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Biomedical subjects

L Robert

Publications and source records attributed to L Robert.

At least 289 records · Page 16Linked to original sources
PubMed1975

"In vitro" mucin biosynthesis by human gastric mucosa biopsies.

A method is described for the study of the "in vitro" biosynthesis of mucins by human gastric biopsy samples. 14C-glucose was incorporated in the biopsies obtained from the fundus and antral regions of four normal human donors during a four hours incubation period. Labelled glycoproteins (mucins) were released in the medium and were also retained in the tissue-residue. Neutral sugars, fucose, protein and DNA determinations carried out on the tissue homogenates indicated that significant information on mucin biosynthesis can be obtained by this biopsy procedure which is particularly suitable for the exploration of gastric pathology.

Adult↗
PubMed1975

Isolation, purification and properties of aortic elastase.

An elastase from pig aorta has been partially purified and characterised; it exhibits immunological cross reaction with pig pancreatic elastase. Its proteolytic (k-elastin gel and polymeric elastin substrates) and esterolytic (N-succinoyl-trialanine paranitroanilide) activities as well as its degree of inhibition by serum protease inhibitors (alpha1-antitrypsin and alpha2-macro-globulin) differ sensibly from those of pancreatic elastase [14,16].

Ammonium Sulfate↗
PubMed1975

[Biosynthesis of macromolecules of the intercellular matrix in aorta organ culture. Influence of the age of the animal].

Rabbit aorta organ cultures were used as a model for the study of the modifications of the rate of biosynthesis of intercellular matrix macromolecules with age. Aortas of new born (100 g), young (400 g) and adult (2 kg) rabbits were maintained in culture for several weeks. 14C-lysine is incorporated in all the macromolecular fractions of the aortas, even in polymeric elastin. The change with age of the distribution of proteins of the aorta-explants in successive extracts obtained by a "chemical dissection" procedure and the decrease of their specific radioactivity wtih age enabled us to characterise biochemically the "aging program" of the arterial wall.

Age Factors↗
PubMed1975

Biosynthesis of gastric mucins. In vitro incorporation of radioactive glucose.

An in vitro model for the study of the mechanism of gastric-glycoprotein (mucin) biosynthesis is described. Gastric mucosa scrapings were incubated in Eagle's minimum medium with U-14C-glucose. Linear incorporation-kinetics were observed during 4 hours. U-14-C-glucose was incorporated into soluble and cell bound glycoproteins. In the acid hydrolysate of soluble and cell bound fractions all the amino acids separated by high voltage electrophoresis and all the carbohydrates separated by thin layer chromatography contained appreciable radioactivity showing the active conversion of the added radioactive glucose to all the amino acid and carbohydrate precursors used by the gastric cells for the biosynthesis of macromolecular glycoprotens. The carbohydrate/protein ratio of the excreted glycoproteins increases steadily during the 4h incubation period suggesting that the chemical composition of the excreted mucins changes during this period. The cell bound glycoprotein fraction retains a constant composition during the 4th incubation period. The high fucose to hexose ratio of the soluble (excreted) glycoproteins suggests that they are probably identical to the gastric mucins isolated from native gastric preparation. This model is therefore considered a valid one for the study of the regulation of the biosynthesis of gastric mucins as well as for the study of drug action.

Amino Acids↗
PubMed1975

[Regulation of the biosynthesis of macromolecules of the intercellular corneal matrix].

The influence of a 1M CaCl2 extract and of a collagenase digest of corneal stroma of the biosynthesis of the macromolecules of corneal stroma was investigated. Calf corneas were incubated "in vitro" with radioactive tracers (14C-L-proline; 3H-D-glucosamine or 35SO4) in the presence or absence of the above extracts. After incubation the corneas are submitted to a fractional extraction in order to separate the major macromolecular fractions of the stroma. An increase in incorporation of all tracers is observed in the 1M CaCl2 (CTC), TCA and urea-extracts (containing resp. the diffusible macromolecules, proteoglycans, polymeric collagen and structural glycoproteins) in the presence of the macromolecular extracts and also with the collagenase-hydrolysate of cornea. These results show the existence of a stimulation of the biosynthesis of intracellular matrix macromolecules of the cornea by corneal extracts, probably through positive "feedback" type of mechanism.

Animals↗
PubMed1975

Interaction of platelets with purified macromolecules of the arterial wall.

A method is described for the study of the interaction between human blood platelets and intercellular matrix macromolecules of connective tissues such as those found in the sub-endothelium. The method is based on the qualitative and quantitative evaluation of the elution pattern of a platelet suspension from a mixed Sepharose 2B-fibrous protein column containing standardized amounts of fibrous proteins such as elastin or structural glycoprotein-microfibrils (SGP-MF). No interaction could be demonstrated with this method between platelets and SGP-MF but there was a very distinct interaction between platelets and elastin fibers. This could be confirmed by direct microscopical demonstration of platelet clusters around elastin fibers in cryostat sections of the affinity column.

Arteries↗