Role of surgical therapy in the treatment of refractory ascites

In 5-10% of cases ascites is not controlled by medical therapy and is defined refractory. These patients may be submitted to one of the four following surgical options: portal-systemic shunt, peritoneo-venous shunt, transjugular intrahepatic portal-systemic shunt, orthotopic liver transplantation. Although the portal-systemic shunt is efficient in clearing ascites, it does not improve the survival, which depends on liver function, and it is complicated by an important incidence of encephalopathy. Since the patients with refractory ascites and good hepatic risk are not usually many, it is possible to understand why derivative surgery has been disappointing with this indication. Although the peritoneo-venous shunt is associated with a significant rate of valve obstruction, it is an easy, effective and not expensive treatment. So, till now, it has been considered the first choice procedure of refractory ascites, if any situations, determinating the onset of postoperative complications, are not present. Recently a new method has been introduced in the therapy of portal hypertension, the transjugular intrahepatic portal-systemic shunt. This is a bloodless portal-systemic derivation and so it has caused great enthusiasm even if the available data are insufficient to give a definitive opinion on its role in management of ascites. Certainly the liver transplantation, which presents the great advantage to treat both the cirrhosis and its complications, seems to be the most rational therapy for these patients. However, at least for this moment, the well-known absence of organ donors makes still actual the palliative surgical measures.     

Antivasoconstrictor and antiaggregatory activities of picotamide unrelated to thromboxane A2 antagonism

Picotamide is a dual thromboxane (Tx) A2 receptor antagonist/Tx synthase inhibitor although some observations suggest an anti-vasoconstrictor effect independent of TxA2 inhibition/antagonism. The aim of our study was to assess whether picotamide antagonises vascular contractions induced by different vasoactive substances in vitro. Picotamide inhibited competitively the contraction of rabbit aortic rings induced by the TxA2 mimetic U46619 (pA2 = 3.59) but also the contractions induced by phenylephrine (pA2 = 3.93) and serotonin (5-HT) (pA2 = 5.81) although in a not competitive way. Picotamide did not inhibit potassium-induced contractions, thus excluding aspecific effects on vascular smooth muscle. Picotamide inhibited 5-HT-induced platelet aggregation in vitro with an IC50 (212 microM) similar to that found when other aggregating stimuli are used, but it did not affect shape change (IC50 > 1 mM) suggesting that the effects of picotamide can not be ascribed to 5-HT2-receptor antagonism; in the same experimental conditions neither a Tx-receptor antagonist (BM13.177) nor a dual Tx-receptor antagonist/synthase inhibitor (ridogrel) affected 5-HT-induced platelet responses. Our studies demonstrate that picotamide exerts antivasoconstrictor and platelet inhibitory effects unrelated to TxA2 antagonism. This activity may contribute to the anti-thrombotic/anti-ischaemic effects of the drug in vivo.     

Conservative approach to inflammatory nasofrontal duct disease

Endoscopic data reveal that mucosal disease frequently recurs following the surgical treatment of chronic diffuse hyperplastic frontal sinus and nasofrontal duct disease. However, this group of patients often remains asymptomatic. We present 40 patients who underwent endoscopic sinus surgery with a 4-year mean follow-up. Postoperative endoscopy revealed mucosal disease within the frontal recess in 39 of the 40 (97.5%) patients; however, only 3 of the 40 (7.5%) were symptomatic. Of these 3 patients, 1 underwent revision surgery. Historical information demonstrates the potential for significant nasofrontal duct stenosis associated with such revision surgery. On the basis of our initial results, endoscopic observation and medical therapy seem to be successful in controlling the symptoms associated with this disease process.     

Assessing refactorings for usability in e-commerce applications

Refactoring has been reported as a helpful technique to systematically improve non-functional attributes of software. This paper evaluates the relevance of refactoring for improving usability on web applications. We conducted an experiment with two replications at different locations, with subjects of different profiles. Objects chosen for the experiment were two e-commerce applications that exhibit common business processes in today’s web usage. Through the experiment we found that half of the studied refactorings cause a significant improvement in usability. The rest of the refactorings required a post-hoc analysis in which we considered aspects like user expertise in the interaction with web applications or type of application. We conclude that, when improving quality in use, the success of the refactoring process depends on several factors, including the type of software system, context and users. We have analyzed all these aspects, which developers must consider for a better decision support at the time of prioritizing improvements and outweighing effort.     

Peer-assisted content distribution on a budget

In this paper, we propose a general framework and present a prototype implementation of peer-assisted content delivery application. Our system – called Cyclops – dynamically adjusts the bandwidth consumed by content servers (which represents the bulk of content delivery costs) to feed a set of swarming clients, based on a feedback signal that gauges the real-time health of the swarm. Our extensive evaluation of Cyclops in a variety of settings – including controlled PlanetLab and live Internet experiments involving thousands of users – shows a significant reduction in content distribution costs when compared to existing swarming solutions, with a minor impact on the content delivery times.     

Fault tolerant control of uncertain dynamical systems using interval virtual actuators

In this paper, a model reference fault tolerant control strategy based on a reconfiguration of the reference model, with the addition of a virtual actuator block, is presented for uncertain systems affected by disturbances and sensor noise. In particular, this paper (1) extends the reference model approach to the use of interval state observers, by considering an error feedback controller, which uses the estimated bounds for the error between the real state and the reference state, and (2) extends the virtual actuator approach to the use of interval observers, which means that the virtual actuator is added to the control loop to preserve the nonnegativity of the interval estimation errors and the boundedness of the involved signals, in spite of the fault occurrence. In both cases, the conditions to assure the desired operation of the control loop are provided in terms of linear matrix inequalities. An illustrative example is used to show the main characteristics of the proposed approach.     

An approach and an Eclipse-based environment for enhancing the navigation structure of Web sites

This paper presents an approach based on information retrieval and clustering techniques for automatically enhancing the navigation structure of a Web site for improving navigability. The approach increments the set of navigation links provided in each page of the site with a semantic navigation map, i.e., a set of links enabling navigating from a given page to other pages of the site showing similar or related content. The approach uses Latent Semantic Indexing to compute a dissimilarity measure between the pages of the site and a graph-theoretic clustering algorithm to group pages showing similar or related content according to the calculated dissimilarity measure. AJAX code is finally used to extend each Web page with an associated semantic navigation map. The paper also presents a prototype of a tool developed to support the approach and the results from a case study conducted to assess the validity and feasibility of the proposal.     

Correlations between abnormalities on brain SPECT scan and interictal EEG-foci in children with 'intractable' partial epilepsy

SPECT scanning with Tc99mHM-PAO was performed on 40 children with 'intractable' partial epilepsy; 27 patients had abnormalities on SPECT images consisting of areas of decreased cerebral blood flow. In 18 of these 27 subjects there was a good correlation between site of the abnormalities on SPECT scan and interictal EEG foci. 12 patients with regionally decreased CBF had also neuroimaging (C.T. and/or R.M.I.) abnormalities. The brain SPECT provides more precise detection of epileptogenic foci, when used to complement EEG, also in childhood-onset epilepsy.     

Structure-based object representation and classification in mobile robotics through a Microsoft Kinect

A new approach enabling a mobile robot to recognize and classify furniture-like objects composed of assembled parts using a Microsoft Kinect is presented. Starting from considerations about the structure of furniture-like objects, i.e., objects which can play a role in the course of a mobile robot mission, the 3D point cloud returned by the Kinect is first segmented into a set of “almost convex” clusters. Objects are then represented by means of a graph expressing mutual relationships between such clusters. Off-line, snapshots of the same object taken from different positions are processed and merged, in order to produce multiple-view models that are used to populate a database. On-line, as soon as a new object is observed, a run-time window of subsequent snapshots is used to search for a correspondence in the database.Experiments validating the approach with a set of objects (i.e., chairs, tables, but also other robots) are reported and discussed in detail.     

Benchmarking parallel processing platforms: an applicationsperspective

Given the increased availability of general purpose parallel computers two issues arise: One needs to compare the performance of the different available platforms using realistic examples, and it is necessary to write application software that can be ported easily in order to take advantage of different platforms. The authors address these issues from an applications point of view. They are interested in the use of general purpose parallel computers for simulation tasks needed during the design of very large scale integrated (VLSI) circuits. They characterize the simulation task as a useful benchmark and introduce a high level process view of parallel simulation that is helpful for deriving portable parallel programs. Details of the partitioning strategy and the simulation algorithm used in the application are given. They discuss their implementation on different parallel machines and give statistics of various experiments