146 research outputs found
Neurological Dysfunction in Coeliac Disease and Non-Coeliac Gluten Sensitivity
OBJECTIVES: Non-coeliac gluten sensitivity (NCGS) refers to patients with primarily gastrointestinal symptoms
without enteropathy that symptomatically benefi t from gluten-free diet (GFD). Little is known about
its pathophysiology, propensity to neurological manifestations, and if these differ from patients with
coeliac disease (CD). We investigated the clinical and immunological characteristics of patients
presenting with neurological manifestations with CD and those with NCGS.
METHODS: We compared clinical, neurophysiological, and imaging data of patients with CD and NCGS
presenting with neurological dysfunction assessed and followed up regularly over a period of
20 years.
RESULTS: Out of 700 patients, 562 were included. Exclusion criteria included no bowel biopsy to confi rm
CD, no HLA type available, and failure to adhere to GFD. All patients presented with neurological
dysfunction and had circulating anti-gliadin antibodies. Out of 562 patients, 228 (41%) had
evidence of enteropathy (Group 1, CD) and 334 (59%) did not (Group 2, NCGS). The most common
neurological manifestations were cerebellar ataxia, peripheral neuropathy, and encephalopathy. There
was a greater proportion of patients with encephalopathy in Group 1 and with a greater proportion
of neuropathy in Group 2. The severity of ataxia did not differ between the two groups. Patients in
Group 1 had more severe neuropathy. All patients from both groups responded to gluten-free diet.
Anti-tissue transglutaminase (TG2) antibodies were found in 91% of patients in Group 1 and in
29% of patients in Group 2. Comparison between those patients in Group 2 with HLA-DQ2/DQ8 and
those without as well as those with positive TG2 compared with those with negative TG2 antibodies
identifi ed no differences within these subgroups. Serological positivity for TG6 antibodies was similar
in the two groups (67 and 60%).
CONCLUSIONS: The neurological manifestations of CD and NCGS are similar and equally responsive to a GFD
suggestive of common pathophysiological mechanisms
Measurement of the W+W-gamma Cross Section and Direct Limits on Anomalous Quartic Gauge Boson Couplings at LEP
The process e+e- -> W+W-gamma is analysed using the data collected with the
L3 detector at LEP at a centre-of-mass energy of 188.6GeV, corresponding to an
integrated luminosity of 176.8pb^-1. Based on a sample of 42 selected W+W-
candidates containing an isolated hard photon, the W+W-gamma cross section,
defined within phase-space cuts, is measured to be: sigma_WWgamma = 290 +/- 80
+/- 16 fb, consistent with the Standard Model expectation. Including the
process e+e- -> nu nu gamma gamma, limits are derived on anomalous
contributions to the Standard Model quartic vertices W+W- gamma gamma and W+W-Z
gamma at 95% CL: -0.043 GeV^-2 < a_0/Lambda^2 < 0.043 GeV^-2 0.08 GeV^-2 <
a_c/Lambda^2 < 0.13 GeV^-2 0.41 GeV^-2 < a_n/Lambda^2 < 0.37 GeV^-2
Production of Single W Bosons at \sqrt{s}=189 GeV and Measurement of WWgamma Gauge Couplings
Single W boson production in electron-positron collisions is studied with the
L3 detector at LEP. The data sample collected at a centre-of-mass energy of
\sqrt{s} = 188.7GeV corresponds to an integrated luminosity of 176.4pb^-1.
Events with a single energetic lepton or two acoplanar hadronic jets are
selected. Within phase-space cuts, the total cross-section is measured to be
0.53 +/- 0.12 +/- 0.03 pb, consistent with the Standard Model expectation.
Including our single W boson results obtained at lower \sqrt{s}, the WWgamma
gauge couplings kappa_gamma and lambda_gamma are determined to be kappa_gamma =
0.93 +/- 0.16 +/- 0.09 and lambda_gamma = -0.31 +0.68 -0.19 +/- 0.13
Search for an invisibly decaying Higgs boson in e^+e^- collisions at \sqrt{s} = 183 - 189 GeV
A search for a Higgs boson decaying into invisible particles is performed
using the data collected at LEP by the L3 experiment at centre-of-mass energies
of 183 GeV and 189 GeV. The integrated luminosities are respectively 55.3 pb^-1
and 176.4 pb^-1. The observed candidates are consistent with the expectations
from Standard Model processes. In the hypothesis that the production cross
section of this Higgs boson equals the Standard Model one and the branching
ratio into invisible particles is 100%, a lower mass limit of 89.2 GeV is set
at 95% confidence level
Search for Neutral Higgs Bosons of the Minimal Supersymmetric Standard Model in e+e- Interactions at \sqrt{s} = 189 GeV
A search for the lightest neutral scalar and neutral pseudoscalar Higgs
bosons in the Minimal Supersymmetric Standard Model is performed using 176.4
pb^-1 of integrated luminosity collected by L3 at a center-of-mass energy of
189 GeV. No signal is observed, and the data are consistent with the expected
Standard Model background. Lower limits on the masses of the lightest neutral
scalar and pseudoscalar Higgs bosons are given as a function of tan(beta).
Lower mass limits for tan(beta)>1 are set at the 95% confidence level to be m_h
> 77.1 GeV and m_A > 77.1 GeV
Measurement of Bose-Einstein Correlations in e+e- -> W+W- at root(s)=189GeV
We investigate Bose-Einstein correlations (BEC) in W-pair production at
root(s)=189GeV using the L3 detector at LEP. We observe BEC between particles
from a single W decay in good agreement with those from a light-quark Z decay
sample. We investigate their possible existence between particles coming from
different W's. No evidence for such inter-W BEC is found
Measurement of the Lifetime of the Tau Lepton
The tau lepton lifetime is measured with the L3 detector at LEP using the
complete data taken at centre-of-mass energies around the Z pole resulting in
tau_tau = 293.2 +/- 2.0 (stat) +/- 1.5 (syst) fs. The comparison of this result
with the muon lifetime supports lepton universality of the weak charged current
at the level of six per mille. Assuming lepton universality, the value of the
strong coupling constant, alpha_s is found to be alpha_s(m_tau^2) = 0.319 +/-
0.015(exp.) +/- 0.014 (theory)
Search for Extra Dimensions in Boson and Fermion Pair Production in e+e- Interactions at LEP
Extra spatial dimensions are proposed by recent theories that postulate the
scale of gravity to be of the same order as the electroweak scale. A sizeable
interaction between gravitons and Standard Model particles is then predicted.
Effects of these new interactions in boson and fermion pair production are
searched for in the data sample collected at centre-of-mass energies above the
Z pole by the L3 detector at LEP. In addition, the direct production of a
graviton associated with a Z boson is investigated. No statistically
significant hints for the existence of these effects are found and lower limits
in excess of 1 TeV are derived on the scale of this new theory of gravity
Measurement of the Probability of Gluon Splitting into Charmed Quarks in Hadronic Z Decays
We have measured the probability, n(g->cc~), of a gluon splitting into a
charm-quark pair using 1.7 million hadronic Z decays collected by the L3
detector. Two independent methods have been applied to events with a three-jet
topology. One method relies on tagging charmed hadrons by identifying a lepton
in the lowest energy jet. The other method uses a neural network based on
global event shape parameters. Combining both methods, we measure n(g->cc~)=
[2.45 +/- 0.29 +/- 0.53]%
Measurement of the Photon Structure Function at High Q^2 at LEP
The structure functions of real and virtual photons are derived from cross
section measurements of the reaction e^+e^ -> e^+e^- + hadrons at LEP. The
reaction is studied at \sqrt{s} ~ 91 GeV with the L3 detector. One of the final
state electrons is detected at a large angle relative to the beam direction,
leading to Q^2 values between 40 GeV^2 and 500 GeV^2. The other final state
electron is either undetected or it is detected at a four-momentum transfer
squared P^2 between 1 GeV^2 and 8 GeV^2. These measurements are compared with
predictions of the Quark Parton Model and other QCD based models
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