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Query: UMLS:C0079731 (B-cell lymphoma)
 16,671 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This report describes a clinical case of a large cell, immunoblastic plasmacytoid malignant B-cell lymphoma of the rectum in an AIDS patient coinfected with HTLV-I. The malignant cells showed clonal genetic rearrangement of the HC (JH) and LCK genes. Infection by EBV was demonstrated serologically and with slot blots using genomic DNA of the cancer cells. Southern blot analysis with DNA extracted from the lymphoma cells were negative for HTLV-I. The patient received seven cycles of VACO-B which induced complete but transient clinical remission of the tumor. The final outcome of the patient is unknown.
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PMID:Primary B cell lymphoma of the rectum in a patient coinfected with HIV-1 and HTLV-I. 128 27

We investigated the association of Epstein-Barr virus (EBV) with African cases of Burkitt's lymphoma (BL) and high grade B cell non-Burkitt's lymphoma (non-BL) occurring in areas where BL is endemic. The presence of EBV genomes was analysed in 24 cases using in situ hybridization with a 35S-labelled EBV probe applied to paraffin sections. EBV DNA was detected in each of 10 cases of BL in which technically satisfactory results were obtained, the virus being homogeneously distributed in all identifiable tumour cells. Two other cases of BL could not be evaluated because of technical problems. In contrast, EBV DNA was not detected in any case of high-grade non-BL (10 centroblastic and two immunoblastic lymphomas). These results confirm previous reports of the strong association of EBV with endemic BL, but suggest that the virus is not important in the pathogenesis of other types of African high-grade B cell lymphoma from regions where BL is endemic.
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PMID:Analysis of African Burkitt's and high-grade B cell non-Burkitt's lymphoma for Epstein-Barr virus genomes using in situ hybridization. 131 Nov 94

The development of a cell culture system efficient in the establishment of lymphoma cell lines has made it possible to dissect basic biological and molecular aspects of lymphoma cells. We have established a lymphoma cell line from a patient with B cell lymphoma. The cell line has a complex karyotype with translocations involving bands 8q24, 14q32, and 18q21. Molecular analysis revealed that the Myc gene was rearranged; we were unable to demonstrate rearrangement of the Bcl-2 gene. Evaluation of the structure of the heavy chain Ig genes revealed that the cell line carried the same rearrangements as the cells from which the cell line was derived. The pattern of rearrangement, however, was unusual in that there were at least four rearranged bands when DNA cut with HindIII was probed with a fragment of the heavy chain joining region. To further characterize the cell line, subclones were derived. Individual subclones had the same pattern of rearrangement as the parent cell line. The results of these studies provide evidence that multiple rearranged Ig genes may be present in a single clone of cells.
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PMID:A human lymphoma cell line with multiple immunoglobulin rearrangements. 131 15

The dbl oncogene was originally identified by transfection of NIH3T3 cells with DNA from a human diffuse B-cell lymphoma. The dbl oncogene product is a cytoplasmic phosphoprotein distributed between the cytosolic and cytoskeletal matrix-associated membrane fractions. Nucleotide sequence analysis has indicated that the predicted dbl product is very hydrophilic with no detectable similarity to known oncogene products. We have more recently discovered that a region of dbl essential for its transforming activity shows significant sequence similarity to a yeast cell cycle gene, CDC24, which is involved in cell polarity and bud formation in the division cycle of Saccharomyces cerevisiae. This sequence similarity suggests a possible role for dbl in cell division. We report here that the dbl oncogene product is able to induce maturation of Xenopus oocytes. Germinal vesicle breakdown (GVBD) was observed when oocytes were microinjected with the soluble fraction of SF9 insect cells infected with a dbl recombinant baculovirus as well as with the in vitro-transcribed dbl mRNA. Moreover, extracts of oocytes microinjected with dbl mRNA showed activation of H1 histone kinase activity. These findings define a new biologic activity of the dbl product and provide the opportunity to analyse dbl interactions with other components of signaling pathways involved in oocyte maturation.
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PMID:Induction of Xenopus oocyte meiotic maturation by the dbl oncogene product. 131 93

To determine whether EBV affects phosphoinositide kinase activities of human B cells, we compared the activities between EBV- and EBV+ human B cell lymphoma lines. The two types of human B cells contained both phosphatidylinositol (PtdIns) 4-kinase and phosphatidylinositol 4-phosphate (PtdIns(4)P) kinase activities irrespective of the presence of EBV. However, both activities were increased in EBV+ cells compared to EBV- cells. The increases were associated with neither altered Km values for substrates nor altered elution profiles in DEAE-cellulose chromatography. Furthermore, expression of a latent EBV protein, EBV nuclear Ag1 (EBNA1) in BHK cells by the transfection of EBNA1 DNA was accompanied by increased PtdIns 4-kinase and PtdIns(4)P kinase activities. These increases also were not associated with altered Km values for substrates. However, phospholipase C activity was altered in neither EBV+ cells nor in EBNA1-expressing cells. These results indicate that EBV selectively increases the two phosphoinositide kinase activities in human B cells, although the viral gene product has no intrinsic phosphoinositide kinase activity. PtdIns 4-kinase and PtdIns(4)P kinase cooperatively synthesize PtdIns 4,5-bisphosphate, the major source of 1,2-diacylglycerol and inositol 1,4,5-triphosphate, the two second messengers in transducing signals for cell activation. Such increase therefore may play a role in EBV-induced human B cell activation.
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PMID:EBV increases phosphoinositide kinase activities in human B cells. 131 98

The EFII cis element is a 38-bp sequence at the 5' end of the Rous sarcoma virus long terminal repeat, extending from nucleotides -229 to -192 (with respect to the viral transcription start site), which is recognized by sequence-specific DNA-binding proteins in avian fibroblast nuclear extracts (L. Sealy and R. Chalkley, Mol. Cell. Biol. 7:787-798, 1987). We demonstrate that multiple copies of the EFII cis element strongly activate transcription of a reporter gene in vivo. We correlate the region of the EFII cis element which activates transcription in vivo with the in vitro binding site for three nuclear factors, EFIIa, EFIIb, and EFIIc. The sequence motif recognized by EFIIa, -b, and -c is also found in consensus binding sites for members of a rapidly growing family of transcription factors related to the CCAAT/enhancer-binding protein (C/EBP). EFIIa, -b, and -c are present in fibroblast and epithelial cell lines from various species but are much less abundant in differentiated rat liver and kidney cells. The EFIIa binding activity is particularly abundant in an avian B-cell lymphoma line. As judged from molecular weight analysis, cell type distribution, and sequence recognition properties, the EFII factors under study appear to differ from most of the previously described C/EBP-related factors and thus may expand the diversity of the C/EBP family.
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PMID:Characterization of nuclear proteins that bind the EFII enhancer sequence in the Rous sarcoma virus long terminal repeat. 132 70

In the A20/2J BALB/c B cell lymphoma, Southern analysis revealed an insertion of approximately 6 kilobases of DNA into the first intron of one Ebd-allele. Two observations suggest that the rearrangement did not occur recently in the A20/2J subline. Firstly, normal and altered Ebd-alleles are present in equal numbers, and secondly, the LB 27.4 and LS 102.9 somatic cell hybrids formed at an earlier date both possess the rearrangement. Sequences of two cDNA clones, lambda Eb-7 and lambda Eb-125, selected from an A20/2J cDNA library prepared from poly [A+] RNA indicate that the rearranged Ebd-allele directs the synthesis of atypical Eb transcripts. The clones contain Eb sequence linked to a portion of retroviral-like intracisternal A-particle (IAP) genomic sequence, and they appear to be copies of mRNA produced by splicing between a 5' donor site in the retroviral transcript and the 3' acceptor site of the Eb gene's first intron. The longer lambda Eb-125 insert corresponds to RNA that initiated in the 5'-untranslated region of the Eb gene. The 3'-end of the first Eb exon joins to long terminal repeat sequence, and retroviral sequence extends up to the splice junction with the second Eb exon; 3' of the junction, the lambda Eb-125 sequence corresponds to that of a correctly spliced Eb transcript. It seems feasible that the cDNA clones represent hybrid RNA synthesized by read-through transcription of the Eb coding region and an IAP element inserted into the first intron of the rearranged Ebd-allele.
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PMID:Interaction of H-2Eb with an IAP retrotransposon in the A20/2J B cell lymphoma. 135 78

Fifteen endoscopic gastric biopsies (GBx) from 12 patients with small lymphocytic infiltrates morphologically raising a differential of indeterminate lymphocytic infiltrate versus mucosa-associated lymphoid tissue (MALT) lymphoma were analyzed genotypically after frozen-section identification of the abnormal lymphocytic infiltrate. Frozen-section immunoperoxidase immunophenotyping was equivocal in each case. All patients had abdominal pain attributable to superficial gastric ulceration, most often antral, without peripheral lymphadenopathy or hepatosplenomegaly. Rearrangement of the immunoglobulin heavy-chain gene (JH-R, seven patients) or kappa light-chain gene (JK-R, eight patients), was found in eight GBx from eight (seven stage IAE; one stage IBE) of 12 patients, establishing, in conjunction with the histologic features, a diagnosis of low-grade B-cell lymphoma. This diagnosis had not been tenable on multiple prior GBx, ranging from one to five per patient, over intervals of 1 month to 6.5 years (median 4.5 months). The T-cell receptor beta-chain gene retained germline configuration in all cases. Insufficient DNA for molecular studies was extracted from the GBx of two patients, one with JK-R (JH-G) on subsequent GBx and one without further GBx. One patient had two GBx, each demonstrating a single additional band in HindIII digests hybridized with the JH probe. No rearrangements were detected in either the BamHI or the EcoRI digests. Uninvolved tissue from this patient was not available for the exclusion of restriction fragment length polymorphism. Three GBx (two patients) showed germline JH genes (JH-G). One had a partial gastrectomy (histology: MALT lymphoma) in 1981 followed by GBx in 1983 (histologically benign) and in 1990 (JH-G), and negative esophagogastroduodenoscopy (EGD) in 1991 without biopsy. The other patient (two GBx with JH-G) had multiple subsequent abnormal EGD, but no biopsies since December 18, 1990. Adequate DNA for gene rearrangement studies can be extracted from GBx samples weighing as little as 20 mg. The two samples with insufficient DNA weighed 1 and 16 mg, respectively. Practically speaking, the remainder of a frozen block from a single GBx is adequate, thus allowing the screening of multiple endoscopic GBx by sequential frozen sections to determine which one contains the most extensive lymphocytic infiltrate for molecular study. Consistent results are obtained on samples weighing 40 to 60 mg. This method is a suitable alternative to kappa/lambda frozen-section immunoperoxidase immunostaining, which can be uninterpretable on endoscopic biopsies or small biopsies from other sites.
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PMID:Practicality of molecular studies to evaluate small lymphocytic proliferations in endoscopic gastric biopsies. 135 96

Four allelic forms of the immunoglobulin lambda light chain constant region (C lambda) genes are found in the caucasoid population and are recognised by the presence of Eco RI restriction fragments of sizes 8, 13, 18, and 23 kb hybridising with a C lambda probe. The less common allelic forms of the C lambda genes are marked by the 13, 18, and 23 kb fragments, and these may be misinterpreted as rearranged fragments derived from a monoclonal population of B-cells. The 13, 18, and 23 kb alleles result from the insertion of one, two, and three copies, respectively, of a 5.2 kb repeat unit that can be demonstrated by hybridising genomic DNA digested with Hind III with a C lambda probe. Using selected histologically and immunophenotypically well-defined cases, we assessed the usefulness of the 5.2 kb Hind III/C lambda fragment in distinguishing between rearrangements indicative of a B-cell lymphoma and germline configurations representing uncommon allelic forms of the C lambda genes. From these studies, we conclude that Hind III digestion should routinely be performed when using the C lambda probe to assess B-cell monoclonality. Identification of the 5.2 kb Hind III fragment obviates the need to examine DNA from normal peripheral blood granulocytes to exclude allelism of the C lambda genes in cases exhibiting the uncommon restriction fragments after Eco RI digestion.
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PMID:Distinguishing between monoclonal rearrangements and allelic forms of the immunoglobulin lambda light chain constant region genes. Significance in the diagnosis of non-Hodgkin's lymphoma. 136 71

Specific DNA probes for genes encoding immunoglobulins (Ig) and the T cell receptor (TCR) are useful diagnostic tools in lymphoproliferative disorders. Gene rearrangement analysis was carried out in 2 cases of conjunctival lymphoid lesions. A 36-year-old man (case 1) had a 1-year history of left conjunctival tumor. A biopsy was performed and histopathological findings showed diffuse proliferation of small lymphocytes, but monoclonality was not revealed by immunophenotypic analysis. A right conjunctival lesion developed and five months later a biopsy of the left conjunctiva was performed again. A frozen sample was analyzed and immunoglobulin heavy chain gene rearrangement was found. A 53-year-old woman (case 2) had a 6-month history of bilateral conjunctival tumor. The first biopsy did not reveal monoclonality immunophenotypically. A second biopsy with a frozen specimen was analyzed and immunoglobulin heavy chain gene rearrangement was found. We diagnosed these two cases as B-cell lymphoma. We discuss the clinical value of gene rearrangement analysis as a diagnostic method for lymphoproliferative disorders.
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PMID:[Gene rearrangement analysis of conjunctival malignant lymphomas]. 141 4


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