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Sunday, May 20, 2007


From today till as long back as the Emperor Nero (immortalized by his playing the fiddle while Rome burnt) man has used glasses to see better, whether for watching gladiatorial contests or for reading the fine print of The Telegraph. The normal lens of the human eye is a soft pliable gel that changes its curvature depending on how far or near an object is being focused upon by the individual. This is called accommodation, a process that helps a man watch a movie screen and his ticket number in a second’s gap without blurring or squinting. As man ages the gel like material in the lens in his eyes becomes stiff and fibrous. In that state it cannot change shape and accommodate to near vision. This is why the elderly need glasses for reading. These, say forecasters in the web portal, will soon be historical curiosities.
Scientists at the University of Michigan have developed a tool that uses 'ultrafast' lasers that create microbubbles inside the lens of the eye that soften the age-stiffened fibers. This allows the doctor to detect stiff fibers (those that resist the softening process). These are then removed with the help of lasers. The lens becomes softer and gets back to normal. After this non-invasive procedure, normal vision is restored. VoilÄ, no glasses!
The microbubble is now the froth of Sonoporation, a process that is the research darling of biophysicists all around the world today.
What exactly is Sonoporation about? How is it going to change the world of health care?
In this revolutionary technology, microbubbles of perfluorocarbons are coated with a shell or coating of albumin, gold or a polymer and injected into a vein of the body. When the microbubbles reach the target organ, like the heart or brain for example, they are targeted by ultrasound energy from an external machine. The ultrasonic waves cause these microbubbles to explode instantly. This causes holes to form in the membranes of cells of the organ, allowing delivery of drugs or other agents into the specific desired site. The entire process is done without putting in instruments or tubes inside the body, unlike current modalities of treatment.
Take the example of a common disease like a brain stroke that is usually due to a block caused by a clot in one of the cerebral arteries that supply oxygen to the organ. Using the technology, scientists in Hospital Vall d’Hebron in Barcelona dissolved the clots in 71 percent of patients, almost double the success rate of the conventional clot dissolution with a drug called tPA. The potential impact of this therapy in stroke management is awesome with earlier and more complete recovery from the crippling disease, says Carlos Molina, lead author of the article that appeared in a leading journal. A randomized trial for evaluation of the technique is now in progress.
Similar results are expected in the treatment of another common disease caused by an arterial clotting process, the heart attack. Blocked coronary arteries that cause damage to the heart muscle can be opened up using microbubbles. This could potentially reduce the numbers of invasive procedures like angioplasties and bypass surgeries in the future. Cardiologists, however, can take solace from the fact that their patients who develop re-stenosis (narrowing of the coronary arteries, a failure of treatment) after angioplasties can be successfully treated with sonoporation.
A very impressive characteristic of the microbubble is its ability to carry drugs into places that are inaccessible through normal means. The best example is the brain, where the blood-brain barrier prevents most drugs from reaching the grey matter. The use of Sonoporation is opening up enticing prospects for drug treatment for incurable diseases like Alzheimer’s, as evidenced by research in the University of California Davis. In this disease, treatment options have not developed because of the frustrating inability of drugs to reach the affected grey cells.
In the erupting research on gene therapy and molecular biology, microbubbles are being viewed as excellent vehicles of non-invasive treatment. In patients with Type I diabetes, the pancreas lacks the ability to produce the glucose reducing hormone insulin. Paul Grayburn at the Baylor University in Dallas has used UTMD (Ultrasound Targeted Microbubble Destruction) to deliver insulin genes carried in microbubbles to the rat pancreas. Says Grayburn, “Not only was their blood sugar lowered, but there was no evidence of any damage to the pancreas”. The implication for diabetics is a cure from the disease, without the need to take daily insulin injections.
With more and more complex diseases appearing to be curable in the near future, biophysicists seem ready to open the bubbly to celebrate. After all, alcohol can cross the blood brain barrier easily!

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