高等植物中的磷酸烯醇式丙酮酸羧激酶

简要介绍了近年来有关高等植物中磷酸烯醇式丙酮酸羧激酶（ＰＥＰＣＫ）的研究进展,并讨论了此酶的结构、功能和调节等方面的问题。     

Differences in need for antihypertensive drugs among those aware and unaware of their hypertensive status: a cross sectional survey

Peripheral arterial disease (PAD) is a common, progressive manifestation of atherothrombotic vascular disease, which should be managed no different to cardiac disease. Indeed, there is growing evidence that PAD patients are a high risk group, although still relatively under-detected and under treated. This is despite the fact that PAD patients are an increased mortality rate comparable to those with pre-existing or established cardiovascular disease [myocardial infarction, stroke]. With a holistic approach to atherothrombotic vascular disease, our management of PAD can only get better.     

Control of substrate cycling at fructose phosphates in a reconstituted muscle glycolytic system

Using a glycolytic system reconstituted from purified muscle enzymes, it has been demonstrated that addition of fructose bisphosphatase results in a net ATP turnover, indicative of substrate cycling. This occurred in conditions closely simulating those of muscle in the resting state. The cycling depended on the presence of free Mg²⁺ ions; the concentration of free Mg²⁺ in muscle tissue was estimated to be 0.8 mm, and in these conditions the fructose bisphosphatase was approximately 50% active. The effective K_i of fructose bisphosphatase for AMP was estimated to be 1.0 μm, using the equilibrium constants of the creatine kinase and myokinase reactions to calculate AMP concentrations. Neither citrate nor cyclic AMP at physiological concentrations affected substrate cycling significantly.     

The role of discounting and dynamics in determining the economic efficiency of time-area closures for managing fishery bycatch

Time-area closures are commonly used to manage fisheries bycatch and involve temporarily closing an area of the ocean to particular fishing gears. We examine conditions in which implementing a time-area closure would increase the economic value of fisheries, focusing on a case study application in the Gulf of Mexico. Pelagic longline fishermen catch the highly valued Atlantic bluefin tuna (Thunnus thynnus, Scombridae) on their Gulf of Mexico spawning grounds while fishing for Atlantic yellowfin tuna (Thunnus albacares). We analyze a multispecies, multifishery bioeconomic model that includes information on migratory patterns from electronic tagged bluefin tuna. We use dynamic optimization to identify management strategies that would maximize the net present value of tuna fisheries, allowing for discounting of future benefits and costs relative to the present. If past fishing mortality rates continue in Atlantic bluefin tuna fisheries, implementing a time-area closure in the Gulf of Mexico incurs economic costs. However, the net present value of the fisheries is increased by implementing a time-area closure as part of a broader commitment to rebuild the heavily depleted bluefin population, provided the discount rate and the costs of such a closure in forgone fishing opportunities are not too large. The increase in economic value offered by a time-area closure is small relative to the overall economic value of rebuilding itself and it may be economically optimal only to implement a closure once sufficient rebuilding has already taken place.     

Place-Based Attributes Predict Community Membership in a Mobile Phone Communication Network

Social networks can be organized into communities of closely connected nodes, a property known as modularity. Because diseases, information, and behaviors spread faster within communities than between communities, understanding modularity has broad implications for public policy, epidemiology and the social sciences. Explanations for community formation in social networks often incorporate the attributes of individual people, such as gender, ethnicity or shared activities. High modularity is also a property of large-scale social networks, where each node represents a population of individuals at a location, such as call flow between mobile phone towers. However, whether or not place-based attributes, including land cover and economic activity, can predict community membership for network nodes in large-scale networks remains unknown. We describe the pattern of modularity in a mobile phone communication network in the Dominican Republic, and use a linear discriminant analysis (LDA) to determine whether geographic context can explain community membership. Our results demonstrate that place-based attributes, including sugar cane production, urbanization, distance to the nearest airport, and wealth, correctly predicted community membership for over 70% of mobile phone towers. We observed a strongly positive correlation (r = 0.97) between the modularity score and the predictive ability of the LDA, suggesting that place-based attributes can accurately represent the processes driving modularity. In the absence of social network data, the methods we present can be used to predict community membership over large scales using solely place-based attributes.     

Revascularization in the acute coronary syndromes

Coronary heart disease is the leading cause of death worldwide, and occurs when the coronary arteries are unable to supply adequate oxygenated blood to the myocardium, which in turn can lead to ischemia and infarction of myocardial tissue. There are three options for revascularization in the setting of acute coronary syndromes. In select patients, coronary artery bypass surgery remains an option. Thrombolytics were initially the mainstay of therapy, which has now shifted to angioplasty, with or without stents, when readily available. Revascularization has been demonstrated to improve patient outcomes, and has evolved rapidly in the recent past.     

Lipoprotein lipase activator ameliorates the severity of dietary steatohepatitis

Dietary model of steatohepatitis was established by feeding mice a methionine choline deficient (MCD) diet. Mice on MCD or control diet for 3 weeks were treated with or without NO-1886, a newly synthetic lipoprotein lipase (LPL) activator. In a separate experiment, NO-1886 was given after pre-treatment with 3 weeks of MCD diet. NO-1886 significantly reduced MCD-induced inflammation by repressing levels of hepatic lipid peroxides and pro-inflammatory tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and cyclooxygenase-2 (COX-2). In addition, NO-1886 dampened hepatic steatosis via accelerating fatty acid oxidation caused by enhanced expression of PPARalpha, cytochrome P450-10 (Cyp4a10), and Acyl-CoA oxidase (ACO). It failed to regulate genes of fatty acid uptake and synthesis pathways. In conclusion, NO-1886 ameliorated and induced regression of experimental steatohepatitis via increasing endogenous LPL activation resulting in suppression on pro-inflammatory factors and reduction of hepatic fatty acids. These findings indicate that NO-1886 is a potential therapeutic agent for steatohepatitis.     

Access to catheterisation facilities in patients admitted with acute coronary syndrome: multinational registry study

Objective To investigate the relation between access to a cardiac catheterisation laboratory and clinical outcomes in patients admitted to hospital with suspected acute coronary syndrome.Design Prospective, multinational, observational registry.Setting Patients enrolled in 106 hospitals in 14 countries between April 1999 and March 2003.Participants 28 825 patients aged ≥ 18 years.Main outcome measures Use of percutaneous coronary intervention or coronary artery bypass graft surgery, death, infarction after discharge, stroke, or major bleeding.Results Most patients (77%) across all regions (United States, Europe, Argentina and Brazil, Australia, New Zealand, and Canada) were admitted to hospitals with catheterisation facilities. As expected, the availability of a catheterisation laboratory was associated with more frequent use of percutaneous coronary intervention (41% v 3.9%, P < 0.001) and coronary artery bypass graft (7.1% v 0.7%, P < 0.001). After adjustment for baseline characteristics, medical history, and geographical region there were no significant differences in the risk of early death between patients in hospitals with or without catheterisation facilities (odds ratio 1.13, 95% confidence interval 0.98 to 1.30, for death in hospital; hazard ratio 1.05, 0.93 to 1.18, for death at 30 days). The risk of death at six months was significantly higher in patients first admitted to hospitals with catheterisation facilities (hazard ratio 1.14, 1.03 to 1.26), as was the risk of bleeding complications in hospital (odds ratio 1.94, 1.57 to 2.39) and stroke (odds ratio 1.53, 1.10 to 2.14).Conclusions These findings support the current strategy of directing patients with suspected acute coronary syndrome to the nearest hospital with acute care facilities, irrespective of the availability of a catheterisation laboratory, and argue against early routine transfer of these patients to tertiary care hospitals with interventional facilities.