794 research outputs found

    Label-free morpho-molecular phenotyping of living cancer cells by combined Raman spectroscopy and phase tomography

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    Accurate, rapid and non-invasive cancer cell phenotyping is a pressing concern across the life sciences, as standard immuno-chemical imaging and omics require extended sample manipulation. Here we combine Raman micro-spectroscopy and phase tomography to achieve label-free morpho-molecular profiling of human colon cancer cells, following the adenoma, carcinoma, and metastasis disease progression, in living and unperturbed conditions. We describe how to decode and interpret quantitative chemical and co-registered morphological cell traits from Raman fingerprint spectra and refractive index tomograms. Our multimodal imaging strategy rapidly distinguishes cancer phenotypes, limiting observations to a low number of pristine cells in culture. This synergistic dataset allows us to study independent or correlated information in spectral and tomographic maps, and how it benefits cell type inference. This method is a valuable asset in biomedical research, particularly when biological material is in short supply, and it holds the potential for non-invasive monitoring of cancer progression in living organisms.Label-free morpho-molecular phenotyping of living cancer cells is achieved combining Raman spectroscopy and Phase Tomography. This quick all-optical method is effective on non-manipulated cells in standard culture conditions with a small sample siz

    Hypoxia- and Postirradiation reoxygenation-induced HMHA1/ARHGAP45 expression contributes to cancer cell invasion in a HIF-dependent manner

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    Background: Cancer cells in severely hypoxic regions have been reported to invade towards tumour blood vessels after surviving radiotherapy in a postirradiation reoxygenation- and hypoxia-inducible factor (HIF)-dependent manner and cause recurrence. However, how HIF induces invasiveness of irradiated and reoxygenated cancer cells remains unclear. Methods: Here, we identified human minor histocompatibility antigen 1 (HMHA1), which has been suggested to function in cytoskeleton dynamics and cellular motility, as a responsible factor and elucidated its mechanism of action using molecular and cellular biology techniques. Results: HMHA1 expression was found to be induced at the transcription initiation level in a HIF-dependent manner under hypoxia. Boyden chamber invasion assay revealed that the induction of HMHA1 expression is required for the increase in invasion of hypoxic cancer cells. Reoxygenation treatment after ionising radiation in vitro that mimics dynamic changes of a microenvironment in hypoxic regions of tumour tissues after radiation therapy further enhanced HMHA1 expression and invasive potential of HMHA1 wildtype cancer cells in ROS- and HIF-dependent manners, but not of HMHA1 knockout cells. Conclusion: These results together provide insights into a potential molecular mechanism of the acquisition of invasiveness by hypoxic cancer cells after radiotherapy via the activation of the ROS/HIF/HMHA1 axis

    Local modulation of the Wnt/β‐catenin and bone morphogenic protein (BMP) pathways recapitulates rib defects analogous to cerebro‐costo‐mandibular syndrome

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    Ribs are seldom affected by developmental disorders, however, multiple defects in rib structure are observed in the spliceosomal disease cerebro‐costo‐mandibular syndrome (CCMS). These defects include rib gaps, found in the posterior part of the costal shaft in multiple ribs, as well as missing ribs, shortened ribs and abnormal costotransverse articulations, which result in inadequate ventilation at birth and high perinatal mortality. The genetic mechanism of CCMS is a loss‐of‐function mutation in SNRPB, a component of the major spliceosome, and knockdown of this gene in vitro affects the activity of the Wnt/β‐catenin and bone morphogenic protein (BMP) pathways. The aim of the present study was to investigate whether altering these pathways in vivo can recapitulate rib gaps and other rib abnormalities in the model animal. Chick embryos were implanted with beads soaked in Wnt/β‐catenin and BMP pathway modulators during somitogenesis, and incubated until the ribs were formed. Some embryos were harvested in the preceding days for analysis of the chondrogenic marker Sox9, to determine whether pathway modulation affected somite patterning or chondrogenesis. Wnt/β‐catenin inhibition manifested characteristic rib phenotypes seen in CCMS, including rib gaps (P < 0.05) and missing ribs (P < 0.05). BMP pathway activation did not cause rib gaps but yielded missing rib (P < 0.01) and shortened rib phenotypes (P < 0.05). A strong association with vertebral phenotypes was also noted with BMP4 (P < 0.001), including scoliosis (P < 0.05), a feature associated with CCMS. Reduced expression of Sox9 was detected with Wnt/β‐catenin inhibition, indicating that inhibition of chondrogenesis precipitated the rib defects in the presence of Wnt/β‐catenin inhibitors. BMP pathway activators also reduced Sox9 expression, indicating an interruption of somite patterning in the manifestation of rib defects with BMP4. The present study demonstrates that local inhibition of the Wnt/β‐catenin and activation of the BMP pathway can recapitulate rib defects, such as those observed in CCMS. The balance of Wnt/β‐catenin and BMP in the somite is vital for correct rib morphogenesis, and alteration of the activity of these two pathways in CCMS may perturb this balance during somite patterning, leading to the observed rib defects

    Superconductivity in the Ferroquadrupolar State in the Quadrupolar Kondo Lattice PrTi2_2Al20_{20}

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    The cubic compound PrTi2_2Al20_{20} is a quadrupolar Kondo lattice system that exhibits quadrupolar ordering due to the non-Kramers Γ3\Gamma_3 ground doublet and has strong hybridization between 4f4f and conduction electrons. Our study using high-purity single crystal reveals that PrTi2_2Al20_{20} exhibits type-II superconductivity at Tc=200T_{\rm c} = 200 mK in the nonmagnetic ferroquadrupolar state. The superconducting critical temperature and field phase diagram suggests moderately enhanced effective mass of m/m016m^*/m_0 \sim 16

    Exclusion of integrins from CNS axons is regulated by Arf6 activation and the AIS.

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    Integrins are adhesion and survival molecules involved in axon growth during CNS development, as well as axon regeneration after injury in the peripheral nervous system (PNS). Adult CNS axons do not regenerate after injury, partly due to a low intrinsic growth capacity. We have previously studied the role of integrins in axon growth in PNS axons; in the present study, we investigate whether integrin mechanisms involved in PNS regeneration may be altered or lacking from mature CNS axons by studying maturing CNS neurons in vitro. In rat cortical neurons, we find that integrins are present in axons during initial growth but later become restricted to the somato-dendritic domain. We investigated how this occurs and whether it can be altered to enhance axonal growth potential. We find a developmental change in integrin trafficking; transport becomes predominantly retrograde throughout axons, but not dendrites, as neurons mature. The directionality of transport is controlled through the activation state of ARF6, with developmental upregulation of the ARF6 GEF ARNO enhancing retrograde transport. Lowering ARF6 activity in mature neurons restores anterograde integrin flow, allows transport into axons, and increases axon growth. In addition, we found that the axon initial segment is partly responsible for exclusion of integrins and removal of this structure allows integrins into axons. Changing posttranslational modifications of tubulin with taxol also allows integrins into the proximal axon. The experiments suggest that the developmental loss of regenerative ability in CNS axons is due to exclusion of growth-related molecules due to changes in trafficking.The authors thank Dr. Matthew N. Rasband for kindly providing the adenoviruses for ankG silencing experiment and Dr. Juan Bonifacino for AP-1 constructs. We also thank Menghon Cheah for his assistance. We acknowledge funding from the Medical Research Council, the Christopher and Dana Reeve Foundation, EU Framework 7 Project Plasticise, the European Research Council, the John and Lucille van Geest Foundation, and the NIHR Cambridge Biomedical Research Centre.This is the final version of the article. It first appeared from the Society for Neuroscience via http://dx.doi.org/10.1523/JNEUROSCI.2850-14.201

    Search for the Invisible Decay of Neutrons with KamLAND

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    The Kamioka Liquid scintillator Anti-Neutrino Detector (KamLAND) is used in a search for single neutron or two neutron intra-nuclear disappearance that would produce holes in the s\it{s}-shell energy level of 12^{12}C nuclei. Such holes could be created as a result of nucleon decay into invisible modes (invinv), e.g. n3νn \to 3\nu or nn2νnn \to 2\nu. The de-excitation of the corresponding daughter nucleus results in a sequence of space and time correlated events observable in the liquid scintillator detector. We report on new limits for one- and two-neutron disappearance: τ(ninv)>5.8×1029\tau(n\to inv)> 5.8\times 10^{29} years and τ(nninv)>1.4×1030\tau (nn \to inv)> 1.4 \times 10^{30} years at 90% CL. These results represent an improvement of factors of \sim3 and >104>10^4 over previous experiments.Comment: 5 pages, 3 figure

    Carriers of Loss-of-Function Mutations in ABCA1 Display Pancreatic β-Cell Dysfunction

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    OBJECTIVE: Abnormal cellular cholesterol handling in islets may contribute to beta-cell dysfunction in type 2 diabetes. beta-Cell deficiency for the ATP binding cassette transporter A1 (ABCA1), which mediates the efflux of cellular cholesterol, leads to altered intracellular cholesterol homeostasis and impaired insulin secretion in mice. We aimed to assess the impact of ABCA1 dysfunction on glucose homeostasis in humans. RESEARCH DESIGN AND METHODS: In heterozygous carriers of disruptive mutations in ABCA1 and family-based noncarriers of similar age, sex, and BMI, we performed oral glucose tolerance tests (OGTTs) (n = 15 vs. 14) and hyperglycemic clamps (n = 8 vs. 8). RESULTS: HDL cholesterol levels in carriers were less than half those in noncarriers, but LDL cholesterol levels did not differ. Although fasting plasma glucose was similar between groups, glucose curves after an OGTT were mildly higher in carriers than in noncarriers. During hyperglycemic clamps, carriers demonstrated lower first-phase insulin secretion than noncarriers but no difference in insulin sensitivity. The disposition index (a measure of beta-cell function adjusted for insulin sensitivity) of the carriers was significantly reduced in ABCA1 heterozygotes. CONCLUSIONS: Carriers of loss-of-function mutations in ABCA1 show impaired insulin secretion without insulin resistance. Our data provide evidence that ABCA1 is important for normal beta-cell function in human

    Measurement of Neutrino Oscillation with KamLAND: Evidence of Spectral Distortion

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    We present results of a study of neutrino oscillation based on a 766 ton-year exposure of KamLAND to reactor anti-neutrinos. We observe 258 \nuebar\ candidate events with energies above 3.4 MeV compared to 365.2 events expected in the absence of neutrino oscillation. Accounting for 17.8 expected background events, the statistical significance for reactor \nuebar disappearance is 99.998%. The observed energy spectrum disagrees with the expected spectral shape in the absence of neutrino oscillation at 99.6% significance and prefers the distortion expected from \nuebar oscillation effects. A two-neutrino oscillation analysis of the KamLAND data gives \DeltaMSq = 7.90.5+0.6×105^{+0.6}_{-0.5}\times10^{-5} eV2^2. A global analysis of data from KamLAND and solar neutrino experiments yields \DeltaMSq = 7.90.5+0.6×105^{+0.6}_{-0.5}\times10^{-5} eV2^2 and \ThetaParam = 0.400.07+0.10^{+0.10}_{-0.07}, the most precise determination to date.Comment: 5 pages, 4 figures; submitted to Phys.Rev.Letter

    First Results from KamLAND: Evidence for Reactor Anti-Neutrino Disappearance

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    KamLAND has been used to measure the flux of νˉe\bar{\nu}_e's from distant nuclear reactors. In an exposure of 162 ton\cdotyr (145.1 days) the ratio of the number of observed inverse β\beta-decay events to the expected number of events without disappearance is 0.611±0.085(stat)±0.041(syst)0.611\pm 0.085 {\rm (stat)} \pm 0.041 {\rm (syst)} for νˉe\bar{\nu}_e energies >> 3.4 MeV. The deficit of events is inconsistent with the expected rate for standard νˉe\bar{\nu}_e propagation at the 99.95% confidence level. In the context of two-flavor neutrino oscillations with CPT invariance, these results exclude all oscillation solutions but the `Large Mixing Angle' solution to the solar neutrino problem using reactor νˉe\bar{\nu}_e sources.Comment: 6 pages, 6 figure
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