COVID-19 induces CNS cytokine expression and loss of hippocampal neurogenesis.

Infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with acute and postacute cognitive and neuropsychiatric symptoms including impaired memory, concentration, attention, sleep and affect. Mechanisms underlying these brain symptoms remain understudied. Here we report that SARS-CoV-2-infected hamsters exhibit a lack of viral neuroinvasion despite aberrant blood-brain barrier permeability. Hamsters and patients deceased from coronavirus disease 2019 (COVID-19) also exhibit microglial activation and expression of interleukin (IL)-1ß and IL-6, especially within the hippocampus and the medulla oblongata, when compared with non-COVID control hamsters and humans who died from other infections, cardiovascular disease, uraemia or trauma. In the hippocampal dentate gyrus of both COVID-19 hamsters and humans, we observed fewer neuroblasts and immature neurons. Protracted inflammation, blood-brain barrier disruption and microglia activation may result in altered neurotransmission, neurogenesis and neuronal damage, explaining neuropsychiatric presentations of COVID-19. The involvement of the hippocampus may explain learning, memory and executive dysfunctions in COVID-19 patients.

3D-printed neck phantoms with detailed anatomy for ultrasound-guided procedure and device testing.

Objectives: With rapid advances in ultrasound-guided procedures, there is an unmet need for echogenic phantoms with sufficient anatomical details for artificial intelligence and ultrasound-guided device testing. We developed a method for creating neck phantoms for novel otolaryngology-related device testing. To achieve accurate representation of the anatomy, we utilized CT scans and 3D printing technology to create customized agar molds, thus providing high-fidelity yet cost-effective tools. Methods: Based on previous studies, the key components in our neck phantom include the cervical vertebrae, trachea, common carotid arteries, internal jugular veins, thyroid gland, and surrounding soft tissue. Open-source image analysis software were employed to process CT data to generate high fidelity 3D models of the target structures. Resin molds were 3D printed and filled with various agar mixtures to mimic anatomical echogenicity. Results: Following the method proposed, we successfully assembled the neck phantom which provided a detailed representation of the target structures. To evaluate the results, ultrasound data was collected on the phantom and living tissue and analyzed with ImageJ. We were able to demonstrate echogenicity comparable to that of living tissue. Conclusion: The proposed method for building neck phantoms with detailed anatomical features offers a valuable, detailed, low-cost tool for medical training and device testing in otolaryngology, particularly for novel devices that involve artificial intelligence (AI) guidance and robotic-based needle insertion. Additional anatomical refinements and validation studies could further enhance the consistency and accuracy, thus paving the way for future advancements in ultrasound training and research, and ultimately benefiting patient care and safety.