Letter
Diamorphine hydrochloride (heroin hydrochloride) is prescribable as a
controlled drug, and is recommended in palliative care for precisely the reasons
that Bolton mentions in his letter.
Although medical supplies of heroin may not end up on the black market its
availability does, unfortunately, lead to occasional abuse by medical
professionals. However, this is true of many drugs, not all of them
controlled.
Tritium file
Some issues raised in your recent article on “hot” seafood and the subsequent
correspondence
(Letters, 14 November, p 58, and 5 December, p 52)
require clarification.
The levels of tritium in flounder caught close to a particular sewer outfall
in the Cardiff area have been measured for many years and have been uniform
throughout that time. The results are held by the Environment Agency and the
Ministry of Agriculture, Fisheries and Food, and are available to the
public.
The maximum radiation dose to humans can be calculated independently of any
models of how tritium behaves in the environment, by using the actual levels
measured in fish.
Consumers of large amounts of local flounder (28 kilograms per year) will
receive about 6 per cent of the relevant dose limit. To put this in perspective,
this is less than the radiation dose received on a flight from London to
Florida, or about 3 per cent of the dose from background radiation.
The regulatory authorities have stated that they believe the tritium levels
in the fish are well within safe limits. The majority of people, naturally, do
not eat this quantity of local flounder and will therefore be exposed to much
lower doses.
Nevertheless, the levels measured in the marine environment are of interest
because of the difference between the measurements and predicted levels. There
are several possible explanations, which are unlikely to relate to an individual
compound or unusual chemistry. We are currently working with a number of
independent groups to study these mechanisms.
The company is also carrying out feasibility studies on technologies that
might reduce the levels of tritium discharged. We hope that these will result in
reductions in the next few years.
The tritium compounds produced at the Cardiff site of Nycomed Amersham are
essential tools in many areas of life science and medical research. They are
vital to our understanding of the molecular mechanisms of disease and the
development of new therapeutic drugs.
Immortal smokers
Death seems to be optional in your 28 November edition.
In the
“Deadly impacts”
table on page 4, the third “deadly impact” seems to
have resulted in no deaths. And on page 18
(“The Chinese way of death”), half
the smokers seem to have found the secret of immortality: “We know that one in
two smokers will die”.
Junk wars
I think I have found an even more satisfying way of dealing with junk mail
than your other correspondents
(Letters, 14 November, p 60).
Admittedly, it doesn’t stem the flow, but it does give you a nice warm feeling.
Simply open the mail and check for a prepaid envelope. If you find one, stuff
it with the contents of some other (preferably unrelated) junk mail and send it
back.
Do not underestimate the therapeutic value of sending a Pavarotti CD offer to
an unsuspecting double glazing company.
Correction
The article on a vaccine against pneumonic plague
(This Week, 5 December, p 4)
mistakenly stated Oya Alpar’s affiliation as the University of Birmingham.
She is in fact based at Aston University in which is in Birmingham.
Silent roads
Matthew Lloyd is not the first to propose “talking tarmac”
(Letters, 5 December, p 54).
At least 15 years ago, the suggestion appeared in the Daedalus
column in New 杏吧原创.
Perhaps the idea was never adopted because people in power would not have
benefited. Their luxury limousines have low-noise tyres and sufficient
sound insulation to prevent the drivers hearing the warnings.
Minds of their own
On a recent visit to London, I was reminded that the trolleys at Heathrow
Airport are possibly the most difficult to control of those of any airport. In a
country otherwise so technologically advanced, it appears that no one is capable
of correcting the flaw in the trolley’s design.
In a supermarket here in South Africa, similar trolleys were used for a few
years. Many shoppers suffered slight to severe back pain, and there were also
numerous embarrassing collisions with these wayward trolleys.
The problem was solved very simply. Heathrow, get your friendly handyman to
weld the rear caster wheels parallel, pointing straight ahead.
Perhaps you could recover the costs of this modification from the original
designer, who should have known that four caster wheels make a trolley
unmanageable.
Not by genes alone
Gail Vines’s nice article on epigenetic effects
(“Hidden inheritance”, 28 November, p 26)
rightly points to imprinted genes as the main
players鈥攁lthough it would be interesting to look at marsupials, where
imprinting supposedly doesn’t occur.
However, there may be other non-genetic factors. For example, a sperm
contributes a structure known as the centriole to the fertilised egg, and this
is now known to be the template for the first cleavage spindle in most mammals
(mice are an exception). In addition, calcium oscillations responsible for
activating the oocyte are triggered by an extranuclear factor or factors from a
sperm’s perinuclear region.
Sperm also carry mitochondria that are normally destroyed but they may
occasionally evade this process鈥攑ossibly by fusing with an egg’s
mitochondria. There are a number of other components such as a unique
alpha-tubulin protein and elements of the tail that could contribute to axis
formation and factors such as nucleo-cytoplasmic ratios in the early embryo.
As human-assisted reproductive technologies are becoming increasingly
intrusive鈥攆or example, attempts to rescue bad eggs by cytoplasmic
transfer鈥攊t is imperative that we come to grips with the biology of what’s
going on. Small babies may foreshadow much nastier anomalies, and we now have
boys being born with the Y chromosome deletions that caused infertility in their
fathers.
We urgently need research in appropriate animal models, particularly
primates. Mice are not especially relevant to human embryogenesis.
Too many meteors
Your article on the Leonid meteors of 1998
(This Week, 28 November, p 20)
perpetuates the claim that observers in the Canary Islands saw up to 2000
meteors per hour.
This widespread myth originated with a professional astronomer who has since
confessed that he did not know the internationally agreed procedure for
reporting meteor rates. Meteor rates are always stated for a single observer,
but the Canary number was the sum of the meteors seen by half a dozen
observers鈥攁nd an extrapolation from only a few minutes of observation.
The analysis of reliable visual observations shows that the meteor rate never
exceeded about 260 per hour anywhere in the world at any time (www.imo.net/news).
At face value, 260 meteors per hour is not much, but
nearly all of them were extremely bright. All the meteor veterans who watched
this extended rain of fireballs agree that it was a unique and stunning
phenomenon. And a good consolation prize for the lack of a distinct meteor storm
the next night.
Backwards advance
There is no need for airlines to install shoulder harnesses and airbags to
save lives in crash landings
(Thistle Diary, 7 November, p 64).
The Royal Air Force and the US Air Force, among others, have increased the chances of their
passengers surviving crashes simply by reversing the seats, so the passengers
fly “backwards”.
Having crossed the Atlantic several times in this manner without discomfort,
I am amazed that civil airlines don’t adopt the same procedure. They may claim
that there is no demand for this, but have passengers been asked?
Cabin crew seats face this way and, given the choice, imagine which way
passengers would prefer to sit when coming in for a crash landing.
Happy with heroin
David Bolton must be confusing Guinness and heroin when he says that he was
able to prescribe the beer but not the drug
(Letters, 5 December, p 52).
Heroin, better known as diamorphine, is available to be prescribed in Britain. In fact,
it must be in the top ten of drugs prescribed on coronary care units.
It is an excellent drug that causes less nausea and low blood pressure than
morphine. It is also easily dissolvable in small amounts, thereby reducing the
volume that needs to be injected. It is an analgesic and anxiolytic (reduces
anxiety), and is therefore used for severe pain in cardiac conditions like
angina and myocardial infarction as well as in palliative care. It can also help
relieve acute left ventricular failure.
Interestingly, alcoholic beverages are also prescribable. The British
National Formulary states that where the therapeutic qualities of alcohol are
required, rectified spirit (suitably flavoured and diluted) should be
prescribed.
However, most hospital pharmacies stock small quantities of unbranded sherry
and whisky. This is usually for long-stay patients or those in terminal care. I
have also seen stout being given out. It has always been small cans of Mackeson,
but I am not sure why.