Sensitization to airborne and food allergens in Reykjavík (Iceland) and Uppsala (Sweden) - a comparative study

BACKGROUND: The aim of this study was to compare the prevalence of atopic sensitization and possible risk factors for allergies in two ethnically similar but geographically widely separated urban populations. METHODS: Data from two centers of the European Community Respiratory Health Survey, Reykjavik, Iceland, and Uppsala, Sweden, were utilized. This included a structured interview, skin prick tests, and blood samples for total and specific IgE for common aeroallergens. Additional measurements of specific IgE antibodies to common food antigens were performed. Furthermore, data on social environment, lifestyle, air pollution, and meteorologic variables were compared. RESULTS: Skin prick tests were done on 540 individuals in Reykjavik and 527 in Uppsala. The overall prevalence of at least one positive prick test was 20.5% in Reykjavik and 34.2% in Uppsala (P<0.001). Total and specific IgE were measured in serum from 521 subjects in Reykjavik and 472 in Uppsala. The geometric mean value for total IgE was significantly lower in Reykjavik (13.4 kU/l) than in Uppsala (24.7 kU/l) (P<0.001). Similarly, the overall prevalence of at least one specific IgE to airborne allergens was 23.6% in Reykjavik and 32.3% in Uppsala (P<0.01). Specific IgE to a food panel (fx5) was measured in 502 subjects in Reykjavik, and 434 in Uppsala. In Reykjavik, 20 individuals (4.0%) were positive to one or more of the allergens in the food panel compared to 27 (6.0%) in Uppsala. When the single allergens present in the food panel were measured, altogether 16 positive reactions were found in Reykjavik compared to 47 in Uppsala (P<0.05). CONCLUSIONS: The prevalence of sensitization to both airborne and food allergens was lower in Reykjavik than in Uppsala. The difference may be due to environmental and/or dietary differences or to some yet undefined factor.     

Endoscopic cryotherapy: experimental results and first clinical use

BACKGROUND: Cryotherapy or the application of extreme cold has many potential applications in gastroenterology including tissue destruction and hemostasis but until now its development has been prevented by the lack of a delivery device suitable for use through the endoscope. We report here our experience with prototype devices using both liquid nitrogen driven by a cryosurgical system and cryogenic refrigerants (nitrous oxide and carbon dioxide) at or near ambient temperature. METHODS: Cryotherapy was applied to the distal esophageal mucosa of dogs via a flexible catheter passed through an upper endoscope. In other dogs, cryotherapy was used for hemostasis in a bleeding ulcer model. The procedure was also used for palliation in a 58-year-old man with unresectable adenocarcinoma of the stomach with pyloric channel obstruction. RESULTS: Freezing of the superficial mucosa was nearly instantaneous. All dogs survived the procedure and appeared to thrive. Histologic evaluation revealed significant necrosis of the superficial epithelial layer accompanied by a fibrinocellular infiltrate on the surface. These markers of acute injury subside by the fourth to sixth day and are replaced by regenerating epithelium, a process that is virtually complete by day 10. In the hemostasis experiments, bleeding ceased immediately after cryospraying of the lesions but resumed on thawing in most cases. Application of cryotherapy in the patient resulted in reduction of the pyloric mass with no immediately apparent adverse effects. CONCLUSIONS: These data, although preliminary, demonstrate the feasibility of endoscopic cryotherapy using a simple hand-held device. This device has broad potential for use in gastroenterology including ablation of superficial epithelium, debulking of large tumors and hemostasis.     

Epidemiology of sleep-related obstructive breathing

The diagnosis of obstructive sleep apnoea syndrome (OSAS) and upper airway resistance syndrome (UARS) is based both on a combination of laboratory findings from whole-night sleep recordings and daytime symptoms. Due to the recent interest in breathing disturbances during sleep many prevalence studies have been performed within this field. There are, however, methodological difficulties in characterizing these syndromes in large populations; many of the studies have therefore been unable to present an overview of the complete syndromes but rather have focused on specific characteristics. In epidemiological research snoring and/or daytime sleepiness have often been used as markers of OSAS, while other studies have looked only on the respiratory disturbances or oxygen desaturation. Studies on the prevalence of OSAS based on polysomnography are reviewed here, as well as investigations where associated factors such as cardiovascular diseases and mortality were analysed. The interrelationships between snoring, daytime symptoms and laboratory findings are discussed. Gender, age, obesity, smoking, alcohol and ethnicity are all factors that influence the prevalence of OSAS. The data on associations between OSAS and cardiovascular disease or mortality are sometimes unrelated. Much of the discrepancy between different studies can be explained by the methodological difficulties connected with the definition of OSAS and also by the fact that the association between sleep-disordered breathing and cardiovascular outcome seems to be age-dependent.