Is facial nerve decompression surgery effective?
Explore the source record for details and available documents.
Decompression, Surgical↗
Biomedical subjects
T Takasaka
Publications and source records attributed to T Takasaka.
Steroid therapy for facial nerve palsy in children.
Explore the source record for details and available documents.
Adolescent↗
Voltage-dependent channels in dissociated outer hair cells of the guinea pig.
Voltage-dependent channels in outer hair cells (OHCs) dissociated from the guinea pig cochlea were investigated by the use of a whole-cell patch-clamp technique. Two types of K+ current were recorded from OHCs. One was a slowly inactivating K+ current that was activated at a potential more positive than -30 mV. Another is a K+ current that was already activated at resting membrane potential. After suppressing both K+ currents, depolarizing voltage steps elicited a slowly inactivating inward current that was dependent on external Ca2+ and was indicative of an L-type Ca2+ channel in OHCs. Aminoglycoside antibiotics known to be ototoxic selectively inhibited the Ca2+ current.
Aminoglycosides↗
Ion transport mechanisms in the outer hair cell of the mammalian cochlea.
Explore the source record for details and available documents.
Animals↗
Dysgenesis of melanocytes and cochlear dysfunction in mutant microphthalmia (mi) mice.
In order to evaluate the cytological homology of intermediate cells and melanocytes, and to investigate the function of melanocytes in the inner ear, hearing acuity and cochlear pathology were studied in three strains of mice, namely, wild type mice (+/+), albino mice without melanin (c2J/c2J), and microphthalmia mice with no melanocytes (mibw/mibw). Our histochemical data indicated that intermediate cells showed cytological characteristics almost identical to those of melanocytes and that disorders of melanin and/or melanocytes were reflected in the stria vascularis of each mouse. While c2J/c2J presented the same normal hearing acuity and normal structure of the stria vascularis as +/+, the hearing acuity of mibw/mibw mutants was severely impaired. Their stria vascularis was abnormally thin, lacking intermediate cells. According to these results, lack of melanin has little influence on hearing acuity; however, the absence of intermediate cells or melanocytes causes severe hearing loss, presumably due to a strial dysfunction.
Animals↗
Voltage-activated K channel in luminal membrane of marginal cells of stria vascularis dissected from guinea pig.
Inward rectifying K channel activity was observed in the luminal membrane of the marginal cell by use of the patch clamp technique. When pipette solution contained 150 mM KCl, the current reversed at 10.2 +/- 8.8 mV (N = 27). The channel current showed multiple subconductance levels and depolarization activated the channel very slowly (order of seconds). Current-voltage relationships in cell-attached mode showed inward rectification. The calculated slope conductance of inward and outward currents were 18 +/- 7 pS and 5.4 +/- 2.0 pS (N = 27), respectively. When pipette solution contained 75 mM NaCl and 75 mM KCl, the current reversed -7.0 +/- 7.6 mV (N = 6). When pipette solution contained NaCl or Na gluconate, the channel currents were outwardly directed within a range of -60 to 60 mV. These results suggested that the channel is selective to K+. The channel showed immediate run down after excision, and this rundown was not prevented by elimination of cytoplasmic Ca2+. The channel activity was not affected by an increase of intracellular cAMP and cGMP, an application of cytoplasmic catalytic subunit of PKA with ATP. Taking its density into consideration, the channel seems to contribute considerably to the K+ conductance of the luminal membrane of the marginal cell.
1-Methyl-3-isobutylxanthine↗
A characteristics protein highly expressed in guinea pig inner ear, defined by monoclonal antibody WH-1.
A new monoclonal antibody (termed WH-1; isotype IgG2b) was established using a homogenate of dissected guinea pig cochleas (N = 60) as immunogen. Western blotting and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) identified the WH-1 antigen as a protein or glycoprotein with M(r) approximately 40 kDa. Immunoperoxidase treatment of histologic cryosections of guinea pig cochlea, followed by light microscopic examination, revealed strong positive staining at three sites: (i) parts of Hensen's stripe, marginal band, covering net, and Kimura's membrane (within the tectorial membrane [TM]); (ii) Deiters' cells, pillar cells, Hensen's cells, and stereocilia of outer hair cells (within the organ of Corti); (iii) interdental cells, inner and outer sulcus cells, Reissner's membrane, and surface membrane of stria vascularis epithelium. Similar staining patterns were observed for cryosections of rat and mouse cochleas. Only a trace quantity of cross-reacting protein was detectable in brainstem. The protein was not detectable in tongue extract by Western blotting. However, sections of brainstem and tongue did show positive immunohistological staining with WH-1. Localization of WH-1 antigen was further examined by electron microscopy. WH-1 positivity on outer hair cell stereocilia, certain sites on the TM, interdental cell surface, Reissner's membrane epithelia, and inner and outer sulcus cells was confirmed. WH-1 antigen was not detected on inner hair cell stereocilia by light or electron microscopy. The localization of WH-1 antigen on outer hair cell stereocilia and TM suggests that it may play some role in adhesion between these structures.
Animals↗
Immunopathological features of palatine tonsil characteristic of IgA nephropathy: IgA1 localization in follicular dendritic cells.
IgA nephropathy (IgAN) is generally thought to be mediated by the glomerular deposition of circulating immune complexes containing IgA as the major antibody component. Upper respiratory infections and tonsillitis often precede IgAN, and in some cases tonsillectomy is effective for the treatment of IgAN. Thus, the tonsil seems to be a unique organ causing initial and/or progressive events to generate nephritogenic immune complexes in IgAN. In this study we focused on the analysis of immunopathological features of the palatine tonsil characteristic of IgAN patients by using an immunohistochemical technique. The IgA1 subclass was demonstrated in follicular dendritic cells (FDC) of the tonsil of IgAN patients, but not in FDC of non-IgAN controls. On the other hand, IgA2, IgG, IgM and C3 did not show any differences in distribution between the two groups. Moreover, the expression of decay-accelerating factor (DAF), an inhibitor of homologous complement activation, and transforming growth factor-beta 1 (TGF-beta 1), an inducer of antibody-producing cells to IgA class switching, in FDC and interdigitating dendritic cells of the tonsil, respectively, which was also clarified in this study for the first time, was found to be identically distributed in the two groups. These findings may support the idea that IgA1, possibly in an immune complex form, is trapped by FDC and plays an important role in the persistent activation of particular B cell repertoires responsible for the onset and/or progression of IgAN.
Adolescent↗
Isolation of acini from nasal glands of the guinea-pig.
A procedure for isolating the acinar cells of the serous gland in the mammalian nasal septum has been developed. This technique is characterized by meticulous and selective isolation with minimal contamination by the surface epithelial cells and employs enzymatic treatment with collagenase. The isolated cells were confirmed to be serous gland acini as shown by negative staining with Alcian blue and a high electron density of the granules. The acini were more than 90% viable as judged by trypan blue exclusion. Ultrastructural integrity of the cells was well maintained following the isolation procedure. Application of acetylcholine to the isolated acini induced an inward current in a whole-cell patch clamp and increased intracellular Ca2+ concentration measured by fura-2. These acetylcholine responses were completely blocked by atropine. These physiological findings directly demonstrated that nasal gland acini possess muscarinic-activated receptors as previously suggested. These isolated cells hold promise for the in vitro study of secretory mechanisms in the mammalian nasal gland.
Acetylcholine↗
Inhibitory effects of sho-seiryu-to on acetylcholine-induced responses in nasal gland acinar cells.
Sho-seiryu-to, a traditional Japanese herbal medicine, has been used extensively in the treatment of allergic rhinitis. The effects of Sho-seiryu-to on electrical responses induced by acetylcholine in dissociated nasal gland acinar cells were investigated using patch-clamp and microfluorimetric imaging techniques. The application of Sho-seiryu-to inhibited both K+ and Cl- currents augmented by acetylcholine. The elevation of intracellular Ca2+ and Na+ concentrations induced by acetylcholine was also inhibited by Sho-seriyu-to. These findings suggest that Sho-seiryu-to attenuated the secretion of water and electrolytes from the nasal glands through an anti-cholinergic effect.
Acetylcholine↗
Involvement of Na(+)-H+ exchange in intracellular pH recovery from acid load in the stria vascularis of the guinea-pig cochlea.
The effect of acid load by NH4+ prepulse method on intracellular pH (pHi) and Na concentration ([Na+]i) in the stria vascularis tissue was studied using fluorescence ratio image microscopy. The pHi and [Na+]i were determined with fluorescence indicator dyes, 2',7'-bis(2-carboxyethyl)-5,6-carboxyfluorescein and sodium-binding benzofuran isophthalate, respectively. Intracellular acidification from the basal pHi of 7.12 +/- 0.08 to 6.82 +/- 0.08 was induced by NH4+ prepulse. Subsequent addition to the standard NaCl solution gradually increased pHi to the control value. This Na(+)-induced pHi recovery was significantly inhibited by the presence of amiloride and absence of external Na+. Basal free [Na+]i was 19 +/- 5 mM in the stria vascularis. In the same maneuver of acid load, the pHi recovery was associated with the increase in [Na+]i sensitive to the amiloride derivative. Thus, the process of the pHi recovery from acid load was demonstrated to involve the Na(+)-H+ exchange in the stria vascularis.
Amiloride↗
Pathogenesis of attic retraction pocket and cholesteatoma as studied by computed tomography.
It is hypothesized that blockade of the tympanic isthmus causes isolation of the attic and the adjacent middle ear spaces and that subsequent building up of the negative pressure in these spaces results in retraction of the pars flaccida, leading to formation of attic retraction pockets and cholesteatomas. To examine this theory, computerized tomographic (CT) findings of these conditions were evaluated in a series of 53 ears with retractions of the pars flaccida (attic retractions of Tos type II or deeper), including both retraction pockets and cholesteatomas. In 26 of 28 ears with attic retraction pockets, at least a portion of attic was aerated, and in 22 of these 26 ears, the mastoid antrum was also aerated. In contrast, in the 25 cases with attic cholesteatomas, these numbers decreased to 10 and 5, respectively, and the lack of aeration of the attic was demonstrated in 15 of 25 (60%) of the cases. In three cases of cholesteatoma, follow-up CT revealed either growth of a cholesteatoma from a retraction pocket or development of a small cholesteatoma into a large one. In these ears it was seen that the well-pneumatized attic and mastoid antrum seen in the initial CT was depleted by the growth of cholesteatoma that took place over a period of 4 months to 2 years. These results, showing good patency of the aditus and a pneumatized antrum in early stages of most cases of retraction pockets and cholesteatomas, are not in agreement with the hypothesis that the blockade of the tympanic isthmus is responsible for the pathogenesis of retraction pockets and cholesteatomas originating in the pars flaccida.
Adolescent↗
Substance P decreases the non-selective cation channel conductance in dissociated outer hair cells of guinea pig cochlea.
Explore the source record for details and available documents.
Acetylcholine↗
Confocal laser microscopical images of calcium distribution and intracellular organelles in the outer hair cell isolated from the guinea pig cochlea.
We report the use of a confocal laser fluorescence microscope to observe the distribution of cytosolic Ca2+ and the localization of intracellular organelles and cytoskeleton in the isolated outer hair cell (OHC). Membrane-bound Ca2+ stained by chlortetracycline was mainly seen in the subcuticular region, the infranuclear region, and the region adjacent to the lateral wall. In contrast, the central portion of the cytoplasm and nucleus were devoid of detectable fluorescence of membrane-associated Ca2+, but were relatively rich in free Ca2+. The cuticular plate showed a lack of both membrane-bound and free Ca2+. Fluorescent clusters of mitochondria and endoplasmic reticulum were predominantly seen in the infracuticular and infranuclear regions, and some were associated with the lateral wall. These two types of cytosolic organelles which fluoresced upon chlortetracycline treatment are therefore presumed to sequester calcium. The characteristic distribution of the endoplasmic reticulum was observed in coincidence with the infracuticular network of F-actin. The subsurface cistern, which was shown to be analogous to the endoplasmic reticulum in terms of its biological function, is likely to be the source of Ca2+ for the actin-mediated process.
Actins↗
Hearing and glycoconjugates: localization of Le(y), Le(x) and sialosyl-Le(x) in guinea pig cochlea, particularly at the tectorial membrane and sensory epithelia of the organ of Corti.
Immunohistological examination of guinea pig cochleas was performed using a panel of 25 monoclonal antibodies directed to various lacto-, ganglio- and globo-series carbohydrate epitopes as well as mucin-type epitopes. Lacto-series structures were found to be localized at specific sites of the tectorial membrane (TM) and Corti's organ, i.e. alpha 1-->3 fucosyl type 2 chain (Le(x)) at Kimura's membrane, marginal band and covering net of TM; alpha 1-->2, alpha 1-->3 difucosyl type 2 chain (Le(y)) at covering net; and sialosyl-Le(x) and sialosyl-i at Kimura's membrane and sensory epithelia, particularly sensory tips of hair cells of Corti's organ. In striking contrast, ganglio-series structures (GM3, GD3, GD2, 9-O-Ac-GD3) were detected at spiral ganglion cells, neuronal fibres and stria vascularis, but were completely absent from Corti's organ and most of the TM. Other epitope structures defined by various antibodies were not detectable at any location. The functional roles of lacto-series carbohydrate epitopes expressed at TM and Corti's organ remain unknown. However, the expression of Le(y) (but not other structures) in association with developmental deficiency of TM induced by 6-N-propyl-2-thiouracil in rats suggests that Le(y) plays some role in normal TM development. The presence of Le(x) at Kimura's membrane and sialosyl-Le(x) at hair cell sensory tips of Corti's organ suggests the intriguing possibility that these fucosylated/sialosylated carbohydrate structures play some role in interactions (either attractive or repulsive) of these inner ear components, which have been implicated in the physiology of hearing, i.e. the conversion of sound waves to nerve impulses.
Animals↗
Cellular mechanism of acetylcholine-induced response in dissociated outer hair cells of guinea-pig cochlea.
1. The acetylcholine (ACh)-induced currents (IACh) in dissociated outer hair cells (OHCs) of guinea-pig cochlea were investigated using the whole-cell patch-clamp technique, in both conventional and nystatin perforated-patch configurations. 2. ACh and carbamylcholine (CCh) induced outward currents at a holding potential (VH) of -60 mV in the perforated-patch configuration. The IACh increased in a sigmoidal fashion over the concentration range between 3 x 10(-6) and 10(-3) M. The dissociation constant (KD) was 1.7 x 10(-5) M and the Hill coefficient (n) was 2.7. The KD and n for CCh were 8.7 x 10(-5) M and 2.2, respectively. Neither nicotine nor muscarine induced any detectable current up to a concentration of 10(-3) M. 3. Various muscarinic agonists such as oxotremorine-M, McN-A-343 and oxotremorine could also induce the outward currents, although these current amplitudes were about one-third that of ACh, indicating that they were partial agonists. 4. The muscarinic antagonists atropine, 4-DAMP, AF-DX 116 and pirenzepine inhibited the IACh in a concentration-dependent manner. The half-inhibitory concentrations (IC50) for atropine, 4-DAMP, AF-DX 116 and pirenzepine were 4.8 x 10(-6), 6.2 x 10(-6), 2.1 x 10(-5) and 2.9 x 10(-4) M, respectively. 5. When the extracellular Ca2+ concentration ([Ca2+])o) was reduced to lower than 1 mM, the amplitude of IACh, abruptly decreased. In a nominally Ca(2+)-free external solution ACh did not induce any current. The increase of [Ca2+]o beyond 1 mM did not change the IACh. 6. When OHCs were perfused intracellularly with a pipette solution containing 10 mM BAPTA in the conventional whole-cell mode, ACh could not induce outward K+ currents. The Ca2+ ionophore A23187 induced an outward current. These results indicate that intracellular Ca2+ is involved in the ACh response. 7. Calmodulin inhibitors such as chlorpromazine, W-7 and trifluoperazine inhibited the IACh in a concentration-dependent manner. 8. When OHCs were dialysed with either 100 microM GDP beta S or 1 micrograms/ml pertussis toxin (PTX) through the patch pipette at a VH of -60 mV, the IACh diminished within 10 min, whereas the IACh of the control remained steady for over 20 min, suggesting that a PTX-sensitive G-protein is involved in the ACh response.(ABSTRACT TRUNCATED AT 400 WORDS)
Acetylcholine↗
Nonselective cation and Cl channels in luminal membrane of the marginal cell.
Single-channel currents of the luminal membrane of marginal cells dissected from the guinea pig cochlea were investigated using the patch-clamp technique. Nonselective cation channels having a linear conductance of 27 pS were activated by depolarization, cytoplasmic Ca2+, and cytoplasmic acidification. Cytoplasmic ATP inactivated the channel. A mixture of 3-isobutyl-1-methylxanthine and forskolin activated a small-conductance Cl channel in the cell-attached mode. On excision in the inside-out mode, the Cl channel was inactivated, but it was reactivated by a cytoplasmic catalytic subunit of protein kinase A with ATP. This Cl channel had a linear conductance of 12 pS, and its activity was little affected by voltage. The sequence of permeation by anions was Br- > Cl > I-. The Cl channel blocker diphenylamine-2-carboxylic acid (3 mM) completely blocked the channel, but 5-nitro-2-(3-phenylpropylamino)-benzoic acid (50 microM) blocked it only partially. The above-mentioned characteristics are similar to those of the well-demonstrated Cl- channel, cystic fibrosis transmembrane regulator.
Adenosine Triphosphate↗
Catecholaminergic innervation in the vestibular labyrinth and vestibular nucleus of guinea pigs.
The vestibular sympathetic fibers of 20 guinea pigs were examined by immunohistochemical demonstration using tyrosine hydroxylase and dopamine B-hydroxylase. The vestibular sympathetics originated in the ipsilateral superior cervical ganglion and entered the internal auditory meatus along the labyrinthine artery. At the Schwann-glial border, some of the sympathetic fibers left the artery and went into the superior and inferior divisions of the vestibular nerve and made a loose meshwork among the Scarpa's ganglion cells, while other fibers kept following the labyrinthine artery. Both groups of fibers entered the cristae ampullaris and saccular and utricular maculas after several bifurcations in the cribrose areas and terminated either near the capillaries beneath the sensory epithelia, or among the vestibular nerve fibers. These fibers travelled freely in the vestibular labyrinth without being restricted to following blood vessels or vestibular nerve fibers. Some sympathetic fibers made direct contacts with the vestibular efferent fibers or the vestibular afferent fibers at the node of Ranvier. Sympathetic fibers were not observed in the sensory epithelia or semicircular canals, and were rarely found in the vicinity of the dark cells. The vestibular nucleus was also innervated by other catecholaminergic nerve fibers originating from the locus ceruleus, and the synaptic contacts were observed between the catecholaminergic nerve terminals and other neurons. These two peripheral and central catecholaminergic nervous systems were quite independent at the level of Schwann-glial border.
Animals↗