Easy, Flexible and Standardizable Anti-Nascent Biofilm Activity Assay to Assess Implant Materials.

Medical implants have improved the quality of life of many patients. However, surgical intervention may eventually lead to implant microbial contamination. The aims of this research were to develop an easy, robust, quantitative assay to assess surface antimicrobial activities, especially the anti-nascent biofilm activity, and to identify control surfaces, allowing for international comparisons. Using new antimicrobial assays to assess the inhibition of nascent biofilm during persistent contact or after transient contact with bacteria, we show that the 5 cent Euro coin or other metal-based antibacterial coins can be used as positive controls, as more than 4 log reduction on bacterial survival was observed when using either S. aureus or P. aeruginosa as targets. The methods and controls described here could be useful to develop an easy, flexible and standardizable assay to assess relevant antimicrobial activities of new implant materials developed by industries and academics.

The process of becoming 'we' in an intergroup conflict context: How enhancing intergroup moral similarities leads to common-ingroup identity.

Research on common-ingroup identity has mainly focused on consequences and potential benefits of inclusive social categorizations. However, very little is yet known about processes and conditions that could facilitate such inclusive social categorizations. In this paper, with four studies (N = 582) set in a post-conflict context of Bosnia and Herzegovina and with members of two ethnic groups (Bosniaks and Serbs), we have demonstrated how perceptions of intergroup moral similarity can act as an important precursor of common-ingroup identity at the national level. We report both cross-sectional as well as experimental evidence demonstrating how perceptions of intergroup moral similarity boost common-ingroup identifications in socially relevant context using members of real adversary social groups. Moreover, we show that learning about outgroups' morally admirable behaviours can facilitate inclusive social categorizations.

Electrophoretic Deposition of Biocompatible and Bioactive Hydroxyapatite-Based Coatings on Titanium.

Current trends in biomaterials science address the issue of integrating artificial materials as orthopedic or dental implants with biological materials, e.g., patients' bone tissue. Problems arise due to the simple fact that any surface that promotes biointegration and facilitates osteointegration may also provide a good platform for the rapid growth of bacterial colonies. Infected implant surfaces easily lead to biofilm formation that poses a major healthcare concern since it could have destructive effects and ultimately endanger the patients' life. As of late, research has centered on designing coatings that would eliminate possible infection but neglected to aid bone mineralization. Other strategies yielded surfaces that could promote osseointegration but failed to prevent microbial susceptibility. Needless to say, in order to assure prolonged implant functionality, both coating functions are indispensable and should be addressed simultaneously. This review summarizes progress in designing multifunctional implant coatings that serve as carriers of antibacterial agents with the primary intention of inhibiting bacterial growth on the implant-tissue interface, while still promoting osseointegration.

Assessing the Bioactivity of Gentamicin-Preloaded Hydroxyapatite/Chitosan Composite Coating on Titanium Substrate.

The electrophoretic deposition process (EPD) was utilized to produce bioactive hydroxyapatite/chitosan (HAP/CS) and hydroxyapatite/chitosan/gentamicin (HAP/CS/Gent) coatings on titanium. The bioactivity of newly synthesized composite coatings was investigated in the simulated body fluid (SBF) and examined by X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The obtained results revealed carbonate-substituted hydroxyapatite after immersion in SBF, emphasizing the similarity of the biomimetically grown HAP with the naturally occurring apatite in the bone. The formation of biomimetic HAP was confirmed by electrochemical impedance spectroscopy and polarization measurements, through the decrease in corrosion current density and coating capacitance values after 28-day immersion in SBF. The osseointegration ability was further validated by measuring the alkaline phosphatase activity (ALP) indicating the favorable osseopromotive properties of deposited coatings (significant increase in ALP levels for both HAP/CS (3.206 U mL-1) and HAP/CS/Gent (4.039 U mL-1) coatings, compared to the control (0.900 U mL-1)). Drug-release kinetics was investigated in deionized water at 37 °C by high-performance liquid chromatography coupled with mass spectrometry. Release profiles revealed the beneficial "burst-release effect" (∼21% of gentamicin released in the first 48 h) as a potentially promising solution against the biofilm formation in the initial period. When tested against human and mice fibroblast cells (MRC-5 and L929), both composite coatings showed a noncytotoxic effect (viability >85%), providing a promising basis for further medical application trials.

Antibacterial graphene-based hydroxyapatite/chitosan coating with gentamicin for potential applications in bone tissue engineering.

Electrophoretic deposition process (EPD) was successfully used for obtaining graphene (Gr)-reinforced composite coating based on hydroxyapatite (HAP), chitosan (CS), and antibiotic gentamicin (Gent), from aqueous suspension. The deposition process was performed as a single step process at a constant voltage (5 V, deposition time 12 min) on pure titanium foils. The influence of graphene was examined through detailed physicochemical and biological characterization. Fourier transform infrared spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, X-ray diffraction, Raman, and X-ray photoelectron analyses confirmed the formation of composite HAP/CS/Gr and HAP/CS/Gr/Gent coatings on Ti. Obtained coatings had porous, uniform, fracture-free surfaces, suggesting strong interfacial interaction between HAP, CS, and Gr. Large specific area of graphene enabled strong bonding with chitosan, acting as nanofiller throughout the polymer matrix. Gentamicin addition strongly improved the antibacterial activity of HAP/CS/Gr/Gent coating that was confirmed by antibacterial activity kinetics in suspension and agar diffusion testing, while results indicated more pronounced antibacterial effect against Staphylococcus aureus (bactericidal, viable cells number reduction >3 logarithmic units) compared to Escherichia coli (bacteriostatic, <3 logarithmic units). MTT assay indicated low cytotoxicity (75% cell viability) against MRC-5 and L929 (70% cell viability) tested cell lines, indicating good biocompatibility of HAP/CS/Gr/Gent coating. Therefore, electrodeposited HAP/CS/Gr/Gent coating on Ti can be considered as a prospective material for bone tissue engineering as a hard tissue implant.

Gentamicin-Loaded Bioactive Hydroxyapatite/Chitosan Composite Coating Electrodeposited on Titanium.

Composite coating of antibiotic gentamicin (Gent), natural polymer chitosan (CS), and hydroxyapatite (HAP) was successfully assessed by applying the electrophoretic deposition (EPD) technique. EPD was performed under optimized deposition conditions (5 V, 12 min) on pure titanium plates, to obtain HAP/CS and HAP/CS/Gent composite coatings in a single step from three-component aqueous suspension, with favorable antibacterial properties. Composite coatings were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray photoelectron analysis, confirming the formation of composite HAP/CS and HAP/CS/Gent coatings on the titanium surface, which is due to intermolecular hydrogen bonds. Employing the XRD technique, HAP was detected by obtaining the characteristic diffraction maximums. Good antibacterial activity of the composite coating loaded with antibiotic (HAP/CS/Gent) was confirmed against Staphylococcus aureus and Escherichia coli, pointing to the high potential for bioapplication. Introduction of gentamicin in HAP/CS/Gent coating caused very mild cytotoxicity in the tested cell lines MRC-5 and L929. MTT testing was used to evaluate cell viability, and HAP/CS was classified as noncytotoxic.

Novel bioactive antimicrobial lignin containing coatings on titanium obtained by electrophoretic deposition.

Hydroxyapatite (HAP) is the most suitable biocompatible material for bone implant coatings; its brittleness, however, is a major obstacle, and the reason why research focuses on creating composites with biopolymers. Organosolv lignin (Lig) is used for the production of composite coatings, and these composites were examined in this study. Titanium substrate is a key biomedical material due to its well-known properties, but infections of the implantation site still impose a serious threat. One approach to prevent infection is to improve antimicrobial properties of the coating material. Silver doped hydroxyapatite (Ag/HAP) and HAP coatings on titanium were obtained by an electrophoretic deposition method in order to control deposited coating mass and morphology by varying applied voltage and deposition time. The effect of lignin on microstructure, morphology and thermal behavior of biocomposite coatings was investigated. The results showed that higher lignin concentrations protect the HAP lattice during sintering, improving coating stability. The corrosion stability was evaluated in simulated body fluid (SBF) at 37 °C. Newly formed plate-shaped carbonate-HAP was detected, indicating enhanced bioactive performance. The antimicrobial efficiency of Ag/HAP/Lig was confirmed by its higher reduction of bacteria Staphylococcus aureus TL (S. aureus TL) than of HAP/Lig coating. Cytotoxicity assay revealed that both coatings can be classified as non-toxic against healthy immunocompetent peripheral blood mononuclear cells (PBMC).

Corrosion stability and bioactivity in simulated body fluid of silver/hydroxyapatite and silver/hydroxyapatite/lignin coatings on titanium obtained by electrophoretic deposition.

Hydroxyapatite is the most suitable biocompatible material for bone implant coatings. However, its brittleness is a major obstacle, and that is why, recently, research focused on creating composites with various biopolymers. In this study, hydroxyapatite coatings were modified with lignin in order to attain corrosion stability and surface porosity that enables osteogenesis. Incorporating silver, well known for its antimicrobial properties, seemed the best strategy for avoiding possible infections. The silver/hydroxyapatite (Ag/HAP) and silver/hydroxyapatite/lignin (Ag/HAP/Lig) coatings were cathaphoretically deposited on titanium from ethanol suspensions, sintered at 900 °C in Ar, and characterized by X-ray diffraction, scanning electron microscopy, field emission scanning electron microscopy, attenuated total reflection Fourier transform infrared, and X-ray photoelectron spectroscopy. The corrosion stability of electrodeposited coatings was evaluated in vitro in Kokubo's simulated body fluid (SBF) at 37 °C using electrochemical impedance spectroscopy. Bioactivity was estimated by immersion in SBF to evaluate the formation of hydroxyapatite on the coating surface. A microcrystalline structure of newly formed plate-shaped carbonate-hydroxyapatite was detected after only 7 days, indicating enhanced bioactive behavior. Both coatings had good corrosion stability during a prolonged immersion time. Among the two, the Ag/HAP/Lig coating had a homogeneous surface, less roughness, and low values of contact angle.

Posterior breast cancer - mammographic and ultrasonographic features.

BACKGROUND/AIM: Posterior breast cancers are located in the prepectoral region of the breast. Owing to this distinctive anatomical localization, physical examination and mammographic or ultrasonographic evaluation can be difficult. The purpose of the study was to assess possibilities of diagnostic mammography and breast ultrasonography in detection and differentiation of posterior breast cancers. METHODS: The study included 40 women with palpable, histopathological confirmed posterior breast cancer. Mammographic and ultrasonographic features were defined according to Breast Imaging Reporting and Data System (BI-RADS) lexicon. RESULTS: Based on standard two-view mammography 87.5%, of the cases were classified as BI-RADS 4 and 5 categories, while after additional mammographic views all the cases were defined as BI-RADS 4 and 5 categories. Among 96 mammographic descriptors, the most frequent were: spiculated mass (24.0%), architectural distortion (16.7%), clustered micro-calcifications (12.6%) and focal asymmetric density (12.6%). The differentiation of the spiculated mass was significantly associated with the possibility to visualize the lesion at two-view mammography (p = 0.009), without the association with lesion diameter (p = 0.083) or histopathological type (p = 0.055). Mammographic signs of invasive lobular carcinoma were significantly different from other histopathological types (architectural distortion, p = 0.003; focal asymmetric density, p = 0.019; association of four or five subtle signs of malignancy, p = 0.006). All cancers were detectable by ultrasonography. Mass lesions were found in 82.0% of the cases. Among 153 ultrasonographic descriptors, the most frequent were: irregular mass (15.7%), lobulated mass (7.2%), abnormal color Doppler signals (20.3%), posterior acoustic attenuation (18.3%). Ultrasonographic BI-RADS 4 and 5 categories were defined in 72.5% of the cases, without a significant difference among various histopathological types (p = 0.109). CONCLUSION: Standard two-view mammography followed by additional mammographic projections is an effective way to demonstrate the spiculated mass and to classify the prepectoral lesion as category BI-RADS 4 or 5. Additional ultrasonography can overcome the mimicry of invasive lobular breast carcinoma at mammography.

Monomeric yeast frataxin is an iron-binding protein.

Friedreich's ataxia, an autosomal cardio- and neurodegenerative disorder that affects 1 in 50,000 humans, is caused by decreased levels of the protein frataxin. Although frataxin is nuclear-encoded, it is targeted to the mitochondrial matrix and necessary for proper regulation of cellular iron homeostasis. Frataxin is required for the cellular production of both heme and iron-sulfur (Fe-S) clusters. Monomeric frataxin binds with high affinity to ferrochelatase, the enzyme involved in iron insertion into porphyrin during heme production. Monomeric frataxin also binds to Isu, the scaffold protein required for assembly of Fe-S cluster intermediates. These processes (heme and Fe-S cluster assembly) share requirements for iron, suggesting that monomeric frataxin might function as the common iron donor. To provide a molecular basis to better understand frataxin's function, we have characterized the binding properties and metal-site structure of ferrous iron bound to monomeric yeast frataxin. Yeast frataxin is stable as an iron-loaded monomer, and the protein can bind two ferrous iron atoms with micromolar binding affinity. Frataxin amino acids affected by the presence of iron are localized within conserved acidic patches located on the surfaces of both helix-1 and strand-1. Under anaerobic conditions, bound metal is stable in the high-spin ferrous state. The metal-ligand coordination geometry of both metal-binding sites is consistent with a six-coordinate iron-(oxygen/nitrogen) based ligand geometry, surely constructed in part from carboxylate and possibly imidazole side chains coming from residues within these conserved acidic patches on the protein. On the basis of our results, we have developed a model for how we believe yeast frataxin interacts with iron.