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V Pittoni

Publications and source records attributed to V Pittoni.

28 records · Page 2Linked to original sources
PubMed1996

Anticardiolipin and anti-beta 2-GPI are two distinct populations of autoantibodies.

This study has been undertaken to assess whether anticardiolipin and anti-beta 2-GPI are two distinct populations of (auto)antibodies, and to clarify whether the beta 2-GPI region critical for phospholipid binding is also crucial for anti-beta 2-GPI reactivity. Fourteen of the 62 anticardiolipin (aCL) ELISA positive sera (22.6%) were positive for anti-beta 2-GPI by immunoblotting, 42 (67.7%) for aCL using TLC immunostaining. IgG fractions from 5 sera gave the same anticardiolipin reactivity detected by TLC immunostaining in the corresponding sera. All anti-beta 2-GPI-positive sera were reactive with the phenylthiocarbamyl derivative of the protein, indicating that binding of phenylisothiocyanate with lysine residues does not modify the molecule antigenicity. In addition, incubation of IgG fractions with the phospholipid binding site did not modify reactivity with beta 2-GPI. These findings demonstrate that: a) "true" antiphospholipid antibodies are detectable in patients' sera; b) aCL and anti-beta 2-GPI have a different immunological profile; c) the beta 2-GPI phospholipid-binding site is not the region recognized by the antibodies.

Adult↗
PubMed1995

Plasma endothelin-1 levels, pulmonary hypertension, and lung fibrosis in patients with systemic sclerosis.

PURPOSE: To investigate the behavior of circulating endothelin (ET)-1 concentrations in patients affected by systemic sclerosis, and to elucidate the possible relationships existing in this disease among plasma peptide levels, pulmonary hypertension, and lung fibrosis. PATIENTS AND METHODS: Circulating ET-1 levels were determined by reverse-phase, high-pressure liquid chromatography followed by sensitive radioimmunoassay in 20 patients affected by systemic sclerosis (18 women and 2 men, mean age 48.1 +/- 13.7 years) with or without pulmonary hypertension as evaluated by Doppler echocardiography, or lung fibrosis as measured by a score method based on lung examination by high-resolution computed tomography (HRCT). A group of 18 normal volunteers served as controls (15 women and 3 men, mean age 45.0 +/- 10.1 years). RESULTS: Plasma ET-1 levels were significantly higher (P < 0.001) in patients with systemic sclerosis (1.72 +/- 0.28 pg/mL) than in control subjects (0.63 +/- 0.06 pg/mL). Pulmonary artery systolic hypertension was detected in 10 patients (50%) with systemic sclerosis (56.2 +/- 18.0 mm Hg, range 37 to 97) versus none of the control subjects (30.2 +/- 2.2 mm Hg, P < 0.0001). Lung fibrosis was present in 12 patients (60%), with an HRCT overall score of 9.0 +/- 4.6. There were no significant differences in plasma ET-1 levels between patients with pulmonary hypertension (1.58 +/- 0.20 pg/mL) or without it (1.76 +/- 0.39 pg/mL, P = 0.188, not significant [NS]); or between patients with lung fibrosis (1.65 +/- 0.14 pg/mL) or without fibrosis (1.78 +/- 0.37 pg/mL, P = 0.290, NS). In particular, 6 patients had neither pulmonary hypertension nor lung fibrosis. In these patients, plasma ET-1 levels were similar compared with the others (1.85 +/- 0.49 versus 1.66 +/- 0.13, respectively; P = 0.180, NS). No correlations were observed between ET-1 levels and either pulmonary pressure levels or HRCT overall scores. CONCLUSIONS: The use of a sensitive assay, highly selective for ET-1, showed higher levels of circulating peptide in patients affected by systemic sclerosis than in control subjects. Neither pulmonary hypertension nor lung fibrosis was accompanied by a further rise in plasma ET-1 concentrations.

Adult↗
PubMed1995

Insulin stimulates endothelin-1 secretion from human endothelial cells and modulates its circulating levels in vivo.

Endothelin-1 (ET-1) is a potent vasoactive and mitogenic peptide produced by the vascular endothelium. In this study, we evaluated whether insulin stimulates ET-1 secretion by human endothelial cells derived from umbilical cord veins and by human permanent endothelial hybrid cells Ea.hy 926. Moreover, to provide evidence that insulin may stimulate ET-1 secretion in vivo, plasma ET-1 levels were evaluated in 7 type II diabetic normotensive males (mean age, 54.3 +/- 4.0 yr) during 2-h hyperinsulinemic euglycemic clamps (287 pmol insulin/m2.min-1) as well as in 12 obese hypertensive males (mean age, 44.2 +/- 4.6 yr) before and after a 12-week period of caloric restriction. Our results showed that insulin stimulated ET-1 release from cultured endothelial cells in a dose-dependent fashion. ET-1 release persisted for 24 h and was also observed at physiological insulin concentrations (10(-9) mol/L). The insulin-induced ET-1 secretion was inhibited by genistein, a tyrosine kinase inhibitor, and by cycloheximide, a protein synthesis inhibitor, suggesting that it requires de novo protein synthesis rather than ET-1 release from intracellular stores. In the in vivo experiments, plasma ET-1 levels rapidly increased during euglycemic hyperinsulinemic clamps (from 0.76 +/- 0.18 pg/mL at time zero to 1.65 +/- 0.21 pg/mL at 60 min; P < 0.05) and persisted elevated until the end of insulin infusion (1.37 +/- 0.37 pg/mL at 120 min; P < 0.05 vs. time zero). In obese hypertensives, plasma ET-1 levels significantly decreased after 12 weeks of caloric restriction (from 0.85 +/- 0.51 to 0.48 +/- 0.28 pg/mL; P < 0.04). The decrease in body weight induced by caloric restriction was accompanied by a significant reduction in fasting insulin levels (from 167.2 +/- 94.0 to 98.9 +/- 44.9 pmol/L; P < 0.05) which correlated with the reduction in plasma ET-1 levels (r = 0.78; P < 0.003). In conclusion, our data show that insulin stimulates both in vitro and in vivo ET-1 secretion. Such interaction could play a significant role in the development of atherosclerotic lesions in hyperinsulinemic conditions.

Adult↗
PubMed1994

Detection of antiphospholipid antibodies by immunostaining on thin layer chromatography plates.

There is increasing interest in the role of antiphospholipid antibodies in the so-called 'antiphospholipid antibody syndrome' (APS). The two major methods currently employed for detecting the autoantibodies are the solid phase ELISA and the LAI test (inhibition of phospholipid dependent coagulation assay). In our study we have tested the possibility of detecting antiphospholipid antibodies by immunostaining on thin layer chromatography (TLC) plates, since this technique permits the use of pure phospholipid molecules as antigen. Sera were collected from 20 patients with SLE without APS, 20 patients with APS, 20 anti-HIV positive subjects, ten patients with signs of APS but antiphospholipid negative (ELISA), 20 patients with syphilis and 40 matched blood donors. Results showed that only 72.3% of sera containing detectable levels of aCL antibodies in solid phase ELISA were also positive for aCL in TLC immunostaining; these discrepancies may be due to the presence of antibodies reacting with a protein complexed with phospholipid (beta 2-glycoprotein-I) or, alternatively, to the different antigenic presentation of phospholipids on chromatograms compared to the surface of microtitre wells. Furthermore, aCL monoclonal antibody CAL-3, as well as nine sera positive for aCL, also reacted with PS and PE. Previous absorption of these sera with CL micelles completely abolished the reactivity with PS and PE, demonstrating cross-reactivity among these three phospholipids. In conclusion, our findings reveal that TLC immunostaining is more specific, but less sensitive, than ELISA for the detection of antiphospholipid antibodies in human sera.

Antibodies, Anticardiolipin↗
PubMedDate not supplied

Specificity of antinuclear and antiphospholipid antibodies in sera of patients with autoimmune lymphoproliferative disease (ALD).

OBJECTIVE: A human lymphoproliferative syndrome characterized by a defect of the Fas-mediated apoptosis pathway in the absence of a fas gene mutation (Autoimmune Lymphoproliferative Disease) has recently been described and characterized by autoimmune phenomena. The aim of this study was to investigate the presence of antinuclear and antiphospholipid antibodies and to define their specificity in 5 pediatric patients with this syndrome. METHODS: Antinuclear antibodies were investigated by Western Blot and IIF performed under standard as well as apoptotic conditions. The fine specificity of antiphospholipid antibodies was dissected by an ELISA for anti-beta 2-glycoprotein I, anti-prothrombin, anti-annexin V and anti-protein S antibodies, and by immunostaining on thin layer chromatography plates for antiphospholipid molecule antibodies. RESULTS: This study showed that the autoantibodies found in these patients targeted a broad spectrum of nuclear antigens which undergo redistribution from the nucleus to the cytoplasm and plasma membrane during the course of the apoptotic process. This reactivity does not comprise known specificities such as anti-extractable nuclear antigens or anti-dsDNA. Antiphospholipid antibodies were also found in these sera. A further characterization of the antiphospholipid antibodies showed the presence of a heterogeneous response with antibodies directed to negatively-charged phospholipids and antibodies targeting coagulation-related proteins (beta 2-GPI, prothrombin, annexin V) which are considered relevant antigens in the antiphospholipid syndrome. CONCLUSIONS: These results suggest that lack of tolerance due to a defect of Fas-mediated apoptosis allows the survival of B and T clones involved in the antinuclear and antiphospholipid immune responses.

Adolescent↗
PubMedDate not supplied

Anti-cardiolipin antibodies in HIV infection are true antiphospholipids not associated with antiphospholipid syndrome.

The aim of the present study was to evaluate the fine specificity of anticardiolipin (aCL) antibodies detectable in the sera of patients with HIV infection. aCL are generally associated with thrombotic events in autoimmune diseases. A solid phase ELISA which discriminates between aCL binding to phospholipids and aCL binding to phospholipid/beta 2-glycoprotein I (cofactor) complex was employed. Thirty-nine HIV and 20 aCL positive systemic lupus erythematosus (SLE) sera were examined. In HIV sera, reduced binding to phospholipid was seen if cofactor was added. On the contrary, in SLE-sera the cofactor improved aCL binding. No thrombotic events were recorded in HIV infected subjects presenting with aCL. Thus, aCL in HIV infection and in SLE appear to have different specificities. In HIV infection the true epitope of aCL is likely to be on the phospholipid component only, whereas in SLE aCL seem directed against the cofactor/CL complex. Considering the anticoagulant role of beta 2-glycoprotein I, this observation might account for the lack of thrombosis in HIV patients with "true" aCL.

Antibodies, Anticardiolipin↗
PubMedDate not supplied

Decreased immunoreactive beta-endorphin in mononuclear leucocytes from patients with chronic fatigue syndrome.

OBJECTIVE: To investigate beta-endorphin concentrations in the peripheral blood mononuclear cells (PBMC) of patients with chronic fatigue syndrome (CFS). METHODS: Sixteen patients with CFS were enrolled in this study. Ten healthy subjects were studied as controls. Beta-endorphin concentrations were measured in PBMC by radioimmunoassay performed with antibodies specific for the C-terminal portion of human beta-endorphin. RESULTS: Beta-endorphin concentrations in the PBMC of chronic fatigue patients were significantly lower (p < 0.001) than in healthy subjects (mean +/- SD: 8.5 +/- 7.0 vs. 42.6 +/- 22.6). CONCLUSION: Patients with CFS were found to have low levels of PBMC beta-endorphin. This finding may reflect the condition of chronic immune activation in CFS that has been reported in previous investigations. Beta-endorphin concentrations in PBMC seem to mirror the central nervous system homeostasis of the opioid. Therefore, we would postulate that the fatigue and weakness typical of CFS could be related to low beta-endorphin concentrations at the central nervous system level.

Adolescent↗