SIRT1 coordinates transcriptional regulation of neural activity and modulates depression-like behaviors in the nucleus accumbens.

BACKGROUND: Major depression and anxiety disorder are significant causes of disability and socio-economic burden. Despite the prevalence and considerable impact of these affective disorders, their pathophysiology remains elusive. Thus, there is an urgent need to develop novel therapeutics for these conditions. We evaluated the role of SIRT1 in regulating dysfunctional processes of reward by using chronic social defeat stress (CSDS) to induce depression- and anxiety-like behaviors. CSDS induces physiological and behavioral changes that recapitulate depression-like symptomatology and alters gene expression programs in the nucleus accumbens, yet cell type-specific changes in this critical structure remain largely unknown. METHODS: We examined transcriptional profiles of D1-MSNs lacking deacetylase activity of SIRT1 by RNA sequencing (RNA-Seq) in a cell-type specific manner using the RiboTag line of mice. We analyzed differentially expressed genes using gene ontology tools including SynGO and EnrichR, and further demonstrated functional changes in D1-MSN specific SIRT1-KO mice using electrophysiological and behavioral measurements. RESULTS: RNAseq revealed altered transcriptional profiles of D1-MSNs lacking functional SIRT1 and showed specific changes in synaptic genes including glutamatergic and GABAergic receptors in D1-MSNs. These molecular changes may be associated with decreased excitatory and increased inhibitory neural activity in Sirt1-KO D1-MSNs, accompanied by morphological changes. Moreover, the D1-MSN-specific Sirt1-KO mice exhibited pro-resilient changes in anxiety- and depression-like behaviors. CONCLUSIONS: SIRT1 coordinates excitatory and inhibitory synaptic genes to regulate GABAergic output tone of D1-MSNs. These findings reveal a novel signaling pathway that has the potential for the development of innovative treatments for affective disorders.

Disproportionate Rates of COVID-19 Among Black Canadian Communities: Lessons from a Cross-Sectional Study in the First Year of the Pandemic.

BACKGROUND: Racialized communities, including Black Canadians, have disproportionately higher COVID-19 cases. We examined the extent to which SARS-CoV-2 infection has affected the Black Canadian community and the factors associated with the infection. METHODS: We conducted a cross-sectional survey in an area of Ontario (northwest Toronto/Peel Region) with a high proportion of Black residents along with 2 areas that have lower proportions of Black residents (Oakville and London, Ontario). SARS-CoV-2 IgG antibodies were determined using the EUROIMMUN assay. The study was conducted between August 15, 2020, and December 15, 2020. RESULTS: Among 387 evaluable subjects, the majority, 273 (70.5%), were enrolled from northwest Toronto and adjoining suburban areas of Peel, Ontario. The seropositivity values for Oakville and London were comparable (3.3% (2/60; 95% CI 0.4-11.5) and 3.9% (2/51; 95% CI 0.5-13.5), respectively). Relative to these areas, the seropositivity was higher for the northwest Toronto/Peel area at 12.1% (33/273), relative risk (RR) 3.35 (1.22-9.25). Persons 19 years of age or less had the highest seropositivity (10/50; 20.0%, 95% CI 10.3-33.7%), RR 2.27 (1.23-3.59). There was a trend for an interaction effect between race and location of residence as this relates to the relative risk of seropositivity. INTERPRETATION: During the early phases of the pandemic, the seropositivity within a COVID-19 high-prevalence zone was threefold greater than lower prevalence areas of Ontario. Black individuals were among those with the highest seroprevalence of SARS-CoV-2.

Paper-Based Vertical Flow Immunoassay for the Point-of-Care Multiplex Detection of Radiation Dosimetry Genes.

In a nuclear or radiological incident, first responders must quickly and accurately measure radiation exposure among civilians as medical countermeasures are radiation dose-dependent and time-sensitive. Although several approaches have been explored to measure absorbed radiation dose, there is an important need to develop point-of-care (POC) bioassay devices that can be used immediately to triage thousands of individuals potentially exposed to radiation. Here we present a proof-of-concept study showing the use of a paper-based vertical flow immunoassay (VFI) to detect radiation dosimetry genes. Using labeled primers during amplification and a multiplex membrane, our results showed that the nucleic acid VFI can simultaneously detect two biodosimetry genes, CDKN1A and DDB2, as well as one housekeeping gene MRPS5. The assay demonstrated good linearity and precision with an inter- and intra-assay coefficient of variance <20% and <10%, respectively. Moreover, the assay showed its ability to discriminate non-irradiated controls (0 Gy) from irradiated samples (1 + 2 Gy) with an overall sensitivity of 62.5% and specificity of 100% (AUC = 0.8672, 95% CI: 0.723-1.000; p = 0.004). Interestingly, the gene combination also showed a dose-dependent response for 0, 1, and 2 Gy, similar to data obtained by real-time PCR benchmark. These preliminary results suggest that a VFI platform can be used to detect simultaneously multiple genes that can be then quantified, thus offering a new approach for a POC biodosimetry assay that could be rapidly deployed on-site to test a large population and help triage and medical management after radiological event.

Point-of-care vertical flow immunoassay system for ultra-sensitive multiplex biothreat-agent detection in biological fluids.

This paper presents simple, fast, and sensitive detection of multiple biothreat agents by paper-based vertical flow colorimetric sandwich immunoassay for detection of Yersinia pestis (LcrV and F1) and Francisella tularensis (lipopolysaccharide; LPS) antigens using a vertical flow immunoassay (VFI) prototype with portable syringe pump and a new membrane holder. The capture antibody (cAb) printing onto nitrocellulose membrane and gold-labelled detection antibody (dAb) were optimized to enhance the assay sensitivity and specificity. Even though the paper pore size was relaxed from previous 0.1 µm to the current 0.45 µm for serum samples, detection limits as low as 0.050 ng/mL for LcrV and F1, and 0.100 ng/mL for FtLPS have been achieved in buffer and similarly in diluted serum (with LcrV and F1 LODs remained the same and LPS LOD reduced to 0.250 ng/mL). These were 40, 80, and 50X (20X for LPS in serum) better than those from lateral flow configuration. Furthermore, the comparison of multiplex format demonstrated low cross-reactivity and equal sensitivity to that of the singleplex assay. The optimized VFI platform thus provides a portable and rapid on-site monitoring system for multiplex biothreat detection with the potential for high sensitivity, specificity, reproducibility, and multiplexing capability, supporting its utility in remote and resource-limited settings.

Optimization of an Antibody Microarray Printing Process Using a Designed Experiment.

Antibody microarrays have proven useful in immunoassay-based point-of-care diagnostics for infectious diseases. Noncontact piezoelectric inkjet printing has advantages to print antibody microarrays on nitrocellulose substrates for this application due to its compatibility with sensitive solutions and substrates, simple droplet control, and potential for high-capacity printing. However, there remain real-world challenges in printing such microarrays, which motivated this study. The effects of three concentrations of capture antibody (cAb) reagents and nozzle hydrostatic pressures were chosen to investigate three responses: the number of printed membrane disks, dispensing performance, and microarray quality. Printing conditions were found to be most ideal with 5 mg/mL cAb and a nozzle hydrostatic pressure near zero, which produced 130 membrane disks in a single print versus the 10 membrane disks per print before optimization. These results serve to inform efficient printing of antibody microarrays on nitrocellulose membranes for rapid immunoassay-based detection of infectious diseases and beyond.

Shisa6 mediates cell-type specific regulation of depression in the nucleus accumbens.

Depression is the leading cause of disability and produces enormous health and economic burdens. Current treatment approaches for depression are largely ineffective and leave more than 50% of patients symptomatic, mainly because of non-selective and broad action of antidepressants. Thus, there is an urgent need to design and develop novel therapeutics to treat depression. Given the heterogeneity and complexity of the brain, identification of molecular mechanisms within specific cell-types responsible for producing depression-like behaviors will advance development of therapies. In the reward circuitry, the nucleus accumbens (NAc) is a key brain region of depression pathophysiology, possibly based on differential activity of D1- or D2- medium spiny neurons (MSNs). Here we report a circuit- and cell-type specific molecular target for depression, Shisa6, recently defined as an AMPAR component, which is increased only in D1-MSNs in the NAc of susceptible mice. Using the Ribotag approach, we dissected the transcriptional profile of D1- and D2-MSNs by RNA sequencing following a mouse model of depression, chronic social defeat stress (CSDS). Bioinformatic analyses identified cell-type specific genes that may contribute to the pathogenesis of depression, including Shisa6. We found selective optogenetic activation of the ventral tegmental area (VTA) to NAc circuit increases Shisa6 expression in D1-MSNs. Shisa6 is specifically located in excitatory synapses of D1-MSNs and increases excitability of neurons, which promotes anxiety- and depression-like behaviors in mice. Cell-type and circuit-specific action of Shisa6, which directly modulates excitatory synapses that convey aversive information, identifies the protein as a potential rapid-antidepressant target for aberrant circuit function in depression.

Examining patterns in medication documentation of trade and generic names in an academic family practice training centre.

BACKGROUND: Studies in the United States have shown that physicians commonly use brand names when documenting medications in an outpatient setting. However, the prevalence of prescribing and documenting brand name medication has not been assessed in a clinical teaching environment. The purpose of this study was to describe the use of generic versus brand names for a select number of pharmaceutical products in clinical documentation in a large, urban academic family practice centre. METHODS: A retrospective chart review of the electronic medical records of the St. Michael's Hospital Academic Family Health Team (SMHAFHT). Data for twenty commonly prescribed medications were collected from the Cumulative Patient Profile as of August 1, 2014. Each medication name was classified as generic or trade. Associations between documentation patterns and physician characteristics were assessed. RESULTS: Among 9763 patients prescribed any of the twenty medications of interest, 45% of patient charts contained trade nomenclature exclusively. 32% of charts contained only generic nomenclature, and 23% contained a mix of generic and trade nomenclature. There was large variation in use of generic nomenclature amongst physicians, ranging from 19% to 93%. CONCLUSIONS: Trade names in clinical documentation, which likely reflect prescribing habits, continue to be used abundantly in the academic setting. This may become part of the informal curriculum, potentially facilitating undue bias in trainees. Further study is needed to determine characteristics which influence use of generic or trade nomenclature and the impact of this trend on trainees' clinical knowledge and decision-making.

Clinical needs finding: developing the virtual experience-a case study.

We describe an innovative program at the University of California, Davis for students to engage in clinical needs finding. Using a team-based approach, students participated in clinical rotations to observe firsthand the needs of clinicians at the university affiliated medical center. The teams were asked to develop documentary-style videos to capture key experiences that would allow future viewers to use the videos as "virtual" clinical rotations. This was conceived as a strategy to allow students in prohibitively large classes, or students in programs at institutions without associated medical or veterinary school programs, to experience clinical rotations and perform needs assessments. The students' perspectives on the experience as well as instructor analysis of best practices for this type of activity are presented and discussed. We found that the internship experience was valuable to the students participating, by not only introducing the practice of needs finding but also increasing the students' confidence in the practice of engineering design and their ability to work independently. The videos produced were of such high quality that instructors from other institutions have requested copies for instructional use. Virtual clinical rotations through video experiences may provide a reasonable substitute for students who do not have the ability to participate in rotations in person.