Central nervous system control of food intake and body weight

The capacity to adjust food intake in response to changing energy requirements is essential for survival. Recent progress has provided an insight into the molecular, cellular and behavioural mechanisms that link changes of body fat stores to adaptive adjustments of feeding behaviour. The physiological importance of this homeostatic control system is highlighted by the severe obesity that results from dysfunction of any of several of its key components. This new information provides a biological context within which to consider the global obesity epidemic and identifies numerous potential avenues for therapeutic intervention and future research.     

黄脸油葫芦中枢神经系统的组织解剖学研究

应用解剖镜和光镜观察了黄脸油葫芦(Teleogryllus emma (Ohmachi and Matsuura))中枢神经系统的组织解剖学结构，并对脑和各体神经节的组织学结构进行了比较．结果表明，黄脸油葫芦的中枢神经系统由脑、食道下神经节和腹神经索组成；前、中、后脑分化明显，腹神经索包括三对胸神经节、五对腹神经节及纵贯各神经节的神经索；脑和各体神经节的组织学结构相似，由外向内依次是神经鞘、神经细胞层和髓质层；脑的髓质层复杂，其中含有四种由神经细胞球体和神经纤维束形成的脑体，一对蕈状体、一个脑桥体、一个中央体及一对脑腹体。     

食品挤出机模糊控制系统

针对食品挤出机模糊控制系统进行了较深入的研究。基于模糊控制的基本理论 ,阐述了食品挤出机模糊控制器的基本结构及实现方法 ,通过计算机仿真 ,证明了它的优越性     

食品挤出机模糊控制系统

针对食品挤出机模糊控制系统进行了较深入的研究.基于模糊控制的基本理论,阐述了食品挤出机模糊控制器的基本结构及实现方法,通过计算机仿真,证明了它的优越性.     

食品双螺杆挤出机温控系统的模糊免疫PID控制

食品双螺杆挤出机机筒温度对挤压产品产量和质量影响很大,实现对机筒温度的有效控制是一项重要工作.建立控制对象的数学模型,借鉴生物体免疫机理,设计出模糊免疫PID控制器,并进行了仿真研究.结果表明,该温控系统鲁棒性强,响应速度快,动态误差小,性能优于单一的PID控制,能满足食品加工工艺的要求.     

基于室温模糊PID控制的供暖监控系统

基于模糊控制和PID控制理论,在经典PID控制结构中加入Fuzzy自调整结构,对集中供暖系统室温的控制策略进行深入探讨,从而改善室温的自动控制,使系统具有良好的控制效果和鲁棒性。该监控系统以计算机技术、智能仪器仪表技术、传感器技术、现代电子技术和通讯技术相结合,对集中供暖温度监控系统的现场监控软、硬件,及监控中心进行了设计和研究。使该系统实现了远程通讯控制,便于管理,调节直观,可以自动调节室温使其更加舒适,同时提高用户的节能意识,达到良好的节能效果,具有良好的经济效益和社会效益。     

基于组态软件的中央空调监控系统研发

重点阐述了基于组态软件的中央空调系统运行参数实时监测软件平台的开发方法和框架构成.首先从中央空调机组风管系统的特性及监测过程着手,介绍了系统设计的过程,搭建了系统构架;然后设计了基于组态软件组的中央空调机组风管系统自动监测系统,实现了空调机组风管系统自动监测的直观化和数据的动态显示;最后程序调试运行证明系统运行正常,可以实现数据的实时采集、显示和数据库存储等功能,为后期工程应用提供参考.     

Leptin-regulated endocannabinoids are involved in maintaining food intake

Leptin is the primary signal through which the hypothalamus senses nutritional state and modulates food intake and energy balance. Leptin reduces food intake by upregulating anorexigenic (appetite-reducing) neuropeptides, such as alpha-melanocyte-stimulating hormone, and downregulating orexigenic (appetite-stimulating) factors, primarily neuropeptide Y. Genetic defects in anorexigenic signalling, such as mutations in the melanocortin-4 (ref. 5) or leptin receptors, cause obesity. However, alternative orexigenic pathways maintain food intake in mice deficient in neuropeptide Y. CB1 cannabinoid receptors and the endocannabinoids anandamide and 2-arachidonoyl glycerol are present in the hypothalamus, and marijuana and anandamide stimulate food intake. Here we show that following temporary food restriction, CB1 receptor knockout mice eat less than their wild-type littermates, and the CB1 antagonist SR141716A reduces food intake in wild-type but not knockout mice. Furthermore, defective leptin signalling is associated with elevated hypothalamic, but not cerebellar, levels of endocannabinoids in obese db/db and ob/ob mice and Zucker rats. Acute leptin treatment of normal rats and ob/ob mice reduces anandamide and 2-arachidonoyl glycerol in the hypothalamus. These findings indicate that endocannabinoids in the hypothalamus may tonically activate CB1 receptors to maintain food intake and form part of the neural circuitry regulated by leptin.     

Central nervous system and peripheral nerve growth factor provide trophic support critical to mature sensory neuronal survival

Primary sensory neurones in cranial and dorsal root ganglia (DRG) of adult animals are generally thought to be maintained through connections with their peripheral (but not central) targets by trophic factor(s) other than nerve growth factor (NGF). Damage to the peripheral process of sensory neurones results in a dramatic response or even death of the neurones, whereas axotomy (cutting) of the central process does not initiate profound reaction in these neurones. The development and maintenance of neurones are highly dependent on a supply of trophic agents produced by targets and retrogradely transported via the peripheral process to the cell body. NGF deprivation in fetal rodents produced either by exogenously administered antibodies or by those of maternal origin, results in death of DRG and of some cranial sensory neurones. However, as chronic NGF deprivation in neonatal or adult rodents produces little or no cell death, it has been assumed that some other trophic factor(s) derived from the peripheral target sustains sensory neurones in postnatal life. By inducing NGF deprivation by autoimmunizing guinea pigs with mouse NGF and/or by cutting the central root (process) of a DRG, we demonstrate here that under certain conditions DRG neurones require NGF and centrally derived trophic support. Our results indicate that sensory neurones are maintained by the trophic support provided by both peripheral and central targets. This support is mediated by NGF and other as yet unidentified trophic factors. The relative importance of the two target fields and NGF compared with other trophic factors changes during development.     

Caenorhabditis elegans: plague bacteria biofilm blocks food intake

Bubonic plague is transmitted to mammals, including humans, by the bites of fleas whose digestive tracts are blocked by a mass of the bacterium Yersinia pestis. In these fleas, the plague-causing bacteria are surrounded by an extracellular matrix of unknown composition, and the blockage depends on a group of bacterial genes known as the hmsHFRS operon. Here we show that Y. pestis creates an hmsHFRS-dependent extracellular biofilm to inhibit feeding by the nematode Caenorhabditis elegans. Our results suggest that feeding obstruction in fleas is a biofilm-mediated process and that biofilms may be a bacterial defence against predation by invertebrates.     

食品中过敏因素及其风险控制的研究进展

随着科技进步和经济发展,食品安全越来越受到人们的重视,食物过敏这一食源性疾病已引起广大消费者、生产者和研究者的普遍关注。依据近年来有关食品过敏的研究成果,从食物过敏的流行病学、食物过敏因素来源、食物过敏原的检测及食物过敏因素的风险控制等方面综述了食物过敏因素的研究进展。对过敏因素在食品加工处理的稳定性研究,过敏原检测方法,食物过敏与食物过敏研究现状,食物过敏的发病机制等几个方面进行了分析总结,并结合国内外最新的研究成果及颁布的法规,对食物过敏因素的研究工作做出了新的展望,未来食品过敏的研究将从过敏食物或食品的适当标注,开发低敏食品并的建立和使用食物过敏数据库几个方面入手来控制食品过敏因素的风险。     

Apoptosis in the nervous system

Neuronal apoptosis sculpts the developing brain and has a potentially important role in neurodegenerative diseases. The principal molecular components of the apoptosis programme in neurons include Apaf-1 (apoptotic protease-activating factor 1) and proteins of the Bcl-2 and caspase families. Neurotrophins regulate neuronal apoptosis through the action of critical protein kinase cascades, such as the phosphoinositide 3-kinase/Akt and mitogen-activated protein kinase pathways. Similar cell-death-signalling pathways might be activated in neurodegenerative diseases by abnormal protein structures, such as amyloid fibrils in Alzheimer's disease. Elucidation of the cell death machinery in neurons promises to provide multiple points of therapeutic intervention in neurodegenerative diseases.     

Histamine plays a part in induction of drinking by food intake

Drinking occurs around meal time in most mammals. Food-related drinking accounts for approximately 70% of daily fluid intake for rats, but little is known of the mechanisms by which eating elicits drinking. That eating and vagal stimulation elicit the release of histamine from gastric mucosa, together with the fact that drinking elicited by eating or exogenous histamine depends on an intact abdominal vagus, suggests a role for endogenous histamine as a component of food-related drinking in the rat. I report here that the combined antagonism of peripheral H1 and H2 receptors for histamine (1) attenuates drinking elicited by normal food-contingent stimulation of the gastrointestinal tract and (2) abolishes drinking elicited by pregastric food-contingent stimulation during sham feeding in the rat.     

Segmentation in the vertebrate nervous system

Although there is good evidence that growing axons can be guided by specific cues during the development of the vertebrate peripheral nervous system, little is known about the cellular mechanisms involved. We describe here an example where axons make a clear choice between two neighbouring groups of cells. Zinc iodide-osmium tetroxide staining of chick embryos reveals that motor and sensory axons grow from the neural tube region through the anterior (rostral) half of each successive somite. 180 degrees antero-posterior rotation of a portion of the neural tube relative to the somites does not alter this relationship, showing that neural segmentation is not intrinsic to the neural tube. Furthermore, if the somitic mesoderm is rotated 180 degrees about an antero-posterior axis, before somite segmentation, axons grow through the posterior (original anterior) half of each somite. Some difference therefore exists between anterior and posterior cells of the somite, undisturbed by rotation, which determines the position of axon outgrowth. It is widespread among the various vertebrate classes.