86 research outputs found
Meander Line Antenna for LTE Communications
Long Term Evolution (LTE) is a fourth generation standard for wireless communications of high data speed at the user terminal. This evolved technology needs a cutting edge system component to be designed for the node B (Base station) and the user mobile device. In any wireless device, the perform ance of radio communications depends on the design of an efficient antenna. Achieving Long Term Evolution (LTE) frequency bands (the second generation (2G), third generation (3G), and the proposed fourth generation (4G) frequency bands) using a small - size antenna in a compact device remains a major technical challenge. Antenna is an inseparable part of these systems. Meander line antenna is the most usage of antenna that use in design of these applications. The Objective of Paper is to design a meander line antenna for WLAN application that is 2.4 GHz has been achieved. The meander line microstrip antenna has been designed, constructed, and measured. The microstrip element is quarter wavelength at the design frequency. The properties of antenna like return l oss, bandwidth and radiation pattern have been measured. The design starts with calculation of dimension like the width, effective dielectric constant of microstrip line and length of antenna. Thus by using HFSS Version 11 the antenna has been designed and simulated. As the result, the antenna can radiate the signal at WLAN frequency and provide good return loss bandwidth and sufficient gain. The antenna can operate less than - 10db that is 2.4GHz with at s11 measured at - 35.5 db.After finish with the simulat ion, the design has been fabricated on FR4 substrate using the etching technique. Finally the design has been tested with network analyz
LUCIFERASE REPORTER MYCOBACTERIOPHAGES FOR EVALUATING NORBORNENE-BASED ANTITUBERCULOSIS DRUG SUSCEPTIBILITY TESTING ON MYCOBACTERIUM TUBERCULOSIS
ΓΒ ΓΒ Objective: In 2015, 9.6 million people around the world became sick with tuberculosis (TB) disease and 1.5 million TB-related deaths worldwide. Recent increasing incidence of multidrug-resistant (MDR; resistance to at least rifampicin (RIF) and isoniazid [INH]) and extensively drug-resistant (MDR resistance plus resistance to a fluoroquinolone and an aminoglycoside) makes TB a serious concern. Lot of research is needed to deal with this infectious disease for a better alternative in treatment or modification of these older TB drugs. The present study aimed at evaluating antimycobacterial activity of norbornene (NOR) derived INH copolymer with poly ethylene glycol (NOR- polyethylene glycol [PEG]-INH) a novel nanocarrier along with the anti-TB drug using luciferase reporter phages (LRPs).Methods: NOR derived INH accounts for 74% of INH, 24% of NOR, and 2% of PEG. H37Rv control strain, a sensitive, and a resistant strain of Mycobacterium TB (MTB) used in this study. The in vitro activity of the drug was evaluated using absolute concentration method. The resistant strain was evaluated using LRP assay to observe the minimum inhibitory concentration of the drug.Results: Reduction in light units was observed for the resistant strain exposed to plain INH and NOR-PEG-INH separately. 24% of reduction was observed in strains exposed to plain INH whereas 37% of reduction was observed in strains exposed to NOR-PEG-INH.Conclusion: NOR-based INH had better antimycobacterial activity compared to plain INH and RIF. Antimycobacterial activity of INH and RIF increases even with very low dosage with NOR conjugate
Colchicine Does Not Reduce Abdominal Aortic Aneurysm Growth in a Mouse Model
Background and Aims. The nacht domain, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome is upregulated in human abdominal aortic aneurysm (AAA), but its pathogenic role is unclear. The aims of this study were firstly to examine whether the inflammasome was upregulated in a mouse model of AAA and secondly to test whether the inflammasome inhibitor colchicine limited AAA growth. Methods. AAA was induced in eight-week-old male C57BL6/J mice with topical application of elastase to the infrarenal aorta and oral 3-aminopropionitrile (E-BAPN). For aim one, inflammasome activation, abdominal aortic diameter, and rupture were compared between mice with AAA and sham controls. For aim two, 3 weeks after AAA induction, mice were randomly allocated to receive colchicine (n=28, 0.2 mg/kg/d) or vehicle control (n=29). The primary outcome was the rate of maximum aortic diameter increase measured by ultrasound over 13 weeks. Results. There was upregulation of NLRP3 markers interleukin- (IL-) 1 beta (median, IQR; 15.67, 7.11-22.60 pg/mg protein versus 6.87, 4.54-11.60 pg/mg protein, p=.048) and caspase-1 (109, 83-155 relative luminosity units (RLU) versus 45, 38-65 RLU, p <.001) in AAA samples compared to controls. Aortic diameter increase over 80 days (mean difference, MD, 4.3 mm, 95% CI 3.3, 5.3, p <.001) was significantly greater in mice in which aneurysms were induced compared to sham controls. Colchicine did not significantly limit aortic diameter increase over 80 days (MD -0.1 mm, 95% CI -1.1, 0.86, p=.922). Conclusions. The inflammasome was activated in this mouse model of AAA; however, daily oral administration of colchicine did not limit AAA growth
Changes in capsular serotype alter the surface exposure of pneumococcal adhesins and impact virulence
We examined the contribution of serotype on Streptococcus pneumoniae adhesion and virulence during respiratory tract infection using a panel of isogenic TIGR4 (serotype 4) mutants expressing the capsule types 6A (+6A), 7F (+7F) and 23F (+23F) as well as a deleted and restored serotype 4 (+4) control strain. Immunoblots, bacterial capture assays with immobilized antibody, and measurement of mean fluorescent intensity by flow cytometry following incubation of bacteria with antibody, all determined that the surface accessibility, but not total protein levels, of the virulence determinants Pneumococcal surface protein A (PspA), Choline binding protein A (CbpA), and Pneumococcal serine-rich repeat protein (PsrP) changed with serotype. In vitro, bacterial adhesion to Detroit 562 pharyngeal or A549 lung epithelial cells was modestly but significantly altered for +6A, +7F and +23F. In a mouse model of nasopharyngeal colonization, the number of +6A, +7F, and +23F pneumococci in the nasopharynx was reduced 10 to 100-fold versus +4; notably, only mice challenged with +4 developed bacteremia. Intratracheal challenge of mice confirmed that capsule switch strains were highly attenuated for virulence. Compared to +4, the +6A, +7F, and +23F strains were rapidly cleared from the lungs and were not detected in the blood. In mice challenged intraperitoneally, a marked reduction in bacterial blood titers was observed for those challenged with +6A and +7F versus +4 and +23F was undetectable. These findings show that serotype impacts the accessibility of surface adhesins and, in particular, affects virulence within the respiratory tract. They highlight the complex interplay between capsule and protein virulence determinants
Fulminant Lung Fibrosis in Non-Resolvable Covid-19 Requiring Transplantation
BACKGROUND: Coronavirus Disease 2019 (COVID-19) can lead to the development of acute respiratory distress syndrome (ARDS). In some patients with non-resolvable (NR) COVID-19, lung injury can progress rapidly to the point that lung transplantation is the only viable option for survival. This fatal progression of lung injury involves a rapid fibroproliferative response and takes on average 15 weeks from initial symptom presentation. Little is known about the mechanisms that lead to this fulminant lung fibrosis (FLF) in NR-COVID-19.
METHODS: Using a pre-designed unbiased PCR array for fibrotic markers, we analyzed the fibrotic signature in a subset of NR-COVID-19 lungs. We compared the expression profile against control lungs (donor lungs discarded for transplantation), and explanted tissue from patients with idiopathic pulmonary fibrosis (IPF). Subsequently, RT-qPCR, Western blots and immunohistochemistry were conducted to validate and localize selected pro-fibrotic targets. A total of 23 NR-COVID-19 lungs were used for RT-qPCR validation.
FINDINGS: We revealed a unique fibrotic gene signature in NR-COVID-19 that is dominated by a hyper-expression of pro-fibrotic genes, including collagens and periostin. Our results also show a significantly increased expression of Collagen Triple Helix Repeat Containing 1(CTHRC1) which co-localized in areas rich in alpha smooth muscle expression, denoting myofibroblasts. We also show a significant increase in cytokeratin (KRT) 5 and 8 expressing cells adjacent to fibroblastic areas and in areas of apparent epithelial bronchiolization.
INTERPRETATION: Our studies may provide insights into potential cellular mechanisms that lead to a fulminant presentation of lung fibrosis in NR-COVID-19.
FUNDING: National Institute of Health (NIH) Grants R01HL154720, R01DK122796, R01DK109574, R01HL133900, and Department of Defense (DoD) Grant W81XWH2110032 to H.K.E. NIH Grants: R01HL138510 and R01HL157100, DoD Grant W81XWH-19-1-0007, and American Heart Association Grant: 18IPA34170220 to H.K.-Q. American Heart Association: 19CDA34660279, American Lung Association: CA-622265, Parker B. Francis Fellowship, 1UL1TR003167-01 and The Center for Clinical and Translational Sciences, McGovern Medical School to X.Y
Role of cellular senescence and NOX4-mediated oxidative stress in systemic sclerosis pathogenesis.
Systemic sclerosis (SSc) is a systemic autoimmune disease characterized by progressive fibrosis of skin and numerous internal organs and a severe fibroproliferative vasculopathy resulting frequently in severe disability and high mortality. Although the etiology of SSc is unknown and the detailed mechanisms responsible for the fibrotic process have not been fully elucidated, one important observation from a large US population study was the demonstration of a late onset of SSc with a peak incidence between 45 and 54 years of age in African-American females and between 65 and 74 years of age in white females. Although it is not appropriate to consider SSc as a disease of aging, the possibility that senescence changes in the cellular elements involved in its pathogenesis may play a role has not been thoroughly examined. The process of cellular senescence is extremely complex, and the mechanisms, molecular events, and signaling pathways involved have not been fully elucidated; however, there is strong evidence to support the concept that oxidative stress caused by the excessive generation of reactive oxygen species may be one important mechanism involved. On the other hand, numerous studies have implicated oxidative stress in SSc pathogenesis, thus, suggesting a plausible mechanism in which excessive oxidative stress induces cellular senescence and that the molecular events associated with this complex process play an important role in the fibrotic and fibroproliferative vasculopathy characteristic of SSc. Here, recent studies examining the role of cellular senescence and of oxidative stress in SSc pathogenesis will be reviewed
The Pneumococcal Serine-Rich Repeat Protein Is an Intra-Species Bacterial Adhesin That Promotes Bacterial Aggregation In Vivo and in Biofilms
The Pneumococcal serine-rich repeat protein (PsrP) is a pathogenicity island encoded adhesin that has been positively correlated with the ability of Streptococcus pneumoniae to cause invasive disease. Previous studies have shown that PsrP mediates bacterial attachment to Keratin 10 (K10) on the surface of lung cells through amino acids 273β341 located in the Basic Region (BR) domain. In this study we determined that the BR domain of PsrP also mediates an intra-species interaction that promotes the formation of large bacterial aggregates in the nasopharynx and lungs of infected mice as well as in continuous flow-through models of mature biofilms. Using numerous methods, including complementation of mutants with BR domain deficient constructs, fluorescent microscopy with Cy3-labeled recombinant (r)BR, Far Western blotting of bacterial lysates, co-immunoprecipitation with rBR, and growth of biofilms in the presence of antibodies and competitive peptides, we determined that the BR domain, in particular amino acids 122β166 of PsrP, promoted bacterial aggregation and that antibodies against the BR domain were neutralizing. Using similar methodologies, we also determined that SraP and GspB, the Serine-rich repeat proteins (SRRPs) of Staphylococcus aureus and Streptococcus gordonii, respectively, also promoted bacterial aggregation and that their Non-repeat domains bound to their respective SRRPs. This is the first report to show the presence of biofilm-like structures in the lungs of animals infected with S. pneumoniae and show that SRRPs have dual roles as host and bacterial adhesins. These studies suggest that recombinant Non-repeat domains of SRRPs (i.e. BR for S. pneumoniae) may be useful as vaccine antigens to protect against Gram-positive bacteria that cause infection
Streptococcus pneumoniae in Biofilms Are Unable to Cause Invasive Disease Due to Altered Virulence Determinant Production
It is unclear whether Streptococcus pneumoniae in biofilms are virulent and contribute to development of invasive pneumococcal disease (IPD). Using electron microscopy we confirmed the development of mature pneumococcal biofilms in a continuous-flow-through line model and determined that biofilm formation occurred in discrete stages with mature biofilms composed primarily of dead pneumococci. Challenge of mice with equal colony forming units of biofilm and planktonic pneumococci determined that biofilm bacteria were highly attenuated for invasive disease but not nasopharyngeal colonization. Biofilm pneumococci of numerous serotypes were hyper-adhesive and bound to A549 type II pneumocytes and Detroit 562 pharyngeal epithelial cells at levels 2 to 11-fold greater than planktonic counterparts. Using genomic microarrays we examined the pneumococcal transcriptome and determined that during biofilm formation S. pneumoniae down-regulated genes involved in protein synthesis, energy production, metabolism, capsular polysaccharide (CPS) production, and virulence. We confirmed these changes by measuring CPS by ELISA and immunoblotting for the toxin pneumolysin and the bacterial adhesins phosphorylcholine (ChoP), choline-binding protein A (CbpA), and Pneumococcal serine-rich repeat protein (PsrP). We conclude that biofilm pneumococci were avirulent due to reduced CPS and pneumolysin production along with increased ChoP, which is known to bind C-reactive protein and is opsonizing. Likewise, biofilm pneumococci were hyper-adhesive due to selection for the transparent phase variant, reduced CPS, and enhanced production of PsrP, CbpA, and ChoP. These studies suggest that biofilms do not directly contribute to development of IPD and may instead confer a quiescent mode of growth during colonization
miR-199a-5p Is Upregulated during Fibrogenic Response to Tissue Injury and Mediates TGFbeta-Induced Lung Fibroblast Activation by Targeting Caveolin-1
As miRNAs are associated with normal cellular processes, deregulation of miRNAs is thought to play a causative role in many complex diseases. Nevertheless, the precise contribution of miRNAs in fibrotic lung diseases, especially the idiopathic form (IPF), remains poorly understood. Given the poor response rate of IPF patients to current therapy, new insights into the pathogenic mechanisms controlling lung fibroblasts activation, the key cell type driving the fibrogenic process, are essential to develop new therapeutic strategies for this devastating disease. To identify miRNAs with potential roles in lung fibrogenesis, we performed a genome-wide assessment of miRNA expression in lungs from two different mouse strains known for their distinct susceptibility to develop lung fibrosis after bleomycin exposure. This led to the identification of miR-199a-5p as the best miRNA candidate associated with bleomycin response. Importantly, miR-199a-5p pulmonary expression was also significantly increased in IPF patients (94 IPF versus 83 controls). In particular, levels of miR-199a-5p were selectively increased in myofibroblasts from injured mouse lungs and fibroblastic foci, a histologic feature associated with IPF. Therefore, miR-199a-5p profibrotic effects were further investigated in cultured lung fibroblasts: miR-199a-5p expression was induced upon TGFΞ² exposure, and ectopic expression of miR-199a-5p was sufficient to promote the pathogenic activation of pulmonary fibroblasts including proliferation, migration, invasion, and differentiation into myofibroblasts. In addition, we demonstrated that miR-199a-5p is a key effector of TGFΞ² signaling in lung fibroblasts by regulating CAV1, a critical mediator of pulmonary fibrosis. Remarkably, aberrant expression of miR-199a-5p was also found in unilateral ureteral obstruction mouse model of kidney fibrosis, as well as in both bile duct ligation and CCl4-induced mouse models of liver fibrosis, suggesting that dysregulation of miR-199a-5p represents a general mechanism contributing to the fibrotic process. MiR-199a-5p thus behaves as a major regulator of tissue fibrosis with therapeutic potency to treat fibroproliferative diseases. Β© 2013 Lino Cardenas et al
A Variable Region within the Genome of Streptococcus pneumoniae Contributes to Strain-Strain Variation in Virulence
The bacterial factors responsible for the variation in invasive potential between different clones and serotypes of Streptococcus pneumoniae are largely unknown. Therefore, the isolation of rare serotype 1 carriage strains in Indigenous Australian communities provided a unique opportunity to compare the genomes of non-invasive and invasive isolates of the same serotype in order to identify such factors. The human virulence status of non-invasive, intermediately virulent and highly virulent serotype 1 isolates was reflected in mice and showed that whilst both human non-invasive and highly virulent isolates were able to colonize the murine nasopharynx equally, only the human highly virulent isolates were able to invade and survive in the murine lungs and blood. Genomic sequencing comparisons between these isolates identified 8 regions >1 kb in size that were specific to only the highly virulent isolates, and included a version of the pneumococcal pathogenicity island 1 variable region (PPI-1v), phage-associated adherence factors, transporters and metabolic enzymes. In particular, a phage-associated endolysin, a putative iron/lead permease and an operon within PPI-1v exhibited niche-specific changes in expression that suggest important roles for these genes in the lungs and blood. Moreover, in vivo competition between pneumococci carrying PPI-1v derivatives representing the two identified versions of the region showed that the version of PPI-1v in the highly virulent isolates was more competitive than the version from the less virulent isolates in the nasopharyngeal tissue, blood and lungs. This study is the first to perform genomic comparisons between serotype 1 isolates with distinct virulence profiles that correlate between mice and humans, and has highlighted the important role that hypervariable genomic loci, such as PPI-1v, play in pneumococcal disease. The findings of this study have important implications for understanding the processes that drive progression from colonization to invasive disease and will help direct the development of novel therapeutic strategies
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