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T Taira

Publications and source records attributed to T Taira.

At least 37 records · Page 2Linked to original sources
PubMed2001

The isolation and characterization of a waxy mutant of diploid wheat (Triticum monococcum L.).

A waxy mutant of diploid wheat (Triticum monococcum L.) was isolated by screening M(3) seeds derived from 1% ethyl methanesulfonate (EMS) mutagenized materials with KI-I(2) staining of endosperm starch. This mutant was controlled by a single waxy gene that completely lacked amylose, the 59-kDa waxy protein and the granule-bound starch synthase I (GBSS I) activity in the endosperm. Moreover, the T. monococcum exhibited the gene dosage effects in terms of amylose content, the amount of waxy protein and the GBSS activity. The chain length distribution of amylopectin of the waxy mutant endosperm starch slightly differed from that of the wild type; the long chains of DP>==19 were more enriched in the waxy amylopectin than those in the wild type. The mutant can be an important material for studies on starch metabolism and breeding in Triticum species.

Journal Article↗
PubMed2001

Peripheral neurotomy for torticollis: a new approach.

Most of spasmodic torticollis is classifical as cervical dystonia and the treatment of choice is chemical or surgical denervation. There are two major procedures for surgical denervation, intradural ventral rhizotomy and extradural peripheral neurotomy (Bertrand procedure). Both have advantages and disadvantages. The authors have modified these procedures to minimize the complications, with unilateral intradural ventral rhizotomy of C1 and C2, extradural denervation of the C3-C6 posterior rami, and contralateral peripheral sectioning of the branches of the spinal accessory nerve to the sternocleidomastoid muscle. 30 patients underwent this modified operation (Group A) and the results were compared with those in a matched control group of 20 patients who underwent the traditional Bertrand procedure (Group B). Only one patient in Group A showed a sensory deficit in the C2 area, while all the patients in Group B had C2 sensory disturbance. Pre- and postoperative rating scores did not differ between the two groups. The intraoperative blood loss was significantly smaller in Group A. Compared with the traditional Bertrand's operation, our procedure involves fewer complications and significantly less intraoperative blood loss.

Accessory Nerve↗
PubMed2001

New possibilities for stereotaxis. Information-guided stereotaxis.

Information-guided stereotaxis, assisted by visualization of medical information, will become the next generation of neurosurgical systems. We performed 76 open MRI surgeries at Tokyo Women's Medical University between March 3, 2000 and April 12, 2001. Of them, comparisons of pre- and post-operative MR images for malignant gliomas in 21 cases revealed an average resection rate of 90.3% (the maximum 100%, the minimum 55%). In this article we describe real time updated navigation, augmented reality navigation, three-dimensional navigation, chemical navigation, information-guided navigation system (High definition visual Computer Aided Surgery System: HivisCAS), and open MRI-guided surgery that we are developing.

Humans↗
PubMed2001

Localization, accumulation, and antifungal activity of chitinases in rye (Secale cereale) seed.

In order to understand a physiological role of chitinases in rye, the localization and accumulation of rye seed chitinase-a and -c (RSC-a and -c) in the seeds were studied by immunochemical methods. An antiserum specific to the chitin-binding domain (CB-domain), which is an N-terminal part of RSC-a, and an antiserum specific to the catalytic region of RSC-a and RSC-c were used. An immunoblot analysis detected both RSC-a and RSC-c in the endosperm of the rye seed. Immunohistochemical staining indicated that RSC-a was localized in only the aleurone cells, whereas RSC-c existed at least in the starchy endosperm and was also likely to exist in the aleurone cells. It was found by ELISA and an immunoblot analysis that RSC-a and -c accumulated in the seed during the later stage of development. Both chitinases and the Cat-domain exhibited antifungal activity toward Trichoderma species, while the CB-domain did not. Observation of the inhibition of hyphal growth of the T. species suggests that the two chitinases acted in different ways.

Antifungal Agents↗
PubMed2000

CDC6 interacts with c-Myc to inhibit E-box-dependent transcription by abrogating c-Myc/Max complex.

The c-myc oncogene product (c-Myc) is a transcription factor that dimerizes with Max and recognizes the E-box sequence. It plays key functions in cell proliferation, differentiation and apoptosis. It is generally thought that c-Myc transactivates genes encoding proteins essential to cell-cycle progression by binding to the E-boxes that control them. The functions of c-Myc are also thought to be modulated by its associated proteins, several of which have recently been identified. In this study, we found that c-Myc directly bound in vivo and in vitro to the N-terminal region of human CDC6, a component of the pre-replication complex, and that both co-localized in cell nuclei. CDC6 bound to the C-proximal region of c-Myc, thereby competing with Max on the E-box sequence and changing c-Myc/Max heterodimer to a Max/Max homodimer. In consequence, the E-box-dependent transcription activity of c-Myc was abrogated. These results suggest that, in addition to its DNA replication activity, CDC6 also has a role as a transcriptional suppressor of c-Myc.

Basic Helix-Loop-Helix Leucine Zipper Transcriptio↗
PubMed2000

High-frequency synaptic stimulation induces association of fyn and c-src to distinct phosphorylated components.

Signaling via tyrosine kinases appears necessary for regulation of synaptic efficacy. Interactions of the src-family kinases with phosphorylated proteins were studied in area CAI of rat hippocampal slices 10 min after induction of long-term potentiation (LTP) by 100 Hz/l s stimulation (HFS). HFS enhanced association of the src-family kinases fyn and c-src with an approximately 120 kDa tyrosine phosphorylated component containing the focal adhesion kinase (FAK) and its homologue PYK2. Association of fyn with FAK and of c-src with PYK2 was increased following the HFS. Further, increase in tyrosine phosphorylation of PYK2 was detected following the HFS. These results suggest that fyn and c-src are involved in distinct signaling pathways and provide evidence for activation of FAK and PYK2 following synaptic stimulation inducing LTP in vitro.

Animals↗
PubMed2000

Identification of heterochromatin protein 1 (HP1) as a phosphorylation target by Pim-1 kinase and the effect of phosphorylation on the transcriptional repression function of HP1(1).

Pim-1, a protooncogene product, is a serine/threonine kinase and is thought to play a role in signal transduction in blood cells. Few phosphorylated target proteins for Pim-1, however, have been identified. In the present study, two-hybrid screening to clone cDNAs encoding proteins binding to Pim-1 was carried out, and a cDNA for heterochromatin protein 1gamma (HP1gamma) was obtained. Binding assays both in yeast and in vitro pull-down using the purified HP1gamma and Pim-1 expressed in Escherichia coli showed that Pim-1 directly bound to the chromo shadow domain of HP1gamma. HP1gamma was also associated with Pim-1 in human HeLa cells and the serine clusters located at the center of HP1gamma were phosphorylated by Pim-1 in vitro. Furthermore, a transcription repression activity of HP1gamma was further stimulated by the deletion of the serine clusters targeted by Pim-1. These results suggest that Pim-1 affects the structure or silencing of chromatin by phosphorylating HP1.

Amino Acid Sequence↗
PubMed2000

Sp1 cooperates with c-Myc to activate transcription of the human telomerase reverse transcriptase gene (hTERT).

Telomerase activation is thought to be a critical step in cellular immortalization and carcinogenesis. The human telomerase catalytic subunit (hTERT) is a rate limiting determinant of the enzymatic activity of human telomerase. In the previous study, we identified the proximal 181 bp core promoter responsible for transcriptional activity of the hTERT gene. To identify the regulatory factors of transcription, transient expression assays were performed using hTERT promoter reporter plasmids. Serial deletion assays of the core promoter revealed that the 5'-region containing the E-box, which binds Myc/Max, as well as the 3'-region containing the GC-box, which binds Sp1, are essential for transactivation. The mutations introduced in the E-box or GC-box significantly decreased transcriptional activity of the promoter. Overexpression of Myc/Max or Sp1 led to significant activation of transcription in a cell type-specific manner, while Mad/Max introduction repressed it. However, the effects of Myc/Max on transactivation were marginal when Sp1 sites were mutated. Western blot analysis using various cell lines revealed a positive correlation between c-Myc and Sp1 expression and transcriptional activity of hTERT. Using fibroblast lineages in different stages of transformation, we found that c-Myc and Sp1 were induced to a dramatic extent when cells overcame replicative senescence and obtained immortal characteristics, in association with telomerase activation. These findings suggest that c-Myc and Sp1 cooperatively function as the major determinants of hTERT expression, and that the switching functions of Myc/Max and Mad/Max might also play roles in telomerase regulation.

Base Sequence↗
PubMed2000

Fast network oscillations in the newborn rat hippocampus in vitro.

Spontaneous neural activity is crucial for the formation of the intricate patterns of cortical connectivity during development. In particular, temporal correlations in presynaptic and postsynaptic activity have been hypothesized to be a critical determinant in the selection of neurons that are to become wired together. To date, however, temporally correlated activity in the neonatal brain has been believed to take place with a precision of tens of milliseconds to seconds. Here we describe a novel type of a fast network oscillation associated with millisecond synchronization of pyramidal cell firing in newborn rat hippocampus in vitro. Individual pyramidal neurons fired mainly at lower gamma frequencies (20-40 Hz) but were synchronized into a high-frequency (100-400 Hz) population oscillation that was reflected in field potential spikes and intracellular AMPA-kainate receptor-mediated currents. The high-frequency population oscillation was patterned by a gamma-frequency modulatory oscillation. The gamma modulation was imposed by GABAergic currents, which exerted an inhibitory action on pyramidal neurons. Patterned activity based on GABAergic inhibition and glutamatergic excitation thus occurs already in newborn hippocampus. The network oscillations described here may be a mechanism for selective coincidence detection with a millisecond range temporal precision to shape the patterns of connectivity within the emerging hippocampal synaptic circuitry.

Animals↗
PubMed2000

Voglibose administration before the evening meal improves nocturnal hypoglycemia in insulin-dependent diabetic patients with intensive insulin therapy.

Nocturnal hypoglycemia is one of the serious complications of intensive insulin therapy in patients with insulin-dependent diabetes mellitus (IDDM; type 1 DM). We assessed the effect of voglibose (alpha-glucosidase inhibitor) administration before the evening meal on nocturnal hypoglycemia in IDDM patients with intensive insulin therapy. Ten IDDM patients received 0.3 mg voglibose just before the evening meal for 5 days. The diet and insulin regimen were not changed throughout the study. Nocturnal plasma glucose levels (10 PM, 3 AM, and 7 AM) were studied in these patients before and during voglibose administration. Blood glucose levels were measured at 3 AM before and during voglibose treatment. The mean plasma glucose level at 3 AM was 3.4+/-0.4 mmol/L before voglibose treatment and 7.3+/-1.0 mmol/L during treatment. Plasma glucose at 3 AM was elevated in 9 of 10 patients with voglibose. The decrease in plasma glucose from 10 PM to 3 AM was 6.5+/-0.8 mmol/L before voglibose administration but 3.2+/-0.9 mmol/L during treatment (P < .01). The hypoglycemia rate was 52% (17 of 33 nights) before voglibose administration but only 9.1% (3 of 33 nights) during treatment. We conclude that voglibose administration before the evening meal improves nocturnal hypoglycemia in IDDM patients with intensive insulin therapy.

Adolescent↗
PubMed2000

MSSP promotes ras/myc cooperative cell transforming activity by binding to c-Myc.

BACKGROUND: MSSPs, myc single strand binding proteins, were originally identified as proteins recognizing a putative replication origin/transcriptional enhancer in the human c-Myc gene. The cDNAs encoding four of the family proteins, MSSP-1, MSSP-2, Scr2 and Scr3, were cloned. These proteins carry two copies of the putative RNA binding domains, RNP-A and RNP-B, and have been suggested to participate in DNA replication and cell cycle progression from the G1 to the S phase. RESULTS: We report that MSSP-1 and MSSP-2 bound directly to the C-terminal portion of c-Myc, along with Max, side by side. MSSP, c-Myc and Max formed a ternary complex in vivo, although MSSP did not directly associate with Max. The MSSP/Myc/Max ternary complex lost the binding activity to the E-box sequence-the recognition sequence of c-Myc/Max complex-thereby abrogating the E-box-dependent transcription activity of c-Myc. MSSP specifically stimulated the cooperative transforming activity of c-myc with ras, in a manner dependent upon the RNP sequences, while mssp itself showed no transforming activity in mouse NIH3T3 cells. The NIH3T3 transformants, together with ras, myc and mssp, grew to form very large colonies in soft agar, as compared to those with ras plus myc or ras alone. CONCLUSIONS: MSSP is a modulator of c-Myc and the c-Myc/MSSP complex may deregulate cell cycle controls and lead cells towards transforming pathways.

3T3 Cells↗
PubMed2000

ORC1 interacts with c-Myc to inhibit E-box-dependent transcription by abrogating c-Myc-SNF5/INI1 interaction.

BACKGROUND: The c-myc oncogene product (c-Myc) is a transcription factor that forms a complex with Max and recognizes the E-box sequence. c-Myc plays key functions in cell proliferation, differentiation and apoptosis. As for its activity towards cell proliferation, it is generally thought that c-Myc transactivates the E-box-containing genes that encode proteins essential to cell-cycle progression. Despite the characterization of candidate genes regulated by c-Myc in culture cells, these have still not been firmly recognized as real target genes for c-Myc. RESULTS: We found that c-Myc directly bound to the N-terminal region of origin recognition complex-1 (ORC1), a region that is responsible for gene silencing, in a state of complex containing other ORC subunits and Max in vivo and in vitro. Furthermore, ORC1 inhibited E-box-dependent transcription activity of c-Myc by competitive binding to the C-terminal region of c-Myc with SNF5, a component of chromatin remodelling complex SNF/Swi1. CONCLUSIONS: These results suggest that ORC1 suppresses the transcription activity of c-Myc by its recruitment into an inactive form of chromatin during some stage of the cell cycle.

Binding, Competitive↗
PubMed2000

Synaptic GABA(A) activation inhibits AMPA-kainate receptor-mediated bursting in the newborn (P0-P2) rat hippocampus.

The mechanisms of synaptic transmission in the rat hippocampus at birth are assumed to be fundamentally different from those found in the adult. It has been reported that in the CA3-CA1 pyramidal cells a conversion of "silent" glutamatergic synapses to conductive alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) synapses starts gradually after P2. Further, GABA via its depolarizing action seems to give rise to grossly synchronous yet slow calcium oscillations. Therefore, GABA is generally thought to have a purely excitatory rather than an inhibitory role during the first postnatal week. In the present study field potential recordings and gramicidin perforated and whole cell clamp techniques as well as K(+)-selective microelectrodes were used to examine the relative contributions of AMPA and GABA(A) receptors to network activity of CA3-CA1 pyramidal cells in the newborn rat hippocampus. As early as postnatal day (P0-P2), highly coherent spontaneous firing of CA3 pyramidal cells was seen in vitro. Negative-going extracellular spikes confined to periodic bursts (interval 16 +/- 3 s) consisting of 2.9 +/- 0.1 spikes were observed in stratum pyramidale. The spikes were accompanied by AMPA-R-mediated postsynaptic currents (PSCs) in simultaneously recorded pyramidal neurons (7.6 +/- 3.0 unitary currents per burst). In CA1 pyramidal cells synchronous discharging of CA3 circuitry produced a barrage of AMPA currents at >20 Hz frequencies, thus demonstrating a transfer of the fast CA3 network activity to CA1 area. Despite its depolarizing action, GABA(A)-R-mediated transmission appeared to exert inhibition in the CA3 pyramidal cell population. The GABA(A)-R antagonist bicuculline hypersynchronized the output of glutamatergic CA3 circuitry and increased the network-driven excitatory input to the pyramidal neurons, whereas the GABA(A)-R agonist muscimol (100 nM) did the opposite. However, the occurrence of unitary GABA(A)-R currents was increased after muscimol application from 0.66 +/- 0.16 s(-1) to 1.43 +/- 0.29 s(-1). It was concluded that AMPA synapses are critical in the generation of spontaneous high-frequency bursts in CA3 as well as in CA3-CA1 transmission as early as P0-P2 in rat hippocampus. Concurrently, although GABA(A)-R-mediated depolarization may excite hippocampal interneurons, in CA3 pyramidal neurons it can restrain excitatory inputs and limit the size of the activated neuronal population.

2-Amino-5-phosphonovalerate↗
PubMed2000

[Copper supplement with cocoa for copper deficiency in patients with long-term enteral nutrition].

Copper deficiency (normal serum copper level: 78-136 micrograms/dl) has been reported in patients with long-term enteral nutrition, caused by a copper deficit in enteral nutrition. Occasionally, this leads to anemia and leukopenia. We used Hershey's pure cocoa that is rich in copper (content 3.8 mg/cocoa 100 g) for copper deficiency. A total of 86 (40 men and 46 women, mean age 69 years) patients on enteral nutrition were studied. The primary diseases were cerebral vascular disease in 71 patients, neurological disease in 5 and others in 10. Those who showed serum copper levels of 20 micrograms/dl or less (N = 8) were given 30-45 g of cocoa (copper content 1.14-1.71 mg) per day for about 40 days. Among them, two patients could not continue because of vomiting and diarrhea and were excluded from this study. Mean serum copper levels increased from 8.7 +/- 6.2 to 99.0 +/- 25.4 micrograms/dl (N = 6). Those who showed serum copper levels 20-77 mg/dl (N = 31) were given 10 g of cocoa (copper content 0.38 mg) per day for about 40 days. When mean serum copper levels increased from 50.5 +/- 19.3 to 89.0 +/- 12.9 micrograms/dl with cocoa administration, anemia and neutropenia caused by copper deficiency showed a tendency to improve. After completing the study period, cocoa was reduced to 5 g (copper content 0.19 mg) per day in 23 patients. The mean serum copper levels increased from 90.7 +/- 10.4 to 100.6 +/- 17.1 micrograms/dl for about 100 days. Recently, the amount of daily copper requirement for adults has been reported to be 1.28-2.5 mg per day. We showed that 10 g of cocoa (0.6 mg total copper: 0.38 mg in cocoa and 0.22 mg in other nutrients) is sufficient to treat copper deficiency, and 5 g of cocoa (0.37 mg total copper: 0.19 mg in cocoa and 0.18 mg in other nutrients) is enough to maintain the normal level of serum copper in patients with long-term enteral nutrition.

Aged↗
PubMed2000

AMY-1 is a trigger for the erythrocyte differentiation of K562 cells.

We have reported that a novel c-Myc binding protein, AMY-1, stimulated the transcription activity of c-Myc and was translocated from cytoplasm to nuclei in a c-Myc-dependent manner. Here, the role of AMY-1 in cell differentiation was examined. AMY-1 expression was up-regulated after differentiation induction of human K562 cells to erythrocyte cells by AraC, while c-Myc expression was rapidly down-regulated. K562 cell lines expressing exogenous AMY-1 were established, and these cells expressed a high level of epsilon-globin mRNA, a marker gene necessary for erythrocyte cell differentiation, without differentiation induction. The addition of AraC rapidly initiated differentiation in these cell lines, which continued to differentiate to erythrocyte cells possessing a high level of hemoglobin even after the decrease in AMY-1 expression. These results suggest that AMY-1 is a trigger for K562 cells to differentiate to erythrocyte cells and that AMY-1 may have a function independent of or different from c-Myc.

Antimetabolites, Antineoplastic↗