金丝桃甙的合成研究

金丝桃甙的合成研究蒋忠良，朱胄远，伍越环，王钟，周维善（中国科技大学化学系，合肥２３００２６；中国科学院上海有机化学研究所，上海２０００３２）金丝桃甙（Ⅰ）有抗过敏、解痉、抗胃溃疡和利尿等作用，且有显著止咳，降血压，降低胆固醇效果，无副作用（１～３）...     

Evaluation of QUADAS, a tool for the quality assessment of diagnostic accuracy studies

Background  

In clinical trials, both unequal randomization design and sequential analyses have ethical and economic advantages. In the single-stage-design (SSD), however, if the sample size is not adjusted based on unequal randomization, the power of the trial will decrease, whereas with sequential analysis the power will always remain constant. Our aim was to compare sequential boundaries approach with the SSD when the allocation ratio (R) was not equal.     

DEMYELINATION INDUCED IN MICE BY AVIRULENT SEMLIKI FOREST VIRUS. II. AN ULTRASTRUCTURAL STUDY OF FOCAL DEMYELINATION IN THE BRAIN

Four-week-old mice were infected intraperitoneally with an avirulent strain A7(74) of Semliki Forest virus (SFV) and killed at 4, 10, 15, 21 and 29 days after inoculation. Focal demyelinating lesions were present by 10 days. These were usually accompanied by a mononuclear infiltrate which included lymphocytes possessing characteristic cytoplasmic projections. These latter extended deep into the cytoplasm of adjacent cells, which were usually astrocytes and macrophages. Other features of the focal lesions were expansion of the extracellular space and demyelination which appeared to be fragmentation or lysis rather than stripping of myelin by macrophages. Although healing occurred in some mice after 4 weeks, acute lesions were still found in others of the same age. It was concluded that the demyelination probably had an immunological basis, and interaction between elements of the immune system and glial cells was a factor which inhibited orderly remyelination of the relatively mild lesions resulting from this infection.     

The behaviour of meningeal cells following glial cell transplantation into chemically-induced areas of demyelination in the CNS

Following transplantation of cultures of CNS glia containing leptomeningeal cells into ethidium bromide-induced demyelinating lesions, meningeal cells adopt either compacted or diffuse arrangements. The compacted arrangements involved no interactions with other cellular components of the remyelinating environment, and were particularly prominent following transplantation of cultures containing a high proportion of fibronectin-positive meningeal cells. The diffuse arrangements involved interactions with astrocytes, Schwann cells and endothelial cells, and contributed to a fragmented appearance of the lesion. Such observations indicate that meningeal cell contamination should be avoided when attempts are being made to repopulate glial-deficient lesions in the CNS by transplanting central glial cells, since their effect is to partition the glial environment.     

Active rehabilitation for chronic low back pain: Cognitive-behavioral, physical, or both? First direct post-treatment results from a randomized controlled trial [ISRCTN22714229]

Background  

The treatment of non-specific chronic low back pain is often based on three different models regarding the development and maintenance of pain and especially functional limitations: the deconditioning model, the cognitive behavioral model and the biopsychosocial model.