Iron is a microelement with the most completely studied biological functions. Its wide dissemination in nature and involvement in key metabolic pathways determine the great importance of this metal for uni- and multicellular organisms. The biological role of iron is characterized by its indispensability in cell respiration and various biochemical processes providing normal functioning of cells and organs of the human body. Iron also plays an important role in the generation of free radicals, which under different conditions can be useful or damaging to biomolecules and cells. In the literature, there are many reviews devoted to iron metabolism and its regulation in pro- and eukaryotes. Significant progress has been achieved recently in understanding molecular bases of iron metabolism. The purpose of this review is to systematize available data on mechanisms of iron assimilation, distribution, and elimination from the human body, as well as on its biological importance and on the major iron-containing proteins. The review summarizes recent ideas about iron metabolism. Special attention is paid to mechanisms of iron absorption in the small intestine and to interrelationships of cellular and extracellular pools of this metal in the human body.

The influence of modified nanosized magnetite (NSM) particles (magnetic microspheres coated with chitosan and magnetoliposomes) after a single intravenous infusion of their suspensions on iron metabolism in rats has been studied. Modern physical and chemical methods (X-ray fluorescence, dynamic light scattering, transmission electron microscopy) were used for standardization of the modified NSM particles (their size, structure, ζ-potential, and concentration were determined). Atomic emission spectroscopy was used to reveal the dynamics of iron content in rat liver, spleen, lungs, and kidneys during 120 days. Colorimetric and immunoturbidimetric methods were used to determine the concentrations of plasma iron and the proteins involved in its metabolism - ceruloplasmin, transferrin, and ferritin. Their dynamics throughout the experiments were studied.

Цель. Провести морфофункциональную характеристику эпителиоцитов ацинусов и протоков поднижнечелюстных слюнных желез (ПСЖ) половозрелых крыс на фоне многократной ампутации резцов. Материалы и методы. Эксперимент проведен на половозрелых (возраст 2 мес) белых беспородных самцах крыс, разделенных на группы: интактная, контрольная и группа крыс, подвергшихся многократной ампутации резцов. При помощи гистологических, гистохимических и морфометрических методов оценено морфофункциональное состояние эпителиоцитов протоков и ацинусов ПСЖ половозрелых крыс на 2-, 3-, 4-, 6-, 8-, 10-и 12-й нед после первой ампутации резцов. Результаты. После многократной ампутации резцов наблюдается увеличение площади ацинусов ПСЖ на 3-10-й нед эксперимента. Функциональная активность клеток протоков и ацинусов поднижнечелюстных желез снижается на 2-4-й нед эксперимента. * отличие от аналогичного показателя животных интактной группы; # отличие от показателя предыдущей недели ýтой же группы, достигнутый уровень значимости р < 0,05.

The ultrastructure of nephrocytes of the proximal and distal convoluted tubules, podocytes, mesangial cells, and macrophages of the interstitial connective tissue was studied after single intravenous administration of magnetite nanoparticles modified with chitosan (magnetic nanospheres) or lipids (magnetic liposomes). Transmission electron microscopy showed ultrastructural features of absorption of magnetite nanoparticles. The shape, size, and number of vesicles containing nanoparticles in nephrocytes of convoluted tubules and macrophages after administration of the suspensions of magnetic nanospheres and magnetic liposomes were described.

The paper shows that it is expedient to modify the surface of the heart valve leaflets in order to create favorable conditions for the attachment and function of endothelial progenitor cells.

Aim of the study. We attempted to obtain the Mn-HMPAO complex (Mangoxim) and to evaluate the possibility to apply as a paramagnetic contrast agent for enhancement of tumors at MRI. Materials and methods. The synthesis of HMPAO was carried out by using R. D. Neirinckx — J. Pijarowska-Kruszyna technique (2017), without separation of enantiomers. The Mn-HMPAO was obtained by mixing Manganese(II) carbonate with HMPAO, pH 6,2–6,5, 0,5 M. Also the quantum chemistry calculations were carried out on the structure of Mn-HMPAO using method of functional of density DFT rb3lyp/6–31+g(d,p) for isolated molecules and for water solutions (CPCM). MRI study of Mn-HMPAO uptake carried out in twelve laboratory mouses with transplanted Lewis sarcoma, in T1-w. SE mode, TR=500 ms, TE=15 ms, 256×256 matrix, FOV 15×15 cm, 3 mm thin slice. MRI acquired in 15–17 min and 60–90 min after intravenous injection of the Mn-HMPAO. The uptake was quantified as index of enhancement: IE=(Int. T1-w.MRI)Mn-HMPAO/(Int. T1- w.MRI)pre-contrast. Results. The N,N-Mn-dioxim is more stable than O,O-Mn-dioxim for 50,5 KCal/mol, so in the nature only N,N-Mn-dioxim exists. R1 of Mn-HMPAO was 3,35 1/(mM•s), below R1 of gadopentetate=3,96 1/(mM•s). The highest value of early IE was over the tumor (3,36±0,31) and over lungs (3,07±0,43). At 60 min the IE over tumor decreased to 1,58±0,14, remaining far over IE values over any other location. Conclusion. The Mn-HMPAO complex demonstrates paramagnetic properties for the application as the contrast MRI agent and probably will improve the selective enhancement of tumors.

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The use of nanomaterials offers many advantages due to their unique properties. They can be used as building blocks for the fabrication of various functional diagnostic systems and agents of therapy. This article focuses on the application of magnetic nanoparticles in biomedicine such as magnetic separation, biosensor, contrast agents for MRI (magnetic resonance imaging), local operated hyperthermic treatment of tumors, drug delivery, gene therapy, tissue engineering.