Évaluation des performances énergétiques d'une fenêtre dotée d'un vitrage électrochromique

Les nouvelles technologies utilisées pour la fabrication du verre comme par exemple, les vitrages électrochromiques, ont permis le développement des fenêtres dites dynamiques dans lesquelles les propriétés optiques peuvent être ajustées en fonction des variations de la température et de l’ensoleillement. Ces fenêtres dynamiques permettent une modulation du coefficient de gains solaires (SHGC) en fonction des besoins en chauffage et climatisation ou selon les besoins des occupants. Leurs coûts étant encore relativement élevés, ce type de fenêtres commence à peine à percer le marché commercial. L’objectif de ce mémoire est d'évaluer les performances énergétiques de deux types de fenêtres : une fenêtre à double vitrage (DW) appelée fenêtre de référence, et une fenêtre électrochromique dans les états clair et coloré. Le bilan thermique des fenêtres étudiées est déterminé en fonction des conditions météorologiques pour la ville de Montréal et pour quatre orientations possibles de fenêtre. De plus, trois méthodes de calcul du transfert de chaleur attribuable au rayonnement solaire sont comparées. Les modélisations du transfert de chaleur à l’aide des progiciels Window et Therm montrent qu’il n’y a pas une différence significative entre les coefficients de déperdition thermique des deux types de fenêtre. Les différences entre les fenêtres étant attribuables aux gains solaires, le bilan énergétique sur les fenêtres soumises à des conditions hivernales et estivales montrent que la fenêtre électrochromique permet de réduire les gains de chaleur en été de 1,6 kWh/m2 par jour. Cependant, les performances du vitrage électrochromique en hiver sont moindres par rapport à la fenêtre DW avec une perte d’énergie de 0,75 kWh/m2 par jour comparativement à 0,6 kWh/m2 pour la fenêtre à double vitrage. De plus, les résultats montrent que la contribution du rayonnement diffus est significative sur le bilan énergétique d’une fenêtre

Claudin 1 in Breast Tumorigenesis: Revelation of a Possible Novel “Claudin High” Subset of Breast Cancers

Claudins are the major component of the tight junctions in epithelial cells and as such play a key role in the polarized location of ion channels, receptors, and enzymes to the different membrane domains. In that regard, claudins are necessary for the harmonious development of a functional epithelium. Moreover, defective tight junctions have been associated with the development of neoplastic phenotype in epithelial cells. Breakdown of cell-cell interactions and deregulation of the expression of junctional proteins are therefore believed to be key steps in invasion and metastasis. Several studies suggest that the claudins are major participants in breast tumorigenesis. In this paper, we discuss recent advances in our understanding of the potential role of claudin 1 in breast cancer. We also discuss the significance of a subset of estrogen receptor negative breast cancers which express “high” levels of the claudin 1 protein. We propose that claudin 1 functions both as a tumor suppressor as well as a tumor enhancer/facilitator in breast cancer

Increasing the relative expression of endogenous non-coding Steroid Receptor RNA Activator (SRA) in human breast cancer cells using modified oligonucleotides

Products of the Steroid Receptor RNA Activator gene (SRA1) have the unusual property to modulate the activity of steroid receptors and other transcription factors both at the RNA (SRA) and the protein (SRAP) level. Balance between these two genetically linked entities is controlled by alternative splicing of intron-1, whose retention alters SRAP reading frame. We have previously found that both fully-spliced SRAP-coding and intron-1-containing non-coding SRA RNAs co-exist in breast cancer cell lines. Herein, we report a significant (Student's t-test, P < 0.003) higher SRA–intron-1 relative expression in breast tumors with higher progesterone receptor contents. Using an antisense oligoribonucleotide, we have successfully reprogrammed endogenous SRA splicing and increased SRA RNA–intron-1 relative level in T5 breast cancer cells. This increase is paralleled by significant changes in the expression of genes such as plasminogen urokinase activator and estrogen receptor beta. Estrogen regulation of other genes, including the anti-metastatic NME1 gene, is also altered. Overall, our results suggest that the balance coding/non-coding SRA transcripts not only characterizes particular tumor phenotypes but might also, through regulating the expression of specific genes, be involved in breast tumorigenesis and tumor progression

Age-related differences in 1p and 19q deletions in oligodendrogliomas

BACKGROUND: Recent reports indicate that anaplastic oligodendrogliomas frequently show allelic losses on chromosome arms 1p and 19q, and that these deletions are associated with better chemotherapeutic response and overall patient survival. Because of the diversified genetic makeup of the population and the centralized provincial referral system for brain tumor patients in Manitoba, the epidemiological features of such tumors sometimes differ from the published data acquired from non-community based settings. In this study, we assessed the prevalence of allelic deletions for chromosome arms 1p and 19q in anaplastic and in low-grade oligodendrogliomas in the Manitoba population. METHODS: Loss of heterozygosity (LOH) analysis of brain tumors was carried out using 4 microsatellite markers (D1S508, D1S2734, D19S219 and D19S412) and a PCR based assay. The tumors were consecutively acquired during the period September 1999–March 2001 and a total of 63 tumors were assessed. RESULTS: We found that allelic loss of chromosome 1p and 19q was higher in oligodendrogliomas than in other diffuse gliomas and that for anaplastic oligodendrogliomas, younger patients exhibited significantly more deletions than older patients (>60 years of age). CONCLUSIONS: These studies suggest that age may be a factor in the genetic alterations of oligodendrogliomas. In addition, these studies demonstrate that this assay can easily be carried out in a cost-effective manner in a small tertiary center

Psoriasin, one of several new proteins identified in nasal lavage fluid from allergic and non-allergic individuals using 2-dimensional gel electrophoresis and mass spectrometry

BACKGROUND: Extravasation and luminal entry of plasma occurs continuously in the nose. This process is markedly facilitated in patients with symptomatic allergic rhinitis, resulting in an increased secretion of proteins. Identification of these proteins is an important step in the understanding of the pathological mechanisms in allergic diseases. DNA microarrays have recently made it possible to compare mRNA profiles of lavage fluids from healthy and diseased patients, whereas information on the protein level is still lacking. METHODS: Nasal lavage fluid was collected from 11 patients with symptomatic allergic rhinitis and 11 healthy volunteers. 2-dimensional gel electrophoresis was used to separate proteins in the lavage fluids. Protein spots were picked from the gels and identified using mass spectrometry and database search. Selected proteins were confirmed with western blot. RESULTS: 61 spots were identified, of which 21 were separate proteins. 6 of these proteins (psoriasin, galectin-3, alpha enolase, intersectin-2, Wnt-2B and hypothetical protein MGC33648) had not previously been described in nasal lavage fluids. The levels of psoriasin were markedly down-regulated in allergic individuals. Prolactin-inducible protein was also found to be down-regulated, whereas different fragments of albumin together with Ig gamma 2 chain c region, transthyretin and splice isoform 1 of Wnt-2B were up-regulated among the allergic patients. CONCLUSION: The identification of proteins in nasal lavage fluid with 2-dimensional gelelectrophoresis in combination with mass spectrometry is a novel tool to profile protein expression in allergic rhinitis and it might prove useful in the hunt for new therapeutic targets or diagnostic markers for allergic diseases. Psoriasin is a potent chemotactic factor and its down-regulation during inflammation might be of importance for the outcome of the disease

Real-time PCR complements immunohistochemistry in the determination of HER-2/neu status in breast cancer

BACKGROUND: The clinical benefit of determining the status of HER-2/neu amplification in breast cancer patients is well accepted. Although immunohistochemistry (IHC) is the most frequently used method to assess the over-expression of HER-2 protein, fluorescent in-situ hybridization (FISH) is recognized as the "gold standard" for the determining of HER-2/neu status. The greatest discordance between the two methods occurs among breast tumors that receive an indeterminate IHC score of 2+. More recently, a real-time polymerase chain reaction (PCR) assay using the LightCycler(® )has been developed for quantifying HER-2/neu gene amplification. In this study, we evaluated the sensitivity and specificity of a commercially available LightCycler assay as it compares to FISH. To determine whether this assay provides an accurate alternative for the determination of HER-2/neu status, we focused primarily on tumors that were deemed indeterminate or borderline status by IHC. METHODS: Thirty-nine breast tumors receiving an IHC score of 2+ were evaluated by both FISH and LightCycler(® )technologies in order to determine whether quantitative real-time PCR provides an accurate alternative for the determination of HER-2/neu status. RESULTS: We found a high concordance (92%) between FISH and real-time PCR results. We also observed that 10% of these tumors were positive for gene amplification by both FISH and real-time PCR. CONCLUSION: The data show that the results obtained for the gene amplification of HER-2/neu by real-time PCR on the LightCycler(® )instrument is comparable to results obtained by FISH. These results therefore suggest that real-time PCR analysis, using the LightCycler(®), is a viable alternative to FISH for reassessing breast tumors which receive an IHC score of 2+, and that a combined IHC and real-time PCR approach for the determination of HER-2 status in breast cancer patients may be an effective and efficient strategy

Expression analysis of the mouse S100A7/psoriasin gene in skin inflammation and mammary tumorigenesis

BACKGROUND: The human psoriasin (S100A7) gene has been implicated in inflammation and tumor progression. Implementation of a mouse model would facilitate further investigation of its function, however little is known of the murine psoriasin gene. In this study we have cloned the cDNA and characterized the expression of the potential murine ortholog of human S100A7/psoriasin in skin inflammation and mammary tumorigenesis. METHODS: On the basis of chromosomal location, phylogenetic analysis, amino acid sequence similarity, conservation of a putative Jab1-binding motif, and similarities of the patterns of mouse S100A7/psoriasin gene expression (measured by RT-PCR and in-situ hybridization) with those of human S100A7/psoriasin, we propose that mouse S100A7/psoriasin is the murine ortholog of human psoriasin/S100A7. RESULTS: Although mouse S100A7/psoriasin is poorly conserved relative to other S100 family members, its pattern of expression parallels that of the human psoriasin gene. In murine skin S100A7/psoriasin was significantly upregulated in relation to inflammation. In murine mammary gland expression is also upregulated in mammary tumors, where it is localized to areas of squamous differentiation. This mirrors the context of expression in human tumor types where both squamous and glandular differentiation occur, including cervical and lung carcinomas. Additionally, mouse S100A7/psoriasin possesses a putative Jab1 binding motif that mediates many downstream functions of the human S100A7 gene. CONCLUSION: These observations and results support the hypothesis that the mouse S100A7 gene is structurally and functionally similar to human S100A7 and may offer a relevant model system for studying its normal biological function and putative role in tumor progression