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Biomedical subjects

M Sekine

Publications and source records attributed to M Sekine.

At least 109 records · Page 6Linked to original sources
PubMed1994

A cis-acting element and a trans-acting factor involved in the wound-induced expression of a horseradish peroxidase gene.

The mechanisms that control the wound-induced expression of the prxC2 gene for horseradish peroxidase (HRP) have been investigated. Analysis of the regulatory properties of 5'-deleted promoters showed that a positive element involved in the response to wounding was located between -307 and -99 bp from the site of initiation of translation. In in vitro binding assays of tobacco nuclear proteins and DNA fragments of prxC2 promoter, the binding site was the Box 1 from -296 to -283 containing the CACGTG motif. To identify the functional role of Box 1, the prxC2 promoter that has been digested from the 5' end to -289 with a disrupted Box 1 was fused to a reporter gene for beta-glucuronidase (GUS). No induction of GUS activity was observed in transgenic tobacco plants with the prxC2 (-289)/GUS construct. These data indicated that the expression of prxC2 in response to wounding required the Box 1 sequence from -296 to -283. Furthermore, a tobacco cDNA expression library was screened and a cDNA clone for a protein, designated TFHP-1, that bound specifically to the Box 1 sequence was identified. The putative TFHP-1 protein contains a basic region and leucine zipper (bZip) motif and a helix-loop-helix (HLH) motif. The mRNA for TFHP-1 was abundant in roots and stems, and it was not induced by wounding in leaves. In tobacco protoplasts, antisense TFHP-1 suppressed the expression of prxC2(-529)/GUS.

Amino Acid Sequence↗
PubMed1994

[A case of inflammatory breast cancer successfully treated with 5'-DFUR and MPA].

A 67-year-old female with extensive inflammatory breast cancer was treated with oral chemoendocrine therapy using 5'-deoxy-5-fluorouridine (5'-DFUR) 1,200 mg and medroxyprogesterone acetate (MPA) 1,200 mg before intra-arterial infusion chemotherapy, which made the extensive inflammatory skin lesion improve remarkably. Sequential intra-arterial infusion made the skin lesion completely disappear. But the main tumor remained, so extended mastectomy was performed. These findings suggested that this therapy was effective for the prevention of extension of the skin lesion on the inflammatory breast cancer, and also served as induction therapy for this modality.

Administration, Oral↗
PubMed1994

[Study on risk factors for progression of visual field damage in normal-tension glaucoma].

We investigated the risk factors for progression of visual field damage in normal-tension glaucoma (NTG), using multiple regression analysis with the proportional hazard model and the life-table method. Seventy-six eyes of 56 patients with untreated NTG showing minor visual-field defects, with a mean deviation (MD) of > - 5 dB by the Humphrey (30-2) STATPAC program at entry, were included in the study. Endpoints of study follow-up were defined as follows: in HFA STATPAC 2 Glaucoma Change Probability Analysis, more than 5 points which significantly deteriorated at p < 0.05 were found at 2 consequent examinations (Criterion 1) or a significant decrease in the MD value at p < 0.025 was encountered at one examination or that at p < 0.05 at 2 consecutive examinations (Criterion 2). During the follow-up period (37 months, mean), 33 eyes (42%) satisfied Criterion 1 and 23 eyes (29%) Criterion 2. When Criterion 1 was employed, peripapillary chorio-retinal atrophy/disc ratio (p = 0.023), intraocular pressure (IOP) (p = 0.03) and cup/disc ratio (p = 0.035) were identified as significant risk factors for progression of visual-field damage. When Criterion 2 was employed, Contribution of cup/disc ratio (p = 0.065) and IOP (p = 0.145) was relatively high, but not significant. These results suggested an association of IOP and local vascular risk factors with progression of visual-field damage in NTG.

Female↗
PubMed1993

[Radiotherapy for symptomatic osseous metastases: special reference to the analysis of patients achieved complete pain relief].

A total of 223 patients with 498 symptomatic osseous metastases treated by radiotherapy between July 1985 and June 1991 were retrospectively analyzed. Most sites, 409 (82%), were irradiated by conventional fractionation, while the remaining 89 sites were irradiated by dose-increment fractionation, low-dose short schedules or hyperfractionation. The total dose ranged from 5.4 to 74 Gy (mean, 41.4 Gy). Daily pain assessment was done by patients themselves on an 11-point scale, i.e., 10: pretreatment pain, 0: disappearance of pain following radiotherapy. In addition, improvement in performance status (PS) and the duration of complete pain relief were assessed. The following results were obtained. 1) Pain relief: Of 498 evaluated sites, complete pain relief and partial pain relief were achieved in 403 sites (81%) and 64 sites (13%), respectively. No significant difference was seen in the incidence of complete pain relief between weight-bearing bone and non-weight-bearing bone. Patients with PS 1, 2 or 3 were significantly superior to those with PS 4 in terms of complete pain relief (P < 0.05-0.001). The complete response rate increased in accordance with the dose delivered, i.e., 49% at 20 Gy, 70% at 30 Gy and 77% at 40 Gy, in all of the 498 sites irradiated; 60%, 86% and 95% of 403 sites, respectively, achieved complete pain relief. Regarding the fractionation regimens, dose-increment fractionation was superior to both conventional fractionation and low-dose short schedules in terms of complete pain relief rate. 2) Improvement of PS: Of 223 evaluated patients, PS was improved 1 to 3 steps in 162 (73%) at the completion of radiotherapy. The improvement rates of patients with PS 2 or 3 were significantly better than those with PS 4 (P < 0.025, 0.001). 3) Duration of complete pain relief: Of 288 appraisable sites, the recurrence of pain was recognized in 23 (9%) at intervals of 3 to 21 months (median, 5 months). On the other hand, the duration of pain relief was 16 to 79 months (median, 32 months) in 26 sites of survivors, and 1 to 28 months (median, 5 months) in 239 sites of decreased patients. The mean total dose was 48.5 Gy (TDF: 82) to 62 sites with a duration of pain relief of more than 13 months. 4) Re-irradiation to the same site: Of 14 sites retreated after initial complete response with a total dose of 30 to 50 Gy (mean, 48 Gy), 11 (79%) were in weight-bearing bone and 9 (64%) responded completely. 5) Patients with unsatisfactory pain relief (pain score > or = 6): Of 31 sites, 27 (94%) were in patients with PS 4, and 19 (61%) received a total dose below 30 Gy. 6) The 11-point scale for patient self-assessment of pain relief following radiotherapy was thought to be useful and easy to adopt in general clinics.

Adolescent↗
PubMed1993

Purification and characterization of UDP-N-acetylgalactosamine GM3/GD3 N-acetylgalactosaminyltransferase from mouse liver.

A UDP-N-acetylgalactosamine: Sia alpha 2-3Gal beta 1-4Glc beta 1-/Sia alpha 2-8Sia alpha 2-3Gal beta 1-4Glc beta 1-1ceramide N-acetylgalactosaminyltransferase has been purified to apparent homogeneity from mouse liver. The purification procedure involved differential centrifugation for preparation of Golgi membranes, extraction of the enzyme with Triton X-100, and sequential chromatography on phosphocellulose, UDP-aldehyde adipic acid hydrazone agarose, UDP-hexanolamine-Sepharose, CM-Sepharose, and DEAE-Sepharose. At the phosphocellulose column chromatography step, the recovery of the enzyme activity was less than 25%, but it was enhanced up to 70% when the enzyme assay was performed in the presence of the flow-through fraction from the phosphocellulose column. With this assay, the enzyme activity was found to be quantitatively recovered during all the column chromatographies, the enzyme finally being purified 171,000-fold with a specific activity of 3.6 mumol/min/mg protein. The apparent molecular mass of the purified enzyme is 65,000 daltons. The enzyme exhibits a pH optimum of 7.5-7.9 and requires 2.5-10 mM Mn2+ for the maximal activity. The Km value for UDP-N-acetylgalactosamine is 7 microM. Among the glycolipids tested as acceptor substrates, NeuGc alpha 2-3Gal beta 1-4Glc beta 1-1ceramide, NeuAc alpha 2-3 Gal beta 1-4Glc beta 1-1ceramide, NeuGc alpha 2-8NeuGc alpha 2-3Gal beta 1-4Glc beta 1-1ceramide, and NeuAc alpha 2-8NeuAc alpha 2-3Gal beta 1-4Glc beta 1-1ceramide are good ones, the Km values for them being 160, 2,100, 27, and 350 microM, respectively, but sialyllactose, NeuAc alpha 2-3Gal beta 1-4Glc, is not. This suggests that the enzyme recognizes not only the oligosaccharide portion but also the ceramide of gangliosides.

Animals↗
PubMed1993

A modified uridine in the first position of the anticodon of a minor species of arginine tRNA, the argU gene product, from Escherichia coli.

The argU (dnaY) gene product, a minor tRNA(Arg), from Escherichia coli has the anticodon N*CU with an unidentified modified nucleoside N* in position 34 [Kiesewetter, S., Fisher, W. & Sprinzl, M. (1987) Nucleic Acids Res. 15, 3184]. In the present study, argU tRNA was purified from E. coli A19 strain and nucleoside N* was characterized by the TLC and HPLC analyses. Nucleoside N* was found to be different from any naturally occurring modified nucleosides. From unfractionated E. coli tRNA species, nucleoside N* was prepared in an amount sufficient for 1H-NMR experiments. By the analyses of one-dimensional and two-dimensional NMR spectra, nucleoside N* was suggested to be 5-methylaminomethyluridine (mnm5U), which was confirmed by comparison with a chemically synthesized preparation of mnm5U. Thus, the occurrence of mnm5U in mature tRNA was found for the first time. Further, the modification of U(34) to mnm5U in this tRNA was found to contribute to the strict recognition of two degenerate codons terminating in A and G.

Anticodon↗
PubMed1993

Nucleo-cytoplasmic transport of U snRNPs: definition of a nuclear location signal in the Sm core domain that binds a transport receptor independently of the m3G cap.

We have investigated the nuclear transport of U1 and U5 snRNPs by microinjection studies in oocytes from Xenopus laevis using snRNP particles prepared by reconstitution in vitro. Competition studies with snRNPs showed that the Sm core domain of U1 snRNPs contains a nuclear location signal that acts independently of the m3G cap. The transport of U1 snRNP can be blocked by saturation with competitor U1 snRNPs or by U5 snRNPs, which indicates that the signals on the respective Sm core domains interact with the same transport receptors. Further, by using a minimal U1 snRNP particle reconstituted in vitro and containing only the Sm core RNP domain and lacking stem-loops I to III of U1 RNA, we show that this is targeted actively to the nucleus, in spite of the absence of the m3G cap. This indicates that under certain conditions the NLS in the Sm core domain not only is an essential, but may also be a sufficient condition for nuclear targeting. We propose that the RNA structure of a given snRNP particle determines at least in part whether the particle's m3G cap is required for nuclear transport or can be dispensed with.

Animals↗
PubMed1993

New strategies for oligonucleotide synthesis by use of 2-trimethylsilylethyl and 2-trimethylsilylethoxymethyl as the phosphate and 2'-hydroxyl protecting groups, respectively.

The 2-Trimethylsilylethyl (TSE) group was found to be useful as a protecting group for the internucleotidic phosphate in DNA synthesis. Oligodeoxyribonucleotides were synthesized in good yields by using phosphoramidite building blocks having the TSE group. In RNA synthesis, 2-trimethylsilylethoxymethyl (SEM) group was introduced as a new protecting group for the 2'-hydroxyl. Selective protection of this function with SEM-Cl was achieved in good yield by use of 3',5'-O-bis(tert-butyl)silanediyl ribonucleoside derivatives.

Hydroxylation↗
PubMed1992

Molecular design of a eukaryotic messenger RNA and its chemical synthesis.

A designed mRNA consisting of 42 ribonucleotides having the cap structure was synthesized. The capped leader sequence of the brome mosaic virus (BMV) mRNA 4, m7G5'pppGUAUUAAUA (F-1), was synthesized by the phosphotriester method and followed by the capping reaction. A 32-mer consisting of an initiation codon (AUG), the coding region corresponding to a bacterial pheromone cAD1 and two stop codons, was constructed by the 18-mer (F-2) and 14-mer (F-3), which were synthesized by the phosphoramidite method. 2'-,3'-O-Methoxymethylene-guanosine 5'-phosphate was condensed with F-3 using P1-2',3'-O-methoxymethyleneguanosine-5'-yl P2-adenosine-5'-yl pyrophosphate (9) with T4 RNA ligase. The chemically synthesized RNA fragments were ligated successively with T4 RNa ligase to afford the whole RNA molecule.

Amino Acid Sequence↗
PubMed1992

Conformational rigidity of specific pyrimidine residues in tRNA arises from posttranscriptional modifications that enhance steric interaction between the base and the 2'-hydroxyl group.

In order to elucidate roles of the 2'-O-methylation of pyrimidine nucleotide residues of tRNAs, conformations of 2'-O-methyluridylyl(3'----5')uridine (UmpU), 2'-O-methyluridine 3'-monophosphate (Ump), and 2'-O-methyluridine (Um) in 2H2O solution were analyzed by one- and two-dimensional proton NMR spectroscopy and compared with those of related nucleotides and nucleoside. As for UpU and UmpU, the 2'-O-methylation was found to stabilize the C3'-endo form of the 3'-nucleotidyl unit (Up-/Ump-moiety). This stabilization of the C3'-endo form is primarily due to an intraresidue effect, since the conformation of the 5'-nucleotidyl unit (-pU moiety) was only slightly affected by the 2'-O-methylation of the 3'-nucleotide unit. In fact even for Up and Ump, the 2'-O-methylation significantly stabilizes the C3'-endo form by 0.8 kcal/.mol-1. By contrast, for nucleosides (U and Um), the C3'-endo form is slightly stabilized by 0.1 kcal/.mol-1. Accordingly, the stabilization of the C3'-endo form by the 2'-O-methylation is primarily due to the steric repulsion among the 2-carbonyl group, the 2'-O-methyl group and the 3'-phosphate group in the C2'-endo form. For some tRNA species, 2-thiolation of pyrimidine residues is found in positions where the 2'-O-methylation is found for other tRNA species.(ABSTRACT TRUNCATED AT 250 WORDS)

Dinucleoside Phosphates↗
PubMed1992

[The existence of vasomotor nerve in the retina of the rabbit and monkey].

In the first stage of this study, peri- or intravascular unmyelinated nerve axon which was clearly different from that of the optic nerve was confirmed in the rabbit retina transmission electron microscopically. In the second stage, the correlation of these unmyelinated nerves and autonomic nerve was studied in rabbits and monkeys. For the purpose, wheat germ agglutinin horseradish peroxidase (WGA-HRP) was injected into the superior cervical ganglion. Electron microscopic observation of the retina 48 hrs after the injection of WGA-HRP showed deposit of its reaction product in the axon of the unmyelinated nerve located around the vascular wall and in the adventitia and smooth muscle cell in both rabbits and monkeys. This result clearly reveals the existence of an autonomic vasomotor in the retinal vessels at least in rabbits and monkeys.

Animals↗
PubMed1991

Two pathways for GM2(NeuGc) expression in mice: genetic analysis.

We have reported that WHT/Ht mice express neither GM2(NeuGc) nor GM1(NeuGc) in the liver or erythrocytes due to a defect on the Ggm-2 gene, which was demonstrated to control the activity of UDP-GalNAc:GM3(NeuGc) N-acetylgalactosaminyltransferase in mouse liver, and, in addition, WHT/Ht mice do not express a detectable amount of GM2(NeuGc) but do express GM1(NeuGc) in tissues other than the liver and erythrocytes, such as the spleen, thymus, heart, lung, kidney, and testis [Nakamura et al. (1988) J. Biochem. 103, 201-208]. In order to determine whether the phenotype of WHT/Ht mice exhibiting an undetectable amount of GM2(NeuGc) in these tissues is genetically controlled or not, we analyzed the expression of gangliosides in the progeny obtained on backcross mating between (BALB/c X WHT/Ht)F1 and WHT/Ht mice, and in a GM2(NeuGc) congenic mouse, WHT.C. Concerning the expression of GM2(NeuGc) in the liver, lung, and kidney, 102 backcross mice could be segregated into two types. One type expressed a detectable amount of GM2(NeuGc) in the liver, lung, and kidney, and the other type did not. The ratio of the numbers of mice exhibiting these two types was 42: 60, indicating that the two phenotypes were genetically determined by the involvement of a single autosomal gene. Recombination as to GM2(NeuGc) expression in the liver, lung, and kidney was not detected among the 102 backcross mice. Analysis of the GM2(NeuGc) congenic mouse indicated that a detectable amount of GM2(NeuGc) was expressed in the liver, erythrocytes, lung, kidney, heart, spleen, and small intestine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Chemical synthesis of branched RNAs: a new method for construction of synthetic units for branched RNAs by use of 2'-phosphorylation on the basis of steric control.

A 3',5'-unprotected 2'-O-bis(tert-butoxy)-phosphinyl-6-N-benzoyladenosine derivative was prepared as a key intermediate for the synthesis of branched RNAs, and used for construction of building units from which chain elongation in any of 2'-, 3'-, and 5'-directions would be possible. From this synthetic intermediate, 2'-phosphorylated ApC dimer was also synthesized.

Base Sequence↗
PubMed1990

The expression of IV6 beta[Gal beta 1-4(Fuc alpha 1-3)GlcNAc]-Gb5Cer in mouse kidney is controlled by the Gsl-5 gene through regulation of UDP-GlcNAc:Gb5Cer beta 1-6N-acetylglucosaminyltransferase activity.

We reported the polymorphic expression of GL-Y (IV6 beta[Gal beta 1-4(Fuc alpha 1-3)GlcNAc]-Gb5Cer in kidneys of inbred strains of mice in previous papers [J. Biochem. 101, 553-562 and 563-568 (1987)]. DBA/2 mice express a large amount of GL-X (Gb5Cer), but not GL-Y, in their kidneys, because of a defect on a single autosomal gene (Gsl-5). This suggested that DBA/2 mice lack the ability to transfer GlcNAc onto the C-6 position of GalNAc of Gb5Cer or GL-X. In this study, we characterized UDP-GlcNAc:GL-X beta 1-6N-acetylglucosaminyltransferase (beta 1-6GlcNAc transferase) in the microsomal fraction of mouse kidney. Maximum activity was detected with an incubation mixture containing sodium cacodylate buffer (pH 6.4), 0.1% Zwittergent 3-16 and 1 mM EDTA. Divalent cations were not required. The apparent Km values for UDP-GlcNAc and GL-X were 0.42 and 0.12 mM, respectively. The product of the enzymatic reaction was identified as IV6 beta GlcNAc-Gb5Cer by means of 1H-NMR spectroscopy and permethylation analyses. Then, we measured the beta 1-6GlcNAc transferase activity in the microsomal fractions of kidneys of inbred strains of mice and progeny obtained on mating. WHT/Ht, C57BL/10, BALB/c, and C3H/He mice, which express GL-Y in their kidneys, exhibited detectable amounts of activity, whereas CBA and DBA/2 mice, which do not express GL-Y, did not exhibit detectable activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Synthesis of RNA having cap structure.

RNA consisting 43 nucleotides bearing cap structure was synthesized (Figure). In the first place, 9 mer of a leader sequence with the cap structure (F-1) was synthesized by the phosphotriester method and followed by the capping reaction. Next, 32 mer of a cistron was divided into two fragments and each was synthesized by the phosphoramidite method. The 3'-end nucleotide of the RNA, a modified guanosine 5'-phosphate, was introduced to F-3 by use of P1-2',3'-O-methoxymethylene guanosine-5'-yl P2-adenosine-5'-yl diphosphate (A5' ppGmM) with T4 RNA ligase. The chemically synthesized RNA fragments were ligated with T4 RNA ligase to afford the desired RNA.

Amino Acid Sequence↗
PubMed1990

Chemical synthesis of the 5'-terminal structure of U1 RNA.

A new method for the synthesis of N2,N2-dimethylguanosine (DMG) is developed by reductive C-S bond cleavage by use of tributyltin hydride. An improved method for the synthesis of the key intermediate (1) for construction of the 5'-terminal structure of U1 RNA, which has a trimethylated cap (TMG) structure at its 5' end, is also described. By the use of 1, several TMG-capped ribonucleosides and oligonucleotides were synthesized.

Guanosine↗