Method of analysing a sample of free cells

Abstract

A method of determining a measure of the number of platelets in a cell suspension containing platelets. The number of small particles in the suspension is counted. The suspension is agitated in the presence of a gas. The number of small particles in the suspension after agitation is counted. The two counts are compared to obtain a measure of the number of platelets.

1 . A method of determining a measure of the number of platelets in a cell suspension containing platelets, the method comprising the steps of: 
 counting the number of small particles in the suspension;    agitating the suspension in the presence of a gas;    counting the number of small particles in the suspension after agitation; and,    comparing the two counts to obtain a measure of the number of platelets.    
     
     
         2 . A method according to  claim 1 , in which the gas is air, or one or more of its constituent gases.  
     
     
         3 . A method according to  claim 1  or  2 , in which one or more aliquots of the suspension are passed through a particle counter before the suspension is agitated to obtain a first count of the number of small particles and subsequently one or more other aliquots of the suspension are passed through a particle counter after agitation to obtain a second count of the number of small particles in the sample.  
     
     
         4 . A method according to any preceding claim, in which the cell suspension is isotonic.  
     
     
         5 . A method according to any preceding claim, in which small particles having a volume of at least 7 femtolitres are detected to obtain a count of the number of small particles in the suspension.  
     
     
         6 . A method according to any preceding claim, in which the suspension is subjected to a series of alterations in osmolality and a count of the number of small particles in the suspension obtained at a number of different osmolalities.  
     
     
         7 . A method according to any preceding claim, in which at least one of the air quantity in contact with the suspension, the intensity of agitation, and the duration of agitation, is measured.  
     
     
         8 . A method of analysing a sample of free cells in vitro comprising the steps of: 
 applying a known or identifiable quantity of stress to the sample;    measuring the sample before and after the application of stress to provide at least one reading from which quantitative information relating to the number of cell fragments in the sample caused by the applied stress can be determined; and,    relating this reading to the quantity of stress to provide an indication of cell friability.    
     
     
         9 . A method according to  claim 8 , in which the applied stress is at least one of the group consisting of mechanical, chemical, thermal, sonic, light, electric, electromagnetic, and an alteration in osmolality.  
     
     
         10 . A method according to  claim 8  or  9 , in which a range of stresses are applied so as to obtain a plot of the relationship between the number of cell fragments and the applied stress.  
     
     
         11 . A method according to  claim 8  or  9 , in which the sample is subjected to an osmotic gradient.  
     
     
         12 . A method according to  claim 10  or  11 , in which measurements are made at a number of different osmolalities so as to obtain data describing the relationship between the number of cell fragments and the applied stress.  
     
     
         13 . A method according to any of  claims 8  to  12 , in which detection thresholds used to count the number of particles are set sufficiently low to detect cells down to a volume of substantially zero femtolitres.