Papers by Ricardo V Breda
Asia Pacific Allergy, Oct 1, 2019
Journal of Cellular Physiology, Jul 22, 2019
Journal of Cellular Physiology, Jun 10, 2019
Journal of Cellular Physiology, Feb 9, 2017
PARTICIPAÇÃO DAS ESPÉCIES REATIVAS DE OXIGÊNIO NA FORMAÇÃO DE REDES EXTRACELULARES DE EOSINÓFILOS... more PARTICIPAÇÃO DAS ESPÉCIES REATIVAS DE OXIGÊNIO NA FORMAÇÃO DE REDES EXTRACELULARES DE EOSINÓFILOS EM UM MODELO EXPERIMENTAL DE ASMA Josiane Silva Silveira, Géssica Luana Antunes, Eduardo Peil Marques, Fernanda Ferreira, Daniela Benvenutti Kaiber, Ricardo Vaz Breda, Carolina Luft, Mariana Severo, Angela Terezinha Wyse, Paulo Márcio Pitrez, Aline Andrea da Cunha Centro infant, Laboratório de Respirologia Pediátrica, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre-RS, Brasil. Departamento de Bioquímica, Laboratório de Neuroproteção e Doenças Metabólicas, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre-RS, Brasil. Instituto do Cérebro (INSCER), Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre-RS, Brasil.
Experimental Lung Research, 2021
Abstract Purpose Eosinophils are one of the main cells responsible to the inflammatory response i... more Abstract Purpose Eosinophils are one of the main cells responsible to the inflammatory response in asthma by the release of inflammatory molecules such as cytokines, reactive oxygen species (ROS), cytotoxic granule, eosinophil extracellular trap (EET), and lipid mediators as cysteinyl leukotriene (cysLT). The interconnections between these molecules are not fully understood. Here, we attempted to investigate the cysLT participation in the mechanisms of EET formation in an asthma model of OVA challenge. Materials and methods Before intranasal challenge with OVA, BALB/cJ mice were treated with a 5-lipoxygenase-activating protein (FLAP) inhibitor (MK-886), or with a cysLT1 receptor antagonist (MK-571) and the lung and bronchoalveolar lavage fluid (BALF) were analyzed. Results We showed that OVA-challenged mice treated with MK-886 or MK-571 had a decrease in inflammatory cells, goblet cells hyperplasia, and eosinophil peroxidase (EPO) activity in the airway. However, only OVA-challenged mice treated with MK-571 had an improvement in lung function. Also, treatments with MK-886 or MK-571 decreased Th2 cytokines levels in the airway. Moreover, we observed that OVA-challenged mice treated with MK-886 or MK-571 had a decrease in EET formation in BALF. We also verified that EET release was not due to cell death because the cell viability remained the same among the groups. Conclusion We revealed that the decrease in cysLT production or cysLT1 receptor inhibition by MK-886 or/and MK-571 treatments, respectively reduced EET formation in BALF, showing that cysLT regulates the activation process of EET release in asthma.
Toxicology, Jan 15, 2016
Ureases of Canavalia ensiformis are natural insecticides with a still elusive entomotoxic mode of... more Ureases of Canavalia ensiformis are natural insecticides with a still elusive entomotoxic mode of action. We have investigated the mechanisms involved in the neurotoxicity induced by Jack Bean Urease (JBU) in Nauphoeta cinerea (Olivier). To carry out this study we have employed biochemical and neurophysiological analysis of different cockroach organ systems. The injection of the insects with JBU (0.75 to 6μg/g animal), although not lethal within 24h, caused significant inhibition of the brain acetylcholinesterase activity (60±5%, p<0.05, n=6). JBU (1.5μg/200μL), acetylcholine (0.3μg/200μL) or neostigmine (0.22μg/200μL), induced a positive cardiac chronotropism (∼25%) in the cockroaches (p<0.05, n=9). JBU (6μg/g) increased the insects' grooming activity (137±7%), similarly to octopamine (15μg/g)…
Chemico-biological interactions, Jan 17, 2016
Animal venoms have been widely recognized as a major source of biologically active molecules. Bot... more Animal venoms have been widely recognized as a major source of biologically active molecules. Bothriurus bonariensis, popularly known as black scorpion, is the arthropod responsible for the highest number of accidents involving scorpion sting in Southern Brazil. Here we reported the first attempt to investigate the neurobiology of B. bonariensis venom (BBV) in the insect and mammalian nervous system. BBV (32 μg/g) induced a slow neuromuscular blockade in the in vivo cockroach nerve-muscle preparations (70 ± 4%, n = 6, p < 0.001), provoking repetitive twitches and significantly decreasing the frequency of spontaneous leg action potentials (SNCAPs) from 82 ± 3 min(-1) to 36 ± 1.3 min(-1) (n = 6, p < 0.05), without affecting the amplitude. When tested in primary cultures of rat hippocampal cells, BBV induced a massive increase of Ca(2+) influx (250 ± 1% peak increase, n = 3, p < 0.0001). The disturbance of calcium homeostasis induced by BBV on the mammalian central nervous sys...
Journal of Cellular Physiology, 2019
Studies have shown autophagy participation in the immunopathology of inflammatory diseases. Howev... more Studies have shown autophagy participation in the immunopathology of inflammatory diseases. However, autophagy role in asthma and in eosinophil extracellular traps (EETs) release is poorly understood. Here, we attempted to investigate the autophagy involvement in EETs release and in lung inflammation in an experimental asthma model. Mice were sensitized with ovalbumin (OVA), followed by OVA challenge. Before the challenge with OVA, mice were treated with an autophagy inhibitor, 3‐methyladenine (3‐MA). We showed that 3‐MA treatment decreases the number of eosinophils, eosinophil peroxidase (EPO) activity, goblet cells hyperplasia, proinflammatory cytokines, and nuclear factor kappa B (NFκB) p65 immunocontent in the lung. Moreover, 3‐MA was able to improve oxidative stress, mitochondrial energy metabolism, and Na+, K+‐ATPase activity. We demonstrated that treatment with autophagy inhibitor 3‐MA reduced EETs formation in the airway. On the basis of our results, 3‐MA treatment can be an...
Brazilian Oral Research, 2016
The aim of this study was to evaluate the thickness of resin cements in the root thirds when usin... more The aim of this study was to evaluate the thickness of resin cements in the root thirds when using conventional fiberglass posts (CP) and relined fiberglass posts (RP) in weakened roots and to evaluate the morphological characteristics of the dentin-resin interface. Forty human maxillary anterior teeth had the crown sectioned below the cemento-enamel junction. The canals were endodontically treated and weakened with diamond burs. Teeth were divided into four groups (n = 10): Group 1-CP + RelyX ARC; Group 2-CP + RelyX U200; Group 3-RP + RelyX ARC; and Group 4-RP + RelyX U200. Prior to luting, 0.1% Fluorescein and 0.1% Rhodamine B dyes were added to an adhesive and resin cement, respectively. Slices were obtained from the apical, middle, and cervical thirds of the root. Confocal laser scanning microscopy images were recorded in four areas (buccal, lingual, mesial, distal) of each third. In each area, four equidistant measures of the resin cement were made and the mean value was calculated. The interface morphology was observed. The data were submitted to three-way ANOVA and Tukey's test (α = 0.05). The interaction between fiberglass posts, resin cement, and root thirds was significant (p < 0.0001). The resin cement thicknesses were significantly lower for RP in comparison with CP, except in the apical third. There was no significant difference between the resin cements for RP. There was formation of resin cement tags and adhesive tags along the root for RP. RP favored the formation of thin and uniform resin cement films and resin tags in weakened roots.
Nos últimos anos tem-se proposto que a hiperexcitabilidade na Epilepsia do Lobo Temporal é atribu... more Nos últimos anos tem-se proposto que a hiperexcitabilidade na Epilepsia do Lobo Temporal é atribuída, pelo menos em parte, a função aumentada de uma subpopulação de sinapses glutamatérgicas que utilizam receptores NMDA (NMDAr). O envolvimento do NMDAr pode ser observado através da adição do APV (DL-2-amino-5fosfonovalerato, antagonista do NMDA) antes, durante e depois do tratamento com o modelo do Ringer sem magnésio (Ringer 0-Mg 2+). O objetivo deste estudo é testar a hipótese que os NMDAr possam alterar propriedades eletrofisiológicas de neurônios hipocampais de CA1, em tecido humano. As fatias de hipocampo humano foram obtidas de amostras de tecidos cerebrais removidas durante o procedimento cirúrgico para o tratamento de epilepsia refratária. Ainda no bloco cirúrgico a amostra foi fatiada (500μm) com auxílio de um vibrátomo mantidas imersas em uma cuba com solução de Ringer normal (líquido cefalorraquidiano artificial) em temperatura ambiente, continuamente oxigenadas (95% O 2 e 5% de CO 2). Posteriormente foram transferidas para uma câmara de interface para registro eletrofisiológico intra e extracelular dos neurônios hipocampais de CA1. Foram avaliadas as propriedades passivas da membrana (potencial de membrana, resistência de entrada e constante de tempo) e propriedades ativas (excitabilidade, limiar para o disparo, amplitude e potencial de repolarização) em três momentos antes, durante e depois da perfusão com o Ringer 0-Mg 2+. Este modelo provocou o aparecimento de descargas espontâneas simples ou em salva em 75% dos neurônios de CA1 estudados. Foram observados ainda que 25% dos neurônios hipocampais não responderam a perfusão com Ringer 0-Mg 2+ , além de não apresentaram alterações nas propriedades avaliadas (n:30). De acordo com os dados adquiridos os receptores NMDA em meio ausente de Mg 2+ não induzem alterações eletrofisiológicas em humanos. (PUCRS, UFRGS, Fapergs, CNPq, CAPES, SC&T RS).
J. epilepsy clin. …, 2002
Base de dados : LILACS. Pesquisa : 431943 [Identificador único]. Referências encontradas : 1 [ref... more Base de dados : LILACS. Pesquisa : 431943 [Identificador único]. Referências encontradas : 1 [refinar]. Mostrando: 1 .. 1 no formato [Detalhado]. página 1 de 1, 1 / 1, LILACS, seleciona. para imprimir. Fotocópia. experimental, Documentos relacionados. Id: 431943. ...
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Papers by Ricardo V Breda