Altered establishment/clearance mechanisms during experimental micrometastasis with live and/or disabled bacterial lacZ-tagged tumor cells.

To study micrometastasis at its earliest stages, the bacterial lacZ marker gene was introduced into human EJ Ha-ras-transformed BALB/c 3T3 cells (LZEJ), followed by their intravenous injection into nude mice. Lung micrometastases were easily identified by blue staining of lacZ-tagged cells minutes/hours after injection, permitting effective evaluation of establishment/clearance mechanisms of LZEJ cells. Different treatments were used to disable LZEJ cells (fixation, irradiation, or mitomycin C) to determine modulation of these processes--although unable to divide, these cells stain for lacZ expression for days after treatment. Fixation-killed cells generated large microfoci (> 13-15 cells/focus) with well-rounded morphologies while live, irradiated, or mitomycin-treated cells generated smaller, irregularly shaped foci (3-7 cells/focus). Fixed-cell foci were cleared more slowly from lungs than the other three classes, even when prefiltered to remove large aggregates. All foci of disabled cells were eventually cleared while a basal level of live-cell foci persisted. Co-injection of fixed and live cells (or preinjection of fixed cells, followed by live cells) resulted in complete clearance of live-cell microfoci; in contrast, preinjection of live cells (then injection of fixed cells) led to survival of live-cell micrometastases. Therefore, altered deformability and/or cell surface interactions of tumor cells modulate the effectiveness of host-clearing mechanisms in the lung and in some situations these altered cells facilitate clearance of live tumor cells that are normally tumor-progressing.     

460例胃癌纤维胃镜活检标本的病理观察

本文分析了460例胃癌胃粘膜活检资料,结果:男:女为2.36:1:51～60岁年龄组发病率最岛(37.17％);发生部位以胃窦部最多见,占46.74％;组织学分类以低分化腺癌最多,占51 52％;在伴随病变中,畅化生的检出率为21.74％,胃腺囊为35％,胃粘膜上皮异型增生为32.61％。本组材料提示,不完全性大肠型肠化生、异型胃腺囊及胃粘膜中度以上异型增生与胃癌有密切关系。     

细胞凋亡抑制因子（Fas／APO-1）与抗β2-肾上腺素能受体自身抗体的关系

目的 检测并比较心肌梗死急性期不同时间点，β2自身抗体阳性组与阴性组，患者血清中Fas／APO-1水平差异，了解β2自身抗体对Fas／APO-1的影响。方法 41例急性心肌梗死患者，分别于发病24h、7天、2～4周时取血，采用ELISA的方法，检测血清中β2自身抗体的阳性率以及Fas／APO-1的水平；另外取34位性别、年龄匹配的健康人的血同法检测Fas／APO-1作为对照。结果心肌梗死急性期Fas／APO-1的水平均高于对照组（P〈0．05），以梗死后24hFas／APO-1的水平为最高；心肌梗死急性期不同时间点，β2自身抗体阳性组Fas／APO-1的水平均高于阴性组，但两组的结果差异无显著性（P〉0．05）。结论 血清Fas／APO-1水平可以在一定程度上反映心肌细胞凋亡的变化趋势，β2自身抗体对Fas／APO-1的确切影响，有待更大规模的实验来证实。     

缩窄性心包炎的外科治疗

报告12例缩窄性心包炎外科治疗的体会，本组病例的特点是病史长，入院前误诊率高（41.6%)，心增厚达0.5-2cm，龟壳样变。结果：12例手术资料随访1-6a，手术疗效满意，认为对诊断明确者应及早手术治疗，尽可能彻底剥脱缩窄的心包是手术疗效的关键。     

经尿道前列腺电切气化术治疗前列腺增生568例报告

目的 :进一步探讨前列腺增生 (BPH)的有效手术新方法。方法 :采用经尿道前列腺电切术和气化术治疗BPH患者 5 6 8例。结果 :疗效满意 ,术后 3～ 6个月随访 ,国际前列腺症状评分 (IPSS) 8.5± 1.5分 ;最大尿流率 (Q max) 2 0 .5± 4 .5ml s,剩余尿量 2 9.1± 14 .2ml,未出现严重并发症。结论 :将电切和气化相结合行经尿道前列腺切除术是一种安全性高、并发症少、疗效确切的新手术方法 ,具有操作易掌握、出血少、速度快、安全可靠等优点。     

State and output feedback design for robust tracking of linear systems with rate limited actuators

A design technique (Control of Uncertain Systems with Bounded Inputs, Tarbouriech S, Garcia G, (Eds), Lecture Notes in Control and Information Sciences, vol. 227 , Springer: Berlin, 1997; 173–186) recently proposed for stabilization of a linear system with rate‐limited actuators is utilized to design feedback laws that cause the system output to track a desired command signal. This design technique combines two design techniques recently developed for linear systems with position limited actuators, piecewise‐linear LQ control (Automatica, 1994; 30 : 403–416) and low‐and‐high gain feedback (IEEE Trans. Automat. Control, 1996; 41 : 368–378), and hence takes advantage of both design techniques, while avoiding their disadvantages. In the case that only the output is available for feedback, the performance of the state feedback law is preserved by the use of a fast observer. An open‐loop exponentially unstable fighter aircraft is used to demonstrate the effectiveness of the proposed control design method. Copyright © 2002 John Wiley & Sons, Ltd.