472 research outputs found

    Functional Evaluation of AMD-Associated Risk Variants of Complement Factor B

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    Purpose: The 32W and 32Q variants of complement factor B (CFB) are associated with reduced risk of developing neovascular age-related macular degeneration (AMD) compared with the common 32R allele. The objective of this study was to determine if the most protective R32Q variant affects the neovascular process in a manner consistent with the reported reduced disease association. Methods: The 32R, 32W, and 32Q human CFB variants were expressed in human embryonic kidney 293T cells and purified from culture supernatant. The ex vivo mouse fetal metatarsal explant model was used to investigate the effect of these three human CFB variants on angiogenesis. Metatarsal bones were isolated from mouse embryos and cultured in the presence of the three CFB variants, and angiogenesis was measured following immunostaining of fixed samples. ELISAs were used to quantify C3 and VEGF protein levels in metatarsal culture and quantitative PCR to measure Cfb, C3, and Vegf expression. Results: We show here that the three CFB variants have different biological activities in the mouse metatarsal assay, with CFBR32 exhibiting significantly greater angiogenic activity than CFBQ32 or CFBW32, which were broadly similar. We also observed differences in macrophage phenotype with these two variants that may contribute to their activities in this experimental model. Conclusions: We have demonstrated that the biological activities of CFBR32, CFBW32, and CFBQ32 are consistent with their AMD risk association, and we provide functional evidence of roles for these variants in angiogenesis that may be relevant to the pathogenesis of the neovascular form of AMD

    Study of tributary inflows in Lake Iseo with a rotating physical model

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    The influence of Coriolis force on the currents of large lakes is well acknowledged; very few contributions, however, investigate this aspect in medium-size lakes where its relevance could be questionable. In order to study the area of influence of the two major tributary rivers in Lake Iseo, a rotating vertically distorted physical model of the northern part of this lake was prepared and used, respecting both Froude and Rossby similarity. The model has a horizontal length scale factor of 8000 and a vertical scale factor of 500 and was used both in homogeneous and in thermally stratified conditions. We explored the pattern of water circulation in front of the entrance mouth for dif- ferent hydrologic scenarios at the beginning of spring and in summer. We neglected the influence of winds. The primary purposes of the model were twofold: i) to increase our level of knowledge of the hydrodynamics of Lake Iseo by verifying the occurrence of dynamical effects related to the Earth’s rotation on the plume of the two tributaries that enter the northern part of the lake and ii) to identify the areas of the lake that can be directly influenced by the tributaries’ waters, in order to provide guidance on water quality monitoring in zones of relevant environmental and touristic value. The results of the physical model confirm the relevant role played by the Coriolis force in the northern part of the lake. Under ordinary flow conditions, the model shows a systematic deflection of the inflowing waters towards the western shore of the lake. The inflow triggers a clockwise gyre within the Lovere bay, to the West of the inflow, and a slow counter-clockwise gyre, to the East of the inflow, that returns water towards the river mouth along the eastern shore. For discharges with higher return period, when only the contribution by Oglio River is relevant, the effect of the Earth’s rotation weakens in the entrance zone and the plume has a more rectilinear pattern, whilst in the far field the current driven by the inflows keeps moving along the western shore. On the basis of these results one could expect that the north-western part of the lake between Castro and Lovere, although not aligned with the tributaries’ axes, is more sensitive to accumulation effects related to river-borne pollution. The results obtained with the physical model are critically compared with data obtained from different sources: the trajectory of a lagrangian drogue; a map of reflectivity data from the lake floor; a map of water turbidity at the intrusion depth. The findings are also confirmed by the results of a 3D numerical model of the lake

    A dual defensive role of CIITA against retroviral infections

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    We describe how CIITA exerts a dual role against retroviral infection. The first, classical role is the upregulation of MHC class II expression and thus the capacity to present viral antigens to CD4+ T cells. The other, evolutionary new and fundamental role is to inhibit viral replication by blocking specifically the function of the viral transactivators. HIV-1 Tat is inhibited through the competition for cyclin T1 of the P-TEFb complex, whereas HTLV-2 Tax-2 is inhibited through a concerted action which may increase the binding affinity of the CIITA-NFY complex for Tax-2, displacing it from the viral LTR promoter. As expected, two distint sequences in the N-term region of CIITA mediate the inhibitory action on Tat and Tax-2, respectively. Of note, Tax-1 from HTLV-1 seems also to be inhibited by the same sequence that inhibits HTLV-2 Tax-2. Interestingly, only those CIITA fragments containing the minimal inhibitory domains that localize into the nucleus could exert an effective suppressive action. Taken together, our results indicate that CIITA is an extant molecular tool endowed with distinct evolving functions against retroviruses. These distinct properties of CIITA will shed new light on the molecular mechanisms of adaptive coevolution of hosts and pathogens and may be exploited to envisage novel therapeutic strategies aimed at counteracting retroviral infections

    Evidence from field measurements and satellite imaging of impact of Earth rotation on Lake Iseo chemistry

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    During an initial field survey in 2012, we observed an unexpected asymmetry of dissolved oxygen distribution between the western and eastern side in northern Lake Iseo. Motivated by this apparent anomaly, we conducted a detailed field investigation, and we used a physical model of the northern part of the lake to understand the in- fluences that might affect the distribution of material in the northern section of the lake. These investigations sug- gested that the Earth's rotation has significant influence on the inflow of the lake's two main tributaries. In order to further crosscheck the validity of these results, we conducted a careful analysis at a synoptic scale using images acquired during thermally unstratified periods by Landsat-8 and Sentinel-2 satellites. We retrieved and post- processed a large set of images, providing conclusive evidence of the role exerted by the Earth's rotation on pol- lutant transport in Lake Iseo and of the greater environmental vulnerability of the north-west shore of this lake, where important settlements are located. Our study confirms the necessity for three-dimensional hydrodynamic models including Coriolis effect in order to effectively predict local impacts of inflows on nearshore water quality of medium-sized elongated lakes of similar scale to Lake Iseo

    Leucine-rich alpha-2-glycoprotein 1 (LRG1) as a novel ADC target

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    Leucine-rich alpha-2-glycoprotein 1 (LRG1) is present abundantly in the microenvironment of many tumours where it contributes to vascular dysfunction, which impedes the delivery of therapeutics. In this work we demonstrate that LRG1 is predominantly a non-internalising protein. We report the development of a novel antibody–drug conjugate (ADC) comprising the anti-LRG1 hinge-stabilised IgG4 monoclonal antibody Magacizumab coupled to the anti-mitotic payload monomethyl auristatin E (MMAE) via a cleavable dipeptide linker using the site-selective disulfide rebridging dibromopyridazinedione (diBrPD) scaffold. It is demonstrated that this ADC retains binding post-modification, is stable in serum and effective in in vitro cell studies. We show that the extracellular LRG1-targeting ADC provides an increase in survival in vivo when compared against antibody alone and similar anti-tumour activity when compared against standard chemotherapy, but without undesired side-effects. LRG1 targeting through this ADC presents a novel and effective proof-of-concept en route to improving the efficacy of cancer therapeutics

    Identification of a novel spliced variant of the SYT gene expressed in normal tissues and in synovial sarcoma

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    Synovial sarcoma (SS) is cytogenetically characterized by the translocation t(X;18)(p11.2-q11.2) generating a fusion between the SYT gene on chromosome 18 and one member of the SSX family gene (SSX1; SSX2; SSX4) on chromosome X. Here, we report for the first time that 2 forms of SYT mRNA are present in both normal tissues and SSs. By amplifying the full-length SYT cDNA of two SSs, we detected 2 bands, here designated N-SYT and I-SYT. The latter, previously undescribed, contains an in-frame insertion of 93 bp. Its sequencing revealed a 100% homology with the mouse SYT gene. These two SYT forms were present, although in different amounts, in all human normal tissues examined, including kidney, stomach, lung, colon, liver and synovia. Coexistence of N-SYT and I-SYT (both fused with SSX) was detected in a series of 59 SSs (35 monophasic and 24 biphasic) and in a SS cell line. A preliminary analysis of the differential expression levels of N-SYT and I-SYT in SSs revealed that the latter was consistently overexpressed, suggesting a role in SS pathogenesis. © 2001 Cancer Research Campaign http://www.bjcancer.co
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