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F F Feagin

Publications and source records attributed to F F Feagin.

At least 37 records · Page 2Linked to original sources
PubMed1979

Effect of fluoride on ion exchange, remineralization and acid resistance of surface enamel.

In a system of constant ion activities the rates of F- exchange in enamel, under conditions of exchange alone and remineralization, depended on the concentration of F- in solutions. Acid resistance of surface minerals resulted from exchange of F- for OH- in the enamel at pH 7.0 and 4.5. The level of 0.5 mM NaF, compared to 0.05 and 6.0 mM, caused maximum rates of isotopic exchange of 45Ca and maximum acid resistance of enamel. Similarly low levels of F- may be feasible for use in caries prevention in the absence and presence of remineralization.

Animals↗
PubMed1979

Cell-to-cell communication of osteoblasts.

Osteoblasts were investigated by two methods, electrical conductance and dye injection. Current injection into one cell caused a change in the recorded transmembrane potential of a second cell, indicating high conductance pathways between the two cells. Dyes injected into a single osteoblast were transmitted to numerous surrounding cells.

Animals↗
PubMed1978

Transmembrane potentials of osteoblasts.

Transmembrane potentials were recorded in situ from osteoblasts on the parietal bones of albino rat pups, 3 to 24 days of age. Osteoblasts exhibit a uniquely low polarization of their cell membranes (3.93 mV, inside negative). Osteoblasts respond rapidly, but transiently, to parathyroid hormone by depolarization, and to thyrocalcitonin by hyperpolarization.

Animals↗
PubMed1977

Effects of bicarbonate on remineralization of enamel.

Enamel surfaces were demineralized in acetic acid and remineralized in solutions that contained 1.5 mM calcium, 1.0 mM phosphate, and 0.0, 5, 15, and 25 mM NaHCO3, and 0.00 or 5.0 mM Naf at pH 7.0. NaF in CO2-free solutions increased the rates of calcium and phosphate uptake during remineralization. Bicarbonate in NaF-free solutions caused small increases of calcium and phosphate uptake. Bicarbonate with NaF in solutions synergistically increased calcium uptake, but did not affect phosphate uptake. Bicarbonate reduced fluoride uptake by about 50% during remineralization, and increased the Ca/P ratios of deposited minerals from about 1 (dicalcium phosphate) to approach and exceed the ratios of apatites.

Animals↗
PubMed1975

Effect of matrix bound phosphate and fluoride on mineralization of dentin.

Completely demineralized bovine dentin mineralized to a high degree, but only after extraction of about half of its organic phosphate. Initiation of mineral formation depended on the concentrations of Ca2 plus, Pi, HCO3 minus and H plus ions in the incubation solution. After nucleation, mineral accretion by the dentin continued in solutions that did not, themselves, initiate mineralization. The nucleation phase, but not the subsequent accretion of mineral, was sensitive to small changes in temperature. Inclusion of 0.05 mM NaF in the solution markedly reduced the amount of mineral deposited during the nucleation phase but apparently enhanced subsequent mineralization.

Acetates↗