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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

QUANTITATIVE ANALYSIS OF 5-CHLORO-2-METHOXY-N-[2-(4-SULFAMOYLPHENYL)ETHYL]BENZAMIDE (GLYBURIDE ANALOGUE, GA) IN MOUSE PLASMA AND WHOLE BLOOD USING A MICRO-EXTRACTION AND LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY

Zalavadia, Ankit 01 January 2016 (has links)
Pharmacokinetic evaluation of 5-chloro-2-methoxy-N-[2-(4- sulfamoylphenyl)ethyl]benzamide in mouse plasma demanded for a suitable bioanalytical method. No reported bioanalytical method exists to-date that can quantify concentration of this compound in any biological matrix. The purpose of this study was 1) to develop and validate a new bioanalytical method using a micro-extraction and LC-MS/MS to quantify the target analyte in mouse plasma and 2) to partially validate the method in whole blood. A bioanalytical method was developed and validated in both matrices for a linear concentration range of 2-1000 ng/ml. For both matrices, the reverse predicted concentration of calibration standards (-8.95% to 12.16% and -9.54% to 12.90% respectively) and precision and accuracy (QCs) were within ±15% (%RSD and %BIAS). Four-hour bench top stability and post preparative stability results for plasma and whole blood matrices were within ±15% and ±20% respectively. Blood –plasma concentration correlation co-efficient was 0.9956 with a slope value of 1.018.
2

Identification of Molecules by Spectral Imaging

Alshammari, Qamar 01 May 2019 (has links)
Spectral imaging is a powerful technique which uses the wavelength to identify/quantify the exact location and amount of the molecules. It facilitates the identification of materials and studying their properties through analyzing the way they interact with light. The study of light interaction with elements is called spectroscopy; spectroscopy examines how light behaves in the target and recognizes materials based on their spectral signatures. Spectral signatures can be compared to fingerprints which can be used to identify a person; spectral signatures can be used to identify materials. Therefore, we hypothesize that identifying the exact location and quantity of molecules present in the given cells samples can be done by using a spectral imaging system. In this study, we identify the exact UV-Vis and fluorescence spectra of organic substances including Rhodamine 6G, Doxorubicin and UV-Vis spectra inorganic compounds including silver (Ag), gold (Au) nanoparticles (NPs). After that, we used the Q-TOF LC/MS system to quantify the maximum and minimum detectable concentrations of Rhodamine 6G and Doxorubicin by checking the chemicals spectrum based on the molecular weight. In addition, we used HPLC system to quantify the chemicals basing on their UV spectrum. Forwards, we used spectral imaging system to determine the exact amount and location of the molecules within cells samples. For Rhodamine 6G and doxorubicin, we started with the minimum detectable concentration by Q- TOF and consider it as a maximum limit with spectral imaging. And for NPs we used the maximum concentration for the analysis. Using the spectral imaging we were able to vii detect the exact location of Rhodamine 6G which was in the cytoplasm, Doxorubicin in the nucleoplasm, and NPs in both. Furthermore, spectral imaging was able to detect much lower concentrations of Rhodamine 6G and Doxorubicin by the spectrum in comparison to Q-TOF LC/MS.
3

Kan man påvisa något samband mellan högt sojaintag och bröstcancerrisk?

Blinkowska, Nathalie January 2009 (has links)
No description available.
4

Targeting Primary Cilia Immune Receptor Proteins for the Treatment of Polycystic Kidney Disease Mechanisms

Alomari, Nedaa 19 April 2019 (has links)
Background: Primary cilia are cellular organelles project from the cell surface of mammalian cell and play important roles in vertebrate development, organogenesis, health, and others genetic diseases. Primary cilium functions as a mechano-sensor and chemo-sensor. Defect in primary cilia causes the progression of polycystic kidney disease (PKD) which further leads to the inflammatory responses. We, therefore, investigated the role of Toll-like receptors 4 and 9 (TLR) in primary cilia towards PKD. Purpose: The main purpose of the proposed study is to identify and target the immune reactive proteins i.e. TLRs in the primary cilia. By targeting those primary cilia immune reactive proteins using suitable agonist and antagonists to study the control of cystic formation and their progression mechanisms. Methods: To target the ciliary immune TLR proteins (TLR4 and TLR9), we did immunostaining to evaluate their localization on primary cilia. Cilia lengths were measured and compared using differential interference contrast (DIC) and fluorescent imaging techniques. The in vitro3D cyst progression was monitored by adding agonists lipopolysaccharide (LPS) and oligodeoxynucleotides (ODN) and antagonist 4-hydroxy chloroquine (HCQ). Results: From our results we found that the TLR antagonist HCQ increases ciliary length in treated scrambled control, Pkd2knockout (KO) and TLR4KOcells as an immune response, whereas opposite results were observed with TLR9KO. However, the selected agonists for TLRs (LPS/ODN) increases cilia length in TLR9KO cells and decreases scrambled control, Pkd2KO and TLR4KO. In our 3D cyst cultures, we used agonists and antagonist for both the TLRs and observed that the cyst formations and progressions were inversely related to the cilia lengths. From these observations, we speculated that the new ciliary TLR proteins have a role in cystic progression. In conclusion, we found that the TLRs agonists/antagonist can modulate cilia length and TLRs role in inflammatory actions. The primary cilium already has central roles throughout cell biology, but here we propose, for the first time, that the cilium and the regulation of its structural importance in inflammation of PKD.
5

CLINICAL OUTCOMES ASSOCIATED WITH TIME TO ANTIMICROBIAL THERAPY CHANGE FROM VANCOMYCIN TO DAPTOMYCIN IN STAPHYLOCOCCAL BACTEREMIA

Tennant, Sarah J. 01 January 2016 (has links)
Background: Staphylococcus aureus is an aerobic, Gram positive commensal organism that is capable of causing a wide spectrum of disease. This study contributes to previously published literature regarding daptomycin versus vancomycin use in S. aureus bacteremia (SAB). Methods: Adult patients admitted between 2010 and 2014, billed for ICD-9 code V09.0, 038.11, 038.12, 041.11, or 041.12, and received vancomycin and daptomycin were included in this retrospective analysis. Patients were stratified by time to change in antibiotics from vancomycin to daptomycin to the early switch (1-3 days), intermediate switch (4-7 days), or late switch (8 days or later) group. The primary outcome was treatment failure defined as 30-day recurrence, 60-day all-cause mortality, and 90-day all-cause readmission. Results: 193 patients were enrolled in the final cohort. The overall treatment failure rate was 18% with no differences between early switch, intermediate switch, and late switch (P=0.72) groups. Independent predictors of treatment success were length of stay (OR=1.035) and time to positive culture (OR=0.961). Conclusions: Results of this study did not demonstrate a difference in treatment failure based on time to switch from vancomycin to daptomycin. Future research should focus on optimizing use of vancomycin and daptomycin and medical management of SAB.
6

Evaluation of the Allometric Exponents in Prediction of Human Drug Clearance

Zhang, Da 01 January 2014 (has links)
Background. Allometric scaling (AS) is widely used in predicting human clearance (CL) based on animal data. Substantial prediction errors have been commonly observed and various modifications to AS have not provided a broad reliable improvement. In this study, an extensive data set was assembled including animal and human systemic CL and physiochemical properties. The allometric exponents were calculated based on multiple species AS and single-species AS methods. The correlations between the allometic exponents and physiochemical properties were evaluated in an attempt to find covariates that may explain the inter-compound variability in the allometric exponents. Lastly, the statistical approaches in analyzing the allometric function were evaluated with the collected data. Methods. 1- A nonlinear mixed effect modeling (MEM) approach was performed to investigate the central tendency and distribution of AS exponents as well as to identify whether there are any correlations between the allometric exponent, and coefficient, with the physicochemical and drug metabolism and pharmacokinetics (DMPK) properties of the compounds. 2- Single-species AS was performed to estimate the single-species AS exponent distributions and their corresponding central tendencies. The correlation between the estimated single-species AS exponents and the physicochemical and DMPK properties of the compounds were also examined. 3- The methodologies of log-log transformation followed by linear regression (LL-LR) and direct nonlinear regression methods (NLS) with different weighting schemes on the AS power function were investigated. The central tendency and distribution of the allometric exponents were evaluated and compared across methods. Furthermore, the human CL prediction performance was evaluated among methods. Results. The estimated central tendency and distribution of AS exponents from the nonlinear MEM as well as the single-species AS approaches were consistent with literature reports. There were no significant correlations identified between the estimated AS exponents and the physicochemical or DMPK properties. The methods of LL-LR and the NLS with 1/w2 weighting (variance weighted by CL2 during the variance minimization process) results in the most similar allometric exponent with central tendency around 0.668 and provided the best human CL prediction among methods investigated. Conclusion. The knowledge gained in this work by extensive modeling and simulations contributed to a better understanding of the variability in AS exponents and better practice in performing AS in human CL prediction
7

Enhancement of the Placental Transmission of Lopinavir Using a Transporter Targeted Prodrug Strategy

Wang, Meng 01 January 2015 (has links)
Lopinavir (LPV) is a potent protease inhibitor specific for HIV-1. However, LPV has poor placental penetration due to substrate activity for efflux transporter by P-glycoprotein (P-gp). Since fatty acid transporters are highly expressed in the placenta during pregnancy, we designed fatty acid ester prodrug of lopinavir as substrates of fatty acid transporter in order to improve their uptake into placenta. Seven dicarboxylic acid esters of lopinavir have been made in our lab. The structures were characterized by 1H-NMR, 13C-NMR, LC-MS/MS, HRMS, IR and melting points. After making the prodrugs, an LC-MS/MS method with high specificity and sensitivity, as well as simultaneous quantitative analyses of lopinavir and SLPV, GLPV and DLPV in the BeWo cells methanol extraction was established and validated. The uptake of prodrugs (SLPV, GLPV and DLPV) in the BeWo cells was then determined. GLPV has the highest uptake followed by SLPV and then DLPV. The results suggest that the carbon length of the promoiety may have a positive relationship with the uptake. Ideal prodrugs should be stable before they reach placenta and can be hydrolyzed in the placenta and/or in fetal plasma. We did a series of stability and hydrolysis studies in human tissue fractions. The results showed that GLPV and SLPV were very stable in HIC, HLC and human adult plasma. DLPV was stable in HIC, HLC, but can be hydrolyzed in human adult plasma. GLPV and SLPV cannot be hydrolyzed in either human placenta or fetal plasma, while DLPV can be hydrolyzed in both human placenta and fetal plasma. Anti-HIV activities study of prodrugs was also conducted. The results showed that the EC50 of three prodrugs (GLPV, SLPV and DLPV) are 0.86 μM, 0.84 μM and 0.05 μM, which are much lower than 50 μM (The active drug criteria for this assay). It suggests that prodrugs have apparently anti-HIV activity. DLPV has comparable apparent anti-HIV activity to LPV (<0.02 μM). After incubation with CEM-SS cells for 6 days, almost half of DLPV was hydrolyzed into LPV. Therefore, the high anti-HIV potent of DLPV may be due to the anti-HIV activity of generated LPV.
8

Metabolic Targets of Gnaphalin Mediated Apoptosis in Colon and Pancreatic Cancer Cell Lines

Gardner, Austin, Ngata, Sam, Howard, La'Travia, Cox, Caden, Palau, Victoria 05 April 2018 (has links)
Colorectal and pancreatic cancer are leading causes of cancer related mortality, suggesting the need for further development of treatment approaches. Gnaphalin, a flavone derived from Gnaphalium gracile H. B. K. which is found in the Andean regions of South America, has shown anti-proliferative properties in solid tumors. Further investigation has shown this compound interferes with signaling conducive to proliferation and cell adhesion, inducing the cell to undergo apoptosis. The primary objective of the study was to look at key regulatory proteins in the cell survival and proliferative pathways to determine Gnaphalin’s mechanism of action. Cytotoxic activity was measured using MTT analysis on the colon cancer cell lines Caco2 and HCT-116, and on the pancreatic cancer cell lines MIA PaCa and Panc28. Apoptosis was determined by the presence of fragmented DNA via TUNEL and cleaved effector caspase 3. Finally, immunoblots were used to determine the mechanism of action using key proteins involved in both the intrinsic and extrinsic apoptotic pathways. Gnaphalin showed the highest activities in colon cancer HCT-116 and pancreatic cancer Panc 28 cells with a half maximal effective concentrations of 25.82±1.0887 and 30.07 ± 1.553 µM respectively. Gnaphalin impediment of cell viability involves the inhibition of phospho-ERK proliferation of the MAPK pathway along with phospho-FAK and c-Met, which are adhesion molecules. Gnaphalin has shown cytotoxic activity towards several colon cancer and pancreatic cancer cell lines by targeting cell proliferation and adhesion, and ultimately causing apoptosis.
9

Dopamine Cell Loss within the Nigrostriatal Pathway Due to Oxidative Stress from Chronic Methylphenidate

Ketchem, Shannon, Ensley, Tucker, Oakes, Hannah, Pond, Brooks B. 05 April 2018 (has links)
Attention deficit hyperactivity disorder (ADHD) is a neurobehavioral disorder that affects 11% of children in the US alo­ne. Methylphenidate (MPH) is the most commonly prescribed drug for the treatment of ADHD. Given the fact that ADHD symptoms persist in up to 50% of patients, many children receive MPH from childhood to early adulthood. Unfortunately, most of the scientific literature focuses on the short-term consequences of MPH, even though individuals are taking MPH for many years. MPH acts by blocking dopamine (DA) transporters and norepinephrine transporters, preventing the reuptake of these catecholamines following release. Previous research has shown that long-term exposure to MPH causes dopaminergic neurons within the nigrostriatal pathway to be more sensitive to the Parkinsonian toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We hypothesize that oxidative stress caused by the spontaneous oxidation of the excess DA in the synaptic cleft is what’s rendering dopaminergic neurons within the nigrostriatal pathway to be more sensitive to MPTP. Adolescent male Swiss-Webster mice were divided into three cohorts and administered either saline (control), 1 mg/kg MPH (normal dose) or 10 mg/kg (abusive dose) via intraperitoneal (IP) injections for 12 weeks. Mice were injected twice daily, Monday through Friday, mimicking a school-week dosing schedule. After 12 weeks, all animals received a drug washout period of 7 days. Then, half of each cohort was treated with MPTP (4 x 20mg/kg, every 2 hours), while the other half was administered 4 injections of sterile saline. Seven days after MPTP or saline treatment, the mice were sacrificed, brains were removed, and the substantia nigra (SN) and striatum (STR) were collected. Oxidative stress related to increased DA levels was determined using the glutathione assay to measure glutathione (GSH) content and near-infrared fluorescence dot blots to measure free and protein-bound ortho-quinones. GSH is an important antioxidant and thus its depletion would be indicative of oxidative stress. Additionally, since DA may be oxidized to a quinone, increases in free and protein-bound ortho-quinones also indicate oxidative stress. Interestingly, we observed a significant decrease in GSH as the dose of MPH increased with both saline and MPTP samples. Furthermore, there was a significant increase in quinones as the dose of MPH increased. In conclusion, it appears that long-term exposure to MPH sensitizes dopaminergic neurons within the nigrostriatal pathway to oxidative stress, rendering them vulnerable to further insults, such as MPTP exposure. As such, these studies provide insight into the risks of long-term psychostimulant exposure.
10

THE EFFECT OF NICOTINE CO-ADMINISTRATION ON ALCOHOL-INDUCED REACTIVE HIPPOCAMPAL CELL PROLIFERATION DURING ABSTINENCE IN AN ADOLESCENT MODEL OF AN ALCOHOL USE DISORDER

Heath, Megan 01 January 2016 (has links)
A significant consequence of alcohol use disorders (AUDs) is hippocampal neurodegeneration. The hippocampus is responsible for learning and memory, and neurodegeneration in this brain region has been shown to result in cognitive deficits. Interestingly, some alcoholics demonstrate improvements in hippocampus-dependent functions, potentially due the phenomenon termed adult neurogenesis. Adult neurogenesis, the process by which neural stem cells (NSCs) proliferate, differentiate into neurons, migrate into the granule cell layer, and survive, occurs in two brain regions; however, this study examines only neurogenesis occurring in the subgranular zone of the hippocampal dentate gyrus. Four-day binge ethanol exposure in an animal model causes a decrease in neurogenesis during intoxication; however, there is a reactive increase in cell proliferation on day seven of abstinence. The purpose of this study was to determine the timing of increased cell proliferation. Furthermore, most alcoholics also smoke tobacco, and nicotine, the addictive component of tobacco, has also been shown to affect hippocampal neurogenesis. As many people initiate alcohol and tobacco use during adolescence, the second experiment herein examined the effect of nicotine coadministration on alcohol-induced reactive hippocampal cell proliferation.

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