Medical Sciences Commons^™

The Influence, Dependency, And Targeting Of Fatty Acid Uptake In Er+ Breast Cancer, Abigail E. Goen

Dartmouth College Ph.D Dissertations

Estrogen Receptor-positive/ Human Epidermal Growth Factor 2-negative, breast cancer (ER+/HER2- BC) is the most prevalent subtype of BC, impacting millions of individuals. Although early screening and treatment with endocrine therapy has greatly enhanced survival, this subtype sustains a steady increase of risk for recurrent disease for decades after diagnosis, indicating the persistence of residual cancer cells that are capable of maintaining dormancy for >20 years prior to metastatic outgrowth. Dormant cells reprogram metabolic pathways which can be profoundly influenced by the tumor microenvironment in promoting quiescence or proliferation. Fatty acid oxidation dependency has been noted as a hallmark of drug …

The Structure, Dynamics, And Impact Of An Interbacterial Weapon Encoded By Human Gut Bacteria, Casey John Latario

Dartmouth College Ph.D Dissertations

The human gut is densely colonized by diverse bacteria. Over a human’s growth, the GI tract becomes a dynamic community that is subjected to a continual in-flow of nutrients and would-be colonizers and an out-flow of microbes and waste products. Despite these dynamics, the bacterial community often displays stability, with particular strains persisting over decades. These stable colonizers have evolved mechanisms to bolster their colonization, resist disruption by other microbes, and persist through environmental flux.

Both interbacterial competition and horizontal gene transfer (HGT) contribute to colonization and survival within the GI tract. A major mechanism for interbacterial competition is the …

Evaluating Updated Fentanyl Immunoassays For Loperamide Interference, Michael E. Walsh, Grace R. Williams, Paul J. Jannetto, K. Aaron Geno

Dartmouth Scholarship

Background

Loperamide is a µ-opioid receptor agonist that reduces intestinal peristalsis and is used to treat diarrhea. We previously described significant cross-reactivity of loperamide with 2 fentanyl immunoassays. Since then, new fentanyl immunoassays, including a CLIA-waived point-of-care device, have been approved for clinical use. Methods

We evaluated new fentanyl immunoassays for cross-reactivity to loperamide and its major metabolites, N-desmethyl loperamide (dLop) and N-didesmethyl loperamide (ddLop). Previously characterized assays were tested for cross-reactivity to ddLop, which recently became commercially available. Loperamide, dLop, and ddLop were spiked in drug-free urine for analysis by 5 enzyme immunoassays run on automated chemistry analyzers and …

Advancing Novel Contrast Agents For Applications In Fluorescence-Guided Neurosurgery Using Fluorescence Cryotomography, Augustino Vittorio Scorzo

Dartmouth College Ph.D Dissertations

Fluorescence guided surgery (FGS) is an emerging surgical technique that aims to help surgeons identify tissue types to assist in surgical decision making - ideally providing “cut-by-color” guidance. A primary application for this approach is the identification of tumor tissue to achieve more accurate and complete tumor removal while simultaneously minimizing damage to surrounding normal tissue. The cornerstone of tumor visualization for FGS is the administration of fluorescent contrast agents, or in some cases metabolic precursors, designed to accumulate specifically in tumor tissue, and a wide range of agents that use different targeting mechanisms are currently under investigation. Although these …

Novel Combination Therapies For Estrogen Receptor-Positive Breast Cancer Driven By Rational Molecular Mechanisms, Anneka Lila Johnson

Dartmouth College Ph.D Dissertations

Breast cancer (BC) is the most common non-keratinocyte cancer diagnosed in women in the United States with approximately 300,000 new cases diagnosed each year. Despite a myriad of treatment options, BC remains the second-most deadly cancer. Estrogen receptor-positive (ER+) BC comprises 60-70% of BC diagnoses and is treated with endocrine therapies that limit ER signaling. Despite endocrine therapy options, ~1/3 of patients experience recurrence within 10-20 years of diagnosis. Novel therapeutic strategies are required to limit BC recurrence-related morbidity and mortality.

Radiotherapy is used as an adjuvant treatment for ER+ BC patients prior to the use of endocrine therapy. Radiation …

Deep Learning For Fine-Grained Digital Histopathology Image Analysis, Joseph Dipalma

Computer Science Technical Reports

As digital pathology becomes increasingly popular, it is critical to develop machine learning solutions to utilize this data. While other image modalities have seen exponential increases in methodology availability, the same has not been true for histopathology images. This is likely in part because histopathology whole slide images possess unique characteristics that prevent simply applying existing methods as-is.

In this thesis, we identify and propose solutions to 3 open problems with histopathology images: 1. large raw image size (up to 150,000×150,000 pixels in size), 2. low class-positivity (low ratio of positive to negative patches), and 3. limited image availability with …

Targeting The Cholesterol Storage Enzyme Acat1/Soat1 In Brain Cells And Mouse Model: A Novel Approach To Address Aging And Apoe4-Related Neuroinflammation, Thao Nguyen Phuong Huynh Krumeich

Dartmouth College Ph.D Dissertations

Alzheimer’s Disease (AD) is a progressive neurodegenerative disease that significantly impacts nearly 7 million people in the United States. AD is characterized by the deposition of amyloid beta (Ab) plaque, tau neurofibrillary tangles (NFTs), lipids granules, and neuroinflammation. Age and apolipoprotein E4 (APOE4) are the two biggest risk factors for AD. Recent AD therapeutic development has mostly benefited the patient population with milder symptoms while causing serious side effects in APOE4 carriers, leaving the most impacted patients’ group - aged APOE4 carriers with no treatment option. With the increasing aging population, there is an urgent need for a …

Combination Therapy Of Ido1 Inhibition And Anti-Pd1 Mediates Anti-Tumor Immunity By Promoting Memory Immunity Development And Cytotoxicity Of Γδ T And Nk Cells Via Il-2 Signaling And By Overcoming Pro-Tumor Effects Of Tgf-Β Signaling, Hyuk Jee

Dartmouth College Master’s Theses

Cutaneous melanoma is the most aggressive form of skin cancer even though it takes only about 1% of all skin cancers. Even among all cutaneous melanomas, NRAS-mutant melanoma is more aggressive than any other, and about 10-25% of all cutaneous melanoma cases have mutations in NRAS. NRAS is a member of the RAS family of proto-oncogenic GTPase proteins, and it plays a key role in signal transduction pathways responsible for cellular survival, proliferation, and metabolism. Immunotherapy is the first line of defense against NRAS-mutant melanoma because, despite tremendous efforts made for decades, it has not been successful to develop small …

Deep Learning Approaches For Cancer Prognosis Prediction Using Histopathological, Omics, And Clinical Data, Shuai Jiang

Dartmouth College Ph.D Dissertations

Accurate prediction of patient outcomes is crucial for shared clinical decision-making, treatment planning, and patients' psychological adjustment. Histopathological features of cancer, including tumor size, lymph node involvement, and metastasis, are commonly incorporated into survival prediction models, underscoring the prognostic value of whole slide images (WSIs). Concurrently, studies have highlighted the significance of omics data, such as transcriptomics, in providing valuable insights into cancer prognosis.

The emerging deep learning methods have brought new opportunities in biomedical informatics. Despite a growing body of studies on the application of deep learning methods for predicting prognosis using WSIs, the results are varied, primarily due …

Advancing Clinical Bacterial Diagnosis: Gram-Stained Whole-Slide Image Classification With Attention-Based Deep Learning, Jack Mcmahon

Computer Science Senior Theses

We introduce a new method for the classification of Gram-stained WSIs. As a test for the diagnosis of blood infections, Gram stains are highly relevant to informing patient treatment. Rapid analysis of Gram stains has been shown to be positively associated with better clinical outcomes, indicating the need for better tools to aid in automatic Gram stain analysis. To date, this area of research has been underexplored, with previous studies relying on the manual patch-level annotation of WSIs to generate training data. This is the first application of a transformer-based model to Gram-stain WSI classification, an approach that is far …

Accelerated Forgetting In People With Epilepsy: Pathologic Memory Loss, Its Neural Basis, And Potential Therapies, Sarah Ashley Steimel Phd

Dartmouth College Ph.D Dissertations

While forgetting is vital to human functioning, delineating between normative and disordered forgetting can become incredibly complex. This thesis characterizes a pathologic form of forgetting in epilepsy, identifies a neural basis, and investigates the potential of stimulation as a therapeutic tool. Chapter 2 presents a behavioral characterization of the time course of Accelerated Long-Term Forgetting (ALF) in people with epilepsy (PWE). This chapter shows evidence of ALF on a shorter time scale than previous studies, with a differential impact on recall and recognition. Chapter 3 builds upon the work in Chapter 2 by extending ALF time points and investigating the …

Automatic Recognition, Segmentation, And Sex Assignment Of Nocturnal Asthmatic Coughs And Cough Epochs In Smartphone Audio Recordings: Observational Field Study, Filipe Barata, Peter Tinschert, Frank Rassouli, Claudia Steurer-Stey, Elgar Fleisch, Milo Puhan, Martin Brutsche, David Kotz, Tobias Kowatsch

Dartmouth Scholarship

Background: Asthma is one of the most prevalent chronic respiratory diseases. Despite increased investment in treatment, little progress has been made in the early recognition and treatment of asthma exacerbations over the last decade. Nocturnal cough monitoring may provide an opportunity to identify patients at risk for imminent exacerbations. Recently developed approaches enable smartphone-based cough monitoring. These approaches, however, have not undergone longitudinal overnight testing nor have they been specifically evaluated in the context of asthma. Also, the problem of distinguishing partner coughs from patient coughs when two or more people are sleeping in the same room using contact-free audio …

Introduction To Covid-19 Research, Amanda Scull

Dartmouth Library Workshops and Presentations

No abstract provided.

Characterization Of A Non-Contact Imaging Scintillator-Based Dosimetry System For Total Skin Electron Therapy., Irwin I. Tendler, Petr Bruza, Michael Jermyn, Xu Cao, Benjamin B. Williams, Lesley A. Jarvis, Brian W. Pogue, David J. Gladstone

Dartmouth Scholarship

Surface dosimetry is required for ensuring effective administration of total skin electron therapy (TSET); however, its use is often reduced due to the time consuming and complex nature of acquisition. A new surface dose imaging technique was characterized in this study and found to provide accurate, rapid and remote measurement of surface doses without the need for post-exposure processing. Disc-shaped plastic scintillators (1 mm thick  ×  15 mm [Formula: see text]) were chosen as optimal-sized samples and designed to attach to a flat-faced phantom for irradiation using electron beams. Scintillator dosimeter response to radiation damage, dose rate, and temperature were …

Signal Intensity Analysis And Optimization For In Vivo Imaging Of Cherenkov And Excited Luminescence., Ethan P. M. Larochelle, Jennifer R. Shell, Jason R. Gunn, Scott C. Davis, Brian W. Pogue

Dartmouth Scholarship

During external beam radiotherapy (EBRT), in vivo Cherenkov optical emissions can be used as a dosimetry tool or to excite luminescence, termed Cherenkov-excited luminescence (CEL) with microsecond-level time-gated cameras. The goal of this work was to develop a complete theoretical foundation for the detectable signal strength, in order to provide guidance on optimization of the limits of detection and how to optimize near real time imaging. The key parameters affecting photon production, propagation and detection were considered and experimental validation with both tissue phantoms and a murine model are shown. Both the theoretical analysis and experimental data indicate that the …

Calibration And Analysis Of A Multimodal Micro-Ct And Structured Light Imaging System For The Evaluation Of Excised Breast Tissue., David M. Mcclatchy Iii, Elizabeth J. Rizzo, Jeff Meganck, Josh Kempner, Jared Vicory, Wendy A. Wells, Keith D. Paulsen, Brian W. Pogue

Dartmouth Scholarship

A multimodal micro-computed tomography (CT) and multi-spectral structured light imaging (SLI) system is introduced and systematically analyzed to test its feasibility to aid in margin delineation during breast conserving surgery (BCS). Phantom analysis of the micro-CT yielded a signal-to-noise ratio of 34, a contrast of 1.64, and a minimum detectable resolution of 240 ?m for a 1.2?min scan. The SLI system, spanning wavelengths 490?nm to 800?nm and spatial frequencies up to 1.37 , was evaluated with aqueous tissue simulating phantoms having variations in particle size distribution, scatter density, and blood volume fraction. The reduced scattering coefficient, and phase function …

Neural Responses To Naturalistic Clips Of Behaving Animals Under Two Different Task Contexts, Samuel A. Nastase, Yaroslav O. Halchenko, Andrew C. Connolly, M. Ida Gobbini, James V. Haxby

Dartmouth Scholarship

The human brain rapidly deploys semantic information during perception to facilitate our interaction with the world. These semantic representations are encoded in the activity of distributed populations of neurons (Haxby et al., 2001; McClelland and Rogers, 2003; Kriegeskorte et al., 2008b) and command widespread cortical real estate (Binder et al., 2009; Huth et al., 2012). The neural representation of a stimulus can be described as a location (i.e., response vector) in a high-dimensional neural representational space (Kriegeskorte and Kievit, 2013; Haxby et al., 2014). This resonates with behavioral and theoretical work describing mental representations of objects and actions as being …

Closed-Loop Stimulation Of Temporal Cortex Rescues Functional Networks And Improves Memory, Yousseff Ezzyat, Paul A. Wanda, Deborah F. Levy, Allison Kadel, Ada Aka, Isaac Pedisich, Michael R. Sperling, Ashwini D. Sharan, Bradley C. Lega, Alexis Burks, Robert E. Gross, Cory S. Inman, Barbara C. Jobst, Mark A. Gorenstein

Dartmouth Scholarship

Memory failures are frustrating and often the result of ineffective encoding. One approach to improving memory outcomes is through direct modulation of brain activity with electrical stimulation. Previous efforts, however, have reported inconsistent effects when using open-loop stimulation and often target the hippocampus and medial temporal lobes. Here we use a closed-loop system to monitor and decode neural activity from direct brain recordings in humans. We apply targeted stimulation to lateral temporal cortex and report that this stimulation rescues periods of poor memory encoding. This system also improves later recall, revealing that the lateral temporal cortex is a reliable target …

Small Rna Teg49 Is Derived From A Sara Transcript And Regulates Virulence Genes Independent Of Sara In Staphylococcus Aureus, Adhar Manna, Samin Kim, Liviu Cengher, Anna Corvaglia, Stefano Leo, Patrice Francois, Ambrose L. Cheung

Dartmouth Scholarship

Expression of virulence factors in Staphylococcus aureus is regulated by a wide range of transcriptional regulators, including proteins and small RNAs (sRNAs), at the level of transcription and/or translation. The sarA locus consists of three overlapping transcripts generated from three distinct promoters, all containing the sarA open reading frame (ORF). The 5= untranslated regions (UTRs) of these transcripts contain three separate regions 711, 409, and 146 nucleotides (nt) upstream of the sarA translation start, the functions of which remain unknown. Re- cent transcriptome-sequencing (RNA-Seq) analysis and subsequent characterization indicated that two sRNAs, teg49 and teg48, are processed and likely produced …

Intrinsic And Innate Defenses Of Neurons: Détente With The Herpesviruses, Lynn Enquist, David A. Leib

Dartmouth Scholarship

Neuroinvasive herpesviruses have evolved to efficiently infect and establish latency in neurons. The nervous system has limited capability to regenerate, so immune responses therein are carefully regulated to be nondestructive, with dependence on atypical intrinsic and innate defenses. In this article we review studies of some of these noncanonical defense pathways and how herpesvirus gene products counter them, highlighting the contributions that primary neuronal in vitro models have made to our understanding of this field.

Anxiety Associated Increased Cpg Methylation In The Promoter Of Asb1: A Translational Approach Evidenced By Epidemiological And Clinical Studies And A Murine Model, Rebecca T. Emeny, Jens Baumert, Anthony S. Zannas, Sonja Kunze, Simone Wahl, Stella Iurato

Dartmouth Scholarship

Epigenetic regulation in anxiety is suggested, but evidence from large studies is needed. We conducted an epigenome-wide association study (EWAS) on anxiety in a population-based cohort and validated our finding in a clinical cohort as well as a murine model. In the KORA cohort, participants (n= 1522, age 32–72 years) were administered the Generalized Anxiety Disorder (GAD-7) instrument, whole blood DNA methylation was measured (Illumina 450K BeadChip), and circulating levels of hs-CRP and IL-18 were assessed in the association between anxiety and methylation. DNA methylation was measured using the same instrument in a study of patients with anxiety disorders recruited …

Aspergillus Fumigatus Trehalose-Regulatory Subunit Homolog Moonlights To Mediate Cell Wall Homeostasis Through Modulation Of Chitin Synthase Activity, Arsa Thammahong, Alayna K. Caffrey-Card, Sourabh Dhingra, Joshua J. Obar, Robert Cramer

Dartmouth Scholarship

Trehalose biosynthesis is found in fungi but not humans. Proteins involved in trehalose biosynthesis are essential for fungal pathogen virulence in humans and plants through multiple mechanisms. Loss of canonical trehalose biosynthesis genes in the human pathogen Aspergillus fumigatus significantly alters cell wall structure and integrity, though the mechanistic link between these virulence-associated pathways remains enigmatic. Here we characterize genes, called tslAand tslB, which encode proteins that contain domains similar to those corresponding to trehalose-6-phosphate phosphatase but lack critical catalytic residues for phosphatase activity. Loss of tslA reduces trehalose content in both conidia and mycelia, impairs cell wall …

Filamentous Fungal Carbon Catabolite Repression Supports Metabolic Plasticity And Stress Responses Essential For Disease Progression, Sarah R. Beattie, Kenneth Mark, Arsa Thammahong, Laure Nicolas Annick Ries, Sourabh Dhingra, Alayna Caffrey-Carr, Chao Cheng

Dartmouth Scholarship

Aspergillus fumigatus is responsible for a disproportionate number of invasive mycosis cases relative to other common filamentous fungi. While many fungal factors critical for infection establishment are known, genes essential for disease persistence and progression are ill defined. We propose that fungal factors that promote navigation of the rapidly changing nutrient and structural landscape characteristic of disease progression represent untapped clinically relevant therapeutic targets. To this end, we find that A. fumigatus requires a carbon catabolite repression (CCR) mediated genetic network to support in vivo fungal fitness and disease progression. While CCR as mediated by the transcriptional repressor CreA is …

Production Of Putative Enhanced Oral Cholera Vaccine Strains That Express Toxin-Coregulated Pilus, Caitlyn A. Hauke, Ronald K. Taylor

Dartmouth Scholarship

The use of whole cell killed (WCK) oral cholera vaccines is an important strategy for cholera prevention in endemic areas. To overcome current vaccine limitations, we engineered strains of V. cholerae to be non-toxigenic and to express the protective protein colonization factor, toxin-coregulated pilus (TCP), under scale-up conditions potentially amenable to vaccine production. Two V. cholerae clinical strains were selected and their cholera toxin genes deleted. The tcp operon was placed under control of a rhamnose-inducible promoter. Production and stability of TCP were assessed under various conditions. The strains lack detectable cholera toxin production. The addition of 0.1% …

Cis-Eqtl-Based Trans-Ethnic Meta-Analysis Reveals Novel Genes Associated With Breast Cancer Risk, Joshua Hoffman, Rebecca Graff, Nima Emami, Caroline Tai, Michael Passarelli

Dartmouth Scholarship

Breast cancer is the most common solid organ malignancy and the most frequent cause of cancer death among women worldwide. Previous research has yielded insights into its genetic etiology, but there remains a gap in the understanding of genetic factors that contribute to risk, and particularly in the biological mechanisms by which genetic variation modulates risk. The National Cancer Institute's "Up for a Challenge" (U4C) competition provided an opportunity to further elucidate the genetic basis of the disease. Our group leveraged the seven datasets made available by the U4C organizers and data from the publicly available UK Biobank cohort to …

A Novel Multi-Network Approach Reveals Tissue-Specific Cellular Modulators Of Fibrosis In Systemic Sclerosis, Jaclyn N. Taroni, Casey S. Greene, Viktor Martyanov, Tammara A. Wood

Dartmouth Scholarship

Systemic sclerosis (SSc) is a multi-organ autoimmune disease characterized by skin fibrosis. Internal organ involvement is heterogeneous. It is unknown whether disease mechanisms are common across all involved affected tissues or if each manifestation has a distinct underlying pathology.We used consensus clustering to compare gene expression profiles of biopsies from four SSc-affected tissues (skin, lung, esophagus, and peripheral blood) from patients with SSc, and the related conditions pulmonary fibrosis (PF) and pulmonary arterial hypertension, and derived a consensus disease-associate signature across all tissues. We used this signature to query tissue-specific functional genomic networks. We performed novel network analyses to contrast …

A New Class Of Inhibitors Of The Arac Family Virulence Regulator Vibrio Cholerae Toxt, Anne K. Woodbrey, Evans O. Onyango, Maria Pellegrini, Gabriela Kovacikova, Ronald Taylor, Gordon Gribble, F. Jon Kull

Dartmouth Scholarship

Vibrio cholerae is responsible for the diarrheal disease cholera that infects millions of people worldwide. While vaccines protecting against cholera exist, and oral rehydration therapy is an effective treatment method, the disease will remain a global health threat until long-term solutions such as improved sanitation and access to clean water become widely available. Because of this, there is a pressing need for potent therapeutics that can either mitigate cholera symptoms, or act prophylactically to prevent the virulent effects of a cholera infection. Here we report the design, synthesis, and characterization of a set of compounds that bind and inhibit ToxT, …

Hyper-Methylated Loci Persisting From Sessile Serrated Polyps To Serrated Cancers, Angeline S. Andrew, John A. Baron, Lynn F. Butterfly, Arief A. Suriawinata, Gregory J. Tsongalis, Christina M. Robinson, Christopher I. Amos

Dartmouth Scholarship

Although serrated polyps were historically considered to pose little risk, it is now understood that progression down the serrated pathway could account for as many as 15%–35% of colorectal cancers. The sessile serrated adenoma/polyp (SSA/P) is the most prevalent pre-invasive serrated lesion. Our objective was to identify the CpG loci that are persistently hyper-methylated during serrated carcinogenesis, from the early SSA/P lesion through the later cancer phases of neoplasia development. We queried the loci hyper-methylated in serrated cancers within our rightsided SSA/Ps from the New Hampshire Colonoscopy Registry, using the Illumina Infinium Human Methylation 450 k panel to comprehensively assess …

Transactivation Of The Estrogen Receptor Promoter By Brca1, William B. Archey, Bradley A. Arrick

Dartmouth Scholarship

Background: Absence of the estrogen receptor-α (ER) is perhaps the most distinctive pathological feature of breast cancers arising in women who inherit a mutation in BRCA1. Two hypotheses, not necessarily mutually exclusive, exist in the literature that describe mechanisms of ER transcriptional repression in breast cancer. One hypothesis suggests that methylation of cytosine–guanine dinucleotides (CpGs) primarily mediates repression, while the other maintains that transcriptional control is mediated by certain positive and negative promoter elements.

Methods: To determine if wild type BRCA1 could induce activity of the ER promoter, we performed a series of tran- sient transfections with ER promoter segments …

Boosting Of Hiv Envelope Cd4 Binding Site Antibodies With Long Variable Heavy Third Complementarity Determining Region In The Randomized Double Blind Rv305 Hiv-1 Vaccine Trial, David Easterhoff, M. Anthony Moody, Daniela Fera, Hao Cheng, Margaret Ackerman

Dartmouth Scholarship

The canary pox vector and gp120 vaccine (ALVAC-HIV and AIDSVAX B/E gp120) in the RV144 HIV-1 vaccine trial conferred an estimated 31% vaccine efficacy. Although the vaccine Env AE.A244 gp120 is antigenic for the unmutated common ancestor of V1V2 broadly neutralizing antibody (bnAbs), no plasma bnAb activity was induced. The RV305 (NCT01435135) HIV-1 clinical trial was a placebo-controlled randomized double-blinded study that assessed the safety and efficacy of vaccine boosting on B cell repertoires. HIV-1- uninfected RV144 vaccine recipients were reimmunized 6–8 years later with AIDSVAX B/E gp120 alone, ALVAC-HIV alone, or a combination of ALVAC-HIV and AIDSVAX B/E gp120 …