Medicine and Health Sciences Commons^™

Divergent Antibody Subclass And Specificity Profiles But Not Protective Hla-B Alleles Are Associated With Variable Antibody Effector Function Among Hiv-1 Controllers, Jennifer I. Lai, Anna F. Licht, Anne-Sophie Dugast, Todd Suscovich, Ickwon Choi, Chris Bailey-Kellogg, Galit Alter, Margaret E. Ackerman

Dartmouth Scholarship

Understanding the coordination between humoral and cellular immune responses may be the key to developing protective vaccines, and because genetic studies of long-term HIV-1 nonprogressors have associated specific HLA-B alleles with spontaneous control of viral replication, this subject group presents an opportunity to investigate relationships between arms of the adaptive immune system. Given evidence suggesting that cellular immunity may play a role in viral suppression, we sought to determine whether and how the humoral immune response might vary among controllers. Significantly, Fc-mediated antibody effector functions have likewise been associated with durable viral control. In this study, we compared the effector …

In Vivo Bioluminescence Imaging To Evaluate Systemic And Topical Antibiotics Against Community-Acquired Methicillin-Resistant Staphylococcus Aureus-Infected Skin Wounds In Mice, Yi Guo, Romela Irene Ramos, John S. Cho, Niles P. Donegan, Ambrose L. Cheung, Lloyd S. Miller

Dartmouth Scholarship

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) frequently causes skin and soft tissue infections, including impetigo, cellulitis, folliculitis, and infected wounds and ulcers. Uncomplicated CA-MRSA skin infections are typically managed in an outpatient setting with oral and topical antibiotics and/or incision and drainage, whereas complicated skin infections often require hospitalization, intravenous antibiotics, and sometimes surgery. The aim of this study was to devel

Short Duration Waveforms Recorded Extracellularly From Freely Moving Rats Are Representative Of Axonal Activity, Ashlee A. Robbins, Steven E. Fox, Gregory L. Holmes, Rod C. Scott, Jeremy M. Barry

Dartmouth Scholarship

While extracellular somatic action potentials from freely moving rats have been well characterized, axonal activity has not. We report direct extracellular tetrode recordings of putative axons whose principal feature is a short duration waveform (SDW) with an average peak-trough length less than 179 μs. While SDW recordings using tetrodes have previously been treated as questionable or classified as cells, we hypothesize that they are representative of axonal activity. These waveforms have significantly shorter duration than somatic action potentials, are triphasic and are therefore similar to classic descriptions of microelectrode recordings in white matter and of in vitro action potential propagation …

Prolonged Febrile Seizures Cause Reversible Reductions In White Matter Integrity☆, M. Yoong, K. Seunarine, M. Martinos, R. F. Chin, C. A. Clark, R. C. Scott

Dartmouth Scholarship

Prolonged febrile seizures (PFS) are the commonest cause of childhood status epilepticus and are believed to carry a risk of neuronal damage, in particular to the mesial temporal lobe. This study was designed to determine: i) the effect of prolonged febrile seizures on white matter and ii) the temporal evolution of any changes seen.

33 children were recruited 1 month following PFS and underwent diffusion tensor imaging (DTI) with repeat imaging at 6 and 12 months after the original episode of PFS. 18 age-matched healthy control subjects underwent similar investigations at a single time point. Tract-based spatial statistics (TBSS) was …

Residual Fmri Sensitivity For Identity Changes In Acquired Prosopagnosia, Christopher J. Fox, Giuseppe Iaria, Bradley C. Duchaine, Jason J. S. Barton

Dartmouth Scholarship

While a network of cortical regions contribute to face processing, the lesions in acquired prosopagnosia are highly variable, and likely result in different combinations of spared and affected regions of this network. To assess the residual functional sensitivities of spared regions in prosopagnosia, we designed a rapid event-related functional magnetic resonance imaging (fMRI) experiment that included pairs of faces with same or different identities and same or different expressions. By measuring the release from adaptation to these facial changes we determined the residual sensitivity of face-selective regions-of-interest. We tested three patients with acquired prosopagnosia, and all three of these patients …

Developmental Genes Targeted For Epigenetic Variation Between Twin-Twin Transfusion Syndrome Children, Carmen J. Marsit, Devin C. Koestler, Debra Watson-Smith, Charlotte M. Boney

Dartmouth Scholarship

Background: Epigenetic mechanisms are thought to be critical in mediating the role of the intrauterine environment on lifelong health and disease. Twin-twin transfusion syndrome (TTTS) is a rare condition wherein fetuses share the placenta and develop vascular anastomoses, which allow blood to flow between the fetuses. The unequal flow results in reciprocal hypo- and hypervolemia in the affected twins, striking growth differences and physiologic adaptations in response to this significant stressor. The donor twin in the TTTS syndrome can be profoundly growth restricted and there is likely a nutritional imbalance between the twins. The consequences of TTTS on fetal programming …

Sessile Serrated Adenomas In The Proximal Colon Are Likely To Be Flat, Large And Occur In Smokers, Tarun Rustagi, Priya Rangasamy, Matthew Myers, Melinda Sanders, Haleh Vaziri, George Y. Wu, John W. Birk, Petr Protiva, Joseph C. Anderson

Dartmouth Scholarship

Aim: To examine the epidemiology and the morphology of the proximal sessile serrated adenomas (SSAs).

Methods: We conducted a retrospective study to identify patients with SSAs using a university-based hospital pathology database query from January 2007 to April 2011. Data collected included: age, gender, ethnicity, body mass index, diabetes, smoking, family history of colorectal cancer, aspirin, and statin use. We collected data on morphology of SSAs including site (proximal or distal), size, and endoscopic appearance (flat or protuberant). We also compared proximal SSAs to proximal tubular adenomas detected during same time period.

Spectral Discrimination Of Breast Pathologies In Situ Using Spatial Frequency Domain Imaging, Ashley M. Laughney, Venkataramanan Krishnaswamy, Elizabeth J. Rizzo, Mary C. Schwab, Richard J. Barth, David J. Cuccia, Bruce J. Tromberg, Keith D. Paulsen, Brian W. Pogue, Wendy A. Wells

Dartmouth Scholarship

Introduction: Nationally, 25% to 50% of patients undergoing lumpectomy for local management of breast cancer require a secondary excision because of the persistence of residual tumor. Intraoperative assessment of specimen margins by frozen-section analysis is not widely adopted in breast-conserving surgery. Here, a new approach to wide-field optical imaging of breast pathology in situ was tested to determine whether the system could accurately discriminate cancer from benign tissues before routine pathological processing.

Pouring Salt On A Wound: Pseudomonas Aeruginosa Virulence Factors Alter Na+ And Cl− Flux In The Lung, Alicia E. Ballok, George A. O'Toole

Dartmouth Scholarship

Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen with multiple niches in the human body, including the lung. P. aeruginosa infections are particularly damaging or fatal for patients with ventilator-associated pneumonia, chronic obstructive pulmonary disease, and cystic fibrosis (CF). To establish an infection, P. aeruginosa relies on a suite of virulence factors, including lipopolysaccharide, phospholipases, exoproteases, phenazines, outer membrane vesicles, type III secreted effectors, flagella, and pili. These factors not only damage the epithelial cell lining but also induce changes in cell physiology and function such as cell shape, membrane permeability, and protein synthesis. While such virulence factors are important in …

B Cell Response And Hemagglutinin Stalk-Reactive Antibody Production In Different Age Cohorts Following 2009 H1n1 Influenza Virus Vaccination, Mark Y. Sangster, Jane Baer, Felix W. Santiago, Theresa T. Fitzgerald, Natalia A. Ilyushina

Dartmouth Scholarship

The 2009 pandemic H1N1 (pH1N1) influenza virus carried a swine-origin hemagglutinin (HA) that was closely related to the HAs of pre-1947 H1N1 viruses but highly divergent from the HAs of recently circulating H1N1 strains. Consequently, prior ex- posure to pH1N1-like viruses was mostly limited to individuals over the age of about 60 years. We related age and associated dif- ferences in immune history to the B cell response to an inactivated monovalent pH1N1 vaccine given intramuscularly to subjects in three age cohorts: 18 to 32 years, 60 to 69 years, and >70 years. The day 0 pH1N1-specific hemagglutination inhibition (HAI) …

Dynamic Dual-Tracer Mri-Guided Fluorescence Tomography To Quantify Receptor Density In Vivo, Scott C. Davis, Kimberley S. Samkoe, Kenneth M. Tichauer, Kristian J. Sexton, Jason R. Gunn, Sophie J. Deharvengt, Tayyaba Hasan, Brian W. Pogue

Dartmouth Scholarship

The up-regulation of cell surface receptors has become a central focus in personalized cancer treatment; however, because of the complex nature of contrast agent pharmacokinetics in tumor tissue, methods to quantify receptor binding in vivo remain elusive. Here, we present a dual-tracer optical technique for noninvasive estimation of specific receptor binding in cancer. A multispectral MRI-coupled fluorescence molecular tomography system was used to image the uptake kinetics of two fluorescent tracers injected simultaneously, one tracer targeted to the receptor of interest and the other tracer a nontargeted reference. These dynamic tracer data were then fit to a dual-tracer compartmental model …

Pilot Comparative Effectiveness Study Of Surface Perturbation Treadmill Training To Prevent Falls In Older Adults, Jon D. Lurie, Alexandra B. Zagaria, Dawna M. Pidgeon, Judith L. Forman, Kevin Spratt

Dartmouth Scholarship

Falls are the leading cause of fatal and non-fatal injuries among older adults. Exercise programs appear to reduce fall risk, but the optimal type, frequency, and duration of exercise is unknown. External perturbations such as tripping and slipping are a major contributor to falls, and task-specific perturbation training to enhance dynamic stability has emerged as a promising approach to modifying fall risk. The purpose of this pilot study was 1) to determine the feasibility of conducting a large pragmatic randomized trial comparing a multidimensional exercise program inclusive of the surface perturbation treadmill training (SPTT) to multidimensional exercise alone (Standard PT); …

Anr And Its Activation By Plch Activity In Pseudomonas Aeruginosa Host Colonization And Virulence, Angelyca A. Jackson, Maegan J. Gross, Emily F. Daniels, Thomas H. Hampton, John H. Hammond, Isabelle Vallet-Gely, Simon L. Dove, Bruce A. Stanton, Deborah A. Hogan

Dartmouth Scholarship

Pseudomonas aeruginosa hemolytic phospholipase C (PlcH) degrades phosphatidylcholine (PC), an abundant lipid in cell membranes and lung surfactant. A ΔplcHR mutant, known to be defective in virulence in animal models, was less able to colonize epithelial cell monolayers and was defective in biofilm formation on plastic when grown in lung surfactant. Microarray analyses found that strains defective in PlcH production had lower levels of Anr-regulated transcripts than the wild type. PC degradation stimulated the Anr regulon in an Anr-dependent manner under conditions where Anr activity was submaximal because of the presence of oxygen. Two PC catabolites, choline and glycine …

A Systematic Review Of Ptsd Prevalence And Trajectories In Dsm-5 Defined Trauma Exposed Populations: Intentional And Non-Intentional Traumatic Events, Patcho N. Santiago, Robert J. Ursano, Christine L. Gray, Robert S. Pynoos, David Spiegel, Roberto Lewis-Fernandez, Matthew Friedman, Carol S. Fullerton

Dartmouth Scholarship

Objective: We conducted a systematic review of the literature to explore the longitudinal course of PTSD in DSM-5-defined trauma exposed populations to identify the course of illness and recovery for individuals and populations experiencing PTSD.

Methods: We reviewed the published literature from January 1, 1998 to December 31, 2010 for longitudinal studies of directly exposed trauma populations in order to: (1) review rates of PTSD in the first year after a traumatic event; (2) examine potential types of proposed DSM-5 direct trauma exposure (intentional and non-intentional); and (3) identify the clinical course of PTSD (early onset, later onset, chronicity, remission, …

Neuroinflammation And Psychiatric Illness, Souhel Najjar, Daniel M. Pearlman, Kenneth Alper, Amanda Najjar, Orrin Devinsky

Dartmouth Scholarship

Multiple lines of evidence support the pathogenic role of neuroinflammation in psychiatric illness. While systemic autoimmune diseases are well-documented causes of neuropsychiatric disorders, synaptic autoimmune encephalitides with psychotic symptoms often go under-recognized. Parallel to the link between psychiatric symptoms and autoimmunity in autoimmune diseases, neuroimmunological abnormalities occur in classical psychiatric disorders (for example, major depressive, bipolar, schizophrenia, and obsessive-compulsive disorders). Investigations into the pathophysiology of these conditions traditionally stressed dysregulation of the glutamatergic and monoaminergic systems, but the mechanisms causing these neurotransmitter abnormalities remained elusive. We review the link between autoimmunity and neuropsychiatric disorders, and the human and experimental evidence …

Feasibility Of Tomotherapy-Based Image-Guided Radiotherapy To Reduce Aspiration Risk In Patients With Non-Laryngeal And Non-Pharyngeal Head And Neck Cancer, Nam P. Nguyen, Lexie Smith-Raymond, Vincent Vinh-Hung, Paul Vos, Rick Davis, Anand Desai, Thomas Sroka

Dartmouth Scholarship

Purpose: The study aims to assess the feasibility of Tomotherapy-based image-guided radiotherapy (IGRT) to reduce the aspiration risk in patients with non-laryngeal and non-hypopharyngeal cancer. A retrospective review of 48 patients undergoing radiation for non-laryngeal and non-hypopharyngeal head and neck cancers was conducted. All patients had a modified barium swallow (MBS) prior to treatment, which was repeated one month following radiotherapy. Mean middle and inferior pharyngeal dose was recorded and correlated with the MBS results to determine aspiration risk.

Impairment Of Trkb-Psd-95 Signaling In Angelman Syndrome, Cong Cao, Mengia S. Rioult-Pedotti, Paolo Migani, Crystal J. Yu, Rakesh Tiwari, Keykavous Parang, Mark R. Spaller

Dartmouth Scholarship

Angelman syndrome (AS) is a neurodevelopment disorder characterized by severe cognitive impairment and a high rate of autism. AS is caused by disrupted neuronal expression of the maternally inherited Ube3A ubiquitin protein ligase, required for the proteasomal degradation of proteins implicated in synaptic plasticity, such as the activity-regulated cytoskeletal-associated protein (Arc/Arg3.1). Mice deficient in maternal Ube3A express elevated levels of Arc in response to synaptic activity, which coincides with severely impaired long-term potentiation (LTP) in the hippocampus and deficits in learning behaviors. In this study, we sought to test whether elevated levels of Arc interfere with brain-derived neurotrophic factor (BDNF) …

Incomplete Polyp Resection During Colonoscopy—Results Of The Complete Adenoma Resection (Care) Study, Heiko Pohl, Amitabh Srivastava, Steve P. Bensen, Peter Anderson, Richard I. Rothstein, Stuart R. Gordon, L Campbell Levy, Arifa Toor, Todd A. Mackenzie, Thomas Rosch, Douglas J. Robertson

Dartmouth Scholarship

Although the adenoma detection rate is used as a measure of colonoscopy quality, there are limited data on the quality of endoscopic resection of detected adenomas. We determined the rate of incompletely resected neoplastic polyps in clinical practice.We performed a prospective study on 1427 patients who underwent colonoscopy at 2 medical centers and had at least 1 nonpedunculated polyp (5-20 mm). After polyp removal was considered complete macroscopically, biopsies were obtained from the resection margin. The main outcome was the percentage of incompletely resected neoplastic polyps (incomplete resection rate [IRR]) determined by the presence of neoplastic tissue in post-polypectomy biopsies. …

Characterization Of Brer Interaction With The Bile Response Promoters Breab And Brer In Vibrio Cholerae, Francisca A. Cerda-Maira, Gabriela Kovacikova, Brooke A. Jude, Karen Skorupski, Ronald Taylor

Dartmouth Scholarship

The Vibrio cholerae BreR protein is a transcriptional repressor of the breAB efflux system operon, which encodes proteins involved in bile resistance. In a previous study (F. A. Cerda-Maira, C. S. Ringelberg, and R. K. Taylor, J. Bacteriol. 190:7441-7452, 2008), we used gel mobility shift assays to determine that BreR binds at two independent binding sites at the breAB promoter and a single site at its own promoter. Here it is shown, by DNase I footprinting and site-directed mutagenesis, that BreR is able to bind at a distal and a proximal site in the breAB promoter. However, only one of …