706 research outputs found

    Realistic fluids as source for dynamically accreting black holes in a cosmological background

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    We show that a single imperfect fluid can be used as a source to obtain the generalized McVittie metric as an exact solution to Einstein's equations. The mass parameter in this metric varies with time thanks to a mechanism based on the presence of a temperature gradient. This fully dynamical solution is interpreted as an accreting black hole in an expanding universe if the metric asymptotes to Schwarzschild-de Sitter at temporal infinity. We present a simple but instructive example for the mass function and briefly discuss the structure of the apparent horizons and the past singularity.Comment: 5 pages, 2 figures. Updated references and minor changes to match the version accepted for publishing in PR

    Apoptosis and proliferation in thyroid carcinoma: correlation with bcl-2 and p53 protein expression.

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    The aim of this study was to determine the apoptotic cell death in 92 thyroid carcinomas of different histotypes (42 papillary, PTC; 12 poorly differentiated, PDC: 21 undifferentiated, UC; and 17 medullary, MC) by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end labelling (TUNEL). Apoptotic index (Al, evaluated as a percentage of TUNEL-positive cells of neoplastic cells) was calculated in each tumour. The AI was very low in all subtypes of thyroid carcinoma, ranging from a median value of 0.2 in PTC to 1.4 in UC. The proliferative activity was determined by immunohistochemistry using monoclonal antibody, MIB-1. The percentage of proliferating cells was significantly different among the histotypes, increasing with tumour aggressiveness (from the mean value of 3.1 for PTC to 5.6 for PDC and 51.8 for UC). In addition, the ratio between proliferative activity and apoptosis was significantly higher in UC than in the other histotypes. The expression of bcl-2 and p53 protein (important in the modulation of cell death) was correlated (bcl-2, inverse correlation, r2 = 0.1, P = 0.04; p53, direct correlation, r2 = 0.11, P = 0.02) with apoptotic index in PTC

    Self-consistency in Theories with a Minimal Length

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    The aim of this paper is to clarify the relation between three different approaches of theories with a minimal length scale: A modification of the Lorentz-group in the 'Deformed Special Relativity', theories with a 'Generalized Uncertainty Principle' and those with 'Modified Dispersion Relations'. It is shown that the first two are equivalent, how they can be translated into each other, and how the third can be obtained from them. An adequate theory with a minimal length scale requires all three features to be present.Comment: typos corrected, published with new title following referee's advic

    Response to erlotinib in a patient with lung adenocarcinoma harbouring the EML4-ALK translocation: A case report.

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    Lung cancer is the leading cause of cancer-associated mortality worldwide, and the mainstay of treatment remains to be personalised therapy. Tyrosine kinase inhibitors of the epidermal growth factor receptor (EGFR-TKIs) have been reported to exert a significant impact in the treatment of non-small cell lung cancer (NSCLC), particularly in patients harbouring mutations in the EGFR gene. The echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) gene translocation has been described in a subset of patients with NSCLC and possesses potent oncogenic activity. This translocation represents one of the most novel molecular targets in the treatment of NSCLC. Patients who harbour the EML4-ALK rearrangement possess lung tumours that lack EGFR or K-ras mutations. The present study reports the case of a patient possessing the EML4-ALK rearrangement that was initially treated with erlotinib and achieved a lasting clinical response. To the best of our knowledge, the current study is the first report of a clinical response to EGFR-TKI in a patient with lung adenocarcinoma harbouring the EML4-ALK fusion gene, but no EGFR mutations. However, as the disease progressed, the ALK gene status of the tumour was investigated, and based upon a positive result, the patient was treated with crizotinib and achieved a complete response. In conclusion, the present study suggests that the EML4-ALK rearrangement is not always associated with resistance to EGFR-TKIs. Further studies are required to clarify the biological features of these tumours and to investigate the mechanisms underlying the primary resistance to EGFR-TKIs when the EML4-ALK rearrangement is present

    Bcl-2 protein: a prognostic factor inversely correlated to p53 in non-small-cell lung cancer.

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    Non-small-cell lung cancer (NSCLC) prognosis is strictly related to well-established clinicopathological parameters which have unfortunately become insufficient in the prognostic evaluation of this type of cancer. As p53 and bcl-2 gene deregulations are frequently involved in several types of epithelial malignancies, we investigated the Bcl-2 and p53 protein expression in 91 and 101 cases of NSCLC respectively. The expression was then compared with established indicators of prognosis and biological behaviour of the tumours. No relationship was observed between Bcl-2 and either clinicopathological or biological parameters such as histology, grading, tumour status, nodal metastasis and proliferative activity evaluated by scoring proliferating cell nuclear antigen expression and Ki-67 immunoreactivity. However, the mean Bcl-2 expression was significantly lower in patients who developed metastasis during follow-up or died of metastatic disease (P = 0.006 and P = 0.01 respectively). Moreover, survival probability was higher in patients who expressed the Bcl-2 protein (P = 0.0002). In contrast with this, p53 protein accumulation was observed in tumours with metastatic nodal involvement (P = 0.02) or in patients who developed metastasis during follow-up (P = 0.01), although no correlation was found between p53 expression and overall survival. An inverse relationship was also found between Bcl-2 and the anti-oncogene protein product p53 (P = 0.01). Thus, a high proportion of NSCLCs express p53 and Bcl-2 proteins and their expression may have prognostic importance

    Tumour necrosis factor- α and transforming growth factor- β are significantly associated with better prognosis in non-small cell lung carcinoma: putative relation with BCL -2-mediated neovascularization

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    Recent in vivo and in vitro studies have demonstrated a wide spectrum of biologic activities of cytokines in the pathogenesis and progression of malignancy. Tumour necrosis factor alpha (TNF-α) and transforming growth factor beta (TGF-β) have emerged as two of the many host-derived mediators that seem to interfere with both antiproliferative and tumorigenic effects in malignant tumours including lung cancer. However, their association with tumour prognosis or prognostic factors has not yet been completely clarified. In this study, we assessed TNF-α and TGF-β mRNA expression by RT-PCR technique in 61 NSCLC samples, demonstrating the presence of TNF-α and TGF-β mRNA in 55.74% and 45.9% of cases, respectively. We also evaluated the expression of the two distinct transmembrane TNF receptors. TNFR-I and TNFR-II, with a PCR-positive signal in 70.49% and 65.57% of cases, respectively. In 49 of the 61 cases, we evaluated the prognostic impact of the two growth-inhibiting factors using the Kaplan–Meier analysis. In the univariate analysis patients without nodal metastatic involvement (P = 0.02), less advanced tumour stage (P = 0.02) or TNF-α and TGF-β positive cancers (P = 0.01 and P = 0.03) showed a favourable prognosis in terms of overall survival. Since our previous studies demonstrated a significant association between NSCLC behaviour, neoangiogenesis and bcl -2 expression, we investigated the putative relation between TNF-α and TGF-β on the one hand, and vascular count (as a measure of tumour angiogenesis) and bcl -2 protein expression, on the other hand. Our results showed a significant direct association between TNF-α and bcl -2 (P = 0.05) and an inverse association between TNF-α and microvessel count (P = 0.03). Moreover, as previously demonstrated, we observed a significant inverse correlation between bcl -2 protein expression and vascular count (P = 0.05), suggesting that the favourable effect of TNF-α on clinical outcome may be related to a bcl -2-mediated low neovascular development. © 2000 Cancer Research Campaig

    Primary tumor sidedness and benefit from FOLFOXIRI plus bevacizumab as initial therapy for metastatic colorectal cancer. Retrospective analysis of the TRIBE trial by GONO

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    Right-sided metastatic colorectal cancer (mCRC) patients have poor prognosis and achieve limited benefit from first-line doublets plus a targeted agent. In this unplanned analysis of the TRIBE study, we investigated the prognostic and predictive impact of primary tumor sidedness in mCRC patients and the differential impact of the intensification of the chemotherapy in subgroups defined according to both primary tumor sidedness and RAS and BRAF mutational status

    Spatio-temporal variability in Mediterranean rocky shore microphytobenthos

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    Knowledge of spatio-temporal variability of assemblages is the first step in identifying key factors affecting the abundance and distribution of organisms. Despite a long history of ecological studies on rocky intertidal habitats, there is still a lack of basic knowledge about the microphytobenthic components. We investigated the spatio-temporal variability of microphytobenthos in the northwest Mediterranean at multiple scales, including both seasonal and daily observations, as well as its composition. Spatial variability of microphytobenthic biomass varied significantly with season, with an increase in small-scale variance from cold to warm periods. Furthermore, during warmer months, small-scale variances (tens to hundreds of centimeters) were larger than large-scale components (tens to thousands of meters). These results suggest large spatiotemporal variation in the processes driving variation in microphytobenthic assemblages, including interactive effects among stressful abiotic conditions, substratum topography and grazing. In addition, observed variability on a daily scale suggested that microphytobenthos at the study site (dominated by cyanobacteria) might cope with stressful environmental conditions through both physiological and behavioral strategies at micro-spatial scales, including small movements within the substratum. Additional research on ecological and physiological aspects of rocky shore microphytobenthos is needed to better understand its role within interaction webs and primary productivity processes
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