We have studied a murine tumor previously classified as a poorly differentiated chondrosarcoma. Although the cells in this tumor are surrounded by large quantities of extracellular matrix material, the matrix fails to react with stains specific for the sulfated glycosaminoglycans present in normal cartilage. Here we show at the ultrastructural level that the tumor matrix is a homogeneous, nonfibrillar material, resembling basement membrane. Neither the proteoglycan matrix granules nor collagen fibrils characteristic of cartilage are present in the tumor matrix. Amino acid analyses of whole tumor tissue, enzyme-solubilized tumor components, and the protein extracted from lathyritic tumors confirmed that the tumor matrix is a basement membrane collagen. The collagenous protein extracted from the tumor by nonenzymatic means contains three unique polypeptides larger than the alpha-chain components of the other types of collagen. These studies indicate that the tumor is not a type of chondrosarcoma but a basement membrane producing tumor.

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Fifteen instances of intramural coronary arteries were observed in the dissection of 276 human hearts at consecutive unselected autopsies. All but 2 of these 15 had severe atheromata and narrowing of the lumina. It was thought important to determine whether or not the covering of the artery by cardiac muscle for a major part of its course protected the artery from atherosclerosis. From our data, one may assume that those portions surrounded by heart muscle were not protected from atherosclerotic process which occurred there as well as in extramural portions of the same arteries and in other entirely extramural coronary arteries.

Originally, the tumor arose spontaneously in a Sprague-Dawley rat; it has been maintained by subcutaneous implantation for over 5 years in rats of the BUF/N strain. At the 10-12th week after transplantation, the tumors measure at least 40 X 50 X 50 mm and weigh 22-25 g. The tumor persists and grows in noninbred Sprague-Dawley rats, and in strains derived from the Wistar, in addition to the BUF/N rat (R. Swarm). This preliminary report will describe two sets of experimental data. (a) the isolation and properties of the mucopolysaccharides, and (b) the isolation and some properties of the protein-polysaccharide of this tumor. METHODSProteolysis and analytical methods were performed as described (3). GlcN and galactosamine (GalN) were determined after hydrolysis with 4 N HCl for 12 hr in an evacuated tube on a Beckman model 120 autoanalyzer. Galactose and xylose were determined on a column of 3% ECNSS-MI on a Gas Chrom Q after hydrolysis for 16 hr with 2 N H2SO4, passage through ion-exchange columns, reduction with borohydride, and peracetylation (4). Testicular hyaluronidase was purchased from A. B. Leo, HAlsingborg, Sweden, and contained 20,000 IU/mg. It was free of protease as determined viscometrically at 370C with gelatin as substrate. The gelatin was a purified and lyophilized sample of Gold Label French gelatin.Hyaluronidase digestion was in 0.1 M sodium acetate buffer (pH 5.0) containing 0.15 M NaCl at 560C for 3 days. RESULTS Isolation of mucopolysaccharidesFor isolation of mucopolysaccharides, the acetone-dried tissue (6.9% of the wet weight) was exhaustively digested with papain and pronase, followed by alcohol fractionation, a modified cetylpyridinium chloride (CPC)-column fractionation (5), and gel filtration. The isolated material (1.5% of the wet weight) consisted of 97.8% chondroitin 4-sulfate, 1.2% hyaluronate, and 1% of a complex mixture of glycopeptides.Keratan sulfate (KS) was absent, as was evident from the absence of GlcN in the chondroitin sulfate fractions. Hyaluronic acid was characterized by analysis, optical rotation, enzymatic digestion, gel chromatography, and electrophoresis. The chondroitin sulfate fraction proved to be entirely the 4-sulfate isomer, as evidenced by the IR spectrum and by specific chondroitinases and sulfatases (6). The fraction was completely digested by testicular hyaluronidase. CPC fractionation on a cellulose column and gel filtration on an 8% agarose column separated the chondroitin sulfate into three fractions, differing in chemical composition, molecular weight, and sulfate content. The main fraction was fully sulfated and had the highest molecular weight and the lowest peptide content. The two minor fractions were undersulfated and had the lower molecular weight and the higher peptide content. The molar ratio of serine to xylose was fairly constant, while the galactose to xylose ratio was 2.7-2.9, i.e., significantly higher than 2 (7). The chain length, calculated from the ratio of hexosamine to xylose, gave 51.4, 30