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Results for “LEUKEMIA, EXPERIMENTAL”

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At least 199 records · Page 11Linked to original sources
PubMed2003

Mixed chimerism of bone marrow vessels (endothelial cells, myofibroblasts) following allogeneic transplantation for chronic myelogenous leukemia.

Experimental findings support the hypothesis that within the functional network of the bone marrow (BM) microenvironment the endothelial cells (ECs) exert a pivotal role as gatekeepers by controlling the trafficking and homing of progenitor cells. However, little information is available concerning the origin of ECs after allogeneic bone marrow transplantation (BMT) in CML. To determine the extent of mixed chimerism (MCh) a simultaneous immunohistochemical and fluorescence in-situ hybridization (FISH) study was performed on BM biopsies derived from patients following sex-mismatched BMT with full unmanipulated BM. ECs were identified by their staining with CD34 and the myofibroblasts (MFs) of large vessels were labeled by an antibody against alpha-smooth muscle actin. For sex-typing and demonstration of the bcr/abl fusion product appropriate commercially available probes and detection systems were applied. Contrasting a total congruence of labeling in control samples five patients showed donor type ECs in the early posttransplant period in about 20%. In the remaining four patients the amount of donor type ECs increased slightly after the third month up to 30%. A total of 26 MFs could be identified lining large capillaries and arterioles that exclusively revealed a host origin. Following successful engraftment only very few of the persistent host-derived ECs also displayed the bcr/abl gene. In five patients, a conversion of MCh from donor to host type ECs was recognizable during the evolution of leukemic relapse. This finding was accompanied by a bcr/abl rearrangement of about 10% of these cells. In conclusion, following myelo-ablative therapy, a survival of a considerable number of ECs and MFs of the vessel walls has been found implying persistence of host-derived vascular structures of the BM stroma. However, in only a small proportion bcr/abl+ ECs and thus minimal residual disease was detectable. Evolution of leukemic relapse was characterized by conversion of MCh with almost total loss of donor type ECs and increase in number of bcr/abl+ ECs.

Adult↗
PubMed1979

BLV-LB virus-specific sequences in cattle with spontaneous and experimentally induced leukemia.

Poly(A)-containing RNAs were extracted directly from the culture fluid of BLV-producing continuous and short-term lymphocyte cultures. The abovesaid poly(A)-RNAs were used as a template to synthesize complementary [3H]DNA (BLV cDNA). BLV cDNA possessed a high degree of homology to poly(A)-RNA isolated directly from the blood plasma of a leukemic animal. In contrast of leukemic cattle BLV-related sequences in white blood cells of normal animals were absent. Leukemic cells of cattle with both, spontaneous and experimentally induced leukemia contained bovine leukemia virus sequences in their genomes.

Animals↗
PubMedDate not supplied

NGF overexpression and distribution in cortical thymic epithelial cells of mice with experimentally-induced leukemia.

BACKGROUND: Thymic epithelial cells often form lymphoid-epithelial cell (LEC) complexes, thought to contribute both to normal T-cell differentiation and to leukemogenesis. The distribution of the nerve growth factor (NGF) and NGF immunoreactivity modulation of complex-forming thymus epithelial cells were studied in mice with experimental acute L1210 leukemia. MATERIALS AND METHODS: Light and electron microscopic methods and cell separation techniques were applied. RESULTS: Immunoperoxidase and immunogold labelling showed subcapsular and subseptal overexpression of NGF by epithelial cells in leukemic thymus. NGF immunopositive epithelial cells were closely associated with lymphoid cells. The increased immunoreactivity of epithelial cells correlated with LEC complex formation, including thymic nurse cell-like structures and rosettes in the external cortex. CONCLUSION: These results provide new structural and immunocytochemical evidence for intimate contact between NGF-producing epithelial cells and lymphoid cells and suggest that NGF immunoreactive LEC complexes are involved in thymic microenvironmental reorganization during leukemogenesis.

Animals↗
PubMed1991

Disease progression and viral genome variants in experimental feline leukemia virus-induced immunodeficiency syndrome.

A fatal immunodeficiency syndrome with clinical and pathologic features similar to human AIDS is inducible in cats by experimental inoculation with a specific strain of feline leukemia virus (FeLV) called FeLV-FAIDS. The course of the feline disease is characterized by an age-dependent prodromal period during which a non-disease-specific, common form of proviral DNA is detected in bone marrow. Preceding clinical onset of immunodeficiency is production of high levels of specific, pathogenic variant genomes, primarily as unintegrated viral DNA, in bone marrow. Acute immunodeficiency syndrome (survival period approximately 3 months) is associated with a short prodromal period and appearance of a characteristic variant genome (variant A) that persists at high copy number as integrated and full-length unintegrated viral DNA in bone marrow. Chronic immunodeficiency syndrome (survival greater than 1 year) is marked by a longer prodromal period, a more gradual onset of severe clinical immunosuppression, and a predominance of other variant genomes that often contain substantial internal deletions. In both forms of the disease, tissue-specific replication of certain variant viruses is noted in the bone marrow, intestine, and lymph nodes. Evidence from in vitro and in vivo virus transmission studies indicates that the appearance of FeLV-FAIDS variant viruses reflects differential replication of viral genomes pre-existing in the inoculum rather than rapid de novo evolution of new variants within each animal. These results demonstrate that retrovirus-induced immunodeficiency disease in cats can be associated with and prefigured by the amplified replication of specific viral variants in target tissues.

Animals↗
PubMed1976

Electrocardiographic and pathological studies of the heart in experimental guinea pig leukemia.

Electrocardiographic tracings were performed on 26 strain 2 guinea pigs in which leukemia was induced by inoculation of L2C leukemic cells. All inoculated animals developed leukemia. In terminal phases of this disease significant electrocardiographic changes were observed in 20 of the 26 animals; in 5 animals the electrocardiograms were normal and in 1 guinea pig the changes were borderline. The most significant changes consisted of the onset of a Q-wave or a T-wave inversion or both. Pathological examination of the heart removed in the terminal phase of the disease revealed infiltration of the endocardium and epicardium and in the capillaries of the myocardium. Such areas of infiltration, when viewed with the electron microscope, revealed the presence of leukemic cells within the lumen of capillaries and in areas immediately surrounding the capillaries. Infiltration of myocardial fibers was not observed. The electrocardiographic changes observed in guinea pig leukemia may be related to the leukemic infiltration of myocardial capillaries and the resulting anoxia.

Animals↗
PubMed1989

[Autoimmune reactions against interleukin-2 receptors in patients with blood system diseases and in experimental Rauscher retrovirus leukemia].

Apart from autoimmune reactions, antibodies to IL-2 receptors were identified in blood sera of linear mice during leukemogenesis. It is indicated that in the course of leukemia establishment, there can be demonstrated antibodies capable of blocking IL-2 receptors on the membrane of activated T lymphocytes and inhibiting IL-2-dependent proliferation of T cells. The blood sera of patients suffering from chronic lymphoid leukemia, acute lymphoblastic leukemia, lymphocytomas, pure red-cell aplasia, and aplastic anemia showed antibodies against IL-2 receptors. Out of the total number of 52 patients, 23 demonstrated those antibodies. The data obtained should be taken into account in the patients' management using IL-2.

Adult↗
PubMed1987

Effects of treatment with cobra venom factor on experimentally induced feline leukemia.

Five- to six-month-old specific-pathogen-free cats were exposed to cobra venom factor (CVF) alone (4 cats), Rickard feline leukemia virus (FeLV; 9 cats), or CVF and FeLV (6 cats). Host-virus relationships were evaluated by monitoring the development of viremia, production of antibody against feline oncornavirus-associated cell membrane antigen, and amount of circulating immune complexes (CIC). Exposure to CVF induced complement depletion, which lasted 8 to 15 days. However, complement depletion did not promote the development of persistent viremia nor alter the production of antibody to feline oncornavirus-associated cell membrane antigen or CIC. Results indicated that the complement system did not protect cats during their initial exposure to FeLV and that an intact complement system was not necessary for the development of antibody against feline oncornavirus-associated antigen or for the formation of CIC.

Animals↗
PubMed1995

Regression of experimental human leukemias and solid tumors induced by Epstein-Barr virus-immortalized B cells.

We previously have reported on an experimental athymic mouse model in which regression of human Burkitt's lymphoma is induced by either coinjection with or intratumor inoculation of Epstein-Barr virus (EBV)-immortalized human B cells. In the current study, we were interested in determining whether the powerful antitumor effects of EBV-immortalized B cells could be effective against a variety of human tumors grown in athymic mice, including acute lymphocytic leukemia, malignant melanoma, acute promyelocytic leukemia, neuroblastoma, lung carcinoma, colon adenocarcinoma, Wilms tumor, Hodgkin's lymphoma, rhabdomyosarcoma and breast adenocarcinoma. We report here the results of experiments in nude mice that demonstrated the potent antitumor effect of EBV-immortalized B cells against human tumors derived from a variety of different tissues.

Animals↗
PubMed1982

[Morphogenesis of neuroleukemia].

A comparative study of neuroleukemia in children with acute leukemia and in mice with experimental leukemia was carried out. Spontaneous leukemia in AKR mice and transplantation leukemia (LIO-I, La, P388, L-5178Y) were shown to be adequate models for investigations on the pathogenesis of neuroleukemia. The initial morphological manifestations of neuroleukemia consisted in infiltration of dura mater of the brain and epidural space, particularly of the lumbar region of the spine. The leukemic cell infiltrates originating from the bone marrow spread along the walls of vascular anastomoses between the venous system of the skull and vertebrae on the one hand, and dura mater of the brain and epidural space of the spinal cord, on the other.

Acute Disease↗