An epidemiological and biomolecular survey of cystic echinococcosis in cattle in Sardinia.
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Age Distribution↗
Biomedical subjects
A Scala
Publications and source records attributed to A Scala.
Serum antibodies to Dicrocoelium dendriticum in sheep from Sardinia (Italy).
An indirect enzyme-linked immunosorbent assay (ELISA) with Dicrocoelium dendriticum excretory/secretory antigens was used to evaluate the presence of serum antibodies against the trematode in 738 sheep randomly chosen in Sardinia (Italy). Coprological sedimentation was used to discover egg-output. Seropositivity was detected in 86.2% tested sheep, whereas faecal prevalence was 6.7%; all that were faecal-positive also were ELISA-positive.
Animals↗
Helminths found in hedgehogs (Erinaceus europaeus) in three areas of Italy.
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Animals↗
Impact of known and unknown diabetes on in-hospital mortality from ischemic stroke.
BACKGROUND AND AIMS: The effect of known diabetes on in-hospital mortality from ischemic stroke is still debated whereas the role of unknown diabetes is virtually unexplored. This study evaluates the impact of known and unknown diabetes on in-hospital mortality from ischemic stroke. METHODS AND RESULTS: We have retrospectively evaluated the records of 286 consecutive cases of ischemic stroke hospitalized from January 1998 to December 2000 at the Department of Internal Medicine of the General Hospital located in the western area of Naples. Fasting plasma glucose level < 7 mmol/L identified non diabetic subjects. Known diabetes mellitus was diagnosed by history of diabetes and/or hypoglycemic therapy, unknown diabetes was defined as a random plasma glucose level > or = 11 mmol/L and/or in-hospital fasting glucose > or = 7 mmol/L on two or more occasions. Severity of stroke was defined using the Canadian Neurological Score (CNS). According to these criteria, 144 subjects were non diabetics, 99 had known diabetes and 43 had unknown diabetes. Subjects with known diabetes showed a higher prevalence of female sex, hypertension and increased triglyceride levels as compared with non diabetic subjects (p < 0.01). Subjects with unknown diabetes were older (p < 0.01) and showed a more severe CNS (3.4 +/- 2.7) than non diabetic and diabetic subjects (5.8 +/- 2.6 and 5.8 +/- 2.6, respectively; p < 0.01). In-hospital mortality was significantly higher in the unknown diabetic group (44%) as compared with known diabetic (15%) and non diabetic groups (12%) (p < 0.001). This finding was independent of neurological deficit, age, atrial fibrillation and history of previous stroke. CONCLUSIONS: Our study shows that unknown diabetes, more than known diabetes, is a strong risk factor for in-hospital mortality in subjects with acute ischemic stroke.
Age Factors↗
Update on burning mouth syndrome: overview and patient management.
Burning Mouth Syndrome (BMS) is a chronic pain syndrome that mainly affects middle-aged/old women with hormonal changes or psychological disorders. This condition is probably of multifactorial origin, often idiopathic, and its etiopathogenesis remains largely enigmatic. The present paper discusses several aspects of BMS, updates current knowledge, and provides guidelines for patient management. There is no consensus on the diagnosis and classification of BMS. The etiopathogenesis seems to be complex and in a large number of patients probably involves interactions among local, systemic, and/or psychogenic factors. In the remaining cases, new interesting associations have recently emerged between BMS and either peripheral nerve damage or dopaminergic system disorders, emphasizing the neuropathic background in BMS. Based on these recent data, we have introduced the concepts of "primary" (idiopathic) and "secondary" (resulting from identified precipitating factors) BMS, since this allows for a more systematic approach to patient management. The latter starts with a differential diagnosis based on the exclusion of both other orofacial chronic pain conditions and painful oral diseases exhibiting muco-sal lesions. However, the occurrence of overlapping/overwhelming oral mucosal pathologies, such as infections, may cause difficulties in the diagnosis ("complicated BMS"). BMS treatment is still unsatisfactory, and there is no definitive cure. As a result, a multidisciplinary approach is required to bring the condition under better control. Importantly, BMS patients should be offered regular follow-up during the symptomatic periods and psychological support for alleviating the psychogenic component of the pain. More research is necessary to confirm the association between BMS and systemic disorders, as well as to investigate possible pathogenic mechanisms involving potential nerve damage. If this goal is to be achieved, a uniform definition of BMS and strict criteria for its classification are mandatory.
Age Factors↗
Water and its energy landscape.
We present an overview of the recent studies on the properties of the potential energy surface for a simple model of water. We emphasize the relations between PES properties and dynamics in supercooled states for the model and discuss possible future application of the PES studies.
Journal Article↗
Chronobiology of Oestrus ovis (Diptera: Oestridae) in Sardinia, Italy: guidelines to chemoprophylaxis.
Oestrus ovis (Linné 1761) larvae are obligatory parasites of the nasal and sinus cavities of sheep and goats. Infestation is prevalent in hot and dry regions, such as Mediterranean countries. The current work was developed to establish the chronobiology of O. ovis in Sardinia, to determine the most suitable time for chemoprophylaxis. A survey was carried out during 1998, and sheep heads were collected monthly from local flocks. A total of 443 heads was examined, and the prevalence of oestrosis was 73.8%. We collected 2,691 larvae (mean = 6.07 +/- 9.52), and the intensity was greatest in November. The humoral immune response against the nasal bot fly was analyzed by means of an indirect-ELISA using second-instar O. ovis excretory and secretory antigens. A seasonal variation in the antibody levels was observed, increasing from April and peaked in June and in September. A significant correlation was observed between first instar intensity and the mean relative humidity (r2 = 0.120; P < 0.05), and between second-instar intensity and the mean temperature (r2 = 0.241; P < 0.05). Three periods in the chronobiology of O. ovis were defined: diapause (October-February), the active phase ofthe endogenous cycle (March-September) and the exit phase (May-September). Our results showed that treatment in October-November was suitable, because first instars were in diapause, preventing the development of first into second instars, and second into third instars.
Animals↗
Sheep oestrosis (Oestrus ovis Linné 1761, Diptera: Oestridae) in Sardinia, Italy.
Oestrosis, the nasal myiasis of sheep and goats, is caused by the larvae of Oestrus ovis L. 1758 (Diptera, Oestridae) that develop from the first to the third stage larva in the nasal cavities and frontal sinuses of affected animals. The authors report the results of an epidemiological study of oestrosis of sheep in Sardinia, Italy. Heads of 6-month to 10-year-old Sardinian sheep (n=566) from 124 free-ranging flocks were examined for the presence and location O. ovis larvae from December 1996 to November 1997. Larvae were collected, counted, and larval stages were identified. O. ovis larvae were found in 100% of examined flocks and in 91% (514/566) of examined sheep. The monthly prevalence ranged from 69% in May to 100% in July. First stage larvae were found in 82% (463) of all heads examined, second stage larvae in 65% (367) and third stage larvae in 10% (56). The majority of sheep harboured first stage larvae, with prevalences of over 80% throughout most of the study period. The prevalence of O. ovis found in this study of Sardinian sheep is the highest reported in the Mediterranean area. The high percentage of first stage larvae found throughout the entire study period may be due to a brief period of decreased rate of larval maturation, in particular in December 1996 (96%) and January-October 1997 (94%). Third stage larvae were consistently present, often however, with extremely low prevalences compared to total larval burden.
Animals↗
Dynamics of supercooled water in configuration space.
We study the potential energy surface (PES) sampled by a liquid modeled via the widely studied extended simple point charge (SPC/E) model for water. We characterize the curvature of the PES by calculating the instantaneous normal mode (INM) spectrum for a wide range of densities and temperatures. We discuss the information contained in the INM density of states, which requires additional processing to be unambiguously associated with the long-time dynamics. For the SPC/E model, we find that the slowing down of the dynamics in the supercooled region-where the ideal mode coupling theory has been used to describe the dynamics-is controlled by the reduction in the number of directions in configuration space that allow a structural change. We find that the fraction f(dw) of the double-well directions in configuration space determines the value of the diffusion constant D, thereby relating a property of the PES to a macroscopic dynamic quantity; specifically, it appears that square root D is approximately linear in f(dw). Our findings are consistent with the hypothesis that, at the mode coupling crossover temperature, dynamical processes based on the free exploration of configuration space vanish, and processes requiring activation dominate. Hence, the reduction of the number of directions allowing free exploration of configuration space is the mechanism of diffusion implicitly implemented in the ideal mode coupling theory. Additionally, we find a direct relationship between the number of basins sampled by the system and the number of free directions. In this picture, diffusion appears to be related to geometrical properties of the PES, and to be entropic in origin.
Journal Article↗
Waterlike anomalies for core-softened models of fluids: two-dimensional systems.
We use molecular-dynamics simulations in two dimensions to investigate the possibility that a core-softened potential can reproduce static and dynamic anomalies found experimentally in liquid water: (i) the increase in specific volume upon cooling, (ii) the increase in isothermal compressibility upon cooling, and (iii) the increase in the diffusion coefficient with pressure. We relate these anomalies to the shape of the potential. We obtain the phase diagram of the system and identify two solid phases: a square crystal (high-density phase) and a triangular crystal (low-density phase). We also discuss the relation between the anomalies observed and the polymorphism of the solid. Finally, we compare the phase diagram of our model system with experimental data, noting especially the line of temperatures of maximum density, the line of pressures of maximum diffusion constant, and the line of temperatures of minimum isothermal compressibility.
Journal Article↗
Thermodynamic and structural aspects of the potential energy surface of simulated water.
Relations between the thermodynamics and dynamics of supercooled liquids approaching a glass transition is a topic of considerable interest. The potential energy surface of model liquids has been increasingly studied, since it provides a connection between the configurational component of the partition function on the one hand, and the system dynamics on the other. This connection is most obvious at low temperatures, where the motion of the system can be partitioned into vibrations within a basin of attraction and infrequent interbasin transitions. In this work, we present a description of the potential energy surface properties of supercooled liquid water. The dynamics of this model have been studied in great detail in recent years. We locate the minima sampled by the liquid by "quenches" from equilibrium configurations generated via molecular dynamics simulations, and then calculate the temperature and density dependence of the basin energy, degeneracy, and shape. The temperature dependence of the energy of the minima is qualitatively similar to simple liquids, but has anomalous density dependence. The unusual density dependence is also reflected in the configurational entropy, the thermodynamic measure of degeneracy. Finally, we study the structure of simulated water at the minima, which provides insight on the progressive tetrahedral ordering of the liquid on cooling.
Journal Article↗
Thermodynamically important contacts in folding of model proteins.
We introduce a quantity, the entropic susceptibility, that measures the thermodynamic importance-for the folding transition-of the contacts between amino acids in model proteins. Using this quantity, we find that only one equilibrium run of a computer simulation of a model protein is sufficient to select a subset of contacts that give rise to the peak in the specific heat observed at the folding transition. To illustrate the method, we identify thermodynamically important contacts in a model 46-mer. We show that only about 50% of all contacts present in the protein native state are responsible for the sharp peak in the specific heat at the folding transition temperature, while the remaining 50% of contacts do not affect the specific heat.
Amino Acids↗
"Tube-guided" implant of bioprosthetic shunt for hemodialysis.
Implant of a bovine-derived vascular bioprosthesis as arterio-venous shunt for hemodialysis may raise some problems regarding tunnel fashioning. Therefore, we have proposed a simple "tube-guided" technique to make implant safer and to avoid complications.
Animals↗
Anti-tumor-promoting effects of glycoglycerolipid analogues on two-stage mouse skin carcinogenesis.
Four glycoglycerolipid analogues, 1-O-hexanoyl-2-O-beta-D-glucopyranosyl-sn-glycerol (1), 1-O-hexanoyl-2-O-beta-D-galactopyranosyl-sn-glycerol (2), 2-O-(6-O-hexanoyl-beta-D-galactopyranosyl)-sn-glycerol (3) and 2-O-(6-O-hexanoyl-alpha-D-galactopyranosyl)-sn-glycerol (4), potent in vitro inhibitors of 12-O-tetradecanoylphorbol-13-acetate (TPA) induced Epstein-Barr virus early antigen (EBV-EA) activation, were submitted to an in vivo two-stage mouse skin carcinogenesis test, using dimethylbenz[a]anthracene (DMBA) and TPA. The study was extended to two deacylated galactosylglycerol structures, 1-O-beta-D-galactopyranosyl-sn-glycerol (5) and 3-O-beta-D-galactopyranosyl-sn-glycerol (6). All the tested compounds exhibited remarkable anti-tumor-promoting effects on mouse skin tumor promotion, the 1-hexanoate 2 being the most active among the glycoglycerolipids until now studied.
9,10-Dimethyl-1,2-benzanthracene↗
Saddles in the energy landscape probed by supercooled liquids.
We numerically investigate the supercooled dynamics of two simple model liquids exploiting the partition of the multidimensional configuration space in basins of attraction of the stationary points (inherent saddles) of the potential energy surface. We find that the inherent saddle order and potential energy are well-defined functions of the temperature T. Moreover, by decreasing T, the saddle order vanishes at the same temperature (T(MCT)) where the inverse diffusivity appears to diverge as a power law. This allows a topological interpretation of T(MCT): it marks the transition from a dynamics between basins of saddles (T > T(MCT)) to a dynamics between basins of minima (T < T(MCT)).
Journal Article↗
Classes of small-world networks.
We study the statistical properties of a variety of diverse real-world networks. We present evidence of the occurrence of three classes of small-world networks: (a) scale-free networks, characterized by a vertex connectivity distribution that decays as a power law; (b) broad-scale networks, characterized by a connectivity distribution that has a power law regime followed by a sharp cutoff; and (c) single-scale networks, characterized by a connectivity distribution with a fast decaying tail. Moreover, we note for the classes of broad-scale and single-scale networks that there are constraints limiting the addition of new links. Our results suggest that the nature of such constraints may be the controlling factor for the emergence of different classes of networks.
Interpersonal Relations↗
Configurational entropy and diffusivity of supercooled water
As a liquid approaches the glass transition, its properties are dominated by local potential minima in its energy landscape. The liquid experiences localized vibrations in the basins of attraction surrounding the minima, and rearranges via relatively infrequent inter-basin jumps. As a result, the liquid dynamics at low temperature are related to the system's exploration of its own configuration space. The 'thermodynamic approach' to the glass transition considers the reduction in configuration space explored as the system cools, and predicts that the configurational entropy (a measure of the number of local potential energy minima sampled by the liquid) is related to the diffusion constant. Here we report a stringent test of the thermodynamic approach for liquid water (a convenient system to study because of an anomalous pressure dependence in the diffusion constant). We calculate the configurational entropy at points spanning a large region of the temperature-density plane, using a model that reproduces the dynamical anomalies of liquid water. We find that the thermodynamic approach can be used to understand the characteristic dynamic anomalies, and that the diffusive dynamics are governed by the configurational entropy. Our results indicate that the thermodynamic approach might be extended to predict the dynamical behaviour of supercooled liquids in general.
Journal Article↗
Instantaneous normal mode analysis of supercooled water
We use the instantaneous normal mode approach to provide a description of the local curvature of the potential energy surface of a model for water. We focus on the region of the phase diagram in which the dynamics may be described by mode-coupling theory. We find that the diffusion constant depends on the fraction of directions in configuration space connecting different local minima, supporting the hypothesis that the dynamics are controlled by the geometric properties of configuration space. Furthermore, we find a relation between the number of basins accessed in equilibrium and the connectivity between them.
Journal Article↗