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Biomedical subjects

T Minatogawa

Publications and source records attributed to T Minatogawa.

At least 19 recordsLinked to original sources
PubMed2000

An effective synthesis of isoorientin: the regioselective synthesis of a 6-C-glucosylflavone.

Isoorientin, a 6-C-beta-D-glucopyranosyl-3',4',5,7-tetrahydroxyflavone, was synthesized in a 15% overall yield, in ten steps, starting from the commercially available phloroacetophenone. The C-glucosyl phloroacetophenone derivative, a synthetic intermediate that contains a free hydroxyl group that is para to the glucosyl moiety, was obtained by hydrogenolysis by taking advantage of differences in the hydrogenolysis rates between a benzyl protecting group and a 2-methylbenzyl protecting group. Aldol condensation of the C-glucosyl phloroacetophenone derivative with 3,4-bis-benzyloxybenzaldehyde afforded the corresponding chalcone as a precursor of the 6-C-glucosyl flavone. Construction of the flavone system by application of I2-DMSO, followed by deprotection, yielded isoorientin.

Flavonoids↗
PubMed1996

Allograft stapes surgery for conductive hearing loss in patients with ossicular chain anomalies.

An allograft stapes was used during surgical intervention for conductive hearing loss due to ossicular malformations in 11 ears of seven patients. The external auditory canal and tympanic membrane were normal in all ears. The surgical findings for the ossicles were stapes fixation (7 ears), stapes fixation with discontinuity of the incudostapedial joint (in both ears of one patient), a deformed incus and stapes crura compressed by the facial nerve (one ear in which the stapes was not fixed) and an anomaly of the incus and stapes combined with a dermoid cyst (in one ear in which the stapes was also not fixed). In all ears, the following procedures were performed: stapedectomy followed by sealing the oval window with a vein graft and placing an allograft stapes between the oval window and the lenticular process of the incus or the handle of the malleus. The allograft stapes was placed with its capitulum on the oval window in all cases, and fibrin glue was used for stabilizing the seal and the allograft stapes. The indications for stapedectomy for conductive hearing loss due to ossicular chain anomalies and the utility of allograft stapes are discussed.

Adolescent↗
PubMed1995

Effects of electrical stimulation of cervical sympathetic trunks on microcirculation in the facial nerve.

This study evaluates the circulatory effects of electrical stimulation of the cervical sympathetic trunks on blood flow in the common carotid artery and facial nerve tissue in dogs. Marked increases in arterial pressure and heart rate were observed due to electrical stimulation of the cervical sympathetic trunks, while blood flow volume in the common carotid artery and in the facial nerve tissue decreased markedly. It was assumed that microcirculation of the facial nerve is definitely impaired by electrical stimulation of the cervical sympathetic trunks, and the tonicity of the sympathetic nervous system appears to be a major factor in changes in the microcirculation of the facial nerve. It is well known that impaired circulation in the nutrient vessels of the facial nerve has an important effect on the pathogenesis of facial palsy. The hypertonicity of the sympathetic nervous system is closely involved in the onset of facial palsy.

Animals↗
PubMed1995

Evaluation of mastoid obliteration surgery.

The anatomic results of mastoid obliteration surgery on 54 ears during the past 10 years were analyzed, and the comparative utility of several materials for obliteration was evaluated. Thirty-three ears had primary chronic otitis media with or without cholesteatoma (group 1), and 21 ears had old open mastoid with intractable chronic discharge due to incomplete epithelialization (group 2). The materials used for obliteration were biologic (pedicled muscle flap, autogenous bone chips, tragal cartilage with perichondrium, allograft dura), nonbiologic (hydroxyapatite), or a combination of two of these materials. Evaluation at 2 months postoperatively showed that 42 ears were anatomically complete, whereas the other 12 ears were incomplete: three cases in group 1 and nine cases in group 2. The main causes of these unsatisfactory results were exposure of transplanted artificial material or partial loss of the pedicled muscle flap. In the long-term follow-up results, four ears were evaluated as unsatisfactory in group 1, and six ears in group 2, owing to shrinkage of obliterated tissue. The major causes of failure were anatomic incompleteness following surgery for old open mastoid cavity, in which the use of biologic materials for obliteration was much safer than nonbiologic material, and from the protrusion of artificial materials used.

Biocompatible Materials↗
PubMed1994

Developmental anomaly of the process of Folius.

We present four cases of an ossicular anomaly considered to consist of an abnormality of the anterior process and manubrium mallei (malleus handle). In one case, a thick bony bar was found extending from the neck of the malleus which fused with the posterior bony wall or the tympanic bone. No trace of the short process and umbo of the malleus was recognized. In two other cases, a similar bony bar was seen as well as a cartilaginous malleus handle that apparently was attached to the anterior part of the bony bar. On the basis of these findings, the bony bar was assumed to represent abnormally developed mesenchyme bone (os goniale), which later develops into the anterior process of the malleus. In the last case, no bony bar was seen, but a V-shaped ossicle was recognized, one end of which was connected to the malleus head by fibrous tissue. Since this abnormally shaped ossicle was bony and hard and no trace of the short process and umbo characteristic of the handle of the malleus was found, it was though to be an abnormally developed os goniale.

Adult↗
PubMed1993

Dermoid cyst in the middle ear.

A case of a moderate essentially low tone unilateral conductive hearing loss without a previous history of secretory otitis media in a six-year-old female patient is described. The condition was found to be due to a dermoid cyst in the tympanic cavity, which was confirmed by pathological examination of the surgically removed specimen. This is the sixth documented case of dermoid cyst in the tympanic cavity.

Child↗
PubMed1993

Chemical blockage of cervical sympathetic trunks for facial palsy.

Impairment of microcirculation of the facial nerves is considered to play an important role in etiology of facial palsy, and the main emphasis of the conservative treatment is aimed at circulatory improvement. Therefore, at the pain clinic, improved blood flow to the facial nerve by chemical blockage of cervical sympathetic trunks (stellate ganglion block; SGB) is employed in treating patients with facial palsy. The circulatory effects of SGB were clinically determined in 20 patients with acute Bell's palsy, and the effects of chemical blockage of cervical sympathetic trunks on the tissue circulation of facial nerve were also experimentally evaluated in dogs. In the clinical study, the blood flow volume of the common carotid artery increased significantly in 5 minutes after SGB, and has reached its peak of 176.4% in 20 minutes. This significant increase continued up to 75 minutes. In the animal model experiments, the common carotid arterial blood flow volume increased immediately after performing experimental SGB with a peak rise of 143.5% in 15 minutes, and the significant increase continued up to 45 minutes. The blood flow volume in the facial nerve tissue also increased for 5 minutes with a peak rise of 115.2% in 20 minutes after SGB, and this significant increase persisted for up to 60 minutes. A marked increase was observed in the blood flow volume in the facial nerve tissue as well as through the common carotid artery. The circulatory improvement performed by SGB extended as far as the facial nerve itself. From the facts above mentioned, SGB is considered to be an extremely effective treatment for the Bell's palsy.

Adolescent↗
PubMed1992

A case of congenital ossicular malformation with mild auricular deformity: embryological and surgical considerations.

A case of bilateral congenital conductive deafness with mild auricular deformity is presented, and the anomalous structure deformity of the ossicles was multi-focal in this case, and a previous report indicates that ossicular malformation in the ear with congenital conductive deafness is multi-focal when the external ear is only slightly deformed. Bilateral ossicular reconstruction with replacement of the stapes yielded satisfactory results.

Acoustic Impedance Tests↗
PubMed1992

Animal model for ischemic facial nerve paralysis with selective vascular embolization.

An experimental model that reliably and easily produces acute ischemic facial nerve paralysis would be useful for the controlled study of treatment and to improve our understanding of the pathophysiology and treatment of facial nerve palsy. Most documented models that simulate clinical facial nerve palsy cause direct damage to the nerve. We describe an experimental model for ischemic facial nerve paralysis in the cat that employs arterial block of the internal and external maxillary and posterior auricular arteries using embolizing material (Avitene). All animals develop stable acute ischemic facial nerve palsy lasting for approximately 2 months. Electromyographic study of this model revealed that the site of the lesion resulting from selective embolization may be within the temporal bone. This model has the advantages of simplicity of technique, cost-effective use of cats, and reproducibility of facial nerve palsy.

Animals↗
PubMed1991

Neurophysiology of ischemic facial nerve paralysis in an animal model.

The establishment of an animal model for facial nerve paralysis is assuming increasing importance in clinical medicine and also in basic facial nerve research. We previously reported an animal model for ischemic facial nerve paralysis using selective vascular embolization through the internal maxillary and posterior auricular arteries in cats using Avitene which contains bovine microfibril collagen. In this paper, we determined the exact site of the lesion in established facial paralysis. A descending signal produced by direct stimulation to the contralateral motor cortex was able to elicit firing of the motor nucleus of the facial nerve, the extra-temporal portion of the peripheral nerve, and the orbicularis oris muscle. After achieving complete facial nerve paralysis, this descending signal was completely abolished within the temporal bone area, whereas peripheral facial nerve stimulation elicited a normal evoked electromyogram of the orbicularis oris muscle. The present results suggest that the site of the lesion of ischemic facial nerve paralysis produced by embolization in an animal model is within the temporal portion of the seventh nerve, and this animal model may lead to the advancement of future facial nerve research which cannot be conducted in humans.

Angiography↗
PubMed1990

Hyogo ear bank experience with allograft tympanoplasty--review of tympanoplasties on 68 ears.

Allograft tympanoplasties on 68 ears done between October, 1980 and December, 1986 were analyzed from the viewpoint of graft take rate and hearing improvement, and also the results were compared between draining and nondraining ears as well as among three stabilizing methods of the transplanted tympanic membrane (Type I: allograft tympanic membrane (ATM) covered with reflected epithelium; Type II: entirely covered ATM with fascia; and Type III: ATM reinforced with thin crescent fascia) and four groups of allograft materials (Group I: ATM with attached malleus and incus en bloc; Group II: ATM with attached malleus; Group III: ATM attached malleus and incus columella; and Group IV: two stage surgery with Group III material). Among the three types of stabilization in draining ears, the anatomic success rate of the tympanic membrane transplant was 27% in Type I, 56% in Type II and 90% in Type III, while in nondraining ears it was 81%, 88%, and 100%, respectively. The success rate for hearing improvement in draining ears was 40% in Group A, 44% in Group B, 33% in Group C, and in nondraining ears, it was 82%, 100%, and 82%, respectively. Our results show that allograft tympanoplasty can be successful for a well-controlled middle ear with good utility of the areolar fascia in stabilization.

Graft Survival↗
PubMed1989

Intractable retroauricular abscess associated with microtia and aural atresia--some views in relation to the congenital cholesteatoma and microtia.

Five microtic and aural atretic ears associated with intractable retroauricular abscess unresponsive to conservative treatment are reported. The pathogenesis of this abscess is primary cholesteatoma called "cholesteatoma auris congenita of atretic ear," and these lesions can be clearly explained by the embryological development of the external auditory meatus. Microtic ears with such lesions invariably have part of the cartilaginous canal patent but have an atrophic bony canal. Therefore, grade 3 microtia has never been affected theoretically. We also discuss the relationship between the retroauricular abscess and the development of the tympanic bone. The evaluation of this lesion with computed tomography is mandatory for the detection of an occult congenital cholesteatoma behind the atretic canal, and regular follow-up of the patients with microtia and aural atresia is necessary for plastic surgeons.

Abscess↗