466 research outputs found
Schwann Cell Autocrine and Paracrine Regulatory Mechanisms, Mediated by Allopregnanolone and BDNF, Modulate PKCε in Peripheral Sensory Neurons
Protein kinase type C-\u3b5 (PKC\u3b5) plays important roles in the sensitization of primary afferent nociceptors, such as ion channel phosphorylation, that in turn promotes mechanical hyperalgesia and pain chronification. In these neurons, PKC\u3b5 is modulated through the local release of mediators by the surrounding Schwann cells (SCs). The progesterone metabolite allopregnanolone (ALLO) is endogenously synthesized by SCs, whereas it has proven to be a crucial mediator of neuron-glia interaction in peripheral nerve fibers. Biomolecular and pharmacological studies on rat primary SCs and dorsal root ganglia (DRG) neuronal cultures were aimed at investigating the hypothesis that ALLO modulates neuronal PKC\u3b5, playing a role in peripheral nociception. We found that SCs tonically release ALLO, which, in turn, autocrinally upregulated the synthesis of the growth factor brain-derived neurotrophic factor (BDNF). Subsequently, glial BDNF paracrinally activates PKC\u3b5 via trkB in DRG sensory neurons. Herein, we report a novel mechanism of SCs-neuron cross-talk in the peripheral nervous system, highlighting a key role of ALLO and BDNF in nociceptor sensitization. These findings emphasize promising targets for inhibiting the development and chronification of neuropathic pain
Fast Diffusion Process in Quenched hcp Dilute Solid He-He Mixture
The study of phase structure of dilute He - He solid mixture of
different quality is performed by spin echo NMR technique. The diffusion
coefficient is determined for each coexistent phase. Two diffusion processes
are observed in rapidly quenched (non-equilibrium) hcp samples: the first
process has a diffusion coefficient corresponding to hcp phase, the second one
has huge diffusion coefficient corresponding to liquid phase. That is evidence
of liquid-like inclusions formation during fast crystal growing. It is
established that these inclusions disappear in equilibrium crystals after
careful annealing.Comment: 7 pages, 3 figures, QFS200
NaV1.7 and pain: contribution of peripheral nerves
The sodium channel NaV1.7 contributes to action potential generation and propagation. Loss-of-function mutations in patients lead to congenital indifference to pain, though it remains unclear where on the way from sensory terminals to CNS the signalling is disrupted. We confirm that conditional deletion of NaV1.7 in advillin expressing sensory neurons leads to impaired heat and mechanical nociception in behavioural tests. With single-fiber recordings from isolated skin we found (1) a significantly lower prevalence of heat responsiveness to in normally mechanosensitive C-fibers, although (2) the rare heat responses appeared quite vigorous and (3) heat-induced CGRP release was normal. In biophysical respects, while electrical excitability, rheobase and chronaxy were normal (4) axonal conduction velocity was 20% slower than in congenic wildtype mice (5) and when challenged with double pulses (< 100 ms interval), the second action potential showed more pronounced latency increase (6). Upon prolonged electrical stimulation at 2 Hz, (7) activity-dependent slowing of nerve fiber conduction was markedly less and (8) was less likely to result in conduction failure of the mutant single-fibers. Finally, recording of compound action potentials from the whole saphenous nerve confirmed slower conduction and less activity-dependent slowing as well as the functional absence of a large subpopulation of C-fibers (9) in conditional Nav1.7 knock-outs. In conclusion, the clear deficits in somatic primary afferent functions shown in our study may be complemented by previously reported synaptic dysfunction and opioidergic inhibition, together accounting for the complete insensitivity to pain in the human mutants lacking Nav1.7
Primary accumulation in the Soviet transition
The Soviet background to the idea of primary socialist accumulation is presented. The mobilisation of labour power and of products into public sector investment from outside are shown to have been the two original forms of the concept. In Soviet primary accumulation the mobilisation of labour power was apparently more decisive than the mobilisation of products. The primary accumulation process had both intended and unintended results. Intended results included bringing most of the economy into the public sector, and industrialisation of the economy as a whole. Unintended results included substantial economic losses, and the proliferation of coercive institutions damaging to attainment of the ultimate goal - the building of a communist society
Bose-Einstein condensates in a one-dimensional double square well: Analytical solutions of the Nonlinear Schr\"odinger equation and tunneling splittings
We present a representative set of analytic stationary state solutions of the
Nonlinear Schr\"odinger equation for a symmetric double square well potential
for both attractive and repulsive nonlinearity. In addition to the usual
symmetry preserving even and odd states, nonlinearity introduces quite exotic
symmetry breaking solutions - among them are trains of solitons with different
number and sizes of density lumps in the two wells. We use the symmetry
breaking localized solutions to form macroscopic quantum superpositions states
and explore a simple model for the exponentially small tunneling splitting.Comment: 11 pages, 11 figures, revised version, typos and references correcte
Determination of the neutron electric form factor in quasielastic scattering of polarized electrons from polarized 3He
We report a measurement of the asymmetry in spin-dependent quasielastic scattering of longitudinally polarized electrons from a polarized 3He gas target. The asymmetry is measured at kinematics sensitive to the transverse-longitudinal response function RTL(Q2,ω). The value of the neutron electric form factor GEn(Q2=0.16 (GeV/c2))=+0.070±0.100±0.035 is extracted from the asymmetry using a Faddeev calculation of the 3He wave function
Measurement of the neutron magnetic form factor from inclusive quasielastic scattering of polarized electrons from polarized 3He
We report a measurement of the asymmetry in spin-dependent quasielastic scattering of longitudinally polarized electrons from a polarized 3He target. The neutron magnetic form factor GMn has been extracted from the measured asymmetry based on recent PWIA calculations using spin-dependent spectral functions. Our determination of GMn at Q2=0.19 (GeV/c)2 agrees with the dipole parametrization. This experiment represents the first measurement of the neutron magnetic form factor using spin-dependent electron scattering
Search for supersymmetry with a dominant R-parity violating LQDbar couplings in e+e- collisions at centre-of-mass energies of 130GeV to 172 GeV
A search for pair-production of supersymmetric particles under the assumption
that R-parity is violated via a dominant LQDbar coupling has been performed
using the data collected by ALEPH at centre-of-mass energies of 130-172 GeV.
The observed candidate events in the data are in agreement with the Standard
Model expectation. This result is translated into lower limits on the masses of
charginos, neutralinos, sleptons, sneutrinos and squarks. For instance, for
m_0=500 GeV/c^2 and tan(beta)=sqrt(2) charginos with masses smaller than 81
GeV/c^2 and neutralinos with masses smaller than 29 GeV/c^2 are excluded at the
95% confidence level for any generation structure of the LQDbar coupling.Comment: 32 pages, 30 figure
Search for the glueball candidates f0(1500) and fJ(1710) in gamma gamma collisions
Data taken with the ALEPH detector at LEP1 have been used to search for gamma
gamma production of the glueball candidates f0(1500) and fJ(1710) via their
decay to pi+pi-. No signal is observed and upper limits to the product of gamma
gamma width and pi+pi- branching ratio of the f0(1500) and the fJ(1710) have
been measured to be Gamma_(gamma gamma -> f0(1500)). BR(f0(1500)->pi+pi-) <
0.31 keV and Gamma_(gamma gamma -> fJ(1710)). BR(fJ(1710)->pi+pi-) < 0.55 keV
at 95% confidence level.Comment: 10 pages, 3 figure
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