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Biomedical subjects

Michael Fleischhacker

Publications and source records attributed to Michael Fleischhacker.

6 recordsLinked to original sources
PubMed2004

Quantification of free RNA in serum and bronchial lavage: a new diagnostic tool in lung cancer detection?

Circulating cell-free nucleic acids have been detected in serum. In cancer patients levels of free DNA seem to be higher than in non-tumor controls and the detectable nucleic acids are partly of tumor origin. We asked whether free RNA can be detected as well in cell-free bronchial lavage fluid (BLF) supernatant, and whether quantification of free RNA allows to discriminate between tumor and non-tumor patients. 73 patients with lung cancer (NSCLC n=62, SCLC n=11) and 56 patients with non-malignant lung diseases were included. The RNA was isolated from 1 mL serum and lavage, respectively with the Quiamp MinElute Virus Vacuum Kit (Qiagen, Germany). A real-time quantitative RT-PCR assay was used for transcript quantification of the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene. Intact RNA was detectable in cell-free supernatants of BLF from 126/129 patients and was investigated in all 64 serum samples. RNA levels were higher in the cell-free supernatant of BLF than in serum. RNA concentration in the BLF from tumor patients was higher than in patients with a benign lung disease (p=0.009). In conclusion, quantification of intact RNA isolated from BLF supernatant and from serum might become a valuable tool for differentiation between tumor and non-tumor patients.

Adult↗
PubMed2004

TP53 gene in blood plasma DNA of tumor patients.

Tumor-specific TP53 mutations are detectable in the blood plasma of tumor patients. Mutations of the TP53 tumor suppressor gene are risk factors for tumor progression. The objective of this work is to compare the presence of TP53 mutations in plasma-DNA before and after tumor treatment with the status of this gene in the tumor tissue sample. DNA was extracted from plasma samples of 25 patients with gastrointestinal tumors, and from paraffin-embedded tumor tissues from the same patients. Temperature gradient gel electrophoresis (TGGE) was performed for mutation screening of exons 5-8 of GC-clamped polymerase chain reaction products. Mutation-positive and wildtype gel bands from TGGE were cut and reamplified for fluorescence-labeled sequence analysis. The results of several mutation analyses were correlated with analysis of p53 autoantibodies in the same plasma. Mutation frequency (one or several mutations per sample) was 7.1% in blood plasma of tumor-free patients, 87.0% in tumor tissues, 78.6% in plasma before tumor treatment, and 36.8% after treatment. Fifteen of 22 mutations in tumor tissues of 13 patients also were detected in the same exons of plasma before treatment (68.2%). Mutations in plasma after treatment (2-684 days) were the same in 6 of 30 cases of tissue mutations only. Six of seven patients with mutations after treatment in their plasma had metastases. One patient was p53 autoantibody negative, but has a terminator mutation of codon 196 in tissue and in posttreatment plasma as well. Genetic analysis of plasma in tumor patients should be further developed, as it might be of prognostic value.

Autoantibodies↗
PubMed2004

Detection of cell-free DNA in bronchial lavage fluid supernatants of patients with lung cancer.

Recently, it was shown that it is possible to isolate free circulating DNA from plasma/serum of patients with benign and malignant diseases. In addition, several groups were able to detect tumor-associated alterations in these nucleic acids. We wondered whether any nucleic acids are detectable in cell-free bronchial lavage supernatants, which until now have been discarded after cell harvest. Additionally, we wanted to find out if it is possible to detect tumor-associated alterations in these DNA molecules. DNA was isolated from cell-free lavage supernatants from 30 lung cancer patients, and the DNA was examined for microsatellite alterations. Intact DNA could be isolated from all cell-free bronchial lavage supernatants. Microsatellite alterations were found in lavage supernatants of 12 of 30 patients and in lavage cells of 6 of 30 patients. Altogether, alterations were found in 14 of 30 patients. Thus, we could demonstrate for the first time that it is possible to isolate intact DNA from cell-free bronchial lavage supernatants. Their quantity and quality are sufficient for further amplification via polymerase chain reaction. Altogether, tumor-associated changes were detected in the DNA of 47% of the patients that were analyzed.

Aged↗
PubMed2003

Microsatellite alterations in free-circulating serum DNA in patients with ulcerative colitis.

BACKGROUND/AIMS: The aim of this study was to find out whether there is free-circulating DNA in the serum of patients with ulcerative colitis and whether it is possible to establish a panel of genetic alterations which might be useful markers for diagnostic purposes, staging, or follow up. METHODS: A set of 11 microsatellite markers located on different chromosomes were analyzed in a group of 59 patients with ulcerative colitis. Radiolabeled PCR products from serum and white blood cell DNA were analyzed by autoradiography and correlated with the clinical data from these patients. RESULTS: Seven of 59 patients showed one or more microsatellite alteration(s) in their serum DNA. Six patients had an alteration in one marker, and two patients had changes in 4 markers, respectively. There was no correlation between the frequency of microsatellite alterations and the clinical data. CONCLUSION: From the panel of 11 microsatellite markers used for these studies, 6 of them seem to be well suited for the detection of ulcerative colitis-associated alterations in free circulating serum DNA. In order to increase the specificity of this assay, it is necessary to increase the number of patients to be analyzed and to use a different set of markers.

Biomarkers↗