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.     

The effect of metal dispersion on the resonance of antennas at infrared frequencies

In this paper the optical parameters at infrared frequencies of metallic thin films were obtained experimentally using a variable angle spectroscopic ellipsometer and used to simulate numerically the frequency response of antennas and antenna-coupled detectors at infrared frequencies (5–15 μm). The simulation results agree with previously published data and practical guidelines are presented for the design and fabrication of dipole and bowtie antennas at infrared frequencies.     

Identification of potential trypanothione reductase inhibitors among commercially available $$\upbeta $$-carboline derivatives using chemical space,lead-like and drug-like filters,pharmacophore models and molecular docking

American trypanosomiasis or Chagas disease caused by the protozoan Trypanosoma cruzi (T. cruzi) is an important endemic trypanosomiasis in Central and South America. This disease was considered to be a priority in the global plan to combat neglected tropical diseases, 2008–2015, which indicates that there is an urgent need to develop more effective drugs. The development of new chemotherapeutic agents against Chagas disease can be related to an important biochemical feature of T. cruzi: its redox defense system. This system is based on trypanothione (\(N^{1}\),\(N^{8}\)-bis(glutathyonil)spermidine) and trypanothione reductase (TR), which are rather unique to trypanosomes and completely absent in mammalian cells. In this regard, tricyclic compounds have been studied extensively due to their ability to inhibit the T. cruzi TR. However, synthetic derivatives of natural products, such as \(\upbeta \)-carboline derivatives (\(\upbeta \)-CDs), as potential TR inhibitors, has received little attention. This study presents an analysis of the structural and physicochemical properties of commercially available \(\upbeta \)-CDs in relation to compounds tested against T. cruzi in previously reported enzymatic assays and shows that \(\upbeta \)-CDs cover chemical space that has not been considered for the design of TR inhibitors. Moreover, this study presents a ligand-based approach to discover potential TR inhibitors among commercially available \(\upbeta \)-CDs, which could lead to the generation of promising \(\upbeta \)-CD candidates.     

Carbon and oxygen isotope working standards from C3 and C4 photosynthates

A preparation of organic working standards for the online measurement of ¹³C/¹²C and ¹⁸O/¹⁶O ratios in biological material is presented. The organic working standards are simple and inexpensive C₃ and C₄ carbohydrates (sugars or cellulose) from distinct geographic origin, including white sugar, toilet and XEROX papers from Switzerland, maize from Ivory Coast, cane sugar from Brazil, papyrus from Egypt, and the core of the stem of a Cyperus papyrus plant from Kenya. These photosynthetic products were compared with International Atomic Energy standards CH-3 and CH-6 and other calibration materials. The presented working standards cover a 15 ‰ range of ¹³C/¹²C ratios and 9 ‰ for ¹⁸O/¹⁶O, with a precision<±0.2 ‰ for n>10.     

A Spin Label Study of the Effects of NO2, SO2 and pH Upon the Pulmonary Alveolar Macrophage

Much of the in vivo research that has been conducted on the health effects of pollutants such as SO₂ and NO₂ has been concerned with their effects upon lung defense systems, with particular reference to their effect on functional properties of the alveolar macrophage (AM). The lungs are constantly exposed to the external environment with its variable content of irritants and infectious agents. Agents deposited in or below the region of the respiratory bronchioles are phagocytized by the AM. The specific capacity of the AM to perform its task is subject to many factors. Gaseous air pollutants have been shown to affect the functional state of the cells^(1). Phagocytosis is an energy dependent process and plasma membrane ATPase has been suggested to act as a mechanoenzyme making phagocytosis possible through the conversion of chemical energy in the form of ATPase to the mechanical energky required for attachement and ingestion ⁽²⁾. Since the bulk of the cellular ATPase activity is located in the plasma membrane of the AM⁽³⁾ the enzyme is easily accessible to inhaled pollutants. Furthermome, the activity of ATPase and other membrane bound enzymes is well know to be dependent upon the fluidity of membrane lipids.     

Irreducibility of Toeplitz C⋆-algebras

We probe the irreducibility of the Toeplitz C^*-algebras generated by Toeplitz operators on Bergman and Hardy spaces associated with generalized upper half-planes in several complex variables.     

Tangible convex bodies. Appendix to “Multivariable Wiener-Hopf Operators I”

Study in a local geometry of non-smooth convex bodies via their supporting cones. The supporting cones are differential objects if the convex bodies are tangible. Examples of completely tangible and non-tangible convex bodies are presented.     

CO Oxidation Catalytic Effects of Intrinsic Surface Defects in Rhombohedral LaMnO3

There is an ongoing effort to replace rare and expensive noble-element catalysts with more abundant and less expensive transition metal oxides. With this goal in mind, the intrinsic defects of a rhombohedral perovskite-like structure of LaMnO₃ and their implications on CO catalytic properties were studied. Surface thermodynamic stability as a function of pressure (P) and temperature (T) were calculated to find the most stable surface under reaction conditions (P=0.2 atm, T=323 K to 673 K). Crystallographic planes (100), (111), (110), and (211) were evaluated and it was found that (110) with MnO₂ termination was the most stable under reaction conditions. Adsorption energies of O₂ and CO on (110) as well as the effect of intrinsic defects such as Mn and O vacancies were also calculated. It was found that O vacancies favor the interaction of CO on the surface, whereas Mn vacancies can favor the formation of carbonate species.