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The Mechanism of Discoidin Domain Receptor 1 Mediated Vascular CalcificationWan, Mark H. 19 March 2013 (has links)
Introduction: Activation of Runt Related Transcription Factor 2 (RUNX2) is required for transdifferentiation of Vascular Smooth Muscle Cells (VSMCs) into a calcifying osteoblast-like phenotype. Our lab showed that deletion of Discoidin Domain Receptor 1 (Ddr1), decreased atherosclerotic vascular calcification in the Ldlr-/- mouse.
Hypothesis: DDR1 regulates RUNX2 activity by affecting microtubule organization during VSMC mediated calcification.
Results: Ddr1-/- VSMCs show reduced RUNX2 activity when compared to Ddr1+/+ VSMCs. Addition of the microtubule-destabilizing agent nocodazole inhibited both RUNX2 activity and nuclear localization in Ddr1+/+ VSMCs. Addition of the microtubule-stabilizing agent taxol rescued RUNX2 nuclear localization in Ddr1-/- VSMCs. Despite this, Taxol was unable to rescue RUNX2 activity as it eliminated activity in both genotypes.
Conclusion: These findings indicate that under osteogenic conditions, Ddr1 deletion impedes the dynamic instability required for the maintenance of microtubule architecture. This prevents RUNX2 nuclear localization and transcriptional activation in VSMCs.
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Articulatory, perceptual, and phonological determinants of accurate production of sOhberg, Alyssa. January 2006 (has links)
Children's speech sound errors may reflect deficits in acoustic-phonetic, articulatory-phonetic, or phonological knowledge of those sounds. The purpose of the current study was to explore the factors believed to contribute to accurate articulation of /s/ in children with typically developing speech. Forty-eight children in their pre-kindergarten or kindergarten year participated. Acousticphonetic knowledge was assessed using a computer game targeting identification of correct and incorrect productions of /s/. Articulatory-phonetic skill was evaluated using maximum repetition tasks and by assessing stimulability for /s/. Phonological knowledge was assessed by examining the acoustic cues used by children to distinguish their productions of /s/ and /theta/. Acoustic-phonetic knowledge and phonological knowledge were each found to explain a small but significant amount of the variance in articulation accuracy. Three different perspectives regarding the relative importance of perceptual and articulatory skills in the development of phonological knowledge are discussed. Clinical implications of the results are considered.
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Sources of inocula of Nosema ceranae and Nosema apis in the European honeybee and their seasonal patterns in QuébecCopley, Tanya January 2011 (has links)
Noseomsis of the European honeybee, Apis mellifera L., is caused by two species of Microsporidia: Nosema ceranae and N. apis. Both species infect primarily the midgut of adult honeybees and have been reported as the third major cause of honeybee losses in Canada. Despite their importance few studies have examined their epidemiology. The current study monitored both species using duplex quantitative Real-Time PCR to determine the seasonal patterns, and potential transmission sources (glands and hive debris) in naturally infected hives from June 2008 to July 2010. Seasonal patterns of both Nosema species differed throughout the years with N. ceranae displacing N. apis. Results also demonstrated the presence of both species in glands suggesting that gland secretions may transmit the parasites. Hive debris and frass also contained spores suggesting that it may transmit the parasites and that bees need not be killed to determine if a hive is infected. / La nosémose des abeilles domestiques, Apis mellifera L., est causée par deux espèces microsporidiennes: Nosema ceranae et N. apis. Elles infectent principalement l'intestin moyen des abeilles et sont la troisième cause de perte d'abeilles au Canada. Malgré ceci, très peu est connu de leurs épidémiologies. Cet étude a examiné les deux espèces en utilisant un duplex de PCR quantitatif pour examiner les variations saisonnières des espèces et divers manières de transmission (glandes et débris de ruche) en des ruches naturellement infectées entre juin 2008 et juillet 2010. Les résultats ont démontré différentes variations saisonnières et que N. ceranae déplace N. apis. Les deux espèces étaient présentes dans les glandes ce qui suggère que leurs sécrétions peuvent transmettre les parasites. Elles étaient aussi présentes dans les débris et les fèces ce qui suggère que ces matières peuvent servir de vecteurs d'infections. De plus, ces résultats proposent une méthode non invasive afin de combattre Ia nosémose des abeilles domestiques car il n'est pas nécessaire de sacrifier des abeilles afin de détecter Ia présence de parasites.
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Low Temperature Mortality of European Red Mite, Panonychus Ulmi (Kock), Winter Eggs and its Ecological Significance.MacPhee, A.W. January 1960 (has links)
The winter eggs of the phytophagous mite Panonychus ulmi (Koch) in Nova Scotia have been found to be killed by cold at the lower extremes of temperature. A more resistant form occurs in the colder areas of New Brunswick and Quebec. For short exposures the mean lethal temperature of overwintering eggs for the susceptible and resistant forms respectively is -24° F. and -35° F. [...]
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Effects of speech perception, vocabulary, and articulation skills on morphology and syntax in children with speech sound disordersMortimer, Jennifer Karen January 2008 (has links)
Although it has been shown that some children with Speech Sound Disorders (SSD) have difficulties in the area of productive morphosyntax, there has been little investigation into the possible source of these problems. Such research may nevertheless shed some light on theoretical questions of morphosyntactic abilities in children with atypical speech and/or language development, as well as suggest avenues for remediation of language weaknesses. The current study examined possible effects of speech perception, vocabulary, and articulation skills on concurrent syntax and longitudinal morphology in a group of seventy-nine children with SSD. Structural Equation Modelling techniques were used to model the relationships among the variables. The rationales for the models were drawn from the literature on children with SSD and also from studies of children with Specific Language Impairment (SLI). The latter were paid particular attention, as some children with SSD may also have SLI, and as morphosyntactic skills in individuals with SLI have been rigorously investigated. It was found that, of the three models examined, an articulation model, in which links were posited from articulation to syntax and from articulation to morphology, demonstrated good fit. Although some of the limitations in morphology and syntax seen in these children could be accounted for in terms of frank articulation errors, other explanations for the association between articulation and morphosyntax were also considered. One possibility was that speech motor skills and morphosyntax were dependent on similar neural substrates that may have been impaired in some of the participants investigated. A second possibility was that, given a finite set of resources devoted to language production, laboured articulation in the children with SSD bled resources from other areas of speech/language processing, and from expressive morphosyntax in particular. Further research, especially studies examining pos / Bien qu'il ait été montré que certains enfants présentant des troubles phonologiques ont aussi des difficultés dans le domaine de la morphosyntaxe productive, peu d'enquêtes ont été faites pour trouver les sources possibles de ces problèmes. Cependant, de telles recherches pourraient éclairer les questions théoriques des habiletés morphosyntaxiques chez les enfants ayant un développement atypique de la parole et/ou du langage, et pourraient aussi suggérer des approches pour remédier aux faiblesses de la langue. La présente étude a examiné les effets possibles des habilités de perception de la parole, du vocabulaire, et de l'articulation sur la syntaxe concurrente et la morphologie longitudinale dans un groupe de soixante-dix-neuf enfants présentant des troubles phonologiques. Les techniques de modèles d'équations structurelles ont été utilisées pour modeler les liens entre les variables. Les exposés raisonnés ont été tirés de la littérature sur les enfants présentant des troubles phonologiques aussi bien que de recherches sur les enfants présentant un trouble primaire (dysphasie) du langage. Une attention toute particulière a été prêtée à ce dernier groupe puisque certains enfants présentant des troubles phonologiques peuvent aussi avoir un trouble primaire du langage et que les habiletés morphosyntaxiques chez les individus présentant un trouble primaire du langage ont été rigoureusement étudiées. On a constaté que, des trois modèles examinés, un modèle d'articulation dans lequel des liens ont été postulés de l'articulation à la syntaxe et de l'articulation à la morphologie se révélait particulièrement approprié. Quoique certaines des limitations en morphologie et syntaxe constatées chez ces enfants puissent provenir de simples erreurs d'articulation, d'autres explications pour le lien entre l'articulation et la morphosyntaxe ont été aussi considérées. Une possibilité serait que les habilet
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Glandular and gastrointestinal (GI) amyloidosis and the chemical nature of GI amyloid in alveolar hydatid cyst infected miceLi, Weihua, 1965- January 1995 (has links)
Patients with systemic amyloidosis frequently show gastrointestinal (GI) tract and adrenal gland involvement with amyloid. However, the evolution of amyloid-related pathological changes in humans is unknown. Conversely, although GI amyloidosis has been described in casein-stimulated mice, the chemical nature of the GI amyloid have not been carried out. Here we report studies on these and related aspects using alveolar hydatid cyst (AHC)-infected mouse model of reactive amyloidosis. Paraffin sections from the adrenal gland, stomach, small and large intestine were obtained from AHC-mice at different time period post-infection (p.i.) and stained with Congo red or immunohistochemically with antibodies against mouse AA amyloid (RAA) or bovine ubiquitin (RABU). The GI-amyloid was purified by column chromatography and analyzed. In the adrenal gland, amyloid deposits were first detected at 4 weeks p.i. in the cortical-medullary junction which then extended into the adrenal parenchyma. In the GI tract, submucosal blood vessels, the first site of amyloid deposition, became amyloidotic at 1 week p.i. With time, the amyloid deposits extended into the lamina propria of the mucosa. Ileum was the most severely affected region in the GI tract. Both RAA and RABU reacted specifically with the GI amyloid. Amyloid was purified by exclusion chromatography in 4M guanidine. The purified amyloid on Western blotting reacted with RAA and on N-terminal amino acid sequence analysis revealed homology with murine serum amyloid A$ sb2$ (SAA$ sb2$) indicating its derivation from SAA$ sb2.$ Both the similarities and the differences between the GI amyloid-related pathological changes in humans and mice are discussed.
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Analysis of human papillomavirus in Schneiderian papillomas as compared to chronic sinusitis and normal nasal mucosaYoskovitch, Adi. January 2001 (has links)
Schneiderian papillomas (SP) are tumors arising from the surface epithelium (Schneiderian epithelium) of the nasal cavity and paranasal sinuses. Evidence points towards a viral etiology, specifically Human papillomavirus (HPV). Although substantial data indicates HPV as a likely etiology, little is known about the role of HPV in benign nasal pathologies or in normal nasal mucosa. Objective. To characterize the role of HPV in SP, chronic sinusitis (CS) and its prevalence in normal nasal mucosa. A case controlled study was undertaken, matching patients with SP to patients with chronic sinusitis (CS). Patients with normal nasal mucosa served as a control group. All patients had their tissues analyzed for the presence of various HPV types using polymerase chain reaction (PCR) coupled with a line blot assay. Results. A total of 168 patients were identified (74 SP, 74 CS, 20 control). Of these, 70 (41.7%) had detectable DNA, and 9/70 (12.9%) had detectable HPV of types 6, 11, and 16. None had detectable HPV type 18. Significant differences were detected in the presence of HPV in CS, SP and control groups, as well as in the presence of low risk versus high-risk types amongst investigation and control groups. Conclusions. Significant differences exist in the distribution of HPV between SP, benign nasal pathologies such as CS and normal nasal mucosa. HPV may play an important role, at least as cofactor, in the development of SP, with types 6, 11 and 16 more pivotal than other types. Line blot assay may provide a useful technique in identifying HPV in SP.
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Reading is in the eye of the beholder: eye movements and early word processes in deaf readers of FrenchBélanger, Nathalie January 2009 (has links)
For the present dissertation, three studies were conducted to investigate various aspects of reading in severely to profoundly deaf individuals who use Quebec Sign Language as their main mode of communication and who were categorized as skilled or less skilled readers. A group of skilled hearing readers also participated so that their results could be compared to existing literature. Two studies investigated the use of orthographic and phonological codes during early French word processing, with a masked primed lexical decision task (Study 1) and with the observation of eye movements (Study 3). The second study served as a bridge between the first and the third studies. The participants' eye movements were recorded to determine their eye movement characteristics, such as their reading speed and the size of their perceptual and word identification spans. The results of the first and third studies converged to show that deaf readers, skilled and less skilled, process orthographic (Studies 1 & 3) and phonological (Study 1) codes very early during word processing. Importantly, skilled and less skilled deaf readers did not differ in the way they encode words relative to the control group of hearing readers. The observation of the participants' eye movements in the second study revealed that reading-level, not hearing status (hearing or deaf), was the main factor determining the characteristics of the participants' eye movements (such as reading speed, size of the word identification span, etc). However, hearing status was a determining factor in the size of the perceptual span of skilled deaf readers, which, unexpectedly, was wider than that of skilled hearing readers. An o / Trois études ont été réalisées afin d'examiner différents aspects de la lecture chez deux groupes de personnes ayant une surdité sévère ou profonde et utilisant la langue des signes québécoise comme mode de communication principal : un groupe de bons lecteurs et un groupe de lecteurs faibles. Un groupe de bons lecteurs entendants a aussi participé aux trois études afin de servir de point de comparaison avec des études existantes. Deux études ont vérifié l'utilisation des codes orthographique et phonologique lors des premiers moments de la reconnaissance des mots, l'une à l'aide d'une tâche de décision lexicale masquée avec amorce (Étude 1) et l'autre à l'aide de l'observation du mouvement des yeux des participants (Étude 3). L'Étude 2 a servi de pont entre la première et la troisième étude. Dans le cadre de cette étude, le mouvement des yeux des participants a été enregistré et plusieurs mesures de bases ont été recueillies, telles que la vitesse de lecture, la largeur de l'empan perceptuel et la largeur de l'empan de reconnaissance des mots. Les résultats de la première et de la troisième étude convergent et montrent que les lecteurs sourds, bons et faibles, utilisent l'information orthographique (Étude 1 et 3) et phonologique (Étude 1) très tôt lors du traitement des mots. Il faut toutefois souligner le fait que les lecteurs sourds (bons et faibles) ne différaient pas du groupe de lecteurs entendants dans la manière dont ils encodent les mots. L'observation du mouvement des yeux des participants lors de la lecture (Étude 2) a révélé que le niveau de lecture, et non le fait d'entendre ou pas, sous-tendait les différence
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Aphasic speech errors : spontaneous and elicited contextsGordon, Jean K. January 2000 (has links)
The goal of the current study was to investigate the retrieval of phonological word forms during the speech production of persons with aphasia, in order to inform models of the structure and function of the phonological lexicon. Using a naturalistic, connected speech task (picture description) and a more structured, single-word production task (picture naming) several characteristics of the target and its phonological 'neighbourhood' were examined, specifically: the target word's frequency of occurrence; the number of words which are phonologically similar to the target (neighbourhood density); and the average frequency of those 'neighbours' (neighbourhood frequency). / To assess the influence of these factors on a target's susceptibility to error, the neighbourhood values of the words produced incorrectly in the picture description task were compared to those of a comparable corpus of correctly produced words from the same speech samples. In the naming task, target susceptibility was assessed by analyzing the error rates on individual stimulus items. The results of both tasks indicated that the lower a target's frequency of occurrence was, and the fewer neighbours it had, the more susceptible it was to error. To assess the impact of the neighbourhood on the outcome of the error, neighbourhood values of the errors produced were compared to those of their targets. In neither task were errors found to differ significantly from their targets in frequency or neighbourhood density. / These results contribute to the literature on lexical access primarily by extending findings of neighbourhood effects in normal speech production to the aphasic population. In doing so, the present study lends support to the basic tenets of the Neighborhood Activation Model (Luce & Pisoni, 1998), and to the notion of the continuity thesis, in which aphasic deficits are hypothesized to reflect quantitative, rather than qualitative, differences from normal processing. Results are also in agreement with previous studies illustrating that aphasic error outcomes are strongly constrained by a number of linguistic factors which also constrain normal error production. Results are interpreted as consistent with an interactive connectionist framework of speech production.
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Permeability to Evans blue and horseradish peroxidase and morphometry on stress fibers in normal and regenerated rat aortic endothelium following segmental balloon injuryCokay, Mehmet Sami January 1990 (has links)
Studies on normal and regenerated rat aortic endothelium at 1, 2, 3 and 4 weeks following segmental balloon denudation injury were carried out to evaluate: (1) the permeability to intravenously injected Evans blue (EB) and horseradish peroxidase (HRP) using en face aortic preparations and (2) the volume density of stress fibers by morphometry using thin section electron microscopy. The results of these studies indicated that: (1) the permeability of the regenerated endothelium to both EB and HRP was identical to normal endothelium at all time points studied and (2) stress fiber volume density significantly increased in regenerated endothelium at 1 week as compared to control, however, returned to and remained at normal value at and after 2 weeks following segmental balloon injury. These results are consistent with the view that structural and functional changes in regenerated vascular endothelium, if present, are transient in nature and the integrity of endothelial monolayer is eventually reestablished during the repair process that follows a single injury.
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