Biomedical subjects

T Takasaka

Publications and source records attributed to T Takasaka.

At least 73 records · Page 4Linked to original sources

PubMed1998

Relationship between cholinergic airway tone and serum immunoglobulin E in human subjects.

It has recently been shown that immunoglobulin (Ig)E facilitates the cholinergic bronchoconstrictor pathway in human tissue in vitro. However, whether this occurs in humans in vivo has not been clarified. In this study, the bronchodilator responses were examined to inhalation of a submaximal dose of the anticholinergic agent oxitropium bromide (600 microg) in normal and allergic subjects with various levels of total serum IgE. Values of the forced expiratory volume in one second (FEV1) for all subjects were greater than 80% of predicted, but were negatively correlated with serum IgE levels (p<0.01). Oxitropium bromide inhalation induced an increase in FEV1 that was significantly greater in allergic rhinitis patients with high serum IgE (155+/-20 mL (mean+/-SEM), p<0.05) than in healthy subjects (64+/-21 mL) or those with allergic rhinitis but low serum IgE (82+/-21 mL, p<0.05). In contrast, the effects of the inhaled beta2-adrenergic agent orciprenaline sulphate (2.25 mg) were not significantly different among the three groups. In conclusion, higher serum immunoglobulin E levels were correlated with lower values of the forced expiratory volume in one second, and anticholinergic agents, but not beta2-adrenergic agents, caused more pronounced bronchodilation in subjects with high than in those with low immunoglobulin E levels. These data suggest that serum immunoglobulin E may be one of the factors that determine the airway tone, possibly via cholinergic mechanisms.

Administration, Inhalation↗

PubMed1998

Surgical criteria for obstructive sleep apnea syndrome based on localization of upper airway collapse during sleep: a preliminary study.

Obstructive sleep apnea syndrome (OSAS) is defined as intermittent complete or partial upper airway obstruction during sleep, causing mental and physical effects. Localization of obstructions in the upper airways in OSAS patients provides indispensable information for the selection of surgical procedures. We measured the pressure within the upper airways during sleep in 6 patients with OSAS in order to select the surgical procedure. Five patients were found to have the airway collapse in the velopharynx, and in three of them underwent uvulopalatopharyngoplasty (UPPP) with tonsillectomy was performed. The remaining one patient, having an obstruction in both the velopharynx and hypopharynx, underwent laser-assisted midline glossectomy as well as UPPP. The 4 patients receiving the operation showed improvements in the sleep apnea index and the lowest oxygen saturation postoperatively. These findings suggest that pressure measurement may be a reliable tool for localizing obstructions in OSAS patients and may be used for determined the surgical option.

Adult↗

PubMed1998

The acoustic reflex for filtered broadband stimuli: a lesser contribution of the lower frequency neurons.

The effects of the cut-off frequency of the filtered broadband stimuli on the human acoustic reflex (AR) were examined to observe the relation between the area of excitation in the cochlea and the AR response. The results obtained have indicated that all the input from the cochlear region does not equally contribute to trigger the AR equally; i.e., there is a lesser contribution from the frequency region below 700 Hz.

Adult↗

PubMed1998

A case of basal cell adenocarcinoma of the parotid gland.

We present a 73-year-old female with an enlarged mass in the right parotid gland. Fine-needle aspiration cytology suggested pleomorphic adenoma. Diagnostic imaging revealed that the tumour had a well-defined margin arising from the deep lobe of the parotid gland. A total parotidectomy with preservation of the facial nerve was performed. The final histopathological diagnosis including immunohistochemical studies was basal cell adenocarcinoma, which is a recently defined entity and a rare epithelial neoplasm. No sign of local recurrence or metastasis 24 months postoperatively has been observed.

Adenocarcinoma↗

PubMed1998

Acute effects of combined administration of kanamycin and furosemide on the stria vascularis studied by distortion product otoacoustic emission and transmission electron microscopy.

Acute effects of kanamycin and/or furosemide administration on the stria vascularis of the guinea pig cochlea were assessed by distortion product otoacoustic emission (DPOAE) and transmission electron microscopy. Kanamycin alone failed to affect the DPOAE levels and ultrastructural changes. Furosemide alone caused a rapid but reversible fall of the DPOAE levels. No remarkable pathological changes in the strial vascularis were observed after a complete recovery of the DPOAEs. On the other hand, furosemide injection following kanamycin with a 2 hour interval resulted in two patterns of significant changes in the DPOAEs, namely, a sudden drop in the DPOAE levels 2 to 3 hours after furosemide injection and a gradual fall in the DPOAE levels immediately after the incomplete recovery from the furosemide-induced decrease of the DPOAE levels. Ultrastructural changes in the stria vascularis included numerous vacuoles in the strial marginal cells and increased electron density of the intermediate and basal cells. These physiological and morphological changes in the stria vascularis may imply new ototoxic features induced by kanamycin potentiated by furosemide.

Animals↗

PubMed1998

[Relationship between p53 gene expression and radiation effect in laryngeal carcinoma].

The purpose of this study was to determine the relationship between the biologic character of laryngeal carcinoma and the effects of radiation therapy. Using monoclonal antibody for p53 gene protein, 73 cases of laryngeal carcinoma were stained by the immunohistochemical DACO CSA System method. Results of the stain can be divided into intense, moderate and negative expression. There is a significant relationship between the gene expression and radiation effect. We found that samples which had higher level of staining due to increased gene expression, were affected more by the radiation therapy. The p53 gene expression can be useful in predicting the outcome of laryngeal carcinoma and be helpful in clinical therapy.

Carcinoma, Squamous Cell↗

PubMed1997

Expression and localization of the Na-K-2Cl cotransporter in the rat cochlea.

We identified the localization of the basolateral bumetanide-sensitive Na-K-2Cl cotransporter (BSC2) in the cochlea using an in situ hybridization method. In the rat cochlea, the BSC2 mRNA was mainly expressed in the strial marginal cells. Although the fibrocytes localized at the spiral prominence showed a weak expression of BSC2 mRNA, no expression was observed in the organ of Corti or spiral ganglion cells. The present findings are well consistent with a proposed cell model of ion transport in the marginal cell.

Animals↗

PubMed1997

Alternatively spliced isoforms of the Na+/Ca2+ exchanger in the guinea pig cochlea.

The cochlea has been suggested to express some Na+/ Ca2+ exchangers (NCX), since efficient acoustic transduction requires cytosolic calcium homeostasis. The present study revealed that several spliced isoforms of NCX are expressed in the guinea pig cochlea. Moreover, to determine their localization in the cochlea, microdissected RT-PCR was performed. The guinea pig cochlea was microdissected into three parts (lateral wall, the organ of Corti and modiolus). The cochlear lateral wall and the organ of Corti expressed only a single isoform of NCX1. On the other hand, five isoforms of NCX1 and four isoforms of NCX3 were detected in the cochlear modiolus. The alternative splicing may provide diverse functions for NCX in the cochlea.

Alternative Splicing↗

PubMed1997

Unilateral sinonasal disease without bone destruction. Differential diagnosis using diagnostic imaging and endonasal endoscopic biopsy.

OBJECTIVE: To evaluate the diagnostic algorithms leading to minimal-access surgery in unilateral sinonasal disease without evidence of bone destruction. DESIGN: In selected patients, we assigned qualitative preoperative diagnoses by performing computed tomography (CT), magnetic resonance imaging (MRI), and endonasal endoscopic biopsy and prospectively analyzed the results for 3 years, from 1992 to 1995. PATIENTS: Of 278 untreated patients who complained of nasal and sinus-related symptoms and underwent CT examinations, 130 were found to have unilateral sinonasal abnormalities without detectable changes in the bone structure. RESULTS: Accurate preoperative diagnoses were made using CT in 75% of the patients with chronic sinusitis with or without nasal polyps and 85% of the patients with mucoceles. In the remaining patients, preoperative diagnoses for both diseases were made using MRI. All fungal and vascular diseases were accurately diagnosed using MRI alone. Although neither CT nor MRI were useful in the qualitative diagnosis of neoplasm, the presence of neoplastic conditions, except papilloma, was indicated by MRI. Using endonasal endoscopy, biopsy was an accurate diagnostic tool, with minimal tissue damage, in 88% of the neoplasms. CONCLUSIONS: In differentiating untreated unilateral sinonasal disease without evidence of bone destruction, we conclude that CT is the first modality of diagnostic imaging and MRI is more sensitive than CT in identifying fungal disease and angiofibroma. Furthermore, MRI is helpful when neoplasm is indicated, but it is not an accurate diagnostic tool. The endonasal endoscopic approach for obtaining pathologic specimens is a qualitative diagnostic tool in the diagnosis of sinonasal neoplasm.

Adult↗

PubMed1997

Restoration of the mucociliary clearance of the maxillary sinus after endoscopic sinus surgery.

BACKGROUND: Whether endoscopic sinus surgery (ESS) restores the mucociliary clearance of the maxillary sinus needs further evaluation. METHODS: We evaluated the mucociliary clearance of the maxillary sinus by using a radionuclide technique in 12 patients with chronic sinusitis (sinusitis group) and in six patients who had undergone ESS 6 to 14 months after the surgery (post-ESS group). The mucosal cilia taken from the maxillary sinus in 12 patients with sinusitis before and after ESS (paired experiments) were examined by light and electron microscopy. RESULTS: The radionuclide placed endoscopically in the maxillary sinus in eight patients immediately after ESS maintained 81.2 +/- 16.3% of its radioactivity after 30 minutes. This result was consistent with results in four patients with untreated chronic sinusitis in whom the radionuclide had been instilled by antral puncture (86.9% +/- 3.5%). On the other hand, in six patients in the post-ESS group the radionucleotide maintained only 25.9% +/- 11.6% of its radioactivity, demonstrating statistically significant differences from those of both the sinusitis group without ESS (p < 0.005) and the group 4 days after ESS (p < 0.005). The absence of the cilia in the sinusitis condition was recognized in 35.5% +/- 12.1% (n = 12) of the epithelial cells. On the other hand, the absence of cilia was significantly (p < 0.01) reduced to 5.3% +/- 3.7% of the epithelial cells in the post-ESS condition. Electron microscopic observation also revealed abnormal cilia in the sinusitis condition, whereas the mucosal cilia were regularly arranged in the post-ESS condition. CONCLUSIONS: The mucociliary clearance of the maxillary sinus disturbed by chronic inflammation was restored by ESS, indicating the clinical effectiveness of ESS for the treatment of chronic sinusitis.

Adolescent↗

PubMed1997

Expression of voltage-dependent chloride channels in the rat cochlea.

Voltage-dependent chloride (ClC) channels have not yet been identified in the cochlea. In this study, an approach utilizing the reverse transcription-polymerase chain reaction (RT-PCR) was devised to clone the cDNA of ClC channels. PCR was performed using degenerate primers corresponding to two highly conserved regions of the ClC channels. By Southern hybridization and sequencing studies, the sequences corresponding to ClC-2 and ClC-3 were found in the cochlear lateral wall, while ClC-1 was not detected. These results suggest that ClC-2 and ClC-3 might be involved in Cl- transport in the cochlear lateral wall.

Animals↗

PubMed1997

Molecular and clinical implications of loop diuretic ototoxicity.

Recent advances in molecular biology have been applied to inner ear research. Loop diuretic ototoxicity has been suggested, but not proven, to share a common mechanism with diuretic effects on renal tubules. The discovery of the molecular nature of the Na-K-2Cl cotransporter in the cochlea provided a better understanding of loop diuretic ototoxicity. In this review, we describe clinical reports of loop diuretic ototoxicity and other information obtained by physiological, biochemical and morphological investigations related to the mechanism sensitive to loop diuretics. Based on recent evidence for the molecular nature of the Na-K-2Cl cotransporter expressed in the mammalian cochlea, the underlying mechanisms of ototoxicity induced by loop diuretics are described.

Animals↗

PubMed1997

Frequency summation observed in the human acoustic reflex.

It is known that the threshold of an acoustically induced middle-ear-muscle (MEM) reflex can be lowered by the simultaneous presentation of a second tone (facilitator), which is presented to the ipsilateral or contralateral ear at a level below the acoustic reflex threshold (ART) of the facilitator itself (Sesterhenn and Breuninger, 1976; Blood and Greenberg, 1981). In the present study, a primary elicitor and a facilitator were presented to the ear contralateral to that used for measurement of the acoustic reflex (AR), and the effects of changing frequencies and sound levels of the facilitator were investigated in human subjects with normal ears. The sound levels of facilitators, which caused a significant reduction of ART for the primary elicitors (facilitation thresholds), showed an asymmetrical pattern as a function of frequency of the facilitators. The facilitation thresholds tended to be lower when a facilitator with a frequency lower than the frequency of the elicitor (1 kHz) was used. In addition, effects of the elicitor on the masked thresholds of the facilitator were examined to observe the possible interaction between elicitor and facilitator from the viewpoint of 'spread of excitation'. The underlying mechanism of summation effects of two tones are discussed based on the possible input mechanism involved in the acoustically induced MEM reflex are.

Acoustic Stimulation↗

PubMed1997

Effect of anesthetic agents and middle ear pressure application on distortion product otoacoustic emissions in the gerbil.

The functional status of the middle ear system has a crucial importance in the measurements of distortion product otoacoustic emissions (DPOAEs), because each emission signal has to be detected indirectly in the external canal. It was observed that DPOAEs were scarcely detectable in the gerbil anesthetized with pentobarbital. On the other hand, when ketamine was used as an anesthetic, the DPOAE levels were generally high. The differences in the effects of these anesthetic agents on the DPOAEs became less clear when the tympanic bulla was opened. This strongly suggests that the effects might be due to a modification of the middle ear pressure. This study was designed to elucidate the mechanisms of the effects of these anesthetics on the DPOAEs. Comparing the effects of pentobarbital and those of pressure application to the middle ear on the frequency characteristics of DPOAEs, the following conclusions emerged: (1) pentobarbital administration causes negative middle ear pressure in the gerbil; (2) the generated pressure strongly reduces DPOAE conduction through the middle ear; and thus (3) proper selection of anesthetic agents is very important in gerbil experiments that involve OAE measurements.

Anesthetics↗

PubMed1997

Quantitative uronic acid analysis of the otoconial membrane of the guinea pig.

Histochemical and biochemical studies have shown that the otoconial membrane, as well as the tectorial membrane and the cupula, contains glycoproteins and proteoglycans. However, uronic acids, which are essential elements of glycosaminoglycans (GAGs), have not so far been directly detected or quantitatively measured in inner ear samples. In the present study, we quantitatively analyzed the glucuronic acid (GlcA) content of the otoconial membrane of the guinea pig by methanolysis combined with reversed-phase high-performance liquid chromatography (RP-HPLC). The utricular otoconial membrane was treated with thermolysin to separate the supernatant (OM-sup; gelatinous layer) and precipitate (OM-ppt; otoconia). The samples were then subjected to methanolysis followed by brief TFA hydrolysis, incubated with 1-phenyl-3-methyl-5-pyrazolone for labeling, and then analyzed by RP-HPLC coupled with the detection of UV absorbance at 245 nm. The GlcA contents of OM-sup and OM-ppt were 2.1 and 5.8 pmol/100 ng protein, respectively. Based on this result, GlcA-containing GAGs estimated as (GlcA+monosulfo-N-acetylhexosamine)n would be 1.0% of protein in OM-sup and 2.61% of protein in OM-ppt, indicating that this type of glycoconjugate is a minor component in both fractions. It is, accordingly, presumed that both the gelatinous layer and otoconia of the otoconial membrane have totally different properties from those of the tectorial membrane and cartilaginous matrix, which contain abundant GAGs.

Animals↗

PubMed1997

Age-related changes of the globular substance in the otoconial membrane of mice.

The globular substance, which occurs in the vestibular macula as a precursor of otoconia, was examined in aged mice in comparison with young adult mice. Dissected otoconial membrane from the utricular macula of C57BL/6J mice was loaded with fluo-3-AM, and directly observed under a confocal laser scanning microscope. Internal free Ca2+ concentration ([Ca2+]i) of the globular substance was determined through in situ calibration performed by superfusion with ionomycin and Mn2+. Total area of the otoconial membrane, average diameter of the globular substance, and [Ca2+]i showed no significant differences between young adult and aged groups. However, the number of globular substances in young adult mice was significantly larger than those of aged mice. These results suggest a reduced rate of otoconial formation in the aged vestibule, which would result in the sparseness of otoconia in the aged vestibule and lead to balance disorders commonly seen in elderly persons.

Acoustic Maculae↗

PubMed1997

Expression of adhesion molecules in nonallergic chronic sinusitis.

Endothelial and epithelial adhesion molecules are important in the recruitment of leukocytes to inflammatory sites. To determine the relationship between recruited leukocytes and adhesion molecules in the paranasal sinus mucosa of nonallergic chronic sinusitis, we surgically obtained mucosa from 16 patients and identified the expression of intercellular adhesion molecules (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, and P-selectin by immunohistochemistry. Neutrophils were significantly dominant in the nasal discharge as compared with eosinophils. The degree of neutrophil infiltration in the paranasal sinus mucosa was prominent in both intraepithelial and subepithelial areas as compared with the lamina propria. In each tissue site, the degree of infiltration of neutrophils was similar to that of eosinophils. These findings suggest that the tissue neutrophils actively and rapidly migrated into the lumen. All the adhesion molecules except VCAM-1 were expressed in the vascular endothelial cells. On the other hand, the surface epithelial cells showed the expression of only ICAM-1. The expression of ICAM-1 on the endothelial cells correlated with the degree of neutrophil infiltration in the mucosa The eosinophil infiltration was not dependent on any adhesion molecules examined here. It was concluded that ICAM-1 expression in the mucosa may be involved in neutrophil recruitment and may contribute to the establishment of the inflammatory cell distribution in the paranasal sinus of nonallergic chronic sinusitis.

Adolescent↗

PubMed1997

Inhibitory effect of macrolides on interleukin-8 secretion from cultured human nasal epithelial cells.

The mechanism of macrolide therapy in chronic sinusitis patients is unclear. The authors studied the effect of macrolides on interleukin (IL)-8 secretion from cultured human nasal epithelial cells. Epithelial cells harvested from the nasal polyps of patients with chronic sinusitis were primary-cultured, and secreted IL-8 in culture media was measured by enzyme immunoassay. The cells secreted considerable amounts of IL-8 constitutively and in response to lipopolysaccharide. The secretion was significantly inhibited by 10(-5) M of erythromycin, clarithromycin, roxithromycin, and josamycin. 10(-6) M erythromycin still showed the inhibitory effect, whereas the same concentration of josamycin did not. These results indicate that macrolide antibiotics may act as an immunomodulator to reduce IL-8 in inflammatory sites and, at least partially, account for the clinically discrepant effects between 14- and 16-membered ring macrolides in long-term low-dose therapy for chronic sinusitis.

Adult↗