bluuebunny/crossref_metadata_2025_split huggingface dataset:
The occurrence of feline leukaemia virus neutralizing antibodies in cats
Authors: Russell Peter H. , Jarrett Oswald 
Published: February 2007

AbstractThe prevalence of feline leukaemia virus (FeLV)‐neutralizing antibodies to subgroups A (FeLV‐A), B (FeLV‐B) and C (FeLV‐C) was determined in four populations: specific pathogen‐free (SPF) cats; urban and suburban free‐range cats; cats from FeLV‐infected multiple cat households (MCHs); and cats with leukaemia. The prevalence of anti‐FeLV‐A antibodies was closely related to the frequency of isolation of FeLV‐A in each population, except in leukaemic cats. Thus, antibody was found in none of the SPF cats, in 4% of free‐range cats and in 42% of the cats in MCHs. In individual cats in MCHs there was a strong correlation between the presence of antibodies to FeLV‐A and the absence of an active FeLV viraemia. Anti‐FeLV‐B antibodies were encountered less frequently although FeLV‐B was present in about half of the FeLV isolates. It is likely that this was due to the restricted growth of FeLV‐B in cats. Surprisingly, in view of the very rare isolation of FeLV‐C, the prevalence of anti‐FeLV‐C antibodies was high: 11% in free‐range, 51% in MCH and 40% in leukaemic cats. None were found in SPF cats. The occurrence of these, unlike antibodies to FeLV‐A, was not related to whether or not a cat was viraemic. The relationship between the development of neutralizing antibodies and persistent viraemia was studied in experimental infections of cats with FeLV by inoculation or contact. The outcome of the infection was determined soon after infection. All of the classes of cats which were found in the epidemiological survey were observed in these experiments.
Aryl hydrocarbon hydroxylase in persons with lung or laryngeal cancer
Authors: Ward Elizabeth , Paigen Beverly , Steenland Kyle , Vincent Ronald , Minowada Jun , Gurtoo Hira L. , Sartori Pam , Havens Mary Bohne 
Published: February 2007

AbstractTo test whether the distribution of AHH inducibility is shifted toward the high end of the range in patients who had lung and laryngeal cancer, we measured this trait in 59 patients (32 lung and 27 laryngeal) who had resectable tumors and had been disease‐free for a period of time. The advantage of selecting patients who were free of clinical disease was that measurement of their AHH inducibility should not have been affected by the disease state. Patient and control populations showed no difference in basal and induced AHH activity or AHH inducibility. The mean AHH inducibility in patients who had lung cancer was 3.20±0.20; in patients who had laryngeal cancer 2.96±0.18, and for all controls 3.29±0.04 (no significant difference at p = 0 05). Further analysis of the distribution of AHH inducibility in the patient group compared to controls showed no suggestion of a shift toward the higher end of the range in patients who had lung and laryngeal cancer.
Interferon and spontaneous cytotoxicity in man. I. Enhancement of the spontaneous cytotoxicity of peripheral lymphocytes by human leukocyte interferon
Authors: Einhorn Stefan , Blomgren Henric , Strander Hans 
Published: February 2007

AbstractA purified preparation of human leukocyte interferon used at this hospital in the treatment of malignant diseases was tested for its ability to modify the spontaneous cytotoxicity of peripheral lymphocytes from healthy donors. The inhibitory effect of allogeneic lymphocytes on the [3H]thymidine incorporation of a lymphoblastoid cell line, Raji, was augmented by the presence of interferon or by pretreatment of the lymphocytes with interferon. This form of pretreatment also increased lymphocytes' capacity for reducing the number of surface‐adherent tumor cells in a microassay. Moreover, lymphocytes treated with interferon exhibited an enhanced cytotoxic capacity for target cells on incubation with such cells labelled with 51Cr.
The circulating alpha subunit of human chorionic gonadotrophin in gynacologic tumours
Authors: Rutanen Eeva‐Marja 
Published: February 2007

AbstractThe circulating levels of the immunoreactive alpha subunit of glycoprotein hormones were measured by the hCG alpha subunit radioimmunoassay in 101 patients with non‐trophoblastic gynaecological cancer and in 164 serum samples obtained from 10 patients with choriocarcinoma and five patients with hydatidiform mole. Serum samples from six patients with choriocarcinoma and four with hydatidiform mole were further examined for the existence of free alpha by chromatography on a calibrated Sephadex G‐100 column. In patients with non‐trophoblastic cancer the immunoreactive alpha subunit levels were not different from those of controls in the corresponding age groups. In trophoblastic disease all hCG‐positive samples showed also alpha subunit immunoreactivity when tested by radioimmunoassay, but no isolated alpha elevation was found. Chromatographic analyses revealed free alpha subunits in three out of six patients with choriocarcinoma and two out of four patients with hydatidiform mole. A patient who eventually died of choriocarcinoma was carefully followed for the free alpha secretion, and no alpha elevation was found in any of the 16 serum samples taken at various phases of disease. The present study shows that, unlike pancreatic islet cell tumours in vivo and HeLa cells in vitro, non‐trophoblastic gynaecologic cancer in vivo does not appear to have any significant alpha secretion. In trophoblastic disease free alpha subunits may coexist with native hCG more frequently than it was originally assumed, but no isolated alpha secretion could be demonstrated. The intriguing disparity between the alpha secretion by normal and abnormal trophoblasts was confirmed in this study, but the biological basis and significance of this phenomenon remain obscure.
BCG treatment of transplanted rat tumours of spontaneous origin
Authors: Pimm M. V. , Cook A. J. , Hopper D. G. , Dickinson A. M. , Baldwin R. W. 
Published: February 2007

AbstractSix transplanted rat tumours (three mammary carcinomas and three fibrosarcomas), all of spontaneous origin and of limited immunogenicity, have been examined for susceptibility to immunotherapy with BCG (Glaxo). Growth of limited numbers of cells from five tumours was suppressed when cells were injected subcutaneously in admixture with BCG organisms. There was no clear correlation between the immunogenicity of tumour lines and their susceptibility to regionally applied BCG. Active specific immunotherapy, using vaccines of viable or radiation‐attenuated tumour cells in admixture with BCG, was reproducibly successful with only one tumour, the mammary carcinoma Sp4, this being the most immunogenic of the tumours examined. These studies indicate that naturally arising tumours are less susceptible to BCG‐mediated suppression than carcinogen‐induced tumours widely used for experimental immunotherapy, but indicate that local application of BCG may give the best therapeutic response.
Longitudinal studies of chromosomal abnomalities and reticulum cell proliferation in new zealand black mice
Authors: Friedman J. M. , Fialkow Philip J. , East June , Bryant Jean I. , Salo Armi C. 
Published: February 2007

AbstractA longitudinal study of 40 New Zealand Black (NZB) mice and 20 BALB/c control animals was performed. A significant association was observed between the presence of acquired spleen‐cell aneuploidy at some time during life and development of histological evidence of reticulum‐cell neoplasia in individual animals. This finding is compatible with the hypothesis that aneuploid clones which arise in the spleens of aging NZBs are at least potentially neoplastic. However, no relationship between histologically neoplastic reticulum cell proliferation and aneuploidy was apparent in single splenic specimens obtained from NZB mice of various ages. This lack of association indicates that failure to detect chromosomal abnormalities on direct study of cells from a tumor cannot be taken as evidence that the neoplastic cells themselves lack such abnormalities.
An immunoregulatory factor associated with spleen cells from tumor‐bearing animals. I. Effect on tumor growth and antibody production
Authors: Isakov Noah , Segal Shraga , Hollander Nurit , Feldman Michael 
Published: February 2007

AbstractAn immunopotentiating factor associated with spleen cells of C57BL/6J mice bearing the 3LL tumor is described. Supernatants of cultured spleen cells from tumor‐bearing mice (TBM) augmented the generation of both 19S and 7S antibody‐producing cells, when injected with sheep erythrocytes into syngeneic C57BL/6J mice. The enhancing supernatant acted both as a polyclonal activator, when injected in the absence of antigen, and as a potentiator of specific antigen‐dependent humoral immune responses, when injected in the presence of antigen. It was found to augment induction of specific memory, but not memory expression. Concomitantly with their influence on humoral immune responses, TBM spleen cell supernatants enhanced tumor growth when injected, mixed with 3LL tumor cells, into syngeneic recipients. The secretion of a factor which augments antibody production was not confined to the 3LL tumor system. Spleen supernatants of C47BL mice carrying the B16 melanoma and those of C3H mice carrying the KHT sarcoma had a similar effect on antibody production. These findings suggest that an immunoregulatory factor(s) appears in spleen cells of TBM as a result of their interaction with the neoplastic tissue. This factor can potentiate production of antibodies, possibly also against tumor‐associated antigens. The relevance of the immunopotentiating effects of such factor(s) to tumor growth is discussed.
The early appearance and subsequent distribution of murine leukaemia virus in NZB embryos
Authors: East June , Tilly Rita J. , Tuffrey Mauren , Harvey Jennifer J. 
Published: February 2007

AbstractInformation concerning both spontaneous autoimmune haemolytic disease and a uniquely high expression of solely xenotropic murine leukaemia virus (MuLV) is transmitted genetically in New Zealand Black (NZB) mice. The actual production, location, and dissemination of MuLV has now been monitored in NZB embryos by electronmicroscopy, which is the most suitable method for detecting such virus very early in prenatal life i.e. in eggs before they become implanted approximately 4 1/2 days after mating. A systematic search was made for intracisternal type‐A and type‐C virus particles in NZB embryos from the one‐cell stage to the 14th day of gestation. AKR, Balb/c, and F1 (BALB/cx NZB) eggs were included for comparison of preimplantation phases, and five combinations of blastocysts fused in vitro as 6‐ to 8‐celI eggs were also examined. Four variants of type‐A particles were distinguished, characteristically associated with the cisternae of the endoplasmic reticulum. All replicated at some stage of preimplantation development in NZB and AKR eggs, as well as in fused AKRAKR and BALB/c↔BALB/c blastocysts, and three of them were still to be found in 8‐ or 14‐day NZB embryos. Moreover, the smallest type‐A variant also appeared in one‐cell unfertilized NZB eggs, indicating that its production did not depend on the stimulus of fertilization. No type‐A virus was identified in normal BALB/c and F1 (BALB/cx NZB) blastocysts, or in NZBB́LB c, CBA/H‐T6CBA/H‐T6, and AKRCBA/H‐T6 combinants. By comparison, immature type‐C virus was first seen in 5‐day NZB implants. But it was not possible to decide whether implantation or a particular stage of differentiation determined its emergence, or whether it had only then reached detectable levels. Thereafter, immature C and type‐A particles coexisted and replicated until at least the 14th day of gestation, but mature C virus was not evident at this age. Both ecotropic and xenotropic MuLV can be represented morphologically as type‐C particles. The known lack of infectivity of the type‐A particles, coupled with our evidence of their genetic transmission and of their ubiquity in NZB embryos which do not harbour ecotropic Mulv, could indicate that they, too, are xenotropic. Coincidentally, huge numbers of immature and mature type‐C MuLV were found distending the uterine glands of pregnant NZB females carrying 5‐ or 7‐day implants. But a similarly extravagant picture was seen in agematched NZB virgins. These findings are to be investigated further.
Leukocyte migration inhibition responses in canine lymphosarcoma
Authors: Onions D. E. , Owen L. N. , Bostock D. E. 
Published: February 2007

AbstractThe leukocyte migration inhibition (LMI) responses of 16 cases of canine lymphosarcoma were assessed at several stages of a combined chemotherapy immunotherapy regime. Pooled allogeneic lymphosarcoma cells used in treatment together with other allogeneic lymphosarcoma cells and autochthonous tumour cells were employed as antigens. Positive inhibitions were detected at all stages of treatment when medium controls were used but were not detected in five normal dogs with the same control. There was no association between relapse and remission and LMI response. When a normal lymph‐node cell control was used only four dogs produced positive responses, all of which occurred after allogeneic cell administration. These positive responses could not be completely accounted for by sensitization to histocompatibility antigens but as they occurred both in remission and in relapse, including very advanced cases necessitating euthanasia, they were of no value in determining prognoses.
Study of epstein‐barr virus‐determined nuclear antigen (EBNA) by chromatography on fixed cell nuclei
Authors: Hirsch Ivan , Suchánková Alena , Závadová Hana , Vonka Vladimír 
Published: February 2007

AbstractLow ionic strength (50 to 100 mM NaCl) and pH 6.0 were found to be optimal conditions for in vitro conversion of Epstein‐Barr virus (EBV)‐determined nuclear antigen (EBNA)‐negative nuclei to EBNA‐positive nuclei by addition of the complement‐fixing (CF) antigen extracted from Raji cells. In vitro conversion of nuclei to EBNA‐positivity was sensitive to DNase but not to RNase treatment. This suggests that nuclear DNA is a specific target substance to which EBV‐CF antigen binds. If nuclei were fixed with methanol/acetic acid and subsequently treated with 0.6 M NaCl, EBNA could be eluted from in vitro‐converted Ramos nuclei with 0.3 and 0.4 M NaCl. The same conditions were also found to be optimal for the adsorption and elution of EBV‐CF antigen in DNA‐cellulose chromato‐graphy. This indicates that the DNA‐binding properties of EBNA antigen can be studied by “chro‐matography” on fixed nuclei followed by the ACIF test. The obvious advantages of this method over chromatography on DNA‐cellulose are its simplicity, the possibility of testing many samples in one experiment and, especially, the use of minimal amounts of material. Significant differences in elution patterns for EBNA were found when nuclei derived from different cell lines (Ramos, Raji, and P3HR‐1) were converted in vitro to EBNA‐positivity. EBNA is eluted from in vitro‐converted nuclei of EBV genome‐positive P3HR‐1 cells at an almost 0.1 M higher concentration of NaCl than is necessary for a similar degree of elution from nuclei of EBV genome‐negative Ramos cells.
Studies of effector cell, antibody, and target cell interactions in natural cell‐mediated cytotoxicity
Authors: Koide Yukio , Kwok Rose , Takasugi Mitsuo 
Published: February 2007

AbstractIgG antibodies bound to effector cells through Fc receptors were observed to determine the specificity of natural cell‐mediated cytotoxicity (NCMC) against cultured target cells. When effector lymphocytes were isolated from the peripheral blood of most individuals, they already possessed natural antibodies specific for antigens on cultured cells. Since they lacked IgG antibodies specific for antigens on sheep red blood cell (SRBC) targets, natural cytotoxicity against SRBC was almost non‐existent. Effector cells incubated in IgG anti‐SRBC became specifically cytotoxic to SRBC. In the process, NCMC and antibody‐dependent cell‐mediated cytotoxicity was diminished, indicating that arming with anti‐SRBC replaced natural antibodies and occupied Fc receptors on effector cells. Thus, treating effector cells with serum may result in increased or decreased cytotoxicity depending upon the specificity of antibodies within the serum. This type of modulation of NCMC occurs at the interaction between antibody Fc and Fc receptors and can explain blocking and unblocking.
Effect of ricin and abrin on survival of L1210 leukemic mice and on leukemic and normal bone‐marrow cells
Authors: Fodstad øystein , Pihl Alexander 
Published: February 2007

AbstractThe effect of ricin and abrin on the survival of mice treated with L1210 leukemic cells intraperitoneally or intravenously was studied. In mice given 1 × 105 L1210 leukemia cells intraperitoneally a single dose of ricin (2.1 μg/kg) intraperitoneally gave the best results, an increased life span (ILS) of 59%. Abrin also increased the life span of such animals although to a lesser extent. The effect of ricin was superior to that of 5‐fluorouracil, but inferior to that of adriamycin, which gave a maximum ILS of 280%. In mice given L1210 cells intravenously no increase in life span was obtained with ricin, abrin or adriamycin, whereas 5‐fluorouracil gave an ILS of 40–50%. In spleen colony assays the differential effect of ricin and abrin on the proliferative capacity of normal hematopoietic and leukemic colony‐forming cells in bone marrow was studied. The differential effect of ricin was as good as that of adriamycin and considerably better than that of 5‐fluorouracil. Abrin had a much smaller effect than ricin on both normal and leukemic cells. The effect of abrin on the leukemic cells was too small to be of therapeutic value. The results warrant exploration of the use of ricin in the treatment of human leukemia.
Cytotoxic activity of guinea‐pig lymph‐node cells stimulated in vitro
Authors: Altman Amnon , Rapp Herbert J. 
Published: February 2007

AbstractGuinea‐pig lymph‐node cells (LNC) cultured for 5 days in medium containing fetal calf serum (FCS) were cytotoxic to various target cells. LNC cultured in medium supplemented with fresh, autologous guinea‐pig serum (GPS) instead of FCS were not detectably cytotoxic unless agents that stimulate lymphocyte proliferation were added to the culture medium. The stimulating agents we studied were 2‐mercaptoethanol (2‐ME), syngeneic tumor cells, allogeneic peritoneal exudate cells (PEC) and the T‐cell mitogens concanavalin A (Con A) and phytohemagglutinin (PHA). LNC cultured in the presence of these agents were cytotoxic to normal syngeneic fibroblasts and to syngeneic, allogeneic or xenogeneic tumor cells but not to PHA‐induced lymphoblasts. Potentiation of cytotoxicity in vitro was accompanied by a marked proliferation of the cultured LNC; the combination of several stimulatory agents had an additive effect on the generation of cytotoxicity in culture.
Enhancement of thermal killing by polyamines. I. Survival of chinese hamster cells
Authors: Ben‐Hur E. , Prager A. , Riklis E. 
Published: February 2007

AbstractExposure of Chinese hamster cells to polyamines at an elevated temperature (42°C) results in synergistic cell killing. The effectiveness of polyamines in potentiating thermal killing decreases in the following order: spermine>spermidine> cadaverine>putrescine. The magnitude of the synergism increases with exposure time. The survival curves, when plotted as a function of polyamine concentration, display a shoulder during 1 h exposure at 42°C, followed by exponential cell killing. Longer exposure times eliminate the shoulder and result in steeper slopes of the survival curves. The effect is maximal when exposure to polyamines and heat is simultaneous. Separation in time between the two treatments causes a rapid disappearance of the synergism. The order of application is of only minor importance in this regard. The results suggest that the intracellular level of spermine may be a major factor in determining heat sensitivity of Chinese hamster cells.
Cancer and „cancer related”︁ colorectal lesions in São Paulo, Brazil
Authors: Marigo Carlos , Correa Pelayo , Haenszel William 
Published: February 2007

AbstractA series of 832 necropsy specimens were studied grossly with a magnifying lens and all lesions identified were studied microscopically. The age and sex‐specific prevalence of adenomatous and hyperplastic polyps is reported and results are compared with those of other populations. A correlation was made between polyps and cancer of the colon and rectum (407 cases). The data suggest that São Paulo is a community in a transitional stage between intermediate and high risk of cancer of the colon. The epidemiologic characteristics of lower rectum cancer are peculiar to some populations and appear unrelated to colon cancer. The black population of São Paulo has a higher prevalence than that reported for African negroes. The data also implicate adenomatous polyps, diverticulosis and hemorrhoids as being probably related diseases.
Somatic cell hybrids between human lymphoma cell lines. V. IdUrd inducibility and P3HR‐1 superinfectability of Daudi/HeLa (DAD) and Daudi/P3HR‐1 (DIP‐1) cell lines
Authors: Moar M. H. , Ber R. , Klein G. , Westman A. , Eriksson I. 
Published: February 2007

AbstractWe have studied two types of somatic cell hybrid with regard to expression of the Epstein‐Barr virus (EBV) cycle and its regulation. The first, DIP‐1, a hybrid formed between two human lymphoma EBV producers (Daudi and P3HR‐1), contained EBV DNA, expressed the virus‐determined nuclear antigen (EBNA), and was a producer of the EBV‐associated antigens EA (early antigen) and VCA (viral capsid antigen). The second, DAD, a hybrid series of clones formed between Daudi and a HeLa cell derivative (D98), differed with regard to the expression of EBNA, EA, VCA and the content of EBV DNA. EA was regularly induced in the EBV DNA‐containing hybrids following treatment with iododeoxyuridine (IdUrd). This induction was greater in lines spontaneously expressing EA. In two hybrids, DIP‐1 and DAD10, VCA and virus DNA synthesis were also induced in the presence of IdUrd, the latter being detected by in situ hybridization with P3HR‐1 EBV complementary RNA. Finally, while DIP‐1 was superinfectable by the P3HR‐1 EBV strain, the DAD series of hybrids were refractory to P3HR‐1 superinfection and lacked EBV receptors.
Malignant lymphoma in four of five siblings
Authors: Nagel G. A. , Nagel‐Studer E. , Seiler W. , Hofer H. O. 
Published: February 2007

AbstractIn one family four out of five siblings were affected with malignant lymphoma and HD has been diagnosed in two other relatives. HLA‐haplotypes were identical for the three diseased siblings who were so studied, whereas for the unaffected one they were different.