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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.
581

Length of Hospital Stay, Delirium and Discharge Status Outcomes Associated With Anticholinergic Drug Use in Elderly Hospitalized Dementia Patients

Gauthier, Kelly J. 01 January 2006 (has links)
Problem: There are a significant proportion of patients taking acetylcholinesterase inhibitors (ChEi) for cognitive dysfunction also taking medications with anticholinergic (ACh) properties that may counteract their effects. As the number of ACh medications, burden, increases so does the likelihood of an adverse outcome.Background: ACh medications are frequently used in the elderly population (Carnahan 2004) even those with dementia or AD (Roe et al., 2002; Giron et al., 2001; Altavela 2003; Gill et al., 2005; Kogut et al., 2005). Methods: Hospitalized patients > 65 years of age with dementia (AD, other dementias, or with inferred dementia based on ChEi or NMDA antagonist medication use) were studied using UHC clinical database. This document was created in Microsoft Word 2000. Results: Dementia patients on ChEi therapy were more likely to receive an ACh (chi-square 70.1, df=l, pConclusion: A person's age and mental health status along with their current drug regimen, such as ChEi therapy, need to be closely and carefully considered before deciding to use unnecessary ACh drugs in this population which can have detrimental effects.
582

The role of megalin in the transport of aminoglycosides across human placenta

Akour, Amal 05 December 2012 (has links)
Background: Intra-amniotic infections (IAIs) are common complications of labor and delivery. If inadequately treated, these infections can lead to significant morbidity and mortality in the mother and the fetus. Intrapartum aminoglycoside (AG) administration is recommended for the management of IAIs. AGs are known to cross the placenta and achieve bactericidal concentrations in fetal serum. However, the highest and most persistent fetal levels are achieved in renal tissue. So, the fetus may be vulnerable to the nephrotoxic effects of AGs. Megalin, a 600 kDaendocytic receptor, is responsible for the uptake of AGs into renal proximal tubular epithelial cells. This receptor is also expressed in human term placenta and it is reasonable to speculate that it is similarly involved in the placental transport of AGs. However, the mechanisms responsible for placental AG uptake and transport have not yet been characterized. Objective: To evaluate the role of megalin in the transport of AGs across human placenta. Specific aims: (1) To assess and compare megalin expression in term and preterm placental villous tissue, and (2) assess the functional activity of megalin in in vitro placental models. Methods: (1) Following IRB approval, placental tissue samples were collected from pregnant women undergoing term or preterm deliveries. Placental villous tissueswere used to quantify megalin expression by western blotting and q-PCR (2) The human choriocarcinoma cell line (BeWo cells) were grown on Transwell plates, and then megalin expression and function were assessed. Results: Megalin protein and mRNA expression were confirmed in samples of human placental villous tissues. Megalin mRNA expression declined steeply with gestational age till week 31 of gestation then it plateaued thereafter. Also, the expression in the early preterm (n=2) was six fold higher than that of both late preterm (n=3) and term placenta (n=10) (p<0.05). The uptake of 3H-gentamicin by the BeWo cells was time-dependent, saturable (Vmax=42.9 ± 4.9 nmol/mg protein/min; Km=2.93±0.68mM) and partially inhibited by megalin inhibitors. Conclusion: Megalin is expressed in human placental villous tissues as well as the BeWo cells. When grown on Transwell® plates, the BeWo cells appear to be the most appropriate model to study the in vitro transport of AGs across the apical membrane. Time, temperature and concentration dependence of gentamicin uptake in the BeWo cells indicate protein-mediated transport. The inhibition data are consistent with megalin-mediated endocytosis of AGs.
583

Kinetics and mechanisms of accumulation for liposomal ciprofloxacin into rat alveolar macrophages

Mossadeq, Sayeed 01 January 2013 (has links)
The kinetics and mechanism of accumulation for liposomal ciprofloxacin (Lipo-CPFX) into the rat alveolar macrophage NR8383 cells were studied in vitro, in comparison to unformulated ciprofloxacin (CPFX). Upon incubation with CPFX or Lipo-CPFX, cellular drug accumulation was determined from the cell lysates or efflux was from the extracellular media by fluorescence-HPLC. The accumulation for Lipo-CPFX reached the asymptotic values at ≥ 2 hours, which was a result of uptake and efflux. The uptake appeared to be due to liposomes, mediated via cellular energy-independent mechanism like lipid fusion. In contrast, the efflux appeared to be due to ciprofloxacin, partly cellular energy-dependent, and involve probenecid-sensitive multidrug resistance proteins (MRPs). Overall, Lipo-CPFX enabled greater drug accumulation into the NR8383 cells than CPFX. This logically suggests a greater potential to treat respiratory infections especially caused by bacteria resistant to phagocytic killing.
584

DISCOVERY AND BIOPHYSICAL CHARACTERIZATION OF ALLOSTERIC INHIBITORS OF FACTOR XIa (FXIa)

Argade, Malaika 08 August 2012 (has links)
Thrombosis is one of the leading causes of mortality and morbidity that is associated with myocardial infarction, stroke and pulmonary embolism. Anti-thrombotic agents which intend to reduce the occurrence and severity of thrombosis usually target the enzymes of the coagulation cascade. FXIa, a 160 kDa homodimer is gaining popularity of late as a potential target for anti-thrombotic agents due to its relative safety. A number of inhibitors which target the active site of FXIa have been reported but to our knowledge there have been no inhibitors which act via an allosteric mechanism. The aim of this project was to screen for allosteric inhibitors of FXIa from of pool of sulfated small-molecules.These molecules were primarily designed to act as heparin mimetics; heparin being a natural anti-coagulant. These compounds were then analyzed to determine whether inhibition was via an allosteric mechanism.
585

Evaluation of the Pharmacokinetic-Pharmacodynamic relationship, Metabolism and Plasma Protein Binding of the novel antitumor agent, 2-Methoxyestradiol (2ME2), following oral administration in patients with solid tumors.

Lakhani, Nehal Jagdish 01 January 2005 (has links)
The goal of this study was to determine safety, tolerability and pharmacokinetics of 2ME2 in patients with solid tumors and determine maximum tolerated dose (MTD). The following hypotheses were tested: 1) 2ME2 will be well tolerated in clinic when given orally and will have quantifiable effects on the ex vivo markers of angiogenesis and apoptosis; 2) 2ME2 will exhibit linear pharmacokinetics; 3) Plasma protein binding will be extensive and linear; 4) Sulfation will be the major metabolic pathway for 2ME2.This was a phase I dose escalation study. Twenty patients with refractory solid tumors were enrolled. 2ME2 was administered orally starting at 400 mg bid with dose escalation upto 3000 mg bid. Pharmacokinetic sampling was done up to 50 hours after single oral dose for characterization of pharmacokinetics and plasma drug concentrations which were determined by liquid chromatography tandem mass-spectrometry [LC/MS/MS, LOQ: 1ng/mL]. Circulating plasma concentrations were very low at all dose levels with high interindividual pharmacokinetic variability. Median plasma half-life was about 1-2 days. The unphysiologically high oral CL/F and Vd/F reflect low oral bioavailability of 2ME2. There was no dose proportional increase in Cmax or AUClast. There were no dose limiting toxicities at highest dose level, therefore MTD was not defined. The trial was closed due to extremely low plasma concentrations of 2ME2 achieved. Hepatic in vitro metabolism studies showed that 2ME2 was metabolized by CYP 450 enzymes (CYP 1A1, 1A2, 3A4, 3A5 and 2E1) to four major metabolites. Hepatic phase II metabolism studies revealed two major glucuronide metabolites of 2ME2. Sulfation did not play a major role in metabolism of 2ME2. Total in-vivo hepatic clearance was estimated as 862 mL/min, primarily due to glucuronidation. Less than 0.01 % of total administered dose of 2ME2 was excreted unchanged in urine, and about 1% was excreted as glucuronides. Plasma protein binding of 2ME2 was studied using equilibrium dialysis. Mean unbound fraction of 2ME2 (fu) in plasma of patients and healthy human volunteers was 0.019 ± 0.0043 and 0.027 ± 0.0019 respectively. Binding was concentration-independent and unaffected by presence of 2-methoxyestrone. 2ME2 binds to albumin, a1-acid glycoprotein (AAG) and sex-hormone binding globulin (SHBG).
586

SYNTHESIS AND BIOLOGICAL EVALUATION OF SECOND GENERATION ANIBAMINE ANALOGUES AS NOVEL ANTI-PROSTATE CANCER AGENTS

Singh, Shilpa 09 May 2012 (has links)
Prostate cancer is the most prevalent non-cutaneous cancer among men. Since the 19th century when Virchow first introduced the concept of inflammation in cancer, chemokines and their receptors have garnered a lot of interest. Chemokine receptor CCR5 has been especially implicated in many disease states and recently found to be over expressed in prostate cancer cell lines. Anibamine, a natural CCR5 antagonist discovered in 2004, has been found to have significant anti-prostate cancer activity at micromolar level. To optimize this compound and also discover a novel pharmacophore, exploration of the original structure was carried out. Significant modifications were made to the side chain in the original structure and ten different analogues were prepared by altering the original synthetic route. While cytotoxicity assay proved the compounds to be non toxic to normal cells, anti-proliferation assay displayed that having a bulky, hydrophobic group in the side chain of the parent compound is essential for the activity. Looking at this data, the third generation of analogues can be prepared that might generate a better lead compound for the treatment of prostate cancer.
587

A Capillary-Based Microfluidic System for Immunoaffinity Separations in Biological Matrices

Peoples, Michael 01 January 2008 (has links)
The analysis of biological samples in clinical or research settings often requires measurement of analytes from complex and limited matrices. Immunoaffinity separations in miniaturized formats offer selective isolation of target analytes with minimal reagent consumption and reduced analysis times. A prototype capillary-based microfluidic system has been developed for immunoaffinity separations in biological matrices with laser-induced fluorescence detection of labeled antigens or antibodies. The laboratory-constructed device was assembled from two micro syringe pumps, a microchip mixer, a micro-injector, a diode laser with fused-silica capillary flow cell, and a separation capillary column. The columns were prepared from polymer tubing and packed under negative pressure with a stationary phase that consisted of biotinylated antibodies attached to streptavidin-silica beads. A custom software program controlled the syringe pumps to perform step gradient elution and collected the signal as chromatograms. The system performance was evaluated with flow accuracy, mixer proportioning, pH gradient generation, and assessment of detectability. A direct labeling/direct capture immunoaffinity separation of C-reactive protein (CRP) was demonstrated in simulated serum. CRP, a biomarker of inflammation and cardiovascular disease risk assessment, was fluorescently labeled in a one-step reaction and directly injected into the system. A quadratic calibration model was selected and precision and accuracy were reported. Parathyroid hormone was also analyzed by the direct capture approach, but displayed nonspecific binding of human plasma matrix components that limited the useful assay range. Capillary sandwich assays of CRP in human serum and cerebrospinal fluid were performed using both capture and detection antibodies. The detection antibody was labeled and purified offline to minimize signal from labeled matrix components. Four parameter logistic functions were used to model the data and precision and accuracy were evaluated. During the study, 250 nL injection volumes 2.0 µL/min flow rates were employed, minimizing sample and reagent consumption. The microfluidic system was capable of separating antigens from biological matrices and is potentially portable for patient point-of-care settings. Additionally, the flexible design of the separation capillary allows for the analysis of different clinical markers by changing the antibodies and the low assay volume requirements could lead to less invasive patient sampling techniques.LabVIEW version 7 or later is required to open the attached files.
588

To evaluate the level of agreement between two self-reported medication adherence scales and prescription refill records in older adults

Kakad, Priyanka 29 July 2009 (has links)
Objective: To evaluate the level of agreement between two self-reported medication adherence scales and prescription refill records in older adults. Design: Cross-sectional study Setting: Imperial Plaza; a retirement community located in Richmond, Virginia. Participants: 32 independent-living older adults, taking anti-hypertensive medications and filling their prescriptions at on-site Plaza Professional Pharmacy were recruited in the study. Methods: Participants’ 6 months refill records were obtained and Medication Possession Ration (MPR) was calculated. Participants were interviewed using Morisky Medication Adherence Scale (MMAS) & Brief Medication Questionnaire (BMQ). Kappa statistics was used to evaluate the level of agreement. Results: Poor level of agreement was found between refill records and MMAS (k=-0.004), refill records and BMQ belief screen (k=-0.09), regimen screen (k=-0.09), and recall screen (k =-0.004). Strong agreement was found between MMAS and BMQ regimen screen (k=0.79) and recall screen (k=0.87) respectively. Conclusion: Self-reported measure of adherence exhibited poor agreement with prescription refill records.
589

Defining a Simplified Pharmacophore for Simocyclinone D8 Inhibition of DNA Gyrase

Gaskell, Lauren 11 January 2013 (has links)
The type II topoisomerase subfamily of enzymes has been clinically targeted by the widely used, broad-spectrum quinolone class of antibacterials. Due to emerging drug-resistant strains of bacteria, the quinolones’ effectiveness is threatened. The natural product simocyclinone D8 (SD8) has shown the ability to inhibit the type II topoisomerase, DNA gyrase, even when mutated to be resistant to the quinolones. In order to determine the pharmacophore required for SD8 binding to DNA gyrase, 16 compounds were synthesized. These compounds were then tested by surface plasmon resonance for their ability to inhibit the DNA – DNA gyrase binding interaction. It was found that three compounds were able to inhibit the DNA – DNA gyrase binding interaction, while another showed partial inhibition of the interaction. From this data, a minimum pharmacophore was able to be determined. The pharmacophore required a coumarin scaffold bonded to a carboxylic acid group through an approximately 15 Å hydrocarbon linker. Functional supercoiling assays determined that while the compounds were able to bind the enzyme, the binding did not inhibit DNA gyrase’s ability to supercoil DNA.
590

Reversed-phase Ion-Pairing Ultra Performance Liquid Chromatography-Mass Spectrometry in Characterization of Glycosaminoglycans

Alabbas, Alhumaidi 01 January 2014 (has links)
Glycosaminoglycans (GAGs) are a family of linear bio-polysaccharides, which are heterogeneously modified with negatively charged sulfate and carboxylate groups. They are located on every cell surface, extracellular matrix or intracellular space in the body. GAGs are composed of alternating units of an amino sugars (glucosamine or galactosamine) and hexuronic acid/hexose (iduronic acid, glucoronic acid/ or galactose), which are linked by glycosidic bonds with different geometries. In recent years, GAGs have attracted considerable interest. GAGs play vital roles in fundamental biological processes, such as hemostasis, angiogenesis, cell signaling, growth and differentiation. Thus, GAGs contribute to a number of diseases such as thrombosis, cancer, inflammation, osteoarthritis and degenerative diseases. One of the most studied GAGs is heparin, which is widely used as an anticoagulant and is also implicated in other biological processes. Despite its extensive clinical use, heparin continues to suffer from major problems, such as life threatening hemorrhagic complications and heparin-induced thrombocytopenia. These activities originate from the large number of glycan sequences generated during its biosynthesis. Many different enzymes act in a non-template fashion to produce heparin chains with various chain lengths, sulfation and acetylation patterns. Their inherent heterogeneity, complexity and highly anionic nature have seriously limited the development of tools for rapid identification of sequences critical for many biological activities. A RPIP-UPLC MS protocol was developed to separate and characterize structures of heparin oligosaccharides prepared through enzymatic cleavage process and chemoenzymatic synthesis. In designing such protocol, several UPLC and MS parameters were considered. An efficient separation of each oligosaccharide mixture was achieved with different ion-pairing reagents. Yet, the structural elucidation of the multiple chromatographic peaks was hindered by the heterogeneity inherent in these mixtures even with supposedly defined standards. In order to elucidate the structures of these complex molecules, we utilized a strategy, which exploits the ease with which sulfate groups can be fragmented during MS ionization. A systematic increment of the MS cone voltage was employed starting from a minimum dissociation voltage, where the intact molecule is preserved, to a high enough dissociation voltage, where the only core oligosaccharide backbone was retained. This allowed identifying the number of sulfate groups and the core structures. However, positions of substituents were difficult to pinpoint because of the phenomenal number of possibilities. Such analysis would require tandem MS/MS–based approaches.

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