Differential Expression of Genes within the Cochlea as Defined by a Custom Mouse Inner Ear Microarray

Microarray analyses have contributed greatly to the rapid understanding of functional genomics through the identification of gene networks as well as gene discovery. To facilitate functional genomics of the inner ear, we have developed a mouse inner-ear-pertinent custom microarray chip (CMA-IE1). Nonredundant cDNA clones were obtained from two cDNA library resources: the RIKEN subtracted inner ear set and the NIH organ of Corti library. At least 2000 cDNAs unique to the inner ear were present on the chip. Comparisons were performed to examine the relative expression levels of these unique cDNAs within the organ of Corti, lateral wall, and spiral ganglion. Total RNA samples were obtained from the three cochlear-dissected fractions from adult CF-1 mice. The total RNA was linearly amplified, and a dendrimer-based system was utilized to enhance the hybridization signal. Differentially expressed genes were verified by comparison to known gene expression patterns in the cochlea or by correlation with genes and gene families deduced to be present in the three tissue types. Approximately 22–25% of the genes on the array had significant levels of expression. A number of differentially expressed genes were detected in each tissue fraction. These included genes with known functional roles, hypothetical genes, and various unknown or uncharacterized genes. Four of the differentially expressed genes found in the organ of Corti are linked to deafness loci. None of these are hypothetical or unknown genes.     

64排螺旋CT冠状动脉成像的前瞻性与回顾性心电门控技术的图像质量及辐射剂量的比较研究

目的 研究前瞻性心电门控触发(prospective ECG-triggering)与回顾性心电门控(retrosp-ective ECG gating)两种技术方法行冠状动脉CTA检查时,对冠状动脉图像质量及辐射剂量的比较.方法 33名疑似冠状动脉疾病的患者分两组进行对比研究.前瞻组16例为前瞻性心电门控成像,心率小于65次/min;回顾组17例为回顾性心电门控成像,心率小于75次/min.记录两组的辐射剂量并统计分析,同时进行图像质量评价.结果 两组图像质量比较,差异无统计学意义(P0.05).前瞻性心电门控冠状动脉CTA的平均DLP 234.4 mGy·cm,占回顾性心电门控冠状动脉CTA的平均DLP 974.4 mGy·cm的24.1%.前瞻性心电门控冠状动脉CTA的患者的平均有效剂量为3.2 mSy,回顾心电门控冠状动脉CTA患者的为13.6 mSv,降低76.47%.结论 64排螺旋CT在前瞻性心电门控冠状动脉CTA与回顾性心电门控冠状动脉CTA比较可以获得相似的图像质量,可大幅降低患者的有效剂量对于不能接受高辐射剂量且心率较低的受检人群具有重要的临床价值.     

Breast carcinoma: periodicity in presentation of metastatic tumour growth in the axilla

The clinical value of assessment of tumour load in the axilla in the treatment of breast cancer patients has stood the test of time. Much information is available on its extent and characteristic distribution but, in contrast, little is known of the biological factors that may control the timing of the metastatic phenomenon. There is recent circumstantial evidence that such factors may exist and this prompted the present detailed study of axillary metastases from a series of 437 consecutive cases of breast carcinoma. Evidence of such factors was found here also: the excess of micrometastases in cases coming to operation in the second half of the year was highly significant (P < 0.001) and is consistent with a synchronized start to the metastatic process. The total metastatic pattern in the material further indicated that the process may show periods of inactivity, i.e. periods when new colonies are not recruited. Mechanisms controlling this periodicity could theoretically be light-mediated, opening up new possibilities in the development of anti-metastatic treatment regimes.     

Erratum

Dynamic shimming has been implemented in three pulse sequences on a commercial GE Signa 1.5-T imaging system. Multi-slice field maps are acquired before the imaging sequence, and linear shim terms and center frequencies are calculated for each slice. During the imaging scan, the linear shim terms and center frequency are set before each pulse sequence repetition according to the current slice. Acquisition of multi-slice field maps and calculation of shim terms and center frequency for each slice are accomplished in a matter of seconds. Pulse sequences require only minimal modification to add dynamic shimming capability. Results are shown for a fat saturation spin-echo sequence, a single-shot echo-planar gradient-recalled echo sequence, and a spiral acquisition gradient-recalled echo sequence. In all cases, dynamic shimming with shim currents and center frequency optimized for each slice is shown to give better results than constant shim currents and a single center frequency optimized for the entire volume of interest.     

多层螺旋CT颈动脉成像:不同注射流率与成像方法的相关研究

目的 通过比较3种不同对比剂注射流率对多层螺旋CT颈动脉成像的影响以期获得合理扫描参数，资料与方法 随机选择无脑缺血症状和脑梗死患者及有症状者共45例，随机分成3ml/s,4ml/s,5ml/s3组，对比剂用量根据扫描时间作相应的改变，其他扫描参数不变，采用最大密度和容积重建2种后处理成像方法。根据90条颈动脉血管边缘的清晰度，颈动脉的分级情况，颈动脉与其邻近软组织之间的密度差，颈静脉和甲状腺的密度综合评分，由2位有经验的放射科医师用盲法评分，对比3种不同注射流率对成像的影响，所有统计工作由SPSS软件完成。结果 与3ml/s组相比，4ml/s组颈动脉强化峰值升高明显，使得颈动脉与邻近软组织间密度差异增大，3D图像信噪比提高。小血管显示的长度，血管边缘清晰度均有明显改善。5ml/s与4ml/s组之间的差异不明显。此外，5ml/s注射流率可带来扫描伪影。结论 随着注射流率的加快，颈动脉与邻近软组织密度差异变得愈明显，但注射流率超过4ml/s已无明显临床意义。     

螺旋CT多维重建成像在骨与关节病变诊治中的应用

目的　探讨螺旋CT多维重建成像在骨与关节病变诊治中的应用价值。方法　用螺旋CT对 1 0 4例骨与关节行容积扫描 ,包括骨折 57例 ;肿瘤 2 2例 ;结核及其他 2 5例。利用工作站对容积数据进行多维重建、表面遮盖法重建 (SSD)、多层面重建 (MPR)、多层面容积重建 (MPVR)、RaySun重建。结果　CT重建技术能显示骨与关节表面结构、内部细微结构 ,可以多角度、多平面观察骨与关节的密度、形态、大小变化 ,发现相邻肌肉、软组织改变及空间关系。结论　螺旋CT多维重建成像能提供非常有价值的空间关系信息 ,其表现接近病理解剖 ,临床应用价值大 ,有助于临床医生选择治疗方案和制定手术计划。     

Cochlear helix and duct length identification – Evaluation of different curve fitting techniques

Objective: Within the field of cochlear implantation (CIs), the role of utilizing patient-specific cochlear anatomy for choosing the optimal implant electrode is becoming increasingly important. Unfortunately, performing detailed anatomical measurements of a cochlea using clinical imaging data is rather time consuming and hence difficult to implement into the clinical routine. In order to accelerate clinical cochlear anatomy evaluations, previously developed mathematical models can be adjusted to the patient-specific anatomy by measuring just a few overall cochlear dimensions. However, the accuracy of model-based cochlear anatomy estimations is unclear, and incorrect evaluations may lead to false conclusions regarding the suitability of specific implant electrodes.

Methods: Based on 10 cochleae, an error evaluation of various commonly used curve fitting approaches for cochlear shape and duct length approximation was conducted. Spline tracings of the cochlear contours were used as reference values for the various approximations.

Results: Parameterized average cochlear helix models and two of five analytical approaches were found to be suitable for reconstructing the cochlear helical shape and estimating its length.

Discussion: Spline curve reconstructions are the most accurate and reliable method for assessing patient-specific cochlear geometry, especially in the case of anatomical irregularities. The most accurate results within the group of model-based evaluations still resulted in mean overall cochlear length deviations of approximately 5%.

Conclusion: Spline curve reconstructions appear to be the best option for anatomical diagnostics in clinical practice. Retrospective studies can be performed to further evaluate model-based evaluations.     

Virtual endoscopy of the nasal cavity in comparison with fiberoptic endoscopy

Purpose: To apply virtual-endoscopic mode to display the nasal cavity and to evaluate clinical application of virtual endoscopy in comparison with nasal fiberoptic endoscopy. Materials and methods: Eleven patients were examined by virtual endoscopy after axial spiral computed tomography (CT) scanning was performed. In addition, 9 out of these 11 patients underwent fiberoptic endoscopy. Spiral CT scanning was performed with 1-mm collimation, 0.5- to 1-mm increment, 25–250 mA s, and pitch 1–2. Virtual endoscopy was performed by Explorer software package. Results: Virtual endoscopy could clearly demonstrate anatomic structures in the nasal cavity, septal deviation, stenosis and obstruction of the middle meatus, turbinate hyperplasia, and pathological masses larger than 3 mm in diameter. However, “false adhesions” may appear in virtual endoscopy. The main limitation of virtual endoscopy was the inability to evaluate mucosa and its surface. Conclusion: Virtual endoscopy of the nasal cavity is a new and noninvasive method. It can demonstrate normal and pathological structures in the nasal cavity. Its ability to visualize is comparable with fiberoptic endoscopy except for evaluating mucosal surface and secretions. In the future, this method will probably be a basic instrument of computer-assisted surgery in the midfacial region. Received: 9 December 1999 / Accepted: 7 September 2000