170,074 research outputs found
Infectious agents in mucosa-associated lymphoid tissue-type lymphomas: Pathogenic role and therapeutic perspectives
No full textMucosa-associated lymphoid tissue (MALT) lymphoma probably constitutes the best in vivo model showing how complex interplay between B lymphocytes and the surrounding microenvironment may lead to a neoplastic disorder. After the seminal discovery of the pathogenic association between Helicobacter pylori and gastric MALT lymphomas, evidence suggests the possible involvement of other infectious agents in the development of MALT lymphomas arising at different body sites. Although several other bacteria (Borrelia burgdorferi, Campylobacter jejuni, and Chlamydia psittaci) and viruses (Hepatitis C virus) seem to play a role in lymphomas presenting at different locations, a possible common pathogenic mechanism is emerging. Several lines of evidence suggest that different infectious agents might provide a chronic antigenic stimulation that elicits host immune responses able to promote clonal B-cell expansion. This model is also substantiated by the increasing number of patients with MALT lymphomas who exhibit objective clinical responses after antimicrobial therapy. A multidisciplinary approach is critical to better understand the complex etiopathogenesis of MALT lymphomas with the final goal to dissect the clinicopathologic heterogeneity of these disorders and design more tailored preventive and therapeutic approaches
The Use of Ceria in FCC, Dehydrogenation and Other Catalytic Applications Ed., Catalytic Science Series - vol. 2, pp. 483-500, 2002. -Imperial College Press
No full textInfectious etiopathogenesis of extranodal lymphomas
No full textSeveral infectious agents are established causes of non-Hodgkin’s lymphoma in humans. They include human immunodeficiency virus (HIV), Epstein-Barr virus (EBV), human herpes virus 8 (HHV-8), hepatitis C virus (HCV), and Helicobacter pylori. In addition, a causal role is suspected for hepatitis B virus (HBV), Borrelia burgdorferi, Campylobacter jejuni, and various Chlamydia species. For some of these agents, notably HIV, HHV-8, H. pylori, Chlamydia, and B. burgdorferi, the association seems specific to one or a few types of extra - nodal lymphomas, while EBV is associated with a variety of nodal and extranodal lymphomas. In the case of HCV, the risk of both nodal and extranodal lymphomas seems increased among chronically infected individuals. No data are available on HBV and risk of extranodal lymphoma. In the following sections, the epidemiological and pathogenetic evidence linking infectious agents to extra - nodal lymphoma is reviewed. Infectious agents may contribute to lymphomagenesis by two main pathogenetic mechanisms. First, a direct role is played mainly by viruses such as EBV and HHV-8, which infect target cells and express a variety of viral products that promote cell growth and survival. Additional environmental and genetic factors contribute to the malignant phenotype. The virus genome is usually present in all tumor cells. Secondly, infectious agents, mainly bacteria, may indirectly contribute to lymphomagenesis by providing a chronic antigenic stimulus that would drive the development of extranodal lymphomas along a continuum pathway, starting from the development of acquired mucosaassociated lymphoid tissue (MALT), through low-grade lymphoma, and ultimately leading to high-grade tumors. Proliferation of B cells may be dependent on the contact with infiltrating antigen-specific CD4+ helper T cells. Antigens derived from the infectious agent may be cross-reactive with self-antigens, which, in turn, may further sustain B cell growth. This model indicates that infectious agents could trigger autoimmune reactivity and emphasizes the likely relevant role of autoimmune mechanisms in the pathogenesis of some extranodal lymphomas (Figure 4.1). © 2008 by Taylor & Francis Group, LLC
Towards a High Level Linter for Data Science
No full textDue to its interdisciplinary nature, the development of data science code is subject to a wide range of potential mistakes that can easily compromise the final results. Several tools have been proposed that can help the data scientist in identifying the most common, low level programming issues. We discuss the steps needed to implement a tool that is rather meant to focus on higher level errors that are specific of the data science pipeline. To this end, we propose a static analysis assigning ad hoc abstract datatypes to the program variables, which are then checked for consistency when calling functions defined in data science libraries. By adopting a descriptive (rather than prescriptive) abstract type system, we obtain a linter tool reporting data science related code smells. While being still work in progress, the current prototype is able to identify and report the code smells contained in several examples of questionable data science code
A comprehensive approach to modelling confined explosion phenomena within atex 1999/92/CE directive
No full textPreliminary bench and pilot plant experiences for on board wastewater treatment by ozone
No full textActivation of infiltrating cytotoxic T lymphocytes and lymphoma cell apoptotic rates in gastric MALT lymphomas - Differences between high-grade and low-grade cases
No full textIn this study, we have characterized infiltrating T lymphocytes from 13 low-grade and 17 high-grade primary gastric MALT lymphomas by immunohistochemistry, with particular regard to the presence, activation, and topographic distribution of cytotoxic effecters. Although the prevalence of CD4+ and CD8+ cells was similar in low- and high-grade lymphomas, higher numbers of TIA-1+ cytotoxic effecters were found in this latter group of cases (11.6 versus 7.8%; P = 0.004), Activation of CD8+ cytotoxic T lymphocytes (CTLs) was significantly more pronounced in high than in low-grade lymphomas, as shown by immunostaining for perforin (8.7 versus 4.0%; P = 0.001) and granzyme-B (GrB) (8.7% versus 3.0%; P < 0.0001), Of note, CD20/GrB double labeling showed that high-grade lymphomas carried a markedly higher content (about ninefold) of activated CTLs relative to the number of CD20+ lymphoma B cells (0.081 +/- 0.076 versus 0.009 +/- 0.011; P < 0.0001). Moreover, high-grade lymphomas showed significantly increased apoptotic rates compared to low grade cases (5.3 and 1.1% of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells, respectively; P < 0.0001). In the whole series, the percentage of GrB+ cells and the GrB+/CD20+ ratio showed a strong Linear correlation with the number of TUNEL-labeled cells. These findings, together with the frequent colocalization of CTLs and TUNEL+ neoplastic cells, suggested that apoptotic death of lymphoma cells may be due at least in part to the killing by cytotoxic effecters. Our results are consistent with the occurrence of host antitumor cell-mediated immune responses in gastric MALT lymphomas, Moreover, the finding of stronger cytotoxic responses in high than in low-grade cases is of potential usefulness in the design of more effective therapeutic strategies for the management of these disorders.In this study, we have characterized infiltrating T lymphocytes from 13 low-grade and 17 high-grade primary gastric MALT lymphomas by immunohistochemistry, with particular regard to the presence, activation, and topographic distribution of cytotoxic effectors. Although the prevalence of CD4+ and CD8+ cells was similar in low- and high-grade lymphomas, higher numbers of TIA-1+ cytotoxic effectors were found in this latter group of cases (11.6 versus 7.8%; P = 0.004). Activation of CD8+ cytotoxic T lymphocytes (CTLs) was significantly more pronounced in high- than in low- grade lymphomas, as shown by immunostaining for perforin (8.7 versus 4.0%; P = 0.001) and granzyme-B (GrB) (8.7% versus 3.0%; P < 0.0001). Of note, CD20/GrB double labeling showed that high-grade lymphomas carried a markedly higher content (about ninefold) of activated CTLs relative to the number of CD20+ lymphoma B cells (0.081 ± 0.076 versus 0.009 ± 0.011; P < 0.0001). Moreover, high-grade lymphomas showed significant..
CARBON-DIOXIDE HYDROGENATION ON RHODIUM SUPPORTED ON TRANSITION-METAL OXIDES - EFFECT OF REDUCTION TEMPERATURE ON PRODUCT DISTRIBUTION
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
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