158 research outputs found
A critical role for ATF2 transcription factor in the regulation of E-selectin expression in response to non-endotoxin components of Neisseria meningitidis
Vascular injury is a serious complication of sepsis due to the gram-negative bacterium Neisseria meningitidis. One of the critical early steps in initiating this injury is via the interaction of leucocytes, particularly neutrophils, with adhesion molecules expressed on inflamed endothelium. We have previously demonstrated that both lipopolysaccharide (LPS) and non-LPS components of meningococci can induce very high levels of expression of the vascular endothelial cell adhesion molecule E-selectin, which is critical for early tethering and capture of neutrophils onto endothelium under flow. Using an LPS-deficient strain of meningococcus, we showed that very high levels of expression can be induced in primary endothelial cells, even in the context of weak activation of the major host signal transduction factor [nuclear factor-κB (NF-κB)]. In this study, we show that the particular propensity for N. meningitidis to induce high levels of expression is regulated at a transcriptional level, and demonstrate a significant role for phosphorylation of the ATF2 transcription factor, likely via mitogen-activated protein (MAP) kinases, on the activity of the E-selectin promoter. Furthermore, inhibition of E-selectin expression in response to the lpxA- strain by a p38 inhibitor indicates a significant role of a p38-dependent MAPK signalling pathway in ATF2 activation. Collectively, these data highlight the role that LPS and other bacterial components have in modulating endothelial function and their involvement in the pathogenesis of meningococcal sepsis. Better understanding of these multiple mechanisms induced by complex stimuli such as bacteria, and the specific inflammatory pathways they activate, may lead to improved, focused interventions in both meningococcal and potentially bacterial sepsis more generally
Automated Reasoning and Presentation Support for Formalizing Mathematics in Mizar
This paper presents a combination of several automated reasoning and proof
presentation tools with the Mizar system for formalization of mathematics. The
combination forms an online service called MizAR, similar to the SystemOnTPTP
service for first-order automated reasoning. The main differences to
SystemOnTPTP are the use of the Mizar language that is oriented towards human
mathematicians (rather than the pure first-order logic used in SystemOnTPTP),
and setting the service in the context of the large Mizar Mathematical Library
of previous theorems,definitions, and proofs (rather than the isolated problems
that are solved in SystemOnTPTP). These differences poses new challenges and
new opportunities for automated reasoning and for proof presentation tools.
This paper describes the overall structure of MizAR, and presents the automated
reasoning systems and proof presentation tools that are combined to make MizAR
a useful mathematical service.Comment: To appear in 10th International Conference on. Artificial
Intelligence and Symbolic Computation AISC 201
Digestive tract morphometry and breast muscle microstructure in spent breeder ducks maintainedin a conservation programme of genetic resources
The objective of this study was to compare three genetic groups of ducks: P9
(French Pekin), K2 (bred from wild mallards – Anas platyrhynchos L.
and Pekin duck), and KhO1 (hybrid of Khaki Campbell drake and Orpington Fauve
duck) after two breeding seasons for body weight and length, length of
intestine and its segments, percentage of other internal organs, and breast
muscle microstructure. The study used 60Â ducks, 20Â birds (10Â males and
10Â females) from each genetic group. At 110Â weeks of age, P9 ducks exhibited
significantly (p<0.05) greater body weight and length, and length
of intestine and its segments (except for colon length) compared to K2 and
KhO1 ducks. KhO1 ducks had significantly shorter jejunum and ileum compared
to K2 birds. The lighter K2 and KhO1 ducks had significantly greater relative
length of intestine and its segments. In P9 ducks, liver, heart, and gizzard
were heavier and spleen percentage in body weight significantly lower than in
K2 and KhO1 birds. KhO1 ducks had a significantly higher percentage of
proventriculus compared to the other duck groups. The different genetic
origins of the ducks had no effect on microstructural characteristics of
m. pectoralis superficialis except for perimysium and endomysium
thickness. Our study provided information about differences in the digestive
tract morphometry and breast muscle microstructure of ducks from three
genetic groups after two reproductive seasons, which are maintained in a
conservation programme of genetic resources in Poland.</p
Associations Between Aldosterone-Renin-Ratio and Bone Parameters Derived from Peripheral Quantitative Computed Tomography and Impact Microindentation in Men
Components of the renin–angiotensin–aldosterone system (RAAS) are present on bone cells. One measure of RAAS activity, the aldosterone-renin-ratio (ARR), is used to screen for primary aldosteronism. Associations between ARR and bone mineral density are conflicting. This study investigated associations between ARR and peripheral quantitative computed tomography (pQCT) and impact microindentation (IMI). Male participants (n = 431) were from the Geelong Osteoporosis Study. “Likely” primary aldosteronism was defined as ARR ≥ 70 pmol/mIU. Another group, “possible” primary aldosteronism, was defined as either ARR ≥ 70 pmol/mIU or taking a medication that affects the RAAS, but not a beta blocker, and renin  0.05). There were no associations between ARR or aldosterone and pQCT-derived bone parameters. Men with likely primary aldosteronism had lower bone area, suggesting clinically high levels of ARR may have a negative impact on bone health
Obesity and type 2 diabetes have additive effects on left ventricular remodelling in normotensive patients-a cross sectional study
BackgroundIt is unclear whether obesity and type 2 diabetes (T2D), either alone or in combination, induce left ventricular hypertrophy (LVH) independent of hypertension. In the current study, we provide clarity on this issue by rigorously analysing patient left ventricular (LV) structure via clinical indices and via LV geometric patterns (more commonly used in research settings). Importantly, our sample consisted of hypertensive patients that are routinely screened for LVH via echocardiography and normotensive patients that would normally be deemed low risk with no further action required.MethodsThis cross sectional study comprised a total of 353 Caucasian patients, grouped based on diagnosis of obesity, T2D and hypertension, with normotensive obese patients further separated based on metabolic health. Basic metabolic parameters were collected and LV structure and function were assessed via transthoracic echocardiography. Multivariable logistic and linear regression analyses were used to identify predictors of LVH and diastolic dysfunction.ResultsMetabolically healthy normotensive obese patients exhibited relatively low risk of LVH. However, normotensive metabolically non-healthy obese, T2D and obese/T2D patients all presented with reduced normal LV geometry that coincided with increased LV concentric remodelling. Furthermore, normotensive patients presenting with both obesity and T2D had a higher incidence of concentric hypertrophy and grade 3 diastolic dysfunction than normotensive patients with either condition alone, indicating an additive effect of obesity and T2D. Alarmingly these alterations were at a comparable prevalence to that observed in hypertensive patients. Interestingly, assessment of LVPWd, a traditional index of LVH, underestimated the presence of LV concentric remodelling. The implications for which were demonstrated by concentric remodelling and concentric hypertrophy strongly associating with grade 1 and 3 diastolic dysfunction respectively, independent of sex, age and BMI. Finally, pulse pressure was identified as a strong predictor of LV remodelling within normotensive patients.ConclusionsThese findings show that metabolically non-healthy obese, T2D and obese/T2D patients can develop LVH independent of hypertension. Furthermore, that LVPWd may underestimate LV remodelling in these patient groups and that pulse pressure can be used as convenient predictor of hypertrophy status.<br /
Trials and tribulations of recruiting 2,000 older women onto a clinical trial investigating falls and fractures : vital D study
Background Randomised, placebo-controlled trials are needed to provide evidence demonstrating safe, effective interventions that reduce falls and fractures in the elderly. The quality of a clinical trial is dependent on successful recruitment of the target participant group. This paper documents the successes and failures of recruiting over 2,000 women aged at least 70 years and at higher risk of falls or fractures onto a placebo-controlled trial of six years duration. The characteristics of study participants at baseline are also described for this study.Methods The Vital D Study recruited older women identified at high risk of fracture through the use of an eligibility algorithm, adapted from identified risk factors for hip fracture. Participants were randomised to orally receive either 500,000 IU vitamin D3 (cholecalciferol) or placebo every autumn for five consecutive years. A variety of recruitment strategies were employed to attract potential participants.Results Of the 2,317 participants randomised onto the study, 74% (n = 1716/2317) were consented onto the study in the last five months of recruiting. This was largely due to the success of a targeted mail-out. Prior to this only 541 women were consented in the 18 months of recruiting. A total of 70% of all participants were recruited as a result of targeted mail-out. The response rate from the letters increased from 2 to 7% following revision of the material by a public relations company. Participant demographic or risk factor profile did not differ between those recruited by targeted mail-outs compared with other methods.Conclusion The most successful recruitment strategy was the targeted mail-out and the response rate was no higher in the local region where the study had extensive exposure through other recruiting strategies. The strategies that were labour-intensive and did not result in successful recruitment include the activities directed towards the GP medical centres. Comprehensive recruitment programs employ overlapping strategies simultaneously with ongoing assessment of recruitment rates. In our experience, and others direct mail-outs work best although rights to privacy must be respected. <br /
Environmentally Acquired Bacillus and Their Role in C. difficile Colonization Resistance
Clostridioides difficile is an environmentally acquired, anaerobic, spore-forming bacterium which ordinarily causes disease following antibiotic-mediated dysbiosis of the intestinal microbiota. Although much is understood regarding the life cycle of C. difficile, the fate of C. difficile spores upon ingestion remains unclear, and the underlying factors that predispose an individual to colonization and subsequent development of C. difficile infection (CDI) are not fully understood. Here, we show that Bacillus, a ubiquitous and environmentally acquired, spore-forming bacterium is associated with colonization resistance to C. difficile. Using animal models, we first provide evidence that animals housed under conditions that mimic reduced environmental exposure have an increased susceptibility to CDI, correlating with a loss in Bacillus. Lipopeptide micelles (~10 nm) produced by some Bacilli isolated from the gastro-intestinal (GI)-tract and shown to have potent inhibitory activity to C. difficile have recently been reported. We show here that these micelles, that we refer to as heterogenous lipopeptide lytic micelles (HELMs), act synergistically with components present in the small intestine to augment inhibitory activity against C. difficile. Finally, we show that provision of HELM-producing Bacillus to microbiota-depleted animals suppresses C. difficile colonization thereby demonstrating the significant role played by Bacillus in colonization resistance. In the wider context, our study further demonstrates the importance of environmental microbes on susceptibility to pathogen colonization
Erratum to: Obesity and type 2 diabetes have additive effects on left ventricular remodelling in normotensive patients-a cross sectional study
Characteristics of Early Paget's Disease in SQSTM1 Mutation Carriers: Baseline Analysis of the ZiPP Study Cohort
Mutations in SQSTM1 are strongly associated with Paget's disease of bone (PDB), but little is known about the clinical characteristics of those with early disease. Radionuclide bone scans, biochemical markers of bone turnover, and clinical characteristics were analyzed in SQSTM1 mutation carriers who took part in the Zoledronic acid in the Prevention of Paget's disease (ZiPP) study. We studied 222 individuals, of whom 54.9% were female, with mean ± SE age of 50.1 ± 0.6 years. Twelve SQSTM1 mutations were observed, including p.Pro392Leu, which was present in 141 of 222 (63.5%) subjects. Bone scan examination revealed evidence of PDB in 20 subjects (9.0%), ten of whom (50%) had a single affected site. Participants with lesions were older than those without lesions but the difference was not significant (53.6 ± 9.1 versus 49.8 ± 8.9; p =.07). The mean age of participants with lesions was not significantly different from the age at which their parents were diagnosed with PDB (55 years versus 59 years, p =.17). All individuals with lesions were asymptomatic. Serum concentrations of total alkaline phosphatase (ALP) normalized to the upper limit of normal in each center were higher in those with lesions (0.75 ± 0.69 versus 0.42 ± 0.29 arbitary units; p <.0001). Similar findings were observed for other biochemical markers of bone turnover, but the sensitivity of ALP and other markers in detecting lesions was poor. Asymptomatic PDB is present in about 9% of SQSTM1 mutation carriers by the fifth decade. Further follow-up of this cohort will provide important information on the natural history of early PDB and its response to treatment. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research
Obesity and type 2 diabetes have additive effects on left ventricular remodelling in normotensive patients-a cross sectional study
- …