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At least 631 records · Page 35Linked to original sources
PubMed1985

[Light- and electronmicroscopic investigations of the development of the stria vascularis in the ductus cochlearis of the guinea pig fetus].

Our studies on exactly dated guinea pig fetuses show: Already in early stages of development (37th day), in the anlage of the vascular stria vesicular invaginations of the apical plasmalemma of epithelial cells are noted and regarded as a sign of an exchange of substances between epithelial cells and the endolymph. As to the direction of substance transport, the morphological finding allows no decision. From the 42nd to the 44th day of development, the subepithelial basal lamina becomes progressively indistinct. From the 45th day onward, the basal lamina is not yet demonstrable. The largest part of the chromophobe cells of the vascular stria derives from the mesenchyme. The question, whether some of the chromophobe cells are of epithelial origin, as some authors propose, will hopefully be clarified in further studies.

Animals↗
PubMed1984

[Cochleomeatal scintigraphy].

High resolution cochleomeatal scanning has proven to be a simple and inexpensive diagnostic method in tumors of the inner auditory canal, resp. of the cerebello- pontineangle . In 112 neurotologic patients (37 with proven acoustic neuromas) there were no false positives or false negatives. Therefore, the use of invasive or expensive tests in suspicion of tumors of the 8th cranial nerve should be restricted to those cases with positive scans. CMS is of special diagnostic value in patients with absent air insufflation of the basal cisternae in gas computerised tomograms and in suspected tumor recurrences. Dynamic studies with determination of the radiopharmacokinetics of radiopharmacology reveal further differential diagnostic aspects.

Cochlear Duct↗
PubMed1983

[Current histopathological findings in Ménière's disease].

Controversy exists as to the presence of ruptures of the membranous labyrinth in patients with Meniere's disease, some authors considering the lesions reported to be artefacts only. Confirmation of the existence of healed labyrinthine tears was obtained in all cases of clinically and histopathologically confirmed Menière's disease studied by means of a protocol involving strict criteria. Lesions were observed mainly in Reissner's membrane and demonstrated three particular aspects. It is suggested that the images described by Out-Pouch in the posterior labyrinth are also the result of healed ruptures.

Cochlear Duct↗
PubMed1981

[Physiopathology and clinical aspects of Menière's disease].

The most prominent changes in temporal bone histopathology of Menière's disease are hydrops-like extensions of the endolymphatic spaces. The endolymphatic hydrops seems to be the consequence of a diminished function or complete atrophy of the endolymphatic sac. The etiology or pathomechanism of perisaccular fibrosis or saccular degeneration is unknown. But as a consequence of experimental datas obtained by animal studies the pathogenesis of the endolymphatic hydrops can be explained by osmotic active forces which develope within the endolymphatic spaces after blockage of the endolymphatic aqueduct or sac: An increasing concentration of osmotic active endolymphatic components cause an influx of water from the perilymphatic (extracellular) environment so that the limiting membranes of the endolymphatic space have to extend (e.g. Reissner's membrane, saccular membrane). At any topographic location of the endolymphatic spaces these membranes can rupture followed by intermixing of potassium-rich endolymph with sodium rich perilymph. This leads to an acute or chronic intoxication of those sensory nerve elements which have close contact to perilymphatic fluid. The hypothesis of an osmotic induced accumulation of "water' during endolymphatic hydrops is supported by sometime striking results of the glycerol test. Nevertheless, the pathogenesis and etiology of Menière's disease remains obscure, as indicated by the diverging spectrum of the different conservative or surgical therapeutic methods in use.

Animals↗
PubMed1981

[Physiological nuclear size pattern of sensory cells in the guinea pig cochlea].

The present investigations has been carried out in order to get a base for quantitative recording of nuclear size changes of guinea pig cochlear sensory cells which are be found after noise exposure. The nuclei of normal cochlear hair cells differ in size. Inner hair cell nuclei are rapidly increasing in size at the first third of the basal turn and reach a maximum at the transition to the second turn. Up to the cochlear apex they are decreasing in size until they have reached the size of the lower basal turn again. Outer hair cell nuclei are clearly smaller than inner hair cell nuclei in the first three turns. From basal to apical outer hair cell nuclei show an almost linear increasing in size and at the end of the fourth turn they are nearly comparable with those of inner hair cells. There are no significant differences in nuclear size between the three rows of outer hair cells in the first and second turn. In the third turn however an increase of size of outer hair cell nuclei from medial ot lateral could be found.

Animals↗
PubMed1980

Idiopathic sudden hearing loss.

Idiopathic sudden hearing loss is an otologic emergency with an obscure cause. It is the acute onset of hearing loss of 30 cB in three contiguous frequencies, which may occur instantaneously or progressively over several days. Suspect etiologies include viral infections, cochlear artery occlusion, rupture of the intracochlear membranes, and biochemical alterations in the metabolism maintaining the endocochlear membrane potentials. Histopathology of the temporal bone most commonly reveals atrophy of the organ of Corti and striae vascularis. Treatments proposed include close observation for spontaneous recovery, steroid theray, and combination regimens of vasodilators, steroids, diuretics, and intravenous iodinated radiocontrast material. Prognosis and recovery are related to the audiometric pattern of the hearing loss and associated symptoms. The absence of vertigo at th clinical onset and low tone hearing loss are associated with better hearing recovery.

Adult↗
PubMed1994

[Relationship between summating potentials and perilymphatic fistula].

Serial electrocochleogram (ECochG) recordings were obtained within 24 hours from 40 guinea pigs with experimentally induced PLF, and the cochlears of 30 guinea pigs (60 ears) were histopathologically observed under light microscope. -SP occurred in 100% experimented ears within 1-3 hours after PLF, but distention of Ressner's membrane was found only in 30% ones. CAP thresholds and N1 latencies of 10 animals were improved, accompanying disappearance of -SP in 6 of the 10 animals in 24 hours after PLF. It is presumed that -SP is not a specifically electrophysiologic indicator of ELH, and that the generation of -SP may chiefly result from reversible damage of cochlear hair cells. The mechanical factor of basilar membrane displacement can hardly be considered as a main cause of SP abnormality. The mechanism of the ELH following PLF was also discussed.

Animals↗
PubMed1993

[Experimental study on the therapeutic value of microwave on hearing loss due to ethacrynic acid ototoxicity].

Ischemia of the stria vascularis in the cochlea associated with temporal hearing loss was found in guinea pigs with intravenous othacrynic acid injection. Using this animal model, we studied the therapeutic value of low power density microwave on the ischemic stria vascularis. Experimental findings confirmed that microwave irradiation on the ear might prompt a quicker recovery of hearing. Meanwhile, milder pathological changes of the stria vascularis were shown either on light microscopy or on TEM in the microwave treated animals. Hence, it is suggested that microwave irradiation causes an improvement of microcirculation and an alleviation of lesions in the stria vascularis. The study has provided an experimental basis of microwave treatment for the hearing impairment due to microcirculation disorder in the inner ear.

Animals↗