2,077 research outputs found

    Bariatric surgery in an obese patient with Albright hereditary osteodystrophy: a case report

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    INTRODUCTION: We report for the first time the case of a patient with Albright hereditary osteodystrophy and pseudopseudohypoparathyroidism who underwent a Roux-en-Y gastric bypass. CASE PRESENTATION: A 26-year-old obese Caucasian woman with Albright hereditary osteodystrophy with pseudopseudohypoparathyroidism (heterozygous mutation (L272F) in GNAS1 exon 10 on molecular analysis) was treated with gastric bypass. She had the classical features of Albright hereditary osteodystrophy: short stature (138cm), obesity (body mass index 49.5kg/m2), bilateral shortening of the fourth and fifth metacarpals, short neck, round and wide face with bombed front and small eyes. Before the gastric bypass was performed, biochemical determination revealed a slightly low serum calcium level (2.09mmol/L; normal range 2.1 to 2.5mmol/l), and an elevated parathyroid hormone level (87ng/L; normal range 10 to 70ng/L) associated with low vitamin D level (19μg/L; normal range 30 to 50μg/L). Vitamin D supplementation was prescribed before surgery. After the Roux-en-Y gastric bypass, she achieved a progressive substantial weight loss, from 94kg (body mass index 49.5kg/m2) to 49kg (body mass index 25.9kg/m2) in one year. Her weight then stabilized at 50kg (body mass index 26kg/m2) during our three years of follow-up. Before the operation and every three months after it, she was screened for nutritional deficiencies, and serum markers of bone turnover and renal function were monitored. Considering the deficiencies in zinc, magnesium, calcium, vitamin D and vitamin B12, appropriate supplementation was prescribed. Before and two years after the Roux-en-Y gastric bypass, a dual-energy X-ray absorptiometry assessment of bone density was performed that showed no changes on her lumbar column (0.882g/cm2 and both T-score and Z-score of -1.5 standard deviation). In addition, bone microarchitecture with a measurement of her trabecular bone score was found to be normal. CONCLUSION: This is the first case of Roux-en-Y gastric bypass described in a patient with pseudopseudohypoparathyroidism showing that such a procedure seems to be safe in obese patients with Albright hereditary osteodystrophy and pseudopseudohypoparathyroidism if appropriately followed up. As obesity is a prominent feature of Albright hereditary osteodystrophy, such patients might seek bariatric surgery. After a Roux-en-Y gastric bypass, patients with Albright hereditary osteodystrophy associated with pseudopseudohypoparathyroidism need long-term follow-up on nutritional and metabolic issues

    Measurement of the Cotton Mouton effect of water vapour

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    In this paper we report on a measurement of the Cotton Mouton effect of water vapour. Measurement performed at room temperature (T=301T=301 K) with a wavelength of 1064 nm gave the value Δnu=(6.67±0.45)1015\Delta n_u = (6.67 \pm 0.45) \cdot 10^{-15} for the unit magnetic birefringence (1 T magnetic field and atmospheric pressure)

    New PVLAS model independent limit for the axion coupling to γγ\gamma\gamma for axion masses above 1meV

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    During 2014 the PVLAS experiment has started data taking with a new apparatus installed at the INFN Section of Ferrara, Italy. The main target of the experiment is the observation of magnetic birefringence of vacuum. According to QED, the ellipticity generated by the magnetic birefringence of vacuum in the experimental apparatus is expected to be ψ(QED)5×1011\psi^{\rm(QED)} \approx 5\times10^{-11}. No ellipticity signal is present so far with a noise floor ψ(noise)2.5×109\psi^{\rm(noise)} \approx 2.5\times10^{-9} after 210 hours of data taking. The resulting ellipticity limit provides the best model independent upper limit on the coupling of axions to γγ\gamma\gamma for axion masses above 10310^{-3}eV

    Measurements of vacuum magnetic birefringence using permanent dipole magnets: the PVLAS experiment

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    The PVLAS collaboration is presently assembling a new apparatus (at the INFN section of Ferrara, Italy) to detect vacuum magnetic birefringence (VMB). VMB is related to the structure of the QED vacuum and is predicted by the Euler-Heisenberg-Weisskopf effective Lagrangian. It can be detected by measuring the ellipticity acquired by a linearly polarised light beam propagating through a strong magnetic field. Using the very same optical technique it is also possible to search for hypothetical low-mass particles interacting with two photons, such as axion-like (ALP) or millicharged particles (MCP). Here we report results of a scaled-down test setup and describe the new PVLAS apparatus. This latter one is in construction and is based on a high-sensitivity ellipsometer with a high-finesse Fabry-Perot cavity (>4×105>4\times 10^5) and two 0.8 m long 2.5 T rotating permanent dipole magnets. Measurements with the test setup have improved by a factor 2 the previous upper bound on the parameter AeA_e, which determines the strength of the nonlinear terms in the QED Lagrangian: Ae(PVLAS)<3.3×1021A_e^{\rm (PVLAS)} < 3.3 \times 10^{-21} T2^{-2} 95% c.l. Furthermore, new laboratory limits have been put on the inverse coupling constant of ALPs to two photons and confirmation of previous limits on the fractional charge of millicharged particles is given

    First results from the new PVLAS apparatus: a new limit on vacuum magnetic birefringence

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    Several groups are carrying out experiments to observe and measure vacuum magnetic birefringence, predicted by Quantum Electrodynamics (QED). We have started running the new PVLAS apparatus installed in Ferrara, Italy, and have measured a noise floor value for the unitary field magnetic birefringence of vacuum Δnu(vac)=(4±20)×1023\Delta n_u^{\rm (vac)}= (4\pm 20) \times 10^{-23} T2^{-2} (the error represents a 1σ\sigma deviation). This measurement is compatible with zero and hence represents a new limit on vacuum magnetic birefringence deriving from non linear electrodynamics. This result reduces to a factor 50 the gap to be overcome to measure for the first time the value of Δnu(vac,QED)\Delta n_u^{\rm (vac,QED)} predicted by QED: Δnu(vac,QED)=4×1024\Delta n_u^{\rm (vac,QED)}= 4\times 10^{-24} ~T2^{-2}. These birefringence measurements also yield improved model-independent bounds on the coupling constant of axion-like particles to two photons, for masses greater than 1 meV, along with a factor two improvement of the fractional charge limit on millicharged particles (fermions and scalars), including neutrinos

    Impaired GH Secretion in Patients with SHOX Deficiency and Efficacy of Recombinant Human GH Therapy.

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    Background/Aims: Mutations of the short stature homeobox-containing (SHOX) gene on the pseudoautosomal region of the sex chromosomes cause short stature. GH treatment has been recently proposed to improve height in short patients with SHOX deficiency. The aim of this study was to evaluate GH secretion and analyze growth and safety of recombinant human GH (rhGH) therapy in short children and adolescents with SHOX deficiency. Patients and Design: We studied 16 patients (10 females; 9.7 ± 2.9 years old; height -2.46 ± 0.82 standard deviation score, SDS) with SHOX deficiency. All subjects underwent auxological evaluations, biochemical investigations, and were treated with rhGH (0.273 ± 0.053 mg/kg/week). Results: Impaired GH secretion was present in 37.5% of the studied subjects. Comparing baseline data with those at the last visit, we found that rhGH treatment improved growth velocity SDS (from -1.03 ± 1.44 to 2.77 ± 1.95; p = 0.001), height SDS (from -2.41 ± 0.71 to -1.81 ± 0.87; p < 0.001), and IGF-1 values (from -0.57 ± 1.23 to 0.63 ± 1.63 SDS, p = 0.010) without affecting body mass index SDS. Height SDS measured at the last visit was significantly correlated with chronological age (r = -0.618, p = 0.032), bone age (r = -0.582, p = 0.047) and height SDS (r = 0.938, p < 0.001) at the beginning of treatment. No adverse events were reported on rhGH therapy which was never discontinued. Conclusion: These data showed that impaired GH secretion is not uncommon in SHOX deficiency subjects, and that rhGH therapy may be effective in increasing height in most of these patients independent of their GH secretory status, without causing any adverse events of concern

    Probing the dynamics of quasicrystal growth using synchrotron live imaging

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    The dynamics of quasicrystal growth remains an unsolved problem in condensed matter. By means of synchrotron live imaging, facetted growth proceeding by the tangential motion of ledges at the solid-melt interface is clearly evidenced all along the solidification of icosahedral AlPdMn quasicrystals. The effect of interface kinetics is significant so that nucleation and free growth of new facetted grains occur in the melt when the solidification rate is increased. The evolution of these grains is explained in details, which reveals the crucial role of aluminum rejection, both in the poisoning of grain growth and driving fluid flow

    Metric gravity theories and cosmology:II. Stability of a ground state in f(R) theories

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    A fundamental criterion of viability of any gravity theory is existence of a stable ground-state solution being either Minkowski, dS or AdS space. Stability of the ground state is independent of which frame is physical. In general, a given theory has multiple ground states and splits into independent physical sectors. All metric gravity theories with the Lagrangian being a function of Ricci tensor are dynamically equivalent to Einstein gravity with a source and this allows us to study the stability problem using methods developed in GR. We apply these methods to f(R) theories. As is shown in 13 cases of Lagrangians the stability criterion works simply and effectively whenever the curvature of the ground state is determined. An infinite number of gravity theories have a stable ground state and further viability criteria are necessary.Comment: A modified and expanded version of a second part of the paper which previously appeared as gr-qc/0702097v1. The first, modified part is now published as gr-qc/0702097v2 and as a separate paper in Class. Qu. Grav. The present paper matches the published versio
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