This study tested the hypothesis that administration of deracoxib, a cyclooxygenase-2 specific (COX-2) inhibitor, would result in lower gastric lesion scores than administration of buffered aspirin and gastric lesion scores similar to placebo when administered to healthy dogs for 28 days. Twenty-four, healthy, random source dogs were divided into three groups. Group I received buffered aspirin, 23.6 mg/kg PO q 8h, group II received deracoxib, 1.6 mg/kg PO q 24h and placebo twice daily PO q 8h after deracoxib administration, and group III received placebo PO q 8h. Gastroscopy was performed on days -7, 6, 14, and 28 of treatment. Four regions of the stomach (pylorus, incisura, cardia, and body) were evaluated separately and lesions scored on a scale of 1 (mucosal hemorrhage) to 12 (perforating ulcer) by an observer unaware of which treatments the dogs received. Dogs were observed every 8 hours for vomiting, diarrhea and anorexia. Feces were scored from 1-5 (scores <4 were considered diarrhea). Lesion scores for each group, at each location, and total scores, at each time period, were evaluated for the effects of time and treatment using a Kruskal-Wallis test. Total dog days of vomiting and dog days of diarrhea in each group were compared using a Wilcoxon rank sums test. Significance was determined at p<0.05. Significantly higher median total gastric lesion scores were found in the aspirin group compared to the deracoxib or placebo groups on days 6, 14, and 28. There were no significant differences in median total gastric lesion scores between the deracoxib or placebo groups at any time during the study. There was no location effect on gastric lesion scores and there was no significant change in gastric lesion scores over time in any of the groups during treatment. Significantly more dog-days of vomiting occurred in the aspirin group as compared to the deracoxib group. No significant differences were found between groups for dog-days of diarrhea. In this study, the administration of deracoxib to healthy dogs resulted in significantly lower gastric lesion scores compared to dogs receiving aspirin and lesion scores similar to those receiving placebo. / Master of Science

Equine gastric glandular mucosal ulceration can have a prevalence of 58%, yet its etiology is poorly understood. In man Helicobacter pylori is the most common cause of gastritis and peptic ulcer disease. Helicobacter is uniquely able to colonize the stomach, via the action of cytoplasmic urease. Different Helicobacter species have been isolated from many mammals but none has yet been cultured from the horse. Three tests used to identify human Helicobacter infection were applied to the horse. Test 1: PCR amplification of Helicobacter specific DNA, n=12. Test 2: the Pyloritek™ rapid urease test (RUT), n=15. Test 3: the 13C-urea blood test, n=8. Gastroscopy and antral biopsy was performed in all horses. All horses demonstrated the presence of Helicobacter specific gene material by PCR. Biopsy specimens from 7/15 horses were urease positive by RUT. Significant 13C enrichment of the body CO2 pool was found in all horses after intragastric administration 13C-urea (p<0.05). As Helicobacter is currently the only known gastric urease positive microorganism, the demonstration of this activity in horses positive by PCR strongly supports the presence of an equine gastric Helicobacter species. Variations of 13C-urea blood test were further examined and a single protocol was found to be most applicable. As the horse is a hind gut fermenter, the effect of cecal urease on the test was examined by laparoscopic intracecal administration of 13C-urea. Significant cecal urease activity was demonstrated however the timing of peak 13C enrichment may limit any effect on the gastric test to 90 minutes onwards. / Master of Science

Venous leg ulceration has a high recurrence rate. Patients with healed or frequently recurring venous ulceration are required to perform self-care behaviours to prevent recurrence or promote healing, but many find these difficult to perform. Bandura’s self-efficacy theory is a widely used and robust behaviour change model and underpins many interventions designed to promote self-care in a variety of chronic conditions. By identifying areas where patients may experience difficulty in performing self-care, interventions can be developed to strengthen their self-efficacy beliefs in performing these activities successfully. There are currently a variety of self-efficacy scales available to measure self-efficacy in a variety of conditions; but not a disease-specific scale for use with venous ulcer patients. The aim of this study, therefore, was to develop a disease-specific, patient-focused self-efficacy scale for patients with healed venous leg ulceration. Phase 1 consisted of a qualitative design and used focus group methodology to generate an item pool for potential inclusion into the scale from the patients’ perspective. In phase 2, factor analysis using equamax orthogonal rotation methods was used to reduce the items from 60 to 30, resulting in 5 major domains: general self-care; daily self-care tasks; normal living; developing expertise and avoiding trauma. Preliminary reliability studies indicated that the developed scale, VeLUSET© has good internal consistency, with an overall Cronbach alpha of .929 and a strong test-re-test reliability. Furthermore, correlation with the General Self-Efficacy Scale demonstrated a strong positive relationship between the two scales. These results indicate that the VeLUSET©, although still in the early validation stages, is a reliable instrument to measure venous leg ulcer patients’ self-efficacy in performing self-care tasks within clinical practice. The development of this disease-specific tool has now filled a gap in the research on managing patients with healed venous leg ulceration.

Diabetic foot ulceration (DFU) is a known major complication of diabetes mellitus which contributes to lower extremities amputation. This study aimed to investigate the use of interventional devices either as a preventative or therapeutic strategy to improve clinical management of this pathology, as well as investigating the impaired function of endothelial progenitor cells in the diabetic condition. The first element targeted plantar callus formation among diabetic neuropathic (NRP) patients through the use of a SurroSenseRxTM biofeedback device. Reducing foot pressure with improved walking strategy in the 6 months study in diabetic neuropathy patients (n=20) appeared to minimise the size of non-ulcerative plantar callus (p < 0.05), potentially reducing future ulcer recurrence. The 2nd study focused on the use of a GekoTM electrical stimulation device to enhance DFU healing in 24 patients. Wounds were characterised as being neuroischaemic (NRI) or neuropathic (NRP) based on standard parameters adopted in the Manchester diabetes clinic. The device was worn by 11 intervention subjects and compared to 13 controls without any electrical stimulus. Results suggested healing and wound closure have potentially increased in participants with electrical stimulation. In addition, Neuropathy Disability Score (NDS) was improved among intervention patients compared to control (p < 0.0001). The 3rd, in vitro and mechanistic study focuses on the outgrowth of endothelial cells (OECs), abnormal angiogenic responses and inflammatory microenvironment which could contribute to impaired wound healing in diabetic patients. OECs were isolated from diabetic patients and healthy controls (HCs), characterised by immunohistochemistry and Polymerase Chain Reaction (PCR). The functions of the three OEC groups from NRI, NRP diabetic patients and healthy controls respectively were compared using in vitro proliferation, transwell migration and wound healing scratch assays, together with matrigel tube formation assays. Scratch assays showed 100% closure in HCs over 24 hours, while 86.6% closure was apparent in NRI vs 38.1% in NRP. Seahorse mitochondrial stress test was conducted and demonstrated mitochondrial dysfunction in NRP vs NRI vs HCs (p < 0.05). Western blot analysis showed a lack of ERK phosphorylation by NRP OECs and an up-regulation of plasma inflammatory cytokines (TNFa and IL-6) in diabetic samples vs HC (p < 0.0001), while the angiogenic factors ang-2, FGF-2, VEGF-D, HGF and IL-8, and nitric oxide bioavailability were all significantly reduced in diabetic samples vs HC (p < 0.05). The functional defects of the diabetic OECs were partially restored through glycomimetic (synthesis compounds for endothelial damage protection) treatment (p < 0.05). In summary, this study has highlighted areas worthy of future development both in terms of preventative and therapeutic strategies. With improvements in digital technology and the need to empower patients to take responsibility of their health and well-being as well as greater understanding of the cellular and molecular biological repair processes that may be exploited, there may be potentials to reduce the risk of future ulceration among patients using these novel approaches in the future.

The purpose of this observational cross-sectional study was to assess the oral health of children between the ages of 6 to 18 with neutropenia attending the Marrow Failure and Myelodysplasia Program at The Hospital for Sick Children and compare the results to healthy control patients attending the Children’s Clinic, Faculty of Dentistry, University of Toronto. Fifteen patients with neutropenia and 26 healthy controls participated in this study. Patients with neutropenia reported an increased incidence of mouth sores and bleeding gums while brushing. However, clinical examination showed no statistical differences in the presence of ulcerations, gingival recession, tooth mobility, gingival inflammation or plaque and calculus levels. The dmft/t and DMFT/T scores were lower for the group with neutropenia, but only the dmft/t score was significant. This data suggests that patients with neutropenia that are being treated by a haematologist do not experience any more severe oral problems than healthy dental patients.

The purpose of this observational cross-sectional study was to assess the oral health of children between the ages of 6 to 18 with neutropenia attending the Marrow Failure and Myelodysplasia Program at The Hospital for Sick Children and compare the results to healthy control patients attending the Children’s Clinic, Faculty of Dentistry, University of Toronto. Fifteen patients with neutropenia and 26 healthy controls participated in this study. Patients with neutropenia reported an increased incidence of mouth sores and bleeding gums while brushing. However, clinical examination showed no statistical differences in the presence of ulcerations, gingival recession, tooth mobility, gingival inflammation or plaque and calculus levels. The dmft/t and DMFT/T scores were lower for the group with neutropenia, but only the dmft/t score was significant. This data suggests that patients with neutropenia that are being treated by a haematologist do not experience any more severe oral problems than healthy dental patients.

La sclérodermie (SSc) est une pathologie grave caractérisée par une atteinte microvasculaire combinée à une fibrose cutanée. Au niveau des extrémités, ce phénomène provoque des ulcères digitaux (UD) particulièrement douloureux et qui contribuent à diminuer la qualité de vie des patients atteints. La cicatrisation des UD est difficile et souvent de mauvais pronostic avec d’importants risques d’infection voire d’amputation. A ce jour, les injections intraveineuses d’iloprost, un analogue de la prostacycline, sont le seul traitement reconnu mais leur utilisation entraîne des effets secondaires et requiert une hospitalisation. Le treprostinil, un autre analogue de la prostacycline, est susceptible d’induire une importante vasorelaxation ce qui en fait une molécule d’intérêt majeur dans la prise en charge des UD. La sclérodermie est une pathologie complexe et aucun modèle animal ne présente l’ensemble de ses caractéristiques physiopathologiques. Parmi les modèles existants nous avons sélectionnés deux modèles murins (HOCL et uPAR-/-) récemment décrits comme étant prometteurs pour développer de nouvelles approches thérapeutiques dans la prise en charge des symptômes de la SSc.L’objectif de cette étude est d’évaluer l’iontophorèse de treprostinil comme stratégie locale pour induire une accélération de la cicatrisation d’ulcères provoqués sur modèles de SSc. Brièvement, une lésion a été réalisée par excision de peau au niveau du dos de souris. Les animaux ont été répartis aléatoirement dans trois groupes : « témoin », « contrôle » et « treprostinil » et les plaies ont été suivies jusqu’à cicatrisation complète.Les animaux traités par iontophorèse de treprostinil présentent une cicatrisation accélérée. Ces résultats ont été observés pour les deux modèles de SSc. L’effet le plus important a été mesuré au cours de la phase précoce de la cicatrisation.Cette étude est la première a démontré que la iontophorèse de treprostinil s’avère être une piste prometteuse dans la prise en charge thérapeutique des UD chez les patients atteints de SSc. D’autres études précliniques devront être menées pour mieux comprendre les mécanismes et une étude clinique devra confirmer ce résultat sur des patients. / Systemic Sclerosis (SSc) is a serious disease affecting the skin microcirculation and characterized by fibrosis. Digital ulcers (DU) are the principal manifestation of this microvascular dysfunction in the extremities. DUs are frequent, painful, can cause functional impairment and have a major negative impact on the quality of life. Wound healing of DU is delayed and this can result in gangrene and amputation. To date, intravenous prostacyclin analogues (iloprost) are the only approved treatment for active SSc-related DU but their use is limited by serious vasodilation-induced side effects and usually requires hospitalization. Treprostinil is a prostacyclin receptor agonist that induces vascular relaxation and is used to treat advanced digital ischemia. Treprostinil is a very interesting candidate to enhance wound healing of ulcers in fibrotic skin. Scleroderma is a complex pathology and there is none existing animal model that can encompass all aspects of the disease related to fibrosis and vasculopathy. Among existing models, we selected two murin models (HOCL and uPAR-/-) that were recently described as promising tool to study SSc-related vasculopathy and fibrosis such as digital ulcers.The main objective of this study was to evaluate the therapeutic effect of topical administration of treprostinil on wound healing in two different preclinical models of SSc. Briefly, cutaneous excisional wounds were induced on mice. Animals were randomized into 3 sub-groups according the treatment to be administered: “sham”, “control” and “treprostinil” and wound process was followed until full recovery.Treprostinil iontophoretically-administered induced a significant acceleration in wound healing process in both models of SSc. The most significant effect was observed during the early phase of the healing process.This study demonstrated that iontophoresis of treprostinil could be proposed as a local therapeutic strategy to SSc patients with digital ulcers. Further pre-clinical studies should be realized to explore the underlying pharmacological and electrical mechanisms involved and clinical study should be started soon to assess the potential effect on SSc-related ulcers.

No / High compression therapy, whether with bandage systems or hosiery, is the accepted treatment of lower limb venous ulceration. Compression has not only been shown to improve healing, it has been demonstrated to reduce oedema and improve tissue oxygen levels (Stacey et al, 1990), reversing some of the changes associated with chronic venous insufficiency (Vandongen and Stacey, 2000). The introduction of multilayer high compression bandage systems in the late 1980s, and subsequent improvements in bandage textiles and design, have undoubtedly improved outcomes for many patients. However, compression alone does not address the underlying pathology of venous ulceration, chronic venous insufficiency (CVI), and without treatment CVI continues to cause skin damage and increases the risk of recurrent ulceration. In 1999, Nelzen emphasised that compression treatment has been used since the days of Hippocrates and yet has not solved the problem of leg ulceration (Nelzen, 1999).

Twenty-four healthy, mixed breed dogs were divided into four groups. Group I received a placebo PO BID, group II received an average 16.5 (range, 15.1-17.8) mg/kg buffered aspirin PO BID, group III received an average 2.2 (range, 2.0-2.4) mg/kg carprofen PO BID, and group IV received an average 12.8 (range, 11.7-13.8) mg/kg etodolac PO QD (with a placebo in the P.M.). All treatments continued for 28 consecutive days. Gastroduodenal endoscopy was performed on days – 9, 0, 5, 14 and 28. Multiple gastric biopsies were obtained endoscopically on day – 9 to determine each dog's Helicobacter spp. status. Five areas, consisting of four regions in the stomach and one in the proximal duodenum, were evaluated endoscopically, and each was assigned a score from 1 to 11 based on qualitative assessment of submucosal hemorrhage, erosion, or ulceration. These scores for each region were then summed to give a total score for each endoscopic evaluation. Erosions and submucosal hemorrhages were seen in all dogs receiving aspirin. Only minor gastric lesions were observed in the carprofen, etodolac, and control groups. No adverse clinical signs were noted in any dog given any treatment during the course of the study. There was no predilection site for lesion development in any group. Median total score on days 0, 5, 14, and 28 were as follows: group I, 5.0, 5.0, 5.0, 5.0; group II, 5.0, 27.0, 26.0, 27.5; group III, 5.0, 5.0, 6.0, 5.0; group IV, 5.0, 7.0, 5.0, 5.0, respectively. There was no significant difference between dogs receiving carprofen, etodolac, or placebo. The administration of carprofen, etodolac, or placebo to healthy dogs resulted in significantly less gastroduodenal lesion development than in dogs receiving buffered aspirin. Thirty healthy, random source, dogs were evaluated to determine the prevalence of Helicobacter spp., and to compare the ‘Campylobacter-like organism’ test (CLOtest®) to histopathologic identification of Helicobacter spp. organisms. Gastric mucosal biopsies from each of four gastric regions (cardia, pyloric antrum, greater curvature, and angularis incisura) were obtained endoscopically for use in the CLOtest® and for histopathologic evaluation. Twenty-seven of 30 dogs (90%) were positive for spiral bacteria suspected to be Helicobacter spp. by histopathologic evaluation in at least one of the four gastric regions. Three dogs (10%) were negative for Helicobacter spp. in all gastric regions by histopathologic evaluation. The CLOtest® was found to have a sensitivity, specificity, and positive predictive value of 84%, 81%, and 92%, respectively, when compared to histopathologic evaluation. When only the angularis incisura was evaluated, the sensitivity, specificity, and positive predictive value increased to 92%, 94%, and 96%, respectively. The angularis incisura had the highest, whereas the pyloric antrum had the lowest, prevalence of positive test results when compared to dogs determined to be overall Helicobacter spp. positive (histopathologic positive in at least one gastric region). The results of this study suggest the prevalence of Helicobacter spp. in apparently healthy dogs is high. For accurate and economical detection of Helicobacter spp. in a dog undergoing upper gastrointestinal endoscopy, a tissue sample should be taken from the angularis incisura for CLOtest® sampling. / Master of Science

L'obésité et le diabète sont associés à des complications cutanées, en particulier des fonctions dermiques impliquées dans le maintien de la résistance mécanique de la peau. Cependant, les mécanismes par lesquels l'obésité provoque la fragilité du tissu cutané sont peu étudiés. Notre travail consistait à évaluer les effets d'un régime hypercalorique sur la microcirculation cutanée et les conséquences sur le développement de lésions cutanées. Les études ont été réalisées chez des souris C57Bl6/J développant une obésité induite par une alimentation enrichie en graisse et en sucre pendant 2, 4, 12 et 20 semaines. Les propriétés de la microcirculation cutanée sont évaluées par les variations du flux sanguin en réponse : 1) à l'acétylcholine afin de déterminer la vasodilatation endothélium-dépendante, 2) au nitroprussiate de sodium afin de déterminer la vasodilatation endothélium-indépendante, 3) à l'application de la pression locale afin de déterminer la vasodilatation induite par la pression (PIV). Ces études sont complétées par des explorations métaboliques (IPGTT, IPITT), morphologiques, immuno-histologiques et biochimiques pour caractériser les quatre modèles. Enfin, chaque modèle a été testé pour l'incidence d'ulcère de pression par l'application d'une pression unique de 85 mmHg. Dans ce travail de thèse, nous avons mis en évidence de nombreux mécanismes de compensation accompagnant l'évolution de l'obésité et qui permettent de maintenir les fonctions vasculaires intactes et permettent de s'adapter à l'environnement inflammatoire induit par l'alimentation hypercalorique. La PIV est un outil de diagnostic nous permettant d'évaluer l'intégrité de la fonction neurovasculaire et prédire l'incidence de lésions cutanées / Obesity and diabetes are associated to skin pathophysiology, particularly the dermal functions involved in maintaining the skin’s mechanical strength. The underlying mechanisms in pressure ulcer during obesity remain unclear. In this study we evaluated the effects of a hypercaloric diet on the cutaneous microcirculation and its consequences on pressure sores. C59Bl6/J mice were fed a high fat and high sugar diet during 2, 4, 12 and 20 weeks. Microvascular properties were assessed by measuring the skin blood flow variations in response to 1) acetylcholine in order to determine the endothelium-dependent vasodilation, 2) sodium nitroprusside in order to determine the endothelium-independent vasodilation, 3) local pressure application in order to determine the pressure-induced vasodilation (PIV). Each model was characterized for metabolic assessment (IPGTT, IPITT), hisological, immune-histological and biochemical measurements. Finally, each model was tested for pressure ulcer incidence with a 85 mmHg pressure application on skin layers. In this study, we found that obesity is a pathology in constant evolution that is associated with many compensatory mechanisms for maintaining vascular functions and for the adaptation of the skin tissue to an inflammatory environment induced by a hypercaloric diet. PIV has become a useful tool for pressure ulcer prediction