Protective effects of diphenyleneiodonium,an NADPH oxidase inhibitor,on lipopolysaccharide‐induced acute lung injury

NADPH oxidase (NOX) plays an important role in inflammatory response by producing reactive oxygen species (ROS). The inhibition of NOX has been shown to induce anti‐inflammatory effects in a few experimental models. The aim of this study was to investigate the effects of diphenyleneiodonium (DPI), a NOX inhibitor, on lipopolysaccharide (LPS)‐induced acute lung injury (ALI) in a rat model. Sprague‐Dawley rats were intraperitoneally administered by DPI (5 mg/kg) 30 minutes after intratracheal instillation of LPS (3 mg/kg). After 6 hours, bronchoalveolar lavage fluid (BALF) and lung tissue were collected. The NOX activity in lung tissue was significantly increased in LPS‐treated rats. It was significantly attenuated by DPI. DPI‐treated rats showed significant reduction in the intracellular ROS, the number of inflammatory cells, and cytokines (TNF‐α and IL‐6) in BALF compared with LPS‐treated rats. In lung tissue, DPI‐treated rats showed significantly decreased malondialdehyde content and increased activity of glutathione peroxidase and superoxide dismutase compared with LPS‐treated rats. Lung injury score, myeloperoxidase activity, and inducible nitric oxide synthase expression were significantly decreased in DPI‐treated rats compared with LPS‐treated animals. Western blotting analysis demonstrated that DPI significantly suppressed LPS‐induced activation of NF‐κB and ERK1/2 and SAPK/JNK in MAPK pathway. Our results suggest that DPI may have protective effects on LPS‐induced ALI thorough anti‐oxidative and anti‐inflammatory effects which may be due to inactivation of the NF‐κB, ERK1/2, and SAPK/JNK pathway. These results suggest the therapeutic potential of DPI as an anti‐inflammatory agent in ALI.     

Utility of exit block for identifying electrical isolation of the pulmonary veins

INTRODUCTION: Electrical isolation of the pulmonary veins (PVs) to treat paroxysmal atrial fibrillation (AF) has been described using "entry block" as an endpoint for PV isolation. We describe a new technique for guiding PV isolation, using "exit block" out of the PV after ablation as a criterion for successful isolation. METHODS AND RESULTS: A circular mapping catheter was positioned at the os of arrhythmogenic PVs and ablation was performed proximal to the mapping catheter until entry block into the vein was achieved. Pacing was performed from the mapping catheter and from the ablator inside the PV to document exit block out of the PV. In patients in whom cardioversion did not restore sinus rhythm, PV isolation was performed in AF. Entry and exit block were reassessed in ablated veins after a 20-minute waiting period. Ninety-five PVs were ablated in 41 patients. A total of 66 PVs in 34 patients were ablated in sinus rhythm. After entry block was achieved, exit block was present in only 38 (58%) of 66 PVs. A total of 29 PVs in 21 patients were ablated in AF. After cardioversion to sinus rhythm, there was evidence of entry block into the PV in 20 (69%) of 29 PVs and exit block in only 14 (48%) of 29 PVs. There was no significant difference between the total number of lesions applied per vein in sinus rhythm compared with AF (11.6 +/- 8.6 vs 10.3 +/- 6.2; P = NS). There was recovery of conduction after a 20-minute waiting period in 9 (11%) of 84 PVs. CONCLUSION: Identification of exit block after ostial PV ablation provides a clear endpoint for electrical isolation of the PVs. Isolation of the PVs can be performed during sustained AF without the need to apply excess RF lesions. Applying a 20-minute waiting period after electrical isolation will identify reconnection in approximately 10% of PVs.     

Loss of EMP2 Inhibits Melanogenesis of MNT1 Melanoma Cells via Regulation of TRP-2

Melanogenesis is the production of melanin from tyrosine by a series of enzyme-catalyzed reactions, in which tyrosinase and DOPA oxidase play key roles. The melanin content in the skin determines skin pigmentation. Abnormalities in skin pigmentation lead to various skin pigmentation disorders. Recent research has shown that the expression of EMP2 is much lower in melanoma than in normal melanocytes, but its role in melanogenesis has not yet been elucidated. Therefore, we investigated the role of EMP2 in the melanogenesis of MNT1 human melanoma cells. We examined TRP-1, TRP-2, and TYR expression levels during melanogenesis in MNT1 melanoma cells by gene silencing of EMP2. Western blot and RT-PCR results confirmed that the expression levels of TYR and TRP-2 were decreased when EMP2 expression was knocked down by EMP2 siRNA in MNT1 cells, and these changes were reversed when EMP2 was overexpressed. We verified the EMP2 gene was knocked out of the cell line (EMP2 CRISPR/Cas9) by using a CRISPR/Cas9 system and found that the expression levels of TRP-2 and TYR were significantly lower in the EMP2 CRISPR/Cas9 cell lines. Loss of EMP2 also reduced migration and invasion of MNT1 melanoma cells. In addition, the melanosome transfer from the melanocytes to keratinocytes in the EMP2 KO cells cocultured with keratinocytes was reduced compared to the cells in the control coculture group. In conclusion, these results suggest that EMP2 is involved in melanogenesis via the regulation of TRP-2 expression.     

Chronic heart failure model in rabbits based on the concept of the bifurcation/trifurcation coronary artery branching pattern

The aim of this study was to develop a reliable chronic heart failure model by coronary artery ligation in the rabbit on the basis of the new concept of the bifurcation/trifurcation classification system of the epicardial branching pattern of the left coronary artery (LCA). New Zealand White rabbits (n = 37) were divided into 3 experimental groups: a posterolateral division of the bifurcation pattern of the LCA was ligated at the 75% level from the apex along the course of the division (B75 group, n = 15); a lateral division of the trifurcation pattern at the 75% level (T75 group, n = 11); and a posterolateral division of the bifurcation pattern at the 50% level (B50 group, n = 11). The infarct size and the lung and liver water content were determined at 4 weeks following ligation. The Q or QS wave on electrocardiogram (ECG) and the left ventricular (LV) dimensions (LVIDs and LVIDd), fractional shortening (FS), and mitral E-point to septal separation on ultrasonography were assessed at 10 min and at preligation and at 1, 2, and 4 weeks following ligation. The B75 group showed higher mortality (46.7%) than the T75 and B50 groups. The mean infarct size in the B75 group was 22.55 +/- 5.34% which was significantly larger than in the B50 (13.84 +/- 5.46%) and T75 (12.90 +/- 2.67%) groups (p < 0.001). All 3 groups had significantly greater Q or QS wave amplitudes on ECG at 1, 2, and 4 weeks than at 10 min after ligation. At 1 and 2 weeks after ligation, LVIDd, LVIDs, and FS showed significant dfferences in the B75 group as compared with the other groups. The level of ligation of the LCA for the development of a reliable chronic heart failure model in the rabbit is recommended to be 50% from the apex along the course of the posterolateral division in the bifurcation pattern and 75% from the apex along the course of the lateral division in the trifurcation pattern.