Neuroblastoma‐like schwannoma of the skull base: an enigmatic peripheral nerve sheath tumor variant

Neuroblastoma‐like schwannoma is an extremely rare histological variant of schwannoma, which histologically mimics a malignant small round cell tumor. Only 19 cases have been reported in the literature to date. We report a case of this tumor located at the skull base in a 44‐year‐old woman who presented with symptoms of right‐sided earache and hearing loss. MRI revealed a large, lobulated, extra‐axial mass measuring 8.8 cm × 3.6 cm × 4.2 cm in the floor of the middle and posterior cranial fossa. Microscopic examination revealed a perplexing histopathology with peculiar collagenous rosettes. Differential diagnoses included a broad range of benign and malignant tumors. Typical schwannoma seldom poses a difficulty in diagnosis; however, this unusual variant is a diagnostic challenge which requires an extensive clinico‐radiological correlation and immunohistochemical work‐up. Hence, knowledge of this entity is a must to avoid erroneous diagnosis and inappropriate treatment.     

Follow-up computed tomography scan in post-COVID-19 pneumonia

The coronavirus disease 2019 (COVID-19) global pandemic can be a severe illness that leads to morbidity and mortality. With the increasing number of COVID-19 pneumonia survivors, several long-term changes may persist, including abnormal imaging of lung parenchyma. In addition to the clinical course, it is vital to follow up on pulmonary imaging during the post-infectious period, which is not routinely required in other common pulmonary diagnoses. Computed tomography (CT) scan of the chest is an effective and diagnostic tool for pneumonia which gives an insight into structural abnormalities within the lungs, complications, and possible progression of the disease. Several studies have monitored COVID-19 pneumonia and its complications using serial CT chest imaging from the initial phase of infection, hospitalization, and post-discharge. Nonetheless, long-term follow-up imaging data in post-COVID-19 is still limited. We have summarized the findings utilizing a systematic review of the literature regarding COVID-19 pneumonia imaging, including long-term follow-up.     

The Safety of Ultrasound-Guided Thoracentesis in Patients on Novel Oral Anticoagulants and Clopidogrel: A Single-Center Experience

ObjectiveTo assess the risk of hemorrhagic complications in patients taking novel oral anticoagulants (NOACs) and/or clopidogrel who underwent an ultrasound-guided thoracentesis.Patients and MethodsA retrospective analysis was performed of ultrasound-guided thoracenteses completed at an academic institution between January 1, 2016, and November 14, 2017. All patients who underwent a thoracentesis while actively receiving treatment with an NOAC and/or clopidogrel were included in the study. Primary endpoints are any significant post-procedure bleeding complication; defined as a hemoglobin decrease of greater than 2 g/dL in 48 hours, hemothorax, chest wall hematoma, and bleeding requiring transfusion, surgery, or chest tube placement.ResultsA total of 115 thoracenteses were performed in 103 patients actively taking an NOAC (n=43) and/or clopidogrel (n=69). All patients used either the NOAC or clopidogrel within 24 hours before the procedure and continued using it daily thereafter. There were no bleeding complications.ConclusionThe overall risk of significant hemorrhage in patients taking an NOAC and/or clopidogrel while undergoing ultrasound-guided thoracentesis is very low. Albeit the total number of procedures reviewed may be insufficient to prove definitive safety, it is sufficient to provide a measure of relative risk when assessing benefits of thoracentesis in these patients.     

Smartphone-based kanamycin sensing with ratiometric FRET

Smartphone-based fluorescence detection is a promising avenue for biosensing that can aid on-site analysis. However, quantitative detection with fluorescence in the field has been limited due to challenges with robust excitation and calibration requirements. Here, we show that ratiometric analysis with Förster resonance energy transfer (FRET) between dye pairs on DNA aptamers can enable rapid and sensitive kanamycin detection. Since our detection scheme relies on ligand binding-induced changes in the aptamer tertiary structure, it is limited only by the kinetics of ligand binding to the aptamer. Our FRET-based kanamycin binding aptamer (KBA) sensor displays two linear ranges of 0.05–5 nM (detection limit of 0.18 nM) and 50–900 nM of kanamycin. The aptamer displays high specificity even in the presence of the ‘natural’ background from milk. By immobilizing the aptamer in the flow cell, our KBA sensor design is also suitable for repeated kanamycin detection. Finally, we show that the ratiometric FRET-based analysis can be implemented on a cheap custom-built smartphone setup. This smartphone-based FRET aptamer scheme detects kanamycin in a linear range of 50–500 nM with a limit of detection (LOD) of 28 nM.

FRET aptamer based kanamycin detection enables reusable and smartphone sensing.