Ischemic stroke as the sole manifestation of human immunodeficiency virus infection.

Caffeine and Stroke To the Editor: Several investigators have recently shown that rodents chronically given caffeine develop upregulation of adenosine receptors and tolerate brain ischemia better than rodents not given caffeine.'The upregulation results from caffeine's action as a competitive antagonist of adenosine. These findings provide further evidence for a neuroprotective effect of adenosine in the setting of brain ischemia. Rudolphi et al conclude their article by saying that "An epidemiologic study of caffeine intake and stroke may prove quite interesting." Is not the investigation in humans by Grobbee et a] such a study? They reported that chronic caffeine intake by men was inversely related to the risk of fatal and nonfatal stroke and that the trend for the association was statistically significant. The trick is to drink plenty of coffee and tea to upregulate adenosine receptors, but somehow to avoid caffeine-containing beverages once the stroke begins so that caffeine does not block adenosine from exerting its beneficial effect.