1,721,169 research outputs found
STUDIO PROSPETTICO DI CONFRONTO TRA LA RISONANZA MAGNETICA DIFFUSION-WEIGHTED E LE TECNICHE STANDARD DI VALUTAZIONE DELLA MALATTIA OSSEA NEL MIELOMA MULTIPLO: VALORE PROGNOSTICO DELLA NUOVA METODICA, CORRELAZIONE CON LA RISPOSTA ALLA TERAPIA E CON LE CARATTERISTICHE BIOLOGICHE DI MALATTIA
Full text linkBone disease in multiple myeloma (MM) patients is usually assessed by skeletal X-ray (XR) and magnetic resonance imaging (MRI) of the spine (MRIS). Diffusion-weighted MRI (DW-MRI) is an innovative whole-body MRI that detects malignant lesions studying water diffusion in tissues. This prospective study compared DW-MRI with XR and MRIS for the assessment of lytic bone lesions in MM patients. Patients had symptomatic MM at diagnosis (stage I-III Durie and Salmon [D&S]) requiring the first treatment, or MM at relapse before the start of the salvage treatment. An exploratory substudy enrolled asymptomatic patients with D&S stage I MM. The primary objective of the study was to assess whether DW-MRI could detect a higher number of lytic bone lesions than XR and MRIS. The secondary objectives were: to assess whether there was a correlation between the number of lesions and response to therapy; to assess whether the number of lesions could be correlated with progression; and, to assess whether the DW-MRI could detect more lesions than standard whole-body MRI (WB-MRI). The explorative objective of the substudy was to evaluate whether DW-MRI could detect more lytic bone lesions than standard imaging in asymptomatic MM patients. Along with clinical objectives, the study was aimed at correlating the data coming from the experimental imaging technique with the biologic characteristics of disease. Patients performed XR, MRIS, WB-MRI, and DW-MRI at diagnosis or at relapse, after the treatment and 6 months thereafter (symptomatic MM) or every 6 months for 1 year (asymptomatic MM). MRIS and DW-MRI were done in a single 45-minutes session by a standard 1.5 Tesla MRI scanner. DW-MRI consisted of multiple stacked axial EPI sequences at 4 b-values, evaluated by PET-like MIP and MPR reconstructions at the highest b-value (1000). Along with the radiology exams, patients performed at the same timepoints serological and histological evaluations of disease, including cytogenetics with FISH before starting treatment. The study enrolled 50 patients between 2008 and 2010, 36 of them in the main study, 14 in the substudy. Patients in the main study evaluable for the results were 35. Their median age was 65 years (range, 33-81), D&S stage was I for 48.6% of them, II for 5.7%, and III for 45.7%; ISS staging was I for 71.4% of patients. The 57.4% of patients had IgG, 25.7% had IgA MM, 8.6% had non-secerning and micromolecolar MM. 42.9% of patients were at diagnosis, 57.1% at relapse. Median bone marrow infiltration was 30%. FISH on selected CD138+ plasma cells was normal in 28.6% of patients; 42.9% of them had a del(13), 22.9% of them had t(11;14); 8.6% had t(4;14) and 5.7% del(17). Between the 1st and the 2nd exam, patients received a treatment including lenalidomide (35.3%), thalidomide (23.5%), or bortezomib (47.0%). 97% of patients received steroids (dexametasone or metilprednisone). 26.5% of patients received an autologous transplant, and 5.9% an allogeneic transplant. Response was as following: sCR 10.3%, VGPR 24.1%, PR 37.9%, SD 10.3%, PD 17.2%. At the 3rd radiology exam, the response status was: 8% sCR, 36% VGPR, 28% PR, 20% SD and 8% PD. At the first radiology exam, XR showed a median of 1 bones with focal lesions (range, 0-10). MRIS showed a median of 0 lesions (range, 0.0-4.0). The association of XR and MRIS (XR+MRIS) showed a median of 2 lesions (range, 0-10), WB-MRI a median of 2 lesions (range, 0-18, p=0.03), and DW-MRI a median of 5.8 lesions (range, 0-18, p=5 lesions/patient detected by DW-MRI. OS was similar in these 2 groups (p=0.48), whereas patients with >=5 lesions had a worse PFS (p=0.018) and RFS (p=0.009), and a higher RI (p=0.002). After the treatment, patients is CR had a median of 0 lesions, those in VGPR 2 lesions, those in PR 3 lesions, and those in SD in PD 2 and 3 lesions, respectively. The average of lesions progressively rose from 0.7 (patients in CR) to 4.8 lesions (patients in PD). Standard methods showed a median of 0-2 lesions less than DW-MRI consistently with response. This association between response and DW-MRI was observed also in patients at the 3rd exam (0 lesions for patients in CR, 5 in patients in PD), with an increasing difference in detecting lesions according to disease status compared to the standard methods. The DW-MRI showed less lesions in the 2nd timepoint compared to the 1st timepoint (p=0.04), consistently with the fact that most patients responded to therapy, and remained stable between the 2nd and 3rd exam (p=0.21). The XR and XR+MRI remained the same during all the longitudinal 3 evaluations (p=1.0, p=0.12, and p=0.27, p=0.10, respectively). There was a trend for patients with IgA MM to have more lesions in DW-MRI (87.5% vs 50% of IgG MM, p=0.15). Patients with positive Bence-Jones had more lesions than those with negative BJ (60% vs 21.4%, p=0.06), and similarly those with positive urinary immunofixation (63.3% vs 30%, p=0.15). Freelite ratio was weakly correlated with the bone with lesions in DW-MRI (p=0.11, corr=0.29), but correlation increased considering the microscopic lesions detected by DW-MRI (corr=0.33, p=0.06). Patients at diagnosis had a 45.4% of lesions >=5 compared to 75.0% of those relapsed (p=0.21), and patients with D&S stage III had frequently >=5 lesions compared to lower stages (52.6% vs 37.5%). Patients with FISH at higher cytogetic risk (Mayo stratification) had more lesions compared to those at standard risk (73.6 vs 45.4%, p=0.24). There was a high correlation between the number of lesions showed by DW-MRI and LDH value before treatment (corr=0.44, p=0.008). Patients with high level of ICTP (>4.5) had >=5 lesions in DW-MRI. The substudy including asymptomatic patients showed a median of 0 lesions (range, 0-2) at XR, 0 at MRIS (range, 0-3), 1 lesion at XR+MRIS (range, 0-3), 0.5 lesions at WB-MRI (range, 0-6, p=0.81) and 2.5 lesions at DW-MRI (range, 0-8, p=0.04). After 6 and 12 months of follow-up the lesions were in median 0 for XR, MRIS and XR+MRIS, 0 for WB-MRI (p=0.67 and p=0.62), and 1.0 for DW-MRI at both timepoints (p=0.17 and p=0.22).
In conclusion, DW-MRI was superior than standard radiological methods in detecting lytic bone lesions for symptomatic MM patients at diagnosis requiring treatment or at relapse. The number of lesions were correlated with PFS, RFS and RI. The lesions detected by the new technique correlated with response as categorized by IMWG criteria. The number of lesions were also correlated with LDH, and less strongly with Freelite ratio, Bence-Jones proteinuria or urinary immunofixation, high risk FISH, IgA isotype, relapsed disease. DW-MRI showed to be superior also in detecting lytic bone lesions in asymptomatic patients. The exams were feasible and well tolerated. DW-MRI is a new radiological method that is very promising in an highly specialized setting for the evaluation of bone lesions in MM
Ecological and morphological correlates of residual fat reserves in passerine migrants at their spring arrival in southern Europe
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Correlates of timing of spring migration in birds: a comparative study of trans-Saharan migrants
No full textThe evolution of migratory strategies in birds is likely to have been influenced by ecological as well as socio-sexual factors in both wintering and breeding areas. In this comparative study, we analysed timing of spring passage of 38 long-distance migratory bird species that winter south of the Sahara desert and breed in Europe, in relation to wintering and breeding latitudes, moult strategy, nesting site (open vs. cavity), and sexual dimorphism in size and coloration, which may reflect intensity of sexual selection. We employed a large data set consisting of more than 190 000 individuals ringed during spring migration in the Mediterranean Sea. We found that the species that migrated earlier were those wintering farther north, nesting in cavities and showing the largest degree of sexual size dimorphism (SSD). However, sexual dichromatism was not related to migration date. Among passerine species, moulting wing-feathers in Africa delayed migration. We found no support for the energetic constraint hypothesis, which proposes that early arrival selects for large male size, since early arriving species were not larger than late arriving ones. Thus, the observed associations suggest that variation in migration schedules at the interspecific level may have evolved in relation to ecological factors and SSD, possibly reflecting the intensity of mating competition. (c) 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 199-210
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
Replacement of body feathers is associated with low pre-migratory energy stores in a long-distance migratory bird, the barn swallow (Hirundo rustica)
No full textMoult and pre-migratory fuelling are energy-demanding processes in birds, usually showing a limited degree of temporal overlap. The barn swallow Hirundo rustica, a strictly aerial insectivorous, long-distance passerine migrant (15-20 g), accumulates conspicuous energy stores (up to 30-40% of lean body mass) before embarking on the autumn migratory flight between western European breeding areas and African sub-Saharan winter quarters. During the pre-migratory fattening period (September October), both adult and juvenile birds replace body (contour) feathers. The seasonal overlap between moult and energy storing was studied in barn swallows in Italy. Data from 23 000 birds, measured during eight study seasons, were analysed to investigate whether the simultaneous replacement of body feathers and fuelling was associated with reduced energy stores. Among all age and sex-classes, non-moulting individuals showed a relatively greater level of energy stores compared to moulting birds. This was particularly evident during the last phase of the pre-migratory fuelling period, when birds were building up energy stores at maximum rate. The proportion of moulting birds was greater among adults as compared to juveniles, and adult males moulted faster/earlier than females. The frequency of individuals with growing feathers among the innermost primary feathers was greater among birds replacing body feathers. The presence of moulting wing feathers in adult birds only marginally affected energy stores, as compared to the replacement of body feathers. Hence, our data show a negative association between replacement of contour feathers and energy stores in a long-distance migratory bird, suggesting that a physiological trade-off between these two energy-demanding processes may occur, and that a late moult may ultimately have a negative effect on the successful termination of the migratory journey
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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