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 217 records · Page 12Linked to original sources
PubMed1991

Quantification of mitochondrial proteins in cultured cells by immuno-flow cytometry.

Immuno-flow cytometry was tested as a tool to estimate the cellular concentration of mitochondrial proteins in cultured cells, using cytochrome c oxidase as a model enzyme. Cells labelled with antibodies against cytochrome c oxidase, in which the amount of the enzyme was reduced by various extents, showed a linear relationship between the size of the signal obtained by immuno-flow cytometry and the amount of the enzyme. The determination by immuno-flow cytometry resulted in data comparable to the results obtained by immunoprecipitation and activity measurements. Since immuno-flow cytometry requires only limited numbers of cells, the method could especially be of value for diagnostic purposes. This is illustrated by the results obtained by comparing activity measurements and immuno-flow cytometry in the initial screening of cell lines derived from patients with deficiencies in the activity of cytochrome c oxidase.

Cells, Cultured↗
PubMed2001

Flow cytometry: an improved method for the selection of highly productive gene-amplified CHO cells using flow cytometry.

In previous work, we clarified the relationship between the productivity and stability of gene-amplified cells and the location of the amplified gene. The location of the amplified gene enabled us to classify resistant cells into two types. One type of resistant cell group, in which the amplified genes were observed near the telomeric region, was named the "telomere type." The other type of cell group, in which the amplified genes were observed in other chromosomal regions, was named the "other type." The phenotypes of these two types of cells are very different. In this experiment, using a fluorescein isothiocyanate-labeled methotrexate (F-MTX) reagent with flow cytometry, we were easily able to distinguish between highly productive cells and the other types of cells. The level of fluorescence differed according to the difference in resistance to MTX. Based on this new finding, highly productive gene-amplified cells could be isolated from heterogeneous gene-amplified cell pools more easily than by the method of limiting-dilution assay. The limiting-dilution method requires several months to obtain highly productive gene-amplified cells, while our flow-cytometry-based method of selection requires only a few weeks.

Animals↗
PubMed1996

Seminal fluid antisperm antibodies measured by direct flow cytometry do not correlate with those measured by indirect flow cytometry, the indirect immunobead test, and the indirect mixed antiglobulin reaction.

OBJECTIVE: To compare the direct flow cytometric (FCM) measurement of sperm-bound antibodies with the indirect FCM measurement of unbound antisperm antibodies in seminal plasma of the same ejaculates. To compare the FCM measurements with the indirect mixed antiglobulin reaction (MAR) and the indirect immunobead test (IBT) performed on the same seminal plasmas. SETTING: University hospital-based infertility service. PATIENTS: Eleven infertile men with a positive immunoglobulin (Ig) G direct MAR test and antibody positivity on the direct FCM measurements. Four control patients with a negative IgG-direct MAR test. MAIN OUTCOME MEASURES: The proportion of spermatozoa positive for IgG and IgA antibodies as measured by various tests. RESULTS: The direct and indirect FCM measurements for sperm-bound antibodies from seminal plasma did not correlate with each other. In general, IgG antibodies were not detectable by indirect FCM whereas IgA were detected in lower proportions than by direct FCM measurements. Weak correlation was observed between the indirect FCM, indirect MAR, and indirect IBT measurements. CONCLUSION: Nearly all of the IgG and some of the IgA antisperm antibodies in seminal fluid bind to spermatozoa. Thus, indirect tests to measure antisperm antibodies from seminal plasma are likely to miss the presence of antisperm IgG antibodies while detecting some cases of IgA antibodies.

Flow Cytometry↗
PubMed1993

DNA Cytometry Consensus Conference. DNA flow cytometry and breast cancer.

Measurement of cellular DNA content by flow cytometry is capable of detecting aneuploid stemlines, and also of giving an indication of tumor proliferation kinetics by approximating the percentage of cells in S-phase of the replicative cycle. Because it can be applied both to fresh frozen material submitted for steroid hormone receptor analysis and to fixed paraffin-embedded blocks, it is particularly well suited to the study of breast cancer. Despite being a relatively straightforward test which is now widely used in the risk assessment of patients with early breast cancer, in common with many other prognostic markers its precise clinical role remains uncertain. An extensive body of published data has appeared in the last few years, but the results often appear to be inconclusive or contradictory. In order to define the prognostic significance of DNA cytometry in malignant diseases of the breast, large bowel, bladder, prostate, and hematopoietic system, and to clarify some of the technical issues related to clinical laboratory standards and quality controls, a DNA Cytometry Consensus Conference was held in Prout's Neck, Maine, on October 1-4, 1992. This meeting was sponsored by the NCI, the International Society for Analytical Cytology, and industry. The significance of the meeting's conclusions for clinical breast cancer are discussed here. The consensus statement regarding the clinical utility of DNA cytometry in breast cancer, and the Guidelines for the Implementation of Clinical DNA Cytometry which were generated at this meeting, also appear in this issue of Breast Cancer Research and Treatment.

Aneuploidy↗
PubMed1992

Natural killer function in flow cytometry. III. Surface marker determination of K562-conjugated lymphocytes by dual laser flow cytometry.

The recognition of effector cell populations that are able to actively from conjugates with target cells is of major importance in studies of lymphocyte cytotoxicity. A number of methodologies have been described to identify the conjugates and count them, but there have been few studies of the binding capability of the different subsets of effector cells involved in the conjugation phenomenon. Here we describe a methodology that permits the study of two surface markers on lymphocytes conjugated to K562 target cells. In particular, the expression of low density CD8 (CD8dim) has been studied on both CD3+ and CD16+ lymphocytes bound to K562 target cells. Previously described methodologies, either optical microscopy or flow cytometry, were not able to identify the effector population by mAb double staining, especially in the case of antigens expressed at low density. The flow cytometric methodology described here permits the measurement of the binding activity of small lymphocyte subsets such as the CD3+ 8dim+ population. However, the method could be used to study the binding activity of any effector population defined by mAb double staining.

Antigens, Differentiation↗
PubMed1996

DNA image cytometry on sections as compared with image cytometry on smears and flow cytometry in melanoma.

DNA measurements of 130 melanomas were carried out by flow cytometry (FCM) and image cytometry (ICM). ICM was applied to cytological preparations of fresh material (cICM) and to sections of formalin-fixed paraffin embedded tissue (sICM). The DNA ploidy, the DNA index of G0/G1 peaks (DI), and the proliferation index (PI) were used to compare all the methods. The following parameters reflecting malignancy were calculated only from ICM histograms: the 5c exceeding rate (5cER) and the malignancy grade (MG). In cases found to be DNA aneuploid by FCM, the PI values (FCM versus cICM) and the DIs (between all methods) showed a high correlation, and the concordance in relation to the DNA ploidy status was 96% (FCM versus cICM) and 94% (FCM versus sICM). However, we ascertained essential differences between FCM and ICM in melanomas classified as DNA diploid by FCM. The concordance in DNA ploidy was only 66% (FCM versus cICM) and 64% (FCM versus sICM). In contrast, cICM and sICM yielded similar results in most cases. With the exception of the near diploid range, ICM is superior to FCM in detecting DNA aneuploidy. In particular, DNA tetraploid stem lines can easily be overlooked by FCM. Therefore, DNA measurements of tumours judged to be DNA diploid by FCM must be verified by ICM. ICM on sections proved to be applicable and yielded reliable results provided that a suitable thickness was used, and the measuring of sectioned and overlapping nuclei was largely avoided by careful focusing in either direction.

Aneuploidy↗
PubMed1987

Use of DNA image cytometry in addition to flow cytometry for the study of patients with advanced ovarian cancer.

Forty-five patients with advanced ovarian cancer were studied with both DNA flow cytometry (FCM) and automatic DNA image cytometry carried out with the Leiden Television Analysis System (Leytas). There was a significant difference in survival between the diploid and nondiploid cases as determined by FCM. Furthermore, the presence of nuclei with a high DNA content (defined as a DNA content higher than 5C) as determined by Leytas indicated a poor prognosis. When the combined results of FCM and Leytas were taken into account, three different groups of patients could be distinguished. The group of patients with a diploid malignancy (n = 12) had a median survival of more than 60 months. The group of patients (n = 11) with a nondiploid tumor having fewer than 100 nuclei with a high DNA content per 1600 microscope fields formed an intermediate group (median survival, 42 months), whereas the median survival of the remaining patients (n = 22), who had a nondiploid malignancy combined with more than 100 of these nuclei per 1600 microscope fields, was only 15 months. In addition, comparison of the clinical parameters by means of a multivariate analysis (Cox regression model) showed that the combined results of FCM and DNA image cytometry had the largest influence on survival. It is concluded that DNA image cytometry appears to be supplementary to FCM for the study of DNA ploidy abnormalities and that the combined results of these methods have a major influence on the clinical outcome.

Aneuploidy↗
PubMedDate not supplied

Flow cytometry: an overview.

Flow cytometry is an innovative technology that measures certain cell parameters as the cells flow in a fluid stream and in single file past an analytical laser light source. Clinical applications of flow cytometry currently utilized in the laboratory include cell surface antigen determinations or immunophenotyping of hematologic cells, DNA analysis of hematopoietic malignancies and solid tumors, and measurement of CD4 (T helper/inducer cell) absolute counts and T helper/T suppressor (CD4/CD8) ratios in the evaluation of immune deficiency. Flow cytometry often offers a more rapid, sensitive, accurate, and quantitative means of analyzing a particular cell population in a heterogeneous cell suspension as compared to more traditional microscopic methods. This article is intended to provide a general understanding of the technological basis of how a flow cytometer functions as well as an overview of both current and future flow cytometric clinical laboratory applications.

Aneuploidy↗
PubMed2002

[Flow cytometry in immunohematology].

Flow cytometry is an objective, sensitive and quantitative technique which allows rapid and simultaneous analysis of several parameters on a great number of cells. Hence, flow cytometry is particularly suitable for the analysis of complex cell populations, rare events and quantitative studies. In immunohematology, flow cytometry is a very powerful approach to the study of mixed red cell populations (hematopoietic chimerism, transfusion or bone marrow transplantation), the detection of low frequency cell populations (reticulocytes, fetomaternal hemorrhage) and the quantitative analysis of red blood cell antigens.

Blood Transfusion↗
PubMed2001

Flow cytometry in biotechnology.

Flow cytometry is a general method for rapidly analyzing large numbers of cells individually using light-scattering, fluorescence, and absorbence measurements. The power of this method lies both in the wide range of cellular parameters that can be determined and in the ability to obtain information on how these parameters are distributed in the cell population. Flow cytometric assays have been developed to determine both cellular characteristics such as size, membrane potential, and intracellular pH, and the levels of cellular components such as DNA, protein, surface receptors, and calcium. Measurements that reveal the distribution of these parameters in cell populations are important for biotechnology, because they better describe the population than the average values obtained from traditional techniques. This Mini-Review provides an overview of the principles of flow cytometry, with descriptions of methods used to measure various cellular parameters and examples of the application of flow cytometry in biotechnology. Finally, a discussion of the challenges and limitations of the method is presented along with a future outlook.

Animals↗
PubMed2007

Applications of flow cytometry to mycoplasmology.

Flow cytometry has become a valuable tool in different fields of microbiology, such as clinical microbiology, aquatic and environmental microbiology, food microbiology, and biotechnology. It combines direct and rapid assays to determine numbers, biochemical and physiological characteristics of individual cells, revealing the heterogeneity present in a population. This review focuses on the applications of flow cytometry to the field of mycoplasmology. It tries to give a scope of the important breakthroughs which occurred in this field in the last decades, and in the advantages of introducing flow cytometry in research and routine diagnostic procedures of mycoplasmas.

Animals↗
PubMed1985

Heterogeneity of colorectal adenocarcinomas evaluated by flow cytometry and histopathology.

Flow cytometry and histopathology were utilised in evaluating 50 primary and 16 metastatic colorectal carcinomas to determine the influence of heterogeneity and proportion of dying cells on pathological assessments. A new procedure was developed for staining unfixed whole cells with acridine orange and ethidium bromide to quantify DNA and RNA content and number of dead and dying cells. Attempts were made to reduce interobserver variation in histological assessment and to determine whether flow cytometry could refine current grading and staging procedures. Interobserver variation in grading was not improved by estimating proportions of differing grades in multiple samples from individual tumours. Considerable heterogeneity was observed within tumours although this was less apparent when defining ploidy status than histological grade. No consistent differences were observed between superficial and deep parts of tumours or between primary and secondary tumours by either method of analysis. The proportion of dead and dying cells varied widely between tumours but there was no correlation with tumour grade or stage. Non-diploid tumours were not of more advanced stage or poorer histological grade than diploid tumours. Since ploidy status may be an important prognostic factor, analysis of colorectal carcinomas by flow cytometry could be of greater value than conventional grading and staging procedures.

Adenocarcinoma↗
PubMed1988

Interinstitutional variability in DNA flow cytometric analysis of tumors. The National Cancer Institute's Flow Cytometry Network Experience.

Flow cytometric DNA analysis of human urinary bladder specimens may be clinically useful for prognosis in transitional cell (urothelial) carcinoma and for detecting recurrence after treatment. However, many important methodological differences exist among institutions which have described this technique, and it has not previously been shown that data from different institutions are comparable. The National Cancer Institute has created a Flow Cytometry Network to address the need for technology assessment of flow cytometry. This report describes the independent flow cytometric analysis and interpretation of "unknown" paraffin-embedded bladder tumor specimens by the five Network institutions. Although important differences in method existed among the institutions, substantial agreement was achieved in actual data generated and their interpretation. This suggests that a consensus regarding acceptable laboratory performance of this technique could be reached, which should facilitate its more widespread clinical implementation.

Carcinoma, Transitional Cell↗