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Noboru Kitamura

Publications and source records attributed to Noboru Kitamura.

44 records · Page 3Linked to original sources
PubMed2002

A mechanistic study of photocyanation of pyrene in oil-in-water emulsion systems.

A highly efficient one-step photocyanation reaction of pyrene was shown to proceed in oil-in-water emulsion systems. As a typical example, photoirradiation of pyrene in the presence of 1,4-dicyanobenzene and NaCN in a benzonitrile/water mixture (1/100, vol %) under vigorous stirring gave 1-cyanopyrene in a conversion yield of 83%, while an analogous reaction in an acetonitrile/water mixture (9/1, vol %) yielded this product in 61% yield. We evaluated the quantum yield of photocyanation in the oil-in-water emulsion system to be 0.17. Under optimum conditions, the quantum yield was improved to 0.68. Characteristics and possible mechanisms of the photocyanation reaction are discussed in detail.

Journal Article↗
PubMed2002

Chemical responses of single yeast cells studied by fluorescence microspectroscopy under solution-flow conditions.

A microspectroscopy system combined with a fluid manifold was developed to manipulate and analyze "single" living cells. A sample buffer solution containing living cells was introduced into a flow cell set on a thermostated microscope stage and a few cells were allowed to attach to the bottom wall of the flow cell. With these living cells being attached to the wall, other floating cells were pumped out by flowing a buffer solution. These procedures made it possible to keep a few cells in the flow cell and to analyze single cells by fluorescence microspectroscopy. The technique was applied to study the time course of staining processes of single living yeast (Saccharomyces cerevisiae) cells by using two types of a fluorescent probe. The present methodology was shown to be of primary importance for obtaining biochemical/physiological information on single living cells and also for studying cell-to-cell variations in several characteristics.

Flow Cytometry↗
PubMed2002

Selective reduction of a PDZ protein, SAP-97, in the prefrontal cortex of patients with chronic schizophrenia.

Many postsynaptic density proteins carrying postsynaptic density-95/discs large/zone occludens-1 (PDZ) domain(s) interact with glutamate receptors to control receptor dynamics and synaptic plasticity. Here we examined the expression of PDZ proteins, synapse-associated protein (SAP) 97, postsynaptic density (PSD)-95, chapsyn-110, GRIP1 and SAP102, in post-mortem brains of schizophrenic patients and control subjects, and evaluated their contribution to schizophrenic pathology. Among these PDZ proteins, SAP97 exhibited the most marked change: SAP97 protein levels were decreased to less than half that of the control levels specifically in the prefrontal cortex of schizophrenic patients. In parallel, its binding partner, GluR1, similarly decreased in the same brain region. The correlation between SAP97 and GluR1 levels in control subjects was, however, altered in schizophrenic patients. SAP102 levels were also significantly reduced in the hippocampus of schizophrenic patients, but this reduction was correlated with sample storage time and post-mortem interval. There were no changes in the levels of the other PDZ proteins in any of the regions examined. In addition, neuroleptic treatment failed to mimic the SAP97 change. These findings suggest that a phenotypic loss of SAP97 is associated with the postsynaptic impairment in prefrontal excitatory circuits of schizophrenic patients.

Adaptor Proteins, Signal Transducing↗
PubMed2002

Photochemical ion receptor based on a structurally distorted ruthenium(II) complex having a crown-ether moiety at the 3,3'-positions on the 2,2'-bipyridine ligand.

Ru(bpy)2(CE-bpy)2+ was prepared where bpy and CE-bpy were 2,2'-bipyridine and bpy having a crown-ether moiety at the 3,3'-positions, respectively. Although Ru(bpy)2(CE-bpy)2+ showed only very weak emission in acetonitrile, recognition of Na+, Li+, or K+ by the crown-ether moiety in CE-bpy resulted in increases in both the emission intensity and the lifetime of the complex, demonstrating that it acted as a photoreceptor. The results were discussed in terms of a steric hindrance between the 3,3'-substituents on CE-bpy and structural changes in both CE-bpy and the complex upon ion recognition, as studied by variable-temperature 1H-NMR and steady-state/dynamic emission spectroscopy of the complex.

Journal Article↗
PubMed2001

Chelate Formation around a Hexarhenium Cluster Core by the Diphosphane Ligand Ph(2)P(CH(2))(6)PPh(2) This work was supported in part by Grant-in-Aid for Scientific Research No. 10149102 (Priority Area of "Metal-Assembled Complexes") from the Ministry of Education, Science, Sports, and Culture of Japan. Z.-N.C. is grateful to JSPS for a postdoctoral fellowship. The authors are grateful to Prof. C. Schäffer (University of Copenhagen) for his help in revising the manuscript.

Explore the source record for details and available documents.

Journal Article↗
PubMed1999

Differential changes in glutamatergic transmission via N-methyl-D-aspartate receptors in the hippocampus and striatum of rats behaviourally sensitized to methamphetamine.

We searched for changes in glutamatergic transmission via N-methyl-D-aspartate (NMDA) receptors in the hippocampus and striatum of rats behaviourally sensitized to methamphetamine (Meth). Prior to being given a challenge dose of Meth (2 mg/kg, s.c.), the rats were given Meth (4 mg/kg, s.c.) five times a week for 3 wk. Seven days after the challenge test, we examined glutamate (Glu) release from hippocampal and striatal slices evoked by 30 mm KCl, and NMDA-evoked dopamine (DA) release from striatal slices. We further immunoquantified NMDAR1, R2A and R2B receptors as well as the fodrin alpha-subunit, a 240 kDa cytoskeletal protein that is cleaved to form 150 kDa limited proteolytic fragments by NMDA receptor stimulation. In the study of KCl-evoked Glu release, Glu release from the hippocampus was 31% lower in the Meth-sensitized rats than in the control rats, while Glu release from the striatum was 34% higher in the Meth-sensitized rats. NMDAR1, R2A and R2B immunoreactivities in the striatum were significantly lower in the Meth-sensitized rats (by 12, 13 and 12%, respectively) than those in the control rats. However, no differences in the immunoreactivities were found for the hippocampus. Immunoquantification of the fodrin alpha-subunit in the hippocampus revealed that 150 kDa fragments were significantly lower (by 10%) in the Meth-sensitized rats than in the control rats. In contrast to the control rats, NMDA-evoked DA release from the striatum was diminished in the Meth-sensitized rats. These results indicate that the activity of the Glu system is functionally decreased in the hippocampus of Meth-sensitized rats, whereas the Glu system in the striatum of Meth- sensitized rats shows adaptive and functional changes in the receptors in response to the increased Glu release.

Journal Article↗