bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proteins from metaphase chromosomes treated with fluorochromes
Authors: Wray Wayne , Wray Virginia P. 
Published: August 2005

AbstractThe biochemical composition of any isolated organelle is affected by the agent(s) to which it has been exposed during the isolation and purification procedures. Many agents are known to extract molecular components either selectively or nonselectively. The protein composition of isolated chromosomes exposed to fluorochromes must be examined before proceeding to the biochemical analysis of the proteins from individual chromosomes purified by flow cytometry techniques. We have examined the poly‐acrylamide gel electrophoresis protein profiles from metaphase chromosomes exposed to the fluorochromes and staining conditions commonly used for flow cytometry. We find that the electropherograms of the protein of metaphase chromosomes which have been exposed to various fluorochromes are indistinguishable from controls. The analysis of proteins from individual chromosomes sorted by flow cytometry can now be undertaken.
Enhanced light collection in a flow cytometer
Authors: Fox Michael H. , Coulter James R. 
Published: August 2005

AbstractA modified flow cell in a conventional flow cytometer is described. The refraction of light in the flow cell‐to‐air interface is analyzed. The analysis shows that much of the light that can be collected is refracted out of the collection optics. The efficiency of light collection is doubled by the addition of a plano‐convex lens to the flow cell. Also, more stable operation of the flow cell is achieved with the addition of a secondary sheath.
Further developments of a microscope‐based flow cytometer: Light scatter detection and excitation intensity compensation
Authors: Steen Harald B. 
Published: August 2005

AbstractA microscope‐based flow cytometer, which is based on a new flow system, has been extended to include light scatter detection, dual parameter fluorescence analysis, and a device which compensates for variations in excitation light intensity. A dichroic mirror splits the fluorescence into two spectral components that are further purified by additional filters situated in front of the photomultiplier tube detectors (PMT). Light scatter detection is obtained by a dark field configuration. An objective focuses the scattered light emitted within the dark field onto an adjustable slit in front of a PMT. Resolution of light scatter histograms of 1.5‐m̈m latex spheres is about CV = 2.5%. Dual parameter analysis revealed a linear correlation between the light scatter signal and fluorescence of cells stained with fluorescein isothiocyanate, indicating that the light scatter signal is closely proportional to cell dry mass. The instrumental light scatter, which is proportional to the excitation light intensity, gives rise to a DC signal. This signal regulates the fluorescence signal amplifiers so that these signals are compensated for fluctuations in the excitation light intensity.
The kinetics of the formation of a G2 block from tritiated thymidine in phytohemagglutinin‐stimulated human lymphocytes
Authors: Pollack A. , Bagwell C. B. , Irvin G. L. , Jensen J. A. 
Published: August 2005

AbstractFlow cytometry (FCM) was used to monitor the radiation effects promoted by incorporated tritiated thymidine (3H‐TdR) on phytohemagglutinin (PHA)‐stimulated human peripheral blood lymphocytes stained with propidium iodide (PI). Lymphocyte microcultures were continuously labeled or pulse‐labeled for various periods of time with different 3H‐TdR concentrations. Two types of DNA histogram analyses wer performed on unperturbed and 3H‐TdR perturbed lymphocytes. The data analyses consisted of statistical analyses between averaged groups of histograms (nonparametric analysis) and cell cycle analyses (parametric analysis) to determine the percentages of cells in G0 + G1, S and G2 + M. The results showed that (a) 3H‐TdR when added to proliferating lymphocytes under certain conditions (both short‐term continous and pulse‐labeling) caused a highly significant increase in the proportion of tetraploid (4C) cells by FCM, (b) the increase in the proportion of 4C cells represented a block in G2 and (c) the relative increase in the percentage of 4C cells was proportional to 3H‐TdR incorporation which was proportional to labeling time and concentration. Therefore, it was concluded that short labeling times be used to minimize adverse radiation effects when 3H‐TdR is used to assay substances affecting lymphocyte proliferation or in the estimation of cell cycle time.
The tradeoff of cell classifier error rates
Authors: Castleman Kenneth R. , White Benjamin S. 
Published: August 2005

AbstractIn gynecologic cytodiagnosis it is generally agreed that specimen false negative errors are more serious than false positives. When classifying individual cells, however, it is not obvious how one should adjust the parameters that control the two cell error rates. In the case where a specimen classifier follows a cell classifier, one can calculate the sample size required to achieve specified overall performance. This analysis shows that for the small abnormal cell proportions encountered in cervical cytology, cell false positives should be kept so low that a substantial portion of the abnormal cells are missed.
An optical model for fluorescence of mammalian sperm in flow cytometry
Authors: Kerker M. , Wang D.‐S. , Chew H. W. 
Published: August 2005

AbstractWhen flat sperm heads that have been stained to fluoresce are examined in a flow cytometer, unexpectedly, skewed pulse height distributions are obtained despite the apparent homogeneity of the samples. This anomaly has been ascribed to an optical artifact that arises when the cells are oriented in flow. We have extended our model for fluorescent scattering to spheroids and here explore some aspects for oblate spheroids which serve to model sperm heads. Although computational limitations have restricted these studies to oblate spheroids about 1.5 μm in diameter and an eccentricity of 0.1, the results clearly show effects of particle size, shape, optical properties and particularly of orientation on the differential scattering cross‐sections. This plethora of information contained in the fluorescent signals may suggest further experiments.
Estimation of the performance of an Array‐Processor oriented system for automatic pap smear analysis
Authors: Abmayr Wolfgang , Gais Peter , Rodenacker Karsten , Burger Georg 
Published: August 2005

AbstractThe rapid progress in computer technology makes possible the automatic analysis of thousands of cells on a slide in the field of automatic uterine cancer cytology. Our approach starts with the high‐resolution scanning of visually selected and classified single cells determining the training set for discriminant analysis. On the basis of more than 15 morphologic and textural features measured, correct classification results of 95% are reached. Our aim is to speed up our image processing system by means of an Array‐Processor, the model AP 120 B from Floating Point Systems. In this study a realistic time estimation of the scanning, segmentation, feature extraction and classification of about 40,000 cells on a slide is performed.
Field test results using the BioPEPR cervical smear prescreening system
Authors: Zahniser D. J. , Oud P. S. , Raaijmakers M. C. T. , Vooys G. P. , Van de Walle R. T. 
Published: August 2005

AbstractBioPEPR is a cathode ray tube scanning device that has been developed for the prescreening of cervical smears. Cervical samples are collected in suspension, syringed, counted and spread across a microscope slide. Feulgen‐Thionine with Congo Red is used as the staining procedure. Fields of 6 × 8 mm are scanned at 1 μ resolution, using an intermediate photographic step. Morphologic parameters of the cells are measured, as called for by a hierarchical decision strategy. Analysis speed is currently about 4 min per smear; improvements of at least a factor of four are expected. A field test of BioPEPR is being undertaken in cooperation with a local population screening program. In the study two smears are made from each woman; the first is prepared according to the Papanicolaou technique while the second is prepared and stained according to the BioPEPR methods. In addition to smears from the population screening program a number of possibly abnormal smears are obtained from several gynecological clinics. To date approximately 3500 “second” smears have been analyzed by the BioPEPR system. The results show a missed positive rate on the order of a few percent (no missed positives were more severe than a slight dysplasia), and a false alarm rate of about 24%. A further analysis of the age distribution of the false alarm rate shows that a large proportion came from women above the age of 50; the false alarm rate is about 20% for women under the age of 50.
A design for a real‐time fluorescence polarization computer
Authors: Stewart S. S. , Miller R. G. , Price G. B. 
Published: August 2005

AbstractWe have developed hardware components for our flow cytometer cell sorter which can perform real‐time calculations of either fluorescence polarization (FP) or anisotropy on a cell‐by‐cell basis and which can provide gating signals for the sorting of these cells into two populations. Artificial FP measurements, using electronic pulses varied over a 40dB range, were used to evaluate the computer's useful dynamic range. Real FP measurements, using human peripheral blood lymphocytes stimulated with phytohemagglutinin and labeled with fluorescein diacetate in saline, are presented to allow comparison with earlier work.
Flow cytometric analysis of the effect of 5‐bromodeoxyuridine on mouse teratocarcinoma cells
Authors: Swartzendruber Douglas E. , Travis Gayle L. , Martin John C. 
Published: August 2005

AbstractSeveral flow cytometric techniques were used to study the effects of 5‐bromodeoxyuridine (BrdUrd) on the growth and differentiation of mouse teratocarcinoma cells. The teratocarcinoma system mimics embryogenesis, and the stem cells of this tumor, termed embryonal carcinoma (EC) cells, spontaneously differentiate in vitro to progeny that are morphologically, biochemically and biologically distinct from the EC cells. When cultures of EC cells were treated with 30 μM BrdUrd, a pleiotropic response was observed; i.e., certain parameters mimicked spontaneous differentiation but occurred 2–3 times more rapidly while others were inconsistent with, or diametric to, spontaneous differentiation. In one line of diploid EC cells in which tetraploidy accompanies spontaneous differentiation, the BrdUrd accelerated the appearance of the tetraploid population. Analysis of cell cycle distributions during the course of the BrdUrd treatment showed that virtually all of the cells had cycled 2 or more times and incorporated BrdUrd into both strands of DNA. Multiangle light‐scattering and electrical impedance analyses indicated that with respect to these two parameters, cultures treated with BrdUrd for 3 days resembled spontaneously differentiating cultures of 6–8 days. However, BrdUrd treatment dit not induce increases in the kinetics of esterase (EC3.1.1.) activities in teratocarcinoma cells that normally accompany spontaneous differentiation. Analysis of alkaline phosphatase (APase) EC (3.1.3.1.) activities showed that, unlike the decrease in APase activities which accompany spontaneous differentiation, BrdUrd Treatment causes an increase in APase activities.
Intracellular binding of fluorescein in lymphocytes
Authors: Meisingset Knut K. , Steen Harald B. 
Published: August 2005

AbstractThe fluorescence characteristics of intracellular fluorescein, formed by hydrolysis of fluorescein diacetate in peripheral human lymphocytes, were studied by fluorometry on cell suspensions and compared to those of albumin bound and free fluorescein in solution. The absorption and fluorescence spectra of both intracellular fluorescein and fluorescein in aqueous solutions of albumin and glycerol were red shifted by 2–10 nm as compared to the spectra of fluorescein in phosphate buffered saline. The fluorescence polarization (P) of both intracellular fluorescein and a mixture of albumin‐bound and free fluorescein showed a decrease towards low emission wavelengths and an increase toward high excitation wavelengths. The results were found to be consistent with a simple model assuming that part of the intracellular fluorescein is dissolved in the aqueous phase of the cytoplasm, giving P < 0.1, while the rest is bound to macromolecules, giving P = 0.33. The fraction of bound intracellular fluorescein was estimated to be about 70%. Fluorescein was found to bind with higher affinity and more rigidly (P = 0.43) to albumin than to intracellular macromolecules in general.
Correlation between cytometric features and mitotic frequency in human breast carcinoma
Authors: Stenkvist Björn , Bengtsson Ewert , Eriksson Olle , Jarkrans Torsten , Nordin Bo , Westman‐Naeser Sighild 
Published: August 2005

AbstractAn evaluation of cytometric features of 142 human breast cancers was performed. Twenty‐two cytometric features describing density, structure and shape were correlated with mitotic frequency and labeling index of some of the tumors and with the observed recurrence rate of the tumors within 3 years after removal of the breast. A new cytometric measure was also created by combining the four features most strongly correlated with mitotic frequency of the tumors. It was found that the variance of the nuclear area was the feature that was most strongly correlated with mitotic frequency and recurrence rate. No new cytometric measure created by combining the four features most strongly correlated with mitotic frequency, correlated as well as variance of nuclear area even though the four features were optimized by multiple regression analysis for their correlation with mitotic frequency.
Flow cytometric probes of early events in cell activation
Authors: Shapiro Howard M. 
Published: August 2005

AbstractBy now, it's well established that the surface of a cellContains transmembrane proteins which, on binding ligands, tellThe biochemical computer inside what to doWithout a need for any of the ligands coming through.Receptor‐triggered cytoplasmic “interrupt routines”May lead the nucleus to activate new sets of genes,Or otherwise induce a cell, which never reasons why,To twitch, secrete, endocytose, or reproduce, or die.By merely watching labeled ligands bind, we cannot knowDown which of many paths the cells thus tagged are apt to go,But other changes, shortly after binding, may predictWhich of its several options any given cell has picked.Flow cytometric methods are described here which allowMembrane potential to be estimated, to show howPotential changes may occur in seconds after bindingOf ligand to a functional receptor, or for findingNo change when cells don't have the right receptor, or can't seeThe ligand for antagonists of like affinity.With chlorotetracycline fluorescence, one can findRelease of membrane calcium soon after ligands bind;Both this and the potential measurement can help supportDecisions in an instrument about which cells to sort,Though narrowing the distributions which these methods yieldWould greatly help to broaden applications in this field.
Flow cytometry of human reticulocytes based on RNA fluorescence
Authors: Tanke H. J. , Nieuwenhuis I. A. B. , Koper G. J. M. , Slats J. C. M. , Ploem J. S. 
Published: August 2005

AbstractA fluorescent staining procedure based on pyronin Y is described. The technique has been used to stain RNA in human reticulocytes for subsequent flow analysis and sorting. Histograms of fluorescence values of mature red blood cells and reticulocytes obtained by flow cytometry of stained blood samples, contain more information than offered by conventional methods for counting reticulocytes. Analysis of the fluorescence histograms provides new descriptive parameters of the reticulocyte population. The potential importance of this method in experimental and routine hematology is illustrated for a number of clinical cases.
Solid KHT tumor dispersal for flow cytometric cell kinetic analysis
Authors: Pallavicini M. G. , Folstad L. J. , Dunbar C. 
Published: August 2005

AbstractWe used a bacterial neutral protease to disperse KHT solid tumors into single cell suspensions suitable for routine cell kinetic analysis by flow cytometry and for clonogenic cell survival. Neutral protease disaggregation under conditions which would be suitable for routine tumor dispersal was compared with a trypsin/DNase procedure. Cell yield, clonogenic cell survival, DNA distributions of untreated and drug‐perturbed tumors, rates of radioactive precursor incorporation during the cell cycle, and preferential cell cycle phase‐specific cell loss were investigated. Tumors dispersed with neutral protease yielded approximately four times more cells than those dispersed with trypsin/DNase and approximately a 1.5‐fold higher plating efficiency in a semisolid agar system. Quantitative analysis of DNA distributions obtained from untreated and cytosine‐arabinoside‐perturbed tumors produced similar results with both dispersal procedures. The rates of incorporation of tritiated thymidine during the cell cycle were also similar with neutral protease and trypsin/DNase dispersal. Preferential phase‐specific cell loss was not observed with either technique. We find that neutral protease provides good single cell suspensions of the KHT tumor for cell survival measurements and for cell kinetic analysis of drug‐induced perturbations by flow cytometry. In addition, the high cell yields facilitate electronic cell sorting where large numbers of cells are often required.
Monocyte‐induced cell cycle synchronization of a leukemic cell line in vitro
Authors: Eggen Bjørn Magne 
Published: August 2005

AbstractHuman monocytes cultured in vitro exert cytostatic activity against neoplastic cell lines. The cytostatic effect was examinated on the nonadherent human leukemic cell line K‐562. After 24 hours of co‐culture between monocytes and K‐562 cells (in a ratio of 10: 1), the K‐562 cells were removed and their DNA‐synthesis and DNA‐content were examinated by methyl‐3H‐thymidine incorporation and flow cytofluorometry. Cell proliferation curves were obtained.A partial and reversible cell cycle block in the G0G1‐phase was observed. After removal of the target cells from the monoeyte monolayers, the target cells regained their normal proliferation rate during the following 1 to 3 days, with a maximal number of cells in S‐phase at 7 to 9 hours after separation of target cells from the monocytes. The most marked effect was induced by monocytes cultured in vitro for 12 days, and with monocytes stimulated with lymphokine, i.e. supernatants from BCG‐exposed lymphocyte cultures.
Flow cytometric measurement of nuclear DNA content variations as a potential in vivo mutagenicity test
Authors: Otto F. J. , Oldiges H. , Göhde W. , Jain V. K. 
Published: August 2005

AbstractMutagen‐induced variations of the cellular DNA content have been studied in mouse bone marrow cells in vivo using high resolution flow cytometric techniques. During the first days after a single injection of the chemical mutagen cyclophosphamide an increased coefficient of variation in the G1 peak of the flow histograms was observed. The magnitude and duration of this effect were dose‐dependent. The reproducibility of the measurements was high, indicating that individual variability between animals and instrumental dispersion is small. The results demonstrate that on the basis of the flow cytometric measurement of cellular DNA content, a short‐term in vivo test for mutagenicity can be established which is much faster than conventional cytogenetic methods.
Calibration of flow cytometry detector systems
Authors: Durand Ralph E. 
Published: August 2005

AbstractA method of determining the relative intensity of the fluorescence signal measured by a fluorescence activated cell sorter is described. The calibration process is a multistep procedure, in which the signal gain due to the amplifier module is first evaluated, followed by determination of the photomultiplier response as a function of tube voltage for each fluorochrome and filter combination of interest. Using these values, a simple mathematical calculation then determines the relative intensity of a fluorescent signal, even for samples differing in intensity by several orders of magnitude.
The look‐up table: A logarithmic converter for cell sorters
Authors: Koper Ger JM , Blanken Rieks 
Published: August 2005

AbstractThe employment of logarithmic amplifiers for flow cytometers is discussed and a logarithmic conversion algorithm is introduced. Two applications of the algorithm are given: the rescaling of a histogram and the use of a cheap programmable read‐only memory circuit. The performance of the algorithm is compared with a logarithmic amplifier.
Ploidy, proliferative activity and estrogen receptor content in human breast cancer
Authors: Raber Martin N. , Barlogie Barthel , Latreille Jean , Bedrossian Carlos , Fritsche Herbert , Blumenschein George 
Published: August 2005

AbstractTumor samples from 80 patients with breast cancer (43 primary, 37 metastatic) were analyzed for ploidy and proliferative activity using DNA flow cytometry. Sixty‐one tumors (40 primary, 21 metastatic) were also analyzed for estrogen receptor content. Eighty‐five percent of all tumors had an abnormal DNA content. The majority of tumors were hyperdiploid (65%). Seventy‐three tumors had a unimodal ploidy distribution, while in seven cases two distinct aneuploid subpopulations were identified. The degree of ploidy abnormality was not related to extent of disease or menopausal status, but was higher (DNA index > 1.5) in poorly differentiated tumors (p = 0.05). ER‐positive tumors were more often diploid (7 of 31) than ER‐negative tumors (3 of 30, p = 0.16). DNA content was constant in biopsies from multiple sites in 5 patients with metastatic disease and in serial biopsies over the course of the disease. High proliferative activity (percent cells in S‐phase) was more often associated with ER‐negative tumors than ER‐positive tumors (p = 0.03). However, in all subgroups analyzed a wide range of values was noted. We conclude that flow cytometric analysis of cellular DNA content provides a rapid means of quantitating ploidy and proliferative activity in human breast cancer. Ploidy abnormalities were common, stable, and usually unimodal. Proliferative activity was inversely related to estrogen receptor content.
Light scatter analysis and sorting of cells activated in mixed leukocyte culture
Authors: MacDonald H. Robson , Zaech Pierre 
Published: August 2005

AbstractCells activated in unidirectional mixed leukocyte cultures (MLC) have been analyzed on the basis of their light scatter characteristics. C57BL/6 spleen cells were cultured with irradiated (2000 rads) DBA/2 spleen cells for 5 days and the resulting suspension of activated cells was passed on a FACS II flow cytometer. Correlated parameter analysis of forward light scatter (FLS) and perpendicular light scatter (PLS) indicated that the MLC consisted of a heterogenous mixture of viable cells, dead cells, and subcellular debris. However, by appropriate gating of the FLS/PLS distribution, viable cells could be identified as a biphasic FLS histogram. Sorting and morphological analyses of these two FLS peaks demonstrated that they corresponded to almost pure populations of small lymphocytes (lower peak) and lymphoblasts (upper peak), respectively. Furthermore, when sorted cells were tested for their ability to lyse antigenically relevant (DBA/2) tumor target cells in a 51Crrelease assay, lymphoblasts were found to exhibit 40‐fold greater cytolytic activity (on a per‐cell basis) than small lymphocytes.