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Biomedical subjects

T Kumazawa

Publications and source records attributed to T Kumazawa.

At least 361 records · Page 20Linked to original sources
PubMed1986

Contribution of electrostatic and hydrophobic interactions of bitter substances with taste receptor membranes to generation of receptor potentials.

The effects of changed ionic environments on the frog taste nerve responses to the bitter substances were examined. The responses to quinine and strychnine carrying a positive charge were suppressed by an increase in ionic strength of stimulating solutions. It was concluded that electrostatic interaction of these positive bitter substances with the receptor membranes greatly contributes to the adsorption of the substances on the membranes and that this interaction was suppressed by an increase in ionic strength. The responses to neutral bitter substances (caffeine and theophylline) were unchanged by an increase in salt concentration. The zeta potential of the mouse neuroblastoma (N-18 clone), which was depolarized by various bitter substances similarly to a taste cell, was measured in the presence of the bitter substances. The zeta potential was a little changed by quinine and practically unchanged by strychnine, caffeine and theophylline. The membrane fluidity of the N-18 cell monitored with 2-(9-anthroyloxy)stearic acid was changed in response to the bitter substances, while the fluidity monitored with 12-(9-anthroyloxy)stearic acid or 1,6-diphenyl-1,3,5-hexatriene was unchanged. This suggested that the bitter substances are adsorbed on the hydrophobic region near the surface and induce a conformational change at the region. The depolarization by the bitter substances seems to stem from changes in the "boundary potential" at the region near the surface within the membrane interior.

Adsorption↗
PubMed1986

Laser surgery for allergic rhinitis.

The inferior turbinates of 140 patients with perennial allergic rhinitis were vaporized by a defocused carbon dioxide (CO2) laser beam, using specially designed handpieces. Among these patients, 131 showed improvement in subjective symptoms one month after laser surgery. Excellent or good results were obtained in 27 of 35 patients who were followed up more than one year after laser surgery. The histopathologic changes observed in the nasal mucous membrane after surgery were fibrous proliferation and scar formation in the superficial layer of the submucosa. This surgery can be done under surface anesthesia as an outpatient procedure, and it is painless, with no bleeding.

Adolescent↗
PubMed1986

Effects of urinastatin on cardiac energy metabolism in acute hemorrhage in rats.

Urinastatin, one of the trypsin inhibitors extracted from the human urine, has been reported to be useful in treating hypovolemic shock. We studied the effects of urinastatin on cardiac energy metabolism in acute hemorrhage in rats. The hemorrhage was produced by withdrawing blood (60 ml) from the abdominal aorta, and an equivalent volume of saline and 25,000 units/kg of urinastatin were injected over 5 min. The heart was then frozen quickly with liquid nitrogen, and high energy phosphates, lactate, pyruvate and glycogen contents were measured enzymatically. There was no significant difference in either ATP, lactate or pyruvate contents of the heart between the urinastatin-treated and the control groups. However, energy charge ([ATP + 0.5 X ADP]/[ATP + ADP + AMP]) and glycogen levels in the urinastatin-treated group were significantly higher than those in the control group. These findings suggest that urinastatin might produce a metabolic improvement in mitochondrial function and suppress the anaerobic glycogenolysis induced by circulatory deficiency in an acute hemorrhagic state.

Adenine Nucleotides↗
PubMed1986

Effects of naloxone on cardiac energy metabolism in acute hemorrhage in rats.

It has been reported that naloxone may be useful in the treatment of hypovolemic shock. However, the effects of naloxone on cardiac energy metabolism in acute hemorrhage have not been investigated. The effects of naloxone on myocardial metabolism were evaluated in the rat during acute hemorrhage with crystalloid resuscitation. Intramyocardial high energy phosphates, pyruvate, lactate and glycogen were measured. There was no significant difference in high energy phosphates, energy charge, lactate and glycogen contents between control, 1 mg naloxone and 10 mg naloxone groups. However, pyruvate level in hearts in the 10 mg naloxone group was significantly higher than that in control group. Therefore, naloxone reduced the lactate/pyruvate (L/P) ratio. Although naloxone did not improve the mitochondrial function, it improved the oxidation-reduction state in cardiac energy metabolism.

Animals↗
PubMed1986

Adrenergic innervation of the Eustachian tube. Histochemical and electron-microscopic study.

The presence of adrenergic nerves in the Eustachian tubes of guinea pigs was observed using the Falck-Hillarp fluorescence method. Abundant adrenergic nerve are forming networks around blood vessels in all tubal regions. Adrenergic fibers also surround the tubal glands. The precise locations of adrenergic nerve terminals in the tube were demonstrated by electron microscopy following application of a false transmitter. Adrenergic nerve terminals were found in abundance just beneath the smooth muscle layer of the arteries in each part of the tube and close to the myoepithelial cells of the tubal gland.

Adrenergic Fibers↗
PubMed1985

Localization of calcitonin gene-related peptide in the organ of Corti of the rat: an immunohistochemical study.

The localization of calcitonin gene-related peptide (CGRP)-like immunoreactive (CGRPI) structures in the cochlea was examined in the rat using immunocytochemistry. Numerous CGRPI fibers entered the organ of Corti in the intraganglionic spiral bundle and formed a dense fiber patch at the base of the inner hair cells. Much fewer, but still a significant number of CGRPI fibers were seen at the synaptic region of the outer hair cells. Since no immunoreactive cells were seen in the organ of Corti and spinal ganglion, these fibers may be one of the major components of the olivocochlear bundles originated from the superior olivary complex.

Animals↗
PubMed1985

Neuroblastoma cell as a model for a taste cell: mechanism of depolarization in response to various bitter substances.

The mouse neuroblastoma cell (N-18 clone) was used as a model for a taste cell. The N-18 cell was found to be reversibly depolarized by various bitter substances. The minimum concentrations of bitter substances which induced depolarization (threshold concentration) varied greatly with the type of the substance. There was a good correlation between the threshold concentrations for various bitter substances in the N-18 cell and those in the human taste responses. The input membrane resistance was little changed during the depolarization induced by the bitter substances. Replacement of Na+ and Cl- with impermeable ions had practically no effect on the depolarization response to the bitter substances and reduction of calcium concentration from 1.8 to 0.2 mM led to a slight increase in the responses. It was suggested that the depolarization of the N-18 cell by bitter substances mainly stems from changes in the phase-boundary potential at the outer surface of the cell.

Animals↗
PubMed1985

Naloxone-reversible respiratory inhibition induced by muscular thin-fiber afferents in decerebrated cats.

Stimulation of muscular thin-fiber afferents of cats causes two types of respiratory suppression: one is stimulus-locked suppression which is not affected by naloxone, and the other is naloxone-reversible respiratory suppression after cessation of the stimulation. Both types of respiratory suppression could still be evoked after decerebration of cats at the midcollicular level. The present experiment revealed that muscular thin-fiber afferents, presumably polymodal receptor afferents, caused respiratory inhibition mediated through an opiate system in the brain structure below the caudal part of the brain stem.

Animals↗
PubMed1985

Prognostic determination and submandibular function in Bell's palsy. Dynamic testing with technetium Tc 99m.

In 56 patients with Bell's palsy, a submandibular gland function test employing a dynamic technetium Tc 99m scan was performed, to study the relationship between the test results and the prognosis of paralysis. Patients who had no difference in function on the affected facial side compared with the healthy side during the test (performed within ten days after symptomatic onset) had a high rate of early improvement. Patients who showed no response to the salivary secretory stimulant administered had an incomplete recovery and were all considered for surgery. Prognosis within ten days after onset was possible in as many as 37 of the 56 cases.

Facial Paralysis↗
PubMed1985

Succinylcholine-induced ventricular arrhythmia during halothane anesthesia.

A case of ventricular tachycardia in a healthy child subsequent to onset of a succinylcholine infusion is described. A 9-year-old male patient was scheduled for an adenoidectomy and bilateral tonsillectomies. There was no history of cardiac arrhythmia. Anesthesia was induced by mask with nitrous oxide and halothane. Immediately after the infusion of 20 mg of succinylcholine, the heart rate was 150 beats/min and then the electrocardiograph (ECG) revealed a short run of ventricular tachycardia. The patient was given 1 mg of propranolol, and enflurane and 100% oxygen were administered. Soon after the propranolol was given, normal sinus rhythm returned. Ventricular tachycardia may occur after a single dose of succinylcholine in a healthy anesthetized child without predisposing disease.

Adenoidectomy↗
PubMed1985

Synthetic diagnosis of parotid tumor.

Computed tomography (CT), ultrasounds, and radioisotope scintigraphy (RI scinti) were applied before operation to 156 patients with parotid tumor, and the result of each test and/or the synthetic study of them were compared with the findings during operation and the pathological diagnosis of isolated tissue. CT was found to be a very effective diagnostic aid in determining the location of the tumor. CT and ultrasounds both provided adequately reliable information regarding the tumor content. For diagnosing the malignancy of the tumor, synthetic diagnosis using CT, ultrasounds and RI scinti had a high diagnostic accuracy. By using the above mentioned methods of diagnosis, an accurate preoperative diagnosis of the tumor could be obtained.

Diagnostic Errors↗