Biomedical subjects

T Maeyama

Publications and source records attributed to T Maeyama.

At least 37 records · Page 2Linked to original sources

PubMed1998

Beaded nerve terminals in feline laryngeal mucosa.

To investigate the mechanism of airway defense reflex, beaded nerve terminals were studied by immunohistochemical techniques. In the supraglottic region the density of PGP 9.5-immunoreactive nerve fibers was the highest at the base of the glottic surface in the epiglottis, and in the glottic region it was the highest in the arytenoid region. In the subglottic region the number of positive nerve fibers was less than the number at the base of the glottic surface in the epiglottis, and when the laryngeal mucosa was processed with NaOH to dissolve the epithelium, it was possible to observe beaded nerve terminals more clearly. These beaded nerve terminals were found just beneath, in the epithelial basement membrane. Electron microscopic examination of beaded nerve terminals revealed a large quantity of secretory granules and mitochondria, suggesting that their structure is similar to that of nerve terminals. Thus these beaded nerve terminals may function as mechanoreceptors.

Animals↗

PubMed1998

Distribution and origin of the intraepithelial nerve fibres in the feline pharyngeal mucosa.

Sensory inputs from the pharynx play an important role in initiation of the swallowing reflex and in feedback control of motor activities. Using an immunohistochemical technique and denervation procedures, we examined the distribution and origin of the intraepithelial nerve fibres in the feline pharyngeal mucosa to clarify the role of the afferent nerve in swallowing. The posterior pillar was very densely innervated, and the posterior and lateral walls of the mesopharynx had a moderate nerve density. In contrast, the base of the tongue, the vallecula, the pharyngeal surface of the epiglottis, and the pyriform sinus had only a few nerve fibres. The epithelium of the rostral and caudal portions of the pharyngeal mucosa were innervated by the glossopharyngeal nerve and superior laryngeal nerve, respectively, with a borderline at the middle level of the epiglottis. A portion of the intraepithelial nerve fibres in the lateral and posterior walls of the mesopharynx originated from the pharyngeal branch of the vagus nerve. It is hypothesized that the intraepithelial nerve fibres that exist in densely innervated areas are related to the initiation of the swallowing reflex induced by stimulation of the pharyngeal mucosa.

Afferent Pathways↗

PubMed1998

Distribution of NADPH-diaphorase activity in the feline laryngeal mucosa.

We studied nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase activity in the feline laryngeal mucosa using a histochemical technique in an effort to clarify the role of nitric oxide (NO) in the larynx. Many NADPH-diaphorase-positive nerve fibres were distributed around the blood vessels and the laryngeal glands. The majority of neuronal cells in the intralaryngeal ganglia were NADPH-diaphorase-positive. It is likely that NADPH-diaphorase-positive nerve fibres around the blood vessels and glands in the laryngeal mucosa originate from the intralaryngeal ganglia, and that NO regulates circulation and secretion in the larynx.

Animals↗

PubMed1998

Ultrastructure of the myelinated nerve fibers in the feline laryngeal mucosa.

We studied the myelinated sensory nerve fibers in the feline laryngeal mucosa. Myelinated afferent nerve fibers (A-delta type) present in the lamina propria showed deterioration of the myelin sheath and Schwann cells under the basement membrane. Axons penetrated the basement membrane and entered the intercellular space of the epithelium. Nerve endings with many mitochondria and small clear vesicles existed in the intercellular space. No synapse-like structure was found between the endings and the surrounding epithelial cells. It is likely that these endings act as mechanosensitive receptors that respond to water or chemical stimuli and that participate in eliciting swallowing, coughing, and bronchoconstriction.

Animals↗

PubMed1998

Expression of B7-1, B7-2, and interleukin 12 in bleomycin-induced pneumopathy in mice.

BACKGROUND: The bleomycin-induced pneumopathy involves a T cell-mediated immune response. T cell activation requires both antigen/MHC recognition and costimulatory signals. The CD28 receptor on T cells with its ligand B7 represents one of the most important examples of this costimulation. Interleukin 12 (IL-12) has a strong synergistic effect with the B7-1/CD28 interaction on inducing proliferation and cytokine production in T cells. METHODS: In this study, we investigated the expression of B7-1, B7-2, and IL-12 in bleomycin-induced pneumopathy in mice using reverse transcription polymerase chain reaction (RT-PCR), RT in situ PCR, and immunohistochemistry. RESULTS: We observed concurrent upregulation of B7-1, B7-2, and IL-12p40 mRNA in the lung tissues at 1 h to 7 days after bleomycin instillation into the trachea. B7-1 mRNA and protein were found in bronchiolar epithelial cells as well as macrophages, B7-2 and IL-12p40 mRNA appeared to be expressed in mononuclear cells. CONCLUSIONS: These findings indicate that T cell-mediated immune response in this model involves the upregulation of B7-1, B7-2, and IL-12p40 mRNA, and also demonstrate the aberrant expression of B7-1 in bronchiolar epithelial cells.

Animals↗

PubMed1998

Endothelial cell apoptosis in lipopolysaccharide-induced lung injury in mice.

BACKGROUND: Studies have shown the importance of apoptosis in vascular injury in vitro. We postulated that apoptosis of the endothelium contributes to vascular injury in vivo and may be involved in acute lung injury. METHODS: To test this hypothesis, we investigated the incidence of endothelial cell apoptosis in acute lung injury induced in mice by the administration of lipopolysaccharide (LPS). Male ICR mice were administered LPS (20 mg/kg body weight) intravenously and sacrificed at specified times thereafter. RESULTS: Histologic findings were consistent with acute lung injury which increased with time from 3 to 48 h after injection. Electrophoretic analysis of DNA that was extracted from lung tissue and 3'-end-labeled with digoxigenin demonstrated a fragmentation of DNA starting at 6 h. In situ terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end-labeling (TUNEL) demonstrated DNA strand breaks in the endothelial cells. TUNEL also revealed DNA strand breaks in bronchial and alveolar epithelial cells as well as inflammatory cells in the interstitium. These TUNEL-positive cells appeared 6 h after injection. Electron-microscopic examination of the endothelium strongly suggested the morphological characteristics of apoptosis. CONCLUSION: Apoptosis was induced by LPS administration in endothelial cells in vivo. A role for such apoptosis is suggested in acute lung injury.

Animals↗

PubMed1995

Morphologic study of the laryngeal taste buds in the cat.

The distribution of laryngeal taste buds (TBs) and their neutral components in the cat were investigated by immunohistochemistry and electron microscopy. The antisera used in this study were against cytokeratin, protein gene product 9.5 (PGP9.5), neuron-specific enolase (NSE), S-100 protein, calbindin D, calcitonin gene-related peptide (CGRP), and substance P (SP). Taste bud cells were specifically immunoreactive to the antibodies of human cytokeratin subtypes 8 and 18 (CAM5.2). On observation with CAM5.2, TBs were seen distributed on the laryngeal surface of the epiglottis and spread caudally along the aryepiglottic folds, reaching peak density at the laryngeal side of the arytenoid tubercle. The PGP9.5 and NSE immunoreactivities were recognized in TB cells and nerve fibers, both within the TBs and in the subepithelial connective tissue. S-100 protein immunoreactivities were not found in any of the cells in the TBs but were found exclusively in the subepithelial neural elements. The calbindin-D, CGRP, and SP immunoreactivities were confined to a part of the neural elements that was very thin. Taste pores, taste villi, neuronal varicosity, and synapselike structures were observed by scanning and transmission electron microscopic study. From these results it is considered that the TBs act as a chemical receptor.

Animals↗

PubMed1994

Electron microscopic immunohistochemical study of intra-epithelial nerve fibers in the canine larynx.

Substance P (SP)-, calcitonin gene-related polypeptide (CGRP)-, and vasoactive intestinal polypeptide (VIP)-immunoreactive (IR) nerve fibers were observed in the epithelium of the canine subglottic region. To investigate the morphological differences among SP-, CGRP-, and VIP-IR nerve fibers in the epithelium, this study was performed by using immunohistochemical staining and electron microscopy, after which the origins of the nerve fibers were examined by denervation of the bilateral superior and inferior laryngeal nerves. SP- and CGRP-IR nerve fibers entered the epithelium through the basement membrane, ascended among the basal and ciliated cells, and reached under the epithelial junctional complex to terminate with varicosities. Furthermore, subsurface cistern-like structures or bouton en passant type synapse-like structures were observed among some varicosities of these nerve fibers and ciliated cells in the epithelial apical portion. On the other hand, VIP-IR nerve fibers entered through the basement membrane, and terminated with varicosities at the height of the middle portion of the subglottic epithelium. The varicosities of the VIP-IR nerve fibers were larger, and these varicosities had a greater number of synaptic vesicles than the SP- or CGRP-IR nerve fibers. After section of the bilateral superior and inferior laryngeal nerves, the SP- and CGRP-IR nerve fibers disappeared, while the VIP-IR nerve fibers were not affected. The density and distribution pattern of VIP-IR nerve fibers clearly differed from the SP- and CGRP-IR nerve fibers of sensory origin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Studies on the uronic acid-containing glycoproteins of Fusarium sp. M7-1: IV. Isolation and identification of four novel oligosaccharide units derived from the acidic polysaccharide chain.

Four novel oligosaccharide units were isolated from the acetolysis products of the acidic polysaccharide chain derived from the glycoproteins of Fusarium sp. M7-1. Their chemical structures were resolved mainly by 1H-NMR spectrometry in combination with methylation analysis and mass spectrometry. The results indicate that these oligosaccharide units originated from the side chains, GlcNAc alpha 1-->4GlcA alpha 1-->2(GlcNac alpha 1-->4)GlcA alpha 1-->2Gal, GlcNAc alpha 1-->4GlcA alpha 1-->2(GlcNAc alpha 1-->4)GlcA alpha 1-->2(GlcNac alpha 1-->4)GlcA alpha 1-->2Gal, ChN<--P--> 6Man beta 1-->4GlcA alpha 1-->2Gal, and Man beta 1-->2(ChN<--P-->6)Man beta 1-->4GlcA alpha 1-->2Gal linked together with the other units reported previously [Jikibara et al. (1992) J. Biochem. 111, 236-243] through beta 1-->6galactofuranoside linkages in the acidic polysaccharide chain.

Carbohydrate Conformation↗

PubMed1992

Intracordal injection increases glottic closing force in recurrent laryngeal nerve paralysis.

Glottic closing pressure during swallowing was measured in the cat with a catheter pressure transducer to study the effectiveness of intracordal injection in increasing glottic pressure in unilateral recurrent laryngeal nerve paralysis. Swallows were elicited by pouring water into the pharynx while the animal was under light anesthesia with ketamine. Peak pressure of the glottic closure for the control group during deglutition was 68.0 +/- 10.5 mm Hg (mean +/- standard deviation). Peak pressure decreased to 22.0 +/- 3.6 mm Hg just after sectioning of the unilateral recurrent laryngeal nerve, and rose to 39.8 +/- 8.3 mm Hg by silicon injection into the paralyzed vocal fold. In a study of chronic cases 1 month or more after unilateral recurrent laryngeal nerve section, peak pressure was 49.1 +/- 23.4 mm Hg, and varied widely from 21 to 92 mm Hg because of differences in the position of the paralyzed vocal fold and the degree of compensation by the unaffected vocal fold. In the group that had the paralyzed vocal fold fixed in the median position, peak pressure was almost the same as that of the control group. When the paralyzed vocal fold was fixed in either the paramedian or lateral position, peak pressure was 33.3 +/- 7.0 mm Hg. This value was significantly elevated to 45.8 +/- 10.4 mm Hg by injection of silicon, though it remained lower than that of the control. These results suggest that the decrease in glottic closing force during swallowing as a result of unilateral recurrent laryngeal nerve lesion is compensated for by the unaffected vocal fold to some degree and is improved by intracordal injection.

Acute Disease↗

PubMed1991

Effects of pulsatile flow pattern and each stage of pressure increasing, constant and decreasing, respectively upon inelastic deformation of blood vessel.

The aim of this study is to elucidate the relation of the inelastic expansive deformation of natural blood vessel and the degradation of elasticity to the time pattern of circulating pulsatile pressure flow. When pulsatile pressure amplitude (delta P = Pmax - Pmin) becomes smaller due to Pmin increasing, the blood vessel is subject to creep deformation. In this sense, pulsating pressure will play a role in avoiding creep effect. Fluctuation of maximum pressure Pmax will induce the increase of inelastic deformation and the decrease of rigidity of the blood vessel. The inelastic deformation and the decrease of rigidity in blood vessel is induced at the stage of pressure amplitude rising from a lower one to a higher, but not during pressure amplitude (delta P) kept constant nor at the pressure amplitude decreasing stage. In order to reduce the degradation of mechanical properties of blood vessel, it may be effective to avoid the increase of Pmin and the variability of Pmax.

Biomechanical Phenomena↗

PubMed1990

[Observations on the effects of Nd-YAG laser irradiation in the canine tongue].

Recently, the Nd-YAG laser has been widely applied for head and neck surgery. This medical instrument provides several advantages, including hemostatic efficacy and cutting capability which are dependent on manipulation. The purpose of this study is to discuss the clinical application of Nd-YAG laser in the field of oropharyngeal surgery. For this reason, the canine tongue is used in this study. After irradiation by Nd-YAG laser, observations were performed on histological findings, measurement of tissue temperature and changes in blood vessels. The results obtained are as follows: 1) Irreversible tissue changes were found in the center of the irradiated area, with other tissue degeneration occurring in the surrounding areas. 2) Within the coagulated degenerative area, blood vessels were completely embolized. 3) Temperature measurements revealed that there were minimal effects on the surrounding tissues. 4) The coagulated degenerative area was replaced by granulation tissue subsequently occurring after wound healing. 5) The Nd-YAG laser was useful for oral and paranasal surgery, because these diseases are localized in the cavity. 6) Non-contact type Nd-YAG laser was indicated for vaporization of the lesions and was particularly useful for vaporizing superficial benign lesions. In this case, close range, low power vaporization is recommended. Conversely, vaporization for hemangioma and/or malignant lesions were most effective with high power irradiation. 7) Contact type Nd-YAG laser might be suitable for cutting and excision of lesions, but careful attention must be given determining the safety margin for application in malignant lesions, because tissue degeneration when using contact type Nd-YAG laser is less reactive than in non-contact type.

Animals↗

PubMed1989

Localization of laryngeal motoneurons in the medulla oblongata of guinea pigs.

The distribution of motoneurons in the brain stem innervating the laryngeal muscles cricothyroid, posterior cricoarytenoid, and thyroarytenoid-lateral cricoarytenoid in the adult guinea pig was investigated. Horseradish peroxidase was injected into individual muscles or applied to the cut end of the superior laryngeal nerve and the recurrent laryngeal nerve. The laryngeal motoneuron pool of guinea pig is divided into two separate areas: the rostral retrofacial nucleus and the caudal nucleus ambiguus. Superior laryngeal and cricothyroid motoneurons were present only in the retrofacial nucleus, while recurrent laryngeal motoneurons were present in both the nucleus ambiguus and the retrofacial nucleus. Posterior cricoarytenoid motoneurons were located in the rostral and ventrolateral part of the recurrent laryngeal motoneuron pool in the nucleus ambiguus. The thyroarytenoid-lateral cricoarytenoid motoneurons partially overlapped the posterior cricoarytenoid pool and extended more dorsomedially and caudally in the nucleus. Our findings on the distribution of perikarya in the laryngeal motoneuron of the guinea pig are essentially the same as those of other mammals.

Animals↗

PubMed1989

Glottic closure during swallowing in the recurrent laryngeal nerve-paralyzed cat.

Glottic closing pressure and time were quantitatively analyzed during deglutition and in reflex glottic closure elicited by superior laryngeal nerve stimulation by means of a catheter pressure transducer in the cat. Duration and peak pressure of glottic closure during deglutition were 322.6 +/- 32.2 msec (mean +/- SE) and 57.5 +/- 6.0 mmHg, respectively, whereas peak pressure of the reflex glottic closure was 21.7 +/- 6.1 mmHg in control animals. When the recurrent laryngeal nerve was denervated unilaterally, decrease in peak glottic closing pressure on swallowing was only about 36%, whereas the peak pressure of reflex glottic closure was markedly diminished to 4.5 +/- 4.6%. When bilateral recurrent laryngeal nerves denervated, decrease in peak pressure during deglutition showed no greater significance than it did after unilateral denervation. Inferior constrictors myotomy in addition to bilateral recurrent laryngeal nerve denervation reduced peak pressure to nearly zero. These results indicate that on swallowing, the inferior constrictors cooperate with the intrinsic laryngeal adductors, thus playing a very important role in reinforcing glottic closure, a function that is unlikely during reflex glottic closure.

Animals↗

PubMed1989

The fine structure of intraepithelial free nerve endings in the canine vocal cord mucosa.

Innervation of the epithelium on the undersurface of the canine vocal cords was investigated by transmission electron microscopy. In the subepithelial lamina propria, nerve bundles containing unmyelinated fibers were observed. The nerve bundles, encircled by basal lamina, were enclosed by a thin connective tissue layer and by flattened fibroblast-like cells. With nerve bundles approaching the epithelium, the axons divided repeatedly and entered the epithelial layer. In the epithelial cells, nerve axons formed knob-like swellings that contained a small number of large granular vesicles and a large number of small agranular vesicles. A sensory function responsive to irritant chemical stimuli and to mechanical stimuli is presumed for these vesicle-containing nerve processes.

Animals↗

PubMed1989

Respiratory failure due to vocal cord dyskinesia in olivo-ponto-cerebellar atrophy.

We present a case of OPCA with severe respiratory failure due to vocal cord dyskinesia. This vocal cord dyskinesia was found by fiberoptic bronchoscopy and confirmed by laryngeal electromyogram. Tracheal fenestration and drug therapy of haloperidol were successful for clinical improvement. To our knowledge, this is the first report of vocal cord dyskinesia in OPCA. We emphasized that OPCA could complicate vocal cord dyskinesia, causing severe respiratory failure.

Bronchoscopy↗

PubMed1989

[Experimental study on the air streams in the paranasal sinus].

Air streams in the paranasal sinus were investigated using Nose-Sinus Model to contribute to the fundamental knowledge of aerosol therapy. The results obtained were as follows; 1. The velocity of air streams in the paranasal sinus was measured by Laser Doppler Anemometer and the visualization of streams was done by Laser Light Sheet method. 2. The amount of aerosol passed into the maxillary sinus is approximately in proportion to the sectional area of the ostium. 3. A considerable amount of aerosol passing into the sinus was noted under LLS technique applying positive pressure from the choana. From the above results, it is necessary for the effective entrance of aerosol into the sinus first to open the middle meatus wide and to add the intermittent pressure.

Aerosols↗

PubMed1989

[Objective examination of taste in man by measuring gustatory evoked potentials].

Taste is an indispensable sense as well as olfaction to spend a tasteful life. The objective method of examining taste has not yet been established. Previous attempts to get gustatory evoked potentials (GEPs) in men and animals failed by contaminating artifacts. Solving this problem, the following developments were done. 1) Avoiding tactile artifacts, the tongue was rinsed constantly with distilled water. 2) By recording and averaging the galvanic skin response (GSR) at the same time, its influence on GEPs was compensated. 3) For proper averaging by computer, conditions of precise onset, duration of stimulus, the shortest stimulus rise and fall times were fulfilled by magnetic valve system. The new gustometer is expected to be one of the standard objective methods of examining taste in clinical practice.

Adult↗