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Biomedical subjects

R E TAYLOR

Publications and source records attributed to R E TAYLOR.

At least 19 recordsLinked to original sources
PubMed1965

TRANSEPIDERMAL POTENTIAL DIFFERENCE: DEVELOPMENT IN ANURAN LARVAE.

Skin from bullfrog tadpoles does not show the potential difference characteristic of adult frog skin until several days after the emergence of the forelimbs, presumably because the mechanism for active sodium transport is absent or nonfunctional. Exposure to low concentrations of thyroxine accelerates appearance of the transepidermal potential difference at rates which are related to the dosage. This system may provide a new basis for evaluating the importance of specific biochemical mechanisms in active sodium transport.

Animals↗
PubMed1964

DISTANCE PRECEPTION IN DARKNESS.

Human subjects viewed round stimuli located equidistantly in the horizontal and vertical planes of vision under conditions where presumed cues to size were present and where they were systematically eliminated. Two experiments revealed a consistent tendency for the horizon object to be judged the closer. Cues introduced reduced the effect.

Biomedical Research↗
PubMed1964

EFFECTS OF REPLACEMENT OF EXTERNAL SODIUM CHLORIDE WITH SUCROSE ON MEMBRANE CURRENTS OF THE SQUID GIANT AXON.

It was observed that a reduction of the sodium chloride concentration in the external solution bathing a squid giant axon by replacement with sucrose resulted in marked decreases in the peak inward and steady-state outward currents through the axon membrane following a step decrease in membrane potential. These effects are quantitatively acounted for by the increase in series resistance resulting from the decreased conductivity of the sea water and the assumption that the sodium current obeys a relation of the form I = k(1)C(1) - k(2)C(2) where C(1), C(2) are internal and external ion activities and k(1), k(2) are independent of concentration. It is concluded that the potassium ion current is independent of the sodium concentration. That the inward current is carried by sodium ions has been confirmed. The electrical potential (or barrier height) profile in the membrane which drives sodium ions appears to be independent of sodium ion concentration or current. A specific effect of the sucrose on hyperpolarizing currents was observed and noted but not investigated in detail.

Animals↗
PubMed1960

Analysis of certain errors in squid axon voltage clamp measurements.

Localized membrane current and potential measurements were made on the squid giant axon in voltage clamp experiments. Spatial control of potential was impaired by the use of axial current supplying electrodes with surface resistance greater than 20 ohms for a centimeter length of axon. No region of membrane which was indeed subjected to a potential step showed more than one inward current peak. Other patterns were results of space clamp failure. Membrane current and potential patterns during space clamp failure were approximately reproduced in computations on a model containing two membrane patches obeying the equations of Hodgkin and Huxley. Non-uniformities in the axon or electrodes are not necessary for non-uniform electrical behavior. An extension of the core conductor model which includes the axial wire and external solution has been analyzed. The space constant of electrotonic spread is less than 0.5 mm with a usable electrode. Errors of about 5 per cent are introduced by ignoring the external solution. Resistance between the membrane and the control electrodes reduces the control and a few ohm cm(2) could lead to serious errors in interpretation.

Animals↗