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Results 701 - 750 of 983
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Beck F X - - 1988
We studied the effect of acute metabolic acidosis on potassium, sodium and chloride gradients across the apical membrane of proximal and distal tubule cells by determining electrolyte concentrations in individual cells and in tubule fluid employing electron microprobe analysis. Cellular measurements were performed on freeze-dried cryosections of the renal cortex, ...
Coletta M - - 1988
Red blood cells from patients homozygotes for hemoglobin S (HbS) have been studied using a computer-controlled microspectrophotometer, which allows measurements of spectra and dynamics to be undertaken in a single erythrocyte. Complete photodissociation of HbCO results in polymerization of intracellular deoxyhemoglobin S and deformation of the cell. This is associated ...
Sung K L - - 1988
Study of the mechanical properties of leukocytes is useful to understand their passage through narrow capillaries and interaction with other cells. Leukocytes are known to be viscoelastic and their properties have been established by micropipette aspiration techniques. Here, the recovery of leukocytes to their normal spherical form is studied after ...
Nash G B - - 1988
The transformation of less-dense, discoidal homozygous sickle cells (HbSS) RBCs into dehydrated, rheologically impaired cells is believed to be an important factor in the pathophysiology of sickle cell disease. We investigated this process by subjecting the less-dense fraction of HbSS RBCs, which contains a low percentage of irreversibly sickled cells ...
Falcieri E - - 1988
A simple, high-yield technique for the freeze-fracturing of small amounts of isolated cells is described. A drop of cells fixed in suspension is deposited on a polylysine-treated coverslip, forming a monolayer through electrostatic forces. After cryoprotection, the coverslip is inverted on a gold carrier covered with Vinol and then frozen ...
Chau M F - - 1988
Twelve laser-irradiated cell lines and eight cis. platin-treated cultures possessing defective micronuclei exhibited micronuclear and oral abnormalities during autogamy. Micronuclear abnormalities were characterized by the failure of some of the cells to complete the micronuclear cycle resulting in the absence of either micronuclei or macronuclear anlagen, or both. Oral abnormalities ...
Tvedt K E - - 1988
A quick sampling and preparation method for freezing of cell monolayers is described. The cells are grown on a large Formvar film supported by a frame of polystyrene. A polyvinylpyrrolidone (PVP) solution is applied to one side of the film forming a flat disc when frozen with a pair of ...
Bock J L - - 1988
Free intracellular Mg2+ concentration ([Mg2+]i) was measured in cold-stored human erythrocytes by the method of null-point titration with ionophore A23187. [Mg2+]i was 311 +/- 41 microM (mean +/- S.D.) for cells stored 0-10 days, increasing to 458 +/- 64 microM for cells stored 22-48 days. The values for stored cells ...
Kruuv J - - 1988
L-Glutamine at 18 mM protects mammalian cells against freeze-thaw (FT) damage by a factor of about 6, depending on FT conditions, in balanced salt solutions. While not nearly as effective a cryoprotectant as dimethyl sulfoxide (DMSO) or propylene glycol (PG), the mechanism of protection by glutamine appears to be independent ...
Carroll J - - 1988
To assess possible functional effects of the procedures involved in freezing/thawing of mammalian embryos, uptake of 3H-glycine and 125I-BSA (bovine serum albumin) was measured in mouse two-cell embryos and morulae before and after freezing. None of the procedures of dehydration, rehydration, or freezing affected glycine uptake significantly. Earlier results for ...
Shier W T - - 1988
Normally a freeze-thaw cycle is a very efficient method of killing mammalian cells. However, this report describes conditions that prevent killing of cultured mammalian cells by nucleated freezing at -24 degrees C. Optimal protection from cell killing at -24 degrees C was obtained in isotonic solutions containing an organic cryoprotectant ...
Mickols W E - - 1988
We have used differential polarization microscopy, which provides images of linear dichroism, to measure the percentage of aligned hemoglobin (Hb) in 1086 deoxygenated red blood cells from subjects with sickle cell anemia. The percentage was found to be only slightly dependent on the speed of deoxygenation, thus showing that the ...
Ng S F - - 1988
Removal of the micronuclei from Paramecium generated amicronucleate cell lines which produced oral apparatuses of much reduced length and abnormal oral membranellar pattern during an initial depression period. They subsequently recovered, but only partially. Reimplantation of the amicronucleates with micronuclei generally allowed a greater oral length to be reached in ...
Takano E - - 1988
The occurrence and molecular sizes of calpains and calpastatin in the lysates of human erythrocytes, platelets, lymphocytes/monocytes, and polymorphonuclear cells were studied by immunoelectrophoretic blot analysis. The basic uniformity among these cells of the 85-kDa and 83-kDa heavy subunits of low- and high-Ca2+-requiring calpains I and II, respectively, and of ...
Archer L M - - 1988
Vero cells, SP2/O-Ag 14 myeloma cells and 4B87 hybridoma cells were stored either at refrigeration (5 degrees C) or freezing (-18 degrees C) temperatures. Cells were recovered every five days and percentages of viable cells were determined by the trypan blue exclusion staining method before the cells were incubated at ...
Houle J J - - 1988
The hemolytic efficiency and binding of C9 to homologous and heterologous erythrocytes was evaluated by using a standardized passive sensitization procedure to prepare antigen- and antibody-coated erythrocytes (EA) and human serum for lysis. Heterologous bovine EA were readily lysed by human serum, whereas human EA were quite resistant to lysis. ...
Bissonnette N - - 1988
Whey, a by-product of the dairy industry, has been found to protect the rhizobia cells during freezing and thawing. Cells of rhizobia grown on whey sustained freezing better at -18 degrees C than did cells grown on mannitol or sucrose. Suspensions of cells grown on whey or mannitol that were ...
Croizat H - - 1988
We have examined the possibility that permanent "stress" hemopoiesis in sickle cell anemia (SS) patients leads to the modification of the behavior of circulating 14 day erythroid progenitor cells (BFU-E). In these patients we find that peripheral blood BFU-E are increased in number and have high sensitivity to erythropoietin (Epo). ...
Pajot N - - 1988
The sickle cell disease is characterized by a heterogeneous clinical and biological expression. In order to evaluate the prognostic significance of the red blood cell density distribution: D50 (median cell density of the distribution), R60 (middle density range in which 60% of the cells can be found), F4 and F5 ...
DeLoach J R - - 1987
Hypotonic dialysis of bovine erythrocytes to 160-180 mosmol/kg produces cells with metastable pores. Cells stored for 3 weeks in a hypotonic dialyzed state can be used to prepare carrier erythrocytes. Pores generated by nonlytic hypotonic conditions are initially greater than 40 A in radius but shrink to less than 20 ...
Horiuchi K - - 1987
Changes in density, morphology, and monovalent cation content of sickle (SS) cells caused by repetitive sickling were investigated in vitro with a device by which red cells can be exposed to cycles of deoxygenation and oxygenation (d-o cycles). Experiments were done using the discocyte-rich, less dense fractions of SS cells. ...
Meletis J - - 1987
The hemoglobin content was determined by microspectrophotometry in single erythrocytes with and without fetal hemoglobin (Hb F) from 16 normal subjects, 30 patients with anemia of different etiology and severity and 20 individuals with thalassemic disorders. Hb F-containing cells were identified by an indirect immunofluorescent method. The relative single cell ...
Stuart J - - 1987
Erythrocytes from 14 patients with homozygous sickle cell anaemia were treated with the calcium ionophore A23187 to induce loss of cellular potassium and water. The dehydrated cells showed a decrease in filterability (loss of deformability) through pores of 5 micron diameter. Oxpentifylline and cetiedil citrate, which preserve erythrocyte cation and ...
Van Voorhis H - - 1987
Using rats previously anesthetized with pentobarbital and with subtle modifications to existing procedures, rat brown adipocytes of good yield, viability, and stability were consistently obtained. The metabolic integrity of the cells, indicated by an 8-11 fold norepinephrine-dependent stimulation of respiration, was reproducible between cell preparations and maintained even after 3-5 ...
Shiloh H - - 1987
The purpose of this study was to investigate the effects of the freeze-thaw procedure on the ultrastructural features of human thyroid cells. Four different stages of thyroid cell preparation were compared: (1) fresh surgical tissue, serving as control, (2) cell suspension before freezing, (3) cell suspension after thawing, and (4) ...
Li Z S - - 1987
Pod walls of broadbean (Vicia faba L. cv Aguadulce) were harvested at the import (S(1)), at the transition (S(2)) or at the export (S(3)) phase for assimilate transport. Measurements of the transmembrane potential difference (PD) of mesocarp cells were made under various osmotic conditions. Internal osmotic potentials and cell turgor ...
Borrelli M J - - 1987
A modification of the protocol developed by Kawamoto, J C & Barrett, J N, Brain res (1986), in press for freezing primary neuron cultures in a solution containing low sodium and high lactate and potassium concentrations was used to freeze synchronous mitotic and G1 CHO cells. After thawing, the cells ...
Vassimon C S - - 1987
Rat peritoneal fluid mast cell present parallel increases in cell area (swelling), and in hydrolytic activity on the trypsin substrate p-tosyl arginine methyl ester (TAME), when placed in Tris buffers of concentrations between 0.15 and 0.03 M. Under these conditions, cells do not degranulate and preserve their trypsin-like enzyme activity ...
Kurantsin-Mills J - - 1987
Intracellular hemoglobin S (Hb SS) concentration, a function of cell hydration, has a major influence on the rate of Hb SS polymerization and, therefore, cellular sickling. To determine the density distribution of homozygous sickle hemoglobin cells as a function of cell hydration, cells were incubated in autologous plasma buffer mixtures ...
Dover G J - - 1987
We have developed methodology that allows comparison of the mean corpuscular hemoglobin (MCH) of fetal hemoglobin (HbF)-containing red cells (F cells) with the MCH of non-F cells from the same individual. To do this, suspensions of peripheral blood erythrocytes and their internal contents are fixed with an imidodiester, dimethyl-3,3'-dithiobispropionimidate dihydrochloride ...
Kon K - - 1987
The effect of shear force (depending on shear rate and viscosity of extracellular medium) and hematocrit of RBC suspension on RBC deformation was studied quantitatively using a cone-plate rheoscope with various kinds of cells, ie, partially hemolyzed (PH) cells, density-fractionated intact cells, and diamide-treated cells. The deformation index (DI) of ...
Schneider U - - 1987
This laboratory has previously reported that the survival of frozen-thawed human erythrocytes is determined more by the fraction of the extracellular solution that remains unfrozen than by the salt concentration in that fraction, especially when the cells are frozen at low hematocrit. To determine the extent to which these findings ...
Chien S - - 1987
The alterations in the viscoelastic properties of the hemoglobin S solution following deoxygenation can be correlated, on the one hand, with the gelation of the HbS molecules and, on the other hand, with changes in the rheological behavior of the deoxygenated SS erythrocytes. The abnormal rheology of SS erythrocytes forms ...
Armitage W J - - 1987
A wide range of cells of biological, medical and agricultural importance can be cryopreserved at -196 degrees C for many years in a stable state. The survival after freezing and thawing of different types of cell varies markedly, and depends on the ability of the cells to withstand a variety ...
Comoë L - - 1987
In view of new antitumor compounds which could exert their therapeutic effect through a combination of cell growth inhibition and cell maturation, we describe here the effects of a novel antileukemic alkaloid, fagaronine, on the growth and the induction of hemoglobin synthesis in the K 562 cell line. We found ...
el-Hazmi M A - - 1987
During an extensive investigation to determine the frequency of sickle cell and thalassaemia genes in the Saudi population, 22 cases with S/beta 0-thalassaemia were identified and the haematological, biochemical and clinical findings were compared with those in patients with sickle cell anaemia. The values of mean cell volume, mean cell ...
Gazaryan K G - - 1987
In the population of chick primary erythroblasts the quota of the G2-phase (tetraploid) cells is greatly increased probably due to the fact that a part of erythroblasts is reversibly blocked at this phase. An increased number of G2 cells is also detected in the population of reticulocytes at later stages ...
Kurantsin-Mills J - - 1987
The impaired deformability and heterogeneity of erythrocytes in sickle cell disease endows them with abnormal microvascular flow dynamics. In the sickle cell exchange-transfused rat model, sickle cells exhibit lower volumetric flux and shear rates compared to normal (HbAA) or autologous rat cells. A subpopulation of dense sickle cells and irreversibly ...
Charache S - - 1987
Five patients with sickle cell anemia were treated with hydroxyurea (HU), in hopes of augmenting their production of fetal hemoglobin. Laboratory responses in two patients treated for more than 2 years were encouraging and there were suggestions of clinical improvement. Long-term HU therapy should be considered for severely affected adults ...
Riley R T - - 1987
In a previous study (1) we demonstrated that increased tetraphenylphosphonium (TPP) uptake by renal epithelial cells (LLC-PK1) exposed to the fungal metabolite cyclopiazonic acid (CPA) was not a result of hyperpolarization across the plasma membrane even though CPA-potentiated TPP uptake could be totally inhibited by the depolarizing agent carbonylcyanide-m-chlorophenylhydrazone (CCCP). ...
Long W J - - 1986
A computerized system for the management of hybridoma cell growth data using voice input is described. The system permits the storage, retrieval, and analysis of data for hybridoma cells secreting monoclonal antibodies. It consists of a local system residing on a professional computer interfaced to a mainframe processing system. The ...
Joiner C H - - 1986
The mechanism by which sickle cells and xerocytic red cells become depleted of cations in vivo has not been identified previously. Both types of cells exhibit elevated permeabilities to sodium and potassium, in the case of sickle cells, when deoxygenated. The ouabain-insensitive fluxes of sodium and potassium were equivalent, however, ...
Ashmun R A - - 1986
A microspectrophotometric technique was used to measure the kinetics of methemoglobin reduction in intact, unaltered human erythrocytes. Reduction was catalyzed by endogenous NADPH-methemoglobin reductase in the presence of Nile Blue. The technique was applied to the study of erythrocytes from a female donor with decreased glucose-6-phosphate dehydrogenase (G-6-PD) activity. The ...
DeLoach J R - - 1986
Hypotonic dialysis of human erythrocytes results in porous cell stability for several days. Hypotonic cells stored for 1 week are essentially normal with respect to the preparation of carrier erythrocytes. Afterward, cells begin to irreversibly hemolyze resulting in decreased cell recoveries and decreased encapsulation percentages of two probes, sucrose and ...
Kar B C - - 1986
A study of 131 patients with homozygous sickle cell (SS) disease in Orissa State, India, indicated that, compared with Jamaican patients, Indian patients have higher frequencies of alpha thalassaemia, higher fetal haemoglobin, total haemoglobin, and red cell counts, and lower mean cell volume, mean cell haemoglobin concentration, and reticulocyte counts. ...
Gharapetian H - - 1986
A new, semipermeable hydrogel membrane for encapsulating viable cells has been developed. The encapsulation was performed by consecutively introducing droplets of a suspension of hybridoma cells in a solution of a polyanionic acrylic copolymer into aqueous solutions of three polycationic polymers. As a result of interpolymeric ionic interactions and some ...
Chandra S - - 1986
A freeze-fracture methodology was standardized for tissue culture cells to study intracellular distribution of diffusible elements with ion microscopy. Chinese hamster ovary (CHO) and normal rat kidney (NRK) cells grown on a silicon substrate were sandwiched using another smooth surface (silicon, glass, mica) in the presence of spacers and fast ...
Pomeroy M K - - 1986
Adenylate energy charge (AEC) and adenine nucleotide levels of isolated winter wheat (Triticum aestivum L. cv Kharkov 22 MC) cells exposed to various low temperature stresses were determined. During ice encasement at -1 degrees C, nucleotide levels decreased gradually in approximate relation to a decline in cell viability. AEC values ...
Venkataraman M - - 1986
We have studied the number of viable and functionally active T and B lymphocytes obtainable after cryopreservation to determine the best and most practical way to recover the maximal number of viable and functionally active cells. Assays were done on purified populations of human T and B cells recovered after ...
Obafemi A - - 1986
Antibacterial treatments for frozen poultry, including holding at -5 degrees C and slow thawing at 4 degrees C to which exponential phase cells of Salmonella typhimurium were susceptible, were found to be relatively ineffective against stationary phase cells. Exposure of the latter, however, to a pre-freezing triple stress treatment of ...
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