[Probiotics, prebiotics and zinc in the therapy and prevention of acute infectious diarrhoea in children: state of the art]. / Probiotici, prebiotici e zinco nella terapia e prevenzione della diarrea acuta infettiva in età pediatrica: qual' è l'attuale evidenza?

Selected probiotics (mainly Lactobacilli, and particularly LGG, and Saccharomyces boulardii) have recently demonstrated a therapeutic efficacy in acute diarrhoea, if used in the early phase of infection and at high concentration. Further data are needed to clarify their effect for prevention and travellers' diarrhoea. The mechanisms of action of probiotics need to be fully elucidated but seem to include a complex interaction of epithelial, molecular, metabolic and immune responses. There is an increasing evidence that different micro-organisms show different properties and efficacy. An accurate identification and selection of the strains, the dose and the patients are thus crucial for a correct therapeutic approach. Prebiotics can modify the intestinal flora and interact with the immune system of the host against specific pathogens. However, clinical trials are currently limited and a beneficial effect of prebiotics in acute diarrhoea is still lacking. In developing countries zinc supplementation demonstrated a significant reduction of fecal excretion, duration, severity and persistency of diarrhoea. Moreover, zinc may improve immune status, intestinal permeability, epithelial and enzymatic functions, and transport of electrolytes. The use of zinc in addition to oral rehydration solution (ORS) could thus theoretically improve the treatment and reduce the complications of diarrhoea worldwide. However, in developed countries, no trial using zinc supplementation in patients with acute diarrhoea has been published yet and the cost-benefit ratio of zinc supplementation needs to be assessed.

Tear histamine and histaminase during the early (EPR) and late (LPR) phases of the allergic reaction and the effects of lodoxamide.

The objectives of this study were two-fold: to identify tear histamine content and its relationship to changes in tear histaminase activity during the early (EPR) and late phases (LPR) of the allergic reaction induced by a conjunctival provocation test (CPT) and to evaluate the effects of lodoxamide on histamine release and allergic signs and symptoms during EPR and LPR. A baseline CPT was administered to 20 allergic patients with no baseline signs or symptoms of allergy. Clinical signs and symptoms were evaluated after 20 minutes and 6 hours. Tear samples were taken after 5-10 minutes and after 6 hours for subsequent analyses of cytology and histamine content (ELISA). Patients were then randomly assigned to receive lodoxamide or placebo four times daily for one week in a double-masked fashion. A second CPT was done after this therapy and the same parameters were re-evaluated. During EPR, tear histamine increased significantly with respect to baseline values (p < 0.05). During LPR, tear histamine increased significantly (p < 0.05) only in histamine inactivated samples. Histaminase enzymes were also significantly less active during the EPR (5.5 +/- 0.7) than the LPR (9.9 +/- 2.3) and at baseline. Histamine levels significantly correlated with allergic signs and symptoms (p < 0.05) only during the EPR. Lodoxamide significantly reduced histamine release during EPR (p < 0.05), allergic signs and symptoms during both EPR (p < 0.001) and LPR (p < 0.005), and tear cytology counts during LPR. In conclusion, greater histaminase activity may account for the smaller amount of tear histamine generally found during LPR, while these enzymes seem to play less of a role during the surge of histamine release and activity in the EPR. Lodoxamide was shown to ideally inhibit various aspects of the allergic reaction: clinical signs and symptoms in both the early and late phases, the primarily EPR-related peak of histamine release, and the primarily LPR-related changes in tear cytology.