Biomedical subjects

L Gotte

Publications and source records attributed to L Gotte.

13 recordsLinked to original sources

PubMed1990

Degradation of immobilized soluble elastin by tumor cells in culture: quantitation by ELISA.

A new, sensitive assay based on the enzyme-linked immunosorbent assay has been developed for measuring elastolytic activity produced by invasive and/or metastatic tumor cells in culture. Elastin peptides, obtained by treating the insoluble protein with either oxalic acid, KOH, or chymotrypsin, are adsorbed onto the surface of cell culture microtiter plastic wells, and incubated with dilution of standard proteinases or viable normal or tumor cells. The total amount of immobilized elastin peptides is revealed by the mean of specific antibodies, and detected by a microplate reader, while dose- and time-dependent reduction of bound antibodies after incubation with proteases or cells is taken as a measure of elastin degradation. Adsorbed elastin has been found to be available as a substrate for purified enzymes, as well as for living melanoma cells (A2058 and B16-BL6), c-Ha-ras transformed rat embryo fibroblasts, and human pulmonary macrophages, as demonstrated by the release into the culture medium of lower molecular weight digestion products. No degradation was achieved by BALB/3T3 and rat embryo control fibroblasts, and no inhibition was produced by the presence of fetal calf serum which, on the contrary, potentiated the degradation by active cells. This new method, revealing degradation of only a few nanograms of soluble elastin peptides, can be used for studying the importance in tissue invasion and metastasis of elastolytic proteinases produced by cells in culture.

Animals↗

PubMed1987

The use of reverse-phase high-performance liquid chromatography and precolumn derivatization with dansyl chloride for quantitation of specific amino acids in collagen and elastin.

A rapid and accurate reverse-phase high-performance liquid chromatography procedure for amino acid analysis of connective tissue proteins has been optimized. The method is based on quantitative dansyl chloride precolumn derivatization of protein hydrolyzates and chromatographic separation of the dansyl derivatives on Ultrasphere ODS C18 column. High molar uv absorption of Pro and Hyp derivatives, quantitation of low Des and Ide amounts (60 pmol), and good separation of all the amino acid derivatives (CV mostly less than 0.1%) including Hyl overcome the difficulties of other methods in producing reliable single run amino acid analysis of collagen and elastin. The use of fluorescence detector and the possibility of concentrating derivatized samples would give even higher sensitivity to the system. The procedure appeared to be suitable for single run analysis of other proteins, particularly those having an unbalanced amino acid composition.

Amino Acids↗

PubMed1979

Fibrogenesis and biosynthesis of elastin in cartilage.

This study presents direct evidence that dissociated chondroblasts from rabbit ear cartilage grown in vitro are capable of synthesizing insoluble elastin. Ultrastructural examination indicated that at an early stage of tissue development, elastogenesis is initiated producing a form of primary fibrils which later condense into an electron dense amorphous material which, unlike other elastin-containing tissues, is heavily stained by metal cations and lacks peripheral microfibrils. Native elastic fibrils and the mature elastic fiber bundles are both susceptible to elastase digestion. Transmission electronmicroscopy demonstrated the presence of many intracellular filaments all showing a substructural organization and localized in close proximity to the nucleus. Their possible contractile nature is discussed. Amino acid analysis of cartilage elastin and of the elastin synthesized in vitro revealed a close chemical similarity between the two molecules. Ultrastructural analysis of the in vitro elastin demonstrated a substructural organization quite similar to that of the elastin observed in an in vivo system.

Amino Acids↗

PubMed1977

Recent observations on the structure and composition of elastin.

The ultrastructural organization of elastin has been studied by scanning and transmission electron microscopy of negatively stained specimens coupled with optical diffraction analyses. Purified elastin results from a composite assembly of interwoven branched and twisted thread-like entities of decreasing diameter. The ultimate filamentous component is a rope-like structure each with an overall diameter of 3.5-4.0 nm consisting of paired filaments of indefinite length each 1.5 nm in width and periodically linked longitudinally at a varying distance of 3.5 to 4.5 nm depending on the degree of stretch.

Amino Acid Sequence↗

PubMed1976

Banded figers in high temperature coacervates of elastin peptides.

Electron micrographs of negatively stained coacervates of the synthetic polypentapeptide of propoelastin and of alpha-elastin exhibit banded fibers when the coacervates are formed, stained, and dried at temperatures greater than 50 degrees. This apparent increase in order occurs at the same temperature as an increase in order in aqueous solution and as a change in the volume expansion coefficient of fibrous elastin.

Elastin↗

PubMed1976

Optical diffraction of tropoelastin and alpha-elastin coacervates.

Optical diffraction applied to micrographs of coacervated tropoelastin and alpha-elastin show an equatorial repeat around 50 A. This confirms a 50 A center-to-center distance of parallel aligned filaments to be a fundamental property of the tropoelastin and alpha-elastin coacervates. This periodicity is similar to that of mature cross-linked elastin. These results allow the conclusion that hydrophobic association is the predominant driving force for formation of filamentous elastin in vitro. It is suggested that the coacervate is a model for relaxed fibrous elastin.

Elastin↗

PubMed1976