Ataxia and the Role of Antigliadin Antibodies

Background:

Although it is acknowledged that patients with celiac disease can develop neurological complications such as ataxia, the association of antigliadin antibodies in the etiology of sporadic ataxia and the usefulness of this testing in diagnosis of ataxia is controversial.

Methods:

We investigated this association by testing for the presence of IgG and IgA antigliadin antibodies in 56 ataxic patients and 59 controls. The ataxia patients were subsequently classified into three groups: sporadic, hereditary and MSA.

Results:

Of the total ataxic patients, 6/56 (11%) were positive for either IgG or IGA antigliadin antibodies compared to the controls of which 5/59 (8%) were positive (p = 0.68). In a subgroup analysis, 4/29 (14%) of the samples in the sporadic ataxic subgroup were positive for antigliadin antibodies (IgG or IgA) compared to control (p = 0.44). Similar negative results were found in the remaining subgroup analyses.

Conclusions:

These results do not support an association between antigliadin antibodies and sporadic ataxias.

Comparison between transthoracic and transesophageal echocardiography in screening for infective endocarditis in patients with Staphylococcus aureus bacteremia

Echocardiography is an important diagnostic tool in evaluating a patient with Staphylococcus aureus bacteremia (SAB) for diagnosing infective endocarditis (IE). We sought to compare the utility of transthoracic echocardiography (TTE) with transesophageal echocardiography (TEE) in screening for IE in patients with SAB. We performed a retrospective chart review of 285 adult patients from two tertiary care hospitals with at least one positive blood culture for S. aureus between 2010 and 2012. Patients who underwent echocardiography were divided into two groups: TTE (screened with TTE only) and TEE (screened with both TTE and TEE). The demographic factors and clinical outcomes were compared between the groups. Of the 285 charts reviewed, 213 (74.7 %) patients were screened with echocardiography: 183 (85.9 %) were screened with TTE alone and 30 (14.1 %) were screened with both TTE and TEE. TEE disclosed more cases of definite IE than TTE (8 [26.7 %] vs. 22 [12.0 %], p = 0.046). The TEE group had higher mortality than the TTE group (15 [50.0 %] vs. 43 [23.5 %], p = 0.004). In patients with definite IE, mortality was higher in the TEE group than in the TTE group (6 [75.0 %] vs. 6 [27.3 %], p = 0.034). TEE discovered additional findings that were missed by TTE in 36.7 % of cases and refuted the findings of TTE in 13.3 % of cases. We do not support the routine use of TEE in patients with uncomplicated SAB. High-risk patients in which IE is a serious consideration should undergo investigation with TEE.

On the roles of graphene oxide doping for enhanced supercurrent in MgB2 based superconductors

Due to their graphene-like properties after oxygen reduction, incorporation of graphene oxide (GO) sheets into correlated-electron materials offers a new pathway for tailoring their properties. Fabricating GO nanocomposites with polycrystalline MgB2 superconductors leads to an order of magnitude enhancement of the supercurrent at 5 K/8 T and 20 K/4 T. Herein, we introduce a novel experimental approach to overcome the formidable challenge of performing quantitative microscopy and microanalysis of such composites, so as to unveil how GO doping influences the structure and hence the material properties. Atom probe microscopy and electron microscopy were used to directly image the GO within the MgB2, and we combined these data with computational simulations to derive the property-enhancing mechanisms. Our results reveal synergetic effects of GO, namely, via localized atomic (carbon and oxygen) doping as well as texturing of the crystals, which provide both inter- and intra-granular flux pinning. This study opens up new insights into how low-dimensional nanostructures can be integrated into composites to modify the overall properties, using a methodology amenable to a wide range of applications.

Excitation Energy Transfer among Chlorophyll a Molecules in Polystyrene: Concentration Dependence of Quantum Yield, Polarization and Lifetime of Fluorescence

Electronic excitation energy transfer was studied for chlorophyll a in a solid solution of poly­styrene by measuring the concentration quenching of quantum yield, polarization, and lifetime of fluorescence. The concentration quenching of the experimental fluorescence quantum yield is adequately described by Kelly and Porter’s empirical formula (Proc. Roy. Soc., Lond. A 315, 149, 1970), and of polarization of fluorescence by the Jablonski theory (Acta Phys. Pol., 14, 295, 1955). With increasing concentration of chlorophyll a, the fluorescence peak at 672 nm (mainly monomer) is red-shifted, the intensity of the emission peak at ∼730 nm (mainly aggregate) relative to that at the shorter wavelength is increased. The R̅0 values, calculated by using total concentrations, for the emission at 672 nm and 730 nm are 73 ± 2 Å and 45 ±1 Å, respectively. This may suggest that the chlorophyll monomers have a greater efficiency of energy transfer than the aggregates, which fluoresce at ∼ 730 nm.

Antenatal steroid exposure and outcomes of very premature infants: a regional cohort study

OBJECTIVE

To compare mortality, short-term morbidity and long-term neurodevelopmental outcomes of <29 week premature infants with antenatal steroid exposure (none, incomplete and complete).

PATIENTS AND METHODS

Multicentre retrospective cohort study, within a geographically defined area in Australia served by a network of 10 neonatal intensive care units (NICUs), of infants <29 weeks gestational age, admitted to NICUs between 1998 and 2004. Outcome measures included hospital survival, perinatal complications and functional disability at 2-3 years follow-up.

RESULTS

2549 neonates were included; 319 (12.5%) received no exposure to steroids. Hospital mortality (OR 0.59, 95% CI 0.45 to 0.76, p<0.001, intraventricular haemorrhage (IVH) (OR 0.58, 95% CI 0.42 to 0.81, p=0.001) and necrotising entercolitis (NEC) (OR 0.62, 95% CI 0.42 to 0.91, p=0.018) was less likely in infants with any steroid exposure. Any steroid exposure was associated with less need for surfactant (OR 0.41, 95% CI 0.30 to 0.57, p<0.001) and mechanical ventilation (OR 0.30, 95% CI 0.17 to 0.52, p<0.001). Subgroup analyses demonstrated differences in outcomes only with complete steroid coverage and not with incomplete coverage. Survival benefit and reduction in the incidence of severe IVH was evident from 24 to 28 weeks. Long-term neurodevelopmental data available for 1473 survivors showed no significant difference in outcomes with steroid exposure after multivariate analysis.

CONCLUSIONS

Exposure to a complete course of antenatal steroids is associated with higher infant survival rates, lower rates of severe IVH and NEC compared to an incomplete course or no exposure. Any exposure to steroids reduces the risk of moderate cerebral palsy, however, long-term neurodevelopmental outcome may not be affected by steroid exposure.

Malignant combined squamomelanocytic tumor: a clinical case

A combined squamomelanocytic tumor is an exceedingly rare occurrence; little is known about its pathogenesis. A definitive diagnosis can only be made via histological examination. We describe herein an 83 year-old man who was discovered to have this combined tumor and recommend the appropriate management for such a lesion.

Surface-enhanced charge-density-wave instability in underdoped Bi2Sr(2-x)La(x)CuO(6+δ)

Neutron and X-ray scattering experiments have provided mounting evidence for spin and charge ordering phenomena in underdoped cuprates. These range from early work on stripe correlations in Nd-LSCO to the latest discovery of charge-density-waves in YBa2Cu3O(6+x). Both phenomena are characterized by a pronounced dependence on doping, temperature and an externally applied magnetic field. Here, we show that these electron-lattice instabilities exhibit also a previously unrecognized bulk-surface dichotomy. Surface-sensitive electronic and structural probes uncover a temperature-dependent evolution of the CuO2 plane band dispersion and apparent Fermi pockets in underdoped Bi2 Sr(2-x) La(x) CuO(6+δ) (Bi2201), which is directly associated with an hitherto-undetected strong temperature dependence of the incommensurate superstructure periodicity below 130 K. In stark contrast, the structural modulation revealed by bulk-sensitive probes is temperature-independent. These findings point to a surface-enhanced incipient charge-density-wave instability, driven by Fermi surface nesting. This discovery is of critical importance in the interpretation of single-particle spectroscopy data, and establishes the surface of cuprates and other complex oxides as a rich playground for the study of electronically soft phases.