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Biomedical subjects

N Anderson

Publications and source records attributed to N Anderson.

At least 199 records · Page 11Linked to original sources
PubMed1975

Axon voltage-clamp simulations. A multicellular preparation.

In this paper we extend the simulation of the voltage clamp of a single nerve fiber to a bundle of axons. These simulations included not only the description of the voltage clamp circuit and a single unidimensional cable to represent the preparation in the "node" region of a double sucrose gap used previously but also a series resistance and a shunt pathway. The output of the voltage control amplifier is applied across the membrane plus the series resistance, producing a voltage drop across the series resistance due to the current generated by the membrane in response to a depolarizing voltage step. Since the membrane current has an inward and an outward phase, voltage drops of opposite sign are produced across the series resistance. During the transient current and at all points along an axon, the potential deviation produced by the series resistance is opposite to the deviation produced by the longitudinal gradient. Only at a command potential equal to the sodium equilibrium potential, the membrane potential transiently matches the command potential. For the attempted voltage clamp of an axon, values of series resistance larger than 50 omega-cm2 allowed propagated action potentials in the membrane. In spite of the presence of propagated action potentials at the calbe membrane, the recorded current does not show "notches" and it has a phase of inward current and a phase of outward current. It is concluded that, in a multicellular preparation with series resistance, the recording of a square voltage pulse does not indicate voltage control of the transmembrane potential. The presence of a shunt pathway produces inaccurate values of current density. Neither series or shunt resistance produce "notches" in the current records.

Action Potentials↗
PubMed1975

Anthelmintic efficiency related to strategic control schemes for helminthiasis in sheep.

A comparison was made of the effects on worm egg output from groups of sheep treated with either thiabendazole or levamisole at 3 dose rates in different weight categories of weaned lambs. Neither thiabendazole at 79.8 mg/kg nor levamisol at 12.8 mg/kg completely prevented worm egg output by treated sheep. Over all dose rates thiabendazole was significantly more effective than levamisole. The data indicated that dose rates may need to be increased for use in strategic control schemes for helminthiasis.

Animals↗
PubMed1974

Two-hour embedding procedure for intracellular detection of viruses by electron microscopy.

An embedding method requiring only 2 h to complete and giving excellent ultrastructural preservation has been used for the rapid detection of viruses in tissue cultures. The method has also been applied successfully to mammalian tissue. It provides a rapid technique for identifying viruses isolated in tissue cultures, for screening cultures for adventitious agents, and for examining tissue biopsies for viruses.

Adenoviridae↗
PubMed1973

P. A. Earnshaw.

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Australia↗