Translational studies on the vascular targeting agent combretastatin A4 phosphate

This thesis describes in vitro experiments with the novel vascular targeting agent Combretastatin A4 Phosphate (CA4P) and non-invasive magnetic resonance imaging (MRI) measurements in patients treated with CA4P to derive parameters which reflect tumour and normal tissue blood flow and permeability. Shape changes induced following tubulin depolymerisation by CA4P are quantified in human umbilical vein endothelial cells (HUVECs) and are measurable after only 10 minutes exposure. The effect is more marked in proliferating than confluent HUVECs, and begins at doses that have no anti-proliferative activity. In contrast, human smooth muscle cells show no shape change after treatment. The similar time course of HUVEC shape changes in vitro and tumour vascular shutdown in vitro suggest that this might be an early event involved in vascular shutdown. The effects and recovery rates of several other tubulin-binding agents are compared with CA4P. Colchicine and vinblastine also induce changes in HUVEC shape but unlike CA4P, HUVECs do not recover after drug removal. For these drugs, shape change and antiproliferative effects occur at similar doses. ZD6126, which like CA4P also has vascular targeting activity at well tolerated doses, induces recoverable changes in HUVEC shape at doses with no anti-proliferative activity. The difference in recovery rates with different tubulin-binding agents might therefore be related to their therapeutic window. The reproducibility of dynamic contrast enhanced MRI is measured in 21 patients who had 2 pre treatment scans within a week. Comparing the technique in rats with an established method for measuring absolute blood flow provides verification that the kinetic parameters derived from this technique reflect blood flow changes. Significant reductions in these parameters in patients' tumours are seen 4 and 24 hours after treatment at well tolerated doses of CA4P at 52mg/m2 to 68 mg/m2. No significant mean changes are seen in kidney, liver, spleen or skeletal muscle, although a small proportion of patients have significant reductions which are generally not maintained, and not associated with clinical consequences

REPRODUCTION IN A CHANGING ENVIRONMENT: MUSSELS, IMPOUNDMENTS, AND CONSERVATION

As humans alter the environmental landscape, there is an increasing need to understand the relationship between species and the environment, how changes to the environment translate to populations and communities, and how to develop management practices that reduce or reverse our negative impacts. Different animals respond differently to environmental change as do different developmental life stages within the same species. Reproduction, for example, is often the most sensitive time period of an organism's life, yet has been largely ignored in conservation biology, partly due to the difficulties in studying reproduction (e.g. complex life cycles, migration, delayed reproduction). Nonetheless, it is vitally important that we have some basic understanding of the reproductive process in order to facilitate sound management of critically imperiled fauna. Freshwater mussels are one such globally imperiled group of invertebrates with over 70% of species considered threatened. However, very little is understood about their complex life cycle, particularly the portion of reproduction up to and including fertilization. The research detailed in my dissertation broadens our understanding of this portion of the mussel reproductive cycle and how it is being impacted by humans.My first chapter explores the environmental variables that are important in regulating timing of gametogenesis in mussels. Using a year-long field sampling regime I found that water temperature, and in particular the number of degree days during which growth occurs, is an important correlate for the number of mature gametes present in adult mussel's gonadal tissue. Using a 3-month long laboratory study I confirmed these findings; however, I also discovered the potential for a food quality by temperature interaction in this study as mussels in my experiment were fed high quality food and had substantially more gametes present in their gonads than were ever observed in the field.My second chapter explores how environmental variables affect the process of fertilization in freshwater mussels. I conducted a sperm viability experiment in which I manipulated water temperature (5, 15, 25, and 35oC) and measured the percentage of viable mussel sperm that were motile over time. I found that mussel sperm are viable for extensive periods of time, but that the highest motility was observed in the 15 and 25oC temperature range. I combined these data with a modeling approach to determine how mussel population dynamics and gene flow could be impacted by different thermal and flow regimes. I discovered that mussel sperm has the potential to move extremely long distances downstream, but that ultimately sperm transport is a function of stream velocity and height above the sediment at which sperm are released. Reproductive success, however, is a function of the proportion of sperm that have remained viable over time.The research detailed in my third chapter examines the role of impoundments on the reproductive success and population attributes of freshwater mussels. Using data collected in my year-long field study, I found that mussels below a cold-water release impoundment had lower overall mussel densities, higher proportions of hermaphroditic individuals, higher prevalence of sterilizing trematodes, and lower body condition relative to mussels found above the impoundment. I also found that patterns in timing of gamete development were also unusual below the cold-water release dam. I outline a conceptual model by which alterations in temperature, stream flow, light, and food availability caused by impoundments could lead to overall negative density-dependence in mussel populations. These first three chapters illustrate the importance of natural temperature and flow regimes in maintaining healthy reproduction in freshwater mussel communities, information that is critical for managing rivers that provide habitat to mussels.As humans continue to alter riverine landscapes, we are also likely to impact the evolutionary trajectories of species residing there. Unfortunately, another aspect of mussel biology that is also understudied is the evolution of the great diversity of freshwater mussels, particularly in North America. Several evolutionary hypotheses have been proposed for the evolution of these organisms, yet none have been tested. The goal of my fourth chapter was to address freshwater mussel evolution from the perspective of mechanisms of reproductive isolation, since barriers must exist between species to maintain distinct species identities. I examined the role that habitat use and timing of reproduction may play in isolating co-occurring, closely related mussel species of the genus Quadrula. I found that habitat overlap among closely related species varies (although is often high), but could be one isolating mechanism. Timing of reproduction, however, overlaps almost entirely among these species and is likely not a factor maintaining species identity in this genus. Further research into other isolating mechanisms is required to increase our understanding of reproductive barriers and evolution of freshwater mussels

The association between individual counselling and health behaviour change: the See Kidney Disease (SeeKD) targeted screening programme for chronic kidney disease

Background: Health behaviour change is an important component of management for patients with chronic kidney disease (CKD); however, the optimal method to promote health behaviour change for self-management of CKD is unknown. The See Kidney Disease (SeeKD) targeted screening programme screened Canadians at risk for CKD and promoted health behaviour change through individual counselling and goal setting. Objectives: The objectives of this study are to determine the effectiveness of individual counselling sessions for eliciting behaviour change and to describe participant characteristics associated with behaviour change. Design: This is a cross-sectional, descriptive study. Setting: The study setting is the National SeeKD targeted screening programme. Patients: The participants are all ‘at risk’ patients who were screened for CKD and returned a follow-up health behaviour survey ( n = 1129). Measurements: Health behaviour change was defined as a self-reported change in lifestyle, including dietary changes or medication adherence. Methods: An individual counselling session was provided to participants by allied healthcare professionals to promote health behaviour change. A survey was mailed to all participants at risk of CKD within 2-4 weeks following the screening event to determine if behaviour changes had been initiated. Descriptive statistics were used to describe respondent characteristics and self-reported behaviour change following screening events. Results were stratified by estimated glomerular filtration rate (eGFR) (60 mL/min/1.73 m 2 ). Log binomial regression analysis was used to determine the predictors of behaviour change. Results: Of the 1129 respondents, the majority (89.8 %) reported making a health behaviour change after the screening event. Respondents who were overweight (body mass index [BMI] 25-29.9 kg/m 2 ) or obese (BMi ≥ 30.0 kg/m 2 ) were more likely to report a behaviour change (prevalence rate ratio (PRR) 0.66, 95 % confidence interval (CI) 0.44-0.99 and PRR 0.49, 95 % CI 0.30-0.80, respectively). Further, participants with a prior intent to change their behaviour were more likely to make a behaviour change (PRR 0.58, 95 % CI 0.35-0.96). Results did not vary by eGFR category. Limitations: We are unable to determine the effectiveness of the behaviour change intervention given the lack of a control group. Potential response bias and social desirability bias must also be considered when interpreting the study findings. Conclusions: Individual counselling and goal setting provided at screening events may stimulate behaviour change amongst individuals at risk for CKD. However, further research is required to determine if this behaviour change is sustained and the impact on CKD progression and outcomes

Guaranteeing Canadian lamb meat quality using near-infrared spectroscopy on intact rack

Lamb racks from commercial carcasses were scanned using near-infrared spectroscopy. The prediction accuracies (R 2) for meat quality traits were assessed. Prediction accuracy ranged between 0.40 and 0.94. When predicted values were used to classify meat based on quality, 88.7%–95.2% of samples were correctly classified as quality guaranteed

Comorbidity between lung cancer and COVID-19 pneumonia: role of immunoregulatory gene transcripts in high ACE2-expressing normal lung

ACE2 expression; COVID-19; CancerExpresión ACE2; COVID-19; CáncerExpressió ACE2; COVID-19; CàncerBackground: SARS-CoV-2 (COVID-19) elicits a T-cell antigen-mediated immune response of variable efficacy. To understand this variability, we explored transcriptomic expression of angiotensin-converting enzyme 2 (ACE2, the SARS-CoV-2 receptor) and of immunoregulatory genes in normal lung tissues from patients with non-small cell lung cancer (NSCLC). Methods: This study used the transcriptomic and the clinical data for NSCLC patients generated during the CHEMORES study [n = 123 primary resected (early-stage) NSCLC] and the WINTHER clinical trial (n = 32 metastatic NSCLC). Results: We identified patient subgroups with high and low ACE2 expression (p = 1.55 × 10−19) in normal lung tissue, presumed to be at higher and lower risk, respectively, of developing severe COVID-19 should they become infected. ACE2 transcript expression in normal lung tissues (but not in tumor tissue) of patients with NSCLC was higher in individuals with more advanced disease. High-ACE2 expressors had significantly higher levels of CD8+ cytotoxic T lymphocytes and natural killer cells but with presumably impaired function by high Thymocyte Selection-Associated High Mobility Group Box Protein TOX (TOX) expression. In addition, immune checkpoint-related molecules – PD-L1, CTLA-4, PD-1, and TIGIT – are more highly expressed in normal (but not tumor) lung tissues; these molecules might dampen immune response to either viruses or cancer. Importantly, however, high inducible T-cell co-stimulator (ICOS), which can amplify immune and cytokine reactivity, significantly correlated with high ACE2 expression in univariable analysis of normal lung (but not lung tumor tissue). Conclusions: We report a normal lung immune-tolerant state that may explain a potential comorbidity risk between two diseases – NSCLC and susceptibility to COVID-19 pneumonia. Further, a NSCLC patient subgroup has normal lung tissue expressing high ACE2 and high ICOS transcripts, the latter potentially promoting a hyperimmune response, and possibly leading to severe COVID-19 pulmonary compromise.FundingThe authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The research leading to these results on the CHEMORES study data, an initiative from the Chemotherapy resistance consortium, has received funding from the European Union Sixth Framework (FP6) Integrated Project. The research on the WINTHER trial data leading to these results has received funding from the European Union Seventh Framework Program (FP7) (WINTHER: FP7/2007-2013 under grant agreement n°306125). WINTHER, an initiative from the WIN Consortium, was funded in part by ARC Foundation for cancer research (France), Pfizer Oncology, Lilly France SAS, and Novartis Pharmaceuticals Corporation. Funded in part by The FERO/J.P. Morgan Private Bank Clinical Oncology Research Grant, National Cancer Institute grant P30 P30-CA023100 (RK), Israeli Science Foundation grant 1188/16 (ER), Instituto Salud Carlos III – Programa Rio Hortega Contract grant CM15/00255 (EF) and Canadian Institutes for Health Research (grant MOP-142281, GB) and the Canadian Cancer Society (grant 703811, GB)

Transcriptomics in Tumor and Normal Lung Tissues Identify Patients With Early-Stage Non–Small-Cell Lung Cancer With High Risk of Postsurgery Recurrence Who May Benefit From Adjuvant Therapies

Terapias adyuvantes; Cáncer de pulmón; PronósticoTeràpies adjuvants; Càncer de pulmó; PronòsticAdjuvant therapies; Lung cancer; PrognosisPURPOSE The prognosis of patients with non–small-cell lung cancer (NSCLC), traditionally determined by anatomic histology and TNM staging, neglects the biological features of the tumor that may be important in determining patient outcome and guiding therapeutic interventions. Identifying patients with NSCLC at increased risk of recurrence after curative-intent surgery remains an important unmet need so that known effective adjuvant treatments can be offered to those at highest risk of recurrence. METHODS Relative gene expression level in the primary tumor and normal bronchial tissues was used to retrospectively assess their association with disease-free survival (DFS) in a cohort of 120 patients with NSCLC who underwent curative-intent surgery. RESULTS Low versus high Digital Display Precision Predictor (DDPP) score (a measure of relative gene expression) was significantly associated with shorter DFS (highest recurrence risk; P = .006) in all patients and in patients with TNM stages 1-2 (P = .00051; n = 83). For patients with stages 1-2 and low DDPP score (n = 29), adjuvant chemotherapy was associated with improved DFS (P = .0041). High co-overexpression of CTLA-4, PD-L1, and ICOS in normal lung (28 of 120 patients) was also significantly associated with decreased DFS (P = .0013), suggesting an immune tolerance to tumor neoantigens in some patients. Patients with DDPP low and immunotolerant normal tissue had the shortest DFS (P = 2.12E–11). CONCLUSION TNM stage, DDPP score, and immune competence status of normal lung are independent prognostic factors in multivariate analysis. Our findings open new avenues for prospective prognostic assessment and treatment assignment on the basis of transcriptomic profiling of tumor and normal lung tissue in patients with NSCLC

Pine sawdust biochar as a potential amendment for establishing trees in Appalachian mine spoils

Early growth and survival of tree seedlings is often poor on reclaimed coal surface mines in Appalachia. Biochar produced in bioenergy generation has potential for use as an amendment to improve seedling performance. Mine soil was collected from a recently reclaimed coal surface mine in Wise County, Virginia and mixed with loblolly pine (Pinus taeda L.) sawdust biochar, simulating application rates of 2.3, 11.2 and 22.5 Mg ha-1. Unplanted leaching columns and 4 L tree planting pots were filled with these biochar-soil mixtures, plus controls of pure mine soil and pure biochar. For the tree planting pots, additional pots were created where the biochar was applied as a topdressing at the same application rates as in the mixtures. One-year-old seedlings of both American sycamore (Platanus occidentalis L.) and black locust (Robinia pseudoacacia L.) were planted. Unplanted leaching columns were leached with collected rainwater for six months to simulate weathering. Trees were grown for one growing season. Black locust had higher average above-ground dry woody biomass (24.4 g) than American sycamore (17.0 g), and also higher below-ground biomass (61.0 g compared to 30.2 g). The pure biochar produced greater average below-ground biomass (99.9 g) than the pure mine soil (46.9 g). All of the biochar treatments produced greater average above-ground woody biomass (19.1 g – 33.4 g) than the pure mine soil (10.9 g). After weathering, biochar provided less available soil phosphorus, calcium and iron than the mine soil itself while increasing soil carbon and organic matter. High (22.5 Mg ha-1) biochar applications increased soil volumetric water holding capacity to 18.6% compared to 13.4% for pure mine soil. Naturally-occurring herbaceous biomass in the pots was negatively correlated with above-ground woody biomass at r = -0.483. Topdressing and full incorporation of biochar were not significantly different in their effects on biomass. Results suggest that pine biochar either broadcast at 2.3 - 22.5 Mg ha‑1, or mixed in planting holes with backfill soil, will promote faster above-ground growth and larger root systems in seedlings in mine soils. Further studies should test these methods in the field over multiple years and further refine recommendations of the rate of biochar to use and how best to apply it. New systems are being developed in Appalachia to produce biofuels and biochar from local biomass and to recycle biochar into the land base to enhance future biomass productivity. Applying 4 L of biochar mixed with the backfill of newly-planted trees is the top recommended practice for tree performance

Women in physics in the United States: Recruitment and retention

Initiatives to increase the number, persistence, and success of women in physics in the United States reach preteen girls through senior women. Programs exist at both the local and national levels. In addition, researchers have investigated issues related to gender equity in physics and physics education. Anecdotal evidence suggests increased media coverage of the underrepresentation of women in science. All of these efforts are motivated and made more effective by the continued collection and presentation of data on the presence, persistence, and promise of women in physics

LASSO model selection with post-processing for a genome-wide association study data set

Model selection procedures for simultaneous analysis of all single-nucleotide polymorphisms in genome-wide association studies are most suitable for making full use of the data for a complex disease study. In this paper we consider a penalized regression using the LASSO procedure and show that post-processing of the penalized-regression results with subsequent stepwise selection may lead to improved identification of causal single-nucleotide polymorphisms