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31.
The objectives of this study were to use computer-generated phantoms containing real subject motion to: (1) compare the sensitivity of four commonly used fMRI software packages and (2) compare the sensitivity of three statistical analysis strategies with respect to motion correction. The results suggest that all four packages perform similarly in fMRI statistical analysis with SPM2 having slightly higher sensitivity. The most sensitive analysis technique was to perform motion correction and include the realignment parameters as regressors in the general linear model. This approach applies to all four packages examined and can be most beneficial when stimulus-correlated motion is present.  相似文献   
32.
Idiopathic Parkinson's disease (PD) may possibly be caused by one or more unidentified neurotoxins present in the environment, or formed endogenously, which progressively damage dopaminergic nigrostriatal neurons. N-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is an experimental neurotoxin which produces biochemical and neuropathological changes in humans, lower primates and mice that closely resemble those found in PD. Because the mechanisms of neuronal damage in both idiopathic PD and in the MPTP model of PD may involve free radical formation in the substantia nigra, antioxidants might protect dopaminergic neurons. Previously, we found that both alpha-tocopherol and beta-carotene partially protected mice against MPTP. However, in the experiments described in this paper, neither alpha-tocopherol nor beta-carotene, each administered in massive doses, had any demonstrable protective effect for dopaminergic nigrostriatal neurons in marmosets injected with low doses of MPTP. Without more knowledge about the identity of the neurotoxin(s) causing idiopathic PD, and their mechanism of action, it is not possible at this time to predict whether these 2 antioxidants might be clinically useful in preventing or ameliorating PD.  相似文献   
33.
随着教育制度的改革,中职院校的学生面貌发生了巨大变化。面对新形势,我们应科学借鉴先进的教育理念,合理设置教育目标,为职业教育改革注入新的理念和活力。  相似文献   
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通过观察益肾化浊注射液对5/6肾切除大鼠残余肾中细胞因子含量的影响,益肾化浊注射液延缓慢性肾功能衰竭(CRF)模型大鼠肾功能减退的作用机理。结果显示:益肾化浊注射液可以降低5/6肾切在鼠血清肌,尿素氮(P<0.01),下调肾组织中白细胞介素-1(IL-1)(P<0.05),白细胞介素-8(IL-8)(P<0.05)及肿瘤坏死因子(TNF)(P<0.05)的总体水平,说明益肾化浊注射液可以通过下调5/6肾切除大鼠残余肾中相关细胞因子含量,抑制促炎细胞因子对肾脏的损害,从而延缓CRF的进展。  相似文献   
36.
Immunoscintigraphy with radiolabelled monoclonal antibodies is widely used to detect solid tumours, but only a few trials have been carried out concerning the specific in vivo localization of an inflammatory process. The purpose of this study was to investigate the detectability of tuberculous foci utilizing this method with radiolabelled bacillus Calmette-Guérin (BCG)-specific F(ab')2 in rabbits. All of the tuberculous lesions (n = 8) were clearly visualized on serial scintigraphy for up to 48 h after injection of the antibody. Immunohistochemical and Ziel-Neelson staining of the tuberculous lesions confirmed the presence of the tuberculous antigens and bacilli. It failed to demonstrate any sustained retention of the BCG-specific antibody fragment in the control group with syphilitic orchitis (n = 2). Therefore, the specific in vivo localization of tuberculosis is feasible by immunoscintigraphy.  相似文献   
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目的提出对学习策略和教学方式的改进建议。方法测试口腔医学生的场依存/独立认知风格,并用统计学方法分析其与口腔正畸学学习成绩的关系。结果①场独立认知风格是口腔医学专业学生认知风格的主体;②不同性别口腔医学专业学生的场依存/独立认知风格无显著性差异;③学生场依存/独立认知风格与口腔正畸学理论考试成绩有负相关倾向,与口腔正畸学实习操作成绩有正相关倾向。结论学习策略和教学方式因受认知风格的影响而制约学生学习的效果。  相似文献   
39.
The proliferative potential of low-grade astrocytomas was estimated in 47 patients. Each patient received an intravenous infusion of bromodeoxyuridine (BUdR), 150 to 200 mg/sq m, at the time of craniotomy to label cells in deoxyribonucleic acid (DNA) synthesis; the percentage of S-phase cells, or BUdR labeling index (LI), of each tumor was determined immunohistochemically. In 29 patients (60%), the tumors had BUdR LI's of less than 1%, indicating a slow growth rate; only three (10%) of these patients died of recurrent tumor during a follow-up period of up to 3 1/2 years. In contrast, of the 18 patients (40%) whose tumors had BUdR LI's of 1% or more, 12 (67%) had a recurrence and nine died during the same follow-up period. These results show that the proliferative potential, as reflected by the BUdR LI, is an important prognostic factor that separates low-grade astrocytomas into two groups and provides a more scientific rationale for selecting treatment for individual patients.  相似文献   
40.
Objective:To investigate the relationship between antibiotic administration and the changes in bacteriological profile in a burn unit. Methods: The data of consumption of different kinds of antibiotics, including total antibiotic consumption [expressed as the number of defined daily doses (DDD)] as well as pathogen identification, were collected in a 8-year period. The constituent ratios of different kinds of antibiotics in total antibiotic consumption to isolation rates of various species of bacteria were calculated, and their correlation was analyzed. Results: Within this period, it was found that the aminoglycosides and first generation cephalosporins were used less frequently, while the polypeptides, carbopenem and macrolides were used proportionally more. At the same time, the isolation rates of Staphylococcus aureus, Acinetobacter sp, Enterobacter cloacae, Klebsiella pneumoniae and methicillin-resistant Staphylococcus aureus were gradually increased. The constituent ratios of predominant pathogens were correlated to the different kinds of antibiotics consumption in the burn unit. Conclusion: The results suggested that the consumption of different antibiotics was closely related to the trends of emergence of bacterial isolates from infected burn wounds. The result might imply that to regulate the administration of certain antibiotics might help decrease the emergence of certain pathogenic bacteria in burn infections.  相似文献   
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