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    <recommendedItem id="20100101_19_425"
                     title="AAN: Industrial Cleaner Again Tied to Parkinson Risk (CME/CE)"
                     score="0.013"
                     href="http://www.medpagetoday.com/MeetingCoverage/AAN/tb/18338?impressionId=1265759182615"
                     
      TORONTO  --  The degreasing agent trichloroethylene (TCE) has been linked to increased rates of Parkinson&apos;s disease among industrial workers in yet another study, this time involving a large, well-studied group of World War II veterans.&lt;br&gt;
&lt;br&gt;Parkinson&apos;s disease developed in individuals with occupational exposure to TCE at more than five times the rate seen in those without such exposure (odds ratio 5.5, 95% CI 1.02 to 30), reported Samuel Goldman, MD, of the Parkinson&apos;s Institute in Sunnyvale, Calif.&lt;br&gt;
&lt;br&gt;Goldman described the research in a phone interview with &lt;em&gt;MedPage Today&lt;/em&gt;. It&apos;s scheduled for presentation here in April at the American Academy of Neurology&apos;s annual meeting.&lt;br&gt;
&lt;br&gt;A previous study in 2008 had fingered TCE as the most likely culprit behind a cluster of Parkinson&apos;s disease cases afflicting workers at a single industrial plant. (See &lt;a href=&quot;http://www.medpagetoday.com/Geriatrics/ParkinsonsDisease/7894&quot; mce_href=&quot;http://www.medpagetoday.com/Geriatrics/ParkinsonsDisease/7894&quot; target=&quot;_blank&quot;&gt;Trichloroethylene Implicated as Risk for Parkinsonism&lt;/a&gt;)&lt;p&gt;&lt;/p&gt;
&lt;p&gt;Also, Goldman said, animal studies have found that TCE is selectively toxic to nigral dopaminergic neurons, the same type of nerve cell that progressively dies off in Parkinson&apos;s disease. He said the chemical&apos;s activity in rodent brains is very similar to that of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), a dopaminergic neurotoxin commonly used to simulate Parkinson&apos;s disease in preclinical research.&lt;/p&gt;
&lt;p&gt;Goldman said the new study was the first population-based analysis to link TCE to the disease.&lt;/p&gt;
&lt;p&gt;It focused on 198 twin pairs in the National Academy of Sciences-National Research Council&apos;s World War II Twins Cohort, which comprises some 16,000 twin pairs overall.&lt;/p&gt;
&lt;p&gt;Members of the all-male cohort, who were born from 1917 to 1927 and served in the war, have been followed since the 1960s. Occupational histories for participants are available along with medical records from the VA healthcare system.&lt;/p&gt;
&lt;p&gt;In those pairs chosen for the current study, records showed that one twin had developed Parkinson&apos;s disease and the other had not. This design largely eliminates genetics as a confounding factor in the analysis.&lt;/p&gt;
&lt;p&gt;Goldman explained that occupational histories for each participant were reviewed by a blinded industrial hygienist and a preventive medicine physician to identify likely exposures to TCE and four other industrial chemicals: xylene, toluene, carbon tetrachloride, and tetrachloroethylene.&lt;/p&gt;
&lt;p&gt;As a single source of exposure, only TCE was significantly associated with development of Parkinson&apos;s disease, Goldman said.&lt;/p&gt;
&lt;p&gt;People working as aircraft mechanics, machinists, plumbers, and electricians likely had regular exposure to TCE, Goldman said. The chemical was commonly used as a &quot;spot&quot; cleaner to remove grease and oils from metal surfaces. It was also used for a time as a dry cleaning solvent, although tetrachloroethylene was more common for that purpose.&lt;/p&gt;
&lt;p&gt;Goldman said no increased risk was seen with xylene or toluene, but there were near-significant trends toward increased Parkinson&apos;s disease risk from carbon tetrachloride and tetrachloroethylene: &lt;ul&gt; &lt;li&gt;Carbon tetrachloride: OR 2.8 (95% CI 0.97 to 7.8)&lt;/li&gt; &lt;li&gt;Tetrachloroethylene: OR 9.0 (95% CI 0.78 to 103)&lt;/li&gt; &lt;/ul&gt;&lt;/p&gt;
&lt;p&gt;Twins exposed to either TCE or tetrachloroethylene were at significantly increased risk, with an odds ratio of 8.1 (95% CI 1.43 to 43) relative to individuals with no exposure to either chemical.&lt;/p&gt;
&lt;p&gt;Goldman said the analysis also examined whether duration of exposure was associated with increased risk. He said the results were in the same pattern as for the yes-no exposure analysis, but the findings were very uncertain because of the relatively small sample size.&lt;/p&gt;
&lt;p&gt;Occupational histories were available for only 99 of the 198 discordant twin pairs and some of the information was obtained by proxy rather than from the participant himself.&lt;/p&gt;
&lt;p&gt;Because of the wide confidence intervals even for the yes-no exposure analysis, the findings need confirmation in a larger study, he said, noting that the best approach would be a cohort study involving people with known, long-term exposure to TCE, compared with well-chosen controls.&lt;/p&gt;
&lt;p&gt;&quot;The study wouldn&apos;t have to be large,&quot; Goldman said. He estimated that 1,000 to 2,000 participants would be adequate to determine if the connection to Parkinson&apos;s disease is real.&lt;/p&gt;
&lt;div style=&quot;float:left;border-style:solid;border-width:1px;border-color:#8dabbc;font-family:arial;font-size:12px;background-color:#DBE9F2;padding:5px;&quot;&gt;&lt;p&gt;The study was funded by the National Institute of Neurological Disorders and Stroke, the Valley Foundation, and the James and Sharron Clark Family Fund.&lt;/p&gt;&lt;p&gt;No potential conflicts of interest were reported.&lt;/p&gt;&lt;/div&gt;&lt;div style=&quot;clear:both;&quot;&gt;&lt;/div&gt;
    </recommendedItem>
    <recommendedItem id="20100101_19_390"
                     title="Vegetative State May Still Harbor Consciousness (CME/CE)"
                     score="0.012"
                     href="http://www.medpagetoday.com/Neurology/GeneralNeurology/tb/18283?impressionId=1265759182615"
                     
      Researchers in England are reporting they have been able to establish limited communication with a man in a persistent vegetative state by using functional magnetic resonance imaging (fMRI).&lt;br&gt;
&lt;br&gt;The 34-year-old man was able to answer simple Yes or No questions by imagining different types of activity, which caused changes in brain activity that could be seen in the machine, according to Martin Monti, PhD, of the Medical Research Council Cognition and Brain Sciences Unit in Cambridge, England, and colleagues.&lt;br&gt;
&lt;br&gt;The finding shows that at least some patients who are otherwise unresponsive may have some residual awareness, the researchers reported online in the &lt;em&gt;New England Journal of Medicine&lt;/em&gt;.&lt;br&gt;
&lt;br&gt;&quot;The incredible thing is that we could never do something like that at the bedside,&quot; Monti told &lt;em&gt;MedPage Today&lt;/em&gt;. Outside of the fMRI machine, he said, the patient remained unresponsive to standard tests.&lt;br&gt;
&lt;br&gt;The study is likely to arouse controversy, Monti conceded, especially in the light of such high-profile cases as that of Terry Schiavo, which eventually went to the U.S. Supreme Court.&lt;p&gt;&lt;/p&gt;
&lt;p&gt;In the Schiavo case, relatives were bitterly divided on whether to withdraw&lt;strong&gt; &lt;/strong&gt;life support for the woman, who had been in a persistent vegetative state for several years.&lt;/p&gt;
&lt;p&gt;&quot;People will have a tendency to overinterpret this,&quot; Monti said, adding &quot;this finding in one patient does not imply that all patients may or may not have the ability to do this.&quot;&lt;/p&gt;
&lt;p&gt;Indeed, the researchers tested 54 people and found only five who could apparently respond to direction by imagining either motor or spatial activity. Imagining those activities uses different parts of the brain and their activation can be seen by the fMRI scan.&lt;/p&gt;
&lt;p&gt;Several of the responders were already what is called &quot;minimally responsive,&quot; meaning that occasionally they were able to react to external stimuli.&lt;/p&gt;
&lt;p&gt;Of those five, the researchers only tried to communicate with one  --  the man in a persistent vegetative state  --  using his ability to reliably activate different brain areas when asked to imagine either playing tennis or looking around a room in his house.&lt;/p&gt;
&lt;p&gt;While in the machine, he was asked simple questions, such whether his father&apos;s name was Alexander. To answer Yes, he was to imagine playing tennis, while for No he was to imagine looking around the room.&lt;/p&gt;
&lt;p&gt;He was able to answer five out of six questions, the researchers reported, adding it was unclear why he was unable to answer the sixth but no brain activity was seen in response to the question.&lt;/p&gt;
&lt;p&gt;Outside experts also cautioned against overinterpreting the results.&lt;/p&gt;
&lt;p&gt;&quot;The percentage of patients showing a response was low, and longer-term follow-up studies are needed to determine whether such fMRI findings by themselves have meaningful predictive value,&quot; argued Alan Faden, MD, of the University of Maryland School of Medicine in Baltimore.&lt;/p&gt;
&lt;p&gt;&quot;This study may well raise questions for some with regard to medical or legal decisions based upon state of consciousness,&quot; Faden said in an e-mail, &quot;but the findings primarily underscore the limitations of current categorizations for diminished states of consciousness.&quot;&lt;/p&gt;
&lt;p&gt;He said that as technology gets better, it will likely mean that doctors will have to modify their diagnostic categories for what he called &quot;states of diminished consciousness.&quot;&lt;/p&gt;
&lt;p&gt;In an accompanying editorial in the journal, Allan Ropper, MD, of Brigham and Women&apos;s Hospital in Boston, wrote that such research is &quot;easily subject to overinterpretation and sensationalism.&quot;&lt;/p&gt;
&lt;p&gt;He cautioned that brain activation was seen only in a few patients and only in those with a traumatic brain injury, rather than global ischemia and anoxia.&lt;/p&gt;
&lt;p&gt;And, he wrote, the brain activity seen in the patients is not evidence of such things as memory, self-awareness, anxiety, or despair. &quot;We cannot be certain whether we are interacting with a sentient, much less a competent, person&quot; Ropper wrote.&lt;/p&gt;
&lt;p&gt;Despite such caveats, the research is &quot;critically important,&quot; according to Michael DeGeorgia, MD, of University Hospitals Case Medical Center in Cleveland.&lt;/p&gt;
&lt;p&gt;It &quot;illustrates both the complexities of this area and the limitations of our bedside clinical examination,&quot; he said in an e-mail, adding that more research will be needed to figure out how to use the technology and how to interpret the results.&lt;/p&gt;
&lt;p&gt;The research &quot;does raise difficult medical and legal questions,&quot; DeGeorgia said.&lt;/p&gt;
&lt;p&gt;&quot;We always need to be upfront and honest with families about what we know for certain and what we do not know for certain,&quot; he said. &quot;In many of these cases, the honest answer is that we cannot be absolutely 100% certain that their loved one isn&apos;t &apos;in there somewhere.&apos;&quot;&lt;/p&gt;
&lt;div style=&quot;float:left;border-style:solid;border-width:1px;border-color:#8dabbc;font-family:arial;font-size:12px;background-color:#DBE9F2;padding:5px;&quot;&gt;&lt;p&gt;The study had support from the Medical Research Council, the European Commission, Fonds de la Recherche Scientifique, the James S. McDonnell Foundation, the Mind Science Foundation, the Reine Elisabeth Medical Foundation, the Belgian French-Speaking Community Concerted Research Action, University Hospital of Liege, the University of Liege, and the National Institute for Health Research Biomedical Research Centre.&lt;/p&gt;&lt;p&gt;The researchers said they had no potential conflicts.&lt;/p&gt;&lt;p&gt;Hopper did not report any conflicts.&lt;/p&gt;&lt;/div&gt;&lt;div style=&quot;clear:both;&quot;&gt;&lt;/div&gt;&lt;p&gt;&lt;em&gt;This article was developed in collaboration with ABC News. &lt;/em&gt;&lt;img src=&quot;http://www.medpagetoday.com/upload/2009/10/1/14357_1.jpg&quot; mce_src=&quot;http://www.medpagetoday.com/upload/2009/10/1/14357_1.jpg&quot; alt=&quot;&quot;&gt;&lt;/p&gt;
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