Surveillance of Vermont wildlife in 2021-2022 reveals no detected SARS-CoV-2 viral RNA.

Previous studies have documented natural infections of SARS-CoV-2 in various domestic and wild animals. More recently, studies have been published noting the susceptibility of members of the Cervidae family, and infections in both wild and captive cervid populations. In this study, we investigated the presence of SARS-CoV-2 in mammalian wildlife within the state of Vermont. 739 nasal or throat samples were collected from wildlife throughout the state during the 2021 and 2022 harvest season. Data was collected from red and gray foxes (Vulpes vulples and Urocyon cineroargentus, respectively), fishers (Martes pennati), river otters (Lutra canadensis), coyotes (Canis lantrans), bobcats (Lynx rufus rufus), black bears (Ursus americanus), and white-tailed deer (Odocoileus virginianus). Samples were tested for the presence of SARS-CoV-2 via quantitative RT-qPCR using the CDC N1/N2 primer set and/or the WHO-E gene primer set. Surprisingly, we initially detected a number of N1 and/or N2 positive samples with high cycle threshold values, though after conducting environmental swabbing of the laboratory and verifying with a second independent primer set (WHO-E) and PCR without reverse transcriptase, we showed that these were false positives due to plasmid contamination from a construct expressing the N gene in the general laboratory environment. Our final results indicate that no sampled wildlife were positive for SARS-CoV-2 RNA, and highlight the importance of physically separate locations for the processing of samples for surveillance and experiments that require the use of plasmid DNA containing the target RNA sequence. These negative findings are surprising, given that most published North America studies have found SARS-CoV-2 within their deer populations. The absence of SARS-CoV-2 RNA in populations sampled here may provide insights in to the various environmental and anthropogenic factors that reduce spillover and spread in North American's wildlife populations.

Surveillance of Vermont wildlife in 2021-2022 reveals no detected SARS-CoV-2 viral RNA.

Previous studies have documented natural infections of SARS-CoV-2 in various domestic and wild animals. More recently, studies have been published noting the susceptibility of members of the Cervidae family, and infections in both wild and captive cervid populations. In this study, we investigated the presence of SARS-CoV-2 in mammalian wildlife within the state of Vermont. 739 nasal or throat samples were collected from wildlife throughout the state during the 2021 and 2022 harvest season. Data was collected from red and gray foxes ( Vulpes vulples and Urocyon cineroargentus , respectively), fishers ( Martes pennati ), river otters ( Lutra canadensis ), coyotes ( Canis lantrans ), bobcats ( Lynx rufus rufus ), black bears ( Ursus americanus ), and white-tailed deer ( Odocoileus virginianus ). Samples were tested for the presence of SARS-CoV-2 via quantitative RT-qPCR using the CDC N1/N2 primer set and/or the WHO-E gene primer set. Our results indicate that no sampled wildlife were positive for SARS-CoV-2. This finding is surprising, given that most published North America studies have found SARS-CoV-2 within their deer populations. The absence of SARS-CoV-2 RNA in populations sampled here may provide insights in to the various environmental and anthropogenic factors that reduce spillover and spread in North American's wildlife populations.

Men Are at Higher Risk of Screening Positive for Vascular Cognitive Impairment Compared to Women after Stroke and Transient Ischemic Attack.

While women have greater incidence of dementia, men have higher prevalence of vascular risk factors. This study examined sex differences in risk of screening positive for cognitive impairment after stroke. Ischemic stroke/TIA patients (N = 5969) participated in this prospective, multi-centered study, which screened for cognitive impairment using a validated brief screen. Men showed a higher risk of screening positive for cognitive impairment after adjusting for age, education, stroke severity, and vascular risk factors, suggesting that other factors may be contributing to increased risk among men (OR = 1.34, CI 95% [1.16, 1.55], p < 0.001). The effect of sex on cognitive impairment after stroke warrants further attention.

Language discordance as a marker of disparities in cerebrovascular risk and stroke outcomes: A multi-center Canadian study.

Background: Differences in ischemic stroke outcomes occur in those with limited English proficiency. These health disparities might arise when a patient's spoken language is discordant from the primary language utilized by the health system. Language concordance is an understudied concept. We examined whether language concordance is associated with differences in vascular risk or post-stroke functional outcomes, depression, obstructive sleep apnea and cognitive impairment. Methods: This was a multi-center observational cross-sectional cohort study. Patients with ischemic stroke/transient ischemic attack (TIA) were consecutively recruited across eight regional stroke centers in Ontario, Canada (2012 - 2018). Participants were language concordant (LC) if they spoke English as their native language, ESL if they used English as a second language, or language discordant (LD) if non-English speaking and requiring translation. Results: 8156 screened patients. 6,556 met inclusion criteria: 5067 LC, 1207 ESL and 282 LD. Compared to LC patients: (i) ESL had increased odds of diabetes (OR = 1.28, p = 0.002), dyslipidemia (OR = 1.20, p = 0.007), and hypertension (OR = 1.37, p<0.001) (ii) LD speaking patients had an increased odds of having dyslipidemia (OR = 1.35, p = 0.034), hypertension (OR = 1.37, p<0.001), and worse functional outcome (OR = 1.66, p<0.0001). ESL (OR = 1.88, p<0.0001) and LD (OR = 1.71, p<0.0001) patients were more likely to have lower cognitive scores. No associations were noted with obstructive sleep apnea (OSA) or depression. Conclusions: Measuring language concordance in stroke/TIA reveals differences in neurovascular risk and functional outcome among patients with limited proficiency in the primary language of their health system. Lower cognitive scores must be interpreted with caution as they may be influenced by translation and/or greater vascular risk. Language concordance is a simple, readily available marker to identify those at risk of worse functional outcome. Stroke systems and practitioners must now study why these differences exist and devise adaptive care models, treatments and education strategies to mitigate barriers influenced by language discordance.

Post-stroke depression, obstructive sleep apnea, and cognitive impairment: Rationale for, and barriers to, routine screening.

Stroke can cause neurological impairment ranging from mild to severe, but the impact of stroke extends beyond the initial brain injury to include a complex interplay of devastating comorbidities including: post-stroke depression, obstructive sleep apnea, and cognitive impairment ("DOC"). We reviewed the frequency, impact, and treatment options for each DOC condition. We then used the Ottawa Model of Research Use to examine gaps in care, understand the barriers to knowledge translation, identification, and addressing these important post-stroke comorbidities. Each of the DOC conditions is common and result in poorer recovery, greater functional impairment, increased stroke recurrence and mortality, even after accounting for traditional vascular risk factors. Despite the strong relationships between DOC comorbidities and these negative outcomes as well as recommendations for screening based on best practice recommendations from several countries, they are frequently not assessed. Barriers related to the nature of the screening tools (e.g., time consuming in high-volume clinics), practice environment (e.g., lack of human resources or space), as well as potential adopters (e.g., equipoise surrounding the benefits of treatment for these conditions) pose challenges to routine screening implementation. Simple, feasible approaches to routine screening coupled with appropriate, evidence-based treatment protocols are required to better identify and manage depression, obstructive sleep apnea, and cognitive impairment symptoms in stroke prevention clinic patients to reduce the impact of these important post-stroke comorbidities. These tools may in turn facilitate large-scale randomized controlled treatment trials of interventions for DOC conditions that may help to improve cardiovascular outcomes after stroke or TIA.

Ca2+-dependent induction of TRPM2 currents in hippocampal neurons.

TRPM2 is a Ca(2+)-permeable member of the transient receptor potential melastatin family of cation channels whose activation by reactive oxygen/nitrogen species (ROS/RNS) and ADP-ribose (ADPR) is linked to cell death. While these channels are broadly expressed in the CNS, the presence of TRPM2 in neurons remains controversial and more specifically, whether they are expressed in neurons of the hippocampus is an open question. With this in mind, we examined whether functional TRPM2 channels are expressed in this neuronal population. Using a combination of molecular and biochemical approaches, we demonstrated the expression of TRPM2 transcripts and proteins in hippocampal pyramidal neurons. Whole-cell voltage-clamp recordings were subsequently carried out to assess the presence of TRPM2-mediated currents. Application of hydrogen peroxide or peroxynitrite to cultured hippocampal pyramidal neurons activated an inward current that was abolished upon removal of extracellular Ca(2+), a hallmark of TRPM2 activation. When ADPR (300 microM) was included in the patch pipette, a large inward current developed but only when depolarizing voltage ramps were continuously (1/10 s) applied to the membrane. This current exhibited a linear current-voltage relationship and was sensitive to block by TRPM2 antagonists (i.e. clotrimazole, flufenamic acid and N-(p-amylcinnamoyl)anthranilic acid (ACA)). The inductive effect of voltage ramps on the ADPR-dependent current required voltage-dependent Ca(2+) channels (VDCCs) and a rise in [Ca(2+)](i). Consistent with the need for a rise in [Ca(2+)](i), activation of NMDA receptors (NMDARs), which are highly permeable to Ca(2+), was also permissive for current development. Importantly, given the prominent vulnerability of CA1 neurons to free-radical-induced cell death, we confirmed that, with ADPR in the pipette, a brief application of NMDA could evoke a large inward current in CA1 pyramidal neurons from hippocampal slices that was abolished by the removal of extracellular Ca(2+), consistent with TRPM2 activation. Such a current was absent in interneurons of CA1 stratum radiatum. Finally, infection of cultured hippocampal neurons with a TRPM2-specific short hairpin RNA (shRNA(TRPM2)) significantly reduced both the expression of TRPM2 and the amplitude of the ADPR-dependent current. Taken together, these results indicate that hippocampal pyramidal neurons possess functional TRPM2 channels whose activation by ADPR is functionally coupled to VDCCs and NMDARs through a rise in [Ca(2+)](i).

Cell type-specific changes in spontaneous and minimally evoked excitatory synaptic activity in hippocampal CA1 interneurons of kainate-treated rats.

The epileptiform activity in the kainic acid (KA) model of epilepsy arises from complex changes in excitation and inhibition. To assess the involvement of excitatory drive onto inhibitory interneurons in this epileptiform activity, we examined changes in spontaneous and minimally evoked excitatory post-synaptic currents (sEPSCs and eEPSCs) in CA1 interneurons in stratum oriens/alveus (O/A) and stratum radiatum (RAD) in rat hippocampal slices after KA treatment. The frequency and amplitude of sEPSCs and the amplitude of eEPSCs were unchanged in O/A interneurons, but the EPSC kinetics were significantly slower. These changes appear to be due to altered kinetics and voltage-dependent properties of the NMDA component of EPSCs in O/A interneurons. In contrast, sEPSCs and eEPSCs in RAD interneurons did not change after KA treatment. The distinct changes in excitatory synaptic activity in interneurons differentially involved in feedback (O/A) versus feedforward (RAD) inhibition suggest a cell type-specific reorganization of excitatory synapses after KA treatment. These modifications in excitatory input to interneurons could contribute to the maintenance of inhibition of CA1 pyramidal cells after KA treatment, or may also create network conditions favourable to epileptiform activity.

A D2 class dopamine receptor transactivates a receptor tyrosine kinase to inhibit NMDA receptor transmission.

Receptor tyrosine kinases (RTKs) are membrane spanning proteins with intrinsic kinase activity. Although these receptors are known to be involved in proliferation and differentiation of cells, their roles in regulating central synaptic transmission are largely unknown. In CA1 pyramidal neurons, activation of D2 class dopamine receptors depressed excitatory transmission mediated by the NMDA subtype of glutamate receptor. This depression resulted from the quinpirole-induced release of intracellular Ca(2+) and enhanced Ca(2+)-dependent inactivation of NMDA receptors. The dopamine receptor-mediated depression was dependent on the "transactivation" of PDGFRbeta. Therefore, RTK transactivation provides a novel mechanism of communication between dopaminergic and glutamatergic systems and might help to explain how reciprocal changes in these systems could be linked to the deficits in cognition, memory, and attention observed in schizophrenia and attention deficit hyperactivity disorder.