RSS 1.0eScholarship@UMassChan
Welcome to the new eScholarship@UMassChan! eScholarship@UMassChan is a freely available digital repository offering worldwide access to the research and scholarly work of the UMass Chan Medical School community. We welcome submissions from our faculty, researchers, staff, and students. eScholarship@UMassChan is a service of the Lamar Soutter Library, Worcester, MA, USA.
Questions? See the Help menu in the sidebar or contact escholarship@umassmed.edu.
Communities in eScholarship@UMassChan
Select a community to browse its collections.
Recently Published
-
Adulting Shorts: The “TEA” on IEPs Part 2This info-comic is for high school students to help them understand what an Individualized Educational Plan or IEP is, what transition planning is, and the importance of the student being involved in them. This is Part 2 of the story. Find Part 1 here: https://www.umassmed.edu/TransitionsACR/publication/comic/2021/09/tea-on-ieps-part-1/
-
In vitro Methods to Better Evaluate Drug Responses in CancerEvaluating anti-cancer drugs in vitro is an important aspect of the drug development pipeline. When evaluating anti-cancer drugs, two different measurements are used: relative viability, which scores an amalgam of proliferative arrest and cell death, and fractional viability, which specifically scores the degree of cell killing. These two metrics are often used interchangeably despite measuring different aspects of a drug response. This study explored the relationship between drug-induced growth inhibition and cell death, and found that most drugs affect both proliferation and death, but in different proportions, and with different relative timing. This causes a non-uniform relationship between relative and fractional response measurements. To unify these measurements, I created a data visualization and analysis platform, called drug GRADE, which characterizes the degree to which death contributes to an observed drug response. GRADE captures drug- and genotype-specific responses, which are not captured using traditional pharmaco-metrics. Current in vitro anti-cancer drug evaluation practices measure drug responses with cancer cell lines in mono-culture. However, many cell types in the tumor microenvironment influence cancer’s drug response and disease progression. Therefore, current drug evaluation practices overlook complex cell-cell interactions that influence cancer’s drug response. In this study, I developed a high-throughput assay to study the effect of another cell type (cytotoxic T cells) on cancer viability in co-culture, in vitro. Further, I developed a reference framework to model the complex interaction between cancer cells and cytotoxic T cells, and to model how T cell-mediated cell death is modulated by anti-cancer drug treatment. Taken together, this study highlights two new methods which enable better in vitro evaluation of drug responses in cancer.
-
Cellular heterogeneity and gene regulatory network coordination during thymic epithelial cell developmentThymic epithelial cells, derived from the pharyngeal endoderm, perform essential functions for establishing a self-tolerant immune system. Unsurprisingly, dysfunction of thymic epithelial cells resulting from maldevelopment of the pharyngeal endoderm causes immunodeficiency or autoimmunity syndromes, some of which cannot be fully explained according to known genetic errors. Despite the functional significance and disease-relevance of pharyngeal endoderm with respect to thymic epithelial cells, we lack a comprehensive understanding of the gene regulatory networks driving pharyngeal endoderm differentiation. To close this gap, we applied transcriptome and chromatin accessibility single cell profiling to generate a multi-omic developmental resource covering pharyngeal differentiation toward organ-specific epithelia in the mouse embryo. We identified cell-type specific gene regulation of developing organ domains and characterized the role of an immunodeficiency-associated forkhead box transcription factor, Foxn1, during early thymus development. Furthermore, analyses of the pharyngeal endoderm multi-omics atlas led us to discover a novel gene associated with thymus development, namely Grainyhead-like3 (Grhl3). We assessed the expression pattern and the functional importance of Grhl3 in the prenatal and postnatal thymus, uncovering a putative role in a specialized medullary thymic subtype. In conclusion, this dissertation provides insight on the molecular basis of pharyngeal endoderm differentiation and subsequent development of the thymus.
-
Regulated Gene Therapy Towards Glycosphingolipid Biosynthesis DeficienciesGlycosphingolipids (GSLs) are a group of amphipathic glycolipids essential for maintaining the normal ultrastructure and function of neural and oligodendrocyte cell membranes throughout the mammalian central nervous system (CNS). De novo GSL biosynthesis defects cause severe neurological diseases such as GM3 synthase deficiency (GM3SD) and hereditary sensory and autonomic neuropathy type 1A (HSAN1A), each lacking effective treatment. Here, we developed two distinct potential therapeutic approaches for these neurological diseases. For GM3SD that is caused by loss-of-function mutations in ST3GAL5, we employed a recombinant adeno-associated virus (rAAV)-mediated human ST3GAL5 gene replacement therapy. First, using ST3GAL5 mutant patient iPSC-derived neurons and St3gal5 knock-out mouse models, we have achieved ST3GAL5 gene normalization and restoration of the functional products, cerebral gangliosides. Importantly, we revealed the hepatic toxicity caused by ubiquitous expression of ST3GAL5 and optimized a CNS-restricted rAAV gene replacement therapy for the safe and efficacious rescue of the severe neurodevelopmental phenotypes and early lethality in disease mouse models, given by both intracerebroventricular and intravenous routes of administration. These results support for further clinical development of ST3GAL5 gene therapy. On the other hand, to target gain-of-function SPTLC1 mutation caused HSAN1A, we screened antisense oligonucleotides (ASOs) and achieved efficient reduction of mutant SPTLC1 transcripts and its toxic products in patient-fibroblasts. In summary, this thesis describes the potential of novel rAAV-mediated gene replacement therapy in GM3SD and allele-specific ASO silencing in HSAN1A, highlighting the significance of personalized gene therapy for monogenic neurological disorders.
-
Investigating Proteolytic Processing of Ataxin 2, a Neurodegenerative Disease Associated ProteinAtaxin 2 (ATXN2) is a ubiquitously expressed mRNA binding protein involved in the development and progression of spinocerebellar ataxia 2 (SCA2) and amyotrophic lateral sclerosis (ALS). In the context of both neurodegenerative diseases, its N-terminal polyglutamine (polyQ) domain is mutated and expanded in length. Several other polyQ proteins, such as huntingtin (Htt), ataxin 3 (ATXN3), and ataxin 7 (ATXN7), undergo proteolytic processing that produces toxic fragments containing their polyQ domains. Investigating how ATXN2 is regulated by proteolysis is hindered by the lack of available molecular biological tools such as N-terminal ATXN2 antibodies to target and analyze the endogenous N-terminus of ATXN2. To circumvent this challenge, I developed a transient overexpression model of N-terminally tagged ATXN2 in HEK293E cells. Here, I demonstrate that both wild-type and mutant ATXN2 are targets of N-terminal proteolysis. I confirmed that ATXN2 produces an independent polyQ cleavage fragment like other polyQ proteins through basic molecular biology approaches such as Western blotting and immunoprecipitation. Additionally, I identified the specific region that is both necessary and sufficient for cleavage to occur via deletion mapping with multiple truncated ATXN2 mutants and reporter constructs. Further definition of ATXN2 as a target of proteolytic cleavage aligns it with other neurodegenerative polyQ proteins, and proteolysis is currently a less explored avenue of research for ATXN2-related disease development, progression, and therapeutic modalities. This work reveals a novel site that directs cleavage of ATXN2 and provides a potential avenue of investigation for how ATXN2 posttranslational modifications contribute to the progression of SCA2 and ALS.
-
UMCCTS Newsletter, August 2022This is the August 2022 issue of the UMass Center for Clinical and Translational Science Newsletter containing news and events of interest.
-
Journal of eScience Librarianship (JeSLIB) Publishing ProcessDescribes the roles and responsibilities, author guidelines, and peer review process for the Journal of eScience Librarianship.
-
High bacillary burden and the ESX-1 type VII secretion system promote MHC class I presentation to CD8 T-cells during Mycobacterium tuberculosis infectionT-cell mediated immunity is required for optimal protection against Mycobacterium tuberculosis (Mtb) infection, but often fails to completely clear the pathogen. Mtb has evolved strategies to subvert host immunity so it can persist in host cells despite pressure from innate and adaptive immunity. While cytotoxic CD8 T-cells should recognize and clear infected host cells, eliminating Mtb’s intracellular niche, previous findings have demonstrated otherwise [1]. In fact, we have shown that CD8 T-cells specific to the immunodominant antigen TB10.4 poorly recognize Mtb infected macrophages in vitro. Here we extend our initial findings to show that class I MHC-restricted epitopes other than TB10.44-11 are inefficiently presented by Mtb-infected macrophages to CD8 T cells. The only exception we find is for heavily infected macrophages. During high burden infections, macrophages cross-present TB10.4 antigen to CD8 T-cells. These high burden infections result in considerable cell death, and we find that uninfected macrophages effectively scavenge dead cellular debris and cross-present this antigen to CD8 T cells. Furthermore, we find that cross-presentation by heavily infected cells is dependent on the ESX-1 type VII secretion system, suggesting that phagosomal membrane damage and host cell death are crucial for effective class I MHC cross-presentation during Mtb infection.
-
International Controlled Study of Revascularization and Outcomes Following COVID-Positive Mechanical ThrombectomyBACKGROUND: Previous studies suggest that the mechanisms and outcomes in COVID-19-associated stroke differ from those with non-COVID-19 strokes, but there is limited comparative evidence focusing on these populations. Therefore, we aimed to determine if a significant association exists between COVID-19 status with revascularization and functional outcomes following thrombectomy for large vessel occlusion (LVO), after adjustment for potential confounding factors. METHODS: A cross-sectional, international multicenter retrospective study of consecutively admitted COVID-19 patients with concomitant acute LVO, compared to a control group without COVID-19. Data collected included age, gender, comorbidities, clinical characteristics, details of the involved vessels, procedural technique, and various outcomes. A multivariable adjusted analysis was conducted. RESULTS: In this cohort of 697 patients with acute LVO, 302 had COVID-19 while 395 patients did not. There was a significant difference (p < 0.001) in the mean age (in years) and gender of patients, with younger patients and more males in the COVID-19 group. In terms of favorable revascularization (mTICI 3), COVID-19 was associated with lower odds of complete revascularization [OR=0.33; 95% CI=0.23-0.48; p < 0.001], which persisted on multivariable modelling with adjustment for other predictors [aOR=0.30; 95% CI=0.12-0.77; p=0.012]. Moreover, endovascular complications, in-hospital mortality, and length of hospital stay were significantly higher among COVID-19 patients (p < 0.001). CONCLUSION: COVID-19 was an independent predictor of incomplete revascularization and poor functional outcome in patients with stroke due to LVO. Furthermore, COVID-19 patients with LVO were more often younger and suffered higher morbidity/mortality rates.
-
The Role of Age-Associated B Cells (ABC) in Combating Influenza InfectionWith age, follicular helper T cell (TFH) dependent B cell responses erode, reducing B cell memory and long-term antibody responses. However, aged mice and humans develop an alternative B cell population, termed age-associated B cells (ABC), that may produce TFH independent antibodies. ABC lack CD21 and CD23 expression, and some express transcription factors and adhesion molecules indicative of antigen exposure. Some of these have been implicated in autoimmunity. We found a unique population of responding B cells following influenza A virus (IAV) infection, which was Fashi/GL7neg. We postulated that the CD21-CD23-ABC might be progenitors of these non-follicular B cells, that we called induced ABC (iABC). Using T-deficient RAG KO and TFH deficient SAP KO hosts, we found that the CD21-CD23-ABC can become iABC (FasHiGL7-) upon IAV infection. These iABC share the same phenotype of iABC found in infected aged mice and can become Ab-producing cells without T cell help. We showed that CD21-CD23-ABC can be separated into IgD+ (putative naïve B cells) vs. IgD- (memory-like B cells). We followed their ability to become iABC in SAP KO hosts. The IgD+ABC were most efficient at giving rise to iABC. Further transfer studies revealed that iABC generation from donor IgD+ABC requires extrinsic TLR signaling, and IgD+ABC can provide Ab-medicated protection. We concluded that upon T-independent stimulation, IgD+ABC (CD21-CD23-) become iABC (Fashi/GL7neg), some of which can secrete IAV-specific Ab and may provide protection against IAV.
-
UMCCTS Newsletter, July 2022This is the July 2022 issue of the UMass Center for Clinical and Translational Science Newsletter containing news and events of interest.
-
Data and Code from "Show me the data! Data sharing practices demonstrated in published research at the University of Massachusetts Chan Medical School"Data extracted from articles published by UMass Chan researchers to determine where and how data was being shared. Code from the analysis is also included.
-
COVID-19: a gray swan's impact on the adoption of novel medical technologiesThe COVID-19 pandemic offers a unique context and opportunity to investigate changes in healthcare professional perceptions towards the adoption of novel medical technologies, such as point-of-care technologies (POCTs). POCTs are a nascent technology that has experienced rapid growth as a result of COVID-19 due to their ability to increase healthcare accessibility via near-patient delivery, including at-home. We surveyed healthcare professionals before and during COVID-19 to explore whether the pandemic altered their perceptions about the usefulness of POCTs. Our network analysis method provided a structure for understanding this changing phenomenon. We uncovered that POCTs are not only useful for diagnosing COVID-19, but healthcare professionals also perceive them as increasingly important for diagnosing other diseases, such as cardiovascular, endocrine, respiratory, and metabolic diseases. Healthcare professionals also viewed POCTs as facilitating the humanization of epidemiology by improving disease management/monitoring and strengthening the clinician-patient relationship. As the accuracy and integration of these technologies into mainstream healthcare delivery improves, hurdles to their adoption dissipate, thereby encouraging healthcare professionals to rely upon them more frequently to diagnose, manage, and monitor diseases. The technological advances made in POCTs during COVID-19, combined with shifting positive perceptions of their utility by healthcare professionals, may better prepare us for the next pandemic.
-
Novel Genetic Pathways in Functional Regulation of Hematopoietic Stem CellsHematopoietic stem cells (HSCs) are a rare population of bone marrow cells that have self-renewal and differentiating capabilities enabling them to produce all blood lineages during normal hematopoiesis. Many molecular pathways are involved in the regulation of HSCs, and the survival, maintenance and proliferation of these cells must be tightly controlled to avoid aberrant activities that can cause blood diseases, such as hematopoietic malignancies. Therefore, additional factors involved in the functional regulation of HSCs must be discovered to provide new therapeutic treatments for hematopoietic diseases. In chapter I, I briefly introduce the hematopoietic system and hierarchy through which HSCs can produce all mature blood cells in the lifespan. I also describe various methods to identify different hematopoietic cells, with a focus on using cell surface antigen markers. I additionally discuss an important method to study HSCs in mice by using bone marrow transplantation in which the donor cells are manipulated to examine the role of a gene of interest. I also briefly describe several signaling pathways important in HSCs, such as the Bmp, Wnt, Hedgehog and Notch signaling pathways. I provide known relevant information to my thesis work on c-Kit and Sca-1 receptors, as well as on LSK and LSK- cells. In chapter II, I describe my findings regarding a novel mechanism in which Ikzf3 plays a suppressive role in regulating HSC survival and maintenance. Ikzf3 suppresses the population of LSK (lineage-Sca-1+c-Kit+) cells that contains HSCs, and increases the LSK- (lineage-Sca-1+c-Kit-) population, which is highly apoptotic and derived from the LSK population. The DNA binding domain of Ikzf3 is required for its inhibition of HSCs, and Ikzf3 downregulates the expression of Bcl-2, Bcl-xL and c-Myc. Ikzf3 expression in HSCs is maintained at low levels by the c-Kit pathway. In chapter III, on the basis of data from microarray analysis previously performed to compare gene expression profiles between Hif1a knockout HSCs and wild type HSCs, the effects of both Hif1a and Notch1 deletion on HSC regulation are examined. Loss of both Hif1a and Notch1 induces the development of myelodysplastic/myeloproliferative diseases, which are clonal hematopoietic stem cell neoplasms characterized by abnormal regulation of the myeloid pathways for cellular proliferation, maturation and survival. Loss of both Hif1a and Notch1 also leads to a loss of HSC function. These findings indicate a mechanism through which the hypoxia pathway acts in coordination with the Notch pathway in HSCs. In chapter IV, I summarize the findings from chapter II and III and discuss the importance of these results in the field. I also provide the future directions that can answer more questions to expand our knowledge on these pathways. Together, the findings reveal two novel pathways involved in functional regulation of HSCs: (i) the Ikzf3 pathway, which involves c-Kit, Icsbp, Bcl-2, Bcl-xL and c-Myc, and suppresses normal HSCs to maintain homeostasis and (ii) the synergy of Hif1a and Notch1 in regulating HSCs. The loss of both genes can cause myelodysplastic/myeloproliferative-like diseases.
-
Surveillance of Host and Pathogen Derived Metabolites Activates Intestinal ImmunityIntestinal epithelial cells function, in part, to detect infection with pathogenic organisms and are key regulators of intestinal immune homeostasis. However, it is not fully understood how intestinal epithelial cells sense pathogen infection and coordinate the induction of protective immune defenses. Here, we define two new mechanisms of innate immune regulation in a metazoan host. First, we characterize the first bacterial pattern recognition receptor and its natural ligand in Caenorhabditis elegans. We show that the C. elegans nuclear hormone receptor NHR-86/HNF4 directly senses phenazine-1-carboxamide (PCN), a metabolite produced by pathogenic strains of Pseudomonas aeruginosa. PCN binds to the ligand-binding domain of NHR-86/HNF4, a ligand-gated transcription factor, and activates innate immunity in intestinal epithelial cells. In addition, we show that C. elegans NHR-86 senses PCN, and not other phenazine metabolites, as a marker of pathogen virulence to engage protective anti-pathogen defenses. Second, we show that a phase transition of the C. elegans Toll/interleukin-1 receptor domain protein (TIR-1) controls signaling by the C. elegans p38 PMK-1 MAPK pathway. Physiologic stress, both P. aeruginosa infection and sterol scarcity, induce multimerization of TIR-1 within intestinal epithelial cells. Like the mammalian homolog of TIR-1, SARM1, oligomerization and phase transition of C. elegans TIR-1 dramatically potentiate its NAD+ glycohydrolase activity. TIR-1/SARM1 multimerization and NAD+ glycohydrolase activity are required for activation of C. elegans p38 PMK-1 pathway signaling and pathogen resistance. These data uncover a mechanism by which nematodes interpret environmental conditions to prime innate immune defenses and promote survival in microbe rich environments. C. elegans animals augment these immune defenses by surveying for ligands specifically associated with toxigenic pathogens that are poised to cause disease. These findings define a new paradigm of intestinal immune control that informs the evolution of innate immunity in all metazoans.
-
Gliotransmission Orchestrates Neuronal Type-specific Axon RegenerationWhy closely related neuronal types differ in their axon regenerative abilities remains elusive. Here, I demonstrate gliotransmission determines such a difference in Drosophila larval sensory neurons. Axotomy activates ensheathing glia, which signal to regenerative neurons through the gliotransmitter adenosine, to mount regenerative programs including neuronal activity and Ras. Surprisingly, ensheathing glia do not signal to non-regenerative neurons. Such neuronal type-specific responses to gliotransmission result from specific expression of adenosine receptors in regenerative neurons. Disrupting gliotransmission impedes regeneration of regenerative neurons. Strikingly, reconstitution of gliotransmission in non-regenerative neurons enables them to regenerate. Furthermore, activation of an adenosine receptor in adult mice promotes both regeneration and survival of retinal ganglion cells, uncovering a conserved pro-regenerative role of adenosine receptors. My studies demonstrate gliotransmission as a novel mechanism by which glia instruct axon regeneration, with neuronal type-specificity, and suggest targeting purinergic signaling as a new strategy for mammalian central nervous system repair.
-
Updating and Improving the Capstone Course Experience for Learners and TeachersBackground:The Capstone Scholarship and Discovery Course (“Capstone course”) is a required four-year course which aims to support students in the design, execution, writing, and presentation of a longitudinal scholarly project. Currently, the Capstone course meets criteria for “underperforming” designation (<75% approval) designationin two areas: Overall, how would you rate this course? | 2.52/4 | 52.77% Feedback on reports supported progress/learning | 2.95/4 | 74.07% The overall medical school curriculum is transitioning to a new curriculum (“Vista”) in which Capstone will fit into the context of student-selected Pathways. As the Capstone student representative responsible for communicating student feedback to Capstone leadership, I became interested in taking advantage of this opportunity to improve the course. I believe that every medical student should feel supported in their Capstone research and finish medical school with a foundational understanding of how to conduct longitudinal scholarly work. Objectives: 1) Identify student and faculty concerns about the Capstone course 2) Propose potential changes to the Capstone course to address the most significant concerns 3) Measure student approval towards these proposed changes 4) Summarize and present the most highly student-approved proposed changes to Capstone Course Leadership Team. Methods: I reviewed all Capstone oasis evaluations from the 2020 – 2021 Academic Year, which included 109 faculty evaluations of students, 133 student evaluations of Capstone faculty (~80% response rate), and 136 student evaluations of the Capstone course (~81% response rate). I also created a pre-survey to assess the most unclear aspects of the Capstone course as well as top barriers to meeting deadlines. I received 44 survey responses from third-year students (~22% response rate) and 47 responses from fourth-year students (~30% response rate). From the oasis evaluations and survey responses, I identified the most significant concerns. I generated twenty-two proposed changes to address these concerns, and created a slideshow that summarizes these proposed changes to the Capstone course. This was distributed to current third- and fourth-year medical students, along with a post-survey where students could vote on the proposed changes and indicate whether these changes addressed the unclear aspects of the Capstone course and top barriers to meeting deadlines. (Terminology note: learning community assigned affiliate = “affiliate”, faculty advisor specific to project = “advisor”). Results: I received 29 post-survey responses from third-year students (~15% response rate) and 37 responses from fourth-year students (~23% response rate). Between the pre- and post-surveys, the average % of students finding certain aspects of Capstone “unclear” decreased by 26.1%, and the average % of students rating certain barriers as significant for meeting Capstone deadlines decreased by 15.5%. Notably, the post-survey found that some students believe the proposed changes would not address their lack of interest in doing a longitudinal project (53.1%), and that certain projects students are interested in would still not meet Capstone requirements (31.3%). An abbreviated summary of the most popular proposed changes (>50% of students agree, and/or >10% of students indicated it as one of their top three changes, highlighted in bold) is below. Proposed Solution | % top 3 | % disagree | % neutral | % agree 1a) Create research project database | 30.4 | 3.1 | 12.3 | 84.6 1b) Create roster of past highly-rated advisors (based on oasis evals) | 7.1 | 4.6 | 24.6 | 70.8 1d) MS1 Capstone curriculum focused on developing research skills | 23.2 | 9.2 | 18.5 | 72.3 1e) Affiliate must give feedback on project feasibility as a Capstone project within a month of project proposal. | 5.4 | 6.2 | 32.3 | 61.5 2a) Add additional, optional Capstone poster presentation session before ERAS deadline so presentation can be on ERAS app | 10.7 | 6.2 | 24.6 | 69.2 2b) Optional workshops (or asynchronous videos) on common issues | 5.4 | 15.4 | 32.3 | 52.3 3a) In place of report submissions, create a live document that can be accessed by affiliate and mentor | 16.1 | 10.8 | 26.2 | 63.1 3b) Flexible format (such as Senior Scholars format: background, objectives, methods, results, conclusion) with no length requirement | 21.4 | 1.5 | 12.3 | 86.2 3c) Rework deadlines to avoid exam dates, Step 1 period, holidays, and flexible range of deadlines provided during clinical rotations | 33.9 | 0 | 3.1 | 96.9 3d) Timeline of deadlines given to affiliates and mentors, with exam dates and Step 1 period marked on timeline | 5.4 | 1.6 | 15.6 | 82.8 3e) No punishment for those who get their work done early | 23.2 | 0 | 4.7 | 95.3 3f) Meeting with affiliate can substitute for an update with affiliate approval | 1.8 | 4.7 | 25 | 70.3 4a) Projects that take place over >1 month should be accepted as “longitudinal” and all affiliates should be on the same page. | 42.9 | 1.5 | 16.9 | 81.5 5a) Students may submit outside project to their affiliate to be approved for Capstone credit as long as they worked on this project during med school | 44.6 | 1.5 | 10.8 | 87.7 5c) Website should be simplified. | 7.1 | 0 | 21.9 | 78.1 Conclusion: Students enter medical school with widely differing levels of experience in conducting scholarly research, and the current Capstone course does not have flexibility for different types of projects, or the resources needed to accommodate student needs. Capstone affiliates and advisors also face difficulties providing optimal assistance to students. Through this work, I have identified solutions that are popular amongst students, which address unclear aspects of the Capstone course and top barriers to meeting deadlines. Bringing these solutions to the Capstone Course Leadership Team is the next step to addressing these concerns. Future goals include asking Capstone affiliates for their input, as this group was not included either in the oasis evaluations or the surveys. Another limitation of this study was the low survey response rates, ranging from 15-30%. I hope that ultimately some of these proposed changes to the Capstone course will be adopted and integrated into the new Vista curriculum.
-
The Impact of the COVID-19 Pandemic on the Clubhouse ModelThe COVID-19 pandemic posed challenges to the traditional Clubhouse Model of Psychosocial Rehabilitation (Clubhouse). The COVID-19 pandemic forced many Clubhouses around the world to rapidly pivot from face-to-face services and support programs at the Clubhouse to hybrid or virtual services. The Clubhouse community quickly mobilized to establish new structures to maintain connections with Clubhouse members and provide them with essential supports. This brief describes adaptations that Clubhouses made during the COVID-19 pandemic. We also describe supports offered by Clubhouse International to inform their international network about innovative approaches and best practices for Clubhouses during the COVID-19 pandemic.
-
Super large-bore ingestion of clot (SLIC) leads to high first pass effect in thrombectomy for large vessel occlusionBACKGROUND: Super large-bore aspiration (SLBA) has shown high rates of complete clot ingestion. OBJECTIVE: To report the initial clinical feasibility, safety, and efficacy of this novel SLBA insert combination-super large-bore ingestion of clot (SLIC) technique for stroke. METHODS: We performed a retrospective review of three comprehensive stroke center databases. The SLIC technique entails a triaxial assembly of an 8 Fr 0.106'' Base Camp catheter, 0.088'' catheter extender (HiPoint), and an insert catheter (Tenzing 8) that completely consumes the inner diameter of the 0.088'' SLBA catheter. The HiPoint catheter is delivered over the Tenzing 8 to the face of the embolus, which is withdrawn, while aspirating through the Base Camp and HiPoint catheters as a single assembly. RESULTS: Thirty-three consecutive patients with large vessel occlusion were treated with SLIC. The median age was 70 years (30-91) and 17 were male (51.5%). The median presenting National Institutes of Health Stroke Scale score and Alberta Stroke Program Early CT score was 21 (1-34) and 8 (5-10), respectively. There was 100% success in delivering the 0.088'' catheter to the site of the occlusion. The successful revascularization rate (modified Thrombolysis in Cerebral Infarction (mTICI) score > /=2B) was 100% within a single pass in most cases (82%). Final mTICI > /=2C was achieved in 94.1% of occlusions, with 73.5% mTICI 3 recanalization. The rate of first pass effect in achieving excellent reperfusion (mTICI > /=2C) was 70.5%. There were no adverse events or postprocedural symptomatic hemorrhages. CONCLUSIONS: Our initial experience with the SLIC technique resulted in achieving a first pass effect (mTICI > /=2C) in 70.5%. Navigation of the SLBA catheter extender over the Tenzing insert was successful and safe in this early experience.
-
Defining the substrate envelope of SARS-CoV-2 main protease to predict and avoid drug resistanceCoronaviruses can evolve and spread rapidly to cause severe disease morbidity and mortality, as exemplified by SARS-CoV-2 variants of the COVID-19 pandemic. Although currently available vaccines remain mostly effective against SARS-CoV-2 variants, additional treatment strategies are needed. Inhibitors that target essential viral enzymes, such as proteases and polymerases, represent key classes of antivirals. However, clinical use of antiviral therapies inevitably leads to emergence of drug resistance. In this study we implemented a strategy to pre-emptively address drug resistance to protease inhibitors targeting the main protease (M(pro)) of SARS-CoV-2, an essential enzyme that promotes viral maturation. We solved nine high-resolution cocrystal structures of SARS-CoV-2 M(pro) bound to substrate peptides and six structures with cleavage products. These structures enabled us to define the substrate envelope of M(pro), map the critical recognition elements, and identify evolutionarily vulnerable sites that may be susceptible to resistance mutations that would compromise binding of the newly developed M(pro) inhibitors. Our results suggest strategies for developing robust inhibitors against SARS-CoV-2 that will retain longer-lasting efficacy against this evolving viral pathogen.
