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Biomedical subjects

H Fukuda

Publications and source records attributed to H Fukuda.

At least 793 records · Page 44Linked to original sources
PubMed1990

Effects of a new analog of thyrotropin-releasing hormone, N alpha-[(S)-4-oxo-2-azetidinyl) carbonyl]-L-histidyl-L-prolinamide dehydrate (YM-14673) on spinal reflex potentials and flexor reflexes in spinalized rats.

Experiments were performed on spinalized rats, transected at the Cl level. The intravenous administration of TRH and its analog YM-14673 (N alpha-[(S)-4-oxo-2-azetidinyl) carbonyl]-L-histidyl-L-prolinamide dehydrate) produced marked increases in the amplitude of mono- and polysynaptic reflex potentials and those of the withdrawal flexor reflexes. The effects of YM-14673 were stronger and longer-lasting than those of TRH. The stimulant action of TRH and YM-14673 on the flexor reflexes was not antagonized by prazosin, chlorpromazine, haloperidol or cyproheptadine, suggesting no involvement of the release of catecholamines or serotonin in the stimulant effects of TRH and its analog. Therefore, YM-14673 may be beneficial for the treatment of several spinal motor neuron diseases.

Animals↗
PubMed1990

Clinical assessment of therapeutic effects on cancer using 18F-2-fluoro-2-deoxy-D-glucose and positron emission tomography: preliminary study of lung cancer.

Using positron emission tomography, we studied the tumor uptake of 18F-2-fluoro-2-deoxy-D-glucose (18FDG) in five lung cancer patients before and after anti-cancer therapy (radiotherapy and/or chemotherapy). The tumor uptake of 18FDG was classified as positive and negative; the former, by increasing the uptake of 18FDG with time, and the latter, by decreasing or the constant uptake of 18FDG. Before therapy, all cases tested positive. After therapy, three cases were negative and two cases remained positive. All negative cases corresponded to complete second 18FDG study. Our findings in the 18FDG study correlate with the clinical results. 18FDG is a promising method for assessing therapeutic effects on cancer clinically.

Adult↗
PubMed1990

Electrophysiological and pharmacological properties of single spinal neurons isolated from adult bullfrogs.

1. We developed an isolated spinal cell preparation from adult bullfrogs. 2. The average resting membrane potential was -60 mV, and an action potential was activated by positive current injection. 3. The cells retained their tetrodotoxin-sensitive Na+ channels and at least two kinetically different types of K+ channel. 4. Under K(+)-free conditions, responses to GABA were blocked by bicuculline while responses to glycine, taurine or beta-alanine were blocked by strychnine. 5. The potency of excitatory amino acids decreased in the order: kainic acid greater than glutamate greater than NMDA. 6. These studies demonstrated that the isolated cells are applicable for electrophysiological and pharmacological investigations.

Amino Acids↗
PubMed1990

Displacement of the ventricular fold following cordectomy.

In order to avoid radiation and its undesirable side effects, we have employed surgical techniques for treatment of early glottic cancer when the lesion is confined to one membranous cord (Fukuda, Saito, Sato, and Kitahara: J. Jpn. Bronchoesophagol. Soc. 30: 7-14, 1979; Fukuda and Saito: Otologica 26: 434-436, 1980; Fukuda, Kawaida, Ohki, Kawasaki, Kita, and Tatehara: J. Jpn. Bronchoesophagaol. Soc. 39: 139-144, 1988). Laser is one of the most popular techniques and it has been accepted as the first choice by many authors (Annyas, Overbeek, Escajadillo, and Hoeksema: Laryngoscope 94: 836-838, 1984; Mcguirt and Koufman: Arch. Otolaryngol. Head Neck Surg. 113: 501-505, 1987; Tsuji, Fukuda, Kawaskai, Kawaida, and Kanzaki: Keio J. Med. 38: 413-418, 1989). However, some cases are difficult to approach by direct laryngoscopy, requiring an external way to expose the lesion. In these cases, cordectomy by laryngofissure is the method of choice, but the function of the glottis could be improved by replacing the excised cord displacing the ventricular fold. This technique, designed by the authors, was carried out in 22 patients and the results from the viewpoint of phonodynamics, voice quality, and cure rate are discussed in this study. The results are encouraging and we believe that this method is a very reasonable alternative to the laser when such equipment is not available. We also believe that late side effects and oncogenic problems associated with radiation are important points to be considered, especially in patients of relatively younger age.

Adult↗
PubMed1990

Dynamic movement of air tract fluid in lubrication of the larynx during phonation: a basic study using excised canine larynges and experimental air tract fluid by means of X-ray stroboscope system.

Experiments using excised canine larynges and experimental air tract fluid were conducted to clarify the movement of air tract fluid in association with vocal fold vibration by means of X-ray stroboscope system. It was thought that the movement of air tract fluid in lubricating of the larynx during phonation was closely correlated to vocal fold vibration, especially the wave motion of the mucous membrane of the vocal folds and the movement of air tract fluid on the glottis might be one of parameters to evaluate the flexibility of the mucous membrane of the vocal folds.

Animals↗
PubMed1990

Osteochondroma of the coronoid process of the mandible. Report of a case showing histological evidence of neoplasia.

A case of unilateral enlargement of the coronoid process of the mandible is presented. The patient, a 37-year-old woman complained of restricted mandibular movement and swelling in the left zygomatic region. Coronoidectomy was performed intraorally, producing improved mandibular movement. The specimen consisted of a large amount of cartilage and mature bone. Most of the cartilage showed a marked disturbance in endochondral ossification. The histopathological diagnosis was osteochondroma. A review of the basic nature of the disease in the reported cases is presented. The value of computed tomography in deciding on a surgical procedure is briefly mentioned.

Adult↗
PubMed1990

New norfloxacin resistance gene in Pseudomonas aeruginosa PAO.

A new type of norfloxacin-resistant mutant of Pseudomonas aeruginosa PAO was isolated. This mutant showed cross resistance to imipenem and chloramphenicol and hypersusceptibility to beta-lactam and aminoglycoside antibiotics. The new norfloxacin resistance gene nfxC was mapped near catA (46 min) on the PAO chromosome. Norfloxacin accumulation was decreased in the nfxC mutant; furthermore, the rate of imipenem diffusion through the outer membrane of the nfxC mutant was lower than that of the parent strain. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of outer membrane proteins showed a decrease of a 46-kilodalton protein and an increase of a 50-kilodalton protein in the nfxC mutant. We conclude the nfxC is a new norfloxacin resistance gene that affects outer membrane permeability to quinolones and other antimicrobial agents.

Bacterial Outer Membrane Proteins↗
PubMed1990

Infarction of the conus medullaris.

We encountered a patient with acute cauda equina syndrome. The clinical course, laboratory data and imaging study, including magnetic resonance imaging (MRI) strongly suggested that this episode was caused by a vascular disorder of the conus medullaris. We emphasized the diagnostic usefulness of MRI in the vascular disease of the conus medullaris as well as the clinical importance of this disease in the differential diagnosis of acute cauda equina syndrome.

Aged↗
PubMed1990

Frontal white matter lesions and dementia in lacunar infarction.

We studied the associations of mental deterioration and blood pressure with severity and location of lesions in the cerebral white matter of 35 patients (27 men and eight women) aged 52-84 (mean 70.9) years with multiple lacunar infarcts; 21 had no dementia and 14 were demented. Using magnetic resonance imaging to evaluate lesion severity, we determined that demented patients had more severe lesions than nondemented patients; this difference was especially prominent for lesions in the frontal lobe (p less than 0.001). Score on the dementia rating scale of Hasegawa et al was negatively correlated with severity of the lesions in the frontal lobe. Blood pressure was positively correlated with the severity of white matter lesions. We show that severity of lesions in the white matter, especially in the frontal lobe, is correlated with mental deterioration of patients with multiple lacunar infarcts. Because uncontrolled hypertension is related to the severity of such lesions, careful selection of antihypertensive treatment is important in preventing both the cerebral lesions and the associated mental deterioration.

Aged↗
PubMed1990

Spinal alpha 1- and alpha 2-adrenoceptors mediate facilitation and inhibition of spinal motor transmission, respectively.

The role of descending noradrenergic fibers in the spinal motor systems was investigated using spinal reflexes in acutely spinalized rats. In rats pretreated with the MAO inhibitor clorgyline-HCl (1 mg/kg, i.v.), L-3,4-dihydroxyphenylalanine (L-dopa) (5 mg/kg, i.v.), a precursor of dopamine and noradrenaline, markedly potentiated the mono- (MSR) and polysynaptic reflexes (PSR). Selective blockade of alpha 1-adrenoceptors by pretreatment with prazosin-HCl abolished these facilitatory effects on the MSR and the PSR and revealed the inhibitory effect of L-dopa on the PSR. The depression of PSR was antagonized by the alpha 2-antagonist piperoxan. Clonidine-HCl (0.05 mg/kg, i.v.), a so-called alpha 2-agonist, and tizanidine-HCl (0.1 mg/kg, i.v.) decreased the MSR and the PSR in rats pretreated with prazosin. These inhibitions were antagonized by piperoxan. These results suggest that alpha 1- and alpha 2-adrenoceptors mediate facilitation and attenuation of motor transmission in the rat spinal cord, respectively.

Animals↗
PubMed1990

Characteristic behavior of the respiratory muscles, esophagus, and external anal and urethral sphincters during straining, retching, and vomiting in the decerebrate dog.

To ascertain differences in the brainstem pattern generators for straining and retching, discharges of 230 respiratory single motor units from the intercostal nerves and discharges of the nerves to accessory respiratory muscles, the esophagus, and external anal and urethral sphincters were observed during straining, retching, and vomiting (fictive expulsion) in decerebrate and paralyzed dogs. Straining and retching were identified with coactivation of the phrenic nerve and the nerve to the rectus abdominis, which was elicited by distension of the rectum and stomach, respectively. Synchronous discharges with each retch and straining were always exhibited by the phrenic nerve, the nerves innervating the abdominal part of the rectus abdominis and the external anal and urethral sphincters. In contrast, different behaviours were constantly observed in four nerves. 1) The nerves to the serratus dorsalis cranialis was inhibited during straining, but activated synchronously with each retch and vomiting. 2) Vagal pharyngeal branches innervating the upper esophagus and branches of the recurrent nerve innervating the lower part of the cervical esophagus fired synchronously with straining. The esophageal nerves, on the other hand, did not fire with each retch, but did fire strongly between retches. 3) The nerve to the sacrocaudalis dorsalis lateralis discharged concomitantly with straining but did not with retches. Straining and retching behaviors exhibited by the nerves innervating other thoracic accessory inspiratory muscles (the intercartilagineus, rectus thoracis, scalenus) varied from dog to dog. The nerves innervating the thoracic parts of the rectus abdominis and obliquus externus abdominis always discharged synchronously with straining, and discharged with retches in the majority of dogs, but did not in a minority of dogs. The expiratory units from the internal intercostal nerves showed intense discharges synchronously with coactivation in straining (96%), retching (65%), and vomiting (100%). In contrast, none of the inspiratory units from the external intercostal nerves exhibited such intense discharges with straining and retching. These results suggest that the functional difference in straining and retching mainly depends on the differences in the behavior of the serratus dorsalis cranialis and esophagus. The forms of this dependence were discussed.

Anal Canal↗
PubMed1990

Laryngostrobovideography using a flexible laryngofiberscope performed in conjunction with the phonatory examination.

The phonatory examination was performed while monitoring vocal fold vibration by laryngostrobovideography. Vocal fold vibration was video-taped by a laryngostroboscope and flexible laryngofiberscope inserted through the nasal cavity. Simultaneously, the phonatory examination was conducted with a phonation analyzer. The data were entered into a personal microcomputer via an A/D converter and analyzed to obtain the parameters of sound pitch, sound intensity and mean expiratory air flow volume, which were superimposed on the color video monitor screen.

Fiber Optic Technology↗
PubMed1990

Assessment of procedures and instruments for intracordal injection: evaluation of the syringe for periodontal ligament anesthesia (CITO JECT).

The intracordal injection technique was first introduced by Brünings in 1911. This technique has been accepted as vocal rehabilitation for dysphonia caused by deficiencies of glottal closure. Although various injection materials have been evaluated, the injection procedure itself has not been studied. In this study, we measured the mechanical force required to perform intracordal injection by using a certain amount of substance, when varying the needle size and syringe type. Although a large needle can reduce the mechanical force for injection, leakage from the pinhole can not be prevented. We modified this technique by introducing a CITO JECT, a syringe, which is used for the anesthesia of the periodontal ligament, to perform the collagen injection. With this technique, the mechanical force required for the injection can be reduced to 1/2 to 1/4 of the force by the conventional technique. We conclude that the introduction of this syringe enable us to use the needle with smaller diameter to facilitate the intracordal injection.

Anesthesiology↗
PubMed1990

Further evidence for an essential histidyl residue at the active site of pig liver 5-aminolevulinic acid dehydratase.

Photoxidation with methylene blue and rose bengal and chemical modification by diethylpryrocarbonate of pig liver 5-aminolevulinic acid dehydratase produced strong inactivation of the enzyme which was concentration dependent. Loss of enzyme activity by both photoxidation and ethoxyformylation was pH and time-dependent and protected by the presence of the substate and competitive inhibitors. The rate of inactivation was directly related to the state of protonation of histidyl groups, the unprotonated from being modified at a much faster rate than the protonated form. Plots of the pseudo-first order rate constants for 5-aminolevulinic acid dehydratase inactivation against pH resulted in typical titration curves showing inflection points at about pH 6.4 for methylene blue and rose bengal and 6.8 for diethylprocarbonate providing further and unequivocal evidence for the existence of critical histidyl groups at the active centre of the enzyme.

Animals↗
PubMed1990

[On a minor component found in the lysozyme reference standard].

A minor component separated by HPLC from egg-white lysozyme was found to have a different substrate specificity from the main component, lysozyme. However, it did not show any difference in molecular weight and immuno-cross reactivity from lysozyme. There was no evidence based on our study that this minor component is an artificially-produced substance.

Animals↗
PubMed1990

[Control of spinal motor system by descending noradrenergic neuron].

The physiological function of the descending noradrenergic system in the spinal ventral horn has not yet been fully elucidated. Here we describe our recent findings showing the motor function of the noradrenergic fibers. 1) alpha 1-Antagonists and alpha 2-agonists depressed the spinal mono- and polysynaptic reflex potentials in rats that have an intact connection between the spinal cord and the brain. In rats spinalized at the Cl level, the alpha 1-agonistic action of adrenergic agents increased the spinal reflexes. 2) In the radio frequency-lesioned decerebrate rigidity model of rats, alpha 1-antagonists and alpha 2-agonists reduced the rigidity by affecting the spinal and supraspinal levels, respectively. 3) alpha 2-Agonists but not alpha 1-antagonists reduced noradrenaline released into the subarachnoid space of anesthetized rats. 4) In a slice preparation isolated from adult rats, the alpha 1-agonistic action of adrenergic agents increased the excitatory synaptic transmission of the ventral horn. Thus, it was demonstrated that alpha 2-agonistic action at the brain stem inhibited spinal motor activity by reducing the release of noradrenaline in the spinal cord, and that the facilitatory action through alpha 1-adrenoceptors was dominant in descending noradrenergic transmission in the motor nuclei of the ventral horn.

Adrenergic alpha-Agonists↗