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Biomedical subjects

Thomas Metz

Publications and source records attributed to Thomas Metz.

7 recordsLinked to original sources
PubMed2006

Correlation of ErbB2 gene status, mRNA and protein expression in a panel of >100 human tumor xenografts of different origin.

INTRODUCTION: The receptor tyrosine kinase ErbB2 is an important prognostic marker and therapeutic target in breast cancer. The aim of this study was to investigate the correlation between ErbB2 gene amplification, mRNA and protein expression in a panel of >100 patient-derived nude mouse tumor xenografts of different histological origin. MATERIALS AND METHODS: Data were obtained using fluorescence in situ hybridization, GenChip expression analysis, immunohistochemistry and enzyme-linked immunosorbent assay (ELISA). Tumors included the following types: urinary bladder, breast, colon, stomach, kidney, liver, lung, melanoma, ovary, pancreas, prostate, uterus/cervix uteri and others. RESULTS: All tumors with high-level ErbB2 gene amplification expressed ErbB2 mRNA at a level >10-fold above average and protein at a level >20-fold above average (ELISA). Correlation was found between ErbB2 mRNA and protein expression. CONCLUSION: Based on expression data, cervical, gastric and adenocarcinomas of the lung emerged as new potential indications for ErbB2-directed cancer therapies.

Biomarkers, Tumor↗
PubMed2006

Generation Challenge Programme (GCP): standards for crop data.

The Generation Challenge Programme (GCP) is an international research consortium striving to apply molecular biological advances to crop improvement for developing countries. Central to its activities is the creation of a next generation global crop information platform and network to share genetic resources, genomics, and crop improvement information. This system is being designed based on a comprehensive scientific domain object model and associated shared ontology. This model covers germplasm, genotype, phenotype, functional genomics, and geographical information data types needed in GCP research. This paper provides an overview of this modeling effort.

Crops, Agricultural↗
PubMed2004

Absorption of formaldehyde (H2CO) in the A1A2 <-- X1A1 band system at elevated temperatures and pressures.

The electronic A1A2 <-- X1A1 absorption spectra of formaldehyde vapour were studied at temperatures varying from 423 to 770 K with variable pressures from less than 0.1 to 1 MPa. Broadband vibronic and partially rotationally resolved 4(0)(1) rovibronic spectra of formaldehyde showed considerable sensitivity to temperature. The high resolution spectra showed collision-induced broadening as the pressure was increased. The results show that the absorption efficiency of the laser radiation from the third harmonic of Nd:YAG lasers is sensitive to the spectral properties of the laser, such as line position and shape. Promising results were obtained from the comparison between theoretical and measured absorption spectra.

Absorption↗
PubMed2004

Fluorescence lifetimes of formaldehyde (H2CO) in the A1A2 --> X1A2 band system at elevated temperatures and pressures.

Fluorescence lifetimes of formaldehyde excited by picosecond laser radiation with a wavelength of 355 nm were determined in nitrogen gas in a cell using time-resolved laser-induced fluorescence spectroscopy. The measurements were conducted at temperatures between 295 and 770 K and pressures up to 10 bar (1 MPa). Detection was broadband in most cases. Temperature and pressure were found to have a quenching effect on the fluorescence. At 295 K and pressures between 1 and 5 bar, decay rates between 0.03 and 0.04 ns(-1) were observed. At 770 K, the decay rates increased from 0.11 to 0.17 ns(-1) as the pressure was raised from 1 to 10 bar. The dependence on pressure was not linear at 1 bar. At 10 bar the linearity is unclear. The dependence on temperature appeared to be exponential.

Formaldehyde↗
PubMed2003

Autonomous detection of aerosolized Bacillus anthracis and Yersinia pestis.

We have developed and tested a fully autonomous pathogen detection system (APDS) capable of continuously monitoring the environment for airborne biological threat agents. The system is designed to provide early warning to civilians in the event of a terrorist attack. The final APDS will be completely automated, offering aerosol sampling, in-line sample preparation fluidics, multiplexed detection and identification immunoassays, and orthogonal, multiplexed PCR (nucleic acid) amplification and detection. The system performance (current capabilities include aerosol collection, multiplexed immunoassays, sample archiving, data reporting, and alarming) was evaluated in a field test conducted in a Biosafety Level 3 facility, where the system was challenged with, and detected, a series of aerosolized releases containing two live, virulent biological threat agents (Bacillus anthracis and Yersinia pestis). Results presented here represent the first autonomous, simultaneous measurement of these agents.

Aerosols↗
PubMed2003

Maximum-likelihood curve-fitting scheme for experiments with pulsed lasers subject to intensity fluctuations.

Evaluation schemes, e.g., least-squares fitting, are not generally applicable to any types of experiments. If the evaluation schemes were not derived from a measurement model that properly described the experiment to be evaluated, poorer precision or accuracy than attainable from the measured data could result. We outline ways in which statistical data evaluation schemes should be derived for all types of experiment, and we demonstrate them for laser-spectroscopic experiments, in which pulse-to-pulse fluctuations of the laser power cause correlated variations of laser intensity and generated signal intensity. The method of maximum likelihood is demonstrated in the derivation of an appropriate fitting scheme for this type of experiment. Statistical data evaluation contains the following steps. First, one has to provide a measurement model that considers statistical variation of all enclosed variables. Second, an evaluation scheme applicable to this particular model has to be derived or provided. Third, the scheme has to be characterized in terms of accuracy and precision. A criterion for accepting an evaluation scheme is that it have accuracy and precision as close as possible to the theoretical limit. The fitting scheme derived for experiments with pulsed lasers is compared to well-established schemes in terms of fitting power and rational functions. The precision is found to be as much as three timesbetter than for simple least-squares fitting. Our scheme also suppresses the bias on the estimated model parameters that other methods may exhibit if they are applied in an uncritical fashion. We focus on experiments in nonlinear spectroscopy, but the fitting scheme derived is applicable in many scientific disciplines.

Journal Article↗