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Evaluation of the ability of arsenic species to traverse cell membranes by simple diffusion using octanol-water and liposome-water partition coefficients

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Journal of Environmental Sciences 2016年第11期28卷 222-232页

作者： Teresa Chavez-capilla William Maher Tamsin Kelly Simon Foster Ecochemistry Laboratory Institute for Applied Ecology University of Canberra Canberra ACT 2601 Australia National Centre for Forensic Studies Faculty of Education Science Technology and Mathematics University of Canberra CanberraACT 2601 Australia

Arsenic metabolism in living organisms is dependent on the ability of different arsenic species to traverse biological membranes. Simple diffusion provides an alternative influx and efflux route to mediated transport mechanisms that can increase the amount of arsenic available for metabolism in cells. Using octanol-water and liposome-water partition coefficients, the ability of arsenous acid, arsenate, methylarsonate, dimethylarsinate, thio-methylarsonate, thiodimethylarsinic acid, arsenotriglutathione and monomethylarsonic diglutathione to diffuse through the lipid bilayer of cell membranes was investigated. Molecular modelling of arsenic species was used to explain the results. All arsenic species with the exception of arsenate, methylarsonate and thio-methylarsonate were able to diffuse through the lipid bilayer of liposomes, with liposome-water partition coefficients between 0.04 and 0.13. Trivalent arsenic species and thio-pentavalent arsenic species showed higher partition coefficients, suggesting that they can easily traverse cell membranes by passive simple diffusion. Given the higher toxicity of these species compared to oxo-pentavalent arsenic species, this study provides evidence supporting the risk associated with human exposure to trivalent and thio-arsenic species.

关键词： ArsenicLiposomesPartition coefficientsPassive simple diffusionTrivalent arsenic speciesThio-arsenic species

Application of Statistical Methods to Assess Carbon Monoxide Pollution Variations within an Urban Area

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International Journal of Geosciences 2012年第5期3卷 885-890页

作者： Carmen capilla Department of Applied Statistics and Operations Research and Quality Universidad Politécnica de Valencia Valencia Spain

In recent years there have been considerable new legislation and efforts by vehicle manufactures aimed at reducing pollutant emission to improve air quality in urban areas. Carbon monoxide is a major pollutant in urban areas, and in this study we analyze monthly carbon monoxide (CO) data from Valencia City, a representative Mediterranean city in terms of its structure and climatology. Temporal and spatial trends in pollution were recorded from a monitoring net- work that consisted of five monitoring sites. A multiple linear model, incorporating meteorological parameters, annual cycles, and random error due to serial correlation, was used to estimate the temporal changes in pollution. An analysis performed on the meteorologically adjusted data reveals a significant decreasing trend in CO concentrations and an annual seasonal cycle. The model parameters are estimated by applying the least-squares method. The standard error of the parameters is determined while taking into account the serial correlation in the residuals. The decreasing trend im- plies to a certain extent an improvement in the air quality of the study area. The seasonal cycle shows variations that are mainly associated with traffic and meteorological patterns. Analysis of the stochastic spatial component shows that most of the intersite covariances can be analyzed using an exponential variogram model.

关键词： Carbon Monoxide Monitoring Network Statistical Model Urban Air Pollution

Assessment of Saltwater Intrusion and Discharges to a Wetland with a 3D Transient Variable Density Flow Model: The Coastal Plane Oropesa-Torreblanca Aquifer, Spain

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Journal of Water Resource and Protection 2015年第9期7卷 749-768页

作者： Ignacio Sanz-Garrido José E. capilla Research Institute of Water and Environmental Engineering Universitat Politécnica de Valencia Valencia Spain

The proper characterization of coastal aquifers requires modeling variable density flow effects. However, most models estimate processes as saline intrusion based on 2D models with constant density and are rarely calibrated to honor salinity measurements. These facts limit the model predictions reliability, affecting the estimated hydrodynamic parameters, external stresses, and other model outputs that can be critical for planning or management decisions. This paper describes the re-assessment of a coastal aquifer model (Oropesa-Torreblanca, eastern Spain) subjected to moderate-to-high saline intrusion with a transient 3D variable density flow model. Previous models were based on 2D low-resolution grids without variable density effects. The new model honors the observed trends of both piezometric and salinity data. Results show the importance of the variable density effects having on critical outputs as sea intrusion and the discharges to a local wetland of high environmental value. The widespread intrusion process and its current stabilization are confirmed but, compared to previous models, the annual average intrusion is 156% higher, discharge to the wetland increases 30%, and the inflows from neighboring formations increase 22%. The more accurate aquifer models, as well as the new discharges and intrusion estimations, are important contributions for future water and environmental planning decisions in the area.

关键词： Salinization Intrusion Variable Density Calibration Wetland

Wireless capsule endoscopy: Perspectives beyond gastrointestinal bleeding

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World Journal of Gastroenterology 2014年第42期20卷 15664-15673页

作者： Eduardo Redondo-Cerezo Antonio Damián Sánchez-capilla Paloma De La Torre-Rubio Javier De Teresa Endoscopy Unit Department of Gastroenterology University Hospital Virgen de Las Nieves Department of Gastroenterology University Hospital Virgen de Las Nieves

Wireless capsule endoscopy(CE) is a technology developed for the endoscopic exploration of the small bowel. The first capsule model was approved by the Food and Drug Administration in 2001, and its first and essential indication was occult gastrointestinal(GI) bleeding. Over subsequent years, this technology has been refined to provide superior resolution, increased battery life, and capabilities to view different parts of the GI tract. Indeed, cases for which CE proved useful have increased significantly over the last few years, with new indications for the small bowel and technical improvements that have expanded its use to other parts of the GI tract, including the esophagus and colon. The main challenges in the development of CE are new devices with the ability to provide therapy, air inflation for a better vision of the small bowel, biopsy sampling systems attached to the capsule and the possibility to guide and move the capsule with an external motion control. In this article we review the current and new indications of CE, and the evolving technological changes shaping this technology, which has a promising potential in the coming future of gastroenterology.

关键词： Wireless capsule endoscopy Obscure gas-trointestin

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World Journal of Gastroenterology 2013年第30期19卷 4877-4886页

作者： María Gómez-García Maria José Cabello-Tapia Antonio Damián Sánchez-capilla Javier De Teresa-Galván Eduardo Redondo-Cerezo Inflammatory Bowel Disease Unit Department of GastroenterologyUniversity Hospital Virgen de Las Nieves18014 GranadaSpain Department of Gastroenterology University Hospital Virgen de Las Nieves18014 GranadaSpain Endoscopy Unit Department of GastroenterologyUniversity Hospital Virgen de Las Nieves18014 GranadaSpain

AIM:To investigate the incidence of neoplasms in inflammatory bowel disease(IBD)patients and the potential causative role of ***:We performed an observational descriptive study comparing the incidence of malignancies in IBD patients treated with thiopurines and patients not treated with these *** included 812 patients which were divided in two groups depending on whether they have received thiopurines or *** have studied basal characteristics of both groups(age when the disease was diagnosed,sex,type of IBD,etc.)and treatments received(Azathioprine,mercaptopurine,infliximab,adalimumab or other immunomodulators),as well as neoplasms *** analysis was performed with the student t test,χ 2 test or Wilcoxon exact test as appropriate.A logistic regression analysis was performed as multivariate *** significance was establish at P values of less than 0.05,and 95%CI were used for the odds ***:Among 812 patients included,429(52.83%)have received thiopurines:79.5% azathioprine,14% mercaptopurine and 6.5% both drugs.44.76% of patients treated with thiopurines and 46,48% of patients who did not receive this treatment were women(P > 0.05).The proportion of ulcerative colitis patients treated with thiopurines was 30.3% compare to 66.67% of patients not treated(P < 0.001).Mean azathioprine dose was 123.79 ± 36.5 mg/d(range:50-250 mg/d),mean usage time was 72.16 ± 55.7 mo(range:1-300 mo)and the accumulated dose along this time was 274.32 ± 233.5 g(1.5-1350 g).With respect to mercaptopurine,mean dose was 74.7 ± 23.9 mg/d(range:25-150 mg/d),mean usage time of 23.37 ± 27.6 mo(range:1-118 mo),and the accumulated dose along this time was 52.2 ± 63.5 g(range:1.5-243 g).Thiopurine S-methyltransferase activity was tested in 66% of patients treated with thiopurines,among which 98.2% had an intermediate or high *** the patients treated with thiopurines,27.27%(112 patients)and 11.66%(50 patients)received treatment

关键词： Malignancy Neoplasm Inflammatory bowel disease Crohn’s disease Ulcerative colitis Thiopurines Azathioprine Mercaptopurine

New insights to occult gastrointestinal bleeding: From pathophysiology to therapeutics

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World Journal of Gastrointestinal Pathophysiology 2014年第3期5卷 271-283页

作者： Antonio Damián Sánchez-capilla Paloma De La Torre-Rubio Eduardo Redondo-Cerezo Department of Gastroenterology University Hospital Virgende Las Nieves 18014 Granada Spain Department of Gastroenterology University Hospital Virgen deLas Nieves 18014 Granada Spain Endoscopy Unit Department of Gastroenterology University Hospital Virgen de Las Nieves 18014 Granada Spain

Obscure gastrointestinal bleeding is still a clinical challenge for gastroenterologists. The recent development of novel technologies for the diagnosis and treatment of different bleeding causes has allowed a better management of patients, but it also determines the need of a deeper comprehension of pathophysiology and the analysis of local expertise in order to develop a rational management algorithm. Obscure gastrointestinal bleeding can be divided in occult, when a positive occult blood fecal test is the main manifestation, and overt, when external sings of bleeding are visible. In this paper we are going to focus on overt gastrointestinal bleeding, describing the physiopathology of the most usual causes, analyzing the diagnostic procedures available, from the most classical to the novel ones, and establishing a standard algorithm which can be adapted depending on the local expertise or availability. Finally, we will review the main therapeutic options for this complex and not so uncommon clinical problem.

关键词： Obscure gastrointestinal bleeding Angiodysplasia Wireless capsule endoscopy Double balloon enteroscopy