bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the mechanism of action of 5‐aziridinyl‐2,4‐dinitrobenzamide (CB 1954), a selective inhibitor of the walker tumour
Authors: Connors T. A. , Melzack D. H. 
Published: February 2007

AbstractCB 1954, a monofunctional alkylating agent, has exceptional activity against the Walker carcinoma yet is inactive against a large number of other animal tumours. A line of the Walker tumour with acquired resistance to CB 1954 was cross‐resistant to Melphalan, implying a common mechanism of action, although other tumours highly sensitive to Melphalan were not affected by CB 1954. CB 1954 was also similar to Melphalan in its effects on DNA and RNA synthesis. No correlation was observed between binding of CB 1954 to the DNA of tumour cells and their sensitivity to it. Differences in response of the Walker tumour when incubated with Melphalan and CB 1954 suggest that the latter agent may have some features of an anti‐metabolite. In preliminary experiments, its selective anti‐tumour effect against the Walker carcinoma has been completely reversed by an intermediate in purine biosynthesis.
Studies on murine sarcoma virus: II. Detection of group‐specific antigens by immunofluorescence
Authors: Chuat Jean‐Claude , Lasquellec Françoise , L'hirondel Anne‐Marie , Boiron Michel 
Published: February 2007

AbstractThe group‐specific (GS) antigen of murine tumor viruses was demonstrated by immunofluorescence in mouse cells recently infected by mouse sarcoma virus, strain Moloney (MSV‐M), with the serum of rats carrying long‐transplanted MSV‐M tumors. GS antigen was detected 15 h post‐infection and was also present in various mouse and rat cell lines chronically infected with murine tumor viruses. The antigen was strictly localized in the cytoplasm of infected cells and was also found in mouse and rat cells chronically infected by members of the two major subgroups of murine tumor viruses. Further, the sera employed were shown to contain exclusively GS antibodies and the tumors used for immunization were found by several techniques to be free of virus envelope (V) antigens after a given number of passages in vivo. V antigens were visible only at the cell membrane and the time course of appearance of both GS and V antigens in recently infected cells was parallel. In contrast, GS antigen was not observed in two hamster tumor lines transformed by MSV‐M.
Recherche de particules virales dans des lignées cellulaires de hamster transformées par le virus de rous investigations on the presence of viral particles in rous transformed hamster cell lines
Authors: Gazzolo L. 
Published: February 2007

AbstractIn the framework of a study on the recovery of the Rous Sarcoma Virus (RSV) from transformed mammalian cells, nine Syrian hamster cell‐lines transformed by RSV were examined by electron microscopy. Six of these lines were obtained from BHK 21/Clone 13 cells transformed in vitro by RSV, either Schmidt‐Ruppin strain (SR‐RSV) or Bryan strain (B‐RSV), one of them being supertransformed by polyoma virus. Another line (RSH) was obtained from embryonic hamster cells transformed in vitro by SR‐RSV. Two lines resulted from in vivo experiments: SR/Cl2 was obtained from a SR‐RSV‐induced tumour in a Syrian hamster; and RS2‐TH2 represented an in vitro cultured tumour obtained in a Syrian hamster by the inoculation of RS2 cells transformed in vitro by SR‐RSV. All these lines had the group‐specific antigen (GS) and it was possible to rescue RSV from all lines except SR/Cl2 when they were cultivated in association with permissive chick cells.No C‐type virus particles could be observed either in the six lines transformed in vitro or in two lines (RSH and SR/Cl2) transformed in vitro. On the contrary, the line RS2‐TH2 contained C‐type particles, morphologically similar to murine leukemia virus, and probably representing a latent hamster virus. In line SR/Cl2, A‐type particles were found associated with mitochondria. The significance of the presence of these particles in this only non‐virogenic line is discussed. Finally, in all the hamster lines examined, R‐type particles were observed. They were more numerous in the in vivo transformed lines than in the in vitro transformed lines.
Some biophysical aspects of e‐b virus adsorption to the surfaces of three types of mammalian cells
Authors: Weiss L. , Horoszewicz J. S. 
Published: February 2007

AbstractThe electrokinetic properties of the surfaces of three types of cultured mammalian cells, in established lines, were studied to determine whether these properties could be correlated with adsorption of EB virus, as observed by electron microscopy and immunofluorescent techniques.As both viruses and cells carry a net negative surface charge, computations were made of the interactions between them using colloid theory. The results show that knowledge of various macroscopic surface parameters does not enable predictions to be made on whether viruses will adsorb or not. Modification of net surface charge by treatment of cells and viruses with neuraminidase, ribonuclease or with reagents reacting with amino‐groups, did not demonstrably affect adsorption, which was also apparently insensitive to calcium concentration.The results may be interpretable in terms of structural microheterogeneity of the surfaces of the cells and/or virus particles.
Effect of combination treatment with cyclophosphamide and isogeneic or allogeneic spleen and bone marrow cells in leukemic (l1210) mice
Authors: Vadlamudi S. , Padarathsingh M. , Bonmassar E. , Goldin A. 
Published: February 2007

AbstractGeneralized leukemia was observed on day 3 following intra‐peritoneal inoculation of leukemic (L1210) ascites cells in CDF1 mice. On day 3 after tumor implantation, residual viable leukemic cells were detected in the peritoneal cavities and spleens of leukemic mice 6 h following treatment with 180 mg/kg of cyclophosphamide. Mice receiving weekly intraperitoneal injections of X‐irradiated leukemic (L1210) cells for 6 weeks were resistant to a challenge of tumor cells. When incubated in vitro, spleen and bone marrow cells of immune mice were able to inactivate viable leukemic cells, as evidenced by failure of tumor growth in mice inoculated with these cells. Leukemic mice injected with immune spleen or bone‐marrow cells from isogeneic mice following treatment with cyclophosphamide survived a 60‐day observation period. In one such experiment 90‐day survivors were able to resist re‐inoculation of tumor cells. Leukemic (DBA/2) mice inoculated with allogeneic spleen cells following cyclophosphamide treatment survived for longer periods than mice injected with isogeneic spleen cells.
Immunofluorescent study of alpha‐foetoprotein (αfp) in liver and liver tumours. II. Localization of αfp in the tissues of patients with primary liver cancer (PLC)
Authors: Goussev A. I. , Engelhardt N. V. , Masseyeff R. , Camain R. , Basteris B. 
Published: February 2007

AbstractLocalization of αfp independent of the presence of serum was demonstrated only in a limited number of tumour cells in αfp‐positive hepatocellular carcinomas. These cells usually formed three‐dimensional groups with a definite tendency to localize near blood vessels and capillaries. Haematoxylin‐eosin staining did not reveal any morphological difference between αfp‐positive and ‐negative tumour cells.
Isoenzyme and protein profiles of normal, leukemic and fetal mouse tissues
Authors: Tyndall R. L. , Allen R. C. , Friedman E. , Moore D. J. 
Published: February 2007

AbstractElectrophoretic characterization of extracts from normal, leukemic and fetal mouse tissues indicated that infection with RLV results in the subsequent emergence of cells having profiles similar to fetal thymus and spleen tissues. Microdensitometric analyses showed diminution of prealbumin and haptoglobin esterase activity with concomitant predominance of postalbumin esterase activity in both fetal and leukemic thymus and spleen tissues. Both JLS V9 and JLS V6 infected cell cultures showed marked enhancement of postalbumin esterase activity. Leukemic and fetal thymus and spleen tissues also showed increased activity in LDH isoenzyme V, relative to the total LDH activity, compared to normal adult tissues. Increased relative activity in Band V LDH was also noted in infected V6 cells compared to uninfected cells. Increased amounts of proteins with electrophoretic mobilities similar to serum albumin and transferrin were evident in extracts of fetal and leukemic thymus and spleen tissues. Protein profiles of purified RLV showed a predominant band migrating similarly to serum albumin with minor bands migrating similarly to serum transferrin and haptoglobin.
Studies on friend virus‐induced viremia in lethally irradiated mice with or without hematopoietic repopulation
Authors: Rossi G. B. , de Harven E. , Haddad J. R. , Friend C. 
Published: February 2007

AbstractNo detectable viremia was recovered from supralethally irradiated mice which had been infected with Friend Leukemia Virus (FLV) although large amounts of virus were recovered from non‐irradiated control mice.When irradiated mice were repopulated with either spleen or bone‐marrow cells from syngeneic donors and then infected with FLV, viremia was readily detectable in these hosts, both by electron microscopy and by bioassay into susceptible mice. In similarly irradiated mice given thymus cells, however, no virus was detected by titration although extremely rare particles were observed in the plasma pellets examined by electron microscopy.These data indicate that the appearance of virus in the plasma depends upon the presence in the infected animals of FLV target cells, found primarily to be the hematopoietic components of both bone marrow and spleen.
Concomitant immunity in hamsters bearing syngeneic transplants of tumors induced by para‐adenovirus 7, simian adenovirus 7, or 9,10‐dimethylbenzanthracene
Authors: Lausch Robert N. , Rapp Fred 
Published: February 2007

AbstractStudies in an inbred line of hamsters have revealed that animals bearing tumor transplants reject a second graft of the same cells. This resistance was specific and was manifested against tumor cells induced by viruses (PARA‐adenovirus 7, simian adenovirus 7) or chemicals (9,10‐dimethylbenzanthracene). Studies designed to measure dose‐response revealed that tumor‐bearing hamsters were 10 to more than 100 times as refractory to challenge by a given cell line as were normal hamsters. Nevertheless, this immunity did not prevent continued growth of the primary transplant.
Extractable herpesvirus antigens from chickens with marek's disease
Authors: Ahmed Mumtaz , Leech Judith B. , Slattery Susan M. , Schidlovsky George 
Published: February 2007

AbstractMarek's disease herpesvirus (MDHV) antigens are demonstrable by indirect immunofluorescence and micro‐immunodiffusion tests in epithelial cells of feather follicles (FF) of chickens infected with GA strain of MDHV; but lymphoid tumor cells are devoid of virus particles and virus‐associated antigens. The antigens extracted from virus‐containing epithelial cells growing in vivo or in vitro were found to be of a similar nature. Electron microscopy showed that antibody‐positive chicken sera caused specific coating of MDHV particles extracted from feather follicular cells.
Decrease in tumor‐producing capacity of mouse cell lines following infection with mouse leukemia viruses
Authors: Barbieri D. , Belehradek J. , Barski G. 
Published: February 2007

AbstractTwo neoplastic cell strains derived from the C57BL/6 mice, P4bis originating from normal adult lung tissue “spontaneously” transformed in vitro, and TBLC2 developed from a methylcholanthrene‐induced sarcoma, were both infected in vitro with Rauscher leukemia virus. Consecutive to this infection, the tumor‐producing capacity of these cells, which continued to multiply normally in vitro, dropped considerably when checked in syngeneic mice. This was evidenced by a dramatic decrease of takes and a significant prolongation of latency period. The high leukemogenic RRL+ and the low leukemogenic RCL− virus variants were equally efficient in infecting cells in vitro and producing a decrease of their tumorigenic potential in vivo. This decrease coincided with the massive appearance in the cells and culture supernatant of C‐type particles and of a new surface antigen reacting specifically in the immunofluorescence test with anti‐Rauscher virus serum. The specific immunological nature of decreased tumorigenicity was confirmed by the fact that the rejection of the virus‐infected cells could be prevented by total irradiation of intact recipient animals, whereas animals preimmunized and later irradiated continued to reject the infected cells. On the other hand, the rare tumors which appeared in non‐irradiated adults after a long latency period were composed of virus‐free cells whereas cells from tumors obtained by inoculation of new‐born animals regularly contained the virus and were rejected when grafted on normal adults.In another series of experiments, in P4bis cell cultures, subjected in vitro to the action of methylcholanthrene for several months, the appearance of C‐type particles and of a new cell‐surface antigen reacting specifically in the immunofluorescence test with anti‐Gross leukemia serum, was observed. The untreated control cultures remained negative for C particles and antigen. The appearance of this chronic C‐type virus infection coincided, here again, with a considerable decrease in tumor‐producing capacity of the P4bis cells as checked in syngeneic mice.The reported results are discussed in the context of the possible role played by chronic infections, especially by widely spread non‐pathogenic variants of leukemia viruses, in the “heterogenization” of tumor cells contributing to their rejection triggered by an immune reaction of the host.
Characteristics of established myeloma and lymphoblastoid cell lines derived from an e myeloma patient: A comparative study
Authors: Nilsson Kenneth 
Published: February 2007

AbstractThe in vitro characteristics of two types of cell lines established from bone marrow and peripheral blood of an E myeloma patient have been compared. Both types, one with a lymphoblast morphology and the other with plasma cell/plasmablast morphology, secreted monoclonal immunoglobulins in vitro. The former produced IgGK while the latter synthesized the IgEL myeloma protein, which in a previous report was shown to be identical with the myeloma protein in vivo.The myeloma cells were difficult to establish and more stringent in their in vitro requirements than the lymphoblastoid cells. Myeloma cells could only grow in the presence of feeder cells or medium harvested from such cells, while lymphoblasts were capable of independent growth in standard media. The lymphoblastoid line was principally similar to those obtainable from normal lymph nodes (Nilsson et al., 1968; Nilsson, 1971a) and is therefore regarded as being of non‐neoplastic origin. It is thus possible to obtain permanent immunoglobulin‐secreting lines of non‐neoplastic origin as well as myeloma lines of neoplastic origin from patients with myelomatosis. The dynamic and static morphology of the former most closely correspond to the appearance described for lymphoblasts or “immunoblasts”,i.e. lymphocytes stimulated by phyto‐hemagglutinin, while myeloma cells resemble plasma cells of varying maturity. The reasons for the morphologic differences are unknown, but they were sufficiently distinctive to permit unequivocal distinction between the two types of lines.
Mechanism of resistance of yoshida sarcoma to nitrogen mustard
Authors: Inaba Makoto , Sakurai Yoshio 
Published: February 2007

AbstractUptake and binding of methyl‐bis(2‐chloroethyl)amine hydrochloride (HN2) to the cells of Yoshida sarcoma during their acquisition of resistance to this drug was investigated. With the increase of resistance index, drug uptake by the cells decreased. A good parallelism was found between resistance index and binding rate of the drug with cellular constituents when the intact cells were kept contacted in vitro with the drug in an incubation medium. When the cells were homogenized before contact with the drug, there was no difference in binding rate of the drug between sensitive and resistant cell lines. Suppression of cell membrane transport seemed to play a role in the acquisition of resistance by the cells.
Detection of tumor‐specific cell surface antigen of simian virus 40‐induced tumors by the isotopic antiglobulin technique
Authors: Ting Chou‐Chik , Herberman Ronald B. 
Published: February 2007

AbstractSimian virus 40 (SV40) tumor‐specific cell surface antigen (TSSA) was assayed by the isotopic antiglobulin technique. Antisera were produced by immunization of A/LN mice with syngeneic SV40‐induced tumor designated SV‐A/LN. Positive reactions were only obtained with SV40‐transformed mouse or hamster cells which possessed both SV40 TSTA (tumor‐specific transplantation antigen) and T antigen. Negative reactions were obtained with untransformed cells or non‐SV40 tumors. The T antigen‐negative cells (“T‐ S+” by Tevethia et al., 1968), which lack TSTA and viral RNA or viral DNA, also gave negative reactions. Absorption experiments further confirmed the specificity. These results showed that the SV40 TSSA detected by the isotopic antiglobulin technique was virus‐specific, and was correlated with the expression of TSTA.
Ultrastructure of giant cells in tumours induced in golden hamsters by murine sarcoma virus‐harvey
Authors: Hallowes R. C. , Chesterman F. C. 
Published: February 2007

AbstractTumours induced in golden hamsters by murine sarcoma virus‐Harvey were studied in four situations: in subcutaneous tissue, on paws or distal ends of limbs, in muscle and in association with bone destruction. Most of the tumours contained multinucleate giant cells. In subcutaneous tumours, a “filament ous” type of giant cell was seen with long filamentous cell processes and bizarre‐shaped nuclei. Also present was an “interlocking” type which had short cell processes that interlocked with those of surrounding uninuclear cells. The groups of cells formed in this way resembled a granuloma. Degenerating multinucleate sarcolemmal cells were seen at the edge of muscle tumours and “vegetative” muscle cells were also present. A “pleomorphic” type of giant cell was seen in paw, muscle and bone‐eroding tumours. This was a multinucleate cell differentiated to respond to cellular damage caused by tumour infiltration. Groups of cells resembling those seen in granulomas were also present in these tumours.
Epidemiologic evidence for multi‐stage theory of carcinogenesis
Authors: Hakama Matti 
Published: February 2007

AbstractA multi‐stage model of carcinogenesis is proposed assuming time homogeneous transition intensities from stage to stage. The model shows a fairly close agreement with the observed age incidence curves, not only for epithelial tumors, but also for tumors showing a more irregular age pattern. The model is applied to throw light on the mechanisms of carcinogenesis. Selected primary sites are considered and it is proposed that tumors of peripheral nerves in children and young adults are a result of a single change or hit, acute leukemia in children is probably a two‐hit disease, whereas most tumors of epithelial origin require several changes. Tumors with a bimodal incidence curve, like Hodgkin's disease and breast cancer, are likely to consist of two entities.It is stressed that the assumption of constant transition intensities may not be true, especially in regard to tumors with conceivably long periods of exposure.Different incidence patterns have required different interpretations on the mechanisms of carcinogenesis. The model presented in this paper provides a synthetic explanation for the genesis of different types of tumors with apparently different shapes in the age‐specific incidence curves.
An epidemiological analysis of cancer vaccines
Authors: Higginson John , de‐Thé Guy , Geser Anton , Day Nicholas 
Published: February 2007

AbstractThe logistic and epidemiological problems associated with the development of an effective virus vaccine for cancer are discussed. It is shown that if human tumours are caused by viruses with short latent periods, it will be possible to test the effectiveness and safety of the vaccine without following up unrealistically large control and experimental groups.On the other hand, if the viruses concerned are non‐specific, and only a small proportion of the infected population develops cancer after a long and varied latent period, it will be very difficult to test the effectiveness of such vaccines in present society. This is due to the large number of individuals who would have to be followed up for prolonged periods.
Enhanced growth of primary moloney virus‐induced sarcomas in mice
Authors: Pierce George E. 
Published: February 2007

AbstractPre‐treatment of BALB/c mice with an intraperitoneal injection of heat‐inactivated serum obtained from BALB/c mice with progressively growing Moloney‐virus‐induced sarcomas (“progressor” mice) shortens the latent period and increases the growth rate and maximum size of primary sarcomas induced in these mice by Moloney virus inoculation 24 h after the serum injection.Pre‐treatment with heat‐inactivated serum obtained from BALB/c mice after the complete regression of Moloney sarcomas (“regressor” mice) decreases the growth of subsequently induced Moloney sarcomas in mice so treated.These observations are discussed in relation to the recent findings of Hellström and Hellström (1969, 1970) that serum fiom “progressor” mice blocks the cytotoxic effects of specifically immune lymph‐node cells when tested against target Moloney sarcoma cells in vitro arid that serum from “regressor” mice competes with or abrogates the blocking effect of “progressor” serum.
The mechanisms of action of anti‐tumour polysaccharides. I. The effects of antilymphocyte serum on the anti‐tumour activity of lentinan
Authors: Maeda Yukiko Y. , Hamuro Junji , Chihara Goro 
Published: February 2007

AbstractMechanisms of the regression of transplantated tumours in mice caused by lentinan, an anti‐tumour polysaccharide, were examined. 1) Lentinan showed a marked anti‐tumour effect when the animal was pretreated, starting 12 days before tumour inoculation. 2) The anti‐tumour effect of lentinan was blocked by injection of anti‐lymphocyte serum from 24 h after tumour transplantation. Lymphoid cells attacked by this serum apparently play an important role in tumour regression induced by lentinan. 3) Considering the selective actions of anti‐lymphocyte serum as an immunosuppressor, one of the mechanisms responsible for the anti‐tumour effect of lentinan may be the stimulation of cell‐mediated responses. 4) Humoral antibodies against lentinan do not seem to participate in tumour regression.
Study of the in vivo fixation of antibodies on tumors provoked in hamsters by injection of SV40‐transformed cells (TSV5Cl2)
Authors: Sobczak E. , Cyr Ch. de Vaux Saint 
Published: February 2007

AbstractLarge particle fraction obtained by the technique of Sjögren and Motet (1969) can be treated at acid pH, to elute immunoglobulins from hamster tumors induced by injection of SV‐40 transformed fibroblasts (TSV5Cl2). The eluate contains IgG27S, as well as two fragments having molecular weights of about 67,000; one of these, Fc, migrates in the β region, and the other, F(ab), migrates in the slow y region. This eluate, tested on TSV5Cl2in culture, contains some cytotoxic antibodies and antibodies against T antigen and cytoplasmic antigen.