bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of adrenalectomy on the growth of mammary tumours induced by 3‐methylcholanthrene in rats
Authors: Daniel P. M. , Prichard Marjorie M. L.
Published: February 2007

Mammary tumours were induced in rats by intragastric administration of 3‐methyl‐cholanthrene. More than 75% of the tumours attained palpable size between 3 and 11 weeks after the last dose of the carcinogen. Adrenalectomy did not inhibit the growth of tumours already present and appeared even to encourage tumour growth. However, the stimulating effect of adrenalectomy was outweighed by the inhibition of tumour growth caused by subsequent removal of the ovaries.
Biochemical mechanisms of drug resistance IV. Development of resistance to 5‐azacytidine and simultaneous depression of pyrimidine metabolism in leukemic mice
Authors: Veselý J. , Čihák A. , Šorm F.
Published: February 2007

The development of resistance of leukemic AKR mice to 5‐azacytidine administered in small doses was investigated. The activity of uridine kinase decreased simultaneously with the development of resistance. The gradual shortening of the survival time of treated animals and the depression of enzyme activity had a continuous character. The application of 5‐azacytidine along with hydrocortisone or actinomycin D did not appreciably affect the development of resistance. In leukemic cells resistant to 5‐azacytidine the incorporation of uridine, cytidine and 5‐azacytidine itself into ribonucleic acids was depressed in accordance with the impaired anabolic transformations of 5‐azacytidine in vivo as well as with the soluble fraction in vitro.
Neutralization of the oncogenicity of moloney sarcoma virus and moloney leukemia virus by anti‐gross serum
Authors: Fefer A. , McCoy J. L. , Glynn J. P.
Published: February 2007

A potent and specific rat anti‐Gross serum effectively neutralized the oncogenicity of Moloney Sarcoma Virus (MSV) and Moloney Leukemia Virus (MLV) of BALB/c origin. It also reacted against a BALB/c Moloney leukemia but not against a mineral oil‐induced BALB/c plasmacytoma by the indirect fluorescent antibody test. The results suggest that either Gross virus has some antigens in common with both MSV and MLV, or that Gross virus shares antigens with MLV which, in turn, determines the virion coat antigens of MSV.
Epidemiological findings and electron microscopic observations in human leukemia and canine contacts
Authors: van Hoosier G. L. , Stenback W. A. , Mumford D. M. , Hill W. A. , Dunn S. C. , Macdonald E. J. , Macdonald M. C. , Taylor H. G. , Trentin J. J.
Published: February 2007

Three temporally and geographically restricted cases of acute lymphatic leukemia in children, in which two of the three patients had an unusual and suspicious history of canine contact, were investigated. Subsequent epidemiological studies showed a high frequency of dog contact and of dog bite in 100 leukemic, 48 lymphomatous, and 194 nonneoplastic control children. Thirty percent of the leukemic children had no history of dog contact or dog bite. Thin‐section electron microscopy studies of dog specimens revealed the presence of murine leukemia virus‐like particles in specimens from control dogs, tumorous dogs and non‐tumorous dogs associated with human leukemics. A higher incidence of such particles was found in the blood and urine of associated dogs than of tumorous or control dogs. These findings neither prove nor disprove an etiological relationship between dogs and cases of human leukemia. It is hoped that they will stimulate others to consider animal contacts with reference to human neoplastic disease.
Lactate dehydrogenase isoenzyme patterns in the tumour‐bearing colon
Authors: Langvad E.
Published: February 2007

The lactate dehydrogenase (LDH) isoenzyme pattern of the tumour‐bearing colon has been studied in homogenates by disc‐electrophoretic separation. The preponderance of M‐LDH in malignant tissue has been confirmed.

It has been shown that the isoenzyme pattern may be altered in the absence of morphological changes. Thus, the metabolic change is not specifically dependent on the existence of tumorous parenchymatous changes as currently recognized by light microscopy.

It is suggested that the tumour develops within a tissue where metabolic modifications may precede the stage of morphological malignancy.

It appears, therefore, that the alteration of the enzyme pattern might be symptomatic of an established, but very early, neoplastic condition, the microscopic recognition malignancy being a later development.
Survey of human cancer patient sera for adenovirus “T” antibody by immunofluorescence
Authors: Malmgren Richard A. , Rabson Alan S. , Carney Paula G.
Published: February 2007

Serum from 126 patients with various types of cancer and from 63 normal controls was examined by immunofluorescence for adenovirus 12 “t” antibody. Fourteen per cent of the cancer patients and 11% of the normals had antibody reactive with the adenovirus‐12‐infected green monkey kidney cells. The types of cancer which seemed most often to be associated with positively reacting sera were brain tumors, breast cancer and colon cancer.
Haemagglutinin production in tumour‐bearing and leukaemic mice
Authors: Gelzer J. , Dietrich F. M.
Published: February 2007

Time‐course studies on anti‐sheep erythrocyte haemagglutinin formation after a single injection of antigen in tumour‐bearing and leukaemic mice yielded the following results: 1) Mice bearing (a) transplanted Ehrlich carcinoma or (b) primary mammary adenocarcinoma exhibited normal humoral antibody responses irrespective of the stage of tumour growth and the condition of the tumour‐bearing animal; 2) Rauscher leukaemic mice, on the other hand, showed marked abnormalities in antibody‐producing capacity. Sequential measurements revealed an increasing degree of immunodepression as the leukaemia progressed. However, the impairment of antibody production was already increased appreciably during the first aleukaemic phase of Rauscher disease 10 days after inoculation with the leukaemic virus; this was followed, during the second leukaemic phase, by a slight return of haemagglutinin‐forming capacity although not to normal levels. The terminal leukaemic stage was characterized by the strongest immunodepression recorded in the course of Rauscher disease.

All leukaemic mice eventually exhibited a late immunodepression approximately 30 days after immunization. The various degrees of qualitatively and quantitatively differing immunological abnormalities are discussed in relation to the pathogenesis of Rauscher disease.
Continuous viral replication and cellular neoplastic transformation in cultures of normal rat thymus infected with gross leukemia virus
Authors: Ioachim Harry L. , Berwick Leonard
Published: February 2007

To develop a system for the study of Gross leukemia virus (GLV) replication in vitro, cultures of embryonal rat thymus were infected, grown for long intervals, and periodically examined for infectious virus. Supernatants assayed in susceptible animals induced leukemia in 93%, and electron micrographs of cultures confirmed the presence of abundant virus particles. Comparable cultures of spleen and kidney did not support viral replication. Morphologic differences were noted between the appearance of virus‐infected and control cultures. Isotransplantation of the former in conditioned rats resulted in formation of tumors at the site of injection. These tumors had the histologic pattern of reticulum‐cell sarcomas, were serially transplantable in non‐conditioned hosts, and continued to carry the initial GLV. The thymus, which is a target organ for GLV in vivo, appears to be similarly favorable for its replication in vitro. In addition, neoplastic transformation has occurred in these cultures, presumably induced by GLV.
Mise en évidence chez le rat d'un facteur génétique dans la cancérisation par le diméthylaminoazobenzène. Presence in the rat of a genetic control of dab‐carcinogenesis
Authors: Chauveau Jean , Decloitre Françoise
Published: February 2007

Two strains of white rats, one of which (Sprague‐Dawley) was sensitive, another (Wistar) not, to liver cancerization by DAB, were studied comparatively in an attempt to find biochemical characteristics which might explain this difference, that is changes in the activity of the enzyme, DAB‐reductase, and in the binding of azo metabolites to liver proteins.

The animals were administered a whole diet, rich in proteins and in vitamins. When not fed DAB, the activity of DAB‐reductase was five‐fold higher in Wistar than in Sprague‐Dawley rats; the continuous administration of DAB causes a progressive decrease of the enzyme activity in the two strains. After 10 days of carcinogenic diet the amounts of azo proteins are maximal and at this time they are twice higher in Sprague‐Dawley than in the Wistar rats. Hepatomas appear in the Sprague‐Dawley strain without a lag phase, as early as the fifth week of treatment.

The resistance to cancerization appears to depend principally on a genetic factor which would allow a more or less efficient detoxification, mediated by the enzyme, DAB‐reductase.
Studies on a naturally occurring human antibody active against mouse landschutz ascites tumor cells: I. Cytotoxicity assay system and quantitation in normal sera
Authors: Laskov R. , Simon E. , Gross J.
Published: February 2007

1. A quantitative cytolytic assay system was developed for the titration of the natural cytotoxin of human serum (NHS) which is active against Landschutz ascites tumor cells. The assay system consists of NHS52 or NHS as a source of antibody and human umbilical cord serum as a source of complement.

2. Von Krogh plots of the cytotoxin and complement titration data gave 1/n slope values which were comparable to those obtained in the literature for acquired hemolytic and cytolytic immune systems. The values for the cytotoxin were compatible with those obtained with IgM antibodies.

3. The level of this natural antibody in 101 individual sera was examined. Titers ranging from 10 to about 600 LD50 units/ml were found. On the average 93.4 units/ml were present.

4. There was a relationship between blood group and antibody titer. The mean titers of groups O and A individuals were higher than those of groups B and AB individuals. This would indicate an antigenic cross‐reactivity between the B blood group antigen and antigen (s) on the ascites tumor cell.

5. Guinea‐pig serum could replace human complement in the titration of the natural cytotoxic antibody but was much less effective than human complement.
Studies on a naturally occurring human antibody active against mouse landschutz ascites tumor cells: II. Identification of the antibody as igm and its partial purification
Authors: Laskov R. , Simon E. , Ram D. , Gross J.
Published: February 2007

1. The cytotoxic antibody in normal human serum, active against mouse tumor cells, was identified as a 19S macroglobulin by means of Sephadex gel filtration, DEAE‐cellulose chromatography and density‐gradient centrifugation procedures.

2. A purified IgM fraction was isolated from normal human serum. The cytotoxic activity of this fraction, as tested against mouse tumor cells, was enriched 20–80 times over that of the unfractionated serum. The purified IgM showed mainly one precipitin line on immunoelectrophoretic analysis. In the ultracentrifuge the 19S peak comprised about 85% of the total protein.
Mechanism of preventive immunization with the aid of rauscher virus culture having an attenuated leukemogenic potential
Authors: Youn Jung Koo , Barski Georges , Barbieri Dominique
Published: February 2007

The experiments reported here were aimed at elucidating mechanisms involved in the immunization of mice against Rauscher leukemia with the aid of in vitro cultivated cells chronically infected with the “attenuated” Rauscher virus.

BALB/c mice were implanted intraperitoneally with Algire‐type, 0.45 μ porosity, Millipore chambers containing Rauscher‐virus‐infected cells. The animals developed leukemia when the cells in the chambers originated from leukemic spleens producing the virulent virus. On the contrary, when the cells in the chambers originated from cultures producing “attenuated” virus, the mice developed no disease but firm and specific immunity.

Cytotoxic tests performed with anti‐viral sera, obtained in hyperimmunized mice or monkeys, showed that the density of viral antigen was of the same order of magnitude on the surface of cells infected in vivo with the highly leukemogenic virus (leukemic spleen cells), as on cells infected in vitro and showing a moderately or highly attenuated leukemogenic potential. These data were fairly concordant with the results of electron microscopic examinations of the corresponding cell preparations for the presence of type C and A virus particles, which were equally abundant in both cases.

In addition to the neutralization of the virus by circulating anti‐viral antibodies, other mechanisms seem to be operating in animals vaccinated with the in vitro virus cultures. It appears that these animals were protected not only against challenge with the virulent virus but also against inoculation with leukemic cells. On the other hand, immunity produced by this type of vaccination could be efficiently transmitted by transfer of lymphoid cells from immunized donors to intact recipient animals even if these animals had no detectable anti‐viral antibodies when they were challenged with the virulent virus.

In conclusion, the mechanism of immunization with the aid of “attenuated” Rauscher virus cultures is of a complex nature. It is conditioned on the one hand by the production of circulating anti‐viral antibodies induced by the in vitro “attenuated” cultured virus, antigenically similar or identical to the “virulent” virus; on the other hand, one has to envisage an immunological mechanism of a cellular type which can be transferred by sensitized lymphoid cells and which may be induced by a cellular neoantigen common to the in vitro infected cell cultures and the leukemic cells.
Induction of thymidine−3h incorporation in multinucleated myotubes by rous sarcoma virus
Authors: Lee H. H. , Kaighn M. E. , Ebert J. D.
Published: February 2007

During the differentiation of skeletal muscle, mononucleated myoblasts fuse to form multinucleated myotubes. After fusion, both DNA synthesis and nuclear division cease. When clones of chick embryonic leg muscle consisting of both myoblasts and myotubes are infected with Rous sarcoma virus, DNA synthesis (as measured by thymidine‐3H incorporation) is induced in the nuclei of myotubes within 24 hours. On the other hand, nuclear division is not reactivated. These findings indicate that the restriction of DNA synthesis which attends the formation of myotubes is not irreversible since RSV, an RNA virus, reactivates DNA synthesis in mature myotubes.
Viral inclusions and other cytoplasmic components in a leydig cell murine tumor: An electron microscopic study
Authors: Pourreau‐Schneider Natalie , Stephens Robert J. , Gardner William U.
Published: February 2007

Cytoplasmic inclusion bodies which were clearly visible under light microscopy have recently been described in estrogen‐induced testicular interstitial cell tumors of mice. An ultrastructural study has revealed that the inclusions were formed of considerable numbers of type A virus particles which measured approximately 76 mμ in external diameter. Despite the abundance of intracytoplasmic viral particles, there was no sign of extracellular release or budding of mature particles from cellular membranes. Among the unusual cytoplasmic components of the tumor cells were bundles of filaments with a wavy appearance and a distinctive cross‐sectional pattern. These fibrillar structures may be a cellular manifestation of the presence of virus. In discussion, the inclusions of the testicular intestitial cell tumors are compared to inclusions found in other murine tumors.
Cultivation and fine structure of virus‐bearing lymphoblasts from a second new guinea burkitt lymphoma: Establishment of sublines with unusual cultural properties
Authors: Pope J. H. , Achong B. G. , Epstein M. A.
Published: February 2007

Two sublines of cells (QIMR‐AMB/1 and QIMR‐AMB/2) were established from a New Guinea Burkitt lymphoma. In contrast to previously described lines of cultured Burkitt lymphoma cells, there was a first phase of active proliferation of lymphoblasts completely dependent on an autologous fibroblast moiety of the cultures. In a second phase, lymphoblasts able to grow independently in suspension appeared at 8–10 weeks and gradually completely repopulated the cultures. Cytological and electron microscope studies showed that the lymphoid cells of the first phase resembled other cultured Burkitt lymphoblasts, and that the cells characteristic of the second phase were somewhat less differentiated. A herpes‐type virus, not transmissible in various tissue cultures or in mice, was detected by electron microscopy in some of the cells.
Studies on the biology of the mycoplasma‐induced “stimulation” of BHK21‐c13 cells
Authors: Russell W. C. , Niven Janet S. F. , Berman L. D.
Published: February 2007

Further investigations on the action of mycoplasmas on BHK21‐C13 cells are described. In addition to the already recorded alterations in cellular morphology, ability to form colonies in soft agar and changes in cellular nucleic acid metabolism, it has been found that the mycoplasma‐infected cells and the altered cells (in which no mycoplasmas could be detected) have an increased plating efficiency and an increased tumorigenicity. However, tumours produced by the altered (BHK21‐Mf) cells failed to show either mycoplasmas or foreign cellular antigens and their morphology is essentially similar to tumours produced by the control BHK21‐C13 cells. Analysis of the BHK21‐C13 cell—mycoplasma interaction has led to the conclusion that the phenomenon is not directly comparable to the usual type of neoplastic transformation produced by oncogenic viruses. However, implications of results such as these, obtained with the inherently neoplastic BHK21 cell line, must always be interpreted with caution.
Studies on cross‐resistance to degranol‐ and dibromodulcitol‐resistant yoshida tumours
Authors: Gáti Éva
Published: February 2007

Cross‐resistance studies were carried out on a series of sugar alcohol derivatives substituted in positions 1 and 6 with various functional groups. Yoshida ascites tumours resistant to Dibromodulcitol as well as to Degranol proved to be cross‐resistant to Degranol, Dibromodulcitol, Dibromomannitol and Mannitolmyleran. Myleran and Vinblastine sulphate inhibited the growth of the sensitive and resistant tumours to the same degree. Experiments with bilaterally growing solid forms of these tumours yielded the same result. The relationship between the chemical structure and the mechanism of this cross resistance is discussed.
Murine sarcoma virus (harvey): Characteristics of focus formation in mouse embryo cell cultures, and virus production by hamster tumor by cells
Authors: Bassin R. H. , Simons P. J. , Chesterman F. C. , Harvey J. J.
Published: February 2007

Titrations of the Harvey isolate of murine sarcoma virus (MSV) in mouse embryo cells indicated that infection of a cell with MSV alone might not be sufficient to induce focus formation. Addition of high concentrations of Moloney leukemia virus to diluted MSV preparations resulted in an increased number of foci, consistent with the hypothesis that Moloney leukemia virus can act as a helper for defective MSV (Harvey).

A transplantable hamster tumor line was established by inoculation of fragments from an MSV‐induced mouse tumor into newborn hamsters, followed by repeated passage in adult hamsters. Tumor tissue from the 25th hamster transplant generation of this tumor line was used to establish a cell line — “B‐34” — in culture. B‐34 cells elaborated a filtrable agent which produced sarcomas and other lesions characteristic of MSV when inoculated into newborn hamsters, but which did not produce any observable pathological changes when inoculated into newborn mice. However, mixed cultures of B‐34 cells and normal mouse embryo cells, when superinfected with Moloney leukemia virus, released MSV infective for both mice and mouse embryo cell cultures.
Ultrastructure of a mouse sarcoma in its solid, enzymatically dissociated and ascitic forms
Authors: Boeryd B. , Lundin P. M. , Norrby K. , Schelin U.
Published: February 2007

Ascites tumor cells differed from cells of the solid tumor in possessing filamentous structures in the marginal parts of the cytoplasm, in demarcated juxtanuclear areas and in uniform microvillous surface protrusions — “microspikes”. In free cells, dissociated from the solid tumor by trypsin and deoxyribonuclease, filamentous structures and microspikes of the same kind as in ascites tumor cells appeared regularly, evidently as an adaptation to the free‐cell state. In ascites tumor cells, exposure to crude trypsin led to detachment of microspikes and occasionally of larger cytoplasmic buds. Similar effects, although less frequent, occurred after treatment with crystalline trypsin.
Report on the workshop on virus induction by cell association
Authors: Svoboda Jan , Simkovic Dusan , Koprowski Hilary
Published: February 2007

According to the decision reached at the meeting of the Committee of Virology and Immunology of the UICC held at Sukhumi, USSR, in May, 1965, a Workshop on Virus Induction by Cell Association was held at The Wistar Institute on November 2 and 3, 1967. The Workshop was attended by scientists from the following countries: Canada, Czechoslovakia, France, Germany, Japan, Sweden, United Kingdom, United States and USSR.

The subject of the first session was “The Investigation of Rous Sarcoma Virus”.
Effect of reticuloendothelial system stimulation on resistance to rous sarcoma virus infection in chicks
Authors: Bliznakov Emile G.
Published: February 2007

By using a non‐toxic reticuloendothelial system stimulant, lipid‐Restim, derived from shark livers, we were able to demonstrate the following effects on growing Rous sarcoma tumors in young chicks. Prechallenge Restim treatment: Significant reduction of the percentage of chicks with tumors and prolongation of the latent period resulted from combined administration of Restim and specific antiserum. Postchallenge Restim treatment: The mortality data indicated that there was a significant increase in survival time and survival rate. Complete regressions

The term “regression” is used in this paper to mean complete macroscopical disappearance of the primary tumor at the site of inoculation of the virus.

occurred in a significant number of the Restim‐treated chicks compared to the controls. Possible explanations of these findings are discussed.
Growth of the SV40‐ADENO 7 hybrid virus in human diploid cells
Authors: Kutinová Luda , Vonka V.
Published: February 2007

The reproduction of SV40‐adeno 7 hybrid virus (SP 2) was studied in a human diploid cell strain (LEP). Both components of the hybrid virus, i.e. the true adeno 7 and the defective PARA carrying incomplete SV40 genome, gew well in this system. Their final titres were comparable to those observed in green monkey kidney (GMK) cells. Investigation of the interaction between adeno 7 and PARA in LEP cells, including the examination of plaque‐derived virus lines, revealed that in this system the adeno 7 virus grew without the helper effect of PARA; moreover, the presence of PARA did not significantly influence the growth characteristics of adeno 7 in LEP cells. PARA, although present in some preparations of SP 2 virus in quantities exceeding adeno 7, were found to be defective in LEP cells as well as in GMK cells. Their presence and titre in different SP 2 virus lines derived from LEP cells were dependent on the multiplicity of infection.
Occurrence of fetoprotein in patients with neoplasms and non‐neoplastic diseases
Authors: Masopust J. , Kithier K. , Rádl J. , Koutecký J. , Kotál L.
Published: February 2007

Sera from 248 patients, children and adults with various tumors, and from 484 patients with different non‐tumorous diseases, were examined for the presence of fetoprotein by immunochemical methods and specific anti‐fetal protein antiserum absorbed with serum of adult individuals. The results show that fetoprotein appears in two types of tumors only: 1) in hepatocellular carcinoma, and 2) in malignant undifferentiated teratoma. In other types of neoplasms including embryonal tumors composed of more or less differentiated tissue, as well as in cases of nephroblastoma, sympathicoblastoma, chorionepithelioma and dysgerminoma, fetoprotein was not detected in any patient. Fetoprotein can occur in the first year of life in some patients suffering from hepatitis or some other liver disease. However, its concentration is low and it has a tendency to disappear with the regression of the disease. Fetoprotein was not detected, however, in patients suffering from non‐malignant diseases, including hepatitis, after the first year of life.
The effect of halogenated nucleosides on the sensitivity of a mouse lymphoma P388F TO X‐rays and methyl methanesulphonate
Authors: Fox Margaret
Published: February 2007

Populations of the P388F mouse lymphoma were sensitized to the effects of X‐rays by prolonged culture in non‐toxic doses of 5‐iodo‐2'‐deoxyuridine and 5‐bromo‐2'‐deoxyuridine. A marked decrease in the ability of analogue‐exposed cells to recover from fractionated doses of X‐rays was found. Thus the mechanism of sensitization may be related to inhibition of repair mechanisms. Replicate cultures of the same populations did not show an increase in sensitivity to the monofunctional alkylating agent methyl methanesulphonate (MMS), which suggests that damage by X‐rays and MMS may be by different mechanisms in the cell line. The results would also suggest that the alkylation of DNA by MMS is not the only cytotoxic effect of this drug.
UICC standard reference samples of asbestos
Authors: Timbrell V. , Gibson J. C. , Webster I.
Published: February 2007

ÉCHANTILLONS‐TYPES D'AMIANTE DE L'UICC

A la suite des recommandations faites en 1964 par le Groupe de travail „amiante et cancer”︁ de l'UICC et dont l'application avait été examinée par un Comité spécial en 1965, des échantillons‐étalons des cinq principaux types d'amiante ont été préparés par des chercheurs d'Afrique du Sud et du Royaume‐Uni, avec l'aide des entreprises minières intéressées de divers pays.

Plusieurs laboratoires en étudient actuellement les propriétés physiques et chimiques. Les échantillons (en sachets de plastique de 500 g ou moins) peuvent ětre obtenus sur demande à la Pneumoconiosis Research Unit, Johannesburg, Afrique de Sud, ou à la P. R. U. de Penarth, Royaume‐Uni.
Iron‐dextran induction of distant tumours in mice
Authors: Langvad E.
Published: February 2007

The systemic carcinogenicity of iron‐dextran has been investigated after single and repeated injections of Imferon in mice and rats. Systemic iron deposits induced by irondextran resulted in a stepwise development of reticulosarcomas. Such a histologic reaction, however, was not seen in relation to iron deposits following iron‐carbohydrate complex (Intrafer) administration. Distant tumours arising in the lymphoreticular structures showed a uniform latency in test and control mice, while tumours of other origin showed a prolonged latency as compared to such tumours in control animals. It is suggested, therefore, that iron‐dextran may act as a co‐carcinogenic factor in the case of lymphoreticular neoplasia, increasing host susceptibility to the oncogenic virus presumably present in both control and test animals. The non‐lymphoreticular distant and local tumours may stem from a different and direct carcinogenic action of iron since these tumours showed a prolonged latency and were seen after the administration of either iron‐dextran or iron‐carbohydrate complex.

The results indicate an inconclusive dose‐response relationship, though no significant difference was found between tumour yield in the larger groups receiving 500 and 25 mg Fe…/kg body weight, the latter dose being within the therapeutic level on a comparative weight basis.
Pathogenesis of rous sarcoma virus in the chick embryo with particular reference to vascular lesions
Authors: Coates H. , Borsos T. , Foard M. , Bang F. B.
Published: February 2007

1. Growth of strains of Rous sarcoma virus on the chorio‐allantoic membrane continues throughout the embryo's development, with some decrease in the rate of growth at the end. Susceptibility of the chorio‐allantoic membrane, as measured by the total number of lesions following a standard inoculum, was greatest at 11 to 13 days of incubation. The proportion of vascular pocks of the membrane was however much higher in embryos inoculated at 7 or 8 days of incubation.

Growth of virus in the chick embryo liver after intravenous inoculation was also continuous throughout incubation. Age of susceptibility, again measured by number of lesions, was however greatest at 8 to 10 days.

Examination of vascular lesions in the living embryo, and study of whole mounts stained by periodic acid‐Schiff method as well as of histological sections, all indicated that the vascular lesion was at least predominantly a localized neoplasm of the vascular endothelium. The early presence of PAS‐positive cells in the developing pock was demonstrated, an observation hitherto limited to tissue culture.

The presence of antibody to Rous virus in the yolk of the embryo was correlated with a decrease of vascular lesions following inoculation of 13‐day embryos but not ofj I‐day embryos.

Following intravenous inoculation, virus was probably limited to the initial area of infection during the first few days, but viremia was irregularly demonstrable from 3 days on.

In the discussion it is emphasized that tumors of the embryo or the chicken provoked by the Rous virus are primarily tumors of tissues derived from the mesoderm. This includes the capacity to cause vascular lesions. The production of avion lymphomatosis may well be an exception, but since the lymphatic tissue has not been clearly demonstrated to be of ectodermal origin, this remains an open question. Virus growth and tissue culture ‘ transformation ’ do occur in a variety of tissues.
Immunological study of leukemias in bald mice
Authors: de Pirosky Rosa Rabinovich
Published: February 2007

A study of the antigenic relationship between four leukemias in the BALB strain has been carried out. These included a spontaneous leukemia and three induced by different exogenous agents such as Sarcoma 180, 32P, and human neoplastic tissue.

Antisera were obtained by allogeneic hyperimmunization in Rockland inbred mice using fresh homogenates of BALB leukemic spleen and mesenteric lymph nodes. The four antisera with hemagglutinating titers between 1/1,280 and 1/5,120 and cytotoxic titers between 1/160 and 1/320, were absorbed by normal BALB cells until the titers fell below 1/10.

These absorbed antisera possessed neutralizing activity against fresh leukemic cells, as demonstrated in tests with live challenges. However each antiserum proved to be active against all four leukemias while each of the leukemias could absorb the neutralizing activity of any antisera.

These experiments only allowed the detection of one antigen in the four leukemias studied, no antigenic difference being observed among them by this technique.

Taking into account the fact that the BALB strain of this laboratory has a spontaneous leukemia incidence of 15%, these results suggest that the exogenous agents which induced three of these leukemias acted by triggering a latent leukemogenic process.
Conversion Cellulaire Provoquée in vitro par le Virus du Sarcome Murin (Moloney). Analyse de la Courbe Dose‐Réponse
Authors: Bernard C. , Guillemain B. , Peries J. , Boiron M.
Published: February 2007

An analysis of mouse sarcoma virus (MSV, Moloney strain) titration curves, based on the focus‐forming activity described by Hartley and Rowe, confirms that Moloney leukaemia virus (MLV) acts as a „helper”︁ of MSV for focus initiation.

However, viral stocks also seem to contain particles capable of initiating foci without the aid of MLV, as demonstrated by the linear relationship between the dilution and the number of foci when high dilutions were used.

The possible application of this method for titrating MSV is discussed and some data are given concerning the origin of the virus (tumours or tissue culture supernatants) and the type of reactive cells.
Polyoma virus replication in ascitic cells
Authors: Nordenskjöld Bo
Published: February 2007

Several ascitic tumors have been tested for polyoma sensitivity.

Three tumors, one methylcholanthrene‐induced and two polyoma‐virus‐induced, were demonstrated to be sensitive to polyoma virus as judged by plaque titration, hemagglutination and fluorescent antibody assay.

These determinants were correlated with the number of surviving cells and appearance of antiviral antibodies. The amount of virus produced and the number of infected cells found increased exponentially to reach a plateau about 50–100 hr post infection, after which the two respective counts either remained stationary or proceeded to fall.

A reduction in virus recovery was paralleled by the appearance of antiviral antibodies in the serum. The total number of cells present in the peritoneal cavity remained stationary, or dropped after polyoma infection, suggesting the possibility that polyoma virus acted as an oncolytic agent.

The high number of infected cells obtained at optimal times after polyoma exposure suggests the possibility that ascites tumors can be a useful routine tool for biochemical and other experiments where an abundant source of polyoma‐infected cells is needed.
Chromosome studies on cultured lymphoblast cell lines from cases of new guinea burkitt lymphoma, myeloblastic and lymphoblastic leukaemia and infectious mononucleosis
Authors: Tomkins G. A.
Published: February 2007

Chromosome analysis of three lymphoblast cell lines from New Guinea Burkitt lymphoma (QIMR‐GOR, QIMR‐AMB/1 and AMB/2), three lymphoblast cell lines from infectious mononucleosis (QIMR‐DAR, QIMR‐STE and QIMR‐GOE) and two lymphoblast cell lines from leukaemia (QIMR‐WIL and QIMR‐FIN) showed abnormalities associated with Group A, C, and G chromosomes. Each cell line contained diploid and near diploid cells. Some of the cell lines also contained pseudodiploid cells. Extra Group C or Group G chromosomes were found in a proportion of cells from some of the cell lines. Abnormal Group A chromosomes were also found. However, no one abnormality could confidently be assigned to a specific source of origin of the cell line studied.
Auto‐antibody to 7,12‐dimethylbenz(A)anthracene‐induced leukemic cells in rats as detected by immune adherence
Authors: Yoshida Takato O. , Imai Kuniyuki , Sugiyama Taketoshi
Published: February 2007

Sixteen Long‐Evans rats with leukemias induced by 7,12‐dimethylbenz(a)anthracene were studied for evidence of naturally occurring immunologic responses to their own leukemic cells with an immune adherence hemagglutination technique which was designed to detect fresh serum auto‐antibodies to the membrane of the leukemic cells. Auto‐antibodies to the cell membranes were found in 14 out of 16 rats, but were not demonstrable in the other two rats. Autochthonous thymus cells used as controls did not show positive immune adherence hemagglutination reactions with their own sera, nor did the leukemic cells show positive reactions with the pooled normal rat serum. These findings suggest a possibility that the leukemic rats are able to produce humoral antibodies against membrane‐specific antigens of autochthonous leukemic cells.
Carcinogenesis by avian sarcoma viruses. X. The decreased requirement for insulin‐replaceable activity in serum for cell multiplication
Authors: Temin Howard M.
Published: February 2007

Experiments have been carried out to explain the decreased requirement for specific factor (s) in serum necessary for multiplication of chicken embryo fibroblasts infected and converted by avian sarcoma viruses. It has been shown that both uninfected and converted chicken cells in the G1 stage of the cell cycle are stimulated by one unit (molecule) of serum factor or insulin to continue through the cell cycle. In the absence of serum or insulin, uninfected cells continue to the next G1 stage and stop; converted cells continue through further divisions. Therefore, when the amount of serum is limiting for cell multiplication, the converted cells multiply more than uninfected cells.
Cytokinetics of the Krebs 2 carcinoma. I. Its effect on the cell population kinetics of duodenal crypt proliferation
Authors: Schmeer A. C.
Published: February 2007

The effect of the Krebs 2 transplantable solid carcinoma upon the cell cycle of the duodenal cryptal progenitor population has been determined by thymidine‐3H uptake and radioautography. A single pulse label of tritiated thymidine was injected into each of 183 CF1 mice with a 4‐day‐old solid tumor. The animals were then serially killed from 15 min to 24 hr later. Data were collected from a curve describing the rate of appearance and disappearance of labelled mitoses in the tumor and duodenum. An estimate of the time intervals of G1, S, M and G2 was calculated by two different methods and compared. The turnover rate of the cryptal progenitor population from the tumor‐bearing animals was found to be essentially similar to that of the control cryptal population of the non‐tumor‐bearing mice. The cytokinetics of the cell cycle of the Krebs 2 carcinoma is also reported. The methods described for collecting data on the turnover rate of tissues of both tumor‐bearing and non‐tumor‐bearing animals can be utilized to determine what effect growth‐promoting and growth‐inhibiting agents may have on the proliferation of normal progenitor compartments while at the same time measuring the effect of such drugs on the cytokinetics of an experimental tumor.
The influence of sex upon the development of friend virus leukaemia
Authors: Gillespie A. V. , Rowson K. E. K.
Published: February 2007

The morbidity and mortality in Parkes mice of both sexes following the injection of various doses of Friend leukaemia virus have been studied. Individual mice were tested for the presence of viraemia and for neutralizing and tumour‐specific cytotoxic antibodies. The principal findings were: (1) more rapid death among the female than the male mice; (2) the fact that, among the mice with splenomegaly, those with viraemia are usually male while those with neutralizing or cytotoxic antibodies are usually female; (3) the presence of circulating cytotoxic antibody in many mice with splenomegaly. It is hypothesized that female mice with Friend virus leukaemia are considerably superior to males in antibody‐producing capacity and that the former owe their more rapid death to tissue damage caused by an immunological response to the virus or cellular neo‐antigen.
The sensitivity of a yoshida sarcoma to methylene dimethane sulphonate
Authors: Fox Brian W.
Published: February 2007

The action of methylene dimethane sulphonate on the growth rate of the Yoshida sarcoma in rats is described. 1) The tumour, even when established for 12 to 14 days, is unusually sensitive to this alkylating agent and approximately 90% complete cures can be obtained. 2) About 10% of the treated tumours recur and, on retransplantation to new animals, show a marked resistance to the drug. The growth curves of the original and resistant lines, both unilaterally and bilaterally transplanted, following treatment by the drug, are described. 3) Animals in which the original tumour had completely regressed failed to accept a reimplantation of the original or of a resistant tumour.

Comparable doses of myleran failed to produce complete regression of the tumour when administered 10 days after transplantation and the level of inhibition was much less than with methylene dimethane sulphonate. Cross‐resistance with triethylene melamine was observed.
Immunological studies on mouse mammary tumors. IV. Extraction and solubilization of transplantation antigen of mouse mammary tumor
Authors: Irie Reiko Furuse , Nishioka Kusuya , Tachibana Takehiko , Takeuchi Shoshichi
Published: February 2007

Antigens present in mouse mammary tumor MM2 reacting with tumor‐specific antibodies were extracted with 0.2% deoxycholate. After the removal of deoxycholate by dialysis, most antigens were precipitated by centrifugation at 105,000 × g for 60 min. Hyperimmunization of C3H/He mice with these antigens induced heightened resistance against MM2. Antibodies appeared in the serum after a booster injection of deoxycholate extract of tumor cells was given. Antigens were solubilized from deoxycholate extract with distilled water. Purified soluble antigen inhibited the neutralization activity of the tumor‐specific antibody to MM2 tumor. From these observations, it is concluded that transplantation antigens of isografted mammary tumors in C3H/He mice are present in deoxycholate extracts of MM2 tumor.
Quantitative studies on the malignant transformation of mouse prostate cells by carcinogenic hydrocarbons in vitro
Authors: Chen T. T. , Heidelberger Charles
Published: February 2007

A quantitative system for producing malignant transformation of adult C3H mouse ventral prostate cells in culture with carcinogenic hydrocarbons has been developed. Aneuploid cell lines derived from mouse prostate are plated at a low density on a feeder layer and treated with various hydrocarbons for different lengths of time; other dishes are treated with 0.5% dimethyl sulfoxide (the solvent for the hydrocarbons) as controls. After 8 days some dishes are fixed and stained and the colonies are counted for total plating efficiency. Two weeks later other dishes are also fixed and stained. In the DMSO controls, the cells remain as a monolayer. In the carcinogen‐treated dishes, piled‐up multilayered colonies are seen and their frequency is scored. It has been shown that each of such piled‐up colonies gives rise to fibrosarcomas in mice, whereas the cells obtained from the monolayer areas of treated dishes do not cause tumors. Thus, these piled‐up colonies represent malignant transformation, under conditions where no spontaneous malignant transformation occurs. There is an excellent quantitative correlation between the carcinogenic activities of eight hydrocarbons and the transformation frequencies they produce in this system. Malignant transformation has been produced by treatment with methylcholanthrene for only one day. The acquisition of heat sensitivity is an early consequence of malignant transformation in this system.
Decreased interferon sensitivity and production in cells transformed by sv40 and other oncogenic agents
Authors: Brailovsky C. A. , Berman L. D. , Chany C. H.
Published: February 2007

From a pool of primary rat embryo fibroblast cells, three lines—two SV40‐infected and one control—were serially propagated. Prior to unequivocal morphological evidence of transformation, increased sensitivity to vesicular stomatitis virus (VSV) was found in the two SV40‐infected lines when compared to the control line. The increased VSV sensitivity of the transformed cells seems to be due to a diminished production of and sensitivity to interferon, and not to differences in adsorption. When a collection of diverse transformed cell lines were also compared with arbitrarily selected control cell populations, the majority of the transformed cells also exhibited enhanced VSV sensitivity. Lines transformed by methylcholanthrene also featured this property. The data suggest that diminished sensitivity to and production of interferon is an early consequence of infection by oncogenic viruses, and a property that persists in many lines of transformed cells.
Induction experiments with adenovirus and polyoma virus transformed cell lines
Authors: Burns William H. , Black Paul H.
Published: February 2007

Techniques used successfully in inducing SV40‐transformed cells to produce infectious SV40 were employed in an attempt to induce cells transformed by other oncogenic DNA viruses, adenoviruses 2 and 12 and polyoma virus. These techniques included cocultivation and fusion of transformed cells with indicator cells, and mitomycin C treatment of these heterokaryons and of transformed cells. In addition, prior to induction experiments, some cell lines were passaged through animals or in the presence of BUdR in an effort to enhance their inducibility. All attempts to induce these transformed cells were unsuccessful. It is concluded from this study that the polyoma and adenovirus genomes, if present in their entirety in cells transformed with these viruses, are not as reactivable as is the SV40 genome in SV40‐transformed cells.
In vitro demonstration of tumor‐specific antigens in spontaneous mammary tumors of mice
Authors: Heppner G. H. , Pierce G.
Published: February 2007

The colony‐inhibition test has been used to demonstrate cellular immunity against spontaneous murine mammary tumors, both in autochthonous, mammary tumor virus (MTV)‐carrying BALB/cfC3H and in immunized, MTV‐free, BALB/c mice. Immunity could be demonstrated in nearly all cases against a mammary tumor with lymph‐node cells from mice which had experienced that tumor.

One of eight tumors tested with lymph‐node cells from BALB/cfC3H mice which had spontaneously developed mammary tumors showed evidence of immunological cross‐reactivity, while seven of thirteen tumors did so when tested with immune cells from MTV‐free BALB/c mice. The data, therefore, indicate the presence of at least two types of tumor‐specific antigen (s) in mouse mammary tumors — a common one and an antigen specific for each neoplasm.
The occurrence of tumours in F1, F2, and F3 descendants of pregnant mice injected with 7,12‐dimethylbenz(A) anthracene
Authors: Tomatis L. , Goodall C. M.
Published: February 2007

Pregnant MA mice were injected intraperitoneally with 400 micrograms of 7,12‐Dimethylbenz(a)anthracene in olive oil during the last stages of pregnancy. The genetic design of the experiment included the follow‐up of the descendants for three consecutive generations and the cross‐mating between the F1 descendants of treated mothers with descendants of untreated controls. An increased incidence of tumours was observed in the female F1 and F2 descendants and the female F2f descendants (cross‐mating of F1 female descendants from a treated mother and male descendants from an untreated control). The tumours were observed in animals dying at a late age which approximately corresponded to the age when spontaneous tumours were observed in control animals. The most frequent types of tumours were the same as observed in the control animals, together with a handful of rarely observed tumours. In the F1 and F2 male descendants the tumour incidence was higher than in control animals but the difference was statistically not significant (binomial test). No significant increase in tumour incidence was observed in the F3 and F2m descendants (cross‐mating of F1 male descendants from treated mothers with female descendants from untreated controls). While the mice of F1 generation were directly exposed to small amounts of the chemical carcinogen via the mothers' milk and excreta, and possibly through the placenta, it seems unlikely that DMBA as such was transmitted to the F2 descendants.