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Effects of Bordetella pertussis toxin pretreatment on the antiarrhythmic action of ischaemic preconditioning in anaesthetized rats.
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1. Bordetella pertussis toxin, which catalyses the ADP-ribosylation of certain guanine nucleotide binding proteins (G proteins), thus functionally uncoupling them from associated receptors, was examined to determine whether it modified the antiarrhythmic effect of ischaemic preconditioning in anaesthetized rats. 2. Pertussis toxin (25 micrograms kg-1, i.p., 48 h prior to heart isolation) attenuated the negative chronotropic effect of acetylcholine (ACh) in rat isolated Langendorff perfused hearts. ACh (10 microM) reduced heart rate by 4% in hearts taken from pertussis toxin-treated animals, compared to a reduction of 57% in hearts taken from animals treated only with vehicle. 3. In anaesthetized rats, ischaemic preconditioning (a single 3 min occlusion of the left main coronary artery followed by 10 min reperfusion) had a pronounced antiarrhythmic effect during a subsequent 30 min period of regional myocardial ischaemia. Compared to hearts receiving only a 30 min period of left coronary occlusion, there was a reduced mortality (67% and 0% for control and preconditioned groups, respectively; P < 0.01) and decreased incidences of ventricular tachycardia (VT) and ventricular fibrillation (VF). Pretreatment with pertussis toxin (25 micrograms kg-1, i.p., 48 h previously) did not modify the arrhythmias associated with a 30 min period of regional myocardial ischaemia, neither did it modify the reduction in mortality (from 56% to 0%; P < 0.05) associated with preconditioning. Furthermore, the decrease in total ventricular premature beat count induced by preconditioning seen in controls (from 427 +/- 130 to 95 +/- 45) was also seen in pertussis toxin-treated rats (from 252 +/- 190 to 57 +/- 25).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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The advantages of the new, safer, but more expensive iodinated contrast agents are discussed, and opinions on which patient groups should receive the agents are presented. 相似文献
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E. Rigotti G. L. Piacentini M. Ress R. Pigozzi A. L. Boner D. G. Peroni 《Clinical and experimental allergy》2006,36(5):614-618
BACKGROUND: Precise relationship between breastfeeding and infant allergy is poorly understood. Objective Aim was to quantify TGF-beta(1) and IL-10 in colostrum and mature milk from allergic and non-allergic mothers and to verify relationship with allergic disease development. METHODS: Mothers (13 allergics, nine controls) of 22 newborns participated to prospective study on development of children atopy. Colostrum and mature milk were assayed for TGF-beta(1) and IL-10 by ELISA. Children underwent paediatrician evaluation at 6 months of life. RESULTS: Data are presented as median values and range. A significant difference in concentration of TGF-beta(1) between colostrum (330, range 0-3400 pg/mL) and mature milk (215, range 0-2400 pg/mL) was observed in samples from allergic mothers (P=0.015). In mature milk TGF-beta(1) was significantly lower in allergic (215, range 0-2400 pg/mL) than in non-allergic mothers (1059, range 0-6250 pg/mL) (P=0.015). IL-10 was weakly expressed without significant differences between allergic (4.8, range 0-42 and 9.5, range 0-42 pg/mL in colostrum and in mature milk) and non-allergic mothers (0, range 0-42 pg/mL in colostrum and 0, range 0-42 pg/mL in mature milk). After 6 months 46% infants from allergic mothers, but none from controls, presented atopic dermatitis. CONCLUSION: TGF-beta(1) was significantly less secreted in mature milk of allergic mothers, while no difference in IL-10 was found. Particular cytokine patterns in milk could influence development of atopic diseases. Further immunological studies in this field are necessary. 相似文献
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S. Matà S. Corzani R. Biagiotti S. Piacentini G. Siracusa M. G. Giudizi M. D. Mastio W. Borsini R. Taiuti A. Vultaggio S. Sorbi E. Maggi 《European journal of neurology》2007,14(10):1147-1153
Autoimmune mechanisms are postulated to play a role in the development and progression of dysimmune neuropathies (DN). We investigated the relation between lymphocyte number and marker expression, and disease activity in 20 patients with DN under intravenous immunoglobulins (IVIg) treatment. B- and T-lymphocyte markers were studied by flow cytometry of the expression of CD5, CD25, CD23 and CD38 markers on B cells and of CD3, CD4 and CD8 markers, respectively. These parameters were compared with those obtained from matched healthy volunteers. The proportions of CD38+ B cells were higher in patients compared with those of controls. Proportions of activated CD4+ and CD8+ T cells were comparable in peripheral blood mononuclear cells of patients and controls, but a significant reduction of the absolute numbers of CD3+, CD4+ and CD8+ cells were observed in DN patients. The percentages of CD25+ memory T cells were instead significantly increased in DN patients. Lastly, T-cell reduction and the CD19/CD38 ratio over total B (CD19+) cells directly correlated with a poor response to IVIg therapy. In DN, whereas T-cell number is reduced, activated T and B cells are increased, thus suggesting an intrinsic defect of the immune response. 相似文献
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A modified technique for catheterization of the pulmonary artery was developed. It involves the passage of a tapered, movable-core, J-tipped guide wire across the right ventricle into the pulmonary artery followed by the advancement of a straightened Grollman pigtail catheter. The technique was successful in 34 of 34 pulmonary artery catheterizations. The method avoids prolonged catheter manipulation within the right ventricle. In addition, since the catheter does not cross the tricuspid valve until the guide wire has been advanced, the occasional complication of the pigtail "hooking" on a tricuspid valve leaflet or chordae tendineae during catheter withdrawal and manipulation is prevented. 相似文献
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Identification of a salivary agglutinin-binding domain within cell surface adhesin P1 of Streptococcus mutans. 总被引:6,自引:16,他引:6
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DNA encoding the alanine-rich region (A-region) of the cell surface adhesin, P1, from Streptococcus mutans was subcloned and expressed as a fusion protein with the maltose-binding protein (MBP) of Escherichia coli. The A-region fusion protein was shown to competitively inhibit both adherence of S. mutans to salivary agglutinin-coated hydroxyapatite and fluid-phase agglutinin-mediated aggregation of this organism. MBP alone or an MBP-paramyosin fusion protein was not inhibitory. Proteolytic cleavage of the fusion protein into its component moieties, MBP and A-region, resulted in breakdown of the A-region into three main fragments. Western immunoblot analysis of calcium-dependent agglutinin binding to this preparation revealed binding specificity for a 28-kDa fragment. Thus, the A-region of P1 is an important domain which interacts directly with salivary agglutinin, and this interaction interferes with both the aggregation and the adherence mechanisms in vitro. 相似文献