Neutrophils release DNA-based extracellular traps to capture and kill bacteria. The mechanism(s) and proteins that promote neutrophil extracellular trap (NET)-mediated bacterial trapping are not ...clearly established. Surfactant protein D (SP-D) is an innate immune collectin present in many mucosal surfaces. We hypothesized that SP-D can bind both the pathogens and NETs to augment NET-mediated bacterial trapping. To test this hypothesis, we used LPS and Pseudomonas aeruginosa pneumonia mouse models and performed in vivo and ex vivo assays. In this study, we show that NETs are produced by the neutrophils recruited to the airways in response to the bacterial ligand. Notably, NETs are detected as short fragments of DNA-protein complexes in the airways as opposed to the long stringlike structures seen in ex vivo cultures. SP-D recognizes both the short NET fragments and the long NET DNA structures. SP-D-NET copurification studies further show that SP-D can simultaneously recognize NETs and carbohydrate ligands in vivo. Similar to the LPS model, soluble DNA-protein complexes and increased amounts of SP-D are detected in the murine model of P. aeruginosa pneumonia. We then tested the effect of SP-D on NET-mediated trapping of P. aeruginosa by means of Western blots, fluorescence microscopy, and scanning electron microscopy. Results of these experiments show that SP-D microagglutinates P. aeruginosa and allows an efficient bacterial trapping by NETs. Collectively, these findings provide a unique biological relevance for SP-D-DNA interactions and places SP-D as an important innate immune protein that promotes bacterial trapping by NETs during neutrophil-mediated host defense.
Nonhydrolysable stable analogues of τ‐phosphohistidine (τ‐pHis) and π‐pHis have been designed, aided by electrostatic surface potential calculations, and subsequently synthesized. The τ‐pHis and ...π‐pHis analogues (phosphopyrazole 8 and pyridyl amino amide 13, respectively) were used as haptens to generate pHis polyclonal antibodies. Both τ‐pHis and π‐pHis conjugates in the form of BSA‐glutaraldehyde‐τ‐pHis and BSA‐glutaraldehyde‐π‐pHis were synthesized and characterized by 31P NMR spectroscopy. Commercially available τ‐pHis (SC56‐2) and π‐pHis (SC1‐1; SC50‐3) monoclonal antibodies were used to show that the BSA−G‐τ‐pHis and BSA−G‐π‐pHis conjugates could be used to assess the selectivity of pHis antibodies in a competitive ELISA. Subsequently, the selectivity of the pHis antibodies generated by using phosphopyrazole 8 and pyridyl amino amide 13 as haptens was assessed by competitive ELISA against His, pSer, pThr, pTyr, τ‐pHis and π‐pHis. Antibodies generated by using phosphopyrazole 8 as a hapten were found to be selective for τ‐pHis, and antibodies generated by using pyridyl amino amide 13 were found to be selective for π‐pHis. Both τ‐ and π‐pHis antibodies were shown to be effective in immunological experiments, including ELISA, western blot, and immunofluorescence. The τ‐pHis antibody was also shown to be useful in the immunoprecipitation of proteins containing pHis.
Histidine phosphorylation is a post translation modification that occurs in all cells and is currently understudied. Using DFT calculations, we report the synthesis of a pyrazole τ‐pHis and a pyridine π‐pHis analogue. The pyrazole and pyridine analogues were used to generate isomer‐selective τ‐pHis and π‐pHis antibodies, respectively. The antibodies were applicable in many immunological techniques.
Polyclonal antibodies raised against 4-phosphothiophen-2-yl alanine 2a, a novel five-membered ring analogue of phosphotyrosine, showed high selectivity for phosphotyrosine and no cross-reactivity ...with other phosphorylated amino acids. Western blots showed that the polyclonal was similarly effective, but different in selectivity, to a commercially available monoclonal antibody.
This article offers a revisionary re-description of the central characteristics of terrorism in an attempt to put forward a persuasive definition under which scholars could converge. It accepts that ...there are valid reasons for rejecting the term, not least because it is a socially constructed label that has been misused in public discourse. Nonetheless, it argues that, based on a 'minimal foundationalist' ontological position, it is possible to define and describe the key characteristics of terrorist violence. The article then attempts to re-describe the characteristics of terrorism by dealing with a number of common misconceptions, such as the notion that terrorism is violence directed at civilians or non-combatants by non-state actors, before offering a contingent definition of terrorism relevant to the present historical moment. The article concludes by outlining a range of additional pragmatic and normative reasons for retaining the term as a research concept.
We examine whether requiring (IFRS) versus allowing (UK GAAP) conditional capitalisation of development expenditure affects the extent to which capitalisation conveys more information about future ...earnings, relative to expensing. We show that capitalisation results in current returns incorporating more future earnings information than expensing under UK GAAP but not under IFRS. i.e., the amount of information incorporated into market prices of capitalisers is the same as that from firms expensing R&D under IFRS. This result holds irrespective of a firm’s earnings management incentives or strength of corporate governance for the period under IFRS. We argue that this is because investors experience greater uncertainty regarding the realisation of future economic benefits associated with the development costs capitalised in the post-IFRS period. Consistent with this, we do find a positive association between capitalised R&D and future earnings variability in the post-IFRS period only, as well as short-term positive abnormal returns for capitalisers relative to expensers in the pre-IFRS period only. Overall, these findings suggest that when moving away from a standard that offers an overt option to capitalise or expense, capitalisation comes with greater uncertainty, which is resolved only in the long term.
Theoretically-driven, market-based contingent claims models have recently been applied to the field of corporate insolvency prediction in an attempt to provide the art with a theoretical methodology ...that has been lacking in the past. Limited studies have been carried out in order directly to compare the performance of these models with that of their accounting number-based counterparts. We use receiver operating characteristic curves to assess the efficacy of thirteen selected models using, for the first time, post-IFRS UK data; and investigate the distributional properties of model efficacy. We find that the efficacy of the models is generally less than that reported in the prior literature; but that the contingent claims models outperform models which use accounting numbers. We also obtain the counter-intuitive finding that predictions based on a single variable can be as efficient as those which are based on models which are far more complicated – in terms of variable variety and mathematical construction. Finally, we develop and test a naïve version of the down-and-out-call barrier option model for insolvency prediction and find that, despite its simple formulation, it performs favourably compared alongside other contingent claims models.
There is growing evidence to suggest that phosphohistidines are present at significant levels in mammalian cells and play a part in regulating cellular activity, in particular signaling pathways ...related to cancer. Because of the chemical instability of phosphohistidine at neutral or acid pH, it remains unclear how much phosphohistidine is present in cells. Here we describe a protocol for extracting proteins from mammalian cells in a way that avoids loss of covalent phosphates from proteins, and use it to measure phosphohistidine concentrations in human bronchial epithelial cell (16HBE14o-) lysate using
31
P NMR spectroscopic analysis. Phosphohistidine is determined on average to be approximately one third as abundant as phosphoserine and phosphothreonine combined (and thus roughly 15 times more abundant than phosphotyrosine). The amount of phosphohistidine, and phosphoserine/phosphothreonine per gram of protein from a cell lysate was determined to be 23 μmol/g and 68 μmol/g respectively. The amount of phosphohistidine, and phosphoserine/phosphothreonine per cell was determined to be 1.8 fmol/cell, and 5.8 fmol/cell respectively. Phosphorylation is largely at the N3 (
tele
) position. Typical tryptic digest conditions result in loss of most of the phosphohistidine present, which may explain why the amounts reported here are greater than is generally seen using mass spectroscopy assays. The results further strengthen the case for a functional role of phosphohistidine in eukaryotic cells.
Abdominal aortic aneurysms (AAAs) with adverse morphology of the aneurysm neck are “complex”. Techniques employed to repair complex aneurysms include open surgical repair (OSR) and a number of on ...label endovascular techniques such as fenestrated endovascular aneurysm repair (FEVAR) and endovascular aneurysm repair (EVAR) with adjuncts (including chimneys and endo-anchors), as well as off label use of standard EVAR. The aim was to conduct a network meta-analysis (NMA) of published comparative outcomes.
An electronic search was performed in Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials (CENTRAL). These databases were interrogated using the PubMed interface and the Healthcare Databases Advanced Search (HDAS) interface developed by the National Institute of Health and Care Excellence.
Online databases were interrogated up to April 2020. Studies were included if they compared outcomes between at least two methods of repair for complex aneurysms (those with at least one adverse neck feature: absent/short neck, conicality, angulation, calcification, large diameter, and thrombus). The primary outcome measure was peri-operative death. Pre-registration was done in PROSPERO (CRD42020177482).
The search identified 24 observational studies and 7854 patients who underwent OSR, FEVAR, off label EVAR, or chimney EVAR. No comparative studies included EVAR with endo-anchors. NMA was performed on 23 studies that reported outcomes of aneurysms with short/absent infrarenal neck. Compared with OSR, off label EVAR (relative risk RR 0.10, 95% confidence interval CI 0.01 – 0.41) and FEVAR (RR 0.62, 95% CI 0.32–0.94) were associated with lower peri-operative mortality. This difference was not seen at the midterm follow up (30 months). Compared with OSR, FEVAR was associated with a lower peri-operative myocardial infarction (MI) rate (RR 0.37, 95% CI 0.16 – 0.62) but a higher midterm re-intervention rate (hazard ratio 1.65, 95% CI 1.04 – 2.66). All studies had a “moderate” or “high” risk of bias. Confidence in the network findings (GRADE) was generally “low”.
This NMA demonstrated a peri-operative survival benefit for off label EVAR and FEVAR compared with OSR, potentially due to reduced risk of MI. FEVAR carries a greater midterm re-intervention risk than OSR, with potential implications for cost effectiveness. There is paucity of comparative data for cases with adverse neck features other than short length.
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