bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of artificial neural networks to chromosome classification
Authors: Errington Phil A. , Graham Jim 
Published: August 2005

AbstractThis work presents an approach to the automatic classification of metaphase chromosomes using a multilayer perceptron neural network. Representation of the banding patterns by intuitively defined features is avoided. The inputs to the network are the chromosome size and centromeric index and a coarsely quantized representation of the chromosome banding profile. We demonstrate that following a fairly mechanical training procedure, the classification performance of the network compares favourably with a well‐developed parametric classifier. The sensitivity of the network performance to variation in network parameters is investigated, and we show that a gain in efficiency is obtainable by an appropriate decomposition of the network. We discuss the flexibility of the classifier developed, its potential for enhancement, and how it may be adapted to suit the needs of current trends in karyotyping. © 1993 Wiley‐Liss, Inc.
Pure populations of Dictyostelium discoideum prespore and prestalk cells obtained by flow cytometry have different redevelopment characteristics at their cell surfaces
Authors: Browne Lois H. , Williams Keith L. 
Published: August 2005

AbstractThe multicellular slug stage of Dictyostelium discoideum consists of two major differentiated cell types: prespore and prestalk cells, which become, respectively, the spores and the stalk of the fruiting body. It is known that these cells, although expressing cell‐type‐specific proteins, remain totipotent, and experimental disruption of slugs results in redifferentiation taking place. We looked at what happens to cell‐type‐specific surface molecules when a cell changes from one type to another. Using monoclonal antibodies and flow cytometry we were able for the first time to obtain pure populations of single cells of each cell type. These were analysed during redevelopment. The initial hypothesis was that a proportion of each cell type would redifferentiate to reestablish the original proportions. However, it was found that the two cell types responded quite differently. Whereas almost all prestalk cells retained their prestalk surface antigen, in contrast, all prespore cells redifferentiated. During this process redifferentiating prespore cells simultaneously expressed surface determinants of both cell types, an event not seen in normal development. © 1993 Wiley‐Liss, Inc.
Double‐staining artefact observed in certain individuals during dual‐colour immunophenotyping of lymphocytes by flow cytometry
Authors: Ekong Theresa , Gompels Mark , Clark Colin , Parkin Jackie , Pinching Anthony 
Published: August 2005

AbstractAn unusual double‐staining artefact has been repeatedly observed in certain individuals (both HIV‐positive and healthy laboratory controls) during 2‐colour immunophenotyping of lymphocytes by flow cytometry after red cell lysis. This artefact can falsely suggest co‐expression of CD4 and CD8, as well as some of the other monoclonal antibody pairs commonly used in the typing of lymphocytes. It is caused by a serum factor associated with the ammonium‐sulphate‐precipitated and gamma‐globulin fractions. It appears to be fairly common in the population (being found in 6 out of 105 of our healthy laboratory controls and in 42 out of 247 of our HIV‐1 seropositive subjects); it may be genetically determined, but may be acquired in some. It is a potential source of error in lymphocyte immunophenotyping, which can be avoided by simple adjustments to the recommended techniques. © 1993 Wiley‐Liss, Inc.
Evaluation of flow cytometry for multidrug resistance detection in low resistance K562 cells using daunorubicin and monoclonal antibodies
Authors: Van Acker Koen L. , Van Hove Luc M. , Boogaerts Marc A. 
Published: August 2005

AbstractWe compared the effectiveness of two flow cytometric methods for the detection of the multidrug resistance (MDR) phenotype. The sensitivity of both methods depended on the ability to discriminate low resistance cells from sensitive ones. Therefore, K562 cells with decreasing vinblastine (VLB) resistance levels were examined, the lowest resistance level being nonmeasurable with a colorimetric MTT assay. The fluorescent drug daunorubicin (DNR) was measured in combination with two modulators of MDR, cyclosporin‐A (CsA) and verapamil (Vp) in a functional flow cytometric assay. When compared to sensitive cells, DNR uptake levels at steady state were reduced in all resistant cell lines, except for the lowest resistant cell line. The effect of modulator, CsA, on DNR uptake was seen in all resistant sublines, compared to sensitive cells, except for the lowest resistant cells. In another assay, the P‐glycoprotein (Pgp) expression was analysed with monoclonal antibodies, MRK16 and C219. MRK16 was found to be the most sensitive antibody to screen for MDR + cells, since we could show Pgp hyperexpression in all resistant cells. C219 reactivity became evident in cells possessing resistance factors higher than 5. These results indicate that both the functional assay and the Pgp assay are sensitive to be used for screening of MDR + cells. © 1993 Wiley‐Liss, Inc.
Concurrent analysis of intracellular glutathione content and gap junctional intercellular communication
Authors: Barhoumi Rola , Bowen Jeffery A. , Stein Lisa S. , Echols Jana , Burghardt Robert C. 
Published: August 2005

AbstractThe potential for performing dual analysis of intracellular glutathione levels and assessment of gap junctional intercellular communication with thiol‐specific fluorescent probes in anchored cells was evaluated. Gap junction‐mediated diffusion of monochlorobimane and 5‐chloromethylfluorescein diacetate following intracellular loading and conjugation with glutathione was compared with 5‐carboxyfluorescein diacetate (which is routinely used in laser cytometry to monitor intercellular communication) by means of fluorescence recovery after photobleaching using a variety of communication‐competent and communication‐incompetent cells. The rate of diffusion of fluorescence among communication‐competent cells was inversely proportional to the size of the fluorescent probe employed. The thiol‐specific probes were also employed to monitor depletion and synthesis of glutathione following treatments to inhibit glutathione synthesis or consume glutathione by adduct formation. Analysis of gap junctional intercellular communication following glutathione depletion revealed a direct correlation between glutathione levels and intercellular communication. These studies support the utility of the thiol‐specific probes to monitor the respective role of cellular glutathione and intercellular communication in the mechanisms of cellular injury. © 1993 Wiley‐Liss, Inc.
Nucleated cells response to protein electroinsertion
Authors: Mouneimne Youssef , Brown Wendy C. , Nicolau Claude , Tosi Pierre‐François 
Published: August 2005

AbstractApplication of an electrical pulse field at a strength slightly below the value required for electroporation to a suspension of red blood cells in the presence of membrane xenoproteins leads to the insertion of those proteins in the erythrocyte plasma membrane. This observation is extended to nucleated cells. In the presence of glycophorin A, application of such pulses leads to the insertion of 104–105 molecules of glycophorin A per cell in CEM‐CM3, Hela S3, and bovine CD8+ T cells. Electroinserted glycophorin A is detected by flow cytometry using antiglycophorin monoclonal antibodies. The survival of the cells subjected to electroinsertion was 55% for CEM‐CM3 cells, 69% for Hela S3 cells, and 65% for CD8+ T cells. Cells cultured after electroinsertion lost the electroinserted glycophorin A, with two different rates, by a temperature and cell type‐eependent mechanism. During the first 2 h after electroinsertion, the CD8+ T cells lost 12.5% of the inserted glycophorin A per h, the CEM‐CM3 cells lost 7.7% per h, whereas the Hela S3 cells lost only 0.8% of the inserted protein per h. After 2 h, the rate increased substantially, to 41.7% per h for the CD8+ T cells, 13.5% for the CEM‐MM3 cells, and 8.9% for the Hela S3 cells. Cytochalasin D efficiently inhibited the disappearance of electroinserted glycophorin A during the first 2 h after electroinsertion only. © 1993 Wiley‐Liss, Inc.
Characterization of the differentiation of human colorectal cancer cell lines by means of Voronoi diagrams
Authors: Darro Francis , Kruczynski Anna , Etievant Chantal , Martinez Jean , Pasteels Jean‐Lambert , Kiss Robert 
Published: August 2005

AbstractThis paper describes differentiation in terms of population dynamics through the medium of Voronoi paving which enables (via digital cell image analysis) the structure of human LOVO and HCT‐15 colorectal neoplastic cell colonies growing on histological slides to be characterized. Two other tests were also used, i.e., the colorimetric MTT assay that enables the cell growth level to be determined, and a test allowing the assessment of the proliferation index, i.e., the percentage of cells in the S phase of the cell cycle. The results show that these colorectal neoplastic cells exhibited a comparatively high level of organisation in terms of the topographical distribution of nuclei within the clones when the cells were cultivated in media containing even small amounts of fetal calf serum. On the other hand, certain chemically defined media completely overturned this “pseudo‐tissular” architecture. Furthermore, the colorectal cells growing in media including fetal calf serum exhibited relatively large and dense clones, undergoing an increase in the density of these clones when hormones were added to the culture medium and, concomitantly, a decrease in their proliferation. In contrast, the cells growing in chemically defined media generally exhibited smaller clones whose cell proliferation was paradoxically greater than that of the cells referred to above. This seems to bring out the importance of the part played by the cell loss factor in this cell population dynamic. © 1993 Wiley‐Liss, Inc.
Preferential loss of abnormal prostate carcinoma cells by collagenase treatment
Authors: König Josée J. , van Dongen Jan Willem , Schröder Fritz H. 
Published: August 2005

AbstractEffects of two different methods of tumor disaggregation on flow cytometric ploidy distribution and intact cell yield were investigated. Either mechanical disaggregation or collagenase digestion was applied to 35 prostate tumor specimens. Seven collagenase‐treated samples failed to yield any intact cells, whereas with mechanical disaggregation in all cases a sufficient number of intact cells were obtained. No differences in the FCM ploidy distribution of tumors with a DNA diploid stemline were observed comparing both techniques. In DNA aneuploid tumors, however, collagenase treatment had an adverse effect on the abnormal cell populations. In 14/17 of such tumors, the abnormal cell populations were significantly reduced; in eight of these the percentage of DNA aneuploid cells declined even below the minimum percentage (10%) that was defined for DNA aneuploidy. Since collagenase is a widely used enzyme for tissue disaggregation, especially in tumor cytogenetics, the presented data will have consequences for the interpretation of results obtained by methods involving the use of this enzyme. © 1993 Wiley‐Liss, Inc.
Rapid flow cytometric antibiotic susceptibility assay for Staphylococcus aureus
Authors: Ordóñez José V. , Wehman Natalie M. 
Published: August 2005

AbstractConventional techniques for antibiotic susceptibility testing usually require 24 h or more to produce accurate results. This long waiting period to demonstrate antibiotic action is necessary because such tests rely on growth (or the lack of it), when the microorganisms are incubated in the presence of the antibiotic. In an effort to improve antibiotic susceptibility testing, we developed a flow cytometric technique for Staphylococcus aureus in which antibiotic action is determined by monitoring drug‐gnduced membrane potential changes, using the potential‐sensitive dye 3,3′‐dipentyloxacarbocyanine iodide. Three ATCC reference strains of S. aureus and 13 unknown strains of the same microorganism were tested for susceptibility to penicillin G and oxacillin. Our results indicate that susceptibility of S. aureus to these antibiotics can be measured reliably at 90 min after addition of the antibiotic, and the results are comparable to those obtained with conventional susceptibility tests. © 1993 Wiley‐Liss, Inc.
Beam‐shaping optics for a slit‐scan flow cytometer
Authors: Noguchi Yoshio , Kashima Shingo , Aikata Takashi 
Published: August 2005

AbstractTwo sets of beam‐shaping optical systems for slit‐scan flow cytometry were made for 360 nm and 488 nm wavelength argon‐ion lasers. A thin, ribbonlike laser beam was formed by compressing the zero‐order component of Fraunhofer diffraction patterns caused by a slit vertically long and horizontally narrow by means of an objective with a numerical aperture of 0.5. The objectives were designed to include a jet stream that performed as a cylindrical lens. The characteristic values of the optical systems and lens alignments of the systems are described in this work. The beam size at focus was 0.95 μm in thinness and 85.0 μm in width on design values. The actual beam thinness for the UV laser was estimated to be 1.3 μm, based on shapes of pulses generated when fluorescence microspheres of diameter 1.0 μm passed across the beam. The usefulness of the optical systems was also proved by its ability to measure HeLa chromosomes. © 1993 Wiley‐Liss, Inc.
Flow cytometric assay of pinocytosis: Correlation with membrane ruffling and metastatic potential in the dunning R‐3327 rat prostatic adenocarcinoma model
Authors: Mohler James L. , Sharief Yousuf 
Published: August 2005

AbstractMembrane ruffling has been associated with neoplastic transformation, Harvey ras expression, and metastatic capability. In the Dunning R‐3327 rat prostatic adenocarcinoma model, membrane ruffling graded visually upon live cultured cells filmed by time‐lapse video‐microscopy has distinguished sublines of high and low metastatic potential. Fluid‐phase pinocytosis is a constitutive, noninducible internalization of medium by cell membrane. Fluid phase pinocytosis may be measured flow cytometrically by cellular uptake of fluorescein‐labelled medium constituents.The optimum conditions for a flow cytometric assay of pinocytosis were determined using AT‐2 subline that has an intermediate degree of membrane ruffling. The optimum dextran concentration was selected from the midpoint of the linear portion of the dose‐eesponse (0.01–10.00 mg/ml) curve, whereas the optimum incubation time was determined from a time course (1—405 min.) curve study. Cultured cells from 6 Dunning sublines incubated with 1.0 mg/ml of fluorescein‐labelled dextran for 90 min were washed, fixed, and the fluorescence of 10,000 cells studied by flow cytometry. For each subline, dextran fluorescence was measured in four independent experiments. Pinocytosis failed to distinguish sublines of high (AT‐3 63.5 ± standard error 4.1 mean channel number, MAT‐LyLu 63.2 ± 6.3, MAT‐tu 64.3 ± 5.6) and low (G 33.5 ± 1.2, AT‐1 63.5 ± 4.1, AT‐2 58.4 ± 3.6) (rank p = 0.38) metastatic potential but correlated strongly with visually graded membrane ruffling (r = 0.95, p = 0.003). Pinocytosis assayed by flow cytometry reflects membrane ruffling observed visually and thus flow cytometric assays may facilitate study of membrane activity. © 1993 Wiley‐Liss, Inc.
Development of a shape vector that identifies critical forms assumed by human polymorphonuclear neutrophils during chemotaxis
Authors: Hartman Raymond S. , Lau Kin , Chou William , Coates Thomas D. 
Published: August 2005

AbstractHuman polymorphonuclear neutrophils undergo characteristic shape changes that are critical to their ability to move and ingest their targets. We present here the construction of a simple shape vector, calculated from the coordinates of the cell perimeter, that can identify critical forms that a neutrophil assumes during the course of ameboid movement. The vector can be used to find neutrophils of a specific shape from the image analyzer data produced during a typical neutrophil tracking experiment. © 1993 Wiley‐Liss, Inc.
Quantitation of adhesion molecules and other function‐associated antigens on human peripheral blood leucocytes
Authors: Macey M. G. , McCarthy D. A. 
Published: August 2005

AbstractQuantitating satisfactorily the expression of adhesion molecules and other functional antigens on the surface of human peripheral blood granulocytes by flow cytometry is difficult. Artefactual (in vitro) changes, which occur in the expression of these molecules during conventional cell preparation and labelling procedures, led to the development of a leucocyte preparation technique that prevents upregulation of the leucocyte integrins and other antigens. The technique, as originally evaluated, involves fixing freshly drawn blood with formaldehyde (final concentration 0.2%) for 4 min at 37°C before adding ammonium chloride to lyse the erythrocytes; procedures which are inconvenient when blood samples are taken in wards or clinics that are some distance from a laboratory. We therefore investigated (i) whether blood could be kept with commonly used anticoagulants for up to 1 h before fixation, and (ii) whether unantico agulated blood could be kept with formaldehyde for a similar period before processing was continued. The results showed that when quantitating those granulocyte surface antigens which can be rapidly upregulated: (i) that it is preferable to mix freshly drawn unanticoagulated blood directly with formaldehyde; (ii) that if blood must be collected into anticoagulants, it should be kept for only the briefest possible time before processing; and (iii) that the time for which cells are exposed to 0.2% formaldehyde must be carefully controlled and limited to 4 min. A corollary of the results with anticoagulants is that it is probably impossible to isolate live granulocytes by currently available procedures without artefactually altering the expression of these antigens in vitro. © 1993 Wiley‐Liss, Inc.
Differences in relative DNA content between human peripheral blood and bone marrow subpopulations–consequences for DNA index calculations
Authors: Jensen Inger Marie , Ellegaard Jørgen , Hokland Peter 
Published: August 2005

AbstractBy sequentially staining for leukocyte differentiation antigens with monoclonal antibodies and for stainable DNA content with propidium iodide, we have evaluated the DNA ratios of normal peripheral blood and bone marrow subpopulations. In 19 peripheral blood samples the relative DNA content of the monocytes was higher than that of other subpopulations, with highly significant differences between the DNA ratios of the CD14+ monocytes, on the one hand, unlabeled controls, CD3+ T‐lymphocytes, and CD20+ B‐lymphocytes, on the other. In bone marrows from 16 healthy volunteers, the relative DNA content of the myelomonocytic subpopulations was higher than that of the T‐lymphocytes with significant differences between the CD3+ lymphocytes, on the one hand, and the CD14+ monocytes, the CD13+ and CD33+ immature myeloid, the NAT9+ mature myeloid, and the AS‐E1+ nucleated erythroid subpopulation, on the other. Since a mixture of peripheral blood mononuclear cells or T lymphocytes from healthy volunteers is often used as an external standard for DNA ploidy determinations, these data suggest that such a procedure could result in an overestimation of the DNA indices of most of the bone marrow subpopulations. Instead, we suggest the use of the DNA ratio of the CD14+ subpopulation from peripheral blood as standards for ploidy determinations for the myeloid bone marrow subpopulations. © 1993 Wiley‐Liss, Inc.
Flow and image cytometry for DNA analysis in bladder washings: Improved concordance by using internal reference for flow
Authors: Chabanas Agnègs , Rambeaud Jean‐Jacques , Seigneurin Daniel , Fradet Yves , Lawrence Jean‐Jacques , Faure Gilbert 
Published: August 2005

AbstractUsing flow or image cytometry, we compared the DNA distribution of cells from bladder washings from 52 patients with bladder cancer. For image cytometry, urothelial nuclei (recognized visually) were analyzed for DNA content using polymorphonuclear nuclei as internal diploid reference. For flow cytometry, two methods can be used: either all cells can be analyzed, as commonly performed, or urothelial cells can be analyzed alone, after specific derection. In this flow cytometry study, cells were doubly stained for panurothelial antigen T16 and for DNA. All the cells were first analyzed using peripheral lymphocytes as an external reference; 79% of the results were similar with results obtained from image analysis. For discordant results, flow‐cytometric data were reprocessed to identify immunologically stained urothelial cells; one additional case became concordant with image cytometry when only urothelial cells were analyzed, with lymphocytes as diploid reference; a better concordance (94%) was found when the nonurothelial cells of the samples served as a diploid reference instead of peripheral lymphocytes. This suggests that we achieved an improvement of the flow‐cytometric evaluations for ploidy assessement, and we conclude that, on these conditions, flow or image analysis can be considered as equivalent methods for DNA content studies of tumors. © 1993 Wiley‐Liss, Inc.
Subtraction of autofluorescent dead cells from the lymphocyte flow cytometric binding assay
Authors: Zamai L. , Bareggi R. , Santavenere E. , Vitale M. 
Published: August 2005

AbstractFlow cytometry allows the quantitative analysis of lymphocyte–target cell conjugates and the identification of the lymphocyte subset involved in the binding phenomenon. We recently described a methodology to identify the effector cells bound to K562 targets based on target cell autofluorescence coupled with lymphocyte staining by means of fluorescent monoclonal antibodies. Here we describe an implementation of the methodology that allows the subtraction of spontaneously dead targets to which lymphocytes may or may not adhere, thereby preventing the overestimation of the binding phenomenon and limiting its evaluation to living effector‐target conjugates, thus preserving the specificity of the phenomenon. © 1993 Wiley‐Liss, Inc.
Rapid separation of CD4+ and CD19+ lymphocyte populations from human peripheral blood by a magnetic activated cell sorter (MACS)
Authors: Semple John W. , Allen David , Chang Wilda , Castaldi Patrick , Freedman John 
Published: August 2005

AbstractRapid purification of human lymphocyte subpopulations is an essential step in order to elucidate their interactions and/or contributions in various disease states. Cell purification using a Magnetic Activated Cell Sorter (MACS) is a relatively new technology which has been shown to be rapid and yield highly purified populations of cells. This report describes both a simple one‐step positive selection method using the MACS to purify either human CD4+ or CD19+ lymphocytes from PBMC and a sequential separation of both CD4+ and CD19+ cell populations. These methods can separate the cell populations in approximately 4 h with yields >90% and purity of 97 ± 3% for CD4+ T cells and 92 ± 5% for CD19+ B cells. In functional studies, purified CD19+ B cells secreted 13‐ and 24‐fold more IgM and IgG, respectively, than the CD19− cell fraction in 10 day B cell stimulation assays. Purification of the two cell types did not cause any significant activation as shown by proliferation. Both cell types, however, were able to proliferate upon stimulation with interleukin‐2. © 1993 Wiley‐Liss, Inc.