Diseases Commons^™

Understanding The Role Of Toxs As A Bile Sensing Component Of The Toxrs Virulence Regulatory System In Vibrio Spp., Minje Kim

Dartmouth College Ph.D Dissertations

Pathogenic Vibrio bacteria, such as V. cholerae and V. parahaemolyticus, colonize in the human small intestine to cause severe gastrointestinal disease. During the infection, these bacteria encounter bile salts, antimicrobial cholesterol metabolites secreted into the intestine. Pathogenic Vibrio species have evolved to utilize bile salts as signals to regulate virulence. The signaling depends in part on ToxRS, a conserved co-component transmembrane transcription regulator. ToxRS consists of the transcription factor ToxR and its membrane-tethered binding partner ToxS. ToxS is required for ToxR stability and full transcriptional activity. Although bile salts are known to influence ToxRS-dependent virulence gene expression, the molecular …

Genomic Determinants Of Appetite Regulation And Their Role In Obesity Risk, Timothy J. Renier

Dartmouth College Ph.D Dissertations

Over 40% of US adults and 20% of children live with obesity. It is related to increased risks of diseases including type II diabetes and cancer, is a source of harmful stigma, and impairs child development. Appetitive traits describing patterns of food approach and avoidance behaviors may serve as windows into the underlying pathophysiology of obesity. As both obesity and appetitive traits are heritable, common genetic drivers of obesity may lead to phenotypic obesity through appetitive traits as a disease mechanism. Additionally, GLP-1 receptor agonists (GLP-1RAs) have been shown to exert their profound clinical effects in part by modulating appetite. …

Hierarchical Lineage Tracing To Unravel Mechanisms Of Cancer Treatment Resistance, Rachel Danielle Saxe

Dartmouth College Ph.D Dissertations

Cancer cells adapt to treatment, leading to the emergence of clones that are more aggressive and resistant to anti-cancer therapies. We have a limited understanding of the development of treatment resistance as we lack technologies to map the evolution of cancer under the selective pressure of treatment. To address this, we developed a hierarchical, dynamic lineage tracing method called FLARE (Following Lineage Adaptation and Resistance Evolution). We use this technique to track the progression of acute myeloid leukemia (AML) cell lines through exposure to Cytarabine (AraC), a front-line treatment in AML, in vitro and in vivo. We map distinct cellular …

Strategies To Improve Antibody-Mediated Protection Against Herpes Simplex Virus Infections, Matthew D. Slein

Dartmouth College Ph.D Dissertations

No efficacious vaccine exists for herpes simplex virus and the global burden of disease remains high. Antibodies can serve as potent therapeutics to protect high risk populations such as neonates. Although rare, neonatal HSV (nHSV) infections can result in significant mortality and lifelong neurological morbidity even with antiviral therapy. While HSV-specific maternally derived antibodies significantly reduce the risk of neonatal disease in humans, the mechanisms by which they mediate protection have yet to be described. Using a mouse model of neonatal HSV (nHSV) infections we aimed to determine the mechanisms of antibody-mediated protection using monoclonal antibodies (mAbs) targeting two of …

Mechanisms Of Macrophage Metabolic Activation And Paracrine Wnt Signaling In The Pathogenesis Of Systemic Sclerosis, Emily Ann Morris

Dartmouth College Ph.D Dissertations

Systemic sclerosis (SSc) is a chronic autoimmune disease of unknown etiology. We have previously shown that macrophages (MØs) play a critical role in its pathogenesis; however, the mechanisms driving MØ activation in SSc remain poorly understood. This dissertation investigates the molecular signaling pathways and biochemical mechanisms underlying profibrotic MØ activity in SSc.

First, I identify a novel MØ-specific effect of mycophenolate mofetil (MMF), the standard-of-care treatment for SSc. While MMF is a well characterized lymphostatic, my findings demonstrate that its active metabolite, mycophenolic acid (MPA), is also capable of directly inhibiting myeloid viability and profibrotic MØ activation by suppressing de …

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 …

Dispelling The Malaria-Typhoid Co-Infection Myth In Nigeria. A Literature Review, Olawale Akinola

Dartmouth Library Staff Publications

Malaria and typhoid fever are public health concerns in Nigeria, with high prevalence rates. The perception of a widespread co-infection between these diseases may be misleading, due to limitations in diagnostic methods, particularly the Widal test for typhoid fever. This literature review examines the prevalence of malaria-typhoid co-infection in Nigeria and identifies factors contributing to misdiagnosis, including non-specific symptoms, limited diagnostic resources, and the diagnostic accuracy of tests employed. Additionally, the review discusses the implications of misdiagnosis, such as the overuse of broad-spectrum antibiotics leading to a rising incidence of antimicrobial resistance. Strategies to address this issue are explored, emphasizing …

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 …

Investigating The Role Of Anesthesia In Radiation Therapy, William Walter Daley

ENGS 88 Honors Thesis (AB Students)

Purpose:

Cancer claims 7.6 million lives worldwide annually, affecting millions more. Conventional (CONV) radiation therapy (RT) is a key weapon in the oncological arsenal. A novel mode of radiation delivery, utilizing ultra-high dose rates (UHDR), is associated with enhancing the RT therapeutic ratio by selectively sparing normal tissue without sparing tumor tissue. However, there are many roadblocks to the clinical implementation of UHDR RT —namely the lack of standardization of experimental conditions and the inconsistency of published and unpublished results. This thesis investigates variables that affect preclinical biological outcomes to radiation.

Materials/Methods:

Eight groups of 10 C57BL/6 mice were stratified …

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 …

The Discovery, Characterization, And Engineering Of Autolytic Enzymes As Antimicrobials, Jacob M. Furlon

Dartmouth College Ph.D Dissertations

In an age of rising levels of antibiotic resistance, we are quickly running out of tools to address some of the most virulent and widespread infectious bacteria. One group of enzymes that show significant potential for use as next-generation antibiotics are antimicrobial peptidoglycan hydrolases, often referred to as lysins. These enzymes are responsible for the breakdown of peptidoglycan within the bacterial cell wall, and, when exogenously applied, can result in dramatic destabilization of the cell wall leading to rapid lysis of the bacteria. While phage endolysins have been widely investigated as potential antimicrobials, the therapeutic potential of endogenous autolysins from …

Complement System In Multiple Sclerosis: Its Role In Disease Course And Potential As A Therapeutic Target, Michael R. Linzey

Dartmouth College Ph.D Dissertations

Multiple sclerosis (MS) is a clinically heterogeneous neurological condition characterized by neuroinflammation and neurodegeneration. Relapsing-remitting MS, defined by inflammatory attacks, is the most common initial form of MS and there are currently 23 FDA-approved treatments for these patients. These therapies work primarily by reducing inflammation in the CNS; they do not work well in progressive disease. Therefore, an unmet medical need exists for effective therapeutic options to treat progressive MS (PMS).

In MS, intrathecal immunoglobulins synthesis (IIgS) correlates with disease progression. My goals for this dissertation were to establish the pathological role of IIgS and identify new potential therapeutic …

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 …

Relieving Immune Suppression In The Melanoma Tumor Microenvironment, Gretel Torres Santiesteban

Dartmouth College Ph.D Dissertations

The high immunogenicity of melanoma tumors makes these malignancies an attractive target for immunotherapeutic treatment, as evidenced by the success of ipilimumab and nivolumab. However, most immunotherapeutic approaches have had limited success, partly due to the suppression of innate and adaptive immune responses by tumor-associated macrophages (TAMs) in the tumor microenvironment (TME). TAM redirection may relieve immunosuppression in the TME, directly inhibiting melanoma growth and potentially enhancing the efficacy of additional targeted and immuno-therapies.

We have shown that synthetic oleanane triterpenoid CDDO-Me (or C-Me) enhances immune activation in the melanoma TME by reprogramming TAMs from immunosuppressive to immunostimulatory. CDDO-Me is …

Impacts Of Population Level Environmental Contaminants, Sex Hormones, And Fibroblast Cell Subsets On Systemic Sclerosis (Ssc), Noelle N. Kosarek

Dartmouth College Ph.D Dissertations

Systemic sclerosis (SSc) is a rare autoimmune disease characterized by fibrosis of the skin and internal organs, vascular abnormalities, and autoantibody formation. The etiology of SSc is unknown, though the disease is thought to arise in genetically predisposed individuals after exposure to an environmental factor. There are few FDA approved disease modifying medications available to treat SSc.

The express aims of this dissertation are tripart. First, we aimed to validate a 3D tissue model known as the self-assembled skin equivalent (saSE) model. Second, we sought to describe the geographic distribution of SSc in a US Medicare population to better understand …

Iron Reduction Response And Demographic Differences Between Diabetics And Non-Diabetics With Cardiovascular Disease Entered To A Controlled Clinical Trial, Leo Zacharski, Galina Shamayeva, Bruce Chow

Dartmouth Scholarship

Iron-catalyzed oxygen free radical-induced oxidative stress mediates the pathogenesis of diabetes and cardiovascular disease (CVD). Diabetics (n=473) and non-diabetics (n=804) with CVD entered to a randomized trial of iron (ferritin) reduction by calibrated phlebotomy (www.clinicaltrials.gov, Identifier NCT00032357) had comparable iron measures at entry but diabetics had greater burden of CVD and comorbidities, lower hemoglobin and hematocrit levels, and higher glucose levels than non-diabetics. Entry iron measures were lower in diabetics on hypoglycemic therapy compared to diabetics untreated previously. Diabetics and non-diabetics had comparable iron measures during follow-up. Loess analysis of paired ferritin and hemoglobin, and paired ferritin and glucose levels …

Vista Deficiency Attenuates Antibody-Induced Arthritis And Alters Macrophage Gene Expression In Response To Simulated Immune Complexes, Sabrina Ceeraz, Susan K. Eszterhas, Petra Sergent, David A. Armstrong, Alix Ashare, Thomas Broughton, Li Wang, Dov Pechenick, Christopher M. Burns, Randolph J. Noelle, Matthew P. Vincenti, Roy A. Fava

Dartmouth Scholarship

In addition to activated T cells, the immune checkpoint inhibitor “V domain-containing Ig suppressor of T-cell activation” (VISTA) is expressed by myeloid cell types, including macrophages and neutrophils. The importance of VISTA expression by myeloid cells to antibody-induced arthritis and its potential for relevance in human disease was evaluated. Methods: VISTA was immunolocalized in normal and arthritic human synovial tissue sections and synovial tissue lysates were subjected to western blot analysis. The collagen antibody-induced arthritis model (CAIA) was performed with DBA/1 J mice treated with antibodies against VISTA and with VISTA-deficient mice (V-KO). Total mRNA from arthritic joints, spleens, and …

Lyme Disease: An Influential Outdoor Hazard, Kevin Kang

Dartmouth Undergraduate Journal of Science

Lyme disease is an important, common illness in New England. A relatively new illness, it was discovered about forty years ago in the town of Lyme, Connecticut. Now, it has become the most common vector-transmitted illness in the United States, with over 30,000 cases annually. Lyme disease arises when a bacterium is transmitted to a human via deer tick bite, so those of us involved in outdoor sports are most likely to contract the disease. Inhabitants of New England and the northeastern U.S. are most vulnerable to the disease, as 95% of Lyme Disease cases occur in only 14 out …

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.

Safety And Immunogenicity Of An Inactivated Whole Cell Tuberculosis Vaccine Booster In Adults Primed With Bcg: A Randomized, Controlled Trial Of Dar-901, C. Fordham Von Reyn, Timothy Lahey, Robert D. Arbeit, Bernard Landry, Leway Kailani, Lisa Adams, Brenda Haynes, Todd Mackenzie, Wendy Wieland-Alter, Ruth Connor, Sue Tvaroha, David Hokey, Ann Ginsberg, Richard Waddell

Dartmouth Scholarship

Development of a tuberculosis vaccine to boost BCG is a major international health priority. SRL172, an inactivated whole cell booster derived from a non-tuberculous mycobacterium, is the only new vaccine against tuberculosis to have demonstrated efficacy in a Phase 3 trial. In the present study we sought to determine if a three-dose series of DAR-901 manufactured from the SRL172 master cell bank by a new, scalable method was safe and immunogenic.

The E2f4 Prognostic Signature Predicts Pathological Response To Neoadjuvant Chemotherapy In Breast Cancer Patients, Kenneth M. K. Mark, Frederick S. Varn, Matthew H. Ung, Feng Qian, Chao Cheng

Dartmouth Scholarship

Neoadjuvant chemotherapy is a key component of breast cancer treatment regimens and pathologic complete response to this therapy varies among patients. This is presumably due to differences in the molecular mechanisms that underlie each tumor’s disease pathology. Developing genomic clinical assays that accurately categorize responders from non-responders can provide patients with the most effective therapy for their individual disease. We applied our previously developed E2F4 genomic signature to predict neoadjuvant chemotherapy response in breast cancer. E2F4 individual regulatory activity scores were calculated for 1129 patient samples across 5 independent breast cancer neoadjuvant chemotherapy datasets. Accuracy of the E2F4 signature in …

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 …

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 …

Do The Disc Degeneration And Osteophyte Contribute To The Curve Rigidity Of Degenerative Scoliosis?, Feng Zhu, Hongda Bao, Peng Yan, Shunan Liu, Mike Bao

Dartmouth Scholarship

The factors associated with lateral curve flexibility in degenerative scoliosis have not been well documented. Disc degeneration could result in significant change in stiffness and range of motion in lateral bending films. The osteophytes could be commonly observed in degenerative spine but the relationship between osteophyte formation and curve flexibility remains controversial. The aim of the current study is to clarify if the disc degeneration and osteophyte formation were both associated with curve flexibility of degenerative scoliosis.

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, …

Associations Between Genetic Variants In Mrna Splicing-Related Genes And Risk Of Lung Cancer: A Pathway-Based Analysis From Published Gwass, Yongchu Pan, Hongliang Liu, Yanru Wang, Xiaozheng Kang, Kouros Owzar, Younghun Han

Dartmouth Scholarship

mRNA splicing is an important mechanism to regulate mRNA expression. Abnormal regulation of thisprocess may lead to lung cancer. Here, we investigated the associations of 11,966 single-nucleotide polymorphisms (SNPs) in 206 mRNA splicing-related genes with lung cancer risk by using the summarydata from six published genome-wide association studies (GWASs) of Transdisciplinary Research in Cancerof the Lung (TRICL) (12,160 cases and 16,838 controls) and another two lung cancer GWASs of Harvard University (984 cases and 970 controls) and deCODE (1,319 cases and 26,380 controls). We found that a total of 12 significant SNPs with false discovery rate (FDR) ≤0.05 were mapped …

Potent Single-Domain Antibodies That Arrest Respiratory Syncytial Virus Fusion Protein In Its Prefusion State, Iebe Rossey, Morgan Gilman, Stephanie Kabeche, Koen Sedeyn, Daniel Wrapp

Dartmouth Scholarship

Human respiratory syncytial virus (RSV) is the main cause of lower respiratory tract infections in young children. The RSV fusion protein (F) is highly conserved and is the only viral membrane protein that is essential for infection. The prefusion conformation of RSV F is considered the most relevant target for antiviral strategies because it is the fusion-competent form of the protein and the primary target of neutralizing activity present in human serum. Here, we describe two llama-derived single-domain antibodies (VHHs) that have potent RSV-neutralizing activity and bind selectively to prefusion RSV F with picomolar affinity. Crystal structures of these VHHs …

Association Of Igg4 Response And Autoimmune Pancreatitis With Intraductal Papillary-Mucinous Neoplasms, Amin A. Hedayat, Mikhail Lisovsky, Arief A. Suriawinata

Dartmouth Scholarship

Objectives: Concurrent intraductal papillary-mucinous neoplasm (IPMN) and autoimmune pancreatitis (AIP) was observed in a patient (index case) at our institution. Cases of coincidental IPMN and type 1 AIP and concurrent ductal adenocarcinoma (PDAC) and AIP have been previously reported. In this study we evaluate the hypothesis that IPMN elicits an IgG4 response. Methods: Twenty-one pancreases (including the index case) with IPMN resected at our institution were studied. H&E stained slides were reviewed and blocks of peritumoral pancreas were immunostained with IgG4 to look for IgG4-positive plasma cells. Results: We found evidence of variable IgG4 overexpression in 4/21 (19%) of IPMN. …