bluuebunny/crossref_metadata_2025_split huggingface dataset:
Centrifugal separation of cells in sputum specimens from patients with adenocarcinoma
Authors: Pressman Norman J. , Albright Craig D. , Frost John K. 
Published: August 2005

AbstractA Ficoll density gradient centrifugation technique was used to separate fixed cells from the sputa of patients with bronchogenic adenocarcinoma. The selective enrichment of leukocytes, squamous or cancerous cells was achieved while retaining the diagnostically significant cell morphologic features. This technique is shown to typically eliminate most of the leukocytes (96.9%), macrophages (86.7%), squamous cells (70.0%) and necrotic debris from specimen fractions containing the majority of cancerous cells. The maximum purity of cancer cells (14.6%) occurs in high density (ρ=1.135 g/ml) gradient fractions and results in an average 12.2‐fold enrichment for cancer cells in contrast to their relative frequency of occurrence in unprocessed specimens. Differential cell count analyses of serial density centrifugation fractions show that this technique produces comparable enrichment rates for material from bronchogenic adenocarcinoma and squamous cell carcinoma.
Identification of mitogen responding lymphocytes by fluorescence polarization
Authors: Udkoff Ranon , Chan Sandra , Norman Amos 
Published: August 2005

AbstractMeasurements of the intensity and polarization distributions of fluorescein fluorescence in human lymphocyte populations show changes within minutes after exposure of the cells to the mitogens phytohemagglutinin and Concanavalin A. The distributions of polarization, which before mitogen exposure show essentially a single peak, after exposure develop a second peak at a lower value of polarization. Simultaneously, the intensity distributions show a shift to higher levels of intensity. These shifts can be modeled on the basis of a subpopulation of lymphocytes responding to mitogen. Interpretation of the results is complicated by many factors that may influence the shape of the polarization distributions. In particular we show that the measurements are sensitive to the concentrations of phytohemagglutinin, Concanavalin A, Ca++, K+, fluorescein diacetate, the incubation time and the specific donor. Nevertheless, fluorescein fluorescence measurements provide a rapid and sensitive method for studying the physiology of lymphocytes and for identifying responding lymphocyte subpopulations.
Rapid analysis of drug effects on the cell cycle
Authors: Darzynkiewicz Zbigniew , Traganos Frank , Xue Shaobai , Staiano‐Coico Lisa , Melamed Myron R. 
Published: August 2005

AbstractUsing a flow cytometric technique to analyse DNA content and chromatin structure simultaneously, the following parameters of cell cycle progression were estimated in control and drug‐treated L1210 cell cultures: (a) the kinetics of cell exit from the G1 phase; (b) the probability of cell exit from the indeterminate portion of the G1 phase, measured as the half‐time of cell residence in that state; (c) the duration of the deterministic portion of G1 phase; (d) the rates of cell transit through selected “windows” in S phase; (e) the rate of cell entrance into mitosis; (f) the mean duration of the cell cycle (Tc). These parameters are obtained in a single stathmokinetic experiment from measurements of individual samples withdrawn at 30 min‐1 hr intervals from Vinblasatine‐treated cultures. In the same experiment mitotic indices are obtained with high statistical accuracy, and may be used to determine the terminal point of drug action. In addition to cell cycle analysis the method makes it possible to detect drug‐induced changes in nuclear chromatin that are manifested by varying sensitivity of DNA in situ to denaturation by acid. Such changes were found to be associated with defective chromatin condensation, altered histone modifications or intercalation of the drugs into DNA. Using this technique the effects of sodium n‐butyrate and two new antitumor drugs on L1210 cells were investigated.
Texture of white blood cells expressed by the counting densitogram,
Authors: Bins M. , Landeweerd G. H. , Gelsema E. S. , van Montfort L. H. , Halie M. R. 
Published: August 2005

AbstractThe counting of particles and holes in white blood cells during thresholding at different gray levels results in a histogram, the counting densitogram, which contains information about granularity. Parameters describing the shape of this histogram appear to be sufficiently characteristic for the five normal white blood cell classes to allow a 84% correct discrimination between them. This method to quantitate granularity could be valuable for the analysis of cell texture and therefore, when used in combination with geometrical and density histogram parameters, could contribute to the results of morphometric discrimination between other than normal white blood cells.
Modular computer programs for flow cytometry and sorting: The LACEL system
Authors: Salzman G. C. , Wilkins S. F. , Whitfill J. A. 
Published: August 2005

AbstractA computer‐based data acquisition, display and processing system for flow cytometers has been developed. The Los Alamos Cell Analysis (LACEL) programs and electronic hardware provide the capability to acquire list mode or histogram data for up to eight parameters and control bidirectional sorting based on up to four parameters for each direction. The programs described in this paper also enable the display of single parameter and bivariate histograms and the graphical manipulation of the list mode data. The electronic hardware is described in a companion paper.
Modular electronics for flow cytometry and sorting: The LACEL system
Authors: Hiebert R. D. , Jett J. H. , Salzman G. C. 
Published: August 2005

AbstractLACEL is a newly developed, fast, general‐purpose data acquisition and processing system for flow cytometric applications. The system's modular electronics allows flexibility in system configurations. The system can process as many as eight input analog parameters and can transfer 16‐bit words between the user's electronics and the computer with standard input/output interfaces. The system's 8‐fold coincidence logic capability can be set to operate with the noncoincidental timing that may occur in multiparameter flow measurements. As many as four parameters can be used to establish amplitude and timing criteria for each of two sorting directions. Two experiments can be on line with the computer at one time.
Measurement of DNA synthesis by flow cytometry
Authors: Noguchi Philip D. , Johnson Joyce B. , Browne Walter 
Published: August 2005

AbstractCells were stained for DNA content with Hoechst 33258 combined with propidium iodide and analyzed on an epi‐fluorescence flow cytometer. Scatterplots of red versus blue fluorescence of control cells showed a straight line indicating that both dyes were measuring proportional amounts of cellular DNA. Scatterplots of cells incubated with the thymidine analog bromodeoxyuridine, however, showed a displacement from the control straight line that increased with longer exposure time to bromodeoxyuridine. These results suggest that bromodeoxyuridine incorporation in DNA can be detected by flow cytometry.
The look‐up table: A classifier for cell sorters
Authors: Koper Ger J. M. , Christiaanse Johan G. M. 
Published: August 2005

AbstractCurrently used classifiers for flow cell sorters are described and the look‐up table is introduced as such. An experimental setup of a look‐up table classifier added to a commercially available cell sorter, under control of a microcomputer is described. The contents of the look‐up table are obtained from contrours of regions of interest. These regions are defined by the user who designates the areas on a video color display of the bivariate flow data. Since most cell clusters form elliptic or ovoid shapes in a multi‐dimensional feature space this method enables a better matching of window shapes to cluster outlines, compared to conventional sort decision circuitry.
The fluorescence intensity of propidium iodide bound to DNA depends on the concentration of sodium chloride
Authors: Martens Anton C. M. , van den Engh Gerrit Jan , Hagenbeek Anton 
Published: August 2005

AbstractWhile performing DNA analysis with propidium iodide using the FACS‐II cell sorter, it was noted that the fluorescence intensity was not constant during the measurements. When different sheath and sample fluids were used, the fluorescence intensity of a given cell population increased or decreased during the measurement, depending on the concentration of sodium chloride in the fluids. By selecting the appropriate sheath and sample fluid combination, the drift in fluorescence intensity can be avoided.
Flow cytofluorometric analysis of the nuclear division cycle of Physarum polycephalum plasmodia
Authors: Murphy Robert F. , Daban Joan‐Ramon , Cantor Charles R. 
Published: August 2005

AbstractThe nuclear cycle kinetics of Physarum polycephalum plasmodia were examined using flow cytofluorometry. The dyes Hoechst 33342 and propidium iodide were used to stain the DNA of isolated nuclei. In asynchronously growing microplasmodia, S phase consists of 13–15% of the nuclear division cycle time. Nuclei isolated from individual macroplasmodia, which have previously been demonstrated to divide in synchrony, were shown to be less synchronized during late S phase than during mitosis. The results obtained demonstrate the feasibility of flow cytometric measurement of the properties of nuclei isolated from a single cell.
Cell cycle analysis by combining the 5‐bromodeoxyuridine/33258 hoechst technique with DNA‐specific ethidium bromide staining
Authors: Böhmer Ralph‐M. , Ellwart Joachim 
Published: August 2005

AbstractCells were grown in 5‐bromodeoxyuridine(BrdUrd)‐containing medium, harvested and stained with a combination of 33258 Hoechst and ethidium bromide for analysis in a two‐parametrical flow cytometer. Both fluorescences were excited by UV laser light, and ethidium bromide was additionally excited by energy transfer from the Hoechst dye. The separation of the two fluorescences proved to be excellent, the projected histograms showing a quality comparable to the quality obtained by single dye staining. The ethidium bromide fluorescence gives information as to where the cell is located within the cycle of DNA replication, while the BrdUrd‐quenched Hoechst fluorescence gives information as to where in the cycle the cell was located at the beginning of BrdUrd incorporation. In this way information is obtained concerning the distance a cell traveled through the cycle during the BrdUrd incubation time. This method may become a powerful tool in many investigations dealing with cell cycle perturbations in culture.
Simplified method for DNA and protein staining of human hematopoietic cell samples
Authors: Crissman Harry A. , Van Egmond Jan , Holdrinet Robert S. , Pennings Arie , Haanen Clemens 
Published: August 2005

AbstractA rapid reproducible method yielding high resolution analysis of DNA and protein in human hematopoietic cell samples has been developed by modification of the propidium iodide and fluorescein isothiocyanate procedure. Cell staining involves sequential addition of each reagent (RNase, fluorescein isothiocyanate and propidium iodide) to ethanol‐fixed cells and requires no centrifugation steps. Stained cells are analyzed in the reagent solutions. Analysis of bone marrow samples from multiple myeloma patients showed mixed normal and aneuploid populations with a major portion of the aneuploid cells having a significantly higher protein content. This approach permitted differential cell cycle analysis of normal and the aneuploid populations.
Flow cytometric estimation of DNA and RNA content in intact cells stained with hoechst 33342 and pyronin Y
Authors: Shapiro Howard M. 
Published: August 2005

AbstractThe addition of RNA content estimation to flow cytometric measurement of DNA content provides valuable information concerning cells' transitions between quiescent and proliferative states. Equilibrium staining methods employing acridine orange have been used for DNA/RNA content measurement but are difficult to apply to intact cells and impractical for use in conjunction with fluorescent antibodies or ligands for demonstration of cell surface structures. I have used a combination of Hoechst 33342 (HO342) and pyronin Y (PY) to stain intact cells for DNA/RNA content estimation with a dual source flow cytometer using UV and blue‐green or green excitation, measuring HO342 fluorescence at 430–470 nm and PY fluorescence at 590–650 nm. Results obtained with cultured cells and stimulated lymphocytes are in good agreement with those obtained using acridine orange for DNA/RNA staining; about half of the PY fluorescence can be removed from ethanol‐fixed cells stained with HO342 and PY by RNAse digestion. The HO342/PY method can be combined with fluorescein immuno‐fluorescence for detection of cell surface markers. HO342 can be combined with other tricyclic heteroaromatic dyes for DNA/RNA estimation; the combination of HO342 and oxazine 1 can be excited in a dual source instrument using a mercury arc lamp and a helium‐neon laser. The staining procedure is simple; cells in medium are incubated with 5 μM HO342 at 37°C for 45 min, 5 μM PY (or oxazine 1) is then added and cells are analyzed without washing after an additional 45 min incubation. Suitability of these dye combinations for vital cell staining and sorting remains to be determined.
Measurement of the distribution of time intervals between cell passages in flow cytometry as a method for the evaluation of sample preparation procedures
Authors: Lindmo Tore , Fundingsrud Kåre 
Published: August 2005

AbstractIt is expected that the time sequence of cells passing through the sensing region of a flow cytometer should follow the statistics of a Poisson process. Thus, measurement of time intervals between passages of fluorescent microspheres and cells stained with mithramycin demonstrated the negative exponential distribution characteristic of such a process. However, analysis of cells stained with fluorescein‐iso‐thiocyanate showed marked deviations from a negative exponential distribution of time intervals. The distribution had an additional component due to time intervals with mean value about 60 times shorter than the population mean, and in certain cases more than 50% of the cells were registered with such short time intervals. This percentage could, however, be reduced to acceptable levels by modifications of the sample preparation procedure. Measurement of the distribution of time intervals between cell passages is proposed as a method for the evaluation of possible improvements in sample preparation procedures.
Mathematical evaluation of two parameter flow cytometric histograms
Authors: Scholz Karl‐U. 
Published: August 2005

AbstractA general procedure was developed to evaluate two‐parameter flow cytometric data. These data usually show overlapping distributions representing different subpopulations. To calculate the fractions of cells in the various subpopulations, the maximum likelihood method is used, assuming an unknown number of Gaussian distributions with constant coefficient of variation in the histogram. A test on simulated data shows that Gaussians can be separated clearly by the procedure if the distance between their mean values is larger than twice the maximum standard deviation. The analysis of different measurements of double‐stained (DNA/protein) cultured cclls out of the same pool yield the same fractions in the phases of the cell cycle with acceptable error rates. To simulate samples with different fractions in the phases of the cell cycle, defined mixtures of proliferating and resting cells of the same type were prepared and measured for DNA and cell size. The calculated fractions are consistent with the expected variation of G1, S and G2 + M fractions depending on the mixture ratio.
The effect of hexamethylene‐bis‐acetamide on multiparameter analysis of friend leukemia cells
Authors: Mishal Z. , Fourcade A. , Tapiero H. 
Published: August 2005

AbstractFriend leukemia cells were induced to differentiate by hexamethylene‐bis‐acetamide (HMBA). The relationship between cell growth cell volume distribution, fluorescence intensity and fluorescence anisotropy of the membrane probe 1,6 diphenyl 1,3,5 hexatriene (DPH) was analyzed in differentiated and undifferentiated cells with the aid of the fluorescence activated cell sorter (FACS II). The induction of a differentiated state was associated with a decrease in cell volume and an increase of fluorescence anisotropy. The inhibition of this induction by dexamethazone prevented the decrease of cell volume without affecting the increase of fluorescence anisotropy. We conclude therefore that the high degree of anisotropy is not correlated to the differentiated state nor with the volume of the cells.
G2‐delay after irradiation with α‐particles as studied in synchronized cultures and by the bromodeoxyuridine‐33258H technique
Authors: Hieber L. , Beck H.‐P. , Lücke‐Huhle C. 
Published: August 2005

AbstractDivision delay of mouse L‐929 fibroblasts after α‐irradiation is due to a pronounced lengthening of their G2‐phase. Experiments on synchronously and asynchronously growing cultures revealed a cell cycle phasedependent sensitivity of this effect: Cells irradiated in G2 or at the Gl/S border suffered a longer G2‐delay than cells irradiated at mid‐ or late‐S. Progression through G2 was nearly normal at doses up to 0.3 Gy if cells were exposed during Gl phase.
DNA content and kinetic characteristics of non‐Hodgkin's lymphoma: Determined by flow cytometry and autoradiography
Authors: Costa Aurora , Mazzini Giuliano , Bino Giacinta Del , Silvestrini Rosella 
Published: August 2005

AbstractThe determination of DNA content and [3H]thymidine labeling index was carried out on malignant lymph nodes from 74 patients with non‐Hodgkin's lymphoma. Analysis of cellular DNA content was performed using propidium iodide as DNA‐specific fluorescence dye. The ploidy was expressed as the DNA ratio between the relative DNA content of the human lymphoid G0/1 cells to that of chicken red blood cells. Forty‐five of the 74 non‐Hodgkin's lymphomas (61%) were aneuploid populations and the majority of these (91%) showed a hyperdiploid DNA content. A higher frequency of aneuploidy (72%) was observed in tumors with unfavorable histology than in those with a favorable histology (55%). Moreover, among aneuploid lyrophomas heterogeneous populations were observed in 24% of the cases. The evaluation of flow cytometric data using Fried's deconvolution procedure showed no statistically different frequency of G0/1, S and G2 + M cells between the two groups of tumors with favorable and unfavorable histology. On the contrary, a statistically different frequency of G0/1 and S cells was observed between the two groups of tumors with low and high labeling indices (P < 0.01). A correlation was found between autoradiographic and flow cytometric determination of S phase cells (P < 0.001).
High resolution DNA content measurements of mammalian sperm
Authors: Pinkel D. , Lake S. , Gledhill B. L. , Van Dilla M. A. , Stephenson D. , Watchmaker G. 
Published: August 2005

AbstractThe high condensation and flat shape of the mammalian sperm nucleus present unique difficulties to flow cytometric measurement of DNA content. Chromatin compactness makes quantitative fluorescent staining for DNA difficult and causes a high index of refraction. The refractive index makes optical measurements sensitive to sperm head orientation. We demonstrate that the optical problems can be overcome using the commercial ICP22 epiillumination flow cytometer (Ortho Instruments, Westwood, MA) or a specially built cell orientating flow cytometer (OFCM). The design and operation of the OFCM are described. Measurements of the angular dependence of fluorescence from acriflavine stained rabbit sperm show that it is capable of orienting flat sperm with a tolerance of ± 7 degrees. Differences in the angular dependence for the similarly shaped bull and rabbit sperm allow discrimination of these cells. We show that DNA staining with 4‐6 diamidino‐2‐phenylindole (DAPI) or an ethidium bromide mithramycin combination allows resolution of the X and Y populations in mouse sperm. They have also been successful with sperm from the bull, ram, rabbit, and boar. Reliable results with human sperm are not obtained. The accuracy of the staining and measurement techniques are verified by the correct determination of the relative DNA content of these two populations in sperm from normal mice and those with the Cattanach [7 to X] translocation. Among the potential uses of these techniques are measurement of DNA content errors induced in sperm due to mutagen exposure, and assessment of the fractions of X and Y sperm in semen that may have one population artifically enriched.
An epiilluminator/detector unit permitting arc lamp illumination for fluorescence activated cell sorters
Authors: Koper Ger J. M. , Bonnet Jan , Christiaanse Johan G. M. , Ploem Johan S. 
Published: August 2005

AbstractThe application of arc lamps to flow cytometers is discussed and epiillumination for jet‐in‐air cell sorters is introduced. An epiilluminator/detector unit equipped with a mercury arc lamp constructed for a commercially available cell sorter is described. Experiments in which laser and mercury arc lamp illumination were compared show that the signal‐to‐noise ratio for the arc lamp illumination is predominantly limited by shot noise from constant light backgrounds due to reflected excitation light and ambient light. Arc lamp illumination can be used for the sorting of highly fluorescent objects such as cells stained for DNA by for example: ethidium bromide, propidium iodide, or the Hoechst dyes. The simultaneous employment of mercury arc and laser light sources as an inexpensive dual wavelength system is discussed.
EMOSS: An epiillumination microscope objective slit‐scan flow system
Authors: Weller Laura A. , Wheeless Leon L. 
Published: August 2005

AbstractAn epiillumination microscope objective slit‐scan flow system has been fabricated utilizing two dimensional slit scanning with hydrodynamic sample stream focussing. Low resolution (4 μm) analysis of cellular fluorescence is facilitated by the definition of a stabilized flow plane through hydrodynamic focussing. Coincidence of the region of stabilized flow with the focal plane of the microscope objective will allow for the collection and subsequent imaging of fluorescence from cells oriented along this plane. Two orthogonal slit‐scan contours are generated as a cell traverses the excitation region. It is hoped that the need for a three dimensional system will be precluded by preferential orientation of the cells in the region of stabilized flow. Cellular fluorescence is collected by a high numerical aperture epiillumination optical system and imaged onto two orthogonal slits. Two photomultiplier tubes are used to detect fluorescence.It is anticipated that the epiilumination microscope objective slit‐scan flow system will be used with a variety of fluorescent stains and markers, as well as extended to the research of light scattered by cells. (Steen, H. B., Cytometry 1:26–31, 1980).