Biomedical subjects

M Iwabuchi

Publications and source records attributed to M Iwabuchi.

At least 19 recordsLinked to original sources

PubMed2006

Effectiveness of an 'half elemental diet' as maintenance therapy for Crohn's disease: A randomized-controlled trial.

BACKGROUND: Although thiopurines have a proven role in maintenance therapy for Crohn's disease, an alternative therapy is needed for patients intolerant or resistant to thiopurines. AIM: To evaluate the effectiveness of home enteral nutrition as a maintenance therapy regimen in which half of the daily calorie requirement is provided by an elemental diet and the remaining half by a free diet. We refer to this home enteral nutrition therapy as 'half elemental diet'. METHODS: Between 2002 and 2005, 51 patients in remission from two hospitals were randomly assigned to a half elemental diet group (n = 26) or a free diet group (n = 25). The primary outcome measure of this study was the occurrence of relapse over the 2-year period. RESULTS: The relapse rate in the half elemental diet group was significantly lower [34.6% vs. 64.0%; multivariate hazard ratio 0.40 (95% CI: 0.16-0.98)] than that in the free diet group after a mean follow-up of 11.9 months. Compliance was similar in the two groups. No adverse event occurred in any of the patients throughout the study. CONCLUSION: This randomized-controlled trial shows the effectiveness of an half elemental diet, which is a promising maintenance therapy for Crohn's disease patients.

Adult↗

PubMed2005

Overexpression of gastrin-releasing peptide receptor induced layer disorganization in brain.

Gastrin-releasing peptide-preferring and neuromedin B-preferring receptors, members of the bombesin-like peptide receptor subfamily, are reported to regulate proliferation, migration and differentiation. Since they are expressed in developing brain, we postulated that the gastrin-releasing peptide-preferring and neuromedin B-preferring receptors might be involved in normal brain development. Here we examined the effects of the overexpressions of the gastrin-releasing peptide-preferring and neuromedin B-preferring receptors on chick brain development in vivo using a retrovirus. In the overexpressed exogenous gastrin-releasing peptide-preferring receptor brain, we found laminar disorganization in the telencephalon, tectum and particularly in the cerebellum with severe atrophy. Processes of the radial glial cells in the telencephalon and optic tectum, as well as the projections of the Bergmann glia in the cerebellum were distorted, which might disturb normal cell migration. Despite the atrophy of the cerebellum, densely-stained proliferating cell nuclear antigen- and phospho-histone H3-positive cells increased in number. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cells also increased in the cerebellum, suggesting that the ectopically proliferating cells were subjected to apoptosis. Glial fibrillary acidic protein-positive cells also increased in the hyperpallium accessorium and in the outer layers of the tectum. We also found smaller and spindle-shaped cells which resembled undifferentiated embryonic tumor cells. On the other hand, the layer structures of the neuromedin B-preferring receptors overexpressed brain were well organized and developed, and the size of brain was generally enlarged. These results indicated that although the gastrin-releasing peptide-preferring and neuromedin B-preferring receptors are involved in normal brain development, both receptors contribute and exert their effects differently.

Animals↗

PubMed2003

Thermoinduction of genes encoding the enzymes of gibberellin biosynthesis and a putative negative regulator of gibberellin signal transduction in Eustoma grandiflorum.

Eustoma grandiflorum Shinn requires vernalization for the induction of stem elongation and flowering. To investigate the role of gibberellins (GAs) in vernalization, the expression levels of genes encoding enzymes of GA biosynthesis, copalyl diphosphate synthetase, GA 20-oxidase and GA 3 beta-hydroxylase, were examined using two culitvars that show different responses to vernalization. The three genes were induced in a vernalization- and a cultivar-dependent manner. EgSPY, a putative negative regulator of GA signal transduction, was also induced during the vernalization period. The results suggest that the expression of the genes encoding GAs biosynthesis is regulated by vernalization. We postulate that EgSPY functions as a negative regulator of GA signal transduction during vernalization, inhibiting adventitious shoot elongation during vernalization.

Alkyl and Aryl Transferases↗

PubMed2001

Effects of anulus fibrosus and experimentally degenerated nucleus pulposus on nerve root conduction velocity: relevance of previous experimental investigations using normal nucleus pulposus.

STUDY DESIGN: Nerve conduction velocity was measured in the pig cauda equina after local application of anulus fibrosus or in vitro/postmortem degenerated nucleus pulposus from the same pig. OBJECTIVES: To analyze the effects of anulus fibrosus and degenerated nucleus pulposus on nerve conduction velocity. SUMMARY OF BACKGROUND DATA: Previous studies on nucleus pulposus-induced effects on nerve roots have used normal, nondegenerated nucleus pulposus. Because both anulus fibrosus and degenerated nucleus pulposus are commonly seen in the clinical situation of disc herniation, the value of the previous work could be questioned. METHODS: Anulus fibrosus and nucleus pulposus were harvested using a retroperitoneal approach. The nucleus pulposus was degenerated artificially either by addition of sodium lactate with HCl added to form a pH of either 6.0 or 3.5 (in vitro degeneration), or by storing the nucleus pulposus at 4 C until a pH of 6.0 (postmortem degeneration) was reached. After epidural application, the nerve conduction velocity was determined at 7 days (anulus fibrosus) or 3 days (degenerated nucleus pulposus). RESULTS: Application of anulus fibrosus did not induce any reduction of nerve conduction velocity. In vitro and postmortem degenerated nucleus pulposus induced a reduction of nerve conduction velocity similar to that of normal nucleus pulposus. CONCLUSIONS: Although only nerve function and not pain was assessed, it seems likely that previous experiments using normal nucleus pulposus may be relevant for evaluating the pathophysiologic mechanisms behind the nucleus pulposus-induced nerve root injury, also in a clinical perspective.

Animals↗

PubMed2001

FASCIATA genes for chromatin assembly factor-1 in arabidopsis maintain the cellular organization of apical meristems.

Postembryonic development of plants depends on the activity of apical meristems established during embryogenesis. The shoot apical meristem (SAM) and the root apical meristem (RAM) have similar but distinct cellular organization. Arabidopsis FASCIATA1 (FAS1) and FAS2 genes maintain the cellular and functional organization of both SAM and RAM, and FAS gene products are subunits of the Arabidopsis counterpart of chromatin assembly factor-1 (CAF-1). fas mutants are defective in maintenance of the expression states of WUSCHEL (WUS) in SAM and SCARECROW (SCR) in RAM. We suggest that CAF-1 plays a critical role in the organization of SAM and RAM during postembryonic development by facilitating stable maintenance of gene expression states.

Amino Acid Sequence↗

PubMed2001

Elevated sensitivity to gibberellin by vernalization in the vegetative rosette plants of Eustoma grandiflorum and Arabidopsis thaliana.

Changes in the sensitivity to gibberellin (GA) after vernalization were studied in the vegetative rosette of Eustoma grandiflorum and late flowering Arabidopsis thaliana mutant, fca-1. The sensitivity to GA after vernalization was monitored using the bolting rate of plants that were grown on a medium containing GA(3) or ancymidol. The bolting rates were higher in vernalized plants than non-vernalized plants when the same GA(3) concentration was used. There was a positive relationship between the duration of vernalization and the bolting rate in E. grandiflorum. In contrast, a negative relationship between the duration of treatment and bolting rate was found in the non-vernalized plants. In fca-1, the flowering time of vernalized plants was significantly reduced compared with the non-vernalized plants under various concentrations of GA(3) treatment. To elucidate whether this elevated sensitivity relates to the efficiency of GA signal transduction, we measured the transcript amounts of Expansin (Exp), which is up-regulated by GA, and GA20-oxidase (GA20ox) and GA3 beta-hydroxylase (GA3betahy), which are down-regulated by GA. The transcript amounts were estimated using the Taq-Man PCR system based on combinations of primers and probes that specifically detect the genes, and normalized by the transcript amount of ubiquitin gene measured as an internal standard. For each concentration of GA treatments examined, Expansin of both E. grandiflorum and A. thaliana was induced at a higher rate in the vernalized plants than in the non-vernalized plants. The expression of GA20ox and GA3betahy of E. grandiflorum decreased faster in the vernalized plants than the non-vernalized plants. We conclude that vernalization is a critical environmental cue not only for initiating GA biosyntheses in vegetative rosette, but also for elevating the GA sensitivity of the plants via a GA signal transduction pathway.

Journal Article↗

PubMed2001

Fetal aortic blood flow assessment from the relationship between fetal aortic diameter pulse and flow velocity waveforms during fetal development.

BACKGROUND: Blood flow is calculated from mean velocity across the vessel and its cross-sectional area and is related to the fetal growth. AIM: To investigate the relationship between diameter pulse waveform (DPW) and flow velocity waveform (FVW) in the fetal descending aorta during fetal development. STUDY DESIGN: Doppler ultrasound and a phase-locked loop echo tracking system were used to measure the FVW and DPW in the fetal descending aorta, respectively. SUBJECTS: We studied 137 normal-growth fetuses (normal group, 20-40 weeks) and 51 fetuses with high umbilical artery pulsatility index (umbilical placental insufficiency, UPI group, 26-40 weeks). OUTCOME MEASURES: We measured the systolic (Sd), diastolic (Dd) diameters, time diameter integral (TDI) and time velocity integral (TVI) and then calculated the TVI x TDI and TVI to TDI ratio. RESULTS: Normal fetal growth was associated with an increase in Sd, Dd, pulse amplitude, TVI, TDI and TVI x TDI. The FVW began to resemble the DPW with decreasing downstream resistance produced by growth of the placenta. The TVI was increased relative to the TDI. The differences in Sd, Dd, TDI and TVI x TDI between the normal and UPI groups were not significant. The TVI was decreased relative to the TDI. There was a decrease in the TVI as a ratio of the TDI. The Dd per unit fetal weight was high in the compromised fetuses. Fetal outcome was examined in relation to the TVI to TDI ratio. Those with a low ratio (below 10th centile) exhibited significantly more adverse indices of fetal outcome. CONCLUSIONS: In fetal compromise there is an increase in diastolic pressure in association with high placental resistance, which causes a major increase in afterload. The efficient circulation associated with fetal growth might be represented by an increase in the ratio of the TVI to the TDI (an index of efficient circulation) when these waveform shapes resemble each other.

Adult↗

PubMed2001

A mechanism for promoting the germination of Zinnia elegans seeds by hydrogen peroxide.

H(2)O(2) promotes seed germination of cereal plants such as barley, wheat and rice, and several mechanisms have been proposed for its action [Naredo et al. (1998) Seed Sci. Technol. 26: 675-689]. We investigated the role of H(2)O(2) in the germination of Zinnia elegans seeds. H(2)O(2) promoted seed germination in a dose-dependent manner as did respiratory inhibitors, indicating that H(2)O(2) itself possibly promotes seed germination rather than O(2). Seed germination was promoted by removal of pericarp from seeds or by removal of ethanol-soluble compounds from the seeds with pericarp. The ethanol-soluble compounds suppressed the germination of seeds having no pericarp, and this effect was reversed by H(2)O(2). These findings indicate that oxidation of the germination inhibitor(s) present in the pericarp by H(2)O(2) promotes seed germination. Antioxidants which are derivatives of well-known germination inhibitors suppressed seed germination in a dose-dependent manner, suggesting that, to initiate seed germination, a germination inhibitor(s) should be decomposed by an oxidant such as H(2)O(2).

Antioxidants↗

PubMed2001

Association of glutathione with flowering in Arabidopsis thaliana.

In order to study the relationship between GSH and flowering, wild-type and late-flowering mutant, fca-1, of Arabidopsis thaliana were treated with L-buthionine sulfoximine (BSO), a specific inhibitor of GSH biosynthesis, under long-day conditions. BSO treatment of the fca-1 mutant starting at 17 d after imbibition promoted flowering. However, when the treatment was started at 12 d after imbibition, BSO treatment at 10(-4) M resulted in an inhibition of flowering. This inhibitory effect of BSO on flowering was abolished by GSH treatment at 10(-4) M, although GSH treatment at an increased concentration of 10(-3) M clearly delayed flowering. In contrast, BSO treatment of wild-type plants starting at 12 d after imbibition promoted flowering, whose effect was abolished by GSH application. In the fca-1 mutant, whose endogenous GSH levels were high, chilling treatment lowered the GSH levels and promoted flowering, as was the case in the BSO treatment. An A. thaliana mutant, cad2-1, which has a defect in GSH biosynthesis also exhibited late flowering. The late-flowering phenotype of this mutant tended to be strengthened by BSO and abolished by GSH treatment. These results suggest that flowering is associated with the rate of GSH biosynthesis and/or the levels of GSH in A. thaliana.

Arabidopsis↗

PubMed2001

A possible role of glutathione and glutathione disulfide in tracheary element differentiation in the cultured mesophyll cells of Zinnia elegans.

We investigated the relationship between the cellular redox state of GSH or GSSG and tracheary element (TE) differentiation using a Zinnia experimental system, in which isolated mesophyll cells transdifferentiate to TEs. TE differentiation was suppressed by the application of L-buthionine sulfoximine (BSO), a potent inhibitor of GSH biosynthesis, at the early stage of cell culture. Application of GSSG at the early culture stage promoted the differentiation, but that of GSH or GSSG at an advanced period of culture suppressed the differentiation. Application of GSH and GSSG nullified the TE differentiation-suppressing effect of BSO. The results suggest that changes in the redox states of GSH and GSSG have a role in TE differentiation.

Asteraceae↗

PubMed2000

Residual Cdc2 activity remaining at meiosis I exit is essential for meiotic M-M transition in Xenopus oocyte extracts.

To investigate the regulatory mechanisms of the cell cycle transition from M phase to M phase in meiotic cycles, a Xenopus oocyte extract that performs the M-M transition has been developed. Using the meiotic extract, we found that a low level of Cdc2 activity remained at the exit of meiosis I (MI), due to incomplete degradation of cyclin B. The inactivation of the residual Cdc2 activity induced both entry into S phase and tyrosine phosphorylation on Cdc2 after MI. Quantitative analysis demonstrated that a considerable amount of Wee1 was present at the MI exit and Cdc2 inhibitory phosphorylation during this period was suppressed by the dominance of Cdc2 over Wee1. Consistently, the addition of more than a critical amount of Wee1 to the extract induced Cdc2 inhibitory phosphorylation, changing the M-M transition into an M-S-M transition. Thus, the Cdc2 activity remaining at MI exit is required for suppressing entry into S phase during the meiotic M-M transition period.

Animals↗

PubMed2000

Expression of a subset of the Arabidopsis Cys(2)/His(2)-type zinc-finger protein gene family under water stress.

The genes encoding Cys(2)/His(2)-type zinc-finger proteins constitute a large family in higher plants. To elucidate the functional roles of these types of protein, four different members of the gene family were cloned from Arabidopsis by PCR-aided methods. One was identical to the already reported gene STZ/ZAT10 and three were as yet unidentified genes, then designated AZF1 (Arabidopsis zinc-finger protein 1), AZF2 and AZF3. The AZF- and STZ-encoded proteins contain two canonical Cys(2)/His(2)-type zinc-finger motifs, separated by a long spacer. Three conserved regions, named B-box, L-box, and DNL-box, were also recognized outside the zinc-finger motifs, as in other members of the two-fingered Cys(2)/His(2)-type zinc-finger protein family. These four genes were positioned on the same branch of a phylogenetic tree constructed based on the zinc-finger motif sequences, suggesting their structural and functional relationship. RNA blot analysis showed that all four genes were mainly expressed in roots and at different levels in other organs. Expression of the four genes responded to water stress. High-salt treatment resulted in elevated levels of expression of all of these genes. Low-temperature treatment increased the expression levels of AZF1, AZF3, and STZ, but not AZF2. Only AZF2 expression was strongly induced by ABA treatment, where the time course of the induction was similar to that caused by high salinity. In situ localization showed that AZF2 mRNA accumulated in the elongation zone of the roots under the salt-stress condition. These results suggest that AZF1, AZF2, AZF3, and STZ are all involved in the water-stress response in an ABA-dependent or -independent pathway to regulate downstream genes.

Abscisic Acid↗

PubMed2000

S phase-specific DNA-binding proteins interacting with the Hex and Oct motifs in type I element of the wheat histone H3 promoter.

The type I element (CCACGTCANCGATCCGCG), consisting of the Hex motif (CCACGTCA) and the reverse-oriented Oct motif (GATCCGCG), is necessary and sufficient to confer the S phase-specific transcription of the wheat histone H3 (TH012) gene. The transcriptional regulation via the type I element is thought to occur through interactions between transcription factors which bind specifically to the Hex and Oct motifs. Here we report S phase-specific DNA-binding proteins interacting with the type I element in partially synchronized wheat cultured cells. Hex motif-binding proteins found here resembled HBP-1a, as reported previously in terms of DNA-binding specificity. DNA-binding activities of the HBP-1a-like proteins were modulated by phosphorylation/dephosphorylation. In the electrophoretic mobility shift assay of the wheat nuclear extract, we also found three Oct motif-specific binding proteins, named OBRF (octamer-binding regulatory factor)-1, -2 and -3. One of the HBP-1a-like proteins and OBRF-1 appeared predominantly at the S phase. Thus, it was supposed that these two factors play a crucial role in the S phase-specific regulation of wheat histone gene expression.

Binding Sites↗

PubMed2000

Ten-years clinical follow-up following successful percutaneous transvenous mitral commissurotomy: single-center experience.

The purpose of this study is to report the long-term follow-up outcome of patients undergoing percutaneous transvenous mitral commissurotomy (PTMC). The follow-up of 68 of 82 (83%) consecutive patients undergoing successful PTMC (mitral valve area of more than 1.5 cm(2) without major complications) in 1987 using the Inoue balloon was analyzed. The mean age at the time of PTMC was 52 +/- 11 years and 81% were female patients. The mean follow-up interval was 98 +/- 37 months (6 to 123). Actuarial survival rate was 98%, 97%, and 86% at 1, 5, and 10 years, respectively; the event-free (death, mitral valve replacement, and repeat PTMC) survival rate was 90%, 85%, and 66% at 1, 5, and 10 years, respectively. According to the echocardiographic findings, patients could be divided into three groups: pliable valve, semipliable valve, and rigid valve. Multivariable analysis identified echocardiographic subgrouping as the major significant predictor of any event: the event-free survival rate being 70% in group 1, 66% in group 2, and 20% in group 3 (P < 0.05). Echocardiographic follow-up was available in 49 of 68 patients (72%); the mitral valve area changed from 1.4 +/- 0.5 before to 2.1 +/- 0.4 immediately post-PTMC, and 1.8 +/- 0.4 cm(2) 10 years after the procedure. The long-term follow-up outcome following successful PTMC was favorable and seems to support it as a viable alternative to surgical commissurotomy in selected patients. Patients with rigid valves should be selected very carefully.

Adult↗

PubMed2000

Regulation of histone gene expression during the cell cycle.

The steady-state level of histone mRNAs fluctuates coordinately with chromosomal DNA synthesis during the cell cycle. Such an S phase-specific expression pattern results from transcriptional activation of histone genes coupled with the onset of replication and from transcriptional repression of the genes as well as specific destabilization of histone mRNAs around the end of the S phase. Proliferation-coupled and S phase-specific expression of histone genes is primarily achieved by the activities of the proximal promoter regions, where several conserved cis-acting elements have been identified. Among them, three kinds of Oct-containing composite elements (OCEs) play a pivotal role in S phase-specific transcriptional activation. Other ones, such as Nona, solo-Oct, and CCGTC motifs, appear to modulate the functions of OCEs to enhance or repress the transcriptional level, possibly depending on the state of the cells. Here, we review the growing evidence concerning the regulatory mechanisms by which plant histone genes are expressed S phase-specifically in proliferating cells.

DNA Replication↗

PubMed2000

hosoba toge toge, a syndrome caused by a large chromosomal deletion associated with a T-DNA insertion in Arabidopsis.

We isolated a T-DNA-tagged mutant named hosoba toge toge (hot) in which a pleiotropic phenotype was observed in both the shoot and root throughout the life cycle. The phenotype and allelism indicated that the mutant has a defect in both the FASCIATA1 (FAS1) gene and the FT gene located on the bottom arm of chromosome 1. Analysis of the junctions between the T-DNA ends and the plant genome suggested the presence of a 75.8-kbp deletion at the insertion site. In addition to FAS1 and FT, 13 genes were predicted to exist in the region corresponding to that deleted in hot. They include homologs of genes for type II inositol-1,4,5-triphosphate 5-phosphatase (IP5Pase), the beta-chain of N-acetyl-beta-glucosaminidase (NAGase), NADPH oxidoreductase of the zeta-crystallin family, polygalacturonase, and endo-1,4-beta-glucanase. Although most aspects of the hot phenotype can be explained by loss of FAS1 and FT functions, some novel phenotypic features which may represent aspects of a mutant phenotype due to loss-of-function of other gene(s) were observed. One "wild-type" ecotype and a previously reported T-DNA insertion line, neither of which has any obvious phenotypic abnormality, carry a possible loss-of-function mutation in the zeta-crystallin homolog and in the NAGase beta chain homolog, respectively.

Arabidopsis↗

PubMed2000

AHM1, a novel type of nuclear matrix-localized, MAR binding protein with a single AT hook and a J domain-homologous region.

Interactions between the nuclear matrix and special regions of chromosomal DNA called matrix attachment regions (MARs) have been implicated in various nuclear functions. We have identified a novel protein from wheat, AT hook-containing MAR binding protein1 (AHM1), that binds preferentially to MARs. A multidomain protein, AHM1 has the special combination of a J domain-homologous region and a Zn finger-like motif (a J-Z array) and an AT hook. For MAR binding, the AT hook at the C terminus was essential, and an internal portion containing the Zn finger-like motif was additionally required in vivo. AHM1 was found in the nuclear matrix fraction and was localized in the nucleoplasm. AHM1 fused to green fluorescent protein had a speckled distribution pattern inside the nucleus. AHM1 is most likely a nuclear matrix component that functions between intranuclear framework and MARs. J-Z arrays can be found in a group of (hypothetical) proteins in plants, which may share some functions, presumably to recruit specific Hsp70 partners as co-chaperones.

Amino Acid Sequence↗

PubMed2000

Fetal haemodynamic changes in fetuses during fetal development evaluated by arterial pressure pulse and blood flow velocity waveforms.

OBJECTIVE: To study the relation between diameter pulse (pressure pulse) and flow velocity waveforms in the fetal descending aorta in fetuses with intrauterine growth retardation and acceleration. DESIGN: Blood flow through a tubular system can be expressed by the ratio of blood pressure to vascular resistance. Doppler ultrasound and a phase locked loop echo tracking system coupled to a B-mode ultrasonic imager (central frequency 3.5 MHz) were used to assess downstream resistance and change in blood pressure, respectively. SETTING: Tertiary referral unit in a teaching hospital PARTICIPANTS: Serial study between 21 and 40 weeks of 22 women with normally grown fetuses at intervals of four weeks; 25 women with small for gestational age fetuses with uteroplacental insufficiency (high umbilical artery pulsatility index); and six women with large for gestational age fetuses. MAIN OUTCOME MEASURES: We measured the maximum systolic and minimum diastolic diameter of the fetal descending aorta (the pulse amplitude) and then calculated the pulsatile waveform time integral above the least diastolic diameter (pulsatile area) and total waveform time integral (perfusion area). RESULTS: Normal fetal growth was associated with an increase in systolic and diastolic diameters in the fetal descending aorta with advancing gestational age. Pulse amplitude, pulsatile and perfusion areas increased with gestational age. The increased pulse amplitude and increased pulsatile area in association with a decrease of the pulsatility index in the descending aorta during the second trimester suggested that pulse pressure and stroke volume were increased. In the group with intrauterine growth retardation, systolic and diastolic diameters of the descending aorta and perfusion area were within the normal range. Moreover, there was an increase in the diastolic diameter per unit fetal weight and a decrease in the pulsatile area. In the large for gestational age fetuses, there was an increase in the pulse amplitude and pulsatile area. CONCLUSION: These findings suggest that in growth restricted fetuses there is an increase in diastolic pressure and a reduction in stroke volume, while in large for gestational age fetuses there is an increase in the pulse pressure and stroke volume. It is possible that measurement of pressure pulse waveform in relation to Doppler velocity waveform may be used to infer changes of blood flow.

Blood Flow Velocity↗