77 research outputs found

    Insects Inhabiting the Burrows of the Ozark Pocket Gopher in Arkansas

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    Pocket gopher burrows provide a stable environment for a variety of inquilines; hence this mammal is regarded as a keystone species. Most of the arthropods inhabiting pocket gopher burrows are restricted to this microhabitat. As part of a planned state-wide biotic survey of insects inhabiting this unusual microhabitat, we have focused our initial sampling efforts on the Ozark pocket gopher (Geomys bursarius ozarkensis; Geomyidae). In 2004 and 2005, pitfall traps were established in pocket gopher burrows and in 2007 and 2008, nests and associated chambers were excavated. Retrieved samples contained scarab, histerid, and rove beetles, cave crickets and anthomyiid flies. The histerids consisted of five species, one of which is undescribed, and all of which are new state records. A total of five species of scarab beetles were collected and all of these represent new state records. Two species of cave crickets were collected; one appears to be undescribed, and the other is essentially a Great Plains species and represents a considerable range extension. Both crickets are new to Arkansas

    Dynamics of the Gut Microbiota in Children Receiving Selective or Total Gut Decontamination Treatment during Hematopoietic Stem Cell Transplantation

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    Bloodstream infections and graft-versus-host disease are common complications after hematopoietic stem cell transplantation (HSCT) procedures, associated with the gut microbiota that acts as a reservoir for opportunistic pathogens. Selective gut decontamination (SGD) and total gut decontamination (TGD) during HSCT have been associated with a decreased risk of developing these complications after transplantation. However, because studies have shown conflicting results, the use of these treatments remains subject of debate. In addition, their impact on the gut microbiota is not well studied. The aim of this study was to elucidate the dynamics of the microbiota during and after TGD and to compare these with the dynamics of SGD. In this prospective, observational, single center study fecal samples were longitudinally collected from 19 children eligible for allogenic HSCT (TGD, n=12; SGD, n=7), weekly during hospital admission and monthly after discharge. In addition, fecal samples were collected from 3 family stem cell donors. Fecal microbiota structure of patients and donors was determined by 16S rRNA gene amplicon sequencing. Microbiota richness and diversity markedly decreased during SGD and TGD and gradually increased after cessation of decontamination treatment. During SGD, gut microbiota composition was relatively stable and dominated by Bacteroides, whereas it showed high inter- and intraindividual variation and low Bacteroides abundance during TGD. In some children TGD allowed the genera Enterococcus and Streptococcus to thrive during treatment. A gut microbiota dominated by Bacteroides was associated with increased predicted activity of several metabolic processes. Comparing the microbiota of recipients and their donors indicated that receiving an SCT did not alter the patient's microbiota to become more similar to that of its donor. Overall, our findings indicate that SGD and TGD affect gut microbiota structure in a treatment-specific manner. Whether these treatments affect clinical outcomes via interference with the gut microbiota needs to be further elucidated. (C) 2019 American Society for Blood and Marrow Transplantation.Peer reviewe

    The effectiveness of neuromuscular warm-up strategies, that require no additional equipment, for preventing lower limb injuries during sports participation: a systematic review

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    PMCID: PMC3408383The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1741-7015/10/75. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

    PReVENT - protective ventilation in patients without ARDS at start of ventilation: study protocol for a randomized controlled trial

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    Background It is uncertain whether lung-protective mechanical ventilation using low tidal volumes should be used in all critically ill patients, irrespective of the presence of the acute respiratory distress syndrome (ARDS). A low tidal volume strategy includes use of higher respiratory rates, which could be associated with increased sedation needs, a higher incidence of delirium, and an increased risk of patient-ventilator asynchrony and ICU-acquired weakness. Another alleged side-effect of low tidal volume ventilation is the risk of atelectasis. All of these could offset the beneficial effects of low tidal volume ventilation as found in patients with ARDS. Methods/Design PReVENT is a national multicenter randomized controlled trial in invasively ventilated ICU patients without ARDS with an anticipated duration of ventilation of longer than 24 hours in 5 ICUs in The Netherlands. Consecutive patients are randomly assigned to a low tidal volume strategy using tidal volumes from 4 to 6 ml/kg predicted body weight (PBW) or a high tidal volume ventilation strategy using tidal volumes from 8 to 10 ml/kg PBW. The primary endpoint is the number of ventilator-free days and alive at day 28. Secondary endpoints include ICU and hospital length of stay (LOS), ICU and hospital mortality, the incidence of pulmonary complications, including ARDS, pneumonia, atelectasis, and pneumothorax, the cumulative use and duration of sedatives and neuromuscular blocking agents, incidence of ICU delirium, and the need for decreasing of instrumental dead space. Discussion PReVENT is the first randomized controlled trial comparing a low tidal volume strategy with a high tidal volume strategy, in patients without ARDS at onset of ventilation, that recruits a sufficient number of patients to test the hypothesis that a low tidal volume strategy benefits patients without ARDS with regard to a clinically relevant endpoin

    Anti-HLA antibodies with complementary and synergistic interaction geometries promote classical complement activation on platelets

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    High titers of HLA antibodies are associated with platelet refractoriness, causing poor platelet increments after transfusions in a subset of patients with HLA antibodies. Currently, we do not know the biological mechanisms that explain the variability in clinical responses in HLA alloimmunized patients receiving platelet transfusions. Previously we showed that a subset of anti-HLA IgG-antibodies induces FcγRIIa-dependent platelet activation and enhanced phagocytosis. Here, we investigated whether anti-HLA IgG can induce complement activation on platelets. We found that a subset of anti-HLA IgG induced complement activation via the classical pathway, causing C4b and C3b deposition and formation of the membrane-attack complex. This resulted in permeabilization of platelet membranes and increased calcium influx. Complement activation also caused enhanced α-granule release, as measured by CD62P surface exposure. Blocking studies revealed that platelet activation was caused by FcγRIIa-dependent signaling as well as HLA antibody induced complement activation. Synergistic complement activation employing combinations of monoclonal IgGs suggested that assembly of oligomeric IgG complexes strongly promoted complement activation through binding of IgGs to different antigenic determinants on HLA. In agreement with this, we observed that preventing anti-HLA-IgG hexamer formation using an IgG-Fc:Fc blocking peptide, completely inhibited C3b and C4b deposition. Our results show that HLA antibodies can induce complement activation on platelets including membrane attack complex formation, pore formation and calcium influx. We propose that these events can contribute to fast platelet clearance in vivo in patients refractory to platelet transfusions with HLA alloantibodies, who may benefit from functional-platelet matching and treatment with complement inhibitors

    MVA.85A Boosting of BCG and an Attenuated, phoP Deficient M. tuberculosis Vaccine Both Show Protective Efficacy Against Tuberculosis in Rhesus Macaques

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    BACKGROUND: Continuous high global tuberculosis (TB) mortality rates and variable vaccine efficacy of Mycobacterium bovis Bacille Calmette-Guérin (BCG) motivate the search for better vaccine regimes. Relevant models are required to downselect the most promising vaccines entering clinical efficacy testing and to identify correlates of protection. METHODS AND FINDINGS: Here, we evaluated immunogenicity and protection against Mycobacterium tuberculosis in rhesus monkeys with two novel strategies: BCG boosted by modified vaccinia virus Ankara expressing antigen 85A (MVA.85A), and attenuated M. tuberculosis with a disrupted phoP gene (SO2) as a single-dose vaccine. Both strategies were well tolerated, and immunogenic as evidenced by induction of specific IFNgamma responses. Antigen 85A-specific IFNgamma secretion was specifically increased by MVA.85A boosting. Importantly, both MVA.85A and SO2 treatment significantly reduced pathology and chest X-ray scores upon infectious challenge with M. tuberculosis Erdman strain. MVA.85A and SO2 treatment also showed reduced average lung bacterial counts (1.0 and 1.2 log respectively, compared with 0.4 log for BCG) and significant protective effect by reduction in C-reactive protein levels, body weight loss, and decrease of erythrocyte-associated hematologic parameters (MCV, MCH, Hb, Ht) as markers of inflammatory infection, all relative to non-vaccinated controls. Lymphocyte stimulation revealed Ag85A-induced IFNgamma levels post-infection as the strongest immunocorrelate for protection (spearman's rho: -0.60). CONCLUSIONS: Both the BCG/MVA.85A prime-boost regime and the novel live attenuated, phoP deficient TB vaccine candidate SO2 showed significant protective efficacy by various parameters in rhesus macaques. Considering the phylogenetic relationship between macaque and man and the similarity in manifestations of TB disease, these data support further development of these primary and combination TB vaccine candidates

    A paired-kidney allocation study found superior survival with HLA-DR compatible kidney transplants in the Eurotransplant Senior Program

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    The Eurotransplant Senior Program (ESP) has expedited the chance for elderly patients with kidney failure to receive a timely transplant. This current study evaluated survival parameters of kidneys donated after brain death with or without matching for HLA-DR antigens. This cohort study evaluated the period within ESP with paired allocation of 675 kidneys from donors 65 years and older to transplant candidates 65 years and older, the first kidney to 341 patients within the Eurotransplant Senior DR-compatible Program and 334 contralateral kidneys without (ESP) HLA-DR antigen matching. We used Kaplan-Meier estimates and competing risk analysis to assess all cause mortality and kidney graft failure, respectively. The log-rank test and Cox proportional hazards regression were used for comparisons. Within ESP, matching for HLA-DR antigens was associated with a significantly lower five-year risk of mortality (hazard ratio 0.71; 95% confidence interval 0.53-0.95) and significantly lower cause-specific hazards for kidney graft failure and return to dialysis at one year (0.55; 0.35-0.87) and five years (0.73; 0.53-0.99) post-transplant. Allocation based on HLA-DR matching resulted in longer cold ischemia (mean difference 1.00 hours; 95% confidence interval: 0.32-1.68) and kidney offers with a significantly shorter median dialysis vintage of 2.4 versus 4.1 yrs. in ESP without matching. Thus, our allocation based on HLA-DR matching improved five-year patient and kidney allograft survival. Hence, our paired allocation study suggests a superior outcome of HLA-DR matching in the context of old-for-old kidney transplantation.</p

    Activated Platelets in Carotid Artery Thrombosis in Mice Can Be Selectively Targeted with a Radiolabeled Single-Chain Antibody

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    BACKGROUND: Activated platelets can be found on the surface of inflamed, rupture-prone and ruptured plaques as well as in intravascular thrombosis. They are key players in thrombosis and atherosclerosis. In this study we describe the construction of a radiolabeled single-chain antibody targeting the LIBS-epitope of activated platelets to selectively depict platelet activation and wall-adherent non-occlusive thrombosis in a mouse model with nuclear imaging using in vitro and ex vivo autoradiography as well as small animal SPECT-CT for in vivo analysis. METHODOLOGY/PRINCIPAL FINDINGS: LIBS as well as an unspecific control single-chain antibody were labeled with (111)Indium ((111)In) via bifunctional DTPA ( = (111)In-LIBS/(111)In-control). Autoradiography after incubation with (111)In-LIBS on activated platelets in vitro (mean 3866 ± 28 DLU/mm(2), 4010 ± 630 DLU/mm(2) and 4520 ± 293 DLU/mm(2)) produced a significantly higher ligand uptake compared to (111)In-control (2101 ± 76 DLU/mm(2), 1181 ± 96 DLU/mm(2) and 1866 ± 246 DLU/mm(2)) indicating a specific binding to activated platelets; P<0.05. Applying these findings to an ex vivo mouse model of carotid artery thrombosis revealed a significant increase in ligand uptake after injection of (111)In-LIBS in the presence of small thrombi compared to the non-injured side, as confirmed by histology (49630 ± 10650 DLU/mm(2) vs. 17390 ± 7470 DLU/mm(2); P<0.05). These findings could also be reproduced in vivo. SPECT-CT analysis of the injured carotid artery with (111)In-LIBS resulted in a significant increase of the target-to-background ratio compared to (111)In-control (1.99 ± 0.36 vs. 1.1 ± 0.24; P < 0.01). CONCLUSIONS/SIGNIFICANCE: Nuclear imaging with (111)In-LIBS allows the detection of platelet activation in vitro and ex vivo with high sensitivity. Using SPECT-CT, wall-adherent activated platelets in carotid arteries could be depicted in vivo. These results encourage further studies elucidating the role of activated platelets in plaque pathology and atherosclerosis and might be of interest for further developments towards clinical application
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