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At least 19 recordsLinked to original sources
PubMed1985

Studies on retinitis pigmentosa in man. II. Erythrocyte osmotic fragility.

The osmotic fragility of erythrocytes from patients with genetically classified forms of retinitis pigmentosa (RP) has been studied. The mean fragility was increased in autosomal dominantly inherited RP, where the dystrophy was expressed regionally in the retina, with both rods and cones affected. In contrast it was normal in patients with the dominantly inherited disease, which leads to a diffusely distributed dystrophy of, predominantly, rod photoreceptor cells. Raised osmotic fragility of erythrocytes has also been observed in female patients with multiplex (recessive) RP and in female carriers of the X-linked form of the disease.

Adult↗
PubMed1977

The erythrocyte membrane site for the effect of temperature on osmotic fragility.

The osmotic fragility of human erythrocytes is well known to decrease as the temperature is elevated. The cellular site for the temperature effect was studied by assessing possible roles of hemoglobin and of membrane lipids and by taking advantage of the unique response of camel erythrocytes to temperature. It is concluded that the erythrocyte membrane is the site for the temperature effect on osmotic fragility. The human erythrocyte is likely to rupture in protein--lipid boundary regions in the membrane, from which cholesterol is apparently excluded.

Animals↗
PubMed1985

Porcine malignant hyperthermia susceptibility: erythrocytic osmotic fragility.

Erythrocyte osmotic fragility was determined in 27 Pietrain swine which were susceptible to malignant hyperthermia (MH), 29 Yorkshire swine which were resistant to MH (controls), and 50 crossbred swine (Pietrain x Yorkshire), half of which were MH susceptible. Halothane challenge tests and blood creatine kinase activity were used as criteria for determining MH susceptibility. Mean values for osmotic fragility of erythrocytes in concentrations of NaCl between 60 and 120 mM were significantly different for the 3 groups (P less than 0.001). Hemolysis (50%) of erythrocytes occurred at NaCl concentrations of 90 mM for Pietrains, 85 mM for crossbreds, and 78 mM for controls. Increased fragility values occurred in 96% of the Pietrains, 3% of the controls, and 42% of crossbred swine that were halothane test-positive, and 58% of halothane test-negative crossbreds (P less than 0.05). The mean time of onset of signs of MH in response to halothane challenge testing was twice as long in the crossbreds as in Pietrains (P less than 0.01). Reticulocyte counts were moderately high in blood samples from both the Pietrains (P less than 0.001) and the crossbreds (P less than 0.05). Of the swine which were tested for erythrocyte selenium-dependent glutathione peroxidase activity, values were within acceptable laboratory limits in 18 of 20 Pietrains, 14 of 14 halothane test-negative crossbreds, and 8 of 8 halothane test-positive crossbreds. In 2 of 20 Pietrains, a 35% deficiency of this enzyme was found. Heinz bodies were not detected in erythrocytes examined from 21 Pietrains, 20 crossbred swine (8 halothane test positives), and 12 controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[The effect of Eperythrozoon suis infection on the osmotic fragility of erythrocytes].

Osmotic fragility of erythrocytes was tested in weaned pigs experimentally infected with Eperythrozoon (E.) suis. Acute eperythrozoonosis of splenectomized pigs led to an increase of osmotic fragility. It is supposed that E. suis infection causes a structural change in erythrocyte membrane. Possible mechanisms of this cell membrane injury are discussed.

Animals↗
PubMed1981

Age as a factor affecting erythrocyte osmotic fragility in males.

Osmotic fragility and erythrocyte dimensions were measured in 40 normal males between the ages of 18 and 78 years. The principal independent variables correlating with osmotic fragility were mean cell haemoglobin concentration and the age of the donor. The age-related effect was shown to increase both the mean fragility of the cells and the variability of the fragilities of the cells within the individual blood sample. The physical basis for the change is an increase in the degree of isometric sphering of the erythrocytes at isotonicity. The change in shape does not appear sufficient to affect capillary perfusion significantly in normal subjects, but suggests that cell shape will increase the vulnerability of the elderly to abnormalities of the microvasculature.

Adolescent↗
PubMed1998

The effect of EDTA as an anticoagulant on the osmotic fragility of erythrocytes.

The osmotic fragility test is used to determine the extent of red blood cell haemolysis produced by osmotic stress. Since the quality of this test may easily be influenced by environmental and technical factors we have determined osmotic fragility reference values in our own conditions. The results show significantly increased osmotic resistance of erythrocytes in our conditions vs the published values for blood samples anticoagulated with heparin. Furthermore, the use of EDTA as an anticoagulant increased the osmotic fragility of red blood cells as compared with heparin. We conclude that EDTA can be used as an anticoagulant for the osmotic fragility test in order to simplify routine procedures. However, every laboratory should determine its own reference values which would reflect the local environmental and technical factors.

Adolescent↗
PubMed1983

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 patients 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 degrees, 20 degrees, or 35 degrees 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 erythrocytes 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.

Adenine Nucleotides↗
PubMed1984

A genetic study of red cell osmotic fragility in Huntington's disease.

The erythrocyte osmotic fragility was evaluated on 19 unmedicated subjects with Huntington's disease and 42 individuals at 50% risk, 27 children at 25% risk, and a group of 60 hematologically normal control persons. Five older subjects at 50% risk for Huntington's disease as well as 6 Alzheimer's disease individuals were also evaluated for comparison. The osmotic fragility of fresh and 24-hour incubated red cells was analyzed and a fragility index calculated for each individual. The fragility index for the Huntington's disease group was statistically lower than that of the control group (P less than .001) suggesting that the Huntington's disease erythrocytes had a reduced osmotic fragility. In the 50% risk group, 45% of the subjects demonstrated decreased osmotic fragility and 55% had normal fragility. For those subjects in the 25% risk group, 22.2% had decreased fragility and 77.8% had normal fragility. Twenty-seven offspring were evaluated of the 14 persons at 50% risk for Huntington's disease with children; eight of the 14 individuals at 50% risk showed normal fragility and all 16 of their children showed fragility indices with the normal range. The remaining six persons at 50% risk for Huntington's disease had increased erythrocyte fragility and out of their 11 children, five showed normal fragility and six had decreased fragility. These data support the hypothesis of reduced erythrocyte osmotic fragility in individuals affected with and at risk for Huntington disease, and demonstrate the need of further study of the erythrocyte in this complex behavioral genetic disease.

Adolescent↗
PubMed1976

Adaptation of an osmotically fragile L-form of Streptococcus pyogenes to physiological osmotic conditions and its ability to destroy human heart cells in tissue culture.

An osmotically fragile L-form of Streptococcus pyogenes, type 12, was quickly rendered osmotically stable by decreasing the sodium chloride content of the growth medium and with the temporary use of oleic acid. The change from osmotic fragility to stability was accompanied by changes in cell yield, generation time, saturated/unsaturated fatty acid ratio of the membrane, and cytoplasmic protein composition. Finally, this resulting osmotically stable L-form survived and was capable of rapidly destroying Girardi human heart cells in tissue culture.

Cell Survival↗
PubMed1982

Increased erythrocyte osmotic fragility in pregnancy.

An unexpected increase in erythrocyte osmotic fragility during pregnancy in two healthy women prompted a study of the effects of pregnancy on osmotic fragility. The incubated glycerol lysis time, a rapid, sensitive measure of osmotic fragility, was determined in 100 pregnant women and 50 nonpregnant control subjects. Twenty-two of the pregnant women (22%) showed abnormal results when compared to normal nonpregnant women (p less than 0.0005). Increased erythrocyte fragility was observed primarily in the last trimester of pregnancy. Twenty-one of 65 women in the last trimester (32.3%) had abnormal incubated glycerol lysis time values, but only one of 34 (2.9%) showed increased fragility during early pregnancy. Physiologic shifts in erythrocyte osmotic fragility may create a problem in the diagnosis of hereditary spherocytosis during the last trimester of pregnancy.

Adult↗
PubMed1979

[Changes in the osmotic fragility of erythrocyte membrane in morphine- and phenobarbital-dependent rats (author's transl)].

This is apparently the first attempt to elucidate the relationship between drug dependence and the osmotic fragility of erythrocyte membrane. The osmotic fragility was measured using a coil planet centrifuge (CPC) system. Utilizing the drug-admixed food (DAF) method, rats were made drug-dependent. The osmotic fragility of morphine-dependent rats was significantly enhanced, compared with that of naive rats. By withdrawing or treating the rats with levallorphan, the osmotic fragility was enhanced more than in the morphine-dependent state. When the morphine-withdrawal rats were again given the morphine-admixed food, the osmotic fragility recovered to the morphine-dependent level. The osmotic fragility of phenobarbital-dependent rats was significantly decreased, compared with that of naive rats. On the contrary, in the phenobarbital-withdrawal rats, the osmotic fragility was significantly enhanced, compared with that of the phenobarbital-dependent rats. With re-treatment of phenobarbital-admixed food, the osmotic fragility was recovered to the levels seen in the phenobarbital-dependent rats. Abstinence signs including weight loss, decrease in food and water intake, adrenal hypertrophy etc., were observed during morphine or phenobarbital withdrawal. The effects of food or water deprivation and application of ACTH on the osmotic fragility were then studied and we found that the osmotic fragility was enhanced with these treatments. These results suggest that enhancement of osmotic fragility during withdrawal of these drugs is partly influenced by these treatments.

Adrenal Glands↗
PubMed1982

Method of determining the osmotic fragility curves of erythrocytes in birds.

The osmotic fragility of erythrocytes in 3 species of birds (Gallus gallus domesticus, Coturnix coturnix japonica, Columba livia) and the rat was determined. The results of this study point to a smaller osmotic fragility. Birds, with elliptical erythrocytes, have a lower osmotic fragility than species with round erythrocytes, like most of the mammals.

Animals↗
PubMed1980

Lineation of the osmotic fragility curve of erythrocytes.

Lineation of the osmotic fragility curve by the method of Detraglia et al (1974) may be performed in most samples from a hospital population. Using the lineation procedure, the osmotic fragility may be tested by only 2 solutions of known osmolarity without any great loss of precision or accuracy. The osmotic fragility curve may be described by 2 values: C50 = the concentration at which 50% of the erythrocytes are haemolyzed and C50--C80 = the decrease in concentration raising the fraction of haemolysis from 0.50 to 0.80.

Erythrocytes↗
PubMed2003

Cord blood red cell osmotic fragility: a comparison between preterm and full-term newborn infants.

BACKGROUND: The osmotic fragility of red blood cells reflects their membrane ability to maintain structural integrity. The osmolality at which the cells lyse is related to their shape, deformability, surface area/volume ratio and intrinsic membrane properties. In cord blood, there may be differences between premature and term infants, and be influenced by maternal medication and other factors. There have been no definitive findings on possible differences between preterm and full-term infant osmotic fragility. AIMS: To determine if cord blood erythrocyte osmotic fragility differs between premature and full-term newborn infants, using two parallel techniques. PATIENTS AND METHODS: Cord blood samples were obtained from preterm singletons (N=11), preterm multiple births (N=10), full-term infants (N=24), as well as adults (N=22), for comparison. An osmotic fragility test was used to determine the NaCl concentration at which 20%, 50% and 80% of hemolysis occurred using individual logistic curves. A glycerol lysis test determined the time needed to lyse 50% of red blood cells. RESULTS: Cord blood red cells of multiple birth premature infants were more hemolysis-resistant than erythrocytes from full-term infants or adults. Another index of osmotic fragility, the difference in NaCl concentration for 80% and 20% red cell hemolysis showed that premature infants had greater differences than full-term infants or adults. Glycerol lysis time revealed that both preterm and full-term infants had an erythrocyte subpopulation that took longer than adult blood to attain 50% hemolysis. Correlation between both tests was very significant (r=-0.603, P<0.0001, N=67). CONCLUSIONS: This study shows that erythrocytes of premature infants, although, in average, less osmotically fragile than those of healthy full-term infants, contain a more hemolysis-susceptible cell subpopulation.

Adult↗
PubMed1984

Increased osmotic fragility of erythrocytes in essential hypertension.

The correlation between hypertension and the osmotic fragility of erythrocytes was examined. High osmotic fragility of erythrocytes was observed in patients with essential hypertension and normotensive subjects with family history of hypertension, compared with normotensive controls without family history of hypertension. In patients with secondary hypertension, the osmotic fragility of erythrocytes was not significantly different from that of normotensive controls without family history of hypertension. The membrane fragility had no correlation with the level of blood pressure or dietary salt intake. Thus, the osmotic fragility of erythrocytes might reflect functional or structural abnormalities of cell membranes, and could be one of the genetic markers of the hypertensive predisposition.

Adult↗
PubMed1985

Lack of relation between secondary hyperparathyroidism and red blood cell osmotic fragility in chronic renal failure.

The possible relationship between red blood cell (RBC) osmotic fragility and secondary hyperparathyroidism (HPT) in chronic renal failure was examined in 23 uremic patients on conservative therapy and in 42 patients on maintenance hemodialysis. Secondary HPT was evaluated by means of serum biochemistry (parathyroid hormone, calcium, phosphorus, and alkaline phosphatase) and radiographic examinations (X-ray films of the hand skeleton). This study showed increased RBC osmotic fragility in uremic patients when compared with controls, with no difference between those on conservative therapy and those on maintenance hemodialysis. No correlation between RBC osmotic fragility and the hematochemical changes associated with secondary HPT was found. No difference in RBC osmotic fragility was observed with regard to the activity (alkaline phosphatase) and the severity (X-ray findings) of secondary HPT. Effective treatment of secondary HPT by either pharmacological means (1,25-dihydroxycholecalciferol) or surgical removal was not associated with consequent improvement in RBC osmotic fragility. It is concluded that secondary HPT is probably not a major factor influencing RBC osmotic fragility in chronic renal failure.

Adult↗
PubMed1998

Red blood cell osmotic fragility in chronically hemodialyzed patients.

Chronic renal failure induces anemia and a short erythrocyte life span. Red blood cell (RBC) osmotic fragility is the resistance of RBC hemolysis to osmotic changes that is used to evaluate RBC friability. To find the cause of shortened red cell survival in uremic patients, we evaluated the RBC osmotic fragility in 57 chronic hemodialyzed patients. Each patient had received 12 h of dialysis per week continuously prior to being enrolled in the study. Nineteen healthy volunteers served as a control group. Biochemistry, hemoglobin, electrolyte, osmolarity, beta2-microglobulin, and intact parathyroid hormone were examined before and after the dialysis session. To evaluate the osmotic fragility of RBC, blood samples were collected in heparinized test tubes. Fifty microliters of the RBC of each individual was then incubated in solutions containing a series of various concentrations of NaCl ranging from 0 to 0.6%. The concentration of NaCl at which 50% of RBCs were lysed was considered the median osmotic fragility (MOF). The results showed that the MOF was significantly greater in hemodialyzed patients before dialysis than in the control group (0.41 +/- 0.03 vs. 0.39 +/- 0.02%). The osmotic resistance to hemolysis was also recorded after dialysis (MOF 0.38 +/- 0.03%). Correlation analysis showed that the MOF was significantly correlated with urea nitrogen, serum osmolarity, and intact parathyroid hormone level. In addition, the osmotic fragility was higher in patients who had a predialysis intact parathyroid hormone level > 100 pg/dl. In conclusion, hemodialysis can improve the osmotic fragility. The mechanism underlying this improvement may be the removal of low molecular weight uremic toxins, resulting in normalization of serum osmolarity. Our results indicate that parathyroid hormone is probably a major factor influencing RBC osmotic fragility in chronic renal failure.

Adolescent↗