Magnetic resonance elastography (MRE) is a new, painless way of measuring the stiffness of the deepest muscle fibres by taking snapshots of the problem area with a magnetic resonance imaging (MRI) scanner. By contrast, established techniques for measuring muscle stiffness rely on sensors inserted into the tissue.

MRE works by measuring the wavelength of vibrations sent through the muscle fibres by a vibrating metal plate placed on the skin. Pulsing the magnetic field in the MRI scanner in tune with the mechanical vibrations 鈥渇reezes鈥� the pattern of waves in the muscles, like a stroboscope, allowing the wavelength to be measured.

The stiffness of the muscles can then be calculated using this measure, say researchers from the department of orthopedic surgery at the Mayo Clinic in Rochester, Minnesota.

Kai-Nan An, director of the biomechanics laboratory at the Mayo Clinic, and his team have been testing MRE on human volunteers with a variety of medical problems. They say the main limitation of the technique is the need to confine patients inside an MRI scanner. This means that MRE cannot take measurements as you move around.

Instead the researchers get their volunteers to tense particular muscle groups by bracing themselves against special apparatus that they wear inside the scanner.

Stroke and cerebral palsy

An predicts that MRE will be ready for general use within five years, benefiting athletes and people recovering from injuries, as well as stroke victims and people with cerebral palsy who cannot control their movements because their muscles will not relax. Botox injections or surgery can help, and MRE will enable doctors to target the treatment precisely.

MRE should also help doctors track the progress of diseases that cause muscle to degenerate, such as multiple sclerosis or hypothyroidism. 鈥淚t could be used for many things,鈥� says An. He predicts MRE will even help physiotherapists find precisely which areas are causing pain.

Representatives of the Association of Chartered Physiotherapists Interested in Neurology say the cost of using MRI machines could limit the spread of the technique, but agree it has broad potential.

More than one in three nurses in the UK have been stuck by a needle previously used to inject a patient, and seven per cent have been pricked more than once in the past year, according to the Royal College of Nursing, which represents the interests of British nurses. Street cleaners are also at risk from syringes discarded by intravenous drug users.

Plain latex surgical gloves do not protect people from viruses once they have been punctured or split. But lab tests on the sandwich-like material used for the new glove indicate that it promises to cut the number of virus particles entering a wound by a factor of 15. It reduced infection rates in tests on animals by up to 60 per cent.

The added protection is provided by a layer of viricidal liquid droplets sandwiched between two layers of synthetic rubber. The liquid contains a common broad-spectrum disinfectant based on ammonium salts and is particularly effective against viruses such as hepatitis C and HIV. As soon as a needle or other sharp object punctures the glove, the disinfectant liquid is released onto the wound.

Failed condom

The G-VIR gloves were developed by Paris-based rubber goods firm Hutchinson. The idea came from a failed viricidal condom which had to be uncomfortably thick and could not contain enough disinfectant for the average amount of infected sperm it would have to deal with, says spokesman Gilles Argy. So an antiviral glove looked to be a better product.

The gloves are made by dipping hand-shaped porcelain moulds into a vat of liquid synthetic rubber, then into an emulsion of the disinfectant and once more into the rubber. The layers dry to form a tough sandwich.

While this makes the G-VIR gloves thicker than standard latex gloves, surgeons who tried them out at a hospital in Lyon are said to have adapted quickly to working with them. Many surgeons already wear two pairs of latex gloves when carrying out risky procedures, in any case.

Hutchinson expects full clinical trials to start in late 2003 and is waiting for the results before predicting how effective the gloves will prove in practice.

Carol Bannister, who advises the Royal College of Nursing on occupational health, warns that people in frequent contact with biocides or rubber compounds sometimes develop skin or respiratory problems. So while she welcomes the viricidal gloves as a promising idea, she says the trials will need to assess the long-term effects of wearing them.