Transplantation of human bone marrow mesenchymal stem cells is considered as a promising therapeutic approach to the therapy of many diseases. However, the problem of possible alterations of the ...properties of mesenchymal stem cells during their expansion in in vitro cultures before transplantation is not solved. In our study, one of two hundred examined cultures of mesenchymal stem cell cultures derived from donors without bone marrow pathologies and developed under standard culturing conditions demonstrated spontaneous disturbances in morphology, proliferation, and karyotype at early passages. The cells of this abnormal culture retained immunophenotype characteristic of normal mesenchymal stem cells, but some of them (15-25%) had numerous numerical and structural chromosome aberrations.
Since modern synchrotrons with highly intense X-ray beams are in use to investigate organic materials, the stability of soft matter materials during beam exposure is a crucial issue. Grazing ...incidence X-ray diffraction and specular X-ray reflectivity measurements were performed on thin films of organic semiconducting materials, like poly(3-hexylthiophene) (P3HT), sexithiophene and pentacene. These films were irradiated with an average flux density between 1015 and 1016photons/(smm2) and evidenced a different stability in synchrotron X-ray radiation. The semi-crystalline P3HT showed a clear intensity decrease of the 100 Bragg peak and 020 Bragg peak compared to the rather stable diffraction features of the molecular crystals sexithiophene and pentacene. The difference in synchrotron X-ray radiation stability is explained by the interaction of the X-ray beam with the individual chemical components in the molecules as well as by the different crystallinities of the materials. Furthermore, the semi-crystalline P3HT film exhibited an increase of film thickness after irradiation and the surface roughness slightly decreased. To summarize, this study shows a strong influence of synchrotron X-ray radiation to specific organic thin films like e.g. P3HT, while others like pentacene and sexithiophene are observed as quite stable.
The main stream of biology today is the analysis of the molecular mechanisms of major biological phenomena through studies of the genes governing these processes and their protein products. An ...example is the problem of tumor metastasis which is extremely important both theoretically and practically. Here we describe the data obtained on the detection, cloning, structure and transcription control of the mts1 gene, that encodes metastasin 1, a protein which seems to play an important role in the control of metastasis in mouse tumors. In particular, the experiments on tumor cell transfection with constructions containing either a sense or antisense mts1 sequence under a strong promoter/enhancer element show the direct dependence of the metastatic phenotype on the expression of the mts1 gene at least in some systems. Gene mts1 encodes a protein belonging to the family of Ca(2+)-binding proteins and may be involved in the control of cell motility in different types of cells, such as macrophages and T-lymphocytes. The relationship between mts1 and other genes up- and down-regulated in metastatic cells is discussed.
We studied the effect of various methods of transplantation of mesenchymal stem cells on neuronal survival in rat brain 1 and 6 weeks after severe traumatic brain injury. It was found that ...intracerebral and systemic transplantation of mesenchymal stem cells improves neuronal survival in the piriform cortex of the contralateral hemisphere without affecting neuronal survival in the marginal zone of the traumatic cavity and amygdaloid nuclei. Intracerebral transplantation of mesenchymal stem cells increases the content of the astroglial component of the scar in the borderline zone of the traumatic cavity.
A theory of thermal diffuse scattering (TDS) in a crystal disturbed by high frequency ultrasonic vibrations is considered. In this case additional X-ray reflexes (satellites) are formed which can be ...used for obtaining information about vibrational excitations in a crystal. By varying the incident angle one can excite all the satellites one after another and detect the variation in the TDS yield. The possibilities of the experimental observation of these phenomena will also be discussed.
Influence of a high-molecular compound capable of augmenting viscosity, namely: polyethylene oxide Polyox WSR-301, on hemodynamic parameters in rat mesenteric microvessels was investigated. A ...substantial decrease in the arteriolar hemodynamic resistance caused by the polymer was revealed. Special research has shown that this reaction is not connected with a vasodilatation and, therefore, is caused by a reduction in the "apparent" viscosity of the blood, i.e., it is a consequence of changed properties of the blood flow.
