hTERT-Driven Immortalization of RDEB Fibroblast and Keratinocyte Cell Lines Followed by Cre-Mediated Transgene Elimination

The recessive form of dystrophic epidermolysis bullosa (RDEB) is a crippling disease caused by impairments in the junctions of the dermis and the basement membrane of the epidermis. Using ectopic expression of hTERT/hTERT + BMI-1 in primary cells, we developed expansible cultures of RDEB fibroblasts and keratinocytes. We showed that they display the properties of their founders, including morphology, contraction ability and expression of the respective specific markers including reduced secretion of type VII collagen (C7). The immortalized keratinocytes retained normal stratification in 3D skin equivalents. The comparison of secreted protein patterns from immortalized RDEB and healthy keratinocytes revealed the differences in the contents of the extracellular matrix that were earlier observed specifically for RDEB. We demonstrated the possibility to reverse the genotype of immortalized cells to the state closer to the progenitors by the Cre-dependent hTERT switch off. Increased β-galactosidase activity and reduced proliferation of fibroblasts were shown after splitting out of transgenes. We anticipate our cell lines to be tractable models for studying RDEB from the level of single-cell changes to the evaluation of 3D skin equivalents. Our approach permits the creation of standardized and expandable models of RDEB that can be compared with the models based on primary cell cultures.     

The chemico-pharmacological patterns in the action of plants from the family of Pyrolaceae

The effect of leaf decoctions of three plants of the Pyrolaceae family, namely, umbrella wintergreen, one-side ortilia, and round-leaf Pyrola was studied in rat experiments. All plants under study were found to contain approximately equal amounts of tannins and arbutin glycoside. Their concentration was comparable though rather lower than in common bearberry, a well-known plant with diuretic and antiseptic activity. When given for a long time, all Pyrolaceae increased urination and sodium excretion. Besides, their decoctions caused an antimicrobial effect. Only round-leaf Pyrola weakened the development of experimental inflammation. Its anti-inflammatory effect was probably due the presence of flavonoids the content of which in Pyrola was maximum.     

Effect of supramolecular structure on polymer nanofibre elasticity

Polymer materials of reduced size and dimensionality, such as thin films, polymer nanofibres and nanotubes, exhibit exceptional mechanical properties compared with those of their macroscopic counterparts. We discuss here the abrupt increase in Young's modulus in polymer nanofibres. Using scaling estimation we show that this effect occurs when, in the amorphous (non-crystalline) part of the nanofibres, the transversal size of regions consisting of orientation-correlated macromolecules is comparable to the nanofibre diameter, thereby resulting in confinement of the supramolecular structure. We suggest that in polymer nanofibres the resulting supramolecular microstructure plays a more dominant role in the deformation process than previously thought, challenging the commonly held view that surface effects are most significant. The concept we develop also provides a way to interpret the observed--but not yet understood--temperature dependence of Young's modulus in nanofibres of different diameters.     

The features of ribbon-like polymers in thin films

The features of ribbon-like polymers in thin film, which are anisotro-pic in cross section, are considered using a lattice model of oriented self-correlated walks (OSCW). The local properties of the ribbon-like chain are assumed to be strongly anisotropic: bending is possible only in the plane of the ribbon (the orientation of this plane can change due to molecule twist). On the basis of this model, the phase transition of the ribbon-like polymers possessing certain bending and twist rigidity into the rotator phase is described in the mean-field approximation. The dimension reducing of the polymer system results in an increase of phase transition temperature. Moreover, spontaneous polarization arises in a non-orientated system and that is the most interesting phenomenon caused by confinement of polymer macromolecules.