MiR-421 inhibition protects H9c2 cells against hypoxia/reoxygenation-induced oxidative stress and apoptosis by targeting Sirt3.

BACKGROUND: MicroRNAs (miRNAs) are involved in myocardial ischemia-reperfusion injury. miRNA-421 (miR-421) plays a significant role in the initiation of apoptosis and myocardial infarction. However, the molecular regulation of miR-421 in myocardial ischemia-reperfusion injury requires further elucidation. METHODS: An in vitro hypoxia/reoxygenation model was established, and the expression levels of miR-421 and Sirtuin-3 (Sirt3) in H9c2 cells were quantified using quantitative real-time polymerase chain reaction. Flow cytometry was employed to measure the effects of miR-421 on myocardial apoptosis induced by hypoxia/reoxygenation. The activity of lactate dehydrogenase and superoxide dismutase and levels of malondialdehyde were measured. The binding sites of miR-421 on Sirt3 were predicted using TargetScan software. A luciferase reporter assay was used to validate the direct targeting of Sirt3 with miR-421. Protein expression levels of Sirt3 and its downstream proteins were evaluated using Western blot analysis. RESULTS: Exposure of H9c2 cells to hypoxia/reoxygenation led to increased apoptosis, levels of malondialdehyde and lactate dehydrogenase, and decreased levels of superoxide dismutase. miR-421 knockdown resulted in decreased apoptosis, levels of lactate dehydrogenase and malondialdehyde, and increased superoxide dismutase levels in H9c2 cells. Hypoxia/reoxygenation significantly decreased the relative expression levels of Sirt3. Down-regulation of Sirt3 resulted from overexpression of miR-421, which directly targeted Sirt3. Knockdown of miR-421 up-regulated Sirt3 expression, inhibited activation of the Jun N-terminal kinase/activator protein 1 pathway and caspase 9/3-dependent cell death. CONCLUSION: The miR-421-Sirt3-Jun N-terminal kinase/activator protein 1 axis is a novel molecular mechanism that accommodates hypoxia/reoxygenation-induced oxidative stress and apoptosis and provides a new direction for the study and treatment of hypoxia/reoxygenation.

A mixture of carcinoid tumors, extensive neuroendocrine proliferation, and multiple pulmonary sclerosing hemangiomas.

We encountered an extremely rare case of multiple pulmonary sclerosing hemangiomas (PSH) with extensive neuroendocrine lesions, including pulmonary neuroendocrine cell (PNC) hyperplasia, multiple carcinoid tumorlets and typical carcinoid tumors within one pulmonary lobe. To the best of our knowledge, this is the first reported case in the English medical literature of PSH combined and admixed with carcinoid tumors and extensive neuroendocrine proliferation. This case is noteworthy for several reasons. First, the lesion is multi-nodular and unusually large for a typical PSH, which may mimic malignancy on imaging studies and cause diagnostic difficulties. Second, sampling bias may lead to diagnostic errors for a lesion containing two different types of neoplasms. Third, our case displays a rare mixed and mosaic pattern of PSH with a full spectrum of pulmonary neuroendocrine lesions, which may imply a potential intrinsic association in pathogenesis between PSH and concomitant neuroendocrine neoplasms. The clinical implication of multiple PSHs is also discussed.

"Hybrid" approach for the treatment of aortic arch aneurysm.

BACKGROUND: High mortality and morbidity rates are associated with the conventional surgery for aortic arch aneurysm because of cardiopulmonary bypass and deep hypothermic circulatory arrest. In this report, we describe a "hybrid" treatment for aortic arch aneurysm that combines the surgical debranching procedure and the stenting technique. METHODS: A surgical bypass graft is created from the ascending aorta to every main branch of the aortic arch. Subsequently, an endovascular stent graft is deployed retrogradely through the femoral artery with the aid of digital subtraction angiography. RESULT: The patient was discharged on postoperative day 7. A computed tomography scan was routinely performed at 1 week postoperatively to confirm the good patency of all grafts and the stent. CONCLUSION: The feasibility and the benefit of the hybrid treatment for aortic arch aneurysm are confirmed.

[Mental workload for mental arithmetic on visual display terminal].

OBJECTIVE: To investigate the possibility of subjective rate, primary task evaluation and psychophysiology evaluation as methods for mental workload assessment of mental arithmetic on visual display terminal (VDT). METHODS: The indexes including Cooper-Harper scale score, correct rate, speed in answering questions, heart rate variability, pupil size and blink rate were recorded during the performance of three different difficult tasks. RESULTS: With the variable number of formula increasing, the Cooper-Harper scale score increased, the right rate decreased, the speed decreased, pupil size increased, and blink rate significantly decreased. In comparison with rest, the value of TP, VLF, LF, LFnorm, LF/HF decreased remarkably in the mental arithmetic task, the value of HFnorm, HF/TP, rMSSD increased. However, the difference was not significant among three groups. CONCLUSION: With the variable number of formula increasing, the participant's mental workload increases. Every method of mental workload evaluation can assess the mental workload information for three tasks at various different levels in a way. Multi-indexes may be appropriate for mental load assessment.

Expression and significance of cyclin D1, p27kip1 protein in bronchioloalveolar carcinoma.

PURPOSE: To investigate the relationship between expression of cell cycle-related protein cyclin D1, p27kip1 and the pathogenesis of bronchioloalveolar carcinoma (BAC) and the value of prediction of prognosis. METHODS: Cyclin D1 and p27kip1 protein were detected by immunohistochemical En Vision method in 43 BACs. RESULTS: The positivity of cyclin D1 in BAC was 65.1% (28/43), which was significantly higher than that in normal pulmonary tissue (0/13), P<0.01. No statistically significant association was found between cyclin D1 expression data and sex, age, tobacco-use history, histologic subtype (mucinous vs nonmucinous), stromal fibrosis, lymph node metastasis, clinical stage or postoperative survival period (P>0.05), while cyclin D1 expression was found to be negatively correlated with tumor size (P<0.05). The positivity of p27kip1 in BACs was 51.2% (22/43), significantly lower than that in normal pulmonary tissue (12/13), P<0.01. p27kip1 expression level was not associated with sex, age, tobacco-use history, tumor size or histologic subtype (P>0.05), but was negatively correlated with stromal fibrosis, lymph node metastasis and clinical stage (P<0.05); and positively associated with postoperative survival period (P<0.01). The survival rate of p27kip1 positive group was significantly higher than that of p27kip1 negative group (P<0.01). No statistically significant correlation was found between cyclin D1 and p27kip1 expression. CONCLUSIONS: Increased cyclin D1 expression and decreased p27kip1 expression are related to the pathogenesis of BAC; decreased p27kip1 expression is associated with metastasis progression; immunodetection of p27kip1 is useful for assessment of prognosis.

Effect of Salts on the Formation of C(8)-Lecithin Micelles in Aqueous Solution.

The effect of divalent and trivalent salts (CaCl(2), CaBr(2), MgCl(2), MgBr(2), LaCl(3), CeCl(3), La(NO(3))(3), and Ce(NO(3))(3)) on the micelle formation in C(8)-lecithin solutions was investigated using the techniques of static and dynamic light scattering. The critical micelle concentration (cmc), mean hydrodynamic radius (R(h)), gyration radius (R(g)), and weight-average molecular weight of the micelles were measured as functions of salt identity and concentration, amphiphile concentration, and temperature. It was found that the micelles in solutions of magnesium are less likely to form and less stable; their standard enthalpy is less exothermic as the ionic strength increases. On the contrary, the micelles in solutions of calcium and trivalent salts form easily, and are more stable; their standard enthalpy is also more exothermic as the ionic strength increases. Based on our model of the Gibb's free energy for the salt-added solutions, we obtained the following formula for the effect of salts on cmc: ln(cmc)'=ln(cmc)+k(1) I(1/2)+k(2)I, where (cmc)' and (cmc) are the critical micelle concentrations in salt-added and salt-free solutions, respectively, I is the ionic strength, and k(1) and k(2) are the salt effect parameters. The agreement between the formula and the experimental data for all the systems under study shows that the formula is more satisfactory than those suggested previously by other authors in describing the effect of salts on the cmc in the micellar solutions of not only zwitterionic but also nonionic surfactants. Copyright 2001 Academic Press.