1,721,300 research outputs found
Recent advances in the pathology of idiopathic thrombocytopenic purpura
No full textIdiopathic thrombocytopenic purpura (ITP) is an autoimmune disorder in which, for reasons that remain unclear, platelet surface proteins become antigenic and stimulate the immune system to produce autoantibodies and cytotoxic T lymphocytes. This results in immune-induced platelet destruction and suppression of platelet production.1-6 What causes the loss of tolerance to one’s own platelets remains unclear and is likely to be a result of a number of different co-operating factors including genetics (polymorphism in selected genes) and environment events (virusand bacteria-associated ITP).3 Both acute and chronic forms of disease can be distinguished. In children acute ITP is often associated with a viral or bacterial infection and generally resolves spontaneously within 6 weeks. Approximately 20% of children with acute ITP progress to the chronic form. In contrast ITP in adults is generally chronic and often requires treatment.
Human megakaryocyte biology and pathophysiology
No full textMegakaryocyte developmentin vitro requires the presence of at least two overlapping regulatory activities: a colony stimulating activity which promotes cellular proliferation and limited maturation and a second co-regulator
which directs maturational development. Since the responding meg cell populations represent a con-
tinuous spectrum of differentiating cell phenotypes, factor responsivenessclearly overlaps. These two rather
distinct processes as well as their complex regulation will be discussed in the first section of this review dealing
with the biology of megakaryocytopoiesis .
In the second part of this review we will consider a number of megakaryocytic disorders, comprising reactive and neoplastic diseases, which have been primarily characterized in the past by bone marrow histopathology
Traffic crash pattern modification as a result of a 30 km/h zone implementation. A case study in Turin (Italy)
Full text linkThe strategy of 30 km/h zones, referred to in the international context as "traffic calming" measures, serves to safeguard pedestrians, cyclists and motorcyclists, collectively referred to as “vulnerable road users” (VRU). Its main function is to compel drivers to observe a maximum speed limit of 30 km/h. However, urban infrastructure transformations modify traffic collision patterns and the involvement of road users, with a spatial temporal redistribution of events. This work seeks to study the effects on collision distribution resulting from the introduction of a 30 km/h zone to the Mirafiori Nord area in the city of Turin in late 2008. Collision frequencies, based on data provided by the Italian National Institute of Statistics (ISTAT), were evaluated over the period 2006-2016. Road traffic collisions involving both VRU and motorized users (“noVRU”) were taken into account. Decreases in collision frequency were found for noVRU related crashes, while the VRU crash rate remained essentially unchanged with only minor fluctuations consistent with the regression to the mean phenomenon. The countermeasures, which sought to protect VRU, were however very effective for noVRU. As the effects of each structural modification spill over into neighboring areas, the analysis of collision frequency was extended to a study area greater than the one in which the 30 km/h zone was realized. In fact, due to the migration of events, the reduction in the collision frequency in the speed restricted zone was accompanied by an increase in the
same frequency in the immediate surrounding area
The power of extracellular vesicles in myeloproliferative neoplasms: “Crafting” a microenvironment that matters
Full text linkMyeloproliferative Neoplasms (MPN) are acquired clonal disorders of the hematopoietic stem cells and include Essential Thrombocythemia, Polycythemia Vera and Myelofibrosis. MPN are characterized by mutations in three driver genes (JAK2, CALR and MPL) and by a state of chronic inflammation. Notably, MPN patients experience increased risk of thrombosis, disease progression, second neoplasia and evolution to acute leukemia. Extracellular vesicles (EVs) are a heterogeneous population of microparticles with a role in cell-cell communication. The EV-mediated cross-talk occurs via the trafficking of bioactive molecules such as nucleic acids, proteins, metabolites and lipids. Growing interest is focused on EVs and their potential impact on the regulation of blood cancers. Overall, EVs have been suggested to orchestrate the complex interplay between tumor cells and the microenvironment with a pivotal role in “education” and “crafting” of the microenvironment by regulating angiogenesis, coagulation, immune escape and drug resistance of tumors. This review is focused on the role of EVs in MPN. Specifically, we will provide an overview of recent findings on the involvement of EVs in MPN pathogenesis and discuss opportunities for their potential application as diagnostic and prognostic biomarkers
What's around the curve? A driving simulation experiment on compensatory strategies for safe driving along horizontal curves with sight limitations
Full text linkThis paper focuses on the behaviours adopted by road users when negotiating horizontal curves with sight limitations. Experiments at a driving simulator were conducted on two-lane highways in which drivers were confronted with a range of sight conditions generated by the manipulation of variables such as curve direction, radii and distance of lateral sight obstructions along horizontal curves. It was observed that most of the drivers adopted strategies which resulted in a stopping distance shorter than the available sight distance, thereby maintaining safe driving conditions. Some drivers reduced their speed, some increased the lateral distance from any sight obstructions along the roadside, some did both, while others did neither. A preliminary analysis indicated that the safety benefits resulting from a vehicle speed reduction strategy significantly outweigh those from a lateral shift in the lane. Further analyses on the 1246 cases investigated offered further support for this proposition, while revealing that a higher proportion of drivers opted for the first strategy for safety reasons. Moreover, visibility conditions (safe, partially safe, and unsafe) played a role in the choice of driving strategies. Results provide evidence that a significant group of drivers used the two strategies under severely restricted visibility conditions (i.e., along sharp radius curves); however, the strategies selected were independent of the driver speed profile (i.e., slower, average, or faster)
Spatial analysis of road crashes involving vulnerable road users in support of road safety management strategies
Full text linkOn urban road networks, approximately 2 out of 3 fatalities involve pedestrians, cyclists and motorcyclists, collectively referred to as “vulnerable road users” (VRU) due to their insufficient physical protection in the event of a collision. For a safer and more sustainable road transportation system, adequate protective countermeasures need to be introduced for this user category. However, related (and limited) resources restrict any safety improvements to certain high-risk sites with elevated rates of road traffic collisions. This study reports the results of a spatial distribution analysis of traffic collisions involving VRU in Turin over the period 2006-2016. The traffic road collisions database from the Italian National Institute of Statistics (ISTAT) was used for this purpose. Crash data were firstly geo-localized, and then analyzed using Geographic Information System technologies. A
cluster analysis and a Kernel Density estimation were used to build spatial patterns of crashes involving VRU. Hazardous sites were identified on a metropolitan scale. Incorrect estimates of the actual collision frequency, which are typical of studies conducted over short periods, were avoided by considering only those sites where collision rates remained significantly high throughout the entire observation period (eleven years). The results show that clusters occur at intersections, many of which are located along corridors affected by heavy traffic flows and wide cross-sections. A further analysis was conducted to explain the role played by the geometric configuration (layout) of most hazardous sections and intersections in the level and severity of injuries and fatalities
Is there a gender effect in polycythemia vera?
No full textIn recent times, there has been a growing interest in understanding the impact of gender on disease biology and clinical outcomes in Philadelphia-negative chronic myeloproliferative neoplasms. Among those, polycythemia vera (PV) is characterized by increased thrombotic risk, systemic symptoms, and overall reduced survival. Here, we aim to summarize data on whether and to what extent female sex can affect PV biology and outcome. To this end, we will discuss the latest acquisitions in terms of pathogenesis, diagnosis, epidemiology, clinical presentation and symptoms burden, thrombotic risk and related treatment strategies, and prognosis in female patients affected by PV
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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