动脉分支处的红细胞流变学研究与小动脉端侧吻合

为了探讨动脉分支处及小动脉端侧吻合处的血液流动方式，采用微循环电视显微镜成像技术，活体观察大鼠肠系膜微动脉分支区域血液流动方式和红细胞流变行为，研究动脉血流方向的改变对血流方式的影响。实验中观察到，在形态各异的大鼠肠系膜微动脉分支区域血液流态为稳定层流；红细胞通过不规则变形能很好地适应血管腔不同的几何形态，以保持血液流态的稳定。结果表明，微小动脉血流方向的改变未能在分支区域导致湍流发生，小动脉端侧吻合只是人为增加了侧支循环，同样不会导致血流紊乱和增加血栓形成的危险     

正常新生儿脐血血流变学的研究

本文总结报道了我院于1992-1993年对35例正常新生儿脐血进行血液流变学检测,结果提示正常新生儿早期全血粘度、血浆粘度、血小板聚集率,均较正常成人对照组显著增高;而红细胞沉降率显著降低.证明新生儿血液里高粘滞状态,这是新生儿疾病如新生儿硬肿症、肺出血、DIC等的病理生理基础,也为这些新生儿疾病的诊断和治疗提供了理论依据.     

肺炎患儿白细胞变形能力和粘附功能的变化及临床意义

肺炎患儿白细胞变形能力和粘附功能的变化及临床意义林荣军１刘成玉２潘玉娟３徐丽园研究表明，白细胞与急性肺组织损伤有密切关系［１］，白细胞在肺内聚集是产生急性肺损伤的重要环节，而细胞粘附分子（ｃＡｍｓ）介导的各种白细胞的粘附，特别是中性粒细胞粘附和跨膜转...     

The rheological characteristics of nasal mucus in patients with rhinitis

In this paper we have analyzed the physical properties of nasal mucus from 120 outpatients with rhinitis. We focused on the most relevant rheological features: viscosity, elasticity, adhesiveness, as well as ability to be spun (spinability) or poured (pourability). A double-capillary type viscometer was used to measure viscosity and elasticity and the platinum ring method to measure adhesiveness. Spinability was measured with an automatic apparatus (Filancemetre Sefam) and pourability was determined by describing flow under gravity. Efficacy of nasal clearance was analyzed by measuring mucociliary transport time with an inert tracer using vegetal charcoal powder. Results showed that impaired nasal mucosal function in patients with rhinitis could be determined by studying rheological features in addition to measuring mucociliary activity. Information provided proved invaluable when considering possible treatment with agents affecting kinesis of nasal mucus.     

The Rheology of Liquids: A Comparison of Clinicians’ Subjective Impressions and Objective Measurement

Texture-modified diets are commonly prescribed for patients with dysphagia; it is therefore important to demonstrate that clinicians form accurate impressions of the rheological (flow) properties of the items that they recommend for their clients. We explored the correlation between objective rheological measurement and clinicians subjective impressions of liquid consistency, rated on the bases of product labeling and sampling. Ten liquids, ranging from thin through nectar-thick and honey-thick to spoon-thick consistencies, were selected for study. Rheological analysis was conducted using a Carri-Med CSL Controlled Stress Rheometer. Fifty speech-language pathologists ranked the liquids in order of perceived viscosity, based on their interpretation of the product packaging and label. Product nomenclature proved insufficient to accurately represent the consistency class to which each liquid belonged. A second group of 16 speech-language pathologists rated the perceived relative viscosity and density of nectar-thick and honey-thick juice items in blinded two-point discrimination tests of stirring-resistance, oral manipulation, and vessel weight. Physical sampling of these two products enabled clinicians to reliably perceive relative viscosity and density differences between the nectar- and honey-thick items.     

Fluid trapping of erythrocytes under hypoosmolar conditions

Summary ¹²⁵I albumin was used to assess the amount of trapped fluid after microhematocrit centrifugation of erythrocytes suspended in buffers of different osmolality. Surprisingly the total amount of trapped fluid per volume unit of packed erythrocytes decreased with decreasing osmolality of the suspending buffer despite erythrocyte swelling. However, if the contribution of the individual erythrocyte to the trapped fluid was calculated, the trapped fluid per erythrocyte did not change between 311 mosm/kg and 256 mosm/kg. For osmolalities below 256 mosm/kg a significant increase of trapped fluid was obtained. It is concluded that the packing ability of erythrocytes is not impaired in suspending fluid of moderate to severe infraphysiological tonicity. The daily clinical experience that considerable degrees of plasma hypoosmolality are tolerated in vivo without hemolysis or impairment of oxygen transport by erythrocytes may be explained by the excellent ability of shape adaptation of erythrocytes to each other and to other surfaces such as vascular endothelia. The method of trapped fluid determination might be of potential value as a complementary method in the evaluation of erythrocyte rheology if the amount of trapped fluid is related to the individual erythrocyte.     

Effects of lipids and lipoproteins on thrombosis and rheology

Atherosclerotic plaque rupture and erosions precipitate thrombus formation and may lead to an acute ischemic syndrome. Lipids and lipoproteins modulate the expression and/or function of thrombotic, fibrinolytic and rheologic factors, and thereby influence hemostasis and potential tissue damage resulting from vascular injury. Triglyceride-enriched lipoproteins are accompanied by elevations in factor VII clotting activity, plasminogen activator inhibitor (PAI-1) and viscosity of blood and plasma. Low density lipoprotein (LDL) promotes platelet activation and tissue factor expression and LDL levels correlate with levels of vitamin K dependent coagulation factors and fibrinogen. Conversely, LDL inhibits tissue factor pathway inhibitor (TFPI) which limits activation of the extrinsic coagulation pathway. High density lipoprotein (HDL) has anti-atherothrombotic properties that result from inhibition of platelet and erythrocyte aggregation, reduced blood viscosity and suppression of tissue factor activity and PAI-1 activity and antigen levels. The effects of lipids and lipoproteins on hemostasis and rheology may have important implications for the clinical sequelae following plaque disruption and erosion.     

血液流变学及动力学在妊娠期高血压患者中的变化及临床意义

目的:探讨血液流变学及动力学在妊娠期高血压疾病患者中的变化及临床意义.方法:选择146例妊娠期高血压疾病孕妇(纳入观察组)及同期正常妊娠孕妇145例(纳入对照组)作为研究对象,采用全自动血粘度仪和无创伤监测仪监测两组孕妇血液流变学和血液动力学指标并进行组间比较.结果:观察组全血粘度(包括高切、中切、低切)、血浆粘度、红细胞压积、纤维蛋白原均明显高于对照组,差异有统计学意义(P＜0.05);观察组MAP明显高于对照组,而心输出量(CO)、心脏指数(CI)、心搏量(SV)、心搏指数(SI)及血管顺应性(AC)等则均明显低于对照组,差异均有统计学意义(P＜0.05).结论:监测孕妇血液流变学结合血液动力学指标对妊娠期高血压疾病发生有一定的预测价值,同时根据上述参数变化合理用药以改善患者血液流变学及血液动力学情况,对预防及控制妊娠期高血压疾病的进一步恶化有利.     

How Thick Is Thick? Multicenter Study of the Rheological and Material Property Characteristics of Mealtime Fluids and Videofluoroscopy Fluids

Objective rheological assessment of fluids given to dysphagic patients at mealtime and during videofluoroscopy was carried out using a multicenter format. Thin, quarter-thick, half-thick and full-thick fluids were examined for the degree of correlation between mealtime fluids and their allegedly matched videofluoroscopy counterparts. The study was carried out to determine whether perceived subjective differences between mealtime fluids and videofluoroscopy fluids could be quantified using the rheological parameters of viscosity, density, and yield stress. The results showed poor correlation between mealtime fluids and videofluoroscopy fluids over all parameters. In general, the videofluoroscopy fluids were more viscous, more dense, and showed higher yield stress values than their mealtime counterparts. Given these results, it is reasonable to assume that the fluids used during videofluoroscopy do not provide an accurate indication of swallowing ability at mealtime. Therefore, it is suggested that clinicians use objective methods to rheologically match videofluoroscopy fluids to mealtime fluids.     

A model of the viscoelastic behavior of flowable resin composites prior to setting

Objective

The aim of this study is to develop fractional derivative models for the assessment of viscoelastic properties related to handling characteristics of dental resin composites belonging to two classes: flowable (Revolution Formula 2 and Filtek Ultimate) and posterior “bulk-fill” flowable base (Smart Dentin Replace).

Methods

Rheological measurements on all materials tested in this study were performed using dynamic oscillatory rheometer at temperature of 23 °C. A parallel plates module with a diameter of 20 mm was used to measure the properties of the resin composites tested. We developed two models to describe the obtained data: the generalized Newton model and the generalized Zener model (the so-called three parameter model). Both models contain fractional derivatives of Riemann–Liouville type. By determining the parameters of the model we were able to fit experimental data with high accuracy.

Results

Our results show that flowable “bulk-fill” resin-composite material (SDR) has distinct properties as compared to other two flowable resin composite materials (Revolution Formula 2 and Filtek Ultimate). Thus, previously found SDR properties as “bulk-fill” flowable base results in the fact that it is described by generalized Zener model (i.e., it has properties of solid like viscoelastic material).

Significance

Our model may be used to predict behavior of tested composites in different flow conditions. The SDR has initially small almost constant complex viscosity showing that it has good self-leveling property.