Comparison of the Effects of Intravenously Bolus-administered Endothelin-1 and Infused Angiotensin II on the Subcutaneous Tumor Blood Flow in Anesthetized Rats

To evaluate the effects of endothelin-1 (ET-1) on tumor blood flow, the authors measured the mean arterial blood pressure (MABP) of enflurane-anesthetized male Donryu rats and the tissue blood flow of subcutaneously implanted tumor (Yoshida rat ascites hepatoma LY-80) by using a hydrogen clearance method. The tumor blood flow was evaluated in terms of the ratio to the maximum blood flow, which was defined as the largest flow in the same position during successive measurements. After bolus intravenous administration of ET-1 (1.0 nmol/kg), MABP reached approximately 140 mmHg (at 5 30 min), diminishing gradually to the baseline level over 2 h. The tumor blood flow increased from 36.7 ± 20.6 to 59.5 ± 30.2% (n = 32, P <0.001, at 2 min), returning to the baseline level at 10 min. On the other hand, at 2 min after the beginning of continuous intravenous infusion of [Asp¹, Ile⁵]-angiotensin II (AII; the dose was determined by a blood pressure control system for keeping MABP at approximately 150 mmHg, consequently 0.26 μg/kg/min on the average), the tumor blood flow increased from 42.3 ±21.6 to 76.4±22.6% (n = 32, P < 0.001), which was significantly larger than the flow after ET-1. The results indicate that hypertension induced by systemic ET-1 injection is less effective than hypertension induced by continuous systemic AII infusion in increasing tumor blood flow; AII is probably a suitable agent as a safe and effective enhancer of tumor blood flow. Moreover, ET-1 appears to constrict arterial vessels in the microcirculation time-dependently, while AII constricts probably only normal peripheral arterioles.     

Catheter-manometer system damped blood pressures detected by neural nets

Degraded catheter-manometer systems cause distortion of blood pressure waveforms, often leading to erroneously resonant or damped waveforms, requiring waveform quality control. We have tried multilayer perceptron back-propagation trained neural nets of varying architecture to detect damping on sets of normal and artificially damped brachial arterial pressure waves. A second-order digital simulation of a catheter-manometer system is used to cause waveform distortion. Each beat in the waveforms is represented by an 11 parameter input vector. From a group of normotensive or (borderline) hypertensive subjects, pressure waves are used to statistically test and train the neural nets. For each patient and category 5–10 waves are available. The best neural nets correctly classify about 75–85% of the individual beats as either adequate or damped. Using a single majority vote classification per subject per damped or adequate situation, the best neural nets correctly classify at least 16 of the 18 situations in nine test subjects (bionomial P=0.001). More importantly, these neural nets can always detect damping before clinically relevant parameters such as systolic pressure and computed stroke volume are reduced by more than 2%. Neural nets seem remarkably well adapted to solving such subtle problems as detecting a slight damping of arterial pressure waves before it affects waveforms to a clinically relevant degree.     

Percutaneous recanalization of arteries: Status and prospects of laser angioplasty with modified fibre tips

Percutaneous balloon dilatation of arterial stenoses is a firmly established non-surgical treatment of ischaemic disease. The number of percutaneous transluminal coronary angioplasties performed per year in the USA approaches the number of coronary artery bypass graft operations. A great number of novel percutaneous recanalization schemes address the major problems of balloon angioplasty: failure to cross the stenosis (occlusion), failure to dilate effectively (15–20%), acute complications (5%) and re-stenosis within six months (30–40%). Laser energy can effectively evaporate atheromatous plaque, but delivery by an unmodified bare fibre creates only a small channel and carries a high risk of vessel-wall perforation in the coronary arteries. It appears impossible to maintain an axial position in small, tortuous and moving arteries with multiple side-branches. Coronary lesions are anatomically and structurally heterogeneous. Reduction of the perforation risk is being approached by four strategies: (a) optimization of the power source; (b) enhancement of laser-light absorption by plaque relative to artery wall; (c) improvement of plaque recognition; and (d) modification of the delivery system, which is discussed in detail. Recanalization of occluded femoropopliteal arteries with the 2.0-mm metal laser probe has proved to be safe and effective in more than 100 patients. The 2.2-mm rounded sapphire contact probe has been used with success in the peripheral arteries of over 30 patients. The recanalization mechanism of both probes is not yet fully understood. Closed-chest attempts at recanalization of coronary arteries by the 1.7-mm metal laser probe have been reported in 13 patients, with success in the majority. There were no complications requiring emergency surgery. The possible occurrence of embolism or spasm in three cases warrants a cautious approach to application of the metal laser probe in the coronary catheterization room. The primary benefit of laser recanalization with modified fibre tips is the possible transformation of a candidate for surgery into a candidate for balloon angioplasty. It remains to be established whether prior laser debulking of the atheroma will reduce the incidence of acute complications of balloon dilatation and will reduce restenosis in the subsequent year. In the past two years an avalanche of laser and non-laser recanalization schemes have been developed. In peripheral arteries, early results of most methods have shown an acceptably low incidence of acute perforations or other complications. The human arterial wall can take a heavy beating, both mechanically and thermally. In the next decade, catheter intervention techniques will progressively contribute to the treatment of peripheral and coronary artery disease.     

Assessment of distributed arterial network models

The aim of this study is to evaluate the relative importance of elastic non-linearities, viscoelasticity and resistance vessel modelling on arterial pressure and flow wave contours computed with distributed arterial network models. The computational results of a non-linear (time-domain) and a linear (frequency-domain) mode were compared using the same geometrical configuration and identical upstream and downstream boundary conditions and mechanical properties. Pressures were computed at the ascending aorta, brachial and femoral artery. In spite of the identical problem definition, computational differences were found in input impedance modulus (max. 15–20%), systolic pressure (max. 5%) and pulse pressure (max. 10%). For the brachial artery, the ratio of pulse pressure to aortic pulse pressure was practically identical for both models (3%), whereas for the femoral artery higher values are found for the linear model (+10%). The aortic/brachial pressure transfer function indicates that pressure harmonic amplification is somewhat higher in the linear model for frequencies lower than 6 Hz while the opposite is true for higher frequencies. These computational disparities were attributed to conceptual model differences, such as the treatment of geometric tapering, rather than to elastic or convective non-linearities. Compared to the effect of viscoelasticity, the discrepancy between the linear and non-linear model is of the same importance. At peripheral locations, the correct representation of terminal impedance outweights the computational differences between the linear and non-linear models.     

Arterial occlusion in patients with peripheral vascular disease treated with platinum-based regimens for lung cancer

Background:?Patients with cancer may be hypercoagulable, and smoking can cause both lung cancer and peripheral vascular disease. Cisplatin-based chemotherapy has been reported to cause a variety of vascular side effects. Case reports:?Five patients with bronchogenic carcinoma and peripheral vascular disease developed acute arterial occlusion soon after receiving a combination of cisplatin or carboplatin plus etoposide. All these patients had risk factors for atherosclerosis and three of them had preexisting known peripheral vascular disease. Conclusions:?The occurrence of acute arterial occlusion soon after initiation of chemotherapy suggests that it might have been a complication of this therapy. Hence, caution should be exercised when using platinum-based (and other?) chemotherapy in patients with known moderate or severe peripheral vascular disease.     

原发性肝癌综合治疗282例分析

本文报告１９８０年６月至１９９４年１０月治疗中晚期原发性肝癌２８２例，男２３８例，女４４例，年龄１７～７６岁，结节型肝癌１３０例，巨块型肝癌９２例，弥漫型肝癌６０例，其中自发性破裂大出血２１例，全部病例经Ｂ超显像，ＣＴ扫描，肝动脉造影，ＡＦＰ测定及病理组织学检查确诊。外科手术治疗９４例，其中脉叶切除３０例，半年、１年、２年、３年、５年生存率为７９．９％，５６．０％。２２．７％１３．６．和１０．０％；行肝动脉血流阻断为主的外科综合治疗６０例，半年，１年、２年生存率为７８．３％，５２．４％，１３．８％；手术探查４例，存活期均少于４个月。对不能切除的中晚期肝癌行介入栓塞治疗１８８例，半年、１年、２年、３年生存率为７３．４％，３８．８％，１９．７％和６．７％。     

Crutch-induced axillary artery injury

Purpose To describe the spectrum of radiologic findings in crutch-induced axillary artery injury and the effects of its unique pathophysiology on diagnostic evaluation and treatment.Methods Three patients with axillary crutch-induced axillobrachial injury were studied angiographically and percutaneous intervention was performed in two cases.Results One patient required surgical bypass of a thrombosed axillary artery aneurysm. One patient responded to percutaneous transluminal angioplasty (PTA) of a focal axillary artery stenosis. One patient with an axillary artery aneurysm and distal thromboembolic disease was treated by both thrombolysis and surgical thromboembolectomy and later by PTA of an axillary artery intimal disruption.Conclusion Chronic axillary crutch use may be associated with axillary artery stenosis, aneurysm formation, and secondary axillobrachial thromboembolic disease. Mural injury can be successfully treated by PTA and thromboembolic disease by thrombolytic therapy. Early identification of the axillary artery lesion is critical for long-term therapeutic results.     

非转流经典原位肝移植术中血气和电解质的变化

目的 探讨非转流经典原位肝移植术中患者动脉血气、电解质的变化及其原因。方法80例行非转流经典原位肝移植患者，采用气管内插管静吸复合麻醉。除监测血流动力学外，同时于麻醉前、无肝前期、无肝期30min和60min、移植肝门静脉和腔静脉开放5min和30min、手术结束时监测动脉血气及电解质，其中70例采集门静脉开放后的肝静脉血进行测定。并对血流动力学和代谢紊乱进行纠正。结果手术期间循环系统变化明显，腔静脉阻断期间血压下降、心率增快，门静脉开放后低血压，57例患者需应用血管活性药物。动脉血pH于无肝期30min开始下降，至术终恢复；二氧化碳分压(OaCO2)于下腔静脉开放后5min平均升高约4～5mmHg(1mm Hg=0．133kPa)。剩余碱(BE)平均值于无肝期下降，开放后个体间差值明显加大，为-13～ 9；血钾开放后5min时个体间波动在2．6～6．1mmol／L；血钙于麻醉后至开放后30min均降低，术终有所恢复。血钠基本保持平稳。开放后肝静脉血严重高钾、高CO2，而钠、钙、pH和BE显著降低。结论 非转流原位肝移植无肝期前，经适当调控内环境保持相对较稳定，门静脉和下腔静脉开放后出现明显循环波动和内环境紊乱，显著低钙、高CO2，而血钾和酸碱平衡变化的个体差异极大。     

指端脉波的检测及其研究

本文报告了一种不失真且稳定地检测指端脉波形的新电路,提出了由脉波图直接测量心血管参数以及动脉血压的设想和方法,并通过一定样本量的实验进行了论证,获得了一些很有意义的结果。具有一定的临床应用和推广价值。     

Losartan, nonpeptide angiotensin II-type 1 (AT1) receptor antagonist, attenuates pressor and sympathoexcitatory responses evoked by angiotensin II andL-glutamate in rostral ventrolateral medulla

We investigated the effect of losartan, a nonpeptide angiotensin II (Ang II)-type 1 (AT₁) receptor antagonist, on the responses evoked by Ang II andL-glutamate (L-Glu) in the rostral ventrolateral medulla (RVLM). Adult spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats were anesthetized with halothane and artificially ventilated. Responses of mean arterial pressure (MAP), heart rate (HR) and splanchnic sympathetic nerve activity (SNA) to microinjection of Ang II (100 pmol) orL-Glu (2 nmol) into the RVLM were examined following microinjection of losartan (10 pmol–10 nmol). Ang II increased MAP (16 ± 1mmHg in SHR and16 ± 1mmHg in WKY) and SNA (9 ± 1%and10 ± 1%, respectively), which were significantly (P < 0.01) attenuated by pretreatment with losartan (100 pmol − 10 nmol) in both strains. In addition, the pressor and sympathoexcitatory responses evoked byL-Glu were attenuated by losartan in a dose-dependent manner. The increases of MAP evoked byL-Glu (53 ± 6mmHg in SHR and39 ± 3mmHg in WKY) were suppressed to 5 ± 3mmHg(P < 0.01) and 4 ± 2mmHg (P < 0.01), respectively, in the presence of 10 nmol of losartan. The increase of SNA was also markedly inhibited by higher doses of losartan. The cardiovascular responses evoked byL-Glu, however, were not attenuated by pretreatment with either 1 nmol of [Sar¹, Thr⁸]-Ang II or 10 nmol of potassium acetate, suggesting that the effect of losartan onL-Glu response may not be attributed to the blockade of Ang II receptor or to the high concentration of potassium. These results indicate that the AT₁ receptor is responsible, in part, for the vasomotor action of Ang II in the RVLM and losartan has an inhibitory effect on pressor and sympathoexcitatory responses evoked byL-Glu by mechanisms other than those mediated by Ang II receptors.