TY - JOUR
AB - It is widely believed that the inflammatory events mediated by microglial activation contribute to several neurodegenerative processes. Alzheimer's disease, for example, is characterized by an accumulation of β-amyloid protein (Aβ) in neuritic plaques that are infiltrated by reactive microglia and astrocytes. Although Aβ and its fragment 25-35 exert a direct toxic effect on neurons, they also activate microglia. Microglial activation is accompanied by morphological changes, cell proliferation, and release of various cytokines and growth factors. A number of scientific reports suggest that the increased proliferation of microglial cells is dependent on ionic membrane currents and in particular on chloride conductances. An unusual chloride ion channel known to be associated with macrophage activation is the chloride intracellular channel-1 (CLIC1). Here we show that Aβ stimulation of neonatal rat microglia specifically leads to the increase in CLIC1 protein and to the functional expression of CLIC1 chloride conductance, both barely detectable on the plasma membrane of quiescent cells. CLIC1 protein expression in microglia increases after 24 hr of incubation with Aβ, simultaneously with the production of reactive nitrogen intermediates and of tumor necrosis factor-α (TNF-α). We demonstrate that reducing CLIC1 chloride conductance by a specific blocker [IAA-94 (R(+)-[(6,7-dichloro-2-cyclopentyl-2,3-dihydro-2-methyl-1-oxo-1H-inden-5yl)-oxy] acetic acid)] prevents neuronal apoptosis in neurons cocultured with Aβ-treated microglia. Furthermore, we show that small interfering RNAs used to knock down CLIC1 expression prevent TNF-α release induced by Aβ stimulation. These results provide a direct link between Aβ-induced microglial activation and CLIC1 functional expression.
AU - Gaia Novarino
AU - Fabrizi, Cinzia
AU - Tonini, Raffaella
AU - Denti, Michela A
AU - Malchiodi, Albedi F
AU - Lauro, Giuliana M
AU - Sacchetti, Benedetto
AU - Paradisi, Silvia
AU - Ferroni, Arnaldo
AU - Curmi, Paul M G
AU - Breit, Samuel N
AU - Mazzanti, Michele
ID - 2308
IS - 23
JF - Journal of Neuroscience
TI - Involvement of the intracellular ion channel CLIC1 in microglia-mediated β-amyloid-induced neurotoxicity
VL - 24
ER -
TY - JOUR
AB - The BMV conjecture for traces, which states that Tr exp(A - λB) is the Laplace transform of a positive measure, is shown to be equivalent to two other statements: (i) The polynomial λ → Tr(A + λB) p has only non-negative coefficients for all A, B ≥ 0, p ∈ ℕ and (ii) λ → Tr(A + λB)-p is the Laplace transform of a positive measure for A, B ≥ 0, p > 0.
AU - Lieb, Élliott H
AU - Robert Seiringer
ID - 2355
IS - 1-2
JF - Journal of Statistical Physics
TI - Equivalent forms of the Bessis-Moussa-Villani conjecture
VL - 115
ER -
TY - JOUR
AB - Recent experimental and theoretical work has shown that there are conditions in which a trapped, low-density Bose gas behaves like the one-dimensional delta-function Bose gas solved years ago by Lieb and Liniger. This is an intrinsically quantum-mechanical phenomenon because it is not necessary to have a trap width that is the size of an atom - as might have been supposed - but it suffices merely to have a trap width such that the energy gap for motion in the transverse direction is large compared to the energy associated with the motion along the trap. Up to now the theoretical arguments have been based on variational - perturbative ideas or numerical investigations. In contrast, this paper gives a rigorous proof of the one-dimensional behavior as far as the ground state energy and particle density are concerned. There are four parameters involved: the particle number, N, transverse and longitudinal dimensions of the trap, r and L, and the scattering length a of the interaction potential. Our main result is that if r/L → 0 and N → ∞ the ground state energy and density can be obtained by minimizing a one-dimensional density functional involving the Lieb-Liniger energy density with coupling constant ∼ a/r 2. This density functional simplifies in various limiting cases and we identify five asymptotic parameter regions altogether. Three of these, corresponding to the weak coupling regime, can also be obtained as limits of a three-dimensional Gross-Pitaevskii theory. We also show that Bose-Einstein condensation in the ground state persists in a part of this regime. In the strong coupling regime the longitudinal motion of the particles is strongly correlated. The Gross-Pitaevskii description is not valid in this regime and new mathematical methods come into play.
AU - Lieb, Élliott H
AU - Robert Seiringer
AU - Yngvason, Jakob
ID - 2356
IS - 2
JF - Communications in Mathematical Physics
TI - One-dimensional behavior of dilute, trapped Bose gases
VL - 244
ER -
TY - JOUR
AB - An optical lattice model developed that is similar to the Bose-Hubbard model to describe the transition between Bose-Einstein condensation (BEC) and a Mott insulator state was analyzed. It was found that the system was a hard core lattice gas at half of the maximum density and the optical lattice was modeled by a periodic potential of strength λ. It was also observed that the interparticle interaction was essential for this transition that occurred even in the ground state. The results show that all the essential features could be proved rigorously such as the existence of BEC for small λ and its suppression for a large λ.
AU - Aizenman, Michael
AU - Lieb, Élliott H
AU - Robert Seiringer
AU - Solovej, Jan P
AU - Yngvason, Jakob
ID - 2360
IS - 2
JF - Physical Review A - Atomic, Molecular, and Optical Physics
TI - Bose-Einstein quantum phase transition in an optical lattice model
VL - 70
ER -
TY - CHAP
AU - Lovász, László
AU - Vesztergombi, Katalin
AU - Uli Wagner
AU - Welzl, Emo
ED - Pach, János
ID - 2417
T2 - Towards a Theory of Geometric Graphs
TI - Convex quadrilaterals and k-sets
VL - 342
ER -
TY - JOUR
AB - A finite set N ⊂ Rd is a weak ε-net for an n-point set X ⊂ Rd (with respect to convex sets) if N intersects every convex set K with |K ∩ X| ≥ εn. We give an alternative, and arguably simpler, proof of the fact, first shown by Chazelle et al., that every point set X in Rd admits a weak ε-net of cardinality O(ε-dpolylog(1/ε)). Moreover, for a number of special point sets (e.g., for points on the moment curve), our method gives substantially better bounds. The construction yields an algorithm to construct such weak ε-nets in time O(n ln(1/ε)).
AU - Matoušek, Jiří
AU - Uli Wagner
ID - 2425
IS - 2
JF - Discrete & Computational Geometry
TI - New constructions of weak ε-nets
VL - 32
ER -
TY - JOUR
AB - We introduce the adaptive neighborhood graph as a data structure for modeling a smooth manifold M embedded in some Euclidean space ℝ d. We assume that M is known to us only through a finite sample P ⊂ M, as is often the case in applications. The adaptive neighborhood graph is a geometric graph on P. Its complexity is at most min{2O(k)n, n2}, where n = P and k = dim M, as opposed to the n[d/2] complexity of the Delaunay triangulation, which is often used to model manifolds. We prove that we can correctly infer the connected components and the dimension of M from the adaptive neighborhood graph provided a certain standard sampling condition is fulfilled. The running time of the dimension detection algorithm is d20(k7 log k) for each connected component of M. If the dimension is considered constant, this is a constant-time operation, and the adaptive neighborhood graph is of linear size. Moreover, the exponential dependence of the constants is only on the intrinsic dimension k, not on the ambient dimension d. This is of particular interest if the co-dimension is high, i.e., if k is much smaller than d, as is the case in many applications. The adaptive neighborhood graph also allows us to approximate the geodesic distances between the points in P.
AU - Giesen, Joachim
AU - Uli Wagner
ID - 2426
IS - 2
JF - Discrete & Computational Geometry
TI - Shape dimension and intrinsic metric from samples of manifolds
VL - 32
ER -
TY - GEN
AU - Sauer, Michael
AU - Friml, Jirí
ID - 2461
IS - 23
T2 - Development
TI - The Matryoshka dolls of plant polarity
VL - 131
ER -
TY - GEN
AU - Momiyama, Akiko
AU - Ryuichi Shigemoto
ID - 2636
IS - 3 Suppl
T2 - Tanpakushitsu kakusan koso Protein nucleic acid enzyme
TI - Function and distribution of glutamate receptors in the central synapses
VL - 49
ER -
TY - JOUR
AB - Among various types of low- and high-threshold calcium channels, the high voltage-activated P/Q-type channel is the most abundant in the cerebellum. These P/Q-type channels are involved in the regulation of neurotransmitter release and in the integration of dendritic inputs. We used an antibody specific for the α1A subunit of the P/Q-type channel in quantitative pre-embedding immunogold labelling combined with three-dimensional reconstruction to reveal the subcellular distribution of pre- and postsynaptic P/Q-type channels in the rat cerebellum. At the light microscopic level, immunoreactivity for the α1A protein was prevalent in the molecular layer, whereas immunostaining was moderate in the somata of Purkinje cells and weak in the granule cell layer. At the electron microscopic level, the most intense Immunoreactivity for the α1A subunit was found in the presynaptic active zone of parallel fibre varicosities. The dendritic spines of Purkinje cells were also strongly labelled with the highest density of immunoparticles detected within 180 nm from the edge of the asymmetrical parallel fibre-Purkinje cell synapses. By contrast, the immunolabelling was sparse in climbing fibre varicosities and axon terminals of GABAergic cells, and weak and diffuse in dendritic shafts of Purkinje cells. The association of the α1A subunit with the glutamatergic parallel fibre-Purkinje cell synapses suggests that presynaptic channels have a major role in the mediation of excitatory neurotransmission, whereas postsynaptic channels are likely to be involved in depolarization-induced generation of local calcium transients in Purkinje cells.
AU - Kulik, Ákos
AU - Nakadate, Kazuhiko
AU - Hagiwara, Akari
AU - Fukazawa, Yugo
AU - Luján, Rafael
AU - Saito, Hiromitsu
AU - Suzuki, Noboru
AU - Futatsugi, Akira
AU - Mikoshiba, Katsuhiko
AU - Frotscher, Michael
AU - Ryuichi Shigemoto
ID - 2638
IS - 8
JF - European Journal of Neuroscience
TI - Immunocytochemical localization of the α1A subunit of the P/Q-type calcium channel in the rat cerebellum
VL - 19
ER -