An efficient micropropagation protocol for large scale production of hazelnut plants is required for consistent supply of elite germplasm to support the growing industry in Ontario. The main focus of current research was to develop a bioreactor based micropropagation protocol for hazelnut multiplication. An integrated approach was developed to increase the multiplication rate by optimizing the nutrient medium supplements and culture technology using a temporary immersion bioreactor system (TIS). As compared to conventional semi-solid and liquid based culture system, the Liquid LabTM temporary immersion bioreactor system (LIS) showed a significant enhancement in the number of shoots (3.3 shoots/explant), shoot height, leaf area and chlorophyll content in micropropagated plantlets. Antioxidant supplements such as ascorbic acid and melatonin along with iron (460 µM FeEDDHA) significantly increased the shoot proliferation (5.5 shoots/explant). However, a much higher shoot proliferation (10.9 shoots/explant) was observed with the addition of aspirin (10 µM) in the presence of BA (17.6 µM). Among several hazelnut cultivars, HF-16 had the highest multiplication rate followed by Geneva and Epsilon. Medium supplemented with 10 µM IBA was the best for rooting of microshoots of HF-16 and the plantlets acclimatized in the green house with 80% survival rate. / Ontario Ministry of Agriculture and Food and Rural Affairs

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 4 uppsatser.

The objective of the work presented in this thesis was to explore the role of potential alternatives to platelet transfusions and specifically to investigate whether desmopressin could be used for treatment of thrombocytopenia or platelet dysfunction. Patients with thrombocytopenia or platelet dysfunction are often treated with platelet transfusions to treat or prevent bleeding. However the evidence for the efficacy of platelet transfusion is limited and there is some evidence of harm. I have focused on thrombocytopenic patients with haematological malignancies or critically ill patients, who are amongst the groups most commonly treated with platelet transfusions. The aims of this research were to determine: 1. If levels of Von Willebrand factor (VWF) or other measures of haemostasis are predictive of bleeding in severe thrombocytopenia; 2. Whether VWF compensates for thrombocytopenia in vitro; 3. The evidence for the efficacy of desmopressin in all patients undergoing surgery or invasive procedures; 4. The evidence for desmopressin for platelet dysfunction or thrombocytopenia; 5. If it is feasible to use desmopressin to treat critically ill thrombocytopenic patients in a clinical trial. To identify derangements of haemostasis that may signify candidates for alternatives to platelet transfusions, I analysed blood samples from an observational trial of fifty patients with haematological malignancies and profound thrombocytopenia due to intensive chemotherapy. I used a panel of tests to investigate measures of primary haemostasis, thrombin generation, cross-linked fibrin formation and fibrinolysis. Using multivariable logistic regression, I found no consistent correlation between any measures of haemostasis and the risk of clinically significant bleeding. VWF antigen levels were the best predictor of clinically significant bleeding on the same day (odds ratio 0.31, 95% confidence interval 0.10 to 0.98, p=0.047) but were not predictive of severe bleeding over the 24 hours after the test (odds ratio 0.48, 95% confidence interval 0.10 to 2.34, p=0.36). In a separate set of experiments, I evaluated thrombus formation under flow in thrombocytopenia. This technique was sensitive to the platelet count . Addition of exogenous VWF to thrombocytopenic blood resulted in improvement in thrombus formation, suggesting that agents that affect or influence VWF pathways might have a role. Desmopressin can be used to increase VWF levels, so leading on from my laboratory experiments; I used systematic reviews and meta-analyses to assess whether desmopressin could be used in unselected patients to reduce bleeding peri-operatively. I identified 62 randomised controlled trials. Overall there was no evidence of benefit for administering desmopressin to unselected patients. However further analysis of eleven randomised controlled trials that focused on patients with platelet dysfunction found that desmopressin resulted in transfusion of fewer units of red cells (equivalent to a 25% reduction compared to control), less blood loss (equivalent to a 23% reduction compared to control) and a lower risk of requiring a re-operation due to bleeding (Peto odds ratio 0.39, 95% confidence interval 0.18 to 0.84). There was no evidence for an increase in thrombotic events. There was no randomised controlled trial evidence for perioperative desmopressin for patients with thrombocytopenia. These specific research gaps were addressed by designing new clinical trials. I have commenced a randomised controlled feasibility trial of desmopressin versus placebo for critically ill patients with thrombocytopenia undergoing invasive procedures. This trial is ongoing and is the first randomised trial evaluating peri-procedural desmopressin in thrombocytopenia. The programme of work arising from this research has the potential to benefit a large number of patients by preventing bleeding and reducing exposure to allogeneic blood components such as platelets. The results presented in this thesis are exploratory but are an important step on a path towards larger trials using desmopressin as an alternative, or adjunct to platelet transfusion.

Colorectal cancer (CRC) is the fourth most common cause of cancer related deaths in the UK with the prognosis dependent on the degree of tumour invasion and presence of metastasis at diagnosis. An important step in the invasion and metastasis of solid tumours is the loss of cell-cell junctions and the acquirement of a more motile mesenchymal phenotype which is facilitated by the epithelial-mesenchymal transition (EMT). The presence of EMT is linked with a more aggressive, invasive tumour and subsequent poor prognosis. In addition to roles in motility and invasion, EMT can induce a cancer stem cell phenotype in a subset of tumour cells. Cancer stem cells (CSCs) are a subpopulation of cells capable of self-renewal and maintaining a cellular population whilst displaying increased therapeutic resistance. Induction of EMT and CSCs can be regulated by common signalling pathways with expression of EMT transcription factors inducing CSCs expression. Understanding the signalling pathways regulating EMT and CSC formation in cancer is important for preventing of metastasis and combating therapeutic resistance. Aspirin’s role in cancer prevention has been established for a number of years with aspirin treatment reducing the incidence of CRC. Recently, evidence has emerged suggesting aspirin treatment may have post-diagnosis benefits and increase survival rates of CRC patients. A potential mechanism for the post-diagnosis benefit of aspirin is the inhibition of EMT and CSC formation which both facilitate tumour progression and metastasis. Aspirin has been demonstrated to suppress the migratory and invasive capacity of lung cancer cell lines by inhibiting EMT. Whilst aspirin has been shown to inhibit platelet-induced EMT in CRC, the direct effects of aspirin on EMT in CRC cell lines has not been established. I hypothesis that aspirin inhibits cell migration, invasion and EMT in CRC which results in a reduction in the CSC population and contributes to the clinical benefit of post-diagnosis aspirin. Using CRC cell lines, I have demonstrated that aspirin treatment inhibits cell migration, invasion, motility and promotes an epithelial phenotype. These results have been confirmed in human organoids and mouse intestinal adenoma in vivo models. Aspirin also promotes a budding phenotype in Apc deficient organoids and reduces expression of stem cell markers in both mouse and human tissue. Aspirin inhibits the mTOR and Wnt signalling pathways in vivo which have the ability to regulate EMT and CSCs although signalling dependency has not been determined. Regardless, aspirin is decreasing the cancer stem cell population and promoting a non-invasive epithelial phenotype which may explain some of the previously described post-diagnosis benefits.

The nucleolus is a multifunctional organelle that, in addition to its primary role in ribosome biogenesis, has emerged as a critical stress sensor and coordinator of stress response. However, the molecular nature of how nucleoli sense stress and coordinate downstream cellular consequence remains poorly understood. NF-κB signalling is a critical regulator of stress response. Many cellular stresses that disrupt nucleolar function also stimulate the NF-κB pathway. However, the role of NF-κB as a downstream effector of nucleolar stress has not yet been examined. Aspirin, a known chemopreventative agent, stimulates the NF-κB pathway to mediate apoptosis but the upstream mechanisms are unclear. In this thesis, I identified a novel nucleolar stress response pathway that culminates in activation of NF-κB signalling, and demonstrated the significance of this nucleolar pathway in the anti-tumour effects of aspirin. Using multiple approaches, I made the novel observations that disruption of the Pol I complex activates the cytoplasmic NF-κB signalling pathway. I show that multiple stress stimuli of NF-κB pathway induce degradation of the crucial Pol I complex component, rDNA transcription initiation factor IA (TIF-IA). I identified the tumour suppressor, p14ARF and the Pol I complex component, upstream binding factor (UBF) as mediators of this degradation. I revealed that inhibition of CDK4 activity lies upstream of UBF/p14ARF-facilitated TIF-IA degradation. Furthermore, using different approaches I show that blocking aspirin/CDK4i-mediated degradation of TIF-IA blocks the effects of these agents on nucleolar morphology and NF-κB signalling. Finally, I show this nucleolar stress response pathway, containing a UBF/p14ARF/TIF-IA axis, is utilized by aspirin to kill colon cancer cells. Taken together, this data presented in this thesis advances understanding of nucleolar stress response, and has therapeutic implications with regard to the anti-tumour effects of aspirin.

Introdução: A interação entre os anticoagulantes e a agregabilidade plaquetária é complexa. Dados laboratoriais prévios mostraram que a dabigatrana aumenta a excreção urinária de metabólito do tromboxano, indicando efeito de ativação de plaquetas. Posteriormente, dados do estudo RELY sugeriram que a dabigatrana 150mg poderia aumentar o risco de infarto do miocárdio em pacientes com fibrilação atrial. Objetivos: Comparar a influência da Dabigatrana e Enoxaparina na agregabilidade plaquetária. Métodos: Estudo prospectivo, intervencionista, realizado em pacientes com doença arterial coronariana (DAC) crônica em uso de aspirina em baixas doses. Os indivíduos foram inicialmente designados para dabigatrana 150mg, 2x/dia, por 5 dias, seguido por um período de washout de 30 dias e depois para exoxaparina 1mg/kg, 2x/dia, por um período adicional de 5 dias. Os testes de função plaquetária foram realizados no início e após cada fase de intervenção, usando agregometria de sangue total p (MEA) (objetivo primário), ELISA para determinação quantitativa de tromboxano B2 (TXB2), Verify Now Aspirin e testes de coagulação (objetivos secundários). Resultados: Em comparação com os valores basais, a dabigatrana aumentou a agregabilidade plaquetária avaliada pelo teste MEA-ASPI (+5U ± 24,1), enquanto a enoxaparina diminuiu a agregabilidade plaquetária (-6U ± 22,2), p=0,012 para a comparação entre os grupos ). O mesmo padrão foi observado usando o ensaio TXB2 (+2pg/mL para dabigatrana, -13pg/mL para enoxaparina, p = 0,011). Não houve diferenças significativas entre os dois grupos em relação aos demais testes. Individualmente, a enoxaparina diminuiu significativamente a agregabilidade plaquetária por TXB2 [33 (16,5 - 95)pg/mL vs. 20 (10-52) pg/mL, respectivamente, p = 0,026), mas não foram observadas diferenças significativas individuais com a dabigatrana em relação aos valores basais. Conclusões: Em relação à agregabilidade plaquetária, há um efeito oposto significativo da dabigatrana (aumento) em comparação com a enoxaparina (diminuição). Individualmente, foi observada uma diminuição significativa na agregabilidade plaquetária apenas com a enoxaparina, quando comparada com valores basais / Background: The interaction between anticoagulants and platelet aggregation is complex. Previous laboratory data have shown that dabigatran increases urinary thromboxane metabolite excretion, indicating platelet-activating effect. Thereafter, data from RELY trial suggested that dabigatran 150mg could enhance the risk of myocardial infarction in atrial fibrillation patients. Objectives: To compare the influence of Dabigatran and Enoxaparin on platelet aggregation. Methods: Prospective, interventional study conducted in chronic coronary artery disease (CAD) patients taking low-dose aspirin. Subjects were assigned initially to dabigatran 150mg bid for 5 days followed by a washout period of 30 days and then to exoxaparin 1mg/kg bid for an additional 5 days period. Platelet function tests were performed at baseline and after each intervention phase using multiple electrode aggregometry (MEA) (primary endpoint), ELISA for plasma quantitative determination of thromboxane B2, Verify Now Aspirin and coagulation tests as secondary endpoints. Results: In comparison with the baseline values, dabigatran increased platelet aggregation evaluated by MEAASPI test (+5U ± 24.1), whereas enoxaparin decreased platelet aggregation (- 6U± 22.2), p=0.012 for the comparison between the groups). The same pattern was observed using theTxB2 assay (+2pg/mL for dabigatran, -13pg/mL for enoxaparin, p=0.011). There were no significant differences between both groups regarding the VerifyNow Aspirin or the other platelet function and coagulation tests utilized. Individually, enoxaparin significantly decreased platelet aggregation by TXB2 [33 (16,5 - 95) pg/mL vs. 20 (10-52) pg/mL, respectivamente, p = 0.026) but no significant differences were observed with dabigatran when individually compared to baseline. Conclusions: Regarding platelet aggregation, there is a significant opposite effect of dabigatran (increase) in comparison with enoxaparin (decrease). Individually, a significant decrease in platelet aggrebability was observed with enoxaparin, but no significant differences were observed with dabigatran

Le diabète non insulino-dépendant de type 2 demeure un problème majeur de santé publique. Cette pathologie associée au vieillissement, à la sédentarisation et à l'obésité induit un taux élevé de complications. Parmi celles-ci, le défaut de cicatrisation et plus particulièrement le syndrome du " pied diabétique " est une des causes majeures de morbidité et de mortalité chez les patients diabétiques. La compréhension de la dérégulation des mécanismes cellulaires et moléculaires du processus cicatriciel chez le diabétique représente un enjeu essentiel pour le développement de nouvelles stratégies thérapeutiques. C'est dans ce contexte que ce travail de thèse a été réalisé. La cicatrisation des plaies est un processus physiopathologique complexe, multifactoriel et dynamique visant à rétablir l'intégrité et la fonctionnalité des tissus lésés. Cette réponse biologique nécessite une orchestration et une communication précise entre les cellules inflammatoires infiltrées et les différentes populations cellulaires des tissus. De manière conventionnelle, on distingue 4 principales phases qui peuvent se chevaucher : une première étape d'hémostase généralement couplée à une phase inflammatoire précoce et arrêtée par une phase de résolution de l'inflammation. Une période de prolifération/ régénération permet la génération du nouveau tissu, et enfin, la phase de remodelage tissulaire permet au tissu de retrouver des caractéristiques d'élasticité et de souplesse proche du tissu original. Les données de la littérature suggèrent que le retard de cicatrisation des personnes diabétiques résulterait de la chronicité de la phase inflammatoire. Notre hypothèse de travail a été de démontrer que cette dérégulation était la conséquence d'un défaut majeur de la phase de résolution de l'inflammation. Notre objectif final a été d'agir sur cette phase pour accélérer le processus cicatriciel. La première étape de ce travail de thèse a consisté à mettre en place un modèle de lésions cutanées par excision chez des souris diabétiques de type 2 (en régime hyper lipidique ou déficientes pour le récepteur de la leptine, db/db). Ce modèle expérimental, combiné à la mise au point d'un dispositif médical innovant nous a permis (i) de recueillir stérilement les cellules et l'exsudat produit au niveau de la lésion cutanée, (ii) d'évaluer les caractéristiques phénotypiques et fonctionnelles des cellules de l'exsudat et (iii) d'évaluer le taux des médiateurs pro- et anti-inflammatoires au cours du temps. L'ensemble de ce travail a pu être réalisé en préservant l'environnement du tissu cicatriciel. Cette première étape a débouché sur le dépôt de 2 brevets en décembre 2011 (FR 2984719 - FR 2984722) suivi de leur extension Européenne l'année suivante. Cette approche expérimentale nous a permis de démontrer que la dérégulation du processus cicatriciel de souris diabétiques de type II était due, à une forte infiltration au niveau de la lésion de polynucléaires neutrophiles, de macrophages inflammatoires M1 et à un défaut d'afflux de macrophages anti-inflammatoires M2. Tout cela était associé à un défaut d'apoptose des cellules inflammatoires et de leur efférocytose. Ces dérégulations signent un défaut de résolution de l'inflammation que nous avons pu valider par la mise en évidence au niveau de l'exsudat inflammatoire et du tissu cicatriciel d'un excès de leucotriène B4 (LTB4) (métabolite de l'acide arachidonique pro-inflammatoire provenant de la voie de la 5-lipoxygénase) au dépend de la lipoxine A4 (LXA4) (métabolite de l'acide arachidonique anti-inflammatoire produit par les voies des 5-LOX et 12/15-LOX). Ces résultats acquis, nous nous sommes attachés à cibler, par une approche pharmacologique originale, la phase de résolution de l'inflammation pour favoriser la fermeture des plaies des souris diabétiques. / Non-insulin dependent type 2 diabetes is a major public health problem due to its prevalence and the high rate of its degenerative complications. Among these problems, healing disorders and more particularly "diabetic foot" ulcers are one of the leading cause of morbidity and mortality of diabetic patients. The understanding of the deregulation of cellular and molecular mechanisms of the wound healing process in diabetic patients is a key issue for the development of new therapeutic strategies. This work was carried out in this context. Wound healing is a physiological multifactorial and dynamic process aiming to the restoration of the integrity and functionality of injured tissue. This complex biological response requires an orchestration and a precise communication between immuno-inflammatory cells and resident cells in the wound tissue. This process can be divided into four distinct but overlapping phases: an inflammatory phase involving the initial stage of hemostasis arrested by a resolution phase of inflammation; a proliferative/regeneration stage and finally a tissue remodeling phase. Data from the literature suggest that the delayed healing in diabetic patient is principally due to chronic inflammation. Our hypothesis was to demonstrate that deregulation was the result of a major impairment of the resolution phase of inflammation. Our ultimate aim was to influence this phase to accelerate the healing process in diabetic mice. The first step of this study was to develop a new cutaneous excisional wound model in type 2 diabetic mice (in High Fat Diet or leptin receptor deficiency mice db/db). Associated with the development of an innovative device, this model allowed us (i) to treat the wound and follow the wound healing evolution (ii), to collect in aseptically condition and over time the secreted exudate, (ii) to evaluate the phenotypic and functional characteristics of exudate cells and to measure the amount of pro-and anti -inflammatory mediators. This first step leads to the publication of two patent applications (filed in December 2011 and published under the references FR 2984719 and FR 2984722). Our experimental approach demonstrate that the impaired wound healing process in type 2 diabetic mice was due to a strong neutrophil and inflammatory macrophage M1 infiltration, and a lack of influx of anti-inflammatory macrophages M2. All this is associated with a failure in the inflammatory cells apoptosis and efferocytosis. These dysregulations sign a default of resolution of inflammation that we have quantified by the measure of excessive leukotriene (LT) B4, (a proinflammatory arachidonic acid (AA) metabolite from the 5-lipoxygenase pathway) in both exudate and scar tissue, at the expense of the lipoxin (LX) A4 (an anti-inflammatory AA metabolite formed from LTA4 by 12/15-LOX). With an original pharmacological approach, we target the resolution of the inflammatory phase to promote wound closure in diabetic mice. For this we have decided to use topical application of acetylsalicylic acid on the wound (AAS-aspirin), 3 days after the establishment of the skin lesion. We demonstrate that aspirin accelerates wound closure in diabetic mice.

京都大学 / 0048 / 新制・課程博士 / 博士(社会健康医学) / 甲第19277号 / 社医博第68号 / 新制||社医||9(附属図書館) / 32279 / 京都大学大学院医学研究科社会健康医学系専攻 / (主査)教授 松原 和夫, 教授 今中 雄一, 教授 髙橋 良輔 / 学位規則第4条第1項該当 / Doctor of Public Health / Kyoto University / DFAM

Introduction Aspirin has been associated with a reduction in mortality in patients diagnosed with colorectal cancer (CRC). A possible mechanism for this is related to the programmed cell death 1 (PD-1) immune checkpoint pathway. Aspirin may have a synergistic effect with PD-1 inhibitors via inhibition of prostaglandin E2 (PGE2) production, which can reverse the ability of tumor cells to evade the immune system. This appears to be strongest in cancers that express PI3 kinase (PI3K) signaling activity, which aspirin downregulates. However, the benefit of pre-diagnosis aspirin use on CRC overall survival (OS) and cancer-specific survival is still controversial, and most studies have been performed in racially homogenous populations. Our study examines the effect of pre-diagnosis aspirin therapy on OS in a racially diverse group of patients with CRC. Methods This is a retrospective chart review of 782 patients diagnosed with CRC from January 2007 to December 2020. Kaplan-Meier curve was created to study the association of aspirin exposure compared to no exposure on OS. In addition, univariate and multivariate binary logistic regression analyses were done to investigate potential predictors of survival. Results Of the 782 patients with CRC, 55.1% were males, 22.2% whites, 58.5% Asians, and 17.7% Pacific-Islanders. Moreover, 38.4% of the patients had a history of aspirin use, 79% of them used it for more than one year. There were more patients with hypertension (HTN), hyperlipidemia (HLD), diabetes mellitus (DM), and chronic kidney disease (CKD) among those with a history of aspirin use. There was no difference in one, three, and five-year OS among aspirin users compared to non-users, p-value = 0.63. Age, grade, and stage were potential predictors of worsened OS. However, treatment with chemotherapy and CKD were potential predictors of worsened OS on univariate analysis only. No significant association was noticed with gender, tumor location, or other associated comorbidities. Conclusion The effect of pre-diagnosis aspirin use on CRC survival is not clear. In this retrospective analysis of a racially diverse population of CRC patients, we found that aspirin use was not associated with improved OS. Therefore, physicians should be careful about using aspirin as adjuvant therapy in CRC patients until high-quality prospective data are available, given the potential associated complications.

The thesis investigated nicotine levels and their effects on hypertensive subjects and whether aspirin could be used in the treatment of hypertension to bring about not only an anti thrombotic effect but reduce the systemic blood pressure especially in those individuals who smoke cigarettes. The study, which also audits the use of aspirin, was conducted in Kuwait and so provides an insight of hypertensive patients very rarely considered in the literature The thesis begins in Chapter One with an extensive literature review which analyses the properties and problems that nicotine causes and its ability to cause hypertensive changes along with its multitude of other events. The physiological and pathological problems caused by nicotine are reviewed on the basis of its chemistry and pharmacological properties using a worldwide perspective rather than just focus on Kuwait. The second Chapter uses extensive analysis of the literature to determine the pharmacological properties of aspirin and its use in cardiovascular disease. The pharmacokinetics and therapeutic effects are presented with emphasis to its inhibitory effects on platelet activation which is central to the development of serious cardiovascular consequences such as stroke and myocardial infarction. The third Chapter returns to consider the literature in detail and why nicotine has specific effects on the cardiovascular system in terms of receptor stimulation and how aspirin may be able to reduce nicotine¿s cardiovascular effects and concludes with the Aims and Objectives of the thesis. The fourth Chapter investigates urinary nicotine levels in smokers from cigarettes available in Kuwait to indicate the actual levels which could be achieved by smokers in this study. This established that the levels would cause pharmacological effects demonstrating also the effects of passive smoking. The number of cigarettes smoked per day has an unpredictable effect on metabolism and urinary output of nicotine. The fifth Chapter is the major investigational section of the thesis and considers if aspirin ability to reduce cardiovascular effects, may be useful in terms of diastolic blood pressure and lipid levels in the 4 blood. The effects were suggestive that aspirin did reduce the blood pressure in hypertensive subjects but was not universal and was limited to those suffering from mild - moderate hypertension. It was determined that aspirin should be sued at the earliest age possible in these patients. The sixth Chapter involved a large scale trial of the effectiveness of aspirin treatment in hypertensive patients over a one year period in Kuwait. This used ambulatory blood pressure measurements to determine the effectiveness of daytime and nightime changes in blood pressure in patients with and without aspirin treatment. The overall conclusion was a reduced relative risk of suffering cardiovascular events in mild to moderate hypertension when aspirin (75mg/day) was administered. Specifically in smokers, aspirin lowers the systolic daytime BP and diastolic nightime BP. To support this work a comprehensive audit is provided of the use of the current use of aspirin in Kuwait hospitals / Cultural Office in the Kuwait Embassy in London; Civil Service Commission of Kuwait; The Assistant Under Secretary for the Drugs and Medical Supplied Affairs