Fish acute toxicity of nine nanomaterials: Need of pre-tests to ensure comparability and reuse of data.

Fish acute toxicity tests are commonly used in aquatic environmental risk assessments, being required in different international substances regulations. A general trend in the toxicity testing of nanomaterials (NMs) has been to use standardized aquatic toxicity tests. However, as these tests were primarily developed for soluble chemical, issues regarding particle dissolution, agglomeration or sedimentation during the time of exposure are not considered when reporting the toxicity of NMs. The aim of this study was to characterize the NM behaviour throughout the fish acute test and to provide criteria to assay the toxicity of nine NMs based on TiO2, ZnO, SiO2, BaSO4, bentonite, and carbon nanotubes, on rainbow trout following OECD Test Guideline (TG) nº203. Our results showed the importance of conducting a preliminary test (without fish) when working with NMs. They provide valuable information on, sample monitoring, agglomeration, sedimentation, dissolution, actual concentrations of NMs, needed to design the test. Among the NMs tested, only bentonite nanoparticles were stable during the 96-h pre-test and test in aquarium water. In contrast, the remaining NMs exhibited considerable loss and sedimentation within the first 24 h. The high sedimentation observed for almost all NMs highlights the need of consistently measuring the concentrations throughout the entire duration of the fish acute toxicity test to make reliable concentration-response relationships. Notable differences emerged in LC50 values when using actual concentrations as nominal concentrations overestimated concentrations by up to 85.6%. Among all NMs tested, only ZnO NMs were toxic to rainbow trout. A flow chart was specifically developed for OECD TG 203, aiding users in making informed decisions regarding the selection of test systems and necessary modifications to ensure accurate, reliable, and reusable toxicity data. Our findings might contribute to the harmonization of TG 203 improving result reproducibility and interpretability and supporting the development of read-across and QSAR models.

[Response to the letter to the editor of "Commentary on the COVID-19 mRNA vaccine reactogenicity study"]. / Respuesta a la carta al editor de "Comentario al Estudio de reactogenicidad de la vacuna ARNm de COVID-19".

Dear Editor, Our study aims to compare the short-term adverse effects and their consequences between the RNAm vaccines Commirnaty® (Pfizer) and Spikevax® (Moderna), as well as these short-term adverse effects and their consequences between the first and second doses of these vaccines with each other. Possible long-term adverse effects were not the subject of our study….

Querido editor, Nuestro estudio tiene por objetivo, comparar los efectos adversos a corto plazo y sus consecuencias entre las vacunas RNAm, Commirnaty® (Pfizer) y Spikevax® (Moderna), así como, estos efectos adversos a corto plazo y sus consecuencias entre la primera y la segunda dosis de las citadas vacunas entre sí. Los posibles efectos adversos a largo plazo no eran objeto de nuestro estudio….

[Reactogenicity Study of mRNA Vaccines Against COVID-19]. / Estudio de reactogenicidad en las vacunas mRNA frente a la COVID-19.

OBJECTIVE: To compare the reactogenicity between the types of mRNA Commirnaty® (Pfizer) and Spikevax® (Moderna) vaccines against COVID-19 in a healthcare population. METHODS: Cross sectional study of short-term adverse effects and their consequences (sick leave, limitations of daily life, etc.) after the administration of the first and second doses of both vaccines in professionals and students of a health institution. A questionnaire on symptoms and their consequences was administered seven days after each vaccination dose. The prevalence and 95% confidence interval (95%CI) were calculated. Differences between vaccines were quantified using the odds ratio (OR) and its 95%CI. RESULTS: The questionnaire was completed by 1924 and 1170 healthcare providers (response rates 62.2% and 39.1%) after the first and second doses, respectively, of the Commirnaty® vaccine, and 410 (56.0%) and 107 (15.0%) of Spikevax®. After the first dose of Comirnaty®, 67.4% presented some adverse effect, and 76.1% for Spikevax® (OR 1.5 95%CI 1.2-1.9). In general, women and young people showed greater reactogenicity and differences between vaccinSpain. Consequences of adverse effects were more frequent for Spikevax®. The reactogenicity was higher after the second than the first dose, for both vaccines (Comirnaty®: 67.4% vs. 75.6%; Spikevax®: 76.1% vs. 87.9%. CONCLUSIONS: The greater reactogenicity and its consequences, for the first and second dose of the Spikevax® vaccine compared to Comirnaty®, and of the second dose compared to the first dose of both vaccines, provides useful knowledge for planning vaccination against COVID-19 campaigns in healthcare settings.

OBJETIVO: Comparar la reactogenicidad entre los tipos de vacuna RNAm Commirnaty® (Pfizer) y Spikevax® (Moderna) frente a la COVID-19 en población sanitaria. Métodos: Estudio de prevalencia de los efectos adversos a corto plazo y sus consecuencias tras la administración de la primera y segunda dosis en profesionales y estudiantes de una institución sanitaria. Se administró un cuestionario de síntomas y sus consecuencias a los 7 días de la vacunación. Se calculó la prevalencia e intervalo de confianza del 95% (IC95%). Las diferencias entre vacunas se cuantificaron mediante las odds ratio (OR) e IC95%. RESULTADOS: Completaron el cuestionario 1924 y 1170 sanitarios (tasas de respuesta 62.2% y 39.1%) tras la primera y la segunda dosis, respectivamente, de la vacuna Commirnaty®, y 410 (56.0%) y 107 (15.0%), de Spikevax®. Después de la primera dosis de Comirnaty® un 67,4% presentó algún efecto adverso, y un 76,1% para Spikevax® (OR 1,5 IC95% 1,2-1,9). En general mujeres y jóvenes mostraron mayor reactogenicidad y diferencias entre vacunas. Las consecuencias de los efectos adversos fueron más frecuentes para Spikevax®. La reactogenicidad fue superior tras la segunda dosis que tras la primera, para las dos vacunas (Comirnaty® 67,4% vs. 75,6%; Spikevax® 76,1% vs. 87,9%). CONCLUSIONES: La mayor reactogenicidad y sus consecuencias, para la primera y segunda dosis de la vacuna Spikevax® respecto a Comirnaty®, y de la segunda dosis respecto a la primera dosis de ambas vacunas, aporta conocimiento útil para la planificación de campañas de vacunación frente a la COVID-19 en el entorno sanitario.

Estudio de reactogenicidad en las vacunas mRNA frente a la COVID-19 / Reactogenicity Study of mRNA Vaccines Against COVID-19

Objetivo: Comparar la reactogenicidad entre los tipos de vacuna RNAm Commirnaty® (Pfizer) y Spikevax® (Moderna) frente a la COVID-19 en población sanitaria.Métodos: Estudio de prevalencia de los efectos adversos a corto plazo y sus consecuencias tras la administración de la primera y segunda dosis en profesionales y estudiantes de una institución sanitaria. Se administró un cuestionario de síntomas y sus consecuencias a los 7 días de la vacunación. Se calculó la prevalencia e intervalo de confianza del 95% (IC95%). Las diferencias entre vacunas se cuantificaron mediante las odds ratio (OR) e IC95%.Resultados: Completaron el cuestionario 1924 y 1170 sanitarios (tasas de respuesta 62.2% y 39.1%) tras la primera y la segunda dosis, respectivamente, de la vacuna Commirnaty®, y 410 (56.0%) y 107 (15.0%), de Spikevax®. Después de la primera dosis de Comirnaty® un 67,4% presentó algún efecto adverso, y un 76,1% para Spikevax® (OR 1,5 IC95% 1,2-1,9). En general mujeres y jóvenes mostraron mayor reactogenicidad y diferencias entre vacunas. Las consecuencias de los efectos adversos fueron más frecuentes para Spikevax®. La reactogenicidad fue superior tras la segunda dosis que tras la primera, para las dos vacunas (Comirnaty® 67,4% vs. 75,6%; Spikevax® 76,1% vs. 87,9%).Conclusiones: La mayor reactogenicidad y sus consecuencias, para la primera y segunda dosis de la vacuna Spikevax® respecto a Comirnaty®, y de la segunda dosis respecto a la primera dosis de ambas vacunas, aporta conocimiento útil para la planificación de campañas de vacunación frente a la COVID-19 en el entorno sanitario. (AU)

Objective: To compare the reactogenicity between the types of mRNA Commirnaty® (Pfiz-er) and Spikevax® (Moderna) vaccines against COVID-19 in a healthcare population.Methods: Cross sectional study of short-term adverse effects and their consequences (sick leave, limitations of daily life, etc.) after the administration of the first and second doses of both vaccines in professionals and students of a health institution. A questionnaire on symptoms and their consequences was administered seven days after each vaccination dose. The prevalence and 95% confidence interval (95%CI) were calculated. Differences be-tween vaccines were quantified using the odds ratio (OR) and its 95%CI.Results: The questionnaire was completed by 1924 and 1170 healthcare providers (re-sponse rates 62.2% and 39.1%) after the first and second doses, respectively, of the Com-mirnaty® vaccine, and 410 (56.0%) and 107 (15.0%) of Spikevax®. After the first dose of Comirnaty®, 67.4% presented some adverse effect, and 76.1% for Spikevax® (OR 1.5 95%CI 1.2-1.9). In general, women and young people showed greater reactogenicity and differences between vaccines. Consequences of adverse effects were more frequent for Spikevax®. The reactogenicity was higher after the second than the first dose, for both vaccines (Comirnaty®: 67.4% vs. 75.6%; Spikevax®: 76.1% vs. 87.9%Conclusions: The greater reactogenicity and its consequences, for the first and second dose of the Spikevax® vaccine compared to Comirnaty®, and of the second dose com-pared to the first dose of both vaccines, provides useful knowledge for planning vaccination against COVID-19 campaigns in healthcare settings (AU)

Selenium stress response of the fruit origin strain Fructobacillus tropaeoli CRL 2034.

The fruit-origin strain Fructobacillus tropaeoli CRL 2034 can biotransform selenium into seleno-nanoparticles and selenocysteine. The proteomic analysis of F. tropaeoli CRL 2034 exposed to 5 and 100 ppm of Se showed a dose-dependent response since 19 and 77 proteins were deregulated, respectively. In the presence of 5 ppm of Se, the deregulated proteins mainly belonged to the categories of energy production and conversion or had unknown functions, while when cells were grown with 100 ppm of Se, most of the proteins were grouped into amino acid transport and metabolism, nucleotide transport and metabolism, or into unknown functions. However, under both Se conditions, glutathione reductases were overexpressed (1.8-3.1-fold), while mannitol 2-dehydrogenase was downregulated (0.54-0.19-fold), both enzymes related to oxidative stress functions. Mannitol 2-dehydrogenase was the only enzyme found that contained SeCys, and its activity was 1.27-fold increased after 5 ppm of Se exposure. Our results suggest that F. tropaeoli CRL 2034 counteracts Se stress by overexpressing proteins related to oxidative stress resistance and changing the membrane hydrophobicity, which may improve its survival under (food) storage and positively influence its adhesion to intestinal cells. Selenized cells of F. tropaeoli CRL 2034 could be used for producing Se-enriched fermented foods. KEY POINTS: • Selenized cells of F. tropaeoli showed enhanced resistance to oxidative stress. • SeCys was found in the Fructobacillus mannitol 2-dehydrogenase polypeptide chain. • F. tropaeoli mannitol 2-dehydrogenase activity was highest when exposed to selenium.

Characterization of AgNPs and AuNPs in sewage sludge by single particle inductively coupled plasma-mass spectrometry.

This study develops for the first time an analytical method for the characterization of silver and gold nanoparticles in sewage sludge. The evaluation of the effect of temperature, extracting agent and centrifugation speed and time on the extraction yield was carried out through a multifactorial analysis of variance which allows us to select 289 g, 5 min and 20 mM sodium pyrophosphate tetrabasic as optimal extraction conditions. Under these conditions, the analysis of the extract by single particle inductively coupled plasma-mass spectrometry provided recovery percentages of 70 ± 2% and 56 ± 1% for silver and gold nanoparticles, respectively. Moreover, the complementary results obtained upon analysis of these extracts by transmission electron microscopy and single particle inductively coupled plasma-mass spectrometry showed that the developed method did not modify the original size and shape of these nanoparticles during the extraction procedure. Size detection limits of 23 nm and 16 nm as well as number concentration limits of 3.12 × 109 particles kg-1 and 1.38 × 109 particles kg-1 were obtained for silver and gold nanoparticles, respectively. Moreover, a stability study of silver and gold nanoparticles in sewage sludge for 12 months showed differences between the two nanoparticle types. Although the sizes were not affected during the 12 months, silver nanoparticles underwent an oxidation process from 6 months onwards, which was reflected in an increase in the percentage of ionic silver from 14 ± 1% at 6 months to 24 ± 2% at 12 months. The developed methodology represents a simple, reliable and fast tool for detecting, quantifying and assessing the stability of nanoparticles in an important environmental sample such as sewage sludge.

In vivo quantification of volatile organoselenium compounds released by bacteria exposed to selenium with HS-SPME-GC-MS. Effect of selenite and selenium nanoparticles.

Quantification of volatile organoselenium species released by Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), after their growth in the presence of 1 and 2 mg Se·L-1 as both selenite and chitosan-modified selenium nanoparticles (Ch-SeNPs), was achieved by the application of a method based on headspace solid-phase microextraction (HS-SPME) and in-fiber internal standardization, combined with gas chromatography coupled to mass spectrometry (GC-MS). This method consisted of an initial extraction of the released volatile organoselenium compounds on the SPME fiber, followed by the extraction of internal standard (IS), deuterated dimethyl sulfide (d6-DMS), on the same fiber before its desorption at the injection port of GC-MS. The results showed that the biotransformation of selenite and Ch-SeNPs into volatile organoselenium compounds was dependent on both the type of bacterial species and the chemical form of selenium (Se) administered. In this sense, E. coli was able to biotransform both selenite and Ch-SeNPs into dimethylselenium (DMSe) and dimethyldiselenium (DMDSe) while S. aureus, biotransformed selenite into DMSe and DMDSe and, Ch-SeNPs only into DMDSe. Additionally, the formation of a volatile mixed sulfur/selenium compound, dimethyl selenenyl sulfide (DMSeS), from Se in nanoparticulated form has been detected for the first time.

Biotransformation of Selenium by Lactic Acid Bacteria: Formation of Seleno-Nanoparticles and Seleno-Amino Acids.

Selenium (Se) is an essential micronutrient for the majority of living organisms, and it has been identified as selenocysteine in the active site of several selenoproteins such as glutathione peroxidase, thioredoxin reductase, and deiodinases. Se deficiency in humans is associated with viral infections, thyroid dysfunction, different types of cancer, and aging. In several European countries as well as in Argentina, Se intake is below the recommended dietary Intake (RDI). Some lactic acid bacteria (LAB) can accumulate and bio-transform selenite (toxic) into Se-nanoparticles (SeNPs) and Se-amino acids (non-toxic). The microbial growth, Se metabolite distribution, and the glutathione reductase (involved in selenite reduction) activity of Se-enriched LAB were studied in this work. The ninety-six assayed strains, belonging to the genera Lactococcus, Weissella, Leuconostoc, Lactobacillus, Enterococcus, and Fructobacillus could grow in the presence of 5 ppm sodium selenite. From the total, eight strains could remove more than 80% of the added Se from the culture medium. These bacteria accumulated intracellularly between 1.2 and 2.5 ppm of the added Se, from which F. tropaeoli CRL 2034 contained the highest intracellular amount. These strains produced only the seleno-amino acid SeCys as observed by LC-ICP-MS and confirmed by LC-ESI-MS/MS. The intracellular SeCys concentrations were between 0.015 and 0.880 ppm; Lb. brevis CRL 2051 (0.873 ppm), Lb. plantarum CRL 2030 (0.867 ppm), and F. tropaeoli CRL 2034 (0.625 ppm) were the strains that showed the highest concentrations. Glutathione reductase activity values were higher when the strains were grown in the presence of Se except for the F. tropaeoli CRL 2034 strain, which showed an opposite behavior. The cellular morphology of the strains was not affected by the presence of Se in the culture medium; interestingly, all the strains were able to form spherical SeNPs as determined by transmission electron microscopy (TEM). Only two Enterococcus strains produced the volatile Se compounds dimethyl-diselenide identified by GC-MS. Our results show that Lb. brevis CRL 2051, Lb. plantarum CRL 2030, and F. tropaeoli CRL 2034 could be used for the development of nutraceuticals or as starter cultures for the bio-enrichment of fermented fruit beverages with SeCys and SeNPs.

Insights into the accumulation and transformation of Ch-SeNPs by Raphanus sativus and Brassica juncea: Effect on essential elements uptake.

Selenium (Se) at very low doses has important functions for humans. Unfortunately, the low levels of Se in soils in various regions of the world have implemented the agronomic biofortification of crops by applying Se-enriched fertilizers (mainly based on selenate). Lately, the use of nanofertilizers is growing in interest as their low size reduces the amount of chemicals and minimizes nutrient losses in comparison with conventional bulk fertilizers. However, the knowledge on their fate and environmental impact is still scarce. This study aims to evaluate the biotransformation of chitosan-modified Se nanoparticles (Ch-SeNPs) as well as their effect on the metabolism of essential metals (Fe, Cu, Zn and Mo) when applied to hydroponic cultivation of R. sativus and B. juncea. In house-synthesized Ch-SeNPs were characterized in both synthesis and hydroponic culture media by transmission electron microscopy (TEM), dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). The composition of one-tenth strength Hoagland's solution did not affect the size, shape and concentration in number of particles per mL of Ch-SeNPs. The plants were grown inside a box at 25 °C during the months of May-July in 2018. After a week of treatment with Ch-SeNPs, plants were harvested and divided into roots and aerial part. The biotransformation of Ch-SeNPs was evaluated through a process of enzymatic hydrolysis and subsequent analysis by HPLC-ICP-MS and HPLC-ESI-MS/MS. The results confirmed the transformation of Ch-SeNPs to seleno-amino acids: Selenomethionine (SeMet), Semethylselenocysteine (SeMetSeCys) and É£-glutamyl-Se-MetSeCys. Moreover, Multiple-way analysis of variance (ANOVA) and principal component analysis (PCA) showed that, regardless the plant species, Ch-SeNPs supplementation affected the absorption of Zn.

In-vivo solid phase microextraction for quantitative analysis of volatile organoselenium compounds in plants.

A new calibration method based on the use of headspace solid-phase microextraction (HS-SPME) and in-fiber internal standardization, combined with gas chromatography coupled to mass spectrometry (GC/MS) was developed for quantifying Se volatile organic species released by plants exposed to chitosan-modified selenium nanoparticles (Cs-SeNPs). The effect of several parameters affecting extraction and separation of the selected organic species of selenium (dimethylselenium (DMSe), diethylselenium (DESe) and dimethyldiselenium (DMDSe)) and deuterated dimethyl sulphide (d6-DMS) employed as internal standard were studied and optimized using an experimental design. The developed methodology was applied for quantifying the volatile selenium compounds produced over time by the plant species Raphanus sativus and Brassica juncea grown in hydroponic solution containing 5 mg Se L-1 in the form Cs-SeNPs. The procedure employed consisted in two steps. Volatile selenium species released from the plants were first extracted in the SPME fiber located at the headspace of a box with a fixed volume. Subsequently, the internal standard placed in a vial subjected to the same conditions as plants was extracted on the same fiber than the one previously used for extracting selenium compounds. Finally the extracted compounds were separated and analyzed by GC/MS. Results evidenced Cs-SeNPs biotransformation into DMSe and DMDSe by both plants species during growing stage, in amounts of the order of ng. Additionally, the resulting data were submitted to multifactorial ANOVA to evaluate the influence of plant type and time of exposure to Cs-SeNPs on the production of volatile selenium compounds.

Mortalidad materna en Ambato, Ecuador. 2005-2014 / Maternal mortality in Ambato, Ecuador. 2005-2014

Resumen Introducción. La mortalidad materna (MM) es uno de los indicadores sanitarios que evidencia con mayor claridad la inequidad de género para la toma de decisiones y la exclusión social, esto toda vez que demanda una intervención médica urgente encaminada a prevenir una muerte. Objetivo. Exponer la magnitud y la tendencia de la MM en el cantón Ambato entre los años 2005 y 2014. Materiales y métodos. Estudio observacional, descriptivo, retrospectivo y transversal de las muertes maternas ocurridas en Ambato entre los años 2005 y 2014. El universo de estudio estuvo conformado por las 46 muertes maternas ocurridas y 51 947 nacidos vivos. Resultados. Se evidenció un ascenso significativo de la natalidad (r=0.652, p=0.041) y en el número de nacidos vivos con asistencia profesional (r=0.894, p=0.000); la razón de MM acumulada en el periodo fue de 88.6, con una tendencia al descenso no significativa (r=0.12 p=0.743). La enfermedad hipertensiva del embarazo fue la primera causa directa de MM (n=17, 41.5%). Conclusiones. La natalidad ha ido en ascenso y la tendencia de la MM a lo largo de 10 años no ha mostrado cambios significativos. La enfermedad hipertensiva del embarazo ha sido la principal causa de MM.

Abstract Introduction: Maternal mortality (MM) is one of the health indicators that most clearly demonstrates gender inequality in decision-making and social exclusion, since it demands urgent medical intervention aimed at preventing death. Objective: To expose the magnitude and trend of MM in Ambato between 2005 and 2014. Materials and methods: Observational, descriptive, retrospective and cross-sectional study of maternal deaths in Ambato between 2005 and 2014. The study universe consisted of 46 maternal deaths and 51 947 live births. Results: There was a significant increase in the birth rate (r=0.652, p=0.041) and in the number of live births with professional assistance (r=0.894, p=0.000). The cumulative MM ratio in the period was 88.6, with a non-significant downward trend (r=0.12 p=0.743). Hypertensive disease of pregnancy was the first direct cause of MM (n=17, 41.5%). Conclusions: Birth rates have been on the rise and the trend of MM over 10 years has not shown significant changes. Hypertensive disease of pregnancy remains the main cause of MM.

Egresados de la carrera de Enfermería y su perfil profesional / Nursing major graduates and their professional profiles

Introducción: A través de los estudios de seguimiento a graduados se pueden obtener las incompatibilidades e insuficiencias de las competencias disponibles en relación con las competencias necesarias para concretar la estrategia corporativa. Objetivo: Evaluar el perfil profesional y necesidades de formación de los egresados de la Carrera de Enfermería de la Universidad Técnica de Ambato. Métodos: Se realizó un estudio observacional, descriptivo y retrospectivo como parte del seguimiento a graduados de la Carrera de Enfermería. El universo estuvo representado por los 698 graduados de la carrera desde enero del año 2002 hasta diciembre de 2017, no se seleccionó muestra. Resultados: Se evidenció una tendencia ascendente no significativa del número de graduados (r=0,024 IC95 por ciento : 32,81 a 54,94). La mayoría de los graduados se desempeñaron en el área de salud pública (44,4 por ciento) y como empleados públicos (73,7 por ciento). Señalaron como principales asignaturas en su formación la enfermería médico-quirúrgica (35,4 por ciento) y la enfermería gineco-obstétrica (24,6 por ciento), a la vez que demandaron con mayor frecuencia la formación de posgrado en las áreas de emergencias y atención en salud familiar. Conclusiones: A pesar del discreto incremento en el número de graduados, la Carrera de Enfermería de la Universidad Técnica de Ambato ha respondido a su encargo social en cuanto a la formación de talento humano que en mayor medida se ha desempeñado en el sector público(AU)

Introduction: Through follow-up studies of graduates, the incompatibilities and inadequacies of available competences can be obtained in association with the competences necessary to concretize the corporate strategy. Objective: To evaluate the professional profile and the training needs of the Nursing major graduates from Technical University of Ambato. Methods: An observational, descriptive and retrospective study was carried out as part of the follow-up of the Nursing major graduates. The population was represented by the 698 graduates from January 2002 to December 2017. No sample was selected. Results: There was a non-significant trend towards an increase in the number of graduates (r=0.024; 95 percent confidence interval, 32.81 to 54.94). The majority of the graduates worked in the area of public health (44.4 percent) and as public employees (73.7 percent). They mentioned that the main subjects in their training were Medical-Surgical Nursing (35.4 percent) and Gynecological-Obstetric Nursing (24.6 percent), while demanding more frequent postgraduate training in the emergency and family healthcare areas. Conclusions: Despite the discreet increase in the number of graduates, the Nursing major of Technical University of Ambato has responded to its social assignment as to the training of human talent, a personal that has significantly worked in the public sector(AU)

Simultaneous determination of the size and concentration of AgNPs in water samples by UV-vis spectrophotometry and chemometrics tools.

The combination of UV-vis spectrophotometry with a chemometric calibration tool based on partial least squares (PLS) has allowed us the development of a multivariate analytical method that simultaneously estimates the concentration and size of mixtures of silver nanoparticles (AgNPs) in environmental water samples. The method is based on changes in the surface plasmon resonance band (SPRB) of AgNPs when they form aggregated/assembled structures with L-cysteine (L-cys). Measurementts were performed by employed a fixed-time kinetics method that implies that the final spectra (response) are obtained by subtstracting the solutions spectra at fixed times. Optimization of experimental conditions affecting aggregation such as time, temperature, pH and concentration of aggregating substance was performed by experimental design and response surface methodologies (RSM). A multivariate calibration model using AgNPs of known diameter size ((20 ±â€¯3), (41 ±â€¯3), (59 ±â€¯5) and (79 ±â€¯7) nm) within a concentration range between 0.62 and 2.5 mg L-1 was constructed by using a mixture experimental design and PLS. The method was finally applied to estimate size and concentration of AgNPs in AgNPs-spiked river and tap water samples. Water samples were spiked with individual, binary and ternary mixtures of AgNPs of different sizes and by using two types of AgNPs: citrate-coated AgNPs (cit-AgNPs) and polyvinylpyrrolidone-coated AgNPs (PVP-AgNPs). A good correspondence was obtained between predicted values and the total amount of AgNPs added with recovery values ranged within 80-160% for the individual mixtures, 68-108% for the binary mixtures and 60-64% for the ternary mixtures of AgNPs. Finally, transmission electron microscopy (TEM) measurements were performed for those cases where discrepancies between the expected and the obtained values were observed. TEM micrographs evidenced the presence of agglomerates or aggregates of AgNPs in some of the mixtures or water tested.

Determination of size and mass-and number-based concentration of biogenic SeNPs synthesized by lactic acid bacteria by using a multimethod approach.

Selenium nanoparticles (SeNPs) were synthesized by a green technology using lactic acid bacteria (LAB, Lactobacillus acidophilus, L. delbrueckii subsp. bulgaricus and L. reuteri). The exposure of aqueous sodium selenite to LAB led to the synthesis of SeNPs. Characterization of SeNPs by transmission electron microscopy with energy dispersive X-ray spectrum (EDXS) analysis revealed the presence of stable, predominantly monodispersed and spherical SeNPs of an average size of 146 ± 71 nm. Additionally, SeNPs hydrodynamic size was determined by dispersive light scattering (DLS) and nanoparticle tracking analysis (NTA). For this purpose, a methodology based on the use of surfactants in basic medium was developed for isolating SeNPs from the bacterial pellet. The hydrodynamic size values provided by DLS and NTA were 258 ± 4 and 187 ± 56 nm, respectively. NTA measurements of number-based concentration reported values of (4.67±0.30)x109 SeNPs mL-1 with a relative standard deviation lower than 5% (n = 3). The quantitative results obtained by NTA were supported by theoretical calculations. Asymmetrical flow field flow fractionation (AF4) on line coupled to the inductively couple plasma mass spectrometry (ICP-MS) and off-line coupled to DLS was further employed to characterize biogenic SeNPs. The distribution of the particle size for the Se-containing peak provide an average size of (247 ± 14) nm. The data obtained by independent techniques were in good agreement and the developed methodology could be implemented for characterizing NPs in complex matrices such as biogenic nanoparticles embedded inside microbial material.

Análisis de la situación de salud: consultorio 38, Policlínico Hermanos Cruz: Enero-Junio 2005

Se realizó un estudio con una primera etapa de tipo observacional, descriptiva, retrospectiva y una segunda etapa de intervención en la situación de salud de la comunidad perteneciente al consultorio médico familiar 38 del Policlínico Hermanos Cruz. Se analizaron las principales determinantes de salud (modos y estilos de vida, biología humana, medio ambiente y la organización de los servicios de salud) con la finalidad de determinar los principales problemas existentes. A tal fin la información obtenida fue analizada rigurosamente para lograr la identificación, priorización y explicación de los problemas. La existencia de malos hábitos alimentarios, el sedentarismo generalizado, la no existencia de círculo de adolescentes, la baja incorporación de abuelos a su círculo, la presencia de cerdos en el hogar y los riesgos de accidentes en el mismo, fueron los principales factores de riesgo identificados. La baja incorporación de los abuelos a su círculo, la presencia de cerdos en las viviendas y el deficiente servicio de estomatología, fueron los principales problemas identificados. Posteriormente se elaboró un plan de acción con el objetivo de solucionar estos problemas...(AU)

Actualización fisiopatológica del síndrome de respuesta inflamatoria sistémica

El Síndrome de Respuesta Inflamatoria Sistémica es la respuesta observable ante una variedad de insultos severos, pero no estando limitados sólo a la infección. Su fisiopatología resulta de la interacción de los diferentes mediadores solubles de la respuesta inflamatoria y antinflamatoria determinando fases evolutivas que van desde la respuesta inflamatoria local, la cual puede convertirse en sistémica y evolucionar hacia una parálisis inmunológica y la disonancia inmunológica. En el presente trabajo ponemos a la luz los más recientes conocimientos en torno a la fisiopatología del SIRS, abordando sus mecanismos y principales mediadores. Con la presente revisión podemos concluir que el síndrome se desencadena por diferentes disparadores, expresando la acción de un complejo sistema defensivo, quien determina, por el equilibrio entre la respuesta proinflamatoria y antinflamatoria las distintas fases evolutivas, todo lo cual de no controlarse y amplificarse lleva al paciente a una disfunción múltiple de órganos...(AU)

Nivel de consentimiento informado en el Servicio de Medicina Interna del Hospital Abel Santamaría

Con el objetivo de investigar el nivel en que se encuentra el Consentimiento Informado con respecto a la realización de exámenes complementarios, fueron escogidos 136 pacientes en el servicio de Medicina Interna del Hospital Abel Santamaría en Pinar del Río, a los que se les realizaron exámenes complementarios en días posteriores. Fueron entrevistados con preguntas previamente preparadas, obteniéndose que la mayoría de nuestros pacientes conocen que se les va a realizar el estudio complementario con anticipación a la realización de este, siendo el médico el que con mayor frecuencia brinda esta información, que la causa de la realización del estudio es conocida en la mayoría de los pacientes. Además existe un conocimiento aceptable en cuanto a cómo se realiza el estudio, en la mayoría de los pacientes. De modo general no se conocen los riesgos de la realización del estudio complementario previo a la realización de este. Por lo que el conocimiento de información con respecto al estudio complementario se ordena decrecientemente en: el paciente sabe que se va a realizar el estudio, causa de su realización y procedimiento para hacerlo, riesgos que implica el estudio. Concluyendo además que el nivel en que se encuentra el consentimiento informado es inicial o primario...(AU)