Perimetric variability: Importance of criterion level

Perimetry suffers from considerable variability of results. A new technique for estimating individual criterion levels in normal subjects exposes the important role of psychological variables. The analysis depends on features peculiar to acuity perimetry. It can be accommodated in the regular examination. The results can be used to compensate for practice effects in serial examinations and to tighten the range of normal limits. The reduction in variation between normal subjects amounted to 57 per cent.     

Comparing hand-held computers and paper diaries for haemophilia home therapy: a randomized trial

Treatment of severe haemophilia with factor concentrates is by self-infusion in the home. Adherence to record keeping on paper diaries is poor. A randomized-controlled trial compared adherence with record keeping of paper diaries with hand-held computers. Forty-one individuals with severe haemophilia, were randomized to hand-held computers (n = 22) or paper diaries (n = 19) and followed for 6 months. About 86.2% (679 of 788) of infusions by patients in the computer group were in compliance with the data submission schedule compared with only 48.3% (358 of 741) of infusions by patients using paper diaries (P < 0.0001). The time intervals between infusions and the receipt of data were shorter in the computer group (median 0.25 vs. 25 days respectively, P < 0.0001). Reminder phone calls by the clinic were made less frequently to users of hand-held computers than to users of paper diaries (median one vs. five times, P < 0.0001). Accuracy of data was similar for both methods. Compliance with hand-held computers was superior to paper diaries. The clinic received data from hand-held computers mostly on the same day, and nurses could thereby provide clinical advice more effectively. Although hand-held computers did not result in increased accuracy, errors could be detected and corrected more rapidly. Electronic data can more easily be verified, analysed and summarized than that from paper diaries.     

计算机X线摄影适宜照射线量的探讨

目的以噪声的频率特性评价计算机X线摄影系统(computed radiography, CR)的适宜曝光量.方法在相同摄影条件下获得中速 CaWO4屏-Fuji片组合照片和CR照片,以此为基础,改变mAs,获得不同照射剂量下的CR影像,经相同的后处理条件输出它们的CR照片.用显微密度计依次对这些照片进行扫描,每张获得10万个密度值,作为离散随机信号来处理,用快速傅立叶变换计算威纳频谱(Wiener spectrum, WS),测试CR照片噪声的WS与中速CaWO4屏-Fuji片组合的照片噪声WS值相等的曝光量值.结果 (1)在照射剂量均为5.61μGy、照片密度均为1.0的情况下,在空间频率(ω)=0.1 LP/mm处,CR系统的WS值为 23.1×10 -6 mm2,屏-片系统的为20.1×10 -6 mm2;在ω=0.5 LP/mm处,CR系统的WS值为 9.73×10 -6 mm2,屏-片系统的为8.41×10 -6 mm2 .(2)当ω=0.1 LP/mm时,照射剂量为5.61μGy的CR照片的WS值分别是照射剂量为1.40、2.80、8.76、13.67、21.11μGy CR片的0.53、0.75、1.14、1.44、1.80倍;当空间频率为0.5 LP/mm时,照射剂量为5.61μGy的CR片的WS值分别是照射剂量为1.40、2.80、8.76、13.67、21.11μGy CR片的0.40、0.58、1.26、1.47、2.16倍.(3)在ω=0.5 LP/mm时,与照射剂量为5.61μGy的屏-片组合有相当的噪声水平的CR照片照射剂量大致为7.70 μGy左右.结论相同摄影条件下CR照片的噪声要比中速 CaWO4屏-Fuji片组合的大;随着照射量的增加CR系统总WS将减小,噪声下降;如想获得和屏-片相同噪声的影像,应适当增大CR系统的照射量.     

兔视网膜方向选择性神经节细胞树突的独特分枝模式及其生理意义

本实验研究了兔视网膜中的方向选择性神经节细胞 (direction selective retinal ganglion cells,DS cells)树突野的分枝模式。测量了视网膜中方向选择性神经节细胞和作为经典分枝模式神经元代表的α神经节细胞的树突直径。发现 ,方向选择性神经节细胞的树突在分枝后直径达到 0 .5 μm,进一步分枝树突直径仍保持在 0 .5 μm左右 ,这样 ,在方向选择性神经节细胞树突野中大多数树突直径在 0 .5μm左右。而作为经典分枝模式神经元代表的α神经元的树突每次分枝后都逐级变细 ,最终直径达到 0 .5μm左右 ,这样 ,α神经节细胞的树突直径大部分都大于 0 .5μm。我们应用程序“NEU RON”对在两种神经元模型中 ,抑制点落于兴奋点与胞体之间 (proximal)和抑制点不落于兴奋点与胞体之间 (distal)这两种情况进行模拟。我们发现 ,当抑制点不落于兴奋点与胞体之间时 ,在方向选择性神经节细胞的树突分枝模型中 ,抑制效果更强。那么 ,将使得方向选择性神经节细胞对抑制点落于兴奋点和胞体之间的要求变得不是那么迫切。所以 ,方向选择性神经节细胞的这种独特分枝模式 ,也许可以避免或至少减轻其在发育中可能会产生的连线的复杂性。并且 ,我们对得出的结论进行了电路分析 ,对方向选择性神经节细胞这种独特的分枝模式具有的?     

SARS与细菌性典型肺炎的胸部CT特征对比分析

目的：探讨重症急性呼吸综合征(SARS)与细菌性典型肺炎胸部CT特征的异同．方法：回顾性分析28例SARS胸部CT表现与细菌性典型肺炎做对比结果：本组28例患者肺部病变初期多为单发病灶，在右侧外带胸膜下常见。片状磨玻璃样密度病变影存在于各期，而细菌性典型肺炎未见、发病初期和进展期肺容积变小?而细菌性典型肺炎多无此特点。进展期大多数发展为双肺由下至上痛变、恢复期病变由最晚受侵部位消退，遗留纤维化多为最早发生病变部位?而典型肺炎多从近肺门侧开始吸收，进展期局限的肺段、肺叶发展至多个肺叶、肺段，进展较迅速。而细菌性典型肺炎多为单独的肺叶、肺段．恢复期由弥漫性多发病变转变为局限病变，部分病人有肺部纤维化发生，而细菌性典型肺炎大多数吸收较完全，不遗留肺纤维化。结论：SARS所存在的急性间质性肺炎和急性肺炎可利用CT动态检查较准确地与细菌性典型肺炙加以区别。     

An imaging routine for assessing the efficacy of instruments used for scaling and root planning

Deposits of dental plaque or calculus are typically quantified using planimetric techniques. However, error is introduced into a quantitative analysis of plaque deposits using these methods, since they require a significant amount of human intervention. The purpose of this study is to describe and validate a computerized imaging routine which has the potential to objectively identify material on dental roots and measure the area covered by these deposits. Dentiform teeth with simulated plaque were videorecorded. A computer routine was developed based on a flood-fill algorithm which analyzed images of the dentiform teeth and determined the amount of simulated plaque on their root surfaces. Results showed that the dentiform teeth and their simulated plaque patterns are duplicated by the imaging routine in a rapid and reliable fashion. The system shows a high degree of accuracy with an average error factor of only 0.58%. As well, the system enables precise reproducibility with an average error factor of only 0.71%.     

150例颅面部外伤中眼部损伤的CT发现与临床表现的相关性研究

目的　探讨颅面部外伤中眼部损伤的部位和程度与CT扫描发现之间的关系。方法　回顾性分析 15 0例眼部损伤病人的临床表现和CT结果。结果　爆裂骨折多发生于内下壁 ,直接骨折以外壁多见 ,复合骨折常引起多眶壁骨折。合并颅骨骨折 92例。临床表现主要为眶周组织肿胀、眼球运动障碍和视力下降等。结论　CT扫描对眼部损伤病人选择治疗方案和评估预后有重要意义     

螺旋CT多功能重建在骨关节外伤中的应用

目的 探讨螺旋cT功能重建在骨与关节外伤中的应用，提高重建技术的使用能力和诊断水平。方法 对使用双层螺旋CT，SSD，MPR，MIP等多种方式重建检查的49例复杂的骨与关节外伤病例进行回顾性分析。结果 49例骨关节外伤重建成像，其中，颅底3例，颌面部7例，颈、胸、腰、骶椎共17例，肩胛骨3例，髋关节8例，膝关节11例。SSD在显示碎骨片明显移位的空间关系方面较MIP，MPR为佳，它可以直观地、立体地、清晰地、多角度显示骨关节损伤，而MIP在显示骨折细节方面较优，尤其在外伤中颅窝观察有关神经孔方面。结论 螺旋CT的SSD，MPR和MIP技术的综合应用，对复杂的骨折、关节损伤的显示效果良好，具有较高的临床应用价值。     

Using Computer Simulated Results of a Bulk Drug Substance Assay to Determine Acceptance Criteria for Method Validation

Purpose. To determine the statistical variability expected for a well designed HPLC assay of a bulk drug substance (BDS). The results are used to develop appropriate acceptance criteria for a method validation protocol as well as to evaluate the level of uncertainty expected for assay results using a variety of sampling/injection schemes. Methods. Computer simulation was used to generate a large quantity of data and the variability of the mock results was evaluated. Error propagation was also calculated, whenever possible, to confirm results obtained from the simulations. Results. Protocol acceptance criteria were developed that were consistent with the expected variability for data resulting from the execution of the validation protocol. In certain cases simulations provided the only avenue of obtaining results that could not otherwise be readily determined. Conclusions. Computer modeling can be used to obtain suitable acceptance criteria for validation results which are consistent with method variability. This is particularly significant in the case of linearity where it has been difficult to develop acceptance criteria based on anything other than analyst intuition and experience. Assay simulations clearly demonstrated that the variability expected for a typical BDS assay is large relative to the average specification range and therefore little insight about relative purity can be gained comparing individual passing assay results.     

Methods for analysis of a food frequency questionnaire

Fifty-five students and staff at Robert Gordon's Institute of Technology completed a food frequency questionnaire and then weighed their food for one week. Several methods of calculating nutrient intakes from the questionnaire are compared to results from the weighed inventory. Intakes of energy and several nutrients calculated using estimated typical portion weights were less than those derived from the weighed inventory. Food groups contributing to the apparent under-estimation have been identified. A further method of calculation involved derivation of a factor for each food group such that the frequency estimated from the questionnaire multiplied by the factor equalled the average weight of the foods in that group that had been eaten. Using these factors instead of the typical portion weights resulted in closer agreement to the weighed inventory method, but the difference ranged from positive for some groups to negative for others. Use of separate factors for each group of subjects reduced the range of differences to the weighed inventory method.