Mechanics of Intact Bone Marrow

The current knowledge of bone marrow mechanics is limited to its viscous properties, neglecting the elastic contribution of the extracellular matrix. To get a more complete view of the mechanics of marrow, we characterized intact yellow porcine bone marrow using three different, but complementary techniques: rheology, indentation, and cavitation. Our analysis shows that bone marrow is elastic, and has a large amount of intra- and inter-sample heterogeneity, with an effective Young’s modulus ranging from 0.25-24.7 kPa at physiological temperature. Each testing method was consistent across matched tissue samples, and each provided unique benefits depending on user needs. We recommend bulk rheology to capture the effects of temperature on tissue elasticity and moduli, indentation for quantifying local tissue heterogeneity, and cavitation rheology for mitigating destructive sample preparation. We anticipate the knowledge of bone marrow elastic properties for building in vitro models will elucidate mechanisms involved in disease progression and regenerative medicin

The high risk HPV16 L2 minor capsid protein has multiple transport signals that mediate its nucleocytoplasmic traffic

AbstractIn this study we examined the transport signals contributing to HPV16 L2 nucleocytoplasmic traffic using confocal microscopy analysis of enhanced green fluorescent protein—L2 (EGFP-L2) fusions expressed in HeLa cells. We confirmed that both nuclear localization signals (NLSs), the nNLS (1MRHKRSAKRTKR12) and cNLS (456RKRRKR461), previously characterized in vitro (Darshan et al., 2004), function independently in vivo. We discovered that a middle region rich in arginine residues (296SRRTGIRYSRIGNKQTLRTRS316) functions as a nuclear retention sequence (NRS), as mutagenesis of critical arginine residues within this NRS reduced the fraction of L2 in the nucleus despite the presence of both NLSs. Significantly, the infectivity of HPV16 pseudoviruses containing either RR297AA or RR297EE within the L2 NRS was strongly reduced both in HaCaT cells and in a murine challenge model. Experiments using Ratjadone A nuclear export inhibitor and mutation-localization analysis lead to the discovery of a leucine-rich nuclear export signal (462LPYFFSDVSL) mediating 16L2 nuclear export. These data indicate that HPV16 L2 nucleocytoplasmic traffic is dependent on multiple functional transport signals

HIV Clustering in Mississippi: Spatial Epidemiological Study to Inform Implementation Science in the Deep South

Background: In recent years, more than half of new HIV infections in the United States occur among African Americans in the Southeastern United States. Spatial epidemiological analyses can inform public health responses in the Deep South by identifying HIV hotspots and community-level factors associated with clustering. Objective: The goal of this study was to identify and characterize HIV clusters in Mississippi through analysis of state-level HIV surveillance data. Methods: We used a combination of spatial epidemiology and statistical modeling to identify and characterize HIV hotspots in Mississippi census tracts (n=658) from 2008 to 2014. We conducted spatial analyses of all HIV infections, infections among men who have sex with men (MSM), and infections among African Americans. Multivariable logistic regression analyses identified community-level sociodemographic factors associated with HIV hotspots considering all cases. Results: There were HIV hotspots for the entire population, MSM, and African American MSM identified in the Mississippi Delta region, Southern Mississippi, and in greater Jackson, including surrounding rural counties (P \u3c .05). In multivariable models for all HIV cases, HIV hotspots were significantly more likely to include urban census tracts (adjusted odds ratio [AOR] 2.01, 95% CI 1.20-3.37) and census tracts that had a higher proportion of African Americans (AOR 3.85, 95% CI 2.23-6.65). The HIV hotspots were less likely to include census tracts with residents who had less than a high school education (AOR 0.95, 95% CI 0.92-0.98), census tracts with residents belonging to two or more racial/ethnic groups (AOR 0.46, 95% CI 0.30-0.70), and census tracts that had a higher percentage of the population living below the poverty level (AOR 0.51, 95% CI 0.28-0.92). Conclusions: We used spatial epidemiology and statistical modeling to identify and characterize HIV hotspots for the general population, MSM, and African Americans. HIV clusters concentrated in Jackson and the Mississippi Delta. African American race and urban location were positively associated with clusters, whereas having less than a high school education and having a higher percentage of the population living below the poverty level were negatively associated with clusters. Spatial epidemiological analyses can inform implementation science and public health response strategies, including improved HIV testing, targeted prevention and risk reduction education, and tailored preexposure prophylaxis to address HIV disparities in the South

2017 Research & Innovation Day Program

A one day showcase of applied research, social innovation, scholarship projects and activities.https://first.fanshawec.ca/cri_cripublications/1004/thumbnail.jp

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Inside Insite: The cost-effectiveness of supervised injection facilities

The debate around supervised injection facilities (SIF) rages on more than a decade after the opening of Insite, Canada’s first supervised injection site in Vancouver. Recently, an article published in the journal Addiction reignited the discussion when it made a financial case for introducing facilities in Ottawa and Toronto. The model predicts that the introduction of two SIFs in Ottawa and three in Toronto would be a cost-savings measure to prevent the spread of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) among intravenous drug users (IVDUs). Over 600 total cases of HIV or HCV are projected to be averted in a 20-year period, saving over $40 million in healthcare costs in Toronto and over$30 million in Ottawa. Opponents deny the benefits of safe injection sites despite research conducted on Insite, which suggest that these facilities have tremendous utility and are economically viable. Insite targets and attracts high-risk IVDUs, fosters safer injection habits and prevents transmission of needle-sharing diseases. Insite’s facilities also offer complementary detoxification and rehabilitation services and encourage users to register for these programs. In contrast to arguments made by opponents, Insite has not been found to increase incidental overdoses, neighbourhood crime rates, or public disposal of needles. Given the outcomes of research conducted on Insite, the viability of similar facilities in Ontario should be further explored.&nbsp

Canadian healthcare readiness for public health emergencies

Following the 2003 SARS (Severe Acute Respiratory Syndrome) outbreak in Toronto, there remains a concern that Canada’s healthcare systems are inadequately equipped to respond to a future public health emergency. Public health emergencies, defined as an emergency need for health care services to respond to a disaster, significant or catastrophic event, are economically costly. Effective prevention and responses to future emergencies would prevent economic costs like those from the 2003 SARS outbreak. An analysis from Hawryluck et al. of the SARS response identified major gaps: incomplete infection control, lack of system-wide communications, and no system-wide coordination leading to isolated, inefficient responses. More than a decade later, improvements have been made but there are areas in the infection control protocol that still require changes. More training is required for Emergency Medical Services (EMS) personnel to effectively handle emergency scenes and to improve multiple agency coordination. Local hospitals need to improve their surge capacity, administrative emergency preparedness infrastructure, and personnel training. The creation of the Public Health Agency of Canada (PHAC) in 2004 responded to concerns about the capacity of Canada’s healthcare system to respond effectively to public health threats. At the provincial level, the Emergency Management Branch (EMB) works effectively similar to and in coordination with PHAC. The needs for improvement should question if Canada will be able to handle the next public health emergency that rolls through its door