Structure-activity relationship study of cationic carbosilane dendritic systems as antibacterial agents

This work focuses on the antibacterial activity against Gram-positive Staphylococcus aureus and Gramnegative Escherichia coli and the hemolytic properties of two types of ammonium cationic carbosilane systems: dendrimers and dendrons. The effects of: i) the generation, ii) the type of peripheral groups near the cationic charges (a SiMe2 moiety or a S atom depending on the synthetic procedure, hydrosilylation or thiol-ene addition, respectively), iii) the core of dendrimers (polyphenoxo vs. Si atom) and iv) the focal point of dendrons (-N3, -NH2, -OH) have been assessed. The structure-activity relationship analysis indicates the importance of an adequate balance between the hydrophilic and lipophilic fragments of these molecules to reach the best antibacterial activity. Regarding hemolysis, lowest toxicity values were registered for dendritic systems with a sulfur atom close to the surface and, in the particular case of dendrons, for those with a hydroxyl focal point. One dendrimer and one dendron, both bearing a sulfur atom close to the surface, scored best in the activity-toxicity relationship analysis and were chosen for resistance assays. No changes in the inhibitory and bactericidal capacity in the case of the dendron and only a slight increase of these values for the dendrimer were observed after 15 subculture cycles. Furthermore, these two compounds stayed active towards different strains of resistant bacteria and avoid formation of biofilm at concentrations over the minimum inhibitory concentration (MIC).Ministerio de Economía y Empres

Nonreferral of possible soft tissue sarcomas in adults: a dangerous omission in policy

Introduction. The aim of this study is to compare outcomes in three groups of STS patients treated in our specialist centre: patients referred immediately after an inadequate initial treatment, patients referred after a local recurrence, and patients referred directly, prior to any treatment. Patients and methods. We reviewed all our nonmetastatic extremity-STS patients with a minimum follow-up of 2 years. We compared three patient groups: those referred directly to our centre (group A), those referred after an inadequate initial excision (group B), and patients with local recurrence (group C). Results. The study included 174 patients. Disease-free survival was 73%, 76%, and 28% in groups A, B, and C, respectively (P < .001). Depth, size, and histologic grade influenced the outcome in groups A and B, but not in C. Conclusion. Initial wide surgical treatment is the main factor that determines local control, being even more important than the known intrinsic prognostic factors of tumour size, depth, and histologic grade. The influence on outcome of initial wide local excision (WLE), which is made possible by referral to a specialist centre, is paramount

Familial hypercholesterolaemia: A study of 36 cases with a phenotype of homozygous familiar hypercholesterolaemia

La hipercolesterolemia familiar homocigótica (HFHo) se caracteriza por niveles muy elevados de cLDL y por enfermedad aterosclerótica temprana. Aunque la frecuencia es baja (1/300.000), las complicaciones son muy severas y pueden ser evitadas. Encontrar y tratar esta población de manera temprana podría reducir la mortalidad. Se describen 36 casos en Colombia, en donde se calcula que haya entre 160 y 200 casos. Resultados Un total de 36 pacientes con fenotipo sugestivo de HFHo fueron identificados y tratados en un período de observación de cuatro años. La media de edad fue 27 años (24 mujeres). 34 pacientes tuvieron un puntaje según la Red de Clínicas de Lípidos de Holanda (RCLH) mayor de 8 (diagnóstico definitivo) y los restantes 2 tenían puntaje equivalente a diagnóstico probable. Un cuarto de los casos procedían de la costa norte colombiana. En las pruebas genéticas, 14 fueron homocigóticos verdaderos para mutación del gen que codifica para el receptor de LDL (LDLR), 12 heterocigóticos compuestos, 2 heterocigóticos dobles y uno autosómico recesivo (LDLRAP1); 5 pacientes fueron heterocigóticos simples (LDLR) y 2 pacientes no autorizaron la prueba. En los homocigóticos verdaderos, la variante más frecuente encontrada fue la c.11G>A. 14 pacientes cursaron con enfermedad coronaria, 9 con estenosis carotídea, 8 con estenosis aórtica y 2 tuvieron ataques cerebrovasculares (ACV). 34 pacientes recibían estatinas (24 rosuvastatina), 30 recibían ezetimibe, 2 recibían evolocumab y 20 recibían lomitapide (dosis promedio 12,7mg). Ninguno recibió aféresis de cLDL. Los medicamentos, en general, fueron bien tolerados y la reducción promedio de cLDL con la terapia fue de 533,7mg/dl a 245,1mg/dl (54%). Conclusiones Todos los pacientes recibieron tratamiento hipolipemiante y se encontraron alteraciones genéticas diagnósticas en todos aquellos que autorizaron el examen. Los niveles elevados de cLDL conllevan tanto riesgo que el tratamiento debe establecerse aún sin conocer el diagnóstico genético.Homozygous familial hypercholesterolemia (HoFH) is characterized for very high levels of cLDL and early cardiovascular disease. Although incidence is low (1/300 000), complications are very severe and can be avoided. Finding and treating this population promptly could reduce mortality. We describe 36 cases in Colombia, where 160 to 200 cases are expected. Results 36 patients with phenotype of HoHF were identified and treated in a follow-up of 4 years. The mean age was 27 years (24 women). 34 of them had at least 8 points in the FH Dutch Lipid Clinic Criteria (definitive diagnosis) and two had probable diagnosis. A quarter of the cases came from the Colombian North Coast. In molecular tests, 14 were true homozygous for LDLR, 12 were compound heterozygous for LDLR, 2 double heterozygous and one was autosomal recessive; 5 were heterozygous and 2 patients did not authorized genetic test. In true homozygous subjects, the most frequent variant was c.11G>A. 14 patients had coronary disease, 9 carotid stenosis, 8 aortic stenosis and 2 had stroke. 34 patients were on statins (25 rosuvastatin), 30 were receiving ezetimibe, 2 were receiving a PSCK9 inhibitor (evolocumab) and 20 were on lomitapide with mean doses of 12.7mg. None received lipoprotein apheresis. Medications were very well tolerated. Changes in cLDL after therapy was from 533.7 mg/dL to 245 mg/dL, (54%). Conclusions Treatment was started in all patients. We found genetic mutations in all patients with genetic tests. The high levels of cLDL mean such a high risk that treatment must be started promptly, even without a genetic test

Evolutionary Convergence and Nitrogen Metabolism in Blattabacterium strain Bge, Primary Endosymbiont of the Cockroach Blattella germanica

Bacterial endosymbionts of insects play a central role in upgrading the diet of their hosts. In certain cases, such as aphids and tsetse flies, endosymbionts complement the metabolic capacity of hosts living on nutrient-deficient diets, while the bacteria harbored by omnivorous carpenter ants are involved in nitrogen recycling. In this study, we describe the genome sequence and inferred metabolism of Blattabacterium strain Bge, the primary Flavobacteria endosymbiont of the omnivorous German cockroach Blattella germanica. Through comparative genomics with other insect endosymbionts and free-living Flavobacteria we reveal that Blattabacterium strain Bge shares the same distribution of functional gene categories only with Blochmannia strains, the primary Gamma-Proteobacteria endosymbiont of carpenter ants. This is a remarkable example of evolutionary convergence during the symbiotic process, involving very distant phylogenetic bacterial taxa within hosts feeding on similar diets. Despite this similarity, different nitrogen economy strategies have emerged in each case. Both bacterial endosymbionts code for urease but display different metabolic functions: Blochmannia strains produce ammonia from dietary urea and then use it as a source of nitrogen, whereas Blattabacterium strain Bge codes for the complete urea cycle that, in combination with urease, produces ammonia as an end product. Not only does the cockroach endosymbiont play an essential role in nutrient supply to the host, but also in the catabolic use of amino acids and nitrogen excretion, as strongly suggested by the stoichiometric analysis of the inferred metabolic network. Here, we explain the metabolic reasons underlying the enigmatic return of cockroaches to the ancestral ammonotelic state

Why is the Winner the Best?

International benchmarking competitions have become fundamental for the comparative performance assessment of image analysis methods. However, little attention has been given to investigating what can be learnt from these competitions. Do they really generate scientific progress? What are common and successful participation strategies? What makes a solution superior to a competing method? To address this gap in the literature, we performed a multicenter study with all 80 competitions that were conducted in the scope of IEEE ISBI 2021 and MICCAI 2021. Statistical analyses performed based on comprehensive descriptions of the submitted algorithms linked to their rank as well as the underlying participation strategies revealed common characteristics of winning solutions. These typically include the use of multi-task learning (63%) and/or multi-stage pipelines (61%), and a focus on augmentation (100%), image preprocessing (97%), data curation (79%), and post-processing (66%). The “typical” lead of a winning team is a computer scientist with a doctoral degree, five years of experience in biomedical image analysis, and four years of experience in deep learning. Two core general development strategies stood out for highly-ranked teams: the reflection of the metrics in the method design and the focus on analyzing and handling failure cases. According to the organizers, 43% of the winning algorithms exceeded the state of the art but only 11% completely solved the respective domain problem. The insights of our study could help researchers (1) improve algorithm development strategies when approaching new problems, and (2) focus on open research questions revealed by this work

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

Basin-wide variations in Amazon forest structure and function are mediated by both soils and climate

Forest structure and dynamics vary across the Amazon Basin in an east-west gradient coincident with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. Soil samples were collected in a total of 59 different forest plots across the Amazon Basin and analysed for exchangeable cations, carbon, nitrogen and pH, with several phosphorus fractions of likely different plant availability also quantified. Physical properties were additionally examined and an index of soil physical quality developed. Bivariate relationships of soil and climatic properties with above-ground wood productivity, stand-level tree turnover rates, above-ground wood biomass and wood density were first examined with multivariate regression models then applied. Both forms of analysis were undertaken with and without considerations regarding the underlying spatial structure of the dataset. Despite the presence of autocorrelated spatial structures complicating many analyses, forest structure and dynamics were found to be strongly and quantitatively related to edaphic as well as climatic conditions. Basin-wide differences in stand-level turnover rates are mostly influenced by soil physical properties with variations in rates of coarse wood production mostly related to soil phosphorus status. Total soil P was a better predictor of wood production rates than any of the fractionated organic- or inorganic-P pools. This suggests that it is not only the immediately available P forms, but probably the entire soil phosphorus pool that is interacting with forest growth on longer timescales. A role for soil potassium in modulating Amazon forest dynamics through its effects on stand-level wood density was also detected. Taking this into account, otherwise enigmatic variations in stand-level biomass across the Basin were then accounted for through the interacting effects of soil physical and chemical properties with climate. A hypothesis of self-maintaining forest dynamic feedback mechanisms initiated by edaphic conditions is proposed. It is further suggested that this is a major factor determining endogenous disturbance levels, species composition, and forest productivity across the Amazon Basin. © 2012 Author(s). CC Attribution 3.0 License

Differential clinical characteristics and prognosis of intraventricular conduction defects in patients with chronic heart failure

Intraventricular conduction defects (IVCDs) can impair prognosis of heart failure (HF), but their specific impact is not well established. This study aimed to analyse the clinical profile and outcomes of HF patients with LBBB, right bundle branch block (RBBB), left anterior fascicular block (LAFB), and no IVCDs. Clinical variables and outcomes after a median follow-up of 21 months were analysed in 1762 patients with chronic HF and LBBB (n = 532), RBBB (n = 134), LAFB (n = 154), and no IVCDs (n = 942). LBBB was associated with more marked LV dilation, depressed LVEF, and mitral valve regurgitation. Patients with RBBB presented overt signs of congestive HF and depressed right ventricular motion. The LAFB group presented intermediate clinical characteristics, and patients with no IVCDs were more often women with less enlarged left ventricles and less depressed LVEF. Death occurred in 332 patients (interannual mortality = 10.8%): cardiovascular in 257, extravascular in 61, and of unknown origin in 14 patients. Cardiac death occurred in 230 (pump failure in 171 and sudden death in 59). An adjusted Cox model showed higher risk of cardiac death and pump failure death in the LBBB and RBBB than in the LAFB and the no IVCD groups. LBBB and RBBB are associated with different clinical profiles and both are independent predictors of increased risk of cardiac death in patients with HF. A more favourable prognosis was observed in patients with LAFB and in those free of IVCDs. Further research in HF patients with RBBB is warranted