745 research outputs found
The Cell Shape-determining Csd6 Protein from Helicobacter pylori Constitutes a New Family of L,D-Carboxypeptidase
Helicobacter pylori causes gastrointestinal diseases, including gastric cancer. Its high motility in the viscous gastric mucosa facilitates colonization of the human stomach and depends on the helical cell shape and the flagella. In H. pylori, Csd6 is one of the cell shape-determining proteins that play key roles in alteration of cross-linking or by trimming of peptidoglycan muropeptides. Csd6 is also involved in deglycosylation of the flagellar protein FlaA. To better understand its function, biochemical, biophysical, and structural characterizations were carried out. We show that Csd6 has a three-domain architecture and exists as a dimer in solution. The N-terminal domain plays a key role in dimerization. The middle catalytic domain resembles those of L,D-transpeptidases, but its pocket-shaped active site is uniquely defined by the four loops I to IV, among which loops I and III show the most distinct variations from the known L,D-transpeptidases. Mass analyses confirm that Csd6 functions only as an L,D-carboxypeptidase and not as an L,D-transpeptidase. The D-Ala-complexed structure suggests possible binding modes of both the substrate and product to the catalytic domain. The C-terminal nuclear transport factor 2-like domain possesses a deep pocket for possible binding of pseudaminic acid, and in silico docking supports its role in deglycosylation of flagellin. On the basis of these findings, it is proposed that H. pylori Csd6 and its homologs constitute a new family of L,D-carboxypeptidase. This work provides insights into the function of Csd6 in regulating the helical cell shape and motility of H. pylori.1165Ysciescopu
Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke
Background
Recurrent stroke is a frequent, disabling event after ischemic stroke. This study compared
the efficacy and safety of two antiplatelet regimens — aspirin plus extendedrelease
dipyridamole (ASA–ERDP) versus clopidogrel.
Methods
In this double-blind, 2-by-2 factorial trial, we randomly assigned patients to receive
25 mg of aspirin plus 200 mg of extended-release dipyridamole twice daily or to receive
75 mg of clopidogrel daily. The primary outcome was first recurrence of stroke.
The secondary outcome was a composite of stroke, myocardial infarction, or death
from vascular causes. Sequential statistical testing of noninferiority (margin of 1.075),
followed by superiority testing, was planned.
Results
A total of 20,332 patients were followed for a mean of 2.5 years. Recurrent stroke
occurred in 916 patients (9.0%) receiving ASA–ERDP and in 898 patients (8.8%) receiving
clopidogrel (hazard ratio, 1.01; 95% confidence interval [CI], 0.92 to 1.11). The
secondary outcome occurred in 1333 patients (13.1%) in each group (hazard ratio for
ASA–ERDP, 0.99; 95% CI, 0.92 to 1.07). There were more major hemorrhagic events
among ASA–ERDP recipients (419 [4.1%]) than among clopidogrel recipients (365
[3.6%]) (hazard ratio, 1.15; 95% CI, 1.00 to 1.32), including intracranial hemorrhage
(hazard ratio, 1.42; 95% CI, 1.11 to 1.83). The net risk of recurrent stroke or major
hemorrhagic event was similar in the two groups (1194 ASA–ERDP recipients [11.7%],
vs. 1156 clopidogrel recipients [11.4%]; hazard ratio, 1.03; 95% CI, 0.95 to 1.11).
Conclusions
The trial did not meet the predefined criteria for noninferiority but showed similar rates
of recurrent stroke with ASA–ERDP and with clopidogrel. There is no evidence that either
of the two treatments was superior to the other in the prevention of recurrent
stroke. (ClinicalTrials.gov number, NCT00153062.
Differences in Disease Severity but Similar Telomere Lengths in Genetic Subgroups of Patients with Telomerase and Shelterin Mutations
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Rapid production of large-area, transparent and stretchable electrodes using metal nanofibers as wirelessly operated wearable heaters
A rapidly growing interest in wearable electronics has led to the development of stretchable and transparent heating films that can replace the conventional brittle and opaque heaters. Herein, we describe the rapid production of large-area, stretchable and transparent electrodes using electrospun ultra-long metal nanofibers (mNFs) and demonstrate their potential use as wirelessly operated wearable heaters. These mNF networks provide excellent optoelectronic properties (sheet resistance of similar to 1.3 O per sq with an optical transmittance of similar to 90%) and mechanical reliability (90% stretchability). The optoelectronic properties can be controlled by adjusting the area fraction of the mNF networks, which also enables the modulation of the power consumption of the heater. For example, the low sheet resistance of the heater presents an outstanding power efficiency of 0.65 W cm(-2) (with the temperature reaching 250 degrees C at a low DC voltage of 4.5 V), which is similar to 10 times better than the properties of conventional indium tin oxide-based heaters. Furthermore, we demonstrate the wireless fine control of the temperature of the heating film using Bluetooth smart devices, which suggests substantial promise for the application of this heating film in next-generation wearable electronics
Increased Number of Cerebellar Granule Cells and Astrocytes in the Internal Granule Layer in Sheep Following Prenatal Intra-amniotic Injection of Lipopolysaccharide
Chorioamnionitis is an important problem in perinatology today, leading to brain injury and neurological handicaps. However, there are almost no data available regarding chorioamnionitis and a specific damage of the cerebellum. Therefore, this study aimed at determining if chorioamnionitis causes cerebellar morphological alterations. Chorioamnionitis was induced in sheep by the intra-amniotic injection of lipopolysaccharide (LPS) at a gestational age (GA) of 110 days. At a GA of 140 days, we assessed the mean total and layer-specific volume and the mean total granule cell (GCs) and Purkinje cell (PC) number in the cerebelli of LPS-exposed and control animals using high-precision design-based stereology. Astrogliosis was assessed in the gray and white matter (WM) using a glial fibrillary acidic protein staining combined with gray value image analysis. The present study showed an unchanged volume of the total cerebellum as well as the molecular layer, outer and inner granular cell layers (OGL and IGL, respectively), and WM. Interestingly, compared with controls, the LPS-exposed brains showed a statistically significant increase (+20.4%) in the mean total number of GCs, whereas the number of PCs did not show any difference between the two groups. In addition, LPS-exposed animals showed signs of astrogliosis specifically affecting the IGL. Intra-amniotic injection of LPS causes morphological changes in the cerebellum of fetal sheep still detectable at full-term birth. In this study, changes were restricted to the inner granule layer. These cerebellar changes might correspond to some of the motor or non-motor deficits seen in neonates from compromised pregnancies
The Formation of the First Massive Black Holes
Supermassive black holes (SMBHs) are common in local galactic nuclei, and
SMBHs as massive as several billion solar masses already exist at redshift z=6.
These earliest SMBHs may grow by the combination of radiation-pressure-limited
accretion and mergers of stellar-mass seed BHs, left behind by the first
generation of metal-free stars, or may be formed by more rapid direct collapse
of gas in rare special environments where dense gas can accumulate without
first fragmenting into stars. This chapter offers a review of these two
competing scenarios, as well as some more exotic alternative ideas. It also
briefly discusses how the different models may be distinguished in the future
by observations with JWST, (e)LISA and other instruments.Comment: 47 pages with 306 references; this review is a chapter in "The First
Galaxies - Theoretical Predictions and Observational Clues", Springer
Astrophysics and Space Science Library, Eds. T. Wiklind, V. Bromm & B.
Mobasher, in pres
The Evolution of Compact Binary Star Systems
We review the formation and evolution of compact binary stars consisting of
white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and
BHs are thought to be the primary astrophysical sources of gravitational waves
(GWs) within the frequency band of ground-based detectors, while compact
binaries of WDs are important sources of GWs at lower frequencies to be covered
by space interferometers (LISA). Major uncertainties in the current
understanding of properties of NSs and BHs most relevant to the GW studies are
discussed, including the treatment of the natal kicks which compact stellar
remnants acquire during the core collapse of massive stars and the common
envelope phase of binary evolution. We discuss the coalescence rates of binary
NSs and BHs and prospects for their detections, the formation and evolution of
binary WDs and their observational manifestations. Special attention is given
to AM CVn-stars -- compact binaries in which the Roche lobe is filled by
another WD or a low-mass partially degenerate helium-star, as these stars are
thought to be the best LISA verification binary GW sources.Comment: 105 pages, 18 figure
Motion style acupuncture treatment (MSAT) for acute low back pain with severe disability: a multicenter, randomized, controlled trial protocol
<p>Abstract</p> <p>Background</p> <p>Acupuncture is widely-used to treat patients with low back pain, despite insufficient evidence of the technique's efficacy for acute back pain. Motion style acupuncture treatment (MSAT) is a non-traditional acupuncture treatment requiring a patient to exercise while receiving acupuncture. In Korea, MSAT is used to reduce musculoskeletal pain and improve functional status. The study aims to evaluate the effect of MSAT on acute low back pain with severe disability.</p> <p>Methods/Design</p> <p>This study is a multicenter, randomized, active-controlled trial with two parallel arms. Participants with acute low back pain and severe functional disability, defined as an Oswestry Disability Index (ODI) value > 60%, will be randomly allocated to the acupuncture group and the nonsteroidal anti-inflammatory drug (NSAID) injection group. The acupuncture group will receive MSAT and the NSAID injection group will receive an intramuscular injection of diclofenac. All procedures will be limited to one session and the symptoms before and after treatment will be measured by assessors blinded to treatment allocation. The primary outcome will be measured at 30 minutes after treatment using the numerical rating scale (NRS) of low back pain while the patient is moving. Secondary outcomes will be measured at 30 minutes after treatment using the NRS of leg pain, ODI, patient global impression of change, range of motion (ROM) of the lumbar spine, and degrees of straight leg raising (SLR). Post-treatment follow-up will be performed to measure primary and secondary outcomes with the exception of ROM and SLR at 2, 4, and 24 weeks after treatment.</p> <p>Discussion</p> <p>The results of this trial will be discussed.</p> <p>Trial Registration</p> <p>ClinicalTrial.gov <a href="http://www.clinicaltrials.gov/ct2/show/NCT01315561">NCT01315561</a></p
Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015
SummaryBackground The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding Bill & Melinda Gates Foundation
Generation of recombinant single-chain antibodies neutralizing the cytolytic activity of vaginolysin, the main virulence factor of Gardnerella vaginalis
Generated scFvs is the first example of recombinant single-chain antibodies with VLY-neutralizing activity produced in prokaryote expression system. G. vaginalis caused infections continue to be a world-wide problem, therefore neutralizing recombinant antibodies may provide novel therapeutic agents useful in the treatment of bacterial vaginosis and other diseases caused by G. vaginalis
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