The Pharmaceutical Journal
Vol 277 No 7431 p747
16 December 2006

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Providing help for victims of dementia more
Mystery of the sinister-looking cherry tree more
How to boost your memory while you are fast asleep more
Did earthly life originate in the ocean's depths? more

Providing help for victims of dementia

Medicines for people suffering from Alzheimer's disease are restricted in accordance with recommendations by the National Institute for Health and Clinical Excellence (NICE), but the decision has been challenged in the High Court. In October NICE ruled that patients with early or late stage Alzheimer’s disease should not be prescribed donepezil, galantamine or rivastigmine, but the drug manufacturers concerned sought a judicial review of the decision on the grounds that NICE had refused to disclose information on the cost effectiveness calculations in detail. The Alzheimer’s Society has welcomed the challenge.

At the same time, joint guidelines aimed at integrating the care of some 700,000 people in England and Wales by the combined health and social care authorities are called for.

At present there is a lack of co-ordination between health and social services professionals, which results in inefficiency, and it is important that the two should work together to remedy the situation. Guidance is required to cover the full range of medical, psychological and social treatments involved. The assessment of memory faculty should be essential for all those individuals with a possible diagnosis of dementia. Age or learning disability should not preclude any of these services and at the same time the carers involved should be offered psychological support from the treatment team.

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Mystery of the sinister-looking cherry tree

The bird cherry (Prunus padus) is a common sight in woodlands, in hedges and beside streams in parts of Britain — from the Welsh marches up into Scotland. In May or thereabouts it flaunts its drooping spikes of white flowers but, with the approach of autumn, it sometimes presents a fantastic sight, appearing almost leafless but heavily festooned with a fine network structure that gives it an arresting and vaguely sinister appearance.

The source of the festoon is the caterpillar of the small ermine moth, which shows a marked preference for the bird cherry. The caterpillars devour the leaves greedily, spinning a communal web to protect themselves against birds and wasps. The tree selected may take on an appearance of lifelessness but it gradually recovers from the onslaught.

Eight species of ermine moth are known to feed on the leaves of just a few trees, although their activity is sporadic and not a regular phenomenon. Closely related moths are to be found now and then feeding on hawthorn and blackthorn growing in a hedge and similarly spinning protective nets. It will be interesting to note what effect, if any, will be produced as our climate changes from year to year.

One intriguing observation is that in the north-east of Scotland the bird cherry was once reputed to be the witches’ tree and it was therefore avoided when a countryman wanted to cut a walking staff from his local hedgerow. The reason for this prohibition is not evident.

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How to boost your memory while you are fast asleep

A commentary in the 9 November issue of Nature offers some fascinating aspects of sleep and its potential for improving memory. One function of sleep may be the consolidation of memories, for it is known that certain tasks learned before a brief nap are better remembered than when there is no interval of this nature.

Researchers at the University of Lübeck have investigated whether oscillations of electrical activity are responsible for the phenomenon rather than levels of brain neuromodulators. They passed a weak electric current to boost brain activity during the phase of deep sleep. Variations of brain currents naturally occur throughout the night, with oscillations becoming fastest during the rapid eye movement phase and slowest during deep sleep. Stimulation of the slow waves appears to be concerned with boosting memory. If a task is learned before sleeping, the brain shows more slow wave activity than during sleep itself.

In the investigation, 13 medical students memorised 46 pairs of words before sleeping. Through electrodes strapped to the scalp, weak current was passed for five periods of five minutes each during the phase of slow wave sleep. The subjects were then allowed to sleep until morning when their word task was repeated.

Control subjects remembered on average 37.4 words before sleeping and recalled 39.5 afterwards. Figures for the treated group — 36.5 and 41.2, respectively — were significantly better. But not all tasks showed such differences. Words and facts were better remembered but a finger-tapping test showed no improvement. It is suggested that intracellular signals in nerve cells are strengthened.

Overnight stimulation might facilitate preparing for examinations, but there is no evidence so far of possible side effects, or whether the effect persists. There might be applications for the treatment of sleep disorders, depression, or even to combat aging. So far, however, there is scant evidence.

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Did earthly life originate in the ocean's depths?

Experts in France and Germany have suggested that earthly life probably originated in the depths of the ocean. A note on this supposition appears in the November issue of Chemistry World. It is argued that the conditions of the earth’s land surface some four billion years ago, when life emerged, would have been distinctly unfavourable to developing organisms. Few modern plant or animal species could survive under the conditions prevalent at that time, when volcanic eruptions and meteorite impacts created an erratic climate above ground. However, the same volcanic activity would have ensured a favourable temperature of 20–50C at the bottom of the oceans. The sea water would have filtered out harmful radiation and the high pressures at depth would have stabilised such essential biological molecules as DNA and RNA.

Most surface organisms can withstand high pressures without detriment to their metabolism or life cycles. It seems probable that a common ancestor of all living organisms was a piezophile, a type of creature that prefers living under high pressures. This raises an intriguing question of the possibility of life today on other celestial bodies such as the deep oceans of Jupiter’s moon Europa, something that would be exceedingly difficult to determine through the procedures currently available to investigators.

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