Goblets of mucus
My only point of contention with your article about the disadvantages of
blowing one’s nose is the comment that “sinuses themselves do not produce mucus”
(9 October, p 25).
The invaginations and extensions of the nasal cavity form the paranasal
sinuses. They are lined by respiratory epithelium similar to that found in the
nasal cavity and the rest of the respiratory tree. Goblet cells in the
respiratory epithelium, together with the submucosal mixed glands, moisten the
epithelial lining of the nose by producing mucus.
Lazy genotype
Your article on the incidence of diabetes in various indigenous populations
mentions the “thrifty genotype” hypothesis
(13 November, p 38).
I was introduced to the issue of the epidemic of diabetes in Papago Indians
through the writings of the ethnobotanist Gary Paul Nabhan. He points out that
in the harsh environment of the Sonoran Desert the people have evolved along
with their food sources. Some of these traditional foods, such as mesquite pod
and seed gums, “may help Indian diabetics to control their health problems, for
when eaten in sufficient quantities, mesquite foods slow down digestion and
reduce radical changes in blood-sugar levels”.
I have also heard that traditional foods of Polynesians may serve a similar
role. When I was an undergraduate at the University of California, Santa Cruz,
one graduate student I knew was studying the cultivation of taro by native
Hawaiians and the important role it played in their diet and in their health,
namely in controlling their diabetes.
In both these communities, people no longer follow their traditional
agriculture and diets, with a corresponding rise in the incidence of
diabetes.
I’m not sure if the relationship between these people and their
traditional鈥攑ossibly blood-sugar modulating鈥攆oods is evidence for
the “thrifty genotype” theory, or if it is support for a third theory. According
to this theory, genetic susceptibility to diabetes in these cultures was able to
develop because their diet controlled blood glucose, so their bodies didn’t need
to. Europeans do not have this genetic predisposition because their diets
selected against that side of the gene pool. I guess this would be more of a
“lazy genotype” theory.
Been there before
I had a distinct sense of d茅j脿 vu on reading the “Opinion”
debate between Mary-Ann McKibben of Alcohol Concern and Jean Coussins of the
Portman Group
(27 November, p 90).
McKibben pursued lines of attack very similar
to those taken by the anti-smoking lobby. In defence, Coussins marshalled many
of the counter-arguments that are so familiar to the tobacco industry.
The common ground discussed by McKibben and Coussins is also shared by the
tobacco manufacturers. We do not target children, nor do we want them to smoke.
Retailers are in the front line of preventing under-age sales and we are
actively supporting them with the CitizenCard proof-of-age scheme.
The ban on tobacco advertising in Europe is not done and dusted. Legal
challenges in the High Court and European Court of Justice are under way. We
fight on to secure the rights of manufacturers to communicate with their
customers and compete for market share for the very same reasons that the
alcoholic drinks sector does.
Clueless Cassandra
The airline passengers’ dilemma when confronted with a card telling them to
call the cabin crew if they can’t read it is not new
(Feedback, 27 November).
Back when the fastest means of international travel was the trireme,
Aeschylus’s Agamemnon related how Clytemnestra told her new slave-girl
Cassandra to make a gesture if she didn’t understand her orders. A joke? A sign
of the queen’s character? Or simply proof that Aeschylus really was drunk when
he wrote his plays?
Diverge and prosper
Yet another article on the ongoing, as yet unanswered, question of species
diversity in the tropics
(20 November, p 47).
Genetic diversity follows a
pattern of increase towards tropical conditions and decrease towards the
poles.
By coincidence, or maybe not, this pattern is also that of sexual
reproduction as opposed to asexual reproduction. Sexual reproduction is, among
other things, a means by which an organism gives itself an advantage in its
struggle with parasitic microorganisms. Tropical environments tend to favour
microorganisms, as anyone who has had to deal with infection in the tropics
knows very well.
It is thought that, in order to reduce this increased likelihood of
infection, rainforest trees spread themselves about among other trees of
different species and, in doing so, favour diversity. An increased diversity of
animal life naturally follows increased diversity of habitat and food
resources.
In any environment that favours infectious microorganisms, any host organism
will, paradoxically, do less well if large numbers live close together. A
species that starts to dominate its environment in this way will put itself at a
disadvantage due to the increased likelihood of infection. Any genetic change
would then be favoured as a way to separate organisms from their own kind, thus
avoiding a dominant monoculture susceptible to attack by a single parasitic
microorganism.
True stories
Your correspondent Keith Franklin asks if the Patent Office assumes
The Beano comic is not fictional
(4 December, p 53).
Recently in
the local branch of a national bookstore I found this year’s The Beano
Annual displayed under the heading “New Non-fiction”. The Patent
Office鈥攁nd the bookseller鈥攎ay know something the rest of us don’t.
Belly-up
Loved your article about fish with “Trojan” genes, with the upside-down photo
of a female medaka fish (Oryzias latipes). Can’t quite see the
relevance to the discussion of larger and more attractive males, but maybe the
message is that in 40 generations the population as a whole goes belly-up.
What not to drink
Your graph of death risk against alcohol consumption
(27 November, p 86)
intrigued me. The graph shows that people who drink no units of wine per day
have a lower risk of death than those who drink no units of beer per day.
When I next go out for a night on the town but need to remain sober, I must
remember that I should not drink wine rather than not drinking beer, thereby
increasing my chances of a long and happy retirement.
Letter
“Who cares?” Hamer asks. Perhaps we all should.
The disappearance of the cork industry would lead to the loss of
traditionally managed habitats in Portugal and Spain鈥攖he wooded
dehesas, and their associated flora and fauna. These areas have a greater
density of songbirds and butterflies than the nearby woods, grasslands and
farmlands. Their survival depends on a market for the produce of the area as
well as on subsidies to help maintain this habitat.
Put a cork in it
Mick Hamer’s interesting article about synthetic corks
(27 November, p 68)
doesn’t mention one culprit, the composition cork, where ground-up corkmeal
mixed with glue is formed into the shape required. When composition cork seals
were introduced鈥攊n the 1960s, as far as I can remember鈥攖hey were apt
to impart a most unpleasant musty taste to a bottle of beer, presumably because
of the binding glue. The problem disappeared when the bare cork surface was
protected by an aluminium or plastic patch.
Wine is sometimes sealed with composition corks, which are never protected by
patches, and I have noticed the same off-flavours with these, although the
causative agent is presumably chemically quite different from the
trichloroanisole which Hamer states is the usual cause of traditional
corkiness.
Contrary to Hamer’s experience, I have encountered “corked” flavours in wines
from screw-top bottles (in sherry, actually). Presumably the mustiness developed
in the vat before the wine was bottled. Such cases can be a bit puzzling,
because only a small part of a bottling run may be affected. The cause is
probably layering in the vat, with only the wine at the surface affected,
because moulds can develop at the wine-air interface.
I think it’s a pity that screw-cap seals seem to have gone out of fashion. I
believe they are ideal, except for high-quality wines, for which good-quality
traditional corks are still the best.
Cheaper in the end
There is nothing more irritating than government health departments whingeing
about how much it will cost to provide the latest medical breakthrough for patients
(20 November, p 18).
Governments put so little money into basic medical research that researchers
are obliged to seek other means of funding the projects that lead to the
breakthroughs. If health departments would only stop complaining for five
seconds, they might realise that if they put their own money into research and
development, the resulting treatments might not cost so much at the end, and the
health departments might share in the profits.
Divine design
I read with interest the review by Lawrence Krauss of Martin Rees’s new book
Just Six Numbers
(4 December, p 48).
Apparently Rees “correctly” and
“quickly” dismisses the “lazy and dishonest claim” that the extraordinary
fine-tuning in our Universe is evidence of “divine design”.
Well, I know that there is such a thing as purposive design because I
experience it in my own consciousness (which philosopher Daniel Dennett has
failed to convince me doesn’t exist). Why, then, is it “intellectually lazy and
dishonest” to ascribe what looks like purposive structure in our Universe to
some kind of parallel cosmic consciousness鈥攁 personal God?
What makes it “reasonable to suspect” that there are an infinite number of
universes which are impossible to visit, and the existence of which we have no
empirical evidence, only a need to explain our own existence without invoking
design?