scholarly journals Flow cytometric analysis of the inhibition of human basophil activation by histamine high dilutions - a replication study

2021 ◽  
Vol 11 (40) ◽  
pp. 172-173
Author(s):  
Chantal Wälchli ◽  
Stephan Baumgartner
Keyword(s):  
Flow Cytometry ◽  
Flow Cytometric Analysis ◽  
Systematic Errors ◽  
Basophil Activation ◽  
Human Basophil ◽  
Specific Marker ◽  
Flow Cytometric ◽  
High Dilutions ◽  
Independent Replication ◽  
Human Basophils

Background: Inhibition of human basophil activation by highly diluted histamine was reported to be a reliable experimental model to examine biological effects of high dilutions. However, independent replications did not always yield concordant results. Aims: We aimed at performing an independent replication of a former study [1] using rigorously controlled experimental conditions to minimise confounding factors. Materials and Methods: In 20 independent experiments, human basophils were treated with highly diluted histamine (15cH, 16cH, corresponding to 10-30-10-32 M) prior to activation by fMLP (formyl-methionyl-leucyl-phenylalanine peptide). Controls were treated with analogously diluted water (15cH, 16cH). The dilutions were prepared freshly for each experiment in deionised water by successive steps of centesimal dilution and agitation (10 s vortex at high speed). Highly diluted samples were blinded and randomised. All samples were set in triplicates. Activated basophils were determined by flow cytometry using anti-CD203c. 20 independent systematic negative control (SNC) experiments were carried out to investigate possible systematic errors. Results: No difference in basophil activation was observed between the highly diluted histamine samples and the highly diluted water controls. There was no evidence for a blood donor specificity of the results. The SNC experiments demonstrated the stability of the test system. Experimental variability within and between experiments was slightly reduced for the highly diluted histamine samples. Discussion: This study was designed as an independent reproduction of a former study [1]. Though we strictly adopted the experimental procedure described in [1], our results do not confirm the large inhibitory effects observed for histamine 15cH and 16cH. This lack of reproducibility might be due to minor differences in the experimental design, such as blinding and randomising of the samples, which we chose to perform in order to reduce the possibility of artifacts but was omitted in the former study. Conclusions: Laboratory independent replication of homeopathic basic research experiments is still a challenge. Assuming that the results formerly obtained with this model were not due to systematic errors, the quest identifying the crucial factors for successful reproducibility is open for future research. Keywords: Human basophils; histamine; high dilutions; flow cytometry Reference: [1] Sainte-Laudy J, Belon P. Improvement of flow cytometric analysis of basophil activation inhibition by high histamine dilutions. A novel basophil specific marker: CD 203c. Homeopathy. 2006;95:3-8.

scholarly journals Multiparameter Flow Cytometric Analysis of Antibiotic Effects on Membrane Potential, Membrane Permeability, and Bacterial Counts of Staphylococcus aureus andMicrococcus luteus

2000 ◽  
Vol 44 (4) ◽  
pp. 827-834 ◽  
Author(s):  
David J. Novo ◽  
Nancy G. Perlmutter ◽  
Richard H. Hunt ◽  
Howard M. Shapiro
Keyword(s):  
Staphylococcus Aureus ◽  
Flow Cytometry ◽  
Membrane Potential ◽  
Membrane Permeability ◽  
Micrococcus Luteus ◽  
Flow Cytometric Analysis ◽  
Bacterial Counts ◽  
Flow Cytometric ◽  
Permeability Parameter ◽  
Particle Counts

ABSTRACT Although flow cytometry has been used to study antibiotic effects on bacterial membrane potential (MP) and membrane permeability, flow cytometric results are not always well correlated to changes in bacterial counts. Using new, precise techniques, we simultaneously measured MP, membrane permeability, and particle counts of antibiotic-treated and untreated Staphylococcus aureus andMicrococcus luteus cells. MP was calculated from the ratio of red and green fluorescence of diethyloxacarbocyanine [DiOC2(3)]. A normalized permeability parameter was calculated from the ratio of far red fluorescence of the nucleic acid dye TO-PRO-3 and green DiOC2(3) fluorescence. Bacterial counts were calculated by the addition of polystyrene beads to the sample at a known concentration. Amoxicillin increased permeability within 45 min. At concentrations of <1 μg/ml, some organisms showed increased permeability but normal MP; this population disappeared after 4 h, while bacterial counts increased. At amoxicillin concentrations above 1 μg/ml, MP decreased irreversibly and the particle counts did not increase. Tetracycline and erythromycin caused smaller, dose- and time-dependent decreases in MP. Tetracycline concentrations of <1 μg/ml did not change permeability, while a tetracycline concentration of 4 μg/ml permeabilized 50% of the bacteria; 4 μg of erythromycin per ml permeabilized 20% of the bacteria. Streptomycin decreased MP substantially, with no effect on permeability; chloramphenicol did not change either permeability or MP. Erythromycin pretreatment of bacteria prevented streptomycin and amoxicillin effects. Flow cytometry provides a sensitive means of monitoring the dynamic cellular events that occur in bacteria exposed to antibacterial agents; however, it is probably simplistic to expect that changes in a single cellular parameter will suffice to determine the sensitivities of all species to all drugs.

scholarly journals Chromosome doubling in Cattleya tigrina A. Rich

2019 ◽  
Vol 15 (11) ◽  
Author(s):  
Thays Saynara Alves Menezes-Sá ◽  
Maria de Fátima Arrigoni-Blank ◽  
Andréa Santos da Costa ◽  
Janay De Almeida Santos-Serejo ◽  
Arie Fitzgerald Blank ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Propidium Iodide ◽  
Chromosome Doubling ◽  
Flow Cytometric Analysis ◽  
Leaf Tissue ◽  
Stomatal Index ◽  
Chromosome Duplication ◽  
Flow Cytometric ◽  
Young Leaves ◽  
Commercial Value

Chromosome doubling induction in orchids may benefit their production for resulting in flowers of higher commercial value, larger size and higher content of substances that intensify the color and fragrance when compared with diploid orchids. This work aimed to induce and confirm artificial polyploidization, using flow cytometry and stomatal analysis. Explants were treated with colchicine at concentrations of 0, 2.5, 7.5, and 12.5 mM, for 24 and 48 hours and with oryzalin, at concentrations of 0, 10, 30, and 50 μM, for three and six days. For the flow cytometric analysis, a sample of leaf tissue was removed from each plant, crushed to release the nuclei and stained with propidium iodide. In addition to flow cytometry, the ploidy of the antimitotic treated plants was evaluated by stomata analysis. Young leaves were used where the density, functionality and stomatal index were evaluated. Colchicine provided induction of satisfactory polyploidy in C. tigrina at all concentrations and times of exposure, obtaining a greater number of polyploid individuals in the concentration of 12.5 mM for 48 hours. Oryzalin did not induce chromosome duplication at the tested concentrations.

scholarly journals Flow cytometric analysis of herpes simplex virus type 1 susceptibility to acyclovir, ganciclovir, and foscarnet.

1997 ◽  
Vol 41 (12) ◽  
pp. 2686-2692 ◽  
Author(s):  
I Pavić ◽  
A Hartmann ◽  
A Zimmermann ◽  
D Michel ◽  
W Hampl ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Cytopathic Effect ◽  
Flow Cytometric Analysis ◽  
Flow Cytometric ◽  
Resistant Strains ◽  
Simplex Virus

We established a quantitative flow cytometric method for determination of herpes simplex virus type 1 (HSV-1) susceptibility to acyclovir (ACV), ganciclovir, and foscarnet in vitro. Susceptibility was defined in terms of the drug concentration which reduced the number of cells expressing HSV-1 glycoprotein C (gpC) with a fluorescence intensity of > or =10(2) by 50% (IC50). Flow cytometry allowed us to use a high (1.0) as well as a low (0.005) multiplicity of infection, and determination of the IC50 was possible after one or more viral replicative cycles. IC50s were dependent on virus input and on time postinfection. In mixture experiments, 1 to 2% resistant viruses added to a sensitive strain could be detected. The results obtained by flow cytometry showed a good qualitative correlation with those achieved by cytopathic effect inhibitory assay. However, flow cytometry might detect more quantitative differences in drug susceptibility, especially among resistant strains, as confirmed also by determination of intracellular drug phosphorylation. The mean IC50s for ACV-sensitive strains were 0.45 to 1.47 microM, and those for ACV-resistant strains were between 140 and 3,134 microM. Flow cytometric analysis was fast and accurate, automatizable, and highly reproducible. Flow cytometry may be a more powerful tool than standard cytopathic effect-based assays and could have advantages for the detection of low levels of drug resistance or mixtures of sensitive and resistant virus strains.

scholarly journals Flow cytometric analysis of virus-like particles and heterotrophic bacteria within coral-associated reef water

2006 ◽  
Vol 86 (3) ◽  
pp. 563-566 ◽  
Author(s):  
Nicole L. Patten ◽  
Justin R. Seymour ◽  
James G. Mitchell
Keyword(s):  
Flow Cytometry ◽  
Bacterial Community ◽  
Heterotrophic Bacteria ◽  
Flow Cytometric Analysis ◽  
Water Layer ◽  
Dead Coral ◽  
Overlying Water ◽  
Virus Like Particles ◽  
Flow Cytometric ◽  
Diseased Coral

Using flow cytometry, two distinct populations of virus-like particles (VLP) and heterotrophic bacteria were defined within the 12 cm water layer immediately overlying healthy, diseased and dead acroporid corals. Bacterial abundances were similar in overlying water for all coral types, however, VLP were 30% higher above diseased corals than healthy or dead corals. Mean virus to bacteria ratios (VBR) were up to 30% higher above diseased corals than above healthy or dead coral or in distant water. Concomitant with increasing VLP concentrations within 5 cm of coral surfaces, VBR distributions were generally highest above healthy and diseased coral and depressed above dead coral. These results suggest fundamental shifts in the VLP and bacterial community in water associated with diseased corals.

scholarly journals Ethanol fixation of bladder irrigation specimens for flow cytometric analysis. A multiinstitutional study from the bladder cancer flow cytometry network

Cancer ◽  
1990 ◽  
Vol 63 (9) ◽  
pp. 1780-1783 ◽  
Author(s):  
Dane K. Hermansen ◽  
Myron R. Melamed ◽  
John S. Coon ◽  
Ronald S. Weinstein ◽  
Ralph Devere White ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Bladder Cancer ◽  
Flow Cytometric Analysis ◽  
Bladder Irrigation ◽  
Flow Cytometric

scholarly journals Application of Digital Image Analysis and Flow Cytometry To Enumerate Marine Viruses Stained with SYBR Gold

2001 ◽  
Vol 67 (2) ◽  
pp. 539-545 ◽  
Author(s):  
Feng Chen ◽  
Jing-rang Lu ◽  
Brian J. Binder ◽  
Ying-chun Liu ◽  
Robert E. Hodson
Keyword(s):  
Flow Cytometry ◽  
Image Analysis ◽  
Digital Image ◽  
Digital Image Analysis ◽  
Flow Cytometric Analysis ◽  
Epifluorescence Microscopy ◽  
Flow Cytometric ◽  
Viral Particles ◽  
Sybr Gold ◽  
Nucleic Acid Stain

ABSTRACT A novel nucleic acid stain, SYBR Gold, was used to stain marine viral particles in various types of samples. Viral particles stained with SYBR Gold yielded bright and stable fluorescent signals that could be detected by a cooled charge-coupled device camera or by flow cytometry. The fluorescent signal strength of SYBR Gold-stained viruses was about twice that of SYBR Green I-stained viruses. Digital images of SYBR Gold-stained viral particles were processed to enumerate the concentration of viral particles by using digital image analysis software. Estimates of viral concentration based on digitized images were 1.3 times higher than those based on direct counting by epifluorescence microscopy. Direct epifluorescence counts of SYBR Gold-stained viral particles were in turn about 1.34 times higher than those estimated by the transmission electron microscope method. Bacteriophage lysates stained with SYBR Gold formed a distinct population in flow cytometric signatures. Flow cytometric analysis revealed at least four viral subpopulations for a Lake Erie sample and two subpopulations for a Georgia coastal sample. Flow cytometry-based viral counts for various types of samples averaged 1.1 times higher than direct epifluorescence microscopic counts. The potential application of digital image analysis and flow cytometry for rapid and accurate measurement of viral abundance in aquatic environments is discussed.

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