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At least 919 records · Page 51Linked to original sources
PubMed1976

Effects of anoxia and ethacrynic acid upon ampullar endolymphatic potential and upon high energy phosphates in ampullar wall.

The ampullar endolymphatic potential (AEP) was studied in the guinea pig during ischemia and asphyxia and following systemic application of ethacrynic acid. In addition the specialized and nonspecialized portions of the ampullar wall were analyzed for ATP and P-creatine at different conditions of metabolic interference. Under control conditions the AEP amounted to + 4.6 +/- 1.2 mV. In both types of hypoxia the decline of the AEP proceeded on a much slower time scale than that of the cochlear endolymphatic potential (CEP), and the maximum negativity reached was considerably less. Quantitative analysis of both types of ampullar wall tissue indicated a much slower decline in hypoxia of ATP levels than in the stria vascularis. Changes in P-creatine levels were considerably more rapid. The AEP became reduced and changed polarity also by intoxication with ethacrynic acid (EA), but higher dosages (above 70 mg/kg) were necessary than for effects upon the CEP and much longer time periods were required for attainment of maximum negativity. The maximum negativity of the AEP was significantly greater at a dosage of 100 mg/kg of EA than during ischemia. At the point of maximum depression of the AEP P-creatine levels in both types of ampullar tissue were unchanged, but ATP levels were significantly reduced in the specialized portions of ampullar wall.

Action Potentials↗
PubMed1976

The effect on perilymph of the alteration of serum glucose or calcium concentration.

In the experimentally-induced hyper- or hypoglycemic state, perilymph glucose concentration paralleled the blood concentration, although a delay of about one hour was observed between the time of maximum concentration of glucose in perilymph and its concentration in blood. In hypercalcemia, perilymph calcium concentration steadily increased over a three-hour period, although blood calcium concentration fluctuated during this time. After an initial increase in the CSF calcium concentration, there were insignificant changes during the second and third hours. In animals with thyrocalcitonin-induced hypocalcemia, although blood calcium concentration steadily decreased, its concentration in perilymph and CSF remained practically constant. The present findings suggest that the chemical composition of perilymph can be altered by changing the blood concentration of glucose or calcium. The marked difference of behavior noted between glucose and calcium in these experiments would indicate the existence of different mechanisms for maintaining the homeostatic state for these two substances.

Animals↗
PubMed1976

Endolymphatic sac drainage for intractable vertigo (method and experiences).

This paper describes a method of endolymphatic sac decompression and drainage. The method emphasizes widely exposing dura, avoiding skeletonization of the posterior semicircular canal and draining the sac via a T tube. The results of this procedure in 75 patients, including statistics in 46 ears are discussed. In patients with unilateral disease good results were obtained in control of vertigo in 94 percent of patients and significant improvement in cochlear function in over 30 percent.

Drainage↗
PubMed1976

An experimental model for the study of endolymphatic hydrops in sharks: implications for the clinician.

In recent years, attention has focused on the role of the endolymphatic sac (ELS) and the endolymphatic duct (ELD) in the pathogenesis of endolymphatic hydrops (ELH). Changes have been noted surgically and radiographically by others in the ELS and ELD in patients with ELH. This report summarizes the development of a shark model with which to study the pathophysiology of ELH. The background material and overall results of anatomic, histopathologic, and ultrastructural studies using the model are presented. Possible implications for the clinical handling of ELH as a result of this work is emphasized.

Animals↗
PubMed1977

Stapedectomy--fistula repair.

Perilymphatic fistulae have been proposed to occur most frequently on the short side of the graft in stapedectomized patients. The usual recommendation in fistula cases has been replacement of the entire prosthesis by a piston and tissue graft complex. In this case the stapedectomy had been performed, using a polyethylene Shea strut, 15 years previously. The air-bone gap had been closed during this entire period. A fistula was suspected after sudden hearing loss developed after barotrauma. At the time of exploratory tympanotomy, a fistula was noted on the long side of the oval window graft. It was elected to leave the polyethylene tube prosthesis in place because of its solid fixation, both laterally and medially. The fistula was closed by subcutaneous tissue graft.

Adult↗
PubMed1977

Endolymphatic sac surgery.

There is a disturbing variation in the reported success rate in Endolymphatic Sac Surgery in the literature. Relatively long-term (24 months to 10 years) follow-ups are given in a series of 66 patients in this paper. Results reveal only a 55% long-term relief of vertigo in these patients. Only 30% of this series of cases had any improvement in cochlear function. There was a definite trend towards recurrence of vertigo in the longer follow-up cases. It is concluded that Endolymphatic Sac Surgery still is important in the treatment of idiopathic endolymphatic hydrops, but is of questionable value early in the course of the disease. Total removal of the endolymphatic system remains the best single surgical approach in a large number of patients with Ménièr's disease.

Adult↗
PubMed1979

Endolymphatic hydrops and otitis media.

Clinical observation of patients with fluctuant sensorineural hearing loss following or occurring with chronic otitis media led to the hypothesis that endolymphatic hydrops can result from chronic otitis media. Illustrative case reports are described. This hypothesis resulted in a temporal bone study of 560 cases in which 109 temporal bones demonstrated the presence of hydrops and 194 evidenced otitis media. Seventy-five cases demonstrated both otitis media and hydrops, of which 20 cases were selected for more detailed histopathological study. An interesting finding was the presence of apical hydrops in every case of the latter group. Statistical interpretation of this data helped rule out a coincidental or chance occurrence. A discussion of this clinical relationship included the significance of subclinical (silent) otitis media as a possible cause of endolymphatic hydrops.

Adult↗