Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Cas-Br-E strain of murine leukemia virus is a neurovirulent retrovirus that induces progressive noninflammatory degeneration of the central nervous system (CNS). The molecular clone pNE-8 retains pathogenic properties of Cas-Br-E. The neurotropic determinants are known; however, the mechanism of neuropathogenesis is unknown. We examined the temporal development of disease after infection of SWR/J mice with pNE-8 virus. Development of CNS lesions, cellular targets of viral replication, accumulation of ubiquitinated proteins and integrity of blood-brain barrier were determined in mice infected with pNE-8 virus; and compared with uninfected, sham-infected, and nonneuropathogenic virus-infected mice. During 24 weeks of pNE-8 infection, noninflammatory spongiform lesions developed initially in the lumbar spinal cord and progressed to involve the brainstem and deep cerebellar nuclei. Virions and viral antigens accumulated for 18 weeks postinfection and then declined. Major sites of viral infection outside the CNS were splenic megakaryocytes, and skeletal muscle. Cellular targets of viral replication in the CNS included neurons, oligodendrocytes, and capillary endothelium. No astrocytic infection was observed; however, a reactive gliosis marked the development of clinical symptoms and histopathology. Spongiform lesions began as swelling of perivascular astrocytic processes. Intramyelinic vacuoles with splitting of myelin at major dense lines were prominent around dystrophic axons at later time points. Dendritic processes showed vacuolization and local degeneration. Viral particles were most commonly observed in extracellular spaces and within rough endoplasmic reticulum of neurons, oligodendrocytes, and splenic megakaryocytes. Infected megakaryocytes and regions of spleen containing viral aggregates showed accumulation of ubiquitinated proteins. Areas of histopathology in the CNS showed accumulation of ubiquitinated proteins but unlike spleen, viral proteins were not highly ubiquitinated. Disruption of the blood brain barrier was only evident at late stages of infection. In conclusion, the neuropathogenic damage associated with pNE-8 infection appears to be tightly associated with direct viral infection of oligodendroglia and neurons.
 ...
PMID:Development of spongiform encephalopathy in retroviral infected mice. 131 97

Four classes of murine leukemia virus (MuLV) which display distinct cellular tropisms and bind to different retrovirus receptors to initiate virus infection have been described. In the present study, we describe a rapid, sensitive immunofluorescence assay useful for characterizing the initial binding of MuLV to cells. By using the rat monoclonal antibody 83A25 (L. H. Evans, R. P. Morrison, F. G. Malik, J. Portis, and W. J. Britt, J. Virol. 64:6176-6183, 1990), which recognizes an epitope of the envelope gp70 molecule common to the different classes of MuLV, it is possible to analyse the binding of ecotropic, amphotropic, or xenotropic MuLV by using only a single combination of primary and secondary antibodies. The MuLV binding detected by this assay is envelope receptor specific and matches the susceptibility to infection determined for cells from a variety of species. The binding of amphotropic MuLV to NIH 3T3 cells was shown to be rapid, saturable, and temperature dependent. Chinese hamster ovary (CHO-K1) cells normally lack the ability to bind ecotropic virus and are not infectible by ecotropic vectors. Expression of the cloned ecotropic retrovirus receptor gene (Rec) in CHO-K1 cells confers high levels of ecotropic virus-specific binding and confers susceptibility to infection. Characterization of MuLV binding to primary cells may provide insight into the infectibility of cells by retroviruses and aid in the selection of appropriate vectors for gene transfer experiments.
 ...
PMID:Detection of receptor-specific murine leukemia virus binding to cells by immunofluorescence analysis. 131 32

A molecular clone of wild mouse ecotropic retrovirus CasBrE (clone 15-1) causes a spongiform neurodegenerative disease with a long incubation period, greater than or equal to 6 months. This virus infects the central nervous system (CNS) at low levels. In contrast, a chimeric virus, FrCasE, containing env and 3' pol sequences of 15-1 in a Friend murine leukemia virus background, infects the CNS at high levels and causes a rapid neurodegenerative disease with an incubation period of only 16 days. With both viruses, the induction of neurologic disease is dependent on inoculation during the perinatal period. Since the length of the incubation period of this disease appears to be a function of the relative level of CNS infection, we have attempted to identify the viral and host factors which determine the relative level of virus infection of the CNS. It was previously shown that the CNS is susceptible to infection only during the perinatal period (M. Czub, S. Czub, F. J. McAtee, and J. L. Portis, J. Virol. 65:2539-2544, 1991). Here we have found that the susceptibility of the CNS wanes progressively or gradually as a function of the age of the host, this age-dependent resistance being complete by 12 to 14 days of age. Utilizing a group of chimeric viruses, we found that the relative level of CNS infection achieved after inoculation of mice at 1 day of age was a function of the kinetics of virus replication and spread in peripheral organs. Viruses which reached peak viremia titers early (5 to 7 days of age) infected the CNS at high levels, and viruses which reached peak titers later infected the CNS at lower levels. Among the group of viruses examined in the current study, the kinetics of peripheral virus replication and spread appeared to be influenced primarily by sequences within the R-U5-5' leader region of the viral genome. These results suggested that the relative level of CNS infection was determined very early in life and appeared to be a function of a dynamic balance between the kinetics of virus replication in the periphery and a progressively developing restriction of virus replication in the CNS.
 ...
PMID:Murine retrovirus-induced spongiform encephalomyelopathy: host and viral factors which determine the length of the incubation period. 131 49

We reviewed the records of all patients with a diagnosis of malignancy who were treated at our center and who had not had chemotherapy for at least 18 months, to assess the prevalence of chronic hepatitis B surface antigen (HBsAg)-negative hepatitis, to assess the prevalence of a marker of hepatitis C virus infection, and to determine the severity of chronic liver disease. Of 557 eligible patients, 38 (6.8%) had chronic HBsAg-negative hepatitis. Of these 38 patients, 20 (52.6%) had a marker of hepatitis C virus infection. The prevalence of chronic HBsAg-negative hepatitis was higher in patients previously treated for leukemia than in patients treated for another malignancy (11.8% vs 4.6%; p = 0.004). The liver biopsy revealed chronic active hepatitis or cirrhosis or both in 8 (28%) of 28 patients with clinical chronic HBsAg-negative hepatitis. Four patients without hepatitis C virus infection who underwent liver biopsy had hepatitis B virus antigen in the liver, confirmed by immunohistochemistry studies. One patient uninfected with hepatitis C virus had hemochromatosis. We conclude that infection with hepatitis C virus was the major cause of chronic HBsAg-negative hepatitis in pediatric patients previously treated for malignancy; the cause remained unidentified in 30% of the patients.
 ...
PMID:Chronic hepatitis B surface antigen-negative hepatitis after treatment of malignancy. 132 Jun 73

Mice infected with LP-BM5 murine leukemia viruses develop a syndrome, termed mouse AIDS (MAIDS), characterized by increasingly severe immunodeficiency and progressive lymphoproliferation. Virus-infected mice were examined for the ability to resist acute infection and to control chronic infection with the protozoan Toxoplasma gondii, a major opportunistic pathogen of individuals infected with human immunodeficiency virus. Mice infected with the retroviruses for 2 or 4 weeks responded normally to challenge with the parasite, but mice inoculated with the protozoan 8 or 12 weeks after viral infection died with acute disease due to T. gondii. Increased sensitivity to acute infection was associated with a reduced ability to produce gamma interferon (IFN-gamma) and with established changes in CD4+ T-cell function. Mice latently infected with T. gondii and then inoculated with the retrovirus mixture were found to reactivate the parasite infection, with 30 to 40% of dually infected animals dying between 5 and 16 weeks after viral infection. Reactivation was associated with reduced proliferation and impaired production of IFN-gamma in response to stimulation with soluble T. gondii antigens or to concanavalin A. Continuing resistance to lethal reactivation in the remaining mice was shown to require CD8+ T cells and expression of IFN-gamma. In addition, it was found that chronic infection with T. gondii altered the course of MAIDS by inhibiting the progression of splenomegaly and immunodeficiency and reducing the expression of both the helper and etiologic defective viruses. These results support previous studies which indicate that infection with T. gondii is controlled by synergistic interactions between CD4+ and CD8+ T cells, the functions of which are progressively impaired during the course of MAIDS.
 ...
PMID:Opportunistic infections and retrovirus-induced immunodeficiency: studies of acute and chronic infections with Toxoplasma gondii in mice infected with LP-BM5 murine leukemia viruses. 132 58

The pathogenetic potential and the true extent of human T leukemia/lymphotropic virus type I (HTLV-I) and type II (HTLV-II) infection are unknown. To find out more about HTLV-I/II seroepidemiology and the risks of iatrogenic transmission, we performed a serological study, screening 4086 healthy blood donors. A surprisingly high percentage of serum reactivity to HTLV-I/II antigens was observed by commercial ELISA (2.08%) and immunoblotting (IB) (0.85%) analysis, although none of the samples satisfied the (IB) criteria for positivity based on detection of gag protein p24 and at least one env gene product, either gp46 or gp61/68. To clarify these inconclusive results, we performed polymerase chain reaction (PCR) analysis for HTLV-I and HTLV-II provirus detection in peripheral blood lymphocytes, obtained from individuals with an apparent pattern of seropositivity. The data obtained by PCR failed to reveal evidence of HTLV-I/II provirus integration in peripheral blood cells, ruling out the possibility of a viral infection in these cases, and pinpointing the limitations of both serological methods used. Our observations suggest that serological assays alone are not a reliable tool for blood donor screening of HTLV-I/II infection and raise the important question of interpreting inconclusive results.
 ...
PMID:Absence of HTLV-I/II infection in blood donors with positive and inconclusive HTLV-I/II serology. 133 13

It is difficult to evaluate the protective efficacy of species-specific viruses of humans and expensive companion animals where there is no non-human animal model. This study describes an in vivo model system which allows simultaneous operation of humoral, cell-mediated, interferon-like or other unidentified immunological defence mechanisms. There was evidence of in vivo inactivation of both enveloped and unenveloped DNA and RNA viruses including retrovirus mouse sarcoma virus/mouse leukaemia virus as evaluated by assay of the enzyme reverse transcriptase. This model will allow examination of vaccine efficacy in immunocompetent host animals while avoiding morbidity and/or mortality from virus infection in these animals.
 ...
PMID:In vivo model for evaluation of species-specific virus vaccines. 133 88

Natural or experimental feline immunodeficiency virus (FIV) infection in cats is often associated with hematologic abnormalities which are similar to those observed in human immunodeficiency virus (HIV) infected patients. To determine if cells in bone marrow are infected with FIV and whether severity of hematopoietic disorder is correlated with the level of viral infection, bone marrow tissues from ten experimentally and two naturally FIV infected cats were examined by in situ hybridization for presence of FIV RNA. Seven of the 12 FIV infected cats were also naturally or experimentally coinfected with feline leukemia virus (FeLV). FIV RNA was detected mainly in megakaryocytes and unidentified mononuclear cells in the bone marrow of cats that were sick and had marrow hypercellularity and immaturity. These included all cats in the acute phase of FIV infection and two of seven long term FIV infected cats. One long term FIV infected cat with lymphosarcoma was also positive for FIV RNA in bone marrow cells. The other four long term FIV infected cats were relatively healthy, with normal bone marrow morphology, and were negative for FIV infected cells. Bone marrow from three non-infected and two cats infected with FeLV alone were also negative for FIV RNA by in situ hybridization. We concluded that megakaryocytes and mononuclear cells were targets of the viral infection and that the presence of FIV RNA in cells of the bone marrow correlated with marrow hypercellularity and immaturity, and severity of illness.
 ...
PMID:Detection of feline immunodeficiency virus infection in bone marrow of cats. 133 1

Total body x-irradiation has been utilized in the treatment of several human diseases, including leukemia, where it is followed by bone marrow transplantation, and in some autoimmune disorders. Recently, it was reported that total body irradiation appeared useful in the treatment of Friend leukemia virus infection in mice. In this report, the effect of x-irradiation on the replication of human immunodeficiency virus (HIV) in vitro in CD4+ cells was examined. MT-4 cells and HIV strain human T cell lymphotropic virus Type IIIB were used to conduct this study. Infected MT-4 cells were irradiated at the time of infection or following infection with x-ray doses of 25-300 cGy. Doses of 50, 150, and 300 cGy enhanced HIV replication by 1.6-, 2-, and 4.8-fold, respectively. Irradiating the cells prior to infection also resulted in similar enhancement of HIV replication. This phenomenon was also observed with wild-type HIV isolates grown in peripheral blood mononuclear and in HIV chronically infected cells. In addition, the enhancement was associated with a radiation-induced increase in intracellular levels of cAMP. The use of the cAMP-dependent protein kinase A inhibitor, H-8, inhibited HIV replication by 65%. These data suggest that in vitro exposure to low doses of x-ray enhances HIV replication partially via a cAMP-dependent pathway.
 ...
PMID:X-irradiation enhances in vitro human immunodeficiency virus replication correlation with cellular levels of cAMP. 135 47

Thirty-two patients with leukemia or non-Hodgkin's lymphoma (NHL) who underwent high-dose chemotherapy without total body irradiation (TBI) and peripheral blood stem cell autografts (PBSCT) were evaluated for the occurrence of clinically manifested varicella-zoster virus infection (VZV). In a minimum follow-up of 3 mo, there were 14 cases with VZV; 12 patients were treated with intravenous acyclovir and 2 patients received additional intravenous VZV hyperimmune immunoglobulin preparations. History of previous varicella-zoster at some time before PBSCT was the only significant risk factor for the development of VZV. Furthermore, a significant association between VZV and higher disease-free survival rate after PBSCT was proved. Development of minor and reversible VZV is rather common event after high-dose chemotherapy without TBI and PBSCT. VZV appears to be one of the factors which reflects basic physiologic mechanism preventing relapse of leukemias or NHL after PBSCT.
 ...
PMID:[Varicella-zoster virus infection after peripheral blood stem cell autografts in children with leukemia or non-Hodgkin's lymphoma]. 135 69


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>