bluuebunny/crossref_metadata_2025_split huggingface dataset:
A quantitative comparison of the mutagenicity of carcinogenic polycyclic hydrocarbon derivatives in cultured mammalian cells
Authors: Newbold R. F. , Brookes P. , Harvey R. G. 
Published: February 2007

AbstractThe mutagenicity of a series of reactive polycyclic hydrocarbon derivatives has been studied using Chinese hamster (V79) cells in culture and, as a mutational marker, resistance to the purine analogue 8‐azaguanine. The compounds were compared by relating mutation frequency to the dose applied (mutagenic effectiveness) to induced cytotoxicity (mutagenic efficiency) and to the extent of reaction of the hydrocarbon with DNA (absolute mutagenic efficiency). In each case anti‐benzo(a)pyrene (BP)—7,8 dihydrodiol‐9,10 oxide, the suspected ultimate carcinogenic form of benzo(a)pyrene, was by far the most potent of the compounds tested. Furthermore, the mutagenicity of the syn‐ and anti‐BP‐diolepoxide isomers correlated positively with their documented carcinogenic potency. Differences in mutagenic effectiveness are ascribed to predicted differences in the ability of each derivative to form a carbonium ion. Variations in mutagenic efficiency and absolute mutagenic efficiency were more difficult to explain. The latter findings are discussed in relation to the types of hydrocarbon‐DNA product obtained with each compound and also to the possibility of a variable cellular response to more subtle differences in the chemistry of the hydrocarbon‐DNA interaction.
Importance of a collagen substratum for stimulation of capillary endothelial cell proliferation by tumour angiogenesis factor
Authors: Schor Ana M. , Schor Seth L. , Kumar Shant 
Published: February 2007

AbstractTumour extracts were obtained from rat Walker 256 carcinoma and examined for the presence of tumour angiogenesis factor (TAF) in vivo before being used in tissue culture experiments. Capillary endothelial cells derived from cow brain white matter were used to study the effects of TAF‐containing tumour extracts on cell proliferation in vitro. The cells were grown on two types of substrata: (1) plastic tissue culture dishes and (2) hydrated gels made of rat tail tendon type I collagen. Human platelets or platelet‐released factors were introduced into the system because of the many inter‐relationships known to exist between platelets, collagen and endothelial cells. If trypsin was used during the preparation of TAT, the resulting batches stimulated endothelial cell proliferation only when the cells were growing on a collagen substratum and either platelets or platelet‐released factors were present in the growth medium. If incubation with trypsin was omitted from the TAF extraction procedure, the resulting batches stimulated cell growth both on plastic and on collagen. A synergistic interaction also occurred between these TAF‐containing tumour extracts and plateletreleased factors. This effect was always more marked when the cells were growing on collagen than when on plastic. These data suggest that the nature of the substratum affects the response of the endothelial cells to TAF and to platelet‐released factors.
Reversion of the transformed phenotype to the parental phenotype by subcultivation of X‐ray‐transformed C3H/10T1/2 cells at low cell density
Authors: Brouty‐Boyé Danièle , Gresser Ion , Baldwin Claire 
Published: February 2007

AbstractTransformed cells induced by X‐irradiation of a stable contact‐inhibited line of C3H mouse embryo cells (10T½) display an altered morphology (fibroblastic), a decreased sensitivity to contact inhibition, a high cell saturation density, a decreased sensitivity to interferon and a capacity to form colonies in agar and malignant tumors in mice. Under certain experimental conditions, serial passage of transformed cells (from cloned lines) at low cell density (i.e., 400 cells per 25 cm2 flask) was accompanied by a reversion from the transformed phenotype to a phenotype characteristic of the parental untransformed 10T½ cells: epithelioid morphology, low cell saturation density, increased sensitivity to interferon and failure to form colonies in agarose or tumors in mice. The revertent phenotype was stable as long as these cells were passed at low cell density. Passage at high cell density, however, resulted in a back reversion to the transformed phenotype. When transformed cells were seeded at a much lower cell density, so that only a few colonies appeared per Petri dish, reversion to the parental phenotype occurred at the first passage and appeared stable. Back reversion was no longer observed even when these cells were passed at high cell density. The experimental results suggested that reversion of the transformed to the parental phenotype was not due to a selection of a pre‐existing population of cells with the parental phenotype but rather to a change in the phenotype of the entire cell population.
The value of a sensitive assay of carcino‐placental alkaline phosphatase (CPAP) in the follow‐up of gynecological cancers
Authors: Haije W. G. , Meerwaldt J. H. , Talerman A. , Kuipers Tj. , Baggerman L. , Teeuw A. H. , Van Pompe W. B. Der , van Driel Jolie 
Published: February 2007

AbstractUsing a sensitive enzyme immunoassay, carcinoplacental alkaline phosphatase (CPAP) was determined in sera of 1266 patients with gynecological cancers. All these patients were referred after initial surgical treatment elsewhere. There were 95 patients with evidence of disease at the time of the study and 1171 without evidence of disease. Of the 95 patients with active disease, 47 were treated for ovarian carcinoma, 36 for carcinoma of the cervix and 12 for endometrial carcinoma. Raised levels of CPAP were seen in 40% of patients with ovarian carcinoma, in 22% with carcinoma of the cervix and in 41% in the small group with endometrial carcinoma. In patients without evidence of disease, raised levels of CPAP were seen in 12% of patients with carcinoma of the cervix, in 6% of endometrial carcinoma and only in 2% of patients with carcinoma of the ovary. Therefore it was considered that in the latter group CPAP studies would prove of some value. In the group of patients with carcinoma of the ovary and evidence of disease, raised levels of CPAP were seen almost exclusively in patients with epithelial tumors. It is considered that CPAP may be of value as a tumor marker in this group of patients. When compared with CEA, CPAP tends to give fewer false positives and correlates better with the presence of disease.
Demonstration of chicken fetal antigen (CFA) on normal splenic lymphocytes, Marek's disease lymphoblastoid cell lines and other neoplasms
Authors: Murthy K. K. , Dietert R. R. , Calnek B. W. 
Published: February 2007

AbstractChicken fetal antigen (CFA) was detected on normal splenic lymphocytes and a direct relationship was observed between the percentage of CFA‐positive cells and the age of the donor. The fetal antigen was also detected on lymphoblastoid tumor cells and cell lines induced by known avian oncogenic viruses (Marek's disease virus and avian leukosis virus), and on spontaneously occurring adenocarcinoma cells. The fetal antigen appears to be distinct from Marek's disease tumor‐associated surface antigen.
Levels of mammary tumor virus proteins (MTVp27 AND MTVgp52) in the milk of low and high mammary cancer mouse strains of japanese origin compared with european and American strains
Authors: Imai Shunsuke , Hilgers Jo 
Published: February 2007

AbstractA competition radioimmunoassay for purified MTV proteins, MTVp27gag and MTVgp52env, was applied to measure the amounts of these proteins in the milk of various mice of Japanese origin. The results were compared to those from European and American strains of high and low mammary cancer incidence. The sensitivity of detection for the assay was less than 1 ng viral protein per mg milk protein. The SL/NiA strain was positive for MTVp27 in the milk (10–100 ng/mg). Foster‐nursing of this strain on BALB/c mice did not lead to the disappearance of MTVp27 antigen expression, indicating that MTV in this strain is genetically transmitted. This strain was negative for MTVgp52. Various high mammary cancer strains had large amounts of MTV, invariably transmitted in milk, e.g. (1) FM/JmsA, (2) C57BL/6MsMtA, a strain selected for high mammary cancer incidence in Japan and maintained at the Aichi Cancer Center, (3) DD/Tbr. Levels of MTVp27 and MTVgp52 in the milk of these strains were comparable to those of the C3H/HeA, A/BrA and RIII/SeA. They were generally somewhat lower than in the BALB/cHeA strain foster‐nursed on high mammary cancer strain mice, such as A/BrA, RIII/SeA and FM/JmsA. Weight ratios of MTVp27 to MTVgp52 were usually 1:1 with the exception of the BALB/c foster A strain whose levels of MTVgp52 were comparatively high. BALB/cHeA strain milk itself showed some positivity for both MTV proteins at the borderline of detection (around 0.1 ng/mg protein). Mice of the C3H/HeA strain, foster‐nursed on C57BL/LiA mice, have much lower levels of MTVp27 (10–40 ng/mg) and MTVgp52 (8–50 ng/mg) than all the high mammary cancer strains. (C57BL × C3Hf)F1 hybrid mice had even less MTVp27 and gp52 in their milk than the C3Hf strain mice, permitting genetic analysis of the gene(s) for this suppression by the C57BL genotype.
Transplacental mutagenesis of products formed in the stomach of golden hamsters given sodium nitrite and morpholine
Authors: Inui Naomichi , Nishi Yoshisuke , Taketomi Masako , Mori Makiko , Yamamoto Miyako , Yamada Takashi , Tanimura Akio 
Published: February 2007

AbstractHamster embryos were exposed in utero to the action of sodium nitrite (NaNO2) and morpholine (Mo) administered simultaneously by stomach tube to the mothers on the 11th or 12th day of pregnancy. Embryo cells were examined for chromosomal aberrations, micronuclear formation, morphological or malignant transformation and drug resistance mutations. For detection of induced mutations, the embryo cells were cultured in normal medium for 72 h and then transferred to medium containing 10 or 20 μg/ml of 8‐azaguanine (8AG) or 1 mM ouabain (Oua). The number of 8AG‐, Oua‐resistant colonies was markedly increased after administration of NaNO2 and Mo. The embryonic fibroblasts also showed a markedly increased frequency of micronucleation and a slight increase in chromosome aberrations. This treatment also caused morphological or malignant transformation of fetal cells. After cultivation in vitro, cells from some transformed colonies produced tumors when inoculated into the cheek pouch of young golden hamsters. Orally administered N‐nitroso‐morpholine (N‐Mo), as a positive control, had the same transplacental biological actions on embryonic fibroblasts. However, transplacentally Mo alone was ineffective. A single administration of 500 mg/kg NaNO2 had only slight biological effects. N‐Mo was produced in the stomachs of animals treated simultaneously with NaNO2 and Mo. A small amount of a nitrosamine, N‐nitrosodimethylamine (DMN), was detected in the stomach after a single dose of NaNO2.
Alpha‐fetoprotein and γ‐glutamyltranspeptidase in mice. Effect of raf gene
Authors: Jalanko Hannu 
Published: February 2007

AbstractThe regulation of the high physiological level of serum alpha‐fetoprotein (AFP) in BALB/c/J mice was studied. Serum AFP concentration in 7‐ to 12‐week‐old BALB/c/J mice varied from 460 ng/ml up to 2,790 ng/ml and in other strains tested from 10 ng/ml to 400 ng/ml. In contrast to the difference in serum AFP level, activity of the fetal enzyme γ‐glutamyltranspeptidase (GGT) in the liver of BALB/c/J mice was similar to that found in other mice. In all newborn mice, the initially high GGT activity decreased almost 100‐fold during the first 10 days. The serum AFP concentration stayed relatively stable during this period. AFP decreased to the adult level between the 10th and 30th days. Partial hepatectomy and administration of carbon tetrachloride increased the serum AFP level in all mice. The elevation of AFP was 10 times higher in BALB/c/J mice than in mice with low basal AFP level. A slightly elevated GGT activity in the liver was observed in only 10 out of 40 mice after carbon tetrachloride treatment, but none of the mice after partial hepatectomy showed an elevation. These results suggest that the gene (“Raf” gene) controlling the reduced decrease of serum AFP level in young BALB/c/J mice enhances the “turning on” of production of AFP in the regenerating liver. This gene does not, however, control the expression of the other carcinofetal liver marker, GGT.
Epstein‐barr virus‐specific antibody‐dependent cellular cytotoxicity in patients with Burkitt's lymphoma
Authors: Pearson Gary R. , Qualtiere Louis F. , Klein George , Norin Torsten , Bal Inderjit Singh 
Published: February 2007

AbstractCoded sera from 54 patients with African Burkitt's lymphoma (BL) were titrated for antibodies against an Epstein‐Barr virus (EBV)‐induced membrane antigen in the antibody‐dependent cellular cytotoxicity (ADCC) assay. The titers were then correlated with the progression of lymphoma growth following chemotherapy. In 74% of the patients with high ADCC titers (>3,840), lymphomas showed partial or complete regression following therapy. In the medium‐titered group (240–3,840), 36% of the lymphomas showed some response to therapy, while only 29% of the lymphomas in the low group (<240) responded to treatment. These preliminary results indicated that, as previously reported for patients with nasopharyngeal carcinoma, ADCC titers may be of prognostic value in patients with this EBV‐associated disease. In an attempt to determine the identity of the ADCC antigen, some of these sera were examined for antibody to the four major MA components so far identified in the membrane of EBV‐infected Raji cells. Sera with high ADCC titers in general contained antibody to the four major MA components, while low‐titered sera usually contained antibody to three or less of these proteins. There were exceptions to this pattern, however, indicating that the ADCC antigen might differ from the four EBV‐induced membrane components so far identified.
Growth requirements of human cervical epithelial cells in culture
Authors: Stanley Margaret A. , Parkinson E. Kenneth 
Published: February 2007

AbstractDiploid cells derived from the portio surface of the cervix uteri of adult women can be grown in culture, from single cells. Ultrastructurally the colonies of growing cells show the features of stratified squamous epithelium and exhibit some of the differentiated characteristics of this epithelium in vivo. The successful serial cultivation of cervical epithelial cells, HCE, depends upon the presence of a non‐dividing fibroblast feeder layer which provides both attachment and growth factors for epithelial cells. Lethally irradiated Wi‐38, cervical fibroblasts or mouse fibroblast lines are all effective in promoting HCE colony formation and growth. Hydrocortisone and epidermal growth factor increase HCE colony size in the presence of a feeder cell layer. Culture lifetime was studied in five strains and ranged from 20–38 population doublings, with cells from older patients exhibiting a shorter culture life‐time.
Aryl hydrocarbon hydroxylase inducibility in lung cancer patients undergoing radiotherapy
Authors: Prasad Naresh , Prasad Rupi , Harrell James E. , Thornby John , Liem John H. , Hudgins Philip T. , Guinn Gene A. 
Published: February 2007

AbstractAryl hydrocarbon hydroxylase (AHH) inducibility was studied in cultured lymphocytes from 21 healthy control subjects and from 15 lung cancer patients selected for radiation therapy. AHH inducibility of the patients was measured prior to, during and at the end of radiation therapy. Four of 15 patients had high AHH inducibility. The remaining 11 patients had values comparable to the healthy controls. Cellular DNA and protein measurements of cultured lymphocytes were the same for patients and healthy controls. There was no significant difference in the percentage of lymphoblast formation and percentage of cell survival between the two groups. Radiation therapy reduces the number of lymphocytes in vivo and the amount of lymphoblast formation in vitro. AHH inducibility is significantly lowered by radiation in the patients who had very high inducibility at pre‐treatment level. DNA and protein contents of cultured lymphocytes did not change during radiation therapy.
Hepatitis b virus antigens in human primary hepatocellular carcinoma tissues
Authors: Goudeau A. , Maupas Ph. , Coursaget P. , Drucker J. , Chiron J. P. , Denis F. , Mar I. Diop 
Published: February 2007

AbstractThe presence of hepatitis B virus (HBV) antigens was examined in specimens of liver tissue obtained at necropsy from black Senegalese patients suffering from primary hepatocellular carcinoma (PHC). The results were correlated with markers of hepatitis B infection in serum. Hepatitis B surface antigen (HBsAg) and core antigen (HBcAg) were sought for in 15 liver extracts. HBsAg was found in the liver in 10 of 12 cases with HBsAg‐positive serum. HBcAg was detected in three livers. The HBsAg was detected in seven of eight livers by immunofluorescence and orcein staining. HBsAG‐positive cells were mainly located in the peri‐tumoral cirrhotic tissue, although positive hepatocytes were also found in tumour nodules in liver from one of the patients. HBcAg was found in five of seven cases by immunofluorescence in hepatocytes of the cirrhotic areas. HBcAg fluorescence was primarily nuclear but, in some lobules, a patchy cytoplasmic fluorescence was observed. This suggests a cytoplasmnucleus pathway in the synthesis of the HBV core antigen. Electron microscopy was performed on two HBsAg‐ and HBcAg‐positive cases. Fibrillar and crystalline cytoplasmic inclusions were observed in tumour cells. In the same cells, 20–25 nm virus‐like particles were present in swollen cisternae of the endoplasmic reticulum.
Serum, pituitary and urine concentrations of prolactin and growth hormone in eight strains of mice with varying incidence of mammary tumors
Authors: Sinha Y. N. , Vlahakis G. , Vanderlaan W. P. 
Published: February 2007

AbstractEight inbred strains of mice with varying incidences of spontaneous mammary tumor were compared in regard to prolactin and growth hormone concentrations in sera, pituitary glands and urine. Serum prolactin was compared under basal conditions as well as after stimulation with perphenazine. Both hormones were measured with specific, homologous radioimmunoassays. Although some strains having a high incidence of mammary tumors had high levels of prolactin in sera, urine and pituitary glands, neither basal nor perphenazine‐induced serum concentrations showed a consistent pattern across mouse strains that correlated with the incidence of mammary tumors. Growth hormone levels in sera, pituitary glands and urine also had no characteristic pattern that applied to all strains studied. The ratio of prolactin depleted from the pituitary gland to prolactin detected in serum after perphenazine injection, which reflected the metabolic clearance rate of prolactin, was highest in two strains with a high incidence of mammary tumors and relatively lower in low‐tumor strains. These results suggest that if prolactin plays a part in mammary tumor development in mice, its mechanism varies with strains: while hyperprolactinemia may be the means in some strains, a peculiarity in the metabolism of the hormone may be more important in others.
Rauscher leukemia as a model for studies of marrow transplantation therapy: Results using syngeneic, allogeneic and hybrid donors
Authors: Okunewick James P. , Meredith Ruby F. , Brozovich Barbara J. , Seeman Paul R. , Schieb Ann L. 
Published: February 2007

AbstractSJL/J mice with leukemia induced in their own cells by Rauscher leukemia virus were treated by marrow transplantation therapy. The results obtained using syngeneic, hybrid and two different allogeneic donors were compared. All types of donor tissue produced some degree of protection; the lowest was yielded by SJL/J cells and the highest by C57BL/10J. The incidence of leukemia recurrence after therapy varied with the donor strain used. The highest and earliest recurrence was seen with SJL/J donors. The use of leukemia‐resistant SJB10F1 hybrids resulted in protracted remissions followed by late relapse, which was possibly related to reemergence of host leukemogenic clones not previously eliminated by the pretransplant marrow ablation treatment. A distinctly different pattern of late deaths was seen with the use of allogeneic donors, suggesting a possible graft‐vs‐leukemia effect. Graft‐vs‐host (GvH) response was not evident following transplantation of either the hybrid or syngeneic marrow, as determined from studies using normal SJL/J mice as recipients. GvH disease was found using both types of allogeneic donors, C57BL/10J and 129/J. However, although both allogeneic donors were of the same histocompatibility type, H‐2b, they differed in the level of fatal GvH response induced when used as donors. This suggests the possibility of an influence of « minor » histocompatibility factors affecting GvH response incidence and animal survival. The similarities between the model and the results of treatment of human leukemia by marrow transplantation therapy are discussed, and the possible future use of the model to study means of achieving lower leukemia recurrence through better marrow ablation, and to study the question of whether there is a graft‐vs‐leukemia effect related to GvH response, is proposed.
Contribution of macrophages to interactions between tumor cells and other tissues assessed in an in vitro system
Authors: Maslow D. E. , Weiss L. 
Published: February 2007

AbstractThe modification of the tissues surrounding solid tumors is usually attributed exclusively to interactions between the normal tissues and the cancer cells in the tumor, in spite of the fact that tumors contain many different types of non‐cancer cells including macrophages. As an experimental model for some facets of the cellular interactions between tumor and normal tissues, we have assessed the individual contributions of macrophages and cancer cells to the differential inhibition of neural retina (NR) cell aggregation by co‐culturing NR cells with small numbers of macrophages or cancer cells alone, as well as with both natural (ascites tumors) and artificial mixtures. Cells from human colonic adeno‐carcinoma inhibited NR aggregation to a greater extent than normal colon mucosa. Aggregation of NR cells was inhibited by macrophages from mice and rats, and to a greater extent by cancer cell suspensions of mouse Ehrlich and rat Walker 256 lines from spinner culture or in the ascites form. Combinations of macrophages and cancer cells indicated that their inhibitory effects were neither additive nor synergistic. Cell‐free media from macrophages and cancer cell cultures were equally effective inhibitors of aggregation. The results suggest that the interaction between a malignant tumor and the surrounding normal tissue can be modified by cancer cells, tumor macrophages and their products.
In vivo induction of endogenous retroviruses in BALB/c mouse hepatocytes by successive treatments with carbon tetrachloride and bromodeoxyuridine
Authors: Ayukawa Hannah M. , Saltzburg Donna , Mukherjee Barid B. 
Published: February 2007

AbstractThe effects of bromodeoxyuridine (BrdUrd) incorporation into hepatocytes of carbon tetrachloride (CCl4)‐induced regenerating liver of BALB/c mice on the induction of endogenous retroviruses was examined. From the nucleic acid hybridization studies, the maximum levels of hybridization were obtained for both N‐ and X‐tropic BALB/c endogenous retrovirus specific [3H]‐cDNAs with liver RNA from animals receiving BrdUrd at 40 and 44 h post‐CCl4 treatment, and killed on the fourth day following BrdUrd injection. Media from NIH‐3T3 (Swiss mouse) and mink cell cultures, infected with liver homogenates from animals treated as above, gave significant levels of reverse transcriptase activity. The observations made in the present study show that BrdUrd incorporation into cell DNA can cause induction of both N‐ and X‐tropic endogenous retroviruses in BALB/c mouse hepatocytes in vivo, and such induction is probably a transient event.