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ME Lauer 《Acta paediatrica (Oslo, Norway : 1992)》1997,86(10):1037-1039
Reports have begun to proliferate throughout the world which describe various models of pediatric hospice care. While encouraging, these reports identify universal obstacles that continue to compromise effective care. Challenges persist in areas of pain management, medical ethics, program administration, cost analysis, staff development and bereavement follow-up. Cooperative efforts are encouraged to address these issues. 相似文献
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褪黑素对小鼠免疫性肝损伤的保护作用 总被引:12,自引:2,他引:10
目的观察褪黑素(MT)对小鼠免疫性肝损伤的影响。方法序贯注射短小棒状杆菌和脂多糖诱导小鼠免疫性肝损伤模型;在造模不同时间注射不同剂量MT;检测血浆转氨酶、肝脏雨二醛(MDA)和谷胱甘肽过氧化物酶(GSH-px)以及脾淋巴细胞增殖状况。结果造模期间用MT(0.1~10.0mg·kg-1)能显著降低血浆转氨酶和肝脏MDA水平(P<0.05~0.01),使肝脏GSH-px活性部分恢复(P<0.05),并能选择性抑制刀豆蛋白A诱导的脾淋巴细胞增殖。但造模后使用MT对免疫性肝损伤无明显影响。结论MT保护免疫性肝损伤作用与其抗氧化和免疫调节作用有关。 相似文献
147.
Diabetic retinopathy remains a major cause of loss of vision. The Diabetes Control and Complications Trial (DCCT) has implicated hyperglycaemia as a probable major direct causative factor in the pathogenesis of diabetic retinopathy. There are several plausible mechanisms by which high glucose concentrations could lead to the functional and later structural changes characterising diabetic retinopathy. These include increased activity of the aldose reductase pathway, increase de novo synthesis of diacylglycerol from glucose, causing protein kinase C activation, increased non-enzymatic glycation and increased oxidative damage. The demonstration of the potential roles of these pathways and the subsequent effects of growth factors in enhancing angiogenesis provide potential new approaches to the prevention and treatment of diabetic retinopathy. 相似文献
148.
High-resolution EEG mapping of cortical activation related to working memory: effects of task difficulty, type of processing, and practice 总被引:13,自引:7,他引:6
Changes in cortical activity during working memory tasks were examined with
electroencephalograms (EEGs) sampled from 115 channels and spatially
sharpened with magnetic resonance imaging (MRI)-based finite element
deblurring. Eight subjects performed tasks requiring comparison of each
stimulus to a preceding one on verbal or spatial attributes. A frontal
midline theta rhythm increased in magnitude with increased memory load.
Dipole models localized this signal to the region of the anterior cingulate
cortex. A slow (low-frequency), parietocentral, alpha signal decreased with
increased working memory load. These signals were insensitive to the type
of stimulus attribute being processed. A faster (higher-frequency),
occipitoparietal, alpha signal was relatively attenuated in the spatial
version of the task, especially over the posterior right hemisphere. Theta
and alpha signals increased, and overt performance improved, after practice
on the tasks. Increases in theta with both increased task difficulty and
with practice suggests that focusing attention required more effort after
an extended test session. Decreased alpha in the difficult tasks indicates
that this signal is inversely related to the amount of cortical resources
allocated to task performance. Practice-related increases in alpha suggest
that fewer cortical resources are required after skill development. These
results serve: (i) to dissociate the effects of task difficulty and
practice; (ii) to differentiate the involvement of posterior cortex in
spatial versus verbal tasks; (iii) to localize frontal midline theta to the
anteromedial cortex; and (iv) to demonstrate the feasibility of using
anatomical MRIs to remove the blurring effect of the skull and scalp from
the ongoing EEG. The results are discussed with respect to those obtained
in a prior study of transient evoked potentials during working memory.
相似文献
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J R Dunbar A J DeLucia R V Acuff K E Ferslew 《Toxicology and applied pharmacology》1988,94(2):221-226
The effects of paraquat (PQ) on lung putrescine, spermidine, and spermine levels, and ornithine decarboxylase (ODC) activity were assessed in rats after 7 days of iv infusion of the herbicide via osmotic minipump. Paraquat administration at a rate of 250 nmol/hr [673 +/- 40 nmol/kg/hr (n = 15)] had no effect on these parameters. In contrast, significant (p less than 0.05) elevations in lung putrescine (407% of control), spermidine (202% of control), and ODC activity (174% of control were measured in lungs of rats given 500 nmol PQ/hr [1.31 +/- 0.53 mumol/kg/hr (n = 14)]. Since evidence of lung damage was, likewise, observed only in the high-dose PQ rats, these changes in polyamine metabolism could have been a nonspecific response to PQ-induced lung injury rather than a direct biochemical effect of PQ. The results suggest that stimulation of polyamine biosynthesis may play an important role in PQ-induced lung injury. This role may involve regulation of repair mechanisms or, conversely, the polyamines may actually mediate PQ-induced fibrotic changes in the lung. 相似文献