Brush-like surface using heparin/chitosan based nanoparticles for blood-contacting applications

2013 Summer.Includes bibliographical references.With increasing applications of biomedical implants, it is crucial to develop surfaces that are blood compatible, meaning they do not induce platelet or protein adhesion. Many implants that are currently used to treat a wide range of problems have one major drawback, they can induce thrombosis. The endothelial glycocalyx plays a crucial role in preventing thrombosis. Based on this idea, we set out to develop a surface that has a brush-like structure similar to that of the endothelial glycocalyx. We developed the surface by adsorbing negatively charged heparin/chitosan polyelectrolyte complex nanoparticles onto a heparin/tri-methylchitosan polyelectrolyte multilayer. The surface was then characterized using surface plasmon resonance (SPR), quartz crystal microbalance (QCM), atomic force microsocopy (AFM), scanning electron microscope (SEM), and polarization modulation-infrared reflection absorption spectroscopy (PM-IRRAS). Using these techniques we confirmed that we had created a surface with brush- like structure. Our hypothesis that the nanoparticles on the surface swell and form a brush-like structure when exposed to physiological conditions seems to be correct, as a result, we feel the surface we have developed could have a wide range of applications in the biomedical field

Targeting C-terminal binding proteins (CtBPs) using genetic selection

There are many protein-protein interactions that are vital for cellular processes such as signal transduction, structural organisation and apoptosis. In this study we decipher the role of the protein-protein interaction of C terminal Binding Proteins (CtBPs). CtBPs function as transcriptional co-repressors in the nucleus playing key roles in tumorigenesis and metastasis by regulating cellular processes, critical to cell survival, cell migration and senescence. CtBP proteins also play a role in the cytoplasm in regulating mitotic Golgi membrane fission Studies in which the expression or function of CtBPs has been inhibited have independently identified roles for CtBPs in both suppressing apoptosis and promoting cell cycle progression. Modulation of these interactions with small molecules is a potential therapeutic strategy with benefits over current methods. Our approach in studying protein-protein interactions and uncovering potential inhibitors involves constructing a bacterial Reverse Two Hybrid System (RTHS) linking the dimerisation of the target protein partners to the expression of reporter genes, whose regulation can be monitored via host survival. Subsequent screening of a cyclic peptide library for potential inhibitors was then carried out. The libraries were produced using Split Intein-mediated Circular Ligation Of Peptides and Proteins (SICLOPPS) technology, developed for intracellular synthesis of cyclic peptides. We have used this methodology to identify inhibitors of CtBP dimerisation and better understand the roles of this protein interaction in cell cycle regulation. Chapter 1 provides an introduction to the work carried out to study protein-protein interactions and finding potential inhibitors. Since our investigations involved the extensive use of the RTHS and SICLOPPS system, the background and work performed by others has been described in detail. A detailed review of CtBPs has also been carried out. Chapter 2 details our work investigating the homodimeric and heterodimeric protein-protein interaction of CtBPs using the RTHS. This work allowed us to optimise selection conditions and find cyclic peptide inhibitors of the homodimerisation of CtBP1 and CtBP2 using the SICLOPPS process. The synthesis of these inhibitors is described. Chapter 3 details our work carried out to develop ELISAs for in vitro analysis of the selected cyclic peptides. This involved the purification of His- and GST-tagged CtBP1 and CtBP2 proteins. The ELISA conditions were optimised to carry out CtBP homodimeric and hetrodimeric analysis. This work showed that the peptides lead to a reduction in CtBP homdimerisation and heterodimerisation in vitro. Chapter 4 details the in vivo effects of the uncovered CtBP dimerisation inhibitors. Using these cyclic peptide inhibitors we have demonstrated that CtBP dimerisation is essential for the regulation of mitotic fidelity, and that inhibition of CtBP dimerisation by the cyclic peptides leads to aberrant segregation of chromosomes during mitosis. We have also shown that inhibition of CtBP dimerisation leads to a reduction in migration of MCF-7 breast cancer cells. Chapter 5 details the experimental procedures used in this work and presents spectroscopic and analytical data for the compounds prepared

Paradigms lost and gained: stakeholder experiences of crisis distance learning during the Covid-19 pandemic

The physical distancing requirements designed to slow the contagion of COVID-19 instigated sweeping changes to the education sector. School closures in 193 countries brought significant disruption to education and to the lives of children, parents, and teachers. This study explored the experiences of school stakeholders during this period of crisis distance learning (DL). The perspectives of participants in six discrete focus groups of pupils, parents, and teachers at a private school in Dubai, United Arab Emirates, were subject to thematic analysis. Researchers identified three key themes, including ‘a need for stakeholder support’, ‘curriculum delivery implications’, and ‘educational outcomes of crisis distance learning’. Conclusions and recommendations will be of interest to researchers, teachers, school leaders, and teacher education providers

Imaging in gynecological disease: clinical and ultrasound characteristics of intramural pregnancy

OBJECTIVE: To describe the clinical and sonographic characteristics of intramural pregnancies, the available management options and treatment outcomes. METHODS: This was a retrospective single-center study of consecutive patients diagnosed by ultrasound with an intramural pregnancy, between 2008 and 2022. An intramural pregnancy was diagnosed on ultrasound examination when a pregnancy located within the confines of the uterus, extended beyond the decidual-myometrial junction to involve the myometrium above the level of the internal cervical os. Clinical, ultrasound, relevant surgical and histological information and outcomes were retrieved from each patient's record. RESULTS: Eighteen patients diagnosed with an intramural pregnancy were identified. Median age was 35 (range, 28-43) years. Median gestational age was 8+1 (range, 5+5 - 12+0 ) weeks. Vaginal bleeding with or without abdominal pain was the most common presenting symptom, which was recorded in 8/18 (44%) of patients. 9/18 (50%) of patients had partial and 9/18 (50%) complete intramural pregnancies. Embryonic cardiac activity was present in 8/18 (44%) of pregnancies. The majority of pregnancies [10/18 (56%)] were initially managed conservatively, including expectant management [8/18 (44%)], local injection of methotrexate [1/18 (6%)] and embryocide [1/18 (6%)]. Conservative management was successful in 9/10 (90%) of women with a median hCG resolution time of 71 (range, 32-143) days and median pregnancy resolution time of 63 (range, 45-214) days. One patient with an ongoing live pregnancy had an emergency hysterectomy for a major vaginal bleed at 20 weeks' gestation. No other patients who were managed conservatively experienced any significant complications. The remaining 8/18 (44%) patients had primary surgical treatment, which was mainly in the form of transcervical suction curettage [7/8 (88%)] whist the remaining patient presented with uterine rupture and had an emergency laparoscopy and repair. CONCLUSIONS: We describe the ultrasound features for partial and complete intramural pregnancies with demonstration of key diagnostic features. Our series suggest that when intramural pregnancies are diagnosed before 12 weeks' of gestational age they can be managed with either conservative or surgical treatment, with most women being able to preserve their future reproductive function. This article is protected by copyright. All rights reserved

Psychosocial risk factors and health outcomes in the offspring of parents with bipolar disorder in adolescence and young adulthood: A 10-year longitudinal study

It is well known that the offspring of parents with bipolar disorder (OBD) are at heightened risk of developing mental disorders, particularly the affective disorders. However, we have much less information about deleterious non-psychiatric outcomes, such a health-risk behaviors, and the family-environmental risk factors associated with negative outcomes in the OBD. It has been proposed that the OBD, through genetic mechanisms and early family interactions, develop a heightened sensitivity to stress, maladaptive coping, and dysregulated behavior, which ultimately increases the risk for affective disorders. The current dissertation was designed to test parts of this model by conducting a comprehensive assessment of social risk factors, personality, and mental health in the OBD, and to examine putative antecedents of negative outcomes in the OBD using 10-year longitudinal data. The first study within this dissertation assessed different psychosocial and health-related outcomes in the OBD, including mental health, personality, coping style, smoking, suicidality, high-risk sexual behaviors, criminality, and mental health. These factors were compared across affected and unaffected offspring in order to differentiate potential prodromal markers from correlates of mood episodes. It was found that unaffected OBD engaged in less task-oriented and more avoidant coping strategies than controls. Furthermore, after controlling for current affective disorders, the OBD were more likely than controls to engage in sexual risk behaviors (SRBs). In the second study, parents’ personality, specifically high neuroticism, was assessed to determine whether it predicted SRBs among the offspring 10 years later, and whether the relationship between parents’ personality and offspring SRBs was mediated by behavioral problems in middle childhood. High neuroticism, low agreeableness, and low extraversion in the parents predicted SRBs in their offspring in late adolescence-early adulthood. The offspring’s externalizing problems in middle childhood partly mediated the association between parents’ personality and offspring SRBs. The findings highlight a risk profile in the OBD characterized by poor stress coping and engagement in risky sexual behaviors. Furthermore, SRBs were related to a developmental trajectory that included markers of family stress and early externalizing problems. Together, these studies highlight the importance of behavior problems as markers of vulnerability in the OBD. Importantly, this pattern of results emphasizes the need for targeted, early interventions aimed at increasing familial stability and stress management before the development of behavioral problems

Automatic information processing and stress in the natural environment : an emotion-modulated startle response study

Positive interpersonal relationships are integral to individuals' mental health and well being. Biases in the automatic processing of threatening social stimuli has been suggested as one mechanism that puts people at risk for greater dysfunction in interpersonal realms. The present study sought to explore this relationship using the emotion-modulated startle paradigm, a well-validated measure of automatic processing and defensive motivational system activation. Three separate objectives were addressed: (1) whether angry and happy facial images would differentially modulate the eye-blink startle response, (2) whether the emotion-modulated startle response to angry faces predicts the experience of chronic stress and stressful life events (SLEs) in the natural environment, as determined by the UCLA Chronic and Episodic Life Stress Interview, and (3) whether the relationship between the emotion-modulated startle response and indices of stress is moderated by depression scores. Results indicate that those who exhibit greater startle magnitude to angry faces also experience greater chronic stress and SLEs in non-interpersonal realms. Furthermore, depression and startle magnitude were seen to interact in the prediction of non-interpersonal stress such that high startle was predictive of stress in those with low depression scores. This study is among the first to demonstrate a relationship between psychophysiological measures of attention and the experience of stress in the natural environment, opening up avenues for future investigation

Macrophages and CD4 T-cells in rheumatoid arthritis and their modulation by JAK inhibitors

Background: Rheumatoid arthritis (RA) is a chronic inflammatory arthritis that causes significant morbidity and mortality and has no cure. Although early treatment strategies and biologic therapies such as TNFα blocking antibodies have revolutionised treatment, there still remains considerable unmet need. JAK kinase inhibitors, which target multiple inflammatory cytokines, have shown efficacy in treating RA although their exact mechanism of action remains to be determined. Stratified medicine promises to deliver the right drug to the right patient at the right time by using predictive ‘omic biomarkers discovered using bioinformatic and “Big Data” techniques. Therefore, knowledge across the realms of clinical rheumatology, applied immunology, bioinformatics and data science is required to realise this goal. Aim: To use bioinformatic tools to analyse the transcriptome of CD14 macrophages derived from patients with inflammatory arthritis and define a JAK/STAT signature. Thereafter to investigate the role of JAK inhibition on inflammatory cytokine production in a macrophage cell contact activation assay. Finally, to investigate JAK inhibition, following RA synovial fluid stimulation of monocytes. Methods and Results: Using bioinformatic software such as limma from the Bioconductor repository, I determined that there was a JAK/STAT signature in synovial CD14 macrophages from patients with RA and this differed from psoriatic arthritis samples. JAK inhibition using a JAK1/3 inhibitor tofacitinib reduced TNFα production when macrophages were cell contact activated by cytokine stimulated CD4 T-cells. Other pro-inflammatory cytokines such as IL-6 and chemokines such as IP-10 were also reduced. RA synovial fluid failed to stimulate monocytes to phosphorylate STAT1, 3 or 6 but CD4 T-cells activated STAT3 with this stimulus. RNA sequencing of synovial fluid stimulated CD4 T-cells showed an upregulation of SOCS3, BCL6 and SBNO2, a gene associated with RA but with unknown function and tofacitinib reversed this. Conclusion: These studies demonstrate that tofacitinib is effective at reducing inflammatory mediator production in a macrophage cell contact assay and also affects soluble factor mediated stimulation of CD4 T-cells. This suggests that the effectiveness of JAK inhibition is due to inhibition of multiple cytokine pathways such as IL-6, IL-15 and interferon. RNA sequencing is a useful tool to identify non-coding RNA transcripts that are associated with synovial fluid stimulation and JAK inhibition but these require further validation. SBNO2, a gene that is associated with RA, may be biomarker of tofacitinib treatment but requires further investigation and validation in wider disease cohorts

Young, Wild*, and (somewhat) Free: A Narrative Exploration of Married Second- Generation East Indian Canadian Women and Their Relationship with Leisure

Stemming from my personal experiences of a second-generation East Indian (SGEI) woman living in Canada, I explore the complexities of leisure within marriages. I employ postcolonial feminist theorization to contextualize the Other identity and how power relations function to change women’s leisure behaviour. Deepening our understanding of these discourses, I employed narrative inquiry to bring married SGEI Canadian’s women’s counter-narratives to the fore. Using eight one-on-one interviews with married SGEI women ages 18-35 living in the Greater Toronto Area, I illustrate these women’s counter-narratives in dialogue-based vignettes to demonstrate the multiplicities of their experiences. Highlighting the similarities, and variations in four areas: The Other and Marriage, The Other and Performance, The Other and Agency, and The Other and Judgment. Together, the findings detail the competing discourses working to Other the married SGEI Canadian women’s identity. More specifically, East Indian marriages complicate gender role expectations through added pressures of the honour gaze and surveillance mechanisms that discipline our actions. Women use agency and negotiation to resist, challenge, and manipulate power structures through leisure activities. Given that the voices of married SGEI Canadian women have been ignored in leisure literature, this research contributes to the importance of understanding the reasons behind our leisure actions and, why we do what we do

Comparison of Communications Styles Amongst Students in Allied Health Professions Programs: How Do Our Students Communicate with Other Healthcare Providers?

Background: Optimal patient outcomes require communication between providers in multiple professions to initiate referrals, communicate patient treatment, and coordinate care. While there is a clear need for increased understanding of the terminology, skills, and scopes of practice of professional colleagues, these tools are of limited effectiveness if there is poor interpersonal communication between team members. Multiple bodies for Interprofessional Practice and Education (IPP/IPE) identify communication skills as an integral part of education. In fact, the third competency domain set down by the Interprofessional Education Collaborative, Interprofessional Communication, states that professionals should, “Recognize how one’s own uniqueness, including experience level, expertise, culture, power, and hierarchy within the healthcare team, contributes to effective communication, conflict resolution, and positive interprofessional working relationships” [1].Methods and Findings: As part of a required interprofessional competence course, first-year students in ten health professions programs completed the Personal Coaching Style Inventory (PSCI) to self-identify personal communication styles. A series of one-way analysis of variance (ANOVA) analyses followed by Tukey post-hoc analyses were performed in order to identify significant differences in PSCI component scores between programs. Within groups, students discussed personal and cohort-wide findings as they impact teamwork. The majority of students identified with the Mediator style. Differences in style were also found in relation to profession, gender, and race. The activity prompted discussion of varied roles in team dynamics, and how differences in style could affect interprofessional teamwork.Conclusions: Self-awareness of personal communication styles as well as predominant styles of other health professions may enhance interprofessional communication\skills. The skill with which students approach their team roles in heterogeneous groups following graduation has the potential to increase team functionality and patient outcomes

Gestion des anticoagulants : une formation interdisciplinaire pour les résidents en médecine familiale

Implication Statement Anticoagulants are high-risk medications with the potential to cause significant patient harm if inappropriately managed. Medical trainees and practicing physicians often report inadequate education and uncertainty in decision-making related to anticoagulation therapy. To address this gap, an interdisciplinary Anticoagulation Management Training Program was developed for family medicine residents at the Toronto Western Family Health Team. Evaluation data demonstrated both improved knowledge and confidence in prescribing, monitoring, and adjusting anticoagulation therapy. This suggests that similar dedicated curricula be considered in other family medicine programs in order to optimize patient safety by enhancing the knowledge and self-efficacy of future practising physicians.Énoncé des implications de la recherche Les anticoagulants sont des médicaments à haut risque qui, mal gérés, peuvent causer des dommages importants aux patients. De nombreux étudiants en médecine et médecins en exercice déclarent que leur formation est inadéquate et qu’ils ont des doutes lorsqu’ils prescrivent un traitement anticoagulant. Pour combler cette lacune, une formation interdisciplinaire en gestion des anticoagulants a été élaborée pour les résidents en médecine familiale au sein de la Toronto Western Family Health Team. Les données d’évaluation de la formation indiquent une amélioration sur le plan des connaissances et de la confiance lors de la prescription, ainsi que sur celui du suivi et de l’ajustement de l’anticoagulothérapie. Ces résultats suggèrent qu’il serait donc pertinent d’envisager l’introduction de formations spécialisées de ce type dans les programmes de médecine familiale pour mieux assurer la sécurité des patients par le développement des connaissances et de l’auto-efficacité des futurs praticiens