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Results for “Flow Cytometry”

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PubMed1986

[Application of flow cytometry to the diagnosis of bladder carcinoma].

DNA histograms obtained by flow cytometry (FCM) in patients with bladder tumor were analyzed. DNA histogram pattern and calculated proliferation index (PI) can be used to evaluate the presence or the absence of tumor cells and this technique can be applied to the automated cytology in patients with bladder tumor. Furthermore flow cytometry is considered to provide us with useful information about the malignant potential of the tumor as well as the effect of the treatment. In the follow-up examination, our results suggest that flow cytometry may be a valuable addition to the routine urological examination in the conservatively treated patients with superficial bladder tumors.

Cytodiagnosis↗

PubMed1996

Detection of canine erythrocytes infected with Babesia gibsoni by flow cytometry.

Peripheral blood samples from dogs infected with Babesia gibsoni were analyzed by flow cytometry for parasitized erythrocytes after staining with hydroethidine. Cells identified as positive by flow cytometry were erythrocytes infected with B. gibsoni. Analysis of 26 samples by flow cytometry for % parasitemia revealed a correlation coefficient of 0.97 in comparison to the conventional method of light microscopy.

Animals↗

PubMed1989

Simultaneous determination of absolute total lymphocyte and CD4+ lymphocyte levels in peripheral blood by flow cytometry.

A distinguishing feature of the Spectrum III flow cytometer is its capacity to analyze a constant volume of cell suspension. The authors have capitalized on this feature to directly and simultaneously measure the absolute numbers of all lymphocytes and CD4+ lymphocytes per microliter of peripheral blood. The study group consisted of 42 hospital patients, 12 former blood donors seropositive for human immunodeficiency virus (HIV), and 12 HIV-seronegative donors. Regression analysis revealed a highly significant correlation (r = 0.97) between Spectrum lymphocyte counts and lymphocyte counts determined by a Coulter Counter S-Plus IV. Similarly, Spectrum CD4 cell counts were significantly correlated (r = 0.98) with CD4 cell counts calculated from the Coulter lymphocyte counts and % CD4+ lymphocytes determined by flow cytometry. These findings indicate that the absolute numbers of lymphocytes and subsets of lymphocytes in peripheral blood can be rapidly and simultaneously measured by flow cytometry. Such an assay should prove useful in studies of HIV infection, where total lymphocyte and CD4 cell levels are important parameters for clinical staging and assessing responses to treatment.

CD4-Positive T-Lymphocytes↗

PubMedDate not supplied

Cell kinetic analysis in pediatric brain and spinal tumors: a study of 117 cases with Ki-67 quantitation and flow cytometry.

We present cell kinetic data including Ki-67 quantitation and flow cytometry on 117 pediatric brain/spinal cord tumors and review the literature. Although, in general, these proliferation indices are in agreement with the histologic grade, they are useful in prognostication in some instances when the histological features of malignancy are equivocal. Specific examples in which flow cytometry may prove particularly useful in this context are childhood ependymomas, which do not show frank anaplasia but have cellular foci with focal increase in mitoses, and choroid plexus neoplasms, where elevated S phase fractions have been associated with an adverse outcome. Thus Ki-67 quantitation and flow cytometry not only serve as useful adjuncts to conventional histologic grading but also in specific instances may provide new information on tumor prognosis.

Brain Neoplasms↗

PubMed2003

Antifungal susceptibility testing of Candida albicans by flow cytometry.

Antifungal susceptibilities of 28 Candida albicans isolates and two quality control strains to amphotericin B and fluconazole were determined by flow cytometry and microdilution method. Minimum inhibitory concentrations (MICs) obtained by flow cytometry were compared with the results obtained by The National Committee for Clinical Laboratory Standards Subcommittee (NCCLS) broth microdilution method. The agreement of results (within two dilution) obtained was found as 96 and 93% for amphotericin B and fluconazole, respectively. At least 24 h incubation was required for reading the microdilution assays. Four hours of incubation was required for fluconazole, whereas 2-h incubation was sufficient for amphotericin B to provide MIC by flow cytometry. Results of this study show that flow cytometry provides a rapid and sensitive in vitro method for antifungal susceptibility testing of Candida albicans isolates.

Amphotericin B↗

PubMed1994

[Evaluation of the reproducibility of automated monocyte counting using flow cytometry and monoclonal antibodies].

PURPOSE: To compare the results of the monocyte count provided by autoanalysers with those attained with flow cytometry. MATERIAL AND METHODS: Fifty-six blood samples (EDTA-K3) from the emergency laboratory were studied. The automatic percentage of monocytes attained by four autoanalysers, STKS (Coulter-IZASA), Technicon H*2 (Bayer Diagnostics), Cell-Dyn-3000 (Abbott Diagnostics) and NE-8000 (TOA-Sysmex) was confronted with that provided by the flow cytometry analysis performed with a FACScan (Becton-Dickinson) using monoclonal antibodies of myeloid-monocytic lineage (CD14, CD16). The morphologic observation of the blood smear in accordance with the H20-A protocol of the National Committee for Clinical Laboratory Standards (NCCLS) was used as a reference method. Descriptive statistics plus linear regression analysis, along with the Student's t test for paired data were used for the statistical evaluation of the results. RESULTS: Significant correlation was found between the systems under study and the flow cytometry method: Technicon H*2 (y = 1.79 +/- 0.61x; r = 0.91, p < 0.0001), Coulter STKS (y = 0.61 +/- 0.93X; r = 0.89, p < 0.0001), Cell-Dyn 3000 (y = 0.88 + 0.64x; r = 0.78, p < 0.0001) and Sysmex NE-8000 (y = 4.60 +/- 0.33x; r = 0.52, p < 0.0001). When comparing the percentage of monocytes by means of the Student's t test it was found that Coulter STKS provided the closest results with regard to flow cytometry (13.78 +/- 9.27 vs 14.19 +/- 8.88, p = 0.49), while the closest findings with respect to the reference method were given by Technicon H*2 (9.29 +/- 4.78 vs 9.71 +/- 4.77, p = 0.30). CONCLUSIONS: From this analysis, it was concluded that flow cytometry could be an alternative method to conventional optic observation in the evaluation of the differential count of leucocytes, including monocytes.

Antibodies, Monoclonal↗

PubMed1987

[Diagnostic value of flow cytometry of bladder lavage in the surveillance of bladder tumors].

DNA index and proliferation index (% greater than 2 n) of 125 bladder washings were studied with flow cytometry. Cystoscopy was positive in 49 patients and negative in 56 patients with a previous history of bladder cancer. There were 20 control patients with a normal bladder. Flow cytometric data was compared with cystoscopic and cytologic data. In the group of 49 patients with a positive cystoscopy, conventional cytology was suspicious or positive in 70% (34/49) whereas flow cytometry was positive in only 43% of the cases (21/49). The diagnostic sensitivity of flow cytometry increased with grade elevation: 7% of grade 1 tumors, 43% of grade 2 and 77% of grade 3 had a positive flow cytometric examination. In the group of 56 patients with a negative cystoscopy, flow cytometry was positive in 36% of the cases and cytology in 6% of the cases. The diagnostic sensitivity of flow cytometry was rather disappointing in the study on bladder washings. Flow cytometric follow-up of bladder washings should be reserved preferentially to patients with a poor prognosis, i.e., superficial bladder cancer with an aneuploid DNA content.

Cystoscopy↗

PubMed1999

Benign, preinvasive and invasive ductal breast lesions. A comparative study with quantitative techniques: morphometry, image- and flow cytometry.

The histological distinction between ductal hyperplasia of the breast, atypical ductal hyperplasia and ductal carcinoma in situ is difficult and subjective. To gain a better understanding of these lesions, we performed a comparative study comprising 20 cases of ductal hyperplasia without atypia, 20 cases of ductal hyperplasia with atypia, and 30 cases of ductal carcinoma in situ (well-, moderately- and poorly-differentiated), using quantitative techniques: image cytometry analysis, morphometry and DNA analysis, and DNA flow cytometry. Our results confirm that the mean nuclear area and volume progressively decreased from ductal carcinoma in situ to ductal hyperplasia without atypia. The difference was significant (p < 0.05) when comparing hyperplasia without atypia with hyperplasia with atypia and hyperplasia with atypia with poorly differentiated ductal carcinoma in situ. Atypical ductal hyperplasia values were comparable to those of well-differentiated ductal carcinoma in situ. DNA image cytometry proved significant (p < 0.05) when comparing hyperplasia without atypia with hyperplasia with atypia and hyperplasia with atypia with moderately- and poorly-differentiated ductal carcinoma in situ. DNA flow cytometry revealed significant differences only in the distribution of the DNA ploidy patterns (p < 0.05) when comparing hyperplasia without atypia with moderately- and poorly-differentiated DCIS. A comparison of the results obtained by image and flow cytometry showed that in 90% of the cases the IC and FC values were coincident, whereas in the remaining cases the DNA index was aneuploid by IC and diploid by FC.

Breast Neoplasms↗

PubMed1996

[Importance of flow cytometry in the detection of anti-erythrocyte autoantibodies].

Coombs test and flow cytometry have been compared in terms of specificity and sensibility in a population of hospitalized patients, for whom a Coombs test had been required. The Coombs test seems more sensible than flow cytometry to detect red cell-bound IgG. For a given patient and over the time, flow cytometry seems better correlated with the severity of haemolysis if erythrocytes are strongly sensitized by IgG. The results of flow cytometric analysis, in percentage of sensitized erythrocytes, do not allow to define a sensibilization threshold for haemolysis prediction. Flow cytometric analysis would be more sensible than Coombs test in the detection of red cell-bound C3d, but these cases are not associated with autoimmune haemolytic anemia. Direct Coombs test should remain the diagnostic test of autoimmune haemolytic anemia.

Autoantibodies↗

PubMed2003

Flow cytometry assessment of bacterioplankton in tropical marine environments.

Flow cytometry was used to characterize bacterioplankton from two tropical environments in Brazil: the eutrophic Guanabara Bay and the oligotrophic southwest Atlantic Ocean. Bacterial abundance was evaluated by flow cytometry, and cells were stained with SYTO 13, allowing demonstration of differences in nucleic acid content. Bacterial production was also evaluated by means of 3H-leucine incorporation. Bacterial numbers were different for both sites. In Atlantic Ocean samples, we found a maximum of 5.50 x 10(5) cells ml(-1), and low nucleic acid content organisms predominated. In Guanabara Bay, bacterial numbers were one order of magnitude higher than in the ocean, and they varied from outer bay (1.01 x 10(6) cells ml(-1)) to inner bay (6.90 x 10(6) cells ml(-1)). Bacterial activity in ocean samples varied from 4.6 to 126 ng C l(-1) h(-1), while in the bay, mean values ranged from 1.95 microg C l(-1) h(-1) (outer bay) to 7.35 microg C l(-1) h(-1) (inner bay). Values found for both parameters are characteristic of different trophic situations. These results illustrate the utility of cytometric analyses of bacterioplankton populations in characterizing their large spatial and temporal scales of distribution in aquatic ecosystems.

Atlantic Ocean↗

PubMedDate not supplied

Flow cytometry: its applications in hematology.

The techniques of flow cytometry are becoming more and more important for the clinical hematology laboratory. No longer a novelty confined to a few specialized institutions as it was 10 years ago, flow cytometry has blossomed into a mature discipline. The methodology is well-known, the mechanical apparatus is readily available, and the role it plays in clinical hematology is increasingly appreciated. The burgeoning number of scientific articles devoted to this topic attests to the interest it has aroused as a tool for both medical research and patient care. In fact, more than a thousand such papers are now published each year and it would be impossible to deal with all the methodologies and applications of FCM currently utilized or under development. Throughout this paper four relevant hematologic fields are briefly discussed, in which FCM appears to be of great help at present: the immunophenotyping of leukemias and lymphomas, the measurement of proliferative activity and DNA ploidy in hematological malignancies, the detection of drug resistant leukemic cells and the use of FCM in the study of platelets.

Flow Cytometry↗

PubMed1989

[Evaluation of testicular damage by flow cytometry: testicular atrophy caused by ethylene oxide].

The new method using flow cytometry was applied to analyse the testicular toxicity of ethylene oxide, and the usefulness of this method is discussed. When Wistar male rats were exposed to ethylene oxide for six hours a day, three times a week for six weeks, the testicular weights of the exposed group significantly decreased. When the cells of these testes were stained by propidium iodide and analysed by flow cytometry, four peaks which corresponded to maturation phase spermatids (less than C), the other haploid cells (C), diploid cells (2C) and tetraploid cells (4C) were obtained. Calculating the ratio of the percentage of less than C, C and 4C to that of 2C, the ratio of less than C of the exposed group decreased by 72.9%, 2C by 53.5% and 4C by 5.1% when compared with the control group. As these changes were almost consistent with that of histopathological examinations, we are able to conclude that more mature germ cells were affected by ethylene oxide. This method by flow cytometry is thought to be objective, quantitative and convenient to evaluate testicular damage by chemicals.

Administration, Inhalation↗

PubMedDate not supplied

Applications of flow cytometry to hematopoietic stem cell transplantation.

Applications of flow cytometry to clinical and experimental hematopoietic stem cell transplantation (HSCT) are discussed in this review covering the following topics: diagnosis and classification of lymphohematologic disorders, quantitation of hematopoietic progenitors in the graft, lymphohematopoietic reconstitution following HSCT and animal models of human HSCT. At the end, the utilization of flow cytometry in clinical HSCT by Brazilian transplant centers is briefly reviewed.

Animals↗

PubMed2006

[Application of multiparameter flow cytometry in diagnosis of non-Hodgkin lymphoma].

OBJECTIVE: To evaluate the role and application of flow cytometry in the diagnosis of non-Hodgkin lymphoma (NHL). METHODS: Fresh cell samples from 40 cases of lymphoproliferative disorders were obtained by fine needle aspiration or excisional biopsies. Multiparameter flow cytometry was used to study the surface antigens of lymphoid cells. The immunophenotyping results were also correlated with morphologic features seen in the cytology preparations. RESULTS: Of the 40 cases with histologic diagnosis of NHL, 37 cases (92.5%) had the lymphoma diagnosis confirmed by this method. The concordance rate for the 20 cases of B-cell NHL was 100%. As for the 17 cases with histologic diagnosis of T-cell NHL, 12 cases (66.7%) were correctly diagnosed as T-cell NHL using flow cytometry, while 2 cases (11.8%) were interpreted as B-cell NHL and the remaining 3 cases (17.6%) were undiagnosed. CONCLUSION: Immunophenotyping by flow cytometry can serve as an ancillary technique in diagnosis and subclassification of NHL.

Adolescent↗

PubMed2001

The significance of bivariate cytokeratin and DNA flow cytometry in paraffin-embedded specimens of non-small cell lung cancer.

BACKGROUND: The presence of non-tumor cells inside cancer tissue is one of the causes of errors in cell cycle analysis by DNA flow cytometry. The recent establishment of bivariate cytokeratin and DNA flow cytometry has made feasible the accurate assessment of tumor proliferative activity. METHODS: Bivariate flow cytometry and immunohistochemistry examinations of paraffin-embedded specimens were performed in 92 patients with non-small cell lung cancer (NSCLC). Determination of the S-phase fraction by flow cytometry, with cytokeratin gating (CK-gated SPF) and without gating (ungated SPF), and the expression of proliferating cell nuclear antigen by immunohistochemistry (PCNA labeling index), were used to assess cancer cell proliferation. RESULTS: Two tumors had DNA histograms with a coefficient of variation of more than 8.0% and were excluded from the flow cytometric analysis. In DNA diploid tumors (n = 25), the ungated SPFs (8.7 +/- 3.6%) showed a lower distribution than the CK-gated SPFs (14.3 +/- 4.7%) (P < 0.0001). In DNA aneuploid tumors (n = 65), there was no difference in distribution between the ungated SPFs (15.0 +/- 8.3%) and the CK-gated SPFs (15.1 +/- 7.1%) (P = 0.94). The CK-gated SPF and the PCNA labeling index of an individual tumor had a good correlation (P < 0.0001), and this agreed with the result showing that DNA diploid and aneuploid tumors had equal proliferative activity (P = 0.64 and P = 0.63, respectively). CONCLUSION: The technique using CK-gating markedly improved the SPF measurement in DNA diploid tumors. This assessment showed no difference in proliferative activity between DNA diploid and aneuploid tumors in NSCLC. Bivariate cytokeratin and DNA flow cytometry is an accurate and objective method for cancer-specific analysis, and will surely be informative in clinical oncology.

Adult↗

PubMed2001

Plug flow cytometry extends analytical capabilities in cell adhesion and receptor pharmacology.

BACKGROUND: Plug flow cytometry is a recently developed system for the automated delivery of multiple small boluses or "plugs" of cells or particles to the flow cytometer for analysis. Important system features are that sample plugs are of precisely defined volume and that the sample vessel need not be pressurized. We describe how these features enable direct cell concentration determinations and novel ways to integrate flow cytometers with other analytical instruments. METHODS: Adhesion assays employed human polymorphonuclear neutrophils (PMNs) loaded with Fura Red and Chinese hamster ovary (CHO) cells cotransfected with genes for green fluorescent protein (GFP) and human P-selectin. U937 cells expressing the human 7-transmembrane formyl peptide receptor were loaded with the fluorescent probe indo-1 for intracellular ionized calcium determinations. A computer-controlled syringe or peristaltic pump loaded the sample into a sample loop of the plug flow coupler, a reciprocating eight-port valve. When the valve position was switched, the plug of sample in the sample loop was transported to the flow cytometer by a pressure-driven fluid line. RESULTS: In stirred mixtures of PMNs and CHO cells, we used plug flow cytometry to directly quantify changes in concentrations of nonadherent singlet PMNs. This approach enabled accurate quantification of adherent PMNs in multicell aggregates. We constructed a novel plug flow interface between the flow cytometer and a cone-plate viscometer to enable real-time flow cytometric analysis of cell-cell adhesion under conditions of uniform shear. The High Throughput Pharmacology System (HTPS) is an instrument used for automated programming of complex pharmacological cell treatment protocols. It was interfaced via the plug flow coupling device to enable rapid (< 5 min) flow cytometric characterization of the intracellular calcium dose-response profile of U937 cells to formyl peptide. CONCLUSIONS: By facilitating the coupling of flow cytometers to other fluidics-based analytical instruments, plug flow cytometry has extended analytical capabilities in cell adhesion and pharmacological characterization of receptor-ligand interactions.

Animals↗

PubMed1994

Identification of patients at risk for inferior renal allograft outcome by a strongly positive B cell flow cytometry crossmatch.

To evaluate the influence of a positive B cell flow cytometry crossmatch (FCXM) on transplant outcome, we retrospectively performed B cell FCXMs for 431 consecutive cadaver renal transplant recipients using the two most current pretransplant sera. All transplant recipients had a negative lymphocytotoxic antiglobulin T cell XM and a negative (< or = 10 channel shift) T cell FCXM. B cell FCXMs were performed using a two-color technique to identify binding of IgG antibody to donor lymph node B lymphocytes stained for CD20. The incidence and causes of graft failure posttransplant were determined by requesting this information from recipient transplant centers. Transplants that failed due to nonimmunological causes (n = 54, 13%) were excluded from the analysis. Minimum follow-up was 12 months. We found no difference in graft survival at one year for transplants where the B cell FCXM was positive in the range of 11 to 50 channel shift (n = 201) compared with those with a negative (< or = 10 channel shift) B cell FCXM (n = 141)--i.e., 90% vs. 91%, P = NS. However, when the positivity in the B cell FCXM was > 50 channel shift (n = 35), significantly fewer grafts survived at one year, compared with those where the channel shift was < or = 50 (n = 342), 63% vs. 91%, P < 0.001. This was true for first transplants as well as regrafts and for transplants performed with a positive as well as a negative standard B cell XM. The detrimental effect of a positive B cell FCXM was seen for sensitized (PRA > 10% at the time of transplant) as well as nonsensitized patients. However, this effect was observed only when the donor had at least a one-DR mismatch. We conclude that a strongly positive B cell flow cytometry crossmatch identifies patients who are at risk for graft loss. Since the risk appears to be only when there is a DR mismatch, the data suggest that the B cell-specific IgG antibody detected by flow cytometry may be specific for the mismatched MHC class II antigens of the donor.

Antilymphocyte Serum↗

PubMed1994

Immunotyping of lymphoma by fine-needle aspiration. A comparative study of cytospin preparations and flow cytometry.

Immunotyping is an essential adjunct to cytomorphology for the diagnosis of lymphoma by fine-needle aspiration (FNA). Two independent techniques, cytospin preparations and flow cytometry, were used for immunotyping studies on 71 patients with histologically confirmed non-Hodgkin's lymphoma (63 B-cell lymphomas and 8 T-cell lymphomas). Diagnostic concordance between the two methods was obtained in 69 patients (97%). kappa, lambda, and CD3 (Leu-4) markers were routinely measured on all cytospins, and additional markers were requested when indicated. The standard panel measured by flow cytometry included 14 markers. In general, mean values of light-chain (kappa and lambda) immunoglobulins were consistently slightly higher by cytospin analysis than by flow cytometry. Light-chain immunoglobulin ratios (kappa/lambda or lambda/kappa) obtained by both methods proved to be reliable independent predictors of polyclonality or monoclonality. Correlation studies using the Spearman rank coefficient revealed good concordance among values of kappa, alpha, CD3, and CD5 obtained by the two techniques, suggesting that subjective quantitation by cytospins yields similar results to objective quantitation by flow cytometry. Cytospin analysis and flow cytometry appear equally capable of immunotyping aspirated lymphoid samples reliably. The advantages of each method are discussed.

Biopsy, Needle↗