Ischemic stroke is the most common lifethreatening neurological disease and has limited therapeutic options. One component of ischemic neuronal death is inf lammation. Here we show that doxycycline and minocycline, which are broad-spectrum antibiotics and have antiinf lammatory effects independent of their antimicrobial activity, protect hippocampal neurons against global ischemia in gerbils. Minocycline increased the survival of CA1 pyramidal neurons from 10.5% to 77% when the treatment was started 12 h before ischemia and to 71% when the treatment was started 30 min after ischemia. The survival with corresponding pre-and posttreatment with doxycycline was 57% and 47%, respectively. Minocycline prevented completely the ischemiainduced activation of microglia and the appearance of NADPH-diaphorase reactive cells, but did not affect induction of glial acidic fibrillary protein, a marker of astrogliosis. Minocycline treatment for 4 days resulted in a 70% reduction in mRNA induction of interleukin-1␤-converting enzyme, a caspase that is induced in microglia after ischemia. Likewise, expression of inducible nitric oxide synthase mRNA was attenuated by 30% in minocycline-treated animals. Our results suggest that lipid-soluble tetracyclines, doxycycline and minocycline, inhibit inf lammation and are neuroprotective against ischemic stroke, even when administered after the insult. Tetracycline derivatives may have a potential use also as antiischemic compounds in humans.

Indoor air bacteria and fingal spore levels were studied in 71 non‐complaint homes. lk data were analyzed according to the season and the higher limit of the range within which 95% of the cases fall was computed. On the basis of the data the following highest normal levels are proposed for winter: for bacteria 5000 cfulm3 and for fingal spores 500 cfulm3. The recommended levels apply in a subarctic climate for urban and suburban homes when the measurements are made using the same method as in this study. We recommend that if abnormal indoor sources are suspected, indoor samples should be taken in winter when the ground is frozen and covered with snow. At that time, the background levels are at their lowest and the abnormal indoor sources are most easily detected. lk recommended levels should not be used as an indicator of a health risk, but as an indication of abnormal indoor sources or insufficient ventilation.

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