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排序方式: 共有459条查询结果,搜索用时 984 毫秒
371.
The rapid spread of SARS-CoV-2 has significantly impacted the worldwide health system. The SARS-CoV-2 currently bears a remarkably low genetic diversity even though it carries one of the largest RNA genomes among viruses (Rausch et al., 2020). However, the coronaviruses harbor the capability of undergoing recombination at a high rate which can lead to the emergence of novel viral derivatives (Rausch et al., 2020; Gribble et al., 2021). This in turn requires not only global surveillance of SARS-CoV-2 genome in various countries but also careful scrutiny in animal genomic reservoirs. Conventionally, RNA viruses evolve with a high mutation rate, however, the presence of ExoN ribonuclease in SARS-CoV-2 genome has made its case different from other viral species (Gribble et al., 2021). The variables of natural selection which potentially drift the SARS-CoV-2 evolutionary dynamics can be recorded by analyzing deposited sequence genomes for its fitness, transmissibility potential, and pathogenicity (Rouchka et al., 2020). This can potentially provide a way to draw a holistic picture at a national level, while simultaneously providing a comparative overview with worldwide sequences. 相似文献
372.
373.
Giada Sebastiani Rasha Alshaalan Philip Wong Maria Rubino Ayat Salman Peter Metrakos Marc Deschenes Peter Ghali 《PloS one》2015,10(6)
Background & Aims
Non-invasive diagnostic methods for liver fibrosis predict clinical outcomes in viral hepatitis and nonalcoholic fatty liver disease (NAFLD). We specifically evaluated prognostic value of non-invasive fibrosis methods in nonalcoholic steatohepatitis (NASH) against hepatic venous pressure gradient (HVPG) and liver histology.Methods
This was a retrospective cohort study of 148 consecutive patients who met the following criteria: transjugular liver biopsy with HVPG measurement; biopsy-proven NASH; absence of decompensation; AST-to-Platelets Ratio Index (APRI), fibrosis-4 (FIB-4), NAFLD fibrosis score, ultrasound, hepatic steatosis index and Xenon-133 scan available within 6 months from biopsy; a minimum follow-up of 1 year. Outcomes were defined by death, liver transplantation, cirrhosis complications. Kaplan–Meier and Cox regression analyses were employed to estimate incidence and predictors of outcomes, respectively. Prognostic value was expressed as area under the curve (AUC).Results
During a median follow-up of 5 years (interquartile range 3-8), 16.2% developed outcomes, including 7.4% who died or underwent liver transplantation. After adjustment for age, sex, diabetes, the following fibrosis tools predicted outcomes: HVPG >10mmHg (HR=9.60; 95% confidence interval [CI] 3.07-30.12), histologic fibrosis F3-F4 (HR=3.14; 1.41-6.95), APRI >1.5 (HR=5.02; 1.6-15.7), FIB-4 >3.25 (HR=6.33; 1.98-20.2), NAFLD fibrosis score >0.676 (HR=11.9; 3.79-37.4). Prognostic value was as follows: histologic fibrosis stage, AUC=0.85 (95% CI 0.76-0.93); HVPG, AUC=0.81 (0.70-0.91); APRI, AUC=0.89 (0.82-0.96); FIB-4, AUC=0.89 (0.83-0.95); NAFLD fibrosis score, AUC=0.79 (0.69-0.91). Neither histologic steatosis nor non-invasive steatosis methods predicted outcomes (AUC<0.50).Conclusions
Non-invasive methods for liver fibrosis predict outcomes of patients with NASH. They could be used for serial monitoring, risk stratification and targeted interventions. 相似文献374.
375.
Neshika Samarasekera Christine Lerpiniere Arthur F. Fonville Andrew J. Farrall Joanna M. Wardlaw Philip M. White Antonia Torgersen James W. Ironside Colin Smith Rustam Al-Shahi Salman Lothian Audit of the Treatment of Cerebral Haemorrhage collaborators 《PloS one》2015,10(8)
Background
Spontaneous intracerebral haemorrhage is a devastating form of stroke and its incidence increases with age. Obtaining brain tissue following intracerebral haemorrhage helps to understand its cause. Given declining autopsy rates worldwide, the feasibility of establishing an autopsy-based collection and its generalisability are uncertain.Methods
We used multiple overlapping sources of case ascertainment to identify every adult diagnosed with intracerebral haemorrhage between 1st June 2010-31st May 2012, whilst resident in the Lothian region of Scotland. We sought consent from patients with intracerebral haemorrhage (or their nearest relative if the patient lacked mental capacity) to conduct a research autopsy.Results
Of 295 adults with acute intracerebral haemorrhage, 110 (37%) could not be approached to consider donation. Of 185 adults/relatives approached, 91 (49%) consented to research autopsy. There were no differences in baseline demographic variables or markers of intracerebral haemorrhage severity between consenters and non-consenters. Adults who died and became donors (n = 46) differed from the rest of the cohort (n = 249) by being older (median age 80, IQR 76–86 vs. 75, IQR 65–83, p = 0.002) and having larger haemorrhages (median volume 23ml, IQR 13–50 vs. 13ml, IQR 4–40; p = 0.002).Conclusions
Nearly half of those approached consent to brain tissue donation after acute intracerebral haemorrhage. The characteristics of adults who gave consent were comparable to those in an entire community, although those who donate early are older and have larger haemorrhage volumes. 相似文献376.
Rafel Bordas Christophe Lefevre Bart Veeckmans Joe Pitt-Francis Catalin Fetita Christopher E. Brightling David Kay Salman Siddiqui Kelly S. Burrowes 《PloS one》2015,10(12)
The analysis of high-resolution computed tomography (CT) images of the lung is dependent on inter-subject differences in airway geometry. The application of computational models in understanding the significance of these differences has previously been shown to be a useful tool in biomedical research. Studies using image-based geometries alone are limited to the analysis of the central airways, down to generation 6–10, as other airways are not visible on high-resolution CT. However, airways distal to this, often termed the small airways, are known to play a crucial role in common airway diseases such as asthma and chronic obstructive pulmonary disease (COPD). Other studies have incorporated an algorithmic approach to extrapolate CT segmented airways in order to obtain a complete conducting airway tree down to the level of the acinus. These models have typically been used for mechanistic studies, but also have the potential to be used in a patient-specific setting. In the current study, an image analysis and modelling pipeline was developed and applied to a number of healthy (n = 11) and asthmatic (n = 24) CT patient scans to produce complete patient-based airway models to the acinar level (mean terminal generation 15.8 ± 0.47). The resulting models are analysed in terms of morphometric properties and seen to be consistent with previous work. A number of global clinical lung function measures are compared to resistance predictions in the models to assess their suitability for use in a patient-specific setting. We show a significant difference (p < 0.01) in airways resistance at all tested flow rates in complete airway trees built using CT data from severe asthmatics (GINA 3–5) versus healthy subjects. Further, model predictions of airways resistance at all flow rates are shown to correlate with patient forced expiratory volume in one second (FEV1) (Spearman ρ = −0.65, p < 0.001) and, at low flow rates (0.00017 L/s), FEV1 over forced vital capacity (FEV1/FVC) (ρ = −0.58, p < 0.001). We conclude that the pipeline and anatomical models can be used directly in mechanistic modelling studies and can form the basis for future patient-based modelling studies. 相似文献
377.
Mara Kornete Edward S. Mason Julien Girouard Erin I. Lafferty Salman Qureshi Ciriaco A. Piccirillo 《PloS one》2015,10(5)
Type 1 diabetes (T1D) occurs through a breakdown of self-tolerance resulting in the autoimmune destruction of the insulin producing β-islets of the pancreas. A numerical and functional waning of CD4+Foxp3+ regulatory T (Treg) cells, prompted by a pancreatic IL-2 deficiency, accompanies Th1 autoimmunity and T1D progression in non-obese diabetic (NOD) mice. Recently, we identified a dominant subset of intra-islet Treg cells that expresses the ICOS costimulatory receptor and promotes self-tolerance delaying the onset of T1D. ICOS co-stimulation potently enhances IL-2 induced survival and proliferation, and suppressive activity of Treg cells in situ. Here, we propose an ICOS-dependent mechanism of Treg cell homing to the β-islets during pre-diabetes in the NOD model via upregulation of the CXCR3 chemokine receptor. The islet-specific ICOS+ Treg cell subset preferentially expresses CXCR3 in the pancreatic lymph nodes (pLN) in response to Teff cell-mediated pancreatic inflammation, an expression correlating with the onset and magnitude of IFN-γ production by Teff cells in pancreatic sites. We also reveal that intra-pancreatic APC populations and insulin-producing β, but not α nor δ, islet cells secrete the CXCR3 chemokines, CXCL9, 10 and 11, and selectively promote ICOS+CXCR3+ Treg cell chemotaxis in vitro. Strikingly, islet-derived Treg cells also produce these chemokines suggesting an auto-regulation of homing by this subset. Unlike ICOS- cells, ICOS+ Treg cells adopt a Th1-like Treg phenotype while maintaining their suppressive capacity, characterized by expression of T-bet and CXCR3 and production of IFN-γ in the draining pLNs. Finally, in vivo neutralization of IFN-γ blocked Treg cell CXCR3 upregulation evincing its role in regulating expression of this chemokine receptor by Treg cells. Thus, CXCR3-mediated trafficking of Treg cells could represent a mechanism of homeostatic immunoregulation during diabetogeneesis. 相似文献
378.
Neelam Mujaddidi Sobia Nisa Samha Al Ayoubi Yamin Bibi Salman Khan Maimoona Sabir Muhammad Zia Shakil Ahmad Abdul Qayyum 《Saudi Journal of Biological Sciences》2021,28(11):6432-6440
The emergence of multidrug resistance in pathogenic bacteria limits the utilization of available antibiotics. The development of alternate options to treat infectious diseases is the need of the day.The present study was aimed to synthesize, characterize and evaluate the bioactive properties of silver nanoparticles. Endophytic bacterium Bacillus cereus (MT193718) isolated from Berberis lycium was used to synthesize biocompatible silver nanoparticles. Antibacterial properties of AgNPs were evaluated against clinically isolated multidrug-resistant strains of Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae. AgNPs indicated significant antibacterial activity against S. aureus and K. pneumoniae fwith a zone of inhibition of 17 and 18 mm at a concentration of 1000 µg/ mL with minimum inhibitory concentration of 15.6 and 62.5 µg/mL respectively. Significant antioxidant activity with an IC50 value of 9.5 µg/mL was recorded. Biosynthesized AgNPs were found compatible with red blood cells at a concentration of 31.5 µg/ml with no clumping of erythrocytes. The study suggested that AgNPs synthesized by the endophytic bacterium Bacillus cereus are biologically active and can be used as antioxidant and antibacterial agents against drug-resistant bacteria. 相似文献
379.
380.
Studies on the abomasal pathology of immunized and non-immunized sheep infected with Haemonchus contortus 总被引:1,自引:0,他引:1
Five adult ewes and five lambs were repeatedly immunized with weekly doses of 10,000 irradiated Haemonchus contortus L3 before challenge with 100,000 and 10,000 normal larvae respectively. Two groups of non-immunized ewes and lambs were similarly challenged and one animal from each of the four groups killed on days 3, 5, 7, 10 and 24 post-challenge. The cellular changes in the abomasal mucosa were less marked in the non-immunized groups than in the immunized animals and appeared later in the lambs than in the ewes. Thus, in the immunized ewes increases in the numbers of mast cells and eosinophils were evident within five days of challenge whereas similar changes appeared later in the immunized lambs. Also marked lymphoid aggregates at the base of the mucosa and in the submucosa were detected only in the immunized ewes. However, both immunized and non-immunized ewes showed rises in the numbers of IgA plasma cells after challenge which were not evident in either group of lambs. 相似文献