Publications by authors named "Paul Fawcett"

Article Synopsis
  • The skeletal dysplasias are a diverse group of genetic conditions impacting bone and cartilage growth, but the role of cytokines in these disorders is not well understood.
  • A study analyzed cytokine levels in 136 children with skeletal dysplasia compared to 275 healthy controls, focusing on 12 specific cytokines across various dysplasia types.
  • Findings revealed significant differences in cytokine expression, with certain cytokines consistently elevated or decreased across all dysplasia cohorts, highlighting particularly high levels in MOPDII cases.
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Unlabelled: BACKGROUND AND OBJECTIVE: Postmenopausal women often require estrogen supplementation to improve menopausal and postmenopausal vasomotor symptoms and maintain hormonal balance. Conjugated equine estrogens extracted from the urine of pregnant mares are commonly used to provide this estrogen replacement therapy. The complex composition of this mixture of animal sulfated metabolites makes its bioanalysis challenging such that its detailed pharmacokinetics has not been fully characterized.

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d--Tocopheryl polyethylene glycol 1000 succinate (TPGS, also known as vitamin E-TPGS) is a biodegradable amphiphilic polymer prepared by esterification of vitamin E with polyethylene glycol (PEG) 1000. It is approved by the US Food and Drug Administration (FDA) and has found wide application in nanocarrier drug delivery systems (NDDS). Fully characterizing the fate and pharmacokinetic behavior of TPGS is important to promote the further development of TPGS-based NDDS.

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Objectives: Ketotifen (K) and its active metabolite norketotifen (N) exist as optically active atropisomers. They both have antihistaminic and anti-inflammatory properties but the S-atropisomer of N (SN) causes less sedation than K and RN in rodents. This study investigated whether this could be related to a lower concentration of SN in brain or a lower affinity of SN for rat brain H receptors.

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The PEGylated liposomal nanoparticle has been widely used as a carrier in drug delivery system. To become biologically active, the encapsulated drug must be released from the nanoparticle vehicle. However, due to limitations of current bioanalytical methods, the characterization of this release process has been restricted to determination of total drug in tissues and tumor.

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Therapeutic drug monitoring (TDM) is necessary in the clinical management of linezolid to improve its efficacy and reduce the risk of time- and dose-dependent toxicity. A novel and ultrahigh-throughput analytical method for the determination of linezolid in human plasma was developed based on direct analysis in real-time tandem mass spectrometry (DART-MS/MS) without chromatographic separation. After solid-phase extraction with Waters Oasis HLB, the linezolid and internal standard linezolid-d were detected by positive ion electrospray ionization followed by multiple reaction monitoring (MRM) of the transition at m/z 338.

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Because many therapeutic agents are contaminated by epimeric impurities or form epimers as a result of metabolism, analytical tools capable of determining epimers are increasingly in demand. This article is a proof-of-principle report of a novel DMS-MS/MS method to separate and simultaneously quantify epimers, taking PGF2 and its 8-epimer, 8--PGF2, as an example. Good accuracy and precision were achieved in the range of 10-500 ng/mL with a run time of only 1.

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Pulmonary hypertension in the neonate requires treatment with oxygen and positive pressure ventilation, both known to induce lung injury. The direct response of pulmonary artery smooth muscle cells, the most abundant cells in the artery wall, to the stress of positive pressure and hyperoxia has not been previously studied. Pulmonary artery smooth muscle cells were cultured in temperature- and pressure-controlled air-tight chambers under conditions of positive pressure or hyperoxia for 24 h.

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Page 1789, table 1, 'Carmoterol' row: The cell entry in the 'Stereochemistry' column, which previously read.

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Eptifibatide is a therapeutic cyclic peptide with poor collision-induced dissociation (CID) efficiency for multiple reaction monitoring (MRM), which limits the development of a traditional liquid chromatography-tandem mass spectrometry (LC-MS/MS) bioassay with MRM. In this study, a method combining differential mobility spectrometry (DMS) with liquid chromatography-multiple ion monitoring (LC-DMS-MIM) was developed for the quantitation of eptifibatide in rat plasma. After solid phase extraction (SPE) of 100 μL plasma on an Oasis HLB cartridge, the analyte and I.

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The covalent attachment of polyethylene glycol (PEG) to therapeutic compounds (known as PEGylation) is one of the most promising techniques to improve the biological efficacy of small molecular weight drugs. After administration, PEGylated prodrugs can be metabolized into pharmacologically active compounds so that PEGylated drug, free drug and released PEG are present simultaneously in the body. Understanding the pharmacokinetic behavior of these three compounds is needed to guide the development of pegylated theranostic agents.

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Rabeprazole is a novel benzimidazole proton pump inhibitor used for the treatment of gastrointestinal disorders. It is a chiral molecule that gives rise to the possibility of stereoselective pharmacokinetics. To investigate this phenomenon, a rapid and sensitive chiral assay based on supercritical fluid chromatography tandem mass spectrometry was developed and applied to the determination of (R)-rabeprazole and (S)-rabeprazole in dog plasma.

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The World Anti-Doping Agency (WADA) currently allows therapeutic use of the beta2-agonists salbutamol, formoterol and salmeterol when delivered via inhalation despite some evidence suggesting these anti-asthma drugs may be performance enhancing. Beta2-agonists are usually administered as 50:50 racemic mixtures of two enantiomers (non-superimposable mirror images), one of which demonstrates significant beta2-adrenoceptor-mediated bronchodilation while the other appears to have little or no pharmacological activity. For salbutamol and formoterol, urine thresholds have been adopted to limit supratherapeutic dosing and to discriminate between inhaled (permitted) and oral (prohibited) use.

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Background: Chromatographic separation of enantiomers is considered a task in analytical chemistry particularly for high sample throughput. This paper describes a high-throughput parallel HPLC-MS/MS method for the determination of pantoprazole enantiomers.

Results: Baseline separation of pantoprazole enantiomers was achieved on a Chiralcel OZ-RH column in a run time of 4.

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A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method using positive/negative electrospray ionization (ESI) switching for the simultaneous quantitation of carboprost methylate and carboprost in dog plasma has been developed and validated. After screening, the esterase inhibitor, dichlorvos was added to the whole blood at a ratio of 1:99 (v/v) to stabilize carboprost methylate during blood collection, sample storage and LLE. Indomethacin was added to plasma to inhibit prostaglandins synthesis after sampling.

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The pentapeptide thymopentin (Arg-Lys-Asp-Val-Tyr, RKDVY) corresponds to amino acids 32-36 of the 49 amino acid immunomodulatory polypeptide, thymopoietin, whose biological activity is partially reproduced. Thymopentin is widely used in the clinic and represents a promising target for drug design but bioanalytical and pharmacokinetic data are limited due to its enzymatic instability. This paper reports a rapid and sensitive method based on liquid chromatography with tandem mass spectrometry for the determination of thymopentin in beagle dog blood.

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The deuterohemin-peptide conjugate (DhHP-6) is a microperoxidase mimetic, which has demonstrated substantial benefits in vivo as a scavenger of reactive oxygen species. This paper reports the development of a sensitive and rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the determination of DhHP-6 in rat plasma using triptorelin as an internal standard (IS). 50μL plasma was used in sample preparation, and a simple protein precipitation procedure with acetonitrile was involved.

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Research has suggested that exposure to sub-micellar concentrations of bile salts (BS) increases the permeability of lipid bilayers in a time-dependent manner. In this study, incubation of soy phosphatidylcholine small unilamellar vesicles (liposomes) with sub-micellar concentrations of cholate (C), deoxycholate (DC), 12-monoketocholate (MKC) or taurocholate (TC) in pH 7.2 buffer increased membrane fluidity and negative zeta potential in the order of increasing BS liposome-pH 7.

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Objective: This study was designed to investigate the pathogenic contributions of fibroblast-like synoviocytes (FLS) to juvenile idiopathic arthritis (JIA) by identifying pathways with dysregulated gene expression in FLS from patients with oligoarticular JIA.

Methods: FLS were derived from synovial fluid obtained by arthrocentesis from patients with JIA undergoing intraarticular steroid injections and from orthopedic control patients. Gene expression profiles of the JIA and control FLS were obtained using the Affymetrix platform, with application of Ingenuity Pathway Analysis and Gene Set Enrichment Analysis software to define gene sets in dysregulated pathways and networks of potential pathologic relevance in this disease.

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Objectives: Radix Gentianae is a traditional Chinese medicine derived from medicinal plants of the family Gentianaceae. Its pharmacological effects have been primarily attributed to the presence of a number of secoiridoid glycosides, in particular gentiopicroside and swertiamarin. In this study, a rapid and sensitive method based on ultrafast liquid chromatography-tandem mass spectrometry has been developed for the simultaneous determination of gentiopicroside and swertiamarin in rat plasma using paeoniflorin as internal standard (IS).

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Aralia mandshrica is a well-known traditional Chinese medicine from Northeast China commonly used to treat digestive, circulatory and immune system disorders. Calenduloside E is one of its bioactive components currently under evaluation as a pure drug. In this study, a highly sensitive and rapid method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous quantitation of calenduloside E and its active metabolite oleanolic acid in beagle dog plasma has been developed and validated.

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Ethnopharmacological Relevance: Adequate pharmacokinetic data of escin, a natural mixture of triterpene saponins used for the treatment of chronic venous insufficiency, hemorrhoids, inflammation and edema, is of special interest in view of the growing use of escin agent in clinical medicine. However, pharmacokinetic data are inadequate to support their clinical indication. Escin Ib and isoescin Ib are the chief active ingredients in escin, pharmacokinetics study of them would be helpful for improving the practice of escin application.

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O-Desmethylvenlafaxine (desvenlafaxine, ODV) is a recently approved antidepressant which in some clinical studies failed to meet a satisfactory end-point. The aim of this study was to prepare a series of phenolic esters of ODV and evaluate their potential as ODV prodrugs with improved brain uptake. Fifteen phenolic esters (compounds 1a-o) were synthesized and their pharmacokinetic profiles evaluated in rat.

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High throughput transmission electron microscopy (TEM) is limited by the time that it takes to prepare each specimen and insert it on the microscope. It is further impeded by the deteriorating vacuum of the microscope upon frequent specimen cycling. Nevertheless, in most cases only a small fraction of the specimen is examined and sufficient to provide hundreds of images.

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A rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the simultaneous quantitation of five major active ingredients of Ixeris sonchifolia (Bge.) Hance in rat plasma has been developed and validated. After liquid-liquid extraction of 50μL plasma with ethyl acetate, analytes and internal standard (I.

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