The abundance of comammox bacteria was higher than that of ammonia-oxidizing archaea and bacteria in rhizosphere of emergent macrophytes in a typical shallow lake riparian / La abundancia de bacterias comammox fue mayor que la de arqueas y bacterias oxidantes de amoníaco en la rizosfera de macrófitos emergentes en un típico lago ribereño poco profundo

Complete ammonia oxidation (comammox) bacteria can complete the whole nitrification process independently, which not only challenges the classical two-step nitrification theory but also updates long-held perspective of microbial ecological relationship in nitrification process. Although comammox bacteria have been found in many ecosystems in recent years, there is still a lack of research on the comammox process in rhizosphere of emergent macrophytes in lakeshore zone. Sediment samples were collected in this study from rhizosphere, far-rhizosphere, and non-rhizosphere of emergent macrophytes along the shore of Lake Liangzi, a shallow lake. The diversity of comammox bacteria and amoA gene abundance of comammox bacteria, ammonia-oxidizing archaea (AOA), and ammonia-oxidizing bacteria (AOB) in these samples were measured. The results showed that comammox bacteria widely existed in the rhizosphere of emergent macrophytes and fell into clade A.1, clade A.2, and clade B, and clade A was the predominant community in all sampling sites. The abundance of comammox amoA gene (6.52 × 106–2.45 × 108 copies g−1 dry sediment) was higher than that of AOB amoA gene (6.58 × 104–3.58 × 106 copies g−1 dry sediment), and four orders of magnitude higher than that of AOA amoA gene (7.24 × 102–6.89 × 103 copies g−1 dry sediment), suggesting that the rhizosphere of emergent macrophytes is more favorable for the growth of comammox bacteria than that of AOB and AOA. Our study indicated that the comammox bacteria may play important roles in ammonia-oxidizing processes in all different rhizosphere regions.(AU)

Carglumic acid (Carbaglu(R)) treatment in hyperammonemia post liver transplantation / Tratamiento con ácido carglúmico (Carbaglu(R)) en la hiperamoniemia post transplante hepático

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Cyanobacterial extract-mediated synthesis of silver nanoparticles and their application in ammonia sensing

Green route for silver nanoparticle synthesis has gained increasing attention. Cyanobacteria are one of the promising organisms to produce a number of secondary metabolites that are capable of reducing silver ions to small-sized silver nanoparticles. In the present study, we employed an aqueous extract of the cyanobacterium Haloleptolyngbya alcalis KR2005/106 isolated from a soda lake for biosynthesis of silver nanoparticles (AgNPs). The extract acted as a reducing agent for AgNPs synthesis and resulted formation of nanoparticles <50 nm in size. In this study, synthesis of AgNPs obtained only in the sample exposed to photosynthetically active radiation (PAR) while the synthesis of AgNPs was not observed in the samples kept in dark. The biogenic fabrication of AgNPs was carried out by optimizing several governing parameters such as concentration of the silver nitrate solution, pH, temperature, and amount of biomass. Results obtained through different analytical techniques revealed that cyanobacterial taxon H. alcalis isolated from saline-alkaline habitat is a potential candidate for biosynthesis of optimum-sized spherical AgNPs. Surface plasmon resonance (SPR) property of AgNPs was exploited for aqueous ammonia sensing and revealed that AgNPs synthesized using aqueous extract of cyanobacterium H. alcalis could be employed for colorimetric detection of dissolved ammonia for monitoring quality of water

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Desinfectantes químicos: Fenoles y tensioactivos (Amonios cuaternarios) / No disponible

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Chlorine Inhalation Challenge in Humans: Development of a New Closed-Circuit Methodology / Prueba de provocación bronquial con cloro en humanos: desarrollo de una nueva metodología con circuito-cerrado

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Metformin modifies glutamine metabolism in an in vitro and in vivo model of hepatic encephalopathy

Aim: to analyze the effect of metformin on ammonia production derived from glutamine metabolism in vitro and in vivo. Methods: twenty male Wistar rats were studied for 28 days after a porto-caval anastomosis (n = 16) or a sham operation (n = 4). Porto-caval shunted animals were randomized into two groups (n = 8) and either received 30 mg/kg/day of metformin for two weeks or were control animals. Plasma ammonia concentration, Gls gene expression and K-type glutaminase activity were measured in the small intestine, muscle and kidney. Furthermore, Caco2 were grown in different culture media containing glucose/glutamine as the main carbon source and exposed to different concentrations of the drug. The expression of genes implicated in glutamine metabolism were analyzed. Results: metformin was associated with a significant inhibition of glutaminase activity levels in the small intestine of porto-caval shunted rats (0.277 ± 0.07 IU/mg vs 0.142 ± 0.04 IU/mg) and a significant decrease in plasma ammonia (204.3 ± 24.4 µg/dl vs 129.6 ± 16.1 µg/dl). Glucose withdrawal induced the expression of the glutamine transporter SLC1A5 (2.54 ± 0.33 fold change; p < 0.05). Metformin use reduced MYC levels in Caco2 and consequently, SLC1A5 and GLS expression, with a greater effect in cells dependent on glutaminolytic metabolism. Conclusion: metformin regulates ammonia homeostasis by modulating glutamine metabolism in the enterocyte, exerting an indirect control of both the uptake and degradation of glutamine. This entails a reduction in the production of metabolites and energy through this pathway and indirectly causes a decrease in ammonia production that could be related to a decreased risk of HE development

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Déficit parcial de ornitin-carbamil-transferasa. A propósito de un caso / Partial deficiency of ornithine transcarbamylase. A case report

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Phylogenetic characterization and quantification of ammonia-oxidizing archaea and bacteria from Lake Kivu in a long-term microcosm incubation

A microcosm cultivation-based method was set up to investigate the growth of ammonia-oxidizing archaea (AOA), isolated from a water sample acquired at a depth of 50 m from the northern basin of Lake Kivu. For this purpose, both CARD-FISH and qPCR targeting of archaeal 16S rRNA and amoA genes were used. Archaeal cell growth at the end of the 246-day microcosm experiment accounted for 35% of the SybrGold-stained cells, which corresponded to 6.61 x 10(6) cells/ml and 1.76 +/- 0.09 x 10(6) archaeal 16S rRNA gene copies/ml. Clone libraries and DGGE fingerprinting confirmed the dominance of AOA phylotypes in the archaeal community microcosm. The majority of the identified archaeal 16S rRNA gene sequences in the clone libraries were affiliated with Thaumarchaeota Marine Group 1 .1a. Subsequent cultivation of the AOA community on deep-well microtiter plates in medium containing different carbon sources to stimulate archaeal growth failed to show significant differences in archaeal abundance (ANOVA t14 = -1.058, P = 0.308 and ANOVA t14= 1.584, P = 0.135 for yeast extract and simple organic acids, respectively). The lack of growth stimulation by organic compounds is in concordance with the oligotrophic status of Lake Kivu. Finally, the addition of antibiotics to the growth medium resulted in archaeal cell counts that were significantly lower than those obtained from cultures in antibiotic-free medium (ANOVA t14 = 12.12, P < 0.001) (AU)

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La acidosis tubular renal distal: una enfermedad hereditaria en la que no se pueden eliminar los hidrogeniones / Distal renal tubular acidosis: a hereditary disease with an inadequate urinary H+ excretion

La acidosis tubular renal distal (ATRD) o ATR tipo I se caracteriza por una disminución en la excreción urinaria de los hidrogeniones H+ y del amonio. En los niños afectados por ATRD hay retraso en el crecimiento, vómito, estreñimiento, falta de apetito, polidipsia y poliuria, nefrocalcinosis, debilidad y hasta parálisis muscular por la hipopotasemia. En este trabajo se resumen los avances en el estudio genético de la ATRD en las poblaciones hasta ahora estudiadas. La ATRD es heterogénea, por lo que también se analizan los transportadores y canales iónicos que se han identificado hasta ahora en las células intercaladas alfa del túbulo colector, y que podrían explicar los casos de ATRD que no se asocian con los genes hasta ahora estudiados. La ATRD puede ser autosómica dominante o autosómica recesiva. La ATRD autosómica recesiva se manifiesta en los primeros meses de vida, cursa con nefrocalcinosis y sordera temprana o tardía. La ATRD autosómica dominante es menos severa y aparece en la adolescencia o en la etapa adulta, y puede o no presentar nefrocalcinosis. En las células intercaladas alfa de los túbulos colectores se lleva a cabo la excreción urinaria de la carga ácida: los ácidos titulables (fosfatos) y el amonio. La ATRD autosómica recesiva se asocia con mutaciones en los genes ATP6V1B1, ATP6V0A4 y SLC4A1, los cuales codifican las subunidades a4 y B1 de la V-ATPasa y el intercambiador de bicarbonato/cloruro AE1, respectivamente. En contraste, la ATRD autosómica dominante se relaciona con mutaciones solo en AE1 (AU)

Distal renal tubular acidosis (dRTA) or RTA type I is characterised by reduced H+ hydrogen ions and ammonium urinary excretion. In children affected by dRTA there is stunted growth, vomiting, constipation, loss of appetite, polydipsia and polyuria, nephrocalcinosis, weakness and muscle paralysis due to hypokalaemia. This work summarises progress made in dRTA genetic studies in populations studied so far. DRTA is heterogeneous and as such, transporters and ion channels are analysed which have been identified in alpha-intercalated cells of the collecting duct, which could explain cases of dRTA not associated with the hitherto studied genes. DRTA can be autosomal dominant or autosomal recessive. Autosomal recessive dRTA appears in the first months of life and progresses with nephrocalcinosis and early or late hearing loss. Autosomal dominant dRTA is less severe and appears during adolescence or adulthood and may or may not develop nephrocalcinosis. In alpha-intercalated cells of the collecting duct, the acid load is deposited into the urine as titratable acids (phosphates) and ammonium. Autosomal recessive dRTA is associated with mutations in genes ATP6V1B1, ATP6V0A4 and SLC4A1, which encode subunits a4 and B1 of V-ATPase and the AE1 bicarbonate/chloride exchanger respectively. By contrast, autosomal dominant dRTA is only related to mutations in AE1 (AU)

Metabolic acidosis and progression of chronic kidney disease: incidence, pathogenesis, and therapeutic options

In the chronic kidney disease population metabolic acidosis is prevalent presenting already in the early stages of renal dysfunction. The pathogenesis associates the lack of bicarbonate production with the accumulation of organic/inorganic acids and the development of tubulointerstitial damage through ammonium retention and complement deposition. The empiric use of oral sodium bicarbonate represents an interesting therapeutic option that has been documented in a few clinical trials in human subjects. The availability of oral sodium, in its diverse forms, represents an inexpensive and simple way of treating an entity that could hasten the progression of kidney disease, as well as protein catabolism, bone disease and mortality (AU)

Hay una prevalencia importante de la acidosis metabólica en los pacientes que padecen enfermedad renal crónica, presentándose en niveles tempranos de pérdida de filtrado glomerular. La patogénesis se basa en la falta de síntesis de bicarbonato sérico con la acumulación de ácidos de naturaleza orgánica e inorgánica, ocasionando daño tubulointersticial a través de la retención de amoniaco y el depósito de complemento, aunque esta última hipótesis se ha cuestionado en el pasado. El uso empírico de bicarbonato oral representa una opción terapéutica interesante que ha sido utilizada en estudios clínicos recientes. La disponibilidad de bicarbonato de sodio oral en sus diversas formas representa una opción barata y simple de utilizar para decelerar la progresión de la enfermedad renal, sin mencionar las mejoras en el catabolismo proteico, la osteodistrofia renal y la mortalidad (AU)

Actualización en el tratamiento de la encefalopatía hepática / Update on the management of hepatic encephalopathy

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La encefalopatía hiperamonémica, una posible complicación por derivación urinaria tras cistectomía radical. Revisión de la literatura a proposito de un caso / Hyperammonaemic encephalopathy, possible complication after urinary diversion in radical cystectomy. Review of the literature with regard to a clinical case

Introducción: La cistectomía radical es una intervención con una elevada morbilidad. Las derivaciones postcistectomía pueden ocasionar complicaciones metabólicas como la encefalopatía hiperamonémica. Caso Clínico: Presentamos el caso de una paciente cistectomizada por un carcinoma vesical con posterior ureterosigmoidostomía. Tras la intervención acudió en 4 ocasiones con síntomas neurológicos y confusión. Todo el estudio analítico y pruebas de imagen fueron normales. Los niveles de amonio en sangre estaban elevados. Tras tratamiento de soporte y hemodiálisis la clínica desapareció. Posteriormente fue sometida a una nueva derivación quirúrgica (conducto ileal). Discusión: El empleo de técnicas de derivación continentes tras la cistectomía se aconseja ante la importante afectación de la calidad de vida que produce el conducto ileal. Sin embargo, estas técnicas tienen complicaciones, como la encefalopatía hiperamonémica de causa no hepática. La elevada absorción de amonio por el epitelio intestinal de la neovejiga induce una encefalopatía. Es esencial su diagnóstico temprano con el fin de iniciar un tratamiento eficaz

Introduction: Radical cystectomy is an intervention with an important morbidity. Urinary diversion is a possible cause of metabolic complications like hyperammonaemic encephalopathy. Case report: We present the case of a patient treated with a radical cystectomy and modified ureterosigmoidostomy after diagnosis of bladder cancer. After surgery the patient presented in 4 ocasions recurrent episodic confusion. Laboratory and image tests were normal. Levels of seric ammonium was increased. After supportive treatment and hemodyalisis symptoms disappeared. Later patient was reoperated and a reconstruction to ileal conduit was made. Discussion: Continent urinary diversions are advised due to important negative impact on quality of life produced by ileal conduit. However these diversions have several complications, like encephalopathy secondary to non-hepatic hyperammonaemia. Increased absortion of ammonium by intestinal tissue of the new-ladder induces encephalopathy. Early diagnosis of this complication is essencial in order to administer an effective treatment

Nevo comedoniano unilateral: eficacia tras el tratamiento con lactato amónico al 12 por ciento / Unilateral nevus comedonicus: efficacy after treatment with 12% ammonium lactate

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Polygenic analysis of ammonia-oxidizing bacteria using 16S rDNA, amoA, and amoB genes / Análisis poligénico de cepas de bacterias oxidadoras de amoníaco por medio de los genes 16S rDNA, amoA y amoB

Finding a unique molecular marker capable of quickly providing rigorous and useful phylogenetic information would facilitate assessing the diversity of ammonia-oxidizing bacteria in environmental samples. Since only one of several available markers can be used at a time in these kinds of studies, the 16S rDNA, amoA and amoB genes were evaluated individually and then compared in order to identify the one that best fits the information provided by the composite dataset. Distance-based neighbor-joining and maximum parsimony trees generated using the sequences of the three mentioned genes were analyzed with respect to the combined polygenic trees. Maximum parsimony trees were found to be more accurate than distance-based ones, and the polygenic topology was shown to best fit the information contained in the sequences. However, the taxonomic and phylogenetic information provided by the three markers separately was also valid. Therefore, either of the functional markers (amoA or amoB) can be used to trace ammonia oxidizers in environmental studies in which only one gene can be targeted (AU)

Encontrar un marcador molecular único capaz de proporcionar rápidamente información filogenética rigurosa y útil facilitaría evaluación de la diversidad de las bacterias oxidadoras de amoníaco en muestras ambientales. En esta clase de estudios no se puede utilizar simultáneamente más que uno de los marcadores disponibles. Los genes 16S rDNA, amoA y amoB se evaluaron individualmente para identificar el que se ajusta mejor a la información proporcionada por el conjunto de datos de los tres genes. Se compararon los árboles de Neighbor-Joining, basados en las distancias, y los árboles de máxima parsimonia basados en las secuencias conocidas de los tres genes mencionados, y se analizaron en relación con los árboles poligénicos construidos con la información combinada proporcionada por los tres genes. Los árboles de máxima parsimonia resultaron más fieles que los basados en las distancias, y la topología poligénica era la que mejor se ajustaba a la información contenida en las secuencias. Sin embargo, la información taxonómica y filogenética proporcionada por los tres marcadores por separado también resultó válida. Por tanto, cualquiera de los dos marcadores funcionales (amoA o amoB) se puede utilizar para detectar los oxidantes del amoníaco en estudios ambientales en los que solamente puede usarse un gen (AU)

MARS y el tratamiento de la encefalopatía hepática / MARS and treatment of hepatic encephalopathy

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Trombosis del senolongitudinal superior en un lactante: ¿secundaria a una exposición prolongada a mesalacina? / Thrombosis of the superior sagittal sinus in a breast-fed infant: secondary to prolonged exposure to mesalazine?

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Amoníaco y transaminasas en sangre en el recién nacido a término afectado de asfixia perinatal / Blood ammonia and transaminsases in a term infant with perinatal asphyxia

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Hipertensión intracraneal benigna. Antecedentes, clínica y tratamiento en una serie de 41 pacientes / Benign intracranial hypertension. History, clinical features and treatment in a series of 41 patients

Introducción. La hipertensión intracraneal benigna (HICB) es un síndrome caracterizado por la elevación anormal de la presión intracraneal con una composición normal del líquido cefalorraquídeo (LCR) y en ausencia de hidrocefalia o lesión expansiva intracraneal. Objetivo. El presente trabajo pretende, mediante el análisis de pacientes diagnosticados de HICB, evaluar sus características epidemiológicas, clínicas y terapéuticas. Pacientes y métodos. Se revisaron 87 protocolos de pacientes diagnosticados de hipertensión intracraneal con TAC cerebral normal, entre los años 1999 y 2002. Se seleccionaron 41 pacientes según los criterios de HICB. Resultados. Los resultados alcanzados nos permiten dibujar el siguiente perfil: una mujer (más del 70 por ciento) de entre 21 y 30 años (29 por ciento), fumadora, obesa (59 por ciento), con aumento de peso reciente (37 por ciento), que consulta tras llevar más de tres meses con cefalea (89 por ciento), alteraciones de la agudeza visual (más del 50 por ciento) y náuseas con algún vómito (más del 40 por ciento). En la exploración presenta papiledema bilateral (100 por ciento), una presión de LCR mayor de 20 cmH2O (40,78 ñ 15,55 cmH2O) con composición normal, sin alteraciones en las pruebas de neuroimagen. Conclusión. El tratamiento con acetazolamida fue favorable (51,2 por ciento), y resultó definitiva (70 por ciento) la derivación lumboperitoneal cuando fue necesaria (30,7 por ciento); son mejores estas cifras si se consideran los pacientes con una menor presión del LCR en el momento del diagnóstico (p < 0,035) (AU)

Introduction. Benign intracranial hypertension (BIH) is a syndrome characterized by the abnormal elevation of the pressure intracranial with a normal composition of the cerebrospinal fluid (CSF) and in absence of ventriculomegaly or someone intracranial expansive lesion. Aim. The present work seeks, by means of the analysis of diagnosed patients of HICB, to evaluate its epidemic, clinical and therapeutic features. Patients and methods. 87 protocols intracranial hypertension diagnosed patients with normal cerebral TAC were revised, between 1999 and 2002. 41 patients were selected assisting to the approaches of hypertension benign intracranial. Results. The reached results allow us to draw the following profile, a woman (> 70%) of between 21 and 30 years (29%), smoker, obese (59%) with an recent increase of weight (37%) that consults after taking more than three months with headache (89%), alterations of the visual acuity (> 50%) and nauseas with some vomit (> 40%). In the exploration it presents bilateral papilledema (100%), a pressure of LCR bigger than 20 cmH2O (40,78 ± 15,55 cmH2O) with normal composition, without alterations in the neuroradiological study results. Conclusion. The treatment with acetazolamide was favourable (51,2%), being definitive (70%) the lumbar peritoneal shunt when it is specified (30,7%), being improves these figures in those patients with a smaller pressure of the LCR in the moment of the diagnosis (p<0,035) (AU)