Local variations in the cerebral microcirculatory response to hypercapnia and haemorrhage

Summary This study evaluates local variations of the cerebral vasomotor responses to hypercapnia and haemorrhagic hypotension in a pig model. Four laser Doppler flow probes were used in each pig. There was considerable variation in laser Doppler signals between the four probes in baseline recordings. The increases in flow after CO₂ administration in 7 pigs had a mean coefficient of variation of 0.43 ± 0.31, and the flow changes after blood loss in another 7 pigs had a mean coefficient of variation of 0.45 ± 0.34. The range of flow changes within each animal was large; the probe with the highest CO₂ response showed on the average a 273% ± 157% larger CO₂ response than the probe with the lowest CO₂ response. Correspondingly, the probe with the best preserved blood flow after blood loss had on the average a flow value of 93% ± 12% of the baseline value, while the probe that changed most with haemorrhage had a flow value of 44% ± 24% of the baseline value. Single laser Doppler recordings have been used for the monitoring of cerebral blood flow in neurosurgical critical care, but our results suggest that a single laser Doppler flow probe is not an adequate method to monitor vasoreactivity in neurosurgical patients because flow signals from one probe may be unrepresentative for other sites in the brain.     

The estimation of the plasma free fraction of cyclosporine in rabbits and heart transplant patients: The application of a physiological model of renal clearance

We estimated the free fraction (f_u) of cyclosporine (CyA) in the plasma from concentrations of CyA in urine (C_u) and plasma (C_p), urine flow rate (UF), and glomerular filtration rate in rabbits and in heart transplant patients. Following intravenous administration of CyA (5–30 mg kg^?1) in ten NZW rabbits and oral administration of CyA (4.8–12.1 mg kg^?1) in nine heart transplant patients, CyA concentrations in urine and plasma were measured by HPLC. The ratios of C_u to C_p and UF data were fitted to a physiological model of renal clearance using NONMEM. The free fraction of cyclosporine in the rabbits and the heart transplant patients was 0.0122 and 0.14, respectively. Because of the relatively low permeability of CyA across the tubular epithelium, no apparent equilibrium between C_u and C_p at any urine flow rate was reached and, therefore, the C_u to C_p ratio will not be equal to f_u.     

应用流式细胞仪对肺癌细胞增殖活力的分析

本文应用流式细胞仪对35例肺癌、10例良性病变肺组织及10例正常肺组织的细胞增殖活力(S％)进行了分析,结果显示肺癌组织细胞增殖活力非常显著高于良性病变组,良性病变组细胞增殖活力亦非常显著高于正常组,提示检测细胞增殖活力对肺癌的诊断、筛选有一定意义。     

Development of an isolated, pulsatile blood-perfused rat lung model for evaluating the preserved lung functions

The purpose of this study was to develop an isolated, pulsatile blood-perfused rat lung model that allows us to evaluate the preserved lung functions. Lungs isolated from Sprague-Dawley rats, were perfused with venous whole blood by either a pulsatile or constant flow. The effuent was continuously deoxygenated with a 95% N₂/5% CO₂ gas mixture. Airway resistance, lung compliance, elastic work, flow resistive work, pulmonary vascular resistance, and blood gas analysis were assessed. Pressor responses toN ^G -monomethyl-l-arginine (l-NMMA) were compared between pulsatile and constant blood flow. At a flow of 0.1 ml/g body weight/min, pulsatile perfusion allowed for stable perfusion at least for 2h (mean 162.5±15.1 min) with stable aerodynamic and hemodynamic variables including blood gas tensions, whereas constant perfusion resulted in immediate lung failure. Whenl-NMMA was added to the perfusate, the mean pulmonary artery pressure did not show any change in the constant flow (6.0±2.6% increase), but did show a significant increase in the pulsatile flow (45±11% increase). Pulsatile blood flow reduced the pulmonary vascular resistance relative to the constant flow and allowed for a 2-h perfusion period to evaluate the lung function. The vasorelaxant mechanism in the pulsatile perfusion is related in part to the endothelial-dependent relaxation observed in the nitric oxide pathway. Presented in part at the 79th, Annual Clinical Congress of the American College of Surgeons (ACS) held in San Francisco, CA USA, 1993.     

The anterior inferior cerebellar arterial network supplying the rat cochlea and its role in autoregulation of cochlear blood flow

Summary The sensitivity of the cochlea is dependent upon maintenance of a delicate homeostatic environment. One mechanism which participates in providing this environment is the autoregulation of cochlear blood flow. This autoregulation is ensured through the interaction of sympathetic, peptidergic and hemodynamic mechanisms. The current study demonstrates an adaptation that also participates in cochlear blood flow autoregulation. Specifically, an anterior inferior cerebellar arterial network is described and the relative contributions of each of its vessels to total cochlear blood flow is measured using laser Doppler flowmetry. The results show that each collateral vessel contributes to the blood supply of the cochlea and that reperfusion is accompanied by hyperemia. These findings suggest an adaptation that provides stable blood flow through redundancy and compensatory potential. Additionally, these observations have implications for experimental models of ischemia.     

A case of multiple leiomyomatous lesions of the lung: An analysis of flowcytometry and hormone receptors

A 36 year old woman was admitted to our department because of a chest X-ray which showed multiple developing shadows. She underwent bilateral exploratory thoracotomies and a total 5 tumors were resected and pathologically diagnosed as benign metastasizing leiomyoma, the largest of which was positive for the progesterone receptor and negative for the estrogen receptor. A histogram of this tumor using a flow cytometer showed a diploid pattern and 4.6 percent of the S phase which was not more than that of a leiomyoma of the uterus from another patient. Two months later, she underwent a hysterectomy and bilateral salpingo-oophorectomy for treatment of the positive progesterone receptor in the pulmonary lesions. The resected uterine myoma and normal myometrium showed positive estrogen and progesterone receptors. For the subsequent 28 months she has been free of any further symptoms. Benign metastasizing leiomyoma of the uterus is a rare disease and very interesting because of its histological benignity and hormonal dependency. However, according to the literature, it is often confused in entity due to the fact that normal lung tissue also possesses hormone receptors. Considering our data on hormone receptors, it is rational to think that multiple leiomyomatous lesions in the lung should only be diagnosed as benign metastasizing leiomyomas when they possess positive estrogen and progesterone receptors.     

缺血再灌流肾组织内皮素—1动态变化的实验研究

在大鼠肾缺血６０分钟再灌注的模型上观察不同时相肾静脉血、肾皮质、外髓和内髓的内皮素１（ＥＴ１）浓度变化，肾组织ＥＴ１光镜和电镜免疫组织化学变化。结果发现：缺血再灌流肾组织ＥＴ１基因表达及分泌明显增强，主要分布在血管内皮细胞及平滑肌细胞、系膜细胞、肾小管上皮细胞。其分布特点与细胞类型和活性有关。本实验结果提示了缺血再灌注肾内ＥＴ１的变化规律。     

瘤体内DNA倍体异质性与食管鳞状细胞癌病理特性的关系

目的探讨食管鳞状细胞癌瘤体内ＤＮＡ倍体异质性及其与肿瘤病理学特性的关系。方法采用多点取材方法，应用流式细胞术对８０例中晚期食管鳞癌标本的ＤＮＡ倍体类型进行分析。如果一个标本中的３个样品中的倍体类型不一致，即判定为倍体异质性肿瘤（ＰＨＴ），其余为非倍体异质性肿瘤（Ｎ－ＰＨＴ）。然后用统计学方法分析ＤＮＡ倍体异质性与肿瘤病理学特性的关系。结果８０例中，共检出异倍体肿瘤７１例（８８．８％），ＤＮＡ指数范围为０．７７～１．７４。倍体异质性肿瘤的检出率为４７．５％（３８／８０）。倍体异质性与肿瘤的侵润程度，淋巴结转移及患者预后有关（Ｐ＜０．０５～０．０２５），而与组织分级和瘤体大小无关（Ｐ＞０．０５）。结论ＤＮＡ倍体异质性是一种重要的肿瘤生物学现象。深入研究它将对判断肿瘤的病理特性、患者预后及协助组织学分级具有重要的价值。     

Geometric Resistance and Microvascular Network Architecture of Human Colorectal Carcinoma

Objective : To measure the geometric resistance to blood flow in human colorectal carcinoma. Although tumor blood flow is of central importance in both the detection and the treatment of cancer, the determinants of blood flow through the neoplastic circulation are poorly understood. Methods : Human colorectal carcinomas (tissue weight = 272 g ± 43 g (SD), n = 6) were perfused ex vivo with a buffered physiological salt solution of known viscosity at flow rates ranging from 2.5 to 40 ml/min and perfusion pressures from 8 to 100 mm Hg. The geometric resistance was determined from the slope of the pressure-flow curve. For examination of the principal determinant of geometric resistance, the vascular architecture, one of the tumors was perfused with Batson's No. 17 polymer and macerated in KOH to produce a positive vascular cast that was used for measurement of vascular branching patterns and dimensions. Results : The pressure-flow relationship was linear at perfusion pressures above 40 mm Hg, and the geometric resistance, z₀, was constant at approximately 6.5 ± 10⁹g/cm³. Below 40 mm Hg, z₀ increased rapidly. The architecture of the arteriolar and capillary networks of human colorectal carcinoma is similar to those of experimental rodent tumors. Capillaries in planar and nonplanar mesh-works had mean segment diameters of 11 ± 2 and 9.6 ± 2 μm, lengths of 46 ± 24 and 107 ± 40 μm, and intercapillary distances of 46 ± 13 and 74 ± 24 μm, respectively. Conclusions : The geometric flow resistance in neoplastic tissue is 1–2 orders of magnitude higher than that observed in normal tissues. A decrease in functional vascular cross-sectional area may explain the additional increase in resistance at small perfusion pressures. The observed flow resistance may be due to the specialized arteriolar and capillary network architecture, pressures exerted by proliferating cancer cells, and/or coupling between vascular and extravascular flow. These observations demonstrate that tumor vascularity alone may not be indicative of flow resistance or tumor susceptibility to blood-borne therapeutic agents.     

大鼠肝抑素样提取物的生物效应初探

从大鼠肝分离出小分子蛋白质,注入肝大部切除的大鼠体内。术后24h制备肝细胞悬液及骨髓细胞悬液,用流式细胞计测定细胞DNA含量。结果:①实验组大鼠每克体重注入肝提取物10～300μg,一致呈现4n肝细胞DNA复制受阻于G_1期,各类肝细胞数与正常大鼠的相似;②对照组大鼠,4n肝细胞由正常的68.1％降至30.9％,8n肝细胞由6.3％骤增至25.3％,并出现16.8％的4n～8n间8期肝细胞;③两组大鼠的骨髓细胞DNA含量均无变化。表明肝提取物中含有肝抑素样物质,它特异性地使再生肝的4n肝细胞增殖周期阻滞于G_1期及S早期。