Hidehaku Kumagami

Changes of the action potential, the summating potential and cochlear microphonics in experimental endolymphatic hydrops.

The changes of the action potential (AP), the summating potential (SP) and cochlear microphonics (CM) were investigated in reference to the grade of endolymphatic hydrops produced by endolymphatic sac obliteration in guinea pigs. In a few cases with minimum endolymphatic hydrops, super-normal AP was obtained. With an increase of endolymphatic hydrops, CM responses were reduced although AP responses at intensive stimulation were maintained relatively well. It is thought that the polarity of positive SP, as observed in control, was influenced to deflect towards negative SP by an interaction between the increased degree of endolymphatic hydrops and the changes of the biochemical components of the inner ear fluids.

Interferon-lnduced Sudden Hearing Loss: Original Paper

With the increasing long-term use of interferon (IFN), several new adverse effects have been recognized. Very little attention, however, has been paid to auditory acuity. We encountered 3 cases of sudden hearing loss associated with IFN. We then co nducted a prospective study to assess the auditory function of 73 patients receiving IFN. Auditory disability (tinnitus and/or hearing loss) occurred in 32 patients (43.8%) during IFN therapy, among which audiometry documented sensorineural hearing loss in 27 cases (36.9%); 17 (48.6%) of the 35 patients receiving IFN-β had auditory disability, including hearing loss in 13 cases (37.1%), and 15 (39.5%) of 38 patients receiving IFN-α suffered from auditory disability. There was not much difference between the influences of IFN-α and -β. Auditory disability frequently developed in the later stages of treatment, and most patients recovered 7-14 days after the discontinuation of IFN. The results demonstrate that sudden hearing loss can occur as a side effect of trea...With the increasing long-term use of interferon (IFN), several new adverse effects have been recognized. Very little attention, however, has been paid to auditory acuity. We encountered 3 cases of sudden hearing loss associated with IFN. We then conducted a prospective study to assess the auditory function of 73 patients receiving IFN. Auditory disability (tinnitus and/or hearing loss) occurred in 32 patients (43.8%) during IFN therapy, among which audiometry documented sensorineural hearing loss in 27 cases (36.9%); 17 (48.6%) of the 35 patients receiving IFN-beta had auditory disability, including hearing loss in 13 cases (37.1%), and 15 (39.5%) of 38 patients receiving IFN-alpha suffered from auditory disability. There was not much difference between the influences of IFN-alpha and -beta. Auditory disability frequently developed in the later stages of treatment, and most patients recovered 7-14 days after the discontinuation of IFN. The results demonstrate that sudden hearing loss can occur as a side effect of treatment with IFN. This may reveal the association between autoimmunity and sudden hearing loss.

Experimental Labyrinthine Lesions through Stylomastoid Foramen

It was confirmed that the substances injected into the facial nerve through the stylomastoid foramen, reached every part of the inner ear. In sensitized animals, by repeated provocative injections of antigen, acute reversible episodes, very similar to that of Ménières disease, were observed. The injection of various solutions and the provocative injection into the sensitized animals, resulted in completely opposite reactions. In sensitized animals, the electrophysiological phenomena of the cochlea also showed fluctuations like Ménières disease.

Tinnitus due to Abnormal Contraction of Stapedial Muscle

The authors observed eight cases of intermittent tinnitus which appeared during the course of recovery from peripheral facial nerve paralysis of various etiology. The tinnitus occurred whenever a cert

Cancer of the head and neck in atomic bomb survivors: Hiroshima and Nagasaki, 1957-1976

A search was conducted in Hiroshima and Nagasaki for all cases of cancer of the lip, nose and nasal cavity, accessory sinuses, larynx, and the oral cavity and pharynx with their subdivisions occurring during the period 1957–1976 among a large, fixed cohort of atomic bomb survivors. A total of 232 cases were identified, of which 154 (66.4%) were histologically confirmed (definite cases). Among definite cases, cancer of the epiglottis and larynx predominated (31.2%), followed by accessory sinus (24.7%) and tongue (18.8%). Of the 154 definite cases, 141 (91.6%) were squamous‐cell carcinomas. Only two sarcomas were identified, neither of which was attributable to radiation exposure. Analysis of both total and definite cases, by both total group and major anatomic site, failed to reveal definite evidence of a radiation relationship. Although a suggestive relationship to radiation dose was found for accessory sinus cancers (P = 0.06) among the definite cases, inconsistencies in the data do not permit the conclusion that the incidence of tumors in this group increased as a result of atomic bomb radiation exposure. The medical literature concerning post‐irradiation head and neck tumors is briefly reviewed.

Chronological Changes of Electrocochleogram in Experimental Endolymphatic Hydrops

Chronological changes of the whole nerve action potential (AP), cochlear microphonics (CM) and summating potential (SP) in experimental endolymphatic hydrops in guinea pigs were studied during a period from 1 week to 13 months after the endolymphatic sac obliteration. Endolymphatic hydrops became extensive in month 3 and persisted thereafter. The threshold of AP increased with the lapse of time but good AP output potential was obtained, being maximum in month 3. The threshold of CM increased with the lapse of time. The CM output potential was the highest around week 3 when endolymphatic hydrops was slightly formed, and it decreased thereafter. SP responses at the frequencies of 8, 4, 1 and 0.5 kHz showed the reversed polarity of -SP in month 3 and changed towards potential 0 thereafter. In animals showing super-normal AP output potential, the cilia in the third row of outer hair cells were disarranged. This seems to be involved in recruitment.

Electrocochleographic study of sudden deafness.

By performing electrocochleography (AP, SP and CM) on 34 patients with sudden deafness, it was thought that the pathophysiology of this disease could be deduced. The various waveform patterns of AP and SP responses obtained in cases of sudden deafness were classified into the following types: 1) AP high response; 2) decreased AP high response; 3) AP low response; 4) dominant — SP; 5) — SP or + SP; and 6) AP, SP no response. The cases showing the type of dominant — SP and AP high response had satisfactory prognoses. In these cases the sensory epithelium and the cochlear nerve seemed to indicate a reversible condition being affected by the temporary functional block. Furthermore, it seemed to indicate that the neural regions related to the source of AP(N1) response were impaired in cases in which CM were recorded at normal response threshold in spite of the absence of AP(N1) response. In the unsatisfactory prognosis cases with decreased AP high response, AP low response and AP, SP no response in which only the extremely low or depressed CM responses could be recorded, it seemed that the sensory epithelium and the cochlear nerve were affected permanently, although the degree of impairment varied.

Detection of viral antigen in the endolymphatic sac

A study was devised to determine whether or not any immune defense mechanism is present when a virus invades the human endolymphatic sac (ES). The ES was removed from 14 fresh autopsy cases having no known premortem diseases in the middle and inner ears. Specimens were then examined for viral antigens including herpes simplex (HSV) type 1 and 2, mumps and cytomegalovirus using immunohistochemical methods. DNA examination by in situ hybridization was also performed for HSV HSV antigen and DNA were observed in 9 of the 14 cases studied. These findings suggest that the virus invades the ES but is impeded by an immune defense mechanism under normal conditions. Since disease may alter host defenses, further studies are warranted to study the relationship between HSV and patients with Menieres disease.

Vascular permeability to sodium fluorescein in the rabbit cranial nerve root: possible correlation with normal cranial nerve enhancement on gadolinium-enhanced magnetic resonance imaging

Vascular permeability in cranial nerve roots was examined after intravenous injection of sodium fluorescein in the adult rabbit. Fluorescence was observed in the distal nerves through the following portions: intracavernous portion of the oculomotor nerve, distal internal auditory camal segment of the facial nerve, and ganglionic portions of the trigeminal, glossopharyngeal and vagus nerves. In the acoustic nerve, the vestibular ganglion showed fluorescence. No fluorescence was observed in the olfactory or optic nerves. During in vivo gadolinium-enhanced magnetic resonance imaging (Gd-MRI) of two separate animals, trigeminal nerve enhancement was observed in the region showing fluorescence. Histologically, intense fluorescence was observed in ganglia and external nerve sheaths of the cranial nerves showing macroscopic fluorescence. A slight fluorescence was also seen in endoneurial connective tissue but not observed within the nerve fibers. The results of this study suggest that the physiological enhancement of human cranial nerves seen on Gd-MRI may correlate with vascular permeability.

Vascular permeability changes associated with experimentally induced facial nerve lesions in the rabbit

Changes in vascular permeability to sodium fluorescein following experimentally induced nerve lesions were examined in the rabbit facial nerve. Sodium fluorescein was injected intravenously as a permeability tracer and then localized by fluorescence microscopy. In control nerves, endoneurium showed only slight fluorescence while intense fluorescence was observed in the epineurium and perineurium. In nerves demonstrating edema and Wallerian degeneration, endoneurium was found to have an increased accumulation of tracer. This increased endoneurial vascular permeability in facial nerve lesions may explain nerve enhancement seen in gadolinium-enhanced magnetic resonance imaging in patients with facial nerve paralysis.