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The kinetic occipital (KO) region in man: an fMRI study 总被引:10,自引:8,他引:2
Van Oostende S; Sunaert S; Van Hecke P; Marchal G; Orban GA 《Cerebral cortex (New York, N.Y. : 1991)》1997,7(7):690-701
We used functional magnetic resonance imaging to explore, in individual
subjects, the properties of the kinetic occipital (KO) region, which
previous position emission tomography studies have shown to be involved in
the processing of kinetic boundaries. The KO region was significantly
activated in 23/25 subjects tested in the subtraction of uniform motion
from kinetic gratings. The KO region is genuinely specialized for
processing kinetic boundaries since it is significantly more activated by
kinetic gratings than by luminance-defined gratings, uniform motion or
transparent motion. This leaves only the kinetic boundaries, created by
discontinuities in motion direction, as the specific stimulus aspect,
activating the KO region. The KO region is anatomically and functionally
distinct from areas MT/V5, V3 and V3A. It also has minimal overlap with the
lateral occipital (LO) region. The selective activation of the KO region is
robust and relatively immune to changes in stimulus size, spatial frequency
and type of kinetic boundary. These results strongly argue for the view
that the KO region is a new, separate, functional region in human occipital
cortex.
相似文献
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Electron microscopic evidence of persistent chlamydial infection following treatment 总被引:4,自引:0,他引:4
EY Bragina † MA Gomberg ‡ GA Dmitriev† 《Journal of the European Academy of Dermatology and Venereology》2001,15(5):405-409
Chlamydia trachomatis infections of the female and male genital tracts are often asymptomatic and, thus, tend to become persistent. In the persistent state the typical Chlamydia life cycle is arrested and standard antibiotic regimens do not always eradicate this infection. We sought to relate treatment failures in men and women with persistent chlamydial genital tract infections to electron microscopic evidence of chlamydial persistence and with atypical morphological forms of the organism. Of 16 patients with chlamydial persistence following azithromycin treatment, morphological variants of this organism were observed by electron microscopy from one endocervical sample and one male urethral sample. We document the presence of intracellular inclusions containing only reticulate bodies, extracellular monomembrane and polymembrane phagosomes containing elementary bodies and reticulate bodies with abnormal outer membranes in the process of dividing extracellularly. These observations parallel previous in vitro studies of chlamydial persistence under adverse conditions. This capacity of C. trachomatis to undergo atypical morphological alterations in vivo may contribute to its persistence and relative resistance to antibiotics. 相似文献
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Ghali JK Dunselman P Waagstein F Goldstein S Gottlieb SS Deedwania PC Wikstrand JC 《Journal of cardiac failure》2004,10(6):452-459
BACKGROUND: The effects of beta-blockade with different extent of angiotensin-converting enzyme inhibitors (ACEI) and digitalization are unknown. To assess the effect of metoprolol succinate controlled release/extended release (CR/XL) combined with high versus low doses of ACEI and digitalis, we analyzed data from The Metoprolol CR/XL Randomized Intervention Trial in Chronic Heart Failure (MERIT-HF) in which patients with heart failure and left ventricular ejection fraction < or =40% were randomized to metoprolol CR/XL versus placebo. METHODS AND RESULTS: Outcome was analyzed separately for those on a low dose (< or =median) of the ACEI or digitalis versus high dose (> median). The mean dose of ACEI in the high-dose group (n = 1457) was 3 times higher than that in the low-dose group (n = 2094). Mortality was reduced to a similar extent in the high- and low-dose ACEI subgroups (RR = .69 versus .64, respectively). Corresponding figures for combined mortality/all hospitalization and for mortality/hospitalization for heart failure were .85 versus .83, and .70 versus .68, respectively. Likewise, reduction in total mortality with metoprolol CR/XL was similar in patients receiving no digitalis (n = 1447; RR = .56), low dose (n = 1122; RR = .71), or high dose (n = 1421; RR = .71). CONCLUSION: This analysis of MERIT-HF demonstrates consistent and similar improvement in outcome of patients receiving metoprolol CR/XL when combined with either a high or low dose of an ACEI or digitalis, or no digitalis at all. Thus regardless of ACEI and digitalis dose and whether patients are treated with digitalis or not, it is very important to add a beta-blocker to the existing heart failure therapy. beta-blockers should not be withheld until target doses of ACEI have been achieved. 相似文献
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