bluuebunny/crossref_metadata_2025 huggingface dataset:
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

Circulating 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

Cell 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

The 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

Radioimmunoassay 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

The 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

The 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

To 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

Variants 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

Twenty‐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

Chez 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.
Cellular immunity to human urinary bladder carcinoma. I. Correlation to clinical stage and radiotherapy
Authors: O'Toole C. , Perlmann P. , Unsgaard B. , Moberger G. , Edsmyr F.
Published: February 2007

As tested in vitro in a microcytotoxicity assay, purified peripheral blood lymphocytes from patients with carcinoma of the urinary bladder have a specific destructive effect on primary cultures of autologous and allogeneic tumour target cells, as well as on bladder carcinoma cell lines. No specific effect is observed on cells derived from normal tissues or tumour cells of other histogenic origin. Serial tests made on individual patients have shown that the incidence of lymphocyte cytotoxicity varies with the clinical staging of the disease. While 88% of patients with localized tumours, stage T1‐T2, have a response before treatment, the corresponding figure for those with T3‐T4 stage tumours is 41%. Local radiotherapy in tumour doses of 3,500–8,400 R either destroyed or diminished existing cytotoxicity. The response remained depressed as long as irradiation was continuous. After therapy all patients with T2 stage tumour redeveloped a response, usually within 7 days. While 80% of T3 patients had cytotoxicity at this time, the incidence in T4 cases was 50%. In some T3 and T4 patients no response redeveloped after radiotherapy or conversely a response was induced by the treatment. Patients lacking cytotoxicity after therapy invariably had distant metastases and/or large residual tumours detected within 3 months. Weak post‐therapy cytotoxicity was usually accompanied by development of recurrent tumour or distant metastases during a 9‐month observation period; this was not seen in patients whose post‐irradiation cytotoxicity was strong during this time. In the absence of viable tumour the post‐irradiation response seems to wane with time. Evidence for this comes from patients tested 1‐10 years after radiotherapy. Here the presence of cytotoxic lymphocytes was usually associated with viable tumour. The majority of patients clinically tumour free had no response. Maintenance of lymphocyte cytotoxicity, as measured in this system, therefore appears to require the presence of either viable tumour or tumour‐derived material. This cytotoxicity is inhibited however by large viable tumours and also metastases.
Cellular immunity to human urinary bladder carcinoma. II. Effect of surgery and preoperative irradiation
Authors: O'Toole C. , Perlmann P. , Unsgaard B. , Almgård L. E. , Johansson B. , Moberger G. , Edsmyr F.
Published: February 2007

A group of patients with carcinoma of the urinary bladder treated by local resection or total cystectomy were studied in regard to tumour specific cytotoxicity of their lymphocytes. Only one in a group of five, treated by transurethral resection, had cytotoxic lymphocytes when tested within 1 yr after surgery. This patient alone in the group had a residual growing tumour at the time of testing. Total cystectomy in five patients led to complete disappearance of cytotoxicity in two and almost complete disappearance in a third. One patient was negative both before and after surgery. These four patients were free of macroscopic tumour when tested 4–8 weeks after surgery. The patient whose lymphocytes were strongly cytotoxic after surgery had suspected residual tumour foci in the urethra at 5 weeks after operation. Preoperative irradiation of the tumour produced a systemic response which was maintained after total cystectomy in three of four patients for at least 3–7 months. The patient who was negative when tested after cystectomy was in poor general health. All four patients were clinically tumour‐free at the time of post‐operative lymphocyte sampling. These results favour the interpretation that the maintenance of a cellular response to this tumour is dependent on the presence of tumour material in the body. Stimulation of the immune response measured may be produced or maintained by localized primary tumours or by material released systemically as a result of tumour necrosis.
Effect of host strain and H‐2 type on spontaneous regression of murine leukemia
Authors: Dietz Michael , Rich Marvin A.
Published: February 2007

The susceptibility of 14 mouse strains to a regressing and a conventional strain of Friend leukemia virus was studied. A comparison of leukemia incidence and latent period to leukemia development demonstrated that, for all mouse strains, the susceptibility to both viruses was the same.

Leukemia regression occurred in 10 of the 12 mouse strains susceptible to regressing Friend virus (RFV). Regression of leukemia in mice inoculated with conventional Friend Virus (CFV) occurred primarily in those mouse strains homozygous for the H‐2k allele. RFV‐induced leukemia regression was observed in mice homozygous for H‐2a, H‐2q, H‐2s, H‐2d, and H‐2k. The H‐2 locus does not appear to be a determinant in leukemia regression.
DNA repair following exposure of human lymphocytes to 4‐nitroquinoline‐1‐oxide
Authors: Jacobs Allan J. , O'Brien Richard L. , Parker John W. , Paolilli Patricia
Published: February 2007

The carcinogen 4‐nitroquinoline‐1‐oxide (4NQO) is known to induce unscheduled DNA synthesis when administered to a number of mammalian cells. This effect was demonstrated in human lymphocytes. The degree of unscheduled DNA synthesis was found to be correlated with time and with 4NQO concentration. 4NQO was demonstrated to inhibit DNA replication in actively dividing lymphocytes.

In addition, human lymphocytes treated with the mitogen phytohemagglutinin‐M (PHA‐M) were allowed to incorporate bromodeoxyuridine (BUdR) into one chain of DNA in replicative synthesis. Following this, the BUdR was removed and the cells were incubated with 4NQO and tritiated thymidine. DNA isolated from these cells was fractionated by cesium chloride gradient centrifugation into a BUdR‐containing fraction of replicated DNA and a light fraction of DNA which had not yet replicated when incubated with BUdR. 3H‐thymidine was found in the heavy fraction of DNA from 4NQO‐treated cells which contained no newly replicated DNA. It was concluded that this represented repair synthesis.
Cellular reactions against Burkitt lymphoma cells. I. Colony inhibition with effector cells from patients with Burkitt's lymphoma
Authors: Hewetson John F. , Golub Sidney H. , Klein George , Singh Surjit
Published: February 2007

A micro‐assay colony inhibition (CI) test has been developed for studying cell‐mediated reactions against lymphoblastoid target cells. The assay makes use of the ability of the target cells, but not the effector cells, to grow in discrete colonies in semi‐solid medium. Peripheral blood leukocytes from patients with Burkitt's lymphoma and nasopharyngeal carcinoma, and from controls, were used as effector cells in this assay against the Burkitt lymphoma derived lymphoblastoid cell line P3HR‐I. Only five of the 62 samples from patients with these diseases inhibited colony formation by more than 30%. When phytohemagglutinin‐stimulated cells were used in the CI test, colony formation was greatly reduced. CI activity of PHA‐stimulated cells appeared to be correlated to the degree of stimulation, as determined by incorporation of tritiated thymidine. Preliminary data indicate that lymph‐node cells, but not peripheral leukocytes, tested against autochthonous and allogeneic cell lines, are capable of significant colony inhibition.
Cellular reactions against Burkitt lymphoma cells. II. Effector cells obtained by allogeneic stimulation in mixed leukocyte cultures
Authors: Golub Sidney H. , Hewetson John F. , Svedmyr Erik A. J. , Singh Surjit
Published: February 2007

A new colony inhibition test has been employed to detect effector cell activity of normal human leukocytes after stimulation with allogeneic cells. The responding cells in one‐way mixed leukocyte culture show strong activity in this assay, and effector cell activity is at least in part antigenically specific. Specificity of the CI activity was found to be dependent on the dose of effector cells added and the nature of the stimulator cell used. Stimulation with allogeneic leukocytes yielded a response which was strongly restricted in its CI activity to the appropriate target cell, while stimulation with Burkitt lymphoma‐derived cell lines resulted in CI activity which was cross‐reactive with other BL‐derived cell lines. These data indicate the presence of cross‐reactive antigens on two LCL lines derived from Burkitt lymphomas which can sensitize normal leukocytes to yield a cytotoxic response.
Spontaneous appearance of cytopathology and rat C‐type virus (WF‐1) in a rat embryo cell line
Authors: Bergs Victor V. , Pearson Gary , Chopra Harish C. , Turner Willie
Published: February 2007

An established line (WF‐1) of Wistar/Furth rat embryo cells spontaneously developed cytopathology after about 2 years in vitro. The cellular changes appeared within 5–7 days after subculturing of the cultures and consisted of altered rounded and fusiform cells with dark, prominent nuclei. These changes increased after removal of bovine amniotic fluid from the culture nutrient but were not apparent if the cultures were subcultured at 3–4 day intervals. Most of the altered cells were viable, but they failed to multioly under the conditions employed. Electron microscopical examination of the WF‐1 cells revealed numerous extracellular and budding C‐type virus particles. The cells, when inoculated into rats, produced progressively growing fibrosarcomas which also contained C‐type particles. Initially the WF‐1 virus failed to produce visible effects in the REL line of Sprague‐Dawley rat embryo cells. Several months later, upon concentration and banding at 1.16 g/cm3 in a sucrose gradient, low‐titered infectious virus of about I TCID50 per 10,000 virus particles was recovered. This produced foci of predominantly viable rounded cells in REL cultures similar to those induced by the C‐type virus (RMTDV or BV‐1) previously isolated from chemically induced rat mammary tumors. Immune BV‐1 serum prevented the WF‐1 virus from producing these cellular effects. Tests for properties characteristic of murine leukemia viruses (gs‐1 antigen, gs‐3 interspecies antigen, and the XC reaction) were negative indicating that the WF‐1 virus was not a mouse virus. These observations suggested that upon prolonged cultivation in vitro the WF‐1 rat embryo cells spontaneously liberated a rat C‐type virus related to the BV‐1. Whether the cell‐altering and partially lethal effects produced by the WF‐1 virus were due to some cytopathic C‐type particles in a generally non‐cytopathic population or reflected the concentration of only one biological type of particles needs further study.
Bias in an African cancer registry
Authors: Templeton A. C. , Bianchi Alexis
Published: February 2007

The returns of the Kampala Cancer Registry, Uganda, which registers cases diagnosed in the whole of the country, have been analysed to discover if changes in patterns of registration have occurred over a 20‐year period. The age distribution has remained surprisingly constant. Comparison with the best data available in the country, from a relatively small area adjacent to the main teaching hospital, suggests that in the first years of study deeply placed tumours were only half as likely to be diagnosed as more superficially placed lesions. Registration of cancer in females was about half as efficient as in males. Registration bias has diminished as social patterns have evolved and as hospitals have become more accessible but it still considerable. Similar changes occurred in all regions in Uganda which vary markedly in social, ethnic and climatic backgrounds and it is highly likely, therefore, that a similar bias is operating in cancer studies elsewhere in Africa.
Réctions d'hypersensibilité retardée avec des lignées de cellules tumorales humaines cultivées in vitro chez des malades porteurs de tumeurs cérébrales malignes
Authors: Febvre H. , Maunoury R. , Constans J. P. , Trouillas P.
Published: February 2007

Les cellules cultivées in vitro à partir de tumeurs cérébrales humaines se comportent comme des antigènes forts qui permettent de caractériser l'état d'immunité cellulaire des patients atteints d'affection néoplasique. Cette antigénicité croisée, fortement évocatrice de la présence d'un antigène tumoral commun, différent de l'antigène de transplantation associé aux tumeurs, paraǐt pouvoir ětre utilisée dans une certaine mesure dans le diagnostic précoce du processus néoplasique, au měme titre, par exemple, que la cuti‐réaction tuberculinique, mais ne peut préjuger en aucune manière de l'évolution de la maladie. Ces résultats demandent à ětre confirmés sur une plus large échelle. Quoi qu'il en soit, l'isolement de l'antigène et l'expérimentation in vitro nécessaires à l'interprétation des faits observés en clinique se poursuivent.
Embryonic antigen expression in chemically induced rat hepatomas and sarcomas
Authors: Baldwin R. W. , Glaves Dorothy , Vose B. M.
Published: February 2007

Embryonic antigens were detected at the surface of carcinogen‐induced rat hepatoma and sarcoma cells by their reactivity in membrane immunofluorescence tests with sera from multiparous rats. These sera also showed complement‐dependent cytotoxicity for plated target tumour cells, and lymph‐node cells from multiparous rats were similarly cytotoxic when compared with the effects of cells from normal virgin age‐matched controls. These embryonic antigens could be demonstrated on embryonic cells but not on cultured normal adult rat liver cells or lung fibroblasts. The tumour‐associated embryonic antigens were shown to be common to both tumour types and so differ from the individually distinct antigens associated with these carcinogen‐induced tumours which play a major role in immune rejection responses.
Tumorigenicity and agglutination by concanavalin a of Chinese hamster cells and their hybrids
Authors: de Micco Ph. , Berebbi Monique
Published: February 2007

In a previous work we studied the relationship between tumorigenicity and the karyological data of a somatic hybrid derived from two lines of Chinese hamster cells, of which one was tumorigenic and the other had lost its tumorigenicity. In this work, we show the relationship between the two factors previously studied and the agglutinating ability of these cells by Concanavalin A. In order to do this, we first derived a coefficient α to express quantitatively the agglutinating ability with Concanavalin A. This coefficient was a function of the latency period, the time necessary to reach the platform level of agglutinating ability and the degree of agglutination of the cells in presence of a fixed quantity of cells and Concanavalin A. The highly tumorigenic DC‐3F cell line gave a high a value, the non‐tumorigenic DC‐3F/ADX/Aza had a much lower value and the overall hybrid population (HyC) had an intermediary value for α. The clones and the tumors studied show a correlation between the value and the tumorigenicity of the cells involved. The karyological analysis showed, inter alia, a possible correlation between the presence of a marker M2 and a particularly low a coefficient.
Incidence of group‐specific (gs) antigens of type C tumor viruses in spontaneous neoplasms of BALB/cCr mice
Authors: Peters Robert L. , Spahn Gerard J. , Rabstein Louise S. , Turner Horace C. , Huebner Robert J.
Published: February 2007

The incidence of species‐specific gs antigen of the C‐type RNA tumor viruses in the spleen and tumor tissues of BALB/cCr mice (mostly female) with spontaneous neoplasms was determined by the complement fixation (CF) test. Spleen extracts from mice with neoplasms of the reticuloendothelial system (all involving the spleen) were much more frequently positive for gs antigen than spleens of age‐ and sex‐matched normal mice. Among mice with non‐leukemic, solid tumor malignancies the incidence of gs antigen in spleen tissue was elevated, but not significantly, above that found for mice of comparable age, which had no histologic evidence of malignancy. Extracts of tumor tissue from these same tumor‐bearing mice revealed variable incidences of positive reactions exceeding those found for normal connective tissues from the same tumor‐bearing mice. Cell lines derived from solid tumors had uniformly higher rates of gs antigen incidence when compared to the donor tumor or spleen tissues.
The transformation of BHK 21 hamster cells by simian virus 40
Authors: Wiblin C. N. , Macpherson I. A.
Published: February 2007

Although BHK 21 cells remain refractory to direct transformation by SV40 virus even at multiplicities of infection as high as 104 PFU per cell, transformed derivatives may be produced by cocultivation of the untransformed cells with monkey cells infected with SV40 virus.

The characteristics of a cloned SV40‐transformed line (C13/SV) have been studied. The cells showed several of the properties of BHK 21 cells transformed by other oncogenic viruses. High‐passage variants of the line (C13/SV‐M) metastasized from the primary tumour that they induced in hamsters. Metastatic foci were the result of dissemination of the cells, and not due to the release of infectious SV40 virus from implanted cells.

Comparisons between the in vitro and in vivo growth properties of C13/SV and C13/SV‐M cells did not reveal a correlation with metastasizing ability. The C13/SV‐M cells also retained those properties of transformed cells that are probably associated with surface alterations, although the SV40‐specific transplantation antigen may be partially absent or masked in these cells.
The SV40 S antigen; A carcinoembryonic‐type antigen of the hamster?
Authors: Berman Leonard D.
Published: February 2007

In addition to hamster tumor cells induced or transformed by SV40, hamster anti‐SV40 S (Surface) antiserum also reacted with non‐SV40‐exposed cell lines spontaneously induced (BHK 21) or transformed by heterologous oncogenic DNA and RNA viruses in the indirect membrane fluorescent antibody test. The antiserum titered equally with both BHK and SV40‐transformed cells and the reaction could be absorbed with either of these cell lines, or with hamster embryo. The antiserum also reacted with early hamster embryo cells, although various organ cells from late fetuses, newborns and adults were negative. Mouse cell lines spontaneously induced (BALB/c‐3T3) or transformed by SV40 and adenovirus 12 were also non‐reactive. The results suggest that the antigen in question is a hamster somatic antigen present during embryonic life and derepressed in lines of actively growing cells.
Inhibitory effects of BCG on adenovirus tumorigenesis: Dependence on administration schedule
Authors: Ankerst Jaro , Jonsson Nils
Published: February 2007

The cumulative incidence of tumours was registered in CBA mice inoculated with adenovirus type 12 when newborn and treated with BCG in different ways during the latency period. A single subcutaneous dose of BCG at 3–4 weeks of age had a preventive effect, while no prevention could be recorded after a single BCG dose at 9 weeks of age or eight BCG injections at intervals of 1 week. Sera obtained during the latency period were tested for capacity to block lymph‐node cell‐mediated tumour immunity. Blocking activity was detectable in pooled serum of the mice which had been infected with BCG at 9 weeks of age, already at 10 weeks, i.e. 1 to 2 weeks before the appearance of palpable tumours. Blocking activity could not be demonstrated in a serum pool from control mice until 14 weeks after virus inoculation, at which time sera from mice inoculated with BCG at the age of 3 weeks were still negative. The results indicate that the effect of BCG upon tumour development is dependent upon the point of time of BCG treatment and further suggest that BCG treatment initiated at a stage when serum blocking activity is already present can further stimulate the production of blocking factors and tentatively promote tumour development.
Ultrastructural localization of concanavalin a receptors in normal and SV40‐transformed hamster and rat cells
Authors: Bretton R. , Wicker R. , Bernhard W.
Published: February 2007

The distribution of receptor sites for concanavalin A at the surface of normal and SV40‐transformed hamster cell cultures has been studied with the electron microscope after application of the Con A‐peroxidase method. Both normal and transformed cells show a strongly positive reaction. Although it has not been possible in single cases to distinguish with certainty between normal and transformed cells, the cell‐coat reaction of the majority of malignant hamster cultures shows a striking tendency to be more unevenly distributed than in normal controls. This remains true for cultures after relatively few or after many passages, and for lines derived from in vivo induced tumors or from in vitro transformed cultures. This observation confirms results obtained in this laboratory from hamster cells transformed by Polyoma virus or Adenovirus 12. However, in a few rat fibroblast cultures transformed by SV40 virus, we have so far not seen any difference in the cell‐coat reaction between normal and transformed cells. The possible reasons for the more irregular distribution of the cell‐coat reaction product of transformed hamster cells compared to normal controls are discussed.
Mechanism of resistance of Yoshida sarcoma to nitrogen mustard. II. Further evidence for suppressed transport of nitrogen mustard
Authors: Inaba Makoto , Moriwaki Ayako , Sakurai Yoshio
Published: February 2007

Sensitivity of Yoshida sarcoma lines resistant to nitrogen mustard (HN2) was not enhanced by pretreatment in vitro with SH‐blocking agents such as 2,2′‐dithiodi‐pyridine. This fact seems to indicate that content of cellular sulfhydryl groups did not play a great role in acquisition of resistance to HN2. No difference was observed between the sensitive and resistant lines in retention rate of HN2 bound to DNA of the cells during incubation of the cells in an HN‐free medium. These results suggested no considerable difference in the ability to repair DNA in both lines.

Further evidence was added for suppressed transport through the cell membranes of the resistant lines. Damage to cell membranes was proved by vital staining when a concentration of SH‐blocking agents in the pretreatment reached a certain level, and the binding rate of HN2 to DNA of the resistant lines was recovered almost to the same level of the sensitive line by this pretreatment.

However, the binding rate of the sensitive line was not changed by pretreatment with the blocking agents at any concentrations.
Transformation cellulaire maligne et modifications caryologiques: Apport de l'hybridation somatique de lignées de hamster Chinois malignant
Authors: Berebbi M. , Meyer G.
Published: February 2007

Notre étude a porté sur différents clones isolés a partir d'une lignte cellulaire hybride obtenue par fusion de deux sub‐lignées de hamster chinois ayant une origine commune, mais des caractères distincts et, en particulier, des caractéresistiques de transplantabilité. Afin d'ktudier les propriktks de la transformation cellulaire, cette population hybride htttrogkne, decrite par Berebbi et Barski (1971) a été clonée en gélose semi‐molle. Trois critères de la trans formation (eficacité clonale, agglutinabilité à la Concanavaline A et tumorigénicité) ont été étudiés. En eflet, la souche DC‐3F qui est transformie spontanément in vitro a un pouvoir tumorigène maximum, un coeficient d'agglutinabilitk élevé et un rendement en colonie aussi très élevé. Par contre, la souche parentale qui en derive (DC‐3F/A DX/Aza) a perdu son pouvoir tumorigène, agglutine beaucoup plus dificilement et ne nous a pas donné de colonies en gtlose. Or, l'étude de la population hybride de départ nous montre des résultats intemédiaires aussi bien pour la croissance en gélose que pour l'agglutinabilité à la Concanavaline A. De méme, les différents clones issus de la population hybride de départ nous montrent des différences dans le pouvoir tumorigéne et celui‐ci semble encore lié aux modifications des propriétés de surface. En effet, ces clones n'ont pas la méme efficacité clonale en gélose et n'agglu‐tinent pas de la měme maniére. Nous les avons séparés en deux parties, les clones 2 et A qui agglutinent faiblement et les clones 3 et Ebl qui ont un coefficient d'agglutinabilité beaucoup plus élevé. Nous avons étudié en paralléle l'évolution du caryotype de la population hybride in vitro des clones et des tumeurs correspondantes, et nous avons essayé de faire une analyse chromosomique statistique pour chaque souche. C'est ainsi que nous avons essayé d'établir une corrélation entre l'apparition d'un chromosome subtélocentrique, marqueur de l'hybride (la moyenne arithmétique pour ce marqueur étant de 0.85) et le pouvoir tumorigéne. Or, cette moyenne arithmétique du marqueur M2 varie tout au cours des subcultures de l'HyC et dans les différents clones étudiés. II semble donc y avoir une relation entre la présence de ce marqueur et le pourcentage de tumeurs obtenues. Cependant, d'aprés l'etude statistique comparée de chacun des clones et des tumeurs issues de ces clones, le marqueur M2 ne semble pas le seul responsable de la malignité car l'équilibre des autres paires chromosomiques est impliqué dans l'expression de la transformation cellulaire, le marqueur M2 semblant plus spécialement concerné dans les modifications de surface cellulaire. Ce phénoméne polygénique de la transformation cellulaire est donc moins le résultat d'une dominance ou d'une délétion que d'un désquilibre génétique.
The ontogeny of alpha‐foetoprotein in the foetal and neonatal rabbit, and its experimental induction in adult rabbits
Authors: Branch W. R.
Published: February 2007

The relative concentration of AFP in the foetal and neonatal rabbit was studied by immunological methods. A peak foetal concentration of AFP was found between the 24th and 26th days of gestation. AFP could not be detected in newborn serum after the 28th day post‐partum. The concentration of AFP between the 20th and 25th days of gestation was found to rise from 327 mg/100 ml to 525 mg/100 ml.

The synthesis of AFP in young and adult rabbits was successfully induced (a) during liver regeneration following carbon tetrachloride intoxication in rabbits less than 14 weeks of age, and (b) following the induction of hepatomas by oral administration of N.nitrosodiethylamine.
Rescue of the murine sarcoma virus genome from non‐producer cells by the RD‐114 type C virus
Authors: Gilden R. V. , Lee Y. K. , Long C.
Published: February 2007

A pseudotype focus‐forming virus was prepared by fusion of human cells infected with RD‐114 virus and non‐producer hamster cells transformed by murine sarcoma virus. The focus‐forming virus, designated MSV (RD‐114), transformed human fibroblasts, including WI‐38, but no mouse, hamster, or rat embryo cells. MSV (RD‐114) possesses envelope, group‐specific, and polymerase antigenic reactivities characteristic of RD‐114 virus. RD‐114 infected cells were resistant to focus formation by MSV (RD‐114) while no diminution in focus‐forming activity was observed in cells infected with feline leukemia virus.
Radioimmunoassay of alpha‐fetoprotein: A contribution to the diagnosis of choriocarcinoma and hydatidiform mole
Authors: Seppälä M. , Bagshawe K. D. , Ruoslahti E.
Published: February 2007

Determination of the circulating alpha fetoprotein (AFP) can be used to differentiate between choriocarcinoma or hydatidiform mole and normal pregnancy. Whilst a positive pregnancy test is common to all these states, the serum AFP was found to be elevated only when a fetus was present.
The effect of long‐term exposure to DDT on CF‐1 mice
Authors: Tomatis L. , Turusov V. , Day N. , Charles R. T.
Published: February 2007

CF‐1 minimal inbred mice were given technical DDT mixed into the diet at the dose levels of 2, 10, 50 and 250 parts per million (ppm) for the entire life span for two consecutive generations. Exposure to all four levels of DDT resulted in a significant increase of liver tumours in males, this being most evident at the highest level used. In females, the incidence of liver tumours was slightly increased following the exposure to 10 and 50 ppm, while a marked increase was observed following exposure to 250 ppm. In DDT‐treated animals the liver tumours were observed at an earlier age than in untreated controls. The age at death with liver tumours and the incidence of liver tumours appeared to be directly related to the dose of DDT to which the mice were exposed. Four liver tumours, all occurring in DDT‐treated mice, gave metastases. Histologically, liver tumours were either well‐differentiated nodular growths, pressing but not infiltrating the surrounding parenchyma, or nodular growths in which the architecture of the liver was obliterated showing glandular or trabecular patterns.
Inhibition of established transplants of chemically induced sarcomas in syngeneic mice by lymphocytes from immunized donors
Authors: Borberg H. , Oettgen H. F. , Choudry K. , Beattie E. J.
Published: February 2007

Intravenous injections of lymph node cells from immunized BALB/c and (C57BL/‐6 X A) F1 mice and from immunized sheep induced regression or inhibition of established grafts of a methylcholanthrene‐induced sarcoma in syngeneic BALB/c mice.
Transplantable immunoglobulin‐secreting tumours in rats. I. General features of LOU/Ws1 strain rat immunocytomas and their monoclonal proteins
Authors: Bazin H. , Deckers C. , Beckers A. , Heremans J. F.
Published: February 2007

This article describes a peculiar tumour which originates in the ileocoecal lymph node of the LOU/Ws1 strain rat. The tumour cells usually have the appearance of very poorly differentiated lymphoid cells showing a tendency to develop ribosome‐studded ergastoplasmic membranes. In about 60% of the cases, such tumours synthesize monoclonal immunoglobulins of the IgG or IgA class, or Bence‐Jones proteins. These tumours are readily transplantable in isologous hosts or their F hybrids. The great majority of the transplanted growths retain their capacity for immunoglobulin production during many successive passages in vivo.

A scrutiny of older and more recent literature has revealed several descriptions of rat tumours having the same macroscopic and microscopic features as the tumours described here, except for the immunoglobulin‐secreting properties which were never tested in the earlier studies.

It is proposed to call this tumour the rat ileocoecal immunocytoma.
Cell‐mediated reaction against tumors induced by oncornaviruses. I. Kinetics and specificity of the immune response in Murine sarcoma virus (MSV)‐induced tumors and transplanted lymphomas
Authors: Leclerc J. C. , Gomard E. , Levy J. P.
Published: February 2007

Anti‐tumour cell‐mediated immune reactions were studied by the chromium release test (CRT) in mice bearing autochtonous Murine Sarcoma Virus (MSV)‐induced sarcomas or syngeneic transplants of lymphomas with various antigenic specificities. Cytotoxic lymphoid cells were detected during tumor growth, but disappeared rapidly after day 13–15 in “progressors”, and more slowly in mice which were able to reject the tumor (“regressors”). The level of cytolytic activity of lymphoid cells in the spleen of “regressors” did not parallel the immune protection. No blocking of the cytotoxic activity of lymphoid cells was detected in CRT using either “progressor”, or “regressor” sera. The discrepancies which exist between these results and those which were obtained in the same tumor system by colony inhibition test or microcytotoxicity assay may suggest that different phenomena, possibly involving different lymphoid cell populations, were studied by the various methods. The antigenic specificity of the immune reactions which were evidenced by the CRT was not identical to those revealed by serological methods, cross‐reactivity being regularly observed in CRT between FMRGi+ and G+lymphomas.
The surface structure of murine ascites tumors. II. Difference in cytotoxicity of various phytoagglutinins toward yoshida sarcoma cells in vitro
Authors: Tomita Motowo , Kurokawa Tsutoma , Onozaki Kikuo , Osawa Toshiaki , Sakurai Yoshio , Ukita Tyunosin
Published: February 2007

Several phytoagglutinins having different sugar specificities were found to exert different agglutinating activity toward murine ascites cell lines. It was also found that some of these phytoagglutinins, especially.

Ricinus communis.

and.

Abrus precatorius.

agglutinins, inhibited the growth of Yoshida sarcoma (YS) cells and showed a strong cytotoxic effect. This kind of cytotoxicity of.

Ricinus communis.

agglutinin, which is specific for galactose, was shown to be counteracted by the addition of galactose but not of glucose, and this fact indicated that the cytotoxicity of the phytoagglutinin is related to the binding specificity of the agglutinin toward the sugar chains on the cell surface. On the other hand, in some phytoagglutinins, the cytotoxicity was found to be relatively low even when their agglutinating activity was remarkably high. On the basis of these results, the role of the sugar chains on cell surface in cellular functions is discussed.
Properties of an SV40‐transformed hamster cell line resistant to actinomycin D
Authors: Wicker R. , Bourali M.‐F. , Suarez H. G. , Cassingena R.
Published: February 2007

The biological properties of a hamster cell line Cl 2 TSV‐5/R derived from an SV40 tumour and made resistant to Actinomycin D (2 μg/ml) were investigated, in particular: tumorigenicity in vitro growth on plastic or in soft agar, agar, persistence of SV40 specific neoantigens (T and TSTA), and caryotype. When compared to the parental cell line (Cl 2 TSV‐5), the tumorigenicity and the ability to grow in soft agar of the Cl 2 TSV‐5/R cells were strongly reduced (approximately 1,000 fold). Their growth on plastic was also clearly slowed. Although the SV40 T antigen was still present in all the resistant cells they no longer had immunosensitivity to the SV40 specific graft rejection test. The caryotype of Cl 2 TSV‐5/R cells was comparable to that of the Cl 2 TSV‐5 cells.