MRI findings in nonalcoholic steatohepatitis: correlation with histopathology and clinical staging

Purpose

To evaluate magnetic resonance imaging (MRI) findings of nonalcoholic steatohepatitis (NASH) and to determine the correlation of MRI findings with histopathology and Mayo End-Stage Liver Disease (MELD) score.

Materials and Methods

Thirty patients (18 males, 12 females; mean age: 57±8.9 years; age range: 35–71 years) with histopathologically proven NASH who underwent MRI examinations between January 2001 and October 2005 were included in the study. Two radiologists retrospectively reviewed all magnetic resonance (MR) examinations in consensus to evaluate the presence and extent of predetermined findings of NASH including liver steatosis, early patchy liver enhancement indicating inflammation and liver fibrosis. The findings detected on MRI were correlated and compared to histopathological findings and MELD score by using nonparametric Spearman correlation coefficient and Kruskal–Wallis analysis of variance.

Results

Liver steatosis was observed in 10 of 30 patients; early patchy liver enhancement, in 8 of 30 patients and liver fibrosis in 19 of 30 patients on MR images. Liver fibrosis was reticular in all these patients. There were statistically significant moderate correlations between MRI findings of liver steatosis and histopathologic grades of steatosis (r=0.43; P<.05), and between MRI findings of fibrosis and histopathologic stages of fibrosis (r=0.61; P<.001). Early patchy enhancement did not demonstrate statistically significant correlation with inflammation (P=.28). There was no statistically significant overall correlation between MRI findings of NASH and MELD score.

Conclusion

MRI findings of liver steatosis and fibrosis in NASH showed moderate correlations with histopathologic grades of steatosis and stages of fibrosis, but MRI findings of NASH did not demonstrate any significant correlations with MELD score.     

Feasibility of post-gadolinium three-dimensional gradient-echo sequence to evaluate the pulmonary arterial vasculature

Purpose

To determine the feasibility of post-gadolinium three-dimensional gradient-echo (3D-GE) sequence for the evaluation of the pulmonary arterial vasculature in patients with suspected pulmonary embolism (PE) and in patients with a variety of other disease processes.

Materials and Methods

Twenty-six consecutive patients (18 females, 8 males; mean age±S.D., 46.6±21.1 years) who underwent chest magnetic resonance imaging (MRI) including post-gadolinium 3D-GE sequence for the evaluation of PE (Group A, n=13) and a variety of other disease processes (Group B, n=13) were included in the study. Post-gadolinium 3D-GE MR sequences were retrospectively, independently and blindly evaluated by two reviewers for the image quality of pulmonary arterial vasculature, and findings of PE and other disease processes. Clinical and imaging follow-up data for all patients were obtained. Interobserver agreement was calculated by kappa statistics.

Results

All central and lobar pulmonary arteries, 71.4–89.6% of segmental arteries and 46.7–52.7% of subsegmental arterial units in both groups were visualized with sufficient diagnostic image quality on post-gadolinium 3D-GE sequences. PE involving lobar and segmental arteries was diagnosed in two patients in each group. Other disease processes including pneumonia, lung nodules, superior vena cava stenosis, lung metastases, chronic lymphocytic leukemia and aortic aneurysm were detected in 10 of 26 patients. There was good to excellent interobserver agreement (0.73 to 1.00) for all findings.

Conclusion

Post-gadolinium 3D-GE sequence may be an alternative technique for the visualization of central, lobar and segmental arteries, and may diagnose PE and other pathologies involving the chest in different patient populations.     

Dynamics of peptidergic secretory granule transport are regulated by neuronal stimulation

Background  

Peptidergic neurons store and secrete the contents of large dense core vesicles (LDCVs) from axon terminals and from dendrites. Secretion of peptides requires a highly regulated exocytotic mechanism, plus coordinated synthesis and transport of LDCVs to their sites of release. Although these trafficking events are critical to function, little is known regarding the dynamic behavior of LDCVs and the mechanisms by which their transport is regulated. Sensory neurons also package opiate receptors in peptide-containing LDCVs, which is thought to be important in pain sensation. Since peptide granules cannot be refilled locally after their contents are secreted, it is particularly important to understand how neurons support regulated release of peptides.     

Ternary generalization of Pauli’s principle and the <Emphasis Type="Italic">Z</Emphasis><Subscript>6</Subscript>-graded algebras

We show how the discrete symmetries Z ₂ and Z ₃ combined with the superposition principle result in the SL(2,C) symmetry of quantum states. The role of Pauli’s exclusion principle in the derivation of the SL(2,C) symmetry is put forward as the source of the macroscopically observed Lorentz symmetry; then it is generalized for the case of the Z ₃ grading replacing the usual Z ₂ grading, leading to ternary commutation relations. We discuss the cubic and ternary generalizations of Grassmann algebra. Invariant cubic forms on such algebras are introduced, and it is shown how the SL(2,C) group arises naturally in the case of two generators only, as the symmetry group preserving these forms. The wave equation generalizing the Dirac operator to the Z ₃-graded case is introduced, whose diagonalization leads to a sixthorder equation. The solutions of this equation cannot propagate because their exponents always contain non-oscillating real damping factor. We show how certain cubic products can propagate nevertheless. The model suggests the origin of the color SU(3) symmetry.     

Self-assembled alkanethiol structures on gold: A further insight into the origins of structural rearrangement phenomena

Self-assembled structures of alkanethiols that have been deposited on gold from ethanolic solutions are susceptible to both chemical and physical changes: ethanol provides a medium for the formation of S-alkyl hydrogen thiocarbonates and related compounds via reaction with dissolved, atmospheric, CO₂. Deposition from ethanolic solutions results in multilayered structures incorporating these compounds, which at room temperature are susceptible to time-dependent structural rearrangement and molecular migration.     

Brillouin and ultrasonic study of the temperature dependence of the elastic constants in NaCN

The temperature dependence of the elastic constants of NaCN has been studied by propagation of ultrasonic waves at 15 MHz and by Brillouin scattering at 3 GHz over the temperature range from 287K to 355K. c₄₄ is observed to soften linearly with temperature as the order-disorder phase transition at 284K is approached from above. The other elastic constants also soften, except for c₁₂ which stiffens. Considerable dispersion is seen in the values of c₄₄ obtained ultrasonically and by Brillouin scattering. Measurements of the temperature dependence of the density are also reported.     

Electron spectroscopy applied to the study of reactivity at metal surfaces — A review

Photoelectron spectroscopy (PES) has become an important tool in the study of surfaces and the solid state. This review discusses information obtained on the interaction of gases with metal surfaces. The fundamentals of electron spectroscopy are briefly reviewed and experimental methods outlined. Approaches to the interpretation of both X-ray photoelectron spectroscopy (XPS) and ultra-violet photoelectron spectra (UPS) are discussed. The chemisorption of carbon monoxide is examined in detail, PES distinguishes two situations, where CO retains its molecular identity and where dissociation occurs. Bonding of the molecule is considered, as are factors affecting dissociation. Some XPS investigations of metal oxidation are examined and the significance of the several oxygen 1s peaks observed is discussed. The adsorption and decomposition of organic molecules has been studied primarily by UPS. Several investigations are summarized, and the decomposition of formic acid considered in detail. The application of electron excited Auger electron spectroscopy is briefly discussed.     

Ab initio calculation of the spin-rotation constant for 2Π diatomics: Test of the Van Vleck approximation

Ab initio calculations are carried out to determine γ^Π (true), the first-order contribution to the spin-rotation constant, γ^Π, for the X²Π ground states of OH, HF⁺, and HCl⁺ and their deuterated analogs. These calculations demonstrate that the contribution of this term to the experimentally determined value of γ^Π is small, as has been previously conjectured. Furthermore, it is found in the cases under study that the Van Vleck approximation to γ^Π (true) significantly overestimates its importance, and a more realistic approximation is presented.     

Determination of the solubility of organic compounds. II

Summary In general, solid particles liquify when they are exposed to air laden with the vapor of a liquid in which they are soluble. There are exceptions, however, which may be explained by assuming the formation of a solvate.

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Zusammenfassung Feste Teilchen verflüssigen sich im allgemeinen, wenn sie Luft ausgesetzt sind, die mit dem Dampf einer Flüssigkeit geladen ist, in der sie löslich sind. Es wurden aber Ausnahmen gefunden, die möglicherweise durch die Bildung von Solvaten erklärt werden können.

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Résumé Généralement, les particules solides se liquéfient si elles sont exposées à l'air chargé de la vapeur d'un liquide dans lequel elles sont solubles. Il existe cependant des exceptions que l'on peut expliquer en supposant la formation de solvates.

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On the occasion of the hundredth return ofFriedrich Emich's birthday.

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The authors wish to express their appreciation to ProfessorO. F. Steinbach for his suggestions and advice.     

Über den Einfluß von einwertigen Zwischenschichtkationen auf die elektrische Leitfähigkeit von Vermikulilten in verschiedenen Hydrationszuständen (Dielektrische Messungen an Schichtsilicaten IV (1, 2, 3))

Zusammenfassung An Vermikulitkristallen mit Li⁺ und Na⁺ als Zwischenschichtkationen in verschiedenen Hydrations-zuständen (trocken, isolierte Wassermoleküle und monomolekulare Wasserschichten) wurde der Realteil der dielektrischen Permeabilitätg und der dielektrische Verlustfaktortg im Frequenzbereich zwischen 30 Hz und 10 MHz gemessen. Die elektrische Leitfähigkeit in Richtung der Schichtnormalen wird sowohl vom Hydratwasser als auch (insbesondere bei niedriger Schichtladung) von der Natur der einwertigen Zwischenschichtkationen bestimmt: Bei niederen Frequenzen und niederen Hydrationszuständen dominieren Relaxationsphänomene auf Grund der Beweglichkeit dieser Kationen. Hingegen resultiert die Leitfähigkeit in den Stufen mit isolierten Wassermolekülen und mit monomolekularen H₂O-Schichten weitgehend aus einem Wanderungsmechanismus vonL-Defekten innerhalb der Wasserstrukturen, wie er bei Vermikuliten mit zweiwertigen Kationen nachgewiesen wurde.

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Summary The dielectric permeability s' and the dielectric losstg of vermiculite crystals with Li⁺ and Na⁺ as interlayer cations in different states of hydration (completely dehydrated, with isolated water molecules and with monomolecular water layers) were measured in the frequency range between 30 Hz and 10 MHz. The electrical conductivity normal to the silicate layers was determined by the influence of the hydrate water as well as especially in the case o£ low layer charge by the nature of the monovalent interlayer cations. At low frequencies and low states of hydration it could be interpreted by a relaxation process of the interlayer cations. With isolated water molecules and with monomolecular water layers the conductivity at higher frequencies was mainly determined by a mechanism of diffusion of structuralL-defects within the water layers as in the case of hydrated vermiculites with divalent cations.

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Mit 9 Abbildungen und 2 Tabellen