Biomedical subjects

T Takasaka

Publications and source records attributed to T Takasaka.

At least 127 records · Page 7Linked to original sources

PubMed1995

Na+ transport processes in isolated guinea pig nasal gland acinar cells.

In the dispersed acinar cells of the submucosal nasal gland in the guinea pig, intracellular Na+ concentration ([Na+]i) was measured with a microfluorimetric imaging method and the cytosolic indicator dye, sodium-binding benzofuran isophthalate, under HCO3(-)-free conditions. In the unstimulated condition, the [Na+]i was averaged to 12.8 +/- 5.2 mM. Addition of 100 microM ouabain or removal of external K+ caused an increase in [Na+]i. Replacement of external Cl- with NO3- or addition of 0.5 mM furosemide reversibly decreased the [Na+]i. The recovery process from the reduced [Na+]i was inhibited by removal of either K+ or Cl- in the bath solution. These findings indicate the presence of a continuous influx of Na+ coupled with K+ and Cl- movement. Application of acetylcholine (ACh, 1 microM) caused an increase in [Na+]i by about 15-20 mM, which was completely inhibited by addition of 10 microM atropine. Increased cytosolic Na+ induced by ACh was extruded by the Na(+)-K+ pump. Removal of external Cl- and addition of 50 microM dimethylamiloride inhibited ACh-induced increase in [Na+]i by about 66% and 19%, respectively. In both unstimulated and stimulated state, Na(+)-K+ pump, Na-K-Cl cotransport, and Na(+)-H+ exchange play a critical role in maintaining intracellular electrolyte environment and in controlling a continuous secretion of nasal fluids.

Acetylcholine↗

PubMed1995

Cellular mechanisms in activation of Na-K-Cl cotransport in nasal gland acinar cells of guinea pigs.

The cellular regulation mechanism of Na-K-Cl cotransport was studied in dispersed acinar cells of the guinea pig nasal gland by a microfluorimetric imaging method using the Na(+)-sensitive dye sodium-binding benzofuran isophthalate. Addition of 1 micron acetylcholine (ACh) induced an immediate increase in intracellular Na+ concentration ([Na+]i) by 36.7 +/- 9.9 mM, which was almost completely abolished by the addition of atropine. The increased [Na+]i after cholinergic stimulation was due to the external (Cl-)-dependent cotransport system (about 80% of the total Na+ influx) and the dimethyl amiloride-sensitive (Na+)-H+ exchange system (of about 20%). The ACh-induced increase in [Na+]i was dependent on extracellular Ca2+ and was prevented by pretreatment with 8-(N, N-diethylamino)octyl-3,4,5-trimethoxybenzoate or O-O'-bis(2-aminophenyl)ethyleneglycol-N, N, N', N'-tetraacetic acid tetraacetoxymethylester. Addition of 1 microns ionomycin mimicked the ACh-induced increase in [Na+]i which was dependent on external Cl-. Moreover, both a calmodulin antagonist trifluoperazine and a myosin light chain kinase inhibitor ML-7 reduced the ACh-induced response in [Na+]i. However, the following treatment did not affect the basal [Na+]i nor the ACh-induced increase in [Na+]i: (i) addition of dibutyryl cAMP, 8-Br-cGMP, or phorbol 12-myristate 13-acetate, (ii) pretreatment of protein kinase inhibitors, H-89, H-8, H-7 or chelerythrine, (iii) prevention of cytosolic Cl- efflux by the addition of diphenylamine-2-carboxylic acid or, (iv) prevention of cytosolic K+ efflux by the addition of charybdotoxin.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

PubMed1995

Calcium mobilization and entry induced by extracellular ATP in the non-sensory epithelial cell of the cochlear lateral wall.

Effects of external ATP application on the intracellular Ca2+ concentration ([Ca2+]i) of the epithelial lining cells of the cochlear lateral wall, the stria vascularis (SV), spiral prominence (SP), and external sulcus (ES) cells, were examined by the fluorescent Ca2+ indicator, Fura-2. ATP induced an increase in [Ca2+]i of these epithelial cells loaded with Fura-2 in a dose-dependent manner (1-100 microM). The strongest response was observed in SP and ES cells, whereas SV cells showed a weak response. The increase in [Ca2+]i was a biphasic response consisting of a rapid transient peak followed by a sustained phase. Removal of the external Ca2+ caused a slight transient increase in [Ca2+]i without a subsequent sustained phase. The Mn2(+)-quenching method revealed the Ca2+ entry across the plasma membrane immediately after the ATP application. The initial peak results from both the release of Ca2+ from intracellular stores and the Ca2+ influx from the extracellular space. The sustained phase is totally derived from the external Ca2+. The effective order of purinergic agonists was 2-methylthio ATP > or = ATP > 3'-O-(4-benzoyl)benzoyl ATP > alpha, beta-methylene ATP > or = ADP, but adenosine or UTP showed no response. The ATP-induced [Ca2+]i response was inhibited by reactive blue 2. The [Ca2+]i was partially dependent on the concentration of the fully ionized form, ATP-4. These findings indicate the presence of both P2y- and P2z-purinergic receptors in the non-sensory epithelial cells of the lateral wall.

Adenosine Triphosphate↗

PubMed1995

ATP-induced increase in intracellular Ca2+ concentration in the cultured marginal cell of the stria vascularis of guinea-pigs.

The primary culture of marginal cells from the explant of the stria vascularis of guinea-pigs was established and confirmed by morphological, immunohistochemical and physiological characters of the cultivated cells. The positive stain of cytokeratin 18 without vimentin and desmin expressions indicated the epithelial origin of the cultured polygonal cells. Electron microscopical findings of cultured cells resembled the morphological characteristics of marginal cells. The addition of 100 microM ouabain to the cultured cells significantly increased the intracellular Na+ concentration, providing the evidence for the presence of Na+ pump. Using the cultured marginal cells identified by the above-mentioned findings, the effects of neurotransmitters and hormones in regulating intracellular Ca2+ concentration ([Ca2+]i) were investigated. The addition of 10(-4) M ATP caused an increase in [Ca2+]i, which was independent of the presence of extracellular Ca2+. The rank order of agonist potency was ATP > alpha, beta-methylene ATP > ADP. Adenosine, however, evoked no response. Cultured marginal cells may possess P2-purinergic receptors which mobilize Ca2+ from the intracellular Ca2+ pool.

Adenosine↗

PubMed1995

Carbohydrate distribution in the living utricular macula of the guinea pig detected by lectins.

Carbohydrate distribution in the fresh utricular macula of the guinea pig was analysed using lectins such as Concanavalin A (ConA), Dolichos biflorus agglutinin (DBA), peanut agglutinin (PNA), soybean agglutinin (SBA), Ulex europeus agglutinin (UEA-1) and wheat germ agglutinin (WGA) by means of confocal laser scanning microscopy. The ciliary bundle was strongly reactive to ConA, PNA, SBA and WGA but not to DBA and UEA-I, showing that the ciliary bundle has abundant D-galactose (GaI), N-acetyl-D-glucosamine (GlcNAc), D-mannose (Man) and sialic acid(s) (Sia) but not detectable amounts of L-fucose (Fuc) and terminal N-acetyl-D-galactosamine (GalNAc). Similar patterns of lectin bindings with moderate-to-weak intensities were observed on the non-cilial apical surface, on the surface of the otoconia and in the gelatinous layer of the otoconial membrane. On the contrary, the globular substance, a precursor of the otoconia, was scarcely reactive to any lectin examined, implying that it lacks glycoconjugates on its surface. Previous histochemical studies reported that the otoconial membrane possesses a much higher affinity for lectins that does the sensory epithelium (including the cilia) in the vestibular organ. This discrepancy suggests that factors in the preparation process may affect the otoconial membrane or the surface coat of the cilia to change their lectin affinity. Meanwhile, sialidase treatment augmented the affinity of the ciliary bundle for DBA and PNA, indicating that sialylated GalNAc and Gal are present on the vestibular ciliary bundle.

Agglutinins↗

PubMed1995

The effects of contralateral noise on masked compound action potential in humans.

The effects of contralateral noise on the masked compound action potential (CAP) were examined in human subjects. Small but significant enhancements of masked CAP amplitude (anti-masking effects) were observed in some patients with facial palsy, as well as in some subjects with healthy ears when noise was added to the contralateral ear. There were no significant differences in fractional changes of CAP by the addition of contralateral noise between subjects with healthy ears and patients with facial palsy in which acoustic reflexes of middle ear muscles (MEMs) had disappeared or were impaired. It is suggested that the anti-masking effects seen in the present study were possibly caused via the olivocochlear (OC) efferent system.

Acoustic Stimulation↗

PubMed1995

Biological characteristics of the globular substance in the otoconial membrane of the guinea pig.

Biological characteristics of the globular substance, which is considered to be a precursor of otoconia, were investigated by means of confocal laser scanning microscopy. The shape of the globular substance was a complete sphere, 3-10 microns in diameter. Its surface stained positively with both rhodamine 123 and DiOC6(3), implying similarity to intracellular organelles, whereas no fluorescence was seen when stained with chlortetracycline, a membrane-associated Ca2+ dye. Meanwhile, this substance showed very little affinity for six kinds of lectins, indicating the lack of a surface structure of carbohydrates. The fluorescence of fluo-3 in the globular substance increased markedly after the application of ionomycin. But this was completely inhibited by the depletion of external Ca2+. This reaction suggests that the surface of the globular substance exhibits characteristics of a biological membrane and that the influx of external Ca2+ occurs through membrane-combined ionomycin. Internal free Ca2+ concentration varied from 1.1 x 10(-9) to 1.6 x 10(-4) M, the geometric mean being 3.3 x 10(-7) M, which is higher than normal resting level of intracellular Ca2+ concentration but lower than the calcium content of the globular substance estimated by X-ray microanalysis in previous studies.

Animals↗

PubMed1995

Suppression of a nonselective cation conductance by substance P in cochlear outer hair cells.

Substance P (SP) hyperpolarizes outer hair cells (OHCs) of guinea pig cochlea. The cellular mechanisms of the SP response were investigated with the whole cell patch-clamp technique. SP induced outward currents in a dose-dependent manner at a holding potential of -60 mV in a concentration range between 3 x 10(-6) and 10(-4) M. SP decreased slope conductance between -60 and +20 mV. Ion substitutions in the external medium revealed that SP suppresses nonselective cation conductance with high permeability for Ca2+. The relative ion permeability of the channel modulated by SP was as follows: Ca2+ > Li+ approximately Cs+ approximately Na+ > Tris+. The potency of the agonist action was as follows: SP >> neurokinin A > neurokinin B. Peptide antagonists induced currents similar to those of SP. CP-96345, a selective nonpeptide antagonist for the neurokinin type 1 receptor, did not inhibit the SP-induced current. Intracellular dialysis of guanosine 5'-O-(2-thiodiphosphate) and pertussis toxin (PTX) suggests that a PTX-insensitive G protein is involved in the SP response. Neither the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid nor staurosporine (10(-6) M) affects the SP response. Local application of SP by a puffer pipette indicates that the SP receptors are distributed along the side of the OHC. These results suggest the possibility that the action of SP on the OHCs may not be mediated by the tachykinin receptors but rather by a tachykinin receptor-independent pathway. It is proposed that SP suppresses the nonselective cation conductance in the lateral wall of OHCs via a PTX-insensitive G protein.

Animals↗

PubMed1995

Intracellular Ca2+ responses induced by acetylcholine in the submucosal nasal gland acinar cells in guinea pigs.

We examined intracellular Ca2+ responses of the nasal gland acinar cells to clarify cellular responses and molecular events with regard to the regulatory mechanism of the nasal secretion. The acinar cells of the serous gland in the nasal septum of guinea pigs were obtained by meticulous and selective dissection with minimal contamination by epithelial lining cells after collagenase treatment. The dispersed acini were incubated in the oxygenated solution supplemented with fura 2 acetoxymethyl ester, and the intracellular Ca2+ concentration ([Ca2+]i) was measured by fluorescence ratio imaging microscopy. The application of acetylcholine (ACh) to the cells induced an initially rapid increased [Ca2+]i followed by a sustained plateau. The increase in [Ca2+]i induced by ACh was concentration dependent, ranging between 10(-8) and 10(-4) M. The [Ca2+]i response was completely inhibited by atropine, further indicating the involvement of muscarinic cholinergic receptors. Removal of external Ca2+ with addition of EGTA resulted in a transient increase without a sustained phase, and the transient increase was abolished by the intracellular Ca2+ antagonist 8-(diethylamino)-octyl-3,4,5-trimethoxybenzoate, indicating that this increase in [Ca2+]i was due to release from internal stores. The initial peak was not altered by changes in external pH, addition of adenosine 3',5'-cyclic monophosphate (cAMP), nor addition of phorbol 12-myristate 13-acetate (PMA) but was augmented by external K(+)-induced depolarization, suggesting that the transient increase was due to a changing in the binding affinity to inositol 1,4,5-trisphosphate. The sustained Ca2+ entry induced by ACh was inhibited by Ni2+, but not by nifedipine.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

PubMed1995

Effects of oxatomide and KW-4679 on acetylcholine-induced responses in the isolated acini of guinea pig nasal glands.

The antiallergic drugs oxatomide and KW-4679 were assessed to show inhibitory effects on ionic currents and intracellular Ca2+ concentration ([Ca2+]i) increase induced by acetylcholine (ACh) in isolated acini of the guinea pig nasal gland. Both K+ and Cl- currents evoked by ACh were inhibited by addition of oxatomide and KW-4679 at the concentration of 10(-5) M. KW-4679 (10(-5) M) inhibited the increase in [Ca2+]i induced by ACh, whereas no effect of oxatomide (10(-5) M) on Ca2+ responses was observed. These findings suggest that both drugs suppress electrolyte and fluid secretion in the nasal glands by different mechanisms.

Acetylcholine↗

PubMed1995

Inhibition of acetylcholine-evoked Cl- currents by 14-membered macrolide antibiotics in isolated acinar cells of the guinea pig nasal gland.

Recent clinical and experimental studies demonstrated that 14-membered macrolides suppressed fluid secretion from respiratory tract mucosa. The cellular mechanisms of acetylcholine (ACh)-induced electrolyte secretion in the acinar cell isolated from the guinea pig nasal gland were investigated by using a microfluorimetric imaging method and a patch-clamp whole-cell recording. The ACh-induced increase in intracellular Ca2+ concentration measured by the fura-2 method was little affected by three types of macrolides, josamycin (JM), erythromycin (EM), and roxythromycin (RXM). The ACh-evoked ionic currents were not inhibited by a 16-membered macrolide, JM, whereas both 14-membered macrolides, EM and RXM, significantly inhibited membrane conductance, especially inward currents, in a concentration-dependent manner. The ACh-induced Cl- current isolated by the ionic substitutional experiments was remarkably inhibited by EM and RXM. The order of inhibition was RXM > EM >> JM. Thus, 14-membered macrolides showed a direct inhibition of the Cl- conductance activated by ACh.

Acetylcholine↗

PubMed1995

Xanthine derivatives inhibit the increase in intracellular Ca2+ concentration induced by acetylcholine in nasal gland acinar cells of the guinea-pig.

Intracellular calcium is considered to play a major role in secretory responses of various exocrine cell types. We examined whether xanthine derivatives can inhibit Ca2+ mobilization and entry in secretory cells in the airways. Therefore, the inhibitory effect of xanthines in the intracellular Ca2+ concentration ([Ca2+]i) in the isolated submucosal acinar cells of the guinea-pig nasal septum was investigated by means of fluorescence ratio microscopy. The inhibitory effects on Ca2+ release from stores was examined in Ca(2+)-free conditions. Effects on Ca2+ entry were estimated by two different protocols; 1) the sustained phase in a long-term application of acetylcholine (ACh) and 2) the [Ca2+]i overshoot following removal of ACh in Ca(2+)-free conditions. Xanthine derivatives, 3-isobutyl-1-methyl-xanthine (IBMX), caffeine, and theophylline, significantly inhibited the increase in [Ca2+]i evoked by ACh; both mobilization from internal Ca2+ stores and Ca2+ entry from the external space. The rank order of potency of these xanthine derivatives was IBMX > theophylline > caffeine. The addition of dibutyryl-cyclic adenosine monophosphate (cAMP) and forskolin to nasal gland acinar cells failed to inhibit the ACh-evoked increase in [Ca2+]i. Furthermore, a protein kinase A inhibitor, H-89, did not affect the inhibitory effect of the xanthine derivatives. The action of xanthines on the present acinar cells did not involve Ca(2+)-induced Ca2+ release (CICR) or an interaction with purinergic receptors. Thus, xanthines have a direct inhibitory effect both on Ca2+ release and entry in nasal gland acinar cells, and might thereby have antisecretory activity within the airways.

Acetylcholine↗

PubMed1995

Anosmia following head trauma: preliminary study of steroid treatment.

Twenty patients with post-traumatic anosmia were subjected to olfactory function testing, including olfactory acuity tests using a T & T olfactometer and an intravenous olfaction test. T & T tests revealed complete loss in 14 patients. In the intravenous olfaction test, 14 patients showed no response and 5 patients showed abnormal responses. The severity of olfactory dysfunction showed no correlation with background factors such as the site of head trauma, the presence of the fracture of skull, the presence of unconsciousness, or the presence of head operation. As a preliminary study, seventeen patients were administered a corticosteroid, a topical nasal drop of 0.1% betamethasone for 12 patients and an oral administration of prednisolone for 5 patients. Four patients showed slight recovery of olfactory function following a corticosteroid therapy. Effects of corticosteroids on olfaction might be explained by regeneration of olfactory receptor cell axons and reestablishment of contact with cells in the olfactory bulb.

Adrenal Cortex Hormones↗

PubMed1995

[A case of extramedullary plasmacytoma of the epipharynx--pathological diagnosis using multiple supplementary methods].

A rare case of extramedullary plasmacytoma of the epipharynx is reported. A 76-year-old woman presented with a one-year history of postnasal drip. Physical examination revealed a mass lesion in her epipharynx without cervical lymph node swelling. Biopsy of the mass showed diffuse proliferation of plasma cells at the light and electron microscopic levels. Immunohistochemical examination demonstrated monoclonal exhibition of IgA and kappa-light chain in the tumor cells. Furthermore, in flow cytometric analysis, the tumor cells were found to be CD10- CD19- CD20- CD22- HLA-DR- CD38++ sIg- EMA+, a typical phenotype of plasmacytoma. Additionally, rearranged bands were identified in Southern blot analysis of the tumor extract using probes for immunoglobulin heavy chain and kappa-light chain. Serum myeloma-protein and urine Bence-Jones protein were negative. Bone marrow examination, X-ray examination, CT scanning and 67Ga- and 99mTc-scintigrams showed no other systemic lesions. She received irradiation of 58 Gy to the epipharyngeal area over 7 weeks, followed by transnasal endoscopic resection using KTP/532 laser. The patient is free of disease six months after surgery, and is currently under close follow-up.

Adult↗

PubMed1995

[Intracellular Ca2+ response induced by acetylcholine in the submucosal nasal gland acinar cells of guinea pigs].

We examined intracellular Ca2+ responses of nasal gland acinar cells in order to clarify cellular responses and molecular events with regard to the regulatory mechanism of nasal secretion. The acinar cells of the serous gland, in the guinea-pig nasal septum, were obtained by meticulous and selective dissection with minimal contamination of epithelial lining cells followed by collagenase treatment. The dispersed acini were incubated in an oxygenated solution supplemented with fura -2 acetoxymethyl ester and the intracellular Ca2+ concentration ([Ca2+]i) was measured using fluorescence ratio imaging microscopy. The application of acetylcholine (ACh) to the nasal gland acinar cells induced an initially rapid increase in [Ca2+]i followed by a sustained plateau. The increase in [Ca2+]i induced by ACh was concentration-dependent and ranged from 10(-8) to 10(-5) M. The intracellular Ca2+ response was completely inhibited by atropine, indicating the presence of muscarinic cholinergic receptors. Removal of external Ca2+ with addition of EGTA resulted in a transient increase without a sustained phase. The sustained phase of the [Ca2+]i increase induced by ACh was inhibited by Ni2+, but not by nifedipine. The initial phase seems to be due to mobilization from cytosolic Ca2+ stores while the subsequent sustained phase is dependent on the influx of external Ca2+ ions sensitive to Ni2+. We have demonstrated that increasing the Ca2+ gradient by elevating external Ca2+ accelerates Ca2+ entry, and that depolarization of cells due to elevated external K+ attenuates Ca2+ entry. These findings suggest that the Ca2+ entry process in nasal gland acinar cells is dependent on the electrochemical gradient across the membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

PubMed1995

[Statistical analysis of press-through-pack foreign body in the esophagus and its experimental investigation].

A statistical analysis was performed in patients with press-through-pack (PTP) foreign body in the esophagus encountered in the Department of Otorhinolaryngology, Tohoku University School of Medicine, from 1986 to 1993. Furthermore, the radiolucency of PTP and the possibility of mucosal injury of the esophagus by PTP were examined by experimental methods. We obtained the following results: 1) The incidence of PTP foreign body in the esophagus increased in the period from 1986 to 1994 as compared with that from 1978 to 1985. 2) PTP foreign body was lodged in the following area: cricopharyngeal narrowing > bronchio-aortic narrowing > hiatal narrowing. 3) Fluoroscopy with or without contrast material and flexible endoscopy were useful tools for diagnosis. 4) Direct esophagoscopy revealed mucosal erosion, hematoma, edema and intact mucosa in 14, 3, 3, and 6 patients, respectively. 5) The period of hospitalization was longer in patients with mucosal erosion than in those with intact mucosa. 6) The base of PTP made of aluminium could be detected as a radiopaque material by lateral projections, suggesting that PTP foreign bodies require roentgenograms made parallel to the base of PTP. 7) Histological study indicated that traumatic lesions in the extracted esophagus manually produced by the sharp corner of PTP were present in the mucosal layer and partially in the submucosal layer, suggesting that esophageal perforation by PTP was generated by additional factors such as secondary infection and iatrogenic trauma induced by esophagoscopy.

Adult↗

PubMed1995

Efficacy of systemic corticosteroid treatment for anosmia with nasal and paranasal sinus disease.

Systemic administration of corticosteroids was attempted in the treatment of olfactory loss resistant to topical corticosteroid treatment in patients with nasal and paranasal disease and post-upper respiratory infection. Significant efficacy was achieved with a short course of high-dose oral corticosteroids in patients with non-allergic sinus disease. On the other hand, anosmia induced by upper respiratory infection failed to respond to systemic corticosteroid treatment, suggesting permanent damage to the olfactory receptor cell. The underlying mechanism of effectiveness observed in patients with sinus disease may be explained by improvement of the mucosal thickening of the olfactory fissure, leading to the access of an odorant to the olfactory neuroepithelium.

Administration, Intranasal↗

PubMed1994

Ionic currents evoked by acetylcholine in isolated acinar cells of the guinea pig nasal gland.

The patch-clamp whole cell recording was used to demonstrate activation of membrane conductance to K+, Cl- and cations induced by acetylcholine (ACh) in the isolated acinar cells of the guinea pig nasal gland. A small outward K+ current at 0 mV and a large transient and sustained inward current at -90 mV were evoked by ACh and ACh-evoked reversal potential was about -3 mV nearly to Cl- equilibrium potential in 140 mM KCl in the pipette and physiological saline in the bath. The ionic substitutional experiments indicated that ACh-evoked inward currents were carried by both Cl- and cations. Both outward and inward currents evoked by ACh were almost completely abolished by removal of external Ca2+ and mimicked those evoked by a calcium ionophore A23187. These findings indicate that ACh-evoked membrane conductances are mediated by an increase in intracellular Ca2+.

Acetylcholine↗