Continuous and not continuous 2-week treadmill training enhances the performance in the passive avoidance test in ischemic gerbils.

This study aims to investigate the frequency and total duration effects of the 2-week treadmill training after experimental ischemic stroke in the passive avoidance test. We performed bilateral occlusion of common external carotid arteries, for five minutes, in Mongolian gerbils. The training groups were: continuous training for twelve consecutive days or not continuous training for six non-consecutive days. The groups remained in the treadmill for 15min, with the speed set at 10m/min, and the training started 24h after the stroke. In the Shuttle Box, each animal had ten trials during the Learning Session (LS), which occurred 24h before the stroke. The Retention Test (RT) occurred 24h after the stroke and started on the second, third, seventh and twelfth day after LS. After the experiments, the brains were perfused, and coronal sections of the CA1 area of the hippocampus were cut and stained with hematoxylin and eosin. ANOVA on Ranks was used for Behavioral data analysis and morphological data by percentage. Ischemic training groups showed preservation in neuron density in the CA1 area of the hippocampus, when compared to the control groups. Animals subjected to continuous training, showed a higher latency in the RT when compared to ischemic animals in both weeks [(2nd, H=39.81; P<0.05), (3rd, H=38.08; P<0.05), (7th, H=44.17; P<0.05), and (12th, H=39.55; P<0.05). Animals in the not continuous training showed higher latency in the RT, in the second week only [(2nd, H=39.81; P<0.05), (3rd, H=38.08; P<0.05), (7th, H=44.17; P<0.05), and (12th, H=39.55; P<0.05). These findings suggest that improvement of memory after stroke after treadmill training is dependent on the frequency and total duration of training.

An adaptation for exhaled breath condensate collection in rabbits.

AIM: To set up and test the feasibility of a handmade apparatus adapted for exhaled breath condensate (EBC) collection in medium-sized animals. MATERIALS AND METHODS: The apparatus was produced using an 18-mm thick u-shaped borosilicate glass. The u-shaped tube body is 25 cm in diameter, and the horizontal portions are 12 cm in diameter. The base consists of a tube joint 14/20 or 14 mm thick by 20 cm in diameter, and has a length of 5 cm. This has a hole that is plugged for condensate flow to a 1.5 mL polypropylene microtube that stores the condensate during collection. Was placed inside a styrofoam box and immersed in crushed ice and salt to ensure cooling. The temperature was monitored and maintained throughout the collection at -10°C. One of the outputs of the u-shaped tube was connected to the expiratory limb of the ventilator. RESULTS: An experimental model of ALI, induced by oleic acid (OA) was adopted to determine the concentration of biomarkers of oxidative stress: malondialdehyde (MDA), glutathione (GSH), and nitrite/nitrate (NOx). The proposed model allows measurement of NOx, MDA, and GSH. However, the NOx and MDA levels in the EBC were not significant. It was only possible to observe an upward trend, which suggests a temporal evolution of the presence of these markers in the EBC. CONCLUSION: The EBC collection method adapted is effective to generate sufficient content that allows to determine the levels of different biomarkers, such as NOx, MDA, and GSH, that are involved in oxidative and inflammatory stress processes during respiratory diseases.

High conductance potassium channels activation by acid exposure in rat aorta is endothelium-dependent.

BACKGROUND: We investigated, previously, the mechanism by which extracellular acidification promotes relaxation in rat thoracic aorta. These studies suggested that extracellular acidosis promotes vasodilation mediated by NO, KATP and SKCa, and maybe other K(+) channels in isolated rat thoracic aorta. This study was carried out to investigate the paxilline-mediated hyperpolarization induced by acid exposure. RESULTS: The relaxation response to HCl-induced extracellular acidification (7.4-6.5) was measured in rat aortic rings pre-contracted with phenylephrine (PE, 10(-6) M). The vascular reactivity experiments were performed in endothelium-intact and denuded rings, in the presence of paxilline (10(-6) M), which is an inhibitor of high calcium conductance potassium BKCa channels. In rings with endothelium, paxilline inhibits relaxation, triggered by acidification at all pH values lower than 7.2 and had no effect on rings without endothelium, showing that the activation of BKCa is endothelium-dependent. CONCLUSION: High conductance potassium channel activation induced by acid exposure is endothelium-dependent.

Presentation of an experimental method to induce in vitro ("organ chambers") respiratory acidosis and its effect on vascular reactivity.

PURPOSE: To create in vitro a model to generate acidosis by CO2 bubbling "organ chambers", which would be useful for researchers that aim to study the effects of acid-base disturbs on the endothelium-dependent vascular reactivity. METHODS: Eighteen male Wistar rats (230-280 g) were housed, before the experiments, under standard laboratory conditions (12h light/dark cycle at 21°C), with free access to food and water. The protocol for promoting in vitro respiratory acidosis was carried out by bubbling increased concentrations of CO2. The target was to achieve an ideal way to decrease the pH gradually to a value of approximately 6.6.It was used, initially, a gas blender varying concentrations of the carbogenic mixture (95% O2 + 5% CO2) and pure CO2. RESULTS: 1) 100% CO2, pH variation very fast, pH minimum 6.0; 2) 90%CO2 pH variation bit slower, pH minimum 6.31; 3) 70%CO2, pH variation slower, pH minimum 6.32; 4) 50% CO2, pH variation slower, pH minimum 6:42; 5) 40 %CO2, Adequate record, pH minimum 6.61, and; 6) 30 %CO2 could not reach values below pH minimum 7.03. Based on these data the gas mixture (O2 60% + CO2 40%) was adopted. CONCLUSION: This gas mixture (O2 60% + CO2 40%) was effective in inducing respiratory acidosis at a speed that made, possible the recording of isometric force.

Presentation of an experimental method to induce in vitro ("organ chambers") respiratory acidosis and its effect on vascular reactivity

PURPOSE: To create in vitro a model to generate acidosis by CO2 bubbling "organ chambers", which would be useful for researchers that aim to study the effects of acid-base disturbs on the endothelium-dependent vascular reactivity. METHODS: Eighteen male Wistar rats (230-280g) were housed, before the experiments, under standard laboratory conditions (12h light/dark cycle at 21°C), with free access to food and water. The protocol for promoting in vitro respiratory acidosis was carried out by bubbling increased concentrations of CO2. The target was to achieve an ideal way to decrease the pH gradually to a value of approximately 6.6.It was used, initially, a gas blender varying concentrations of the carbogenic mixture (95% O2 + 5% CO2) and pure CO2. RESULTS: 1) 100% CO2, pH variation very fast, pH minimum 6.0; 2) 90%CO2 pH variation bit slower, pH minimum6.31; 3) 70%CO2, pH variation slower, pH minimum 6.32; 4) 50% CO2, pH variation slower, pH minimum 6:42; 5) 40 %CO2, Adequate record, pH minimum 6.61, and; 6) 30 %CO2 could not reach values below pH minimum 7.03. Based on these data the gas mixture (O2 60% + CO2 40%) was adopted, CONCLUSION: This gas mixture (O2 60% + CO2 40%) was effective in inducing respiratory acidosis at a speed that made, possible the recording of isometric force. .

In vitro effects of the organophosphorus pesticide malathion on the reactivity of rat aorta.

BACKGROUND AND PURPOSE: There is a remarkable paucity of studies analyzing the role of the endothelium-derived relaxing factors on the vascular effects of organophosphates. This study was carried out to evaluate the vascular effects of malathion and the role of nitric oxide (NO) and prostacyclin (PGI2). METHODS: Vascular reactivity measuring isometric forces in vitro ('organ chambers') and flow cytometry (cells loaded with DAF-FM DA) were used. RESULTS: In rat thoracic aorta segments contracted with phenylephrine (Phe) (10(-7) mol/l), malathion (10(-10) to 10(-5) mol/l) induced concentration-dependent relaxation in arteries with intact endothelium (n = 7; p < 0.05). Malathion-mediated relaxation was blocked by N-nitro-L-arginine methyl ester (L-NAME; 10(-4) mol/l), a nonspecific NO synthase inhibitor, and/or indomethacin (10(-5) mol/l), a nonspecific cyclooxygenase inhibitor (n = 10, p < 0.05). In thoracic aorta rings, with and without endothelium, Phe (10(-10) to 10(-5) mol/l) evoked concentration-dependent contraction, which was reduced in the presence of malathion. In rings with or without endothelium, incubated with malathion, L-NAME and indomethacin, the Phe-induced contraction was restored. The role of NO was confirmed using flow cytometry. Malathion evokes endothelium-dependent relaxation through the M1 muscarinic receptor, since this relaxation was clearly blocked by atropine (M1 and M2 blocker) and pirenzepine (M1 blocker), but was less blocked by gallamine (M2 blocker) or 4-DAMP (M3 blocker). CONCLUSIONS: These findings suggest that the organophosphate compound effects on vascular reactivity depend of NO and PGI2.

Comparação do uso da pressão positiva com a fisioterapia convencional e incentivadores respiratórios após cirurgia cardíaca: revisão de literatura / Comparison of using the positive pressure, conventional physiotherapy and incentive spirometry after cardiac surgey: literature review

A cirurgia cardíaca (CC) tem sido um procedimento que possibilita a remissão dos sintomas, contribui para o aumento da sobrevida e melhora da qualidade de vida de cardiopatas, porém complicações pulmonares (CP) podem ser encontradas no pós-operatório de CC. A fisioterapia respiratória é utilizada na prevenção e tratamento das CP através de técnicas capazes de otimizar a mecânica respiratória, a reexpansão pulmonar e a higiene brônquica. O presente estudo tem como objetivo realizar uma revisão da literatura comparando a aplicação da pressão positiva contínua nas vias aéreas (CPAP), pressão positiva contínua em dois níveis pressóricos nas vias aéreas (BiPAP) e respiração com pressão positiva intermitente (RPPI) com as técnicas de fisioterapia convencional (FIC) e incentivador respiratório (IR). Foram utilizadas como referências publicações em inglês e português com descritores específicos ao tema, buscando-os nas seguintes fontes de dados: BIREME, SciELO Brazil, LILACS, PUBMED, de 1991 até 2010. Posteriormente foi realizada uma pesquisa secundária utilizando-se as referências dos artigos encontrados. Dentre os artigos encontrados foram selecionados nove ensaios clínicos randomizados e duas revisões de literatura. Em dois estudos a modalidade CPAP e BiPAP mostrou-se mais efetiva do que a FIC e o IR, enquanto que em outro demonstrou-se a superioridade do BiPAP em relação ao uso de catéter de oxigênio. Apenas um estudo demonstrou superioridade estatisticamente significante do RPPI sobre o CPAP. Contudo, não existe consenso acerca da melhor técnica de fisioterapia a ser utilizada. Também foi verificado que ao comparar as diferentes modalidades de ventilação não invasiva, não se pôde afirmar que uma apresenta superioridade em relação às outras. Ressalta-se que nenhum dos estudos encontrados comparou as três modalidade, BiPAP, CPAP e RPPI.

Cardiac surgery (CS) provides remission of symptoms, contributes to increased survival and improved quality of life in cardiac patients, but pulmonary complications (PC) can be found in postoperative of CS. Respiratory physiotherapy is used to prevent and treat PC through techniques that optimize respiratory mechanics, pulmonary reexpansion and bronchial hygiene. The aim of the present study was to make a literature review comparing the use of continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP) and intermittent positive pressure breathing (IPPB) with conventional physiotherapy (CP) and incentive spirometry (IS). Publications in english and portuguese were used as references, searching for specific descriptors about the theme in the following data sources: BIREME, SciELO Brazil, LILACS, PUBMED, from 1991 until 2010. Also a secondary search was performed using the references list of selected articles. Among articles found, nine randomized control trial and two literature review were selected. The modalities CPAP e BiPAP were more effective than CP and IS in two studies, however, other study showed BiPAP was superior to nasal oxygen catheter. Only one article showed IPPB was statistically significant superior to CPAP. However, there is no consensus in the literature about the most effective physiotherapy technique. The present study also compared different modalities of non-invasive ventilation, but the superiority of one modality over another could not be established. It is important to emphasize that no selected article compared three modalities, BiPAP, CPAP and IPPB.