Pluripotent stem cells can differentiate into various lineages but undergo genetic and epigenetic changes during long-term cultivation and, therefore, require regular monitoring. The expression patterns of cancer-testis antigens (CTAs) MAGE-A2, -A3, -A4, -A6, -A8, -B2, and GAGE were examined in undifferentiated human embryonic stem (hES) cells, their differentiated derivatives, teratocarcinoma (hEC) cells, and cancer cell lines of neuroectodermal and mesodermal origin. Undifferentiated hES cells and embryoid body cells expressed MAGE-A3, -A6, -A4, -A8, and GAGEs while later differentiated derivatives expressed only MAGE-A8 or MAGE-A4. Likewise, mouse pluripotent stem cells also express CTAs of Magea but not Mageb family. Despite similarity of the hES and hEC cell expression patterns, MAGE-A2 and MAGE-B2 were detected only in hEC cells but not in hES cells. Moreover, our analysis has shown that CTAs are aberrantly expressed in cancer cell lines and display low tissue specificity. The identification of CTA expression patterns in pluripotent stem cells and their derivatives may be useful for isolation of abnormally CTA-expressing cells to improve the safety of stem-cell based therapy.

New human nonimmortalized fibroblast like cell lines were derived from various sources: from embryonic stem cells (ESCs) (the SC5 MSC and SC3a MSC lines), from bone marrow of a 5 to 6 week old fetus (the FetMSC line), and from foreskin of a 3 year old child (the FRSN line). All the lines are suc cessfully used as feeders during cultivation of human ESCs. The mean doubling time of the cell populations fluctuates depending on the line from 25.5 h in the SC5 MSC line to 38.8 h in the SC3a MSC line. The growth curves indicate active cell proliferation of all lines. Numerical and structural karyotypical analysis has shown these lines to have a normal karyotype: 46, XX (SC5 MSC and SC3a MSC) and 46, XY (FetMSC and FRSN). To determine the status of these lines, comparative analysis of surface markers was performed with the aid of flow cytofluorimetry, and expression of the c antigens characteristic of human mesenchymal stem cells (MSCs) was revealed: CD44, CD73, CD90, CD105, and HLA ABC and the absence of expression of CD34 and HLA DR. Interlinear differences in the expression level of the marker CD117 (c kit) were revealed. Immunofluorescent and cytofluorimetric analysis of expression of surface markers and transcrip tion factor Oct 4 that are characteristic of human ESCs has shown that, in all four lines, expression of TRA 1 60 and Oct 4 is absent, whereas in expression of SSEA 4 there are observed the interlinear differ ences not depending on the origin of cells. At present it is not yet clear whether the revealed interlinear dif ferences affect essentially the functional status of mesenchymal stem cells. Immunofluorescent analysis in cells of all lines showed expression of markers of early differentiation into derivatives of three germ layers characterizing ESCs, which might possibly provide wide MSC possibilities during reparation of different tis sue damages, depending on the corresponding microenvironment. The capability of cells of all lines for directed differentiation into the adipogenic and osteogenic directions was revealed.

Purpose: Raman scattering spectra can be thought of as the "fingerprints" of the investigated material. The purpose of this work was to link the absorbed doses of irradiated radiochromic film at the micrometer level with changes in their Raman spectra. Methods: Raman spectra of irradiated GAFCHROMIC EBT3 film with doses ranging from 0 to 40 Gy were acquired. The excitation wavelengths used in the experiments (457.9 and 647.1 nm) coincided with electronic transitions of the active layer of the film. The effect of resonance Raman scattering enhanced Raman peaks in the resonance region. Spectra were taken in the range of room temperature to around the temperature of liquid nitrogen (À190°C). Results: The Raman peak intensity redistribution is shown for films with different absorbed doses. The ratio of intensities of the 1445 cm À1 band with respect to the 1330 cm À1 band increases with the increase in absorbed dose. This allows building a dose calibration curve for the film. Conclusion: The dose distribution of the irradiated film can be identified based on the intensity ratio of the 1445 and 1330 cm À1 bands by means of Raman mapping. This is a noninvasive and computerized readout method which provides micrometer resolution results for the film surface. This is beneficial in the use of radiochromic films as dosimeters for high-precision radiotherapies.

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