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Biomedical subjects

R Fischer

Publications and source records attributed to R Fischer.

At least 415 records · Page 23Linked to original sources
PubMed1992

[Which are the proliferating cells in Hodgkin's disease?].

This investigation characterizes the proliferating cells in Hodgkin's disease. We used the antibody PC 10 which reacts with the proliferating cell nuclear antigen (PCNA) and works on paraffin sections in combination with B- and T-cell markers in a double-staining technique. In all 38 cases of Hodgkin's disease (lymphocyte predominant type n = 10, nodular sclerosis type n = 10, mixed cellularity type n = 10, lymphocyte depletion type n = 8) a high percentage of the Hodgkin and Sternberg-Reed cells (95%-97%) expressed PCNA. There was no statistical significance between the different types. In contrast, only a small amount of the reactive lymphocytes (2.8%-3.4%) demonstrated positivity for PCNA in the four types of Hodgkin's disease. Nearly all of these lymphocytes were T-lymphocytes.

Antigens, CD↗
PubMed1992

[Borderline between Hodgkin and non-Hodgkin lymphomas with unfavorable clinical course: a clinical, histological and immunohistochemical analysis of 33 cases within the German Hodgkin Lymphoma Study].

Reevaluation of diagnostic biopsies from 502 patients who entered the German Hodgkin Therapy trial was performed by a panel of four pathologists. Classification revealed 90% of unambiguous Hodgkin-lymphomas (HL), 1.6% of Non-Hodgkin-lymphomas (NHL) and 8.4% of cases difficult to evaluate, reflecting to the well-known problem of the border between these 2 groups of lymphoma. As these cases had the worst prognosis, a second attempt of reclassification, including immunohistochemical studies, was made, resulting in final classifying of 25% of these cases as NHL, 50% as HL, and 25% as further unclassifiable. The most common differential diagnostic problem was separating pleomorphic nodular sclerosing HL from large cell NHL's and HL with rather few Hodgkin- or Reed-Sternberg-cells from Lennerts lymphoma or angioimmunoblastic lymphadenopathy. Immunohistochemistry was helpful for the differential diagnostic decisions in these individual cases. A very high percentage of these problem cases had initially entered the trial as lymphocyte depleted HL, and the large majority of deaths came from the large cell NHL group.

Diagnosis, Differential↗
PubMed1992

[Bcl-2 in potentials precursors of nodular paragranuloma and its dedifferentiated variant (large cell B-lymphoma)].

We have investigated seven cases of large cell lymphomas (LCL) developing simultaneously or metachronously to nodular lymphocyte-predominant Hodgkin's disease (nodular paragranuloma, NP) for the presence of EBV and the chromosomal translocation t(14;18) by use of the polymerase chain reaction (PCR). The expression of the bcl-2 oncogene product in these cases and in five cases of progressive transformation of germinal centres as a potential precursor of NP was detected immunohistochemically with the monoclonal antibodies bcl-2-100 and bcl-2-124. All cases investigated were negative for EBV genomic material. The chromosomal translocation t(14;18) was also absent. Expression of the bcl-2 oncogene could be detected only in one case of nodular paragranuloma and in an unrelated case of LCL. Hence, LCL developing out of NP differ from other germinal center derived high-grade lymphomas.

Adult↗
PubMed1992

[Influence of Epstein-Barr virus genome on patient survival in Hodgkin's disease].

In the literature EBV is considered a possible etiologic factor for Hodgkin's disease (HD). We investigated 187 cases of HD for the presence of Epstein Barr virus using the polymerase chain reaction (PCR) technique on formalin fixed, paraffin embedded lymph node tissue to clarify the clinical importance of the incidence of this genome. The 187 cases included all subtypes. 66 cases (35.2%) were positive for EBV DNA. The statistical analysis of follow-up data from 130 patients revealed no influence of EBV DNA on survival time. In our investigation detection of EBV DNA by PCR showed no prognostic relevance for patients with HD.

DNA, Neoplasm↗
PubMed1992

[Nodular paragranuloma and Epstein-Barr virus: frequency of EBV DNA and clinical relevance].

Studies demonstrating Epstein-Barr virus (EBV) DNA in Hodgkin's disease (HD) provide little information about the EBV-status in the lymphocyte predominant subtype (nodular paragranuloma) which is due to the small number of cases investigated. Therefore we studied 99 typical cases of nodular paragranuloma for the presence of EBV-DNA using the polymerase chain reaction (PCR) technique. Genomic DNA was amplifiable in 71 cases; 29 cases (= 40%) were positive for EBV-DNA (EBNA-1). In situ hybridization revealed EBV-RNA (EBER-1) in L&H cells and in a few lymphocytes. PCR results were correlated to clinical follow-up data and did not show any statistically significant relationship between EBV positivity and survival of the patients.

Adult↗
PubMed1992

[Follicular dendritic cells in extranodal non-Hodgkin's lymphomas].

Extranodal lymphomas of the thyroid (n = 19), kidney (n = 15) and testis (n = 30) were investigated histologically and immunohistochemically using the monoclonal antibody Ki-FDC1P, which recognizes follicular dendritic cells on paraffin sections. Only lymphomas of the thyroid were of MALT-lymphoma type and contained tumor associated abortive follicles of follicular dendritic cells. In kidney and testis, no MALT-Lymphomas were found. Lymphoepithelial lesions, a hallmark of MALT-Lymphomas, occurred not only in thyroid MALT-lymphomas, but also in testicular centroblastic lymphomas (lacking other features of MALT-lymphomas). Therefore, lymphoepithelial lesions are not specific for MALT-lymphomas.

Antibodies, Monoclonal↗
PubMed1992

[Detection of clonal immunoglobulin rearrangements in paraffin embedded tissues by PCR].

A polymerase chain reaction based method was established using immunoglobulin VH and VK gene rearrangements as markers to detect clonal B cell populations in paraffin embedded sections. Family specific VH and VK primers are used in separate reactions together with the corresponding J primers to amplify rearranged VH and VK genes from genomic DNA. This allows to distinguish clonal from polyclonal B cell populations in most of the cases. The method may be helpful in routine diagnosis of B cell NHL and some morphological and immunohistochemical difficult cases.

Base Sequence↗
PubMed1992

Adolescent sexuality and issues in contraception.

The influence of physiologic, psychologic, and cultural influences on human sexuality is reviewed. These factors are considered in the exploration of how adolescents express their sexuality and the consequences of that expression.

Adolescent↗
PubMed1991

Neuronal activity and tonotopy in the auditory system visualized by c-fos gene expression.

Responsiveness in the cochlear nucleus complex and inferior colliculus of the mouse to tonal stimulation is labelled via immunocytochemically stained Fos protein that is expressed by c-fos gene activation in excited neurons. The locations of Fos-positive neurons closely reproduce the tonotopic maps in the dorsal cochlear nucleus and inferior colliculus. Thus, the c-fos method can demonstrate stimulus-related local neuronal activation on a single-cell level and may be useful to complement other mapping techniques such as electrophysiological recording or 2-deoxyglucose autoradiography.

Acoustic Stimulation↗
PubMed1991

Staphylococcal phosphoenolpyruvate-dependent phosphotransferase system. Purification and protein sequencing of the Staphylococcus carnosus histidine-containing protein, and cloning and DNA sequencing of the ptsH gene.

The histidine-containing protein (HPr) of the bacterial phosphoenolpyruvate-dependent phosphotransferase system (PTS) was isolated from Staphylococcus carnosus and purified to homogeneity. The protein sequence was determined by Edman degradation of peptides obtained by proteolytic digestion with proteases V8, trypsin and chemical cleavage with BrCN. Furthermore, immunological screening of a chromosomal S. carnosus DNA gene library in pUC19 vector enabled us to isolate S. carnosus HPr-expressing colonies. The nucleotide sequence of this ptsH gene and its flanking regions was determined by the dideoxy-chain-termination technique. Upstream, the 264-bp open reading frame of the ptsH gene is flanked by a putative S. carnosus promoter structure and a putative ptsI gene downstream suggesting that ptsH gene is the first gene in the PTS operon of S. carnosus. Comparison of the amino acid sequence of S. carnosus HPr with the HPr sequence of Staphylococcus aureus (derived from peptide sequencing) showed a high degree of similarity.

Amino Acid Sequence↗
PubMed1991

Cloning of PI3 kinase-associated p85 utilizing a novel method for expression/cloning of target proteins for receptor tyrosine kinases.

A novel method has been developed to allow cloning of protein targets for receptors with tyrosine kinase activity. By utilizing the carboxy-terminal tail of EGF receptor (EGFR) as a probe to screen lambda gt11 expression libraries, several EGFR-binding proteins have been cloned; two have been analyzed and contain unique SH2 and SH3 domains. One gene (GRB-1) has been fully sequenced, is expressed in various tissues and cell lines, and has a molecular mass of 85 kd. Interestingly, GRB-1 encodes the human counterpart of the PI3 kinase-associated protein p85. Advantages of this technique include the ease of cloning tyrosine kinase receptor targets present at low levels and the ability to identify proteins that are related in their capacity to bind activated receptors but contain no significant DNA sequence homology. This method, termed CORT (for cloning of receptor targets), offers a general approach for the identification and cloning of various receptor targets.

Amino Acid Sequence↗