A projection access order for speedy convergence of ART (algebraic reconstruction technique): a multilevel scheme for computed tomography

The practical performance of algebraic reconstruction techniques (ART) for computed tomography (CT) depends heavily on the order in which the projections are considered. Complete orthogonalization, notwithstanding its theoretical justification, is not feasible because the computational time is prohibitive. The authors report here a scheme that yields the most efficient reconstruction without orthogonalization: projections are organized and accessed in a nominally multilevel fashion. Each level makes the best use of the image information reconstructed in the preceding levels. If the number of projections is a power of two. Then the access orders are exactly that for the 1D FFT. The authors' scheme can be easily implemented. Using it, one iteration of ART yields a high-quality image. Experimental results of this algorithm are demonstrated and compared with the results from the conventional sequential method and also random ordering. Comparisons show that this scheme is superior. ART is better in image quality than the Fourier back-projection algorithm, at least for a smaller number of projections. Since the authors have made it much more efficient in computational speed, ART could now find widespread use in medical imaging.     

Microdissection and microcloning of chromosomal alterations in human breast cancer

Summary The recognition of recurring sites of chromosome changes in malignancies has greatly facilitated the identification of genes implicated in the pathogenesis of human cancers. Based especially upon recent studies [1–4], it appears increasingly likely that a subset of recurring chromosome alterations will be recognized in human breast cancer. Currently recognized chromosome changes characterizing breast carcinoma include the recognition of cytologic features of gene amplification (e.g. double minutes [dmins] and homogeneously staining regions [HSRs]) [5–8]. As these and other chromosome regions are implicated in recurring abnormalities in breast cancer, it will become increasingly important to have band-or region-specific genomic libraries and probes in order to facilitate high resolution physical mapping and ultimately to clone breast cancer related genes [9]. Toward this end an important recent development in physical mapping has been the establishment of chromosome microdissection as a rapid and reproducible approach to rapidly isolate and characterize chromosome region-specific DNA, greatly facilitating the initial steps in positional cloning of disease-related genes [10–13]. In this brief report, we will highlight the application of chromosome microdissection to the generation of region-specific probes for both fluorescent in situ hybridization (FISH) and the generation of genomic microclone libraries. Additionally, efforts using this methodology to generate a microclone library encompassing the early onset breast/ovarian cancer (BRCA1) gene will be presented.Presented by Jeffrey M. Trent at the 16th Annual San Antonio Breast Cancer Symposium, San Antonio TX, USA, November 4, 1993; Minisymposium on Molecular Genetics in Breast Cancer.     

高校离退休老人躯体健康与心理状况的相关性研究

目的：了解离退休老人躯体健康和心理状况的关系。方法：采用ＣＭＩ和ＳＣＬ－９０对２２５名高校离退休老人进行调查,分析两者的关系。结果：既往健康状况、神经系统疾病和躯体化成正相关;强迫与呼吸系统疾病成正相关,与心血管系统疾病成负相关;疲劳感和敌对成负相关,和睡眠饮食障碍成负相关。结论：维持老人心身健康,主要在于防治慢性疾病和神经系统疾病,以及对躯体化障碍和强迫症状的干预     

引导组织再生术屏障膜放置时间的研究

在 ３０ 只成年兔的下颌两切牙唇侧牙槽骨制备 １０ｍ ｍ ×５ｍ ｍ 的开窗骨缺损,其表面覆盖 Ｇｏｒｅ Ｔｅｘ 膜。该膜分别于术后 １、２、３、５ 周取出,以不放膜组为空白对照。所有动物５ 周处死,标本作组织学分析。结果表明,２ 周取膜组较空白对照组有更多的新骨形成,而 ３ 周或 ５ 周取膜组织的再生量无进一步增加。提示在引导兔开窗骨缺损的牙周再生中,屏障膜放置所需要的最适宜时间是 ２ 周。     

HPLC法测定蔓荆子黄素的含量

以蔓荆子黄素为指标,用反相 ＨＰＬＣ法测定了蔓荆子中的含量,实验采用 Ｃ_(１８)柱,以甲醇－０．４％磷酸溶液（６０： ４０）为流动相,检测波长 ２５８ｎｍ,用外标法测定,回收率为 ９８．１８％,ＲＳＤ１．４６％,线性范围 ０．１５～０．７５μｇ。本法快速简便,重现性好,为蔓荆子质量控制提供了可靠的依据。     

抗A1试剂血清的研制

目的 :ABO亚型在临床输血中经常造成错定血型及输血反应 ,因而研制抗A1试剂血清是解决ABO亚型鉴定的主要途径。方法 :采用血型血清学特异性抗原抗体吸收实验。结果 :经大量反复实验 ,研制出特异性强 ,效价符合要求的抗A1试剂血清。结论 :抗A1血清是鉴定A亚型的专用试剂血清 ,对临床鉴定ABO亚型及安全输血有实用意义。     

左室重量与左心功能不全相关性的研究

目的：研究可否用左室重量表达并判定左心功能不全的可能性。方法：将左心功能不全按NYHA标准分成4个级别,每级1组,并设正常对照组,用超声心动图测量同一个病人的左室射血分数（LVEF）和左室重量。用SAS统计软件做方差分析。结果：LVEF与左心功能不全高度负相关（R＝－0．77270）,左室重量与左心功能不全高度正相关（R＝0．73421）。LVEF、左室重量各级指标间差别显著（n＝153,F＝64．85,P＜0．01;n＝153,F＝53．39,P＜0．0001）。各级与对照组比统,LVEF指标从Ⅱ级开始方有显著差别（P＜0．05）;而左室重量指标从Ⅰ级开始就有显著差别（P＜0．05）。结论：LVEF与左室重量指标均与左心功能不全高度相关,但心功能Ⅰ级的病人,左室重量指标更为敏感。     

晶状体上皮细胞PAI—1蛋白酶mRNA的表达

研究从转录水平确定晶状体上皮细胞是否能够合成纤麦原激活物抑制物－１蛋白酶。方法体外培养的牛晶状体上皮细胞,当细胞生长融合后,抽提ＲＮＡ;采用Ｎｏｔｈｅｒｎｂｌｏｔ分析技术,对抽提得到的牛晶状体上皮细胞ＲＮＡ用特异的ｃＤＮＡ探针进行检测。结果在牛晶状体上皮细胞的基因转录产物中存在有ＰＡＩ－１ｍＲＮＡ的表达,所表达的ＰＡＩ－１ｍＲＮＡ碱基长度为２．３ｋｂ。结论牛晶状体上皮细胞能够分泌ＰＡＩ－１蛋白酶：     

睫状体冷冻术联合巩膜穿刺术治疗绝对期青光眼

目的评价睫状体冷冻术联合巩膜穿刺术在治疗绝对期青光眼中的应用。方法对绝对期青光眼４７眼施行睫状体冷冻术联合巩膜穿刺术,观察术后３ａ内眼压变化。结果全部病例术后高眼压症都获缓解,对术后早期眼压反弹,本术较单纯施行睫状体冷冻术者控制眼压疗效好（Ｐ＜０．０１）,且无副作用和并发症。结论睫状体冷冻术联合巩膜穿刺术是治疗绝对期青光眼更简便、安全、有效的手术选择。