357 research outputs found
Viscoelastic properties of human and bovine articular cartilage : a comparison of frequency-dependent trends
Acknowledgments The authors would like to thank Spencer C. Barnes and Hamid Sadeghi for assistance during experimentation. We would also like to thank patients donating tissue and the surgeons collecting these. Funding The equipment used in this study was funded by Arthritis Research UK (Grant number H0671). We are grateful to Arthritis Research UK for the award of a PhD studentship to Anna A. Cederlund (Grant number 19971). Arthritis Research UK had no role in the design of the study and collection, analysis and interpretation of data and in writing the manuscript.Peer reviewedPublisher PD
Antimicrobial Nodule-Specific Cysteine-Rich Peptides Induce Membrane Depolarization-Associated Changes in the Transcriptome of Sinorhizobium meliloti.
Leguminous plants establish symbiosis with nitrogen-fixing alpha- and betaproteobacteria, collectively called rhizobia, which provide combined nitrogen to support plant growth. Members of the inverted repeat-lacking clade of legumes impose terminal differentiation on their endosymbiotic bacterium partners with the help of the nodule-specific cysteine-rich (NCR) peptide family composed of close to 600 members. Among the few tested NCR peptides, cationic ones had antirhizobial activity measured by reduction or elimination of the CFU and uptake of the membrane-impermeable dye propidium iodide. Here, the antimicrobial spectrum of two of these peptides, NCR247 and NCR335, was investigated, and their effect on the transcriptome of the natural target Sinorhizobium meliloti was characterized. Both peptides were able to kill quickly a wide range of Gram-negative and Gram-positive bacteria; however, their spectra were only partially overlapping, and differences were found also in their efficacy on given strains, indicating that the actions of NCR247 and NCR335 might be similar though not identical. Treatment of S. meliloti cultures with either peptide resulted in a quick downregulation of genes involved in basic cellular functions, such as transcription-translation and energy production, as well as upregulation of genes involved in stress and oxidative stress responses and membrane transport. Similar changes provoked mainly in Gram-positive bacteria by antimicrobial agents were coupled with the destruction of membrane potential, indicating that it might also be a common step in the bactericidal actions of NCR247 and NCR335
Cellular responses of Candida albicans to phagocytosis and the extracellular activities of neutrophils are critical to counteract carbohydrate starvation, oxidative and nitrosative stress
Acknowledgments We thank Alexander Johnson (yhb1D/D), Karl Kuchler (sodD/D mutants), Janet Quinn (hog1D/D, hog1/cap1D/D, trx1D/D) and Peter Staib (ssu1D/D) for providing mutant strains. We acknowledge helpful discussions with our colleagues from the Microbial Pathogenicity Mechanisms Department, Fungal Septomics and the Microbial Biochemistry and Physiology Research Group at the Hans Kno¨ll Institute (HKI), specially Ilse D. Jacobsen, Duncan Wilson, Sascha Brunke, Lydia Kasper, Franziska Gerwien, Sea´na Duggan, Katrin Haupt, Kerstin Hu¨nniger, and Matthias Brock, as well as from our partners in the FINSysB Network. Author Contributions Conceived and designed the experiments: PM HW IMB AJPB OK BH. Performed the experiments: PM CD HW. Analyzed the data: PM HW IMB AJPB OK BH. Wrote the paper: PM HW OK AJPB BH.Peer reviewedPublisher PD
MRI of the lung (3/3)-current applications and future perspectives
BACKGROUND: MRI of the lung is recommended in a number of clinical indications. Having a non-radiation alternative is particularly attractive in children and young subjects, or pregnant women. METHODS: Provided there is sufficient expertise, magnetic resonance imaging (MRI) may be considered as the preferential modality in specific clinical conditions such as cystic fibrosis and acute pulmonary embolism, since additional functional information on respiratory mechanics and regional lung perfusion is provided. In other cases, such as tumours and pneumonia in children, lung MRI may be considered an alternative or adjunct to other modalities with at least similar diagnostic value. RESULTS: In interstitial lung disease, the clinical utility of MRI remains to be proven, but it could provide additional information that will be beneficial in research, or at some stage in clinical practice. Customised protocols for chest imaging combine fast breath-hold acquisitions from a "buffet" of sequences. Having introduced details of imaging protocols in previous articles, the aim of this manuscript is to discuss the advantages and limitations of lung MRI in current clinical practice. CONCLUSION: New developments and future perspectives such as motion-compensated imaging with self-navigated sequences or fast Fourier decomposition MRI for non-contrast enhanced ventilation- and perfusion-weighted imaging of the lung are discussed. Main Messages • MRI evolves as a third lung imaging modality, combining morphological and functional information. • It may be considered first choice in cystic fibrosis and pulmonary embolism of young and pregnant patients. • In other cases (tumours, pneumonia in children), it is an alternative or adjunct to X-ray and CT. • In interstitial lung disease, it serves for research, but the clinical value remains to be proven. • New users are advised to make themselves familiar with the particular advantages and limitations
AvBD1 nucleotide polymorphisms, peptide antimicrobial activities and microbial colonisation of the broiler chicken gut
Abstract Background The importance of poultry as a global source of protein underpins the chicken genome and associated SNP data as key tools in selecting and breeding healthy robust birds with improved disease resistance. SNPs affecting host peptides involved in the innate defences tend to be rare, but three non-synonymous SNPs in the avian β-defensin (AvBD1) gene encoding the variant peptides NYH, SSY and NYY were identified that segregated specifically to three lines of commercial broiler chickens Line X (LX), Line Y(LY) and Line Z. The impacts of such amino acid changes on peptide antimicrobial properties were analysed in vitro and described in relation to the caecal microbiota and gut health of LX and LY birds. Results Time-kill and radial immune diffusion assays indicated all three peptides to have antimicrobial properties against gram negative and positive bacteria with a hierarchy of NYH > SSY > NYY. Calcein leakage assays supported AvBD1 NYH as the most potent membrane permeabilising agent although no significant differences in secondary structure were identified to explain this. However, distinct claw regions, identified by 3D modelling and proposed to play a key role in microbial membrane attachment, and permeation, were more distinct in the NYH model. In vivo AvBD1 synthesis was detected in the bird gut epithelia. Analyses of the caecal gut microbiota of young day 4 birds suggested trends in Lactobacilli sp. colonisation at days 4 (9% LX vs × 30% LY) and 28 (20% LX vs 12% LY) respectively, but these were not statistically significant (P > 0.05). Conclusion Amino acid changes altering the killing capacity of the AvBD1 peptide were associated with two different bird lines, but such changes did not impact significantly on caecal gut microbiota
Overcoming biochar limitations to remediate pentachlorophenol in soil by modifying its electrochemical properties
In this study, we produced modified biochars with enhanced electrochemical properties to increase PCP remediation in soil. Although all biochars enhanced PCP remediation in aerobic conditions, only a few did in anaerobic soil. The most successful modifications were (i) the preloading of biomass with 10% w/w FeCl3, to obtain a biochar rich in redox-active metals (B-Fe); (ii) the oxidation of a conductive biochar pyrolyzed at 1000 ºC with 0.025 M KMnO4, to produce a biochar with both moderate conductivity and redox capacity (B-1000-KMnO4); and (iii) KMnO4 oxidation of an amorphous biochar pyrolyzed at 400 ºC to obtain a biochar with very high redox capacity (B-KMnO4). B-Fe reduced extractable PCP to almost zero after 50 days in both incubations, but showed slow kinetics of remediation in aerobic soil. B-1000-KMnO4 had the highest rate of remediation under aerobic conditions, but no significant effect under anaerobic conditions. B-KMnO4, however, presented high rates of remediation and high removal of extractable PCP under both conditions, which made it the recommended modification strategy for increased PCP remediation. We found that the degree of remediation primarily depends on the redox capacity, while the rate of remediation was determined by both the conductivity and redox capacity of biochar
Short-Term Effects of Biogas Digestates and Pig Slurry Application on Soil Microbial Activity
The effect of four biogas digestates (BD-A, BD-B, BD-C, and BD-D) and pig slurry (PS) on soil microbial functions was assessed at application rates corresponding to 0–1120 kg NH4+-N ha−1. At dose corresponding to 140 kg NH4+-N ha−1, 30.9–32.5% of the carbon applied in BD-A, BD-C, and PS was utilized during 12 days, while for BD-B and BD-D corresponding utilization was 19.0 and 16.9%, respectively. All BDs resulted in net nitrogen assimilation at low rates (17.5–140 kg NH4+-N ha−1) but net mineralization dominated at higher rates. PS resulted in net mineralization at all application rates. All residues inhibited potential ammonium oxidation (PAO), with EC50-values ranging between 45 and 302 kg NH4+-N ha−1. Low rates of BDs appeared to weakly stimulate potential denitrification activity (PDA), while higher rates resulted in logarithmic decrease. The EC50-values for PDA were between 238 and 347 kg NH4+-N ha−1. No inhibition of PDA was observed after amendment with PS. In conclusion, biogas digestates inhibited ammonia oxidation and denitrification, which could be an early warning of potential hazardous substances in the digestates. However, this effect can also be regarded as positive, since it may reduce nitrogen losses
Narcolepsy patients have antibodies that stain distinct cell populations in rat brain and influence sleep patterns.
Narcolepsy is a chronic sleep disorder, likely with an autoimmune component. During 2009 and 2010, a link between A(H1N1)pdm09 Pandemrix vaccination and onset of narcolepsy was suggested in Scandinavia. In this study, we searched for autoantibodies related to narcolepsy using a neuroanatomical array: rat brain sections were processed for immunohistochemistry/double labeling using patient sera/cerebrospinal fluid as primary antibodies. Sera from 89 narcoleptic patients, 52 patients with other sleep-related disorders (OSRDs), and 137 healthy controls were examined. Three distinct patterns of immunoreactivity were of particular interest: pattern A, hypothalamic melanin-concentrating hormone and proopiomelanocortin but not hypocretin/orexin neurons; pattern B, GABAergic cortical interneurons; and pattern C, mainly globus pallidus neurons. Altogether, 24 of 89 (27%) narcoleptics exhibited pattern A or B or C. None of the patterns were exclusive for narcolepsy but were also detected in the OSRD group at significantly lower numbers. Also, some healthy controls exhibited these patterns. The antigen of pattern A autoantibodies was identified as the common C-terminal epitope of neuropeptide glutamic acid-isoleucine/alpha-melanocyte-stimulating hormone (NEI/alphaMSH) peptides. Passive transfer experiments on rat showed significant effects of pattern A human IgGs on rapid eye movement and slow-wave sleep time parameters in the inactive phase and EEG theta-power in the active phase. We suggest that NEI/alphaMSH autoantibodies may interfere with the fine regulation of sleep, contributing to the complex pathogenesis of narcolepsy and OSRDs. Also, patterns B and C are potentially interesting, because recent data suggest a relevance of those brain regions/neuron populations in the regulation of sleep/arousal
Linguistic validation and cultural adaptation of an English version of the Evaluation of Daily Activity Questionnaire in rheumatoid arthritis
Background: To linguistically validate and culturally adapt the Evaluation of Daily Activity Questionnaire (EDAQ) for use in rheumatoid arthritis (RA) from Swedish to British English. The EDAQ is a patient reported outcome measure of daily activity ability. It includes 11 activity domains (Eating and Drinking; Personal Care; Dressing; Bathing; Cooking; Moving Indoors; House Cleaning; Laundry; Moving and Transfers; Communication; Moving Outdoors) and was developed for use in rheumatoid arthritis (RA).
Methods: The EDAQ was translated from Swedish to English using standard methods. Activity diaries, cognitive debriefing interviews and focus groups were completed with people with RA to: generate new culturally applicable items; identify important items in the Swedish version to retain in the English version; and develop the English EDAQ based on their views of content and layout. Content validity was established by linking the EDAQ to the International Classification of Functioning RA Core Set.
Results: The English EDAQ translation was harmonised with the Swedish version to ensure equivalence of meaning. Sixty-one people with RA participated. 156 activities were identified from 31 activity diaries and included in a draft English EDAQ. Following interviews (n=20) and four focus groups, 138 activities were retained and three additional domains added (Gardening/Household Maintenance; Caring; and Leisure/ Social Activities). Most ICF RA Core Set activities are in the EDAQ.
Conclusions: The English EDAQ is a detailed self-report measure of ability in RA. with good content validity
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