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H Satoh

Publications and source records attributed to H Satoh.

At least 469 records · Page 26Linked to original sources
PubMed1995

Estrogen-depleted condition induces apoptosis of rat mammary cancer cells after entering the S-phase of the cell cycle.

To elucidate the relationship of estrogen-depleted condition to apoptosis and tumor regression, 7,12-dimethylbenz[a]anthracene-induced mammary cancers of Sprague-Dawley rats were ovariectomized or treated with the anti-estrogenic agent epitiostanol after which proliferative activity and the incidence of apoptosis were investigated using the nick end labeling method, agarose gel electrophoresis of DNA, electron microscopy, the BrdU-labeling method and mitotic count. Tumor regression was found after 7-day treatment, and apoptosis induced by the agent on the 3rd day was clearly shown in both agarose gel electrophoresis of DNA and electron microscopy, which are two major methods used to judge apoptosis. The incidence of apoptosis revealed by the nick end labeling method reached its maximum, about threefold the control level, on the 3rd day of epitiostanol treatment compared with control tumors (P < 0.01). The incidence of the cells incorporating BrdU reached its maximum of 9.7% on the 2nd day of the treatment, while the incidence in tumors without treatment was 7.5% (P < 0.05). Subsequently, the incidence of apoptosis was reduced after 7-day treatment, and the incidence of BrdU-positive cells was significantly reduced to about 3% after 5-day treatment. The incidence of mitosis did not change until the 3rd day of the treatment and was reduced after 5-day treatment. Similarly, chronological changes of the incidences of BrdU-labeled cells, apoptotic cells and mitosis were observed in the tumors after ovariectomy. BrdU-labeled apoptotic bodies were detected in the tumors on the 3rd day in epitiostanol-treated rats that received a 6-hr bolus of BrdU before sacrifice.(ABSTRACT TRUNCATED AT 250 WORDS)

Androstanols↗
PubMed1995

Protective effects of glutathione isopropyl ester on the sensitivity of cultured cells to UVB irradiation.

The effect of glutathione (GSH) isopropyl ester on cellular sensitivity to UVB irradiation was investigated in HeLaS3 cells. Pretreatment with 0.1-0.5 mM GSH isopropyl ester for 4 h significantly inhibited the decrease of thymidine (TdR) incorporation caused by UVB irradiation at a dose of 500 J/m2, whereas pretreatment with a high dose (1 mM) had no effect. The colony formation ability of the pretreated cells (0.3 mM) was significantly better than that of cells that received irradiation only. When the cells were treated with GSH isopropyl ester, their intracellular GSH level increased dose-dependently over a 4 h period, suggesting that GSH isopropyl ester was transported into the cells and there converted to GSH. Within 2 min of exposure, the intracellular GSH level depleted rapidly to about 75% of that in non-irradiated normal cells. In contrast, the GSH level in cells pretreated with 0.3 mM GSH isopropyl ester was maintained at the same level as that in normal cells, indicating that the maintenance of intracellular GSH level is due to converted GSH from GSH isopropyl ester. These results clearly show that intracellular GSH is involved in cell protection against photodamage, and that GSH isopropyl ester is a useful antioxidant for protection against photooxidative injury.

Free Radical Scavengers↗
PubMed1995

Studies on differentiation inducers. V. Steroid glycosides from periplocae radicis cortex.

Six pregnane glycosides and three cardenolides were isolated as differentiation inducers using mouse myeloid leukemia (Ml) cells from Periplocae Radicis Cortex (bark of Periploca sepium BGE., Asclepiadaceae). The cardenolides showed much higher activities than the pregnane glycosides. Besides these nine compounds, commercially available cardenolides were tested for their differentiation inducing activities using Ml cells. Digitoxin and digoxin induced Ml cells into phagocytic cells, but others did not. In the presence of 1 nM of actinomycin-D, the activity of steroid glycosides was enhanced against Ml cells.

Animals↗
PubMed1995

Electrophysiological actions of taurine on spontaneously beating rabbit sino-atrial nodal cells.

Effects of taurine on the spontaneous action potentials in rabbit sino-atrial nodal cells were examined at different extracellular Ca2+ concentrations ([Ca]o). Experiments were performed at 36 degrees C. The firing rate of spontaneous activity was 132.5 +/- 12.1 beats/min (n = 18) in normal Tyrode's solution ([Ca]o = 1.8 mM). Increasing [Ca]o level from 0.9 to 10.8 mM significantly changed the maximum rate of depolarization. Other parameters of the action potentials were unaffected. When [Ca]o was 0.9 mM, application of taurine (1 to 20 mM) tended to cause a positive chronotropic effect and hyperpolarized the maximum diastolic potential. In the normal solution (at 1.8 mM [Ca]o), taurine significantly enhanced only the maximum rate of depolarization. In contrast, under high [Ca]o (5.4 and 10.8 mM), taurine at 1 and 5 mM had a negative chronotropic effect, but 20 mM taurine had a positive chronotropic effect. Also, taurine shortened the action potential duration and hyperpolarized the maximum diastolic potential. The maximum rate of depolarization was inhibited. In 10.8 mM [Ca]o solution, irregular spontaneous activity (dysrhythmias) occurred in 4 of 6 preparations, and addition of taurine (1 to 20 mM) abolished it. These results indicate that taurine modulates the action potential configuration in the sino-atrial nodal cells dependent on [Ca]o.

Action Potentials↗
PubMed1995

Depression of the spontaneous activity by phorbol esters in young embryonic chick cardiomyocytes.

Effects of phorbol esters, 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and 4-beta-phorbol-12,13-dibutyrate (PDB), that stimulate protein kinase C (PK-C) on the spontaneous action potential and the ionic currents in cultured embryonic chick ventricular cardiomyocytes were examined using whole-cell voltage-clamp and current-clamp modes. Experiments were performed at room temperature (22 degrees C). The firing rate of spontaneous activity was 61.7 +/- 1.6 beats/min (n = 12). Phorbol esters (100 nM and 1 microM) caused a negative chronotropic effect, and they inhibited the maximum rate of depolarization and the action potential amplitude. The action potential duration (at 50% repolarization) tended to decrease, and the maximum diastolic potential was unaffected. In whole-cell voltage-clamp experiments, both TPA and PDB inhibited the L-type Ca2+ current and the delayed rectifier K+ current. The fast time constant of the inactivation phase for the Ca2+ current was decreased, but the slow component was unaffected. In addition, PDB (100 nM) enhanced the T-type Ca2+ current, accompanied with an increase in its time constant. In contrast, 4-alpha-phorbol-12,13-didecanoate (PDD), an inactive analogue on PK-C, failed to produce significant changes. These results suggest that the PK-C stimulation induced by phorbol esters might affect the ionic currents and modulate the [Ca]i, resulting in regulation of the spontaneous activity of embryonic chick heart cells.

Action Potentials↗
PubMed1995

Intracellular sodium concentration in diabetic rat ventricular myocytes.

We measured intracellular NA+ concentration ([Na+]i) of diabetic rat ventricular myocytes using sodium-binding benzofuran isophthalate (SBFI). We used diabetic rats at 8 weeks after the injection of streptozotocin (45 mg/kg i.v.). The level of [Na+]i during the control perfusion was significantly lower in diabetic myocytes than that in normal myocytes (9.2 +/- 0.4 mM v.s. 12.0 +/- 0.3 mM, p < 0.01). After the 40 min perfusion of 1 microM hexamethylene amiloride (HMA), [Na+]i decreased significantly in both groups. However, there was no difference in [Na+]i between the two groups after the perfusion of HMA. It was suggested that the lower [Na+]i in diabetic myocytes could be due to the decreased activity of Na+/H+ exchange system.

Amiloride↗
PubMed1995

Detection of reverse transcriptase activity by enzyme-linked immunosorbent assay in human immunodeficiency virus type 1.

An enzyme-linked immunosorbent assay (ELISA) using biotin-labelled oligo-dT primer and digoxigenin (Dig)-dUTP was designed to measure the reverse transcriptase (RT) activity of human immunodeficiency virus type 1 (HIV-1). The ELISA system involves the selective detection step of a newly synthesized cDNA by two specific bindings, biotin-streptavidin binding and alkaline phosphatase (AP)-conjugated anti-Dig-Dig binding, and the enzymatic amplification step to increase coloring generated by AP. This method was used to measure the activity of RT in the culture supernatants of peripheral leukocytes obtained from four anti-HIV-1-positive persons cocultivated with those from four anti-HIV-1-negative persons. RT activity was detected in all of four anti-HIV-1-positive culture supernatants but not in those cultivated with anti-HIV-1-negative supernatants alone. Thus, our improved ELISA for detection of HIV-1 appears to be sensitive enough and useful for routine laboratory work. This non-radioactive method will also be useful for detecting other retroviruses and for screening of RT inhibitors.

Cells, Cultured↗
PubMed1995

[Glioblastoma multiforme with liver metastasis--case report].

Extracranial metastasis of glioblastoma is rare. This is an autopsy case report of a patient with glioblastoma multiforme found to have metastasized to the liver. A 42-year-old woman was admitted with a chief complaint of headache. Physical and neurological examinations on admission showed no abnormalities. CT and MRI demonstrated a tumor in the left parietooccipital region with invasion into the subependymal area of the left lateral ventricular trig-one. A cerebral angiogram showed tumor staining in the same area. Subtotal tumor resection was performed uneventfully. The microscopic diagnosis was glioblastoma multiforme. Postoperatively, the patient underwent whole brain and local irradiation, and intra-arterial ACNU infusion therapy. One month later, she developed low back pain, probably due to spinal dissemination. Postmortem examination showed local recurrence of the tumor and subarachnoidal dissemination not only in the base of the skull but in the lower spinal cord. Tumor was also observed in the liver, but no lung or lymph node metastasis was detected. Metastasis to the liver in this patient is believed to have occurred via the anastomosis between the vertebral and portal venous system.

Adult↗
PubMed1995

The human thrombopoietin gene is located on chromosome 3q26.33-q27, but is not transcriptionally activated in leukemia cells with 3q21 and 3q26 abnormalities (3q21q26 syndrome).

We previously demonstrated that the EVI-1 gene was transcriptionally activated in the 3q21q26 syndrome and chromosomal breakpoints at 3q26 were clustered within 400 Kb of the EVI-1 gene. Since thrombocytosis is often observed in the 3q21q26 syndrome, we first mapped the thrombopoietin (TPO) gene and then we examined for transcriptional activation and chromosomal rearrangement of the TPO gene in four cases of the 3q21q26 syndrome. The TPO gene was assigned to chromosome 3q26.33-q27 by fluorescence in situ hybridization analysis. Although the TPO gene was mapped to the same locus as the EVI-1 gene, the distance between the TPO gene and the EVI-1 gene at 3q26 was more than 600 Kb and no gross chromosomal rearrangements of the TPO gene were detected by Southern blot analysis and pulsed field gel electrophoresis (PFGE) analysis. TPO transcripts were not detected in these leukemia cells by Northern blot analysis. These results indicate that activation of the TPO gene is not the main cause of thrombocytosis in the 3q21q26 syndrome.

Base Sequence↗
PubMed1995

The reproducibility of reported height and body weight in repeated questionnaire surveys.

Reproducibility of reported height and weight were studied via repeated questionnaire surveys distributed to subjects within a year. Effects of the factors which might influence the reproducibility of these values were investigated. Although only about half of the subjects reported the same height and 30% the same weight on the second questionnaire, no change was found in average height and weight after a one year interval for both male and female subjects. The reproducibility decreased with age for both height and weight. Smokers tended to have lower reproducibility for height than non-smokers. The shorter subjects had lower height reproducibility than their taller counterparts, while heavier subjects had lower weight reproducibility than light subjects. It was observed that the lower the weight reproducibility, the lower the height reproducibility and vice versa. Reported height or weight figures ending in zero or five were more frequent than the expected 10% with low reproducibility.

Adult↗
PubMed1995

[A case of cutaneous malignant melanoma metastatic to the choroid].

A case of metastasis of cutaneous malignant melanoma to the choroid was reported. The patient, a 61-year-old man, had undergone an amputation of his right first finger 3 years ago due to cutaneous malignant melanoma. Ophthalmoscopic examination revealed a whitish yellow elevated choroidal lesion and serous retinal detachment in the left eye. Fluorescein angiography demonstrated multiple pinpoint leaks in the early phase and progressive pooling of dye into the subretinal space in the late phase. In magnetic resonance imaging, the tumor showed a hyperintense image in both T1 and T2-weighted images. Autopsy was performed and histopathological examination of the eye showed that the tumor cells were polygonal in shape, and had round or oval nuclei, but the cytoplasms had little melanin pigment. Immunohistochemistry for S-100 and HMB-45 antibody showed positive staining in choroidal tumor and other metastatic lesions, indicating that they were metastatic tumors from cutaneous malignant melanoma (amelanotic melanoma cells).

Choroid Neoplasms↗
PubMed1995

A comparison of mass balance, pharmacokinetics and disposition of [14C(U)]- and [125I]recombinant human interleukin-2 in cynomolgus monkeys.

Recombinant human interleukin-2 (rHuIL-2) has been metabolically labeled with 14C amino acids in Escherichia coli and affinity purified on a rHuIL-2 receptor affinity column. The radiolabeled molecule had a specific radioactivity of 238 dpm/unit and the identical amino acid sequence and biological activity as unlabeled rHuIL-2. In this study, we used this labeled [14C(U)]rHuIL-2 and commercially available [125I]rHuIL-2 (identical in sequence to the [14C(U)]rHuIL-2) to compare the mass balance, pharmacokinetics, and disposition in cynomolgus monkeys. After a single intravenous bolus dose of 4 x 10(5) units/kg, serum samples were collected for 7 days and examined for biological activity, total radioactivity, and by molecular size exclusion chromatography. Urine and feces were analyzed for total radioactivity. When analyzed for biological activity, both [14C(U)]- and [125I]rHuIL-2 exhibited the following pharmacokinetic parameters: terminal elimination half-life of 1-2 hr, AUC0-infinity ranged from 2005 to 4659 units x hr/ml, clearance was 90-200 ml/hr/kg, and volume of distribution ranged from 103 to 163 ml/kg. Comparison of the pharmacokinetic profiles of the two radiolabels were very different from bioactivity, in that the elimination half-lives for radioactivity were approximately 8 days and 10 hr for [14C(U)]- and [125I]rHuIL-2, respectively. We conclude that the [14C(U)]rHuIL-2 was metabolized to constituent amino acids and recycled into newly synthesized proteins from our size exclusion chromatography studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1995

A novel synthesis of antineoplastic 4'-thionucleosides using D-glucose as a chiral synthon.

We have synthesized 2'-deoxy-2'-methylene-4'-thiocytidine as a potential antineoplastic agent. Isopropylidene-3-O-benzylxylose, readily obtained from D-glucose in 5 steps, was converted to 1,4-anhydro-4-deoxy-4-thio-arabinitol. After manipulation at 2-position, unique Pummerer type glycosylation at the alpha-position of sulfoxides gave the target compound. Antineoplastic effect of this compound is also reported.

Antineoplastic Agents↗
PubMed1994

Diagnosis of t(2;5)(p23;q35)-associated Ki-1 lymphoma with immunohistochemistry.

Some Ki-1 lymphomas carry a specific chromosomal translocation, t(2;5)(p23;q35). We have recently found a novel hyperphosphorylated 80-kD protein tyrosine kinase, p80, in a human Ki-1 lymphoma with this translocation. Subsequent cDNA cloning showed that p80 is a fusion protein of two different genes on chromosome 2p23 and 5q35, the novel tyrosine kinase gene and nucleophosmin gene, respectively. In this study, we intended to detect p80 on lymphoma tissues with immunologic methods. Thus, we developed rabbit polyclonal antibody using a synthetic peptide corresponding to a part of its kinase domain. The antibody (anti-p80) immunoprecipitated and immunoblotted p80 specifically from AMS3. Then, to examine whether t(2;5)(p23;q35) was present on biopsied lymphomas, reverse transcriptase-polymerase chain reaction (RT-PCR) covering the fusion junction of p80 mRNA was performed. Among 10 Ki-1 lymphomas and 10 additional lymphomas other than the Ki-1 lymphomas, expression of p80 mRNA was detected in three cases exclusively. When these 20 cases and additional 30 lymphomas were immunostained with anti-p80, positive staining was noted exclusively in the three cases found by PCR to have harbored the p80 mRNA. Thus, the present immunostaining, as well as PCR, was shown to be efficient for detecting lymphomas producing this chimeric protein/mRNA.

Amino Acid Sequence↗
PubMed1994

Simultaneous measurement of [Na+]i and Ca2+ transients in an isolated myocyte: effects of strophanthidin.

We have developed a new method to measure [Na+]i and Ca2+ transients of a beating cardiac myocyte using a Na(+)-sensitive fluorescent probe, sodium-binding benzofuran isophthalate (SBFI) and a Ca(2+)-sensitive fluorescent probe, fluo-3. There was no interaction between two probes, and the artifact due to contraction could be eliminated in the measurement of [Na+]i. [Na+]i in guinea pig ventricular myocytes stimulated at 1 Hz was 8.0 +/- 0.7mM. Strophanthidin (10 microM), initially, increased the amplitude and the basal level of Ca2+ transients in association with an increase in [Na+]i. When arrhythmias were induced, the amplitude of Ca2+ transients decreased while [Na+]i and the basal level of Ca2 transients continued to increase. These results suggested that the diastolic [Ca2+]i was closely related to [Na+]i. However, the systolic [Ca2+]i, which could be influenced by other factors, was dissociated from [Na+]i in the condition of Ca2+ overload.

Aniline Compounds↗
PubMed1994

The role of Na+/H+ exchange and the Na+/K+ pump in the regulation of [Na+]i during metabolic inhibition in guinea pig myocytes.

To investigate the mechanisms of Na+ loading during metabolic inhibition (MI), [Na+]i and pHi were measured in quiescent guinea pig myocytes using fluorescent probes, sodium-binding benzofuran isophthalate and 2,7,bis(carboxyethyl)-5,6-carboxyfluorescein. When myocytes were exposed to MI (3.3 mM amobarbital and 5 microM carbonyl cyanide m-chlorophenylhydrazone, without glucose) for 20 min, [Na+]i increased from 8.3 +/- 0.7 mM to 17.7 +/- 1.3 mM (p < 0.01) and pHi decreased from 7.22 +/- 0.03 to 7.00 +/- 0.04 (p < 0.05). The inhibition of Na(+)-H+ exchange by hexamethylene amiloride (HMA) significantly attenuated the increase in [Na+]i during MI (9.3 +/- 0.9 mM; p < 0.01 vs MI without HMA). When a K(+)-free solution was perfused to inhibit the Na+/K+ pump in the presence of HMA, there was an immediate increase in [Na+]i during MI. Perfusion of a K(+)-free solution after 10 min of MI caused no change in the rate of the increase in [Na+]i. We concluded that 1) Na+/H+ exchange was an important mechanism for Na+ elevation during MI, and 2) the Na+/K+ pump was functional during the early phase of MI, but was inhibited 10 min after MI in this model.

Amiloride↗
PubMed1994

Roles of heme iron-coordinating histidine residues of human hemopexin expressed in baculovirus-infected insect cells.

Hemopexin (Hx), the major heme-binding plasma glycoprotein, scavenges circulating heme and performs an antioxidant function. In the present study, human Hx was expressed in a baculovirus system and its presumed essential His residues were mutated to Thr as a means of investigating their participation in heme binding. The recombinant Hx proteins were purified by sequential chromatography on Con A-agarose and SP-Sepharose. The purified recombinant wild-type Hx retained its heme binding. The binding constant for heme was considerably reduced, however, suggesting that glycosylation contributes critically to the heme binding property of Hx. Mutation either at His-127 or at His-56 plus His-127, but not at His-56 per se, reduced the affinity for heme by an order of magnitude relative to wild-type Hx. It is concluded that His-127 contributes to the high affinity for heme. We recorded proton NMR spectra to investigate the possibility that the degree of high-spin content is increased by deletion of an axial His-iron coordination. 1H NMR data indicate that each of the single-mutant heme-Hx complexes is predominantly low-spin, perhaps owing to coordination of the heme iron by the Thr side-chain oxygen or water oxygen coordinating to the iron.

Animals↗