Ginichiro Ichikawa

Studies on anaerobic bacteria in chronic otitis media

In the 760 cases of chronic otitis media studied from 1970 to 1976, the detection ratio of anaerobic bacteria and the relation between the nature of anaerobic bacteria and the conditions of focus were investigated. In 8.2% of 760 cases 9 kinds and 81 strains of anaerobic bacteria was detected. Most of the anaerobic bacteria were Peptococcus sp. or Bacteroides sp. and in general non‐sporogenic anaerobic bacteria accounted for 97.5%. Anaerobes were frequently detected in cases where the middle ear cavity was filled with cholesteatoma or granulation and in cases of infection recurring after operation.

Necrotizing Sialometaplasia in the Mouth Floor Secondary to Reconstructive Surgery for Tongue Carcinoma

Necrotizing sialometaplasia is a benign inflammatory process, which histologically can mimic squamous cell carcinoma. A 63‐year‐old man underwent left hemiglossectomy involving transplantation of a myocutaneous flap for squamous cell carcinoma of the tongue. One month after the operation, necrotizing sialometaplasia occurred in the minor salivary gland tissue of the mouth floor, compressed by the necrotic flap. This case is very unusual because of the ocurrence of necrotizing sialometaplasia in the floor of the mouth. The etiology of the lesion was considered to be ischemia secondary to compression by the necrotic myocutaneous flap. Acta Pathol Jpn 41: 689–693, 1991.

Outpatient chemotherapy for recurrent and/or advanced squamous cell carcinoma of the head and neck

AbstractBackground. The efficacy of the treatment of cancer has been traditionally judged by outcome measures such as disease-free survival, overall survival, and tumor response rate. Our goal of salvage and/or adjuvant chemotherapy is to improve not only the survival period but also the quality of life (QOL). The conventional regimens containing cisplatin (CDDP) require hospitalization of patients, which has been responsible for disappointingly low QOL. Thus, we developed a new outpatient regimen that has same magnitude of activity and less toxicity compared with conventional CDDP-containing regimens. Methods. Sixteen patients with recurrent or advanced head and neck cancer were treated by the outpatient setting Long-CF regimen. The Long-CF regimen consisted of cisplatin (CDDP) (CDDP, 5 mg/m2/2 h infusion on days 1–5, 8–12, 15–19, 22–26) and 5-fluorouracil (5-FU) [oral administration of tegaful-uracil (UFT-E), 400 mg/body on days 1–28]. Results. Among 16 patients entered in this trial, 1 patient was disqualified from analysis for reasons of protocol violation. Of 15 patients evaluable for response, 2 complete responses (13%) and 4 partial responses (27%) were achieved, with an overall response rate of 40%. Myelosuppression was the major side effect. Leukopenia and anemia (13% greater than WHO grade III) were dose-limiting toxicities. Other adverse reactions including mucositis were all mild and transient. Conclusion. As this regimen is given in an outpatient setting, we concluded that this regimen produced a beneficial effect in patients with recurrent and/or advanced head and neck cancer. Moreover, the toxicity of this regimen was limited; thus, attempts to increase the complete response rate by dose escalation or intensive scheduling appear warranted.

Cervical reflex induced by click stimuli in cats.

We studied click-evoked potentials in the anterior horn of the spinal cord in 17 cats. A concentric needle electrode was inserted into the anterior horn of the spinal cord at levels C3-C6. Potentials evoked with 105 dB SPL clicks were recorded with a peak latency of 4.89-5.10 ms only at the C3 level. These responses were observed 45-60 dB SPL above the auditory brainstem response (ABR) threshold, and no potentials were evoked by stimulation of the contralateral ear. Average was performed 100 times with changes in stimulation frequency of 1-20 Hz. The amplitude of the potentials decreased with increasing stimulus frequency, but there were no changes in ABRs. The responses disappeared after destruction of the medial vestibulospinal tract at the obex level, but ABRs were still recorded. The spinal nucleus of the accessory nerves was located in the anterior horn of the spinal cord at levels C1-C6, and the sternocleidomastoid muscle motoneurons were found at levels C1-C3. The click-evoked potentials recorded in this study reflect responses of the spinal nucleus of accessory nerves through the vestibulospinal tract to click stimulation. The responses have the same characteristics as vestibular-evoked myogenic potentials that can be recorded using surface electrodes over the sternocleidomastoid muscles of humans.

A clinical study on the magnetic stimulation of the facial nerve

Objectives: A clinical study on the usefulness of magnetic stimulation of the facial nerve, with special attention paid to the selection of the coil shape and stimulation procedures. Study Design: The subjects consisted of 55 patients with Bells palsy, 1 patient with a cerebellopontine angle (CPA) tumor, 1 patient with multiple sclerosis (MS), and 30 normal subjects. Three types of coils were used in this study; a 90‐mm large single coil, a 40‐mm small single coil, and a 20‐mm small double coil. Methods: The compound muscle action potentials (CMAPs) and long latency response were evoked by transcranial magnetic stimulation (TMS) with a 90‐mm large single coil. The 40‐mm small single coil was used to test blink reflex by aiming it at the supraorbital nerve as the target site. The subcutaneous activation of the infra‐auricular facial nerve was performed with the 20‐mm double coil. Results: The reproducible CMAP and long latency responses were obtained from normal subjects with TMS. However, responses were observed only in patients with relatively mild Bells palsy. The magnetic stimulation—evoked responses reflected the brainstem function in the patients with a CPA tumor and MS. Conclusion: Although magnetic stimulation remains inferior to conventional electric stimulation in some sense and requires further study, this method is potentially useful because it can stimulate the facial nerve continuously from the cortex to the periphery and can effectively evoke responses reflecting the brainstem function.

Equivalent dipoles for middle latency auditory evoked potentials using the dipole tracing method

During the last decade, new dipole localization techniques have prompted the search for the neuronal generators of evoked potentials. In this study we have reported the equivalent dipoles for the middle latency auditory evoked potentials (MAEPs) by the mean of these localization using the dipole tracing method. MAEPs that were recorded from 19 normal human subjects attending to random binaural clicks were analyzed using the dipole tracing method. Equivalent dipoles (EDs) were found, using both the single-dipole model and the two-dipole model, for components occurring from 0 to 60 ms after stimulus onset. The dipole analysis accounted for the real head geometry based on three-dimensional digitization of measured head shape, and the results were experimentally correlated to those of magnetic resonance imaging to increase the accuracy of ED localization. For components in the first 15 ms latency (P0 and Na), neither model provided EDs with reproducible high dipolality. Na was particularly difficult to analyze, as this component was often contaminated by myogenic potentials. The results provided by the two-dipole model for the Pa component (20-30 ms) showed three variations: in three subjects, one ED was located in each supratemporal cortex; in another three, one ED was located in the right temporal cortex and the other in the midbrain; and in the remaining thirteen subjects, both EDs were in the midbrain. The single-dipole model and the two-dipole model both found EDs in the midbrain for Nb. Further study is necessary to determine the cause or causes of the variety in our results. And it is also necessary to try the study using unilateral ear stimulation with/without contralateral masking noise for understanding the mechanism of the binaural interaction.

Induction Chemotherapy with Cisplatin, Etoposide, and Mitomycin-C (PEM) Regimen in Advanced Cases with Cancer of Pharynx and Oral Cavity

With the aim of improving survival rate in advanced head and neck cancer, we scheduled 26 patients to receive PEM regimen. This regimen consisted of cisplatin (CDDP)(P), etoposide (VP-16)(E), and mitomycin-C (MMC)(M) (CDDP 60 mg/ m2/2 hr infusion on day 1; VP-16 40 mg/m2/1 hr infusion on days 1-3; MMC 7 mg/m2 iv bolus on day 1). Of 25 patients evaluable for response, 8 complete response (CR), 14 partial response (PR) were achieved, with an overall response rate (RR) of 88%. Myelosuppression was major side effect and thrombocytopenia (23% greater than WHO grade) was dose limiting toxicity. Other adverse reactions including mucositis were all mild and transient. Since limited mucosal toxicity, full course of following treatment including radiotherapy and/or surgery could be done satisfactorily. We concluded that this regimen produced beneficial effect as the adjuvant setting in patients with cancer in pharynx and oral cavity because of limited mucosal toxicity.

Comparisons of auditory cortical imaging for the various dichotic listening

Abstract Aim : The study was designed to estimate the auditory laterality of the human brain that was based on the dichotic listening (DL) technique. Non-invasive detection to know the ear advantage is useful for the hearing aid fitting for mono-aural wearing. Subject : Ten normal hearing adult volunteers were employed in this study. Methods : 31ch-Auditory-evoked potentials (AEP) for the dichotic sounds were recorded electrically from the scalp. A 60dBSPL of vowel “/a/” was represented mono-aurally with a 50dBSPL of the contra-lateral masking noise, white noise, and multi-talker noise. Brain functions, especially for the cortical response, within the dichotic listening were visualized non-invasively using the scalp potential-based Laplacian mapping technique. Results : Right ear advantage for vowel sound within the left-brain dominancy can be observed in six subjects. The remaining four subjects could not be categorized in the term of ear advantage or brain laterality. Conclusion : It is observed that the auditory processing for the dichotic listening behavior differed from the mono-aural listening. Objective and non-invasive assessment for the brain laterality within the auditory dominancy can be applied for the hearing aids fitting technique.

Distribution and role of mast cells in human tonsil

Abstract Mast cells (MC) are an important component in inflammation and immune surveillance mechanisms, and play a key role in defense against bacterial infection. Since tonsils are involved in inflammatory and allergic reactions, and because mast cells are also part of these reactions, this study was to clarify the local distribution of human mast cells in tonsils. Tonsillar tissues were from patients suffering from chronic tonsillitis or hyperplastic tonsils, divided into atopy and non-atopy groups. The localization and distribution of mast cells was determined by immunohistological study using anti-tryptase and anti-C-kit antibodies. Furthermore, the expression of IgE was also investigated. We revealed that in both groups, mast cells were distributed in perivascular and interfollicular areas. However, the expression of tryptase and C-kit in interfollicular areas was more significant in non-atopy group rather than atopy group. In addition, IgE was significantly expressed in perivascular areas, crypt and subepithelial tissue of tonsils from atopy group. In contrast, there was no remarkable increase of IgE expression in interfollicular areas. The finding that mast cells are differently distributed in the tonsillar tissues incited us to investigate the possible new role of mast cells in the tonsillar tissues in inflammatory or allergic conditions.

A facial nerve study using transcranial magnetic paired stimulation.

OBJECTIVE The purpose of this study was to evaluate the refractory period of the facial nerve by transcranial magnetic paired stimulation (TMPS) with as short interstimulus interval (ISI) as possible. Also, by applying TMPS, the long latency response obtained at the same time was recorded and its neurophysiological characteristics were studied. METHODS (Experiment 1) The subjects comprised of 30 normal volunteers and 19 patients with Bells palsy. The experiments were carried out using two sets of Magstim model 200 and Bistim modules, a large coil measuring 90 mm in diameter with a maximal output of 2.0 tesla (T), and a Neuropack 8 (Nihon Kohden Co., Japan) to control the stimulation and record the electromyographic findings. The amplitude of compound muscle action potentials (CMAP) to the orbicularis oris muscle was studied by TMPS at the parieto-occipital region. The ISI was set at 0.9, 1.1, 1.3, 1.5, 1.7, 1.9 and 2.1 ms in order to measure the refractory periods of the nerve. (Experiment 2) The subjects comprised of ten normal volunteers. The same method as in experiment 1 was carried out. However, this time, the lead electrodes were placed on the orbicularis oculi muscle, similar to that of the blink reflex. The ISI was set at 40, 60, 80, 100, 200, 300, 500, 800 and 1000 ms, and the effects of the facilitation and inhibition were studied. RESULTS (Experiment 1) In normal subjects, when the ISI was less than 1 ms, a significant decrease in the amplitude was noted. In severe palsy cases with House-Brackmann Grade IV-V TMS yielded no response. In two of the cases of House-Brackmann Grade III, the CMAP was obtained. (Experiment 2) The long latency response with TMPS was most strongly inhibited when ISI was 80 ms. CONCLUSION We were able to investigate the refractory periods, the reflex pathway of the facial nerve and the trigeminal nerve including the pons and the medulla oblongata by TMPS.