L ONDRES - Since the first indication in 1995 that "mad cow" had crossed the species barrier in people, causing a deadly new form of brain disease, a key question remains unanswered: How many cases are likely to occur given the long period of illness latency? - perhaps 10 years or more. - It's hard to say whether Britain is facing a silent epidemic or just a handful of cases in excess of 27 diagnosed far
Late last week, the British government announced that it is about to launch a groundbreaking study to try to find. It will review hundreds of tonsils and appendices stored, removed during surgery in recent years, for traces of protein misshapen called "prion" that have been associated with brain disease known as new variant Creutzfeldt-Jakob disease (vCJD).
study was prompted by the case of Tony Barrett, a 45 year old coastguard southwest England, who died of vCJD in June. According to an article in August 29 issue of The Lancet , Barrett had his appendix removed in a local hospital eight months before he first showed symptoms of the disease. When doctors examined the tissue stored evidence misshapen prions, he tested positive. This was the first demonstration that vCJD can be detected before symptoms appear, said James Ironside of the National CJD Surveillance Unit, a co-author of Lancet paper.
The government now expects test more than 1,000 of the 800,000 samples of tonsils and 45,000 samples of the removed appendix and stored each year. Comparison of tissue removed before and up to the outbreak of mad cow in the late 1980s can provide a rough estimate of the extent to which the population harbors prion protein vCJD. The study is too small, however, provide something more than an indication of whether or not there is a widespread problem. "Interpretation of [data] require great caution," said Kenneth Calman, Chief Medical Officer of Great Britain, who announced the study last week.
Government officials and their advisors not yet worked on the ethical rules that will govern the testing program, however. One option is to remove all identifiers so that the fabric can be traced back to the patient. If this is not done, the researchers will face the question of whether to tell patients if prions are detected in their organs.
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