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Biomedical subjects

H Stein

Publications and source records attributed to H Stein.

At least 199 records · Page 11Linked to original sources
PubMed1997

Uniform expression of cytotoxic molecules in anaplastic large cell lymphoma of null/T cell phenotype and in cell lines derived from anaplastic large cell lymphoma.

We recently provided ample evidence that anaplastic large cell lymphomas of T/null phenotype (T-/null-ALCL) genotypically represent peripheral T cell lymphomas which in up to 90% have a phenotype of cytotoxic cells with expression of granzyme B protein and perforin transcripts. However, the issue of granzyme B expression in T-/null-ALCL is still controversial due to differing results from another laboratory. To verify our earlier immunohistochemical stainings for granzyme B, we looked for granzyme B transcripts by in situ hybridization (ISH). In addition, we investigated our previously analyzed cases by immunohistology (IH) with another antibody (2G9), which reacts with two molecules known to be expressed in cytotoxic cells: T-cell-restricted intracellular antigen (TIA)-1 and granule membrane protein-17 (GMP-17). We also extended our studies to homogenous tumor cell populations provided by ALCL-derived cell lines. As evidenced by ISH, transcripts for perforin, TIA-1 and granzyme B were found in all ALCL-derived cell lines. Similarly, proteins of TIA-1/GMP-17, granzyme B and perforin were expressed in all of these lines as shown by IH. In biopsy specimens, TIA-1/GMP-17 were detected by IH in 14/16 cases of T-/null-ALCL, and granzyme B transcripts were found in 13/13 T-/null-ALCL cases, but not in 6 B-ALCL cases. The detection of granzyme B transcripts yielded results largely identical to those of IH for granzyme B protein, thus confirming our earlier data and suggesting that the regulation of the expression of this molecule largely occurs at the transcriptional level. Our data further confirm the almost uniform expression of cytotoxic molecules in both primary ALCL cases and ALCL-derived cell lines and therefore suggest that the derivation from cytotoxic T cells may be the unifying characteristic for T-/null-ALCL.

Cytotoxicity, Immunologic↗
PubMed1997

Upregulation of CD40 and CD40 ligand expression in IgE-associated cutaneous diseases.

In order to better understand the immunological processes connected with IgE-associated cutaneous disease, we have examined the expression of CD40 and its ligand CD40L, required for the induction of IgE synthesis in B-cells, as well as of IgE and its receptors in various dermatoses (atopic dermatitis (AD), scabies, chronic recurrent urticaria) versus normal skin, and in one dermopathic lymph node versus normal lymphatic tissue by immunohistochemistry. Compared to normal skin, cells expressing IgE, Fc epsilon RI, Fc epsilon RII, CD40, CD40L and L26 were increased in the dermis, partly also in the epidermis, from patients with AD and scabies, but not in chronic urticaria. CD40 and CD40L were detected on numerous cells in lymphatic tissue from both normal donors and a patient with AD, whereas large numbers of IgE- and Fc epsilon RI-positive cells were only found in the dermopathic lymph node from the AD patient, in contrast to very few in normal lymphatic tissue. These results with selectively increased IgE/Fc epsilon RI and associated CD40/CD40L expression in the skin of AD and scabies suggest that cutaneous tissue, in addition to dermopathic lymphatic tissue, might contribute to IgE synthesis.

Antigen Presentation↗
PubMed1997

Cell kinetics, morphology, and molecular IgVH gene rearrangements in Hodgkin's disease.

The present study dealt with the question of whether any cellular kinetic patterns correlate with clonal rearrangement of the IgVH gene as revealed by polymerase chain reaction on DNA extracted from lymph nodes with classical Hodgkin's disease (HD) and/or from single CD30+ cells (Hodgkin [H] and Reed-Sternberg [RS] cells). In 15/4 cases with H-RS cells of B or Null phenotype, signs of such monoclonality could be detected (group I) but not in the others (group II). CD30+/H-RS cells in group I differed slightly but significantly from those in group II in that they a) exhibited a larger fraction of cells attaining the anaphase/telophase stage of mitosis, and b) produced relatively more mononucleated cells (H) at the expense of multinucleated (RS) cells. In addition, reactive lymphoid cell (CD30-) infiltrates were considerably less dense in group I that in group II. These findings suggest that the cytokinesis of H-RS cells in group I was moderately more efficient than in group II. However, signs of monoclonality were not associated with the normalization of the mitotic process, which also proved to be disturbed in group I.

Adolescent↗
PubMed1997

Frequent expression of the NPM-ALK chimeric fusion protein in anaplastic large-cell lymphoma, lympho-histiocytic type.

The revised European-American lymphoma classification recognizes a subtype of anaplastic large-cell lymphoma (ALCL), termed lympho-histiocytic because of its peculiar cytological composition. As in the case of classical ALCL, this tumor usually occurs in young patients and shows an excellent response to chemotherapy, but some authors have suggested that in reality this is a nonanaplastic T-cell lymphoma rich in histiocytes. In this paper, we show that three of five cases of lympho-histiocytic ALCL stain with anti-ALK antibodies and can therefore be presumed to express the chimeric NPM/ALK protein secondary to (2;5) translocation. These findings further support the inclusion of this as a type of ALCL and not among the nonanaplastic peripheral T-cell lymphomas. Furthermore, they indicate that staining for ALK proteins is a powerful tool for the diagnosis of lympho-histiocytic ALCL, the recognition of which may be difficult on morphological grounds.

Adolescent↗
PubMed1997

[Food hygiene aspects in the production of food fish in fishing].

The development of the aerob-mesophilic bacteria on epidermis and peritoneum of 68 barbels was determined at 0, 4 and 8 hours after slaughtering. Therefore, one group of 34 animals was stored at 15.3 degrees C, an other equal one at 21.6 degrees C. A change in germ counts per cm2 could be seen in none of the groups during the first 4 hours. However, unrefrigerated carcasses showed an increase of bacteria up to 5-fold between the 4th and 8th hour, whereas in the refrigerated group no change occurred during that time, too. Rinsing the fish after slaughtering resulted in a decrease of the initial bacterial counts by up to 65.4% and so in significantly lower germ loads at the end of the storage time. These results were confirmed by contaminating 24 rainbow trout with Salmonella Infantis artificially. The frequency of detection did not change in refrigerated fish over 8 hours, while nearly doubling in unrefrigerated ones. Moreover, it could be shown that a Salmonella-concentration of only 30 CFU per 100 ml water was sufficient for contaminating fish in detectable grades. The study leads to the conclusion that the storage of instantly slaughtered fish in a common thermobox with freezing elements is suited for preserving its microbiological status for at least 8 hours. The caging of living fish after capture, which must be regarded critically under the aspect of treating animals in a humane way, seems therefore unnecessary.

Animals↗
PubMed1997

Paraganglioma of the cauda equina with associated intramedullary cyst: MR findings.

The MR imaging features of a paraganglioma of the cauda equina with associated spinal cord cysts are presented. MR imaging showed the tumor to be isointense with the spinal cord on all pulse sequences and to enhance homogeneously. The intramedullary cysts had increased signal intensity on proton density- and T2-weighted images, and involved the cervical and thoracic regions.

Cauda Equina↗
PubMed1997

MUC2 gene suppression in human colorectal carcinomas and their metastases: in vitro evidence of the modulatory role of DNA methylation.

The development of the majority of colorectal carcinomas is associated with a diminished expression of the intestinal mucin MUC2 in the tumor cells. The significance and the mechanism of this alteration are not yet known. We sought to determine the molecular basis of this tumor-associated change and to investigate the extent to which it might also relate to metastases. MUC2 gene expression was compared in normal (N), carcinomatous (T), and metastatic tissues (M) from nine patients by immunohistochemistry, in situ hybridization, and Northern blotting. Immunohistochemistry and in situ hybridization showed consistently lower amounts of the expressed protein and mRNA in T and in M than in N; quantitative analysis by Northern blotting confirmed that the differences between MUC2 mRNA expression between N, T, and M were significant, the expression in metastases being less than 5% of that in the normal colonic tissue. The influence of DNA methylation as a possible regulatory mechanism of MUC2 gene expression was tested after the 5' and 3'-regions flanking the first exon of MUC2 were recovered from a genomic DNA library and used as probes in Southern blot. The DNA was isolated from colon carcinoma cell lines expressing MUC2 strongly (LS174T) or moderately (T84) and from that which was nonexpressing (Colo 205), and it was digested with the methylation-sensitive enzyme HpaII. The Southern blot patterns indicated that the increased methylation in the promoter region was concomitant with the decrease of MUC2 mRNA expression. Methylation of the promoter region ligated into a reporter vector suppressed the expression of the luciferase reporter gene in the three investigated cell lines. Furthermore, the expression of MUC2 gene was enhanced by treating the MUC2-expressing colon carcinoma cells with 5-aza-2'-deoxycytidine, a methylation-inhibiting agent. To our knowledge this is the first report to show that: (a) MUC2 gene is strongly suppressed in liver and lymph node metastases of colorectal carcinomas, and (b) suppression of MUC2 gene in colon carcinoma cells in vitro is associated with methylation of the promoter region.

Base Sequence↗
PubMed1997

[Molecules of regulated secretion are differentiation markers of neuroendocrine tumors].

Regulated secretory vesicles of neuroendocrine cells encompass two distinct types, i.e. hormone-storing large dense core vesicles (LDCV) and neuron-like small synaptic vesicles (SSVs). The membranes of the vesicles and the acceptor organelles contain proteins which are essential for targeted membrane fusion and protein transport (SNARE hypothesis). Membrane proteins of SSV analogues such as synaptophysin, synaptobrevin (v-SNARE) and synaptotagmin are key proteins of neurosecretion. The plasma membrane proteins syntaxin and SNAP25 (t-SNARE) are indispensible for this locking/fusion process. This study was done to identify the molecular components of LDCVs, SSV analogues and the SNARE-complex in neuroendocrine tumors. Immunohistochemical analysis using a panel of antibodies was done on file material from benign or low-grade malignant neuroendocrine tumors (n = 20) and high-grade malignant intermediate or small cell carcinomas (n = 27) of the gut, pancreas and lung. The statistical evaluation of our results indicate that the expression of all marker molecules of the regulated secretory pathway is significantly reduced in high-grade malignant carcinomas when compared to benign or low-grade malignant tumors. The reduction of the LDCV matrix protein chromogranin A and of the SSV membrane protein synaptobrevin is highly significant in high-grade malignant carcinomas, which may even loose these proteins. In contrast, the synthesis of synaptophysin and the t-SNARE-protein SNAP25 appears to be better maintained even in small cell carcinomas. We conclude that the immunohistochemical diagnosis of high-grade malignant neuroendocrine tumors should mainly be based on the identification of SSV- and SNARE-proteins, especially synaptophysin and SNAP25. These marker molecules of the regulated secretory pathway are valuable tools for the diagnosis and classification of neuroendocrine tumors and contribute to the understanding of cellular differentiation pathways.

Biomarkers↗
PubMed1997

[Telomerase as a tumor marker?].

The maintenance of the length of chromosomes (telomeres) is the prerequisite of unlimited malignant growth of cells. In normal cells the telomeres will be shortened by each cell division finally leading to cell senescence. Unlimited growing cells possess an enzyme, the telomerase, which is able to maintain the length of the telomeres by de novo synthesis of the telomeric repeats. In consequence the telomerase is detectable in nearly all malignant tumours and cell lines. However, in addition to malignant cells some type of non-malignant cells such as germ cells, activated lymphocytes and basal epithelial cells contain significant amounts of telomerase activity. Therefore, the detection of telomerase activity by extractive procedures such as TRAP assay is not sufficient to determine malignant nature of tissue samples.

Biomarkers, Tumor↗
PubMed1997

[Hodgkin's disease: a mystery is being solved].

The cell lineage derivation and type of proliferation (monoclonal versus polyclonal) of the atypical cells in Hodgkin's Disease (HD) has remained in question up until now. Immunophenotypic studies favoured a lymphoid origin. Molecular biological studies using DNA extracted from whole biopsy material provided inconsistent results, probably due to the rarity of the atypical cells in the affected tissue. Hence the molecular biological studies were extended to the analysis of isolated atypical cells. However, even these single cells studies yielded conflicting results. We therefore have improved the technique of single cell isolation from tissue sections and applied it to 25 cases of classical HD and 11 cases of lymphocyte predominant HD (LPHD). We investigated a total of 1,465 single atypical cells for rearranged Ig variable-region chain (V) genes. In all instances in which the single cell DNA lead to a PCR amplification product, these were found to contain identical rearranged V region genes. All of these V region gene sequences proved to be highly mutated. The coding capacity of the rearranged Ig genes was frequently disrupted in classical HD but rarely in LPHD. The V sequences of the latter histotype showed in addition intra-clonal diversity in the majority of patients whereas this was not seen in all but one case of classical HD. Additionally, in 10 to 20% of classical HD cases T-cell antigens and/or cytotoxic molecules could be demonstrated in the atypical cells. These results indicate that, a) the atypical cells of LPHD are a clonal population of neoplastic germinal centre B cells; b) the atypical cells from 80-90% of classical HD cases represent a clonal expansion of B cells which are related to germinal centre B cells or their progeny; and c) the atypical cells of 10-20% of classical HD may originate from T cells.

Antigens, CD↗
PubMed1997

Molecular biology of Hodgkin's disease.

The mist surrounding the origin and genesis of HRS cells of classical HD is beginning to dissipate. Molecular biological studies of classical HD at the single cell level strongly suggest that the HRS cells in the majority of cases represent a monoclonal outgrowth of late germinal centre B cells that have lost their capacity to express IG through crippling mutations introduced during the germinal centre reaction. Because of the expression of T cell antigens and/or cytotoxic molecules, the HRS cells of a minority of classical HD cases appear to originate from T cells. Under physiological conditions, B cells that are unable to express IG are eliminated by apoptosis. In most B cell derived classical HD cases, the HRS cells have lost their IG gene coding capacity through mutation and should therefore die of apoptosis. Since this usually does not happen, blockade of the apoptotic pathway may be a major event in the pathogenesis of B cell related classical HD. It is tempting to assume that viruses such as EBV, as well as regulator genes that normally monitor the human genome for damaged DNA, such as TP53, might be involved in the postulated hindrance of the apoptotic pathway, leading to the genesis of classical HRS cells.

Chromosome Aberrations↗
PubMed1996

Anaplastic large-cell lymphomas of T-cell and null-cell phenotype express cytotoxic molecules.

To further specify the cellular origin and nature of anaplastic large-cell lymphoma (ALCL) and its relationship to other lymphoid neoplasms, particularly Hodgkin's disease (HD), we investigated the presence of cytotoxic molecules in a large well-characterized series of these tumors. For expression of the cytotoxic molecules perforin and granzyme B, in situ hybridization (ISH) and immunohistology were used, respectively. Overall, 23 of 25 ALCLs of T/null phenotype and five (three mixed cellularity and two nodular sclerosis) of 57 HD cases showed the presence of perforin transcripts and/or granzyme B molecules in neoplastic cells. Polymerase chain reaction (PCR) analysis of ALCLs showed that most (10 of 11) cases of null-cell ALCL (null-ALCL) contained a clonal rearrangement of T-cell receptor beta-chain genes, as did T-cell ALCL (T-ALCL; 9 of 10 cases). However, both cytotoxic molecules and clonally rearranged T-cell receptor beta-chain genes were absent in seven of seven and eight of nine cases of B-cell ALCL (B-ALCL), respectively. These data show that all or nearly all T-ALCLs, irrespective of the clinical subform or the lack of T-cell-associated molecules, are derived from activated cytotoxic T cells. The same appears to be true for the neoplastic cells of rare HD cases. These findings indicate that T-ALCLs are different from B-ALCLs and the majority of HD cases, and suggest that some HD cases, especially those with T-cell antigen-positive tumor cells, may be closely related to T-ALCL, at least in terms of cellular origin.

Biomarkers↗
PubMed1996

Expression of Epstein-Barr virus-gene products in Burkitt's lymphoma in Northeast Brazil.

The Epstein-Barr Virus (EBV) is consistently found in tumor cells of Burkitt's lymphoma (BL) endemic in central Africa and malaria is considered a pathogenic cofactor. In contrast, fewer than 20% of BL cases occurring in Western countries are EBV-associated. We have investigated 54 BL cases from Bahia, a tropical region of Northeast Brazil, for expression of EBV gene products by in situ hybridization and immunohistology and performed typing of the EBV by polymerase chain reaction. Ten pediatric BL cases from Germany served as controls. New cases of malaria were not observed in the period and area of our study. Small nuclear EBV encoded transcripts, EBER, were found in tumor cells of 47 of 54 Brazilian cases (87%) but in only 2 of 10 German cases (20%). Type I latency of the EBV infection with absence of EBV-encoded proteins LMP1 and EBNA2 was found in 45 of 47 of the EBER-positive Brazilian cases. In two cases, occasional LMP1-containing tumor cells were found in the neighborhood of small Schistosoma mansoni granulomas and scars. BHLF1 transcripts associated with lytic EBV infection could be detected in few cells in 3 of the 40 EBER-positive Brazilian cases investigated. EBV type A was found in the majority of Brazilian BL cases (20 of 30 A-type, 7 of 30 B-type, and 3 of 30 not amplifiable). Our results indicate that the association of Bahian BL with EBV, but not the regional prevalence of malaria, is similar to endemic African BL. In two cases, type II latency was found in association with schistosomiasis, suggesting a role of this parasitosis in the induction of an EBV expression pattern that is unusual for BL. Because chronic schistosomiasis is associated with elevated Th2 cytokine expression resulting in reduced cell-mediated cytotoxicity, it seems possible that altered local immunity is responsible for this peculiar phenotype.

Adolescent↗
PubMed1996

Low frequency of p53 gene mutation and protein expression in mucinous colorectal carcinomas.

Immunohistochemical data indicate that the frequency of p53 protein overexpression is consistently lower in the mucinous than in the non-mucinous carcinomas of the breast, ovary, pancreas and colon. This peculiar immunohistochemical behavior of the mucinous phenotype could be due to the effect of large amounts of mucus on the staining or to an actual mutation frequency difference between mucinous and non-mucinous carcinomas. This question was investigated on a group of mucinous colorectal carcinomas. DNA was extracted from paraffin sections of 16 human mucinous colorectal carcinomas and the mutation frequency was determined by sequencing of p53 exons amplified in PCR. The expression of p53 protein was determined with the avidin-biotin complex-peroxidase staining procedure and CM-1 antiserum. Twenty-five percent of the tumors, exhibited p53 protein overexpression and in 31% a mutation was detected. Concordance between the two techniques was found in 69% of tumors. Overexpression without mutation was observed in 12% and mutation without overexpression in 19%. G:C --> A:T transitions represented the most frequent lesion (80%), as previously observed in non-mucinous colorectal carcinomas. These data indicate that the mutation pattern in the p53 gene is similar in mucinous and non-mucinous colorectal carcinomas. The low frequency of p53 overexpression in the mucinous phenotype is not due to a mucus effect on the staining but is related to the low mutation frequency of p53 gene. These results lead to the hypothesis that in contrast to the nonmucinous tumors the development of the majority of colonic carcinomas with the mucinous phenotype may be independent from p53 mutations.

Adenocarcinoma, Mucinous↗