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Results for “Flow Cytometry”

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PubMed1993

[Study of the cell cycle using flow cytometry in drug allergy].

Drug allergy has been studied by flow cytometry with the technique of cellular cycle, of which the principle is based on cellular activity. There were four groups of patients in the study: The first reference groups (A:20 patients) gave evaluation of phase S + G2-M without antigenic stimulation of monodisperse lymphocyte cultures. This was 4%. The second group (B:15 patients) presented a phase S + G2-M of 14.1% with PHA compared with the reference response significant at 2.5%. The third group (C) was composed of 5 wasp venom allergic subjects with cellular activity phase of 17.3% and 5 nonallergic subjects with an almost identical response of around 15%. The fourth group was 5 subjects who were allergic to drugs with clinical history that strongly indicated an allergy. The response to stimulation in these subjects was much greater for each of the drugs than that of a reference subject who was taking the same drug without problem. Wasp venom seems to behave like PHA, as a mitogen. In contrast, the subjects who were objectively and clinically sensitive to drugs, had an overall greater response to them than those shown by references. It is important to have a control for each drug used.

Adolescent↗

PubMed2006

Flow cytometry evaluation of lead and cadmium effects on mouse spermatogenesis.

Flow cytometry (FCM) is a powerful tool to evaluate cell DNA content and ploidy levels. We have assessed the accuracy of two protocols of nuclei isolation from paraffinized samples (P1 and P2) by comparing FCM results with those obtained using fresh material (F1-F3). After isolation, nuclei were stained with propidium iodide and quantitatively analysed by FCM for changes in germ cell ratios. Results obtained with Protocol P2 were similar to those obtained using the protocol that gave best results for fresh tissues (F2). Protocol P2 was then applied to paraffin embedded testicular samples from ICR-CD1 mice exposed to 1, 2 and 3 mg CdCl(2)/kg bw by single subcutaneous injection, and to 74 and 100 mg PbCl(2)/kg bw administered in four repeated doses. The highest doses of CdCl(2) decreased the number of haploid (1C) cells and increased the number of diploid (2C), S phase and tetraploid (4C) cells. Treatment with PbCl(2) did not induce significant changes in testicular cells subpopulations. These results support the usefulness of FCM in evaluating the effect of toxic substances on mouse spermatogenesis, using both fresh and paraffinized material.

Animals↗

PubMedDate not supplied

[Blood platelet activation markers in patients with acute cerebral infarction during the earliest stage of the disease--evaluation using flow cytometry methods].

Platelet activation seems to play a critical role in a number of vascular diseases, including stroke. The aim of our study was whole-blood flow cytometry evaluation of platelet activation markers: P-selectin (CD62), glycoprotein-53 (CD63) and platelet-derived microparticle in vivo in patients with acute cerebral infarction. We investigated 50 patients (29 men and 21 women, mean age 67.8) with acute cerebral infarction. Parameters of platelet activation were measured on the 1st, 3rd and 7th day after stroke onset. Comparisons were made with 20 control patients matched age. Compared to controls (1.6 +/- 0.7%) the stroke patients showed higher expression of CD62 on the 1st (2.6 +/- 1.4%), 3rd (3.5 +/- 2.3%) and 7th (3.0 +/- 2.0%) day after stroke onset. The differences were statistically significant on all days (p < 0.05). Compared to controls (1.5 +/- 0.6%) the stroke patients had also higher expression of CD63 on the 1st (1.9 +/- 0.6%), 3rd (2.0 +/- 0.6%) day and they showed higher level of platelet-derived microparticles on the 3rd (13.0 +/- 3.0%) day after stroke onset. The differences were statistically significant (p < 0.05). Elevated expression of CD62, CD63 and platelet-derived microparticles level indicate platelet activation during the acute phase of ischaemic stroke. Flow cytometry is a useful tool for in vivo assessment of platelet activation.

Adult↗

PubMed2001

Antifungal susceptibility testing of fluconazole by flow cytometry correlates with clinical outcome.

Susceptibility testing of fungi by flow cytometry (also called fluorescence-activated cell sorting [FACS]) using vital staining with FUN-1 showed a good correlation with the standard M27-A procedure for assessing MICs. In this study we determined MICs for blood culture isolates from patients with candidemia by NCCLS M27-A and FACS methods and correlated the clinical outcome of these patients with in vitro antifungal resistance test results. A total of 24 patients with candidemia for whom one or more blood cultures were positive for a Candida sp. were included. Susceptibility testing was performed by NCCLS M27-A and FACS methods. The correlation of MICs (NCCLS M27-A and FACS) and clinical outcome was calculated. In 83% of the cases, the MICs of fluconazole determined by FACS were within 1 dilution of the MICs determined by the NCCLS M27-A method. For proposed susceptibility breakpoints, there was 100% agreement between the M27-A and FACS methods. In the FACS assay, a fluconazole MIC of <1 microg/ml was associated with cure (P < 0.001) whereas an MIC of > or =1 microg/ml was associated with death (P < 0.001). The M27-A-derived fluconazole MICs did not correlate with outcome (P = 1 and P = 0.133).

Adolescent↗

PubMed2001

Serial evaluation of cell surface markers for immune activation after acute renal allograft rejection by urine flow cytometry--correlation with clinical outcome.

BACKGROUND: The use of urine flow cytometry (UFC) as a noninvasive tool for the diagnosis of acute and chronic rejection of the renal allograft has been previously reported. METHODS: We analyzed the expression of various cell surface antigens during a 30-day period after the diagnosis and treatment of 24 acute rejection (AR) episodes. UFC was performed on 59 urine specimens, from 17 patients meeting the diagnostic criteria for AR. UFC analysis was performed blinded to the clinical management utilizing the following fluorescinated monoclonal antibodies: anti-CD3, anti-CD14, anti-HLA-DR, anti-CD54, and anti-interleukin 2 receptor. Results were correlated with the patient's requirement for antilymphocytic drugs and increment in serum creatinine level (mg/dl) on day 30 after AR. RESULTS: HLA-DR was the most prevalent antigen noted during the first 2 days of AR (91.7% of the samples), followed by CD14 (50%) and CD54 (41.7%). After day 4 the degree of expression of HLA-DR-, CD14-, and CD54-positive cells correlated with the need for antilymphocytic drugs. CD54 was the best parameter with a sensitivity=100% and specificity=90.9% (P=0.001). Those patients who had permanent graft injury after treatment of the AR had persistence of CD54- and CD14-positive cells in the urine. CONCLUSION: Serial monitoring of urine sediments by UFC was predictive of the requirement for antilymphocytic therapy and irreversible graft damage.

Adolescent↗

PubMed1988

Flow cytometry shows recurrent aneuploid clone after remission in megakaryocytic leukemia.

Flow cytometry using a DNA label can quantitate aneuploid clones in malignant tissue. We illustrated the clinical value of this technique in a 71-year-old woman with acute megakaryocytic leukemia, which was diagnosed by staining of the blasts with factor VIII antigen and their morphologic resemblance to megakaryoblasts. Marrow cells were removed from needle biopsies by vortexing in RPMI medium, centrifuged in Ficoll-Hypaque, stained with a propidium-iodide/NP-40 mixture, and analyzed at 488 nm using an argon laser. During 3 weeks of low-dose cytosine arabinoside (ara-c) infusion therapy, hyperdiploid peak A dropped from 35% (day 0) to 2.3% (day 14) to 0% (day 21), with development of marrow hypoplasia. Similarly, hyperdiploid peak B, went from 7.6% to 9.1% to 3.5%. Subsequently, her marrow recovered normal morphology and lost the aneuploid peaks. Her blood counts recovered to near normal. Four months later, she relapsed and had a return of the day-21, incompletely eradicated peak B. There was no evidence of peak A. Repeated treatment with ara-c resulted in temporary suppression of the disease, but she died 3 months later with progressive hepatosplenomegaly. Analysis of cells from her enlarged liver, heavily infiltrated with blasts, showed a large hyperdiploid peak B. In this patient, ara-c therapy induced a remission with permanent eradication of one clone, but incomplete eradication of a second clone, which ultimately led to her relapse and death.

Aged↗

PubMed1990

Immunogold probing of platelet factor 4 in different ploidy classes of rat megakaryocytes sorted by flow cytometry.

Different ploidy classes of rat megakaryocytes were sorted by flow cytometry from highly purified perfusion-fixed megakaryocyte cell suspensions prepared by sequential centrifugal elutriation and Percoll gradient centrifugation. Sorted cell populations were studied for the localization of platelet factor 4 (PF-4) probed with the monoclonal antibody 2E7 in order to clarify the relevance of PF-4 localization to the cytoplasmic and nuclear development of megakaryocytes. The relative numbers of labeled alpha granules and labeled alpha granule-related small vesicular structures (AGR-SVS) were quantitated using the gold-labeled antibody detection method and correlated with DNA content and cytoplasmic maturation in individual megakaryocytes. We determined that the stage of cytoplasmic maturation exerted a significant effect on the proportion of labeled alpha granules and labeled AGR-SVS. A significant interaction effect of stage and ploidy class resulted in the stage effect on proportion of labeled alpha granules being significant only in two of the three ploidy classes. The least mature cells present within each ploidy group exhibited PF-4 labeling mostly in SVS that were not related to alpha granules. During subsequent cytoplasmic maturation, more of the labeled SVS were seen related to alpha granules, with more of the mature alpha granules themselves becoming labeled. Polyploidization also affected the proportion of labeled AGR-SVS. Our data suggest that SVS play a role in the intramegakaryocytic transport of PF-4 into alpha granules. These data provide evidence of the complexity of megakaryocytic differentiation involving both cytoplasmic maturation and nuclear endoreduplication as reflected in PF-4 expression.

Animals↗

PubMed1997

Flow cytometry CD45 gating for immunophenotyping of acute myeloid leukemia.

A flow cytometry method has been introduced into the routine investigation of whole bone marrow samples following red blood cell lysis on the basis of a primary CD45/side scatter (SSC) gating procedure. Blast cells were first identified by CD45/SSC gating in 74 cases of acute myeloid leukemia (AML) and the results were compared to a conventional FSC/SSC gating procedure and to MGG-staining smears. The percentages of blast cells in these samples as defined by the morphological analysis of MGG smears correlated better with the values determined by CD45/SSC gating (r = 0.94) than with the blast cell counts recorded with FSC/SSC gating (r = 0.76). These findings were not surprising because while CD45 expression was regularly lower on leukemic blasts than on normal lymphoid and monocytic cells, the FCS/SSC characteristics of these populations were overlapping. In 53 samples, the blast cell populations were also analyzed with a panel of FITC-conjugated monoclonal antibodies that were utilized in double labeling with CD45-PE. We show that the CD45/SSC gating procedure improved phenotypic determination of the blast cells in three ways: (1) by discriminating between leukemic blast cells and residual normal cells; (2) by excluding normal cells from the phenotypic analysis of leukemic blast cells; and (3) by identifying blast cell heterogeneity in many cases of leukemia on the basis of different CD45 display. Moreover, this immunophenotyping procedure on whole bone marrow samples also allowed an efficient discrimination between the various cell lineages and facilitated the analysis of leukemic blasts present in low proportions.

Acute Disease↗

PubMed1982

Artifacts associated with mithramycin fluorescence in the clinical detection and quantitation of aneuploidy by flow cytometry.

Ethanol-fixed cells stored at 4 degrees C exhibit fixation time-dependent hyperchromatism in comparison with freshly fixed cells when stained with mithramycin and examined by flow cytometry. This hyperchromatism has been found to be temperature-dependent, developing fully within 72 hr at room temperature, and within 2 hr at 37 degrees C. Cells from normal donors that are stained with mithramycin exhibit spurious aneuploid peaks. These spurious aneuploid peaks can be eliminated by incubating ethanol-fixed cells at 37 degrees C for 2 hr prior to staining; true aneuploidy is not affected by this procedure. In rare instances, cytoplasmic fluorescence can be observed in mithramycin-stained cells. In addition, unexplained hypochromatism and hyperchromatism can be observed in some clinical samples, particularly in human melanoma. The effects of these unexplained staining artifacts can be minimized or eliminated by adopting strict criteria for the clinical detection of aneuploidy by flow cytometry.

Aneuploidy↗

PubMed1997

[Use of flow cytometry in evaluation of cellular changes in interstitial lung diseases].

Flow cytometry (FC) usefulness for pulmonary reactive cell changes examination in interstitial lung diseases was assessed. Bronchoalveolar lavage (BAL) lymphocyte direct (two-color and three-color) phenotyping was carried out in 63 patients with sarcoidosis (subdivided according to the disease radiological stage and smoking status), 23 patients with systemic sclerosis (SSc) and 12 individuals exposed to silica dusts. 33 healthy volunteers were used as controls. Routine BAL cytology and peripheral blood lymphocyte (PBL) typing was performed in all tested subjects. FC results quality control was performed according to BD Simultest IMK Plus criteria (for PBL) modified by the author. The conventional lymphocytic gate (PBL light scatter based) was excluded, as the source of error in L-BAL subset analysis. Two-color L-BAL phenotyping and alveolar lymphocyte CD45FITC/SSC gating was found to be usually sufficient. However, in poor-lymphocyte materials (e.g. in healthy smokers) three-color method, using anti-CD45 PECy5 monoclonal antibody for staining each patient sample, should be considered. No significant changes in lymphocyte subsets were found in FC as compared with alkaline phosphatase immunocytochemical method. The prevalence of CD3+ cells with only a few lymphocytes expressing NK (CD3-CD16 or 56+), T suppressor (CD8+ 11b+) or B cell phenotype--as compared with PBL, was found in BAL of all examined subjects. CD8+ cell subset was dominated by T cytotoxic cell phenotype (CD8+ CD11b-) in all tested groups. L-BAL T cells expressed sensitized memory cell phenotype--CD4+ (CD8+)CD45RO+ in sarcoidosis, SSc and controls (the staining not performed in silica exposed persons). Characteristic BAL cytological and immunological pattern (lymphocytic alveolitis, increased CD4/CD8, high CD3(CD4)+HLA-DR+ percentage) was observed in pulmonary sarcoidosis. SSc patients showed reduced BAL CD4/CD8 ratio, due to T cytotoxic cell predominance (the changes were more distinct in the group with clinical pulmonary changes). Early activation marker (CD25) was expressed on the elevated percentage of BAL T helper cells in SSc. High CD4+CD25+ cell percentage was the most characteristic sign of lymphocyte activation in individuals exposed to silica. Summing up, the reference values for L-BAL subsets were proposed. CD4/CD8 ratio alterations in interstitial lung disorders should be interpreted as the local imbalance between T helper memory cells and sensitized T cytotoxic lymphocytes. FC characterization of alveolar lymphocytes provides insight into the pathogenesis of pulmonary diseases.

Adult↗

PubMed2005

[Application of flow cytometry on functional assessment of health food].

OBJECTIVE: To establish flow cytometry (FCM) methods and evaluate their application value for measuring the index for enhancing immune function of health food. METHODS: In mice experiment model, the dosage groups were respectively oral fed with three test substances according to 5, 10, 30 times of the recommended dose for human body; both the negative and positive control groups were fed with equivalence purified water once a day. The positive control was fed with 25 mg/kg body weight levamisole for 3 days before finishing the administration, and the immune two percent of sheep erythrocytes were administrated at the last day. In rats experiment model, the test substance was given by mixing feed according to 25 and 50 times of the recommended dose for human body. At the end of the experiment, indices below were simultaneously detected. (1) The classical indices included: spleen lymphocyte transformation test by using ConA (MTT assay); spleen NK cell activity test (LDH assay); delayed-type hypersensitivity test by using sheep erythrocyte (foot palm thickening) method and phagocytosis activity tested by mice peritoneal macrophages. (2) FCM indices included: T and B lymphocytes quantitating in mice peripheral blood, activated antigen expression level in the surface of T lymphocytes and NK cells and phagocytosis activity for fluospheres in mice peritoneal macrophages. RESULTS: (1) Compared with the negative control group, there were no significant differences in T and B lymphocytes proportion and the number of lymphocytes in mice peripheral blood after given 0.83, 1.67, 5.01 g/kg protein powder; (2) mice peripheral blood T lymphocyte sub-cluster CD(69)(+)/CD(3)(+) of 3.75, 7.50, 15.0 ml/kg bw Cen-Rong Cream groups were all significantly increased (P < 0.05), which were shown a good coherence with the classic test index; (3) mice peripheral blood NK cell sub-cluster CD(69)(+)/NKG2D(+) of 0.83, 1.67 g/kg protein powder groups were both significantly increased (P < 0.05), which was kept in good coherence with those of NK cell activity test (LDH assay); rats peripheral blood NK cell sub-cluster CD(161a+)/CD(25)(+) of 1.50 g/kg ganoderma lucidum and cordycepicmycelia group was significantly increased (P < 0.05); (4) the phagocytosis activity in mice peritoneal macrophages: there were no significant difference found between the controls and the dosage groups in the classic test. However, in the FCM test, the percentage of phagocytic cells of 0.15, 0.30, 0.90 g/kg ganoderma lucidum and cordycepicmycelia groups and the phagocytic index of 0.30, 0.90 g/kg were enhanced. CONCLUSION: It suggests that was shown in detecting and assessing enhancing immune function of health food the results tested by FCM were fairly consistent with those by using traditional methods, most of them would have higher sensitivity. It should be valuable to applying FCM in the measurement and assessment of enhancing immune function of health food and worth while to further study as to enlarging its application.

Animals↗

PubMed1994

Measurement of ceroid accumulation in macrophages by flow cytometry.

The accumulation in macrophages of ceroid, an autofluorescent polymer composed of oxidised protein and lipid, can be monitored semiquantitatively by staining techniques. However, such methods are crude and give little information about the amount of ceroid within cells. Flow cytometry, however, can give a quantitative assessment of cellular ceroid accumulation in vitro. Recently, flow cytometry was explored as a method for measurement of the accumulation in macrophages of ceroid. The accumulation appeared to be diminished in the presence of the antioxidant, alpha-tocopherol. This is consistent with the role of lipoprotein oxidation in ceroid accumulation. Here the optimum wavelengths of emission and excitation, using both conventional fluorescence spectroscopy of cellular ceroid and flow cytometric measurements with a number of optical filters, are determined. The use of optimal wavelengths determined in these studies enhances overall sensitivity. The findings are discussed in the context of future investigation of cell-mediated lipid oxidation and its potential antagonists.

Animals↗

PubMed1988

Erythropoietic protoporphyria: a quantitative determination of erythrocyte protoporphyrin in individual cells by flow cytometry.

A fraction of the erythrocytes from patients with erythropoietic protoporphyria contains large amounts of protoporphyrin. By extraction methods, only a mean value of the protoporphyrin content in erythrocytes is obtained. In this study, flow cytometry was used to determine the protoporphyrin content in each individual erythrocyte. The mean erythrocyte protoporphyrin fluorescence, calculated from flow cytometric data, correlated linearly to the mean cellular protoporphyrin concentration measured by ethyl acetate/acetic acid extraction. This indicates that flow cytometry gives a reliable quantitative determination of protoporphyrin in individual cells. Erythrocytes from patients with erythropoietic protoporphyria had a markedly skewed distribution of protoporphyrin. In the most fluorescent erythrocytes (protoporphyrin concentration 3.3 mM), there was about one protoporphyrin molecule for every sixth haeme molecule. This might explain the slight anaemia in some of these patients.

Erythrocytes↗

PubMed2001

Cell proliferation in colorectal adenocarcinomas: comparison between Ki-67 immunostaining and bromodeoxyuridine uptake detected by immunohistochemistry and flow cytometry.

We compared three different means of assaying tumor proliferative activity in 30 human colorectal adenocarcinomas labeled in vivo with bromodeoxyuridine (BrdUrd). The labeling indices (LI) of BrdUrd obtained both by flow cytometry (FCM) and immunohistochemistry (IH) were also compared with the labeling index of Ki-67. These methods were then related to tumor ploidy and pathological features. Flow cytometry was performed in accordance with Begg's method after intravenous infusion of BrdUrd four hours before surgery. Immunohistology was carried out on paraffin-embedded sections with monoclonal antibodies against BrdUrd and Ki-67. A positive correlation was found between BrdUrd LI obtained by both FMC and IH (p<0.0001), a finding that complies with the literature. However, we report on a correlation between Ki-67 LI and BrdUrd LIs in colorectal tumors (p=0.012). The results were valid for all tumors when they were subdivided into diploid and aneuploid groups. The labeling indices were significantly higher in the aneuploid tumor group than in the diploid group (p=0.047). No relationship between proliferation parameters and tumor stage or grade was found. To our knowledge, this is the first report on a positive correlation between tumor proliferation indices in BrdUrd LIs and Ki-67 in colorectal carcinomas. This finding validates the value of Ki-67 immunostaining, which, however, should be confirmed in a larger series under the same technical conditions.

Adenocarcinoma↗

PubMed1990

[Detection of anti-sperm antibodies on the surface of live spermatozoa by the method of flow cytometry].

Detection of antisperm antibodies is an important step of the diagnosis of infertility. In present study we conducted comparative studies with the detection of antisperm antibodies in IgG, IgA and IgM classes on the surface of living spermatozoa by flow cytometry and with Mixed Agglutination Reaction and Sperm immobilization. Our data show that flow cytometry may be used to verify that immunoglobulins are on the surface of living spermatozoa, either retrieved directly from an ejaculate or following exposure to cervical mucus or serum and to determine their isotype, proportion of sperm which bound antibody and quantity of immunoglobulins bound to cell surface.

Animals↗

PubMed1997

Altered lymphocyte antigen expressions in HIV infection: a study by quantitative flow cytometry.

To identify surface antigen changes that may contribute to the immune deficiency in infection with the human immunodeficiency virus (HIV), we quantified, by double-staining flow cytometry, the number of antigens of the main peripheral blood lymphocyte subsets from 30 HIV-positive persons and compared them with those of 19 HIV-negative healthy donors. Standard microbeads with different capacities to bind mouse immunoglobulins were used to convert the mean fluorescence intensity values into numbers of antigen molecules per cell, measured as antibody binding capacity. The level of expression of different lymphocyte antigens in HIV-infected patients differs from that seen in normal blood lymphocytes. Some of these surface markers are decreased, whereas others are increased, and their expression is modulated depending on the specific cell subset considered. The expression of CD3, CD4, and CD8 on T lymphocytes is significantly decreased; moreover, CD3 is down-regulated on activated and nonactivated T lymphocytes and on CD4 and CD8 cells. In contrast, the expression of CD2 on T cells is significantly increased. Natural killer cells exhibit down-regulation of CD7, normal levels of CD8 and CD56, and overexpression of CD2. Our results also identified, for most of these antigens, quantitative differences in membrane expression according to different disease stages, as assessed by the CD4 T-cell count. Quantitative flow cytometry therefore may provide useful insights into the lymphocyte functional defects characterizing HIV infection.

Adult↗

PubMed1993

Application of flow cytometry to rapid microbial analysis in food and drinks industries.

In food and drinks industries, the time required for conventional tests can lead to substantial delays in product release to the market. Flow cytometry (FCM) has been used in conjunction with viability markers for rapid counting of yeast, mould and bacterial cells in food products. A single-parameter flow cytometer has proved applicable to the rapid detection of low numbers of microbial contaminants in finished products. The excellent correlation between FCM results and product quality shelf-life expiry date has allowed the establishment of realistic quality control criteria for rapid positive release of product. Used for the monitoring of microbial biomass during manufacturing processes, flow cytometry allowed a direct assessment of bacterial growth. The reproducibility of the results and the proven correlation with standard plate count method obtained in industrial conditions make FCM a good predictive method for product and process quality control.

Bacteria↗

PubMed1990

Genome elimination in diploid and triploid Rana esculenta males: cytological evidence from DNA flow cytometry.

Cytological aspects of hemiclonal (meroclonal) inheritance in diploid and triploid males of the hybridogenetic frog Rana esculenta (Rana ridibunda x Rana lessonae) have been studied by DNA flow cytometry. The fact that the R. ridibunda genome contains 16% more DNA than the R. lessonae genome provides the ability to discern cells containing genomes of any species from the water-frog complex under study. Data are presented showing that elimination of the R. ridibunda genome occurs in hybridogenetic males from certain populations. In triploid males, the cytogenetic mechanism of hemiclonal inheritance is simpler than in diploids: after the elimination of a genome (always the genome in the minority in the triploid set; "homogenizing elimination"), no compensatory duplication of the remaining genetic material is necessary, as it is in diploids. The process of elimination can be visualized in triploid males by using DNA flow cytometry to identify cells in the special phase of the spermatogonial cell cycle that we termed the E phase.

Animals↗