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Biomedical subjects

T Miyake

Publications and source records attributed to T Miyake.

At least 451 records · Page 25Linked to original sources
PubMed1980

Solid-phase synthesis of polynucleotides. II. Synthesis of polythymidylic acids by the block coupling phosphotriester method.

Synthesis of two oligothymidylic acids, tridecamer and nonadecamer, is described by a rapid and simple solid-phase method on two kinds of polyacrylamide supports derivatized from commercially available Enzacryl Gel K-2. The syntheses were performed by the phosphotriester method using di- and tri-thymidylic acid blocks as the incoming 3'-phosphodiester component. High coupling yields were consistently obtained and the final product was isolated very easily by high performance liquid chromatography on Permaphase AAX.

Indicators and Reagents↗
PubMed1980

Elongation of oligonucleotides in the 3'-direction with activated mononucleotides and their analogs using RNA ligase.

P1-Adenosine 5'-P2-2',3'-ethoxymethylidene nucleosides [A(5')ppN(Em)] from four common nucleosides have been prepared and used for single addition of nucleotides to elongate oligonucleotide chains in the 3'-direction in RNA ligase reaction. U-U-C, T-U-C and A-C-C were used as acceptors. Structural dependence in these acceptors was found to be smaller compared to joining reactions between oligonucleotides. Adenosine analogs including 8-bromo-, 2'-fluoro-, 2'-azido-, 8,2'-O-cyclo-, 8,2'-S-cyclo-adenosine, arabinosyladenine and 2'-deoxyadenosine were added to the 3'-end of A-C-C by adenylation chemically followed by joining with RNA ligase. Symmetrical 5'-pyrophosphates of 8-bromo-, 2'-fluoro- and 2'-azido-adenosine were not recognized as donor substrates.

Adenine Nucleotides↗
PubMed1980

Endoscopic evaluation of the effect of sucralfate therapy and other clinical parameters on the recurrence rate of gastric ulcers.

A randomized controlled clinical study was conducted to determine (a) whether basic aluminum sucrose sulfate (sucralfate) is effective in preventing or reducing gastric ulcer recurrence, and (b) the clinical parameters contributing to ulcer recurrence after endoscopically proved healing has been effected. A total of 167 patients were assigned on a random basis to either of two treatment groups, control (aluminum hydroxide and magnesium oxide) or sucralfate, and given these medications for 6 months. At the end of this period all medication was withdrawn from both groups and the patients were followed for an additional 12 months. Each patient was examined endoscopically at bimonthly intervals throughout the 18-month observation period. Treatment (sucralfate), ulcer history, size of previous ulcer(s), prestudy healing time, and prestudy healing stage attained (red or white scarring) were associated with a significant reduction in recurrence rate. Ulcer recurrence was markedly reduced in sucralfate patients as compared to control when the pretreatment ulcers had healed slowly (P less than 0.001).

Adult↗
PubMed1980

Correlation of gastric ulcer healing features by endoscopy, stereoscopic microscopy, and histology, and a reclassification of the epithelial regenerative process.

Four stages of gastric ulcer healing have been established by correlating endoscopic findings with those obtained from stereoscopic microscopy and histologic observations: I. initial healing stage; II. proliferative healing stage; III. palisade scar stage; IV. cobblestone scar stage. The palisade scar and cobble stone scar stages roughly correspond to Sakita's red and white scar stages, respectively. It is suggested that healing is not complete until the cobblestone stage with attendant micropit formation is achieved.

Endoscopy↗
PubMed1980

New device for the measurement of hydrogen clearance rate from the gastric mucosa.

The hydrogen clearance rate of the nucosa of the glandular stomach of the anesthetized rat was obtained with the platinum electrode in contact with the surface of the gastric mucosa (Contact Electrode Method). By using two indicator electrodes, the gastric blood flow was measured simultaneously with one electrode in contact with the mucosal surface (Contact Electrode Method), and with the other electrode inserted into the gastric wall (Inserted Electrode Method). Pentagastrin produced increase in blood flow by both contact and inserted electrode methods. Isoproterenol stimulated blood flow as determined by the contact electrode method, but when the flow was determined by the inserted electrode method it reduced the blood flow. The combination of these two methods is useful in the determination of the blood flow in the different layers of the stomach.

Animals↗
PubMed1980

Thrombopoiesis and megakaryocyte colony stimulating factor in the urine of patients with aplastic anaemia.

The urinary extracts from patients with aplastic anaemia and from healthy donors were investigated in vivo and in vitro for their ability to stimulate megakaryopoiesis and platelet production. There was a significantly higher concentration of thrombopoiesis stimulating factor (TSF) and megakaryocyte colony stimulating factor (MEG-CSF) in the urine from patients with aplastic anaemia than in that from healthy donors. Neuraminidase treatment did not affect the thrombopoietic activity of TSF, whereas coexisting erythropoietin (EPO) in the extract lost in its activity in vivo. These findings suggest that TSF and/or MEG-CSF seems to be different from EPO and that the urine from aplastic anaemia patients would be a good source of TSF and MEG-CSF for purification and characterization.

Anemia, Aplastic↗
PubMed1980

Synthesis of 5' fragments of formylmethionine transfer ribonucleic acid and their reconstitution with a natural three-quarter molecule.

An eicosanucleotide C--G--C--G--G--G--G--U--G--G--A--G--C--A--G--C--C--U--G--Gp corresponding to the bases 1--20 of the nascent sequence for the Escherichia coli tRNAfMet has been synthesized by the joining of the chemically synthesized oligonucleotides C--G--C--G, G--G--G--U--G--G and A--G--C--A--G--C--C--U--G--Gp using RNA ligase from T4-infected E. coli. The hexanucleotide and decanucleotide were phosphorylated with polynucleotide kinase and [gamma-32P]ATP prior to the joining reactions. The decanucleotide and eicosanucleotide were reconstituted respectively with the 3'-three-quarter molecule obtained by limited digestion with RNase T1 of the natural tRNAfMet from E. coli and the activity of the complex as a methionine acceptor was tested using purified methionyl-tRNA synthetase from E. coli. The amino acid acceptor activity of the reconstituted molecules was 11% and 84% with respect to that of the intact tRNAfMet.

Base Sequence↗
PubMed1980

Hemoglobin takamatsu (beta 120 (GH 3) Lys leads to Gln): a new abnormal hemoglobin detected in three unrelated families in the takamatsu area of shikoku.

A survey of hemoglobinopathies which was carried out in the Takamatsu district during the period from January to August 1979 detected six families with abnormal hemoglobins. Approximately 6010 inhabitants were screened. Three of these families had the same new Hb variant (Hb Takamatsu beta 120 Lys leads to Gln) that has not been previously reported. Existence of a blood relationship among these three families could not be established even after careful family studies. This abnormal hemoglobin was not associated with adverse symptoms and gave normal hematologic findings in the carriers. The isopropranol test was negative, oxygen affinity was within the normal range, and biosynthetic ratio in reticulocytes was around 1.0. One of the difficulties in the structural analysis of this hemoglobin was related to complete superposition of abnormal beta XT-12b,13 on a beta T-8,9 peptide in the fingerprint of the trypsin digest of aminoethylated aberrant beta X chain. This was overcome by collection of abnormal tryptic beta core (beta XT-10-13) from unmodified beta X chain, and subsequent digestion by chymotrypsin. Edman analysis of the chymotryptic peptides thus obtained successfully confirmed the substitution to be beta 120 Lys leads to Gln.

Adult↗
PubMed1980

Total synthesis of tRNAfMet.

Oligonucleotides corresponding to the E. coli tRNAfMet fragments and their analogs have been synthesized by the phosphodiester or phosphotriester method. The nascent fragments were joined by using RNA ligase to yield a total tRNA molecule. The synthetic molecule was tested its ability to accept methionine in the presence of purified methionyl-tRNA synthetase from E. coli. The charged tRNA and the hydrolyzed methionine were isolated by gel filtration. The discharged tRNA was characterized by nearest neighbor analysis and 5'-end analysis.

Base Sequence↗