224 research outputs found
Forage selection preferences of experienced cows and naïve heifers grazing native tallgrass range during winter
Beef Cattle Research, 2011 is known as Cattlemen’s Day, 2011Estimating the nutritive value of a grazing animal’s diet is a significant challenge.
Description of the botanical composition of a grazed diet is vital in that regard. Microhistological
analysis of fecal material has been used for estimating the botanical composition
of wild and domestic ungulate diets since first described by Baumgartner and
Martin in 1939.
Little research has been conducted on the diet selection preferences of multiparous beef
cows compared to primiparous beef cows. We hypothesized that foraging strategies
change as cows age. To that end, our objective was to characterize differences in diet
selection between experienced multiparous and naïve primiparous beef cows grazing
dormant, native tallgrass pastures during winter
Bat lung epithelial cells show greater host species-specific innate resistance than MDCK cells to human and avian influenza viruses
Background
With the recent discovery of novel H17N10 and H18N11 influenza viral RNA in bats and report on high frequency of avian H9 seroconversion in a species of free ranging bats, an important issue to address is the extent bats are susceptible to conventional avian and human influenza A viruses.
Method
To this end, three bat species (Eidolon helvum, Carollia perspicillata and Tadarida brasiliensis) of lung epithelial cells were separately infected with two avian and two human influenza viruses to determine their relative host innate immune resistance to infection.
Results
All three species of bat cells were more resistant than positive control Madin-Darby canine kidney (MDCK) cells to all four influenza viruses. TB1-Lu cells lacked sialic acid α2,6-Gal receptors and were most resistant among the three bat species. Interestingly, avian viruses were relatively more replication permissive in all three bat species of cells than with the use of human viruses which suggest that bats could potentially play a role in the ecology of avian influenza viruses. Chemical inhibition of the JAK-STAT pathway in bat cells had no effect on virus production suggesting that type I interferon signalling is not a major factor in resisting influenza virus infection.
Conclusion
Although all three species of bat cells are relatively more resistant to influenza virus infection than control MDCK cells, they are more permissive to avian than human viruses which suggest that bats could have a contributory role in the ecology of avian influenza viruses
Effects of corn steep liquor supplementation on intake and digestion of tallgrass prairie hay contaminated with sericea lespedeza
Sericea lespedeza (Lespedeza cuneata) is a noxious weed that infests approximately 600,000 acres of native range in Kansas. Intake of sericea lespedeza by grazing beef cattle is poor due to the presence of condensed tannins in the plant. Condensed tannins reduce protein digestion by beef cattle and may also decrease plant palatability because of their astringent nature. Prolific seed production, in combination with little or no grazing pressure, has contributed to the rapid spread of sericea lespedeza in the Flint Hills. Increasing grazing pressure on sericea lespedeza may reduce seed production and slow its advance; however, the presence of condensed tannins inhibit consumption by grazing animals. Reports have indicated that feed-grade polyethylene glycol may inhibit formation of tannin-protein complexes in the rumen, but beef producers have not widely adopted polyethylene glycol because, at the rates necessary to increase intake of sericea lespedeza, it is cost-prohibitive and disallowed by regulations. Therefore, identifying substances that are generally regarded as safe (GRAS) by the U.S. Food and Drug Administration, cost-effective, and that mitigate the consequences of consuming a diet high in tannins is advantageous. Such information could lead to a degree of biological control of this noxious weed using the most economically important grazer (i.e., beef cattle) in the Flint Hills. Preliminary research in our laboratory indicated that corn steep liquor has binding affinity for condensed tannins that is similar to polyethylene glycol. Therefore, the objective of our study was to determine the effects of corn steep liquor supplementation on intake and digestion of tallgrass prairie hay contaminated by sericea lespedeza
Detection of a novel human coronavirus by real-time reverse-transcription polymerase chain reaction
We present two real-time reverse-transcription polymerase chain reaction assays for a novel human coronavirus (CoV), targeting regions upstream of the E gene (upE) or within open reading frame (ORF)1b, respectively. Sensitivity for upE is 3.4 copies per reaction (95% confidence interval (CI): 2.5-6.9 copies) or 291 copies/mL of sample. No cross-reactivity was observed with coronaviruses OC43, NL63, 229E, SARS-CoV, nor with 92 clinical specimens containing common human respiratory viruses. We recommend using upE for screening and ORF1b for confirmation
SARS coronavirus replicase proteins in pathogenesis
Much progress has been made in understanding the role of structural and accessory proteins in the pathogenesis of severe acute respiratory syndrome coronavirus (SARS-CoV) infections. The SARS epidemic also brought new attention to the proteins translated from ORF1a and ORF1b of the input genome RNA, also known as the replicase/transcriptase gene. Evidence for change within the ORF1ab coding sequence during the SARS epidemic, as well as evidence from studies with other coronaviruses, indicates that it is likely that the ORF1ab proteins play roles in virus pathogenesis distinct from or in addition to functions directly involved in viral replication. Recent reverse genetic studies have confirmed that proteins of ORF1ab may be involved in cellular signaling and modification of cellular gene expression, as well as virulence by mechanisms yet to be determined. Thus, the evolution of the ORF1ab proteins may be determined as much by issues of host range and virulence as they are by specific requirements for intracellular replication
A live, impaired-fidelity coronavirus vaccine protects in an aged, immunocompromised mouse model of lethal disease
Live-attenuated RNA virus vaccines are efficacious but subject to reversion to virulence. Among RNA viruses, replication fidelity is recognized as a key determinant of virulence and escape from antiviral therapy; increased fidelity is attenuating for some viruses. Coronavirus replication fidelity is approximately 20-fold greater than that of other RNA viruses and is mediated by a 3′-5′ exonuclease activity (ExoN) that likely functions in RNA proofreading. In this study, we demonstrate that engineered inactivation of SARS-CoV ExoN activity results in a stable mutator phenotype with profoundly decreased fidelity in vivo and attenuation of pathogenesis in young, aged, and immunocompromised mouse models of human SARS. The ExoN inactivation genotype and mutator phenotype are stable and do not revert to virulence, even after serial passage or long-term persistent infection in vivo. Our approach represents a strategy with potential for broad applications for the stable attenuation of coronaviruses and possibly other RNA viruses
Cardiovascular Dysfunction Criteria in Critically Ill Children: The PODIUM Consensus Conference
CONTEXT
Cardiovascular dysfunction is associated with poor outcomes in critically ill children.
OBJECTIVE
We aim to derive an evidence-informed, consensus-based definition of cardiovascular dysfunction in critically ill children.
DATA SOURCES
Electronic searches of PubMed and Embase were conducted from January 1992 to January 2020 using medical subject heading terms and text words to define concepts of cardiovascular dysfunction, pediatric critical illness, and outcomes of interest.
STUDY SELECTION
Studies were included if they evaluated critically ill children with cardiovascular dysfunction and assessment and/or scoring tools to screen for cardiovascular dysfunction and assessed mortality, functional status, organ-specific, or other patient-centered outcomes. Studies of adults, premature infants (≤36 weeks gestational age), animals, reviews and/or commentaries, case series (sample size ≤10), and non-English-language studies were excluded. Studies of children with cyanotic congenital heart disease or cardiovascular dysfunction after cardiopulmonary bypass were excluded.
DATA EXTRACTION
Data were abstracted from each eligible study into a standard data extraction form, along with risk-of-bias assessment by a task force member.
RESULTS
Cardiovascular dysfunction was defined by 9 elements, including 4 which indicate severe cardiovascular dysfunction. Cardiopulmonary arrest (>5 minutes) or mechanical circulatory support independently define severe cardiovascular dysfunction, whereas tachycardia, hypotension, vasoactive-inotropic score, lactate, troponin I, central venous oxygen saturation, and echocardiographic estimation of left ventricular ejection fraction were included in any combination. There was expert agreement (>80%) on the definition.
LIMITATIONS
All included studies were observational and many were retrospective.
CONCLUSIONS
The Pediatric Organ Dysfunction Information Update Mandate panel propose this evidence-informed definition of cardiovascular dysfunction
Case Report: Stepwise Anti-Inflammatory and Anti-SARS-CoV-2 Effects Following Convalescent Plasma Therapy With Full Clinical Recovery.
In these times of COVID-19 pandemic, concern has been raised about the potential effects of SARS-CoV-2 infection on immunocompromised patients, particularly on those receiving B-cell depleting agents and having therefore a severely depressed humoral response. Convalescent plasma can be a therapeutic option for these patients. Understanding the underlying mechanisms of convalescent plasma is crucial to optimize such therapeutic approach. Here, we describe a COVID-19 patient who was deeply immunosuppressed following rituximab (anti-CD20 monoclonal antibody) and concomitant chemotherapy for chronic lymphoid leukemia. His long-term severe T and B cell lymphopenia allowed to evaluate the treatment effects of convalescent plasma. Therapeutic outcome was monitored at the clinical, biological and radiological level. Moreover, anti-SARS-CoV-2 antibody titers (IgM, IgG and IgA) and neutralizing activity were assessed over time before and after plasma transfusions, alongside to SARS-CoV-2 RNA quantification and virus isolation from the upper respiratory tract. Already after the first cycle of plasma transfusion, the patient experienced rapid improvement of pneumonia, inflammation and blood cell counts, which may be related to the immunomodulatory properties of plasma. Subsequently, the cumulative increase in anti-SARS-CoV-2 neutralizing antibodies due to the three additional plasma transfusions was associated with progressive and finally complete viral clearance, resulting in full clinical recovery. In this case-report, administration of convalescent plasma revealed a stepwise effect with an initial and rapid anti-inflammatory activity followed by the progressive SARS-CoV-2 clearance. These data have potential implications for a more extended use of convalescent plasma and future monoclonal antibodies in the treatment of immunosuppressed COVID-19 patients
ANDES: Statistical tools for the ANalyses of DEep Sequencing
<p>Abstract</p> <p>Background</p> <p>The advancements in DNA sequencing technologies have allowed researchers to progress from the analyses of a single organism towards the deep sequencing of a sample of organisms. With sufficient sequencing depth, it is now possible to detect subtle variations between members of the same species, or between mixed species with shared biomarkers, such as the 16S rRNA gene. However, traditional sequencing analyses of samples from largely homogeneous populations are often still based on multiple sequence alignments (MSA), where each sequence is placed along a separate row and similarities between aligned bases can be followed down each column. While this visual format is intuitive for a small set of aligned sequences, the representation quickly becomes cumbersome as sequencing depths cover loci hundreds or thousands of reads deep.</p> <p>Findings</p> <p>We have developed ANDES, a software library and a suite of applications, written in Perl and R, for the statistical ANalyses of DEep Sequencing. The fundamental data structure underlying ANDES is the position profile, which contains the nucleotide distributions for each genomic position resultant from a multiple sequence alignment (MSA). Tools include the root mean square deviation (RMSD) plot, which allows for the visual comparison of multiple samples on a position-by-position basis, and the computation of base conversion frequencies (transition/transversion rates), variation (Shannon entropy), inter-sample clustering and visualization (dendrogram and multidimensional scaling (MDS) plot), threshold-driven consensus sequence generation and polymorphism detection, and the estimation of empirically determined sequencing quality values.</p> <p>Conclusions</p> <p>As new sequencing technologies evolve, deep sequencing will become increasingly cost-efficient and the inter and intra-sample comparisons of largely homogeneous sequences will become more common. We have provided a software package and demonstrated its application on various empirically-derived datasets. Investigators may download the software from Sourceforge at <url>https://sourceforge.net/projects/andestools</url>.</p
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