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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

Utilization of HBPE Nanoparticles for Optimizing Drug Delivery to Cancer Cells

Nierenberg, Daniel 01 January 2021 (has links) (PDF)
Nanoparticles (NPs) use for drug delivery or vaccines is highly successful. Given this, optimizing a NP's biological identity for maximal therapeutic benefit remains challenging. Macromolecules absorption from biofluids by NPs forms a layer called the protein corona. Herein, we examined a corona's influence on the uptake of polymeric NPs, made with a hyperbranched polyester polymer (HBPE), by breast cancer cells. Moreover, a corona's ability to increase cancer killing through improved paclitaxel (taxol) drug delivery was evaluated. Normal and influenza A virus (IAV)-infected mice sera were employed as coronal protein sources. Pre-coating NPs with sera may enrich NP surfaces with proteins that favor cancer interaction. In turn, a NP's ability to reach tumors may be enhanced by exploiting normal or IAV sera content. For normal and IAV sera studies, polyethylene glycol (PEG), a gold-standard NP surface modification for in vivo delivery, served as a control to sera-incubated HBPE-NPs. Sera pre-coated HBPE-NPs exhibited enhanced breast cancer cell uptake and tumor localization, over PEGylated HBPE-NPs. Additionally, breast cancer treatment with sera pre-coated HBPE-NPs resulted in greater taxol-mediated killing compared to PEGylated HBPE-NP treatment. Sera pre-coated HBPE-NPs additionally demonstrated greater uptake in cancer cells in an in vitro transwell system. The transwell system involved NP treatment in an upper chamber containing endothelial cells and assaying NP uptake in a lower chamber containing cancer cells. IAV sera coating enhanced NP localization to breast cancer tumors, while lowering liver and spleen accumulation in mice. We show HBPE-NPs incubation with normal and immune response-derived IAV sera can form coronas with unique proteins. Our findings suggest that sera collected during an immune response to infection are a rich source of coronal proteins that could form the basis of a preformed protein corona that ensures the optimal biological identify for targeted cancer cell uptake as described herein.
2

Determining the Advantageous Acute Migraine Treatment: Rimegepant and Lasmiditan Review of Literature

Johnson, Tiffany A 01 January 2020 (has links)
This research aims to evaluate two new pharmaceuticals on the market. Rimegepant and Lasmiditan target the trigeminovascular system and respectively, are characterized in the gepant and ditan classes of pharmaceuticals. Based on a review of studies, Rimegepant was determined to be the advantageous acute treatment. This is not conclusive due to inequivalent comparison in sample size and amount of research completed. It is encouraged for additional research to be imposed before a conclusive determination of the advantageous acute treatment can be distinguished.
3

The effects of an adenosine A(2A) agonist as an adjunctive treatment to alleviate sensorimotor gating deficits in a rodent model of schizophrenia

Rauhuff, Hannah 01 May 2020 (has links)
The adenosine system has become a promising target for the treatment of schizophrenia due to its unique relationship with dopamine D2 receptors. Dopamine D2 receptors display heightened sensitivity in schizophrenia, and inhibition of these receptors has been shown to alleviate some of the psychotic symptoms of the disorder. Inhibition of adenosine A(2A) receptors has been shown to decrease dopamine D2 receptor sensitivity, making this receptor a potential target for treatment of the disorder. This effect occurs because adenosine A(2A) receptors form a mutually inhibitory heterodimeric complex with dopamine D2 receptors. The present study looked at the effects of an adenosine agonist on prepulse inhibition (PPI) and cyclic-AMP response binding element protein (CREB) concentrations in the nucleus accumbens (NAc) using a rodent model of schizophrenia (NQ model) that presents with increased D2 receptor sensitivity. Results showed that the A(2A) agonist was effective in improving PPI in NQ-treated animals. The agonist was also effective in reducing increased CREB concentrations in the NAc of NQ-treated animals to control levels. The effectiveness of the agonist suggests that the adenosine system may be a viable target for the treatment of some of the psychotic symptoms associated with schizophrenia.
4

A HYBRID MOLECULE OF MELATONIN AND CURCUMIN FOR THERPEUTIC USE IN PULMONARY FIBROSIS

Nair, Varsha V 01 January 2019 (has links)
Pulmonary fibrosis (PF) is a serious lung disease, as its life expectancy is only 3-5 years upon occurrence and more than 50 % of the cases are idiopathic, i.e., unknown cause. Two drugs, pirfenidone (PIR) and nintedanib, have recently been approved; however, their efficacies are moderate without evidence of prolonged survival. While this is primarily due to our insufficient knowledge about key PF pathogenesis, inductions of oxidative stress and transforming growth factor-b1 (TGF-b1) have been suggested in PF lungs. Hence, anti-oxidative melatonin (MEL) and curcumin (CUR) have been studied yet their efficacies remain moderate without clear understanding about the mechanisms of action. Accordingly, this project hypothesized that a novel hybrid molecule of MEL and CUR, AM24, was a more potent inhibitor against oxidative stress and TGF-b1 induced PF pathobiologic events than MEL or CUR, so that its pulmonary delivery enabled therapeutic intervention in an animal model of PF. Free radical scavenging activity and various in vitro lung cell-based anti-fibrotic activities of AM24 were determined and compared with those of MEL and CUR as well as their admixture (MEL+CUR) and PIR. Pulmonary administration of AM24 was then examined for therapeutic intervention in a rat model of bleomycin (BLM)-induced experimental PF. AM24 was equipotent to MEL, but less potent than CUR in the hydrogen peroxide-induced free radical (ABTS) scavenging assay, ranked with the half-maximal inhibitory concentration (IC50) of 25.7, 32.0 and 11.4 uM, respectively. However, in the in vitro human lung fibroblast systems, AM24 was shown to be more potent than MEL or CUR and notably than MEL+CUR or PIR in the TGF-b1 induced 1) collagen synthesis by the picrosirius red assay, 2) proliferation by the MTT assay; and 3) differentiation to myofibroblast by western blot analysis of a myofibroblast marker, a-smooth muscle actin (a-SMA). In detail, at 10 uM, AM24 inhibited TGF-b1 induced 1) collagen synthesis by 90 %; 2) proliferation by ~72 %; and 3) differentiation to myofibroblast completely, while MEL, CUR, MEL+CUR and PIR resulted in 30-55 % or insignificant inhibition. In addition, in the in vitro human lung alveolar epithelial cell system, AM24 at 10 uM almost completely inhibited TGF-b1 induced epithelial-mesenchymal transition (EMT), as measured with western blot expressions of an epithelial marker, E-cadherin, and a mesenchymal marker, vimentin. Again, MEL, CUR, MEL+CUR and PIR exerted much less inhibitory activities. Hence, all these results consistently suggested that AM24 was a unique hybrid molecule of MEL and CUR and possessed highly potent anti-fibrotic activities in addition to the free radical scavenging activity. AM24 was then examined for therapeutic intervention in an in vivo rat model of BLM-induced PF. BLM was orotracheally spray-dosed to the lungs at 0.6 mg/kg on day 1 to develop experimental PF in 14 days. Lung administrations of AM24 at 0.1 mg/kg commenced at 6 hours of BLM induction on day 1 and continued thrice weekly over two weeks. Functional treadmill exercise endurance was measured on day 12 and 15; and lungs were harvested upon sacrifice on day 16. Overall, AM24 showed significant intervention activities as follows: 1) exercise endurance was reduced only ~20%, much lower than 78% of the untreated PF rats; 2) reduced fibrotic tissue area and alveolar structural destruction were seen by histological examinations; and 3) lung’s induced collagen deposition was inhibited by ~78 %. However, unlike the literature, the lung’s TGF-b1, PCNA (a cell proliferation marker), and a-SMA (a differentiation marker), were not largely induced in the BLM-induced PF model, so that the intervention activities of AM24 to these markers were not clearly shown. In contrast, induced EMT was seen in the BLM-induced model, represented by increased mesenchymal marker, vimentin, and by decreased epithelial marker, E-cadherin; and AM24 appeared to counter this induced EMT. Accordingly, while the BLM-induced PF model may need further optimizations for clearer pathogenic changes, AM24 exerted certain degree of in vivo efficacies with a lung dose of 0.1 mg/kg, which was much lower than the effective doses of MEL, CUR, PIR and nintedanib seen in the literature with BLM induced PF model. In conclusion, this thesis study has provided an early proof-of-concept for AM24, a novel MEL-CUR hybrid molecule, being potently anti-oxidative and anti-fibrotic in the in vitro lung cell-based assessments. As a result, AM24 enabled therapeutic intervention just with a lung dose of 0.1 mg/kg in the BLM-induced rat model of experimental PF.
5

Synthesis of Bis(imino)pyridine Iron(II) Complexes and Development of Bis(imino)pyridine Iron(II) Catalyzed Carbene Transfer Reactions

Wang, Ban 01 October 2019 (has links)
Metal catalysis of symmetric and asymmetric carbene transfer reactions has been widely applied in natural product synthesis and material science over years. Metal carbene can be easily generated from the extrusion of nitrogen under the catalysis of metal complexes to further undergo various organic reactions, O/N/C-H insertions, cycloadditions, and ylide formations. Currently, the dominant effective catalysts for carbene reactions are built with expensive precious metal, for example, rhodium, ruthenium, palladium, gold. Notably, the effective reactivity and enantioselectivity of the dirhodium(II) catalysts are researched and established over the decades. However, the use of precious metal catalysts is the major source of metal residues in pharmaceutical products; thus, it becomes a concerning safety factor towards the environment. Iron, instead, to our interest, is an economical and ecofriendly element. Iron has been used in different catalytic reactions but achieved moderate reactivity and low enantioselectivity towards carbene transfer reactions. Within, the electronic environment and the mechanism of iron catalysts are underdeveloped. A new series of ligands named bis(imino)pyridine family has been found to be able to offer coordinate sites for transition metals to build effective metal complexes can be used for different organic reactions. This type of ligand can be easily synthesized in relatively short steps and the structure of the substituents can be facially tuned. These advantages show the great potential of bis(imino)pyridine ligands in organic catalysis. In this project, bis(imino)pyridine ligands were applied as the backbone structure to construct a series of achiral and chiral iron catalysts that were investigated in catalytic metal carbene reactions in terms of reactivity and selectivity. By manipulating the structure of the ligands, the high reactivity of the achiral iron(II) complexes towards various carbene reactions was achieved, while moderate enantioselectivity was observed by the catalysis of chiral iron(II) complexes. To our delight, the bis(imino)pyridine iron(II) complex, for the first time, is shown as an effective metal carbene catalyst for carbene transfer reactions of donor–acceptor diazo compounds. Its broad catalytic capability is demonstrated by a range of metal carbene reactions, from cyclopropanation, cyclopropenation, epoxidation, and Doyle–Kirmse reaction to O–H insertion, N–H insertion, and C–H insertion reactions. The asymmetric cyclopropanation of styrene and methyl phenyldiazoacetate was successfully achieved by the new chiral bis(imino)pyridine iron catalyst, which delivers a new gateway for the development of chiral iron catalysis for metal carbene reactions.
6

Clinical Trial and Error: An Assessment of the Food and Drug Administration's Implementation of Breakthrough Therapy Designation

Lin, Molly 01 January 2016 (has links)
This thesis explores the effectiveness of the Food and Drug Administration’s implementation of Breakthrough Therapy Designation (BTD), focusing on the low number of approval rates and repercussions of BTD for the development of new drugs for patients suffering serious life threatening illnesses. BTD, as an expedited review process, shows potential for improvement in its guidelines for necessary qualifications for BTD. Cutting costs, through a shortening in development time, and raising profits, through first mover status of new to market drugs, BTD is regarded by pharmaceutical executives as a tool to insure not only return on investment but also the rewards that accompanies a profitable blockbuster drug. Lessons learned from activism from 1980’s HIV/AIDS crisis show how advocates and “activist-experts” can rebalance and refocus more attention on the necessary beneficence for patients. A policy stipulation that insures all members: corporate, regulatory, and patient advocate, sit together at the decision making table will insure a more balanced discussion in regards to drug development.
7

Formulation Optimization for Pore Lifetime Enhancement and Sustained Drug Delivery Across Microneedle Treated Skin

Ghosh, Priyanka 01 January 2013 (has links)
Microneedle (MN) enhanced drug delivery is a safe, effective and efficient enhancement method for delivery of drug molecules across the skin. The “poke (press) and patch” approach employs solid stainless steel MN to permeablize the skin prior to application of a regular drug patch over the treated area. It has been previously shown that MN can be used to deliver naltrexone (NTX) at a rate that provides plasma concentrations in the lower end of the therapeutic range in humans. The drug delivery potential of this technique is, however, limited by the re-sealing of the micropores in a 48-72h timeframe. The goal of the current research was to optimize the formulation for a 7 day MN enhanced delivery system for NTX either by adding a second active pharmacological moiety or by optimizing formulation characteristics alone. Three different formulation strategies were explored: formulation pH optimization with NTX; a codrug approach with NTX and a nonspecific cyclooxygenase inhibitor, diclofenac (DIC); and a topical/transdermal approach with NTX and an enzyme inhibitor of the cholesterol synthesis pathway, fluvastatin (FLU). The results indicated that formulation pH cannot be used to extend micropore lifetime, although formulation optimization leads to enhanced transport and thus drug delivery across MN treated skin. The codrug approach was successful in extending the micropore lifetime and further screening of codrug structures and formulation optimization helped in selection of a codrug candidate suitable for evaluation in animal pharmacokinetic studies. Local treatment with FLU helped to keep the micropores open and enabled delivery of NTX for an extended period. The pores re-sealed on removal of treatment within a 30-45 minute timeframe, indicating that infection/irritation should not be a major issue, as in the case of other topical chemical enhancers. Thus, overall it can be concluded that different formulation strategies can be utilized to extend micropore lifetime and enhance delivery of drug molecules across the skin.
8

THE SLC22 TRANSPORTER FAMILY: NOVEL INSIGHTS TO ROLES IN DRUG EFFICACY, DRUG-DRUG INTERACTIONS AND MOOD DISORDERS

Pan, Xiaolei 01 January 2015 (has links)
Numerous studies have demonstrated the impact of organic cation (OCTs; SLC22 family) and anion transporters (OATs; SLC22 family) on the efficacy and safety of clinically important therapeutics. To be specific, OCTs and OATs have been identified as determinants for uptake into and secretion from enterocytes, hepatocytes and renal proximal tubular cells, and are frequent sites of drug-drug interaction (DDI). In addition, OCTs expressed in brain are components of the low-affinity, high capacity clearance pathway (uptake-2) for biogenic monoamine neurotransmitters. As a result, OCTs may represent novel targets for mood disorders. The inhibitory effects of several therapeutic agents, designed drugs and novel compounds were assessed on the function of OCTs/Octs and OATs/Oats. Among these compounds, the anthraquinone rhein showed significant inhibition on hOATs. While the antituberculosis drug ethambutol, the herbal products matrine and oxymatrine, synthetic cathinones, and all quinazoline and guanidine compounds produced significant inhibition on hOCT activity with most IC50 values in the micro- and even nanomolar ranges. Considering the clinically relevant unbound concentrations in biofluids, significant DDI potentials were found for rhein, ethambutol, matrine, oxymatrine and several synthetic cathinones affecting enterocytes, hepatocytes and/or proximal tubules. As hOCT2 and hOCT3 may participate in modulating neurotransmitter homeostasis in the CNS, these findings also suggested that the CNS pharmacological effects of synthetic cathinones, quinazoline and guanidine compounds might be due to their inhibitory effects on OCTs; although their impact may be limited solely to clearance of these compounds. Based upon their in vitro OCT/Oct inhibition profiles, three lead quinazoline and guanidine compounds were chosen for in vivo studies. Potent antidepressant-like effects of one lead hOCT-interacting compound (KEO-099) were re-confirmed in the tail suspension test. While in vivo results of the two newly identified hOCT-interacting lead compounds were somewhat less clear. Finally, homology modeling and docking studies for hOCT3 identified key amino acid residues that might be involved in interaction between hOCT3 and small molecules. Subsequent experiments confirmed a competitive mode of interaction between MPP+ and lead compounds on hOCT3. Thus, preliminary analysis indicates our hOCT3 homology model can be used to support rational drug design and high-throughput screening of novel hOCT substrates/inhibitors.
9

DEVELOPMENT OF COCAINE HYDROLASE FOR THERAPEUTIC TREATMENT OF COCAINE ABUSE

Chen, Xiabin 01 January 2016 (has links)
Cocaine abuse is a world-wide public health and social problem without a U.S. Food and Drug Administration (FDA)-approved medication. An ideal anti-cocaine medication would accelerate cocaine metabolism producing biologically inactive metabolites by administration of an efficient cocaine-specific exogenous enzyme. Recent studies in our lab have led to discovery of the desirable, highly efficient human cocaine hydrolases (hCocHs) that can efficiently detoxify and inactivate cocaine without affecting normal functions of central nervous system (CNS). Preclinical and clinical data have demonstrated that these hCocHs are safe for use in humans and effective for accelerating cocaine metabolism. However, the actual therapeutic use of a hCocH in cocaine addiction treatment is limited by the short biological half-life (e.g. 8 hours or shorter in rats) of the hCocH. In the investigation described in this thesis, we have demonstrated that mCocH and hCocH have improved the catalytic efficiency of mBChE and hBChE against cocaine by ~8- and ~2000-fold, respectively, although the catalytic efficiencies of mCocH and hCocH against other substrates, including acetylcholine (ACh) and butyrylthiocholine (BTC), are close to those of the corresponding wild-type enzymes mBChE and hBChE. In addition, we have identified the first benzoylecgonine-metabolizing enzymes that can hydrolyze benzoylecgonine and accelerate its clearance in rats. The developed LC-MS/MS method has enabled us to simultaneously determine cocaine and nine cocaine-related metabolites in whole blood samples. In development of the long-acting hCocHs, we have designed and discovered a novel hCocH form, catalytic antibody analog, which is an Fc-fused hCocH dimer (hCocH-Fc). The hCocH-Fc has not only a high catalytic efficiency against cocaine, but also a considerably longer biological half-life. A single dose of hCocH-Fc was able to accelerate cocaine metabolism in rats even after 20 days and, thus, block cocaine-induced hyperactivity for a long period of time. In consideration of the general observation that the biological half-life of a protein drug in humans is significantly longer than that in rodents, the hCocH-Fc could allow dosing once every 2-4 weeks, or longer for cocaine addiction treatment in humans.
10

Towards Elucidation of a Viral DNA Packaging Motor

Schwartz, Chad T. 01 January 2013 (has links)
Previously, gp16, the ATPase protein of phi29 DNA packaging motor, was an enigma due to its tendency to form multiple oligomeric states. Recently we employed new methodologies to decipher both its stoichiometry and also the mechanism in which the protein functions to hydrolyze ATP and provide the driving force for DNA packaging. The oligomeric states were determined by biochemical and biophysical approaches. Contrary to many reported intriguing models of viral DNA packaging, it was found that phi29 DNA packaging motor permits the translocation of DNA unidirectionally and driven cooperatively by three rings of defined shape. The mechanism for the generation of force and the role of adenosine and phosphate in motor motion were demonstrated. It was concluded that phi29 genomic DNA is pushed to traverse the motor channel section by section with the aid of ATPase gp16, similar to the hexameric AAA+ family in the translocation of dsDNA. A new model of "Push through a One-way Valve" for the mechanism of viral DNA packaging motor was coined to describe the coordinated interaction among the hexameric packaging ATPase gp16 and the revolution mechanism of the dodecameric channel which serves as a control device to regulate the directional movement of dsDNA.

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