48 research outputs found
Microarray and pathway analysis reveals decreased CDC25A and increased CDC42 associated with slow growth of BCL2 overexpressing immortalized breast cell line
Bcl-2 is an anti-apoptotic protein that is frequently overex-pressed in cancer cells but its role in
carcinogenesis is not clear. We are interested in how Bcl-2 expression affects non-cancerous breast
cells and its role in the cell cycle. We prepared an MCF10A breast epithelial cell line that stably
overexpressed Bcl-2. We analyzed the cells by flow cytometry after synchronization, and used cDNA
microarrays with quantitative reverse-transcription PCR (qRTPCR) to determine differences in gene
expression. The microarray data was subjected to two pathway analysis tools, parametric analysis of
gene set enrichment (PAGE) and ingenuity pathway analysis (IPA), and western analysis was carried
out to determine the correlation between mRNA and protein levels. The MCF10A/Bcl-2 cells
exhibited a slow-growth phenotype compared to control MCF10A/Neo cells that we attributed to a
slowing of the G1-S cell cycle transition. A total of 363 genes were differentially expressed by at
least two-fold, 307 upregulated and 56 downregulated. PAGE identified 22 significantly changed
gene sets. The highest ranked network of genes identified by IPA contained 24 genes. Genes that
were chosen for further analysis were confirmed by qRT-PCR, however, the western analysis did
not always confirm differential expression of the proteins. Downregulation of the phosphatase
CDC25A could solely be responsible for the slow growth pheno-type in MCF10A/Bcl-2 cells.
Increased levels of GTPase Cdc42 could be adding to this effect. PAGE and IPA are valuable tools
for microarray analysis, but protein expression results do not always follow mRNA expression
results. Originally published Cell Cycle, Vol. 7, No. 19, Oct. 200
The relationship between the perception of distributed leadership in secondary schools and teachers' and teacher leaders' job satisfaction and organizational commitment
This study investigates the relation between distributed leadership, the cohesion of the leadership team, participative decision-making, context variables, and the organizational commitment and job satisfaction of teachers and teacher leaders. A questionnaire was administered to teachers and teacher leaders (n=1770) from 46 large secondary schools. Multiple regression analyses and path analyses revealed that the study variables explained significant variance in organizational commitment. The degree of explained variance for job satisfaction was considerably lower compared to organizational commitment. Most striking was that the cohesion of the leadership team and the amount of leadership support was strongly related to organizational commitment, and indirectly to job satisfaction. Decentralization of leadership functions was weakly related to organizational commitment and job satisfaction
Pricing Health Services Verification of a Monopoly Pricing Model for Dentistry
A model of monopoly with constant marginal costs is used to derive a price function for dental services. The implications of the model are tested using data on individual practitioners from a national survey. The implications of the model are met by the data, providing strong evidence of the appropriateness of the monopoly model to analyses of the market for dental services. The empirical evidence also provides substantial information on the determinants of dental fees.
The relationship of cell size, intercellular space, and specific gravity to Bruise depth in potatoes
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Dynamic scheduling of network updates
We present Dionysus, a system for fast, consistent network updates in software-defined networks. Dionysus encodes as a graph the consistency-related dependencies among updates at individual switches, and it then dynamically schedules these updates based on runtime differences in the update speeds of different switches. This dynamic scheduling is the key to its speed; prior update methods are slow because they pre-determine a schedule, which does not adapt to runtime conditions. Testbed experiments and data-driven simulations show that Dionysus improves the median update speed by 53--88% in both wide area and data center networks compared to prior methods