Browsing by Subject "Epithelial cells"

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Open Access
Cornea engineering on polyester carriers
(John Wiley & Sons, Inc., 2006) Zorlutuna, P.; Tezcaner, A.; Kiyat, I.; Aydınlı, Atilla; Hasirci, V.
In this study, biodegradable polyester based carriers were designed for tissue engineering of the epithelial and the stromal layers of the cornea, and the final construct was tested in vitro. In the construction of the epithelial layer, micropatterned films were prepared from blends of biodegradable and biocompatible polyesters of natural (PHBV) and synthetic (P(L/DL)LA) origin, and these films were seeded with D407 (retinal pigment epithelial) cells. To improve cell adhesion and growth, the films were coated with fibronectin. To serve as the stromal layer of the cornea, highly porous foams of P(L/DL)LA-PHBV blends were seeded with 3T3 fibroblasts. Cell numbers on the polyester carriers were significantly higher than those on the tissue culture polystyrene control. The cells and the carriers were characterized scanning electron micrographs showed that the foam was highly porous and the pores were interconnected. 3T3 Fibroblasts were distributed quite homogeneously at the seeding site, but probably because of the high thickness of the carrier (∼6 mm); they could not sufficiently populate the core (central parts of the foam) during the test duration. The D407 cells formed multilayers on the micropatterned polyester film. Immunohistochemical studies showed that the cells retained their phenotype during culturing; D407 cells formed tight junctions characteristic of epithelial cells, and 3T3 cells deposited collagen type I into the foams. On the basis of these results, we concluded that the micropatterned films and the foams made of P(L/DL)LA-PHBV blends have a serious potential as tissue engineering carriers for the reconstruction of the epithelial and stromal layers of the cornea.
Open Access
S-carboxymethylcysteine inhibits the attachment of Streptococcus pneumoniae to human pharyngeal epithelial cells
(Elsevier, 2003) Cakan, G.; Turkoz, M.; Turan, T.; Ahmed, K.; Nagatake, T.
Streptococcus pneumoniae causes respiratory and other invasive infections. Increased resistance of this bacterium to antibiotics necessitates new approaches to the treatment of infections. Attachment of bacteria to human pharyngeal epithelial cells is the initial step in the pathogenesis of infection and S-carboxymethylcysteine (S-CMC) can modulate the attachment of Moraxella catarrhalis and nontypable Haemophilus influenzae to epithelial cells. Unlike these two, S. pneumoniae is gram-positive and has a well-defined capsule. Here we examined the effects of S-CMC on the attachment and detachment of S. pneumoniae to human pharyngeal epithelial cells in vitro. Treatment of these cells with S-CMC significantly reduced the number of attached S. pneumoniae. S-CMC also resulted in a significant increase in the detachment of already attached S. pneumoniae to epithelial cells. In addition, treatment of S. pneumoniae with S-CMC significantly reduced their ability to attach to epithelial cells, but not the number of viable bacteria. Our study shows that S-CMC modulates the attachment of S. pneumoniae to human pharyngeal epithelial cells by acting both on cells and bacteria. © 2003 Elsevier Science Ltd. All rights reserved.
Open Access
Sulfatide mediates attachment of Pseudomonas aeruginosa to human pharyngeal epithelial cells
(Edizioni Medico Scientifiche, 2007) Yagci, A.; Yagci, T.; Sener, B.; Suziki, Y.; Ahmed, K.
Pseudomonas aeruginosa infections are particularly common in people with cystic fibrosis and despite regular treatment with antibiotics, lung damage due to chronic infection with P. aeruginosa remains the major cause of death in those patients. In order to initiate an infection, P. aeruginosa needs contact with the respiratory epithelial surface and by means of its adhesins i.e., fimbria, hemagglutinins,etc., it recognizes and adheres to the corresponding epithelial receptors. We treated P. aeruginosa strains isolated from sputum of cystic fibrosis patients with several glycolipids such as sulfatide, sulfated ganglioside mixture (GM1a, GD1b, GT1b), asialo-GM1 and galactocerebrosides to determine their effect on attachment with pharyngeal epithelial cells. Sulfated ganglioside mixture and sulfatide inhibited the attachment of P. aeruginosa significantly, whereas asialo-GM1, Gal-Cer and sodium sulfite had no effect on attachment inhibition. This finding suggests that sulfated glycoconjugates found in the extracellular matrix, in mucus and on the surface of epithelial cells of human trachea and lung mediates attachment of P. aeruginosa.
Open Access
Surface-modified bacterial nanofibrillar PHB scaffolds for bladder tissue repair
(Taylor and Francis Ltd., 2016) Karahaliloǧlu, Z.; Demirbilek, M.; Şam, M.; Saǧlam, N.; Mizrak, A. K.; Denkbaş, E. B.
The aim of the study is in vitro investigation of the feasibility of surface-modified bacterial nanofibrous poly [(R)-3-hydroxybutyrate] (PHB) graft for bladder reconstruction. In this study, the surface of electrospun bacterial PHB was modified with PEG- or EDA via radio frequency glow discharge method. After plasma modification, contact angle of EDA-modified PHB scaffolds decreased from 110 ï¿½ 1.50 to 23 ï¿½ 0.5 degree. Interestingly, less calcium oxalate stone deposition was observed on modified PHB scaffolds compared to that of non-modified group. Results of this study show that surface-modified scaffolds not only inhibited calcium oxalate growth but also enhanced the uroepithelial cell viability and proliferation.
Open Access
Variation in the attachment of Streptococcus pneumoniae to human pharyngeal epithelial cells after treatment with S-carboxymethylcysteine
(2008) Suer, E.; Sayrac, S.; Sarinay, E.; Ozturk H.E.; Turkoz, M.; Ichinose, A.; Nagatake, T.; Ahmed, K.
S-carboxymethylcysteine (S-CMC) is a mucolytic agent that can prevent respiratory infection by decreasing the attachment of respiratory pathogens to human pharyngeal epithelial cells (HPECs). Streptococcus pneumoniae is a major cause of respiratory infections. A previous study revealed that treatment of S. pneumoniae with S-CMC caused a decrease in the attachment of this bacterium to HPECs. In the present study we found that the effect of S-CMC varied according to hosts and strains. S-CMC treatment altered the surface structure of S. pneumoniae, resulting in a decrease of attachment, without affecting the virulence of the bacteria. © 2008 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases.