bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the loss of growth inhibition in cells infected with Rous sarcoma virus
Authors: Weiss Robin 
Published: February 2007

AbstractThe loss of density‐dependent and anchorage‐dependent growth was studied in cells infected with RSV. Transformed cells, but not uninfected cells, will proliferate in soft gel suspension and amongst crowded normal cells. A large proportion of cells freshly infected with RSV acquired the capacity to proliferate in soft agar suspension even when placed in suspension immediately after infection.Cell transformation and viral replication were inhibited by plating freshly infected cells on to crowded mouse embryo cells or 3T3 cells. The inhibition of cell transformation depended on close proximity to crowded mouse cells spread on a solid substratum. Cells became released from density‐dependent transformation within 12 h following infection. The change in proliferative behaviour of transformed cells was not influenced by the quantity or envelope properties of virus released from the cell surface. Pre‐infection with RAV1 did not affect density‐dependent cell transformation by RSV.Freshly infected cells held in the inhibited state for 6 days were able to transform when replated to sparse conditions. It was concluded that cell transformation depended on cell proliferation but that infection with RSV could not initiate the cell division cycle in crowded monolayers.
Serum alpha‐fetoprotein and variant alkaline phosphatase in human hepatocellular carcinoma
Authors: Poertugal M. L. , Azevedo M. S. , Manso Carlos 
Published: February 2007

AbstractAlpha‐fetoprotein and variant alkaline phosphatase were studied in a group of patients with hepatoma. The incidence of positive alpha‐fetoprotein was 67.6% in confirmed cases. Variant alkaline phosphatase was present only in patients with positive fetoprotein test, and it appeared in only 28.6% of the cases.
Studies on the infectivity and cytopathology of epstein‐barr virus in human lymphoblastoid cells
Authors: Durr F. E. , Monroe J. H. , Schmitter R. , Traul K. A. , Hirshaut Y. 
Published: February 2007

AbstractThe infectivity of EB virus recovered from cultures of P‐3J and the HR1K clone of this cell line has been demonstrated in established lymphoblastoid cell lines derived from healthy human donors and from patients with neoplastic disease. Filtered virus concentrates induced cell alterations similar to those produced by other members of the herpes group of viruses. Cell responses observed were: 1) an acute cytopathic effect evident within 16–72 h and characterized by cell swelling, polykaryocyte formation and progressive degeneration, and 2) a less severe CPE with minimal cell swelling and degeneration followed by either the establishment of a carrier culture or more often a culture in which the virus eventually disappeared. Characteristic non‐enveloped herpes‐virus‐type particles were seen in the cell nucleus as early as 16 hours post exposure to virus and, subsequently, enveloped virions were found in the cytoplasm. A non‐productive or abortive infection of the lymphoblastoid cells was indicated by the higher incidence of cells showing viral antigen by immunofluorescence, than the presence of virus particles. The infectivity of EBV was neutralized by human sera containing antibodies reactive with the viral envelope.
Binding of dimethylaminoazobenzene metabolites to DNA and proteins. I. in vitro studies on a microsomal dependent system
Authors: Meunier Michèle , Chauveau Jean 
Published: February 2007

AbstractIncubating dimethylaminoazobenzene [aniline ring (U)14 C] (DAB), purified thymus DNA and rat liver microsomes led to a covalent binding of radioactivity to DNA and proteins, which implied the presence of bound DAB metabolites.This binding required an enzymatic activation. We studied some characteristics of the enzymatic process, i.e. NADPH requirement, effect of pH, effect of various concentrations of microsomes and DNA, induction by 3‐methylcholanthrene.This in vitro system is discussed in view of its validity for studying interactions between the carcinogenic azodyes and the cellular constituents.
Demonstration by colony inhibition methods of cellular and humoral immune reactions to tumour‐specific antigens associated with aminoazo‐dye‐induced rat hepatomas
Authors: Baldwin R. W. , Embleton M. J. 
Published: February 2007

AbstractCellular and humoral immune reactions against tumour‐specific antigens on aminoazo‐dye‐induced rat hepatomas were demonstrated in vitro by the colony inhibition technique. Lymph‐node cells from syngeneic rats immunized against individual hepatomas inhibited colony formation by cells of the immunizing tumour compared with the effects of normal lymph‐node cells. Also immune lymph‐node cells were not inhibitory to hepatomas other than the one used for immunization, reflecting the individual specificity of the antigens on these hepatomas. Serum‐mediated inhibition of colony formation by rat hepatoma cells, in the presence of complement, was also demonstrated and these reactions were similarly directed against cells of the immunizing tumour. This specificity of colony inhibition by immune lymph‐node cells and serum further amplifies the evidence for the individually distinct antigenicity of these hepatomas already revealed by transplantation and immunofluorescence tests.
Differences in the manifestation of virus‐specific surface antigen between cells transformed by sv40 and uv‐irradiated sv40
Authors: Klietmann W. , Seemayer N. 
Published: February 2007

AbstractMarked differences in the manifestation of SV40‐specific surface (S‐) antigen were found between hamster cell lines transformed in vitro and in vivo by SV40 and UV‐irradiated or photodynamically inactivated SV40. In the mixed hemagglutination reaction (MHA) cell lines induced by non‐irradiated SV40 yielded positive results when tested against specific antisera up to dilutions of 1:1280. In comparison, cell lines induced by inactivated SV40 only showed positive reactions in the MHA‐test in dilutions up to 1:80 or 1:160 respectively. The demonstration of small quantities of SV40‐specific S‐antigen in cell lines transformed by inactivated SV40 could only be achieved by use of hyperimmune sera produced by a special immunization procedure. However, if these cells were tested in the MHA reaction against anti‐S‐sera, produced according to conventional methods described in the literature, they yielded negative results. All cell lines with diminished quantities of demonstrable S‐antigen caused malignant tumors when inoculated into adult hamsters. The capacity of UV‐irradiated SV40 to induce a specific transplantation resistance in adult Syrian hamsters was investigated. The irradiated virus induced a markedly reduced transplantation resistance.
The development of chick‐embryo‐lethal‐orphan (CELO) virus T and V antigens in lytically infected chick kidney cells
Authors: Anderson Jeffrey , McCormick Kenneth J. , Stenback Wayne A. , Trentin John J. 
Published: February 2007

AbstractThe sequential development of the CELO‐specific T and virion antigens was studied in lytically infected chick kidney cells using the indirect immunofluorescence technique. The T antigen was detected 6 hours after infection, and rapidly increased until a peak was reached at 20–24 h. The V antigen could not be detected until 20 h after infection. The V antigen, but not the T antigen, was inhibited by cytosine arabinoside. Both antigens were inhibited by cycloheximide. After storage in liquid nitrogen for 3 weeks, the T antigen in fixed cells could not be detected by indirect immunofluorescence tests.
Studies on the mechanisms of invasion in cancer. II. In vivo effects of a factor chemotactic for cancer cells
Authors: Ozaki Teruhisa , Yoshida Kenshi , Ushijima Kenichiro , Hayashi Hideo 
Published: February 2007

AbstractA substance chemotactic for tumor cells was isolated from some tumor tissues of animal and human origin and highly purified. It induced an extravascular emigration of circulating tumor cells on experimental injection, but no emigration of polymorphonuclear leukocytes. The emigrated tumor cells proliferated in the extravascular tissue and invaded the surrounding tissues, and a metastatic secondary tumor was formed. This material had no activity to increase vascular permeability. Permeability factors, isolated from tumor tissues, histamine and bradykinin were ineffective for tumor‐cell emigration. A factor chemotactic for polymorphonuclear leukocytes, isolated from inflamed sites, induced an emigration of the cells on experimental injection, but no emigration of tumor cells. These observations suggested that the cancer cell chemotactic factor might be associated with malignant invasion.
Ultraviolet inactivation of murine leukemia and sarcoma viruses
Authors: Yoshikura H. 
Published: February 2007

AbstractThe ultraviolet (UV) sensitivity of Friend leukemia virus and a murine sarcoma virus (MSV) was determined. The inactivation dose D10 was 2,000 to 3,000 ergs/mm2 for both. This value is close to the one obtained with Rous sarcoma virus, 3,000 ergs/mm2 (Goldé et al., 1961). MSV produced by the cells incubated in 5‐fluorouracil (5 × 10−3 M) was significantly more UV sensitive than control MSV, suggesting the sensitization of the viral nucleic acid by the base analogue.The virus surviving UV irradiation showed a prolonged latent period, but it was due to the interference of the inactivated virions with the normal growth of surviving virions.When UV‐irradiated MSV was titrated on the cells previously irradiated with UV, the slope of the inactivation curve was steeper than when the virus was titrated on the normal cells. This may suggest the complementation of the UV‐damaged viral genome by the corresponding homologous host genome.
Mammary tumors, plaques, and hyperplastic alveolar nodules in various combinations of mouse inbred strains and the different lines of the mammary tumor virus
Authors: Heston W. E. , Vlahakis G. 
Published: February 2007

AbstractThe following strains have been bred and developed for mammary tumor studies in this laboratory; C3H, C3HfB, C3HfDD, C3H‐Avy, C3H‐AvyfB, DD, DDfB, DDfC3H, BALB/c, BALB/cfDD, BALB/cfC3H, A (High), A (Low), AfB, and C57BL. Data are presented on mammary tumor incidence and age, occurrence of plaques, and occurrence of hyperplastic nodules. C3H‐Avy is our highest mammary tumor strain, whereas C57BL is the most resistant. A complete range of mammary tumor incidences and average ages depending upon the strain of mouse and line of virus is found in the other strains. The occurrence of mammary tumors in strains fostered on C57BL ranges from an incidence of 90% at an average age of 15 months in C3H‐AvyfB, although there is no evidence of any milk‐transmitted virus, to 1.3% at 16.5 months in AfB. We continue to find an incidence of 20% at 17 months in BALB/c although we have no conclusive evidence of the virus. C3H virus has a greater potency than DD virus. Plaques are the result of DD or BALB/c genotype and DD virus but not of C3H or A genotype or of C3H or A virus. Hyperplastic nodules appear in all strains that develop mammary tumors, the age at which they appear depending upon the mouse strain and line of virus. These data form the foundation for other studies with these strains. The strains are now available to other investigators.
Stimulation of liver dna synthesis by a factor from ascites tumor 6c3hed
Authors: Yarbro J. W. 
Published: February 2007

AbstractC3H mice inoculated with 6C3HED ascites tumor show a gradual increase in the incorporation of 32P into liver DNA. Cell‐free supernatant fluid from this tumor has the capacity to stimulate increased incorporation of 32P and 3H‐labelled thymidine into liver DNA of mice not bearing the tumor. This liver‐stimulating activity (LSA) was destroyed by heating to 60° C for 30 min and by pronase but not by RNase or DNase. The time of maximum stimulation of liver DNA synthesis was on the 4th day after injection of LSA. A 70‐fold purification of LSA was accomplished using sephadex chromatography. It is suggested that LSA is the factor responsible for the increased liver DNA synthesis seen in tumor‐bearing animals, but the mechanism of this action has yet to be explained.
Some effects of neuraminidase on the in vitro interactions between spleen and mastocytoma (P815) cells
Authors: Weiss L. , Cudney T. L. 
Published: February 2007

AbstractA recently advanced generalization is that a sialomucin coat surrounding tumour cells protects them from immunological surveillance. We have therefore studied the effects of neuraminidase (sialidase) on the immunolysis of P815 mastocytoma cells by sensitized spleen cells, in vitro, to test this hypothesis. In a very sensitive system in which immunolysis was quantitated by measurements of the release of 51Cr from labelled P815 cells, neuraminidase treatment of the target cells did not demonstrably make them more susceptible to attack by spleen cells. Killing proceeded in spite of a substantial contribution of sialic acid moieties to the net negative surface charge of the untreated P815 cells, and was not enhanced by enzymatic removal of substantial amounts of their bound surface sialic acids, as determined by cell electrophoresis. Thus, the generalization cannot be substantiated by our experiments. An interesting positive finding was that neuraminidase treatment of the killer, spleen cell population, enhances the 51Cr‐release from their targets.
Studies of carcino‐fetal proteins: Physical and chemical properties of human α‐fetoprotein
Authors: Ruoslahti Erkki , Seppälä Markku 
Published: February 2007

AbstractTo obtain information on the relationship between a carcino‐fetal protein, α‐fetoprotein, fetal proteins from other species and other human serum proteins including the fetoprotein in patients with hepatocellular cancer, α‐fetoprotein was purified and characterized from the serum of human fetuses. The protein is composed of a single polypeptide chain. A molecular weight of 70,000 was obtained by gel electrophoresis in the presence of SDS and by gel filtration. The isoelectric point of α‐fetoprotein was found to be 4.75. It contains 4.3% carbohydrate with 2 moles of sialic acid per mole of protein. The amino acid composition of α‐fetoprotein was determined.
Blocking of cell‐mediated tumor immunity by sera from patients with growing neoplasms
Authors: Hellström Ingegerd , Sjögren Hans Olov , Warner Glenn , Hellström Karl Erik 
Published: February 2007

AbstractBlood lymphocytes from tumor patients can specifically destroy cultivated neoplastic cells of the same histological origin as the tumors of the lymphocyte donors, irrespective of whether or not the donors have symptoms of growing tumor.The purpose of the present study was to investigate whether sera from tumor patients could block the cytotoxic effect of lymphocytes immune to the specific antigens of the respective neoplasms. A wide variety of tumors were included in the tests, namely malignant melanomas, carcinomas of the colon, breast, ovary, endometrium, kidney, cervix uteri, lung, larynx, bladder, Fallopian tube, lip, seminomas and sarcomas.Sera from 67 out of 81 patients with growing neoplasms were found to block the cytotoxic effect of specifically immune lymphocytes. A blocking effect was seen both when the tumor cells, lymphocytes and sera were derived from the same patients and when the lymphocytes and sera were taken from different donors who had the same types of tumor as the target cells. No blocking was seen when the same sera were tested on tumors of histological types other than those of the respective serum donors.A blocking serum activity was seen in only three of 19 patients who were symptomfree after tumor therapy. The findings thus suggest that there is a correlation between tumor growth in vivo and the presence of a blocking serum activity in vitro.
Epithelial outgrowths from lung tissue following intrapleural injection of asbestos dust in experimental animals
Authors: Davis J. M. G. 
Published: February 2007

AbstractAfter the intrapleural injection of asbestos dust in experimental animals, granulomas were produced and large areas of the pleural surface became thickened with fibrous tissue. In guinea‐pigs injected with chrysotile dust, alveolar epithelial cells often migrated through the lung surface and were found lining spaces in the areas of pleural fibrosis. Initially these cells exhibited the exact structure of the surfactin‐secreting type of alveolar cell, but later many of the cells lost the surfactin granules from their cytoplasm and became ciliated. In some animals cystic formation occurred in the lung tissue and groups of cysts grew out from the lung to invade the areas of pleural fibrosis. These cysts were also lined with surfactin‐secreting alveolar cells. The possible association of these epithelial outgrowths and the well‐known difficulties of diagnosing pleural mesotheliomas are discussed.
Evidence of formation of N‐methyl‐N‐nitrosourea in rats given n‐methylurea and sodium nitrite
Authors: Montesano Ruggero , Magee P. N. 
Published: February 2007

AbstractN[14C]‐methylurea and sodium nitrite were administered simultaneously to rats by stomach tube in order to demonstrate methylation of the nucleic acids due to the formation in the stomach of the corresponding nitrosamide, N[14C]‐methyl‐N‐nitrosourea. The ion‐exchange chromatograms of the hydrolysates of stomach, liver and small intestine nucleic acids show a radioactive peak corresponding to the altered base 7‐methylguanine in the rat receiving N[14C]‐methylurea and sodium nitrite. No evidence of 7‐methyl‐guanine was obtained when N[14C]‐methylurea was administered alone. These findings are interpreted as indicating that the highly potent carcinogen N‐methyl‐N‐nitrosourea is formed in the stomach as a result of the nitrosation of the corresponding secondary amide and absorbed into the circulation of the rat. The possible consequences of the in vivo formation of carcinogenic N‐nitroso compounds in the aetiology of cancer are discussed.
Assessment of risk patterns in cancer of the cervix: A comparison between greater Bombay and Western countries
Authors: Jussawalla D. J. , Deshpande V. A. , Standfast S. J. 
Published: February 2007

AbstractIn order to identify the high‐risk groups in the community, a retrospective study of 503 women with histologically proved invasive carcinoma of the uterine cervix was undertaken and the results were compared with a similar appraisal of an equal number of controls closely matched for age, religion and income, in order to examine certain risk factors suspected of being of aetiological importance in patients with cervical cancer. We have sought to estimate the effects of parity, and of age at first marriage, first delivery and last delivery. The highest risk was observed in women who had undergone several pregnancies early in life. It is interesting to note that multiparity was one of the important risk factors in Bombay women, in contrast with the situation reported in Western countries.
Further manifestations of abortive transformation of bhk 21 cells by polyoma virus
Authors: Taylor‐Papadimitriou Joyce , Stoker M. G. P. , Riddle P. 
Published: February 2007

AbstractAbortive transformation of layer cultures of BHK 21 cells by polyoma virus has been studied using serum‐depleted medium. High doses of partially purified infectious virus, in the absence of serum, stimulate the majority of the cells to synthesize DNA while empty capsids do not. The onset of DNA synthesis occurs approximately 28 h after infection, and in medium containing 0.8% γ‐depleted serum, can be followed by one round of mitoses. A temporary loss of oriented arrangement of cells is also observed commencing 25 to 30 h after infection. Abortively transformed cells resemble stably transformed lines of BHK 21 cells in their requirements for the factors in serum operative in the control of growth.
Cellular immunity to nephroblastoma
Authors: Diehl V. , Jereb Berta , Stjernswärd J. , O'toole Carol , Åhström L. 
Published: February 2007

AbstractLymphocytes from 24 patients with nephroblastoma and 24 controls have been tested for tumor‐related cytotoxicity in vitro. The micro‐plate technique has been applied in 26 tests and the cytotoxic plaque test in eight.In 10 out of 24 nephroblastoma patients with two autochthonous and eight allogeneic combinations, tumor‐related cell‐mediated cytotoxicity has been found. Lymphocytes from control subjects were less cytotoxic against nephroblastoma cells and affected tumor and control cells to the same degree. Lymphocytes from patients treated for primary tumors showed tumor‐destructive reactions more often than those from patients treated for disseminated disease.
Effect of antithymocytic serum on viral leukemia, erythroblastosis, and sarcoma in mice
Authors: Varet B. , Levy J. P. , Leclerc J. C. , Kourilsky F. M. 
Published: February 2007

AbstractThe effect of heterologous antilymphocytic sera (ALS) on the growth of a number of virus‐induced erythroblastoses, leukemias and sarcomas in mice has been investigated. Erythroblastosis is markedly stimulated by ALS, given either before or several days after virus inoculation. The stimulating effect of ALS administration on the outgrowth of murine sarcoma is strong if ALS is given before MSV inoculation, and weak when given no more than 24 h after the virus. Conversely, a stimulating effect of ALS on the development of leukemias was barely detectable, suggesting that immune reactions are less effective in the studied leukemia than in sarcoma and erythroblastic disease. An erythroblastic disease similar to the Friend‐Rauscher virus induced splenomegaly was observed after inoculation of Moloney leukemia virus or sarcoma virus and ALS.
Electron microscopic detection of transforming viruses induced by cell association. I. The SV40 model
Authors: Menezes José 
Published: February 2007

AbstractThis paper describes a study on the application of electron microscopy for rapid detection of SV40 particles rescued from transformed cells by co‐cultivation or fusion of these cells with either permissive or naturally insusceptible cells and discusses the utility of the electron microscope as a rapid means for the detection of virus recovered from human or animal tumors, as well as from other diseases where viral etiology seems the most probable.
Lysosomes of rat liver and dab carcinogenesis
Authors: Takano Tatsuya , Kato Nobuo , Kunimoto‐Miyata Setsuko , Goto Sataro , Ohkuma Shoji , Mizuno Den'ichi , Kitagawa Tomoyuki , Yokoyama Takeshi 
Published: February 2007

AbstractThe relationship between DAB carcinogenesis and changes of lysosomes in rat liver was investigated. After 40 days of treatment with DAB, nodules and an abnormal cell population, containing small, large and degenerative cells, appeared. Corresponding to these changes, the S/P ratio of lysosomal enzymes such as acid RNase and β‐glucuronidase increased to two or three times the normal value. These alterations were considered along with some histochemical observations on β‐glucuronidase. A possible participation of these lysosomal enzymes in carcinogenesis is discussed.