Günther K. Bonn

Clinical Relevance of CDH1 and CDH13 DNA-Methylation in Serum of Cervical Cancer Patients

This study was designed to investigate the DNA-methylation status of E-cadherin (CDH1) and H-cadherin (CDH13) in serum samples of cervical cancer patients and control patients with no malignant diseases and to evaluate the clinical utility of these markers. DNA-methylation status of CDH1 and CDH13 was analyzed by means of MethyLight-technology in serum samples from 49 cervical cancer patients and 40 patients with diseases other than cancer. To compare this methylation analysis with another technique, we analyzed the samples with a denaturing high performance liquid chromatography (DHPLC) PCR-method. The specificity and sensitivity of CDH1 DNA-methylation measured by MethyLight was 75% and 55%, and for CDH13 DNA-methylation 95% and 10%. We identified a specificity of 92.5% and a sensitivity of only 27% for the CDH1 DHPLC-PCR analysis. Multivariate analysis showed that serum CDH1 methylation-positive patients had a 7.8-fold risk for death (95% CI: 2.2–27.7; p = 0.001) and a 92.8-fold risk for relapse (95% CI: 3.9–2207.1; p = 0.005). We concluded that the serological detection of CDH1 and CDH13 DNA-hypermethylation is not an ideal diagnostic tool due to low diagnostic specificity and sensitivity. However, it was validated that CDH1 methylation analysis in serum samples may be of potential use as a prognostic marker for cervical cancer patients.

Near infrared spectroscopy, cluster and multivariate analysis - Characterisation of silica materials for liquid chromatography

Near infrared (NIR) reflectance spectroscopy is a well established method within the analytical chemistry and a wide range of applications, for example in the field of food and pharmaceutical products, is covered. In the era of material science and nano technology, we brought together, in this feasibility study, silica chemistry with NIR. NIR, in the fibre-optics mode, is used for morphological studies. It enables differentiation between silica materials in a three-dimensional factor-plot depending on their functionalisation and physical properties such as particle diameter and pore diameter with Q-values of 0.95 and 0.99. The well established, common reference methods for the determination of surface area and porosity are the so called Brunnauer Emmett Teller method and size-exclusion chromatography. Both methods are time-consuming and require a lot of experience. The recently elaborated NIR method offers a physicochemical quantitative description at the nano-scale level of particle size, specific surface area, pore diameter, pore porosity, pore volume and total porosity with high linearity of R2 > 0.97 for calibration and r2 > 0.98 for validation and a bias of < 2.48 × 10−14. Compared to the reference method, which enables the determination of the individual parameters with a relative standard deviation between 6 and 28%, the NIR method shows RSD% between only 0.010 and 13.7%, which means a fundamental improvevement in precision. The measurement takes only a few seconds so high sample throughput is guaranteed. The suitability of the newly established method in material science is demonstrated, as an example, on the silica stationary phases for liquid chromatography.

Mass spectrometric profiling of low-molecular-weight proteins.

Tracing potential biomarkers through proteomics has been further developed and is nearing realization. The whole sequence of human proteome is becoming better understood with the passage of time. However, it is a long way to go to pinpoint biomarker proteins out of complex biofluids and use them for clinical diagnosis, prognosis, and therapeutic applications. From that point of view, the high hopes put in proteomics have not been fulfilled yet. The key reasons for that is the complexity of the proteome and the limited technologies in terms of specificity and reproducibility. Thus, major focus is put on the development of novel innovative analytical techniques in the field of life science, using high-performance single- and multidimensional separation and enrichment methods, such as solid-phase extraction (SPE), liquid chromatography (HPLC), or capillary electrophoresis (CE) coupled to mass spectrometry (MS). A newly emerged technology, termed as material-enhanced laser desorption/ionization (MELDI) meets basic requirements and is applied to reduce the complexity of proteomic samples while liquid chromatography (LC) is used for separation and fractionation, followed by identification with MS/MS including database searching analysis. Different MELDI carriers are employed as support materials to specifically bind peptides and proteins from biofluids like serum or urine. The MELDI approach supports automated routine analysis by means of liquid handling robots for high-throughput applications leading to higher reproducibility, crucial for a successful identification of disease markers with MALDI-TOF MS. Such promising new methods and further technical developments will be necessary to answer the high-wrought expectations on the field of proteomics.