Neutrophils in Tuberculosis: Cell Biology,Cellular Networking and Multitasking in Host Defense

Neutrophils readily infiltrate infection foci, phagocytose and usually destroy microbes. In tuberculosis (TB), a chronic pulmonary infection caused by Mycobacterium tuberculosis (Mtb), neutrophils harbor bacilli, are abundant in tissue lesions, and their abundances in blood correlate with poor disease outcomes in patients. The biology of these innate immune cells in TB is complex. Neutrophils have been assigned host-beneficial as well as deleterious roles. The short lifespan of neutrophils purified from blood poses challenges to cell biology studies, leaving intracellular biological processes and the precise consequences of Mtb–neutrophil interactions ill-defined. The phenotypic heterogeneity of neutrophils, and their propensity to engage in cellular cross-talk and to exert various functions during homeostasis and disease, have recently been reported, and such observations are newly emerging in TB. Here, we review the interactions of neutrophils with Mtb, including subcellular events and cell fate upon infection, and summarize the cross-talks between neutrophils and lung-residing and -recruited cells. We highlight the roles of neutrophils in TB pathophysiology, discussing recent findings from distinct models of pulmonary TB, and emphasize technical advances that could facilitate the discovery of novel neutrophil-related disease mechanisms and enrich our knowledge of TB pathogenesis.     

Salmonella in eggs: From shopping to consumption—A review providing an evidence-based analysis of risk factors

Nontyphoidal salmonellae are among the most prevalent foodborne pathogens causing gastrointestinal infections worldwide. A high number of cases and outbreaks of salmonellosis are associated with the consumption of eggs and egg products, and several of these occur at the household level. The aim of the current study is to critically evaluate the current status of knowledge on Salmonella in eggs from a consumer's perspective, analyzing the hazard occurrence and the good practices that should be applied to reduce salmonellosis risk. Following a HACCP (Hazard Analysis and Critical Control Point) based approach, some steps along the food journey were identified as Critical Consumer Handling (CCH)—steps in which consumers, through their behavior or choice, can significantly reduce the level of Salmonella in eggs and egg products. From shopping/collecting to consumption, each of these steps is discussed in this review to provide an evidence-based overview of risk factors of human salmonellosis related to egg consumption. The main message to consumers is to choose Salmonella-free eggs (those that some official entity or producer guarantees that does not contain Salmonella), when available, especially for dishes that are not fully heat treated. Second, as guaranteed Salmonella-free eggs are only available in a few countries, refrigerated storage from the point of collection and proper cooking will significantly reduce the risk of salmonellosis. This will require a revision of the actual recommendations/regulations, as not all ensure that eggs are maintained at temperatures that prevent growth of Salmonella from collection until the time of purchasing.     

IgG-Complement Adsorption Behavior Activates Macrophage Mediated Early Immune Responses on Zirconia Implants

Zirconium implants have gained popularity among clinicians due to their superior mechanical properties. However, zirconium implants usually perform less well in early osseointegration than titanium implants. And the degree of severity of the acute inflammation resulting from macrophage activation after implantation determines the result of the implantation. The mechanism by which zirconia implants cause more acute inflammation compared to titanium implants is currently unknown. Here, the complement activation on zirconium oxide is demonstrated, which causes differences in inflammation compared to titanium oxide. More adsorption of immunoglobulin G (IgG) and complement protein C1q together with the more efficient triggering of the complement system is shown to occur on ZrO₂ surfaces. Molecular dynamics (MD) simulations further reveal that IgG exhibits more accessible binding sites on ZrO₂ surfaces due to its hydrophobicity, leading to more efficient complement activation. Reduced inflammation of hydrophilized ZrO₂ compared to non-treated ZrO₂ demonstrates the role of hydrophobicity in the higher inflammation of ZrO₂. The results reveal that complement activation due to conformational changes and greater adsorption of IgG and C1q on ZrO₂ triggers inflammation caused by macrophages, providing new insights for implant design and performance optimization.     

Effect of Fe content on positron annihilation in neutron irradiated V---Fe alloys

Neutron irradiated V---xFe alloys (with x from 0 to 5 at.%) have been studied by the conventional positron annihilation technique. A remarkable narrowing of angular correlation of annihilation radiation (ACAR) curves was observed for all alloys investigated. A specific feature of ACAR curves in pure vanadium is the presence of a narrow component attributed usually to the positronium (Ps) formation in voids, with inner surfaces covered by gaseous impurities such as oxygen. Significant changes in the ACAR curve component intensities with increase of iron content has been observed. At Fe concentration of about 1 at.% the narrow component disappears completely and the intensity of the middle one decreases significantly. It was concluded that the increase of Fe concentration in V---Fe alloys suppresses the void surface contamination by oxygen atoms and changes the positron work function from bulk materials into voids. Such behavior of the ACAR curve component intensities can be explained in terms of radiation-induced segregation of iron atoms at point defect sinks.     

Blood Clots versus PRF: Activating TGF-β Signaling and Inhibiting Inflammation In Vitro

The preparation of platelet-rich fibrin (PRF) requires blood centrifugation to separate the yellow plasma from the red erythrocyte fraction. PRF membranes prepared from coagulated yellow plasma are then transferred to the defect sites to support tissue regeneration. During natural wound healing, however, it is the unfractionated blood clot (UBC) that fills the defect site. It is unclear whether centrifugation is necessary to prepare a blood-derived matrix that supports tissue regeneration. The aim of the present study was to compare lysates prepared from PRF and UBC based on bioassays and degradation of the respective membranes. We report here that lysates prepared from PRF and UBC membranes similarly activate TGF-β signaling, as indicated by the expression of interleukin 11 (IL-11), NADPH oxidase 4 (NOX-4) and proteoglycan 4 (PRG4) in gingival fibroblasts. Consistently, PRF and UBC lysates stimulated the phosphorylation and nuclear translocation of Smad3 in gingival fibroblasts. We further observed that PRF and UBC lysates have comparable anti-inflammatory activity, as shown by the reduction in lipopolysaccharide (LPS)-induced IL-6, inducible nitric oxidase synthase (iNOS) and cyclooxygenase 2 (COX-2) expression in RAW264.7 cells. Moreover, inflammation induced by Poly (1:C) HMW and FSL-1, which are agonists of Toll-like receptor (TLR) 3 and 2/6, respectively, was reduced by both PRF and UBC. PRF and UBC lysates reduced the nuclear translocation of p65 in LPS-induced RAW264.7 cells. In contrast to the similar activity observed in the bioassays, UBC membranes lack the structural integrity of PRF membranes, as indicated by the rapid and spontaneous disintegration of UBC membranes. We show here that the lysates prepared from PRF and UBC possess robust TGF-β and anti-inflammatory activity. However, visual inspection of the PRF and UBC membranes confirmed the negative impact of erythrocytes on the structural integrity of membranes prepared from whole blood. The data from the present study suggest that although both UBC and PRF have potent TGF-β and anti-inflammatory activity, UBC does not have the strength properties required to be used clinically to prepare applicable membranes. Thus, centrifugation is necessary to generate durable and clinically applicable blood-derived membranes.     

Wood-plastic composites based on HDPE and ionic liquid additives

The improvement of wood-plastic composites properties by additives and compatibilizers is a critical issue to produce value-added materials. High-density polyethylene-wood composites have been obtained through compression molding at 140 °C, using two types of additives, namely methyltrioctylammonium bis (trifluoromethylsulfonyl)imide and trihexyltetradecylphosphonium bis (2,4,4-trimethylpentyl) phosphinate room temperature ionic liquids. The ionic liquids improve the interfacial adhesion between the wood and the polymer phases, contributing to an increased stability of the material to water action and to an improved impact resistance and tensile strength in comparison with the reference. Also, the FTIR spectroscopy tests have proven a higher resistance of the ionic liquid-containing composites to accelerated photooxidation. Preliminary screening tests have also proven the antifungal character of the ionic liquids used in this study against brown rot (Postia placenta). This study opens new insights in the domain of polymeric composite materials, through documenting the possibility of blending new types of chemically distinct materials, difficult to be achieved by traditional functionalization/derivatization routes.     

Particle-induced network formation in linear PDMS filled with silica

We study the formation of permanent elastomers from linear PDMS chains by solution blending with up to 25 wt% fumed silica. The physical networks are characterized by time-domain multiple-quantum NMR. Based upon dynamic parameters measured for the linear precursor polymer, we develop a reliable strategy for component separation in this complex heterogeneous system, providing information on the amount of monomers involved in network-like material, in elastically inactive yet entangled linear chains, and isotropically mobile chain ends, as well as on the effective network chain length as measured via the average residual dipolar coupling constant. The use of untreated silica leads to permanent networks, for which the NMR results correlate well with macroscopic determinations of the relaxed Young modulus and the degree of swelling. Surface-modified silicas do not lead to percolated network structures, but still lead to the formation of 20–40% network-like material, with effective network chain lengths that depend on the surface functionalization and thus on the nanoparticle dispersion. Characteristic changes in the mobile chain end fraction with temperature, in particular its decrease with increasing degree of filling are interpreted as a consequence of altered contour-length fluctuations. An aging experiment conducted on a sample prepared by melt blending reveals the microscopic changes in the network structure occurring over many months.     

PALS free volume study of dry and water saturated epoxies

Free volume cavity sizes and fractions of epoxy specimens were determined using positron annihilation lifetime spectroscopy (PALS). PALS data were obtained before and after specimen water equilibration. Specimens were bisphenol A epoxide (B) and/or glycol epoxide (G) cured with a polyamide. Free volume sites increased linearly and cavity sizes decreased linearly with epoxide B:G ratio. Glass transition temperature (T_g) increased with epoxide B:G ratio. Water molecules in wet epoxy B filled approximately six percent of the cavities. Epoxy G cavity size increased 11.4% after water equilibrium and was ascribed to cavity expansion. PALS results differed for commercial corrosion inhibitors in wet and dry mixtures of these epoxides. Zettlemoyer Center for Surface Studies, 7 Asa Dr., Bethlehem, PA 18015. MAHMOUD M. MADANI is with the Zettlemoyer Center for Surface Studies at Lehigh University. He received his B.S. Degree in Physics from Pars College, Tehran, Iran in 1975; his B.S. Honors in 1981, M.S. Degree in 1982, and his Ph.D. Degree in 1986 from Royal Holloway and Bedford New Colleges, University of London. Dr. Madani’s current research studies include the physical chemical characteristics of polymeric coatings and the reliability and characterization of microelectronic packaging materials using PALS, EIS, XPS, SEM, XRD, and MS. He has developed several computer codes for instrumentation interfaces and data analyses. Previously, he was a lecturer in Physics at the University of Bophutatswana, South Africa. Dr. Madani is author and co-author of more than 20 scientific publications. Dr. Madani is a member of the American Physics Society. ROY R. MIRON is a Visiting Research Scientist at the Zettlemoyer Center for Surface Studies at Lehigh University. He received his B.A. and his Ph.D. Degrees from Lehigh University and his M.S. from Middlebury College. Dr. Miron has a broad background in coatings technology. He is the holder of several patents and his publications have appeared inAnalytical Chemistry, Journal Applied Polymer Science, Plastics Paint and Rubber, Plant Engineering, Western Paint Review, and the Hydrocarbon Processing and Petroleum Refiner. He has held memberships in the American Chemical Society and Society of Plastics Engineers. Dr. Miron has presented papers to the Society of Plastics Industry, Society of Plastics Engineers, and the Liberty Bell Corrosion Course. RICHARD D. GRANATA is Lehigh University Senior Research Scientist and Director of the Corrosion Laboratory. He received B.S. and Ph.D. Degrees from The American University in Washington, D.C., studying electrochemistry with Robert Foley. As a Research Scientist at Carnegie-Mellon Institute of Research with Howard Gerhart, he worked on cathodic electrocoating formulations. Moving to Lehigh University, Dr. Granata joined Henry Leidheiser at the Zettlemoyer Center for Surface Studies and continued research in protective polymers and electrochemical corrosion. He has one patent and over 50 technical papers as the author or co-author. His research experience has been acquired in cooperative work on industry and government sponsored programs. He has acquired a broad perspective on corrosion science and technology through this experience with problems involving electrochemical corrosion mechanisms, surface modification by ion implantation, cathodic delamination mechanism, corrosion inhibition, food container life-predictions, corrosion mechanisms in electronics packaging, and protective mechanisms of polymer coatings. Dr. Granata is a member of the Philadelphia Society for Coatings Technology, ECS, National Association of Corrosion Engineers, American Society for Testing and Materials, Steel Structures Paint Council, and American Chemical Society.