Abstract: Liquified vitreous gel, prepared by a non-extractive technique, has been found to contain a cell proliferation inhibitor whose molecular size is greater than 10,000 daltons. Vitreous isolated from both bovine and chick embryo sources has been found to contain such an activity, which inhibits the growth of endothelial cells prepared from calf aorta. Culture medium conditioned by exposure to calf vitreous hyalocytes (cells found on the periphery of the vitreous gel), is also a source of the high molecular weight inhibitor.The high molecular weight inhibitor is prepared by chromatography of vitreous or hyalocyte-conditioned medium on a column of Bio Gel P-10 or by ultrafiltration. Mateial appearing in the void volume of Bio Gel P-10 (the material whose molecular size is too large to allow it to enter the gel) has a molecular size greater than 13,000 daltons.

Abstract: This invention comprises preparing a cell proliferation inhibitor by a nonextractive method from a tissue which has neither a high content of collagen, nor proteoglycans. The source of inhibitor comprises hyalocyte cells, which release the inhibitor into culture medium. The inhibitor is isolated from the culture medium. By chromatographic separation fractions are provided of varying molecular weight. Fractions both below and above a molecular weight of about 13,000 daltons show inhibitory activity.

Abstract: An inhibitor of endothelial cell growth is prepared by directly liquifying vitreous gel, as for example, forcing vitreous gel through a small orifice so as to directly convert the gel into a liquid, removing insoluble and suspended material and chromatographically fractionating the liquid and isolating the fractions. An inhibitor is also prepared by culturing hyalocyte cells in a medium and chromatographically fractionating the medium.