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Search Results: 1 - 10 of 481126 matches for " Raquel A Ferreira "
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Substrate texture properties induce triatomine probing on bitten warm surfaces
Raquel A Ferreira, Marcos H Pereira, Marcelo G Lorenzo
Parasites & Vectors , 2011, DOI: 10.1186/1756-3305-4-111
Abstract: The presence of a latex cover on a thermal source induced a change in the biting pattern shown by bugs. In fact, with latex covered sources it was possible to observe long bites that were never performed in response to warm metal surfaces. The total number of bites was higher in intact versus unilaterally antennectomized insects. These bites were significantly longer in intact than in unilaterally antennectomized insects.Our results suggest that substrate recognition by simultaneous input through thermal and mechanical modalities is required for triggering maxillary probing activity.Triatomine bugs are vectors of Chagas' disease [1-3], which is caused by the protozoan parasite Trypanosoma cruzi. This disease is one of the main public health problems in Latin America. Endemic to 21 countries, the disease affects approximately 15-16 million people, while another 75-90 million are exposed to risk of transmission [4]. In Venezuela, Colombia and some parts of Central America, Rhodnius prolixus St?l (1859) is the main vector of this parasite [5].Triatomine bugs rely on a number of sensory cues that are emitted by their hosts, mainly chemical and thermal, for orienting when they search for a blood-meal. The heat emitted by warm blooded animals is the main cue used by triatomine bugs to locate a host at short distances [6,7]. Indeed, it is the only stimulus that can trigger biting in these bugs [8-10]. A sequence of behavioural responses is shown by R. prolixus when confronted with a heat source [8]. Initially, this involves only antennal movements that are followed soon after by locomotor activity during which the antennae are rhythmically flexed up and down (8). Finally, insects extend their proboscis just before they touch the source with one or both antennae [8]. This process of distance estimation is presumably mediated by triangulation based on the integration of the information obtained by both antennae [6]. More recently, it was suggested that thermal gradients form
Histamine modulates microglia function
Raquel Ferreira, Tiago Santos, Joana Gon?alves, Gra?a Baltazar, Lino Ferreira, Fabienne Agasse, Liliana Bernardino
Journal of Neuroinflammation , 2012, DOI: 10.1186/1742-2094-9-90
Abstract: Firstly, we detected the expression of all known histamine receptor subtypes (H1R, H2R, H3R and H4R), using a murine microglial cell line and primary microglia cell cultures from rat cortex, by real-time PCR analysis, immunocytochemistry and Western blotting. Then, we evaluated the role of histamine in microglial cell motility by performing scratch wound assays. Results were further confirmed using murine cortex explants. Finally, interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) levels were evaluated by ELISA measurements to determine the role of histamine on the release of these inflammatory mediators.After 12 h of treatment, 100 μM histamine and 10 μg/ml histamine-loaded poly (lactic-co-glycolic acid) microparticles significantly stimulated microglia motility via H4R activation. In addition, migration involves α5β1 integrins, and p38 and Akt signaling pathways. Migration of microglial cells was also enhanced in the presence of lipopolysaccharide (LPS, 100 ng/ml), used as a positive control. Importantly, histamine inhibited LPS-stimulated migration via H4R activation. Histamine or H4R agonist also inhibited LPS-induced IL-1β release in both N9 microglia cell line and hippocampal organotypic slice cultures.To our knowledge, we are the first to show a dual role of histamine in the modulation of microglial inflammatory responses. Altogether, our data suggest that histamine per se triggers microglia motility, whereas histamine impedes LPS-induced microglia migration and IL-1β release. This last datum assigns a new putative anti-inflammatory role for histamine, acting via H4R to restrain exacerbated microglial responses under inflammatory challenge, which could have strong repercussions in the treatment of CNS disorders accompanied by microglia-derived inflammation.
Nós traumáticos, jogo e simboliza??o
Ferreira,Raquel;
Análise Psicológica , 1999,
Abstract: in this article, the author intends to reflect the problem of trauma from a psychoanalytic point of view. she also tries to apply this perspective in the community observation (in angola), in a post-war situation. finally, she provides a few clinic examples of the conceptual proposals.
O véu da mente
Ferreira,Raquel;
Análise Psicológica , 1999,
Abstract: the author deals briefly with some epistemological questions, trying to establish bonds between the relativity theory, quantum mechanics (considering that the first opens the way to the latter, in spite of einstein's strong opposition) and the psychoanalytic field, namely after bion. to illustrate this point of view, she presents a small clinical vignette of a patient who has bulimic suffering, and who is elaborating very painful experiments of separation from the primary object, and she examines a few transitions in the psychic structure.
Do Haematophagous Bugs Assess Skin Surface Temperature to Detect Blood Vessels?
Raquel A. Ferreira, Claudio R. Lazzari, Marcelo G. Lorenzo, Marcos H. Pereira
PLOS ONE , 2007, DOI: 10.1371/journal.pone.0000932
Abstract: Background It is known that some blood-sucking insects have the ability to reach vessels under the host skin with their mouthparts to feed blood from inside them. However, the process by which they locate these vessels remains largely unknown. Less than 5% of the skin is occupied by blood vessels and thus, it is not likely that insects rely on a “random search strategy”, since it would increase the probability of being killed by their hosts. Indeed, heterogeneities along the skin surface might offer exploitable information for guiding insect's bites. Methodology/Principal Findings We tested whether the bug Rhodnius prolixus can evaluate temperature discontinuities along the body surface in order to locate vessels before piercing the host skin. When placed over a rabbit ear, the bug's first bites were mostly directed towards the main vessels. When insects were confronted to artificial linear heat sources presenting a temperature gradient against the background, most bites were directly addressed to the warmer linear source, notwithstanding the temperature of both, the source and the background. Finally, tests performed using uni- and bilaterally antennectomized insects revealed that the bilateral integration of thermal inputs from both antennae is necessary for precisely directing bites. Conclusions/Significance R. prolixus may be able to exploit the temperature differences observed over the skin surface to locate blood vessles. Bugs bite the warmest targets regardless of the target/background temperatures, suggesting that they do not bite choosing a preferred temperature, but select temperature discontinuities along the skin. This strategy seems to be an efficient one for finding blood vessels within a wide temperature range, allowing finding them on different hosts, as well as on different areas of the host body. Our study also adds new insight about the use of antennal thermal inputs by blood sucking bugs.
Dose-dependent expression of neuronal injury markers during experimental osteoarthritis induced by monoiodoacetate in the rat
Joana Ferreira-Gomes, Sara Ad?es, Raquel Sousa, Marcelo Mendon?a, José Castro-Lopes
Molecular Pain , 2012, DOI: 10.1186/1744-8069-8-50
Abstract: OA animals showed the characteristic histopathological changes of the joints and the accompanying nociceptive behaviour, evaluated by the Knee-Bed and CatWalk tests. An increase of ATF-3 expression was detected in the DRG of OA animals as early as 3?days after the injection of 1 or 2?mg of MIA and 7?days after the injection of 0.3?mg. NPY expression was increased in animals injected with 1 or 2?mg of MIA, at day 3 or in all time-points, respectively. From day 7 onwards there was a massive increase of GAP-43 expression in ATF-3 cells.The expression of the neuronal injury markers ATF-3 and NPY as well as an up-regulation of GAP-43 expression, indicative of peripheral fibre regeneration, suggests that axonal injury and a regeneration response may be happening in this model of OA. This opens new perspectives in the unravelling of the physiopathology of the human disease.
Correla??o entre equilíbrio corporal e capacidade funcional de idosos com disfun??es vestibulares cr?nicas
Sousa, Raquel Ferreira de;Gazzola, Juliana Maria;Ganan?a, Maurício Malavasi;Paulino, Célia Aparecida;
Brazilian Journal of Otorhinolaryngology , 2011, DOI: 10.1590/S1808-86942011000600017
Abstract: vestibular disorders are common among the elderly, mainly resulting in dizziness and imbalance - symptoms which can impact daily routine activities. aim: to study the correlation between body balance and functional capacity and a comparison of risk of falls, actual falls and the functional capacity of the elderly with chronic vestibular dysfunctions. materials and methods: a cross-sectional, clinical and experimental study with 50 senior citizens - 60 to 86 years, with chronic peripheral vestibular dysfunction. these participants underwent body balance assessment by the dynamic gait index (dgi) and functional capacity assessment by the functional independence measure (fim). the data was tested using the spearman correlation and comparison tests, mann-whitney and kruskal- wallis, being α=5% (0.05). results: there was a significant correlation between the total dgi score and all fim scores, especially the total score (r=0.447; p<0.001) and loss of functional capacity in elderly patients with the highest risk of falling (p<0.001). conclusion: there is a positive correlation between body balance and functional capacity in elderly patients with peripheral vestibular disorders, that is: the better the balance, the better the individual's functional capacity. in addition, a worse functional capacity increases the individual's risk of falling.
Catálise assimétrica na ciclopropana??o de olefinas
Le?o, Raquel A. C.;Ferreira, Vítor F.;Pinheiro, Sergio;
Química Nova , 2007, DOI: 10.1590/S0100-40422007000700039
Abstract: the main methodologies in the asymmetric cyclopropanation of alkenes with emphasis on asymmetric catalysis are covered. exemples are the simmons-smith reaction, the use of diazoalkanes and reactions carried out by decomposition of a-diazoesters in the presence of transition metals.
Ades?o a protocolo pós-exposi??o ocupacional de acidentes entre cirurgi?es dentistas
Martins,Andréa Maria Eleutério de Barros Lima; Pereira,Rodrigo Dantas; Ferreira,Raquel Concei??o;
Revista de Saúde Pública , 2010, DOI: 10.1590/S0034-89102010005000018
Abstract: objective: to analyze the compliance with occupational post-exposure protocol for accidents and factors associated with compliance among dental surgeons. methods: a cross-sectional study was performed in the municipality of montes claros, southeastern brazil, from 2007 to 2008, with accident reports from needles and sharp instruments among practicing dental surgeons. variables describing the dentists' characteristics, work conditions, clients, injuries from needles and sharp instruments and post-accident actions were evaluated by means of a previously tested, structured questionnaire. the data underwent descriptive analysis and chi-square testing (p<0.05). results: a total of 241 dentists (89.2%) answered the questionnaire. compliance with occupational post-exposure protocol was reported by 51.5%. the majority of the professionals reported seeing blood at the time of the accident. burs were the instrument most often involved in accidents, and the finger was the most injured body part. compliance with a post-exposure protocol was more prevalent among those with greater monthly income (or=2.42; 95% ci=1.03;5.71), continuing education in the last two years (or=2.16; 95% ci=1.09;4.27) and who took regular breaks every four hours (or=1.23; 95% ci=1.23;4.92). dental surgeons who attended to children (or=0.50; 95%ci=0.27;0.93) and to individuals from the middle, middle-high and high socioeconomic classes (or=0.54, 95% ci=0.31;0.95) showed less compliance with the occupational post-exposure protocol. the frequency of compliance to a post-exposure protocol was significantly greater among individuals who followed the actions described in post-exposure protocols. conclusions: there is low compliance with occupational post-exposure protocols among dentists, which is influenced by the knowledge and monthly income of professionals, by taking regular breaks, by age group and the socioeconomic class of the clientele.
Anti-inflammatory and opioid-like activities in methanol extract of Mikania lindleyana, sucuriju
Frederico A. Vanderlinde,Fabio F. Rocha,David C. Malvar,Raquel T. Ferreira
Revista Brasileira de Farmacognosia , 2012,
Abstract: Mikania lindleyana DC., Asteraceae (sucuriju), grows in the Amazon region, where is frequently used to treat pain, inflammatory diseases and scarring. This study was carried out to investigate phytochemical profile accompanied by in vivo antinociceptive and anti-inflammatory screening of n-hexane (HE), dichloromethane (DME) and methanol (ME) extracts obtained from the aerial parts of the plant. The oral administration of ME (0.1, 0.3, 1 g/kg) caused a dose-related reduction (16.2, 42.1 e 70.2%) of acetic acid-induced abdominal writhing while HE and DME (1 g/kg, p.o.) were ineffective. In the hot plate test, ME (300 mg/kg, p.o.) increased the latency of heat stimulus between 30 and 120 min and inhibited the first (45%) and second (60%) phases of nociception in the formalin test. The antinociception induced by ME or positive control fentanyl (150 μg/kg, s.c.) in hot plate and formalin tests was prevented by naloxone (3 mg/kg, s.c.). When submitted to the carrageenan-induced peritonitis test, ME (0.5, 1.0, 2.0 g/kg, p.o.) impaired leukocyte migration into the peritoneal cavity by 46.8, 59.4 and 64.8% respectively, while positive control dexamethasone (2 mg/kg, s.c.), inhibited leukocyte migration by 71.1%. These results indicate that the antinociception obtained after oral administration of methanol extract of M. lindleyana involves anti-inflammatory mechanisms accompanied with opioid-like activity which could explain the use of the specie for pain and inflammatory diseases.
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