Asymmetry of the acceleration and deceleration capacity of heart rate is strongly dependent on ventricular premature complexes.

In this letter, we explain the role of acceleration and deceleration capacities as novel risk predictors after myocardial infarction and their relation to the occurrence of ventricular premature complexes.     

Transfer of mRNA Encoding Invariant NKT Cell Receptors Imparts Glycolipid Specific Responses to T Cells and γδT Cells

Cell-based therapies using genetically engineered lymphocytes expressing antigen-specific T cell receptors (TCRs) hold promise for the treatment of several types of cancers. Almost all studies using this modality have focused on transfer of TCR from CD8 cytotoxic T lymphocytes (CTLs). The transfer of TCR from innate lymphocytes to other lymphocytes has not been studied. In the current study, innate and adaptive lymphocytes were transfected with the human NKT cell-derived TCRα and β chain mRNA (the Vα24 and Vβ11 TCR chains). When primary T cells transfected with NKT cell-derived TCR were subsequently stimulated with the NKT ligand, α-galactosylceramide (α-GalCer), they secreted IFN-γ in a ligand-specific manner. Furthermore when γδT cells were transfected with NKT cell-derived TCR mRNA, they demonstrated enhanced proliferation, IFN-γ production and antitumor effects after α-GalCer stimulation as compared to parental γδT cells. Importantly, NKT cell TCR-transfected γδT cells responded to both NKT cell and γδT cell ligands, rendering them bi-potential innate lymphocytes. Because NKT cell receptors are unique and universal invariant receptors in humans, the TCR chains do not yield mispaired receptors with endogenous TCR α and β chains after the transfection. The transfection of NKT cell TCR has the potential to be a new approach to tumor immunotherapy in patients with various types of cancer.     

Beta-Lactamase Producing Escherichia coli Isolates in Imported and Locally Produced Chicken Meat from Ghana

The use of antibiotics in food animals is of public health concern, because resistant zoonotic pathogens can be transmitted to humans. Furthermore, global trade with food may rapidly spread multi-resistant pathogens between countries and even continents. The purpose of the study was to investigate whether imported chicken meat and meat from locally reared chicken are potential sources for human exposure to multi resistant Escherichia coli isolates. 188 samples from imported and locally produced chicken meat were sampled and analyzed. 153 bacteria isolates were successfully cultured and identified as E. coli using MALDI-ToF. Of these 109 isolates were from meat whereas the remaining 44 were isolated from the cloaca of locally reared live chickens. Antimicrobial susceptibility test was done on the identified E. coli isolates. Additionally, beta-lactamases production (ESBL and/or AmpC) were phenotypically confirmed on all isolates showing resistance to cefpodoxime. Beta-lactamase producing (BLP) E. coli meat isolates were further genotyped. Antimicrobial resistance to four antibiotic markers with highest resistance was detected more frequently in isolates from local chickens compared to imported chickens (tetracycline 88.9% vs. 57.5%, sulphonamide 75.0% vs. 46.6%, ampicillin 69.4% vs. 61.6% and trimethoprim 66.7% vs. 38.4%). Beta-lactamase production was found in 29 E. coli meat isolates, with 56.9% of them being multiple drug resistant (≥ 3). The predominant phylogroup identified was B1 followed by A and D, with similar distribution among the isolates from meat of locally reared chickens and imported chickens. Beta-lactamase producing genotype bla _CTX-M-15 (50%; 10/20) was the most frequently drug resistant gene detected. More BLP E. coli isolates were found in imported chicken meat compared to locally reared chickens, demonstrating that these isolates may be spreading through food trade. In conclusion, both imported and locally produced chicken meats are potential sources for human exposure to BLP E. coli.     

Effect of a web-based audit and feedback intervention with outreach visits on the clinical performance of multidisciplinary teams: a cluster-randomized trial in cardiac rehabilitation

Background

The objective of this study was to assess the effect of a web-based audit and feedback (A&F) intervention with outreach visits to support decision-making by multidisciplinary teams.

Methods

We performed a multicentre cluster-randomized trial within the field of comprehensive cardiac rehabilitation (CR) in the Netherlands. Our participants were multidisciplinary teams in Dutch CR centres who were enrolled in the study between July 2012 and December 2013 and received the intervention for at least 1 year. The intervention included web-based A&F with feedback on clinical performance, facilities for goal setting and action planning, and educational outreach visits. Teams were randomized either to receive feedback that was limited to psychosocial rehabilitation (study group A) or to physical rehabilitation (study group B). The main outcome measure was the difference in performance between study groups in 11 care processes and six patient outcomes, measured at patient level. Secondary outcomes included effects on guideline concordance for the four main CR therapies.

Results

Data from 18 centres (14,847 patients) were analysed, of which 12 centres (9353 patients) were assigned to group A and six (5494 patients) to group B. During the intervention, a total of 233 quality improvement goals was identified by participating teams, of which 49 (21%) were achieved during the study period. Except for a modest improvement in data completeness (4.5% improvement per year; 95% CI 0.65 to 8.36), we found no effect of our intervention on any of our primary or secondary outcome measures.

Conclusions

Within a multidisciplinary setting, our web-based A&F intervention engaged teams to define local performance improvement goals but failed to support them in actually completing the improvement actions that were needed to achieve those goals. Future research should focus on improving the actionability of feedback on clinical performance and on addressing the socio-technical perspective of the implementation process.

Trial registration

NTR3251

     

Different positions of males approaching towards females and male choices between webs with and without stabilimentum in a sexually cannibalistic orb‐web spider,Argiope bruennichi

Males of the orb‐weaving spider species Argiope bruennichi (Araneidae) are frequently victims of sexual cannibalism. Therefore, a male spider approaching a female should have strategies to avoid being killed before copulation. Our present field study detected six types of A. bruennichi male positions vis‐à‐vis the female web. In 78% of situations (39/50), only one male attached to a female. Two males attached to the same female in 11 cases. We observed no cases of three or more males on the same female web. We most commonly observed the situation of a male staying in its own web and connecting to a female's web with its silk thread (46% of cases). Of the female webs chosen by males, 68% were decorated with both an upper and lower portion of stabilimentum – a conspicuous white silk structure that reflects much more ultraviolet light than other spider silks in the web. Only 14% (7/50) of the selected webs lacked stabilimentum. Therefore, we conducted an experiment to investigate the males' choice between females' webs with and without stabilimentum. Of the 24 males used in the experiment, 10 chose webs with stabilimentum. This result did not show a strong preference of the male for stabilimentum between equally sized webs, and thus did not support an earlier suggestion that stabilimentum in A. bruennichi might function to guide males to females for mating.     

Crotoxin from Crotalus durissus terrificus Is Able to Down-Modulate the Acute Intestinal Inflammation in Mice

Inflammatory bowel diseases (IBD) is the result of dysregulation of mucosal innate and adaptive immune responses. Factors such as genetic, microbial and environmental are involved in the development of these disorders. Accordingly, animal models that mimic human diseases are tools for the understanding the immunological processes of the IBD as well as to evaluate new therapeutic strategies. Crotoxin (CTX) is the main component of Crotalus durissus terrificus snake venom and has an immunomodulatory effect. Thus, we aimed to evaluate the modulatory effect of CTX in a murine model of colitis induced by 2,4,6- trinitrobenzene sulfonic acid (TNBS). The CTX was administered intraperitoneally 18 hours after the TNBS intrarectal instillation in BALB/c mice. The CTX administration resulted in decreased weight loss, disease activity index (DAI), macroscopic tissue damage, histopathological score and myeloperoxidase (MPO) activity analyzed after 4 days of acute TNBS colitis. Furthermore, the levels of TNF-α, IL-1β and IL-6 were lower in colon tissue homogenates of TNBS-mice that received the CTX when compared with untreated TNBS mice. The analysis of distinct cell populations obtained from the intestinal lamina propria showed that CTX reduced the number of group 3 innate lymphoid cells (ILC3) and Th17 population; CTX decreased IL-17 secretion but did not alter the frequency of CD4⁺Tbet⁺ T cells induced by TNBS instillation in mice. In contrast, increased CD4⁺FoxP3⁺ cell population as well as secretion of TGF-β, prostaglandin E₂ (PGE₂) and lipoxin A₄ (LXA₄) was observed in TNBS-colitis mice treated with CTX compared with untreated TNBS-colitis mice. In conclusion, the CTX is able to modulate the intestinal acute inflammatory response induced by TNBS, resulting in the improvement of clinical status of the mice. This effect of CTX is complex and involves the suppression of the pro-inflammatory environment elicited by intrarectal instillation of TNBS due to the induction of a local anti-inflammatory profile in mice.     

The Impact II,a Very High-Resolution Quadrupole Time-of-Flight Instrument (QTOF) for Deep Shotgun Proteomics

Hybrid quadrupole time-of-flight (QTOF) mass spectrometry is one of the two major principles used in proteomics. Although based on simple fundamentals, it has over the last decades greatly evolved in terms of achievable resolution, mass accuracy, and dynamic range. The Bruker impact platform of QTOF instruments takes advantage of these developments and here we develop and evaluate the impact II for shotgun proteomics applications. Adaption of our heated liquid chromatography system achieved very narrow peptide elution peaks. The impact II is equipped with a new collision cell with both axial and radial ion ejection, more than doubling ion extraction at high tandem MS frequencies. The new reflectron and detector improve resolving power compared with the previous model up to 80%, i.e. to 40,000 at m/z 1222. We analyzed the ion current from the inlet capillary and found very high transmission (>80%) up to the collision cell. Simulation and measurement indicated 60% transfer into the flight tube. We adapted MaxQuant for QTOF data, improving absolute average mass deviations to better than 1.45 ppm. More than 4800 proteins can be identified in a single run of HeLa digest in a 90 min gradient. The workflow achieved high technical reproducibility (R2 > 0.99) and accurate fold change determination in spike-in experiments in complex mixtures. Using label-free quantification we rapidly quantified haploid against diploid yeast and characterized overall proteome differences in mouse cell lines originating from different tissues. Finally, after high pH reversed-phase fractionation we identified 9515 proteins in a triplicate measurement of HeLa peptide mixture and 11,257 proteins in single measurements of cerebellum—the highest proteome coverage reported with a QTOF instrument so far.Building on the fundamental advance of the soft ionization techniques electrospray ionization and matrix-assisted laser desorption/ionization (1, 2), MS-based proteomics has advanced tremendously over the last two decades (3–6). Bottom-up, shotgun proteomics is usually performed in a liquid chromatography-tandem MS (LC-MS/MS)¹ format, where nanoscale liquid chromatography is coupled through electrospray ionization to an instrument capable of measuring a mass spectrum and fragmenting the recognized precursor peaks on the chromatographic time scale. Fundamental challenges of shotgun proteomics include the very large numbers of peptides that elute over relatively short periods and peptide abundances that vary by many orders of magnitude. Developments in mass spectrometers toward higher sensitivity, sequencing speed, and resolution were needed and helped to address these critical challenges (7, 8). Especially the introduction of the Orbitrap mass analyzers has advanced the state of the art of the field because of their very high resolution and mass accuracy (9, 10). A popular configuration couples a quadrupole mass filter for precursor selection to the Orbitrap analyzer in a compact benchtop format (11–13).In addition to the improvements in MS instrumentation, there have been key advances in the entire proteomics workflow, from sample preparation through improved LC systems and in computational proteomics (14–16). Together, such advances are making shotgun proteomics increasingly comprehensive and deep analyses can now be performed in a reasonable time (13, 17–19). Nevertheless, complete analysis of all expressed proteins in a complex system remains extremely challenging and complete measurement of all the peptides produced in shotgun proteomics may not even be possible in principle (20, 21). Therefore, an urgent need for continued improvements in proteomics technology remains.Besides the Orbitrap analyzer and other ion trap technologies, the main alternative MS technology is time-of-flight, a technology that has been used for many decades in diverse fields. The configuration employed in proteomics laboratories combines a quadrupole mass filter via a collision cell and orthogonal acceleration unit to a reflectron and a multichannel plate (MCP) detector (22). TOF scans are generated in much less than a millisecond (ms), and a number of these “pulses” are added to obtain an MS or MS/MS spectrum with the desired signal to noise ratio. Our own laboratory has used such a quadrupole time-of-flight (QTOF) instrument as the main workhorse in proteomics for many years, but then switched to high-resolution trapping instruments because of their superior resolution and mass accuracy. However, TOF technology has fundamental attractions, such as the extremely high scan speed and the absence of space charge, which limits the number of usable ions in all trapping instruments. In principle, the high spectra rate makes TOF instruments capable of making use of the majority of ions, thus promising optimal sensitivity, dynamic range and hence quantification. It also means that TOF can naturally be interfaced with ion mobility devices, which typically separate ions on the ms time scale. Data independent analysis strategies such as MS^E, in which all precursors are fragmented simultaneously (23, 24) or SWATH, in which the precursor ion window is rapidly cycled through the entire mass range (25), also make use of the high scanning speed offered by QTOF instruments. It appears that QTOFs are set to make a comeback in proteomics with recent examples showing impressive depth of coverage of complex proteomes. For instance, using a variant of the MS^E method, identification of 5468 proteins was reported in HeLa cells in single shots and small sample amounts (26). In another report, employing ion mobility for better transmission of fragment ions to the detector led to the identification of up to 7548 proteins in human ovary tissue (27).In this paper, we describe the impact II™, a benchtop QTOF instrument from Bruker Daltonics, and its use in shotgun proteomics. This QTOF instrument is a member of an instrument family first introduced in 2008, which consists of the compact, the impact, and the maXis. The original impact was introduced in 2011 and was followed by the impact HD, which was equipped with a better digitizer, expanding the dynamic range of the detector. With the impact II, which became commercially available in 2014, we aimed to achieve a resolution and sequencing speed adequate for demanding shotgun proteomics experiments. To achieve this we developed an improved collision cell, orthogonal accelerator scheme, reflectron, and detector. Here we measure ion transmission characteristics of this instrument and the actually realized resolution and mass accuracy in typical proteomics experiments. Furthermore, we investigated the attainable proteome coverage in single shot analysis and we ask if QTOF performance is now sufficient for very deep characterization of complex cell line and tissue proteomes.