Effects of zooplankton size and concentration and light intensity on the feeding behavior of Atlantic mackerel \u3cem\u3eScomber scombrus\u3c/em\u3e

Atlantic mackerel Scomber scombrus had low clearance rates when fed older stage copepodites of the copepod Calanus finmarchicus at high concentrations and high clearance rates at low concentrations. These rates were consistent with filter feeding at high concentrations and particulate feeding at low concentrations. Intermediate and small copepods presented together at high concentrations were cleared at lower rates than the large C. finmarchicus, suggesting lower filtration efficiencies. Intermediate and small copepods were presented over a range of light intensities (8.2 x 10-8 to 1.6 x 100 µE m-2 s-1). Feeding rate did not change significantly between 1.6 x 100 and 2.0 x 10-6 µE m-2 s-1, but decreased to nearly zero at 8.2 x 10-8 µE m-2 s-1, indicating a light intensity threshold for feeding of about 10-7 µE m-2 s-1. This threshold enables mackerel to feed throughout the night near the ocean surface. Swimming speed decreased to a lesser degree than feeding rate at the lowest light intensity, indicating that the change in filter-feeding rate is only partially due to the change in speed. The school dispersed in both low and high light levels, but spacing between fish did not appear to be related to feeding rate

Data-Driven Decision Support Tool Co-Development with a Primary Health Care Practice Based Learning Network

Background: The Alliance for Healthier Communities is a learning health system that supports Community Health Centres (CHCs) across Ontario, Canada to provide team-based primary health care to people who otherwise experience barriers to care. This case study describes the ongoing process and lessons learned from the first Alliance for Healthier Communities’ Practice Based Learning Network (PBLN) data-driven decision support tool co-development project. Methods: We employ an iterative approach to problem identification and methods development for the decision support tool, moving between discussion sessions and case studies with CHC electronic health record (EHR) data. We summarize our work to date in terms of six stages: population-level descriptive-exploratory study, PBLN team engagement, decision support tool problem selection, sandbox case study 1: individual-level risk predictions, sandbox case study 2: population-level planning predictions, project recap and next steps decision. Results: The population-level study provided an initial point of engagement to consider how clients are (not) represented in EHR data and to inform problem selection and methodological decisions thereafter. We identified three meaningful types of decision support, with initial target application areas: risk prediction/screening, triaging specialized program referrals, and identifying care access needs. Based on feasibility and expected impact, we started with the goal to support earlier identification of mental health decline after diabetes diagnosis. As discussions deepened around clinical use cases associated with example prediction task set ups, the target problem evolved towards supporting the upstream task of organizational planning and advocacy for adequate mental health care service capacity to meet incoming needs. Conclusions: This case study contributes towards a tool to support diabetes and mental health care, as well as lays groundwork for future CHC decision support tool initiatives. We share lessons learned and reflections from our process that other primary health care organizations may use to inform their own co-development initiatives

Enhanced RAD21 cohesin expression confers poor prognosis and resistance to chemotherapy in high grade luminal, basal and HER2 breast cancers

Introduction: RAD21 is a component of the cohesin complex, which is essential for chromosome segregation and error-free DNA repair. We assessed its prognostic and predictive power in a cohort of in situ and invasive breast cancers, and its effect on chemosensitivity in vitro.Methods: RAD21 immunohistochemistry was performed on 345 invasive and 60 pure in situ carcinomas. Integrated genomic and transcriptomic analyses were performed on a further 48 grade 3 invasive cancers. Chemosensitivity was assessed in breast cancer cell lines with an engineered spectrum of RAD21 expression.Results: RAD21 expression correlated with early relapse in all patients (hazard ratio (HR) 1.74, 95% confidence interval (CI) 1.06 to 2.86, P = 0.029). This was due to the effect of grade 3 tumors (but not grade 1 or 2) in which RAD21 expression correlated with early relapse in luminal (P = 0.040), basal (P = 0.018) and HER2 (P = 0.039) groups. In patients treated with chemotherapy, RAD21 expression was associated with shorter overall survival (P = 0.020). RAD21 mRNA expression correlated with DNA copy number, with amplification present in 32% (7/22) of luminal, 31% (4/13) of basal and 22% (2/9) of HER2 grade 3 cancers. Variations in RAD21 mRNA expression in the clinical samples were reflected in the gene expression data from 36 breast cancer cell lines. Knockdown of RAD21 in the MDA-MB-231 breast cancer cell line significantly enhanced sensitivity to cyclophosphamide, 5-fluorouracil and etoposide. The findings for the former two drugs recapitulated the clinical findings.Conclusions: RAD21 expression confers poor prognosis and resistance to chemotherapy in high grade luminal, basal and HER2 breast cancers. RAD21 may be a novel therapeutic target

Prognostic interaction between expression of p53 and estrogen receptor in patients with node-negative breast cancer: results from IBCSG Trials VIII and IX

Introduction: The prognostic significance of p53 protein expression in early breast cancer remains uncertain, with some but not all studies finding an association with poorer outcomes. Estrogen receptor (ER) expression is both a positive prognostic marker and predictive of response to endocrine therapies. The relationship between these biomarkers is unknown. Methods: We constructed tissue microarrays (TMAs) from available pathological material from 1113 patients participating in two randomized clinical trials comparing endocrine therapy alone versus chemo-endocrine therapy in node-negative breast cancer. Expression of p53 defined as >10% positive nuclei was analyzed together with prior immunohistochemical assays of ER performed at central pathological review of whole tumor sections. Results: ER was present (i.e. >1% positive tumor cell nuclei) in 80.1% (880/1092). p53 expression was significantly more frequent when ER was absent, 125/212 (59%) than when ER was present, 171/880 (19%), p <0.0001. A significant qualitative interaction was observed such that p53 expression was associated with better disease-free survival (DFS) and overall survival (OS) among patients whose tumors did not express ER, but worse DFS and OS among patients whose tumors expressed ER. The interaction remained significant after allowance for pathologic variables, and treatment. Similar effects were seen when luminal and non-luminal intrinsic subtypes were compared. Conclusions: Interpretation of the prognostic significance of p53 expression requires knowledge of concurrent expression of ER. The reason for the interaction between p53 and ER is unknown but may reflect qualitatively different p53 mutations underlying the p53 expression in tumors with or without ER expression. Trial registration Current Controlled Trials ACTRN12607000037404 (Trial VIII) and ACTRN12607000029493 (Trial IX)

SOCS3 Is a Critical Physiological Negative Regulator of G-CSF Signaling and Emergency Granulopoiesis

AbstractTo determine the importance of suppressor of cytokine signaling-3 (SOCS3) in the regulation of hematopoietic growth factor signaling generally, and of G-CSF-induced cellular responses specifically, we created mice in which the Socs3 gene was deleted in all hematopoietic cells. Although normal until young adulthood, these mice then developed neutrophilia and a spectrum of inflammatory pathologies. When stimulated with G-CSF in vitro, SOCS3-deficient cells of the neutrophilic granulocyte lineage exhibited prolonged STAT3 activation and enhanced cellular responses to G-CSF, including an increase in cloning frequency, survival, and proliferative capacity. Consistent with the in vitro findings, mutant mice injected with G-CSF displayed enhanced neutrophilia, progenitor cell mobilization, and splenomegaly, but unexpectedly also developed inflammatory neutrophil infiltration into multiple tissues and consequent hind-leg paresis. We conclude that SOCS3 is a key negative regulator of G-CSF signaling in myeloid cells and that this is of particular significance during G-CSF-driven emergency granulopoiesis

A roadmap for research in post-stroke fatigue: consensus-based core recommendations from the third Stroke Recovery and Rehabilitation Roundtable

Rationale: Fatigue affects almost half of all people living with stroke. Stroke survivors rank understanding fatigue and how to reduce it as one of the highest research priorities. Methods: We convened an interdisciplinary, international group of clinical and pre-clinical researchers and lived experience experts. We identified four priority areas: (1) best measurement tools for research, (2) clinical identification of fatigue and potentially modifiable causes, (3) promising interventions and recommendations for future trials, and (4) possible biological mechanisms of fatigue. Cross-cutting themes were aphasia and the voice of people with lived experience. Working parties were formed and structured consensus building processes were followed. Results: We present 20 recommendations covering outcome measures for research, development, and testing of new interventions and priority areas for future research on the biology of post-stroke fatigue. We developed and recommend the use of the Stroke Fatigue Clinical Assessment Tool. Conclusions: By synthesizing current knowledge in post-stroke fatigue across clinical and pre-clinical fields, our work provides a roadmap for future research into post-stroke fatigue

The Magnitude of Androgen Receptor Positivity in Breast Cancer Is Critical for Reliable Prediction of Disease Outcome

Purpose: Consensus is lacking regarding the androgen receptor (AR) as a prognostic marker in breast cancer. The objectives of this study were to comprehensively review the literature on AR prognostication and determine optimal criteria for AR as an independent predictor of breast cancer survival. Experimental Design: AR positivity was assessed by immunostaining in two clinically validated primary breast cancer cohorts [training cohort, n = 219; validation cohort, n = 418; 77% and 79% estrogen receptor alpha (ERα) positive, respectively]. The optimal AR cut-point was determined by ROC analysis in the training cohort and applied to both cohorts. Results: AR was an independent prognostic marker of breast cancer outcome in 22 of 46 (48%) previous studies that performed multivariate analyses. Most studies used cut-points of 1% or 10% nuclear positivity. Herein, neither 1% nor 10% cut-points were robustly prognostic. ROC analysis revealed that a higher AR cut-point (78% positivity) provided optimal sensitivity and specificity to predict breast cancer survival in the training (HR, 0.41; P = 0.015) and validation (HR, 0.50; P = 0.014) cohorts. Tenfold cross-validation confirmed the robustness of this AR cut-point. Patients with ERα-positive tumors and AR positivity ≥78% had the best survival in both cohorts (P 0.87) had the best outcomes (P < 0.0001). Conclusions: This study defines an optimal AR cut-point to reliably predict breast cancer survival. Testing this cut-point in prospective cohorts is warranted for implementation of AR as a prognostic factor in the clinical management of breast cancer

A comparison of cryopreservation methods: Slow-cooling vs. rapid-cooling based on cell viability, oxidative stress, apoptosis, and CD34+ enumeration of human umbilical cord blood mononucleated cells

<p>Abstract</p> <p>Background</p> <p>The finding of human umbilical cord blood as one of the most likely sources of hematopoietic stem cells offers a less invasive alternative for the need of hematopoietic stem cell transplantation. Due to the once-in-a-life time chance of collecting it, an optimum cryopreservation method that can preserve the life and function of the cells contained is critically needed.</p> <p>Methods</p> <p>Until now, slow-cooling has been the routine method of cryopreservation; however, rapid-cooling offers a simple, efficient, and harmless method for preserving the life and function of the desired cells. Therefore, this study was conducted to compare the effectiveness of slow- and rapid-cooling to preserve umbilical cord blood of mononucleated cells suspected of containing hematopoietic stem cells. The parameters used in this study were differences in cell viability, malondialdehyde content, and apoptosis level. The identification of hematopoietic stem cells themselves was carried out by enumerating CD34⁺in a flow cytometer.</p> <p>Results</p> <p>Our results showed that mononucleated cell viability after rapid-cooling (91.9%) was significantly higher than that after slow-cooling (75.5%), with a <it>p </it>value = 0.003. Interestingly, the malondialdehyde level in the mononucleated cell population after rapid-cooling (56.45 μM) was also significantly higher than that after slow-cooling (33.25 μM), with a <it>p </it>value < 0.001. The apoptosis level in rapid-cooling population (5.18%) was not significantly different from that of the mononucleated cell population that underwent slow-cooling (3.81%), with a <it>p </it>value = 0.138. However, CD34⁺enumeration was much higher in the population that underwent slow-cooling (23.32 cell/μl) than in the one that underwent rapid-cooling (2.47 cell/μl), with a <it>p </it>value = 0.001.</p> <p>Conclusions</p> <p>Rapid-cooling is a potential cryopreservation method to be used to preserve the umbilical cord blood of mononucleated cells, although further optimization of the number of CD34⁺cells after rapid-cooling is critically needed.</p

Inhibition of Mg2+ binding and DNA religation by bacterial topoisomerase I via introduction of an additional positive charge into the active site region

Among bacterial topoisomerase I enzymes, a conserved methionine residue is found at the active site next to the nucleophilic tyrosine. Substitution of this methionine residue with arginine in recombinant Yersinia pestis topoisomerase I (YTOP) was the only substitution at this position found to induce the SOS response in Escherichia coli. Overexpression of the M326R mutant YTOP resulted in ∼4 log loss of viability. Biochemical analysis of purified Y. pestis and E. coli mutant topoisomerase I showed that the Met to Arg substitution affected the DNA religation step of the catalytic cycle. The introduction of an additional positive charge into the active site region of the mutant E. coli topoisomerase I activity shifted the pH for optimal activity and decreased the Mg2+ binding affinity. This study demonstrated that a substitution outside the TOPRIM motif, which binds Mg2+directly, can nonetheless inhibit Mg2+ binding and DNA religation by the enzyme, increasing the accumulation of covalent cleavage complex, with bactericidal consequence. Small molecules that can inhibit Mg2+ dependent religation by bacterial topoisomerase I specifically could be developed into useful new antibacterial compounds. This approach would be similar to the inhibition of divalent ion dependent strand transfer by HIV integrase in antiviral therapy