bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the persistence of tumour initiation and the acceleration of tumour progression in mouse skin tumorigenesis
Authors: Roe F. J. C. , Carter R. L. , Mitchley B. C. V. , Peto R. , Hecker E. 
Published: February 2007

AbstractEvidence has been obtained for the reversibility of initiation of carcinogenesis as evoked by 100 μ 7,12‐dimethylbenz (a)anthracene (DMBA) applied to the skin of Swiss mice. Mice exposed to twice‐weekly applications of a phorbol ester, TPA, for 15 weeks developed multiple papillomas when treatment was started 3 weeks after tumour initiation with DMBA, but very few when the interval was 50 weeks. This finding is not necessarily at variance with the postulate of the irreversibility of formation of “latent tumour cells” by subcarcinogenic doses of DMBA.Intraperitoneal injections of urethane increased the risk of development of malignant skin tumours by mice bearing multiple papillomas as a result of previous treatment with 100 μMg DMBA and TPA as compared with intraperitoneal injections of distilled water. This finding may allow a more clear‐cut experimental definition of the stages in the process of tumour progression in mouse skin tumorigenesis.
Specific killing of tumor cells In vitro in the presence of normal lymphoid cells and sera from hosts immune to the tumor antigens
Authors: Pollack Sylvia , Heppner Gloria , Brawn R. James , Nelson Karen 
Published: February 2007

AbstractEvidence is presented for specific in vitro killing of neoplastic target cells in the presence of non‐sensitized lymphoid cells and heat decomplemented sera from mice bearing the respective neoplasms or whose tumors had been removed. Such an effect was observed with sera from mice bearing Moloney sarcoma virus (MSV)‐induced and 3‐methylcholanthrene (MCA)‐induced sarcomas, and from mice whose mammary tumor virus (MTV)‐induced adenocarcinomas had been removed. Neoplastic target cell death was not characteristically mediated by such sera alone or by normal lymphoid cells in the presence of serum from animals bearing some other tumor, but appeared to be a specific, synergistically produced cytotoxicity.
Properties of an sv40‐transformed african green monkey kidney (bsc‐1) cell line
Authors: Suarez H. G. , Bourali M.‐F. , Wicker R. , Estrade S. , Cassingena R. 
Published: February 2007

AbstractAn SV40‐transformed BSC‐1 cell line (BSC‐SV Cl 1.1), that had been cloned twice under SV40 antiserum, sporadically produced small amounts of SV‐40 virus spontaneously. Most of the cells contained a defective virus genome, while some contained a non‐defective virus genome which was not readily reactivated. The BSC‐SV Cl 1.1 cell line was susceptible to superinfection by SV40 DNA and virus, but its capacity to support SV40 replication was consistently lower than that of infected BSC‐1 cells. This appeared to be a property of the individual cells. The ability of individual cells to initiate SV40 replication upon superinfection may depend on the multiplicity of infection. Following fusion with SV40‐transformed hamster cells containing a nondefective virus genome (TSV‐5 Cl 2), the BSC‐SV Cl 1.1 cells activated the production of SV40 virions in TSV‐5 Cl2 cells. The yield of virus depended on the cell line or subclone used.
Absence of circulating antibodies to carcinoembryonic antigen in patients with gastrointestinal malignancies
Authors: Gerfo P. Lo , Herter F. P. , Bennett S. J. 
Published: February 2007

AbstractThe zirconyl phosphate gel assay (Z‐gel) was used to assay sera of 265 patients for humoral activity against carcinoembryonic antigen (CEA). Included in the patients tested were 110 with non‐metastatic colon carcinoma, 122 with other gastrointestinal, breast and pulmonary neoplasms, 20 pregnant women and 13 healthy volunteers. Twenty‐five of the patients were also analyzed with molecular filtration column chromatography. Antibody activity directed against CEA could not be detected with either technique. Possible explanations for these results are discussed.
Metabolism and macromolecular binding of dibenz(a,c)anthracene and dibenz(a,h)anthracene by mouse embryo cells in culture
Authors: Duncan Margaret E. , Brookes P. 
Published: February 2007

AbstractThe metabolism and consequent macromolecular binding of dibenz(a,c)anthracene and dibenz(a,h) anthracene by mouse embryo cells in culture was compared at approximately equal, low doses of hydrocarbon in the medium. Both hydrocarbons were metabolized more slowly than other hydrocarbons tested previously. The binding index (the extent of reaction of the hydrocarbon with the particular macromolecule resulting from metabolism of 1 mμMmole of hydrocarbon per ml of medium to which the cells were exposed) to DNA and RNA was low for the non‐carcinogenic dibenz(a,c)anthracene and at least 10 times higher for the carcinogenic dibenz(a,h) anthracene.
The effect of transplacental administration of ddt on organ cultures of foetal mouse lung tissue
Authors: Shabad L. M. , Kolesnichenko T. S. , Nikonova T. V. 
Published: February 2007

AbstractRecent data pointing to a possible oncogenic action of DDT‐one of the most widely used pesticides‐have led the World Health Organization to undertake, through the International Agency for Research on Cancer in Lyons, a collective international study on this compound. Organ cultures of foetal lung tissue from strain A mice exposed to DDT through the transplacental route showed intensive growth as compared to controls, a total of 1,076 DDT‐exposed explants and 712 controls being examined. A dose of 50 ppm (parts per million) DDT induced a diffuse hyperplasia and focal proliferations, i.e. pre‐adenomatous lesions, in the first generation. A progressively higher incidence of these lesions was observed at a dose level of 10 ppm, rising from 8.9% in the F1 generation to 39.9% in the Fa generation; however the incidence dropped in the F4 and F5 generations (30.1% and 20.1% respectively). These observations may be suggest that DDT an oncogenic agent but with only a relatively weak activity.
Progestin secretion in 3‐methylcholanthrene‐treated rats
Authors: Moon Richard C. , Young Stretton 
Published: February 2007

AbstractThe mechanism of deciduomata maintenance by 3‐methylcholanthrene (MCA) was investigated in normally cycling Sprague‐Dawley rats. Animals received daily injections of ovine prolactin (LTH) from days 1‐4 following estrus (pre‐trauma period). On days 5 to 8 (post‐trauma period), each rat received either daily injections of LTH, sesame oil intragastrically, or 10 mg 3‐methylcholanthrene (MCA) in 1 ml sesame oil intragastrically. Other rats were either adrenalectomized, ovariectomized or hypophysectomized at the time of uterine traumatization on day 4. Results showed that rats which were not treated with LTH but in which the uterus was traumatized did not develop deciduomata, whereas 80% of rats treated with 5 IU LTH during the post‐trauma period were positive. Rats receiving 10 IU LTH during the pre‐trauma period but untreated during the post‐trauma period did not develop deciduomata. However, 27% of rats were positive when fed oil during the post‐trauma period. In the second experiment, 1 ml oil prior to and during the pre‐trauma period resulted in all negative responses when oil was fed during the post‐trauma period. All rats receiving LTH during the pre‐trauma period followed by MCA during the post‐trauma period were positive. None of the ovariectomized or hypophysectomized rats exhibited deciduomata when treated with MCA during the post‐trauma period. However, 75% of the adrenalectomized rats showed positive reactions. These data indicated that MCA effects release of progestin in quantities sufficient to maintain deciduomata and that both the pituitary gland and ovary are essential for this reponse.
Immunological studies on mouse mammary tumors. vi. further characterization of a mammary tumor antigen and its distribution in lymphatic cells of allogeneic mice
Authors: Chang Shaoyuan , Nowinski Robert C. , Nishioka Kusuya , Irie Reiko F. 
Published: February 2007

AbstractA new lymphatic cell antigen of some laboratory mice which also occurs as a tumor‐specific antigen of ascitic mammary tumors of C3H mice was discovered. This antigen is not present in normal cells of C3H/He mice and is therefore capable of eliciting tumor‐specific immune reactions in C3H/He mice carrying that particular tumor, and also appears as an alloantigen in many of the 24 strains of laboratory mice examined, such as C57Bl/6, AKR, C58, 129, C57L, H‐2H, 101, RF, SJL/J and Swiss mice.The name “MM antigen” seems appropriate for this cross‐reacting antigen detected on the surface of lymphatic cells. The antigen is regulated by a dominant gene independent of other known alloantigens. A designation of the locus MMa was given for this newly discovered antigen.The similarity and difference between this antigen and TL antigen are discussed.
Polycyclic hydrocarbon‐produced toxicity, transformation, and chromosomal aberrations as a function of aryl hydrocarbon hydroxylase activity in cell cultures
Authors: Benedict W. F. , Gielen J. E. , Nebert D. W. 
Published: February 2007

AbstractThe cytotoxic effect of benzo[a]pyrene alone in fetal rat hepatocytes in culture is prevented by phenobarbital. Benzo[a]pyrene is not toxic to HTC, A9, or HeLa cells in which aryl hydrocarbon hydroxylase activity is either absent or very low; however, benzo[a]pyrene is cytotoxic to each of these three established cell lines grown together with the liver cells in the presence of phenobarbital. Polycyclic hydrocarbon‐produced cytotoxicity is associated with chromatid breaks, whereas aneuploidy is more closely correlated with malignant transformation of hamster secondary cultures. Benz[a]anthracene or a‐naphthoflavone competitively inhibits the hydroxylation of other polycyclic hydrocarbons such as the carcinogens 7,12‐dimethylbenz[a]anthracene or benzo[a]pyrene. The exposure of fetal hamster secondary cells to excessive amounts of benz[a]anthracene prior to, during, and following treatment with 7,12‐dimethylbenz[a]anthracene prevents malignant cell transformation from occurring.
Counteraction of the blocking of cell‐mediated tumor immunity by inoculation of unblocking sera and splenectomy: immunotherapeutic effects on primary polyoma tumors in rats
Authors: Bansal S. C. , Sjögren H. O. 
Published: February 2007

AbstractCirculating lymphocytes of rats carrying progressively growing polyoma tumors are specifically cytotoxic to polyoma tumor cells in vitro. The serum of such rats can block this lymphocyte cytotoxicity, an effect probably mediated by tumor‐specific antigen‐antibody complexes. Inoculation of blocking serum into rats has previously been shown to facilitate tumor growth. It is now demonstrated that so‐called “unblocking” antibodies can be produced by immunization of BCG primed rats or rabbits with tumor cells. These antibodies can counteract the effect of specific blocking sera and tumor eluate in vitro.When inoculated into rats which had previously received a polyoma tumor isograft, unblocking serum was found to inhibit the appearance of (or counteract) the blocking activity of serum in four of five rats. Tumors in these four rats grew progressively for 10‐12 days and then completely regressed.The effects of inoculation of unblocking sera into rats carrying primary kidney sarcomas, and subjected to splenectomy, were studied by in vitro tests for blocking and unblocking activity and for homologous complement‐dependent cytotoxicity on serially‐drawn serum samples from all treated rats, as well as for cytotoxicity of circulating lymphocytes from some of the animals. The serum blocking activity decreased or disappeared in all rats treated with unblocking serum while animals inoculated in parallel with control serum showed no such alteration. While sera of untreated rats or rats inoculated with control serum never had any detectable homologous complement‐dependent cytotoxic activity, such activity was demonstrated on several occasions in all tested rats inoculated with unblocking sera. Unblocking activity was observed in several of the treated animals.Inoculating of unblocking sera from either rats or rabbits in combination with splenectomy led to the disappearance of grossly visible tumor in two rats and to retardation of the tumor growth rate in seven of nine other rats. The survival time of nine of 11 rats treated with unblocking sera was significantly prolonged. These results show that immunotherapeutic effects can be achieved by serum treatment combined with splenectomy. Although other mechanisms have not been excluded, the “vertical” in vitro analysis of various facets of the anti‐tumor immune status of these animals supports the hypothesis that procedures counteracting the blocking serum activity in vivo will allow the already present immune lymphocytes to exert their cytotoxic effect and thereby eliminate tumor cells.
Experimental evolution of cell populations of chinese hamster treated with colchicine. induction of high degree of ploidy and a phase‐specific lethal effect
Authors: Palitti F. , Rizzoni M. 
Published: February 2007

AbstractCell cultures of Chinese hamster were treated for 4 h with colchicine 10−4M soon after pulses of H3TdR. If, after being treated with colchicine, the cultures are replaced in a normal medium, there is no resumption of proliferation and the cells follow a progressive polyploidization as a result of repeated C‐mitoses. If, instead, the cultures are trypsinized or detached mechanically, and then plated again, or if the culture medium is changed periodically, the cultures resume their division processes. This phenomenon has been interpreted as resulting from the progressive dilution of intracellular as well as free colchicine according to Borisy aéd Taylor (1967a, b). The resumption of proliferation is not immediate but progressive. The later the cultures resume their proliferation the higher the degree of ploidy. In these cultures, characterized by high ploidy, there is an increase of the percentage of multipolar mitoses and of the number of poles. It is impossible to maintain in the same cultures a high degree of ploidy, which decreases progressively as a result of the multipolar mitoses. All the cells become polyploid, without regard to the phase of the cycle in which they are at the time of treatment. But the cells that were in G1, M and G2 can complete at the most two cycles, going into mitosis with a decreasing frequency; after 70 h they disappear rapidly from the population. This pattern is identical in the cultures that resume proliferation as well as in the other ones. The cells found in late‐S and above all in G2 at the time of treatment may endoreduplicate and appear as endoreduplicated mitoses 22‐24 h after treatment with a 10‐15% relative frequency. Some assumptions have been made in order to explain the phase‐specific response in regard to the lethal effect as well as to endoreduplication. We have related these results to the moment at which colchicine enters the cells.
Étude, chez le hamster syrien, du pouvoir oncogène du virus sv 40 irradié par les rayons ultraviolets
Authors: Et René Wicker , Coppey Jacques 
Published: February 2007

AbstractThe tumorigenicity of SV40 in new‐born hamsters was enhanced by moderate U.V. irradiation (10,000 ergs. mm−2) of the virus provided that at least 105 viral particles were injected. This enhancement phenomenon was suppressed by the addition of normal virus to the irradiated inoculum. Strong U. V. irradiation (50,000 ergs. mm−2) lowered the tumorigenic activity.
Radioimmunoassay of carcinoembryonic antigen in extracts of human colon and stomach
Authors: Martin F. , Martin M. S. 
Published: February 2007

AbstractRadioimmunoassay is used to characterize and quantitatively determine CEA in perchloric extracts of human stomach and intestine, normal, foetal or cancerous. High concentrations of CEA were found in primary adenocarcinomas of the colon and in their metastases to liver. CEA could also be detected, in lesser amounts, in six colonic mucosa removed for non‐cancerous diseases, in two specimens of foetal gut and in five out of six gastric carcinomas. On the other hand, CEA could not be found in non‐cancerous gastric mucosa. Comparison of inhibition curves shows that CEA present in non‐cancerous colon and purified CEA isolated from metastatic colonic cancer have the same immunological reactivity.
Effect of cyclophosphamide on syngeneic transplantation of para‐adenovirus‐7‐transformed tumor cells in hamsters
Authors: Lausch Robert N. , Ross Steven E. , Rapp Fred 
Published: February 2007

AbstractThe effect of cyclophosphamide on the transplantability of hamster tumor cells transformed by PARA‐adenovirus 7 was investigated. Normally, such syngeneic transplants seldom, if ever, regress spontaneously. It was found that chemotherapy was remarkably effective against this neoplasm. A single inoculation of the drug (200 mg/kg) prevented the growth of 104‐105 transplanted cells, and promoted regression of palpable tumors. Weekly drug inoculations prolonged the survival of hosts bearing large neoplasms. Animals successfully treated proved to be resistant to subsequent tumor‐cell challenge. The chemical did not prevent tumor growth if given prior to the transplant. There is suggestive evidence that host tumor resistance may have contributed to the success of cyclophosphamide therapy.
Quantitative studies on the binding of syngeneic antibody to the surface antigens of akr‐virus‐induced rat lymphoma cells
Authors: Boone Charles W. , Brandchaft Phyllis R. , Irving Dianne N. , Gilden Raymond 
Published: February 2007

AbstractThe binding of rat antibody to G cell surface antigen (GCSA) of syngeneic, AKR‐virus‐induced lymphoma cells was studied by performing certain titration procedures using mixed immune and normal sera labelled with different iodine radioisotopes, a technique which permits precise correction for non‐specific adsorption. Using plots of titration data which conformed to linear equations derived from the mass action law, we determined the following constants: (1) The average density of antibody molecules bound to GCSA sites was 6.9 × 106 per cell, and 11,300 per square micron; (2) The average equilibrium constant of the GCSA‐antibody association reaction was 6.54 × 106 ℓmole−1; (3) The mean binding affinity (ΔF°) of the GCSA‐antibody bond was —9.17 Kcal mole−1; (4) The rate constant for antibody dissociation at 0°C was 3.67 × 10−5 sec−1.
Antigenic diversity of tumors chemically induced within the progeny of a single cell
Authors: Basombrí Miguel Angel , Prehn Richmond T. 
Published: February 2007

AbstractTo explain why the antigens of tumors induced by oncogenic hydrocarbons are individually distinct, it has been suggested that the carcinogen induces a mutation‐like hereditary alteration expressed in the cell membrane. An alternative explanation recently proposed is that the tumor antigens pre‐exist in the normal precursor cells. Since each precursor cell contains different antigens, these are not in sufficient quantity to be recognized by the immune mechanism until clonal amplification occurs in the tumor.In order to distinguish between these propositions, low tumorigenic BALB/c 3T3 cells were first cloned in vitro and the progeny cells were then neoplastically transformed by methylcholanthrene in diffusion chambers in the abdomen of mice. The antigens of the tumors induced were still individually distinct, even though they all had been derived from the same original cell.It is concluded that the antigenic diversity of chemically induced tumors cannot be explained solely on the basis of cloning of pre‐existing variants.
The formation of variants with a reversion of properties of transformed cells. VII. Chromosome numbers and re‐reversion in subtetraploid variants
Authors: Hitotsumachi Shinya , Schaki Rina , Padeh Baruch , Rabinowitz Zelig , Sachs Leo 
Published: February 2007

AbstractVariants from polyoma virus transformed cells in which reversion was not associated with a loss of the virus genome have been studied at 3 and 33 weeks after clone isolation. The variants re‐reverted during this in vitro cultivation for properties which were initially suppressed. This re‐reversion was associated with an increase in the total chromosome number from a lower to a higher subtetraploid chromosome number.
Sensitivity of Epstein‐Barr virus (EBV) producer and non‐producer human lymphoblastoid cell lines to superinfection with EB‐virus
Authors: Klein George , Dombos Laszlo , Gothoskar Balwant 
Published: February 2007

AbstractTwenty‐nine lymphoblastoid lines and one IgE‐producing myeloma line of human origin were exposed to Epstein‐Barr virus (EBV) concentrates in vitro. The adsorption of the virus to the outer cell membrane was assessed by counting the number of direct membrane fluorescence‐positive cells immediately after infection and by the direct radioimmune membrane labelling method. Reference reagents were derived for both tests from the same serum (“Agnes”), containing antibodies against EB‐viral envelope and capsid antigens. The intracellular course of infection was followed by counting the number of cells that responded with the development of early antigen (EA) 48 h after infection. The 11 lymphoblastoid lines that produced no EBV‐determined membrane and early antigens adsorbed the virus, although there were quantitative differences between them. EA‐positive cells appeared in significant numbers in only seven of them, however. Four lines remained EA negative in spite of a relatively good adsorbing capacity. The IgE‐producing myeloma line showed neither virus adsorption nor EA development.Eighteen lymphoblastoid lines were “producers”, or “abortive producers”, i.e.a small proportion of the cells continuously generated two or three of the immunofluorescence‐detectable viral antigens, MA, EA and VCA. Nine lines failed to adsorb significant virus quantities and showed no certain increase of EA‐positive cells. The resistance of these lines to superinfection is probably determined at the level of viral receptors. Five lines showed a relatively good virus adsorption, but this was not followed by any significant increase in the number of EA‐positive cells. Four lines showed good adsorption and also responded with a significant increase in the number of EA‐positive cells.The same responses can thus be found to EBV‐superinfection in producer and non‐producer lines, but the producer lines show a strong preponderance of superinfection‐resistant lines with an adsorption block at the receptor level.
Antigènes cellulaires transitoires du foie de rat. II. Effet des inhibiteurs de synthèse sur les fœtoprotéines sériques a la fin du premier mois de vie et après intoxication hépatique aiguë
Authors: de Néchaud B. , Uriel J. 
Published: February 2007

AbstractChez de jeunes rats de moins d'un mois, la décroissance sérique de l'α‐fœtoprotéine (α‐FP) ou de la lipoprotéine‐estérase est accélérée par la cycloheximide. La concentration d'αM‐fœtoprotéine (α‐M‐FP) semble insensible à cet inhibiteur mais décroit sous l'effet de l'actinomycine D. La distribution des taux de variation de la concentration d'α‐FP n'est pas influencée par l'actinomycine D. Au cours d'intoxications hépatiques aiguës, la réapparition d'α‐FP et l'augmentation de la teneur en αM‐FP ont été démontrées. L'intoxication par la diméthylnitrosamine provoque la secrétion d'une quantité décelable d'α‐FP jusqu'à l'ǎge de 2 mois et demi. Il s'agit très probablement d'une synthèse “de novo” de ces fœtoprotéines comme le prouvent, d'une part, l'incorporation de L‐leucine‐C14, et de l'autre, l'inhibition de cette incorporation par la cycloheximide. L'action de l'actinomycine D sur l'incorporation de leucine marquée n'a pas pu ětre mise en évidence par la technique immunoautoradiographique. Il a cependant été démontré que son administration provoque une diminution des niveaux sériques des deux fœtoprotéines les trois premiers jours qui suivent l'injection du toxique.