Biomedical subjects

M Nakaura

Publications and source records attributed to M Nakaura.

5 recordsLinked to original sources

PubMed2000

New perimetric threshold test algorithm with dynamic strategy and tendency oriented perimetry (TOP) in glaucomatous eyes.

PURPOSE: To investigate the time-wise reliability and efficiency of two new perimetric test algorithms, two computerised static threshold perimetry strategies, namely dynamic strategy (DS) and tendency oriented perimetry (TOP), were compared with the standard full-threshold strategy (normal strategy, NS). METHODS: We examined 41 eyes of 41 normal individuals without any ocular disease and 36 eyes of 36 glaucomatous patients, with the NS (4-to-2 dB), DS and TOP using an Octopus 1-2-3 perimeter. We analysed test time, stimulus time and the two global indices, mean sensitivity (MS) and loss variance (LV). Program 32X was used as test grid pattern. RESULTS: The mean test time for the NS was reduced by 52% with the DS and by 78% with the TOP strategy. Concerning the global indices, the MS value did not differ among the three strategies in the control or glaucoma group. However, the LV value was lower in the TOP strategy compared with the other two strategies in the glaucoma group. This suggested that the TOP strategy underestimated local glaucomatous visual field defects. The ability to detect early-stage glaucoma with the DS and TOP was inferior to that with the NS. CONCLUSIONS: The DS was more efficient than the TOP strategy for the detection of early glaucomatous defects, whereas the TOP strategy required less testing time. The TOP strategy may be an appropriate approach for patients in whom time-consuming perimetry is not possible, or in whom the visual field defect is already advanced.

Adult↗

PubMed1994

Sweetness of glycyrrhetic acid 3-O-beta-D-monoglucuronide and the related glycosides.

To improve the taste profile of glycyrrhizin (1, the saponin of licorice root, relative sweetness to sucrose: x170), a variety of 3-O-glycosides of glycyrrhetic acid were prepared and their sweetness evaluated. It was found that a significant enhancement of sweetness was observed for the 3-O-beta-D-xyloside and the 3-O-beta-D-glucuronide (MGGR). Especially, MGGR had a high sweetness relative to sucrose; x941, and would appear to be a new potent sweetener.

Carbohydrate Sequence↗

PubMed1991

Fluorescent-labeled oligonucleotide probes: detection of hybrid formation in solution by fluorescence polarization spectroscopy.

Fluorescein-labeled oligonucleotides as DNA-probes were synthesized and used to monitor hybrid formation, namely to detect DNA or oligonucleotide sequence in solution. The introduction of fluorescein to oligonucleotides was carried out by oxidation of a hydrogen phosphonate linkage with ethylenediamine or hexamethylenediamine as a tether and by a subsequent labeling of the primary amine moiety by FITC. Fluorescence anisotropy, r, was adopted as an index to monitor the behavior of F-probe in solution. An increase in the anisotropy was observed upon an increase in the chain-length of F-probe. When F-Probe formed a hybrid with its complementary oligonucleotide in solution, the r value increased compared to that of F-Probe itself. These observations clearly indicate that measurements of r in solution will readily lead to the monitoring of the presence of a hybrid in solution. Consequently, it is promising to detect a certain nucleic acid sequence in solution using fluorescent-labeled oligonucleotides.

Chromatography, High Pressure Liquid↗

PubMed1991

Further study on the 1,4-alpha-transglucosylation of rubusoside, a sweet steviol-bisglucoside from Rubus suavissimus.

Rubusoside (the beta-D-glucosyl ester of 13-O-beta-D-glucosyl-steviol), which is the major sweet principle of leaves of Rubus suavissimus S. Lee, was subjected to 1,4-alpha-transglucosylation by the cyclodextringlucanotransferase-starch system (the CGTase system). The tri- and tetra-glucosylated products were isolated together with the mono- and di-glucosylated products, which had already been isolated. A prominent increase in intensity of the sweetness was observed for the compounds which were di- and tri-glucosylated at the 13-O-glucosyl moiety. This result further substantiated the structure-sweetness relationship for 1,4-alpha-glucosylated compounds of steviol-glycosides reported previously. For protection of the 19-COO-glucosyl moiety against glucosylation by the CGTase system, the 4-hydroxyl group of the 19-COO-glucosyl moiety was beta-galactosylated by the beta-galactosidase-lactose system. This galactosylated compound was subjected to a regio-selective glucosylation of the 13-O-glucosyl moiety by the CGTase system, which was followed by enzymic elimination of the galactosyl group to furnish an exclusive preparation of the improved sweeteners just mentioned.

Carbohydrate Sequence↗

PubMed1990

Structural analysis of nucleic acids by labeled oligonucleotides.

In this report, the characterization of labeled oligonucleotides was discussed from the view points of base sequence analysis and structural analysis of nucleic acids in solution. Oligonucleotides site specifically spin labeled with TEMPO and fluorescent labeled with fluorescein were prepared and used for those analyses. The changes of ESR lines and rotational correlation time (tau) of the spin labeled oligonucleotide (S-probe) were dependent on the base sequence of S-probe, diastereoisomers, and the manner of hybridization. These results suggest that the conformation of the hybrid largely affected the local mobility of TEMPO and that tau value of S-probe reflected the local structure of the hybrid. When S-probe which was complementary to a single strand region of 5S RNA, was mixed with 5S RNA, tau value largely changed, indicating that the S-probe could form hybrid with 5S RNA in solution. Similar results were also obtained in the fluorescence depolarization analysis using fluorescent labeled oligonucleotide (F-probe). These results suggest that S-probe and F-probe are capable for the recognition of the secondary structure of 5S RNA in solution and useful for the analysis of the secondary structure of other nucleic acids in solution.

Base Sequence↗