Decreased osmotic fragility in heritable canine myopathy

Osmotic fragility was examined in red blood cells from dogs with a heritable muscle disorder that clinically resembles a muscular dystrophy. Several erythrocyte abnormalities have been reported in partients with certain forms of muscular dystrophy and it is thought that these changes reflect genetically induced alterations in the plasma membrane. It is believed that the examination of erythrocytes may eventually lead to the understanding of membrane involvement in muscle disorders. In this study, the mean osmotic fragility was found to be significantly lower in affected cells than in normal cells. These differences were maintained regardless of changes in incubation temperature (5°, 20°, or 35°C) and pH (6.5. 7.0, 7.5. or 8.0). Quantitative analysis of glycolytic metabolites and adenine nucleotide concentrations revealed little variance between erythrocytes from normal and affected animals. Similarly, the pattern of membrane protein phosphorylation in intact crythrocytes from affected animals did not differ from that observed when erythrocytes from normal animals were examined. Of the red cell indices measured, the erythrocyte count in affected animals was moderately increased, but both the mean corpuscular volume and mean corpuscular hemoglobin content were significantly reduced. From these data it is concluded that the decrease in osmotic fragility cannot be explained by differences in cell metabolism or energy production. However, the decrease in affected cell mean corpuscular volume and mean corpuscular hemoglobin content may be correlated with the decrease in osmotic fragility in a manner similar to that observed in the hemolytic disorder of beta-thalassemia.     

Continuous flow method for determination of erythrocyte osmotic fragility

A simple and accurate micromethod for the determination of erythrocyte osmotic fragility is introduced. The method uses a laminar parabolic flow pattern, together with gravity, to retain cells in a long, small-diameter tube while a solution with decreasing osmolarity is passed through the tube. As the cells hemolyze, hemoglobin released from the cells is quickly removed by the axial flow pattern and monitored with a 547 nm optical detector for recording the hemolysis curve. Consequently, a continuous curve is obtained, with a peak occurring at the salt concentration that produces the maximum hemolysis rate. The advantages of this method are simplicity, accuracy, and small sample size (2 microliters of whole blood). The small sample size is of particular importance for infants. A comparison is made with the Parpart method using samples from 18 normal adults. Results are also given for a few abnormal adults and for a series of 26 normal newborns.     

Osmotic Erythrocyte Fragility and ABO Blood Groups

In a study of 1008 blood donors a reduced frequency of blood group A and an increased frequency of blood group O were observed in those with increased osmotic fragility of their red cells.     

Evaluation of single-tube osmotic fragility as a screening test for thalassemia

A single-tube osmotic fragility test has been proposed for thalassemia screening with a range of different concentrations of saline having been employed. We have compared the sensitivity and specificity of 0.32%, 0.34%, and 0.36% buffered saline, and on the basis of our findings, recommend the use of 0.36% saline. This gave definitely positive or equivocal results in 81 of 85 patients with beta thalassemia trait and in 4 of 4 with alpha(0) thalassemia trait. There were 14% false positive results in hematologically normal patients and 81% of the samples from patients with various variant hemoglobins gave positive results. The sensitivity was 95% and specificity 86%. The single-tube osmotic fragility test is potentially useful in under-resourced laboratories although it cannot replace automated red cell indices using electronic counters.     

Cryohemolysis for the detection of hereditary spherocytosis: Correlation studies with osmotic fragility and autohemolysis

Laboratory methods aimed to assess the presence of spheroidal cells such as osmotic fragility, autohemolysis, and glycerol lysis time are very elaborate, time consuming, and often give inconclusive results. We have developed a diagnostic test based on a unique sensitivity of HS cells to hypertonic cryohemolysis and analyzed blood samples of 55 HS patients. The patients were divided into two subgroups, clinically affected probands and their relatives. To get quantitative comparisons with the classic methods, the cryohemolysis results were compared to two parameters of the osmotic fragility test: the salt concentration that causes 50% hemolysis, and the percent lysis at a constant salt concentration. Autohemolysis results were also compared. To evaluate which of these tests has the best analytical power, we calculated the mean results and 2 SDs of each parameter in a control group, and then looked to see which of them was best in identifying the patients. The cryohemolysis test was the single parameter that identified all cases including asymptomatic carriers of the disease. The ability of this test to identify the less severe cases probably reflects the dependency of the cryohemolysis on factors that are more related to the primary membrane molecular defects and less by the surface area to volume ratio. Am. J. Hematol. 58:206–212, 1998. © 1998 Wiley-Liss, Inc.     

Combined effect of dextrose and sodium chloride on red cell osmotic fragility

Observations indicating an enhancing effect of sodium on hemolysis of red cells suspended in dextrose solution prompted study of the mechanism of this effect. Osmotic fragility of red cells from normal subjects and from patients was measured in 5% dextrose solution (5D/W), 5% dextrose combined with various concentrations of sodium chloride (5D/NaCl), lithium chloride, and potassium chloride. The influence of ouabain on osmotic hemolysis in 5D/ NaCl was also studied, and the glucose content of ghost red cells was determined when incubated in 5% dextrose with 0.05% NaCl (5D/O.05NaCl), as compared with 5D/W. In the presence of minimal amounts of NaCl (0.05%) at pH 4.8, average hemolysis was greater than in the absence of NaCl, ie, 39% vs 24% in normal subjects (P < 0.02) and 40% vs 31% in a group of unselected patients (P < 0.05). When the pH was adjusted to 7.4 in the patient group, the results were 34% vs 21% (P < 0.05). The sodium-induced enhancement of hemolysis in dextrose solution was virtually duplicated when LiCl and KCl were substituted for NaCl (P < 0.01 and < 0.05, respectively). On the other hand, in the presence of ouabain, the sodium-induced enhancement of hemolysis was abolished. The overall glucose content of ghost red cells incubated in 5D/0.05NaCl was 53% greater than in 5D/W (P < 0.005), whereas with ghost red cells depleted of adenosine triphosphate (ATP), it was only 32% greater (P < 0.01). These results suggest that glucose transport across the red cell membrane is enhanced by the sodium ion, presumably by triggering the membrane sodium-potassium ATPase system.     

Modified osmotic fragility test for the laboratory diagnosis of hereditary spherocytosis

A modified osmotic fragility test, based on measurement of hemolysis in four hypotonic NaCl solutions and logarithmic linearization of osmotic fragility curve is, like the "Pink test," a specific and sensitive test for the laboratory diagnosis of hereditary spherocytosis.     

联合试验在地中海贫血诊断中的应用

目的 :探讨红细胞平均体积 (MCV)、红细胞脆性及血红蛋白 (Hb)电泳联合试验在地中海贫血 (简称地贫 )中的诊断价值。方法 :用日本SysmexKX 2 1自动血细胞分析仪、中山医科大学红细胞脆性一管定量法、美国Helena公司KEP型全自动电泳分析系统 ,分别对本实验室经分子生物学技术确诊的 14 8例地贫及 81例非地贫样品进行MCV、红细胞脆性及Hb电泳测定 ,并对结果作相关统计学分析。结果 :MCV、红细胞脆性、Hb电泳单项试验对地中海贫血诊断的灵敏度及特异度分别为 91.9%、81.1%、83.8%及 79%、91.4 %、90 .1%。MCV与Hb电泳、红细胞脆性与Hb电泳二项试验平行联合的灵敏度及特异度分别为 98.6 %、96 .6 %及 71.6 %、82 .7% ;系列联合的灵敏度及特异度分别为 77%、6 8.2 %及 97.5 %、98.8%。MCV、红细胞脆性、Hb电泳三项试验平行联合的灵敏度、特异度为 10 0 %、6 5 .4 % ;系列联合的灵敏度及特异度为 6 2 .8%、10 0 %。经u检验 ,平行联合试验的灵敏度与各单项试验灵敏度之间、系列联合试验的特异度与各单项试验特异度之间差异有统计学意义 (P <0 .0 5 )。结论 :在地贫的诊断试验中 ,MCV、红细胞脆性、Hb电泳平行联合试验可提高灵敏度 ,系列联合试验可提高特异度 ,联合试验较单项试验有一定的优越性     

Red cell osmotic fragility studies in hemoglobin C‐β thalassemia: osmotically resistant microspherocytes

Typically certain features of red cell morphology predict the results of osmotic fragility testing. Microspherocytes generally have increased and target cells decreased fragility. Blood smears in homozygous hemoglobin C disease show an interesting admixture of microspherocytes and target cells. Yet osmotic fragility studies generally show only reduced fragility and no population of fragile cells to correspond with the spherocytes. The present study demonstrates that the red cells of patients with hemoglobin C‐β thalassemia share many characteristics with hemoglobin C red cells, including the decreased osmotic fragility of all cells despite the presence of both spherocytes and target cells. These paradoxically osmotically resistant spherocytes probably arise because of cellular dehydration due to a K‐Cl transport system which may be activated by binding of hemoglobin C to the red cell membrane.     

Comparison of acidified glycerol lysis test, Pink test and osmotic fragility test in hereditary spherocytosis: effect of incubation

In this study we compared the results of the acidified glycerol lysis test, the Pink test and the osmotic fragility test in 38 patients with hereditary spherocytosis and in healthy controls. The sensitivity of the acidified glycerol lysis test was 81.6% when performed within 3 h after blood collection. After incubating for 24 h, the sensitivity increased to 100% whereas the specificity remained maximal. Similar incubation did not improve the diagnostic utility of the Pink test. All patients, but none of the controls, showed a positive osmotic fragility test. It is concluded, because of sensitivity and specificity in this study, that the acidified glycerol lysis test after incubation and the osmotic fragility test are superior to the Pink test in detecting spherocytosis.     

The occurrence of oxidative stress during reperfusion in experimental animals and men

Reperfusion is the prerequisite for the ischemic myocardium to recover its metabolic and mechanical function. However, reperfusion after a prolonged period of ischemia in the experimental animal may exacerbate, or at least accelerate, the occurrence of ischemic injury, whilst in humans at the least it is not beneficial. This entity has been called reperfusion damage, since much of the damage is believed to be caused by events occurring at the moment of reperfusion rather than by changes occurring during ischemia. The existence of reperfusion damage, however, has been questioned, and evidence in favour of the concept is sparse. At the moment the molecular events occurring at the time of reperfusion are not completely understood, and the relative importance of several proposed deleterious mechanisms is not yet established. One of the most fashionable ideas for the cause of reperfusion damage is that the function of cell membrane is modified by oxygen radicals generated at the moment of reperfusion. Evidence in favour of and against this hypothesis is described in detail in the present article.     

Glutathione,oxidative stress and aging

The free radical theory of aging proposes that the impairment in physiological performance associated with aging is caused by the detrimental effects of oxygen free radicals. This is interesting because it provides us with a theoretical framework to understand aging and because it suggests a rationale for intervention, i.e., antioxidant administration. Thus, the study of antioxidant systems of the cell may be very important in gerontological studies. Glutathione is one of the main nonprotein antioxidants in the cell which, together with its related enzymes, constitute the “glutathione system.” The involvement of glutathione in aging has been known since the early seventies. Several studies have reported that reduced glutathione is decreased in cells from old animals, whereas oxidized glutathione tends to be increased. Recent experiments from our laboratory have underscored the importance of cellular compartmentation of glutathione. Mitochondrial glutathione plays a key role in the protection against free radical damage associated with aging. Oxidative damage to mitochondrial DNA is directly related to an oxidation of mitochondrial glutathione. In fact, aging is associated with oxidative damage to proteins, nucleic acids, and lipids. These molecular lesions may be responsible for the low physiological performance of aged cells. Thus, antioxidant supplementation may be a rational way to partially protect against age-associated impairment in performance. Apoptosis, a programmed cell death, is an area of research which has seen an explosive growth. Glutathione is involved in apoptosis: apoptotic cells have lower levels of reduced glutathione, and administration of glutathione precursors prevent, or at least delay, apoptosis. Age-associated diseases constitute a major concern for researchers involved in aging. Free radicals are involved in many such diseases; for instance, cancer, diabetes or atherosclerosis. The key role of glutathione and other antioxidants in the pathophysiology of aging and age-associated diseases is discussed in this review.     

Membrane-bound iron contributes to oxidative damage of beta-thalassaemia intermedia erythrocytes

Iron-dependent oxidative reactions in beta-thalassaemic erythrocyte membranes are involved in premature cell removal and anaemia. We studied 22 beta-thalassaemia intermedia patients (i) to assess if membrane iron accumulation influences the oxidative damage to thalassaemic cells, and (ii) to see whether the mechanisms of haemoglobin destabilization described in vitro have indicators in circulating erythrocytes. Serum non-transferrin-bound iron as potentially toxic iron for erythrocytes was also evaluated. Membrane-bound free iron significantly correlated to bound haemichromes, suggesting a causal relation, but was poorly related to serum non-transferrin iron, which seems to contribute little to damage from outside the cells. The spleen played an important role in the removal of cells with more membrane iron.     

酒精性肝病与氧化应激

酒精性肝病(ALD)是威胁人类健康的重大疾病之一,其发病机制错综复杂。氧化应激性肝损害在其中占有至关重要的地位,如何系统的认识机体的氧化与抗氧化系统在ALD发生发展过程中所扮演的角色,对ALD的防治工作具有一定的指导意义。     

氧化应激/还原应激在心力衰竭中的研究进展

氧化应激自1985年由德国科学家Sies第一次提出之后,关于氧化应激的研究已有30多年历史,且从未中断。国内外大量研究已经证实氧化应激参与心力衰竭的发生和发展。针对临床前环境中的抗氧化应激治疗也进行了广泛研究,并显示出非常有希望的结果,但是目前临床上采用的大多数抗氧化策略都未能改善心力衰竭患者的预后。原因可能是大部分研究忽略了还原应激的损伤作用。本文将概述心力衰竭时氧化应激/还原应激的变化特点,以期为未来抗氧化/还原应激方向提供新的见解。     

动脉粥样硬化的氧化应激生物标记物研究进展

越来越多的证据表明,氧化应激在动脉粥样硬化(AS)性心血管疾病形成中的重要作用。最近的一些病理学方面的研究也发现,某些特异性的调节物参与了这些氧化应激反应并可促进AS斑块在血管壁的形成和破裂。这些特异性的调节物能在人体内测出并作为AS性心血管疾病风险评估的生物标记物,本文就这些生物标记物作一综述。     

Erythrocyte osmotic fragility in various liver diseases--application of coil planet centrifuge system

A change in erythrocyte osmotic fragility was observed on various liver diseases by means of the coil planet centrifuge (CPC) system, and the relationship between changes in it and in serum lipids was studied. According to the CPC classification of hemolytic patterns of L, M, T and R, the frequency of appearance of T and R increased in liver cirrhosis and primary hepatoma. Hemolytic start and end points both changed considerably in primary hepatoma, acute hepatitis and liver cirrhosis. Change of hemolytic end point which shifted to the hypotonic side is more prominent than that of hemolytic start point. The hemolytic end point showed an inverse correlation to serum alkaline phosphatase and LAP, and correlation to pseudocholinesterase and albumin. Among the relations of red cell fragility and lipids of the lipoprotein fractions, free cholesterol and the ratio of free cholesterol to phospholipid in high density lipoprotein were both in remarkable inverse correlation to the hemolytic end point. Free cholesterol in high density lipoprotein was concluded one of the most important determinants of erythrocyte osmotic fragility.