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Biomedical subjects

T Ueda

Publications and source records attributed to T Ueda.

At least 1,495 records · Page 83Linked to original sources
PubMed1980

Magnetic circular dichroism and circular dichroism of some nucleosides.

The magnetic circular dichroism and circular dichroism spectra of cytidine, isocytidine, 2,5'-O-cyclo-2',3'-O-isopropylidine uridine, and 2,2'-O-cyclouridine were measured in the wavenumber region of 30000 -50000 cm-1. On the basis of the experimental results, the tautomerism of cytidine and isocytidine was discussed. The transition energies, the oscillator strengths, and the Faraday parameters were calculated within the framework of the INDO approximation. The calculated results are in good agreement with the experimental results. And then the spectral assignment of the pyrimidin nucleosides, together with those of cytosine and isocytosine, were discussed on the basis of the experimental and theoretical results.

Circular Dichroism↗
PubMed1980

Introduction of substituents to the 7(8)-position of 7-deazaadenosine (tubercidin): conversion to toyocamycin.

Treatment of 2',3',5'-tri-O-acetyl-7-deazaadenosine with C1SCN gave the 7-thiocyanato derivative, which was converted to 7-methylthio and 7-methyl-sulfone derivatives. The thio-Claisen rearrangement and desulfurization of 7-allylthio derivative afforded 7-propyl-7-deazaadenosine. The 7-methylsulfone derivative gave the 8-cyano compound by treatment with NaCN. The action of nitrating agent on triacetyltubercidin gave a mixture of the 7- and 8-nitro derivatives. The Mannich reaction of tubercidin gave the 7-morpholinomethyl derivative which was converted to the methyl, formyl, hydroxymethyl, or cyano derivatives in good yield. The conversion of tubercidin to toyocamycin was thus accomplished. Some physical and biological properties of these substituted tubercidins were presented.

Indicators and Reagents↗
PubMed1980

Contraction rhythm in the plasmodium of Physarum polycephalum: dependence of the period on the amplitude, temperature and chemical environment.

The plasmodium of Physarum polycephalum exhibits a characteristic protoplasmic shuttle streaming and generates periodical tension. We determined the factors which govern the period of the contraction rhythm by measuring isometric tension of the plasmodial strand and the motive force of the protoplasmic streaming under a variety of conditions by changing the size of plasmodia, chemical composition of environment and surrounding temperatures. The results are: (1) The period of contraction rhythm, tau, increased linearly with the amplitude of oscillating tension, F, and was expressed by the following empirical equation when F was lower than a certain critical value, Fc, i.e., tau = aF+tau O. Above Fc, tau stayed at a constant level of tau S. There, a tau O and tau S are numerical constants which are independent of F. A similar relationship is valid for the amplitude of the motive force of the protoplasmic streaming, delta P. (2) Values of tau O were 1.0 min in air and 1.6 min in an aqueous medium and they were independent of temperature. (3) The Arrhenius plots of the parameter "a" exhibited different straight lines in air and in aqueous medium, from which the values of Q10 were determined to be 4.0 and 10, respectively. (4) Lowering of temperature decreased Fc, and eventually diminished it at Tc (= 15 degrees C). (5) The presence of glucose, CaCl2, MgCl2 and NaCl gave the identical tau-F relationship. Applications od D2O and ethanol slowed down the contraction rhythm, while that of KCl accelerated the rhythm. However, all these chemicals did not affect the tau O value. All results described above indicate that the contraction rhythm in the plasmodium is influenced by three components: a limit cycle which is independent of tension generation, a component which is strongly linked to the amplitude of the tension, F, and the part which is independent of the value of F. External factors appear to influence separately these three components of the contraction rhythm.

Cytoplasmic Streaming↗
PubMed1979

Widespread distribution of protein I in the central and peripheral nervous systems.

Protein I, a naturally occurring substrate for cyclic AMP-dependent and calcium-dependent protein kinases, previously has been found only in mammalian brain, where it has been demonstrated to be located in neurons. Various tissues and organs outside the brain have now been examined for the possible occurrence of protein I, by using both an immunohistochemical approach and a chemical procedure involving radioimmunolabeling of polyacrylamide gels. Protein I has been found in the inner plexiform layer of the retina, in the posterior pituitary, and in the autonomic nervous system. In tissue composed predominantly of cells other than nerve cells, immunoreactivity was present only where innervation was present. Protein I appeared to be localized in some, but not all, nerve terminals and synapses.

Animals↗
PubMed1979

Immunocytochemical localization, in synapses, of protein I, an endogenous substrate for protein kinases in mammalian brain.

Protein I is a principal endogenous substrate for cyclic AMP- and Ca2+-dependent protein kinases of mammalian brain. Antibodies raised against purified protein I have been used to localize this protein in the rat central nervous system. At the light microscope level, immunoreactivity was detected in punctate deposits in selected zones of synaptic termination. These deposits varied in density among brain regions. At the electron microscope level, immunoreactivity was observed at some but not all synaptic regions and was restricted to the perimeter of synaptic vesicles and to submembranous material in the postsynaptic neuron.

Animals↗
PubMed1979

Subcellular distribution in cerebral cortex of two proteins phosphorylated by a cAMP-dependent protein kinase.

The subcellular distribution of Proteins Ia and Ib, two proteins which serve as specific substrates for protein kinases present in mammalian brain, was studied in the dog cerebral cortex. Proteins Ia and Ib were found to be most highly enriched in synaptic vesicle fractions; they were also present in postsynaptic density and synaptic membrane fractions in significant amounts. Proteins Ia and Ib present in the synaptic vesicle fraction appear to be similar, if not identical, to those present in the postsynaptic density fraction as judged by several criteria: (a) the ability to serve as substrate for cAMP-dependent protein kinase, (b) electrophoretic mobility in the presence of sodium dodecyl sulfate, (c) extractability with NH4Cl or EGTA, and (d) fragmentation to electrophoretically similar peptides by a purified Staphylococcus aureus protease. In addition, the postsynaptic density fraction has been found to contain cAMP-dependent Protein Ia and Protein Ib kinase activity. The subcellular localization of Proteins Ia and Ib suggests a role for these proteins in the physiology of the synapse.

Animals↗
PubMed1979

Follow-up studies on the distribution of haemoglobin levels in female farm workers.

Haemoglobin concentrations in about 1000 women agricultural workers in Japan were measured every year, except in 1972, during the period 1967-77. Improvements were noted in the course of this investigation, and these were predominantly associated with the fact that those in the study community began to pay attention to the problem of low haemoglobin levels and to improve their diet, with an increase in daily food intake, particularly of animal protein and iron. In addition, a marked decrease in anaemia caused by hookworm also played an important role. In this paper, the change in haemoglobin concentration during the period of study are described and the aetiology is discussed.

Adult↗
PubMed1979

Simultaneous surgical treatment of tetralogy of Fallot and coronary artery aneurysm due to mucocutaneous lymph node syndrome in a 4-year-old child.

The simultaneous correction of tetralogy of Fallot and an aneurysm of the coronary artery due to mucocutaneous lymph node syndrome (MCLS) in a 4-year-old boy was successfully performed. Of the four aneurysms found on the coronary angiogram at the age of six months, the smaller three regressed spontaneously leaving slight dilatation and thickening of the arterial wall during the 4-year follow-up period. However, the largest one in the right coronary artery, which remained almost the same size, showed marked stagnation of blood in the aneurysm with the possibility of thrombosis and resultant myocardial infarction. At operation, there was a large aneurysm in the right coronary artery, 9 mm in width and 18 mm in length. The wall of the aneurysm was very thick and tightly adherent to the myocardium. The aneurysm was resected and an aorto-coronary bypass graft was fashioned from a saphenous vein taken from the patient's mother, since an autogenous vein was not available. A ventricular septal defect was closed and pulmonary stenosis was relieved without any difficulty. Postoperative cardiac catheterization and coronary angiography four weeks after the operation revealed satisfactory correction of the tetralogy of Fallot and a patent aorto-coronary vein graft. Several problems regarding surgical treatment of coronary artery aneurysm due to MCLS are discussed.

Adult↗
PubMed1979

The differences of the metabolism related to vitamin B6-dependent enzymes among vitamin B6-deficient germ-free and conventional rats.

The differences of the metabolism related to vitamin B6-dependent enzymes were investigated using germ-free and conventional rats. There was a significant difference in the boyd weight gain between vitamin B6-deficient germ-free and conventional rats after about 30 days of the experiment, and the body weight gain was much less in the deficient germ-free rats than in the deficient conventional ones. Urinary excretion of xanthurenic acid was higher in the deficient germ-free rats than in the deficient conventional ones after 18 days. There was a significant difference in the activities of kynurenine aminotransferase in mitochondrial fractions of germ-free rats, but not in mitochondrial fractions of conventional ones. The activities of aspartate and alanine aminotransferases, with or without pyridoxal phosphate, significantly decreased in the deficient germ-free rats, but not in the deficient conventional ones. These findings indicate that the degree of vitamin B6 deficiency was more severe in the deficient germ-free rats than in the deficient conventional ones, and also suggest that intestinal microflora may have some effects on vitamin B6-deficient conventional rats.

Alanine Transaminase↗