46 research outputs found
Cure of Helicobacter pylori infection in patients with reflux oesophagitis treated with long term omeprazole reverses gastritis without exacerbation of reflux disease: results of a randomised controlled trial
BACKGROUND: Helicobacter pylori gastritis may progress to glandular
atrophy and intestinal metaplasia, conditions that predispose to gastric
cancer. Profound suppression of gastric acid is associated with increased
severity of H pylori gastritis. This prospective randomised study aimed to
investigate whether H pylori eradication can influence gastritis and its
sequelae during long term omeprazole therapy for gastro-oesophageal reflux
disease (GORD). METHODS: A total of 231 H pylori positive GORD patients
who had been treated for > or =12 months with omeprazole maintenance
therapy (OM) were randomised to either continuation of OM (OM only; n =
120) or OM plus a one week course of omeprazole, amoxycillin, and
clarithromycin (OM triple; n = 111). Endoscopy with standardised biopsy
sampling as well as symptom evaluation were performed at baseline and
after one and two years. Gastritis was assessed according to the Sydney
classification system for activity, inflammation, atrophy, intestinal
metaplasia, and H pylori density. RESULTS: Corpus gastritis activity at
entry was moderate or severe in 50% and 55% of the OM only and OM triple
groups, respectively. In the OM triple group, H pylori was eradicated in
90 (88%) patients, and activity and inflammation decreased substantially
in both the antrum and corpus (p<0.001, baseline v two years). Atrophic
gastritis also improved in the corpus (p<0.001) but not in the antrum. In
the 83 OM only patients with continuing infection, there was no change in
antral and corpus gastritis activity or atrophy, but inflammation
increased (p<0.01). H pylori eradication did not alter the dose of
omeprazole required, or reflux symptoms. CONCLUSIONS: Most H pylori
positive GORD patients have a corpus predominant pangastritis during
omeprazole maintenance therapy. Eradication of H pylori eliminates gastric
mucosal inflammation and induces regression of corpus glandular atrophy. H
pylori eradication did not worsen reflux disease or lead to a need for
increased omeprazole maintenance dose. We therefore recommend eradication
of H pylori in GORD patients receiving long term acid suppression
Geometry and field theory in multi-fractional spacetime
We construct a theory of fields living on continuous geometries with
fractional Hausdorff and spectral dimensions, focussing on a flat background
analogous to Minkowski spacetime. After reviewing the properties of fractional
spaces with fixed dimension, presented in a companion paper, we generalize to a
multi-fractional scenario inspired by multi-fractal geometry, where the
dimension changes with the scale. This is related to the renormalization group
properties of fractional field theories, illustrated by the example of a scalar
field. Depending on the symmetries of the Lagrangian, one can define two
models. In one of them, the effective dimension flows from 2 in the ultraviolet
(UV) and geometry constrains the infrared limit to be four-dimensional. At the
UV critical value, the model is rendered power-counting renormalizable.
However, this is not the most fundamental regime. Compelling arguments of
fractal geometry require an extension of the fractional action measure to
complex order. In doing so, we obtain a hierarchy of scales characterizing
different geometric regimes. At very small scales, discrete symmetries emerge
and the notion of a continuous spacetime begins to blur, until one reaches a
fundamental scale and an ultra-microscopic fractal structure. This fine
hierarchy of geometries has implications for non-commutative theories and
discrete quantum gravity. In the latter case, the present model can be viewed
as a top-down realization of a quantum-discrete to classical-continuum
transition.Comment: 1+82 pages, 1 figure, 2 tables. v2-3: discussions clarified and
improved (especially section 4.5), typos corrected, references added; v4:
further typos correcte