Potencial de la levadura oleaginosa Clavispora lusitaniae Hi2 en la conversión de residuos agroindustriales a lípidos / Capacity of the oleaginous yeast Clavispora lusitaniae Hi2 to transform agroindustrial residues into lipids

AntecedentesLos lípidos obtenidos de microorganismos oleaginosos a partir de hidrolizados de residuos lignocelulósicos son una alternativa para la fabricación de biodiesel.ObjetivosAislar una levadura oleaginosa capaz de producir lípidos a partir de nejayote centrifugado (NC), hidrolizado de sólidos de nejayote (HSN) e hidrolizado de bagazo de caña de azúcar (HBC).MétodosPara identificar los aislamientos recuperados se secuenció el ADN ribosómico 26S. La capacidad metabólica se evaluó mediante tiras API20C AUX. La caracterización nutricional del NC, HSN y HBC se realizó cuantificando azúcares reductores, carbohidratos totales, almidón, proteína y nitrógeno total. La capacidad de producción de biomasa y lípidos de la cepa Clavispora lusitaniae Hi2 se evaluó mediante cinéticas de crecimiento en medios de cultivo formulados a partir de NC, HSN y HBC.ResultadosSe aislaron e identificaron seis cepas de levaduras oleaginosas, siendo C. lusitaniae Hi2 seleccionada para producir lípidos mediante el uso de nejayote. Dicha cepa puede utilizar glucosa, xilosa, arabinosa, galactosa y celobiosa como fuentes de carbono. Los cultivos de C. lusitaniae Hi2 en medio con NC y HSN (en relación 25:75) presentaron la mayor producción de biomasa, 5,6 ± 0,28 g/L; la mayor producción de lípidos, 0,99±0,09 g/L, se obtuvo con una relación 50:50 de estos residuos a las 20 h de incubación.ConclusionesLa utilización de NC, HSN y HBC para el crecimiento de C. lusitaniae Hi2 es una opción para el aprovechamiento de estos residuos y la generación de compuestos de interés biotecnológico. (AU)

BackgroundSingle-cell oils obtained from oleaginous microorganisms by using lignocellulosic waste hydrolysates are an alternative for producing biodiesel.AimsTo isolate a yeast strain able to produce lipids from centrifuged nejayote (CN), hydrolyzed nejayote solids (HNS) and hydrolyzed sugarcane bagasse (HSB).MethodsIn order to identify the yeasts recovered, 26S ribosomal DNA was sequenced. The metabolic profile was assessed by using API20C AUX strips. The nutritional characterization of CN, HNS and HSB was performed by quantifying reducing sugars, total carbohydrates, starch, protein and total nitrogen. The biomass and lipid production ability were evaluated by performing growth kinetics of Clavispora lusitaniae Hi2 in combined culture media.ResultsSix oleaginous yeast strains were isolated and identified, selecting C. lusitaniae Hi2 to study its lipids production by using nejayote. The C. lusitaniae Hi2 strain can use glucose, xylose, arabinose, galactose and cellobiose as carbon sources. Cultures of C. lusitaniae Hi2 presented the best biomass (5.6±0.28 g/L) and lipid production (0.99±0.09 g/L) at 20 h of incubation with the CN:HNS media in the 25:75 and 50:50 ratios, respectively.ConclusionsThe use of CN, HNS and HSB for the growth of C. lusitaniae Hi2 is an option to take advantage of these agro-industrial residues and generate compounds of biotechnological interest. (AU)

El cigarrillo: dispositivo de ingeniería perfecto, pero no seguro. Es basura / The cigarette: a perfect, but not safe, engineering device. It is garbage

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Role of the antioxidant defense system during the production of lignocellulolytic enzymes by fungi

Fungi are used for the production of several compounds and the efficiency of biotechnological processes is directly related to the metabolic activity of these microorganisms. The reactions catalyzed by lignocellulolytic enzymes are oxidative and generate reactive oxygen species (ROS). Excess of ROS can cause serious damages to cells, including cell death. Thus, the objective of this work was to evaluate the lignocellulolytic enzymes produced by Pleurotus sajor-caju CCB020, Phanerochaete chrysosporium ATCC 28326, Trichoderma reesei RUT-C30, and Aspergillus niger IZ-9 grown in sugarcane bagasse and two yeast extract (YE) concentrations and characterize the antioxidant defense system of fungal cells by the activities of superoxide dismutase (SOD) and catalase (CAT). Pleurotus sajor-caju exhibited the highest activities of laccase and peroxidase in sugarcane bagasse with 2.6 g of YE and an increased activity of manganese peroxidase in sugarcane bagasse with 1.3 g of YE was observed. However, P. chrysosporium showed the highest activities of exoglucanase and endoglucanase in sugarcane bagasse with 1.3 g of YE. Lipid peroxidation and variations in SOD and CAT activities were observed during the production of lignocellulolytic enzymes and depending on the YE concentrations. The antioxidant defense system was induced in response to the oxidative stress caused by imbalances between the production and the detoxification of ROS

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Isolation and Characterization of Novel Lignolytic, Cellulolytic, and Hemicellulolytic Bacteria from Wood-Feeding Termite Cryptotermes brevis

In a natural ecosystem, various organisms digest and hydrolyze lignocellulose biomass efficiently. Termites are one of them. They digest lignocellulose biomass with the help of symbiotic microorganisms in their gut. Therefore, termites gut may harbor potential sources of microorganisms capable to degrade lignocellulose biomass. In this study, termite gut microbiomes of Cryptotermes brevis species were isolated and identified for their capability to degrade lignin and polysaccharides. Alkali lignin, carboxymethylcellulose, and xylan were used as the only carbon sources in the medium to isolate lignin-, cellulose-, and hemicellulose-degrading bacteria. By this method, two bacteria strains, Bacillus sp. BMP01 and Ochrobactrum oryzae BMP03 strain were isolated and identified. Bacillus sp. BMP01 strain has capabilities to hydrolyze carboxymethylcellulose and xylan to glucose and xylose, respectively. This strain showed high xylanase activity (about 0.21 U/ml) and carboxymethyl cellulase activity (about 0.25 U/ml). The ability to hydrolyze both carboxymethylcellulose and xylan makes it superior to other known cellulolytic bacteria. Ochrobactrum oryzae BMP03 strain showed laccase activity, which indicates its ability to depolymerize lignin. Lignocellulose-degrading bacteria play a vital role in the biological conversion of lignocellulose biomass to biofuel. Overall, this study shows that termite's gut microbiomes are potential sources of lignocellulose-degrading bacteria that can be cultured and used in the biological conversion of lignocellulose biomass to biofuel

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El triacetato de celulosa asimétrico es una alternativa segura y eficaz para la hemodiafiltración en línea / Asymmetric cellulose triacetate is a safe and effective alternative for online haemodiafiltration

ANTECEDENTES: En la hemodiafiltración posdilucional se han usado solo membranas sintéticas. Ahora contamos con un triacetato de celulosa asimétrico (ATA(R)) cuyas características lo hacen apto para esta técnica. OBJETIVOS: Describir las prestaciones y el comportamiento in vivo de esta membrana estudiando la eficacia depurativa y el uso clínico, además de su biocompatibilidad aguda tras un mes de tratamiento. MÉTODOS: Estudio prospectivo observacional en el que se incluyeron 23 pacientes que se dializaron durante 4 semanas con ATA(R) manteniendo su pauta previa. RESULTADOS: Se realizaron 287 sesiones y se recogieron 264 sesiones completas. Con un tiempo efectivo de 243,7 (17,6) min y un flujo medio de sangre de 371,7 (23) ml/min, se obtuvo un Kt medio de 56,3 (5,3) l, un volumen convectivo de 27,1 (4,2) l, con una fracción de filtración del 29,9 (3,7) %, un porcentaje de reducción (RR) de urea de 81 (5,2) %, un RR de creatinina de 74,7 (4,6) %, un RR de Beta2-microglobulina de 76,5 (4,8) % y un RR de proteína transportadora de retinol de 18,6 (7,6) %. No se produjeron problemas técnicos ni alarmas. No fue preciso cambiar la dosificación de heparina. A los 30 min de la sesión no se produjo ningún aumento de C3a, C5a ni leucopenia. Tampoco se modificaron de forma significativa las poblaciones monocitarias ni la IL-Beta1 ni IL-6 tras un mes de tratamiento. CONCLUSIONES: ATA(R) logra un Kt y un volumen convectivo adecuados, sin problemas técnicos y con buen perfil de biocompatibilidad e inflamatorio, lo que lo convierte en una posibilidad más de tratamiento para hemodiafiltración posdilucional, máxime en pacientes alérgicos a membranas sintéticas

BACKGROUND: In post-dilution haemodiafiltration only synthetic membranes have been used to date. Asymmetric cellulose triacetate (ATA(TM)) is now available, whose characteristics are suitable for this technique. OBJECTIVES: To describe the in vivo performance and behaviour of this membrane, to identify its depurative effectiveness, use in clinical practice and its biocompatibility, both acute and after one month of treatment. METHODS: Observational prospective study of 23 patients who were dialysed for 4 weeks using an ATA(TM) membrane and who maintained their prior regimen. RESULTS: A total of 287 sessions were performed and 264 complete sessions were collected. With an effective time of 243.7 (17.6) min and a mean blood flow of 371.7 (23) ml/min, an average Kt of 56.3 (5.3) l was observed, as well as a convection volume of 27.1 (4.2) l, a filtration fraction of 29.9 (3.7) %, a urea reduction ratio (RR) of 81 (5.2) %, a creatinine RR of 74.7 (4.6) %, a Beta2-microglobulin RR of 76.5 (4.8) % and a retinol binding protein RR of 18.6 (7.6) %. There were no technical problems or alarms. Changing the heparin dosage was not necessary. No increases in C3a or C5a concentrations or leukopenia were observed in the first 30min of the session. Neither the monocyte subpopulations nor IL-Beta1 or IL-6 were significantly altered after one month of treatment. CONCLUSIONS: The new ATA(TM) membrane achieves adequate Kt and convection volume, without technical problems and with good biocompatibility and inflammatory profiles. It is therefore a valid option for post-dilution haemodiafiltration, particularly in patients allergic to synthetic membranes

Mecanismos y regulación de la hidrólisis enzimática de celulosa en hongos filamentosos: casos clásicos y nuevos modelos / Mechanisms and regulation of enzymatic hydrolysis of cellulose in filamentous fungi: classical cases and new models

La celulosa es la fuente de carbono renovable más abundante de la Tierra. Sin embargo, la estructura de este polímero constituye una barrera física y química para acceder al carbono, lo que ha limitado el aprovechamiento del mismo. En la naturaleza, un pequeño porcentaje de microorganismos pueden degradarla a través de la expresión de celulasas. Dentro de estos microorganismos, uno de los grupos más activos y eficientes son los hongos filamentosos. Esta revisión describe las similitudes y diferencias de los mecanismos de acción de las celulasas y los mecanismos de regulación de su expresión para 3 de los modelos de hongos filamentosos celulolíticos más estudiados: Trichoderma reesei, Aspergillus niger y Aspergillus nidulans, y para un modelo recientemente descrito, Neurospora crassa. Se encontró que los mecanismos de acción enzimática son muy similares en todos los modelos estudiados, no así los mecanismos de regulación génica. Entender las particularidades de cada sistema es fundamental en el desarrollo de estrategias para la mejora de la producción de celulasas, ya sea proporcionando el ambiente óptimo (condiciones de fermentación) o aumentando la expresión en estos microorganismos mediante ingeniería genética (AU)

Cellulose is the most abundant renewable carbon source on earth. However, this polymer structure comprises a physical and chemical barrier for carbon access, which has limited its exploitation. In nature, only a few percentage of microorganisms may degrade this polymer by cellulase expression. Filamentous fungi are one of the most active and efficient groups among these microorganisms. This review describes similarities and differences between cellulase activity mechanisms and regulatory mechanisms controlling gene expression for 3 of the most studied cellulolytic filamentous fungi models: Trichoderma reesei, Aspergillus niger and Aspergillus nidulans, and the recently described model Neurospora crassa. Unlike gene expression mechanisms, it was found that enzymatic activity mechanisms are similar for all the studied models. Understanding the distinctive elements of each system is essential for the development of strategies for the improvement of cellulase production, either by providing the optimum environment (fermentation conditions) or increasing gene expression in these microorganisms by genetic engineering (AU)

Preliminary data on growth and enzymatic abilities of soil fungus Humicolopsis cephalosporioides at different incubation temperatures / Datos preliminares sobre el crecimiento y la capacidad enzimática del hongo de suelo Humicolopsis cephalosporioides a diferentes temperaturas de incubación

Background. Nothofagus pumilio (Poepp & Endl.) Krasser, known as 'lenga' is the most important timber wood species in southernmost Patagonia (Argentina). Humicolopsis cephalosporioides Cabral & Marchand is a soil fungus associated with Nothofagus pumilio forests, which has outstanding cellulolytic activity. However, there is no information about the ability of this fungus to use organic substrates other than cellulose, and its ability to produce different enzyme systems, as well as its response to temperature. Aims. The aim of this study was to examine the role of H. cephalosporioides in degradation processes in N. pumilio forests in detail by evaluating the in vitro ability of four isolates of this fungus to grow and produce different lytic enzyme systems, and their response to incubation temperature. Methods. The ability of the fungi to grow and produce enzyme systems was estimated by inoculating them on agar media with specific substrates, and the cultures were incubated at three temperatures. Results. A differential behavior of each strain in levels of growth and enzyme activity was found according to the medium type and/or incubation temperature. Conclusions. A intra-specific variability was found in H. cephalosporioides. Likewise a possible link between the saprotrophic role of this fungus in N. pumilio forests and the degradation of organic matter under stress conditions, such as those from frosty environments, was also discussed (AU)

Antecedentes. Nothofagus pumilio (Poepp & Endl) Krasser (N. pumilio), conocido como «lenga», es la especie maderable más importante en el extremo sur de Patagonia (Argentina). Humicolopsis cephalosporioides Cabral & Marchand es un hongo del suelo asociado a bosques de N. pumilio, que tiene una actividad celulolítica excepcional. Sin embargo, no hay información acerca de la capacidad de este hongo para utilizar otros sustratos orgánicos distintos de la celulosa, o para producir diferentes sistemas enzimáticos, así como su respuesta a la temperatura. Objetivos. El objetivo de este estudio fue profundizar en el rol que Humicolopsis cephalosporioides tiene en los procesos de degradación en los bosques de N. pumilio a través de la evaluación de la capacidad in vitro de 4 aislamientos de este hongo para crecer y producir diferentes sistemas enzimáticos líticos y su respuesta a la temperatura de incubación. Métodos. La capacidad de los hongos para crecer y producir sistemas enzimáticos se estimó a través de su inoculación sobre medios de agar con sustratos específicos, siendo incubados a 3 temperaturas. Resultados. Se observó un comportamiento diferencial de cada cepa en el crecimiento y la actividad enzimática de acuerdo con el tipo de medio o la temperatura de incubación. Conclusiones. Se observó variabilidad intraespecífica en Humicolopsis cephalosporioides. Asimismo, se discutió la posible relación entre el rol saprotrófico de este hongo en los bosques de N. pumilio y la degradación de la materia orgánica en condiciones estresantes, como las existentes en ambientes fríos (AU)

Rapidly disintegrating tablets of metoclopramide hydrochloride using novel chemically modified cellulose

The purpose of the study was to modify cellulose using hydrochloride salt of 2-aminoethanoyl chloride with optimum hydrophilic and hydrophobic properties to impart it a superdisintegrant activity and also to formulate and evaluate rapidly disintegrating tablets of metoclopramide hydrochloride using this novel chemically modified cellulose. A novel polymer, chemically modified cellulose was synthesized by chemically modifying microcrystalline cellulose with hydrochloride salt of 2-aminoethanoyl chloride. The formation of novel polymer was confirmed by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy and by differential scanning calorimetric (DSC) and elemental analysis. The toxicity study proved the novel modified cellulose to be non toxic. Rapidly disintegrating tablets of metoclopramide hydrochloride were prepared using novel modified cellulose and compared for the release of drug with control formulation, prepared using non modified microcrystalline cellulose. The tests like wetting time, water absorption ratio and in vitro disintegration time were carried out to elucidate the relationship between them. The study revealed that novel modified cellulose in a concentration of 2% released the drug faster than at a concentration higher than that. Hence it could be concluded that microcrystalline cellulose, a polymer which is devoid of superdisintegrant activity, can suitably be modified by controlled chemical modification of it with hydrochloride salt of 2-aminoethanoyl chloride or similar groups with optimum hydrophilicity and hydrophobicity to convert it into a superdisintegrant material. It can also be concluded that rapidly disintegrating tablets of metoclopramide hydrochloride can suitably be developed for the efficient management of emesis(AU)

The purpose of the study was to modify cellulose using hydrochloride salt of 2-aminoethanoyl chloride with optimum hydrophilic and hydrophobic properties to impart it a superdisintegrant activity and also to formulate and evaluate rapidly disintegrating tablets of metoclopramide hydrochloride using this novel chemically modified cellulose. A novel polymer, chemically modified cellulose was synthesized by chemically modifying microcrystalline cellulose with hydrochloride salt of 2-aminoethanoyl chloride. The formation of novel polymer was confirmed by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy and by differential scanning calorimetric (DSC) and elemental analysis. The toxicity study proved the novel modified cellulose to be non toxic. Rapidly disintegrating tablets of metoclopramide hydrochloride were prepared using novel modified cellulose and compared for the release of drug with control formulation, prepared using non modified microcrystalline cellulose. The tests like wetting time, water absorption ratio and in vitro disintegration time were carried out to elucidate the relationship between them. The study revealed that novel modified cellulose in a concentration of 2% released the drug faster than at a concentration higher than that. Hence it could be concluded that microcrystalline cellulose, a polymer which is devoid of superdisintegrant activity, can suitably be modified by controlled chemical modification of it with hydrochloride salt of 2-aminoethanoyl chloride or similar groups with optimum hydrophilicity and hydrophobicity to convert it into a superdisintegrant material. It can also be concluded that rapidly disintegrating tablets of metoclopramide hydrochloride can suitably be developed for the efficient management of emesis(AU)

Formulación y evaluación de comprimidos matriciales de clorhidrato de ambroxol, usando un polímero natural hidrofílico / Formulation and Evaluation of Matrix tablets of Ambroxol hydrochloride using Natural hydrophilic polymer

Se prepararon comprimidos matriciales de liberación prolongada de clorhidrato de ambroxol con diversas proporciones de fármaco: polímero tales como F-1(1:1), F-2(1:1,5) y F-3 (1:2). Se utilizó goma xántica para la formación de la matriz y celulosa microcristalina como diluyente. Se prepararon y evaluaron gránulos para determinar la densidad aparente sin compactar, la densidad compactada, el índice de compresibilidad, el índice de Hausner y el ángulo de reposo. Todos los gránulos se lubricaron y comprimieron con punzones planos de 9 mm. Los comprimidos se evaluaron para determinar la uniformidad de peso, el contenido de principios activos, la friabilidad, la dureza y la disolución in vitro. Todas las formulaciones se ajustaron a los estándares farmacopeicos. F-3 mostró una liberación prolongada de fármaco durante 12 horas con una liberación del 97,3% y el perfi l de liberación fue similar al de la muestra de clorhidrato de ambroxol comercial (A-MS). Además, se realizaron estudios de estabilidad según la guía ICH. La liberación de fármaco sigue cinéticas de orden cero (0,9661) y se determinó que el mecanismo era difusión combinada con erosión (AU)

Sustained release matrix tablets of ambroxol hydrochloride of different drug: polymer ratios, such as F-1(1:1), F- 2(1:1.5) and F-3 (1:2). Xanthan gum was used as matrix former and microcrystalline cellulose was used as diluent. Granules were prepared and evaluated for loose bulk density, tapped density, compressibility index, hausners ratio and angle of repose. All the granules were lubricated and compressed using 9mm fl at-faced punches. Compressed tablets were evaluated for uniformity of weight, content of active ingredient, friability, hardness and In-vitro dissolution. All the formulations showed compliance with Pharmacopoeial standards. F-3 showed the sustained release of drug for 12 hours with 97.3% release and the release profi le was close to the marketed sample of ambroxol hydrochloride (A-MS) and Stability studies were performed as per ICH guide. The drug release follows zero order kinetics (0.9661) and the mechanism was found to be diffusion coupled with erosion (AU)

Estudio de estabilidad de suspensiones farmacéuticas de liberación modificada de Clorhidrato de Morfina / Stability study of pharmaceutical suspensions for modifi ed Morphine Chlorohydrate release

El dolor crónico constituye un tema central en las ciencias de la salud contemporáneas con unos costes económicos y en términos de sufrimiento humano altamente elevados. Los opiáceos son una indicación clara para su tratamiento, donde la morfi na es el fármaco prototipo y el más representativo. Por otra parte, la vía oral es la vía de elección por ser la más cómoda y la de mayor aceptación para el paciente. Actualmente, los sistemas de liberación controlada se presentan como los más apropiados en el tratamiento del dolor crónico, estando su diseño y elaboración asociados al empleo de polímeros como vehículos transportadores del fármaco. Por tanto, la fi nalidad del presente estudio fue la preparación de una suspensión coloidal para uso oral, siendo el vehículo transportador del principio activo un pseudolátex de etilcelulosa, de manera que la morfi na quedara microencapsulada por las partículas poliméricas, obteniéndose así una forma líquida de liberación controlada, apta para personas con difi cultad en la digestión o deglución como niños o ancianos. Además se llegó al diseñó de una fórmula fi nal estable gracias al estudio de diversos viscosizantes de distinta naturaleza y a diferentes concentraciones (goma xantán, carbopol y carboximetilcelulosa sódica y avicel). Se realizaron ensayos de sedimentación y un exhaustivo estudio del comportamiento reológico para asegurar la obtención de una suspensión que no sedimentara fácilmente y se reconstruyera con facilidad mediante ligera agitación, además de presentar un adecuado fl ujo natural desde el envase

Chronic pain is a topic of major importance in modern medicine and is very costly both economically, as well as in terms of human suffering. The opiates are clearly indicated for its treatment, with morphine being the most commonly used prototype drug. Due to its convenience and high degree of acceptation, this drug is most frequently administered orally. In the treatment of chronic pain, controlled release systems are currently considered as the most appropriate. The design of such systems involves the use of polymers as transport vehicles of the drug. Consequently, the aim of this study was to prepare a colloidal suspension for oral use, using ethylcellulose pseudolatex as transport vehicle, in order to produce a liquid microencapsulated morphine preparation for controlled release, suitable for persons presenting diffi culty in swallowing and digestion, as in the case of children or the elderly. The design of an optimally stable formulation was achieved, subsequent to several viscosity studies of varying nature carried out on different concentrations of Xantham gum, carbopol and sodium carboxymethylcellulose and avicel. Additionally, exhaustive studies on rheological behaviour and sedimentation were carried out, in order to obtain a suspension that did not readily form sediments, could be easily reconstructed through slight agitation, and presented suffi cient natural fl uidity from its package presentation

FISH and Calcofluor staining techniques to detect in situ filamentous fungal biofilms in water

Filamentous fungi are a ubiquitous and diverse group of eukaryotic organisms and may contribute, along with bacteria, yeasts, protozoa and viruses, to the formation of biofilms in water distribution systems. However, fungal involvement in biofilms has not been demonstrated unambiguously. Furthermore, these fungi may be responsible for the production of tastes, odours and mycotoxins in drinking water making their early detection important. The detection of fme these problems a combination of two fluorescent techniques for direct detection was tested: (a) Fluorescence In Situ Hybridization (FISH) employing the universal rRNA probe EUK516, labelled with the red Cy3, followed by (b) staining with Calcofluor White MR2 fluorescent dye which stains fungal cell walls blue. Pure cultures of Penicillium brevicompactum were used to establish the methods followed by separate experiments with real water biofilm samples in PVC-C and cast iron coupons. FISH demonstrated eukaryotic microrganisms after approximately 5 h while the calcofluor method revealed chitinous filamentous structures in less than one hour. When the two methods were combined, additional resolution was obtained from the images of filamentous walls (blue) with intact protoplasm (red). In conclusion, FISH and Calcofluor staining provide rapid, direct and unambiguous information on the involvement of ff in biofilms which form in water(AU)

Farmacobezoar en un paciente intervenido de estenosis pilórica / Pharmacobezoar in a patient operated on for pyloric stenosis

Los bezoares son concreciones de material diverso, parcialmente digerido que se localiza en diferentes porciones del tracto digestivo llegando incluso a provocar la obstrucción del mismo. Entre los tipos de bezoar que pueden originarse y que se han descrito en la literatura científica se encuentra el bezoar debido a fármacos. Normalmente, su aparición se encuentra asociada a algún factor de riesgo predisponente. Se describe el caso de un paciente que ingresó en el hospital a través del Servicio de Urgencias por un cuadro compatible con una hemorragia digestiva. En la endoscopia que se realizó, tras su ingreso, se observó la presencia de un bezoar en cuya composición entraban a formar parte numerosos comprimidos de Adalat Oros®. Se realiza una revisión de fármacos que han originado bezoar, describiendo los factores de riesgo asociados, mecanismo de formación, aspecto que presentan y tratamientos aplicados (AU)

Biodegradation and biological treatments of cellulose, hemicellulose and lignin: an overview / Biodegradación y tratamientos biológicos de la celulosa, hemicelulosa y la lignina: un repaso

In nature, cellulose, lignocellulose and lignin are major sources of plant biomass; therefore, their recycling is indispensable for the carbon cycle. Each polymer is degraded by a variety of microorganisms which produce a battery of enzymes that work synergically. In the near future, processes that use lignocellulolytic enzymes or are based on microorganisms could lead to new, environmentally friendly technologies. This study reviews recent advances in the various biological treatments that can turn these three lignicellulose biopolymers into alternative fuels. In addition, biotechnological innovations based on natural delignification and applied to pulp and paper manufacture are also outlined (AU)

En la naturaleza, la celulosa, la lignocelulosa y la lignina son las principales fuentes de biomasa vegetal; así pues, su reciclaje es necesario para el ciclo del carbono. Cada uno de los polímeros es degradado por una variedad de microorganismos que producen una batería de enzimas que funcionan sinérgicamente. En un futuro próximo, los procesos que utilizan enzimas lignocelulolíticos o que se basan en microorganismos podrían conducir a nuevas tecnologías respetuosas con el medio ambiente. Este estudio revisa avances recientes en varios tratamientos biológicos de estos tres polímeros, que pueden convertir materiales lignicelulósicos en combustibles alternativos. Además, se destacan innovaciones biotecnológicas basadas en la deslignificación natural y aplicada a la manufactura de pulpa y papel (AU)

Efecto beneficioso de las membranas de AN69 sobre la anemia de los pacientes en hemodiálisis / Effects of biocompatible membranes on uremic anemia in hemodialysis patients

La utilización de membranas de AN69 generalmente, aumenta el aclaramiento de toxinas urémicas de mayor peso molecular e induce una menor activación de mediadores inflamatorios que las membranas celulósicas, ambos procesos podrían tener un efecto beneficioso sobre la eritropoyesis.Objetivo: Valorar la influencia de las membranas de AN69 sobre la anemia en pacientes con Insuficiencia Renal Crónica en programa de hemodiálisis (HD).Material y métodos: Estudiamos 25 pacientes en HD, dializados con membrana de cuprofán durante un mínimo de 6 meses, en situación estable, en los que se descartó otras causas de anemia (ferritina > 200 ng/ml. IST > 20 por ciento). Se dividieron en 2 grupos homogéneos. Los pacientes del grupo I (GI, n = 14) pasaron a dializarse con membrana de AN69 y los del grupo II (GII, n = 11) permanecieron con membrana cuprofán. El seguimiento fue de 5 meses. Se analizaron hematocrito ( por ciento), ferritina (ng/ml), IST ( por ciento), KTV, PCR (g/kg/día) y dosis de EPO (UI/semana) mensual en GI y Basal 2, 4 y 5 meses en GII. El hematocrito diana fue de 33 por ciento-35 por ciento.Resultados: El hematocrito en el GI aumentó de forma significativa a partir del 2º mes de tratamiento, sin modificaciones en la dosis de EPO ni en la dosis de diálisis. La ferritina e IST disminuyeron de forma significativa como reflejo de una mayor utilización. En GII no se modificó el hematocrito durante los 5 meses que duró el estudio.Conclusión: La utilización de membranas de AN69 aumenta el hematocrito de forma significativa sin modificaciones en la dosis de Eritropoyetina. (AU)