BIOLOGICAL PECULIARITIES OF ADIPOSE TISSUE-DERIVED MESENCHYMAL STEM CELLS AT DIFFERENT PASSAGES OF CULTIVATION

The studies were conducted on 2–3-months-old males of C57BL/6 mice weighing 20–24 g. Obtaining and operating with adipose tissue-derived mesenchymal stem cell (MSC) culture was performed in a sterile laminar box under conditions of asepsis and antiseptics. The adipose tissue-derived MSC of the 2, 4, 7 and 12 passages were analyzed. Morphometric analysis was performed using a light microscopy. Morphometric parameters such as cell and nucleus area or nuclear-cytoplasmic ratio were calculated using the Axiovision light microscope (Carl Zeiss, Germany) and Image J 1.45 software. Trypan blue dye used for investigation of the viability of MSC. The morphological characteristics of adipose tissue-derived MSC during the process of cultivation changes: at the first passages of cultivation, the cells are spindle-shaped with two, at least three, long cytoplasmic processes, which are located bipolar. Near the nucleus, the Golgi complex is clearly visible – a sign of active cells. At later passages, cells have a small cytoplasmic processes and the bipolar arrangement of processes changes by stellar arrangement. Golgi complex is also clearly visualized. The indicator of the nuclear-cytoplasmic ratio in MSC from adipose tissue is significantly reduced at the 7th passage to 0.2189 ± 0.0122 (P < 0.01), and at the 12th passage to 0.1111 ± 0.0086 (P < 0.001) compared to the 2nd passage. The coefficient of proliferation of adipose tissue-derived MSC is significantly reduced at 12th passage. The viability of MSC from adipose tissue with an increasing of a number of passages significantly reduces and at the 12th passage of cultivation reaches 84.67 ± 1.36 (P < 0.05). The content of apoptotic cells that exhibited sensitivity to serum-free cultivation significantly increased at the 7th and 12th passages and was 21.33 ± 1.36 (P < 0.05) and 23.67 ± 0.97% (P < 0.05), respectively.

Effect of Pavement Thickness and Width on Liquefaction-Induced Settlements and the Contribution of Sand Ejecta in Total Settlement

This paper investigates the settlement in a pavement due to soil liquefaction. Four 1-g shaking table tests were performed on saturated sand bed-pavement model to understand the factors affecting the liquefaction-induced settlements and their relation to the pavement thickness and width. All the tests were performed with a base acceleration of 320 gal in a laminar box. The shaking table tests revealed that the total settlement reduced with the increase in the pavement thickness. The pavement with the same thickness but different width showed that the total settlement reduced with the increase in the pavement width. The co-seismic settlement and post-seismic settlement depend upon the thickness and width of the pavement, and the maximum contribution of the sand ejecta is around 7.7% in the total settlement.

ENSURING BIOLOGICAL SAFETY DURING LYOPHILIZATION FOR MICROORGANISMS OF I–II PATHOGENICITY GROUPS

The article shows the presence of pathogen single cells of a dried sample in swabs taken from the camera surfaces of sublimation machines after lyophilization is completed, which may entail the possibility of release in the form of aerosol of viable cells of lyophilized microorganisms and lead to the creation of dangerous to personnel emergency situation. We proposed the use of additional isolation equipment - laminar box equipped with H14 class HEPA filters, the purpose of which is to protect the operator and the environment when working with pathogenic biological agents. The swabs taken from the internal surfaces of the laminar box and lyophilic machines at the end of the process gave negative results, which minimized the aerosol formation risk in room of the bacteriological box. We selected personal protective equipment, disinfectants for processing equipment and the final product, developed an algorithm for personnel actions, which made it possible to significantly increase the level of protection against pathogens of laboratory staff and the environment.