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Biomedical subjects

A Götze

Publications and source records attributed to A Götze.

15 recordsLinked to original sources
PubMed2002

[Improving SNR (signal to noise ratio) in multichannel EEG recording].

The main problem in measurements of the focal VEP (Visual Evoked Potential) is its weak SNR (Signal-to-Noise Ratio). The most common method for enhancement of the SNR is the stimulus synchronized averaging. For study of single responses other ways in SNR improvement are needed. In this contribution a new method based on space-time selective measurement is introduced, which can be interpreted as beaming a signal source. Since the anatomical structures of sources generating the focal VEP are known in general and if the electrode positions are of sufficient density over the visual cortex, a source beamer can be realized by controlling the channels' delays.

Algorithms↗
PubMed2000

Human dendritic cells transfected with either RNA or DNA encoding influenza matrix protein M1 differ in their ability to stimulate cytotoxic T lymphocytes.

The use of tumor antigen loaded dendritic cells (DC) is one of the most promising approaches to induce a tumor specific immune response in vivo. Several strategies have been designed to load DC with tumor antigens. In this study, we investigated the delivery of in vitro transcribed RNA and plasmid DNA into monocyte-derived, ie non-proliferating human DC, using several nonviral transfection methods including electroporation and lipofection. Green fluorescent protein (GFP) was used as a reporter gene and influenza matrix protein 1 (M1) as a model antigen for HLA class I restricted antigen presentation. Using electroporation in combination with DNA or with RNA, up to 11% of DC were GFP-positive. Using liposomes as a vehicle for DNA transport up to 10% of the DC were GFP-positive. A significant increase in transfection efficacy, of up to 20%, was observed when GFP RNA was used in combination with liposomes. Importantly, the RNA transfected DC retained their typical morphological and immunophenotypical characteristics. In addition, DC transfected with M1 RNA were able to stimulate autologous peripheral M1-specific memory cytotoxic T lymphocytes (CTL), as well as M1-specific CTL clones. Furthermore, comparison of DNA-transfected DC with RNA-transfected DC revealed the latter to be far better stimulators of antigen-specific T cells. This RNA transfection technique consequently represents a very promising tool for future immunotherapy strategies.

Antigens, Viral↗
PubMed1999

Chromosomal aberrations in humans as genetic endpoints to assess the impact of pollution.

The chromosomal aberration assay with peripheral blood lymphocytes has been used routinely during the last three decades to survey exposure of humans to various genotoxic agents. A large number of biomonitoring studies are based on this genetic endpoint. A great deal of data exists on occupational, life-style or medical exposure situations but less evidence of the validity of the assay is available with regards to environmental exposure. In the present paper we report our investigations on the impact of pollution in two different populations using chromosomal aberrations in human peripheral blood lymphocytes as a biomarker of chronic exposure to heavy metals and dioxins/furans for a long period and as a biomarker of acute exposure to accidentally released vinyl chloride in the air. In order to study genotoxic effects (chromosomal aberrations) of heavy metals and dioxins/furans, 52 exposed individuals from a polluted area were compared to 51 matched controls from a distant non-industrialized area. A statistically significant increase was observed in the frequency of chromosomal aberrations in peripheral blood lymphocytes from the exposed population (1.90% aberrant cells vs. 1.11% for the controls). In the case of the vinyl chloride accident, chromosomal aberrations were analyzed in peripheral blood lymphocytes from 29 potentially exposed and 29 non-exposed individuals (matched controls). The exposed group showed a statistically significant increase in the frequency of aberrant cells (1.47% vs. 1.07% for the controls).

Accidents, Occupational↗
PubMed1999

Mosaic tetrasomy 9p in a girl with multiple congenital anomalies: cytogenetic and molecular-cytogenetic studies.

We report on a 16-year-old girl with tetrasomy 9p mosaicism. Clinical investigations disclosed a malformation syndrome with craniofacial abnormalities, dysplasia of the right clavicle, short neck with cervical ribs, patella dislocation, Dandy-Walker malformation, mental retardation and blindness. Karyotype analysis of blood lymphocytes indicated an additional marker in the size of a C-group chromosome with a large heterochromatic block in 88% of the investigated metaphases. The origin and structure of this additional marker could not be determined by chromosome banding. Application of fluorescence in situ hybridisation and comparative genomic hybridisation identified the origin of the marker chromosome, demonstrating the effectiveness of molecular-cytogenetic investigations in the diagnosis of structural and numerical chromosome abnormalities.

Abnormalities, Multiple↗
PubMed1984

Isomeric N-methyl-7-deazaguanines: synthesis, structural assignment, and inhibitory activity on xanthine oxidase.

The N-methyl isomers of 2-amino-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-one (2a) have been synthesized regiospecifically and their structures assigned. The 3-methyl compound 3 was obtained by alkylation of the parent chromophore 2a with dimethyl sulfate, and the 1-methyl isomer 5b was obtained by condensation of ethyl 2-cyano-4,4-diethoxybutyrate with N-methylguanidine and subsequent cyclization. Methylation of 2-amino-4-chloro-7H-pyrrolo[2,3-d]pyrimidine (7b), however, with methyl iodide in the presence of 50% NaOH, by phase-transfer techniques, followed by the replacement of halide by hydroxyl, yielded the 7-methyl compound 2b. The N-methyl isomers of 2a were all found to be inhibitors of xanthine oxidase from cow's milk. While the 3-methyl isomer 3 exhibits a Ki of 40 microM, the 7- and 1-isomers show Ki values of 4.5 and 3 microM, respectively.

Guanine↗
PubMed1983

[Staphylococcus epidermidis as a rare cause of sepsis].

Implanted synthetic materials have to be included into the differential diagnosis of sepsis. This paper reports on a case of sepsis caused by Staphylococcus epidermidis in connection with a Spitz-Holter shunt. The interval between the implantation and the recognition of the endoplastitis took 4 years. The attempt of an antibiotic sanitation had no results. The fitness for work could be restored by removal of the shunt and reimplantation.

Adult↗