MEDICAL TECHNOLOGY: Limitations show up in deep brain stimulation to treat Parkinson’s
A "BRAIN pacemaker" known as deep brain stimulation remains an effective treatment for Parkinson’s disease for at least three years, say US scientists in a recent issue of the journal, Neurology. However, while improvements in motor function are shown to remain stable, there are gradual declines in health-related quality of life and cognitive abilities.
First author of the study is Dr Frances Weaver, of Loyola University Chicago Stritch School of Medicine. Weaver was one of the lead investigators of a paper in the New England Journal of Medicine in 2010 that found that motor functions remained stable for two years in patients who had deep brain stimulation.
Her additional analysis has extended the follow-up period to 36 months.
Deep brain stimulation is a treatment for Parkinson’s patients who no longer benefit from medication, or who experience unacceptable side effects. It is not a cure, and it does not stop the disease from progressing, say specialists.
In the right patients, it can significantly improve symptoms, especially tremors, and can relieve muscle rigidity that causes decreased range of motion.
In the procedure, a neurosurgeon drills a small hole in the skull and inserts an electrode a few centimetres into the brain, say the researchers. A connecting wire from the electrode runs under the skin to a battery implanted near the collarbone. The electrode delivers mild electrical signals that effectively reorganise the brain’s electrical impulses.
The procedure can be done on one or both sides of the brain.
Certain drugs, including some vaccines and manufactured insulin, are temperature sensitive, which is why pharmacy fridges are supposed to keep them within a range of 2º C to 8º C.
If the drugs are exposed to temperatures outside of this range for some time, their effectiveness cannot be guaranteed, say specialists.
Pick n Pay is using local remote monitoring and control technology to improve the visibility and control of the temperature in its pharmacy division’s fridges.
The aim is to ensure that temperature-sensitive drugs are safely managed at all times, the company says in a press release.
"The ethical considerations around temperature-sensitive drugs are enormous," says Ian Lester, CEO of Beyond Wireless, a local company that has been working with the retail food chain’s pharmacy operations.
"The shelf-life of many medications is dependent on proper temperature control," says Lester.
"The importance of accurate cold chain management in the pharmaceutical sector cannot be understated."
Lester says suppliers and distributors may manage the cold chain well, but hand the medication over to retailers that unknowingly break the cold chain in-store.
"The South African Pharmacy Council’s Code of Good Pharmacy Practice requires retail pharmacists to check and record the temperature of their fridges manually twice a day, and to have the fridge linked to an alarm system," he says.
Sometimes, the manual logging method and traditional security alarm systems fall short.
For example, if a pharmacist relies solely on the manual logging method, they might experience a power failure during the night, Lester says; when the pharmacist checks the fridge the next morning, the power may have been restored, and the temperature would have returned to the allowed range.
"They will never know the drugs were out of range, how far and for how long they went out of range, all of which is crucial in deciding what to do with the drugs," he says.
Strict storage specifications within the industry mean that once insulin, vaccines and other temperature-sensitive drugs have been outside of the allowed temperature range for certain periods of time, they must be disposed of.
The World Health Organisation reports over 50% vaccine wastage around the world, and part of this enormous amount of wastage is attributed to poor cold chain management.
Lester says the most serious and often overlooked problem is fridges in which temperatures fall too low.
A fridge that goes below 0º C does more harm to insulin and vaccines than a fridge that goes above 8º C, as it reduces shelf life, he says; going below 0º C can destroy live cultures of some vaccines and alters the molecular structure of most most insulin.
In extreme cases, drugs may freeze and thaw repeatedly — the worst case scenario in terms of maintaining efficacy.
Sue Jarvis, head of Pick n Pay’s pharmacy division, says the Beyond Wireless solution addresses a wide range of possible temperature problems.
"The solution is an automated web interface that constantly monitors the temperatures within the pharmacy and the fridges, 24 hours a day, and sends alarm signals when temperatures are out of the specified ranges," Jarvis says.
It means the quality and safety of the medicine can be guaranteed, she says.
The technology requires minimal training, and as the secure web interface can be accessed remotely from any computer, tablet, or smart phone with an internet connection, it is convenient for pharmacists, who can see the temperature of fridges at any time, from anywhere, says Jarvis.
Health News correspondent
Surgeons and anatomists have been examining the geometry of muscle fibres in the heart for decades, and they have long known that muscle cells are aligned to form helices that wind around the heart’s ventricles.
These analyses have been confined largely to the level of individual fibres.
Partly because of the limitations of traditional histology techniques, little work has been done on the more-complex geometry of groups of fibres.
Working with collaborators at Eindhoven University of Technology in the Netherlands, and Yale University in the US, Canadian scientists at McGill University have used a combination of Diffusion Magnetic Resonance Imaging (DMRI) and computer modeling to reveal the way that bundles of fibres bend together.
The researchers examined images of the heart tissue of rats, humans and dogs, and found the same pattern.
"You can think of it as analysing a clump of hair instead of an individual hair strand," says Dr Kaleem Siddiqi, a professor in McGill’s School of Computer Science.
"We’ve discovered that the clump bends and twists in the form of a particular minimal surface, the generalised helicoid — and this is true across species. It’s not particular to just one mammal.
"The implications of these findings are broad," says Siddiqi.
The knowledge could be used, for example, to provide a scaffold to guide the repair of heart-wall damage caused by heart attacks, he says.
While regeneration of muscle tissue is a major area in bioengineering, most developments in this field have involved skeletal muscle tissue — such as that in arms and legs — which is arranged in a different, more linear structure, Siddiqui says.