548 research outputs found
Tra montagna e pianura. La saga dei Rossi da pastori a grandi industriali lanieri, in Lana, pecore, pastori. Tra il monte e il piano, a cura di G.F. Rodeghiero, Marostica, AttilioFraccaro Editore, 2019, pp. 66-70.
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Thrombopoietin receptor agonists in hereditary thrombocytopenias
No full textHereditary thrombocytopenias (HTPs) constitute a heterogeneous group of diseases characterized by a reduction in platelet count and a potential bleeding risk. As a result of advances in diagnostic methods, HTPs are increasingly being identified, and appear to be less rare than previously thought. Most HTPs do not have effective treatments, except for platelet transfusion when bleeding occurs and in preparation for procedures associated with a risk of bleeding. Preliminary clinical evidence suggests that thrombopoietin receptor agonists (TPO-RAs) with an established use in the treatment of certain acquired thrombocytopenias are well tolerated and provide clinical benefits in patients with some forms of HTP. These drugs may therefore be considered for the treatment of HTPs in clinical practice. However, caution and close monitoring are recommended, owing to the absence of long-term safety data and the potential risks posed by prolonged bone marrow stimulation in certain HTPs. In this review, we summarize the available clinical data on TPO-RAs in the treatment of HTPs, and discuss their use in patients with these disorders. We believe that TPO-RAs will play a major role in the treatment of HTPs, particularly myosin heavy chain 9-related disease, Wiskott-Aldrich syndrome, X-linked thrombocytopenia, and thrombocytopenia caused by THPO mutations
Greenhouse gas emissions from temperate European mountain forests
No full textForests are covering a substantial part of European mountains. The elongation
of the growing season due to climate change and warmer summers are
increasing the rate of soil respiration. However, the effect is at some sites partially
compensated by droughts. Temperate mountain forests ecosystems are mostly
releasing carbon dioxide whereas nitrogen oxides are of lesser importance. Societal
changes are also affecting the greenhouse gas emissions from forests. The structural
change in agriculture causes an increase of the forest area. The change in land use
from grassland to forest, leads to the formation of an organic litter layer on the soil
surface but to a reduction of the carbon input by decaying roots to the mineral layers.
Moreover, the effect of the increased carbon sequestration in the biomass of
more productive forests is partially offset by losses of carbon dioxide from the soil.
Climate change also calls for an adaptation of the strategy of forest management.
The economical feasibility of timber production in remote high-elevation forests
will not be signi!cantly increased. Nevertheless, even marginally productive mountain
forests need to be managed in order to ensure the provision of ecosystem services
such as protection against natural hazards. Mountain forests with a stable
stand structure can better cope with disturbances such as storms and biotic pressures,
thereby reducing the risk of carbon losses to the atmospher
Anisometria associata a prematurità: nostra esperienza su 350 casi in 6 anni di follow-up
No full textAssociation of factor V deficiency with factor V HR2
No full textBackground and Objectives. Factor V HR2 possesses decreased co-factor activity to activated protein C and an increased ratio of factor V1 to factor V2. Factor V HR2 is associated with a mild increase in the risk of venous thromboembolism although not all studies concur on this point. Design and Methods. Inconsistencies in results of the epidemiological studies may stem from a failure to identify other variables in factor V which might contribute to an increased risk of thrombosis in selected HR2 carriers. The aim of this study was to establish whether factor V deficiency increases the risk of venous thromboembolism when associated with HR2. Results. Four hundred and ninety-seven patients with venous thromboembolism and 498 controls were studied. HR2 was present in 12.5% of patients and 10.4% of controls. Factor V deficiency was associated with HR2 in 4.6% of patients and 1.0% of controls. The OR for venous thromboembolism in individual with HR2 alone was 1.2 (95% Cl 0.8-1.8), while it was 4.7 (95% Cl 1.8-12.5) for those with HR2 plus factor V deficiency. Interpretation and Conclusions. Patients with HR2 and factor V deficiency developed a thrombotic event earlier (median age 35 years) than patients with HR2 alone (median age 43 years, p = 0.018). Double heterozygosity for HR2 and a factor V defect, including factor V deficiency, increased the thrombotic risk afforded by HR2
Mutations in the thrombomodulin gene are rare in patients with severe thrombophilia
No full textBecause thrombomodulin plays a key role in the protein C pathway, we evaluated the contribution of thrombomodulin gene mutations to venous thrombosis. We examined 38 patients with recurrent, documented thrombotic events at a young age and a positive family history. Twelve individuals with low levels of soluble thrombomodulin in plasma were also studied. Finally, the allelic frequency of the Ala455Val polymorphism was estimated in 192 patients with at least one thrombotic event and in 369 age- and sex-matched asymptomatic controls. Two mutations were identified; G/A)201, in a severely thrombophilic patient and G/T 1456, in a patient with low soluble thrombomodulin levels. The first mutation has been reported by some, but not others, to be associated with moderately reduced levels of thrombomodulin. The second was identified previously in a patient with low soluble thrombomodulin, but expression studies failed to show functional changes in the mutant. Thrombomodulin gene mutations thus appear to be rare even in highly selected thrombophilic patients, and possibly functionally irrelevant. The allelic frequency of the Ala455Val polymorphism was identical in patients and controls. Considering the lack of a phenotype and the costly screening procedure, we recommend that thrombomodulin defects be sought only for research purposes
Bleeding tendency and efficacy of anti-haemorrhagic treatments in patients with type 1 von Willebrand disease and increased von Willebrand factor clearance
No full textAccelerated clearance of von Willebrand factor (VWF) has been recently identified as a major pathophysiologic mechanism inducing low VWF in some patients with von Willebrand disease (VWD). The frequency of bleeding and the best treatment of these patients have never been evaluated prospectively in large series of patients. It was the aim of the present study to prospectively evaluate clinical events of 60 heterozygous patients with VWD Vicenza (VWD-VI) carrying R1205H VWF mutation and 23 with C1130F mutation, both characterised by markedly increased VWF clearance. During 71 months of follow-up, 65% of patients with VWD-VI and 61% with C1130F required treatment. The rate of spontaneous bleeding requiring consultation/treatment was 7.5/100 patients-year in patients with C1130F mutation vs. 1.9/100 patients-year in those with R1205H (p=0.004). This difference persisted also by multivariate analysis adjusted for sex, age and blood group (hazard ratio [HR]=3.3 for C1130F, 95% con fidence interval [CI] 1.16-9.27) and females were at greater risk of bleeding (HR=3, 95%CI 1.01-9.93) because of menorrhagia. Only 3/15 (20 %) women in fertile age with VWD-VI compared to 8/9 (89 %) with C1130F mutation required consultation/treatment for menorrhagia (iron supplementation, combined oral contraceptives, tranexamic acid). Almost all dental extractions, minor surgeries and deliveries occurring during followup were successfully managed with desmopressin. Major surgery required factor VIII/VWF concentrates, but a few cases benefited from desmopressin. In conclusion, similar to patients with type 1 VWD, also in patients with increased VWF clearance desmopressin maintains a major therapeutic role
Optical design study, testing and qualification of a Schwarzschild-Couder telescope for CTA and an assessment on the Intensity Interferometry capabilities with CTA
No full textThere is a growing common effort in the very high energy community towards the development of new research infrastructures to answer the fundamental questions of modern high-energy astrophysics and astroparticle physics. The Cherenkov Telescope Array Observatory (CTAO) is an international project aiming to deploy two separate arrays to observe the whole VHE sky between E = 20 GeV up to E = 300 TeV in a long term plan of about 30 years of operations. CTA is designed to increase the sensitivity by a factor 10 at 1 TeV, to enlarge the detection area, the angular resolution and the field of view over the facilities operating today. The observatory will be characterized by high flexibility, enhanced monitoring and deep survey capabilities, short time scale and simultaneous observations in multiple fields.
This PhD thesis addresses the optical design study and testing of dual mirror Imaging Atmospheric Cherenkov Telescopes (IACTs) for the incoming CTAO.
All of the IACTs facilities currently operating rely on single mirror solutions, which are mostly parabolic or Davies-Cotton optical designs, however there is a novel interest in the development of dual mirror configurations following the Schwarzschild-Couder optical design. This peculiar design, based on two highly aspherical mirrors promises wide-field, aplanatic telescopes characterized by small f-numbers and more compact structures. Dual mirror solutions allow use smaller camera pixels (3-6 mm) based on Silicon Photo Multiplier technology in substitution of the larger Photo Multiplier Tubes (1 inch) currently in use. The increased complexity in terms of optics manufacturing, replication and alignment is motivated from the attractive new capabilities of such configuration. In this context the Italian National Institute for Astrophysics (INAF) supported by the Italian Ministry of Education, University and Research (MIUR), is developing a small sized telescope prototype for CTA, named ASTRI, which is based upon the Schwarzschild-Couder optical design.
The present work deals with the challenging realization of this optical configuration that has never been applied to IACTs. After two introductory chapters on the gamma-ray astronomy and the ASTRI optical design and its main subsystems (chapters 1 and 2), the performances of this system are compared with those of the other common wide-field telescopes in use for Cherenkov observations and for other applications in astrophysics (chapter 3). This comparative study is based on a commercial ray tracing software into which the optical designs of the envisaged telescopes are reproduced.
Subsequently in chapter 4, an extended study of the ASTRI capabilities in relation to the performance and environmental requirements issued by CTA is presented in a detailed analysis of compliance supported by ray tracing simulations, finite element analysis and tolerance studies.
In chapter 5 the work on the qualification tests of the secondary mirror gives an insight into the complexity of the Schwarzschild-Couder optics. The realization of this optical element is challenging in relation to currently available technologies, in particular concerning the cost requirements imposed by the CTA project. These constraints and the large sagitta of the mirror (190 mm) requires the use of the hot slumping technique in substitution of the cold slumping and diamond milling approaches usually used in the manufacturing of mirrors for Cherenkov applications. The results of a careful and extended test campaign on a mirror prototype have indicated that this manufacturing technique can provide a reliable engineering process of production for such large, highly aspherical optics. With a perspective on the science with future large telescopes as those provided by CTA, an assessment study upon the potentialities of the Intensity Interferometry (II) technique is carried out in chapter 6. In particular, a new kind of observation based on II is explored; the method aims to estimate the direct distance of the celestial objects. The order of magnitudes of the problem parameters space and the sensitivity that CTA and other future large observatories should achieve is estimated by means of numerical simulations. A short-term concept of experiment to assess the reliability of this new method is also discussed in relation to a pilot measurement that could be pursued with the state of the art technology
Phenotypic homozygous activated protein C resistance associated with compound heterozygosity for Arg506Gln (factor V Leiden) and His1299 Arg substitutions in factor V
No full textTwo patients from two unrelated families with a history of thrombosis showed severe plasma activated protein C (APC) resistance. However, genotypic analysis demonstrated that the patients were heterozygous for factor V (FV) Leiden mutation. Coagulation studies revealed that FV clotting activity and antigen were similarly reduced at about 50% of normal in the patients. One brother of propositus A also showed the same abnormalities. Genetic analysis showed that, in addition to FV Leiden mutation in exon 10 of the FV gene (G1691A), these patients had a transition in exon 13 of the FV gene (A4070G; R2 allele) predicting His1299Arg substitution in the mature FV. Study by RT-PCR of platelet FV mRNA indicated that the mRNA produced by the FV gene, marked by the R2 allele, was reduced in amount in both pseudohomozygous patients of family A. The R2 allele has previously been demonstrated to be significantly associated with plasma FV deficiency in the Italian population. The presence of FV deficiency did not protect the propositi from thrombosis. These data confirm that genotypic analysis is mandatory in patients with phenotypic severe APC resistance before these patients are definitely classified as homozygotes for FV Leiden and that further genotypic analysis is advisable
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