Sven,
I have just been handed a reference on this subject.  Here is the article
info:

© The Histochemical Society, Inc. 0022-1554/02/$3.30 213
ARTICLE
Volume 50(2): 213–222, 2002
The Journal of Histochemistry & Cytochemistry
http://www.jhc.org
Semi-automated Method of Quantifying Vasculature of
1-Methyl-1-nitrosourea-induced Rat Mammary Carcinomas Using
Immunohistochemical Detection
John N. McGinley, Katrina K. Knott, and Henry J. Thompson
Center for Nutrition in the Prevention of
Disease,                                            AMC Cancer Research
Center, Denver, Colorado
SUMMARY Studies of the vascularization of autochthonous rodent mammary
tumors are limited in number, and the majority have used Factor VIII
staining for blood vessel detec-tion.  Moreover, little effort has been
directed at measuring the vascularization of tissue immediately adjacent
to a tumor despite its central importance in the process of angiogen-esis.
Thirty-six chemically-induced mammary carcinomas and tissue immediately
adjacent to
these carcinomas were used to develop a census counting method for
quantitative assess-ment of intra- and extra-tumor vascularization. Blood
vessels were identified using antise-rum directed against either CD31 or
Factor VIII. Techniques used to create digitized images of all tumors and
the semi-automated methods for circumscribing the extra-tumoral region are
described. For Factor VIII, CD31 allowed greater discrimination of blood
vessels with ar-eas 25 m 2 and demonstrated crisp staining of blood
vessels, with minimal background and excellent preservation of tissue
architecture. Census counting data support the use of CD31 for quantifying
both intra- and extra-tumoral vascularization. This method provides a
basis for standardizing the approach to evaluation of experimentally
induced premalig-nant and malignant mammary lesions in rodent model
systems used to investigate poten-tial anti-angiogenic cancer preventive
agents.                  (J Histochem Cytochem 50:213–222, 2002)


Sven Terclavers wrote:

> Hi listers,
>
> Does anyone of you know of a protocol to stain CD31 without the use of
> trypsine?!
> Greetz,
>
> Sven