Integración de los parámetros de remodelado, sincronía y velocidad máxima de vaciado para evaluar la función sistólica del ventrículo izquierdo / Integration of ventricular remodeling, synchrony and filling rate parameters to improve the assessment of left ventricular systolic function

Objetivos El objetivo es estudiar la relación entre los parámetros estructurales, de remodelado, de sincronía y de función sistólica del ventrículo izquierdo (VI) mediante gSPECT. Obtener los valores de corte del VI para el índice de la forma telediastólica (iFTD), el índice de la forma telesistólica (iFTS), el índice de excentricidad (iEX) y la velocidad máxima de vaciado (VMV). Desarrollar un nuevo índice para evaluar diferentes patrones de función sistólica del VI. Material y métodos Analizamos prospectivamente 238 pacientes (edad: 63,4±13 años) estudiados mediante gSPECT de esfuerzo-reposo (grupo-control, n=148; pacientes con infarto de miocardio [IM] previo, n=90). Estudio aprobado por el Comité de Ética del Hospital (PR[AG]168.2010). Resultados En el grupo-control, el índice del volumen telediastólico (iVTD) y el iEX influyeron en el iFTD (r2: 0,52, p<0,001). El iVTD, la VMV, ser varones y el iEX (r2: 0,44; p<0,001) influyeron en el iFTS. El iFTD, iFTS, la fracción de eyección VI (FEVI) y el volumen de eyección sistólica (r2: 0,62; p<0,001) influyeron en el iEX. La FEVI, la frecuencia cardíaca, el ancho de banda (AB) y la desviación estándar influyeron (r2: 0,76; p<0,001) en la VMV. Los valores de corte para iFTD, iFTS, iEX y VMV fueron 0,59, 0,42, 0,87 y −3,3 respectivamente. La VMV, el iFTS y el AB fueron los parámetros mejor relacionados con los pacientes con IM previo (AUC: 0,89), y sumados a la FEVI permitieron obtener distintos patrones de función sistólica (índice PERRS). Conclusiones Los parámetros de remodelado, sincronía y función sistólica del VI deben interpretarse simultáneamente, ya que esto permite obtener distintos patrones de función sistólica del VI (AU)

Introduction and objectives The aim of this study is to assess the relationship between structural, remodeling, synchrony, and systolic left ventricular (LV) function parameters using gated-SPECT myocardial-perfusion-images (gSPECT-MPI). In addition, obtaining the cut-off values for end-diastolic LV-shape-index (EDLVsi), end-systolic LV-shape-index (ESLVsi), ECC (eccentricity-index) and PER, and developing a new index to evaluate different patterns of the LV systolic function. Methods The study was approved by the Hospital's Ethical-Committee (PR[AG]168.2010), and all patients gave their informed consent. We analyzed prospectively 238 patients (age 63.4±13 years) who underwent stress-rest gSPECT-MPI (control-group, n=148; patients with previous myocardial infarction [MI], n=90). Results In the control group, with regard to remodeling parameters: the end-diastolic-volume-index (EDV) and the ECC were the parameters that influenced the EDLVsi (r2: 0.52, P<.001). EDV, PER, men, and the ECC were the parameters (r2: 0.44; P<.001) which influenced the ESLVsi. EDLVsi, ESLVsi, LVEF and the stroke-volume were the parameters (r2: 0.62; P<.001) which influenced the ECC. With regards to PER: LVEF, heart-rate, bandwidth, and the standard-deviation were the influencing parameters (r2: 0.76; P<.001). The cut-off values for EDLVsi, ESLVsi, ECC, and PER were 0.59, 0.42, 0.87, and 3.3, respectively. The PER, the ESLVsi and the bandwidth were the parameters related to patients with previous MI (AUC: 0.89); and they allow the assessment of different patterns of systolic function (PERRS-index: Peak-Emptying-Rate, left ventricular-Remodeling and Synchrony). Conclusions The remodeling, synchrony and the systolic function parameters of the LV should be interpreted together (PERRS-index). In this way, we obtain different patterns of LV systolic function (AU)

Integration of ventricular remodeling, synchrony and filling rate parameters to improve the assessment of left ventricular systolic function.

INTRODUCTION AND OBJECTIVES: The aim of this study is to assess the relationship between structural, remodeling, synchrony, and systolic left ventricular (LV) function parameters using gated-SPECT myocardial-perfusion-images (gSPECT-MPI). In addition, obtaining the cut-off values for end-diastolic LV-shape-index (EDLVsi), end-systolic LV-shape-index (ESLVsi), ECC (eccentricity-index) and PER, and developing a new index to evaluate different patterns of the LV systolic function. METHODS: The study was approved by the Hospital's Ethical-Committee (PR[AG]168.2010), and all patients gave their informed consent. We analyzed prospectively 238 patients (age 63.4 ±â€¯13 years) who underwent stress-rest gSPECT-MPI (control-group, n = 148; patients with previous myocardial infarction [MI], n = 90). RESULTS: In the control group, with regard to remodeling parameters: the end-diastolic-volume-index (EDV) and the ECC were the parameters that influenced the EDLVsi (r2: 0.52, p < 0.001). EDV, PER, men, and the ECC were the parameters (r2: 0.44; p < 0.001) which influenced the ESLVsi. EDLVsi, ESLVsi, LVEF and the stroke-volume were the parameters (r2: 0.62; p < 0.001) which influenced the ECC. With regards to PER: LVEF, heart-rate, bandwidth, and the standard-deviation were the influencing parameters (r2: 0.76; p < 0.001). The cut-off values for EDLVsi, ESLVsi, ECC, and PER were 0.59, 0.42, 0.87, and 3.3, respectively. The PER, the ESLVsi and the bandwidth were the parameters related to patients with previous MI (AUC: 0.89); and they allow the assessment of different patterns of systolic function (PERRS-index: peak-emptying-rate, left ventricular-remodeling and synchrony). CONCLUSIONS: The remodeling, synchrony and the systolic function parameters of the LV should be interpreted together (PERRS-index). In this way, we obtain different patterns of LV systolic function.

ScipionTomo: Towards cryo-electron tomography software integration, reproducibility, and validation.

Image processing in cryogenic electron tomography (cryoET) is currently at a similar state as Single Particle Analysis (SPA) in cryogenic electron microscopy (cryoEM) was a few years ago. Its data processing workflows are far from being well defined and the user experience is still not smooth. Moreover, file formats of different software packages and their associated metadata are not standardized, mainly since different packages are developed by different groups, focusing on different steps of the data processing pipeline. The Scipion framework, originally developed for SPA (de la Rosa-Trevín et al., 2016), has a generic python workflow engine that gives it the versatility to be extended to other fields, as demonstrated for model building (Martínez et al., 2020). In this article, we provide an extension of Scipion based on a set of tomography plugins (referred to as ScipionTomo hereafter), with a similar purpose: to allow users to be focused on the data processing and analysis instead of having to deal with multiple software installation issues and the inconvenience of switching from one to another, converting metadata files, managing possible incompatibilities, scripting (writing a simple program in a language that the computer must convert to machine language each time the program is run), etcetera. Additionally, having all the software available in an integrated platform allows comparing the results of different algorithms trying to solve the same problem. In this way, the commonalities and differences between estimated parameters shed light on which results can be more trusted than others. ScipionTomo is developed by a collaborative multidisciplinary team composed of Scipion team engineers, structural biologists, and in some cases, the developers whose software packages have been integrated. It is open to anyone in the field willing to contribute to this project. The result is a framework extension that combines the acquired knowledge of Scipion developers in close collaboration with third-party developers, and the on-demand design of functionalities requested by beta testers applying this solution to actual biological problems.

On bias, variance, overfitting, gold standard and consensus in single-particle analysis by cryo-electron microscopy.

Cryo-electron microscopy (cryoEM) has become a well established technique to elucidate the 3D structures of biological macromolecules. Projection images from thousands of macromolecules that are assumed to be structurally identical are combined into a single 3D map representing the Coulomb potential of the macromolecule under study. This article discusses possible caveats along the image-processing path and how to avoid them to obtain a reliable 3D structure. Some of these problems are very well known in the community. These may be referred to as sample-related (such as specimen denaturation at interfaces or non-uniform projection geometry leading to underrepresented projection directions). The rest are related to the algorithms used. While some have been discussed in depth in the literature, such as the use of an incorrect initial volume, others have received much less attention. However, they are fundamental in any data-analysis approach. Chiefly among them, instabilities in estimating many of the key parameters that are required for a correct 3D reconstruction that occur all along the processing workflow are referred to, which may significantly affect the reliability of the whole process. In the field, the term overfitting has been coined to refer to some particular kinds of artifacts. It is argued that overfitting is a statistical bias in key parameter-estimation steps in the 3D reconstruction process, including intrinsic algorithmic bias. It is also shown that common tools (Fourier shell correlation) and strategies (gold standard) that are normally used to detect or prevent overfitting do not fully protect against it. Alternatively, it is proposed that detecting the bias that leads to overfitting is much easier when addressed at the level of parameter estimation, rather than detecting it once the particle images have been combined into a 3D map. Comparing the results from multiple algorithms (or at least, independent executions of the same algorithm) can detect parameter bias. These multiple executions could then be averaged to give a lower variance estimate of the underlying parameters.

Correlative 3D cryo X-ray imaging reveals intracellular location and effect of designed antifibrotic protein-nanomaterial hybrids.

Revealing the intracellular location of novel therapeutic agents is paramount for the understanding of their effect at the cell ultrastructure level. Here, we apply a novel correlative cryo 3D imaging approach to determine the intracellular fate of a designed protein-nanomaterial hybrid with antifibrotic properties that shows great promise in mitigating myocardial fibrosis. Cryo 3D structured illumination microscopy (cryo-3D-SIM) pinpoints the location and cryo soft X-ray tomography (cryo-SXT) reveals the ultrastructural environment and subcellular localization of this nanomaterial with spatial correlation accuracy down to 70 nm in whole cells. This novel high resolution 3D cryo correlative approach unambiguously locates the nanomaterial after overnight treatment within multivesicular bodies which have been associated with endosomal trafficking events by confocal microscopy. Moreover, this approach allows assessing the cellular response towards the treatment by evaluating the morphological changes induced. This is especially relevant for the future usage of nanoformulations in clinical practices. This correlative super-resolution and X-ray imaging strategy joins high specificity, by the use of fluorescence, with high spatial resolution at 30 nm (half pitch) provided by cryo-SXT in whole cells, without the need of staining or fixation, and can be of particular benefit to locate specific molecules in the native cellular environment in bio-nanomedicine.

Algorithmic robustness to preferred orientations in single particle analysis by CryoEM.

The presence of preferred orientations in single particle analysis (SPA) by cryo-Electron Microscopy (cryoEM) is currently one of the hurdles preventing many structural analyses from yielding high-resolution structures. Although the existence of preferred orientations is mostly related to the grid preparation, in this technical note, we show that some image processing algorithms used for angular assignment and three-dimensional (3D) reconstruction are more robust than others to these detrimental conditions. We exemplify this argument with three different data sets in which the presence of preferred orientations hindered achieving a 3D reconstruction without artifacts or, even worse, a 3D reconstruction could never be achieved.

BDNF levels and nigrostriatal degeneration in "drug naïve" Parkinson's disease patients. An "in vivo" study using I-123-FP-CIT SPECT.

INTRODUCTION: Parkinson's Disease (PD) is a common neurodegenerative disorder, characterized by a progressive loss of dopaminergic neurons and whose cause remains unclear. Brain-Derived Neurotrophic factor (BDNF) is a protein involved in dopaminergic cells survival. Previous studies have shown decreased serum BDNF levels in PD patients. AIM AND OBJECTIVES: The aim of the study was to evaluate serum BDNF levels in a group of recently diagnosed non-medicated PD patients and its relationship with the nigrostriatal system degeneration using I-123-FP-CIT. METHODS: 30 recently diagnosed, unmedicated PD patients were included in this study. Serum BDNF levels were measured twice using a sandwich enzyme linked immunoabsorbent assay and compared with levels of 27 unrelated Caucasian healthy adults. A I-123-FP-CIT SPECT was performed in all PD Patients in order to assess the association between serum BDNF levels and I-123-FP CIT uptake in several brain areas using a volumetric semi-automatic method. RESULTS: PD patients showed lower serum BDNF levels (Median = 49.61, IQ range: 43.55 to 61.82) than the controls (Median = 68.82, IQ range: 51.87 to 88.14) (U = 211.00, z = -3.10, p = 0.002). BDNF levels in PD patients correlated with both caudate (Spearman r = 0.58, p = 0.001 for ispilateral and r 0.55, p = 0.002 for contralateral) and putamen (Spearman r = 0.68, p < 0.001 for ipsilateral and r = 0.80, p < 0.001 for contralateral) I-123-FP-CIT uptake ratios. CONCLUSIONS: Serum BDNF levels were lower in recently diagnosed, untreated PD patients compared to controls. These lower levels were significantly correlated with the I-123-FP-CIT uptake ratios.

Integration of Cryo-EM Model Building Software in Scipion.

Advances in cryo-electron microscopy (cryo-EM) have made it possible to obtain structures of large biological macromolecules at near-atomic resolution. This "resolution revolution" has encouraged the use and development of modeling tools able to produce high-quality atomic models from cryo-EM density maps. Unfortunately, many practical problems appear when combining different packages in the same processing workflow, which make difficult the use of these tools by non-experts and, therefore, reduce their utility. We present here a major extension of the image processing framework Scipion that provides inter-package integration in the model building area and full tracking of the complete workflow, from image processing to structure validation.

The cellular landscape by cryo soft X-ray tomography.

Imaging techniques in structural cell biology are indispensable to understand cell organization and machinery. In this frame, cryo soft X-ray tomography (cryo-SXT), a synchrotron-based imaging technique, is used to analyze the ultrastructure of intact, cryo-preserved cells at nanometric spatial resolution bridging electron microscopy and visible light fluorescence. With their unique interaction with matter and high penetration depth, X-rays are a very useful and complementary source to obtain both high-resolution and quantitative information. In this review, we are elaborating a typical cryo correlative workflow at the Mistral Beamline at the Alba Synchrotron (Spain) with the goal of providing a cartographic description of the cell by cryo-SXT that illustrates the possibilities this technique brings for specific localization of cellular features, organelle organization, and particular events in specific structural cell biology research.

Detección de tejido paratiroideo hiperfuncionante mediante PET/TC con 18F-fluorocolina / Detection of hyperfunctioning parathyroid tissue by 18F-Fluorocholine PET/CT

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Pollinator Preferences for Floral Volatiles Emitted by Dimorphic Anthers of a Buzz-Pollinated Herb.

Floral scents attract pollinators to plant rewards; in nectarless flowers, pollen grains are the only reward. Thus, pollen not only fertilizes ovules, but also feeds pollinators. This dilemma is resolved by specialization of anthers (i.e., heteranthery): feeding anthers that feed pollinators and pollinating anthers for fertilization. We hypothesized that the chemical composition of floral volatiles differs between the two types of anther and influences pollination preference for feeding anthers. We used Solanum rostratum as a study model because its heterantherous flowers produce a floral scent that suggests a close association with their pollinators. The main aim of this study was to determine the chemical composition of the two types of anther and to investigate how they influence foraging behaviour of pollinators. To characterize this composition, we used solid phase microextraction and hexane extraction followed by gas chromatography-mass spectrometry. We registered 12 volatile compounds in S. rostratum floral extracts, mainly aromatic and sesquiterpene compounds. The proportion of these compounds differed between feeding and pollinating anthers. Some of these compounds were probably emitted by osmophores located in both anther types. Also, we used electroantennography to investigate Melipona solani antennal response to floral volatiles. The M. solani antennae are receptive to the highest floral extract dose tested. Finally, we conducted two behavioural bioassays to test bee attraction for each type of floral extract: a) multiple-choice in a feeding arena using M. solani and b) Y-olfactometer bioassay using Bombus impatiens. Both bee species preferred feeding anthers in bioassays. In conclusion, heteranthery involves chemical differentiation (i.e., proportion of volatiles compounds) in anther specialization that influences bee preference for feeding anthers over pollinating anthers.

Effect of marine ambient in the production of pollutants from the pyrolysis and combustion of a mixture of plastic materials.

A mixture of polyethylene (PE), polyethylene-terephtalate (PET), polypropylene (PP) and Nylon was submerged in marine water during 12 moths. The chlorine content of these plastics was measured through the passing time. Thermobalance was used to look for differences in the thermal decomposition of the plastics during in that time interval. Degradation of PET, PP and Nylon produced changes in the weight loss curve, but behaviour of PE is confusing. Pyrolysis and combustion at 850 °C was finally performed to get knowledge of the possible differences in the emission of main gases, volatiles and semivolatiles including polycyclic aromatic hydrocarbons (PAHs), polychlorinated benzenes (ClBzs), polychlorinated phenols (ClPhs), polybrominated phenols (BrPhs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Results show that the emission of chlorinated species is somewhat not affected by the chlorine content of the plastics mix. The production of PCBs and PCDD/Fs was very low, under 4 pg WHO-TEQ/g.

Volatile and semivolatile emissions from the pyrolysis of almond shell loaded with heavy metals.

Heavy metal-loaded almond shell was subjected to pyrolysis to understand the effect of the presence of different heavy metals on its thermal degradation. Pyrolysis behavior of native and metal-loaded samples was studied by thermogravimetric analysis. Similar shapes of thermogravimetric curves indicate that the presence of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and lead (Pb) did not change the main degradation pathways of almond shell. However, the temperature at which the decomposition in each stage takes place at a higher rate and char yield was considerably modified by the presence of Cr and Ni. Then, pyrolysis tests of the almond shell samples were performed in a moving tubular reactor at 700°C. Gases and volatile organic compounds were collected using Tedlar bags and semivolatile organic compounds were collected using a resin as adsorbent. Significant changes were obtained in the composition of the gaseous fraction as a result of the metal impregnation. The main changes in the composition of the gas were observed for Ni-loaded sample, which presented the highest H2 and CO yields. Also, the yields of most of the light hydrocarbons decrease in the presence of metal, while the rest remain quite similar. The total PAH yields reached 103µg/g for nickel-loaded sample (NiAS), 164µg/g for copper-loaded sample (CuAS), 172µg/g for lead-loaded sample (PbAS), 245µg/g for native sample (AS), 248µg/g for cadmium-loaded sample (CdAS) and 283µg/g for chromium-loaded sample (CrAS). Nickel is the most effective in the higher aromatic tar reduction, followed by Cu and Pb, whereas the presence of Cd does not affect the total emissions of PAHs. Finally, the carcinogenic potency of the samples was calculated. Native sample and the sample loaded with Cr presented slightly higher values associated to the presence of small amounts of benzo(a)pyrene.

Pollutant content in marine debris and characterization by thermal decomposition.

Marine debris (MDs) produces a wide variety of negative environmental, economic, safety, health and cultural impacts. Most marine litter has a very low decomposition rate (plastics), leading to a gradual accumulation in the coastal and marine environment. Characterization of the MDs has been done in terms of their pollutant content: PAHs, ClBzs, ClPhs, BrPhs, PCDD/Fs and PCBs. The results show that MDs is not a very contaminated waste. Also, thermal decomposition of MDs materials has been studied in a thermobalance at different atmospheres and heating rates. Below 400-500K, the atmosphere does not affect the thermal degradation of the mentioned waste. However, at temperatures between 500 and 800K the presence of oxygen accelerates the decomposition. Also, a kinetic model is proposed for the combustion of the MDs, and the decomposition is compared with that of their main constituents, i.e., polyethylene (PE), polystyrene (PS), polypropylene (PP), nylon and polyethylene-terephthalate (PET).

Energy potential and alternative usages of biogas and sludge from UASB reactors: case study of the Laboreaux wastewater treatment plant.

This work assessed the energy potential and alternative usages of biogas and sludge generated in upflow anaerobic sludge blanket reactors at the Laboreaux sewage treatment plant (STP), Brazil. Two scenarios were considered: (i) priority use of biogas for the thermal drying of dehydrated sludge and the use of the excess biogas for electricity generation in an ICE (internal combustion engine); and (ii) priority use of biogas for electricity generation and the use of the heat of the engine exhaust gases for the thermal drying of the sludge. Scenario 1 showed that the electricity generated is able to supply 22.2% of the STP power demand, but the thermal drying process enables a greater reduction or even elimination of the final volume of sludge to be disposed. In Scenario 2, the electricity generated is able to supply 57.6% of the STP power demand; however, the heat in the exhaust gases is not enough to dry the total amount of dehydrated sludge.

The effect of carbon nanofillers on the performance of electromechanical polyaniline-based composite actuators.

Different types of crystalline carbon nanomaterials were used to reinforce polyaniline for use in electromechanical bilayer bending actuators. The objective is to analyze how the different graphitic structures of the nanocarbons affect and improve the in situ polymerized polyaniline composites and their subsequent actuator behavior. The nanocarbons investigated were multiwalled carbon nanotubes, nitrogen-doped carbon nanotubes, helical-ribbon carbon nanofibers and graphene oxide, each one presenting different shape and structural characteristics. Films of nanocarbon-PAni composite were tested in a liquid electrolyte cell system. Experimental design was used to select the type of nanocarbon filler and composite loadings, and yielded a good balance of electromechanical properties. Raman spectroscopy suggests good interaction between PAni and the nanocarbon fillers. Electron microscopy showed that graphene oxide dispersed the best, followed by multiwall carbon nanotubes, while nitrogen-doped nanotube composites showed dispersion problems and thus poor performance. Multiwall carbon nanotube composite actuators showed the best performance based on the combination of bending angle, bending velocity and maximum working cycles, while graphene oxide attained similarly good performance due to its best dispersion. This parallel testing of a broad set of nanocarbon fillers on PAni-composite actuators is unprecedented to the best of our knowledge and shows that the type and properties of the carbon nanomaterial are critical to the performance of electromechanical devices with other conditions remaining equal.