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Search Results: 1 - 10 of 209637 matches for " Octavio López-Albors "
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Effect of double-balloon enteroscopy on pancreas: An experimental porcine model
Rafael Latorre,Federico Soria,Octavio López-Albors,Ricardo Sarriá
World Journal of Gastroenterology , 2012, DOI: 10.3748/wjg.v18.i37.5181
Abstract: AIM: To evaluate the effect of double-balloon enteroscopy (DBE) on pancreas histology and levels of pancreatic enzymes. METHODS: Conventional upper gastrointestinal endoscopy was performed on five control pigs. Oral DBE was performed with an EN-450T5 enteroscope on 20 pigs. Two experimental groups (10 pigs each) were defined according to DBE duration: 90 min for Group 1 and 140 min for Group 2. During oral insertion, the balloons were not inflated in the descending part of the duodenum to avoid the minor duodenal papilla. Serum amylase, lipase and C-reactive protein (CRP) levels were monitored before the procedure and repeated every 30 min until the exploration was finished, as well as 24 h and 7 d after. After the procedure and for a total of 7 d, the pigs were observed twice a day for signs of decreased activity, irritability, vomiting or anorexia. Gross and microscopic examination of the pancreas was performed on day 7. RESULTS: All animals tolerated DBE without clinical manifestations of acute pancreatitis. Experimental groups had higher levels of enzymes than the control group at 24 h. Throughout the exploration, the amylase levels increased significantly above the baseline 24 h after DBE, although the increase was not statistically significant and did not reach 20% of the baseline. An increase in lipase and CRP was observed at 24 h after the procedure, although by day 7, all enzymatic levels had returned to baseline. No differences between Groups 1 and 2 were found for any enzyme and sampling site during and after the procedure. Similarly, no correlation between insertion depth and enzyme levels was observed. Direct in situ and post-removal inspection of the pancreas did not show any evidence of fluid collection, abscesses or hemorrhage. Histological examination of the pancreas from Groups 1 and 2 revealed the existence of focal areas (0.14-0.26 mm2) of ischemic necrosis in 47.4% of the animals. In the pigs with damaged pancreas, the left lobe (tail) was always affected. However, this only happened in 83.3% of the samples from the right lobe (head) and in 33.3% of the samples from the body of the pancreas. Significant differences were found between the left lobe (tail) and the body for the percentage of affected pancreas. Both the size of the lesions and the percentage of affected pancreas were higher in the left pancreatic lobe (tail). The presence of the lesions was not related to the exploration length. CONCLUSION: The increase in pancreatic enzymes after DBE could be related to focal points of pancreatic ischemic necrosis due to mechanical str
Evaluation of Wedged Arterial Injection as a New Technique for Delivery of Experimental Therapeutic Sustances into the Porcine Pancreas
Rafael Latorre,Wendy Hernández,Fei Sun,Francisco Sánchez-Margallo,Francisco Gil,Octavio López-Albors,Jose M. Vázquez,Jesús Usón
Experimental Diabetes Research , 2011, DOI: 10.1155/2011/976910
Abstract: Objectives. To prospectively evaluate the technical feasibility and efficacy of wedged arterial injection (WAI) as a potential route for experimental selective therapy to the pancreas of healthy pigs. Materials and Methods. Selective angiographies were completed in ten pigs under general anaesthesia. By superselective angiography, the catheter was inserted and wedged into the major pancreatic artery, blocking the blood flow. In order to evaluate the efficacy of the WAI method, a DNA-specific fluorescent dye (Hoechst 33258) was used. Results. Histological study revealed a uniform distribution of the fluorescent dye within the nuclei of the endocrine and exocrine pancreatic cells. Pancreatic and liver enzymes as well as histopathology of the pancreas were normal. Conclusion. WAI is a highly effective minimally invasive methodology to target the porcine pancreas. The findings suggest that WAI may contribute to developing preclinical assays of pancreas gene or cell-transfer therapies in swine model.
Evaluation of Wedged Arterial Injection as a New Technique for Delivery of Experimental Therapeutic Sustances into the Porcine Pancreas
Rafael Latorre,Wendy Hernández,Fei Sun,Francisco Sánchez-Margallo,Francisco Gil,Octavio López-Albors,Jose M. Vázquez,Jesús Usón
Journal of Diabetes Research , 2011, DOI: 10.1155/2011/976910
Abstract: Objectives. To prospectively evaluate the technical feasibility and efficacy of wedged arterial injection (WAI) as a potential route for experimental selective therapy to the pancreas of healthy pigs. Materials and Methods. Selective angiographies were completed in ten pigs under general anaesthesia. By superselective angiography, the catheter was inserted and wedged into the major pancreatic artery, blocking the blood flow. In order to evaluate the efficacy of the WAI method, a DNA-specific fluorescent dye (Hoechst 33258) was used. Results. Histological study revealed a uniform distribution of the fluorescent dye within the nuclei of the endocrine and exocrine pancreatic cells. Pancreatic and liver enzymes as well as histopathology of the pancreas were normal. Conclusion. WAI is a highly effective minimally invasive methodology to target the porcine pancreas. The findings suggest that WAI may contribute to developing preclinical assays of pancreas gene or cell-transfer therapies in swine model. 1. Introduction Animal models are essential tools for investigating the aetiology and pathogenesis of diabetes as well as for developing effective treatment methods, such as islet transplantation or genetic engineering [1, 2]. Although a range of well-characterized and widely used models of type 1 diabetes in rodents are currently available, they do not reliably predict therapeutic outcomes in larger mammals [2–4]. Large animal models are a valuable complement to rodents for both physiological and practical reasons. Anatomically, the porcine and human pancreases are quite similar. In both species, it is a retroperitoneal organ, and the pancreatic head wraps the portal vein [5]. In addition, the firmness of the pig pancreatic parenchyma is similar to the gland in humans [6]. Physiologically, pig islets offer a very competitive product for β-cell replacement because of their morphological characteristics, ability to respond to glucose challenge, and cell composition and also because of the fact that the pig and human insulin differ in only one amino acid [5, 7]. Among the new emerging technologies for diabetes therapy, gene and cellular injections are currently attractive and of great potential. However, there are persistent and severe obstacles to their applications mainly because of the topography and structure of the pancreas [3]. So far, there are no effective ways of approaching the pancreas without causing significant unwanted effects, such as infection of other organs [8] or toxicity and damage of the pancreas parenchyma [3, 9]. Arterial or venous injection
Sol-Gel Silica Matrix as Reservoir for Controlled Release of Paracetamol: Characterization and Kinetic Analysis  [PDF]
Tessy López, Mayra álvarez, Paola Ramírez, Gustavo Jardón, Miriam López, Guadalupe Rodriguez, Itzel Ortiz, Octavio Novaro
Journal of Encapsulation and Adsorption Sciences (JEAS) , 2016, DOI: 10.4236/jeas.2016.62005
Abstract: Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are usually suitable candidates for the development of drug delivery devices. Sol-gel chemistry represents an easy method to obtain porous silica nanoparticles. Mesoporous silica nanomaterials have been widely used for drug delivery purposes. In this work we synthesized silica based materials using two molar alkoxide:water ratios 1:4 and 1:8, incorporating paracetamol to develop a nano-sized matrix for controlled release purposes. The samples exhibited different values for surface area, porosity, particle size and distinct punctual defects. Infrared and UV-visible spectroscopic studies were carried out to demonstrate the effect of water concentration and the adequate incorporation of paracetamol molecules. Nitrogen adsorption characterization was realized and the estimated BET surface values were from 532 to 825 m2/g. Kinetic analysis of drug release profiles was performed using the hyperbola model. Transmission electron micrographs showed that all the materials formed aggregates of small particles with size between 10 - 60 nm. Mesoporous SiO2 materials were proved to be a suitable system for controlled release of paracetamol.
The Advantages of Using a Computer-Based Integrated Assessment to Promote Cooperative Behavior in Groundwater Management  [PDF]
Oliver López Corona, Pablo Padilla, Octavio Pérez Maqueo, Oscar Escolero
Advances in Applied Sociology (AASoci) , 2012, DOI: 10.4236/aasoci.2012.24044
Abstract:


The ultimate goal of environmental impact assessment is to guarantee that benefits generated by a development project will not cause highly negative effects on the environment or public health. The fulfillment of this goal depends on the willingness of proponents and society to cooperate. The information management, its accessibility to community and the educational level of participants are of great relevancy too. Cooperation is not always attainable due to conflicts between individual and community interests. Conflict leads to a variety of cooperative and non-cooperative responses, depending on the information available to the actors. In order to capture the tendency in which a community perceives the proposals, we introduced an information index. We prove that computer models have a direct impact on this information index. This computer-based approach, leads the EIA to the paradigm of adaptive environmental assessment and management. To implement this, a system based on artificial intelligence and game theory was used to resolve a study case of conflict in groundwater management.


IPv6 sobre ATM
Salcedo,Octavio; López,Danilo; Castellanos,Marina;
Tecnura , 2011,
Abstract: providing quality of service (qos) from communication networks in a global environment, is now one of the main fields of research, mainly due to the increasing importance of applications such as voip, video conferencing, stream video and atm. the main objective is to present and and audio, distance education, among others. discuss the main considerations and solutions this article is presented as a technology for pro-that exist in the integration of ip traffic in atm viding quality service, the integration of ipv6 technology.
Evaluación de los protocolos OSPF-TE y BGP en funciones de autodescubrimiento para L1VPN sobre GMPLS
Salcedo,Octavio; López,Danilo; Hernández,Cesar;
Tecnura , 2012,
Abstract: gmpls (generalized multiprotocol label switching architecture) is a new framework of protocols which is not only an extended version of mpls. instead of that it is a specialized group of protocols to discover neighbors, discover link state information, topology management, route management, load balancing, centralized control, bandwidth on demand management and management of vpns (virtual private networks) in physical-optical level through the use of adequate optical devices. in this paper are evaluated the results of a simulation for autodiscovery mechanism for a layer one vpn using the ospf-te and bgp protocols and comparing them. this paper pretends to give a vision to the reader of the potential of gmpls framework and analyze the advantages and disadvantages to use ospf-te instead bgp for autodiscovery purposes in a layer one virtual private network for an specific network scenario.
Brecha Digital por Estatus Socio-Económico en la Localidad de Ciudad Bolívar de Bogotá (Colombia)
Pedraza,Luis F; López,Danilo A; Salcedo,Octavio J;
Información tecnológica , 2012, DOI: 10.4067/S0718-07642012000600008
Abstract: in this paper the analysis of the impact of information and communication technology (ict) especially for the internet service in the area of ciudad bolivar in bogota-colombia, one of the sectors with the highest poverty rates in the city. the main objective of the study is to gather relevant information to identify the characteristics of the area in terms of technology and basic needs that can be supplied or improved through ict. to properly characterize the needs of the population, three kinds of surveys were done: household, environment and enterprise. then, the statistical results of this study are presented, taking into account the permissible error and the estimated confidence level.
Performance evaluation in MPLS/IP datanetworks
López,Danilo; Salcedo,Octavio; Hernández,César;
Revista Facultad de Ingeniería Universidad de Antioquia , 2009,
Abstract: this paper shows the results of a study on data transmission with different characterization (best-effort, high-priority best-effort and two types of real time traffic) through the switching protocol for multi-protocol labels in ip networks, compared to the ip data transmission using the asynchronous transfer mode. this study illustrates the best performance the mpls shows under a network congestion. the ns_2 discrete event simulator was used as experimentation tool.
Estudio comparativo de la utilización de ancho de banda con los protocolos SIP e IAX
Salcedo,Octavio; López,Danilo; Hernández,Cesar;
Tecnura , 2012,
Abstract: within the voip networks environment, there are three protocols that solve the problem of voice packet signaling, known as "highlight protocols": h323, sip and iax. particularly, this document focuses on a specific difference between sip and iax: the bandwidth usage, which is an essential parameter in order to design and optimize a voip network for an organization. one of the most important factors to consider when building voip networks is proper planning capacity. about planning capacity, bandwidth calculation is an important factor to consider when designing and troubleshooting packet voice networks for good voice quality. this paper presents important explanations about the bandwidth utilization over voip networks; this includes some theoretical foundations and bandwidth calculation on a perfow basis for a voip trunk, in which different voice codecs are enabled (specifically g.711 and gsm) together with voip protocols such as sip and iax. voice over ip (voip) is applied. these calculations are compared against the results obtained from traffic analyzers over a physical ethernet trunk between two asterisk servers into a specific lan, simulating two different branches of an organization. both the analysis of the results obtained and the conclusions from this work are useful when calculating the maximum number of simultaneous calls or the minimum capacity of a data link that is necessary for a particular number of voice conversations, taking into account the audio codecs used and the signaling and data fow protocols.
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