Nasopharyngeal versus nasal swabs for detection of SARS-CoV-2: a systematic review.

Nasopharyngeal swabbing (NPS) coupled with RT-PCR is the current gold standard for detecting SARS-CoV-2 infections. However, numerous studies have recently demonstrated the advantages of alternative nasal specimen collection approaches over NPS specifically for COVID-19 diagnosis. The present review was conducted according to PRISMA guidelines and summarises the current literature to give a clear overview of nasal specimen collection methods for SARS-CoV-2 detection. Publications investigating NPS and at least one other form of nasal specimen collection in combination with RT-PCR for viral detection in the context of COVID-19 were assessed. We identified 425 articles and ultimately included 18 studies in this systematic review. The suitable publications evaluated different forms of nasal specimen collection, with anterior nasal swabbing (ANS) and midturbinate swabbing (MTS) being the most frequently examined techniques. The analysed studies report sensitivity and specificity results (67.5-96.2% and 97.9-100.0%, respectively) similar to those achieved via NPS, especially in the early stages of disease or when paired with an oropharyngeal swab. Results from these studies suggest that ANS and MTS are suitable alternatives to NPS for COVID-19 testing. Due to their ease of collection, ANS and MTS collection techniques may facilitate broader testing strategies and allow for economization of medical staff.

Photoperiod regulates genes encoding melanocortin 3 and serotonin receptors and secretogranins in the dorsomedial posterior arcuate of the Siberian hamster.

The mechanism(s) involved in the regulation of the seasonal-appropriate body weight of the Siberian hamster are currently unknown. We have identified photoperiodically regulated genes including VGF in a sub-region of the arcuate nucleus termed the dorsomedial posterior arcuate (dmpARC). Gene expression changes in this nucleus so far account for a significant number of those reported as photoperiodically regulated and are therefore likely to contribute to seasonal physiological responses of the hamsters. The present study aimed to identify additional genes expressed in the dmpARC regulated by photoperiod that could be involved in regulating the activity of this nucleus with respect to seasonal physiology of the Siberian hamster. Using laser capture microdissection coupled with a microarray analysis and a candidate gene approach, we have identified several photoperiodically regulated genes in the dmpARC that are known to have roles in secretory and intracellular signalling pathways. These include secretogranin (sg) III and SgVI (secretory pathway), melanocortin 3 receptor (MC3-R) and serotonin (5-HT) receptors 2A and 7 (signalling pathway), all of which increase in expression under a short photoperiod. The spatial relationship between receptor signalling and potential secretory pathways was investigated by dual in situ hybridisation, which revealed that 5-HT2A and 5-HT7 receptors are expressed in neurones expressing VGF mRNA and that a sub-population (approximately 40%) of these neurones express MC3-R. These gene expression changes in dmpARC neurones may reflect the functional requirement of these neurones for seasonal physiological responses of the hamster.