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Biomedical subjects

M Amatsu

Publications and source records attributed to M Amatsu.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Histological study of the tracheal adventitia, perichondrium and annular ligament].

The trachea begins at the lower border of the cricoid cartilage and passes down to bifurcate into the left and right mainstem bronchi. The presence of tracheal invasion is crucial factor influencing the prognosis for patients with cancers of the thyroid gland, hypopharynx, esophagus, etc. In order to understand the manner of invasion of the above tumors, precise knowledge of the normal tracheal structure is indispensable. This study was undertaken to clarify the normal microscopic structure of the trachea. Five normal tracheal specimens obtained at surgery were examined histologically and immunohistochemically. The loose connective tissue around the trachea, known as adventitia, was divided into a loose outer and a dense inner layer by hematoxylin and eosin (HE) staining. This two-layer pattern was clearly seen near the annular ligament but was obscured away from it. The connective tissue of the inner layer ran obliquely to joint the connective tissue of the annular ligament and ended in the submucosal layer. This arrangement of connective fibers seems to play a role in allowing the trachea to stretch and bend. Tracheal cartilage is covered with a dense fibrous membrane known as the perichoundrium. Between the superficial fibrous membrane and mature cartilage cells lies zone of immature cartilage made up of oval or spindle cells, and the inclusion of this zone in the perichondrium has long been a subject of controversy. In our study, the zone was homogeneously stained red by the elastica van Gieson's stain and was clearly distinguished from other structures. Immunohistochemical staining revealed a wide distribution of type I and type III collagen on the fibrous membrane and the zone of immature cartilage cells, while mature cartilage cells did not show such collagen. Based on these findings, we conclude that the zone of immature cartilage cells belongs to the periochondrium, which thus contains two layers, an outer fibrous layer and an inner transitional layer of immature cartilage cells. Our conclusions are as follows: 1. Tracheal adventitia is divided into two layers, an outer loose and an inner dense fibrous layer. 2. Tracheal perichondrium also consists of two layers, an outer fibrous layer and an inner transitional layer. 3. The fibrous bundle originating from the adventitia joins the connective tissue of the annular ligament, probably in order to allow the trachea to stretch and bend.

Collagen↗
PubMed1995

Long-term potentiation of neurotransmission in the inferior colliculus of the rat.

Postsynaptic field potential was elicited in the central nucleus of the rat inferior colliculus after electrical stimulation to the lateral lemniscus. The inhibitory action of locally applied GABA on the potential was blocked by the systemic administration of picrotoxin, a GABAA antagonist (2.5 mg/kg, i.p.). After the administration of picrotoxin, the tetanic stimulation of 50 Hz for 20 s increased the amplitude of the field potential to over 120% of the original level in 10 min; this was maintained for 40 min, and formed the long-term potentiation (LTP). The tetanic stimulation alone, however, failed to enhance the amplitude. Thus, LTP was induced in the inferior colliculus only when GABAergic action was depressed.

Animals↗
PubMed1995

Role of the perforating vein in vascular pedicle of free forearm flap.

An innovation in the preparation of the vascular pedicle of the free radial forearm flap is presented. While the radial artery is commonly used as the arterial pedicle of the flap, either the cutaneous venous system or the radial comitant vein (deep venous system) is used as the venous pedicle. The perforating vein communicates between these two venous systems at the cubital fossa, and we confirmed its presence in all but one of more than 180 cases. When the vascular pedicle is dissected proximally to the perforating vein contained in the flap, the venous drainage of both the deep and cutaneous systems can be restored by anastomosis of only one vein: the cutaneous or the radial comitant vein. On the other hand, the flap can be raised with the radial vessels (without the cutaneous vein) at the start of surgery, and a large caliber cutaneous vein, such as the median cubital, the cephalic, or the basilic, can be used for anastomosis in cases where the cutaneous veins in the distal forearm are too thin, or where the radial comitant vein is composed of two thin separated veins. We believe that preserving the perforating vein would make the forearm flap more reliable and more convenient in reconstructive surgery.

Forearm↗
PubMed1995

The role of middle ear effusions and epidermal growth factor in cholesteatoma formation in the gerbilline temporal bone.

To study the process of aural cholesteatoma formation, we used gerbilline temporal bones to examine histologically the early stages of spontaneous cholesteatomas associated with experimentally induced otitis media with effusion (OME) following electric cauterizations of the eustachian tube. Epidermal growth factor (EGF) was then localized immunohistochemically in the pars flaccida of normal ears and the forming spontaneous cholesteatomas. Findings in the ears with the early spontaneous cholesteatomas were effusion inside the pars flaccida and hypertrophy and hyperkeratosis of the pars flaccida. Findings in the ears with experimental OME involved an effusion in the whole middle ear cavity as well as hypertrophy and hyperkeratosis in both the pars flaccida and pars tensa. The incidence of ear drum changes was higher in the experimental OME group than in control animals without cauterization. EGF was localized in the mucous layer of normal drums, the mucous layer and lamina propria of drums with hypertrophy alone, and all layers in drums with hypertrophy and hyperkeratosis. EGF was especially positive in the cytoplasms of transformed cuboidal cells. These findings suggest that EGF within the transformed mucous layer may play an important role as a biochemical factor in developing cholesteatomas.

Animals↗
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↗
PubMed1994

Neoglottic activity in tracheoesophageal phonation.

It has been generally accepted that the retropharyngeal wall protrudes into the lumen and forms a prominence during alaryngeal phonation. Although the prominence is thought to be responsible for the vibratory source, the relationship between the vocalization process and the dynamics of the prominence is not well known. This study is undertaken to clarify the above-described relationship during tracheoesophageal (TE) phonation, one of the most common forms of voice restoration following total laryngectomy. Electromyography (EMG) with simultaneous manometry and fiberoptic observation of the hypopharynx were done in 7 subjects who underwent TE fistulization at the time of laryngectomy. Fiberscopy revealed prephonatory closure of the hypopharyngeal lumen, and subsequently, a definite configuration of the lumen where diverted air can escape with mucosal vibration during phonation. The EMG disclosed a characteristic pattern that had two bursts of activity with an intervening quiet period. It may be concluded that TE phonation consists of two steps: The first step, associated with the first burst and regarded as the preparatory stage, consists of the hypopharyngeal closure which forms a small lumen. The second step, associated with the second burst and regarded as the phonatory stage, consists of the vibration of the neoglottis with a definite configuration which is maintained by the hypopharyngeal muscle contraction.

Aged↗
PubMed1994

[Mechanism of neoglottic adjustment for voice variation in tracheoesophageal speech].

Over the past 17 years, we have been performing tracheoesophageal (TE) fistulization for voice restoration following total laryngectomy. The purpose of this technique is to divert the exhaled air through the TE fistula into the hypopharynx where the inferior constrictor muscle forms the retropharyngeal prominence on which the neoglottis is located. It is generally accepted that both pulmonary power and laryngeal adjustment control voice frequency and intensity change in laryngeal phonation. Regularity at various pitches and voice intensities was seen in TE phonation, despite laryngeal adjustment being lost. Regular voice production with various pitches and intensities requires a regulatory mechanism for both pulmonary power and the neoglottis. This study was designed to clarify the mechanism of neoglottic adjustment in TE phonation. Ten speakers with TE fistula were subjected to aerodynamic and electrophysiological investigations. Tracheal pressure, fundamental frequency, intensity, and airflow rate were measured for easy phonation, a high-pitched voice, and a loud voice. Resistance and efficiency of the neoglottis were calculated from the data obtained. Electromyograms of the inferior constrictor muscle and tracheal pressure were simultaneously recorded when the pitch or intensity of the voice increased. Six of the ten subjects examined were able to produce a high-pitched voice. Tracheal pressure increased in all six, the airflow rate in four, and neoglottal resistance in five, as compared with the data obtained during easy phonation. Nine of the ten subjects examined were able to produce a loud voice. In all nine, both tracheal pressure and the airflow rate increased as compared with the values measured during easy phonation. Neoglottal resistance had no definite pattern in relation to voice intensity changes. Electrophysiological study demonstrated that the activity of the inferior constrictor muscle increased as tracheal pressure increased so as to raise the pitch or increase the intensity of the voice. These results indicate that the adjustment of neoglottic closure and stiffness produced by the inferior constrictor muscle has the role of varying the frequency or intensity of the voice.

Aged↗
PubMed1994

Immunohistochemical study of p53, EGF, EGF-receptor, v-erb B and ras p21 in squamous cell carcinoma of hypopharynx.

We have characterized 24 hypopharyngeal squamous cell carcinomas and 5 normal hypopharyngeal tissues by immunostaining with antibodies against epidermal growth factor (EGF), EGF-Receptor (EGFR), p53, v-erb B, and ras p21. The Avidin-Biotin Complex (ABC) technique was employed. Overexpression of p53 appeared in 17 of 24 cases of squamous cell carcinoma of the hypopharynx (normal mucosa: none, well differentiated: 60%, moderately differentiated: 71.4%, poorly differentiated: 71.4%). Some dysplastic mucosae surrounding cancer lesions showed overexpression of p53. EGF and EGFR tended to be expressed more strongly in carcinoma [EGF: 29.1% (well differentiated: 30%, moderately differentiated: 28.6%, poorly differentiated: 28.6%); EGFR: 50% (well differentiated: 60%, moderately differentiated: 42.9%, poorly differentiated: 42.9%)] than in normal mucosa (EGF: 0%, EGFR: 20%). The v-erb B stained positively in carcinoma [62.5% (well differentiated: 70%, moderately differentiated: 71.4%, poorly differentiated: 42.9%)] but negatively in normal mucosa. These data suggest that genetic mutations of p53 probably play an important role at an early stage of tumorigenesis, and that the networks of EGF, EGFR and v-erb B probably are involved in the development of hypopharyngeal squamous cell carcinoma.

Adult↗
PubMed1993

Dental implantation to free scapular bone flap used for mandibular reconstruction.

Three patients who underwent mandibular reconstruction with a free vascularized scapular osteocutaneous flap after tumor resection are presented. Dental reconstruction was performed on three patients by implanting an artificial dental root into the grafted bone. The procedures for dental implantation were done just as on a normal jaw, and did not require hospitalization of the patients. They were followed up for 3 to 5 years after dental reconstruction. They have been able to masticate and ingest in a virtually normal manner during these periods. They also showed good appearance of the reconstructed mandible and dentes. On the basis of these results, the indication and evaluation of this procedure are discussed.

Adolescent↗
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

Post-inhibitory excitation of adenosine on neurotransmission in guinea pig hippocampal slices.

The postsynaptic field potential (population spike potential; PS) was recorded from the granule cell layer of guinea pig hippocampal slices. Adenosine at low concentrations ranging from 10 nM to 1 microM enhanced the amplitude of PS, whereas at concentrations over 10 microM it inhibited the neurotransmission. There appeared to be a rebound phenomenon after the removal of adenosine at inhibitory concentrations and the amplitude of the PS overshot the initial amplitude (we called this post-inhibitory excitation; PIE). Neither depressants such as gamma-aminobutyric acid (GABA; 1 mM) nor sodium pentobarbital (100 microM) by itself induced PIE. After application of GABA or sodium pentobarbital together with adenosine (0.1 microM), however, removal of all agents could induce the PIE. PIE as well as the excitatory effect of adenosine at low concentrations was counteracted by application of H-7 (100 microM), melittin or polymyxin B, potent protein kinase C (PKC) inhibitors, suggesting that the excitatory effect of adenosine is mediated by a metabolic process involving PKC. These results indicate that PIE induced by adenosine at high concentrations is due to a mechanism similar to the excitatory effect induced by adenosine at low concentrations, and that during application of adenosine at high concentrations the excitation is masked by its potent inhibitory effect.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

[Conservative treatment of Hunt syndrome].

Based on the pathophysiology of Bell's palsy that edema as well as ischemia lead to both compression and hypoxia, Stennert employed high doses of cortisone and dextran and reported a high recovery rate. In the past 5 years, we have been treating patients with Bell's palsy and Hunt syndrome with a high dose of steroids or low-molecular dextran (SD therapy). SD therapy was administrated in 71 cases of Hunt syndrome, and the results were compared with those of a group of 36 patients who had been treated with orally administrated low-dose steroids. All patients with incomplete palsies recovered completely, regardless of the mode of treatment. In cases of complete palsy, 62% of patients recovered completely when treated with SD therapy. In contrast, 29% of the patients treated with orally administrated steroids recovered completely. These results indicate that for patients with complete palsy SD therapy is more effective than oral steroid therapy, while patients with incomplete palsy recover completely with oral steroids. On the basis of this study, oral steroids are best used in cases of incomplete palsy unless complete palsy develops. In these latter cases, we now believe that SD therapy should be started immediately.

Administration, Oral↗
PubMed1991

Conservative treatment of Bell's palsy with steroids and dextran-pentoxiphylline combined therapy.

In 1980, Stennert proposed for the treatment of Bell's palsy an infusion therapy consisting of initially high dosages of steroids in combination with low-molecular dextran and pentoxiphylline. Excellent results were reported as a consequence of administering this treatment scheme. This "steroid-dextran" medication was modified (SD therapy) and administered in 172 cases of Bell's palsy. The results were compared with those of a group of 59 patients who had been treated with orally administered low-dose steroids in combination with vasodilators, adenosine triphosphate and vitamins. All patients with incomplete palsies recovered completely, regardless of the mode of treatment. In cases of complete palsy, 87% of patients recovered completely when treated with SD therapy. In contrast, 68% of the patients treated with orally administered steroids recovered completely.

Dextrans↗
PubMed1991

Primary tracheojejunal shunt operation for voice restoration following pharyngolaryngoesophagectomy.

A primary tracheojejunal shunt operation was performed for voice restoration following pharyngolaryngoesophagectomy with free jejunum reconstruction for advanced hypopharyngeal cancer. A fistula was created between the membranous part of the trachea and the lower part of the transplanted jejunum. The membranous part of the trachea was tubed to construct the tracheojejunal shunt. All three patients who had the tracheojejunal shunt operation retained phonatory function. Pitch formation was seen in the voice waveform with use of the tracheojejunal shunt. No leakage was seen at all during deglutition and a swallowing function was obtained in all patients who had the tracheojejunal shunt.

Aged↗
PubMed1991

[Articulatory evaluation after mesopharyngeal reconstruction with the radial forearm flap].

Soft palate and tonsil (mesopharynx) play an important role on articulation and swallowing. We must take care not to restrict these physiological function when we reconstruct the mesopharyngeal defect after cancer ablation. In order not to restrict the postoperative function of mesopharynx, we take it the more important to preserve the function of the residual tissue rather than to rebuild the lost function. We took notice of pliable nature of the radial forearm flap and tried to reconstruct mesopharyngeal defect in five cases with this flap. We analyzed articulatory function and velopharyngeal closure in these cases, postoperatively. Articulatory function was assessed on the results of intelligibility test with 100 Japanese monosyllables. In four cases out of five, about 70% of syllables were accurately heard. According to the Hirose's standard of speech function after the operation of oral and/or oropharyngeal cancer, those four cases were evaluated also to be excellent. Whether the resection was done beyond the uvula or not, proved not to have anything to do with the postoperative speech intelligibility. Although speech intelligibility once went down immediately after the operation, it improved around six months later. The improvement might be due to the following facts; The forearm flap was cicatrized postoperatively, disturbing the mobility. After the softening of the cicatrix began, the flap gradually recovered flexibility, which enabled surrounding structure to move more smoothly. Articulatory dysfunction was characterized as plosives tend to be misunderstood as nasals or affricates. Concerning nasality, the velopharyngeal closure was examined by fiberscope. Perfect closure was seen in two cases, near-perfect in two cases, and insufficient in one case.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Epithelial migration in the healing process of tympanic membrane perforations.

The healing process in 10 human tympanic membrane perforations after trauma and 20 myringotomies was observed under the microscope and was photographed. The movement of the healing process was from the central portion of the perforation to the periphery and followed the same direction as the drum's epithelial migration. At the central portion of the perforation's margin, the keratin layer proceeded to the periphery and was followed by the epidermal cell layer. Only slight movement was observed at the peripheral portion of the perforation. Histopathological examination confirmed these observations. These findings demonstrate that epithelial migration on the tympanic membrane plays a great role in the healing of a perforation.

Cell Movement↗
PubMed1990

Malignant fibrous histiocytoma of the hypopharynx.

Malignant fibrous histiocytoma has been the most common soft-tissue sarcoma of late adult life. However, it is relatively uncommon in the head and neck. Furthermore, there has been no report of malignant fibrous histiocytoma of the hypopharynx in the literature. The first case of malignant fibrous histiocytoma of the hypopharynx is presented. The patient, a 70-year-old male, underwent extended laryngectomy and elective neck dissection with primary tracheoesophageal shunt operation and pharyngeal myotomy for voice restoration following total laryngectomy. For more than 2 years, there has been no evidence of the disease or metastasis. He has the satisfactory phonatory and swallowing function.

Aged↗