Scholars@Duke
Samuel Jarrod Francis

Samuel Jarrod Francis

Assistant Professor of Emergency Medicine
Emergency Medicine

Selected Publications

Targeting PIEZO1-TMEM16F Coupling to Mitigate Sickle Cell Disease Complications.

Journal Article Am J Hematol · December 2025 A deeper understanding of sickle cell disease (SCD) pathophysiology is critical for identifying novel therapeutic targets. A hallmark of SCD is abnormal phosphatidylserine (PS) exposure on sickle red blood cells (RBCs), which contributes to anemia, thrombo ... Full text Open Access Link to item Cite

An Aptamer-Based EXACT Anticoagulant as a Sustainable, Animal-Free Alternative to Unfractionated Heparin.

Journal Article Adv Sci (Weinh) · October 6, 2025 Unfractionated heparin (UFH), designated as an essential medicine by the World Health Organization (WHO), is indispensable in cardiac surgery and various clinical applications. However, its production depends on the farming of over a billion large animals ... Full text Link to item Cite

Complement activation as a biomarker for platelet-activating antibodies in heparin-induced thrombocytopenia.

Journal Article J Thromb Haemost · March 2025 BACKGROUND: Immunoglobulin G antibodies (Abs) to platelet factor 4 (PF4) complexed to heparin (PF4/H) commonly occur after H exposure but cause life-threatening complications of H-induced thrombocytopenia (HIT) in only a few patients. Presently, only plate ... Full text Link to item Cite

Oral varespladib for the treatment of snakebite envenoming in India and the USA (BRAVO): a phase II randomised clinical trial.

Journal Article BMJ Glob Health · October 22, 2024 INTRODUCTION: Snakebite envenoming (SBE) results in over 500 000 deaths or disabling injuries annually. Varespladib methyl, an oral inhibitor of secretory phospholipase A2, is a nearly ubiquitous component of snake venoms. We conducted a phase II clinical ... Full text Open Access Link to item Cite

Platelet and red cell responses to three North American pit vipers.

Journal Article Toxicon · August 28, 2024 We investigated the hemotoxic effects of three North American pit vipers in healthy human donor blood. Using experiments focusing on platelet and red blood cell activity, we found differential effects of these venoms on these cellular components. Platelet ... Full text Link to item Cite

Development and Validation of a Natural Language Processing Model to Identify Low-Risk Pulmonary Embolism in Real Time to Facilitate Safe Outpatient Management.

Journal Article Ann Emerg Med · August 2024 STUDY OBJECTIVE: This study aimed to (1) develop and validate a natural language processing model to identify the presence of pulmonary embolism (PE) based on real-time radiology reports and (2) identify low-risk PE patients based on previously validated r ... Full text Link to item Cite

Aptameric hirudins as selective and reversible EXosite-ACTive site (EXACT) inhibitors.

Journal Article Nat Commun · May 10, 2024 Potent and selective inhibition of the structurally homologous proteases of coagulation poses challenges for drug development. Hematophagous organisms frequently accomplish this by fashioning peptide inhibitors combining exosite and active site binding mot ... Full text Link to item Cite

Deciphering and disrupting PIEZO1-TMEM16F interplay in hereditary xerocytosis.

Journal Article Blood · January 25, 2024 Cell-surface exposure of phosphatidylserine (PS) is essential for phagocytic clearance and blood clotting. Although a calcium-activated phospholipid scramblase (CaPLSase) has long been proposed to mediate PS exposure in red blood cells (RBCs), its identity ... Full text Link to item Cite

Clot Imaging Using Photostable Nanodiamond.

Journal Article Nanomaterials (Basel) · March 7, 2023 While thrombosis is the leading cause of morbidity and mortality in the United States, an understanding of its triggers, progression, and response to anticoagulant therapy is lacking. Intravital fluorescence microscopy has advanced the study of thrombus fo ... Full text Link to item Cite

Minimal role for the alternative pathway in complement activation by HIT immune complexes.

Journal Article J Thromb Haemost · November 2022 BACKGROUND: Anti-platelet factor 4 (PF4)/heparin immune complexes that cause heparin-induced thrombocytopenia (HIT) activate complement via the classical pathway. Previous studies have shown that the alternative pathway of complement substantially amplifie ... Full text Link to item Cite

Virologic Efficacy of Casirivimab and Imdevimab COVID-19 Antibody Combination in Outpatients With SARS-CoV-2 Infection: A Phase 2 Dose-Ranging Randomized Clinical Trial.

Journal Article JAMA Netw Open · August 1, 2022 IMPORTANCE: The monoclonal antibody combination of casirivimab and imdevimab reduced viral load, hospitalization, or death when administered as a 1200-mg or greater intravenous (IV) dose in a phase 3 COVID-19 outpatient study. Subcutaneous (SC) and/or lowe ... Full text Link to item Cite

Sex-related differences in D-dimer levels for venous thromboembolism screening.

Journal Article Acad Emerg Med · August 2021 BACKGROUND: D-dimer is generally considered positive above 0.5 mg/L irrespective of sex. However, women have been shown to be more likely to have a positive D-dimer after controlling for other factors. Thus, differences may exist between males and females ... Full text Link to item Cite

Current Controversies in Caring for the Critically Ill Pulmonary Embolism Patient.

Journal Article Emerg Med Clin North Am · November 2020 Emergency physicians must be prepared to rapidly diagnose and resuscitate patients with pulmonary embolism (PE). Certain aspects of PE resuscitation run counter to typical approaches. A specific understanding of the pathophysiology of PE is required to avo ... Full text Link to item Cite

Pediatric patient with a rash.

Journal Article J Am Coll Emerg Physicians Open · August 2020 Full text Link to item Cite

D-dimer levels in VTE patients with distal and proximal clots.

Journal Article Am J Emerg Med · January 2019 OBJECTIVES: There is growing evidence that venous thromboembolism (VTE) patients with distal clots (distal calf deep vein thrombosis [DVT] and sub-segmental pulmonary embolism [PE]) may not routinely benefit from anticoagulation. We compared the D-dimer le ... Full text Link to item Cite

Multicenter Evaluation of the YEARS Criteria in Emergency Department Patients Evaluated for Pulmonary Embolism.

Journal Article Acad Emerg Med · September 2018 BACKGROUND: It may be possible to safely rule out pulmonary embolism (PE) in patients with low pretest probability (PTP) using a higher than standard D-dimer threshold. The YEARS criteria, which include three questions from the Wells PE score to identify l ... Full text Link to item Cite

Emergency Department Discharge of Pulmonary Embolus Patients.

Journal Article Acad Emerg Med · September 2018 BACKGROUND: Hospitalization for low-risk pulmonary embolism (PE) is common, expensive, and of questionable benefit. OBJECTIVE: The objective was to determine if low-risk PE patients discharged from the emergency department (ED) on rivaroxaban require fewer ... Full text Link to item Cite

International, multicenter evaluation of a new D-dimer assay for the exclusion of venous thromboembolism using standard and age-adjusted cut-offs.

Journal Article Thromb Res · June 2018 INTRODUCTION: We sought to determine the test characteristics of an automated INNOVANCE D-dimer assay for the exclusion of pulmonary embolism (PE) and deep venous thrombosis (DVT) in emergency department (ED) patients using standard and age-adjusted cut-of ... Full text Open Access Link to item Cite

Non-invasive vascular laboratory - Who needs it?

Journal Article Nova Scotia Medical Bulletin · January 1, 1986 Cite