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Y Sugimoto

Publications and source records attributed to Y Sugimoto.

At least 343 records · Page 19Linked to original sources
PubMed1994

Human aldolase B: liver-specific properties of the isozyme depend on type B isozyme group-specific sequences.

A series of chimeric enzymes between two human aldolases A, B or C were constructed to identify the molecular regions responsible for isozyme-specific functions. Chimeras constructed between aldolases A and B were AB34 (an AB chimera connected at position 34), ABA34-306 and ABA212-306 (the ABA chimeras). Those between aldolases B and C are BC243, BC263 and BC306 (the BC chimeras connected at positions as indicated), as well as CB55, CB243, CB263 and CB306 (the CB chimeras connected at positions as indicated), CBC55-263 (a CBC chimera), and BCB55-193, BCB55-306, BCB79-193 and BCB79-306 (the BCB chimeric enzymes). Through the analysis of the properties of these chimeras, it was found that for aldolase B, isozyme B group-specific sequences (IGSs)-1 and -4 were required for exerting type B-specific functions, while the IGSs-2 and -3 enhanced, in collaboration with the IGS-1, the catalytic activity of aldolase B. In addition, the alpha/beta-barrel and the restricted stretches, which were not specified but occupied two distinct regions spanning the amino acid positions 108-137 (designated connector 1) and 243-306 (designated connector 2), were found to be indispensable for showing full catalytic activity of aldolase B.

Amino Acid Sequence↗
PubMed1994

Characterization, expression, and immunohistochemical localization of 5 alpha-reductase in human skin.

Human skin has been shown to contain a high level of 5 alpha-reductase activity, the enzyme that catalyses the conversion of the weak androgen testosterone into dihydrotestosterone, the most potent androgen. Because two types of 5 alpha-reductase genes have been characterized in humans, we have cloned 5 alpha-reductase cDNAs from adult human keratinocyte and skin fibroblast cDNA libraries to identify and gain better knowledge of the 5 alpha-reductase expressed in normal human skin. Nucleotide sequence analysis shows that the clones obtained correspond to the type I 5 alpha-reductase. RNase protection analysis using (poly A)+ RNA obtained from human skin and prostate also confirms that type I 5 alpha-reductase is the predominant type expressed in normal skin, whereas type II 5 alpha-reductase is the major form found in the prostate. Following polymerase chain reaction amplification of human keratinocyte and skin fibroblast cDNA, a low level of type II 5 alpha-reductase cDNA has been detected. Using antipeptide antibodies raised in rabbits against the peptide sequence covering amino acids 227 -240 to perform immunohistochemical localization of 5 alpha-reductase, we have found that 5 alpha-reductase is distributed in sweat and sebaceous glands, as well as in the epidermal cell layers, thus providing the basis for the important role of androgens in human skin and its appendages.

Base Sequence↗
PubMed1994

[A case of adult Chlamydia pneumoniae pneumonia diagnosed from a culture method].

We diagnosed a 41-year-old female patient to be suffering from Chlamydia pneumoniae (C. pneumoniae) by using PCR and culture methods. She had a prolonged dry cough and slight fever. Her chest roentgenogram showed a segmental infiltration in the middle of the right lung field. We treated her with 400 mg of cefpodoxime proxetil (CPDX-PR) per day. On the 4th day after beginning the treatment with CPDX-PR, she still complained of a productive cough. We changed the treatment by using 300 mg of roxithromycin per day and these symptoms disappeared. To diagnose C. pneumoniae early, PCR, MIF and culture methods are very useful diagnostic tools.

Adult↗
PubMed1994

Distinct cellular localization of mRNAs for three subtypes of prostaglandin E receptor in kidney.

Distribution of the mRNAs for three subtypes of prostaglandin E (PGE) receptors in the mouse kidney was investigated by in situ hybridization. The mRNA for EP1 subtype, which is coupled to Ca2+ mobilization, was specifically localized to the collecting ducts from the cortex to the papilla. The mRNA for EP2 subtype, which is linked to stimulation of adenylate cyclase, was localized to the glomeruli. The mRNA for EP3 subtype, which is coupled to inhibition of adenylate cyclase, was located densely in the tubules in the outer medulla and in the distal tubules in the cortex. These results exhibit distinct cellular localization of three subtypes of PGE receptor in the kidney and suggest that PGE2 exerts multiple functions via these subtypes expressed in different segments of the nephron.

Adenylyl Cyclases↗
PubMed1994

The role of ions on histamine-induced depolarization in isolated guinea pig adipocytes.

Effects of ions on histamine (Hi)-induced depolarization were studied in guinea pig adipocytes. Depolarization induced by Hi in guinea pig adipocytes was decreased by removal of K+ from the medium or pretreatment with ouabain at concentrations that showed no significant effect themselves. The decrease in membrane potentials induced by Hi was also abolished potently by replacement of Na+ by choline or pretreatment with tetrodotoxin at a concentration that caused no significant action alone. Pretreatment with monensin at a concentration lower than that eliciting the action resulted in a potentiation of Hi-induced depolarization. The depolarization induced by Hi was not affected by the presence of Ca2+ in the medium or pretreatment of the cells by diltiazem.

Adipocytes↗
PubMed1994

Glibenclamide-induced oscillation of canine coronary artery is independent of myocardial ischemia.

To investigate the in vivo role of the ATP-sensitive potassium channel (KATP) in the coronary arteries, we examined the effects of intravenous (i.v.) glibenclamide (GLB, 0.3, 1.0, and 3.0 mg/kg), a specific KATP blocker, in chronically instrumented dogs. Epicardial coronary artery diameter (CoD) and coronary blood flow (CBF) were measured continuously. CoD and CBF oscillated in all 6 dogs after injection of 3 mg/kg GLB. CoD oscillated only slightly, with a decrease of 2.3 +/- 0.4%; CBF showed marked oscillation, with a peak flow rate of 21.9 +/- 2.7 ml/min (+26.6%) and a trough flow rate of 10.3 +/- 2.9 ml/min (-46.3%) (baseline flow rate was 17.8 +/- 2.4 ml/min). GLB 1 mg/kg produced a slight decrease in CBF without oscillation, and at 0.3 mg/kg had almost no effect. These oscillations were not associated with a decrease in myocardial blood flow as measured by the hydrogen gas clerance method. Nicorandil (0.2 mg/kg), cromakalim (20 micrograms/kg), and diltiazem (0.2 mg/kg) almost completely suppressed the GLB-induced oscillations, but nitroglycerin (NTG 15 micrograms/kg) did not. Thus, oscillation of large and small coronary arteries was induced by GLB and was independent of myocardial ischemia. In addition, these findings suggest that KATP has an important in vivo role in modulating large and small coronary artery tone through activation of the voltage-dependent Ca2+ channel.

Adenosine Triphosphate↗
PubMed1994

[Basic and clinical studies on serum cytokeratin 19 fragment assay using Centocor CYFRA 21-1 kit in patients with lung cancer].

We evaluated the newly developed tumor marker assay kit, "Centocor CYFRA 21-1", an immunoradiometric assay (IRMA) kit for determining the serum cytokeratin 19 fragment using the sera of healthy subjects, patients with benign lung diseases and patients with lung cancer. The assay procedure is simple and based on the one-step IRMA system. There were no problems in reproducibility, dilution test and recovery test. The minimum detectable dose was 0.3 ng/ml. The antigen measured by this kit was immunologically cross-reactive with tissue polypeptide antigen (TPA) and CYFRA 21-1 concentration was closely correlated with TPA concentration in the patient's serum (r = 0.86, p < 0.01). The cut-off value of serum CYFRA 21-1 based on the assay results of this kit was calculated to be 1.6 ng/ml from the receiver operating characteristic curve. Three of 47 healthy subjects (6.4%) and 9 of 30 patients with benign lung diseases (30.0%) showed a concentration over the cut-off value. By contrast, serum CYFRA 21-1 concentration was elevated in 31 of 50 patients with lung cancer (62.0%), 11 of 13 squamous cell carcinoma patients (84.6%), 8 of 12 small cell carcinoma patients (66.7%), 4 of 7 large cell carcinoma patients (57.1%) and 8 of 18 adenocarcinoma patients (44.4%). In addition, the positive rate of serum CYFRA 21-1 in patients with lung cancer gradually increased with staging of the disease: 50.0% in stage I, 50.0% in stage II, 61.9% in stage III, and 76.9% in stage IV. Thus, our results suggested that the Centocor CYFRA 21-1 kit is a useful assay system for serum cytokeratin 19 fragment as a tumor marker in patients with lung cancer.

Adult↗
PubMed1994

[Antitumor effect of SN-38, active form of CPT-11, on human colorectal cancer cell line].

The in vitro sensitivity testing for four human colorectal cancer cell lines to seven chemotherapeutic drugs including CPT-11, derivative of camptothecin, and its active form SN-38 were determined. MTT assay revealed that SN-38 was the most active for all four cell lines tested and its IC50's were very close to its clinically achievable plasma concentration. Relationship between exposure time and cytocidal effect of SN-38 was also investigated using MTT assay, topoisomerase-I (Topo-I) immunoblot analysis and DNA relaxation-assay, showing that IC50 value, Topo-I protein and Topo-I activity were decreased soon after the administration of SN-38 and reached to the plateau level at 24 hours. We conclude that SN-38 is very potent for colorectal cancer and the optimal schedule of CPT-11 can be the more continuous form of administration capable of as long as 24 hours exposure of its active metabolite, SN-38.

Antineoplastic Agents, Phytogenic↗
PubMed1993

Nucleosides and nucleotides. 123. Synthesis of 1-(2-deoxy-2-isocyano-beta-D-arabinofuranosyl)cytosine and related nucleosides as potential antitumor agents.

2'-Deoxy-2'-isocyano-1-beta-D-arabinofuranosylcytosine (8, NCDAC) has been synthesized as a potential antitumor antimetabolite from a corresponding 2'-azido-2'-deoxy-1-beta-D-arabinofuranosyluracil derivative 2a. Uracil and thymine analogues 6a and 6b of 8 were also prepared. Attempts to synthesize 2'-deoxy-2'-isocyanocytidine (14b) failed due to the insertion of the 2'-alpha isocyano group into the 3'-OH group, affording the 2',3'-oxazoline derivative 15b. Stability of the isocyano derivative 6a and 2',3'-oxazoline derivative 15a under basic and acidic conditions were examined. The isocyano group in 6a was stable in basic conditions but unstable even in weakly acidic conditions to furnish the corresponding 2'-beta formamide derivative 17. Compound 15a was easily hydrolyzed the corresponding 2'-alpha formamide derivative 16 on treatment with H2O at room temperature. The cytotoxicity of 8, 6a, and 6b was examined in mouse and human tumor cells in vitro and compared with that of ara-C. Of these nucleosides, 8 was moderately cytotoxic to these cell lines. In vivo antitumor activity of 8 against Lewis lung carcinoma cells was also investigated and 8 showed only moderate tumor volume inhibition.

Animals↗
PubMed1993

Opposite coupling of prostaglandin E receptor EP3C with Gs and G(o). Stimulation of Gs and inhibition of G(o).

We recently identified four isoforms of bovine prostaglandin E receptor EP3 subtype, which are coupled to different signaling pathways; EP3A is coupled to inhibition of adenylate cyclase, while EP3B and EP3C are coupled to its stimulation and EP3D is coupled to phosphatidylinositol turnover, in addition to the adenylate cyclase system (Namba, T., Sugimoto, Y., Negishi, M., Irie, A., Ushikubi, F., Kakizuka, Ito, S., A., Ichikawa, A., and Narumiya, S. (1993) Nature 365, 166-170). We examined here the identity of coupled G proteins and their regulation by one of the isoforms, EP3C, in the membranes of EP3C cDNA-transfected Chinese hamster ovary cells. M&B 28767, an EP3 agonist, stimulated the GTPase activity in the pertussis toxin (PT)-treated cell membrane, but inhibited it in the cholera toxin (CT)-treated cell membrane, while the agonist neither stimulated nor inhibited it in the both PT- and CT-treated cell membrane. In the PT- and CT-treated cell membrane reconstituted with various G proteins, M&B 28767 inhibited the GTPase activity of G(o), but stimulated that of Gs. On the other hand, M&B 28767 did not affect the GTPase activity of Gi1, Gi2, or Gi3. M&B 28767 increased the apparent affinity of G(o) for GDP without any change in that for GTP, as assessed by displacement of [35S]GTP gamma S (guanosine 5'-O-(3-thiotriphosphate)) binding to G(o). In contrast, M&B 28767 increased the apparent affinity of Gs for GTP but decreased that for GDP. These results demonstrated that the EP3 receptor isoform is coupled to two different G proteins, and oppositely regulates their activities, inhibition of G(o), and stimulation of Gs.

Alprostadil↗
PubMed1993

Spontaneous immortalization of mouse fibroblasts involves structural changes in senescence inducing protein, mortalin.

Mortalin, a novel member of mouse heat shock protein 70 (hsp70) family, is seen to distinguish the cellular mortal and immortal phenotypes by virtue of its cytosolic and perinuclear distribution, respectively. We report here that the cytosolic and perinuclear forms of mortalin from CD1-ICR mouse embryonic fibroblasts and NIH 3T3 cells, respectively, differ by two amino acids, can be distinguished on two-dimensional SDS-polyacrylamide gel. The perinuclear mortalins from RS-4 and Balb/c 3T3 cells harbor the same two amino acids as that of NIH 3T3 cells. However, these when analyzed with C-MEF mortalin did not exhibit the mobility shift equivalent to C-MEF and NIH 3T3 mortalins. The data indicate that the perinuclear mortalin from different immortal fibroblasts are not identical and implicate the possibility of additional structural changes in mortalin during immortalization. Such differences may also contribute to the differential in vitro growth characteristics of these immortal cells.

3T3 Cells↗
PubMed1993

Induction of cellular senescence by transfection of cytosolic mortalin cDNA in NIH 3T3 cells.

We have recently identified a novel member of hsp70 family (mortalin) as a mortality marker (Wadhwa, R., Kaul, S. C., Ikawa, Y., and Sugimoto, Y. (1993) J. Biol. Chem. 268, 6615-6621). It has distinct intracellular distribution in mortal and immortal fibroblasts. Here, we report that the cytosolic (mot-1) and the perinuclear (mot-2) forms of mortalin cDNA cloned from mortal and immortal cells, respectively, differ by only two bases in the open reading frame, resulting in two amino acid changes. The induced expression of the cytosolic form by transfection of mot-1 cDNA (isolate from CD1-ICR mouse embryonic fibroblasts) to NIH 3T3 cells induced cellular senescence. However, the perinuclear form expressed by mot-2 cDNA (isolate from NIH 3T3 cells) did not yield an equivalent effect. The data suggest the senescence-inductive function of cytosolic mortalin and implicitly point to a genetic event involved in immortalization.

3T3 Cells↗
PubMed1993

Third isoform of the prostaglandin-E-receptor EP3 subtype with different C-terminal tail coupling to both stimulation and inhibition of adenylate cyclase.

A functional cDNA clone for a third isoform of the mouse prostaglandin-E-receptor EP3 subtype, derived by alternative RNA splicing, named the EP3 gamma receptor, was obtained in addition to those for the two other isoforms, EP3 alpha and EP3 beta. The three isoforms are only different in the amino acid sequence of the putative cytoplasmic carboxy-terminal tail. When expressed, EP3 gamma shows identical ligand-binding properties to these of the other isoforms. The EP3-selective agonist, M&B 28767, increased the basal cAMP level and inhibited the forskolin-induced increase in the cAMP level in EP3 gamma, while it decreased both the basal and forskolin-elevated cAMP levels in EP3 alpha and EP3 beta. The M&B 28767-stimulated GTPase activity consisted of pertussis-toxin-sensitive and cholera-toxin-sensitive portions in the EP3 gamma-expressing cell membrane, suggested that EP3 gamma is coupled to both guanine nucleotide-binding inhibitory and stimulatory proteins. These results indicate that EP3 gamma is coupled to both stimulation and inhibition of adenylate cyclase, but that EP3 alpha and EP3 beta are exclusively coupled to inhibition of adenylate cyclase. Thus, alternative splicing produces a third isoform with a different carboxy-terminal tail, which differs from the other two isoforms in the specificity of coupling to a signal-transduction pathway.

Adenylyl Cyclase Inhibitors↗
PubMed1993

Cloning and expression of cDNA for a mouse EP1 subtype of prostaglandin E receptor.

A functional cDNA clone encoding a mouse EP1 subtype of prostaglandin (PG) E receptor was isolated from a mouse cDNA library by cross-hybridization with the mouse thromboxane A2 receptor cDNA. The clone isolated encodes a protein consisting of 405 amino acid residues with putative seven-transmembrane domains. [3H]PGE2 specifically bound to the membrane of Chinese hamster ovary cells expressing this clone. The binding to the membrane was displaced with unlabeled PGs in the order of PGE2 > iloprost (a prostacyclin analogue) > PGE1 > PGF2 alpha > U-46619 (a thromboxane A2 analogue) > PGD2. The binding was also inhibited by 17-phenyl trinor PGE2 (an EP1 agonist) and sulprostone (an EP1 and EP3 agonist) but not by 11-deoxy PGE1 (an EP2 and EP3 agonist) and butaprost (an EP2 agonist). PGE2 induced a rapid increase in intracellular Ca2+ concentration in Chinese hamster ovary cells expressing the receptor. These results suggest that this receptor belongs to EP1 subtype of PGE receptor. Northern blot analysis demonstrated that the mRNA of this receptor is expressed abundantly in kidney and in a lessor amount in lung.

Amino Acid Sequence↗