A ruling by the European Union heralds the demise of those useful clinical instruments, the mercury thermometer and the mercury sphygmomanometer. The new laws have been passed because of worries about mercury poisoning. Yet you can drink metallic mercury and come to no harm. What does it all mean? There are three forms of mercury from a toxicological point of view: inorganic mercury salts; organic mercury compounds; and metallic mercury. Inorganic mercury salts are water soluble, irritate the gut, and cause severe kidney damage. Organic mercury compounds, which are fat soluble, can cross the blood brain barrier and cause neurological damage. Mercury metal poses two dangers. It can be vaporised: the vapour pressure at room temperature is about 100 times the safe amount, so Keywords: mercury; toxicity; thermometer; sphygmomanometer Toxicity of mercuryA new European Union directive 1 will prohibit the use of mercury in sphygmomanometers and clinical thermometers. We review here the toxic effect of mercury and its compounds and discuss their relevance to the environment and to modern medicine.The Chinese used mercury (II) sulphide 1000 years before the birth of Christ as the red dye pigment vermilion. It was used similarly in the GraecoRoman world, with both Hippocrates and Galen recording its toxic effects. Since then its toxicity has become well known in metalworkers, miners, felthat manufacturers, dyers and paint manufacturers. Despite this, mercury has been incorporated into the treatment of man's maladies from ancient times. Its main use has been to treat syphilis, from its first appearance in the West in the 15th century up to World War II. 2 Mercury and its salts have at various times been used as antiseptics, skin ointments, laxatives, diuretics, bowel washouts for the treatment of colorectal cancer, and scabicides. It is still used today as a solvent for the silver-tin amalgams used in dental fillings. So how toxic is mercury? The hazards of mercuryThere are substantial differences in toxicity of elemental mercury metal, inorganic mercury salts, poisoning can occur if mercury metal is spilled into crevices or cracks in the floorboards. Dentists are occasionally poisoned this way. Mercury easily crosses into the brain, and causes tremor, depression, and behavioural disturbances. A second danger from metallic mercury is that it is biotransformed into organic mercury, by bacteria at the bottom of lakes. This can be passed along the food chain and eventually to man. It was this process that led to the Japanese tragedy at Minimata Bay in the late 1950s when over 800 people were poisoned. It is the need to reduce mercury contamination of the environment which should encourage us to cut the usage of metallic mercury. However, much more metallic mercury is spilled as waste by the chemical industry than is dropped on the floor in the clinic.

High-performance liquid chromatography interfaced with inductively coupled plasma mass spectrometry, and hydride generation-inductively coupled plasma mass spectrometry were used, respectively, to investigate changes in both the chemical form and the concentration of selenium during its bio-incorporation and bio-accumulation into rye seedlings. A 60-fold increase in the total level of selenium in the seedlings ('control' biomass = 0.99 mg kg(-1), 'enriched' biomass = 55.27 mg kg(-1)) was accompanied by a change from selenite to several organo-selenium forms, with more than 40% being present as selenomethionine. The seedling biomass was dried, ground and used as an ingredient in the production of a fermented sourdough bread (popular in Poland and many Eastern European countries). The selenium in the resulting bread was also characterized in terms of its speciation, as well as its total selenium content ('control' bread = 0.06 mg kg(-1), 'enriched' bread = 3.56 mg kg(-1)). The breads were then fed to 24 volunteers as part of a human intervention study designed to establish the efficacy of this mode of selenium supplementation. The human study data subsequently showed the bread was a good source of dietary selenium.

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The octapeptide CF3C02-. + H2-Glu-Ser-Leu-Ser-Ser-Ser-Glu-Glu-OH (1) was synthesized by the Boc-mode of solid-phase peptide synthesis and hydrogenolytic cleavage of the assembled peptide from the resin support. The 13C n.m.r. spectrum of the octapeptide is presented along with its structural analysis by fast-atom bombardment (f.a.b.) mass spectrometry.

use in the development of future therapies aimed at restoring the correct gene expression and thus phenotype in failing cardiomyocytes. M45Diazoxide and ischaemic preconditioning act differently on the mitochondria: is the mitoKATP channel a red herring? KHH Lim, SA Javadov, SJ Clarke, M-S Suleiman, GD Angelini, AP Halestrap.Bristol Heart Institute, Bristol Royal Infirmary, Bristol UK.