耗竭-补充营养素对初断乳大鼠进食量及体重的影响

目的：观察锌(Zn)、维生素A(VA)、维生素B2(VB2)缺乏和补充对初断乳大鼠进食量、体重的影响。方法：通过耗竭一补充方式造成初断乳大鼠的Zn、VA、VB2单独和联合缺乏模型，后强化补充相应营养素，动态检测大鼠进食量、体重的变化。结果：Zn、VA、VB2缺乏时不同程度地影响大鼠进食量、体重，以联合缺乏影响最为突出；强化补充相应营养素后，大鼠进食量、体重均得到改善，但仍达不到正常发育水平。结论：婴幼期Zn、VA、VB2缺乏或不足可影响生长发育，应充分重视婴幼儿营养。     

Neuroendocrine factors regulating blood glucose, plasma FFA and insulin in the development of obesity

A number of neurotransmitters and neuropeptides in the hypothalamus play a role in the control of food intake, metabolism, and body weight. Particularly, noradrenergic mechanisms in several areas of the hypothalamus are involved. Control of peripheral metabolism by the hypothalamus is achieved via autonomic modulation of the function of hepatocytes, adipocytes, and the endocrine cells in the islets of Langerhans. The autonomic control mechanisms ultimately lead to an appropriate shaping of blood glucose, plasma FFA, and insulin profiles to guarantee an adequate flow of nutrients under different physiological situations. Peripheral insulin and glucose can penetrate into the brain where they might affect the function of those brain structures involved in control of food intake, metabolism, and body weight.     

市场机制下政府调节与医疗管制制度框架的构建

医疗机构分类管理的政策确定了我国医疗服务的市场取向.我国医疗市场服务因其特殊的技术经济特点也存在一般意义上的市场失灵,使政府管制这一非市场治理机制的产生与存在成为必要,以弥补与矫正市场缺陷,保证医疗服务市场的规范运行和卫生改革的顺利推进.     

Critical trust: understanding lay perceptions of health and safety risk regulation

The binary opposition of trusting or not trusting is inadequate to understand the often ambiguous and contradictory ideas people possess about risk regulators, particularly when knowledge and experience of such institutions is limited. The paper reports qualitative and quantitative data from a major study of public perceptions (n?=?30 focus groups) of UK risk regulators. We compare the complex and widely different ‘trust profiles’ of two regulatory organisations which are institutionally related (the Health and Safety Executive and the Railways Inspectorate) but very separate in the minds of our participants. The paper develops the notion of critical trust to interrogate the various ways in which people make sense of such organisations, as well as discussing the modes of reasoning that people deploy. The paper argues that views of participants are the outcome of a reconciliation of diverse perceptions concerning the role of the organisation, structural factors and the nature of the regulated risk.     

食品添加剂KAl（SO4）2中Al的吸收,排泄,蓄积实验研究

目的：探讨我国主要含铝食品添加剂——硫酸铝钾中铝的吸收、排泄和贮留的基本情况。方法：１．采用６月龄日本雄性大耳兔８只进行３天的代谢平衡实验。２．选用２～３月龄２１只雄性兔进行３２周的蓄积实验。结果：代谢实验表明铝的表观吸收率平均在１０％左右，约９０％的口服铝在粪中排出。尿铝随摄入铝的增加而增加，但肾排铝能力不足吸收的１０％。兔的蓄积实验证明在３２周实验后实验兔随铝摄入的增加其主要脏器均有不同程度的铝蓄积。其蓄积量的顺序为：骨＞肝＞肾＞脑＞心（３．８９～１０５．４６ｍｇ／ｋｇ干重）；蓄积增长倍数为：肝＞脑＞肾＞骨＞心（１．５１～４．５８倍）。结论：１．食品添加剂硫酸铝钾中铝的表观吸收率平均在１０％左右。尿铝随摄入铝的增加而增加，但肾排铝量不足吸收的１０％。２．长期大量摄入含铝食品添加剂可导致机体铝蓄积，其中脑、骨、肝、肾蓄积较明显。     

Brainstem mediates diazepam enhancement of palatability and feeding: microinjections into fourth ventricle versus lateral ventricle

The hypothesis that benzodiazepine-induced hyperphagia is due to a specific enhancement of the palatability of foods has been supported by previous ‘taste reactivity’ studies of affective (hedonic and aversive) reactions to taste palatability. Diazepam and chlordiazepoxide enhance hedonic reactions of rats (rhythmic tongue protrusions, etc.) to sweet tastes in a receptor-specific fashion. A role for brainstem circuits has been indicated by a previous demonstration of the persistence of the taste reactivity enhancement by diazepam after midbrain decerebration. The present study examined whether benzodiazepine brainstem receptors are the chief substrates for palatability enhancement even in intact brains. We compared the effectiveness of benzodiazepine microinjections to elicit feeding and enhance hedonic reactions when delivered into either the lateral ventricle (forebrain) or the fourth ventricle (brainstem) of rats. The results show diazepam is reliably more effective at eliciting feeding and enhancing positive hedonic reactions to oral sucrose when microinjections are made in the fourth ventricle than in the lateral ventricle. We conclude that brainstem neural systems containing benzodiazepine-GABA receptors are likely to be the chief substrates for benzodiazepine-induced palatability enhancement.     

Effects of enteral feedback inhibition on motility,luminal flow,and absorption of nutrients in proximal gut of minipigs

We wanted to clarify whether the postprandial intestinal feedback control activated by nutrients in the distal gut exerts different effects on motility, transit of digesta, and absorption of nutrients in the proximal gut. Additionally, interrelationships among motility, transit, and absorption were to be elucidated because these relationships have only been investigated in the fasted state. In five minipigs, a 150-cm segment of the proximal jejunum was isolated by two cannulas. Motility of the jejunal segment was recorded by multiple strain gauges and analyzed by computerized methods. Markers (Cr- and Cu-EDTA) were used for the measurement of the flow rate, transit time, and absorption of nutrients. After a meal, the test segment was perfused with 2 kcal/min of an elemental diet over a period of 90 min. A feedback inhibition was activated by infusion of nutrients into the midgut at rates of 1–4 kcal/min. Saline was infused as control. With increasing energy loads infused into the midgut, the motility index and the length of contraction waves decreased, whereas the incidence of stationary contractions increased, ie, the motility changed from a propulsive to a segmenting pattern. These modulations of motility were associated with a linear decrease in the flow rate and a linear increase in transit time. Flow and transit were linearly correlated with each other. Additionally, the reduction in flow rate and the delay in luminal transit were associated with a linear increase in the absorption of nutrients. However, the increase in absorption induced by the feedback mechanism was small (7.3–13.4%) compared to the marked inhibition of the motility parameters (54–64%), the flow rate (59%), and the delay of transit (5.8-fold). Feedback control primarily modulated motor patterns and luminal flow, whereas the small increase in absorption was only a side effect due to the longer contact time of the nutrients with the mucosa.The study was supported by the Deutsche Forschungsgemeinschaft, grant Eh 64/6-3.     

Low doses of the 5-HT1A agonist 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH DPAT) increase ethanol intake

Previous work has reported that the 5-hydroxytryptamine (5-HT)_1A agonist, 8-hydroxy 2-(di-n-propylamino)tetralin (8-OH DPAT), reduces ethanol intake by rats. However, as 8-OH DPAT reduces 5-HT neurotransmission, these findings are inconsistent with the proposed inhibitory role of central 5-HT neurons on ethanol intake. We examined the effect of 8-OH DPAT on ethanol, water and food intake in rats maintained on a limited access schedule using a lower dose range (6–250 µg/kg) and by assessing concomitant changes in behaviour. Low doses of 8-OH DPAT enhanced ethanol intake even when food and water were offered as alternatives. Suppression in ethanol intake was observed at higher doses where elements of the 5-HT syndrome were apparent. Similar observations were made in both fluid and non-fluid deprived water drinking rats, suggesting the latter effect is non-selective. Therefore 8-OH DPAT may both increase or decrease ethanol consumption in the rat depending on the dose used.