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PubMedDate not supplied

Diagnosis of mediastinal masses in dogs by flow cytometry.

BACKGROUND: Biopsy of mediastinal masses can be invasive, but the procedure may be necessary if cytology of a mass aspirate is inconclusive. The 2 most common mediastinal masses, lymphoma and thymoma, may both be comprised of small lymphocytes. We investigated the ability of flow cytometry to distinguish between these 2 neoplasms. HYPOTHESIS: Flow cytometry of mediastinal mass aspirates may provide a definitive diagnosis of thymoma or lymphoma, reducing the need for biopsy. ANIMALS: Dogs with mediastinal masses presenting to the Veterinary Teaching Hospital/Animal Cancer Center were included in the study. METHODS: Aspirates obtained over 2 years that met the inclusion criteria (i.e. sufficient viable cells and a definitive diagnosis by means other than flow cytometry) were analyzed by flow cytometry to determine the percentage of cells expressing B- and T-cell markers, and co-expressing CD4 and CD8. RESULTS: All cases of thymoma (n = 6) consisted of > or = 10% lymphocytes coexpressing CD4 and CD8, a phenotype that is characteristic of thymocytes, whereas 6 of 7 lymphomas contained <2% CD4+CD8+ lymphocytes. The CD4+CD8+ lymphoma could be readily distinguished flow cytometrically from thymoma by light scatter properties. The phenotypes of the remaining lymphomas were CD4+ T cell (4), CD34+ (1) and B cell (1). CONCLUSIONS: Our studies demonstrate that flow cytometry is a useful tool for discriminating mediastinal masses. Lymphocyte-rich mediastinal masses could be unambiguously identified by flow cytometry in 13/13 cases.

Animals↗
PubMed1986

Flow cytometry of renal oncocytoma: common occurrence of deoxyribonucleic acid polyploidy and aneuploidy.

Flow cytometry was performed on 51 typical specimens of renal oncocytoma. Nuclei were extracted from paraffin-embedded archival material and isolated nuclei were stained with propidium iodide. Of the 51 available tissue blocks 86 per cent were evaluable and 50 per cent of these samples showed a deoxyribonucleic acid (DNA) histogram that was approximately the same as normal renal parenchyma. Of the oncocytoma samples 39 per cent showed a marked increase (more than 10 per cent of the nuclei) in the tetraploid DNA peak, while 11 per cent showed a distinct DNA aneuploid peak. Among 21 evaluable grade 2 oncocytic renal tumors 33 per cent showed a normal DNA histogram, 43 per cent showed a marked increase in the DNA tetraploid peak and 24 per cent showed a DNA aneuploid peak. The common presence of polyploid nuclei containing double quantities of chromosomal DNA may correlate with the long-standing pathological observation that oncocytic tumors often contain a distinct population of large nuclei. Indeed, 86 per cent concurrence was seen between the detection of an abnormal DNA content by flow cytometry and the histopathological presence of large abnormal nuclei in these specimens. Since renal oncocytomas (grade 1 oncocytic tumors) rarely, if ever, metastasize and are relatively noninvasive locally, their markedly abnormal flow cytometry patterns are of considerable interest. Moreover, DNA polyploidy has not been identified previously in renal tumors. The biological significance and mechanism of DNA polyploidy, and the relationship of DNA polyploidy and DNA aneuploidy to the pathogenesis of oncocytic renal tumors require further laboratory investigation. The clinical use of flow cytometry to classify and to predict the behavior of renal tumors will be complicated, since renal oncocytomas commonly have polyploid and aneuploid DNA histograms.

Adenoma↗
PubMed1984

The biology of tumor growth in the non-Hodgkin's lymphomas. A dual parameter flow cytometry study of 220 cases.

Dual parameter flow cytometry studies (cell DNA content and electronic cell volume) were performed in 220 cases of non-Hodgkin's lymphoma. All cases were characterized as B or T cell malignancies, based on immunologic surface marker characteristics. Aneuploidy by flow cytometry was more common among the B cell lymphomas than among the T cell lymphomas, and was most common among the large B cell lymphomas and B cell lymphomas of intermediate size. Ploidy index distributions showed a prominent hyperdiploid peak, as well as tumor cell populations with near-tetraploid DNA contents. In serial studies, a decrease in ploidy index was observed in association with clinical and histologic transformation in one case. The highest S fractions were observed among the large and intermediate B cell lymphomas and among the aggressive T cell lymphomas. In clinical samples consisting of mixtures of diploid and aneuploid populations, the data on the aneuploid components could often be separated from other components of the mixture in multiparameter studies on the basis of the larger electronic cell volumes of the aneuploid cells. In each case, the aneuploid large cell component almost invariably had a higher S fraction than the residual component(s) of the mixture. Overall, the data are consistent with a model of clonal selection and clonal evolution in the lymphomas in which early cytogenetic abnormalities that involve little or no change in total cell DNA content are followed by cell tetraploidization that is associated with cytogenetic instability and chromosome loss over the course of time.

Aneuploidy↗
PubMed1987

Flow cytometry and Feulgen cytophotometry in evaluation of effusions.

Fifty-eight effusions (42 pleural and 16 ascitic fluids) from patients with and without cancer were analyzed by conventional cytology and the results compared with DNA patterns generated by flow cytometry of 10(4) nuclei and several modes of Feulgen cytophotometry. In 31 patients (24 without evidence of cancer and seven with history of cancer and cytologically negative fluids), the fluids were diploid by flow cytometry. One fluid with atypical cells from a lymphoma suspect was also diploid. Flow cytometry of 26 cytologically cancerous fluids disclosed aneuploid DNA patterns in 16 and diploid patterns in ten. Feulgen cytophotometry of 11 of these fluids (three aneuploid, eight diploid) was performed on nuclear preparations identical to those used in flow cytometry and on restrained smears used for visual analysis. The analysis was performed in two modes: as a study of 500 sequential nuclei in an automated system, mimicking flow cytometry, and visually selected large, presumably malignant nuclei. In nine of the 11 cases, the DNA content of visually selected cancer cells was aneuploid, even though this DNA pattern was not evident in the analysis of 500 sequential cells. In two cases, both diploid by flow cytometry, the Feulgen analysis confirmed the presence of cancer cells in the diploid range. In samples of 10(4) nuclei representing a mixed population of cells occurring in effusions, the presence of aneuploid cancer cells may not be disclosed by conventional flow cytometry. A larger sample of cells, a detailed analysis of DNA histograms, and perhaps sorting of select cells in the hypertetraploid range, may prove essential before flow cytometry can be accepted as a diagnostic tool in the laboratory in the assessment of effusions.

Aneuploidy↗
PubMed1978

Flow cytometry in tumours of the brain.

Flow cytometry was used for studying the distribution of single cell DNA content in biopsy material from 85 patients with benign and malignant lesions of the brain and spinal cord. In inflammatory lesions and in most benign tumours, cells with diploid DNA values were observed, sometimes with additional smaller amounts of tetraploid DNA. Cells from malignant tumours were characterized by marked hyperploid DNA values. Flow cytometry is found a rapid and valuable method adding important information to the biological nature of tumours of the central nervous system.

Biopsy↗
PubMed1987

Flow cytometry and its applications in veterinary medicine.

Flow cytometry is a technique for analysing and separating populations of cells (and subcellular components). The cells are generally stained with fluorescent markers (eg, fluorescent antibodies or DNA-binding dyes). Each cell is analysed individually, at high speed. Thus, assays may be performed on small samples (less than 10,000 cells). A subpopulation of interest can be separated from the remainder of the cells to a high degree of purity (up to 99 per cent). The application of flow cytometry to veterinary science is increasing and is discussed here.

Animals↗
PubMed1994

Flow cytometry in the diagnosis of brain tumors.

Flow cytometry is a useful technique for detecting surface antigens on cells in suspension, particularly lymphoid cells in blood or disaggregated lymphoid tissue. It is eminently suited to the diagnosis of lymphoma, but its use in differentiating brain tumors depends on better definition of tumor cell surface antigens. Flow cytometry's best application is in measuring cellular DNA content and proliferative activity of tumor cells, and, therefore, it can readily detect whether a tumor is diploid or aneuploid. Clinical correlations of aneuploidy in astrocytomas are still controversial, but there is significant evidence relating aneuploidy to a favorable prognosis in patients with neuroblastoma and medulloblastoma. Studies in which the proliferation fraction was assessed by means of BUdR incorporation or using the monoclonal antibody Ki-67 indicate a marked correlation with biological behavior in a variety of brain tumors.

Antigens, Neoplasm↗
PubMed2003

Cytokine flow cytometry: multiparametric approach to immune function analysis.

More precise quantitation of cellular immune responses has become possible with the advent of single-cell assays of immune function, such as cytokine flow cytometry, enzyme-linked immunospot (ELISPOT), and MHC-peptide multimers. Cytokine flow cytometry is an attractive technique because it allows the detection of responses to whole antigens without regard to MHC restriction, while also collecting additional information on responding cells via multiparameter flow cytometry. In this review, we compare cytokine flow cytometry with other assays of immune function, summarize some of that data that have been collected in various disease states using cytokine flow cytometry, and describe some methodological improvements designed to increase the robustness, throughput, and information content of this technique. We hypothesize that a new generation of automated cytokine flow cytometry assays will allow elucidation of the correlates of protection for diseases involving cellular immunity, through application of these assays in more and large clinical trials.

Cytomegalovirus Infections↗
PubMed2001

Cryptomonad algal phycobiliproteins as fluorochromes for extracellular and intracellular antigen detection by flow cytometry.

BACKGROUND: Phycobiliproteins play an important role in fluorescent labeling, particularly for flow cytometry. The spectral properties of R-phycoerythrin (R-PE) and allophycocyanin (APC) have made them the dominant reagents in this class of fluorochromes. In this study, we evaluate a lesser-known but potentially important series of low-molecular weight cryptomonad-derived phycobiliproteins (commercially termed the CryptoFluortrade mark dyes) for their applicability to flow cytometry, both in extracellular and intracellular labeling applications. METHODS: Several cell lines were labeled with biotin-conjugated antibodies against expressed extracellular surface proteins, followed by streptavidin conjugates of three cryptomonad phycobiliproteins (CryptoFluor-2, CryptoFluor-4, and CryptoFluor-5). Cells were then analyzed by flow cytometry using a variety of laser lines and emission filters to establish the optimal excitation/emission characteristics for each fluorochrome. Some cells were permeabilized and labeled for intracellular antigens, also using the cryptomonad fluorochromes. Where appropriate, parallel samples were labeled with other fluorochromes (including R-PE, APC, the cyanin dyes Cy3 and Cy5, and others) to gauge the performance of the cryptomonad fluorochromes against fluorescent labels previously evaluated for flow cytometry. RESULTS: CryptoFluor-2 possessed excitation/emission maxima similar to those of APC and Cy5, with good excitation in the red (HeNe laser 632 nm) and strong emission in the far red (660 nm). CryptoFluor-4 possessed excitation/emission maxima similar to those of Cy3, with optimal excitation in the green (Kr 530 nm) and strong emission in the yellow/orange (585 nm). CryptoFluor-5 possessed excitation/emission maxima similar to those of lissamine rhodamine, with optimal excitation in the yellow (Kr 568 nm) and emission in the orange (610 nm). All cryptomonad fluorochromes gave satisfactory results for both intracellular and extracellular labeling, with detection sensitivities that were comparable or better than traditional phycobiliproteins and low- molecular weight synthetic fluorochromes such as the cyanin dyes. CONCLUSIONS: The CryptoFluor fluorochromes were applicable to flow cytometric immunodetection, with excitation and emission conditions commonly found on multilaser instruments. Performance of several of these dyes was at least comparable to existing fluorescent labels. The low molecular weights (30-60 kd) of phycobiliproteins may make them particularly useful in intracellular antigen detection. Cytometry 44:16-23, 2001. Published 2001 Wiley-Liss, Inc.

Algal Proteins↗
PubMed1988

Relative prognostic significance of DNA flow cytometry and histologic grading in endometrial carcinoma.

Flow cytometric analyses of the DNA content of neoplastic cells were performed in 60 cases of endometrial carcinoma using formalin-fixed, paraffin-embedded tissues. Each tumor was graded histologically prior to flow cytometry. Aneuploidy was found in almost half of the tumors, including those of moderate and high degrees of differentiation, although the poorly differentiated tumors were more commonly aneuploid. The cytometric and histologic results were then compared with prognosis (5-year survival). In general, survival was greater with diploid than with aneuploid tumors. With well-differentiated tumors, patients with both diploid and aneuploid lesions had a favorable prognosis, but with moderately and poorly differentiated tumors those with diploidy had a more favorable prognosis than those with aneuploidy. We conclude that flow cytometry is of principal prognostic value in poorly differentiated endometrial carcinomas.

Adenocarcinoma↗
PubMed1988

A new microsphere-based immunofluorescence assay using flow cytometry.

The quantitative and qualitative capacities of flow cytometric analysis that have made it such a powerful tool in studies of cellular antigens have not previously been exploited when dealing with non-cellular antigens. A new immunofluorescence assay technique was developed, using an indirect staining procedure with monoclonal anti-kappa antibodies, to detect human free kappa light chains covalently bound to microspheres of a size suitable for flow cytometry. The strength of the fluorescent signal produced on the microspheres was related to the amount of antigen bound and the size of the beads. At the time of this work large microspheres (i.e., greater than 3 micron in diameter) suitable for this application were only available as suspensions of polysized beads. The fluorescent signal detected on labelled beads was optimized by selecting for analysis, on the basis of the forward angle laser scatter, only those beads of largest diameter. There are many potential applications for this technique - microspheres can be used for the presentation of virtually any antigen or antibody. The analytical benefits inherent in flow cytometry would be a significant advantage in the development of quantitative assays using this method.

Antibodies, Monoclonal↗
PubMed1997

Diagnosis and carrier detection of chronic granulomatous disease in five families by flow cytometry.

BACKGROUND: The application of flow cytometric assays, for determination of phagocyte respiratory burst (ROB) activity, to the investigation of chronic granulomatous disease (CGD) may lead to improved laboratory detection of patients and carriers and indicate the nature of the molecular defect. To evaluate the diagnostic capability of flow cytometry an investigation of 5 CGD families was undertaken. METHODS: Phorbol myristate acetate (PMA)-induced neutrophil ROB was determined using dihydrorhodamine 123 (DHR) and flow cytometric analysis in 26 members of 5 CGD families (2: X-CGD; 3: autosomal recessive CGD). RESULTS: Neutrophils from X-CGD patients displayed absence of reactivity. Female carriers demonstrated dual fluorescence peaks of high and low intensity indicative of normal and abnormal populations, respectively. Normal ROB activity was observed in a boy whose X-CGD was successfully treated by bone marrow transplantion. Reduced ROB activity was observed in 3 patients with autosomal-recessive CGD compared with their parents and siblings. The patterns of flow cytometric reactivity correlated with the different molecular defects identified. Absence of the p22phox membrane component of the NADPH oxidase complex resulted in a significantly reduced level of respiratory burst activity which was comparable to that observed in X-CGD, whereas reduced but detectable levels of respiratory burst activity were observed in a patient with diminished levels of p22phox and in a patient with deficiency of the cytosolic p47phox component. CONCLUSIONS: The DHR flow cytometric assay offers a sensitive diagnostic screening test for CGD and furthermore may provide an indication of the likely underlying molecular defect.

Adolescent↗
PubMed2006

Simultaneous detection of porcine proinflammatory cytokines using multiplex flow cytometry by the xMAP technology.

BACKGROUND: Multiplex flow cytometry is in widespread use for detection of cytokines in human samples. However, no report on the measurement of porcine cytokines using this method has previously been published. We report on the detection of the porcine proinflammatory cytokines TNF-alpha, IL-8, and IL-1beta by the xMap-assay for multiplex flow cytometry. METHODS: Commercially available antibodies to porcine cytokines were used as capture antibodies by attaching them to goat anti-mouse IgG coated microspheres with different fluorescent signatures. By the use of biotinylated detection antibodies and SAv-PE the amount of cytokines bound to the spheres were measured. Experiments were performed to determine the limits of detection and the amount of crossreactivity in buffer, serum, and plasma, using spiking with recombinant porcine cytokines. RESULTS: The limit of detection ranged from 0.18 to 12 ng/ml. Generally, the detection limit was higher in serum and plasma, than in buffer. No crossreactivity between reagents was found. CONCLUSIONS: Porcine proinflammatory cytokines can be detected utilizing this method with satisfactory detection limits, and no crossreaction between the reagents involved.

Animals↗
PubMed1990

Intracellular pH, esterase activity, and DNA measurements of human lung carcinomas by flow cytometry.

An important intention of flow cytometric investigations is to obtain biochemical and biophysical information about cells which is suitable for automated tumor diagnosis. In this study, the ploidy status, the intracellular pH value, the intracellular esterase activity, and the cell volume of vital cells and the DNA and cell volume of dead cells were measured in cancerous tissue and normal lung tissue of 30 patients by flow cytometry. The cell samples were simultaneously stained with the pH and esterase indicator dye 1.4-diacetoxy-2,3-dicyanobenzene (ADB) and propidium iodide (PI). The flow cytometric measurements were performed in three-parameter list mode. The data were evaluated on an AT-compatible personal computer with the DIAGNOS1 program system for automated diagnosis of flow cytometric list mode data. Significant differences were found between normal and malignant tissue in DNA ploidy, in the intracellular esterase activity, in the cell, volume and in the percentage of inflammatory cells and parameters of necrosis. DNA-aneuploidy was observed in 38% of the lung carcinomas. The simultaneous detection of DNA-aneuploidy and tumor-associated properties in a multifactorial analysis led to correct automatic tumor diagnosis in 85% of cases. DNA-aneuploidy was found at a significant higher frequency in advanced tumors. Adenocarcinomas displayed DNA-aneuploidy more often (80%) than squamous cell carcinomas (33%).

Adenocarcinoma↗
PubMed1991

Coincidence in high-speed flow cytometry: models and measurements.

In flow cytometry, the coincident arrival of particles becomes a major problem when high sample rates are required. For the development of our high-speed photodamage flow cytometer (ZAPPER), it was of importance to understand the behavior of cells at flow rates of around 50,000-250,000 event/s. We developed and compared two models that describe the relation between the real cell rate and the detectable single cell rate. Both the Computer Simulation model and the Input/Output Device model show distinct optima for the cell rate. The models were compared to measurements performed on the ZAPPER-prototype. Fits of the two models to the experimental data were excellent for cycle times of 4 and 15 microseconds and acceptable for a 2 microseconds cycle time. A third model (Mercer WB, Rev. Sci. Instr. 37:1515-1521,1966) could be fitted to the experimental data, after the proportionality constant k was adapted to the experimental data. At a yield of detectable single cells of 70%, the maximum cell rates are 180,000, 100,000, and 40,000 cells/s for cycle times of 2, 4, and 15 microseconds, respectively. Based on these results we can now select an optimal cell rate for analysis and sorting based on criteria such as accepted cell loss. In addition, the advantages of reducing the cycle time can now be evaluated with respect to the costs of that modification.

Cell Separation↗
PubMedDate not supplied

[The prognostic value of flow cytometry in prostatic cancer].

DNA quantitation by flow cytometry was made in 36 patients with morphologically diagnosed prostatic cancer (PC) in stage II, III and IV (4, 14 and 18 patients, respectively). All the patients received adequate treatment. Aneuploid tumours were found in 25 patients (group 1), diploid ones in 11 patients (group 2). A 3-year survival in group 1 made up 65.5%, in group 2 all the patients survived 3 years. The recurrence-free survival was 22.2% and 78.8%, respectively. The above findings make it possible to regard flow cytometry DNA estimation as a reliable prognostic indication in PC.

Adult↗
PubMed1995

Spatial dependence of the optical collection efficiency in flow cytometry.

The sensitive flow cytometric detection of fluorescent species in liquid sample streams requires efficient collection of light from small [approximately 1 picoliter (pl)] sample volumes. This is often accomplished with high numerical aperture (NA) imaging collection optics used in combination with a spatial filter. A method to measure the spatial variation of the optical collection efficiency within the sample volume, using a submicrometer light source, is described. Measurements of the relative optical collection efficiency are presented for two optical collection systems used in our laboratory for single molecule detection. The measurement are in qualitative agreement with relative optical collection efficiency calculations using a simple geometrical optics model. Absolute measurements of the peak collection efficiencies for the two collection systems are also presented. These absolute collection efficiency measurements are in good quantitative agreement with ideal collection efficiencies calculated using measured transmissions and rated NAs of the collection optics. The utility of this information for the characterization and optimization of sensitive fluorescence detection apparatus is discussed.

Equipment Design↗