Fluorescence in situ hybridisation in Carnoy's fixed tonsil tissue.

Fluorescence in situ hybridisation (FISH) is a powerful molecular technique that enables direct visualisation of specific bacterial species. Few studies have established FISH protocols for tonsil tissue in Carnoy's fixative, accordingly limiting its application to investigate the pathogenesis of tonsillar hyperplasia. Tonsil tissue from 24 children undergoing tonsillectomy for either recurrent tonsillitis or sleep-disordered breathing were obtained during a previous study. The specificity of each of the five FISH probes (Fusobacterium spp., Bacteroides spp., Streptococcus spp., Haemophilus influenzae and Pseudomonas spp.) were successfully optimised using pure and mixed bacterial isolates, and in Carnoy's fixed tonsil tissue. Bacteroides spp. were present in 100% of patients with microcolonies. In comparison, the prevalence of Fusobacterium spp. was 93.8%, Streptococcus spp. 85.7%, H. influenzae 82.35% and Pseudomonas spp. 76.5%. Notable differences in the organisation of bacterial taxa within a single microcolony were also observed. This is the first study to establish a robust FISH protocol identifying multiple aerobic and anaerobic bacteria in Carnoy's fixed tonsil tissue. This protocol provides a strong foundation for combining histological and microbiological analyses of Carnoy's fixed tonsil samples. It may also have important implications on the analysis of microorganisms in other human tissues prepared using the same techniques.

Physical characteristics of commercial and home-made nasal lavage solutions.

INTRODUCTION: Nasal saline lavage forms a cornerstone of chronic rhinosinusitis management. A number of saline lavage recipes and products are currently available but little is known of their relative physical characteristics. AIMS: To determine the osmolarity and pH of nasal lavage solutions, both commercial preparations and home-made recipes, and to determine the reproducibility of saline solution preparation. METHODS: Five home-made recipes and two commercial products were prepared in triplicate and analysed. Eight consecutive clinic patients prepared a commercial product and 11 prepared a home-made recipe, and the osmolarity and pH were measured. RESULTS: The osmolarity of the solutions varied widely, from 140 to 788 mmol/l and the pH varied from 7.88 to 8.50. The commercial and home-made solutions had similar reproducibility when prepared by patients. CONCLUSION: Some recipes were markedly hypo-osmolar and some were hyper-osmolar. All were slightly alkaline. The home-made recipes had similar physical characteristics and reproducibility to commercial preparations.