bluuebunny/crossref_metadata_2025 huggingface dataset:
Purification of antibodies to membrane antigens of hamster cells transformed by sv40 and binding of the radioiodinated, purified antibodies to intact cells
Authors: Kedar Eli , Aaronov Aaron , Goldblum Nathan , Sulitzeanu Dov
Published: February 2007

Antisera to membrane antigens of SV40‐transformed hamster kidney cells were prepared by injecting a membrane fraction of HK7 cells into rabbits. Purified antibodies were prepared by adsorption of the IgG fraction of the antisera onto, and by elation from, living or glutaraldehyde (GA) fixed HK7 cells. Purification from GA‐treated cells yielded highly satisfactory purified antibody preparations, the reactivity of which could be demonstrated in fluorescent antibody tests. These preparations were radioiodinated with 125I to a specific activity of the order of 10μc/μg and their activity was assayed by ability to bind to living HK7 cells. The labelled antibodies maintained their binding ability practically unchanged for at least 6 months. They could be further purified by an additional adsorption‐elution cycle, using living cells. The doubly purified, radioiodinated antibodies, had a high affinity for HK7 cell membranes: 43% of the radioactivity became bound when 0.3 ng eluate was reacted with 1 × 106 cells, as compared to 8% bound to normal kidney cells.

The capacity of the purified, labelled antibodies to bind to intact cells was tested under a variety of conditions. Percent binding increased steeply with cell number and was inversely related to the reaction volume. Binding was faster at 37° C than at 4° C. Non‐specific binding of radioactivity was prevented by carrying out the reaction in the presence of protein. Cells from young cultures bound the labelled antibodies more efficiently than cells from old cultures. The purified, radiolabelled antibodies to the neoplastic cell membrane cross‐reacted to a significant degree with normal hamster liver cells. Antibodies to tumor specific antigens could not be detected by the binding tests, but the presence of such antibodies was suggested by the results of autoradiographic experiments. When treated with labelled antibodies and subjected to autoradiography, only the viral transformed hamster or mouse cells, but not the non‐transformed cells, became labelled. The GA‐treated cells were a highly efficient immunoadsorbent for the purification of antibodies against cell membrane antigens. They maintained their integrity for prolonged periods, were resistant to the reagents used in the elution procedure and could be used repeatedly, up to three times.
Hematopoietic neoplasms in lizards: Report of a typical case in hydrosaurus amboinensis and of a probable case in Varanus salvator
Authors: Zwart P. , Harshbarger J. C.
Published: February 2007

Lymphoreticular proliferative disorders are described in two lizards. The first case, in an East Indian water lizard, Hydrosaurus amboinensis, was classified as a diffuse type of malignant lymphoma of lymphoblastic cell type and is the first known example of a hematopoietic neoplasm in a lizard (class Reptilia; suborder Sauria). The second case, in a Malayan monitor, Varanus salvator, also presented features characteristic of a generalized lymphosarcomatosis, but granulomas associated with a disseminated bacterial infection complicated the picture and precluded an incontestable diagnosis.
Cytotoxic lymphocytes in melanoma patients
Authors: De Vries Jan E. , Rümke Philip , Bernheim Jean L.
Published: February 2007

Peripheral blood lymphocytes from 61 melanoma patients were tested by a microcytotoxicity test for cell‐mediated immunity against melanoma cells. Lymphocytes from 13/25 patients were cytotoxic for autologous tumour cells, while lymphocytes from 31/56 patients were cytotoxic in the allogeneic situation. In the cases tested no cytotoxic reaction was found against autologous or allogeneic normal skin fibroblasts. Normal control lymphocytes were cytotoxic in 2/50 individuals tested. Lymphocytes from patients with other neoplastic diseases showed a positive cytotoxic effect in 1/18 patients tested. In seven cases lymphocytes from melanoma patients, which were cytotoxic for melanoma cells, did not show any cytotoxic effect on plated choriocarcinoma cells. There was no correlation between the presence of specifically immune lymphocytes and the clinical staging of the disease. In the serum of patients with distant metastases, preliminary results indicated the presence of factors which could block the cytotoxic effect of specifically immune lymphocytes.

The data suggest that most malignant melanomas contain a common antigen which is immunogenic in patients with this neoplasm. However, individual‐ or subgroupspecific melanoma antigens may exist. Evidence is found that lymphocytes can lose their capacity to kill melanoma cells in the course of the disease. Change of antigenic expression or sensitivity to the killing effect of lymphocytes during culturing of the melanoma cells may explain the irregularity of some results.
Genetic stability of the sarcoma viruses in murine and avian sarcoma virus‐transformed nonproducer cells
Authors: Stephenson John R. , Scolnick Edward M. , Aaronson Stuart A.
Published: February 2007

Clonal lines of murine and avion sarcoma virus‐transformed mammalian cells, in which the viruses do not productively replicate, were studied for the occurrence of spontaneous or chemical‐induced morphologic reversion. From over 10,000 single‐cellderived clones of MSV‐transformed nonproducer cells examined, only one morphologic revertant was detected. This cell line contained a normal murine sarcoma viral genome, suggesting that it arose as a result of mutation of a cellular gene involved in expression of the transformed state. The frequency of morphologic reversion of avian sarcoma virus‐transformed mammalian cell lines was also investigated. The studies indicate that both murine and avian sarcoma viruses present in transformed nonproducer cells can exist in a genetically stable form.
Translation regulation of catalase synthesis in morris 5123tc hepatoma
Authors: Uenoyama K. , Ono T.
Published: February 2007

Synthesis of catalase by a cell‐free system with the polyribosomes of 5123TC hepatoma was examined. The catalase synthesis by polyribosomes of the hepatoma using a supernatant fraction from the hepatoma itself was as low as one‐tenth of that obtained with the polyribosomes and supernatant fraction from the normal liver. However, the polyribosomes of the hepatoma synthesized catalase to the same extent as did the polyribosomes of normal liver if the supernatant fraction was replaced with that from normal liver or with the pH 5‐fraction prepared from the supernatant of hepatoma.

In addition, catalase synthesis by the polyribosomes and supernatant of hepatoma was activated by the addition of factor (s) purified from the supernatant of normal liver by DEAE cellulose column chromatography. The action of inhibitor (s) in the hepatoma and activator (s) in the normal liver was fairly specific for catalase synthesis, and the syntheses of total protein and albumin were not affected by this/these factor (s) at all.

The possibility that the activator (s) was a messenger RNA for catalase or some species of aminoacyl transfer RNA synthetase and/or transfer RNA, which are lacking in hepatoma, was excluded by the present experiments. Consequently, it was concluded that the polyribosomes of hepatoma contained as much messenger RNA for catalase as did the polyribosomes of normal liver and that the translation for catalase synthesis was inhibited. The role of activating factor (s) was considered to counteract the action of inhibitor in hepatoma.
Effects of sv40 virus on the chromosomes of poikilothermic cells (Gekko gecko) cultivated at different temperatures
Authors: Cohen Maimon M. , Clark H. Fred , Jensen Fred
Published: February 2007

Cells of an established cell line of poikilothermic origin (Gekko gecko) were transformed with SV40 virus and maintained at three temperatures: 23°, 30°, and 35°C. Cytogenetic analysis was undertaken at various times following infection. Increased chromosome damage, related to both incubation temperature and the length of time in culture, was observed in the virus‐transformed cells. A new “tetraploid” stem line arose in those cells cultured at 30°C; the presence of pairs of identical marker chromosomes suggests that this new stem line was derived through endoreduplication rather than the fusion of two cells.
Lymphocyte cytotoxicity reactions to leukemia‐associated antigens in identical twins
Authors: Rosenberg Eugene B. , Herberman Ronald B. , Levine Paul H. , Halterman Roger H. , McCov James L. , Wunderlich John R.
Published: February 2007

Cellular cytotoxicity reactions to human leukemia cells were measured with a sensitive, quantitative assay of cell‐mediated immunity. Freshly explanted leukemia cells, rather than tissue culture cells, were tested to ensure that the antigens detected were not acquired in vitro. Identical twins, one member of each pair having leukemia, were used to minimize genetic variables and histocompatibility differences, thereby providing comparable normal cells to control for the leukemic cells.

Leukemia‐associated antigens were detected on the cells of seven of ten leukemic patients. In no instance was reactivity observed against only the cells of the normal twin. Lymphocytes from three identical twins, seven parents, two siblings and eight normal unrelated individuals were cytotoxic for cells from the leukemic patients but not for cells from these patients' normal identical twins. Lymphocytes from adults had a much higher incidence of reactivity (46%) against the leukemic cells than did the cells of children (9%). Positive lymphocyte cytotoxicity reactions to leukemia‐associated antigens indicate previous sensitization which could have resulted from infection with an environmental agent such as a virus.
Ultrastructural detection of concanavalin surface receptors in normal and in polyoma‐transformed cells
Authors: Martinez‐Palomo Adolfo , Wicker René , Bernhard Wilhelm
Published: February 2007

The ultrastructural distribution of concanavalin A receptor sites on the surface of normal hamster embryo cells and polyoma‐transformed cells was studied by means of the concanavalin‐peroxidase method. In vertical sections of normal cells, the precipitate appeared as a uniform surface layer, which gave the appearance of a homogeneous coat when seen in surface views. The reacting layer on the surface of transformed cells was similar, except in approximately one‐third of the polyoma‐transformed cells. The latter showed a more discontinuous surface layer line in vertical sections, while in tangential sections, the coat was found to be formed by isolated clusters of reacting precipitate. These results indicate that the surface of both normal and transformed cells equally possess exposed binding sites to concanavalin A. The receptors tend to be more irregularly distributed on the surface of some transformed cells.
Membrane immunofluorescence studies on cells producing rat C‐type virus particles
Authors: Pearson Gary , Orr Thomas , Redmon Lena , Bergs Victor
Published: February 2007

The WF‐l rat cell line was investigated for the presence of virus‐associated cell membrane antigens similar to those found in the membranes of cells infected with murine leukemia viruses. These cells transform spontaneously in tissue culture from embryos derived from the Wistar‐Furth ( W/Fu) strain of rats and produce large amounts of rat C‐type virus particles. When sera from W/Fu rats bearing WF‐l tumors were tested for antibodies directed against the WF‐l cells by indirect membrane fluorescence, it was found that 20–35% of the cells reacted strongly. The sera did not react with normal W/Fu embryonic fibroblasts nor did absorption of a pooled positive serum with these cells remove antibodies reactive with the WF‐l cell line. Interestingly, however, these sera also reacted with two other virus‐positive cell lines (R‐35 and RMTL‐8) derived from mammary tumors originating in Sprague‐Dawley rats but not with virus‐negative cell lines. Absorption experiments verified that the R‐35 and RMTL‐8 cells contained cross‐reacting antigens with the WF‐l cells. These results suggested that (a) virus‐associated antigens were expressed in the membranes of cells infected with rat C‐type particles and (b) C‐type virus particles found in cell lines originating from different Sprague‐Dawley rats as well as from the Wistar‐Furth strain were antigenically closely related if not identical.
Metabolic alterations of liver regeneration. VIII. Enhanced synthesis of DNA in the liver of 5‐azacytidine‐treated rats subjected to partial hepatectomy
Authors: Čihák A. , Seifertová M. , Veselý J. , Sorm F.
Published: February 2007

Following 5‐azacytidine, the incorporation of thymidine into DNA in regenerating rat liver is modified depending on the time of drug administration. When given shortly before or after partial hepatectomy, 5‐azacytidine leads to the inhibition of DNA synthesis, while its administration 16–40 h prior to hepatectomy results in its enhancement in 24‐h regenerating liver. The observed alterations in the synthesis of DNA are in agreement with the formation of thymidine 5′‐triphosphate in cell‐free liver extract. The significance of altered DNA synthesis and cytologic changes as revealed with autoradiography is discussed.
Immunofluorescent studies of cultured canine tumor cells
Authors: Bowles C. A. , Hagen W. , Ditmore J. , Kerber W. T. , Woods W. A. , Jensen E. M.
Published: February 2007

The indirect immunofluorescent (IF) test was used in an immunological survey of 17 sera from tumor‐bearing and normal dogs. These sera were reacted against 33 cultured canine tumor and normal cells. A high percentage (70%) of IF positive reactions were seen in cells derived from sarcomatous tumors while only 4% of the cultures from tumor types other than sarcomas and none of the normal cultures reacted with the various sera tested. The fluorescence was seen localized in a paranuclear position with some cells showing cytoplasmic and membrane reactions. The reaction in the sarcoma cells was specific and appeared common within the different sarcoma types. A correlation was demonstrated between the IF positive reactivity and the neoplastic nature of the cells by serial in vivo passage of cultures of a fibrosarcoma and an undifferentiated sarcoma in dogs inoculated while in utero. The various tumor and normal cells examined did not react with antibodies to the gs antigens of the murine or feline leukemia viruses.
Cellular immunity in Wilms' tumour and neuroblastoma
Authors: Kumar S. , Taylor G. , Steward J. K. , Waghe M. A. , Pearson Dorothy
Published: February 2007

Lymphocytotoxicity against tumour‐specific antigens has been examined using cultures of 11 neuroblastomas and 11 Wilms' tumours. The reactivity of lymphocytes from patients with neuroblastomas, Wilm's tumour, other tumours and from normal individuals was examined. In both systems tumour‐specific lymphocytotoxicity was demonstrated in both autochthonous and allogeneic combinations. Cross‐reactivity was observed between Wilms' tumour and hypernephroma but not with respect to other tumours.
An epidemiologic study of oral cancer and precancerous conditions among 101,761 villagers in Maharashtra, India
Authors: Mehta Fali S. , Gupta P. C. , Daftary D. K. , Pindborg J. J. , Choksi S. K.
Published: February 2007

In an extensive epidemiologic house‐to‐house survey, undertaken to study oral cancer and precancerous conditions, 101,761 villagers were examined in the Poona district in the Maharashtra state in India. Besides detection of 12 oral cancers, prevalences were established for leukoplakia (0.67%), preleukoplakia (0.86%), and submucous fibrosis (0.03%). The sample was also studied for chewing and smoking habits, which were practised by 54.4% of the individuals. Among males the most common habit was chewing tobacco with lime, whereas the dominating habit among females was the use of mishri (burned tobacco). The strongest association found was between bidi smoking and mixed habits and leukoplakia. Only a few cases of leukoplakia were found among mishri users. Except for submucous fibrosis it was found that prevalence does not depend on sex if tobacco habits are taken into account.
Cellular reactions against Burkitt lymphoma cells. III. Effector cell activity of leukocytes stimulated in vitro with autochthonous cultured lymphoma cells
Authors: Golub Sidney H. , Svedmyr Erik A. J. , Hewetson John F. , Klein George , Singh Surjit
Published: February 2007

Peripheral blood leukocytes from four patients with Burkitt's lymphoma (BL) were studied for immunological reactions with lymphoblastoid culture line cells. In all four cases peripheral blood leukocytes could reproducibly be stimulated with autochthonous cultured cells derived from tumor biopsies. Stimulation could be accomplished despite the inability of the unstimulated lymphocytes to mediate a cytotoxic response. Leukocytes which have been stimulated with the autochthonous cells displayed strong colony inhibiting activity against the autochthonous BL‐derived target cell, but considerably less activity against two non‐BL‐derived target cells. Autochthonous fibroblasts were ineffective as stimulator cells.
Studies on type‐H virus‐like particles in hamster: Their role in oncogenesis
Authors: Césarini J. P. , de Micco C.
Published: February 2007

Electron microscopic examination of many Syrian hamster cell cultures and of tumours induced in hamsters by oncogenic viruses revealed the presence of virus‐like particles (HVLP). A survey of many lines of hamster cells in primary cultures derived from various tissues of this animal did not show any H VLP. BHK 21/13, tumours induced by the injection of these cells and eleven different clones of BHK 21 transformed in vitro by RNA or DNA oncogenic viruses, contain different amounts of HVLP. These HVLP are associated with A‐type particles in clones transformed by Rous sarcoma virus. Previously published electron microscopic studies of spontaneous tumours induced by different agents (oncogenic viruses, chemical carcinogens, human cancer extracts) have frequently revealed the presence of the same H VLP.

These studies permit some conclusions: (a) H VLP are morphologically distinct from other viral particles; (b) Syrian hamster could be the elective host; (c) the BHK 21 strains and derived clones contain this H VLP; and (d) carcinogenic agents seem to enhance the appearance of those viruses in hamster cells.
Detection of humoral antibody to the transmissible venereal tumour of the dog
Authors: Cohen Dan
Published: February 2007

Humoral antibody against membrane‐associated antigens of the transmissible venereal tumour (TVT) of the dog was demonstrated using the indirect membrane immunofluorescence test. Circulating antibody to the tumour, as well as in vivo coating of the tumour cells with antibody, could be detected at 40 days or more after transplantation. Anti‐TVT activity was contained in the 19S, intermediate S and the 7S fractions of an anti‐TVT serum. No activity was detected in the 3.5S fraction. A cross‐reaction was demonstrated between anti‐TVT sera of clinical cases occurring in Ireland and Malaya.
Cytomegalovirus infections in leukaemic children
Authors: Caul E. O. , Dickinson V. A. , Roome A. P. , Mott M. G. , Stevenson P. A.
Published: February 2007

Twenty‐two children receiving therapy for leukaemia were studied longitudinally for 23 months for cytomegalovirus (CMV) complement fixing (CF) antibodies and excretion. The frequency of CMV antibodies in these children was similar to that of normal children of the same age. During the period of investigation, four patients developed significant (four‐fold or greater) CMV antibody rises. All of these also excreted CMV. Two had seroconversions from negative to positive which were temporally related to the transfusion of fresh blood. Both patients produced CMV‐specific IgM either at the time of the CF rise or immediately before. Two patients with pre‐existing antibody had CF rises. One of these, who had been diagnosed only 2 months previously, had had five transfusions of fresh blood in that period. The second, who had a rise in titre and prolonged excretion of CMV, had had two units of fresh blood one month before the rise occurred. CMV‐specific IgM was not demonstrated in these two patients. Thus all four significant rises in titre followed the transfusion of fresh blood. The IgM results suggest that the two CF seroconversions were primary infections and that the other two significant rises were reinfections or reactivation.

Active CMV infection did not seem to be related to alteration in the leukaemic state or therapy.
Serum‐mediated blocking of cell‐mediated anti‐tumor immunity in a melanoma patient: Association with BCG immunotherapy and clinical deterioration
Authors: Levy Nelson L. , Mahaley M. S. , Day Eugene D.
Published: February 2007

A patient with melanoma was found to have lymphocytes highly cytotoxic for autogenous tumor cells but not for fibroblasts. Autogenous serum did not block the cytotoxicity. He then received an injection of BCG into a small tumor nodule. Three weeks later, in association with accelerated clinical deterioration, his lymphocytes were still cytotoxic, but his serum could now block completely the tumor‐specific lymphocyte reactivity.
Intensive chemotherapy in patients with generalized Burkitt's lymphoma
Authors: Ziegler John L. , Bluming Avrum Z. , Magrath Ian T. , Carbone Paul P.
Published: February 2007

The results of a clinical trial in patients with generalized Burkitt's lymphoma using either multiple doses of cyclophosphamide or a cyclic, sequential regimen employing cylophosphamide, vincristine, methotrexate, and cytosine arabinoside (TRIKE) are reported. Of 42 evaluable patients 24 received cyclophosphamide and 18 received TRIKE. No significant differences were encountered between either group with respect to remission induction, relapse rate or survival. Remission duration was significantly prolonged in the patients receiving cyclophosphamide, but this event has little effect on survival. Although intensive chemotherapy is probably necessary in patients with generalized Burkitt's lymphoma, other variables such as meningeal involvement and immunologic factors appear to affect relapse and survival.
Carcinoembryonic antigen (CEA) in gastrointestinal and extragastrointestinal tumors and its relationship to tumor‐cell differentiation
Authors: Denk H. , Tappeiner G. , Eckerstorfer R. , Holzner J. H.
Published: February 2007

Carcinomas of gastrointestinal (colon, stomach, pancreas, liver) and of extragastrointestinal (bronchus, breast, tonsil, anus, ovary) origin and normal large‐bowel mucosa were studied by indirect immunofluorescence for the presence of the carcinoembryonic antigen (CEA). In addition, an attempt was made to correlate the CEA content of the tumors with the degree of their cellular differentiation. In well‐differentiated tumors of the colon, including hypersecretory well‐differentiated mucoid carcinomas, CEA was abundant on the luminal tumor cell surface and in the lumina of the glands. In moderately differentiated ones, CEA was present in rather low concentrations on the luminal surface and in secondary glandular structures. In poorly differentiated anaplastic carcinomas, CEA was absent. In non‐cancerous colonic mucosa surrounding the tumor, in colonic mucosa distant from the tumor as well as in colonic mucosa taken at autopsy from subjects with non‐neoplastic extragastrointestinal diseases, CEA could not be found by indirect immunofluorescence. The CEA content of gastric carcinomas was lower than in colonic tumors, although the distribution was similar. In pancreatic cancers, CEA was present in variable amounts depending upon the differentiation of the individual tumor. In these malignancies, CEA was found not only on the luminal surface and in the lumina, but also in the cytoplasm of isolated tumor cells. CEA was not detected in carcinomas of extragastrointestinal origin by indirect immunofluorescence. The localization of CEA on the surface (probably glycocalyx) of the cell, together with its dependence upon a certain degree of tumor cell differentiation, suggest that CEA is a secretion product rather than a constituent of the tumor cell membrane.
Incidence of spontaneous neoplasms in breeding and retired breeder BALB/cCr mice throughout the natural life span
Authors: Peters Robert L. , Rabstein Louise S. , Spahn Gerard J. , Madison Russell M. , Huebner Robert J.
Published: February 2007

Large populations (approximately 1,300 from weaning to 10 months and 4,500 at 10 to 12 months of age) of BALB/cCr mice were observed throughout the remainder of their natural life span to determine the age‐specific incidence of various spontaneous neoplasms. Over 2,000 mice were necropsied and their tissues examined microscopically. Neoplasms of all types were rare prior to 1 year of age, but an early life (1‐6 months) “peak” of acute lymphocytic leukemia was noted. The incidence of lymphatic neoplasms increased until about 24 months of age and then declined. The incidence of other types of tumor, including reticulum cell neoplasms, mammary and other epithelial tumors, mesenchymal tumors (non‐hematopoietic) and benign tumors increased progressively with increasing age. Mammary tumors, myoepitheliomas, hemangioendotheliomas and fibrosarcomas were the most prevalent solid tumor malignancies. Reticulum cell neoplasms were the most frequent malignant neoplasms of the hematopoietic system. Pulmonary alveologenic and adrenocortical adenomas were the most common tumors among those classified histologically as benign.
Prevalence of the group‐specific (gs) antigen and infectious virus expressions of the murine C‐type RNA viruses during the life span of BALB/cCr mice
Authors: Peters Robert L. , Hartley Janet W. , Spahn Gerard J. , Rabstein Louise S. , Whitmire Carrie E. , Turner Horace C. , Huebner Robert J.
Published: February 2007

The prevalence of C‐type RNA tumor‐virus gs antigen and infectious virion expression was determined at various ages throughout the life span of the BALB/cCr mouse. The incidence of gs antigen was low (2.5%) prior to 6 months of age, but increased progressively to 71% in mice over 24 months of age. The incidence of infectious virus isolated in mouse embryo cell culture was low (10%) prior to 6 months of age, but rose rapidly after 6 months of age and remained relatively stable (varying from 46% to 62%) throughout the remainder of life. Eighteen of nineteen isolations made prior to 1 year of age were made on NIH Swiss mouse embryo cells as opposed to BALB/c mouse embryo cells (1/19). In older mice, isolations on BALB/c cells increased, but only after 24 months of age were isolation rates higher than on NIH Swiss cells. Isolations from the spleens of mice with malignancies were somewhat more frequent than from spleens of mice which were normal or had histologically benign tumors.
Dependence of the specificity of the serologic test for primary liver cancer in different areas of the world on sensitivity of the method used for detecting alpha‐fetoprotein
Authors: Elgort D. A. , Abelev G. I. , O'Conor G. T.
Published: February 2007

A comparative investigation was made of the diagnostic value of the AFP test as dependent on sensitivity of the method used for detecting AFP. Patients' sera, collected from five African countries, from Singapore, Jamaica, and the USSR, and checked earlier by the standard AFP test (agar‐gel precipitation technique) were reexamined using the method of indirect immunoradioautography. The latter method is 30 to 50 times more sensitive than the standard AFP test.

As a result the percentage of hepatomas revealed serologically was increased for Africa from 75% to 89.2% and for the USSR from 64% to 87.1% (among histologically proven cases). The diagnostic specificity of the test became significantly lower: a great number of AFP‐positive cases was observed in the control group. The proportion of such “false‐positive” cases is not equal in different parts of the world: 22.6% in Africa and 6.0% in the USSR. Great differences were also observed between African countries, from 7.8% in Uganda to 45.1% in Congo. It is suggested that these variations are related to the existence of a “background” AFP level in healthy people, which may be different in various populations depending on genetic and nutritional factors. The differences may be a reflection of varying predisposition to cancer of the liver.
Human cancer in households containing cats with malignant lymphoma
Authors: Schneider Robert
Published: February 2007

Since feline malignant lymphoma is viral in nature, a retrospective case‐control study was done to assess if there was any additional risk of cancer for human members in households with cats histologically diagnosed as having that disease. The 221 households identified as having owned cats that developed the disease were matched with control ones on the basis of index cat age, sex and breed. Various compared human demographic factors indicated close agreement in makeup between groups. Tests for association of human cancer with feline malignant lymphoma were negative. Association was sought in two ways: (1) by a case‐control comparison, controlling human household cancer risk and length of time the index cat was in the household; and (2) by a comparison of the last five years' occurrence of human cancer in both groups compared to the expected. The expected numbers were calculated for the population‐at‐risk from human age‐ and sex‐specific incidence rates published for this area. The specific occurrence of human cancers of the lymphatic and hematopoietic systems was examined. The validity of the study results and extension of these results to cat ownership in general were discussed.
α‐fetoprotein and hepatocarcinogenesis in rats fed 3′‐methyl‐4‐(dimethylamino)azobenzene or n‐2‐fluorenylacetamide
Authors: Kitagawa Tomoyuki , Yokochi Taeko , Sugano Haruo
Published: February 2007

Serum α‐fetoprotein (af) of rats during hepatocarcinogenesis by 3′‐methyl‐4‐(dimethylamino)azobenzene (3′‐Me‐DAB) or N‐2‐Fluorenylacetamide (FAA) was checked by the micro‐Ouchterlony method throughout the course of the study. The serum af appeared in two phases, early from the 3rd to 5th week and late during the development of large carcinomas.

The frequency of early appearance of serum af varied considerably according to the difference in age, sex, and strain of the animals or the difference in type or dose of the carcinogen. In general, 3′‐Me‐DAB was a much stronger carcinogen than FAA in producing early serum af. A good correlation was observed between the serum af level and the intensity of oval cell proliferation in the liver at this stage.

The cell composing the nodular hyperplasia in 3′‐Me‐DAB or the area of hyperplasia in FAA carcinogenesis, which replaced the major part of the liver in the next stage and had been considered the most possible forerunner of the carcinoma, did not seem to produce af.

The serum af in the late phase was produced by the carcinoma. The majority of the 3′‐Me‐DAB‐induced carcinomas belonged to the mixed type carcinoma. This type of carcinoma was strongly af‐producing with the required minimal size of 10 mm in diameter for positive serum af. Most of the FAA‐induced carcinomas were of the trabecular type. This type of carcinoma was relatively weak in af‐production and the serum af was negative until a trabecular carcinoma became larger than 20 mm in diameter.

The appearance of early serum af was distinct evidence of a fair progress of hepatocarcinogenesis, and a positive correlation was found between the degree of this phenomenon and the frequency of development of a carcinoma producing large amounts of af. However, the appearance of early serum af was not an absolute requisite for later development of carcinomas.
Cellular immunity to human breast carcinoma
Authors: Fossati Giuseppe , Canevari Silvana , Porta Giuseppe Della , Balzarini Gian Paolo , Veronesi Umberto
Published: February 2007

An in vitro microassay technique was used to study the cellular immunological response of 16 breast carcinoma patients against tumor‐associated antigens. The in vitro growth of target cells was achieved with five pleural effusions of patients with breast carcinoma infiltration of the pleura.

The lymphocytes obtained from the peripheral blood of three of the five target cell donors had a specific killing effect on autochthonous cancer cells. The lymphocytes of nine of the 13 other patients killed at least one of the target tumor‐cell lines. No cyto‐toxicity was observed with the lymphocytes of five out of six patients with a benign lesion of the breast, of three patients with a carcinoma other than of the breast, and of one patient without tumor.
The distribution of cancer within the large bowel
Authors: de Jong U. W. , Day N. E. , Muir C. S. , Barclay T. H. C. , Bras G. , Foster F. H. , Jussawalla D. J. , Kurihara M. , Linden G. , Martinez I. , Payne P. M. , Pedersen E. , Ringertz N. , Shanmugaratnam T.
Published: February 2007

The distribution of cancer of the anatomical sub‐sites of the colon and rectum in Alameda County (California), Bombay, Denmark, Kingston and St Andrew (Jamaica), Miyagi Prefecture (Japan), New Zealand, Norway, Puerto Rico, Saskatchewan (Canada). Singapore, The South Metropolitan Cancer Registry (SMCR) (England), and Sweden were analysed. In this series, the highest rates for large‐bowel cancer are found in North America and New Zealand; the lowest in the East (Japan, Bombay and Singapore) and the Caribbean, while intermediate rates prevail in Scandinavia and England.

The pattern of sub‐site distribution of the cancers throughout the large bowel is similar in areas of high and intermediate risk; namely, there is a decreasing incidence from ascending colon towards the descending colon with a sharp increase in incidence at the sigmoid colon, the rates for rectum being in turn higher than those for the sigmoid. In low‐incidence areas, the general pattern is the same, but there may be a deficit of sigmoid cancers. This remains to be proved. Denmark shows a significant excess of lower rectum cancer, particularly in males. The age‐standardized incidence rates for rectum cancer in this registry are higher than in any of the others, although the rates for other parts of the large intestine in Denmark are in the intermediate range. This finding should be exploited.

With advancing age, the sex ratio for colon cancer as a whole shows a higher male risk; this male excess is, however, confined to the descending and sigmoid colon. The sex ratios for ascending and transverse colon cancer do not change with advancing age, while those for the sigmoid, and to a lesser extent the descending colon, do. Rectal cancer is commoner in males, the male preponderance becoming more pronounced after 65 years of age. For descending, sigmoid and rectal cancers, incidence increases more steeply with age in males than in females, the incidence‐age curves on a log‐log scale tending to have a downward curvature for the older age‐groups. The slopes for ascending and transverse colon cancer do not differ between the sexes and their age‐incidence curves have an upward curvature, particularly in women. It makes little difference to the incidence rates whether cancers of the recto‐sigmoid are included in the rectum or the colon.

The findings are discussed in the light of current aetiological theories. The results are consistent with the sub‐site risk being related to the rate of transportation of colonic content. Transportation rates in the variety of risk situations need to be investigated, with particular attention being paid to the sigmoid in low‐risk areas.
Evaluation of the carcinogenic activity of the hydroxymethyl derivatives of 7,12‐dimethylbenz(A) anthracene by an in vitro‐in vivo technique
Authors: Flaks A. , Hamilton J. M. , Clayson D. B. , Sims P.
Published: February 2007

7,12‐Dimethylbenz(a)anthracene and three of its metabolites were tested for carcinogenic activity by in vitro incubation with murine pulmonary tissue for 2 days followed by implantation of the explants into isologous mice. 7‐Hydroxymethyl‐12‐methylbenz(a) anthracene and 12‐hydroxymethyl‐7‐methylbenz(a) anthracene were as potently carcinogenic as the parent hydrocarbon but 7,12‐dihydroxymethylbenz(a)‐anthracene was inactive. These results are discussed in the light of current theories of metabolic activation of the hydrocarbon.
Serum alpha‐fetoprotein. VIII. Serum levels during diethylnitrosamine poisoning of baboons
Authors: Purves L. R.
Published: February 2007

Serum alpha‐fetoprotein levels rise during various stages of poisoning of baboons with diethylnitrosamine before the induction of any liver tumours. The possible mechanisms causing raised AFP levels in people from primary liver cancer high‐risk areas are discussed in the light of these experimental toxicity studies on baboons.
Surface antigen and polypseudopodia in abortive transformation of BHK 21 cells by polyoma virus
Authors: Stoker M. G. P. , Thornton Maureen , Riddle P. , Birg Françoise , Meyer G.
Published: February 2007

When BHK 21 cells are exposed to high multiplicities of polyoma virus, a change in surface antigen may be detected by immunofluorescence, beginning at 18 h and affecting up to 88% of cells 24 h after infection. Time‐lapse cinematography shows that there is a concurrent change in movement and shape (polypseudopodia) of the cells in the confluent layer, involving about the same proportion of cells. Both these changes appear before the virus‐induced stimulation of the thymidine incorporation and mitosis, and before the increase in lectin agglutinability. The S antigen disappears more rapidly than the polyspeudopodia in these abortively transformed cells, but both persist in stably transformed cells. The antigenic change and polyspeudopodia are not the result of the virus‐induced stimulation of cell DNA synthesis and mitosis, but it is not yet possible to say if they are an essential requirement for this stimulation.
Re‐exposure of human lymphoblastoid cell lines to Epstein‐Barr virus
Authors: Diehl Volker , Wolf Hans , Schulte‐Holthausen Heinrich , Hausen Harald Zur
Published: February 2007

Human lymphoblastoid lines of various origins which harbour Epstein‐Barr virus (EBV)‐specific nucleic acid were re‐exposed to EBV. Following infection, cells of the non‐virus‐producing lines, Raji and S 95, predominantly synthesized EBV‐specific early antigens (EA), whereas only a small percentage of cells revealed viral capsid antigens (VCA). In Raji cells, the number of VCA‐producing cells was paralleled by the percentage of virus‐specific DNA‐synthesizing cells. In S 95 cells, however, viral DNA‐synthesizing cells exceeded the number of VCA‐producing cells by a factor of more than 10. Induction of EA in Raji cells was dose‐dependent and inversely related to cell growth. Irradiation of the virus by ultraviolet light prior to infection led to reduced infectivity. This reduction seemed to follow single‐hit kinetics. Raji cells, previously re‐exposed to EBV, showed reduced EA induction after re‐infection with EBV, as compared to Raji control cells not previously exposed. Of 10 lines which spontaneously synthesize EBV‐specific antigens, seven lines proved to be refractory to re‐infection, whereas three were as susceptible as the Raji and S 95 controls. From three of the refractory lines infectious virus could be recovered from the culture medium prior to infection.

These results permit the following interpretations: (1) the response of human lymphoblastoid cells after re‐infection with EBV results from the infecting virus and not from stimulation of endogenous genomes; (2) cells demonstrating EA synthesis ultimately die; (3) re‐exposure to EBV increases the resistance to re‐infection of the surviving cells; and (4) cell lines producing infectious EBV are refractory to re‐infection. It is suggested that the spontaneous synthesis of infectious virus favours the selection of resistant cells.
Burkitt's lymphoma in Ghana: Clinical features and response to chemotherapy
Authors: Nkrumah Francis K. , Perkins Ida V.
Published: February 2007

The clinical presentation, response to chemotherapy, relapse pattern and prognosis in Burkitt's lymphoma were evaluated in a prospective manner in 54 patients. Cyclophosphamide induced complete clinical remission in over 75% of the patients irrespective of stage of the disease. Long‐term sustained remissions, however, were mostly obtained in patients with localized disease (stage I‐II). Patients with abdominal tumours (stage III), though showing good initial response to chemotherapy, had a high relapse rate, Intrathecal methotrexate transiently normalized cerebrospinal fluid cell counts in patients with malignant pleocytosis (stage IV). Early meningeal relapse was the rule and the patients did very poorly. Fifteen of the 54 patients have remained tumour‐free and without recurrence for periods ranging from 1 to 2 years. Three patients who had tumour recurrences are also at present tumour‐free after retreatment. Early tumour relapse was usually associated with a poor prognosis. The calculated long‐term survival rate for all patients in the series was 33.1%.
Growth regulation and tumour formation of normal and neoplastic rat cells
Authors: Weiss Robin A. , Veselý Pavel , Sindelařova Jitka
Published: February 2007

The oncogenicity of cells in syngeneic hosts was compared to the regulation of cell growth in vitro. Normal embryonic fibroblasts (LWF cells) were not tumorigenic. Spontaneously “transformed” fibroblastic cells (LW13 cells) and Rous‐transformed epithelioid cells (RsK4 cells) grew into sarcomas on subcutaneous or intravenous inoculation. TD50 varied according to the route of administration and dispersion of the cells. Rous‐transformed cells gave rise to tumours with a short latent period while the spontaneously transformed cell line showed a biphasic latent period. The histopathology of the two kinds of tumours was similar, with a higher tendency to pleomorphism in the Rous tumours. Normal fibroblasts had low plating efficiency on plastic or in soft gel suspension. LW13 cells plated with high efficiency on plastic but poorly in suspension, and RsK4 cells plated with high efficiency in both situations. Normal cells were highly sensitive to topoinhibition, LW13 cells were moderately sensitive, while LW13 cells explanted from tumours and RsK4 cells were the least sensitive. However, values of topoinhibition and its compensation by serum were themselves found to vary with cell density. RsK4 cells initiated DNA synthesis in low serum medium but normal cells and LW13 cells did not. Neither LW13 nor RsK4 cell proliferation was inhibited by contact with confluent, static 3T3 cells or normal LWF cells. With the cell types examined here an association exists between contact inhibition of cell movement and topoinhibition of growth. The degree to which altered cells respond to the regulatory contact signals of normal cells appears to be the best in vitro indicator of oncogenicity.
TRANSITORY CELL ANTIGENS OF RAT LIVER. III. THE REAPPEARANCE OF α‐FETOPROTEIN DURING CHEMICAL CARCINOGENESIS
Authors: De Et B. Néchaud , Uriel J.
Published: February 2007

When rats were fed a basal diet containing 0.01 to 0.04% 3′‐methyl‐4‐dimethyl‐aminoazobenzene (3′DAB), no serum α‐fetoprotein (αFP) was detected by gel immunodiffusion techniques during the first month of ingestion. On the contrary, with 0.06% 3′DAB in the same basal diet, α‐FP was detected after only two weeks in the sera of almost all animals, irrespective of age at the onset of feeding. An even earlier “reappearance” of α‐FP was observed with the hepatocarcinogen dimethylnitrosamine, given in drinking water. However, the frequency of α‐FP reappearance was dependent on the age of the animals when treatment was begun. Once detected, the α‐FP persisted in the blood for some time and was independent on the continued administration of carcinogen. The reappearance was characterized by several waves of α‐FP secretion over a given period. Animals whose serum α‐FP level became stabilized had a high probability of developing an hepatocellular carcinoma. Nevertheless, in 30% of hepatoma bearing animals, α‐FP could not be detected. Administration of the basal diet either alone or supplemented with 0.06% of the non‐carcinogenic 4′‐methyl‐4‐dimethylamino‐azobenzene also resulted in α‐FP reappearance. However, here the reappearance took place later and at a frequency equal to or lower than 30%. In the light of the above results, the reported specificity of the association between serum α‐FP and primary liver cancer should be reconsidered, at least during the early stages of the neoplastic transformation.
Destruction of cultivated melanoma cells by lymphocytes from healthy black (North American Negro) donors
Authors: Hellström I. , Hellström K. E. , Sjögren H. O. , Warner G. A.
Published: February 2007

Peripheral blood lymphocytes from healthy Black (North American Negro) donors were found to be cytotoxic to cultivated malignant melanoma cells (7 out of 9 tested), but not to tumor cells of other types or to normal skin fibroblasts, in experiments using lymphocytes from normal White donors and from White patients with other types of tumor as controls. Lymphocytes from normal Blacks thus behaved similarly to lymphocytes from patients having melanomas. The cytotoxic effect could be blocked by sera from patients with progressively growing melanomas. Sera from some healthy Black donors could abrogate (“unblock”) the blocking effect of sera from patients with growing melanomas (four out of four tested).
Effect of 3‐methylcholanthrene and dimethylnitrosamine on anchorage dependence of rat fibroblasts chronically infected with rauscher leukemia virus
Authors: Mishra Nirmal K. , Ryan Wayne L.
Published: February 2007

This report describes the loss of anchorage dependence (AD–) after treatment with 3‐methylcholanthrene or dimethylnitrosamine in rat embryo fibroblasts which normally exhibit anchorage dependence (AD+). The AD+ fibroblasts which were chronically infected with Rauscher leukemia virus showed the highest frequency of transformation to AD– cells with chemical carcinogen treatment. A small percentage of AD– cells also appear in uninfected control cells treated with dimethylnitrosamine or at much higher frequency with 3‐methylcholanthrene. The virally infected cells also showed a detectable level of transformation to AD– cells without added chemicals. However, the combined effects of Rauscher leukemia virus infection and chemical carcinogen treatment were much greater than the additive effect of the two. No clear correlation between AD– transformation and the ability to grow in factor‐free medium was found. The significance of these observations is discussed in relation to the “oncogene” hypothesis.
Effects of BCG on various facets of the immune response against polyoma tumors in rats
Authors: Bansal S. C. , Sjögren H. O.
Published: February 2007

Administration of BCG at the time of rat polyoma tumor isografting or 2 weeks previously, inhibited tumor growth and induced an increased level of lymphocyte cytotoxicity and an increase in the number of circulating lymphocytes, i.e. it resulted in an increased level of cell‐mediated immunity. A similar inoculation of BCG at the time when the tumor isograft had already grown out to a palpable nodule did not inhibit tumor growth, but rather caused an enhanced growth. It did not increase the level of cell‐mediated immunity under these conditions and did not decrease the blocking activity in serum, but rather increased it. Furthermore, it did not induce any production of cytotoxic antibodies detectable with rat complement. BCG treatment of rats which had the same day undergone incomplete tumor excision increased the growth of remaining tumor and increased the blocking activity in serum. On the other hand, BCG treatment of analogous rats which had received “unblocking treatment” in the form of splenectomy and inoculation of unblocking serum caused tumor regression in some animals and increased the cell‐mediated immunity in all animals tested.