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At least 217 records · Page 12Linked to original sources
PubMed1978

[Vasoactive drugs and oxygen content in the perilymph (author's transl)].

The effect of different vasodilating drugs on the perilymphatic oxygen content in the cat has been examined by means of the polarographic method. The drugs used such as Papaverin, Rheomacrodex, Ronicol, Praxilen and Lasix have had no significant effect on the oxygen concentration in the perilymph. Histamin, 7% Na2CO3 and 50% glycerol have produced a diminution of the perilymphatic oxygen tension. Only angiotensin has produced a 20% rise of the oxygen pressure in the perilymph. This effect is, however, five times smaller than that reached by inhalation of 5% CO2 and 95% O2.

Angiotensin II↗
PubMed1994

[The changes of Ca++ concentrations of endolymph and perilymph of the experimental endolymphatic hydrops].

The changes of Ca++ concentrations of endo- and perilymph were determined by using atomic absorption spectrophotometry in the guinea pig model which endolymphatic sac and duct were surgically obliterated one month ago. The results showed that the Ca++ concentrations of endolymph of hydropic ear was 0.181+0.129 mmol/L (n = 9), and that of the control group was 0.020+0.014 mmol/L (n = 10). The paired t test (P < 0.01) showed significant difference. In perilymph, the concentrations of Ca++ of hydropic ear was 0.679+0.340 mmol/L (n = 10), and that of the control ears was 0.730+0.385 mmol/L (n = 10). The paired t-test (P > 0.05) showed no significant difference. The principle of the increase of Ca++ concentrations in the endolymphatic hydrops was also discussed.

Animals↗
PubMed1995

[Pneumolabyrinth. Radiologic sign of perilymph fistula].

Post-traumatic cochleo-vestibular symptoms can be caused by peri-lymph fistulas, although these cannot be proven preoperatively in most cases by direct clinical examination. A rare case of a traumatic burst fracture of the promotory wall with a consequent perilymph fistula is presented. A preoperative computed tomographic finding of air in the basal turn of the cochlea and superior semicircular canal (pneumolabyrinth) is a reliable sign of perilymph fistula and justifies operative exploration for closure of the fistula. High-resolution computer tomographic imaging of the petrous bones in patients with post-traumatic cochleo-vestibular disturbances is mandatory.

Adult↗
PubMed1977

Perilymph fistulas secondary to gunshot wound. Localization with a radioactive pharmaceutical.

The symptoms, clinical evaluation, routes of formation, and repair of perilymph fistulas are reviewed. We report a case with oval and round window perilymph fistulas secondary to a gunshot wound. A radioactive pharmaceutical was injected into the subarachnoid space in the lumbar area. Subsequent radioactivity was detected at the sites of the fistulas. We discuss the implications and a suggested technique for fistula detection.

Adult↗
PubMedDate not supplied

Perilymph fistulae: variability of symptoms and results of surgery.

A perilymphatic fistula of a labyrinthine window may initially present with various cochlear or vestibular symptoms. Vestibular perilymph leaks can occur spontaneously with or without hearing loss and are most readily diagnosed by a positive Hennebert's sign. Surgical correction is indicated and should initially consist of grafting of the perilymph leak. A significant incidence of recurrence warrants further investigation of grafting materials and techniques.

Adolescent↗
PubMed1975

Isolation of the spirochetes in the perilymph despite prior antisyphilitic therapy: a case report.

For the congenital syphilitic patient to develop sensorineural deafness is uncommon. For the congenital syphilitic patient to have persistence of treponemes after treatment is rare. To demonstrate viable organisms in the inner ear perilymph of the congenital syphilitic patient, despite treatment with penicillin, has not been recorded to date. This is a case report of such a patient.

Adult↗
PubMed1978

Round window niche melanocytes and webby tissue. Possible collateral route of vascular and perilymph circulation.

Two hundred thirteen human temporal bones were studied for characteristics of the round window niche. In 163 specimens melanocytes were found within the attachments of the round window membrane and in the niche, most prominently at the level of the cochlear aqueduct opening. Sixty-two specimens demonstrated discrete webby foci within the lining of the niche, 16 of which completely or partially covered the tympanic surface of the round window membrane, unassociated with fibrous tags or adhesions, and in some cases contained congested vascular channels and melanocytes. The webby foci were sometimes associate; with melanocytes, while melanocytes were present without demonstrable webby foci. These findings may represent a collateral route of vascular or perilymph-related drainage from the inner ear.

Adolescent↗
PubMed1982

Immunologic study on the inner ear. Immunoglobulins in perilymph.

The immunoglobulin composition of perilymph (PL) was measured using electroimmunodiffusion, and transfer of serum antibodies to PL was studied using a passive hemagglutination test in chinchillas and guinea pigs. The mean values of IgG an albumin in PL were two to four times greater than those in CSF. In guinea pigs, IgA was found in 93% of the PL and 32% of the CSF samples, but in chinchillas only trace amounts of IgA were found in 50% of the PL and 15% of the CSF samples. No IgM was detected in PL or CSF of either species. This study suggests that a greater portion of the immunoglobulins in PL probably is derived from perilymphatic blood vessels as a filtrate and that the perilymphatic inner ear immune system is independent from that of the CSF.

Animals↗
PubMed1986

Differential uptake of salicylate in serum, cerebrospinal fluid, and perilymph.

After intraperitoneal administration of salicylate in anesthetized rats and guinea pigs, we found that salicylate levels in perilymph (PL) are closely related to both drug levels in cerebrospinal fluid (CSF) and in serum, with higher levels systematically observed in PL than in CSF. Further analysis suggests that salicylate is not passively transported into PL across CSF but, rather, is transported from blood directly to PL. The time course of salicylate uptake in rats reveals maximum levels at 1 1/2 hours (serum) and two to four hours (CSF and PL). On the other hand, salicylate uptake into serum and CSF of guinea pigs exhibits a longer time course, with maximum levels reached at four hours (serum) and five hours (CSF). These data, not previously available, are basic to our understanding of salicylate-related auditory effects.

Animals↗
PubMed2000

Hearing loss and glutamate efflux in the perilymph following transient hindbrain ischemia in gerbils.

The mechanism underlying ischemia-induced hearing loss was studied in gerbils with transient hindbrain ischemia. Occlusion of the vertebral arteries caused an increase in the concentration of glutamate in the perilymph and elevated the compound action potential (CAP) threshold to 24.6 dB at 5 minutes. the CAP threshold subsequently recovered on reperfusion, gradually reaching 8.3 dB 120 minutes after reperfusion. Under electron microscopy, afferent dendrites of the cochlear nerve in contact with inner hair cells exhibited abnormal swelling 5 minutes after ischemia/reperfusion. These morphological changes were not observed in cochleas treated with an alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)/kainate-type glutamate receptor antagonist, 6-7-dinitroquinoxaline-2,3-dione (DNQX), before hindbrain ischemia; an N-methyl-D-aspartate (NMDA)-type receptor antagonist, D-2-amino-5-phosphonopentanoate (D-AP5), was ineffective. Moreover, the histopathological alterations noted 5 minutes after reperfusion were spontaneously ameliorated 120 minutes after ischemia/reperfusion. These findings suggest that the ischemia-induced increase in extracellular glutamate concentration with subsequent activation of AMPA/kainate receptors is responsible for neurite degeneration and hearing loss in the early stages following transient hindbrain ischemia.

2-Amino-5-phosphonovalerate↗
PubMed1991

On the pathomechanism of cochlear dysfunction in experimental perilymph fistulas.

The mechanism leading to hearing impairment in perilymph fistulas was investigated in guinea pigs with perforated round window membranes (RWM) by analyzing alterations of inner ear fluid pressure, changes of auditory function following manipulations to get presumed air bubbles out of the cochlea ("positional audiometry"), and temporal bone sections. The instantaneous loss of normal positive inner ear fluid pressure after RWM perforation had no immediate effect on auditory function. Inner ear pressure was restored 4 days following RWM perforation. "Positional audiometry" was negative in guinea pigs with perforated RWM. All ears in which auditory thresholds had increased had additional iatrogenic lesions at the spiral lamina. Fistulas in the RWM per se do not affect auditory thresholds. The question of the surgical repair of fistulas was not directly addressed; it only can be concluded that there are no direct sequelae of an isolated fistula which induce auditory impairment and which could be prevented by surgical repair of the fistula.

Acoustic Stimulation↗
PubMed1990

A map of cochlear perilymph protein based on high-resolution two-dimensional electrophoresis.

For systematic characterization of cochlear perilymphatic (PL) fluid proteins and to compare the complex protein mixtures of PL fluid, cerebrospinal fluid (CSF) and blood plasma, we subjected eight postmortem PL fluid samples to two-dimensional (2D) electrophoresis. To avoid contamination of perilymph by blood and blood plasma, the samples were taken immediately after death and analyzed by keeping to certain selection criteria. When compared with CSF, PL fluid in the scala vestibule was found to have an albumin content of approximately 1-2g/l, or 10 times the level of CSF albumin. Due to the small volume of the sample obtained, it was not possible to concentrate the PL fluid. As a result, protein spots in the 2D-gel could only be detected with a highly sensitive silver stain. Visual inspection of the resulting 2D-electrophoretograms showed that most of the "CSF-specific" protein clusters were present in the PL fluid pattern.

Blood Proteins↗
PubMed1983

[Total lactate dehydrogenase activity of perilymph, plasma and cerebrospinal fluid in unstressed and noise stressed guinea pigs].

The total activity of lactate dehydrogenase (LDH) of perilymph (PL), plasma, and cerebrospinal fluid (CSF) of unexposed and sound-exposed guinea pigs was examined with due consideration of the principal sources of error. To test the purity of PL samples, protein, potassium, and sodium were determined simultaneously (Table 1). The LDH was analysed fluorometrically. It was found that there are considerable differences in the LDH activities of PL, CSF, and plasma (Table 2). The mean activity of PL was three to four times higher than that of CSF and only about half that of plasma. No significant difference was found between the PL in scala tympani and scala vestibuli. The most frequent LDH values of the individual fluids (Fig. 2) were somewhat lower than the mean values calculated. Immediately (less than or equal to 60 min) after exposing the animals to wide-band noise at an intensity of 140 dB SPL for 10 min, the mean PL values of the scala tympani and scala vestibuli were found to be somewhat higher than in unexposed animals (Table 3). Eighteen hours after the exposure, slightly higher activity was only detectable in PL of the scala vestibuli. The differences were not found to be significant. The LDH values of CSF and plasma remained unchanged both less than or equal to 60 min and 18 h after noise exposure.

Animals↗
PubMed1980

Endocochlear potential and potassium concentration in endolymph and perilymph of the chinchilla.

Guinea pigs and chinchillas were studied for EP and potassium concentrations in scala media and scala tympani using potassium-sensitive microelectrodes. Response of EP to 3 min anoxia was strikingly different in these two species. On the other hand, the resting values for EP and potassium concentrations in endolymph and perilymph were not significantly different. These findings suggest that the different response to anoxia in these two species is due to differences in permeability of the cochlear partitions to the ions.

Animals↗
PubMed1976

[Comparative studies of lactate concentration in the perilymph, blood and cerebrospinal fluid of normal and sound exposed guinea pigs (author's transl)].

The paper deals with comparative studies of lactate concentration in the perilymph (PL) of scala tympani and of scala vestibuli, arterial and venous blood, serum and cerebrospinal fluid (CSF) of normal and sound exposed guinea pigs, special consideration having been given to possible sources of error in the methods employed. Lactate was determined enzymatically using a micromodification of the Boehringer UV-test combination adapted to 1 mul PL. The lactate concentrations in the PL of scala tympani and scala vestibuli did not differ significantly. The mean values amounted to 4.5-5.2 mM/l in the case of the opened and of the unopened subarachnoid space (Table 1). The lactate concentrations in the PL of both cochlea scales were significantly higher already ten minutes post-mortem. In the exposure experiments the animals were unilaterally exposed to sound for 1 h in an acoustically isolated system using a wide-band noise at an intensity of 120 dB SPL for one series and 2-kHz pure-tone at intensities of 112 and 122 dB SPL for two other series. We did not detect any changes in the lactate concentrations neither in the PL nor in the blood and in the CSF, following sound exposure (Table 2 and 3). The lactate concentrations of arterial and venous blood and CSF did not differ significantly. The mean values amounted to 1.4-1.8 mM/l (Table 2). However, if blood was not deproteinized or centrifuged immediately after being taken, the lactate concentration increased markedly. A comparison of the present results has shown that the lactate concentration in the PL is about three times as high as in blood and in CSF. This difference in concentration suggests that the PL lactate is of intracochlear origin and that glycolytic processes take place in the inner ear also under normal conditions. Systematic studies of additional metabolic parameters must be conducted before a definitive physiological interpretation of the present analytical results can be given.

Animals↗
PubMed1981

[On the glucose, pyruvate, and lactate concentration of perilymph, blood, and cerebrospinal fluid of unexposed and sound-exposed guinea pigs under ethyl urethane anesthesia (author's transl)].

Glucose, pyruvate, and lactate of perilymph (PL), blood, and cerebrospinal fluid (CSF) of unexposed and sound-exposed guinea pigs under ethyl urethane anesthesia were examined with due consideration of the principal sources of error. The animals had fasted for 15--20 h before the experiment to stabilize the blood glucose level. The metabolites were determined enzymatically by means of fluorescence measurements. It was found that the glucose levels depend not only on ingestion but also on the duration of anesthesia of the animals before sampling. The mean values of the scala tympani and scala vestibuli PL and CSF did not differ significantly, being about half those of blood or plasma immediately (10--20 min) after introducing anesthesia (Table 2). This concentration difference is in disagreement with the original ultrafiltration hypothesis of PL, suggesting a blood-PL barrier for glucose. The dependence on the duration of anesthesia and on the animals' ingestion before sampling appears to be an important cause of the differences in glucose data published in literature hitherto. No influence of anesthesia on pyruvate and lactate concentrations was observed. Data obtained on unexposed control animals (Tables 3 and 4) confirmed our earlier metabolite findings (Scheibe et al. 1976, 1981). No major changes in glucose, pyruvate, and lactate concentration of PL, blood, and CSF were detectable immediately after 1 h of exposure to wide-band noise at an intensity of 120 dB SPL. The present lactate findings confirmed our earlier exposure experiments (Scheibe et al. 1976), but they did not agree with the information given by Schnieder (1974).

Animals↗
PubMed1981

[Lactate and pyruvate concentrations in perilymph, blood, and cerebrospinal fluid of guinea pigs].

Lactate and pyruvate were studied comparatively in perilymph (PL), blood, and cerebrospinal fluid (CSF) of anesthetized guinea pigs. Arterial blood pressure, heart and respiration rate (Fig. 1), and arterial blood-gas state (Table 2) were simultaneously checked in a group of the animals. The metabolites were determined enzymatically by using the fluorometric technique. The studies have shown (Table 1) that both the lactate and the pyruvate concentrations are in PL at a similar rate (about 3:1) higher than in native blood and also higher than in CSF. The metabolite values of blood, especially the lactate values, were lower when blood was taken alone, e.g., more physiological, than in the case when CSF and PL had been sampled before. The lactate/pyruvate ratios of Pl are somewhat higher than the blood ratios. The ratio of CSF was found to be lower. The high metabolite levels in PL suggest an intracochlear origin. A direct perilymphatic lactate origin could not be detected.

Animals↗
PubMed1985

Modulation of activity in starling cochlear ganglion units by middle-ear muscle contractions, perilymph movements and lagena stimuli.

In the present study three groups of cochlear ganglion neurons were detected which differed in respect to their tone-evoked and spontaneous activity: auditory units which showed an irregular spontaneous discharge, non-auditory neurones with regular activity and such with an irregular spontaneous discharge pattern. Electrically-elicited contractions of the middle-ear muscle influenced the tone-evoked and/or the spontaneous activity of the auditory and the non-auditory neurones with irregular spontaneous discharge but not, however, the regularly firing units. Similar results were obtained with imposed perilymph movements in the cochlea (evoked via the vestibular system. Fractions of all three groups of cochlear ganglion neurones were responsive to direct deformations of the membraneous lagena. Several (auditory and non-auditory) units with irregular discharge were excited during a basilar membrane displacement towards scala vestibuli whereas a basilar membrane motion towards scala tympani resulted in a decrease of the discharge rate. A few units showed a different reaction. The results provide evidence that the neurones with periodic spontaneous discharge innervate the lagena and that this sense organ has no auditory significance in birds. The peripheral origin of the 'non-auditory' neurones with irregular spontaneous activity remains undecided and might be the macula lagenae or the apical portion of the basilar papilla.

Action Potentials↗