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Performance Liquid Chromatography (performance + liquid_chromatography)
Kinds of Performance Liquid Chromatography Selected AbstractsDETERMINATION OF BENZO(a)PYRENE IN VEGETABLE OILS BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHYJOURNAL OF FOOD QUALITY, Issue 3 2007EKERO, LU GÜLTEN ABSTRACT Analysis of 40 oil samples showed that 38 of them were contaminated with benzo(a)pyrene (BaP). Thirty of the 38 BaP-contaminated edible oil samples did not have any label of a brand name. BaP content for the 38 contaminated edible oil samples were in the range of 1.22,74.89 ppb. Sixteen of the contaminated oil samples had BaP content of more than 10 ppb, which is the maximum tolerable limit for the Turkish Food Codex Regulation. BaP contents of samples for each type of oil were significantly different (P < 0.05) from each other. [source] PURIFICATION AND CHARACTERIZATION OF BACTERIOCIN FROM WEISSELLA PARAMESENTEROIDES DFR-8, AN ISOLATE FROM CUCUMBER (CUCUMIS SATIVUS)JOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2010AJAY PAL ABSTRACT Bacteriocin from Weissella paramesenteroides DFR-8 isolated from cucumber (Cucumis sativus) was purified by using only two steps, viz., pH-mediated cell adsorption,desorption method and gel permeation chromatography. A single peak observed in the purity check by analytical Reverse Phase-High Performance Liquid Chromatography (Waters 600 analytical HPLC system, Milford, MA) and a single band (molecular weight,3.74 kDa) shown on SDS-PAGE analysis strongly indicated the homogeneity of the bacteriocin preparation. Treatment with proteolytic enzymes abolished the antimicrobial activity indicating the proteinaceous nature of bacteriocin. The purified bacteriocin exhibited a broad inhibitory spectrum against foodborne pathogens and spoilage microorganisms, including gram-negative bacteria such as Salmonella typhimurium, Vibrio parahaemolyticus, Aeromonas hydrophila and Listeria monocytogenes. Response surface methodology was employed to study the interactive effect of temperature and pH on bacteriocin activity, and a regression equation was developed. The bacteriocin retained full activity after storage at,20C for 90 days, while partial and complete activity loss was observed when stored at 4 and 37C, respectively. PRACTICAL APPLICATION In recent years, bacteriocins of lactic acid bacteria have gained much attention as food biopreservatives because of their origin from generally regarded as safe organisms. In spite of various bacteriocins studied worldwide, studies on bacteriocins of Weissella paramesenteroides remain rare. The present work involves the purification of bacteriocin up to absolute homogeneity from W. paramesenteroides, an isolate first time reported from cucumber (Cucumis sativus). The purified bacteriocin (molecular weight ,3.74 kDa) was found to inhibit a large number of foodborne pathogens, including Listeria monocytogenes, which is resistant to commercially available bacteriocin, i.e., nisin. The application of central composite rotatable design enabled us to design a regression equation from which the residual activity of bacteriocin can be predicted at any given conditions of temperature and pH within the experimental domain. The broad inhibitory spectrum and thermostability of bacteriocin suggest its potential application in food preservation. [source] Research Article: Fingerprinting Analysis of Saposhnikovia divaricata using 1H Nuclear Magnetic Resonance Spectroscopy and High Performance Liquid ChromatographyJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2010Yue-Yang Xin The 1H nuclear magnetic resonance (1H NMR) fingerprints of fractionated non-polar and polar extracts (control substance for plant drug [CSPD] A and B) from the roots of 12 specimens of Saposhnikovia divaricata (Turcz.) Schischk were achieved with Fourier Transform (FT)-NMR spectrometer and assigned by comparison to each other and to the 1H NMR spectra of the isolated individual compounds. These fingerprints were found to be uniform in terms of the specificity for the implication of all 12 specimens being systematically of the same origin. The uniformity was further affirmed by high performance liquid chromatography (HPLC), which also revealed exactly identical specificity for the identified S. divaricata species with the 1H NMR appearances of corresponding CSPD on the part of the composition of characteristic constituents when comparing to corresponding individual compounds. This investigation unambiguously shows that the specific signals from the chemotaxonomically significant compounds of chromones and coumarins in S. divaricata are exhibited distinctively in the composite features of both 1H NMR fingerprints and HPLC profiles. The 1H NMR and HPLC profiles established can successfully be used as reference for the authentication of the origin of S. divaricata species as well as for chemotaxonomic studies. [source] Evaluation of a Non-Targeted "Omic" Approach in the Safety Assessment of Genetically Modified PlantsPLANT BIOLOGY, Issue 5 2006S. B. Metzdorff Abstract: Genetically modified plants must be approved before release in the European Union, and the approval is generally based upon a comparison of various characteristics between the transgenic plant and a conventional counterpart. As a case study, focusing on safety assessment of genetically modified plants, we here report the development and characterisation of six independently transformed Arabidopsis thaliana lines modified in the flavonoid biosynthesis. Analyses of integration events and comparative analysis for characterisation of the intended effects were performed by PCR, quantitative Real-time PCR, and High Performance Liquid Chromatography. Analysis by cDNA microarray was used as a non-targeted approach for the identification of potential unintended effects caused by the transformation. The results revealed that, although the transgenic lines possessed different types of integration events, no unintended effects were identified. However, we found that the majority of genes showing differential expression were identified as stress-related genes and that environmental conditions had a large impact on the expression of several genes, proteins, and metabolites. We suggest that the microarray approach has the potential to become a useful tool for screening of unintended effects, but state that it is crucial to have substantial information on the natural variation in traditional crops in order to be able to interpret "omics" data correctly within the framework of food safety assessment strategies of novel plant varieties, including genetically modified plant varieties. [source] Lornoxicam pharmacokinetics in the vitreous humor of albino rabbitsACTA OPHTHALMOLOGICA, Issue 2009C TSIKA Purpose To assess the elimination half-life of intravitreal lornoxicam, a non-steroidal anti-inflammatory drug (NSAID). Methods Both eyes of 15 rabbits were intravitreally injected with 250 ,g of commercially available lornoxicam (for intravenous/intramuscular use, Xefo® 8 IV/IM Injection, Nycomed Hellas S.A.). Six eyes were enucleated at time points 0, 1, 2, 6 and 24 hours after the injection was performed. The eyes were immediately frozen at -80°C. The vitreous was eviscerated from the eye and the drug was liquid-liquid extracted from a 0.4 ml sample. Lornoxicam was isolated by a reversed-phase High Performance Liquid Chromatography (HPLC) method at retention time 10.7 min and detected at 372 nm. The data were statistically analyzed in order to evaluate the pharmacokinetic parameters of the drug. Results The recovery of lornoxicam after liquid-liquid extraction was calculated at 69.6% and the limit of determination was 0.1 ,g/ml. Statistical analysis revealed that lornoxicam concentrations followed first-order kinetics with an elimination rate constant of 0.235h-1 and a half-life of 3.0 h. Conclusion The determination of the pharmacokinetic characteristics of intravitreal lornoxicam allows the possibility for further investigation of the drug's intraocular behaviour and therapeutic potential. [source] Simultaneous Determination of Epinephrine, Noradrenaline and Dopamine in Human Serum Samples by High Performance Liquid Chromatography with Chemiluminescence DetectionCHINESE JOURNAL OF CHEMISTRY, Issue 7 2007Fu-Nan Chen Abstract A simple, rapid and accurate high performance liquid chromatographic (HPLC) technique coupled with chemiluminescence (CL) detection was developed for the simultaneous determination of epinephrine (E), noradrenaline (NA) and dopamine (DA). It was based on the analyte enhancement effect on the CL reaction between luminol and potassium ferricyanide. The effects of various parameters, such as potassium ferricyanide concentration, luminol concentration, pH value and component of the mobile phase on chromatographic behaviors of the analytes (E, NA and DA) were investigated. The separation was carried out on C18 column using the mobile phase of 0.01 mol/L potassium hydrogen phthalate solution and methanol (92:8, V/V). Under the optimum conditions, E, NA and DA showed good linear relationships in the range of 1×10,8,5×10,6, 5.0×10,9,1.0×10,6 and 5.0×10,9,1.0×10,6 g/mL respectively. The detection limits for E, NA and DA were 4.0×10,9, 1.0×10,9 and 8.0×10,10 g/mL. The proposed method has been applied successfully to the analysis of E, NA and DA in human serum samples. [source] Optimizing the Quadruple-potential Waveform for the Determination of Gentamicin Sulfate by High Performance Liquid Chromatography with Pulsed Electrochemical DetectionCHINESE JOURNAL OF CHEMISTRY, Issue 9 2005Ya-Qi Cai Abstract In this paper, a quadruple-potential waveform was investigated and optimized for the determination of gentamicin by reversed phase ion-pair chromatography. Instead of a relatively high positive potential, a negative potential was adopted as a potential for the cleaning of gold working electrode. By this way, the formation of gold oxide resulting from the application of high positive potential during the analyte detection and electrode cleaning was greatly reduced, and therefore, the dissolution and recession of gold working electrode was also reduced. The good condition of gold working electrode achieved by this quadruple-potential waveform can help us to obtain a good reproducibility. In order to acquire signal-to-noise ratio as high as possible, several waveform parameters affecting the detection of gentamicin were carefully selected. The analytical method has been applied to the determination of two real gentamicin samples, and good results with low relative standard deviation not more than 4% were obtained. [source] PRODUCTION AND BIOCHEMICAL CHARACTERIZATION OF SCLEROTINIA SCLEROTIORUM ,-AMYLASE ScAmy1: ASSAY IN STARCH LIQUEFACTION TREATMENTSJOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2008IMEN BEN ABDELMALEK KHEDHER ABSTRACT Among the lytic enzymes secreted by the phytopathogen fungus Sclerotinia sclerotiorum, a starch-degrading activity has been isolated and characterized. Two extracellular ,-amylases were produced in culture medium in presence of oats flour as carbons sources. An endoamylase named ScAmy1 was purified to homogeneity by ammonium sulfate precipitation, phosphocellulose and cation exchange high performance liquid chromatographies. Molecular mass of purified ScAmy1 was estimated as 54 kDa. Amylase exhibits maximal activity at pH 5 to 6 and at temperature 60C. ScAmy1 was stable in a pH range of (5,11) and at 50C. Initial activity was still conserved 40%, after heating at 60C during 30 min. In addition, Ca2+activate and stabilize the enzyme. Starch end products were determined as low molecular oligoglucanes, the liquefying power of ScAmy1 was also tested with the Amylograph Brabender, results suggest a suitable application of ScAmy1 in several industrial process. PRACTICAL APPLICATIONS ,-Amylase ScAmy1 was highly produced from Sclerotinia sclerotiorum on oats flour , a cheaper by-agro-substrate product. The enzyme was purified and biochemical characterized. ScAmy1 was applied in starch liquefaction treatments assay. The enzyme allows a decrease in peak viscosity after gelatinization and therefore has an important liquefying power. ScAmy1 has a nearly liquefaction effect on flour compared to the commercial enzyme Novamyl, from Novozymes, donated by Novo Nordisk Co. (Denmark). Enzyme end products were analyzed and identified as oligoglucanes and dextrins. Those are widely applied in food, paper, textile and pharmacological industries. Oligosaccharides are useful as prebiotics as dietary fiber or slowly digestible starch derivatives, and they can be used in form of supplement to certain foodstuffs. [source] Reduced plasma total homocysteine concentrations in Type 1 diabetes mellitus is determined by increased renal clearanceDIABETIC MEDICINE, Issue 3 2005B. A. J. Veldman Abstract Introduction Elevated plasma levels of total homocysteine are related to the development of vascular complications. Patients with diabetes mellitus are particularly at risk for the development of these complications. Several factors determine plasma total homocysteine including renal function. Aims As early Type 1 diabetes is characterized by a relative glomerular hyperfiltration, increased renal clearance could contribute to decreased levels of homocysteine as observed in Type 1 diabetes mellitus. Therefore we investigated the relationship between plasma total homocysteine and the glomerular filtration rate (GFR). Methods In 92 Type 1 diabetes patients and 44 control subjects, we measured GFR and effective renal plasma flow (ERPF) by means of continuous infusion of inulin and p-aminohippurate. Fasting plasma total homocysteine was measured using high performance liquid chromatography. Results GFR (121 ± 21 resp. 104 ± 14 ml/min; P < 0.001) and ERPF (563 ± 127 resp. 516 ± 121 ml/min; P = 0.05) were significantly higher in Type 1 diabetes patients as compared with control subjects. Plasma total homocysteine was reduced in Type 1 diabetes patients as compared with control subjects (11.0 ± 4.5 resp. 13.4 ± 7 µmol/l; P = 0.01). Plasma total homocysteine was strongly correlated with GFR (Type 1 diabetes patients: r = ,0.43, P < 0.001; control subjects: r = ,0.39, P = 0.01). Conclusion GFR is a major determinant of plasma total homocysteine levels in Type 1 diabetes patients as well as control subjects. The reduced plasma total homocysteine levels in diabetes patients can be explained by an increased GFR. [source] A rapid screening LC-MS/MS method based on conventional HPLC pumps for the analysis of low molecular weight xenobiotics: application to doping control analysisDRUG TESTING AND ANALYSIS, Issue 7 2010Monica Mazzarino Abstract This study presents a fast multi-analyte screening method specifically developed for the detection of xenobiotics in urine. The proposed method allows the screening of several classes of substance in a single chromatographic method with a run-time of 11 min, inclusive of post-run and reconditioning times. Chromatographic separation is achieved in 7.2 min using a reversed-phase 2.7 µm fused-core particle column, generating a back-pressure not exceeding 400 bar and therefore enabling the use of traditional high performance liquid chromatography (HPLC) instruments. The effectiveness of this approach was evaluated, by liquid-chromatography tandem mass spectrometry (LC-MS/MS) in positive electrospray ionization, using 20 blank urine samples spiked with 45 compounds prohibited in sport: 11 diuretics, 16 glucocorticoids, 9 stimulants, 5 anti-oestrogens, as well as formoterol, carboxy-finasteride (previously prohibited by the World Anti-Doping Agency (WADA) in 2008), gestrinone and tetrahydrogestrinone. Qualitative validation shows the proposed method to be specific with no significant interference. All of the analytes considered in this study were clearly distinguishable in urine, with limits of detection ranging from 5 ng/mL to 350 ng/mL, significantly below the Minimum Required Performance Levels (MRPL) set by WADA for the accredited sports anti-doping laboratories. All compounds of interest were separated, including synthetic and endogenous glucocorticoids with similar retention times and fragmentation patterns. Copyright © 2010 John Wiley & Sons, Ltd. [source] Pulsed Amperometric Detection of Histamine at Glassy Carbon Electrodes Modified with Gold NanoparticlesELECTROANALYSIS, Issue 4 2005V. Carralero Abstract Gold nanocrystal-modified glassy carbon electrodes (nAu-GCE) were prepared and used for the determination of histamine by flow injection and high performance liquid chromatography using pulsed amperometric detection (PAD) as the detection mode. Experimental variables involved in the electrodeposition process of gold from a HAuCl4 solution were optimized. A catalytic enhancement of the histamine voltammetric response was observed at the nAu-GCE when compared with that obtained at a conventional Au disk electrode, as a consequence of the microdispersion of gold nanocrystals on the GC substrate. The morphological and electrochemical characteristics of the nAu-GCE were evaluated by SEM and cyclic voltammetry. PAD using a very simple potential waveform consisting of an anodic potential (+700,mV for 500,ms) and a cathodic potential (,300,mV for 30,ms), was used to avoid the electrode surface fouling when histamine was detected under flowing conditions. Flow injection amperometric responses showed much higher Ip values and signal-to-noise ratios at the nAu-GCE than at a conventional gold disk electrode. A limit of detection of 6×10,7,mol L,1 histamine was obtained. HPLC-PAD at the nAu-GCE was used for the determination of histamine in the presence of other biogenic amines and indole. Histamine was determined in sardine samples spiked at a 50,,g g,1 concentration level, with good results. Furthermore, the chromatographic PAD method was also used for monitoring the formation of histamine during the decomposition process of sardine samples. [source] Characterization and Assessment of the Microjet Electrode as a Detector for HPLCELECTROANALYSIS, Issue 9 2004Susan Cannan Abstract The microjet electrode (MJE) is characterized as a detector for high performance liquid chromatography (HPLC). Voltammetric measurements of the oxidation of hydroquinone (HQ) allow mass transport to be determined for the MJE detector configuration, and the factors controlling the conversion efficiency of the device to be well understood. The current-time response to the flow injection analysis of volumes of solution in the 10,80,,L range has been established, and the limit of detection of this method has been determined. The latter was found to approach that of UV absorbance measurements, which is particularly encouraging, given that HQ has a relatively strong chromophore (,=2,290.8,cm,1 mol,1,L). This detection system is a robust and simple arrangement with the capability of analyzing large volumes of eluent at typical analytical HPLC flow rates. [source] Production of Taxol fromPhyllosticta spinarum, an endophytic fungus ofCupressus sp.ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 4 2008R. Senthil Kumaran Abstract Taxol production during the cultivation on a modified liquid and potato dextrose broth medium was indicated for the first time to occur in Phyllosticta spinarum, an endophytic fungus isolated from the needles of Cupressus sp. The presence of taxol in the fungal culture filtrate was confirmed by chromatographic and spectroscopic methods of analysis. The amount of taxol produced by this fungus was quantified by high performance liquid chromatography. The maximum amount of taxol production was obtained in this fungus when grown on M1D medium (235,,g/L) followed by PDB medium (125,,g/L). The results indicate that P.,spinarum is an excellent candidate for taxol production. The production rate was 4.7,×,103 -fold higher than that found in the culture broth of an earlier reported fungus, Taxomyces andreanae. The fungal taxol extracted also showed a strong cytotoxic activity in the in vitro culture of human cancer cells tested in an apoptotic assay. [source] Toxicology of a Microcystis ichthyoblabe waterbloom from Lake Oued Mellah (Morocco)ENVIRONMENTAL TOXICOLOGY, Issue 1 2002Brahim Sabour Abstract In the Lake Oued Mellah cyanobacteria waterblooms occur periodically in late spring and summer with Microcystis ichthyoblabe as the main bloom-forming species. In 1999, a heavy waterbloom of M. ichthyoblabe occurred during May June with a maximal biomass of 298 mg/l. During this period, several bloom samples were collected. The toxicity assessment was done by mouse and brine shrimp (Artemia) bioassays. Apart from the sample collected on 15/06/1999, all the other samples were toxic by mouse bioassay. The LD50 determined by intraperitoneal injection to mice during active cyanobacterial growth and decline phases were 518 and 1924 mgDW/kg respectively. Using Artemia bioassay, the 24hLC50 varied from 6.0 to 40.6 mg/ml and the 48hLC50 ranged from 2.8 to 18.2 mg/ml. The separation and identification of microcystin variants was performed by high performance liquid chromatography,photodiode array detection. Eleven toxins were separated and preliminarily identified as microcystin variants as they exhibit a typical UV spectra like the microcystin-LR standard. The quantification of total microcystins determined by enzyme-linked immunosorbent assay showed that the contents were varied between 0.1 and 0.76 ,g/g DW. © 2002 by Wiley Periodicals, Inc. Environ Toxicol 17: 24,31, 2002 [source] Detection and quantification of microcystins from cyanobacteria strains isolated from reservoirs and ponds in MoroccoENVIRONMENTAL TOXICOLOGY, Issue 1 2002B. Oudra Abstract In Morocco, the occurrence of toxic cyanobacteria blooms is confirmed in some water bodies used for recreational and/or as drinking water reservoirs. According to WHO recommendations, the establishment of a monitoring program for microcystins is a necessity. This paper presents toxicological studies of 19 toxic cyanobacteria strains of Microcystis, Synechocystis, Pseudanabaena, and Oscillatoria. These strains were isolated from various water bodies including natural lakes, reservoirs, and ponds located in central regions of Morocco. The isolation, culture, and biomass production of these strains was made on Z8 or BG13 media under laboratory controlled conditions. The hepatotoxicity of cyanobacterial lyophilized material was confirmed by mouse bioassays. The amount of microcystins produced by each strain was determined by the enzyme-linked immunosorbent assay (ELISA). The detection and identification of microcystin variants was performed by high performance liquid chromatography (HPLC) with photodiode array detection. Almost all strains showed medium to high toxicity, the estimated LD50 i.p mice bioassay ranged between 28 to 350 mg/kg body weight. The concentrations of microcystins varied between 2.16 to 944 ,g/g and 26.8 to 1884 ,g/g dry weight determined by ELISA and HPLC, respectively. The screening of bloom-forming and microcystin producer cyanobacteria strains in these fresh water bodies leads us to propose the need for the establishment of a survey of cyanobacteria and a cyanotoxin-monitoring program. © 2002 by Wiley Periodicals, Inc. Environ Toxicol 17: 32,39, 2002 [source] Occurrence and fate of micropollutants in the Vidy Bay of Lake Geneva, Switzerland.ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2010Part II: Micropollutant removal between wastewater, raw drinking water Abstract The occurrence and removal of 58 pharmaceuticals, endocrine disruptors, corrosion inhibitors, biocides, and pesticides, were assessed in the wastewater treatment plant (WWTP) of the city of Lausanne, Switzerland, as well as in the effluent-receiving water body, the Vidy Bay of Lake Geneva. An analytical screening method to simultaneously measure all of the 58 micropollutants was developed based on ultra performance liquid chromatography coupled to a tandem mass spectrometer (UPLC-MS/MS). The selection of pharmaceuticals was primarily based on a prioritization study, which designated them as environmentally relevant for the Lake Geneva region. Except for the endocrine disruptor 17,-ethinylestradiol, all substances were detected in 24-h composite samples of wastewater entering the WWTP or in the treated effluent. Of these compounds, 40% were also detected in raw drinking water, pumped from the lake 3,km downstream of the WWTP. The contributions of dilution and degradation to micropollutant elimination between the WWTP outlet and the raw drinking water intake were established in different model scenarios using hypothetical residence times of the wastewater in Vidy Bay of 1, 4, or 90 d. Concentration decrease due to processes other than dilution was observed for diclofenac, beta-blockers, several antibiotics, corrosion inhibitors, and pesticides. Measured environmental concentrations (MECs) of pharmaceuticals were compared to the predicted environmental concentrations (PECs) determined in the prioritization study and agreed within one order of magnitude, but MECs were typically greater than the corresponding PECs. Predicted no-effect concentrations of the analgesic paracetamol, and the two antibiotics ciprofloxacin and sulfamethoxazole, were exceeded in raw drinking water samples and therefore present a potential risk to the ecosystem. Environ. Toxicol. Chem. 2010; 29:1658,1668. © 2010 SETAC [source] Vigabatrin extracellular pharmacokinetics and concurrent ,-aminobutyric acid neurotransmitter effects in rat frontal cortex and hippocampus using microdialysisEPILEPSIA, Issue 2 2009Xin Tong Summary Purpose:, To investigate the pharmacokinetic interrelationship of vigabatrin in blood and the brain (frontal cortex vs. hippocampus) and to ascertain the relationship between brain extracellular vigabatrin concentrations and concurrent ,-aminobutyric acid (GABA) concentrations. Methods:, Sprague-Dawley rats were implanted with a jugular vein catheter for blood sampling, and microdialysis probes in the frontal cortex and hippocampus for extracellular fluid (ECF) sampling. Vigabatrin was administered intraperitoneally at two different doses (500 and 1,000 mg/kg), and blood and ECF were collected at timed intervals up to 8 h. Rats were freely moving and behaving. Vigabatrin (sera and ECF) and GABA (ECF) concentrations were measured with use of high performance liquid chromatography (HPLC). Results:, Vigabatrin concentrations in blood rose linearly and dose-dependently, and vigabatrin rapidly appeared in the brain as evidenced by the detection of vigabatrin in the ECF of both the frontal cortex and hippocampus at time of first sampling (15 min). However, frontal cortex concentrations were twofold greater than those of the hippocampus. Furthermore, GABA concentrations increased five-fold in the frontal cortex but were unaffected in the hippocampus. In addition, GABA concentrations began to increase approximately 3 h after vigabatrin administration at a time when vigabatrin concentrations were in exponential decline. Conclusions:, Vigabatrin distribution in the brain is region specific, with frontal cortex concentrations substantially greater than those seen in the hippocampus. Elevation of GABA concentrations did not reflect the concentration profile of vigabatrin but reflected its regional distribution. [source] Concentration of methylprednisolone in the centrodistal joint after administration of methylprednisolone acetate in the tarsometatarsal jointEQUINE VETERINARY JOURNAL, Issue 2 2005A. SERENA Summary Reasons for performing study: The centrodistal (CD) and tarsometatarsal (TMT) joints are often injected individually with a corticosteroid to resolve lameness caused by osteoarthritis (OA). There are no data available regarding diffusion of methylprednisolone (MP) from the TMT joint to the CD joint. Hypothesis: A therapeutic concentration of MP diffuses into the CD joint after methylprednisolone acetate (MPA) is administered into the TMT joint. Objective: To measure the concentration of MP in the CD joint after MPA was administered into the TMT joint. Methods: MPA was administered into a TMT joint of 16 horses. At different times, the ipsilateral CD joint of these horses was injected with a small amount of saline and recovered saline was measured for concentration of MP using high performance liquid chromatography. Results: Six hours after administration of MPA into the TMT joint, a therapeutic concentration of MP was found in all 10 CD joints sampled at this time. Conclusions: Horses with pain arising from the distal 2 joints of the hock can be treated by administering MPA into the TMT joint alone. Potential relevance: Administering MPA into the TMT joint only, to treat OA of the distal 2 hock joints, reduces the difficulties and risks associated with centesis of the CD joint. [source] Genetic influence in antithrombotic actions of atorvastatin in hypercholesterolaemiaEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 1 2008L. Puccetti ABSTRACT Background, Recent data indicate that statins could offer coronary artery disease (CAD) benefit even by mechanisms beyond lipid lowering. Genetic influence has been shown for some antithrombotic actions of statins via oxidized-low-density lipoprotein cholesterol (ox-LDL) receptors and nitric oxide synthase (NOS) activity modulation. The present study was designed to evaluate the influence of ox-LDL lectin-like receptor-1 (LOX-1) and NOS polymorphisms in the incidence of cardiovascular events in pure hypercholesterolaemic subjects during statin treatment. Materials and methods, A prospective 4-year study involving 1039 event-free subjects (643 males, 396 females) treated with atorvastatin (10,40 mg day,1) to reach the appropriate Adult Treatment Panel-III LDL target of 3·36 mmol L,1. Enrolled subjects were evaluated every 6 months or at a clinical event. LOX-1 3,UTR/T-C and NOS G894T polymorphisms were detected by allelic discrimination assays (polymerase chain reaction), lipid profile by enzymatic-colorimetric method, ox-LDL by enzyme linked immunosorbent assay, platelet activation by P-selectin (P-sel) expression (FACScan), NOS activity (by intracellular citrullin recovery) and homocysteine (high performance liquid chromatography), C-reactive protein (CRP) by sensitive nephelometric technique. Results, LOX-1 3,UTR/T showed the strongest association with events in the whole cohort with respect to each other variable including LDL reduction and NOS G894T (OR 4·90, 95% CI 3·19,6·98, P < 0·00001). Smoking influenced events in LDL-targeted subjects (P < 0·0001). Ox-LDL and P-sel were better indicators than LDL or other variables according to 3,UTR/C genotype regardless of the magnitude of LDL reduction (OR 4·21, 95% CI 2·29,6·70 P < 0·0001). Conclusions, LOX-1 polymorphisms could influence statin effectiveness in CAD prevention by induction of sensitivity to antithrombotic mechanisms such as antiplatelet activity. [source] Elective coronary angioplasty with 60 s balloon inflation does not cause peroxidative injuryEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 3 2002K. Cedro Abstract Background The aim of this study was to evaluate the ongoing controversial issue of whether ischemia/reperfusion during elective coronary angioplasty evokes myocardial peroxidative injury. Design We measured indicators of free radical damage to lipids (free malondialdehyde) and proteins (sulphydryl groups) in coronary sinus blood in 19 patients with stable angina who were undergoing elective angioplasty for isolated stenosis of the proximal left anterior descending coronary artery. Ischemia induced by 60 s balloon inflations was confirmed by lactate washout into coronary sinus after deflation, with immediate and 1 min samples. Peroxidative injury was assessed from washout of (a) malondialdehyde measured directly by high performance liquid chromatography and (b) reduced sulphydryl groups, inverse marker of protein oxidative stress. Results Mean lactate concentration immediately after each deflation increased by 120,150% of the initial value, confirming ischemia and showing that blood originated largely from the ischemic region. Lack of myocardial production of malondialdehyde was confirmed by (a) no arteriovenous differences in individual basal concentrations (aortic, range 0·33,12·03 nmol mL,1, mean 7·82; coronary sinus blood, range 0·52,15·82 nmol mL,1, mean 8·18), and (b) after deflations, mean concentrations were not significantly different from preocclusion value. There was no decrease in concentration of sulphydryl groups throughout angioplasty. Conclusion Elective coronary angioplasty with 60 s balloon inflations is a safe procedure that does not induce peroxidative myocardial injury as assessed by methods used in the present study. [source] Effects of rapamycin on accumulation of , -, , - and , -globin mRNAs in erythroid precursor cells from , -thalassaemia patientsEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2006Eitan Fibach Abstract:, We studied the effects of rapamycin on cultures of erythroid progenitors derived from the peripheral blood of 10 , -thalassaemia patients differing widely with respect to their potential to produce foetal haemoglobin (HbF). For this, we employed the two-phase liquid culture procedure for growing erythroid progenitors, high performance liquid chromatography for analysis of HbF production and reverse transcription polymerase chain reaction for quantification of the accumulation of globin mRNAs. The results demonstrated that rapamycin induced an increase of HbF in cultures from all the , -thalassaemia patients studied and an increase of their overall Hb content/cell. The inducing effect of rapamycin was restricted to , -globin mRNA accumulation, being only minor for , -globin and none for , -globin mRNAs. The ability of rapamycin to preferentially increase , -globin mRNA content and production of HbF in erythroid precursor cells from , -thalassaemia patients is of great importance as this agent (also known as sirolimus or rapamune) is already in clinical use as an anti-rejection agent following kidney transplantation. These data suggest that rapamycin warrants further evaluation as a potential therapeutic drug in , -thalassaemia and sickle cell anaemia. [source] Solvolysis of Some Arenediazonium Salts in Binary EtOH/H2O Mixtures under Acidic ConditionsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 17 2003Román Pazo-Llorente Abstract We have determined the product distribution, the rate constants for dediazoniation product formation, and the solvolytic rate constants for 2-, 3-, and 4-methylbenzenediazonium ions (2-, 3-, and 4-MBD, respectively) loss in acidic ethanol/water mixtures over the whole composition range by a combination of spectrophotometric (UV/Vis) and high performance liquid chromatography (HPLC) measurements. The observed rate constants (kobs) for substrate loss are equal to those for product formation, and they remain essentially constant (2-MBD) with changing solvent composition but increase by a factor of ,2 (4MBD) on going from water to 100% EtOH. Up to four dediazoniation products , cresols (ArOH), chlorotoluene (ArCl), methylphenetole (ArOEt), and toluene (ArH) , were detected, depending on the solvent composition; the major dediazoniation products were the ArOH and ArOEt derivatives. The product selectivity (S) of the reaction towards nucleophiles is low and essentially constant with changing solvent composition, and good linear correlations between log kobs and YCl (solvent ionizing power) were observed for the three ArN2+ ions. All data are consistent with the rate-determining formation of an aryl cation, which reacts immediately with available nucleophiles. The data suggest that the distribution of neutral and anionic nucleophiles in the neighborhood of the ground state arenediazonium ion remains essentially unchanged upon dediazoniation, the observed product distribution reflecting the concentrations of nucleophiles in their immediate environment (i.e., in the first solvation shells of the arenediazonium ions). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Screening of urocanic acid isomers in human basal and squamous cell carcinoma tumors compared with tumor periphery and healthy skinEXPERIMENTAL DERMATOLOGY, Issue 10 2008Juan Manuel Decara Abstract:,Trans -urocanic acid is a major chromophore for ultraviolet (UV) radiation in human epidermis. The UV induces photoisomerization of trans -urocanic acid (tUCA) form to cis -urocanic acid (cUCA) and has been reported as an important mediator in the immunosuppression induced by UV. This immunomodulation has been recognized as an important factor related to skin cancer development. This is the first time that UCA isomers have been measured in epidermis of skin biopsies from patients with squamous cell carcinoma (SCC) and with basal cell carcinoma (BCC) and compared with the tumor periphery and biopsies of healthy photoexposed and non-photoexposed skin as controls. The UCA isomers were separated and quantified by high performance liquid chromatography. Analysis of UCA in healthy skin showed significant increase in total UCA content in non-photoexposed body sites compared with highly exposed skins. In contrast, the percentage of cUCA was higher in photoexposed body sites. Maximal levels of cUCA were found in cheek, forehead and forearm and lower levels in abdomen and thigh. No differences were found in total UCA concentration between the tumor samples and healthy photoexposed skin. However, differences were found in relation between isomers. Higher levels of cUCA were detected in SCC biopsies (44% of total UCA) compared with samples of BCC and that of healthy photoexposed skin (30%). These results suggest that the UV radiation exposure, a main factor in development of SCC can be mediated, apart from direct effect to cells (DNA damage), by immunosuppression pathways mediated by high production of cUCA. [source] Identification of proNeuropeptide FFA peptides processed in neuronal and non-neuronal cells and in nervous tissueFEBS JOURNAL, Issue 20 2003Elisabeth Bonnard Peptides which should be generated from the neuropeptide FF (NPFF) precursor were identified in a neuronal (human neuroblastoma SH-SY5Y) cell line and in COS-7 cells after transient transfection of the human proNPFFA cDNA and were compared with those detected in the mouse spinal cord. After reverse-phase high performance liquid chromatography of soluble material, NPFF-related peptides were immunodetected with antisera raised against NPFF and identified by using on-line capillary liquid chromatography/nanospray ion trap tandem mass spectrometry. Neuronal and non-neuronal cells generated different peptides from the same precursor. In addition to NPFF, SQA-NPFF (Ser-Gln-Ala-Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-amide) and NPAF were identified in the human neuroblastoma while only NPFF was clearly identified in COS-7 cells. In mouse, in addition to previously detected NPFF and NPSF, SPA-NPFF (Ser-Pro-Ala-Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-amide), the homologous peptide of SQA-NPFF, were characterized. These data on intracellular processing of proNeuropeptide FFA are discussed in regard to the known enzymatic processing mechanisms. [source] Adhesion and development of the root rot fungus (Heterobasidion annosum) on conifer tissues: effects of spore and host surface constituentsFEMS MICROBIOLOGY ECOLOGY, Issue 2 2000Frederick O Asiegbu Abstract The objective of this study was to correlate the occurrence of particular root and woody stump surface components with the ability of spores of the root rot fungus (Heterobasidion annosum) to adhere, germinate and establish on conifer tissues. With the aid of high performance liquid chromatography, several sugars (pinitol, xylitol, dulcitol, mannitol, D -glucose, mannose, fructose) were detected on both stump and fine root surfaces of Scots pine and Norway spruce. Of all the sugars observed, xylose and arabinose were poorly utilized for initiation of germ tube growth whereas spore germination was enhanced in the presence of D -glucose, mannose or fructose. Oxidation of these sugars by pretreatment of wood discs or roots with periodic acid abolished the ability of the spores to germinate. Non-sugar components such as long chain fatty acids on spores and root surfaces as detected with nuclear magnetic resonance were found to have a significant influence on adhesion and initiation of germ tube development. Removal of these aliphatic compounds from the root surface increased spore germination by 2-fold, whereas similar treatment on spores led to a 5-fold decrease in adhesiveness to root material. In vitro studies revealed that the di-ethyl ether extract from the roots had no long term adverse effect on spore germination which suggests that the fungus may possess the capability to detoxify this substance. Similarly, adhesion of spores was affected by low and freezing temperatures. The role of significant levels of mannitol and trehalose accumulated in spores and hyphae of the fungi on viability, survival and tolerance to adverse conditions such as oxidative stress, freezing and desiccation are discussed. [source] Identification of Trichoderma strains by image analysis of HPLC chromatogramsFEMS MICROBIOLOGY LETTERS, Issue 2 2001Ulf Thrane Abstract Forty-four Trichoderma strains from water-damaged building materials or indoor dust were classified with chromatographic image analysis on full chromatographic matrices obtained by high performance liquid chromatography with UV detection of culture extracts. The classes were compared with morphological identification and rDNA sequence data, and for each class all strains were of the same identity. With all three techniques each strain , except one , was identified as the same species. These strains belonged to Trichoderma atroviride (nine strains), Trichoderma viride (three strains), Trichoderma harzianum (10 strains), Trichoderma citrinoviride (12 strains), and Trichoderma longibrachiatum (nine strains). The odd strain was identified as Trichoderma hamatum by morphology and rDNA sequencing, but not by image analysis as no reference strains of this species were included. It is concluded that the secondary metabolite profile contains sufficient information for classification and species identification. [source] Biotransformation in vitro of the 22R and 22S epimers of budesonide by human liver, bronchus, colonic mucosa and skinFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 1 2001Julio Cortijo The pharmacological effects of glucocorticoids are greatly influenced by their pharmacokinetic properties. In the present report, the in vitro biotransformation of the 22R and 22S epimers of the topical steroid budesonide was studied in the S-9 fraction of human liver, bronchus, skin and colonic mucosa. The disappearance of unchanged epimers of budesonide was measured during 90 min of incubation by high performance liquid chromatography. The rate of disappearance was high in human liver while little biotransformation occurred in bronchial tissue and colonic mucosa, and none was detected in the skin. A marked decay of the initial concentration of unchanged budesonide epimers was noticed after 2 h incubation in cultured human hepatocytes, while only a small decrease was observed after 24 h incubation in cultured human airway smooth muscle cells and BEAS-2B cells. The 22R epimer of budesonide suffered greater in vitro biotransformation than the 22S epimer in human hepatic, bronchial and colonic tissues. These findings extend those of other studies, and confirm that the high therapeutic ratio of budesonide is due to negligible local biotransformation combined with high level of liver metabolism for locally absorbed budesonide. [source] ORIGINAL ARTICLE Laboratory science: Spectrum of F8 gene mutations in haemophilia A patients from a region of Italy: identification of 23 new mutationsHAEMOPHILIA, Issue 5 2010F. RICCARDI Summary., Haemophilia A (HA) is an X-linked recessive bleeding disorder caused by a lack or decrease of coagulation factor VIII activity. The molecular diagnosis of HA is challenging and a variety of different mutations have been identified throughout the F8 gene. Our aim was to detect the causative mutation in 266 HA patients from Emilia-Romagna region (Italy) and in all suspected carriers. Molecular analysis of F8 in 201 HA patients (152 index cases) was performed with a combination of several indirect and direct molecular approaches, such as long distance polymerase chain reaction, multiplex ligation-dependent probe amplification, denaturing high performance liquid chromatography and direct sequencing. The analysis revealed 78 different mutations, 23 of which were novel, not having been reported in national or international databases. The detection rate was 100%, 86% and 89% in patients with severe, moderate and mild HA, respectively. The information provided by this registry will be helpful for monitoring the treatment of HA patients in Emilia-Romagna and also for reliable genetic counselling of affected families in the future. [source] Clinical benefit of interventions driven by therapeutic drug monitoringHIV MEDICINE, Issue 5 2005AL Rendón Background Adequate plasma concentrations of antiretroviral drugs are key to achieving and maintaining long-term suppression of HIV replication. Multiple factors may influence drug levels, causing increases or reductions that may, respectively, result in toxicity or virological failure. Therapeutic drug monitoring (TDM) might help to detect and correct such abnormalities. Objective To evaluate the usefulness of TDM in the care of HIV-infected patients in an out-patient clinical setting. Methods All the requests for TDM of protease inhibitors (PIs) and nonnucleoside reverse transcriptase inhibitors (NNRTIs) for patients attending our HIV out-patient clinic from October 2000 to August 2003 were analysed. Blood samples were collected before the morning dose. Drug concentrations were measured by high performance liquid chromatography by ultraviolet waves (HPLC-UV). Results A total of 151 requests from 137 patients were assessed. The reasons for requesting TDM were drug toxicity (59%), virological failure (39%) and possible drug interactions (2%). NNRTI levels were more often requested because of toxicity, while PI levels were more often requested because of virological failure. Elevated drug levels were confirmed in 36% of patients with suspected drug toxicity, while subtherapeutic levels were found in 37% of patients failing virologically. Based on the results of TDM, dose modifications were made in 37% of patients, allowing correction of such abnormalities in 80% of cases. Moreover, adequate plasma concentrations were confirmed in 79% of patients whose levels were assessed again. Conclusions Therapeutic drug monitoring may be a useful tool to identify toxic levels of NNRTI and subtherapeutic concentrations of PI. Dose adjustments following TDM may ameliorate drug-related toxicities or improve virological response rates. [source] The level of polyaromatic hydrocarbons in kajal and surma of major Indian brandsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 3 2009D. K. Patel Synopsis Kajal and surma are eye cosmetics extensively used in Indian subcontinent. Kajal is prepared by burning of vegetable oil and butter oil while surma by grinding of the stones. High performance liquid chromatography and gas chromatography,mass spectrometry instruments were used for quantification and confirmation of 16 polyaromatic hydrocarbons (PAHs). Significant concentration of PAH was found in all the samples examined. The median concentration of PAH ranged from 0.14 (lowest, anthracene) to 31.18 ,g g,1 [dibenz(a,h)anthracene] in kajal sample and from not detectable concentration (naphthalene) to 197.47 ,g g,1 of benzo(a)pyrene in surma sample. Fifteen PAHs were detected in all the samples. Therefore the use of kajal and surma in eye should be strictly restricted. Résumé Le Kajal et le Surma sont des composés très utilisés sur le sous-continent indien pour le maquillage des yeux. Ils sont préparés par calcination d'huile végétale et d'huile de beurre, puis par broyage des résidus. La chromatographie liquide haute pression et la chromatographie en phase gazeuse couplée à la spectrométrie de masse ont été employées pour quantifier et valider seize hydrocarbures polyaromatiques (PAHs). Des concentrations significatives en PAHs ont été trouvées dans les échantillons examinés. La concentration médiane en PAH classées de la faible à la plus élevée est de 0,14 ,g g,1 (anthracène) à 31,18 ,g g,1 (dibenz (a,h) anthracène) dans l'échantillon de Kajal et d'une présence ND (naphtalène) à 197,47 ,g g,1 (benzo (a) pyrène) dans l'échantillon de Surma. Quinze PAHs ont été détectés dans tous les échantillons. En conséquence, l'utilisation de Kajal et de Surma pour la cosmétique des yeux doit être limitée de façon stricte. 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