Despite some evidence of effectiveness of specific regimens, the relevance of these findings is limited by the modest survival benefit and the lack of evaluation of the quality-of-life impact of these treatments.

6 Dannaeus A, Inganaes M. A follow-up study of children with food allergy.Clinical course in relation to serum IgE and IgG antibody levels to milk, egg and fish. Clin Allergy 1981;11:533-9. 7 Host A, Halken S, Jacobsen HP, Estmann A, Mortensen S, Mygil S. The natural course of cow's milk protein allergy/intolerance (abstract One hypothesis which may explain why some children grow out of their peanut allergy lies in the physical structure of the peanut proteins. If the protein is visualised as a string of amino acid beads scrunched up into a 3-dimensional ball there are two ways an antibody can bind to that structure. Firstly, an antibody can bind to a specific antigen by attaching itself to sequential amino acid beads in the protein. These sections of the protein are known as linear epitopes. Alternatively, an antibody binds to a section which is effectively folded up so that it not only binds to a number of amino acid beads in one part of the protein string but also to beads in other sections of the string. These antigenic binding sites are known as conformational epitopes.Research in other food allergies suggests that children who develop tolerance to peanuts may have peanut specific IgE which binds much more to conformational peanut epitopes (which are generally more labile and easily destroyed by heat) and that children who remain reactive to peanuts have IgE which binds mostly to linear epitopes (which are very stable). As the gut matures with age more linear epitopes than conformational epitopes pass through the gut wall. So if the hypothesis is found to be true this could explain why some people continue to react to peanuts and others seemingly outgrow their allergy.Such differences in IgE binding have already been observed in children with egg or cows' milk allergy. An interesting question is why up to 50% of children with egg or cows' milk allergy outgrow the allergy while only about 10% seem to develop tolerance to peanuts. Abi Berger, science editor, BMJ Effectiveness of antibiotic prophylaxis in critically ill adult patients: systematic review of randomised controlled trialsRoberto D'Amico, Silvia Pifferi, Cinzia Leonetti, Valter Torri, Angelo Tinazzi, Alessandro Liberati on behalf of the study investigators AbstractObjective: To determine whether antibiotic prophylaxis reduces respiratory tract infections and overall mortality in unselected critically ill adult patients. Design: Meta-analysis of randomised controlled trials from 1984 and 1996 that compared different forms of antibiotic prophylaxis used to reduce respiratory tract infections and mortality with aggregate data and, in a subset of trials, data from individual patients. Subjects: Unselected critically ill adult patients; 5727 patients for aggregate data meta-analysis, 4343 for confirmatory meta-analysis with data from individual patients. Main outcome measures: Respiratory tract infections and total mortality. Results: Two categories of eligible trials were defined: topical plus systemic antibiotics versus no treatment and topical prepar...

Chemotherapy produces a small survival benefit in patients with curatively resected gastric cancer. However, taking into account the limitations of literature based meta-analyses, adjuvant chemotherapy is still to be considered as an investigational approach.

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Despite the fact that care provided by specialized centres/clinicians appeared to be better both when assessed in relation to process indicators and to mortality, this evidence should be considered far from conclusive because of major methodological flaws in these studies. Relative to current efforts to promote evidence-based policy-making, this review underscores the limited capability of scientific information to provide reliable guidelines for structuring better health care systems.