Effect of histamine on the permeability of the nasal mucosa in vivo.

OBJECTIVE: Histamine is one of the chemical mediators released during the acute phase of allergic rhinitis and is considered to cause the increase in epithelial permeability observed. We tried to examine the effect of histamine on nasal mucosal permeability in vivo. MATERIAL AND METHODS: Histamine at different concentrations was administered to the nostrils of healthy subjects and the nasal transepithelial potential difference (PD) was measured. We also examined nasal mucosal permeability by means of a histochemical technique using horseradish peroxidase (HRP) in guinea pigs. RESULTS: Administration of 10(-1) M histamine significantly reduced the nasal PD in healthy subjects. After administration of 5.4 x 10(-1) M histamine to the noses of guinea pigs, most ofthe intercellular spaces showed positive reactions to HRP and this effect was significantly inhibited by pretreatment with mepyramine and the antihistamine bepotastine besilate. CONCLUSION: These results indicate that histamine plays an important role in the change in mucosal permeability observed in allergic rhinitis in vivo via the histamine H1 receptor.

[Prediction of the total Japanese cedar pollen counts based on male flower-setting conditions of standard trees].

We made a prediction of the Japanese cedar (Cryptomeria japonica) pollen counts at Tsu city based on male flower-setting conditions of standard trees. The 69 standard trees from 23 kinds of clones, planted at Mie Prefecture Science and Technology Promotion Center (Hakusan, Mie) in 1964, were selected. Male flower-setting conditions for 276 faces (69 trees x 4 points of the compass) were scored from 0 to 3. The average of scores and total pollen counts from 1988 to 2000 was analyzed. As the results, the average scores from standard trees and total pollen counts except two mass pollen-scattered years in 1995 and 2000 had a positive correlation (r = 0.914) by linear function. On the mass pollen-scattered years, pollen counts were influenced from the previous year. Therefore, the score of the present year minus that of the previous year were used for analysis. The average scores from male flower-setting conditions and pollen counts had a strong positive correlation (r = 0.994) when positive scores by taking account of the previous year were analyzed. We conclude that prediction of pollen counts are possible based on the male flower-setting conditions of standard trees.

Mucociliary transport function and damage of ciliated epithelium.

The influence of epithelial damage on mucociliary transport was studied in relation to the amount of mucus. The mucosal epithelium of mucus-depleted frog palate was dissected and mounted on a plastic plate. Mechanical damages were created on the frog mucosa by pressing a different thickness of boards (2, 3, 5, and 8 mm). Two different amounts of frog mucus (7.9 microL [small amount of mucus (S-mucus]]) and 51.0 microL [large amount of mucus [L-mucus]]) were acpplied on the frog mucosa witih and without mucosal damage. There was no difference in mucociliary transport rate (MTR) on undamaged frog mucosa between S-mucus and L-mucus. However, on the damaged mucosa, MTR of S-miucus was significantly decreased compared with that of L-mucus. Moreover, capability of mucus transportation across the mucosal damage was significantly lower in S-mucus than in L-mnucus. Results indicate that the larger the mucus amount becomes, the more the mucus travels the damaged epithelium. Moreover, MTR of L-mucus was decreased with increasing the degree of epithelial damage. This study indicates that the degree of loss of cilia is an important factor of mucociliarn deceleration.