bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytotoxicity of sera from healthy persons and cancer patients
Authors: Arpels Claude , Southam Chester M. 
Published: February 2007

AbstractOne hundred and forty sera from 68 cancer patients and 34 healthy persons were tested for cytotoxicity against human cell lines HEp2, AdenoCx 1 and Amnion B by using 20% test serum as the only serum in the culture medium and incubating for 5–7 days. Evaluation included cell counts, dye exclusion tests, and qualitative grading of cell growth on a basis of 0 to ++++. Final analyses were based entirely on the qualitative grading. Only sera which caused unequivocal toxicity (0 or + growth) were classified as cytotoxic.Cytotoxicity was unrelated to the cell line used for the tests. Toxicity gradually diminished during storage at ‐20° C, but reproducibility of repeated tests of the same serum was good if sera were stored less than 3 months. In studies of multiple serum specimens from the same individual, some persons, both cancer patients and healthy controls, showed inconstant toxicity which was not related to any recognized change in the donor's condition or activities. Toxicity was not related to sex or age. Toxicity was much more frequent in sera from patients with leukemia and lymphoma (74%) than in healthy controls (19%) and somewhat more frequent (39%) in sera from patients with other forms of cancer. Amongst the cancer patients toxicity was somewhat less frequent in sera from patients with the most aggressive cancers, but the difference could easily have occurred by chance. Medications (especially cancer chemotherapeutic agents), various„blood chemistry”︁ determinations, and blood counts had no clear relationships to serum toxicity, but the data did not exclude the possibility that certain medications (e.g. daunomycin) and certain metabolic abnormalities (e.g. uremia) cause sera to be toxic. Patients of blood group A more commonly had cytotoxic serum than did group O patients.The phenomenon of serum cytotoxicity offers no promise as a diagnostic test for cancer because of the frequency of both „false positive”︁ and „false negative”︁ reactions. Neither is it of prognostic value since it was not consistently related to survival or severity of disease. The increased frequency of cytotoxicity in sera from cancer patients as compared to healthy persons is highly significant statistically, but the cause and biological significance of the phenomenon remain an enigma.
Studies on cellular immunity and its serum‐mediated inhibition in moloney‐virus‐induced mouse sarcomas
Authors: Hellström Ingegerd , Hellström Karl Erik 
Published: February 2007

AbstractA colony‐inhibition technique was used to demonstrate lymph‐node cell (LNC) mediated immune reactions against tumor‐specific transplantation antigens of primary, Moloney sarcoma virus induced mouse sarcomas. Lymph‐node cells from mice in which Moloney sarcomas had regressed spontaneously (regressors), as well as LNC from mice carrying progressively growing tumors (progressors), induced by virus inoculation at an age of 14 days or older, reduced the plating efficiency of Moloney sarcoma target cells.Serum from mice with progressively growing Moloney sarcomas, but not from mice with spontaneous mammary carcinomas or methylcholanthrene‐induced sarcomas, abrogated the inhibitory effect of regressor LNC on Moloney sarcoma cells. Additional evidence for the specificity of the serum effect was obtained in experiments showing that the protective effect of progressor sera could be specifically removed by absorption with Moloney sarcoma cells. Regressor sera gave no protection against target cell inhibition by regressor LNC. It is suggested that progressor sera contain antibodies which mediate an efferent form of immunological enhancement.
Cellular immunity and its serum‐mediated inhibition in shope‐virus‐induced rabbit papillomas
Authors: Hellström Ingegerd , Evans Charles A. , Hellström Karl Erik 
Published: February 2007

AbstractA colony‐inhibition technique was used to demonstrate lymph‐node‐cell (LNC) mediated immune reactions against tumor‐specific transplantation antigens of Shope‐virus‐induced papilloma and carcinoma cells. Lymph‐node cells from rabbits in which Shope papillomas had regressed spontaneously, as well as LNC from rabbits with persistent Shope papillomas, reduced the plating efficiency of Shope‐virus‐induced papilloma and carcinoma cells but did not affect normal skin fibroblasts from the same rabbits as the tumor cells.Serum from rabbits with persistent Shope papillomas or Shope carcinomas abrogated the inhibitory effect of regressor LNC on Shope tumor cells, while serum from regressor rabbits had no such effect. It is postulated that sera from “persistor” and carcinoma rabbits contain antibodies which mediate an efferent form of immunological enhancement.
Ribonuclease‐susceptible charged groups at the surface of ehrlich ascites tumour cells
Authors: Weiss L. , Mayhew E. 
Published: February 2007

AbstractThe electrophoretic mobilities of Ehrlich ascites tumour cells are significantly reduced following treatment with bovine pancreatic ribonuclease. This loss of net surface negativity has been intensively investigated, and has been shown to be due to the enzymatic activity of the ribonuclease, as distinct from non‐specific adsorption of this basic protein.The experimental data are consistent with the concept that RNA is a structural component of the cell periphery.
Infectious but non‐leukemogenic friend leukemia virus obtained after prolonged cultivation in vitro
Authors: Yoshikura H. , Hirokawa Y. , Ikawa Y. , Sugano H. 
Published: February 2007

AbstractA non‐leukemogenic strain of Friend leukemia virus (FLV) propagated in vitro interfered with infection by murine sarcoma virus (Moloney) (MSV) and acted as a helper of defective MSV. This suggests that the non‐leukemogenic strain of FLV is infectious. After prolonged propagation in vitro, the leukemogenicity of a highly leukemogenic strain of FLV gradually decreased, while the infectivity assayed by interference with MSV infection remained unchanged.
Prevention of carcinogenesis by murine sarcoma virus (Harvey) following injections of immune sera during the latent period
Authors: Bubeník J. , Turano A. , Fadda G. 
Published: February 2007

AbstractSeveral immune sera were prepared by immunization of mice and rats with murine sarcoma virus (MSV‐Harvey) or with irradiated tissue of MSV‐induced tumours.Repeated injections of these sera into mice and rats which had been inoculated at birth with MSV (Harvey) effectively prevented MSV carcinogenesis. All the immune sera contained antibodies capable of neutralizing MSV. Sera containing the highest titres of virus‐neutralizing antibodies were also the most effective in prevention of MSV carcinogenesis.Passive transfer of some of these immune sera into adult and newborn mice did not influence the growth of MSV‐induced tumour cells transplanted into syngeneic recipients. Other sera either enhanced or inhibited tumour growth. Because of this no correlation could be established between the effect of sera on tumour growth and their capacity to prevent MSV carcinogenesis.
The inhibition by cytosine arabinoside of the replication of murine leukemia and sarcoma viruses in mouse embryo cultures
Authors: Hirschman Shalom Z. , Fischinger Peter J. , O'Connor Timothy E. 
Published: February 2007

AbstractCytosine arabinoside is a potent inhibitor of DNA synthesis in mammalian cells in tissue culture but allows RNA synthesis to proceed. When added to mouse embryo cultures cytosine arabinoside prevented the replication of the Rauscher and Moloney murine leukemia viruses. These viruses were assayed in vitro by the leukemia virus helper assay. After an initial 7‐h exposure of Rauscher‐virus‐infected mouse embryo cells to either 10−5 M or 10−4 M cytosine arabinoside a maximum yield of only 10% of virus compared to control infected cultures was obtained after 48 h of incubation. In a similar experiment with the Moloney leukemia virus only 25–40% of virus was present in cytosine arabinoside‐treated infected cultures at day 7 of incubation when compared to controls. Cytosine arabinoside inhibits the replication of both competent and defective isolates of murine sarcoma virus in mouse embryo cultures. Under similar conditions cytosine arabinoside did not interfere with the growth of vesicular stomatitis virus in mouse embryo cultures.
The formation of variants with a reversion of properties of transformed cells. III. Reversion of the structure of the cell surface membrane
Authors: Inbar Michael , Rabinowitz Zelig , Sachs Leo 
Published: February 2007

AbstractThe cell surface structure of variants from polyoma‐transformed cells grown in animals and then cultured in vitro, which show a reversion of in vitro properties of transformation without losing the ability to synthesize the polyoma‐specific nuclear tumor (T) antigen, has been studied by using the carbohydrate‐binding protein concanavalin A (Con. A) which interacts with sites on the cell surface membrane. Transformed cells are agglutinated by this protein. Normal cells, whose sites for Con. A are mainly in a cryptic form, are agglutinated only after they have been treated with trypsin. It has been shown that some variants showed a partial, and others a complete, loss of agglutinability by Con. A, and that the agglutinability of these variants was restored by treatment with trypsin. Compared to the parental transformed cells, all the variants showed the same decrease in cloning efficiency in fluid medium and soft agar, and in saturation density. The results indicate that the surface structure of transformed cells can completely revert to the structure found in normal cells, as measured by reversion to the cryptic form of sites for Con. A; that the synthesis of T antigen, presumably due to integrated virus DNA, is by itself not sufficient to prevent this reversion; that variants with this reversion in cells grown in vitro can have a high degree of tumorigenicity in animals; and that a threshold for the number of exposed surface sites for Con. A has to be exceeded before the cells express the in vitro properties of transformation.
Studies on plasma membranes. X. A survey of enzyme activities displayed by plasma membranes isolated from mouse liver and three mouse hepatoma strains
Authors: Emmelot P. , Bos C. J. 
Published: February 2007

AbstractPlasma membranes were isolated from CBA‐mouse liver and three transplanted mouse hepatomas having spontaneously arisen in old CBA males.The membranes were assayed for enzymes which had previously been demonstrated in isolated rat‐liver plasma membranes. Marked differences in the specific activities of some enzymes (e.g. 5′‐mononucleotidase) of mouse‐ and rat‐liver membranes were noted.The changes observed in the specific enzyme activities and the stability of certain enzymes of the hepatoma membranes, relative to the corresponding properties of liver membranes, were of three types: (a) those common to all three hepatomas; (b) changes restricted to individual hepatoma strains; and (c) changes developing during the natural history of a given hepatoma strain maintained by transplantation.It is concluded that tumor individuality and progression are expressed at the level of the plasma membrane enzymes. The number of changes in plasma membrane enzymes of a particular hepatoma relative to liver may serve as a measure of deviation of that tumor from the homologous normal resting tissue, but the impact of these membrane changes on tumor‐cell behavior is unknown.
Smoking patterns in Africans and Indians of natal
Authors: Schonland Mary , Bradshaw Evelyn 
Published: February 2007

AbstractA high lung cancer rate for African males and a lower rate for Indian males of Durban, Natal, indicated that a study of smoking patterns in Africans and Indians of this region was required.In Part A, a comparison, in African males, of the smoking habits of 45 lung cancer patients and 90 non‐cancerous patients shows that there is a close association between lung cancer and the amount and duration of smoking in this group.In Part B, a comparison between 236 African male patients and 130 Indian male patients who did not suffer from cancer indicates that Africans start smoking at an earlier age than Indians, and that the use of home‐rolled cigarettes is more frequent among Africans than among Indians. While a comparison of smoking patterns between younger males indicates that the younger Indian is a heavier smoker than the younger African, a comparison between older males shows that the older Indian male is not a heavy smoker, whereas the older African male is. These differences between Africans and Indians might account for the higher lung cancer incidence in Africans at present.The greater consumption of tobacco by younger males of both groups than by older males suggests that the incidence of lung cancer may rise in the future. This prediction is based on the assumption that the smoking patterns emerging from this survey reflect the smoking habits of the general population and that the trend towards heavier smoking in younger males will continue. Brief consideration of other factors, such as exposure to occupational carcinogens, pulmonary scarring and domestic air pollution, appears to indicate that Africans are more at risk than Indians for all factors.
Isolation of membrane‐associated tumour‐specific antigen from an aminoazo‐dye‐induced rat hepatoma
Authors: Baldwin R. W. , Moore M. 
Published: February 2007

AbstractTumour‐specific antigen on the surface of cells of a transplanted rat hepatoma (D23), originally induced by 4‐dimethylaminoazobenzene, was assayed by its capacity to absorb antibody directed specifically against this component and demonstrable by membrane immunofluorescence tests with viable hepatoma cells in suspension. Quantitative assay of antigen in subcellular fractions of tumour, in comparison with that on intact cells, was obtained by this method, the specificity of antibody absorption being confirmed by the lack of effect of intact cells or subcellular fractions of other rat hepatomas and unrelated tumours.Homogenization of hepatoma cells by nitrogen cavitation resulted in the release of membrane fractions retaining hepatoma‐D23‐specific antigen, the recovery being 13 to 17% of that expressed on intact tumour cells. Antigen was equally distributed between large‐particle (sedimented at 10,000 × g) and small‐particle (sedimented at 105,000 × g) fractions, indicating that the method of cell rupture produced antigen‐associated membrane fragments of varying size. No antigenic activity was detectable in soluble cytoplasmic fractions of the tumour. These studies demonstrate that tumour‐specific antigen can be isolated in membrane fragments with the same individual specificity as that demonstrated by immunofluorescence staining of intact hepatoma cells with immune serum or by the induction of tumour immunity.
Some factors affecting membrane immunofluorescence reactivity of burkitt lymphoma tissue culture cell lines
Authors: Yata J. , Klein G. 
Published: February 2007

AbstractMembrane immunofluorescence (MIF) reactivity of Epstein‐Barr virus (EBV) carrying cultured Burkitt's lymphoma (BL) cells with BL sera shows certain fluctuations from time to time, even with standard reference sera and apparently constant tissue culture conditions. In order to determine the culture conditions that are critical for this variation and to establish the optimal situation favoring the production of highly reactive cells, we studied two established BL‐derived cell lines under different conditions of initial cell number, cell density per unit volume or bottom unit area in the culture vessel, depth of the fluid phase, proportion of conditioned medium, etc. Although the two lines behaved somewhat differently, they showed better reactivity when maintained at a high concentration, as long as crowding did not entirely prevent cell multiplication. Under identical conditions of medium supply and depth of the fluid phase, more closely packed cells within a smaller bottom area of the culture vessel exhibited a better MIF reactivity than more dispersed cells. Under different conditions of growth, there was an inverse relationship between the rate of cell multiplication and the percentage of viable MIF‐positive cells. Optimal conditions with steady, high‐level reactivity have been worked out for both lines, but were different with regard to quantitative detail.
Some effects of pH and formaldehyde on the cellular electrokinetic surface
Authors: Weiss L. , Cudney Toni L. 
Published: February 2007

AbstractWhen the electrophoretic mobilities of many cells are measured in solutions having pH values in excess of 9, or after formaldehyde‐fixation, there is an increase in their net surface negativity which is usually attributed to deprotonation of amino‐groups at the cell surface. A detailed investigation of the effects of high environmental pH and formaldehyde treatment on cell electrophoretic mobility suggests that the mobility changes are largely due to the adsorption of released intracellular contents to the cell surface and that, contrary to current belief, information obtained by experiments of this type may not be interpreted to indicate the presence of positively‐charged groups at the electrokinetic surfaces of intact living cells.
Malignant and transforming activity of rous sarcoma virus. I. Malignant effect of rous sarcoma virus
Authors: Obukh I. B. , Kryukova I. N. , Biryulina T. I. , Kuznetsova N. N. 
Published: February 2007

AbstractCultures of cells from embryos of Af, C3H‐Hp/2 and (CBAT6T6 × Af)F1 mice rapidly developed oncogenicity for syngeneic animals after exposure to RSV (Carr‐Zilber strain). The tumours of mice were virogenic and contained the group‐specific antigen of avian sarcoma‐leukosis complex. However, when the infected cells became transformed in morphology, they lost their oncogenicity for syngeneic animals.
Transformation of hamster cells in vivo and in vitro by an adenovirus 4‐SV40 hybrid
Authors: Easton John M. , Rabson Alan S. , Malmgren Richard A. 
Published: February 2007

AbstractA preparation of adenovirus 4, containing infectious SV40 genetic material enclosed within adenovirus coats (Ad. 4‐SV40 hybrid), induced both transformation of newborn hamster kidney cells in vitro and tumors in neonatally inoculated hamsters. Injection of transformed cells into an irradiated weanling hamster also resulted in a tumor. Histologically, all of the tumors were fibrosarcomas similar to those induced in vivo by SV40 alone; no epithelial elements were noted. The three tumors were carried as serial transplants in hamsters; each of the three lines maintained a morphology slightly different from that of the other two. Sera from hamsters carrying the tumors contained antibodies to T antigens induced in cell cultures of African green monkey kidney by Ad. 4 and Ad. 7, but not by Ad. 12. This confirmed work by others, working with Ad. l‐SV40 and Ad. 2‐SV40 hybrid viruses, who found that genetic material from nononcogenic adenoviruses can be introduced into tumors and transformed cells by these hybrids. The cross‐reaction with cells infected with Ad. 7 provides additional evidence for a relationship between Ad. 4 and the B subgroup of oncogenic adenoviruses.
Characteristics of a tumor cell line and virus derived from hamster tumors induced by rauscher leukemia virus‐transformed hamster embryo cells
Authors: Rhim Johng Sik , Huebner R. J. , Ting R. C. , Wivel N. , Vass W. 
Published: February 2007

AbstractA transplantable hamster tumor (RHT‐1) induced by Rauscher leukemia‐virus‐transformed hamster embryo cells was established in tissue culture, and its characteristics were studied. The tumor cell line also contained group‐specific complement‐fixing antigen and continuously released infectious virus. Electron microscope observation showed that this cell line contained C‐type particles. The virus derived from this line served as “helper virus” for a defective Moloney sarcoma virus (MSV) from a non‐infectious hamster tumor (HT‐1), and rescued infectious MSV by direct superinfection of the HT‐1 cells. This infectious MSV virus, which was identified as MSV (RLV) by the focus neutralization test, produced foci readily in both hamster embryo cells and NIH‐METC. Foci produced by this MSV (RLV) pseudotype in hamster embryo cells consisted largely of spindle‐shaped cells which stained vividly with acridine orange. Tumors were produced when cell‐free supernates of MSV (RLV)‐transformed hamster embryo cells, or the cells themselves, were injected into newborn mice. Tumors were also produced when transformed cells were injected into newborn hamsters.
Evidence for effects of heparin on cell surfaces influencing experimental metastases
Authors: Hagmar Björn , Norrby Klas 
Published: February 2007

AbstractThe effect of heparin on tumour cells and on intravenously induced metastases was studied in a syngeneic tumour‐host system, MCG1‐SS in CBA mice. In vitro heparin induced significant changes in the volumes of cells, but did not affect their aggregability or vitality. In vivo heparin did not affect the subcutaneous transplantability of tumour cells. Metastasis formation from intravenously injected cells was differently affected when heparin was given as intravenous pretreatment to animals, than when the same amount was given in the cell suspensions. Thus, pretreatment of animals with heparin affected pulmonary metastases only to a small degree, but gave an increased number of tumour takes in extrapulmonary organs. These changes were ascribed to systemic effects of heparin, above all on blood coagulability.When given in the cell suspensions, heparin did not affect the number of extrapulmonary “takes”, but induced significant changes in pulmonary metastases. The average volume of such metastases became consistently smaller, while their number, if anything, rose. These effects were interpreted as being due to direct actions of heparin on the surfaces of tumour cells, probably related to its polyanion character. It was pointed out that in previous experiments with animals given large heparin doses, a direct cell effect might also prevail. Another polyanion, chondroitin sulphate, caused similar although less pronounced changes than heparin in vitro and in vivo. The polycation protamine had roughly opposite effects.
Modifications du Mëtabolisme Glucidique dans le Foie en Voie de Cancërisation par le Dimëthylaminoazobenzëne III. Recherches au Niveau de la Voie des Pentoses Phosphates
Authors: Jacob A. 
Published: February 2007

AbstractAfin d'expliquer l'hypoglycëmie observëe chez les rats, au cours de la cancërisation du tissu hëpatique par le DAB, nous avons ëtudië la voie des pentoses phosphates. La quantitë de G6P entrant dans cette voie augmente durant le processus de cancërisation, par suite de l'augmentation de l'activitë G6PDH. La baisse d'activitë de la 6‐phosphogluconate dëhydrogënase dëtourne une partie du 6PG de la voie des pentoses phosphates, ce qui pourrait ëtre une des causes de l'hypoglycëmie. Il n'y a pas de modification de l'utilisation du R5P dans le tissu cancëreux.