1,194 research outputs found
Statin utilisation in a real-world setting: a retrospective analysis in relation to arterial and cardiovascular autonomic function
Randomized trials suggest that statin treatment may lower blood pressure and influence cardiovascular autonomic function (CVAF), but the impact of duration of usage, discontinuation, and adherence to this therapy is unknown. We examined these issues with regard to blood pressure (BP)-related variables in a large, population-based study. Participants were 4942 adults (58% male; aged 50–84 years): 2179 on statin treatment and 2763 untreated. Days of utilization, adherence (proportion of days covered ≥0.8), and discontinuation (non-use for ≥30 days immediately prior to BP measurement) of three statins (atorvastatin, pravastatin, and simvastatin) over a period of up to 2 years was monitored retrospectively from electronic databases. Systolic BP (SBP), diastolic BP (DBP), augmentation index, excess pressure, reservoir pressure, and CVAF (pulse rate and BP variability) parameters were calculated from aortic pressure waveforms derived from suprasystolic brachial measurement. Days of statin treatment had inverse relationships with pulse rate variability parameters in cardiac arrhythmic participants (20–25% lower than in statin non-users) and with most arterial function parameters in everyone. For example, compared to untreated participants, those treated for ≥659 days had 3.0 mmHg lower aortic SBP (P < 0.01). Discontinuation was associated with higher brachial DBP and aortic DBP (for both, β = 2.0 mmHg, P = 0.008). Compared to non-adherent statin users, adherent users had lower levels of brachial SBP, brachial DBP, aortic DBP, aortic SBP, and peak reservoir pressure (β = −1.4 to −2.6 mmHg). In conclusion, in a real-world setting, statin-therapy duration, non-discontinuation and adherence associate inversely with BP variables and, in cardiac arrhythmias, CVAF parameters
Simulating Pathogen Transport within a Naturally Ventilated Hospital Ward
Understanding how airborne pathogens are transported through hospital wards is essential for determining the infection risk to patients and healthcare workers. This study utilizes Computational Fluid Dynamics (CFD) simulations to explore pathogen transport within a six-bed Nightingale hospital ward. Grid independence of a ward model was addressed using the Grid Convergence Index (GCI) from solutions obtained using three fully-structured grids. Pathogens were simulated using source terms in conjunction with a scalar transport equation and a RANS turbulence model. Errors were found to be less than 4% in the prediction of air velocities but an average of 13% was seen in the scalar field. A parametric study into the pathogen release point illustrated that its distribution is strongly influenced by the local velocity field and the degree of mixing present
Factors associated with medication adherence in school-aged children with asthma
Adherence to preventive asthma treatment is poor, particularly in children, yet the factors associated with adherence in this age group are not well understood. Adherence was monitored electronically over 6 months in school-aged children who attended a regional emergency department in New Zealand for an asthma exacerbation and were prescribed twice-daily inhaled corticosteroids. Participants completed questionnaires including assessment of family demographics, asthma responsibility and learning style. Multivariable analysis of factors associated with adherence was conducted. 101 children (mean (range) age 8.9 (6-15) years, 51% male) participated. Median (interquartile range) preventer adherence was 30% (17-48%) of prescribed. Four explanatory factors were identified: female sex (+12% adherence), Asian ethnicity (+19% adherence), living in a smaller household (-3.0% adherence per person in the household), and younger age at diagnosis (+2.7% for every younger year of diagnosis) (all p<0.02). In school-aged children attending the emergency department for asthma, males and non-Asian ethnic groups were at high risk for poor inhaled corticosteroid adherence and may benefit most from intervention. Four factors explained a small proportion of adherence behaviour indicating the difficulty in identifying adherence barriers. Further research is recommended in other similar populations
Prenatal Vitamin D Supplementation and Child Respiratory Health: A Randomised Controlled Trial
PMCID: PMC3691177This 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
Investigating the association between obesity and asthma in 6- to 8-year-old Saudi children:a matched case-control study
Background: Previous studies have demonstrated an association between obesity and asthma, but there remains considerable uncertainty about whether this reflects an underlying causal relationship. Aims: To investigate the association between obesity and asthma in pre-pubertal children and to investigate the roles of airway obstruction and atopy as possible causal mechanisms. Methods: We conducted an age- and sex-matched case–control study of 1,264 6- to 8-year-old schoolchildren with and without asthma recruited from 37 randomly selected schools in Madinah, Saudi Arabia. The body mass index (BMI), waist circumference and skin fold thickness of the 632 children with asthma were compared with those of the 632 control children without asthma. Associations between obesity and asthma, adjusted for other potential risk factors, were assessed separately in boys and girls using conditional logistic regression analysis. The possible mediating roles of atopy and airway obstruction were studied by investigating the impact of incorporating data on sensitisation to common aeroallergens and measurements of lung function. Results: BMI was associated with asthma in boys (odds ratio (OR)=1.14, 95% confidence interval (CI), 1.08–1.20; adjusted OR=1.11, 95% CI, 1.03–1.19) and girls (OR=1.37, 95% CI, 1.26–1.50; adjusted OR=1.38, 95% CI, 1.23–1.56). Adjusting for forced expiratory volume in 1 s had a negligible impact on these associations, but these were attenuated following adjustment for allergic sensitisation, particularly in girls (girls: OR=1.25; 95% CI, 0.96–1.60; boys: OR=1.09, 95% CI, 0.99–1.19). Conclusions: BMI is associated with asthma in pre-pubertal Saudi boys and girls; this effect does not appear to be mediated through respiratory obstruction, but in girls this may at least partially be mediated through increased risk of allergic sensitisation
Nut production in Bertholletia excelsa across a logged forest mosaic: implications for multiple forest use
Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world’s most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1–2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich forests, when a buffer zone cannot be observed, low logging intensities should be implemented. The sustainability of this integrated management system will ultimately depend on a complex series of socioeconomic and ecological interactions. Yet we submit that our study provides an important initial step in understanding the compatibility of timber harvesting with a high value NTFP, potentially allowing for diversification of forest use strategies in Amazonian Perù
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Rarity of monodominance in hyperdiverse Amazonian forests.
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
Transtorno autístico e doença celíaca : sem evidências de associação
Objective: To evaluate the possible association between celiac disease (CD) and/or gluten sensitivity (GS) and autism spectrum disorder
(ASD). Methods: Occurrences of CD were determined in a group of children and adolescents affected by ASD and, conversely, occurrences
of ASD were assessed in a group of biopsy-proven celiac patients. To detect the possible existence of GS, the levels of antigliadin antibodies in ASD patients were assessed and compared with the levels in a group of non-celiac children. Results: The prevalence of CD or GS in
ASD patients was not greater than in groups originating from the same geographical area. Similarly the prevalence of ASD was not greater
than in a group of biopsy-proven CD patients. Conclusion: No statistically demonstrable association was found between CD or GS and ASD.
Consequently, routine screening for CD or GS in all patients with ASD is, at this moment, neither justifed nor cost-effective. ___________________________________________________________________________________ RESUMOObjetivo: Avaliar a possível associação entre doença celíaca (DC) e/ou sensibilidade ao glúten (SG) e transtorno do espectro autista (TEA).
Métodos: Ocorrências de DC foram determinadas em um grupo de crianças e adolescentes afetados pelo TEA e a ocorrência d TEA foi
avaliada em um grupo de pacientes com DC comprovada por biópsia. Para detectar a possível existência de SG, foram determinados níveis
de anticorpos antigliadina em pacientes com TEA e comparados ao grupo de crianças sem a doença celíaca. Resultados: A prevalência de
DC ou SG não foi maior no grupo de pacientes com TEA quando comparada a grupos de indivíduos originários da mesma região geográfca.
De modo similar, a prevalência do TEA não foi maior ao ser comparada ao grupo de pacientes com DC. Conclusão: Não houve associação
estatisticamente demonstrável entre DC ou SG e TEA. Consequentemente, não são justifcáveis, no momento, exames de rotina para detecção de DC ou SG em pacientes com TEA
Increasing body mass index from age 5 to 14 years predicts asthma among adolescents: evidence from a birth cohort study
Background:Obesity and asthma are common disorders, and the prevalence of both has increased in recent decades. It has been suggested that increases in the prevalence of obesity might in part explain the increase in asthma prevalence. This study aims to examine the prospective association between change in body mass index (BMI) z-score between ages 5 and 14 years and asthma symptoms at 14 years. Methods:Data was taken from the Mater University Study of Pregnancy and its outcomes (MUSP), a birth cohort of 7223 mothers and children started in Brisbane (Australia) in 1981. BMI was measured at age 5 and 14 years. Asthma was assessed from maternal reports of symptoms at age 5 and 14 years. In this study analyses were conducted on 2911 participants who had information on BMI and asthma at both ages. Results: BMI z-score at age 14 and the change in BMI z-score from age 5 to 14–years were positively associated with asthma symptoms at age 14 years, whereas BMI z-score at age 5 was not associated with asthma at age 14. Adjustment for a range of early-life exposures did not substantially alter these findings. The association between change in BMI z-score with asthma symptoms at 14 years appeared stronger for male subjects compared with female subjects but there was no statistical evidence for a sex difference (P=0.36). Conclusions: Increase in BMI z-score between age 5 and 14 years is associated with increased risk of asthma symptoms in adolescence
Sialic Acid Glycobiology Unveils Trypanosoma cruzi Trypomastigote Membrane Physiology.
Trypanosoma cruzi, the flagellate protozoan agent of Chagas disease or American trypanosomiasis, is unable to synthesize sialic acids de novo. Mucins and trans-sialidase (TS) are substrate and enzyme, respectively, of the glycobiological system that scavenges sialic acid from the host in a crucial interplay for T. cruzi life cycle. The acquisition of the sialyl residue allows the parasite to avoid lysis by serum factors and to interact with the host cell. A major drawback to studying the sialylation kinetics and turnover of the trypomastigote glycoconjugates is the difficulty to identify and follow the recently acquired sialyl residues. To tackle this issue, we followed an unnatural sugar approach as bioorthogonal chemical reporters, where the use of azidosialyl residues allowed identifying the acquired sugar. Advanced microscopy techniques, together with biochemical methods, were used to study the trypomastigote membrane from its glycobiological perspective. Main sialyl acceptors were identified as mucins by biochemical procedures and protein markers. Together with determining their shedding and turnover rates, we also report that several membrane proteins, including TS and its substrates, both glycosylphosphatidylinositol-anchored proteins, are separately distributed on parasite surface and contained in different and highly stable membrane microdomains. Notably, labeling for α(1,3)Galactosyl residues only partially colocalize with sialylated mucins, indicating that two species of glycosylated mucins do exist, which are segregated at the parasite surface. Moreover, sialylated mucins were included in lipid-raft-domains, whereas TS molecules are not. The location of the surface-anchored TS resulted too far off as to be capable to sialylate mucins, a role played by the shed TS instead. Phosphatidylinositol-phospholipase-C activity is actually not present in trypomastigotes. Therefore, shedding of TS occurs via microvesicles instead of as a fully soluble form
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