Rodrigo Mariano

N-Acetylcysteine administration confers lung protection in different phases of lung ischaemia–reperfusion injury

OBJECTIVES To verify the effects of N-acetylcysteine (NAC) administered before and after ischaemia in an animal model of lung ischaemia-reperfusion (IR) injury. METHODS Twenty-four Wistar rats were subjected to an experimental model of selective left pulmonary hilar clamping for 45 min followed by 2 h of reperfusion. The animals were divided into four groups: control group (SHAM), ischaemia-reperfusion, N-acetylcysteine-preischaemia (NAC-Pre) and NAC-postischaemia (NAC-Post). We recorded the haemodynamic parameters, blood gas analysis and histology. We measured the thiobarbituric acid reactive substances concentration; the expression of superoxide dismutase (SOD), inducible nitric oxide synthase (iNOS), nitrotyrosine, cleaved caspase 3, nuclear factor κB (NF-κB), NF-kappa-B inhibitor alpha (IκB-α), tumour necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β); myeloperoxidase activity (MPO). RESULTS No significant differences were observed in the haemodynamic parameters, blood gas analysis and SOD activity among the groups. Lipid peroxidation was significantly higher in the IR and NAC-Pre groups (P < 0.01). The expression of nitrotyrosine, cleaved caspase 3, NF-κB, IκB-α, TNF-α and IL-1β were significantly higher in the IR group when compared with the SHAM and NAC groups (P < 0.01). The NAC-Pre group showed a significantly higher expression of these proteins when compared with the SHAM and NAC-Post groups (P < 0.05). After reperfusion, the expression of iNOS increased almost uniformly in all groups when compared with the SHAM group (P < 0.01). The histological analysis showed fewer inflammatory cells in the NAC groups. CONCLUSIONS The intravenous administration of NAC demonstrated protective properties against lung IR injury. The use of NAC immediately after reperfusion potentiates its protective effects.

Endobronchial perfluorocarbon administration decreases lung injury in an experimental model of ischemia and reperfusion

OBJECTIVE To verify the effects of liquid endobronchial perfluorocarbon (PFC) administered before reperfusion in an animal model of lung ischemia-reperfusion injury. METHODS Eighteen Wistar rats were subjected to an experimental model of selective left pulmonary artery clamping for 45 min followed by reperfusion for 2 h. The animals were divided into three groups: the ischemia-reperfusion (IR) group, the sham group, and the PFC group. We recorded the hemodynamic parameters, blood gas analysis, and histology. A Western blot assay was used to measure the inducible nitric oxide synthase, caspase 3, and nuclear factor қB (subunit p65) activities. Lipid peroxidation was assessed by the thiobarbituric acid reactive substances assay and the activity of the antioxidant enzyme superoxide dismutase. RESULTS No significant differences were observed in lipid peroxidation among the groups. The superoxide dismutase activity was increased (P < 0.05) in the PFC-treated group. The expressions of nuclear factor қB, inducible nitric oxide synthase, and caspase 3 were significantly lower in the PFC group than in the IR group (P < 0.05). The histologic analysis showed a reduction in lung injuries in the PFC group compared with the sham and IR groups. CONCLUSION The use of endobronchial PFC reduces the inflammatory response, preserves the alveolar structure, and protects the lungs against the hazardous effects of ischemia-reperfusion injuries.

The potential role of extracellular regulatory kinase in the survival of patients with early stage adenocarcinoma

BACKGROUND Lung cancer is among the most common types of neoplasias, and adenocarcinoma is the most frequent histological type. There is currently an extensive search for prognostic biomarkers of nonsmall cell lung cancer (NSCLC). METHODS We analyzed the correlation of clinical data and patient survival with the levels of activated extracellular regulatory kinase (ERK) in histological samples of surgically resected early stage lung adenocarcinoma. We randomly selected 36 patients with stage I or II lung adenocarcinoma who underwent pulmonary lobectomy between 1998 and 2004. Patients were divided into the following two groups according to immunohistochemical profile: a group with <15% ERK-positive tumor cells and a group with ≥15% ERK-positive tumor cells. For data comparison, an enrichment analysis of a microarray database was performed (GSE29016, n=72). RESULTS Activated ERK levels were ≥15% and <15% in 21 (58%) and 15 (42%) patients, respectively. There were no statistically significant differences in age, sex, smoking history, and body mass index (BMI) among the groups stratified by ERK levels. The survival rate was lower in the ERK ≥15% group than in the ERK <15% group (P=0.045). Enrichment analyses showed no correlation between variations in gene expression of ERK in patients with adenocarcinoma and survival rates in patients with stage I and combined stage II + III disease. CONCLUSIONS Our findings suggest that high ERK positivity in cells from biological samples of lung adenocarcinoma is related with tumor aggressiveness and a poorer prognosis.

Effectiveness of diaphragmatic stimulation with single-channel electrodes in rabbits

Every year, a large number of individuals become dependent on mechanical ventilation because of a loss of diaphragm function. The most common causes are cervical spinal trauma and neuromuscular diseases. We have developed an experimental model to evaluate the performance of electrical stimulation of the diaphragm in rabbits using single-channel electrodes implanted directly into the muscle. Various current intensities (10, 16, 20, and 26 mA) produced tidal volumes above the baseline value, showing that this model is effective for the study of diaphragm performance at different levels of electrical stimulationEvery year, a large number of individuals become dependent on mechanical ventilation because of a loss of diaphragm function. The most common causes are cervical spinal trauma and neuromuscular diseases. We have developed an experimental model to evaluate the performance of electrical stimulation of the diaphragm in rabbits using single-channel electrodes implanted directly into the muscle. Various current intensities (10, 16, 20, and 26 mA) produced tidal volumes above the baseline value, showing that this model is effective for the study of diaphragm performance at different levels of electrical stimulation

Technique for implanting intramuscular electrodes in the diaphragm by videolaparoscopy in pigs

PURPOSE To describe a novel approach for implanting intramuscular electrodes in the diaphragm through videolaparoscopy. METHODS We used twelve pigs for this videolaparoscopic technique, which permits at the same time to explore the diaphragm, to locate its motor points and to fix the electrodes in the diaphragm bilaterally. In this technique we used three trocars: one portal for a 10-mm 0° viewing angle laparoscope, one portal for the manipulation of structures and another for electrode implantation. RESULTS All animals survived the procedure without pneumothorax/capnothorax or other complication. Implanted electrodes provided an appropriate interface between the muscle and the electrical current generator, and electroventilation was satisfactorily generated in all animals. CONCLUSION This videolaparoscopic technique with three trocars enables the exploration and identification of motor points and an efficient fixation of one or two electrodes in each hemidiaphragm.