It is a simple fact that small amounts of amyloid will not polarise to the extent (vividness) of large amounts. The struggle then is to identify them. If they stain with Sirius red are in an appropriate place, and have the right appearance, then any amount of light to polarise it is OK with me. 

In parenthesis, why are the controls for amyloid always from solid amyloid spleens etc.? That is to say - loaded.
Surely the faintest amount of amyloid is the appropriate control.

Terry L Marshall B.A.(Law), M.B.Ch.B., F.R.C.Path
Consultant Histopathologist
Rotherham General Hospital, Yorkshire
terry.marshall@rothgen.nhs.uk

-----Original Message-----
From: d.segers@planet.nl [mailto:d.segers@planet.nl]
Sent: 17 December 2002 15:16
To: histonet@pathology.swmed.edu
Subject: Analysis of sirius red with polarized light


Dear all, 

In the process of analysis of our picro sirius red stained sections we ran 
into a discussion on the microscope prefs. We could not come to a conclusion 
as to how much light must be given. We use 2 polarization filters in crossed 
position. Some people want to give minimal light in order to prevent 
overestimation of collagen content, total background is black. Others say to 
give full light, but than the background becomes somewhat blueish, which 
cannot be turned to black by adjusting the filters. 
Does anyone have experience with different lighting on sirius sections? Or is 
anyone aware of literature in which this problem is discussed. 

Thanks in advance, 

Dolf Segers 
Dept. of Experimental Cardiology 
Thoraxcentre, Erasmus MC Rotterdam 
The Netherlands