The Pharmaceutical Journal
Vol 272 No 7296 p518
24 April 2004

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New light on preserving old oil paintings more
Need for a broader outlook on the nature and purpose of education more
Tackling the tricky problem of antidepressant treatment in childhood more

New light on preserving old oil paintings

An interesting article by Catherine Higgitt of the National Gallery and John Plater of Aberdeen University appears in Chemistry World for April. It discusses the mysterious appearance of tiny white specks and minute patches on the surface of old oil paintings. This offers a challenge to those concerned with the preservation of old masters, since it raises the question whether such inclusions are all part of the painted surface or whether they are a threat to be dealt with.

The National Gallery in London has made a detailed study of paintings ranging from the 13th to the late 18th centuries, including microscopic examinations. It was previously believed that the spotting phenomenon arose from reactions involving the pigment binders, usually linseed or walnut oil with egg-yolk, and now more light has been thrown on the effect.

Drying oils used by painters contain polyunsaturated and saturated fatty acids. Their degradation over time involves cross-linking and oxidation, involving the production of azelaic acid. Infra-red microscopy has shown that the mystery inclusions are of lead compounds, notably basic carbonate and carboxylates, produced by reactions between leaded pigments and acid constituents of the binding oils. Two pigments in particular, red lead and lead-tin yellow, have been widely used and are not confined to any precise historical period.

Under the microscope, the inclusions appear as white opalescent masses within the paint film. The lead-rich areas show a lamellar structure, and are surrounded by patches of lower lead content. The opaque spots are rich in lead carbonates, while the haloes show predominantly lead soaps. In works by Vincent van Gogh in particular, other pigments based on zinc rather than lead produce the same phenomenon.

Despite the ageing of metal carboxylates, the process is a slow one and is self-limiting. When restoration of such pictures is considered, any intervention in these processes is considered undesirable, and they should be left alone.

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Need for a broader outlook on the nature and purpose of education

We hear a great deal about the significance of education and its shortcomings. What we do not hear is any convincing conclusions regarding its essential nature and purpose in civilised communities.

Long ago, in 1850, Herbert Spencer stated: “Education has for its object the formation of character.” And then in 1917 William Ralph Inge commented: “The aim of education is the knowledge not of facts but of values.” These two, the philosopher and the theological dean, therefore seem to be in agreement over the fundamental value of education as a social force. It is to develop the potential of the individual and the individual judgement on the forces shaping the universe.

Today we suffer the inevitable effects of a far narrower view of things. This encourages an outlook based on commercial profit and competitive strife which our political leaders insist should pervade our schools. We are striving for artificial academic distinctions gained by tunnel vision and the exclusion of subjects of study which do not serve that end.

Literature, poetry, music and creative art are really the stuff of civilisation, though they may not bring us more food or smarter machinery or those electronic devices that we find almost impossible to manage without in spite of a sneaking suspicion that they may have adverse effects on our health, physical and mental. Instead, we take the short-term view for the sake of increasing our income and what we fondly imagine is our social status.

It is intriguing to remember that Herbert Spencer, whose education was far from narrow and led him into engineering, teaching and journalism, was an enthusiast over Darwin’s evolutionary theories. He applied them to ethics and sociology and concluded that there was moral justification for the idea of “survival of the fittest”. However, Spencer was also convinced of the power of philosophy to draw together the multitudinous aspects of knowledge and to break down the false isolation of different intellectual disciplines. We would benefit from that attitude today when we look round at our educational system.

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Tackling the tricky problem of antidepressant treatment in childhood

There is a discussion in the 8 April issue of the New England Journal of Medicine concerning the rather tricky problem of antidepressant medication of children, from the US National Institute of Mental Health. In Britain, physicians have been warned to avoid the use of paroxetine generally in treating depressed children younger than 18 years. In the US, the Food and Drug Administration has cautioned that paroxetine therapy should not be discontinued abruptly, from fear of severe withdrawal reactions.

The NEJM article asks whether selective serotonin reuptake inhibitors increase the risk of inducing suicidal behaviour in depressed children. When they were first introduced they were judged superior to earlier antidepressants, being better tolerated and presenting less hazard if taken in overdose. The FDA in the US has given its approval to fluvoxamine, sertraline and fluoxetine for children suffering from major depressive disorders, provided they are older than 8 years. In addition to these, however, paroxetine, citalopram and venlafaxine have been prescribed by US doctors.

Depressed children usually suffer from the sadness, apathy and lack of energy seen in adults, but some manifest only irritability or social isolation syndrome. By their late teens, children aged 10 to 19 who have been treated with antidepressants have shown a higher suicide rate than others. Nevertheless, for obsessive-compulsive disorder, fluvoxamine, sertraline and fluoxetine have proved helpful, although they may induce behavioural abnormalities in some. The efficacy of fluoxetine has been proven in children, and increased suicidal tendencies have rarely been observed. Substantial benefit has also resulted from cognitive-behavioural therapy and similar psychotherapies.

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