Biomedical subjects

Ewald Wöll

Publications and source records attributed to Ewald Wöll.

6 recordsLinked to original sources

PubMed2003

Characterisation and predictive value of epidermal growth factor receptor status using quantitative real-time PCR combined with immunohistochemistry on non-small cell lung cancer specimens.

The frequency of increased EGFR-mRNA expression was determined in 57 patients suffering from NSCLC by applying quantitative real-time PCR. The findings were correlated with clinical parameters and the immunohistochemical (IHC) markers EGFR, c-erbB-2, c-erbB-3, Ki-67 and p53 on cryostat sections. Of the patients 46% showed increased EGFR-mRNA, 35% revealed an increased IHC-EGFR expression; 16% of the patients showed a combined positivity and 35% a combined negativity when applying both methods, and 17 (30%) of the cases revealed increased EGFR-mRNA without IHC-EGFR expression. This subgroup was characterised by p53 coexpression and the highest frequency of deaths (35% vs. 20%) indicating a more aggressive tumour type. In contrast to IHC - where positivity was seen predominantly in squamous cell carcinomas (48% vs. 27%) - EGFR-mRNA expression was observed equally in both histological subtypes (48% vs. 43%). PCR-EGFR and IHC-EGFR tumour typing identifies different tumour characteristics with different clinical courses. Whether this combined typing could help to identify patients who respond to anti-EGFR therapies is worth further testing.

Carcinoma, Non-Small-Cell Lung↗

PubMed2003

Automated real-time PCR to determine K-ras codon 12 mutations in non-small cell lung cancer: comparison with immunohistochemistry and clinico-pathological features.

A real-time PCR technique with automated computerized analysis (TaqMan ) was tested to detect K-ras mutations in 66 patients suffering from NSCLC. This technology is characterized by high reproducibility of data and a time-saving analysis procedure. In 11% (7/66) of the tumour specimens and 2% (1/58) of adjacent tumour-free lung specimens a K-ras codon 12 mutation was detected. In adenocarcinomas containing > or =40% tumour cells, however, K-ras mutations were seen in 25% of the cases. The point mutations detected in tumours were GGT right curved arrow TGT in five cases and GGT right curved arrow GTT in two cases. As compared with immunohistochemical parameters, the K-ras mutated group was characterized by a c-erbB-2 negativity (p=0.04) and a smaller number of c-erbB-3 (p=0.02) positive cases. EGFR, bcl-2, p53, Ki-67 and p120 expression did not differ significantly. Determination of the K-ras point mutations by automated TaqMan PCR in NSCLC tumour specimens is feasable and highly specific. Due to its high throughput capacity this method represents a valuable tool for routine screening.

Carcinoma, Non-Small-Cell Lung↗

PubMed2002

Transendothelial migration of leukocytes and signalling mechanisms in response to the neuropeptide secretoneurin.

Secretoneurin (SN), a newly discovered neuropeptide, may be implicated in inflammatory responses as it was shown to modulate leukocyte, endothelial and mesenchymal cell functions. Neutrophils placed above pulmonary arterial or venous endothelial monolayers migrated through this cellular barrier in response to apical or basal stimulation with SN in a dose-dependent manner. At optimal concentrations of 10(-6) to 10(-8) M, SN was nearly equally effective in stimulating neutrophil transmigration as was tumor necrosis factor-alpha at 10 ng/ml or a chemotactic gradient of formyl-Met-Leu-Phe (10(-8) M). Stimulation of transendothelial migration appears to be specific, since a trypsin digest of SN was ineffective and excess concentrations of anti-SN antibodies completely abolished the effect. Inhibition of cyclooxygenase or nitric oxide synthase did not affect the action of SN. Preincubation of endothelial cells with pertussistoxin (PTx) or choleratoxin (CTx), and the presence of staurosporine significantly inhibited transmigration, suggesting that SN uses a signalling pathway that is coupled to G-proteins and protein kinase C in endothelium. Moreover, SN treatment resulted in transient elevation of cytoplasmatic calcium concentration in endothelial cells. These data support the hypothesis that SN might contribute to neurogenic inflammation in vivo and reveal signalling mechanisms of SN in endothelial cells.

Animals↗

PubMed2002

Simvastatin inhibits malignant transformation following expression of the Ha-ras oncogene in NIH 3T3 fibroblasts.

In previous studies we have shown that the expression of the transforming Ha-ras oncogene in NIH 3T3 fibroblasts stimulates cellular calcium entry, which triggers oscillatory calcium induced calcium release from internal stores. The intracellular calcium oscillations lead to cytoskeletal remodeling by actin stress fiber depolymerization and activation of the Na(+)/H(+) exchanger thus mediating cell swelling and intracellular alkalosis, both important mitogenic signals. This is evidenced by abrogation of Ha-ras induced growth factor independent cell proliferation by interference with any of these events, i.e. by inhibition of cellular calcium entry or inhibition of the Na(+)/H(+) exchanger. As shown in this study, simvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the key enzyme for cholesterol biosynthesis, is able to prevent these events following the expression of the transforming Ha-ras oncogene. We show, that simvastatin inhibits farnesylation dependent membrane translocation of a CAAX motive bearing yellow fluorescent protein and suppresses Ha-ras stimulated cellular calcium influx, which can be identified as capacitative calcium entry. In addition simvastatin is able to block regulatory volume decrease channels and to suppress the cytoskeletal remodeling, intracellular alkalinization, increase in cell volume and growth factor independent cell proliferation induced by the oncogene. Thus simvastatin is able to prevent crucial cellular events following expression of the transforming Ha-ras oncogene.

3T3 Cells↗

PubMed2002

Involvement of cyclic adenosine monophosphate-dependent protein kinase A and pertussis toxin-sensitive G proteins in the migratory response of human CD14+ mononuclear cells to katacalcin.

Katacalcin (KC) belongs to a small family of polypeptides that are encoded by the calc-1 gene and also include calcitonin (CT) and procalcitonin NH2-terminal cleavage peptide (N-ProCT). Biological roles of KC or N-ProCT are unknown. To determine whether these polypeptides affect leukocyte function, forearm venous blood polymorphonuclear neutrophils and CD14+ peripheral blood mononuclear cells (PBMCs) were isolated from healthy human donors. Cell migration was assessed in a blindwell chemotaxis chamber using nitrocellulose micropore filters. Cellular levels of cyclic adenosine monophosphate (cAMP) were measured by HPLC; activation of protein kinase A was studied by Western blot. Fluorochrome-labeled peptide binding to cells was studied by fluorescence-activated cell sorting (FACS) and intracellular calcium transients were studied by confocal microscopy with FLUO-3. KC elicited concentration-dependent migration of CD14+ PBMC at concentrations from the atomolar to the micromolar range and deactivated attractant-induced chemotaxis. CT N-terminal flanking peptide had no such effect. Neutrophils did not migrate toward any of those peptides and their oxygen-free radical release was not affected as measured fluorometrically. Functional responses of CD14+ PBMC to KC correlated to forskolin-sensitive cAMP accumulation in cells and were inhibited by protein kinase A inhibitor (PKI) and Rp diastereomer of adenosine 3',5'-cyclic monophosphorothioate. Treatment of CD14+ PBMC with KC activated protein kinase A(C alpha). Intracellular calcium was decreased with CT, KC, and procalcitonin (PCT). Binding studies showed that KC might share the binding site with CT and PCT. Data indicate that KC regulates human CD14+ PBMC migration via signaling events involving protein kinase A-dependent cAMP pathways.

Adult↗

PubMedDate not supplied

Comparison of automated cellular imaging system and manual microscopy for immunohistochemically stained cryostat sections of lung cancer specimens applying p53, ki-67 and p120.

Seventy-one frozen lung tissue specimens from 52 patients suffering from non-small cell lung cancer (NSCLC) were analysed in this study. Cryostat sections were stained with monoclonal antibodies against p53, ki-67 and p120, all of which are of prognostic value in NSCLC. Slides were evaluated by standard manual microscopy (MM) and using a new Automated Cellular Imaging System (ACIS). The results obtained with ACIS correlated significantly with MM examination (p<0.001). However, ACIS showed a higher sensitivity, especially for specimens with a low infiltration volume. In 15 (6.8%) MM negative cases singular positive cells were identified with ACIS. In cases with a high infiltration volume subjective (MM) quantitation tended to overestimate the number of infiltrating cells. ACIS guaranteed a high reproducibility of data. We conclude that ACIS-assisted analysis is a valid means of investigating the p53, ki-67 and p120 antibody expression in cryostat sections of lung cancer specimens. ACIS can complement conventional manual microscopy due to its higher accuracy, sensitivity and better reproducibility of data.

Adenocarcinoma↗