Biomedical subjects
Publications and source records attributed to R Falchetti.
An assay is described for assessing the potency of thymic extracts by the capacity of guinea pig spleen lymphocytes to form rosettes with rabbit red blood cells. Its sensitivity and reproducibility have been evaluated by statistical analysis of the data obtained testing different batches of the calf thymus extract TP-1.
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The effect of ditazole, a new antiaggregant oxazole derivative as well as its possible interaction with urokinase on the formation of electrically induced thrombus, was assayed in rabbits. The activity of ditazole in reducing thrombus weight was comparable to that of aspirin. In the ditazole- or aspirin-treated animals, the microscopical examination of the thrombus showed a reduction in the fibrin component, and well-isolated platelets not undergoing a viscous metamorphosis were present. Urokinase, administered in combination with these antiaggregant drugs, did not induce a further reduction in thrombus weight. However, this additional treatment did induce clearly visible lytic areas and histological modifications as observed with the antiaggregant drugs. These data suggest that the antiplatelet drug ditazole may be an effective antithrombotic agent in man and could facilitate the penetration of urokinase into the thrombus.
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The effect of phosvitin (1 g kg(-1), i.p.) on ecg changes induced in rats by a reduction of partial oxygen pressure in the respiratory mixture was studied. Phosphocreatine, phosphoserine, ATP and Na2HPO42H2O were also administered intraperitoneally for comparison. Phosvitin alone was found to prevent the hypoxia-induced T-wave changes (flattening or disappearance), which were also temporarily aggravated by injection of noradrenaline. As to the metabolic, hypoxia-induced myocardial changes, two hypotheses are discussed: a release of phosvitin phosphate radicals ready for immediate utilization or a drug action mediated via a membrane-bound intrinsic proteinkinase system.
4,5-Diphenyl-2-bis(2-hydroxyethyl)aminoxazole (ditazole) 200 mg/kg administered orally for 3 days significantly reduced the one-stage prothrombin time in rats treated concomitantly with bishydroxycoumarin (BHC) or warfarin, orally or i.p., as compared with rats given only BHC or warfarin. No significant change occurred in heparin anticoagulant activity when it was administered to rats pretreated with ditazole for 3 days. Warfarin and BHC, in vitro or in vivo, did not influence platelet aggregation or the antiaggregating activity of ditazole. The co-administration of heparin and ditazole enhanced the antiaggregating activity of the two drugs in both in vivo and in vitro tests.
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MLBL is an oral immunostimulating vaccine consisting of bacterial standardized lysates obtained by mechanical lysis of different strains of Gram-positive and Gram-negative bacteria that can cause acute and chronic infections of the respiratory tract. Previous studies suggested a stimulating effect of MLBL both on humoral and cellular immune responses. In the present study, the in vitro effects of MLBL on human lymphocyte effector functions and its mechanisms of action were evaluated. The results show that the most remarkable effects of MLBL on the immune system are: i) activation of the IL-2 receptor (IL-2Ralpha) on different lymphocyte subsets (B, CD4+ T and CD8+ T cells) involved both in humoral and cellular immune responses; ii) induction of cytokine synthesis (IL-2, IL-10, IL-12, IFNgamma) in the immune competent cells that induce and regulate immune responses; iii) generation of CD4+ and CD8+ effector T cells. Overall, these results suggest that the therapeutic effect of MLBL on acute and recurrent infections of the respiratory tract is related to its ability to activate the responses of different subsets of immune competent cells both for humoral and cellular immunity. Moreover, these effects can be induced either by direct immune cell activation or through the generation and activation of immune effector cells.
The aim of the present study is to investigate in humans the mechanism by which the oral vaccine Polyvalent Mechanical Bacterial Lysate (PMBL) can rapidly mobilize specific immune response and evaluate the efficacy of its immunostimulating activity in preventing recurrent infections of the upper respiratory tract (URTIs) in a group of patients with a medical history of URTI recurrence. Patients received, by sublingual route, PBML, an immunostimulating lysate obtained by mechanical lysis of the most common bacteria responsible for upper respiratory tract infections. The treatment was administered for 10 consecutive days/month for 3 consecutive months. After the end of the treatment period the patients were followed up for an additional 3 months. The frequency of IgM memory B cells and the expression of the activation marker CD25 in peripheral blood lymphocytes were measured using the flow cytometric method before the start and at days 30 and 90 of the treatment cycle. To correlate clinical results to immunological parameters, the patients were monitored at different time-points during the treatment and at the end of follow-up period. The results showed that PMBL exerts a therapeutic and preventing effect in acute and recurrent infections of the upper respiratory tract and that this effect correlated with the activation and enhancement of both IgM memory B lymphocytes (CD24+/CD27+ cells) and IL2 receptor-expressing lymphocytes (CD25+ cells) involved either in humoral or cellular immunity.