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排序方式: 共有6014条查询结果,搜索用时 15 毫秒
51.
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Promoting clinically effective practice: general practitioners' awareness of sources of research evidence 总被引:3,自引:1,他引:2
Prescott K; Lloyd M; Douglas HR; Haines A; Humphrey C; Rosenthal J; Watt I 《Family practice》1997,14(4):320-323
BACKGROUND: Practitioners are being encouraged to base their clinical
practice on research evidence. In order to do this, they must be aware of
and use the sources of evidence. METHODS: A questionnaire survey was
undertaken to establish GPs' awareness of research evidence in their
clinical practice and, in fundholding practices, its influence on
purchasing plans. Questionnaires were sent to 360 lead fundholders in North
Thames Region and 440 of a random sample of the remaining general
practitioners in the region for comparison. RESULTS: Questionnaires were
returned by 62% of lead fundholders and 63% of GPs in the random sample.
There was limited use of the electronic sources of clinical effectiveness.
There was greater reported awareness of published sources of research
evidence and fundholding GPs were significantly more likely to have
referred to publications summarizing research evidence. CONCLUSIONS: GPs
seem to make more use of published clinical effectiveness sources than the
electronic databases. Consequently, they need educational and technical
support if they are to make full use of the available sources of research
evidence available in other media.
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We have videorecorded spontaneous cyclic contractions of capillary walls which often stopped the flow of blood cells, in spleens of rat and mouse. An inverted microscope and oblique lighting were key elements in obtaining images in which the boundaries of cells composing vessel walls were clearly distinguishable. Using slow motion replay, we measured the widths of endothelial cells (C), pericytes (P, when present) and capillary lumens (L; at the site of constriction; U; 15-20 micron upstream), throughout 11-12 min sequences containing many contraction/relaxation cycles. In roughly 50% of contractions L decreased to 0-1 micron, such luminal "closures" occurring within 2-12 sec and lasting for less than 1 sec to greater than 1 min. Intervals between contractions ranged from 12 sec to 3 min (average 1 min). Documentation of one such cycle by sequential photographs from the video monitor is presented, showing dramatic bulging of an endothelial cell into the lumen. Comparison of records of L and C versus time showed that almost invariably when L decreased C increased, and vice versa; highly significant correlations existed between C and L in every case (P less than 0.0005). Multiple linear regression analysis showed that changes in C were responsible for 18-77% of the total variance in L, whereas P contributed only 0-4%; changes in U, covariance between C, P, and U, and unexplained variance were responsible for 0-20, 11-30, and 11-53%, respectively, of the total variance in L. We conclude that these spontaneous capillary contractions were primarily due to endothelial contractility. 相似文献
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Microcystic spinal cord degeneration causing posttraumatic myelopathy. Report of two cases 总被引:1,自引:0,他引:1
Two cases of progressive myelopathy occurring years after incomplete cervical spinal cord injury are presented. In both patients, the clinical features, as well as the "bull's-eye" appearance of the delayed computerized tomography (CT) myelography study and the circumscribed low density of the magnetic resonance image, were consistent with posttraumatic syringomyelia, but surgical exploration including intra-operative spinal sonography failed to reveal a syrinx. Although arachnoiditis was present in both patients, the striking abnormality found at surgery was the softened appearance and the microcystic degeneration of the cord. The microcystic spinal cord degeneration found in these cases represents a previously undescribed cause of late deterioration after spinal cord injury that may mimic the clinical, CT-myelographic, and magnetic resonance features of posttraumatic syringomyelia. 相似文献
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Opioid peptides selective for mu- and delta-opiate receptors reduce calcium-dependent action potential duration by increasing potassium conductance 总被引:13,自引:0,他引:13
We suggest that both mu- and delta-opiate receptors on dorsal root ganglion neuron somata are coupled to voltage- and/or calcium-dependent potassium channels since opioid peptide decreases of calcium-dependent action potential duration were: (1) not associated with a change of resting membrane potential or conductance; (2) accompanied by an increase in action potential after-hyperpolarization, and (3) blocked by intracellular injection of the potassium channel blocker cesium [18]. In contrast, norepinephrine [4] and cadmium [9], which have been reported to act on voltage-dependent calcium rather than potassium channels, shortened action potential duration and decreased after-hyperpolarization amplitude, an action not blocked by intracellular iontophoresis of cesium. 相似文献