Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Labyrinthine Fluids”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 865 records · Page 48Linked to original sources
PubMedDate not supplied

Rates of ion movement from plasma to endolymph in the dogfish.

The rates of movement of Na+, Rb+, Cl- and HCO3- from plasma to endolymph were studied in the elasmobranch fish, Squalus acanthias, by use of the appropriate isotopes. Rb+ was used as a marker for K+. The half-times to equilibrium for Na+, Rb+ and Cl- were about 100 hours; for HCO3- it was 6 hours. The equilibrium ratios, endolymph/plasma, are Na+ 0.87, K+ 26, Cl- 1.37, HCO3- 1.47. Carbonic anhydrase inhibition decreased the rate of HCO3- accumulation, suggesting that the process is actually the formation of endolymphatic HCO3- from plasma or tissue CO2. Increase in plasma pCO2 elevates endolymph HCO3- concentration. The secretory tissue contains carbonic anhydrase and Na-K-ATPase. These and other data suggest that a dominant feature of endolymph chemistry may be HCO3- formation linked in some fashion with K+ transport, through rates catalyzed by these two enzymes.

Acetazolamide↗
PubMedDate not supplied

Unilateral endolymphatic hydrops and associated abnormalities.

A case of unilateral endolymphatic hydrops is presented in which several significant histopathological findings are observed in the affected inner ear and are absent in the opposite ear. Moderate endolymphatic hydrops is present in all cochlear turns on the involved side. Atrophic changes in the cochlear and vestibular end-organs, partial collapse and infolding of Reissner's and the saccular membranes, and collapse of the posterior canal membrane are also seen. There is also marked narrowing of the proximal rugose portion of the endolymphatic sac, associated with a flattened, epithelial lining, dense fibrotic connective tissue, brown pigment deposition, and poor vascularity in a relatively narrowed and straightened vestibular aqueduct. Fibrosis, loss of vascularity, and brown pigment deposition are also observed in the bony channels surrounding the vestibular aqueduct.

Cochlea↗
PubMedDate not supplied

Sudden deafness: histopathologic correlation in temporal bone.

The histopathological study of two cases of sudden deafness is presented. The temporal bones showed cochleosaccular abnormality. The most striking pathological changes were collapse of the organ of Corti, atrophy of the tectorial membrane, atrophy of the stria vascularis, decrease in the number of the cochlear nerves, collapse of the saccular membrane and partial absence of the sensory epithelial layer in the saccular macula. These changes are quite similar in type to those occurring in labyrinthitis of known viral etiology and to those in previously reported cases of sudden deafness which were assumed to be of viral origin. This evidence suggests that a viral infection was the most probable etiology of sudden deafness in these ears. In addition, unusual findings of endolymphatic hydrops limited to the extreme basal end of the cochlear duct were found in Case 1. A patent cochlear aqueduct and circumscribed perilymphatic labyrinthine ossification in the superior seimicircular canal were also observed. With these histopathological findings, the possibility of viral infection via the meninges as well as via the hematogenous route into the inner ear is proposed.

Cochlea↗
PubMedDate not supplied

Current status of surgical decompression and drainage procedures upon the endolymphatic system.

At the present time, neither the etiologic factors nor the pathophysiologic mechanisms that lead to the development of endolymphatic hydrops or Ménière's disease are known; however, the anatomic-pathologic alterations in the labyrinth that are produced by the disease are well-documented. Undoubtedly, what is not known is responsible for the controversial status and questionable benefit that surgical decompression and drainage procedures have upon the endolymphatic system.

Animals↗
PubMedDate not supplied

Perilymphatic oxygen tension and vasoactive drugs.

The oxygenation of the perilymph in response to the intravenous injection of vasoactive drugs has been measured in 67 cats using the polarographic method. Of all drugs used, only angiotensin induced a significant raise of perilymphatic PO2. Histamine, 50% glycerol and 7% Na2CO2 reduced the perilymphatic PO2. Papaverine, furosemid, pyridylcarbinol, naftidrofuryl and low molecular dextran have no significant effect upon the perilymphatic oxygen tension. Rapid changes of systemic blood pressure were found to correlate with subsequent modifications of the oxygen tension in the perilymphatic space.

Angiotensin II↗
PubMedDate not supplied

Delayed endolymphatic hydrops.

Delayed endolymphatic hydrops is a disease entity that can be differentiated from Ménière's disease. Typically it occurs in patients who have sustained a profound hearing loss in one ear, usually from infection or trauma, and then after a prolonged period of time develop either episodic vertigo from the same ear (ipsilateral delayed endolymphatic hydrops) or fluctuating hearing loss, also sometimes with episodic vertigo, in the opposite ear (contralateral delayed endolymphatic hydrops). The ipsilateral form of the disease may be treated by labyrinthectomy but no satisfactory therapy is available for the contralateral form of the disease.

Adolescent↗
PubMedDate not supplied

Minute perilymph fistulas: vertigo and Hennebert's sign without hearing loss.

The clinical entity characterized by episodic vertigo and a positive Hennebert's sign in patients without hearing loss is described. The history of perilymph fistulas is reviewed. Minute perilymph fistulas of the oval window were documented surgically in five consecutive patients with this syndrome. All experienced relief of their symptoms after surgical correction.

Adult↗
PubMedDate not supplied

Variation of endocochlear PO2 and cochlear potentials by breathing carbon dioxide.

The effect of carbon dioxide on oxygen dioxide tension in the endolymph was determined by the micropolarographic technique. Different concentrations (5% and 10% CO2) and different exposure times (3, 5, and 20 minutes) were investigated. The highest levels of PO2 in the endolymph (101.7, 93.9 and 69.5 mm Hg) were accomplished by respiration of 10% CO2, 90% O2, for 20, 5 and 3 minutes consecutively. The lowest PO2 increase, 50.7 mm Hg was observed after breathing 5% CO2, 90% O2 for 20 minutes. Extreme hypercapnia caused an increase of endocochlear potentials (EP) in all groups. In the second group EP increased from +79.3 to +84.9 and in all groups they had returned to the pretreatment level after CO2 discontinuation. These results support the theory that carbonic anhydrase participates in the generation of EP. At the same time that EP increased, cochlear microphonics declined and opposite after the breathing mixture was discontinued. The results permit the conclusion that high levels of PO2 in endolymph is achievable even with short periods of respiration with high CO2 mixture, and suggest the role of carbonic anhydrase during EP generation.

Action Potentials↗
PubMedDate not supplied

Effect of cholinergic drugs on the perilymphatic oxygen tension.

The effect of the intravenous injection of cholinergic drugs on perilymphatic oxygen tension (PO2) was measured using the polarographic method in 20 cats. Acetylcholine, pilocarpine and neostigmine produced minimal but statistically significant changes in perilymphatic PO2. Atropine and scopolamine did not influence the PO2 of the perilymphatic space. The reported results show that under normal conditions the cholinergic receptors of the vestibular vessels have little effect on the permeability of arterial PO2.

Acetylcholine↗
PubMedDate not supplied

Surgical treatment of recurrent perilymph fistula with anacusis.

A woman with substantiated well-preserved premorbid cochlear function developed right-sided anacusis due to a perilymph fistula twice at an interval of 20 months. The fistula was presumably a sequel to previous operative damage to the stapes footplate. On both occasions she was treated surgically with a good result.

Audiometry↗
PubMedDate not supplied

Pendred's syndrome with atypical features.

One of seven cases of Pendred's syndrome had mixed hearing loss, bilateral congenital stapes foot-plate fixation, surgically proven unilateral perilymph fistula and delayed fluctuating hearing loss in the unoperated ear. A unifying hypothesis is proposed to link these diversified findings.

Adolescent↗
PubMedDate not supplied

Menière's disease and endolymphatic hydrops: clinical-histopathological correlations.

The clinical-histopathological correlation between Menière's disease and endolymphatic hydrops was done to explain, as much as possible, causes of symptoms of Menière's disease. Twenty-three temporal bones with endolymphatic hydrops from 17 patients were reviewed and clinical and histopathological findings were correlated. Histopathological examination revealed frequent, severe deformities in the labyrinthine walls and permanent changes in Reissner's membranes. Evidence of rupture was difficult to assess. Of 21 ears of patients with the clinical diagnosis of Menière's disease, 93% had endolymphatic hydrops. A statistical correlation between increased area of the cochlear duct and hearing loss was found. Some correlation was also found between frequency of vertigo and results of electronystagmography with histopathological findings. Consequently, the mechanical effect of endolymphatic hydrops seems to have greater significance in the production of symptoms of Menière's disease than the biochemical effect of ruptures. In a review of ten unusual cases from this series of 17 patients, traumatic neuromas or remnants of vestibular structures were found after an incomplete labyrinthectomy. Histopathological findings of four patients who had undergone endolymphatic subarachnoid shunt surgery are described.

Adult↗
PubMedDate not supplied

Endolymphatic hydrops. An overview and classification.

Endolymphatic hydrops (EH) is a pathological condition which is the final common manifestation of a variety of otologic insults. In this paper we develop a classification which, on the basis of clinical and pathological data, distinguishes symptomatic and asymptomatic forms. Clinical case histories and temporal bone studies are presented to illustrate and substantiate this classification. The symptomatic form becomes evident by the hallmark symptoms of episodic vertigo and fluctuating hearing loss. The asymptomatic form is silent. Interconversion from one form to another may occur over time. Each of the forms can be subdivided, according to etiology, into embryopathic, acquired, and idiopathic types. The embryopathic type comprises those cases in which some noxious influence interferes with prenatal labyrinthine development. The acquired type includes those cases in which a documented insult, be it inflammatory or traumatic, is suffered by a previously normal labyrinth. The inflammation may be viral, bacterial, or spirochetal in nature, while the traumatic event may be either accidentally or surgically sustained. The idiopathic type includes cases in which the instigating event precipitating the EH is unknown. Menière's disease represents merely one example of the EH group of disorders, namely symptomatic idiopathic EH.

Adolescent↗
PubMedDate not supplied

Effect of a middle ear immune response on inner ear antibody levels.

The effect of a middle ear immune response upon antibody levels in the perilymphatic compartment of the inner ear was investigated in the guinea pig. Animals were systemically sensitized with keyhole limpet hemocyanin (KLH) and bovine serum albumin (BSA) until high circulating levels were achieved. The middle ear cavity was then challenged with KLH, resulting in a vigorous immune response with effusion and mucosal inflammation. Antibody levels against KLH and BSA were then compared in serum, middle ear effusions, and perilymph. Anti-KLH levels in perilymph were found to increase substantially during middle ear response to challenge, while the anti-BSA levels did not, indicating a local origin for the anti-KLH antibody. The most likely explanations for these findings are inner ear antibody originated in the middle ear and diffused across the round window membrane, or antigen diffused across the round window membrane and evoked local production of antibody within the inner ear.

Animals↗
PubMedDate not supplied

Perilymphatic fistula: a histopathologic study.

Over the last two decades, clinical criteria for perilymphatic fistulae have been defined to the extent that differentiation can be made between such fistulae and other balance-affecting disorders such as Meniere's syndrome. On the assumption that the specimens in the temporal bone bank of the University of Chicago Medical School that had been obtained from patients having vertigo, hearing loss, or both, before those clinical criteria were so defined might have been classified incorrectly, we proposed a retrospective histopathologic study, with prediction of two independent variables: a clinical history and physical findings consistent with the diagnosis of perilymphatic fistula and communication between the vestibule and the middle ear adjacent to or via the fissula ante fenestram. Eleven pairs of temporal bones with the histologic diagnosis of idiopathic labyrinthine hydrops were evaluated before the clinical histories relevant to those specimens were reviewed. In one specimen, a communication between the vestibule and the middle ear space was identified. In none of the other specimens was there a similar communication. As this study continued, significance was given to the histologic details of the communication between the middle ear and posterior canal ampulla. The temporal bones without these communications did not have clinical histories consistent with the diagnosis of perilymphatic fistula.

Aged↗
PubMedDate not supplied

Early hair cell loss in experimental hydrops.

One, 2, and 4 months after surgical obliteration of the endolymphatic sac, the sequence of degenerative changes in the organ of Corti of the guinea pig was studied. The block surface technique with interference differential (Nomarski) microscopy was used for this investigation to study the morphological changes in the organ of Corti. The hair cell loss was calculated and mapped in cytocochleograms. One month postoperatively a minimal loss of only outer hair cells was observed in the apical cochlear turn. At 2 months a progression of outer hair cell loss was seen, which proceeded in the 4-month group. At 4 months the inner hair cells showed a slight tendency to degenerate, again beginning in the most apical part of the cochlea.

Animals↗