Tobacco smoking and tooth loss in adults and elderly in Brazil: a populational-based cross-sectional study.

OBJECTIVES: To determine the association between smoking and tooth loss in individuals aged 18 years or more living in Brazil. METHODS: Secondary analysis of the 2019 Brazilian National Health Survey data. The outcome was self-reported tooth loss, and the main independent variable was tobacco smoking. Family income, schooling, sex and age were covariates. Multiple linear regression analysis determined the association between tobacco smoking and the number of missing teeth and then the average number of missing teeth was predicted according to smoking status. RESULTS: The mean number of missing teeth in 88,531 individuals aged 18 or more was 7.7 (95%CI: 7.6-7.8). At least one missing tooth was identified in 72.0% (95%CI: 71.4-72.6) of the population, 21.3% (95%CI: 20.9-21.7) had a non-functional dentition, 14.2% (95%CI: 13.9-14.6) had severe tooth loss and 10.3% (95%CI: 10.0-10.6) were edentulous. The adjusted regression coefficients for number of missing teeth showed that current or former smokers, individuals with low family income and schooling, older age and females exhibited higher tooth loss. Current and former smokers had 1.40 (95%CI: 1.35-1.46) and 1.13 (95%CI: 0.54-0.98) times more lost teeth than never smokers, respectively. CONCLUSIONS: Both tooth loss and smoking are common in Brazilians and are associated. Unfavorable socioeconomic status and demographic factors also predict tooth loss.

Incorporation of Cró thermal water in a dermocosmetic formulation: cytotoxicity effects, characterization and stability studies and efficacy evaluation.

OBJECTIVE: Development of cosmetic formulations to provide a controlled release of hydrophilic active compounds from mineral medicinal waters constitutes an attractive challenge. The objective of this study was the development and the characterization of a dermocosmetic gel formulation with Cró thermal water, from Beira Interior of Portugal, as a major functional ingredient. METHODS: Concentrations of mineral chemical elements of Cró thermal water were previously determined by inductively coupled plasma-optical emission spectrometry or mass spectrometry and cytotoxicity assays using thermal water were carried out on normal human dermal fibroblasts (NHDF) cells. Then, the Cró thermal water was included (more than 90%) in a developed gel formulation that was characterized through rheological and texture analysis and submitted to stability assays during 30 days. The effects on the skin volunteers, namely skin pH, the degree of hydration, transepidermal water loss and skin relief, were evaluated through non-invasive biometric techniques. A gel formulation including purified water was used as a control. RESULTS: Cró thermal water is rich on several chemical elements in particular sodium, silica, potassium and calcium besides some trace elements, with important functions for the skin. NHDF cells adhered and proliferated in the presence of thermal water confirming the biocompatibility of the major component of the gel formulation. The developed gel formulation based on thermal water resulted in an improvement of textural parameters, comparing with the purified water-based one. Significant improvements in the cutaneous biometric parameters (degree of hydration, transepidermal water loss and skin relief) of volunteers were also registered for the gel formulation containing thermal water. CONCLUSION: This study demonstrated for the first time the potential benefits of Cró thermal water in a gel formulation to be used in cosmetic and dermatological applications.

OBJECTIF: Le développement de formulations cosmétiques permettant une libération contrôlée des substances actives hydrophiles à partir d'eaux médicinales minérales constitue un défi attractif. L'objectif de cette étude était le développement et la caractérisation d'une formulation de gel dermocosmétique avec l'eau thermale de Cró, de Beira Interior au Portugal, comme ingrédient fonctionnel majeur. MÉTHODES: Les concentrations en éléments chimiques minéraux de l'eau thermale de Cró ont étés préalablement déterminées par spectrométrie d'émission optique avec plasma couplé par induction ou spectrométrie de masse et des essais de cytotoxicité utilisant de l'eau thermale ont été réalisés sur des cellules de fibroblastes dermiques humains normaux (NHDF). Ensuite, l'eau thermale de Cró a été incluse (plus de 90%) dans une formulation de gel développée qui a été caractérisée par analyse rhéologique et texture et soumise à des tests de stabilité pendant 30 jours. Les effets sur la la peau des volontaires, à savoir le pH de la peau, le degré d'hydratation, la perte d'eau transépidermique et le relief cutané, ont été évalués à l'aide de techniques biométriques non invasives. Une formulation de gel comprenant de l'eau purifiée a été utilisée comme témoin. RÉSULTATS: L'eau thermale de Cró est riche en plusieurs éléments chimiques, en particulier le sodium, la silice, le potassium et le calcium, en plus de certains oligo-éléments, avec des fonctions importantes pour la peau. Les cellules NHDF ont adhéré et ont proliféré en présence d'eau thermale, confirmant la biocompatibilité du composant principal de la formulation du gel. La formulation de gel développée à base d'eau thermale a permis une amélioration des paramètres de texture comparée à celle à base d'eau purifiée. Des améliorations significatives des paramètres biométriques cutanés (degré d'hydratation, perte en eau transépidermique et relief cutané) des volontaires ont également été enregistrées avec la formulation en gel contenant de l'eau thermale. CONCLUSION: Cette étude a démontré pour la première fois les avantages potentiels de l'eau thermale de Cró dans une formulation de gel destinée aux applications cosmétiques et dermatologiques.

Nutritional evaluation and productivity of supplemented sheep grazing in semiarid rangeland of northeastern Brazil.

Sheep production systems in Brazilian caatinga rangelands require supplementation adapted to changes in floristic and chemical composition as dry seasons progress. Meeting sheep nutritional needs in extensive semiarid systems is challenging because of sheep dietary preferences and habits. The objective of this trial was to evaluate the substitutive effect of concentrate supplementation on grazing sheep in the Brazilian caatinga rangeland and its consequences on performance in different seasons. The trial was conducted from March to August 2013 at Embrapa Goat and Sheep in Sobral, Ceará State, Brazil. Thirty-two Brazilian Somali multiparous ewes were submitted to estrus synchronization and controlled breeding. At the start of the trial, ewes averaged 30.45 + 2.60 kg body weight (BW). Ewes were divided into four groups and individually offered 0, 200, 350, or 500 g supplement head-1 day-1. Intake prediction and digestibility trials were evaluated at three periods: rainy season (April), transition rainy-dry (June), and dry season (August). Sheep weights were taken every 14 days to measure their performance from late gestation until weaning. Ewe BW and body condition score changes were determined too. Lamb BW changes were also measured every 14 days from birth through weaning. A completely randomized design with split plot arrangement using eight replications was used for intake and digestibility measurements. The differences between supplement offered (0, 200, 350, and 500 g sheep-1) and season (rainy, transition rainy-dry, and dry) were submitted to analyses of variance and multiple means were separated, where differences were detected, using the Tukey's test. During lactation up through weaning, ewes supplemented at 500 g day-1 had greater BW than ewes without supplement. Ewes supplemented with 200 g concentrate head-1 day-1 had 9.1% greater (P ≤ 0.05) BW at weaning and their lambs had 19.7% greater birth and 16.6% heavier wean BW despite lower dry matter intake compared to unsupplemented animals. Supplementation with 200 g concentrate increased carrying capacity by 28.8% during the dry season and by 20.5% during the rainy season. This study confirmed that in the dry season, when quality of rangeland forages decreases, supplementation contributes to greater DMI, improves postpartum and lactation BW recovery of ewes, and contributes to greater lamb birth and wean weights. Moreover, supplementation leads to feed substitution effects that may increase rangeland resilience by mitigating overgrazing. Supplementation with 200 g concentrate can also prevent negative energy balance for grazing animals, improving longer postnatal recovery, longer intervals between parturitions, fewer double and is necessary to ensure a better BW at birth to lambs.

Physicochemical fingerprinting of thermal waters of Beira Interior region of Portugal.

Mineral natural waters and spas have been used for therapeutic purposes for centuries, with Portugal being a very rich country in thermal waters and spas that are mainly distributed by northern and central regions where Beira Interior region is located. The use of thermal waters for therapeutic purposes has always been aroused a continuous interest, being dependent on physicochemical fingerprinting of this type of waters the indication for a treatment in a specific pathological condition. In the present work, besides a literature review about the physicochemical composition of the thermal waters of the Beira Interior region and its therapeutic indications, it was carried out an exhaustive multivariate analysis-principal component analysis and cluster analysis-to assess the correlation between different physicochemical parameters and the therapeutic indications claims described for these spas and thermal waters. These statistical methods used for data analysis enables classification of thermal waters compositions into different groups, regarding to the different variable selected, making possible an interpretation of variables affecting water compositions. Actually, Monfortinho and Longroiva are clearly quite different of the others, and Cró and Fonte Santa de Almeida appear together in all analysis, suggesting a strong resemblance between these waters. Thereafter, the results obtained allow us to demonstrate the role of major components of the studied thermal waters on a particular therapeutic purpose/indication and hence based on compositional and physicochemical properties partially explain their therapeutic qualities and beneficial effects on human health. This classification agreed with the results obtained for the therapeutic indications approved by the Portuguese National Health Authority and proved to be a valuable tool for the regional typology of mineral medicinal waters, constituting an important guide of the therapeutic armamentarium for well and specific-oriented pathological disturbs.

Comparative analysis of the pathological events involved in immune and non-immune TRALI models.

BACKGROUND AND OBJECTIVES: Transfusion-related acute lung injury (TRALI) is characterized by leukocyte transmigration and alveolar capillary leakage shortly after transfusion. TRALI pathogenesis has not been fully elucidated. In some cases, the infusion of alloantibodies (immune model), whereas in others the combination of neutrophil priming by proinflammatory molecules with the subsequent infusion of biological response modifiers (BRMs) in the hemocomponent (non-immune model) have been implicated. Our aim was to compare the pathological events involved in TRALI induced by antibodies or BRMs using murine models. MATERIALS AND METHODS: In the immune model, human HNA-2(+) neutrophils were incubated in vitro with a monoclonal antibody (anti-CD177, clone 7D8) directed against the HNA-2 antigen and injected i.v. in NOD/SCID mice. In the non-immune model, BALB/c mice were treated with low doses of lipopolysaccharide (LPS) followed by platelet-activating factor (PAF) infusion 2 h later. Forty minutes after PAF administration, or 6 h after neutrophil injection, lungs were isolated and histological analysis, determination of a variety of cytokines and chemokines including keratinocyte-derived chemokine (KC), MIP-2, the interleukins IL-1ß, IL-6, IL-8 as well as TNFα, cell influx and alveolar capillary leakage were performed. RESULTS: In both models, characteristic histological findings of TRALI and an increase in KC and MIP-2 levels were detected. In contrast to the immune model, in the non-immune model, there was a dramatic increase in IL-1ß and TNFα. However, capillary leakage was only detected if PAF was administrated. CONCLUSIONS: Regardless of the triggering event(s), KC, MIP-2 and integrins participate in TRALI pathogenesis, whereas PAF is essential for capillary leakage when two events are involved.

Cashew nut meal as feed supplement for lambs.

Cashew nut meal (CNM) is widely used in tropical countries due to the high protein and energy levels; therefore, it has potential to be an alternative feed supplementation for livestock. Our objective was to evaluate the use of CNM as feed supplement for lambs. Twenty-four lambs were divided into a randomized block design with four treatments, starting with a diet control of Tifton 85 (Cynodon spp.) hay and CNM as a supplement at three different levels representing 6, 12, and 18% of the total mixed ration (TMR) provided. There were evaluated intake (g/day and g/kgBW0.75); the digestibility of DM and nutrients; nitrogen balance; and ingestive behavior. The CP and ether extract (EE) intake (g/day) as well as DM, and organic matter (OM) intake (g/kgBW0.75) were influenced by supplementation with CNM in a positive linear increase (P < 0.05). The digestibility of DM, OM and NDF increased according to the levels of CNM up to 12% and markedly decreased at the higher level (P < 0.05). The EE and CP digestibility raised according to the CNM levels (P < 0.05) and consequently increased the nitrogen retention resulting in a positive nitrogen balance. The protein and energetic characteristics of CNM show that it can be used as an alternative supplementation to low-quality forages for lambs. However, its use as a single supplement ingredient above 7% on total mixed ration may reduce fiber digestibility.

Characterization of novel human intragenic antimicrobial peptides, incorporation and release studies from ureasil-polyether hybrid matrix.

Intragenic antimicrobial peptides (IAPs) are internal sequences of proteins with physicochemical similarities to Antimicrobial Peptides (AMPs) that, once identified and synthesized as individual entities, present antimicrobial activity. Many mature proteins encoded by the genomes of virtually any organism may be regarded as inner reservoirs of IAPs, conferring them ample biotechnological potential. However, IAPs may also share shortcomings with AMPs, such as low half-life in biological media and non-specific adsorption in eukaryotic cells. The present manuscript reports a translational approach that encompasses the uncovering of two novel IAPs from human proteins as well as the first results concerning the incorporation and sustained release of one of these peptides from ureasil-polyether hybrid polymeric films. For such, the software Kamal was used to scan putative IAPs in the human proteome, and two peptides, named Hs05 and Hs06, were identified, synthesized, and tested as antimicrobials. Biophysical assays were conducted using model phospholipid vesicles and 1H NMR solution structures in phospholipid micelles were obtained for the IAP Hs05. This peptide was incorporated in a polymeric matrix composed of the ureasil/PPO-PEO-PPO triblock copolymer, and the resulting films were evaluated by atomic force microscopy and imaging mass spectrometry. The release rate of Hs05 from the polymeric matrix was assessed and the antimicrobial activity of Hs05-loaded hybrid polymeric films was evaluated against the bacterium Escherichia coli. This study represents the first steps towards the development of polymeric films enriched with IAPs obtained from the human proteome as sustained release devices for topical application.

Rapid and long-lasting antidepressant-like effects of ketamine and their relationship with the expression of brain enzymes, BDNF, and astrocytes.

Ketamine (KET) is an N-methyl-D-aspartate (NMDA) antagonist with rapid and long-lasting antidepressant effects, but how the drug shows its sustained effects is still a matter of controversy. The objectives were to evaluate the mechanisms for KET rapid (30 min) and long-lasting (15 and 30 days after) antidepressant effects in mice. A single dose of KET (2, 5, or 10 mg/kg, po) was administered to male Swiss mice and the forced swim test (FST) was performed 30 min, 15, or 30 days later. Imipramine (IMI, 30 mg/kg, ip), a tricyclic antidepressant drug, was used as reference. The mice were euthanized, separated into two time-point groups (D1, first day after KET injection; D30, 30 days later), and brain sections were processed for glycogen synthase kinase-3 (GSK-3), histone deacetylase (HDAC), brain-derived neurotrophic factor (BDNF), and glial fibrillary acidic protein (GFAP) immunohistochemical assays. KET (5 and 10 mg/kg) presented rapid and long-lasting antidepressant-like effects. As expected, the immunoreactivities for brain GSK-3 and HDAC decreased compared to control groups in all areas (striatum, DG, CA1, CA3, and mainly pre-frontal cortex, PFC) after KET injection. Increases in BDNF immunostaining were demonstrated in the PFC, DG, CA1, and CA3 areas at D1 and D30 time-points. GFAP immunoreactivity was also increased in the PFC and striatum at both time-points. In conclusion, KET changed brain BDNF and GFAP expressions 30 days after a single administration. Although neuroplasticity could be involved in the observed effects of KET, more studies are needed to explain the mechanisms for the drug's sustained antidepressant-like effects.

Hypoglicemic effect of Leandra lacunosa in normal and alloxan-induced diabetic rats.

Leandra lacunosa, popularly known as "erva-do-jabuti", is used in Brazilian folkloric medicine for the treatment of diabetes mellitus. Based on this traditional indication, the aim of this work was to evaluate the hypoglycemic activity of the hydroalcoholic extract of L. lacunosa aerial parts (LLH) in normal and alloxan-induced diabetic rats. Chromatographic fractionation of LLH was also carried out by several techniques, affording isolation of the following major compounds: ursolic acid (1), kaempferol (2), luteolin (3), and quercetin (4). The oral administration of LLH (500 mg/kg) in normal rats caused a significant reduction of 24.7% (P<0.05) in the blood glucose levels after 2 h of treatment, while the administration of chlorpropamide (20 mg/kg, p.o.) led to a reduction of 40.2% (P<0.01). After oral administration of glucose (10 g/kg, p.o.), LLH (500 mg/kg, p.o.) significantly inhibited the increase in blood glucose levels compared with the negative control group. The oral treatment with LLH (500 mg/kg) in alloxan-induced diabetic rats significantly reduced the blood glucose levels in 47.8% after 4 h of treatment, while chlorpropamide resulted in a significant reduction of 71.7% in the 4th hour. Our results showed that LLH, displays hypoglycemic activity, which may be related to the effect of the major compounds identified in the crude extract. This study seems to provide biological evidence for the folkloric use of L. lacunosa in the treatment of diabetes mellitus.

[Infantile hepatic hemangioendothelioma. A multifocal, bilobular and asymptomatic case with spontaneous regression]. / Hemangioendotelioma hepático infantil. Un caso multifocal y bilobular, asintomático, con regresión espontánea.

Infantile hepatic hemangioendothelioma is a severe disease with a high mortality rate. Nevertheless these vascular lesions may experience spontaneous regression within 12 to 18 months. The decision of trying a specific treatment and the choice among the several therapeutic options remains controversial, particularly in those asymptomatic cases of multifocal, bilobular involvement. We describe a case of multifocal, bilobular and asymptomatic infantile hepatic hemangioendothelioma, untreated, and with spontaneous regression before 2 years of age.

Determination of antipsychotic drugs in hospital and wastewater treatment plant samples by gas chromatography/tandem mass spectrometry.

The development and performance evaluation of a method for the simultaneous determination of six antipsychotic drugs in hospital effluents and wastewater treatment plants (WWTP) samples are herein presented. The method involves an off-line mixed mode (reversed-phase and strong cation exchange) solid phase extraction (SPE) with gas chromatography (GC) coupled to tandem mass spectrometry (MS/MS). The present methodology was validated following internationally accepted criteria, and the studied parameters included selectivity, linearity, limits of detection (LOD) and quantitation (LLOQ), instrumental limits, precision and accuracy, stability and recovery. The procedure was linear for concentrations ranging from 0.1 to 10µg/L (0.02 to 2µg/L for haloperidol), with determination coefficients higher than 0.99 for all analytes. Intra- and inter-day precision was lower than 15% for all analytes at the studied concentrations, while accuracy remained between a ±15% interval. Recoveries ranged from 31% to 83%. Low LODs were achieved, between 2 and 10ng/L, allowing a reliable identification of all analytes at trace levels, using only 50mL as sample volume. All studied parameters complied with the defined criteria and the method was successfully applied to gather preliminary results of the determination of antipsychotics on hospital effluents and on influent and effluent of WWTPs, opening perspectives for the study of their fate in the aquatic environment.

Multiresistance and virulence factors of Staphylococcus aureus isolated from pigs / [Multirresistência e fatores de virulência de Staphylococcus aureus isolados de suínos]

The emergence of livestock-associated methicillin-resistant Staphylococcus aureus strains (LA-MRSA) and the potential role of pigs in the evolution of these strains has led to increased interest in research of these microorganisms. However, this has contributed to a lack of research in the isolation and characterization of methicillin-susceptible S. aureus strains (MSSA). In this study, the prevalence of S. aureus in pigs in the nursery and finishing stages were analyzed. The susceptibility profiles to antibiotics, tolerance to heavy metals, and biofilm production of the isolates were evaluated using phenotypic and genotypic techniques. A total of 1,250 colonies suggestive of Staphylococcus spp. were isolated from 128 pigs, of which 63.6% (n = 795) belonged to this microbial genus. Sixty-seven colonies isolated from 34 animals (26.5%) were confirmed as S. aureus (8.4%). No strains resistant to copper, zinc, or methicillin were detected; however, all strains presented a resistance profile to at least three different classes of antimicrobials and 21 produced biofilms. These data are of concern, as they indicate the need for increased surveillance in the use of antimicrobials as well as reinforce the importance of studies on MSSA strains.(AU)

A emergência de cepas de Staphylococcus aureus resistentes à meticilina associadas à pecuária (LA-MRSA) e o papel potencial dos suínos na evolução dessas cepas têm levado ao aumento do interesse na pesquisa desses microrganismos. No entanto, isso tem contribuído para a falta de estudos sobre o isolamento e a caracterização de cepas de S. aureus sensíveis à meticilina (MSSA). Neste estudo, foi analisada a prevalência de S. aureus em suínos nas fases de creche e terminação. Os perfis de suscetibilidade aos antibióticos, a tolerância a metais pesados e a produção de biofilme dos isolados foram avaliados por meio de técnicas fenotípicas e genotípicas. Um total de 1.250 colônias sugestivas de Staphylococcus spp. foi isolado de 128 suínos, das quais 63,6% (n = 795) pertenciam a esse gênero microbiano. Sessenta e sete colônias isoladas de 34 animais (26,5%) foram confirmadas como S. aureus (8,4%). Nenhuma cepa resistente ao cobre, ao zinco ou à meticilina foi detectada; entretanto, todas as cepas apresentaram perfil de resistência a pelo menos três classes diferentes de antimicrobianos e 21 produziam biofilme. Esses dados são preocupantes, pois indicam a necessidade de maior vigilância no uso de antimicrobianos, bem como reforçam a importância de estudos com cepas de MSSA.(AU)

Rapid and long-lasting antidepressant-like effects of ketamine and their relationship with the expression of brain enzymes, BDNF, and astrocytes

Ketamine (KET) is an N-methyl-D-aspartate (NMDA) antagonist with rapid and long-lasting antidepressant effects, but how the drug shows its sustained effects is still a matter of controversy. The objectives were to evaluate the mechanisms for KET rapid (30 min) and long-lasting (15 and 30 days after) antidepressant effects in mice. A single dose of KET (2, 5, or 10 mg/kg, po) was administered to male Swiss mice and the forced swim test (FST) was performed 30 min, 15, or 30 days later. Imipramine (IMI, 30 mg/kg, ip), a tricyclic antidepressant drug, was used as reference. The mice were euthanized, separated into two time-point groups (D1, first day after KET injection; D30, 30 days later), and brain sections were processed for glycogen synthase kinase-3 (GSK-3), histone deacetylase (HDAC), brain-derived neurotrophic factor (BDNF), and glial fibrillary acidic protein (GFAP) immunohistochemical assays. KET (5 and 10 mg/kg) presented rapid and long-lasting antidepressant-like effects. As expected, the immunoreactivities for brain GSK-3 and HDAC decreased compared to control groups in all areas (striatum, DG, CA1, CA3, and mainly pre-frontal cortex, PFC) after KET injection. Increases in BDNF immunostaining were demonstrated in the PFC, DG, CA1, and CA3 areas at D1 and D30 time-points. GFAP immunoreactivity was also increased in the PFC and striatum at both time-points. In conclusion, KET changed brain BDNF and GFAP expressions 30 days after a single administration. Although neuroplasticity could be involved in the observed effects of KET, more studies are needed to explain the mechanisms for the drug's sustained antidepressant-like effects.

nor-Lignans from the leaves of Styrax ferrugineus (Styracaceae) with antibacterial and antifungal activity.

Chemical examination of the leaves of Styrax ferrugineus yielded 5-[3''-(beta-D-glucopyranosyloxy)propyl]-7-methoxy-2-(3',4'-dimethoxyphenyl) benzofuran, along with the known nor-lignans 5-(3''-hydroxypropyl)-7-methoxy-2-(3',4'-methylenedioxyphenyl) benzofuran, 5-(3''-hydroxypropyl)-7-methoxy-2-(3',4'-dimethoxyphenyl)benzofuran, 5-[3''-(beta-D-glucopyranosyloxy)propyl]-7-methoxy-2-(3',4'-methylenedioxyphenyl)benzofuran and the lignan, dihydrodehydrodiconiferyl alcohol. All arylpropanoids isolated showed antibacterial and antifungal activities. The structures of the isolates were established by spectroscopic analysis.

Biosynthesis of friedelane and quinonemethide triterpenoids is compartmentalized in Maytenus aquifolium and Salacia campestris.

Maytenus aquifolium (Celastraceae) and Salacia campestris (Hippocrateaceae) species accumulate friedelane and quinonemethide triterpenoids in their leaves and root bark, respectively. Enzymatic extracts obtained from leaves displayed cyclase activity with conversion of the substrate oxidosqualene to the triterpenes, 3beta-friedelanol and friedelin. In addition, administration of (+/-)5-(3)H mevalonolactone in leaves of M. aquifolium seedlings produced radio labelled friedelin in the leaves, twigs and stems, while the root bark accumulated labelled maytenin and pristimerin. These experiments indicated that the triterpenes once biosynthesized in the leaves are translocated to the root bark and further transformed to the antitumoral quinonemethide triterpenoids.

Context in temporal sequence processing: a self-organizing approach and its application to robotics.

A self-organizing neural net for learning and recall of complex temporal sequences is developed and applied to robot trajectory planning. We consider trajectories with both repeated and shared states. Both cases give rise to ambiguities during reproduction of stored trajectories which are resolved via temporal context information. Feedforward weights encode spatial features of the input trajectories, while the temporal order is learned by lateral weights through delayed Hebbian learning. After training, the net model operates in an anticipative fashion by always recalling the successor of the current input state. Redundancy in sequence representation improves noise and fault robustness. The net uses memory resources efficiently by reusing neurons that have previously stored repeated/shared states. Simulations have been carried out to evaluate the performance of the network in terms of trajectory reproduction, convergence time and memory usage, tolerance to fault and noise, and sensitivity to trajectory sampling rate. The results show that the model is fast, accurate, and robust. Its performance is discussed in comparison with other neural-networks models.

Identification and control of dynamical systems using the self-organizing map.

In this paper, we introduce a general modeling technique, called vector-quantized temporal associative memory (VQTAM), which uses Kohonen's self-organizing map (SOM) as an alternative to multilayer perceptron (MLP) and radial basis function (RBF) neural models for dynamical system identification and control. We demonstrate that the estimation errors decrease as the SOM training proceeds, allowing the VQTAM scheme to be understood as a self-supervised gradient-based error reduction method. The performance of the proposed approach is evaluated on a variety of complex tasks, namely: i) time series prediction; ii) identification of SISO/MIMO systems; and iii) nonlinear predictive control. For all tasks, the simulation results produced by the SOM are as accurate as those produced by the MLP network, and better than those produced by the RBF network. The SOM has also shown to be less sensitive to weight initialization than MLP networks. We conclude the paper by discussing the main properties of the VQTAM and their relationships to other well established methods for dynamical system identification. We also suggest directions for further work.

[The use of acetylsalicylic acid as a platelet antiaggregant]. / Uso do acido acetil salicílico como antiagregante plaquetário.

PURPOSE: To comprove the efficiency of acetyl salicylic acid (ASA) as platelet antiaggregant drug, a 100 mg/day dose base. METHODS: Two hundred and fifty-eight patients were studied between 1988 and 1990. Platelet functions were measured using an aggregometer plus ADP 5 as platelet aggregation inductor. RESULTS: Two groups were studied: 1st group, using ASA (111 patients), 91 hypoaggregants; 2nd group, not using ASA (147 patients), 120 normals, 12 hypoaggregants and 15 hyperaggregants. From the 2nd group, 91 had another evaluation under the use of ASA and showed a clear effect of the drug. CONCLUSION: The use of aspirin, 100 mg/day dose, is enough to reduce platelet antiaggregation.

[Parvovirus B19 infection]. / A infecção pelo parvovirus B19.

In 1975, during blood screening for hepatitis B, Cossart et al. discovered the human parvovirus B19 (B19). It is a small, single strand DNA virus of the Parvoviridae family. This virus is widespread with 40-80% of adults showing evidence of infection. It is found in the respiratory secretions of viraemic patients and direct contact has been suggested as the most likely mode of transmission. Parenteral transmission is common during treatment with clotting-factor concentrates, but rarely occurs during transfusion with single donor products. Although B19 usually causes a self-limited illness, complications of infection can be severe and at times life threatening. In pregnant women, infection can lead to spontaneous abortions and hydrops fetalis and, in patients with haemolytic anaemias or in immunocompromised individuals, can induce aplastic crisis and chronic anaemias. The diagnosis can be made by indirect (testing for B19 antibodies) or direct methods (detecting B19 viremia). There are no vaccines or specific therapy currently available. Contact isolation is recommended for hospitalized patients.