Variability of the steady-state visually evoked potential: Interindividual variance and intraindividual reproducibility of spatial frequency tuning

At low contrast levels there is good agreement between the psychophysical contrast sensitivity function and the tuning curve of the visually evoked potential (i.e., VEP amplitude vs spatial frequency). At high contrast, however, some researchers have found bimodal VEP tuning curves whereas others have not. We studied the VEP in 22 subjects in a short-term cross-sectional study and in 13 subjects in a longitudinal study over 8 sessions covering 28 days. Grating stimuli with 60% contrast were square-wave modulated in time (7.8 reversals/s) and space (0.06–16 cycles/degree). We found large interindividual variance in the shape of the tuning curves; about half of the subjects showed a unimodal shape, while the other half showed a bimodal one (with a notch between 1 and 2 cycles/degree). These features turned out to be stable in the longitudinal study, where variability could mainly be ascribed to a multiplicative influence common to all spatial frequencies. The marked interindividual differences in the shape of the tuning curve, which seem to be intraindividually stable, may explain previous discrepancies. It is not yet clear why the notch exists in about half of our subjects.     

星状神经节阻滞对家兔呼吸循环功能影响的初步观察

目的 :观察星状神经节阻滞对家兔呼吸循环功能的影响。方法 :选择健康成年家兔 5只 ,麻醉后暴露右侧星状神经节 ,用 1%利多卡因 1ml作局部浸润麻醉。观察阻滞前后呼吸频率、潮气量、动脉压、心率等的变化。结果 :与阻滞前相比 ,右侧星状神经节阻滞后呼吸频率及潮气量变化不显著 ;动脉压在阻滞后略有下降 ,但与阻滞前相比无显著差异 (P >0 .0 5 ) ;心率由阻滞前 141.8± 9.1次 /分下降到阻滞后 2min、5min、10min时的 12 9.8± 7.3次 /分、12 2 .4± 7.0次 /分、12 4.3± 7.4次 /分 ,且差异有显著性 (P <0 .0 5 )。结论 :右侧星状神经节阻滞对呼吸功能影响不明显 ,但对循环功能有一定的影响。     

6岁以下小儿头面部烧伤后体积变化的研究

为探讨小儿头面部烧伤后体积的变化,我们从1991年5月～1997年12月用陈壁教授提出热量计算小儿头面部体积的方法,对30例渡过休克期而生命体征平稳的6岁以下合并头面部重度烧伤的患儿在烧伤后48小时及5天～7天分别出量计算头面部体积,得出每1％头面部烧伤创面每kg体重烧伤后48小时内体积增加6.05±1.08cm3.明显高于目前习用输液公式伤后48小时每kg体重量1％烧伤面积2.7～3ml.为了准确计算此类病人休克期液体丢失量,建议分别计算头面部和其他部位创面伤后丢失量,从而指导临床治疗,提高救治水平.     

Do arachnoid cysts grow?

Summary The volumes of intracranial arachnoit cysts were measured in 136 CT scans of 86 patients. Absolute and relative cyst size was calculated. Left hemisphere and middle cranial fossa location prevailed. A slight negative correlation of relative cyst size with age (r=–0.21, NS) disappeared when analysis was restricted to the adult age group (20 years). After the sample was divided into two groups according to relative cyst size (cysts less than mean volume vs cysts greater than mean volume), small AC showed no correlation with age, while large AC correlated positively with age (r=0.79,P<0.05). A subgroup of large AC appears to expand with time, while the majority of small AC remain unchanged.     

免疫杀伤中LAK细胞的坏死和凋亡及黄芪多糖的影响

目的：进一步探讨ＬＡＫ细胞攻击Ｈｅｌａ细胞后的归宿及黄芪多糖（ＡＰＳ）的影响。方法：分别以ＩＬ－２和ＩＬ－２、ＡＰＳ激活的ＬＡＫ细胞与Ｈｅｌａ细胞共育，用电镜和电脑图像分析系统观察和测定ＬＡＫ细胞的存活、坏死、凋亡细胞及各期凋亡细胞不同时段的体密度。结果：对照组１６小时Ｈｅｌａ细胞大部分死亡，ＬＡＫ细胞本身死亡５７％。８、１６小时实验组ＬＡＫ细胞存活、坏死、凋亡细胞各自的体密度与对照组比均有差异（Ｐ＜０．０５）或明显差异（Ｐ＜０．０１），各期凋亡细胞的体密度也有差异或明显差异。结论：ＡＰＳ可降低ＬＡＫ细胞坏死和凋亡细胞的体密度，尤其是典型凋亡细胞的体密度，为抗肿瘤应用ＡＰＳ提高ＩＬ－２／ＬＡＫ细胞的活性提供实验根据。     

Right and left ventricular volume measurements in an animal heart model in vitro: first experiences with cardiac MRI at 1.0 T

The aim of this study was to determine the accuracy in quantifying right and left ventricular volumes using a 1.0-T system and commercially available, standard equipment. For exact comparison of MRI measurements and real volumes we used an animal heart model ex vivo. Eight pig hearts were explanted and prepared by removal of the atria. Aorta and pulmonary truncus were cannulated. Definable volumes were injected into the ventricles. Magnetic resonance imaging was performed at 1.0 T (Gyroscan T10 NT, Philips, Eindhoven, The Netherlands); sequence: fast field echo–echo planar (multishot EPI); body coil; MR software: Cardiac Application Package (Philips). Statistical analysis correlated the real volumes and MR measurements separately for both ventricles and two investigators (SAS, ANOVA). For both ventricles and both investigators the correlation between real volumes and MR measurements was greater than 0.99. There was no significant systematic false estimation for both ventricles. Magnetic resonance imaging at 1.0 T using standard hardware and software equipment enables the quantification of right and left ventricular volumes with high approximation to the real volumes in vitro. There is a clear restriction in translating these data into a clinical application because under experimental conditions no motion-induced artifacts existed. Received: 22 July 1999; Accepted: 27 August 1999     

多形性胶质母细胞瘤放疗临床靶区范围及治疗的讨论

间变性星形细胞瘤为WHO Ⅲ级，多形性胶质母细胞瘤为WHO Ⅳ级，美国NCCN2007指引中建议，对于高级别胶质瘤应最大范围切除肿瘤，术后病理为间变性星形细胞瘤者，应予放疗±同期化疗±辅助化疗；而若证实为多形性胶质母细胞瘤者，则应予放疗＋同期化疗＋辅助化疗。关于高级别脑胶质瘤靶区的勾画尚无定论。我们收治一例右侧额叶混合性胶质瘤（部分为间变性星形细胞瘤，部分为多形性胶质母细胞瘤），于外院行肿瘤全切术，术后经多学科讨论后认为应予放疗加替莫唑胺同期化疗及辅助化疗。本文就此病例的放疗靶区勾画及治疗进行讨论。     

新型3DSS-STD-Ⅱ结构光三维测量系统重建牙颌模型的可靠性对比研究

目的应用一种新型的三维测量系统3DSS- STD- Ⅱ对牙颌模型进行三维重建,评价该三维测量重建结果的可靠性,为口腔修复体计算机辅助设计奠定基础。方法利用新型结构光测量系统3DSS- STD- Ⅱ对标准下牙列模型从咬合面、右后侧牙列、前牙列区、左后侧牙列和正后方5个角度进行扫描,扫描后的结果经过数据合并、数据精简,利用反求软件Geomagic 6.0重建下颌牙列数字化模型。然后,用此软件自带测量工具测量切牙牙冠宽度、牙弓前段宽度、牙弓后段宽度、牙弓前段长度和牙弓后段长度相关指标,游标卡尺在石膏模型上测量各个相关指标,分析系统的可靠性、可重复性以及扫描精度。结果3DSS- STD- Ⅱ系统的可靠性与可重复性好,扫描精度结果显示与游标卡尺测量结果差异无统计学意义。结论新型结构光三维测量系统3DSS- STD- Ⅱ可靠性高、测量速度快,可以满足口腔模型三维数据快速采集和计算机辅助设计建模的需要。     

压力负荷联合超容量负荷致家兔心力衰竭模型的建立

目的 探讨压力负荷联合超容量负荷建立家兔心衰模型的可行性.方法 16只家兔随机分心衰组(8只)和假手术组(8只);先制备腹主动脉缩窄、1周后制备主动脉瓣关闭不全致压力负荷及超容量负荷,利用心导管术和心脏多谱勒观察手术前后家兔血流动力学及心脏结构和功能的变化.结果 (1)心衰组术后主动脉收缩压、脉压、左室舒张末压较术前明显增加(P<0.05);(2)心衰组术后左房内径、室间隔厚度、左室后壁厚度、左室收缩和舒张末内径均明显增加(P<0.05),射血分数及左室缩短率明显降低(P<0.05);(3)心衰组心脏及左室/体重比、肺脏/体重比明显高于假手术组(P<0.05).结论 压力负荷联合超容量负荷建立心衰模型方法可行,心衰形成时间短,成功率高,符合人类心衰病理生理过程.