Publications by authors named "James Poon"

Topographical cues are known to influence cell organization both in native tissues and . In the trachea, the matrix beneath the epithelial lining is composed of collagen fibres that run along the long axis of the airway. Previous studies have shown that grooved topography can induce morphological and cytoskeletal alignment in epithelial cell lines.

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There is a need to establish in vitro lung alveolar epithelial culture models to better understand the fundamental biological mechanisms that drive lung diseases. While primary alveolar epithelial cells (AEC) are a useful option to study mature lung biology, they have limited utility in vitro. Cells that survive demonstrate limited proliferative capacity and loss of phenotype over the first 3-5 days in traditional culture conditions.

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Germline stem cells in the Drosophila ovary are maintained by a somatic niche. The niche is structurally and functionally complex and contains four cell types, the escort, cap, and terminal filament cells and the newly identified transition cell. We find that the large Maf transcription factor Traffic jam (Tj) is essential for determining niche cell fates and architecture, enabling each niche in the ovary to support a normal complement of 2-3 germline stem cells.

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The epithelium is one of the most important tissue types in the body and the specific organization of the epithelial cells in these tissues is important for achieving appropriate function. Since many tissues contain an epithelial component, engineering functional epithelium and understanding the factors that control epithelial maturation and organization are important for generating whole artificial organ replacements. Furthermore, disruption of the cellular organization leads to tissue malfunction and disease; therefore, engineered epithelium could provide a valuable in vitro model to study disease phenotypes.

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Following conjugation with glutathione, xenobiotics are converted into cysteinylglycine conjugates, cysteine conjugates, and finally, mercapturic acids. The structural factors determining the activities of dipeptidases for the metabolism of toxicologically-relevant cysteinylglycine conjugates are not well understood. We purified porcine kidney cortex membrane dipeptidase (MDP) to homogeneity, via phosphatidylinositol-specific phospholipase C-mediated cleavage of the protein's membrane anchor and cilastatin affinity chromatography.

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