Showing papers by "Hans J. Tanke published in 1989"
TL;DR: In a blind study, chromosome aberrations in tumor cells were analyzed by conventional cytogenetic techniques (G banding) and nonradioactive in situ hybridization with chromosome-specific probes and gave reliable results and allowed detection of cell subpopulations that were not detected by analyzing metaphase chromosomes.
127 citations
TL;DR: The application of light microscopy in medicine and cell biology has been significantly influenced by both the availability of specific biological reagents such as monoclonal antibodies and nucleic acid probes as well as by the enormous progress in microelectronics and computer technology.
Abstract: SUMMARY
The application of light microscopy in medicine and cell biology has been significantly influenced by both the availability of specific biological reagents such as monoclonal antibodies and nucleic acid probes, as well as by the enormous progress in microelectronics and computer technology. It is likely that specific reagents for a variety of cellular macromolecules will become available on a large scale in the coming years. Moreover, methods using both sensitive detection devices such as charge-coupled device (CCD) cameras and sophisticated image processing exist to quantify this information at the single molecule level in morphologically intact cells.
This paper describes the impact of these two factors on the light microscope of the future, with special emphasis on fluorescence. It defines the improvements that still are required to solve some of the challenging problems such as the quantification of unique genes and their products in intact cells, the quantification of DNA adducts and the detection of rare mutant cells or circulating tumour cells.
34 citations
01 Jan 1989
TL;DR: Flow cytometry represents a relatively new technique that has been developed for the quantitative analysis of individual cells and cellular constituents and is commonly fluorescently stained, although non-fluorescing dyes in sufficient concentration can be measured as well on the basis of axial light absorption.
Abstract: Flow cytometry represents a relatively new technique that has been developed for the quantitative analysis of individual cells and cellular constituents. The principle of flow cytometry is that cells or cellular components in aqueous suspension are passed through a sensing region where optical or electrical signals are generated and measured. The typical analysis rate of commercial instruments is in the order of several thousand objects per second. Cells are generally fluorescently stained, although non-fluorescing dyes in sufficient concentration can be measured as well on the basis of axial light absorption. Staining is not required for measurements of cell size by light scatter or electrical resistance. The reproducibility of fluorescence measurements is 2% or better, and the detection limit of most commercial instruments is 2000–3000 molecules of fluorescein per cell. A schematic representation of a typical flow cytometer is seen in Figure 1. The cells are hydrodynamically forced with a constant speed of 5–10 m/sec to a region onto which a high intensity light source, usually a laser or high pressure arc lamp, is focussed to generate light scatter signals and fluorescence emission. Properly oriented photodetectors collect a fraction of the signals and generate electrical signals proportional to the optical signals.