Heteroepitaxy of Cerium Oxide Thin Films on Cu(111)

An important part of fundamental research in catalysis is based on theoretical and modeling foundations which are closely connected with studies of single-crystalline catalyst surfaces. These so-called model catalysts are often prepared in the form of epitaxial thin films, and characterized using advanced material characterization techniques. This concept provides the fundamental understanding and the knowledge base needed to tailor the design of new heterogeneous catalysts with improved catalytic properties. The present contribution is devoted to development of a model catalyst system of CeO₂ (ceria) on the Cu(111) substrate. We propose ways to experimentally characterize and control important parameters of the model catalyst—the coverage of the ceria layer, the influence of the Cu substrate, and the density of surface defects on ceria, particularly the density of step edges and the density and the ordering of the oxygen vacancies. The large spectrum of controlled parameters makes ceria on Cu(111) an interesting alternative to a more common model system ceria on Ru(0001) that has served numerous catalysis studies, mainly as a support for metal clusters.     

Comparative physiological and proteomic analyses reveal the actions of melatonin in the reduction of oxidative stress in Bermuda grass (Cynodon dactylon (L). Pers.)

The fact of melatonin as an important antioxidant in animals led plant researchers to speculate that melatonin also acts in the similar manner in plants. Although melatonin has significant effects on alleviating stress‐triggered reactive oxygen species (ROS), the involvement of melatonin in direct oxidative stress and the underlying physiological and molecular mechanisms remain unclear in plants. In this study, we found that exogenous melatonin significantly alleviated hydrogen peroxide (H₂O₂)‐modulated plant growth, cell damage, and ROS accumulation in Bermuda grass. Additionally, 76 proteins significantly influenced by melatonin during mock or H₂O₂ treatment were identified by gel‐free proteomics using iTRAQ (isobaric tags for relative and absolute quantitation). Metabolic pathway analysis showed that several pathways were markedly enhanced by melatonin and H₂O₂ treatments, including polyamine metabolism, ribosome pathway, major carbohydrate metabolism, photosynthesis, redox, and amino acid metabolism. Taken together, this study provides more comprehensive insights into the physiological and molecular mechanisms of melatonin in Bermuda grass responses to direct oxidative stress. This may relate to the activation of antioxidants, modulation of metabolic pathways, and extensive proteome reprograming.     

Anti-apoptotic and cytoprotective effect of Enicostemma littorale against oxidative stress in Islets of Langerhans

Context Oxidative stress induces apoptosis within Islets of Langerhans in diabetes mellitus (DM). Enicostemma littorale blume, herb of the Gentianaceae family is used as an anti-diabetic agent across rural India.

Objective This report demonstrates potent anti-apoptotic and cyto-protective activity of Enicostemma littorale MeOH extract (EL MeOH ext.) against 50?μM H₂O₂ in isolated rat Islets.

Materials and methods In this study, the whole plant methanolic extract of EL with doses 0.25–4?mg/mL each for the preincubation duration of 0.5–4?h against 50?μM H₂O₂ were tested for optimum protective dose and time by Trypan blue dye exclusion assay. Islet intracellular reactive oxygen species (ROS) was quantified by DCFDA staining and cell death using PS/PI & FDA/PI staining. Further, comet assay, biochemical assessment of caspase-3 and antioxidant enzyme activities along with immunoblotting of PARP-1, caspase-3, TNF-α activation and p-P38 MapK (stress kinase) induction was performed.

Results The optimized dose of EL MeOH ext. 2?mg/mL for 2?h was used throughout the study, which significantly decreased total Intracellular ROS and cell death. Further, caspase-3 activity, PARP-1 cleavage, p-P38 MapK (stress kinase) activation and TNF-α levels, which had been significantly elevated, were normalized. Antioxidant enzymes like catalase, superoxide dismutase, reduced glutathione and glutathione peroxidase, along with Comet assay, demonstrated that pretreatment with EL MeOH ext. can augment antioxidant enzyme activities and protect from DNA damage.

Discussion and conclusions Significant anti-apoptotic and cyto-protective effects were mediated by EL with Islets of Langerhans subjected to oxidative stress-induced cell death.     

Reduced silent information regulator 1 signaling exacerbates myocardial ischemia–reperfusion injury in type 2 diabetic rats and the protective effect of melatonin

Diabetes mellitus (DM) increases myocardial oxidative stress and endoplasmic reticulum (ER) stress. Melatonin confers cardioprotective effect by suppressing oxidative damage. However, the effect and mechanism of melatonin on myocardial ischemia–reperfusion (MI/R) injury in type 2 diabetic state are still unknown. In this study, we developed high‐fat diet‐fed streptozotocin (HFD‐STZ) rat, a well‐known type 2 diabetic model, to evaluate the effect of melatonin on MI/R injury with a focus on silent information regulator 1 (SIRT1) signaling, oxidative stress, and PERK/eIF2α/ATF4‐mediated ER stress. HFD‐STZ treated rats were exposed to melatonin treatment in the presence or the absence of sirtinol (a SIRT1 inhibitor) and subjected to MI/R surgery. Compared with nondiabetic animals, type 2 diabetic rats exhibited significantly decreased myocardial SIRT1 signaling, increased apoptosis, enhanced oxidative stress, and ER stress. Additionally, further reduced SIRT1 signaling, aggravated oxidative damage, and ER stress were found in diabetic animals subjected to MI/R surgery. Melatonin markedly reduced MI/R injury by improving cardiac functional recovery and decreasing myocardial apoptosis in type 2 diabetic animals. Melatonin treatment up‐regulated SIRT1 expression, reduced oxidative damage, and suppressed PERK/eIF2α/ATF4 signaling. However, these effects were all attenuated by SIRT1 inhibition. Melatonin also protected high glucose/high fat cultured H9C2 cardiomyocytes against simulated ischemia–reperfusion injury‐induced ER stress by activating SIRT1 signaling while SIRT1 siRNA blunted this action. Taken together, our study demonstrates that reduced cardiac SIRT1 signaling in type 2 diabetic state aggravates MI/R injury. Melatonin ameliorates reperfusion‐induced oxidative stress and ER stress via activation of SIRT1 signaling, thus reducing MI/R damage and improving cardiac function.     

Platypnea-Orthodeoxia Syndrome: Diagnostic Challenge and the Importance of Heightened Clinical Suspicion

Platypnea-orthodeoxia syndrome is an uncommon condition of positional dyspnea and hypoxemia; symptoms occur when the patient is upright and resolve with recumbency. Causes can be broadly categorized into 4 groups: intracardiac shunting, pulmonary shunting, ventilation-perfusion mismatch, or a combination of these.Platypnea-orthodeoxia syndrome should be suspected when normal arterial oxygen saturations are recorded while an individual is supine, followed by abrupt declines in those saturations when upright. Further investigations with use of imaging and cardiac catheterization aid in the evaluation. When platypnea-orthodeoxia syndrome is due to intracardiac shunting without pulmonary hypertension, intracardiac shunt closure can be curative.In this article, we report a case of platypnea-orthodeoxia syndrome in an 83-year-old woman who was successfully treated by means of percutaneous transcatheter closure of an atrial septal defect.     

急诊心肌梗死冠状动脉介入治疗术后患者T3水平与心肌再灌注的关系

目的探讨急性心肌梗死（AMI）患者急诊经皮冠状动脉介入治疗（PCI）术后血清三碘甲状腺原氨酸（T3）与心肌再灌注的关系。方法采用化学发光法检测205例AMI患者PCI术后血清T3水平，根据T3水平将患者分为A、B、C、D4组，记录并比较4组患者术后冠状动脉TIMI血流分级、心肌呈色分级（MBG）。结果A组（重度低T3组）TIMI3级比例低于B、C、D组，差异有统计学意义（P＜0.01）；MBG3级比例低于B、C、D组，差异有统计学意义（P＜0.01）。女性患者T3水平（1.00±0.05）nmol/L、TIMI3级比例（32/46，69.6%）、MBG3级比例（24/46，52.2%）均低于男性患者，后者分别为（1.19±0.02）nmol/L、（143/159，89.9%）、（110/159，69.2%），差异均有统计学意义（P＜0.05或0.01）。结论女性AMI患者心肌再灌注水平较男性患者低。AMI患者T3水平与PCI术后冠状动脉再灌注相关，监测T3可以间接反映病情的严重程度。     

2‐deoxy D‐glucose treatment does not elicit a hair growth response in alopecia areata

2‐deoxy D‐glucose (2DG) was tested for efficacy in treating alopecia areata using the C3H/HeJ skin graft model. 2DG has proven to be efficacious in treatment of various mouse models of autoimmunity with minimal serious side effects noted. This agent has been shown to normalize abnormally activated T‐cell populations while also preventing cell surface expression of NKG2D; key factors defining alopecia areata disease progression. Daily oral ingestion of 2DG via drinking water to mice with patchy or diffuse alopecia areata for 16 weeks failed to prevent expansion of alopecia or cause regrowth of hair in treated mice. Histologically, there were no differences between treated and control groups. These results indicate that, while 2DG is effective for some autoimmune diseases, it was not efficacious for the cell‐mediated autoimmune mouse disease, alopecia areata.     

Cardiovascular events associated with nicorandil administration prior to primary percutaneous coronary intervention in patients with acute ST-segment elevated myocardial infarction: a systematic review and meta-analysis

Introduction: Nicorandil may exert cardioprotective effects in ischemic heart disease. However, its efficacy in combination with early reperfusion is uncertain. The authors performed a meta-analysis of the short- and long-term clinical outcomes of nicorandil administration at the time of primary percutaneous coronary intervention (PCI) in patients with ST-elevated myocardial infarction (STEMI).

Methods: PubMed, MEDLINE, Embase, and the Cochrane Library databases were systematically searched for eligible randomized controlled studies. The primary endpoint was major adverse cardiovascular events (MACE), both in-hospital and post-discharge. The secondary endpoint was the incidence of no-reflow phenomenon.

Results: Ten studies were included (n = 1105). Mean patient age was 63.0 ± 10.0 years; 76.6% of patients were male. Compared with controls who received primary PCI, combined nicorandil/primary PCI significantly reduced in-hospital MACE (pooled odds ratio [OR] 0.16; 95% confidence interval [CI] 0.09–0.27), follow-up MACE (pooled OR 0.53; 95% CI 0.37–0.75), and total MACE (pooled OR 0.27; 95% CI 0.15–0.49). The combined treatment also reduced the incidence of no-reflow phenomenon (pooled OR 0.34; 95% CI 0.23–0.50).

Conclusion: Nicorandil administration at the time of primary PCI is associated with reduced MACE (both short- and long-term) and no-reflow phenomenon in patients with STEMI.