DM Parker  JR Lishman  J Hughes 《Canadian Metallurgical Quarterly》1996,22(6):1448-1466

In 4 experiments the role of coarse (low-pass filtered) and fine (high-pass filtered) spatial information in guiding visual processing was studied in a same-different task. The second of a pair of sequential patterns was either a normal image or the first 100 ms was restricted either coarse or fine information before a normal image was shown for the rest of the presentation. This 100-ms cue could be from the immediately succeeding image (relevant) or from other images in the set (irrelevant). Analysis of response times and errors showed relevant coarse- and fine-scale cues were usually equally effective, but any differences favored fine-scale versions. Irrelevant fine-scale cuing was significantly more disruptive than coarse-scale cuing. No evidence of preferential cuing by coarse-scale information occurred in any experiment.  相似文献   

    

RT Roy  JR Merril 《Canadian Metallurgical Quarterly》1996,83(9):634-638

With the advent of the World Wide Web (WWW), we are now on the cusp of a revolution in computer technology that will dramatically enhance medical education. An historical analogy might be Johann Gutenberg's invention of movable type in the 1400's-radically decreasing the cost, time, and expertise required to reproduce printed materials. Now, the WWW can decrease the cost of disseminating medical educational materials. When an educational module is authored for the Web, it can be placed on a computer \"server\" which in turn, distributes the program on the WWW to anyone with a computer and Internet access. Rapidly emerging standards are being developed to allow increasingly rich educational experiences on the Internet. With the introduction of HTML (hypertext markup language), a standardized method of placing text and graphics, as well as the connections between them, was created.  相似文献   

    

R Shen  LM Tillekeratne  JR Kirchhoff  RA Hudson 《Canadian Metallurgical Quarterly》1996,228(1):187-192

The purpose of this prospective study was to verify whether the percentage area of lung occupied by lowest attenuation values on high-resolution computed tomography (HRCT) scans reflects microscopic emphysema and to compare this quantification with the information yielded by the most widely used pulmonary function tests (PFT). Preoperative HRCT scans were obtained with 1-cm intervals in 38 subjects. With a semiautomatic evaluation procedure, the percentage areas occupied by attenuation values inferior to thresholds ranging from -900 Hounsfield units (HU) to -970 HU were calculated for the lobe or lung to be resected. Emphysema was microscopically quantified by using a computer-based method, measuring the perimeters and interwall distances of alveoli and alveolar ducts. The strongest correlation was found for -950 HU. As a second step, we evaluated possible correlations between PFT and microscopic measurements. Finally, considering the microscopic measurements as a standard, we tried to investigate their relationships with each of the PFT and with the relative area occupied by attenuation values lower than -950 HU for both lungs. This revealed that the diffusing capacity for carbon monoxide associated with HRCT quantification is sufficient to predict microscopic measurements. We concluded that the percentage area of lung occupied by attenuation values lower than -950 HU is a valid index of pulmonary emphysema.  相似文献   

    

SB Karwacki  JR Bradley 《Canadian Metallurgical Quarterly》1996,26(3):243-255

Associations between coping responses, drinking motivations, expectations of meeting social and academic goals, and family of origin problem drinking and measures of college students' quantity/frequency of alcohol use and social complications of alcohol use were investigated in a sample of 218 college students. Positive associations were found between \"emotion-focused\" forms of coping such as detachment and the criterion measures, whereas \"problem-focused coping\" was not significantly associated with quantity/frequency of alcohol use or drinking complications. Positive correlations were also found between drinking motives, goal attainment expectancies and family models measures and the criterion measures. Regression models constructed for alcohol quantity/frequency and drinking complications implicated the total number of drinking motives, family models of problem drinking and the coping strategy of self-blame as strongly related to criterion measures. Positive social drinking motives and coping by seeking social support were implicated as possible protective factors.  相似文献   

    

G Liuzzo  A Buffon  LM Biasucci  JR Gallimore  G Caligiuri  A Vitelli  S Altamura  G Ciliberto  AG Rebuzzi  F Crea  MB Pepys  A Maseri 《Canadian Metallurgical Quarterly》1998,98(22):2370-2376

BACKGROUND: Systemic markers of inflammation have been found in unstable angina. Disruption of culprit coronary stenoses may cause a greater inflammatory response in patients with unstable than those with stable angina. We assessed the time course of C-reactive protein (CRP), serum amyloid A protein (SAA), and interleukin-6 (IL-6) after single-vessel PTCA in 30 patients with stable and 56 patients with unstable angina (protocol A). We also studied 12 patients with stable and 15 with unstable angina after diagnostic coronary angiography (protocol B). METHODS AND RESULTS: Peripheral blood samples were taken before and 6, 24, 48, and 72 hours after PTCA or angiography. In protocol A, baseline CRP, SAA, and IL-6 levels were normal in 87% of stable and 29% of unstable patients. After PTCA, CRP, SAA, and IL-6 did not change in stable patients and unstable patients with normal baseline levels but increased in unstable patients with raised baseline levels (all P<0.001). In protocol B, CRP, SAA, and IL-6 did not change in stable angina patients after angiography but increased in unstable angina patients (all P<0.05). Baseline CRP and SAA levels correlated with their peak values after PTCA and angiography (all P<0.001). CONCLUSIONS: Our data suggest that plaque rupture per se is not the main cause of the acute-phase protein increase in unstable angina and that increased baseline levels of acute-phase proteins are a marker of the hyperresponsiveness of the inflammatory system even to small stimuli. Thus, an enhanced inflammatory response to nonspecific stimuli may be involved in the pathogenesis of unstable angina.  相似文献   

    

JR Chamberlain  Y Lee  WS Lane  DR Engelke 《Canadian Metallurgical Quarterly》1998,12(11):1678-1690

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H Ying  JF Chang  JR Parnes 《Canadian Metallurgical Quarterly》1998,160(5):2287-2296

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RC Ferreira  JR Heckenlively  JH Menkes  JB Bateman 《Canadian Metallurgical Quarterly》1998,105(6):1076-1078

OBJECTIVE: The authors describe new ocular and electroretinographic (ERG) features in Menkes disease. DESIGN: The study design is a case report. PARTICIPANTS: The authors studied two patients with Menkes disease. INTERVENTION: The authors performed complete ophthalmologic and ERG evaluations in both patients. MAIN OUTCOME MEASURES: The parameters used were slit-lamp biomicroscopy and ERG recordings. RESULTS: Aberrant lashes and anterior stromal hypoplasia of the iris are new findings, and profound delays in b-wave implicit time in well-developed photopic responses may be added as new ERG features. CONCLUSIONS: Patients with Menkes disease may have aberrant lashes, anterior stromal hypoplasia, and retinal degeneration.  相似文献   

    

CE Sortwell  BC Blanchard  TJ Collier  JD Elsworth  JR Taylor  RH Roth  DE Redmond  JR Sladek 《Canadian Metallurgical Quarterly》1998,791(1-2):117-124

The functional regulation by serotonin (5-HT) receptors of the 5-HT-enhanced dopamine (DA) release from the rat substantia nigra (SN) was investigated using in vivo microdialysis. Exogenously administered or extracellularly enhanced 5-HT (by means of intranigral citalopram perfusion) (both 1 microM for 1 h) significantly increased nigral DA efflux to 165% and 145%, respectively. Intranigral administration of pindolol (10 microM, 3 h), a 5-HT1A/1B receptor antagonist which is clinically used in order to block 5-HT1A/1B autoreceptors, did not affect DA levels but significantly increased nigral 5-HT levels to 135%. Co-perfusion of this antagonist with 5-HT (1 microM, 1 h) did not abolish the 5-HT-induced DA release from the SN as DA was increased to 166%. Local application of the 5-HT1A/1B receptor agonist, CP 93129 (1 microM, 1 h), increased DA release from the SN to 4770% whereas 5-HT release was significantly decreased to 75%. Co-perfusion of the 5-HT1A/1B receptor antagonist, pindolol, with this agonist only partly abolished the CP 93129-induced DA release whereas the CP 93129-induced decrease in nigral 5-HT release was completely abolished. Administration of the 5-HT2A/2C receptor antagonist, ketanserin (50 microM, 3 h), significantly increased DA to 143% and 5-HT release to 363%. Co-perfusion of this antagonist with 5-HT still caused an increase in nigral DA release to 214%. Intranigral perfusion of the 5-HT4 receptor antagonist, RS 39604 (10 microM, 3 h), did not affect DA levels but significantly decreased nigral 5-HT levels to 74%. Co-perfusion of this antagonist with 5-HT was able to prevent the 5-HT-enhanced DA efflux from the SN. From this study it can be concluded that the 5-HT-enhanced (and possibly the citalopram-induced) nigral DA release is 5-HT4 receptor mediated.  相似文献   

    

GJ Wang  M Collinge  F Blasi  R Pardi  JR Bender 《Canadian Metallurgical Quarterly》1998,95(11):6296-6301

As an adhesion receptor, the beta2 integrin lymphocyte function-associated antigen-1 (LFA-1) contributes a strong adhesive force to promote T lymphocyte recirculation and interaction with antigen-presenting cells. As a signaling molecule, LFA-1-mediates transmembrane signaling, which leads to the generation of second messengers and costimulation resulting in T cell activation. We recently have demonstrated that, in costimulatory fashion, LFA-1 activation promotes the induction of T cell membrane urokinase plasminogen activator receptor (uPAR) and that this induced uPAR is functional. To investigate the mechanism(s) of this induction, we used the RNA polymerase II inhibitor 5, 6-dichloro-1-beta-D-ribobenzimidazole and determined that uPAR mRNA degradation is delayed by LFA-1 activation. Cloning of the wild-type, deleted and mutated 3'-untranslated region of the uPAR cDNA into a serum-inducible rabbit beta-globin cDNA reporter construct revealed that the AU-rich elements and, in particular the nonameric UUAUUUAUU sequence, are crucial cis-acting elements in uPAR mRNA degradation. Experiments in which Jurkat T cells were transfected with reporter constructs demonstrated that LFA-1 engagement was able to stabilize the unstable reporter mRNA containing the uPAR 3'-untranslated region. Our study reveals a consequence of adhesion receptor-mediated signaling in T cells, which is potentially important in the regulation of T cell activation, including production of cytokines and expression of proto-oncogenes, many of which are controlled through 3' AU-rich elements.  相似文献