[Caso clínico: síndrome de DRESS por hidroxicloroquina].

Background: DRESS syndrome (Drug reaction with eosinophilia and systemic symptoms) is an idiosyncratic reaction characterized by peripheral eosinophilia and systemic symptoms: fever, exanthema, lymphadenopathy, hepatitis, atypical lymphocytes and elevated liver enzymes. The incidence is 1 per 10,000 exposures, mortality 10-20%. Treatment is based on suspension of the suspected drug and steroids. Case report: A 42-year-old male with the following important antecedents. AHF: mother and father with Diabetes Mellitus type 2. APP: Arterial Hypertension, Diabetes Mellitus type 2, and bee sting allergy. Current Condition: He started 8 days after ingestion of hydroxychloroquine for probable SARS-COV-2 infection, with headache, facial and neck edema, desquamative dermatosis on trunk and upper extremities, went to private clinic with torpid evolution sent to third level for increased facial and neck edema, which merited orotracheal intubation, management with intravenous steroids and antihistamines. Labs on admission: Leukocytes 20090, platelets 322 thousand, eosinophilia (5%), elevated liver enzymes and acute kidney injury, fulfilling J-SCAR criteria. The patient was discharged due to adequate evolution with follow-up by Allergy and Clinical Immunology, the patient persists with desquamative lesions after 4 weeks and normalization of laboratory parameters. Conclusions: DRESS is a delayed adverse reaction. It is important the diagnostic presumption and the causal relationship with the drugs due to the high mortality rate.

Antecedentes: El síndrome DRESS (Drug reaction with eosinophilia and systemic symptoms) es una reacción idiosincrática, se caracteriza por eosinofilia perifé- rica y síntomas sistémicos: fiebre, exantema, linfadenopatía, hepatitis, linfocitos atípicos y elevación de enzimas hepáticas. La incidencia es de 1 por cada 10,000 exposiciones, mortalidad de 10 a 20%. El tratamiento se basa en la suspensión del fármaco sospechoso y en la aplicación de esteroides. Reporte de caso: Masculino de 42 años con los siguientes antecedentes de importancia. AHF: madre y padre con Diabetes Mellitus tipo 2. APP: Hipertensión Arterial, Diabetes Mellitus tipo 2, y alergia a picadura de abeja. Padecimiento Actual: Lo inicia posterior a 8 días tras la ingesta de hidroxicloroquina por probable infección por SARS-COV-2, con cefalea, edema facial y de cuello, dermatosis descamativa en tronco y extremidades superiores, acude a clínica particular con evolución tórpida enviado a tercer nivel por aumento de edema facial y cuello, que amerito intubación orotraqueal, manejo con esteroides intravenosos y anti- histamínicos. Laboratorios a su ingreso: Leucocitos 20090, plaquetas 322 mil, eosinofilia (5%), elevación de enzimas hepáticas y lesión renal aguda, cumpliendo criterios J-SCAR. Se egresa por adecuada evolución con seguimiento por Alergia e Inmunología Clínica, el paciente persiste con lesiones descamativas posterior a 4 semanas y normalización de parámetros de laboratorios. Conclusión: DRESS es una reacción adversa retardada. Es importante la presunción diagnóstica y la relación causal con los fármacos por la alta tasa de morta- lidad.

Concept of opportunistic bilateral salpingectomy in a sample of Mexican gynecologists. What should residents be trained on? / Concepto de salpingectomía bilateral oportunista en una muestra de ginecólogos mexicanos. ¿En qué se debe capacitar a los residentes?

Background: Ovarian cancer is the fifth deadliest cancer among women. There is no effective screening method. It has been suggested that ovarian cancer originates from precursor lesions in the fimbriae of the fallopian tubes. Objective: The aim of this study was to determine the level of knowledge of opportunistic bilateral salpingectomy by gynecologists. Methods: A cross-sectional study was carried out and a survey was sent electronically to gynecologists and gynecology residents. Demographic characteristics as well as questions of interest related to clinical practice and indication for surgery were included. Results: 52 subjects were included, 21 women and 31 men, with a mean age of 40.7 years. Thirty-five board certified gynecologists, as well as 17 gynecology residents, were included as part of the total survey group. Thirty-six individuals (69.2%) reported performing elective salpingectomy. The motivation they had to perform salpingectomy as a method of sterilization was: “reduction in the risk of ovarian cancer in the future” (55.6%). The indication for elective salpingectomy while performing other procedures was: “to prevent ovarian cancer” (61.1%). Certified gynecologists (42.9%) as well as residents (41.1%) considered “transvaginal ultrasound screening” as the best primary prevention method for ovarian cancer in low-risk women. Conclusions: Opportunistic bilateral salpingectomy is safe and cost-effective. However, when gynecologists are interviewed to find out their level of knowledge, there is poor acceptance of opportunistic bilateral salpingectomy in Mexico. A training strategy should be designed in the gynecology residency in order to motivate ovarian cancer prevention.(AU)

Antecedentes: El cáncer de ovario es el quinto cáncer más mortal entre las mujeres. No existe un método de detección eficaz. Se ha sugerido que el cáncer de ovario se origina a partir de lesiones precursoras en las fimbrias de las trompas de Falopio. Objetivo: Determinar el nivel de conocimiento de los ginecólogos sobre la salpingectomía bilateral oportunista. Métodos: Se envió una encuesta por vía electrónica a médicos ginecólogos y residentes de Ginecología. Se incluyeron características demográficas, así como preguntas de interés relacionadas con la práctica clínica y la indicación de cirugía. Resultados: Se incluyeron 52 sujetos, 21 mujeres y 31 hombres, con una edad media de 40,7 años. Treinta y cinco ginecólogos certificados, así como 17 residentes de ginecología, se incluyeron como parte del grupo total. Treinta y seis individuos (69,2%) informaron haber realizado salpingectomía electiva. La motivación que tuvieron para realizar la salpingectomía como método de esterilización fue: «reducción del riesgo de cáncer de ovario en el futuro» (55,6%). La indicación de salpingectomía electiva mientras se realizaban otros procedimientos fue: «para prevenir el cáncer de ovario» (61,1%). Los ginecólogos certificados (42,9%) y los residentes (41,1%) consideraron la «detección con ultrasonido transvaginal» como el mejor método de prevención primaria para el cáncer de ovario en mujeres de bajo riesgo. Conclusiones: Cuando entrevistamos a los ginecólogos detectamos poca aceptación de la salpingectomía bilateral oportunista en México. Se debe diseñar una estrategia de formación en la residencia de Ginecología para motivar la prevención del cáncer de ovario.(AU)

Influence of shell thickness on the thermal stability and melting-like behavior of Al@Fe core-shell nanoparticles from atomistic simulations: a structural and dynamic description.

Core-shell nanoparticles (CSNPs) are a class of functional materials that have received important attention nowadays due to their adjustable properties by a controlled tuning of the core or shell. Understanding the thermal response and structural properties of these CSNPs is relevant to carrying out an analysis regarding their synthesis and application at the nanoscale. The present work is aimed to investigate the shell thickness effect on thermal stability and melting behavior of Al@Fe CSNPs by using molecular dynamics simulations. The results are discussed considering the influence of the Fe shell on the Al nanoparticle and analyzing the effect of different shell thicknesses in Al@Fe CSNPs. In general, calorific curves show a smooth energy decline for temperatures greater than room temperature for different shell thicknesses and sizes, corresponding to the inward and outward atomic movement of Al and Fe atoms, respectively, that produce a mixed Al-Fe nanoalloy. Here, the thermal stability of the Al@Fe nanoparticle is gradually lost passing to a liquid-Al@solid-Fe configuration and reaching a mixed Al-Fe state by an exothermic mechanism. Combining quantities of the atomic diffusion and structural identification, a stepped structural transition of the system is subsequently observed, where the melting-like point was estimated. Furthermore, it is observed that the Al@Fe CSNPs with greater stability are obtained with a thick shell and a large size. The ability to control shell thickness and vary the size opens up attractive opportunities to synthesize a broad range of new materials with tunable catalytic properties.

High-Resolution Transcriptomic Landscape of the Human Submandibular Gland.

Saliva-secreting and transporting cells are part of the complex cellular milieu of the human salivary gland, where they play important roles in normal glandular physiology and diseased states. However, comprehensive molecular characterization, particularly at single-cell resolution, is still incomplete, in part due to difficulty in procuring normal human tissues. Here, we perform an in-depth analysis of male and female adult human submandibular gland (SMG) samples by bulk RNA sequencing (RNA-seq) and examine the molecular underpinnings of the heterogeneous cell populations by single-cell (sc) RNA-seq. Our results from scRNA-seq highlight the remarkable diversity of clusters of epithelial and nonepithelial cells that reside in the SMG that is also faithfully recapitulated by deconvolution of the bulk-RNA data sets. Our analyses reveal complex transcriptomic heterogeneity within both the ductal and acinar subpopulations and identify atypical SMG cell types, such as mucoacinar cells that are unique to humans and ionocytes that have been recently described in the mouse. We use CellChat to explore ligand-receptor interactome predictions that likely mediate crucial cell-cell communications between the various cell clusters. Finally, we apply a trajectory inference method to investigate specific cellular branching points and topology that offers insights into the dynamic and complex differentiation process of the adult SMG. The data sets and the analyses herein comprise an extensive wealth of high-resolution information and a valuable resource for a deeper mechanistic understanding of human SMG biology and pathophysiology.

Fermentation conditions for yeast selection and effect of yeast-bacterial interaction in developing a starter culture for tequila fermentation.

Similar to other beverages, tequila fermentation can be improved using selected native strains. During fermentation, yeast and bacteria frequently act together and can improve product quality. However, their influence during tequila fermentation is not fully understood. Three Saccharomyces cerevisiae strains isolated in a previous study were used to determine their fermentation parameters. Fermentation of agave juice by a selected yeast strain in the presence of seven native bacterial species (individually and in consortium) was also evaluated. Optimal temperature, initial fructose, and pH were determined using a rotatory central composite design, and concomitant fermentative parameters were used to select the best tequila yeast strain. The yeast strain Teq-199 presented the best fructose consumption (91.0%), ethanol production (33.5 g/L), and yield (72%), as well as produced low concentrations of acetic acid (0.2 g/L). The optimal fermentation temperature was 32°C, similar to that used at distilleries. During fermentation of agave juice by strain Teq-199 in the presence of individual native bacteria, the yeast dominated fermentation, while bacterial species impaired its quality due to lactic acid production (>3.3 g/L). In the presence of a bacterial consortium, strain Teq-199 also dominated fermentation; however, a high concentration of acetic acid (6.5 g/L) was generated, reducing the quality of the fermentation parameters. A comparison with a commercial wine strain K1-V1116, revealed that the strain Teq-199 exhibited the best fermentation parameters, indicating its potential use as an inoculant in industrial processing. Since bacteria were detrimental, distilleries should exert efforts to reduce their impact. PRACTICAL APPLICATION: The optimal fermentation conditions for pre-selected yeast strains isolated during tequila production were determined, which led to the selection of the best-adapted yeast strain to fulfill the actual requirements and conditions in the tequila industry. This study allows the selection of yeast strains that could be used by local producers. In addition, this yeast was able to overcome a well-adapted bacterial consortium, showing dominance throughout the fermentation process. This study is unique since it explored bacterial interactions during fermentation process and proposes a method to assess the effect of these concomitant microorganisms to properly select and design a starter culture.

Rendimiento del ASAS Health Index en pacientes con Espondiloartritis de la vida real / Performance of ASAS Health Index in real life spondyloarthritis patients

Introducción: El cuestionario "Assessment of Spondyloarthritis International Society Health Index" (ASAS-HI) fue desarrollado para medir de manera global la funcionalidad y el estado de salud en pacientes con espondiloartritis (EspA). Se han propuesto puntos de corte para determinar diferentes estados de salud que fueron poco evaluados en pacientes de la vida real. Objetivos: Describir el estado de salud medido por ASAS-HI en pacientes argentinos con EspA axial (EspAax) y periférica (EspAp) en la práctica diaria y evaluar los factores asociados al pobre estado de salud. Materiales y métodos: Estudio de corte transversal, analítico y multicéntrico. Se incluyeron consecutivamente pacientes con EspAax y EspAp según criterios ASAS, de 15 centros argentinos. Análisis estadístico: Se realizó estadística descriptiva, análisis bivariado y multivariado (regresión logística múltiple) para evaluar los factores asociados al pobre estado de salud (ASAS-HI ≥12). Para analizar la validez de constructo de la herramienta se realizó correlación de Spearman entre el ASAS-HI y otros parámetros de evaluación de la enfermedad. Resultados: Se incluyeron 274 pacientes con EspA, con una edad media de 49 (±14) años y una duración mediana de la enfermedad de 62 meses (p25-75: 24-135), 155 (56,6%) de los pacientes eran de sexo masculino, 129 pacientes (47%) con EspAax y 145 (52,9%) EspAp. Según el ASAS-HI 119 pacientes (43,4%) presentaban buen estado de salud, 117 (42,7%) tenían estado de salud moderado y 38 (13.9%) pobre estado de salud. En los pacientes con EspAp el valor de ASAS-HI mediano fue de 7 (p25-75: 3-10). El ASAS-HI correlacionó positivamente con: DAS28: rho: 0.5 (p<0.001) y HAQ: rho: 0.54 (p<0.001). La variable asociada de manera independiente con pobre estado de salud fue el DAS28 (OR: 1.9, IC95% 1.1-3.4, p: 0.029). En los pacientes con EspAax el valor de ASAS-HI mediano fue de 6 (p25-75: 2.75-10). El ASAS-HI mostró correlación con: BASDAI: rho: 0.7 (p<0.001), ASDAS-ERS: rho: 0.7 (p<0,001), ASQoL: rho: 0.8 (p<0.001), BASFI rho: 0.75 (p<0.001). La variable que se asoció de manera independiente a pobre estado de salud fue el ASDAS-ERS (OR 6.6, IC95% 2-22, p 0.002). Conclusión: Un pobre estado de salud se asoció independientemente a mayor actividad de la enfermedad en pacientes con EspAax y EspAp. El ASAS-HI correlacionó con otros parámetros de la enfermedad, lo que refuerza la validez de constructo de esta nueva herramienta.

Introduction: The "Assessment of Spondyloarthritis International Society Health Index" (ASAS-HI) questionnaire was developed to globally measure function and health status in patients with spondyloarthritis (SpA). Cut-off points have been proposed to determine different health states that were poorly evaluated in real-life patients. Objectives: To describe the health status measured by ASAS-HI in Argentine patients with axial SpA (AxSpA) and peripheral SpA (SpAp) in daily practice and to evaluate the factors associated with poor health. Materials and methods: Cross-sectional, analytical and multicenter study. Patients with SpAax and SpAp were consecutively included according to ASAS criteria, from 15 Argentine centers. Statistical analysis: Descriptive statistics, bivariate and multivariate analysis (multiple logistic regression) were performed to evaluate the factors associated with poor health status (ASAS-HI ≥12). To analyze the construct validity of the tool, Spearman correlation was performed between the ASAS-HI and other disease evaluation parameters. Results: 274 patients with SpA were included, with a mean age of 49 (± 14) years and a median duration of the disease of 62 months (p25-75: 24-135), 155 (56.6%) were male, 129 patients (47%) with AxSpA and 145 (52.9%) SpAp. According to the ASAS-HI, 119 patients (43.4%) had good health, 117 (42.7%) had moderate health and 38 (13.9%) had poor health. In patients with SpAp, the mean ASAS-HI value was 7 (p25-75: 3-10). The ASAS-HI positively correlated with: DAS28: rho: 0.5 (p <0.001) and HAQ: rho: 0.54 (p <0.001). The variable independently associated with poor health status was DAS28 (OR: 1.9, 95% CI 1.1-3.4, p: 0.029). In patients with AxSpA, the mean ASAS-HI value was 6 (p25-75: 2.75-10). The ASAS-HI showed correlation with: BASDAI: rho: 0.7 (p <0.001), ASDAS-ERS: rho: 0.7 (p <0.001), ASQoL: rho: 0.8 (p <0.001), BASFI rho: 0.75 (p <0.001). The variable that was independently associated with poor health was the ASDAS-ERS (OR 6.6, 95% CI 2-22, p 0.002). Conclusion: Poor health status was independently associated with higher disease activity in patients with AxSpA and SpAp. The ASAS-HI correlated with other parameters of the disease, which reinforces the construct validity of this new tool.

Correlated flickering of erythrocytes membrane observed with dual time resolved membrane fluctuation spectroscopy under different D-glucose concentrations.

A correlated human red blood cell membrane fluctuation dependent on D-glucose concentration was found with dual time resolved membrane fluctuation spectroscopy (D-TRMFS). This new technique is a modified version of the dual optical tweezers method that has been adapted to measure the mechanical properties of red blood cells (RBCs) at distant membrane points simultaneously, enabling correlation analysis. Mechanical parameters under different D-glucose concentrations were obtained from direct membrane flickering measurements, complemented with membrane fluidity measurements using Laurdan Generalized Polarization (GP) Microscopy. Our results show an increase in the fluctuation amplitude of the lipid bilayer, and a decline in tension value, bending modulus and fluidity as D-glucose concentration increases. Metabolic mechanisms are proposed as explanations for the results.

The unfinished work of neonatal very low birthweight infants quality improvement: Improving outcomes at a continental level in South America.

Neonatal mortality rate varies between 4.2 and 18.6 per thousand by country in South America. There is little information regarding the outcomes of very low birth weight infants in the region and mortality rates are extremely variable ranging from 6% to over 50%. This group may represent up to 50-70% of the neonatal mortality and approximately 25-30% of infant mortality. Some initiatives, like the NEOCOSUR Network, have systematically collected and analyzed epidemiological information on VLBW infants' outcomes in the region. Over a 16-year period, survival without major morbidity improved from 37 to 44%. However, mortality has remained almost unchanged at approximately 27%, despite an increase in the implementation of the best available evidence in perinatal practices over time. Implementing quality improvement initiatives in the continent is particularly challenging but represents a great opportunity considering that there is a wide margin for progress in both care and outcomes.

Structural properties and thermal stability of multi-walled black phosphorene nanotubes and their operation as temperature driven nanorotors.

In this paper, we explore the influence of structural properties, thermal stability, and temperature on the rotational frequency of (0,n) armchair multi-walled black phosphorene nanotubes (MWßPNTs). Using Density Functional Theory (DFT) calculations, we first determine the influence of the outer wall rotation on the structural stability of (0,12)@(0,19) DWßPNTs, and (0,12)@(0,19)@(0,26) TWßPNTs. The results indicate that the relative energies of the DW- and the TWßPNTs do not change with the rotation angle. Therefore, the outer wall rotation is not important for the structural formation of the MWßPNTs. Then, using molecular dynamics (MD) simulations, we study the structural properties, thermal stability, and rotational frequency of (0,12)@(0,19) DWßPNTs, (0,12)@(0,19)@(0,26) TWßPNTs, and (0,12)@(0,19)@(0,26)@(0,33) QWßPNTs from 1 K to 400 K. The calorific curve, the mean-squared displacement, and the radial distribution function are analyzed to characterize the temperature behavior of the MWßPNTs. In all cases, the nanotubes are rotating: they act as thermal-driven rotors as the temperature increases, with a maximum rotational frequency of 16.7 GHz (clockwise direction) at 5 K for the DWßPNTs. Our results suggest that MWßPNTs could be used to construct room temperature nanomotors.

Process integration for emerging challenges: optimal allocation of antivirals under resource constraints.

Abstract: The global scientific community has intensified efforts to develop, test, and commercialize pharmaceutical products to deal with the COVID-19 pandemic. Trials for both antivirals and vaccines are in progress; candidates include existing repurposed drugs that were originally developed for other ailments. Once these are shown to be effective, their production will need to be ramped up rapidly to keep pace with the growing demand as the pandemic progresses. It is highly likely that the drugs will be in short supply in the interim, which leaves policymakers and medical personnel with the difficult task of determining how to allocate them. Under such conditions, mathematical models can provide valuable decision support. In particular, useful models can be derived from process integration techniques that deal with tight resource constraints. In this paper, a linear programming model is developed to determine the optimal allocation of COVID-19 drugs that minimizes patient fatalities, taking into account additional hospital capacity constraints. Two hypothetical case studies are solved to illustrate the computational capability of the model, which can generate an allocation plan with outcomes that are superior to simple ad hoc allocation.

Yeast and bacterial diversity, dynamics and fermentative kinetics during small-scale tequila spontaneous fermentation.

The study of microbial communities associated with spontaneous fermentation of agave juice for tequila production is required to develop starter cultures that improve both yield and quality of the final product. Quantification by HPLC of primary metabolites produced during the fermentations was determined. A polyphasic approach using plate count, isolation and identification of microorganisms, denaturing gradient gel electrophoresis and next generation sequencing was carried out to describe the diversity and dynamics of yeasts and bacteria during small-scale spontaneous fermentations of agave juice from two-year samplings. High heterogeneity in microbial populations and fermentation parameters were observed, with bacteria showing higher diversity than yeast. The core microorganisms identified were Saccharomyces cerevisiae and Lactobacillus fermentum. Practices in tequila production changed during the two-year period, which affected microbial community structure and the time to end fermentation. Bacterial growth and concomitant lactic acid production were associated with low ethanol production, thus bacteria could be defined as contaminants in tequila fermentation and efforts to control them should be implemented.

A platform to understand amyotrophic lateral sclerosis (ALS) and extend human motor neurons longevity / Plataforma para empezar a comprender la esclerosis lateral amiotrófica (ELA) y extender la longevidad de neuronas motoras humanas

In vitro modeling of neurodegenerative diseases is now possible by using patient-derived induced pluripotent stem cells (iPS). Through them, it is nowadays conceivable to obtain human neurons and glia, and study diseases cellular and molecular mechanisms, an attribute that was previously unavailable to any human condition. Amyotrophic lateral sclerosis (ALS) is one of the diseases that has gained a rapid advance with iPS technology. By differentiating motor neurons from iPS cells of ALS- patients, we are studying the mechanisms underlying ALS- disease onset and progression. Here, we introduce a cellular platform to help maintain longevity of ALS iPS-motor neurons, a cellular feature relevant for most late-onset human diseases. Long term cultures of patient-derived iPS cells might prove to be critical for the development of personalized-drugs.

Actualmente es posible modelar in vitro enfermedades neurodegenerativas humanas mediante el uso de células madre pluripotentes inducidas (iPS) derivadas del paciente. A través de ellas, es hoy concebible obtener neuronas y glía humanas, y estudiar mecanismos celulares y moleculares de enfermedades, un atributo que anteriormente no era posible para ninguna condición humana. La esclerosis lateral amiotrófica (ELA) es una de las enfermedades que se ha beneficiado con la tecnología de iPS. Al diferenciar neuronas motoras de células iPS obtenidas de pacientes con ELA, hemos iniciado estudios sobre los mecanismos que subyacen a la aparición y progresión de la enfermedad. Aquí, presentamos el desarrollo de una plataforma celular que permite extender la longevidad de las neuronas motoras derivadas de iPS, una característica relevante para la mayoría de las enfermedades humanas de inicio tardío. Los cultivos a largo plazo de células iPS provenientes de pacientes pueden ser determinantes en el desarrollo de terapias asociadas a la medicina de precisión.

Is eating wild rainbow trout safe? The effects of different land-uses on heavy metals content in Chile.

Cu, Mn, Fe, Zn, Cd and Pb levels were measured in liver and muscle samples of Rainbow Trout Oncorhynchus mykiss collected from three watersheds with different land-uses: native forest, exotic plantation, and agriculture in Chile, during January, April, July, and October 2012. Cd and Pb levels were not detected in the liver and muscle, probably since they are under the detection limits. Higher metal concentrations (liver-muscle tissues) were detected in samples from agriculture and exotic plantation streams, whereas trout from native forest streams had lower metal concentrations. Higher metal concentrations were detected in liver tissue compared to muscle tissue, and both negatively correlated to the length and weight of the fish. This suggest the liver had higher ability to accumulate Cu, Mn, Fe and Zn compared to muscle tissue. The concentration range of Fe and Zn recorded in the muscle are within the range reported by other authors, whereas Mn and Cu concentrations are higher than reported in the literature. However, at all sites the concentration of selected metals were below the limits permitted by current legislation (FAO), and therefore did not put the human population at risk, suggesting that is eating wild rainbow trout safe in Chile.

Origin, distribution, and geochemistry of arsenic in the Altiplano-Puna plateau of Argentina, Bolivia, Chile, and Perú.

Elevated concentrations of arsenic in water supplies represent a worldwide health concern. In at least 14 countries of South America, high levels have been detected relative to international standards and guidelines. Within these countries, the high plateau referred to as the "Altiplano-Puna", encompassing areas of Argentina, Bolivia, Chile, and Perú, exhibits high arsenic concentrations that could be affecting 3 million inhabitants. The origins of arsenic in the Altiplano-Puna plateau are diverse and are mainly natural in origin. Of the natural sources, the most important correspond to mineral deposits, brines, hot springs, and volcanic rocks, whereas anthropogenic sources are related to mining activities and the release of acid mine drainage (AMD). Arsenic is found in all water types of the Altiplano-Puna plateau over a wide range of concentrations (0.01 mg·L-1 < As in water > 10 mg·L-1) which in decreasing order correspond to: AMD, brines, saline waters, hot springs, rivers affected by AMD, rivers and lakes, and groundwater. Despite the few studies which report As speciation, this metalloid appears mostly in its oxidized form (As[V]) and its mobility is highly susceptible to the influence of dry and wet seasons. Once arsenic is released from its natural sources, it also precipitates in secondary minerals where it is generally stable in the form of saline precipitates and Fe oxides. In relation to human health, arsenic adaptation has been detected in some aboriginal communities of the Puna together with an efficient metabolism of this metalloid. Also, the inefficient methylation of inorganic As in women of the Altiplano might lead to adverse health effects such as cancer. Despite the health risks of living in this arsenic-rich environment with limited water resources, not all of the Altiplano-Puna is properly characterized and there exists a lack of information regarding the basic geochemistry of arsenic in the region.

Effect of the earthquake-tsunami (Chile, 2010) on toxic metal content in the Chilean abalone mollusc Concholepas concholepas.

Toxic metal content were measured in samples of mollusc Concholepas concholepas obtained from the Chilean coast. Samples were collected during two periods, one before and one after the earthquake-tsunami which occurred in the Maule Region, Chile, February 27th, 2010 as a result of an earthquake with a magnitude of 8.8. Quantification of toxic metals in samples of hepatopancreas and muscle tissue was performed using flame atomic absorption spectroscopy. The analytical methodology was validated with certified reference material. The content means measured in muscle tissue for January 2010 were Cu: 10.3; Cr: 0.7; Cd: < 0.1; Mn: 3.6 and Zn: 38.6 µg g-1 (dry weight). For October 2014, the means were Cu: 8; Cr: 2.4; Cd: < 0.1; Mn: 5.6 and Zn: 45.4 µg g-1 (dry weight). In hepatopancreas tissue, the content means were Cu: 14.8; Cr: 2.4; Cd: 246.2; Mn: 4.4 and Zn: 1552.9 µg g-1 (dry weight). For October 2014, the means were Cu: 53.7; Cr: 3.5; Cd: 118; Mn: 13.4 and Zn: 1352.3 µg g-1 (dry weight). Cd, Cr, Cu, Mn and Zn content in the samples of hepatopancreas were generally higher than those recorded in muscle tissue however they were not always statistically significant. Statistical analysis showed that Cu and Mn content in the post-tsunami period increased in the hepatopancreas tissue. The concentrations of Cd, Cr, Cu, Mn, and Zn measured in the muscular tissue (edible part) of the species Conchalepas concholepas, were lower than the maximum contents allowed by the current legislation (FAO/WHO, 2004; EU, 2001) and its consumption is not a risk to human health.

Enological Qualities and Interactions Between Native Yeast and Lactic Acid Bacteria from Queretaro, Mexico.

Despite the importance of strain compatibility, most of the enological strain selection studies are carried out separately on yeasts and lactic acid bacteria (LAB). In this study, the enological traits and interactions between native yeasts and LAB were studied. The H2 S and acetic acid production, growth rates at 8 °C, killer phenotypes, flocculation, and tolerance to must and wine inhibitors were determined for 25 Saccharomyces yeasts. The ability to grow under two wine-like conditions was also determined in 37 LAB (Oenococcus oeni and Lactobacillus plantarum). The yeast-LAB compatibility of selected strains was tested in a sequential scheme. Finally, microvinification trials were performed using two strains from each group to determine the efficiencies and quality parameters. The phenotypic characterization by the K-means and hierarchical clusters indicated a correlation between flocculation and optical density increase in simulated must and wine medium (r = -0.415) and grouped the prominent yeasts SR19, SR26, and N05 as moderately flocculent, killer, acid producing, and highly tolerant strains. Among the LAB, L. plantarum FU39 grew 230% more than the rest. With regard to interactions, LAB growth stimulation (14-fold on average) due to the previous action of yeasts, particularly of SR19, was observed. The final quality of all wines was similar, but yeast SR19 performed a faster and more efficient fermentation than did N05, Also L. plantarum FU39 fermented faster than did O. oeni VC32. The use of quantitative data, and multivariate analyses allowed an integrative approach to the selection of a compatible and efficient pair of enological yeast-LAB strains. PRACTICAL APPLICATION: An alternative scheme is proposed for the joint selection of yeast and lactic acid bacteria strains, which allows us to foresee the interactions that may occur between them during winemaking. The kinetic parameters, turbidimetrically measured and analyzed by multivariate methods, simplify the detection of outstanding selectable microorganisms. This methodology can be implemented at any cellar or even any fermentative industry that aims to select compatible yeast and lactic acid bacteria.

Geology and geochemistry of the Atacama Desert.

The Atacama Desert, the driest of its kind on Earth, hosts a number of unique geological and geochemical features that make it unlike any other environment on the planet. Considering its location on the western border of South America, between 17 and 28 °S, its climate has been characterized as arid to hyperarid for at least the past 10 million years. Notably dry climatic conditions of the Atacama Desert have been related to uplift of the Andes and are believed to have played an important role in the development of the most distinctive features of this desert, including: (i) nitrates and iodine deposits in the Central Depression, (ii) secondary enrichment in porphyry copper deposits in the Precordillera, (iii) Li enrichment in salt flats of the Altiplano, and (iv) life in extreme habitats. The geology and physiography of the Atacama Desert have been largely shaped by the convergent margin present since the Mesozoic era. The geochemistry of surface materials is related to rock geochemistry (Co, Cr, Fe, Mn, V, and Zn), salt flats, and evaporite compositions in endorheic basins (As, B, and Li), in addition to anthropogenic activities (Cu, Mo, and Pb). The composition of surface water is highly variable, nonetheless in general it presents a circumneutral pH with higher conductivity and total dissolved solids in brines. Major water constituents, with the exception of HCO3-, are generally related to the increase of salinity, and despite the fact that trace elements are not well-documented, surface waters of the Atacama Desert are enriched in As, B, and Li when compared to the average respective concentrations in rivers worldwide.

Selection of Yeast Strains for Tequila Fermentation Based on Growth Dynamics in Combined Fructose and Ethanol Media.

The high concentration of fructose in agave juice has been associated with reduced ethanol tolerance of commercial yeasts used for tequila production and low fermentation yields. The selection of autochthonous strains, which are better adapted to agave juice, could improve the process. In this study, a 2-step selection process of yeasts isolated from spontaneous fermentations for tequila production was carried out based on analysis of the growth dynamics in combined conditions of high fructose and ethanol. First, yeast isolates (605) were screened to identify strains tolerant to high fructose (20%) and to ethanol (10%), yielding 89 isolates able to grow in both conditions. From the 89 isolates, the growth curves under 8 treatments of combined fructose (from 20% to 5%) and ethanol (from 0% to 10%) were obtained, and the kinetic parameters were analyzed with principal component analysis and k-means clustering. The resulting yeast strain groups corresponded to the fast, medium and slow growers. A second clustering of only the fast growers led to the selection of 3 Saccharomyces strains (199, 230, 231) that were able to grow rapidly in 4 out of the 8 conditions evaluated. This methodology differentiated strains phenotypically and could be further used for strain selection in other processes. PRACTICAL APPLICATION: A method to select yeast strains for fermentation taking into account the natural differences of yeast isolates. This methodology is based on the cell exposition to combinations of sugar and ethanol, which are the most important stress factors in fermentation. This strategy will help to identify the most tolerant strain that could improve ethanol yield and reduce fermentation time.

Stallion spermatozoa surviving freezing and thawing experience membrane depolarization and increased intracellular Na.

In order to gain insight of the modifications that freezing and thawing cause to the surviving population of spermatozoa, changes in the potential of the plasma membrane (Em) and intracellular Na+ content of stallion spermatozoa were investigated using flow cytometry. Moreover, caspase 3 activity was also investigated and the functionality of the Na+ -K+ ATPase pump was investigated before and after freezing and thawing. Cryopreservation caused a significant (p < 0.001) increase in the subpopulation of spermatozoa with depolarized sperm membranes, concomitantly with an increase (p < 0.05) in intracellular Na+ . These changes occurred in relation to activation of caspase 3 (p < 0.001). Cryopreservation reduced the activity of the Na-K+ pump and inhibition of the Na+ -K+ ATPase pump with ouabain-induced caspase 3 activation. It is concluded that inactivation of Na+ -K+ ATPase occurs during cryopreservation, an inhibition that could play a role explaining the accelerated senescence of the surviving population of spermatozoa.