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R Satoh

Publications and source records attributed to R Satoh.

At least 37 records · Page 2Linked to original sources
PubMed1994

Ca2+/calmodulin-dependent regulation of the density of Na+ channels in embryonic chick skeletal muscle cells during their development in culture.

Regulation of the density of voltage-dependent Na+ channels (VDNC) was studied in chick myotubes during their development in culture. The density of VDNC was assessed quantitatively in terms of the maximum rate of rise (M.R.R.) of Na+ spikes. Chronic treatment of myotubes, whose density of VDNC had reached a plateau level after 6 days in culture, with the calmodulin (CaM) inhibitor W-7 caused a further increase in the density. A derivative of W-7, known as W-5, which has a lower affinity for CaM than does W-7, was without effect. A selective inhibitor of Ca2+/CaM-dependent protein kinase II (CaM-KII), namely, KN-62, also caused an increase in the density of VDNC when its effect was examined in mature myotubes. A structural analogue of KN-62, namely, KN-04, which is a much less effective inhibitor of CaM-KII, was without effect. These results suggest that density of VDNC in developing myotubes is regulated by Ca2+/CaM and CaM-KII. However, the role of CaM-KII in this regulation is not straightforward since it appears to decrease the density of VDNC in mature myotubes, but to increase their density in immature myotubes.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1993

Structural study of a cell-wall mannan of Saccharomyces kluyveri IFO 1685 strain. Presence of a branched side chain and beta-1,2-linkage.

Acetolysis of the cell-wall mannan of Saccharomyces kluyveri under mild conditions, gave fragments with 1-6 mannose residues. The structures of mannopentaose and mannohexaose were determined to be [Formula; see text] respectively, by two-dimensional homonuclear Hartmann-Hahn spectroscopy and a sequential NMR assignment method that combines 1H-13C correlated spectroscopy, relayed coherence transfer spectroscopy, 1H-detected heteronuclear multiple-bond connectivity and methylation analysis. The H1 proton chemical shift of a neighboring alpha-1,2-linked mannose unit of the 3-O-substituted structure was shifted upfield by the addition of a mannose unit to the adjacent 3-O-substituted unit by an alpha-1,6 linkage. The characteristic H1--H2-correlated cross-peak of the alpha-1,3-linked mannose unit substituted by a beta-1,2 linkage, beta 1-->2Man alpha 1-->3, in the mannan of S. kluyveri, as also found by two-dimensional homonuclear Hartmann-Hahn spectroscopy in the mannan of Candida guilliermondii, a pathogenic yeast in man.

Carbohydrate Conformation↗
PubMed1993

Transforming growth factor beta 1-induced cellular heterogeneity in the periosteum of rat parietal bones.

We examined the osteogenesis process in transforming growth factor beta 1 (TGF-beta 1)-treated neonatal and adult rats, aiming to investigate the age difference in the effect of TGF-beta 1 on mesenchymal cell differentiation. Recombinant human (rh) TGF-beta 1 (20 and 200 ng) was injected onto the outer periostea of the right side of the parietal bone of each rat once a day for 1-12 days starting at the age of either 1 day or 12 weeks. On the day after the final injection, the calvaria was excised and evaluated histologically. In the neonates, the 12-day treatment with rhTGF-beta 1 increased the number of osteoprogenitor cells, resulting in intramembranous ossification. In the adult rats, rhTGF-beta 1 induced differentiation of chondrocytes. Cartilage masses were surrounded by mesenchymal cells, which would differentiate into chondrocytes. The cartilage matrix was partially calcified, with chondrocytes buried therein. In the calcified matrix, marrow cavities containing some multinuclear osteoclasts were formed. These findings indicate that rhTGF-beta 1 stimulated the differentiation of mesenchymal cells into chondrocytes and produced the cartilaginous matrix. rhTGF-beta 1 induced intramembranous ossification of the parietal bone in neonatal rats, and it induced enchondral ossification in adults. This result suggests that the different responses of mesenchymal cells in the periosteum to rhTGF-beta 1 may depend on the age of the animals used: namely, they may reflect the respective osteogenic stages of modeling and remodeling.

Aging↗
PubMed1993

Chronological changes of MRI findings on striatal damage after acute cyanide intoxication: pathogenesis of the damage and its selectivity, and prevention for neurological sequelae: a case report.

A 31-year-old male technician in an electroplating factory, who had been suffering from the temporal lobe epilepsy for 24 years and from hypertension for 2 years, took an unknown amount of potassium cyanide apparently over the lethal dose, in an attempt to commit suicide. He was treated successfully and survived without any neurological sequelae. The electroencephalograms and the nature of the seizures were not different before and after the poisoning. The T2-weighted magnetic resonance images at 9 and 51 days after the poisoning showed bilateral elevation of signals in the caudate nuclei and the putamina. At the 143th and 286th days. T2-weighted high-resonance areas were restricted to the lateral portion of the putamina. The T1-weighted images at the 51st day showed abnormal signal elevations in both putamina, while those of 9th, 143th and 286th days were mainly normal. Selective vulnerability of the putamen and the caudate nucleus may be due to their specific structural properties of high oxygen and glucose utilization, and enzyme distribution. Both chronological changes of striatal damage and the absence of neurological sequelae in this patient suggest the possibility that anti-epileptics and a calcium antagonist played a neuroprotective role in the acute cyanide intoxication.

Adult↗
PubMed1993

Symmetrical lipomatosis of the tongue presenting as macroglossia. Report of two cases.

Symmetrical lipomatosis in the oral cavity is extremely rare. Two cases of symmetrical lipomatosis presenting as macroglossia are presented. Glossectomy was performed in order to reduce the size of the tongue and for diagnosis. Because of their multiplicity, non-encapsulation and invasiveness, the lesions were diagnosed histopathologically as symmetrical lipomatosis.

Aged↗
PubMed1993

A ring-shaped structure with a crown formed by streptolysin O on the erythrocyte membrane.

Streptolysin O (SLO) is a membrane-damaging toxin produced by most strains of group A beta-hemolytic streptococci. We performed ultrastructural analysis of SLO-derived lesions on erythrocyte membranes by examining electron micrographs of negatively stained preparations. SLO formed numerous arc- and ring-shaped structures with or without holes on membranes. Rings formed on intact cell membranes had an inner diameter of ca. 24 nm and had distinct borders of ca. 4.9 nm in width, but the diameter of rings varied from 24 to 30 nm on membranes of erythrocyte ghosts. Image analysis of electron micrographs demonstrated that each ring was composed of an inner and an outer layer. Each layer contained an array of 22 to 24 SLO molecules. On the top of the ring, we found a characteristic crown that projected from the cell membrane. The crown was separated by an electron-dense layer from the basal part of the ring that was embedded in the lipid bilayer of the erythrocyte membrane. Heights of the three parts, namely, the crown (head), the space (neck), and the basal portion (base), were ca. 3.2, 1.6, and 5.0 nm, respectively, and we postulated that these parts are the constituents of a single SLO molecule. The volumes of SLO molecules in the inner and outer layers were calculated to be 77 and 88 nm3. On the basis of a model of the structure of SLO, we propose some new details of the mechanisms of hemolysis by SLO toxin.

Animals↗
PubMed1993

[Bone mineral density of the internal auditory meatus by quantitative computed tomography].

The bone mineral density of the internal auditory meatus was investigated by means of quantitative computed tomography in 20 normal subjects (40 ears). Investigated portions of the internal auditory meatus were the porus anterior and posterior and the fundus anterior and posterior. Two other portions of the ear, the bony vestibule and lateral wall of the mastoid, were also investigated. The bone density values (calcium carbonate equivalent value) for each portion were analyzed statistically. The following results were obtained: 1) There was no significant difference between the right and left values in any portion. 2) The highest mean value was found in the fundus posterior, the lowest in the porus anterior. There was a significant difference between the values of the fundus and porus. Bone hardness generally correlates with bone density. Thus, the bone hardness of the porus of the internal auditory meatus was appraised to be lower than that of the fundus. These results suggest that this is one of the factors promoting enlargement of the internal auditory meatus in acoustic neuroma.

Adult↗
PubMed1992

Calcium channels in embryonic chick skeletal muscle cells after cultivation with calcium channel blocker.

The effects of chronic treatment with calcium channel blockers were studied on the expression of voltage-dependent calcium channels (VDCCs) in chick skeletal muscle cells developing in culture. Myotubes were treated after 2 days in culture with either 20 microM D600 or 10 microM nifedipine, and measurements were made of the maximum rate of rise (M.R.R.) of the two components of action potential, operated by T- and L-type VDCCs, respectively. Treatment with either blocker reduced the M.R.R. of the action potential component operated by the L-type VDCC throughout the culture period examined. The M.R.R. of the T-type VDCC component, on the other hand, was unaffected by either treatment. The reduction in the M.R.R. of the L-type component in blocker-treated cells is thought to be due to the down-regulation of the expression of L-type VDCC. Thus, it appears that the expression of L-type VDCC in the chick skeletal muscle cells can be regulated by a function of L-type VDCC, which mediate the entry of Ca2+ into the cells. The physiological significance of the L-type VDCC, which expressed prominently early in the development of skeletal muscle cells, for the differentiation of excitability is discussed.

Action Potentials↗
PubMed1992

Chronic treatment with D600 enhances development of sodium channels in cultured chick skeletal muscle cells.

We have studied the long-term effects of D600, a blocker of L-type voltage-dependent Ca channels (VDCC), on the development of voltage-dependent Na channels (VDNC) that are sensitive to tetrodotoxin (TTX), by electrophysiological measurements of the maximum rate of rise of the TTX-sensitive Na spike in cultured chick skeletal muscle cells. Chronic treatment with D600 (2-20 microM) caused a dose-dependent increase in the density of VDNC. The density of VDNC was increased by 150-250% when D600 was added to the cultures at 20 microM from the second day of culture onward. Co-treatment with an inhibitor of the transcription of RNA from DNA, alpha-amanitin, or with cycloheximide, an inhibitor of protein synthesis, prevented the up-regulation by D600. Nifedipine, a different type of blocker of L-type VDCC, was also effective in increasing the density of VDNC, and BAY K 8644, an agonist of L-type VDCC, had the opposite effect. It is suggested that the effect of D600 was mediated via a mechanism specific for L-type VDCC that involves regulation of cytosolic levels of Ca2+ and protein synthesis de novo.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1992

[Difference between horizontal enlargement and vertical enlargement of the internal auditory meatus in acoustic neuroma].

Twenty-one patients with acoustic neuroma were investigated. The vertical diameter of the internal auditory meatus was measured by polytomography, the horizontal by target imaging CT. The ratio of the abnormal side to the normal side was calculated in each dimension. Two dimensional ratios were compared with each other in order to investigate the difference between horizontal and vertical enlargement of the internal auditory meatus. The results were as follows: 1) Horizontal enlargement of the internal auditory meatus was greater than that of the vertical one in 15 cases (75%). Vertical enlargement was greater in 6 cases but the difference between the two dimensions was not significant. 2) With horizontal enlargement, the posterior wall of the internal auditory meatus was more extended or destroyed than that of anterior wall. 3) With enlargement of the posterior wall, the bony eminence forming the inner side of the porus was predominantly extended or destroyed in every case.

Adolescent↗
PubMed1992

The bradykinin antagonist Hoe 140 inhibits carrageenan- and thermically induced paw oedema in rats.

The new and highly potent B2 bradykinin (BK) antagonist Hoe 140 was tested for its ability to inhibit oedema of rat paws induced by scalding and carrageenan. The data show that Hoe 140 inhibits scalding and carrageenan oedema for more than four and six hours, respectively. Based on its potency against actions of endogenously generated kinins Hoe 140 is appropriate to investigate the role of kinins in human inflammatory diseases.

Animals↗
PubMed1991

Pharmacological properties of two types of calcium channel in embryonic chick skeletal muscle cells in culture.

We have studied the effects of organic and inorganic Ca channel blockers on the two-component action potentials (low- and high-threshold components) in cultured chick skeletal muscle cells, which are generated by the T- and L-type voltage-dependent Ca channels (VDCCs), respectively. Nifedipine and D600 effectively blocked the high-threshold component of the action potential, whereas omega-conotoxin and phenytoin had no effect on this component. By contrast, the low-threshold component was insensitive to all of these organic Ca channel blockers. Blocking effects of polyvalent cations were observed with the following rank order of relative potency (mean apparent dissociation constant in microM): La3+ (14.7) greater than Ni2+ (20.7) greater than Cd2+ (51.2) greater than Co2+ (912) for the low-threshold component, and Cd2+ (0.7) greater than La3+ (29.2) greater than Co2+ (431) greater than Ni2+ (1241) for the high-threshold component. Taken together, these findings suggest that the pharmacological properties of the T- and L-type VDCCs in cultured chick skeletal muscle cells may differ from those in other preparations.

Action Potentials↗
PubMed1991

[A case of beriberi heart--with special reference to the rapid effect of fursultiamine on hemodynamics].

A 33-year-old man was admitted to Kushiro City General Hospital on February 27, 1989, because of palpitation, shortness of breath and anasarca. Eight months previously he had noted the onset of pretibial edema, which had progressed to anasarca. He had had a meal only once a day for nine months. Physical examination revealed a blood pressure of 114/46 mmHg and pulse rate of 80/min. The 3rd sound was audible. No rales in the chest and no hepatosplenomegaly were noted. Ascites, pretibial edema and anasarca were present. Vibration sensation was diminished, and the deep tendon reflexes were absent in the legs. The blood thiamine level on the 4th day of hospitalization decreased to 2.9 micrograms/dl. The red cell transketolase activity and TPP effect on the 10th hospital day were 0.76 IU/gHb and 11%, respectively. A chest roentogenogram showed pulmonary congestion and cardiomegaly (CTR 61.3%). The electrocardiogram showed non-specific T wave changes. On the echocardiogram, remarkable pericardial effusion and diffuse hypertrophy of the left ventricular wall were observed. In addition, the left ventricular wall motion showed a hyperkinetic state. On the basis of these findings, the diagnosis of beriberi heart was made. The hemodynamic study performed on the 10th hospital day showed a remarkable high cardiac output (CO) of 10.7 l/min and an extremely reduced total peripheral resistance (TPR) of 352 dynes.sec.cm-5. 15 min after intravenous administration of Fursultiamine 100 mg, CO decreased to 7.24 l/min and TPR increased to 848 dynes.sec.cm-5. Following the administration of Fursultiamine 75 mg, po/day, his symptoms and abnormal findings of clinical examination data rapidly improved.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Acute toxicity study of cefpirome sulfate in mice and rats].

Acute toxicity of cefpirome sulfate (CPR) was examined in 6-week-old mice and rats and immature (5-day-old) rats. The LD50 values of CPR (mg/kg) were as follows: (1) mice: intravenous, 2420 (95% confidence limits, 2122-2758) for males and 2400 (2181-2640) for females; intraperitoneal, 3850 (3407-4351) for males and 4200 (3889-4536) for females; and oral, 16200 (14781-17755) for males and 18500 (17290-19795) for females. (2) 6-week-old rats: intravenous, 1900 (1784-2023) for males and 2080 (1953-2215) for females; intraperitoneal, 6550 (6179-6943) for males and 5800 (5311-6334) for females; subcutaneous, more than 10000 for both sexes; and oral, more than 8000 for both sexes. (3) 5-day-old rats: subcutaneous, between 1750 and 2500 for males and 2080 (1651-2621) for females. Major changes in general health conditions observed in 6-week-old mice and rats were decreased spontaneous activity, lying prone, tremor, respiratory changes (slow or deep respiration, gasping), clonic or clonic-tonic convulsions. In the 6-week-old rats dosed subcutaneously, vocalization, writhing and cutaneous changes at the injection site (dark reddening or blackening, swelling, exfoliation, depilation, induration) were also observed. In the 5-day-old rats dosed subcutaneously, the changes noted were slow respiration, writhing, cyanosis, and dark reddening and swelling of the skin at the injection site. After administration, transient depression of body weight gain or loss of body weight was observed in the mice and rats except the rats dosed orally. These changes disappeared at 7 days after administration at latest, and all surviving animals showed favorable body weight gain thereafter. Necropsies revealed hemorrhage under meninges in the brain in many of the mice and rats which died. Other findings included subcutaneous changes at the injection site in the 6-week-old and 5-day-old rats dosed subcutaneously (dark reddening, retention of dark red fluid, retention of red, white or dark red gelatinous material) and changes in the peritoneal cavity in the 6-week-old rats dosed intraperitoneally (red or dark red spots on the serous membrane, reddening of adipose tissues).

Animals↗
PubMed1990

[Antigenicity study of cefpirome sulfate].

Immunological properties of cefpirome sulfate (CPR) were examined. The immunogenicity and challenging ability of CPR were examined in guinea pigs by active systemic anaphylaxis (ASA) and homologous 4-hr passive cutaneous anaphylaxis (PCA) tests. The animals given CPR alone intraperitoneally for sensitization and their sera were negative for ASA or PCA reactions, like the results with reference substances, ceftazidime (CAZ) and cephalothin sodium (CET). When each antibiotic plus Freund's complete adjuvant (FCA) was used for sensitization, ASA reactions were observed with CPR, cephaloridine (CER), CET, and cefazolin sodium (CEZ), and PCA reactions, with CPR and CET. CPR had the ability to challenge the ASA and PCA reactions. CER and CET also showed the ability to challenge ASA or PCA reactions, though at low incidences. The cross-reactivity of CPR with commercially available antibiotics was examined by heterologous PCA test and by passive hemagglutination test and its inhibition test. The antiserum used was from rabbits immunized with each antibiotic-ovalbumin conjugate plus FCA, and the antigen was each antibiotic-bovine serum albumin conjugate. CPR cross-reacted markedly with cefotaxime sodium (CTX) having the same side chain at position 7 and showed weak, unidirectional reactions with CAZ and CET. In the in vitro direct Coombs test, the positive reactions noted with CPR were stronger than those with latamoxef sodium, equal to those with CEZ and slighter than those with CTX, CET and benzylpenicillin potassium. In conclusion, in the safety evaluation of CPR, its antigenic potential may not be a problem, like the cases of other antibiotics.

Anaphylaxis↗
PubMed1990

[Local irritancy study of cefpirome sulfate].

As a series of safety studies of cefpirome sulfate (CPR), its local irritancy was examined in rabbits after the following treatments: intracutaneous injection (single), application into the conjunctival sac of the eye (single), intramuscular injection (single, 7-day repeated), and intravenous injection (8-day repeated). In addition, the hemolysis test was carried out with human blood. When CPR was injected intracutaneously at a high concentration of 20%, its irritating effects were only equal to or slightly stronger than those of distilled water for injection and Na2SO4 solution. The same concentration of the compound applied into the conjunctival sac had little irritancy to the eye. In the single intramuscular administration experiment, muscular changes caused by 10% CPR were comparable to those by 0.75% acetic acid, slightly severer than those by physiological saline, and slighter than those by 6% acetic acid at 2 days after administration, but at 7 days, the changes were apparently slighter than those by 0.75% acetic acid. CPR is classified under Grade 3 according to the draft guidelines for local tolerability studies issued by the Ministry of Health and Welfare of Japan. The repeated intramuscular administration experiment showed the following results. Muscular changes caused by 10% CPR were comparable to those by physiological saline and slighter than those by 0.75% acetic acid, 5% cefotetan (CTT) and 20% cephalothin sodium (CET) at 2 days after the last administration. At 7 days, the changes were slightly severer than those by physiological saline, but slighter than those by the other control solutions. Microscopically, a tendency toward recovery was marked. In the vascular irritancy experiment, the 10% CPR group showed thrombus macroscopically on and after day 5 of dosing. Microscopy at the end of the 8-day administration period revealed thrombus and organized thrombus. In the 20% CET group, thrombogenesis was slighter than that in the 10% CPR group, while perivascular changes were severer. The changes caused by 5% CTT (thrombogenesis, perivascular changes) were somewhat severer than those by 10% CPR. In the hemolysis test, 10% CPR solution applied to fresh blood from adult men caused to hemolysis when determined by the macroscopic or spectrophotometric method.

Animals↗
PubMed1990

Increases in alpha-but not beta-adrenoceptors in hypertrophied non-infarcted cardiac muscles from rats with chronic myocardial infarction.

The alteration in adrenoceptors in the hypertrophied right ventricle of the rats with myocardial infarction (Ml) was examined. The density of alpha-1-adrenoceptors increased in four and twelve week old Ml rats but not in one week old Ml rats. The beta-adrenoceptors did not significantly change. It is probable that the increased density of alpha-adrenoceptors may be one of the causes for the increased responsiveness to the alpha-adrenergic agonist in the hypertrophied cardiac muscles of Ml rats.

Animals↗