Multitarget and suspect-screening of antimicrobials in vegetables samples: Uptake experiments and identification of transformation products.

This work provided an accurate analytical method to perform a multitarget analysis of a variety of antimicrobials (AMs) including sulfonamides, tetracyclines, macrolides, fluoroquinolones and quinolones, one imidazole and one nitroimidazole, one triazole, one diaminopyridine and one derivative of Penicillium stoloniferum in vegetables. The analysis is performed using liquid-chromatography coupled to a low-resolution triple quadrupole mass spectrometer (UHPLC-MS/MS) to detect the target analytesor coupled to a high-resolution q-Orbitrap (HRMS) to monitor the formed transformation products (TPs). Both instruments were compared in terms of limits of quantification and matrix effect at the detection. The method was applied to determine the presence of AMs in organic and non-organic vegetables, where sulfadiazine and mycophenolic acid were detected. On the other hand, the transference of four AMs (trimethoprim, sulfamethazine, enrofloxacin, and chlortetracycline) from soils to lettuces was evaluated through controlled uptake experiments. The choice of AMs was based on the classification into different families, and on the fact that those AM families are the most frequently detected in the environment. In this case, each of the AMs with which the soils were contaminated were found in the exposed lettuces. Moreover, in both studies, specific TPs of the AMs were identified, posing the necessity of assessing their effects in relation to food and human safety.

Antimicrobials in Eisenia fetida earthworms: A comprehensive study from method development to the assessment of uptake and degradation.

In this work, an accurate analytical method was developed for the simultaneous analysis of twenty-seven antimicrobials (AMs) in earthworms using liquid chromatography coupled to a triple quadrupole mass spectrometry detector (UHPLC-MS/MS). Adequate apparent recoveries (80-120 %) and limits of quantification (LOQ) (1 µg·kg-1 - 10 µg·kg-1) were obtained, with the exception of norfloxacin (34 µg·kg-1). The method was applied to evaluate the accumulation of sulfamethazine (SMZ) and tetracycline (TC) in earthworms after performing OECD-207 toxicity test, in which Eisenia fetida (E. fetida) organisms were exposed to soils spiked with 10 mg·kg-1, 100 mg·kg-1 or 1000 mg·kg-1 of SMZ and TC, individually. The results confirmed the bioaccumulation of both AMs in the organisms, showing a greater tendency to accumulate SMZ since higher bioconcentration factor values were obtained for this compound at the exposure concentrations tested. In addition, the degradation of both AMs in both matrices, soils and earthworms was studied using liquid chromatography coupled to a q-Orbitrap high resolution mass spectrometry detector. Thirteen transformation products (TPs) were successfully identified, eight of them being identified for the first time in soil/earthworm (such as 4-Amino-3-chloro-n-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide or 4-(dimethylamino)-1,11,12a-trihydroxy-6,6-dimethyl-3,7,10,12-tetraoxo-3,4,4a,5,5a,6,7,10,12,12a-decahydrotetracene-2-carboxamide, among others) and their formation/degradation trend over time was also studied. Regarding the biological effects, only SMZ caused changes in earthworm growth, evidenced by weight loss in earthworms exposed to concentrations of 100 mg·kg-1 and 1000 mg·kg-1. Riboflavin decreased at all concentrations of SMZ, as well as at the highest concentration of TC. This indicates that these antibiotics can potentially alter the immune system of E. fetida. This research represents a significant advance in improving our knowledge about the contamination of soil by AM over time. It investigates the various ways in which earthworms are exposed to AMs, either by skin contact or ingestion. Furthermore, it explores how these substances accumulate in earthworms, the processes by which earthworms break them down or metabolise them, as well as the resulting TPs. Finally, it examines the potential effects of these substances on the environment.

Multitarget and suspect screening of antimicrobials in soil and manure by means of QuEChERS - liquid chromatography tandem mass spectrometry.

The present work aimed to develop an accurate analytical method for the simultaneous analysis of twenty-four antimicrobials in soil:compost and animal manure samples by means of ultra-high performance liquid chromatography coupled to a triple-quadrupole mass spectrometer (UHPLC-QqQ). For this purpose, the effectiveness of two extraction techniques (i.e. focused ultrasound solid-liquid extraction (FUSLE) and QuEChERS (quick, easy, cheap, effective, rugged and safe)) was evaluated, and the clean-up step using solid-phase extraction (SPE) was also thoroughly studied. The method was successfully validated at 10 µg·kg-1, 25 µg·kg-1, and 50 µg·kg-1 showing adequate trueness (70-130%) and repeatability (RSD < 30%), with few exceptions. Procedural limits of quantification (LOQPRO) were determined for soil:compost (0.45 to 7.50 µg·kg-1) and manure (0.31 to 5.53 µg·kg-1) samples. Pefloxacin could not be validated at the lowest level since LOQPRO ≥ 10 µg·kg-1. Sulfamethazine (7.9 ± 0.8 µg·kg-1), danofloxacin (27.1 ± 1.4 µg·kg-1) and trimethoprim (4.9 ± 0.5 µg·kg-1) were detected in soil samples; and tetracycline (56.8 ± 2.8 µg·kg-1), among other antimicrobials, in the plants grown on the surface of the studied soil samples. Similarly, sulfonamides (SAs), tetracyclines (TCs) and fluoroquinolones (FQs) were detected in sheep manure in a range of 1.7 ± 0.3 to 93.3 ± 6.8 µg·kg-1. Soil and manure samples were also analysed through UHPLC coupled to a high-resolution mass-spectrometer (UHPLC-qOrbitrap) in order to extend the multitarget method to suspect screening of more than 22,281 suspects. A specific transformation product (TP) of sulfamethazine (formyl-sulfamethazine) was annotated at 2a level in manure samples, among others. This work contributes to the efforts that have been made in the last decade to develop analytical methods that allow multitarget analysis of a wide variety of antimicrobials, including TPs, which is a complex task due to the diverse physicochemical properties of the antimicrobials.

Comparison of conventional and dispersive solid phase extraction clean-up approaches for the simultaneous analysis of tetracyclines and sulfonamides in a variety of fresh vegetables.

The extensive use of antibiotics in agriculture has led to the occurrence of residual drugs in different vegetables frequently consumed by humans. This could pose a potential threat to human health, not only because of the possible effects after ingestion but also because the transmission of antibiotic-resistant genes could occur. In this work, two accurate sample preparation procedures were developed and validated for the simultaneous analysis of sulfonamides (SAs) and tetracyclines (TCs) in four of the most widely consumed vegetables (lettuce, onion, tomato, and carrot) in Europe. The evaluated protocols were based on QuECHERS for extraction and subsequent clean-up by SPE (solid phase extraction) or dispersive SPE. Parameters affecting both extraction and clean-up were carefully evaluated and selected for accuracy of results and minimal matrix effect. Overall, apparent recoveries were above 70% for most of the target analytes with both analytical procedures, and adequate precision (RSD<30%) was obtained for all the matrices. The procedural limits of quantification (LOQPRO) values for SPE clean-up remained below 4.4 µg kg-1 for TCs in all vegetables except for chlortetracycline (CTC) in lettuce (11.3 µg kg-1) and 3.0 µg kg-1 for SAs, with the exception of sulfadiazine (SDZ) in onion (3.9 µg kg-1) and sulfathiazole (STZ) in carrot (5.0 µg kg-1). Lower LOQPRO values (0.1-3.7 µg kg-1) were obtained, in general, when dSPE clean-up was employed. Both methods were applied to twenty-five market vegetable samples from ecological and conventional agriculture and only sulfamethazine (SMZ) and sulfapyridine (SPD) were detected in lettuce at 1.2 µg kg-1 and 0.5 µg kg-1, respectively.

CRISPR/Cas13-Based Platforms for a Potential Next-Generation Diagnosis of Colorectal Cancer through Exosomes Micro-RNA Detection: A Review.

Colorectal cancer (CRC) is the third most prevalent cancer with the second highest mortality rate worldwide. CRC is a heterogenous disease with multiple risk factors associated, including obesity, smoking, and use of alcohol. Of total CRC cases, 60% are diagnosed in late stages, where survival can drop to about 10%. CRC screening programs are based primarily on colonoscopy, yet this approach is invasive and has low patient adherence. Therefore, there is a strong incentive for developing molecular-based methods that are minimally invasive and have higher patient adherence. Recent reports have highlighted the importance of extracellular vesicles (EVs), specifically exosomes, as intercellular communication vehicles with a broad cargo, including micro-RNAs (miRNAs). These have been syndicated as robust candidates for diagnosis, primarily for their known activities in cancer cells, including immunoevasion, tumor progression, and angiogenesis, whereas miRNAs are dysregulated by cancer cells and delivered by cancer-derived exosomes (CEx). Quantitative polymerase chain reaction (qPCR) has shown good results detecting specific cancer-derived exosome micro-RNAs (CEx-miRNAs) associated with CRC, but qPCR also has several challenges, including portability and sensitivity/specificity issues regarding experiment design and sample quality. CRISPR/Cas-based platforms have been presented as cost-effective, ultrasensitive, specific, and robust clinical detection tools in the presence of potential inhibitors and capable of delivering quantitative and qualitative real-time data for enhanced decision-making to healthcare teams. Thereby, CRISPR/Cas13-based technologies have become a potential strategy for early CRC diagnosis detecting CEx-miRNAs. Moreover, CRISPR/Cas13-based platforms' ease of use, scalability, and portability also showcase them as a potential point-of-care (POC) technology for CRC early diagnosis. This study presents two potential CRISPR/Cas13-based methodologies with a proposed panel consisting of four CEx-miRNAs, including miR-126, miR-1290, miR-23a, and miR-940, to streamline novel applications which may deliver a potential early diagnosis and prognosis of CRC.

Esporotricosis, una realidad aún presente en Chile: a propósito de un caso / Sporotrichosis, a reality still present in Chile: a case report

OBJETIVO: Reportar un caso de esporotricosis linfocutánea contraída en Chile y realizar una revisión de la literatura con énfasis en los hallazgos dermatoscópicos de las lesiones y en los casos reportados en el país. CASO CLÍNICO: Paciente adulto mayor con lesiones nodulares ulceradas siguiendo trayecto linfático en extremidad superior derecha. RESULTADOS: Estudio micológico confirmó la presencia de Sporothrix schenckii. Se inició tratamiento con antifúngico oral con buena respuesta terapéutica. CONCLUSIONES: Existe un escaso número de reporte de esporotricosis linfocutánea contraída en Chile con confirmación micológica. Este es el único caso chileno con descripción dermatoscópica de las lesiones.

OBJETIVE: To report a case of lymphocutaneous sporotrichosis adquired in Chile and provide a review of the literature with emphasis on dermoscopic findings and previous cases reported in the country. CLINICAL CASE: An elderly patient presented with ulcerated nodular lesions following lymphatic vessels in his right upper limb.RESULTS: Mycological work-up confirmed the presence of Sporothrix schenkii. Oral antifungal treatment was initiated with good therapeutic response. CONCLUSIONS: Few case reports of lymphocutaneous sporotricosis adquired in Chile can be found in literature. Until now this is the only chilean case with dermoscopic description of the lesions.

Antibiotic resistance in bacterial isolates from freshwater samples in Fildes Peninsula, King George Island, Antarctica.

Anthropic activity in Antarctica has been increasing considerably in recent years, which could have an important impact on the local microbiota affecting multiple features, including the bacterial resistome. As such, our study focused on determining the antibiotic-resistance patterns and antibiotic-resistance genes of bacteria recovered from freshwater samples collected in areas of Antarctica under different degrees of human influence. Aerobic heterotrophic bacteria were subjected to antibiotic susceptibility testing and PCR. The isolates collected from regions of high human intervention were resistant to several antibiotic groups, and were mainly associated with the presence of genes encoding aminoglycosides-modifying enzymes (AMEs) and extended-spectrum ß-lactamases (ESBLs). Moreover, these isolates were resistant to synthetic and semi-synthetic drugs, in contrast with those recovered from zones with low human intervention, which resulted highly susceptible to antibiotics. On the other hand, we observed that zone A, under human influence, presented a higher richness and diversity of antibiotic-resistance genes (ARGs) in comparison with zones B and C, which have low human activity. Our results suggest that human activity has an impact on the local microbiota, in which strains recovered from zones under anthropic influence were considerably more resistant than those collected from remote regions.

Genetic Features of Antarctic Acinetobacter radioresistens Strain A154 Harboring Multiple Antibiotic-Resistance Genes.

While antibiotic-resistant bacteria have been detected in extreme environments, including Antarctica, to date there are no reports of Acinetobacter species isolated from this region. Here, we characterized by whole-genome sequencing (WGS) the genetic content of a single antibiotic-resistant Acinetobacter spp. isolate (A154) collected in Antarctica. The isolate was recovered in 2013 from soil samples at Fildes Peninsula, Antarctica, and was identified by detection of the intrinsic OXA-23 gene, and confirmed by Tetra Correlation Search (TCS) and WGS. The antibiotic susceptibility profile was determined by disc diffusion, E-test, and broth microdilution methods. From WGS data, the acquired resistome and insertion sequence (IS) content were identified by in silico analyses. Plasmids were studied by the alkaline lysis method followed by pulsed-field gel electrophoresis and conventional PCR. The A154 isolate was identified as A. radioresistens by WGS analysis and displayed >99.9 of similarity by TCS in relation with the databases. Moreover, it was resistant to ampicillin, ceftriaxone, ceftazidime, cefepime, cefotaxime, streptomycin, and kanamycin. Likewise, in addition to the intrinsic blaOXA-23-like gene, A154 harbored the plasmid-encoded antibiotic-resistance genes blaPER-2, tet(B), aph(3')-Vla, strA, and strB, as well as a large diversity of ISs. This is the first report of antibiotic-resistant A. radioresistens in Antarctica. Our findings show the presence of several resistance genes which could be either intrinsic or acquired in the region.

Multiclass Alpha Integration of Scores from Multiple Classifiers.

Alpha integration methods have been used for integrating stochastic models and fusion in the context of detection (binary classification). Our work proposes separated score integration (SSI), a new method based on alpha integration to perform soft fusion of scores in multiclass classification problems, one of the most common problems in automatic classification. Theoretical derivation is presented to optimize the parameters of this method to achieve the least mean squared error (LMSE) or the minimum probability of error (MPE). The proposed alpha integration method was tested on several sets of simulated and real data. The first set of experiments used synthetic data to replicate a problem of automatic detection and classification of three types of ultrasonic pulses buried in noise (four-class classification). The second set of experiments analyzed two databases (one publicly available and one private) of real polysomnographic records from subjects with sleep disorders. These records were automatically staged in wake, rapid eye movement (REM) sleep, and non-REM sleep (three-class classification). Finally, the third set of experiments was performed on a publicly available database of single-channel real electroencephalographic data that included epileptic patients and healthy controls in five conditions (five-class classification). In all cases, alpha integration performed better than the considered single classifiers and classical fusion techniques.

A New Surrogating Algorithm by the Complex Graph Fourier Transform (CGFT).

The essential step of surrogating algorithms is phase randomizing the Fourier transform while preserving the original spectrum amplitude before computing the inverse Fourier transform. In this paper, we propose a new method which considers the graph Fourier transform. In this manner, much more flexibility is gained to define properties of the original graph signal which are to be preserved in the surrogates. The complex case is considered to allow unconstrained phase randomization in the transformed domain, hence we define a Hermitian Laplacian matrix that models the graph topology, whose eigenvectors form the basis of a complex graph Fourier transform. We have shown that the Hermitian Laplacian matrix may have negative eigenvalues. We also show in the paper that preserving the graph spectrum amplitude implies several invariances that can be controlled by the selected Hermitian Laplacian matrix. The interest of surrogating graph signals has been illustrated in the context of scarcity of instances in classifier training.

Obstrucción duodenal debido a páncreas anular en etapa neonatal / Duodenal obstruction due to annular pancreas during the neonatal period / Obstrução duodenal por pâncreas anular no estágio neonatal

Introducción. El páncreas anular es una infrecuente anomalía congénita caracterizada por un anillo de tejido pancreático rodeando la porción descendente del duodeno, representa el 1 % de las obstrucciones intestinales neonatales a nivel mundial. El diagnóstico y tratamiento definitivo es quirúrgico. El objetivo es describir un caso clínico neonatal con páncreas anular, abordando una revisión reducida de la literatura en su diagnóstico, evolución y tratamiento. Reporte de Caso. Paciente femenina de 24 días de vida con episodios eméticos desde el segundo día de vida, asociado a pérdida de peso e inestabilidad hidroelectrolítica, quien ingresa a la unidad de cuidados intensivos neonatal para manejo. Dada persistencia de sintomatología gastrointestinal e inestabilidad hemodinámica, a pesar de manejo instaurado y ante la alta sospecha de obstrucción intestinal, se procede a realizar examen radiológico de vías digestivas altas con medio de contraste, donde se evidencia signos de estenosis duodenal. Se realiza laparotomía con evidencia de dilatación de segunda y tercera porción del duodeno, paredes engrosadas, cruzado por segmento de páncreas que ocluye su luz totalmente, que corresponde a páncreas anular. Discusión. Tener presente esta entidad dentro de los diagnósticos diferenciales de las obstrucciones duodenales dado que la sintomatología, así como se evidencia en la paciente cambia según el tipo de obstrucción; es necesario solicitar métodos imagenológicos para evaluar signos radiológicos, a fin de esclarecer el diagnóstico y evitar retrasos en el diagnóstico definitivo de páncreas anular, que se realiza por intervención quirúrgica. Conclusión. El páncreas anular sigue siendo un reto diagnóstico dada su infrecuencia. Además, cursa con sintomatología variable e inespecífica, siendo más frecuente el vómito, como fue evidenciado en el caso como el síntoma inicial. Conocer la patología obstructiva duodenal es importante, ya que se encuentra dentro de los diagnósticos diferenciales, ayudando así a evitar retrasos en el abordaje quirúrgico y diagnóstico. Cómo citar: Ortiz-Hernández YV, Ferreira-Traslaviña HH, Duarte-Vergara LM, Africano-León ML. Obstrucción duodenal debido a páncreas anular en etapa neonatal. MedUNAB. 2019;22(1):79-87. doi. org/10.29375/01237047.3423

Introduction. Annular pancreas is an infrequent birth defect characterized by a ring of pancreatic tissue that surrounds the descending part of the duodenum. It accounts for 1 % of neonatal intestinal obstructions worldwide. Diagnosis and final treatment is surgical. The objective is to describe a neonatal clinical case with annual páncreas based on a brief literature review on its diagnosis, evolution and treatment. Case Report. Female patient, 24 days old with emetic episodes starting on the second day of life, associated with loss of weight and hydroelectrolytic instability, who was admitted to the neonatal intensive care unit for management purposes. Given the persistence of the gastrointestinal symptoms and hemodynamic instability, despite the treatment in place, and high level of suspicion of intestinal obstruction, radiology exam of upper digestive tract was performed with contrast medium, finding evidence of signs of duodenal stenosis. Laparotomy was performed, finding evidence of dilation of the second and third parts of the duodenum, thickened walls, crossed by a páncreas segment that fully occludes the light, consistent with annual pancreas. Discussion. Take the above into consideration during differential diagnoses of duodenal obstructions, given that the patient's symptoms, as evidenced in the patient, change depending on the type of obstruction. Imaging methods must be requested to assess radiological signs, in order to clarify the diagnosis and prevent delays in the final diagnosis of annual pancreas, which is performed by means of surgical intervention. Conclusions. Annual pancreas continues to be a diagnostic challenge due to its infrequency. People suffering from this, experience variable and non-specific symptoms; more frequently vomiting, which, in this specific case, was the initial symptom. It is important to learn about the obstructive duodenal pathology, because it is one of the differential diagnoses, and thereby prevents delays in the surgical and diagnostic approach. Cómo citar: Ortiz-Hernández YV, Ferreira-Traslaviña HH, Duarte-Vergara LM, Africano-León ML. Obstrucción duodenal debido a páncreas anular en etapa neonatal. MedUNAB. 2019;22(1):79-87. doi. org/10.29375/01237047.3423

Introdução. O pâncreas anular é uma anomalia congênita rara, caracterizada por um anel de tecido pancreático em torno da porção descendente do duodeno; representa 1 % das obstruções intestinais neonatais em todo o mundo. O diagnóstico e tratamento definitivo é cirúrgico. O objetivo é descrever um caso clínico neonatal com páncreas anular, a partir da revisão reduzida da literatura em seu diagnóstico, evolução e tratamento. Apresentação do caso. Paciente do sexo feminino, 24 dias de vida, com episódios eméticos a partir do segundo dia de vida, associada à perda de peso e distúrbio hidroeletrolítico, que ingressa na unidade de terapia intensiva neonatal para tratamento. Dada a persistência de sintomas gastrointestinais e instabilidade hemodinâmica, a pesar do tratamento estabelecido e da alta suspeita de obstrução intestinal, é realizado exame radiológico do trato digestivo superior com meio de contraste, onde há evidencias de estenose duodenal. É realizada uma laparotomia com evidência de dilatação da segunda e terceira porção do duodeno, paredes espessadas, cruzadas por segmento de pâncreas que oclua completamente sua luz, que corresponde ao pâncreas anular. Discussão. Considerar essa entidade nos diagnósticos diferenciais de obstruções duodenais, uma vez que a sintomatologia, como evidenciado no paciente, muda de acordo com o tipo de obstrução; é necessário solicitar métodos de imagem para avaliar os sinais radiológicos, a fim de esclarecer o diagnóstico e evitar atrasos no diagnóstico definitivo do pâncreas anular que é realizado por meio de intervenção cirúrgica. Conclusões. O pâncreas anular continua a ser um desafio diagnóstico, dada a sua raridade. Além disso, apresenta-se com sintomatologia variável e inespecífica, sendo mais frequente o vômito, que foi evidenciado no caso aqui apresentado, como síntoma inicial. Conhecer a patologia obstrutiva duodenal é importante, pois está dentro dos diagnósticos diferenciais e, assim, ajuda a evitar atrasos na abordagem cirúrgica e no diagnóstico. Cómo citar: Ortiz-Hernández YV, Ferreira-Traslaviña HH, Duarte-Vergara LM, Africano-León ML. Obstrucción duodenal debido a páncreas anular en etapa neonatal. MedUNAB. 2019;22(1):79-87. doi. org/10.29375/01237047.3423

Estrategias de ayuda al rendimiento de alta competición / Support strategies for high competition performance

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Potential adverse cardiac remodelling in highly trained athletes: still unknown clinical significance.

Moderate endurance exercise has long been considered an essential element to maintain cardiovascular health, and sedentary behaviour in the general population has been related to a significant increase in all-causes of mortality, cardiovascular disease mortality and cardiovascular disease incidence. However, a growing group of people performs an intense exercise that leads to multiple heart adaptive changes that are collectively called "athlete's heart". In this review, we discussed the evidence of cardiac remodelling process secondary to repetitive and strenuous exercise in some predisposed athletes that produces intense and probably deleterious changes in cardiac morphology and function with no clear clinical significance in long-term follow-up. Moreover, we also discussed the individual biological response to exercise assessed by myocardial damage, inflammation, oxidative stress, fibrosis and ventricular hypertrophy biomarkers showing different intensities with equivalent exertion.

Probabilistic Distance for Mixtures of Independent Component Analyzers.

Independent component analysis (ICA) is a blind source separation technique where data are modeled as linear combinations of several independent non-Gaussian sources. The independence and linear restrictions are relaxed using several ICA mixture models (ICAMMs) obtaining a two-layer artificial neural network structure. This allows for dependence between sources of different classes, and thus, a myriad of multidimensional probability density functions can be accurate modeled. This paper proposes a new probabilistic distance (PDI) between the parameters learned for two ICAMMs. The PDI is computed explicitly, unlike the popular Kullback-Leibler divergence (KLD) and other similar metrics, removing the need for numerical integration. Furthermore, the PDI is symmetric and bounded within 0 and 1, which enables its use as a posterior probability in fusion approaches. In this paper, the PDI is employed for change detection by measuring the distance between two ICAMMs learned in consecutive time windows. The changes might be associated with relevant states from a process under analysis that are explicitly reflected in the learned ICAMM parameters. The proposed distance was tested in two challenging applications using simulated and real data: 1) detecting flaws in materials using ultrasounds and 2) detecting changes in electroencephalography signals from humans performing neuropsychological tests. The results demonstrate that the PDI outperforms the KLD in change-detection capabilities.

Computing the Partial Correlation of ICA Models for Non-Gaussian Graph Signal Processing.

Conventional partial correlation coefficients (PCC) were extended to the non-Gaussian case, in particular to independent component analysis (ICA) models of the observed multivariate samples. Thus, the usual methods that define the pairwise connections of a graph from the precision matrix were correspondingly extended. The basic concept involved replacing the implicit linear estimation of conventional PCC with a nonlinear estimation (conditional mean) assuming ICA. Thus, it is better eliminated the correlation between a given pair of nodes induced by the rest of nodes, and hence the specific connectivity weights can be better estimated. Some synthetic and real data examples illustrate the approach in a graph signal processing context.

Tejido tiroideo y láser infrarrojo: un estudio morfométrico / Thyroid tissue and infrared laser: a morphometric study

La glándula tiroides posee gran importancia debido a la síntesis y secreción de hormonas, las cuales desempeñan funciones fundamentales para la mantención de la fisiología animal. En este contexto, el objetivo del presente trabajo consistió en determinar parámetros morfométricos de estructuras tiroideas sometidas a estimulaciones con láser infrarrojo (LIR). Para ello, 10 ratas Sprague Dawley de 3 meses de vida y peso aproximado de 200 g, fueron divididas en dos grupos de 5 animales cada uno: grupo control y grupo experimental. Estos últimos recibieron estimulaciones infrarrojas en la tiroides con dosis de 16 J/cm2 durante 15 días seguidos. Una vez sacrificadas las ratas, se extrajeron las glándulas tiroides las que fueron procesadas para microscopía óptica obteniéndose placas histológicas y micrografías con aumentos finales de hasta 1000 X. Se efectuaron estudios morfométricos para determinar en 40 placas, variaciones tisulares generadas por las inducciones infrarrojas, con especial énfasis en la disposición coloidal y dimensiones de folículos y células tiroideas. El análisis de las 40 placas histológicas generados por las inducciones del láser infrarrojo comparados con los controles, reveló que existen marcadas diferencias en todos los componentes del tejido tiroideo analizado, lo cual podría otorgar antecedentes de diferentes funcionalidades en el metabolismo de las glándulas.

The thyroid gland is of great importance because of the synthesis and secretion of hormones which play key roles in the maintenance of animal physiology. In this context, the aim of the present study was to determine morphometric parameters of thyroid structures subjected to infrared laser stimulation (ILS) and for this purpose, 10 Sprague Dawley rats, 3 months of age and weighing approximately 200 grams, were divided into two groups of 5 animals each: the control group and the remaining 5 animals constituting the experimental group received infrared stimulation in the thyroid with doses of 16 J/cm2 for 15 consecutive days. After the rats were sacrificed, the respective thyroids were removed and processed for optical microscopy. Histological plates and micrographs were obtained with final increases of up to 1000 X. Morphometric studies were carried out to determine the tissue variations generated by infrared inductions, with special emphasis on the colloidal arrangement and dimensions of follicles and thyroid cells. Our results revealed that there are marked differences in all the components of the analyzed thyroid tissue which could give antecedents of different functionalities in the metabolism of thyroid glands.

Chitosan doped with nanoparticles of copper, nickel and cobalt.

Metal colloids in 2 propanol using nanoparticles (NPs) of copper, nickel and cobalt were prepared by Chemical Liquid Deposition (CLD) method. The resulting colloidal dispersions were characterized by Transmission Electron Microscopy (TEM). The colloids were supported in chitosan. Then, microbiological assays were performed using E. coli and S. aureus in order to determine the bactericide/bacteriostatic activity of nanoparticles (NPs) trapped or chelated with chitosan. Finally, the toxicity of the metal colloids Cu, Ni and Co was tested. Bio-assays were conducted in three different animal species. First of all on earth warms (Eisenia foetida) to evaluate the toxicity and the biocompatibility of chitosan in lactic acid (1% and 0.5%). Secondly bio-assay done in fishes (rainbow trout), the liver toxicity of NPs in vivo was evaluated. Finally, a bio-assay was conducted in Sprange-Dawley rats of 100g weight, which were injected intraperitoneally with different solutions of chitosan metal colloids. Then, the minimum and maximum concentration were determined for copper, nickel and cobalt. The purpose of the use of chitosan was acting as a carrier for some magnetic NPs, which toxicity would allow to obtain new polymeric materials with potential applications as magnet future drugs carrier.