Browsing by Subject "epithelial cells"

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    Effect of carbon nanotubes on transepithelial resistance in barrier epithelial cells
    (Office of the Vice Chancellor for Research, 2012-04-13) Lewis, Shanta; Blazer-Yost, Bonnie L.; Petrache, Horia I.; Roark, Torri
    The burgeoning of the nanotechnology industry has revolutionized engineering, medicine and the fashion industry amongst many other technologies. The arrays of products that are synthesized from nanomaterials include high definition TV and computer screens, artificial organs, as well as antibacterial food containers. With these novel applications there is a paralleled concern of the negative implications of nano-material contamination in our environment and food chains. We are interested in carbon nanotubes because they are the most abundantly occurring nanoparticles that are found in the workplace. We have recently conducted studies in barrier epithelial cells to show that long single-wall and multi-wall carbon nanotubes (CNTs) caused a decrease in the transepithelial electrical resistance, a measure of the barrier function ,of renal principal cells at very low concentrations (0.4 ng/cm2- 4 g/cm2). These results suggested that nanoparticles may also cause an effect on other barrier epithelial cells such as those lining the human digestive and respiratory tracks. After 48 hours of CNT exposure, to airway and colon cell lines, Calu-3 and t84 respectively, the calculated resistances were approximately half of the control monolayers’, indicating that the barrier function of the tissue had been compromised, while the cellular monolayer remained intact. We sought to determine the mechanism of action of the nanoparticles, by investigating the interaction of CNTs with model lipid membranes using a bilayer clamp amplifier. Measurements showed that the presence of nanoparticles caused transient disruptions in lipid membranes made of phosphatidylcholine lipids. Nanotubes also caused transient interruptions in the current allowed by the ion channel reporter (gramicidin A). These results began to elucidate the mode of action of the particles and indicated that it is important to develop a complete understanding of how nanoparticles interact with cells if we are to safeguard against changes that these materials will cause in vivo.
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    THE EFFECTS OF TOBACCO TREATED PORPHYROMONAS GINGIVALIS ON HUMAN EPITHELIAL CELLS
    (Office of the Vice Chancellor for Research, 2012-04-13) Tursunova, Roziya H.; Al-Shibani, Nouf; Windsor, L. Jack; Gregory, Richard L.
    Bacteria and tobacco are risk factors for periodontal diseases. Bacteria-host interactions play a critical role in disease development and progression. The effects of tobacco-treated bacteria such as Porphyromonas gingivalis on epithelial cells have not yet been examined. Therefore, P. gingivalis were treated with different tobacco products (nicotine, cigarette smoke conden-sate (CSC), and dissolvable smokeless tobacco (DST) strips) to determine the effects that they have on epithelial cells. P. gingivalis were grown with or without the products for 24 hours at 37◦C. The cells were separated from the supernatant, washed with 0.9% NaCl and incubated at 60◦C to kill the bacte-ria. Protein assays was performed to determine the protein concentration in the cell pellets and supernatants. Lactate dehydrogenase (LDH) assays are being used to measure the cytotoxicity of the cells and supernatants on epi-thelial cells in a dose dependent manner. Non-toxic amounts of the cell pel-lets and supernatants will be used to treat epithelial cells for 72 hours and the media analyzed by cytokine/growth factor protein arrays. The protein assays showed that CSC and nicotine treated P. gingivalis cells had less pro-tein than the others. The total protein in the supernatant for the CSC treated bacteria was less compared to others. The protein data suggests that CSC and nicotine affect protein expression in and by the P. gingivalis cells. To-bacco-treated bacteria are hypothesized to increase the expression of pro-inflammatory cytokines/growth factors by the epithelial cells, thereby con-tributing to the inflammation seen in periodontal diseases. This research was funded by Indiana University-Purdue University Indianapolis, Multidisci-plinary Undergraduate Research Institute (MURI).