bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibitory effect of rifampicin on rauscher‐virusinduced murine leukaemia
Authors: Gielkens A. L. J. , Burghouts J. T H. M. , Bloemendal H. 
Published: February 2007

AbstractRifampicin has a marked inhibitory effect on Rauscher‐virus‐induced leukaemia. Up to 90% inhibition of splenomegaly can be achieved when the drug is administered immediately after infection. It is suggested that these results may have implications for a rational leukaemia therapy.
Sv40‐induced transformation of cells of the lizard Gekko gecko
Authors: Clark H. Fred , Jensen Fred , Defendi Vittorio 
Published: February 2007

AbstractAttempts to infect four cell lines of reptilian origin, GL1 (Gekko gecko), IgH‐2 (Iguana iguana) and VH2 and VSW (both Vipera russelli), with SV40 led to successful infection of the lizard cell line GL1 only. SV40 infection, indicated by acquisition of persisting T antigen in 100% of the cell population, was obtained in cells inoculated and maintained at 23, 30 or 35°C. (The optimal temperature for GL1 cell growth is 30°C). In early passages, infected GL1 cells exhibited a more orderly growth pattern and a more uniform cell morphology than did control cells. However, at about the 50th passage level after infection, a more exuberant growth pattern developed, characterized by cell saturation densities exceeding those of control cell cultures approximately threefold. Infectious virus in low titer was recovered from cells and media of infected cell lines tested during the first 21 passages post infection. At subsequent passage levels, virus could be rescued from cells maintained at each of the three different incubation temperatures by co‐cultivation with AGMK cells, but not directly from the cultures. The presence of SV40 tumor‐specific transplantation antigen was demonstrated by experiments in which hamsters inoculated with infected GL1 cells received marked protection against SV40 tumor induction. Further evidence of the altered state of the SV40‐infected cells was provided by demonstration of increased resistance to inhibition of cell growth by dextran sulfate, and an enhanced ability of the cells to multiply at supraoptimal temperatures. The evidence indicates that cells of a poikilothermic vertebrate have been transformed in vitro by the mammalian papovavirus SV40. This is the first demonstration of which we are aware of viral transformation of poikilothermic cells in vitro.
Chromosomal mechanism for the induction of reversion in transformed cells
Authors: Bloch‐Shtacher Navah , Rabinowitz Zelig , Sachs Leo 
Published: February 2007

AbstractThe changes in chromosome constitution that occur during induction of reversion in transformed cells have been studied. The culture of transformed cells at low cell density without a feeder layer, which induces reversion, also induced a change in chromosome number from diploid to aneuploid. The percentage of revertants formed under these conditions was related to the percentage of aneuploid cells. Most of the aneuploid cells had a subtetraploid chromosome number. The results indicate that the formation of aneuploids is due to the formation from binucleate cells of polyploid cells which later lose chromosomes, and suggest that conditions that stabilize the reverted state produce the right type of stable aneuploid cells required for reversion.
The sugar content and the ph of the smoke of cigarette, cigar and pipe tobaccos in relation to lung cancer
Authors: Elson L. A. , Betts T. E. , Passey R. D. 
Published: February 2007

AbstractThe risk of lung cancer is greater in cigarette smokers than in cigar or pipe smokers. In Great Britain, which has a very high lung‐cancer death rate, cigarette tobacco (flue‐cured) has a high sugar content (up to 20%) while cigar tobacco (aircured) has a low sugar content (0.5—2%). Determinations of the sugar content of the tobacco and the pH of the smoke of cigarettes from more than 30 countries, and of a number of cigar and pipe tobaccos, have been carried out. The main differences found between the characteristics of cigarette and cigar and pipe tobaccos are:

The high sugar content of the popular brands of cigarettes now smoked in many countries, which results in the production of a smoke of acid pH, becoming progressively more acid during the course of smoking, particularly towards the butt‐end of the cigarette when the tar content of the smoke is at its highest;
The low sugar content of cigar tobacco and of the air‐dried tobacco used in the cigarettes of certain countries, which gives a smoke of less acid pH becoming progressively more alkaline during the course of smoking;
The conditions of smoking in a pipe whereby the smoke from all types of tobacco, with both high and low sugar content, is less acid than that of most cigarettes, and becomes progressively more alkaline during the course of smoking.
Since the satisfaction derived from smoking is mainly due to the pharmacological effects of nicotine, it is suggested that the lower lung cancer incidence in cigar and pipe smokers may be related to the fact that nicotine is more readily absorbed in the form of the free base, at alkaline pH, than in the form of a stable salt, at acid pH. To obtain the same degree of “nicotine satisfaction” as in smoking a pipe or cigar, the smoker of cigarettes giving an acid smoke would tend to smoke more, and to encourage more prolonged and extensive contact of the smoke with the mouth and bronchus, and to take the smoke into his lungs, which would thus suffer greater exposure to the “carcinogenic” effects of the smoke than would be the case with cigar or pipe smokers.In preliminary attempts to devise a “safer” cigarette, the addition of substances which give rise to an alkaline vapour at the usual temperature of combustion of cigarettes has been shown to reverse the character of the smoke of high sugar (fluecured) tobacco cigarettes so that it then resembles that of cigars and pipes in becoming progressively more alkaline during the course of smoking.
H‐2 antigens on murine leukemia cells and viruses
Authors: Dorfman N. A. , Stepina V. N. , Ievleva E. S. 
Published: February 2007

AbstractElectron microscopic analysis of the distribution of H‐2 (b, d, k) antigens on the cell surface and viruses of Rauscher, Friend, Graffi, Mazurenko, Gross and SZ leukemia was carried out using the hybrid antibody test.H‐2 antigens occupied different areas on the surface of the cells, but their average content per 100 randomly selected cells ranged from 13‐24% in different leukemias. The amount of mature viral particles with H‐2 antigens on their surface did not correspond to the average content of these antigens on leukemia cells and amounted to 7‐15%. H‐2 antigens never covered the entire surface of viral particles and the ferritin label, which made it possible to spot them, was not more than 5‐7 molecules. The same was true of viral buds, the majority of which, even on membrane sites with H‐2 antigens, were devoid of these antigens. Possible reasons for the absence of H‐2 antigens on mature and budding viruses are discussed.
Presence of carcinoembryonic antigen in children's colonic mucosa
Authors: Burtin P. , Sabine M. C. , Chavanel G. 
Published: February 2007

AbstractThe colonic mucosa of 48 young children, nine of them being over one year, and two being seven years old, was studied for the presence of carcinoembryonic antigen (CEA). In all the cases, immunofluorescence with specific anti CEA antiserum was positive. Phytic extracts of three pools of juvenile colonic mucosae contained an antigen giving an identity reaction with reference CEA. CEA is thus a normal antigen in children's colonic mucosa.
The specificity of surface membrane immunofluorescence in human malignant melanoma
Authors: Lewis M. G. , Phillips T. M. 
Published: February 2007

AbstractA study of membrane immunofluorescence on human malignant melanoma cells confirms previous preliminary reports indicating lack of significant cross‐reactivity with other melanoma sera, similar to that described in chemical carcinogen induced tumours. The importance of careful and critical appraisal of this technique is emphasized, and is supported by several other test systems, including cytotoxicity, demonstrating lack of cross‐reactivity. Multiple cross‐reactions with EB3 virus‐infected Burkitt lymphoma cells and glandular fever sera were clearly seen using the same methods of immunofluorescence and interpretation.
The kinetics of the killing of mouse tumour cells in vivo by immune responses
Authors: Porteous D. D. , Munro T. R. 
Published: February 2007

AbstractImmune responses against the C3H mouse ascites tumour BP8 were studied in vivo by measuring the proportion of an inoculum that was killed in allogeneic C57BL animals. Killing was assayed by labelling the cells with 125IUdR; the 125I liberated from dead cells was excreted, and the proportion of label (and thus the proportion of cells) remaining was measured by whole‐body counting. Cell loss from the primary immune response began about a week after intraperitoneal injection of 107 cells, and was accelerated by addition of 107‐108 heavily irradiated cells to the inoculum. By contrast, it began immediately in immunized mice. Labelled cells irradiated with 10,000 R of X‐rays did not begin to lose 125I until 2 days after irradiation, and so could be used to investigate the immune status of an animal without fear of killing it.
Compared action of a polyoma‐virus‐specific inhibitor on the formation of polyoma capsid antigen and of polyoma tumor antigen
Authors: Meyer Georges , Cramer Robert , Yoshikura Hiroshi 
Published: February 2007

AbstractA protein factor which can be extracted from polyoma‐virus‐transformed BHK 21 cells is shown not to inhibit a virus‐coded early function (tumour antigen formation), whereas it inhibits the formation of the virus capsid antigen.
Genetic properties of substituted derivatives of N‐methyl‐4‐aminoazobenzene in relation to azo‐dye carcinogenesis
Authors: Fahmy O. G. , Fahmy Myrtle J. 
Published: February 2007

AbstractA comparative genetic study was undertaken with structurally related N‐methyl‐4‐aminoazobenzenes of varied chemical reactivities and carcinogenicities, including the parent N, N‐dimethyl azo dye (butter yellow) and model compounds of its suspected metabolites. The mutagenic activity of each compound was examined with respect to the specific effects on the heterochromatic bobbed (bb) and Minute (M) loci, relative to general mutability as indicated by the overall response of the X‐chromosome (recessive lethals and visibles) in the same treated genome.The intrinsically non‐reactive compounds, such as the parent dye and its 3′‐methyl derivative, were inactive with respect to the general X‐chromosome mutations (mainly euchromatic genes) and the large heterochromatic M deletions, but were decisively active on the r‐RNA sites (yielding bb's), particularly in mature sperm. The N‐substituted reactive derivatives (amino‐oxy esters and chloroethylamines) were effective to various degrees for all mutational classes, but the reactivation of the ring methyl groups–as with the 3′‐chloromethyl compound–proved to be mutagenically ineffective.Differential mutagenic effects were discernible among the tested azo dyes, with respect both to the affected genes and to the response of the germ cell stages. However, a close similarity occurred between the mutational spectra of the parent azo dye and its N‐benzoyloxy ester, both exerting maximal activity on the bb loci in mature sperm. This is in line with the biochemical evidence that metabolic activation of azo dyes probably proceeds via the formation of amino‐oxy esters.The mutagenic activity and/or selectivity on the bb loci among the tested azo dyes appeared to be correlated with their carcinogenic potential. Specificity for these genes occurred with the hepatocarcinogenic parent dye and its 3′‐methyl derivative, and a high level of selectivity for these sites was also manifested by the N‐benzoyloxy ester which could be regarded as a precursor of the N‐hydroxy intermediate metabolite. The chloroethylamino derivatives produced a level of bb selectivity compatible with their possible in vivo conversion to alkylating carcinogens.The genetic properties of the azo dyes were similar to those of other aromatic amines with comparable oncological activities and were in harmony with the concept that molecular deletions within the r‐RNA loci might be significant in cancer initiation.
Variations in sarcoma and leukemia virus activity in somatic cell hybrids
Authors: Long Cedric , Kelloff Gary , Gilden Raymond V. 
Published: February 2007

AbstractSomatic cell hybrids have been produced in hypoxanthine‐aminopterin‐thymidine (HAT) selective medium by fusion of mouse cells deficient in hypoxanthine‐guanine phosphoribosyl transferase (HGPRT), shedding Rauscher leukemia virus and a hamster cell deficient in thymidine kinase (TK) carrying the defective murine sarcoma virus (MSV) genome. Clones were isolated that produced sarcoma and leukemia virus at substantially equivalent titers, a 100‐fold excess of sarcoma virus, or just leukemia virus. Eight clones were analyzed by isoelectric fractionation and all found to possess HGPRT and adenosine kinase (AK) of hamster origin. Six of these clones also produced AK characteristic of the mouse parent. The production of excess sarcoma virus by some clones and the lack of sarcoma virus expression in cells possessing hamster genetic material are discussed in terms of integration of sarcoma virus in host‐cell chromosomes.
Australia antigen in Singapore Chinese patients with hepatocellular carcinoma and comparison groups: Influence of technique sensitivity on differential frequencies
Authors: Simons M. J. , Yap E. H. , Yu M. , Shanmugaratnam K. 
Published: February 2007

AbstractIn a previous study using electro‐osmodiffusion, the frequency of Australia antigen (Au) in Singapore Chinese patients with hepatocellular carcinoma (2.6%) was no higher than that in comparison groups. Three possible explanations for the apparent discrepancy between this result and the differentially higher Au frequencies reported by others have occurred to us. The first relates to differences in the sensitivities of the techniques employed for Au detection. A second possibility is that the age distribution of Singapore patients with hepatocellular carcinoma (HCC) may differ from that of patients studied elsewhere. Thirdly, differences in Au frequencies may reflect real biological differences between HCC patients in various countries. In this series, using the more sensitive technique of immune adherence haemagglutination, the frequency of Au in HCC patients (35.3%) was more than four times higher than in any comparison group. These findings indicate that Chinese patients in Singapore have lower Au titres than appear to be present in African patients. The previous failure to detect a higher Au frequency in Singapore HCC patients relative to comparison groups can be explained by the difference in sensitivities of the techniques employed. Whether factors such as ethnic type contribute to geographic differences in the Au titres of HCC patients remains to be investigated.
Feline malignant lymphoma: Environmental factors and the occurrence of this viral cancer in cats
Authors: Schneider Robert 
Published: February 2007

AbstractEnvironmental data collected on 221 feline malignant lymphoma cases and age‐, sex‐ and breed‐matched controls were analyzed to find evidence which could prove or disprove a hypothesis of horizontal transmission of feline leukemia virus (FeLV) between cats. The variables studied were divided into three groups: (1) association with other cats; (2) neutering and reproductive experience; and (3) diet, including predatory activities. The analyzed data did not support horizontal transmission of infectious FeLV from cat to cat and the consequential development of malignant lymphoma. Significant differences could not be found for association of case animals with other cats, either within or outside of the household. Secondly, there was no evidence of excess mature non‐neutered cats, particularly males, in the case group. The courtship habits and territorial fights of entire males would dictate that excess of such animals should be present in the case group if horizontal transmission of infectious FeLV occurred. No evidence was found to support the hypothesis that diet, particularly predatory activities, may in some way affect risk. Various hypotheses concerning the pathogenesis of this disease in cats are discussed.
Membrane antigens of human colonic carcinoma and non‐tumoral colonic mucosa: Results obtained with a new isolation method
Authors: Rosai Juan , Tillack Thomas W. , Marchesi Vincent T. 
Published: February 2007

AbstractA new technique is described for the extraction and purification of the carcinoembryonic antigen (CEA) from human tumors.This method involves the use of lithium diiodosalicylate for dissociation of the antigen‐membrane complex. The method differs from earlier procedures in that extraction conditions do not rely on an acid precipitation step and that the yield of CEA appears to be approximately 10‐fold greater.A glycoprotein immunologically similar to CEA was isolated from non‐tumoral human adult colonic mucosa, suggesting that the difference between tumoral and non‐tumoral tissues in this system may be quantitative rather than absolute.
Inheritance of susceptibility to friend mouse leukemia virus. VIII. Effect of a single genetic locus on the pathogenesis of the leukemia
Authors: Odaka Takeshi , Sugano Haruo , Takizawa Kiyoshi 
Published: February 2007

AbstractThe effect of the Fv locus on the pathogenesis of Friend virus‐induced leukemia was studied with two pairs of mouse strains which are congenic except for the locus. The rapid spleen enlargement or spleen focus formation which is characteristic of Friend virus infection occurred in the mice with Fvs/Fvs genotype, DDD and C57BL/ 6‐Fvs. These early responses were not seen in the mice with Fvr/Fvr genotype, DDD‐Fvr and C57BL/6. When the infected Fvr/Fvr mice were observed for 150 days, all of the DDD‐Fvr mice, but none of the C57BL/6, developed splenomegaly. Histological studies of the DDD‐Fvr mice revealed erythroblastic, lymphatic or granulocytic leukemia, or myeloproliferative disorder with a prominent megakaryocyte proliferation. This observation indicates that Friend leukemia virus is able to induce various types of leukemias in mice and the early characteristic responses are completely abrogated in the mice with Fvr/Fvr genotype. Involvement of genetic factor (s) other than the Fv locus in the late‐occurring leukemias was suggested.
Some observations on the epidemiology of cancer of the breast in women of Western India
Authors: Paymaster J. C. , Gangadharan P. 
Published: February 2007

AbstractThe incidence rate for cancer of the breast is comparatively low in India. Cancer of the cervix is more common than cancer of the breast amongst Indian women. Wide variations in the frequency of cancer of the breast have been observed amongst the religious communities of Western India. Compared to other communities, Sindhis (Hindus from Sind) and Parsis (Zoroastrians) have a higher frequency rate for cancer of the breast. It was felt that the prevalence of certain suspected factors may be partly responsible for such variations. Case control studies demonstrated that the role of certain “high risk factors”, especially those related to marriage and pregnancy, could be different in different age groups, and an intensive search for more factors and their significance in different populations and age groups is necessary. The factor or factors which can be used effectively for a public health programme for the prevention of this disease are yet to be demonstrated.
Inhibitors of the bone‐marrow colony formation in sera of patients with leukemia
Authors: Granström M. , Wahren B. , Gahrton G. , Killander D. , Foley G. E. 
Published: February 2007

AbstractAn increased variation of the bone‐marrow colony stimulating factor (CSF) was found in the sera of patients with acute leukemia as compared to normal sera. In sequential samples from the same patient, there was no apparent correlation between changes in the degree of colony stimulating activity and changes in the clinical and hematologic status. CSF levels as measured in untreated sera seemed to depend upon a variation in serum inhibitor levels. After chloroform treatment, sera from patients with acute lymphoid or myeloid leukemias had higher mean CSF activity than similarly treated normal sera, though the variation was considerable in both groups. The increase was most evident in sera which initially exhibited a normal or low degree of colony‐stimulating activity. In order to evaluate CSF in normal persons and in various diseases, it appears important to remove inhibitory substances efficiently, for instance by chloroform treatment.
Cell‐mediated destruction of rous sarcomas in Japanese quails
Authors: Hayami Masanori , Hellström Ingegerd , Hellström Karl Erik , Yamanouchi Kazuya 
Published: February 2007

AbstractA microcytotoxicity test was used to search for cell‐mediated destruction of sarcomas, induced in Japanese quails by the Schmidt‐Ruppin strain of the Rous sarcoma virus (SR‐RSV).Spleen cells from quails whose sarcomas had regressed (regressors) were cytotoxic to cultivated Rous sarcoma cells as were, to a lesser extent, regressor thymus cells, while no cytotoxic effect was seen with bursa cells. Autochthonous and allogeneic lymphoid cells from regressors were equally cytotoxic. No cytotoxic effect was seen, on the other hand, with lymphoid cells from quails with growing Rous sarcomas (progressors).Surgical bursectomy on the day of hatching, which depressed the formation of antibody production to sheep red‐blood cells, led to a higher cytotoxic effect of regressor spleen cells than was seen with cells from non‐bursectomized quails. Spleen cells from thymectomized birds which showed delayed skin graft rejection and had progressively growing rumors were not cytotoxic.Admixture of progressor spleen cells decreased the cytotoxic activity of normal regressor spleen cells unless the regressors had been bursectomized.
Further studies on mouse sarcoma virus (moloney) replication in human cells. Partial host range shift of progeny virus
Authors: Bernard C. , Chuat J. C. , Laprevotte I. , Boiron M. 
Published: February 2007

AbstractSeveral human cell lines were examined for their susceptibility to infection by mouse sarcoma virus, strain Moloney (M‐MSV). Successful transformation was achieved only with concentrated virus from rat cell line 78 Al. The lag time and the extent of cellular alteration were found to be related to the employed multiplicity of infection (total transformation within 4 days at a multiplicity of 0.1). All the experiments performed showed the tropism of the progeny virus (HU‐MSV) to shift from a double murine and human tropism to exclusive human tropism as far as the transforming function is concerned. On the contrary, nontransforming replication in mouse cells was continuously obtained. In vivo studies yielded parallel results: only the leukemogenic potential of HU‐MSV for mice was found to persist. The mechanism of this dissociated host‐range shift of transforming and non‐transforming virions is discussed.