scholarly journals Flow cytometric electronic direct current volume and radiofrequency impedance measurements of single cells and particles

Cytometry ◽  
1981 ◽  
Vol 1 (6) ◽  
pp. 377-384 ◽  
Author(s):  
R. A. Hoffman ◽  
T. S. Johnson ◽  
W. B. Britt
Keyword(s):  
Direct Current ◽  
Single Cells ◽  
Impedance Measurements ◽  
Flow Cytometric ◽  
Current Volume

scholarly journals Flow Cytometric Assessment of Susceptibilities of Streptococcus pyogenes to Erythromycin and Rokitamycin

2003 ◽  
Vol 47 (1) ◽  
pp. 408-412 ◽  
Author(s):  
Pier Carlo Braga ◽  
Cinzia Bovio ◽  
Maria Culici ◽  
Monica Dal Sasso
Keyword(s):  
Flow Cytometry ◽  
Fluorescence Microscopy ◽  
Streptococcus Pyogenes ◽  
Single Cells ◽  
Membered Ring ◽  
Flow Cytometric ◽  
Live Bacteria ◽  
Erythromycin A ◽  
Set Up ◽  
Syto 9

ABSTRACT The effects of erythromycin (a 14-membered ring macrolide) and rokitamycin (a 16-membered ring macrolide) on the viability of the Streptococcus pyogenes M phenotype were studied by means of flow cytometry and fluorescence microscopy by using a combination of two fluorochromes (syto 9 and propidium iodide) that stains live bacteria green and dead bacteria red. In order to apply the flow cytometry, a bacterial sonication procedure was expressly set up to separate single cells from the long, intralaced S. pyogenes chains of up to 30 to 40 cells that have previously prevented the application of flow cytometry to this type of bacteria. The association of flow cytometry using an appropriate sonication procedure, together with a combination of fluorescent probes, offered the possibility of very quickly investigating the different microbiological effects of rokitamycin at 2 μg/ml, which was active on the S. pyogenes M phenotype, and of erythromycin at doses of up to 32 μg/ml, which was not.

scholarly journals Chlorophyll fluorescence from single cells: Interpretation of flow cytometric signals

1989 ◽  
Vol 34 (8) ◽  
pp. 1749-1761 ◽  
Author(s):  
Heidi M. Sosik ◽  
Sallie W. Chisholm ◽  
Robert J. Olson
Keyword(s):  
Chlorophyll Fluorescence ◽  
Single Cells ◽  
Flow Cytometric

Comparison of Electrical Resistance and Impedance Measurements in Wood in Progressive Stages of Discoloration and Decay

1973 ◽  
Vol 3 (4) ◽  
pp. 593-595 ◽  
Author(s):  
Terry A. Tattar ◽  
George C. Saufley
Keyword(s):  
Direct Current ◽  
Electrical Resistance ◽  
Alternating Current ◽  
Pulsed Current ◽  
Impedance Measurements ◽  
Direct Current Resistance ◽  
Current Resistance

Direct current resistance and alternating current impedance were used to detect and quantify wood in progressive stages of discoloration and decay in living trees. Results were comparable to those obtained with pulsed current under similar conditions.

scholarly journals Assessment of the Potential of CDK2 Inhibitor NU6140 to Influence the Expression of Pluripotency Markers NANOG, OCT4, and SOX2 in 2102Ep and H9 Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Ade Kallas ◽  
Martin Pook ◽  
Annika Trei ◽  
Toivo Maimets
Keyword(s):  
Cell Cycle Progression ◽  
Single Cells ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Flow Cytometric Method ◽  
Histone 3 ◽  
Flow Cytometric ◽  
M Phase ◽  
Induced Apoptosis ◽  
Hes Cells

As cyclin-dependent kinases (CDKs) regulate cell cycle progression and RNA transcription, CDKs are attractive targets for creating cancer cell treatments. In this study we investigated the effects of the small molecular agent NU6140 (inhibits CDK2 and cyclin A interaction) on human embryonic stem (hES) cells and embryonal carcinoma-derived (hEC) cells via the expression of transcription factors responsible for pluripotency. A multiparameter flow cytometric method was used to follow changes in the expression of NANOG, OCT4, and SOX2 together in single cells. Both hES and hEC cells responded to NU6140 treatment by induced apoptosis and a decreased expression of NANOG, OCT4, and SOX2 in surviving cells. A higher sensitivity to NU6140 application in hES than hEC cells was detected. NU6140 treatment arrested hES and hEC cells in the G2 phase and inhibited entry into the M phase as evidenced by no significant increase in histone 3 phosphorylation. When embryoid bodies (EBs) formed from NU6104 treated hES cells were compared to EBs from untreated hES cells differences in ectodermal, endodermal, and mesodermal lineages were found. The results of this study highlight the importance of CDK2 activity in maintaining pluripotency of hES and hEC cells and in differentiation of hES cells.

scholarly journals Modern Trends in Imaging XI: Impedance Measurements in the Biomedical Sciences

2012 ◽  
Vol 35 (5-6) ◽  
pp. 363-374 ◽  
Author(s):  
Frederick D. Coffman ◽  
Stanley Cohen
Keyword(s):  
High Throughput Screening ◽  
Single Cells ◽  
Whole Body ◽  
Measuring Instruments ◽  
Biomedical Sciences ◽  
Impedance Measurements ◽  
Cell Monolayers ◽  
Disease States ◽  
Progression Of Disease ◽  
Biological Organisms

Biological organisms and their component organs, tissues and cells have unique electrical impedance properties. Impedance properties often change with changes in structure, composition, and metabolism, and can be indicative of the onset and progression of disease states. Over the past 100 years, instruments and analytical methods have been developed to measure the impedance properties of biological specimens and to utilize these measurements in both clinical and basic science settings. This chapter will review the applications of impedance measurements in the biomedical sciences, from whole body analysis to impedance measurements of single cells and cell monolayers, and how cellular impedance measuring instruments can now be used in high throughput screening applications.

A new monoclonal antibody to a cell-surface antigen that distinguishes luminal epithelial and myoepithelial cells in the rat mammary gland

1989 ◽  
Vol 94 (3) ◽  
pp. 545-552
Author(s):  
R.S. Mahendran ◽  
M.J. O'Hare ◽  
M.G. Ormerod ◽  
P.A. Edwards ◽  
R.A. McIlhinney ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Mammary Gland ◽  
Epithelial Cells ◽  
Milk Fat ◽  
Single Cells ◽  
Myoepithelial Cells ◽  
Stages Of Development ◽  
Leukaemia Cell Line ◽  
Flow Cytometric ◽  
Rat Mammary Gland

A monoclonal antibody (25.5) has been produced that recognises luminal epithelial cells of the rat mammary gland. This antibody together with monoclonal anti-CALLA antibodies, which react with mammary myoepithelial cells, has been used in biochemical, immunocytochemical and flow cytometric studies. Antibody 25.5 bound to proteins of molecular weight 70K and 25K (K = 10(3) Mr) in both the rat milk fat globule membrane and in single cell suspensions prepared from the virgin adult rat mammary gland. Anti-CALLA antibody (J5), recognised a 93–100K protein in the gland extracts, which co-electrophoresed with the CALLA/CD-10 antigen from NALM-6 acute lymphoblastic leukaemia cell line. Antibody 25.5 bound to the luminal surface of rat mammary epithelial cells at all stages of development from neonatal through to pregnancy, lactation and involution. CALLA immunoreactive staining has previously been shown on basally located presumptive myoepithelial cells at all stages of development. Flow cytometric analyses demonstrated that 25.5 and anti-CALLA antibodies stained independent cell populations in suspensions of single cells prepared from purified epithelial elements from the mammary gland of adult virgin rat.

Flow cytometric measurement of peptidases with use of 5-nitrosalicylaldehyde and 4-methoxy-beta-naphthylamine derivatives.

1977 ◽  
Vol 23 (8) ◽  
pp. 1485-1491 ◽  
Author(s):  
F A Dolbeare ◽  
R E Smith
Keyword(s):  
Aromatic Amine ◽  
Single Cells ◽  
Fluorescence Emission ◽  
Enzymatic Reactions ◽  
3T3 Cells ◽  
Clinical Value ◽  
Flow Cytometric ◽  
Flow Cytometric Measurement ◽  
Flow Microfluorometry ◽  
Kinetics Of

Abstract Enzyme activity can be measured in single cells or in cell suspensions by either static or flow microfluorometry when a fluorogenic substrate is used. We have used amino acid derivatives of arylamines as fluorogenic substrates for tagging cellular proteinases. The liberated aromatic amine, which can diffuse from the cell, is trapped as a fluorescent insoluble Schiff-base product with 5-nitrosalicylaldehyde, with the peak of fluorescence emission shifted from lambdaem 425 nm to lambdaem 530 and 595 nm. Although the reaction is faster at pH 4 than at higher pH's, the equilibrium during the assay of certain peptidase activities is such that the liberated aromatic amine is trapped in the cell at pH values as high as 7.5. 5-Nitrosalicylaldehyde causes almost no inhibition of substrate hydrolysis at 1 mmol/liter, a concentration exceeding that required for complete trapping of reaction product. The kinetics of enzymatic reactions with four synthetic substrates are demonstrated in intact Balb 3T3 cells and sonicated preparations in the presence of 5-nitrosalicylaldehyde. Hydrolytic rates for the substrate, CBZ-ala-arg-arg-4-methoxy-beta-naphthylamine, are given for single 3T3 cells by microfluorophotometry and for suspensions of 3T3 cells by flow cytometry. The clinical value of the method is demonstrated for differentiating mixed populations of leukocytes.

scholarly journals Detection of Bacteriophage-Infected Cells of Lactococcus lactis by Using Flow Cytometry

2007 ◽  
Vol 73 (23) ◽  
pp. 7575-7581 ◽  
Author(s):  
Ole Michelsen ◽  
Álvaro Cuesta-Dominguez ◽  
Bjarne Albrechtsen ◽  
Peter Ruhdal Jensen
Keyword(s):  
Lactococcus Lactis ◽  
Cell Walls ◽  
Single Cells ◽  
Low Density ◽  
Light Scatter ◽  
Infection Cycle ◽  
Bacteriophage Infection ◽  
Flow Cytometric ◽  
Infected Cells ◽  
Dairy Fermentation

ABSTRACT Bacteriophage infection in dairy fermentation constitutes a serious problem worldwide. We have studied bacteriophage infection in Lactococcus lactis by using the flow cytometer. The first effect of the infection of the bacterium is a change from cells in chains toward single cells. We interpret this change as a consequence of a cease in cell growth, while the ongoing cell divisions leave the cells as single cells. Late in the infection cycle, cells with low-density cell walls appear, and these cells can be detected on cytograms of light scatter versus, for instance, fluorescence of stained DNA. We describe a new method for detection of phage infection in Lactococcus lactis dairy cultures. The method is based on flow cytometric detection of cells with low-density cell walls. The method allows fast and early detection of phage-infected bacteria, independently of which phage has infected the culture. The method can be performed in real time and therefore increases the chance of successful intervention in the fermentation process.

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