A porcine model for sequential assessments of cerebral haemodynamics and metabolism

We present a physiologically stable porcine model designed for sequential assessments of pharmacological effects on mean hemispheric cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO2) at sustained normocapnia. The dynamic influence of continuously administered fentanyl (0.040 mg.kg-1.h-1 i.v.), nitrous oxide (70%) and pancuronium (0.30 mg.kg-1.h-1 i.v.) on these variables was studied in eight normoventilated pigs. CBF was reliably assessable at 10-min intervals by clearance of intra-arterially injected 133Xe, monitored by an extracranial scintillation detector. CMRO2 was calculated from CBF and the simultaneously measured cerebral arteriovenous difference in blood oxygen content. The intracerebral distribution of a contrast medium injected into the external and internal carotid arteries was studied by angiography, and the cerebral venous outflow was investigated by measurements of the distribution of an intra-arterially administered non-diffusible tracer, [99mTc]pertechnetate, to the internal and external jugular veins. After a 3-h equilibration period, CBF and CMRO2 were determined on six occasions over a study period lasting 1 h 40 min. The mean ranges of these variables were 56-60 and 1.9-2.0 ml.100 g-1.min-1, respectively. We conclude that the model enables repeated assessments of CBF and CMRO2 under stable physiological background conditions and thus valid cerebral pharmacodynamic investigations of drugs given for anaesthesia.     

Magnetic resonance imaging and single-photon emission computed tomography changes in hypoglycemia-induced chorea.

We present two case studies, one of generalized chorea and one of hemichorea, both after severe hypoglycemia episodes. Both cases showed hyperperfusion in their SPECT scans. The MRI and SPECT findings serve as clues regarding the role of basal ganglion dysfunction associated with chorea.     

MRI在子宫肌瘤与子宫腺肌病鉴别诊断中的价值

目的 分析子宫肌瘤与子宫腺肌病的MRI表现特点，评价MRI在两病鉴别诊断中的价值。方法 回顾性分析66例经手术病理证实的子宫平滑肌瘤和子宫腺肌症患者MRI资料，仔细观察两病在T1W、T2W、STIR及增强后T1W像上的表现。结果 MRI对两病诊断的敏感性为100％，诊断符合率为91．7％。两种病变的T1WI信号、边界、T2WI上病灶周围的改变、病侧子宫内膜以及临近结合带的改变方面具有较大差异；而在子宫形态、T2WI信号特点及增强特点上并没有明显差别；T2WI及STIR图像对病灶的显示最清晰。结论 子宫肌瘤和子宫腺肌病由于病理基础不同，MRI表现也各有不同；选择合适的MRI检查序列与方法对两病鉴别诊断具有重要的价值。     

The effect of the synthetic neuroprotective dipeptide noopept on glutamate release from rat brain cortex slices

The level of spontaneous and K⁺-stimulated release of endogenous glutamate was studied in experiments on slices of brain cortex of Wistar rats. Pronounced spontaneous release of the neuromediator and its increase under conditions of stimulation were registered by high-performance liquid chromatography with electrochemical detection. The effect of the nootropic and neuroprotective dipeptide Noopept (GVS-111) on release of glutamate was investigated. The peptide in concentrations of 10^?5 and 10^?6 M caused a statistically significant decrease in spontaneous and K⁺-stimulated glutamate release. This effect could be the basis of the neuroprotective action of the peptide, suggesting that further studies of Noopept as neuroprotector are very promising.     

主动吸入药物烟对大鼠一氧化氮的影响

目的　探讨主动吸入药物烟对大鼠NO的影响。方法　制备大鼠主动吸烟模型 ,采用硝酸还原酶法测定各组大鼠血清、肺、心肌及脑组织的NO含量。结果　非药物烟组大鼠血清、肺、心肌及脑组织中NO含量明显低于非给烟对照组 ,药物烟高、中剂量组NO含量明显高于非药物烟组 ,接近非给烟对照组。结论　吸烟对大鼠血液、肺、心肌及脑组织有不同程度的损伤作用 ,使NO含量降低 ;药物烟具有一定的保护和防止NO含量降低的作用。     

亚低温在治疗急性颅脑创伤中的疗效和争议

二十世纪90年代初,国内外对亚低温脑保护的作用有了新认识。动物实验研究发现亚低温对实验性颅脑外伤具有显著的治疗保护作用。大多数前瞻性临床应用研究发现30～33℃亚低温能显著降低重型颅脑伤患者的死残率。但美国Clifton教授牵头的9个医学中心合作研究发现亚低温治疗组与对照组无统计学差异.仅能显著提高GCS 6～8分、年龄<45岁、伤后6h内达到亚低温水平的病人的治疗效果。最近一项欧州5家医院多中心前瞻性随机临床研究结果令人兴奋,他们研究证明亚低温对心跳骤停脑缺血缺氧病人有显著治疗保护作用。目前国内外有关亚低温治疗的争议焦点是亚低温治疗的指征、时间窗和时程。     

Neurobehavioral effects among subjects exposed to high static and gradient magnetic fields from a 1.5 Tesla magnetic resonance imaging system--a case-crossover pilot study.

The interactive use of magnetic resonance imaging (MRI) techniques is increasing in operating theaters. A study was performed on 17 male company volunteers to assess the neurobehavioral effects of exposure to magnetic fields from a 1.5 Tesla MRI system. The subjects' neurobehavioral performances on a neurobehavioral test battery were compared in four 1-hr sessions with and without exposure to magnetic fields, and with and without additional movements. Adverse effects were found for hand coordination (-4%, P < 0.05; Pursuit Aiming II) and near visual contrast sensitivity (-16% and -15%, P < 0.10; Vistech 6000). The results from the remaining tests were inconclusive due to a strong learning effect. No additional effect from gradient fields was detected. The results indicate that working near a 1.5 Tesla MRI system may lead to neurobehavioral effects. Further research is recommended, especially in members of operating teams using interactive MRI systems.     

神经导航辅助显微手术治疗脑功能区肿瘤

目的探讨神经导航系统辅助下脑重要功能区肿瘤显微手术的治疗效果和应用价值。方法1999年12月～2002年6月应用StealthStation神经导航系统辅助切除邻近脑重要功能区肿瘤10例,对神经导航系统术中应用的优越性、精确性等进行分析。结果本组平均注册误差为(2.8±0.9)mm,肿瘤和重要解剖功能结构定位准确,肿瘤全切除率77.8%。术后神经功能未受明显影响,无手术并发症及死亡。结论神经导航系统对于切除邻近脑重要功能区肿瘤具有定位准确,动态示踪和实时导航,侵袭性小,安全、可靠等特点,有助于提高肿瘤全切率及降低手术并发症。     

1.5T超导磁共振制冷系统的工作原理及日常维护

介绍GE 1.5T超导磁共振制冷系统的组成和工作原理,讨论日常维护的要点及其必要性。     

Identification of the C-terminal flanking peptide of preprocholecystokinin in rat brain by a novel radioimmunoassay

The C-terminal flanking peptide of preprocholecystokinin (preproCCK) has been identified in extracts of rat brain using a novel radioimmunoassay. There is a single form of immunoreactive material on gel filtration, ion exchange and reversed-phase HPLC. The C-terminal preproCCK immunoreactivity had a similar pattern of distribution to CCK8 in different regions of rat brain. This assay should help in studies of neuronal CCK biosynthesis.