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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.
11

Probing linker design in citric acid-ciprofloxacin conjugates

Milner, S.J., Snelling, Anna M., Kerr, Kevin G., Abd-El-Aziz, A., Thomas, G.H., Hubbard, R.E., Routledge, A., Duhme-Klair, A-K. January 2014 (has links)
No / A series of structurally related citric acid-ciprofloxacin conjugates was synthesised to investigate the influence of the linker between citric acid and ciprofloxacin on antibacterial activities. Minimum inhibitory concentrations (MICs) were determined against a panel of reference strains and clinical isolates of bacteria associated with infection in humans and correlated with the DNA gyrase inhibitory activity. The observed trend was rationalised by computational modelling.
12

Contribution of Glucose Metabolism to the B Lymphocyte Responses

Dufort, Fay Josephine January 2012 (has links)
Thesis advisor: Thomas C. Chiles / B-lymphocytes respond to environmental cues for their survival, growth, and differentiation through receptor-mediated signaling pathways. Naïve Blymphocytes must acquire and metabolize external glucose in order to support the bioenergetics associated with maintaining cell volume, ion gradients, and basal macromolecular synthesis. The up-regulation of glycolytic enzyme expression and activity via engaged B-cell receptor mediated-events was glucose-dependent. This suggests an essential role for glucose energy metabolism in the promotion of B cell growth, survival, and proliferation in response to extracellular stimuli. In addition, the activity of ATP-citrate lyase (ACL) was determined to be crucial for ex vivo splenic B cell differentiation to antibody-producing cells wherein B cells undergo endomembrane synthesis and expansion. This investigation employed knockout murine models as well as chemical inhibitors to determine the signaling components and enzymes responsible for glucose utilization and incorporation into membrane lipids. These results point to a critical role for phosphatidylinositol 3- kinase (PI3K) in orchestrating cellular glucose energy metabolism and glucosedependent de novo lipogenesis for B lymphocyte responses. / Thesis (PhD) — Boston College, 2012. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.
13

Detection of integrins using surface enhanced raman spectroscopy

Gant, Virgil Alexander 29 August 2005 (has links)
Integrins are transmembrane heterodimer protein receptors that mediate adherence to both the intracellular cytoskeleton and extracellular matrix. They play a major role in cellular adhesion and the breadth of their importance in biology is only recently being understood. The ability to detect concentrations of integrins on the cell surface, spatially resolve them, and study the dynamics of their behavior would be a significant advance in this field. Ultimately, the ability to detect dynamic changes of integrins on the surface of a cell maybe possible by developing a combined device such as an atomic force microscope (AFM) and surface enhanced Raman spectroscopy (SERS) system. However, the focus of this research is to first determine if integrins can be detected using SERS. Surface enhanced Raman spectroscopy (SERS) is technique used to detect the presence of analytes at the nanomolar level or below, through detection of inelastically scattered light. This thesis discusses the detection of integrins employing SERS as the detection modality. Integrins have been detected, in solution, using two silver colloids as the enhancing surface. Two silver colloid preparation methods are compared by ease of formulation and degree of enhancement in this thesis. Citrate and hydroxylamine hydrochloride (HA-HCl) reduced silver colloids were prepared through wet chemistry,compared using UV-Vis light spectroscopy, and tested for surface enhancement using adenine (a strong SERS active molecule), and two different integrins, (alpha)V(beta)3 and (alpha)5(beta)1. Results indicated that both colloids demonstrate SERS activity for varying concentrations of adenine as compared to standard non-enhanced Raman, however, only the citrate reduced colloid showed significant enhancement effect for the integrins.
14

Arsenic Adsorption Using Citrate/Fe(III), Silicate/Fe(III) Synthetic Iron Oxides

Chin, Ying-chun 11 September 2006 (has links)
This study is to probe into the surface characteristics, crystalline identification and inner structural changes of the synthetic iron oxides which are synthesized from pure Fe(¢»), citrate/Fe(¢») and silicate/Fe(¢») solutions at different MRs respectively. This study is also to compare the adsorption capabilities of these synthetic iron oxides serving as the adsorptive materials in containing arsenic wastewater through adsorption experiments. By means of the XRD identification analysis, the synthetic iron oxides of pure Fe(¢») and silicate/Fe(¢») are non-crystal ferrihydrite, but the synthetic iron oxide of citrate/Fe(¢») is crystal magnetite with magnetism. By means of IR spectrum analysis and comparison with the IR spectrum of iron mineral, the FTIR spectrum of pure Fe(¢») and silicate/Fe(¢») synthetic iron oxide are similar to that of ferrihydrite; The FTIR spectrum of citrate/Fe(¢») synthetic iron oxide is similar to that of magnetite. The degree of pore volume and surface area for synthetic iron oxides are as follows: silicate/Fe(¢») > Fe(¢») > citrate/Fe(¢»). With the citrate/Fe(¢») MRs increasing, the pore volume and surface area of synthetic iron oxide will decrease. However, with the silicate/Fe(¢») MRs increasing, the pore volume and surface area of synthetic iron oxide do not make great difference. Results of kinetic adsorption experiments show that the synthetic iron oxides of citrate/Fe(¢») or silicate/Fe(¢») at different MRs will adsorb arsenic better at low pH. With the pseudo-first order and the second order kinetic adsorption model to simulate the adsorption experiment data, the results show that the simulation results are consistent with the pseudo-second order kinetic adsorption model. The equilibrium adsorption experiments show that the adsorption capacity of arsenic for synthetic iron oxides is as follows: citrate/Fe(¢») > Fe(¢») > silicate/Fe(¢»), and that the adsorption capacity will decrease with the pH increasing.
15

Detection of integrins using surface enhanced raman spectroscopy

Gant, Virgil Alexander 29 August 2005 (has links)
Integrins are transmembrane heterodimer protein receptors that mediate adherence to both the intracellular cytoskeleton and extracellular matrix. They play a major role in cellular adhesion and the breadth of their importance in biology is only recently being understood. The ability to detect concentrations of integrins on the cell surface, spatially resolve them, and study the dynamics of their behavior would be a significant advance in this field. Ultimately, the ability to detect dynamic changes of integrins on the surface of a cell maybe possible by developing a combined device such as an atomic force microscope (AFM) and surface enhanced Raman spectroscopy (SERS) system. However, the focus of this research is to first determine if integrins can be detected using SERS. Surface enhanced Raman spectroscopy (SERS) is technique used to detect the presence of analytes at the nanomolar level or below, through detection of inelastically scattered light. This thesis discusses the detection of integrins employing SERS as the detection modality. Integrins have been detected, in solution, using two silver colloids as the enhancing surface. Two silver colloid preparation methods are compared by ease of formulation and degree of enhancement in this thesis. Citrate and hydroxylamine hydrochloride (HA-HCl) reduced silver colloids were prepared through wet chemistry,compared using UV-Vis light spectroscopy, and tested for surface enhancement using adenine (a strong SERS active molecule), and two different integrins, (alpha)V(beta)3 and (alpha)5(beta)1. Results indicated that both colloids demonstrate SERS activity for varying concentrations of adenine as compared to standard non-enhanced Raman, however, only the citrate reduced colloid showed significant enhancement effect for the integrins.
16

Étude à double insu sur les effets de l'absorption du citrate de sodium sur la performance d'une course de 400 m plat chez des athlètes de haut niveau

Genest-La Haye, Michel. January 1997 (has links)
Thèses (M.Sc.)--Université de Sherbrooke (Canada), 1997. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.
17

Fine control of citrate synthase from organisms of different physiologies

Flechtner, Valerie Raabe, January 1970 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.
18

Antenatal sildenafil citrate treatment in a mouse model of fetal growth restriction : effects on fetus and offspring

Renshall, Lewis January 2015 (has links)
Fetal growth restriction (FGR), when a fetus fails to reach its genetic growth potential, affects up to 10 % of pregnancies and is a major risk factor for both neonatal and adulthood morbidity and mortality. There are currently no treatments for FGR except for delivery of the fetus; resulting in premature delivery which, in itself, is linked to poor outcome. Therefore, the focus of current research is to examine whether therapies successfully used to treat diseases with similar aetiologies to FGR can also be used to treat FGR. Sildenafil citrate (SC), a selective phosphodiesterase-5 inhibitor, is one such candidate. With the recent announcement of the STRIDER international clinical trial for the treatment of severe FGR with SC, it is imperative to determine the efficacy and safety of SC treatment on both fetus in utero and long-term adult health. Mouse models that mimic characteristics of human FGR represent an attractive model to perform pre-clinical studies. Recent studies in mice have demonstrated that SC increased fetal and placental weight and normalised umbilical artery blood flow velocity in FGR but no studies have assessed effects of antenatal SC on offspring health. The aims of this study were to assess the effect of antenatal SC treatment on a) fetal weight b) fetal vascular reactivity b) pup viability and d) long-term effects on postnatal development/physiology in a mouse model of FGR.All experiments were performed in the placental-specific insulin-like growth factor 2 knockout mouse (Igf2 P0+/- mice) which have mixed litters of wild-type (WT) and growth restricted (P0) mice. It has been reported that SC administered in the drinking water was able to increase P0 fetal weight and thus this mouse model was chosen to assess the effects of SC on the fetus and offspring. SC was administered to pregnant dams in two regimens; orally (120 – 160 mg.kg-1) and subcutaneously (10 mg.kg-1) between E12.5 and E18.5. WT and P0 fetal abdominal aortas were isolated at E18.5 and ex vivo vascular function was assessed using wire myography. Fetal abdominal aortas demonstrated reliable and reproducible vasocontraction and vasorelaxation; there were some sex- and genotype-specific differences. SC demonstrated dose-dependent effects on fetal aortic function. Offspring from dams treated with a subcutaneous injection of SC or saline were assessed for postnatal growth (week 5 – week 12), systolic blood pressure (week 8 and week 13), glucose tolerance (week 12) and mesenteric / aortic vascular function (week 14 – week 16). These experiments demonstrated that;• A supratherapeutic concentration of antenatal SC (120 – 160 mg.kg-1) did not increase fetal weight but significantly blunted relaxation responses of fetal abdominal aortas at E18.5. • A subcutaneous injection of antenatal SC (10 mg.kg-1) did not increase fetal weight or alter fetal abdominal aortic function in mice but led to increased systolic blood pressure in both WT and P0 offspring. Additionally, glucose sensitivity was significantly reduced in female offspring from SC treated dams. In conclusion, the studies outlined in this thesis have demonstrated that antenatal SC treatment can cause alterations in fetal blood vessel function and also lead to changes in metabolic and cardiovascular function in mouse offspring. Using ex vivo wire myography, mouse fetal abdominal aortas were able to be assessed at E18.5. This methodological advance will be beneficial as it can be applied to assessing putative treatments in mice that show characteristics of human FGR. In addition, this technique will allow for investigation of the underlying mechanisms of in utero programming of adulthood cardiovascular diseases such as hypertension. Future work must focus on the mechanisms leading to increased systolic blood pressure in offspring from SC treated dams and whether such effects are noted in other animal models of FGR using a variety of SC dosing regimens. These studies will provide information with which to increase efficacy, and ensure the safety, of SC treatment in pregnancy complications.
19

Intrauterine Insemination Results in Couples Requiring Extended Semen Transport Time

Randall, Gary W., Gantt, Pickens A. 01 January 2007 (has links)
Purpose - The purpose of the present study is to compare intrauterine msemination (IUI) pregnancy rates (PR) as a function of diagnosis and ovulation protocol utilizing an extended semen transport time. This allowed clients to conveniently collect IUI specimens in the comfort and privacy of their home. A single IUI per treatment cycle was performed. Basic Procedures - Three-hundred-ten consecutive infertilty couples having unexplained, male factor, ovulatory dysfunction, endometriosis, tubal factor or combined diagnostic factors receiving a total of 584 cycles of IUI were included. Ovulation protocols included LH surge, clomiphene citrate (CC)-hCG, CC-gonadotropins(Gn)-hCG, Gn-hCG or leuprolide acetate (L)-Gn-hCG followed 36-42 hours by a single IUI. Pregnancy rates per cycle (fecundity) and per couple (fertility) as a function of diagnosis, ovulation protocol and cycle number were evaluated. In each cycle the couples processed the specimen by adding sperm washing medium at room temperature to the specimen 30 min following collection and allowed it to incubate for two hours prior to IUI during transport. Main Findings - Overall, fecundity was 11.8% (69/584) and fertility was 22.3% (69/310); respectively by diagnosis was: unexplained 22.6%,38.8%; male factor 18.8%,42.9%; ovulatory dysfunction 12.4,22.6%; endometriosis 5.3%,11.1%; tubal factor 7.6%,13.3%; and combined factors 9.7%, 20.0%. Unexplained vs endometriosis (P < 0.0001, P < 0.005), tubal factor (fecundity P < 0.008) and ovulatory dysfunction (fecundity P < 0.027) was statistically different. Male factor vs endometriosis (P < 0.011, P < 0.036) was significantly different. Ovulatory dysfunction vs endometriosis was significantly different (fecundity P < 0.027). Pregnancies by ovulation protocol: LH surge 4.5%,10.5%; CC-hCG 9.4%,14.9%; CC-Gn-hCG 13.7%,23.7%; Gn-hCG 17.5%,45.3%; L-Gn-hCG 3.5%,6.7%. For Gn-hCG vs L-Gn-hCG (P < 0.009, P < 0.030) and LH surge (fecundity P < 0.033). CC-Gn-hCG vs CC-hCG (fertility P < 0.050) and L-Gn-hCG (P < 0.033, P < 0.034). Gn-hCG vs CC-hCG (fecundity P < 0.043). Conclusions - We conclude that IUI is effective when utilizing an extended transport time allowing most couples to collect the specimen at home and is most effective when utilizing Gn-hCG therapy. Based on our analysis, endometriosis, tubal factor and combined diagnostic categories should proceed earlier to higher level assisted reproductive technologies.
20

ATP-Citrate Lyase Inhibition Improves Chronic Kidney Disease Through Multiple Mechanisms / ACLY Inhibition In CKD

O'Neil, Kian 11 1900 (has links)
ATP-citrate lyase (ACLY), upregulated in chronic kidney disease (CKD), catalyzes the synthesis of acetyl-coA from citrate. Acetyl-CoA is a vital precursor for lipid/cholesterol synthesis and histone acetylation that regulates gene expression. In renal cells, ACLY regulates fibrogenic, lipogenic and inflammatory gene expression; its inhibition reduced fibrosis in the unilateral ureteral obstruction (UUO) model. The ACLY metabolic by-product malonyl-coA is also an important inhibitor of fatty acid oxidation (FAO), and defective FAO in proximal tubular epithelial cells (PTEC) is now established as a major contributor to fibrosis. Here we tested the efficacy of a novel ACLY inhibitor on reducing fibrosis and its potential role in improving FAO in UUO. 8-week-old male C57BL/6J mice underwent UUO surgery and were treated orally with an ACLY inhibitor (EVT0185, Espervita Therapeutics) for 10 days. Kidneys were assessed by immunohistochemistry, immunoblotting, and RNAseq. Effects of ACLY inhibition were tested on the HK2 PTEC cell line and primary renal fibroblast responses to TGFβ1 (5ng/ml, 48h), a cytokine known to promote fibrosis and reduce FAO. Lipid accumulation was assessed by Oil Red O staining and LC/MS analysis. ACLY inhibition significantly and dose-dependently decreased fibrosis in the UUO model determined by trichrome, PSR, fibronectin, and α-smooth muscle actin (SMA) expression. ACLY inhibition decreased macrophage (F4/80) infiltration including that of the profibrotic M2 phenotype marked by CD206. RNAseq analysis showed upregulation of FAO-related hallmark pathways and reduction in inflammation pathways with ACLY inhibition. Defective FAO is known to result in PTEC apoptosis and lipid accumulation. ACLY inhibition reduced both apoptosis, as assessed by the presence of cleaved caspase 3, as well as lipid accumulation, with a particular decrease in cholesteryl esters. In HK2 cells and renal fibroblasts, TGFβ1-induced fibrotic protein expression was inhibited by ACLY inhibition, and lipid accumulation was reduced in PTECs. ACLY inhibition reduced renal fibrosis, apoptosis, and lipid accumulation in UUO mice. ACLY inhibition also prevented profibrotic responses to TGFβ1 in PTECs and fibroblasts. Current studies are ongoing to confirm beneficial effects on restoring FAO. / Thesis / Master of Science (MSc) / Chronic kidney disease (CKD) is the leading cause of kidney failure in Canada, affecting 4 million Canadians. There is no cure for CKD and current treatments are only able to slow down disease progression. CKD is caused by scarring in the kidney. The kidney requires a lot of energy to do its job filtering our blood and creating urine, and with CKD the ability to create and use energy is reduced. The protein ATP-citrate lyase (ACLY) that is present in the kidney contributes to CKD. Research has shown that people and mice with CKD have higher levels of this protein than healthy individuals. ACLY creates a molecule called acetyl-coA that is likely to cause our kidneys to produce less energy. This study will test if ACLY is causing the kidneys to produce and use less energy. This will be done by using mice with CKD and blocking the activity of ACLY using a drug to see if this will help the kidney create more energy for itself. The kidneys of the mice will be tested to see if the drug worked in increasing energy levels and if it prevented kidney scarring. A type of cell in the kidney, called tubular cells, makes up most of the kidney and requires a lot of energy to function. We performed experiments with tubular cells and gave them stressors, like those found in CKD, and ACLY-blockers to test if the energy levels are restored and if scarring was reduced. This study is important because there is no cure for CKD and many patients will eventually develop end-stage kidney disease, requiring dialysis or transplant. Research needs to be done to create new medications for those suffering from CKD. Current studies are testing ACLY-blocking drugs to treat heart disease. If our study is successful, this drug is well-positioned to be developed into a new treatment for CKD.

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