The Pharmaceutical Journal
Vol 278 No 7443 p324
17 March 2007

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Mothers' fish consumption helps child development more
Coffee-drinking and the pregnant woman more
Remembering a chemist with many talents more
Dating art by analysis of the pigments used more

Mothers' fish consumption helps child development

Investigators at the University of Rochester in the US have concluded that the consumption of fish by pregnant mothers has beneficial effects on the development of their offspring, according to a comment in the 17 February issue of The Lancet.

The fetal brain grows rapidly in size and complexity during gestation. At birth it weighs some 350g and it triples in size during the first two decades of life. It is about half lipid — mostly polyunsaturated long-chain fatty acids. These have many roles in the central nervous system. For example, they are precursors of prostaglandins and they are incorporated into cell membranes. The developing brain needs, in particular, arachidonic and docosahexaenoic acids, and it requires them in large quantities, particularly of the latter.

Because the body cannot synthesise enough of these amino acids from precursors, they must be included in the diet. Fish and seafood offer large amounts of fatty acids. It has been shown that higher maternal fish consumption results in children showing better neurological function than those whose mothers have eaten little or no fish during pregnancy.

However, one snag is that fish, as well as providing the essential fatty acids, plus iodine, choline and iron, also contains small amounts of methylmercury, which is neurotoxic. The safe lower limit for methylmercury is unknown. An indication of 10 parts per million in maternal hair may suggest a hazard, but this might arise from exposure to seed grain rather than fish. There are suggestions that caution is desirable and regulatory authorities are aware of the dilemma.

It might be harmful rather than helpful if the public starts to believe that fish consumption should be seriously curtailed because of its potential methylmercury content. Consuming essential fatty acids remains an important factor in promoting infant and child health and should be encouraged despite any possible problems that might complicate the issue.

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Coffee-drinking and the pregnant woman

An editorial in the 24 February issue of the BMJ discusses the wisdom of drinking coffee during pregnancy, a practice that many studies have suggested may be unwise. Some indicate that more than modest amounts increase the risk of infertility, birth defects, miscarriages, stillbirth or premature birth, restriction of fetal growth or cot death.

A study in the same journal shows that babies born to mothers who drink moderate amounts of coffee do not weigh less than those of drinkers of decaffeinated coffee in the second half of pregnancy. The alkaloid crosses the placenta easily and the rate of its metabolism declines during pregnancy. Certainly early miscarriage is more common in women who drink substantial quantities of coffee in early pregnancy. The beverage does not make preterm birth or miscarriage more likely, provided it is not taken to excess.

Estimating fetal exposure to caffeine is difficult, since there are many interacting factors. The speed at which the liver eliminates it varies greatly. There are no reliable figures regarding the supposition that a high intake of caffeine increases the chance of stillbirth, however.

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Remembering a chemist with many talents

In the March issue of Chemistry World there is a profile of Marcellin Berthelot, the French chemist, who died 100 years ago on 18 March 1907.

Berthelot was born in Paris on 15 October 1827, the son of a doctor whose patients mainly came from the poorer quarters of the city. At the Collège Henri IV, he became friendly with Ernest Renan, who interested him in philosophy. Berthelot chose science and medicine as study subjects and gained a doctorate in 1854 through the study of glycerine compounds.

He went on to graduate as a pharmacist in 1858 and, in 1859, was appointed professor of organic chemistry at the École Supérieure de Pharmacie. In 1865 he accepted a chair of organic chemistry specially created for him at the Collège de France.

Berthelot made important contributions to organic, inorganic and physical chemistry and to agricultural, physiological and industrial chemistry. In particular, he took an interest in the ancient chemistry writers and assisted archaeologists by applying analytical techniques to the study of antique materials.

He worked on the relation between inorganic and organic compounds. He invented the terms “endothermic” and “exothermic” for reactions involving absorption and emission of heat and was intrigued by explosions, for a time supervising gunpowder production.

He was also interested in public education — more than 50 French schools adopted his name in their title. He held strong ethical convictions and adopted a secular humanistic outlook. He argued that knowledge should be pursued for the common good and not individual profit and looked to science to liberate humanity from the grip of kings and priests.

He nursed his wife Sophie to the last and died of heart failure an hour after her death. They were buried together in the Panthéon.

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Dating art by analysis of the pigments used

The 15 February issue of Nature includes an interesting comment regarding the importance of spectroscopic laser technology in establishing the origin of disputed works of art.

The work in question is the de Brécy Tondo, a painting of the Madonna and Child acquired in 1981 at a country house sale in England. The collector considered that it was painted by the Renaissance artist Raphael, largely because of its striking resemblance to the 16th century Sistine Madonna in a Dresden art gallery, known to be the work of that artist. However, experts at the gallery judged it to be a much later copy.

Those claiming the earlier origin undertook investigations to prove their claim. Three minute pigment samples taken from the work were submitted to Raman spectroscopic analysis and these indicated that the pigments involved were indeed of Renaissance date. One contained massicot, a yellow material known not to be used by artists after 1700. The binding material appeared to be based on starch, which was commonly used in the Renaissance period. The blue of the robes contained turnsole, a medieval dyestuff, while a few patches of Prussian blue were explained as recent touching-up.

Experts therefore consider that the evidence calls for reassessment of the painting as indeed by Raphael — and thus worth millions of pounds.