Ambulatory scintigraphic assessment of transient changes in left ventricular function: a new method for detection of silent myocardial ischaemia

Demonstration of ischaemic left ventricular dysfunction in the absence of chest pain should provide important confirmation of silent myocardial ischaemia in patients with asymptomatic ST segment changes. For this purpose, a new portable scintillation probe (VEST) similar to a miniaturized nuclear stethoscope combined with a Hotter ECG was evaluated. After standard equilibrium radionuclide angiocardiography with technetium-99m labelled red blood cells, the VEST was positioned under gamma-camera control and data were recorded from 1-12 h in 61 unselected patients. Ejection fraction (LVEF), relative changes in volumes, heart rate and ST segment changes were determined. Reproducibility of LVEF at rest (r = 0.91; variability 3.8 ± 3%, N = 19) and during exercise (r = 0.98; variability 3.2 ± 2%, N = 19) was good. In 15 asymptomatic exercise tests four different patterns of LVEF and ST segment responses were identified: (1) decrease in LVEF followed by significant ST depression (five times); (2) ST depression followed by decrease in LVEF (three times); (3) decrease in LVEF without significant ST changes (three times); and (4) ST depression without significant LVEF change (four times). In this still small series, patterns (1) to (3) corresponded to patients with documented coronary artery disease, which was not the case for pattern (4). For detection of silent ischaemia at rest, a decrease in LVEF of >5% lasting for >1 min was defined as ischaemic LV dysfunction. Using this definition, four spontaneous episodes of silent LV dysfunction could be demonstrated in two of three CCU patients with unstable angina during 160-680 min of data recordings without simultaneous ST changes. Based on this initial experience, we conclude that VEST is a reproducible method to detect transient global LV dysfunction and will be useful to confirm silent ischaemia in otherwise uncertain ST segment change

Belastungsabhängige vertikale Doppelbilder und Ptosis

Zusammenfassung: Eine 43-jährige Patientin wurde uns vorgestellt, da seit 2-3Monaten ihr linkes Augenlid in wechselnder Ausprägung hing. Ferner nahm sie auch Doppelbilder in Extrempositionen oder nach schnellen Augenbewegungen wahr und war lichtempfindlich. Die Diagnose ergab ein Keilbeinmeningeom. Es wurde in der Folge 2-mal innerhalb von 3Monaten mittels Radiopeptidtherapie mit 90Y-DOTATOC (Somatostatin-Analogon) behandelt. Bei unserer Patientin führte diese Therapie zu einer Volumenreduktion des Tumors sowie zu einer klinischen Verbesserung und dann Stabilisierun

Faraday waves on a viscoelastic liquid

We investigate Faraday waves on a viscoelastic liquid. Onset measurements and a nonlinear phase diagram for the selected patterns are presented. By virtue of the elasticity of the material a surface resonance synchronous to the external drive competes with the usual subharmonic Faraday instability. Close to the bicriticality the nonlinear wave interaction gives rise to a variety of novel surface states: Localised patches of hexagons, hexagonal superlattices, coexistence of hexagons and lines. Theoretical stability calculations and qualitative resonance arguments support the experimental observations.Comment: 4 pages, 4figure

Targeted alpha-radionuclide therapy of functionally critically located gliomas with 213Bi-DOTA-[Thi8,Met(O2)11]-substance P: a pilot trial

Purpose: Functionally critically located gliomas represent a challenging subgroup of intrinsic brain neoplasms. Standard therapeutic recommendations often cannot be applied, because radical treatment and preservation of neurological function are contrary goals. The successful targeting of gliomas with locally injected beta radiation-emitting 90Y-DOTAGA-substance P has been shown previously. However, in critically located tumours, the mean tissue range of 5mm of 90Y may seriously damage adjacent brain areas. In contrast, the alpha radiation-emitting radionuclide 213Bi with a mean tissue range of 81µm may have a more favourable toxicity profile. Therefore, we evaluated locally injected 213Bi-DOTA-substance P in patients with critically located gliomas as the primary therapeutic modality. Methods: In a pilot study, we included five patients with critically located gliomas (WHO grades II-IV). After diagnosis by biopsy, 213Bi-DOTA-substance P was locally injected, followed by serial SPECT/CT and MR imaging and blood sampling. Besides feasibility and toxicity, the functional outcome was evaluated. Results: Targeted radiopeptide therapy using 213Bi-DOTA-substance P was feasible and tolerated without additional neurological deficit. No local or systemic toxicity was observed. 213Bi-DOTA-substance P showed high retention at the target site. MR imaging was suggestive of radiation-induced necrosis and demarcation of the tumours, which was validated by subsequent resection. Conclusion: This study provides proof of concept that targeted local radiotherapy using 213Bi-DOTA-substance P is feasible and may represent an innovative and effective treatment for critically located gliomas. Primarily non-operable gliomas may become resectable with this treatment, thereby possibly improving the prognosi

From ferromagnetism to spin-density wave: Magnetism in the two channel periodic Anderson model

The magnetic properties of the two-channel periodic Anderson model for uranium ions, comprised of a quadrupolar and a magnetic doublet are investigated through the crossover from the mixed-valent to the stable moment regime using dynamical mean field theory. In the mixed-valent regime ferromagnetism is found for low carrier concentration on a hyper-cubic lattice. The Kondo regime is governed by band magnetism with small effective moments and an ordering vector \q close to the perfect nesting vector. In the stable moment regime nearest neighbour anti-ferromagnetism dominates for less than half band filling and a spin density wave transition for larger than half filling. $T_m$ is governed by the renormalized RKKY energy scale \mu_{eff}^2 ^2 J^2\rho_0(\mu).Comment: 4 pages, RevTeX, 3 eps figure

Influence of through-flow on linear pattern formation properties in binary mixture convection

We investigate how a horizontal plane Poiseuille shear flow changes linear convection properties in binary fluid layers heated from below. The full linear field equations are solved with a shooting method for realistic top and bottom boundary conditions. Through-flow induced changes of the bifurcation thresholds (stability boundaries) for different types of convective solutions are deter- mined in the control parameter space spanned by Rayleigh number, Soret coupling (positive as well as negative), and through-flow Reynolds number. We elucidate the through-flow induced lifting of the Hopf symmetry degeneracy of left and right traveling waves in mixtures with negative Soret coupling. Finally we determine with a saddle point analysis of the complex dispersion relation of the field equations over the complex wave number plane the borders between absolute and convective instabilities for different types of perturbations in comparison with the appropriate Ginzburg-Landau amplitude equation approximation. PACS:47.20.-k,47.20.Bp, 47.15.-x,47.54.+rComment: 19 pages, 15 Postscript figure

Shear induced instabilities in layered liquids

Motivated by the experimentally observed shear-induced destabilization and reorientation of smectic A like systems, we consider an extended formulation of smectic A hydrodynamics. We include both, the smectic layering (via the layer displacement u and the layer normal p) and the director n of the underlying nematic order in our macroscopic hydrodynamic description and allow both directions to differ in non equilibrium situations. In an homeotropically aligned sample the nematic director does couple to an applied simple shear, whereas the smectic layering stays unchanged. This difference leads to a finite (but usually small) angle between n and p, which we find to be equivalent to an effective dilatation of the layers. This effective dilatation leads, above a certain threshold, to an undulation instability of the layers. We generalize our earlier approach [Rheol. Acta, vol.39(3), 15] and include the cross couplings with the velocity field and the order parameters for orientational and positional order and show how the order parameters interact with the undulation instability. We explore the influence of various material parameters on the instability. Comparing our results to recent experiments and molecular dynamic simulations, we find a good qualitative agreement.Comment: 15 pages, 12 figures, accepted for publication in PR

Fundamental scaling laws of on-off intermittency in a stochastically driven dissipative pattern forming system

Noise driven electroconvection in sandwich cells of nematic liquid crystals exhibits on-off intermittent behaviour at the onset of the instability. We study laser scattering of convection rolls to characterize the wavelengths and the trajectories of the stochastic amplitudes of the intermittent structures. The pattern wavelengths and the statistics of these trajectories are in quantitative agreement with simulations of the linearized electrohydrodynamic equations. The fundamental $\tau^{-3/2}$ distribution law for the durations $\tau$ of laminar phases as well as the power law of the amplitude distribution of intermittent bursts are confirmed in the experiments. Power spectral densities of the experimental and numerically simulated trajectories are discussed.Comment: 20 pages and 17 figure