Franz Altmann

LXII Further Investigations on the Physiology of the Labyrinthine Fluids

In a previous paper, the authors reported preliminary experiments designed to investigate some questions pertaining to the physiology of the labyrinthine fluids (Altmann and Waltner,2 1947). Using the method employed by Weed in his studies of the resorption of the cerebrospinal fluid, solutions of iron-ammonium citrate and potassium ferrocyanide in various concentrations and oxalated chicken blood were introduced into the subarachnoid space of rabbits and traced in two instances into the labyrinth.

LVIII The Circulation of the Labyrinthine Fluids: Experimental Investigations in Rabbits

The endolymph flows, according to Guild who draws his conclusions from the results of experiments on guinea pigs, towards the basal end of the cochlear duct, through the ductus reuniens into the saccule. From there it goes into the endolymphatic sac. It leaves the membranous labyrinth by passing through the wall of the pars intermedia of the saccus into the numerous small blood vessels in this region. Guild also postulates a flow from the utricle and the semicircular canals in the same direction towards the saccus endolymphaticus. This would imply the assumption that endolymph is also formed within the utricle and the semicircular canals. According to Wittmaack this formation takes place in the macula and the cristae and in the so-called atypical epithelial formations of the utricle. Wittmaack also thinks that the resorption of endolymph takes place mainly in the endolymphatic sac but that a certain part of it diffuses through the membrane of Reissner into the scala vestibuli.

Pathologic changes in the inner ear of audiogenic seizure-susceptible mice treated with 6-aminonicotinamide

Abstract The inner ears were studied histologically to determine a possible morphological basis for our earlier finding of the abolition of sound-induced seizures in inbred audiogenic seizure-susceptible mice treated with 6-aminonicotinamide (6-AN). A single intraperitoneal injection of 20 mg/kg of 6-AN resulted in elimination of sound-induced seizures and produced severe degenerative lesions in the cochlear duct of the seizure-susceptible mice. Similar cochlear lesions were produced in a control mouse strain (CF#1). The earliest lesions, first sought and clearly evident at 24 hours after the injection, were localized in the spiral ligament, the epithelium of the external spiral sulcus, and the lateral portions of the papilla acoustica. The acute degeneration was at its highest 3–5 days after the injection, when the medial portions of the papilla were also involved. The damage to the spiral organ (Corti) seen at that time is incompatible with a normal sensory input. The degree of damage is sufficient to explain the loss of, or marked restriction in, response to auditory stimuli, and the abolition of audiogenic seizures. In all animals treated with 6-AN, the lower basal turn and the upper second turn were more extensively damaged than the rest of the cochlea. However, in the longest surviving 6-AN-treated mice not even a remnant of the spiral organ could be detected. The spiral ganglion nerve cells were not damaged in the acute stage of 6-AN intoxication. The atrophy of the spiral ganglion which appeared in the late stages was, like the degeneration of the spiral organ, most severe in the lower basal and upper second turns. The changes in the spiral ganglion were interpreted as being secondary to the acute destruction of the spiral organ.

XXIX The Surgical Treatment of Ménière's Disease Experimental and Clinical Investigations

The indications for operative treatment could, however, be considerably broadened if a method could be found which destroys the vestibular function or at least enough of it to eliminate the vertigo and at the same time preserve or even improve the hearing. The indications would then also include the by no means rare bilateral involvement of the labyrinth and the frequent cases with still usable hearing in the affected ear.

KAWAMOTO AND ALTMANN'S CRISTA NEGLECTA-Reply

To the Editor .—Although the question brought up by Dr. Gacek might hardly be of sufficient interest to a reader not familiar with this highly specialized problem, I gladly follow your kind invitation to comment on Dr. Gaceks remarks. In describing the structure interpreted by me as crista quarta (1961), I mentioned the absence of nerve fibers and pointed out that the side walls of the formation are covered with cuboideal, the crest with columnar epithelium in which, due to poor preservation, no further details can be made out. It is difficult for me to perceive how Dr. Gacek could conclude from the examination of a photomicrograph with certainty that sensory elements were absent when I, after a thorough study of the microscopic slides was unable to come to a definite opinion. Dr. Gacek furthermore does not take the fact into consideration that the structure in question is covered