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Recent documents in eScholarship@UMMS
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Distal and Proximal Religiosity as Protective Factors for Adolescent and Emerging Adult Alcohol Use

Tue, 09/22/2015 - 12:31pm

Data from emerging adults (ages 18-29, N = 900) in the National Comorbidity Survey Replication Study was used to examine the influence of childhood and emerging adult religiosity and religious-based decision-making, and childhood adversity, on alcohol use. Childhood religiosity was protective against early alcohol use and progression to later abuse or dependence, but did not significantly offset the influence of childhood adversity on early patterns of heavy drinking in adjusted logistic regression models. Religiosity in emerging adulthood was negatively associated with alcohol use disorders. Protective associations for religiosity varied by gender, ethnicity and childhood adversity histories. Higher religiosity may be protective against early onset alcohol use and later development of alcohol problems, thus, should be considered in prevention programming for youth, particularly in faith-based settings. Mental health providers should allow for integration of clients' religiosity and spirituality beliefs and practices in treatment settings if clients indicate such interest.

Sequence-dependent off-target inhibition of TLR7/8 sensing by synthetic microRNA inhibitors

Tue, 09/22/2015 - 12:31pm

Anti-microRNA (miRNA) oligonucleotides (AMOs) with 2'-O-Methyl (2'OMe) residues are commonly used to study miRNA function and can achieve high potency, with low cytotoxicity. Not withstanding this, we demonstrate the sequence-dependent capacity of 2'OMe AMOs to inhibit Toll-like receptor (TLR) 7 and 8 sensing of immunostimulatory RNA, independent of their miRNA-targeting function. Through a screen of 29 AMOs targeting common miRNAs, we found a subset of sequences highly inhibitory to TLR7 sensing in mouse macrophages. Interspecies conservation of this inhibitory activity was confirmed on TLR7/8 activity in human peripheral blood mononuclear cells. Significantly, we identified a core motif governing the inhibitory activity of these AMOs, which is present in more than 50 AMOs targeted to human miRNAs in miRBaseV20. DNA/locked nucleic acids (LNA) AMOs synthesized with a phosphorothioate backbone also inhibited TLR7 sensing in a sequence-dependent manner, demonstrating that the off-target effects of AMOs are not restricted to 2'OMe modification. Taken together, our work establishes the potential for off-target effects of AMOs on TLR7/8 function, which should be taken into account in their therapeutic development and in vivo application.

The Antioxidant Activity and Their Major Antioxidant Compounds from Acanthopanax senticosus and A. koreanum

Tue, 09/22/2015 - 12:31pm

The antioxidant activity and chlorogenic acid and caffeic acid contents were investigated from different parts of Acanthopanax senticosus and A. koreanum. Antioxidant activity was assessed by various in vitro assays such as DPPH, ABTS, FRAP, reducing power assays and ORAC, and the chlorogenic acid and caffeic acid were validated by HPLC chromatography. Among the various extracts, the fruit extracts of A. senticosus and A. koreanum exhibited strongest antioxidant activities including ABTS, FRAP, reducing power and ORAC, however, strongest DPPH radical scavenging activity was observed from the leaf extract of A. senticosus. In addition, the antioxidant activities of various extracts were correlated with total phenolic and proanthocyanidin contents. The major phenolic contents from various parts of these plants observed that leaf extract of A. senticosus expressed higher levels of chlorogenic acid (14.86 mg/dry weigh g) and caffeic acid (3.09 mg/dry weigh g) than other parts. Therefore, these results suggest that the leaf of A. senticosus may be an excellent natural source for functional foods and pharmaceutical agents, and the validated method was useful for the quality control of A. senticosus.

Local sequence assembly reveals a high-resolution profile of somatic structural variations in 97 cancer genomes

Tue, 09/22/2015 - 12:31pm

Genomic structural variations (SVs) are pervasive in many types of cancers. Characterizing their underlying mechanisms and potential molecular consequences is crucial for understanding the basic biology of tumorigenesis. Here, we engineered a local assembly-based algorithm (laSV) that detects SVs with high accuracy from paired-end high-throughput genomic sequencing data and pinpoints their breakpoints at single base-pair resolution. By applying laSV to 97 tumor-normal paired genomic sequencing datasets across six cancer types produced by The Cancer Genome Atlas Research Network, we discovered that non-allelic homologous recombination is the primary mechanism for generating somatic SVs in acute myeloid leukemia. This finding contrasts with results for the other five types of solid tumors, in which non-homologous end joining and microhomology end joining are the predominant mechanisms. We also found that the genes recursively mutated by single nucleotide alterations differed from the genes recursively mutated by SVs, suggesting that these two types of genetic alterations play different roles during cancer progression. We further characterized how the gene structures of the oncogene JAK1 and the tumor suppressors KDM6A and RB1 are affected by somatic SVs and discussed the potential functional implications of intergenic SVs.

Identifying, Targeting, and Exploiting a Common Misfolded, Toxic Conformation of SOD1 in ALS: A Dissertation

Mon, 09/21/2015 - 2:35pm

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by a loss of voluntary movement over time, leading to paralysis and death. While 10% of ALS cases are inherited or familial (FALS), the majority of cases (90%) are sporadic (SALS) with unknown etiology. Approximately 20% of FALS cases are genetically linked to a mutation in the anti-oxidizing enzyme, superoxide dismutase (SOD1). SALS and FALS are clinically indistinguishable, suggesting a common pathogenic mechanism exists for both types. Since such a large number of genetic mutations in SOD1 result in FALS (>170), it is reasonable to suspect that non-genetic modifications to SOD1 induce structural perturbations that result in ALS pathology as well. In fact, misfolded SOD1 lacking any genetic mutation was identified in end stage spinal cord tissues of SALS patients using misfolded SOD1-specific antibodies. In addition, this misfolded WT SOD1 found in SALS tissue inhibits axonal transport in vitro, supporting the notion that misfolded WT SOD1 exhibits toxic properties like that of FALS-linked SOD1. Indeed, aberrant post-translational modifications, such as oxidation, cause WT SOD1 to mimic the toxic properties of FALS-linked mutant SOD1. Based on these data, I hypothesize that modified, misfolded forms of WT SOD1 contribute to SALS disease progression in a manner similar to FALS linked mutant SOD1 in FALS. The work presented in this dissertation supports this hypothesis. Specifically, one common misfolded form of SOD1 is defined and exposure of this toxic region is shown to enhance SOD1 toxicity. Preventing exposure, or perhaps stabilization, of this “toxic” region is a potential therapeutic target for a subset of both familial and sporadic ALS patients. Further, the possibility of exploiting this misfolded SOD1 species as a biomarker is explored. For example, an over-oxidized SOD1 species was identified in peripheral blood mononuclear cells (PBMCs) from SALS patients that is reduced in controls. Moreover, 2-dimensional gel electrophoresis revealed a more negatively charged species of SOD1 in PBMCs of healthy controls greatly reduced in SALS patients. This species is hypothesized to be involved in the degradation of SOD1, further implicating both misfolded SOD1 and altered protein homeostasis in ALS pathogenesis.

Yeast Upf1 Associates With RibosomesTranslating mRNA Coding Sequences Upstream of Normal Termination Codons: A Dissertation

Mon, 09/21/2015 - 2:35pm

Nonsense-mediated mRNA decay (NMD) specifically targets mRNAs with premature translation termination codons for rapid degradation. NMD is a highly conserved translation-dependent mRNA decay pathway, and its core Upf factors are thought to be recruited to prematurely terminating mRNP complexes, possibly through the release factors that orchestrate translation termination. Upf1 is the central regulator of NMD and recent studies have challenged the notion that this protein is specifically targeted to aberrant, nonsense-containing mRNAs. Rather, it has been proposed that Upf1 binds to most mRNAs in a translation-independent manner. In this thesis, I investigated the nature of Upf1 association with its substrates in the yeast Saccharomyces cerevisiae. Using biochemical and genetic approaches, the basis for Upf1 interaction with ribosomes was evaluated to determine the specificity of Upf1 association with ribosomes, and the extent to which such binding is dependent on prior association of Upf1’s interacting partners. I discovered that Upf1 is specifically associated with Rps26 of the 40S ribosomal subunit, and that this association requires the N-terminal Upf1 CH domain. In addition, using selective ribosome profiling, I investigated when during translation Upf1 associates with ribosomes and showed that Upf1 binding was not limited to polyribosomes that were engaged in translating NMD substrate mRNAs. Rather, Upf1 associated with translating ribosomes on most mRNAs, binding preferentially as ribosomes approached the 3’ ends of open reading frames. Collectively, these studies provide new mechanistic insights into NMD and the dynamics of Upf1 during translation.

Molecular Pathways Mediating Glial Responses during Wallerian Degeneration: A Dissertation

Mon, 09/21/2015 - 2:35pm

Glia are the understudied brain cells that perform many functions essential to maintain nervous system homeostasis and protect the brain from injury. If brain damage occurs, glia rapidly adopt the reactive state and elicit a series of cellular and molecular events known as reactive gliosis, the hallmark of many neurodegenerative diseases. However, the molecular pathways that trigger and regulate this process remain poorly defined. The fruit fly Drosophila melanogaster has glial cells that are strikingly similar to mammalian glia, and which also exhibit reactive responses after neuronal injury. By exploiting its powerful genetic toolbox, we are uniquely positioned to identify the genes that activate and execute glial responses to neuronal injury in vivo. In this dissertation, I use Wallerian degeneration in Drosophila as a model to characterize molecular pathways responsible for glia to recognize neural injury, become activated, and ultimately engulf and degrade axonal debris. I demonstrate a novel role for the GEF (guanine nucleotide exchange factors) complex DRK/DOS/SOS upstream of small GTPase Rac1 in glial engulfment activity and show that it acts redundantly with previously discovered Crk/Mbc/dCed-12 to execute glial activation after axotomy. In addition, I discovered an exciting new role for the TNF receptor associated factor 4 (TRAF4) in glial response to axon injury. I find that interfering with TRAF4 and the downstream kinase misshapen (msn) function results in impaired glial activation and engulfment of axonal debris. Unexpectedly, I find that TRAF4 physically associates with engulfment receptor Draper – making TRAF4 only second factor to bind directly to Draper – and show it is essential for Draper-dependent activation of downstream engulfment signaling, including transcriptional activation of engulfment genes via the JNK and STAT transcriptional cascades. All of these pathways are highly conserved from Drosophila to mammals and most are known to be expressed in mouse brain glia, suggesting functional conservation. My work should therefore serve as an excellent starting point for future investigations regarding their roles in glial activation/reactive gliosis in various pathological conditions of the mammalian central nervous system.

Sentinel Lymph Node Biopsy in Elderly Patients with Intermediate Thickness Melanoma: A Masters Thesis

Mon, 09/21/2015 - 2:35pm

Background: A landmark study suggested that wide excision of intermediate-thickness melanoma with sentinel lymph node biopsy (SLNB) and subsequent completion lymph node dissection (CLND) for regional disease may improve prognostication and disease-free survival (DFS) compared with those undergoing wide excision alone. However, these benefits were relatively small and not associated with an improvement in disease-specific survival (DSS). It remains unknown if SLNB and subsequent treatments are beneficial in elderly patients who have a decreased overall (OS) due to other causes.

Methods: Adults ≥ 70 years of age, who underwent surgical intervention for intermediate-thickness cutaneous melanoma from 2000-2013 were identified from a prospectively-maintained database. Clinicopathologic variables measured included age, gender, anatomic site, histologic type, tumor thickness, ulceration, receipt and result of SLNB, completion of CLND, OS, and DFS.

Results: Ninety-one patients underwent excision of an intermediate-thickness melanoma. Forty-nine patients (54%) received a SLNB. Seven of these biopsies (14%) were positive, and five patients went on to receive CLND. Five-year OS was 41% in patients who did not receive SLNB and 52% in patients who did receive SLNB (p=0.11). DFS was similar between groups independent of receipt of SLNB.

Conclusion: Among elderly patients with intermediate-thickness melanoma, patients who received SLNB had similar 5-year OS and DFS compared with those who did not receive SLNB. Routine SLNB for intermediate-thickness melanoma patients may not significantly change outcomes for this age group, and clinical decision-making should consider individual patient comorbidities and goals of care.

Dissecting the Role of a lncRNA and Involvement of <em>Plasmodium</em> Infections in the Innate Immune Response: A Dissertation

Mon, 09/21/2015 - 2:35pm

The innate immune system is a multicomponent response governed by intricate mechanisms of induction, regulation and resolution to elicit antimicrobial defenses. In recent years, the complexity of eukaryotic transcriptomes has become the subject of intense scrutiny and curiosity. It has been established, that RNA polymerase II (RNAPII) transcribes hundreds to thousands of long noncoding RNAs (lncRNAs), often in a stimulus and cell-type specific manner. However, the functional significance of these transcripts has been particularly controversial. While the number of identified lncRNAs is growing, our understanding of how lncRNAs themselves regulate other genes is quite limited. In chapter 2, a novel lncRNA is identified, more specifically, a natural antisense transcript, that mediates the transcription of the pro-inflammatory cytokine IL-1α. Through loss-of-function studies, I report the necessity of this transcript in mediating IL-1α mRNA expression by affecting RNAPII binding to the IL-1α promoter after toll-like receptor signaling. For the first time, I show that IL-1α is regulated at the transcriptional level. As a second independent component of this thesis, we explore the role of the innate immune response after infection by the malaria-causing parasite, Plasmodium berghei ANKA (PbA), and how innate immune components are both beneficial and detrimental to the host depending on when and where inflammation is triggered during infection. We attempt to identify the “malarial toxin” responsible for aberrations in the immune response that is detrimental for disease outcomes and the innate signaling pathways that are involved. Many pathogens induce pathological inflammatory conditions that lead to irreparable homeostatic imbalances and become fatal to the host. Here, type I Interferon signaling is required to dampen parasite load during liver-stage infections, but leads to host mobidity if these pathways are activated in the erythrocytic phase of infection. Together, this thesis provides new insights on how components of the innate immune system are regulated, and how dysregulation of immunity can potentially lead to adverse effects during active infections.

Subtle Controllers: MicroRNAs Drive Pancreatic Tumorigenesis and Progression: A Dissertation

Mon, 09/21/2015 - 2:35pm

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal malignancies in the United States, with an average five-year survival rate of just 6.7%. One unifying aspect of PDAC is mutational activation of the KRAS oncogene, which occurs in over 90% of PDAC. Therefore, inhibiting KRAS function is likely an effective therapeutic strategy for this disease, and current research in our lab and others is focused on identifying downstream effectors of KRAS signaling that may be therapeutic targets. miRNAs are powerful regulators of gene expression that can behave as oncogenes or tumor suppressors. Dysregulation of miRNA expression is commonly observed in human tumors, including PDAC. The mir-17~92 cluster of miRNAs is an established oncogene in a variety of tumor contexts, and members of the mir-17~92 cluster are upregulated in PDAC, but their role has not been explored in vivo. This dissertation encompasses two studies exploring the role of miRNAs in pancreatic tumorigenesis. In Chapter II, I demonstrate that deletion of the mir-17~92 cluster impairs PDAC precursor lesion formation and maintenance, and correlates with reduced ERK signaling in these lesions. mir-17~92 deficient tumors and cell lines are also less invasive, which I attribute to the loss of the miR-19 family of miRNAs. In Chapter III, I find that Dicer heterozygosity inhibits PDAC metastasis, and that this phenotype is attributable to an increased sensitivity to anoikis. Ongoing experiments will determine whether shifts in particular miRNA signatures between cell lines can be attributed to this phenotype. Together these findings illustrate the importance of miRNA biogenesis, and the mir-17~92 cluster in particular, in supporting PDAC development and progression.

Genes Required for Wallerian Degeneration Also Govern Dendrite Degeneration: A Dissertation

Mon, 09/21/2015 - 2:35pm

Neurons comprise the main information processing cells of the nervous system. To integrate and transmit information, neurons elaborate dendritic structures to receive input and axons to relay that information to other cells. Due to their intricate structures, dendrites and axons are susceptible to damage whether by physical means or via disease mechanisms. Studying responses to axon injury, called Wallerian degeneration, in the neuronal processes of Drosophila melanogaster has allowed the identification of genes that are required for injury responses. Screens in Drosophila have identified dsarm and highwire as two genes required for axon degeneration; when these genes are mutated axons fail to degenerate after injury, even when completely cut off from the neuronal cell body. We found that these genes are also required for dendrite degeneration after injury in vivo. Further, we reveal differences between axon and dendrite injury responses using in vivo timelapse recordings and GCaMP indicators of intracellular and mitochondrial calcium transients. These data provide insights into the neuronal responses to injury, and better define novel targets for the treatment of neurodegenerative diseases.

Latent Variable Approaches for Understanding Heterogeneity in Depression: A Dissertation

Mon, 09/21/2015 - 2:35pm

Background: Major depression is one of the most prevalent, disabling, and costly illnesses worldwide. Despite a 400% increase in antidepressant medication use since 1988, fewer than half of treated depression patients experience a clinically meaningful reduction in symptoms and uncertainty exists regarding how to successfully obtain symptom remission. Identifying homogenous subgroups based on clinically observable characteristics could improve the ability to efficiently predict who will benefit from which treatments.

Methods: Latent class analysis and latent transition analysis (LTA) were applied to data from the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study to explore how to efficiently identify subgroups comprised of the multiple dimensions of depression and examine changes in subgroup membership during treatment. The specific aims of this dissertation were to: 1) evaluate latent depression subgroups for men and women prior to antidepressant treatment; 2) examine transitions in these subgroups over 12 weeks of citalopram treatment; and 3) examine differences in functional impairment between women’s depression subgroups throughout treatment.

Results: Four subgroups of depression were identified for men and women throughout this work. Men’s subgroups were distinguished by depression severity and psychomotor agitation and retardation. Severity, appetite changes, insomnia, and psychomotor disturbances characterized women’s subgroups. Psychiatric comorbidities, especially anxiety disorders, were related to increased odds of membership in baseline moderate and severe depression subgroups for men and women. After 12 weeks of citalopram treatment, depression severity and psychomotor agitation were related to men’s chances of improving. Severity and appetite changes were related to women’s likelihood of improving during treatment. When functional impairment was incorporated in LTA models for women, baseline functional impairment levels were related to both depression subgroups at baseline and chances of moving to a different depression subgroup after treatment.

Conclusion: Depression severity, psychomotor disturbances, appetite changes, and insomnia distinguished depression subgroups in STAR*D. Gender, functional impairment, comorbid psychiatric disorders, and likelihood of transitioning to subgroups characterized by symptom improvement differed between these subgroups. The results of this work highlight how relying solely on summary symptom rating scale scores during treatment obscures changes in depression that might be informative for improving treatment response.

Use of Opioids for Pain Management in Nursing Homes: A Dissertation

Mon, 09/21/2015 - 2:35pm

Nursing homes are an essential yet understudied provider of cancer-related care for those with complex health needs. Nine percent of nursing home residents have a cancer diagnosis at admission, and it is estimated that one-third of them experience pain on a daily basis. Although pain management is an essential component of disease treatment, few studies have evaluated analgesic medication use among adults with cancer in this setting. Use of opioids, which are the mainstay of pain management in older adults because of their effectiveness in controlling moderate to severe pain, may be significantly related to coverage by the Medicare Part D prescription drug benefit. However, little is known about Medicare Part D’s effects on opioid use in this patient population. A limited body of evidence also suggests that despite known risks of overdose and respiratory depression in opioid-naïve patients treated with long-acting opioids, use of these agents may be common in nursing homes.

This dissertation examined access to appropriate and effective pain-related health care services among US nursing home residents, with a special focus on those with cancer. Objectives of this dissertation were to: 1) estimate the prevalence, and identify resident-level correlates, of pain and receipt of analgesic medications; 2) use a quasi-experimental research design to examine the relationship between implementation of Medicare Part D and changes in the use of fentanyl patches and other opioids; and 3) to estimate the prevalence, and identify resident-level correlates, of naïve initiation of long-acting opioids. Data on residents’ health status from the Resident Assessment Instrument/Minimum Data Set (versions 2.0 and 3.0) were linked with prescription drug transaction data from a nationwide long-term care pharmacy (January 2005–June 2007) and the Centers for Medicare and Medicaid Services (January–December 2011).

From 2006 to 2007, more than 65% of residents of nursing homes throughout the US with cancer experienced pain (28.3% on a daily basis), among whom 13.5% reported severe pain. More than 17% of these residents who experienced daily pain received no analgesics (95% confidence interval [CI]: 16.0–19.1%), and treatment was negatively associated among those with advanced age, cognitive impairment, feeding tubes, and restraints. These findings coincided with changing patterns in opioid use among residents with cancer, including relatively abrupt 10% and 21% decreases in use of fentanyl patches and other strong opioids, respectively, after the 2006 implementation of Medicare Part D. In the years since Medicare Part D was introduced, some treatment practices in nursing homes have not been concordant with clinical guidelines for pain management among older adults. Among a contemporary population of long-stay nursing home residents with and without cancer, 10.0% (95% CI: 9.4–10.6%) of those who began receiving a long-acting opioid after nursing home admission had not previously received opioid therapy. Odds of naïve initiation of these potent opioids were increased among residents with terminal prognosis, functional impairment, feeding tubes, and cancer.

This dissertation provides new evidence on pharmaceutical management of pain and on Medicare Part D’s impact on opioid use in nursing home residents. Results from this dissertation shed light on nursing home residents’ access to pain-related health care services and provide initial directions for targeted efforts to improve the quality of pain treatment in nursing homes.

Predicting Other Cause Mortality Risk for Older Men with Localized Prostate Cancer: A Dissertation

Mon, 09/21/2015 - 2:35pm

Background: Overtreatment of localized prostate cancer (PCa) is a concern as many men die of other causes prior to experiencing a treatment benefit. This dissertation characterizes the need for assessing other cause mortality (OCM) risk in older men with PCa and informs efforts to identify patients most likely to benefit from definitive PCa treatment.

Methods: Using the linked Surveillance Epidemiology and End Results-Medicare Health Outcomes Survey database, 2,931 men (mean age=75) newly diagnosed with clinical stage T1a-T3a PCa from 1998-2009 were identified. Survival analysis methods were used to compare observed 10-year OCM by primary treatment type. Age and health factors predictive of primary treatment type were assessed with multinomial logistic regression. Predicted mortality estimates from Social Security life tables (recommended for life expectancy evaluation) and two OCM risk estimation tools were compared to observed rates. An improved OCM prediction model was developed fitting Fine and Gray competing risks models for 10-year OCM with age, sociodemographic, comorbidity, activities of daily living, and patient-reported health data as predictors. The tools’ ability to discriminate between patients who died and those who did not was evaluated with Harrell’s c-index (range 0.5-1), which also guided new model selection.

Results: Fifty-four percent of older men with localized PCa underwent radiotherapy while 13% underwent prostatectomy. Twenty-three percent of those treated with radiotherapy and 12% of those undergoing prostatectomy experienced OCM within 10 years of treatment and thus were considered overtreated. Health factors indicative of a shorter life expectancy (increased comorbidity, worse physical health, smoking) had little to no association with radiotherapy assignment but were significantly related to reductions in the likelihood of undergoing prostatectomy. Social Security life tables overestimated mortality risk and discriminated poorly between men who died and those who did not over 10 years (c-index=0.59). Existing OCM risk estimation tools were less likely to overestimate OCM rates and had limited but improved discrimination (c-index=0.64). A risk model developed with self-reported age, Charlson comorbidity index score, overall health (excellent-good/fair/poor), smoking, and marital status predictors had improved discrimination (c-index=0.70).

Conclusions: Overtreatment of older men with PCa is primarily attributable to radiotherapy and may be reduced by pretreatment assessment of mortality-related health factors. This dissertation provides a prognostic model which utilizes a set of five self-reported characteristics that better identify patients likely to die of OCM within 10 years of diagnosis than age and comorbidity-based assessments alone.

Hospital Treatment Practices, 30-Day Hospital Readmissions, and Long-Term Prognosis in Patients Hospitalized with Acute Myocardial Infarction: A Dissertation

Mon, 09/21/2015 - 2:35pm

Background: Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in the U.S. Acute myocardial infarction (AMI), with or without ST-segment elevation, is a common presentation of coronary heart disease and affected more than 800,000 American adults in 2010. The overall goal of this dissertation was to examine decade-long trends in the extent of delay in the receipt of a primary percutaneous coronary intervention (PCI) among patients hospitalized with ST-segment elevation myocardial infarction (STEMI), 30-day hospital readmission rates in patients having survived an AMI, and multiple decade long trends in 1-year post-hospital all-cause mortality, as well as factors associated with these outcomes, among patients hospitalized with AMI.

Methods: Data from the Worcester Heart Attack Study, a population-based chronic disease surveillance project that has been carried out among adult residents of the Worcester, MA, metropolitan area, hospitalized with AMI on a biennial basis from 1975 through 2009 at all medical centers in central MA, were used for this dissertation.

Results: Between 1999 and 2009, among patients hospitalized with STEMI, the likelihood of receiving a primary PCI within 90 minutes after emergency department arrival increased dramatically from 1999/2001 (11.6%) to 2007/2009 (70.5%). Between 1999 and 2009, among hospital survivors of an AMI, the 30-day all-cause rehospitalization rates decreased from 1999/2001 (20.3%) to 2007/2009 (16.7%). The overall cause-specific 30-day rehospitalization rates due to CVD, non-CVD, and AMI were 10.1%, 7.1%, and 1.8%, respectively, during the years under study. Between 1975 and 2009, among hospital survivors for a first AMI, the 1-year post-discharge mortality rates remained relatively stable from 1975-1984 (12.9%) to 1986-1997 (12.5%), but increased during 1999-2009 (15.8%). We identified several demographic, clinical and in-hospital treatment factors associated with an increased risk of failing to receive a primary PCI within 90 minutes after emergency department arrival, 30-day readmissions, and 1-year post-discharge mortality.

Conclusions: Our findings can hopefully lead to the enhanced development of innovative, patient-centered, intervention strategies which can further improve the treatment and transitions of care, as well as short and long-term prognosis, of men and women hospitalized with AMI.

Family Experiences with ICU Bedside Rounds: A Qualitative Descriptive Study: A Dissertation

Mon, 09/21/2015 - 2:31pm

The hospitalization of a family member in an intensive care unit can be a very stressful time for the family. Family bedside rounds is one way for the care team to inform family members, answer questions, and involve them in care decisions. Few studies have examined the experiences of family members with ICU bedside rounds.

A qualitative descriptive study, undergirded by the Family Management Style Framework developed by Knafl and Deatrick (1990, 2003) and Knafl, Deatrick, and Havill (2012), was done at an academic medical center examining families who both participated and did not participate in the family bedside rounds. The majority of families who participated (80%) found the process helpful. One overarching theme emerged from the data of participating families: Making a Connection: Comfort and Confidence. Two major factors influenced how that connection was made: consistency and preparing families for the future. Three types of consistency were identified: consistency with information being shared, consistency about when rounds were being held, and

consistency with being informed of delays. The second major contributing factor was preparing families for the future. When a connection was present, families felt comfortable with the situation. When any of the factors were missing, families described feelings of anger, frustration, and fear. Family members who did not participate described feelings of disappointment and frustration about not having participated.

As healthcare providers, what we say to families matters. They need to be included in decision-making with honest, consistent, easy-to-understand information.

Cathosis: Cathepsins in Particle-induced Inflammatory Cell Death: A Dissertation

Sun, 09/20/2015 - 10:11pm

Sterile particles underlie the pathogenesis of numerous inflammatory diseases. These diseases can often become chronic and debilitating. Moreover, they are common, and include silicosis (silica), asbestosis (asbestos), gout (monosodium urate), atherosclerosis (cholesterol crystals), and Alzeihmer’s disease (amyloid Aβ). Central to the pathology of these diseases is a repeating cycle of particle-induced cell death and inflammation. Macrophages are the key cellular mediators thought to drive this process, as they are especially sensitive to particle-induced cell death and they are also the dominant producers of the cytokine responsible for much of this inflammation, IL-1β. In response to cytokines or microbial cues, IL-1β is synthesized in an inactive form (pro-IL-1β) and requires an additional signal to be secreted as an active cytokine. Although a multimolecular complex, called the NLRP3 inflammasome, controls the activation/secretion of IL-1β (and has been thought to also control cell death) in response to particles in vitro, the in vivo inflammatory response to particles occurs independently of inflammasomes. Therefore, I sought to better understand the mechanisms governing IL-1β production and cell death in response to particles, focusing specifically on the role of lysosomal cathepsin proteases. Inhibitor studies have suggested that one of these proteases, cathepsin B, plays a role in promoting inflammasome activation subsequent to particle-induced lysosomal damage, however genetic models of cathepsin B deficiency have argued otherwise. Through the use of inhibitors, state-of-the-art biochemical tools, and multi-cathepsin-deficient genetic models, I found that multiple redundant cathepsins promote pro-IL-1β synthesis as well as particle-induced NLRP3 activation and cell death. Importantly, I also found that particle-induced cell death does not depend on inflammasomes, suggesting that this may be why inflammasomes do not contribute to particle-induced inflammation in vivo. Therefore, my observations suggest that cathepsins may be multifaceted therapeutic targets involved in the two key pathological aspects of particle-induced inflammatory disease, IL-1β production and cell death.

Role and Regulation of Autophagy During Developmental Cell Death in <i>Drosophila Melanogaster</i>: A Dissertation

Sun, 09/20/2015 - 10:11pm

Autophagy is a conserved catabolic process that traffics cellular components to the lysosome for degradation. Autophagy is required for cell survival during nutrient restriction, but it has also been implicated in programmed cell death. It is associated with several diseases, including cancer. Cancer is a disease characterized by aberrant cell growth and proliferation. To support this growth, the tumor cell often deregulates several metabolic processes, including autophagy. Interestingly, autophagy plays paradoxical roles in tumorigenesis. It has been shown to be both tumor suppressive through cell death mechanisms and tumor promoting through its cytoprotective properties. However, the mechanisms regulating the balance between cell death and cell survival, as well as the metabolic consequences of disrupting this balance, are still poorly understood. Autophagy functions in both cell survival and cell death during the development of Drosophila melanogaster, making it an ideal model for studying autophagy in vivo. My research aimed to better understand the regulation and metabolic contribution of autophagy during cell death in Drosophila. I found that the Ral GTPase pathway, important to oncogenesis, regulates autophagy specifically during cell death in Drosophila larval salivary glands. Contrary to previous studies in mammalian cell culture, Ral is dispensable for autophagy induced during nutrient deprivation suggesting that Ral regulates autophagy in a context-dependent manner. This is the first in vivo evidence of Ral regulating autophagy. I found that disrupting autophagy has an extensive impact on an organism’s metabolism. Additionally, I found that autophagy in degrading tissues is crucial for maintaining the fly’s metabolic homeostasis, and that it may be important for resource allocation amongst tissues. This research highlights the importance of understanding how pathways regulate autophagy in different cell contexts and the metabolic outcomes of manipulating those pathways. This is especially important as we investigate which pathways to target therapeutically in an effort to harness autophagy to promote cell death rather than cell survival.

Causal Inference Methods for Assessing Neurodevelopment in Children Following Prenatal Exposure to Triptan Medications: A Dissertation

Sun, 09/20/2015 - 10:11pm

Background: Migraine headache is a chronic pain condition that affects 20% of women of reproductive age, and is often treated with triptans. Triptans are serotonin 1B, 1D, and 1F receptor agonists that act as vasoconstrictors and inhibitors of the trigeminal cervical complex as well as peripheral neurons; they cross the blood brain barrier and placenta, and as such are plausible neurodevelopmental teratogens. No studies have examined risk of neurodevelopmental problems in children with prenatal triptan exposure. This dissertation had three aims: (1) to examine risk of behavioral problems in children using in the presence of time-varying confounding by concomitant medication use; (2) to examine risk of temperamental, motor, and communication disturbances associated with prenatal triptans exposure, adjusting for unmeasured confounding by migraine type and severity; and (3) to examine changes in neurodevelopment over time associated with prenatal triptan exposure.

Methods: This dissertation used data from the Norwegian Mother and Child Cohort Study, a prospective birth cohort including more than 100,000 women recruited during their first prenatal ultrasound visit. Aims 1 and 3 used marginal structural models to assess the risk of (1) neurodevelopmental problems at age 36 months (Aim 1), or (2) change in risk of neurodevelopmental problems from 18 to 36 months (Aim 3) associated with prenatal triptan exposure. Aim 2 used propensity matching and calibration to adjust for unmeasured confounding by migraine type, severity, and attitudes towards medication use in pregnancy. Neurodevelopmental outcome measures included the Child Behavior Checklist (CBCL), the Emotionality, Activity, and Temperament Scale (EAS), and the Ages and Stages Questionnaire (ASQ). Exposure to triptans was ascertained by self-report.

Results: Prenatal triptan exposure was associated with greater externalizing behavior problems at 18 and 36 months, as well as greater increases in emotionality and activity from 18 to 36 months. We observed no association between triptan exposure and motor skills or communication problems; triptan use during pregnancy was associated with migraine severity but not migraine type, and adjustment for unmeasured migraine characteristics moved effect estimates towards the null.

Conclusions: Prenatal triptan exposure is associated with externalizing-type behaviors and temperament in children, while migraine itself is associated with internalizing-type behaviors and temperament. The use of concomitant medications and the severity of the underlying condition both exerted substantial influence on observed effect estimates, and should be considered in any future studies of triptan medication use in pregnancy.

A Randomized, Double-Blind, Placebo-Controlled Trial of Adjunctive Metformin Therapy in Overweight/Obese Youth with Type 1 Diabetes

Wed, 09/16/2015 - 1:46pm

CONTEXT: Insulin resistance has been proposed as one of the causes of poor glycemic control in overweight/obese youth with type 1 diabetes (T1D). However, the role of adjunctive metformin, an insulin sensitizer, on glycemic control in these patients is unclear.

OBJECTIVE: To compare the effect of metformin vs. placebo on hemoglobin A1c (HbA1c), total daily dose (TDD) of insulin, and other parameters in overweight/obese youth with T1D.

HYPOTHESIS: Adjunctive metformin therapy will improve glycemic control in overweight/obese youth with T1D.

DESIGN, SETTING, AND PARTICIPANTS: A 9-mo randomized, double-blind, placebo controlled trial of metformin and placebo in 28 subjects (13m/15f) of ages 10-20years (y), with HbA1c >8% (64 mmol/mol), BMI >85%, and T1D > 12 months was conducted at a university outpatient facility. The metformin group consisted of 15 subjects (8 m/ 7f), of age 15.0 ± 2.5 y; while the control group was made up of 13 subjects (5m/ 8f), of age 14.5 ± 3.1y. All participants employed a self-directed treat-to-target insulin regimen based on a titration algorithm of (-2)-0-(+2) units to adjust their long-acting insulin dose every 3rd day from -3 mo through +9 mo to maintain fasting plasma glucose (FPG) between 90-120 mg/dL (5.0-6.7 mmol/L). Pubertal maturation was determined by Tanner stage.

RESULTS: Over the course of the 9 months of observation, the between-treatment differences in HbA1c of 0.4% (9.85% [8.82 to 10.88] for placebo versus 9.46% [8.47 to 10.46] for metformin) was not significant (p = 0.903). There were non-significant reduction in fasting plasma glucose (189.4 mg/dL [133.2 to 245.6] for placebo versus 170.5 mg/dL [114.3 to 226.7] for metformin), (p = 0.927); total daily dose (TDD) of short-acting insulin per kg body weight/day(p = 0.936); and the TDD of long-acting insulin per kg body weight per day (1.15 units/kg/day [0.89 to 1.41] for placebo versus 0.90 units/kg/day [0.64 to 1.16] for metformin) (p = 0.221). There was no difference in the occurrence of hypoglycemia between the groups.

CONCLUSIONS: This 9-month RCT of adjunctive metformin therapy in overweight and obese youth with T1D resulted in a 0.4% lower HbA1c value in the metformin group compared to the placebo group.