Showing papers on "Red blood cell published in 1976"
TL;DR: The results indicate that active genes are probably associated with histones in a subunit conformation in which the associated DNA is particularly sensitive to digestion by deoxyribonuclease I.
Abstract: Ten percent digestion of isolated nuclei by pancreatic deoxyribonuclease I preferentially removes globin DNA sequences from nuclei obtained from chick red blood cells but not from nuclei obtained from fibroblasts, from brain, or from a population of red blood cell precursors. Moreover, the nontranscribed ovalbumin sequences in nuclei isolated from red blood cells and fibroblasts are retained after mild deoxyribonuclease I digestion. This suggests that active genes are preferentially digested by deoxyribonuclease I. In contrast, treatment of red cell nuclei with staphylococcal nuclease results in no preferential digestion of active globin genes. When the 11S monomers obtained after staphylococcal nuclease digestion of nuclei are then digested with deoxyribonuclease I, the active globin genes are again preferentially digested. The results indicate that active genes are probably associated with histones in a subunit conformation in which the associated DNA is particularly sensitive to digestion by deoxyribonuclease I.
1,612 citations
TL;DR: The results of these studies indicate that the sulfate self-exchange flux is mediated by a “two-site transport mechanism” consisting either of a mobile carrier or a two-site pore and the mutual competition between sulfate and chloride point to a common transport system for both anion species.
Abstract: The sulfate and the chloride self-exchange fluxes were determined by measuring the rate of the tracer efflux from radioactively labeled human red blood cells and red blood cell ghosts. The concentration dependence and the pH-dependence of the sulfate self-exchange flux were studied. In addition, the effects of some monovalent and divalent anions on the sulfate and the chloride self-exchange fluxes were investigated.
119 citations
TL;DR: It is concluded that these morphological differences are due to different mechanisms of polyene-sterol interactions in which the different size of the macrolide ring in the antibiotic structure may be involved.
107 citations
TL;DR: The identification of these two types of binding sites allows phloretin effects on protein-mediated transport processes to be distinguished from effects on the lipid region of the membrane.
Abstract: Phloretin binding to red blood cell components has been characterized at pH6, where binding and inhibitory potency are maximal. Binding to intact red cells and to purified hemoglobin are nonsaturated processes approximately equal in magnitude, which strongly suggests that most of the red cell binding may be ascribed to hemoglobin. This conclusion is supported by the fact that homoglobin-free red cell ghosts can bind only 10% as much phloretin as an equivalent number of red cells. The permeability of the red cell membrane to phloretin has been determined by a direct measurement at the time-course of the phloretin uptake. At a 2% hematocrit, the half time for phloretin uptake is 8.7s, corresponding to a permeability coefficient of 2 x 10(-4) cm/s. The concentration dependence of the binding to ghosts reveals two saturable components. Phloretin binds with high affinity (K diss = 1.5 muM) to about 2.5 x 10(6) sites per cell; it also binds with lower affinity (Kdiss = 54 muM) to a second (5.5 x 10(7) per cell) set of sites. In sonicated total lipid extracts of red cell ghosts, phloretin binding consists of a single, saturable component. Its affinity and total number of sites are not significantly different from those of the low affinity binding process in ghosts. No high affinity binding of phloretin is exhibited by the red cell lipid extracts. Therefore, the high affinity phloretin binding sites are related to membrane proteins, and the low affinity sites result from phloretin binding to lipid. The identification of these two types of binding sites allows phloretin effects on protein-mediated transport processes to be distinguished from effects on the lipid region of the membrane.
92 citations
TL;DR: The clinical use of red blood cell polyamines as an indicator of the activity of the bone marrow in anemic states is suggested because of highly significant statistical differences between young and old red blood cells for putrescine, spermidine and spermine.
77 citations
TL;DR: Red blood cells from 7 out of 13 patients with chronic uremia were found to have increased intracellular concentrations of sodium associated with a reversible inhibition of ouabain-sensitive Na efflux when incubated in control plasma, and enzyme kinetics revealed a significant increase in KmATP values for this enzyme in uremic RBCs.
Abstract: Red blood cells from 7 out of 13 patients with chronic uremia were found to have increased intracellular concentrations of sodium associated with a reversible inhibition of ouabain-sensitive Na efflux when incubated in control plasma. Although mean Na-K-ATPase activity of RBC hemoly sates was only moderately decreased (21.8 ± 1.5 vs. 26.5 ± 1.8 nmol Pi/mg protein/h), enzyme kinetics revealed a significant increase in Kmatp values for this enzyme in uremic RBCs (1.01 ± 0.1 vs. 0.58 ± 0.03; p
72 citations
TL;DR: The applicability to red blood cells of two widely used methods for spectrophotometric assay of superoxide dismutase activity has been tested, in view of the demand for routine screening of the level of this enzyme in various circumstances of hematological interest.
65 citations
TL;DR: Pure venom from the acontial nematocysts of the sea anemone Aiptasia pallida exhibited phospholipase A (phosphatide acyl-hydrolase; EC 3.1.4) activity on a mixture of freeospholipids.
61 citations
TL;DR: The hematology of adult winter flounder was investigated weekly from December 1972 through January 1974, and the constituents of the blood associated with stress response and infections, i.e., the total white blood cells, were at their yearly peak.
Abstract: The hematology of adult winter flounder was investigated weekly from December 1972 through January 1974. The following parameters revealed statistically demonstrable variation between seasons: hemoglobin (Hb), blood oxygen capacity (CBO2), hematocrit (Hct), red blood cell number (RBC), immature red blood cell number, mean corpuscular volume, mean corpuscular hemoglobin, leukocytes, lymphocytes, thrombocytes, neutrophils, condition factor, and apparent health. The blood constituents concerned with metabolic processes such as oxygen transport, e.g., Hb, Hct, CBO2, and RBC, were lowest during late winter and early spring when winter flounder fast and undergo reproduction activity. At this time the constituents of the blood associated with stress response and infections, i.e., the total white blood cells, were at their yearly peak. The leukocyte count declined during the summer and remained low throughout the rest of the year. Conversely, the Hct, HB, CBO2, and RBC increased during the summer and rem...
50 citations
TL;DR: The biochemical characteristics of soluble catechol‐O‐methyltransferase (COMT) activity in rat erythrocytes were compared with the properties of the soluble enzyme in rat liver, heart, and brain to measure COMT by a procedure that avoided artifacts of some other assay procedures including inhibition of the enzyme by endogenous calcium.
Abstract: The biochemical characteristics of soluble catechol-O-methyltransferase (COMT) activity in rat erythrocytes were compared with the properties of the soluble enzyme in rat liver, heart, and brain. COMT was measured by a procedure that avoided artifacts of some other assay procedures including inhibition of the enzyme by endogenous calcium. After the removal of calcium from the reaction mixture the apparent Michaelis-Menten constants for the two cosubstrates of the COMT reaction, S-adenosyl-1-methionine (SAM) and 3,4-dihydroxybenzoic acid (DBA), were similar in tissue preparations of rat liver, brain, heart and blood. The apparent Km values for the four tissues ranged from 5.7 to 6.7 x 10(-6) M and from 0.9-1.4 x 10(-4) M for SAM and DBA, respectively. The optimal pH and the optimal concentration of magnesium for the assay of red blood cell COMT were also similar to those for the enzyme in the three other rat tissues. After the removal of endogenous calcium, COMT activity in all four tissues was inhibited by the addition of calcium, and the [CaCl2] necessary to inhibit the enzyme activity 50% was 3-5 x 10(-4) M in all cases. The relative activities of COMT in the rat heart, brain, erythrocyte, and liver when expressed per g tissue or per ml of packed red blood cells were 1 to 1.15 to 1.58 to 140, respectively.
48 citations
TL;DR: Experimental results indicate that this cross-linking is caused by direct photooxidation of membrane proteins, and that spectrin and the bands 2.1, 2.2, 3.3 and 6 are most susceptible and that band 3 is least susceptible to this cross thelinking reaction.
TL;DR: The ultrastructural distribution pattern and antigen site density of the major Rh antigens on red blood cell ghosts sensitized with IgG Rh antibodies were determined using electron microscopy and ferritin conjugated rabbit anti‐human IgG to indicate that the Rh antigen complex is associated with a single membrane component.
Journal Article•
TL;DR: Although the Bohr factor did not show a clear relation to age, the oxygen affinity and the oxygen capacity tended to increase with the lapse of days, and the power of heme-to-heme interaction, to decrease with age, implying that there is a respiratory adaptation of embryos during development.
Abstract: Oxygen dissociation curves for blood in the chorioallantoic capillary of chicken embryos were determined using a microphotometric apparatus made for measuring the reaction velocity of a red blood cell with oxygen and carbon monoxide. The modified Hill's equations expressing the dissociation curve during development were calculated by two methods. P50's at pH of 7.4 were found to be 60.0, 54.4, 46.2, 33.1, and 28.6 mmHg for 10, 12, 14, 16 and 18 days of incubation, respectively. Although the Bohr factor did not show a clear relation to age, the oxygen affinity and the oxygen capacity tended to increase with the lapse of days, and the power of heme-to-heme interaction, to decrease with age. The findings imply that there is a respiratory adaptation of embryos during development.
TL;DR: Bisphosphoglycerate synthase from horse red cells has been purified to apparent homogeneity by a simple and efficient new procedure incorporating chromatography on a column of Sepharose 4B derivatized with blue dextran.
Journal Article•
TL;DR: The impaired osmotic fragility of thalassemic erythrocytes almost returned to normal following administration of vitamin E, a potent antioxidant, in a daily dose of 750 IU for three to six months.
Abstract: Red blood cell membranes from patients with beta-thalassemia major and intermedia had an average of 25% less sialic acids, and a 50% decrease in titratable SH groups, as compared with normal controls. Membranes from 12 of 13 splenectomized patients were less dense and could be clearly distinguished from normal membranes on a sucrose linear density gradient, indicating a change in lipid-to-protein ratio. The impaired osmotic fragility of thalassemic erythrocytes almost returned to normal following administration of vitamin E, a potent antioxidant, in a daily dose of 750 IU for three to six months. These observations provide more evidence that membrane properties of thalassemic red blood cells differ from those of normal erythrocytes, the difference being due, in part, to increased oxidative stress.
TL;DR: The difference in the electrokinetic properties of normal and sickling red blood cells in this system may be attributed, in part, to a variation in the polyamine content of the two types of erythrocytes.
TL;DR: The β-bungarotoxin is an enzyme which can bind specifically with high affinity to cell membranes, which is comparable to the concentrations previously shown to inhibit mitochondrial function.
TL;DR: To achieve the most efficient washing, three principles must be utilized: concentration of the red blood cells to hematocrit values of 90 per cent, prior to washing or freezing, and on‐line dilution should be achieved in the washing systems that use continuous‐flow centrifugation.
TL;DR: Measurements of the steady oxygen permeation rate through films of nonreactive and reactive dispersions, including suspensions of red blood cells, show substantial facilitation of oxygen transport occurred when oxyhemoglobin gradients were steep, but both the data and the theory exhibited considerably less facilitation than would be suggested by an equilibrium analysis.
Abstract: Experimental measurements were made of the steady oxygen permeation rate through films of nonreactive and reactive dispersions, including suspensions of red blood cells. The data compare well with a theoretical analysis which incorporates a one-step reversible reaction within the dispersed phase. In the absence of reaction, the red cell permeability could be treated as that of a concentrated hemoglobin solution. For reactive suspensions of red cells or water-in-oil emulsions containing hemoglobin at 25°C, substantial facilitation of oxygen transport occurred when oxyhemoglobin gradients were steep, but both the data and the theory exhibited considerably less facilitation than would be suggested by an equilibrium analysis.
TL;DR: The lipid extracts of normal and Plasmodium knowlesi- infected rhesus erythrocytes and of the parasite itself have been examined for phospholipid composition on an animal-to-animal basis and several differences were apparent.
TL;DR: It was found that haemolysates up to 5 years old could be reliably typed when prepared from washed anticoagulated red blood cells and the Manx population has higher Esterase D 2 gene frequencies than neighbouring populations.
Abstract: Several regional series from Britain and 3 Asian series were typed for the Esterase D polymorphism. It was found that haemolysates up to 5 years old could be reliably typed when prepared from washed anticoagulated red blood cells. Lysates prepared from blood clots do not retain Esterase D activity quite as well. The Manx population has higher Esterase D 2 gene frequencies than neighbouring populations. A Nepalese population exhibits the highest Esterase D 2 gene frequency so far recorded. The other series presented supplement or confirm results already published.
TL;DR: Significant reduction in the activity of the enzymes cholinesterase, catecholamine oxidase, total proteins, albumin, urea and electrolytes were obvious, and returned to normal values after treatment, and the results are discussed in relation to anemia and liver damage that may accompany the syndrome.
TL;DR: Outdated human red blood cells were kept in isotonic salt solution at 37°C and the activity of the Mg-dependent ATPase was assayed to indicate corresponding conformational changes in the membrane.
TL;DR: Results indicate that erythrocytes stored with addition of progesterone have higher ATP levels, less spontaneous lysis, higher osmotic resistance, and higher uptake of methylene blue throughout the time of storage than do cells stored without added progestersone.
Journal Article•
01 Jan 1976
TL;DR: Several comprehensive models of erythropoiesis exist and have been verified by data from mammalians subjected to hypoxia £127 or treated with irradiation or iso-anti-bodies.
Abstract: The fundamental regulatory mechanisms of red blood cell formation which have “been subject to extensive experimental research are nowadays well understood [1, 2]. Thus, numerous attempts have been made to quantitative investigation of erythropoiesis by means of mathematical models. A number of models have been developed for single components of the erythropoietic system like the stem cell pool [3, 4, 5], the erythropoietic cells in bone marrow [6, 7, 8] or the erythrocytes in blood [9, 10]. Besides, several comprehensive models of erythropoiesis exist [11, 12, 13]. They have been verified by data from mammalians subjected to hypoxia £127 or treated with irradiation or iso-anti-bodies [11].
TL;DR: Local X-ray irradiation of a transplantable rat tumour in a single dose of 3000 R increased significantly the extracellular space of this tumor as estimated by the plasma-tissue equilibration of 51Cr-EDTA, while the plasma and red blood cell volume after sacrifice by bleeding under ether anaesthesia were unchanged.
Abstract: Local X-ray irradiation of a transplantable rat tumour in a single dose of 3000 R increased significantly the extracellular space of this tumor as estimated by the plasma-tissue equilibration of 51Cr-EDTA, while the plasma and red blood cell volume as estimated with 125I-labelled albumin and 59Fe-labelled erythrocytes after sacrifice by bleeding under ether anaesthesia were unchanged. These results combined signified a decreased cell volume of cells, excluding red blood cells.