Acetylcholinesterase activity in the chinchilla organ of Corti in normal and acoustically overstimulated animals.

The distribution of acetylcholinesterase (AChE) positive nerve fibers and endings in the organ of Corti of normal and acoustically overstimulated chinchillas is described. The strongest activity was located in the inner spiral bundle, ane remained almost unchanged even after all the outer and the majority of the inner hair cells had degenerated as a result of intense exposure. In the chinchilla even the apical coil had three rows of AChE-positive nerve endings under the outer hair cells.

Inner ear damage and hearing loss after exposure to tones of high intensity.

Experimental animals (cats) were exposed to tones of 125, 1000, 2000, and 4000 Hz at sound pressure levels in the range 120 to 157.5 dB, and for durations of one hour (1000, 2000, 4000 Hz) or four hours (125 Hz). Pure tone audiograms were obtained for each animal before and after exposure.

The helical content of zein, a water insoluble protein, in non-aqueous solvents.

The conformation of zein, a seed protein from corn, was determined by optical rotary dispersion measurements in a wide variety of nonaqueous solvents. Over a wide range of dielectric constants, in pure and mixed solvent systems, the helical content was independent of dielectric constant. Determination of the helical content of insulin and ribonuclease in several of these solvents indicated a variation in secondary structure comparable of that of zein.