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Biomedical subjects

Takashi Ueda

Publications and source records attributed to Takashi Ueda.

At least 73 records · Page 4Linked to original sources
PubMed2003

Does skeletonization compromise the integrity of internal thoracic artery grafts?

BACKGROUND: There are few reports that demonstrate the chronologic changes in the functional integrity of the internal thoracic artery (ITA) wall after skeletonization. We investigated the impact of skeletonization on ITA wall integrity by immunohistochemical analyses in acute and chronic phases. METHODS: Nine mongrel dogs underwent bilateral ITA dissection with one skeletonized vessel and the other pedicled. The following studies were performed 1 week (acute phase, n = 3) and 12 weeks (chronic phase, n = 6) after ITA harvesting. All specimens of the ITAs were stained by antibodies against von Willebrand Factor (VWF), endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), and proliferating cell nuclear antigen (PCNA). After observation with confocal laser scanning microscopy, quantitative analyses of the staining signal for VWF and eNOS expressed on endothelial cells were performed. RESULTS: There were significantly more microvessels positive for VWF in the adventitia of skeletonized ITAs than in the adventitia of pedicled ITAs but the expression of PCNA in both groups was minimal, as in normal vessels. iNOS was not detected in any specimen. The intensity of VWF and eNOS expressed by endothelial cells had no significant differences between groups at either phase. CONCLUSIONS: The functional integrity of skeletonized ITA was similar to that of pedicled ITA in both acute and chronic phases. Although skeletonization induced neovascularization in the adventitia it did not induce proliferation of smooth muscle cells in the media, which is supposed to be a feature of vascular remodeling.

Animals↗
PubMed2003

Concomitant transabdominal MIDCAB and abdominal aortic aneurysm repair.

We present 2 patients who underwent transabdominal minimally invasive direct coronary artery bypass with the right gastroepiploic artery combined with abdominal aortic aneurysm repair. The surgical procedures, both performed through a median laparotomy, proved safe and of limited invasiveness. The one-stage surgical intervention prevented catastrophic complications, such as acute myocardial infarction or rupture of abdominal aortic aneurysm. We believe that concomitant transabdominal minimally invasive direct coronary artery bypass and abdominal aortic aneurysm repair should be considered as a single combined surgical strategy in selected patients.

Aged↗
PubMed2003

Pancreatic duct obstruction itself induces expression of alpha smooth muscle actin in pancreatic stellate cells.

BACKGROUND: Pancreatic stellate cells (PSCs) are thought to be responsible for pancreatic fibrosis. Although fibrosis is a major characteristic of chronic pancreatitis (CP) induced by pancreatic duct obstruction, it is unclear whether pancreatic duct obstruction itself activates PSCs. METHODS: To test the hypothesis that pancreatic duct obstruction activates PSCs, clinical and experimental analyses were performed using alpha smooth muscle actin (alpha-SMA) as a marker of their activation. In clinical analysis, surgical specimens from the patients with pancreatic cancer or cancer of the papilla Vater were classified into two groups with or without duct obstruction. alpha-SMA expression was examined on these specimens, and the difference between two groups was evaluated. In animal experiment, duct ligation-induced pancreatitis was developed in rats by ligating the secondary pancreatic duct in duodenal segment, and the expression of alpha-SMA was examined. RESULTS: In clinical analysis, the specimens from the pancreas with duct obstruction (14 cases) expressed alpha-SMA significantly stronger than those from the pancreas without duct obstruction (7 cases). All specimens in the former expressed alpha-SMA, but 4 specimens from the latter did not at all (P < 0.05). In animal experiment, alpha-SMA expression was detected 7 days after the ligation and was increased on the 10th day. CONCLUSIONS: We can assume that pancreatic duct obstruction itself activates PSCs. This mechanism may play roles in the development of CP from multiple origins.

Actins↗
PubMed2003

Cdc50p, a conserved endosomal membrane protein, controls polarized growth in Saccharomyces cerevisiae.

During the cell cycle of the yeast Saccharomyces cerevisiae, the actin cytoskeleton and the growth of cell surface are polarized, mediating bud emergence, bud growth, and cytokinesis. We identified CDC50 as a multicopy suppressor of the myo3 myo5-360 temperature-sensitive mutant, which is defective in organization of cortical actin patches. The cdc50 null mutant showed cold-sensitive cell cycle arrest with a small bud as reported previously. Cortical actin patches and Myo5p, which are normally localized to polarization sites, were depolarized in the cdc50 mutant. Furthermore, actin cables disappeared, and Bni1p and Gic1p, effectors of the Cdc42p small GTPase, were mislocalized in the cdc50 mutant. As predicted by its amino acid sequence, Cdc50p appears to be a transmembrane protein because it was solubilized from the membranes by detergent treatment. Cdc50p colocalized with Vps21p in endosomal compartments and was also localized to the class E compartment in the vps27 mutant. The cdc50 mutant showed defects in a late stage of endocytosis but not in the internalization step. It showed, however, only modest defects in vacuolar protein sorting. Our results indicate that Cdc50p is a novel endosomal protein that regulates polarized cell growth.

Actins↗
PubMed2003

Improvement of cerebral blood flow by olprinone, a phosphodiesterase-3 inhibitor, in mild heart failure.

Cerebral blood flow (CBF) is reduced in heart failure (HF). For the treatment of acute HF, a phosphodiesterase-3 inhibitor, olprinone (OL), yields an increase in myocardial contractility and a decrease in arterial afterload. During a 15-min intravenous infusion of OL (0.2 microg/kg/min), regional CBF at 6 sites of each cerebral cortex was examined using technetium-99m-ethylcysteinate dimer brain SPECT in 18 HF patients and 7 age-matched normal subjects. The baseline CBF was significantly reduced in HF (43.0 +/- 3.9 ml/min/100 g) compared to that in normal subjects (48.0 +/- 4.6 ml/min/100 g, p < 0.01). The baseline CBF showed a significant negative correlation with the increase in CBF during the OL infusion in HF (r = -0.38, p < 0.01) and normal subjects (r = -0.65, p < 0.01). The percent increase in CBF was significantly greater in HF (13.7%) than in normal subjects (9.8%, p < 0.046). In patients with HF, the CBF of the cerebral cortex was decreased, but was increased by OL infusion.

Aged↗
PubMed2003

Upregulation of P-selectin and intercellular adhesion molecule-1 after retinal ischemia-reperfusion injury.

PURPOSE: Vascular endothelial cells and leukocytes express several inflammatory adhesion receptors, such as selectins and cell adhesion molecules, after retinal ischemia. They mediate the transmigration process of leukocytes. For further understanding of the role of leukocytes after retinal ischemia-reperfusion injury, the responses of the leukocyte-endothelial cell adhesion molecules P-selectin and intercellular adhesion molecule (ICAM)-1 during retinal ischemia and reperfusion were examined. METHODS: Male pigmented rats were subjected to retinal ischemia by a 1-hour ligation of the optic nerve followed by reperfusion. Gene and protein expression of P-selectin and ICAM-1 were studied at 0.5, 1, 6, 12, and 24 hours after the onset of reperfusion with semiquantitative polymerase chain reaction and Western blot analysis. Immunohistochemical methods were used to detect specific lesions expressing ICAM-1. RESULTS: Significant upregulation of P-selectin and ICAM-1 mRNA (at 6, 12, and 24 hours of reperfusion) were observed, with the expression peaks of both P-selectin and ICAM-1 mRNA occurring at 12 hours after reperfusion. P-selectin protein gradually increased and reached a maximum 6 hours after reperfusion, whereas ICAM-1 protein increased until 24 hours after reperfusion. Immunostaining with ICAM-1 antibodies was positive in endothelial cells after ischemia-reperfusion injury. CONCLUSIONS: Retinal ischemia-reperfusion stimulates P-selectin and ICAM-1 expression. Endothelial ICAM-1 expression in retinal vessels was observed. Upregulation of P-selectin and ICAM-1, which contribute to leukocyte rolling and adhesion, were observed after retinal ischemia.

Animals↗
PubMed2003

[Fundamental study of the relation between flow velocity and signal intensity in the TrueFISP sequence].

The purpose of this study was to evaluate the effect of inflow phenomenon on TrueFISP. We created a phantom using a vinyl tube and distilled water, and applied a pump-oxygenator to the phantom to obtain stationary flow. First, to evaluate the effect of inflow and the dephase phenomenon on signal intensity, the phantom was measured for the signal intensity of variable flow velocity. Second, the relation of TR/TE with signal intensity was analyzed. The results showed that a flow velocity of less than 15 cm/sec did not participate in signal reduction; however, signal intensity was reduced when flow velocity was more than 30 cm/sec. Moreover, the reduction of signal intensity was remarkable with a flow velocity of 50-100 cm/sec, which corresponds with arterial flow velocity. In the analysis of TR/TE, signal intensity was increased when TR of less than 5 ms was applied to the slow velocity of 15 cm/sec. Signal intensity was decreased when the same TR was applied to the high velocity of 50-100 cm/sec. When TR was 6-9 ms, peak signal intensity was recognized at the high velocity of 50-100 cm/sec. This peak, however, might correspond only to the inflow phenomenon, and steady state might have already collapsed. Based on these results, we concluded that TrueFISP is suitable for the imaging of slow flow velocity. A short TR of less than 5 ms was effective for obtaining high signal intensity. Our next goal will be to apply TrueFISP to MR venography, although further investigation will be necessary.

Blood Flow Velocity↗
PubMed2003

[Usefulness of 3D-VIBE method in breast dynamic MRI: imaging parameters and contrasting effects].

MR imaging (MRI) has been reported to be a useful modality to characterize breast tumors and to evaluate disease extent. Contrast-enhanced dynamic MRI, in particular, allows breast lesions to be characterized with high sensitivity and specificity. Our study was designed to develop three-dimensional volumetric interpolated breath-hold examination (3D-VIBE) techniques for the evaluation of breast tumors. First, agarose/Gd-DTPA phantoms with various concentrations of Gd-DTPA were imaged using 3D-VIBE and turbo spin echo (TSE). Second, one of the phantoms was imaged with 3D-VIBE using different flip angles. Finally, water excitation (WE) and a chemical shift-selective (CHESS) pulse were applied to the images. Each image was analyzed for signal intensity, signal-to-noise ratio (1.25*Ms/Mb) (SNR), and contrast ratio [(Ms1-Ms2)/[(Ms1+Ms2)/2]]. The results showed that 3D-VIBE provided better contrast ratios with a linear fit than TSE, although 3D-VIBE showed a lower SNR. To reach the best contrast ratio, the optimized flip angle was found to be 30 degrees for contrast-enhanced dynamic study. Both WE and CHESS pulses were reliable for obtaining fat-suppressed images. In conclusion, the 3D-VIBE technique can image the entire breast area with high resolution and provide better contrast than TSE. Our phantom study suggests that optimized 3D-VIBE may be useful for the assessment of breast tumors.

Breast Neoplasms↗
PubMed2003

Intraperitoneal administration of oxygenated perfluorochemical inhibits bacterial translocation associated with severe acute pancreatitis.

Bacterial translocation from gut has been assumed to be an infectious source in severe acute pancreatitis. The purpose of this study was to test the effect of intraperitoneal administration of oxygenated perfluorochemical on bacterial translocation associated with rat experimental acute necrotizing pancreatitis. Severe necrotizing pancreatitis was induced by retrograde injection of 3% sodium deoxycholate into the biliopancreatic ducts of male Wistar rats. Although mortality rate was not improved by the treatment, intraperitoneal administration of oxygenated perfluorochemical, perfulorodecalin reduced incidence of bacterial translocation to the mesenteric lymph nodes from 60% to 37% 12 hours after development of pancreatitis, and significantly reduced number of bacterial colonies detected after 24 hours. The treatment did not alter the villous height and crypt depth of the ileum. In this model for pancreatitis, however, accelerated apoptosis of the intestinal epithelium was detected histochemically by TUNEL staining and biochemically by DNA fragmentation ELISA, and the apoptotic changes were significantly suppressed by the treatment. These results indicate that intraperitoneal administration of oxygenated perfluorochemical inhibits apoptosis of intestinal epithelium and bacterial translocation induced in severe acute pancreatitis.

Animals↗
PubMed2003

Feasible pericardiotomy for off-pump coronary artery bypass.

Pericardiotomy is the first essential step for the exposure of the coronary artery in off-pump coronary artery bypass (OPCAB) via a median sternotomy. After the dissection of the pericardium from the pleura, a longitudinal pericardiotomy from the apex to the aortic reflection was employed. The pericardiotomy was extended transversely to make a trapezoidal flap. By the traction of the left pericardium, anterior vessels were well exposed. For the closure, a trapezoidal pericardial flap was useful.

Coronary Artery Bypass↗
PubMed2002

Vanilloid receptor subtype-1 (VR1) is specifically localized to taste papillae.

Pungent sensation of hot peppers is thought to be mediated by vanilloid receptor subtype-1 (VR1), which can be activated by capsaicin, but there is little information regarding its histological localization in the tongue. We examined the immunohistochemical distribution of VR1 in the rat tongue. Intensely labeled VR1-immunoreactive (VR1-IR) fibers were concentrated in the circumvallate, foliate, and fungiform papillae, while sparse VR1-IR fibers were scattered throughout the tongue. VR1-positive taste-bud cells were not observed. Many VR1-positive nerve fibers surrounded the furrows of the circumvallate and foliate papillae, forming plexuses. Some of these VR1-positive fibers penetrated the apical epithelium and the trench wall epithelium, while a few of them entered taste buds. These VR1 distribution patterns resembled those of substance P (SP) and the calcitonin gene-related peptide (CGRP). Double-labeling experiments revealed that most of the VR1-immunoreactivity coexisted with SP- or CGRP-immunoreactivity in the nerve terminals in the circumvallate and foliate papillae. On the other hand, in the fungiform papillae, most of the VR1-IR fibers were positive for SP, but fewer were also positive for CGRP. Although VR1-immunoreactivity was not observed in taste-bud cells, our findings that a large number of VR1-IR fibers concentrated in the taste papillae suggest that capsaicin easily reaches the VR1 nerve terminals because of its lipophilic nature.

Animals↗
PubMed2002

Intracerebral hemorrhage upregulates Na(+)/myo-inositol cotransporter in the rat brain.

We examined the expression of Na(+)/myo-inositol cotransporter (SMIT) in the rat brain after intrastriatal hemorrhage. The expression of SMIT messenger RNA (mRNA) increased around hematoma 3 days after hemorrhage and it returned to control level as hematoma was absorbed. The expression of SMIT mRNA also increased at ipsilateral substantia nigra without blood-brain barrier disruption 7 days after hemorrhage and remained high until 42 days after hemorrhage. Immunohistochemistry revealed that macrophages around hematoma and microglias at ipsilateral substantia nigra were SMIT-positive. These results suggest that the expression of SMIT must be regulated not only by osmolality but also by unknown factors.

Animals↗
PubMed2002

Functional alterations of splenocytes in severe acute pancreatitis.

BACKGROUND AND AIMS: Recently, the concept of "Th1 (T helper cell type 1)/Th2 (T helper cell type 2) balance" was introduced for understanding the pathophysiologic response during septic or preseptic conditions. To clarify unknown Th1/Th2 balance during acute pancreatitis, functional alterations of the splenocyte were investigated in rat experimental severe acute pancreatitis. METHODS: Spleens were removed from rats 24 h after the induction of severe necrotizing pancreatitis by retrograde injection of 3% sodium deoxycholate. Total splenocytes were harvested and cultured in the presence or absence of concanavalin A (con A) for 24 h. Proliferative capacities and cytokine-releasing capacities were evaluated. RESULTS: In splenocytes harvested 24 h after the induction of pancreatitis, proliferative capacity with con A stimulation was significantly lower than that of sham operation. Interleukin-2 (IL-2) release with con A stimulation and interferon-gamma release with or without con A stimulation were significantly decreased in splenocytes from the rats with pancreatitis compared with those from sham operation. Interleukin-10 (IL-10) release with con A stimulation was also significantly decreased in splenocytes from the rats with pancreatitis compared with those from sham operation. The IL-2/IL-10 concentration ratio secreted by the splenocytes from the rats with pancreatitis was significantly lower than that from those undergoing the sham operation. CONCLUSIONS: These results suggest that splenocyte function is markedly suppressed in experimental severe acute pancreatitis and that Th1/Th2 balance tends to Th1 suppression as a whole. Dysfunction of lymphocytes including splenocytes may play a certain role in the development of subsequent septic complications in this disease.

Acute Disease↗
PubMed2002

Vesicular traffic: an integral part of plant life.

Extensive studies on the molecular mechanisms of vesicular traffic have revealed that plants use similar machinery to mammals and fungi for the formation, transport, docking and fusion of vesicles. In addition to conserved components, plant-unique molecules also regulate these phenomena. Recent research has begun to show that the vesicular traffic controlled by these various molecules plays amazing roles in higher-order plant functions, such as tropisms.

Arabidopsis↗
PubMed2002

A complex and mobile structure forms a distinct subregion within the continuous vacuolar membrane in young cotyledons of Arabidopsis.

The plant vacuole is a multifunctional organelle which is essential for growth and development. To visualize the dynamics of plant vacuolar membranes, gamma-TIP (tonoplast intrinsic protein) was fused to GFP and expressed in Arabidopsis thaliana. The marker molecule was targeted to the vacuolar membranes in most tissues, as expected. In rapidly expanding cells, some additional spherical structures were often observed within the lumen of vacuoles, which emitted strong fluorescence. To confirm their normal presence, we examined wild-type Arabidopsis cotyledons by transmission electron microscopy. The metal-contact rapid-freezing method revealed that the vacuolar lumen of epidermal cells contained many cytoplasmic projections, which often formed spherical structures (1-3 microm diameter) consisting of double membranes. Thus we concluded that these structures are authentic and named them 'bulbs'. Three-dimensional reconstruction from serial electron microscopic images demonstrates that bulbs are very intricately folded, but are continuous with the limiting vacuolar membrane. The fluorescence intensity of bulbs is about threefold higher than that of vacuolar membrane. GFP-AtRab75c, another marker of the vacuole, did not give fluorescent signals of bulbs in transgenic plants, but the existence of bulbs was still confirmed by electron microscopy. These results suggest that bulbs define a subregion in the continuous vacuolar membrane, where some proteins are concentrated and others segregated.

Arabidopsis↗
PubMed2002

Arf1 GTPase plays roles in the protein traffic between the endoplasmic reticulum and the Golgi apparatus in tobacco and Arabidopsis cultured cells.

Arf GTPases are known to be key regulators of vesicle budding in various steps of membrane traffic in yeast and animal cells. We cloned the Arabidopsis Arf1 homologue, AtArf1, and examined its function. AtArf1 complements yeast arf1 arf2 mutants and its GFP-fusion is localized to the Golgi apparatus in plant cells like its animal counterpart. The expression of dominant negative mutants of AtArf1 in tobacco and Arabidopsis cultured cells affected the localization of co-expressed GFP-tagged proteins in a variety of ways. AtArf1 Q71L and AtArf1 T31N, GTP- and GDP-fixed mutants, respectively, changed the localization of a cis-Golgi marker, AtErd2-GFP, from the Golgi apparatus to the endoplasmic reticulum but not that of GFP-AtRer1B or GFP-AtSed5. GFP-AtRer1B and GFP-AtSed5 were accumulated in aberrant structures of the Golgi by AtArf1 Q71L. A soluble vacuolar protein, sporamin-GFP, was also located to the ER by AtArf1 Q71L. These results indicate that AtArf1 play roles in the vesicular transport between the ER and the Golgi and in the maintenance of the normal Golgi organization in plant cells.

ADP-Ribosylation Factor 1↗