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Titanium and its alloys are widely used in medicine thanks to their favorable physical, chemical properties and relatively good biocompatibility with human cells and tissues. A serious disadvantage of titanium alloys is the metal ions release in contact with body fluids and their penetration into the surrounding biological environment. So as to limit the corrosion and diffusion of its products and improve the implant-bone integration, the metallic substrate is covered with protective layers. One of the methods of applying coatings is the sol–gel technique which allows the incorporation of antimicrobial ingredients into a pure silica matrix. The aim of the study was to assess the stability of hybrid coatings on a titanium substrate during long-term incubation in distilled water and in systemic conditions. The surface properties of the modified TiAlV substrates, i.e., roughness, wettability, and surface energy, were investigated. The chemical stability of the layers in in vitro and ex vivo SEM-EDS and FTIR conditions was also analyzed. For 90 days, a decrease in the contact angle and the roughness increase were observed. The obtained results correlated with the bands intensity decrease in the FTIR spectrum, which confirmed the degradation of the obtained layers in the aqueous environment. [ABSTRACT FROM AUTHOR]

Presented paper contains description and interpretation of the results of selected physicochemical and structural properties of two types of composite sinters. They were constituted of a mixture of sintered microcrystalline corundum and bioglass CaO-P2O5-SiO2-Na2O system intended for scaffolds to cell culture of human chondrocytes. The composites contained a mixture of both above-mentioned components in the volumetric proportion of 50:50 (W5) and 30:70 (W7). They were obtained using powder metallurgy by free sintering in air atmosphere. Phase analysis of composites and verification of theoretical identification using X-ray diffraction were performed. The same phases were found in both cases (Al2O3 SiO2 CaAl2Si2O8, Ca3 (PO4)2, Ca2Al4O7 and NaAlSiO4). Microscopic tests of composite surfaces were performed and some differences were found. W5 sample was not completely covered with bioglass, whilst W7 sample was completely covered with bioglass with few fine pores. Tests of surface topography confirmed the presence of large and small pores. Composite surfaces immersed for 30 days in artificial blood plasma were tested and then electron microscopy analysis was performed. It was found that no significant changes occurred on the surface of the W5 composite, probably partial corrosion of the glass happened. Spherical forms characteristic of HA-hydroxyapatites were observed on the surface of sample W7. Human articular chondrocyte cells were seeded on both types of sinters and proliferation assay was performed. Results indicate that tested scaffolds support cellular attachment and proliferation of chondrocytes. [ABSTRACT FROM AUTHOR]

In this work we dissected the osteoinductive properties of selected, PLGA-based scaffolds enriched with gel-derived bioactive glasses (SBGs) of either binary SiO2-CaO or ternary SiO2-CaO-P2O5 system, differing in CaO/SiO2 ratio (i.e. high -or low-calcium SBGs). To assess the inherent ability of the scaffolds to induce osteogenesis of human bone marrow stromal cells (BMSC), the study was designed to avoid any osteogenic stimuli beyond the putative osteogenic SBG component of the studied scaffolds. The bioactivity and porosity of scaffolds were confirmed by SBF test and porosimetry. Condition media (CM) from BMSC-loaded scaffolds exhibited increased Ca and decreased P content corresponding to SBGs CaO/SiO2 ratio, whereas Si content was relatively stable and overall lower in CM from scaffolds containing binary SBGs. CM from cell-loaded scaffolds containing high-calcium, binary SBGs promoted migration of BMSC and BMP-response in reporter osteoblast cell line. BMSC culture on these scaffolds or the ones containing ternary, low-calcium SBGs resulted in the activation of BMP-related signaling and expression of several osteogenic markers. Ectopic bone formation was induced by scaffolds containing binary SBGs, but high-calcium ones produced significantly more osteoid. Scaffolds containing ternary SBGs negatively influenced the expression of osteogenic transcription factors and Cx43, involved in cell-cell interactions. High-calcium scaffolds stimulated overall higher Cx43 expression. We believe the initial cell-cell communication may be crucial to induce and maintain osteogenesis and high BMP signaling on the studied scaffolds. The presented scaffolds' biological properties may also constitute new helpful markers to predict osteoinductive potential of other bioactive implant materials. [ABSTRACT FROM AUTHOR]

Background and purpose: Delirium is a very common neurobehavioral complication after stroke, but its influence on long-term outcome is not well characterized. The objective of the study was to determine the prognostic significance of delirium for functional status, nursing home admission, and mortality in a large cohort of patients with delirium in the acute phase of stroke assessed 3 and 12 months after stroke. Methods: All stroke survivors included in PROPOLIS were followed up (n = 682). Outcome data included: discharge destination, recurrence of stroke, cardiovascular complications, functional activity and mobility, nursing home admission, and mortality. Results: Patients with delirium were discharged to another hospital or nursing home significantly more often than those presenting without delirium. The 3- and 12-month post-stroke mortality rates were higher in delirious patients (OR 6.41 CI 3.76–10.92; p < 0.001 and OR 5.17 CI 3.36–7.96; p < 0.001). When considering 3-month mortality, higher age, modified Rankin Scale prior to admission and temperature between 1 and 3 days after admission, as well delirium, pneumonia and more severe neurological deficits on admission were independent risk factors. For 12-month mortality, the independent risk factors were higher age and modified Rankin Scale post-stroke, delirium, and history of respiratory diseases prior to stroke. Patients with delirium were more likely to live in nursing homes 3 and 12 months after stroke and were more disabled than patients without delirium. Conclusions: Delirium in acute phase of stroke negatively influences the long-term prognosis. A study addressing the effect of early recognition and treatment of identified modifiable risk factors for adverse long-term outcomes is urgently needed to decrease bad prognosis within this population. [ABSTRACT FROM AUTHOR]

The ability to measure and control the composition of activated sludge is an important issue, aiming at evaluating the effectiveness of changes occurring in the sludge, what determines its usefulness to treat wastewater. In this research, diffuse reflectance infrared Fourier transform (FTIR-DRIFT) technique was used, which relies on measuring the reflectance of the powdered substance’s surface layer and capturing spectra in range of infrared wave. First, spectra correlation table of the substances mostly occurring in wastewater was developed to assess the main components of the tested samples of activated sludge. The simplest compounds containing functional groups characteristic for particular chemical classes were chosen: peptides (peptone and albumin), fats (glycerin and fatty acids), carbohydrates (glucose and sucrose), nitrogen compounds (NaNO3 and NH4SO4), sulfur compounds (Na2SO4 and Na2S2O3), silicate, etc. The spectra of those substances were captured and characteristic absorption bands for respective bonds in the function groups were assigned. Second, samples of activated sludge from lab-scale membrane bioreactors (MBRs), which purifies petroleum wastewater, were taken. Samples were properly prepared (lyophilization and homogenization) and their spectra were captured. During spectra analysis, previously developed correlation table was used. In obtained spectra of activated sludge, absorption bonds characteristic for amides, peptides, carbohydrates, fats, and aliphatic was identified. The spectra profile of the sludge sample from MBR feed with petroleum wastewater was slightly different from the control MBR sample’s spectra. Intensity of bands in the area characteristic for aliphatic compounds and phenols was clearly higher. This study proves the usefulness of FT-IR technique to observe changes in the chemical composition of activated sludge. [ABSTRACT FROM AUTHOR]

In the present work, the role of content, size and chemical composition of gel-derived bioactive glass particles from the SiO-CaO-PO system in modulating the in vitro bioactivity, osteoinductive properties and long-term (up to 15 months) degradation behaviour of poly(ε-caprolactone)-based composite films was investigated. Bioactivity was assessed in simulated body fluid (SBF) and HEPES-free Dulbecco's modified Eagle medium (DMEM) supplemented with 10% foetal bovine serum (FBS), while hydrolytic degradation tests were performed in phosphate buffer saline. Obtained composite films showed excellent calcium phosphate (CaP) layer forming ability in both SBF and DMEM-10% FBS. However, kinetics of bioactivity process strongly depended on the type of medium used. The layer of amino acids and proteins, derived from cell culture medium, on the surfaces of composites created barrier that inhibited release of the ions on the one hand, while increasing nucleation density of calcium phosphates, affecting the morphology of formed CaP layers on the other. The presence of bioactive glass fillers was shown to impart osteoinductive properties to obtained films, supporting osteoblast attachment and proliferation, as well as stimulating cell differentiation and also matrix mineralization process in vitro. We showed that kinetics of bioactivity process and also osteoinductive properties of composite films could be easily modulated with the use of different contents and chemical compositions of fillers. The results showed that modification of PCL matrix with bioactive glass particles accelerated its degradation. We proved that the degradation rate of composites could be controlled and optimized for bone regeneration, in particular by using bioactive fillers causing different calcium phosphate layer forming ability on the surfaces of composites, depending on particle size and chemical composition. We have presented new opportunities to design and obtain multifunctional composites with tunable degradation and bioactivity kinetics, as well as biological properties that can meet complex requirements of bone tissue engineering. [ABSTRACT FROM AUTHOR]

In contrast to currently used materials, membranes for the treatment of bone defects should actively promote regeneration of bone tissue beyond their physical barrier function. What is more, both material properties and biological features of membranes should be easily adaptable to meet the needs of particular therapeutic applications. Therefore, the role of preparation methods (non-solvent-induced phase separation and thermal-induced phase separation) of poly(ε-caprolactone)-based membranes and their modification with gel-derived bioactive glass (BG) particles of two different sizes (<45 and <3 μm) in modulating material morphology, polymer matrix crystallinity, surface wettability, kinetics of in vitro bioactivity and also osteoblast response was investigated. Both surfaces of membranes were characterised in terms of their properties. Our results indicated a possibility to modulate microstructure (pore size ranging from submicron to hundreds of micrometres), wettability (from hydrophobic to fully wettable surface) and polymer crystallinity (from 19 to 60%) in a wide range by the use of various preparation methods and different BG particle sizes. Obtained composite membranes showed excellent in vitro hydroxyapatite forming ability after incubation in simulated body fluid. Here we demonstrated that bioactive layer formation on the surface of membranes occurred through ACP-OCP-CDHA-HCA transformation, that mimic in vivo bone biomineralization process. Composite membranes supported human osteoblast proliferation, stimulated cell differentiation and matrix mineralization. We proved that kinetics of bioactivity process and also osteoinductive properties of membranes can be easily modulated with the use of proposed variables. This brings new opportunities to obtain multifunctional membranes for bone regeneration with tunable physicochemical and biological properties. [ABSTRACT FROM AUTHOR]

In this study, microporous composite sol-gel glass/polyetheretherketone (SGG/PEEK) coatings were produced on the Ti-13Nb-13Zr titanium alloy by electrophoretic deposition. Coatings with different levels of high open porosity were developed by introducing SGG particles of varying diameters into the PEEK matrix. The microstructure of the coatings was characterized by electron microscopy and X-ray diffractometry. The coatings with 40-50 µm thickness were composed of semicrystalline SGG particles consisting of hydroxyapatite, CaSiO, some CaSiO, and an amorphous phase containing Ca, Si, P, and O, homogeneously embedded in a semicrystalline PEEK matrix. The size of SGG particles present in the coatings strongly influenced the formation of microcracks and their adhesion to the underlying substrate. Microscratch tests showed that the coating containing SGG particles with a diameter smaller than 45 µm and open porosity of 45 pct exhibited good adhesion to the titanium alloy substrate, much better than the coating containing particles with a diameter smaller than 85 µm and total open porosity equal to 48 pct. The corrosion resistance was investigated in Ringer's solution at a temperature of 310 K (37 °C) for a pH equal to 7.4 and in deaerated solutions with the use of open-circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy. The SGG/PEEK-coated alloy indicated better electrochemical corrosion resistance compared with the uncoated alloy. [ABSTRACT FROM AUTHOR]

Atherosclerosis commonly affects the arteries harvested from patients 70 years of age or older. Saphenous vein grafts appear to maintain a higher patency rate after coronary artery bypass grafting in these subjects. The infiltration of macrophages is an early step in saphenous vein graft atherosclerosis; however, little is known regarding the underlying mechanisms of infiltration. The objective of the present report is to evaluate the presence of CD68-positive cells in the saphenous vein wall and correlate initial CD68-positive infiltration to specific clinical and biochemical parameters and the graft patency rate as estimated in patients undergoing coronary artery bypass grafting. A total of 309 patients were allocated into two groups: A1 patients, who were between 50 and 70 years of age, and A2 patients, who were 70 years or older at the time of vein harvesting. CD68 expression was evaluated by immunohistochemistry. There were no significant differences between A1 and A2 patients regarding macrophage expression within any of the analyzed vascular regions. Saphenous vein macrophages were never present in the tunica intima unless they were also expressed in the media or the adventitia. The patients with CD68-positive cells in the tunica intima had a significantly higher number of bypass stenoses when compared with the subjects who did not have CD68-positive cells in this layer. These findings suggest that the CD68-positive cells (those that have not yet developed into foam cells) present in the intima of saphenous vein grafts might serve as a very early marker of graft occlusion. [ABSTRACT FROM AUTHOR]

We have developed poly( l-lactide- co-glycolide) (PLGA) based composites using sol-gel derived bioactive glasses (S-BG), previously described by our group, as composite components. Two different composite types were manufactured that contained either S2-high content silica S-BG, or A2-high content lime S-BG. The composites were evaluated in the form of sheets and 3D scaffolds. Sheets containing 12, 21, and 33 vol.% of each bioactive glass were characterized for mechanical properties, wettability, hydrolytic degradation, and surface bioactivity. Sheets containing A2 S-BG rapidly formed a hydroxyapatite surface layer after incubation in simulated body fluid. The incorporation of either S-BG increased the tensile strength and Young's modulus of the composites and tailored their degradation rates compared to starting compounds. Sheets and 3D scaffolds were evaluated for their ability to support growth of human bone marrow cells (BMC) and MG-63 cells, respectively. Cells were grown in non-differentiating, osteogenic or osteoclast-inducing conditions. Osteogenesis was induced with either recombinant human BMP-2 or dexamethasone, and osteoclast formation with M-CSF. BMC viability was lower at higher S-BG content, though specific ALP/cell was significantly higher on PLGA/A2-33 composites. Composites containing S2 S-BG enhanced calcification of extracellular matrix by BMC, whereas incorporation of A2 S-BG in the composites promoted osteoclast formation from BMC. MG-63 osteoblast-like cells seeded in porous scaffolds containing S2 maintained viability and secreted collagen and calcium throughout the scaffolds. Overall, the presented data show functional versatility of the composites studied and indicate their potential to design a wide variety of implant materials differing in physico-chemical properties and biological applications. We propose these sol-gel derived bioactive glass-PLGA composites may prove excellent potential orthopedic and dental biomaterials supporting bone formation and remodeling. [ABSTRACT FROM AUTHOR]

Structural alterations in thymuses of female rats during the first 2 years of life were evaluated by morphometric analysis and, then, correlated with organization of epithelial cells in various thymic compartments, examined for their cytokeratin immunoreactivity. With an advancing age, the thymuses demonstrated morphological modifications related to maturation and senescence, the dynamics of which varied between particular thymic compartments, and involved subpopulations of thymic epithelial cells. In the entire period of life the most dynamic changes were found in the cortex while the medulla was demonstrated to be a rather “stable” region. Morphometric studies revealed a negative correlation between the volume of thymic cortex and medulla and age of rats and a linear, positive relationship between the volume of connective tissue compartment and age. Changes in organization of epithelial network in the medulla preceded those observed in the cortex. Decreased proliferative activity of subset of medullary cells, which probably represented a self-renewable population, was accompanied by alterations in the immunocytochemically characterized (cytokeratines) differentiation process. At the same period of life, hypertrophy and hyperplasia of superficial epithelial cells seems to functionally replace medullary cells. This process begins around 3rd month of life and expands on all thymic compartments. The first changes in the cortex appeared around 8th month and were connected with reduced cytokeratin immunoreactivity. The involution observed in older animals was preceded by age-related alterations in epithelial network pattern which, in the course of stable morphometric parameters (between 5th and 12th month), showed character of a structural and functional adaptation. [ABSTRACT FROM AUTHOR]

In this work, composite membranes were investigated as future components of a layered implant for the reconstruction of nasal septum. Incorporation of zinc ions into nasal implants could potentially provide antibacterial properties to decrease or eliminate bacterial infections and subsequent surgical complications. Two types of membranes were prepared using an electrospinning method: PCL with bioglass and PCL with bioglass doped with Zn. The aim of this work was to investigate the influence of bioglass addition on the morphology, fiber diameter and composition of the membranes. The apatite-forming ability was examined in Simulated Body Fluid (SBF). The cytotoxicity of the membranes, ALP activity and in vitro mineralization were evaluated in cell culture. The mineralization and ALP activity was higher for polycaprolactone membranes modified with Zn doped bioglass than compared to pure PCL membranes or control material. The results proved that the presence of Zn2+ in the electrospun membranes = influence the osteogenic differentiation of cells. [ABSTRACT FROM AUTHOR]