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S Paoletti

Publications and source records attributed to S Paoletti.

67 records · Page 4Linked to original sources
PubMed1989

Polyelectrolytic effects in semi-flexible carboxylate polysaccharides. Part 2.

A statistical model is presented in which an ionic polymer is taken as a linear arrangement of flexible segments (similar to the spring-bead model). This model is used to represent semi-flexible linear ionic polysaccharides in solution. The distribution of end-to-end distances is taken from Monte Carlo calculations of the amylosic chain conformation and combined with Manning's counterion condensation theory of linear polyelectrolytes. The excess thermodynamic properties are then calculated as a function of the degree of ionization and of a number of physical variables. The results show that the statistical average of thermodynamic functions taken over the conformational states is not equivalent to the thermodynamic function of the average conformation. This has important implications for the correct comparison of theoretical prediction with the experimental results.

Carbohydrate Conformation↗
PubMed1989

Conformational transition of poly(alpha-L-glutamic acid). A polyelectrolytic approach.

The charge-induced conformational transition of poly(alpha-L-glutamic acid) (PLGA) is considered in this paper from the point of view of proton dissociation. Equations for the excess electrostatic Gibbs energy of dissociation (i.e., delta pKa) are derived as a function of the degree of ionization, alpha. These analytical equations are used to describe some experimental dissociation curves at different polymer and salt concentrations. The dependence of the calculated delta pKa with respect to the ionic strength for the two conformational states, alpha-helical and extended coil, respectively, is rather satisfactorily explained. Even more interesting are the predictions which are derived from this approach for the transition point, alpha tr which is found to be ionic-strength dependent, in full agreement with the experimental results.

Kinetics↗
PubMed1987

[The blood coagulation system in progressive systemic scleroderma].

Twenty-five scleroderma patients have been studied to evaluate blood coagulative and fibrinolytic parameters. An increase in FVIII related activities and a reduction in fibrinolytic activity was observed. These changes may be related to the endothelial damage present scleroderma patients I the consequent "in loco" activation of blood coagulation may cause the microthrombosis that is very often observed in the earliest phases of the disease.

Adult↗
PubMed1987

Pulmonary involvement in progressive systemic sclerosis: a multidisciplinary approach.

In an attempt to define the early features and the natural evolution of lung involvement in progressive systemic sclerosis (PSS), we planned a multidisciplinary study of these patients using radiological, scintigraphic and functional methods. As yet we have studied 21 subjects, all affected by PSS according to the American Rheumatism Association criteria. A well-defined restrictive functional pattern was present only in 10 patients out of 21; an increased elastic recoil may be present before a significant decrease of the transfer test for carbon monoxide; an increased alveolar-capillary permeability assessed by the 99mTc-diethylene-triamine-pentacetic acid (99mTc-DTPA) clearance rate has been detected in almost all the patients (13 out of 14) in at least one lung field; no significant correlation has been found between the radiological lung involvement and the 99mTc-DTPA clearance rate. We think that these preliminary results are consistent with an alveolar and interstitial inflammation rather than with a vasculitic process.

Adult↗
PubMed1985

Serum beta 2-microglobulin in systemic sclerosis.

The role of beta 2 microglobulin (beta 2-m) in Systemic Sclerosis (SS) has been evaluated. Twenty-four female patients have been examined: 15 of them were affected by acrosclerosis (Group 1) and 9 of them by diffuse sclerosis (Group 2). 46.6% of Group 1 and 44.4% of Group 2 had values significantly higher than normal controls. (P less than 0.01 and P less than 0.005 respectively). The authors deal with the validity of the use of B2-m as index of inflammatory activity of the disease.

Adult↗
PubMed1981

Influence of serum albumins on decomposition rates of para-substituted 1-phenyl-3-methyltriazenes and 5-(3-methyl-1-triazeno)imidazole-4-carboxamide in near physiological conditions.

The influence of human serum albumin on the decomposition rates of some arylmonomethyltriazenes in buffered aqueous solution was investigated. From the experimental data, a model for the triazene-albumin interaction was derived, and the thermodynamic parameters were systematically calculated by two independent methods. The results show marked dependence of the energetics of binding on the substituent in the triazene aromatic ring. For most of the triazenes studied, the binding with albumin was mainly enthalpy driven. Measurements also were performed using bovine and murine serum albumins.

Alkylating Agents↗
PubMedDate not supplied

Proton MR spectroscopy in quantitative in vivo determination of fat content in human liver steatosis.

To demonstrate that the lipid volume fraction in liver steatosis can be accurately estimated with in vivo hydrogen-1 magnetic resonance (MR) spectroscopy, the authors developed a calibration procedure based on in vitro MR spectroscopy of lipid extracts from steatotic liver specimens. The lipid volume fractions determined with the calibration procedure were compared with the results of histomorphometry and with calibrated computed tomographic (CT) data. The volume fraction of fat determined with MR spectroscopy was in good agreement with the CT results, whereas histomorphometry underestimated the amount of hepatic fat. The results indicate that determination of the fat volume fraction in steatotic liver can be achieved noninvasively with MR spectroscopy.

Adult↗
PubMedDate not supplied

[Anti-cytokine therapy: present status and future perspectives in nephrology].

The increasing understanding of the role of cytokines in chronic inflammatory disease, autoimmunity and neoplastic disease has led to a new generation of therapeutic agents, the anti-cytokine blocking agents. In this article, we review current knowledge of two different available approaches: the use of Thalidomide and the anti-cytokine antibody immune therapy. Thalidomide is an immunodulatory and antiangiogenic drug; the most pronounced effect of this drug is the inhibition of tumor necrosis factor-alpha (TNF-alpha ) production. A few years after its withdrawal from the European and Canadian markets due to severe teratogenic effects, the unexpected activity of Thalidomide in reactive lepromatous leprosy stimulated further study. After some confirmatory placebo-controlled trials, multiple researches are now in progress to evaluate the optimal dose of Thalidomide in several autoimmune and neoplastic diseases. Both passive and active immunization can safely, transiently and effectively be used, as documented by animal experimentation and confirmed by clinical trials. Novel anti-cytokine therapeutic compounds, based on passive antibody immunization, are now available to treat rheumatoid arthritis and have been shown to help in Crohn's disease and in several other autoimmune diseases, and to control neoangiogenesis in cancer patients. The durability of the benefit, safety and pharmacoeconomic issues will determine whether this early success will prove to be a major breakthrough in the treatment of these painful and incurable diseases and eventually of other chronic inflammatory conditions in uremic patients.

Cytokines↗
PubMedDate not supplied

An evaluation of some inflammatory, coagulative and immune factors in progressive systemic sclerosis.

Thirty-five patients affected by Progressive System Sclerosis (PSS) (20 acrosclerosis and 15 diffuse sclerosis) were subjected to the following laboratory tests: Beta 2 microglobulin (B2m), Fibronectin, C3c, C4, Fibrinogen, Factor VIII Coagulant (F. VIII:C), Factor VIII related Antigen (F. VIII:Ag), IgG, ESR, Antithrombin III (AT III), alpha 1 Antitrypsin (alpha 1AT) and alpha 2 Macroglobulin (alpha 2M). The results showed that no difference was observed between the normal group and the groups of PSS patients with respect to alpha 1AT, alpha 2M, and AT III. In contrast the B2m, ESR, IgG, F. VIII:Ag results were significantly higher in the PSS patients, while Fibrinogen and C3c results were slightly higher, but no high enough to be of statistical significance. The two PSS patient subgroups did not produce significant results, only the C4 values were lower in the Diffuse Sclerosis subgroup. From these results it seem that the tests used are not very useful indifferentiating the two subgroups of the PSS patients.

Adult↗
PubMedDate not supplied

Factor VIII complex in progressive systemic sclerosis.

Factor VIII complex and its related activities (Coagulant, Antigen and Ristocetin Cofactor) have been investigated in 23 patients with Progressive Systemic Sclerosis (PSS) divided into two groups: acrosclerosis and diffuse sclerosis. All Factor VIII-related activities were higher in PSS patients than in normal subjects. No difference in F. VIII-related Antigen (F. VIIIR:Ag), F. VIII-related Ristocetin Cofactor (F. VIIIR:Co) and F. VIII Coagulant activity (F. VIII:C) was found comparing the patient groups. F. VIII:C was increased significantly less than F. VIIIR:Ag and F. VIIIR:Co in both patient groups. Some hypotheses about the pathogenesis of this increase are discussed.

Adult↗