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  • 1
    Keywords: CANCER ; CELLS ; EXPRESSION ; CELL ; Germany ; neoplasms ; GENE ; GENE-EXPRESSION ; GENES ; transcription ; cell line ; MESSENGER-RNA ; primary ; recombination ; SEQUENCE ; SEQUENCES ; TARGET ; LYMPHOMA ; MALIGNANCIES ; UP-REGULATION ; CELL-LINE ; LINE ; LYMPHOCYTES ; INSTABILITY ; SOMATIC HYPERMUTATION ; B-CELL LYMPHOMA ; GENOMIC INSTABILITY ; HIGH-LEVEL ; MALIGNANCY ; ONCOLOGY ; RE ; COSTIMULATION ; LEVEL ; AID ; USA ; GERMINAL-CENTER ; B-LYMPHOCYTES ; cancer research ; HODGKIN LYMPHOMA ; genomic ; B-CELL ; LIMIT ; ACCESSIBILITY ; DIVERSIFICATION ; CLASS SWITCH RECOMBINATION ; SWITCHES ; ANTIBODY DIVERSIFICATION ENZYME ; CLASS-SWITCH RECOMBINATION ; DNA DEAMINATION ; HIGH-LOAD ; mediastinal B-cell lymphoma
    Abstract: Activation-induced cytidine deaminase (AID) initiates somatic hypermutation (SHM) and class switch recombination (CSR) in activated B lymphocytes and is potentially implicated in genomic instability of B-cell malignancies. For unknown reasons, B-cell neoplasms often lack SHM and CSR in spite of high MD expression. Here, we show that primary mediastinal B-cell hTnphoma (PMBL), an immunoglobulin (Ig)-negative lymphoma that possesses hypermutated, class-switched Ig aenes. expresses high levels of AID with an intact primary structure but does not do CSR in 14 of 16 cases analyzed. Absence of CSR coincided with low Ig germ-line transcription, whereas high level germ-line transcription was observed only in those two cases with active CSR. Interleukin-4/CD40L costimulation induced CSR and a marked up-regulation of,germ-line transcription in the PMBL-derived cell line MedB-1. In the PMBL cell line Karpas 1106P, CSR was not inducible and germ-line transcription remained low on stimulation. However, Karpas 1106P, but not MedB-1, had ongoing SHM of the Ig gene and BCL6. These genes were transcribed in Karpas 1106P, whereas transcription was undetectable or low in MedB-1 cells. Thus, accessibility of the target sequences seems to be a major limiting factor for AID-dependent somatic gene diversification in PMBL
    Type of Publication: Journal article published
    PubMed ID: 17638864
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  • 2
    Keywords: EXPRESSION ; SURVIVAL ; GENE ; PROTEIN ; LYMPHOMA ; MELANOMA ; FEATURES ; HUMAN CANCER ; CLINICAL-PRACTICE ; VEMURAFENIB
    Abstract: Detection of BRAF V600E has diagnostic, prognostic, and therapeutic relevance. The recently developed BRAF V600E mutation-specific antibody has evolved into a feasible alternative to DNA analysis. The plethora of immunohistochemical protocols makes implementation tedious and, here we tested a set of manual and automated protocols and compared test performance with sequencing results. For assays, we employed formalin-fixed, in part decalcified, and paraffin-embedded tissue samples. Empiric testing of manual protocols included 10 variables in 17 protocols. Automated immunohistochemical staining and BRAF pyrosequencing served as independent test methods. Test performance measures were compared without considering 1 method as a standard. Four well-fixed samples (2WT/2Mut) were used for testing of all protocols and indicated 2 correctly classifying procedures. Practical performance assessment employed 33 independent tissue samples, composed of 27 leukemias (by pyrosequencing: 8 wild-type; 18 mutated; 1 noninformative) and 6 melanomas (V600E; V600K; wild-type, 2 each). Manual V600E staining was positive in 20 cases (19 of 20 V600E-containing samples plus the 1 sample that was noninformative), whereas all wild-type and V600K cases were immunonegative. Manual or automated staining as well as pyrosequencing would have missed an equal number of V600E-mutated cases and the correlation coefficient for these methods was 0.75 to 0.93 (substantial to almost perfect); the Youden index was 0.95. Detection of V600E-mutated BRAF at the protein level in routine and decalcified tissue samples is possible, and the presented manual protocols should expedite implementation in routine diagnostic practice. Our results indicate that both molecular techniques should be considered complementary.
    Type of Publication: Journal article published
    PubMed ID: 25611237
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  • 3
    Keywords: CELLS ; EXPRESSION ; Germany ; POPULATION ; SITE ; GENE ; PROTEIN ; MONOCLONAL-ANTIBODY ; TISSUE ; recombination ; T-CELLS ; immunohistochemistry ; MALIGNANCIES ; B-CELLS ; PHENOTYPE ; RT-PCR ; ANTIBODY-RESPONSES ; MALIGNANCY ; thymus ; SUBSET ; LEVEL ; LYMPHOMAS ; lymph node ; LYMPH-NODE ; INDUCED CYTIDINE DEAMINASE ; IMMUNOGLOBULIN CLASS-SWITCH
    Abstract: Neoplastic transformation of mature B cells can be triggered by class-switch recombination of the immunoglobulin gene, which aberrantly targets a protooncogene and promotes translocation. Class-switch recombination is initiated by the B-cell-specific protein activation-induced cytidine deaminase (AID). Using immunohistochemistry with a newly generated monoclonal antibody and quantitative reverse-transcription-polymerase chain reaction (RT-PCR) on microdissected tissue from lymph node, tonsil, and thymus, we demonstrate that AID expression is found in secondary lymphoid organs outside germinal centers and in the thymic medulla at substantial levels. This is accompanied by the presence of circle transcripts, indicating class-switch recombination to be active at these sites. The dominant AID-expressing cell population outside germinal centers displays cytomorphologic properties corresponding to those that define the recently characterized interfollicular large B-cell subset. These findings indicate that interfollicular large B cells and AID-expressing B lymphocytes of the thymic medulla could give rise to mature B-cell malignancies
    Type of Publication: Journal article published
    PubMed ID: 16269615
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  • 4
    ISSN: 1435-2451
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung 0 1. Es werden drei Typen vonHerz-Lungen-Präparationen besprochen, mit deren Hilfe es möglich ist, am spontan schlagenden Herzen über längere Zeit die funktionierenden Klappen in direkter Sicht zu beobachten, zu filmen und auszumessen. Das Herz pumpt eine klare, durchsichtige, möglichst dem Blut isotonische Flüssigkeit, durch die die Klappen und sonstige anatomische Einzelheiten gut zu sehen sind (Experimentierkreislauf). Der das Myokard versorgende Coronarkreislauf (Ernährungskreislauf) wird von diesem Flüssigkeitskreislauf teilweise oder vollständig getrennt. Hierdurch wird die Überlebensdauer des physiologisch normal reagierenden Herzens auf mehrere Stunden ausgedehnt. 2. An derartigen Herzpräparaten wurde insbesondere diesystolische Kontraktion des Mitralklappenringes gefilmt und ausgemessen. Diese systolische Verkürzung der Klappensegelbasis ist am leerschlagenden Herzen sowie nach Gabe von Adrenalin oder Calcium besonders ausgeprägt. Die murale Circumferenz des Klappenringes verkürzt sich wesentlich stärker als die aortalen Anteile. Hieraus ergeben sich wichtige Rückschlüsse auf die Funktion der Klappen und der Chordae tendineae sowie des Klappenringes im Kontraktionsablauf des Herzens.
    Type of Medium: Electronic Resource
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