Newly discovered endocrine functions of white adipose tissue: possible relevance in obesity-related diseases

During recent years our view of adipose tissue has been revolutionized. White adipose tissue (WAT) is no longer seen as mere energy store or provider of thermal and mechanical insulation. Neglect of WAT has been overcome by surprising discoveries in recent years, changing the view of this tissue towards a highly endocrine organ that is involved in a wide variety of physiological and pathophysiological processes. In this brief article we will focus on new developments in adipocyte and WAT biology. The appreciation of WAT as an endocrine organ will provide the basis for new and promising perspectives in the management of obesity and obesity-related diseases including diabetes, mellitus type II and arterial hypertension.     

Lactoferrin

Mammalian lactoferrin (Lf) receptors are suggested to have pivotal roles for mediating multiple functions of Lf. In this review, we focus on current knowledge of the structure and function of mammalian Lf receptors, mainly the first cloned Lf receptor that has been shown to be expressed in the infant small intestine at high levels but also in virtually all other tissues. The small intestinal Lf receptor takes up iron from Lf into cells and presumably exerts other physiological functions. Other Lf receptors in various tissues have also been reported to mediate some functions of Lf, such as modulating immune function, inhibiting platelet aggregation and enhancing collagen gel contractile strength. The detailed mechanisms behind the receptor-Lf interactions still need to be elucidated.     

Increased mitochondrial palmitoylcarnitine/carnitine countertransport by flavone causes oxidative stress and apoptosis in colon cancer cells

Cancer cell metabolism is characterized by limited oxidative phosphorylation in order to minimize oxidative stress. We have previously shown that the flavonoid flavone in HT-29 colon cancer cells increases the uptake of pyruvate or lactate into mitochondria, which is followed by an increase in O₂^−.. production that finally leads to apoptosis. Similarly, a supply of palmitoylcarnitine in combination with carnitine induces apoptosis in HT-29 cells by increasing the mitochondrial respiration rate. Here we show that flavone-induced apoptosis is increased more than twofold in the presence of palmitoylcarnitine due to increased mitochondrial fatty acid transport and the subsequent metabolic generation of O₂^−. in mitochondria is the initiating factor for the execution of apoptosis. Received 12 August 2005; received after revision 12 October 2005; accepted 14 October 2005     

Compensatory caspase activation in MPP+-induced cell death in dopaminergic neurons

Many have hypothesized that cell death in Parkinsons disease is via apoptosis and, specifically, by the mitochondrial-mediated apoptotic pathway. We tested this hypothesis using a mouse dopaminergic cell line of mesencephalic origin, MN9D, challenged with the Parkinsonism-causing neurotoxin MPP⁺ (1-methyl-4-phenylpyridinium ion). Apoptosis was the main mode of cell death when the cells were subjected to MPP⁺ treatment under serum-free conditions for 24 h. Caspase-3 and caspase-9, however, were not activated, thus indicating the existence of alternate or compensatory cell death pathway(s) in dopaminergic neuronal cells. Using caspase inhibitors, we demonstrated that these pathways involve caspase-2, –8, –6 and –7. A time-course study indicated that activation of caspase-2 and –8 occurred upstream of caspase-6 and caspase-7. Upon MPP⁺ challenge, the apoptosis-inducing factor was translocated from the mitochondria into the MN9D cytosol and nucleus. These results suggest the existence of alternative apoptotic pathways in dopaminergic neurons.Received 20 September 2004; received after revision 5 November 2004; accepted 22 November 2004     

浅谈公路养护管理存在的问题与对策

公路基本建设事业的快速发展,对公路养护工程提出了更高的要求,公路养护不断遇到新的难题,面对困难和挑战。文章结合本地区公路养护实际工作实践,对公路养护管理存在的问题进行了分析,并探讨了相应对策。     

改性海泡石催化剂协同低温等离子体脱除NOx

为了环境保护的目的,采用盐酸浸泡和硝酸铜改性海泡石,并经高温煅烧制得改性海泡石催化剂,在介质阻挡放电反应器中该催化剂协同低温等离子体氧化脱除汽车尾气中的NO.试验证明低温等离子体协同改性海泡石催化剂能够有效脱除NO,反应器输入电压、酸浸浓度以及催化剂煅烧温度对NO脱除率有显著影响.NO脱除率随输入电压增大而增加,等离子体能够有效提高活性粒子和氧自由基浓度,以及增大催化剂的活性和吸附性能.NO脱除率随酸浸浓度和煅烧温度的增大先增加而后降低,NO脱除率具有最佳峰值.最佳实验条件为等离子体输入电压>30 kV、盐酸浓度1.5 mol/L左右、煅烧温度400 ℃左右.NO最大脱除率可达88.4%左右.该研究为脱除NOx的工业性应用提供了理论依据.     

低温等离子体协同絮凝剂净化印染废水

采用针-板式反应器,研究探讨低温等离子体协同絮凝剂处理印染废水色素和COD的影响规律.试验首先探讨了低温等离子放电条件(放电电压、放电时间、放电间距)对印染废水色素和COD处理效果;其次研究在最佳的低温等离子放电条件下,加入絮凝剂对印染废水色素和COD处理的协同作用.结果表明印染废水的脱色率和COD脱除率随输入电压的增大和放电时间的延长而增加;放电介质及放电间距对净化效率也有重要影响,在气相中放电的脱色率优于在液相中放电,COD的脱除率随放电间距的增加而降低.最佳工艺参数为放电电压20kV、放电时间20min、放电间距为阳极在液面以上约12mm,先经过等离子体放电再加入絮凝剂的废水净化效果优于先加絮凝剂再放电的工艺过程.     

用GPS输出反馈实现大角度姿态状态跟踪控制

本文首次讨论并给出了利用星上GPS输出反馈,来实现卫星大角度姿态机动的自主非线性状态跟踪控制系统的设计.其中包括非线性状态反馈控制器的设计以及利用星上GPS伪距测量输出信息,采用修改的罗格里德参数描述姿态状态方程,实现星上实时状态跟踪控制的非线性估计器的设计.文中以EO-1/LandSat7卫星编队飞行为背景,给出了姿态测量信息的获取、姿态状态估计和实时跟踪控制的数学仿真结果,验证了控制系统设计的可行性和正确性,精度指标满足要求.     

冷热交替治疗对肿瘤微循环的损伤及机理研究

肿瘤微循环对肿瘤生长和转移至关重要. 冷热交替治疗已被证实优于以往的单一冷疗或热疗, 其对于肿瘤微循环的损伤程度及机理是肿瘤成功治疗的关键, 但目前该方向的研究甚少. 利用裸鼠脊背皮翼肿瘤视窗模型结合激光共聚焦显微镜技术综合比较了单冷、单热及冷热交替对肿瘤微循环的损伤程度, 并建立了分析肿瘤血管在热物理作用下受力的理论模型, 通过数值计算获得了冷热交替治疗过程中肿瘤微循环血管壁的受力大小. 研究结果发现, 冷热交替造成了肿瘤微循环尤其是肿瘤中央成熟血管严重的结构性损伤. 冷热交替过程中, 血管壁先后受到迅速变化的方向相反的热应力, 有可能在血管壁形成微小裂纹. 随后加热造成的血流快速再灌注对血管壁的作用力存在应力集中现象, 推测血液流动对肿瘤血管壁的快速冲击力很可能是造成血管壁破裂的关键因素, 初步揭示了冷热交替治疗过程中肿瘤血管发生严重损伤的机理.