bluuebunny/crossref_metadata_2025_split huggingface dataset:
Agglutination reactions of spontaneous canine tumour cells, induced by concanavalin a, demonstrated by an isotopic assay
Authors: Betton G. R. 
Published: February 2007

AbstractQuantitative assessment of the agglutination of 51Cr labelled canine cell suspensions to canine kidney cell monolayers has been performed over a range of concanavalin A concentrations. Agglutination was observed with all cell cultures tested, comprising four spontaneous canine melanomas, two canine mammary carcinomas, a benign mammary tumour and a contact‐inhibited kidney cell line. The melanomas tested showed strong specific inhibition of concanavalin A agglutination by 10−2 M α‐methyl‐D‐glucopyranoside. Inhibition of agglutination of mammary tumour and kidney cells was weaker and less specific. Agglutination was inhibited at 4°C. Reduced agglutination to glutaraldehyde‐fixed monolayers was observed in the case of mammary tumours but was absent when contact‐inhibited kidney cells were tested. The specificity of the reaction for transformed cells and the parameters involved are discussed.
Mast cells and tumor angiogenesis
Authors: Kessler David A. , Langer Robert S. , Pless Naomi A. , Folkman Judah 
Published: February 2007

AbstractTumor angiogenesis factor (TAF) elicits a strong vasoproliferative response when implanted upon the chorioallantoic membrane (CAM) of the chick embryo. This response is first observed stereomicroscopically 2–3 days after implantation. A 40‐fold increase in mast cell density is observed within the vicinity of this implant by 24 h. Mast cells that have been isolated from retired breeder Sprague‐Dawley rats fail to evoke a vascular reaction when implanted on the CAM. An intermediate role for the mast cell in tumor angiogenesis is suggested.
Histologic specificity of the effect of age at birth of first child on breast cancer risk
Authors: Morrison Alan S. 
Published: February 2007

AbstractSlides of 531 breast cancers from Glamorgan, Wales, were classified according to the presence or absence of each of three histologic characteristics: stromal infiltration by linear strands of tumor cells, areas of intraductal carcinoma, and areas of lobular carcinoma in situ. The proportion of tumors with each of these characteristics was positively associated with age at first child‐birth. Increasing age at first birth had a strong positive effect on the incidence risk of tumors with any of these features, but only a small effect on risk of tumors with none. For porous women, the rate of breast cancer with or without linear strands, with or without areas of intraductal cancer, and without areas of lobular carcinoma in situ was lower than for nulliparous women. Parity appeared not to reduce the risk of tumors with areas of lobular carcinoma in situ.
Oncornavirus‐like particles in malignant melanoma and control biopsies
Authors: Parsons P. G. , Klucis E. , Goss P. D. , Pope J. H. , Little J. H. , Davis N. C. 
Published: February 2007

AbstractTests for the presence of oncornavirus‐like particles in human biopsies were made by the Spiegelman simultaneous assay for 70S RNA and RNA‐dependent DNA polymerase and by detection of 600–900S particles, incorporating 3H‐uridine, produced by cultured biopsy cells. Thirty‐one malignant melanoma biopsies from 29 patients were studied. Using the simultaneous assay, evidence of virus‐like particles was found in 15/26 (58%) of melanoma biopsies, 0/3 naevi pool, 1/4 samples of skin adjacent to melanoma, 0/3 samples of normal adult skin and 0/3 prepuces. The velocity sedimentation technique was shown to be a useful screening test for oncornaviruses in studies of two virus‐producing mouse cell lines (TKL‐5 and WEHI‐22), and was positive with 7/9 melanoma biopsies. Overall, these results are compatible with the earlier findings of similar virus‐like particles in malignant melanoma cell lines, but the exact nature of the particles remains to be defined.
The immunospecificity of altered initial arrest patterns of circulating cancer cells in tumor‐bearing mice
Authors: Weiss L. , Glaves D. 
Published: February 2007

AbstractThe early arrest patterns of a methylcholanthrene‐induced fibrosarcoma were determined after injection of 125IUdR‐labelled cells into the systemic circulation of mice bearing transplanted lymphosarcomas, and of normal animals. Similar experiments were performed using radiolabelled lymphosarcoma cells and normal or fibrosarcoma‐bearing mice. The results showed that shifts in normal distribution patterns previously observed in tumor‐bearing animals injected with cells of the same type as that borne by the animal, were not detectable when cells of a different tumor type were injected. Peritoneal exudate cell migration inhibition assays showed little immunologic cross‐reactivity between the two tumors and, together with the results of the distribution studies, indicated that alterations of early arrest patterns in mice sensitized to their tumor is an immunologically specific phenomenon.
Membrane‐associated antigen from the SV40‐induced hamster fibrosarcoma, para‐7. I. Role in immune complex fcrmation and effector cell blockade
Authors: Prather Suzanne O. , Lausch Robert N. 
Published: February 2007

AbstractPARA‐7 membrane‐associated antigen was prepared by treatment of the tumor cells with PH 9.4 glycine buffer, or by concentration of spent cell culture medium. When admixed with sensitized effector cells, both preparations could specifically block cellular cytotoxicity for PARA‐7 target cells. Pretreatment of target cells with antigen did not result in blocking. Incubation of antigen extract with simian virus 40 (SV40) anti‐serum caused neutralization of antibody‐dependent cellular cytotoxicity (ADCC) with concomitant formation of a factor which blocked at the target cell level but not at the effector cell level. Serum from tumor‐bearing hamsters exhibited blocking characteristics comparable to those of the antigen‐SV40 antiserum preparation. Washing experiments indicated that PARA‐7 antigen was more efficient than PARA‐7 antigen‐antibody complexes in blocking cell‐mediated immunity in vitro. Material extracted from untransformed hamster embryo fibroblasts either by itself or when admixed with SV40 antiserum exhibited no significant blocking activity. These observations support the concept that loss of serum ADCC during progressive tumor growth is due to immune complex formation.
Leukaemias in BN/a and BN/b mice after prolonged treatment with antilymphocyte globulin
Authors: Szkudlarek Jerzy , Radzikowski Czeslaw , Czarnomska Alina , Dux Kazimierz , Bartoszewicz Wadysaw 
Published: February 2007

AbstractThe influence of prolonged treatment with anti‐lymphocyte globulin on tumour incidence in BN/a and BN/b mice was studied. One ALG sample appeared to be highly leukaemogenic in two independent experiments. All treated mice developed, after a short latency period, non‐thymic lymphomas with involvement of abdominal lymph nodes and spleen resulting in ascites. Three established ascites leukaemia cell lines were examined for the presence of MuLV. In all lines viral C‐type particles, soluble viral gs‐1 antigen and cell surface antigen related to Gross virus were demonstrated. The mechanism of induction of these tumours remains obscure. The hypothetical role of immunosuppression, stimulation of lymphoid cells and activation of leukaemogenic virus is discussed.
Leukemogenic activity of murine type C viruses after long‐term passage in vitro
Authors: Buchhagen Dorothy L. , Pincus Theodore , Stutman Osias , Fleissner Erwin 
Published: February 2007

AbstractCloned stocks of several murine leukemia viruses (MuLVs) were shown to be leukemogenic for susceptible mice after more than nine years of in vitro passaging in mouse embryo fibroblasts. Tissue culture‐grown Rauscher (R‐) MuLVs injected into newborn or young adult BALB/c mice induced lymphocytic leukemias in 100% of the animals beginning 80 days post‐inoculation. No erythroblastic leukemia was observed even after passaging the tissue‐culture‐grown R‐MuLVs twice through mice, indicating that the component responsible for that disease had been lost or attenuated during growth in fibroblasts. The tissue‐culture‐grown stock of Moloney (M‐) MuLVs likewise induced lymphocytic leukemias in 94% of injected newborn BALB/c mice, and the tissue culture‐grown Gross (G‐) MuLVs induced lymphocytic leukemias in 42% of injected newborn C3Hf mice. The host range and neutralization characteristics of viruses recovered from animals that became leukemic after injection with the tissue‐culture‐maintained MuLVs were found to be identical with those of the injected viruses. These data implicate the injected MuLVs in the induction of the leukemias and suggest that the capacity to induce the disease is stably inherited as part of the viral genome even in the absence of expression.
Chemical‐viral co‐carcinogenesis: Requirement for leukemia virus expression in accelerated transformation
Authors: Mishra Nirmal K. , Pant Kamala J. , Thomas Francina O. , Price Paul J. 
Published: February 2007

AbstractThe essential role of Rauscher leukemia virus (RLV) multiplication in viral—chemical co‐carcinogenesis was investigated by the use of ethidium bromide (EtBr) as an inhibitor of viral complementary DNA (cDNA) integration in the host genome. EtBr inhibited co‐carcinogenic transformation when present at the time of RLV inoculation but was ineffective when added to preinfected cells. Inhibitors of protein synthesis, puromycin and cyclohexamide also inhibited co‐carcinogenic transformation of chronically infected cells. Purified rat interferon used at a concentration which inhibited 85% of RLV production did not modify the course of co‐carcinogenic transformation. The implications of these observations in terms of the possible role of the virus‐specific protein(s) in the co‐carcinogenic process are discussed.
Reactivity of peripheral blood leukocytes against human foetal cells. II. Cytotoxic potential of preparations enriched or depleted of different leukocyte populations
Authors: Vose B. M. , Moore M. 
Published: February 2007

AbstractLeukocytes separated initially by Ficoll‐Triosil sedimentation from the peripheral blood of 62 healthy donors and 64 patients with a variety of cancers were tested for cytotoxicity against cells from a single human foetal lung, by means of a microplate technique based on visual enumeration of surviving target cells. Under these conditions cytotoxicity was primarily observed to be a function of the granulocyte content of the preparations, which was extremely variable (range 0–60%). When the influence of these cells was greatly diminished through depletion by adherence, residual cytotoxicity was still detectable in the majority of samples tested. Complete abrogation of this cytotoxicity by pretreatment with carrageenan implicated cells of the monocyte‐macrophage series, which persisted as a small minority (about 2%) in the already depleted effector cell populations. However some cytotoxicity could also be demonstrated in populations, purified by passage through columns containing nylon fibre or Degalan‐coated (human Ig‐anti Ig) beads, which consisted almost exclusively (about 98%) of lymphocytes, mainly of thymus (T)‐dependent type (⩾80%). Under these conditions and those in which T‐cells were concentrated by formation of spontaneous E rosettes, cytotoxicity appeared to decline with T cell enrichment, suggesting that the cytolytic effects were attributable to cells of the non‐T compartment which were present to a variable extent in the different T‐cell‐enriched populations. Although the absolute identity of these cells was not established, the experiments illustrate potential sources of non‐specific cytotoxicity among different effector cell populations against target cells expressing antigens to which the majority of leukocyte donors —in health or disease—were presumably non‐sensitized. As such these data have several implications for the interpretation of in vitro cytotoxicity tests against human neoplasms.
Detection of human c‐type “helper” viruses in human leukemic bone marrow with murine sarcoma virus‐transformed human and rat non‐producer cells
Authors: Nooter Kees , Bentvelzen Peter , Zurcher Chris , Rhim Johng 
Published: February 2007

AbstractBone‐marrow cells from two leukemic children were co‐cultivated with the canine thymus cell line A 7573. In early passages, C‐type oncornaviruses were released as detected by extracellular reverse transcriptase assay. Co‐cultivation of the infected canine cells with the non‐producing cell lines R‐970‐5 (human) or K‐NRK (rat) both transformed by Kirsten mouse sarcoma virus (MSV) yielded a new pseudotype of MSV that could transform rat embryo, rabbit SIRC and human kidney cells but not mouse embryo cells. The focus formation could be inhibited by an antiserum to the simian sarcoma virus but not by a serum directed against murine leukemia virus. A cell line derived from a focus of transformed cells became a high virus producer. By immunofluorescence it could be established that the virus is related to the simian sarcoma virus. It is concluded that the leukemic bone‐marrow cells produce a C‐type oncornavirus that can serve as a helper virus to the defective MSV.
Detection of early antigens in nuclei of cells infected with cytomegalovirus or herpes simplex virus type 1 and 2 by anti‐complement immunofluorescence, and use of a blocking assay to demonstrate their specificity
Authors: Giraldo G. , Beth E. , Hämmerling U. , Tarro G. , Kourilsky F. M. 
Published: February 2007

AbstractSkin fibroblasts exposed to cytosine arabinoside (Ara C) were infected with either cytomegalovirus (CMV) or herpes simplex virus (HSV) type 1 and 2. Herpesvirus‐determined early antigens (HV‐EA), detected by anti‐complement immunofluorescence (ACIF), occurred primarily in the nuclei, and the specificity of these results was established by an ACIF blocking reaction using F(ab')2 fragments of human and hyperimmune reference sera. Direct tests with selected sera and cross‐blocking experiments between early antigenic systems of CMV, HSV‐1 and the Epstein‐Barr virus (EBV) did not demonstrate common HV‐EA.
Development of hemangiosarcomas in B6C3F1 mice fed 2‐methyl‐1‐nitroanthraquinone
Authors: Krishna Murthy A. S. , Baker J. R. , Smith E. R. , Wade G. G. 
Published: February 2007

AbstractSubcutaneous hemangiosarcomas developed in 97% of 172 B6C3F1 mice of both sexes fed either 0.03% or 0.06% 2‐methyl‐1‐nitroanthraquinone in the diet. There was no significant relationship to dose or sex. In addition, similar vascular tumors occurred in the mesentery of 14 mice. 2‐Methyl‐1‐nitro‐anthraquinone is carcinogenic in B6C3F1 mice when given in food. One of 97 control mice had a splenic hemangiosarcoma.
Dna binding and its relationship to carcinogenesis by different polycyclic hydrocarbons
Authors: Huberman Eliezer , Sachs Leo 
Published: February 2007

AbstractFive different polycyclic hydrocarbons with different degrees of carcinogenicity in vivo were tested for their metabolism to water‐soluble products and their binding to DNA, RNA and protein in normal embryonic hamster and BHK cells. The compounds studied were 7,12‐dimethyl‐benz(a)anthracene, benzo(a)pyrene, 20‐methyl‐cholanthrene, dibenz(a,h)anthracene and dibenz‐(a,c)anthracene. All five compounds were metabolized to water‐soluble products in both types of cells and treatment of cells with aminophylline enhanced this metabolism. After and not before this enhancement of metabolism by aminophylline, there was a relationship between the degree of carcinogenicity and binding to DNA. There was no such relationship with binding to RNA or protein. The results, indicating a relationship between the degree of carcinogenicity and binding to DNA under appropriate conditions of metabolism, support the suggestion that DNA is the target for carcinogenesis by such carcinogens.
Long‐term administration of ddt or phenobarbital‐na in wistar rats
Authors: Rossiz Lorenzo , Ravera Marina , Repetti Giuliana , Santi Leonardo 
Published: February 2007

AbstractIn lifespan studies, outbred male and female Wistar rats were given either technical DDT mixed into the diet at a dose of 500 parts per million (ppm) or phenobarbital‐sodium dissolved in drinking water at a dose of 500 ppm. Liver‐cell tumors developed in treated animals but not in controls. The incidence of liver tumors was 45% in the DDT‐treated group and 44% in the phenobarbital‐sodium‐group. When evaluated by sex, DDT‐treated females and males had incidences of 56% and 35%, respectively, while in the phenobarbital‐sodium group, the respective incidences were 32% and 59% in females and males. These data show a varying susceptibility between the sexes, with regard to induction of liver‐cell tumors by the two compounds. In both treated groups, the number of nodular tumors per rat and the average size increased with age and were greater in females. None of these tumors had metastasized. Histologically, the liver tumors were nodular growths, which compressed surrounding parenchyma but did not infiltrate it. The total incidence of extrahepatic tumors was higher in controls than in treated animals. In this connection, we must mention the apparent, but not significant, reduction of adrenal tumors in treated rats compared to the controls.
Gross‐virus‐induced lymphoma in the rat. V. Natural cytotoxic cells are non‐t cells
Authors: Shellam G. R. 
Published: February 2007

AbstractThe cytotoxic cells from the spleens of normal rats, which lyse Gross‐virus‐induced lymphoma target cells in a short‐term 51Cr release test, are predominantly small to medium‐sized cells sedimentng at 4–5 mm/h as shown by velocity sedimentation analysis. Their cytotoxic activity is relatively resistant to γ‐radiation, 50% surviving 1,000 rads and 30% remaining after 5,000 rads, and to heat, since 20 min incubation at 48–51° C is required for its abolition. In these properties the natural killer (NK) cells are very similar to the cytotoxic T cells from tumour‐immune rats, and they share in addition a requirement for Ca++ ions for cytolysis. They differ in that they are non‐T cells as defined by their resistance to anti‐T‐cell antiserum and complement, and by their presence in T‐cell‐deprived rats. They lack detectable surface Ig, Fc receptors and phagocytic or adherence properties and belong therefore to that small proportion of lymphoid cells lacking the surface markers of T or B lymphocytes, as do the comparable NK cells of mice. Cytotoxicity appears to involve an autonomous, papain‐sensitive recognition structure on the surface of NK cells, rather than acquired cytophilic antibody operating through an antibody‐dependent mechanism.
Effects of ethylnitrosourea administration during pregnancy on three subsequent generations of bdvi rats
Authors: Tomatis L. , Ponomarkov V. , Turusov V. 
Published: February 2007

AbstractA single dose of 40 mg/kg of N‐nitrosoethylurea (ENU) was administered to BDVI rats on the 16th day of pregnancy. The first generation descendants (F1) were mated on a brother‐to‐sister system to produce a second generation (F2) which was then mated to produce a third generation. A high incidence of nervous tissue tumors and a few kidney tumours were observed in F1 descendants. A few nervous tissue tumours were observed in F3 but not in F2 descendants. These results partially confirm previous observations obtained with 7,12‐dimethylbenz(a)anthracene in mice and nitrosomethylurea in rats and indicate that prenatal exposure to a chemical carcinogen may result in an increased cancer risk which can persist for more than one generation.
Mouse mammary tumor virus production stimulated by hormones and polyamines in cells grown in semi‐synthetic in vitro conditions
Authors: Svec Juraj , Links Jan 
Published: February 2007

AbstractHormonal regulation of mouse mammary tumor virus (MMTV) synthesis was studied in the CCL‐51‐SF cell subline derived from the Sykes' mammary tumor cell line CCL‐51 and adapted to grow in semisynthetic in vitro conditions. The virus was quantitated by measuring the supernatant reverse transcriptase activity in exogenous reaction using poly (rA) · oligo (dT) and poly (rC) · oligo (dG) as template/primers. The cells produced a low but significant amount of virus in the absence of any hormones and serum proteins. The synthetic glucocorticoid dexamethasone increased production considerably, up to 100‐fold. Pretreatment of CCL‐51‐SF cells with serum or 5‐bromodeoxyuridine, BrdUrd, partly reduced the stimulation by dexamethasone of MMTV production. Insulin and prolactin alone or in combination had no stimulating effect on spontaneous MMTV synthesis and cell growth. Prolactin, and more efficiently the prolactin‐insulin combination, enhanced the MMTV production stimulated with dexamethasone. Insulin alone remained without effect. The polyamine spermidine, but not spermine, increased the MMTV production over the control by a factor of 2. Polyamines did not influence cell replication at the concentrations used.
Detergent solubilization and partial purification of tumor specific surface and transplantation antigens from SV40‐virus‐transformed mouse cells
Authors: Chang Chungming , Pancake Samuel J. , Luborsky Samuel W. , Mora Peter T. 
Published: February 2007

AbstractA solubilization technique employing 0.5% Triton X‐100 was developed to obtain both SV40 virus (SV40)‐induced tumor‐specific surface antigen(s) (TSSA) from SV40‐transformed mouse cells, as determined by a serum‐mediated microcytolytic assay, and tumor‐specific transplantation antigen(s) (TSTA), as determined by in vivo experiments. High yields (˜50%) of TSSA were obtained in whole‐cell extracts and also after ammonium sulfate fractionation. Additional fractionation of a 30–50% ammonium sulfate fraction by gel exclusion chromatography on Sephadex G‐150 resulted in two pooled fractions which contained TSSA activity. The first eluted close to the void volume, and the second in the 45,000 molecular weight region. The various TSSA active fractions were also active in in vivo TSTA tests. Detergent solubilization provides a suitable technique to recover the SV40‐induced antigens in good yield, and apparently in intact form.
Natural anti‐tumor serum reactivity in balb/c mice. I. Characterization and interference with tumor growth
Authors: Ménard Sylvie , Colnaghi Maria I. , Porta Giuseppe Della 
Published: February 2007

AbstractA natural cytotoxic reactivity directed against syngeneic or allogeneic tumor cells was demonstrated in serum of BALB/c mice by an in vitro cytotoxicity test using rabbit serum as the source of complement. The reactivity, studied on syngeneic fibrosarcoma cells, was found to be minimal in mice less than 10 weeks old and to increase progressively with age. T‐deprivation determined an increase of reactivity in young mice to levels reached spontaneously only by the serum of 40‐week‐old mice. The BALB/c serum also revealed natural anti‐thymus antibodies. Non‐identity between anti‐tumor and anti‐thymus antibodies was demonstrated by direct cytotoxicity and absorption tests. An inoculum of syngeneic fibrosarcoma cells increased the level of anti‐tumor serum reactivity in both normal and T‐deprived young mice. The natural anti‐tumor cytotoxicity revealed in vitro seemed to exert a specific in vivo protection as suggested by the indirect correlation found between the level of the natural anti‐tumor reactivity and the growth of a transplanted fibrosarcoma.