Application of birnessite-type solids prepared by sol-gel and oxidation methods in photocatalytic degradation of 4-nitrophenol.

Potassium birnessites were prepared using two methods, sol-gel or oxidation. The solids were characterised by element chemical analysis, powder X-ray diffraction, FT-IR spectroscopy, thermal analyses, and nitrogen adsorption. The evolution of the properties as a function of the preparation method was discussed. The photocatalytic performance of these solids was preliminarily tested for the degradation of 4-nitrophenol. The degradation pathway and the nature of the by-products were investigated by mass spectrometry. The solids showed good catalytic behaviour, although their preparation must be improved, mainly concerning the calcination step involved in sol-gel synthesis, which led to the formation of Mn2O3 that worsened the catalytic behaviour.

Effect of the preparation method and metal content on the synthesis of metal modified titanium oxide used for the removal of salicylic acid under UV light.

Titanium dioxide modified with Ag and Fe was synthesized using two preparation methods, characterized and applied to the photocatalytic degradation of salicylic acid in aqueous solution. The modified TiO2 samples were prepared by the sol-gel and wet impregnation methods starting from titanium(IV) isopropoxide and using AgNO3 and Fe(NO3)3·9H2O as precursors of the modifiers, with their content varying between 0 and 5 wt.%. Catalysts characterization was based on powder X-ray diffraction (PXRD), nitrogen physisorption at 77 K, temperature programmed reduction (H2-TPR), chemisorption of NH3 at 343 K and X-ray photoelectron spectroscopy (XPS). The photocatalytic degradation of salicylic acid by modified TiO2 was investigated under ultraviolet irradiation at 298 K considering various concentrations of the catalyst, between 100 and 1000 mgcatalyst/dm3, and of the organic molecule, between 0 and 15 mg/dm3. The catalysts most active in the degradation of salicylic acid were those having the highest Fe content.

Retrospective multicentre observational study on clinical management and treatment of different types of status epilepticus in clinical practice. / Estudio observacional multicéntrico retrospectivo sobre el manejo clínico y terapéutico de los diferentes tipos de estatus epiléptico en la práctica clínica.

INTRODUCTION: Status epilepticus (SE) is a neurological emergency associated with significant mortality and morbidity. We analyse characteristics of this entity in our population. METHODS: Data from electronic medical records of adults diagnosed with SE were collected retrospectively from 5 hospitals over 4 years. RESULTS: Data reflected 84 episodes of SE in 77 patients with a mean age of 60.3 years. Of this sample, 52.4% had a previous history of epilepsy. Status classification: 47.6% tonic-clonic, 21.4% complex partial, 17.9% partial motor, 6% partial simple, 3.6% myoclonic, and 3.6% subtle SE. Based on the duration of the episode, SE was defined in this study as early stage (up to 30min) in 13.1%, established (30-120min) in 20.2%, refractory (more than 120min) in 41.7%, and super-refractory (episodes continuing or recurring after more than 24h of anaesthesia) in 13.1%. Ten patients (11.9%) died when treatment failed to control SE. The cumulative percentage of success achieved was 8.3% with the first treatment, 27.3% for the second, 48.7% for the third, 58.2% for the fourth, 70.1% for the fifth, 80.8% for the sixth, 83.2% for the seventh, and 84.4% for the eighth. CONCLUSIONS: In our study, we found that SE did not respond to treatment within 2h in approximately half the cases and 11.9% of the patients died without achieving seizure control, regardless of the type of status. Half the patients responded by the third treatment but some patients needed as many as 8 treatments to resolve seizures. Using large registers permitting analysis of the different types and stages of SE is warranted.

On the necessity of new decision-making methods for cancer-associated, symptomatic, pulmonary embolism.

BACKGROUND: Acute symptomatic pulmonary embolism (PE) varies in its clinical manifestations in patients with cancer and entails specific issues. The objective is to assess the performance of five scores (PESI, sPESI, GPS, POMPE, and RIETE) and a clinical decision rule to predict 30-day mortality. METHODS: This is an ambispective, observational, multicenter study that collected episodes of PE in patients with cancer from 13 Spanish centers. The main criterion for comparing scales was the c-indices and 95% confidence intervals (CIs) of the models for predicting 30-day mortality. RESULTS: 585 patients with acute symptomatic PE were recruited. The 30-day mortality rate was 21.3 (95% CI; 18.2-24.8%). The specific scales (POMPE-C and RIETE) were equally effective in discriminating prognosis (c-index of 0.775 and 0.757, respectively). None of these best performing scales was superior to the ECOG-PS with a c-index of 0.724. The remaining scores (PESI, sPESI, and GPS) performed worse, with c-indexes of 0.719, 0.705, and 0.722, respectively. The dichotomic "clinical decision rule" for ambulatory therapy was at least equally reliable in defining a low risk group: in the absence of all exclusion criteria, 30-day mortality was 2%, compared to 5% and 4% in the POMPE-C and RIETE low-risk categories, respectively. CONCLUSION: The accuracy of the five scales examined was not high enough to rely on to predict 30-day mortality and none of them contribute significantly to qualitative clinical judgment.

Functional lateralization of the medial prefrontal cortex in the modulation of anxiety in mice: Left or right?

It has been suggested that the left medial prefrontal cortex (LmPFC) has an inhibitory role in controlling the right mPFC (RmPFC), thereby reducing the deleterious effects of stressors on emotional states. Here, we investigated the effects on anxiety of bilateral or unilateral injections of NOC-9 [a nitric oxide (NO) donor] and cobalt chloride (CoCl2; a synaptic inhibitor) into the mPFC of mice exposed to the elevated plus-maze (Experiments 1 and 2). The effects of restraint or social defeat on anxiety in undrugged mice were recorded at 5 min or 24 h after exposure to the stress (Experiment 3). Experiment 4 investigated the effects of LmPFC injection of CoCl2 combined with restraint or social defeat on anxiety, which was recorded 24 h later. Although intra-RmPFC NOC-9 produced anxiogenesis, its injection into the LmPFC, or bilaterally, did not change anxiety. Intra-RmPFC or -LmPFC injection of CoCl2 produced anxiolytic- and anxiogenic-like effects, respectively. Both restraint and social defeat produced anxiogenesis at 5 min, but defeated mice did not display anxiety 24 h after the stress. Although intra-LmPFC CoCl2 did not change anxiety, which was recorded 24 h later in non-stressed mice, this synaptic inhibitor produced a clear, anxiogenic-like effect in defeated (but not restrained) mice. These results suggest that (i) nitrergic activation of the RmPFC increases anxiety, which in turn is inhibited by NO production within the LmPFC; (ii) neuronal inhibition of the RmPFC or LmPFC elicits anxiolysis and anxiogenesis, respectively; and (iii) inactivation of the LmPFC results in recrudescence of anxiety induced by social defeat stress.

Información, comunicación y trato en un servicio de urgencias: evaluación mediante una encuesta de opinión / Opinion survey on information, communication and treatment in an Emergency Department

Objetivo. Conocer aspectos concretos acerca de la información y la comunicación con los usuarios de los servicios de urgencias hospitalarias y el trato recibido en ellos a través de una encuesta telefónica. Métodos. Estudio prospectivo en 2 servicios de urgencias hospitalarias de Salamanca. Se incluyeron en el estudio 400 pacientes (edad media 56,4 ± 20,5 años; 58,4% mujeres). Se realizó una encuesta telefónica con 19 ítems. Doce de ellos recogían las respuestas en escala tipo Likert, con puntuaciones de 1 (muy mal) a 5 (muy bien). El resto permitían responder «sí» o «no». Resultados. El 86% de los pacientes evaluaron positivamente el trato recibido por los profesionales en general, el 92% el respeto mostrado, el 87% el trato de los médicos y el 71% el trato recibido por enfermería. El 27,5% no recuerda haber recibido información del personal del punto azul (profesionales especialmente capacitados para dar información). Se encontró significación estadística (p = 0,045) en relación a la amabilidad y respeto mostrado por enfermería. La mayoría de los pacientes que fueron ingresados en el área de observación del servicio de urgencias no fueron informados sobre los horarios de visita (p = 0,003). Conclusiones. La percepción del trato recibido por los pacientes es buena, mientras que en relación a la información y comunicación es ostensiblemente mejorable y podría ser evaluada utilizando la encuesta que proponemos, ya que permite detectar y utilizar los puntos débiles de estos aspectos de la asistencia sanitaria como lanzaderas de las iniciativas de implementación (AU)

Objective. To gather specific details about the information, communication, and treatment as regards users of hospital emergency services using a telephone survey, in order to implement improvement measures, if necessary. Methods. A prospective study was conducted in two emergency departments in Salamanca. A total of 400 patients were included in the study (mean age 56.4 ± 20.5 years, 58.4% women). A telephone survey was performed with 19 items, of which 12 required responses on a Likert-type scale, with scores of 1 (very bad) to 5 (very good). The remainder of the questions allowed to answer 'yes' or 'no'. Results. The treatment received by the professionals in general was evaluated positively by 86% of the patients; with 92% reporting they were respectful, 87% were treated by doctors and 71% received treatment from nurses. More than one-quarter (27.5%) did not recall receiving information from blue point staff (personnel specially trained to provide information. Statistical significance (P = .045) was found in relation to the kindness and respect shown by nurses. Most patients that were admitted to the observation area of the emergency department were not informed about the visiting hours (P = .003). Conclusions. Perception of care received by patients is good, while in relation to information and communication it is evidently improvable, and could be assessed using the survey that is proposed in order to detect and use the weaknesses in these aspects of health care as implementation initiatives (AU)

[Opinion survey on information, communication and treatment in an Emergency Department]. / Información, comunicación y trato en un servicio de urgencias: evaluación mediante una encuesta de opinión.

OBJECTIVE: To gather specific details about the information, communication, and treatment as regards users of hospital emergency services using a telephone survey, in order to implement improvement measures, if necessary. METHODS: A prospective study was conducted in two emergency departments in Salamanca. A total of 400 patients were included in the study (mean age 56.4±20.5years, 58.4% women). A telephone survey was performed with 19 items, of which 12 required responses on a Likert-type scale, with scores of 1 (very bad) to 5 (very good). The remainder of the questions allowed to answer "yes" or "no". RESULTS: The treatment received by the professionals in general was evaluated positively by 86% of the patients; with 92% reporting they were respectful, 87% were treated by doctors and 71% received treatment from nurses. More than one-quarter (27.5%) did not recall receiving information from blue point staff (personnel specially trained to provide information. Statistical significance (P=.045) was found in relation to the kindness and respect shown by nurses. Most patients that were admitted to the observation area of the emergency department were not informed about the visiting hours (P=.003). CONCLUSIONS: Perception of care received by patients is good, while in relation to information and communication it is evidently improvable, and could be assessed using the survey that is proposed in order to detect and use the weaknesses in these aspects of health care as implementation initiatives.

Discovering less toxic ionic liquids by using the Microtox® toxicity test.

New Microtox® toxicity data of 16 ionic liquids of different cationic and anionic composition were determined. The ionic liquids 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate, [BMPyr(+)][TFO(-)], 1-butyl-1-methylpyrrolidinium chloride, [BMPyr(+)][Cl(-)], hydroxypropylmethylimidazolium fluoroacetate, [HOPMIM(+)][FCH2COO(-)], and hydroxypropylmethylimidazolium glycolate [HOPMIM(+)][glycolate(-)] were found to be less toxic than conventional organic solvent such as chloroform or toluene, accoding the Microtox® toxicity assays. The toxicity of pyrrolidinium cation was lower than the imidazolium and pyridinium ones. It was found that the inclusion of an hydroxyl group in the alkyl chain length of the cation also reduce the toxicity of the ionic liquid. To sum up, the Microtox® toxicity assays can be used as screening tool to easily determined the toxicity of a wide range of ionic liquids and the toxicity data obtained could allow the obtention of structure-toxicity relationships to design less toxic ionic liquids.

[Surgical treatment of giant congenital melanocytic nevi: a change of aim]. / Tratamiento quirúrgico del nevus melanocítico gigante: un cambio de objetivo.

OBJECTIVE: To review the surgical experience in Giant Congenital Melanocytic Nevi (GCMN). MATERIAL AND METHODS: Review of GCMN cases consulting at the Department of Pediatric Surgery since 1994. Data registered were: year and age at 1st consultation, type of treatment, number of surgical procedures and complications, histology, central nervous system MRI and follow-up. RESULTS: Eleven patients with GCMN > 10% of body surface consulted at ages ranging from newborn to 8 years. All of them had multiple surgical procedures (2-19), from nevus removal to only biopsies. Eight patients had tissue expansion, completed in 3 of them with skin grafts on dermal substitute. Six patients had complications: 4 expander extrusions, 5 infections, 3 flap necrosis and 1 dehiscence. In 6 children a total or subtotal resection of the nevus was achieved; in 2 the treatment was interrupted, remaining 20% and 50% of the initial nevus; three patients had not had nevus treatment. None of the patients presented cutaneous melanoma; one died from intracranial melanoma; another one has leptomeningeal melanosis. The first 4 patients underwent an average of 16 surgical procedures each, the last 7 patients only 5. CONCLUSIONS: The aim of GCNM management has changed: GCNM treatment is now surgically conservative. Complete excision is now not the aim when technically unfeasible in few procedures; multiple surgical procedures with poor cosmetical results are not acceptable. The gravity is determined by CNS involvement.

Quality measures in neurology consult care for epileptic patients.

INTRODUCTION: Epilepsy is one of the most frequently observed diseases in neurology outpatient care. METHODS: We analysed our hospital's implementation of the 8 epilepsy quality measures proposed by the American Academy of Neurology: documented seizure types and seizure frequency, aetiology of epilepsy or the epilepsy syndrome, review of EEG, MRI, or CT results, counselling about antiepileptic drug side effects, surgical therapy referral for intractable epilepsy, and counselling about epilepsy-specific safety issues and for women of childbearing age. RESULTS: In most cases, the first four quality measures were documented correctly. In 66% of the cases, doctors had asked about any adverse drug effects during every visit. Almost all patients with intractable epilepsy had been informed about surgical options or referred to a surgical centre of reference for an evaluation at some point, although referrals usually took place more than 3 years after the initial proposal. Safety issues had been explained to 37% of the patients and less than half of women of childbearing age with epilepsy had received counselling regarding contraception and pregnancy at least once a year. CONCLUSIONS: The care we provide is appropriate according to many of the quality measures, but we must deliver more counselling and information necessary for the care of epileptic patients in different stages of life.

Dynamics of water in synthetic saponite clays: effect of trivalent ion substitution.

Saponite clay belongs to the phyllosilicate family and is comprised of layers of Si(IV) tetrahedra and Al(III) or Mg(II) octahedra with definite interlayer spacing. In these systems, the trivalent ion substitutions in the tetrahedral layers lead to negative charge on the layers. Here we report the dynamics of water contained in [Si(6.97)Al(1.03)][Ni(6.00)]O(20)(OH)(4)[Na(1.03)]·28H(2)O (SAP-1) and [Si(7.13)Fe(0.86)][Ni(6.00)]O(20)(OH)(4)[Na(0.86)]·14H(2)O (SAP-2) saponite clays in the temperature range 200-310 K as studied by quasielastic neutron scattering technique. Particularly the effect of the ion substitution towards the dynamics of water is addressed here. Data analysis is carried out using the relaxing cage model. The existence of distribution in relaxation times indicated that the water molecules in saponite clay have a different local environment which leads to complex diffusion behavior. It is found that water exists in a supercooled state in the temperature range up to 235 K. However, some of the water molecules are found to be immobile in the temperature range 240-285 K. The fraction of immobile water decreases with increase in temperature. At higher temperatures, some of the water molecules in the hydration shells or those near the surface start participating in the diffusion process and at 293 K, almost all water molecules contribute to the dynamics. Diffusivity of water in both SAP-1 and SAP-2 are found to be lower in comparison to the bulk, and within the two samples of saponite clay diffusivity in SAP-1 is found to be lower compared to SAP-2; this has been explained on the basis of the charge on the tetrahedral layers and the charge balancing cations in the interlayer spacing.

Characterization of a sulfadiazine-induced lithiasis calculus by physicochemical techniques.

Currently available information on drug lithiasis usually describes the calculi based on the prescriptions given to the patient, but without a physicochemical characterization of the calculi themselves. We here have applied different, complementary, physicochemical techniques for a complete characterization of an unusual urolithiasis calculus. The calculus was characterized using powder X-ray diffraction, infrared spectroscopy, mass spectrometry, 1H-NMR spectroscopy, and scanning electron microscopy. The precise nature of the calculus was identified, being formed by N4-acetylsulfadiazine, so being related to the drugs prescribed to the patient. Analytical techniques widely used in laboratories of Materials Chemistry have proven to be useful tools for characterizing the chemical nature of unusual urolithiasis.

Porokeratotic eccrine ostial and dermal duct naevus: report of 10 cases.

BACKGROUND: Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is a congenital hamartoma that has rarely been documented. OBJECTIVES: To describe the clinical and histological features of 10 patients with PEODDN. METHODS: A retrospective study of 10 patients with PEODDN attended in our paediatric hospital between 1999 and 2009 was performed. The clinical and histopathological features were reviewed. RESULTS: Nine children and one adult were included in the study. In 6 cases the lesion was present at birth and they were unique in 5 cases and systematized in the other 5 cases. Two cases in the same family are reported. The lesions were most commonly found on the extremities, although the palms or soles were involved in 9 cases and only in one case there was not affection of this area. The lesions were mostly asymptomatic but there was moderate itching in two cases. Clinical examination revealed no extracutaneous involvement. CONCLUSIONS: PEODDN is a rare disorder that usually appears at birth or early childhood. It has a linear distribution following the Blaschko lines. To our knowledge this is the largest series reported in English literature and we also describe the first family case.

Phenol degradation in water through a heterogeneous photo-Fenton process catalyzed by Fe-treated laponite.

New photo-Fenton catalysts have been prepared from synthetic layered clay laponite (laponite RD). Two series of Fe-laponite catalysts were synthesised, with or without thermal treatment of the mixture Fe polycations-laponite in the intercalation procedure. In each series, the intercalated solids underwent calcination at four temperatures, 250, 350, 450, and 550 degrees C. The catalysts were used for photo-assisted Fenton conversion of phenol, analyzing the influence of five operating factors: the wavelength of the light source (254 nm UV-C and 360 UV-A radiation), the amount of the catalyst (between 0 and 2 g/L), the initial phenol concentration (between 0.5 and 1.5 mmol/L), the initial concentration of hydrogen peroxide (between 20 and 100 mmol/L), and the initial pH of the solution (between 2.5 and 3.5). In all experiments, the temperature was kept constant at 30 degrees C. The results have shown that the almost complete conversion of phenol was possible, after only 5 min, under the following operating conditions: UV-C radiation; a pH of the aqueous solution of 3; a dose of 1 g(catalyst)/L, and a hydrogen peroxide concentration of 50 mmol/L for a solution containing 1 mmol/L of phenol. The catalyst prepared under thermal treatment and calcined at 350 degrees C showed the best catalytic performance. A kinetic model was proposed for the process, testing its validity and estimating the rate constants.

Multiplicação in vitro e aclimatação de Vernonia condensata Baker / In vitro multiplication and acclimation of Vernonia condensata Baker

A espécie medicinal Vernonia condensata, vulgarmente conhecida por alumã, pertencente à família Asteraceae, possui propriedades analgésicas e de proteção gástrica. A crescente utilização dessa planta no Nordeste, pelas propriedades terapêuticas, justifica a necessidade de medidas que minimizem o impacto de sua exploração nas reservas naturais. O objetivo desse trabalho foi multiplicar in vitro plantas de alumã sob diferentes concentrações de BAP e aclimatá-las. Gemas axilares foram desinfestadas em solução de álcool etílico 70 por cento, durante 2 minutos e em solução de hipoclorito de sódio (2 por cento de cloro ativo) na concentração de 3:1, durante 15 minutos, seguido de três lavagens em água destilada estéril. Os tratamentos para multiplicação consistiram em doses de BAP (0,0; 1,0; 2,0; 3,0; 4,0 e 5,0 mg L-1) em meio MS semi-sólido. O delineamento experimental foi o inteiramente casualizado, com 5 repetições, contendo 10 gemas por repetição. Após 30 dias de cultivo observou-se maior taxa de explantes responsivos, 84 por cento na concentração de 1,0 mg L-1 de BAP, com produção de 4,0 brotos/explante. Nos tratamentos 3,0; 4,0 e 5,0 mg L-1 ocorreu hiperhidricidade nas folhas. As microplantas de alumã provenientes da metodologia utilizada neste trabalho alcançaram 100 por cento de sobrevivência na aclimatação.

The medicinal species Vernonia condensata, commonly known as "alumã", belongs to the family Asteraceae and has analgesic and gastric protective properties. The increasing use of this plant in the Northeast of Brazil due to its therapeutic properties justifies the need of measures to minimize the impact of its exploitation in natural reserves. The aim of this study was to multiply, in vitro, "alumã" plants under different BAP levels, acclimating them. Axillary buds were sterilized in 70 percent (v/v) alcohol solution for 2 minutes and in 75 percent sodium hypochlorite solution (2 percent active chlorine) at 3:1 concentration for 15 minutes, followed by three washings in sterile distilled water. Multiplication treatments consisted of different BAP levels (0.0; 1.0; 2.0; 3.0; 4.0 and 5.0 mg L-1) in semi-solid MS medium. The experimental design was completely randomized, with 5 replicates and 10 buds per replicate. After 30 days of cultivation, the highest rate of responsive explants was obtained: 84 percent at 1.0 mg L-1 BAP, producing 4.0 sprouts/explant. In the treatments 3.0, 4.0 and 5.0 mg L-1, there were vitrified leaves. The "alumã" microplants used in this study had 100 percent survival in acclimation.

Magnetic properties of nickel and cobalt catalysts supported on nanoporous oxides.

The aim of this work is to use magnetic measurements as a research tool in the study of possible metal-support interactions in nickel and cobalt nanoporous catalysts. Several physicochemical techniques, namely nitrogen adsorption, X-ray diffraction, temperature-programmed reduction and chemical analysis, were used to analyze the role of the preparation method and the nature of the support on the existence of such metal-support interactions and to relate them with the magnetic response of these nanoporous systems. The catalysts were prepared by incipient wetness impregnation and precipitation-deposition with two commercial oxides, gamma-Al2O3 and SiO2, as supports. The magnetic behavior of the catalysts is drastically affected by the existence of interactions between the metal and the support during the preparation procedure. The samples with weak metal-support interactions have characteristic magnetic behavior of antiferromagnetic metal oxide nanoparticles, while the ones having strong interactions display spin-glass like behavior.

[Neurotransmitters in Alzheimer's disease]. / Neurotransmisores en la enfermedad de Alzheimer.

AIM: To review the current state of the art in neurotransmission in Alzheimer's disease (AD) and its involvement in the pathophysiology of the disease. INTRODUCTION: AD is a neurodegenerative disorder that is estimated to affect 15 million people around the world. Since the cholinergic hypothesis of AD was put forward 20 years ago, numerous studies have been conducted in an attempt to determine the role that neurotransmitters play in AD. Among other things, this has made it possible to develop drugs based on the inhibition of acetylcholinesterase. DEVELOPMENT: The monoaminergic neurotransmission systems are examined, with special attention given to the cholinergic system, and their anatomical distribution, function, receptors, activity and degradation systems are also described. Peptidergic neurotransmission systems are only briefly discussed, since they are not the main objective of this report. We also review the cholinergic hypothesis and the possible interrelations between cholinergic neurotransmission and beta-amyloid metabolism, as well as the potential involvement of acetylcholinesterase inhibitor drugs in more fundamental pathophysiological mechanisms, which act with a neuroprotective component.

Neurotransmisores en la enfermedad de Alzheimer / Neurotransmitters in Alzheimer’s disease

Objetivo. Revisar el estado actual de los conocimientos sobre la neurotransmisión en la enfermedad de Alzheimer (EA) y su implicación en la fisiopatología de la enfermedad. Introducción. La EA es un trastorno neurodegenerativo que se estima que afecta a 15 millones de personas en todo el mundo. Desde que se postuló hace 20 años la hipótesis colinérgica de la EA, se han realizado múltiples estudios para intentar conocer el papel que desempeñan los neurotransmisores en la EA. Entre otras cosas, esto ha permitido el desarrollo de fármacos basados en la inhibición de la acetilcolinesterasa. Desarrollo. Se revisan los sistemas de neurotransmisión monoaminérgicos, con especial atención en el sistema colinérgico, describiendo su distribución anatómica, función, receptores, actividad y sistemas de degradación. Se citan brevemente, ya que no es el objetivo primario de esta revisión, los sistemas de neurotransmisión peptidérgicos y se revisan la hipótesis colinérgica y las posibles interrelaciones entre la neurotransmisión colinérgica y el metabolismo del b-amiloide, así como la posible implicación de los fármacos inhibidores de la acetilcolinesterasa en mecanismos fisiopatológicos más básicos, con un componente neuroprotector (AU)

Aim. To review the current state of the art in neurotransmission in Alzheimer’s disease (AD) and its involvement in the pathophysiology of the disease. Introduction. AD is a neurodegenerative disorder that is estimated to affect 15 million people around the world. Since the cholinergic hypothesis of AD was put forward 20 years ago, numerous studies have been conducted in an attempt to determine the role that neurotransmitters play in AD. Among other things, this has made it possible to develop drugs based on the inhibition of acetylcholinesterase. Development. The monoaminergic neurotransmission systems are examined, with special attention given to the cholinergic system, and their anatomical distribution, function, receptors, activity and degradation systems are also described. Peptidergic neurotransmission systems are only briefly discussed, since they are not the main objective of this report. We also review the cholinergic hypothesis and the possible interrelations between cholinergic neurotransmission and β-amyloid metabolism, as well as the potential involvement of acetylcholinesterase inhibitor drugs in more fundamental pathophysiological mechanisms, which act with a neuroprotective component (AU)

Effect of the platinum content on the microstructure and micropore size distribution of Pt/alumina-pillared clays.

The aim of this work is to study the effect of the platinum content (0-1.8 wt % Pt) on the microstructure of an alumina-pillared clay. For this purpose, the nitrogen physisorption data at -196 degrees C, the micropore size distributions of the supported platinum catalysts, and the hydrogen chemisorption results at 30 degrees C have been analyzed and compared. The preparation of the catalysts has modified the textural properties of the Al-pillared clay support, giving rise to a loss of surface area and micropore volume. After reduction at 420 degrees C, the presence of dispersed metallic platinum with mean crystallite size in the 22-55 A range has been found by hydrogen adsorption. Comparison of all results reveals that the platinum species block the micropore entrances by steric hindrance to nitrogen access as the platinum content increases.