Mean Corpuscular Fragility Research Articles

Studies on correlations among parasitaemia and some hemolytic indices in two tropical diseases (theileriosis and anaplasmosis) in Fars province of Iran

This study was carried out in two observational clinical studies. Study 1 comprised 50 adult crossbred cattle naturally infected by Theileria annulata. Infected animals were divided into 4 subgroups with different parasitaemia (<1%, 1-3%, 3-5% and >5%). Study 2 comprised 20 adult crossbred cattle naturally infected by Anaplasma marginale. Infected animals were divided into 3 subgroups with different parasitaemia (<10%, 10-20% and 20-30%). In study 1, a significant negative correlation (P<0.001) was observed between parasitaemia and superoxide dismutase (SOD). Positive correlations (P<0.001) were observed between parasitaemia and lactate dehydrogenase (LDH) and mean corpuscular fragility (MCF). In study 2 positive correlations (P<0.05) were observed among parasitaemia and MCF and LDH activity. SOD activity had a negative correlation with parasitaemia in cattle with parasitaemia lower than 10% but no significant correlation (P>0.05) was observed between SOD activity and parasitaemia in cattle with 10-20 and 20-30% parasitaemia. In comparison of both studies we came to the conclusion that in theileriosis as the severity of disease increased the anaemia, MCF and LDH activity increased and SOD activity decreased at any parasitaemia, but in anaplasmosis the anaemia, MCF and LDH activity increased at any parasitaemia but SOD activity decreased only in early but not in advanced stages of disease.

Effects of aqueous extracts of &lt;i&gt;Zanthoxylum macrophylla&lt;/i&gt; roots on membrane stability of human erythrocytes of different genotypes

The effects of aqueous extract of Zanthoxylum macrophylla (formerly Fagara xanthoxyloides) roots on the membrane stabilities of human erythrocyte from HbAA, HbAS and HbSS blood were investigated. The determination of mean corpuscular fragility (MCF), which is the concentration of saline causing 50% haemolysis of the erythrocytes, showed that the aqueous plant extract increased the MCF values of the various erythrocytes. There was no significant difference (p>0.05) between the MCF values of HbAA and HbAS erythrocytes. However, significant difference (p

Effects of 2.45 GHz Radiofrequency Radiation Exposures on Normal and Sickle Erythrocytes

Twenty subjects were used for the study, ten adult sickle cell and ten adult non-sickle cell patients. Blood samples were collected for analysis before and after being irradiated with a 2.45 GHz radiofrequency source. The osmotic fragility of the red blood cells, the packed cell volume and percentage haemolysis for irreversibly sickled cells and non-sickle cells were determined, and the results compared. It was discovered that osmotic fragility of sickle cell subjects was much higher than that of non-sickle cell subjects. The mean corpuscular fragility of sickle cells observed was less than that of non–sickle cells. The value at Complete Lyses for non-sickle cells before irradiation HbAAb was 0.22 ± 0.01% and after HbAAa, it was 0.23 ± 0.02% with a p-value The PCV values for the HbAAb sample ranged from 37.50 to 55.49% with a mean (± SEM) of 44.93 ± 0.90%. The range for the HbAAa was from 26.02 to 34.12% giving a mean of 30.12 ± 0.20% (with p KEY WORDS: Radiofrequency radiation, Sickle cells, Non-sickle cells, Osmotic fragility. Nig. Jnl Health & Biomed. Sciences Vol.3(1) 2004: 56-59

In vitro studies regarding the feasibility of bovine erythrocyte xenotransfusion

Pigs are considered the most likely source of organs and tissues should the barriers to xenotransplantation be overcome. The use of animal blood for transfusion, xenotransfusion, would have advantages over blood from random human donors with respect to supply and infection control. Large animals such as cows would be more suitable than pigs for blood donation because of easier venous access and large volume phlebotomy. Blood from 12 Holstein cows was typed and then tested for hemagglutination assay (HA), complement mediated lysis (CML), human IgM and IgG antibody binding, anti-human globulin augmented clinical cross-match and osmotic fragility with normal human serum. Results were compared with porcine erythrocytes (pRBC) and with human type O controls (hRBC). The frequency of ultra-low xenoantigen expressors was tested in a larger herd of various breeds using HA and CML. Median HA and CML titers were one of six (no HA-one of 64) and one of 26 (no CML-one of 64), respectively for bovine erythrocytes (bRBC). Hemagglutination titer was significantly higher for pRBC at one of 170 (one of four-one of 1024). HA and CML were lowest with bovine blood group J. Repeated HA and CML were negative with bRBC from one cow that also tested negative by anti-human globulin augmented cross-match with seven of nine random human sera representing the different blood groups. However, flow cytometry showed that bRBC from all cows bound human IgM and IgG. IgM mean channel fluorescence (MCF) was positively correlated with HA titer. The mean corpuscular fragility of pRBC, bRBC, and hRBC was 0.56, 0.48 and 0.41%, respectively. The frequency of HA-negative and CML-negative cows were 20 and 35%, respectively in herds of 49 animals. Bovine RBC elicit variable in vitro responses from human serum but these are uniformly much less than those seen with pRBC. Bovine RBC is more robust than pRBC. These characteristics including the potential ease and volume of blood collection make the cow a more suitable blood donor than the pig.

Haematological changes in west African dwarf goats following haemorrhage.

Changes in haematological parameters were determined in West African Dwarf goats subjected to a 30% haemorrhage. Analyses were made before and at the end of bleeding and at 1, 4 and 24 h after haemorrhage. Significant decreases in the red blood cell count, packed cell volume and haemoglobin concentration, which are reportedly due to haemodilution by interstitial fluid were found after haemorrhage. Although the mean corpuscular volume remained normal, the mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration and erythrocyte osmotic fragility decreased significantly 24 h post-haemorrhage. The total white blood cell count increased significantly 4 or 24 h after haemorrhage due to increases in the neutrophil and eosinophil counts. However, the monocyte, basophil and lymphocyte counts were unaltered.

Genetic and Nongenetic Effects on Erythrocyte Osmotic Fragility in Lactating Holstein Cows and Its Association with Yield Traits

Blood samples from 262 lactating Holstein cows were analyzed to determine the resistance of erythrocytes to hypotonic NaCl solutions. The animal model contained stage of lactation, herd, parity, and season as fixed effects, milk yield as a covariate, and 520 random animal effects.A derivate-free algorithm of REML procedure was applied for estimation and prediction. The results suggested higher hemolysis rates and mean corpuscular fragility in first than in later lactations and decreased erythrocyte fragility in cows in late lactation. A negative linear regression of percentage of hemolysis on weekly milk yield was significant. Heritability estimates were .58±.14 for hemolysis rate at 111mM NaCl and .47±.18 for mean corpuscular fragility. Estimates for hemolysis rates decreased with increasing osmotic fragility at lower NaCl concentrations. Phenotypic correlations between erythrocyte fragility traits and 305-d milk, fat, and protein yields were all negative and low. Moderately negative genetic correlations between red blood cell osmotic fragility and fat yield and fat percentage and slightly positive genetic correlations between red blood cell osmotic fragility and protein yield and protein percentage suggested possible alterations in erythrocyte membrane stability if milk component traits were targets for genetic selection.

Toxicological screening models: Drug-induced oxidative hemolysis

In an attempt to obtain a simple screening system for the assessment of toxic-hemolytic effects of chemical substances, a battery of hematological tests was used. Phenacetin served as reference substance. The drug caused reversible formation of methemoglobin and Heinz bodies and an increase in peripheral reticulocytes after 2 and 4 weeks of treatment. Furthermore, an increase in the mean corpuscular volume of red blood cells (RBC) and the volume of RBC ghosts in hypotonic solutions, and a decrease of the mean corpuscular fragility was observed. The latter changes are considered to be a consequence of regenerative RBC compensation rather than due to structural membrane alteration caused by the drug. The results suggest that only a combination of several hematological tests can provide comprehensive information about the hemolytic potential of chemical substances, and that for screening purposes small numbers of animals are often sufficient.

Toxic Effects and Changes of Blood Components by Photodynamic Action Induced by Pheophorbide-a in Rats

In order to clarify the effects of pheophorbide-a, a Chlorella-derived substance with photodynamic activity, the substance was administered orally to rats and on the following day they were irradiated with 20, 000 lux of visible light. The toxic effects on these animals were observed, and analysis of blood components and of the resistance of erythrocytes was performed. The results obtained were as follows:1) Redness was frequently observed on the skin at the auricle and the tail, but scarcely any edema was observed at the occipital and the dorsal positions.2) LD50 of pheophorbide-a was reduced as the irradiation time with visible light was increased.3) Toxicity of pheophorbide-a to rats no longer seen by the 4th day after administration, so this substance might be relatively quickly excreted or decomposed.4) The number of erythrocytes, levels of hemoglobin concentration and hematocrit were increased in the experimental animals. It was also observed that the percentage of rod-shaped nuclear neutrophilic leukocytes in the leukocyte population increased (p<0.05) and that of lymphocytes decreased significantly (p<0.05).5) Among serum electrolytes, no significant differences in the levels of calcium and inorganic phosphorus were recognized between the animals of the experimental group and the control group. However, the sodium level of the experimental group showed a significant decrease and the potassium level showed a marked increase as compared with those of the control group.6) There were no significant differences in serum bilirubin content, serum protein fractions and lipoperoxidase level between these two groups.7) Among serum enzymes, no differences in the levels of GOT, GPT, LDH and Al-P were found between these groups, but the level of CPK of the experimental group was markedly increased compared with that of the control group.8) No difference of mean corpuscular fragility of erythrocytes was recognized between these two groups.

ERYTHROCYTE FRAGILITY IN "DOUBLE-MUSCLED" CATTLE

Osmotic fragility of erythrocytes was determined on heparinized whole blood, sampled from a group of 95 cattle consisting of 73 normal animals from three breed groups and 22 animals showing varying degrees of the double-muscling (DM) trait. Four age groups and two sex groups were sampled from each breed group. Mean corpuscular fragility (MCF) values (the NaCl equivalence producing 50% hemolysis) were interpolated from a fragility curve derived for each animal. The DM breed group had significantly increased erythrocyte fragility as compared to the other breed groups. As animal age increased, the fragility of the erythrocytes was significantly decreased. Sex did not appear to influence erythrocyte fragility. Erythrocyte fragility was also related to the degree of phenotypic expression of the DM trait. Phenotypically extreme DM cattle had increased erythrocyte fragility as compared to phenotypically moderate- to normal-muscled animals of the DM group. Erythrocyte fragility in two of the other breed groups overlapped into the erythrocyte fragility range of the phenotypically moderate- to normal-muscled animals of the DM group, while the remaining breed group showed a decreased erythrocyte fragility. This overlapping provides adequate grounds for the rejection of the erythrocyte osmotic fragility test used in this study as a means of unequivocal identification of DM carriers in cattle. Despite the rejection of this test as a means of carrier detection, the suggestion that DM cattle may have a "generalized membrane defect" is still considered valid.

A computerized method for the determination of the osmotic fragility curve of erythrocytes

A computerized and precise method for the determination of the osmotic fragility curve of erythrocytes was developed. The pH and the temperature, the most important factors for the osmotic hemolysis, were controlled with an accuracy of 7.40 ± 0.01 and 25.0 ± 0.2°C, respectively. The method required an extremely minute amount of blood (about 5 μl). The fragility curve represented by the cumulative and first derivative curves as a function of salt concentration had excellent reproducibility for the mean corpuscular fragility and the slope of the fragility curve. The method was applied to erythrocytes treated with glutaraldehyde and to those with the various contents of cholesterol in the membrane.

The hypotonic fragility of some fish erythrocytes

Osmotic fragilities of red blood cells of three freshwater fish species,Ophicephalus punctatus (Bloch),O. striatus (Bloch), andClarias batrachus (L.) were studied under standard conditions in hypotonic solutions of sodium chloride. The fragility curves of the fishes were found to be of normal sigmoid type similar to those of marine fishes and mammalian erythrocytes. The differences between the mean corpuscular fragility (MCF) values among the species investigated were found to be statistically significant, while the standard deviations at H50 (50% haemolysis) showed that the MCF values remained consistent with in the species.

Red blood cell osmotic fragility in the Spanish mackerel Scomberomorus maculatus

Red cell osmotic fragility was studied in 50 blood samples of the fish Scomberomorus maculatus (Mitchill). High levels of mean corpuscular fragility were found and hypotheses are presented to explain this phenomenon.

The osmotic fragility of some fish erythrocytes in hypotonic saline

1. 1. Osmotic fragility curves of erythrocytes from eleven species of marine teleosts from the Gulf of Mexico are of the normal sigmoid type. 2. 2. The mean corpuscular fragility value is generally consistent within a species but varies widely among the different species. 3. 3. Two species of gars, Lepidosteus osseus and L. productus, have erythrocytes which are resistant to hemolysis in hypotonic sodium chloride solutions.