PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “flow cytometry”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1979

Fast imaging in flow: a means of combining flow-cytometry and image analysis.

The morphological identification of cells by flow cytometry is difficult. Usually cell sorting and microscopical analysis have to be used in addition. Morphological analysis is simplified by taking cell pictures from a range of particular interest immediately during flow cytometric analysis. Instruments using the video scanning technique for fluorescence imaging are slow and expensive (8, 10). Morphological information can also be obtained by transmission imaging of cells in flow, which requires shorter exposure times. Therefore a cell volume activated flow imaging device has been developed which operates at flow speeds up to 5 m/sec and which depicts transmission images of selected cells on a 16-mm film by a nsec flashlamp illumination. An electronic unit detects the particles in the optically accessible orifice, performs the pulse height analysis, triggers the flashlamp if particles are in the preselcted range of interest and feeds the film. The instrument is capable of delivering up to 150 pictures per second and works either as a flow microscope in which the cells in the preselected volume range are directly observed, or as a picture system in which the cell pictures are stored on the 16-mm film for documentation or for image analysis.

Cell Count↗
PubMed1979

A template method for decomposing flow cytometry histograms of human chromosomes.

A new method for decomposing flow cytometry histograms of isolated human metaphase chromosomes is described and tested. The method is based on fitting a template, composed of the means of all chromosomes of a normal karyotype to the flow histogram. The utility of the method is demonstrated by application to flow measurements of chromosomes from a normal person and comparing the results with those obtained by conventional cytophotometry. The power of the method for detecting gross chromosomal abnormalities, such as trisomy 21, as well as more subtle variations such as a single translocation, is determined for simulated data.

Chromosome Aberrations↗
PubMed1979

Dynamic assay of enzyme activities in single cells by flow cytometry.

Three enzymes in single cells were assayed dynamically by flow cytometry using four fluorogenic substrates. Acid phosphatase was determined with 7-bromo-3-hydroxy-2-naphtho-o-anisidine (naphthol AS-BI) phosphate and 4-methylumbelliferone (MU) phosphate, neutral esterase with fluorescein diacetate, and lactic dehydrogenase with NAD-sodium lactate. Fluorescence measurements obtained with the flow cytometer were converted into relative specific enzyme activities for single cells with molar fluorescence coefficients determined with a spectrofluorometer. Specific activities obtained from spectrofluorometric data were compared with activities calculated from flow cytometeric data. Flow cytometric assays gave lower specific single cell activities for 4-methylumbelliferone phosphate hydrolysis and for lactic dehydrogenase than did similar assays by standard spectrofluorometry. Product diffusion may be the greatest cause for this discrepancy.

Acid Phosphatase↗
PubMed1979

Flow cytometry: a high-resolution instrument for everyone.

A new flow configuration for flow cytometry has been devised in which a flat, laminar stream of water, containing the stained cells in a narrow sector, is formed on a microscope cover slip by a pressurized jet of water directed onto the glass at low angle. The stream of cells is viewed by means of a fluorescence microscope with incident illumination and a pulse photometer. Coupled to a multichannel pulse height analyzer, the instrument constitutes a stable and easy-to-operate flow cytometer with a resolution equal to or better than a coefficient of variance of 1.4 percent in measurements of cellular DNA.

Animals↗
PubMed1979

A study of acid phosphatase and dipeptidyl aminopeptidase II in monodispersed anterior pituitary cells using flow cytometry and electron microscopy.

A brief historical review of cytoenzymology is presented from the time of introduction into electron microscopy to the present, where the direction for quantification of an enzyme in single cells appears most promising by fluorescent staining. First attempts are reported to quantitate acid phosphatase (AcPase) and dipeptidyl aminopeptidase II (DAP-II) in monodispersed anterior pituitary cells from lactating and postlactating rats by flow cytometry, fluorescent, and electron microscopy. 3-Hydroxy-flavone is introduced as a new fluorescent cytochemical stain for AcPase, useful in flow cytometry but of only limited use in fluorescent microscopy. Histograms for AcPase indicate a single peak of cells staining more intensely in cell preparations from postlactating over lactating animals. Histograms for DAP-II staining indicate two distinct populations of cells present in the lactating and only one in the postlactating rat anterior pituitary gland. The application of dual laser staining indicates that not all cells stain for both enzymes. Electron microscopy shows the subcellular localization of DAP-II to be limited to lytic bodies and in mammotrophic cells to some secretion granules.

Acid Phosphatase↗
PubMed1979

Nonparametric flow cytometry analysis.

A nonparametric statistical test for the analysis of flow cytometry derived histograms is presented. The method involves smoothing and translocation of data, area normalization, channel by channel determination of the mean and S.D., and use of Bayes' theorem for unknown histogram classification. With this statistical method, different sets of histograms from numerous biological systems can be compared.

Cells, Cultured↗
PubMed1979

DNA flow cytometry of isolated keratinized epithelia: a methodological study based on ultrasonic tissue disaggregation.

Ultrasonication of keratinized, stratified, squamous epithelium, which had been separated from underlying tissue by means of acetic acid, resulted in disaggregation of all cellular layers in the epithelium, giving a suspension of single nuclei with mitoses preserved. This suspension was treated with RNAse and ethidium bromide for analysis by flow cytometry. From the resulting DNA histogram the G1, S and G2 + M fractions were estimated using the computer program of Fried (1976). Treatment with dithiothreitol before sonication increased the yield of nuclei in suspension and decreased the amount of debris and clumps, thereby suppressing overestimation of small S fractions. This method of preparation prior to DNA flow cytometry was useful for the study of the hamster cheek pouch epithelium and of normal and pathological human epidermis.

Animals↗
PubMed2026

Multiparametric flow cytometry immune profiling of pulmonary and extra-pulmonary tuberculosis reveals distinct blood-based biomarker signatures.

This study investigated immune cell distributions, cell-specific immune markers, and selected biomarker targets in pulmonary tuberculosis (PTB) and extrapulmonary tuberculosis (EPTB) using multiparametric flow cytometry (MFC). Whole blood was collected from 45 individuals, including healthy controls (HC), EPTB, and PTB patients (n&#x202f;=&#x202f;15/group). Peripheral blood leukocytes were analysed by MFC to characterize CD4+ and CD8+ T cells, natural killer (NK), invariant NKT (iNKT) and NKT cells, classical (CM), intermediate (IM) and non-classical monocytes (NCM), and activated monocytes (AM). Expression of GBP1, CALCOCO2, IFIT3, SNX10, ARG1, PD-1, and PD-L1 was assessed across these immune subsets. Increased frequencies of NK, NKT, and monocytes were observed in PTB and EPTB compared with HC, while CD4+, CD8+, iNKT, and AM were reduced. Monocyte-to-lymphocyte ratios were incrementally elevated in EPTB and PTB compared with HC. Despite variability of expression within groups, median biomarker fold-change expression changes were found between HC, EPTB and PTB groups; (i) (>2.0FC) for ARG1 in CD4, CD8, CM and AM, for CALCOCO2 in AM, GBP1 in CD8 and NCM, PD-1 in CD4, CD8, NK, IM and AM, PD-L1 in CD4, CD8, iNKT and NKT, NK, IM and AM and SNX10 in CD4, CD8, NCM, IM and AM (ii) (<2.0FC) in TB vs HC for CALCOCO2 in iNKT and NKT, IFIT3 in NCM, PD-1 in NK and NCM, PD-L1 in NCM, IM and AM and SNX10 in AM. Statistical significance was achieved for ARG1 (P&#x202f;=&#x202f;0.017) in CD4 cells. Our findings highlight distinct immune cell and biomarker signatures in PTB and EPTB.

Humans↗
PubMed1979

Multi-user system for analysis of data from flow cytometry.

A new program is described for the analysis of DNA histograms from flow cytometry. The fundamental model representing the cell population is similar to one described previously. It assumes the population is grouped into compartments, each consisting of cells having approximately the same DNA content. After staining the cells with an appropriate fluorochrome, the fluorescence distribution of cells within each compartment is assumed to be Gaussian. In the present algorithm, the parameters of the model can either be computed directly by the program from the data, or can be specified as input by the user. When synchronous cell populations lacking distinct G1 and G2/M phases are analyzed, the parameter values must first be obtained using an appropriate control. Percentages of cells in the various compartments are computed using a gradient search method described by Bevington.

Computers↗
PubMed1979

Fluorescent DNA probes for flow cytometry. Considerations and prospects.

Techniques employing base specific deoxyribonucleic acid (DNA)-binding fluorochromes and flow cytometry (FCM) are potentially useful for obtaining information of the compositional features of chromatin or chromosomes of mammalian cells. Fluorescent compounds which form complexes preferentially at the A-T rich regions (i.e., DNA-reactive Hoechst dyes) or the G-C rich regions (i.e., mithramycin, chromomycin, olivomycin) in DNA are available and compatible with current FCM technology as are other compounds (i.e., ethidium bromide, propidium iodide) which show little or no base specificity and bind by intercalation in the double stranded regions of helical DNA. Energy transfer between appropriate DNA-bound dyes is a reflection of the quantity and proximity of regions containing the respective base pair segments. Since extrinsic fluorescent probes provide only a measure of available binding sites or regions unobstructed by chromatin-associated or chromosomal-associated proteins, interpretations of fluorescence measurements need to be substantiated by adequate control measures.

Animals↗
PubMed1979

Cell-cycle distribution of urothelial tumour cells as measured by flow cytometry.

The fraction of cells in S + G2 + mitosis from 54 urothelial tumours was calculated by flow cytometry after acridine orange (AO) staining of cells obtained by bladder irrigation or biopsy. Fluorescence signals emitted by the AO-stained DNA and RNA of each cell were separated optically and measured for 5,000 cells per specimen. The patients were classified by the histology of their tumours and clinical data into 5 diagnostic categories: NED (no evidence of disease, but history of bladder tumour), 3; papilloma, 8; non-invasive papillary carcinoma, 8; carcinoma in situ, 17 and invasive carcinoma, 18. The fraction of cells with DNA values in S + G2 + M of the cell cycle varied between 7 and 57% of the total, with a wide range within each diagnostic category, but no statistically significant differences between the groups. The proportion of cells in S + G2 + M from an individual tumour was not correlated with histologic grade or clinical behaviour. The possibility that some tumour cells with DNA values above G1 level are quiescent cells arrested at S or G2 is discussed.

Cell Count↗
PubMed1979

Flow cytometry of human gynecologic specimens using log chromomycin A3 fluorescence and log 90 degrees light scatter.

Flow cytometry and electronic cell sorting are being investigated to screen gynecologic specimens for cervical neoplasia. Cellular DNA content is quantitated by Chromomycin A3 fluorescence and cell size is quantitated by 90 degrees light scatter; the logarithms of the measured intensities are used to produce a two parameter histogram. To determine the cell types responsible for signals in various histogram regions, systematic electronic cell sorting is performed. The sorted fractions are sedimented into microscope slides and stained by the Papanicolaou technique. The cells in each fraction are identified by conventional cytomorphologic criteria. Morphologic analysis of sorted cells reveals histogram regions corresponding to specific cell types. One very important region contains the highest concentration of signals from abnormal cells and is therefore the best region to analyze for specimen abnormality. However, because a significant number of signals in this region are from normal cells, specimens cannot be diagnosed by their analysis. Another important histogram region is composed primarily of signals from endocervical columnar and metaplastic cells. The presence of such cells is a good criterion for specimen adequacy, therefore analysis of signals in this region is essential to assess specimen adequacy for automatic screening.

Cervix Uteri↗
PubMed1979

Lymph node reactivity to experimental bladder tumor in preimmunized animals as measured by two parameter flow cytometry.

Lymph node lymphocyte reaction to an explanted, transplantable mouse bladder tumor (MBT-2) was investigated by flow cytometry in animals previously immunized with irradiated tumor cells. Nodal lymphocytes in representative samples from four different lymph node sites were differentially stained for DNA and RNA with the fluorescent dye acridine orange; cell proliferation and the increase in RNA content were measured. Immunization abrogated tumor growth; one immunization reduced tumor take to 25 per cent of the animals, and two immunizations to 14 per cent. Lymphocyte reactivity to the tumor was reflected both by an increase of DNA synthesizing cells and by diploid cells with high RNA. The latter response was more pronounced and thus the more sensitive parameter for measuring immunologic lymph node reactivity. The juxtatumoral node displayed the most pronounced reactivity, but all node sites showed some degree of reaction.

Animals↗
PubMed1979

Measurement and purification of human chromosomes by flow cytometry and sorting.

The 24 human chromosome types of normal diploid fibroblast cell strain were classified into 15 groups by high-resolution flow cytometry on the basis of 33258 Hoechst fluorescence. Chromosomes associated with each group were flow sorted onto microscope slides and identified by quinacrine banding analysis. DNA cytophotometry of metaphase chromosomes from the same cell strain supported and extended this identification. Four of the groups purified were due to chromosomes of a single type--namely, chromosomes 5, 6, 13, and 17. Eight additional groups were also separated and found to contain the following chromosomes: 1 and 2; 3 and 4; 7, 8, and X; 9--12; 14 and 15; 16 and 18; 20 and Y; and 19, 21, and 22. The average purity for the 12 sorted fractions was 78%.

Cell Line↗
PubMed1978

Characterization of bladder tumours by flow cytometry on bladder washings.

The DNA content of individual nuclei in bladder washings was estimated by means of flow cytometry. A method of preparation using a detergent to produce single nuclei was used. By means of a differential count the DNA distribution was corrected for the content of leucocytes. The DNA histograms were divided into a 2c fraction containing nuclei with less than 3c DNA, a 4c fraction with 3c--6c DNA and an 8c fraction with more than 6c DNA. Three groups of patients were investigated: 17 patients with invasive bladder tumours, 38 patients with non-invasive bladder tumours, and 22 patients with normal bladders. The washings from patients with invasive tumours contained significantly larger 4c and 8c fractions than washings from normal bladders. There was a correlation between cell anaplasia and the DNA distribution: grade III bladder tumours had larger 4c and 8c fractions than grade II tumours.

Cell Nucleus↗
PubMed1979

Size measurements on isolated rat heart cells using Coulter analysis and light scatter flow cytometry.

Isolated ventricular muscle cells from the adult rat heart have been examined by both Coulter analysis and light scatter flow cytometry. The dispersed cell preparations contain two main cell types: viable, rod-shaped cells and damaged, round cells. Coulter analytical techniques provided statistical data on cell volume for both cell types. The contribution of each population to the Coulter pulse height distributions were separated by a subtraction method using data obtained from digitonin-treated preparations that contain only round cells. A shape factor for cells aligned with the flow direction was computed from light microscope measurements and the effects of cell orientation within the Coulter aperture were approximately assessed. The estimated volumes for intact myocytes compare favourably with those reported in the literature. No significant size difference was observed between fresh and fixed cells. Narrow angle, forward light scatter measurements were made on individual cells flowing across a focused laser beam. Both scatter pulse height and pulse width (pulse duration) distributions were collected. Values for myocyte length calculated from pulse width information agree well with published data and confirm that the hydrodynamic forces in the flow system produced alignment of the cells with the flow direction. Scatter pulse width distributions reveal two distinct peaks assignable to either rod or round cells. Preliminary electronic gating experiments, using pulse height signals, suggest that signals derived from round cells could be eliminated entirely using a gating regime based on pulse width. This would enable flow cytometric measurements to be made on only the intact myocytes present in heterogeneous preparations.

Animals↗
PubMed1979

Regional lymph node reactivity in explanted bladder cancer of mice as measured by flow cytometry.

The reactivity of lymphocytes in lymph nodes draining the site of a transplantable experimental bladder tumor (MBT2 in C3H/HeJ mice) has been measured in a multiparameter flow cytometry system. Acridine orange was used as a nucleic acid probe. This dye intercalates in helical DNA, emitting green (530 nm) fluorescence upon exposure to blue light; it stacks to single-stranded RNA, emitting red (640 nm) fluorescence. The relative magnitude of the increase of lymphocyte DNA and RNA has been evaluated simultaneously in tumor-draining nodes, in nondraining nodes of the same animal, and in untreated control animals. Stimulation of the regional node lymphocytes could be observed after 20 days but not after 10 days. It was uniformly high at 35 days. The transcriptive response (increased proportion of lymphocytes with high RNA) was more pronounced than the proliferative (increased proportion of lymphocytes with more than diploid DNA). The histological changes in the stimulated nodes resembled closely those described by others in human tumor-draining nodes. The described method has the advantage of being simple, rapid, and able to measure a representative part of the whole-cell population.

Animals↗