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Takashi Ueda

Publications and source records attributed to Takashi Ueda.

At least 55 records · Page 3Linked to original sources
PubMed2004

Off-pump quintuple coronary artery bypass grafting for situs inversus totalis.

Dextrocardia associated with situs inversus totalis is a rare condition. A 49-year-old man with dextrocardia and situs inversus totalis underwent off-pump quintuple coronary artery bypass grafting using bilateral internal thoracic arteries and bilateral radial arteries. The operative technique was similar to that of off-pump coronary artery bypass grafting for situs solitus. His postoperative recovery was uneventful.

Coronary Artery Bypass↗
PubMed2004

The cerebrovascular dilatation effects of olprinone, a phosphodiesterase III inhibitor, in comparison with acetazolamide--a pilot study.

To examine the effects of olprinone, a phosphodiesterase III inhibitor, on cerebral blood flow (CBF), we compared the effects of olprinone on CBF to that of acetazolamide. Using technetium-99m-ethyl cysteinate dimer (99mTc-ECD) brain SPECT, we measured regional CBF (rCBF) at 33 sites, including 16 right and left pairs of non-infarct cerebral cortexes, in seven stroke patients (66.0+/-3.2 years) in a resting state and 15 min after the administration of acetazolamide. Within 1 week, rCBF at each site was measured 15 min after the initiation of olprinone infusion. Resting rCBF showed a significant negative correlation with the change in rCBF (DeltaCBF) during olprinone infusion (r = -0.43, P=0.013), but no significant correlation was seen following acetazolamide administration. The difference in rCBF between the right and left cortex increased more following acetazolamide administration (14.1+/-10.9 ml/(min 100 g)) than during olprinone infusion (5.4+/-4.8 ml/(min 100 g), P=0.013). The rCBF at four regions of interest (ROI) with low-resting CBF (< 49 ml/(min 100 g)) further decreased following the administration of acetazolamide. The vasodilatory effects of olprinone are dependent on resting CBF instead of on the intracerebral steal phenomenon that occurs with acetazolamide.

Acetazolamide↗
PubMed2004

Aortic valve replacement in a patient with a patent internal thoracic artery graft.

Myocardial protection in patients requiring a second open-heart surgical procedure after coronary artery bypass grafting, especially when there is a patent left internal thoracic artery graft to the left anterior descending coronary artery, remains controversial. We present the case of a patient in whom aortic valve replacement was undertaken 18 months after coronary artery revascularization. Unusual features included beating-heart aortic valve replacement with continuous retrograde coronary sinus perfusion and avoidance of dissection of the patent grafts, including the left internal thoracic artery and a saphenous vein graft.

Aged↗
PubMed2004

Functional differentiation of endosomes in Arabidopsis cells.

Endocytosis plays an important role in plant physiology, but how endocytic organelles are organized remains unknown. We present the evidence that endosomes are functionally differentiated in Arabidopsis cells. Two types of Rab5-related GTPases are localized on distinct population of endosomes in a partially overlapping manner. Ara7 and Rha1 are on an early type of endosomes with AtVamp727, where recycling of plasma membrane proteins occurs. In contrast, the plant-unique Rab5, Ara6, resides on distinct endosomes with the prevacuolar SNAREs. Partially overlapping localization of Ara6 and Ara7/Rha1 with reciprocal gradients suggests maturation of endosomes from one to the other.

Arabidopsis↗
PubMed2004

Systematic analysis of SNARE molecules in Arabidopsis: dissection of the post-Golgi network in plant cells.

In all eucaryotic cells, specific vesicle fusion during vesicular transport is mediated by membrane-associated proteins called SNAREs (soluble N-ethyl-maleimide sensitive factor attachment protein receptors). Sequence analysis identified a total of 54 SNARE genes (18 Qa-SNAREs/Syntaxins, 11 Qb-SNAREs, 8 Qc-SNAREs, 14 R-SNAREs/VAMPs and 3 SNAP-25) in the Arabidopsis genome. Almost all of them were ubiquitously expressed through out all tissues examined. A series of transient expression assays using green fluorescent protein (GFP) fused proteins revealed that most of the SNARE proteins were located on specific intracellular compartments: 6 in the endoplasmic reticulum, 9 in the Golgi apparatus, 4 in the trans-Golgi network (TGN), 2 in endosomes, 17 on the plasma membrane, 7 in both the prevacuolar compartment (PVC) and vacuoles, 2 in TGN/PVC/vacuoles, and 1 in TGN/PVC/plasma membrane. Some SNARE proteins showed multiple localization patterns in two or more different organelles, suggesting that these SNAREs shuttle between the organelles. Furthermore, the SYP41/SYP61-residing compartment, which was defined as the TGN, was not always located along with the Golgi apparatus, suggesting that this compartment is an independent organelle distinct from the Golgi apparatus. We propose possible combinations of SNARE proteins on all subcellular compartments, and suggest the complexity of the post-Golgi membrane traffic in higher plant cells.

Amino Acid Sequence↗
PubMed2004

[Functional analysis of acid sensing ion channels].

Acid-sensing ion channel-2a (ASIC2a) is a proton-gated cation channel, probably contributing to sour-taste detection in rat taste cells. We found the transcripts of ASIC2b in the circumvallate, foliate and fungiform papillae. Immunohistochemical analyses also revealed that ASIC2b, as well as ASIC2a, was expressed in a subpopulation of taste cells, and some of the cells displayed both ASIC2a and ASIC2b immunoreactivities. Coimmunoprecipitation studies with circumvallate papillae extracts indicated that ASIC2b associated with ASIC2a to form assemblies. Oocyte electrophysiology demonstrated that the ASIC2a/ASIC2b channel generated amiloride-insensitive currents at pH 2.0. These findings provide persuasive explanations for the amiloride insensitivity of acid-induced responses of rat taste cells. Acid-sensing ion channels (ASICs) also mediate acid-induced nociception in mammals. In our psychophysical experiments, direct infusion of acidic solutions (pH > or = 6.0) into human skin caused localized pain, which was blocked by amiloride, an inhibitor of ASICs, but not by capsazepine, an inhibitor of TRPV1. Under more severe acidification (pH 5.0) amiloride was less effective in reducing acid-evoked pain. In addition, capsazepine had a partial blocking effect under these conditions. Amiloride itself did not block capsaicin-evoked localized pain. Our results suggest that ASICs (ASIC1a and ASIC3) are leading acid sensors in human nociceptors and that TRPV1 participates in the nociception mainly under extremely acidic conditions.

Acid Sensing Ion Channels↗
PubMed2004

[Animal experimental models for acute pancreatitis].

In acute pancreatitis, multiple organ failure in the early phase and infectious complications in the late phase are contributors to mortality. To analyze the mechanism of aggravation of acute pancreatitis is to investigate the mechanism of organ dysfunction and infection. As strategy to elucidate the mechanism, various animal experimental models are utilized. Caerulein-induced pancreatitis and bile salt-induced pancreatitis (duct injection model) are frequently employed for mild edematous pancreatitis and severe necrotizing pancreatitis, respectively. It is important to select an appropriate experimental model that corresponds to the purpose of study.

Acute Disease↗
PubMed2004

[New aspects of pharmaco-therapy for acute pancreatitis].

Despite improvement in intensive medical care management, the mortality rate from severe acute pancreatitis is still high. Attempt to reduce the mortality rate, some new drugs were investigated on experimental pancreatitis and clinical cases. There have been several clinical trials of somatostatin, somatostatin analogue octreotide, and a cholecystokinin A(CCK-A) receptor antagonist, loxiglumide, for the inhibition of pancreatic secretion. On the other hand, for the inhibition of the systemic inflammatory response, many studies in the use of the platelet-activating factor(PAF) antagonist, lexipafant, were reported in clinical trials. IS-741, a new synthetic anti-inflammatory agent, has been studied on various models of experimental pancreatitis. In this paper, it is introduced the results of these new drugs on experimental pancreatitis or clinical trials.

Acute Disease↗
PubMed2003

Arabidopsis sterol endocytosis involves actin-mediated trafficking via ARA6-positive early endosomes.

BACKGROUND: In contrast to the intense attention devoted to research on intracellular sterol trafficking in animal cells, knowledge about sterol transport in plant cells remains limited, and virtually nothing is known about plant endocytic sterol trafficking. Similar to animals, biosynthetic sterol transport occurs from the endoplasmic reticulum (ER) via the Golgi apparatus to the plasma membrane. The vesicle trafficking inhibitor brefeldin A (BFA) has been suggested to disrupt biosynthetic sterol transport at the Golgi level. RESULTS: Here, we report on early endocytic sterol trafficking in Arabidopsis root epidermal cells by introducing filipin as a tool for fluorescent sterol detection. Sterols can be internalized from the plasma membrane and localize to endosomes positive for the early endosomal Rab5 GTPase homolog ARA6 fused to green fluorescent protein (GFP) (ARA6-GFP). Early endocytic sterol transport is actin dependent and highly BFA sensitive. BFA causes coaccumulation of sterols, endocytic markers like ARA6-GFP, and PIN2, a polarly localized presumptive auxin transport protein, in early endosome agglomerations that can be distinguished from ER and Golgi. Sterol accumulation in such aggregates is enhanced in actin2 mutants, and the actin-depolymerizing drug cytochalasin D inhibits sterol redistribution from endosome aggregations. CONCLUSIONS: Early endocytic sterol trafficking involves transport via ARA6-positive early endosomes that, in contrast to animal cells, is actin dependent. Our results reveal sterol-enriched early endosomes as targets for BFA interference in plants. Early endocytic sterol trafficking and recycling of polar PIN2 protein share a common pathway, suggesting a connection between plant endocytic sterol transport and polar sorting events.

Actins↗
PubMed2003

Functional interaction between T2R taste receptors and G-protein alpha subunits expressed in taste receptor cells.

Bitter taste perception is a conserved chemical sense against the ingestion of poisonous substances in mammals. A multigene family of G-protein-coupled receptors, T2R (so-called TAS2R or TRB) receptors and a G-protein alpha subunit (Galpha), gustducin, are believed to be key molecules for its perception, but little is known about the molecular basis for its interaction. Here, we use a heterologous expression system to determine a specific domain of gustducin necessary for T2R coupling. Two chimeric Galpha16 proteins harboring 37 and 44 gustducin-specific sequences at their C termini (G16/gust37 and G16/gust44) responded to different T2R receptors with known ligands, but G16/gust 23, G16/gust11, and G16/gust5 did not. The former two chimeras contained a predicted beta6 sheet, an alpha5 helix, and an extreme C terminus of gustducin, and all the domains were indispensable to the expression of T2R activity. We also expressed G16 protein chimeras with the corresponding domain from other Galpha(i) proteins, cone-transducin (Galpha(t2)), Galpha(i2), and Galpha(z) (G16/t2, G16/i2, and G16/z). As a result, G16/t2 and G16/i2 produced specific responses of T2Rs, but G16/z did not. Because Galpha(t2) and Galpha(i2) are expressed in the taste receptor cells, these G-protein alpha(i) subunits may also be involved in bitter taste perception via T2R receptors. The present Galpha16-based chimeras could be useful tools to analyze the functions of many orphan G-protein-coupled taste receptors.

Amino Acid Sequence↗
PubMed2003

Amiloride-insensitive currents of the acid-sensing ion channel-2a (ASIC2a)/ASIC2b heteromeric sour-taste receptor channel.

Acid-sensing ion channel-2a (ASIC2a) is an amiloride-blockable proton-gated cation channel, probably contributing to sour-taste detection in rat taste cells. To isolate another subtype of the sour-taste receptor, we screened a rat circumvallate papilla cDNA library and identified ASIC2b, an N-terminal splice variant of ASIC2a. Reverse transcription-PCR analyses confirmed the expression of ASIC2b transcripts in the circumvallate papilla and, moreover, demonstrated its expression in the foliate and fungiform papillae. Immunohistochemical analyses revealed that ASIC2b, as well as ASIC2a, was expressed in a subpopulation of taste cells in the circumvallate, foliate, and fungiform papillae, and some of the cells displayed both ASIC2a and ASIC2b immunoreactivities. Subsequent coimmunoprecipitation studies with circumvallate papillae extracts indicated that ASIC2b associated with ASIC2a to form assemblies and, together with our immunohistochemical findings, strongly suggested that both ASIC2 subunits formed heteromeric channels in taste cells in the circumvallate, foliate, and fungiform papillae. Oocyte electrophysiology demonstrated that the ASIC2a/ASIC2b channel generated maximal inward currents at a pH of < or =2.0, which is in agreement with the in vivo pH sensitivity of rat taste cells, and that the amiloride sensitivity of the heteromer decreased with decreasing pH and was almost completely abolished at a pH of 2.0. These findings provide persuasive explanations for the amiloride insensitivity of acid-induced responses of rat taste cells.

Acid Sensing Ion Channels↗
PubMed2003

The Arabidopsis GNOM ARF-GEF mediates endosomal recycling, auxin transport, and auxin-dependent plant growth.

Exchange factors for ARF GTPases (ARF-GEFs) regulate vesicle trafficking in a variety of organisms. The Arabidopsis protein GNOM is a brefeldin A (BFA) sensitive ARF-GEF that is required for the proper polar localization of PIN1, a candidate transporter of the plant hormone auxin. Mutations in GNOM lead to developmental defects that resemble those caused by interfering with auxin transport. Both PIN1 localization and auxin transport are also sensitive to BFA. In this paper, we show that GNOM localizes to endosomes and is required for their structural integrity. We engineered a BFA-resistant version of GNOM. In plants harboring this fully functional GNOM variant, PIN1 localization and auxin transport are no longer sensitive to BFA, while trafficking of other proteins is still affected by the drug. Our results demonstrate that GNOM is required for the recycling of auxin transport components and suggest that ARF-GEFs regulate specific endosomal trafficking pathways.

Amino Acid Sequence↗
PubMed2003

A novel putative M9.2 isoform of V-ATPase expressed in the nervous system.

We have identified a cDNA encoding a novel putative neuron-specific isoform of vacuolar proton-translocating ATPase (V-ATPase), NM9.2, from rat and mouse. Sequence analysis revealed that NM9.2 conserved similar characteristic amino acid sequences with 60-70% identity to M9.2 previously isolated from V-ATPase in chromaffin granules. Using Northern blot analysis, NM9.2 mRNA was specifically detected in the brain, whereas M9.2 mRNA was widely expressed in various tissues. In situ hybridization showed that NM9.2 gene expression was restricted mainly to neuronal cells and consistent with that of the a1/Ac116 subunit of V-ATPase. NM9.2 is a putative neuronal isoform of the 9.2 kDa subunit in V-ATPase.

Amino Acid Sequence↗
PubMed2003

Carcinoembryonic antigen mRNA in the mesenteric vein is not a predictor of hepatic metastasis in patients with resectable colorectal cancer: a long-term study.

PURPOSE: The clinical value of carcinoembryonic antigen messenger ribonucleic acid in the draining venous blood has been controversial because of short observation period. The authors prospectively investigated the clinical significance of detection of carcinoembryonic antigen messenger ribonucleic acid in the draining venous blood to predict hepatic metastases in patients with resectable colorectal cancer. METHODS: Drainage venous blood from 80 patients who underwent curative resections for colorectal cancer were obtained immediately before surgery to determine the presence of cancer cells by means of reverse transcription polymerase chain reaction. RESULTS: After an average follow-up period of 52.1 months, 7 of the 35 patients (20 percent) with positive carcinoembryonic antigen messenger ribonucleic acid had hepatic metastases, whereas 2 of the 45 patients (4.5 percent) with negative carcinoembryonic antigen messenger ribonucleic acid had hepatic metastases. The cumulative probability of hepatic metastatic recurrence rate differed significantly between two patient groups with positive or negative carcinoembryonic antigen messenger ribonucleic acid expression in the drainage vein (log-rank, 4.900; P = 0.0269). However, 28 of the 35 patients (80 percent) with positive carcinoembryonic antigen messenger ribonucleic acid did not have hepatic metastases. Additionally, Cox proportional hazards models identified the presence of lymph node metastases as the only independent predictor of hepatic metastatic recurrence. CONCLUSIONS: This study failed to demonstrate the high predictive value of carcinoembryonic antigen messenger ribonucleic acid detection in the draining venous blood for the development of hepatic metastases. However, the authors demonstrated that the presence of cancer cells in the draining venous blood was the essential and initial step to the development of hepatic metastasis.

Aged↗
PubMed2003

Surgery for cardiomyopathy with mitral regurgitation and dyssynchrony.

We present a case of dilated cardiomyopathy with medically intractable congestive heart failure, which was improved by surgical intervention including mitral valve repair and biventricular pacing. This strategy is effective against dilated cardiomyopathy with interventricular dyssynchrony and mitral regurgitation.

Aged↗