Efecto espaciotemporal en las propiedades fisicoquímicas del agar nativo de Gracilaria parvispora (Rhodophyta) en el Pacífico Mexicano Tropical (Oaxaca-Chiapas)

Background: Gracilaria parvispora is an invasive red seaweed located in coastal lagoons along the Tropical Mexican Pacific. Gracilaria species are the main source of agar around the world. Goals: Spatial and seasonal trends of the properties of native agar from the invasive seaweed G. parvispora were determined in three localities in the states of Oaxaca and Chiapas belonging to coastal lagoons along the Tropical Mexican Pacific: Ballenato, Paredón, and San Vicente. Methods: Native agar was obtained from dry samples of seaweed and the agar yield, gel strength, melting and gelling temperatures, hysteresis, and sulfate and 3,6-anhydrogalactose content were determined for each sample. Moreover, the polysaccharide structures and the location of sulfate groups in agar samples were identified. Results: The phycocolloid is a polysaccharide agar type. The agar yield was significantly different between seasons and localities, with the highest values during the dry season (19.9 ± 0.004 %) at Paredón (20.6 ± 0.01 %). Gel strength, melting temperature and gel hysteresis showed significant spatial differences; the highest values were obtained in Ballenato (367.3 ± 14.2 g cm−2, 80.2 ± 1.4 °C, 44.3 ± 2.2 °C, respectively); gelling temperature did not show significant differences between localities or seasons. Chemical properties were significantly different between seasons: 3,6-anhydrogalactose content was higher during the dry season (36.2 ± 0.2 %), and sulfate content was higher during the rainy season (12.69 ± 0.21 %). Salinity was significantly different between seasons, and the highest was obtained during the dry season (38.7 ± 0.1). Surface water temperature varied between localities, and the highest mean value was recorded at Paredón (32.5 ± 0.2 °C). Conclusions: The chemical properties of the G. parvispora native agar were lower than the standards for food and industrial use.Antecedentes: Gracilaria parvispora es un alga roja invasora que se encuentra en lagunas costeras del Pacífico Mexicano Tropical. A nivel mundial, las especies de Gracilaria son la fuente principal de agar. Objetivos: Se determinaron las tendencias espaciales y temporales de las propiedades del agar nativo de G. parvispora en tres localidades de los estados de Oaxaca y Chiapas, pertenecientes a lagunas costeras del Pacífico Mexicano Tropical: Ballenato, Paredón y San Vicente. Métodos: Se determinó el rendimiento del agar, la fuerza de gel, la temperatura de fusión y gelificación, la histéresis, y el contenido de sulfatos y 3,6-anhidrogalactosa del agar nativo obtenido de muestras secas de macroalga. Además, se identificaron las estructuras de los polisacáridos y la posición de los grupos sulfato en las muestras. Resultados: El ficocoloide es un polisacárido tipo agar. El rendimiento mostró diferencias significativas entre localidades y temporadas, con valores mayores durante la temporada de secas (19.9 ± 0.004 %) y en Paredón (20.6 ± 0.01 %). La fuerza de gel, la temperatura de fusión y la histéresis mostraron diferencias espaciales significativas; con valores más altos para las muestras de Ballenato (367.3 ± 14.2 g cm-2, 80.2 ± 1.4 °C, 44.3 ± 2.2 °C, respectivamente); la temperatura de gelificación no mostró diferencias significativas entre localidades o temporadas. Las propiedades químicas mostraron diferencias significativas entre temporadas: el contenido de 3,6-anhidrogalactosa fue mayor durante la temporada de secas (36.2 ± 0.2 %), y el contenido de sulfato fue mayor durante la temporada de lluvias (12.69 ± 0.21 %). La salinidad fue significativamente diferente entre temporadas, con mayor valor para la temporada de secas (38.7 ± 0.1). La temperatura superficial del agua varió entre localidades, la más alta se registró en Paredón (32.5 ± 0.2 °C). Conclusiones: Las propiedades químicas de G. parvispora fueron menores a los estándares para su uso industrial y alimenticio

Are medium cut-off membranes the future, or the promising reality for chronic hemodialysis patients?

The development of hemodialysis (HD) membranes has substantially advanced in the last decade. This has resulted in the manufacturing of medium cut-off membranes (MCO) whose internal architecture is based on greater pore size and a smaller diameter, thus promoting the clearance of particles of greater size as well as retrofiltration. Multiple studies have proven their efficacy in the clearance of uremic mid-sized molecules such as B2-microglobulin, free light chains, and some interleukins; this clearance is far superior with MCO membranes when compared with high-flux HD, and similar to that obtained with online hemodiafiltration. This review summarizes the results of the most relevant clinical studies of this membrane in terms of uremic toxin clearance, as well as the features of some clinical outcomes such as quality of life and hospitalizations

Efecto de fucoidan y alginato en la germinación y el crecimiento de plántulas de frijol mungo: Fucoidan and alginate on mung bean growth

Background. The interest in studying seaweed polysaccharides as plant growth biostimulants is recent and has generally focused on seaweed liquid extracts for compounds content that have positive effect on plant development. Within these compounds are the carbohydrates such as alginate and fucoidan, among others. Goals. To evaluate the effect of crude fucoidan and alginate on seed germination and their growth-stimulating activity on seedling of mung bean (Vigna radiata). Methods. Fucoidan and alginate from Eisenia arborea and Sargassum horridum at six different doses (0.6, 1.2, 2.5, 5, 10, and 20 mg m‒1 ) were evaluated on seed germination and seedling growth of mung bean. Results. Alginate from both algae species in this study did not show a significant effect on mung bean growth. Fucoidan from S. horridum produced the significant effect on mung bean growth by increasing root length (16.2%) and seedling total length (11.9%) at a concentration of 0.6 mg mL‒1 and an increase in the dry weight of the seedling (31%) at a concentration of 20 mg mL‒1 . While fucoidan from E. arborea had the higher effect on shoot growth (10.5%) and total length (10.7%), compared to the control when applied at a concentration of 10 mg mL‒1 . Conclusions. Overall, this study showed that fucoidan from both S. horridum and E. arborea can stimulate seedling growth and increase the germination percentage of mung bean seeds compared to the control.Antecedentes. El interés por estudiar los polisacáridos de algas marinas como bioestimulantes del crecimiento de las plantas es reciente, y generalmente se ha centrado en los extractos líquidos de algas marinas por su contenido de compuestos que tienen un efecto positivo en el desarrollo de plantas. Dentro de estos compuestos se encuentran carbohidratos como el alginato y el fucoidan, entre otros. Objetivos. Evaluar el efecto de fucoidan crudo y alginato en la germinación de semillas y su actividad estimulante del crecimiento en plántulas de frijol mungo (Vigna radiata). Métodos. Fucoidan y alginato de Eisenia arborea y Sargassum horridum fueron probadas a seis concentraciones diferentes (0.6, 1.2, 2.5, 5, 10 y 20 mg mL‒1 ) sobre la germinación de semillas y el crecimiento de plántulas de frijol mungo. Resultados. El alginato de ambas especies de algas de este estudio no mostró un efecto significativo sobre el crecimiento de frijol mungo. El fucoidan de S. horridum produjo el mayor efecto en el crecimiento del frijol mungo, incrementando la longitud de la raíz (16.2%) y la longitud total de la plántula (11.9%) a una concentración de 0.6 mg mL‒1 y un incremento en el peso seco de la plántula (31%) a una concentración de 20 mg mL‒1 . Mientras que el fucoidan de E. arborea tuvo el mayor efecto en el crecimiento de brotes (10.5%) y la longitud total (10.7%) en comparación con el control, cuando se aplica a una concentración de 10 mg mL‒1 . Conclusiones. En general, este estudio mostró que el fucoidan tanto de S. horridum como el de E. arborea puede estimular el crecimiento de plántulas y aumentar el porcentaje de germinación de semillas de frijol mungo en comparación con el control

Anticoagulant screening of marine algae from Mexico, and partial characterization of the active sulfated polysaccharide from Eisenia arborea

The in vitro anticoagulant activity of 41 water extracts of various seaweeds from Baja California Sur, Mexico was evaluated. In this study, nine extracts exhibited anticoagulant activity in the prothrombin time assay, and 29 extracts were active in the activated partial thromboplastin time assay. The water extract obtained at 25°C from the brown seaweed Eisenia arborea was the most active in both assays, increasing the normal blood clotting-time over 300 s at 100 mg mL-1. The fractionation of this extract by anion exchange chromatography yielded 3 fractions. Fraction 2 eluted with 1.0 M sodium chloride increased the clotting-time over 300 s in the activated partial thromboplastin time assay at 5 µg mL-1, being more active than sodium heparin. Chemical and spectroscopic analysis of fraction 2 showed to be a heterofucan sulfated composed by 56.2% ±0.1 of total sugars, and 45% of sulfates. The neutral sugar constituents of the active heterofucan was determined to be 47.6% flucose, 35.5% xylose and 16.9% thamnose, with substitution of sulfate groups at C-4 (axial), and minor substitutions at C-2 and-or C-3

Monthly variation in the chemical composition of Eisenia arborea J.E. Areschoug

The brown alga Eisenia arborea is the second most abundant brown alga along the western coast of the Baja California Peninsula of Mexico. Samples of E. arborea were collected in Bahía Asunción, BCS, over 10 months. Chemical composition was analyzed from dried alga (%, dw): moisture (10.34%), protein (9.44%), ash (24.77%), lipids (0.60%), fiber (5.22%), and carbohydrates (49%). Gross energy was 9.8 kJ g−1. Seven minerals were analyzed and the four most abundant were K, Na, Mg, and Ca, ranging from 907 to 7,946 mg.100 g−1. The concentrations of six vitamin levels were also determined: A, C, E, D3, B2, and B1. Seventeen amino acids were analyzed and the most abundant were glutamic acid, aspartic acid, and leucine. Total fatty acids ranged from 21 to 65 mg.100 g−1 (dw). Individua concentration were also determined for arachidonic acid, alpha linolenic acid, linoleic acid, eicosapentaenoic acid, and docosahexaenic acid. Sponins, cyanogenic glycosides, and alkaloids, were not detected. Our results suggest that E. arborea isa good candidate to be tested as supplement food animal, including human. It contains essential amino acid, is low in lipids and fiber, and could be a source of vitamins and minerals

Recomendaciones para la creación, cuidado y manejo de los accesos vasculares para hemodiálisis. Documento de Posición del Comité de Nefrología Intervencionista y del Grupo de Consenso para Optimización de Accesos Vasculares de la Sociedad Latinoamericana de Nefrología e Hipertensión

Este documento establece la posición del Comité de Nefrología Intervencionista y del Grupo de Consenso para Optimización de Accesos Vasculares de la Sociedad Latinoamericana de Nefrología e Hipertensión (SALNH) y es el resultado del interés promovido en la sociedad para diseñar un conjunto de recomendaciones, simples, exhaustivas y sobre todo aplicables a la región acerca de la creación, cuidado y manejo de los accesos vasculares para pacientes en hemodiálisis; para ello se seleccionó la información con mayor sustento científico y que mejor se adapta a las necesidades de los pacientes. Este documento intenta poner al alcance de todos los profesionales de la salud y los pacientes las mejores opciones sobre el acceso vascular (AV) para hemodiálisis, desde su planeación, creación y vigilancia hasta la resolución de las complicaciones potenciales