Response to prophylactic treatment of benign headache in children

INTRODUCTION: Common childhood headaches seldom require prophylactic treatment which, nevertheless, is quite often unsatisfactory. OBJECTIVE: To study drug and non-drug related factors that may influence the therapeutic response. MATERIAL AND METHODS: A four-month follow-up study of all patients attended during a year at the neuropediatric, outpatient hospital-based clinic, with > or = 2 monthly migraine without aura attacks, > or = 10 tension-type headaches, or both types of headaches. Patients were randomized to be treated on an open basis, placebo controlled, with flunarizine or piracetam. Headache frequency was evaluated according to treatment and patients' basal characteristics. RESULTS: 98 patients studied (56 migraine without aura, 24 tension-type headache, 18 mixed). 33% dropped out; they were school underachievers more frequently than those that completed the protocol. Of those completing the protocol and treated with placebo as the first choice of therapy, 27% reported total remission of symptomatology; those not remitting with placebo were high achievers at school significatively more frequently. At the end of the trial, 43% of the initially randomized patients still complained of headaches, regardless of treatment, showing a seasonal relationship. CONCLUSIONS: Prophylaxis of benign childhood headaches is needed in less than half of those reporting a high headache frequency; school achievement should be taken into consideration as another clue to compliance and headache persistence. On a short-term basis only the seasonal influence and the placebo effect can be held responsible for amelioration of symptomatology.     

Free radical enhancement promotes leucocyte recruitment through a PAF and LTB4 dependent mechanism

In the present investigation we studied the concerted role of superoxide anion, platelet activating factor (PAF) and leukotriene B4 (LTB4) in the mechanism that results in polymorphonuclear leucocyte accumulation induced by oxygen free radicals in rat pancreas. This was done by comparing the effects of a PAF antagonist (BN-52021), a LTB4 inhibitor (MK-886) and superoxide dismutase (SOD) in a experimental rat model of inflammation elicited by the oxygen free radicals induced via infusion of xanthine/xanthine oxidase. Also, the effect of independent LTB4 infusion has been studied. The results show that increases in polymorphonuclear cell infiltration (evaluated by tissue histology), myeloperoxidase and LTB4 levels induced in pancreas by infusion of xanthine/xanthine oxidase were abolished by the administration of either the PAF antagonist, the LTB4 inhibitor, or SOD. The fact that BN-52021 could prevent neutrophil recruitment and LTB4 synthesis suggests that PAF is a necessary step for subsequent LTB4 synthesis and polymorphonuclear leucocyte accumulation.     

An Infrastructure for Argumentative Agents

Multiagent systems are suitable for providing a framework that allows agents to perform collaborative processes in a social context. Furthermore, argumentation is a natural way of reaching agreements between several parties. However, it is difficult to find infrastructures of argumentation offering support for agent societies and their social context. Offering support for agent societies allows representation of more realistic environments to have argumentation dialogues. We propose an infrastructure to develop and execute argumentative agents in an open multiagent system. It offers tools to develop agents with argumentation capabilities. It also offers support for agent societies and their social context. The infrastructure is publicly available. Also, it has been implemented in an application scenario where argumentative agents try to reach an agreement about the best solution to solve a problem reported to the system.     

The formation of oxo- and hydroxy-fatty acids in heated fats and oils

A fast-food fat (mostly tallow), olive oil and safflower oil were heated in air for 4 d and periodically analyzed for oxofatty acids (OFA), monohydroxy-fatty acids (HFA) and polyhydroxy-fatty acids (PHFA). After transmethylation, the OFA were estimated as 2,4-dinitrophenylhydrazones, and the HFA and PHFA were quantitated as pyruvic acid 2,6-dinitrophenylhydrazone esters. At least half of the maximum concentration attained for OFA, HFA and PHFA was generated between 16–24 h of heating of each oil. Safflower oil contained greater concentrations of HFA and PHFA than either olive oil or the fast-food fat. The fastfood fat sample contained a greater concentration of OFA than did the other oils. The sum of the concentrations of OFA, HFA and PHFA at the time of maximum formation in the oils was approximately 260 μmoles/g at 48–72 h for safflower, 200 μmoles/g at 48–72 h for olive and 170 μmoles/g at 72 h for the fast-food fat. Presented at the 79th Annual AOCS Meeting, Phoenix, Arizona, May 8–12, 1988.     

Distribution of the free and oil‐trapped air bubbles in simulated broths containing fungal biomass

The location of air bubbles (i.e. inside oil drops or free in the aqueous phase) was studied by image analysis as a function of the oil and biomass concentrations in a 2 L stirred tank using a simulated fermentation medium (aqueoussalt solution, castor oil, air and fungal biomass) agitated by a Rushton turbine. The solid (fungal) phase plays an important role in defining the location of bubbles, as the percentage (in bubble volume) of bubbles trapped in oil increases threefold when biomass is added to the medium. The bubbles located inside oil drops were found to occupy 60% of the total bubble volume and to be 40% smaller than those which were non‐oil associated. This phenomenon has important implications for oxygen mass transfer in multiphase fermentations.     

A combined measure for quantifying and qualifying the topology preservation of growing self-organizing maps

The Self-Organizing Map (SOM) is a neural network model that performs an ordered projection of a high dimensional input space in a low-dimensional topological structure. The process in which such mapping is formed is defined by the SOM algorithm, which is a competitive, unsupervised and nonparametric method, since it does not make any assumption about the input data distribution. The feature maps provided by this algorithm have been successfully applied for vector quantization, clustering and high dimensional data visualization processes. However, the initialization of the network topology and the selection of the SOM training parameters are two difficult tasks caused by the unknown distribution of the input signals. A misconfiguration of these parameters can generate a feature map of low-quality, so it is necessary to have some measure of the degree of adaptation of the SOM network to the input data model. The topology preservation is the most common concept used to implement this measure. Several qualitative and quantitative methods have been proposed for measuring the degree of SOM topology preservation, particularly using Kohonen's model. In this work, two methods for measuring the topology preservation of the Growing Cell Structures (GCSs) model are proposed: the topographic function and the topology preserving map.     

Analysis of volatile composition of toasted and non‐toasted commercial chips by GC‐MS after an accelerated solvent extraction method

The analysis of the volatile profile of different oak chips carried out by gas chromatography–mass spectrometry after their isolation by accelerated solvent extraction permitted faster and thorough extractions, while the appearance of artefacts was avoided. Statistical analysis revealed that toasting treatment is the main factor for the volatile compounds with a great sensorial impact. Indeed, toasting process overrode the differences between species. Furthermore, it was evidenced that the toasting treatment is not a homogeneity process. Concentrations of furaneol, 2,3‐dihydro‐3,5‐dihydroxy‐6‐methyl‐4H‐pyran‐4‐one and 5‐hydroxymethylfurfural could be used to monitor the intensity of the toasting process. Differences in the volatile composition with respect to species were also found, being the most remarkable the high concentration of trans and cis‐β‐methyl‐γ‐octanolactone in oak chips from Quercus alba and Quercus petraea species. The differences found in the volatile composition of different commercial oak chips evidenced the necessity to know their chemical composition previously to predict their aromatic potential.     

Classification of Four Almond Cultivars Using Oil Degradation Parameters Based on FTIR and GC Data

Four almond cultivars (Marcona, Guara, Garrigues and Butte) have been classified using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and gas chromatography (GC) data. The data were obtained by completing the first stages of a thermal oxidative degradation process. The degradation process was monitored by using the variations in the main fatty acid methyl esters (FAME) content determined by GC and to changes in the infrared spectra recorded using the ATR-FTIR technique. In order to classify the almond cultivars, a stepwise linear discriminant analysis was applied to the data. The results indicated that, although the four almond oils evaluated here have a similar fatty acid composition, differences in linoleic acid content may be linked to oxidative stability. Butte cultivar samples had higher linoleic acid content and were more prone to oxidative deterioration.