Kenneth McColl, consultant gastroenterologist at Glasgow’s Western Infirmary,
has studied the effect of the bacterium in people. He says that the organism’s
ability to neutralise acid may be at the root of its ability to cause disease
(Lancet ii, 1989, p 499).

Duodenal ulcers are common. They can be healed initially, but they almost
invariably relapse. Doctors believe that duodenal ulcers arise when the
stomach produces too much gastric acid. Some researchers have suggested
that stress or diet are part of the cause of this increased acid production,
but there is no convincing evidence that they are involved.

In the past decade, a number of clinical trials worldwide have demonstrated
that one important reason why duodenal ulcers return is the bacterium Helicobacter
pylori. This infects the walls of the lower stomach, or antrum. The bacterium
can survive in the stomach despite the fact that the stomach’s acidity kills
all but the toughest micro-organisms. It neutralises the stomach’s acid
by converting urea in gastric juice into alkaline ammonia.

Researchers have found that if H. pylori is put in a solution with a
pH of 3, it dies, but if urea is added the bacterium thrives. This means
that the urea is essential to the bacterium if it is to make ammonia.

The antrum produces the hormone gastrin, which stimulates the stomach
to secrete acid. When the acidity reaches a peak, the cells that produce
gastrin are ‘switched off’. McColl says that by generating ammonia in the
antrum, the bacterium may deceive these gastrin-producing cells into thinking
the stomach is less acidic than it is, so that they go on making gastrin.

McColl and his colleagues were able to treat people with H. pylori by
giving them a cocktail of antibiotics and a bismuth compound. This eradicated
the bacteria. Curiously, bismuth was a part of the treatment doctors used
for stomach complaints at the turn of the century.

The researchers found that without the bacterium, the stomach released
less gastrin following meals and became less acidic. Earlier clinical trials
showed that people given a short-term treatment that killed H. pylori remained
free from duodenal ulcers for long periods. This treatment is more effective
than using drugs that simply stop the acid being produced.

H. pylori may be spread from one person to another by close contact,
according to a recent study from Toronto. Brendan Drumm and his colleagues
at the Hospital for Sick Children of the University of Toronto investigated
the families of children who were suffering from gastritis, an inflammation
of the stomach, caused by the bacteria. They found that the children’s brothers
and sisters were far more likely to harbour the bacterium than other children
chosen at random. So, too, were the children’s mothers – though not their
fathers interestingly. According to Drumm, the clustering of infection within
families suggests that the bacteria spread from one person to another.

Researchers are also focusing on the possibility that H. pylori is a
cause of stomach cancer. ÐÓ°ÉÔ­´´s from the Imperial Cancer Research Fund’s
Cancer Epidemiology Unit in Oxford have compared levels of gastric cancer
with the prevalence of H. pylori infection in different parts of China.
They find that areas with high levels of the disease tend also to have high
levels of the bacterium.

The Oxford epidemiologists say that many factors over several decades
affect the development of stomach tumours, and H. pylori may be one of them.
They have studied people from Caerphilly, in South Wales, a town which has
a high rate of gastric cancer. It also has high levels of H. pylori. The
team found that about half of the elderly population harboured the bacterium,
the great majority without ill effect. But there is a possible role for
H. pylori in causing the cancer, the researchers say.

Doctors know that active gastritis is caused by heliobacter. It leads,
in a small proportion of people, to so-called atrophic gastritis, in which
secreting glands in the stomach wall die off, causing a drop in production
of acid. This allows bacteria which are not usually found in the stomach
to flourish. The researchers believe that certain of these organisms convert
nitrates into nitrites, which can cause cancer. If bacteria damage the layer
of mucus which protects the stomach lining, it may make it easier for all
manner of cancer-causing substances to enter into the stomach.

So H. pylori may be involved in causing more diseases than anyone suspected.
It’s bad news for those who think stress causes ulcers; you might catch
one.

In the new technique, known as rotational angioplasty, the surgeon inserts
a fine catheter into an artery near the patient’s groin. The catheter passes
slowly along blood vessels until it reaches the heart. The surgeon then
steers the catheter tip into the opening of the coronary arteries until
it reaches the obstruction that is cutting off some of the blood supply
to the heart muscle. The drill is then passed along the length of the catheter.

The device consists of a small battery-powered motor which drives a
flexible rotating wire contained in a sheath at speeds of up to 300 revolutions
per minute. At its tip is a polished metal head in the shape of an olive
about 1.5 millimetres in diameter.

The sequence of X-ray images shown above was taken earlier this year
showing the latest of the cases treated in Bristol. The problem was caused
by a complete blockage in the circumflex artery. Only the stump of this
blood vessel is visible (centre top of the first X-ray). To the right of
it the full length of another coronary artery is visible.

The second image, taken minutes later, shows the drill having successfully
made a channel through the blockage in the artery. The drill does not actually
remove any of the deposit but simply pushes a path through it. The surgeon
then withdraws the drill and replaces it with a catheter containing a long,
thin balloon. Inflation of this balloon pushes the artery walls apart. In
the final image, the surgeon has injected a tracer dye into the circumflex
artery to check that it has been fully opened and the flow of blood is restored.

In 30 to 40 per cent of cases, the arteries narrow again within 6 months
so the treatment must be repeated, but the majority of sufferers are free
from symptoms for longer periods.