Nitroimidazoles adsorption on activated carbon cloth from aqueous solution.

The objective of this study was to analyze the equilibrium and adsorption kinetics of nitroimidazoles on activated carbon cloth (ACC), determining the main interactions responsible for the adsorption process and the diffusion mechanism of these compounds on this material. The influence of the different operational variables, such as ionic strength, pH, temperature, and type of water (ultrapure, surface, and waste), was also studied. The results obtained show that the ACC has a high capacity to adsorb nitroimidazoles in aqueous solution. Electrostatic interactions play an important role at pH<3, which favors the repulsive forces between dimetridazole or metronidazole and the ACC surface. The formation of hydrogen bonds and dispersive interactions play the predominant role at higher pH values. Modifications of the ACC with NH3, K2S2O8, and O3 demonstrated that its surface chemistry plays a predominant role in nitroimidazole adsorption on this material. The adsorption capacity of ACC is considerably high in surface waters and reduced in urban wastewater, due to the levels of alkalinity and dissolved organic matter present in the different types of water. Finally, the results of applying kinetic models revealed that the global adsorption rate of dimetridazole and metronidazole is controlled by intraparticle diffusion.

[Is lactate a good indicator of brain tissue hypoxia in the acute phase of traumatic brain injury? Results of a pilot study in 21 patients]. / ¿Es el lactato un buen indicador de hipoxia tisular? Resultados de un estudio piloto en 21 pacientes con un traumatismo craneoencefálico.

UNLABELLED: Lactate and the lactate-pyruvate index (LPI) are two hypoxia markers widely used to detect brain tissue hypoxia in patients with acute traumatic brain injury. These two markers have a more complex behavior than expected as they can be abnormally high in circumstances with no detectable brain hypoxia. This condition must be considered in the differential diagnosis because it also reflects an alteration of brain energy metabolism. OBJECTIVES: 1. To describe cerebral energy metabolism characteristics observed in the acute phase of traumatic brain injury (TBI) based on two traditional indicators of anaerobic metabolism: lactate and LPI, 2. To determine the concordance between these two biomarkers in order to classify the incidence of anaerobic metabolism and 3. To classify the different types of metabolic abnormalities found in patients with moderate and severe TBI using both lactate and LPI. MATERIALS AND METHODS: Twenty-one patients were randomly selected from a cohort of moderate or severe TBI patients admitted to the neurotraumatology intensive care unit. All of them who underwent both cerebral microdialysis and brain tissue oxygen monitoring (PtiO(2)). We analyzed the levels of lactate and the LPI for every microvial within the first 96 hours after head trauma. These data were correlated with PtiO(2) values. RESULTS: Lactate levels and the LPI were respectively increased during 49.5% and 38.4% of the monitoring time. The incidence and behavior of high levels of both markers were extremely heterogeneous. The concordance between these two biomarkers to determine episodes of dysfunctional metabolism was very weak (Kappa Index=0.29; IC 95%: 0.24-0.34). Based on the levels of lactate and the LPI, we defined four metabolic patterns: I: L>2.5 mmol/L and LPR>25; II: L>2.5 mmol/L and LPR< or = 25; III: L< or = 2.5 mmol/L and LPR< or = 25; IV: L< or = 2.5 mmol/L and LPR>25). In more than 80% of cases in which lactate or LPI were increased, PtiO(2) values were within the normal range (PtiO(2)> 15 mmHg). CONCLUSIONS: Increased lactate and LPI were frequent findings after acute TBI and in most cases they were not related to episodes of brain tissue hypoxia. Furthermore, the concordance between both biomarkers to classify metabolic dysfunction was weak. LPI and lactate should not be used indistinctly in everyday clinical practice because of the weak correlation between these two markers, the difficulty in their interpretation and the heterogeneous and complex nature of the pathophysiology. Other differential diagnoses apart from tissue hypoxia should always be considered when high lactate and/or LPI are detected in the acute injured brain.

Adsorption mechanisms of metal cations from water on an oxidized carbon surface.

Adsorption of Cr(III), Mn(II), Cu(II) and Zn(II) on an oxidized activated carbon cloth was studied. Its surface chemistry was characterized by potentiometric titration. This technique revealed the amount of surface oxygen functionalities and their acidity constant distribution. The acidity constant range involved in the metal cation adsorption was obtained from this distribution. Metal cation adsorption increased with higher adsorption temperature due to the increase in the negative surface charge of the oxidized activated carbon. Adsorption was by proton exchange and the number, amount and strength of the surface acid groups involved could be obtained. The proton exchange was by an inner-sphere or outer-sphere surface metal complex formation mechanism. In the case of divalent cation adsorption, the increase in temperature changed the adsorption mechanism from outer-sphere to inner-sphere. However, the adsorption mechanism of Cr(III) was outer-sphere and independent of temperature. Adsorption capacity augmented with the increase in the charge-to-size ratio of the hexa-aquo cations. In addition, the adsorption capacity of divalent cations increased with the rise in stability of the surface metal complex formed.

[High-resolution microdialysis. methodological issues and application to the study of inflammatory brain response]. / Microdiálisis de alta resolución. Aspectos metodológicos y aplicación al estudio de larespuesta inflamatoria cerebral.

Cerebral microdialysis is a tool that provides very relevant information in the metabolic monitoring of brain injured patients. It is a particularly effective technique for the detection and analysis of small molecules, given that the pores of the dialysis membrane act as a barrier to restrict the transport of larger species, such as proteins and other macromolecules. The recent availability of microdialysis catheters with membrane pores of larger size, termed "high resolution" catheters, would widen the spectrum of molecules detectable in the dialisate. However, there are technical complications related to the use of these catheters for such purposes, and therefore, this potential capacity for the recovery of proteins needs to be validated, in order to begin its application as a tool in studies of proteomics associated with brain injuries. The following review depicts the basic principles of microdialysis, and describes some of the issues involved in the recovery of molecules in the dialisate, including the physical properties of the dialysis membrane and of the molecules of interest.

Removal of diuron and amitrole from water under static and dynamic conditions using activated carbons in form of fibers, cloth, and grains.

This study investigated the removal of the herbicides diuron and amitrole from water under static and dynamic conditions using different activated carbons in the form of fibers, cloth, and grains. In all cases, there was much greater adsorption of diuron than of amitrole due to the lower solubility, greater hydrophobicity, and larger dipolar moment of the former. The activated carbon cloth was the best adsorbent for diuron under dynamic conditions because it had the largest mesopore volume, water-accessible pore volume, and surface area. However, the best adsorbent for amitrole under dynamic conditions was the granular activated carbon due to its higher surface basicity. Comparisons using the best adsorbent for each herbicide showed that diuron was removed by the activated carbon more efficiently compared with amitrole under both dynamic and static conditions.

Effect of surface chemistry, solution pH, and ionic strength on the removal of herbicides diuron and amitrole from water by an activated carbon fiber.

A study was conducted on the effects of carbon surface chemistry, solution pH, and ionic strength on the removal of diuron and amitrole from aqueous solutions by adsorption on an as-received and oxidized activated carbon fiber. Results obtained were explained by the surface characteristics of the adsorbents and the characteristics of the herbicide molecules. Under the experimental conditions used, diuron uptake was much higher than that of amitrole, despite its larger molecular dimensions, due to the lesser water solubility, greater hydrophobicity, and larger dipolar moment of diuron compared with amitrole. Uptake variations associated with differences in carbon surface oxidation, solution pH, and ionic strength were explained by corresponding changes in electrostatic, hydrophobic, and van der Waals interactions.

Activated carbon and tungsten oxide supported on activated carbon catalysts for toluene catalytic combustion.

We have used activated carbon (AC) prepared from almond shells as a support for tungsten oxide to develop a series of WOx/AC catalysts for the catalytic combustion of toluene. We conducted the reaction between 300 and 350 degrees C, using a flow of 500 ppm of toluene in air and space velocity (GHSV) in the range 4000-7000 h(-1). Results show that AC used as a support is an appropriate material for removing toluene from dilute streams. By decreasing the GHSV and increasing the reaction temperature AC becomes a specific catalyst for the total toluene oxidation (SCO2 = 100%), but in less favorable conditions CO appears as reaction product and toluene-derivative compounds are retained inside the pores. WOx/AC catalysts are more selective to CO2 than AC due to the strong acidity of this oxide; this behavior improves with increased metal loading and reaction temperature and contact time. The catalytic performance depends on the nonstoichiometric tungsten oxide obtained during the pretreatment. In comparison with other supports the WOx/AC catalysts present, at low reaction temperatures, higher activity and selectivity than WO, supported on SiO2, TiO2, Al2O3, or Y zeolite. This is due to the hydrophobic character of the AC surface which prevents the adsorption of water produced from toluene combustion thus avoiding the deactivation of the active centers. However, the use of WOx/AC system is always restricted by its gasification temperature (around 400 degrees C), which limits the ability to increase the conversion values by increasing reaction temperatures.

Cadmium ion adsorption on different carbon adsorbents from aqueous solutions. Effect of surface chemistry, pore texture, ionic strength, and dissolved natural organic matter.

Adsorption of Cd(II) species at pH = 5 was studied on three carbon adsorbents: granular activated carbon, activated carbon fiber, and activated carbon cloth. As-received and oxidized adsorbents were used. Cd(II) adsorption greatly increased after oxidation due to the introduction of carboxyl groups. The use of a buffer solution to control the pH introduced some changes in the surface chemistry of carbons through the adsorption of one of the compounds used, biphthalate anions. The increase in ionic strength reduced Cd(II) uptake on both as-received and oxidized carbons due to a screening of the electrostatic attractions between the Cd(II) positive species and the negative surface charge, which in the case of as-received carbons derived from the biphthalate anions adsorbed and in the oxidized ones from the carboxyl groups. Tannic acid was used as a model compound for natural organic matter. Its adsorption was greatly reduced after oxidation, and most of the carbon adsorbents preadsorbed with tannic acid showed an increase in Cd(II) uptake. In the case of competitive adsorption between Cd(II) species and tannic acid molecules, there was a decrease in Cd(II) uptake on the as-received carbon whereas the contrary occurred with the oxidized carbons. These results illustrate the great importance of carbon surface chemistry in this competitive adsorption process. Finally, under all experimental conditions used, when the adsorption capacity of carbons was compared under the same conditions it increased in the following order: granular activated carbon < activated carbon fiber < activated carbon cloth.

Extravasación pleural de sustancia quimioterápica tras canulación de vena subclavia / Pleural extravasation of chemotherapeutic substance after cannulation of the subclavian vein

La canulación de una vía venosa central no está exenta de complicaciones y una de ellas es la producción de hidrotórax por instilación de sustancias. Presentamos el caso de una paciente que presentó hidrotórax de contenido quimioterápico. El mecanismo de acción de este hidrotórax fue debido a la disección de ambas hojas pleurales ocasionada por la progresión de la punta del catéter que quedó colocado entre ambas hojas. Planteamos la necesidad de controles más exhaustivos tras la canulación de catéteres venosos centrales (AU)

Morfina asociada a bupivacaína intracisternalen el tratamiento del dolor oncológico maxilofacial / Morphine associated to intracisternal bupivacaine for the management of maxillofacial cancer pain

Introducción: Los tumores maxilofaciales representan un reto para los anestesiólogos dada la dificultad de controlar el dolor con terapias farmacológicas convencionales. El componente cervical alto del tracto espinomesencefálico y los pares craneales V, VII, IX y X, están involucrados en la fisiopatología del dolor cervicocefálico crónico refractario. Existen estudios que proponen el uso de bajas dosis de bupivacaína a nivel de la cisterna magna como tratamiento de este tipo de dolor con buenos resultados. Nosotros proponemos la asociación de morfina a este nivel con el fin de obtener resultados similares evitando los efectos indeseables derivados de la administración única del anestésico local. Caso clínico: Se trata de una paciente de 41 años sin antecedentes personales de interés salvo ulcus gástrico, diagnosticada de carcinoma epidermoide de suelo de boca en estadio evolutivo avanzado (invasión de ganglios regionales y metástasis laterocervicales), remitida a nuestra consulta por cervicalgia y cefalea intensas. Había seguido tratamiento durante un mes con fentanilo transdérmico 150 µg-h-1 asociado a paracetamol 3 g-24 h-1, metamizol 6 g-24 h-1 y metilprednisolona v.o., a pesar de lo cual mantenía una puntuación en la EVA de 8. Se decide realizar una prueba intradural cervical con 1 mg de morfina y de bupivacaína con resultados satisfactorios. Posteriormente se colocó un catéter intradural cervical, comprobando radiológicamente la ubicación intracisternal de la punta. Se administraron inicialmente bolos de 0,9 mg de morfina y 1,2 mg de bupivacaína cada 12 horas. Con estas dosis se consiguió una disminuir 3 puntos en la EVA en los primeros días. Las dosis se aumentaron semanalmente hasta 3,2 mg y 6,2 mg de morfina y bupivacaína diaria consiguiendo una analgesia satisfactoria (EVA=3). No se observaron efectos adversos salvo ligero prurito e inicialmente náuseas, controlados farmacológicamente. Conclusiones: La administración intracisternal de bupivacaína y morfina puede ser un método útil para el tratamiento del dolor crónico maligno de cabeza y cuello, aunque se necesitarán estudios más completos para establecer tanto indicaciones como la seguridad de dicho método (AU)

Application of ammonia intermittent temperature-programmed desorption to evaluate surface acidity of tungsten oxide supported on activated carbon.

Intermittent temperature-programmed desorption of ammonia was used to study the strength and population of surface acid sites of tungsten oxide supported on activated carbon pretreated at 350 and 700 degrees C. Catalysts pretreated at 350 degrees C showed two types of surface acid sites and desorption occurred with free readsorption until a temperature of around 300 degrees C was reached. Pretreatment at 700 degrees C produced three different states of ammonia adsorbed on the catalysts and desorption occurred with free readsorption.

Tratamiento del dolor y espasticidad en un caso de esclerosis lateral amiotrófica / Management of pain and spasticity in a case of amyotrophic lateral sclerosis

La esclerosis lateral amiotrófica (ELA) es una forma clínica del grupo de enfermedades de la motoneurona del adulto que designa un proceso degenerativo progresivo que aparece de forma esporádica y aislada, aunque se encuentran formas familiares. En cualquier caso es una enfermedad de pronóstico ominoso que se padece durante un promedio de tres años partiendo de los primeros síntomas. Paciente, material y métodos: Paciente de 45 años que en el transcurso de tres meses cursa con sintomatología propia de esclerosis lateral amiotrófica que se confirma con el estudio electromiográfico. Tras respuesta inicial a los antiespásticos por vía oral, con posterioridad resultan insuficientes para el control del dolor y espasticidad a pesar de usar dosis máximas de baclofeno y riluzol vía oral. Por ello se realiza dosis de prueba con morfina y baclofeno intratecal y posteriormente se inicia perfusión continua a través de catéter intratecal de bupivacaína, morfina y baclofeno. Resultados: Después de modificar las pautas de dosificación de morfina, bupivacaína y baclofeno intratecal, se consigue controlar el dolor y espasticidad. Conclusiones: La vía intratecal resulta efectiva en tratamiento del dolor y espasticidad de la ELA después de resultar ineficaz el tratamiento por vía oral. (AU)

[Utilization of a post-anesthetic recovery index]. / Utilización de un índice de recuperación postanestésica.

OBJECTIVES: 1. To introduce use of the postanesthesia recovery score (assessing consciousness, mobility, ventilation, hemodynamics and blood analysis) as a good method for evaluating and classifying recovery from anesthesia in the postoperative care unit. 2. To determine overall patient progress and assess the influence of various patient, anesthetic and surgical factors. PATIENTS AND METHODS: This was a multicenter study of 1,227 patients. We excluded all patients who were to be transferred to intensive care units after surgery. A score of 10 or more, with no single item score equal to 0, was considered optimal for discharge from the postanesthesia care unit. RESULTS: The lowest score upon admission to the unit was among patients who had undergone high abdominal surgery (16.4%). Scores over 9 belonged to patients who had undergone lower abdominal and perineal surgery (87.5 and 95.3%, respectively). Scores were < or = 9 in patients who received inhaled anesthetics (42%). Intravenous anesthesia patients (84.4%) had scores over 9. The local-regional anesthetic procedures with the best scores were axilar blocks and local infiltrations. Patients staying longer in the recovery unit were those classified as ASA III, those whose procedures lasted longer than 120 minutes, those undergoing surgery on the upper abdomen or on extremities, those receiving isoflurane and pancuronium, and those suffering adverse events during and after the procedure. Factors influencing perioperative events were age, duration of procedure and history of intraoperative events.