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25 results on '"Dziak, Ewa"'

7. bFGF-induced transdifferentiation of RPE to neuronal progenitors is regulated by the mechanical properties of the substratum

Author

Opas, Michal and Dziak, Ewa

Subjects
Fibroblasts -- Research, Epithelium -- Research, Retina -- Research, Biological sciences
Abstract

Basic fibroblast growth factor (bFGF) stimulation of N-CAM negative retinal pigment epithelium (RPE) yields N-CAM-positive neural retina through transdifferentiation. The fate determination of presumptive RPE is influenced by the growth substrata properties. Hydrated basement membrane gels and layers of stationary basement membrane proteins are used in the study. The presumptive RPE fate is determined by the bFGF.

Published
1994

11. LPS-induced depolymerization of cytoskeleton and its role in TNF-[Alpha] production by rat pneumocytes

Author

ISOWA, NORITAKA, XAVIER, ALEXANDRE M., DZIAK, EWA, OPAS, MICHAL, MCRITCHIE, DONNA I., SLUTSKY, ARTHUR S., KESHAVJEE, SHAF H., and LIU, MINGYAO

Subjects
Tumor necrosis factor -- Research, Cytokines -- Research, Endotoxins -- Research, Cytoplasmic filaments -- Research, Microtubules -- Research, Biological sciences
Abstract

Isowa, Noritaka, Alexandre M. Xavier, Ewa Dziak, Michal Opas, Donna I. McRitchie, Arthur S. Slutsky, Shaf H. Keshavjee, and Mingyao Liu. LPS-induced depolymerization of cytoskeleton and its role in TNF-[Alpha] production by rat pneumocytes. Am. J. Physiol. 277 (Lung Cell. Mol. Physiol. 21): L606-L615, 1999.--Lipopolysaccharide (LIPS) polymerizes microfilaments and microtubules in macrophages and monocytes. Disrupting microfilaments or microtubules with cytochalasin D (CytoD) or colchicine can suppress LPS-induced tumor necrosis factor-[Alpha] (TNF-[Alpha]) gene expression and protein production from these cells. We have recently demonstrated that primary cultured rat alveolar epithelial cells can produce TNF-[Alpha] on LPS stimulation. In the present study, we found that the LPS-induced increase in TNF-[Alpha] mRNA level and protein production in alveolar epithelial cells was not inhibited by CytoD or colchicine (1 nM to 10 [micro]M). In fact, LPS-induced TNF-[Alpha] production was further enhanced by CytoD (1-10 [micro]M) and inhibited by jasplakinolide, a polymerizing agent for microfilaments. Immunofluorescent staining and confocal microscopy showed that LPS (10 [micro]g/ml) depolymerized microfilaments and microtubules within 15 min, which was prolonged until 24 h for microfilaments. These results suggest that the effects of LPS on the cytoskeleton and the role of the cytoskeleton in mediating TNF-[Alpha] production in alveolar epithelial cells are opposite to those in immune cells. This disparity may reflect the different roles between nonimmune and immune cells in host defense. tumor necrosis factor-[Alpha]; cytokines; lipopolysaccharide; microfilament; microtubule

Published
1999

17. Calreticulin Affects β-Catenin-associated Pathways

Author

Fadel, Marc P., primary, Szewczenko-Pawlikowski, Malgorzata, additional, Leclerc, Pierre, additional, Dziak, Ewa, additional, Symonds, J. Matthew, additional, Blaschuk, Orest, additional, Michalak, Marek, additional, and Opas, Michal, additional

Published
2001
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20. Intracellular pH and pCa Measurement.

Author

Walker, John M., Paddock, Stephen W., Opas, Michal, and Dziak, Ewa

Abstract

Recent improvements in confocal technology permit the use of a confocal microscope as an effective tool to both measure concentration and visualize distribution of several ions. Effective discrimination against out-of-focus information in the confocal microscope permits for mapping of ion distribution at the subcellular level (1). To generate such a map with any degree of accuracy it is necessary to compensate for inherent cellular inhomogeneities in optical path, probe distribution, etc. To do so ratiometric measurements are usually employed (2,3). Fluorescence ratiometry takes advantage of a differential spectral sensitivity of a ratio probe to the measured parameter (e.g., ion concentration). Whereas fluorescent properties of the ratio probe at one wavelength are parameter sensitive in one manner, the emission (or excitation) of the probe at a distinct, well-separated wavelength must be either parameter insensitive, inversely sensitive, or exhibit a different sensitivity profile. Emission intensities for the two wavelengths are then divided by each other and thus the resulting ratio becomes normalized for inhomogeneities in probe distribution and concentration and in the system geometry. To obtain meaningful data the ratio values must be calibrated against a standard, which usually is a graded change in the parameter. Modern day confocal microscopy depends on lasers as light sources which causes a severe limitation in number of wavelengths available for fluorochrome excitation. Several H+-sensitive fluorochromes are excited at wavelengths close to those emitted by standard lasers, however, this is not the case with Ca2+-sensitive fluorochromes (4). [ABSTRACT FROM AUTHOR]

Published
1999
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