Science bites
Updates about the science behind the medicine. Please send in your science bites to dcohen@bmj.com
The world’s most powerful magnetic resonance imaging scanner has been unveiled recently at the University of Illinois, Chicago. Researchers are expecting the machine to revolutionise the way brain research is done by imaging anatomy and metabolism. The new 9.4 Tesla magnet is able to detect signals from sodium, phosphorus, carbon, nitrogen, and oxygen, which will give researchers a more thorough understanding of brain functions and diseases. The new scanner will help identify and monitor many common conditions, such as Alzheimer’s disease, stroke, autism, mental illness, and will also observe and potentially treat cognitive learning disorders, like attention deficit disorder (www.news.uic. edu).
A novel technique for following the migration of cancer cells around the body is described in the latest issue of Nature Medicine (published online, ahead of print publication, on 29 August 2004; www.nature.com /nm; doi:10.1038/nm1096). The researchers used quantum dots (fluorescent microscopic crystals, which are more stable than other fluorescent labels) in living mice to track tumour cells travelling through the blood stream into the lung. Apart from shedding light on what is actually happening, the technology could be useful in the development of more effective cancer treatments.
Researchers from the University of Hong Kong have identified a pool of small biologically active molecules against the severe acute respiratory syndrome (SARS) coronavirus, which is thought to be the causative agent of an atypical pneumonia. The group did a chemical genetic screen to isolate compounds with anti-coronavirus activity. Of 50 240 compounds, they found out that 104 were powerful inhibitors of the virus; of these, two targeted the virus protease specifically, seven targeted the helicase, and 18 targeted a protein which is required for the virus to enter cells. These new anti-viral inhibitors could potentially become anti- SARS drugs in the future (Chemistry & Biology 2004;11:1293-9)
HIV infection damages dopamine associated brain cells, according to a recent study. Wang and colleagues studied 15 HIV positive volunteers, some having symptoms of dementia, and 13 HIV negative volunteers using positron emission tomography to gauge the presence in the brain of dopamine transporters and dopamine receptors. Only HIV positive patients with dementia had many fewer dopamine transporters in the areas of the brain with the greatest number of transporters. Treatments that increase dopamine concentrations may help HIV patients with dementia (published online, ahead of print production, 19 August 2004; www.brain.oupjournals.org) ;doi:10.1093/brain/awh269)
Ginseng extract has been proved to promote wound healing, and to exert anti-tumour effects by opposing actions on the vascular system. Using mass spectrometry to analyse the composition of ginseng, scientists identified different "sterol ginsenoside" fingerprints. A dominance of Rg1 leads to angiogenesis, whereas Rb1 has an opposing effect. It has been proposed that Rg1 could be a prototype for a new group of non-peptide molecules that could trigger therapeutic angiogenesis, such as in wound healing (Circulation 2004;110:1219-25).
studentBMJ 2004;12:349-392 October ISSN 0966-6494
