Publications by authors named "Kenji Asamura"

Chondrosarcoma make up only 10-20% of malignant primary bone tumors, with 5-10% located in the head and neck (Downey TJ, Clark SK, Moore DW. Chondrosarcoma of the nasal septum. Otolaryngol Head Neck Surg 2001;125:98-100), and nasal septal chondrosarcoma is extremely rare.

View Article and Find Full Text PDF

Conclusion: This study clearly showed the molecular characteristics of head and neck squamous cell carcinoma (HNSCC) on the basis of gene expression patterns.

Objective: cDNA microarray has recently been shown to have the ability to represent the expression patterns of large numbers of genes from a small amount of tissue, potentially enabling definition of groups of patients with similar biological behavior of cancer. Although gene expression profiling using this technique has proven helpful for predicting the prognosis in various cancers, little is known regarding HNSCC.

View Article and Find Full Text PDF

To examine the frequency of the 961delT mitochondrial point mutation, considered to be associated with aminoglycoside-induced hearing loss, restriction fragment length polymorphism (RFLP) analysis was performed in (1) 334 unrelated sensorineural hearing loss (SNHL) patients and (2) 56 patients with aminoglycoside antibiotic injection history. Approximately 2% of the SNHL patients had the 961delT mutation, raising the possibility of a relatively high prevalence of this mutation among hearing impaired populations. However, the following findings cast doubt on whether this mutation is truly associated with hearing loss: (1) a similar frequency found in the control subjects, (2) hearing loss that was not segregated within the families, (3) rates of heteroplasmy and aging that were not correlated with the severity of hearing loss, and (4) a low prevalence among the aminoglycoside-induced hearing loss patients (1/56=1.

View Article and Find Full Text PDF

cDNA microarray analysis indicated that COL9A3 is one of the highly expressed genes in the cochlea. This suggests that collagen type IX has a crucial functional role in the inner ear and may be a candidate gene for hearing loss. Mutation analysis was carried out to find possible disease-causing mutations in this gene.

View Article and Find Full Text PDF

Objective: To develop gene expression profiles of young and old senescence-accelerated mouse (SAM) cochlea and identify genes responsible for aging-related hearing loss.

Methods: Gene micro-array slides containing 1101 mouse genes were hybridized to cDNA micro-arrays (Atlas Glass Array Mouse 1.0) that were synthesized using total RNAs from the cochlea of 2 mounts and 12 mounts mouse.

View Article and Find Full Text PDF

Type IX collagen is one of the important components, together with type II, V, and XI collagens, in the tectorial membrane of the organ of Corti. To confirm the significance of type IX collagen for normal hearing, we assessed the detailed morphological and electrophysiological features of type IX collagen knock-out mice, which have recently been reported as a deafness model. Through assessment by auditory brainstem response (ABR), knock-out mice were shown to have progressive hearing loss.

View Article and Find Full Text PDF

Objective: The final goal of this study is to develop a pre-operative fine needle aspiration biopsy (FNA) diagnostic system based on gene expression profiles. As the first step to that end, the present study was performed to determine whether the cDNA microarray system is applicable for histological evaluation of parotid gland tumors.

Methods: We investigated molecular characteristics on the basis of gene expression patterns of the two most common types of salivary gland tumors (pleomorphic adenomas and Warthin tumors) and normal salivary gland tissues, using the cDNA microarray system.

View Article and Find Full Text PDF

Objectives/hypothesis: The objective was to clarify the characteristics of deafness associated with the A1555G mutation within mitochondrial 12S ribosomal RNA gene in the absence of aminoglycoside exposure.

Study Design: Clinical and genetic studies in family members with the A1555G mitochondrial mutation were performed.

Methods: The subjects were 123 maternally related members of a large Japanese family with the A1555G mutation.

View Article and Find Full Text PDF

Recent progress in identifying genes responsible for hearing loss enables the ENT clinician to apply molecular diagnosis by genetic testing. This article focuses on three genes, which are prevalent and therefore commonly encountered in the clinic. GJB2 (connexin 26) is currently recognized as the most prevalent gene responsible for congenital hearing loss in many countries.

View Article and Find Full Text PDF