In vivo study of porous NiTi cryotweezers for bone tissue cryotherapy.

This study examined the effects of liquid nitrogen vapor on osteogenesis in the rabbit femur. Cryotweezers made of porous nickel titanium alloy (nitinol or NiTi) obtained by self-propagating high temperature synthesis were used in this experiment. The porous structure of the cryotweezers allows them to hold up to 10 g of liquid nitrogen after being immersed for 2 min, which completely evaporates after 160 s. To study the effects of liquid nitrogen evaporation on osteogenesis, a rabbit femur was perforated. The formed holes were subjected to cryotherapy with varying exposure times. It was found that a 3 s exposure time stimulates osteogenesis, which was manifested in a greater number of osteoblasts in the regenerate compared to the control sample without liquid nitrogen. It was observed that increasing the exposure to 6, 9 or 12 s had a destructive effect, to varying degrees. The most severe damage was exerted by a 12 s exposure, which resulted in the formation of osteonecrosis areas. In the samples exposed to 6 and 9 s of cryotherapy, destruction of the cytoplasm of osteocytes and osteoclasts was observed.

Immunomodulatory Activity of Polysaccharides Isolated from Saussurea salicifolia L. and Saussurea frolovii Ledeb.

The genus Saussurea has been used in the preparation of therapies for a number of medical problems, yet not much is known about the therapeutic high-molecular-weight compounds present in extracts from these plants. Since polysaccharides are important in immune modulation, we investigated the chemical composition and immunomodulatory activity of Saussurea salicifolia L. and Saussurea frolovii Ledeb polysaccharides. Water-soluble polysaccharides from the aerial parts of these plants were extracted using water at pHs of 2 and 6 and subsequently precipitated in ethanol to obtain fractions SSP2 and SSP6 from S. salicifolia and fractions SSF2 and SSF6 from S. frolovii. The molecular weights of fractions SSP2, SSP6, SFP2, and SFP6 were estimated to be 143.7, 113.2, 75.3, and 64.3 kDa, respectively. The polysaccharides from S. frolovii contained xylose (67.1-71.7%) and glucose (28.3-32.9%), whereas the polysaccharides from S. frolovii contained xylose (63.1-76.7%), glucose (11.8-19.2%), galactose (4.7-8.3%), and rhamnose (6.8-9.4%). Fractions SSP2, SSP6, and SFP2 stimulated nitric oxide (NO) production by murine macrophages, and NO production induced by SSP2, SSP6, and SFP2 was not inhibited by polymyxin B treatment of the fractions, whereaspolymyxin B treatment diminished the effects of SFP6, suggesting that SFP6 could contain lipopolysaccharide (LPS). The LPS-free fractions SSP2, SSP6, and SFP2 had potent immunomodulatory activity, induced NO production, and activated transcription factors NF-κB/AP-1 in human monocytic THP-1 cells and cytokine production by human MonoMac-6 monocytic cells, including interleukin (IL)-1α, IL-1ß, IL-6, granulocyte macrophage colony-stimulating factor (GM-CSF), interferon-γ, monocyte chemotactic protein 1 (MCP-1), and tumor necrosis factor (TNF). These data suggest that at least part of the beneficial therapeutic effects reported for water extracts of the Saussurea species are due to the modulation of leukocyte functions by polysaccharides.

Quantitative Structure-Activity Relationship, Ontology-Based Model of the Antioxidant and Cell Protective Activity of Peat Humic Acids.

Peat humic acids are well known for their wide range of biological effects which can be attributed to the complex chemical structure of naturally occurring humic substances. One of the promising tools is an ontology-based quantitative analysis of the relationship between physical and chemical parameters describing a chemical structure of peat humic acids and their biological activity. This article demonstrates the feasibility of such an approach to estimate the antioxidant and cell protective properties of the peat humic acids. The structural parameters of the peat humic acids were studied by electronic, fluorescence, infrared, 13C-NMR spectroscopy, titrimetric analysis, elemental C,H,N, and O- analysis, and gel chromatography. Antioxidant and antiradical activities were assessed by physicochemical methods of analysis: electronic paramagnetic resonance, cathodic voltammetry, ABTS•+ scavenging, assay of DPPH radical-scavenging activity, assay of superoxide radical-scavenging activity, iron chelating activity, and scavenging of hydroxyl radicals. Cytoprotective activity was evaluated by the neutral red-based cytotoxicity test in 3T3-L1 cell culture in a wide range of concentrations. Assessment of intracellular ROS production was carried out using a 2,7-dichlorodihydrofluoresceindiacetate (DCFDA) fluorescent probe. Intracellular ROS production was induced using two common prooxidants (tert-butyl hydroperoxide, Fe2+ ions). We suggested an ontology-based model for the antioxidant and cytoprotective activity of humic acids based on experimental data and numerical models. This model establishes the way to further research on the biological effects of humic acids and provides a useful tool for numerical simulation of these effects. Remarkable antioxidant and cell protective activity of humic acids makes them a promising natural source of new pharmaceutical substances that feature a wide range of biological effects.

In Vitro Biodegradation of a-C:H:SiOx Films on Ti-6Al-4V Alloy.

This paper focuses mainly on the in vitro study of a five-week biodegradation of a-C:H:SiOx films of different thickness, obtained by plasma-assisted chemical vapor deposition onto Ti-6Al-4V alloy substrate using its pulsed bipolar biasing. In vitro immersion of a-C:H:SiOx films in a solution of 0.9% NaCl was used. It is shown how the a-C:H:SiOx film thickness (0.5-3 µm) affects the surface morphology, adhesive strength, and Na+ and Cl- precipitation on the film surface from the NaCl solution. With increasing film thickness, the roughness indices are reducing a little. The adhesive strength of the a-C:H:SiOx films to metal substrate corresponds to quality HF1 (0.5 µm in thickness) and HF2-HF3 (1.5-3 µm in thickness) of the Rockwell hardness test (VDI 3198) that defines strong interfacial adhesion and is usually applied in practice. The morphometric analysis of the film surface shows that on a-C:H:SiOx-coated Ti-6Al-4V alloy surface, the area occupied by the grains of sodium chloride is lower than on the uncoated surface. The reduction in the ion precipitation from 0.9% NaCl onto the film surface depended on the elemental composition of the surface layer conditioned by the thickness growth of the a-C:H:SiOx film. Based on the results of energy dispersive X-ray spectroscopy, the multiple regression equations are suggested to explain the effect of the elemental composition of the a-C:H:SiOx film on the decreased Na+ and Cl- precipitation. As a result, the a-C:H:SiOx films successfully combine good adhesion strength and rare ion precipitation and thus are rather promising for medical applications on cardiovascular stents and/or friction parts of heart pumps.

Constituent composition of the essential oils from some species of the genus Saussurea DC.

The genus Saussurea DC is well known for its rich chemical composition and wide range of biological activities. Although content and biological effects of major chemical components are thoroughly studied, the composition and concentrations of minor constituents, such as essential oils, still remains unclear. In total, 62 different chemical compounds have been identified in the essential oils from S. controversa, S. latifolia, S. parviflora and S. salicifolia using a gas chromatography-mass spectrometry method. The essential oils include 1-5% of linalool, 2-7% of eudesmol and oxygen-containing sesquiterpenoids: 7-25% of caryophyllene oxide, 4-5% of spathulenol, 4-6% of humulene-6.7-oxide. The presence of sesquiterpenoids can be considered as a chemotaxonomic feature of the studied species of Saussurea DC. The essential oils can be candidates for new anti-inflammatory, analgesic and anti-tumor drugs due to relatively high concentration of caryophyllene oxide.