bluuebunny/crossref_metadata_2025_split huggingface dataset:
Permeabilization of lymphocytes with polyethylene glycol 1000. Discrimination of permeabilized cells by flow cytometry
Authors: Szabó Gábor , Kiss Attila , Trón Lajos 
Published: August 2005

AbstractThe toxicity of polyethylene glycol 1000 (PEG) used similarly as in cell hybridization experiments, has been studied by flow cytometry, measuring the light scattering and fluorescence distributions of PEG‐treated human lymphocytes stained with propidium iodide, fluorescein diacetate and acridine orange (AO). The sensitivity of these tests to detect permeabilized, or potentially dead cells, was equal. In addition, PEG proved to interfere with AO staining most likely through the inhibition of its binding to nucleic acids. The decrease of AO fluorescence in cells killed by PEG was unexpected since intercalation of propidium iodide was the same as in alcohol fixed cells. Permeabilization of cells by PEG appears to be an all‐or‐none phenomenon, accompanied by entrance of PEG into the cells. The findings are described in the context of a review of the currently used flow cytometric techniques to discriminate viable and lethally affected cells; also, the problems of interpretation are discussed.
Changes in DNA content of human blood mononuclear cells with senescence
Authors: Staiano‐Coico Lisa , Darzynkiewicz Zbigniew , Melamed Myron R. , Weksler Marc 
Published: August 2005

AbstractThe mean DNA content per cell and heterogeneity of cell populations with respect to DNA content were measured in samples of peripheral blood mononuclear cells from donors of different ages. Nearly all of the cells in these populations are found in the G1Q phase of the cell cycle. While the mean DNA content was the same for all age groups, a significant increase in intercellular variability, reflected by an increase in coefficient of variation of the mean, was observed in the group of subjects between 67 and 83 years of age in comparison with the group of donors between 20 and 30 years of age. The difference was observed regardless of whether cells were stained with acridine orange or propidium iodide, and under conditions where the intercellular variability cannot be attributed to differences in chromatin structure or quantity of mitochondrial DNA. Increasing cell heterogeneity may reflect the age associated deterioration of the fidelity of DNA replication and/or repair and provide a quantitative marker of the accumulated defects in the DNA of a cell population. The observed changes may be responsible for the decline in immune function with age.
Cell‐Cycle position and nuclear protein content
Authors: Roti J. L. Roti , Higashikubo R. , Blair O. C. , Uygur N. 
Published: August 2005

AbstractTo determine the change in nuclear protein content as a function of cell cycle position, isolated heLa nuclei were stained for protein with fluorescein isothiocyanate (FITC) and for DNA with propidium iodide (PI) and analyzed by flow cytometry (FCM). The resulting FITC versus PI histogram consisted of four definable regions, a G1 region characterized by increasing FITC and relatively constant PI (2C DNA content), an S region characterized by increasing PI with relatively constant FITC, a G2 region characterized by increasing FITC and constant PI (4C DNA content), and a region of G1 FITC staining with near G2 PI staining. The relationship between cell cycle position and these regions of the histogram was confirmed by the two following studies: (1) The distribution of labeled nuclei throughout the histogram was observed after [14C]TdR pulse labeling. (2) Exit of cells from G1 was observed in the histogram after the addition of Colcemid to the HeLa cell cultures. Nuclear protein content did not appear to increase uniformly across the cell cycle (defined by DNA content). Rather, nuclear protein content showed the largest increase during G1. Thus, dual parameter FCM analysis based on nuclear DNA and protein content provides a more complete definition of cell cycle position than DNA content alone.
Sequential vincristine, arabinosylcytosine and adriamycin in acute leukemia: Cytologic and cytokinetic studies
Authors: Riccardi Alberto , Mazzini Giuliano , Montecucco Carlomaurizio , Cresci Roberto , Traversi Egidio , Berzuini Carlo , Ascari Edoardo 
Published: August 2005

AbstractCytokinetic and cytocidal effects exerted on peripheral blood blasts by sequential administration of vincristine (VCR) 2 mg on day 1, arabinosylcytosine (Ara‐c) 50–60 mg/m2/12 hr from day (2–4), and Adriamycin (ADM, Farmitalia, Milan, Italy, 40–60 mg/m2 on day 5) have been examined in 22 courses of treatment performed on 12 patients with nonlymphoblastic and in 4 with lymphoblastic acute leukemia. In 4 patients, the bone marrow blasts were examined before and also after VCR‐Ara‐c administration. In vitro tritiated thymidine autoradiography and propidium iodide‐DNA flow cytometry were employed for kinetic studies. Blasts disappeared from blood with a median half time of 35 hr. After VCR‐Ara‐c administration, a significant increase in labeling index (LI) and in the aliquot of cells with DNA content between the diploid (2n) and the tetraploid (4n) values was observed in 80% of the courses in peripheral blood blasts and in all courses in bone marrow blasts. The median grain count over the labeled nuclei was decreased, and the 4n cell percentage and the bone marrow blast mitotic index did not increase. These findings suggest that the increase in the S phase fraction of blast population is due to cell synchronization. Increase in the S phase appears to heighten the cytocidal effect of ADM. The aliquot of the blasts cleared from blood after ADM were in fact related directly to the degree of labeling index increase observed during the previous administration of VCR and Ara‐c.
Rapid detection of Legionella pneumophila by flow cytometry
Authors: Ingram Marylou , Cleary Timothy J. , Price Brandon J. , Price Relf L. , Castro Albert 
Published: August 2005

AbstractLegionella pneumophila labeled with specific fluorescent antibody was detected in a suspension of organisms by means of flow cytometry. The presence of other microorganisms in the suspension did not interfere with the recognition of Legionella when present at concentrations of 104 to 105 cells per ml. These data suggest that flow cytometry may be useful for the detection of Legionella in environmental samples.
Chromosome sorting and DNA sequence localization
Authors: Lebo Roger V. 
Published: August 2005

AbstractThis article focuses on current techniques and possible future developments in chromosome isolation and sorting, and DNA analysis of sorted chromosomes. The strategy of subchromosomal gene mapping by chromosome sorting is outlined and a list of cell lines containing translocated chromosomes is provided which may be used to map genes to a single chromosome with a standard fluorescence activated cell sorter. The usefulness of this and other gene mapping methods for localizing unique DNA sequences and characterizing recombinant DNA libraries constructed from sorted chromosomal DNA is also discussed.
Analysis of ligand‐receptor interactions with the fluorescence activated cell sorter
Authors: Sklar Larry A. , Finney David A. 
Published: August 2005

AbstractThe binding of a fluorescent peptide to human neutrophils is analyzed with a fluorescence activated cell sorter. We examine steady‐state and kinetic features of the ligand‐receptor interaction (in the presence of unbound ligand) and we show that the number of receptors may be estimated without resorting to any external references for calibration. These methods are applicable to other fluorescent ligands with affinities > 108 M−1.
Flow cytofluorometric study of lipoprotein interactions with cultured endothelial cells
Authors: Preobrazhensky Sergey N. , Antonov Alexander S. , Perova Natalya V. , Sherbakova Inna A. , Samokhin Gennady P. , Gerasimova Elena N. , Repin Vadim S. , Smirnov Vladimir N. 
Published: August 2005

AbstractAccumulation of rhodamine B isothyocyanate‐conjugated low density lipoproteins (R‐LDL) in cultured endothelial cells from human umbilical cord was studied with a fluorescence activated cell sorter. R‐LDL uptake was blocked at 0°C, inhibited by addition of excess of nonlabeled low density lipoprotein, high density lipoprotein‐2 or high density lipoprotein‐3. High density lipoprotein‐2 was about twice as effective in inhibition of R‐LDL uptake as high density lipoprotein‐3. Endothelial cells that formed a contact‐inhibited monolayer lost the ability to incorporate R‐LDL via a receptor‐mediated pathway. Using R‐LDL, it was possible to distinguish cells with different levels of R‐LDL incorporation.
Two color light scattering indentifies physical differences between lymphocyte subpopulations
Authors: Otten Gillis R. , Loken Michael R. 
Published: August 2005

AbstractForward angle light scattering of two different wavelengths by cells in a flow cytometer was used to investigate physical differences between lymphocytes of different lineage, functional subclass and developmental stage. Correlation of the ultraviolet (UV: 351 nm and 364 nm) and 488 nm light scattering signals produced by lymphoid cells demonstrated that the two signals were not equivalent and that they placed different emphasis on the physical parameters characterizing lymphocytes. Both small T and B lymphocytes from peripheral lymphoid tissues and mitogenically activated large T and B lymphocyte blasts were discriminated by both wavelengths. Differences between the Lyt‐2 negative and Lyt‐2 positive T lymphocyte subsets were also apparent. Two color light scattering could also discriminate between immature thymocytes and mature peripheral T cells and between small bone marrow cells and mature peripheral B cells. In bone marrow an increase in UV light scattering coincided with the appearance of cell surface immunoglobulin on small cells. These data establish that two color light scattering is a sensitive probe for distinguishing cells of apparently similar morphology and that it can be used to study the physical changes that occur during lymphoid cell differentiation.
A new flow cytometric transducer for fast sample throughput and time resolved kinetic studies of biological cells and other particles
Authors: Kachel V. , Glossner E. , Schneider H. 
Published: August 2005

AbstractIn state of the art flow cytometric transducers, the cells are supplied through tubes. Passage through the tube and washing between different samples is time consuming and limits the number of samples that can be processed in a given time. This is a drawback particularly with automatic routine instruments. For kinetic studies in the time range of seconds, it is necessary to perform the cell reactions directly in the transducer in order to have a short delay between the suspension vessel where the cell reaction is in progress and the point of measurement. A new one parameter electrical sizing transducer without a particle supplying tube is described and compared with a conventional Metricell transducer. The cells are directly supplied from an exchangeable vessel to the measuring point in the transducer. The vessel which is an inexpensive mass produced product, serves as the injection tip for passing the cell suspension into the focusing flow path. There is no interconnected tube to delay or intermix the cells in the stage between the reaction in progress in the vessel and flow analysis. Delay times of only 1 second are achieved with the new transducer, and by supplying each sample with its own vessel subsequent samples are analyzed without the necessity of cleaning a cell supplying tube. In this way a high throughput of samples per time unit is achieved and time kinetic experiments in the time range of seconds can be performed. The design of a tubeless multiparameter Fluvo Metricell transducer is explained.
Slit‐scan flow cytometry: Separability properties of cell features
Authors: Mann R. C. 
Published: August 2005

AbstractA model is presented to compare the separability of cell populations described by features measured in low resolution slitscanning flow systems with their separability when the features are extracted from high resolution digitized cell images. The results show that although the accuracy of the feature measurements deteriorates for increasing slit width, this is not necessarily true for the discriminatory power of the features. Depending on their original position in the high resolution feature space, the cell populations may be located even farther apart in the space of low resolution slit‐scan features for reasonably small widths of the slit. The results presented with high resolution images of cells from gynecological specimens and simulated slit‐scan measurements can be explained by the model. For the features nuclear DNA content and diameter the abnormal populations are shifted closer to the normal populations in the slit‐scan simulations as compared to the high resolution measurements. The cell classifier errors rates are unacceptably high.
Quantification of the degree of cell spreading of human fibroblasts by semi‐automated analysis of the cell perimeter
Authors: Brugmans Mia , Cassiman Jean‐Jacques , Vanderheydt Luc , Oosterlinck André J. J. , Vlietinck Robert , Van Den Berghe Herman 
Published: August 2005

AbstractCell flattening and spreading on a substratum is of major importance in cellular and developmental biology. To study the mechanisms of cell spreading, quantitative and reproducible measures of the degree of cell spreading must be available.Normal human fibroblasts, spreading on a substratum, were fixed with glutaraldehyde, stained with acridine orange and photographed (×40) under a fluorescence microscope. The photonegatives (containing 10–30 cells) were scanned with a drum scanner and a complete picture containing 128 gray levels was constructed. Each cell contour was calculated with the use of a local threshold. The image and the superimposed cell contours were displayed on a television screen (16 gray levels) and errors were corrected interactively. With this system the spreading of normal human skin fibroblasts as a function of time could be quantified reproducibly. Compared to surface area or shape, the cell perimeter proved to be a very sensitive parameter of the degree of spreading. By using cell perimeter measurements, differences in the degree of spreading on various substrata could be quantified.
Flow cytometric analysis of factors which influence the BrdUrd‐Hoechst quenching effect in cultivated human fibroblasts and lymphocytes
Authors: Kubbies M. , Rabinovitch P. S. 
Published: August 2005

AbstractHuman fibroblasts and lymphocytes were grown in bromodeoxyuridine (BrdUrd) containing medium, harvested after 27–71 hours and stained with the fluorochrome Hoechst 33258. Parameters that influence the BrdUrd quenching effect of Hoechst fluorescence at a given pH and ionic strength of the staining solution were determined. The parameters were determined in order to obtain high resolution histograms with differentiation of each cell cycle compartment for noncycling cells and for cycling cells in the first and second cycle. The BrdUrd concentration was found to be the most significant determinant, but cell density, cell type, dye concentration, type of Hoechst stain and incubation temperature during staining also contribute to the modulation of fluorescence of BrdUrd substituted nuclei. Optimization of these factors is required in order to achieve complete and well resolved cell cycle histograms by the BrdUrd‐Hoechst flow cytometric technique.
Neutropenia: The accuracy and precision of the neutrophil count in leukopenic patients
Authors: Ross Dennis W. , McMaster Kitt 
Published: August 2005

AbstractNeutropenia (absolute neutrophil count < 500/μl) is a life threatening clinical state commonly seen in cancer and leukemia patients on intensive chemotherapy. The purpose of this investigation is to determine the accuracy and precision of the absolute neutrophil count in these patients using two methods: (1) the percentage of neutrophils as determined by a 100 cell manual differential multiplied by the white blood cell count (NEUT‐M), and (2) the absolute neutrophil count determined directly by automated flow cytometry using the Hemalog‐D automated white cell differential counter (NEUT‐D) Technicon Instruments Corp., Tarrytown, NY. The coefficient of variation (cv) for repeated measurements was dependent on absolute neutrophil count. For manual determinations, the cv was 5% at 5000/μl, 18% at 500/μl, and 42% at 50/μl. For the cytometry method the cv was 2.5% at 5000/μl, 8% at 500/μl, and 17% at 50/μl. The accuracy of flow cytometric differential neutrophil counts using the Hemalog‐D system was found to be equivalent to the manual differential count. The precision, however, was more than twice that of the manual white cell differential count. In the neutropenic patient this analytical improvement was clinically useful as demonstrated by sequential observation of daily neutrophil counts.
Distinction between 5‐bromodeoxyuridine labeled and unlabeled mitotic cells by flow cytometry
Authors: Darzynkiewicz Zbigniew , Traganos Frank , Melamed Myron R. 
Published: August 2005

AbstractExponentially growing Friend leukemia cells are exposed to 5‐bromodeoxyuridine (BrdUrd) for the time period equivalent to one generation. After fixation and incubation with RNase, DNA in situ is partially denatured by acid and the cells are stained with acridine orange (AO). Staining with AO under these conditions reveals the extent of denatured versus double stranded DNA and enables one to distinguish mitotic from interphase cells. It is observed that all BrdUrd treated cells, regardless of cell cycle phase, have decreased both green and red fluorescence. This finding suggests that BrdUrd interacts with AO not only in the complexes of the dye with double stranded DNA, but also with the single stranded biopolymer. The BrdUrd‐attributed suppression of cell fluorescence is large enough to separate totally BrdUrd labeled from unlabeled mitotic populations. The combination of these two flow cytometric techniques, one which allows discrimination between interphase and metaphase cells and the other which allows further subdivision of metaphase cells into those which have incorporated BrdUrd and those which have not, provides an alternative to the autoradiographic procedure necessary for obtaining the fraction of labeled mitoses.
A video‐computer for the chronotropic and inotropic measurements of the beating of cultured heart cells
Authors: Harary Isaac , Wallace Garn , Bristol Greg 
Published: August 2005

AbstractA video‐computer system has been developed to measure the chronotropy and inotropy of cultured heart cells. The motion of the cell is followed by recording of the changes of light intensity from the edge of a beating cell. With this system the velocityof contraction and relaxation, the time to peak contraction, relaxation time and the displacement of the cell in culture can be measured for the first time. Also, the rate of beating can be measured beyond the limits set by visual counting. With the application of this technique to the cultured heart cell system we have found that norepinephrine increases the velocity of relaxation thus reducing the ratio of contraction velocity to relaxation velocity, and reduces the twitch time. Increased external calcium, on the other hand, has little effect on either the velocity of contraction or relaxation but, like norepinephrine, decreases the twitch time.
Chromosome analysis by high illumination flow cytometry
Authors: Bartholdi Marty F. , Sinclair Douglas C. , Cram L. Scott 
Published: August 2005

AbstractFluorescence measurements from metaphase chromosomes of the Chinese hamster, stained with propidium iodide excited at high illumination irradiance, completely resolve each chromosome type. The measurements are performed in a specially designed flow cytometer that achieves high irradiance (4 MW/cm2) by using high power laser output (2 W at 488 nm) focused to small spot size (1% irradiance variation over 2 m̈m). The coefficient of variation of each chromosome peak is near 1.5%.Saturation of the fluorescence transition and photobleaching, two consequences of high irradiance, are shown to occur. Even with a nonlinear dependence of fluorescence upon illumination irradiance, fluorescence retains a proportional response to chromosome type; each chromosome peak maintains a consistent ratio to the others at every irradiance. No perturbation of fluorescence by the optical or geometrical properties of the chromosomes is evident.The advantages of high irradiance illumination are an increase in fluorescence sufficient to reduce the statistical error in photoelectron number to a low level and reduced influence of laser power fluctuations and variable chromosome flow trajectories on the precision. These benefits improve the resolution of chromosome analysis by flow cytometry, particularly the resolution of smaller chromosomes.
Differentiation of HL‐60 cells: Cell volume and cell cycle changes
Authors: Zucker Robert M. , Whittington Karen , Price Brandon J. 
Published: August 2005

AbstractHL‐60 promyelocytic leukemic cells can differentiate into more mature myeloid cells with the addition of dimethylsulfoxide, butyric acid or retinoic acid and can differentiate into macrophages with the addition of phorbol ester 12‐0‐tetradecanoylphorbol‐13‐acetate (TPA). After the addition of an inducer, the HL‐60 cell volume shows a daily decrease while the cell number increases at a rate similar to the untreated control cells. Flow cytometry measurements show an increase in G1 cells and a decrease in S cells after day 1. Since the generation time is constant, the data suggest that the length of time spent in the different cell cycle stages has changed during differentiation.Within 3 hours after the addition of TPA to HL‐60 cells, selective adhesion of G1 cells occurs. Smaller sized cells are recovered from the flask bottom and larger sized cells are recovered from the supernate. Flow cytometric analysis reveals a G1 and S block in cells obtained from both the supernatant and from the flask bottom. After 1 day of TPA incubation, there is preferential adhesion of G1 and G2 cells with the nonadherent cells being primarily in the S and G2 cell cycle stages and undergoing a cell cycle traverse.