520 research outputs found
Genotype List String: a grammar for describing HLA and KIR genotyping results in a text string
Knowledge of an individual's human leukocyte antigen (HLA) genotype is essential for modern medical genetics, and is crucial for hematopoietic stem cell and solid-organ transplantation. However, the high levels of polymorphism known for the HLA genes make it difficult to generate an HLA genotype that unambiguously identifies the alleles that are present at a given HLA locus in an individual. For the last 20 years, the histocompatibility and immunogenetics community has recorded this HLA genotyping ambiguity using allele codes developed by the National Marrow Donor Program (NMDP). While these allele codes may have been effective for recording an HLA genotyping result when initially developed, their use today results in increased ambiguity in an HLA genotype, and they are no longer suitable in the era of rapid allele discovery and ultra-high allele polymorphism. Here, we present a text string format capable of fully representing HLA genotyping results. This Genotype List (GL) String format is an extension of a proposed standard for reporting killer-cell immunoglobulin-like receptor (KIR) genotype data that can be applied to any genetic data that use a standard nomenclature for identifying variants. The GL String format uses a hierarchical set of operators to describe the relationships between alleles, lists of possible alleles, phased alleles, genotypes, lists of possible genotypes, and multilocus unphased genotypes, without losing typing information or increasing typing ambiguity. When used in concert with appropriate tools to create, exchange, and parse these strings, we anticipate that GL Strings will replace NMDP allele codes for reporting HLA genotypes
Sequestration of Martian CO2 by mineral carbonation
Carbonation is the water-mediated replacement of silicate minerals, such as olivine, by carbonate, and is commonplace in the Earth’s crust. This reaction can remove significant quantities of CO2 from the atmosphere and store it over geological timescales. Here we present the first direct evidence for CO2 sequestration and storage on Mars by mineral carbonation. Electron beam imaging and analysis show that olivine and a plagioclase feldspar-rich mesostasis in the Lafayette meteorite have been replaced by carbonate. The susceptibility of olivine to replacement was enhanced by the presence of smectite veins along which CO2-rich fluids gained access to grain interiors. Lafayette was partially carbonated during the Amazonian, when liquid water was available intermittently and atmospheric CO2 concentrations were close to their present-day values. Earlier in Mars’ history, when the planet had a much thicker atmosphere and an active hydrosphere, carbonation is likely to have been an effective mechanism for sequestration of CO2
Planet Populations as a Function of Stellar Properties
Exoplanets around different types of stars provide a window into the diverse
environments in which planets form. This chapter describes the observed
relations between exoplanet populations and stellar properties and how they
connect to planet formation in protoplanetary disks. Giant planets occur more
frequently around more metal-rich and more massive stars. These findings
support the core accretion theory of planet formation, in which the cores of
giant planets form more rapidly in more metal-rich and more massive
protoplanetary disks. Smaller planets, those with sizes roughly between Earth
and Neptune, exhibit different scaling relations with stellar properties. These
planets are found around stars with a wide range of metallicities and occur
more frequently around lower mass stars. This indicates that planet formation
takes place in a wide range of environments, yet it is not clear why planets
form more efficiently around low mass stars. Going forward, exoplanet surveys
targeting M dwarfs will characterize the exoplanet population around the lowest
mass stars. In combination with ongoing stellar characterization, this will
help us understand the formation of planets in a large range of environments.Comment: Accepted for Publication in the Handbook of Exoplanet
Successful thrombolysis with recombinant tissue plasminogen activator after antagonizing dabigatran by idarucizumab: a case report
A SELEX-Screened Aptamer of Human Hepatitis B Virus RNA Encapsidation Signal Suppresses Viral Replication
Background: The specific interaction between hepatitis B virus (HBV) polymerase (P protein) and the e RNA stem-loop on pregenomic (pg) RNA is crucial for viral replication. It triggers both pgRNA packaging and reverse transcription and thus represents an attractive antiviral target. RNA decoys mimicking e in P protein binding but not supporting replication might represent novel HBV inhibitors. However, because generation of recombinant enzymatically active HBV polymerase is notoriously difficult, such decoys have as yet not been identified. Methodology/Principal Findings: Here we used a SELEX approach, based on a new in vitro reconstitution system exploiting a recombinant truncated HBV P protein (miniP), to identify potential e decoys in two large e RNA pools with randomized upper stem. Selection of strongly P protein binding RNAs correlated with an unexpected strong enrichment of A residues. Two aptamers, S6 and S9, displayed particularly high affinity and specificity for miniP in vitro, yet did not support viral replication when part of a complete HBV genome. Introducing S9 RNA into transiently HBV producing HepG2 cells strongly suppressed pgRNA packaging and DNA synthesis, indicating the S9 RNA can indeed act as an e decoy that competitively inhibits P protein binding to the authentic e signal on pgRNA. Conclusions/Significance: This study demonstrates the first successful identification of human HBV e aptamers by an in vitro SELEX approach. Effective suppression of HBV replication by the S9 aptamer provides proof-of-principle for the abilit
Circumstellar disks and planets. Science cases for next-generation optical/infrared long-baseline interferometers
We present a review of the interplay between the evolution of circumstellar
disks and the formation of planets, both from the perspective of theoretical
models and dedicated observations. Based on this, we identify and discuss
fundamental questions concerning the formation and evolution of circumstellar
disks and planets which can be addressed in the near future with optical and
infrared long-baseline interferometers. Furthermore, the importance of
complementary observations with long-baseline (sub)millimeter interferometers
and high-sensitivity infrared observatories is outlined.Comment: 83 pages; Accepted for publication in "Astronomy and Astrophysics
Review"; The final publication is available at http://www.springerlink.co
Use of recommended medications after myocardial infarction in Austria
Guidelines recommend long-term use of beta-blockers (BB), statins, and angiotensin-converting-enzyme-inhibitors or angiotensin-receptor-blockers (ACEI/ARB) after myocardial infarction (MI), but data on their use after discharge are scarce. From Austrian sickness funds claims, we identified all acute MI patients who were discharged within 30 days and who survived ≥120 days after MI in 2004. We ascertained outpatient use of ACEI/ARBs, BBs, statins, and aspirin from all filled prescriptions between discharge and 120 days post MI. Comorbidities were ascertained from use of indicator drugs during the preceding year. Multivariate logistic regression was used to evaluate the independent determinants of study drug use. We evaluated 4,105 MI patients, whose mean age was 68.8 (±13.2) years; 59.5% were men. Within 120 days after MI, 67% filled prescriptions for ACE/ARBs, 74% for BBs, and 67% for statin. While 41% received all these classes and 34% two, 25% of patients received only one or none of these drugs. Older age and presence of severe mental illness were associated with lower use of all drug classes. Diabetics had greater ACEI/ARB use. Fewer BBs were used in patients with obstructive lung disease. Statin use was lower in patients using treatment for congestive heart failure (all P < 0.001). We conclude that recommended medications were underused in Austrian MI survivors. Quality indicators should be established and interventions be implemented to ensure maximum secondary prevention after MI
Complete hepatitis B virus genome analysis in HBsAg positive mothers and their infants with fulminant hepatitis B
BACKGROUND: After perinatal transmission of hepatitis B virus, infants of anti-HBe positive HBsAg carrier mothers may develop fulminant hepatitis B. Previously it has been suggested, that fulminant hepatitis B in adults was associated with specific mutations in the HBV-genome. The aim of this study was to investigate, whether specific viral variants are associated with fulminant hepatitis B in young infants. METHODS: The complete HBV-genomes of five mothers and their infants with fulminant hepatitis were isolated from the sera, amplified and directly sequenced. RESULTS: Between 6 and 43 base pair exchanges between the HBV genomes of the infants and their mothers were identified. The mutations spread over the entire virus genome. Nucleotide exchanges in the basic core promotor and precore region were identified in all cases. A heterogeneous virus population was detected in four mothers. CONCLUSIONS: Many new mutations were proved to emerge during fulminant hepatitis B in infants, who had been perinatally infected. HBeAg negative variants were the predominant population in all children, whereas these mutants could only be detected as subpopulations in four mothers. The data suggest that the selection of a specific HBeAg negative viral strain may be associated with the development of fulminant hepatitis B in children
Multidisciplinary care planning in the primary care management of completed stroke: a systematic review
Background: Chronic disease management requires input from multiple health professionals, both specialist and primary care providers. This study sought to assess the impact of co-ordinated multidisciplinary care in primary care, represented by the delivery of formal care planning by primary care teams or shared across primary-secondary teams, on outcomes in stroke, relative to usual care
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