Trading trash: why the U.S. won't sign on to the Basel convention.

Environmentalists worry that hazardous wastes produced in industrialized nations are being dumped in cash-starved developing countries--the countries with the least political or economic clout to resist and the fewest resources for managing these toxic imports. Imported waste can pose a serious threat to the health of human populations and ecosystems if not managed appropriately. In 1989, the international community initiated efforts to reduce the flow of hazardous wastes from industrialized countries to developing countries by drafting a treaty known as the Basel Convention on the Control of Transboundary Wastes and their Disposal. The convention's mission is to strictly regulate the international transfer of hazardous wastes and to ensure that wastes are managed and disposed of in an environmentally sound manner. Although the United States supports the convention in theory, it remains the only industrialized country within the Organization for Economic Cooperation and Development yet to ratify it. However, legislation drafted by the Clinton administration that is soon to go before the 106th Congress could make the United States a party to the convention.

THERE iS considerable evidence that the progressive growth of solid tumours is dependent on their ability to induce the growth of new blood vessels from their host, (Folkman, 1978;Gullino, 1978). Accepted 11 Jtune 1979 Original work by Folkman et al. (1971) indicated that such neovascularization was induced by a humoral mediator secreted by the tumour, which they called tumour angiogenesis factor (TAF). They reported -1r IG. I. tA)1;llRc' eiorioauianitoic membrane, (UArNI) slowing a strong neovascular response to purified TAF. The bloo(d vessels can be seen to proliferate in a "spoke-whlieel" pattern con-erging tox%vards the souirce of TAFI'. (B) A control CAMI treated with lactose alone. For thlis assay fertilized chicken eggs arc iincuibated in a humi(lified incubator at :373C. After wiping with beta(line, a small lhole is (lrille(l in the shell of 3-day-old eggs an(l -1 ml of albumin is aspirated witlh a 19-gauge needlle. Tlhe next day a rectangular win(low (1 x 2 5 cm) is cut along the hiorizontal axis of tlhe egg an(t the shell anid slhell membrane are removcd. The wvindow is seale(l with sellotape, and the eggs ieturned to the incubator. On the 10th (lay a flat rectangular glass marker is placed on the clorioallaintoic mcmbrane. A small lhole is; madle in the membrane + 1 cm to the riglht of the marker with a :30-gauge dlental nee(lle. Purified TAF in freeze-clried pow(der form witlh lactose as a filler is placed( ovcr the lhole. The powder quickly dissolves and the window is resealed. The chot-ioallanitois is examinied for niewblood-x-vessel growtl (laily for 4 days. *:: RNA, 10% protein and 50%0 carbohydrate, the remainder probably being lipid. Subsequently Folkman and his coworkers purified a non-histone protein from tumour-cell nuclei which was also capable of inducing neovascularization in vivo (Tuan et al., 1973). Using the tumour extraction method proposed by Folkman et al. but modified to omit the trypsin step and introducing an antibody raised against crude TAF (Phillips & Kumar, 1979) we have isolated a very low molecular weight (-200) (Fig. lI). It is also capable of stimulating growth of endothelial cells in culture (Schor et al., unpub.).
Crude TAF (mol. wt , 105) resulting from gel filtration on Sephadex G100 of the treated tissue homogenate was freezedried and served as starting material for the subsequent purification. The first step was the separation of protein components by chromatography on DEAE cellulose using a convex salt gradient between 0 and 0-3m NaCl. At the end of the gradient the column was further washed with 0-5M NaCl. Activity could generally be detected in one or two of the eluted peaks, but the eluting positions of active material varied in different batches of TAF. Fig. 2 gives the position of the active peaks in 5 batches of TAF tested. All fractions from the DEAE column were applied individually to an affinity-chromatography column prepared by coupling absorbed TAF anti-  (Phillips & Kumar, 1979).

494
'a L-I '\-lps --A, body to CNBr Sepharose by conventional methods. The bound material was eluted with 50mM ammonium acetate buffer (pH 3.7) and, after freeze drying to remove the volatile ammonium acetate buffer, it was tested for activity using the CAM assay system. Detection of the bound material by conventional UV detectors was difficult, as only a small "blip" on the E254 absorbance line could be seen (Fig. 3). A small "blip" was present even when no activity could be detected by biological test. The active peaks in Fig. 2 correspond to those peaks which gave a positive CAM result for absorbed material on TAF antibody-affinity chromatography. The experiments described have been repeated on more than 9 different batches of crude TAF and identical results obtained. The pattern of protein peaks obtained on DEAE cellulose chromatography differed from batch to batch. This probably reflects differences in exposure time to neutral proteinases Arhich we have detected in the crude mixtures. The variable position of TAF bouind to these protein fractions is interesting. It seems likely that they are acting as nonspecific carriers of TAF. In order to check whether a charge difference occurred in the protein carrier peak after removal of the active material, the unbound protein peak from the affinity column was dialysed, concentrated and reapplied to a DEAE cellulose column. The peak emerged in a position identical to its previous one. This suggests that the charge contribution of TAF to the overall charge of the protein carrier is not significant. On dialysis in ammonium acetate (pH 3.7) the bound material from an affinitychromatography column equilibrated within 30 min and the material outside the bag was highly active. Since this suggested that the active component was of low molecular weight we applied the bound fraction from an affinity column to a Biogel P2 column (excluLsion limit 2500 mol. wt) with 10% isopropanol in water as packing and eluting solvent. An active peak emerged from the included portion  (Fig.  3). The column effluent was monitored by measuring the extinction at 206 nm. The material was applied in a total xolume of 5-15 ml. The activre peak is marked with an arrow. Gel filtration was by upwTard flow in 10% isopropanol water (20 ml/h) at 4°C.
Chlromatographically pure isopropanol (BDH Ltd) was used in all experiments. The eltution position of known amino aciel and peptide markers is shown. The activle material can be seen to elute at a mol. w t ')osition of 200. The majority of the inaterial in this area is non-specific impurity, as shown by controls.
of the column at a volume which corresponded to a mol. wt of -200 (Fig. 4). (This figure must be an approximation since in this system we do not find a straight-line relationship between all marker molecules of known mol. wt below 500, although the amount of variation from linearity is not great). The active peak was followed by 2 much larger but lower mol.-wt peaks which were inactive. The rapid equilibration of the material between the retentate and dialysate and the position of its elution on Biogel P2 indicate a very low mol. wt. The chemical nature of the small molecule, which we believe to be the true tumour angiogenic factor, is currently being investigated. It is not a prostaglandin, a protein or a peptide and neither is it a nucleic acid. We are also interested in the carrier molecules involved, as these may be either artifacts of preparation or natural binding carriers which are needed for transport of the molecule in vivo.
It may be of interest that neither our purified TAF nor an angiogenic factor which we have detected in synovium from an actively inflamed ankylosing spondylitic joint (results to be published) gives a precipitin line against TAF antibody. This may be due to the small size of the angiogenic factor(s). Human kidney tumours, which are the only human tumours we have so far investigated, do share com mon antigenic determinants with rat TAF (Phillips & Kumar, 1979). It is likely that angiogenic factor or factors are not unique to tumour cells, but that there is an excess production of them in the malignant cell. We feel that once the chemical nature of the angiogenic factor is established, it mav have both prophylactic and diagnostic implications in huiman mnalignant disease, or in other conditions wvhere angiogenesis is a feature. This work was partly finanled(1 by a grant to J.B.T. from the Arthritis andl Rheumatism Council, ancl by a grant to S.K. from the C:ancer Research Campaign.