Beneficial effects of leukotriene receptor antagonists in the prevention of cedar pollinosis in a community setting.

BACKGROUND: In recent years, many countries have experienced an increase in the prevalence of allergic rhinitis. No effective approach is currently available to prevent the onset of symptoms in allergic individuals. Pranlukast, a leukotriene receptor antagonist with a good safety and efficacy record for the management of allergic inflammation, may be appropriate for early intervention in the management of pollinosis. OBJECTIVE: To investigate the efficacy of pranlukast as an early intervention in the control of cedar pollinosis. METHODS: In a double-blind comparative study, pranlukast (n = 102) or placebo (n = 91) was administered to cedar pollinosis patients immediately before the start of the dispersion season and continued for 4 weeks. Subsequently, pranlukast was administered to all patients for 2 weeks until the end of the cedar pollen dispersion season (mid-March). All patients were carefully monitored for severity of nasal symptoms, symptom scores, medication scores, symptom-medication scores, and quality of life (QOL). RESULTS: Compared with placebo, therapy with pranlukast before and during the dispersion of cedar pollen in these patients significantly improved nasal symptoms (paroxysmal sneezing, rhinorrhea, and nasal congestion), symptom scores, and symptom-medication scores. The drug also significantly reduced deterioration of QOL, and improved nasal symptoms and QOL throughout the dispersion period. CONCLUSION: Administering pranlukast immediately before the beginning of cedar pollen dispersion is effective in reducing symptoms of allergic rhinitis throughout the dispersion period.

Seasonal changes in antigen-specific T-helper clone sizes in patients with Japanese cedar pollinosis: a 2-year study.

BACKGROUND: Allergic rhinitis (AR) is a typical type I allergic disease that occurs through the induction of allergen-specific effector T cells. Once established, new effector T cells derive mostly from memory T cells that are capable of surviving for extended periods, although the mechanisms by which these memory functions are maintained have not yet been clarified. In particular, the exact life-span of memory T cells is still not well understood. OBJECTIVE: Pollinosis patients seemed to be suitable subjects to investigate because such patients are exposed to antigens strongly for only a limited period once a year. We compared the seasonal changes in memory T-helper type 2 (Th2) between pollinosis and perennial allergic subjects. METHODS: The clone sizes of the Japanese cedar pollen-specific memory Th cells were measured by an ELISPOT assay using specific peptides from the patients with cedar pollinosis, and the seasonal changes were noted. This study was performed for 2 years. The cedar-specific IgE levels in the peripheral blood were also studied. Mite allergy patients were also enrolled in the study. RESULTS: The Japanese cedar-specific IL-4-producing Th2 cells were detected in all patients examined, although the number of cells was low. These Th memory cells increased during the pollen season and decreased during the off-season. However, more than 60% of the cedar-specific memory Th2 cells survived up to 8 months after the pollen season. The cedar-specific IgE levels exhibited changes similar to the cedar-specific Th cells. On the other hand, there was no drifting of Th memory clone size with the mite allergics, and the IgE levels also did not change. CONCLUSIONS: While pollen-specific Th cells decreased after pollen exposure, their memory functions continued. Memory clone size maintenance therefore requires repetitive antigen irritation.

Selective caries removal with air abrasion.

The purpose of this study was to evaluate selective caries removal using an air-abrasive technique. Alumina powders, glass beads, crushed glass powders, and crushed powders of polycarbonate resin were applied to intact human enamel, dentin, and artificially demineralized dentin (caries-model dentin). Furthermore, the effect of the particle size of abrasives and air pressures on the abraded depths was examined. When alumina powders and glass beads were used, the abraded depths of enamel, dentin, and caries model increased as the particle size and air pressure increased. Alumina powders and crushed glass powders abraded intact enamel and dentin more than the caries-model dentin, whereas glass beads abraded the caries-model dentin more than the intact enamel and dentin. Only crushed powders of polycarbonate resin abraded the caries-model dentin without reducing intact enamel and dentin. With hard particles, such as alumina powders, glass beads, or crushed glass powders, selective caries removal by the air-abrasive technique appeared to be difficult to achieve, even if the particle size and the air pressure were changed. Crushed powders of polycarbonate resin that reduced only the caries-model dentin are harder than caries-model dentin, but softer than intact enamel and dentin. This study elucidated the possibility of selective carious dentin removal with the air-abrasive technique.