白藜芦醇在脑缺血中的神经保护作用

白藜芦醇是存在于多种植物内的一种多酚化合物,具有抗氧化、抗炎、抑制凋亡和清除自由基等作用.白藜芦醇预适应通过激活沉默信息调节因子2同源体1对缺血再灌注大鼠起着神经保护作用,这种作用类似于脑缺血预适应.此外,白藜芦醇还可通过抑制氧自由基和炎性细胞因子生成,缩小脑缺血再灌注小鼠梗死体积和改善神经功能.文章综述了白藜芦醇在脑缺血中的神经保护作用及其机制.     

N‐acetyl cysteine attenuates diazinon exposure‐induced oxidative stress in rat testis

The aim of this study was to investigate the gonadotoxic effects of diazinon and its mechanism of action with special reference to its possible reactive oxygen species generating potential in rat testis and the protective effect of N‐Acetyl Cysteine (NAC) on the exposure of diazinon. The vehicle was given orally to the control group and NAC, diazinon, combination of NAC and diazinon were given to three treatment groups for 4 weeks. Testis lipid peroxidation levels were higher in diazinon group than in control although lipid peroxidation levels were lower in diazinon + NAC group than in diazinon group. The reduced glutathione (GSH) levels were lower in diazinon group than in control and NAC group although its levels were higher in diazinon + NAC group than in diazinon group. Vitamin C, Vitamin E and β‐carotene concentrations were also lower in diazinon group than in control and NAC groups. Vitamin E and β‐carotene concentrations were higher in diazinon + NAC group than diazinon group. Glutathione peroxidase activity and vitamin A concentrations in the testis did not show any difference between the four groups. In conclusion, we observed that NAC treatment modulated diazinon‐induced oxidative injury in the rat testis. These findings suggest that NAC supplementation can be useful in testis oxidative injury caused by the organophosphate insecticides.     

The effects of chronic periodontitis and rheumatoid arthritis on serum and gingival crevicular fluid total antioxidant/oxidant status and oxidative stress index

Background: Chronic periodontitis (CP) and rheumatoid arthritis (RA) appear to share many pathologic features. Oxygen metabolism has an important role in the pathogenesis of both CP and RA. The aim of this study is to evaluate the relationship between these two chronic inflammatory diseases with regard to antioxidant and oxidant status. Methods: A total of 80 participants were divided into four groups of 20 each: group RA–CP (patients with RA and CP), group RA (periodontally healthy patients with RA), group CP (systemically healthy patients with CP), and group C (periodontally and systemically healthy volunteers) were included in the study. After assessment of periodontal measurements, gingival crevicular fluid (GCF) samples were taken at one incisor, premolar, and molar tooth and stored with serum samples at ?80°C for the antioxidant/oxidant assay. Results: Although all clinical measurements in groups RA–CP and CP were statistically higher compared to those of C and RA groups (P <0.001), there were no differences between CP and RA–CP groups (P >0.05). GCF total oxidant status (TOS) values of CP and RA–CP groups were higher than those of the RA group (P <0.05). GCF oxidative stress index (OSI) values of the RA–CP group were higher than those of the RA group (P <0.05). There were no differences among the groups in terms of serum TOS and OSI values (P >0.05). Conclusions: Local OSI values in groups with patients with CP were higher, whereas systemic OSI values showed no difference among the groups. The presence of RA seems not to affect local and systemic OSI values in patients with CP.     

Influence of exposure time to saliva and antioxidant treatment on bond strength to enamel after tooth bleaching: an in situ study

Objectives

This study evaluated the influence of different exposure times to saliva in situ in comparison with an antioxidant treatment on composite resin bond strength to human enamel restored after tooth bleaching.

Material and Methods

Forty human teeth specimens measuring 5x5 mm were prepared and randomly allocated into 5 groups with 8 specimens each: Gct (control group, restored on unbleached enamel); Gbl (restored immediately after bleaching); Gsa (bleached, treated with 10% sodium ascorbate gel for 60 min and restored); G7d (bleached, exposed to saliva in situ for 7 days and restored); and G14d (bleached, exposed to saliva in situ for 14 days and restored). Restored samples were cut into 0.8 mm² sticks that were tested in microtensile. Specimens were microscopically analyzed and failure modes were classified as adhesive, cohesive, or mixed. Pretest and cohesive failures were not considered in the statistical analysis, which was performed with one-way ANOVA and Tukey''s post-hoc test (α=0.05), with the dental specimen considered as the experimental unit.

Results

Mean bond strength results found for Gbl in comparison with Gct indicated that bleaching significantly reduced enamel adhesiveness (P<0.01). However, no statistically significant differences were found between Gct, Gsa and G7d (P>0.05). Bond strength found for G14d was significantly higher than for Gsa (P<0.01). Fractures modes were predominantly of a mixed type.

Conclusions

Bonding strength to bleached enamel was immediately restored with the application of sodium ascorbate and exposure to human saliva in situ for at least 7 days. Best results were obtained with exposure to human saliva in situ for 14 days. Treatment with sodium ascorbate gel for 60 min may be recommended in cases patients cannot wait for at least 7 days for adhesive techniques to be performed.     

The influence of shift work on cognitive functions and oxidative stress

Shift work influences health, performance, activity, and social relationships, and it causes impairment in cognitive functions. In this study, we investigated the effects of shift work on participants' cognitive functions in terms of memory, attention, and learning, and we measured the effects on oxidative stress. Additionally, we investigated whether there were significant relationships between cognitive functions and whole blood oxidant/antioxidant status of participants. A total of 90 health care workers participated in the study, of whom 45 subjects were night-shift workers. Neuropsychological tests were administered to the participants to assess cognitive function, and blood samples were taken to detect total antioxidant capacity and total oxidant status at 08:00. Differences in anxiety, depression, and chronotype characteristics between shift work groups were not significant. Shift workers achieved significantly lower scores on verbal memory, attention–concentration, and the digit span forward sub-scales of the Wechsler Memory Scale-Revised (WMS-R), as well as on the immediate memory and total learning sub-scales of the Auditory Verbal Learning Test (AVLT). Oxidative stress parameters were significantly associated with some types of cognitive function, including attention–concentration, recognition, and long-term memory. These findings suggest that night shift work may result in significantly poorer cognitive performance, particularly working memory.     

Dietary Supplement Use in a Large,Representative Sample of the US Armed Forces

Background

Dietary supplement (DS) use is prevalent among the US Armed Forces personnel, but representative cross-service comparisons and characteristics of personnel using DSs are limited.

内源性抗氧化剂PRDX4及其在生殖系统作用的研究进展

过氧化物还原酶4（PRDX4）是过氧化物还原酶家族成员,是一种细胞内源性抗氧化剂,可锚定在内质网调节蛋白质氧化折叠,也可分泌到细胞外基质发生抗氧化作用。在女（雌）性生殖系统,氧化应激影响卵巢的功能状态,定位在颗粒细胞及卵母细胞的体细胞型PRDX4（PRDX4s）通过抗氧化应激机制促进卵泡发育成熟、抑制卵母细胞老化,并参与多囊卵巢综合征（PCOS）和卵巢功能减退的病理过程。在睾丸组织内同时表达两种PRDX4亚型,PRDX4s和睾丸特异型PRDX4（PRDX4t）。PRDX4通过抑制内质网应激、清除胞质和细胞外基质活性氧簇（ROS）保护睾丸组织结构与细胞功能,参与调节精子发生和精子形成,抑制生精细胞凋亡。综述PRDX4的结构与功能,及其在调节配子发生中的作用。     

排卵后卵母细胞老化的研究进展

卵母细胞老化与许多不良因素有关,氧化应激和线粒体功能紊乱等均致其质量低下,影响进一步发育。作为卵母细胞老化的一种类型,排卵后卵母细胞老化（POA）在体外培养时较为常见,可造成卵母细胞质量下降、胚胎发育不良,导致妊娠率下降和出生缺陷增加。氧化应激是POA过程中的重要触发因素,可激活细胞凋亡通路,影响卵母细胞质量和胚胎发育潜能。现就近年来有关POA的影响因素、与氧化应激的相互作用关系以及使用不同抗氧化剂延缓POA的发生等方面研究进行综述。     

Synthesis,structure, antioxidant activity,and water solubility of trolox ion conjugates

The interaction of trolox with ammonia, alkylamines of different classes, and amino derivatives of heterocyclic compounds, including nitroxyl radicals and alkaloids, led to the production of ammonium salts called ion conjugates (ICs). Five ICs were characterised by X-ray diffraction. This is the first time a wide range of ICs were made from trolox with amines, and ESI-MS data demonstrated they have the potential to generate pseudomolecular [(A^?B⁺)?+?H]⁺ ions. For all obtained trolox ICs, a significant increase (1–3 orders of magnitude) in water solubility was achieved while retaining high antioxidant activity. ICs synthesised from two biologically active fragments may be used to create polyfunctional agents with varying solubility and bioavailability.