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Biomedical subjects

J GROSS

Publications and source records attributed to J GROSS.

At least 55 records · Page 3Linked to original sources
PubMed1959

Morphologic evidence for collagen changes in chick embryos treated with beta-aminopropionitrile.

Electron microscope analysis of thin sections of intact skin from 17 day chick embryos injected with beta-aminopropionitrile 3 days earlier, revealed markedly increased dispersion in fibril diameter both above and below the narrow distribution of normal fibril size. Extraction with cold 1 M neutral saline caused a dissolution of the fibrils to fine filaments of varying diameters. Histologic examination of the connective tissue of lathyritic skin prior to extraction revealed little difference from the normal. After extraction the collagen either disappeared almost entirely or was observed as a homogeneous smear. These results of morphologic analysis are consistent with previous chemical studies, supporting the thesis that lathyrogenic agents induce disruption of intermolecular cross-linking within normally insoluble collagen fibrils, allowing them to dissolve in cold neutral salt solutions.

Aminopropionitrile↗
PubMed1959

Alterations in state of molecular aggregation of collagen induced in chick embryos by beta-aminopropionitrile (lathyrus factor).

The lathyrogenic agents, beta-aminopropionitrile and semicarbizide, when applied to the chorio-allantoic membrane of the chick embryo produced a dramatic increase in fragility of the embryo. This alteration was not associated with a change in the concentration of collagen, except in aorta, but was accompanied by a sharp increase in the amount of collagen extractible in cold 1 M NaCl from skin, bone, and aorta. Increase in fragility and extractible collagen began within 3 hours after introduction of the agent and rose steadily for at least 72 hours. Essentially no collagen could be extracted from tissues of normal chick embryos. Both fragility and amount of extractible collagen were dosage- and time-dependent. It is concluded that the extractible collagen in lathyrism consists of a large proportion of dissolved fibers previously insoluble and formed prior to administration of the agent. The data also suggest that the "lathyritic" collagen in vivo is not in molecular dispersion but in an aggregate or fibrillar form. It is dispersed by cooling. The extracted collagen could be reconstituted to typical striated fibrils in vitro and the molecule appeared to be normal in the gross, with regard to asymmetry ratio and intramolecular helical structure. The evidence at hand suggests that at least one of the defects induced by lathyrogenic agents is an interference with the normal intermolecular cross-linking within the collagen fibril.

Aminopropionitrile↗
PubMed1959

Studies on the formation of collagen. IV. Effect of vitamin C deficiency on the neutral salt-extractible collagen of skin.

The skin of severely scorbutic guinea pigs which were losing weight contained no detectible neutral salt-extractible collagen. Conditions of growth (weight gain) which actively induced the formation of neutral salt-extractible collagen in the skin of normal guinea pigs failed to do so in the animal with ascorbic acid deficiency. No excess of non-collagenous proline was found in neutral salt extracts of scorbutic skin as compared with normal. Fractionation of these extracts failed to reveal the presence of significant amounts of a soluble component containing unusual proportions of glycine and proline relative to hydroxyproline. It is concluded that deficiency of ascorbic acid either interferes with the synthesis of new collagen in intact skin or causes its destruction and removal as rapidly as it is produced.

Animals↗