367 research outputs found

    Evidence for Perchlorate-Coupled Molybdenum and Nickel Carbon Monoxide Dehydrogenase CO Oxidation and Characterization of Novel Perchlorate-Reducing Haloarchaea

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    Carbon monoxide (CO) has been exploited as a microbial energy source for much of life’s evolutionary history. A phylogenetically diverse array of microorganisms can oxidize CO using two distinct CO dehydrogenases, molybdenum-dependent (Mo-CODH) and nickel-dependent (Ni-CODH). Aerobes and facultative organisms contain Mo-CODHs which allow them to utilize oxygen as an electron acceptor in addition to alternatives such as nitrate and sulfate. Obligate anaerobic organisms contain Ni-CODHs, which oxidize CO at elevated concentrations, but cannot utilize oxygen. In systems where organic matter deposits are limited or absent, atmospheric trace gases such as CO are thought to assist in supporting the growth and survival of microbial communities. Extraterrestrially, the Martian atmosphere is dominated by CO2, however, CO also has also been documented at substantial levels. Martian regolith contains only trace levels of organic carbon, leaving CO as potentially the most abundant and available substrate capable of supporting near-surface microbial activity. However, Martian regolith also contains perchlorate, while potentially toxic it also serves an abundant potential oxidant. At locations such as the recurrent slope lineae, hypersaline perchlorate-based brines are thought to exist. Though previously unexplored for CO oxidation, chlorine oxyanions may act as suitable electron acceptors, expanding the current range of both Mo-CODH and Ni-CODH CO oxidizing microorganisms. This study used a variety of culture-dependent approaches, cultivating four novel haloarchaea from the Bonneville Salt Flats and surrounding saline soils capable of utilizing CO, ClO4-, or a metabolic coupling. Halovenus carboxidivorans was capable of CO oxidation, while Halobacterium bonnevillei and Halobaculum saliterrae, represent the first microbes capable of nitrate-dependent, perchlorate-coupled CO oxidation at concentrations up to 1 M ClO4-. All three isolates contained Mo-CODHs. The provisional species, Halanaeroarchaeum oxyrespirans, is capable of growth via perchlorate reduction, independently of nitrate, a first for haloarchaeal cryptic perchlorate reduction. Additionally, H. oxyrespirans, can respire oxygen, expanding the known capacities of the genus. Perchlorate-coupled CO oxidation was further expanded to include carboxidotrophic Ni-CODH containing microbes using the thermophilic Firmicute Moorella glycerini as a model organism. Collectively, the isolation of these haloarchaeal cultivars contributed to the expansion of haloarchaeal diversity through both physiological and genomic characterization

    Prevalence and Correlates of Cost-Related Medication Nonadherence to Immunosuppressive Drugs After Heart Transplantation: The International Multicenter Cross-sectional Bright Study

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    Cost-related medication nonadherence (CRMNA) refers to not taking medications as prescribed because of difficulties paying for them.; The aims of this study were (1) to assess the prevalence of CRMNA to immunosuppressants in heart transplant recipients internationally and (2) to determine multilevel correlates (patient, center, and healthcare system levels) of CRMNA.; Using data from the cross-sectional international BRIGHT study, applying multistaged sampling, CRMNA was assessed via 3 self-report items in 1365 patients from 36 heart transplant centers in 11 countries. Cost-related medication nonadherence was defined as any positive answer on any of the 3 items. Healthcare system-level (ie, insurance coverage, out-of-pocket expenditures) and patient-level (ie, intention, perceived financial burden, cost as a barrier, a health belief regarding medication benefits, cost-related self-efficacy, and demographic factors) CRMNA correlates were assessed. Correlates were examined using mixed logistic regression analysis.; Across all study countries, CRMNA had an average prevalence of 2.6% (range, 0% [Switzerland/Brazil] to 9.8% [Australia]) and was positively related to being single (odds ratio, 2.29; 95% confidence interval, 1.17-4.47), perceived financial burden (odds ratio, 2.15; 95% confidence interval, 1.55-2.99), and cost as a barrier (odds ratio, 2.60; 95% confidence interval, 1.66-4.07). Four protective factors were identified: white ethnicity (odds ratio, 0.37; 95% confidence interval, 0.19-0.74), intention to adhere (odds ratio, 0.44; 95% confidence interval, 0.31-0.63), self-efficacy (odds ratio, 0.54; 95% confidence interval, 0.43-0.67), and belief about medication benefit (odds ratio, 0.70; 95% confidence interval, 0.57-0.87). Regarding variability, 81.3% was explained at the patient level; 13.8%, at the center level; and 4.8%, at the country level.; In heart transplant recipients, the CRMNA prevalence varies across countries but is lower than in other chronically ill populations. Identified patient-level correlates are novel (ie, intention to adhere, cost-related barriers, and cost-related self-efficacy) and indicate patient-perceived medication cost burden

    Clinical approach to the diagnosis of autoimmune encephalitis in the pediatric patient

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    Autoimmune encephalitis (AE) is an important and treatable cause of acute encephalitis. Diagnosis of AE in a developing child is challenging because of overlap in clinical presentations with other diseases and complexity of normal behavior changes. Existing diagnostic criteria for adult AE require modification to be applied to children, who differ from adults in their clinical presentations, paraclinical findings, autoantibody profiles, treatment response, and long-term outcomes.A subcommittee of the Autoimmune Encephalitis International Working Group collaborated through conference calls and email correspondence to consider the pediatric-specific approach to AE. The subcommittee reviewed the literature of relevant AE studies and sought additional input from other expert clinicians and researchers.Existing consensus criteria for adult AE were refined for use in children. Provisional pediatric AE classification criteria and an algorithm to facilitate early diagnosis are proposed. There is also discussion about how to distinguish pediatric AE from conditions within the differential diagnosis.Diagnosing AE is based on the combination of a clinical history consistent with pediatric AE and supportive diagnostic testing, which includes but is not dependent on antibody testing. The proposed criteria and algorithm require validation in prospective pediatric cohorts.Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology

    Simian hemorrhagic fever virus infection of rhesus macaques as a model of viral hemorrhagic fever: Clinical characterization and risk factors for severe disease

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    AbstractSimian Hemorrhagic Fever Virus (SHFV) has caused sporadic outbreaks of hemorrhagic fevers in macaques at primate research facilities. SHFV is a BSL-2 pathogen that has not been linked to human disease; as such, investigation of SHFV pathogenesis in non-human primates (NHPs) could serve as a model for hemorrhagic fever viruses such as Ebola, Marburg, and Lassa viruses. Here we describe the pathogenesis of SHFV in rhesus macaques inoculated with doses ranging from 50PFU to 500,000PFU. Disease severity was independent of dose with an overall mortality rate of 64% with signs of hemorrhagic fever and multiple organ system involvement. Analyses comparing survivors and non-survivors were performed to identify factors associated with survival revealing differences in the kinetics of viremia, immunosuppression, and regulation of hemostasis. Notable similarities between the pathogenesis of SHFV in NHPs and hemorrhagic fever viruses in humans suggest that SHFV may serve as a suitable model of BSL-4 pathogens

    O-GlcNAc regulates the mitochondrial integrated stress response by regulating ATF4

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    BackgroundAccumulation of mitochondrial dysfunctional is a hallmark of age-related neurodegeneration including Alzheimer’s disease (AD). Impairment of mitochondrial quality control mechanisms leading to the accumulation of damaged mitochondria and increasing neuronal stress. Therefore, investigating the basic mechanisms of how mitochondrial homeostasis is regulated is essential. Herein, we investigate the role of O-GlcNAcylation, a single sugar post-translational modification, in controlling mitochondrial stress-induced transcription factor Activating Transcription Factor 4 (ATF4). Mitochondrial dysfunction triggers the integrated stress response (ISRmt), in which the phosphorylation of eukaryotic translation initiation factor 2α results in the translation of ATF4.MethodsWe used patient-derived induced pluripotent stem cells, a transgenic mouse model of AD, SH-SY5Y neuroblastoma and HeLa cell-lines to examine the effect of sustained O-GlcNAcase inhibition by Thiamet-G (TMG) on ISRmt using biochemical analyses.ResultsWe show that TMG elevates ATF4 protein levels upon mitochondrial stress in SH-SY5Y neuroblastoma and HeLa cell-lines. An indirect downstream target of ATF4 mitochondrial chaperone glucose-regulated protein 75 (GRP75) is significantly elevated. Interestingly, knock-down of O-GlcNAc transferase (OGT), the enzyme that adds O-GlcNAc, in SH-SY5Y increases ATF4 protein and mRNA expression. Additionally, ATF4 target gene Activating Transcription Factor 5 (ATF5) is significantly elevated at both the protein and mRNA level. Brains isolated from TMG treated mice show elevated levels of ATF4 and GRP75. Importantly, ATF4 occupancy increases at the ATF5 promoter site in brains isolated from TMG treated mice suggesting that O-GlcNAc is regulating ATF4 targeted gene expression. Interestingly, ATF4 and GRP75 are not induced in TMG treated familial Alzheimer’s Disease mice model. The same results are seen in a human in vitro model of AD.ConclusionTogether, these results indicate that in healthy conditions, O-GlcNAc regulates the ISRmt through regulating ATF4, while manipulating O-GlcNAc in AD has no effect on ISRmt

    Household Food Insecurity and Children’s Physical Activity and Sedentary Behaviour in the United States: The Healthy Communities Study

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    OBJECTIVE: To examine associations between household food insecurity and children\u27s physical activity and sedentary behaviours. DESIGN: Secondary analysis was conducted on the Healthy Communities Study, an observational study from 2013 to 2015. Household food insecurity was assessed by two items from the US Department of Agriculture\u27s 18-item US Household Food Security Survey Module. Physical activity was measured using the 7-d Physical Activity Behavior Recall instrument. Data were analyzed using multilevel statistical modelling. SETTING: A total of 130 communities in the USA. PARTICIPANTS: In sum, 5138 US children aged 4-15 years. RESULTS: No associations were found for the relationship between household food insecurity and child physical activity. A significant interaction between household food insecurity and child sex for sedentary behaviors was observed (P = 0·03). CONCLUSIONS: Additional research capturing a more detailed assessment of children\u27s experiences of food insecurity in relation to physical activity is warranted. Future studies may consider adopting qualitative study designs or utilizing food insecurity measures that specifically target child-level food insecurity. Subsequent research may also seek to further explore sub-group analyses by sex

    Economic evaluation of the NET intervention versus guideline dissemination for management of mild head injury in hospital emergency departments

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    Abstract Background Evidence-based guidelines for the management of mild traumatic brain injury (mTBI) in the emergency department (ED) are now widely available, and yet, clinical practice remains inconsistent with the guidelines. The Neurotrauma Evidence Translation (NET) intervention was developed to increase the uptake of guideline recommendations and improve the management of minor head injury in Australian emergency departments (EDs). However, the adoption of this type of intervention typically entails an upfront investment that may or may not be fully offset by improvements in clinical practice, health outcomes and/or reductions in health service utilisation. The present study estimates the cost and cost-effectiveness of the NET intervention, as compared to the passive dissemination of the guideline, to evaluate whether any improvements in clinical practice or health outcomes due to the NET intervention can be obtained at an acceptable cost. Methods and findings Study setting: The NET cluster randomised controlled trial [ACTRN12612001286831]. Study sample: Seventeen EDs were randomised to the control condition and 14 to the intervention. One thousand nine hundred forty-three patients were included in the analysis of clinical practice outcomes (NET sample). A total of 343 patients from 14 control and 10 intervention EDs participated in follow-up interviews and were included in the analysis of patient-reported health outcomes (NET-Plus sample). Outcome measures: Appropriate post-traumatic amnesia (PTA) screening in the ED (primary outcome). Secondary clinical practice outcomes: provision of written information on discharge (INFO) and safe discharge (defined as CT scan appropriately provided plus PTA plus INFO). Secondary patient-reported, post-discharge health outcomes: anxiety (Hospital Anxiety and Depression Scale), post-concussive symptoms (Rivermead), and preference-based health-related quality of life (SF6D). Methods: Trial-based economic evaluations from a health sector perspective, with time horizons set to coincide with the final follow-up for the NET sample (2 months post-intervention) and to 1-month post-discharge for the NET-Plus sample. Results: Intervention and control groups were not significantly different in health service utilisation received in the ED/inpatient ward following the initial mTBI presentation (adjusted mean difference 23.86perpatient;9523.86 per patient; 95%CI − 106, 153;p = 0.719)oroverthelongerfollow−upintheNET−plussample(adjustedmeandifference153; p = 0.719) or over the longer follow-up in the NET-plus sample (adjusted mean difference 341.78 per patient; 95%CI − 58,58, 742; p = 0.094). Savings from lower health service utilisation are therefore unlikely to offset the significantly higher upfront cost of the intervention (mean difference 138.20perpatient;95138.20 per patient; 95%CI 135, 141;p < 0.000).Estimatesoftheneteffectoftheinterventionontotalcost(interventioncostnetofhealthserviceutilisation)suggestthattheinterventionentailssignificantlyhighercoststhanthecontrolcondition(adjustedmeandifference141; p < 0.000). Estimates of the net effect of the intervention on total cost (intervention cost net of health service utilisation) suggest that the intervention entails significantly higher costs than the control condition (adjusted mean difference 169.89 per patient; 95%CI 43,43, 297, p = 0.009). This effect is larger in absolute magnitude over the longer follow-up in the NET-plus sample (adjusted mean difference 505.06;95505.06; 95%CI 96, 915;p = 0.016),mostlyduetoadditionalhealthserviceutilisation.Fortheprimaryoutcome,theNETinterventionismorecostlyandmoreeffectivethanpassivedissemination;entailinganadditionalcostof915; p = 0.016), mostly due to additional health service utilisation. For the primary outcome, the NET intervention is more costly and more effective than passive dissemination; entailing an additional cost of 1246 per additional patient appropriately screened for PTA (169.89/0.1363;Fieller’s95169.89/0.1363; Fieller’s 95%CI 525, $2055). For NET to be considered cost-effective with 95% confidence, decision-makers would need to be willing to trade one quality-adjusted life year (QALY) for 25 additional patients appropriately screened for PTA. While these results reflect our best estimate of cost-effectiveness given the data, it is possible that a NET intervention that has been scaled and streamlined ready for wider roll-out may be more or less cost-effective than the NET intervention as delivered in the trial. Conclusions While the NET intervention does improve the management of mTBI in the ED, it also entails a significant increase in cost and—as delivered in the trial—is unlikely to be cost-effective at currently accepted funding thresholds. There may be a scope for a scaled-up and streamlined NET intervention to achieve a better balance between costs and outcomes. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12612001286831, date registered 12 December 2012

    Generation of Diversity in Streptococcus mutans Genes Demonstrated by MLST

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    Streptococcus mutans, consisting of serotypes c, e, f and k, is an oral aciduric organism associated with the initiation and progression of dental caries. A total of 135 independent Streptococcus mutans strains from caries-free and caries-active subjects isolated from various geographical locations were examined in two versions of an MLST scheme consisting of either 6 housekeeping genes [accC (acetyl-CoA carboxylase biotin carboxylase subunit), gki (glucokinase), lepA (GTP-binding protein), recP (transketolase), sodA (superoxide dismutase), and tyrS (tyrosyl-tRNA synthetase)] or the housekeeping genes supplemented with 2 extracellular putative virulence genes [gtfB (glucosyltransferase B) and spaP (surface protein antigen I/II)] to increase sequence type diversity. The number of alleles found varied between 20 (lepA) and 37 (spaP). Overall, 121 sequence types (STs) were defined using the housekeeping genes alone and 122 with all genes. However π, nucleotide diversity per site, was low for all loci being in the range 0.019–0.007. The virulence genes exhibited the greatest nucleotide diversity and the recombination/mutation ratio was 0.67 [95% confidence interval 0.3–1.15] compared to 8.3 [95% confidence interval 5.0–14.5] for the 6 concatenated housekeeping genes alone. The ML trees generated for individual MLST loci were significantly incongruent and not significantly different from random trees. Analysis using ClonalFrame indicated that the majority of isolates were singletons and no evidence for a clonal structure or evidence to support serotype c strains as the ancestral S. mutans strain was apparent. There was also no evidence of a geographical distribution of individual isolates or that particular isolate clusters were associated with caries. The overall low sequence diversity suggests that S. mutans is a newly emerged species which has not accumulated large numbers of mutations but those that have occurred have been shuffled as a consequence of intra-species recombination generating genotypes which can be readily distinguished by sequence analysis
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