Showing papers by "University of Palermo published in 1992"

Hepatitis C virus infection as a risk factor for hepatocellular carcinoma in patients with cirrhosis. A case-control study.

Abstract: Objective To determine whether chronic hepatitis C virus (HCV) infection is an independent risk factor for hepatocellular carcinoma and whether it increases the cirrhosis-related risk for hepatocellular carcinoma. Design Two pair-matched case-control studies. Setting A referral-based hospital. Patients In study I, 212 patients with hepatocellular carcinoma (197 of whom had known underlying cirrhosis) were compared with controls who had chronic nonhepatic diseases. In study II, the 197 patients with hepatocellular carcinoma and cirrhosis were compared with 197 pair-matched controls who had cirrhosis but not hepatocellular carcinoma. Measurements Levels of antibody to HCV (anti-HCV), hepatitis B surface antigen (HBsAg), and antibody to hepatitis B core antigen (anti-HBc) were assayed, and alcohol abuse was assessed by history. Main results In study I, 151 patients (71%) with hepatocellular carcinoma were anti-HCV positive compared with 11 controls (5%) with chronic nonhepatic diseases (odds ratio, 42; 95% CI, 22 to 95). Multivariate analysis showed that anti-HCV was an independent risk factor for hepatocellular carcinoma (odds ratio, 69; CI, 15 to 308). The analysis also showed that HBsAg (odds ratio, 8.7; CI, 1.5 to 50) and anti-HBc (odds ratio, 4.2 (CI, 1.7 to 11) were risk factors for hepatocellular carcinoma. No statistically significant interaction was found between anti-HCV and the markers of HBV infection. In study II, 146 patients (74%) with hepatocellular carcinoma and cirrhosis were anti-HCV positive compared with 122 patients (62%) with cirrhosis alone (odds ratio, 1.8; CI, 1.1 to 2.8). Multivariate analysis confirmed that anti-HCV (odds ratio, 2.0; CI, 1.3 to 32) and HBsAg (odds ratio, 2.0; CI, 1.0 to 4.2) were independent risk factors for hepatocellular carcinoma. Conclusions Hepatitis C virus infection is a risk factor for hepatocellular carcinoma, apparently by inducing cirrhosis and, to a lesser extent, by enhancing the risk in patients with cirrhosis. Hepatitis C virus infection acts independently of HBV infection (another risk factor) and of alcohol abuse, age, or gender.

A high-frequency survey of the southern Galactic plane for pulsars

Abstract: Results of an HF survey designed to detect young, distant, and short-period pulsars are presented. The survey detected a total of 100 pulsars, 46 of which were previously unknown. The periods of the newly discovered pulsars range between 47 ms and 2.5 ms. One of the new discoveries, PSR 1259-63, is a member of a long-period binary system. At least three of the pulsars have ages less than 30,000 yr, bringing the total number of such pulsars to 12. The majority of the new discoveries are distant objects with high dispersion measures, which are difficult to detect at low frequencies. This demonstrates that the survey has reduced the severe selection effects of pulse scattering, high Galactic background temperature, and dispersion broadening, which hamper the detection of such pulsars at low radio frequencies. The pulsar distribution in the southern Galaxy is found to extend much further from the Galactic center than that in the north, probably due to two prominent spiral arms in the southern Galaxy.

Prevalence of Parkinson's disease and other types of parkinsonism A door‐to‐door survey in three Sicilian municipalities

Abstract: We investigated the prevalence of Parkinson's disease and other types of parkinsonism in a Sicilian population using a door-to-door two-phase approach. This design called for the administration of a brief screening instrument to all subjects who, on November 1, 1987, were residents of Terrasini (Palermo Province), Santa Teresa di Riva (Messina Province), and Riposto (Catania Province), Sicily (N = 24,496). Study neurologists using specified diagnostic criteria extensively investigated those subjects who screened positive. We found 63 subjects affected by Parkinson's disease, 21 with secondary parkinsonism, and seven with unspecified parkinsonism. The crude prevalence per 100,000 population was 371.5 for all types of parkinsonism and 257.2 for Parkinson's disease; for both entities, prevalence increased steeply with age and showed an inconsistent sex pattern. Our prevalence figures for Parkinson's disease are higher than those previously reported in Italy or elsewhere, which may be due, in part, to more complete case-ascertainment.

Recognizable picture languages

Abstract: The purpose of this paper is to propose a new notion of recognizability for picture (two-dimensional) languages extending the characterization of one-dimensional recognizable languages in terms of local languages and alphabetic mappings. We first introduce the family of local picture languages (denoted by LOC) and, in particular, prove the undecidability of the emptiness problem. Then we define the new family of recognizable picture languages (denoted by REC). We study some combinatorial and language theoretic properties of REC such as ambiguity, closure properties or undecidability results. Finally we compare the family REC with the classical families of languages recognized by four-way automata.

Increased thromboxane biosynthesis in type IIa hypercholesterolemia.

Abstract: BACKGROUND Increased platelet thromboxane (TX)A2 production has been described in type IIa hypercholesterolemia. To verify the relevance of these capacity-related measurements to the actual rate of TXA2 biosynthesis in vivo, we studied the urinary excretion of its major enzymatic metabolites in 46 patients with type IIa hypercholesterolemia and 20 age-matched controls. METHODS AND RESULTS Urinary 11-dehydro-TXB2 and 2,3-dinor-TXB2 were measured by previously validated radioimmunoassays. The excretion rate of 11-dehydro-TXB2 was significantly (p less than 0.001) higher in patients (68.7 +/- 35.1 ng/hr, mean +/- SD) than in controls (22.4 +/- 9.4 ng/hr), with metabolite excretion greater than 2 SD of the normal mean in 74% of the patients. Urinary 11-dehydro-TXB2 was significantly (p less than 0.01) correlated with the threshold aggregating concentration of collagen (r = -0.641) and arachidonate (r = -0.734) and with agonist-induced platelet TXB2 production in vitro (r = 0.647 and 0.748, respectively). Moreover, a statistically significant correlation (r = 0.673, p less than 0.001, n = 66) was found between 11-dehydro-TXB2 excretion and total plasma cholesterol. The enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor simvastatin (20 mg/day for 6 months) significantly reduced cholesterol levels by 22-28% and urinary 11-dehydro-TXB2 excretion by 32-42% in 10 patients. However, the reduction in the latter did not correlate with the reduction in the former and may have resulted from a nonspecific effect of simvastatin. Moreover, selective inhibition of platelet cyclooxygenase activity by low-dose aspirin (50 mg/day for 7 days) was associated with cumulative inhibition of 11-dehydro-TXB2 excretion by approximately 70% in six patients. CONCLUSIONS TXA2 biosynthesis is enhanced in the majority of patients with type IIa hypercholesterolemia; this is, at least in part, a consequence of abnormal cholesterol levels, as suggested by the correlation between the two. Low-dose aspirin can largely suppress increased metabolite excretion, thus suggesting that it reflects TXA2-dependent platelet activation in vivo.

Crystallization of Polymer Melts Under Fast Cooling. II. High-Purity iPP

Abstract: SYNOPSIS Samples of a high-purity isotactic polypropylene (iPP) were quenched from the melt so as to monitor cooling history. A continuous variation of morphology and crystal structure was obtained with cooling rate. This is discussed in relation to sample thermal history evidencing that cooling history relevant to quenched samples is in the neighborhood of 90°C. In particular the samples are essentially mesomorphic when at this temperature cooling rates larger than 80°C/s were adopted, while below a few tens of °C/s only a­ monocline form is obtained. Densities of quenched samples were compared with predictions of an isokinetic extrapolation of Avrami model of polymer crystallization kinetics.

Cathepsin D in the malignant progression of neoplastic diseases (review).

Abstract: Recent studies suggest that aspartic proteinase Cathepsin D may be implicated in the process of tumor invasion and metastasis. In fact several in vitro observations showed that this proteinase may facilitate the spread of neoplastic cells through different mechanisms related to its proteolytic activity, by acting at different levels of the metastatic cascade. Cathepsin D may promote tumor cell proliferation by acting as an autocrine mitogen through the activation of latent forms of growth factors or by interacting with growth factor receptors. The enzyme was also shown to be able to degrade in vitro extracellular matrix and to activate latent precursors forms of other proteinases involved in the invasive steps of the metastatic process. Although unequivocal proof of its active role in promoting these processes also in vivo has not been obtained so far, recent clinical observations which showed a positive correlation between levels of expression of Cathepsin D activity and malignant progression of some human neoplasms further support this hypothesis. These findings warrant extensive experimental and clinical studies to better assess the pathophysiological role of this acid proteinase in the spread of neoplastic diseases and suggest new and more selective therapeutic approaches to the treatment of human neoplasms.

Structure and crystallization kinetics of poly(L-lactic acid)

Abstract: A structural investigation is described of poly(L-lactic acid) by best fitting of powder X-ray diffraction patterns. The examined sample shows the already known pseudo-orthorhombic α-form, and it was possible to determine the location of the two 103 polymeric helices in the unit cell and the size distribution of the crystallites. Furthermore, a study is reported of the crystallization kinetics of the above cited polymer by light depolarization measurements in an optical microscope. The crystallization kinetic constants in bulk were evaluated in a temperature range (70–165°C) wider than that previously resulting from measurements of radial growth of spherulites.

Histone deacetylase inhibitors: Apoptotic effects and clinical implications (Review)

Abstract: It has been shown that epigenetic modifications play an important role in tumorigenesis. Thus, affecting epigenetic tumorigenic alterations can represent a promising strategy for anticancer targeted therapy. Among the key chromatin modifying enzymes which influence gene expression, histone acetyltransferases (HATs) and histone deacetylases (HDACs) have recently attracted interest because of their impact on tumor development and progression. Increased expression of HDACs and disrupted activities of HATs have been found in several tumor types, with a consequent hypoacetylated state of chromatin that can be strictly correlated with low expression of either tumor suppressor or pro-apoptotic genes. Histone deacetylase inhibitors (HDACIs) represent a new and promising class of antitumor drugs that influence gene expression by enhancing acetylation of histones in specific chromatin domains. HDACIs have been shown to exert potent anticancer activities inducing cell cycle arrest and apoptosis. Notably, a high efficacy of these drugs has been selectively revealed in malignant cells rather than in normal cells. Moreover, the therapeutic potential of these agents is also supported by the evidence that HDACIs downregulate genes involved in tumor progression, invasion and angiogenesis. Several HDACIs are currently under clinical investigation, including vorinostat (SAHA), romidepsin (depsipeptide, FK-228), LAQ824/LBH589 and belinostat (PXD101), compounds that have shown therapeutic potential in many types of malignancies including solid tumors. Based on the ability of HDACIs to regulate many signaling pathways, co-treatment of these compounds with molecular targeted drugs is a promising strategy against many types of tumors.

Left ventricular diastolic and systolic function in normotensive obese subjects: influence of degree and duration of obesity

Abstract: The present study was carried out to evaluate systolic and diastolic parameters in overweight and moderately obese, but otherwise healthy subjects, and in a lean control group, to determine whether degree and duration of obesity can influence left ventricular function. A total of 27 subjects, 17 overweight or with moderate obesity and 10 lean, healthy subjects were included. Patients were divided into three groups according to their body mass index (BMI) and to Garrow's criteria as follows: lean control group (BMI less than 25 kg.m-2); overweight subjects (BMI from 25 to 30 kg.m-2); moderately obese subjects (BMI greater than 30 less than 40 kg.m-2). Systolic and diastolic parameters were measured using blood pool gated radionuclide angiography. Left ventricular (LV) ejection fraction (EF), peak ejection rate (PER), time to PER (tPER), peak filling rate (PFR) and time to PFR (tPFR) were evaluated. PER and PFR values were normalized for end-diastolic volume (EDV). EF and PFR were significantly lower (P less than 0.05) both in moderately obese and in overweight subjects and tPFR was significantly (P less than 0.05) prolonged in both groups in comparison to lean controls. Only in moderately obese subjects was PER significantly (P less than 0.05) decreased and tPER significantly (P less than 0.05) prolonged in comparison to lean controls. As compared to overweight individuals, moderately obese subjects were characterized by a significant decrease (P less than 0.05) in LVEF and PER and by a significant increase (P less than 0.05) in tPER, without relevant change in PFR and in tPFR.(ABSTRACT TRUNCATED AT 250 WORDS)

Past and present role of the Indian-fig prickly-pear (Opuntia ficus-indica (L.) Miller, Cactaceae) in the agriculture of sicily

Abstract: Of prickly-pear cacti occurring in Sicily, the most widespread and economically important isOpuntia ficus-indica (L.) Miller. In Sicily it has, since its introduction, played an important role in the exploitation of marginal areas. The Sicilian experience is described with reference to the historical outlines and the present intensive production of late fruit. Information on historical and actual uses of the plant and its products (flowers, cladodes, fruits) is given.

Basalt magmatism along the passive continental margin of SE Brazil (Campos basin)

Abstract: The SE-Brazil passive continental margin is characterized by tholeiitic magmatism that is particularly widespread in the marginal Campos basin, facing the inland flood basalts of the adjacent Parana basin. Campos magmatism is represented by Early Cretaceous (EC; 134–122 Ma) flood basalts and minor Upper Cretaceous-Early Tertiary basalt flows and intrusives, which were emplaced in a basin with attenuated crustal thickness (20 km). Petrography, mineral chemistry, wholerock geochemistry and Sr−Nd isotope composition emphasize that the EC-Campos basalts have suffered extensive seawater interaction which caused enrichment in MgO, FeO total, K2O, Rb and Ba, and depletion in SiO2 and CaO, while Zr, Nb, Y and REE remained virtually constant in samples with loss-on-ignition values less than 4 wt%. In general, Campos basalts have bulkrock chemistry similar to those of the inland Parana tholeiites (140–130 Ma) with relatively low concentrations of incompatible elements and TiO2 ( 16) MORB (mid-ocean-ridge basalt) mantle in simple binary mixing models. On the whole, the Early Cretaceous Campos basalts appear as an easterly, younger extension of the northern Parana volcanism and probably erupted during early stages of the major riftingprocesses which caused continental thinning. It is notable that in the Campos marginal basin both the basalt magmatism contemporaneous with the continental break-up, as well as that which occurred after the S. America-Africa separation, appears substantially related to subcontinental lithosphere and a Dupal-like OIB (ocean-island basalt) (e.g. Tristan da Cunha) source components.

Pulsed high-energy gamma-rays from the radio pulsar PSR1706-44

Abstract: Gamma radiation above 100 MeV in energy has been detected from the radio pulsar PSR1706-44. The gamma emission forms a single broad peak within the pulsar period of 102 ms, in contrast to the two narrow peaks seen in the other three known high-energy gamma-ray pulsars. The emission mechanism in all cases is probably the same, the differences arising from the geometry of the magnetic and rotation axes and the line of sight. Gamma-ray emission accounts for as much as 1 percent of the total neutron star spindown energy in these pulsars, much more than emerges at optical or radio frequencies. Thus, study of this emission is important in understanding pulsar emission and evolution.

Therapeutic synergism between hyaluronic acid and dexamethasone in the intra-articular treatment of osteoarthritis of the knee: a preliminary open study.

Abstract: In vitro studies on the effects of dexamethasone on human synovial cells have shown that with high concentrations of the steroid in the culture medium cellular activity was completely blocked whereas with low concentrations (10(-6)M), cellular density decreased but there was an increase in the synthesis of RNA, DNA, protein and hyaluronic acid. These data, coupled with clinical experience of using intra-articular hyaluronic acid to treat patients with osteoarthritis of the knee, prompted the investigators to carry out an open, randomized study of the use of very small doses of dexamethasone in association with hyaluronic acid in 40 osteoarthritic patients. Twenty patients received a weekly intra-articular injection of 20 mg sodium hyaluronate in 2 ml phosphate buffer for 5 weeks; the other 20 patients followed a similar treatment regimen, the only difference being the addition of 0.4 mg dexamethasone phosphate to the first injection. Clinical examination of the knee was made before each injection, 7 days after the fifth injection and 60 days after the start of the trial. Rating scale assessments were made at each visit of spontaneous pain, pain during the day, at night, weight bearing and whilst walking. The results showed that whilst a progressive decrease in all pain parameters was evident and persisted after the end of treatment in both patient groups, pain intensity decreased more rapidly and to lower levels in all but weight-bearing pain, as did improvement in joint mobility, in the combined treatment group. Local tolerance was good with both treatment regimens, with no untoward signs or symptoms at any time.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of famotidine in severe exocrine pancreatic insufficiency with persistent maldigestion on enzymatic replacement therapy. A long-term study in cystic fibrosis.

Abstract: In patients with pancreatic exocrine insufficiency, the use of pancreatic enzyme does not abolish steatorrhea in some cases. We carried out a long-term prospective study in an attempt to clarify the effectiveness of the associated use of famotidine to enzymatic supplementation on fat absorption and nutritional parameters of patients with pancreatic insufficiency due to cystic fibrosis. We studied 10 patients, mean age 12.5 years, with persistent steatorrhea on enzymatic supplementation. A double-blind crossover design was used and famotidine (1 mg/kg/day) or placebo was given as adjuvant to enzymatic preparations for either of two six-month periods. A statistically significative reduction in fecal wet weight (P less than 0.0001), an improvement in the coefficient of fat absorption (P less than 0.01) and in the steatocrit values (P less than 0.028) were found on famotidine. Moreover, the weight and the height increases were greater after famotidine than after placebo period (respectively, P less than 0.012 and P less than 0.01); also the serum calcium and triglycerides levels were higher after the period on famotidine (respectively, P less than 0.0025 and P less than 0.025). No adverse effects of famotidine were noted. These data suggest that famotidine is a useful adjuvant to pancreatic enzyme therapy in patients with severe pancreatic insufficiency and persistent maldigestion on large doses of pancreatic supplements; in fact, famotidine improves not only fat absorption but the nutritional status of the patients.

Gastric emptying in infants with gastroesophageal reflux. Ultrasound evaluation before and after cisapride administration.

Abstract: The present study aimed to evaluate gastric emptying in children with gastroesophageal reflux (GER) by means of real-time ultrasonography, on the basis of measurements of the cross-sectional area of the gastric antrum. Twelve children with GER were studied (seven males, five females; age range, 3-13 months) and compared with 12 normal control children (six males, six females; age range, 3-13 months). The diagnosis of GER was confirmed by 24-h esophageal pH-monitoring. The GER patients had a significantly greater antral area than the controls at 90, 105, and 120 min after eating a standard meal (cow's milk formula, 300 ml/m2 body surface area); in addition, final gastric emptying time was significantly greater in the patients than in the controls (145 +/- 36.9 versus 78.7 +/- 19.3 min; p less than 0.0025). After 8 weeks of treatment with cisapride (0.3 ml/kg, three times a day) 24-h esophageal pH-monitoring and ultrasonography studies were repeated in the patients. The total percentage reflux time was significantly lower (p less than 0.038), and ultrasonography showed a decreased antral area at all the various study times, with no significant difference between patients and controls; final gastric emptying time was also significantly lower than before treatment (p less than 0.009). Furthermore, in the GER patients there was a significant correlation between gastric emptying time and the sum of the various reflux times recorded in the 2 h after all meals over the 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Large-eddy simulation of turbulent flow and heat transfer in plane and rib-roughened channels

Abstract: Large-eddy simulation results are presented and discussed for turbulent flow and heat transfer in a plane channel with and without transverse square ribs on one of the walls. They were obtained with the finite-difference code Harwell-FLOW3D, Release 2, by using the PISOC pressure-velocity coupling algorithm, central differencing in space, and Crank-Nicolson time stepping. A simple Smagorinsky model, with van Driest damping near the walls, was implemented to model subgrid scale effects. Periodic boundary conditions were imposed in the streamwise and spanwise directions. The Reynolds number based on hydraulic diameter (twice the channel height) ranged from 10 000 to 40 000. Results are compared with experimental data, k-ϵ predictions, and previous large-eddy simulations.