Control of encrustation and blockage of Foley catheters

D J Stickler, G L Jones, A D Russell

Urinary catheters often become encrusted and blocked by crystalline Proteus mirabilis biofilms. Results of experiments in a laboratory model of a Foley catheterised bladder infected with P mirabilis showed that when retention balloons were inflated with a solution of triclosan (10 g/L), the catheters drained freely for at least 7 days. Triclosan became impregnated throughout the silicone catheter material and completely inhibited the formation of crystalline biofilm, whereas catheters inflated with water became blocked in 24 h. Our observations suggest a way to control a common complication in patients with long-term indwelling bladder catheters.

Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3TL, Wales, UK (D J Stickler DPhil, G L Jones BSc); and Welsh School of Pharmacy, Cardiff University, Cardiff (A D Russell FRCPath)

Nitroprusside in Severe Aortic Stenosis and Heart Failure

In critically ill patients with aortic stenosis and left ventricular dysfunction, vasodilator therapy has been considered to be contraindicated because of concern that it could cause hypotension. In this study, nitroprusside was administered to 25 such patients under carefully monitored conditions and, contrary to traditional teaching, was found to cause substantial improvement in the cardiac index and other hemodynamic variables.

These findings will change the standard approach to the treatment of these severely ill patients. Nitroprusside therapy can be used as a bridge to aortic-valve replacement or to maintenance therapy with oral vasodilators.

Einstein and Newton showed signs of autism

They were certainly geniuses, but did Albert Einstein and Isaac Newton also have autism? According to autism expert Simon Baron-Cohen, they might both have shown many signs of Asperger syndrome, a form of the condition that does not cause learning difficulties.

Although he admits that it is impossible to make a definite diagnosis for someone who is no longer living, Baron-Cohen says he hopes this kind of analysis can shed light on why some people with autism excel in life, while others struggle.

Autism is heritable, and there are clues that the genes for autism are linked to those that confer a talent for grasping complex systems - anything from computer programs to musical techniques. Mathematicians, engineers and physicists, for instance, tend to have a relatively high rate of autism among their relatives.

Baron-Cohen, who is based at Cambridge University, and mathematician Ioan James of Oxford University assessed the personality traits of Newton and Einstein to see if they exhibited three key symptoms of Asperger syndrome: obsessive interests, difficulty in social relationships, and problems communicating.

Newton seems like a classic case. He hardly spoke, was so engrossed in his work that he often forgot to eat, and was lukewarm or bad-tempered with the few friends he had. If no one turned up to his lectures, he gave them anyway, talking to an empty room. He had a nervous breakdown at 50, brought on by depression and paranoia.

Repeated sentences

As a child, Einstein was also a loner, and repeated sentences obsessively until he was seven years old. He became a notoriously confusing lecturer. And despite the fact that he made intimate friends, had numerous affairs and was outspoken on political issues, Baron-Cohen suspects that he too showed signs of Asperger syndrome.

"Passion, falling in love and standing up for justice are all perfectly compatible with Asperger syndrome," he says. "What most people with AS find difficult is casual chatting - they can't do small-talk."

Glen Elliott, a psychiatrist from the University of California at San Francisco, is not convinced. He says attempting to diagnose on the basis of biographical information is extremely unreliable, and points out that any behaviour can have various causes. He thinks being highly intelligent would itself have shaped Newton and Einstein's personalities.

"One can imagine geniuses who are socially inept and yet not remotely autistic," he says. "Impatience with the intellectual slowness of others, narcissism and passion for one's mission in life might combine to make such an individuals isolative and difficult." Elliott adds that Einstein had a good sense of humour, a trait that is virtually unknown in people with severe Asperger syndrome.

But Baron-Cohen thinks the idea is still worth considering - there may be certain niches in society where people with AS can flourish for their strengths rather than their social skills, he says. "This condition can make people depressed or suicidal, so if we can find out how to make things easier for them, that's worthwhile."

Hazel Muir