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Biomedical subjects

L L Steinmetz

Publications and source records attributed to L L Steinmetz.

6 recordsLinked to original sources
PubMed1976

Flow microfluorometric analysis of sperm DNA content: effect of cell shape on the fluorescence distribution.

The DNA content of individual sperm from populations of acriflavine-stained cells was investigated by analysis of fluorescence frequency distributions obtained with high-resolution flow-systems instruments. Sperm with spherical or cylindrical heads from three mollusk species produce narrow, symmetric fluorescence distributions. Flat sperm heads from six eutherian species produce asymmetric distributions consisting of a peak with a lateral extension to higher fluorescence values. The unexpected shape of these distributions was shown to be due to the flat geometry and high refractive index of the sperm heads in conjunction with the orthogonal axes of flow, excitation, and detection in the flow-systems instruments. The theoretical and experimeytal results indicate that the lateral extension can be eliminated either by controlling the sperm orientation with planar flow conditions or by accounting for sperm orientation by means of orientation sensing.

Acridines↗
PubMed1975

Chromosome measurement and sorting by flow systems.

A flow microfluorometer was used to measure metaphase chromosomes in suspension at rates up to 100,000 per min. Chromosomes from cells of the Chinese hamster M3-1 cell line were isolated, stained for DNA with the fluorescent dye ethidium bromide, and analyzed for DNA content. Nine distinct peaks were resolved that correspond well with independent chromosomal DNA measurements made with a high-resolution scanning cytophotometer. Chromosomes were sorted from each peak by an electronic cell sorter. Visual examination of each fraction indicated the purity of the sorted chromosomes. This novel technology allows separation of purified populations of individual chromosomes suitable for biochemical and biological characterizations.

Animals↗
PubMed1975

High-speed quantitative karyotyping by flow microfluorometry.

We describe a new flow-system technique for high-speed quantitative karyotyping. Metaphase chromosomes are isolated from cells, stained with a DNA-specific fluorochrome, and individually measured for stain content at rates up to 10(5)/min in a flow microfluorometer. The resulting distribution contains quantitative information about the relative frequency of occurrence and the chromosomal DNA content of the measured chromosomes. Such analyses of Chinese hamster chromosomes are in good agreement with independent results from scanning cytophotometry and with cytogenetic observations of the banded chromosomes. Analyses of two karyotypically different clones of Chinese hamseter M3-1 lines provide the quantitative characterization of two stable translocations. Initial data on human chromosomes are presented and agree well with results of scanning cytophotometry and suggest potential clinical applications as preparative and instrumental techniques improve.

Animals↗