Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Spherocytes”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1992

Transbilayer asymmetry of pyrene mobility in human spherocytic red cell membranes.

The diffusion-dependent formation of pyrene excimers (excited dimers) was studied in normal and spherocytic red cell membranes. Pyrene emission was alternatively quenched in either bilayer half by non radiative energy transfer to haemoglobin. Pyrene excimer to monomer fluorescence intensity ratio, I'/I, was 0.35 +/- 0.03 (S.E.) in washed red blood cells obtained from normal donors (n = 8) and 0.45 + 0.03 (n = 13) in the corresponding isolated, haemoglobin-free resealed membranes (P less than 0.02). In the spherocytic condition the respective values were 0.28 +/- 0.01 (n = 9) and 0.53 +/- 0.03 (n = 9), P less than 0.001. In contrast to the decrease of I'/I in red cells as compared to isolated membranes, being 22% in normal cells and 47% in spherocytic ones, haemoglobin added to the exofacial side of isolated membranes, respectively, reduced I'/I by 18% and 5%. In normal red cell membranes, pyrene mobility appears to be higher in the inner monolayer than in the outer one. In spherocytic membranes our results indicate an enhanced transmembrane asymmetry in lipid monolayer fluidity, probably due to a defect of the membrane protein skeleton organization.

Cholesterol↗
PubMed1988

Ca2+ influx in normal and spherocytic red cells.

The influx of 45Ca2+ into normal red cells and various types of spherocytic red cells was studied after blocking active Ca2+ extrusion by vanadate. The measurements were performed with and without verapamil, a calcium antagonist. The influx of Ca2+ into red cells from unsplenectomized persons was 22 +/- 7 mumol/l packed red cells/h (mean +/- SD), and 17 +/- 7 mumol/l per h when incubated with verapamil. The influx of Ca2+ into red cells from four splenectomized normal controls was of the same magnitude as in the unsplenectomized controls but there was no effect of verapamil on the influx rate. The influx of Ca2+ into red cells from nine splenectomized patients with hereditary spherocytosis (HS) was 27 +/- 9 mumol/l per h without and 24 +/- 9 mumol/l per h with verapamil. In 9 normal red cell samples made spherocytic by thermal damage the corresponding values were 32 +/- 16 and 31 +/- 19 mumol/l per h, respectively. The uptake of Ca2+ in chlorpromazine-induced spherocytic red cells was 20 +/- 4 mumol/l per h without and 19 +/- 5 mumol/l per h with verapamil in 9 experiments. These results indicate that although in HS erythrocytes changes in the cell membrane lead to an increased Ca2+ influx, the slow calcium channels are not affected, whereas in spherocytes induced by thermal damage or by incubation with chlorpromazine the channels are blocked, at least partly.

Adult↗
PubMed1979

Reconstitution of spectrin-deficient, spherocytic mouse erythrocyte membranes.

To study directly the role of spectrin in erythrocyte membrane function, we have designed a reconstituted membrane system using erythrocyte membranes from spectrin-deficient mice and purified spectrin from normal mice. The normal spectrin is inserted into the spectrin-deficient spherocytes by exchange hemolysis. Thereafter, raising the ionic strength and temperature reseals the cells and, with time, facilitates binding of the spectrin to the spectrin-deficient membranes. The binding is apparently specific as shown by its dependence upon the concentration of undenatured spectrin and the concentration of salt used, as well as by the immunofluorescent appearance of the reconstituted cells after treatment with specific antispectrin antibody. In terms of in vitro cellular behavior, the reconstituted preparations show marked changes in comparison to the untreated spherocytes. In particular, membrane stability, as measured by the reduction of myelin figure formation and lipid loss, is considerably enhanced. In addition, membrane fusion, which occurs readily with the untreated spherocytes, is virtually eliminated. Finally, the osmotic behavior of the native spherocytes is appreciably altered, such that the early phase of osmotically induced swelling, as measured in a high-speed stop-flow apparatus, is delayed and modified. Taken together, these findings indicate specific roles for spectrin in the stabilization of the erythrocyte membrane, in the limitation of membrane fusion, and in the modulation of the membrane's response to osmotic stress.

Animals↗
PubMed1976

Red cell velocity and plasma transit time in the cerebral microcirculation of spherocytic deer mice.

Spherocytic deer mice provide a model of human spherocytosis. Their erythrocytes are abnormal in shape and are more rigid than normal red blood cells (RBC). Like their human counterparts, spherocytic mice are anemic. Measurements of RBC velocity in microvessels on the cerebral surface failed to reveal a difference between the velocity of cells in spherocytic as compared to normal deer mice. However, plasma transit, as measured by fluorescein microangiography, was faster than normal. Both decreased plasma transit time and increased RBC velocity are expected in nonspherocytic, anemic mice. Since the former, but not the latter, was found in the spherocytic, anemic mice, it appears that increased RBC rigidity has a greater effect on RBC movement than on plasma movement within the cerebral microcirculation. Thus iit would seem that this increased RBC rigidity prevents the increased RBC velocity that otherwise would be observed in anemia but does not prevent the decrease in plasma transit time.

Animals↗
PubMed1992

Band 3 Tuscaloosa: Pro327----Arg327 substitution in the cytoplasmic domain of erythrocyte band 3 protein associated with spherocytic hemolytic anemia and partial deficiency of protein 4.2.

Protein 4.2 is a major red blood cell (RBC) protein that interacts with the band 3 protein and with ankyrin. Inherited deficiencies of this protein are associated with spherocytic hemolytic anemia, but the molecular basis of this defect is unknown. We have studied the underlying defect in a patient with spherocytic hemolytic anemia whose RBCs had a partial (29% +/- 5%) deficiency of protein 4.2. We have first studied the binding of normal ankyrin and protein 4.2 to patient inside-out vesicles (IOVs) stripped of peripheral proteins. While the binding of ankyrin was normal, the predicted maximal binding capacity of patient IOVs for band 4.2 was 20% to 33% lower than that of control IOVs, suggesting a defect in the cytoplasmic domain of band 3 (cdb3). An additional line of evidence pointing to a possible abnormality of band 3 was an abnormal proteolytic digest of cdb3. To elucidate the underlying molecular defect, we have cloned and sequenced the cDNA coding for cdb3 from the patient. One band 3 allele was found to be normal, while clones corresponding to the other allele contained two mutations: substitution A----G in nucleotide 166, changing codon 56 from AAG to GAG (Lys----Glu), and substitution C----G in nucleotide 980, changing codon 327 from CCC to CGC (Pro----Arg). Since the Lys56----Glu56 substitution is found in a common asymptomatic variant of the band 3 protein designated band 3 Memphis, we conclude that either the Pro327----Arg327 substitution itself, or in combination with the band 3 Memphis polymorphism, underlies the abnormal binding of protein 4.2 to cdb3 and results in the spherocytic phenotype.

Amino Acid Sequence↗
PubMed1978

31P-NMR study on nucleotides and intracellular pH of hereditary spherocytes.

As determined by 31p-NMR spectroscopy, intracellular pH of hereditary spherocytes was lower (pH 6.7-6.9) than that of normal red cells. The level of adenosine diphosphate in hereditary spherocytes was found to be persistently high. The metabolism of nucleotides and other phosphoryl compounds in human red blood cells have been studied in detail by 31p-MNR spectroscopy. However, to our knowledge, there seems to be no report describing the result of 31p-NMR spectroscopy on red blood cells from hereditary spherocytosis.

Adenosine Diphosphate↗
PubMed1984

Lateral mobility of phospholipids in the external and internal leaflets of normal and hereditary spherocytic human erythrocytes.

The lateral diffusion coefficients (D) and the mobile fractions of the fluorescent phospholipid N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)phosphatidylethanolamine (NBD-PE) and of membrane proteins labelled with fluorescein isothiocyanate, were measured by fluorescence photobleaching recovery on erythrocytes from healthy persons and from a hereditary spherocytosis patient. Measurements of lipid probe mobility were performed on ghosts labelled by NBD-PE exclusively at the external monolayer, or at both sides of the membrane. Our results indicate the following: (1) The mean values and the temperature dependence of D are different at the external and internal membrane leaflets. (2) In both normal and HS ghosts the mobile fraction of NBD-PE in the external monolayer does not depend significantly on temperature. On the other hand, the mobile fraction in the internal monolayer is reduced as the temperature is decreased. (3) At low temperatures, the mobile fraction of NBD-PE in the internal monolayer of spherocytic ghosts is significantly lower than the mobile fraction in the internal monolayer of normal ghosts. (4) No differences were observed between the mobilities of membrane proteins in normal and in spherocytic ghosts. However, differences were observed between the two cell populations in the temperature-dependence of the intrinsic fluorescence of unlabelled membrane proteins. The implications of these results for membrane phospholipid asymmetry and for cytoskeletal interactions with the internal lipid monolayer are discussed.

Erythrocyte Membrane↗
PubMed1980

Lateral mobility of integral membrane proteins is increased in spherocytic erythrocytes.

Alterations of glycoprotein distribution and lateral mobility in cell membranes can provide transmembrane signals for several membrane-related phenomena. Control of the transmembranous events has been ascribed to interaction between submembranous protein matrices (or 'cytoskeletons') and membrane glycoproteins. A consequence of such interaction would be differential inhibition of protein lateral diffusion in biological membranes. Measurements of the lateral diffusion coefficients of membrane proteins, in fact, have generally yielded values much less than were predicted for unhindered diffusion in a fluid bilayer. The mouse spherocytic erythrocyte, which lacks the major components of the normal erythrocyte membrane matrix (composed of spectrin, actin, bands 4.1 and 4.9 (ref. 16), in the nomenclature of Fairbanks et al.), provides a unique system for a direct evaluation of the effect of the matrix on protein lateral mobility. After using a modification of the technique of fluorescence redistribution after photobleaching (FRAP), we report here that membrane proteins diffuse about 50 times faster in spherocytic than in normal mouse erythrocytes.

Animals↗
PubMed1985

Transformation of erythrocytes to spherocytes following incubation with malignant cells.

Incubation of erythrocytes from controls and patients with colorectal carcinoma with tumor cells, or their metabolites, caused transformation of the normally-shaped cells to spherocytes. It is assumed that abnormal metabolites produced by malignant cells affect the cell membrane inducing the subsequent appearance of spherocytes. The increased destruction of these cells by the reticuloendothelial system may serve as an additional factor for the explanation of anemia accompanying malignant diseases.

Colonic Neoplasms↗
PubMed1975

Diphenylhydantoin and fragility of erythrocytes in normal subjects and in patients with hereditary spherocytic anemia.

To study the effects of diphenylhydantoin (Dilantin, DPH) on membrane function, DPH was incubated with erythrocytes from normal individuals and from patients with congenital spherocytic hemolytic anemia and osmotic fragility measured. The resulting curves show that DPH reduces the osmotic fragility of normal and spherocytic erythrocytes. In the presence of ouabain, DPH still had a protective effect on erythrocytes even though ouabain alone increases hemolysis of erythrocytes at certain saline concentrations. This study shows that erythrocyte fragility can be manipulated in vitro and provides a basis for studies in vivo.

Adolescent↗
PubMed1990

Fate of human albumin microsphere and spherocyte radioaerosols in the human tracheobronchial tree.

Human albumin microspheres (99mTc-HAM; 7-25 microns) and spherocytes (99mTc-S; 4-4.5 mu) are particles used for lung mucociliary clearance (MCC) measurements. If radiolabelled HAM aerosols are sent through an airway model to a screen, they appear peripherally distributed, whereas S present a more central and homogeneous distribution. The radioscanning evaluation of particle sedimentation in saline-filled tubes shows quite a different behavior pattern for S, HAM, and surfactant-coated HAM (S-C HAM). In these experimental conditions, S-C HAM and HAM floating properties were better than those of S. This could be explained by physical-chemical factors. Looking for the fate of organic particles after inhalation, we performed multiple bronchial biopsies in seven bronchitic patients, 2 h following inhalation of HAM and S. Scanning electron microscopy revealed that most of S was floating on the mucus layer, while HAM appeared deeply imbedded inside the mucus and partially digested. The same study performed on three bronchitic patients after S-C HAM inhalation, shows that S-C HAM float like S. In vitro, the time-course of tryptic digestion is similar for HAM and for S. However, in vivo, the different location of each particle on the bronchial surface might lead to a different digestion by trypsin and by PZ-peptidase, which are dosable in pathologic mucus. In our opinion, if HAM are coated with surfactant, this should improve the mucus-HAM interaction, thus helping to control variability in lung radioaerosol MCC studies.

Aerosols↗
PubMed1988

Coombs'-negative spherocytic hemolytic anemia and severe necrotizing renal vasculitis.

Vasculitis may be complicated by either hypoproliferative or hemolytic anemias. We have described a patient with a Coombs'-negative spherocytic hemolytic anemia and severe necrotizing renal vasculitis, two disorders not having been previously linked. The disorders were temporally related and both responded to immunosuppressive therapy. The precise cause of the hemolytic anemia remains unknown.

Aged↗
PubMed1986

Neonatal anti-Kell isoimmune hemolytic disease with spherocytes.

Two infants with hemolytic disease of the newborn due to Kell incompatibility are described. The peripheral blood smears revealed many spherocytes. This important hematologic sign in a neonate suggests not only ABO incompatibility, hereditary spherocytosis, or G6PD deficiency, but also the possibility of Kell incompatibility.

Blood Group Incompatibility↗
PubMed1995

Lethal congenital non-spherocytic, non-immune hemolytic anemia with genital and other anomalies in two brothers.

Non-consanguineous healthy parents had 2 boys with severe, non-spherocytic, nonimmune hemolytic anemia, abnormalities of their external genitalia, flat occiput, dimpled earlobes, deep plantar creases, and increased space between their first and second toes. The birth of these children was separated by a spontaneous abortion at 3 months and delivery of a normal girl. We propose that these boys have a heretofore undescribed autosomal or X-linked recessive syndrome.

Abnormalities, Multiple↗
PubMed1979

Congenital non-spherocytic haemolytic anaemia variants with primary and secondary pyruvate kinase deficiency. I. Erythrokinetic patterns.

The patterns of survival of isotope-labelled erythrocytes were examined in patients suffering from two variants of congenital non-spherocytic haemolytic anaemia with decreased erythrocyte pyruvate kinase (PK) activity. In one variant, with primary PK defect (PPKD) random destruction of erythrocytes was predominant in the process of haemolysis. In the second variant, with primary magnesium activated adenosine triphosphatase (ATP-ase) (Mg++) deficiency and a secondary decrease in PK activity, erythrocytes were destroyed by senescence. Two subpopulations of labelled erythrocytes with different destruction rates were observed in all patients examined, except one with the second variant, with very mild haemolysis. Splenectomy, performed on two patient, was successful only in the variant with PPKD.

Adenosine Triphosphatases↗
PubMed1979

Congenital non-spherocytic haemolytic anaemia variants with primary and secondary pyruvate kinase deficiency. II. Enzymatic studies.

Some metabolic effects associated with defective pyruvate kinase (PK) in two variants of congenital non-spherocytic haemolytic anaemia with primary PK and primary adenosine triphosphatase (ATP-ase) (Mg++) deficiency respectively we compared. In one patient with a low erythrocyte ATP level, decreased PK activity appeared together with the irreversible loss of its sensitivity to fructose-I,6-diphosphate (FDP), independently of the experimental conditions. In the second patient, the decrease in PK activity associated with an elevated erythrocyte ATP level was a secondary effect, due to primary ATP-ase (Mg++) deficiency. Removal of excessive amounts of ATP, by dialysis of haemolysates or their in-vitro treatment with ATP-ase, increased PK activity to the normal range and restored its sensitivity to the stimulatory effect of FDP. Similar effects could be obtained after i.v. administration of magnesium laevulinate. Under these in vivo conditions the ATP level was normalized after a transient rise ATP-ase activity, the PK activity increased and its sensitivity to FDP reappeared.

Adenosine Triphosphatases↗
PubMed1987

An improved acidified glycerol lysis test (AGLT) used to detect spherocytes in pregnancy.

The acidified glycerol lysis test (Zanella et al, 1980) had proved unreliable in our hands. We now report the test to be stable and reliable when conducted at 37 degrees C rather than at ambient laboratory temperature as used by earlier workers. With this modification, blood samples were tested from 167 pregnant subjects. Forty-eight were less than 26 weeks pregnant and gave normal AGLT values (T50 greater than 1800 s) while of 119 more than 26 weeks pregnant 57 (48%) gave shortened T50 values indicative of the presence of spherocytes.

Female↗
PubMed1992

Molecular basis of chronic non-spherocytic haemolytic anaemia: a new G6PD variant (393 Arg----His) with abnormal KmG6P and marked in vivo instability.

More than 80 genetic variants of glucose-6-phosphate dehydrogenase (G6PD) are associated with chronic non-spherocytic haemolytic anaemia (CNSHA). In order to help clarify the molecular basis of this association, we have carried out a detailed biochemical and genetic characterization of two G6PD deficient brothers affected by CNSHA. The G6PD from the two patients has altered electrophoretic mobility, abnormally elevated Michaelis constant (Km) for G6P, and extreme instability in vivo and in vitro. By comparison with published information we found that this is a new G6PD variant which we have designated G6PD Portici. The entire coding region of the gene has been sequenced, and a single point mutation, a G----A transition, was found at position 1178 in exon X, causing a substitution of histidine for arginine at residue 393 in the polypeptide chain. By polymerase chain reaction (PCR) amplification followed by diagnostic restriction enzyme analysis and allele-specific oligonucleotide hybridization we have demonstrated the inheritance of this mutation in the patient's family. Our results support the notion of a causative link between this mutation in the G6PD gene and CNSHA. Our data, in combination with previous data in the literature, suggest that the three-dimensional structure of G6PD is such as to cause interaction in the binding of its two substrates, G6P and NADP.

Adolescent↗