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Samuel Jarrod Francis

Assistant Professor of Emergency Medicine
Emergency Medicine

Selected Publications


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

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

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