Biomedical subjects

R Aibara

Publications and source records attributed to R Aibara.

11 recordsLinked to original sources

PubMed2001

Human middle-ear sound transfer function and cochlear input impedance.

The middle-ear pressure gain, defined as the ear canal sound pressure to cochlear vestibule pressure gain, GME, and the ear canal sound pressure to stapes footplate velocity transfer function, SVTF, simultaneously measured in 12 fresh human temporal bones for the 0.05 to 10 kHz frequency range are reported. The mean GME magnitude reached 23.5 dB at 1.2 kHz with a slope of approximately 6 dB/octave from 0.1 to 1.2 kHz and -6 dB/octave above 1.2 kHz. From 0.1 to 0.5 kHz, the mean GME phase angle was 51 degrees, rolling off at -78 degrees /octave above this frequency. The mean SVTF magnitude reached a maximum of 0.33 mm s(-1)/Pa at 1.0 kHz with nearly the same shape in magnitude and phase angle as the mean GME. The ratio of GME and SVTF provide the first direct measurements of Z(c) in human ears. The mean Z(c) was virtually flat with a value of 21.1 acoustic GOmega MKS between 0.1 and 5.0 kHz. Above 5 kHz, the mean Z(c) increased to a maximum value of 49.9 GOmega at 6.7 kHz. The mean Z(c) angle was near 0 degrees from 0.5 to 5.0 kHz, decreasing below 0.5 kHz and above 5 kHz with peaks and valleys.

Acoustic Impedance Tests↗

PubMed1998

Histochemical study of the canine inferior pharyngeal constrictor muscle: implications for its function.

The inferior pharyngeal constrictor muscle (IPC), which consists of the thyropharyngeal (TP) and cricopharyngeal (CP) muscles. plays an important role during deglutition. The histochemical properties of the canine IPC muscle were investigated. The motor endplates of the TP muscle clustered at the midlength of the muscle, while those of the CP muscle were scattered diffusely. The glycogen depletion technique suggested that most of the CP muscle fibers terminated into the belly of the muscle and fiber lengths varied. With ATPase stain, type II fibers were shown to be predominant in the TP muscle, while type I fibers were predominant in the CP muscle. The diameter of the TP muscle fibers was significantly larger than that of the CP muscle. Although the histochemical characteristics of these two muscles were markedly different, they gradually changed, resulting in their coordinated physiological movements.

Adenosine Triphosphatases↗

PubMed1998

Motor innervation of the guinea pig interarytenoid muscle: reinnervation process following unilateral denervation.

The authors investigated the process of denervation and reinnervation of the interarytenoid (IA) muscle in the guinea pig using transmission electron microscopy and glycogen depletion technique after unilateral transection of the recurrent laryngeal nerve (RLN) and superior laryngeal nerve to clarify the innervation pattern of the unpaired IA muscle. Anastomosis between the bilateral arytenoid branches was confirmed in the belly of the IA muscle. Five weeks after transection, all of the IA muscle fibers appeared to have been reinnervated by the contralateral RLN. As the arytenoid branch of the RLN runs together with that of the contralateral RLN in a single intramuscular nerve funiculus, it is possible that collateral sprouting branches grow and extend into the adjacent denervated Schwann's sheaths. The authors conclude that the unpaired IA muscle, as a whole, receives specific motor nerve supply from the bilateral RLNs, although each muscle fiber is innervated unilaterally.

Animals↗

PubMed1997

[Relationship of Onodi cell to optic neuritis--radiological anatomy on coronal CT scanning].

The relationship of paranasal sinusitis to optic neuritis remains controversial. One of the major sources of this controversy is that there are some reports of rhinogenic optic neuritis (RON) in patients with mild paranasal sinusitis or with almost normal paranasal sinuses. The Onodi cell is a posterior ethmoid cell which pneumatized far laterally and to some degree superiorly to the sphenoid sinus and is intimately associated with the optic nerve. Coronal CT scanning is requisite to detect the Onodi cell; when it is present, an image of the sphenoid sinus just as if it were divided into top and bottom is characteristic. In our material from 200 patients (direct coronal CT scans 10 mm in width), the Onodi cell was observed in 7%. A case of RON whose pathogenesis was considered to be a direct spread of inflammation from the localized infection of the Onodi cell is reported. Ethmoiditis localized to the Onodi cell seems to play an important role in the pathogenesis of RON. Continued careful documentation of the localized posterior paranasal sinus lesion around the optic canal by detailed diagnostic imaging and endoscopic sinus surgery is necessary to resolve the disease entity of RON.

Adult↗

PubMed1997

[Diagnostic value of magnetic resonance imaging in postoperative maxillary cyst].

Magnetic resonance imaging (MRI) is superior to conventional X-ray tomography and CT scanning in detecting postoperative maxillary cysts (POMCs). We analyzed the MRI features of 51 cases (72 sides) and compared them with the operative findings of 42 cases (52 sides) of POMC. The total number of cysts diagnosed was 121. Multiple cysts were found in 37 sides (51%) and bilateral cysts were found in 21 cases (45%). According to classification of POMC based on location in the maxilla the central cysts were found in only 38% of all cysts (peripheral ones in 62%). In the 42 patients operated on, 69 of 83 cysts which had been detected by MRI were confirmed, whereas there were two additional cysts which could not be diagnosed preoperatively. Sixty four of 71 cysts were opened to the nasal cavity under endonasal endoscopic control. The other seven cysts (five sides) were operated on via a buccogingival incision. Detailed and accurate diagnosis by MRI and development of endoscopic instruments enabled endonasal surgery in most (91%) sides of the POMC. In five cysts of the superior type which are small isolated and distant from the lateral wall of the nasal cavity, endoscopic endonasal surgery was not indicated. In conclusion, MRI for POMC was extremely helpful in selecting a surgical approach.

Cysts↗

PubMed1996

Neuromuscular junctions of the posterior cricoarytenoid muscle in the adult rat: a scanning electron microscopical study.

Neuromuscular junctions in the posterior cricoarytenoid (PCA) muscle of the adult rat larynx were examined by scanning electron microscopy. Two types of focal junctions were characterized by the nerve endings with terminal varicosities or terminal buttons and by the subneural apparatuses with a group of cup-like depressions (2-5 microns in diameter), not labyrinthine gutters. One type of the subneural apparatuses consisted of a large number (more than 20) of depressions with predominantly slit-like junctional folds. The other type was characterized by a small number (about 10) of depressions with a few junctional folds. From the relative proportions of the two types of muscle fibers and subneural apparatuses in the rat PCA muscle, we suggest that the Type II fibers have the apparatus consisting of numerous small depressions with many junctional folds, while that of the Type I fibers consists of a small number of depressions with a smaller number of junctional folds. It is suggested that the structural differences of the subneural apparatus reflect different types of muscle fibers.

Animals↗

PubMed1995

[Endoscopic endonasal surgery for postoperative maxillary cyst].

Endoscopic endonasal surgery was performed on 64 patients (69 sides) with postoperative maxillary cyst. We marsupialized the cyst in the inferior and/or middle meatus to enlarge it as much as possible. To facilitate an easier approach to the cyst wall in the inferior nasal meatus, some patients underwent submucous resection of the inferior nasal concha or inferior turbinectomy. Thirty-eight patients (44 sides) were followed for more than six months after surgery and a wide opening was confirmed in 36 (81.8%) of the 44 sides. Whether we should utilize an endonasal approach or a Caldwell-Luc approach depends mainly on the location of the medial wall of the cyst. We classified the cysts into medial, anterolateral and posterolateral types. Drawing a line between the anterior end of the inferior turbinate and the base of the lateral pterygoid process, on the axial plane of CT at the mid level of the inferior meatus, is the first stop. A medial cyst extends toward the midline across this imaginary line. A lateral cyst is subdivided into anterolateral and posterolateral based on the position of the center of cyst. The endoscopic endonasal approach resulted in excellent outcomes in medial and posterolateral cysts, while this approach was not found to be suitable for anterolateral cysts.

Adult↗

PubMed1991

[Motor innervation of the canine arytenoid muscle].

Dual motor innervation by the bilateral recurrent laryngeal nerves (RLNs) has been demonstrated in the human arytenoid muscle (AR). Whether AR of the dog receives dual motor innervation remains to be cleared yet, although the canine larynx is frequently used in experimental studies. To answer this question, the author observed the muscular structure in detail and anastomotic nerve branch between the bilateral RLNs, and then carried out glycogen depletion experiments on AR of dog compared with typical unpaired ARs of monkey and of guinea pig. 1) Muscular structure AR of the dog consisted of three parts of muscle bundles: the transverse arytenoid muscle (TVA), ventricular muscle (VT) and anonymous small bundle provisionally named the smaller interarytenoid muscle (IAm). While TVA and VT were paired type, IAm was unpaired type and lay horizontally on the dorsal aspect of the sesamoid cartilage around the midline. So the canine AR displayed a trigastric muscle as a whole. 2) Anastomotic nerve branch By the vital staining with methylene blue, the arytenoid branch of canine RLN ramified in three directions: anteriorly to the bellies of TVA and VT, medially to the anastomotic branch and superomedially to IAm. By the silver impregnation method of Barker and Ip, the bilateral IAm ramuli were found to form collateral anastomoses and terminate disorderly on the individual fibers. 3) Glycogen depletion experiments When an electrical stimulation was applied to the unilateral RLN in the monkey and the guinea pig, about one half of AR fibers were unstained with PAS staining and, in turn, these unstained fibers were known to be innervated by the ipsilateral RLN. While these unpaired ARs receive dual motor innervation as a whole muscle, every individual fiber is innervated by the unilateral RLN. In the canine VT and TVA, almost 90% of fibers were depleted of glycogen on the belly of the stimulated side, while the reverse was on the nonstimulated side. This finding suggests that most fibers of canine VT and TVA are ipsilaterally and the remaining fibers are contralaterally innervated. About one half of fibers of IAm were unstained and the others were stained. This pattern was similar to that observed in the monkey and the guinea pig. Therefore, IAm receives dual motor innervation from both RLNs as a whole muscle.

Animals↗

PubMed1990

[Multiple primary cancers of the head and neck].

Multiple primary cancers of the head and neck are not always rare. We have experienced 30 cases of multiple primary cancers in the Department of Otolaryngology, Ehime University School of Medicine from 1976 to 1989. The incidence ranged from 3.6% to 8.9% with flexible criteria. The minimum was 14 of 393 cases of all index cancers, strictly conformed with Warren's definition. The maximum was 29 of 327 cases of index cancers on the mucosal surfaces, including a combination of both head and neck cancers. In view of organic specificity of the index cancers, the incidence was high in the larynx and oral cavity, low in the nasopharynx and maxillary sinus. The concept of "multicentric cancerization" was verified by the result that 60% of the additional cancers were head and neck, esophagus and lung. During following-up studies of oropharyngeal, hypopharyngeal and laryngeal cancers, we have to examine the esophagus periodically due to high risk of occurrence of cancer. To compare the data of multiple primary cancers of the head and neck between institutions, adequate and detailed criteria should be established.

Aged↗

PubMed1990

[Application of laser surgery to the treatment of laryngeal cancer].

The authors utilized CO2 laser to treat laryngeal cancer in 28 patients. The operative methods were the following: Method I. Glottic T1 tumor was completely vaporized by laser irradiation alone. This method was employed in cases without involvement of the anterior commissure and cartilagenous portion. Method II. Radiotherapy was carried out after removal of major lesion by laser surgery. The purpose of this method was to improve the success rate of radiotherapy. Method III. After radiotherapy laser surgery was done to remove residual tumor as far as possible in patients who could not undergo radical surgery due to poor general condition. Method I, or complete tumor resection by laser surgery alone, seemed profitable because of short admission period. It is, however, indispensable to select patients suitable for this treatment. Method II permitted improving the success rate of radiotherapy. Even after vaporizing major lesion by laser irradiation, 60Gy irradiation was required. Method III, or laser surgery on postradiation residual tumor was often useful to treat the patients with poor general condition or who refused more radical surgery.

Carcinoma, Squamous Cell↗

PubMedDate not supplied

Effect of sinus surgery on visual disturbance caused by spheno-ethmoid mucoceles.

Fifteen patients suffering from visual disturbance of varying degrees caused by a mucocele of the posterior ethmoid and/or sphenoid sinuses underwent marsupialization of a mucocele into the nasal cavity. Five of the eight patients with severe visual loss worse than 20/200 showed recovery of measurable vision. Two of these five were operated on within 24 hours after the onset of visual loss and showed marked recovery to 20/25 and 20/15. The other seven patients who had relatively mild visual disturbance experienced improvement of visual acuity or remission of subjective complaints such as blurred vision post-operatively. During operation partial bony defect was found in the optic canal in 12 patients and in the skull base in 12 patients. A good understanding of this disease by ophthalmologists and otolaryngologists is essential for early diagnosis and prompt surgical treatment to avoid permanent visual dysfunction and operative sequelae.

Adult↗