Anti D dimer monoclonal antibodies: a possible scintigraphic agent for immunodetection of thrombi.

The aim of this work was to produce a MoAb able to react with clots but not with fibrinogen. Monoclonal antibodies directed towards DD dimers, against specific products of plasmic digestion of cross-linked fibrin, were obtained. One of these antibodies, F 60/43/8, showed a 1.79 x 10(9) l mol-1 binding constant in spite of the presence of fibrinogen at a 4000 times greater concentration than the cross-linked fibrin. In vitro studies with 125I-F(ab')2 of F 60/43/8 showed that 34-80% of the radioactivity can be found in human clots, in the presence of physiologic concentrations of fibrinogen, and that 96-h washing does not remove the labelled F(ab')2 from the clot. 131I-F(ab')2 was injected into rabbits in which a clot had formed in an artery (six rabbits) or in a vein (six rabbits) of the left ear. Scintigraphic images of the clot were always obtained. In conclusion, the results of this work suggest that F 60/43/8 may be used as a specific antibody for the radioimmunodetection of thrombi.

Technetium-99m sestamibi: an indicator of breast cancer invasiveness.

As recently shown, angiogenesis is the most reliable marker of breast cancer invasiveness. Unfortunately it must be assessed by immunohistochemistry on tissue specimens. We have used technetium-99m sestamibi, a marker of regional blood flow in other organs that often but not always images breast cancer, to assess the invasiveness of this tumour. Nineteen patients, ten with nodal metastases and nine without any metastases, were studied with 99mTc-sestamibi scintigraphy before operation. Angiogenesis was quantitatively assessed by immunohistochemical staining of endothelia for factor VIII. All the node-positive (N+) patients at surgical revision showed a positive 99mTc-sestamibi scan of the primary tumour and all the N-patients were negative. Nine out of ten N+ and sestamibi-positive tumours showed more than 135 microvessels/mm2 and one showed 99 microvessels/mm2; by contrast there were 71.6 +/- 12.1 microvessels/mm2 in the nine N- and sestamibi-negative tumours. Our study suggests that 99mTc-sestamibi is a marker of breast cancer invasiveness: its uptake is related to angiogenesis and, possibly, to oxidative metabolism of the tumour.