Showing papers by "University of Palermo published in 1997"

Potential Involvement of Fas and Its Ligand in the Pathogenesis of Hashimoto's Thyroiditis

Abstract: The mechanisms responsible for thyrocyte destruction in Hashimoto's thyroiditis (HT) are poorly understood Thyrocytes from HT glands, but not from nonautoimmune thyroids, expressed Fas Interleukin-1beta (IL-1beta), abundantly produced in HT glands, induced Fas expression in normal thyrocytes, and cross-linking of Fas resulted in massive thyrocyte apoptosis The ligand for Fas (FasL) was shown to be constitutively expressed both in normal and HT thyrocytes and was able to kill Fas-sensitive targets Exposure to IL-1beta induced thyrocyte apoptosis, which was prevented by antibodies that block Fas, suggesting that IL-1beta-induced Fas expression serves as a limiting factor for thyrocyte destruction Thus, Fas-FasL interactions among HT thyrocytes may contribute to clinical hypothyroidism

Factor V Leiden is associated with repeated and recurrent unexplained fetal losses

Abstract: Activated protein C resistance (APCR) is responsible for most cases of familial thrombosis. The factor V missense mutation Arg506 > Gln (FV Leiden) has been recognized as the commonest cause of this condition. Recently, it has been suggested that APCR is associated with second trimester fetal loss. We investigated the distribution of FV Leiden in a sample (n = 43) of Caucasian women with a history of two or more unexplained fetal losses. A group (n = 118) of parous women with uneventful pregnancies from the same ethnical background served as control. We found the mutation in 7 cases (16.28%) and 5 controls (4.24%; p = 0.011). A statistically significant difference between women with only early fetal loss vs those with late events (p = 0.04) was observed. Our data demonstrate a strong association between FV Leiden and fetal loss. Furthermore, they indicate that late events are more common in these patients.

Factor V Leiden, C>T MTHFR Polymorphism and Genetic Susceptibility to Preeclampsia

Abstract: We performed a case-controlled study to investigate whether the FV Leiden mutation and the C>T677 polymorphism of the 5,10 methylene tetrahydrofolate reductase (MTHFR) are associated with the occurrence of preeclampsia in 96 otherwise healthy preeclamptic women and 129 parous women as controls FV Leiden carriers were 10 (105%) in cases and 3 (23%) in controls (OR: 49, 95% Cl: 13-183) MTHFR TT homozygotes were 28 (298%) in cases and 24 (186%) in the control group (OR: 18,95% Cl 10-35) No difference in any of the polymorphisms was found between proteinuric (n = 45) and non-proteinur-ic (n = 51) patients Moreover, MTHFR polymorphism does not affect the association between FV Leiden and preeclampsia In conclusion, FV Leiden mutation and MTHFR TT genotype are associated with the occurrence of preeclampsia, suggesting that, during pregnancy, women carrying these gene variants are prone to develop such a complication

DNA Rereplication in the Presence of Mitotic Spindle Inhibitors in Human and Mouse Fibroblasts Lacking either p53 or pRb Function

Abstract: Cell cycle checkpoints are biochemical signal transduction pathways that prevent downstream events from being initiated until upstream processes are completed. We analyzed whether the p53 or pRb tumor suppressors are involved in a checkpoint(s) that prevents DNA rereplication in the presence of drugs that interfere with spindle assembly. Normal mouse and human fibroblasts arrested with a 4N DNA content when treated with nocodazole and Colcemid, whereas isogeneic p53-deficient or pRb-deficient derivatives became polyploid. Flow cytometric and cytogenetic analyses demonstrated that the polyploidy resulted from genome-wide rereplication without an intervening mitosis. Thus, p53 and pRb help maintain normal cell ploidy by preventing DNA rereplication prior to mitotic division.

Semiempirical Correlation between Optical Band Gap Values of Oxides and the Difference of Electronegativity of the Elements. Its Importance for a Quantitative Use of Photocurrent Spectroscopy in Corrosion Studies

Abstract: A semiempirical correlation between the optical band gap of binary oxides and the difference of electronegativity between the oxygen and metallic elements (Pauling's extraionic energy) is proposed. In the frame of the proposed correlation an estimate of the repulsive term in the total lattice energy of ionic oxides is obtained in very good agreement with the existing data. An extension of the correlation to the ternary oxides and hydroxides is proposed by using the concept of average cationic or anionic group electronegativity. The usefulness of the proposed correlation for the in situ characterization of passive films on metals and alloys by photocurrent spectroscopy is illustrated by reporting some preliminary experimental results on Sn and AlTi alloy.

Zero-Energy Rotating Accretion Flows near a Black Hole

Abstract: We characterize the nature of thin, axisymmetric, inviscid accretion flows of cold adiabatic gas with zero specific energy in the vicinity of a black hole by the specific angular momentum. Using two-dimensional hydrodynamic simulations in cylindrical geometry, we present various regimes in which the accretion flows behave distinctly differently. When the flow has a small angular momentum (λ λb), most of the material is accreted into the black hole, forming a quasi-spherical flow or a simple disklike structure around it. When the flow has a large angular momentum (typically, larger than the marginally bound value, λ λmb), almost no accretion into the black hole occurs. Instead, the flow produces a stable standing shock with one or more vortices behind it and is deflected away at the shock as a conical, outgoing wind of higher entropy. If the flow has an angular momentum somewhat smaller than λmb (λu λ λmb), a fraction (typically 5%-10%) of the incoming material is accreted into the black hole, but the flow structure formed is similar to that for λ λmb. Some of the deflected material is accreted back into the black hole while the rest is blown away as an outgoing wind. These two cases with λ λu correspond those studied in the previous works by Molteni, Lanzafame, & Chakrabarti and Ryu et al. However, the flow with angular momentum close to the marginally stable value (λms) is found to be unstable. More specifically, if λb λ ~ λms λu, the flow displays a distinct periodicity in the sense that the inner part of the disk is built and destroyed regularly. The period is roughly equal to (4-6) × 103Rg/c, depending on the angular momentum of the flow. In this case, the internal energy of the flow around the black hole becomes maximum when the structure with the accretion shock and vortices is fully developed. But the mass accretion rate into the black hole reaches a maximum value when the structure collapses. Averaged over periods, more than half the incoming material is accreted into the black hole. We suggest the physical origin of these separate regimes from a global perspective. Then we discuss the possible relevance of the instability work to quasi-periodic oscillations.

Potassic and Sodic Igneous Rocks from Eastern Paraguay: their Origin from the Lithospheric Mantle and Genetic Relationships with the Associated Parana flood tholeiites

Abstract: 3 DIPARTIMENTO DI SCIENZE DELLA TERRA, UNIVERSITY OF TRIESTE, VIA E. WEISS 8, I-34127 TRIESTE, ITALY 4 INSTITUTO DE GEOCIENCIAS, UNIVERSIDADE DE SAO PAULO, C.P. 30627, 01051 SAO PAULO, SP, BRAZIL 5 DIPARTIMENTO DI SCIENZE DELLA TERRA, ‘LA SAPIENZA’ UNIVERSITY, PIAZZALE ALDO MORO 5, I-00185, ROME, ITALY 6 ISTITUTO DI MINERALOGIA, PETROGRAFIA E GEOCHIMICA, UNIVERSITY OF PALERMO, VIA ARCHIRAFI 36, I-90100,

Stock market dynamics and turbulence: parallel analysis of fluctuation phenomena

Abstract: We report analogies and differences between the fluctuations in an economic index and the fluctuations in velocity of a fluid in a fully turbulent state. Specifically, we systematically compare (i) the statistical properties of the S&P 500 cash index recorded during the period January 84–December 89 with (ii) the statistical properties of the velocity of turbulent air measured in the atmospheric surface layer about 6 m above a wheat canopy in the Connecticut Agricultural Research Station. We find non-Gaussian statistics, and intermittency, for both processes (i) and (ii) but the deviation from a Gaussian probability density function are different for stock market dynamics and turbulence.

Characterization of Bacillus thuringiensis isolated from infections in burn wounds

Abstract: Four strains of Bacillus thuringiensis were isolated from infections in burn wounds and from water used in the treatment of burn wounds. The strains produced large parasporal inclusion bodies composed of 141, 83, and 81 kDa protoxins. The four strains were tested for insecticidal activity against larvae of Pieris brassicae and Aedes aegypti but showed no activity; Vero cell assays for the production of enterotoxins were also negative. Attempts to classify the strains according to flagellar H-serotype showed them all to be non-flagellated. Apart from two occupational health accidents that occurred during the handling of highly concentrated B. thuringiensis fluids, this is the first report of B. thuringiensis causing non-gastrointestinal clinical infection in immunosuppressed patients.

Automatic Video Database Indexing and Retrieval

Abstract: The increasing development of advanced multimedia applications requires new technologies for organizing and retrieving by content databases of still digital images or digital video sequences. To this aim image and image sequence contents must be described and adequately coded. In this paper we describe a system allowing content-based annotation and querying in video databases. No user action is required during the database population step. The system automatically splits a video into a sequence of shots, extracts a few representative frames (said r-frames) from each shot and computes r-frame descriptors based on color, texture and motion. Queries based on one or more features are possible. Very interesting results obtained during the severe tests the system was subjected to are reported and discussed.

In vitro antifungal properties of mouthrinses containing antimicrobial agents

Abstract: The purpose of this study was to investigate the in vitro antifungal properties of seven commercial mouthrinses containing antimicrobial agents. These included cetylpyridinium chloride (CPC), chlorhexidine digluconate (CHX), hexetidine (HEX), sanguinarine (SNG), and triclosan (TRN). The minimum fungicidal concentration (MFC) against six species of yeasts was determined by a broth macrodilution method. The kill-time of mouthrinses at half the concentration of the commercial formulations was also determined. MFCs were achieved with each mouthrinse, except the SNG-containing mouthrinse; against all the organisms being tested. However, the CPC-containing mouthrinse appeared more active than the other products (P < 0.001). There were no significant differences in MFC values among CHX mouthrinse products, once adjusted for initial concentration differences (P = 0.1). Kill-times of mouthrinses containing either CHX or CPC were less than or equal to 180 seconds with all the species of yeasts, and no significant d...

Intraperitoneal injection of tetracyclines protects mice from lethal endotoxemia downregulating inducible nitric oxide synthase in various organs and cytokine and nitrate secretion in blood.

Abstract: We have tested whether tetracyclines (TETs) are able to protect mice from lipopolysaccharide (LPS)-induced shock, a cytokine-mediated inflammatory reaction. Mice, injected with a single dose of tetracycline base (TETb; 1.5, 10 and 20 mg/kg of body weight) or doxycycline (DOXY; 1.5 mg/kg), were significantly protected from a lethal intraperitoneal injection of LPS (500 micrograms per mouse). TETs acted in early events triggered in response to LSP; in fact, they were no longer significantly protective if injected more than 1 h after the injection of endotoxin. LPS-treated mice protected by TETs showed a significant inhibition of tumor necrosis factor alpha (TNF-alpha), interleukin-1 alpha (IL-1 alpha), and nitrate secretion in the blood, events that were directly related with the survival. In mice treated with TETs a significant decrease of inducible nitric oxide synthase (iNOS) activity was observed in spleen and peritoneal cells compared with that detected in mice treated with LPS alone. Furthermore, TETs were found to inhibit NO synthesis by peritoneal macrophages stimulated in vitro with LPS. On the contrary, TETs were unable to decrease the ability of the macrophages to synthesize IL-1 alpha and TNF-alpha in vitro. These results indicate that TETs are not able to act directly on the synthesis of these cytokines, but they may modulate other pathways that could in turn be responsible for the inhibition of IL-1 alpha and TNF-alpha synthesis. Altogether, these results indicate that TETs are advantageous candidates for the prophylaxis and treatment of septic shock in mice, having both antimicrobial activity and the ability to inhibit endogenous TNF-alpha, IL-1 alpha, and iNOS, hence, exerting, potent anti-inflammatory effects.

Human herpesvirus type 8 DNA sequences in biological samples of HIV-positive and negative individuals in Sicily.

Abstract: Objective: To evaluate the circulation of a new human herpesvirus (HHV), HHV-8 or Kaposi's sarcoma (KS)-associated herpesvirus in a geographical area where a high incidence rate of classical KS was already present before the appearance of the AIDS epidemic. Design and methods: The study was carried out by analysing: (i) bioptic samples from classic, AIDS-associated KS, and controls; (ii) peripheral blood mononuclear cells (PBMC) from classic KS, HIV-positive subjects with and without KS and healthy HIV-negative individuals; (iii) semen samples from heterosexual HIV-positive and HIV-negative individuals affected or not by KS; and (iv) cervical swabs from HIV-negative healthy heterosexual females. All specimens were tested for the presence of HHV-8 DNA sequences by a two-step polymerase chain reaction. Results: Positive results were obtained in 90% of bioptic samples of classic KS and in 100% of AIDS-associated KS. Viral sequences were also present in 50% of PBMC of subjects with classic KS and AIDS-associated KS, in 10% of AIDS patients without the angiosarcoma, and in 11% of healthy HIV-negative individuals. Finally, HHV-8 DNA was detected in 13% of semen of HIV-negative heterosexual individuals and in 10% of AIDS patients without KS. Both PBMC and ejaculates from the same individual gave positive results. No HHV-8 sequences were found in cervical swabs. Conclusions: HHV-8 is widespread in the general population in Sicily since it was detected in PBMC and semen of heterosexual HIV-negative individuals and is not found only in high-risk groups. The viral load appears to be more elevated in a high-risk population and it may be ascribed to a viral reactivation. The higher incidence rates of KS in Sicily compared with northern Italy and other European countries might be related to the presence of HHV-8 in the general population.

CO2 output and δ13C(CO2) from Mount Etna as indicators of degassing of shallow asthenosphere

Abstract: An estimated average CO2 output from Etna's summit craters in the range of 13±3 Mt/a has recently been determined from the measured SO2 output and measured CO2/SO2 molar ratios. To this amount the CO2 output emitted diffusely from the soil (≈ 1 Mt/a) and the amount of CO2 dissolved in Etna's aquifers (≈ 0.25 Mt/a) must be added. Data on the solubility of CO2 in Etnean magmas at high temperature and pressure allow the volume of magma involved in the release of such an amount of this gas to be estimated. This volume of magma (≈ 0.7 km3/a) is approximately 20 times greater than the volume of magma erupted annually during the period 1971–1995. On the basis of C-isotopic data of CO2 collected in the Etna area and of new hypotheses on the source of Mediterranean magmas, significant contributions of CO2 from non-magmatic sources to the total output from Etna are unlikely. Such large outputs of CO2 and also of SO2 from Etna could be due to an anomalously shallow asthenosphere beneath the volcano that allows a continuous escape of gases toward the surface, even without migration of magma.

Stationary and non-stationary probability density function for non-linear oscillators

Abstract: A method for the evaluation of the stationary and non-stationary probability density function of non-linear oscillators subjected to random input is presented. The method requires the approximation of the probability density function of the response in terms of C-type Gram-Charlier series expansion. By applying the weighted residual method, the Fokker-Planck equation is reduced to a system of non-linear first order ordinary differential equations, where the unknowns are the coefficients of the series expansion. Furthermore, the relationships between the A-type and C-type Gram-Charlier series coefficient are derived.