Post-Vaccination/Post-COVID Immune-Mediated Demyelination of the Brain and Spinal Cord: A Novel Neuroimaging Finding.

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which not only produces respiratory symptoms but is known to involve almost every system, and its neuroinvasive properties have been well demonstrated throughout the pandemic. Also, to combat the pandemic, there was rapid development and induction of various vaccination drives, following which many adverse events following immunization (AEFIs) have been reported, which include neurological complications as well. Method: We present a series of three cases, post vaccination, with and without a history of COVID illness that showed remarkably similar findings on magnetic resonance imaging (MRI). Result: A 38-year-old male presented with complaints of weakness of the bilateral lower limbs with sensory loss and bladder disturbance a day after receiving his first dose of ChadOx1 nCoV-19 (COVISHIELD) vaccine. A 50-year-old male with hypothyroidism characterized by autoimmune thyroiditis and impaired glucose tolerance experienced difficulty in walking 11.5 weeks after being administered with COVID vaccine (COVAXIN). A 38-year-old male presented with subacute onset progressive symmetric quadriparesis 2 months after their first dose of a COVID vaccine. The patient also had sensory ataxia, and his vibration sensation was impaired below C7. All three patients had typical pattern of involvement of the brain and spine on MRI with signal changes in bilateral corticospinal tracts, trigeminal tracts in the brain, and both lateral and posterior columns in the spine. Conclusion: This pattern of brain and spine involvement on MRI is a novel finding and is likely a result of post-vaccination/post-COVID immune-mediated demyelination.

Carbon Dots Conjugated Antibody as an Effective FRET-Based Biosensor for Progesterone Hormone Screening.

In this work, carbon dots (CDs) were synthesized by a one-step hydrothermal method using citric acid and ethylene diamine, and covalently functionalized with antibodies for the sensing of progesterone hormone. The structural and morphological analysis reveals that the synthesized CDs are of average size (diameter 8-10 nm) and the surface functionalities are confirmed by XPS, XRD and FT-IR. Further graphene oxide (GO) is used as a quencher due to the fluorescence resonance energy transfer (FRET) mechanism, whereas the presence of the analyte progesterone turns on the fluorescence because of displacement of GO from the surface of CDs effectively inhibiting FRET efficiency due to the increased distance between donor and acceptor moieties. The linear curve is obtained with different progesterone concentrations with 13.8 nM detection limits (R2 = 0.974). The proposed optical method demonstrated high selectivity performance in the presence of structurally resembling interfering compounds. The PL intensity increased linearly with the increased progesterone concentration range (10-900 nM) under the optimal experimental parameters. The developed level-free immunosensor has emerged as a potential platform for simplified progesterone analysis due to the high selectivity performance and good recovery in different samples of spiked water.