bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tumorigenesis of mammary gland by 7,12 dimethylbenz(a)anthracene during pregnancy: Relationship with DNA synthesis
Authors: Sinha Dilip K. , Pazik James E. 
Published: February 2007

AbstractThe relationship between mammary cell proliferation during pregnancy and susceptibility to 7,12‐dimethyl‐benz(a)anthracene (DMBA) was examined. DMBA was administered intravenously to Sprague‐Dawley rats on the 5th, 10th or 15th day of pregnancy. [3H]thymidine labelling index (LI) of the mammary cells at the time of treatment with the carcinogen was determined and found to be higher in the pregnant rats than in agematched virgin controls. In spite of the high proliferative index of the mammary cells, significant inhibition of tumorigenesis occurred in the pregnant rats allowed to complete pregnancy and parturition following treatment with DMBA. However, when pregnancy was terminated by cesarian section shortly after treatment with DMBA, there was a significantly higher tumor incidence as compared to the ‘full‐term’ rats. It was observed that the earlier the pregnancy was terminated, the greater was the incidence of mammary tumors. This would indicate that the inhibitory effect of pregnancy is related to changes occurring during the later half of gestation. The differentiation of mammary cells for milk synthesis as pregnancy progresses is postulated to be a major reason for the observed refractoriness of the mammary cells to DMBA at that time.
Lack of induction of murine mammary tumor virus expression in cultured mammary glands treated with chemical carcinogens
Authors: Tonelli Quentin J. , Long Carole A. , Vaidya Akhil B. , Sorof Sam 
Published: February 2007

AbstractChemical carcinogens have previously been found to bring about an epithelial transformation of mouse mammary glands in whole‐organ culture, as evidenced by the escape of lobuloalveoli from the normal hormonal controls of mammary development, and by glandular hyperplasia, dysplasia and metaplasia. In order to assess whether a general induction of endogenous murine mammary tumor virus (MuMTV) genes is associated with the chemical transformation process, we assayed steady‐state levels of MuMTV RNA and protein after treatment of the cultured mammary glands with the carcinogens, 7,12‐dimethylbenz[a]anthracene and N‐2‐fluorenylacetamide. Viral RNA was measured by hybridization with a representative MuMTV‐complementary DNA probe, and viral protein was analyzed by a group‐specific radioimmunoassay for the major MuMTV envelope glycoprotein, gp52. In control glands not treated with carcinogen, there were extremely low levels of MuMTV‐specific RNA in the cultured mammary glands originating from BALB/c mice, and between 10‐ and 50‐fold higher levels in glands from C57BL/6 and C3H mice. Among the untreated glands, only those from C3H mice contained a detectable level of gp52. This order of MuMTV gene expression in the cultured glands of the three strains of mice is consistent with that observed in vivo. Treatment of the cultured mammary glands of these three strains of mice with either of the two chemical carcinogens resulted in all cases in no elevation in the level of either MuMTV RNA or protein. Thus, our studies indicate that the transformation of the cultured mammary glands by the two chemical carcinogens occurs by a process that apparently does not involve a general induction of endogenous MuMTV gene expression.
Helper virus‐dependent RSV rescue from two lines of hamster cells transformed in vivo by XC RSV
Authors: Svoboda J. 
Published: February 2007

AbstractNewborn hamsters were inoculated with chicken sarcoma tissue produced by XC RSV which had been rescued by transfection from XC cells. Tumours with a latency of up to 20 months appeared in all inoculated hamsters. Three tumour cell lines were successfully established for in vitro growth and cloned. The virus was rescued from the PR RSH‐9 cell line by cell fusion with chicken fibroblasts and from the other two lines (PR RSH‐12 and PR RSH‐14) and clones only if chicken fibroblasts used for fusion had been preinfected with a helper virus. The last two cell lines evidently harboured a functional envgene since the synthesis of transforming virus started soon after they were fused with 16Q cells producing defective BH‐RSV(‐) lacking the envelope glycoprotein. Produced viruses acquired subgroup C specificity which is the specificity of XC RSV originally used for transformation of these two cell lines. The nature of provirus alterations in PR RSH‐12 and PR RSH‐14 cells as well as the mechanisms underlying these changes are discussed.
Monoclonal antibodies to epithelium‐specific components of the human milk fat globule membrane: Production and reaction with cells in culture
Authors: Taylor‐Papadimitriou Joyce , Peterson J. A. , Arklie J. , Burchell Joy , Ceriani R. L. , Bodmer W. F. 
Published: February 2007

AbstractThree hybridomas producing monoclonal antibodies (IgG), reacting with components of the human mammary milk fat globule have been isolated. When tested for binding to a wide range of human cell lines and strains, all three antibodies show negative reactions with fibroblasts, lymphoblastoid cells, and a large number of epithelial cell lines of non‐breast origin. Two of the antibodies (1.10.F3 and 3.14.A3) reacted with seven out of eight breast cancer lines tested, and with epithelial cells cultured from human milk. The other antibody (3.15.C3) reacted with only two of the breast cancer cell lines.
Plasma prolactin levels and breast cancer: Relation to parity, weight and height, and age at first birth
Authors: Kwa H. G. , Cleton F. , Bulbrook R. D. , Wang D. Y. , Hayward J. L. 
Published: February 2007

AbstractPlasma prolactin has been measured in over 3,500 women volunteers from a normal population. In premenopausal women there was a significant decrease in prolactin levels with increasing parity. However, this effect was transitory since plasma prolactin concentration rose with increasing time after the birth of the last child. There were no significant differences in prolactin levels with respect to height and weight, although overweight compared to underweight women had approximately 15% more plasma prolactin. If prolactin is a carcinogen, then these results are in keeping with the epidemiological findings that multiparity affords protection and that age at last delivery is a risk factor in the development of breast cancer.
Characteristics of membrane and cytosol forms of the mammary tumor glycoprotein molecule mtgp in human breast carcinoma cell cultures and tumors
Authors: Leung Julia P. , Nelson‐Rees Walter A. , Moore George E. , Cailleau Relda , Edgington Thomas S. 
Published: February 2007

AbstractThe presence, concentration and selected molecular characteristics of the human mammary carcinoma glycoprotein molecule set MTGP, a trace and apparently tumor‐specific molecule, were examined in fifteen cell cultures established from mammary carcinomas, tissue from seven mammary carcinomas and control cultures. Both cytosol and membrane‐associated forms of MTGP were analyzed, and each was phenotyped by reference to isoelectric point and buoyant density. All cells or tissues of mammary carcinoma origin contained membrane MTGP, whereas cytosol MTGP was undetectable in cell cultures from half of the mammary carcinomas. Neither membrane nor cytosol MTGP were detectable in cells other than mammary carcinomas. Cytosol MTGP could be assigned to three groups by reference to presence, isoelectric point and buoyant density. Membrane MTGP also exhibited heterogeneity between different tumors and could be assigned to three groups by isoelectric point and buoyant density. Each form of MTGP was homogeneous for a given single tumor or cell culture and retained its phenotypic features with passage and cloning. Four general types of MTGP are proposed, though there may be additional fine heterogeneity that cannot be further resolved at this time. These data provide an initial characterization of the membrane form of MTGP and an integrated characterization that is consistent with the concept that tumor‐specific antigens may possess both constant regions by reference to antigens recognized by the antisera and variable structure by reference to physicochemical characteristics.
Primary hepatocellular carcinoma in alaskan natives, 1969–1979
Authors: Heyward William L. , Lanier Anne P. , Bender Thomas R. , Hardison H. Huntley , Dohan Peter H. , McMahon Brian J. , Francis Donald P. 
Published: February 2007

AbstractThe records of 20 Alaskan Native patients with primary hepatocellular carcinoma (PHC) diagnosed in the II‐year period 1969–1979 were reviewed. The annual incidence of PHC was found to be high among Alaskan Native males and especially high among Alaskan Eskimo males (7.6 and 11.2 per 100,000, respectively) in comparison to Greenland and Canadian Eskimos and US white males. Familial and geographic clustering of PHC patients was noted in areas known to be hyperendemic for hepatitis B virus (HBV) infection. A bimodal age distribution among PHC patients occurred with peaks at 15–25 years and 40–65 years. A high prevalence of hepatitis B surface antigen (HBsAg) in serum of patients in the younger age group suggests that HBV infection might be a factor associated with the development of PHC in young Eskimos. PHC in Alaskan Natives is apparently not closely associated with alcoholic cirrhosis.
Moloney virus (M‐MuLV) leukemogenesis: Virus spread, antibody production and antigenic expression in neonatally virus‐inoculated young mice
Authors: Åsjö Birgitta , Fenyö Eva Maria , Klein George 
Published: February 2007

Abstract(A × C57BL) and (A × C57L)F1, hybrid mice were inoculated neonatally with M‐MuLV. Virus spread, antigenic expression and antibody production were followed during the preleukemic period. M‐MuLV was first detectable in the spleen and later in the thymus. Virus spread was faster and the level of viremia higher in A × C57L than in A × C57BL mice. Also, A × C57L mice had no or only low titers of virus neutralizing antibodies, whereas A × C57BL mice had high titers. Anti‐MCSA antibodies, reacting with the surface of syngeneic M‐MuLV‐induced lymphoma cells, were present in a minority of the mice, but disappeared ultimately in all mice. The two groups of mice differed with regard to the length of the preleukemic latency period. High virus load and a low level of virus neutralizing and anti‐MCSA antibodies were correlated with an earlier onset of leukemia.
Relationship of carcinogen‐induced sister chromatid exchange and neoplastic cell transformation
Authors: Popescu N. C. , Amsbaugh S. C. , Dipaolo J. A. 
Published: February 2007

AbstractSister chromatid exhanges (SCE) and morphological transformation induced by five chemical carcinogens, N‐acetoxy‐2‐fluorenyl‐acetamide (AcAAF), N‐methyl‐N‐nitro‐N‐nitrosoguanidine (MNNG), methyl methanesulfonate (MMS), benzo[a]‐pyrene (BP), and cis‐platinum(II) diamine dichloride (PT) as well as by X‐irradiation were quantified in parallel experiments with cultures of Syrian hamster embryo cells (HEC). Incubation of HEC with 5‐bromodeoxyuridine (10−5M) for two rounds of replication (24 h) required for SCE visualization neither caused morphological transformation nor altered the transformation frequency induced by carcinogen alone. All chemical carcinogens, but not X‐ir‐radiation, produced a dose‐dependent increase in SCE and transformation frequency, demonstrating the sensitivity of both assays to carcinogens. The ratios of induced SCE relative to transformation frequency, however, varied with the carcinogen. BP, MNNG, and AcAAF were similarly efficient in inducing SCE compared to transformation but were considerably less effective than MMS and PT. X‐irradiation at doses of 200, 300, and 500 R did not cause transformation and induced a low frequency of SCE. On a molar basis, MMS and PT were the most effective in SCE induction relative to transformation, MNNG and AcAAF were less effective, and BP was the least effective carcinogen. The positive linear correlation between chemical carcinogen‐induced SCE and transformation suggests a relationship between the two cellular responses.
The dependence of tumor neutralization on bone‐marrow‐derived cells
Authors: Scuderi Philip , Rosse Cornelius 
Published: February 2007

AbstractRadiosensitive host cells capable of potentiating tumor neutralization by immunocytes in normal recipients are present only in the bone marrow and not in the spleen or thymus. This was shown by selectively eliminating either the bone marrow, spleen or thymus of groups of mice and then subcutaneously injecting these animals with sensitized splenocytes and tumor cells. Bone marrow ablation was accomplished by the administration of the bone‐seeking radioactive isotope 88Sr which did not reduce thymic or splenic cellularity. Sensitized splenocytes completely inhibited the growth of admixed tumor cells in normal, nude, splenectomized, or 88Sr‐treated animals, but the sensitized cells were as ineffective in 89Sr‐treated recipients as in 900‐rad irradiated mice. Bone marrow cells of normal donors admixed with sensitized splenocytes and the sensitizing tumor cells caused a significant inhibition of tumor growth in 900‐rad and 89Sr‐treated mice. Therefore, the radiation‐sensitive host cells that potentiate the tumor‐inhibitory effect of sensitized splenocytes are unique to the marrow and, in the intact animal, apparently emigrate from this organ to interact with sensitized immunocytes at the site of tumor growth.
Induction of epstein‐barr virus by a new tumor promoter, teleocidin, compared to induction by TPA
Authors: Yamamoto Hidehiko , Katsuki Takato , Hinuma Yorio , Hoshino Hiro‐O , Miwa Masanao , Fujiki Hirota , Sugimura Takashi 
Published: February 2007

AbstractThe effect of teleocidin, a new, naturally occurring tumor promoter, on induction of Epstein‐Barr virus (EBV), was compared with that of a known tumor promoter, 12‐O‐tetradecanoyl‐phorbol‐13‐acetate (TPA). Early antigen (EA) and/or capsid antigen (VCA) of EBV was induced in the EBV genome‐carrying cell lines C‐6 and P3HR‐I cells by teleocidin, its effect being maximal at a concentration of 12.5 ng/ml. The production of infectious EBV from P3HR‐I cells was enhanced by teleocidin maximally at a concentration of 0.5 to 2.5 ng/ml. The outgrowth of EBV‐transformed cells from peripheral lymphocytes of seropositive healthy donors was also enhanced by teleocidin at a concentration of 0.02 to 0.5 ng/ml. TPA tested simultaneously in all experiments exhibited the same activities as teleocidin, and was effective at similar concentrations. Teleocidin enhanced both EA and VCA synthesis in P3HR‐I cells additively with n‐butyrate, but not with TPA. This suggests that teleocidin and TPA have a common mechanism of action, although their chemical structures are different.
Establishment of human cytotoxic T‐cell lines specific for epstein‐barr virus‐transformed autologous cells
Authors: Sugamura Kazuo , Tanaka Yuetsu , Hinuma Yorio 
Published: February 2007

AbstractEBV‐specific cytotoxic T cells (Tc)1 induced in vitro have continuously proliferated in vitro for over 9 months. The long‐term maintenance of the Tc growth was dependent on periodic supplementation of both irrediated EBV‐transformed autologous lymphoblastoid cell line (LCL) cells and conditioned medium. The latter was derived from supernatants of human spleen‐cell cultures stimulated with phytohemagglutinin. The cultured Tc maintained significant cytotoxic activity to autologous LCL cells but not to EBV‐unrelated target cells, including K‐562, B‐, T‐, null‐cell lines and mitogenstimulated autologous peripheral blood lymphocytes. Thus, established EBV‐specific Tc lines from five different individuals always exhibited highly significant cytotoxicity against autologous LCL cells but not always against allogeneic LCL cells. Furthermore, restriction of the Tc to the autologous LCL was more pronounced after long‐term culture than it was initially. This suggests that certain clones of Tc which are probably restricted to HLA are selectively established during long‐term cultivation.
Smoking and the development of metastases from malignant melanoma
Authors: Shaw Helen M. , Milton Gerald W. 
Published: February 2007

AbstractInvestigations on 2583 malignant melanoma patients indicated that in both men and women, although there did not appear to be a causal relationship between cigarette smoking and melanoma, smoking did facilitate the spread of metastases. Significantly more ex‐smokers or smokers than life‐long non‐smokers first presented for melanoma treatment with established metastases. Also, in patients with localized disease, metastases appeared within 10 years more often in exsmokers than in life‐long non‐smokers.
In vivo anti‐tumor effects of local adoptive transfer of mouse and human cultured lymphoid cells
Authors: Gorelik E. , Kedar E. , Sredni B. , Herberman R. 
Published: February 2007

AbstractMouse and human lymphoid cells were cultivated in the presence of T‐cell growth factor (TCGF) and evaluated for their in vivo anti‐tumor effect in mice. Cultured spleen cells of normal BALB/c mice or of mice bearing the M109 tumor had a high level of cytotoxic acitivity in vitro against a variety of tumor target cells and had characteristics of natural killer cells. These cultured cells were evaluated for their in vivo cytotoxic activity by admixture with [125l]dUrd‐labelled M109 tumor cells (2 × 105) at a 30:1 ratio and inoculation of the mixture into the footpads of BALB/c mice. The level of radioactivity remaining in the footpad was determined at various periods following inoculation of radiolabelled tumor cells. The presence of cultured cells in the inocula caused a marked decrease in the footpad radioactivity by 24 h. However, the slope of clearance of the radiolabel then became similar to that in the control mice. The cultured cells delayed, but did not prevent, tumor appearance, and did not influence the subsequent rate of growth of the tumors. The transient effects of the cultured cells contrasted with the more prolonged in vivo effects of alloimmune lymphocytes, and this may be due to their short survival period. Ninety‐nine percent of [125l]dUrd‐labelled cultured mouse lymphoid cells were eliminated within 48 h of i.f.p. inoculation. Cultured human lymphoid cells, initiated from the blood of normal donors, also had a high level of cytotoxic activity in vitro and were evaluated for their in vivo effects by intra‐footpad inoculation into nude mice, together with radiolabelled human tumor cell lines, G‐ll or HT‐29. In vivo cytotoxic activity of the human cultured lymphoid cells correlated with their cytotoxic effect in vitro. These results indicate that cultured mouse and human effector cells have appreciable in vivo cytotoxic effects against tumor cell lines. However, the transient duration of these effects may limit their immunotherapeutic potential.
Natural killing and antibody‐dependent cellular cytotoxicity in specific‐pathogen‐free miniature swine and germ‐free piglets. II. Ontogenic development of NK and ADCC
Authors: Huh Nam Doll , Kim Yoon Berm , Koren Hillel S. , Amos D. Bernard 
Published: February 2007

AbstractThe ontogenic development of natural killing (NK) and antibody‐dependent cellular cytotoxicity (ADCC) in germ‐free and specific‐pathogen‐free (SPF) miniature swine were compared. Activities of NK and ADCC were tested by a short‐term (2.5 to 4 h) 51Cr‐labelled human myeloid cell line K562 and TNP‐conjugated human B‐cell line SB as target cells for NK and ADCC, respectively. Animals obtained by aseptic hysterectomy 3–5 days prior to term showed ADCC activities similar to adult levels but lacked NK activity. Hysterectomy‐derived piglets which were colostrum‐deprived and maintained in germ‐free isolators developed NK activity at 3–4 weeks of age. In comparison, naturally‐farrowed, colostrum‐fed piglets maintained in our SPF facility developed NK activity at 2–3 weeks of age. Thereafter, there was no significant difference in the levels of either NK or ADCC between germ‐free and SPF animals. This suggests that microbial flora and environment do not affect the development of effector cells for ADCC but do play some role in the maturation of NK cells during ontogeny. The differences in ontogeny of NK and ADCC further support our previous suggestion that the effector cells for NK and ADCC in swine are distinct subpopulations.
Comparison of various serological and direct methods for the diagnosis of BLV infection in cattle
Authors: Gupta P. , Ferrer J. F. 
Published: February 2007

AbstractThe sensitivities of several serological and direct methods for the detection of bovine leukemia virus (BLV) infection in cattle have been critically compared. Among the serological methods, the radioimmunoassay (RIA) using the BLV glycoprotein (gp) was found to be more sensitive than the RIA using the internal virion antigen (p25) and the immunodiffusion test using the virion gp antigen. The differences in sensitivity between these tests were particularly evident with sera of cattle in early stages of infection. The sensitivities of the syncytia induction assay and the competitive RIA for the direct demonstration of BLV infection in cattle are comparable. Following natural infection, antibodies to the gp antigen in most cattle were detected by the RIA several months before infectious BLV became detectable by the SIA in the blood lymphocytes. It is concluded that the most accurate, sensitive, and rapid method for the detection of BLV infection in cattle is the RIA using the virion gp antigen. The data presented confirm that BLV infection as well as the antibody responses of naturally infected cattle to the BLV p25 and gp antigens are persistent.
Tumour cells in metastatic deposits with altered sensitivity to natural killer cells
Authors: Brooks Colin G. , Flannery Graham R. , Willmott Neville , Austin Eric B. , Kenwrick Susan , Baldwin Robert W. 
Published: February 2007

AbstractIf natural killer (NK) cells play a role in immunosurveillance it might be expected that, during the metastatic process, selection would occur for tumour cells with reduced NK sensitivity. This hypothesis was tested in the rat by measuring the NK sensitivity of cells freshly isolated from metastases of syngeneic transplanted spontaneous mammary carcinomas. Lysis was measured in a 6‐h chromium release assay using normal syngeneic spleen cells as effectors. Our studies led to the following conclusions. (I) Metastases developing at certain tissue sites (draining lymph node and lung, but not pericardium) were frequently composed of tumour cells with markedly reduced sensitivity to NK cells. (2) This resistance could generally be detected only if freshly isolated tumour cell populations were studied; after a few days in culture, resistant metastasis‐derived tumour cells usually regained normal NK sensitivity. (3) Resistance to NK cells was not always due to the loss of NK target structures; it could also result from an innate resistance to the NK lytic mechanism. (4) The tissue distribution of NK‐resistant metastases suggested that if NK cells exerted an immunoselective pressure they did so at the tissue site rather than in the primary tumour or in the bloodstream.
Mapping of the Fv‐4 mouse gene controlling resistance to murine leukemia viruses
Authors: Ikeda Hidetoshi , Sato Hidetoshi , Odaka Takeshi 
Published: February 2007

AbstractFv‐4, a gene controlling susceptibility to ecotropic murine leukemia viruses, was linked to both Pre‐1 (prealbumin) and Igh‐1 (immunoglobulin heavy‐chain constant region) loci on chromosome 12 in mice. The gene order was Fv‐4‐Pre‐1‐Igh‐1, and the estimated frequency of recombination between Fv‐4 and Pre‐1 was about 20%.