Hydrogeological constraints for the genesis of the extreme lithium enrichment in the Salar de Atacama (NE Chile): A thermohaline flow modelling approach.

The Salar de Atacama (SdA) is the largest Li reserve globally. The origin of Li, together with the rest of solutes, has been object of debate. Thus, rock weathering at low temperature, hydrothermal leaching or magmatic origin together with subsequent evaporation has been hypothesized. However, the extreme Li enrichment (>4000 mg/L) and the location of the Li-Mg-rich brines around the Salar Fault System (SFS) that crosses the nucleus of the SdA in half remain unexplained. The objective of this work is to define the thermohaline groundwater flow in the SdA basin to account for the genesis of its extreme Li enrichment. Thermohaline flow modelling has demonstrated the critical effect of the minimum hydraulic head (MHH) of the regional water table on the groundwater flow of salt flats. The MHH divides the basin into two isolated hydrodynamic systems and constitutes the endpoint towards which the most evaporated brines converge. The spatial mismatch between the locations of the Li-Mg-rich brines in the central-western zone of the nucleus (in the SFS) and the MHH in the easternmost zone of the nucleus discards recent evaporative concentration of the recharge water as the main mechanism of Li enrichment. Moreover, the persistence of a saline interface surrounding the nucleus at depth, regardless of the temperature gradient, also precludes lateral recharge (predominantly from the east) to ascend along the SFS. On the other hand, the computed thermohaline flow is compatible with the remobilization of buried layers of Li-Mg-enriched salts and/or clays by dilute recharge waters coming from the west or southwest of the basin. Here, the role of faults and density-driven flow is key to allow efficient downward and upward flow rates that favour the remobilization of Li and Mg.

Towards more sustainable brine extraction in salt flats: Learning from the Salar de Atacama.

Salt flats are hydrogeological systems with highly valuable wetland and lake ecosystems. The brine pumping carried out to extract lithium is modifying the natural evaporation discharge of salt flats. A methodology to evaluate the impacts caused on water table and evaporation discharge by brine exploitation in salt flats is proposed and applied to the Salar de Atacama. The methodology included field measurements of water table and evaporation rate, followed by its spatio-temporal analysis and the application of the results to a numerical model to improve the brine exploitation design. The spatio-temporal analysis of the water table depth and evaporation rates measured in the field concluded that the evaporation discharge decreased from 12.85 to 10.95 m3·s-1 between 1986 and 2018, that is around 15%. This reduction compensated part of the extractions and could contribute to the preservation of the mixing zone ecosystems. At present, this damping capacity is already amortized in the nucleus and the marginal zone is beginning to be affected by the brine pumping. The sensitivity of the phreatic evaporation on the water table depth justified the great uncertainty of the previous evaporation discharge estimations. Thus, an average error lower than 0.5 m was enough to modify the evaporation by >60%. Therefore, considerable effort should invested to faithfully quantify the discharge by evaporation which is critical in water balance of salt flat basins. The numerical model pointed out that the total pumping outflow should be distributed in the largest possible area. This minimizes the water table drawdown and maximizes the capacity of the evaporation decline to compensate the extractions. The results of this work serve as guidelines to improve the efficiency of future salt flat exploitations.

The effect of brine pumping on the natural hydrodynamics of the Salar de Atacama: The damping capacity of salt flats.

The Salar de Atacama is used as a case study to analyse and quantify coupled natural (evaporation and recharge) and anthropogenic processes (pumping of lithium-rich brine) to abstract their patterns to other salt flats using a three-dimensional groundwater flow model. Important changes in the dynamics of the water table between the pre-operational period (1986-1994) and operational period (1994-2015) are observed. The water table exhibited a gradual drawdown during the pre-operational period because the evaporation was greater than the recharge for most of these periods. This negative balance was counteracted by some sharp rises that were produced by direct rainfall events on the salt flat. The deep lateral recharge that arrived from the mountains did not produce abrupt changes in the water table because the rainfall events in the mountains were damped by the distance of the recharge zone and great thickness of the unsaturated zone. The natural evolution of the water table was modified by the intensive brine pumping that was performed in the south-western Salar de Atacama during the operational period. As evaporation depends on the water table depth, the pumping caused a drawdown of the water table, resulting in an evaporation rate reduction that partially compensated for the pumped brine in the water balance of the basin. This effect is defined as the damping capacity of salt flats. Thus, salt flats have a high capacity for dampening oscillations in their water table in response to both natural and anthropogenic disturbances which is of great importance for the management of lake and wetland ecosystems and brine exploitation. The limit of the dampening capacity of salt flats is defined by the evaporation extinction depth, which is in the range of 0.5-2 m.

Hydrodynamics of salt flat basins: The Salar de Atacama example.

The Salar de Atacama is one of the most well-known saline endorheic basins in the world. It accumulates the world main lithium reserves and contains very sensitive ecosystems. The objective of this work is to characterize the hydrodynamics of the Salar de Atacama, and to quantify its complex water balance prior to the intense brine extraction. The methodology and results can be extrapolated to the groundwater flow and recharge of other salt flats. A three-dimensional groundwater flow model using low computational effort was calibrated against hundreds of hydraulic head measurements. The water infiltrated from the mountains ascends as a vertical flux through the saline interface (mixing zone) produced by the density contrast between the recharged freshwater and the evaporated brine of the salt flat nucleus. This water discharges and is largely evaporated from lakes or directly from the shallow water table. On the other hand, the very low hydraulic gradients, coupled with the presence of the mixing zone that operates as barrier, leads the salt flat nucleus to act as a hydrodynamically quasi-isolated area. The computed water table shows the lowest hydraulic head in the salt flat nucleus near the discharge at the mixing zone. The groundwater balance of the Salar de Atacama in its natural regime was quantified resulting in an inflow/outflow of 14.9 m3·s-1. This balance considers the basin as an endorheic system. The very low infiltration values that are generally assumed for hyperarid basins are not consistent with the hydrogeology of the Salar de Atacama. Indeed, very high infiltration rates (up to 85% of rainfall) occur because of the high degree of fracturing of rocks and the scarce vegetation. This high infiltration is consistent with the light isotopic composition of the water from the recharge area (Altiplano). Therefore, the existence of additional inflows outside the basin is unlikely.

Analysis of tissue bioimpedance as a measurement of liver steatosis: experimental model in large animals.

BACKGROUND: Electrical bioimpedance (BI) has been used to indirectly measure steatosis. This method has not yet been established in the clinics thus experimental studies are needed in big animals. We assessed BI to measure liver steatosis in porcine animals. METHODS: Twelve large-white × Landrace pigs weighing 35 kg were allocated to a study (n = 9) and a control group (n = 3). A special diet was used to promote steatosis among the study group: methionine deficient and choline-restricted diet that contains supplements of cholesterol, collate and excess of saturated fat. Control group animals were fed a normal diet. A new tetrapolar electrode model was used for BI measurement, which were performed during open laparotomy by inserting a probe into one of the lobes. Measurements were done in the third and fourth segments of the pig liver, placing the probe either on the surface or inserted into the parenchyma of the liver. Open biopsies were obtained at the end of the measurements. Histological samples were processed and stained with hematoxylin-eosin to estimate macrosteatosis. Pearson correlation coefficient between BI and percentage steatosis were calculated at different frequencies. RESULTS: After 4 months of the special diet all the animals in the study group developed steatosis (90% to 20%), whereas none of the control group was affected. Pearson correlation coefficients between BI and percentage of steatosis were significant (0.877-0.878) with the best correlations obtained with a probe placed on the fourth segment of the liver surface and the best frequency to perform the measurements being 50 and 75 kHz. CONCLUSIONS: BI is an accurate, fast method for steatosis measurements, that is easier and cheaper than either open or needle biopsy.

Liver transplanted patients with donors older than 60 years require more hospital resources.

BACKGROUND: The increasing utilization of organs from older donors to fulfill the increasing demand for transplantation has been associated with an increased complication rate and shorter graft survival. Nevertheless, few studies have evaluated the impact of these donors on resource utilization. We sought to evaluate hospital resource utilization during the first year after liver transplantation among patients receiving a liver from a donor >60 years versus a younger donor. METHODS: This prospective study evaluated 149 consecutive liver transplantations performed in our center between 2000 and 2005. We divided the patients into 2 groups according to the donor's age; group A <60 and group B, ≥ 60 years. The follow-up was for the first year. Herein we have reported data related to resource utilization, such as number and length of stay hospitalizations, length of ICU stay; surgical and diagnostic procedures including ultrasounds, cholangiography, computed tomography or magnetic resonance imaging, as well as external consultations. RESULT: Group B patient required a greater number of hospitalizations (2.7 ± 2.4 vs 1.7 ± 1.5; P = .006), and a longer length of initial stay (37.5 ± 20.9 vs 27.8 ± 17.5 days; P = .012). There were no differences between groups concerning diagnostic and surgical procedures or external consultations. CONCLUSION: Patients transplanted from donors >60 years required more hospital resources in the first year after transplantation.

Hemorragia como forma de presentación de un adenoma hepático gigante / Hemorrhaging as a presentation form of giant hepatic adenoma

Se describe el caso de un adenoma hepático de gran tamaño que debutó con hemorragia, dolor abdominal y fiebre de varios días de evolución. Se enumeran algunas entidades que puedan estar asociadas al adenoma hepático. Se enfatiza en las pruebas de imagen como métodos para un diagnóstico correcto, que debe confirmarse con el estudio anatomopatológico (AU)

We describe the case of a teenager with a large hepatic adenoma who presented with bleeding, abdominal pain and fever for some days. Some entities may be associated with hepatic adenoma. Emphasis is placed on imaging test as methods for a correct diagnosis, which must be confirmed by pathological study (AU)

Tarjeta de Triage TASSICA 2: evaluación práctica de su funcionalidad operativa en incidentes con múltiples víctimas / No disponible

La tarjeta TASSICA 2 es una tarjeta de triage profesional dirigida a los servicios sanitarios para la intervención en incidentes con múltiples victimas (IMV). El desarrollo de la tarjeta TASSICA 2 se inicia en 2008, en el seno de un equipo de trabajo de uno de los servicios profesionales de emergencias de mayor envergadura, el SUMMA 112 de Madrid. Se plantea como instrumento que facilite la labor de los equipos de emergencias en el desempeño de sus funciones en la atención a IMV, favoreciendo al mismo tiempo la normalización de procedimientos asistenciales y contribuyendo al mantenimiento de los estándares de calidad. El objeto de este trabajo es verificar, en condiciones de simulación próximas a la intervención real en IMV, la utilidad de la tarjeta TASSICA 2 y el cumplimiento efectivo de los objetivos para los cuales fue diseñada(AU)

TASSICA 2 card is a professional triage card addressed to health services for intervention in incidents with multiple victims (IMV). The development of the card TASSICA 2 starts in 2008, within a team of one of the professional services of larger emergencies, Madrid SUMMA 112. Arises as a tool to facilitate the work of emergency teams in performing their duties in caring for IMV, while promoting the standardization of care and contributing to the maintenance of quality standards. The purpose of this paper is to verify in simulation conditions close to real action in IMV, utility TASSICA card 2 and the effective implementation of the objectives for which it was designed(AU)

Cardiac hemodynamic profiles and pro-B-type natriuretic Peptide in cirrhotic patients undergoing liver transplantation.

BACKGROUND: The aim of our study was to determine concentrations of amino-terminal pro-B-type natriuretic peptide (NT-proBNP) in patients with cirrhosis, thereby describing the hemodynamic and cardiac profiles to verify the existence of cirrhotic cardiomyopathy. METHODS: Clinical data, NT-proBNP levels, echocardiography, and right heart hemodynamic measurements were performed on all patients undergoing liver transplantation for cirrhosis. RESULTS: Our patients showed a hyperdynamic circulation with elevated left-sided pressures despite high cardiac outputs. This observation suggested abnormalities in left ventricular diastolic compliance. We verified these results, because our cohort showed a significant left ventricular mass index and, consequently, diastolic dysfunction. Mean NT-proBNP levels were high. The great expansion of central volume may explain these results and the later development of left ventricular hypertrophy. CONCLUSION: We concluded that elevated concentrations of NT-proBNP indicated the presence of hyperdynamic syndrome and cardiac dysfunction.

N-terminal brain natriuretic peptide as a diagnostic test in cirrhotic patients with pulmonary arterial hypertension.

BACKGROUND: The aim of this study was to assessed the correlation of N-terminal natriuretic peptide type B (NT-proBNP) with echocardiographic and hemodynamic indexes of right ventricular (RV) function and to evaluate the sensitivity and specificity of Doppler echocardiography in the diagnosis of portopulmonary hypertension. METHODS: All patients underwent liver transplantation for cirrhosis. We obtained clinical data, NT-proBNP levels, echocardiography, and right heart hemodynamic measurements before transplantation. RESULTS: Patients with pulmonary hypertension displayed significantly higher levels of NT-proBNP. They also showed higher model for End-stage Liver Disease scores and higher indices of RV overload on cardiac hemodynamics. The negative predictive value of echocardiography to identify pulmonary hypertension was 83%. A correlation was not observed between systolic pulmonary artery pressures measured by the two methods; however, NTproBNP showed a trend toward a significant correlation with mean pulmonary pressure as determined by hemodynamics (r = .3; P < .01). CONCLUSION: We concluded that NT-proBNP values showed significant correlations with pulmonary hypertension that could assist in a noninvasive diagnoseis for this group of patients.

Acute necrotizing pancreatitis and severe hepatic failure: description of three cases.

INTRODUCTION: Acute pancreatitis is not uncommon in fulminant hepatic failure (FHF) as confirmed by histology or serology. A few reports exist of symptomatic pancreatitis in the setting of acute viral hepatitis; the diagnosis is usually made intraoperatively or postmortem. We report three cases of liver transplant (OLT) recipients with severe acute liver failure and severe acute pancreatitis as an intraoperative finding. METHODS: We undertook a retrospective review among a large cohort of liver transplant recipients to define the impact of this problem. RESULTS: Between 1999 and 2007, 293. LTs were performed including 15 (5%) who had severe acute liver failure (nine with FHF and six with an emergency retransplantation [ER]). Among this group, three patients were diagnosed intraoperatively with acute necrotizing pancreatitis (ANP): two patients with associated FHF and one with an ER due to ABO incompatibility. None of the patients had symptoms of pancreatitis. In all, ANP was classified as Balthazar CT grade D-E, which determined the outcome. All the patients developed a pseudocyst and abscess, which required surgical drains. CONCLUSION: ANP was diagnosed as an intraoperative finding in patients with FHF. The mechanism of pancreatitis in patients with FHF is unknown. It may be multifactorial (virus, acute liver failure, hypotension, infection, drug-induced lesion,). This association leads to a worse outcome due to the complications.

The major acute phase serum protein in pigs is homologous to human plasma kallikrein sensitive PK-120.

A major acute phase protein (pig-MAP) has been isolated from the sera of pigs after turpentine injection. The protein is the pig counterpart of a recently cloned human serum protein denominated PK-120, which is a putative substrate for kallikrein [Nishimura et al., 1995 FEBS Lett. 357, 207-211]. The protein exists in other mammalian species and it is also an acute phase protein, at least in the rat. Pig-MAP shows homology, as PK-120, with the heavy chain 2 (HC-2) of the inter-alpha-trypsin inhibitor superfamily but does not possess trypsin inhibitory activity.

Characterization of the acute phase serum protein response in pigs.

Acute inflammation was induced in pigs using a single subcutaneous turpentine injection. The acute phase serum protein response was analyzed using crossed immunoelectrophoresis and immunodiffusion. The concentration of C reactive protein and haptoglobin increases 5-7 times 48 h after the injection, whereas the concentration of an alpha 2-globulin, named pig major acute phase protein (pig-MAP), increases at least 15-fold. A molecular mass of 115 kDa for pig-MAP was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This protein did not crossreact with antisera to human hemopexin, ceruloplasmin, H-kininogen and complement factor C3. Albumin and alpha-lipoprotein were negative acute phase proteins because their concentration significantly decreased during inflammation. Finally, the concentration of alpha 1-acid glycoprotein, fetuin, alpha 1-protease inhibitor, transferrin and alpha 2-macroglobulins, as well as total proteins, did not change significantly during inflammation.

[Perforated sigmoiditis. Experiences with 805 cases. A multicenter study]. / Sigmoiditis perforadas. Experiencia de 805 casos. Estudio multicéntrico.

This was a multicenter study corresponding to 40 services. For each patient, a card containing 90 questions was filled out. At the same time we sent a personal survey card with 11 criteria questions. Our cases corresponded to 805 patients, 457 males and 348 females. The highest frequency was between 50-80 years. The therapeutic methods most often used were: drainage plus Hartmann, 37.1%; drainage plus colostomy, 24.9%; resection and anastomosis without colostomy, 12.45%, and with colostomy, 5.11%; drainage plus exteriorization, 5.98%, and conservative, 4.6%. We studied the morbimortality correlation according to different anatomoclinical groups and techniques used. The results were nonsignificant for mortality and statistically significant for evisceration, eventration, diffuse peritonitis, upper gastrointestinal bleeding, anastomotic dehiscence and type of anastomosis, manual or instrumental.