Masato Yagi

An Electrocochleographic Study of Acute Low-Tone Sensorineural Hearing Loss

SummaryTwenty-four patients with acute low-tone sensorineural hearing loss (ALHL) were examined using electrocochleography. The negative summating potential (SP) amplitude and the summating potential/action potential (AP) ratio were significantly greater in the ALHL patients than in normals. The SP/AP ratio was smaller in the ALHL patients than in patients with known Menieres disease and moderate hearing loss, although the SP amplitude was somewhat greater in the former. An abnormal increase in the SP amplitude following click stimuli was found in 54% of the ALHL patients, while the SP/AP ratio was increased abnormally in 63% of these patients. These findings suggest that the pathophysiology of ALHL may be similar to that for endolymphatic hydrops.

Sensorineural hearing loss associated with otitis media with effusion.

The clinical records of 1,372 cases of otitis media with effusion (OME) treated during the past 10 years were reviewed in search of associations with sensorineural hearing loss (SNHL). In 14 cases (1.0%), the development of SNHL was considered to be etiologically related to OME. These 14 cases were classified into two groups. In group A, which consisted of 5 cases, the clinical feature was acute onset of SNHL and gradual improvement. In group B of 9 cases, SNHL progressed gradually or insidiously and did not improve. Different pathophysiology may be assumed to underlie these two groups. The results of this study demonstrate that we have to pay attention to a possible development of SNHL during the course of OME.

Clinical characteristics of inferior vestibular neuritis

Abstract Conclusions: Inferior vestibular neuritis (IVN) is a relatively minor subtype of vestibular neuritis (VN) and its clinical characteristics are unique. Objectives: To clarify clinical characteristics of IVN in comparison with conventional VN. Methods: This was a retrospective case series review. Caloric responses and cervical vestibular evoked myogenic potential (cVEMP) responses were measured in 71 patients with VN. The patients were classified into three groups: (1) IVN group, who showed only asymmetrical cVEMP responses; (2) superior VN (SVN) group, who showed only asymmetrical caloric responses; (3) total VN (TVN) group, who showed asymmetrical responses in both tests. The clinical records of time course of subjective symptoms (duration of attack, duration of hospitalization, and time to remission) were reviewed and other profiles (age, sex, affected side, acute symptoms, and sequelae) were evaluated. Results: Of the 71 patients with VN, 13 (18%) were classified as having IVN. The mean age and time to remission of patients with IVN (44.2 ± 4.8 years, 0.9 ± 0.5 months) were significantly lower and shorter, respectively, than those of patients with TVN (57.3 ± 2.5 years, 4.9 ± 4.7 months). There were no significant differences in other symptoms and profiles among the three groups. No patients with IVN showed benign paroxysmal positional vertigo as a sequela.

Morphological Changes of Cochlea in a Strain of New-mutant Mice

The hearing ability and histological characteristics of the cochlea of a strain of new-mutant mice were analyzed. This new mutant arose as a spontaneous mutation in the C3H/He stock. The genetic mode is autosomal recessive and the animals show abnormal behavior such as circling, head-tossing and hyperactivity. The audiological findings exhibited no recordable auditory brain stem response (ABR) in any homozygotes at ages ranging from 11 days to 117 days. For morphological examination, we used 36 homozygote with ages ranging from 10 days to 18 months. The primary morphological abnormalities were observed in the organ of Corti. The stereocilia of the outer hair cells showed disarray throughout the whole cochlea, although outer hair cell cytoplasm became fully developed, including the nerve terminals. Age-dependent degeneration of the outer hair cells subsequently occurred from the basal to the apical part of the cochlea. The earliest change demonstrated in the outer hair cells was cuticular degeneration. Although the abnormalities of the inner hair cells occurred late, a complete loss of inner and outer hair cells was demonstrated. The stria vascularis was well preserved at a later age as were spiral ganglion cells. These histological findings confirm that this mouse is classified as a neuroepithelial-type mutant. As this animal was expected to have a single gene abnormality, molecular genetic studies on this animal can provide important information on the nature of histological changes of the hair cell from a mode of gene action.

Vestibular pathology in a new-mutant mouse

The histological characteristics of the vestibule in a strain of new-mutant mice were studied under light microscopy. These new-mutant mice, manifesting drawing back, circling, head-tossing and hyperactive behavior arose as a spontaneous mutation in the C3H/He stock. For our study, 36 of these mice ranging in age from 10 days to 18 months were used. At 10 to 15 days after birth, the vestibular gross anatomy was well-developed and all three cristae and two maculae were morphologically normal. Age-dependent degeneration of the saccular maculae was found to begin at 21 days, and almost all hair cells were missing at 90 days. Further, morphological changes in the utricular maculae appeared at one year, and a severe loss of hair cells was observed at 18 months. In contrast, the cristae ampullaris remained well preserved until the age of 18 months. The phenotype of the abnormal gene in these mutant mice correlates to the morphological abnormalities seen in the vestibule.

Primary Tuberculosis of the Nasopharynx with Erythema induratum of Bazin

A 44-year-old Japanese woman with primary tuberculosis of the nasopharynx associated with erythema induratum of Bazin (EI) is reported. The patient presented with erythematous nodules of the lower legs diagnosed as EI. Since EI is a tuberculosis-related skin disease, the presence of latent tuberculous lesions was investigated, and a tuberculous lesion was found in the nasopharynx. Primary tuberculosis of the nasopharynx is very rare. Furthermore, our review of the literature revealed no case in which nasopharyngeal tuberculosis acted as the latent focus of EI.

Differential diagnosis of proptosis: Report of 2 cases

We rarely encounter patients with proptosis, however, it is known that inflammation and extension of paranasal sinus tumors may cause this condition. We should consider the diseases that may cause proptosis to facilitate the diagnosis. Recently, we treated proptosis in 2 cases, one with inflammatory myofibroblastic tumor (IMT) and the other with malignant lymphoma. As these 2 diseases show various clinical features and these features frequently overlap, it is difficult to differentiate between IMT and malignant lymphoma without pathological examinations. In this study, we review the relevant literature reports and discuss the difficulties in establishing a clinicopathological diagnosis and present a slight distinction in magnetic resonance imaging.

A method for determining reference points in celloidin specimens for computer graphic reconstruction

SummaryFor three-dimensional computer graphic reconstruction of histological sections, it is important to determine reference points. We have developed a machine that makes reference points in a celloidin block for this purpose by drilling holes straight into the block. A sliding microtome is placed under the machine, which consists of a worktable, a stand, and a motor-driven unit. The celloidin block is sectioned on a microtome to determine a plane for serial sectioning. Several holes are then drilled in the block vertical to the plane selected. Serially sectioned specimens are next stained with hematoxylin and eosin and are mounted in the usual manner. Threedimensional reconstructions of the specimens were next done using a PC-9801 computer and CosmoZone-S software. As an example, the reconstruction of a guinea pig stapes is described.

Multiple fibroepithelial polyps arising from the inferior turbinate.

A 77-year-old man presented with long periods of left-sided nasal obstruction and intermittent epistaxis. Nasal fibroscopy revealed an unusual, white, cauliflower-like, well-circumscribed, firm polypoidal mass arising from the vertebral portion of the left inferior turbinate (Figure 1). The surface of the multilocular polyps was lustrous. Computed tomography showed soft-tissue opacity with no enhancement that filled the left vestibule without any bony destruction. The mass measuring 2 cm was removed by an endoscopic inferior turbinectomy. Pathological examination showed small exophytic polyps with constrictions. Figure 2 shows the fibroepithelial polyps (FEPs) consisting of a fibrous lesion covered by pseudostratified cylindrical epithelium, surrounding a hemangioma. Compared with normal nasal polyps, FEPs had less infiltration of eosinophils, lymphocytes, and inflammatory cells. There was no evidence of dysplasia or malignancy. The institutional review board of Tokyo Teishin Hospital approved this article.

Vestibular findings and brainstem pathology in two siblings with Cockayne's syndrome.

Two siblings with Cockaynes syndrome (CS) are described. Both showed cachectic dwarfism, photosensitivity and progressive neurological dysfunction. The damped-rotation test revealed no vestibular nystagmus in one of them, and reduced per-rotatory nystagmus in the other. Neuropathological examination in the former subject disclosed neuronal loss with fibrillary gliosis in the vestibular nuclei, whereas neuronal degeneration was not apparent in the abducens nuclei, the oculomotor nuclei and the paramedian pontine reticular formation. Our findings suggest that CS might cause vestibular dysfunction as well as hearing loss and that the lesions in the vestibular nuclei might be related to the vestibular dysfunction.