Search results for "erythrocytes"

Red blood cell sodium and potassium after hydrochlorothiazide.

1981

In six of seven healthy males 6 days of hydrochlorothiazide (HCT), 50 mg twice daily, without potassium supplements resulted in a rise in red blood cell (RBC) sodium concentration. Serum potassium concentration fell in all subjects. Four days after discontinuing HCT, intracellular sodium and extracellular potassium concentrations had normalized. Throughout the evaluation period the course of mean relative intracellular sodium was almost a mirror image of mean relative extracellular potassium. Thus, either the decline of serum potassium or of HCT (because of its inhibitory effect on Na-K-ATPase activity) might have diminished Na-K-ATPase–dependent active RBC sodium efflux with a resultant ri…

Erythrocyte agglutinins in the blood of certain Ascidians

1975

Plasma from Ciona intestinalis, Phallusia mamillata and Ascidia malaca possess hemagglutinin for a variety of erythrocytes. Results obtained by physical and chemical treatments suggest that hemagglutinin for Phallusia mamillata and Ascidia malaca may be a protein or a protein-like substance.

Effects of hydrocortisone on binding of IgG or C3b-coated erythrocytes to human monocytes and polymorphonuclear leucocytes.

1979

In vivo investigations on microcirculatory disturbances induced by crenated erythrocytes following norepinephrine application

1974

Using a special apparatus for high resolution cinephotomicrography, which allows simultaneous observation and recording of microcirculatory changes, alterations in blood flow patterns and in red cell shape during norepinephrine acting have been studied. Under physiological conditions, and during slowing of capillary blood flow due to gradual removing of 20–25% of the circulating blood volume, the normal red cells are extremely deformable while passing through mesenteric capillaries. After application of norepinephrine a general arteriolar constrictive response in the bowel wall occurs, causing a further slowing of the capillary blood flow in the mesentery. Under these circumstances the eryt…

Cell cooperation in coelomocyte cytotoxic activity of Paracentrotus lividus coelomocytes

2007

The coelomic fluid from the sea urchin Paracentrotus lividus contains several coelomocyte types including amoebocytes and uncoloured spherulocytes involved in immune defences. In the present paper, we show a Ca(2+)-dependent cytotoxic activity for the unfractionated coelomocytes assayed in vitro, with rabbit erythrocytes and the K562 tumour cell line. In a plaque-forming assay, whole coelomocyte preparations as well as density gradient separated coelomocyte populations revealed that cell populations enriched in uncoloured spherulocytes, exerted high cytotoxic activity by releasing lysins in the presence of amoebocytes. This cooperative effect could be dependent on soluble factors released b…

Extracorporeal circulation activates endothelial nitric oxide synthase in erythrocytes.

2007

Background Extracorporeal circulation used in cardiopulmonary bypass and hemodialysis is often associated with severe hypotension, which is an important predictor for mortality and morbidity. One pathophysiological hypothesis includes nitric oxide (NO) generation. Recently, a functional NO synthase (endothelial type NO synthase [eNOS]), was found to be expressed in human red blood cells. However, to date, activation of red blood cell eNOS has not been shown. We hypothesized that eNOS in circulating red blood cells might be activated during extracorporeal circulation and thus contribute to hypotension through vasodilation upon NO release. Methods We collected blood samples from 28 patients e…

ATR-FTIR spectroscopy as a quality control system for monitoring the storage of blood products

2021

Blood screening is a fundamental part of disease diagnosis and monitoring health. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy offers an innovative solution to streamlining the process, especially for multianalyte detection in aqueous samples. However, samples always undergo a storage phase before they are processed for testing and blood transfusion. In this study, we investigated the effect of standard storage procedures on the macromolecular composition of whole blood, and plasma collected in blood tubes for diagnostic purposes and initial screening of blood products. Periphery blood samples were collected from 10 volunteers and then stored for 14 days a…

Regulatory effects of polyamines on membrane-bound acetylcholinesterase

1974

The effects of putrescene, spermidine and spermine on membrane-bound acetylcholinesterase from human erythrocyte ‘ghosts’ and the solubilized enzyme of the electric organ of the electric eel were studied by kinetic methods. Measurements were made by using a photometric method which made it possible to record the enzyme reaction in the steady-state phase. Substrate-concentration-dependent activation and inhibition of acetylcholinesterase by polyamines is similar to that by Na+, K+, Ca2+, Mg2+ and certain quaternary and bisquaternary amines. The kinetics suggest an allosteric reaction mechanism. On the basis of the kinetic results a role for the polyamines as modulators of synaptic acetylchol…

Kinetics of streptolysin O self-assembly.

1995

Streptolysin O is a member of a family of membrane-damaging toxins that bind to cell membranes containing cholesterol and then polymerize to form large pores. We have examined the kinetics of toxin action using 125I-labelled streptolysin O. Binding of toxin monomers to membranes displays first-order kinetics and is reversible; the rate of desorption from red cells shows a marked dependence on temperature. To study oligomerization, toxin was bound to erythrocytes at 0 degrees C. Oligomer formation was then triggered by a sudden temperature shift and stopped by solubilization of membranes with deoxycholate. While at moderately high streptolysin O concentrations oligomerization behaves as a re…

Transcription- and apoptosis-dependent long-range distribution of tight DNA-protein complexes in the chicken alpha-globin gene.

2008

The proteins tightly bound to DNA (TBP) are a group of proteins that remain attached to DNA with covalent or noncovalent bonds after its deproteinization, and have been hypothesized to be involved in regulation of gene expression. To investigate this question further, oligonucleotide DNA arrays were used to determine the distribution of tightly bound proteins along a 100-kb DNA fragment surrounding the chicken alpha-globin gene domain in DNA from chicken erythrocytes, liver, and AEV-transformed HD3 (erythroblast) cells in different physiological conditions. DNA was fractionated into TBP-free (F) and TBP-enriched (R) fractions by separation on nitrocellulose, and these fractions were used as…