中国健康中老年女性红细胞压积参考值（温氏法）与地理因素的关系

为制定中国健康中老年女性红细胞压积参考值（温氏法）的统一标准提供科学依据。方法分析了３１２个单位１５６０８例健康中老年女性的红细胞压积参考值（温氏法）与５项地理因素的关系。结果发现随着海拔高度的逐渐增大,红细胞压积参考值也逐渐的增大;用数学回归的方法推导出了一个多元回归方程。结论可以依据红细胞压积参考值（温氏法）与地理因素的依赖关系把中国分为青藏区、西南区、西北区、东南区、华北区、东北区等６个区。     

中年男性红细胞压积正常参考值与地理因素的因子分析

目的:为制定中国中年男性红细胞压积正常参考值的统一标准提供科学依据．方法:收集了中国380个地区用温氏法(Wintrobe)测定的32475例健康中年男性红细胞压积正常参考值,运用偏相关分析和因子分析对其与海拔高度(x1),年日照时数(x2),年平均相对湿度(x3),年平均气温(x4),年降水量(x5)的关系进行了研究．结果: 5个地理影响因素值与中年男性红细胞压积正常参考值的偏相关系数分别为: r1,2345=0.651,r2,1345= -0．039,r3,1245=-0．040,r4,1235=-0．281,r5,1234=0．125．运用因子分析将5个地理影响因素综合成两个公共因子F1,F2,并用其得分值代替原始数据推导出一个回归方程: y=48 464 0．1738F1-0.4125F2±4 5％结论:海拔高度是影响中年男性红细胞压积正常参考值的最主要因素．随着海拔高度逐渐增大,中年男性红细胞压积正常参考值也逐渐增大,相关性很显著．如果知道中国某地的地理因素值,可以用公因子的回归方程来估算中国某地的中年男性红细胞压积正常参考值．依据中年男性红细胞压积正常参考值与地理因素的依赖关系把中国分为青藏区,西南区,西北区,东南区,华北区,东北区六个区．     

中国中年男性红细胞压积参考值与海拔高度的关系

红细胞压积是血液流变学的一个重要指标,目前,国内外缺乏血液流变学指标参考值的统一标准,严重影响了临床和科研成果的准确性和可比性,为制定中国中年男性红细胞压积参考值的统一标准提供科学依据,很多人测定了本地区的中年男性红细胞压积参考值,对中年男性红细胞压...     

中年女性红细胞计数正常参考值与地理因素的相关分析

目的：为制定中国中年女性红细胞计数正常参考值的统一标准提供科学依据.方法：收集了中国331个单位用显微镜计数法测定的41003例中年女性红细胞计数正常参考值,运用相关分析和回归分析的方法,研究了其与八个地理因素的关系.结果：发现中年女性红细胞计数正常参考值与中国地理因素之间有很显著的相关关系（F=364.76,P=0.000）.用逐步回归分析的方法推导出了一个回归方程：Y^=4.184＋0.0002421X1-0.02921X4＋0.0002582X7＋0.08144X8±0.47.结论：如果知道了中国某地的地理因素,就可以用回归方程计算这个地区的红细胞计数正常参考值.依据红细胞计数正常参考值与地理因素的依赖关系,把中国分为八个区.     

高原低氧环境下红细胞增多和血液粘度间关系的研究

目的：观察高原低氧环境下人体红细胞增多和血液粘度间的关系。方法：对进入高原不同时间人群进行血液流变学（红细胞压积、血液粘度、红细胞变形性和聚集性以及供氧指数等）检测和分析。结果：（1）红细胞压积和红细胞变形性随进住高原时间的延长而显著升高;（2）血液粘度在进住高原的早期明显升高,后期恢复正常;（3）红细胞的聚焦性在进住高原的早期显著升高,后期则下降;（4）组织供氧指数在进住高原的早期明显降低。而后期恢复正常,结论：在高原低氧环境下,人体血液粘度不随红细胞压积增高按比例升高。红细胞变形性增强和红细胞聚集性下降,可能抑制了红细胞压积增高所引起的血液粘度的过度升高,从而有助于维持组织的正常供氧。     

临产孕妇血液流变性研究

研究临产孕妇血液流变性的11项指标的改变,并与健康育龄妇女进行对照.结果表明临产孕妇体外血栓形成的长度、血栓湿重、血栓干重、血浆比粘度、红细胞电泳时间及血沉方程K 值等均明显高于对照组(P<0.01).全血比粘度与红细胞压积低于对照组(P<0.05),全血还原粘度、红细胞内粘度和 TK 值在两组间无显著差异.认为在妊娠后期孕妇血液呈高凝状态.其主要原因是红细胞聚集性增高及血浆粘度增高,与红细胞变形能力及红细胞压积关系不明显.文中还探讨了各因素的相互影响。     

甘肃鼢鼠血象及其与低氧适应的关系

甘肃鼢鼠(Myospalax cansus)是一种严格营地下生活的鼠类,其形态、行为及生理特征均与地面鼠不同。为探讨甘肃鼢鼠适应低氧环境的机理,本研究采用血象指标测定方法,对甘肃鼢鼠低氧适应前后的红细胞数、血红蛋白浓度、红细胞压积等各血象指标进行测定。结果显示,甘肃鼢鼠低氧适应后红细胞数、血红蛋白浓度和红细胞压积均显著升高,而平均红细胞体积、平均红细胞血红蛋白及平均红细胞血红蛋白浓度明显下降。与地面生活的啮齿动物低氧适应后血象相比,甘肃鼢鼠红细胞数量多,红细胞压积大,血红蛋白浓度高,红细胞膜表面积大,血红蛋白的利用率较高,可能是对低氧环境适应的一种途径。     

血液粘弹性测量的标准化及其实验研究

提出一种关于血液粘弹性测量的校正方案.一套关于平均切变率(或测头振动频率)、抗凝剂、红细胞压积和红细胞聚集等因素对粘弹性测量值影响的实验证实了这一方案的可用性.同时,实验结果表明,尽管红细胞压积的影响十分显著,仍然可以通过定义一个新的复数型的粘弹性参数L~(?)来消除这一影响.因此,该参数对建立血液粘弹性的人群正常值范围有实际意义,实验结果还显示、测量时用EDTA作抗凝剂为宜.     

小鼠骨髓和周围血细胞值与鼠龄性别的关系

本文报道615、C_(57)BL和昆明种小鼠骨髓和周围血细胞值与鼠龄、性别的关系。年龄体重相似的C_(57)BL小鼠血小扳、红细胞压积和昆明种小鼠红细胞压积、网织红细胞值雌雄间相差显著。在一定年龄范围内,如30周龄昆明种小鼠和34周龄615小鼠与其同种9—13周龄鼠比较,白细胞分类组分间大部差异显著。昆明种小鼠4个月动态观祭期间除红细胞压积外,其余各项指标随年龄的增长皆趋向下降。骨髓有核细胞数和分类不同鼠龄间也示显著差异。     

机械通气对慢性阻塞性肺疾病患者红血球变化的影响

目的:评价机械通气治疗对慢性阻塞性肺疾病(COPD)患者红血球变化的影响.方法:采用病例报告表,收集我院ICU2004年-2008年收治的67例COPD行机械通气患者的血球分析及血气分析,建立数据库:①测定67例COPD患者机械通气前、通气1天、通气7天后红细胞计数、血红蛋白、红细胞压积以及氧分压值,评估机械通气对COPD患者红血球变化的影响.②根据预后分为生存组和死亡组:比较两组通气前与通气1天、7天后红血球分析变化值.③以65岁为界分为低龄组和高龄组,比较两组通气前与通气1天、7天的红血球分析变化值.结果:①机械通气后红细胞计数、血红蛋白、红细胞压积随时间均明显降低,氧分压明显升高(P<0.05).②生存组和死亡组通气前后红血球分析变化值随时间变化有显著差异.③高龄组和低龄组通气前后红血球分析变化值无明显差异.结论:COPD患者行机械通气治疗后红细胞计数、血红蛋白、红细胞压积随时间增加明显降低,其变化影响预后,应尽早拔除气管插管,缩短有创机械通气时间,缩短ICU和总住院时间,有效改进治疗效果,降低治疗费用,是具有一定临床实用价值的治疗方案.     

Influence of age and hematocrit on the coagulation of blood

To examine the effects of age, hematocrit and the daily variation in hematocrit on coagulation of blood, the time of onset of coagulation (Ti) of whole blood obtained from donors including normal subjects and patients was measured by means of a rheological technique. The Ti value of recalcified blood decreased with an increase in age, but in donors aged 65 years or more (the elderly), the Ti value was almost independent of age. The Ti value for blood obtained from the elderly was significantly lower at lower hematocrit levels, but that for blood obtained from young donors was almost independent of hematocrit. The daily variation in hematocrit in individuals was small (maximum variation: about 4%), and the variation had little effect on the Ti value. However, a slight increase in hematocrit was considered to bring about a significant increase in viscosity at lower shear rates. Therefore, it is suggested that a slight increase in hematocrit under stagnant flow conditions is one of major risk factors for venous thrombogenesis, especially in the elderly.     

Dynamics of blood flow: modeling of Fåhraeus and Fåhraeus–Lindqvist effects using a shear-induced red blood cell migration model

Blood flow in micro capillaries of diameter approximately 15–500 μm is accompanied with a lower tube hematocrit level and lower apparent viscosity as the diameter decreases. These effects are termed the Fåhraeus and Fåhraeus–Lindqvist effects, respectively. Both effects are linked to axial accumulation of red blood cells. In the present investigation, we extend previous works using a shear-induced model for the migration of red blood cells and adopt a model for blood viscosity that accounts for the suspending medium viscosity and local hematocrit level. For fully developed hematocrit profiles (i.e., independent of axial location), the diffusion fluxes due to particle collision frequency and viscosity gradients are of equal magnitude and opposite directions. The ratio of the diffusion coefficients for the two fluxes affects both the Fåhraeus and Fåhraeus–Lindqvist effects and is found related to the capillary diameter and discharge hematocrit using a well-known data-fit correlation for apparent blood viscosity. The velocity and hematocrit profiles were determined numerically as functions of radial coordinate, tube diameter, and discharge hematocrit. The velocity profile determined numerically is consistent with the derived analytical expression and the results are in good agreement with published numerical results and experimental data for hematocrit ratio and hematocrit and velocity profiles.     

Evaluation of viscoelasticity measurements of human blood

The dependence on hematocrit of whole blood viscoelasticity must be considered in order to compare pathological blood samples to normal ones. If one wants to calculate the measured values to a standard hematocrit value, the hematocrit dependence for the pathological sample must be available. As the latter however is unknown, the same dependence is assumed for both normal and pathological blood samples. To prove the validity of this assumption, hematocrit dependence of random blood samples from different diseases (cerebral and coronary vascular and myocardial disorders) were investigated. A statistical analysis showed the assumption as invalid. Therefore, it will be recommended to evaluate pathological blood samples at the measured hematocrit.     

Comparison of various approaches to calculating the optimal hematocrit in vertebrates

An interesting problem in hemorheology is to calculate that volume fraction of erythrocytes (hematocrit) that is optimal for transporting a maximum amount of oxygen. If the hematocrit is too low, too few erythrocytes are present to transport oxygen. If it is too high, the blood is very viscous and cannot flow quickly, so that oxygen supply to the tissues is again reduced. These considerations are very important, since oxygen transport is an important factor for physical performance. Here, we derive theoretical optimal values of hematocrit in vertebrates and collect, from the literature, experimentally observed values for 57 animal species. It is an interesting question whether optimal hematocrit theory allows one to calculate hematocrit values that are in agreement with the observed values in various vertebrate species. For this, we first briefly review previous approaches in that theory. Then we check which empirical or theoretically derived formulas describing the dependence of viscosity on concentration in a suspension lead to the best agreement between the theoretical and observed values. We consider both spatially homogeneous and heterogeneous distributions of erythrocytes in the blood and also possible extensions, like the influence of defective erythrocytes and cases where some substances are transported in the plasma. By discussing the results, we critically assess the power and limitations of optimal hematocrit theory. One of our goals is to provide a systematic overview of different approaches in optimal hematocrit theory.     

UNDERSTANDING AND INTERPRETING HEMATOCRIT MEASUREMENTS IN PINNIPEDS

Hematocrit data are relatively easily obtained from blood samples of pinnipeds but differences in methodology and variable physiological conditions of the subjects can significantly alter their values. This two-fold problem makes comparative data and modeling efforts difficult. To quantify the difficulty of obtaining accurate and representative hematocrit values in pinnipeds, hematocrit was measured by both microcentrifugation and Coulter counter methods in a range of pinnipeds under a variety of physiological and handling conditions. The data show that the Coulter counter hematocrit values were 4%-15% higher than those measured by microcentrifugation. In addition, blood samples from restrained animals showed consistently elevated hematocrit values relative to resting subjects. A significant difference was also found between hematocrit values from pups and adults. Finally, hematocrit was shown to decline over the course of isofluorane anesthesia. Taken together, these results suggest that laboratory methodology, developmental state, and animal handling techniques can significantly alter hematocrit values in pinnipeds. Thus, modeling efforts that require representative hematocrit values, such as calculations of total blood oxygen stores, can be markedly impacted by variations in hematocrit measurement techniques and sampling regimes.     

Hematocrit,age, and survival in a wild vertebrate population

Understanding trade‐offs in wild populations is difficult, but important if we are to understand the evolution of life histories and the impact of ecological variables upon them. Markers that reflect physiological state and predict future survival would be of considerable benefit to unraveling such trade‐offs and could provide insight into individual variation in senescence. However, currently used markers often yield inconsistent results. One underutilized measure is hematocrit, the proportion of blood comprising erythrocytes, which relates to the blood's oxygen‐carrying capacity and viscosity, and to individual endurance. Hematocrit has been shown to decline with age in cross‐sectional studies (which may be confounded by selective appearance/disappearance). However, few studies have tested whether hematocrit declines within individuals or whether low hematocrit impacts survival in wild taxa. Using longitudinal data from the Seychelles warbler (Acrocephalus sechellensis), we demonstrated that hematocrit increases with age in young individuals (<1.5 years) but decreases with age in older individuals (1.5–13 years). In breeders, hematocrit was higher in males than females and varied relative to breeding stage. High hematocrit was associated with lower survival in young individuals, but not older individuals. Thus, while we did not find support for hematocrit as a marker of senescence, high hematocrit is indicative of poor condition in younger individuals. Possible explanations are that these individuals were experiencing dehydration and/or high endurance demands prior to capture, which warrants further investigation. Our study demonstrates that hematocrit can be an informative metric for life‐history studies investigating trade‐offs between survival, longevity, and reproduction.     

Regional lung hematocrit in humans using positron emission tomography

Regional lung hematocrit ratio (R) was measured in five normal subjects and five patients (2 with pneumonia, 2 with nephrotic syndrome with anemia, and 1 with pancreatitis) using positron emission tomography, a red cell marker 11CO, and a plasma marker [methyl-11C]albumin). The measurements were made in a transaxial thoracic section at midheart level with the subject in supine posture and with a spatial resolution of 1.7 cm. The normal regional hematocrit ratio (means +/- SE) calculated for the lung was 0.90 +/- 0.014, 0.94 +/- 0.023 for the thoracic wall, and 1.00 +/- 0.003 for the heart chambers. The regional lung hematocrit ratio in the patients ranged between 0.81 and 0.86. No correlation was found among the regional lung hematocrit ratio and regional blood volume, lung extravascular density, and the peripheral hematocrit (obtained from venous blood samples). To the extent that 70% of the pulmonary blood in the field of view is in larger vessels with normal hematocrit, the hematocrit in the capillary bed is approximately two-thirds that of the peripheral venous value. Blood volume measurements on the basis of single vascular tracers need to take account of these results.     

The Fahraeus effect in sheet flows with a gap thickness of 4 to 36 microns

We measured the Fahraeus effect of blood flowing in a sheet flow model formed with two glass slides. The number of red blood cells in the sheet flow was counted to determine a sheet hematocrit Hs and the discharge hematocrit Hd was measured from blood collection. For a Hd in the range of 3 to 30 percent, we find that Hs/Hd is about .83 for a gap of 4.1 microns. When the discharge hematocrit is 30 percent, the ratio decreases to .66 as the gap approaches 7 microns and then increases as the gap becomes thicker. The results indicate that the hematocrit ratio for a gap thicker than 4.1 microns is an increasing function of the discharge hematocrit. The value of Hs/Hd found for the sheet flow models and its dependence on Hd are comparable to those of circular tubes when their diameter equals the gap thickness.     

Experimental manipulation of tail ornament size affects the hematocrit of male barn swallows (Hirundo rustica)

Ornamental tail feathers of male barn swallows (Hirundo rustica) confer an advantage in sexual selection because long-tailed males are preferred by females. However, the size of tail ornaments exceeds the natural selection optimum and males are predicted to pay an energetic cost for flying, directly related to tail length. An increase in hematocrit is an adaptive response to enhance oxygen uptake, for example during periods of intense locomotory activity. In this study, we analyzed the effect of experimental manipulation of tail length on the hematocrit of male barn swallows from an Italian and a Spanish population. We predicted that the natural decrease in hematocrit during the breeding season would be reduced by experimental elongation and enhanced by experimental shortening of tail ornaments. The results showed that the decrease in hematocrit was significantly different among tail treatments, and tail-elongated males had the smallest hematocrit reduction. In Italy, the hematocrit of tail-elongated males did not change after tail manipulation, while that of two control groups and tail-shortened males decreased. A comparatively high hematocrit in males with experimentally enlarged tail ornaments may be a response to increased energetic requirements and, hence, to oxygen demands for flying imposed by their tail morphology. Received: 22 June 1996 / Accepted: 23 October 1996     

Calorimetric studies of oxyhemoglobin dissociation. II. Erythrocytic oxygen depletion by sodium dithionite

Dithionite causes the depletion of dioxygen from suspensions of erythrocytes by reduction of the external dioxygen and not by diffusion into the cell. The molar enthalpy for the reduction shows a small difference with respect to the values found for free hemoglobin; and the normal stoichiometry of 2 moles dithionite/mole dioxygen found there is not observed with erythrocytes. At low hematocrit, the stoichiometry is 2.6:1 and decreases to 1.5:1 at high hematocrit. The change is not due to differences in the hemoglobin saturation or to an inability of dithionite to reduce all dioxygen present at the higher hematocrit. Neither catalase nor peroxidase added to the extracellular volume significantly alters the stoichiometry or the enthalpy of dioxygen reduction by dithionite. Addition of superoxide dismutase, however, restores the normal stoichiometry at high hematocrit and further increases the stoichiometry at low hematocrit. The calorimetrical signal of hydrogen peroxide, clearly seen with free dioxygen, is not present with erythrocytes. In all these cases the total heat evolved is the same.