Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Perilymph”

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 37 records · Page 2Linked to original sources
PubMed1991

Identification of perilymph proteins by two-dimensional gel electrophoresis.

Perilymph has a total protein component that is quantitatively distinct from serum and cerebrospinal fluid (CSF). The goal of this research was to determine if perilymph contains any qualitatively unique protein constituents that will distinguish it from serum or CSF. To test this hypothesis, matched sets of perilymph, serum, and CSF were obtained from 18 guinea pigs and seven human subjects. The purity of each sample was assured by measurement of the protein concentration of each sample and comparison of this parameter to known normal values for perilymph, serum, and CSF. Each sample was then subjected to two-dimensional gel electrophoresis, separating proteins by isoelectric point in the horizontal dimension and by relative molecular weight in the vertical dimension. All gels were processed under precisely identical physical conditions by use of a diamine silver stain. A small number of perilymph proteins not found in plasma were identified in both the guinea pig and the human specimens. The finding of unique perilymph proteins may permit the development of a sensitive marker that will aid in the diagnosis of perilymph fistula.

Animals↗
PubMedDate not supplied

Peptides of the otosclerotic perilymph examined by analytical isotachophoresis.

Perilymphs of normal and otosclerotic origin were separated chromatographically on a Sephadex G-25 microcolumn. Peptide composition of the perilymphs was compared by capillary analytical isotachophoresis in the molecular mass range 0.3-5 kD. Otosclerotic perilymph samples contain a heterogeneous, UV-absorbing peptide subfraction which is not detected in the normal perilymph. Normal and otosclerotic perilymph, furthermore, contain four common subfractions detected in twice the normal concentration in the otosclerotic perilymph. These ITP subfractions are degraded during acid hydrolysis (6 M HCI). On the contrary, otosclerosis is a deficient state compared with the normal, as the number of peptides or oligoglycopeptides is twice as high in normal as in otosclerotic perilymph, beside the otosclerosis specific peptides.

Electrophoresis↗
PubMed1991

Effects of perilymph volume adjustments on cochlear blood flow in the guinea pig.

Previous research suggests a potential relationship between perilymphatic pressure (Pp) and cochlear blood flow (CBF); however, the alterations in Pp necessary to produce changes in CBF have not been adequately described or quantified. The effects of perilymph volume changes on systemic blood pressure (BP) and CBF were presently investigated in the guinea pig cochlea. Five microliters of perilymph were displaced in each of three conditions: viz. evacuation of 5 microliters from the cochlea; replacement of these 5 microliters; and finally the addition of 5 microliters of artificial perilymph into the cochlea. All perilymph volume adjustments were completed in 1-microliter increments during which changes in CBG and BP were recorded. Significant alterations in CBF were observed during 1-microliter perilymph volume adjustments in each condition with no significant changes in systemic BP. The results from this study support our hypothesis that an inverse relationship exists between CBF and Pp in that decreases in perilymph volume yielded elevations in CBF while increases in perilymph volume yielded reductions in CBF.

Animals↗
PubMed1999

Beta-2 transferrin assay in the identification of perilymph.

HYPOTHESIS: Western blot assay for beta-2 transferrin protein is a clinically useful method for the detection of human perilymph and should be used for the diagnosis of perilymph fistulas (PLFs). BACKGROUND: Considerable controversy exists regarding the diagnosis of PLF. Recent studies suggest that the detection of beta-2 transferrin protein may be useful in the identification of perilymph. METHODS: To evaluate the usefulness of the beta-2 transferrin assay for identifying human perilymph, paired perilymph samples and negative controls were collected on Gelfoam pledgets from 20 patients who had surgery that opened the inner ear. Blinded immunoelectrophoretic assay (Western blot) for beta-2 transferrin was performed on each specimen. RESULTS: Only one (5%) of the known perilymph samples and none of the control specimens were definitely positive for beta-2 transferrin. Combined with historical data, this assay has 29% sensitivity, 100% specificity, 100% positive predictive value, and 31% negative predictive value. CONCLUSIONS: These findings suggest that the beta-2 transferrin protein assay may not be a reliable method for detecting human perilymph when performed using this technique.

Cochlear Aqueduct↗
PubMed2003

Prophylactic effect of Ca2+ -deficient artificial perilymph perfusion on noise-induced hearing loss.

OBJECTIVE: To investigate the prophylactic effect of low calcium concentration perilymph on noise-induced hearing loss. METHODS: Forty guinea pigs with normal hearing weighing 250-350 g were assigned to five groups (8 in each group): (1) Ca(2+)-deficient perilymph perfusion (CDP) for 2 h; (2) white noise (120 dB SPL) exposure (WNE) only for 1 h, (3) combination of calcium-deficient perilymph perfusion and white noise (120 dB SPL) exposure (WNE + CDP); (4) normal artificial perilymph (NAP) perfusion for 2 h; and (5) white noise exposure + normal artificial perilymph perfusion (WNE + NAP) for 2 h. Compound action potentials (CAP) evoked by click was recorded from round window every 15 min. The cochleae from 5 animals in each group were examined with scanning electron microscope. RESULTS: The CAP for group 1 experienced a threshold shift (TS) of 15-26 dB, while group 2 yielded a 46-59 dB TS and group 3 a 37-45 dB TS; no threshold shift occurred in group 4. The CAP TS in group 5 was 33-64 dB. The CAP TS of group 3 was less than that of group 2. After one hour of noise exposure, the CAP TS of group 3 were 45.92 +/- 2.90 dB and 59.30 +/- 3.95 dB in group 2. There were significant differences (P < 0.05) between groups 3 and 2. The CAP TS of group 3 was less than that of group 5 at the points of 1, 1.5 and 2 h after noise exposure. There was a significant difference between groups 3 and 5 (P < 0.01). Stereocilia of 89 OHC(3) were in disarray in five cochleae after noise exposure in group 2. The cuticular plates of 8 OHC(2),3 sank and the stereocilia became fused in only one animal cochlea after noise exposure in group 3 combined with low calcium perilymph perfusion. CONCLUSIONS: Low calcium concentration appears to participate in preventing noise-induced hearing loss and the rising of calcium concentrations in inner hair cells after noise exposure, which may have been due to the opening of calcium channels in inner hair cells during noise exposure. The mechanism of the prophylactic effect might be caused by a lower calcium concentration in inner hair cells in the cochlea attenuating the influence of noise exposure on hearing loss; calcium deficient perilymph perfusion prevented calcium accumulation in inner hair cells of the cochlea. The motility of the OHCs might be partially inhibited by low calcium concentration that reduced noise-induced hearing loss in turn.

Action Potentials↗
PubMed1985

[Sisomycin pharmacokinetics in the perilymph and blood serum--an approach to predicting its ototoxic effect].

To elucidate the possibility of predicting the level of aminoglycoside antibiotic penetration into the fluids of the internal ear by the antibiotic blood levels, the pharmacokinetics of sisomicin in the perilymph and blood serum was studied on guinea pigs. The antibiotic was administered to the animals subcutaneously in doses of 50, 100 and 200 mg/kg. On the basis of the comparison of the sisomicin concentrations in the perilymph normalized against the dose it was concluded that the pharmacokinetics of sisomicin in the perilymph and blood serum of the animals was linear. Comparison of the areas under the curves of the antibiotic concentration versus time in the perilymph (AUCp) and blood serum (AUCs) showed that the tissue availability of the antibiotic in this study characterized by its penetration into the perilymph and defined by the ratio of the AUCp to AUCs amounted to 55 per cent. In a two-compartment model it was not possible to predict the antibiotic levels in the perilymph by concentrations in the blood. However, by the antibiotic blood levels it was possible to characterize in a complex the pharmacokinetic behaviour of the antibiotic in the perilymph by predicting the areas under the respective curves of the antibiotic concentration versus time. The proportional relation between the values of the AUCp and AUCs suggested that the level of the antibiotic penetration into the internal ear and consequently the intensity of the potential ototoxic effect could be more reliably predicted not by separate values of the antibiotic concentration but by the areas under curves of aminoglycoside concentrations versus time.

Animals↗
PubMed1990

A patient-oriented approach to perilymph fistula.

The subject of perilymph fistula is controversial in part because the preoperative diagnosis of perilymph fistula is difficult. Patients suffering auditory and vestibular symptoms secondary to perilymph fistula, therefore, present a dilemma to the practicing physician. In some instances, patients with auditory and vestibular symptoms in the absence of perilymph fistula will be subjected to middle ear exploration without benefit, while in other instances patients with auditory and vestibular symptoms secondary to perilymph fistula will be denied surgical treatment. Auditory and vestibular symptoms are a quality of life issue. Therefore, in an effort to provide care of the highest quality the patient must be actively involved in the decision process. Such involvement can be meaningful only after the patient is carefully counseled as to the pros and cons of surgery, as well as the alternatives. A prognostic paradigm based on the personal experience of one of us (W.L.M.) with perilymph fistula patients is described and is used in patient consultation in an effort to facilitate decision making.

Fistula↗
PubMed1980

Permeability to potassium of the endolymph-perilymph barrier and its possible relation to hair cell function.

The endocochlear potential and potassium concentrations in endolymph and perilymph were simultaneously measured in the basal turn of the guinea pig cochlea with double-barreled K+ selective electrodes. The K+ conductance and K+ permeability coefficient of the endolymph-perilymph barrier were calculated from the rate of change of endolymph K+ concentration relative to the K+ electrochemical potential difference recorded during permanent anoxia. When anoxia was induced in guinea pigs treated with kanamycin, the rate of decline of the electrochemical potential difference for K+ between the endolymph and perilymph was reduced when compared to normal guinea pigs. In guinea pigs exposed to broad band noise at 115 dBA for periods from 11-15 days, the rate of decline of the electrochemical potential difference for K+ across the endolymph-perilymph barrier was reduced but not to the extent found in guinea pigs treated with kanamycin. The K+ conductance and K+ permeability coefficient of the endolymph-perilymph barrier showed substantial decreases in noise exposed and kanamycin treated guinea pigs, as compared to normal guinea pigs. The magnitude of decrease of K+ permeability of the endolymph-perilymph barrier by noise or kanamycin was correlated with suppression of the maximum output of the cochlear microphonic.

Animals↗
PubMed2001

[Permeability of the round window membrane for prednisolone-21-hydrogen succinate. Prednisolone content of the perilymph after local administration vs. systemic injection].

BACKGROUND AND OBJECTIVE: Prednisolone is the drug of first choice for the treatment of cochleovestibular disorders, such as sudden hearing loss. Because of the known side effects, the efficient drug levels to be achieved within inner ear fluids are limited by intravenous administration. The aim of the study was to determine the concentration in the perilymph of prednisolone-21-hydrogen succinate applied into the round window niche in comparison to the concentration after intraperitoneal application. METHODS: Application of prednisolone-21-hydrogen succinate (5 mg in 0.1 ml) on the round window membrane was performed after sedation under microscopic view directly into the round window niche of the guinea pig. In order to compare the results, perilymph samples after systemic application of 60 mg/kg body weight prednisolone were used. The time between application and taking specimens of perilymph from the cochlea varied. Specimens of perilymph were obtained after 15, 20, 80, 180, 330, and 960 min (10 specimens in each group, n = 60) by dissecting the cochlea and opening the apex cochleae. Levels of prednisolone-21-hydrogen succinate in perilymph were measured by isocratic high-pressure liquid chromatography (HPLC). RESULTS: The highest levels of prednisolone-21-hydrogen succinate were found after 180 min: 952.3 mg/l (95% confidence interval: 382.7). After 960 min the level was 18.72 mg/l (95% confidence interval: 16.9). In the group with systemic application, the levels measured were below 14.71 mg/l (95% confidence interval: 7.05). CONCLUSION: The results demonstrate that high levels of prednisolone-21-hydrogen succinate in perilymph are achievable by local application of a single dose into the round window niche. After application of 5 mg, the levels of prednisolone are measurable up to 16 h.

Administration, Topical↗
PubMed2006

Demonstration of a longitudinal concentration gradient along scala tympani by sequential sampling of perilymph from the cochlear apex.

Local applications of drugs to the inner ear are increasingly being used to treat patients' inner ear disorders. Knowledge of the pharmacokinetics of drugs in the inner ear fluids is essential for a scientific basis for such treatments. When auditory function is of primary interest, the drug's kinetics in scala tympani (ST) must be established. Measurement of drug levels in ST is technically difficult because of the known contamination of perilymph samples taken from the basal cochlear turn with cerebrospinal fluid (CSF). Recently, we reported a technique in which perilymph was sampled from the cochlear apex to minimize the influence of CSF contamination (J. Neurosci. Methods, doi: 10.1016/j.jneumeth.2005.10.008 ). This technique has now been extended by taking smaller fluid samples sequentially from the cochlear apex, which can be used to quantify drug gradients along ST. The sampling and analysis methods were evaluated using an ionic marker, trimethylphenylammonium (TMPA), that was applied to the round window membrane. After loading perilymph with TMPA, 10 1-muL samples were taken from the cochlear apex. The TMPA content of the samples was consistent with the first sample containing perilymph from apical regions and the fourth or fifth sample containing perilymph from the basal turn. TMPA concentration decreased in subsequent samples, as they increasingly contained CSF that had passed through ST. Sample concentration curves were interpreted quantitatively by simulation of the experiment with a finite element model and by an automated curve-fitting method by which the apical-basal gradient was estimated. The study demonstrates that sequential apical sampling provides drug gradient data for ST perilymph while avoiding the major distortions of sample composition associated with basal turn sampling. The method can be used for any substance for which a sensitive assay is available and is therefore of high relevance for the development of preclinical and clinical strategies for local drug delivery to the inner ear.

Animals↗
PubMed1992

Protein profiles of perilymph and endolymph of the guinea pig.

Results of protein separation of guinea pig plasma, perilymph, and endolymph by means of high-resolution two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis are presented. Several proteins are present in perilymph at levels in basic accord with the total protein gradient with respect to plasma; however, others are present in perilymph at levels comparable to plasma levels, and one protein low molecular weight protein, PLS:33, is eight times higher. In addition, a high molecular weight protein is shown to be present at similar levels in the two compartments. These findings indicate that ultrafiltration cannot be the sole mechanism of perilymph production. Endolymph proteins are uniformly five to eight times lower than perilymph levels, essentially following the total protein concentration gradient between the two compartments. This supports the view that endolymph is derived from perilymph rather than directly from blood.

Animals↗
PubMed1991

Evidence that amikacin ototoxicity is related to total perilymph area under the concentration-time curve regardless of concentration.

Previous studies have failed to fully establish whether ototoxicity is related in any way to the levels of an aminoglycoside antibiotic in the perilymph. To study this we exposed guinea pigs to continuously infused amikacin at four different dosing rates under conditions parallel to those used in our previous study which related ototoxicity to total plasma area under the concentration-time curve regardless of the level in plasma. It was found that at all dosing rates, levels in the perilymph and ratios of levels in perilymph/plasma remained constant as the dosing duration increased from nonototoxic to strongly ototoxic. Plasma and perilymph amikacin levels were found to be linear functions of the dosing rate even at ototoxic dosing exposures, and ratios of levels in perilymph/plasma did not differ between dosing rates. The total perilymph area under the concentration-time curve was not different between dosing rates either for a total dose associated with threshold ototoxicity or for one associated with severe ototoxicity. The results suggest that amikacin ototoxicity is related to the integral of the concentration in the perilymph over the total time of amikacin exposure regardless of the level in the perilymph.

Amikacin↗
PubMed1982

K, Cl, and H2O entry in endolymph, perilymph, and cerebrospinal fluid of the rat.

The kinetics of radioactive potassium, chloride, and water entry into endolymph, perilymph, and cerebrospinal fluid were studied after intravenous administration of tracers in anesthetized and nephrectomized rats. Samples of cochlear endolymph, perilymph of scala vestibuli, perilymph of scala tympani, and cisternal cerebrospinal fluid were obtained. The data showed: 1) a rapid turnover of water in endolymph, perilymph, and cerebrospinal fluid, since 3H2O equilibrated with plasma in a few minutes; 2) a slow entry of 42K and 36Cl in perilymph, since 36Cl equilibrated with plasma after 2 h and 42K did not at 6 h; 3) an extremely slow entry of 42K and 36Cl in endolymph, since no equilibrium with plasma was obtained within the 5 h of the experiments. The comparison of the compartmental analysis of our data with the results of other studies using perilymphatic perfusion of tracers indicated that perilymph rather than plasma may be considered as the precursor of endolymph.

Animals↗
PubMed1976

Quantitative assessment of perilymph sources.

The problem of the perilymph origin--influx of cerebrospinal fluid (CSF) versus ultrafiltration within the cochlea--cannot be solved by mere qualitative proofs of tracer passage through the cochlear aqueduct. In order to gain quantitative data on the possible perilymph sources, an experimental study was designed to follow the time course of dye concentrations in the cisternal CSF and in the perilymph after tracer injection into the CSF at the vertex. By comparing the resulting concentration peaks in both fluids, the mean peak of the perilymph tracer concentrations was found to reach 36% of the maximum CSF concentration only. It is concluded that the local perilymph production within the cochlea exceeds the influx of CSF by a ratio of about 2:1. A working hypothesis of the double perilymph origin is discussed.

Animals↗
PubMed1979

Elimination kinetics of furosemide in perilymph and serum of the chinchilla. Neuropharmacologic correlates.

This study was done to determine the comparative elimination kinetics of furosemide from chinchilla perilymph and serum, and to correlate perilymph concentration with changes in endocochlear potential. The elimination kinetics of furosemide (FU) were determined in sera and perilymph obtained from chinchillas injected with 100 mg/kg i.v. of FU. Concentrations of FU exhibited a linear decay pattern in serum and perilymph over the initial 60 minutes. The rate of decline of furosemide levels in perilymph was about four times slower than the rate of fall in serum. Chronic treatment (25 mg/kg i.p. every 12 hours) did not appear to influence the level of drug at 60 minutes after a dose of FU (100 mg/kg IV). Chinchillas were also studied following doses of FU ranging from 25--200 mg/kg i.v. to see the effect on endocochlear potential (EP). A positive correlation was found between FU dosage, the maximum millivolt reduction of EP and the time to initiation of recovery of EP. The perilymph concentration of furosemide when the EP began to recover was 5 microgram/ml (1.5 x 10(-5) M). Knowledge of furosemide kinetics may ultimately be applied to prevent ototoxicity in patients.

Animals↗
PubMed1990

[Transmission of changes in the external ear atmospheric pressure to the perilymph].

Using guinea pig, pressures in the external ear canal, in the middle ear and in the perilymph were registered simultaneously, while pressure was applied to the external ear canal using an impedance audiometer. In the first experiment, applied pressure was changed in the range from 200 mmH2O to -200 mmH2O with and without the opening of the otic bulla. The change in the perilymphatic pressure with the opening was smaller than that without the opening. The result indicates that the external ear pressure is transmitted to the perilymph not only via the ossicular chain but also via the middle ear cavity without the opening, while it is exclusively transmitted via the ossicular chain with the opening. Pressure transmission to the perilymph was significantly impaired either by disrupting the ossicular chain or by closing the round window niche, especially by the latter. Thus the middle ear cavity itself plays an important role in pressure transmission from the external ear canal to the perilymph mainly via the round window. In the second experiment, applied pressure to the external ear canal was changed in the range from 1000 mmH2O to -1000 mmH2O after the Eustachian tube being closed. Between 400 mmH2O and -200 mmH2O, the middle ear and perilymphatic pressures paralleled well with the applied pressure. Beyond these levels, the middle ear pressure increased or decreased in response to the applied pressure but the perilymphatic pressure reversed against the middle ear pressure. Communication between perilymph and cerebrospinal fluid via the cochlear aqueduct is thought to be a major factor causing this reversal which, in turn, aggravates pressure gradient between the middle ear and the perilymph.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

[Determination of IL-6 in serum and perilymph during inner ear immune response].

During secondary inner ear immune responses against keyhole limpet hemocyanin (KLH), to understand the change of interleukin-6 (IL-6) levels in perilymph and serum, IL-6 levels in perilymph and serum were investigated using an immunoassay. No IL-6 levels were detectable at Day 0 in perilymph. The earliest perilymph IL-6 levels were observed after 6 h, peaking at 24 h, and then decreasing gradually. IL-6 level remnants were detected at 7 days in perilymph. In contrast, during this observation period, low IL-6 levels were only detectable in perilymph from control ears, disappearing after 72 h. IL-6 levels don't change in serum. Previous study has identified the endolymphatic sac (ES) lags behind the earlier appearance of intercellular adhesion molecule-1 (ICAM-1) in the spiral modiolar vein and spiral ligament during immune response. The present study not only provides further support for the existence of an inner ear immune response which is regulated by cytokines, but also supports that cytokines controlling expression of adhesion molecules are released probably by cells which located out of ES.

Adjuvants, Immunologic↗
PubMed1992

Effect of exogenous arachidonic acid metabolites applied on round window membrane on hearing and their levels in the perilymph.

Our previous studies revealed that treatment with sodium salicylate or indomethacin caused hearing loss, a decrease in prostaglandin (PG) levels, and an increase in leukotriene (LT) levels of the arachidonic acid (AA) cascade in the perilymph. We suspected that decreased PG-levels and/or elevated LT-levels in the inner ear may be responsible for the salicylate ototoxicity. In order to test this hypothesis, effects of exogenous treatments with PGs, PG-analog, LTs, and other lipoxygenase products on hearing and levels of AA metabolites in the perilymph were studied in chinchillas. Cyclooxygenase products, PGI2, 6-keto-PGF1 alpha, Iloprost (PGI2 analog), PGE2, and LTB4, LTC4, and 15-hydroxyeicosatetraenoic acid (15-HETE) in the lipoxygenase products in the dose of 150 ng were applied on the round window membrane (RWM); cochlear function tested by auditory brainstem response (ABR) and samples of perilymph were collected at 0.5, 1, 2, and 4 hours after the application. Samples of perilymph were assayed for all spectra of AA metabolites by high performance liquid chromatography (HPLC) and radioimmunoassay (RIA). PG-treated animals developed minimal or no hearing loss. LT-treated animals exhibited hearing loss of 20 to 40 dB, peaking at one hour after the treatment. Elevated levels of arachidonic acid metabolites were measured in the perilymph of the ears treated with respective AA metabolites, with peak levels at one hour from the application. The findings of this study indicate that hearing loss can be induced by altered levels of PGs or LTs in the perilymph. This is another strong evidence that salicylate induced ototoxicity can be mediated by abnormal arachidonic acid metabolism in the inner ear.

Animals↗