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Biomedical subjects

J Gross

Publications and source records attributed to J Gross.

At least 451 records · Page 25Linked to original sources
PubMed1971

In vitro aggregation of mixed embryonic kidney and nerve cells. Influence on macromolecular synthesis.

The possible role of nerve on growth of embryonic parenchymal organs such as kidney was explored by measuring macromolecular synthesis (DNA, RNA, and protein and three enzymes) in aggregates of mixed suspensions of cells from dissociated chick embryo kidney and nerve tissue. One and one-half to threefold increments in net synthesis of the three different types of macromolecules were observed in the mixed aggregates of kidney and nerve cells as compared with those of single organs or mixtures of kidney with nonneural cells. The addition of nerve-growth factor (NGF) did not significantly affect the results. Increased incorporation of label was paralleled by increases in chemically measured DNA and protein, suggesting an increase in growth in the mixed kidney-nerve aggregates compared with those of single tissues. Measurements of survival rate did not indicate increased cell stability in the mixed aggregates. The activities of three enzymes, acid phosphatase, alkaline phosphatase, and lactic dehydrogenase, were also enhanced two to four times in cultures of kidney plus nerve cells. Morphologic studies indicated a high degree of reorganization of tubular structures within the reaggregates of kidney cells alone or in those mixed with nerve. In addition, radioautographs of thymidine-(3)H-labeled cells in the aggregates showed a high level of DNA synthesis in the reformed tubular cells. Electron micrographs revealed the presence of large numbers of nerve fibers containing microtubules in the mixed cell aggregates. The data suggest a significant role for nerve in the growth processes of embryonic parenchymal organs.

Acid Phosphatase↗
PubMed1970

Collagen molecules: distribution of alpha chains.

To ascertain the distribution of alpha chains within the collagen molecule, intramolecular cross-links were introduced into tropocollagen by reacting formaldehyde with dilute homogeneous molecular dispersions of collagen extracted from lathyritic guinea pig skin. Denaturation, chromatography on carboxymethyl cellulose, measurement of molecular weight, and analyses of the amino acids of the cross-linked product indicate that most, if not all, of the collagen molecules consist of two alpha1 chains and one alpha2 chain [(alpha1)(2)(alpha2)(1)].

Amino Acids↗