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。     

窒息鼠脑组织型纤溶酶原激活物活性变化与脑水肿的关系

目的：探讨窒息对鼠脑分泌组织型纤溶酶原激活物（TPA）的影响与脑水肿的关系。方法：通过“延迟剖宫产术”致胎鼠宫内窘迫，实验分空白对照组，窒息15min组，窒息30min组，窒息15min复氧30min组，窒息30min复氧30min五个实验组，每组各取8例测试脑组织TAP的活性及含水量，结果：窒息后鼠脑TPA活性与含水量均升高（P＜0．01），结论：窒息可致TAP活性增高，同时发生脑水肿，高活性的TPA可能是脑缺氧缺血致不可逆神经元损伤的一个重要媒介。     

Mechanisms of epileptogenicity in focal malformations caused by abnormal cortical development.

In this article, the authors review the cellular mechanisms of epileptogenicity in malformations caused by abnormalities of cortical development as related to neuronal excitation, reduced inhibition, disorganized synaptic connections, and glial function (or dysfunction).     

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.