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The organization of treatment for patients with malignant intraocular tumors is described with reference to the oncology department of an eye clinic specializing in tumor problems. Since eye tumors are seldom encountered in day-to-day ophthalmological practice, and the costs of diagnosis and treatment are so high, centralized treatment facilities are advocated.

Morphological changes occurring in the rabbit retina after fast neutron irradiation levels of 250,500 and 1,000 cGy are discussed. The threshold dose that may cause damage to retinal structures is 250 cGy.

To examine the specific effects of individual basement membrane components on the behavior of transformed cells of epithelial origin, ethionine-transformed cells and control cells at low and high passage levels were seeded on glass that had been coated with fibronectin, laminin, or type IV collagen. The cells used were sublines of the liver-derived TRL 1215 epithelial cell line, a line in which transformation has been shown to be accompanied by increased cell-substrate adhesion and cell spreading. Cell spreading on the different basement membrane components was determined by morphometry, and growth (proliferation) was measured by protein and DNA analyses. Laminin increased spreading and growth in transformed and control sublines. Laminin also induced changes in cell shape that were indicative of increased cell motility. For the control cells, fibronectin and also type IV collagen were less effective than laminin in stimulating cell spreading and growth. However, for the ethionine-transformed cells, fibronectin was as effective as laminin in stimulating cell spreading. With the exception of the spreading response to fibronectin, the ethionine-transformed cells were less sensitive to the defined substrata than were the control sublines. Moreover, only the ethionine-transformed cells were able to proliferate in serum-free medium. Thus, greater autonomy is characteristic of transformation for these epithelial cells and is exemplified by the reduced influence of and dependence on exogenous factors, both substrate-bound and soluble, for spreading and growth.

Studies were made on the oncogenic response of 3086 young chicks to i.v. inoculation of MC29 avian leukosis virus from blood plasma of previous-passage birds or the supernatant fluid of cultures of chick embryo cells infected with strain MC29. Among the large variety of neoplasms of other tissues previously described, there occurred a high incidence of primary growths of the liver. Pathomorphology of the growths frequently differed greatly in both different hosts and the same bird, but some uniformity of the types of neoplasms was evident in many animals. Despite much variation in histopathology, the large proportion of growths could be grouped in several distinctive categories. Examinations by light and electron microscopy provided evidence of derivation of the tumors by alteration of hepatocytes originating principally in the portal regions as indicated by forms transitional from the parenchymal cells to the cells of the different types of growths. Neoplastic aspects of the growths were evident by infiltration and invasion of adjacent tissues, penetration of blood vessels, transplantability to other avian hosts (described in another report), and metastasis to distant organs including the lung, kidney, and spleen. There was no evidence of tumors arising from the biliary system, and growths of cells resembling the biliary type could be traced to altered hepatocytes. None of the findings suggested conversion of biliary-type cells to hepatocytes. Continued growth resulted in anaplastic and metaplastic changes in cell morphology and structural organization and in the formation of cartilage, osteoid, and sarcoma-like spindle-cell tumors of probable epithelial origin. Development of the growths wasnot associated with cirrhosis, and necrosis was limited to infrequent disseminated, essentially unicellular changes or necrobiosis of small groups of cells. The marked variations in the type of virus-induced growths demonstrated the remarkable capacity of cells morphologically inidistinguishable from the hepatocytes for the most diverse alterations in cell structure and tissue organization. This neoplastic response of hepatocytes to the MC29 strain constitutes the only demonstration thus far of the specific hepatocarcinogenic activity of an avian tumor virus.

Surface replicas of ts25-infected cells reveal the organization of virus-specific knobs prior to and during the early stage of budding, and antibody-mediated ferritin labeling suggests a transmembrane association of viral envelope and core components.

The level of gap-junctional (cell-cell) communication was studied by the radioisotope transfer technique in NIH 3T3 cells exposed to NiSO4, MgSO4, or both salts combined. Monolayered NIH 3T3 donor cells were labeled with [3H]-uridine for 3 h and then co-cultured with non-labeled recipient NIH 3T3 cells for 3 h in the presence of 0.5-20 mM NiSO4, 1.0-100 mM MgSO4, or 5 mM NiSO4 plus 1.0-100 mM MgSO4. 12-O-tetradecanoylphorbol-13-acetate (TPA), 16-160 pM, served as a positive control. The exposed cells were fixed with 2.5% glutaraldehyde and processed for autoradiography. The cell-cell communication rate was based on the number of radioactive recipient cells in relation to the total number of recipient cells for 100 donor cells. NiSO4 disrupted cell-cell communication in a dose-related manner from 98% of the base value at 0.5 mM NiSO4 to 2% at 5 mM NiSO4. Cell viability was not affected by 0.5-5 mM NiSO4. The inhibitory action of 5 mM NiSO4 could be partially prevented by 5.0-100 mM MgSO4. However, MgSO4 did not prevent the inhibition by TPA. The results indicate that NiSO4 is capable of inhibiting cell-cell communication at concentrations that do not cause cytotoxic effects in NIH 3T3 cells during a 3-h period. In this respect NiSO4 resembles such classical tumor promoters like TPA. The antagonism by magnesium of the nickel-induced inhibition of cell-cell communication may indicate a contributory mechanism by which magnesium counteracts the carcinogenicity of nickel in vivo.

TGF-beta is the prototype of a large family of multifunctional regulatory proteins. The principal sources of the peptide, platelets and bone, suggest that it plays a role in healing and remodeling processes. In vitro, TGF-beta is chemotactic for monocytes and fibroblasts and can greatly enhance accumulation of extracellular matrix components by fibroblasts. Its ability to stimulate the formation of granulation tissue locally and the demonstration of specific time- and tissue-dependent expression in embryogenesis suggest that similar mechanisms are operative in vivo. By analogy to its effects in wound healing and embryogenesis, it is proposed that TGF-beta, secreted by tumour cells, can augment tumour growth indirectly by effects on the stromal elements. These effects include suppression of the immune response, and enhancement of both angiogenesis and formation of connective tissue. Many tumour cells have escaped from direct growth inhibitory effects of TGF-beta by a variety of mechanisms including inability to activate the latent form of the peptide, loss of cellular receptors for TGF-beta, and loss of functional intracellular signal transduction pathways.

Ribosomal RNA isolated from ribosomes present inside avian myeloblastosis virus (AMV) was characterized by electron microscopy using the formamide-urea spreading technique. The molecular weight and the secondary structures were compared with those of r-RNA and precursor r-NA isolated from host cells, the leukemic myeloblasts. The molecular weight of viral r-RNA (1.62 +/- 0.18 X 10(6) and 0.69 +/- 0.10 X 10(6)) and the molecular weight of cellular r-RNA (1.63 +/- 0.18 X 10(6) and 0.67 +/- 0.09 X 10(6)), the latter obtained from avian myeloblasts, were found to be identical and comparable with the molecular weight of chicken liver r-RNA. Likewise, the secondary structures of viral r-RNA were identical to those of cellular r-RNA. The postulated possible precursor character of viral r-RNA was excluded, since the molecules of viral r-RNA do not show any similarity to those of precursor r-RNA. Previously observed differences in behavior of viral and cellular (myeloblastic) r-RNA in sedimentation and electrophoretic mobility are discussed.

The Madison lung (M109) tumor cell line, initiated from a "spontaneous", anaplastic murine lung carcinoma, has been propagated continuously in vitro for more than 300 cell generations. Cytogenetic analysis revealed a mouse karyotype with a mode of 78 chromosomes (2n = 40). Three distinct marker chromosomes were identified by trypsin-giemsa banding. The cells piled up in culture and had a short generation time and high plating efficiency. Electron microscopy revealed highly undifferentiated cells with little rough endoplasmic reticulum, an abundance of free polysomes, the presence of few and often odd-shaped mitochondria, lipid bodies and phagocytic vacuoles. Virus particles of the C-type were found frequently. The subcutaneous transplantation of M109 cultured cells at a relatively low cell inoculum produced highly metastatic tumors in syngeneic BALG/c mice.

Caenorhabditis elegans contains a family of vitellogenin genes consisting of five closely related genes (vit-1 to vit-5) coding for 186,000 Mr yolk proteins, and one distantly related gene (vit-6) encoding a 200,000 Mr precursor to two smaller yolk proteins. We demonstrate here that, although vit-1 to vit-5 are not clustered (with the exception of vit-3 and vit-4), they are all on the X chromosome. In contrast, vit-6 is autosomal. The genes are strictly regulated during development: they are activated in the intestine of the hermaphrodite worm, following the last larval molt. In order to determine whether the vit genes are contained within chromosomal domains of similarly regulated genes, we have used the chromosomal "walking" technique to isolate 55,000 to 60,000 base-pairs of DNA surrounding each of the X-linked genes and determined the developmental specificity of nearby genes. In the total of 235,400 base-pairs of cloned DNA, seven genes, in addition to the five vit genes, were found. The average gene spacing is approximately 20,000 base-pairs per gene but is highly variable, ranging from less than 2000 to more than 38,000 base-pairs. The seven newly identified genes, called uvt-1 to uvt-7, specify RNAs varying in size from 500 to 2700 bases. With the exception of uvt-4, all of the genes are developmentally regulated; but the patterns of regulation are quite variable, and all are different from the vitellogenin genes. The vit genes, therefore, are not contained within co-regulated chromosomal domains. We also searched for the presence of repetitive DNA, but only four such sequences were found.

Previous reports described the induction of avian renal neoplasms by leukosis virus strains BAI A [avian myeloblastosis virus (AMV)] and MC29, and illustrated morphological characteristics of the tumors. Continued studies in this work confirm evidence of the origin of the tumors from embryonal cells residual in the posthatched chick. The work further emphasizes differences in histopathology of the neoplasms caused by the two viruses and reveals differences in the histopathogenesis of the respective growths. Embryonal rests may consist of two types of cells, those of epithelial characteristics and a second element of differentiation between nephroblastema (mesenchyme) and epithelium and designated here as nephromesoblastoma. Infection by AMV induces tumors of epithelial characteristics and, in addition, derivatives of nephromesoblastoma consisting of cartilage, bone, areas of keratinization, and sarcoma. Keratinized structures in the nephroblastoma originate from nephromesoblastoma. In contrast, MC29 virus induces only epithelial growths representing principally aberrant and malformed glomerular and tubular structures with occasional cartilage derived from epithelial cells. MC29 tumors are completely lacking in nephromesoblastoma tissue and contain no bone, sarcoma, or keratinized formations. In MC29 tumors, occasional cartilage was derived from epithelium. Tumors caused by AMV exhibit the complex structure of nephroblastoma with all of the features of the growth in humans (Wilms' tumor). The neoplasms induced by both AMV and MC29 exhibit marked aberration, distortion, and malformation in the differentiation of the cells growing out from the embryonal rests representing rare manifestations of cell genetic influence inherent in the primordial growth of nephroblastema. The results thus illustrate fundamental differences in cellular composition and capacity to respond to etiologically different leukosis viruses.

A study of 586 dentists and 553 dental assistants revealed that the contamination of dentists with hepatitis B was three times higher than in the comparable control group. No elevated hepatitis B morbidity rate however could be determined for the dental assistants. The occupation-related risk of hapatitis B infection was one case for every 100 dentists per year. No serologic differences from the normal control group could be determined for dentists and dental assistants in regard to contamination with hepatitis A. The evaluation of the questionaire showed that most dentists and their assistants were not aware of their hepatitis infection. Protective epidemiologic and hygienic measures, for the most part, were not observed.

The relationship between cytoskeletal changes and oncogene expression in initiated cells during exposure to a tumor promoter was investigated in the phorbol ester-sensitive murine epidermis-derived cell line JB6 (P+ cells) and its promotion-insensitive variant (P- cells) using immunocytochemical methods, soft agar assays, and tumorigenicity tests in nude mice. Cytoskeletal changes in P+ and P- cells induced by short-term incubation with 12-O-tetradecanoylphorbol-13-acetate (TPA) were similar. Prolonged incubation with TPA allowed P- cells to regain their original appearance and resulted in growth inhibition; however, the extended presence of TPA produced in P+ cells persistent alterations in the distribution of actin, vinculin, and fibronectin. P+ cells proceeded to develop multilayered foci. Using monoclonal antibodies, we detected the H-ras oncogene-encoded Mr 21,000 protein (p21) exclusively in focus-forming cells. Both the observed morphological changes and the expression of p21 were reversible in P+ cells when TPA exposure was terminated soon after foci had developed. In order for TPA-treated P+ cells to grow as tumors in nude mice, multiple cycles of exposure to TPA in conjunction with clonal expansion in agar were necessary. The results indicate that there exists during promotion of the P+ JB6 cells a relationship between expression of the H-ras gene product p21 and enhanced proliferation with focus formation and that both expression of p21 and focus formation depend on the continuous presence of the promoting agent.

The replicative cycle of herpesvirus ateles, strain 73 (HVA-73), was examined in the electron microscope and compared to that of other herpesviruses known to be oncogenic. A relatively slow replicative cycle of HVA-73 in owl monkey kidney (OMK) cells allowed us to distinguish cytoplasmic and nuclear stages of replication, comprising virus uptake, transport, maturation, and extrusion. Virus uptake was observed within 10 hours of infection and occurred both as a result of fusion between virus and cell membranes and by phagocytosis. Morphologic evidence for the transfer of viral DNA from nuclecapsids to the nucleus at the nuclear membrane is presented. This is shown by the location of numerous empty capsids in front of nuclear pores early during infection. Towards the end of the eclipse phase, at about 48 hougs after infection, two different types of nuclear inclusion bodies were observed. Progeny nucleocapsids were detected in the nucleus at the same time. The envelopment of nucleocapsids occurred both at the nuclear membrane and at proliferating Golgi lamellae in the cytoplasm. Each site of envelopment is associated with the maturation of a characteristic, morphologically distinguishable virus particle. The assembly of HVA-73 resembled that of other oncogenic herpesviruses.

New ultrastructural findings within the nucleus of herpes simplex virus-infected cells are illustrated. The occurrence of bundles of tightly packed filaments during the late stages of the infectious process is described. These bundles were found in different areas of the nucleus and were not associated with any nuclear organelles. Employing different staining techniques and high-resolution autoradiography, they could be identified as DNA-containing nucleoproteins. These filaments may be interpreted as a special form of viral DNA accumulation within the nucleus. Changes of these structures toward a more recticular arrangement were observed as soon as the nucleoplasm disintegrated.

Cultures from various normal and neoplastic cell lines exfoliated vesicles with 5'-nucleotidase activity which reflected the ecto-enzyme activity of the parent monolayer culture. The ratio of 5'-nucleotidase to ATPase activity in the microvesicles indicated that cellular ecto-ATPase was conserved in the exfoliative process. Phospholipids of the microvesicles contained significantly increased amounts of sphingomyelin and total polyunsaturated fatty acids. It was concluded that the shedded vesicles constituted a select portion of the plasma membrane. Examination by electron microscopy showed the vesicles had an average diameter of 500 to 1000 nm and often contained a second population of vesicles about 40 nm in diameter. As much as 70% of the plasma membrane ecto-5'-nucleotidase activity of a culture was released into the medium over a 24-h period. Phosphoesterhydrolases from C-6 glioma or N-18 neuroblastoma microvesicles dephosphorylated cell surface constituents when in contact with monolayer cultures. Exfoliated membrane vesicles may serve a physiologic function; it is proposed that they be referred to as exosomes.

Cytoskeletal and adhesion characteristics of DL-ethionine (CAS: 67-21-0)-transformed rat liver epithelial cells (ETC) were compared with those of nontumorigenic, untreated cells of the same cell line both at the same passage level as ETC and at an early low passage level. ETC and high-passage-level cells (HPC) showed increased cell spreading and prominent actin stress fibers compared to low-passage-level cells (LPC). The number of adhesion plaques per unit cell area was higher for ETC than for LPC. At confluence, fibronectin expression was high for ETC, moderate for HPC, and low for LPC. The observed increases in cell spreading and in actin and fibronectin expression appeared to be associated with transformation of this cell line rather than being specific responses to ethionine treatment. This conclusion is suggested by the fact that HPC, which display preneoplastic markers, are similar in many respects to ETC.

60-70S RNA of avian myeloblastosis virus was spread with the Kleinschmidt method and examined in the electron microscope after being subjected to a variety of denaturing conditions. Extension of the molecules from a collapsed configuration was seen only under stringent denaturing conditions, resulting in molecules of 1-2 mum in length. Longer strands of these extremely fragile molecules cannot be obtained with the methods presently available.