Biomedical subjects

Yoshihiro Takeda

Publications and source records attributed to Yoshihiro Takeda.

At least 19 recordsLinked to original sources

PubMed2006

Association of coronary plaque composition and arterial remodelling: a virtual histology analysis by intravascular ultrasound.

BACKGROUND: Conflicting data have been reported about the correlation between plaque composition assessed by virtual histology (VH) and remodelling index (RI). AIM: To evaluate, in a larger patient population, the relationship between plaque morphology obtained by VH and arterial remodelling. METHODS AND RESULTS: VH intravascular ultrasound was performed on 95 non-bifurcation native significant lesions (>75% stenosis) in 85 patients. Positive remodelling (defined as RI > or =1.05) was present in 28 lesions, whereas intermediate/negative remodelling (RI <1.05) was present in 67 lesions. Compared with intermediate/negative remodelling, positive remodelling was associated with an increased frequency of patients with acute coronary syndrome (n = 13 (52%) vs n = 15 (25%); p = 0.017), and with a greater plaque burden (mean (SD) 78.3 (6.3)% vs 73.2 (6.8)%, p = 0.001). At the minimal lumen site, necrotic core was significantly smaller in lesions with positive remodelling (median (interquartile range) 5.0% (2.2-11.0%)) than in lesions with intermediate/negative remodelling (median (interquartile range) 9.0% (4.0-16.0%); p = 0.048). No differences were observed in the rate of thin-cap fibroatheroma or in the presence of multiple necrotic core layers, and there were no statistical differences for fibrous, fibro fatty and dense calcium percent plaque area at the minimum lumen diameter (MLD), or for the entire lesion length between both groups. CONCLUSIONS: In vivo VH analysis shows that lesions with positive remodelling have statistically less necrotic core percent area at the MLD site compared with intermediate/negative remodelling lesions.

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PubMed2006

Accuracy of in vivo coronary plaque morphology assessment: a validation study of in vivo virtual histology compared with in vitro histopathology.

OBJECTIVES: The goal of the present study was to compare the accuracy of in vivo tissue characterization obtained by intravascular ultrasound (IVUS) radiofrequency (RF) data analysis, known as Virtual Histology (VH), to the in vitro histopathology of coronary atherosclerotic plaques obtained by directional coronary atherectomy. BACKGROUND: Vulnerable plaque leading to acute coronary syndrome (ACS) has been associated with specific plaque composition, and its characterization is an important clinical focus. METHODS: Virtual histology IVUS images were performed before and after a single debulking cut using directional coronary atherectomy. Debulking region of in vivo histology image was predicted by comparing pre- and post-debulking VH images. Analysis of VH images with the corresponding tissue cross section was performed. RESULTS: Fifteen stable angina pectoris (AP) and 15 ACS patients were enrolled. The results of IVUS RF data analysis correlated well with histopathologic examination (predictive accuracy from all patients data: 87.1% for fibrous, 87.1% for fibro-fatty, 88.3% for necrotic core, and 96.5% for dense calcium regions, respectively). In addition, the frequency of necrotic core was significantly higher in the ACS group than in the stable AP group (in vitro histopathology: 22.6% vs. 12.6%, p = 0.02; in vivo virtual histology: 24.5% vs. 10.4%, p = 0.002). CONCLUSIONS: Correlation of in vivo IVUS RF data analysis with histopathology shows a high accuracy. In vivo IVUS RF data analysis is a useful modality for the classification of different types of coronary components, and may play an important role in the detection of vulnerable plaque.

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PubMed2006

Effective proliferation of low level Legionella pneumophila serogroup 1 cells using coculture procedure with Acanthamoeba castellanii.

The multiplications of low level Legionella pneumophila serogroup 1 cells by the coculture procedure with Acanthamoeba castellanii were tested in five strains. The cells in all strains proliferated effectively for isolating. This procedure might be a useful means of improving the successful isolation from environmental and clinical specimens of low level Legionella cells, and pursuing the source of infection.

Acanthamoeba castellanii↗

PubMed2006

Degradation of protein in nanoplasma generated around gold nanoparticles in solution by laser irradiation.

We developed a method of protein degradation in an aqueous solution containing gold nanoparticles by irradiation of a pulse laser. In the present study, lysozyme was used as an example. Lysozyme degradation proceeded most efficiently when a pH of the solution was adjusted so that it was at the isoelectric point. The scheme of the lysozyme degradation is as follows: (1) Lysozyme molecules in the solution are neutralized and adsorbed on the gold nanoparticles with its pH value adjusted at the isoelectric point, (2) nanoplasma is generated in the close vicinity of a gold nanoparticle which is excited by an intense 532-nm laser, (3) lysozyme molecules in the nanoplasma are degraded into small fragments. Lysozyme degradation does not proceed efficiently at a pH value deviated from the isoelectric point because the lysozyme molecules are dissolved uniformly so that only a small portion of the lysozyme molecules are located in the vicinity of gold nanoparticles which create the nanoplasma.

Gold↗

PubMed2006

Diagnostic accuracy of 64-slice computed tomography for detecting angiographically significant coronary artery stenosis in an unselected consecutive patient population: comparison with conventional invasive angiography.

BACKGROUND: Multislice computed tomography (MSCT) is a promising noninvasive method of detecting coronary artery disease (CAD). However, most data have been obtained in selected series of patients. The purpose of the present study was to investigate the accuracy of 64-slice MSCT (64 MSCT) in daily practice, without any patient selection. METHODS AND RESULTS: Using 64-slice MSCT coronary angiography (CTA), 69 consecutive patients, 39 (57%) of whom had previously undergone stent implantation, were evaluated. The mean heart rate during scan was 72 beats/min, scan time 13.6 s and the amount of contrast media 72 mL. The mean time span between invasive coronary angiography (ICAG) and CTA was 6 days. Significant stenosis was defined as a diameter reduction of > 50%. Of 966 segments, 884 (92%) were assessable. Compared with ICAG, the sensitivity of CTA to diagnose significant stenosis was 90%, specificity 94%, positive predictive value (PPV) 89% and negative predictive value (NPV) 95%. With regard to 58 stented lesions, the sensitivity, specificity, PPV and NPV were 93%, 96%, 87% and 98%, respectively. On the patient-based analysis, the sensitivity, specificity, PPV and NPV of CTA to detect CAD were 98%, 86%, 98% and 86%, respectively. Eighty-two (8%) segments were not assessable because of irregular rhythm, calcification or tachycardia. CONCLUSION: Sixty-four-MSCT has a high accuracy for the detection of significant CAD in an unselected patient population and therefore can be considered as a valuable noninvasive technique.

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PubMed2006

Stent strut fracture-induced restenosis in a bifurcation lesion treated with the crush stenting technique.

Percutaneous treatment of a bifurcation lesion still shows a significant complication rate, mainly because of restenosis at the ostial site of the side branch vessel. Different techniques, such as V-stenting, culottes-stenting or crush stenting, allow full ostial coverage and may therefore achieve uniform drug distribution within the lesion. The crush technique results in a strong mechanical constraint on the side branch stent. A case of stent strut fracture-induced restenosis in a bifurcation lesion treated with the crush stenting technique is described.

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PubMed2006

[Measurement of the air kerma using dosimeters embedded in an acrylic phantom in interventional radiology.].

Interventional radiology procedure guidelines and a measurement manual (IVR guidelines) have been published for the maintenance of interventional equipment with an objective of avoiding serious radiation-induced skin injuries. In the IVR guidelines, the positioning of a dosimeter at the interventional reference point is determined, whereas placement of a phantom is not specified. Therefore, the phantom is placed at any convenient location between the dosimeter and image intensifier. The space around the dosimeter reduces detection of scattered radiation. In this study, dosimeters (consisting of a parallel plate ionization chamber, glass dosimeter and OSL dosimeter) were embedded in the phantom surface to detected scattered radiation accurately. As a result, when dosimeters were embedded in the phantom surface, the air kerma was increased compared with that when dosimeters were placed on the phantom. This suggested that embedded dosimeters were able to detect scattered radiation from the phantom.

Glass↗

PubMed2005

Formation of Au(III)-DNA coordinate complex by laser ablation of Au nanoparticles in solution.

We discovered that an Au(III)-DNA coordinate complex, Au(III)(DNA-base)2(amine)L, are formed by laser ablation of Au nanoparticles in an aqueous solution containing DNA molecules in the presence of amines and multi-valent cations, where L represents an unknown ligand (either amine or water). Optical absorption spectrum of the solution after laser ablation exhibited a 360 nm absorption peak assined to ligand-->Au(III) charge transfer (LMCT) band of the coordinate complex. The complex is considered to be formed as follows: (1) the DNA molecules are neutralized by binding the multi-valent cations to their negatively charged phosphate groups, and adsorbed on the surface of the Au nanoparticles by a hydrophobic interaction, (2) Au(III) ions are liberated from the Au nanoparticles by laser ablation, and (3) an Au(III) ion reacts with amine and two DNA bases of a DNA molecule into an Au(III)(DNA-base)2(amine)L.

Amines↗

PubMed2005

[Young woman with repeated late stent thrombosis: a case report].

A 34-year-old woman with hypertension, obesity, and history of smoking presented with unstable angina and severe stenosis of the proximal left anterior descending artery. Percutaneous coronary intervention was performed with stent implantation resulting in adequate expansion. She was treated with aspirin and ticlopidine for 1 month, then only aspirin for 1 month. One year after stenting, she presented with acute myocardial infarction and total occlusion at the stent. Balloon angioplasty was performed. She took ticlopidine and aspirin for 9 months. Two months later, she presented with acute myocardial infarction with reocclusion at the stent. Blood examination showed no manifest collagen disease or thrombophilia. This case of repeated late stent thrombosis occurred in a young woman not treated by brachytherapy.

Adult↗

PubMed2005

[Perioperative multivessel coronary vasospasm as a cause of cardiogenic shock immediately after off-pump coronary artery bypass grafting surgery: a case report].

Perioperative coronary vasospasm has been recognized as a possible cause of myocardial infarction or low output syndrome after open heart operations. A 57-year-old male suffered cardiogenic shock immediately after off-pump coronary artery bypass grafting surgery. Emergent angiography performed under intraaortic balloon pumping and percutaneous cardiopulmonary support revealed severe multivessel coronary vasospasm which was effectively treated with a high dose intracoronary administration of isosorbide dinitrate. Emergent angiography for patients with cardiogenic shock after open heart operation is feasible and effective for the diagnosis and treatment of perioperative coronary vasospasm.

Coronary Angiography↗

PubMed2004

Entropy production mapping on stretched DNA interacted with proteins.

This paper presents an entropy production mapping (EPM) method for detecting a higher-order structure change of a stretched and immobilized DNA molecule on a cover slip through measuring and mapping an increment of the orientational entropy (defined as "entropy production") of the Watson-Crick base pairs by the interaction of biological factors such as proteins; the stretched DNA molecule undergoes a higher-order structure change by the interaction, so that the orientational entropy at the interaction regions increases because the alignment of the base pairs is reduced at the regions. We demonstrated the utility of this "EPM method" by using a histone-lambda DNA system. It is revealed that the histone interaction region is clearly distinguished from no interaction regions on a stretched lambda DNA molecule immobilized on a cover slip.

Algorithms↗

PubMed2004

Quantitative angiographic and intravascular ultrasound study >5 years after directional coronary atherectomy.

Aggressive and optimal directional coronary atherectomy (DCA) using intravascular ultrasound (IVUS) guidance provides favorable outcomes within 1 year. However, no previous data are available on the changes that occur in target lesions for the long term after stand-alone DCA. This study's aim evaluates, using quantitative angiography and intravascular ultrasonography, the natural history of changes that occur in target lesions between short- (about 6 months) and long-term (>5 years) follow-up angiography after stand-alone DCA. Of 186 patients (221 lesions) with successful stand-alone DCA, 48 patients (53 lesions) underwent revascularization within 6 months, and 14 patients subsequently died, leaving a study population of 124 patients (154 lesions). Complete quantitative coronary angiography (QCA) was obtained in 91 patients (101 lesions) and complete serial IVUS assessment was obtained for 38 lesions before and after intervention and during follow-up. From short- to long-term follow-up angiography, the minimal luminal diameter significantly increased (from 2.12 to 2.56 mm; p <0.0001); lesion subgroups with >30% diameter stenosis at short-term follow-up angiography showed significant late regression as assessed by QCA. Serial IVUS assessment revealed that the vessel cross-sectional area did not change (from 17.3 to 17.4 mm(2); p = NS); however the lumen cross-sectional area significantly increased (from 7.3 to 9.5 mm(2); p <0.0001) due to the reduction of plaque plus media cross-sectional area (from 10.0 to 7.9 mm(2); p <0.0001). The change in lumen cross-sectional area correlated with the change in plaque plus media cross-sectional area (r = -0.686, p <0.0001). Target lesions show late regression due to plaque reduction at >5 years after stand-alone DCA.

Adult↗

PubMed2004

Effect of preintervention remodeling type on subsequent coronary artery behavior after directional atherectomy.

To evaluate the influence of preintervention remodeling on subsequent vessel behavior after directional coronary atherectomy (DCA) under intravascular ultrasound (IVUS) guidance, serial (before and after DCA and at 6-month follow-up) IVUS data were analyzed for 246 lesions that were classified into 2 categories: positive remodeling (PR) in 77 lesions versus intermediate or negative remodeling in 169 lesions. Although the 2 groups had similar baseline characteristics, IVUS data showed that the PR group had a greater acute lumen area (LA) gain without an increased late LA loss, resulting in a greater net (acute plus late) LA gain and follow-up LA. This suggests that IVUS-guided DCA may neutralize the negative impact of preintervention PR on late vessel patency.

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PubMed2004

Balloon angioplasty plus cilostazol administration versus primary stenting of small coronary artery disease: final results of COMPASS.

Efficacy of primary stenting in small coronary artery disease is still controversial. Cilostazol has been reported to control restenosis after balloon angioplasty (BA). The aim was to compare primary stenting with BA plus cilostazol administration in small coronary artery disease. Of 106 lesions located in small coronary artery (reference < 3.0 mm), 50 lesions were randomly assigned to the stenting and 56 lesions to the BA-cilostazol group. Multilink stent was implanted in the stenting group. In the BA-cilostazol group, cilostazol (200 mg/day) without aspirin was administered for 6 months after BA. Ticlopidine was given for 1 month when bailout stent was implanted. Serial quantitative angiography was performed at the procedure and 6 months. The primary endpoint was 6-month angiographic restenosis. Clinical event rates at 1 year were also assessed. Baseline characteristics were similar. All procedures were successful. Bailout stenting was performed in three lesions in the BA-cilostazol group. No side effects of cilostazol were observed. Postprocedural lumen diameter was significantly larger (2.69 vs. 2.03 mm; P < 0.0001) in the stenting group. However, the follow-up lumen diameter was not different (1.76 vs. 1.85 mm, stenting vs. BA-cilostazol). Although the difference was not statistically significant, restenosis rate was lower in the BA-cilostazol group (13.2% vs. 24.5%; P = 0.11). Subacute thrombosis occurred in one patient and target revascularization rate was higher in the stenting group (22.0% vs. 10.7%; P = 0.10). BA plus cilostazol administration seems to be a favorable strategy for small coronary artery disease.

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PubMed2004

Randomized, controlled trial of secondary prevention of coronary sclerosis in normocholesterolemic patients using pravastatin: final 5-year angiographic follow-up of the Prevention of Coronary Sclerosis (PCS) study.

BACKGROUND: The potential benefit of cholesterol-lowering therapy for normocholesterolemic patients with coronary artery disease (CAD) has not been clarified. The Prevention of Coronary Sclerosis (PCS) Study was designed to evaluate the effect of pravastatin on secondary prevention of progression of CAD in normocholesterolemic patients for a period of 5 years. METHODS: A total of 329 patients with CAD were enrolled. Normocholesterolemic patients were defined by a serum total cholesterol (TC) level of 180-219 mg/dl. Patients in this group were randomized into pravastatin and dietary control groups. Patients whose serum TC level fell outside the normal range were divided into a high-cholesterol reference group (TC > or = 220 mg/dl) and a low-cholesterol reference group (TC < 180 mg/dl). Patients in the pravastatin and high-cholesterol groups received pravastatin 10 mg/day. Coronary angiography was performed at baseline, 2 years, and 5 years and analyzed by quantitative coronary arteriography. Angiographic coronary progression was evaluated by minimum obstruction diameter (MOD) and mean segment diameter (MSD). RESULTS: At 5 years, change in MOD was significantly (change, P=0.033; change/years, P=0.032) less in the pravastatin group (-0.04 +/- 0.17 mm) than in the dietary control group (-0.16 +/- 0.27 mm). Although a similar trend was observed in the MSD results, the differences were not significant. CONCLUSION: Long-term angiographic data show that cholesterol-lowering therapy by pravastatin prevents progression of coronary atherosclerosis in normocholesterolemic patients with CAD.

Adult↗

PubMed2004

Differentiation of thyroid nodules using Tl-201 scintigraphy quantitative analysis and fine-needle aspiration biopsy.

We studied the differentiation of thyroid nodules using fine-needle aspiration biopsy (FNA) and Tl-201 scintigraphy quantitative analysis. One-hundred and thirty-one thyroid nodules were examined: 83 follicular lesions (58 benign and 25 malignant lesions) and 48 non-follicular lesions (8 benign and 40 malignant lesions). During Tl-201 scintigraphy examinations, an early and a delayed image were acquired 10 and 120 min after an intravenous injection, respectively. The T/N ratio (counts of nodular lesion/counts of contralateral normal thyroid tissue) of each image was calculated quantitatively. We assessed the ability of the Tl-201 scintigraphy and of the FNA analysis to differentiate benign and malignant lesions and determined the cut-off levels for the assays. For the follicular lesions, the area under the ROC (Receiver Operating Characteristic) curve (Az) for the Tl-201 scintigraphy data was greater than that for the FNA data. For the non-follicular lesions, the Az for the FNA data was greater than that for the Tl-201 scintigraphy data. We set cut-off levels at 1.370 for follicular lesions, and 1.070 for non-follicular lesions. The sensitivity and specificity were 76% and 82.7% for follicular lesions, and 90% and 87.5% for non-follicular lesions, respectively. The overall accuracy of the analysis was 84.0%.

Adenoma↗

PubMed2004

Functional evaluation of lung by Xe-133 lung ventilation scintigraphy before and after lung volume reduction surgery (LVRS) in patients with pulmonary emphysema.

We evaluated the respiratory functions of patients with pulmonary emphysema who underwent lung volume reduction surgery (LVRS) by the mean transit time (MTT) with Xe-133 lung ventilation scintigraphy, forced expiration volume in 1 sec (FEV1.0), residual volume (RV), distance walked in 6 min (6-min walk), and the Hugh-Jones classification (H-J classification) before and after LVRS. In 69 patients with pulmonary emphysema (62 men, 7 women; age range, 47-75 years; mean age, 65.4 years +/- 6.1, preoperative H-J classification, III (two were II)-V) who underwent LVRS, all preoperative and postoperative parameters (MTT 3 weeks after LVRS and the others 3 months after LVRS) were judged statistically by the Wilcoxon signed-ranks test and Odds ratio. Every postoperative parameter was improved with a significant difference (P < 0.05) compared to preoperative parameters. MTT at 3 weeks after LVRS was not associated with %FEV1.0 and the H-J classification at 3 months after LVRS, but was associated with RV and a 6-min walk at 3 months after LVRS. MTT was useful for the clinical evalution of aerobic capability after LVRS.

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PubMed2004

[Tako-tsubo-like transient left ventricular dysfunction with apical thrombus formation: a case report].

A 76-year-old woman with oppressive chest pain was admitted to our hospital. Initial electrocardiography revealed normal sinus rhythm with ST-segment elevation in leads V2-V5. The patient underwent emergent coronary angiography, which demonstrated no significant coronary stenosis. Left ventriculography revealed marked hypokinesis and akinesis of the mid and distal segments of all ventricular walls, with hyperkinesis of the base. Six days after admission, transthoracic echocardiography revealed immobile apical thrombus. The thrombus disappeared without any embolic episode after 2 weeks of anticoagulant therapy with heparin and warfarin. Left ventricular walls returned to normal 3 months after the attack. Tako-tsubo-like cardiomyopathy with apical thrombus has only been reported in three cases. Left ventricular function normalizes within several days or weeks in most cases of tako-tsubo-like transient left ventricular dysfunction. Therefore, if the thrombus remains within the left ventricle, the risk of embolism might be relatively high. Careful management must be required in patients with tako-tsubo-like transient left ventricular dysfunction.

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