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At least 1,099 records · Page 61Linked to original sources
PubMed1984

Cytochemical localization of adenylcyclase in the lateral wall of the inner ear.

The cytochemical localization of adenylcyclase in the lateral cochlear wall was studied using a modification of the Reik -Howell method. All the cell membranes of the stria vascularis and spiral prominence cells, except the vascular endothelium, showed a low enzyme activity. In the marginal cell and spiral prominence epithelium facing the endolymph, this activity was limited to the perilymphatic membrane sections. The results are discussed.

Adenylyl Cyclases↗
PubMed1975

[Inner-ear of monkeys under the influence of streptomycin-sulfate (author's transl)].

Eight monkeys were treated with 65 X 150 mg/kg Streptomycine-Sulfate per day given intramuscularly. Their vestibular reactions were investigated several times during and after (up to 7 1/2 months) the medication. Using nystagmography, a decrease of excitability could be realized as long as the drug was given. After the stop of the injections the excitability returned, mostly even up to the normal level. The most reliable vestibular reactions were the vestibular threshold, respectively duration and frequency of the postrotatory nystagmus. Additional medicaiton of Ozothin had some influence on the toxicity of Streptomycine towards the auditory system, but no effect at all regarding the vestibular reactions.

Animals↗
PubMed1981

The energy dispersive X-ray microanalysis technique in the study of fluids and tissues of the brain and the inner ear.

The temporal bone from the fetal and adult mouse and brain from fetal and adult rat were cryosectioned in a conventional cryostat and -30 degrees C using 16 micrometers thick sections. The elemental composition was analyzed in the fluid-filled spaces of the membranous labyrinth and ventricular cavities of the brain. After drying these spaces containing small crystal-like aggregations of material which morphologically differed depending on their elemental composition. This changed during embryonic maturation. The qualitative X-ray analytical microscopy seems to be a reliable method to follow changes in the elemental composition of fluids.

Aging↗
PubMed1995

Hair cell replacement in the avian inner ear following two exposures to intense sound.

The present study is concerned with the degree to which the avian cochlea retains the capacity to regenerate hair cells following repeated exposures to intense sound. Two groups of chicks were exposed once to an intense pure tone for 48 h at either 2 or 16 days of age. In a third group, they were exposed to the same stimulus at both ages. Structural alterations of the auditory epithelium were assessed both qualitatively and quantitatively at 0, 12 or 26 days following the single exposure at 2 days of age, and at 0 or 12 days following the single or second exposure at 16 days of age. The numbers of hair cells lost in the twice-exposed birds and those exposed once at 2 days of age were approximately 24 and 36%, respectively, and were not significantly different. Interestingly, the single exposure at 16 days of age caused greater hair cell loss (61%). Twelve days after overstimulation, the hair cell population in all experimental groups returned to near normal levels due to the emergence of new hair cells. This observation of hair cell replacement extends the early findings that birds are able to repair their acoustically damaged ears after either a single or repeated overexposure.

Animals↗
PubMed2002

[Papillary tumor of the inner ear: adenoma or carcinoma?].

A 46-year-old female patient presented relapsed left-sided hearing loss and progressive left facial nerve palsy. At first, the computed tomography (CT) scan and magnetic resonance (MR) imaging did not indicate a diagnosis of a tumorous lesion. Nine years after the first symptoms, a destructive cystic neoplasm of the pars petrosa of the temporal bone was then evident. The lesion was surgically removed by radical resection. Histologically, a papillary tumor of the endolymphatic sac was diagnosed. These tumors tend to become destructive and more or less aggressive, but they do not metastasize. Therefore, the best term for them should be "aggressive papillary tumors of the endolymphatic sac" to avoid classification as an adenoma or adenocarcinoma.

Adenocarcinoma, Papillary↗
PubMed1999

[Bone neogenesis in a rare space-occupying lesion of the inner ear canal].

Hemangiomas of the skull base are rare neoplasms and are easily misdiagnosed as acoustic neuromas when occurring in the internal auditory canal. Among these tumors, ossifying hemangiomas are characterized histologically be newly formed bone tissue within their substance. We describe a 26-year old female patient who presented with left-sided sensorineural hearing loss and tinnitus. T2-weighted magnetic resonance imaging demonstrated a bright space-occupying lesion of the internal auditory canal with extension to the geniculate ganglion. Bony erosions of the internal auditory canal were proved by high-resolution computed tomography. A hemangioma was suspected preoperatively and was resected via a middle cranial fossa approach. Histologically, new bone formations were found in a cavernous hemangioma. In general, radiologic findings can suggest a hemangioma of the internal auditory canal and help to differentiate it from acoustic neuroma. Based on the histological findings of intratumoral bone formation, the hemangioma in our patient was classified as an ossifying hemangioma. However, reactive bone formation at the borders of a tumor in the internal auditory canal can also be mistaken as new intratumoral bone formation.

Adult↗
PubMed1999

Beta1-adrenergic receptors but not beta2-adrenergic or vasopressin receptors regulate K+ secretion in vestibular dark cells of the inner ear.

Receptors were identified pharmacologically in functional studies where K+ secretion was monitored as transepithelial current (Isc). Further, receptors were identified as transcripts by cloning and sequencing of reverse-transcriptase polymerase chain reaction (RT-PCR) products. Isc under control conditions was 796 +/- 15 microA/cm2 (n = 329) in gerbilline VDC and 900 +/- 75 microA/cm2 (n = 6) in murine VDC. Forskolin (10(-5) m) but not 1, 9-dideoxy-forskolin increased Isc by a factor of 1.42 +/- 0.05 (n = 7). 10(-9) m Arg8-vasopressin and 10(-9) m desmopressin had no significant effect in gerbilline and murine VDC. Isoproterenol, norepinephrine, epinephrine and prenalterol stimulated Isc maximally by a factor of 1.38 +/- 0.04 (n = 7), 1.59 +/- 0.06 (n = 6), 1.64 +/- 0.03 (n = 8) and 1.37 +/- 0.03 (n = 6), respectively. The EC50 values were (1.4 +/- 0.7) x 10(-8) m (n = 36), (2.5 +/- 1.0) x 10(-8) m (n = 31), (1.7 +/- 0.7) x 10(-7) m (n = 36) and (5 +/- 4) x 10(-7) m (n = 32), respectively. Propanolol inhibited isoproterenol-induced stimulation of Isc. Atenolol, ICI118551 and CGP20712A inhibited isoproterenol-induced stimulation of Isc with a pKDB of 5.0 x 10(-8) m (pKDB = 7.30 +/- 0.07, n = 38), 4.4 x 10(-8) m (pKDB = 7.36 +/- 0.14, n = 37) and 6.8 x 10(-12) m (pKDB = 11.17 +/- 0.12, n = 37), respectively. RT-PCR of total RNA isolated from microdissected vestibular labyrinth tissue using specific primers revealed products of the predicted sizes for beta1- and beta2-adrenergic receptors but not for beta3-adrenergic receptors. Sequence analysis of the amplified cDNA fragments from gerbilline tissues revealed a 96.4%, 91.5% and 89.6% identity compared to rat beta1-, beta2- and beta3-adrenergic receptors, respectively. These results demonstrate that K+ secretion in VDC is under the control of beta1- but not beta2- or beta3-adrenergic receptors or vasopressin-receptors.

Adrenergic beta-1 Receptor Agonists↗