Different outcomes of a cardiac rehabilitation programme in functional parameters among myocardial infarction survivors according to ejection fraction

Introduction

Exercise-based cardiac rehabilitation (EBCR) is part of the management of patients who have suffered an acute myocardial infarction (AMI). Patients with a reduced ejection fraction (EF) comprise a higher-risk subgroup and are referred less often for these programmes. This study aimed at assessing the impact of the baseline EF on the functional benefits, as assessed by peak oxygen uptake (pVO₂) and exercise duration, of an EBCR programme in AMI survivors.

Methods

Observational, retrospective cohort study including all patients admitted to a tertiary centre due to an AMI who completed a phase II EBCR programme after discharge, between November 2012 and April 2017. Functional parameters were assessed by a symptom-limited cardiopulmonary exercise test.

Results

A total of 379 patients were included [40.9% with reduced EF (<50%) at discharge]. After the programme, pVO₂ and exercise duration increased significantly (p < 0.001). Patients with a reduced EF had a lower pVO₂ and completed a shorter duration of exercise at the beginning and end of the programme. This group presented a higher increase in pVO₂ (p = 0.001) and exercise duration (p = 0.007). This was maintained after adjusting for age, gender, history of coronary artery disease, number of sessions, Killip classification, arterial hypertension, dyslipidaemia, diabetes mellitus, smoking status and baseline pVO₂.

Conclusion

A phase II EBCR programme was associated with significant improvements in pVO₂ and exercise duration among AMI survivors, irrespective of baseline EF classification. Those with a reduced baseline EF derived an even greater improvement, highlighting the importance of EBCR in this subgroup of patients.

     

Development of LCA benchmarks for Austrian torrent control structures

The International Journal of Life Cycle Assessment - This study emerged from a research project that aimed to develop a Life Cycle Assessment (LCA) model for torrent control structures. This...     

Protist Biodiversity and Biogeography in Lakes From Four Brazilian River–Floodplain Systems

The biodiversity and biogeography of protists inhabiting many ecosystems have been intensely studied using different sequencing approaches, but tropical ecosystems are relatively under‐studied. Here, we sampled planktonic waters from 32 lakes associated with four different river–floodplains systems in Brazil, and sequenced the DNA using a metabarcoding approach with general eukaryotic primers. The lakes were dominated by the largely free‐living Discoba (mostly the Euglenida), Ciliophora, and Ochrophyta. There was low community similarity between lakes even within the same river–floodplain. The protists inhabiting these floodplain systems comprise part of the large and relatively undiscovered diversity in the tropics.     

Characterization of the exoskeleton of the Antarctic king crab Paralomis birsteini

Ocean acidification is projected to inhibit the biogenic production of calcium carbonate skeletons in marine organisms. Antarctic waters represent a natural environment in which to examine the long‐term effects of carbonate undersaturation on calcification in marine predators. King crabs (Decapoda: Anomura: Lithodidae), which currently inhabit the undersaturated environment of the continental slope off Antarctica, are potential invasives on the Antarctic shelf as oceanic temperatures rise. Here, we describe the chemical, physical, and mechanical properties of the exoskeleton of the deep‐water Antarctic lithodid Paralomis birsteini and compare our measurements with two decapod species from shallow water at lower latitudes, Callinectes sapidus (Brachyura: Portunidae) and Cancer borealis (Brachyura: Cancridae). In Paralomis birsteini, crabs deposit proportionally more calcium carbonate in their predatory chelae than their protective carapaces, compared with the other two crab species. When exoskeleton thickness and microhardness were compared between the chelae and carapace, the magnitude of the difference between these body regions was significantly greater in P. birsteini than in the other species tested. Hence, there appeared to be a greater disparity in P. birsteini in overall investment in calcium carbonate structures among regions of the exoskeleton. The imperatives of prey consumption and predator avoidance may be influencing the deposition of calcium to different parts of the exoskeleton in lithodids living in an environment undersaturated with respect to calcium carbonate.     

Long-term feeding a high-fat diet causes histological and parasitological effects on murine schistosomiasis mansoni outcome

This study investigated whether long-term feeding a high-fat diet (HFC) has an effect on schistosomiasis mansoni outcome compared to standard chow diet (SC). Swiss Webster female mice (3 wk old) fed each diet over 5 months, and then were infected with 50 Schistosoma mansoni cercariae. Their nutritional status was assessed by monitoring growth rates twice a week and measuring serum levels of lipoproteins. Mice were euthanised 63 days after infection. Parasitological and liver histological analyses were performed. The levels of TC, HDL-C and LDL-C, fecal and tissue schistosome eggs were statistically different (p<0.05) between groups. Livers from HFC mice showed exudative, exudative/exudative-productive, exudative-productive and productive granulomas, some degree of hepatic steatosis and focal necrosis. Mice fed normal-chow did not present productive granulomas and hepatic steatosis. The morphometric evaluation of hepatic granulomas did not reach statistical significance (p>0.05) between diets assayed. The high-fat diet for long-term produces effects on schistosomiasis mansoni outcome.     

Dynamic reduction with applications to mathematical biology and other areas

In a difference or differential equation one is usually interested in finding solutions having certain properties, either intrinsic properties (e.g. bounded, periodic, almost periodic) or extrinsic properties (e.g. stable, asymptotically stable, globally asymptotically stable). In certain instances it may happen that the dependence of these equations on the state variable is such that one may (1) alter that dependency by replacing part of the state variable by a function from a class having some of the above properties and (2) solve the 'reduced' equation for a solution having the remaining properties and lying in the same class. This then sets up a mapping Τ of the class into itself, thus reducing the original problem to one of finding a fixed point of the mapping. The procedure is applied to obtain a globally asymptotically stable periodic solution for a system of difference equations modeling the interaction of wild and genetically altered mosquitoes in an environment yielding periodic parameters. It is also shown that certain coupled periodic systems of difference equations may be completely decoupled so that the mapping Τ is established by solving a set of scalar equations. Periodic difference equations of extended Ricker type and also rational difference equations with a finite number of delays are also considered by reducing them to equations without delays but with a larger period. Conditions are given guaranteeing the existence and global asymptotic stability of periodic solutions.     

Peroxisome proliferator-activated receptor gamma 2 and acyl-CoA synthetase 5 polymorphisms influence diet response

Peroxisome proliferator-activated receptor gamma (PPARgamma) and its response gene, Acyl CoA synthetase 5 (ACSL5), which has an important role in fatty acid metabolism, may affect weight loss in response to caloric restriction. Therefore, we aimed to determine whether these genes were involved in the interindividual response to dietary treatment. Genotypic/phenotypic comparisons were made between selected obese women from the quintiles losing the most (diet responsive, n = 74) and the quintiles losing the least (diet-resistant, n = 67) weight in the first 6 weeks of a 900-kcal formula diet. Two common PPARgamma single nucleotide polymorphisms, Pro(12)Ala and C1431T, and eight polymorphisms across the ACSL5 gene were selected for single locus and haplotypic association analyses. The PPARgamma Pro(12)Ala single nucleotide polymorphism was associated with diet resistance (odds ratio = 3.48, 95% confidence interval = 1.41 to 8.56, p = 0.03), and the rs2419621, located in the 5'untranslated region of the ACSL5 gene, displayed the strongest association with diet response (odds ratio = 3.45, 95% confidence interval = 1.61 to 7.69, p = 0.001). Skeletal muscle ACSL5 mRNA expression was significantly lower in carriers of the wildtype compared with the variant rs2419621 allele (p = 0.03). Our results suggest a link between PPARgamma2 and ACSL5 genotype and diet responsiveness.     

Low modularity and specialization in a commensalistic epiphyte–phorophyte network in a tropical cloud forest

Species interactions can shape the structure of natural communities. Such sets of interactions have been described as complex ecological networks, an example of which is the commensal network formed by epiphyte–phorophyte interactions. Vascular epiphytes germinate and grow on phorophytes (support trees), assuming a horizontal distribution (among the phorophyte species) and a vertical distribution (from the base of the tree trunk to the crown of phorophytes, i.e., through ecological zones). Here, we investigated the organization of these structural dimensions of the epiphyte–phorophyte network in a Brazilian tropical montane cloud forest. The analyzed network, comprising 66 epiphyte species and 22 phorophyte species, exhibited a nested structure with a low degree of specialization, a typical pattern for epiphyte–phorophyte networks in forests. The network was slightly modular, with 65% of the species common to three modules, and had vertical structure corresponding to the vertical organization of the phorophytes. The size (diameter at breast height) of phorophyte individuals influenced the network structure, possibly due to the increase in habitat area, the time available for colonization by epiphytes, and a greater number of microenvironments. We found that the distribution of the epiphyte species differed between the phorophyte ecological zones, with greater richness in the lower portions and greater abundance in the upper portions of the phorophytes. The results provide relevant guidance for future research on the characteristics and the vertical and horizontal organization of vascular epiphyte and phorophyte networks. Abstract in Portuguese is available with online material.