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Better brain plumbing
Letters– Therapies analysed From Ben Alldred It was interesting to read Darian Leader and David Corfield describing the effects that medical views popular from the 1970s had on training and on the diagnosis of psychosomatic illness (17 February, p 46). I was surprised, though, by their belief that people might need to see a psychoanalyst “three or four times a week over several months or years”. Is it the patient who benefits from this belief about ability to change, or the analyst? Constructivist modes of psychotherapy start from a presupposition that people can change quickly and effortlessly when the correct motivations for
across the medical spectrum be expected to take on board ideas from psychoanalysis when Leader himself apparently fails to recognise the contributions of psychology outside the Freudian tradition? Since the medical profession relies heavily on evidence-based practice, it might even be expected that psychoanalysis is the area of psychology that would appeal least to doctors. It should not take a psychoanalyst to work out what drives – conscious or not – might cause Leader to “repress” the contribution of other psychological research to our understanding of illness. Cambridge, UK
Don’t blame the plague
change are identified. It seems unscientific to suggest that a person can undergo a rapid traumatic change and yet deny that they can change equally rapidly in a developmental way. Warrington, Cheshire, UK From Mary McAuley I was bemused by Leader and Corfield’s proposal that doctors could treat people more effectively “if they opened up to psychoanalytic ideas”. Did any other readers familiar with different psychological approaches – behavioural, cognitive, humanist or evolutionary, to name a few – appreciate the irony of Leader’s conclusion that “all we’re hoping for is a culture in which there is more dialogue between the specialties”? How can busy GPs requiring working knowledge 22 | NewScientist | 10 March 2007
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From Menno Jan Bouma Sharon Moalem hypothesises about plague’s contribution to the persistence and spread of haemochromatosis (17 February, p 42). A more parsimonious hypothesis might be that haemochromatosis was an adaptation to an iron-deficient diet, anaemia being a serious contributory cause of death in the past and present. Perhaps most damning for the plague hypothesis is that one of Moalem’s key arguments – that young males with their higher haemoglobin levels were more susceptible to dying of plague than females, as observed in 17th-century London – cannot be generalised. More recent reliable records from 1908 to 1917 from the Punjab in India show a highly significant 23 per cent excess of female deaths due to plague, averaged over all age groups. Nenagh, Tipperary, Ireland Sharon Moalem replies: ● Bouma’s theory and my own are not mutually exclusive. Haemochromatosis mutations may well have arisen to increase iron uptake, especially in females in regions that have an iron-poor diet. But the C282Y mutation, which results in the most iron
loading, is only found in appreciably high numbers in western Europe, and the H63D variant is considerably more common in western Europe than elsewhere, although iron deficiency is not special to western Europe. The Indian example is flawed, since women there probably had diets extremely poor in iron, resulting in severe anaemia and much greater risk of infections.
epidemiological evidence shows no association between Alzheimer’s disease and previous surgery requiring anaesthesia. If elderly patients put off necessary surgery for fear that the anaesthetic will harm them, they may place themselves at higher risk of disease or death than any small cognitive effect caused by surgery and anaesthesia. Boston, Massachusetts, US
From Jan Meulendijk Reading Sharon Moalem on the potential benefits (at least for some) of bloodletting, one wonders whether that practice found its justification in the iron-lowering effects it has on the subject. Maybe it was not altogether as silly an idea as one might nowadays think. Haverfordwest, Pembrokeshire, UK
Better brain plumbing
Fear of anaesthesia From Gregory Crosby, Deborah Culley and Zhongcong Xie, Harvard Medical School, and Roderic Eckenhoff, University of Pennsylvania School of Medicine In the article “Alzheimer’s alert over anaesthetics” Helen Phillips cites work by Pravat Mandal showing that the inhalational anaesthetics halothane and isoflurane, and the intravenous anaesthetic propofol, “encourage clumping of amyloid beta protein” (28 October 2006, p 12). Indeed they do – in the test tube, using artificially high concentrations of both amyloid beta protein and anaesthetic. This is not novel; it was shown two years before by one of us (Eckenhoff) and co-workers. However, it is the breathtaking leap to clinical relevance that concerns us. You quote Mandal saying “it is a seriously deadly combination when an older person receives halothane”. This is a grossly premature statement that borders on irresponsibility: there are no adequate animal or clinical studies to support it. The available
From John Davies, Royal Lancaster Infirmary The mammalian brain is rather better protected against stroke than shown in the illustration to the article “Back-up circulation kicks in after stroke” (24 February, p 14). The diagram showed the two arteries, carotid and vertebral, that supply each side of the brain, and the Circle of Willis, which connects all four arteries. A blockage at the site shown – in a carotid below the Circle – would have no effect on the brain, as the other three arteries can supply the brain’s needs. What you should have shown were the main branches from the Circle: the anterior, middle and posterior cerebral arteries. Blockage of any these could benefit from the work described. Lancaster, UK
Graphical grief From Francis Massen Your diagram comparing natural solar radiation with man-made effects is misleading and could be seen as dishonest (10 February, p 9). It shows two discs to compare these effects, the larger one having about 13 times the diameter of the smaller one. As you write, the increase in solar radiative forcing is 0.12 watts per square metre, compared to manmade effects accounting for 1.6 W/m2, according to the Intergovernmental Panel on Climate Change: that is, about 13 times as much. But discs are www.newscientist.com
2/3/07 4:34:17 pm
across the medical spectrum be expected to take on board ideas from psychoanalysis when Leader himself apparently fails to recognise the contributions of psychology outside the Freudian tradition? Since the medical profession relies heavily on evidence-based practice, it might even be expected that psychoanalysis is the area of psychology that would appeal least to doctors. It should not take a psychoanalyst to work out what drives – conscious or not – might cause Leader to “repress” the contribution of other psychological research to our understanding of illness. Cambridge, UK
Don’t blame the plague
change are identified. It seems unscientific to suggest that a person can undergo a rapid traumatic change and yet deny that they can change equally rapidly in a developmental way. Warrington, Cheshire, UK From Mary McAuley I was bemused by Leader and Corfield’s proposal that doctors could treat people more effectively “if they opened up to psychoanalytic ideas”. Did any other readers familiar with different psychological approaches – behavioural, cognitive, humanist or evolutionary, to name a few – appreciate the irony of Leader’s conclusion that “all we’re hoping for is a culture in which there is more dialogue between the specialties”? How can busy GPs requiring working knowledge 22 | NewScientist | 10 March 2007
070310_R_Letters.indd 22
From Menno Jan Bouma Sharon Moalem hypothesises about plague’s contribution to the persistence and spread of haemochromatosis (17 February, p 42). A more parsimonious hypothesis might be that haemochromatosis was an adaptation to an iron-deficient diet, anaemia being a serious contributory cause of death in the past and present. Perhaps most damning for the plague hypothesis is that one of Moalem’s key arguments – that young males with their higher haemoglobin levels were more susceptible to dying of plague than females, as observed in 17th-century London – cannot be generalised. More recent reliable records from 1908 to 1917 from the Punjab in India show a highly significant 23 per cent excess of female deaths due to plague, averaged over all age groups. Nenagh, Tipperary, Ireland Sharon Moalem replies: ● Bouma’s theory and my own are not mutually exclusive. Haemochromatosis mutations may well have arisen to increase iron uptake, especially in females in regions that have an iron-poor diet. But the C282Y mutation, which results in the most iron
loading, is only found in appreciably high numbers in western Europe, and the H63D variant is considerably more common in western Europe than elsewhere, although iron deficiency is not special to western Europe. The Indian example is flawed, since women there probably had diets extremely poor in iron, resulting in severe anaemia and much greater risk of infections.
epidemiological evidence shows no association between Alzheimer’s disease and previous surgery requiring anaesthesia. If elderly patients put off necessary surgery for fear that the anaesthetic will harm them, they may place themselves at higher risk of disease or death than any small cognitive effect caused by surgery and anaesthesia. Boston, Massachusetts, US
From Jan Meulendijk Reading Sharon Moalem on the potential benefits (at least for some) of bloodletting, one wonders whether that practice found its justification in the iron-lowering effects it has on the subject. Maybe it was not altogether as silly an idea as one might nowadays think. Haverfordwest, Pembrokeshire, UK
Better brain plumbing
Fear of anaesthesia From Gregory Crosby, Deborah Culley and Zhongcong Xie, Harvard Medical School, and Roderic Eckenhoff, University of Pennsylvania School of Medicine In the article “Alzheimer’s alert over anaesthetics” Helen Phillips cites work by Pravat Mandal showing that the inhalational anaesthetics halothane and isoflurane, and the intravenous anaesthetic propofol, “encourage clumping of amyloid beta protein” (28 October 2006, p 12). Indeed they do – in the test tube, using artificially high concentrations of both amyloid beta protein and anaesthetic. This is not novel; it was shown two years before by one of us (Eckenhoff) and co-workers. However, it is the breathtaking leap to clinical relevance that concerns us. You quote Mandal saying “it is a seriously deadly combination when an older person receives halothane”. This is a grossly premature statement that borders on irresponsibility: there are no adequate animal or clinical studies to support it. The available
From John Davies, Royal Lancaster Infirmary The mammalian brain is rather better protected against stroke than shown in the illustration to the article “Back-up circulation kicks in after stroke” (24 February, p 14). The diagram showed the two arteries, carotid and vertebral, that supply each side of the brain, and the Circle of Willis, which connects all four arteries. A blockage at the site shown – in a carotid below the Circle – would have no effect on the brain, as the other three arteries can supply the brain’s needs. What you should have shown were the main branches from the Circle: the anterior, middle and posterior cerebral arteries. Blockage of any these could benefit from the work described. Lancaster, UK
Graphical grief From Francis Massen Your diagram comparing natural solar radiation with man-made effects is misleading and could be seen as dishonest (10 February, p 9). It shows two discs to compare these effects, the larger one having about 13 times the diameter of the smaller one. As you write, the increase in solar radiative forcing is 0.12 watts per square metre, compared to manmade effects accounting for 1.6 W/m2, according to the Intergovernmental Panel on Climate Change: that is, about 13 times as much. But discs are www.newscientist.com
2/3/07 4:34:17 pm