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Background: Several studies reported on periprosthetic infection after primary THA in HIV-positive patients, but very few showed the results of its revision. Objective: The aim was to compare primary and secondary clinical outcomes after revision arthroplasty for hip joint infection in matched groups of HIV-infected and HIV-negative patients. Methods: Using the hospital database, thirteen HIV-positive patients (13 infected hips) and thirteen HIV-negative patients of the matched control group (13 infected hips) were identified and their records were studied retrospectively. They underwent revision surgery aimed at infection arrest and total hip replacement due to infection developed after primary THA or infected spacers. Harris Hip Score, reinfection rate, limb shortening, and definite outcomes were evaluated with Wilcoxon, Mann-Whitney, and Chi-squared tests. Results and Discussion: Spacers with antibiotics were implanted in patients of both groups at the first step of revision, except for one HIV-infected patient who had resection arthroplasty. The mean follow-up was 29.4 ± 2.7 and 33. ± 2.9 months for the HIV-group and control group, respectively. Three patients of the HIV-group completed two-stage revision arthroplasty versus ten patients from the control group. Re-infection rate was higher in the HIV-group. At final follow-ups, the mean HHS was significantly different (53 ± 3.2 points in the HIV-group versus 79.14 ± 3.1 points in the control group) along with limb length discrepancy (3.71 ± 0.43 versus 1.4 ± 0.32). Conclusion: Both primary and secondary clinical outcomes of revision arthroplasty for hip joint infection in HIV-positive patients were significantly worse than in the matched group of HIVnegative patients. Revisions in HIV-positive group resulted in a higher reinfection rate, a small number of definite two-stage revisions, and lower functional scores.

A high risk of complications in burn injuries is associated with the development of systemic inflammatory response syndrome. Thermal injury (burn) causes the release of cytokines and prostaglandia, resulting in increased interaction between leukocytes, platelets and endothelial cells. Activation of leukocytes leads to an increase in the formation of reactive oxygen species (ROS) and nitrogen, which is normally compensated by the activation of protective antioxidant enzymes. An imbalance between the activity of the radical-producing and antioxidant systems leads to an excess of free radicals and the development of oxidative stress. Oxidative stress limits the repair of damaged tissue and also leads to localized chronic inflammation. Thus, the removal of inflammation and a decrease in the ROS level, which exceeds the physiological level in the burn zone, seems to be expedient for accelerating the healing process of burn injuries of the skin. In this study, we used a polysaccharide hydrogel modified with cerium dioxide (CeO2) nanoparticles, which have unique anti-inflammatory and antioxidant properties, as an effective agent for the treatment of thermal burns. It has been shown that modification of the hydrogel with CeO2 nanoparticles provides accelerated healing of a model burn wound in rats. Already on the 5th day after the treatment of damage to the skin with the modified hydrogel, a decrease in the area of ​​the burn wound that is different from the control is observed. The use of a hydrogel accelerates the healing process of a burn wound on the 25th day by 25.42% (p 2 nanoparticles can be considered as an effective wound healing agent in the treatment of thermal burns and skin lesions of various etiologies.

Gd-based complexes are widely used as magnetic resonance imaging (MRI) contrast agents. The safety of previously approved contrast agents is questionable and is being re-assessed. The main causes of concern are possible gadolinium deposition in the brain and the development of systemic nephrogenic fibrosis after repeated use of MRI contrasts. Thus, there is an urgent need to develop a new generation of MRI contrasts that are safe and that have high selectivity in tissue accumulation with improved local contrast. Here, we report on a new type of theranostic MRI contrast, namely dextran stabilised, gadolinium doped cerium dioxide nanoparticles. These ultra-small (4–6 nm) Ce0.9Gd0.1O1.95 nanoparticles have been shown to possess excellent colloidal stability and high r1-relaxivity (3.6 mM−1 s−1). They are effectively internalised by human normal and cancer cells and demonstrate dose-dependent selective cytotoxicity to cancer cells.

Ionising radiation causes the death of the most actively dividing cells, thus leading to depletion of the stem cell pool. Planarians are invertebrate flatworms that are unique in that their stem cells, called neoblasts, constantly replace old, damaged, or dying cells. Amenability to efficient RNAi treatments, the rapid development of clear phenotypes, and sensitivity to ionising radiation, combined with new genomic technologies, make planarians an outstanding tool for the discovery of potential radioprotective agents. In this work, using the well-known antioxidant N-acetylcysteine, planarians are, for the first time, shown to be an excellent model system for the fast and effective screening of novel radioprotective and radio-sensitising substances. In addition, a panel of measurable parameters that can be used for the study of radioprotective effects on this model is suggested.

Novel radioprotectors are strongly demanded due to their numerous applications in radiobiology and biomedicine, e.g., for facilitating the remedy after cancer radiotherapy. Currently, cerium-containing nanomaterials are regarded as promising inorganic radioprotectors due to their unrivaled antioxidant activity based on their ability to mimic the action of natural redox enzymes like catalase and superoxide dismutase and to neutralize reactive oxygen species (ROS), which are by far the main damaging factors of ionizing radiation. The freshwater planarian flatworms are considered a promising system for testing new radioprotectors, due to the high regenerative potential of these species and an excessive amount of proliferating stem cells (neoblasts) in their bodies. Using planarian Schmidtea mediterranea, we tested CeO2 nanoparticles, well known for their antioxidant activity, along with much less studied CeF3 nanoparticles, for their radioprotective potential. In addition, both CeO2 and CeF3 nanoparticles improve planarian head blastema regeneration after ionizing irradiation by enhancing blastema growth, increasing the number of mitoses and neoblasts’ survival, and modulating the expression of genes responsible for the proliferation and differentiation of neoblasts. The CeO2 nanoparticles’ action stems directly from their redox activity as ROS scavengers, while the CeF3 nanoparticles’ action is mediated by overexpression of “wound-induced genes” and neoblast- and stem cell-regulating genes.

This paper examines the effect of electromagnetic waves, with maxima in the green or red regions of the spectrum, on the morphofunctional state of multipotent mesenchymal stromal cells. The illumination regimes used in our experiments did not lead to any substantial heating of the samples; the physical parameters of the lighting were carefully monitored. When the samples were illuminated with a green light, no significant photostimulatory effect was observed. Red light, on the other hand, had an evident photostimulatory effect. It is shown that photostimulation with a red light decreases the enzymatic activities of mitochondrial dehydrogenases and enhances the viability of cells, their proliferative activity, and their ability to form bone tissue. It is also established that red light stimulates cell proliferation, while not activating the genes that increase the risk of the subsequent malignant transformation of cells or their death. This paper discusses the possible role of hydrogen peroxide in the processes examined.

—Morphogenetic effects of two exogenous sex steroid hormones, testosterone and estradiol, during planarian regeneration have been studied. Anterior regenerants, which retained the head ganglion after cutting, exhibited the highest sensitivity to the introduced hormones. The influence of the studied steroids on the growth rate of their blastema was different: the regeneration process was stimulated by estradiol and inhibited by testosterone. In posterior regenerants, the inhibitory effect of testosterone was also present, while estradiol had hardly any influence on the recovery rate. Both hormones significantly increased mitotic activity in the anterior and posterior regions of the regenerants. The highest mitotic index values were observed in the regions that were most remote from the cutting zone and in those immediately adjacent to it. As a working hypothesis, it is proposed that specific effects of either hormone were related to the formation of specific hormone–receptor complexes and to the pattern of hormone receptor distribution in the proximal and distal regions of the planarian body.

A significant need exists today to develop novel alternatives to traditional bone grafts. Here, we report the potential use of mechanochemically synthesized hydroxyapatite (HA), silicate-, or strontium-containing HA microparticles and microparticle aggregates in combination with polycaprolactone (PCL) as hybrid scaffolds for filling bone defects. The detailed characterization of scaffolds was performed with high-resolution synchrotron radiation–based microcomputed laminography, XRD, EDX, and FTIR. An in vitro cell-scaffold interaction analysis showed a significant improvement of cell spreading in the case of hybrid scaffolds with silicate- and Sr-containing HA. Scaffolds with Sr- and silicate-containing HA affected the expression of several genes involved in morphogenesis and transcription. Scaffolds with Sr-containing HA increased the expression of markers of the primary component of the extracellular matrix, and scaffolds with Sr-containing HA facilitated cell mineralization via an increase in osteocalcin production. The hybrid scaffolds with silicate- and Sr-containing HA microparticles exerted the highest antibacterial activity against gram-positive bacterium Staphylococcus aureus compared to the unmodified PCL scaffolds. Based on these findings, the obtained scaffolds with Sr- or silicate-containing HA are believed to hold promise for bone tissue regeneration as compared to scaffolds containing pure HA.

Molecular complexes [Zn(caf)(H2O)I2] (I), [Zn(caf)(H2O)Cl2] (IV), and the polymeric ones {[Cd(H2O)2I2](caf).2H2O}n (II) and {[Cd(H2O)2Br2](caf).2H2O}n (III) consisting of infinite Cd-containing chains with bridging halide ions and water molecules in trans-position and connected with each other due to hydrogen bonding with participation of caffeine (caf) and water molecules, were prepared and characterized by the powder and single crystal X-ray diffraction, IR vibrational spectroscopy, 1H NMR, ESI-MS spectroscopy, thermal analysis and DFT calculations. It was found that the complexes (I) and (IV) are characterized by tetrahedral geometry, the caffeine molecule being coordinated by the central atom via its N9 atom. The preferability of complex formation was evaluated by quantum-chemical calculations. Cyto- and genotoxicity of the compounds have been investigated and discussed in comparison with that of [Zn(AP)2I2] (1) and [Cd(AP)6][Cd(AP)I3]2 (2). It was demonstrated that the prepared complexes, primarily that of cadmium iodide with caffeine (II), are the promising ones for further studies both in vitro and in vivo.

The antimicrobial, anti-inflammatory and tissue-stimulating effects of cold argon atmospheric plasma (CAAP) accelerate its use in various fields of medicine. Here, we investigated the effects of CAAP at different radiation doses on mesenchymal stem cells (MSCs) and human osteosarcoma (MNNG/HOS) cells. We observed an increase in the growth rate of MSCs at sufficiently low irradiation doses (10–15 min) of CAAP, while the growth of MNNG/HOS cells was slowed down to 41% at the same irradiation doses. Using flow cytometry, we found that these effects are associated with cell cycle arrest and extended death of cancer cells by necrosis. Reactive oxygen species (ROS) formation was detected in both types of cells after 15 min of CAAP treatment. Evaluation of the genes’ transcriptional activity showed that exposure to low doses of CAAP activates the expression of genes responsible for proliferation, DNA replication, and transition between phases of the cell cycle in MSCs. There was a decrease in the transcriptional activity of most of the studied genes in MNNG/HOS osteosarcoma cancer cells. However, increased transcription of osteogenic differentiation genes was observed in normal and cancer cells. The selective effects of low and high doses of CAAP treatment on cancer and normal cells that we found can be considered in terms of hormesis. The low dose of cold argon plasma irradiation stimulated the vital processes in stem cells due to the slight generation of reactive oxygen species. In cancer cells, the same doses evidently lead to the formation of oxidative stress, which was accompanied by a proliferation inhibition and cell death. The differences in the cancer and normal cells’ responses are probably due to different sensitivity to exogenous oxidative stress. Such a selective effect of CAAP action can be used in the combined therapy of oncological diseases such as skin neoplasms, or for the removal of remaining cancer cells after surgical removal of a tumor.

A technique for the fabrication of bacterial cellulose-based films with CeO2 nanofiller has been developed. The structural and morphological characteristics of the materials have been studied, their thermal and mechanical properties in dry and swollen states having been determined. The preparation methodology makes it possible to obtain composites with a uniform distribution of nanoparticles. The catalytic effect of ceria, regarding the thermal oxidative destruction of cellulose, has been confirmed by TGA and DTA methods. An increase in CeO2 content led to an increase in the elastic modulus (a 1.27-fold increase caused by the introduction of 5 wt.% of the nanofiller into the polymer) and strength of the films. This effect is explained by the formation of additional links between polymer macro-chains via the nanoparticles’ surface. The materials fabricated were characterized by a limited ability to swell in water. Swelling caused a 20- to 30-fold reduction in the stiffness of the material, the mechanical properties of the films in a swollen state remaining germane to their practical use. The application of the composite films in cell engineering as substrates for the stem cells’ proliferation has been studied. The increase in CeO2 content in the films enhanced the proliferative activity of embryonic mouse stem cells. The cells cultured on the scaffold containing 5 wt.% of ceria demonstrated increased cell survival and migration activity. An analysis of gene expression confirmed improved cultivation conditions on CeO2-containing scaffolds.

A technique of fabrication of bacterial cellulose-based films with CeO2 nanofiller has been developed. The structural and morphological characteristics of the materials have been studied, their thermal and mechanical properties in dry and swollen states having been determined. The preparation methodology gives way to obtaining composites with the uniform distribution of nanoparticles. The catalytic effect of ceria regarding thermal oxidative destruction of cellulose was confirmed by TGA and DTA methods. An increase in CeO2 content leads to a rise in the elastic modulus (1.27-fold rise caused by the introduction of 5 wt.% of the nanofiller into polymer) and strength of the films. This effect is explained by the formation of additional links between polymer macro-chains via the nanoparticles’ surface. The materials fabricated are characterized by a limited swellability in water. Swelling causes a 20-30-fold drop in the stiffness of the material, the mechanical properties of the films in a swollen state remaining germane to their practical use. The application of the composite films in cell engineering as substrates for the stem cells proliferation has been studied. The increase in CeO2 content in the films enhanced the proliferative activity of embryonic mouse stem cells. The cells cultured on the scaffold containing 5 wt.% of ceria demonstrated increased cell survival and migration activity. Analysis of gene expression confirmed the improved cultivation conditions on CeO2-containing scaffolds.

Cerium oxide nanoparticles (nanoceria) are regarded as one of the most promising inorganic antioxidants for biomedical applications. Considering nanoceria as a potential therapeutic agent, we aimed to develop a robust system for its intracellular delivery using layer-by-layer polyelectrolyte microcapsules. We have shown that citrate-stabilized cerium oxide nanoparticles can be effectively incorporated into the structure of polyelectrolyte microcapsules made from biodegradable and nonbiodegradable polymers. The structure and morphology of synthesized microcapsules were investigated and analyzed using confocal laser scanning microscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and UV/vis spectroscopy. Results of experiments in vitro on B50 neuroblastoma cells confirmed nanoceria delivery into the cell while maintaining their antioxidant properties. The results presented confirm polyelectrolyte microcapsules to be an efficient intracellular delivery system for therapeutic nanoparticles.

The results of studies into microporous scaffolds based on polycaprolactone, in particular, involving nanoparticles and microparticles of modified (silicon-containing) hydroxyapatite (hybrid scaffolds) are presented. When hydroxyapatite particles are used during the electrospinning of polymer scaffolds, their porosity is found to increase substantially and a structure with nanofibers and microfibers can be created. X-ray phase analysis demonstrates that the characteristic lines of polycaprolactone and hydroxyapatite exist in the 3D hybrid scaffold structure. According to the data of infrared (IR) spectroscopy of the hydroxyapatitepowder precursor, (SiO4)4– ions are embedded in its lattice. The results of studies into the surface wettability indicate that the contact angles of wetting with water are smaller for hybrid scaffolds than for pure polycaprolactone scaffolds. Adhesive and proliferative activity tests of human mesenchymal stem cells (MSCs) performed upon hybrid-scaffold cultivation on the surface, as well as histologic investigations, indicate the high biocompatibility of the samples. On the basis of a polymerase chain reaction, it is revealed that the differentiation of MSCs occurs in the osteogenic direction. On account of a porous structure, hybrid scaffolds can be employed to recover bone-tissue defects.

Cerium oxide nanoparticles (nanoceria) are regarded as one of the most promising inorganic antioxidants for biomedical applications. Considering nanoceria as a potential therapeutic agent, we aimed to develop a robust system for its intracellular delivery using layer-by-layer polyelectrolyte microcapsules. We have shown that citrate-stabilized cerium oxide nanoparticles can be effectively incorporated into the structure of polyelectrolyte microcapsules made from biodegradable and nonbiodegradable polymers. The structure and morphology of synthesized microcapsules were investigated and analyzed using confocal laser scanning microscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and UV/vis spectroscopy. Results of experiments in vitro on B50 neuroblastoma cells confirmed nanoceria delivery into the cell while maintaining their antioxidant properties. The results presented confirm polyelectrolyte microcapsules to be an efficient intracellular deliver...

The study is dedicated to the investigation of serotonin (5-hydroxytryptamine, 5-HT) and 5-HT7 type serotonin receptor of localisation in larvae of two parasitic flatworms Opisthorchis felineus (Rivolta, 1884) Blanchard, 1895 and Hymenolepis diminuta Rudolphi, 1819, performed using the immunocytochemical method and confocal laser scanning microscopy (CLSM). Using whole mount preparations and specific antibodies, a microscopic analysis of the spatial distribution of 5-HT7-immunoreactivity(-IR) was revealed in worm tissue. In metacercariae of O. felineus 5-HT7-IR was observed in the main nerve cords and in the head commissure connecting the head ganglia. The presence of 5-HT7-IR was also found in several structures located on the oral sucker. 5-HT7-IR was evident in the round glandular cells scattered throughout the larva body. In cysticercoids of H. diminuta immunostaining to 5-HT7 was found in flame cells of the excretory system. Weak staining to 5-HT7 was observed along the longitudinal and transverse muscle fibres comprising the body wall and musculature of suckers, in thin longitudinal nerve cords and a connective commissure of the central nervous system. Available publications on serotonin action in flatworms and serotonin receptors identification were reviewed. Own results and the published data indicate that the muscular structures of flatworms are deeply supplied by 5-HT7-IR elements. It suggests that the 5-HT7 type receptor can mediate the serotonin action in the investigated species and is an important component of the flatworm motor control system. The study of the neurochemical basis of parasitic flatworms can play an important role in the solution of fundamental problems in early development of the nervous system and the evolution of neuronal signalling components.

Planarian freshwater flatworms have the unique ability to regenerate due to stem cell activity. The process of regeneration is extremely sensitive to various factors, including light radiation. Here, the effect of low-intensity LED light of different wavelengths on regeneration, stem cell proliferation and gene expression associated with these processes was studied. LED matrices with different wavelengths (red (λmax = 635 nm), green (λmax = 520 nm) and blue (λmax = 463 nm), as well as LED laser diodes (red (λmax = 638.5 nm), green (λmax = 533 nm) and blue (λmax = 420 nm), were used in the experiments. Computer-assisted morphometry, whole-mount immunocytochemical study and RT-PCR were used to analyze the biological effects of LED light exposure on the planarian regeneration in vivo. It was found that a one-time exposure of regenerating planarians with low-intensity red light diodes stimulated head blastema growth in a dose-dependent manner (up to 40%). The green light exposure of planarians resulted in the opposite effect, showing a reduced head blastema growth rate by up to 21%. The blue light exposure did not lead to any changes in the rate of head blastema growth. The maximum effects of light exposure were observed at a dose of 175.2 mJ/cm2. No significant differences were revealed in the dynamics of neoblasts' (planarian stem cells) proliferation under red and green light exposure. However, the RT-PCR gene expression analysis of 46 wound-induced genes revealed their up-regulation upon red LED light exposure, and down-regulation upon green light exposure. Thus, we have demonstrated that the planarian regeneration process is rather sensitive to the effects of low-intensity light radiation of certain wavelengths, the biological activity of red and green light being dictated by the different expression of the genes regulating transcriptional activity.

Cerium oxide (CeO2) nanoparticles are regarded as one of the most promising materials for biomedical applications. Due to their antioxidant activity CeO2 nanoparticles are capable of protecting cells from oxidative stress induced by various physical or chemical factors. In this paper we have investigated the protective effect of CeO2 nanoparticles in the model of oxidative stress induced by low-temperature argon plasma, which is characterized by multiply damaging factors, including different types of radiation (ultraviolet and infrared), free radicals and reactive oxygen species. It was shown that citrate-stabilized cerium oxide nanoparticles protect primary embryonic mouse fibroblasts from the action of plasma, maintaining a high level of cell viability.

One of the main reasons for limiting the widespread clinical use of mesenchymal stem cells (MSCs) is a low speed of their proliferation in vitro. In this regard, the search for new safe and effective growth stimulants is an urgent task. In this study, we investigated the effect of nanocrystalline cerium oxide doped with gadolinium (Ce1-х Gdх Oy), on the morphofunctional characteristics and proliferative activity of MSCs derived from dental pulp. It was shown that the introduction of Ce1-х Gdх Oy nanoparticles into the culture of dental MSCs provides the activation of proliferation of the cells in a dose-dependent manner. High concentrations of Ce1-х Gdх Oy nanoparticles inhibit the proliferation of the cells; however, this does not lead to further development of apoptosis and cell death. The obtained results indicate that the nanocrystalline cerium oxide can be considered as a basis for the development of highly efficient and low-cost supplements for culturing MSCs.

It has been shown that a single low-intensity (0.146 mW/cm2) irradiation of a cell culture of human fetal fibroblasts by a red LED (λmax = 635 nm) at a dose of 175.2 mJ/cm2 led to a slight stimulation of culture growth, whereas light irradiation by a green LED (λmax = 520 nm) at the same dose did not alter the proliferative activity of cultured fibroblasts. The growth of transformed MNNG/hos cells did not change at the selected irradiation modes. Both types of irradiation changed the expression profile of the proliferation and osteogenic differentiation genes of the fibroblast culture. In the transformed MNNG/hos cells, the red light promoted the expression of stemness genes, osteogenic differentiation genes, and cell-death markers. The transcription activity of cell-death markers and checkpoints in the MNNG/hos cells increased under the influence of the green light.

This study aimed to delineate the infecting micro-organisms identified at the first-time revision for infected THA, analyze pre-operative versus intra-operative findings, as well as intra-operative ones against re-infection micro-organisms. Microbiological laboratory findings were studied in 73 patients (mean age, 51.93 ± 10.9 years) with chronic periprosthetic hip infection pre-operatively and intra-operatively. Forty-three patients had a two-stage revision THA while 30 patients were treated with a modified resection arthroplasty using the Ilizarov apparatus. Re-infection developed in 29 cases. Its microbial species were identified. Pre-operative findings on micro-organisms coincided 50.7 % with the intra-operative ones. Bacterial growth in the intra-operative tests was detected in 72 (98.5 %) cases. Gram-positive single genus infection was identified in 35 patients (48 %); microbe associations were present in 33 patients (45 %). Staphylococcus species prevailed. Gram-negative infection was detected in 5.5 % of cases. One case (1.5 %) did not have any microbe growth. Re-infection happened in 10 cases (23.2 %) in a two-stage revision THA. In the resection arthroplasty group, early re-infection was observed in 63.3 % of cases. Among a total of 29 re-infection cases, staphylococcus species were identified in 19 cases, present either in associations or as single germs. Intra-operative microbiological tests at the first-time revision for infected THR detect a reliable spectrum of micro-organisms to assess microbial resistance to antibiotics, develop treatment protocols, and for prognostic purposes. Preventive measures at primary THR and strategies to fight periprosthetic infection and reinfection should be targeted on staphylococci.

Background: Resection arthroplasty or hip arthrodesis after total hip replacement (THR) can be used to salvage the limb in case with deep infection and severe bone loss. The Ilizarov fixator provides stability, axial correction, weight-bearing and good fusion rates. Materials and Methods: We retrospectively assessed the outcomes of 37 patients with severe periprosthetic infection after THR treated between 1999 and 2011. The treatment included implant removal, debridement and a modified Girdestone arthroplasty (29 cases) or hip arthrodesis (seven cases) using the Ilizarov fixator. The Ilizarov fixation continued from 45 to 50 days in the modified arthroplasty group and 90 days in the arthrodesis group. One case was treated using the conventional resection arthroplasty bilaterally. Results: Eighteen months after treatment, infection control was seen in 97.3% cases. Six hips were fused as one patient died in this group. Limb length discrepancy (LLD) averaged 5.5 cm. The Harris hip score ranged from 35 to 92 points. Hip joint motion ranged from 10° to 30° in the modified arthroplasty group. All subjects could walk independently or using support aids. No subluxation or LLD progression was observed. Conclusion: The modified Girdlestone arthroplasty and hip arthrodesis using the Ilizarov apparatus results in sufficient ability for ambulation and good infection control in cases of failed THR associated with severe infection.

Cerium oxide nanoparticles (nanoceria) are believed to be the most versatile nanozyme, showing great promise for biomedical applications. At the same time, the controlled intracellular delivery of nanoceria remains an unresolved problem. Here, we have demonstrated the radioprotective effect of polyelectrolyte microcapsules modified with cerium oxide nanoparticles, which provide controlled loading and intracellular release. The optimal (both safe and uptake efficient) concentrations of ceria-containing microcapsules for human mesenchymal stem cells range from 1:10 to 1:20 cell-to-capsules ratio. We have revealed the molecular mechanisms of nanoceria radioprotective action on mesenchymal stem cells by assessing the level of intracellular reactive oxygen species (ROS), as well as by a detailed 96-genes expression analysis, featuring genes responsible for oxidative stress, mitochondrial metabolism, apoptosis, inflammation etc. Hybrid ceria-containing microcapsules have been shown to provide an indirect genoprotective effect, reducing the number of cytogenetic damages in irradiated cells. These findings give new insight into cerium oxide nanoparticles&rsquo, protective action for living beings against ionising radiation.

Photochromic tungsten oxide (WO3) nanoparticles stabilized by polyvinylpyrrolidone (PVP) were synthesized to evaluate their potential for biomedical applications. PVP-stabilized tungsten oxide nanoparticles demonstrated a highly selective cytotoxic effect on normal and cancer cells in vitro. WO3 nanoparticles were found to induce substantial cell death in osteosarcoma cells (MNNG/HOS cell line) with a half-maximal inhibitory concentration (IC50) of 5 mg/mL, while producing no, or only minor, toxicity in healthy human mesenchymal stem cells (hMSc). WO3 nanoparticles induced intracellular oxidative stress, which led to apoptosis type cell death. The selective anti-cancer effects of WO3 nanoparticles are due to the pH sensitivity of tungsten oxide and its capability of reactive oxygen species (ROS) generation, which is expressed in the modulation of genes involved in reactive oxygen species metabolism, mitochondrial dysfunction, and apoptosis.

Polyetheretherketone (PEEK) is an alternative to metallic implants and a material of choice in many applications, including orthopedic, spinal, trauma, and dental. While titanium (Ti) and Ti-alloys are widely used in many intraosseous implants due to its biocompatibility and ability to osseointegrate, negatives include stiffness which contributes to shear stress, radio-opacity, and Ti-sensitivity. Many surgeons prefer to use PEEK due to its biocompatibility, similar elasticity to bone, and radiolucency, however, due to its inert properties, it fails to fully integrate with bone. Accelerated Neutral Atom Beam (ANAB) technology has been successfully employed to demonstrate enhanced bioactivity of PEEK both in vitro and in vivo. In this study, we further characterize surfaces of PEEK modified by ANAB as well as elucidate attachment and genetic effects of dental pulp stem cells (DPSC) exposed to these surfaces. ANAB modification resulted in decreased contact angle at 72.9 ± 4.5° as compared to 92.4 ± 8.5° for control (p, Graphical abstract Image 1, Highlights • PEEK is a material of choice for biomaterials except that it is inert and does not integrate with bone. • Neutral atom beam technology (ANAB) is a surface modification technique that modifies the surface at a nano-scale level and makes the surface more hydrophilic. • Increased cell attachment and proliferation is seen on ANAB-treated PEEK. • Dental pulp stem cells differentiate towards osteoblast when grown on ANAB-treated PEEK. • ANAB makes PEEK bioactive.

We report the first experimental evidence for the mitogenic action of cerium(IV) oxide and cerium(III) fluoride nanoparticles (CONs and CFNs) on the regeneration of a whole organism – freshwater flatworms Schmidtea mediterranea (planarian). Both types of cerium-containing nanoparticles are shown to be a highly potent mitogen for planaria. Both CONs and CFNs, in micro- and nanomolar concentrations, markedly accelerate planarian blastema growth, due to the enhancement of cellular proliferation, causing an increase in the mitotic index and in the quantity of blastema cells in regenerating planaria. CONs provided maximum activity at concentrations which were two orders of magnitude lower than those for CeF3. The valence state of cerium in cerium-containing nanoparticles plays a significant role in the planarian regeneration mechanism: CeO2 nanoparticles containing predominantly Ce4+ species presumably scavenge wound induced reactive oxygen species and moderately activate gene expression processes, while the regenerative action of CeF3 nanoparticles containing only Ce3+ species is manifested in the pronounced expression of the genes involved in cell division, differentiation and migration. This is the first report on the effect of cerium-containing nanoparticles on tissue regeneration in vivo, further revealing the mechanisms of their biological action, which enhances the possibility of their use in cellular technologies.

The stem cells in freshwater flatworms (planarian) are called neoblasts. Neoblasts are capable of proliferation and differentiation into every cell type, including the gametes. For the investigation of the mechanisms of stem cells proliferation and differentiation the proper evaluation of changes in the cell cycle of neoblasts in different physiological conditions of planarian is necessary. In the present study the possibility of qualitative and quantitative characteristics of the neoblasts population were investigated using flow cytometry. In the cell suspension prepared from planarian tissue proliferating neoblasts have been observed in heterogenic cell population. Quantitative estimation of the cell cycle related changes of planarian stem cells system have been performed in various physiological conditions (intact and regenerating animals) and under the influence of physical (ionizing radiation) and chemical (melatonin and colchicine) factors. The modified protocol for planarian stem cells isolation proved to be effective and reproducible and can be recommended for flow cytometry analyses of human and animal proliferating cells.