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Biomedical subjects

L Naftalin

Publications and source records attributed to L Naftalin.

8 recordsLinked to original sources

Mechanoelectrical transduction, ion movement and water stasis in uromodulin.

Mechanical movement of a column of the urinary glycoprotein uromodulin modulates an applied voltage. This change is a property of the glycoprotein and its interaction with the walls of the container and is related to its capacitance. The voltage modulation is not accompanied by changes in rotationally restricted water as has been reported for hyaluronic acid. Diffusion experiments with tritiated water also support the hypothesis that uromodulin acts as a water barrier, but allows ion movement.

Electrochemistry

The peripheral hearing mechanism: new biophysical concepts for transduction of the acoustic signal to an electrochemical event.

A theory of peripheral function in hearing is proposed. It accounts for temporal discrimination among simultaneously received wave and pulse signals, cochlear analysis of acoustic input, and transduction of acoustic energy into biochemical energy by means of resonance and ion-shuttling involving the tectorial membrane and hair-cell complex. The postulated mechanism is such that it can accommodate the enormous range of intensity accessible to the mammalian ear. Synthesized by the theory are numerous empirical observations and experimental results reported by a broad gamut of disciplines but hitherto not unified. Additional support derives from the characteristics of an artificial "cochlea" and an electret (protein) microphone or "ion exchange microphone" with implications for enzyme conformational change.

Acoustic Stimulation

The peripheral hearing mechanism: a biochemical and biological approach.

A new approach is described to the problem or hearing at energy levels near threshold. Models depending on the macro-physics of levers are rejected. Instead, evidence is presented for frequency analysis, signal placement and energy transduction by the properties (known or experimentally determined) or the cochlea and of the structures within the scala media. The hypothesis developed rests on the established theorems of Gabor and Brillouin, and at the same time is based on the data of enzymology. Care is taken not only that the hypothesis does not conflict but that it is actually consonant with recent solid state physics. The cochlea by virtue of its internal geometry and contained column of fluid is considered to perform a Fourier analysis to a first approximation. This crude "placement" of the acoustic signal is refined by the semi-solid-state lattice of the tectorial membrane which far from permitting dissipation of the signal energy actually "concentrates" the energy at the membrane surface of the hair processes of a hair cell. Here biochemical transduction, akin to the processes known for other sensory cells, transforms acoustic energy through an ion-shuttling mechanism to the form of energy characteristic of living cells, viz. enzyme conformational changes.

Cochlea