The effects of stress on avian gene expression and microbiomes

Organisms must cope with stressors throughout their lifetime. Stressors are broad and come from both intrinsic and extrinsic sources. In this era of rapid global change, exposure to stressors will become more unpredictable and frequent. Thus, it is imperative we begin to understand how organisms respond to these stimuli. Birds are useful models to investigate responses to stress, as they are a diverse taxonomic group encompassing both well studied ecological and laboratory models. Here, I use several bird species and sources of stress to investigate how birds respond from a transcriptomic and microbiome perspective. The first two chapters investigate how infection and androgens impact gene expression of the avian immune system. In Chapter 1, I explore the avian immune transcriptomic response to West Nile virus, a common avian pathogen that has had devastating effects on birds since its emergence in North America. In Chapter 2, I test the Immunocompetence Handicap Hypothesis, which states that androgen-dependent sexually selected traits are costly to produce because androgens are simultaneously immunosuppressive. I used previously published transcriptome data and found support for the hypothesis. In Chapters 3 & 4, I turn my focus to early-life stress and white-throated sparrows (WTSPs). WTSPs exhibit two stable alternative parental care strategies, biparental care and female-biased parental care. In Chapter 3, I show that female-biased care induces a transcriptomic stress response in nestlings. In Chapter 4, I investigate the microbiome of WTSP nestlings and find no differences between individuals raised under the different parental care strategies. However, I do find some evidence of host genetic control of the microbiome. Overall, I have begun to explore how birds cope with various stressors, including infection, androgen induced immunosuppression, and developmental stress. Through primarily gene expression approaches, I uncover the molecular pathways affected by these stimuli. Each chapter will set the stage for future integrative work to explore organismal responses to their environment

Transcriptional response to West Nile virus infection in the zebra finch (Taeniopygia guttata)

West Nile virus (WNV) is a widespread arbovirus that imposes a significant cost to both human and wildlife health. WNV exists in a bird-mosquito transmission cycle in which passerine birds act as the primary reservoir host. As a public health concern, the mammalian immune response to WNV has been studied in detail. Little, however, is known about the avian immune response to WNV. Avian taxa show variable susceptibility to WNV and what drives this variation is unknown. Thus, to study the immune response to WNV in birds, we experimentally infected captive zebra finches (Taeniopygia guttata). Zebra finches provide a useful model, as like many natural avian hosts they are moderately susceptible to WNV and thus provide sufficient viremia to infect mosquitoes. We performed RNAseq in spleen tissue during peak viremia to provide an overview of the transcriptional response. In general, we find strong parallels with the mammalian immune response to WNV, including upregulation of five genes in the Rig-I-like receptor signalling pathway, and offer insights into avian-specific responses. Together with complementary immunological assays, we provide a model of the avian immune response to WNV and set the stage for future comparative studies among variably susceptible populations and species

911 Calls for Emergency Medical Services in Heart Failure: A Descriptive Qualitative Study

Background Heart failure (HF) is a common condition leading to activation of emergency medical services (EMS). Objective The aim of this study was to describe reasons given by persons with HF, family members, or other caregivers for requesting EMS activation during 911 calls. Methods In this descriptive qualitative study, a content analysis was performed on transcribed audio files of 383 EMS requests involving 383 persons with HF in the community. Results One hundred forty-seven calls (38.4%) were placed by the family members, 75 (19.6%) were placed by the patients, 56 (14.6%) were placed by healthcare workers or personnel from living facilities, and the remaining calls (n = 105, 27.4%) were placed by others (eg, friends, neighbors, officers). Three broad categories of symptoms, signs, and events were identified as the reasons for an EMS request. Frequently reported symptoms were breathing problems (55.4%), chest pain (18.3%), and other pain (eg, head, extremities) (16.7%). Signs included decreased consciousness (15.4%), swelling (5.7%), and bleeding (5.0%). The reported events involved falls (8.1%), heart attack (6.3%), hypoxic episodes (6.0%), stroke (5.2%), and post–hospital-discharge complications (4.7%). In most calls (74.9%), multiple reasons were reported and a combination of symptoms, signs, and events were identified. Heart failure diagnosis was mentioned in fewer than 10% of the calls. Conclusions Overall, symptoms and signs of HF exacerbation were common reasons to activate 911 calls. Falls were frequently reported. Under the duress of the emergent situations surrounding the 911 call, callers rarely mentioned the existence of HF. Interventions are needed to guide patients with HF and their family members to promote the management of HF to reduce EMS activation as well as to activate EMS quickly for acute changes in HF conditions

Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.

The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD

Toward a 21st-century health care system: Recommendations for health care reform

The coverage, cost, and quality problems of the U.S. health care system are evident. Sustainable health care reform must go beyond financing expanded access to care to substantially changing the organization and delivery of care. The FRESH-Thinking Project (www.fresh-thinking.org) held a series of workshops during which physicians, health policy experts, health insurance executives, business leaders, hospital administrators, economists, and others who represent diverse perspectives came together. This group agreed that the following 8 recommendations are fundamental to successful reform: 1. Replace the current fee-for-service payment system with a payment system that encourages and rewards innovation in the efficient delivery of quality care. The new payment system should invest in the development of outcome measures to guide payment. 2. Establish a securely funded, independent agency to sponsor and evaluate research on the comparative effectiveness of drugs, devices, and other medical interventions. 3. Simplify and rationalize federal and state laws and regulations to facilitate organizational innovation, support care coordination, and streamline financial and administrative functions. 4. Develop a health information technology infrastructure with national standards of interoperability to promote data exchange. 5. Create a national health database with the participation of all payers, delivery systems, and others who own health care data. Agree on methods to make de-identified information from this database on clinical interventions, patient outcomes, and costs available to researchers. 6. Identify revenue sources, including a cap on the tax exclusion of employer-based health insurance, to subsidize health care coverage with the goal of insuring all Americans. 7. Create state or regional insurance exchanges to pool risk, so that Americans without access to employer-based or other group insurance could obtain a standard benefits package through these exchanges. Employers should also be allowed to participate in these exchanges for their employees' coverage. 8. Create a health coverage board with broad stakeholder representation to determine and periodically update the affordable standard benefit package available through state or regional insurance exchanges

High major histocompatibility complex class I polymorphism despite bottlenecks in wild and domesticated populations of the zebra finch ()

Background Two subspecies of zebra finch, Taeniopygia guttata castanotis and T. g. guttata are native to Australia and the Lesser Sunda Islands, respectively. The Australian subspecies has been domesticated and is now an important model system for research. Both the Lesser Sundan subspecies and domesticated Australian zebra finches have undergone population bottlenecks in their history, and previous analyses using neutral markers have reported reduced neutral genetic diversity in these populations. Here we characterize patterns of variation in the third exon of the highly variable major histocompatibility complex (MHC) class I α chain. As a benchmark for neutral divergence, we also report the first mitochondrial NADH dehydrogenase 2 (ND2) sequences in this important model system. Results Despite natural and human-mediated population bottlenecks, we find that high MHC class I polymorphism persists across all populations. As expected, we find higher levels of nucleotide diversity in the MHC locus relative to neutral loci, and strong evidence of positive selection acting on important residues forming the peptide-binding region (PBR). Clear population differentiation of MHC allele frequencies is also evident, and this may be due to adaptation to new habitats and associated pathogens and/or genetic drift. Whereas the MHC Class I locus shows broad haplotype sharing across populations, ND2 is the first locus surveyed to date to show reciprocal monophyly of the two subspecies. Conclusions Despite genetic bottlenecks and genetic drift, all surveyed zebra finch populations have maintained high MHC Class I diversity. The diversity at the MHC Class I locus in the Lesser Sundan subspecies contrasts sharply with the lack of diversity in previously examined neutral loci, and may thus be a result of selection acting to maintain polymorphism. Given uncertainty in historical population demography, however, it is difficult to rule out neutral processes in maintaining the observed diversity. The surveyed populations also differ in MHC Class I allele frequencies, and future studies are needed to assess whether these changes result in functional immune differences

THE AFFORDABLE CARE ACT AND AMBULANCE RESPONSE TIMES

This study contributes to the literature on supply-side adjustments to insurance expansions by examining the effect of the Affordable Care Act (ACA) on ambulance response times. Exploiting temporal and geographic variation in the implementation of the ACA as well as pre-treatment differences in uninsured rates, we estimate that the expansions of private and Medicaid coverage under the ACA combined to slow ambulance response times by an average of 19%. We conclude that, through extending coverage to individuals who, in its absence, would not have availed themselves of emergency medical services, the ACA added strain to emergency response systems