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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The cytotoxicity of the non-steroidal anti-inflammatory drugs in human colorectal cancer cells in vitro : a role for the polyamines?

Hughes, Alun January 2002 (has links)
The non-steroidal anti-inflammatory drugs (NSAIDs) are known to have chemopreventative properties against colorectal cancer. Recent evidence suggests the mechanism of action is not through inhibition of cyclo-oxygenase (COX), as previously thought. We hypothesised that the NSAIDs could be acting through the polyamine biosynthetic pathway. Polyamines play an important role in the development of cancer at all stages from initiation through to maintenance of the transformed phenotype. The aim of this study was to investigate if the polyamines play a role in the cytotoxicity of the NSAIDs in human colorectal cancer cells in vitro. All four drugs (salicylate, sulindac, naproxen and SC'236) displayed cytotoxicity in vitro in three human colorectal cancer cell lines (HT-115, DLD-1 and HCT-15) with comparable IC50 concentrations. All NSAIDs decreased cell growth in the COX-null HCT-5 cells. Sulindac and naproxen caused growth inhibition at low doses but induced apoptosis at higher (>IC50) doses. Salicylate only induced apoptosis in HCT-15 cells and only naproxen and SC'236 induced caspase-3 activity. All NSAIDs depleted intracellular polyamine concentrations to 35-60% of control. Ornithine decarboxylase (ODC) activity was increased in HCT-15 cells but inhibited in DLD-1 cells. Polyamine export was increased in response to NSAID treatment and this was accompanied a 340-530% increase in spermidine/spermine N1-acetyltransferase (SSAT) activity and up to a 500% rise in polyamine oxidase (PAO) activity. Spermidine prevented the growth inhibitory effects of salicylate in HCT-15 cells and inhibited the induction of apoptosis caused by all NSAIDs. Polyamine depletion by pre-treatment with a-difluoromethylornithine (DFMO) decreased the effectiveness of the NSAIDs but did not affect the apoptosis induced. Overall this study highlights several key changes in polyamine metabolism that occurred in response to NSAID treatment. It is our conclusion that polyamines provide an alternative COX-independent pathway for the cytotoxicity of the NSAIDs in vitro, although further work to fully elucidate their role is required.
2

Treatment of PAHs in Wastewater Using Surfactant and PAHs Degradation Bacteria

Chuang, Kung-Shun 29 August 2000 (has links)
In this research¡Awe used three kinds of surfactant ¡Aincluding Triton X-100(nonionic surfactant)¡ATriton QS-15 and SDS(anionic surfactant) ¡Ato study the effects of PAHs degradation bacteria on phenanthrene. In addition¡A we also discussed the treatment effects of salicylate¡A which was functioned as an inducer¡Aon degradation of phenanthrene by the microorganisms with and without the three surfactants. According to the experimental results¡Athe conclusions were as following¡G 1. Biodegradation of PAHs was interfered by species surfactant¡Awhich was affected by the experimental factor¡Aspecies of surfactant and bacteria. 2. In the low level of Triton X-100 system ¡Asalicylate could enhance the degradation of phenanthrene. 3. The effect of degrading phenanthrene was obvious by adding salicylate to the system. 4. In the system containing Aluminum oxide and Triton QS-15¡A it could not enhance the degradation effects on phenanthrene. In the future study¡A we suggest to further discuss the enhancing effects of surfactant on bioremediation of PAHs.
3

Studies on the metabolism of sodium salicylate ... by Eleanor Muriel Kapp ...

Kapp, E. M. January 1942 (has links)
Thesis (Ph. D.)--Columbia University, 1942. / "This article was published under the title 'Urinary metabolites of sodium salicylate' in The Journal of biological chemistry, 145, 549 (1942)." Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 16-17.
4

Studies on the metabolism of sodium salicylate ... by Eleanor Muriel Kapp ...

Kapp, E. M. January 1942 (has links)
Thesis (Ph. D.)--Columbia University, 1942. / "This article was published under the title 'Urinary metabolites of sodium salicylate' in The Journal of biological chemistry, 145, 549 (1942)." Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 16-17.
5

The catabolism of aromatic esters by Acinetobacter sp. ADP1

Jones, Rheinallt M. January 2000 (has links)
No description available.
6

The Search for the Salicylic Acid Receptor LED to Discovery of the SAR Signal Receptor

Kumar, Dhirendra, Klessig, Daniel F. 01 January 2008 (has links)
Systemic acquired resistance (SAR) is a state of heightened defense which is induced throughout a plant by an initial infection; it provides long-lasting, broad-spectrum resistance to subsequent pathogen challenge. Recendy we identified a phloem-mobile signal for SAR which has been elusive for almost 30 years. It is methyl salicylate (MeSA), an inactive derivative of the defense hormone, salicylic acid (SA). This discovery resulted from extensive characterization of SA-binding protein 2 (SABP2), a protein whose high affinity for SA and extremely low abundance suggested that it might be the SA receptor. Instead we discovered that SABP2 is a MeSA esterase whose function is to convert biologically inactive MeSA in the systemic tissue to active SA. The accumulated SA then activates or primes defenses leading to SAR. SABP2's esterase activity is inhibited in the initially/primary infected tissue by SA binding in its active site; this facilitates accumulation of MeSA, which is then translocated through the phloem to systemic tissue for perception and processing by SABP2 to SA. Thus, while SABP2 is not the SA receptor, it can be considered the receptor for the SAR signal. This study of SABPs not only illustrates the unexpected nature of scientific discoveries, but also underscores the need to use biochemical approaches in addition to genetics to address complex biological processes, such as disease resistance.
7

Analgesic efficacy of sodium salicylate in an amphotericin B induced bovine synovitis-arthritis model

Kotschwar, Jamie Lee January 1900 (has links)
Master of Science / Department of Clinical Sciences / Mike D. Apley / Lameness is a common, costly, and painful affliction in cattle at all production levels. There are currently no compounds specifically approved for analgesia in cattle in the United States. We hypothesized that intra-articular amphotericin B produces a controlled, transient synovitis-arthritis in cattle and that this model would allow characterization of the analgesic effects of intravenous sodium salicylate. This study examined the efficacy of sodium salicylate for providing analgesia in an amphotericin B-induced bovine synovitis/arthritis model utilizing ten male Holstein calves, 4-6 months old, and weighing approximately 250 kg. The study used a repeated measures partial cross-over design with 2 phases consisting of 3 treatment periods within each phase. Calves were blocked by weight and randomly assigned to sodium salicylate (50mg/kg intravenously) or placebo group for phase 1. In period 1, lameness induction was simulated with a needle-prick of the coronary band, followed by drug or placebo administration. At predetermined timepoints, serial blood samples for cortisol and salicylate concentrations, electrodermal activity measurements, heart rates, and pressure mat data were collected. Visual lameness scores were recorded by a blinded observer. In period 2, lameness was induced with injection of amphotericin B into the distal interphalangeal joint followed by drug or placebo administration with sample collection as previously described. In period 3, drug or placebo was administered to the respective calves with sample collection. After a 10-day washout, Phase 2 was conducted with treatments crossed over between groups. Cortisol and salicylate samples were analyzed by competitive chemiluminescent immunoassay and fluorescence polarization immunoassay, respectively. The pharmacokinetic data were analyzed using compartmental analysis. Mean intravenous salicylate apparent volume of distribution (V[subscript]d) was 0.2 ± 0.005 L/kg, total body clearance (CL[subscript]B) was 4.3 ± 0.2 mL/min*kg, and elimination half life (T[subscript]1/2 el) was 36.9 ± 1.2 minutes. The repeated measures data were analyzed based on a univariate split-plot approach with a random effects-mixed model. Differences in stance phase duration and serum cortisol concentration values were seen between both periods and treatment group*periods; differences in heart rate, contact surface area, and contact pressure values were seen between periods, suggesting that our lameness model was effective. No differences were seen between treatment groups. When analyzed by visual lameness score, differences were seen in heart rate, contact surface area, contact pressure, and cortisol concentrations. Area under the time-effect curves, determined using the trapezoidal rule, had results similar to the repeated measures data, except for a difference in period for electrodermal activity. This amphoterecin B-induced synovitis/arthritis model is a useful tool for studying changes associated with lameness in cattle. Sodium salicylate was not effective in providing analgesia following lameness.
8

Detecting Organic Molecules on the Surface of Inorganic Dust Particles Using Aerosol Mass Spectrometry

Akinsiku, Sileola B. 01 May 2009 (has links)
Detection of organic molecules present on the surface of dust particles is important in homeland security, agriculture, and several other applications. The research presented reports the ability of the aerosol mass spectrometer (AMS) to detect molecules on the surface of dust particles without detecting the particle core. Experiments were carried out to detect semi-volatile organic compounds adsorbed onto the surface of particulates without interference from the dust particle core. Methyl salicylate, oleic acid, and organophosphorus pesticides such as Malathion were detected on the surface of particles representative of dust-type materials. Zeolite powders were used as aerosol support, representative of a typical silica mineral aerosol present in the atmosphere. Mass spectral fingerprint information was gained by first directly detecting atomized species to record their clean electron impact mass spectrum. This facilitated detection during later experiments of organic molecules coated on an inorganic support. Spectra obtained give mass spectrometric signatures of molecules coated on inorganic particles without detection of the particle core. An important feature of the AMS is the ability to equate an ion rate detected in the mass spectrometer to a mass concentration of a given chemical species in a sample using its ionization efficiency. Based on an average inlet flow rate of 1.2 cm 3sec -1 the ionization efficiencies obtained were 5.89x10-5, 1.15x10-6, and 1.62x10-5 for Malathion, methyl salicylate, and oleic acid, respectively. These experiments and the results obtained show that detection and characterization of organic species adsorbed onto inorganic dust particles are possible at µg m-3 concentrations using the AMS.
9

Effect of Sodium Salicylate, Cisplatin and 5-Fluorouracil in LMP1-Overexpressed Nasopharyngeal Carcinomas Cell Lines

Tsai, Hsien-chu 21 June 2012 (has links)
Nasopharyngeal carcinomas (NPC) is highly induced by Epstein-Barr virus (EBV). EBV infection encoded latent membrane protein 1 (LMP1) is expressed in latent stage II and III of EBV infection nasopharyngeal cells. LMP1 was reported to be associated with increased tumorigenesis, through the activation of nuclear factor-£eB (NF-£eB). In this study, LMP1 overexpressing NPC cell line (TW04) was used for assays of cell proliferation, apoptosis and migration under drug (Sodium Salicylate, Cisplatin and 5-Fluorouracil) treatment. Sodium Salicylate is one of non-steroidal anti-inflammatory (NSAID) drug, which inhibits the downstream of NF-£eB pathway, e.g., COX-1. Cisplatin and 5-Fluorouracil are traditional chemotherapy durgs used in many cancers. Our result shows that overexpression of LMP1 affects cell proliferation, apoptosis , invasion and migration ability. It indicates that LMP1-overexpression is an important marker for NPC therapy.
10

Etude spectroscopique en conditions hydrodynamiques contrôlées du transfert des espèces organiques à l'interface minéral / solution / Spectroscopic study under controlled hydrodynamic conditions of the transfer of organic species at the mineral / solution interface

Rusch, Benoît 12 March 2010 (has links)
Les travaux présentés dans ce mémoire de thèse contribuent à identifier les mécanismes physico-chimiques qui contrôlent le transfert de solutés organiques à l’interface de la phase aqueuse et d’un assemblage minéral de type sable - oxyde de fer comme ceux qui existent dans les sols naturels. Dans le même temps, l’influence des conditions hydrodynamiques sur le transfert a permis de déterminer dans quelle mesure des constantes d’adsorption obtenues en batch sont utilisables pour décrire le transport réactif en milieu poreux. Nous avons synthétisé dans cette étude des matériaux minéraux qui consistent à associer un sable et un oxyde de fer, la gœthite ou l’hématite, respectivement par précipitation (GCS, Goethite Coated Sand) ou par déposition sur le sable (HCS, Hematite Coated Sand). D’après l’étude infrarouge de GCS, les hydroxyles de surface du quartz sont impliqués dans le dépôt d’oxyde de fer tandis que les spectres Raman montrent la contrainte mécanique exercée par les oxydes sur le réseau cristallin du quartz. Ces résultats justifient la forte adhésion de l’oxyde sur le support de quartz. Des expériences d’adsorption du salicylate et du gentisate ont été menées en batch pour comprendre et modéliser les aspects cinétique et thermodynamique de chaque réaction. Pour les expériences en colonne, les paramètres hydrodynamiques (porosité, dispersivité, nombre de Péclet) ont été déduits d’un traçage préalable à l’enregistrement des courbes de percée. Les données macroscopiques provenant de batch et d’une colonne ont été confrontées aux informations moléculaires apportées par des spectres Raman et infrarouge enregistrés après sorption, pour préciser la structure la plus probable du complexe de surface dans chaque cas. Le salicylate sorbé sur GCS forme une structure de type mononucléaire bidentate (chélate), en batch comme en colonne : un oxygène carboxylique et l’oxygène du phénol en ortho sont liés à un atome de fer de la surface de la gœthite. Quel que soit le débit, les courbes de percée du salicylate à travers GCS présentent deux étapes. Ce comportement s’explique par un changement de pH qui modifie la capacité d’adsorption en cours d’expérience, et surtout par un déplacement d’équilibre d’adsorption. Sur GCS, certains sites réactifs de surface sont initialement occupés par des silicates que le salicylate remet en solution pour prendre leur place. Les calculs effectués selon cette hypothèse sont cohérents avec les informations expérimentales. Cette singularité par rapport au gentisate tient aux propriétés de sorption que présente le salicylate vis-à-vis de l’assemblage GCS. Pour les deux molécules, les quantités adsorbées à l’équilibre identiques en batch et en colonne, et la faible évolution des courbes de percée en fonction du débit montrent que l’équilibre thermodynamique local est atteint. Sur le solide HCS, la quantité de gentisate ou salicylate adsorbée en batch est nettement plus grande que celle qui est retenue en colonne. Ce comportement indépendant de la molécule et caractéristique d’un non-équilibre, viendrait avant tout du système HCS (nanohématite sur quartz) en colonne. Les perspectives pour affiner ces explications se situent au niveau des spectroscopies de vibration in situ, capables de suivre l’adsorption en temps réel sans perturber le système : spectres Raman in situ en rétrodiffusion à différentes positions le long de la colonne, spectres infrarouges en réflexion totale atténuée grâce à une fibre optique à l’intérieur de la colonne / The present work contributes to identify the physico-chemical mechanisms controlling the transfer of organic solutes at the interface between an aqueous solution and a mineral assemblage such as sand-iron oxide similar to naturally occurring iron bearing minerals in soils. In parallel, the influence of hydrodynamic conditions on the transfer let to determine under which conditions adsorption constants obtained from batch are suitable to describe reactive transport in porous media. We synthesized in this study some mineral materials based on the association of one sand and one iron oxide, either goethite or hematite, respectively by precipitation (GCS, Goethite Coated Sand) or by deposition on sand (HCS, Hematite Coated Sand). According to the infrared study of GCS, the hydroxyl groups of quartz surface are involved in the iron oxide-coating and Raman spectra show that oxides apply mechanical strain on crystalline lattice of quartz. These findings justify the strong adhesion of the iron oxide on the quartz support. Experiments to study adsorption of salicylate and gentisate were conducted in batch in order to understand and modelize kinetic and thermodynamic aspects of each reaction. For column experiments, the hydrodynamic parameters (porosity, dispersivity, Peclet number) were deduced from a non-reactive tracer experiment before the breakthrough curves of organic compounds were recorded. Macroscopic sorption data from batch and column were confronted to molecular information provided by Raman end infrared spectra recorded after sorption to clarify the most likely structure of surface complex in each case. Salicylate sorbed onto GCS forms a mononuclear bidentate structure (chelate), both in batch and in column: one carboxylic oxygen and the ortho phenolic oxygen bind one iron atom of the goethite surface. Whatever the flow rate is, the breakthrough curves of salicylate through GCS display two stages. This behaviour can be explained by an effect of pH that changes during the adsorption and mostly by the displacement of an adsorption equilibrium. Indeed some reactive surface sites on GCS are initially occupied by silicates and salicylate puts them back to solution when replacing them. Calculations based on this hypothesis agree with experimental data. This singularity of salicylate compared to gentisate is due to sorption properties of salicylate towards GCS assemblage. For both molecules, adsorbed amounts at equilibrium are equal in batch and in column and breakthrough curves do not depend very much on the flow rate, indicating that local thermodynamic equilibrium is achieved in column. On HCS, the amount of gentisate or salicylate sorbed in batch is much higher than that retained in column. This behaviour independent of the molecule is typical of non-equilibrium and may be a characteristic of HCS system (nanohematite on quartz) in column. In prospect, these explanations could be refined by developing in situ vibrational spectroscopies to supervise the adsorption process in real time and without disturbing the system: in situ backscattering Raman spectra at different positions alongside the column and/or attenuated total reflexion infrared spectra by using an optical fiber installed in the column

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