Impairment of endothelium-dependent arterial relaxation by lysolecithin in modified low-density lipoproteins

Article Abstract:

Atherosclerosis is a condition characterized by changes in the walls of large arteries; these changes can lead to vessel constriction. An aspect of this disease that makes treatment difficult is the unresponsiveness of atherosclerotic arteries to drugs that normally cause vasodilation (opening or widening of the vessel). This lack of response is primarily seen with the type of endothelium-dependent vasodilators (EDVs) that act via receptors on the surface of endothelial cells (the cells that line blood vessels). The response of atherosclerotic blood vessels to EDVs that do not rely on these receptors is essentially normal. Their response to substances that act directly on the smooth muscle component of the arterial wall is also normal. The causes of this selective nonresponsiveness are not known, but it is possible that lipids and lipoproteins (fats and fats bound to proteins) play a role. To determine their importance, the vasodilator responses of normal rabbit aortas (the large artery through which blood leaves the heart to be circulated through the body) were tested before and after incubation (soaking) in various lipids. The researchers used naturally occurring low-density lipoproteins (N-LDL), and LDLs that had been incubated with endothelial cells in tissue culture (EC-LDL). The results demonstrate that a contracted artery did not relax in response to a drug that normally causes relaxation if the vessel had previously been incubated in EC-LDL. N-LDL had no effect. When lysolecithin (a lipoprotein) was substantially removed from EC-LDL by absorption with albumin, EC-LDL interfered much less with vessel relaxation. For all substances tested, the effects on red blood cells were similar to those obtained on endothelial tissue. The results indicate that the lipid attached to the endothelial cell membrane interferes with a regulatory pathway used by several receptor systems. Lysolecithin is known to accumulate in the walls of atherosclerotic arteries and thus appears capable of causing a defect in vasodilation. (Consumer Summary produced by Reliance Medical Information, Inc.)

Case studies, Abnormalities, Atherosclerosis, Lipoproteins, Lecithin, Vascular endothelium

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Collaborations essential for food in the developing world: The stakes in the debate on genetically modified crops increase dramatically as it moves to the developing countries

Article Abstract:

A meeting on agricultural biotechnology in Washington was recently organized by the Consultative Group on International Agricultural Research (CGIAR). The them was ensuring food security, protecting the environment and reducing poverty in developing countries with the help of biotechnology. Transgenic technology has the potential to improve the nutritional value of certain foods, but plant scientists can use many approaches to improve subsistence crops.

Usage, Developing countries, Food and nutrition, Genetically modified plants

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Fatigue, alcohol and performance impairment

Article Abstract:

A study equates the performance impairments due to fatigue with those due to alcohol intoxication. The study involved 40 participants in various sleep and alcohol related experiments. It found that higher levels of impairment occurred with moderate levels of fatigue than the proscribed level of alcohol intoxication, providing a simple index of the relative impairment linked to fatigue.

Drinking of alcoholic beverages, Drinking (Alcoholic beverages), Fatigue

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