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Many people use the World Wide Web to get information; however, it is not always easy to obtain the desired information, since the number of Web sites and Web pages is huge, and most of them are not structured. To solve this problem, some Web site managers visualize their sites' structure and/or keyword information; this is an effective way of developing an easy-to-navigate Web site. Even if both functions are provided, however, in conventional systems they are provided as separate functions, and no relation exists between them; a user cannot see and operate a site map and keyword information as related information. Providing a site map with keywords is a new technique for visualizing and navigating Web sites. It displays both a Web site's structure and keyword information on a site map and displays the relation between them. This technique not only allows both sets of information to be visualized on the same screen, but also makes it possible to interact with one through the other: a user can interact with a Web site's structure through its keyword information, and vice versa.

Allergic rhinitis is an inflammatory disease of the nasal mucosa, induced by histamine, leukotrienes, and other substances released from mast cells. Fexofenadine hydrochloride, the active metabolite of terfenadine, is a novel, nonsedating antiallergic drug having H₁ receptor antagonistic activity. Fexofenadine is effective for the treatment of allergic rhinitis. However, its mechanism of action in attenuating nasal congestion has not yet been elucidated. Therefore, we first examined the effects of fexofenadine on a guinea pig model of antigen-induced rhinitis. We also evaluated the effects of mepyramine, zafirlukast and ramatroban in this model; these drugs are an H₁ receptor antagonist, a selective leukotriene antagonist and a selective thromboxane antagonist, respectively. Rhinitis was induced by ovalbumin (OVA) instillation into the nasal cavity of animals that had been sensitized by two earlier OVA injections (s.c. and i.p.). The nasal airway resistance was measured for 45 min after the challenge. Fexofenadine hydrochloride (20 mg/kg) and terfenadine (20 mg/kg) administered orally 70 min prior to the challenge significantly inhibited (fexofenadine, p < 0.001, terfenadine, p < 0.05) the increase in nasal airway resistance. Ramatroban (30 mg/kg) administered orally 60 min prior to the challenge also significantly inhibited (p < 0.05) the increase in nasal airway resistance. In contrast, mepyramine (3 mg/kg i.v.) and zafirlukast (3 mg/kg p.o.) failed to reduce the increase in nasal airway resistance. These results suggest that thromboxane may be involved in the increase in the nasal airway resistance in this model. Accordingly, fexofenadine may reduce the increase in nasal airway resistance by inhibiting the release of chemical mediators, including thromboxane, that are involved in the increase in nasal airway resistance in this model.