Showing similarity of results given by two methods: a commentary.
Journal - Environmental pollution (Barking, Essex : 1987) (England )
There is a frequent need in the environmental sciences to show the similarity of the results given by two analytical methods. This cannot, however, be done within the conventional 'there is a difference' statistical hypothesis setting of, among others, Student's t-test. We demonstrate here a more appropriate approach that originates from drug testing and that can be applied with standard statistical software. It is a challenging approach, as it requires quantification of the similarity limit. If no pre-determined value is given for similarity, a potential data-supported similarity limit can be explored from the data. The approach has numerous other potential application areas, e.g. parallelism of regression slopes, homogeneity of variances and lack of interaction.
|ISSN : ||0269-7491|
|Mesh Heading : ||Ecology Models, Statistical Software Therapeutic Equivalency|
|Mesh Heading Relevant : ||Data Interpretation, Statistical methods|
Food allergy alters jejunal circular muscle contractility and induces local inflammatory cytokine expression in a mouse model
Journal - BMC Gastroenterology
BackgroundWe hypothesized that food allergy causes a state of non-specific jejunal dysmotility. This was tested in a mouse model.MethodsBalb/c mice were epicutaneously sensitized with ovalbumin and challenged with 10 intragastric ovalbumin administrations every second day. Smooth muscle contractility of isolated circular jejunal sections was studied in organ bath with increasing concentrations of carbamylcholine chloride (carbachol). Smooth muscle layer thickness and mast cell protease-1 (MMCP-1) positive cell density were assayed histologically. Serum MMCP-1 and immunoglobulins were quantified by ELISA, and mRNA expressions of IFN-?, IL-4, IL-6 and TGFß-1 from jejunal and ileal tissue segments were analyzed with quantitative real-time PCR.ResultsOvalbumin-specific serum IgE correlated with jejunal MMCP-1+ cell density. In the allergic mice, higher concentrations of carbachol were required to reach submaximal muscular stimulation, particularly in preparations derived from mice with diarrhoea. Decreased sensitivity to carbachol was associated with increased expression of IL-4 and IL-6 mRNA in jejunum. Smooth muscle layer thickness, as well as mRNA of IFN-? and TGF-ß1 remained unchanged.ConclusionIn this mouse model of food allergy, we demonstrated a decreased response to a muscarinic agonist, and increased levels of proinflammatory IL-6 and Th2-related IL-4, but not Th1-related IFN-? mRNAs in jejunum. IgE levels in serum correlated with the number of jejunal MMCP-1+ cells, and predicted diarrhoea. Overall, these changes may reflect a protective mechanism of the gut in food allergy.