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9 result(s) for "Overman, Rachel"
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Assays for the Evaluation of the Immune Response to Marburg and Ebola Sudan Vaccination—Filovirus Animal Nonclinical Group Anti-Marburg Virus Glycoprotein Immunoglobulin G Enzyme-Linked Immunosorbent Assay and a Pseudovirion Neutralization Assay
Since the discovery of the Marburg virus (MARV) in 1967 and Ebola virus (EBOV) in 1976, there have been over 40 reported outbreaks of filovirus disease with case fatality rates greater than 50%. This underscores the need for efficacious vaccines against these highly pathogenic filoviruses. Due to the sporadic and unpredictable nature of filovirus outbreaks, such a vaccine would likely need to be vetted through the U.S. Food and Drug Administration (FDA), following the Animal Rule or similar European Medicines Agency (EMA) regulatory pathway. Under the FDA Animal Rule, vaccine-induced immune responses correlating with survival of non-human primates (NHPs), or another well-characterized animal model, following lethal challenge, will need to be bridged for human immune response distributions in clinical trials. A correlate of protection has not yet been identified for the filovirus disease, but antibodies, specifically anti-glycoprotein (GP) antibodies, are believed to be critical in providing protection against the filovirus disease following vaccination and are thus a strong candidate for a correlate of protection. Thus, species-neutral methods capable of the detection and bridging of these antibody immune responses, such as methods to quantify anti-GP immunoglobulin G (IgG)-binding antibodies and neutralizing antibodies, are needed. Reported here is the development and qualification of two Filovirus Animal Nonclinical Group (FANG) anti-GP IgG Enzyme-Linked Immunosorbent Assays (ELISAs) to quantify anti-MARV and anti-Sudan virus (SUDV) IgG antibodies in human and NHP serum samples, as well as the development of pseudovirion neutralization assays (PsVNAs) to quantify MARV- and SUDV-neutralizing antibodies in human and NHP serum samples.
Rapid isolation and enrichment of extracellular vesicle preparations using anion exchange chromatography
Extracellular vesicles (EVs) have important roles in physiology, pathology, and more recently have been identified as efficient carriers of therapeutic cargoes. For efficient study of EVs, a single-step, rapid and scalable isolation strategy is necessary. Chromatography techniques are widely used for isolation of biological material for clinical applications and as EVs have a net negative charge, anion exchange chromatography (AIEX) is a strong candidate for column based EV isolation. We isolated EVs by AIEX and compared them to EVs isolated by ultracentrifugation (UC) and tangential flow filtration (TFF). EVs isolated by AIEX had comparable yield, EV marker presence, size and morphology to those isolated by UC and had decreased protein and debris contamination as compared to TFF purified EVs. An improved AIEX protocol allowing for higher flow rates and step elution isolated 2.4*10 11 EVs from 1 litre of cell culture supernatant within 3 hours and removed multiple contaminating proteins. Importantly AIEX isolated EVs from different cell lines including HEK293T, H1299, HCT116 and Expi293F cells. The AIEX protocol described here can be used to isolate and enrich intact EVs in a rapid and scalable manner and shows great promise for further use in the field for both research and clinical purposes.
Spatial transcriptomics reveals novel genes during the remodelling of the embryonic human arterial valves
Abnormalities of the arterial valves, including bicuspid aortic valve (BAV) are amongst the most common congenital defects and are a significant cause of morbidity as well as predisposition to disease in later life. Despite this, and compounded by their small size and relative inaccessibility, there is still much to understand about how the arterial valves form and remodel during embryogenesis, both at the morphological and genetic level. Here we set out to address this in human embryos, using Spatial Transcriptomics (ST). We show that ST can be used to investigate the transcriptome of the developing arterial valves, circumventing the problems of accurately dissecting out these tiny structures from the developing embryo. We show that the transcriptome of CS16 and CS19 arterial valves overlap considerably, despite being several days apart in terms of human gestation, and that expression data confirm that the great majority of the most differentially expressed genes are valve-specific. Moreover, we show that the transcriptome of the human arterial valves overlaps with that of mouse atrioventricular valves from a range of gestations, validating our dataset but also highlighting novel genes, including four that are not found in the mouse genome and have not previously been linked to valve development. Importantly, our data suggests that valve transcriptomes are under-represented when using commonly used databases to filter for genes important in cardiac development; this means that causative variants in valve-related genes may be excluded during filtering for genomic data analyses for, for example, BAV. Finally, we highlight “novel” pathways that likely play important roles in arterial valve development, showing that mouse knockouts of RBP1 have arterial valve defects. Thus, this study has confirmed the utility of ST for studies of the developing heart valves and broadens our knowledge of the genes and signalling pathways important in human valve development.
The Bureaucratic Burden of Identifying your Rapist and Remaining “Cooperative”: What the Sexual Assault Kit Initiative Tells us about Sexual Assault Case Attrition and Outcomes
We analyzed a large sample of sexual assaults over almost two decades in one urban U.S. jurisdiction with previously untested sexual assault kits that were initially not successfully adjudicated (n = 717). We explored patterns of attrition through descriptive statistics and predictors of attrition through continuation-ratio modeling. Findings provide a more comprehensive framework for examining attrition, exploring the bureaucratic burden placed on victims to identify who sexually assaulted them and to remain engaged in an often harmful process and system. Implications suggest this burden could be eased via increased trauma-informed victim support and protocols and increased use of forensic evidence.
Rationale and design of the STeroids to REduce Systemic inflammation after infant heart Surgery (STRESS) trial
For decades, physicians have administered corticosteroids in the perioperative period to infants undergoing heart surgery with cardiopulmonary bypass (CPB) to reduce the postoperative systemic inflammatory response to CPB. Some question this practice because steroid efficacy has not been conclusively demonstrated and because some studies indicate that steroids could have harmful effects. STRESS is a randomized, placebo-controlled, double-blind, multicenter trial designed to evaluate safety and efficacy of perioperative steroids in infants (age < 1 year) undergoing heart surgery with CPB. Participants (planned enrollment = 1,200) are randomized 1:1 to methylprednisolone (30 mg/kg) administered into the CPB pump prime versus placebo. The trial is nested within the existing infrastructure of the Society of Thoracic Surgeons Congenital Heart Surgery Database. The primary outcome is a global rank score of mortality, major morbidities, and hospital length of stay with components ranked commensurate with their clinical severity. Secondary outcomes include several measures of major postoperative morbidity, postoperative hospital length of stay, and steroid-related safety outcomes including prevalence of hyperglycemia and postoperative infectious complications. STRESS will be one of the largest trials ever conducted in children with heart disease and will answer a decades-old question related to safety and efficacy of perioperative steroids in infants undergoing heart surgery with CPB. The pragmatic “trial within a registry” design may provide a mechanism for conducting low-cost, high-efficiency trials in a heretofore-understudied patient population.
Risk Factors for Neutropenia in Clozapine-Treated Children and Adolescents with Childhood-Onset Schizophrenia
Objective: The purpose of this study was to retrospectively analyze rates of neutropenia and risk factors for neutropenia in hospitalized children and adolescents treated with clozapine. Methods: A retrospective chart review was conducted for all patients who received clozapine at any time during a hospitalization at the National Institute of Mental Health (NIMH) between 1990 and 2011. All patients satisfied screening criteria for the NIMH childhood-onset schizophrenia study, including onset of psychosis before the age of 13 years. Absolute neutrophil count (ANC) values recorded during inpatient hospitalization were extracted for 87 eligible patients with a mean age of 13.35±2.46 years at hospitalization and a mean length of stay of 117±43 days. Results: Mild neutropenia only (lowest ANC<2000/mm3 but>1500/mm3) was observed in 27 (31%) patients and moderate neutropenia (any ANC<1500/mm3) was observed in 17 (20%) patients. There were no cases of agranulocytosis or severe infection. Significant risk factors for mild neutropenia compared with no hematologic adverse effects (HAEs) were male gender (p=0.012) and younger age (p<0.001). Male gender was also a significant risk factor for moderate neutropenia compared with no HAEs (p=0.003). If a child of African American ethnicity developed neutropenia during hospitalization at all that child was significantly more likely to develop moderate neutropenia than mild neutropenia only (p=0.017). African American boys had the highest rate of moderate neutropenia at 47%. Sixteen of the 17 patients exhibiting moderate neutropenia were successfully treated with clozapine by the time of discharge; 8 of these 16 required adjunctive lithium carbonate administration to maintain ANC>2000/mm3. Conclusions: Our study shows that the rates of neutropenia in clozapine-treated children and adolescents are considerably higher than in the adult population. Younger age, African American ethnicity, and male gender were significant risk factors. These are also risk factors for benign neutropenia in healthy children and adolescents. Despite these high rates of neutropenia, all but one of the patients with neutropenia during hospitalization were successfully discharged on clozapine.
Comparative lipidomics platform reveals distinct lipid profiles in extracellular vesicles
Background: Recently, extracellular vesicles (EVs) have been shown to play important roles in various physiological and pathological processes. One area that has attracted much attention is oncology, with different studies pointing towards the potential of utilizing EVs for diagnostics and therapy. To date, there are many reports on the protein and nucleic acid composition of EVs and their respective roles in the biological functions of these particles. Less is known about EV lipid composition and how it may contribute to various biological roles of EVs or be useful for diagnostics. We developed a high throughput acoustic mist ionisation mass spectrometry (ACMS) platform to investigate the lipid composition of EVs secreted by a panel of non-tumoural, tumoural and metastatic cell lines. Methods: A range of EV subpopulations with differences in size and protein markers were isolated from conditioned media of cell lines by differential centrifugation and filtration. EVs were characterized by nanoparticle tracking analysis, transmission electron microscopy and western blot. Finally, EV preparations were directly subjected to ACMS for analysis of lipid composition. Principle-component analysis was used to analyse and visualize spectral differences. Results: Using 1 pL per EV sample hundreds of features were detected in both positive and negative ion modes in the mass range of 400-1000 Da. Most features belonged to glycerophosphocholines, phosphorylethanolamines, phosphatidylinositols, phosphatidylserines and sphingomyelins among other lipid classes. EV subpopulations and cells were found to differ in lipid composition with some lipid classes such as phosphorylethanolamines overrepresented in EVs as compared to cells. Other differences in lipid composition, such as side chain length and degree of saturation, were observed especially when comparing metastatic to non-metastatic tumoural as well as nontumoural cell lines. Summary/Conclusion: Cells and distinct EVs subpopulations differ in their lipid composition. Additionally, comparisons of EVs released by non-tumoural, tumoural or metastatic cell lines reveal important differences in their lipid composition which could potentially be useful for diagnostics and to better understand the biological effects of lipids transferred by EVs.
Spatial transcriptomics reveals novel genes during the remodelling of the embryonic human arterial valves
Abnormalities of the arterial valves, including bicuspid aortic valve (BAV) are amongst the most common congenital defects and are a significant cause of morbidity as well as predisposition to disease in later life. Despite this, and compounded by their small size and relative inaccessibility, there is still much to understand about how the arterial valves form and remodel during embryogenesis, both at the morphological and genetic level. Here we set out to address this in human embryos, using Spatial Transcriptomics (ST). We show that ST can be used to investigate the transcriptome of the developing arterial valves, circumventing the problems of accurately dissecting out these tiny structures from the developing embryo. We show that the transcriptome of CS16 and CS19 arterial valves overlap considerably, despite being several days apart in terms of human gestation, and that expression data confirm that the great majority of the most differentially expressed genes are valve-specific. Moreover, we show that the transcriptome of the human arterial valves overlaps with that of mouse atrioventricular valves from a range of gestations, validating our dataset but also highlighting novel genes, including four that are not found in the mouse genome and have not previously been linked to valve development. Importantly, our data suggests that valve transcriptomes are under-represented when using commonly used databases to filter for genes important in cardiac development; this means that causative variants in valve-related genes may be excluded during filtering for genomic data analyses for, for example, BAV. Finally, we highlight “novel” pathways that likely play important roles in arterial valve development, showing that mouse knockouts of RBP1 have arterial valve defects. Thus, this study has confirmed the utility of ST for studies of the developing heart valves and broadens our knowledge of the genes and signalling pathways important in human valve development. Congenital heart defects, particularly those affecting the valves and septa of the heart, are very common. Despite this, few gene variants have been confirmed as disease-causing in human congenital heart (including valve) disease patients. Here we utilise spatial transcriptomics technology, which allows the identification of genes expressed in tissue slices, on embryonic human heart valves and identify a gene dataset that is human arterial valve-specific. We confirm the localisation of key novel genes to the arterial valves and highlight the relevance of the dataset by showing that mice mutant for RBP1, a novel gene identified as being highly differentially expressed in our valve dataset, have previously unidentified arterial valve defects. Using commonly used bioinformatic databases we show that filtering patient genomic data using these terms would likely exclude valve genes and thus may not identify the causative genes. Thus, we confirm that spatial transcriptomics technology can be used to study gene expression in tiny structures such as the developing heart valves and provide a new human embryonic valve dataset that can be used in future genomic studies of patients with congenital valve defects.