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Now showing items 1 - 10 of 10

  • The Hybrid Method Applied to the Plate-Finned Tube Evaporator Geometry

    Starace, G.   Fiorentino, M.   Meleleo, B.   Risolo, C.  

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  • A Hybrid Method for the Cross Flow Compact Heat Exchangers Design

    Starace, G.   Fiorentino, M.   Longo, M.P.   Carluccio, E.  

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  • DNA content distribution of in vivo and in vitro lines of Lewis lung carcinoma

    Starace, G.   Badaracco, G.   Greco, C.   Sacchi, A.   Zupi, G.  

    The kinetic features of Lewis lung carcinoma (3LL), and of two in vitro and two in vivo derivative lines were studied by flow cytometry. The in vitro lines C108 and BC215 show the same tetraploid DNA content, and a very similar cell cycle structure, characterized by a prevalent S fraction. Also, the in vivo lines, the original 3LL and M1087, show a tetraploid DNA content, while the BM21548 is characterized by a hyperdiploid DNA mode and a broader distribution of DNA values. No difference in the modal DNA value is found between each primary tumor and the corresponding lung metastases for all the in vivo lines. An increase in the G1 component corresponding to a decrease in the S fraction is observed during the tumor growth. These kinetic features were related to some malignant properties of 3LL lines, such as growth pattern and metastatic potential. A direct correlation is not always possible to establish. [The relevance of these findings to assaying tumor chemotherapy efficacy is discussed.].
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  • Interferons antagonize gamma-ray-induced depression of natural immunity

    Fuggetta, M. P.   Tricarico, M.   Starace, G.   Pepponi, R.   Bonmassar, E.  

    Purpose: The aim of this study was to determine the inhibitory effects of in vitro radiation on the number and function of natural killer (NK) cells and to investigate the capability of interferons (IFNs) to restore the activity of NK, depressed by gamma-rays. Methods and Materials: Mononuclear cells (MNC) were obtained from intact or in vitro irradiated (20 Gy) Peripheral blood collected from healthy donors. Alternatively, MNC were irradiated (20 Gy) after separation from intact whole blood. The in vitro treatment of MNC with IFNs (alpha, beta, or gamma, 200 UI/ml) was performed at different times after or before radiation. The NK activity (4 h-51Cr release test), the percentage of CD16+/CD56+ cells and apoptosis (cytometric analysis), and binding (microscopic observation) were evaluated on Days 0, 1, 2, and 5 from gamma-ray exposure and IFNs treatment. Results: The in vitro treatment of irradiated MNC with betaIFN after radiation completely reverses the inhibitory effects of gamma-rays on human NK activity. betaIFN do not reduce the apoptosis induction by radiation and don't modify the number of CD16- or CD56-positive cells. The binding between irradiated effectors and tumor cells (K562) appears partially increased in betaIFN-treated MNC. Conclusions: The results of the present investigation suggest a possible role of betaIFN in reversing the detrimental effect of radiation on human natural immunity and provide a rational basis for in vivo use of betaIFN in cancer radiotherapy.
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  • A stochastic model for cell debris in flow cytometry

    Bruni, C.   Ferrante, L.   Koch, G.   Scoglio, C.   Starace, G.  

    An important problem in analyzing flow cytometry DNA measurements, especially for tumor samples, is the presence of background noise, mainly resulting from cellular debris. Several models have been proposed for subtracting this contribution from DNA content histograms. In the present paper we propose a model for background debris distribution based on a specific mechanism for the DNA fragmentation process of the cell nucleus. In particular, we suggest that the fragmentation is more likely to occur in the sites which are closer to the end points of the DNA chain. This accounts for the observed higher frequency of small-sized fragments in experimental DNA distribution. The proposed model depends on two parameters describing the intensity and the shape of the background. It has been successfully validated against four series of experimental data of DNA distribution with increasing level of background.
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  • CFD simulations of horizontal ground heat exchangers: A comparison among different configurations

    Congedo, P. M.   Colangelo, G.   Starace, G.  

    This work deals with the efficiency and the energy behavior of Ground Source Heat Pumps (GSHPs) used for heating and cooling of buildings. In particular horizontal type heat exchangers have been investigated for different configurations, in order to evaluate the characteristics of these systems in the most common layouts and in different working conditions. The main results pointed out the heat fluxes transferred to and from the ground and the efficiency of the system. The calculations were made with the CFD code Fluent and the simulations covered one year of system operation, both in summer and winter for typical climate conditions of the South of Italy. The most important parameter for the heat transfer performance of the system resulted the thermal conductivity of the ground around the heat exchanger and the optimal ground type was that with the highest thermal conductivity (3 W/m K in the cases analyzed in this work). The choice of the velocity of the heat transfer fluid inside the tubes was another key factor. The depth of installation of the horizontal ground heat exchangers did not play an important role on the system performance. The helical heat exchanger arrangement resulted as the best performing one. (C) 2011 Elsevier Ltd. All rights reserved.
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  • Receptor-mediated endocytosis of alpha-2 macroglobulin by a glioma cell line

    Nori, S. L.   Businaro, R.   Fabrizi, C.   Moestrup, S. K.   Starace, G.   Fumagalli, L.   Lauro, G. M.  

    Previous experiments have shown that human neoplastic and embryonic glial cell lines synthesize and secrete in culture, alpha-2 macroglobulin (alpha-2M), a broad spectrum proteinase inhibitor present in serum and extracellular fluids. The present study was aimed to investigate the presence of alpha-2M receptors on glial cell membrane, since several nonneural cell types producing alpha-2M also express alpha-2M receptors. By flow cytometric analysis, immunofluorescence and immunoelectronmicroscopy techniques we demonstrate an alpha-2M receptor-related immunoreactivity on the plasma membrane of a human glioma cell line. Ultrastructural experiments reveal a close colocalization of immunoreactivities for alpha-2M and its receptor in clathrin-coated pits and vesicles, structures typically involved in receptor-mediated endocytic pathways.
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  • The hybrid method applied to the plate-finned tube evaporator geometry

    Starace, G.   Fiorentino, M.   Meleleo, B.   Risolo, C.  

    A procedure for the design and rating of plate-finned tube evaporator is proposed, to overcome limitations of both numerical and experiment based available present methods. The hybrid method allows to achieve high accuracy without incurring excessive computational cost and provides overall performance predictions starting from local analyses. The domain is divided into control volumes, where heat transfer is modeled by means of predictor equations obtained by known data. An iterative analytical method is used to find at each control volume the convergence between the heat transfer rates on both sides, and to obtain the distribution of wall temperature in the heat exchanger and the spatial distribution of the air mass flow rate. A case study is shown where in the first row the refrigerant completely evaporates, while this doesn't happen for the last one where the vapor quality at the outlet is 28% lower. (C) 2017 Elsevier Ltd and IIR. All rights reserved.
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  • Activated alpha2macroglobulin increases beta-amyloid (25-35)-induced toxicity in LAN5 human neuroblastoma cells

    Fabrizi, C.   Businaro, R.   Lauro, G. M.   Starace, G.   Fumagalli, L.  

    The presence of the alpha2macroglobulin receptor/low density lipoprotein receptor-related protein (alpha2Mr/ LRP) and its ligands alpha2macroglobulin (alpha2M), apoliprotein E, and plasminogen activators was detected in senile plaques of Alzheimer's disease (AD). To explore a possible role of alpha2M in neurodegenerative processes occurring in AD, we analyzed the effect of alpha2M on Abeta 25-35-induced neurotoxicity. Treatment of LAN5 human neuroblastoma cells with 10 muM beta-amyloid peptide fragment 25-35 (Abeta 25-35) for 72 h resulted in a 50% decrease in cell viability as determined by MTT incorporation and cell counts. The addition of alpha2M to the culture medium of these cells did not determine any effect, but when the activated form alpha2M* was used a dose-dependent decrease in cell viability was observed, the maximum effect being reached at 140 and 280 nM. Moreover, treatment of LAN5 cells with alpha2M* in combination with Abeta 25-35 increased the neurotoxicity of the amyloid peptide by 25%. This neurotoxic effect of alpha2M* seems to be related to its capability to bind and inactivate TGFbeta in the culture medium, since it was mimicked by a TGFbeta neutralizing antibody. A possible involvement of receptor-mediated endocytosis was ruled out, since alpha2M receptor is not present on LAN5, as revealed by RT-PCR and Western blotting experiments. The presence of alpha2M* in amyloid deposits of Alzheimer's disease has been recently reported and a possible impairment of LRP internalization processes has been hypothesized. Our data suggest that the local accumulation of alpha2M* in AD plaques may increase Abeta 25-35-induced neurotoxicity by neutralizing TGFbeta-mediated neuroprotective mechanisms.
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  • Interferon gamma up-regulates alpha-2 macroglobulin expression in human astrocytoma cells

    Fabrizi, C.   Colasanti, M.   Persichini, T.   Businaro, R.   Starace, G.   Lauro, G. M.  

    An established human astrocytoma cell line (T67) was shown to constitutively produce the proteinase inhibitor alpha-2macroglobulin (alpha-2M). Interferon gamma (IFN-gamma), a potent immunoregulatory lymphokine, was able to increase the synthesis of alpha-2M by these cells, as measured by ELISA on cell supernatants. The alpha-2M induction was also observed in other human glioma cell lines (T70 and ADF) and in human fetal astrocyte cultures following IFN-gamma treatment. In T67 cells this effect was dose-dependent and the maximum (2.7-fold increase) was obtained with 2000 U/ml of IFN-gamma. A corresponding enhanced alpha-2M mRNA accumulation was demonstrated by PCR and Northern blot techniques. Our results suggest an important role of alpha-2M during inflammatory and immune processes in the CNS. An increased release of alpha-2M following IFN-gamma stimulation may allow the removal of the bulk of proteases released at the site of inflammation, strengthening at the same time the antigen presentation processes.
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