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91.
92.
The efficacy of diagnostic imaging 总被引:21,自引:0,他引:21
The authors discuss the assessment of the contribution of diagnostic imaging to the patient management process. A hierarchical model of efficacy is presented as an organizing structure for appraisal of the literature on efficacy of imaging. Demonstration of efficacy at each lower level in this hierarchy is logically necessary, but not sufficient, to assure efficacy at higher levels. Level 1 concerns technical quality of the images; Level 2 addresses diagnostic accuracy, sensitivity, and specificity associated with interpretation of the images. Next, Level 3 focuses on whether the information produces change in the referring physician's diagnostic thinking. Such a change is a logical prerequisite for Level 4 efficacy, which concerns effect on the patient management plan. Level 5 efficacy studies measure (or compute) effect of the information on patient outcomes. Finally, at Level 6, analyses examine societal costs and benefits of a diagnostic imaging technology. The pioneering contributions of Dr. Lee B. Lusted in the study of diagnostic imaging efficacy are highlighted. 相似文献
93.
Suppression of peroxisomal membrane protein defects by peroxisomal ATP binding cassette (ABC) proteins 总被引:8,自引:4,他引:4
Braiterman LT; Zheng S; Watkins PA; Geraghty MT; Johnson G; McGuinness MC; Moser AB; Smith KD 《Human molecular genetics》1998,7(2):239-247
X-Linked adrenoleukodystrophy (X-ALD) is a neurodegenerative disorder
characterized by reduced peroxisomal very long chain fatty acid (VLCFA)
beta-oxidation. The X - ALD gene product (ALDP) is a peroxisomal
transmembrane protein with an ATP binding cassette (ABC). ALDP and three
other ABC proteins (PMP70, ALDR, P70R) localize to the peroxisomal
membrane. The function of this family of peroxisomal membrane proteins is
unknown. We used complementation studies to begin analysis of their role in
VLCFA beta-oxidation and on the peroxisomal membrane. Expression of either
ALDP or PMP70 restores VLCFA beta- oxidation in X-ALD fibroblasts,
indicating overlapping functions. Their expression also restores peroxisome
biogenesis in cells that are deficient in the peroxisomal membrane protein
Pex2p. Thus it is likely that complex protein interactions are involved in
the function and biogenesis of peroxisomal membranes that may contribute to
disease heterogeneity.
相似文献
94.
Steinsapir KD Goldberg RA Sinha S Hovda DA 《Journal of the peripheral nervous system : JPNS》2002,7(2):136-136
The excitability of human axons can be studied reliably using the technique of threshold tracking, which allows the strength of a test stimulus to be adjusted by computer to activate a defined fraction of the maximal nerve or muscle action potential. The stimulus current that just evokes the target response is considered the 'threshold' for that response. More useful than the resting threshold are other indices of axonal excitability derived from pairs of threshold measurements, such as refractoriness, supernormality, strength-duration time constant and 'threshold electrotonus' (i.e. the changes in threshold produced by long-lasting depolarizing or hyperpolarizing current pulses). Each of these measurements depends on membrane potential and on other biophysical properties of the axons. Together they can provide new information about the pathophysiology underlying abnormalities in excitability in neuropathy. 相似文献
95.
Coates CG Denvir DJ McHale NG Thornbury KD Hollywood MA 《Journal of biomedical optics》2004,9(6):1244-1252
The back-illuminated electron multiplying charge-coupled device (EMCCD) camera is having a profound influence on the field of low-light dynamic cellular microscopy, combining highest possible photon collection efficiency with the ability to virtually eliminate the readout noise detection limit. We report here the use of this camera, in 512 x 512 frame-transfer chip format at 10-MHz pixel readout speed, in optimizing a demanding ultra-low-light intracellular calcium flux microscopy setup. The arrangement employed includes a spinning confocal Nipkow disk, which, while facilitating the need to both generate images at very rapid frame rates and minimize background photons, yields very weak signals. The challenge for the camera lies not just in detecting as many of these scarce photons as possible, but also in operating at a frame rate that meets the temporal resolution requirements of many low-light microscopy approaches, a particular demand of smooth muscle calcium flux microscopy. Results presented illustrate both the significant sensitivity improvement offered by this technology over the previous standard in ultra-low-light CCD detection, the GenIII+intensified charge-coupled device (ICCD), and also portray the advanced temporal and spatial resolution capabilities of the EMCCD. 相似文献
96.
Pseudomembranous colitis: CT evaluation of 26 cases 总被引:3,自引:0,他引:3
Fishman EK; Kavuru M; Jones B; Kuhlman JE; Merine DS; Lillimoe KD; Siegelman SS 《Radiology》1991,180(1):57
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