Search PubMed⌕ Search

Biomedical subjects

J GROSS

Publications and source records attributed to J GROSS.

At least 19 recordsLinked to original sources
PubMed1964

THERMAL DENATURATION OF COLLAGEN IN THE DISPERSED AND SOLID STATE.

Thermal denaturation temperature of newly reconstituted collagen fibrils from rat tail tendons is 52 degrees C compared with 42 degrees C for neutral solutions. This suggests that the increase in concentration of collagen within the fibril increases the stability of the individual molecules. The absence of firm intermolecular bonds in these fibrils rules out crosslinking as an explanation for increased stability. "Aging" at 37 degrees C up to 1 year raises the shrinkage temperature of reconstituted fibrous gels by 4 degrees to 6 degrees C and greatly increases resistance to dissolution at high temperature. The newly formed fibrils dissolve without shrinking, whereas older gels exhibit shrinkage before dissolution. Since nearly all extractable collagen is in the form of fibrillar aggregates in tissue, it is unlikely that thermal denaturation occurs at body temperature; therefore it could not be involved as a necessary stage in collagen resorption.

Aging↗
PubMed1964

ORGANIZATION AND DISORGANIZATION OF COLLAGEN.

The organization of the normal collagen molecule and fibrils is reviewed and the detection, assay, and isolation of a collagenolytic enzyme from amphibian tadpole tissue are described and its possible significance in metamorphosis is discussed

Animals↗
PubMed1963

PROVITAMIN A2 FROM LUTEIN.

Alfalfa lipids were treated with p-toluenesulfonic acid in benzene under reflux; after saponification, chromatography of the unsaponifiable portion yielded a carotenoid having a single absorption maximum at 460 mmicro in ethanol and hexane. Its properties correspond to those of the dehydration product of lutein, 3'-hydroxy-3,4-dehydro-ss-carotene, for which the name "anhydrolutein" is proposed. Vitamin A depleted chicks convert this pigment to vitamin A(2), as shown by the high ratio of absorbancies at 693 and 620 mmicro in a mixture of CHCI(3) and SbCl(3). and the absorption maximum at 350 mmicro in hexane exhibited by the liver lipids. The possible role of this pigment in the biogenesis of vitamin A(2) is discussed.

Animals↗
PubMed1963

Experimental lathyrism in the chick embryo. The distribution of beta-aminopropionitrile.

1. C(14)-labeled beta-aminopropionitrile distributed throughout the egg contents within 10 minutes postinjection. By ion exchange chromatography and electrophoretic analysis three major components of the extractable dialyzable radioactive material could be demonstrated, representing at least 80 per cent of the total. The acidic and basic components were identified as beta-aminopropionitrile and cyanoacetic acid, while the fraction isoelectric at pH 5.3, consisting of two components, remained unidentified. 2. Less than 1 molecule of betaAPN per 100 molecules of protein was present in the highly purified extractable lathyritic bone collagen indicating that binding of the lathyrogen is not a factor in collagen extractability. 3. The proximity of betaAPN to collagen in bone is not essential to its extractability. 4. The effect of incubation temperature of the embryo on collagen extractability suggests the involvement of a metabolic process in this phenomenon.

Aminopropionitrile↗