Biomedical subjects

B H Ye

Publications and source records attributed to B H Ye.

35 records · Page 2Linked to original sources

PubMed1995

A specific monoclonal antibody (PG-B6) detects expression of the BCL-6 protein in germinal center B cells.

The BCL-6 gene is frequently involved in translocations occurring at the 3q27 locus and is rearranged in approximately 30% of diffuse large cell lymphomas and in a small fraction of follicular lymphomas. The BCL-6 gene encodes for a Kruppel-type zinc-finger protein, the cell/tissue expression and function of which is unknown. In this study, we describe a new monoclonal antibody (PG-B6) that is specifically directed against a fixative-sensitive epitope on the amino-terminal region of the BCL-6 protein. By immunocytochemical analysis, BCL-6 localizes in the nucleus where PG-B6 staining gives a microgranular/diffuse pattern with exclusion of the nucleoli. The main reactivity of PG-B6 in tonsil and spleen is with the nuclei of germinal center B cells, whereas B cells within the mantle and marginal zones do not express BCL-6. No other lymphoid cells in the tonsil express BCL-6 except for a subset of CD3+/CD4+ intrafollicular and interfollicular T cells. A few lymphoid cells of unknown phenotype express BCL-6 in the thymus. Extra-lymphoid BCL-6 expression includes a weak nuclear positivity of epithelia. In non-Hodgkin's lymphomas, BCL-6 expression parallels that observed in normal lymphoid compartments, eg, expression in germinal center-derived tumors (follicular and diffuse large cell lymphomas), but not in mantle cell and marginal zone lymphomas. In most diffuse large cell lymphomas, the BCL-6 protein is expressed at high levels in cases with or without BCL-6 gene rearrangements. These findings indicate that BCL-6 expression is specifically regulated during B lymphocyte development and suggest that BCL-6 may play a role during B cell differentiation in the germinal center.

Animals↗

PubMed1994

Rearrangements of the BCL-6 gene in acquired immunodeficiency syndrome-associated non-Hodgkin's lymphoma: association with diffuse large-cell subtype.

Acquired immunodeficiency syndrome (AIDS)-associated non-Hodgkin's lymphomas (AIDS-NHL), a major source of morbidity and mortality among AIDS patients, are derived from B cells and can be classified into two main histologic categories, small noncleaved cell lymphoma (SNCCL) and diffuse large-cell lymphoma (DLCL). DLCL includes two histologic subsets, ie, large noncleaved cell lymphoma (LNCCL) and large cell-immunoblastic plasmacytoid lymphoma (LC-IBPL). Several studies have shown that AIDS-SNCCL is associated with the clonal accumulation of multiple genetic lesions, including Epstein-Barr virus (EBV) infection, activation of the c-MYC and RAS oncogenes, as well as inactivation of the p53 tumor suppressor gene at variable frequencies. On the contrary, the molecular pathogenesis of AIDS-DLCL is largely obscure, because no genetic lesion other than EBV infection has been specifically identified in this group. In this study, we have tested a panel of 40 AIDS-NHL for structural alterations of BCL-6, a putative proto-oncogene that is frequently altered in DLCL in the immunocompetent host. Our results show that rearrangements of BCL-6 are present in 20% of AIDS-DLCL (5 of 24), including 2 of 8 LNCCL and 3 of 16 LC-IBPL, but in no case of AIDS-SNCCL. BCL-6 rearrangements were detected both in the presence and in the absence of EBV infection of the tumor clone, but in no case were associated with activation of c-MYC or mutations of p53. These data identify a novel genetic lesion in AIDS-DLCL and corroborate the notion that lymphomagenesis in AIDS follows two distinct molecular pathways that are associated with the development of histologically distinct types of AIDS-NHL.

DNA-Binding Proteins↗

PubMed1994

Rearrangement of the bcl-6 gene as a prognostic marker in diffuse large-cell lymphoma.

BACKGROUND: About 40 percent of non-Hodgkin's lymphomas are diffuse lymphomas with a large-cell component (DLLC). Current therapy can induce a long-term remission in half the patients with DLLC, but more intensive treatment has the potential to improve outcome, particularly in patients at high risk for treatment failure. Clinical and cytogenetic markers can identify subgroups at high or low risk. Rearrangement of a novel candidate proto-oncogene, bcl-6, is a possible prognostic indicator in DLLC. METHODS: We performed Southern blot hybridization to detect bcl-6 and bcl-2 gene rearrangement in samples of lymphoma from 102 patients with B-cell DLLC. The results were correlated with the patients' histologic features, age, disease stage, tumor sites and bulk of disease, serum lactate dehydrogenase level, and treatment outcome. RESULTS: Rearranged bcl-6 was found in 23 cases, and rearranged bcl-2 in 21 cases. Nineteen of the patients with rearranged bcl-6 had extranodal DLLC, two had primary splenic lymphomas, and only one had bone marrow involvement. Thirty-six months after diagnosis, the proportion with freedom from progression of disease was projected to be 82 percent (95 percent confidence interval, 66 to 98 percent) among the patients with rearranged bcl-6, as compared with 56 percent (95 percent confidence interval, 43 to 70 percent) for the patients with germ-line bcl-6 and bcl-2 and 31 percent (95 percent confidence interval, 8 to 53 percent) for the patients with rearranged bcl-2. The status of the bcl-6 gene was an independent prognostic marker of survival and freedom from disease progression in a multivariate model and added predictive value to established prognostic signs. CONCLUSIONS: Rearrangement of the bcl-6 gene correlated with a favorable clinical outcome in DLLC and may thus serve as a prognostic marker in patients with this form of malignant lymphoma.

Aged↗

PubMed1994

Rearrangements of the BCL6 gene in diffuse large cell non-Hodgkin's lymphoma.

The pathogenesis of non-Hodgkin's lymphoma (NHL) with a large cell component (DLLC, including diffuse large cell, DLCL; diffuse mixed cell, MX-D; and immunoblastic, IMB) is unknown. A novel candidate proto-oncogene, BCL6, that is involved in chromosome band 3q27 aberrations in NHL has been recently identified. We have investigated the incidence and disease-specificity of BCL6 rearrangements in a large panel of lymphoid tumors, including acute and chronic lymphoid leukemias (96 cases), various NHL types (125 cases), and multiple myelomas (23 cases). BCL6 rearrangements were found in 16/45 (35.5%) DLLC, more frequently in DLCL (15/33, 45%) than in MX-D (1/10, 10%), in 2/31 (6.4%) follicular NHL, and in no other tumor types. BCL6 rearrangements represent the first genetic lesion specifically and recurrently associated with DLLC and should prove useful for understanding the pathogenesis as well as for the clinical monitoring of these tumors.

DNA-Binding Proteins↗

PubMed1994

Identification of genetic lesions associated with diffuse large-cell lymphoma.

BACKGROUND: The pathogenesis of several subtypes of non-Hodgkin's lymphoma (NHL) is associated with specific genetic lesions involving oncogenes and tumor-suppressor genes. These lesions include c-myc translocation and p53 inactivation in small noncleaved-cell lymphoma, and bcl-2 and bcl-1 translocation in follicular (FL) and mantle-zone lymphoma, respectively. Relatively little is known, however, about the pathogenesis of diffuse lymphoma with a large-cell component (DLLC; including large-, mixed-cell, and immunoblastic), the most relevant NHL type in terms of morbidity and mortality. Since DLLC can occur 'de novo' or via histologic transformation of follicular lymphoma, it is critical to identify lesions associated with both pathogenetic pathways. DESIGN: The present work is aimed at (i) identifying the role of cytogenetic and molecular lesions involving oncogenes or tumor-suppressor genes in the transformation of FL into DLLC in a series of 5 patients for whom sequential biopsies were available pre- and post-transformation and (ii) identifying novel proto-oncogenes involved in DLLC pathogenesis by molecular analysis of chromosomal translocations affecting band 3q27, which are common in DLLC. RESULTS: Mutations of the p53 gene were detected in 4 of 5 cases displaying histologic transformation from follicular to diffuse-type NHL. A novel proto-oncogene, bcl-6, coding for a zinc-finger transcription factor, was cloned from 3q27 breakpoints and shown to be structurally altered in 33% (13/39) of DLLC samples studied, but not in other types of lymphoid malignancies. CONCLUSIONS: These results indicate that inactivation of the p53 tumor-suppressor gene may complement bcl-2 activation and be involved in the transformation of FL into DLLC. Activation of the bcl-6 oncogene may represent one of the steps in the pathogenesis of 'de novo' DLLC. Both lesions should prove useful as diagnostic and prognostic markers in the clinical management of these tumors.

Humans↗

PubMed1994

BCL-6 and the molecular pathogenesis of B-cell lymphoma.

The results presented identify the first genetic lesion associated with DLCL, the most clinically relevant form of NHL. Although no proof yet exists of a role for these lesions in DLCL pathogenesis, the feature of the BCL-6 gene product, its specific pattern of expression in B cells, and the clustering of lesions disrupting its regulatory domain strongly suggest that deregulation of BCL-6 expression may contribute to DLCL development. A more precise definition of the role of BCL-6 in normal and neoplastic B-cell development is the goal of ongoing study of transgenic mice engineered either to express BCL-6 under heterologous promoters or lacking BCL-6 function due to targeted deletions. In addition to contributing to the understanding of DLCL pathogenesis, the identification of BCL-6 lesions may have relevant clinical implications. DLCL represent a heterogeneous group of neoplasms which are treated homogeneously despite the fact that only 50% of patients experience long-term disease-free survival (Schneider et al. 1990). The fact that BCL-6 rearrangements identify biologically and clinically distinct subsets of DLCL suggests that these lesions may be useful as markers in selection of differential therapeutic strategies based on different risk groups. Furthermore, the BCL-6 rearrangements can be used to identify and monitor the malignant clone with sensitive PCR-based techniques. Since clinical remission has been observed in a significant fraction of DLCL cases, these markers may serve as critical tools for sensitive monitoring of minimal residual disease and early diagnosis of relapse (Gribben et al. 1993).

Animals↗

PubMed1994

[The mosquitocidal efficacy of microcapsules of alpha-cypermethrin against Anopheles sinensis].

The efficacy of spraying of alpha-cypermethrin microcapsule for the control of Anopheles sinensis was investigated when alpha-cypermethrin microcapsule was sprayed at 0.5 g/m2, the KT50 was 7.9 min and a 100% of 24 hours' mortality of An. sinensis, the efficacy being similar to that of the emulsion. 180 days after spray, the KT50 was 28.2 min, the 24 hours' mortality was 85.7%, the residual efficacy was 3 times over that of the emulsion. In the mimic field experiment, similar results were obtained. In the field trial, the residual efficacy of the alpha-cypermethrin microcapsule was 5.9 times that of the emulsion. Alpha-cypermethrin microcapsules is recommended as a good formulation of mosquitocide for mosquito control, considering its mosquitocidal efficacy and residual efficacy.

Animals↗

PubMed1993

Alterations of a zinc finger-encoding gene, BCL-6, in diffuse large-cell lymphoma.

The molecular pathogenesis of diffuse large-cell lymphoma (DLCL), the most frequent and clinically relevant type of lymphoma, is unknown. A gene was cloned from chromosomal translocations affecting band 3q27, which are common in DLCL. This gene, BCL-6, codes for a 79-kilodalton protein that is homologous with zinc finger-transcription factors. In 33 percent (13 of 39) of DLCL samples, but not in other types of lymphoid malignancies, the BCL-6 gene is truncated within its 5' noncoding sequences, suggesting that its expression is deregulated. Thus, BCL-6 may be a proto-oncogene specifically involved in the pathogenesis of DLCL.

Amino Acid Sequence↗

PubMed1993

Cloning of bcl-6, the locus involved in chromosome translocations affecting band 3q27 in B-cell lymphoma.

Chromosomal translocations involving band 3q27 and various chromosomal sites, including the sites of the immunoglobulin (Ig) loci (14q32, 2p12, 22q11), represent recurrent aberrations in non-Hodgkin's lymphoma (NHL). In order to identify the putative protooncogene involved in these translocations, we have cloned the breakpoints from two B-cell NHL cases carrying t(3;14)(q27;q32) translocations by screening genomic DNA libraries constructed from NHL biopsy samples with immunoglobulin probes. Several recombinant phages have been obtained from each case and shown to contain sequences from both 14q32 and 3q27 by fluorescence in situ hybridization mapping on metaphase chromosomes. In both cases, the translocation breakpoints were found within the switch region of the Ig heavy-chain locus on 14q32 and within the same 3-kilobase region on 3q27. When used in Southern blot hybridization, a probe from the 3q27 region detected rearrangements in an additional five NHL cases carrying 3q27 translocations with 14q32 or other genomic sites. The same probe detected a predominant 2.4-kilobase mRNA species in several lymphoid cell lines analyzed by Northern blot hybridization. These data suggest that chromosomal breakpoints in 3q27 cluster in the proximity of a transcribed gene which represents a candidate protooncogene (bcl-6) involved in B-cell NHL pathogenesis.

Chromosomes, Human, Pair 14↗

PubMed1993

[Analysis of the protein/polypeptide in Culex pipiens pallens (Diptera:Culicidae) during hibernation by two-dimensional gel electrophoresis].

Analysis on the protein/polypeptide in Culex pipiens pallens (Diptera: Culicidae) caught from the resting or overwintering places during the 3rd ten-day of September, the 2nd ten-day of December and the 1st ten-day of March in next year in Zhengzhou (34 degrees 43' N, 113 degrees 39' E) during hibernation by two-dimensional gel electrophoresis indicated that there were 153, 118 and 169 protein/polypeptide spots in unoverwintering, overwintering and recovering mosquitoes respectively. The molecular weight (MW) of most of the spots was less than 43.0 kDa, with isoelectric points (pI) between 5.65-7.34. The comparisons between each two types of mosquitoes during hibernation revealed that the variant rate of protein/polypeptide spots between overwintering and recovering mosquitoes (31.01%) was significantly higher than that between unoverwintering and recovering females (21.12%) (P < 0.05). The variant spots were 13 in unoverwintering, 7 in overwintering and 27 in recovering mosquitoes respectively. The comparisons among three types of mosquitoes during hibernation showed that the variant rate was significantly higher in recovering females (15.98%) than in unoverwintering (8.50%) (P < 0.05) and overwintering females (5.93%) (P < 0.01). The total variant rate of protein/polypeptide spots of all these three types of mosquitoes was 10.68%. Because the blood meal of all the mosquitoes used for homogenization was at Sella 1 (empty), and the ovary development was under Christophers II (resting stage), the experimental results were not affected by blood meal and the later ovary development (Christophers II-V).

Animals↗

PubMed1993

[Variations of free amino acids in hemolymph of Culex pipiens pallens during overwintering period].

An analysis of the amino acids present in the hemolymph of Culex pipiens pallens caught from resting or overwintering places (blood meal: Sella 1, i.e. empty; ovary stage: under Christophers IIb) in Zhengzhou (34 degrees 43'N, 113 degrees 39E) indicated that 19, 18 and 18 kinds of free amino acids (FAAs) were detected during stages of preoverwintering, overwintering and postoverwintering respectively. Comparison of hemolymph amino acids between overwintering and preoverwintering stages revealed that the concentrations of the total FAAs and FAAs reduced significantly in overwintering except cystine and proline. The concentrations of cystine and proline during preoverwintering were 0.1563 +/- 0.0021 nmol/microliter and 22.2467 +/- 1.3537 nmol/microliter, but 0.2067 +/- 0.0058 nmol/microliter and 36.5467 +/- 0.4654 nmol/microliters during overwintering respectively. Comparison of hemolymph amino acids between postoverwintering and overwintering stages showed that the concentrations of all FAAs and total FAAs increased significantly during postoverwintering stage, and the concentrations of aspartic acid, glumatic acid, alanine, cystine, proline and total FAAs even exceeded those during preoverwintering stage respectively.

Amino Acids↗

PubMed1992

[Comparison of mosquito larvicidal efficacy between microbial encapsulated BTI (EBTI) and standard BTI (SBTI)].

A comparative study was conducted on the efficacy of mosquito larvicides EBTI and SBTI. The results showed that: 1. The residual efficacy of EBTI was remarkably higher than that of SBTI at 0.007-0.002ppm BTI concentration (P < 0.01), the mosquito larvae mortality of EBTI remained 100% until the 4th week; in contrast, the mosquito larva mortality of SBTI gradually and obviously declined from the 2nd to 4th week after treatment (x2 = 8.17-24.08), and reached 0 at the 4th week. 2. The lowest BTI concentration of EBTI at which a high efficacy persisted for 4 weeks was 0.007ppm BTI, the mosquito larva mortality remaining 100%.

Animals↗

PubMed1989

[Comparative studies on several biochemical indices of Anopheles anthropophagus and Anopheles sinensis].

Proteins, sugars and esterase isoenzymes of An. anthropophagus and An. sinensis were compared by IEF and two dimensional gel electrophoresis. The results show that there are some differences in the electrophoretic patterns between An. anthropophagus and An. sinensis. The glycoprotein, lipid protein, glycolipidprotein, protein, polysaccharide and esterase isoenzymes showed 10, 0, 6, 14, 2 and 13 bands in An. anthropophagus; 10, 1, 5, 16, 3 and 15 in An. sinensis. There exist 234 and 240 polypeptide spots in An. anthropophagus and in An. sinensis, respectively, altogether 27.8% of polypeptide spots being different.

Animals↗

PubMed1988