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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thirty cases of malignant lymphoma, undifferentiated, Burkitt's type are reviewed. An older median age and a predominance of presentation in abdominal and pelvic sites rather than in the jaw distinguishes this series of American patients from those reported from endemic regions in Africa. Bone marrow involvement invariably consisted of massive infiltration recognizable in smear, clot and biopsy preparations. Involvement of the central nervous system or bone marrow was always associated with short survival. In all eight long-term survivors lymphoma was apparently confined to a single site at presentation. At autopsy, the most consistent finding was widespread multiorgan involvement without predilection for lymphoreticular structures. The histologic appearance of the tumor changed after chemotherapy, varying from diffuse necrosis within 48 hours of initial therapy to extreme pleomorphism of tumor cells after 9 months of therapy. In one patient, there was almost complete absence of lymphoma at autopsy in an organ site shown clinically to have been extensively involved by tumor prior to treatment. The diagnostic and therapeutic implications of these findings are discussed.
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PMID:American Burkitt's lymphoma: a clinicopathologic study of 30 cases. II. Pathologic correlations. 16 81

Herpesvirus saimiri (HVS) induced persistent, clinically inapparent infections of long-term duration in capuchin monkeys (Cebus albifrons). The infections were characterized by development of antibody to HVS-associated antigens and recovery of low levels of virus-genome-carrying lymphocytes in the peripheral blood. Peripheral lymphocyte counts remained in low-normal to normal ranges and no physical signs of lymphoma were evident. Prednisolone treatment caused immunosuppression in one monkey; this was accompanied by a progressive loss of humoral antibody to HVS-associated antigens, but neoplastic disease did not develop.
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PMID:Infection of capuchin monkeys (Cebus albifrons) with Herpesvirus saimiri. 16 64

The effect of Herpesvirus saimiri (HVS) infection on the response of owl monkey lymphocytes to general mitogens was examined during the development of neoplastic disease. The reactivity of the lymphocytes was then correlated with the clinical condition of the infected monkeys and the content of virus rescued from the peripheral blood lymphocytes (PBL). Eight monkeys developed lymphoma which, in six monkeys, was accompanied by lymphocytic leukemia. All animals that died of HVS-induced neoplasia consistently showed a lack of mitogenic response to phytohemagglutinin and concanavalin A. The response to pokeweed mitogen, while always reduced, was generally less markedly affected than the response to the other two mitogens. Lymphocytes from five of the leukemic animals demonstrated an elevated level of spontaneous DNA synthesis in culture late in the disease. This increased spontaneous DNA synthesis tended to correlate with the rescue of HVS from the PBL as demonstrated by the infective center assay. Although mitogenic hyporesponsiveness corresponded with HVS rescue from PBL in six of nine monkeys, the impairment of normal lymphocyte responsiveness sometimes preceded virus recovery.
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PMID:Depression in lymphocyte response to general mitogens by owl monkeys infected with Herpesvirus saimiri. 16 65

Twenty-two of 39 rabbits inoculated with Herpesvirus saimiri developed malignant lymphoma and either died or were killed between 17 and 165 days after inoculation. No clinical signs were present in animals developing the disease before 46 days, but all other rabbits had a severe conjunctivitis, nasal discharge, and dyspnea resulting from a lymphocytic invasion of the ocular and nasal tissues. Four rabbits developed terminal leukemia. Pathologically, the disease resembled H. saimiri malignant lymphoma in nonhuman primates; there was extensive diffuse infiltration of most organs and tissues with either a lymphocytic or lymphoblastic infiltrate. Tumor nodules or masses seen in some forms of malignant lymphoma were not present. In contrast to nonhuman primates, all affected rabbits showed invasion of the skin of the nose and eyelids, conjunctiva, iris, ciliary body, and choroid. In 3 rabbits there was slight infiltration into the brain, not noted in nonhuman primates. The susceptibility of rabbits extended the host range of H. saimiri beyond the order Primates.
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PMID:Clinicopathologic characterization of Herpesvirus saimiri malignant lymphoma in New Zealand white rabbits. 16 91

A 3-year-old female Siamese cat was admitted to a local animal hospital with a history of recent extreme lethargy and anorexia. A hemorrhagic tumor was removed from an area of oral buccal skin and diagnosed histopathologically as lymphosarcoma. Rapid physical deterioration occurred, and the cat became moribund 2 weeks after surgical operation. Necropsy revealed at least 200 spherical hemorrhagic neoplastic nodules attached to the omentum, mesentery, and peritoneum. Examination of histopathologic sections confirmed the striking characteristics of an extremely vascular and highly invasive malignant lymphoma, which was designated feline tumor No. 01 (FeT-01). There was no evidence of peripheral blood leukemia. Electron microscopic examination of tumor tissue revealed numerous viral particles having characteristics common to both feline leukemia virus (FeLV) and feline syncytium-forming virus (FeSFV). Primary cells and cultures propagated from tumor tissue were found to be negative or weakly positive for group-specific (gs) antigen by radioimmunoassay but strongly positive when assayed by indirect immunofluorescence. Co-cultivation of cells from tumor tissue, with normal prescreened feline embryo cells, revealed the presence of numerous FeSFV-like viral particles in the absence of C-type virus. A FeSFV was isolated from these passaged cells, with characteristics similar to FeSFV isolates previously described in the literature. The apparent presence of FeSFV in lymphosarcomatous tissue and the apparent absence of FeLV C-type particles in passaged cells indicate the need to make a more intensive study of the FeSFV group of viruses and the possible etiologic relationship to feline malignancies.
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PMID:An unusual case of feline leukemia and an associated syncytium-forming virus. 16 23

Except for tumors clearly producing immunoglobulin (e.g. plasma-cytoma), the different classes of malignant lymphomas do not correlate with a constant surface immunoglobulin pattern. Beside a prevailing IgM-surface type in a high number of different lymphoma classes even T-like or O-cells occur in most tumor types provided they are studied in a sufficient number. The possibility of dedifferentiation of immunologic cell qualities has to be envisaged. In this context intracellular lambda-chain crystals occurring in chronic lymphocytic leukaemia may provide a morphological hallmark of anaplastic deterioration of immunoglobulin synthesis. - The ambiguous significance of PAS-positive inclusions and virus-like microtubular complexes in lymphoma cells is discussed. - In conclusion the recent discovery of hairy cell leukaemia provides a good example of the value of nomenclatures based on empiricism rather than on short-lived theories.
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PMID:Morphological classification of malignant lymphomas: ultrastructural, cytochemical and immunological results. 16 21

Tetraparental AKR-CBA/H-T6 chimeras were primarily derived and investigated to determine whether factors associated with the tumor resistance of the CBA/H-T6 could overcome the innate lymphoma susceptibility of the AKR. Evidence has since shown that, on comparison with the AKR, lymphomas were not only delayed but were also less common in a group of 18 early embryo aggregation derived AKR-CBA/H-T6 tetraparental chimeras. Evidence here has shown other clear differences between the AKR and AKR-CBA/H-T6 chimeras. Whereas murine group-specific murine leukemia viral antigens were detected in the sera in both situations, immunoabsorption studies showed that, in the AKR, the antigens exist complexed to the corresponding antibodies. The situation in the chimeras was in complete contrast, since here antigens exist as a "free" form. This in turn has led us to suggest that the advantage in respect to tumor immunity in the AKR-CBA/H-T6 chimeras is due to the tolerance to oncogenic virus being maintained. In this situation and in contrast to the AKR, in the absence of "masking" antibody-viral antigenic complexes, "normal" tumor immunity can be effected. It has to be assumed that tolerance to the oncogenic Gross virus in the AKR-CBA/H-T6 chimeras reflects the influence of the CBA component. How this has possibly been achieved is discussed.
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PMID:Failure to detect anti-group-specific murine leukemia virus activity in tetraparental AKR-CBA chimeras. 16 64

Hamster and rabbit antibodies against antigens on the surface of simian virus 40 (SV40)-transformed hamster sarcoma or lymphoma cells were purified by immunoadsorption on SV40-transformed cells and conjugated to diphtheria toxin with glutaraldehyde. Treatment with a single dose of antibody-toxin conjugate partially protected hamsters concurrently challenged with 10(3) SV40-transformed sarcoma cells, as evidenced by a reduction in tumor incidence, an increase in tumor latency, and a prolongation of the life-spans of hamsters that developed tumors. Treatment of established sarcomas was ineffective, but repeated treatment with the conjugates induced complete regressions in 20-56% of hamsters bearing established transplants in the SV40-induced lymphoma.
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PMID:Antitumor effects of antibody-diphtheria toxin conjugates. II. Immunotherapy with conjugates directed against tumor antigens induced by simian virus 40. 16 78

Humoral antibodies can be induced in cotton topped (CT) marmosets with killed Herpesvirus saimiri (HVS) vaccines. The serum antibodies delayed, but did not prevent, malignant lymphoma in actively and passively immunized monkeys after inoculation with 10(3.8)TCID50 of cell-free HVS. Experiments are in progress to determine whether the vaccines are able to protect against smaller challenge dosages of HVS. The immunized monkeys were not resistant against transplantation of tumor cells. Infection with Epstein-Barr virus (EBV) and Marek's disease virus (MDV) did not protect against the tumors caused by superinfection with HVS. Attenuation of HVS was not achieved by passaging the HVS genome through different monkey species.
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PMID:Experiments to vaccinate marmoset monkeys against malignant lymphoma. 16 14

The oncogenic potential of Epstein-Barr virus (EBV) was investigated in cottontop marmosets. Neoplasia resembling human malignant lymphomas, reticulum cell sarcoma type, occurred following inoculation of materials containing EBV. One of 4 monkeys that received autologous cells transformed in vitro by EBV developed lymphoma in mesenteric lymph nodes seven and one-half months after inoculation. Three of 4 marmosets inoculated with cell-free EBV developed lymphoma. The latent period for given with EBV accelerated the course of disease. Nevertheless malignant lymphoma occurred in an animal given only cell-free virus. Six of 8 marmosets inoculated with EBV demonstrated antibodies to the virus. Four marmosets not exposed to the virus, of which 2 received immunosuppressive drugs, have not developed tumors, nor EBV antibodies. EBV antigen detectable by immunofluorescences has been found in 2% of cells shed from one tumor maintained in organ culture. These results imply that EBV is capable of inducing malignant lymphoma in at least one primate species. Additional experimental evidence is required, however, before its oncogenic capacity in this host can be accepted without reservation.
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PMID:EB virus: malignant lymphoma in cottontop marmosets following inoculation and recovery of the virus from cells of an experimental tumor maintained in organ culture. 16 16


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