Autoimmune Encephalitis Presenting with Acute Excited Catatonia in a 40-Year-Old Male Patient with Covid-19

Acute malignant catatonia with autonomic instability developed in a previously healthy man with PCR-verified SARS-CoV-2. CT and MRI were normal, EEG showed slowing and cerebrospinal fluid showed a subtle indication of inflammation. There were no signs of pathology in other organs. 18F-FDG-PET conveyed high bilateral uptake in the striatum. While commercial tests were negative, immunohistochemical staining of mouse brain revealed anti-neuronal IgG antibodies against neuronal targets in the hippocampus, thalamus, striatum and cortex. Early treatment with plasmapheresis and corticosteroid reversed disease progression and may have prevented large-scale neurological damage. We are not aware of other types of encephalitis with such distinct pyramidal tract symptoms and raise the possibility that this may be a novel form of autoimmune encephalitis induced by infection with SARS-CoV-2.

Making waves in a photoactive polymer film.

Oscillating materials that adapt their shapes in response to external stimuli are of interest for emerging applications in medicine and robotics. For example, liquid-crystal networks can be programmed to undergo stimulus-induced deformations in various geometries, including in response to light. Azobenzene molecules are often incorporated into liquid-crystal polymer films to make them photoresponsive; however, in most cases only the bending responses of these films have been studied, and relaxation after photo-isomerization is rather slow. Modifying the core or adding substituents to the azobenzene moiety can lead to marked changes in photophysical and photochemical properties, providing an opportunity to circumvent the use of a complex set-up that involves multiple light sources, lenses or mirrors. Here, by incorporating azobenzene derivatives with fast cis-to-trans thermal relaxation into liquid-crystal networks, we generate photoactive polymer films that exhibit continuous, directional, macroscopic mechanical waves under constant light illumination, with a feedback loop that is driven by self-shadowing. We explain the mechanism of wave generation using a theoretical model and numerical simulations, which show good qualitative agreement with our experiments. We also demonstrate the potential application of our photoactive films in light-driven locomotion and self-cleaning surfaces, and anticipate further applications in fields such as photomechanical energy harvesting and miniaturized transport.