178,941 research outputs found
Pathogenesis of histiocytoses
No full textLangerhans cell histiocytosis (LCH) is a disease of unknown etiology showing clonal proliferation of Langerhans-like cells or their precursors [1, 16]. Pathologic LCH cells appear to be in an immature state of activation and/or differentiation [1]. They accumulate in peripheral tissue and express inflammatory cytokines resulting in their own recruitment and retention [21]. Moreover, activated CD40 ligand expressing T helper cells are found to be the predominant source of cytokines and growth factors in LCH lesions [3]. The “cytokine storm” seems to be further enhanced by the interaction of CD40 expressing LCH cells and CD40 ligand expressing T-cells [3]. High levels of granulocyte-macrophage colony-stimulating factor, tumor-necrosis factor alpha, interleukin-3, and other cytokines are potential chemoattractants for recruiting eosinophils, neutrophils, marcrophages, and CD34+ Langerhans cell precursors into the LCH lesion [3, 7]. These cytokines are known to contribute directly to the development of fibrosis, necrosis, and osteolysis [11]. They are also supposed to play a role in the presence of several other myeloid cell types; the multinucleated giant cell (MGC), amongst others, was found in LCH lesions [8]. MGCs are believed to play a major role in tissue destruction, as they are express osteoclast markers [8]. Remarkably, though various inflammatory cytokines are present in LCH lesions, LCH cells remain immature and do not maturate [3]. Lesional microenvironment seems to play a role in the maintenance of the phenotype of LCH cells [3]
Epidemiology of histocytoses
No full textLangerhans cell histiocytisis (LCH) is the most common of the histiocytic disorders [39]. It represents a spectrum of several clinical entities chracterized by a disorder of antigenpresenting dendritic cells of the immune system. Its epidemiology is poorly understood and based mainly on a few international and regional studies of defined populations [34]. The overall incidence rate varies from 2.6 to 8.9 children per million per year [1, 19, 34, 36]. Children of any age can be affected, however the peak age of presentation, in children, is between the ages of one and three [34]. LCH is also diagnosed in adults [37] but only a few reports are available describing LCH patients with onset during adulthood [3]. Some studies reveal a greater prevalence of LCH among male children [19]. On the other hand, in adults, a preponderance of females is documented with onset as late as the ninth decade of life [26]. Dissemitaned LCH is described to present most frequently in the first year of life [19]. Congenital self-healing LCH is an uncommon form of LCH, which is usually present at birth or in the neonatal period [23]
Dermoscopy
No full textBecause melanoma in advanced stages is still incurable, early detection is indispensable to reduce mortality. With the introduction of dermoscopy into the clinical practice, the diagnostic accuracy of pigmented skin lesions can be improved. Dermoscopy is a noninvasive diagnostic technique for the in vivo observation in dermatology. This technique enables the clinician to visualize pigmented structures of the epidermis, dermo–epidermal junction, and papillary dermis, which are not visible to the naked eye. The structures observed by dermoscopy correlate with histopathological findings. Dermoscopy opens a new dimension in the clinical morphology of pigmented skin lesions but diagnostic accuracy depends significantly on the experience of the examiner
Cutaneous lymphoma
No full textCutaneous lymphomas, like other lymphomas, are systemic diseases by definition. Therefore, surgery has limited indications. However, primary cutaneous B-cell lymphomas (CBCL), such as follicle center lymphomas and large cell primary cutaneous CD30+ T-cell lymphomas, may present as a single nodule in the skin. In these cases, because investigation on tumor material is necessary, an excision biopsy might be a good alternative to an incisional biopsy. In the case of surgical treatment of a nodule in primary cutaneous lymphomas, a safety margin of at least 1 cm should be applied, although there are no supporting clinical trails
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Proteomic scan for tyrosinase peptide antigenic pattern in vitiligo and melanoma: role of sequence similarity and HLA-DR1 affinity
No full textImmune responses contribute to the pathogenesis of vitiligo and target melanoma sometimes associated with vitiligo-like depigmentation in some melanoma patients. We analyzed the sera from patients with vitiligo and cutaneous melanoma for reactivity toward tyrosinase peptide sequences 1) endowed with low level of similarity to human proteome, and 2) potentially able to bind HLA-DR1 Ags. We report that the tyrosinase autoantigen was immunorecegnized with the same molecular pattern by sera from vitiligo and melanoma patients. Five autoantigen peptides composed the immunodominant anti-tyrosinase response: aa95-104FMG FNCGNCK; aa175-182 LFVWMHYY; aa 176-190FVWMHYYVSMDALLG; aa222-236IQKLTGDENFTIPYW, and aa233-247 IPYWDWRDAEKCDIC. All of the five antigenic peptides were characterized by being (or containing) a sequence with low similarity level to the self proteome. Sera from healthy subjects were responsive to aa 95-104FMGFNCGNCK, aa222-236IQKLT GDENFTIPYW, and aa 233-247 IPYWDWRDAEKCDIC, but did not react with the aa 175-182LFVWMHYY and aa176-190FVW MHYYVSMDALLG peptide sequences containing the copper-binding His180 and the pculocutaneous albinism I-A variant position F176. Our results indicate a clear-cut link between peptide imnninogenkiiy and low similarity level of the corresponding amino acid sequence, and are an example of a comparative analysis that might allow to comprehensively distinguish the epitopic peptide sequences within a disease from those associated to natural autoantibodies. In particular, these data, for the first time, delineate the linear B epitope pattern on tyrosinase autoantigen and provide definitive evidence of humoral immune responses against tyrosinase. Copyright © 2005 by The American Association of Immunologists, Inc
Proteomic scan for tyrosinase peptide antigenic pattern in vitiligo and melanoma: role of sequence similarity and HLA-DR1 affinity
No full text"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going 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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