Changes in left atrial deformation in hypertrophic cardiomyopathy: Evaluation by vector velocity imaging.

OBJECTIVES: Hypertrophic cardiomyopathy (HCM) represents a generalized myopathic process affecting both ventricular and atrial myocardium. We assessed the global and regional left atrial (LA) function and its relation to left ventricular (LV) mechanics and clinical status in patients with HCM using Vector Velocity Imaging (VVI). METHODS: VVI of the LA and LV was acquired from apical four- and two-chamber views of 108 HCM patients (age 40 ± 19years, 56.5% men) and 33 healthy subjects, all had normal LV systolic function. The LA subendocardium was traced to obtain atrial volumes, ejection fraction, velocities, and strain (ϵ)/strain rate (SR) measurements. RESULTS: Left atrial reservoir (ϵsys,SRsys) and conduit (early diastolic SRe) function were significantly reduced in HCM compared to controls (P  - 1.8s(- 1) was 81% sensitive and 30% specific, SRa> - 1.5s(- 1) was 73% sensitive and 40% specific. By multivariate analysis global LVϵsys and LV septal thickness are independent predictors for LAϵsys, while end systolic diameter is the only independent predictor for SRsys, P < .001. CONCLUSION: Left atrial reservoir and conduit function as measured by VVI were significantly impaired while contractile function was preserved among HCM patients. Left atrial deformation was greatly influenced by LV mechanics and correlated to severity of phenotype

Theory of disk accretion onto supermassive black holes

Accretion onto supermassive black holes produces both the dramatic phenomena associated with active galactic nuclei and the underwhelming displays seen in the Galactic Center and most other nearby galaxies. I review selected aspects of the current theoretical understanding of black hole accretion, emphasizing the role of magnetohydrodynamic turbulence and gravitational instabilities in driving the actual accretion and the importance of the efficacy of cooling in determining the structure and observational appearance of the accretion flow. Ongoing investigations into the dynamics of the plunging region, the origin of variability in the accretion process, and the evolution of warped, twisted, or eccentric disks are summarized.Comment: Mostly introductory review, to appear in "Supermassive black holes in the distant Universe", ed. A.J. Barger, Kluwer Academic Publishers, in pres

The V471A polymorphism in autophagy-related gene ATG7 modifies age at onset specifically in Italian Huntington disease patients

The cause of Huntington disease (HD) is a polyglutamine repeat expansion of more than 36 units in the huntingtin protein, which is inversely correlated with the age at onset of the disease. However, additional genetic factors are believed to modify the course and the age at onset of HD. Recently, we identified the V471A polymorphism in the autophagy-related gene ATG7, a key component of the autophagy pathway that plays an important role in HD pathogenesis, to be associated with the age at onset in a large group of European Huntington disease patients. To confirm this association in a second independent patient cohort, we analysed the ATG7 V471A polymorphism in additional 1,464 European HD patients of the “REGISTRY” cohort from the European Huntington Disease Network (EHDN). In the entire REGISTRY cohort we could not confirm a modifying effect of the ATG7 V471A polymorphism. However, analysing a modifying effect of ATG7 in these REGISTRY patients and in patients of our previous HD cohort according to their ethnic origin, we identified a significant effect of the ATG7 V471A polymorphism on the HD age at onset only in the Italian population (327 patients). In these Italian patients, the polymorphism is associated with a 6-years earlier disease onset and thus seems to have an aggravating effect. We could specify the role of ATG7 as a genetic modifier for HD particularly in the Italian population. This result affirms the modifying influence of the autophagic pathway on the course of HD, but also suggests population-specific modifying mechanisms in HD pathogenesis

High Level Resistance of Enterococcus faecium and E. faecalis Isolates from Municipal Sewage Treatment Plants to Gentamicin

Background: Enterococci are members of the normal gut flora and released into the environment via sewage outlets, where they can survive for long times. Infections with high-level gentamicin resistant (HLGR) enterococci are emerg&amp;shy;ing worldwide. HLGR enterococci have developed a resistance to most antibiotics commonly used for enterococcal in&amp;shy;fec&amp;shy;tions therefore; treatment of infections caused by HLGR enterococci is difficult. The present study investigated the dis&amp;shy;tribution and antibiotic resistance of HLGR Enterococcus faecium and E. faecalis isolates from raw wastewater sam&amp;shy;ples in Tehran.Methods: Raw wastewater samples were collected during the period from November 2006 to May 2007 at 3 sewage treat&amp;shy;ment plants located in different parts of Tehran. All 90 HLGR enterococcal isolates were identified to the species level by biochemical and PCR assays and subjected to antibiotic susceptibility testing. Results: Sixty four percent (58 of 90) of isolates were E. faecium and 29%(26 of 90) of them were E. faecalis. The high&amp;shy;est level of antibiotic resistance was observed with erythromycin (63%), co-trimoxazole (69%) and tetracycline (92%) for E.faecalis and with erythromycin (97%), ciprofloxacin (47%), co-trimoxazole (45.5%) and tetracycline (47%) for E. faecium. Multiresistance against 3 to 4 antimicrobial was present in 27.5% and 15.5% of the isolates, re&amp;shy;spectively. Conclusion: HLGR E. faecium were more commonly found than E. faecalis. Species identification of HLGR entero&amp;shy;cocci enables us to assess species-specific antibiotic susceptibility patterns in our area. The present study reviled that HLGR E. faecalis remained more susceptible than E. faecium against the usual first-line and alternative treatments