ABSTRACT
Emerging novel human contagious viruses and pathogens put humans at risk of hospitalization and possibly death due to the unavailability of vaccines and drugs which may take years to develop. Coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was classified as a pandemic by theWorld Health Organization and has caused over 550,000 deaths worldwide as of July 2020. Accurate and scalable point-of-care devices would increase screening, diagnosis, and monitoringof COVID-19 patients. Here, we demonstrate rapid label-free electrochemical detection of SARS-CoV-2 antibodies using a commercially available impedance sensing platform. A 16-well plate containing sensing electrodes was pre-coated with receptor binding domain (RBD) of SARS-CoV-2 spike protein, and subsequently tested with samples of anti-SARS-CoV-2 monoclonal antibody CR3022 (0.1 g/ml, 1.0 g/ml, 10 g/ml). Subsequent blinded testing was performed on six serum specimens taken from COVID-19 and non-COVID-19 patients (1:100 dilution factor). The platformwas able to differentiate spikes in impedance measurements from a negative control (1~ milk solution) for all CR3022 samples. Further, successful differentiation and detection of all positive clinical samples from negative control was achieved. Measured impedance values were consistent when compared to standard ELISA test results showing a strong correlation between them (R2 = 0:9). Detection occurs in less than five minutes and the well-based platform provides a simplified and familiar testing interface that can be readily adaptable for use in clinical settings.
ABSTRACT
Ectopic extramedullary hematopoiesis (EMH), defined as the formation of blood cells outside the bone marrow, usually occurs in a scenario of chronic anemia when, even after conversion of the bony yellow marrow to red marrow, the body is still unable to meet the demand for red blood cells. Ectopic extramedullary hematopoiesis most commonly occurs in the liver and spleen but may, in fact, occur almost anywhere in the body. Although previous reports have documented EMH presenting as paraspinal masses, such lesions have almost always been associated with a predisposing hematological disorder such as hemolytic anemia, myelofibrosis or myelodysplastic syndromes, thalassemia, polycythemia vera, leukemia, or lymphoma. The authors of this report describe the first reported instance of EMH in a patient presenting with a symptomatic epidural and paraspinal cervical lesion arising from the posterior spinal elements and no known predisposing hematological disease. Initial radiographs revealed a bony lesion arising posteriorly from the C2-3 laminae and spinous processes. Subsequent imaging suggested the diagnosis, which was confirmed by CT-guided biopsy, peripheral blood smears, and bone marrow aspirate. Despite epidural compression and slight displacement of the cervical cord and thecal sac, the patient's symptoms were limited to pain and diminished cervical range of motion. Therefore, surgery was deferred in favor of nonsurgical therapy. Several alternative modalities for the treatment of EMH have been suggested in the literature, including cytotoxic agents and radiotherapy. The authors opted for an approach utilizing directed low-dose radiotherapy of a total of 25 Gy divided in 2.5-Gy fractions. At the 3-month follow-up, the patient continued to be asymptomatic, and MRI demonstrated a significant reduction in the dimensions of the lesion. Extramedullary hematopoiesis with spinal cord compression in the absence of a preexisting hematological disorder has not been described in the context of clinical neurosurgical practice. Recognizing that EMH may present as an epidural or paraspinal lesion is important since chemotherapy and radiotherapy are effective therapeutic options in the majority of patients who suffer few if any symptoms. Extensive evaluation for underlying hematological disorders is necessary before undertaking directed therapy. Inadvertent resection of these highly vascularized masses may risk catastrophic intraoperative hemorrhage with no proven benefit as compared with medical treatment, which usually provides excellent long-term outcomes.
