Kathrin Duske

Influence of phytoestrogens on the proliferation and expression of adhesion receptors in human mammary epithelial cells in vitro.

Tumor metastasis is associated with integrin-mediated adhesion and hyaluronan receptor expression. Accumulating evidence suggests that phytoestrogens, which are naturally occurring, plant-derived phytochemicals, could inhibit tumorigenesis during the development of breast cancer. Less is known, however, about the regulation of adhesion receptors by phytoestrogens and, particularly, their potency to influence proliferation of primary human breast cells in comparison with the steroid hormone 17&bgr;-estradiol. Throughout the proliferation experiments, we used primary human mammary epithelial cells from normal tissue that was derived from plastic surgery. For receptor expression (&bgr;1, &agr;2, &agr;3, CD44), we used the cell line MCF-7. Both investigations were carried out by flow cytometry. The phenotype of primary human mammary epithelial cells was microscopically characterized by analyzing the distribution of ZO-1, cytokeratin and the estrogen receptors &agr; and &bgr;. The integrins and the hyaluronan receptor were significantly up-regulated with 17&bgr;-estradiol in human MCF-7 cells. In contrast, genistein and daidzein did not affect the expression at a concentration of 100 μmol/l. In all proliferation experiments with a significant stimulation of the primary human mammary epithelial cell growth due to 17&bgr;-estradiol, in general, genistein and daidzein did not influence S-phase and G2/M-phase cells. Additionally, the stimulative effect of 17&bgr;-estradiol could be inhibited. As the phytoestrogens do not up-regulate adhesion receptors in human breast cells and, regarding proliferation, are able to abolish the stimulatory effect of 17&bgr;-estradiol, we suggest that phytoestrogens could have beneficial effects for the prevention or inhibition of carcinogenesis in hormone-dependent malignancies.

Comparison of Nonthermal Plasma Processes on the Surface Properties of Polystyrene and Their Impact on Cell Growth

The initial adhesion and spreading of cells are crucial factors for the successful performance of a synthetic biomaterial used for cell culture disposables or human medical devices (e.g., implants). Surface properties which allow the control of the attachment of cells are decisive for the acceptance of the provided material. Hence, different surface preparation techniques are used to equip surfaces with functional groups to improve initial surface interactions. In this paper, polystyrene (PS) surfaces were modified by using different nonthermal plasma processes. In particular, low-pressure plasma and atmospheric-pressure plasma were applied to modify surfaces or to deposit thin films on surfaces. Furthermore, the behaviors of human osteoblastic cells with respect to cell viability and cell growth on differently plasma treated PS surfaces are investigated. A comparison is made between plasma-grafted PS and commercially available PS-such as tissue-culture PS and Primaria. The cell studies were accompanied by surface analysis comprising atomic force microscopy, determination of surface energies, and X-ray photoelectron spectroscopy measurements. This work demonstrates that the functionalization of PS substrates by applying low-pressure and atmospheric-pressure plasma processes are equally effective in the improvement of cell attachment and proliferation. Furthermore, it is shown that the enhanced metabolic activity and spreading behavior of osteoblastic cells correlate well with an increase in surface wettability and the introduction of polar oxygen- and/or nitrogen-containing functional groups after plasma treatment.

Plasmaanwendungen in der Zahn-, Mund- und Kieferheilkunde

Plasma kann zum Abtrag von dentalen Plaquebiofilmen und der Desinfektion von Oberflachen bei physiologischen Temperaturen genutzt werden. Zudem kann uber die reaktiven Prozesse an der Implantatoberflache die Oberflachenenergie zugunsten einer gesteigerten Hydrophilie verandert werden. Dieser Prozess unterstutzt die Adhasion von Bindegewebs- und Knochenzellen am Implantat und damit auch moglicherweise auch die Wundheilungsprozesse. Die beschriebenen Effekte zum Abtrag organischen Materials und zur Desinfektion konnen zur hauslichen Aufbereitung dentaler Prothesen genutzt werden, um das Risiko einer prothesenassoziierten Stomatitis zu verringern. Plasma besitzt auch eine gute Spaltgangigkeit und kann damit auch an schwer erreichbaren Stellen seine antimikrobielle Wirkung entfalten. Diese Eigenschaft eroffnet fur kaltes Plasma eine weitere Therapieanwendung im Bereich der Wurzelkanalbehandlung.