Origin, accumulation and fate of dissolved organic matter in an extreme hypersaline shallow lake.

Hypersaline endorheic aquatic systems (H-SEAS) are lakes/shallow playas in arid and semiarid regions that undergo extreme oscillations in salinity and severe drought episodes. Although their geochemical uniqueness and microbiome have been deeply studied, very little is known about the availability and quality of dissolved organic matter (DOM) in the water column.. A H-SEAS from the Monegros Desert (Zaragoza, NE Spain) was studied during a hydrological wetting-drying-rewetting cycle. DOM analysis included: (i) a dissolved organic carbon (DOC) mass balance; (ii) spectroscopy (absorbance and fluorescence) and (iii) a molecular characterization with Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). The studied system stored a large amount of DOC and under the highest salinity conditions, salt-saturated waters (i.e., brines with salinity > 30%) accumulated a disproportionate quantity of DOC, indicating a significant in-situ net DOM production. Simultaneously, during the hydrological transition from wet to dry, the DOM pool showed strong alterations of it molecular composition. Spectroscopic methods indicated that aromatic and degraded DOM was rapidly replaced by fresher, relatively small, microbial-derived moieties with a large C/N ratio. FT-ICR-MS highlighted the accumulation of small, saturated and oxidized molecules (molecular O/C > 0.5), with a remarkable increase in the relative contribution of highly oxygenated (molecular O/C>0.9) compounds and a decrease of aliphatic and carboxyl-rich alicyclic moleculesThese results indicated that H-SEAS are extremely active in accumulating and processing DOM, with the notable release of organic solutes probably originated from decaying microplankton under large osmotic stress at extremely high salinities.

Geochemical and isotopic study of abiotic nitrite reduction coupled to biologically produced Fe(II) oxidation in marine environments.

Estuarine sediments are often characterized by abundant iron oxides, organic matter, and anthropogenic nitrogen compounds (e.g., nitrate and nitrite). Anoxic dissimilatory iron reducing bacteria (e.g., Shewanella loihica) are ubiquitous in these environments where they can catalyze the reduction of Fe(III) (oxyhydr)oxides, thereby releasing aqueous Fe(II). The biologically produced Fe(II) can later reduce nitrite to form nitrous oxide. The effect on nitrite reduction by both biologically produced and artificially amended Fe(II) was examined experimentally. Ferrihydrite was reduced by Shewanella loihica in a batch reaction with an anoxic synthetic sea water medium. Some of the Fe(II) released by S. loihica adsorbed onto ferrihydrite, which was involved in the transformation of ferrihydrite to magnetite. In a second set of experiments with identical medium, no microorganism was present, instead, Fe(II) was amended. The amount of solid-bound Fe(II) in the experiments with bioproduced Fe(II) increased the rate of abiotic NO2- reduction with respect to that with synthetic Fe(II), yielding half-lives of 0.07 and 0.47 d, respectively. The δ18O and δ15N of NO2- was measured through time for both the abiotic and innoculated experiments. The ratio of ε18O/ε15N was 0.6 for the abiotic experiments and 3.1 when NO2- was reduced by S. loihica, thus indicating two different mechanisms for the NO2- reduction. Notably, there is a wide range of the ε18O/ε15N values in the literature for abiotic and biotic NO2- reduction, as such, the use of this ratio to distinguish between reduction mechanisms in natural systems should be taken with caution. Therefore, we suggest an additional constraint to identify the mechanisms (i.e. abiotic/biotic) controlling NO2- reduction in natural settings through the correlation of δ15N-NO2- and the aqueous Fe(II) concentration.

Ischemic hepatitis secondary to cardiac tamponade, a rare cause / Hepatitis isquémica secundaria a taponamiento cardiaco, una causa poco frecuente.

Ischemic hepatitis (IH) is a rare entity, usually associated with hypoperfusion secondary to low cardiac output (congestive heart failure, acute myocardial infarction or dilated cardiomyopathy), followed in frequency by respiratory insufficiency and sepsis. A 49-year-old man presented at the emergency room with progressive dyspnea and hypotension, objectifying a significant increase in transaminases (aspartate transferase 5.550 U / L, alanine transferase 3.826 U / L) and LDH (10.375 U / L). Liver Doppler ultrasound was normal. The echocardiogram confirmed the suspected diagnosis of massive pericardial effusion. Cardiac tamponade is a rare cause for this clinical picture. In the case of our patient, rapid diagnosis and urgent pericardiocentesis led to his prompt recovery.

[Hepatocellular carcinoma in Navarre: study of characteristics and evolution in clinical practice]. / El hepatocarcinoma en la Comunidad Foral de Navarra: estudio de características y evolución en la práctica clínica habitual.

BACKGROUND: Hepatocellular carcinoma generally arises in a cirrhotic liver. The aim of screening is to improve survival. The aims of our study are to determine the characteristics and evolution of hepatocellular carcinoma and the effect of screening on survival, in clinical practice in Navarre. METHODS: Prospective and retrospective study of 111 patients diagnosed with hepatocellular carcinoma in public hospitals in Navarre between January 2009 and January 2015. Epidemiological, clinical, analytical, radiological characteristics, tumour staging, treatment and evolution were analyzed. Survival was compared between patients subjected to screening and those not. RESULTS: Mean age was 67 years. The patients (84.7%) were mainly male and 85.6% had cirrhosis. The most frequent aetiology was alcohol consumption (40.7%). 62.2% were diagnosed in early stages, 15.3% in intermediate and 22.5 % in advanced or terminal stages. 4.5% received transplants, 21.6% received surgical resection, 23.4% were treated with abla-tion techniques, 10.8 % with chemoembolization, 5.4% with radiembolization, 2.7% with embolization, 13.5 % with sorafenib and 18% symptomatically. Only 32 patients (28.8%) were subjected to screening. No statistical differences were found in survival depending on surveillance (32 month versus 34; p = 0.971). CONCLUSIONS: In Navarre, hepatocellular carcinoma generally appears against a background of cirrhosis, and alcohol is the most frequent aetiology. Hepatocellular carcinoma is diagnosed most frequently in early stages and out of screening practi-ces. Screening was not associated to better survival.

[Ductal regeneration in vanishing bile duct syndrome in Hodgkin's lymphoma]. / Recuperación ductular en el síndrome de los conductillos biliares evanescent en paciente con linfoma de Hodgkin.

We present the case of a 17-year-old male patient with Hodgkin's lymphoma (nodular sclerosis) in the mediastinum. During the postoperative period treatment with erythromycin was started and the patient developed progressive jaundice and cholestasis. Treatment modified for the lymphoma was initiated, which achieved complete remission and subsequent improvement and resolution of the cholestasis. Histological study of the liver revealed massive loss of bile ducts. After resolution of the cholestasis, consecutive biopsies revealed ductal proliferation. The present report therefore illustrates a case of ductopenia or vanishing bile duct syndrome (VBDS) with ad integrum regeneration of the bile ducts simultaneous with lymphoma remission. Because the 2 possible causes, erythromycin toxicity and Hodgkin's lymphoma, occurred simultaneously, the etiology of the VBDS cannot be definitively established.

[Giant esophageal hematoma: possible association with low-dose aspirin]. / Hematoma esofágico gigante: posible relación con dosis pequeñas de aspirina.

Esophageal hematoma is a rare entity that usually presents as acute thoracic pain. It may occur spontaneously or in association with an underlying disease or direct esophageal damage. The presence of coagulation disorders plays an important role in the development of hematoma. We describe the case of a female patient treated with low-dose aspirin who was diagnosed through emergency gastroscopy. We also review the literature and discuss possible causes, findings in diagnostic tests and treatment.

[Inflammatory bowel disease and amyloidosis]. / Enfermedad inflamatoria intestinal y amiloidosis.

Secondary (AA) amyloidosis is a rare but serious complication of longstanding inflammatory bowel disease that can affect the patient's prognosis more than the underlying disease. Although early diagnosis of this complication is becoming more frequent, its effective treatment continues to pose a challenge to the clinician. We present two cases of Crohn's disease complicated by secondary amyloidosis after two years, and describe their outcome.

[Brunner gland hamartoma and anisakiasis: etiologic association?]. / Hamartoma de glándulas de Brunner y anisakiasis: una asociación etiológica?

Brunner's gland hamartoma is a rare duodenal tumor generally localized in the duodenal bulb. Normally assymptomatic, it might cause upper gastrointestinal bleeding or intestinal obstruction. The diagnosis is based on upper gastrointestinal endoscopic or barium examination findings, and its treatment includes surgical or endoscopic resection, with an optimum prognosis. We present the case of a 59-year-old woman who was admitted to the hospital with an upper gastrointestinal bleeding picture. Endoscopic examination showed an ulcerated polyp in duodenal bulb which was cut with polipectomy wire. Histological slides showed a parasitic granuloma within a Brunner's gland hamartoma. Skin prick test and specific IgE determination were positive for Anisakis. Up to our knowledge, this association has never been described before.

Mineralogical composition and biomass studies of the microbial mats sediments from the Ebro Delta, Spain.

The mineral composition of the microbial mats at La Banya spit was studied. The spit is formed by a narrow sand bar and a peninsula and is located south of the main body of the Ebro Delta (Tarragona, Spain). Although quartz was the predominant mineral component in all sampling sites, clay, feldspars, calcite, aragonite, halite, dolomite and gypsum were also found. An increase in both the fine material (clay) and the halite content was observed in the sites influenced by nearby salterns. The amount of each mineral did not differ significantly along a 55 cm deep profile, except for halite and aragonite, which reached a maximum in the surface and decreased with depth. Dolomite, which ranged from 0.5 to 5% (w/w), is a possible indicator of sulfate-reducing bacteria activity in the past. Organic carbon and total nitrogen were quantified for biomass assessment. Total nitrogen ranged from 0.1 to 0.56% in the uppermost layer, where the microbial mat is active, but was undetectable at deeper layers. Organic carbon ranged from 1 to 5.5% in the active microbial mat layers and decreased to 0.3% at deeper layers. During the summer, both organic carbon and total nitrogen contents (biomass) of the microbial mat samples from some sites increase, whereas other sites show constant concentrations throughout the year, and others have a fluctuant biomass content.

Isolation and identification of autochthonous microbiota from a granitic aquifer and its variation after the bottling process.

The autochthonous microbiota from a granitic aquifer in Spain were studied. Several bacterial strains were isolated and identified. The major components of the microbiota were Pseudomonas-like strains, Flavobacterium, Acinetobacter, and Alcaligenes. The variation in the number of microorganisms after the bottling process was studied. The initial bacterial population increased over the first 5 days after bottling. This increase was higher in samples from polyvinyl chloride bottles. Sonication usually increased the total cell counts. As expected, most of the autochthonous microbiota were not detected in the viable cell counts.

Physiological Status and Community Composition of Microbial Mats of the Ebro Delta, Spain, by Signature Lipid Biomarkers.

Physiological status of microbial mats of the Ebro Delta (Tarragona, Spain) based on the extraction of lipids considered "signature lipid biomarkers" (SLB) from the cell membranes and walls of microorganisms has been analyzed. Data from a day-night cycle show significant differences in viable cells countings (PLFA cells counts) ranging from 1.5 x 10(10) to 5.0 x 10(10) cells g(-1) of sediment. Minimum values were observed at 18:00 and 6:00, when physicochemical conditions change drastically. The diversity of the microbial community was assessed by GC/MS analysis of phospholipid fatty acids (PLFA). The ratio of PLFA, representative of Gram-negative bacteria, comprises 47.8% of the total PLFA of the microbial mat community. The remaining PLFA was representative of Gram-positive (10.0%), anaerobic (5.7%), and eukaryotic microorganisms (5.7%), and other common lipids. Two different approaches were used as a comparative study to assess the physiological status of the microbial mats. Two parameters (cyclopropane fatty acids/omega7c monoenoic fatty acids, and measurement of the trans/cis monoenoic PLFA ratio) showed a minimum at midnight, suggesting the highest microbial activity. Higher values were observed at 18:00 and 6:00, coinciding with lower PLFA cell counts.

Asymptomatic gastroduodenal anisakiasis as the cause of anaphylaxis.

A great number of parasites have been reported in fish, but only a few of them are capable of infecting human beings. Anisakiasis or anisakidosis is caused by sea nematodes of the genus Anisakis, with the main implicated species being Anisakis simplex. Infection with Anisakis causes a wide spectrum of clinical manifestations, ranging from symptoms related to the upper and occasionally lower digestive tract to allergic manifestations, mainly urticaria and anaphylaxis. We report a case of asymptomatic gastroduodenal anisakiasis presenting as severe anaphylaxis.

[Chronic non granulomatous ulcerative jejunitis]. / Yeyunoileítis ulcerative crónica no granulomatosa.

Chronic non granulomatous ulcerative jejunoileitis a very infrequentity characterized by malabsorption and ulcerations of the small intestine which usually involve the jejunum and ileum. A case of a woman diagnosed with malabsorption syndrome requiring laparotomy due to worsening of a picture of malabsorption and the presence of stenosis and ileal ulceration, demonstrating villous atrophy and lymphoplasmocytic infiltration in the histology compatible with this disease is presented.

Oxygenic photosynthesis and respiratory activity in microbial mats of the ebro delta, spain, by oxygen exchange method

Photosynthetic and respiratory activities at low light intensities (300 &mgr;E m-2 s-1) in the microbial mats of the Ebro Delta were measured by the oxygen exchange method in the laboratory. The response to H2S concentration, a significant factor in the dynamics of that ecosystem, was assessed. Total photosynthesis reached 23. 78-28.17 &mgr;g O2 cm-2 h-1. Photosynthetic activity was not significantly different at the two temperatures tested. Respiratory activity reached a consumption of 6.95-8.56 &mgr;g O2 cm-2 h-1 at 25 degreesC and 11.42-11.70 &mgr;g O2 cm-2 h-1 at 35 degreesC. The Q10 value for respiration was 1.37-1.64. Oxygen production in Microcoleus chthonoplastes, the most abundant cyanobacterium in those microbial mats, was highly resistant to sulfide inhibition. Concentrations less than 0.02 mM sulfide did not affect the rate of photosynthesis. Concentrations up to 0.1 mM sulfide caused different degrees of partially reversible inhibition, with a maximum of 67% at 0.78 mM sulfide. Primary production (g C assimilated/m2/year) in those microbial mats was also assessed and compared with data from other ecosystems.

Biodegradation of Poly-(beta)-Hydroxyalkanoates in a Lake Sediment Sample Increases Bacterial Sulfate Reduction.

The addition of a poly-(beta)-hydroxyalkanoate (PHA) to incubation bottles containing anaerobic sediment from Lake Ciso (Banyoles, Catalonia, northeast Spain) was correlated with an increase in sulfide production. The concentration of PHA diminished to 51 to 99% of the initial amount. Sodium molybdate (1 mM) decreased the rate of PHA degradation and inhibited sulfide production, thus indicating that PHAs serve as carbon and electron sources for sulfate reduction.

Sensitivity of selected bacterial species to UV radiation.

The effect of exposure of bacterial suspensions to UV radiation by means of the dose-response curves was assessed. The D37 and D10 values were used for subsequent statistical analysis of the results. The aim of this article is to evaluate the sensitivity to UV radiation of several microorganisms of different habitats (Rhizobium meliloti, Rhodobacter sphaeroides, Escherichia coli, and Deinococcus radiodurans), two mutants with nonfunctional SOS DNA repair system (R. meliloti recA- and E. coli recA-), and a mutant in the synthesis of carotenoids (R. sphaeroides crtD). The results reveal that D. radiodurans was an extremely resistant bacterium, R. meliloti was more resistant than R. sphaeroides, and E. coli was the most sensitive bacterium tested. The high sensitivity of recA- mutants was also verify. Moreover, it seems that the possession of pigments had no important effect in the sensitivity of R. sphaeroides to UV radiation.

Microbial degradation of poly-beta-hydroxyalkanoates.

The search for new materials that are not hazardous to the environment has become a major issue in our society, engaged as it is in the attainment of sustainable development. Poly-beta-hydroxyalkanoates (PHA), produced exclusively by prokaryotes, can be used as thermoplastics and are fully biodegradable and innocuous to the environment. Biodegradability testing has quantified the capacity of microorganisms to degrade such new chemical compounds, particularly polyhydroxyalkanoates. Standardized tests may also discover new microorganisms and environmental conditions that accelerate biodegradation. We evaluate various techniques used to assess the biodegradability of PHA, and which may also be applied to test other kinds of polymers.

Distribution of types of microbial mats at the Ebro Delta, Spain.

The distribution and types of microbial mats of the Ebro Delta (Catalonia, Spain) are described. The studied area is La Banya spit, formed by a narrow sand bar and a peninsula, located south of the main body of the Ebro Delta. Sea water can penetrate into the back shore through channel inlets, cutting the steeper coastal barrier of the open sea side of the spit or through the complex drainage channel system of the low-energy beaches in the inner Alfacs Bay. Sea water can stay in the back shore almost permanently, trapped in isolated depressions and lagoons. The surface distribution of microbial mats in La Banya spit has been studied by means of a detailed interpretation of vertical aerial photographs and field work consisting of mapping and sampling. The observed different ratios of cyanobacteria, as well as the presence and thickness of the layers of anoxygenic sulfur phototrophic bacteria, depend on the moisture content, the system stability, and the age of the microbial mat. Lyngbya, Oscillatoria, and Spirulina are the first cyanobacteria able to colonize the bare sediment. Lyngbya dominates in young microbial mats and in mats exposed to frequent desiccation. Microcoleus is the second most important colonist in the microbial succession. In relation to water, the alternation of emergence and submergence is optimal for the maximal development of Microcoleus-dominated microbial mats. We classify the microbial mats of the Ebro Delta into five main types: (i) Lyngbya-dominated type, in which the anoxygenic phototrophic bacteria are absent and the black layer of sulfate-reducers is very thin; (ii) Spirulina-dominated type; (iii) Oscillatoria-dominated type, which is found only at one site and covers a small area--this type, like the Spirulina-type mat, is not common in the Ebro Delta; (iv) Lyngbya/Microcoleus-transition type, in which Microcoleus and Lyngbya coexist in similar proportions--in the more developed mats of this group a layer of purple bacteria is usually present, and the black layer of sulfate-reducers is usually also well developed; and (v) Microcoleus-dominated type--in La Banya spit, this type is found in localities with relatively stable conditions. These areas are wet during most of the year. After appropriate conditions of diagenesis, the most highly developed microbial mats may be preserved as laminated hard sediments. The field study has been completed with cultivation, isolation, and identification of the main cyanobacterial genera under laboratory conditions.