Can Echocardiographic Findings Predict Falls in Older Persons?

Background. The European and American guidelines state the need for echocardiography in patients with syncope. 50% of older adults with syncope present with a fall. Nonetheless, up to now no data have been published addressing echocardiographic abnormalities in older fallers. Method and Findings. In order to determine the association between echocardiographic abnormalities and falls in older adults, we performed a prospective cohort study, in which 215 new consecutive referrals (age 77.4 SD 6.0) of a geriatric outpatient clinic of a Dutch university hospital were included. During the previous year, 139 had experienced a fall. At baseline, all patients underwent routine two-dimensional and Doppler echocardiography. Falls were recorded during a three-month follow-up. Multivariate adjustment for compounders was performed with a Cox proportional hazards model. 557 patients (26%) fell at least once during follow-up. The adjusted hazard ratio of a fall during follow-up was 135 (95% Cl, 1.08-1.71) for pulmonary hypertension, 1.66 (95% Cl, 1.01 to 2.89) for 4-initial regurgitation, 2.41 (95% Cl, 1.32 to 4.37) for tricuspid regurgitation and 1.76 (95% Cl, 1.03 to 3.01) for pulmonary regurgitation. For aoitic regurgitation the risk of a fall was also increased, but non-significantly. (hazard ratio, 1.57 [95% Cl 0.85 to 2.92]). Trend analysis of the severity of the difterent regurgitations showed a significant relationship for mitral, tricuspid and pulmonary valve regurgitation and pulmonary hypertension. Conclusions. Echo(Dopler)cardiography can be useful in order to identify risk indicators for falling. Presence of pulmonary hypertension or regurgitation of mitral, tricuspid or pulmonary valves was associated with a higher fall risk. Our study indicates that the diagnostic work-up for falls in older adults might be improved by adding an echo(Doppler)cardiogram in selected groups

Determination of the Molecular Basis for a Limited Dimorphism, N417K, in the Plasmodium vivax Duffy-Binding Protein

Invasion of human red blood cells by Plasmodium merozoites is vital for replication and survival of the parasite and, as such, is an attractive target for therapeutic intervention. Merozoite invasion is mediated by specific interactions between parasite ligands and host erythrocyte receptors. The P. vivax Duffy-binding protein (PvDBP) is heavily dependent on the interaction with the human Duffy blood group antigen/receptor for chemokines (DARC) for invasion. Region II of PvDBP contains many allelic polymorphisms likely to have arisen by host immune selection. Successful vaccine development necessitates a deeper understanding of the role of these polymorphisms in both parasite function and evasion of host immunity. A 3D structure of the homologous P. knowlesi DBP predicts that most variant residues are surface-exposed, including N417K, which is a dimorphic residue change that has previously been shown to be part of a linked haplotype that alters DBP sensitivity to inhibitory antibody. In natural isolates only two residues are found at this site, asparagine (N) and lysine (K). Site-directed mutagenesis of residue 417 was used to create a panel of 20 amino acid variants that were then examined for their binding phenotype and response to immune sera. Our results suggest that the observed dimorphism likely arose due to both structural requirements and immune selection pressure. To our knowledge, this is the first exhaustive examination of this kind of the role of a single amino acid residue in antigenic character and binding ability. Our results demonstrate that a single amino acid substitution can dramatically alter both the ability of the PvDBP to bind to human erythrocytes and its antigenic character

Worldwide Genetic Variability of the Duffy Binding Protein: Insights into Plasmodium vivax Vaccine Development

The dependence of Plasmodium vivax on invasion mediated by Duffy binding protein (DBP) makes this protein a prime candidate for development of a vaccine. However, the development of a DBP-based vaccine might be hampered by the high variability of the protein ligand (DBPII), known to bias the immune response toward a specific DBP variant. Here, the hypothesis being investigated is that the analysis of the worldwide DBPII sequences will allow us to determine the minimum number of haplotypes (MNH) to be included in a DBP-based vaccine of broad coverage. For that, all DBPII sequences available were compiled and MNH was based on the most frequent nonsynonymous single nucleotide polymorphisms, the majority mapped on B and T cell epitopes. A preliminary analysis of DBPII genetic diversity from eight malaria-endemic countries estimated that a number between two to six DBP haplotypes (17 in total) would target at least 50% of parasite population circulating in each endemic region. Aiming to avoid region-specific haplotypes, we next analyzed the MNH that broadly cover worldwide parasite population. The results demonstrated that seven haplotypes would be required to cover around 60% of DBPII sequences available. Trying to validate these selected haplotypes per country, we found that five out of the eight countries will be covered by the MNH (67% of parasite populations, range 48–84%). In addition, to identify related subgroups of DBPII sequences we used a Bayesian clustering algorithm. The algorithm grouped all DBPII sequences in six populations that were independent of geographic origin, with ancestral populations present in different proportions in each country. In conclusion, in this first attempt to undertake a global analysis about DBPII variability, the results suggest that the development of DBP-based vaccine should consider multi-haplotype strategies; otherwise a putative P. vivax vaccine may not target some parasite populations

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

The effect of chain architecture of in situ formed copolymers on interfacial morphology of reactive polymer blends

The effect of chain architecture of in situ formed copolymers on the interfacial morphology of reactive polymer blends was&apos; investigated. We found that the chain architectures of copolymers at the interface significantly affected the reaction and interface roughness. Although the amount of in situ formed Y-shaped graft copolymers was smaller than that for diblock copolymers, the interface area generated by the former was larger than that generated by the latter.X1118sciescopu

Morphological development at the interface of polymer/polymer bilayer with an in-situ compatibilizer under electric field

An electric field was applied to reactive bilayer thin films consisting of poly(methyl methacrylate-ran-glycidyl methacrylate) (PMMA-GMA) and polystyrene (PS) with various amounts of monocarboxylic acid end-functionalized PS (PS-mCOOH). The fast growing wavelength (A..) of the interfacial fluctuation under an electric field decreased sharply and approached a steady value with increasing amounts of PS-mCOOH. This is because of the decrease in interfacial tension (gamma) between PMMA-GMA and PS resulting from the formation of PMMA-g-PS copolymers in-situ from the reaction between two functional groups of GMA and mCOOH. The reduction of gamma with increasing amount of PS-mCOOH was verified from a reduction in the dispersed domain size. For a reactive bilayer where Y-shaped graft copolymers were formed, the pillars with flattened top surface were observed even when they did not touch the upper electrode. This result is in contrast to that seen for nonreactive bilayer or even other reactive bilayer where diblock copolymers were generated. Also, the maximum pillar height obtained for the reactive bilayer generating graft copolymers was smaller than that for nonreactive bilayer as well as other reactive bilayer generating diblock copolymers. The mechanism of the growth of the pillars of the reactive bilayer was discussed in terms of the chain architecture of copolymers formed in-situ at the interface.X111110sciescopu