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)

Differential characterization of the "reticulum cell" in lymphoreticular neoplasms. Am J Clin Pathol. 64: 171-179, 1975. The term "reticulum cell" is confusing, having been applied to the cells involved in many hematopoietic neoplasms, such as reticulum-cell sarcoma, histiocytic medullary reticulosis, leukemic reticuloendotheliosis, and monocytic or histiocytic leukemias. In histologic sections, even the cells from poorly differentiated extramedullary lesions of chloroma or myeloblastic leukemia have been called "reticulum cells."A combined morphologic and cytochemical approach has been used to study "reticulum cells"in smears and tissue sections of neoplasms involving "histiocytes" or "reticulum cells."The cytochemical markers are: chloracetate esterase for neutrophilic granulocytes; nonspecific esterase and fluoride-resistant esterase for monocytes and histiocytes (phagocytes); tartrate-resistant acid phosphatase for the reticulum cells of leukemic reticuloendotheliosis; pyronin for the lymphatic reticulum cells (germinal center cells). The morphology of these cells is very well appreciated in smears, and the locations of these marked cells in tissue sections are easily recognized. The use of cytochemical and immunochemical methods and functional studies, in addition to simple morphology, may be useful in subclassification of lymphoreticular neoplasms.
 ...
PMID:Differential characterization of the "reticulum cell" in lymphoreticular neoplasms. 109 40

Eight cases of 'hairy' cell leukaemia (leukaemic reticuloendotheliosis) were evaluated by scanning electron microscopy. The surface of critical-point-dried 'hairy' cells was characterized by prominent and exaggerated broad-based, ruffled membranes and scattered small clusters of stub-like microvilli. The surface morphology resembled that of normal and leukaemic monocytes, but differed from that of normal and leukaemic lymphocytes. Some cells with features of both lymphocytes and monocytes were difficult to categorize; the overall impression of the surface architecture of most 'hairy' cells suggests, however, that they are related to the monocytic series. From the examination of these cases it is evident that scanning electron microscopy may be used as a means of distinguishing chronic lymphocytic leukaemia from 'hairy' cell leukaemia on the basis of surface ultrastructure.
 ...
PMID:'Hairy' cell leukaemia (leukaemic reticuloendotheliosis): a scanning electron microscopic study of eight cases. 119 57

In seven patients the diagnosis of hair cell leukaemia (leukaemic reticuloendotheliosis) was confirmed cytochemically and histologically. Splenectomy, in six patients, apparently favourably influenced the course. Isoenzyme 5 of the acid phosphatase was demonstrated in the hairy cells of all patients. Reaction of alpha-naphthylacetate esterase was moderately positive in the hairy cells. Phagocytosis of latex and India-ink particles was demonstrated especially in tartrate-resistant cells of one patient. In two patients eight permanently growing cell lines were demonstrated from leucocytes and defined cytochemically. Capacity for phagocytosis of hairy cells and positive reaction of alpha-naphthylacetate esterase in the hairy cells suggest properties of monocytes. But it is not possible definitively to classify the hairy cells among B-cells or monocytes.
 ...
PMID:[Hairy cell leukaemia. I. Clinical features, cytochemistry, phagocytosis, establishment of permanent growing cell lines (author's transl)]. 124 50

The reticuloendotheliosis viruses (REV) are a family of highly related retroviruses isolated from gallinaceous birds. On the basis of sequence comparison and overall genome organization, these viruses are more similar to the mammalian type C retroviruses than to the avian sarcoma/leukemia viruses. The envelope of a member of the REV family, spleen necrosis virus (SNV), is about 50% identical in amino acid sequence to the envelope of the type D simian retroviruses. Although SNV does not productively infect primate or murine cells, the receptor for SNV is present on a variety of human and murine cells. Moreover, interference assays show that the receptor for SNV is the same as the receptor for the type D simian retroviruses. We propose that adaptation of a mammalian type C virus to an avian host provided the REV progenitor.
 ...
PMID:Spleen necrosis virus, an avian immunosuppressive retrovirus, shares a receptor with the type D simian retroviruses. 131 15

The retroviral genome consists of two identical RNA molecules associated at their 5' ends by a stable structure called the dimer linkage structure. The dimer linkage structure, while maintaining the dimer state of the retroviral genome, might also be involved in packaging and reverse transcription, as well as recombination during proviral DNA synthesis. To study the dimer structure of the retroviral genome and the mechanism of dimerization, we analyzed features of the dimeric genome of reticuloendotheliosis virus (REV) type A and identified elements required for its dimerization. Here we report that the REV dimeric genome extracted from virions and infected cells, as well as that synthesized in vitro, is more resistant to heat denaturation than avian sarcoma and leukemia virus, murine leukemia virus, or human immunodeficiency virus type 1 dimeric RNA. The minimal domain required to form a stable REV RNA dimer in vitro was found to map between positions 268 and 452 (KpnI and SalI sites), thus corresponding to the E encapsidation sequence (J. E. Embretson and H. M. Temin, J. Virol. 61:2675-2683, 1987). In addition, both the 5' and 3' halves of E are necessary in cis for RNA dimerization and the extent of RNA dimerization is influenced by viral sequences flanking E. Rapid and efficient dimerization of REV RNA containing gag sequences in addition to the E sequences and annealing of replication primer tRNA(Pro) to the primer-binding site necessitate the nucleocapsid protein.
 ...
PMID:Analytical study of avian reticuloendotheliosis virus dimeric RNA generated in vivo and in vitro. 133 19

Promiscuous transcriptional activity of the reticuloendotheliosis virus (REV) long terminal repeat (LTR) was detected in transient expression assays using LTR-chloramphenicol acetyltransferase-encoding gene chimeras, and cells of diverse species and tissue type; levels of expression from two different REV LTRs correlate with reports of pathogenicity of the respective viruses in vivo. REVs do not encode a transactivator targeted to the viral LTR, and cells infected with Marek's disease virus, a herpesvirus with an overlapping host range, do not express factors that preferentially enhance expression from REV or avian sarcoma/leukemia virus LTRs. REV LTRs work efficiently in human lymphoid cells, and are viable alternatives to promoters commonly used for expression of cloned genes. They may also prove useful in the identification of new, ubiquitous cellular transcription factors.
 ...
PMID:Reticuloendotheliosis virus long terminal repeat elements are efficient promoters in cells of various species and tissue origin, including human lymphoid cells. 133 12

Transgenic mice are produced by retroviral insertion, micro-injection in the early embryo, and recently by transfection of embryonic stem cells. Transgenic chickens were only made by retroviral vectors based on avian leukemia virus (ALV) and reticuloendotheliosis (REV) genomes. A replication-defective retroviral vector is preferentially used because these do not induce infectious virus. Since chickens are lacking endogenous REV sequences, a replication defective REV vector is most useful for practical application. Transgenic disease resistance is most likely obtained by blocking of viral receptors. By this approach recently transgenics with resistance against ALV infection were made at the Regional Poultry Disease Laboratory in East Lansing. Inhibition of virus replication by antisense DNA, which is complementary to viral mRNA, is promising for the future. Considerable research efforts still have to be made, however. Production of biomedical proteins will most likely be the first practical use of transgenic chickens. For the time being, vaccines will be used for the control of infectious diseases. The current live-virus vaccines will be replaced by inactivated (sub-unit) vaccines and thereafter by recombinant DNA vaccines based on viral vectors.
 ...
PMID:[Transgenic chickens]. 216 68

Retroviral packaging cell lines were constructed by using the gag-pol gene of spleen necrosis virus, the gag-pol gene of Moloney murine leukaemia virus and the env gene of bovine leukaemia virus. The plasmids containing the gag-pol genes and the plasmid containing the env gene were cotransfected into NIH/3T3 and D17 cells. The cells containing the helper virus constructs were tested for their ability to package replication-defective murine leukaemia and avian reticuloendotheliosis retrovirus vectors. The titre of vector virus produced by each of the retroviral packaging cell lines was about 10(2) colony-forming units per ml of medium. Tests for events that might result in intact replication-competent retroviruses showed no evidence for the generation of such viruses. The vector viruses were able to infect dog and rat cells. Bovine cells were infected only after their cocultivation with the retroviral packaging cell lines producing murine leukaemia virus vectors, perhaps as a result of a low concentration of receptors.
 ...
PMID:Bovine leukaemia virus packaging cell line for retrovirus-mediated gene transfer. 254 78

Avian reticuloendotheliosis virus (REV-T) is the most virulent of all retroviruses, inducing an invariably fatal leukemia in chickens with a latent period of 7-10 days. Unlike avian cells transformed by other acutely transforming viruses, lymphoid cells transformed by REV-T are immortalized. Furthermore, in vitro derived, REV-T transformed cells which do not produce virus are tumorigenic and induce lethal reticuloendotheliosis when injected into histocompatible birds. Thus REV-T transforms its target cell both in vitro and in vivo. In addition this transformation is independent of any helper virus functions. Like other acute leukemia viruses, REV-T is replication-defective and must co-replicate with a reticuloendotheliosis associated virus (REV-A). During evolution, a substantial portion of its genome has been deleted and replaced with a host-derived genetic sequence, designated v-rel. Presumably, the v-rel oncogene was transduced from a normal turkey DNA locus, c-rel. There are 9 regions of homology between c-rel and v-rel, however, several differences exist between these genes, suggesting that transformation by REV-T results from the production of an altered v-rel protein. The v-rel sequence is distinct from other known oncogenes and encodes a 57-kDa phosphoprotein. In REV-T transformed cells, this pp57v-rel protein is localized in the cytoplasm. The product of the v-rel oncogene is present at a low level, representing only about 0.003% of total methionine-labelled protein. In addition, pp57v-rel is relatively stable, having an estimated half-life of 4-10 h. The v-rel protein when purified close to homogeneity is complexed with a 40-kDa cellular phosphoprotein in transformed lymphoid cells and possesses serine kinase activity. This review discusses the molecular aspects of transformation by REV-T in the context of other oncogene-encoded proteins.
 ...
PMID:Transformation of avian lymphoid cells by reticuloendotheliosis virus. 282 14

We describe the case of a patient who developed hairy cell leukaemia (leukaemic reticuloendotheliosis) during phenytoin treatment. Hairy cells were identified by fluorescence, phase contrast and electron microscopy; they contained tartrate-resistant acid phosphatase activity, formed rosettes with mouse but not sheep erythrocytes and bore monoclonal surface immunoglobulin. Because of the association of pseudo- and true lymphomas with phenytoin it is possible that this lymphoproliferative disorder arose as a result of the treatment with phenytoin, possibly in conjunction with sulthiame.
 ...
PMID:Hairy cell leukaemia occurring during phenytoin (diphenylhydantoin) treatment. 286 6


<< Previous 1 2 3 4 5 6 Next >>