Papers by Paulo Roberto Barbosa Evora
Current Drug Targets
Reperfusion of ischemic tissue reinstitutes oxygenation and substrates that are essential for the... more Reperfusion of ischemic tissue reinstitutes oxygenation and substrates that are essential for the recovery of hypoxemic tissues while simultaneously removing ac
Vasoplegic Endothelial Dysfunction, 2021
Although methylene blue (MB) has been used for more than 20 years in the treatment of vasoplegic ... more Although methylene blue (MB) has been used for more than 20 years in the treatment of vasoplegic syndrome (VS), few quality clinical studies can allow the procedure to become a protocol. The pathophysiology of vasoplegia after cardiopulmonary bypass is multifactorial, with no final consensus on its real mechanism. For didactic purposes, emphasis will be given to three aspects, which are the most mentioned in clinical and laboratory studies on the subject: (a) the systemic inflammatory reaction; (b) the effects of protamine; and (c) a new mechanism recently related to the impairment of vasopressin receptors. There is strong evidence that MB, a guanylate cyclase inhibitor, is an excellent therapeutic option for the treatment of VS in cardiac surgery. Our clinical and laboratory experience, accumulated over a period of 20 years, established some classic concepts about the use of MB in this condition.
Brazilian Journal of Biology, 2024
This study was carried out to evaluate the effect of Glutamine, as a dipeptide or a free amino ac... more This study was carried out to evaluate the effect of Glutamine, as a dipeptide or a free amino acid form, on the progression of burn injuries in rats. Thirty male Wistar rats were burned with a comb metal plate heated in boiling water (98 °C) for three minutes, creating four rectangular full-thickness burn areas separated by three unburned interspaces (zone of stasis) in both dorsum sides. The animals were randomized into three groups (n=10): saline solution (G1-Control) and treated groups that orally received Glutamine as dipeptide (G2-Dip) or free amino acid (G3-FreeAA). Two and seven days after burn injury, lesions were photographed for unburned interspaces necrosis evolution assessment. Seven days after injury, glutathione seric was measured and histopathological analysis was performed. By photographs, there was a significant reduction in necrosis progression in G3-Free-AA between days two and seven. Histopathological analysis at day 7 showed a significantly higher stasis zone w...
Journal of Wound Care, 2021
Objective: A burn injury has two defined areas: central necrosis and an adjacent area of ischaemi... more Objective: A burn injury has two defined areas: central necrosis and an adjacent area of ischaemia, which may or may not progress to necrosis. The concentration of nitric oxide (NO) increases after burn injury and may originate from potent oxidising agents. Methylene blue (MB) may act as an antioxidant and is supposed to reduce burn progression. This investigation was carried out to evaluate the effects of intradermal MB on necrosis progression in burns. Methods: Full-thickness burn injuries were performed by applying a heated metal comb on the shaved back of male Wistar rats. The animals were divided into three groups: Control (C, n=7); MB (2mg/kg) one hour after burn injury (MB1h, n=11); and MB (2mg/kg) six hours after burn injury (MB6h, n=8). After seven days the lesions were photographed for visual assessment of burn necrosis; full-thickness cuts of lesions were dyed with Masson and Giemsa for microscopic histopathology; and tissue fragments of unburned interspaces were processe...
Brazilian Journal of Biology, 2021
Acta Cirurgica Brasileira, 2018
Early cancer diagnosis, new therapies that increased survival of patients, besides the increasing... more Early cancer diagnosis, new therapies that increased survival of patients, besides the increasingly elderly population are some factors would be associated with possible cancer dissemination in patients under cardiopulmonary bypass (CPB) cardiac surgery. Also, the benefits, and risks, regarding long-term survival, have not yet been established. Therefore, cardiac surgery morbimortality may be superior in patients with cancer disease. Also, immunologic and inflammatory changes secondary to CPB can also increase tumor recurrence. After a brief introduction and CPB immunologic the two main topic subjects included: 1) Combined heart surgery and lung resection and; 2) Possible influence of neoplasia type. After observing the relative literature scarcity, we keep the opinion that "CPB has a modest association with cancer progression" and that "CPB and cancer dissemination should be a logical but unlikely association."
Brazilian Journal of Cardiovascular Surgery, 2016
The objective of this study covers only the development of the needle and the histological qualit... more The objective of this study covers only the development of the needle and the histological quality of the biopsies. A previous note was published in this journal [1]. DESCRIPTION OF TECHNOLOGY The instrument for puncturing and injecting biological material is composed of an external needle (1), called coupling infusion, which contains a blunt tip (2) and multiple 0.5 mm diameter holes (3) at its end. Internally, it is fitted with a blunt mandrel that can be mobilized to fill the lateral holes, occluding or releasing them. The procedure for producing microlesions is done by replacing the blunt mandrel with a brush-mandrel (4), structurally designed to fill the holes by exteriorizing the small bristles (5) (Figure 1). The instrument is equipped with a locking mechanism that allows its complete mobilization as one single unit for microlesions. It can also be used simply as an external needle, thus becoming an instrument for biological injection. It was designed with an optional feather-mandrel (Figure 2).
Experimental Lung Research, 2016
To set up and test the feasibility of a handmade apparatus adapted for exhaled breath condensate ... more To set up and test the feasibility of a handmade apparatus adapted for exhaled breath condensate (EBC) collection in medium-sized animals. 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. 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. 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.
Annals of Translational Medicine, 2016
The present text was motivated by the difficulties faced by our postgraduate students when using ... more The present text was motivated by the difficulties faced by our postgraduate students when using airways studies protocols and will take into consideration the three mechanisms of relaxation: (I) guanosine 3,5-cyclic monophosphate (cGMP)/NO-dependent; (II) adenosine 3,5-cyclic monophosphate (cAMP)/PGI2-dependent, and (III) hyperpolarization-dependent. Tracheal rings are studied in an organ bath containing a gassed physiological salt solution, usually at a temperature of 37 ℃. An agent or procedure that causes contraction [acetylcholine (Ach) or metacholine] of the smooth muscle is needed before study airway dilator drugs. The presented airways studies protocols are useful to study the bronchial epithelial-dependent reactivity.
Revista eletrônica de Farmácia, Dec 27, 2012
Introduction: The organophosphorus (OF) compounds are chemicals present in pesticides and are kno... more Introduction: The organophosphorus (OF) compounds are chemicals present in pesticides and are known as acetylcholinesterase (AchE) inhibitors. The main toxic action of organophosphates includes the inhibition of cholinesterase enzyme promoting muscarinic, nicotinic and central effects. In the cardiovascular system, nicotinic manifestations are tachycardia and hypertension, while the muscarinic are bradycardia and hypotension. In the respiratory system cholinesterase, inhibition is characterized by increased bronchial secretions, bronchospasm and occurrence of paralysis of respiratory muscles. Although the effects of the organophosphates are best known due to inhibition of cholinesterase, in vitro studies have demonstrated its vasodilator effect and constriction of the airways, suggesting that these compounds may have a peripheral action independent of its effect on the enzyme that degrades acetylcholine. A better understanding of the toxic effects of organophosphates on the vascular system and respiratory systems, independent of cholinesterase inhibition, could open new perspectives for a more effective treatment directed to the major causes of death (respiratory failure and impaired cardiovascular function) in victims of poisoning these compounds. Objective: This study was carried out to evaluate the effect of the organophosphate Malathion, on the reactivity of isolated rat aorta as well as the mechanisms involved in this response, with special attention to the participation of nitric oxide (NO). Material and Methods: We studied vascular reactivity in aorta isolated from male Wistar rats, weighing between 250 and 300, by measuring isometric force "organ chambers" using log concentration-response curves obtained after administration of Fenthion and Malathion in rings with and without endothelium pre-contracted with phenylephrine (Phe). As part of the experimental protocol were also performed contraction curves to Phe in the presence and absence of organophosphates, in rings with and without endothelium, and finally, the relaxation curves to ACh in the presence and absence of organophosphates in rings with endothelium. Curves were also performed in the presence of indomethacin (cyclooxygenase inhibitor), and Nω-nitro-L-arginine methyl ester (L-NAME-nonspecific inhibitor of nitric oxide synthase). Results: the organophosphate Fenthion does not promote vasodilation and does not alter the vascular response induced by Phe or Ach. In contrast, the organophosphate Malathion had a relaxing effect only in rings with endothelium and, in rings with and without endothelium, induced a considerable decrease in Phe-induced contraction. From these results, we decided to continue the studies involving the organophosphate Malathion, which evoked endothelium-dependent relaxation. In the presence of indomethacin and L-NAME, Malathion relaxation in endothelium-rings was inhibited, and the reduction of the contraction to Phe, was reversed. Conclusion: Malathion promotes relaxation endothelium-dependent mediated by NO and prostanoids and reduces the ability of calcium-dependent vasoconstrictors to exert its effect. As the effects of L-NAME and indomethacin were similar and not shown a significant enhancing effect when used in combination, we can suggest the occurrence of a crosstalk between the pathways of cyclooxygenase and NO in the vascular effects induced by the organophosphate Malathion.
BMC Research Notes, 2015
Background: We investigated, previously, the mechanism by which extracellular acidification promo... more 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, K ATP and SK Ca , 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 endotheliumintact and denuded rings, in the presence of paxilline (10 −6 M), which is an inhibitor of high calcium conductance potassium BK Ca 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 BK Ca is endothelium-dependent. Conclusion: High conductance potassium channel activation induced by acid exposure is endothelium-dependent.
Annales de Chirurgie Vasculaire, 2007
Etude pharmacologique in vitro de la ré activité vasculaire de l'artè re fé morale aprè s isché m... more Etude pharmacologique in vitro de la ré activité vasculaire de l'artè re fé morale aprè s isché mie/reperfusion de la patte posté rieure chez le chien : effets de la perfusion in vivo d'un bloqueur de l'oxyde nitrique
Acta Cirurgica Brasileira, 2004
O transplante hepático tornou-se o procedimento de escolha para o tratamento da doença hepática t... more O transplante hepático tornou-se o procedimento de escolha para o tratamento da doença hepática terminal. Não obstante o sucesso da cirurgia, a disfunção pós-operatória do fígado enxertado ainda representa importante causa de morbidade e mortalidade. O restabelecimento do fluxo sangüíneo ao fígado recém transplantado impõe a ele nova agressão, agravando a lesão causada pelo período de isquemia. Este fenômeno pouco compreendido é conhecido como lesão por isquemia e reperfusão e envolve disfunção endotelial, seqüestro de leucócitos e agregação de plaquetas, lesão por radicais livre de oxigênio, e distúrbios da microcirculação hepática. Essa revisão discute os vários aspectos fisiopatológicos que estão envolvidos na lesão por isquemia e reperfusão do fígado.
Acta Cirurgica Brasileira, 2013
PURPOSE: The rationale of the present review is to analize the activity of Rosmarinus officinalis... more PURPOSE: The rationale of the present review is to analize the activity of Rosmarinus officinalis in the the cardiovascular system METHODS: A MEDLINE database search (from January 1970 to December 2011) using only rosmarinic acid as searched term. RESULTS: The references search revealed 509 references about rosmarinic acid in 40 years (the first reference is from 1970). There is a powerful prevalence of antioxidant and cancer studies. Other diseases are few cited, as inflammation, brain (Alzheimer and Parkinson disease) and, memory; allergy; diabetes; atherosclerosis, and; hypertension. It is necessary to consider the complete absence of studies on coronary artery disease, myocardial ischemia, heart failure or ischemia/reperfusion injury. CONCLUSION: Rosmarinic acid is underestimated as an experimental cardiovascular drug and deserves more attention.
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Papers by Paulo Roberto Barbosa Evora