Friday 30 May 2014

Dead cell exclusion - in a "virtual" flow cytometry channel

DRAQ7-labeled dead cells can be excluded without any need for a separate channel or compensation!

HOW? 
DRAQ7 can be excited across the visible spectrum, from blue to red.
No other chromophore we have checked behaves like this.  And, it's easy:
  • Split a sample. Stain half with antibody panel alone and half with antibody panel + DRAQ7  
  • Analyse each on a flow cytometer with at least two lasers (from blue to red)
  • Plot all the red and far-red channels against each other
  • Choose a bi-exponential plot with clearly separated double-positive events (in +DRAQ7 tube)
  • These are the DRAQ7+ dead cells - draw a gate to exclude them
  • You've now set up your virtual channel for dead cells with this panel!
RESULT:
The dead cells disappear from all channels, requiring no compensation or adjustment of voltages, panel splitting or transfer to a more complex instrument.  Just imagine, now you can take an existing panel and add the viability dye DRAQ7! You can even make a 6 channel instrument accept 7 colours!

Depending on your flow cytometer's laser and detection channel choices you can easily set up a panel that works like this with blue, green, yellow, orange, or red lasers!  All you need is two of these lasers and you are away!

Get a copy of our application note or the poster (Abstr. 144) from CYTO 2014 via the contact page

Another reason why DRAQ7 is THE viability dye of choice!     #DRAQ7

Thursday 29 May 2014

No-lysis flow cytometric analysis of dyserythropoiesis

A recent Leukemia paper by clinical scientists in Paris (Mathis, et al. demonstrates use of CyTRAK Orange to allow lysis-free analysis of whole bone marrows.  

This CyTRAK Orange-dependent “live" or nucleated cell gate was combined with BV421, FITC, PC-7, APC and APC-AF700 coupled antibodies on a Beckman Coulter Navios. Forward & side scatter parameters are preserved in the presence of CyTRAK Orange.  

Usefully, CyTRAK Orange is not excited by violet or red laser lines with no overlap with FITC allowing for multi-colour panels whilst avoiding time-consuming lysis procedures and resulting uncontrolled cell losses.

"..the aim of this study was to identify markers of dyserythropoiesis relevant for the diagnosis of MDS analyzed by selecting erythroblasts in a whole no-lysis bone marrow strategy by using a nuclear dye."  The authors show statistical significance of key erythroblast markers CD36 and CD71 between MDS patient and control samples that they state should improve the classification of patients.

WHERE TO BUY

Reference:

Flow cytometric detection of dyserythropoiesis: a sensitive and powerful diagnostic tool for myelodysplastic syndromes

S Mathis, N Chapuis, C Debord, A Rouquette, I Radford-Weiss, S Park, F Dreyfus, C Lacombe, M C Béné, O Kosmider, M Fontenay and V Bardet.

Improved MK quantitation in bone marrow

The far-red, live-cell permeant DNA dye DRAQ5 has been combined with thrombocyte and lineage markers for analysis by Amnis Imagestream imaging flow cytometry to study megakaryocytes (MK) in bone marrow.  

This approach improved quantitation of MK, further extended by polyploidy distributions and a direct indication of MK cell exhaustion, which appeared to be linked to the highest polyploidies.  

Using DRAQ5 this was all possible without any cell fixation, avoiding unnecessary sample preparation steps! 


See Niswander, et al. Cytometry Part A (2014) 85.4: 302-312.

Tuesday 27 May 2014

3rd RNAi and Functional Genomics Screening Meeting

3rd RNAi and Functional Genomics Screening Meeting:
Date: June 9, 2014
Place: SOAS, UCL, London, UK

BioStatus is delighted to be a sponsor of this meeting and will exhibit

BioStatus supplies the ideal DNA counterstains and viability dyes for RNAi knockdown cell-based assays!  We will be there to answer your questions.

There's still time to register ..