When Is a Bispectral Index of 60 Too Low?: Rational Processed Electroencephalographic Targets Are Dependent on the Sedative-Opioid Ratio

Background: Opioids are commonly used in conjunction with sedative drugs to provide anesthesia. Previous studies have shown that opioids reduce the clinical requirements of sedatives needed to provide adequate anesthesia. Processed electroencephalographic parameters, such as the Bispectral Index (BIS; Aspect Medical Systems, Newton, MA) and Auditory Evoked Potential Index (AAI; Alaris Medical Systems, San Diego, CA), can be used intraoperatively to assess the depth of sedation. The aim of this study was to characterize how the addition of opioids sufficient to change the clinical level of sedation influenced the BIS and AAI.

Methods: Twenty-four adult volunteers received a target-controlled infusion of remifentanil (0-15 ng/ml) and inhaled sevoflurane (0-6 vol%) at various target concentration pairs. After reaching pseudo-steady state drug levels, the modified Observer's Assessment of Alertness/Sedation score, BIS, and AAI were measured at each target concentration pair. Response surface pharmacodynamic interaction models were built using the pooled data for each pharmacodynamic endpoint.

Results: Response surface models adequately characterized all pharmacodynamic endpoints. Despite the fact that sevoflurane-remifentanil interactions were strongly synergistic for clinical sedation, BIS and AAI were minimally affected by the addition of remifentanil to sevoflurane anesthetics.     

自锁式防旋自动滑动加压钉板的研制与生物力学研究

目的研制自锁式防旋自动滑动加压钉板（self—locking type pro-rotary auto-sliding＆compression nail plate，LPSC—NP）用于股骨颈骨折内固定，对其进行生物力学性能测试，为临床应用提供依据。方法采集18具新鲜成年股骨近端标本，制成股骨颈骨折，分别用LPSC—NP、3枚空心钉、双头中空加压螺纹钉、动力髋螺钉内固定，并进行生物力学测试，用SPSS统计软件对实验数据进行分析。结果LPSC—NP的承载能力和抗扭转强度、刚度均明显大于后三者。结论LPSC—NP固定股骨颈骨折牢固可靠，符合生物力学要求。该器械结构合理，简单适用，有一定的临床价值。     

Practice of orthokeratology by a group of contact lens practitioners in Hong Kong

Purpose: The aim of the study was to provide information about the characteristics of three main types of orthokeratology (ortho‐k) lenses used in Hong Kong and to report on their performance based on the clinical impressions of a group of ortho‐k practitioners. Method: Twelve ortho‐k practitioners were interviewed between 1 March and 30 June 2001. Results: Most ortho‐k lenses were ordered from three manufacturers: DreimLens, Fargo and Contex. The median maximum myopia reduction reported for DreimLens, Contex and Fargo lenses were 6.25 D, 6.00 D and 4.50 D respectively. The time to reduce myopia by up to 4.00 D could be up to three weeks for Contex and DreimLens and up to four weeks for Fargo. For reduction of myopia by up to 4.00 D, the treatment usually required only one or two lenses per eye for all three types of lenses. The incidence of lens binding and lens tightening after achieving the optimal reduction was reported to be higher with the DreimLens design. Good centration, less lens binding, relatively lower incidence of complications and lens tightening after achieving the optimal reduction were reported with the Fargo lenses. Conclusions: DreimLens tended to be more effective for myopia reduction. However, some practitioners were concerned with the aggressiveness of myopia reduction using this lens design and the higher potential for ocular complications. Selection of the lens design is dependent on various factors, in particular, practitioners need to be comfortable with the design they choose and to consider the needs of their patients and the final goal of the treatment.     

Henneguya shackletoni sp. nov. (Myxosporea, Bivalvulida, Myxobolidae) from the Falklands mullet, Eleginops maclovinus (Cuvier) (Teleostei, Eleginopidae) in the Falkland Islands

During a survey of the parasite fauna of the euryhaline notothenioid fish Eleginops maclovinus (Cuvier) caught in brackish water creeks in the Falkland Islands, small white cysts were observed in the mesenteries and on the surfaces of the visceral organs and heart. On dissection these proved to be plasmodia of a species of the myxosporean genus Henneguya. This is the first record of a member of this genus from a marine or euryhaline fish in the south-west Atlantic. A comparison of the spore of our species with other species in the genus convinced us that our species is new. This paper describes it as Henneguya shackletoni sp. nov. after the Shackleton Fund which funded the study.     

Poststroke DNA immunization against neurite growth inhibitors is beneficial to the recovery from local cerebral ischemia in rats

BACKGROUND： Inhibitory signals, i.e. neurite growth inhibitors （NGIs）, presenting on central nervous system （CNS） myelin have been shown to play a crucial role in inhibiting lesioned axonal sprouting and leading to less functional recovery. Vaccines targeting NGIs may provide multifactorial protection against brain insults by overcoming the inhibitory effects of these NGIs and boosting the body＇s immune repair mechanisms. OBJECTIVE： To evaluate the effect of poststroke DNA immunization against NGIs on the rehabilitation for sensorimotor function of rat models of local cerebral ischemia. DESIGN： Completely randomized grouping design, and controlled experiment. SETTING： Brain Injury Research Laboratory, Department of Neurosurgery, National Neuroscience Institute, Singapore. MATERIALS： Sixty adult male Sprague-Dawley rats ranging in age from 45 to 120 days and in weight from 180 to 250 grams were provided by Animal Center of Department of Anatomy, Faculty of Medicine, National University of Singapore. pcDNA3.1（＋）-neurite growth inhibitors （pcDNA-NGIs） a gift was provided by Dr. Xiao from Department of Clinical Research, Singapore General Hospital, Singapore. METHODS： The experiment was carried out at Brain Injury Research Laboratory, Department of Neurosurgery, National Neuroscience Institute, Singapore from August 2003 to April 2005. （1）The involved rats were randomized into 3 groups： pcDNA-NGIs group （group A）, pcDNA3.1 （＋） group （group B） and model group （group C）, with 20 rats in each group. Left focal cerebral ischemia （FCI） was permanently induced through middle cerebral artery occlusion （MCAO） with the assistance of an operating microscope. Successful MCAO was determined by a 20% decrease to baseline in the ipsilateral cerebral blood flow. 100 μg of pcDNA-NGIs eluted in phosphate-buffered saline （PBS） was intramuscularly injected into the tibial muscle once a week after MCAO for 6 weeks in group A. As control, pcDNA3.1 （＋） was also administrated in the same way in group B and nothing was administrated in group C. （2） The modified neurological severity score （mNSS）, a composite of motor, sensory, reflex and balance tests, was used to test the sensorimotor deficit. The mNSS was graded on a scale of 0 - 18, i.e. normal score was 0, maximal deficit score was 18, and 1 point was warded for the inability to perform the tasks or the lack of a tested reflex. （3） The newly generated axons of corticorubral projection were traced by stereotaxic guided injection of 100 g/L biotinylated dextran amine. Rats were sacrificed two weeks after tracing, and cryostat coronal sections of midbrains （30μm） were reacted to BDA according to the manufacturer＇s instruction by the free-floating method. Images were captured on a DM RXA2 LEICA Microscope with a Spot Digital Camera system （Germany）, and the numbers of labeled axons on the denervated side in four standard coronal sections including the red nucleus were manually quantified. MAIN OUTCOME MEASURES： （1） The number of newly generated axons of corticorubral projection. （2）The improvement in sensorimotor deficit. RESULTS： All the involved 60 rats entered the stage of final analysis. （1） The number of newly generated axons of corticorubral projection of rats： Only ipsilateral axons of CRP were noted with little evidence of fibers crossing to the contralateral red nucleus in rats of groups B and C. More BDA-positive fibers crossing the midline and terminating in the contralateral red nucleus in appropriate target areas mirroring the non-differentiated red nucleus were found in rats of group A. Quantitative analysis showed that BDA-labeled axons in the denervated side of rats in group A were more than those in group B （P 〈 0.05）. （2） Improvement in sensorimotor deficit of rats： At 2 weeks after immunization, significant improvement in sensorimotor deficit was found in rats of group A. There were significant differences of improvement in sensorimotor deficit of rats between group A and group B or group C at 12 and 14 weeks after immunization （P 〈 0.05）. CONCLUSION： （1） Poststroke DNA immunization against NGIs leads to increased sensorimotor recovery following FCI and compensatory newly growth of axons from corticorubral projection.