Heather,
I am pretty expert with factor XIIIa. FXIII is a plasma proenzyme that
circulates in the plasma as a tetramer of two active a subunits with two
non enzymatic b subunits. The active a dimer is split from the carrier
protein B subunits by a calcium dependent cleavage in the presence of
thrombin. The a subunit is produced intracellularly by monocytes, dendritic
connective tissue histiocytes, lymph node sinus histiocytes,platelets, and
megakaryocytes. Plasma factor XIIIa catalyzes the formation of cross-
linking peptide bonds between glutamine and lysine residues on fibrin in
the last part of the coagulation cascade. Cellular FXIIIa cross links
fibronectin and collagens and promotes the spreading and adhesion of
fibroblasts in healing wounds and tumors (do a Medline search under Factor
XIIIa Silverman JS for references) . I use the Calbiochem (La Jolla,
CA,USA) product- concentrated rabbit anti-human coagulation factor XIIIa
diluted 1:400 in phosphate buffered saline with 1% bovine serum albumen
added. Incubate for 30 minutes at room temp. Formalin-fixed paraffin
embedded tissue needs a 30 minute incubation in trypsin at 37 degrees C, I
use the Sigma pre buffered tablets. Microwave antigen retrieval is
undesirable overkill and produces background staining. The stain is usually
very clean,  and immature placenta or a dermatofibroma of skin are good
controls. E mail me if you need more help. 
Jeff Silverman 
Southampton Hospital NY USA
peptolab@hamptons.com

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> From: Mcleod, H, Heather <HMCLEOD@chempath.uct.ac.za>
> To: histonet@Pathology.swmed.edu
> Subject: factor X111a
> Date: Tuesday, May 11, 1999 7:29 AM
> 
> Dear Histonetters
> 
> We will soon have to order factor X111a, an antibody not frequently  
> requested in our laboratory and seems to not be freely 
> available.  Does anyone use the biogenesis product?  Any information 
> with regards to its optimal dilution, antigen retrieval etc wil be 
> greatly appreciated. For the record we have been using a Behring 
> product and have not been able to locate an agent (are they still in 
> existence)
> 
> mcleod