Biomedical subjects

H Satoh

Publications and source records attributed to H Satoh.

At least 487 records · Page 27Linked to original sources

PubMed1994

The rat and human hemopexin genes contain an identical interleukin-6 response element that is not a target of CAAT enhancer-binding protein isoforms.

Hemopexin (Hx) is an abundant acute-phase protein (APP) that binds heme with high affinity. In rat hepatic cells, the transcription rate of the Hx gene is increased by interleukin (IL)-1 and IL-6. To investigate the cis-acting regulatory elements (REs) responsive to these hormones, chloramphenicol acetyltransferase constructs of rat and human Hx gene sequences were tested in transiently transfected hepatoma cells. An IL-6-RE was identified in the promoter of both rat and human Hx genes, the function of which was dependent on the core sequence (CCGGGAA) common in other APP genes. The previously characterized Hx A element mediated a relatively minor cytokine response as compared with the Hx IL-6-RE. The human Hx A element, in contrast to the rat and human Hx IL-6-REs, was strongly trans-activated by cotransfected CAAT enhancer-binding proteins (C/EBP)-beta and -delta. The rat gene homolog of the human Hx A element was inactive as a cytokine RE and was minimally trans-activated by C/EBP isoforms. Results of electrophoretic mobility shift assays indicated that the Hx IL-6-RE is a binding site for the IL-6-inducible nuclear protein IL-6 RE-BP, which also binds to the conserved IL-6-REs of other APP genes and is distinct from C/EBP beta.

Animals↗

PubMed1994

Identification of a liver preference enhancer element of the rat hemopexin gene and its interaction with nuclear factors.

Transcription of hemopexin (Hx) occurs predominantly in the liver. To investigate the contribution of the cis-acting enhancer element to the hepatocyte preferential expression, we performed chloramphenicol acetyl-transferase (CAT) assays in HepG2 cells. A strong enhancer element was identified by successive truncation to reside in the region -157/-104 from the cap site. The Hx region -145/-125 interacts with rat liver nuclear proteins, as shown by standard DNA-protein binding assays. The nucleotide sequence -141AGACTTTGACCT-130 includes, in reverse orientation, a direct repeat of the imperfect AGGTCA sequence, one of the recognition motifs of the steroid-thyroid hormone receptor superfamily. That this AGGTCA repeat is an enhancer core of the Hx element was affirmed by mutational analyses. In electrophoretic mobility shift assays, oligonucleotides, corresponding to binding regions of chicken ovalbumin upstream promoter transcription factor (COUP-TF) and apolipoprotein AI regulatory protein 1 (ARP-1) but not of hepatocyte nuclear factor-4 (HNF-4), competed with the Hx element for binding sites. Co-transfection analyses indicated that HNF-4 does not affect CAT expression whereas ARP-1 and COUP-TF repress it. Antibody supershift analyses suggested that HNF-4 and COUP-TF may not be major factors binding to the Hx element.

Animals↗

PubMed1994

Unusual generation of hydroxyl radicals in hepatic copper-metallothionein of LEC (Long-Evans cinnamon) rats in the presence of hydrogen peroxide.

A mutant strain of LEC rats (Long-Evans rats with a cinnamon-like coat color) develop spontaneous hepatic injury associated with severe jaundice about 4 months after birth. Recently, we obtained evidence which shows an unusual accumulation of copper (Cu) in the liver of LEC rats, followed by the finding of copper-metallothionein (Cu-MT) induction. To know the mechanism for the development of hepatitis in LEC rats, in relation to induced Cu-MT, we examined whether the generation of active oxygen species is observed. When the Cu-MT was treated with H2O2, which is formed by dismutation of superoxide anion radicals or NADPH oxidases in living systems, strong ESR signals due to Cu(II) state appeared when measured at 77K. On the same system, ESR signals due to the spin trapped hydroxyl radicals were observed at room temperature when DMPO (5,5-dimethyl-pyrroline-1-oxide) was used as a spin-trapping agent. The present results suggested that Cu-MT of LEC rat has an important pathogenic role by generating hydroxyl radicals, when hydrogen peroxide is produced in cells or tissues.

Animals↗

PubMed1994

Expression of the c-kit ligand and interleukin 6 genes in mouse bone marrow stromal cell lines.

The expression of c-kit ligand and interleukin 6 (IL-6) genes in mouse bone marrow-derived stromal cell lines was examined using quantitative polymerase chain reaction (PCR) analysis based on the design of an internal DNA control. The stromal cells studied included the 14F1.1 endothelial-adipocytes that support long-term hemopoiesis and two additional cell lines (MBA-1, MBA-13) which do not have this function. All the cell lines expressed c-kit ligand gene constitutively, and this expression was not increased by lectins. On the other hand, the expression of the IL-6 gene was markedly induced in all the lines by lipopolysaccharide (LPS) and by phorbol 12-myristate 13 acetate (PMA). The constitutive expression of c-kit ligand in 14F1.1 cells was the lowest among the three cell lines studied and could be increased by stimulation with IL-4. Thus, we observed some quantitative differences among the cell lines in their expression of cytokine genes. However, the unique capacity of 14F1.1 cells to support in vitro hemopoiesis cannot thus far be explained solely on the basis of the ability of these cells to secrete cytokines which are not produced by other stromal cell lines. c-kit ligand may be necessary, but its presence alone is not sufficient for 14F1.1 cells to support prolonged hemopoiesis.

Adipose Tissue↗

PubMed1994

Cardioprotective actions of taurine against intracellular and extracellular calcium-induced effects.

The effects of taurine were modulated by the [Ca2+]i or/and [Ca2+]o levels, consistent with recent reports (10, 28, 31). Taurine may directly and indirectly regulate the [Ca2+]i level by modulating Ca2+ channels (dependent on [Ca2+]i/[Ca2+]o) and Na+ channel (via Na(+)-Ca2+ exchange). Thus, taurine antagonizes Ca2+ ([Ca2+]o or [Ca2+]i)-induced cardiac functions. The data for the effects of taurine on the ionic currents and action potentials (automaticity) are summarized in Tables 1 and 2. These results indicate that taurine exerts potent cardioprotective actions under the conditions induced by low Ca2+ level as well as by calcium overload. In conclusion, the effects of taurine are complex, there being a number of actions on cardiac muscle which may show the possible therapeutic use of this sulfur amino acid.

Action Potentials↗

PubMed1994

MRI of pituitary adenomas: the position of the normal pituitary gland.

The position of the normal pituitary gland, assessed using gadolinium - enhanced MRI was compared with the position found at surgery for pituitary adenoma in 25 patients. The tumours were five microadenomas and 20 macroadenomas. Using T1-weighted imaging, the anterior lobe could be differentiated on the sagittal image in five patients (20%) and on the coronal image in four (16%). The high intensity of the posterior lobe could be differentiated using T1-weighted sagittal imaging in 13 patients (52%). The normal pituitary gland, which enhanced more strongly than tumour, could be differentiated using Gd-DTPA-enhanced MRI on the sagittal images in 22 cases (88%) and on the coronal image in 17 (68%). In seven patients, the normal pituitary gland surrounded the tumour; it was displaced superiorly in 14 cases and superioposterorly in two but in no case was it displaced anteriorly or downwards.

Adenoma↗

PubMed1994

Displacement of the normal pituitary gland by sellar and juxtasellar tumours: surgical-MRI correlation and use in differential diagnosis.

We compared the position of the normal pituitary gland as estimated by gadolinium (Gd)-DTPA-enhanced MRI, with its position at surgery in 40 patients with intra- and juxtasellar tumours: 22 pituitary adenomas, 4 craniopharyngiomas, 7 meningiomas, 2 germinomas, and 5 Rathke cleft cysts. In 37 of these, the normal gland showed more intense contrast enhancement than the adjacent tumour, from which it could be differentiated by Gd-DTPA-enhanced MRI, especially in the sagittal plane. The direction of displacement of the normal pituitary gland correlated well with tumour type, so that its position proved helpful in the differential diagnosis. The normal gland was typically displaced superiorly by pituitary adenomas, inferiorly by craniopharyngiomas, and anteriorly by germinomas. It showed variable displacement by Rathke cleft cysts, and was not usually displaced by meningiomas.

Adenoma↗

PubMed1994

An unusual presentation of spontaneous pneumoperitoneum secondary to the rupture of a gas-containing pyogenic liver abscess: report of a case.

We describe a rare case of spontaneous pneumoperitoneum secondary to the rupture of a gas-containing pyogenic liver abscess in a 59-year-old man. The patient was diagnosed as having a hollow viscus perforation based on a sudden onset of acute abdominal pain along with radiological evidence of bilateral subphrenic feee air (pneumoperitoneum), and underwent an emergency laparotomy. Contrary to expectations, the surgery revealed no perforations of the hollow viscus, but instead a ruptured liver abscess at the dome of the right hepatic lobe was identified associated with suppurative peritonitis. To the best of our knowledge, such a case of spontaneous pneumoperitoneum secondary to the rupture of a gas-containing liver abscess is extremely rare.

Abdomen, Acute↗

PubMed1994

Cytogenetic study of a severe case of Pallister-Killian syndrome using fluorescence in situ hybridization.

Usually, the supernumerary isochromosome 12p characterizing Pallister-Killian syndrome patients was detected in cultured skin fibroblasts but not in cultured blood lymphocytes. The proband of this study was a one-day-old female, who presented with major clinical characteristics of the Pallister-Killian syndrome, and had severe malformations in the form of anal atresia, cleft palate, and severe laryngomalacia. Chromosome preparations from cultured blood lymphocytes and skin fibroblasts, as well as buccal smears, from this patient were analyzed by fluorescence in situ hybridization (FISH) using a chromosome 12-specific alpha satellite probe. The proportions of cells showing positive signals for i(12p) in these samples were found to be 20, 62.5, and 70%, respectively. Repeated FISH studies of buccal smears from this patient showed considerable decreases in the proportions of i(12p) containing cells to 40% at one year of age and to 32% at the age of one year and five months. The decline in the percentage of i(12p)-containing cells in buccal smears with aging supports the concept of in vivo loss of the marker during repeated cell division.

Abnormalities, Multiple↗

PubMed1994

Nootropic effect of nicotine on carbon monoxide (CO)-induced delayed amnesia in mice.

The effects of nicotine on carbon monoxide (CO)-induced amnesia in mice were investigated using a step-down type passive avoidance task. Mice were exposed to CO 3 times at 1-h intervals, 7 days before the first training and retention test and 24 h after the first training session. Memory deficiency occurred in mice when training commenced more than 3 days after CO exposure (delayed amnesia): the median step-down latency in the retention test of the CO-exposed group was significantly shorter than that of the control group. Administration of (-)-nicotine (15.6 and 31.3 nmol/kg, IP) 15 min before the first training session prolonged the step-down latency in the CO-exposed group, but (+)-nicotine did not. To determine whether this effect of (-)-nicotine was mediated via nicotinic cholinergic receptors, we attempted to block its action using a nicotinic acetylcholine receptor antagonist (mecamylamine). Mecamylamine (1.25 mumol/kg) blocked the effect of (-)-nicotine (31.3 nmol/kg) on delayed amnesia. Administration of (-)-nicotine (15.6-62.5 nmol/kg) immediately after the first training session failed to ameliorate learning ability in the CO-exposed group. These results suggest that (-)-nicotine potentiates the nicotinic cholinergic neuronal system and may potentiate acquisition of memory.

Amnesia↗

PubMed1994

Antibodies to 65Kd heat-shock protein were elevated in rheumatoid arthritis.

Antibodies to 65Kd heat-shock protein (hsp) of mycobacterium leprae were measured by enzyme-linked immunosorbent assay (ELISA) in the three immunoglobulin classes in paired sera and synovial fluids of patients with rheumatoid arthritis (RA). Titers of anti-hsp antibody were expressed by optical density (OD) values for sera or indexes (OD values divided by amounts of immunoglobulin in each class) for synovial fluids and for their paired sera. Indexes of anti-hsp antibody were higher in synovial fluids than those in sera at 15/18 for IgG, 17/18 for IgA and 16/18 for IgM class. These results suggest the participation of anti-hsp antibodies to synovitis in RA.

Antibodies↗

PubMed1994

A case of hepatocolic fistula after percutaneous drainage for a gas-containing pyogenic liver abscess.

We describe a rare case of gas-containing pyogenic liver abscess which penetrated the adjacent colon, forming a hepatocolic fistula, after percutaneous transhepatic abscess drainage (PTAD) had been performed. To the best of our knowledge, this is the first report of hepatocolic fistula associated with a gas-forming liver abscess in a diabetic patient, with radiological and surgical confirmation of the fistula.

Colonic Diseases↗

PubMed1994

Milk transfer and tissue uptake of mercury in suckling offspring after exposure of lactating maternal guinea pigs to inorganic or methylmercury.

Maternal guinea pigs were injected with mercuric chloride (HgCl2; 1 mg Hg/kg body weight) or methylmercury (MeHg; 1 mg Hg/kg) 12 h after parturition, and exposure of the offspring to mercury (Hg) via breast milk were studied on days 3, 5 and 10 postpartum. Milk Hg concentrations were lower than maternal plasma Hg concentrations regardless of the form of Hg given to the dams. Milk Hg was higher in HgCl2-treated dams than in MeHg-treated dams. In MeHg-treated dams, MeHg was separately determined. While the ratio of MeHg to T-Hg decreased in the dams' plasma, it did not in the milk. There was a strong correlation between milk and plasma T-Hg concentrations in HgCl2 treated dams. In the milk of MeHg-treated dams, the plasma MeHg concentrations correlated better than did the plasma T-Hg concentrations. In the offspring, regardless of the chemical forms of Hg given to the dams, the highest Hg concentrations were found in the kidney, followed by the liver and the brain. Brain Hg concentrations were, however, significantly higher in the offspring of MeHg-treated dams than in those of HgCl2-treated dams. In addition, Hg levels in the major organs of the offspring of HgCl2-treated dams peaked on day 5 postpartum, while those of MeHg-treated dams did not show a significant decrease up to day 10 postpartum. These facts indicate that the two chemical forms of Hg were transferred to the offspring via the breast milk and were distributed differently, depending on the chemical form, to the offspring's tissues.

Animals↗

PubMed1994

Brain selenium status and behavioral development in selenium-deficient preweanling mice.

The influence of Se deficiency on behavioral development in preweanling mice was evaluated. Female ICR mice were fed either Se-deficient or control diet (containing < 20 or 400 ng Se/g diet, respectively) from 4 weeks before conception to the end of the suckling period. In the offspring of Se-deficient dams, liver and brain Se levels were reduced to < 5% and 60% of those in the control offspring, respectively, from as early as the third postnatal day. At weaning, brain Se content exceeded the hepatic one in Se-deficient offspring, whereas in the control offspring the liver contained 10 times more Se than the brain did. Thus, tissue-specific metabolism of Se was already functioning during the neonatal period. When placed in a thermogradient and allowed to move along the gradient, Se-deficient offspring exhibited a preference for a significantly warmer environment than did the controls. They also showed slightly retarded development of walking ability. These results showed that Se-deficient offspring differed from the controls in behavioral development. Possible mechanisms of these alterations are discussed.

Animals↗

PubMed1994

Orbital lobe lacrimal ductal cyst.

Lacrimal ductal cysts are rare, especially in the orbit. A case of lacrimal ductal cyst in the orbital lobe, revealed by computed tomography and magnetic resonance imaging, is described in a 16-year-old man who was successfully treated by complete surgical excision. The radiologic and clinical features of this type of lacrimal ductal cyst are discussed.

Adolescent↗

PubMed1994

Comparison of three-dimensional phase-contrast magnetic resonance angiography with three-dimensional time-of-flight magnetic resonance angiography in cerebral aneurysms.

Magnetic resonance angiography (MRA) can be divided into two types: namely, the phase-contrast (PC) method and the time-of-flight (TOF) method. The purpose of this study is to determine which method is better suited to demonstrate cerebral aneurysms. In a total of 27 cerebral aneurysms confirmed by cerebral angiography, both three-dimensional (3-D) PC and 3-D TOF methods were performed, and the corresponding findings were compared with conventional cerebral angiographic findings. Aneurysm visualization was grouped into three categories: "good" when clearly distinguishable, "fair" if distinguishable when reconstructed, and "poor" if completely undistinguishable. All MRAs were independently interpreted by two neurosurgeons in our institute. Sensitivity was 92.6% when MRA was performed with the TOF method, whereas it was 70.4% when performed with the PC method. In conclusion, the TOF method was more useful for demonstrating the aneurysms than the PC method due to its higher spatial resolution and shorter imaging time.

Adult↗

PubMed1994

Regulation of the action potential configuration by taurine in guinea-pig ventricular muscles.

1. Effects of taurine on the action potentials in guinea-pig ventricular muscle were examined at different extracellular Ca2+ concentrations ([Ca]o). Experiments were exerted by conventional microelectrode technique at 36 degrees C. 2. At normal Tyrode solution ([Ca]o = 1.8 mM), taurine (10 and 20 mM) had little or no effect on the 50%, 75% and 90% repolarizations of action potential duration (APD). 3. When [Ca]o was 3.6-10.8 mM [Ca]o, the APD shortening was produced [Ca]o-dependently, which was potentiated by addition of taurine. 4. To the contrary, at low [Ca]o (0.9 mM), the APD was prolonged. Taurine (10 and 20 mM) potentiated to prolong the APD. 5. The amplitude of action potential was depressed by taurine. The resting potential was unaffected. The responses to taurine were almost reversible. 6. Under the calcium overload condition ([Ca]o = 10.8 mM) in which a delayed afterdepolarization and spontaneous action potentials occurred, taurine (10 mM) abolished them completely. 7. These results indicate that taurine causes a dual action on the APD dependent on [Ca]o, and simultaneously reduces the cellular Ca2+ level in calcium overloading muscles.

Action Potentials↗

PubMed1994

Elevation of intracellular Ca2+ concentration by protein kinase C stimulation in isolated single rabbit sino-atrial node cells.

1. Effects of phorbol esters (stimulators of protein kinase C, PK-C) on the L-type Ca2+ current (ICa) and the intracellular Ca2+ level ([Ca]i) were investigated using single rabbit sino-atrial (SA) node cells. 2. In whole-cell patch-clamp experiments, both phorbol esters (1 microM). 4-beta-phorbol-12,13-dibutyrate (PDB) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA), inhibited the ICa. Phorbol esters did not affect the voltages of half-maximum activation and inactivation for ICa. 3. The time-course of inactivation phase for ICa was two exponentials. The fast component was decreased, whereas the slow component was increased by phorbol esters. 4. Addition of H-7 (10 microM), an inhibitor of PK-C, did not antagonize, but rather increased both components. In contrast, 4-alpha-phorbol-12,13-didecanoate (PDD), an inactive analog, did not affect the ICa amplitude and the inactivation process. 5. The phorbol esters elicited a transient inward current by repetitive clamp pulses. 6. In SA node cells loaded with fura-2 (a Ca(2+)-sensitive fluorescent dye), both TPA and PDB at 0.3 microM in the presence of isoproterenol (ISP, 0.2 microM) elevated the [Ca]i. PDD did not affect [Ca]i. 7. These results indicate that PK-C stimulation by phorbol esters elevates [Ca]i (which is potentiated by ISP), possibly resulting in cellular calcium overload.

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