Background Without angiogenesis, tumours cannot grow larger than a few millimetres in size, the limit of diffusion. Vascular endothelial growth factor (VEGF) is an endothelial-specific mitogen and is a major regulator of physiological and pathological angiogenesis. Higher levels of VEGF messenger RNA expression and VEGF production and secretion have been found in FTC-133 cells than normal thyroid cells. Methods To investigate the relationship between VEGF and thyroid tumour angiogenesis and growth, human dermal matrix inoculated with FTC-133 cells was xenografted into nude mice or directly injected subcutaneously. To block the function of VEGF, the neutralizing anti-VEGF monoclonal antibody A.4.6.1 (mAb A.4.6.1) was injected intraperitoneally 100 μg per 0·2 ml twice weekly. As control, an antibody of the same isotype (immunoglobulin G1), directed against the gP120 protein (Ab 5B6), or phosphate-buffered saline (PBS) was used. To evaluate the dermal matrix as a model for angiogenesis studies, rhVEGF was inoculated into the dermal matrix pocket and xenografted into mice. Results In vivo study using the dermal matrix showed that the number of blood vessel ingrowths paralleled the concentration of rhVEGF and was highest at the concentration of 100 ng ml−1. Mice treated with the mAb A.4.6.1 developed fewer blood vessels (mean 7 per high-power field (HPF)) than control mice (18 per HPF in Ab 5B6 and 22 per HPF in PBS) (P < 0·01). The size of tumours between mAb A.4.6.1- and Ab 5B6- or PBS-treated groups showed a significant difference from the second week after the inoculation of FTC-133 cells. The tumours from mice treated with mAb A.4.6.1 were smaller (mean(s.d.) 0·09(0·02) g at 5 weeks) than tumours from mice treated with Ab 5B6 (5·38(1·15) g) or PBS (4·00(0·72) g) (P < 0·001, two-tailed unpaired t test). Conclusion VEGF is produced by thyroid cancer cell line FTC-133 and stimulates angiogenesis and growth of thyroid cancer. More importantly, this stimulation can be blocked by mAb A.4.6.1.

The Advanced Light Source (ALS) is a synchrotron radiation facility based on a low-emittance, 1.5-GeV electron storage ring presently under construction at the Lawrence Berkeley Laboratory, U.S.A. Plans are under way to develop a polarized photon facility at the ALS, exploiting the natural polarization properties of the bend magnet synchrotron radiation. The radiation emitted in the plane of the storage ring is linearly polarized, while above and below the plane it is elliptically polarized. We will utilize these properties to obtain circularly polarized soft x rays. A participating research team (PRT A018) has been formed and is proceeding with the design of a high-resolution beamline in the soft x-ray energy region 100–1500 eV. Intense beams of monochromatic, tunable, pulsed, circularly polarized photons will become available. We will discuss the physical characteristics of this polarized soft x-ray source. New investigations in biology, materials science, physics, and chemistry will become accessible. Initial experiments using circularly polarized photons in the soft x-ray region are planned in the areas of differential scattering and absorption from chiral molecules and probing the electronic and magnetic properties of magnetic systems. This work was supported by the U.S. Department of Energy (DE-AC03-76SF00098).