Astrocytic uptake of GABA through GABA transporters (GATs) is an important mechanism regulating excitatory/inhibitory balance in the nervous system; however, mechanisms by which astrocytes regulate GAT levels are undefined. We found that at mid-pupal stages the Drosophila melanogaster CNS neuropil was devoid of astrocyte membranes and synapses. Astrocyte membranes subsequently infiltrated the neuropil coordinately with synaptogenesis, and astrocyte ablation reduced synapse numbers by half, indicating that Drosophila astrocytes are pro-synaptogenic. Shortly after synapses formed in earnest, GAT was upregulated in astrocytes. Ablation or silencing of GABAergic neurons or disruption of metabotropic GABA receptor 1 and 2 (GABA(B)R1/2) signaling in astrocytes led to a decrease in astrocytic GAT. Notably, developmental depletion of astrocytic GABA(B)R1/2 signaling suppressed mechanosensory-induced seizure activity in mutants with hyperexcitable neurons. These data reveal that astrocytes actively modulate GAT expression via metabotropic GABA receptor signaling and highlight the importance of precise regulation of astrocytic GAT in modulation of seizure activity.
rAAV-Mediated Gene Transfer For Study of Pathological Mechanisms and Therapeutic Intervention in Canavan's Disease: A Dissertation
Canavan’s Disease is a fatal Central Nervous System disorder caused by genetic defects in the enzyme – aspartoacylase and currently has no effective treatment options. We report additional phenotypes in a stringent preclinical aspartoacylase knockout mouse model. Using this model, we developed a gene therapy strategy with intravenous injections of the aspartoacylase gene packaged in recombinant adeno associated viruses (rAAVs). We first investigated the CNS gene transfer abilities of rAAV vectors that can cross the blood-brain-barrier in neonatal and adult mice and subsequently used different rAAV serotypes such as rAAV9, rAAVrh.8 and rAAVrh.10 for gene replacement therapy. A single intravenous injection rescued lethality, extended survival and corrected several disease phenotypes including motor dysfunctions. For the first time we demonstrated the existence of a therapeutic time window in the mouse model. In order to limit off-target effects of viral delivery we employed a synthetic strategy using microRNA mediated posttranscriptional detargeting to restrict rAAV expression in the CNS. We followed up with another approach to limit peripheral tissue distribution. Strikingly, we demonstrate that intracerebroventricular administration of a 50-fold lower vectors dose can rescue lethality and extend survival but not motor functions. We also study the contributions of several peripheral tissues in a primarily CNS disorder and examine several molecular attributes behind pathogenesis of Canavan’s disease using primary neural cell cultures. In summary, this thesis describes the potential of novel rAAV-mediated gene replacement therapy in Canavan’s disease and the use of rAAVs as a tool to tease out its pathological mechanism.
Characterization of Innate Immune Pathways in DNA Vaccine-Induced, Antigen-Specific Immune Responses: A Dissertation
A major advantage of DNA vaccination is the ability to induce both humoral and cellular immune responses. DNA vaccines are currently used in veterinary medicine, but their tendency to display low immunogenicity in humans has hindered their usage, despite excellent tolerability and safety profiles. Various approaches have been used to improve the immunogenicity of DNA vaccines. Recent human study data re-established the value of DNA vaccines, especially in priming high-level antigen-specific antibody responses. Data suggests that innate immune responses to the DNA vaccine plasmid itself contribute to the immunogenicity of DNA vaccines, however the underlying mechanisms responsible remain unclear. In this dissertation, we investigate the role of innate immunity in shaping antigen-specific adaptive immune responses following DNA vaccination.
The current belief is that the cytosolic DNA sensing pathways govern DNA vaccine immunogenicity. To date, only the type I interferon inducing STING/TBK1 regulatory pathway has been identified as required for DNA vaccine immunogenicity. Surprisingly, neither the upstream receptor nor the downstream signaling molecules in this pathway have been characterized. I therefore investigated a candidate cytosolic DNA receptor, as well as the downstream transcription factors required for generation of antigen-specific immune responses. Additionally, the effects of pro-inflammatory signaling on DNA vaccine immunogenicity have yet to be comprehensively studied. Previous studies have only provided indirect evidence for the role of inflammatory v signaling in DNA vaccination. As such, I also investigated the role of the DNA sensing AIM2 inflammasome in DNA vaccination. My data indicates that AIM2 is a key modulator in DNA vaccination via a previously unrecognized connection to type I interferon. Importantly, this marks the first time a DNA vaccine sensor has been identified.
Of note, this dissertation represents a departure from many published works in the field. Whereas previous studies have mostly utilized model antigens and only focused on the adaptive immune responses generated, I analyzed the effects on innate immunity as well. Using various innate gene knockout murine models, I quantified antigen-specific humoral and T cell responses, as well as serum cytokine and chemokines following immunization with a clinically relevant DNA vaccine. Overall, this data provides a basis for understanding the mechanisms of DNA vaccination, allowing for the design of more effective vaccines.
Role of Mycobacterium Tuberculosis-Induced Necrotic Cell Death of Macrophages in the Pathogenesis of Pulmonary Tuberculosis: A Dissertation
Mycobacterium tuberculosis, the causative agent of tuberculosis, can manipulate host cell death pathways as virulent strains inhibit apoptosis to protect its replication niche and induce necrosis as a mechanism of escape. In vitro studies revealed that similar to lytic viruses, M. tuberculosis has the ability to induce cytolysis in macrophages when it reaches an intracellular burden of ~25 bacilli. Base on this finding, we proposed the burst size hypothesis that states when M. tuberculosis invades a macrophage at a low multiplicity of infection it replicates to a burst size triggering necrosis to escape the cell and infect naïve nearby phagocytes, propagating the spread of infection. The first part of this study investigated if the in vitro observations of M. tuberculosis cytolysis were relevant to cell death of infected phagocytes during pulmonary tuberculosis in vivo. Mice infected with a low dose of M. tuberculosis revealed during TB disease, the major host cell shifted from one type of phagocyte to another. Enumeration of intracellular bacilli from infected lung cells revealed the predictions of the hypothesis were confirmed by the distribution of bacillary loads across the population of infected phagocytes. Heavily burdened cells appeared nonviable sharing distinctive features similar to infected macrophages from in vitro studies. Collectively, the data indicates that M. tuberculosis triggers necrosis in mononuclear cells when its number reaches the threshold burst size.
The previous study showed during the period of logarithmic bacterial expansion, neutrophils were the primary host cell for M. tuberculosis coinciding with the timeframe of the highest rate of burst size necrosis. The second part of this study examined this link by infecting mice with one of four different M. tuberculosis strains ranging in virulence. Mice infected with the most virulent strain had the highest bacterial burden and elicited the greatest number of infected neutrophils with the most extensive lung inflammation and greater accounts of cell death. Treating these mice with a bacteriostatic agent decreased the bacterial load and infected neutrophils in a dose-dependent manner indicating necrosis induced by virulent M. tuberculosis recruited neutrophils to the lungs. Infected neutrophils can serve as a biomarker in tuberculosis as evidenced by poorly controlled infection and increased severity of lung immune pathology.
CD8+ T cell differentiation is a complex process that requires integration of signals from the TCR, co-stimulatory molecules and cytokines. Ligation of the peptide-MHC complex with the cognate TCR initiates a downstream signaling cascade of which the IL-2 inducible T-cell kinase (ITK) is a key component. Loss of ITK results in a measured reduction in T cell activation. Consequently, Itk deficient mice have defects in thymic selection, CD8+ T cell expansion and differentiation in response to virus infections, and generate a unique population of innate-like CD8+ T cells. The mechanisms that translate TCR and ITK-derived signals into distinct gene transcription programs that regulate CD8+ T cell differentiation are not defined. Our microarray screen identified IRF4 as a potential transcription factor mediating the differentiation of innate-like T cells, and antiviral CD8+ T cell in response to acute and chronic LCMV infections.
Innate-like CD8+ T cells are characterized by their high expression of CD44, CD122, CXCR3, and the transcription factor Eomesodermin (Eomes). One component of this altered development is a non-CD8+ T cell-intrinsic role for IL-4. We show that IRF4 expression is induced upon TCR signaling and is dependent on ITK activity. In contrast to WT cells, activation of IRF4-deficient CD8+ T cells leads to rapid and robust expression of Eomes, which is further enhanced by IL-4 stimulation. These data indicate that ITK signaling promotes IRF4 up-regulation following CD8+ T cell activation and that this signaling xii pathway normally suppresses Eomes expression, thereby regulating the differentiation pathway of CD8+ T cells.
ITK deficient mice also have reduced expansion of CD8+ T cells in response to acute LCMV infections. We show that IRF4 is transiently upregulated to differing levels in murine CD8+ T cells, based on the strength of TCR signaling. In turn, IRF4 controls the magnitude of the CD8+ T cell response to acute virus infection in a dose-dependent manner. Furthermore, the expression of key transcription factors such as T cell factor 1 and Eomesodermin are highly sensitive to graded levels of IRF4. In contrast, T-bet expression is less dependent on IRF4 levels and is influenced by the nature of the infection. These data indicate that IRF4 is a key component that translates the strength of TCR signaling into a graded response of virus-specific CD8+ T cells.
The data from these studies indicated a pivotal role of IRF4 in regulating the expression of T-bet and Eomes. During persistent LCMV infections, CD8+ T cells differentiate into T-bethi and Eomeshi subsets, both of which are required for efficient viral control. We show that TCR signal strength regulates the relative expression of T-bet and Eomes in antigen-specific CD8+ T cells by modulating levels of IRF4. Reduced IRF4 expression results in skewing of this ratio in favor of Eomes, leading to lower proportions and numbers of T-bet+ Eomes- precursors and poor control of LCMV Clone 13 infection. Altering this ratio in favor of T-bet xiii restores the differentiation of T-bet+ Eomes- precursors and the protective balance of T-bet to Eomes required for efficient viral control. These data highlight a critical role for IRF4 in regulating protective anti-viral CD8+ T cell responses by ensuring a balanced ratio of T-bet to Eomes, leading to the ultimate control of this chronic viral infection.
Astrocytes densely infiltrate the brain and intimately associate with synaptic structures. In the past 20 years, they have emerged as critical regulators of both synapse assembly and synapse function. During development, astrocytes modulate the formation of new synapses, and later, control refinement of synaptic connections in response to activity dependent cues. In a mature nervous system, astrocytes modulate synapse function through a variety of mechanisms. These include ion buffering, neurotransmitter uptake and the release of molecules that activate synaptic receptors. Through such roles, astrocytes shape the structure and function of neuronal circuits. However, how astrocytes and synapses reciprocally communicate during circuit assembly remains an unanswered question in the field. The vast majority of our understanding of astrocyte biology has come from studies conducted in mammals, where it is challenging to dissect molecular mechanisms with cell type specificity. Drosophila melanogaster is a less established model system for studying astrocyteneuron interactions, but its vast array of genetic tools and rapid life cycle promises great potential for precisely targeted manipulations. My thesis work has utilized Drosophila melanogaster to investigate the reciprocal nature of astrocyte-synapse communication. First, I characterized Drosophila late metamorphosis as a developmental stage in which astrocyte-synapse associations can be studied. My work demonstrates that during this time, when the adult Drosophila nervous system is being assembled, synapse formation relies on the coordinated infiltration of astrocyte membranes into the neuropil. Next, I show that in a reciprocal manner, neural activity can shape astrocyte biology during this time as well and impart long lasting effects on neuronal circuit function. In particular expression of the astrocyte GABA transporter (GAT) is modulated in an activity-dependent manner via astrocytic GABABR1/2 receptor signaling. Inhibiting astrocytic GABABR1/2 signaling strongly suppresses hyperexcitability in a Drosophila seizure model, vii arguing this pathway is important for modulating excitatory/inhibitory balance in vivo. Finally, utilizing the ease of the Drosophila system, I performed a reverse genetic screen to identify additional astrocyte factors involved in modulating excitatory-inhibitory neuronal balance.
The three dimensional structure of the human genome is known to play a critical role in gene function and expression. I used chromosome conformation capture (3C) and 3C-carbon copy (5C) techniques to investigate the three-dimensional structure of the cystic fibrosis transmembrane conductance regulator (CFTR) locus. This is an important disease gene that, when mutated, causes cystic fibrosis. 3C experiments identified four distinct looping elements that contact the CFTR gene promoter only in CFTR-expressing cells. Using 5C, I expanded the region of study to a 2.8 Mb region surrounding the CFTR gene. The 5C study shows 7 clear topologically associating domains (TADs) present at the locus, identical in all five cell lines tested, regardless of gene expression status. CFTR and all its known regulatory elements are contained within one TAD, suggesting TADs play a role in constraining promoters to a local search space. The four looping elements identified in the 3C experiment and confirmed in the 5C experiment were then tested for enhancer activity using a luciferase assay, which showed that elements III and IV could act as enhancers. These elements were tested against a library of human transcription factors in a yeast one-hybrid assay to identify potential binding proteins. Element III gave two strong candidates, TCF4 and LEF1. A literature search supported these transcription factors as playing a role in CFTR gene expression. Overall, this work represents a model locus that can be used to test important questions regarding the role of three dimensional looping on gene expression.
Mindfulness is recognized as an evidence-based practice that can improve a person’s physical and emotional health and well-being. This research project examined the cultural relevance and potential acceptability of mindfulness practices by front-line providers working with a low-income community of color affected by gun homicide.
Association between Smoking and Health Outcomes in Postmenopausal Women Living with Multiple Sclerosis
Background. In multiple sclerosis (MS), symptom management and improved health-related quality of life (HrQOL) may be modified by smoking.
Objective. To evaluate the extent to which smoking is associated with worsened health outcomes and HrQOL for postmenopausal women with MS.
Methods. We identified 251 Women's Health Initiative Observational Study participants with a self-reported MS diagnosis. Using a linear model, we estimated changes from baseline to 3 years for activities of daily living, total metabolic equivalent tasks (MET) hours per week, mental and physical component scales (MCS, PCS) of the SF-36, and menopausal symptoms adjusting for years since menopause and other confounders.
Results. Nine percent were current and 50% past smokers. Age at smoking initiation was associated with significant changes in MCS during menopause. PCS scores were unchanged. While women who had ever smoked experienced an increase in physical activity during menopause, the physical activity levels of women who never smoked declined. Residual confounding may explain this finding. Smoking was not associated with change in menopausal symptoms during the 3-year follow-up.
Conclusion. Smoking was not associated with health outcomes among post-menopausal women with MS.
Autologous stem cell transplant (ASCT) is the standard of care in transplant-eligible multiple myeloma patients and is associated with significant improvement in progression-free survival (PFS), complete remission rates (CR), and overall survival (OS). However, majority of patients eventually relapse, with a median PFS of around 36 months. Relapses are harder to treat and prognosis declines with each relapse. Achieving and maintaining "best response" to initial therapy is the ultimate goal of first-line treatment and sustained CR is a powerful surrogate for extended survival especially in high-risk multiple myeloma. ASCT is often followed by consolidation/maintenance phase to deepen and/or maintain the response achieved by induction and ASCT. Novel agents like thalidomide, lenalidomide, and bortezomib have been used as single agents or in combination. Thalidomide use has been associated with a meaningful improvement in PFS and EFS, however, with substantial side effects. Data with lenalidomide maintenance after-ASCT is favorable, but the optimal duration of lenalidomide maintenance is still unclear. Bortezomib use has been associated with superior outcomes, predominantly in high-risk myeloma patients. Combination regimens utilizing a proteasome inhibitor (i.e., bortezomib) with an immunomodulatory drug (thalidomide or lenalidomide) have provided the best outcomes. This review article serves as a review of the best available evidence in post-ASCT approaches in multiple myeloma.
Treatment of rheumatoid arthritis with marine and botanical oils: an 18-month, randomized, and double-blind trial
Objective. To determine whether a combination of borage seed oil rich in gamma linolenic acid (GLA) and fish oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is superior to either oil alone for treatment of rheumatoid arthritis (RA).
Methods. Patients were randomized into a double-blind, 18-month trial. Mixed effects models compared trends over time in disease activity measures.
Results. No significant differences were observed in changes in disease activity among the three randomized groups. Each group exhibited significant reductions in disease activity (DAS28) at 9 months (fish: -1.56[-2.16, -0.96], borage: -1.33[-1.83, -0.84], combined: -1.18[-1.83, -0.54]) and in CDAI (fish: -16.95[-19.91, -13.98], borage: -11.20[-14.21, -8.19], and combined: -10.31[-13.61, -7.01]). There were no significant differences in change of RA medications among the three groups. Reduced disease activity in study patients was similar to matched patients from an RA registry, and reduction in DMARD use was greater (P < 0.03) in study patients.
Conclusion. All 3 treatment groups exhibited similar meaningful clinical responses after 9 months, improvements which persisted for 18 months, and a response similar to matched patients from an RA registry. Study patients were able to reduce DMARD therapy given in combination with TNF antagonists to a greater extent than registry patients.
This paper is dedicated to the memory of Dr. John T. Sharp, M.D., a pioneer and innovator in the field of musculoskeletal radiology.
Genetic vaccination against experimental infection with myotropic parasite strains of Trypanosoma cruzi
In earlier studies, we reported that a heterologous prime-boost regimen using recombinant plasmid DNA followed by replication-defective adenovirus vector, both containing Trypanosoma cruzi genes encoding trans-sialidase (TS) and amastigote surface protein (ASP) 2, provided protective immunity against experimental infection with a reticulotropic strain of this human protozoan parasite. Herein, we tested the outcome of genetic vaccination of F1 (CB10XBALB/c) mice challenged with myotropic parasite strains (Brazil and Colombian). Initially, we determined that the coadministration during priming of a DNA plasmid containing the murine IL-12 gene improved the immune response and was essential for protective immunity elicited by the heterologous prime-boost regimen in susceptible male mice against acute lethal infections with these parasites. The prophylactic or therapeutic vaccination of resistant female mice led to a drastic reduction in the number of inflammatory infiltrates in cardiac and skeletal muscles during the chronic phase of infection with either strain. Analysis of the electrocardiographic parameters showed that prophylactic vaccination reduced the frequencies of sinus arrhythmia and atrioventricular block. Our results confirmed that prophylactic vaccination using the TS and ASP-2 genes benefits the host against acute and chronic pathologies caused by T. cruzi and should be further evaluated for the development of a veterinary or human vaccine against Chagas disease.
Induction of IL-12 production in human peripheral monocytes by Trypanosoma cruzi Is mediated by glycosylphosphatidylinositol-anchored mucin-like glycoproteins and potentiated by IFN- gamma and CD40-CD40L interactions
Chagas disease, caused by the protozoan parasite Trypanosoma cruzi (T. cruzi), is characterized by immunopathology driven by IFN-gamma secreting Th1-like T cells. T. cruzi has a thick coat of mucin-like glycoproteins covering its surface, which plays an important role in parasite invasion and host immunomodulation. It has been extensively described that T. cruzi or its products-like GPI anchors isolated from GPI-anchored mucins from the trypomastigote life cycle stage (tGPI-mucins)-are potent inducers of proinflammatory responses (i.e., cytokines and NO production) by IFN-gamma primed murine macrophages. However, little is known about whether T. cruzi or GPI-mucins exert a similar action in human cells. We therefore decided to further investigate the in vitro cytokine production profile from human mononuclear cells from uninfected donors exposed to T. cruzi as well as tGPI-mucins. We observed that both living T. cruzi trypomastigotes and tGPI-mucins are potent inducers of IL-12 by human peripheral blood monocytes and this effect depends on CD40-CD40L interaction and IFN-gamma. Our findings suggest that the polarized T1-type cytokine profile seen in T. cruzi infected patients might be a long-term effect of IL-12 production induced by lifelong exposure to T. cruzi tGPI-mucins.
Salmonella outbreaks have been linked to a wide variety of foods, including recent nationwide outbreaks. Guinea pig (Cavia porcellus), also known as cuy or cobayo, has long been a popular delicacy and ceremonial food in the Andean region in South America. This case report describes three family outbreaks of nontyphoidal salmonellosis, each occurring after a meal of guinea pigs. We believe this case report is the first to describe a probable association between the consumption of guinea pig meat and human salmonellosis. Physicians should be aware of the association of Salmonella and the consumption of guinea pigs, given the increasing immigration of people from the Andean region of South America and the increasing travel to this region.
Acceleration of wound healing by alpha-gal nanoparticles interacting with the natural anti-Gal antibody
Application of alpha-gal nanoparticles to wounds and burns induces accelerated healing by harnessing the natural anti-Gal antibody which constitutes ~1% of human immunoglobulins. alpha-gal nanoparticles present multiple alpha-gal epitopes (Galalpha1-3Galbeta1-4GlcNAc-R), the carbohydrate ligand of anti-Gal. Studied alpha-gal nanoparticles were comprised of glycolipids with alpha-gal epitopes, phospholipids, and cholesterol. Binding of anti-Gal to alpha-gal nanoparticles in wounds activates the complement cascade, resulting in formation of chemotactic complement cleavage peptides that induce rapid recruitment of many macrophages. The Fc/Fcgamma receptors interaction between anti-Gal coating alpha-gal nanoparticles and the recruited macrophages activates macrophages to produce cytokines/growth factors that promote wound healing and recruit stem cells. Studies of wound healing by alpha-gal nanoparticles were feasible in alpha1,3galactosyltransferase knockout mice and pigs. In contrast to other nonprimate mammals, these mice and pigs lack the alpha-gal epitope, and thus they are not immunotolerant to it and produce anti-Gal. Treatment of skin wounds and burns with alpha-gal nanoparticles resulted in 40-60% decrease in healing time in comparison with control wounds treated with saline. This accelerated healing is associated with increased recruitment of macrophages and extensive angiogenesis in wounds, faster regrowth of epidermis, and regeneration of the dermis. The accelerated healing further decreases and may completely eliminate fibrosis and scar formation in wounds. Since healing of internal injuries is mediated by mechanisms similar to those in external wound healing, it is suggested that alpha-gal nanoparticles treatment may also improve regeneration and restoration of biological function following internal injuries such as surgical incisions, myocardial ischemia following infarction, and nerve injuries.
Trauma training course: innovative teaching models and methods for training health workers in active conflict zones of Eastern Myanmar
BACKGROUND: Myanmar has struggled through decades of internal conflict, which has negatively impacted the country's health outcomes. Recent government changes have brought hope and reduced conflict. The ethnic minority groups have suffered the brunt of the health consequences and reside in regions that lack health infrastructure, resources, and providers. Due to the chronic lack of healthcare providers within conflict areas, health workers (HWs) have been trained in an effort to fill the void. Research has shown that these non-physician clinicians positively impact health outcomes in developing countries. These HWs are supported by community-based organizations in collaboration with foreign non-governmental organizations. Started in 2000, the trauma training course was developed to meet the educational needs of these HWs.
METHODS: Essential procedures for HWs in conflict zones were identified, and teaching methods were adapted to develop models that were simple, reproducible, cost effective, and able to facilitate effective learning within the limitations of these challenging environments. This paper presents simulation models developed to teach trauma injury evaluation and management in resource-limited settings to HWs.
RESULTS: Material and construction of the models described include breathing, chest, cricothyroidotomy, circulation, wound repair, fracture/dislocation, splinting, fasciotomy/amputation, and an animal model. In 2013, a pre/post test and post-training evaluation were completed, which demonstrated an increase in understanding of the material and satisfaction with the training.
CONCLUSIONS: The simulation models described engage the HWs in clinical skills practice specific to injury management, which builds upon the HWs existing knowledge and facilitates an increased understanding of life-saving procedures. Through observation of the HW performance and HW feedback, these simulation models have increased the understanding of trauma management. Limitations include lack of a graduated learning system for the HWs, logistics, and time constraints. Despite the barriers faced, we feel that this is a necessary program that has reduced morbidity and mortality due to traumatic injury in the geographic areas that the HWs serve. With the changing political environment in Myanmar and the development of peace agreements between the government and the ethnic minority groups, these HWs can be integrated into Myanmar's evolving health system.
BACKGROUND: Many leukemias result from chromosomal rearrangements. The t(8;21) chromosomal translocation produces AML1-ETO, an oncogenic fusion protein that compromises the function of AML1, a transcription factor critical for myeloid cell differentiation. Because of the pressing need for new therapies in the treatment of acute myleoid leukemia, we investigated the genome-wide occupancy of AML1-ETO in leukemic cells to discover novel regulatory mechanisms involving AML-ETO bound genes.
RESULTS: We report the co-localization of AML1-ETO with the N-CoR co-repressor to be primarily on genomic regions distal to transcriptional start sites (TSSs). These regions exhibit over-representation of the motif for PU.1, a key hematopoietic regulator and member of the ETS family of transcription factors. A significant discovery of our study is that genes co-occupied by AML1-ETO and N-CoR (e.g., TYROBP and LAPTM5) are associated with the leukemic phenotype, as determined by analyses of gene ontology and by the observation that these genes are predominantly up-regulated upon AML1-ETO depletion. In contrast, the AML1-ETO/p300 gene network is less responsive to AML1-ETO depletion and less associated with the differentiation block characteristic of leukemic cells. Furthermore, a substantial fraction of AML1-ETO/p300 co-localization occurs near TSSs in promoter regions associated with transcriptionally active loci.
CONCLUSIONS: Our findings establish a novel and dominant t(8;21) AML leukemia signature characterized by occupancy of AML1-ETO/N-CoR at promoter-distal genomic regions enriched in motifs for myeloid differentiation factors, thus providing mechanistic insight into the leukemic phenotype.
Fat-mass and obesity-associated gene polymorphisms and weight gain after risperidone treatment in first episode schizophrenia
BACKGROUND: Obesity induced by antipsychotics severely increases the risk of many diseases and significantly reduces quality of life. Genome Wide Association Studies has identified fat-mass and obesity-associated (FTO) gene associated with obesity. The relationship between the FTO gene and drug-induced obesity is unclear.
METHOD: Two hundred and fifty drug naive, Chinese Han patients with first-episode schizophrenia were enrolled in the study, and genotyped for four single nucleotide polymorphisms (SNPs rs9939609, rs8050136, rs1421085 and rs9930506) by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct sequencing. Body weight and body mass index (BMI) were measured at baseline and six months after risperidone treatment.
RESULTS: At baseline, body weight and BMI of TT homozygotes were lower than those of A allele carriers in rs9939609; body weight of AA homozygotes was higher than those of G allele carriers in rs9930506 (p's < 0.05). After 6 months of risperidone treatment, body weight and BMI of TT homozygotes were lower than those of A allele carriers in rs9939609 (p's < 0.01); body weight and BMI of CC homozygotes were lower than those of A allele carriers in rs8050136 (p's < 0.05); body weight of AA homozygotes was higher than those of G allele carriers in rs9930506 (p's < 0.05). After controlling for age, gender, age of illness onset, disease duration, weight at baseline and education, weight gain of TT homozygotes at 6 months remained to be lower than those of A allele carriers in rs9939609 (p < 0.01); weight gain of CC homozygotes at 6 months was lower than those of A allele carriers in rs8050136 (p = 0.01). Stepwise multiple regression analysis suggested that, among 4 SNPs, rs9939609 was the strongest predictor of weight gain after 6 months of risperidone treatment (p = 0.001).
CONCLUSIONS: The FTO gene polymorphisms, especially rs9939609, seem to be related to weight gain after risperidone treatment in Chinese Han patients with first episode schizophrenia.
Suicide risk in Veterans Health Administration patients with mental health diagnoses initiating lithium or valproate: a historical prospective cohort study
BACKGROUND: Lithium has been reported in some, but not all, studies to be associated with reduced risks of suicide death or suicidal behavior. The objective of this nonrandomized cohort study was to examine whether lithium was associated with reduced risk of suicide death in comparison to the commonly-used alternative treatment, valproate.
METHODS: A propensity score-matched cohort study was conducted of Veterans Health Administration patients (n=21,194/treatment) initiating lithium or valproate from 1999-2008.
RESULTS: Matching produced lithium and valproate treatment groups that were highly similar in all 934 propensity score covariates, including indicators of recent suicidal behavior, but recent suicidal ideation was not able to be included. In the few individuals with recently diagnosed suicidal ideation, a significant imbalance existed with suicidal ideation more prevalent at baseline among individuals initiating lithium than valproate (odds ratio (OR) 1.30, 95% CI 1.09, 1.54; p=0.003). No significant differences in suicide death were observed over 0-365 days in A) the primary intent-to-treat analysis (lithium/valproate conditional odds ratio (cOR) 1.22, 95% CI 0.82, 1.81; p=0.32); B) during receipt of initial lithium or valproate treatment (cOR 0.86, 95% CI 0.46, 1.61; p=0.63); or C) after such treatment had been discontinued/modified (OR 1.51, 95% CI 0.91, 2.50; p=0.11). Significantly increased risks of suicide death were observed after the discontinuation/modification of lithium, compared to valproate, treatment over the first 180 days (OR 2.72, 95% CI 1.21, 6.11; p=0.015).
CONCLUSIONS: In this somewhat distinct sample (a predominantly male Veteran sample with a broad range of psychiatric diagnoses), no significant differences in associations with suicide death were observed between lithium and valproate treatment over 365 days. The only significant difference was observed over 0-180 days: an increased risk of suicide death, among individuals discontinuing or modifying lithium, compared to valproate, treatment. This difference could reflect risks either related to lithium discontinuation or higher baseline risks among lithium recipients (i.e., confounding) that became more evident when treatment stopped. Our findings therefore support educating patients and providers about possible suicide-related risks of discontinuing lithium even shortly after treatment initiation, and the close monitoring of patients after lithium discontinuation, if feasible. If our findings include residual confounding biasing against lithium, however, as suggested by the differences observed in diagnosed suicidal ideation, then the degree of beneficial reduction in suicide death risk associated with active lithium treatment would be underestimated. Further research is urgently needed, given the lack of interventions against suicide and the uncertainties concerning the degree to which lithium may reduce suicide risk during active treatment, increase risk upon discontinuation, or both.
Patient safety incident capture resulting from incident reports: a comparative observational analysis
BACKGROUND: Patient safety incident (PSI) discovery is an essential component of quality improvement. When submitted, incident reports may provide valuable opportunities for PSI discovery. However, little objective information is available to date to quantify or demonstrate this value. The objective of this investigation was to assess how often Emergency Department (ED) incident reports submitted by different sources led to the discovery of PSIs.
METHODS: A standardized peer review process was implemented to evaluate all incident reports submitted to the ED. Findings of the peer review analysis were recorded prospectively in a quality improvement database. A retrospective analysis of the quality improvement database was performed to calculate the PSI capture rates for incident reports submitted by different source groups.
RESULTS: 363 incident reports were analyzed over a period of 18 months; 211 were submitted by healthcare providers (HCPs) and 126 by non-HCPs. PSIs were identified in 108 resulting in an overall capture rate of 31%. HCP-generated reports resulted in a 44% capture rate compared to 10% for non-HCPs (p < 0.001). There was no difference in PSI capture between sub-groups of HCPs and non-HCPs.
CONCLUSION: HCP-generated ED incident reports were much more likely to capture PSIs than reports submitted by non-HCPs. However, HCP reports still led to PSI discovery less than half the time. Further research is warranted to develop effective strategies to improve the utility of incident reports from both HCPs and non-HCPs.