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Science & Technology
Medical breakthroughs

It is the first time that congenital blindness has been reversed in an animal larger than a mouse

From Diana J. Choyce
May 21 - Jun 03, 2001

A team of scientists led by University of Pennsylvania researchers produced sight in three puppies that were genetically blind from birth. It is the first time that congenital blindness has been reversed in an animal larger than a mouse. The researchers replaced a mutant gene that caused blindness with a gene that they had created in a lab. Within a few weeks after the injection, the dogs could see enough to follow human movement and to negotiate a path around furniture. "We didn't expect a result this spectacular," said Dr. Jean Bennett of the Scheie Eye Institute. "We were really very, very excited when we first got a glimmer that we had actually restored vision to these dogs which had been previously blind." The findings derived from this research could help restore sight to the nearly people with a genetic disease called Leber congenital amaurosis (LCA), the same disease that caused the blindness in the dogs. It could also help hundreds of thousands of others with similar forms of blindness. The gene was created in the laboratory at Cornell from molecular techniques in which they created a clone of the gene, sent that constructed gene to a lab, where they created a virus that allows the gene to be inserted into the retina. Though a rare condition, LCA is one of the most severe blinding diseases because it affects children, and has a number of other symptoms, such as roving eye movement and inability to look in one place. There is a lot to be done first before researchers can advance to human trials, said Dr. Gregory Acland, a research veterinarian at Cornell University. Acland says he expects it will take about four years to get to that point. Researchers have to look at a variety of factors. Human vision is different from dog vision because there is a different sense of acuity. Researchers would also have to determine the dose, and the frequency of the treatments for humans.

The overuse of antibiotics have caused great concern over the last decade. Many conditions have become resistant to this type of drug therapy. But scientists have been studying just how antibiotics disrupt the normal function of cells. They believe the breakthrough could lead to the development of new drugs to overcome the increasing problem of resistance to current antibiotics. A team from the Medical Research Council (MRC) has uncovered a detailed picture of how cells manufacture proteins by translating the information encoded in genes. A structure called ribosome controls the manufacture of protein in cells. Scientists have documented the detailed process by which the ribosome builds proteins from component parts called amino acids following exact specifications contained in the DNA of the genes. Antibiotics appear to induce a ribosome to make a "mistake" and allow the wrong amino acid to be added onto the protein chain. This renders the protein ineffective. Now that this process has become clear, it might be possible to develop new drugs that destroy bacteria during their development. Lead researcher Dr Venki Ramakrishnan explained: "As biologists we are fascinated by these results because of their fundamental importance in understanding how the genetic code gets translated into proteins. "However, pharmaceutical and biotech companies are keenly interested because this research not only helps us to understand how many known antibiotics work but also helps us to understand the basis of certain kinds of resistance. "This will hopefully allow us to design new antibiotics in the future that can overcome the growing world-wide problem of resistance."

A University of Pittsburgh researcher said he had developed an artificial lung that could be implanted temporarily in people with emphysema or other severe respiratory problems to take some of the breathing load off their lungs. Dr. Brack Hattler told Reuters his Hattler Respiratory Catheter, which was expected to begin clinical trials in Europe next year, can provide about half the oxygen an adult body needs and was designed to be implanted for as long as two weeks. He said up to 750,000 patients in the United States each year could use the device, including emphysema patients who need breathing assistance while recovering from colds and other complications. Hattler said the device also could help patients who suffered trauma to their lungs, such as smoke inhalation, and who need breathing help while their lungs heal."Every year in the United States we have between 150,000 and 200,000 people who are dying and there's been a need to take over the function of the lungs and provide support while the lungs heal,'' said Hattler, a professor of surgery at the University of Pittsburgh School of Medicine. He said he hopes to have the device approved for use in the United States by the end of 2003. The device, about 18 inches long, is inserted through a vein in the leg and is threaded up into the vena cava, the major vein returning blood to the heart. It consists of hollow fiber membranes that introduce oxygen into the blood and remove carbon dioxide. The oxygen source sits outside the body and is attached to the catheter by tubes. The Hattler device would be the second artificial lung tested on humans. About 10 years ago, clinical testing of another device was stopped because it failed to work effectively. Hattler said the major design update since the first artificial lung is a small balloon, about the diameter of a nickel, that inflates and deflates rapidly to help move the blood through the plastic membranes.

These three advances in medicine are but a few of the many to be seen in the near future. If man continues to use research funds wisely, and continues to strive for knowledge, the future will indeed be brighter for mankind. An eradication of all diseases is not a wise or attainable goal, but to relieve the suffering of mankind, and to cure diseases that man has created, would be wonderful indeed.