Naruo Okada

Chewing ameliorates the effects of restraint stress on pERK-immunoreactive neurons in the rat insular cortex

We investigated the effects of chewing on the anterior and posterior insular cortices during restraint stress using phosphorylated extracellular signal-regulated kinase (pERK) levels as a marker of neuronal responses. The stress only group demonstrated increased numbers of pERK-immunoreactive cells in both the anterior and posterior insular cortices compared to the control group (p < 0.01). In the stress with chewing group, the stress-induced increase of pERK-immunoreactive cell numbers was suppressed in both insular cortices and these differences were statistically significant compared to the stress-only group (p < 0.01). The suppressive effects of chewing were more prominent in the anterior insular cortex than in the posterior insular cortex. In general, the anterior insular cortex contributes to emotional processing, whereas the posterior insular cortex is associated with sensorimotor processes. Therefore, these results suggest that chewing ameliorates the emotional and sensorimotor responses to stress in the anterior and posterior insular cortices, respectively, with a greater effect on emotion-forming processes than on sensorimotor processes.

Management of a Brain Abscess Presumably Caused by Radiation Osteomyelitis of the Mandible

In this clinical report, we present the management of a brain abscess that was presumed to be caused by radiation osteomyelitis of the mandible. The patient underwent chemoradiotherapy for oropharyngeal carcinoma on the left side at the Department of Otolaryngology of our hospital in 2000. Local recurrence or metastasis did not occur post-treatment. In January 2009, the patient was diagnosed with radiation osteomyelitis of the mandible on the left side, complicated by a pathologic fracture. In July 2011, numbness occurred in the left upper extremity and the patient was transferred to the emergency center of our hospital. A computed tomography scan showed a tumor lesion in the brain that was diagnosed as a brain abscess by magnetic resonance imaging. Neurosurgeons performed burr hole drainage of the abscess, followed by administration of antibiotics. Although impaired fine movements of the left hand remain, progress has been relatively favorable with no recurrence of osteomyelitis or brain abscess post-surgery.

Effect of articulatory rehabilitation after oral cancer surgery on higher brain activation

The present study aimed to verify the importance of postoperative articulatory rehabilitation in patients with oral cancer and to clarify the neurological changes underlying articulatory functional recovery. A longitudinal assessment of oral function and accompanying brain activity was performed using non-invasive functional magnetic resonance imaging (fMRI). We assessed 13 patients with cancers of the tongue and oral floor before and after ablative surgery. Articulatory function was assessed preoperatively and postoperatively using a conversation intelligibility test and the Assessment of Motor Speech for Dysarthria test. Patients also performed a verbal task during fMRI scans. The assessments were then repeated after the patients had undergone 4-6 months of articulatory rehabilitation therapy. Compared to pretreatment levels, articulatory rehabilitation resulted in a significant increase in activation in the supplementary motor cortex, thalamus, and cingulate cortex. The present study offers a quantitative assessment of the effects of speech rehabilitation by investigating changes in brain activation sites.

Effect of Local Anesthesia on Trigeminal Somatosensory-evoked Magnetic Fields

For objective neurophysiological evaluation of the function of the trigeminal system, magnetoencephalography- based TSEF (trigeminal somatosensory-evoked field) assessment would be valuable in providing spatial and temporal profiles of cortical responses. However, this necessitates knowledge of how TSEF varies with trigeminal nerve dysfunctions. We introduced a conduction block of the trigeminal nerve using local anesthesia (lidocaine) to temporally mimic nerve dysfunctions, and monitored TSEF changes. Following an electrical stimulation of the lower lip, a magnetic response with peak latency of approximately 20 ms was identified in all participants. Dipole for the peak was estimated on the post-central gyrus in the participant’s own magnetic resonance image. After normalization to Montreal Neurological Institute (MNI) space and inter-participant data integration, the summary equivalent current dipole localization among participants remained in the post-central gyrus, suggesting validity of the use of MNI space. Partial anesthesia of the lower lip led to a loss of the waveform characteristics of TSEF for electrical stimulation to the trigeminal nerve. We verified that the 20-ms latency cortical response of TSEF components localized at the primary sensory cortex can serve as a robust neurofunctional marker of experimental trigeminal nerve dysfunction.

Evaluation of postoperative changes in vascularized iliac bone grafts used for mandibular reconstruction

Vascularized iliac bone grafts are used for mandibular reconstruction, but the factors affecting graft maintenance are unknown. This study explored the postsurgical changes in vascularized iliac bone grafts in patients who had undergone mandibular reconstruction after segmental resection. The study involved 24 patients (16 men and eight women) with oral tumours or osteoradionecrosis. Thirteen patients required bare bone grafting (BBG) and 11 patients required reconstruction with soft tissue coverage (six with a skin paddle and five with direct closure). The bone graft maintenance rate (with regard to the height of the centre of the graft) was calculated immediately after surgery and at 3, 6, 12, 24, and 36months after surgery. The maintenance rate was significantly lower in the BBG group than in the soft tissue coverage group at 3, 6, 12, 24, and 36months, and in those who were fitted with dentures compared to those who were not at 6, 12, 24, and 36months. Local infection also influenced the maintenance rate, but not significantly so. These findings indicate that the reconstruction technique and denture use can affect the bone graft maintenance rate after mandibular reconstruction with vascularized iliac bone grafts.

Influence of a dosing-time on toxicities induced by docetaxel, cisplatin and 5-fluorouracil in patients with oral squamous cell carcinoma; a cross-over pilot study

ABSTRACT Docetaxel, cisplatin plus fluorouracil (DCF) regimen is a useful chemotherapy, but is sometimes withdrawn due to severe adverse effects (AE). In this study, we examined whether the chronotherapy of DCF regimen could reduce the drugs-induced toxicities in clinical practice. Patients with oral squamous cell carcinoma were enrolled. Chemotherapy started at 10:30 (Morning-dosing) or 18:30 (Evening-dosing) for 5 days by a cross-over design. AE were assessed for 14 days after an initiation of each dosing. The grades of nausea, vomiting and neutropenia were smaller during Evening-dosing than during Morning-dosing. These data suggest that the chrono-chemotherapy might provide a merit for reducing the DCF regimen-related severe AE.

Tooth contact and brain activity: an fMRI study

P3-r19 Changes in cerebral blood flow during singing: preliminary fNIRS study Mone Tsukimoto 1 , Yasunori Shiono 1, Tsuyoshi Matsumoto 1, Yasuhiro Kawano 1, Yasushi Fuchigami 1, Kunio Sato 2, Yoko Hoki 1 1 Dept. of Neurophysiol, Division of Neuroscience, Mie Univ Grad School of Medicine, Tsu, Japan 2 Dept. of System Engineering, Division of Environmental Science & Technology, Mie Univ Grad School of Bioresources, Tsu, Japan