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American Thoracic Society Journal news tips for November 2003 (second issue)

American Thoracic Society

Researchers have demonstrated for the first time that 3 weeks of dietary supplementation with fish oil capsules markedly reduces the severity of exercise-induced bronchoconstriction (EIB) in elite athletes. The investigators conducted a randomized, double-blind crossover study in 10 elite athletes with EIB and 10 elite athletes without EIB. The participants entered the study on their normal diet. They then received either fish oil capsules containing omega-3 polyunsaturated fatty acids (PUFA) or placebo capsules filled with olive oil daily for 3 weeks. In subjects with EIB, the n-3 PUFA diet improved post-exercise pulmonary function compared with normal and placebo diets. (EIB is a condition characterized by transient airway narrowing either during or after exercise, which results in a reduction in post-exercise pulmonary function.) When measured at 15 minutes post-exercise, pulmonary function test results showed a 3 percent decrease in PUFA diet participants, compared with a 14.5 percent decrease on the placebo diet, and a 17.3 percent decrease on the normal diet. Pro-inflammatory mediators all decreased significantly on the fish oil diet compared with the other two diets. Involved in the study were 10 triathletes, 5 cross-country runners, and 5 track runners. Participants were equally divided between males and females. The study appears in the second issue for November 2003 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.

SMALL STUDY SHOWS POSSIBLE NEW TREATMENT FOR OBSTRUCTIVE SLEEP APNEA

Swedish investigators report on a randomized, placebo-controlled study showing that the acetylcholinesterase inhibitor physostigmine (PHYS) reduces sleep-disordered breathing, mostly during rapid eye movement (REM) sleep, in patients with moderate to severe obstructive sleep apnea (OSA). The investigators studied 10 male patients between the ages of 35 and 56 who had OSA by infusing them with PHYS or placebo randomly over two study nights. (Sleep disordered breathing encompasses a wide spectrum of conditions from intermittent air flow restriction to complete airway collapse called OSA. As part of the process, sleep apnea usually involves the temporary cessation of breathing for more than 10 seconds many times during the night.) For the men involved in this study, their apnea/hypopnea index, which measures the number of breathing pauses, ranged from 12 to 73 events per hour. The subjects received a full night's sleep study starting each evening after they had been give either active medication or placebo (depending on the crossover). (PHYS is a cholinergic alkaloid obtained from the Calaban bean which is produced by a West African perennial shrub. PHYS has been used for some time in the treatment of glaucoma, as well as for atropine and organophosphate intoxication.) During the last one-third of the medication night, coinciding with a predicted plasma concentration steady state of infused PHYS, the non-REM sleep AHI in the patients decreased by 19 events per hour and the REM sleep AHI by 34 events per hour. According to the authors, the REM sleep AHI was most pronounced in subjects with the lowest baseline heart rate, as well as in leaner patients. The study appears in the second issue for November 2003 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.

NO CONFIRMATION SEEN FOR RHINITIS/BLOOD PRESSURE CONNECTION

In a study by different investigators which was nearly three times larger than the original research, medical scientists found no statistical association between blood pressure in men either with or without a common inflammation of the mucous membrane in the nose called rhinitis. German researchers studied data from 896 subjects who had participated in the European Respiratory Health Survey and another study. After adjusting for age, body mass index, and smoking, they found that neither average systolic nor diastolic blood pressure was statistically different between men with or without rhinitis. In the prior study, French investigators assessed 316 adults, ages 28 to 56 years, as part of the European Community Health Survey. They found that men with rhinitis had higher systolic blood pressure and more hypertension than those without the upper respiratory disorder. (Rhinitis is a common inflammation of the mucous membrane of the nose, usually associated with nasal discharge.) Neither study found any association between rhinitis and elevated blood pressure in women. The research appears in the second issue for November 2003 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.

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For the complete text of these articles, please see the American Thoracic Society Online Web Site at http://www.atsjournals.org. For either contact information or to request a complimentary journalist subscription to ATS journals online, or if you would like to add your name to the Society's twice monthly journal news e-mail list, contact Cathy Carlomagno at 212-315-6442, or by e-mail at ccarlomagno@thoracic.org.

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