Biomedical subjects

Yuji Takeda

Publications and source records attributed to Yuji Takeda.

At least 19 recordsLinked to original sources

PubMed2006

Effect of previously fixated locations on saccade trajectory during free visual search.

Recent studies have shown that the saccade trajectory often curved away from an object that was previously attended but irrelevant to the current saccade goal. We investigated whether such curved saccades occur during serial visual search, which requires sequential saccades possibly controlled by inhibition to multiple locations. The results show that the saccade trajectories were affected by at least three previous fixations. Furthermore, the effect of the previous fixations on saccade trajectories decreased exponentially with time or the number of intervening saccades. The relationship between the curved saccade trajectory and inhibition of return during serial visual search was discussed.

Adult↗

PubMed2006

An inter-item similarity model unifying feature and conjunction search.

We propose a model of visual search to address the hitherto unresolved issue of reconciling serial deployment of attention accounts with inter-item similarity effects. Target-distractor and distractor-distractor similarity were systematically varied in 85 (17x5) set type-size conditions over seven experiments, including univariate feature and bivariate conjunction search. The model, a power (square root) function of dimension-specific target-distractor and distractor-distractor similarity in linear combination with set size, accounted for 98% of the variance on type-size means. It suggests that much of efficient and inefficient search can be unified under a single theory involving item similarity.

Adult↗

PubMed2006

Clinical response is associated with elevated plasma interleukin-1 receptor antagonist during selective granulocyte and monocyte apheresis in patients with ulcerative colitis.

Depletion of granulocytes and monocytes (GM) by selective apheresis (GMA) with an Adacolumn exerts an anti-inflammatory effect in patients with ulcerative colitis (UC) or rheumatoid arthritis. However, the mechanism of the anti-inflammatory effect of GMA is not fully understood yet. We investigated the effect of GMA on the plasma concentration of interleukin-1 receptor antagonist (IL-1ra), a potent anti-inflammatory cytokine. Twenty-six patients with active UC received GMA at one session per week for 5 consecutive weeks. Clinical response was defined as Deltaclinical activity index (DeltaCAI=CAI at entry - CAI at post)>or=4, while clinical remission was defined as CAI<or=4. Twenty-one of twenty-six patients (80.8%) responded to GMA. In the first session, plasma from responder patients showed a significant (P < 0.01) increase in IL-1ra in the Adacolumn outflow. In contrast, there was no change in IL-1ra in nonresponders. In conclusion, release of IL-1ra during GMA might be one mechanism of clinical efficacy associated with this therapy.

Adolescent↗

PubMed2006

Complement activation is involved in biological responses to leukocyte adsorptive apheresis.

We examined the effects of complement activation on the biological responses of cellulose acetate (CA) beads. Peripheral blood containing the complement activation inhibitor nafamostat mesilate (NM) or heparin was incubated with CA beads in vitro. Thereafter, the fraction of adsorbed granulocytes as well as the generation of complement activation fragments (C3a and C5a) and interleukin 1 receptor antagonist (IL-1ra) were measured. Granulocyte adsorption, complement activation, and IL-1ra release were significantly inhibited in the presence of NM. Adsorption was significantly increased onto CA beads pretreated with plasma containing heparin even in the presence of NM and adding C3a or C5a enhanced IL-1ra release. These results suggested that bound complement fragment (e.g., C3b) on CA beads plays a central role in granulocyte adsorption to CA beads and that C3a and C5a augment the release of anti-inflammatory substances. We therefore conclude that complement activation is involved in these biological responses of leukocyte apheresis.

Adsorption↗

PubMed2006

Stent-induced neutrophil activation is associated with an oxidative burst in the inflammatory process, leading to neointimal thickening.

Activation of leukocytes plays an essential role in the mechanism of restenosis. Prior research has focused on monocytes and little is known about the role of neutrophils in this process. Neutrophils are known to contribute to tissue injury through oxygen-derived free radicals that nitrate tyrosine. This study was designed to elucidate clinically the role of neutrophil-mediated oxidative burst in the regulation of the post-stent inflammatory process. In 36 patients undergoing coronary stenting, we serially measured serum levels of glycosyl-phosphatidil-inositol-anchored protein (GPI)-80,a modulator of Mac-1 on the surface of neutrophils, in samples of coronary sinus as well as peripheral blood. We also simultaneously measured the serum 3-nitrotyrosine/tyrosine ratio as an index of oxidative stress. The GPI-80 level and the 3-nitrotyrosine/tyrosine ratio increased in the coronary sinus after coronary stenting in a time-dependent manner; with the maximum increase of GPI-80 level (3.1 +/- 2.9 to 8.6 +/- 4.3 ng/ml, P < 0.01) at 48 hours, and 3-nitrotyrosine/tyrosine ratio at 24 hrs (5.2 +/- 4.8 to 28.4 +/- 13.2 x 10(-4), P < 0.01), more strikingly than in the peripheral blood. In the coronary sinus blood, the 3-nitrotyrosine/tyrosine ratio was correlated with GPI-80 levels at 24 hr (R = 0.58, P < 0.001) and at 48 hr (R = 0.41, P < 0.01). Multiple regressions analysis showed that the maximum responses of GPI-80 level and 3-nitrotyrosine/tyrosine ratio were independent predictors of angiographic late lumen loss. Our results may support a hypothesis that Mac-1-dependent activation of neutrophils causes oxidative burst in the post-stent inflammatory process, possibly leading to restenosis.

Amidohydrolases↗

PubMed2005

Adacolumn for selective leukocytapheresis as a non-pharmacological treatment for patients with disorders of the immune system: an adjunct or an alternative to drug therapy?

Inflammatory and/or autoimmune diseases like ulcerative colitis (UC) or Crohn's disease (CD) are debilitating chronic disorders that poorly respond to pharmacological interventions. Further, drug therapy has adverse effects that add to disease complications. The current thinking is that disorders like inflammatory bowel disease (IBD) reflect an over exuberant immune activation driven by cytokines including TNF-alpha. Major sources of cytokines include myeloid leukocytes (granulocytes, monocytes/macrophages), which in IBD are elevated with activation behavior and are found in vast numbers within the inflamed intestinal mucosa. Accordingly, myeloid cells should be the targets of therapy. Adacolumn is filled with cellulose acetate beads that selectively adsorb and deplete myeloid cells and a small fraction of lymphocytes (FcgammaR and complement receptors bearing cells). In one study, 20 steroid naive patients with moderate (n = 14) or severe (n = 6) UC according to Rachmilewitz despite 1.5-2.25 g/day of 5-aminosalicylic acid received 6 to 10 Adacolumn sessions at 2 sessions/week. Efficacy was assessed 1 week after the last session. The majority of patients responded to 6 sessions, 17 (85%) achieved remission. In 2 of the 3 non-responders, CAI was 8 and 12 in 1; all 3 had deep colonic ulcers at study initiation. Decreases were seen in total leukocytes (P = 0.003), % neutrophils (P = 0.003), % monocytes (P = 0.004), an increase in lymphocytes (P = 0.001), decreases in C-reactive protein (P = 0.0002), and rises in blood levels of soluble TNF-alpha receptors I (P = 0.0007), II (P = 0.0045). In a separate study, a case with very severe steroid refractory UC who received up to 11 sessions responded well and avoided colectomy. Further, myeloid cell purging with Adacolumn has been associated with the release of IL-1 receptor antagonist, suppression of TNF-alpha, IL-1beta, IL-6, IL-8, down-modulation of L-selectin and the chemokine receptor CXCR3. In conclusion, selective depletion of myeloid cells appears to induce anti-inflammatory effects and represents a non-pharmacological treatment for patients with active IBD. The treatment has a clear drug-sparing role. Changes in blood levels of inflammatory and anti-inflammatory factors are thought to contribute to the efficacy of this procedure.

Autoimmune Diseases↗

PubMed2005

Malignant fibrous histiocytoma of the trachea.

We experienced a rare case of malignant fibrous histiocytoma (MFH) arising in the trachea. A 24-year-old man with severe dyspnea had a well-defined mass in the cervical trachea on chest X-ray examination. Chest computed tomography showed a 2.0-cm diameter mass originating in the right-posterior wall of the trachea. The tumor occupied over 90% of the lumen. A radical excision of the tumor (tracheal resection) with tracheal plasty was performed. The microscopic diagnosis was MFH. The patient remains well, without evidence of recurrence, 3 months after surgery.

Adult↗

PubMed2005

Surgical treatment for coronary artery aneurysm.

Two successful cases of the surgical treatment for coronary artery aneurysm (non-Kawasaki disease) were reported. The first case had a saccular aneurysm on the left circumflex coronary artery (LCx) #14. Resection of the LCx aneurysm was performed subsequent to single vessel coronary artery bypass grafting (CABG) to the distal portion of LCx#14 under the cardioplegic cardiac arrest. The second case had aneurysms on both the left anterior descending artery (LAD) #7 (fusiform) and the LCx#11 (saccular). After double vessel CABG to LAD#7 and LCx#11, ligation or resection of two aneurysms was performed successfully. Postoperative courses have been uneventful with good angiographic results achieved. Since these surgical procedures demonstrated safety, the patients are expected to achieve a good long-term prognosis.

Aged↗

PubMed2005

Inhibition of cell spreading in CHO cells transfected with cDNA of a glycosylphosphatidyl inositol-anchored protein, GPI-80.

We have previously cloned a glycosylphosphatidyl inositol (GPI)-anchored protein, designated GPI-80 that associated with integrin and may modulate leukocyte adherence and migration. Recent studies have shown that GPI-80 belongs to a Vanin family that is related to pantetheinase, but the regulatory function of GPI-80 in cell adherence is still unclear. To clarify the possible functions of GPI-80, we transfected GPI-80 cDNA into Chinese hamster ovary (CHO) cells and observed adherence and morphological changes. Adherence of GPI-80 transfectants was significantly decreased when signal strength for the cell adhesion is weak, and the cell spreading of the transfectants was strongly inhibited. This inhibitory effect of GPI-80 expression was largely canceled by GPI-80 shedding with phosphatidy-linositol-specific phospholipase C. Interestingly, spreading of GPI-80 transfectants was temporarily recovered from the round shape but not maintained by stimulation with known activators of beta1 integrins, phorbol myristate acetate and manganese ions. Taken together, these results suggest that the expression of GPI-80 on CHO cells can influence cell spreading in weak adhesive signal conditions via extracellular matrix molecules.

Amidohydrolases↗

PubMed2005

Use of spatial context is restricted by relative position in implicit learning.

For inefficient search, target detection is faster for repeated than for regenerated layouts. This effect, called contextual cuing, was assumed to arise from implicit learning of local spatial relationships between targets and distractors. However, a more global influence from distractors far from the target has not been tested. In this study, the search field was divided into upper and lower halves containing a repeated and a regenerated configuration set, respectively. The positions of the two sets were or were not exchanged, meaning that their relative as well as their absolute positions were the same or different (Experiment 1). In Experiment 2, the repeated set appeared alone in either the same or the other half of the screen (same or different absolute position). The contextual cuing effect remained when only absolute position was changed, but not when both absolute and relative positions were changed. These results suggest that contextual cuing depends on relative positional information.

Adult↗

PubMed2005

[Different impacts of DMSO and RA on GPI-80 expression].

Our previous studies suggested that GPI-80 expression might be associated with myeloid differentiation. Dimethyl sulfoxide (DMSO) and all-trans-retinoic acid (RA) are two main inducers that can induce HL-60 cell to differentiate down the way of neutrophilic lineage. GPI-80 is a novel member of a human glycosylphosphatidylinositol (GPI)-anchored family that has been proposed as a potential regulator of beta2-integrin-dependent leukocyte adhesion, and is expressed mainly in human neutrophils. RT-PCR, flow cytometry and western-blot assays were used to detect the GPI-80 expression on HL-60 cells induced by DMSO or RA and to analyze the relationship between GPI-80 expression and CD11b or transferrin receptor (CD71) expression. The results showed GPI-80 was slightly expressed on the level of mRNA on RA-induced HL-60 cells by RT-PCR, while using flow cytometry and western-blot assays, We could not detect any GPI-80 expression on these cells, Furthermore, RA suppressed the induction of GPI-80 expression. However, DMSO could clearly derive the GPI-80 expression and this expression correlated well with the increasing dose and duration of DMSO stimulation. GPI-80 positive cells, which were included in CD11b-strongly positive and transferrin receptor-completely negative populations, were sufficiently differentiated cells suggesting that GPI-80 expression is tightly associated with the neutrophilic maturation and can be used as a mature neutrophilic marker. RA inhibits the GPI-80 expression on DMSO induced HL-60 cells suggests that different signal conduction has been activated by DMSO and RA when they induce the HL-60 cells to the neutrophilic differentiation.

Antigens, CD↗

PubMed2004

Carcinoembryonic antigen as a predictive factor for postoperative tumor relapse in early-stage lung adenocarcinoma.

OBJECTIVES: To clarify the usefulness of measuring serum carcinoembryonic antigen (CEA) preoperatively to detect patients who will have a poor outcome after surgery, and who cannot be selected by conventional staging modalities. METHODS: One hundred patients with adenocarcinoma of the lung underwent standard surgical procedures between 1994 and April 2001 at our institution. Preoperative staging was assessed according to the TNM classification of the International Union Against Cancer. The associations between preoperative serum CEA level and the postoperative recurrence or lymph node metastasis were examined. The serum CEA level was classified into two groups according to concentration of CEA level: low (normal) CEA ( 5.0 ng/ml). RESULTS: The high CEA level was associated with tumor relapse (P=0.01). According to the preoperative staging, the increased CEA was associated with tumor relapse only in stage C-IA (P=0.001). Stage C-IB and more advanced stages did not show an association between increased CEA and tumor relapse. In C-IA, risk for lymph node involvement was significantly higher in the high CEA group (4/9; 44.4%) than in the low CEA group (6/47; 12.8%, P=0.03). Furthermore, the rate of tumor relapse in C-IA-pN0 was significantly higher in the high CEA group (4 of the 5, 80%) than in the low CEA group (9 of the 41, 22.0%, P=0.018). The 5-year disease-free survival rate for patients with a high serum CEA level (N=9) was 22.2%, and 75.0% for patients with a normal CEA (N=47) level (P=0.0004). CONCLUSIONS: Increased serum CEA is an important predictive factor for poor outcome after surgery in early-stage (C-IA) lung adenocarcinoma.

Adenocarcinoma↗

PubMed2004

Lung adenocarcinoma can be subtyped according to tumor dimension by computed tomography mediastinal-window setting. Additional size criteria for clinical T1 adenocarcinoma.

OBJECTIVE: We sought to verify that the size of the solid component, which can be evaluated using the computed tomography mediastinal-window setting, provides new criteria for CT classification of lung adenocarcinoma. METHODS: Between 1994 and September 2002, we examined 60 patients who were clinically classified with stage T1 adenocarcinoma of the lung and normal serum CEA, who underwent standard surgical procedures. Tumor maximum dimension was evaluated using two different CT-imaging settings: the lung window (lDmax), and the mediastinal window (mDmax). We analyzed the relationships between prognosis or lymph node involvement and tumor dimensions. RESULTS: The mDmax was a significant (OR 1.11, P=0.02) predictive factor for lymph node metastasis. However, lDmax was not significant (P=0.83). Age, gender, lDmax, mDmax, and lymph node involvement were analyzed as predictive factors for prognosis. In univariate analysis, mDmax and lymph node involvement were significant predictive factors for prognosis (OR 1.07, P=0.01; OR 2.56, P=0.04; respectively). In multivariate analysis, mDmax was a significant predictive factor for prognosis (OR 1.06, P=0.04). We then classified the C-T1 adenocarcinoma patients into three groups according to mDmax: T1a (< or =10 mm), T1b (from 11 to 20 mm), and T1c (from 21 to 30 mm). There was a significant difference between the three groups: the disease-free 5-year survivals were 93.3, 58.1, and 32.7%, respectively (P=0.01). CONCLUSIONS: The mDmax can give additional, useful prognostic data. This finding may provide new criteria for CT classification of lung adenocarcinoma.

Adenocarcinoma↗

PubMed2004

Molecular proximity of complement receptor type 3 (CR3) and the glycosylphosphatidylinositol-linked protein GPI-80 on neutrophils: effects of cell adherence, exogenous saccharides, and lipid raft disrupting agents.

GPI-80, a novel glycosylphosphatidylinositol (GPI)-anchored protein on polymorphonuclear leukocytes, has been reported to cooperate with CR3 in several aspects of cell function including cell activation, adhesion and migration. The present study investigates the physical proximity of CR3 and GPI-80 on living cells using resonance energy transfer (RET) techniques, which gives positive results when the separation distance is < or = 7 nm. RET from donor-labeled anti-CR3 to acceptor-labeled anti-GPI-80 was detected on adherent neutrophils, but not observed for non-adherent cells. Furthermore, RET was not observed on cells treated with cell adhesion inhibitors 4-bromophenacyl bromide (BPB), N-ethylmaleimide (NEM) or cytochalasin D, suggesting dynamic interactions between CR3 and GPI-80. CR3-to-GPI-80 proximity was blocked by N-acetyl-D-glucosamine (NADG), but not by other monosaccharides such as D-mannose, fructose, fucose, glucose, sorbitol, or galactose; molecular proximity was also disrupted by the glycolipid raft depleting agents 2-OH-propyl-betaCD and MbetaCD. Thus, lipid rafts may be important for the physical and functional cooperation of CR3 and GPI-80.

Acetylglucosamine↗

PubMed2004

Visual search and memory search engage extensive overlapping cerebral cortices: an fMRI study.

Previous studies have investigated neural correlates of visual search and memory search independently, but none of those studies examined whether cortical regions involved in these searches are overlapping or segregated by directly comparing the two types of search. In this study, we compared the cortical regions involved in visual search and memory search in the same functional magnetic resonance imaging (fMRI) experiment run on the same subjects, using identical stimuli and time courses of stimulus presentation. The right dorsolateral prefrontal cortex (DLPFC), the left frontal eye field (FEF), the right precuneus and cuneus, and the left cerebellum were activated by both visual search and memory search. We suggest that the right DLPFC is associated with the process of monitoring and manipulating multiple elements, while the left FEF is involved in cognitive planning. We also propose that the right precuneus and cuneus as well as the left cerebellum are responsible for both spatial and nonspatial shifts of attention, including attentional shifts in long-term memory, although each of these regions has a slightly different role.

Adult↗

PubMed2004

Video-assisted bronchial stump reinforcement with an intercostal muscle flap.

For lobectomy patients at considerable risk of developing a postoperative bronchopleural fistula, the bronchial stump reinforcement with an intercostal muscle flap is sometimes performed. This procedure usually requires a standard thoracotomy, even if video-assisted thoracoscopic surgery (VATS) is better for the patient. Our patient was a 76-year-old male with lung cancer and severe diabetes mellitus. He underwent lobectomy and systematic nodal dissection combined with bronchial stump reinforcement using an intercostal muscle flap, performed as a VATS procedure. No postoperative complications were observed. This procedure is applicable to patients who are candidates for VATS lobectomy.

Aged↗

PubMed2004

Selective learning of spatial configuration and object identity in visual search.

To conduct an efficient visual search, visual attention must be guided to a target appropriately. Previous studies have suggested that attention can be quickly guided to a target when the spatial configurations of search objects or the object identities have been repeated. This phenomenon is termed contextual cuing. In this study, we investigated the effect of learning spatial configurations, object identities, and a combination of both configurations and identities on visual search. The results indicated that participants could learn the contexts of spatial configurations, but not of object identities, even when both configurations and identities were completely correlated (Experiment 1). On the other hand, when only object identities were repeated, an effect of identity learning could be observed (Experiment 2). Furthermore, an additive effect of configuration learning and identity learning was observed when, in some trials, each context was the relevant cue for predicting the target (Experiment 3). Participants could learn only the context that was associated with target location (Experiment 4). These findings indicate that when multiple contexts are redundant, contextual learning occurs selectively, depending on the predictability of the target location.

Adult↗

PubMed2004

Search for multiple targets: evidence for memory-based control of attention.

There are two opposing models with regard to the function of memory in visual search: a memory-driven model and a memory-free model. Recently, Horowitz and Wolfe (2001) investigated a multiple-target search task. Participants were required to decide whether or not there were at least n targets present. They demonstrated that the reaction time x n function has a positive and accelerated curve. They argued that the memory-free model predicts this curve, whereas the memory-driven model predicts a linear function. In this study, I varied the total set sizes of a multiple-target search task and fitted the models separately for each n condition. The model fit indicated that the memory-driven model is more appropriate than the memory-free model in each n condition. These results suggest that an amnesic process does not cause the positive accelerated curve of the reaction time x n function but that it is the result of the time needed to examine each additional n item.

Adolescent↗