RSS 1.0eScholarship@UMassChan
eScholarship@UMassChan is a digital repository for UMass Chan Medical School's research and scholarship, including journal articles, theses, datasets and more. We welcome submissions from our faculty, staff, and students. eScholarship@UMassChan is a service of the Lamar Soutter Library, Worcester, MA, USA.
New! The recording and slides for our webinar "eScholarship@UMassChan: Share UMass Chan Research with the World" are available.
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
-
In the WeedsIntroduction: This week we will go multimedia and use a photo from Lisa Gussak, faculty member in our department. Lisa carries her camera often so she can take the "opportunity to observe the natural world, to see things as they appear in the moment and to reflect, all of which inform the care I provide to patients and their families." I appreciate her work (previously published this summer on Pulse.) About the photo, she wrote: This image reminds me how medicine and clinical problem solving often directs our thinking deep into the weeds of a problem or a patient’s presentation. This naturally obscures the background and may at times limit our ability to see the entire picture and the whole person. I also loved a comment on the site about her photo: This is a fabulous photograph. I think Dr. Gussak’s vision, both aesthetically and medically, is impressive. I wish more clinicians had this type of awareness.
-
Adulting Shorts: Passport to Adulting - Managing Your PaperworkThis info-comic is for youth and young adults with serious mental health conditions with tips about keeping and protecting important personal records and information. A tip sheet of this publication is also available for download https://doi.org/10.7191/pib.1062
-
White Coat CeremonyIntroduction: Welcome - and Welcome back to Family Medicine Moments. During this academic year you will receive a medical humanities piece each week on Thursday morning (unless it is a vacation week). These pieces are created by YOU! This is your forum. I created this listserv format over a decade ago so that we could celebrate the work and teaching we do at UMass Chan. I invite students, residents, faculty, staff to share your musings, essays, stories, poems, haiku, 55 and 6-word stories, music, photos, artwork, or something completely different. I ask that you remove any personal health information (PHI). Thanks for reading. Thanks for sharing. And now for week 1. This piece comes from a medical student who just arrived at UMass Chan! Prem Patel, Class of '27 shares with us a copy of the writing assignment for the White Coat Ceremony. Prem reflects on what the white coat represents and what it does not. I am reminded of an essay on the topic of "can medical students be taught compassion?". The white coat is a cloak that covers over the person who brings humanity to medical school in the first place. Let's all help Prem and the Class of '27 hang onto and foster that humanity. And be reminded of our own commitment to our helping profession as we see it through the eyes of a new member of our team.
-
Molecular Magnetic Resonance Imaging of Aneurysmal Inflammation Using a Redox Active Iron ComplexObjectives: Inflammation plays a key role in driving brain aneurysmal instability and rupture, but clinical tools to noninvasively differentiate between inflamed and stable aneurysms are lacking. We hypothesize that imaging oxidative changes in the aneurysmal microenvironment driven by myeloid inflammatory cells may represent a noninvasive biomarker to evaluate rupture risk. In this study, we performed initial evaluation of the oxidatively activated probe Fe-PyC3A as a tool for magnetic resonance imaging (MRI) of inflammation in a rabbit model of saccular aneurysm. Materials and methods: The difference in longitudinal relaxivity ( r1 ) in reduced and oxidized states of Fe-PyC3A was measured in water and blood plasma phantoms at 3 T. A rabbit saccular aneurysm model was created by endovascular intervention/elastinolysis with subsequent decellularization in situ. Rabbits were imaged at 4 weeks (n = 4) or 12 weeks (n = 4) after aneurysmal induction, when luminal levels of inflammation reflected by the presence of myeloperoxidase positive cells are relatively high and low, respectively, using a 3 T clinical scanner. Both groups were imaged dynamically using a 2-dimensional T1-weighted fast field echo pulse MRI sequence before and up to 4 minutes postinjection of Fe-PyC3A. Dynamic imaging was then repeated after an injection of gadobutrol (0.1 mmol/kg) as negative control probe. Rabbits from the 12-week aneurysm group were also imaged before and 20 minutes and 3 hours after injection of Fe-PyC3A using an axial respiratory gated turbo-spin echo (TSE) pulse sequence with motion-sensitized driven equilibrium (MSDE) preparation. The MSDE/TSE imaging was repeated before, immediately after dynamic acquisition (20 minutes postinjection), and 3 hours after injection of gadobutrol. Aneurysmal enhancement ratios (ERs) were calculated by dividing the postinjection aneurysm versus skeletal muscle contrast ratio by the preinjection contrast ratio. After imaging, the aneurysms were excised and inflammatory infiltrate was characterized by fluorometric detection of myeloperoxidase activity and calprotectin immunostaining, respectively. Results: In vitro relaxometry showed that oxidation of Fe-PyC3A by hydrogen peroxide resulted in a 15-fold increase of r1 at 3 T. Relaxometry in the presence of blood plasma showed no more than a 10% increase of r1 , indicating the absence of strong interaction of Fe-PyC3A with plasma proteins. Dynamic imaging with Fe-PyC3A generated little signal enhancement within the blood pool or adjacent muscle but did generate a transient increase in aneurysmal ER that was significantly greater 4 weeks versus 12 weeks after aneurysm induction (1.6 ± 0.30 vs 1.2 ± 0.03, P < 0.05). Dynamic imaging with gadobutrol generated strong aneurysmal enhancement, but also strong enhancement of the blood and muscle resulting in smaller relative ER change. In the 12-week group of rabbits, MSDE/TSE imaging showed that ER values measured immediately after dynamic MRI (20 minutes postinjection) were significantly higher ( P < 0.05) in the case of Fe-PyC3A (1.25 ± 0.06) than for gadobutrol injection (1.03 ± 0.03). Immunohistochemical corroboration using anticalprotectin antibody showed that leukocyte infiltration into the vessel walls and luminal thrombi was significantly higher in the 4-week group versus 12-week aneurysms (123 ± 37 vs 18 ± 7 cells/mm 2 , P < 0.05). Conclusions: Magnetic resonance imaging using Fe-PyC3A injection in dynamic or delayed acquisition modes was shown to generate a higher magnetic resonance signal enhancement in aneurysms that exhibit higher degree of inflammation. The results of our pilot experiments support further evaluation of MRI using Fe-PyC3A as a noninvasive marker of aneurysmal inflammation.
-
Advancing CRISPR-Cas Gene Editing Technologies: Engineering of Guide RNA, Donor Template, Editing Effector, and In Vivo DeliveryGene editing technologies have revolutionized various fields, from agriculture to medicine, by providing powerful tools to modify genetic materials. Early efforts, such as gene targeting, ZFN and TALEN, have laid the foundation for this field. In the past decade, CRISPR-Cas, derived from prokaryotic adaptive immune systems, has been re-engineered as gene editing tools, including nuclease editors, base editors, and prime editors. The simplicity, effectiveness, and versatility of these CRISPR-Cas gene editing tools have rapidly propelled their widespread use in both academia and industry. Despite the tremendous potential, many challenges arise during the development of CRISPR-Cas gene editing, and this thesis focuses on tackling some of the key ones. On one hand, I have dedicated my efforts to engineering gene editing components. This includes the synthesis of long guide RNA using click chemistry, enhancing the efficiency of homology-directed repair (HDR)-based editing using chemically modified donor templates, and improving modular prime editing platform by engineering effectors. On the other hand, I have also focused on the in vivo delivery of gene editors. Specifically, I have explored the first use of lipid nanoparticles for delivering chemically modified pegRNA and prime editor effector mRNA to achieve in vivo prime editing. Additionally, I have developed a fluorescence-based mouse reporter system to assess the in vivo performance of gene editors. Overall, the work presented in this thesis will greatly contribute to the advancement of CRISPR-Cas gene editing technologies, fostering progress in future research and therapeutic applications.
-
A Bacterial Pathogen Induces Reversible Developmental Slowing by High Reactive Oxygen Species and Mitochondrial Damage in Caenorhabditis ElegansHost-pathogen interactions are complex by nature, and the host developmental stage increases this complexity. Development is an energetically demanding period when biomass production and cell differentiation events occur. We investigated how a developing organism copes with the additional energy-expensive burden of pathogen stress during this crucial period. We explored this question by utilizing Caenorhabditis elegans larvae as the host and the bacterium Pseudomonas aeruginosa as the pathogen. By screening 36 P. aeruginosa isolates, we found that the CF18 strain causes a severe but reversible developmental delay. CF18 slows larval development via induction of reactive oxygen species (ROS) and mitochondrial dysfunction. In response, the larvae upregulate mitophagy and antimicrobial and detoxification genes; however, mitochondrial unfolded protein response (UPRmt) is repressed. Consistent with these observations, antioxidant or iron supplementation or the removal of larvae from CF18 rescues developmental delay, mitochondrial damage, and high ROS. We examined the virulence factors of CF18 required for developmental delay via transposon mutagenesis, RNA-sequencing, and candidate gene deletion approaches. Our results showed that virulence factors regulated by quorum sensing and the GacA/S system were responsible for developmental slowing. We also demonstrated that well-studied mitochondrial toxins of P. aeruginosa, phenazines and hydrogen cyanide, are not required for CF18-induced developmental slowing. This study highlights the importance of ROS levels and mitochondrial health as determinants of developmental rate and how pathogens can attack these important features.
-
A comparative analysis of microglial inducible Cre linesCre/loxP technology has revolutionized genetic studies and allowed for spatial and temporal control of gene expression in specific cell types. Microglial biology has particularly benefited because microglia historically have been difficult to transduce with virus or electroporation methods for gene delivery. Here, we investigate five of the most widely available microglial inducible Cre lines. We demonstrate varying degrees of recombination efficiency, cell-type specificity, and spontaneous recombination, depending on the Cre line and inter-loxP distance. We also establish best practice guidelines and protocols to measure recombination efficiency, particularly in microglia. There is increasing evidence that microglia are key regulators of neural circuits and major drivers of a broad range of neurological diseases. Reliable manipulation of their function in vivo is of utmost importance. Identifying caveats and benefits of all tools and implementing the most rigorous protocols are crucial to the growth of the field and the development of microglia-based therapeutics.
-
Resources for Addressing Food Insecurity and Other Social Determinants of Health in Worcester, MassachusettsSocial determinants of health (SDOH) are the environmental, social, and economic factors that can impact people’s quality of life and health. Examples of SDOH are where people live, the environment they live in, their employment and/or education, their socioeconomic status, and access to resources and basic needs such as food. Food insecurity is the lack of consistent access to enough affordable and nutritional food for every person in a household to live an active and healthy life. Food insecurity is a pressing issue in many areas including Central Massachusetts. Many communities and populations have experienced food insecurity, and these groups were especially affected during the COVID-19 pandemic. Challenges with food insecurity have also adversely affected people of color. This tip sheet is a list of resources available in the Worcester community to help families and community partners navigate local and state resources to address food insecurity and other social determinants of health.
-
TAL1 and LMO2 Promote Leukemia-Initiating Cell Quiescence and Chemotolerance in T-ALLRelapse remains a major barrier to the successful treatment of children with T-cell acute lymphoblastic leukemia (T-ALL) and may represent a failure to eliminate leukemia-initiating cells (L-ICs) that possess distinguishing biological features from the bulk leukemic population. TAL1 and LMO2 are often coordinately misexpressed in T-ALL patients and their ectopic expression cooperates to transform thymic progenitors in mice. In this model, double negative-3 (DN3) stage thymic progenitors harbor L-ICs, yet only a subset of DN3 leukemic cells have L-IC activity. We interrogated L-IC heterogeneity in our Tal1/Lmo2 mouse T-ALL model using a combination of single cell RNA-sequencing (scRNA-seq) and H2B-GFP nucleosome labeling. We identified a cell cycle restricted DN3 subpopulation with high Notch1 activity and enrichment of Tal1/Lmo2 targets and T-cell quiescence genes. This dormant DN3 population significantly increased during leukemogenesis, exhibited chemotolerance and was enriched for genes associated with patient minimal residual disease (MRD). In vivo studies using the Tet-inducible H2B-GFP model revealed that Tal1 and Lmo2 cooperate to promote quiescence in DN3 cells. Examination of TAL1/LMO patient samples revealed that the L-IC enriched CD7+CD1a- thymic progenitors (hL-IC) were also chemotolerant and were also variably associated with quiescence. Collectively, our results document the emergence of dormant and chemotolerant L-ICs during Tal1/Lmo2-induced leukemogenesis in mice and relapsed T-ALL patients.
-
The Post-Transcriptional Regulation Mechanism and Functional Importance of a Key Maternal mRNA, GLP-1Translational control of maternal mRNAs is a major form of gene regulation during germline development and embryogenesis. C. elegans Notch homolog glp-1 maternal gene is necessary for germ cell proliferation, and embryonic fate determination. The RNA binding proteins POS-1 and GLD-1 directly regulate the translation of GLP-1 protein by binding to the specific elements within the glp-1 3’ UTR. When POS-1 or GLD-1 binding is disrupted by mutation of their respective elements, the expression pattern of a glp-1 3’ UTR reporter transgene changes in both the germline and in embryos. The mechanism by which POS-1 and GLD-1 mediate translation repression is not well understood. Previous work showed that loss of pos-1 increases the average polyA tail length of endogenous glp-1 transcripts in embryos. In this dissertation, we show that mutation of either the GLD-1 or POS-1 binding motifs in transgenic reporters does not change polyA site selection. This result rules out alternative polyA site selection as a mechanism of regulation. We also show that wild-type glp-1 transgenic reporter embryos have a shorter average polyA tail length compared to transgenic reporters with mutated GLD-1 or POS-1 binding motifs. We have studied the effect of cytoplasmic polymerases, deadenylases and translation initiation factors on our transgenic reporters. Our RNAi experiments show that two cytoplasmic polyA polymerases, GLD-2 and GLD-4, have strikingly different effects on the expression of reporter transgenes harboring GLD-1 or POS-1 binding motif mutations. By contrast, none of the deadenylases affect the transgenic reporter expression. We also observed strong derepression of all reporters upon reduction of the translation initiation factor ife-3. The results reveal that POS-1 and GLD-1 exert their repressive effects in different ways through cytoplasmic polyA polymerase activity, while IFE-3 mediated translation repression is independent of both POS-1 and GLD-1. Lastly, we have examined the biological significance of glp-1 3’UTR to the worm reproduction by using CRISPR/Cas9 mutagenesis to generate glp-1 3’UTR mutations in the endogenous locus. Characterization of a 71 base pair mutation that deletes the GLD-1 and POS-1 binding sites in the glp-1 3’UTR reveals a 2-fold reduction in the number of embryos produced and a 4-fold reduction in the hatch rate. Imaging results show that the mutant embryos appear to have patterning defects. Together, our results show that the glp-1 3’UTR contributes to reproductive health but is not essential to fertility.
-
Nurses with Physical Disabilities Experiences During Pre-licensure EducationPURPOSE: To describe the pre-licensure nursing educational experience of integration and inclusion among RNs with a physical disability during their education. SPECIFIC AIMS: 1) Describe the access RNs with a physical disability had to academic and social opportunities during their prelicensure education program that contributed to academic and social integration (inclusion). 2). Explore perceptions of RNs with a physical disability regarding inclusion and acceptance of their disability as a valued component of student diversity during their prelicensure education program. 3). Describe the contextual factors and key aspects of connection during the pre-licensure educational experiences of RNs who had a physical disability as positive (Disability-Diversity Connect) or negative and disintegrated (Disability-Diversity Disconnect). FRAMEWORK: This study was guided by The Disability-Diversity Disconnect (DDDM) by Aquino (2016). DESIGN: This study design used was qualitative description. It included semi-structured interviews using an interview guide based on the DDDM. RESULTS: 16 individuals with 14 different physical disabilities participated in this study. During data analysis four themes emerged: I Saved My Energy for Learning, Determination, Wanting to Find My People and Secrets, Living a Double Life which has a subtheme, Fear of Judgement. CONCLUSION: : Identification of factors related to inclusion within the academic environment provides insight for future work to examine the needs of prelicensure nursing students with physical disabilities and the potential to improve their future educational experiences.
-
National Public Health Coordination Office (NPHCO) Annual Report 2022-2023This annual report is presented under NNLM format guidelines. The National Public Health Coordination Office facilitates NNLM's response to the information needs of the public health workforce through two program areas: Public Health Digital Library and National Public Health Engagement.
-
UMCCTS Newsletter, August 2023This is the August 2023 issue of the UMass Center for Clinical and Translational Science Newsletter containing news and events of interest.
-
A novel intrasaccular aneurysm device with high complete occlusion rate: initial results in a rabbit modelBackground: Intrasaccular flow-disrupting devices are a safe and effective treatment strategy for intracranial aneurysms. We utilized high-frequency optical coherence tomography (HF-OCT) and digital subtraction angiography (DSA) to evaluate SEAL Arc, a new intrasaccular device, and compare the findings with the well-established Woven EndoBridge (WEB) device in an animal model of saccular aneurysms. Methods: In a rabbit model, elastase-induced aneurysms were treated with SEAL Arc (n=11) devices. HF-OCT and DSA were performed after implant and repeated after 12 weeks. Device protrusion and malapposition were assessed at implant time and scored on a binary system. Aneurysm occlusion was assessed at 12 weeks with the WEB Occlusion Scale and dichotomized to complete (A and B) or incomplete (C and D) occlusion. The percentage of neointimal coverage after 12 weeks was quantified using HF-OCT. We compared these data to previously published historical controls treated with the gold-standard WEB device (n=24) in the same model. Results: Aneurysm size and device placement were not significantly different between the two groups. Complete occlusion was demonstrated in 80% of the SEAL Arc devices, which compared favorably to the 21% of the aneurysms treated with WEB devices (P=0.002). Neointimal coverage across SEAL Arc devices was 86±15% compared with 49±27% for WEB (P=0.001). Protruding devices had significantly less neointimal coverage (P<0.001) as did incompletely occluded aneurysms (P<0.001). Histologically, all aneurysms treated with SEAL Arc devices were completely healed. Conclusion: Complete early aneurysm occlusion was frequently observed in the SEAL Arc treated aneurysms, with significant neointimal coverage after 12 weeks.
-
Life-Limiting Peripheral Organ Dysfunction in Feline Sandhoff Disease Emerges after Effective CNS Gene TherapyObjective: GM2 gangliosidosis is usually fatal by 5 years of age in its 2 major subtypes, Tay-Sachs and Sandhoff disease. First reported in 1881, GM2 gangliosidosis has no effective treatment today, and children succumb to the disease after a protracted neurodegenerative course and semi-vegetative state. This study seeks to further develop adeno-associated virus (AAV) gene therapy for human translation. Methods: Cats with Sandhoff disease were treated by intracranial injection of vectors expressing feline β-N-acetylhexosaminidase, the enzyme deficient in GM2 gangliosidosis. Results: Hexosaminidase activity throughout the brain and spinal cord was above normal after treatment, with highest activities at the injection sites (thalamus and deep cerebellar nuclei). Ganglioside storage was reduced throughout the brain and spinal cord, with near complete clearance in many regions. While untreated cats with Sandhoff disease lived for 4.4 ± 0.6 months, AAV-treated cats lived to 19.1 ± 8.6 months, and 3 of 9 cats lived >21 months. Correction of the central nervous system was so effective that significant increases in lifespan led to the emergence of otherwise subclinical peripheral disease, including megacolon, enlarged stomach and urinary bladder, soft tissue spinal cord compression, and patellar luxation. Throughout the gastrointestinal tract, neurons of the myenteric and submucosal plexuses developed profound pathology, demonstrating that the enteric nervous system was inadequately treated. Interpretation: The vector formulation in the current study effectively treats neuropathology in feline Sandhoff disease, but whole-body targeting will be an important consideration in next-generation approaches. ANN NEUROL 2023.
-
Respiratory signal estimation for cardiac perfusion SPECT using deep learningBackground: Respiratory motion induces artifacts in reconstructed cardiac perfusion SPECT images. Correction for respiratory motion often relies on a respiratory signal describing the heart displacements during breathing. However, using external tracking devices to estimate respiratory signals can add cost and operational complications in a clinical setting. Purpose: We aim to develop a deep learning (DL) approach that uses only SPECT projection data for respiratory signal estimation. Methods: A modified U-Net was implemented that takes temporally finely sampled SPECT sub-projection data (100 ms) as input. These sub-projections are obtained by reframing the 20-s list-mode data, resulting in 200 sub-projections, at each projection angle for each SPECT camera head. The network outputs a 200-time-point motion signal for each projection angle, which was later aggregated over all angles to give a full respiratory signal. The target signal for DL model training was from an external stereo-camera visual tracking system (VTS). In addition to comparing DL and VTS, we also included a data-driven approach based on the center-of-mass (CoM) strategy. This CoM method estimates respiratory signals by monitoring the axial changes of CoM for counts in the heart region of the sub-projections. We utilized 900 subjects with stress cardiac perfusion SPECT studies, with 302 subjects for testing and the remaining 598 subjects for training and validation. Results: The Pearson's correlation coefficient between the DL respiratory signal and the reference VTS signal was 0.90, compared to 0.70 between the CoM signal and the reference. For respiratory motion correction on SPECT images, all VTS, DL, and CoM approaches partially de-blured the heart wall, resulting in a thinner wall thickness and increased recovered maximal image intensity within the wall, with VTS reducing blurring the most followed by the DL approach. Uptake quantification for the combined anterior and inferior segments of polar maps showed a mean absolute difference from the reference VTS of 1.7% for the DL method for patients with motion >12 mm, compared to 2.6% for the CoM method and 8.5% for no correction. Conclusion: We demonstrate the capability of a DL approach to estimate respiratory signal from SPECT projection data for cardiac perfusion imaging. Our results show that the DL based respiratory motion correction reduces artefacts and achieves similar regional quantification to that obtained using the stereo-camera VTS signals. This may enable fully automatic data-driven respiratory motion correction without relying on external motion tracking devices.
-
Children's Oncology Group's 2023 blueprint for research: Radiation oncologyRadiation oncology is an integral part of the multidisciplinary team caring for children with cancer. The primary goal of our committee is to enable the delivery of the safest dose of radiation therapy (RT) with the maximal potential for cure, and to minimize toxicity in children by delivering lower doses to normal tissues using advanced technologies like intensity-modulated RT (IMRT) and proton therapy. We provide mentorship for y ators and are actively involved in educating the global radiation oncology community. We are leaders in the effort to discover novel radiosensitizers, radioprotectors, and advanced RT technologies that could help improve outcomes of children with cancer.
-
Systems neuroscience: Foraging through serotonin's tangled webSerotonin signaling is conserved in regulating animal behaviors. A new paper decodes the nonlinear effects of all serotonin receptor combinations on foraging behaviors. The authors introduce a brain-wide multiscale method to dissect receptor dynamics, receptor effects on neural activity, and resulting behavioral changes.
-
Pediatric High Blood Pressure Follow-up Guideline Adherence in a Massachusetts Healthcare SystemObjectives: To describe adherence to the American Academy of Pediatrics' (AAP) 2017 clinical practice guidelines for follow-up after high blood pressure (BP) screening by pediatric and family medicine providers in a Massachusetts healthcare system and to assess differences in receipt of follow-up according to child- and clinic-level factors. Methods: Electronic health record data were analyzed for children aged 3-17 years who had an outpatient primary care visit during 2018 with a high BP screening (according to AAP guidelines). We classified AAP guideline adherent follow-up as BP follow-up within 6 months after an elevated finding (+2-week buffer) and within 2 weeks after a hypertensive finding (+2-week buffer). Differences in receipt of guideline adherent follow-up by child- and clinic-level factors were assessed via multilevel mixed effects logistic regression models. Results: The median age of the 4,563 included children was 12 years and 43% were female. Overall, guideline adherent follow-up was received by 17.7% of children within the recommended time interval; 27.4% for those whose index BP was elevated and 5.4% for those whose BP was hypertensive. Modeling revealed older children and those belonging to clinics with more providers, smaller patient panels, and smaller proportion of Medicaid patients were more likely to receive adherent follow-up. Conclusion: Few children received guideline adherent BP follow-up and most differences in adherence were related to clinic resources. System level interventions are needed to improve BP follow-up.
-
Caffeine intoxication treated with hemodialysisIntroduction: Caffeine overdose, while uncommon, can be life threatening with hemodynamic and neurological complications and often requires intensive monitoring and critical management. Case report: We report a case of a 23-year-old male who ingested approximately 24 g of caffeine in a suicidal attempt and developed cardiopulmonary complications. He was resuscitated, and hemodialysis was performed with successful recovery. Conclusion: Hemodialysis appears to effectively remove caffeine from the blood system and can be lifesaving in severe caffeine overdose.
