Biomedical subjects

M Satoh

Publications and source records attributed to M Satoh.

At least 721 records · Page 40Linked to original sources

PubMed1992

Relationship between potency of L-isoprenaline and beta-adrenoceptor density estimated in single cells from tracheal smooth muscles of guinea pigs of different ages.

An age-related change in potency of L-isoprenaline in the presence of ascorbic acid, desmethylimipramine, corticosterone, pargyline, and phentolamine was obtained in tracheal strips from guinea pigs of differing ages between 6 and 40 weeks. The potency in the strips from 100-week-old guinea pigs did not significantly differ from that in strips from 40-week-old animals. Single cells were prepared from the tracheal muscles of 6-, 10-, 40-, and 100-week-old guinea pigs. The specific binding of [3H]dihydroalprenolol to the single cells was saturable. The dissociation constants of [3H]dihydroalprenolol were in good agreement with those of the membrane fractions from the guinea-pig tracheal muscles, and did not change with age. An excellent relationship between the potency of L-isoprenaline and the maximum binding of [3H]dihydroalprenolol estimated in the preparations from 6- to 40-week-old guinea pigs was found, suggesting that the increase in the potency of L-isoprenaline is due to the increase in the maximum binding or receptor density. The value in the preparations from 100-week-old guinea pigs deviated significantly from the regression line. This suggests the possibility that the decrease in potency in the strips from 100-week-old animals is due to a change in post beta-receptor processes in responsiveness.

Aging↗

PubMed1992

Hepatocellular carcinoma not detected with plain US: treatment with percutaneous ethanol injection under guidance with enhanced US.

To evaluate the usefulness of contrast material-enhanced ultrasound (US) in detection and treatment of hepatocellular carcinoma (HCC), carbon dioxide was injected as a contrast agent into the hepatic artery in 22 patients with HCC. Plain US had enabled detection of 24 HCC nodules in these patients. Contrast material-enhanced US enabled detection of seven additional nodules, which were confirmed as HCC by means of fine-needle aspiration biopsy performed under guidance with contrast-enhanced US. Six of these seven nodules were detected incidentally during examination of other suspected HCC nodules. Five of the seven nodules were treated with percutaneous ethanol injection (PEI) performed under guidance with contrast-enhanced US; the two other nodules were resected. Contrast-enhanced US made the HCC lesions visible for 15-60 minutes, sufficient time to mark the nodule with an iodized oil-ethanol solution for PEI. Because contrast-enhanced US enabled detection of additional nodules and performance of PEI in lesions not detected with plain US, it may help improve the treatment of HCC.

Adult↗

PubMed1992

Endothelin regulation of mucus glycoprotein secretion from feline tracheal submucosal glands.

We examined the effects of endothelin on both the trichloroacetic acid precipitable 3H-labeled glycoconjugate release and intracellular Ca2+ concentration ([Ca2+]i]) measured by the usage of fura-2 in submucosal glands isolated from feline trachea. Endothelin-1 produced a significant increase in glycoconjugate release from the isolated glands in a dose-dependent fashion, reaching a response of 161% of the control at 10(-6) M. Atropine, propranolol, phentolamine, or indomethacin did not produce any significant alterations in the ET-1-evoked glycoconjugate secretion from the isolated glands. In contrast, in tracheal explants which contained epithelium, ET-1 produced a significant reduction in the glycoconjugate secretion in a dose-dependent fashion, reaching a response of 59% of the control at 10(-6) M. In the presence of cultured epithelial cells, ET-1 also produced a significant reduction in the glycoconjugate secretion from isolated glands. In isolated glands, ET-1 produced a sustained increase in the [Ca2+]i which was abolished by the removal of Ca2+ from the medium or by the presence of cultured epithelial cells. Pretreatment with indomethacin failed to alter the epithelial inhibitory action evoked by ET-1 in both the glycoconjugate secretion and the [Ca2+]i in isolated glands. ET-2 and ET-3 failed to produce significant alterations in the glycoconjugate secretion or [Ca2+]i. These findings indicate 1) that ET-1 induces mucus glycoprotein secretion via a Ca2+ influx and 2) that it possibly augments the an epithelial action inhibitory to the mucus glycoprotein secretion from airway submucosal glands.

Animals↗

PubMed1992

Muscarinic receptor subtypes in feline tracheal submucosal gland secretion.

To determine what muscarinic receptor subtype regulates [Ca2+]i mediating airway submucosal gland secretion, we examined the effects of atropine (Atr), pirenzepine (PZ), 11([2-(diethylamino)methyl-1-piperidinyl] acetyl)-5,11-dihydro-6H-pyrido (2,3-b)(1,4)-benzo-diazepin-6-one (AF-DX116) and 4-diphenylacetoxy-N-methyl-piperidine methiodide (4-DAMP) on methacholine (MCh)-evoked [Ca2+]i rise in acinar cells, and compared this with mucus glycoprotein (MGP) and electrolyte secretion evoked by MCh from submucosal glands isolated from feline trachea. [Ca2+]i was measured with the Ca(2+)-sensitive fluorescent dye, fura 2. We determined MGP secretion by measuring TCA-precipitable 3H-labeled glycoconjugates and electrolyte secretion by the change in the rate constant of 22Na-efflux from isolated glands. Half-maximal inhibitory concentrations (IC50) of PZ, AF-DX116, 4-DAMP, and Atr against MCh-evoked [Ca2+]i rise were 10(-7) M, 6 x 10(-6) M, 8 x 10(-9) M, and 6 x 10(-9) M, respectively. IC50 of PZ, AF-DX116, 4-DAMP, and Atr against MCh-evoked MGP secretion were 10(-6) M, 2 x 10(-5) M, 8 x 10(-9) M, and 6 x 10(-9) M, respectively. MCh (10(-5) M)-evoked 22Na efflux was significantly inhibited by 10(-7) M 4-DAMP and 10(-7) M Atr (P less than 0.01, each) but not by 10(-7) M PZ. Receptor binding assays with [3H]quinuclidinyl benzilate showed that the Ki values for PZ, AF-D x 116, 4-DAMP and Atr were 2.2 x 10(-8) M, 6.6 x 10(-7) M, 6.2 x 10(-10) M, and 2.9 x 10(-10) M, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Effects of pharyngeal lubrication on the opening of obstructed upper airway.

We examined the effect of electrical stimulation of the hypoglossal nerve and pharyngeal lubrication with artificial surfactant (Surfactant T-A) on the opening of obstructed upper airway in nine anesthetized supine dogs. The upper airway was isolated from the lower airway by transecting the cervical trachea. Upper airway obstruction was induced by applying constant negative pressures (5, 10, 20, and 30 cmH2O) on the rostral cut end of the trachea. Peripheral cut ends of the hypoglossal nerves were electrically stimulated by square-wave pulses at various frequencies from 10 to 30 Hz (0.2-ms duration, 5-7 V), and the critical stimulating frequency necessary for opening the obstructed upper airway was measured at each driving pressure before and after pharyngeal lubrication with artificial surfactant. The critical stimulation frequency for upper airway opening significantly increased as upper airway pressure became more negative and significantly decreased with lubrication of the upper airway. These findings suggest that greater muscle tone of the genioglossus is needed to open the occluded upper airway with larger negative intraluminal pressure and that lubrication of the pharyngeal mucosa with artificial surfactant facilitates reopening of the upper airway.

Airway Obstruction↗

PubMed1992

Endothelin-1 stimulates chloride secretion across canine tracheal epithelium.

Although much attention has been paid to the effect of endothelin on the bronchopulmonary system, there are few reports concerning the effect of endothelin on Cl- secretion across airway epithelium. We examined the effects of endothelin-1, -2 and -3 on bioelectric parameters of canine tracheal epithelium, a tissue in which Cl- is actively secreted and Na+ is absorbed. Potential difference (PD) and short-circuit current (SCC) were measured using an Ussing chamber with 0.5 cm2 of exposed area, and conductance (G) was calculated by dividing SCC by PD. Luminal endothelin-1 produced transient increases in PD and SCC, returning to baseline values within 5 min after stimulation in a dose-dependent fashion and reached mean responses of 123 and 126% of baseline PD and SCC, respectively, at 10(-6) M of endothelin-1, whereas submucosal endothelin-1 did not alter PD and SCC. G remained unchanged when stimulated by endothelin-1. Endothelin-2 and -3 did not produce any significant alterations in PD and SCC. Endothelin-1 evoked increases in PD and SCC, which were not altered by pretreatment with luminal amiloride (10(-4) M), or by treatment with submucosal propranolol (10(-5) M). Ionic substitution of Cl- with nontransported anions, iodide and gluconate, inhibited endothelin-1-induced increases in PD and SCC. Pretreatment with 10(-5) M indomethacin partially inhibited Endothelin-1-evoked increases in PD and SCC. These findings indicate that endothelin-1 stimulates Cl- secretion partially through the generation of cyclooxygenase products of arachidonic acid.

Amiloride↗

PubMed1992

Glycolipid expression in prostatic tissue and analysis of the antigen recognized by antiprostatic monoclonal antibody APG1.

The expression patterns of glycolipid from prostatic hyperplasia, prostatic cancer and normal prostate tissue were observed. A further analysis of antigen recognized by mouse monoclonal antibody APG1, which was gained by immunizing glycolipids extracted from human prostate cancer, was also performed. In cancer tissue, both of the lactosyl and globoside series glycolipids were found to be generally reduced, although in the ganglioside series, GM3 and GD3 were not reduced and only the glycolipids with longer chains than GD2 were found to be reduced. These results indicated that the inhibition of sugar chain elongation, but not sialylation, was the main synthetic change occurring with carcinogenesis of the human prostate. APG1 reacted with only two bands near GM2 and GD2 of the ganglioside fraction on a thin-layer chromatography plate, but it did not react with any of the known gangliosides of the ganglioside series including GM2 and GD2. Histochemically, APG1 showed intense reaction only in frozen tissue sections of human prostate, and the reactivity decreased with the increasing grade of cancer. Therefore, this antigen was considered to be a prostate-specific and differentiated antigen reacting with nonganglioseries gangliosides.

Antibodies, Monoclonal↗

PubMed1992

Tumor size of renal cell carcinoma: its clinical implication.

We studied the clinical implication of tumor size in renal cell carcinoma, by revealing its relation with the other histopathological and clinical features. The tumor size was well correlated with histopathological findings and metastatic status of the carcinoma. Smaller carcinomas (usually less than 60 mm) generally had a higher disease-specific survival than those of 60 mm or greater. The results indicated that the size reflected the biological character of the carcinoma. However, 10% of patients with the smaller carcinoma had lymph node metastasis or distant metastasis at the time of diagnosis, each of which contributed to a renal cell carcinoma-related death in the early follow-up period.

Carcinoma, Renal Cell↗

PubMed1992

Bilateral metastatic sclerochoroidal calcification in a patient with hyperparathyroidism.

We present the case of a 39-year-old man with bilateral sclerochoroidal calcification with primary hyperparathyroidism. Both the calcium and parathyroid hormone levels were elevated. Funduscopic examination revealed slightly elevated, multiple yellow lesions in both eyes. Fluorescein angiography showed filling defects of the choroid. Ultrasonography showed elevated, highly reflective lesions, and a computed tomography scan of the globe disclosed sclerochoroidal lesions with high density. We discuss the mechanism of sclerochoroidal calcification.

Adult↗

PubMed1992

Effects of repetitive airway obstruction on O2 saturation and systemic and pulmonary arterial pressure in anesthetized dogs.

We examined the effects of multiple repetitive airway obstruction (RAO) on arterial oxygen saturation (SaO2) and pulmonary and systemic arterial pressure in eight anesthetized spontaneously breathing dogs. SaO2 was monitored at the tongue with a pulse oximeter. RAO created by an electrical valve that was attached to a tracheal cannula was alternated with seven consecutive spontaneous breaths until the nadir SaO2 (nSaO2) became constant or decreased to less than 35%. Tracheal occlusion durations of 15, 30, 45 and 60 s were chosen arbitrarily. In each animal nSaO2 decreased with every trial number in an exponential fashion, and the rate of nSaO2 fall was greater for the longer occlusion duration. In each animal the increases in pulmonary arterial pressure (PAP) and systemic arterial pressure (SAP) were inversely related to the nSaO2 values, and the relationship between nSaO2 and PAP or SAP was identical for all occlusion durations. Moreover, when the animals breathed pure oxygen and SaO2 did not decrease, there were no significant increases in the PAP and SAP at similar levels of pleural pressure (Ppl). In another six dogs, the effects of RAO on PAP and SAP were compared with those of intermittent hypoxic exposure without apnea, which was achieved by the inhalation of hypoxic gas (4 to 6% O2, 5% CO2 in N2) instead of RAO, to examine the effects of interruption of ventilation. The relationships between nSaO2 and both pressures did not differ significantly from those during RAO.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Obstruction↗

PubMed1992

YM-14673, a new thyrotropin-releasing hormone analog, augments long-term potentiation in the mossy fiber-CA3 system of guinea pig hippocampal slices.

Effects of a new thyrotropin-releasing hormone (TRH) analog, N alpha-[[(S)-4-oxo-2-azetidinyl]carbonyl]L-histidyl-L-prolinamide dihydrate (YM-14673), which improves experimentally induced memory dysfunction, on long-term potentiation (LTP) in the mossy fiber-CA3 system, were investigated using guinea pig hippocampal slices. At concentrations of 10(-7) M and 10(-6) M, YM-14673 significantly augmented LTP in a concentration dependent manner. The magnitude of effect of 10(-6) M YM-14673 was similar to that of 10(-6) M TRH. As LTP in the hippocampus is regarded as an elementary process of memory and learning, the augmenting effect of YM-14673 on LTP in the present study may contribute to this drug's ability to remedy memory dysfunction.

Animals↗

PubMed1992

[Strain differences of mice in learning of swimming behavior and effect of hemicholinium and vasopressin. Observation by a simple water maze apparatus].

In order to determine the strain differences in learning of swimming behavior and to study the influence of vasopressin or its derivatives on hemicholinium-3-induced impairment of water maze learning in mice, we designed a new apparatus using water maze which has three panels in small fish breeding water bath (L60 x W30 x H36 cm). In the first swimming, six strains of adult male mice, ICR, ddY, ddN, C3H/He, BALB/C and C57BL were subjected to learn swimming behavior twice a day for 6 d in a straight course. Only ICR, ddN, C57BL and BALB/C strain mice were chosen for the next experiment. In the second swimming, mice (ICR, ddN, C57BL, BALB/C) were swum in the water maze apparatus. Scopolamine-induced impairment of water maze learning was produced only in ICR, BALB/C mice, but not in C57BL and ddN strain, which was recovered by physostigmine. Amnesia was not obtained by intracerebroventricular injection (i.c.v.) of cycloheximide and AlCl3 in mice (ICR). Hemicholinium-induced amnesia was improved by vasopressin and desmopressin. Lysine-vasopressin and oxytocin were without affecting hemicholinium-induced amnesia. Pretreatment with a vasopressin antagonist, ([1-(beta-mercapto-beta,beta-cyclopenta-methylene propionic acid), 2-(o-methyl)tyrosine arginine]-vasopressin) resulted in a reversible effect on the improvement of hemicholinium-induced amnesia by vasopressin. Of four different strain mice, ICR mice were the most preferable to the presently used test. They were also more responsive to hemicholinium and vasopressin than the other strains. These results suggest that the simple water maze apparatus may be useful for a pre-examination of nootropics or a study of learning of swimming behavior in mice.

Animals↗

PubMed1992

[Modification of classical drug receptor mechanisms].

It is generally accepted that full and partial agonists interact with the same receptors according to the classical receptor mechanisms. We have modified the drug receptor mechanisms of M3-, alpha 1- and beta-receptors. Among the muscarinic receptors, there are two subtypes of M3-cholinoceptors, propylbenzilylcholine mustard (PrBCM)-sensitive receptors and (PrBCM)-resistant ones. Full agonists contract the guinea pig ileum through both types of cholinoceptors, while the partial agonists produce contractions through only the PrBCM-sensitive receptors. Two subtypes of alpha 1-adrenoceptors, alpha 1A and alpha 1B, were demonstrated in some arteries. Full agonists contracted the rabbit aorta through both the alpha 1A- and alpha 1B-adrenoceptors, while the partial agonists mediated contraction through only the alpha 1A-adrenoceptors. beta-Chloroethylamines (PrBCM and chloroethylclonidine) can discriminate the subtype of M3- or alpha 1-receptors in the presence of GTP. beta-Adrenoceptors have two different types of binding sites, high and low affinity sites. The competitive antagonistic effect of the partial agonist is due to their ability to compete with the full agonists for the high affinity site, while the partial agonists interact with the low affinity site to induce the beta-adrenergic effect. A regional difference in alpha 1-adrenoceptor mechanisms was discussed. The potency of norepinephrine in veins is related to alpha 1-adrenoceptor densities. In contrast, the potency of norepinephrine is linearly related to the agonist dissociation constant. This discrepancy suggests a qualitative difference between alpha 1-adrenoceptor mechanisms in the veins and arteries.

Adrenergic alpha-Agonists↗

PubMed1992

The contraction mechanisms for norepinephrine in single cells prepared from tracheal smooth muscles of guinea pig of different ages.

Single cells were prepared from guinea pig tracheal smooth muscle and used in an experiment on the contraction mechanisms for norepinephrine and a study on the change of alpha 2-adrenoceptors with age. Specific bindings of [3H]p-aminoclonidine to the single cells from the tracheal smooth muscles of 6- and 40-week-old guinea pigs were saturable and analyzed by Scatchard plot. The maximum number of [3H]p-aminoclonidine binding sites was larger in the preparation from 40-week-old guinea pigs than that from 6-week-old animals, while its dissociation constant did not change with age. The amount of prostaglandin F2 alpha released from the single cells was increased by norepinephrine, not affected by phenylephrine, and reduced by an alpha 2-antagonist such as yohimbine. The amount released by norepinephrine was significantly larger in the preparation from 6-week-old guinea pigs than that from 40-week-old animals. These results suggest that the age-related decrease in the potency of norepinephrine is due to reduction in the amount of excitable prostaglandin F2 alpha released by the drug, but not to a change in the total amount of alpha 2-adrenoceptors or the dissociation constant of the drug with respect to these adrenoceptors. Furthermore, alpha 2-adrenoceptors in the tracheal smooth muscle cell play an important role in the release of prostaglandin F2 alpha and the production of contractile responses of these muscles.

Age Factors↗

PubMed1992

Amphetamine-antagonistic property of 4-phenyltetrahydroisoquinoline: effect on noradrenaline release in spinal cord slices.

The amphetamine-related compounds methamphetamine, phenylethylamine and nomifensine increased the K(+)-evoked release of endogenous noradrenaline from rat spinal cord slices. 4-Phenyl-1,2,3,4-tetrahydroisoquinoline (4PTIQ), which alone did not affect the K(+)-evoked release of noradrenaline, inhibited the noradrenaline-releasing effects of methamphetamine, phenylethylamine and nomifensine. 4PTIQ revealed a weak noradrenaline-uptake inhibitory effect, and the effect was weaker than those of desipramine and nomifensine. These results showed that 4PTIQ is an antagonist against the amine-releasing effects of amphetamines.

Amphetamine↗

PubMed1992

Pharmacological characterization of contractile responses induced by alpha 1-agonists, norepinephrine and clonidine, by selective antagonists of their subtypes in rabbit thoracic aorta.

In the rabbit isolated thoracic aorta, WB 4101 and 5-methylurapidil dose-dependently shifted the concentration-response curves for norepinephrine to the right. Schild plots showed that the inhibition of responses for WB 4101 and 5-methylurapidil was biphasic, implying that norepinephrine acted through two receptor populations. Clonidine produced a concentration-dependent contraction in the isolated rabbit thoracic aorta. WB 4101 and 5-methylurapidil antagonized the contractions for clonidine, and the Schild plot to both antagonists against clonidine yielded a monophasic slope. Schild plots of the results obtained from the inhibition by WB 4101 and 5-methylurapidil for norepinephrine in strips pretreated with chloroethylclonidine yielded a straight line with a slope of unity. Specific binding of [3H]prazosin in the aortic membrane preparations was saturable. The Hill coefficient obtained from the inhibition curves for clonidine was significantly different from unity. Clonidine interacted with two binding sites labelled by [3H]prazosin, but the low affinity site was completely eliminated by pretreatment with 10 microM chloroethylclonidine. These results suggest that the subtype activated by norepinephrine is different from that activated by clonidine, and that norepinephrine-induced contraction through both alpha 1A- and alpha 1B-subtypes and clonidine through only the alpha 1A-subtype in the rabbit thoracic aorta.

Adrenergic alpha-Agonists↗

PubMed1992

Effects of guanosine 5'-triphosphate on the specificity of irreversible alpha 1-antagonisms by phenoxybenzamine in rabbit thoracic aorta.

Phenylephrine displacement curves for the specific binding of [3H]prazosin in the membrane fraction prepared from rabbit thoracic aorta showed high- and low-affinity sites with slope factors significantly less than unity. The irreversible alpha 1B-antagonist phenoxybenzamine shifted the binding sites to single high affinity sites with a slope factor close to unity in the presence of the metabolically stable GTP analog GTP gamma-S. These results indicate that phenoxybenzamine may have affected selectively the low affinity site to phenylephrine in the presence of GTP gamma-S.

Adenosine Triphosphate↗

PubMed1992

Identification and characterization of the alpha 2D-adrenoceptor subtype in single cells prepared from guinea pig tracheal smooth muscles.

Single cells were prepared from guinea pig tracheal smooth muscle and used in binding studies of [3H]p-aminoclonidine. Specific binding of [3H]p-aminoclonidine was saturable to a single class of receptors, with an equilibrium dissociation constant (KD) of 1.62 +/- 0.17 nM and a density (Bmax) of 6.20 +/- 0.78 x 10(4) sites/cell. Competition studies were carried out with several adrenergic antagonists. The rank order of potency was idazoxan = phentolamine > yohimbine > prazosin = corynanthine. These results suggest that the alpha 2-adrenoceptor in guinea pig tracheal smooth muscle represents a single pharmacological subtype, which is designated as alpha 2D.

Adrenergic alpha-Agonists↗