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H Ueda

Publications and source records attributed to H Ueda.

At least 523 records · Page 29Linked to original sources
PubMed1994

Direct expression of a synthetic gene in Escherichia coli: purification and physicochemical properties of human initiation factor 4E.

An artificial synthetic gene coding for human eIF-4E was cloned into an expression vector and direct expression was attempted in Escherichia coli [BL21(DE3) strain] under the control of T7 promoter. The active gene product which was induced in high yield (ca. 4 mg/100 ml) by isopropyl-beta-D-thiogalactopyranoside was purified to homogeneity by a two-step chromatographic procedure with a good yield (ca. 74%), and was confirmed to be recombinant human eIF-4E by amino acid composition and sequence analyses, isoelectric focusing, and absorption spectral measurements. The identity of three-dimensional structures between the recombinant and native human eIF-4Es was confirmed by CD and fluorescence measurements.

Amino Acid Sequence↗
PubMed1994

Binding of enkephalin/dextran conjugates to opioid receptors.

[ala2]Enkephalin molecules were connected to dextran, and the affinities of the enkephalin/dextran conjugates for opioid receptors were studied. Two kinds of enkephalin derivatives, YaGFLGK-NH2 and YaGFLGS'S'PS'S'PS'KP-OMe (S' represents a Sar residue) were prepared. They retained the high affinity of the enkephalin unit toward opioid receptors. On the other hand, receptor affinity of the enkephalin derivative/dextran conjugates became lower than that of the enkephalin derivatives. Fluorescence from the Tyr residue of the conjugates in a buffer solution was less quenched by succinimide than that of the enkephalin derivatives. Therefore, in these conjugates, the binding of the enkephalin moieties to receptors should be hindered by a steric effect of the dextran matrix. However, the receptor affinity (as defined on the basis of an enkephalin unit) increased on increasing the amount of enkephalin units connected to the dextran matrix, especially in the case of the connection through a shorter spacer arm, suggesting simultaneous binding to a few receptors by the conjugate.

Amino Acid Sequence↗
PubMed1994

Mediators of activation of fushi tarazu gene transcription by BmFTZ-F1.

Transcriptional activation by many eukaryotic sequence-specific regulators appears to be mediated through transcription factors which do not directly bind to DNA. BmFTZ-F1 is a silkworm counterpart of FTZ-F1, a sequence-specific activator of the fushi tarazu gene in Drosophila melanogaster. We report here the isolation of 18- and 22-kDa polypeptides termed MBF1 and MBF2, respectively, that form a heterodimer and mediate activation of in vitro transcription from the fushi tarazu promoter by BmFTZ-F1. Neither MBF1, MBF2, nor a combination of them binds to DNA. MBF1 interacts with BmFTZ-F1 and stabilizes the BmFTZ-F1-DNA complex. MBF1 also makes direct contact with TATA-binding protein (TBP). Both MBF1 and MBF2 are necessary to form a complex between BmFTZ-F1 and TBP. We propose a model in which MBF1 and MBF2 form a bridge between BmFTZ-F1 and TBP and mediate transactivation by stabilizing the protein-DNA interactions.

Animals↗
PubMed1994

The Drosophila nuclear receptors FTZ-F1 alpha and FTZ-F1 beta compete as monomers for binding to a site in the fushi tarazu gene.

The striped pattern of fushi tarazu (ftz) expression found in the blastoderm of the Drosophila melanogaster embryo is generated largely through complex interactions between multiple transcription factors that bind to the zebra element of the ftz gene. A motif in the zebra element, the FTZ-F1 recognition element (F1RE), has been shown to bind a transcription factor, FTZ-F1 alpha, that is a member of the nuclear receptor family. We recently identified a second, related member of this family, FTZ-F1 beta, that also binds to this motif. To investigate the possibility that FTZ-F1 alpha and FTZ-F1 beta coregulate ftz transcription through the F1RE, we have studied the DNA binding properties of FTZ-F1 alpha and FTZ-F1 beta. We demonstrate that recombinant FTZ-F1 alpha and FTZ-F1 beta proteins produce similar in vitro DNase I footprint patterns on a 14-nucleotide region of the zebra element and bind to this site with similar affinities and sequence specificities. Using wild-type and N-terminally truncated receptors, we have determined that FTZ-F1 alpha and FTZ-F1 beta both bind as monomers to the 9-bp F1RE in the zebra element, as well as to an imperfect inverted F1RE repeat present in the Drosophila alcohol dehydrogenase gene. A polyclonal antibody raised against FTZ-F1 beta identifies a predominant F1RE-binding component in embryonic nuclear extracts. Although FTZ-F1 alpha is also present in these extracts, FTZ-F1 alpha and FTZ-F1 beta do not appear to form heterodimers with each other. Cotransfection assays in mammalian cell culture indicate that both receptors contribute to the net transcriptional activity of a reporter gene through their direct interaction with the F1RE. These data suggest that FTZ-F1 alpha and FTZ-F1 beta likely coregulate common target genes by competition for binding to a 9-bp recognition element.

Animals↗
PubMed1994

Effect of 15-deoxyspergualin on accelerated rejection in rat heart transplantation.

The effect of 15-deoxyspergualin (DSG) on accelerated rejection was evaluated using a rat heart transplantation model. Lewis rats (LEW, RT1l) served as the organ recipient and Brown Norway rats (BN, RT1n) as the donor. In the accelerated rejection model, the LEW recipient was sensitized with BN skin and BN heart was transplanted 7 days later; the heart graft was rejected within 2 days (n = 7). Histologically, the graft showed coagulation necrosis and hemorrhage throughout the myocardium. DSG (2.5 mg/kg/day) was administered to the recipient under the following three protocols: group 1: during the sensitization period (7 days); group 2: from 3 days after the sensitization to 2 days after grafting (7 days), and group 3: immediately after heart transplantation. The mean graft survival period in groups 1, 2, and 3 was 4.3 +/- 0.8 days (n = 7, p < 0.01 vs untreated host), 11.7 +/- 2.1 days (n = 7, p < 0.001, vs. untreated host), and 2.0 +/- 0 days (n = 6), respectively. The rejected grafts in groups 1 and 3 histologically showed coagulation necrosis and hemorrhage. By contrast, in group 2, the major histological change was interstitial lymphocyte infiltration and there were few findings such as coagulation necrosis or hemorrhage. In the complement-dependent cytotoxicity test, serum obtained at the second posttransplant day from the recipients treated in group 1 showed a high cytotoxicity level, although the cytotoxicity level of serum obtained from the recipients treated in group 2 was consistently low.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Transforming growth factor-beta stimulates, and glucocorticoids and epidermal growth factor inhibit brain natriuretic peptide secretion from cultured human amnion cells.

We previously reported the massive secretion of brain natriuretic peptide (BNP) from human amnion cells and suggested the possible role of BNP in the maintenance of human pregnancy. In this study, to elucidate the regulatory mechanism of BNP secretion from amnion cells, we measured the BNP level in the culture medium of amnion cells by RIA after incubation in the presence of various substances. Among the agents examined, cortisol (1 x 10(-7) to 1 x 10(-6) mol/L), dexamethasone (1 x 10(-8) to 1 x 10(-6) mol/L), and epidermal growth factor (EGF; 2 x 10(-11) to 2 x 10(-8) mol/L) inhibited BNP secretion from the cultured amnion cells in a dose-dependent manner. By contrast, transforming growth factor-beta (TGF beta; 4 x 10(-11) to 4 x 10(-9) mol/L) caused a 3- to 5-fold increase in BNP secretion. TGF beta-augmented BNP secretion was abolished by the addition of cortisol or EGF to the culture medium. Moreover, in this study, we revealed the presence of bioactive TGF beta in human amniotic fluid (approximately 4 x 10(-10) mol/L). The present finding of tight regulation of BNP secretion from amnion cells by cortisol, EGF and TGF beta, all at the concentrations physiologically present in human amniotic fluid, implies a physiological role of BNP secretion from amnion cells in the pregnant uterus.

Amnion↗
PubMed1994

Protective effects of hydroxychalcones on free radical-induced cell damage.

A number of hydroxychalcones were synthesized to evaluate their protective effects against oxidative cell damage and the production of superoxide anion. The hydroxychalcones which have a 3,4-dihydroxycinnamoyl structure were potent inhibitors of lipid peroxidation in rat liver microsomes. In particular, we found that 2',4',3,4-tetrahydroxychalcone (3) exhibited a potent inhibitory effect on H2O2-induced hemolysis due to an antioxidant effect. In addition, this compound strongly inhibited CCl4-induced cytotoxicity in primary cultured hepatocytes and substantially decreased the production of superoxide anion by rat peritoneal exudate macrophages.

Animals↗
PubMed1994

Protective effect of sodium L-malate, an active constituent isolated from Angelicae radix, on cis-diamminedichloroplatinum(II)-induced toxic side effect.

The effects of ingredients of Shi-Quan-Da-Bu-Tang (Juzen-taiho-to) on the nephrotoxicity and bone marrow toxicity caused by i.p. administration of 3 mg/kg cis-diamminedichloroplatinum (II) (CDDP) 9 times (on days 3, 4, 5, 6, 7, 8, 10, 11, 12) were examined in ddY mice s.c. inoculated with sarcoma 180 (S-180) cells on day 1. Angelicae Radix showed the strongest protective effect against the toxicity among the ingredients. The ED50 of a water extract of Angelicae Radix was 17.8 mg/kg for nephrotoxicity (indicated by an increase in blood urea nitrogen) and 59.4 mg/kg for bone marrow toxicity (indicated by a decrease in white blood cell count), when it was administered perorally (p.o.) on days, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15. The water extract did not exert any significant effect on the antitumor activity of CDDP. Bioassay-directed fractionation of the water extract resulted in isolation of a constituent having protective effects against the toxicity: sodium L-malate, C4H4Na2O5, was found to exhibit protective effects against both nephrotoxicity (ED50: 0.4 mg/kg, p.o.) and bone marrow toxicity (ED50: 1.8 mg/kg, p.o.), without reducing the antitumor activity of CDDP. These findings indicate that Angelicae Radix and its constituent sodium L-malate could provide significant protection against CDDP-induced nephrotoxicity and bone marrow toxicity without reducing the antitumor activity.

Animals↗
PubMed1994

[Signal transduction of cloned opioid receptors].

Complementary DNAs encoding delta, mu and kappa-opioid receptors have now been cloned and characterized. These receptors, which are members of the superfamily of seven transmembrane spanning receptors, share a high degree of amino acid sequence similarity among these receptors. From the similarity of the sequence, it is speculated that both the 1st and 2nd extracellular loop and the 4th membrane spanning domain are supposed to be involved in the opioid binding and subtype specificity. Because of the high similarity of the cytoplasmic regions' amino acid sequence, however, it seems that the signal transductions of delta, mu and kappa are very similar. In Xenopus oocytes expressing delta-opioid receptors and various kinds of GTP-binding protein alpha-subunits, the delta-agonist DSLET caused currents through Gi1 alpha (or Gi2 alpha)-phospholipase C mechanisms Neither G(o) alpha, Gq alpha, G11 alpha nor G14 alpha was involved in such delta-receptor-mediated responses. The higher concentration of DSLET (3-10 microM) showed a rapid desensitization upon repeated challenges. Such a rapid desensitization was purely homologous, and this was rescued by the pretreatment with protein kinase C inhibitor. Similar findings were also observed with mu and kappa-opioid receptors. These results suggest that the phosphorylation by protein kinase C is involved in the acute tolerance.

Amino Acid Sequence↗
PubMed1994

Action of FR901228, a novel antitumor bicyclic depsipeptide produced by Chromobacterium violaceum no. 968, on Ha-ras transformed NIH3T3 cells.

FR901228, a novel antitumor antibiotic, reversed the transformed morphology of the Ha-ras transformants, Ras-1 cells, and inhibited their growth. The reduction of c-myc expression was observed in FR901228-treated Ras-1 cells by RNA dot-blot hybridization. This reduction of c-myc expression and morphological reversion of the transformed cells to normal were correlated with growth inhibition (G0/G1 arrest in cell cycle).

3T3 Cells↗
PubMed1994

[Conception rate and embryo development in guinea pigs with synchronized estrus induced by progesterone implant].

Observations were made on the timing of mating and the pre-implantation development of fertilized eggs in guinea pigs synchronized by long-term progesterone treatment. Females received a subcutaneous implant of progesterone-filled silastic tubing for 14 days. Copulation was observed from the evening of day 4 to the morning of day 6 in 53 of 54 females (98%). Most of them (47/53, 89%) copulated on day 5 after removal of the tubing. Designating the day of copulation (day 5 after removal of the tubing) as day 0 of gestation, embryos collected from the genital tract were at the 4-cell, 8-cell, morula, and blastocyst stages on days 1, 3, 4 and 5 of gestation, respectively. Eggs were recovered at high incidence (85-100%) from days 1 to 5 of gestation. On day 6 gestation, no eggs were recovered from the genital tract, suggesting that implantation had occurred. The mean litter size (+/- S. D.) was 4.0 +/- 0.8 pups, which were born normally after a mean gestation period of 67 +/- 1 days in 7 synchronized females. Since the female guinea pigs synchronized by the long-term progesterone treatment had normal reproductive ability similar to that of cyclic females, this technique would make it possible to obtain animals at a scheduled time even in smaller-sized colonies. In addition, observations on the pre-implantation development of embryos in females with synchronized estrus might be a useful aid in the field of reproductive research.

Animals↗
PubMed1994

Thoracotomy in patients with liver cirrhosis.

Of 1030 patients requiring thoracotomy over a 7-year period, 11 had cirrhosis of the liver. The disease was severe (Child class C) in four patients, two of whom had recent variceal bleeding. Control patients with normal liver function recovered from post-thoracotomy hepatic disturbance within a week, but the cirrhotic patients required 2-3 weeks to regain baseline function. Although there were no perioperative deaths among the cirrhotic patients, management of significant pleural effusions required diuretics and plasma or albumin supplementation. Presence of cirrhosis, even advanced disease, need not contraindicate thoracotomy with skilled postoperative management, but the poor overall prognosis in Child class C cirrhosis calls for careful assessment of surgical indication.

Aged↗
PubMed1994

FR901228, a novel antitumor bicyclic depsipeptide produced by Chromobacterium violaceum No. 968. I. Taxonomy, fermentation, isolation, physico-chemical and biological properties, and antitumor activity.

A novel antitumor bicyclic depsipeptide, FR901228, was isolated from a broth culture of Chromobacterium violaceum No. 968 as colorless prisms and the molecular formula was determined as C24H36N4O6S2. This antibiotic reverted the transformed morphology of a Ha-ras transformant to normal, and exhibited prominent antitumor activities against murine and human tumor cell lines both in vitro and in vivo.

3T3 Cells↗
PubMed1994

FR901228, a novel antitumor bicyclic depsipeptide produced by Chromobacterium violaceum No. 968. III. Antitumor activities on experimental tumors in mice.

The antitumor activities of FR901228, (E)-(1S,4S,10S,21R)-7-[(Z)- ethylidene]-4,21-diisopropyl-2-oxa-12,13-dithia-5,8,20,23- tetraazabicyclo[8,7,6]-tricos-16-ene-3,6,9,19,22-pentanone, isolated from Chromobacterium violaceum No. 968, were studied in animals. FR901228 (ip) prolonged the life of mice bearing such murine ascitic tumors as P388 and L1210 leukemias and B16 melanoma, and inhibited (iv) the growth of murine solid tumors (Colon 38 carcinoma, M5076 reticulum cell sarcoma and Meth A fibrosarcoma) and human solid tumors (Lu-65 and LC-6 lung carcinomas, and SC-6 stomach adenocarcinoma) implanted in normal and nude mice, respectively. Its antitumor activity was especially potent against murine Meth A fibrosarcoma and human SC-6 stomach adenocarcinoma which were refractory to mitomycin C or cisplatin. FR901228 also was more effective against mitomycin C-, cyclophosphamide-, vincristine- and 5-fluorouracil-resistant P388 leukemias than against non-resistant P388 in mice. These results suggest that FR901228 will be a new type of drug for the treatment of cancer.

Animals↗
PubMed1994

Membrane skeleton in fresh unfixed erythrocytes as revealed by a rapid-freezing and deep-etching method.

A rapid-freezing and deep-etching method for examining en face the cytoplasmic aspects of unfixed erythrocyte membranes is described, which provides improved resolution. Normal human erythrocytes were centrifuged, washed in a phosphate buffer solution and pelleted. Glass coverslips were coated with 3-aminopropyl triethoxy silane and glutaraldehyde to make erythrocytes stick to them. A drop containing the erythrocyte pellet was sandwiched between 2 coverslips. The attached erythrocytes were slowly split open in the cytosol buffer solution. The specimens on coverslips were rapidly frozen in an isopentane-propane mixture (-193 degrees C), deeply etched and rotary shadowed with platinum and carbon. Filamentous structures were observed to form fine networks on the cytoplasmic side of erythrocyte membranes. The length of the filaments was shorter than that previously reported for glutaraldehyde-fixed filaments. The number of intersections between filaments was increased as compared with the previous data. It is concluded that dense in situ networks of short filaments beneath erythrocyte membranes can be viewed in a relatively intact state by splitting fresh unfixed specimens followed by the rapid-freezing and deep-etching method.

Cytoskeleton↗
PubMed1994

[Retroperitoneal lymph node dissection for patients with advanced testicular tumor].

We examined the indication for retroperitoneal lymph node dissection (RPLND) for 30 patients with advanced testicular tumor and made the following conclusion. The sequence of RPLND and primary chemotherapy made no difference in the therapeutic effect for patients with stage II A non-seminomatous germ cell tumor (NSGCT). However, we thought it better to administer primary chemotherapy prior to RPLND to prevent dissemination of tumor cells. Viable tumor cells often remained in retroperitoneal residual tumors even after chemotherapy in the patients with NSGCT advanced beyond stage II B. Therefore, RPLND seemed to be necessary if residual retroperitoneal tumors were found after the chemotherapy. In patients with seminoma, RPLND did not seem to be necessary if the residual tumor was less than 3 cm in diameter or the reduction rate of the retroperitoneal tumor was more than 80% after the initial therapy (chemotherapy or irradiation therapy.

Cisplatin↗