Biochemistry, Biophysics, and Structural Biology Commons^™

The Role Of Sugars In Aggregation Of The Protein Kassinin, Lillie G. Waldron

Student Summer Scholars Manuscripts

The aggregation of proteins to form amyloids is implicated in several diseases such as Alzheimer’s Disease, Parkinson’s Disease, and many others. This aggregation has several stages, progressing from isolated protein molecules (monomers) to small aggregates (oligomers), which are toxic to cells, and finally to large, string-like mature aggregates. Despite this association with disease, functional amyloids, which have normal biological functions, also result from protein aggregation. Kassinin, an amphibian peptide involved in nerve signal transmission, is a model system for functional amyloid study. To compare the aggregation of functional and disease-causing amyloids, we previously synthesized a fluorine-labeled kassinin through solid-phase peptide …

Emerging Chromatin Regulators In Response To Heavy Metal Exposure, Wesley Saintilnord

Theses and Dissertations--Molecular and Cellular Biochemistry

Environmental exposure to heavy metals poses significant threats to human health as they are associated with various developmental and chronic pathologies such as reproductive defects and cancers. Despite their profound risks, a comprehensive understanding of their disease-causing mechanisms is lacking. Most studies point to reactive oxygen species-induced DNA damage; however, their mutagenic potential is relatively weak suggesting the involvement of alternative mechanisms. One important, yet underexplored mechanism, is their ability to rewire the epigenome via DNA methylation and histone variant incorporation, leading to aberrant gene regulatory networks.

This study investigates the epigenetic mechanisms targeted by two ubiquitous heavy metals with …

The Study Of Ribosome-Amplified Metabolism, Rambo, Effect In Vitro And In Live Cells, Jianchao Yu

Electronic Theses & Dissertations (2024 - present)

Quinary interactions arise due to the extreme macromolecular crowding inside live cells. Quinary interactions affect intracellular protein stability, activity, and homeostasis. Ribosomes, traditionally known for their role in protein synthesis, have been found to engage in quinary interactions with metabolic enzymes, modulating their activity and thereby revealing a potential regulatory role for ribosomes in cellular metabolism. This phenomenon, termed the Ribosome-Amplified MetaBOlism (RAMBO) effect, was investigated in this dissertation through a series of in vitro and in vivo studies using primarily Nuclear Magnetic Resonance (NMR) spectroscopy.

Firstly, an NMR-based direct enzyme assay compatible with ribosome was developed and validated using …

Exploring The Effects Of Choline Treatment On Dystrophic Phenotype, Brooklyn Morris

Browse all Theses and Dissertations

Duchenne Muscular Dystrophy (DMD) is a devastating progressive muscular disorder caused by a mutation in the dystrophin gene affecting approximately 1 in 3,500 males. However, despite its prevalence, there is currently no cure for this disease. Mutations in dystrophin lead to enhanced inflammation, fibrosis, cell death, development, and decreased skeletal muscle function. Phosphatidylcholine, synthesized by choline, is a major phospholipid that functions in maintaining and synthesizing cell membranes and has previously been found to be decreased in DMD patients. This led us to hypothesize that the dystrophic phenotype could be improved through treatment with choline. In this study, we used …

A Multimolecular Perspective On The Success Of Wolf Recovery And Relocation, Samuel D. Hervey

Dissertations, Master's Theses and Master's Reports

With global biodiversity in decline and many species isolated in fragmented habitats, conservation efforts increasingly rely on natural recolonization and translocation to restore ecosystems. These strategies face challenges such as genetic erosion and habitat limitations, highlighting the need for effective monitoring practices. This research assesses the success of wolf recovery initiatives by examining long-term genetic and genomic health using both traditional and advanced molecular methods. First, we investigated the genetic health of 19 gray wolves (Canis lupus) relocated to Isle Royale National Park to restore ecosystem balance. Initial genetic assessments with microsatellites found that these wolves had genetic diversity metrics …

Synthesis Of Long Oligodeoxynucleotides, Yipeng Yin

Dissertations, Master's Theses and Master's Reports

Synthetic long oligodeoxynucleotides (ODNs) have found wide applications in diverse fields such as chemical biology, synthetic biology, and genes and genomes synthesis. Those applications leading to a significant demand for their production. However, traditional methods for purifying synthetic ODNs present notable drawbacks, particularly their inability to purify long ODNs, rendering long ODN synthesis challenging. To address these issues, chemical synthesis techniques for long ODNs coupled with non-chromatographic purification methods have been developed. This technology makes the purification of long synthetic ODNs feasible and offers a viable pathway for producing genes and genomes with extensive repeats or stable secondary structures, which …

Exploring The Molecular Pathways Of Cell Death Induced By Pde3 Modulators, Aqsa Ahsan

Dissertations, Master's Theses and Master's Reports

Metabolic dysregulation, a critical hallmark of cancer, predisposes potential vulnerabilities for the development of targeted therapy. LKB1, a pivotal metabolic regulator and tumor suppressor, is often lost in many cancers. Our laboratory has unveiled that LKB1 suppresses phosphodiesterases (PDEs), and PDE3 modulators can selectively eradicate LKB1-deficient tumor cells. Through metabolic gene sgRNA library screening, Sarcolipin, an inhibitor of Sarcoendoplasmic Reticulum Calcium ATPase (SERCA), emerged as essential for cell death in this context. However, the precise molecular mechanisms by which PDE3 modulators exert their effects remain elusive. This study aims to uncover these mechanisms via RNA-Seq profiling and differential gene analysis, …

Hybridization Kinetics Of Four-Way Junctions Localized On A Dna Scaffold, Katherine N. Taylor

Honors Undergraduate Theses

DNA computing is an ever-growing field with scientists trying to design structures that optimize logic gate communication to develop fast, biologically compatible, computational structures. We hypothesize that by using the principles of DNA computing, it is possible to design a DNA tile capable of studying localized DNA hybridization that can differentiate between oligonucleotides of different structural conformations. This includes synthetically manipulating DNA into a nanostructure that can perform Boolean logic functions to calculate the different rates of hybridization. To test our hypothesis, we designed a DNA Tile that incorporated a 4WJ using YES logic. Linear and hairpin single-stranded (ss) DNA …

The Evolution Of The Metazoan Circadian Molecular Mechanism And The Conservation Of Canonical Circadian Elements, Olivia Waldridge

Theses and Dissertations--Biology

The temporal organization of biological activities through circadian rhythms is pivotal for the survival of organisms. Significant progress has been made in understanding the molecular foundations of animal circadian clocks through the characterization of key components such as Clock, Bmal1/Cycle(Cyc), Period (Per), Timeless, and Cryptochrome (Cry) in several model organisms. To determine the universality of this conservation, we investigated the sequences of these genes and their paralogs across 46 animal species that encompass multiple phyla in the metazoan kingdom to resolve the relative timing of duplication and loss events that have diversified core clock components in the metazoan kingdom. Using …

The Carboxy Terminus Causes Interfacial Assembly Of Oleate Hydratase On A Membrane Bilayer, Christopher D. Radka, Christy R. Grace, Hale S. Hasdemir, Yupeng Li, Carlos C. Rodriguez, Patrick Rodrigues, Michael L. Oldham, M. Zuhaib Qayyum, Aaron Pitre, William J. Maccain, Ravi C. Kalathur, Emad Tajkhorshid, Charles O. Rock

Markey Cancer Center Faculty Publications

The soluble flavoprotein oleate hydratase (OhyA) hydrates the 9-cis double bond of unsaturated fatty acids. OhyA sub- strates are embedded in membrane bilayers; OhyA must remove the fatty acid from the bilayer and enclose it in the active site. Here, we show that the positively charged helix- turn-helix motif in the carboxy terminus (CTD) is responsible for interacting with the negatively charged phosphatidylgly- cerol (PG) bilayer. Super-resolution microscopy of Staphylo- coccus aureus cells expressing green fluorescent protein fused to OhyA or the CTD sequence shows subcellular localization along the cellular boundary, indicating OhyA is membrane- associated and the CTD sequence …

Strategies For Improving The Performance Of Prediction Models For Response To Immune Checkpoint Blockade Therapy In Cancer, Tiantian Zeng, Jason Z. Zhang, Arnold Stromberg, Jin Chen, Chi Wang

Markey Cancer Center Faculty Publications

Immune checkpoint blockade (ICB) therapy holds promise for bringing long-lasting clinical gains for the treatment of cancer. However, studies show that only a fraction of patients respond to the treatment. In this regard, it is valu- able to develop gene expression signatures based on RNA sequencing (RNAseq) data and machine learning meth- ods to predict a patient’s response to the ICB therapy, which contributes to more personalized treatment strategy and better management of cancer patients. However, due to the limited sample size of ICB trials with RNAseq data available and the vast number of candidate gene expression features, it is …

Vaginal Lactobacillus Fatty Acid Response Mechanisms Reveal A Metabolite-Targeted Strategy For Bacterial Vaginosis Treatment, Paul C. Blainey, Seth M. Bloom, Douglas S. Kwon

Markey Cancer Center Faculty Publications

Bacterial vaginosis (BV), a common syndrome characterized by Lactobacillus-deficient vaginal microbiota, is associated with adverse health outcomes. BV often recurs after standard antibiotic therapy in part because antibiotics promote microbiota dominance by Lactobacillus iners instead of Lactobacillus crispatus, which has more beneficial health associations. Strategies to promote L. crispatus and inhibit L. iners are thus needed. We show that oleic acid (OA) and similar long-chain fatty acids simultaneously inhibit L. iners and enhance L. crispatus growth. These phenotypes require OA-inducible genes conserved in L. crispatus and related lactobacilli, including an oleate hydratase (ohyA) and putative fatty acid efflux pump (farE). …

Elevated Free Cholesterol Levels Due To Impaired Reverse Cholesterol Transport Are A Risk Factor For Polymicrobial Sepsis In Mice, Qian Wang, Ling Guo, Dan Hao, Misa Ito, Chieko Mineo, Philip W. Shaul, Xiang-An Li

Markey Cancer Center Faculty Publications

Dysregulated lipid metabolism is commonly observed in septic patients, but how it contributes to sepsis remains largely unknown. Reverse cholesterol transport (RCT) is crucial for regulating cholesterol metabolism in circulation. During RCT, high-density lipoprotein collects cholesterol from peripheral tissues and transports it to the liver’s scavenger receptor BI (SR- BI), where SR-BI mediates the uptake of cholesteryl esters (CEs) from high-density lipoprotein for excretion via bile. In this study, we utilized AlbCreSR-BIfl/fl mice, a model with impaired RCT, to investigate the impact of RCT on sepsis. We found that AlbCreSR-BIfl/fl mice were significantly more susceptible to cecal ligation and puncture …

Nudcl2 Is Required For Cytokinesis By Stabilizing Rcc2 With Hsp90 At The Midbody, Xiaoyang Xu, Yuliang Huang, Feng Yang, Xiaoxia Sun, Rijin Lin, Jiaxing Feng, Mingyang Yang, Jiaqi Shao, Xiaoqi Liu, Tianhua Zhou, Shanshan Xie, Yuehong Yang

Markey Cancer Center Faculty Publications

Cytokinesis is required for faithful division of cytoplasmic components and duplicated nuclei into two daughter cells. Midbody, a protein-dense organelle that forms at the intercellular bridge, is indispensable for success- ful cytokinesis. However, the regulatory mechanism of cytokinesis at the midbody still remains elusive. Here, we unveil a critical role for NudC-like protein 2 (NudCL2), a co-chaperone of heat shock protein 90 (Hsp90), in cytokinesis regulation by stabilizing regulator of chromosome condensation 2 (RCC2) at the midbody in mam- malian cells. NudCL2 localizes at the midbody, and its downregulation results in cytokinesis failure, multinu- cleation, and midbody disorganization. Using iTRAQ-based …

Enhancing Translation: A Need To Leverage Complex Preclinical Models Of Addictive Drugs To Accelerate Substance Use Treatment Options, Christa Corley, Ashley Craig, Safiyah M. Sadek, Julie A. Marusich, Samar N. Chehimi, Ashley M. White, Lexi J. Holdiness, Benjamin C. Reiner, Cassandra D. Gipson

Markey Cancer Center Faculty Publications

Preclinical models of addictive drugs have been developed for decades to model aspects of the clinical experience in substance use disorders (SUDs). These include passive exposure as well as volitional intake models across addictive drugs and have been utilized to also measure withdrawal symptomatology and potential neuro- behavioral mechanisms underlying relapse to drug seeking or taking. There are a number of Food and Drug Administration (FDA)-approved medications for SUDs, however, many demonstrate low clinical efficacy as well as potential sex differences, and we also note gaps in the continuum of care for certain aspects of clinical ex- periences in individuals …

Biliverdin Reductase-A Integrates Insulin Signaling With Mitochondrial Metabolism Through Phosphorylation Of Gsk3Β, Chiara Lanzillotta, Antonella Tramutola, Simona Lanzillotta, Viviana Greco, Sara Pagnotta, Caterina Sanchini, Silvia Di Angelantonio, Elena Forte, Serena Rinaldo, Alessio Paone, Francesca Cutruzzolà, Flavia Agata Cimini, Ilaria Barchetta, Maria Gisella Cavallo, Andrea Urbani, D. Allan Butterfield, Fabio Di Domenico, Bindu D. Paul, Marzia Perluigi, Joao M.N. Duarte

Markey Cancer Center Faculty Publications

Brain insulin resistance links the failure of energy metabolism with cognitive decline in both type 2 Diabetes Mellitus (T2D) and Alzheimer’s disease (AD), although the molecular changes preceding overt brain insulin resistance remain unexplored. Abnormal biliverdin reductase-A (BVR-A) levels were observed in both T2D and AD and were associated with insulin resistance. Here, we demonstrate that reduced BVR-A levels alter insulin signaling and mitochondrial bioenergetics in the brain. Loss of BVR-A leads to IRS1 hyper-activation but dys- regulates Akt-GSK3β complex in response to insulin, hindering the accumulation of pGSK3βS9 into the mito- chondria. This event impairs oxidative phosphorylation and fosters …

Therapeutic Potential Of Berberine In Attenuating Cholestatic Liver Injury: Insights From A Psc Mouse Model, Yanyan Wang, Derrick Zhao, Lianyong Su, Yun-Ling Tai, Grayson W. Way, Jing Zeng, Qianhua Yan, Ying Xu, Xuan Wang, Emily C. Gurley, Xi-Qiao Zhou, Jinze Liu, Jinpeng Liu, Weidong Chen, Philip B. Hylemon, Huiping Zhou

Markey Cancer Center Faculty Publications

Background and aims

Primary sclerosing cholangitis (PSC) is a chronic liver disease characterized by progressive biliary inflammation and bile duct injury. Berberine (BBR) is a bioactive isoquinoline alkaloid found in various herbs and has multiple beneficial effects on metabolic and inflammatory diseases, including liver diseases. This study aimed to examine the therapeutic effect of BBR on cholestatic liver injury in a PSC mouse model (Mdr2 −/− mice) and eluci‑ date the underlying mechanisms.

Methods

Mdr2−/− mice (12–14 weeks old, both sexes) received either BBR (50 mg/kg) or control solution daily for eight weeks via oral gavage. Histological and serum biochemical …

Mechanisms Of Γδ T Cell Accumulation In Visceral Adipose Tissue With Aging, Sujata Mukherjee, Maria E. C. Bruno, Jason Oakes, Gregory S. Hawk, Arnold Stromberg, Donald A. Cohen, Marlene E. Starr

Markey Cancer Center Faculty Publications

γδ T cells are resident in visceral adipose tissue (VAT) where they show an age- associated increase in numbers and contribute to local and systemic chronic inflammation. However, regulation of this population and mechanisms for the age-dependent accumulation are not known. In this study, we identified a progressive trend of γδ T cell accumulation in VAT over the lifespan in mice and explored physiological mechanisms contributing to accumulation. Using isochronic parabiotic pairs of wild-type (WT) and T cell receptor delta knockout (TCRδ KO) mice at young and old age, we confirmed that VAT γδ T cells are predominately a tissue-resident …

A Novel Protozoa Parasite-Derived Protein Adjuvant Is Effective In Immunization With Cancer Cells To Activate The Cancer-Specific Protective Immunity And Inhibit The Cancer Growth In A Murine Model Of Colorectal Cancer, Rajesh Mani, Chloe G. Martin, Kanal E. Balu, Qingding Wang, Piotr G. Rychahou, Tadahide Izumi, B. Mark Evers, Yasuhiro Suzuki

Markey Cancer Center Faculty Publications

Cancer-specific CD8+ cytotoxic T cells play important roles in preventing cancer growth, and IFN-γ, in addition to IL-12 and type I interferon, is critical for activating CD8+ cytotoxic T cells. We recently identified the capability of the amino-terminus region of dense granule protein 6 (GRA6Nt) of Toxoplasma gondii, an intracellular protozoan parasite, to activate IFN-γ production of microglia, a tissue-resident macrophage population. Therefore, in the present study, we examined whether recombinant GRA6Nt protein (rGRA6Nt) functions as an effective adjuvant to potently activate cancer-specific protective immunity using a murine model of MC38 colorectal cancer (CRC). When mice were immunized with non-replicable …

Structure, Dynamics, And Redox Reactivity Of An All-Purpose Flavodoxin, Sharique Khan, Ahmadullah Ansari, Monica Brachi, Debarati Das, Wassim El Housseini, Shelley Minteer, Anne-Francis Miller

Markey Cancer Center Faculty Publications

The flavodoxin of Rhodopseudomonas palustris CGA009 (Rp9Fld) supplies highly reducing equivalents to crucial en- zymes such as hydrogenase, especially when the organism is iron-restricted. By acquiring those electrons from photodriven electron flow via the bifurcating electron transfer flavoprotein, Rp9Fld provides solar power to vital metabolic processes. To understand Rp9Fld’s ability to work with diverse partners, we solved its crystal structure. We observed the canonical fla- vodoxin (Fld) fold and features common to other long-chain Flds but not all the surface loops thought to recognize part- ner proteins. Moreover, some of the loops display alternative structures and dynamics. To advance studies …

Sedimentation Of Large, Soluble Proteins Up To 140 Kda For 1h-Detected Mas Nmr And 13c Dnp Nmr – Practical Aspects, Dallas Bell, Florian Lindemann, Lisa Gerland, Hanna Aucharova, Alexander Klein, Daniel Friedrich, Matthias Hiller, Kristof Grohe, Tobias Meier, Barth Van Rossum, Anne Diehl, Jon Hughes, Leonard J. Mueller, Rasmus Linser, Anne-Frances Miller, Hartmut Oschkinat

Markey Cancer Center Faculty Publications

Solution NMR is typically applied to biological systems with molecular weights < 40 kDa whereas magic-angle-spinning (MAS) solid-state NMR traditionally targets very large, oligomeric proteins and complexes exceeding 500 kDa in mass, including fibrils and crystalline protein preparations. Here, we propose that the gap between these size regimes can be filled by the approach presented that enables investigation of large, soluble and fully protonated proteins in the range of 40–140 kDa. As a key step, ultracentrifugation produces a highly concentrated, gel-like state, resembling a dense phase in spontaneous liquid-liquid phase separation (LLPS). By means of three examples, a Sulfolobus acidocaldarius bifurcat- ing electron transfer flavoprotein (SaETF), tryptophan synthases from Salmonella typhimurium (StTS) and their dimeric β-subunits from Pyrococcus furiosus (PfTrpB), we show that such samples yield well-resolved proton-detected 2D and 3D NMR spectra at 100 kHz MAS without heterogeneous broadening, similar to diluted liquids. Herein, we provide practical guidance on centrifugation conditions and tools, sample behavior, and line widths expected. We demonstrate that the observed chemical shifts correspond to those obtained from μM/low mM solutions or crystalline samples, indicating structural integrity. Nitrogen line widths as low as 20–30 Hz are observed. The presented approach is advantageous for proteins or nucleic acids that cannot be deuterated due to the expression system used, or where relevant protons cannot be re-incorporated after expression in deuterated medium, and it circumvents crystallization. Importantly, it allows the use of low-glycerol buffers in dynamic nuclear polarization (DNP) NMR of proteins as demonstrated with the cyanobacterial phytochrome Cph1.

Non-Transcriptional Irf7 Interacts With Nf-Κb To Inhibit Viral Inflammation, Shumin Fan, Sonam Popli, Sukanya Chakravarty, Ritu Chakravarty, Saurabh Chattopadhyay

Markey Cancer Center Faculty Publications

Interferon (IFN) regulatory factors (IRF) are key transcrip- tion factors in cellular antiviral responses. IRF7, a virus- inducible IRF, expressed primarily in myeloid cells, is required for transcriptional induction of interferon α and antiviral genes. IRF7 is activated by virus-induced phosphory- lation in the cytoplasm, leading to its translocation to the nu- cleus for transcriptional activity. Here, we revealed a nontranscriptional activity of IRF7 contributing to its antiviral functions. IRF7 interacted with the pro-inflammatory tran- scription factor NF-κB-p65 and inhibited the induction of in- flammatory target genes. Using knockdown, knockout, and overexpression strategies, we demonstrated that IRF7 inhibited NF-κB–dependent inflammatory …

Foxs1 Is Increased In Liver Fibrosis And Regulates Tgfβ Responsiveness And Proliferation Pathways In Human Hepatic Stellate Cells, Evelyn A. Bates, Zachary A. Kipp, Wang-Hsin Lee, Genesee J. Martinez, Lauren Weaver, Kathryn N. Becker, Sally Pauss, Justin F. Creeden, Garrett B. Anspach, Robert N. Helsley, Mei Xu, Maria E. C. Bruno, Marlene E. Starr, Terry D. Hinds Jr.

Markey Cancer Center Faculty Publications

Liver fibrosis commences with liver injury stimulating transforming growth factor beta (TGFβ) activation of hepatic stellate cells (HSCs), causing scarring and irreversible damage. TGFβ induces expression of the transcription factor Forkhead box S1 (FOXS1) in hepatocytes and may have a role in the pathogenesis of hepatocellular carcinoma (HCC). To date, no studies have determined how it affects HSCs. We analyzed human livers with cirrhosis, HCC, and a murine fibrosis model and found that FOXS1 expression is significantly higher in fibrotic livers but not in HCC. Next, we treated human LX2 HSC cells with TGFβ to activate fibrotic pathways, and FOXS1 …

Β2-Glycoprotein I Promotes The Clearance Of Circulating Mitochondria, Swapan Kumar Dasgupta, Jahnavi Gollamudi, Stefanie Rivera, Ross A Poche, Rolando E Rumbaut, Perumal Thiagarajan

Faculty, Staff and Students Publications

β2-glycoprotein I (β2-Gp1) is a cardiolipin-binding plasma glycoprotein. It is evolutionarily conserved from invertebrates, and cardiolipin-bound β2-Gp1 is a major target of antiphospholipid antibodies seen in autoimmune disorders. Cardiolipin is almost exclusively present in mitochondria, and mitochondria are present in circulating blood. We show that β2-Gp1 binds to cell-free mitochondria (CFM) in the circulation and promotes its phagocytosis by macrophages at physiological plasma concentrations. Exogenous CFM had a short circulation time of less than 10 minutes in mice. Following infusion of CFM, β2-Gp1-deficient mice had significantly higher levels of transfused mitochondria at 5 minutes (9.9 ± 6.4 pg/ml versus 4.0 …

Ibrutinib-Associated Cutaneous Mucormycosis Due To An Apophysomyces Species: Report Of A Case And Review Of The Literature, Trung Minh Nguyen, Eva Amenta, Lynne Chapman, Sarvari Yellapragada, Bhuvaneswari Krishnan, Jonathan Lim, Richard J Hamill

Faculty, Staff and Students Publications

The use of ibrutinib, a Bruton tyrosine kinase inhibitor, has been associated with invasive fungal infections (IFIs). We describe a case of Apophysomyces infection associated with long-term use of ibrutinib for the treatment of chronic lymphocytic leukemia as well as perform a literature review of Mucormycosis infections in patients on ibrutinib. Our review found that the onset of IFI can occur within months to years of starting tyrosine kinase inhibitors. These reports provide a more complete picture of the risk of IFI while patients are on ibrutinib. Our case also demonstrates the utility of molecular techniques in the diagnosis of …

The Great Masquerade: Not All Coronary Artery Stenosis Are Created Equal, Prasanti A Kotta, Ajit K Koduri, Jeffrey Berman, Veronica V Rosen, Waleed T Kayani

Faculty, Staff and Students Publications

We present the case of a 60-year-old male, with active smoking and cocaine use disorder, who reported progressive chest pain. Various anatomical and functional cardiac imaging, performed to further evaluate chest pain etiology, revealed changing severity and distribution of left main artery (LMA) stenosis, raising suspicion for vasospasm. Intracoronary nitroglycerin relieved the vasospasm, with resolution of the LMA pseudostenosis. A diagnosis of vasospastic angina (VA) led to starting appropriate medical therapy with lifestyle modification counselling. This case highlights VA, a frequently underdiagnosed etiology of angina pectoris. We discuss when to suspect VA, its appropriate work-up, and management.

Pre-Left Ventricular Assist Device Endoscopic Evaluation Does Not Reduce The Risk Of Later Gastrointestinal Bleeding: A Multicenter Study, Jiahao Peng, Samanthika Devalaraju, Mohamed Azab, William T Cates, Molly Stone, Jonathan Reichstein, Sneha Shaha, Subhasis Chatterjee, Andrew B Civitello, Mourad H Senussi, B Joseph Elmunzer, Michael Volk, Wasseem Skef

Faculty, Staff and Students Publications

BACKGROUND: Gastrointestinal bleeding (GIB) is a common complication after placement of a left ventricular assist device (LVAD). Some institutions attempt to mitigate post-LVAD GIB using preoperative endoscopy. Our study evaluated whether preoperative endoscopy was associated with a lower risk of post-LVAD GIB.

METHODS: This was a multicenter cohort study of patients who underwent LVAD insertion from 2010-2019 at 3 academic sites. A total of 398 study participants were categorized based on whether they underwent preoperative endoscopy or not. The follow-up period was 1 year and the primary outcome was GIB. Secondary outcomes were severe bleeding and intraprocedural complications.

RESULTS: A …

Risk Factors, Incidence, And Outcomes Associated With Clinically Significant Airway Ischemia, Gloria Li, Zejian Liu, Marcelo Salan-Gomez, Emma Keeney, Ethan D'Silva, Babith Mankidy, Andres Leon, Aladdein Mattar, Abdusallam Elsennousi, Jennalee Coster, Anupam Kumar, Bruno Rodrigues, Meng Li, Alexis Shafii, Puneet Garcha, Gabriel Loor

Faculty, Staff and Students Publications

Airway complications following lung transplantation remain an important cause of morbidity and mortality. We aimed to identify the incidence, risk factors and outcomes associated with clinically significant airway ischemia (CSAI) in our center. We reviewed 217 lung transplants (386 airway anastomoses) performed at our institution between February 2016 and December 2020. Airway images were graded using the 2018 ISHLT grading guidelines modified slightly for retrospective analysis. Airways were considered to have CSAI if they developed ischemia severity >B2, stenosis >50%, and/or any degree of dehiscence within 6-months of transplant. Regression analyses were used to evaluate outcomes and risk factors for …

Using Noninvasive Clinical Parameters To Predict Mortality And Morbidity After Cardiac Interventions In Patients With Cirrhosis: A Systematic Review, Christo Mathew, Ankur Patel, George Cholankeril, Avegail Flores, Ruben Hernaez

Faculty, Staff and Students Publications

BACKGROUND: Cardiovascular disease commonly affects advanced liver disease patients. They undergo cardiac interventions to improve cardiac outcomes. Cirrhosis increases complication risk, including bleeding, renal and respiratory failure, and further decompensation, including death, posing a clinical dilemma to proceduralists. Predicting outcomes is crucial in managing patients with cirrhosis. Our aim was to systematically review clinical parameters to assess the mortality and complication risk in patients with cirrhosis undergoing cardiac interventions.

METHODS: We searched cirrhosis and cardiovascular intervention terminology in PubMed and Excerpta Medica Database (EMBASE) from inception to January 8, 2023. We included studies reporting clinical scores (e.g. Model for End-stage …

Klebsiella Pneumoniae Carbapenemase Variant 44 Acquires Ceftazidime-Avibactam Resistance By Altering The Conformation Of Active-Site Loops, Zhizeng Sun, Hanfeng Lin, Liya Hu, Neetu Neetu, Banumathi Sankaran, Jin Wang, B V Venkataram Prasad, Timothy Palzkill

Faculty, Staff and Students Publications

Klebsiella pneumoniae carbapenemase 2 (KPC-2) is an important source of drug resistance as it can hydrolyze and inactivate virtually all β-lactam antibiotics. KPC-2 is potently inhibited by avibactam via formation of a reversible carbamyl linkage of the inhibitor with the catalytic serine of the enzyme. However, the use of avibactam in combination with ceftazidime (CAZ-AVI) has led to the emergence of CAZ-AVI-resistant variants of KPC-2 in clinical settings. One such variant, KPC-44, bears a 15 amino acid duplication in one of the active-site loops (270-loop). Here, we show that the KPC-44 variant exhibits higher catalytic efficiency in hydrolyzing ceftazidime, lower …