The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) originated in Wuhan, China in late 2019, and its resulting coronavirus disease, COVID-19, was declared a pandemic by the World ...Health Organization on March 11, 2020. The rapid global spread of COVID-19 represents perhaps the most significant public health emergency in a century. As the pandemic progressed, a continued paucity of evidence on routes of SARS-CoV-2 transmission has resulted in shifting infection prevention and control guidelines between classically-defined airborne and droplet precautions. During the initial isolation of 13 individuals with COVID-19 at the University of Nebraska Medical Center, we collected air and surface samples to examine viral shedding from isolated individuals. We detected viral contamination among all samples, supporting the use of airborne isolation precautions when caring for COVID-19 patients.
Messenger RNAs (mRNAs) encode information in both their primary sequence and their higher order structure. The independent contributions of factors like codon usage and secondary structure to ...regulating protein expression are difficult to establish as they are often highly correlated in endogenous sequences. Here, we used 2 approaches, global inclusion of modified nucleotides and rational sequence design of exogenously delivered constructs, to understand the role of mRNA secondary structure independent from codon usage. Unexpectedly, highly expressed mRNAs contained a highly structured coding sequence (CDS). Modified nucleotides that stabilize mRNA secondary structure enabled high expression across a wide variety of primary sequences. Using a set of eGFP mRNAs with independently altered codon usage and CDS structure, we find that the structure of the CDS regulates protein expression through changes in functional mRNA half-life (i.e., mRNA being actively translated). This work highlights an underappreciated role of mRNA secondary structure in the regulation of mRNA stability.
Abstract Background Experimental and epidemiologic data suggest that among non-pregnant adults, sleep duration may be an important risk factor for chronic disease. Although pregnant women commonly ...complain of poor sleep, few studies have objectively evaluated the quality of sleep in pregnancy or have explored the relationship between sleep disturbances and maternal and perinatal outcomes. Objectives Our objective was to examine the relationship between objectively assessed sleep duration, timing and continuity (measured via wrist actigraphy) and maternal cardiovascular and metabolic morbidity specific to pregnancy. Study Design This was a prospective cohort study of nulliparous women. Women were recruited between 16 0/7 and 21 6/7 weeks’ gestation. They were asked to wear a wrist actigraphy monitor and to complete a daily sleep log for a seven consecutive-day period. The primary sleep exposure variables were the averages of the following over the total valid nights (minimum 5, maximum 7 nights): short sleep duration during the primary sleep period (< 7 hours/night), late sleep midpoint (midpoint between sleep onset and sleep offset > 5 AM), and top quartile of minutes of wake time after sleep onset (WASO) and sleep fragmentation index. The primary outcomes of interest were a composite of hypertensive disorders of pregnancy (mild, severe, or superimposed preeclampsia; eclampsia; or antepartum gestational hypertension) and gestational diabetes (GDM). Chi-square tests were used to assess associations between sleep variables and categorical baseline characteristics. Crude odds ratios and 95% confidence intervals were estimated from univariate logistic regression models to characterize the magnitude of the relationship between sleep characteristics and hypertensive disorders of pregnancy and GDM. For associations that were significant in univariate analysis, multiple logistic regression was used to explore further the association of sleep characteristics with pregnancy outcomes. Results Nine-hundred and one eligible women consented to participate. Of these women 782 submitted valid actigraphy studies. Short sleep duration and a later sleep midpoint were associated with an increased risk of GDM (OR 2.24, 95% CI 1.11, 4.53; OR 2.58, 95% CI 1.24, 5.36, respectively) but not of hypertensive disorders. A model with both sleep duration and sleep midpoint as well as their interaction term revealed that while there was no significant interaction between these exposures, the main effects of both short sleep duration and later sleep midpoint with GDM remained significant (aOR 2.06, 95% CI 1.01, 4.19; aOR 2.37, 95% CI 1.13, 4.97, respectively). Additionally, after adjusting separately for age, BMI and race/ethnicity, both short sleep duration and later sleep midpoint remained associated with GDM. No associations were demonstrated between the sleep quality measures (WASO, sleep fragmentation) and hypertensive disorders or GDM. Conclusions Our results demonstrate a relationship between short sleep duration and later sleep midpoint with GDM. Our data suggest independent contributions of these two sleep characteristics to the risk for GDM in nulliparous women.
Summary
The National Osteoporosis Guideline Group (NOGG) has revised the UK guideline for the assessment and management of osteoporosis and the prevention of fragility fractures in postmenopausal ...women, and men age 50 years and older. Accredited by NICE, this guideline is relevant for all healthcare professionals involved in osteoporosis management.
Introduction
The UK National Osteoporosis Guideline Group (NOGG) first produced a guideline on the prevention and treatment of osteoporosis in 2008, with updates in 2013 and 2017. This paper presents a major update of the guideline, the scope of which is to review the assessment and management of osteoporosis and the prevention of fragility fractures in postmenopausal women, and men age 50 years and older.
Methods
Where available, systematic reviews, meta-analyses and randomised controlled trials were used to provide the evidence base. Conclusions and recommendations were systematically graded according to the strength of the available evidence.
Results
Review of the evidence and recommendations are provided for the diagnosis of osteoporosis, fracture-risk assessment and intervention thresholds, management of vertebral fractures, non-pharmacological and pharmacological treatments, including duration and monitoring of anti-resorptive therapy, glucocorticoid-induced osteoporosis, and models of care for fracture prevention. Recommendations are made for training; service leads and commissioners of healthcare; and for review criteria for audit and quality improvement.
Conclusion
The guideline, which has received accreditation from the National Institute of Health and Care Excellence (NICE), provides a comprehensive overview of the assessment and management of osteoporosis for all healthcare professionals involved in its management. This position paper has been endorsed by the International Osteoporosis Foundation and by the European Society for the Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases.
Dynamic coupling with water contributes to regulating the functional dynamics of a biomolecule. We discuss protein-water dynamics, with emphasis on water that is partially confined, and the role of ...protein-confined water dynamics in allosteric regulation. These properties are illustrated with two systems, a homodimeric hemoglobin from Scapharca inaequivalvis (HbI) and an A
adenosine receptor (A
AR). For HbI, water-protein interactions, long known to contribute to the thermodynamics of cooperativity, are seen to influence the dynamics of the protein not only around the protein-water interface but also into the core of each globule, where dynamic and entropic changes upon ligand binding are coupled to protein-water contact dynamics. Similarly, hydration waters trapped deep inside the core region of A
AR enable the formation of an allosteric network made of water-mediated inter-residue contacts. Extending from the ligand binding pocket to the G-protein binding site, this allosteric network plays key roles in regulating the activity of the receptor.
Summary Background Vitamin D is crucial for maintenance of musculoskeletal health, and might also have a role in extraskeletal tissues. Determinants of circulating 25-hydroxyvitamin D concentrations ...include sun exposure and diet, but high heritability suggests that genetic factors could also play a part. We aimed to identify common genetic variants affecting vitamin D concentrations and risk of insufficiency. Methods We undertook a genome-wide association study of 25-hydroxyvitamin D concentrations in 33 996 individuals of European descent from 15 cohorts. Five epidemiological cohorts were designated as discovery cohorts (n=16 125), five as in-silico replication cohorts (n=9367), and five as de-novo replication cohorts (n=8504). 25-hydroxyvitamin D concentrations were measured by radioimmunoassay, chemiluminescent assay, ELISA, or mass spectrometry. Vitamin D insufficiency was defined as concentrations lower than 75 nmol/L or 50 nmol/L. We combined results of genome-wide analyses across cohorts using Z -score-weighted meta-analysis. Genotype scores were constructed for confirmed variants. Findings Variants at three loci reached genome-wide significance in discovery cohorts for association with 25-hydroxyvitamin D concentrations, and were confirmed in replication cohorts: 4p12 (overall p=1·9×10−109 for rs2282679, in GC ); 11q12 (p=2·1×10−27 for rs12785878, near DHCR7 ); and 11p15 (p=3·3×10−20 for rs10741657, near CYP2R1 ). Variants at an additional locus (20q13, CYP24A1 ) were genome-wide significant in the pooled sample (p=6·0×10−10 for rs6013897). Participants with a genotype score (combining the three confirmed variants) in the highest quartile were at increased risk of having 25-hydroxyvitamin D concentrations lower than 75 nmol/L (OR 2·47, 95% CI 2·20–2·78, p=2·3×10−48 ) or lower than 50 nmol/L (1·92, 1·70–2·16, p=1·0×10−26 ) compared with those in the lowest quartile. Interpretation Variants near genes involved in cholesterol synthesis, hydroxylation, and vitamin D transport affect vitamin D status. Genetic variation at these loci identifies individuals who have substantially raised risk of vitamin D insufficiency. Funding Full funding sources listed at end of paper (see Acknowledgments).
Energy transport during chemical reactions or following photoexcitation in systems of biological molecules is mediated by numerous interfaces that separate chemical groups and molecules. Describing ...and predicting energy transport has been complicated by the inhomogeneous environment through which it occurs, and general rules are still lacking. We discuss recent work on identification of networks for vibrational energy transport in biomolecules and their environment, with focus on the nature of energy transfer across interfaces. Energy transport is influenced both by structure of the biomolecular system as well as by equilibrium fluctuations of nonbonded contacts between chemical groups, biomolecules, and water along the network. We also discuss recent theoretical and computational work on the related topic of thermal transport through molecular interfaces, with focus on systems important in biology as well as relevant experimental studies.
The small heat-shock protein HSP27 is a redox-sensitive molecular chaperone that is expressed throughout the human body. Here, we describe redox-induced changes to the structure, dynamics, and ...function of HSP27 and its conserved α-crystallin domain (ACD). While HSP27 assembles into oligomers, we show that the monomers formed upon reduction are highly active chaperones in vitro, but are susceptible to self-aggregation. By using relaxation dispersion and high-pressure nuclear magnetic resonance (NMR) spectroscopy, we observe that the pair of β-strands that mediate dimerisation partially unfold in the monomer. We note that numerous HSP27 mutations associated with inherited neuropathies cluster to this dynamic region. High levels of sequence conservation in ACDs from mammalian sHSPs suggest that the exposed, disordered interface present in free monomers or oligomeric subunits may be a general, functional feature of sHSPs.
Osteoporotic fracture is a major cause of morbidity and mortality worldwide. Low bone mineral density (BMD) is a major predisposing factor to fracture and is known to be highly heritable. Site-, ...gender-, and age-specific genetic effects on BMD are thought to be significant, but have largely not been considered in the design of genome-wide association studies (GWAS) of BMD to date. We report here a GWAS using a novel study design focusing on women of a specific age (postmenopausal women, age 55-85 years), with either extreme high or low hip BMD (age- and gender-adjusted BMD z-scores of +1.5 to +4.0, n = 1055, or -4.0 to -1.5, n = 900), with replication in cohorts of women drawn from the general population (n = 20,898). The study replicates 21 of 26 known BMD-associated genes. Additionally, we report suggestive association of a further six new genetic associations in or around the genes CLCN7, GALNT3, IBSP, LTBP3, RSPO3, and SOX4, with replication in two independent datasets. A novel mouse model with a loss-of-function mutation in GALNT3 is also reported, which has high bone mass, supporting the involvement of this gene in BMD determination. In addition to identifying further genes associated with BMD, this study confirms the efficiency of extreme-truncate selection designs for quantitative trait association studies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The evolution of massive stars is influenced by the mass lost to stellar winds over their lifetimes. These winds limit the masses of the stellar remnants (such as black holes) that the stars ...ultimately produce. We used radio astrometry to refine the distance to the black hole x-ray binary Cygnus X-1, which we found to be Formula: see text kiloparsecs. When combined with archival optical data, this implies a black hole mass of 21.2 ± 2.2 solar masses, which is higher than previous measurements. The formation of such a high-mass black hole in a high-metallicity system (within the Milky Way) constrains wind mass loss from massive stars.