Kensuke Watanabe

Morphological changes in the inner ear induced by bacterial endotoxin

Escherichia coli-derived endotoxin was introduced into the middle ears of 10 guinea pigs 24 hr after intraperitoneal injection of the same endotoxin. The cochleae were removed 24 hr after the introduction of the endotoxin into the middle ears and observed by light and electron microscopy. Inflammatory cell infitration and bleeding were observed in both endolymphatic and perilymphatic spaces. Inflammatory cells also infiltrated the stria vascularis, spiral ligament, spiral prominence and the organ of Corti. Blood sludge was observed in almost all of the strial capillaries of the upper three turns, but in few of the basal turns. The hair cells were intact in every turn except for a small number of degenerated mitochondria. Intermediate cells of the stria vascularis were shrunken, and some of them showed degenerative changes. Marginal cells had also shrunken, but they were less shrunken than the intermediate cells. The shrinking of both cells caused the enlargement of the intercellular space of the stria vascularis.

Alteration in Capillary Permeability of Horseradish Peroxidase in the Stria vascularis and Movement of Leaked Horseradish Peroxidase after Administration of Furosemide

The permeability of horseradish peroxidase (HRP) from the capillaries of the stria vascularis and the movement of leaked HRP in this site were investigated over time after the administration of furosemide, a loop diuretic, for the purpose of clarifying the function of the stria vascularis. Guinea pigs were used as experimental animals. The stria vascularis became markedly edematous at 10 min after the administration of furosemide, while the vascular permeability of HRP was decreased. This edema was thought to result not from the high permeation of strial capillaries, but from the blockage of water transport into the ductus cochlearis by inhibition of the Na+/2Cl-/K+ cotransport system on the cell membrane of the marginal cells and the exudation from the intermediate cells due to change of cell membrane permeability. A large amount of the leaked HRP from the strial capillaries was taken into vacuoles of marginal cells 1 h after furosemide administration. In the present study, no leakage of HRP was observed in the ductus cochlearis. Destroyed or degenerated cells were observed in vacuoles of marginal cells 2 and 3 h after furosemide administration, suggesting that marginal cells have a phagocytic function. Two hours after furosemide administration, the vascular permeability of HRP and the function of intermediate cells was still at a decreased level, although the stria vascularis was almost restored to normal morphology. Three hours after furosemide treatment, the vascular permeability of HRP and the intake of HRP into intermediate cell vesicles were generally normalized, suggesting near restoration of stria vascularis function. In the non-furosemide-treated control group, no vacuolation was observed in marginal cells, nor was HRP intake observed in these cells.

Measurement of water loss in human nasal mucosa.

Background Regulation of the barrier function in the nasal epithelium seems to be affected by the pathogenesis of allergic rhinitis. The measurement of transepidermal water loss has proven to be an important noninvasive method for assessing the efficiency of the skin as a protective barrier. Although the nasal mucosal epithelium also has such a protective function, the precise mechanism still is unknown. Methods We studied the alteration of nasal mucosal water loss in the basal state and after the nontraumatic applications of physiological saline, hypertonic saline (10% NaCl), nasal barrier cream, and 10% glycerol on the mucosal surface of the inferior turbinate. Results We observed that nasal mucosal water loss was increased by hypertonic saline and decreased by nasal cream and glycerol. Conclusion For the first time, we showed the human nasal mucosal water loss both in the basal state and after topical application of various substances.

Hypertonic saline alters electrical barrier of the airway epithelium

OBJECTIVE: The effect of tonicity changes in nebulizer solutions and irrigations on nasal mucosa is not well known. The present study aims to determine the basic mechanism of hypertonic solution on airway epithelial barrier. STUDY DESIGN AND SETTING: We investigated the electrical potential difference (PD) that is influenced by both active transport and the transepithelial electrical resistance of the epithelial mucosa in the human nose in vivo. The short circuit current (SCC) revealed net ion transport across the epithelium in the guinea pig trachea in vitro. Finally, the size dependency of macromolecules across the tracheal mucosa was determined in vitro using FITC-labeled dextrans of different sizes. RESULTS: PD was significantly decreased after topical application of hypertonic solution both in human and in guinea pig nose. SCC was significantly decreased after application of hypertonic solution. The transport of these dextrans from the basolateral to the apical side was not increased significantly after apical application of hypertonic saline. CONCLUSIONS: Hypertonic saline enhances the electrical permeability of the airway epithelial mucosa but not transport of macromolecule in the short term.

Changes in Listing plane thickness caused by vestibular schwannoma: a parameter for evaluating the accuracy of the gravity-oriented internal model.

Objective Three-dimensional analysis of video-oculograms can be used to calculate Listing plane for patients and experimental subjects. Listing plane reflects the head’s orientation with respect to gravity, which suggests that the plane is derived from otolithic vestibular input, itself, or from a gravity-oriented internal model constructed through integration of visual, vestibular, and proprioceptive sensory inputs. The goal of this study was to determine whether the Listing plane can serve as a parameter for evaluating static (peripheral or central) vestibular function. Study Design Prospective study. Setting Tertiary referral center. Patients Healthy subjects and patients with unilateral vestibular schwannoma without any previous treatment. Intervention Diagnostic. Main Outcome Measures Video-oculograms were recorded from healthy subjects (aged 36.8 ± 6.3 yr) and from patients (aged 60.3 ± 7.5 yr) during voluntary gaze with the head in an upright or each-side-down orientation, and the thicknesses of the calculated Listing planes were then compared. Results Results revealed thickening of the Listing plane in patients only when the head was in an impaired-side-down orientation (1.250 ± 0.795 and 1.074 ± 0.759 degrees in the right- and left-side-down head orientations in healthy subjects versus 2.222 ± 1.237 degrees in the impaired-side-down orientation in patients), and this thickening correlated with caloric weakness. By contrast, neither the sensation of postural instability nor postural disturbance in force platform recordings contributed to the thickness of Listing plane. Conclusion The thickness of the Listing plane could be a novel parameter for quantitatively evaluating static vestibular (otolithic) function, although central compensation might exist.

Time course of the recovery of three-dimensional eye position in patients with acute cerebellitis.

Listings plane is a construction derived from eye position and reflects gravitational orientation. The cerebellum plays a key role in orienting and integrating sensory input concerning gravity from visual, vestibular and proprioceptive apparatuses. This suggests that the thickness of Listings plane could serve as a novel parameter for evaluating the accuracy of the constructed gravity-oriented internal model. We report a case with acute cerebellitis along with data on Listings plane, calculated from consecutive infrared video-oculogram recordings. We found thickening of Listings plane at the early stage of the disease, and a gradual reduction of the thickness into normal range in parallel with the recovery of the patients posture and gate. Notably, clinical improvement of the patients posture was delayed relative to the normalization of the thickness of Listings plane. The thickness of Listings plane reflects the stability of the cerebellar-mediated cognitive gravitational reference frame. This thickness value could serve as a parameter to quantitatively evaluate the function of the constructed internal model. Recovery from cerebellar ataxia (manifested as normalization of the thickness of Listings plane) was followed by recovery of muscular strength lost during the period the patient was by his disease forced to assume a lying position.

The relationship between eosinophils and ECP value in nasal secretion

Abstract Nasal mucus was sampled from nine patients of left nostrils with nasal allergy and lavaged fluid was taken from right nostrils. The mucuses were observed by electron microscope and ECP in lavage fluid was examined. ECP in lavage fluid and destruction index (granule vacuolation score×destruction score of eosinophil cell membrane) showed high correlation (R=0.988, p It was concluded that EOP in nasal mucus was released from lysed eosinophiles with destroyed cell membrane.

EOAE I/O curves in inner ear impairments

Abstract Input/output (I/O) curves of evoked otoacoustic emissions (EOAEs) reveal a saturation at 30 dB or thereabout above their detection threshold. It has been suggested that such I/O relation corresponds to that of the basilar membrane vibration related with an active electro-mechanical process of outer hair cells. EOAEs in response to 1–2 kHz short tone bursts were measured. EOAEs were examined in ears with idiopathic sudden hearing loss (HL), low tone type acute sensorineural HL, Menieres disease and noise-induced HL. Three types of shift that were downward, horizontal and combined were observed in their I/O curves. The downward shift was seen mainly in the ears with high tone HL and the horizontal shift was in the ears with low tone HL. Three types of shift were observed in the ears of Menieres disease, in which glycerol administration augmented EOAE amplitude beyond the normal saturation level of its cotralateral side. Measurements of EOAE I/O curves are useful for diagnosis of inner ear impairments related to outer hair cell dysfunction in ears with sensorineural HL.

Ultrastructural observation of adherence of eosinophils to their surroundings

This study concerned the way in which eosinophils adhere to their surroundings. Many fibrils were seen to adhere to the cell membrane of eosinophils migrating into the submucosa. Those eosinophils migrating into the epithelial layer adhered to the epithelial cells in 2 different ways: through the thin filaments bridging 2 cells and at the top of the cell projections. Eosinophils were found to move chemotactically through this eosinophil adhesion to the surrounding filaments or epithelial cells. It is possible that eosinophil granular protein directly affected the epithelial cells as a regulatory agent of the expression of adhesion molecules on individual epithelial cells, because eosinophil peroxidase was detected in the filaments bridging 2 cells. Accordingly, the expression sites of adhesion molecules must momentarily change under the direct cross-talk between 2 cells. Adherence between the eosinophils as well as large particles stretching between 2 eosinophils were also visualized.