Recent strategies for anticancer drug design have been focused on utilizing antibody as a drug or targeted moiety for targeted drug delivery. Antibody−drug conjugates (ADCs) have become a promising new class of targeted therapeutic agents for treatment of cancer. ADCs are designed to preferentially direct a cytotoxic drug to a cell-surface antigen recognized by an antibody. However, there are some challenges in developing ADCs, such as limited solid tumor penetration, high manufacturing costs and antibody-drug stoichiometry. Smaller molecules such as peptides have been shown to specifically bind to cancer related targets. These peptides can be used to form peptide-drug conjugates (PDCs) to overcome above-mentioned drawbacks presented by ADCs. In this study, it was hypothesized that novel synthesized PDCs can be a strategy for breast cancer therapy. HER2 specific binding peptides, MARAKE and MARSGL, were modified by addition of a cysteine at C-terminus. The modified peptides were coupled with monomethylauristatin E (MMAE) by using maleimidocaproyl (MC) as a non-cleavable linker to form peptide-drug conjugates (YW1, YW2) and maleimidocaproyl-valine-citrulline (MC-VC) as a cleavable linker to form peptide-drug conjugates (YW3 and YW4). The peptides, peptide-drug conjugates and MC-MMAE, MC-VC-MMAE were characterized using ESI-MS and purified by using high-performance liquid chromatography (HPLC). Cellular uptake study was performed to determine binding specificity and internalization of two HER2 specific peptides and cysteine-modified peptides (MARAKEC, MARSGLC). In vitro cell viability assay was conducted to assess the cytotoxicity and determine the targeting specificity as well as the potency of the peptide-drug conjugates. The purity of each compound was greater than 90%. Internalization of both HER2 specific binding peptides and cysteine-modified peptides were significantly higher than random peptides in HER2 over-expressed cell lines, MDA-MB361 and ZR75, while negligible uptake in HER2 negative cell line, HEK293. MC linked PDCs showed similar cytotoxicity as peptide in all cell lines; while MC-VC linked PDCs have higher cytotoxicity than MMAE in HER2 positive cell line and significant lower cytotoxicity than MMAE in normal cell line HEK293. However, PDCs with MC link do not show significant difference in cytotoxicity compared to the peptide in all cell lines. In conclusion, specificity of HER2 binding for both peptides was preserved after modification with cysteine. The derivation of MMAE to link drug and peptide played a crucial role in the anticancer activity. Peptide-MMAE conjugates with cleavable linker showed a promising targeting capability for delivery of MMAE to HER2 overexpressed cancer cells.

Transthyretin (TTR) amyloidosis is a progressive, fatal disease in which deposition of amyloid derived from either mutant or wild-type TTR causes severe organ damage and dysfunction. TTR cardiomyopathy is an infiltrative, restrictive cardiomyopathy characterized by progressive left and right heart failure. Familial amyloid cardiomyopathy (FAC) is driven by pathogenic point mutations in the TTR gene that destabilize the TTR tetramer, prompting its dissociation into dimers and monomers, with subsequent misfolding, aggregation and deposition of toxic TTR amyloid aggregates in the myocardium. The most prevalent mutation that causes FAC is the V122I variant, carried by 3.4% of African Americans, that increases the risk of cardiomyopathic events several-fold in this population. AG10, a potent TTR kinetic stabilizer, prevents dissociation of V122I-TTR in serum samples obtained from patients with FAC. Further, we have described structural, biochemical, and animal studies of AG10 which reveal mechanistic and structural insights on the ability of AG10 to mimic the disease suppressing T119M variant in stabilizing TTR. The second part of the thesis discusses harnessing TTR as a platform to enhance in vivo half-life (t1/2) of therapeutic peptides. Native peptides typically display short in vivo t1/2, however conjugation of peptides to macromolecules causes steric hindrance which often harms the binding of peptides to target receptors, compromising the in vivo efficacy. Utilizing Gonadotropin Releasing Hormone (GnRH) as a model peptide, we show that t1/2 may be extended without compromising potency. Our approach involves endowing peptides with a small molecule that binds reversibly to the serum protein transthyretin. Our strategy was effective in enhancing the t1/2 of an agonist for GnRH receptor while maintaining its binding affinity, which was translated into superior in vivo efficacy. The third and final part of the thesis describes our effort on developing a fluorescent probe to quantify TTR in human serum using fluorescence polarization. TTR is used as a marker for nutritional and inflammatory status in critical patients. This assay development has the potential to minimize lab cost, effort, and time with regards to determination of TTR concentration in patients.

Natural products are of great significance to the pharmaceutical industry in the development of new drugs. Diquinane or bicyclo[3.3.0]octane is a conspicuous structural unit existing in the carbo-frameworks of a wide range of natural products such as alkaloids and terpenoids. These diquinane-containing molecules not only exhibit intriguing architectures, but also showcase a broad spectrum of significant bioactivities, which draw widespread attention from the global synthetic community. A more specific group of compounds containing a diquinane moiety with one extra 5-membered ring are called the angular triquinanes.In this work, we have developed a general synthetic scheme to the angular triquinanes. We envisioned relatively quick access to the angular triquinane ring system, with each ring bearing synthetically useful functionalization, by direct palladium catalyzed [3+2] cycloaddition of a trimethylenemethane (TMM) unit with functionalized bicyclo[3.3.0]octeneones. This was performed with two different realized bicyclo[3.3.0]octenone substrates. The bicyclo[3.3.0]octeneones can be obtained by [3+2] addition of a TMM-based diradical with an olefin. This synthetic approach allows for the access of trisubstituted angular triquinanes with substitution on each of the three rings in the system, conveniently designed for further derivatization into more complex structures. One of the resulting angular triquinanes from our designed synthesis, containing all-cis fused stereochemistry, was further elaborated to display its utility as an easily manipulated angular triquinane containing a ketone equivalent on each of the three rings in the system. Some diquinane intermediates and final triquinane products were subjected to a biological assay to examine potential cytotoxicity against MDA-MB-468 cancer cells. Additionally, we have designed molecules containing both cyclopentane and polyquinane (diquinane and triquinane) ring systems as DNA polymerase α inhibitors based initially on the structure of the known DNA polymerase α inhibitor, aphidicolin. Optimal design was determined and predicted by docking of the designed ligands to the binding pocket in the active site in the crystal structure of DNA polymerase α (4Q5V) through several iterations with the use of Autodock Vina software. Some of the top designed inhibitors with respect to their binding affinity were synthesized in the laboratory and subjected to a human DNA polymerase α assay.

The opioid crisis remains a severe public health challenge, exacerbated by the high incidence of overdose deaths associated with powerful synthetic opioids like fentanyl. Naloxone, an opioid antagonist, is a critical component in emergency responses to these overdoses due to its ability to rapidly reverse opioid effects. However, naloxone’s short duration of action limits its efficacy, particularly in environments with delayed medical follow-up. This dissertation presents a novel naloxone delivery system utilizing advanced prodrug technology to extend its therapeutic effects. The proposed system, based on a compound, AG10-Linker that enhances naloxone’s pharmacokinetic profile by modulating the solubility and absorption of a naloxone prodrug, thereby facilitating controlled and extended release of naloxone. This research investigates the synthesis, physicochemical properties, and in vivo efficacy of a naloxone prodrug formed by conjugating naloxone with AG10-Linker, demonstrating its potential to provide sustained protection against opioid toxicity. The findings suggest that this innovative approach could significantly impact clinical practice and the broader field of addiction medicine by improving outcomes in managing opioid overdoses.

<p> The aim of this thesis is to evaluate the impact of somatostatin receptor subtype-4 (SSTR4) actions on microglia cell viability, towards the understanding and advance of pharmacological treatments for Alzheimer&rsquo;s disease (AD). As of March 2016, there were 5 million people living in the United States with AD. Current drugs for AD have highly variable effects from patient to patient and are palliative at best. This thesis project focuses on the study of the BV2 cell line and the compound NNC 26-9100 (NNC). BV2 cells are immortalized microglial cells that maintain most of their morphology. The data collected suggests that BV2 cells can phagocytize amyloid-? peptides (A?), respond to lipopolysaccharide (LPS), and have the somatostatin receptor subtype-4 (SSTR4). NNC is a selective agonist of the SSTR4 and we have found that it causes BV2 cells to increase in number. The effects of NNC were able to be reduced with a somatostatin receptor pan-antagonist, cyclosomatostatin, and the adenyl cyclase activator forskolin. NNC can alter BV2 numbers by binding to the SSTR4, creating an intracellular cascade that results in the inhibition of adenyl cyclase and an increase in cell count. Collectively, a potential therapeutic mechanism for AD is increasing the number of microglial cells to increase both amyloid beta (A?) phagocytosis and degradation of A? by neprilysin.</p>

<p> The role of the professional nurse has evolved in numerous and unexpected ways since the founding of Nightingale&rsquo;s first school of nursing in 1860. One contemporary sphere in which nurses work is the biopharmaceutical and medical device industry, but little research exists regarding how the nurse engages with and experiences this role. </p><p> This qualitative, phenomenological study was undertaken to address the research question: What is the nature and process of the transition experience from a direct patient care role to a clinical research specialist role for the professional nurse? Two subquestions were also explored: What barriers and supports are encountered during the transition process? What facilitates successful work role transition from direct patient care to clinical research? </p><p> Ten professional nurses who had transitioned to industry based careers at least two years prior to this study were identified and selected via referral sources. Each nurse participated in a series of three in-depth recorded interviews. Through an iterative process of transcript review, coding, and thematic analysis, and utilization of Ashforth&rsquo;s (2001) ABCs of Role Identification and Nicholson&rsquo;s (1984, 2013) Work Role Transition Theory as lenses for interpretation, seven key themes emerged. These themes include: 1) I am alone: transition can be an isolating experience, 2) I am unprepared: transition requires mastery of unfamiliar skills and knowledge, 3) I am scared and sometimes overwhelmed: transition is associated with a lack of security, structure and balance, 4) I can do it: self-reliance and resourcefulness facilitate successful work-role transition, 5) I need to build new bridges: transition requires networking and support from others, 6) I am becoming: the transition experience can be empowering and offers opportunity for growth, and 7) I am still a nurse: nursing identity and values endure through transition. </p><p> This study offers several recommendations for further research to more deeply explore identified themes and ways to facilitate success in this work-role transition. In addition, using feedback from study participants, recommendations and suggestions are offered for nurse educators, professional nursing credentialing organizations, and to other nurses considering a career in the clinical research arena.</p>

The small, high sediment yield Waipaoa River is located on the tectonically active, mountainous Poverty Margin on the east coast of the North Island, New Zealand. In contrast to sedimentary sequences on passive margin shelves, active margins, such as the Poverty Margin, can preserve continuous records of changing geological and environmental conditions at the land-sea interface during rapid sea-level rise. Two subsiding mid-shelf basins on the Poverty Shelf contain thick transgressive sequences which provide a record of evolving river, climate, landscape, and oceanographic conditions since the Last Glacial Maximum (LGM). This dissertation investigates the stratigraphic development of Poverty Shelf, including event layer preservation, over the last ∼14ka using geochemical proxies and physical properties analyses of the sedimentary record. The work herein was conducted under the auspices of the MARGINS Source-to-Sink program, a multi-national, interdisciplinary study focused on understanding sediment routing, transformation and fate through the Waipaoa Sedimentary System (WSS) from catchment sources to final sinks on the adjacent Poverty Shelf and Slope. A suit of five giant piston cores and eight box cores were retrieved from Poverty Shelf during two cruises to address long (Holocene) and short (modern) timescales, respectively, of deposition. Geochronological, geochemical and sedimentological profiles from the giant piston cores are used to reconstruct the processes that influenced shelf infilling during this critical period of recent earth history. Accumulation rate analyses from high-resolution radiocarbon profiles and tephrachronology, along with X-radiographic facies analysis, enable tracking of rapidly shifting loci of deposition from the slope to mid-shelf depocenters. Grain size profiles and delta13C values reveal sympathetic changes that track the waxing and waning influences of sediment supply via the Waipaoa River as sea level rose to maximum flooding at ∼7ka, subsequent Poverty Bay shoreline reorganization and changing shelf accommodation, and, in the last ∼1ka, a strong anthropogenic signal. Imprinted upon this record is evidence for temporal and spatial changes in event layer frequency and type throughout the Holocene. Event layers may be produced by extreme and episodic storms, floods, earthquakes and other perturbative events that punctuate background marine sedimentation with large additions of terrestrial sediment. Event layers can be identified by unique textural and geochemical characteristics. An event layer, likely emplaced via hyperpycnal flow, attributed to Cyclone Bola (1988), the most severe modem cyclone on record in this location, serves as a modem benchmark for other storm events in the Poverty Shelf records. Examination of X-radiographs and lithostratigraphy, textural and isotopic variability reveal that the Poverty Shelf stratigraphic record preserves evidence of exceptional event sedimentation in the past and present that can be distinguished from shifts in supply, transport, and accumulation of sediments due to longer-time scale perturbations related to climate, sea level, and tectonics. A period of increased fidelity of the event record in the mid-Holocene is observed associated with increased accommodation within rapidly flooded depocenters.

No description available.

L'inhibition des cytochromes P450 (CYPs) humains est l'un des mécanismes les plus fréquents à l'origine d'interactions médicamenteuses. L'inhibition des CYPs peut être réversible ouirréversible. L'inhibition irréversible provient souvent de l'activation d'un médicament, par action des CYPs, en métabolite réactif qui se lie stablement au site actif de l'enzyme, provoquant une inactivation permanente. Ce processus est appelé « inhibition suicide ».L'inhibition irréversible implique souvent la formation d'une liaison covalente entre le métabolite et l'enzyme, qui crée une protéine haptenisée qui peut, dans certains cas, provoquer une réponse auto-immunitaire.Il est donc important d'étudier les mécanismes d'inhibition des CYPs par de nouvelles molécules à visées thérapeutiques le plus tôt possible dans leur processus de développement.Dans cette thèse on propose une stratégie pour éviter le développement de médicaments quipourraient provoquer l'inhibition suicide des CYPs dans les patients.1) Après compilation de la littérature, on a créé une base de données de toutes les molécules responsables d'inhibition suicide des CYPs. Cette base met en évidence les structures les plussouvent responsables de l'inactivation et permet de donner une alerte pour une structure nouvelle.2) On a mis au point et validé une nouvelle méthode fluorimétrique, pour déterminer quantitativement l'inhibition dépendant du temps du CYP3A4, utilisable à moyen débit. Grâce à cet outil, on a établi des relations structure-activité pour un groupe de composés furaniquesdifféremment substitués.3) Deux composés de cette série, qui montraient une inhibition suicide nette du CYP3A4 ont été étudiés plus complètement à l'aide de molécules radiomarquées au 14C. Ces molécules sontactivées en intermédiaires réactifs capables de se fixer de façon covalente aux protéines. Leur métabolisme a été partiellement analysé.

<p> Although chronic allograft damage (CAD) remains a primary barrier to long-term renal allograft survival, limited progress has been made in the discovery of potential therapeutics. In order to identify potential drug therapies, we used two meta-analytical methods to evaluate six post-renal transplant blood and biopsy gene expression data sets (N=275). This resulted in a list of 85 differentially expressed genes that were examined using the Connectivity Map Database (cMAP) in order to identify drugs with the capacity to interrupt the differential gene expression associated with CAD. Among the top ranking drugs, we identified kaempferol and esculetin as promising candidates, and we tested their therapeutic efficacy in a mouse unilateral ureteral obstruction (UUO) model and explored their putative mechanisms of action in renal tubular cells in vitro. Kaempferol and esculetin significantly decreased TGF&beta; and wnt mediated pro-fibrotic signaling and abrogated renal fibrosis in the UUO model, and in renal tubular cells in vitro. Therefore, kaempferol and esculetin represent potential novel anti-fibrotic agents in the treatment of CAD.</p>