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Cerebrospinal fluid and acoustic neurinoma specific proteins in perilymph.

White rabbits were immunized with pooled and concentrated cerebro-spinal fluid (CSF) and with tumour homogenate concentrate from specimens taken from five patients with acoustic neurinoma. The absorbed anti-CSF-antitumour antiserum was tested with the micro-immunodiffusion test against normal human serum (NHS), CSF, perilymph and CSF from tumour patients and tumour homogenate. NHS showed no precipitates in any of the tests. One protein band was observed in all the other four reactants. Tumour tissue and perilymph had two proteins in common. Diffusion from the CSF space into the perilymph can thus occur via both the cochlear aqueduct and the internal acoustic meatus.

Cerebrospinal Fluid Proteins↗

The perilymph fistula syndrome defined in mild head trauma.

Neurological and neuro-otological studies were carried out on 102 adults with mild cranio-cervical trauma productive of positional vertigo and perilymph fistula as confirmed by laboratory tests, and by the finding of perilymph fistula at tympanotomy in the surgically managed group. In this patient group, all other neurological and neuro-otological diagnoses were excluded, e.g. epilepsy, cerebral palsy, multiple sclerosis, retardation; and for the neuro-otological group those with a history of ototoxicity, labyrinthitis, Meniere's disease, chronic ear infections, or developmental or familial disorders. Emphasis in this study was on mild trauma: fewer than half of the sample had been rendered unconscious in the injury of record, and a third of the cases were of whiplash type, with no loss of consciousness (LOC) and no remembered headstrike. These concomitant lesions comprise the perilymph fistula syndrome (PLFS) with a unique profile of neurological, perceptual, and cognitive deficits resembling a post-concussion injury. A complete description of the clinical picture is given, including psychological, cognitive and diagnostic tests, and the outcome of bedrest vs. surgical management. PLFS can arise from minor trauma, fistula are frequently bilateral (71/102), a mild sensorineural hearing loss is of variable occurrence (53%), secondary hydrops is not uncommon, and women appear more vulnerable than men for developing the syndrome. As based upon combined laboratory techniques and clinical symptomology, fistula were correctly predicted in 61 of 65 laser-operated ears. The positional vertigo component of PLFS was in all cases managed according to a special physical therapy program utilizing exercises for vestibular symptom habituation. Even when diagnosed late, a good-to-excellent outcome was achieved in 70% of treated patients.

Adult↗

Effect of glycerol on electrochemical composition of endolymph and perilymph in the rat.

Glycerol (2 g/kg body weight), or 0.15 M NaCl for control animals, was administered to rats by i.v. injection. The dose was chosen in order to obtain an osmolarity increase in plasma of about 15 mosm/l 1 h after the glycerol administration, an increase which is similar to that observed in the human glycerol dehydration test. Endolymph and perilymph were sampled from the basal turn of the cochlea; cerebrospinal fluid (CSF) was sampled from cisterna magna. Plasma osmolarity, endocochlear potential, Na and K concentrations in endolymph, perilymph and CSF were determined 1 and 2 h after the glycerol injection. Compared with control animals, glycerol induced an increase in Na and K concentration in perilymph and endolymph, respectively, 1 and 2 h after the glycerol injection. No modification of the endocochlear potential was observed. These results are compatible with an increase in inner ear fluids osmolarity induced by glycerol.

Action Potentials↗

[Vestibular immune injury related to perilymph antigen specific antibody levels in the guinea pig].

This study demonstrates that degeneration of vestibular sensory cells depends on the integrity of immune responses in the endolymphatic sac (ES). Degeneration of the saccule occurred nearly twice as often as degeneration of the utricle and ampulla. Perilymph antibody levels were assessed following direct antigen (KLH) challenge to the endolymphatic sac in systemic presensitized guinea pigs. Mean perilymph antibody levels were significantly elevated in ears showing degeneration as compared to those which did not. Serum anti-KLH antibody levels were also significantly elevated in the ears with degeneration as compared to those without. Whether degeneration or recovery occurs, is largely dependent on the level of systemic immunization and perilymph antibody level within one week of antigen challenge to the ES.

Animals↗

[Effects of increasing perilymph calcium levels on various cochlear potentials].

In the present study, we examined the effects of increasing perilymph calcium (12.20 mmol/L) on guinea pig cochlear functions. The results demonstrated that high calcium perilymphs suppressed the magnitude of compound action potential of auditory nerves (CAP) with a prolongation of N1-peak delay at a constant intensity (90 dB SPL), but not of cochlear microphonics (CM). High calcium perilymph didn't change general endocholear potential (G-EP), while reduced the rapid change of EP at on and off set of 115dB SPL white noise exposure. Furthermore the value of negative potential (N-EP) induced by anoxia was decreased because of high calcium perfusions. Machanisms of these effects were discussed.

Action Potentials↗

[The different levels of prednisolone in perilymph after local and systemic treatment].

OBJECTIVE: The present study was to analysis the pharmacokinetics of prednisolone-21-hydrogensuccinate in the perilymph after local and systemic application. METHOD: On the local application, 5% prednisolone-21-hydrogensuccinate was directly applied into the round window niche under the microscopy. On the systemic application, the drug (60 mg/kg) was used intraperitoneal. Perilymphatic samples were obtained after variable periods of application. Levels of prednisolone-21-hydrogensuccinate in perilymph were measured by using HPLC. RESULT: The highest level of the drug was on (952.3 +/- 382.7) mg/L after 180 min. And remained on (18.72 +/- 16.97) mg/L after 960 min in the local application groups. In the systemic application group, the highest level of the drug was on(14.71 +/- 7.05) mg/L after 150 min. CONCLUSION: The results demonstrate that high levels and long time remain of prednisolone-21-hydrogensuccinate in perilymph are achievable by a single dose local application into the round window niche.

Administration, Topical↗

[IgA, IgM and IgG levels and antibodies to native DNA and collagen type II in the perilymph of patients with otosclerosis].

Investigation of IgA, IgM and IgG levels in the serum of 20 and perilymph of 10 otosclerosis patients discovered a significant rise in the IgG concentrations versus control values. Five otosclerosis patients demonstrated perilymph and serum antibodies to collagen type II. Perilymph of 5 and sera of 10 otosclerosis patients exhibited a high titer of antibodies to native DNA specific for autoimmune process. The findings evidence immune disturbances in otosclerosis proving participation of autoimmune mechanisms in the disease pathogenesis. The results may be helpful in design of the conservative treatments of otosclerosis hypoacusis.

Adult↗

Diagnosis and management of perilymph fistula: the University of North Carolina approach.

Perilymph fistula is a potentially disabling leakage of perilymphatic fluid from the otic capsule. The occurrence of perilymph fistula is now attributed to a wide variety of causes and the diagnosis is frustrated by a lack of characteristic signs or symptoms. A brief review of the literature and the University of North Carolina philosophy for the diagnosis and management of perilymph fistula is presented. Emphasis on timely evaluation and surgical technique is provided.

Fistula↗

[Idiopathic perilymph fistula].

This article presents 6 cases with idiopathic perilymph fistulae. The etiology of idiopathic perilymph fistula may be congenital malformation of the otic capule. Diagnosis of idiopathic perilymph fistula primarily depends on history and exploratory tympanotomy, but ENG-fistula test and positional audiometry are worth of diagnosing. During microsurgical procedure, attention must be paid to the presence of membrane of the round window niche. If a good repair of fistula is not followed by a good result, other lesions such as double labyrinth membrane rupture should be considered.

Adult↗

[Pharmacokinetics of amikacin in the perilymph and blood serum. An approach to the comparative evaluation of the potential ototoxicity of aminoglycoside antibiotics].

The pharmacokinetics of amikacin in serum and perilymph was studied on guinea pigs treated with its single subcutaneous administrations in doses of 100, 200, 400 and 800 mg/kg. Proportional relation between the values of the areas under the concentration against time curves of the antibiotic in serum and perilymph was shown. It suggested that the level of the antibiotic penetration into the internal ear might be predicted by the area under the concentration against time curve of the aminoglycoside. It was demonstrated that in equitherapeutic doses when D/Deq = 1 aminoglycosides had different areas under the concentration against time curve. Thus, the area under the curve of amikacin was 2.2 times higher than that of sisomicin. It was also demonstrated that the angle coefficient characterizing the relationship between the area under the concentration against time curve in perilymph and the dose standardized with respect to the equitherapeutic value was markedly higher for amikacin than for sisomicin.

Amikacin↗

[Perilymph fistulas--symptoms and indications for tympanoscopy].

In the last two years thirteen cases of perilymph fistula were treated by tympanoscopy and covering with connective tissue. Recovery of hearing was not observed in 4 totally deaf ears, but improvement was recorded in each of 9 cases with impaired hearing. Vertigo disappeared in 10 of 11 cases without any correlation with the degree of hearing loss. We perform tympanoscopy in suspected perilymph fistula, because prognosis is uncertain, spontaneous recovery with remaining defects may induce ménièriform syndrome, and pathway of infection should be closed. The diagnosis of a perilymph fistula must be solidified in cases of sudden deafness with vertigo, sudden hearing loss changing to the worse during medical treatment, sudden hearing loss without recovery during medical treatment, sudden hearing loss and subsequent onset of vertigo.

Adult↗

[Metronidazole pharmacokinetics in perilymph, aqueous humor and cerebrospinal fluid].

Since metronidazole is very effective against anaerobic bacteria, we studied its pharmacokinetics in perilymph, cerebrospinal fluid, aqueous humour, and serum. 1, 2, 4, 6, 10 and 16.5 hours after intraperitoneal injection of 200 mg/kg metronidazole to six groups of six guinea pigs each, we determined the drug concentrations by high-pressure liquid chromatography. In the serum, 1, 2 and 16.5 hours after application, drug levels of 194 +/- 22 mg/l, 127 +/- 54 mg/l and 2 +/- 1 mg/l respectively were found. Half-life was 6 hours. Similar high and long-lasting concentrations could be determined in the aqueous humour, cerebrospinal fluid and perilymph. In contrast to our findings with aminoglycoside antibiotics, beta lactam antibiotics and fosfomycin, we could not observe any retention of metronidazole in the perilymph.

Animals↗

Probenecid reduces cochlear effects and perilymph penetration of furosemide in chinchilla.

Previous investigation has suggested that the ototoxicity of furosemide is related to penetration of the drug into the inner ear and that active drug transport out of the inner ear may be responsible for maintaining the serum-perilymph drug concentration gradient. We further tested this hypothesis by investigating the endocochlear potential (ototoxicity) and furosemide perilymph concentrations after furosemide administration to chinchillas pretreated with the organic anion transport inhibitor, probenecid. Probenecid pretreatment attenuated the fall in endocochlear potential seen after furosemide (25 mg/kg i.v.): untreated, 58.6 +/- 27.0 mV; probenecid pretreatment, 14.1 +/- 11.9 mV (P less than .01). Furosemide concentrations in perilymph were correspondingly lower after probenecid (P less than .003), although serum furosemide concentrations were not affected by probenecid pretreatment. Diuresis, measured over an 8-hr period after furosemide, was also uneffected by probenecid. These results confirm the proposed relationship between inner ear furosemide concentrations and the occurrence of ototoxicity due to this drug. However, the determinants of penetration of this drug into the inner ear are unclear. The observation that probenecid pretreatment attenuates the ototoxic effect of furosemide while the diuretic effect is preserved suggests this drug combination warrants further investigation.

Animals↗

Perilymph total protein levels associated with cerebellopontine angle lesions.

The total protein levels in the perilymph of patients with acoustic neuromas, meningiomas, and Meniere's disease are contrasted. All specimens were obtained from the lateral semicircular canal during removal of the bony labyrinth. Any specimens with significant contamination by hemoglobin or serum proteins, as judged by the presence of hemoglobin/haptoglobin complexes, were discarded from this study. The findings of greatly increased perilymph protein levels in the tumor groups confirmed the reports of other workers. The levels in the Meniere's disease group compared favorably with the normal protein levels in perilymph. A very significant (p Less Than 0.05) difference between the acoustic neuroma group and the meningioma group is noted. This difference is probably tumor related, because in all cases of both groups, tumor entered and filled the internal auditory meatus.

Cerebellopontine Angle↗

[Effects of lowering perilymph calcium concentration on various cochlear potentials].

In the present experiment, changes in compound action potentials of auditory nerve (CAP), cochlear microphonics (CM) and endocochlear potentials were observed when the calcium concentration of perilymph was reduced by means of perilymph perfusion, with the aim of analyzing how calcium was involved. Perfusion with Ca(2+)-free artificial perilymph reversibly suppressed both CAP and CM amplitudes, but did not alter the basic nonlinear properties of CAP I/O curve. Furthermore, the perfusion did not alter the EP and negative EP (n-EP) induced by anoxia but eliminated the fast change of EP with respect to turning on and off of intense sound. The mechanisms underlying the effects of calcium are discussed.

Action Potentials↗

The penetration of gentamicin and neomycin into perilymph across the round window membrane.

Many commonly employed otic drops contain aminoglycoside antibiotics that may be toxic to the inner ear. A variety of chemicals such as ionic solutions, certain anesthetics, and epinephrine have been shown to diffuse across the round window membrane into the perilymph. Twelve adult cats were studied in this experiment. The auditory bulla was exposed and solutions containing gentamicin or neomycin concentrations similar to that commonly used in otic drops were applied to the round window niche for 15 minutes and washed with saline solution. The gentamicin and neomycin concentrations in the round window niche wash and the perilymph were then assayed by a radioenzymatic method. Concentrations of both antibiotics were observed in the perilymph. Thus, the round window membrane is a route through which these ototoxins may gain access to the inner ear.

Animals↗

The effect of the cationic composition in perilymph upon the N1 latency of the guinea pig.

Although a suitable cationic composition in perilymph is known to be essential for the generation of N1, the effect of the cationic change upon the N1 latency has never been investigated in detail. The scala tympani was perfused with an artificial perilymph with a high K+, low Na+ or low Ca2+ content, with simultaneous measurement by an ion-selective microelectrode to observe its effect upon the N1 latency. An excess of K+, a depletion of Na+ and a depletion of Ca2+ in perilymph individually suppressed the N1 amplitude and elevated the N1 threshold. The N1 latency was not prolonged in the high K+ group but the significant prolongation was observed in the other two groups.

Animals↗

Noise-induced perilymph fistula.

Perilymph fistulae are difficult to diagnose because they present with a wide variety of signs and symptoms, they are associated with many etiologies, and they often mimic other conditions. In this article, we describe a case of perilymph fistula that featured one of its more rare causes: acoustic trauma--specifically, damage from a loud blast from the siren of a fire engine. We also review the literature and discuss the difficulties of diagnosis and treatment and the possible mechanisms by which acoustic trauma and other etiologies cause perilymph fistulae.

Adult↗