Ecstacy and Prozac
We read with interest Peter Aldhous’s topical article on the toxic effects of Ecstasy (New 杏吧原创, Science, 2 September). A new twist in the tale is that some Ecstasy (MDMA) users are combining the drug with Prozac, and in doing so may be reducing its toxicity.
In the laboratory, serotonin re-uptake inhibitors block MDMA-induced serotonin release and they also block MDMA neurotoxicity. It has been reported that fluoxetine (Prozac), a selective serotonin re-uptake inhibitar antidepressant, does not block MDMA’s subjective effect and that MDMA’s psychoactive effects may be separate from its neurotoxic action.
Recently it has come to our notice that antidepressants, particularly fluoxetine, are being used as recreational drugs. Reports from some of our patients suggest that fluoxetine, combined with MDMA, is becoming popular with people who go to metropolitan clubs and raves.
We are told good quality MDMA is becoming hard to find, and so users are resorting to drug combinations to enhance its effects, such as MDMA combined with ketamine, an anaesthetic, and with fluaxetine. According to users, the effects of MDMA last approximately two hours, but when combined with fluoxetine the effects are prolonged by a further two hours. Other stated reasons are the easier “come down” following a high and the absence of hangover effects with fluoxetine.
We are concerned that fluoxetine, which is a prescription only medication, has gained “street value” and is being misused, even if it is incidentally mitigating the toxic effects of MDMA.
Chemical feminism?
I read with interest the article by Gail Vines on the endocrine-disrupting effects of chemicals in our environment that mimic hormones (“Some of our sperm are missing”, 26 August). In that article, John Sumpter says that “fifty years of research are needed” to determine the consequences of these chemicals.
Yet this is one predicament we cannot afford to wait and see for fifty years. Some well-designed epidemiology studies will help unravel the effects. These will need to show: biological credibility (already obvious), dose-response relationship, plausible time between cause and effect, strength of association, and consistency with other findings. It is prudent to act when the bulk of this evidence points to these chemicals as a culprit.
One more possible link, I suggest, comes from observing the previous fifty years of evidence. In the article, Valerie Beral, director of the Imperial Cancer Research Fund’s Cancer Epidemiology Unit in Oxford, states that higher breast cancer rates are probably blamed on the increasing trend for women to have fewer children later in life. There is indeed an association between the age at which a woman has her first child and breast cancer, but has anyone ever considered that the behaviours resulting in “having fewer children later in life” may themselves be a product of hormonal disruption?
Feminist attitudes 鈥� in males and females 鈥� would underlie such behaviour, and the prevalence of feminism has roughly paralleled the widespread use of endocrine-mimicking chemicals. Sex hormones are known to give us our primary and secondary sexual characteristics; attitudes toward sex and reproduction can be thought of as “tertiary” ones.
Of course, there is a cultural mechanism at work behind feminism too, but it is shocking to think that personal attitudes and lifestyles may be heavily influenced by chemicals in our environment.
Face up to malaria
Malaria has not been defeated by chemistry, and it will not be defeated by genetic technology (“Mosquitos that kill malaria”, 5 August). One application of genetics described by your article involves the insertion of mouse genes into the mosquito genome. The murine genes code for antibodies that can recognise and disable the Plasmodium parasite. Because the interaction depends on the ability of the antibodies to recognise specific surface proteins, this approach will not work.
The spread of malaria cannot be stopped by chemistry because the parasites become drug resistant more rapidly than new drugs can be developed. In the genetic approach, the forces of evolution will still result in resistant parasites. Mutant parasites with novel surface proteins will not be recognised by the antibodies. They will survive and multiply and initiate the next attack of malaria. Genetics will not be able to keep up with the evolution of the parasite.
In addition, the parasite is difficult for the human immune system to attack because the surface proteins of Plasmodium can change. As described in Biology (third edition) by Neil Campbell, the parasite shows the immune system a “face” that it does not recognise. Would not the parasite be able to hide from the mouse antibodies in the same manner?
I believe the genetic approach will fall victim to the same challenges which have defeated other attempts to stop the spread of malaria.
Worms are boring
So now the truth is out: nematodes are the most species diverse forms of animal life, with perhaps as many as 100 million species worldwide (This Week, 16 September).
If this is the case, the previous holders of the title 鈥� the insects 鈥� come a poor second, with between a tenth and a third of that number of species, depending on whose estimates one favours. But before we telegate insects to the ranks of second best, perhaps we should think a little more about the difference between species numbers and species diversity.
Morphologically, nematodes are a notoriously conservative lot 鈥� it might be said that once you have seen one, you have seen them all. Insects, on the other hand, are fantastically varied, with a diversity of form that is unparalleled in the animal world.
Is Rockall mud, with its vast numbers of practically identical nematodes, really richer than a rainforest, with its staggering array of insect life? I’ve yet to inspect the Rockall Trough myself; but I think I can guess the answer.
Shell says it is safe to dump in the Rockall Trough because of low biodiversity. John Lambshead of the Natural History Museum says it is not because of high biodiversity. Shouldn’t these arguments be the other way round?
I always thought it was the low biodiversity environments which were fragile and the high biodiversity ones which were robust. Could any of these 100 million species of nematodes be driven to extinction even if one were to try?
Market success?
Your article on energy use in Britain states that “there is no prospect of stabilising carbon dioxide emissions, which will leave our commitments to the Rio Summit in tatters” (Forum, 9 September). Britain is on target to at least stabilise and probably to reduce its CO2 emissions by 2000 compared to 1990, fully satisfying our Rio commitment.
The article also states that “preserving and improving the environment are two of the more spectacular failures of the market so far”. In fact the above fulfilment of the Rio commitment is due entirely to the liberalisation of the electricity generating market. The changes here are single-handedly delivering savings sufficient to offset the increases in CO2 emissions from all other British sectors, notably transport, to deliver the expected stabilisation of Britain’s total emissions.
Finally, the article states that “another failure of the market mechanism is the lack of advances made in improving energy efficiency”. The electricity industry has, for many years, undertaken a whole range of innovative approaches to promoting energy efficiency and, between 1994 and 1998, will spend 拢100 million on projects to save 6000 gigawatts.
However, unlike electricity generation, the end-use market in electricity (and gas) will not be fully open to competition until 1998, so it is not surprising that the influence of market mechanisms on end-use efficiency is not yet apparent.
Insects carry HIV
Steven Ford writes that no one has yet shown that HIV can be transmitted by a non-human vector (Letters, 9 September).
In an article on AIDS in Africa in 1987, Der Spiegel mentioned inter alia that South African scientists had reported to a congress in Hungary that bedbugs infected with HIV in the laboratory could transmit the virus into culture and that of 50 blood-sucking insect samples sent for testing to Professor Chermann at the Pasteur Institute, all were infected.
The probable role of insect vectors in the African epidemic was discussed by Michael Kock in AIDS vom Molekul Pandemie (Spektrum der Wissenschaft, 1987), the English edition of which was suppressed.
Locking out HIV
I propose that it is possible for the functional HIV integrase dimer to bind DNA on each molecule of the dimer (New 杏吧原创, Science, 2 September). This would allow one dimer of integrase to hold both “loose ends” of the cleaved host DNA and permit the virus DNA to quickly “stitch up” the split, DNA, which is easily located by virtue of being clamped in the enzyme. Alternatively, one unit of the enzyme could position the host DNA while the other holds viral DNA during the integration.
Shockingly direct
My personal experience does not quite conform to J. A. Terry’s opinion about the relative dangers of DC versus AC (Letters, 16 September).
As a greenhorn engineer, I suffered a stroke from a 110-volt DC line, with the current passing from hand to hand. I felt no pain, but was completely paralysed and could neither break free nor call for help. Fortunately, after a few seconds, someone noticed something strange going on (my unusual silence?) and banged the red knob. Otherwise, I might have been slowly cooked or electrocuted by the failure of some organ (heart? lung?).
In my later career I experienced numerous shocks from 220 to 380-volt AC (50 hertz), but either the jolt itself broke contact or I was able to drop the tool or wire (rather quickly, I may say). There never was anything again like the DC paralysis.
Over 40 years ago, in the course of an informal meeting at Stoke Mandeville Hospital, R. B. Bourdiloon did a rather hair-raising experiment. Using a foot-operated rheostat, he gradually increased the DC passed across his body via his hands dipping into separate salt-water electrodes.
He got to over one amp without ill effect, but mentioned that any interruption at high current would probably have killed him. I do not remember if he produced any evidence supporting this view.
It makes me wonder if there is really any need to “fry” the occupants of the electric chair.
String Theory
A. F. Webb wonders if anyone else has seen a streak of lightning break up into a string of beads (Letters, 16 September). The phenomenon is well catalogued in Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena, a Catolog of Geophysical Anomalies, compiled by William R. Corliss, published and distributed in 1982 by The Sourcebook Project, P.O. Box 107, Glen Arm, MD 21057, US.
Corliss lists 17 reference works and many examples of bead lightning observed in the US and Europe over the past 150 years or so. He writes: “Spherically segmented lightning or bead lightning may result from longitudinal waves set up in an ordinary lightning stroke by some perturbation. The so-called pinch effect, well known from plasma physics, may cause some constrictions in lightning strokes. In the past, observers maintained that the string of glowing beads was formed of burning bits of matter remaining after the lightning stroke.”
There are many interesting and unusual phenomena in this book. Sprites are described under the heading of “Crown Flash”.
Lightning broken into short lengths is often reported, as “chain”, “beaded” or “pearl-necklace” lightning. I don’t know if a mechanism has been proposed for it, but I would like to suggest one on the basis of an observation I made many years ago.
One particularly bright ground stroke appeared as a remarkably regular sinusoid curve, the x-axis roughly vertical, with many, perhaps 30 or 40, cycles between cloud and ground. This faded quite slowly, taking maybe two or three seconds, and the parts nearest the “x-axis” faded first, leaving the curves around the maxima and minima forming a zig-zag dotted line.
Both the original brightness and slow fading suggest this stroke conveyed a heavy and continuing current. I interpret the sinusoid as the perspective view of a helical discharge channel, suggesting electrons spiralling in a magnetic field (but what caused the field?). As this faded, sections at right angles to the line of sight, forming the parts of the curve nearest the “x-axis”, became invisible first, while light from sections along the line of sight, around the maxima and minima, still added up to visibility.
Carping over cod
Your article on Canada’s cod fisheries raises many issues (“The cod that disappeared”, 16 September).
First, for most stocks there is no demonstrable relationship between spawning stock biomass and recruitment. The figure which would show this is not included in your article; those used do not show that “recruitment falls when fishing pressure is intense”. The knock-on effect described has, as far as I know, not been demonstrated.
Recruitment varies in an unpredictable manner. For example, the North Sea stocks of cod, haddock and whiting have been under intense fishing pressure for decades, but in 1962 recruitment to them suddenly increased by a factor of 2.5 to 3 and then returned to “normal” in the mid-1980s.
It is this unpredictable variability of recruitment which enables governments to ignore scientific advice. They can always bank on a year or more of good recruitment to bail them out of an immediate difficulty, which normally it does, although not in the case of Canadian cod.
Secondly, I would agree that total allowable catches are calculated for many stocks in European waters for which the available data preclude the valid use of the models. However, the brief account of Sidney Holt’s model does not suggest that it will produce better results than existing models. All models face the same problem, that the values of none of the parameters is precisely known, including catches. It is not stated whether Holt’s model takes into account interaction between species or not, another major problem in producing realistic models.
Thirdly, assuming that the model does provide sound advice, the real nub is whether governments would be prepared to implement it. The probability of advice being implemented is inversely proportional to the complexity of the models on which it is based. Holt’s model sounds very complex. While better fish stock assessment models may be needed, much would be gained if existing knowledge were applied.
The majority of governments have no whaling fisheries and are under political pressure to ban whaling, but for fish the opposite is true. However, few governments specify their objectives in managing fisheries, which are primarily to keep up employment. In practice, governments do not manage: they regulate as little as possible in order to avoid political problems.
Much of the difficulty stems from the fact that fish stock management is considered synonymous with fishery management. It is not. While stock management is essential to fishery management, the latter also involves political decisions that take into account economic and social considerations.
There are some of us who see the whole matter in a different perspective; not perhaps as a failure of science but a failure of a political persuasion.
Canada has for nearly two decades been in a phase in which it has persuaded itself that centralised planning, too much akin to the Soviet model in many ways, can provide the solution to every problem that bedevils the economy. Tax-and-spend has been the order of the day, until the national debt has become almost unsupportable.
Huge federal bureaucratic empires have grown and these empires have been duplicated by provincial governments, including the Department of Fisheries and Oceans (DFO). The statistic Parkinson would probably use to characterise this case is the number of civil servants per fish; can anyone provide an estimate?
It is somewhat naive to suppose that such vast bureaucracies will seek scientifically objective policies. These organisations seek, first, their own survival, and the evidence is writ large in the history of the cod’s disappearance. Only after every conceivable and perhaps inconceivable reason has been advanced for the disappearance of the fish is it discovered that the DFO got its sums wrong. Cynics among us guessed that a long time ago.
At the purely political level the Canadian electorate guessed this truth in a general way and reacted to it by decimating the Progressive Conservative Party at the last Federal election in Canada.
The simple lesson is that cod survived for generations under laissez faire but could not survive bureaucratic planning. Don’t blame scientific method; the tool is only as good as the practitioners.
Wrong Israel
Hasn’t anyone else picked up on the error by Dereck Johns in his Feedback Summer Competition entry (16 September)?
Abraham’s wife gave birth to Isaac, who in turn sired Jacob and Esau, the former getting the epithet Israel after dreaming that he wrestled with God.
Oh yeah?
In your article on computer hackers (“Catching Kevin and his Friends”, 2 September), Joe Flower quotes William Cheswick of AT&T and his co-author Steven Bellovin as claiming to have “never had an undetected illegal entry through our firewall”. Well, they have.
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Welsh on the Web
Netropolitan’s list of political parties had one important omission (Technology, 23 September). Plaid Cymru’s communication officer had been on the Net for some time. In August, Plaid’s web site was launched at and it includes biographies of the MPs, the history of the party, party news and even a chance to vote on the question of devolution.
Relatively anon'
The “anonymous” author of the limerick about the relativistic Ms Bright (Letters, 26 August) was A. H. Reginald Butler, one of the founding Science Professors at the University of Manitoba and after whom the building in which I work was named. He was an eminent mycologist, whose fungal drawings remain unsurpassed. Originally from Britain, I am told that among his hobbies, as listed in “Who’s Who”, was crossing the Atlantic Ocean.
Lucky day
I feel moved to comment on Frank Ulrich’s article about Friday the 13th (Forum, 16 September). I may be in the minority, but this Friday the 13th is a very good thing, as I enter my fully fledged adult life on it (it’s my 18th birthday). Also, it is our dearly beloved ex-prime minister’s birthday (Maggie) 鈥� maybe a good thing.
My father was born on Friday the 13th, a very good thing (for me) and got his present job on Friday the 13th. However, I feel that I for one will upset Tom Scanlon’s results as my local supermarket is the same as his, but I feel no urge whatsoever to run down to it on my birthday. I don’t intend to get poisoned, either. Never mind, I’m probably just an exception.