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Biomedical subjects

H Satoh

Publications and source records attributed to H Satoh.

At least 217 records · Page 12Linked to original sources
PubMed1999

Matrix interferences in the analysis of digested biological tissues with inductively coupled plasma-mass spectrometry.

To investigate the physiological roles or toxicity of trace or toxic elements, multielement analysis of limited quantities of samples in the biological tissues is required. Inductively coupled plasma mass spectrometry (ICP-MS) suits this requirement, but spectral and nonspectral interferences are inevitable. We examined correction methods for the nonspectral interferences by analyzing signals of 21 elements in various concentrations of HNO3 as well as five major elements (Na, K, P, Ca, and Cl). Using internal standards, the interferences caused by the major elements were corrected, but the interferences caused by HNO3 were impossible to correct for elements with high ionization potentials. The analytical results using the standard addition method on 14 elements in standard reference materials and fresh brain tissues confirmed the accuracy of this method. Thus, we concluded that the standard addition method is useful to correct for the nonspectral interferences.

Artifacts↗
PubMed1999

Organization, structure, and evolution of the nonadult rat beta-globin gene cluster.

The beta-globin gene cluster of Wistar rat was extensively cloned and the embryonic genes were mapped and sequenced. Four overlapping lambda Dash recombinant clones cover about 31 kb and contain four nonadult beta-globin genes, 5'-epsilon1-gamma1-gamma2-psigamma3-3'. The epsilon1 and gamma2 are active genes, since their protein products were detected in the fetal stage of the rat (Iwahara et al., J Biochem 119:360-366, 1996). The gamma1 locus might be a pseudogene, since the ATA box in the promoter region is mutated to GTA; however, no other defect is observed. The psigamma3 locus is a truncated pseudogene because a 19-base deletion, which causes a shift of the reading frame, is observed between the second nucleotide of the putative codon 68 and codon 76. A sequence comparison suggests that the psigamma3 might be produced by a gene conversion event of the proto-gamma-globin gene set. Possible histories of the evolution of rat nonadult beta-globin genes are discussed.

Amino Acid Sequence↗
PubMed1999

Capture of a genomic HMG domain sequence by the En/Spm-related transposable element Tpn1 in the Japanese morning glory.

The non-autonomous transposable element Tpn1 from the Japanese morning glory is an En/Spm-related DNA element found in the second intron of the DFR-B gene for flower pigmentation in the mutable line flecked, which shows variegation for flower color. It carries a genomic DNA segment containing at least four exon sequences encoding part of a HMG-box sequence. Spliced hybrid transcripts containing the DFR-B exon(s) and the HMG exons in Tpn1 were detected in the flower buds of the flecked line, and they were polyadenylated within Tpn1. Thus, Tpn1 can be regarded as a specialized transducing transposon carrying a part of the genomic sequence for a HMG box. The possible implications of the finding for evolution are discussed.

Amino Acid Sequence↗
PubMed1999

Adenoma arising from the cystic duct and extending to the confluence of the extrahepatic biliary tract.

We describe a rare case of adenoma with a few foci of severe atypia arising from the cystic duct in a 68-year-old woman, initially diagnosed by the presence of intracholecystic tumefactive sludge on abdominal ultrasonography. Endoscopic retrograde cholangiography (ERC) disclosed a tuberous filling defect at the orifice of the cystic duct. Pathology examination of the biopsied specimen obtained from ERC disclosed not a cancerous but an adenomatous lesion. Macroscopically, the resected specimen showed a superficially spreading and shallowly elevated lesion extending from the cystic duct to the common bile duct. Although a few sporadic foci of severe atypia were observed, microscopy did not reveal any cancer findings, but confirmed the tumorous lesion as benign adenoma, showing mild-to-moderate atypia. Postoperative immunohistochemistry revealed no expression of p53 protein. We briefly refer to the rarity of adenoma in the biliary tract and discuss the difficulty of differential diagnosis of neoplastic lesions in the extrahepatic biliary tract.

Aged↗
PubMed1999

Dissecting aneurysm of basilar artery presenting with recurrent subarachnoid hemorrhage.

Spontaneous basilar dissecting aneurysms secondary to subarachnoid hemorrhage are rare, usually presenting with ischemia rather than a subarachnoid hemorrhage (SAH). A 63-year-old man who had SAH repeatedly from a ruptured basilar dissecting aneurysm was treated with endovascular occlusion of the unilateral vertebral artery. Postoperative angiograms 1 month after the procedure showed complete obliteration of the aneurysm. The clinical follow-up at 20 months showed no evidence of recurrent hemorrhage.

Aortic Dissection↗
PubMed1999

Effect of CABG on coronary flow reserve in atresia of the left coronary ostium.

We evaluated the change of coronary flow reserve using a Doppler guidewire before and after coronary artery bypass grafting to assess the coronary hemodynamic effect of surgical revascularization in a 13-year-old boy with congenital atresia of the left coronary ostium, which is one of the rarest of the congenital coronary anomalies. Coronary flow reserve in the right coronary artery and left anterior descending artery increased significantly after coronary revascularization, and a microvascular bed developed in the left anterior descending artery.

Adolescent↗
PubMed1999

Primary structure and function of superoxide dismutase from the ascidian Halocynthia roretzi.

A protein with a molecular weight of 17K, immunoreactive with the S-1B2 antibody, has been isolated from hemocytes of Halocynthia roretzi. Its amino acid sequence has been determined by sequential Edman degradation analysis of peptide fragments derived from proteolytic fragmentation. The 17K protein is a single chain protein consisting of 151 amino acids with an acylated N-terminal serine. A comparison of the amino acid sequence of H. roretzi 17K protein with those of other proteins reveals that the 17K protein is Cu,Zn-SOD. The protein was found to have a KCN-inhibited SOD activity. Cu,Zn-SOD has been purified from H. roretzi plasma. The molecular weight is 17K and the activity is inhibited with KCN and diethyldithiocarbamate. It has been demonstrated that it can enhance phagocytosis by H. roretzi hemocytes. Thus, plasma Cu,Zn-SOD plays a role in H. roretzi as a defense molecule.

Amino Acid Sequence↗
PubMed1999

Possible involvement of [Ca2+]i level in the modulation of the current-voltage relationship for the fast Na+ current in late embryonic chick cardiomyocytes.

Modulation by intracellular Ca2+ concentration ([Ca2+]i) of the reversal potential for the fast Na+ current (INa) in 17-day-old embryonic chick ventricular cardiomyocytes was examined using a whole-cell voltage-clamp technique. Experiments were performed at room temperature (22 degrees C). Test pulses were applied between -60 to +50 mV from a holding potential of -90 mV. The INa was TTX-sensitive, and the reversal potential was +47.3+/-2.2 mV (n = 20) at pCa 10. Neither pCa 7 or pCa 10 caused any effect on the peak amplitudes of INa, but the reversal potential at pCa 7 shifted in the hyperpolarizing direction by 10.5+/-2.8 mV (n = 10, p < 0.05), as compared with that at pCa 10. The hyperpolarizing shift was also observed by application of taurine, and behaved in a concentration-dependent manner; by 10.4+/-2.3 mV (n = 8, p < 0.05) at 10 mM, and by 12.1+/-2.3 mV (n = 8, p < 0.05) at 20 mM. Even when taurine at low concentration (5 mM) enhanced INa, the similar shift of the reversal potential occurred. These results suggest that the shift of reversal potential of the INa in embryonic chick cells would be involved with somewhat cellular mechanism dependent on [Ca2+]i, which may play an important role for cardiac functions of the embryonic cells.

Animals↗
PubMed1999

Pharmacological actions of monovalent ionophores on spontaneously beating rabbit sino-atrial nodal cells.

The effects of sodium (monensin) and potassium (nigericin and lonomycin A) ionophores on the spontaneous activity in rabbit sino-atrial (SA) nodal cells were investigated using microelectrode and whole-cell voltage-clamp techniques. In the multicellular preparations, the ionophores produced a negative chronotropic effect in a concentration-dependent manner, and at 3x10(-5) M significantly decreased the amplitude and duration of action potentials and enhanced the maximum rate of depolarization. The ionophores elicited dysrhythmias and then a sinus arrest often occurred. These responses were reversible. In whole-cell clamp experiments, monensin enhanced the L-type Ca2+ current (ICa), whereas lonomycin A and nigericin inhibited ICa. The fast component of the inactivation phase for ICa was decreased by the ionophores, but the slow component was unaffected. The activation and inactivation kinetics (d infinity and f infinity) were not altered. The ionophores did not affect the hyperpolarization-activated inward current. Monensin inhibited the delayed rectifier K+ current (I(K)), but lonomycin A and nigericin increased I(K). Its activation kinetics shifted in the depolarizing direction. The effects on the ionic currents were irreversible. Monensin (30 microM) increased cellular Ca2+ concentration ([Ca2+]i), using Ca2+ -sensitive fluorescent dye (fura-2). These results indicate that the monovalent ionophores depress the action potentials and produce a negative chronotropic effect due to direct and indirect modulations of the ionic currents and the [Ca2+]i level in rabbit SA nodal cells.

Action Potentials↗
PubMed1999

All-trans retinoic acid enhances gap junctional intercellular communication among renal epithelial cells in vitro treated with renal carcinogens.

Epidemiological and clinical studies imply that retinoids have a chemopreventative action against cancer and can suppress the growth of cancer cells. The regulation of connexin (Cx) expression by retinoids varies among tissues and organs. In this study, we investigated whether all-trans retinoic acid (ATRA) upregulates gap junctional intercellular communication (GJIC) in renal epithelial cells exposed to renal carcinogens. Madin Darby canine kidney (MDCK) cells were incubated with ATRA for 3 days, then briefly exposed to 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or renal carcinogens potassium bromate (KBrO3) and dimethylnitrosamine (DMN). ATRA increased the expression of connexin 43 mRNA and protein without affecting Cx 43 phosphorylation and prevented inadequate Cx 43 localisation caused by TPA/KBrO3 or DMN. Consequently, ATRA prevented the disruption of GJIC in MDCK cells. These data suggest that ATRA enhanced GJIC by upregulating Cx 43 expression and that ATRA might be useful for prevention of renal cell carcinoma.

Blotting, Western↗
PubMed1999

A single cell model of myocardial reperfusion injury: changes in intracellular Na+ and Ca2+ concentrations in guinea pig ventricular myocytes.

To investigate the contribution of the changes in intracellular Na+ and Ca2+ concentrations ([Na+]i and [Ca2+]i) to myocardial reperfusion injury, we made an ischemia/reperfusion model in intact guinea pig myocytes. Myocardial ischemia was simulated by the perfusion of metabolic inhibitors (3.3 mM amobarbital and 5 microM carbonyl cyanide m-chlorophenylhydrazone) with pH 6.6 and reperfusion was achieved by the washout of them with pH 7.4. [Na+]i increased from 7.9 +/- 2.0 to 14.0 +/- 3.4 mM (means +/- S.E., p < 0.01 ) during 7.5 min of simulated ischemia (SI) and increased further to 18.8 +/- 3.0 mM at 7.5 min after reperfusion. [Ca2+]i, expressed as the ratio of fluo 3 fluorescence intensity, increased to 133 +/- 8% (p < 0.01) during SI and gradually returned to the control level after reperfusion. Intracellular pH decreased from 7.53 +/- 0.04 to 6.31 +/- 0.04 (p < 0.01) and recovered quickly after reperfusion. Reperfusion with the acidic solution or the continuous perfusion of hexamethylene amiloride (2 microM) prevented the reperfusion-induced increase in [Na+]i. When the duration of SI was prolonged to 15 min, the cell response after reperfusion varied, 16 of 37 cells kept quiescent, 21 cells showed spontaneous Ca2+ waves, and 4 cells out of these 21 cells became hypercontracted. In quiescent cells, both [Na+]i and [Ca2+]i decreased immediately after reperfusion. In cells with Ca2+ waves, [Na+]i transiently increased further at the early phase of reperfusion, while [Ca2+]i declined. In hypercontracted cells, [Na+]i increased as much as in 'Ca2+ wave' cells, but [Ca2+]i increased extensively and both ion concentrations continued to increase. Reperfusion with the Ca2+-free solution prevented both the [Ca2+]i increase and morphological change. In the presence of ryanodine (10 microM), the increase in [Ca2+]i after reperfusion was augmented and some cells became hypercontracted. We concluded that (1) Na+/H+ exchange is active both during SI and reperfusion, resulting in the additional [Na+]i elevation on reperfusion, (2) the [Na+]i level after reperfusion and the following Ca2+ influx via Na+/Ca2+ exchange are crucial for reperfusion cell injury, and (3) the Ca2+ buffering capacity of sarcoplasmic reticulum would also contribute to the Ca2+ regulation and cell injury after reperfusion.

Amiloride↗
PubMed1999

Taurine modulates I(Kr) but I(Ks) in guinea-pig ventricular cardiomyocytes.

1. Effects of taurine on the delayed rectifier K+ current (I(K)) in isolated guinea-pig ventricular cardiomyocytes were examined at different intracellular Ca2+ concentration ([Ca2+]i), using whole-cell voltage and current clamp techniques. Experiments were performed at 36 degrees C. 2. Addition of taurine (10-20 mM) decreased the action potential duration (APD) at pCa 8, but increased the APD at pCa 6. Taurine (20 mM) enhanced I(K) at 70 mV by 22.4 +/- 3.1% (n = 6, P < 0.01) at pCa 8, whereas taurine inhibited the I(K) by 27.1 +/- 2.7% (n = 6, P < 0.01) at pCa 6. These responses behaved in a concentration-dependent manner. 3. The I(K) is composed of the rapid and slow components (I(Kr) and I(Ks)). When [Ca2+]i was pCa 6, taurine at 20 mM reduced the tail current of I(Kr) at 70 mV by 16.5 +/- 2.7% (n = 5, P < 0.05) and that of I(Ks) at 70 mV by 27.1 +/- 2.8% (n = 6, P < 0.01). In contrast, at pCa 8, the tail currents of I(Kr) and I(Ks) at 70 mV were enhanced by 13.4 +/- 3.2% (n = 7, P < 0.05) and by 22.4 +/- 3.1% (n = 7, P < 0.01), respectively. The voltages of half-maximum activation (V1/2) for I(Kr) and I(Ks) were not modified by taurine. 4. Addition of E-4031 (5 microM) to taurine had a complete blockade of the tail current of I(Kr), but not I(Ks). The remained tail current (I(Ks)) in the presence of E-4031 (5 microM) was not affected by taurine (20 mM), but was blocked by 293B (30 microM). 5. These results indicate that taurine modulates I(Kr) but not I(Ks), depending on [Ca2+]i, resulting in regulation of the APD.

Action Potentials↗
PubMed1999

Poorer nutritional status of the older-generation in a Japanese farming village, as related to fewer types of food consumed.

This study was carried out to determine whether the most recent nutritional improvements in Japanese farming villages were due to improvement in the diet of the young only or across all ages. Food duplicates for 24 h were collected. The number of food items and the adequacy of each nutrient level were compared between subgroups, by age of cooking and those eating meals. The older-generation used and ate fewer food items resulting in poorer nutrition. The most recent improvement in nutrition in the farming villages of Japan was found mainly to affect the younger-generation with the older-generations being more poorly nourished.

Adult↗
PubMed1999

Lesion mimic mutants of rice with alterations in early signaling events of defense.

We screened 93 lesion mimic mutants of rice for resistance to the blast fungus, Magnaporthe grisea, and found eight mutants that exhibited significant resistance to the fungus. We called these mutants cdr (cell death and resistance) and further analyzed three of them. Two mutations, cdr1 and cdr2, were recessive and one, Cdr3, was dominant. Many small brownish lesions developed over the entire leaf of the mutants 20-50 days after sowing. TUNEL staining revealed that DNA fragmentation occurred in leaf blade cells of the homozygous Cdr3 mutants. Autofluorescence and callose deposition were visible in leaf cells of these three mutants. Activation of two defense-related genes, PBZ1 and PR1, was observed in the leaves of the mutants; high expression of PBZ1 was correlated with the lesion formation in the three mutants, whereas PR1 was constitutively expressed in the cdr2 and Cdr3 mutants irrespective of the lesion formation. Levels of momilactone A, a major phytoalexin of rice, in these mutants were increased approximately 100-400-fold relative to the wild-type levels. Suspension-cultured cells of the cdr1 and cdr2 but not Cdr3 produced higher levels of H2O2 than the wild type when treated with calyculin A, an inhibitor of protein phosphatase 1. These results suggest that biochemical lesions of cdr1 and cdr2 lie in the early signaling steps leading to activation of the NADPH oxidase and that type-1 protein phosphatase is operative in protein dephosphorylation involved in NADPH oxidase activation.

DNA Fragmentation↗
PubMed1999

Analysis of myelodysplastic syndrome clones arising after multiple myeloma: a case study by correlative interphase cytogenetic analysis.

BACKGROUND: A patient with multiple myeloma developed myelodysplastic syndrome (MDS). Chromosomal analysis performed after the development of MDS revealed monosomy of chromosome 9 in all the meta-phases. We wished to identify the extent of the clone with the chromosomal abnormality originating from MDS clone. METHODS: A correlative interphase study by fluorescence in situ hybridization (FISH) was performed and we determined whether each lineage of cells obtained the molecular mark. The chromosome 9 classic alpha satellite region DNA was used as a probe for the FISH analysis in smear specimens stained with Wright-Giemsa stain. RESULTS: Erythroblasts, granulocytes and myelocytes had only one signal, whereas myeloma cells showed two to four signals. CONCLUSION: This study visualized the spectrum of MDS clone. The results suggest that the origin of MDS is different from that of multiple myeloma, at least in this case.

Chromosomes, Human, Pair 9↗
PubMed1999

Recognition control of the nucleic acid model through conformational switching of nucleobase induced by borate ester formation of cis-2',3'-diol.

A novel nucleic acid model that possessed 5'-amino-5'-deoxyuridine at alpha- and gamma-position of L-glutamic acid through amide linkage using 5'-amino group was synthesized and the conformation and the hybridization properties were studied. The complex of alpha-PRNA with complementary DNA/RNA was more stable than the corresponding natural duplex in the absence of borate. Its recognition ability was however lost when borax was added to the solution.

Borates↗