bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neutralizing EBV‐specific IgA in throat washings of nasopharyngeal carcinoma (NPC) patients
Authors: Desgranges C. , De‐Thé G. , Ho J. H. C. , Ellouz R. 
Published: February 2007

AbstractThroat washings from 26 nasopharyngeal carcinoma (NPC) patients from Hong Kong and Tunisia were studied for the presence of transforming EBV. Only six (23%) were found positive which led to the hypothesis of a neutralizing factor in such salivas. The search for EBV‐specific antibodies showed that NPC saliva contained neutralizing VCA and EA IgA (54 and 27% respectively) and VCA and EA IgG (73 and 54% respectively). Both transforming and non‐transforming throat washings contained virus particles as visualized by electron microscopy, but in non‐transforming salivas (containing IgA and IgG) the particles were found to be clumped. Comparative study of throat washings from patients with Burkitt's lymphoma (BL), infectious mononucleosis (IM), immunodeficiencies, other cancers, and healthy subjects showed that IgA were restricted to NPC cases.
Detection of SV40 T antigen with labelled antibodies: Radioimmunoassay and autoradiography
Authors: Flügel R. M. , Crefeld T. , Munk K. 
Published: February 2007

AbstractSV40 T antigen, partially purified from SV80, a human cell line, has been used to develop a sensitive solid phase radioimmunoassay. In this assay SV40 T antigen was immobilized on microtiter plates, reacted with hamster anti‐SV40 T antibody and subsequently with 14C‐labelled anti‐hamster IgG. The test detected approximately 20 ng of partially purified SV40 T antigen and is rapid and more convenient than the complement fixing reaction. An immunoautoradiographic method which permits the determination of the cellular localization of SV40 T antigen and which is possibly more sensitive than the indirect immunofluorescence method is also described.
An analysis of the factors allowing promotion (rather than inhibition) of tumour growth by corynebacterium parvum
Authors: Bomford R. 
Published: February 2007

AbstractThe following factors were found to determine whether C. parvum (CP) treatment promoted rather than inhibited the growth of methylcholanthrene‐induced fibrosarcoma cells injected into CBA mice. (1) The dose of tumour cells. Promotion occurred only with low doses, around the TD50. (2) The route of injection of CP. Greater promotion was caused by intravenous (IV) than by subcutaneous (SC) administration. Addition of irradiated tumour cells to SC CP resulted in tumour inhibition. (3) The dose of CP. Promotion increased with increasing dose of either SC or IV CP. (4) The time of CP injection relative to tumour challenge. Promotion only occurred when CP was given before tumour cells, except when using IV CP and very few tumour cells. With increasing doses of tumour cells, first post‐treatment with IV CP and then pre‐treatment became inhibitory. The effect of CP on established immunity to tumour cells was also studied. Mice were immunized by tumour amputation. The resistance to tumour challenge thus generated could be abrogated by CP given before challenge, most effectively by a high dose IV. The data are interpreted according to the following hypothesis. (1) CP suppresses the expression of cell‐mediated immunity to tumour antigens. (2) This is caused by trapping of anti‐tumour effector cells at the site of CP deposition. (3) Promotion can only occur when CP is given before effector cells have reached the tumour site.
Primary tumor immunity in nude mice
Authors: Prehn Liisa M. , Outzen Henry C. 
Published: February 2007

AbstractTumor implants grew better in radiated or in newborn nu/nu mice than in adult nu/nu controls when, and only when, the tumors were demonstrably immunogenic in normal mice. This result suggests primary immunity. No evidence of immunological memory was found by immunization‐challenge type experiments in the nude mice.
Carcinogenicity of DDT (dichlorodiphenyl trichloroethane) in pure inbred Swiss mice
Authors: Kashyap S. K. , Nigam S. K. , Karnik A. B. , Gupta R. C. , Chatterjee S. K. 
Published: February 2007

AbstractInbred Swiss mice were treated with technical DDT (1) orally with the diet or by intubation; (2) subcutaneously and (3) by skin painting. The total duration of the experiment was 80 weeks. There was no difference in body growth and mortality between the experimental and control groups. Toxic manifestations of DDT were observed in treated mice in the form of tremor, convulsions and corneal opacity usually after 40 weeks. Oral and subcutaneous DDT treatment resulted in a significant increase in the incidence of tumours mainly of lymphoid tissues, lung and liver. The highest tumour incidence was recorded in the group of mice receiving DDT by subcutaneous injections. Males and females were equally susceptible. No evidence of carcinogenicity was observed in the painted group.
Transformation of normal hamster cells by benzo(a)pyrene diol‐epoxide
Authors: Mager Rivka , Huberman Eliezer , Yang Shen K. , Gelboin Harry V. , Sachs Leo 
Published: February 2007

AbstractThe frequency of cell transformation was determined after treatment of normal hamster embryo cells with benzo(a)pyrene (BP) and six of its metabolites. These metabolites included the trans 4,5‐, 7,8‐ and 9,10‐dihydrodiols; the 4,5‐epoxide; and two stereoisomers of the non‐K‐region diol epoxides r‐7, t‐8‐dihydroxy t‐9, 10‐oxy‐7,8,9,10‐tetrahydro‐benzo(a)pyrene (diol‐epoxide I) and r‐7, t‐8, dihydroxy c‐9, 10‐oxy‐7,8,9,10‐tetrahydrobenzo(a) pyrene (diol‐epoxide II). The trans 7,8‐dihydrodiol was more active than the other two dihydrodiols tested and was also more active than the parent hydrocarbon BP. Of the three epoxides tested, the diol‐epoxide I was more active than the 4,5‐epoxide and diol‐epoxide II. The results suggest that diol‐epoxide I is a major cell‐transforming metabolite of BP.
Biological characterization of a tumour‐growth‐promoting factor from ascitic fluid of tumour‐bearing mice
Authors: Henriksen Ole , Law Lloyd W. 
Published: February 2007

AbstractTumour‐growth‐promoting activity has been observed in ascitic fluids of mice with progressively growing SV40‐ and chemically induced tumours. Administration of ascitic fluid to animals together with a normally non‐tumorigenic dose of SV40‐transformed tissue culture cells (TU‐5) will cause these cells to grow progressively and eventually kill the animals. Also, the mKSA‐specific, immunologically non‐responsive state (the eclipse phase) of mice bearing large mKSA tumours can be maintained by administration of ascitic fluid or serum from tumour‐bearing animals after the tumours have been surgically removed. Normally, complete immunity to a secondary tumour cell challenge is re‐established approximately 10 days after removal of the primary tumour, but daily injections of ascitic fluid or serum will maintain eclipse so that a secondary challenge of tumour cells will grow progressively. The active component apparently acts non‐specifically, since ascitic fluid from an unrelated tumour also is able to maintain the mKSA‐specific eclipse phase. The ascitic fluid has no apparent immunosuppressive activity in vivo.
Binding of soluble form of fibroblast surface protein, fibronectin, to collagen
Authors: Engvall Eva , Ruoslahti Erkki 
Published: February 2007

AbstractFibronectin, a plasma protein immunologically identical with a major surface protein of normal fibroblasts, was found to bind to collagen and gelatin. A solid phase enzyme immunoassay was used for the binding tests. Collagen, gelatin or various control proteins were adsorbed to a plastic surface. Binding of fibronectin was detected using purified fibronectin antibodies conjugated to alkaline phosphatase. Circulating fibronectin and fibronectin obtained from fibroblast cultures both showed specific binding to collagen and gelatin. Preparative affinity chromatography of plasma on gelatin coupled to Sepharose gave electrophoretically and immunologically pure fibronectin in high yields. Malignantly transformed fibroblasts lack surface fibronectin. Our findings suggest the possibility that this results in a lack of anchorage to the surrounding intercellular matrix, which could contribute to the malignant growth behavior.
Epstein‐Barr herpesvirus infection: Inhibition by immunologically induced mediators with interferon‐like properties
Authors: Lai P. K. , Alpers P. , MacKay‐Scollay E. M. 
Published: February 2007

AbstractWhen sensitized leukocytes were re‐exposed to EBV antigen or to tuberculin‐purified protein derivatives, they produced lymphokines, including the migration inhibition factor, which inhibited the migration of guinea‐pig peritoneal exudate cells, and other lymphokines with the characteristics of interferon, which inhibited EBV‐induced transformation and EBV superinfection of target cells. Unsensitized leucocytes from sero‐negative adults and from neonates did not produce lymphokines when challenged with the antigens. This indicates that cell‐mediated immunity and its associated soluble mediators may be involved in the control of EBV infection and that the interferon release assay is a useful in vitro correlate for the study of cellular immunity to EBV.
Nucleic acid content and cell cycle distribution of five human bladder cell lines analysed by flow cytofluorometry
Authors: Traganos F. , Darzynkiewicz Z. , Sharpless T. , Melamed M. R. 
Published: February 2007

AbstractFive human bladder cell lines, four derived from tumor tissue and the fifth originating from presumed benign transitional epithelium, were examined by flow cytofluorometry to estimate the DNA and RNA content per cell during exponential and stationary phases of growth. A new staining technique was employed using acridine orange to differentially stain DNA and RNA in unfixed cells made permeable to the dye and other reagents by treatment with detergent at low pH. Stemline chromosome numbers for each cell line correlated well with relative DNA content of the G1 population as measured by this technique. In addition, the simultaneous measurements of DNA and RNA per cell yielded cell cycle distributions for each cell line. The ratio of stainable RNA/DNA was lower for all cell lines derived from bladder tumors as compared to the presumed normal cell line, indicating high nuclear/cytoplasmic ratios for the former.
Synthesis of type‐C virus particles from murine cultured cells induced by iododeoxyuridine. VI. Biosynthesis of reverse transcriptase
Authors: Reitz M. S. , Wu A. M. , Gallo R. C. 
Published: February 2007

AbstractTreatment with 5‐iodo‐2'‐deoxyuridine (IdUrd) of BALB/3T3 cells non‐productively transformed with Kirsten murine sarcoma virus (K‐BALB) results in the induction of extracellular type‐C virus production with a concomitant appearance of intracellular reverse transcriptase. Production of BALB virus‐2 (v‐2) and its Kirsten sarcoma virus pseudo‐type, occurring 2‐3 days after IdUrd treatment, is inhibited and stimulated by interferon and dexamethasone, respectively, By contrast, and as previously reported, neither compound affects synthesis of N‐tropic virus (BALB virus‐1) which is produced later (5‐7 days) after IdUrd treatment. The stimulatory and inhibitory activities of these compounds are partially antagonistic since: (1) the simultaneous presence of both dexamethasone and interferon results in a virus production level between those observed with either compound alone; and (2) increasing the dexamethasone concentration at a fixed interferon concentration increases virus production. However, the effects of these two compounds on the appearance of an intracellular viral protein (reverse transcriptase) after IdUrd treatment were unexpected. The post‐induction appearance of intracellular reverse transcriptase is inhibited by interferon but is not affected by dexamethasone. This suggests that dexamethasone stimulates a step after protein synthesis, and that interferon inhibits an earlier step (translational or pre‐translational) or that it enhances degradation of viral proteins. When interferon and dexamethasone are both present, no inhibition of the appearance of reverse transcriptase is observed. Thus, dexamethasone has a second effect on virus production, namely to prevent the inhibition by interferon of the appearance of intracellular reverse transcriptase. Since dexamethasone completely overcomes the inhibitory effect of interferon on intracellular reverse transcriptase levels, but only partially reverses the inhibition by interferon of virus production, interferon (in the presence of dexamethasone) must also inhibit a post‐translational step in virus production. This step may or may not be the same as the late dexamethasone‐sensitive step. Thus, both dexamethasone and interferon appear to have both translational (or pre‐translational) and post‐translational effects on the production of xenotropic (v‐2) mouse type‐C virus. This suggests that BALB/c mouse cells restrict the production of xenotropic endogenous virus at two distinct sites.
Separation of the moloney leukemia virus‐determined cell surface antigen (MCSA) from known virion proteins associated with the cell membrane
Authors: Siegert Wolfgang , Fenyö Eva Maria , Klein George 
Published: February 2007

AbstractCell membranes of Moloney lymphoma cells (YAC, of strain A origin) were solubilized by NP40. The antigenicity of the solubilized protein fraction was assayed by inhibition of the corresponding cytotoxic reaction against YAC target cells. The Moloney leukemia virus (MLV)‐determined cell surface antigen (MCSA) was detected with mouse antisera, produced by the repeated inoculation of heavily irradiated YAC cells into syngeneic mice. Virion proteins gp71, p30, p15, p12 and p10 were identified with goat or rabbit antisera against purified Rauscher and Friend leukemia virus proteins. MCSA was found to bind to Con‐A—Sepharose and was eluted by mannoside together with H‐2a and gp71. In contrast, p30, p12, p10 and part of p15 and p15(E), were not retained on the column and could be separated from MCSA. Passage of the glycoprotein fraction through Sephadex G‐200 led to the separation of MCSA activity from gp71 and H‐2a. MCSA eluted between the immunoglobulin (IgG) and the bovine serum albumin (BSA) size markers. MCSA could be also separated from the known viral proteins and from H‐2 by velocity centrifugation in sucrose gradients. It sedimented with approximately 6.6 S ahead of gp71 (4.4 S) and H‐2 (3.2 S). It is suggested that MCSA may be a glycoprotein with an approximate molecular weight of 110,000 and distinct from the known viral proteins gp71, p30, p15, p15(E), p12, p10 and from H‐2.
Tumor necrosis and cell detachment
Authors: Weiss Leonard 
Published: February 2007

AbstractCell detachment from and around Walker 256 tumors grown in rats is quantitated by a standardized in vitro shaking procedure. The volume of cells detached from cancers of similar size is virtually the same in tumors growing in the liver, the spleen, in intramuscular and in subcutaneous sites. In cystic tumors, greater volumes are detached from the innermost regions of the walls adjacent to necrotic material than from the outermost parts. More liver perenchymal cells are shaken free of liver adjacent to a tumor interface than from regions 0.5 and 1.0 cm distant from it. Detachment of tumor and liver cells is also enhanced by prior incubation of tissue samples with necrotic extracts. It is suggested that the necrotic regions of tumors, and products derived from them, facilitate the detachment of tumor cells and cells composing the normal tissues surrounding them, thereby potentially promoting metastasis and invasion.
Natural cytotoxicity to human leukemia mediated by mouse non‐t cells
Authors: Haller Otto , Kiessling Rolf , Örn Anders , Kärre Klas , Nilsson Kenneth , Wigzell Hans 
Published: February 2007

AbstractNatural killer (NK) cells cytotoxic for certain syngeneic or allogeneic tumor cells have been described in various species, including mouse, rat and man, as a new type of effector cell. In this paper, we show that mouse NK cells also function in a xenogeneic system. Established human hematopoietic cell lines were used as targets for normal mouse spleen effector cells in a short‐term 51Cr release assay. Nine malignant lymphoma, two myeloma and four leukemia lines as well as six lympho‐blastoid cell lines of presumed non‐neoplastic origin were tested. Specific and reliable killing was obtained with the T leukemias MOLT‐4, JM, CCRF‐H‐SB‐2 and the myeloid leukemia K 562. Most other lines were sensitive to some degree but their susceptibility and the specificity of the reactions were of doubtful significance. The heterologous cytotoxic reactivity was shown to be caused by the same kind of murine effector cells that mediate NK activity against certain mouse lymphomas by the following criteria: (1) the differences in killing capacity found between spleen cell preparations from genetically “high” or “low” NK‐reactive inbred mouse strains did apply in this heterologous system; (2) cytotoxicity was related in a typical manner to the age of the effector cell donor; (3) spleen cells from T‐deficient nude mice were highly cytotoxic; (4) removal of T cells, B cells and phagocytic cells using standard fractionation procedures did not abrogate the lytic ability of the remaining spleen cell population. Specificity of lysis was assessed using unlabelled cells as competing targets together with labelled target cells. When competitor cells were identical to the target cells, good competition was achieved. Mouse or human cell lines insensitive to lysis by mouse NK cells had no competitive capacity for target cells of either species. Using NK sensitive lines, competition between mouse and human cells was found to be unidirectional with the most sensitive tumors being the best inhibitors. Thus, unlabelled mouse T lymphoma YAC‐1 cells were efficient competitors for lysis of human T leukemia lines. Conversely, susceptible human cells used as competitors did not significantly inhibit killing of YAC‐1 targets. The implications of these findings are discussed.
Establishment of simian sarcoma virus, type 1 (SSV‐1)‐transformed non‐producer marmoset cell lines
Authors: Bergholz Carolyn M. , Wolfe Lauren G. , Deinhardt Friedrich 
Published: February 2007

AbstractSimian sarcoma virus, type 1 (SSV‐1)‐transformed non‐producer cell lines were established by infection of normal marmoset fibroblast cells (HF) with limiting dilutions of SSV‐1. Four focus‐derived cell lines were identified as non‐producers by assay of culture fluids for focus‐forming activity and by the mixed culture cytopathogenicity test with XC cells. Further studies failed to detect production of type‐C virus by 3H‐uridine labelling, reverse transcriptase assay or electron microscopy. The non‐producer cell lines, designated HF/SSV‐NPI, IV, V, and VI, appeared morphologically transformed and cloned in soft agar with the same efficiency as HF/SSV‐1 virus‐producing transformed cells. Expression of either cytoplasmic or cell surface virus‐related antingens was not detected by immunofluorescence or serum cytotoxicity tests. The presence of sarcoma genome in the transformed non‐producer cell lines was demonstrated by rescue of focus‐forming activity following superinfection with non‐transforming helper virus or by cocultivation with helper‐virus‐producing cell lines. The SSV‐1‐transformed non‐producer primate cells provide a useful tool for future studies.
The effect of azathioprine on host cell infiltration and growth of a murine fibrosarcoma
Authors: Evans R. 
Published: February 2007

AbstractAzathioprine (AZ) was injected into C57 Black mice before or after IM implantation of the syngeneic fibrosarcoma FS6, and observations were made on tumour growth and on the cellular composition of the fibrosarcomas. When multiple injections were given to the tumour‐bearing host the tumours regressed. The percentage of tumour‐associated macrophages remained essentially stable as regression occurred whereas the percentage of θ‐antigen‐positive cells increased. In the case of single IP injections of AZ, changes in the cellular composition of tumours were seen only when AZ was given 1‐72 h before implantation but not when it was given after implantation. Compared with controls there was a 2‐ to 3‐week delay in the appearance of large numbers of tumour‐associated macrophages. The percentage of θ‐antigen‐positive cells within the tumours mass was elevated 7 days post AZ treatment but the level declined to control values between days 10 and 13. The significance of the results is discussed in relation to the dependency of the macrophage content of this tumour upon the development of an immune response towards the tumour.
Inhibition of the growth of lymphoid tumours in syngeneic athymic (nude) mice
Authors: Warner Noel L. , Woodruff Michael F. A. , Burton Robert C. 
Published: February 2007

AbstractA comparison of the growth of a number of BALB/c tumours in BALB/c, BALB/c.nu/+ (heterozygous nude) and BALB/c.nu (homozygous) nude mice has shown that a majority of BALB/c lymphoid tumours grow at a significantly reduced rate in BALB/c.nu mice. The three non‐lymphoid BALB/c tumours (carcinomas and sarcomas) tested and a minority of lymphoid tumours, however, grew as well, or better, in the BALB/c.nu mice. Furthermore a correlation, without exception to date, has emerged from a comparison between the susceptibility of a tumour cell line to in vitro lysis by spleen cells from syngeneic nude mice and its growth in vivo in syngeneic nude mice. Only those lymphoid tumour cell lines lysed in vitro show the reduced growth rate in syngeneic nude as compared to syngeneic normal mice. Tumour cell lines, both lymphoid and non‐lymphoid, which are resistant to in vitro lysis do not show the reduced in vivo growth rate in syngeneic nude mice. Both the in vivo and in vitro effect can be partially abolished by irradiating the nude mice prior to use, suggesting that a radiation‐sensitive non‐T‐cell surveillance of lymphoid tumours is operating in nude mice. While the identity of the antigens is still unknown, the specificity of the phenomena suggest that C‐type RNA oncogenic viral determined antigens are involved.
Establishment of a human medulloblastoma cell line
Authors: McAllister R. M. , Isaacs H. , Rongey R. , Peer M. , Au W. , Soukup S. W. , Gardner M. B. 
Published: February 2007

AbstractA cell line consisting of polygonal and fusiform cells was derived from a cerebellar medulloblastoma. Cells grew to high population density in liquid medium and formed colonies in agar medium. No neural or glial elements could be demonstrated in the cultured cells by electron microscopy nor were virus particles detected. The cells formed tumors in nude mice and in antithymocytic serum (ATS)‐treated hamsters. The tumors had a microscopic appearance similar to that of the medulloblastoma from which the cell line was derived. The cell line and lines derived from the transplant tumors in two hosts had four common “marker” chromosomes as well as non‐specific cytogenetic changes.