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Robin M Heidemann Mark A Griswold Nicole Seiberlich Mathias Nittka Stephan A R Kannengiesser Berthold Kiefer Peter M Jakob 《Magnetic resonance in medicine》2007,57(6):1037-1046
MRI with non-Cartesian sampling schemes can offer inherent advantages. Radial acquisitions are known to be very robust, even in the case of vast undersampling. This is also true for 1D non-Cartesian MRI, in which the center of k-space is oversampled or at least sampled at the Nyquist rate. There are two main reasons for the more relaxed foldover artifact behavior: First, due to the oversampling of the center, high-energy foldover artifacts originating from the center of k-space are avoided. Second, due to the non-equidistant sampling of k-space, the corresponding field of view (FOV) is no longer well defined. As a result, foldover artifacts are blurred over a broad range and appear less severe. The more relaxed foldover artifact behavior and the densely sampled central k-space make trajectories of this type an ideal complement to autocalibrated parallel MRI (pMRI) techniques, such as generalized autocalibrating partially parallel acquisitions (GRAPPA). Although pMRI can benefit from non-Cartesian trajectories, this combination has not yet entered routine clinical use. One of the main reasons for this is the need for long reconstruction times due to the complex calculations necessary for non-Cartesian pMRI. In this work it is shown that one can significantly reduce the complexity of the calculations by exploiting a few specific properties of k-space-based pMRI. 相似文献
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Both in open and in closed elbow fractures, anatomical joint reconstruction and rigid internal fixation, which permit early initiation of motion, are essential for good joint function. However, in open distal intraarticular humerus fractures this is more difficult to achieve, owing to the high rate of comminuted types C 2 and C 3 fractures. In addition, the extensive soft tissue lesions often mean that physiotherapy cannot be started until later than would otherwise be desirable. This retrospective study shows that the functional results in 60 patients operated on for correction of open distal intraarticular humerus fractures were worse (1/3 "excellent/good", 2/3 "moderate/poor") than those in patients treated for closed fractures. Complications included superficial infection in 7 patients, osteitis in 11, late instability in 10, fatigue failure of the implants in 5, and non-union in 10 patients. 相似文献
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130 medical and 130 administrative heads were asked to fill in a structured questionnaire to obtain an assessment of meals provided in Austrian hospitals. 62 questionnaires in each group were returned fully completed. Meals: ?S 46,--are available per patient and day; whereby the costs of special diets are ?S 11,--higher on average per day. Diets on offer: 96.8% of the questioned hospitals offered a diabetes diet; 95.2% a weight-reducing diet, 93.5% a light balanced diet and diet for patients with hyperlipidaemia and 90.3% a reduced salt diet (the worst accepted by the patients). 90.3% of these hospitals would consider dietary recommendations as a preventive measure. In fact, preventive dietary measure are implemented in 75.5% of the hospitals questioned. It was apparent that the staff in charge are aware of the influence of correct-nutrition in hospitals. It is recommended that nutritional advice should be offered more often in all wards (this is at present available in only 8.0% of the hospitals). It should be mentioned that financial resources concerning hospital meals should be increased for the more widespread establishment of "healthy food", too. 相似文献
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Macrophage response to peripheral nerve injury: the quantitative contribution of resident and hematogenous macrophages 总被引:6,自引:0,他引:6
Mueller M Leonhard C Wacker K Ringelstein EB Okabe M Hickey WF Kiefer R 《Laboratory investigation; a journal of technical methods and pathology》2003,83(2):175-185
Whereas local microglial cells of the CNS rapidly respond to injury, little is known about the functional role of resident macrophages of the peripheral nervous system in nerve pathology. Using bone marrow chimeric rats, we recently identified individual resident endoneurial macrophages that rapidly became activated after nerve injury. However, the extent of local macrophage activation and its quantitative contribution to the total macrophage response is unknown. We now have created chimeric mice by transplanting bone marrow from green fluorescent protein (GFP)-transgenic mice into irradiated wild-type mice, allowing easy differentiation and quantification of hematogenous and resident endoneurial macrophages. After sciatic nerve crush injury, both GFP(-) and GFP(+) resident macrophages, the latter having undergone physiological turnover from the blood before injury, rapidly underwent morphological alterations and increased in number. Proliferating GFP(-) and GFP(+) resident macrophages were abundant and peaked 3 days after injury. A major lesion-induced influx of hematogenous macrophages with a disproportionate increase of GFP(+) macrophages was not observed until Day 4. Throughout all time points examined, GFP(-) resident macrophages were strikingly frequent, reaching maximum numbers 9.5-fold above baseline. There was also a notable proportion of GFP(-) resident endoneurial macrophages phagocytosing myelin and expressing major histocompatibility complex class II. Our results demonstrate for the first time that the rapid response of resident endoneurial macrophages to nerve injury is quantitatively important and that local macrophages contribute significantly to the total endoneurial macrophage pool during Wallerian degeneration. 相似文献
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Charles R. Kiefer James B. McKenney Jane F. Trainor Richard W. Lambrecht Herbert L. Bonkovsky Lawrence M. Lifshitz C. Robert Valeri L. Michael Snyder 《The American journal of pathology》1998,153(3):703-708
To further the understanding of oxidative effects on inflammation injury to muscle fiber structure, fluorescent imaging analysis of human striated muscle tissues from a variety of inflammatory or postinflammatory etiologies was undertaken in a search for accumulated coproporphyrin, a red autofluorescent byproduct of heme biosynthesis that would theoretically be formed under oxidative insult. Using a differential excitation method of in situ analysis, porphyrin autofluorescence was detected in intact fibers within the context of the yellow autofluorescent subsarcolemmal lipofuscin granules. Relative measurements of porphyrin concentration in the granules from different patients indicated that the acute/subacute inflammatory specimens grouped significantly higher than the more chronic inflammatory and nonpathological specimens. Myoglobin was also found to be associated with the granules. Myoglobin heme iron could potentially serve as a Fenton reagent for the intracellular generation of hydroxyl radicals, which are responsible for the oxidation of the porphyrinogens. High-performance liquid chromatography analysis of extracted dense particles revealed coproporphyrin as the sole porphyrin present. The observation of coproporphyrin within lipofuscin granules, previously unreported, suggests that lipofuscin accumulation in striated muscle may begin under conditions of acute oxidative stress, as marked by the oxidation of extramitochondrial porphyrinogens that are immediately incorporated into the granules. 相似文献
8.
Outbreak of serogroup C meningococcal disease caused by a variant of Neisseria meningitidis serotype 2a ET-15 in a community of men who have sex with men
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Tsang RS Kiefer L Law DK Stoltz J Shahin R Brown S Jamieson F 《Journal of clinical microbiology》2003,41(9):4411-4414
We describe an outbreak, in a community of men who have sex with men, of serogroup C meningococcal disease caused by a genetic variant of the serotype 2a ET-15 Neisseria meningitidis characterized by a point mutation in the gene coding for the serotype 2a antigen. A microbiological characterization of the outbreak strain is presented in this report. 相似文献
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Perceived failure is reported to have detrimental effects on subsequent performance in patients with major depressive disorder. We investigated the error-related negativity (ERN)/error negativity (Ne), an electrophysiological correlate of response monitoring, using a 64-channel EEG. Sixteen patients with DSM-IV major depressive disorder and 16 matched controls participated in an Eriksen flanker task with continuous performance feedback that signaled monetary reward. Compared to controls, patients with major depressive disorder showed a less negative ERN/Ne in error trials following error trials. This result might reflect impaired response monitoring processes in major depressive disorder resulting from an underactivity in a central reward pathway and/or a deficit in strategic reasoning. 相似文献