinity. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 579,586, 2002 [source] Validation of an LC,MS Method for the Detection and Quantification of BZP and TFMPP and their Hydroxylated Metabolites in Human Plasma and its Application to the Pharmacokinetic Study of TFMPP in Humans,JOURNAL OF FORENSIC SCIENCES, Issue 5 2010Ushtana Antia M.Sc. Abstract:, An LC,MS method was developed for benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP), constituents of "party pills" or "legal herbal highs," and their metabolites in human blood plasma. Compounds were resolved using a mixture of ammonium formate (pH 4.5, 0.01 M) and acetonitrile (flow rate of 1.0 mL/min) with a C18 column. Calibration curves were linear from 1 to 50 ng/mL (R2 > 0.99); the lower limit of quantification (LLOQ) was 5 ng/mL; the accuracy was >90%; the intra- and interday relative standard deviations (R.S.D) were <5% and <10%, respectively. Human plasma concentrations of TFMPP were measured in blood samples taken from healthy adults (n = 6) over 24 h following a 60-mg oral dose of TFMPP: these peaked at 24.10 ng/mL (±1.8 ng/mL) (Cmax) after 90 min (Tmax). Plasma concentrations of 1-(3-trifluoromethyl-4-hydroxyphenyl) piperazine peaked at 20.2 ng/mL (±4.6 ng/mL) after 90 min. TFMPP had two disposition phases (t½ = 2.04 h (±0.19 h) and 5.95 h (±1.63 h). Apparent clearance (Cl/F) was 384 L/h (±45 L/h). [source] Detection and validated quantification of nine herbal phenalkylamines and methcathinone in human blood plasma by LC-MS/MS with electrospray ionizationJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 2 2007Jochen Beyer Abstract The herbal stimulants Ephedra species, Catha edulis (khat), and Lophophora williamsii (peyote) have been abused for a long time. In recent years, the herbal drug market has grown owing to publicity on the Internet. Some ingredients of these plants are also ingredients of cold remedies. The aim of the presented study is to develop a multianalyte procedure for detection and validated quantification of the phenalkylamines ephedrine, pseudoephedrine, norephedrine, norpseudoephedrine, methylephedrine, methylpseudoephedrine, cathinone, mescaline, synephrine (oxedrine), and methcathinone in plasma. After mixed-mode solid-phase extraction of 1 ml of plasma, the analytes were separated using a strong cation exchange separation column and gradient elution. They were detected using a Q-Trap LC-ESI-MS/MS system (MRM mode). Calibration curves were used for quantification using norephedrine- d3, ephedrine- d3, and mescaline- d9 as internal standards. The method was validated according to international guidelines. The assay was selective for the tested compounds. It was linear from 10 to 1000 ng/ml for all analytes. The recoveries were generally higher than 70%. Accuracy ranged from , 0.8 to 20.0%, repeatability from 2.5 to 12.3%, and intermediate precision from 4.6 to 20.0%. The lower limit of quantification was 10 ng/ml for all analytes. No instability was observed after repeated freezing and thawing or in processed samples. The applicability of the assay was tested by analysis of authentic plasma samples after ingestion of different cold medications containing ephedrine or pseudoephedrine, and after ingestion of an aqueous extract of Herba Ephedra. After ingestion of the cold medications, only the corresponding single alkaloids were detected in human plasma, whereas after ingestion of the herb extract, all six ephedrines contained in the plant were detected. The presented LC-MS/MS assay was found applicable for sensitive detection and accurate and precise quantification of all studied analytes in plasma. Copyright © 2006 John Wiley & Sons, Ltd. [source] Precipitation of Carbonated Calcium Phosphate Powders from a Highly Supersaturated Simulated Body Fluid SolutionJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2007Ingo Hofmann Carbonated hydroxy apatite (CHA) powders were prepared by precipitation from a modified simulated body fluid (5 × M-SBF). The ionic concentrations were five times higher than in human blood plasma with the exception of Mg2+ and HCO3, concentrations that were reduced in order to accelerate crystal growth. Spheroaggregates of CHA platelets with molar (Ca+Mg)/P ratios ranging from 1.44 to 1.56 were obtained after precipitation at 50°C. The crystallite size in the c direction was approximately 31 nm and depending on the precipitation time, a CO32, content of 1.8,5.2 wt% was determined. Using this low-temperature precipitation method, CHA powders with a high specific surface area of 83 m2/g and a composition and crystallite size close to those of the mineral phase of human bone were obtained. [source] Influence of peptide ligand surface density and ethylene oxide spacer arm on the capture of porcine parvovirusBIOTECHNOLOGY PROGRESS, Issue 5 2009Caryn L. Heldt Abstract In previous work, we identified two trimeric peptide ligands (designated WRW and KYY), which bound specifically to porcine parvovirus (PPV) and demonstrated their ability to capture and remove the virus from solutions containing 7.5% human blood plasma. This article examines the influences of peptide density and the presence of an ethylene oxide spacer arm on the efficiency of virus capture using these two ligands. The WRW peptide bound the most virus from plasma solutions at the lowest peptide density tested (0.008 mmol/g dry resin), and binding was enhanced by the presence of the spacer arm. On the other hand, the KYY peptide bound the most viruses at the same low peptide density, but it performed better in the absence of the spacer arm. Of the two, the binding efficiency of the WRW peptide was more sensitive to peptide density and spacer arm presence. These results indicate that low peptide densities enhance binding selectivity, facilitating specific peptide-virus binding even in the presence of plasma proteins which can theoretically bind nonspecifically. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] | |||||||||||||