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Biomedical subjects

R Katzman

Publications and source records attributed to R Katzman.

At least 145 records · Page 8Linked to original sources
PubMed1969

Sodium and potassium distribution in puffer fish supramedullary nerve cell bodies.

The Na and K concentration in single supramedullary neurons of the puffer fish (Spheroides maculatus) was measured using a dual channel integrating ultramicroflame photometer. The cells were frozen in situ, sectioned at low temperatures, and freeze-dried to prevent artefactual movements of cations. The density of the nuclear fragments was 0.15, significantly less than cytoplasm's 0.21. The sucrose-(14)C "space" was 2.1-4.7% in cytoplasm fragments and 0.9-2.1% in nuclear fragments. The K concentration in cytoplasm averaged 134 mmoles/liter tissue volume and in nuclei, 113. The Na concentration in cytoplasm fragments varied between 56 and 138 mmoles/liter per tissue volume; in nuclei between 40 and 135, and in perineural tissue between 55 and 114. This intracellular Na is several times greater than the Na concentration expected from previous estimates. It is probable, however, that the intracellular Na activity is less than half that of the Na concentration, suggesting that much of the intracellular Na is bound to organic molecules within the cell.

Animals↗
PubMed1968

Ionic interaction of sulfatide with choline lipids.

Aqueous systems of sphingomyelin-sulfatide and lecithin-sulfatide were compared with aqueous systems of the individual lipids. The acid capacity of the mixed lipids increased, a result of the formation of an ionic bond between the sulfate of one molecule and the positive nitrogen of the other, making the phosphate available for direct titration. Cholesterol reduces this ionic interaction, probably because of the increased spacing of the ionized groups.

Chemical Phenomena↗