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 127 records · Page 7Linked to original sources
PubMed1994

TOTO and YOYO: new very bright fluorochromes for DNA content analyses by flow cytometry.

Flow cytometric (FCM) studies were performed on nuclei, ethanol-fixed CHO cells, and isolated human GM130 chromosomes stained with two new cyanine dyes, TOTO and YOYO. These fluorochromes, which are dimers of thiazole orange and oxazole yellow, respectively, have high quantum efficiencies and exhibit specificities for both DNA and RNA. Bound to dsDNA in solution, TOTO and YOYO emit at 530 and 510 nm, respectively, when excited at 488 nm and 457 nm, wavelengths available from most lasers employed in FCM. RNase-treated CHO nuclei, stained with either TOTO or YOYO, provided DNA histograms, with low coefficients of variation, that were as good as or better than those obtained with nuclei stained with propidium iodide (PI) or mithramycin (MI). In addition, by comparison on an equimolar basis, nuclei stained with YOYO fluoresced over 1,000 times more intensely than nuclei stained with MI. Fluorescence ratio analyses of nuclei stained with both YOYO and Hoechst 33258 showed that the ratio of YOYO to Hoechst fluorescence remained relatively constant for G1 and S phase cells, but decreased significantly for cells in G2/M. These results indicate that the cyanine dyes may be useful in examining specific changes in chromatin structure during G2/M phases of the cell cycle. Ethanol-fixed CHO cells stained with TOTO or YOYO did not yield reproducible DNA histograms of good quality, presumably because of the poor accessibility of DNA to these large fluorochromes. However, bivariate analyses of human GM130 chromosomes stained with TOTO or YOYO alone and excited sequentially with uv and visible wave-lengths showed resolution of many individual chromosome peaks similar to results obtained for chromosomes stained with HO and chromomycin A3. Collectively, these studies show potential advantages for the use of these new cyanine dyes in FCM studies that require the sensitive detection of DNA.

Animals↗
PubMed1995

DNA analysis of in situ ductal carcinoma of the breast via flow cytometry.

Flow cytometric (FCM) DNA analysis of 41 clinical cases of ductal carcinoma in situ (DCIS) of the breast was performed on fine-needle aspirates of unfixed, frozen tissue. Based on analysis of a single tissue sample, abnormal DNA content was found in 35 (85%) of the cases, and 15 (37%) disclosed heterogeneity. If five or more samples were analyzed, then heterogeneity was found in eight of ten cases. No conclusive correlation could be found between DNA index (DI) and histopathology. Our results on DCIS demonstrate a very high concordance with invasive breast cancer with respect to the frequency of DNA nondiploid cases, distribution of DI, occurrence of multiple clones, and S-phase fraction. This indicates that major genetic alterations and DNA heterogeneity are early events in carcinogenesis that are already established at the preinvasive stage.

Breast Neoplasms↗
PubMed1984

A comparison of hepatocyte size distribution in untreated and phenobarbital-treated rats as assessed by flow cytometry.

Flow cytometric analysis of narrow forward angle light scatter was used to examine the effect of phenobarbital treatment on hepatocyte size. Light scatter analysis of freshly isolated hepatocytes and of hepatocytes separated by means of centrifugal elutriation into five subpopulations (fractions 1-5) was performed on both untreated and phenobarbital-treated rats. The frequency distribution histogram of forward scatter intensity produced by freshly isolated hepatocytes from untreated rats was used as the baseline. This histogram was arbitrarily divided into four regions; referred to as region 1 (small cells) to region 4 (large cells). Subsequent analysis of the light scatter histograms derived from elutriated fractions of both untreated and phenobarbital-treated animals was performed using these baseline regions. Analysis showed that small cells were enriched in elutriated fraction 1, and large cells in elutriated fraction 5. Phenobarbital treatment was associated with a uniform shift to a higher intensity light scatter (relative increase in cell size) within each of the four selected regions. Our findings suggest that phenobarbital does not have a selective hypertrophic effect on these subpopulations of rat hepatocytes.

Animals↗
PubMed2005

Agonists-induced platelet activation varies considerably in healthy male individuals: studies by flow cytometry.

Flow cytometric evaluation of platelet function extends our understanding of platelets' role in various clinical conditions associated with either bleeding disorders, thrombosis, or monitoring of antiplatelet therapy. The use of suboptimal concentrations of various agonists may allow assessing the "activatability" of platelets. We determined platelet responsiveness to thrombin-receptor-activating peptide-6, arachidonic acid, adenosine 5c-diphosphate (ADP), epinephrine, collagen, and ristocetin at suboptimal concentrations by determination of P-selectin expression and binding of PAC-1 in 26 healthy male individuals. The response varied considerably from one individual to the next. However, within individuals, responses to all agonists except collagen correlated strongly (p<0.05), suggesting a global variability of platelet responses. Moreover, P-selectin expression and PAC-1 binding were strongly correlated (p<0.05). Interestingly, with epinephrine, PAC-1 positive events outnumbered P-selectin positive events, while this was not seen with the other agonists. Thus, epinephrine may specifically affect the conformational switch mechanism and receptor clustering. Our data indicate that the in vitro response to suboptimal concentrations of agonists varies, but individuals with selective platelet defects may still be identified based on data obtained with the various agonists.

Adenosine Diphosphate↗
PubMed1986

Differential toxicity of Physalia physalis (Portuguese man-o'war) nematocysts separated by flow cytometry.

Flow cytometric separation of Physalia physalis nematocysts resulted in isolation of the two previously reported sizes of organelles measuring 10.6 and 23.5 nm in diameter. The venom of the smaller nematocysts, which are present in greater abundance, was lethal in vitro to chick embryonic cardiocytes at doses of 0.6 microgram protein/culture, whereas 20 micrograms protein prepared from the larger nematocysts was inocuous. SDS gel electrophoresis revealed common proteins of 69,000, 82,000 and 50,000-65,000 mol. wt in the nematocyst contents of both sizes of organelles.

Animals↗
PubMed1990

Primary adenocarcinoma of the bladder: favorable prognostic significance of deoxyribonucleic acid diploidy measured by flow cytometry.

Flow cytometric nuclear deoxyribonucleic acid ploidy analysis was done successfully on 38 specimens of primary bladder adenocarcinoma treated between 1954 and 1985. Of the specimens 10 (26%) were deoxyribonucleic acid diploid, 8 (21%) were tetraploid and 20 (53%) were aneuploid. Distribution of ploidy patterns between the 14 histological low grade and 24 high grade tumors was similar. Of 38 tumors 35 (92%) showed muscle invasion. One tumor arose in a previously exstrophied bladder, 10 were of urachal origin and 27 arose in an anatomically normal bladder. Of the urachal origin tumors 80% were deoxyribonucleic acid aneuploid. At 5 and 10 years after diagnosis 80 and 70%, respectively, of the patients with diploid tumors were free of disease. By contrast, at 5 and 10 years after treatment only 20 and 12%, respectively, of the patients with nondiploid tumors have not had disease progression (p less than 0.001 log-rank test). None of the 6 patients with diploid, high grade, high stage, muscle invasive tumors had subsequent progression. In contrast, 16 of 17 patients (94%) with high grade, high stage, nondiploid tumors had either local or distant tumor recurrence (p less than 0.0005). Nuclear deoxyribonucleic acid ploidy pattern appears to be the most significant prognostic information currently available to stratify expected prognosis for patients with muscle invasive adenocarcinoma of the bladder. This test probably should be a standard tool in the clinical management of patients with this rare bladder malignancy.

Adenocarcinoma↗
PubMed1989

Cytotoxic effects of benzene on mouse germ cells determined by flow cytometry.

Flow cytometric (FCM) DNA content measurements were performed on testicular monocellular suspensions obtained from mice exposed per os to 0, 1, 2, 4, 6, and 7 ml/kg body weight of benzene in order to investigate its cytotoxic action on germ cells. The effects of benzene were measured 7, 14, 21, 28, and 70 d after treatment. Benzene had no effect on testis weight, but FCM analysis showed the relative percentages of some cell subpopulations (tetraploid and haploid cells) to be different from the control pattern, indicating the occurrence of some cytotoxic damage to differentiating spermatogonia. These data demonstrate that spermatogenesis is sensitive to benzene single exposures as evidenced by an altered cell ratio of testicular cell types.

Animals↗
PubMed1991

Evaluation of 2-methoxyacetic acid toxicity on mouse germ cells by flow cytometry.

Flow cytometric (FCM) DNA content measurements were carried out on testicular monocellular suspensions obtained from mice exposed per os to a single dose of 50, 100, 300, 600, and 900 mg/kg body weight (b.w.) of 2-methoxyacetic acid (MAA) in order to investigate its cytotoxic action on germ cells. The effects of MAA were evaluated 2, 7, 14, 28, and 45 d after treatment in terms of altered cell type ratios in FCM fluorescence distribution histograms. Testis weight and histological tissue sections were also analyzed. MAA induced marked changes in the relative percentages of tetraploid and haploid cells, indicating the occurrence of cytotoxic damage on primary spermatocytes. Multiparameter FCM analysis showed that, besides its action on nucleic acid synthesis, MAA can also affect the cellular energy metabolism reflected in an altered mitochondrial mass distribution on round spermatids surviving the MAA treatment. This study demonstrates that rapid and unique FCM procedures can be usefully applied in reproductive toxicology.

Acetates↗
PubMed1999

Posttherapy surveillance of B-cell precursor acute lymphoblastic leukemia. Value of polymerase chain reaction and limitations of flow cytometry.

Flow cytometric immunophenotypic analysis is critical in diagnosis and classification of acute leukemia and has been used after therapy to monitor for minimal residual disease. However, the presence of normal B-cell precursors, hematogones, particularly in the context of treated pediatric B-cell precursor acute lymphoblastic leukemia (BP-ALL), may confound such evaluation. In this study, the value of more specific genotypic markers (polymerase chain reaction evaluation of 2 antigen receptor genes) was assessed to resolve this issue. Flow cytometric analysis of enriched mononuclear cells revealed 1% to 20% precursor B cells (PBCs), based on expression of 1 or more pan-B cell antigens in addition to CD10, CD34, and terminal deoxynucleotidyl transferase in all 14 patients studied. Inasmuch as this mimicked the immunophenotype of the original leukemic clone, PBCs, in isolation, were considered suspicious for minimal residual disease. However, 11 of the 14 posttherapy specimens (79%) revealed no monoclonally rearranged antigen receptor genes, and 7 of these 11 patients had trackable genotypic markers at presentation. Accordingly, by PCR these 7 patients had complete molecular remission, supported by clinical follow up of 16 to 73 months. Among the remaining 4 patients with PCR-negative disease, 3 continue in remission, confirming the interpretation of false-positive flow cytometric analysis. In conclusion, flow cytometric monitoring of posttherapy bone marrow specimens from patients with BP-ALL may be misleading, if considered in isolation, in falsely suggesting the presence of minimal residual disease. Rather, PCR for antigen receptor gene rearrangements is a valuable and specific tool, helpful in differentiating hematogones from minimal residual disease in patients with treated BP-ALL whose bone marrow harbors increased PBCs.

Adolescent↗
PubMed1991

Circadian variation in the distribution of cells throughout the different phases of the cell cycle in the anterior pituitary gland of adult male rats as analysed by flow cytometry.

Flow cytometric analysis of nuclei stained with propidium iodide (PI) has been used to study the distribution of cells throughout the different phases of the cell cycle in the anterior pituitary gland of adult male Sprague-Dawley rats at different times of the day. According to PI fluorescence intensity the relative numbers of cells in S phase (cells with a DNA content between that of somatic cells in interphase (2n) and that of somatic cells after duplication of the DNA prior to cell division (4n] and G2/M phase (4n) were calculated. A significant circadian rhythm was found for cells in both the S phase (P less than 0.05) and the G2/M phase (P less than 0.01). The wave of cells in S phase with a peak at the middle of the light period (14.00 h) precedes by about 6 h the wave of cells in G2/M phase (peak at 20.00 h). Most of the DNA-replicating cells were found during the early S phase at 11.00 h, advancing further up to the middle of this phase at 14.00 h. Cells were distributed homogeneously throughout the S phase at 17.00 h. These data strongly suggest that the beginning of the light period triggers a wave of cells to leave G0/G1 into S phase.

Animals↗
PubMedDate not supplied

Clinical applications of flow cytometry.

Flow cytometers allow the rapid, sensitive and quantitative measurement of cells, cell surface markers and cell nuclear components for research and clinical laboratory use. They are producing new insights in many branches of clinical science.

Bromodeoxyuridine↗
PubMed1989

Identification and functional characterization of mononuclear cells by flow cytometry.

Flow cytometric technology has evolved tremendously over the past 5 years. Among the major advancements have been the development of monoclonal antibodies, fluorescent labels, and computer software that makes it possible to perform routine multiparameter analyses. The clinical application of such analyses requires that standards and quality control procedures be established. Areas that need to be specifically addressed include sample preparation, staining, instrument calibration, and sample and data analysis. This study describes the basic elements involved in establishing such procedures and explores the use of multiparameter flow cytometric analysis in the characterization of peripheral blood mononuclear cells. Two-color, flow cytometric analysis of T, B, and natural killer cells can provide important insights into the biologic features of these cells as well as significant diagnostic information.

Antibodies, Monoclonal↗
PubMed1985

[Evaluation of the malignancy of breast carcinoma using flow cytometry].

Flow cytometric DNA analyses of single cell nuclei were performed on nuclear suspensions prepared from tumors of primary breast carcinomas in 40 patients operated on in our hospital. Fluorescence intensities of propidium-iodide stained cell nuclei were analyzed in a SHOWA DENKO SC-20 cell sorter. The DNA index and the percentage of S-phase cells and DNA aneuploidy were calculated from each DNA histogram. There was a tendency for more advanced nodal tumor involvement to have a higher DNA index, increasing DNA aneuploidy proportions and significantly larger percent of S-phase cells.

Adenocarcinoma, Mucinous↗
PubMed1993

[Pheochromocytoma nuclear pattern analysis by flow cytometry].

Flow cytometric nuclear DNA analyses were performed on paraffin-embedded tissue samples taken from 39 patients with pheochromocytoma treated between 1981 and 1992. The Hedley technique was used for measurement of nuclear DNA contents. Only 30 cases out of the 39 tumors were available for the determination of DNA ploidy analyses. Ten cases (33.3%) showed a diploidy pattern, 8-cases (27%) showed an aneuploidy pattern and 12 cases (40%) revealed a tetraploidy pattern. Four cases of malignant pheochromocytoma with regional or distal metastasis had been noted during a mean follow-up period of 4.75 years. All these four cases showed tetraploidy nuclear pattern with vascular invasion on pathological examination, which was statistically significant (p < 0.001) in differentiation between benign and malignant pheochromocytoma. About one third of patients with tetraploidy appeared to have malignant tendencies and this was statistically significant (p < 0.05). None of the patients with either diploidy or aneuploidy pattern had disease progression. The location of the tumor (adrenal vs. extra-adrenal) and 24 hours urine total vanillylmandelic acid (VMA) amounts were not significantly different from the diploid, aneuploid or tetraploid groups. These results suggested that nuclear DNA ploidy pattern is an important independent, and useful prognostic factor for patients with pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed2001

Unique analytical capabilities of laser scanning cytometry (LSC) that complement flow cytometry.

Flow cytometry has become an indispensable instrumentation in many disciplines of biology and medicine. There are some limitations of flow cytometry, inherent to the fact that the cells are measured in flow, which limit its usefulness in some applications. The microscope-based laser scanning cytometer (LSC) has many features similar to flow cytometry but few restrictions of the latter and therefore it is useful in many new applications. This review briefly outlines the applications that are unique to LSC, particularly related to its morphometric capabilities and the possibility of cell relocation. Potential future applications of LSC are also discussed.

Animals↗
PubMed1979

Visualization of multidimensional spectra in flow cytometry.

Flow data from a cell sorter have been processed by hardwired circuits which include amplification, discrimination, coincidence requirements, peak sensing and holding, A-D conversion, and a computerized pulse height analysis with storage of the spectra obtained. Two dimensional spectra can be stored directly in memory, on tape and disk. Three and four parametric cellular events can be recorded on line during the flow measurement in a sequential mode on tape for subsequent recall. Simple processing of these data can be performed for displaying of two dimensional projections from these multidimensional spaces based on threshold conditions for the remaining parameters. Interfaced transmission of the stored data to a large scale computer enables more sophisticated data analysis. Data reduction by means of a multidimensional probability analysis has been carried out in order to transfer the spectra to a computerized picture system for display. This system creates perspective two-dimensional images from a three-dimensional data space. Frequency can be converted into grey levels. Hard copy in color (color as the third dimension and color intensity as frequency) simplifies the visualization of multiparametric flow data sets.

Animals↗
PubMed1977

Cell cycle-related changes in nuclear chromatin of stimulated lymphocytes as measured by flow cytometry.

Flow cytometric techniques have been developed to assay lymphocyte stimulation as reflected by the increase in the cell transcriptional activity and cell progression through the cell cycle. The metachromatic fluorescent dye, acridine orange, is used to (a) stain DNA and RNA differentially in individual cells, and (b) stain nuclear chromatin after removal of cellular RNA BY RNase and cell pretreatment at acidic pH. Stimulated cells with diploid DNA content (G1) have an increased content of stainable RNA that makes it possible to distinguish them from nonstimulated (G0) cells. G0 cells can also be distinguished from G1 cells based on differences in stainability of their nuclear chromatin after treatment with acid. Mitotic indices can be scored automatically, inasmuch as the metaphase chromatin stains differently than does chromatin in the interphase cells. Altogether, the numbers of cells in the G0, G1, S, G2, and M phases may be obtained rapidly and with great accuracy. The cell transciptional activity can be correlated with changes in nuclear chromatin (e.g., during the transition from G0 to G1). The two independent techniques may also prove to be useful in recognizing and quantitating noncycling cells in other cell systems. The possible mechanisms responsible for differential stainability of nuclear chromatin in cells at different phases of the cell cycle are discussed.

Cell Cycle↗