Search Results
Results 901 - 950 of 983
< 10 11 12 13 14 15 16 17 18 19 20 >
Clark M R - - 1978
Discontinuous Stractan gradients were used to separate heterogeneous populations of sickle cells into discrete subpopulations containing varying proportions of reticulocytes, mature discoid cells, and irreversibly sickled cells (ISC). The improved homogeneity of these preparations, together with an enhanced yield of ISC, allowed us to distinguish effects of cell maturation from ...
Ray B - - 1978
The sensitivity of Vibrio parahaemolyticus cells to refrigeration and frozen storage and the development of a method for detecting injured and uninjured V. parahaemolyticus cells were studied. Cell suspensions in different kinds of seafood homogenates were either regrigerated (4 degrees C) or frozen (-20 degrees C), stored, and examined for ...
Leblond P F - - 1978
The deformability of three previously described morphological populations of erythrocytes from splenectomized pyruvate kinase (PK) deficient patients was assessed using both Nucleopore filtration and micropipette techniques. Mean deformability was decreased in fresh cells from all patients studied. Selective measurements indicated that immature lobulated reticulocytes in each patient were the least ...
Sanderson C J - - 1978
Antibody dependent cytotoxicity of chicken erythrocytes by purified rat eosinophils, neutrophils, macrophages and K cells has been compared by 51Cr release and time lapse microcinematography. Techniques have been developed for purifying these effector cell types. Both eosinophils and neutrophils cause rapid release of 51Cr from erythrocytes. Time lapse observations indicated ...
Nei T - - 1978
Freezing patterns and post-thaw survival of cells varies with different cooling rates. The optimal cooling rates, indicating the highest percentage survival, were different in yeast and red blood cells. A difference of freezing patterns was also noticed in preparations frozen above and below the optimal cooling rate for each cell, ...
Cameron B F - - 1978
There is an exchangeable calcium pool in both normal and sickle cell erythrocytes, comprising about 10-15% of the total cellular calcium. Sickle cells show increased calcium as compared to normal cells in the oxygenated state. Specific differences between sickle and normal cells which may be associated with this fact are ...
Burton B K - - 1978
Two acidic forms of alpha-mannosidase activity, A and B, are separated and characterized in fibroblasts from controls and patients with mannosidosis. In normal cells, A and B differ in adsorption on DEAE-cellulose, electrophoretic mobility, stability at 70 degrees C and resistance to freezing at --20 degrees C. In 5 of ...
Hill R S - - 1978
Human peripheral blood leucocytes (neutrophil-rich) were collected either with heparin or acid citrate dextrose, frozen with dimethyl sulphoxide at a controlled rate, stored in liquid nitrogen at--196 degrees C and reconstituted with a solution containing dextran. After reconstitution, 20.2% of cells (in absolute numbers 1 in 5 fresh cells) showed ...
Wagner E S - - 1977
Benzylpenicillin, 5.2% 14C-enriched, was incubated with human whole blood. The erythrocyte component was washed and exhaustively dialyzed and found to contain 6.3% of the original radioactivity. None of the penicillin was found to bind to the cell membrane. Dialysis of the cell contents indicated that none of the penicillin binds ...
Slor H - - 1977
A variety of cell strains and lines were frozen and thawed by conventional techniques for cell storage. Following thawing, extracts of cells were prepared and incubated with UV-irradiated E. coli DNA. Thymine dimer excision activity present in extracts of unfrozen cells was lost in extracts of recently thawed cells. The ...
Tsai C M - - 1977
A purified human monoclonal IgM(kappa) (cold agglutinin MKV) has been characterized as both a cold agglutinin and a cryoglobulin. Since its reactivity with human erythrocytes but not with dog erythrocytes is reduced by treatment of the cells with ficin and its reactivity with both is abolished by treatment of the ...
Palta J P - - 1977
Onion (Allium cepa L.) bulbs were frozen to -4 and -11 C and kept frozen for up to 12 days. After slow thawing, a 2.5-cm square from a bulb scale was transferred to 25 ml deionized H(2)O. After shaking for standard times, measurements were made on the effusate and on ...
Farrant J - - 1977
The cooling procedures used to prepare samples for ultrastructural examination at low temperatures often differ markedly from those used to recover optimal function of cells on thawing. The implications of these differences are reviewed. Damage and alteration to the structure and function of the cells may be caused by the ...
Echlin P - - 1977
A study has been made of the physiological effects of three non-penetrating polymeric cryoprotective agents on sixteen different plant and animal cells and tissues. The cryoprotectants, when used at concentrations at which they are effective in preventing ice-crystal formation, generally have a lower toxicity to cells and tissue than similar ...
Farrant J - - 1977
This paper discusses two important biological factors contributing to the death of cells within any region that is frozen cryosurgically. The first factor is the relationship between cell death and the thermal history experienced by each cell. Freezing with a single probe as usually done cannot provide sufficiently uniform conditions ...
Andersson J - - 1977
The B-cell mitogens LPS and lipoprotein stimulate 20-35 percent of all B cells in the spleen of 6- to 8-wk old C3H/Tif mice, as determined by limiting dilution analysis of precursors. Each reactive cell grows to a clone of IgM-secreting PFC, enumerated in a hemolytic plaque assay detecting all IgM ...
Marquez B J - - 1977
To test the cryoprotective action of glycerol, intravaginal (I.V.A.I.) and intramagnal (I.M.A.I.) artificial inseminations were performed on 100 turkey hens using semen treated with glycerol; treated with glycerol then diluted and centrifuged; treated with glycerol and frozen-thawed; treated with glycerol, frozen-thawed then diluted and centrifuged; and untreated control. With I.V.A.I. ...
Borsos T - - 1977
The interaction of d.l. activity with chicken red cells (CE) generates a cell intermediate with the properties of classical E*. Generation of CE* by d.l. activity at 37 degrees C is rapid, while there is a considerable lag in the conversion of CE* to ghost and hemoglobin. Conversion of CE* ...
Lee S K - - 1977
Eight species of bacteria representing rod, coccus, gram-positive, and gram-negative forms were tested for their sensitivity to sodium chloride during freezing and thawing. Six of the eight species tested were salt-sensitive, though to different degrees, while Lactobacillus casei and Streptococcus faecalis were resistant. Escherichia coli grown anaerobically exhibited only 38% ...
Farrant J - - 1977
Living cells may be cooled to 77 K (liquid nitrogen) either to destroy them selectively or to store them for long periods. Water transport across the cell membranes during freezing and thawing is a primary factor determining whether the cells survive. These water movements are controlled by phase changes both ...
Price T H - - 1977
A rabbit model was developed to study the in vivo viability of neutrophils stored in vitro for up to 72 h. Acid-citrate-dextrose anticoagulated whole blood was obtained from rabbits previously injected with tritiated thymidine ([3H]thymidine), stored under varying conditions, and then injected into recipient rabbits. Neutrophil viability and function were ...
Dean D A - - 1977
Frozen stored human mononuclear cells were compared with non-frozen cells as responder cells in the monocyte chemotaxis assay. Frozen stored cells were found to inhibit lower background migration, resulting in greater experimental-to-control ratios. The use of frozen cells also greatly improved the speed, standardization of conditions and day-to-day reproducibility of ...
Leene W - - 1976
Density separation of rabbit thymus lymphoid cells on a continuous and linear Ficoll-Metrizoate gradient resulted in the appearance of three subpopulations of lymphoid cells with peak fractions at densities of approx. 1.067, 1.077 and 1.084 g/ml. The subpopulation of the lowest density appeared to consist of cortisone-resistant cells of various ...
Lin P S - - 1976
A mouse renal adenocarcinoma (Rag) cell line, not related to L cells, rosette with erythrocytes from sheep and mice. The Rag-cell rosettes are performed in suspension and on coverslips. Microscopically they rosette like human T cell. No virus-like particles thus far have been found between the rosetted cells. However, the ...
Higgins M L - - 1976
After the addition of glutaraldehyde (GA) to cells incubated at 3 or 37 degrees C, mesosomes were observed with increasing frequencies in freeze fractures of cells. These increases were related to the kinetics with which GA cross-linked adjacent amino acids. Upon the addition of GA, mesosomes were first observed in ...
Hassan W - - 1976
Incubation of sickle cells with cystamine, a thiol reagnet, resulted in the formation of an intracellular S-ethylamine derivative. The rate of the reaction was dependent upon the cystamine concentration, the temperature, and the duration of the incubation. The cystamine-treated cells demonstrated a marked inhibition of sickling under hypoxic conditions, a ...
Kleijer W J - - 1976
Prenatal diagnoses were established in 3 pregnancies at risk for GM1-gangliosidosis at 9, 10, and 12 days after amniocentesis. Beta-galactosidase activities in cultured amniotic fluid cells were determined by microchemical assays in cell homogenates and in isolated groups of 10--30 freeze-dried cells. The latter method requires only a few hundred ...
Birkeland S A - - 1976
The influence of a series of factors on the frozen storage of lymphocytes was investigated. The cells were frozen using different freezing programmes, using the cryoprotectants dimethyl sulphoxide and glycerol in different concentrations in the freezing medium, and with variations in the period of exposure of cells to cryoprotectants before ...
Frim J - - 1976
Unprotected, mammalian cells in plateau phase are at least a factor of four times more sensitive to freeze-thaw damage than exponential-phase cells. The former suffer about 15-20% more sublethal damage after one freeze-thaw cycle than the latter and repair this damage more slowly. Exposure of plateau-phase cells to freeze-thaw damage ...
Gergely P - - 1976
Compared to peripheral blood lymphocytes the ability of human tonsil T cells and MLC blasts to bind sheep, human and horse erythrocytes was found to be increased. Tonsil and MLC T cells were able to bind sheep red blood cells without any cold incubation, i.e. they were 'early' rosettes, and ...
Shporer M - - 1976
Lymphocytes obtained from thymus glands of normal rats and culture lines of malignant rat thymocytes were enriched with H217O. The longitudinal and transverse relaxations of the 17O were determined separately in samples of packed cells and supernatant solutions. The longitudinal relaxation of intracellular 17O of fresh viable lymphocytes was nonexponential, ...
Chandler J A - - 1976
X-ray microanalysis of air dried and ultrathin frozen and frozen dried sections of human sperm cells has indicated a large deviation of elemental composition between cells in a single sample and between samples. Analysis of air dried cells indicates a similar subcellular elemental distribution to that found in sectioned material. ...
Dahlager J I - - 1976
Collins' solution is an excellent medium for kidney preservation by simple cold storage before transplantation. Efforts by Sacks et al. to improve this technique by modifying the composition seemed promising. A comparison between ability of these two media to preserve the tubular cell was attempted. The viability of the tubular ...
Murphy J R - - 1976
Studies of the rheological properties of Hb SS blood indicate that the marked increase in viscosity with deoxygenation is primarily due to cell-cell interaction of cells which were not permanently deformed. The permanently deformed cells, the bottom fraction of cells separated by centrifugation, show only a fraction of the increase ...
Towill L E - - 1976
Haplopappus gracilis and Acer saccharum tissue culture cells are extremely sensitive to freezing injury, and exhibit a decrease in survival from 98% at -1 C to 4% at -3 C (Haplopappus) and 92% at -3 C to 13% at -5 C (Acer) when suspended in distilled H(2)O, seeded at -1 ...
Böhm F - - 1976
Mouse plaque-forming cells were kept at--196 degrees C for different periods of time up to 37 weeks. The decrease in cell number occurring during the storage was found to be in no correlation with the length of the storage time. The cryoprotective effectiveness of dimethyl sulphoxide upon survival of cells ...
Brewer G J - - 1976
In summary, red cell carbohydrate metabolism plays an important role in the cell, both for maintaining cell viability through ATP and for maintaining proper oxygen release through DPG. These functions are compromised by traditional liquid storage. Frozen storage maintains these functions for an indefinite period of time. However, the cells ...
Weiner R S - - 1976
Human lymphocytes can be cryopreserved for the purpose of performing in vitro tests of cellular immunity. A systematic study of the conditions for freezing and recovering cells has shown that there is wide flexibility in cell concentrations of cryoprotective agent and the temperature and rate of dilution however, have definable ...
Wood W G - - 1975
Specific antibodies to human fetal hemoglobin were prepared and, after conjugation with a fluorescent dye, were used to determine the distribution of Hb F-containing cells in blood smears from normal adults and individuals with hereditary and acquired conditions associated with abnormal levels of Hb F. The mean proportion of F-cells ...
Valet G - - 1975
Sheep erythrocytes were sized by an electrical method during lysis by antibody and complement. No volume changes were observed upon to the EAC1-8 cell intermediate. Three steps could be distinguished in the reaction of C9 with EAC1-8 cells: fixation of C9 to EAC1-8 cells, a process which proceeds also at ...
Boyer S H - - 1975
Fetal hemoglobin (HbF) in adult life is usually restricted to a few erythrocytes called F-cells. Their presence can be detected and the quantity of HbF per F-cell estimated by pericellular immunodiffusion reactions with anti-HbF. In normal adults F-cell frequency (range: 1 F-cell per 25 erythrocytes to 1 per 6800) and ...
Netzel B - - 1975
A method of freezing LD typing cells in microtiter plates was developed. Two times 10(5) lymphocytes in a small volume (15 mul) with a low DMSO concentration (5%) were directly frozen in a --70 degrees C freezer. These cells were used in the mixed lymphocyte culture after thawing by diluting ...
Osborne J A - - 1975
The toxicity of several cryoprotective agents was tested at room temperature (23 C) against Tetrahymena pyriformis strain S (Phenoset A) at different stages of growth cycle. Polyvinylpyrrolidone (PVP-40) at 10 per cent (v/v) concentration was without effect at any stage in the growth cycle, while 1.2 M glycerol immobilized the ...
Osoba D - - 1975
Human peripheral blood leukocytes retain their capacity to function as stimulating cells in the one way MLR after freezing and storage at - 70 degrees C by a simple and inexpensive method. This storage method facilitates the use of a standard stimulating pool of cells from three donors which may ...
Sutera S P - - 1975
By means of glutaraldehyde fixation, human erythrocytes are "frozen" while suspended in turbulent shear flow. As the shearing is increased in steps from 100 to 2,500 dyn/cm2, the deformed cells evolve gradually toward a smooth ellipsoidal shape. At stresses above 2,500 dyn/cm2, approximately, fragmentation of the cells occurs with a ...
Ganguly R - - 1975
Storage of intact macrophages would be a useful procedure for laboratories studying the biological functions of these cells. Oil-induced guinea pig peritoneal cells were harvested and frozen at an ultra-low temperature using a cryoprotective media. Studies of the biological properties of the frozen cells upon thawing indicated that the cells ...
Ryan M M - - 1974
We have devised a system for controlled cooling of living cells which eliminates the need for complicated, expensive equipment but allows excellent recovery of viable cells after storage in liquid nitrogen.
Geiger D R - - 1973
The distribution of solutes in the various cells of sugar beet (Beta vulgaris L.) source leaves, petioles, and sink leaves was studied in tissue prepared by freeze-substitution. The differences in degree of cryoprotection indicated that sieve elements and companion cells of the source leaf, petiole, and sink leaf contain a ...
Janssen D W - - 1973
Fast freezing and slow thawing Salmonella anatum cells in various milk components inactivated from 20 to 98% of the cells and damaged 40 to 90% of the cells surviving the treatments. Injured cells failed to form colonies on a selective medium (xylose-lysine-peptone agar with 0.2% sodium deoxycholate) but did form ...
Cloran J - - 1973
Lyophilized cells of Bacillus popilliae were protected from moisture when suspended in pellets of tung oil polymer which were then coated with paraffin wax. The survival of the protected cells at various levels of relative humidity (RH) and under various storage conditions was determined. During 6 months of storage, moisture ...
< 10 11 12 13 14 15 16 17 18 19 20 >