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PubMed1997

[Rheologic study of the dissociation reaction of erythrocyte immunologic agglutinates: application to subgroup A erythrocytes].

Red blood cell Agglutinates can be dissociated by providing enough energy which may be supplied by shear stress in a viscometer. In this paper a new technique is proposed to determine dissociation parameters of erythrocyte immunological agglutinates by using a laser backscattering method. Backscattered light intensity increases during the process of agglutinate dissociation when a controlled shear stress in a transparent Couette viscometer is applied. The obtained curves of dissociation can be fitted by an exponential function. A numerical integration of the dissociation curves allows us to obtain a parameter associated to the energy used in the dissociation process. A satisfactory differentiation of erythrocyte sub-groups Al, Az, A,B and Am has been carried out using this technique.

Blood Viscosity↗

PubMed1975

Coenzyme A requirement of malaria parasites: enzymes of coenzyme A biosynthesis in normal duck erythrocytes and erythrocytes infected with Plasmodium lophurae.

Normal duck erythrocytes and erythrocytes infected with Plasmodium lopharae have all of the enzymes for coenzyme A biosynthesis, whereas parasites freed from their host cells have non. Since erythrocytefree cultivation of P. lophurae requires an exogenous source of coenzyme A, this parasite must obtain its coenzyme A entirely from the host cell during infection.

Adenosine Triphosphate↗

PubMed2005

Effects of some antibiotics on activity of glucose-6-phosphate dehydrogenase from human erythrocytes in vitro and effect of isepamicin sulfate on activities of antioxidant enzymes in rat erythrocytes.

The purpose of this study was to investigate effects of some antibiotics on glucose-6-phosphate dehydrogenase (G6PD), antioxidant enzymes, and malondialdehyde (MDA). Initially, for in vitro studies, G6PD was purified from human erythrocyte, 9811-fold in a yield of 42.4% by using ammonium sulfate precipitation and 2',5' ADP-Sepharose 4B affinity gel. The purified enzyme showed a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The effects of four different antibiotics (isepamicin sulfate, meropenem, chloramphenicol, and thiamphenicol glisinat hydrochloride) were investigated on the purified enzyme. K(i) value and type of inhibition were determined by means of Lineweaver-Burk graphs and regression analysis graphs. Isepamicin sulfate inhibited the enzyme activity (I(50) value, 2.1 mM; K(i) value, 1.7 mM), whereas thiamphenicol glisinat hydrochloride activated the G6PD dose dependently. Other drugs showed no inhibition and activation effect. In addition, the effects of isepamicin sulfate on the activities of G6PD, glutathione reductase (GR), superoxide dismutases (SOD), glutathione peroxidase (GPx), catalase (CAT), and glutathione S-transferase (GST) and MDA concentrations were examined in Sprague-Dawley rat erythrocytes in vivo. A marked alteration in the activities of these enzymes and MDA levels may be the result of oxidative stress in the rats receiving isepamicin sulfate.

Adult↗

PubMed2005

Effects of low molecular weight plasma inhibitors of rainbow trout (Oncorhynchus mykiss) on human erythrocyte carbonic anhydrase-II isozyme activity in vitro and rat erythrocytes in vivo.

The effects of low molecular weight plasma inhibitors from rainbow trout (Oncorhynchus mykiss) (RT) were investigated on the carbonic anhydrase enzyme (CA) activities in in vitro human and in in vivo Sprague-Dawley rat erythrocytes. The RT blood was used as extracellular fluid (plasma) source and plasma inhibitors were obtained by dialysis of the plasma. For the in vitro study, human carbonic anhydrase-II (HCA-II) isozyme was obtained by Sepharose 4B-L-tyrosine-sulfanylamide affinity chromatography with an overall purification of about 646-fold. The enzyme (specific activity of 7750 EU/mg protein) was obtained with a yield of 71.1% and SDS-PAGE showed a single band. From in vitro studies, the I50 value for RT plasma inhibitors obtained was 0.37 mg/ml. From in vivo studies on rat erythrocytes, CA activity was significantly inhibited by the inhibitors from the extracellular fluid of RT for up to 3 h (p < 0.05) following intraperitoneal administration.

Animals↗

PubMed1988

Cytoadherence by Plasmodium falciparum-infected erythrocytes is correlated with the expression of a family of variable proteins on infected erythrocytes.

Plasmodium falciparum-infected erythrocytes (IRBCs) adhere specifically to venular endothelium and thereby evade spleen-dependent immune mechanisms. We have investigated the molecular basis of cytoadherence. We report here that the capacity for cytoadherence of IRBCs is correlated with the expression of a family of variable proteins on the surface of IRBCs. Essential to these studies was the use of in vitro techniques for modulating the cytoadherence phenotype of cloned parasites. In initial studies, we found culture-adapted parasites to be poorly cytoadherent or noncytoadherent. To select for cytoadherent parasites, we incubated knobbed IRBCs with C32 melanoma cells and cultured the adherent cells. Repeated rounds of selection produced parasites with increased cytoadherence. To select for noncytoadherent parasites, we cultured the cells that did not adhere to C32 melanoma cells. Cytoadherent IRBCs from two different cloned isolates had large (Mr greater than 2.4 x 10(5) radioiodinatable proteins that differed in size between the isolates but had in common the biochemical properties of trypsin sensitivity and insolubility with Triton X-100. The proteins were not detected with uninfected erythrocytes, indicating that they were parasite determined, nor were they detected with IRBCs containing parasites cultured for many months without selection. With continued selection for the cytoadherent phenotype, additional IRBC surface proteins with larger molecular sizes (Mr 2.9 x 10(5) and 3.2 x 10(5] appeared. A sequence of reversible changes in the cytoadherence phenotype of cloned parasites was accompanied by variation in the molecular size of the IRBC surface protein. Increased cytoadherence was correlated with expression of larger proteins and decreased cytoadherence was correlated with expression of smaller proteins; there was no change in the molecular size of two other parasite proteins associated with the IRBC membrane. The results indicate that the expression of this family of proteins is closely linked to the cytoadherence phenotype of the parasites, suggesting that the members of the protein family have a role in mediating cytoadherence between IRBCs and endothelial cells.

Animals↗

PubMed1994

Reference ranges for erythrocyte pyridoxal 5'-phosphate concentration and the erythrocyte aspartate transaminase stimulation test in lactating mothers and their infants.

We determined reference ranges for erythrocyte pyridoxal 5'-phosphate concentrations (EPLP) and erythrocyte aspartate transaminase basal activities (EASTo) and activation coefficients (alpha EAST) in lactating mothers and infants from data of mothers receiving a vitamin B-6 supplement and infants breast-fed by mothers with adequate vitamin B6 status. The mothers' vitamin B6 status was assessed on the third day postpartum (pp) (n = 91) and at 2 mo (n = 114), 4 mo (n = 117), 6 mo (n = 110), and 9 mo (n = 40) pp and that of the exclusively breast-fed infants at 2 mo (n = 90), 4 mo (n = 106), and 6 mo (n = 99). We also examined 9-mo-old infants (n = 39) who, besides breast milk, had received solids after 6 mo, and 12-mo-old infants (n = 100) who had received solids beginning at 4-6 mo and dairy products at 9 mo. Values indicating deficiency for at least two of the three indexes distinguished the 5-10% of mothers and infants with the lowest vitamin B6 status. The reference ranges for EPLP, EASTo, and alpha EAST for infants and for mothers during the first months of lactation differ from those reported earlier for adults.

Aspartate Aminotransferases↗

PubMedDate not supplied

The effects of ethanol on glucose 6-phosphate dehydrogenase enzyme activity from human erythrocytes in vitro and rat erythrocytes in vivo.

AIMS: The effects of ethanol on erythrocyte glucose 6-phosphate dehydrogenase (G6PD) activity were investigated under in vitro and in vivo conditions. METHODS: For in vitro studies, glucose 6-phosphate dehydrogenase was purified from human erythrocyte and rats were used for in vivo studies. Enzyme activity was determined spectrophotometrically by the Beutler method. RESULTS: The in vitro study showed that the I(50) value was 17 mM for ethanol. In the case of the in vivo study, a 2 ml/kg dose of ethanol significantly inhibited the G6PD activity. The inhibition rate after ethanol administration was 59%, 40% and 6% at 1, 3 and 6 h after, respectively. CONCLUSIONS: The results of this study suggest that ethanol has a significant inhibitory effect on the G6PD activity both in vivo and in vitro.

Animals↗

PubMed1975

Removal of leukocytes from whole blood and erythrocyte suspensions by filtration through cotton wool. V. Results after transfusion of 1,820 units of filtered erythrocytes.

1,820 units of leukocyte- and platelet-poor erythrocyte suspensions were prepared by filtration through cotton wool. On the average more than 98% of the leukocytes and 90-95% of the platelets could be removed. The red cell recovery was 96%. 97% of the units given to polytransfused patients did not cause febrile reactions. Serological follow-up of future transplantation recipients indicated that the immunization may be avoided by using erythrocyte suspensions of fresh, filtered blood.

Antibodies↗

PubMed1979

Expression of T-antigen on polyagglutinable erythrocytes and carcinoma cells: preparation of T-activated erythrocytes, anti-T lectin, anti-T absorbed human serum and purified anti-T antibody.

Recent interest has been revived in the human MN blood group system due to the discovery of the MN precursor substance (T-antigen) on certain malignant, but not benign or normal tissues. Methods for preparing T-activated erythrocytes, anti-T lectin, anti-T absorbed human serum and purified anti-T antibody are described and should be useful not only to the researcher involved in this new line of investigation, but also to the routine blood bank faced with the occasional problem of erythrocyte polyagglitinability.

ABO Blood-Group System↗

PubMed2002

Immunogenicity and protective efficacy of three DNA vaccines encoding pre-erythrocytic- and erythrocytic-stage antigens of Plasmodium cynomolgi in rhesus monkeys.

Although several malaria vaccine candidate antigens have been identified, the most suitable methods for their delivery are still being investigated. In this regard, direct immunization with DNA encoding these vaccine target antigens is an attractive alternative. Here, we have investigated the immune responses to DNA immunization with three major vaccine target antigens: the apical membrane antigen-1 and the 19-kDa C-terminal fragment of merozoite surface protein-1 from the erythrocytic stage, and the thrombospondin-related adhesive protein from the pre-erythrocytic stage of Plasmodium cynomolgi in rhesus monkeys. Antigen-specific antibodies were developed in all the immunized monkeys and peripheral blood mononuclear cells from all immunized monkeys proliferated to different extents upon in vitro stimulation with the corresponding recombinant proteins. The immunized monkeys were challenged with P. cynomolgi sporozoites. All of the immunized animals developed infection but although there was no significant difference between the control and vaccinated animals in terms of pre-patent period, total duration of patency and primary peak parasitemia, the vaccinated animals had significantly lower secondary peak parasitemia than the control animals.

Animals↗

PubMed1976

Chronic haemolytic anaemia in two patients heterozygous for erythrocyte pyruvate kinase deficiency. Electrofocusing and immunological studies of erythrocyte and liver pyruvate kinase.

Two patients with mild chronic haemolytic anaemia, a mother and her son, were found to be heterozygous for erythrocyte pyruvate kinase deficiency. In the red blood cells the enzymatic activity was reduced by about 50% and the residual PK had normal kinetic properties, stability and electrofocusing pattern. The PK antigen concentration was also decreased by half, so that the ratio of the enzymatic activity to the immunological reactivity (i.e. the molecular specific activity) was normal. In the son's liver PK enzymatic activity was slightly reduced and, above all, an abnormal active form, more anodic than normal PK, was detected by electrofocusing. The propositus's liver PK was also slightly thermo-unstable. It is suggested that the patients were heterozygous for an unstable PK variant which is found in liver, nucleated tissue actively synthesizing proteins, but which disappeared from the erythrocytes because of its unstability.

Adult↗

PubMed1985

Selenium in plasma and erythrocytes in patients with Down's syndrome and healthy controls. Variation in relation to age, sex and glutathione peroxidase activity in erythrocytes.

The mean plasma selenium concentration (P-Se) in 65 patients with Down's syndrome (DS) did not differ from that in 90 healthy controls. The concentration of selenium in the erythrocytes (E-Se) was higher in DS patients than in controls (p less than 0.001). P-Se and E-Se increased progressively with age through childhood in both DS children and controls. The former children, however, started out with higher levels of E-Se and reached adult concentrations earlier (at 7-17 years) than controls (greater than or equal to 18 years). Adult DS patients and controls did not differ in their mean P-Se or E-Se concentration. There was a significant correlation between P-Se and E-Se both in DS patients and in controls. In DS patients each of these two variables was significantly correlated to glutathione peroxidase (GSH-Px) activity in erythrocytes. A sex difference in the DS children, but not in the controls, was observed with regard to P-Se and E-Se levels, these being higher in DS girls during childhood (0-17 years). This was in accordance with an earlier finding of higher GSH-Px activity in DS girls than in DS boys.

Adolescent↗

PubMed1976

Studies on the membrane glycoprotein defect of En(a-) erythrocytes. II. MN antigenic properties of En(a-) erythrocytes.

En(a-) and EnaEn red cells from different sources were studied using biochemical and serological methods. The results suggest that Finnish En(a-) erythrocytes contain only "N" but no M antigenic properties. Data on the members of the English En(a-) family suggest that English En(a-) red cells exhibit a combination of three rare alterations. The English En(a-) individuals are apparently heterozygous for the defects En and Ms, to all appearances, converted to a M ("M") antigen. These extraordinary data are brought to light by investigations on the children of the propositus (G.P. and J.P.), whose red cells are M-N+S-s+"N"+"M"- and M-N+S+s+"N"+"M"+ respectively. Sodium dodecylsulphate polyacrylamide gel electrophoretic results indicate that the MN glycoprotein content is decreased by about 50% in all English S+s+EnaEn red cells, the Ss glycoprotein being normal. G.P. erythrocytes, however, have only about half of the normal MN and Ss glycoprotein content.

Blood Group Antigens↗

PubMed1985

Erythrocyte selenium-75 uptake as a measure of selenium status in weaner sheep, and its relationship to erythrocyte glutathione peroxidase activity.

The relationship between in vitro erythrocyte 75Se uptake (75Se uptake) and erythrocyte glutathione peroxidase (EGSHPx) activity was examined in weaner sheep during periods of selenium depletion and repletion, to determine whether 75Se uptake was better correlated than EGSHPx activity to the development of weaner nutritional myopathy. In the 2 trials conducted, only 3 of 45 Merino wether weaners developed clinical myopathy and histological lesions in skeletal muscles. The 75Se uptake values and EGSHPx activities in these 3 sheep were no different from those in the unaffected sheep. There was a significant negative correlation between 75Se uptake values and EGSHPx activities over the entire period of the trials. It could not be demonstrated that 75Se uptake was any better correlated than EGSHPx activity to the development of nutritional myopathy, and it was concluded that EGSHPx activity indicated selenium status better than 75Se uptake in weaner sheep.

Animals↗

PubMed1975

Interactions between aerolysin, erythrocytes, and erythrocyte membranes.

Aerolysin, a hemolytic and lethal exotoxin of Aeromonas hydrophila, was analyzed for amino acids. Assuming 8 histidine residues/mol, the purified toxic protein has, by summation, a molecular weight of 49,000, a value in agreement with earlier estimates by other methods. Erythrocytes from different animal species differ greatly in sensitivity to aerolysin's lytic action. There is some correlation between sensitivity and phosphatidyl choline content. Erythrocyte membranes of different species bind the toxin, and the efficiency of binding is a function of sensitivity to lysis. Binding is temperature independent, is not dependent upon membrane sialic acid, and is decreased by prior treatment with phospholipase C and proteases. Preparations of aerolysin convert substantial amounts of membrane phosphorus to water-soluble form; the conversion is concentration and temperature dependent. Most of the conversion is attributable to contaminating phospholipase(s) that is separable from the toxin. Aerolysin purified by electrophoresis in polyacrylamide gel retains some phospholipase activity, and this activity may or may not be a contaminant.

Aeromonas↗

PubMed1991

Drosophila to bacteriophage to erythrocyte: the erythrocyte as a model for molecular and membrane aging of terminally differentiated cells.

Senescent cell antigen appears on old cells and marks them for death by initiating the binding of IgG autoantibody and subsequent removal by phagocytes in mammals and other vertebrates. Although the initial studies are done using erythrocytes as a model, senescent cell antigen has been found on all cells examined. Oxidation generates senescent cell antigen in situ. Senescent cell antigen is generated by the modification of an important structural and transport membrane molecule, protein band 3. Band 3 is a ubiquitous protein. It is present in cell, nuclear, Golgi, and mitochondrial membranes. Band 3 is the most heavily used anion exchanger in the human body because of its crucial role in respiration and acid-base balance. Senescent cell antigen has been localized to band 3 residues 538-554 and 812-827, using competitive inhibition studies with synthetic peptides of band 3 to absorb the IgG isolated from senescent erythrocytes and immunoblotting studies. In mammalian brain, band 3 performs the same functions as that of erythroid band 3. These functions are anion transport, ankyrin binding, and generation of senescent cell antigen, an aging antigen that terminates the life of cells. Our results suggest that the transport domain of erythroid and neural band 3 are similar functionally and structural. This supports the hypothesis that the immunological mechanism of maintaining homeostasis is a general physiologic process for removing senescent and damaged cells in mammals and other vertebrates.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed2002

Effects of gentamicin sulfate on enzyme activities of carbonic anhydrase from human erythrocytes in vitro and from rat erythrocytes in vivo.

The effects of gentamicin sulfate on carbonic anhydrase (CA) enzyme activity in in vitro human and in in vivo rat erythrocytes were investigated. For in vitro study, human carbonic anhydrase-I and -II (HCA-I and HCA-II) were purified by affinity-column chromatography, and rats were used for in vivo study. In vivo and in vitro CA enzyme activity was determined colorimetrically using the CO2-hydration method of Wilbur and Anderson as modified by Rickli et al. Gentamicin sulfate (1.98-9.90 mM) showed in vitro inhibitory effects on HCA-I and HCA-II hydratase activity up to a 2 mM concentration, when determined using the C02-hydratase method. Rat erythrocyte CA activity was significantly inhibited for up to 3 h (p<0.001) following intramuscular administration of gentamicin sulfate to Sprague-Dawley rats (3.2 mg/kg body weight). In conclusion, gentamicin sulfate inhibits CA enzyme activity in vivo and at low concentrations in vitro, but activated it at high concentrations (> or = 4 mM) in vitro.

Animals↗

PubMed2000

Selection of Babesia bovis-infected erythrocytes for adhesion to endothelial cells coselects for altered variant erythrocyte surface antigen isoforms.

Sequestration of Babesia bovis-infected erythrocytes (IRBCs) in the host microvasculature is thought to constitute an important mechanism of immune evasion. Since Ig is considered to be important for protection from disease, an in vitro assay of B. bovis sequestration was used to explore the ability of anti-B. bovis Ig to interfere with IRBC cytoadhesion, and to identify IRBC surface Ags acting as endothelial cell receptors. Bovine infection sera reactive with the IRBC surface inhibited and even reversed the binding of IRBCs to bovine brain capillary endothelial cells (BBECs). This activity is at least partially attributable to serum IgG. IgG isolated from inhibitory serum captured the variant erythrocyte surface ag 1 (VESA1) in surface-specific immunoprecipitations of B. bovis-IRBCs. Selection for the cytoadhesive phenotype concurrently selected for antigenic and structural changes in the VESA1 Ag. In addition, the anti-VESA1 mAb, 4D9.1G1, proved capable of effectively inhibiting and reversing binding of adhesive, mAb-reactive parasites to BBECs, and by immunoelectron microscopy localized VESA1 to the external tips of the IRBC membrane knobs. These data are consistent with a link between antigenic variation and cytoadherence in B. bovis and suggest that the VESA1 Ag acts as an endothelial cell ligand on the B. bovis-IRBC.

Animals↗