Factor VIII-related antigen in canine endothelial neoplasms: an immunohistochemical study.

Canine vascular tumors (47 hemangiomas, 36 hemangiosarcomas) were investigated for the endothelial cell marker factor VIII-related antigen (F VIII RAg). The primary antibody was a commercial rabbit anti-human (r/h) F VIII RAg antiserum. All (100%) hemangiomas and 32 (89%) of 36 hemangiosarcomas stained for F VIII RAg. One hemangiosarcoma (3%) was negative, and three tumors (8%) were equivocal in staining. Rarely, the interpretation of stained immature endothelial cells was difficult. The r/h F VIII RAg antibody was a positive marker of normal, reactive, and neoplastic endothelial cells in the dog.

Malignant histiocytosis with marked cellular atypia--an autopsy case with an immunohistochemical study on neoplastic histiocytes.

A 71-year-old male presenting high fever, pancytopenia, liver dysfunction and jaundice died without a confirmed diagnosis. Microscopically, histiocytes with marked atypia and erythrophagocytosis had infiltrated the spleen, enlarged lymph nodes, liver, and bone marrow. From the above features this case was diagnosed as malignant histiocytosis. The infiltrating histiocytes were classified into three categories: 1) phagocytic cells, 2) atypical, mostly non-phagocytic cells, and 3) bizarre cells including multinucleated giant cells. An immunohistochemical study of histiocyte markers demonstrated that lysozyme was positive in the atypical cells and some phagocytic cells, whereas alpha-l-antitrypsin tended to be localized in the phagocytic cells. Bizarre cells were negative for both markers. No S-100 protein was demonstrated in the neoplastic cells. These immunohistochemical features suggested monocyte-phagocytic origin of the tumor in this case.

Differences in the peripheries of Lewis lung tumor cells growing in different sites in the mouse.

The peripheries of Lewis lung (3LL) tumor cells growing in different organs of the mouse were studied by cell electrophoresis and electron microscopic quantitation of colloid iron hydroxide (CIH) adsorption before and after incubation with neuraminidase. The results show that cells growing in the kidney after direct injection have significantly higher anodic mobilities than cells growing in the subcutaneous sites from which they were derived, or in intramuscular sites, liver or spleen. The proportional contributions of cell surface sialic acids were similar in all sites. Electron microscopy of cells reacted with CIH indicates that the increased surface charge density of the tumor cells growing in the kidney is due to the presence of increased densities of non-CIH-binding ionogenic groups. Before neuraminidase treatment, the surface distribution patterns of CIH were indistinguishably random for 3LL cells growing in all sites. After neuraminidase treatment, significantly more clustering of CIH particles was observed on 3LL cells with a history of growth in the kidney than in subcutaneous sites. The changes observed in the 3LL cells growing in the kidney were irreversible, and persisted on multiple back-transplantation to subcutaneous sites. Detailed analysis of the results shows the changes to be due to the preferential selection of a subpopulation consisting of approximately 10% of the original (subcutaneous) tumor-cell population. This evidence for an irreversible site-induced selection of a pre-existing sub-population of 3LL cells contrasts with the reversible (modulation) site-induced adaptation previously observed by us in Walker-256 cancer cells, and therefore indicates that both selective and adaptive processes can occur. Even in the case of the 3LL cells, site-specific selection is not general, since the changes were observed in tumors growing in the kidney but not in the other anatomic sites. At present we cannot comment on the relevance of these reported changes to naturally occurring metastasis.

Presence of a novel spleen focus-forming virus-specific glycoprotein (gp51) in a Friend leukemia cell line and its decrease during erythrodifferentiation.

All Friend leukemia cell lines induced by polycythemic strains of Friend leukemia virus complex express an appreciable amount of spleen focus-forming virus (SFFV)-coding envelope gene (env)-related glycoprotein with a molecular weight of 55 kilodaltons (gp55). A clonal, highly differentiation-inducible Friend leukemia cell line, T3-C1-2-O(2-O), possesses not only gp55 but also gp51 as SFFV-specific gene products. The peptide map of gp51 is quite similar to that of gp55 and the difference in their molecular weights is primarily dependent on their oligosaccharide content. In the differentiation-induced state, gp51 becomes far less detectable than gp55 in 2-O cells. The biological significance of this novel SFFV-coding glycoprotein is discussed.

Fractionation of Marek's disease virus-induced lymphoma by velocity sedimentation and association of infectivity with cellular fractions with and without tumor antigen expression.

Cell suspensions of lymphomas induced by Marek's disease (MD) virus were fractionated by sedimentation at unit gravity on a continuous gradient of bovine fetal serum. Cells in various fractions were examined for MD tumor-associated surface antigen (MATSA) by indirect immunofluorescence, using specific antibody, and for viral infectivity by cocultivating fractionated cells with permissive monolayer cells of duck embryo fibroblasts. Most MATSA-bearing cells in the lymphomas sedimented at a sedimentation velocity of greater than 3.0 mm/hour, whereas smaller, slow-sedimentating cells were generally devoid of MATSA expression. Viral infectivity was associated with MATSA-bearing and MATSA-lacking fractions. Within the limits of the experimental procedures used, this observation provided evidence that presence of MD virus genome in lymphocytes doses not result in concurrent expression of detectable MATSA and that MATSA likely represents another stage of interaction between MD virus and certain lymphocytes.

Isolation and characterization of heparin from human mastocytoma tissue.

Polysaccharide was isolated from human spleen mastocytoma by proteolytic digestion, precipitation with cetylpyridinium chloride, digestion with chondroitinase ABC, and ion-exchange chromatography on DEAE-cellulose. The final product (0.7 mg per g of starting material, MW 8000) behaved like standard heparin on ion-exchange chromatography and on electrophoresis, and contained D-glucuronic acid, L-iduronic acid, D-glucosamine and sulfate in the proportions expected for heparin. Affinity chromatography on antithrombin-Sepharose separated a distinct high-affinity fraction (4-5% of the total material). Structural analysis of this fraction showed that about 10% of the D-glucosamine residues were N-acetylated, the remainder N-sulfated. The anticoagulant activity of the isolated heparin was 71 B.P. units per mg (whole-blood system), or 30 units per mg (anti-thrombin and chromogenic substrate). 205 and 10-15 units per mg (chromogenic assay) were found for high and low affinity fractions, respectively. These results demonstrate conclusively the occurrence of heparin in a human tissue.

[Analysis of the cobalamin coenzymes in mouse splenic tumor cells]. / Analiz kobalaminovykh kofermentov v opukholevykh kletkakh selezenki myshei.

Coabalamine coenzymes were studied in tumor spleen cells of mice with La leukosis. Endogenous cobalamines in the cell extracts were separated by two-dimensional thin-layer chromatography and by bioautography. Analysis of the cobalamines ratio was carried out using bioautochromatographic technique. 5-deoxyladenosyl- and methyl cobalamines were found in extracts of the tumor cells.