Prevalence of pollen-induced allergic rhinitis with high pollen exposure in grasslands of northern China.

BACKGROUND: The aim of this study was to investigate the prevalence of epidemiologic and physician-diagnosed pollen-induced AR (PiAR) in the grasslands of northern China and to study the impact of the intensity and time of pollen exposure on PiAR prevalence. METHODS: A multistage, clustered and proportionately stratified random sampling with a field interviewer-administered survey study was performed together with skin prick tests (SPT) and measurements of the daily pollen count. RESULTS: A total of 6043 subjects completed the study, with a proportion of 32.4% epidemiologic AR and 18.5% PiAR. The prevalence was higher in males than females (19.6% vs 17.4%, P = .024), but no difference between the two major residential and ethnic groups (Han and Mongolian) was observed. Subjects from urban areas showed higher prevalence of PiAR than rural areas (23.1% vs 14.0%, P < .001). Most PiAR patients were sensitized to two or more pollens (79.4%) with artemisia, chenopodium, and humulus scandens being the most common pollen types, which were similarly found as the top three sensitizing pollen allergens by SPT. There were significant regional differences in the prevalence of epidemiologic AR (from 18.6% to 52.9%) and PiAR (from 10.5% to 31.4%) among the six areas investigated. PiAR symptoms were positively associated with pollen counts, temperature, and precipitation (P < .05), but negatively with wind speed and pressure P < .05). CONCLUSION: Pollen-induced AR (PiAR) prevalence in the investigated region is extremely high due to high seasonal pollen exposure, which was influenced by local environmental and climate conditions.

[Changes in adhesion features of leukocytes in rats with severe burns].

Twenty-four rats were divided into 3 groups: normal controls (8), simple burned (8), burned plus Polygonum cuspidatum (p.c.)-treated (8). Three hours after burn, 3ml of whole blood was drawn to isolate polymorphonuclear neutrophilic leucocytes (PMNs). Confluent monolayer of rat microvessel endothelial cells was grown in a parallel plate of flow chamber. PMNs were driven through the flow chamber under different wall shear stresses. Leukocyte-endothelia adhesion was observed with an Olympus inverted microscope and recorded with a colour microscopic TV set. The adhesive characteristic curve of leukocyte was significantly different between the normal and burned groups. The number of PMNs adhesive to endothelium increased obviously 3 hours after burn. Under 0.196 Pa of wall shear stress, the adhesion rate of PMNs was 81.2 + 4.1% in the burned group and 58.8 + 4.6% in the normal group. The PNMs adhesion rate was decreased to near normal in p.c.-treated group. The average survival time in the burned group was 4.1 + 1.2 hours, much lower than that in the p.c. treated group (33.2 + 15.8 hours). However, in the simple burned group, one rat survived for 24 hours and its PMNs adhesive curve was similar to that of the normal or p.c.-treated groups. The findings indicate that PMNs adhesion features increase apparently after severe burn, which is closely related to the survival rate.