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Biomedical subjects

T Takasaka

Publications and source records attributed to T Takasaka.

At least 91 records · Page 5Linked to original sources
PubMed1997

Effects of extracellular ATP on ion transport and [Ca2+]i in Mongolian gerbil middle ear epithelium.

The present study investigates the effects of ATP on ion transport and Ca2+ mobilization in primary cultures of gerbil middle ear epithelium. Extracellular ATP and other nucleotides elicited a transient increase in short-circuit current (I(sc)) in a dose-dependent manner. The rank order of potency in I(sc) responses corresponded with the sequence of the P(2u) purinergic receptor when applied to the mucosal or the basolateral side. Extracellular ATP induced a rise in the intracellular Ca2+ concentration ([Ca2+]i) in a dose-dependent manner. A similar rank order of potency in the ATP-induced increases in [Ca2+]i was observed. The time courses of the [Ca2+]i responses induced by ATP closely paralleled those of the I(sc) responses. 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester greatly reduced the increase in the I(sc) and [Ca2+]i responses to ATP. Diphenylamine-2-carboxylate, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, quinidine, and Ba2+ significantly blocked the ATP-stimulated I(sc). Glibenclamide had no effect on the ATP-stimulated I(sc). These results are consistent with the hypothesis that extracellular ATP and other nucleotides induce Cl- secretion across the apical membrane in cultured gerbil middle ear epithelium by activation of the apical Cl- channels via multiple modes of regulation.

Adenosine Triphosphate↗
PubMed1997

P2 purinoceptor of the globular substance in the otoconial membrane of the guinea pig inner ear.

The biological characteristics of the globular substance, a precursor of otoconia, are unclear. In the present study, the ATP-induced internal free Ca2+ concentration ([Ca2+]i) changes of the globular substance and the ATP distribution in the vestibular organ were investigated using a Ca2+ indicator, fluo 3, and an adenine nucleotide-specific fluorochrome, quinacrine, by means of confocal laser scanning microscopy. [Ca2+]i showed a rapid and dose-dependent increase in response to ATP with a 50% effective concentration (EC50) of 16.7 microM. This reaction was independent of external Ca2+, indicating the presence of an internal Ca2+ reservoir. Neither adenosine, alpha, beta-methylene-ATP, 3'-O-(4-benzoylbenzoyl)-ATP, ADP, nor UTP evoked this reaction, whereas 2-methylthio-ATP induced an increase of [Ca2+]i with an EC50 of 14.4 microM. Moreover, P2 antagonists, reactive blue 2 and suramin, and a phospholipase C inhibitor, U-73122, inhibited the ATP-induced [Ca2+]i increase. These findings indicate the presence of a P2Y purinoceptor on the globular substance. In addition, granular fluorescence was observed in the quinacrine-stained macular sensory epithelium, indicating the presence of ATP-containing granules in this tissue. These results suggest that a paracrine mechanism involving ATP may exist in the macula and that this mechanism regulates the biological behavior of the globular substance.

Adenosine Diphosphate↗
PubMed1997

Ototoxic effect of erythromycin on cochlear potentials in the guinea pig.

The mechanism of hearing loss due to the administration of intravenous erythromycin was investigated in the albino guinea pig, and it was found for the first time that this drug causes cochlear dysfunction. The endocochlear potential (EP) and the cochlear microphonics (CM) recorded at the first cochlear turn transiently decreased when erythromycin was administered intravenously at dosages of 100 and 150 mg/kg. The averaged maximum decrease in EP was 16 mV (n = 5) and 33 mV (n = 5) for 100 and 150 mg/kg, respectively. The maximum decrease in the CM was about 25% when the EP reached its lowest value with the injection of 150 mg/kg. A complete recovery of the EP and CM ensured within 20 minutes after each erythromycin dose. The perilymphatic perfusion of 3 mmol/L of erythromycin decreased the EP and CM; however, in contrast to the intravenous administration, the decrease of the CM was nearly complete and both the EP and CM were irreversible. Hearing loss due to intravenously administered erythromycin could likely be attributle to the transient dysfunction of the stria vascularis, although concomitant dysfunction of the central auditory pathway cannot be excluded.

Animals↗
PubMed1997

Increase of Cl- secretion induced by Kampo medicine (Japanese herbal medicine), Sai-rei-to, in Mongolian gerbil middle ear epithelium.

Sai-rei-to, a type of Kampo medicine (Japanese herbal medicine), has been shown to be clinically effective in treating patients with otitis media with effusion. The effect of Sai-rei-to on the ion transport of the middle ear surface epithelium cultured from the Mongolian gerbil was investigated by using an Ussing chamber. Application of Sai-rei-to to the mucosal bath but not the serosal bath induced an increase in the short-circuit current (I(SC)) in the basal state. The increase in I(SC) was almost completely inhibited by addition of diphenylamine-2-carboxylic acid but not by amiloride, indicating enhancement of Cl- secretion. On the basis of the lack of changes in the intracellular Ca2+ concentration and a sideness of action, the effect of Sai-rei-to on I(SC) is thought to be a direct and selective activation on the apical Cl- channel.

Amiloride↗
PubMed1997

Effects of long-term low-dose macrolide administration on neutrophil recruitment and IL-8 in the nasal discharge of chronic sinusitis patients.

Effects of long-term low-dose macrolide administration were studied in patients with chronic sinusitis. Twelve patients with non-allergic chronic sinusitis were orally given 150 mg roxithromycin once a day without other treatments. The patients underwent computed tomography before and after the treatment, and paranasal sinus aeration was analyzed quantitatively. The number of neutrophils in the nasal smear was semiquantitatively assessed on a grading scale, and the IL-8 concentration in the nasal discharge was measured by enzyme immunoassay. The aeration of all four sinuses significantly improved, and recruited neutrophils and the IL-8 level in the nasal discharge were simultaneously reduced after the treatment. These findings suggest that long-term low-dose roxithromycin administration inhibits the positive feedback mechanism of neutrophil recruitment and IL-8 production by the recruited neutrophils, which is considered to be an essential cause of the prolongation of sinusitis.

Administration, Oral↗
PubMed1997

A case of leiomyosarcoma of the sphenoid sinus.

A 43-year-old man with a primary leiomyosarcoma of the left sphenoid sinus is presented. To our knowledge, this is an unusual case of leiomyosarcoma, which has never been reported in the literature. Accurate and safe diagnosis was obtained by an endonasal endoscopic approach with minimal tissue invasion.

Adult↗
PubMed1997

A case report of salivary duct carcinoma.

We present a 65-year-old man with an enlarged mass in the right parotid gland. A fine-needle aspiration cytology suspected Warthin's tumor. The ill-defined margin of the tumor in diagnostic imaging and unexpected clinical course of the occurrence of facial nerve paralysis suggested malignant neoplasm. The patient was treated with surgical resection of the primary site and neck following radiation therapy. Pathologic diagnosis was a salivary duct carcinoma. Difficulty in early diagnosis of this tumor may result in local extension, early metastasis to regional lymph nodes and distant sites, and death.

Adenocarcinoma↗
PubMed1997

A press-through-pack in the larynx.

A case of a 96-year-old male with a foreign body in the larynx is reported. The foreign body was a press-through-pack (PTP), a plastic packing for medicine, 16 mm x 16 mm x 3 mm in size. The PTP was safely removed from the larynx under general anesthesia.

Aged↗
PubMed1997

Middle ear inflation as a treatment for secretory otitis media in children.

Clinical evaluations of middle ear inflation for secretory otitis media (SOM) were performed with special emphasis on the influence of seasonal and aging factors. One hundred and forty-nine children between the ages of 3 and 9 years (227 ears) were all diagnosed as SOM by pneumatic-otoscopic findings, and type B tympanogram (TG) at 3 weeks or more after the onset of acute SOM or the initial observation of SOM. Middle ears were inflated by Politzer's method or by our modified method once or twice each week for 2 months. After inflation, TG displayed two different time sequences: one group changed to the A or C type immediately after inflating the ear one or more times, but usually returned gradually to the B type (TG-improved group): and the other group remained without any changes (TG-unchanged group) for the duration of this study. The healing rate in the TG-improved group was significantly higher than in the TG-unchanged group at the 2-month endpoint. The cure rate of SOM was significantly higher in spring than in autumn in the TG-unchanged group but not in the TG-improved group. There were almost no differences between the healing rates in the 3-5 and 6-9 year-old children. When a TG-unchanged ear is found in autumn during the 2-month inflation treatment, more careful and forcible treatments should be introduced later, especially to children between the ages of 3 and 9 years.

Child↗
PubMed1997

[Immunohistological study of infiltrating cells in nasal mucosa and nasal lavage fluid of perennial allergic rhinitis].

It is well known that EG2-positive cells, CD68-positive cells and other inflammatory cells significantly increase after antigen provocation in the nasal mucosa of an allergic patient. However, there are few reports of the immunohistological study if the infiltrating cells in nasal lavage fluid are not seen. In this study, the infiltrating cells in nasal mucosa as well as in nasal lavage fluid were immunohistologically examined by means of monoclonal antibodies 30 minutes after the antigen provocation. Seven patients with perennial allergic rhinitis were challenged by an antigen disk placed on one side of the inferior turbinates and each nasal cavity was irrigated separately 30 minutes after the antigen provocation. About seven days later, these patients were operated on and the nasal mucosa was removed 30 minutes after the antigen provocation. No marked change in CD4- and CD8 positive cells in the nasal mucosa and lavage fluid was found after provocation. On cytospin glass slides, there was a slight increase in the number of CD68 (P = 0.1), EG2 (P = 0.09), and neutrophil elastase positive (P = 0.2) cells. A significant increase in EG2-positive cells was also seen in the superficial layer of the lamina propria (P < 0.05) but not in the deep layer. CD22 positive cells were not seen on the cytospin glass slide, whereas many positive cells were observed in the deep layer of the lamina propria. These results indicate that EG2-positive cells participate strongly in the early phase of the allergic response after provocation in spite of the absence of significant changes in CD4- and CD8 positive cells. Immunohistological evaluation of nasal lavage is thought to be beneficial concerning the movement of each kind of cells. Each kind of cell is thought to fulfill the main physiological role in the epithelial layer or the lamina propria in early allergic inflammation.

Antigens, CD↗
PubMed1997

[Dynamic behavior of guinea pig middle ear].

The dynamic behavior of the middle ear was studied in living guinea pigs by using a laser Doppler vibrometer coupled to a compound microscope. Placing glass microbeads 20 microns in diameter on four points of the tympanic membrane and six points of the ossicles, their velocity amplitudes were measured under a constant stimulus of 65 dB SPL. Velocity responses of the four points on the tympanic membrane differed over the frequency range from 0.1 kHz to 3 kHz. At low frequencies, the malleus and incus rotated around an axis running from the malleus head to the incus short process. At middle frequencies, the whole ossicle had a piston-like motion. At high frequencies, the malleus and incus rotated around a vertical axis running through the ossicles, while the stapes had a hinge-like movement.

Animals↗
PubMed1996

Na+,K(+)-ATPase activity in the cochlear lateral wall of the gerbil.

We examined Na+,K(+)-ATPase activity in four regions of the gerbil cochlear lateral wall by measuring intracellular Na+ concentration ([Na+]i). The application of 1 mM ouabain and removal of external K+ caused a most striking increase in [Na+]i of the suprastrial fibrocytes, followed by the stria vascularis and the type II fibrocytes, but no detectable response in the type I fibrocytes. These results may imply the potency of the Na+,K(+)-ATPase activity. The high values of the resting [Na+]i in these cells under perilymph-like solution returned to the [Na+]i within physiological values after exposure to low-Na+ conditions similar to endolymph. Our results are interpreted in the light of recent morphological findings with regard to the roles in the secretion of K+ into endolymph of several cell types within the lateral wall.

Animals↗
PubMed1996

The Na-K-Cl cotransporters in the rat cochlea: RT-PCR and partial sequence analysis.

Nonsensory epithelial cells of the mammalian cochlea contribute to the production of the endolymph. The presence as well as the function of the Na-K-Cl cotransporter has been suggested, but not yet been proved. To identify the Na-K-Cl cotransporter isoforms expressed in the cochlea, mRNA was extracted from the cochlear lateral wall. After reverse transcription, resulting cDNA was amplified by polymerase chain reaction (PCR) with primers specific for Na-K-Cl cotransporter isoforms. In the rat cochlear lateral wall, mRNA homologous to the mouse bumetanide-sensitive Na-K-Cl cotransporter (mBSC2) was detected. These results suggest that the basolateral localization of the cotransporter in the marginal cell is involved in the secretory process of the endolymph.

Animals↗
PubMed1996

Subcellular distribution of protein kinase C in the living outer hair cell of the guinea pig cochlea.

Immunohistochemical staining using isoform-specific antibodies and intracellular localization using fluorescent probes for protein kinase C (PKC) were evaluated in the cochlear outer hair cell (OHC). Among three isoforms of classic PKC, PKC alpha was selectively stained in the fixed OHC as well as inner hair cells under a surface preparation method. Two types of fluorescent probes to detect subcellular localization of PKC were observed with a confocal laser scanning microscopy in the present study, fim-1 diacetate which binds to the ATP-competitive catalytic domain of PKC and Bodipy FL C12-phorbol acetate which binds to specific site localized to the first cysteine-rich loop of the C1 region in the regulatory domain. High fluorescence intensity of both dyes was observed in subcuticular and subsynaptic regions, infracuticular network, and along the lateral wall. The displacement experiments to evaluate binding specificity were performed by incubating Bodipy FL C12-phorbol acetate in the presence of 10 microM phorbol 12-myritate 13-acetate (PMA) and the fluorescence was totally disappeared. For the acute treatment of phorbol ester, cells were preincubated with 1 microM PMA 30 min before loading with fim-1 diacetate. The brightest area in the plasma membrane became much larger as compared with untreated cells, which suggests a dramatic translocation of PKC to the plasma membrane. The biological functions involving PKC in the OHC are discussed.

Adenosine Triphosphate↗
PubMed1996

Mechanism of neutrophil recruitment induced by IL-8 in chronic sinusitis.

BACKGROUND: The mechanism of neutrophil recruitment in patients with chronic sinusitis is unclear. OBJECTIVE: This study aims to elucidate the role of IL-8 in inducing neutrophil accumulation in the nasal discharge of patients with chronic sinusitis. METHODS: Nasal discharge and mucosal specimens were obtained from two groups of patients, those with chronic sinusitis and those with allergic rhinitis. The samples were subjected to immunohistochemical examination and in situ hybridization. The IL-8 level in the nasal discharge was measured by enzyme immunoassay. RESULTS: Immunoreactivity to IL-8 was observed in polymorphonuclear cells of nasal smear, in nasal gland duct cells, and in epithelial cells of the chronic sinusitis group; whereas those of the allergic rhinitis group mostly showed little or no reaction. Similar patterns of localization were shown by in situ hybridization for IL-8 messenger RNA. The IL-8 level in nasal discharge was significantly higher in the chronic sinusitis group than in the allergic rhinitis group. CONCLUSION: These results suggest that chemotactic factors in sinus effusion, including IL-8 derived from nasal gland duct cells and epithelial cells, attract neutrophils out of mucosa, and the neutrophils that have emigrated into the sinus effusion secrete IL-8. This induces further neutrophil accumulation in the sinus effusion of patients with chronic sinusitis.

Adolescent↗