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901.
Vascular endothelial cell (VEC) apoptosis is the main event occurring during the development of atherosclerosis. Pterostilbene (PT), a natural dimethylated analog of resveratrol, has been the subject of intense research in cancer and inflammation. However, the protective effects of PT against oxidized low-density lipoprotein (oxLDL)-induced apoptosis in VECs have not been clarified. We investigated the anti-apoptotic effects of PT in vitro and in vivo in mice. PT at 0.1–5 μM possessed antioxidant properties comparable to that of trolox in a cell-free system. Exposure of human umbilical vein VECs (HUVECs) to oxLDL (200 μg/ml) induced cell shrinkage, chromatin condensation, nuclear fragmentation, and cell apoptosis, but PT protected against such injuries. In addition, PT injection strongly decreased the number of TUNEL-positive cells in the endothelium of atherosclerotic plaque from apoE−/− mice. OxLDL increased reactive oxygen species (ROS) levels, NF-κB activation, p53 accumulation, apoptotic protein levels and caspases-9 and -3 activities and decreased mitochondrial membrane potential (MMP) and cytochrome c release in HUVECs. These alterations were attenuated by pretreatment with PT. PT inhibited the expression of lectin-like oxLDL receptor-1 (LOX-1) expression in vitro and in vivo. Cotreatment with PT and siRNA of LOX-1 synergistically reduced oxLDL-induced apoptosis in HUVECs. Overexpression of LOX-1 attenuated the protection by PT and suppressed the effects of PT on oxLDL-induced oxidative stress. PT may protect HUVECs against oxLDL-induced apoptosis by downregulating LOX-1-mediated activation through a pathway involving oxidative stress, p53, mitochondria, cytochrome c and caspase protease. PT might be a potential natural anti-apoptotic agent for the treatment of atherosclerosis.  相似文献   
902.
流动沙丘区和固定沙丘区丘间低地植物种间关联关系   总被引:2,自引:0,他引:2  
丘间低地植物种间关联研究对揭示植物对生境变化的响应及植被演替机制具有重要意义。通过χ2检验和AC关联系数对科尔沁沙地22个不同面积的流动沙丘区和固定沙丘区丘间低地植物种间关联进行了比较分析。结果表明:在固定沙丘区,当丘间低地面积<0.5hm2时,|AC|≤0.3的种对数占所有种对数的百分比和|AC|≥0.7的种对数占所有种对数的百分比略大于流动沙丘区,当丘间低地面积>0.5hm2时,|AC|≤0.3的种对数占所有种对数的百分比显著小于流动沙丘区,|AC|≥0.7的种对数占所有种对数的百分比显著大于流动沙丘区;当面积<0.5hm2时,沙丘固定未引起丘间低地植物种间关系发生明显变化;当面积>0.5hm2时,沙丘固定导致丘间低地植物种间关系更加紧密。  相似文献   
903.
中国沿海代表性河口地区鳗苗群体形态特征的比较研究   总被引:2,自引:0,他引:2  
本文报道了1992—1994年连续3年采自海南至辽宁(包括台湾)沿海7个代表性河口地区鳗苗群体的主要形态特征比较研究结果。4项计数性状和3项度量性状,差异系数分析结果未达到亚种差异水平;判别函数显示,大多数群体间存在显著差异,这种差异应源于遗传变异。各年差异变化无规律,可能与鳗苗漂游分布的随机性有关。  相似文献   
904.
Gibberellins (GAs) are endogenous hormones that play an important role in regulating plant stature by increasing cell division and elongation in stem internodes. The GA2-oxidase gene from Arabidopsis thaliana (AtGA2ox8) was introduced into Brassica napus L. by Agrobacterium-mediated floral-dip transformation with the aim of decreasing the amount of bioactive GA and hence reducing plant stature. As anticipated, the transgenic plants exhibited dwarf phenotype. Compared with the wild type, the transgenic plants had increased primary branches (by 14.1?C15.3%) and siliques (by 10.8?C15.2%), which resulted in a significant increase in the seed yield (by 9.6?C12.4%). Moreover, the contents of anthocyanin in leaves of 60-day-old transgenic plants was about 9.4-fold higher in winter and about 6.8-fold higher in summer than the wild type. These excellent agronomic traits of the transgenic plants could not only improve the lodging resistance and seed yields, but also protect them against stress. Therefore, the over-expression of AtGA2ox8 might be used to produce dwarf varieties and increase seed yield in Brassica napus L.  相似文献   
905.
W Zhuo  L Zhang  B Zhu  J Ling  Z Chen 《PloS one》2012,7(7):e41546

Background

Evidence suggests that MDM2 T309G polymorphism may be a risk factor for several cancers. Increasing investigations have been conducted on the association of MDM2 T309G polymorphisms with lung cancer risk and have yielded conflicting results. Previous meta-analyses on this issue have reported inconclusive data. The aim of the present study was to derive a more precise estimation of the relationship.

Methods and Findings

Updated meta-analyses examining the association between MDM2 T309G polymorphism and lung cancer risk were performed. Separate analyses on ethnicity, smoking status, histological types and gender as well as source of controls were also implemented. Eligible studies were identified for the period up to Feb 2012. Lastly, ten publications including eleven case-control studies were selected for analysis. The overall data failed to indicate a significant association between MDM2 T309G polymorphism and lung cancer risk (GG vs TT OR = 1.14; 95%CI = 0.95−1.37; dominant model: OR = 1.05; 95%CI = 0.92−1.19; recessive model: OR = 1.12; 95%CI = 0.99−1.27). In a subgroup analysis by smoking status, increased lung cancer risk was shown among never-smokers (GG vs TT: OR = 1.76; 95%CI = 1.36−2.29; dominant model: OR = 1.48; 95%CI = 1.22−1.81; recessive model: OR = 1.37; 95%CI = 1.11−1.69). In subgroup analysis by gender, elevated risk was presented among women under a recessive model (OR = 1.29; 95%CI = 1.04−1.59). In the subgroup analysis by ethnicity, histological types and source of controls, no marked associations were observed.

Conclusions

Compared to the previous meta-analyses, the results of this study confirmed that MDM2 T309G polymorphism might be a risk factor for lung cancer among never-smokers. However, the data failed to suggest a marked association between the G allele of MDM2 T309G and lung cancer risk among Asians. More interestingly, subgroup analysis by gender indicated that homozygous GG alleles might raise lung cancer risk among females.  相似文献   
906.
907.
普那霉素是由始旋链霉菌(Streptomyces pristinaespiralis)产生的一类临床上应用的链阳性菌素类抗生素.目前,由于对引起普那霉素产量变化的分子机理知之甚少,从而大大限制了利用分子育种技术来大幅度提高该抗生素产量的研究发展.本研究利用限制性内切酶SacⅡ单酶切处理的扩增片段长度多态性(amplified fragment length polymorphism,AFLP)技术以普那霉素高产重组菌株为材料进行了抗生素高产相关基因的挖掘研究.以原始菌株ATCC25486为对照,筛选出2个仅在高产菌株中特异扩增的多态性DNA片段.进一步的DNA测序分析和同源性比较表明:1个与抗生素生物合成调控基因afsK具有高度的同源性,GenBank收录号为EU123927;另1个是脱氧核糖核酸外切酶编码基因exoSC的同源片段,GenBank收录号为EU123928.因此,这2个DNA片段是与普那霉素产量变化密切相关的新基因,这2个基因的DNA序列的变异应与普那霉素产量的增加密切相关.本研究从普那霉素高产这一生物表型出发,利用分子标记技术筛选出抗生素高产相关新基因,可进一步从基因变异方面揭示了普那霉素高产的分子机理.  相似文献   
908.
This review focuses on four new product categories of food supplements: pre-workout, fat burner/thermogenic, brain/cognitive booster, and hormone/testosterone booster. Many food supplements have been shown to be contaminated with unauthorized substances. In some cases, the ingredients in the new categories of dietary supplements were medicinal products or new synthetic compounds added without performing clinical trials. Some of the new ingredients in dietary supplements are plant materials that are registered in the pharmacopoeia as herbal medicines. In other cases, dietary supplements may contain plant materials that have no history of human use and are often used as materials to ‘camouflage’ stimulants. In the European Union, new ingredients of dietary supplements, according to European Food Safety Authority or unauthorized novel food. Furthermore, selected ingredients in dietary supplements may be prohibited in sports and are recognized as doping agents by World Anti-Doping Agency.  相似文献   
909.

Background

The awareness, treatment and control of diabetes mellitus (DM) can effectively reflect on the social status of diabetes conditions. Although several researchers have investigated the awareness, treatment and control rates of diabetes mellitus in China, little is known about their association with risk factors. This study aims to examine the relationship between risk factors and awareness, treatment and control of diabetes mellitus in northeast China.

Methods

A cross-sectional survey was conducted in 2012. Multistage stratified random cluster sampling design was used to select participants aged 18 to 79 years old. The analysis was based on a representative sample of 1,854 adult subjects. Multivariable logistic regression analysis was used to examine socio-demographic factors associated with the levels of awareness, treatment and control of diabetes mellitus.

Results

The awareness, treatment, and control rates of diabetes mellitus were 64.1%, 52.9% and 44.2%, respectively. In the multivariable logistic regression analysis, family history of diabetes was significantly positively associated with awareness (OR, 2.145; 95% CI, 1.600–2.875) and treatment (OR, 2.021; 95% CI, 1.559–2.619) of diabetes mellitus, while negatively associated with control (OR, 0.671; 95% CI, 0.529–0.951). Cigarette smokers and alcohol drinkers were less likely than non-smokers and non-drinkers to be aware of their blood glucose levels (OR, 0.895, 0.614; 95% CI, 0.659–1.216, 0.446–0.844, respectively). Participants who frequently exercise were more likely to be aware of their diabetic conditions than people who never or rarely exercise (OR, 2.003; 95% CI, 1.513–2.651).

Conclusions

We found that the awareness and treatment of diabetes mellitus were positively associated with age and were high in participants with a family history of diabetes and those who exercise frequently, but low for cigarette smokers and alcohol drinkers. Participants with a family history of diabetes had their diabetic condition poorly controlled.  相似文献   
910.

Background

Fentanyl-induced emesis (FIE) is a distressing adverse effect in the postoperative setting. The genetic basis of FIE remains largely unknown, therefore, we examined whether it was associated with specific genetic variants of OPRM1, the gene encoding the main receptor target of fentanyl.

Methods

In this prospective case-control study, 193 women undergoing gynaecological surgery under a standardized anaesthetic with a low emetogenic risk were enrolled. Inclusion and exclusion criteria were designed to select extreme phenotypes as well as to ensure that most major confounders for FIE were either excluded or present in all patients. To control for unforeseen intra- and postoperative confounders for FIE, only 161 patients were further analysed, out of which 10 were categorized as having FIE, defined by the presence of at least one of three symptoms: nausea, vomiting or retching that was likely to be fentanyl-related. To identify SNPs relevant to FIE in our population, DNA from 40 controls and 10 cases was sequenced at the following OPRM1 regions: 3 kbp of the promoter, main and alternative exons as well as 2 kbp of the 3′ downstream region. The genotype of the significant SNP was further determined in the remaining 111 controls.

Results

The incidence of FIE was 6.2%. Initial sequencing of 10 cases and 40 controls identified 25 SNPs. Only rs540825, a non-synonymous SNP in the splice variant, MOR1X, showed a significant association with FIE post-Bonferroni correction. This SNP was further examined in the remaining 111 controls which confirmed its significant association with FIE (p = 0.019 post-Bonferroni, OR: 5.6, 95% CI: 1.42–21.91).

Conclusions

This is the first report of an association between the occurrence of FIE in Chinese women undergoing gynaecological surgery and an OPRM1 splice variant SNP, rs540825.  相似文献   
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