The University of Maryland Graduate School Baltimore (UMGSB) offers 27 master's and doctoral programs in health, physical, biomedical, medical, and social sciences.

Collections in this community

Recent Submissions

  • Prospective Clinical Investigation of Orthodontic Relapse from Gingival Clefts

    Scott, Christopher Jason; Stappert, Dina (2018)
    Background: Orthodontic space closure following premolar extraction may result in gingival cleft formation. This may contribute to orthodontic relapse due to reopening of extraction spaces. Aim: 1) To evaluate the effects gingival clefts have on relapse and opening of closed extraction spaces after orthodontic treatment. 2) To record any changes in cleft severity. 3) To establish any relationship between gingival phenotype and cleft severity. Methods: Subjects recruited from previous study in which the occurrence and severity of gingival clefts were measured during space closure. The clinical measures included the occurrence and severity of clefts and their relationship to gingival phenotype. Results: Sites with a cleft (N=42) had 42.86% relapse and those without (N=19) had 36.84% relapse. Conclusions: As cleft severity increases; the amount of relapse distance is likely to increase. Adult patients are at greater risk for relapse at extraction sites compared to adolescent patients.
  • Psychosocial Care Needs of Children with Cancer and Their Families: Perceptions and Experiences of Omani Oncologists and Nurses

    Al Balushi, Amal Juma; Johantgen, Mary E.; Mooney-Doyle, Kim (2019)
    Background: Much evidence demonstrates the psychosocial impact of childhood cancer on children and their families. While many health care systems are evolving to integrate psychosocial services into clinical care, barriers exist that must be understood before changes can be implemented in systems new to this care. Oncologists and nurses are on the front lines of care and have unique perspectives about the needs of their patients and families. Objectives: The purposes of this study were: 1) describe the experiences and perceptions of pediatric oncology physicians and nurses in Oman regarding the psychosocial care needs of children with cancer and their families; and 2) describe the barriers and facilitators to providing psychosocial care. Methods: A qualitative, phenomenological study was conducted. Purposive sampling strategy was used to recruit 26 oncologists and nurses with experience caring for children with cancer and their families. Individual, semi-structured interviews were conducted and recorded. Colaizzi's method of data analysis was utilized to inductively determine themes, clusters, and categories. Data saturation was achieved, and methodical rigor was established. Result: Four themes emerged from the data. The first was “perceived need for care beyond medicine.” The oncologists and nurses recognized that more psychosocial assessment, care, and services were needed. The second theme was “recognition of pediatric oncology as a challenging clinical practice area,” which had two subthemes: emotional burden and challenging situations. Participants described the challenges they faced trying to meet the needs of children and extended families. The third theme was “barriers to providing effective psychosocial care,” which had three subthemes: barriers related to the health care system, barriers related to health care providers, and barriers related to infrastructure and environment. The fourth theme was “providing optimal supportive care within the available facilities,” which had two subthemes: supportive care and facilitating factors. Cultural and community factors were highlighted. Conclusion: As the pediatric oncology services in Oman mature, clinicians are eager to develop the psychosocial assessments and needed services. Future research is needed to elicit the perspectives of Omani children with cancer and their families. Resources will be needed from higher authorities to design, implement, and evaluate the recommended changes.
  • Risk of Subsequent Cardiovascular Events Among Medicare Beneficiaries Diagnosed with Obstructive Sleep Apnea and Treated with Continuous Positive Airway Pressure

    Ismail, M. Doyinsola; Wickwire, Emerson M.; Scharf, Steven M., 1946-; Srivastava, Mukta C.; Somers, Vivend K.; Albrecht, Jennifer S. (2020)
    Introduction: Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular disease (CVD) but it remains uncertain whether treatment with Continuous Airway Pressure (CPAP) can prevent major cardiovascular (CV) events, especially among older adults. Research Objective: To estimate the incidence of CV events among older Medicare beneficiaries, with and without pre-existing CVD, who initiated CPAP therapy following OSA diagnosis.
  • Caregiver Distress and Burden and Patient Distress Across the Outpatient Peri-Allogenic Bone Marrow Transplantation Period

    Caves, Meredid Soto; Storr, Carla L. (2019)
    Background: Outpatient allogenic bone marrow transplants (alloBMT) are feasible due to improved vigilance and decreased transplant-related toxicities. The outpatient setting compels caregivers to fulfill non-physician roles. Few studies have examined the relationship between caregiver distress and burden and how they are manifested in the context of outpatient alloBMT; there is also scarce information on how distress manifests itself within the patient/caregiver dyad when faced with a life-threatening treatment. Purpose: Aim 1 examined the trajectory and association of caregiver distress and burden, and the movement of caregivers between caregiving states longitudinally. Aim 2 examined the distress trajectory of patients and caregivers, and assessed how they moved between low/high distressed states both individually and as a dyad. Aim 3 explored the possible association between absolute neutrophil count (ANC) and patient distress. Methods: This observational longitudinal repeated-measures study recruited patients and caregivers undergoing outpatient alloBMT. Surveys were administered at 3 time-points: infusion of donated bone marrow (T0), ANC recovery (T1), and discharge (T2). Caregivers were asked to respond to distress and burden questions using the Distress Thermometer (DT) and Caregiver Burden Scale, which measured objective and subjective demand, and subjective stress burden. Patients completed the DT surveys. ANC values for patients were extracted through medical chart review at the same time surveys were completed. Results: Caregiver distress and subjective stress burden were associated at all time points. Increase in burden leads to increase in distress. For patients and caregivers, distress was the highest at baseline and improved over time. As a dyad, the transition between high/low distressed states was ever-changing, demonstrating the dynamic nature of the alloBMT process. No significant differences were found in the distress scores of patients and caregivers, but there was a difference in distress scores along the alloBMT period, suggesting a temporal effect. ANC and patient symptomology were not consistently associated with patient distress. Conclusion: Caregiver distress and burden are related throughout the duration of the alloBMT period. As the dyad moves through the alloBMT period, they display the mutuality of distress, influencing each other as they face this difficult but life-saving journey together.
  • Humor & Opioid Recovery

    Canha, Benjamin; Scrandis, Debra (2019)
    Abstract Background: The prevalence and mortality rates of opioid use disorders (OUD) have drastically increased in recent years in the United States. Narcotics Anonymous (N.A.) is a successful behavioral program supporting recovery for individuals with OUD. Humor may play an important role in maintaining group involvement and continuing support within the culture of the N.A. program. Purpose: The purpose of this study was to understand the ideas, beliefs, attitudes and behaviors of humor in individuals recovering from OUD who are participating in the N.A. program. Design: Qualitative ethnography design was used with three types of complementary data collection methods: observations at meetings and social gatherings, personal interviews, and a focus group session. Results: Instances of humor between N.A. members were noted in observations. Recorded one-on-one interviews with ten members recovering from OUD provided details of various experiences of humor and led to development of five essential themes: Feels Good, Social, Lighten Up, Healing and Alienate. These findings highlight the mostly positive personal and social benefits participants experienced, as well as possible negative effects. A focus group of seven N.A. members provided interactive discussion of humor and discussed the need to become more conscientious of the detrimental effects of humor. Conclusion: The implications of this study suggest the need to explore various humor interventions to assess their relative effectiveness in enhancing recovering, and reducing relapses. Due to the small number of participants, results may not be generalizable to all those with OUD in N.A. or represent the possibly wide range of N.A. meetings. This study added to the depth of knowledge about the effects of humor on this population and their recovery process. The importance of humor and having fun in the recovery of OUD should be more widely recognized by nurses as they help those with OUD, as humor definitely has a role to play in supporting N.A. members’ recovery from OUD.
  • Development of the Drude Polarizable Force Field for Small Molecules Drude General Force Field (DGenff)

    Chatterjee, Payal; MacKerell, Alexander D., Jr. (2020)
    The classical Drude oscillator polarizable force field offers an explicit treatment of induced electronic polarization presently not addressed in the commonly used additive force fields. Such an empirical approach leads to an improved and more accurate representation of electrostatic interactions in Molecular Mechanics and Molecular Dynamics (MD) simulations. The Drude Polarizable Force Field presently include topologies and parameters for biomolecules such as proteins, lipids, carbohydrates, and nucleic acids along with a limited set of small molecules. The present research is an effort to expand the existing Drude-oscillator based polarizable force field of CHARMM for general small drug like molecules – Drude General Force Field (DGenFF). A thorough development of such a force field will allow users to use polarizable force fields for drug design and other chemical fields.
  • Designing Specific Inhibitors to Target S100B in Melanoma

    Vera-Rodriguez, Darex J.; Young, Brianna; Spriggs, Shardell; Yu, Wenbo; Wilder, Paul T.; MacKerell, Alexander D., Jr.; Weber, David J., Ph.D. (2020)
    Malignant melanoma (MM) is defined as the most dangerous form of skin cancer, causing a large majority of skin cancer deaths. Previous studies demonstrate S100B as a tumor marker in MM, a protein that interacts with the tumor suppressor p53, inhibiting p53 function. With the goal of blocking this interaction, three binding sites on S100B for small molecules have been identified. However, developing drugs specific for S100B over other S100-family members remains a challenge. This project aims to identify S100B-specific small molecule inhibitors and understand the basis of their specificity over other S100 family members, specifically S100A1. A 2D-[1H,15N] NMR HSQC of S100B bound to a non-specific fragment showed multiple chemical shifts perturbations (CSPs) including residues A9, L10, F43, L40, F73, and C84. Interestingly, fewer and less pronounced CSPs were observed for a S100B-specific fragment. Site-Identified Ligand Competitive Saturation (SILCS) molecular dynamics (MD) simulations were performed to determine potential S100B binding sites that could explain the CSPs. Results show a strong hydrophobic pocket at low Grid Free Energy (GFE) levels comprised by the residues that showed CSPs for compounds that bind S100B. FDA-approved compounds were tested using SILCS-Monte Carlo (MC) to determine ligand binding poses at this pocket. Specific compounds were targeted with strong hydrophobic interactions and hydrogen bonds at low Ligand GFE (GFE). These data provide important information relevant to developing S100B-specific drugs to treat MM.
  • Graduate Research Conference 2020

    University of Maryland, Baltimore. Graduate Student Association (2020-03-06)
  • Graduate Research Conference 2019

    University of Maryland, Baltimore. Graduate Student Association (2019-03-15)
  • Modulation of Pathophysiological Processes of Autoimmune Arthritis by Indole-3-Acetic acid and Indole-3-Aldehyde

    Langan, David; Meka, Rakeshchandra R.; Moudgil, Kamal (2020-03)
    Rheumatoid arthritis (RA) afflicts 0.5-1% of US adults, making it one of most common autoimmune diseases. Clinical RA is characterized by swelling of the joints of both extremities. Environmental factors, including diet and microbiome dysbiosis, are disease-modifying factors for RA. Indole-3-acetic acid (I3AA) and indole-3-aldehyde (IAld) are derived from both the diet and gut microbiota. We hypothesized that I3AA and IAld, ligands for the aryl hydrocarbon receptor (AhR), regulate critical AhR-dependent arthritisrelated processes, namely production of pro-inflammatory cytokines, angiogenesis (new blood vessel formation), and osteoclastogenesis (bone resorption). We tested this using in vitro models of these 3 processes. Both I3AA and IAld inhibited IL-1β and IL-6 expression (by RT-qPCR), in RAW264.7 (RAW) cells treated with M. tuberculosis H37Ra sonicate (H37Ra) or LPS compared with vehicle control. Additionally, I3AA-treated RAW cells cultured in the presence of receptor activated nuclear-factor kappa beta (RANKL) formed fewer osteoclasts along with reduced expression of tartrate-acid phosphatase (TRAP) and cathepsin-K expression (CatK) (by RTqPCR), compared to vehicle-treated cells; whereas, IAld-treated cells formed more osteoclast along with more TRAP and CatK expression. Human umbilical vein endothelial cell (HUVEC) tube formation (Matrigel assay), indicative of angiogenesis, was inhibited by I3AA, while IAld had minimal or no effect. These preliminary results suggest that I3AA and IAld are capable of modulating key RA-disease processes. We plan to examine the effect of AhR inhibitors on these processes, and to assess whether I3AA and/or IAld can confer protection against arthritis in a rat model of RA.
  • Observational Study Evaluating Pain in Endodontic Patients Diagnosed with Depression – A Pilot Study

    Mannan, Saurabh; Greenspan, Joel D. (2019)
    TITLE: Observational Study Evaluating Pain in Endodontic Patients Diagnosed with Depression – A Pilot Study Saurabh Mannan, Master of Science 2019 Thesis Directed By: Joel Greenspan, PhD AIM: To evaluate the role of depression in endodontic post-procedural pain METHODOLOGY: This prospective observational study enrolled 42 patients that explored the correlation between patient’s level of depression and pain perception following non-surgical root canal treatment (NSRCT). The Hospital Anxiety and Depression Scale (HADS) assessed the patient’s level of anxiety/depression pre-and postoperatively. The patient used a visual analog scale (VAS) to record their pain intensity and feelings of unpleasantness with their dental experience immediately following their NSRCT. Pain diaries recorded pain intensity post-operatively at the 2nd, 4th, and 7th day. A cohort of endodontic patients who were not diagnosed with depression served as controls. RESULT: A total of 41 patients were included, 30 non-depressed patients and 11 patients diagnosed with depression by their physicians. Two patients did not return the pain dairy. Therefore, data from 29 non-depressed patients and ten depressed patients were available for analysis. This study showed that the diagnosis of depression was significantly associated with both higher immediate post-operative pain and immediate sensations of unpleasantness. Furthermore, HADS ≥ 8 was found to be a significant predictor of greater post-operative pain at day two. CONCLUSIONS: Within the limitations of this study, either a diagnosis of depression or signs of anxiety or depression are a positive predictor of greater post-operative pain.
  • The Diagnostic Utility of Cancer Stem Cell Marker CD44 in Early Detection of Oral Cancer

    Alsalem, Bader; Meiller, Timothy F. (2019)
    The incidence of Oral Squamous Cell Carcinoma (OSCC) is expected to increase in the coming decades. In recent years, cancer biomarkers have emerged as a promising diagnostic and prognostic tool for various cancers. The cluster differentiation antigen (CD44) is among the most frequently identified cancer stem cell markers in solid tumors. Using immunohistochemistry labeling in previously diagnosed specimens, we aimed to analyze the utility of CD44 in early diagnosis of OSCC. Biopsy specimen subgroups of lateroventral tongue revealed an increased proportion of cells staining positive for CD44 in the epithelial samples of OSCC compared with erosive lichen planus and oral dysplastic lesions. CD44, in combination with other oral biomarkers, therefore, has the potential to assist in the early diagnosis of OSCC. Future studies with larger sample sizes and multiple biomarkers should be carried out, utilizing a pre-determined IHC staining and interpretation strategy to promote reproducibility of evidence.
  • Itraconazole-HPMCAS amorphous spray dried dispersions: composition and process factors impacting performance

    Honick, Moshe Avraham; Polli, James E. (2019)
    Despite their potential for improving the oral bioavailability of poorly water soluble drugs, spray dried dispersions (SDDs) have properties that make them challenging to formulate. The objective of this dissertation was to elucidate composition and process factors for favorable SDD performance and to develop fast-, medium-, and slow-release formulations for an IVIVC study. Itraconazole (ITZ) was used as a model poorly soluble drug and hypromellose acetate succinate (HPMCAS) was used as a carrier polymer for the SDDs. Film casting proved to be a useful screening method for demonstrating the feasibility of producing amorphous SDDs of ITZ and HPMCAS as well as for rank ordering the grades of HPMCAS (i.e. HPMCAS-L > HPMCAS-M > HPMCAS-H) in terms of in-vitro dissolution performance. Producing solid oral dosage forms of ITZ-HPMCAS SDDs proved challenging due to the low particle size, poor flowability, and low bulk density of the SDDs. Initial tableting on a Natoli hand-operated press showed that drug release from tablets containing SDDs of ITZ and HPMCAS-L were very sensitive to small differences in compaction pressure and porosity. Interestingly, the same sensitivity was not observed in SDDs of ITZ and HPMCAS-M. Using a compaction simulator, reproducible fast-, medium- and slow-release tablet formulations of ITZ and HPMCAS SDDs was developed by varying polymer grade (HPMCAS-L, HPMCAS-M), slugging pressure (20, 40 MPa), and compaction pressure (70, 85, 100 MPa). The performance of SDDs was further evaluated by comparing the compaction behavior of ITZ-HPMCAS SDDs and physical mixtures of ITZ and HPMCAS. Although the compressibility of both the SDDs and physical mixtures were similar, the SDDs had a greater tendency to laminate, especially at higher compression speeds. Tablets of SDDs containing ITZ and HPMCAS-L were particularly prone to lamination compared to the SDDs containing HPMCAS-M or HPMCAS-H. Interestingly, when the SDDs were not laminated they had a greater tensile strength than tablets produced with the physical mixtures. In conclusion, there are significant challenges associated with formulating SDDs of ITZ and HPMCAS. In addition to elucidating composition and process factors impacting performance, fast-, medium-, and slow-release formulations for an IVIVC study were developed.
  • Organophosphorus Insecticides as Developmental Neurotoxicants: Potential Mechanisms Contributing to Disruption of Synaptic Transmission and Cognition

    Lumsden, Eric; Albuquerque, E. X.; Pereira, Edna F. R.; 0000-0002-3900-5891 (2019)
    Acute toxicity of the organophosphorus insecticides (OPs) chlorpyrifos (CPF) and malathion (MLT) results from irreversible inhibition of acetylcholinesterase (AChE). However, prenatal exposures to CPF and MLT levels that do not cause substantial AChE inhibition have been associated with neurodevelopmental disorders in children, particularly boys. Preclinical studies have shown that developmental exposures of rodents to low levels of CPF also result in sexually dimorphic learning and memory impairments. The finding that cognitive deficits observed in male guinea pigs prenatally exposed to subacute doses of CPF correlate with an increase of GABAergic transmission in hippocampal CA1 pyramidal neurons. The first part of this study was designed to model in vitro this CPF-induced increase in GABAergic transmission. To this end, rat primary hippocampal cultures were exposed for 5-6 days to CPF (3-300 nM) or vehicle starting at different times after plating. Subsequently, excitatory and inhibitory postsynaptic currents (EPSCs and IPSCs) were recorded from voltage-clamped neurons approximately one week after the end of the exposures. The IPSC frequency was significantly higher in neurons of cultures exposed to 30 nM CPF than in neurons of vehicle-exposed cultures. This in vitro model becomes unique for studies aimed at identifying mechanisms that underlie the developmental neurotoxicity of CPF. Previous studies reported that i) CPF interacts with the cannabinoid receptor type 1 (CB1R) both directly and indirectly, and ii) CB1R plays a regulatory role in synaptogenesis. To determine whether CB1Rs contribute to CPF-induced increase in GABAergic transmission, primary hippocampal cultures were exposed to CPF or vehicle with or without the CB1R antagonist AM4113 for 5-6 days.. Results presented here reveal that AM4113 mimicked the effect of CPF on GABAergic transmission and that there is no synergistic or additive effect between CPF and AM4113. These results suggest that CPF affects synaptogenesis by directly or indirectly decreasing the tonic activity of CB1Rs. The second part of this study was designed to demonstrate the developmental neurotoxicity of MLT in an animal model. Pregnant guinea pigs were exposed to a MLT dose regimen that induced no significant brain or blood AChE inhibition (20 mg/kg/day, ~gestation days 53 to 62). When tested in the Morris water maze, prepubertal male and female guinea pigs that had been prenatally exposed to MLT presented learning and memory deficits. To our knowledge this is the first demonstration of a cause-effect relationship between prenatal MLT exposures and postnatal cognitive deficits. The finding that spatial learning and memory deficits following prenatal MLT exposure resemble those following prenatal CPF exposure suggest that a common off-target mechanism may underlie the developmental neurotoxicity of both OPs.
  • Biases and caveats to implementing genomic medicine in diverse populations

    Kessler, Michael D.; O'Connor, Timothy D.; 0000-0003-1258-5221 (2019)
    Genetic science has traditionally focused on the study of European populations, which has resulted in the under-representation of other ancestral backgrounds across the vast majority of genetic resources. Since data derived from a limited number of ancestral backgrounds are unlikely to represent the biological variation inherent to diverse populations, genetic and genomic methods and models predicated on this Eurocentric data will have questionable accuracy and limited value when applied to diverse patient populations. This can drive scientific and/or clinical disparities, which can then seem opaque and be difficult to resolve. The work outlined in this thesis aims to increase the prevalence of ancestrally informed genetic science by characterizing bias deriving from a lack of ancestry awareness, evaluating ancestral representation in genomic resources, and identifying novel ancestry-informed biological signal. I first characterize bias by evaluating a typical clinical variant prioritization pipeline, and I demonstrate a significant positive correlation between African ancestry proportion and the identified number of clinically evaluable variants. I then more directly explore ancestral representation across translational resources by estimating the genetic ancestry for 1,018 common cancer cell lines. This analysis highlights the marked ancestral underrepresentation that exists among preclinical cancer cell line models, and identifies novel signals of ancestry-specific gene expression and somatic mutation. Finally, I evaluate how de novo mutation rates vary across diverse human populations from the NHLBI Trans-Omics for Precision Medicine (TOPMed) program. I find associations with heterozygosity, a reduced mutation rate in the Amish founder population, and near zero estimates of narrow-sense heritability. On the whole, these findings help to quantify the effects of ancestral diversity and under-representation on the application of genomic medicine.
  • The Design and Development of Dual MCL-1/BCL-2 and HDM2/Bcl-2 Protein Family Inhibitors Using a Polypharmacology Approach

    Drennen, Brandon; Fletcher, Steven (2019)
    Apoptosis, a cellular process that leads to cell death, is a vital signaling pathway for maintaining homeostasis. Intracellular-activated apoptosis is regulated by the B-cell lymphoma 2 (BCL-2) family of proteins, which encompasses two classes of proteins: the pro-apoptotic and anti-apoptotic members. Apoptosis is controlled by a protein-protein interaction (PPI) between the two members. Specifically, the anti-apoptotic proteins’ surface hydrophobic binding groove binds to the α-helical Bcl-2 homology 3 (BH3) domain of the pro-apoptotic proteins, thus inhibiting apoptosis. During apoptotic conditions, BH3 activator proteins are expressed and disrupt the PPI, initiating apoptosis. During tumorigenesis, the anti-apoptotic proteins are overexpressed and capture the activator proteins before they can act, progressing tumor development. A strategy developed to overcome this oncogenic transformation is BH3 mimicry, the design of small molecules that behave like BH3 activators to free the pro-apoptotic proteins. Though potent BH3 mimetics have been synthesized, cytotoxic and resistance issues have arisen. Specifically, BCL-XL inhibition causes thrombocytopenia within patients and BCL-2 inhibition causes resistance mechanisms to emerge that involve the upregulation of MCL-1. Presently, there are no potent dual inhibitors of BCL-2 and MCL-1 to overcome these issues. Additionally, p53 has been shown to regulate apoptosis through the Bcl-2 family by either direct interactions or increasing their expression. P53 is rapidly degraded due to the overexpression of HDM2, a ubiquitin ligase, within cancer cells. The PPI between p53 and HDM2 resembles the PPI between the members of the Bcl-2 family. Also, Venetoclax (BCL-2 inhibitor) and idasanutlin (HDM2 inhibitor) act synergistically in combination therapies. Thus, we followed a polypharmacology approach to synthesize dual BCL-2/MCL-1 and dual HDM2/Bcl-2 family inhibitors. We were able to create potent dual MCL-1/BCL-2 indazole inhibitors (Ki MCL-1 < 1.50 µM, BCL-2 < 0.050 µM, BCL-XL > 10.00 µM), dual HDM2/Bcl-2 family pyrazole and imidazole inhibitors (Ki MCL-1 < 0.050 µM, HDM2 < 25.00 µM), HSQC-confirmed nicotinate-based MCL-1 inhibitors (Ki MCL-1 < 3.00 µM) and a new alpha-helix mimetic scaffold for disrupting PPIs. Further optimization of these inhibitors is planned, along with cell viability studies. Overall, these inhibitors can serve as starting points for future experiments and polypharmacology designs.
  • Bioinformatic Analysis of Single Nucleus Transcriptome Data of Huntington's Disease

    Malaiya, Sonia; Ament, Seth A.; 0000-0002-0010-3259 (2019)
    Huntington’s Disease (HD) is a dominantly inherited neurodegenerative disorder caused by a trinucleotide expansion in exon 1 of the Huntingtin (Htt) gene. The earliest changes in HD are observed in the striatum, prior to the onset of symptoms. Here we use a knock in HttQ175/+ mouse model to perform single nucleus RNA sequencing (snRNAseq) of the striatums of four HttQ175/+ and three wild type 14 and 15 month old mice and obtain their expression profiles. Using available snRNAseq quality control and analysis methods, we identify eleven cell types within our samples, including the newly discovered “Eccentric MSNs”. We compute the differentially expressed genes between the two genotypes and find significant lowering of cell type specific markers in most cells with the HttQ175/+ mutation. Trajectory analyses reveal stages of HttQ175/+ MSNs that range from identical to extremely distinguished form the wild type MSNs, supporting the length dependent somatic expansion hypothesis.
  • Sex differences in soman-induced toxicity and response to medical countermeasures in serum carboxylesterase knockout mice.

    Kundrick, Erica; Pereira, Edna; Lumley, Lucille A.; 0000-0002-4222-1528 (2019)
    In rodents, exposure to chemical warfare nerve agent soman leads to status epilepticus and extensive neuronal loss. Mice and rats are less sensitive to nerve agent toxicity compared to primates since high levels of plasma carboxylesterase, which acts as a bioscavenger against soman, increase resistance of these rodents to organophosphorus poisoning. One objective of this research project was to determine the LD50s of soman in female plasma carboxylesterase knockout (ES1-/-) mice at the different stages of their estrous cycle and to compare toxicity across estrous and with male mice. Female mice in estrus were less susceptible to the soman lethality compared to female mice in proestrus and to male mice. The second objective was to evaluate dose-response effects of delayed midazolam treatment in soman-exposed ES1-/- mice. Delayed midazolam dose-dependently increased survival and reduced seizure severity but did not prevent epileptogenesis or brain pathology in seizure-sensitive brain regions, independent of sex.
  • The Roles of Autophagic SNARE proteins SNAP29 and SNAP47 in Autophagy and Enterovirus D68 Replication

    Corona, Abigail; Jackson, William T.; 0000-0003-2271-4541 (2019)
    Enterovirus-D68 (EV-D68) is a positive-sense, single-stranded RNA virus of the Picornaviridae family that causes respiratory disease in children and has been implicated in recent outbreaks of acute flaccid myelitis, a severe paralysis syndrome. We have demonstrated that EV-D68 induces autophagy upon infection and modifies the autophagic process to benefit its own replication. Autophagy is a regulated process of cytosolic degradation in eukaryotic cells which maintains cellular homeostasis by degrading damaged organelles, protein aggregates, microbes and other xenobiotics in the cytoplasm. The autophagic process is characterized by the formation of double-membraned autophagosomes around cytosolic cargo, which then undergo a series of fusion steps with endosomes and lysosomes to degrade the vesicle’s contents. The autophagy pathway is targeted by many pathogens, either to protect themselves from degradation or to utilize components to benefit replication. EV-D68 uses virally-encoded proteases to cleave an autophagosome fusion SNARE protein, SNAP29, blocking delivery of autophagosome contents, including nascent viruses, to the lysosome. Our data show that relocalization occurs for SNAP47 during autophagy induction, and is required for normal virus replication. SNAP47 plays a major role in acidification of autophagosomes into amphisomes, with binding partner VAMP7, which we hypothesize promotes maturation of virions into infectious particles. Using both viral- and non-viral forms of autophagy induction, these data suggest that the cellular network of SNARE proteins is being redirected during infection to promote EV-D68 replication and egress from the cell.
  • Designing Next Generation Genomics and Serological Tools for Surveillance of Plasmodium vivax Malaria to Guide Elimination Efforts in Southeast Asia

    Agrawal, Sonia; Plowe, Christopher V.; 0000-0003-4484-7433 (2019)
    Malaria is a major global health problem caused by mosquito-borne, protozoan parasites belonging to the genus Plasmodium. Plasmodium vivax, the human malaria parasite with the widest global distribution, accounts for majority of the total malaria cases outside sub-Saharan Africa. The inability to establish long term in vitro culture system and low parasite densities, combined with high levels of human genomic DNA isolated from patient samples with P. vivax infections, makes it difficult to obtain sufficient amounts of parasite DNA for whole genome sequencing (WGS). New, reliable, highly sensitive and specific methods are needed to produce high quality P. vivax WGS data. Genome-wide analyses of the parasite, using WGS, have the potential to improve our understanding of parasite population dynamics and help identifying locations that serve as possible transmission sources and sinks. Additionally, protein microarrays that can simultaneously measure human antibody responses to a large number of Plasmodium antigens have the potential to identify P. vivax specific biomarkers to detect not only current but also past malaria infections, providing a more sensitive surveillance tool for identifying human populations at risk. To address these needs, using Roche/NimbleGen SeqCap EZ whole genome capture technology, high quality WGS data was generated from P. vivax clinical samples collected from the China-Myanmar border. This new genome-wide data along with publicly available WGS from circulating isolates in Southeast Asia were utilized to characterize parasite genetic diversity and relatedness, population structure, complexity of infection, and distinguish locally transmitted infections from imported P. vivax infections revealing clonal parasite population on the China-Myanmar border. Using protein microarray analyses, several P. vivax specific serologic markers during active infection were identified that may serve as useful biomarkers of current or recent P. vivax infection supporting the possibility of serology as a tool for estimating species-specific malaria exposure to P. vivax in heterogeneous malaria transmission settings. The combination of next generation tools attempted to be designed as part of this dissertation will help improve the understanding of the genomic epidemiology and estimates of transmission patterns of this human malaria parasite, thus, guiding rational P. vivax malaria control and elimination policies in Southeast Asia.

View more