Search results for: David G. Watson

Items from 1 to 20 out of 58 results

article

Effects of Nigerian red propolis in rats infected with Trypanosoma brucei brucei

Nwakaego E. Nweze, Henry O. Okoro, Majed Al Robaian, Ruwida M. K. Omar, more

Comparative Clinical Pathology > 2017 > 26 > 5 > 1129-1133

Propolis has a long history of use in folk medicine and possesses various biological activities. Effects of the methanol extract of Nigerian red propolis (NRP) in trypanosome-infected rats were studied. Mature albino Wistar rats (30) were randomly grouped into six (A–F). Groups A–E were infected with 1.0 × 10⁶Trypanosoma brucei brucei organisms intraperitoneally. Group F was uninfected. On establishment...

article

A method for the analysis of sugars in biological systems using reductive amination in combination with hydrophilic interaction chromatography and high resolution mass spectrometry

Sami Bawazeer, Ali Muhsen Ali, Aliyah Alhawiti, Abedawn Khalaf, more

Talanta > 2017 > 166 > C > 75-80

Separation of sugar isomers extracted from biological samples is challenging because of their natural occurrence as alpha and beta anomers and, in the case of hexoses, in their pyranose and furanose forms. A reductive amination method was developed for the tagging of sugars with the aim of it becoming part of a metabolomics work flow. The best separation of the common hexoses (glucose, fructose, mannose...

article

Effect of the sphingosine kinase 1 selective inhibitor, PF-543 on arterial and cardiac remodelling in a hypoxic model of pulmonary arterial hypertension

Neil MacRitchie, Giora Volpert, Mohammed Al Washih, David G. Watson, more

Cellular Signalling > 2016 > 28 > 8 > 946-955

Recent studies have demonstrated that the expression of sphingosine kinase 1, the enzyme that catalyses formation of the bioactive lipid, sphingosine 1-phosphate, is increased in lungs from patients with pulmonary arterial hypertension. In addition, Sk1^−/− mice are protected from hypoxic-induced pulmonary arterial hypertension. Therefore, we assessed the effect of the sphingosine kinase 1 selective...

article

An evaluation of Minor Groove Binders as anti-lung cancer therapeutics

Fraser J. Scott, Mireia Puig-Sellart, Abedawn I. Khalaf, Catherine J. Henderson, more

Bioorganic & Medicinal Chemistry Letters > 2016 > 26 > 15 > 3478-3486

A series of 47 structurally diverse MGBs, derived from the natural product distamycin, was evaluated for anti-lung cancer activity by screening against the melanoma cancer cell line B16-F10. Five compounds have been found to possess significant activity, more so than a standard therapy, Gemcitabine. Moreover, one compound has been found to have an activity around 70-fold that of Gemcitabine and has...

article

Evaluation of the technical variations and the suitability of a hydrophilic interaction liquid chromatography-high resolution mass spectrometry (ZIC-pHILIC-Exactive orbitrap) for clinical urinary metabolomics study

Tong Zhang, David G. Watson

Journal of Chromatography B > 2016 > 1022 > C > 199-205

Although many hydrophilic interaction liquid chromatography-high resolution mass spectrometry (HILIC-HRMS) methods have been developed and applied for untargeted metabolite profiling in clinical metabolomics, according to the literature, the suitability of these HILIC-HRMS methods has not been fully evaluated with respect to their performance when they are subjected to statistical analysis. In this...

article

Chemical characterisation of Nigerian red propolis and its biological activity against Trypanosoma Brucei

Ruwida M. K. Omar, John Igoli, Alexander I. Gray, Godwin Unekwuojo Ebiloma, more

Phytochemical Analysis > 27 > 2 > 107 - 115

IntroductionA previous study showed the unique character of Nigerian red propolis from Rivers State, Nigeria (RSN), with regards to chemical composition and activity against Trypanosoma brucei in comparison with other African propolis. ObjectiveTo carry out fractionation and biological testing of Nigerian propolis in order to isolate compounds with anti‐trypanosomal activity. To compare the composition...

article

Fenretinide mediated retinoic acid receptor signalling and inhibition of ceramide biosynthesis regulates adipogenesis, lipid accumulation, mitochondrial function and nutrient stress signalling in adipocytes and adipose tissue

George D. Mcilroy, Seshu R. Tammireddy, Benjamin H. Maskrey, Louise Grant, more

Biochemical Pharmacology > 2016 > 100 > C > 86-97

Fenretinide (FEN) is a synthetic retinoid that inhibits obesity and insulin resistance in high-fat diet (HFD)-fed mice and completely prevents 3T3-L1 pre-adipocyte differentiation. The aim of this study was to determine the mechanism(s) of FEN action in 3T3-L1 adipocytes and in mice. We used the 3T3-L1 model of adipogenesis, fully differentiated 3T3-L1 adipocytes and adipose tissue from HFD-induced...

article

Polymeric Nanoparticles of Brazilian Red Propolis Extract: Preparation, Characterization, Antioxidant and Leishmanicidal Activity

Ticiano Gomes do Nascimento, Priscilla Fonseca da Silva, Lais Farias Azevedo, Louisianny Guerra da Rocha, more

Nanoscale Research Letters > 2016 > 11 > 1 > 1-16

The ever-increasing demand for natural products and biotechnology derived from bees and ultra-modernization of various analytical devices has facilitated the rational and planned development of biotechnology products with a focus on human health to treat chronic and neglected diseases. The aim of the present study was to prepare and characterize polymeric nanoparticles loaded with Brazilian red propolis...

article

Metabolomic Profiling of Post-Mortem Brain Reveals Changes in Amino Acid and Glucose Metabolism in Mental Illness Compared with Controls

Rong Zhang, Tong Zhang, Ali Muhsen Ali, Mohammed Al Washih, more

Computational and Structural Biotechnology Journal > 2016 > 14 > C > 106-116

Metabolomic profiling was carried out on 53 post-mortem brain samples from subjects diagnosed with schizophrenia, depression, bipolar disorder (SDB), diabetes, and controls. Chromatography on a ZICpHILIC column was used with detection by Orbitrap mass spectrometry. Data extraction was carried out with m/z Mine 2.14 with metabolite searching against an in-house database. There was no clear discrimination...

article

Improving arteriovenous fistula patency: Transdermal delivery of diclofenac reduces cannulation-dependent neointimal hyperplasia via AMPK activation

Mark G. MacAskill, David G. Watson, Marie-Ann Ewart, Roger Wadsworth, more

Vascular Pharmacology > 2015 > 71 > C > 108-115

Creation of an autologous arteriovenous fistula (AVF) for vascular access in haemodialysis is the modality of choice. However neointimal hyperplasia and loss of the luminal compartment result in AVF patency rates of ~60% at 12months. The exact cause of neointimal hyperplasia in the AVF is poorly understood. Vascular trauma has long been associated with hyperplasia. With this in mind in our rabbit...

article

An LCMS method for the assay of melittin in cosmetic formulations containing bee venom

Jonans Tusiimire, Jennifer Wallace, Mark Dufton, John Parkinson, more

Analytical and Bioanalytical Chemistry > 2015 > 407 > 13 > 3627-3635

There is a growing interest in the potential of bee venom in cosmetics as a rejuvenating agent. Products currently on the market do not specify exactly their content of bee venom (BV). Therefore, we developed a method for the detection and quantification of melittin, as a marker of bee venom content, in selected commercial creams which contained BV according to their marketing claims, in order...

article

Chromatographic and spectroscopic analysis of the components present in the phenanthridinium trypanocidal agent isometamidium

John O. Igoli, Gavin Blackburn, Alexander I. Gray, Oliver B. Sutcliffe, more

Analytical and Bioanalytical Chemistry > 2015 > 407 > 4 > 1171-1180

The chromatographic isolation and characterisation of the four compounds present in the quaternary phenanthridine veterinary trypanocidal agent, isometamidium chloride hydrochloride (ISM), is reported. The isolated compounds were unambiguously characterised using spectroscopic (NMR, UV, IR and MS) methods as 3-amino-8-[3-(3-carbamimidoyl-phenyl)-triazenyl]-5-ethyl-6-phenylethidium (1a) and related...

article

The Isolation of Antiprotozoal Compounds from Libyan Propolis

Weam Siheri, John O. Igoli, Alexander I. Gray, Ticiano G. Nasciemento, more

Phytotherapy Research > 28 > 12 > 1756 - 1760

Propolis is increasingly being explored as a source of biologically active compounds. Until now, there has been no study of Libyan propolis. Two samples were collected in North East Libya and tested for their activity against Trypanosoma brucei. Extracts from both samples had quite high activity. One of the samples was fractionated and yielded a number of active fractions. Three of the active fractions...

article

Isolation of diterpenes and flavonoids from a new type of propolis from Saudi Arabia

Sultan Almutairi, RuAngelie Edrada-Ebel, James Fearnley, John O. Igoli, more

Phytochemistry Letters > 2014 > 10 > Complete > 160-163

The chemical composition and biological activity of a sample of Saudi Arabian propolis were investigated. A new diterpene propsiadin ((ent)-2-oxo-kaur-16-en-6,18-diol) (3) along with the flavonoids 3,4-dihydro-2-(3,4-dihydroxyphenyl)-2H-chromene-3,7-diol (1), psiadiarabin (2) and the diterpene psiadin (4) were isolated from a Saudi Arabian propolis. Their structures were determined by HR-ESI-MS, 1D...

article

New anti-trypanosomal active prenylated compounds from African propolis

Sultan Almutairi, Ben Eapen, Sai Maneesha Chundi, Adnan Akhalil, more

Phytochemistry Letters > 2014 > 10 > Complete > 35-39

The secondary metabolite composition of propolis has always been corroborated on the vegetation surrounding the bee hive. The plants chosen by the bees seem to exhibit activity to protect the hive from the surrounding environmental pressures which include protozoal attack. Two new stilbene compounds were isolated from Ghanian propolis which were formed either via geranylation or prenylation. These...

article

Evaluation of mobile phase characteristics on three zwitterionic columns in hydrophilic interaction liquid chromatography mode for liquid chromatography-high resolution mass spectrometry based untargeted metabolite profiling of Leishmania parasites

Rong Zhang, David G. Watson, Lijie Wang, Gareth D. Westrop, more

Journal of Chromatography A > 2014 > 1362 > C > 168-179

It has been reported that HILIC column chemistry has a great effect on the number of detected metabolites in LC–HRMS-based untargeted metabolite profiling studies. However, no systematic investigation has been carried out with regard to the optimisation of mobile phase characteristics. In this study using 223 metabolite standards, we explored the retention mechanisms on three zwitterionic columns...

article

A Comparison of Silica C and Silica Gel in HILIC Mode: The Effect of Stationary Phase Surface Area

Eman Y. Santali, Darren Edwards, Oliver B. Sutcliffe, Sophie Bailes, more

Chromatographia > 2014 > 77 > 13-14 > 873-881

In order to assess the effect of silica gel structure on retention in hydrophilic interaction chromatography, a test system was developed which used quaternary ammonium ions as probes with tetramethylammonium acetate (TMAA) as the counter-ion competing against the interaction of the test probes with ionised silanols in the stationary phase. Four silica gel columns and a silica hydride column were...

article

Development of a method to measure free and bound ropivacaine in human plasma using equilibrium dialysis and Hydrophilic interaction chromatography coupled to high resolution mass spectrometry

Muhammad Abbas, Lateef Ahmad, Yasar Shah, Mike Gill, more

Talanta > 2013 > 117 > Complete > 60-63

The pharmacodynamics of absorption of local anaesthetics used during surgical procedures into tissues is governed by the amount of free drug in plasma. Toxicity may occur during continuous infusions if the levels of free drug become too high which may occur if the binding capacity of the α-1- acid glycoprotein present in plasma is exceeded. In order to monitor this a method was developed for the determination...

article

The roles of sphingosine kinases 1 and 2 in regulating the Warburg effect in prostate cancer cells

David G. Watson, Francesca Tonelli, Manal Alossaimi, Leon Williamson, more

Cellular Signalling > 2013 > 25 > 4 > 1011-1017

Two isoforms of sphingosine kinase, SK1 and SK2, catalyze the formation of the bioactive lipid sphingosine 1-phosphate (S1P) in mammalian cells. We have previously shown that treatment of androgen-sensitive LNCaP prostate cancer cells with a non-selective SK isoform inhibitor, 2-(p-hydroxyanilino)-4-(p-chlorophenyl)thiazole (SKi), induces the proteasomal degradation of SK1. This is concomitant with...

article

Elucidation of the Phase I and Phase II metabolic pathways of (±)-4′-methylmethcathinone (4-MMC) and (±)-4′-(trifluoromethyl)methcathinone (4-TFMMC) in rat liver hepatocytes using LC–MS and LC–MS2

Osama I.G. Khreit, M. Helen Grant, Tong Zhang, Catherine Henderson, more

Journal of Pharmaceutical and Biomedical Analysis > 2013 > 72 > Complete > 177-185

(±)-4′-Methylmethcathinone hydrochloride [(±)-mephedrone, 4-MMC] is a synthetic “legal high”, with a classical cathinone structure similar to methcathinone. In this study, the in vitro metabolism of 4-MMC was investigated in Sprague-Dawley rat hepatocytes to characterise the associated Phase I and II metabolites. 4-MMC was incubated with rat liver hepatocytes, and the reaction mixture was analysed...

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Search results for: David G. Watson

Effects of Nigerian red propolis in rats infected with Trypanosoma brucei brucei

A method for the analysis of sugars in biological systems using reductive amination in combination with hydrophilic interaction chromatography and high resolution mass spectrometry

Effect of the sphingosine kinase 1 selective inhibitor, PF-543 on arterial and cardiac remodelling in a hypoxic model of pulmonary arterial hypertension

An evaluation of Minor Groove Binders as anti-lung cancer therapeutics

Evaluation of the technical variations and the suitability of a hydrophilic interaction liquid chromatography-high resolution mass spectrometry (ZIC-pHILIC-Exactive orbitrap) for clinical urinary metabolomics study

Chemical characterisation of Nigerian red propolis and its biological activity against Trypanosoma Brucei

Fenretinide mediated retinoic acid receptor signalling and inhibition of ceramide biosynthesis regulates adipogenesis, lipid accumulation, mitochondrial function and nutrient stress signalling in adipocytes and adipose tissue

Polymeric Nanoparticles of Brazilian Red Propolis Extract: Preparation, Characterization, Antioxidant and Leishmanicidal Activity

Metabolomic Profiling of Post-Mortem Brain Reveals Changes in Amino Acid and Glucose Metabolism in Mental Illness Compared with Controls

Improving arteriovenous fistula patency: Transdermal delivery of diclofenac reduces cannulation-dependent neointimal hyperplasia via AMPK activation

An LCMS method for the assay of melittin in cosmetic formulations containing bee venom

Chromatographic and spectroscopic analysis of the components present in the phenanthridinium trypanocidal agent isometamidium

The Isolation of Antiprotozoal Compounds from Libyan Propolis

Isolation of diterpenes and flavonoids from a new type of propolis from Saudi Arabia

New anti-trypanosomal active prenylated compounds from African propolis

Evaluation of mobile phase characteristics on three zwitterionic columns in hydrophilic interaction liquid chromatography mode for liquid chromatography-high resolution mass spectrometry based untargeted metabolite profiling of Leishmania parasites

A Comparison of Silica C and Silica Gel in HILIC Mode: The Effect of Stationary Phase Surface Area

Development of a method to measure free and bound ropivacaine in human plasma using equilibrium dialysis and Hydrophilic interaction chromatography coupled to high resolution mass spectrometry

The roles of sphingosine kinases 1 and 2 in regulating the Warburg effect in prostate cancer cells

Elucidation of the Phase I and Phase II metabolic pathways of (±)-4′-methylmethcathinone (4-MMC) and (±)-4′-(trifluoromethyl)methcathinone (4-TFMMC) in rat liver hepatocytes using LC–MS and LC–MS2

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