Pharmacokinetic interactions between midazolam and propofol: an infusion study

We have tested the hypothesis that the synergistic interactionwhich occurs when midazolam and propofol are combined for i.v. sedation is caused by an increase in the free plasma concentrationof one of the drugs. Six patients undergoing general anaesthesiareceived an infusion of propofol with the addition of an infusionof midazolam commenced 30 min later. Another six patients receivedan infusion of midazolam with the addition of an infusion ofpropofol 30 min later. All infusions were administered via pharmacokineticmodel-controlled syringe pumps programmed to maintain a constantplasma concentration. Venous blood samples were taken beforeand after introduction of the second infusion for later analysis.Free plasma concentration of midazolam increased from 2.0 (SD1.5) ng mt^–1 to 2.2 (1.9) ng ml^–1 after introductionof the propofol infusion (P = 0.32). Free propofol plasma concentrationwas unchanged at 18.5 (5.3) ng ml^–1 before and 18.7 (7.8)ng ml^–1 after introduction of the midazolam infusion (P= 0.94). It was concluded that the observed synergism with thiscombination cannot be explained solely by alteration in freeplasma concentration of either of these drugs when they areadministered together. (Br. J. Anaesth. 1994; 72: 62–65)     

Pattern of CBF in the rehabilitation of visuospatial neglect.

The CBF was assessed in seven patients before and after rehabilitation for visuospatial neglect. Two months of treatment produced an increased perfusion both in the right posterior and left anterior areas of the brain. However, only the left anterior CBF increase was correlated with the neglect disorders. The left anterior improvement in CBF was inversely correlated with right-left cerebellum asymmetry in pre- and post-treatment. The present data suggest the role of the frontal eye-fields in the mechanism of recovery of visual exploration in patients with severe neglect.     

Magnetic resonance and arthroscopy of the knee. A double-blind study in 40 patients]

To evaluate the capabilities of ultra-low-field MR for the high-resolution imaging of the knee with a short acquisition time, a prospective double-blind study was carried out on 40 consecutive patients with acute or chronic articular conditions who were examined with both MR imaging and arthroscopy. Three-dimensional gradient-echo MR sequences were employed which allow many thin high-resolution slices to be obtained in a relatively short time. To evaluate the results arthroscopy, performed the day after MR imaging, was considered the gold standard. MR imaging and arthroscopy were in agreement in 84.6% of meniscal tears with 91.6% sensitivity and 80% specificity, in 82% of anterior cruciate ligament lesions with 100% sensitivity and 80% specificity and in 81% of cartilage lesions with 100% sensitivity and 61% specificity. On the whole, MR imaging and arthroscopy were in agreement in 82.5% of cases with 97.2% sensitivity and 75.3% specificity. MR imaging gave more information about collateral ligament, muscle and bone involvement. These results confirm the capabilities of ultra-low-field MR imaging in the study of the knee: the technique allows diagnostic studies to be performed in a short time, at a low cost, and with similar results to those obtained with higher field strengths.     

C-fos immunoreactivity in the brain following unilateral electrical stimulation of the dorsal periaqueductal gray in freely moving rats.

C-fos immunoreactivity was used to reveal brain areas in which neurons were influenced by electrical stimulations applied to the dorsal periaqueductal gray. These stimulations were applied in freely moving rats so that the resulting behaviors could be observed. Shortly afterwards, the brains of the rats were processed for C-fos immunoreactivity. In order to determine the specificity of the brain areas thus labeled, control stimulations were applied to the ventral tegmental area of other rats. Immunoreactive cells were found surrounding the tip of the stimulation electrode within a radius of 0.5 mm. This labeled area extended further along the rostro-caudal axis than along the medio-lateral or dorso-ventral axis in the periaqueductal gray. Distally, clusters of labeled cells were found ipsilaterally in the caudal periaqueductal gray extending to the nucleus cuneiformis, and bilaterally in the locus coeruleus and supramamillary decussation. More widespread labeling was found in most hypothalamic subareas and in the lateral habenula. The labeled brain areas following ventral tegmental area stimulations were totally distinct, and comprised the medial forebrain bundle, the nucleus accumbens, the vertical limb of the diagonal band and the medial septum. The pattern of labeling produced by periaqueductal gray stimulations was therefore specific, and provided information about brain structures involved in the motivational and behavioral effects of such stimulations.     

运动员成功感量表的初步编制

目的 为运动员成功心理潜能的研究与训练提供有效的评价工具。方法根据心理问卷的编制原则，在调查研究的基础卜编制了运动员成功感量表，依照“设计测验题目、预备性测试与分析、正式测试”步骤进行研究．．结果通过因素分析，在53个测试条目中选取35个条目（因子负荷在0．4以上）作为正式量表内容条目，以特征值大于1为标准，抽取4个因子：成功感、自我满意感、积极情感体验和投入体验；量表四个因子维度与总分相关系数在0．578-0．784之间（P〈0．01）；运动员成功感量表与自我评价问卷及自尊量表存在着一定程度的相关性；量表α系数介于0．673-0．738之间（P〈0．01）；量表分半相关系数为0．858（P〈0．01）；重测相关系数0．730-0．894之间（P〈0．01）。结论量表比较符合设计构想，可以用来对运动员进行客观评价。