Images in cardiovascular medicine. Percutaneous transcatheter balloon valvuloplasty for bioprosthetic tricuspid valve stenosis.
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Angioplasty, Balloon, Coronary↗
Biomedical subjects
Akira Itoh
Publications and source records attributed to Akira Itoh.
Images in cardiovascular medicine. Hereditary hemorrhagic telangiectasia with pulmonary arteriovenous fistulas.
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Aged↗
The importance of demographic niches to tree diversity.
Most ecological hypotheses about species coexistence hinge on species differences, but quantifying trait differences across species in diverse communities is often unfeasible. We examined the variation of demographic traits using a global tropical forest data set covering 4500 species in 10 large-scale tree inventories. With a hierarchical Bayesian approach, we quantified the distribution of mortality and growth rates of all tree species at each site. This allowed us to test the prediction that demographic differences facilitate species richness, as suggested by the theory that a tradeoff between high growth and high survival allows species to coexist. Contrary to the prediction, the most diverse forests had the least demographic variation. Although demographic differences may foster coexistence, they do not explain any of the 16-fold variation in tree species richness observed across the tropics.
Africa↗
Persistent high levels of plasma oxidized low-density lipoprotein after acute myocardial infarction predict stent restenosis.
OBJECTIVE: Recently, elevated levels of plasma oxidized low-density lipoprotein (LDL) have been shown to relate to plaque instability in human atherosclerotic lesions. We investigated prospectively patients admitted with acute myocardial infarction (AMI) who underwent primary coronary stenting to evaluate whether the 6-month outcome could be predicted by measuring plasma oxidized LDL (ox-LDL) levels at the time of hospital discharge. METHODS AND RESULTS: Plasma ox-LDL levels were measured in 102 patients with AMI undergoing primary coronary stenting using a highly sensitive ELISA method. Measurements were taken on admission and at discharge, and the findings related to the clinical outcome. At 6-month follow-up, angiographic stent restenosis occurred in 25 (25%) of the 102 AMI patients. Plasma ox-LDL levels at discharge were significantly (P=0.0074) higher in the restenosis group than those in the no-restenosis group (1.03+/-0.65 versus 0.61+/-0.34 ng/5 microg LDL protein). Multiple regression analysis showed that only plasma ox-LDL levels at discharge were a statistically significant independent predictor for late lumen loss after stenting (beta=0.645; P<0.0001). CONCLUSIONS: This prospective study demonstrates that persistence of an increased level of plasma ox-LDL at discharge is a strong independent predictor of stent restenosis at 6-month follow-up in AMI patients.
Aged↗
Nonrandom processes maintain diversity in tropical forests.
An ecological community's species diversity tends to erode through time as a result of stochastic extinction, competitive exclusion, and unstable host-enemy dynamics. This erosion of diversity can be prevented over the short term if recruits are highly diverse as a result of preferential recruitment of rare species or, alternatively, if rare species survive preferentially, which increases diversity as the ages of the individuals increase. Here, we present census data from seven New and Old World tropical forest dynamics plots that all show the latter pattern. Within local areas, the trees that survived were as a group more diverse than those that were recruited or those that died. The larger (and therefore on average older) survivors were more diverse within local areas than the smaller survivors. When species were rare in a local area, they had a higher survival rate than when they were common, resulting in enrichment for rare species and increasing diversity with age and size class in these complex ecosystems.
Biodiversity↗
Expression of endothelin-converting enzyme, endothelin-1 and endothelin receptors at the site of percutaneous coronary intervention in humans.
OBJECTIVE: The repair process at the site of injury after percutaneous coronary intervention (PCI) is dominated by neointimal formation composed mainly of smooth muscle cells (SMC). Endothelin-1 (ET-1) is a powerful vasoconstrictor and SMC mitogen. Endothelin-converting enzyme (ECE) is the final key enzyme of endothelin processing. The effects of ET-1 are mediated by binding to endothelin type A (ETA) and endothelin type B (ETB) receptors. The ligand/receptor/ligand-producing system (ET system) could be involved in the pathogenesis of neointimal formation in humans. METHODS: Fifteen post-PCI sites obtained at autopsy and eight atherectomy specimens obtained from restenotic sites were investigated using immunohistochemical single and double staining techniques. Frozen sections were stained with antibodies against ECE, ET-1, ETA and ETB receptors, SMC, macrophages and endothelial cells. RESULTS: At the early stage, less than 3 months after PCI, neointimal SMC were positive for ECE, ET-1, ETA and ETB receptors. The expression of ECE, ET-1, ETA and ETB receptors in these neointimal SMC decreased markedly from 6 months onwards. The ECE, ET-1, ETA and ETB receptor-positive cell areas were significantly (P < 0.005) greater in the first 3 months after PCI compared with 6 months or more after PCI. Atherectomy specimens also showed similar positivity. CONCLUSIONS: These observations strongly suggest that the expression of ECE, ET-1, ETA and ETB receptors is enhanced in neointimal SMC at early stages after PCI injury in human coronary arteries. The increased expression of the ET system may contribute to SMC proliferation/migration and vasoconstriction in human post-PCI coronary lesions.
Aged↗
Testing metabolic ecology theory for allometric scaling of tree size, growth and mortality in tropical forests.
The theory of metabolic ecology predicts specific relationships among tree stem diameter, biomass, height, growth and mortality. As demographic rates are important to estimates of carbon fluxes in forests, this theory might offer important insights into the global carbon budget, and deserves careful assessment. We assembled data from 10 old-growth tropical forests encompassing censuses of 367 ha and > 1.7 million trees to test the theory's predictions. We also developed a set of alternative predictions that retained some assumptions of metabolic ecology while also considering how availability of a key limiting resource, light, changes with tree size. Our results show that there are no universal scaling relationships of growth or mortality with size among trees in tropical forests. Observed patterns were consistent with our alternative model in the one site where we had the data necessary to evaluate it, and were inconsistent with the predictions of metabolic ecology in all forests.
Biometry↗
Comparing tropical forest tree size distributions with the predictions of metabolic ecology and equilibrium models.
Tropical forests vary substantially in the densities of trees of different sizes and thus in above-ground biomass and carbon stores. However, these tree size distributions show fundamental similarities suggestive of underlying general principles. The theory of metabolic ecology predicts that tree abundances will scale as the -2 power of diameter. Demographic equilibrium theory explains tree abundances in terms of the scaling of growth and mortality. We use demographic equilibrium theory to derive analytic predictions for tree size distributions corresponding to different growth and mortality functions. We test both sets of predictions using data from 14 large-scale tropical forest plots encompassing censuses of 473 ha and > 2 million trees. The data are uniformly inconsistent with the predictions of metabolic ecology. In most forests, size distributions are much closer to the predictions of demographic equilibrium, and thus, intersite variation in size distributions is explained partly by intersite variation in growth and mortality.
Biomass↗
High level expression of biologically active canine interferon-alpha subtype 4 using a baculovirus.
In this study, a high amount of bioactive recombinant canine interferon-alpha subtype 4 (CaIFN-alpha4) was expressed in a baculovirus system. For easy purification, it was expressed as a CaIFN-alpha4 bearing histidine hexamer at the C-terminal region, designated CaIFN-alpha4His. CaIFN-alpha4His was detected in culture supernatants of insect cells infected with the recombinant virus using sodium dodecyl sulfate-polyarcylamide gel electrophoresis (SDS-PAGE) and Coomassie Brilliant Blue staining. The level of expression was very high, and approximately 1 mg of purified protein, with 5.0 x 10(7) units/mg, was obtained from 300 ml of culture supernatant. The purified product showed antiviral activity against Vesicular stomatitis virus on canine tumor cell line A72 and chicken embryo fibroblast cells.
Animals↗
C-Type natriuretic peptide and natriuretic peptide receptors are expressed by smooth muscle cells in the neointima after percutaneous coronary intervention.
Understanding restenosis after percutaneous coronary intervention (PCI) remains a challenge. Neointimal proliferation is the main cause of restenosis. C-Type natriuretic peptide (CNP) plays a role in relaxation and growth inhibition of vascular smooth muscle cells (SMCs); the effects depend on the presence of specific natriuretic peptide receptors (NPRs) consisting of NPR-A, NPR-B, and NPR-C. To test the hypothesis that CNP and NPRs may be involved in restenosis, we immunohistochemically studied the expression of CNP and NPRs during the post-PCI healing process; 10 sites after PCI obtained at autopsy and 14 atherectomy specimens obtained from restenotic sites were investigated. Frozen sections were stained with antibodies against CNP, NPRs, SMCs, macrophages, and endothelial cells. Within 2 months after PCI, most neointimal SMCs expressed CNP and NPR-A. The expression of CNP and NPR-A in these neointimal SMCs decreased from 6 months onward. In contrast, NPR-C was strongly expressed in neointimal SMCs from 1 to 9 months after PCI. In atherectomy specimens, most neointimal SMCs showed weak positivity for CNP and NPR-A, but NPR-C was strongly expressed in the neointimal SMCs. These findings strongly suggest that a paracrine and autocrine system of CNP and NPRs may be important in controlling neointimal growth after PCI in humans.
Aged↗
Reperfusion phenomenon is a strong predictor of left ventricular remodeling after acute myocardial infarction.
BACKGROUND: Many clinicians have seen the reperfusion phenomenon, a paradoxical response that includes a transient increase of chest pain, additional ST-segment elevation or ventricular arrhythmias immediately after coronary reperfusion, in patients with acute myocardial infarction (AMI). The aim of the present study was to investigate the impact of this phenomenon during coronary reperfusion on left ventricular (LV) remodeling in patients with AMI. METHODS AND RESULTS: One hundred and thirty-eight consecutive patients with a first anterior-wall AMI, undergoing coronary reperfusion treatment within 24 h of onset were prospectively evaluated for reperfusion phenomenon and followed up with scheduled evaluations of LV function and morphology with left ventriculography for 1 year. Of the 138 enrolled patients, 77 underwent serial left ventriculography at the acute, subacute and 1-year phases. Of these 77 patients, 39 demonstrated the reperfusion phenomenon. The LV end-diastolic volume index significantly increased from the acute to subacute phase and to the 1-year phase, but was unchanged in the 38 patients without reperfusion phenomenon. In multivariate analysis, reperfusion phenomenon was the only determinant of LV dilatation after AMI. CONCLUSIONS: Reperfusion phenomenon was a strong predictor of LV remodeling after reperfusion therapy for AMI.
Acute Disease↗
Immunolocalization of platelet glycoprotein IIb/IIIa and P-selectin, and neutrophil-platelet interaction in human coronary unstable plaques.
Platelet aggregation at the site of plaque rupture or erosion is a dominant feature in the pathophysiology of plaque destabilization. To elucidate the role of glycoprotein (GP) IIb/IIIa in coronary plaque destabilization, we immunohistochemically studied the presence of GP IIb/IIIa in coronary atherectomy specimens obtained from patients with stable angina (SAP) and unstable angina pectoris (UAP). Moreover, we immunohistochemically investigated the presence of P-selectin, which is known to be a marker of platelet activation, in these specimens. All these patients underwent atherectomy at primary atherosclerotic lesions responsible for SAP (n=25) and UAP (n=23). Frozen samples were studied with antibodies against smooth muscle cells, macrophages, neutrophils, endothelial cells, GP IIb/IIIa and P-selectin. Immunoreactive positive areas for GP IIb/IIIa, P-selectin, and macrophages, respectively, were calculated using computer-aided planimetry, and numbers of neutrophils were also counted. In the culprit lesions of UAP patients, 17 of the 23 lesions (74%) contained GP IIb/IIIa positive platelet thrombi, and all these platelet thrombi were positive for P-selectin. In contrast, in the lesions of SAP patients, 3 of the 25 lesions (12%) showed staining positivity for GP IIb/IIIa and P-selectin. Quantitatively, the percentage of GP IIb/IIIa- and P-selectin-positive area was significantly higher (GP IIb/IIIa, P<0.0005; P-selectin, P<0.0001) in patients with UAP than in patients with SAP. The number of neutrophils was significantly higher (P<0.0005) in patients with UAP than in patients with SAP. Moreover, the percentage of GP IIb/IIIa-positive area showed a significant positive correlation with the number of neutrophils (r=0.66, p<0.0001). These findings strongly suggest that platelet activation and aggregation, leading to formation of platelet thrombi, and the interaction between activated platelets and neutrophils play a pivotal role in the pathogenesis of plaque destabilization in human coronary atherosclerotic lesions.
Blood Platelets↗
[In vitro susceptibilites to levofloxacin and various antibacterial agents of 11,475 clinical isolates obtained from 52 centers in 2002].
The susceptibilities of bacteria to fluoroquinolones (FQs), especially levofloxacin, and other antimicrobial agents were investigated using 11,475 clinical isolates collected in Japan during 2002. Methicillin susceptible staphylococci, Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis, the family of Enterobactericeae, Haemophilus influenzae and Acinetobacter spp. exhibited stable and high susceptibilities to FQs. The rate of FQs-resistant MRSA was 80 approximately 90%, being markedly higher than that of FQs-resistant MSSA. The FQs-resistance rate of MRCNS was also higher than that of MSCNS, however, it was lower than that of MRSA. No FQs-resistant clinical isolates of Salmonella spp. were detected in any of the surveys. Thirteen of Escherichai coli 696 isolates, 8 of Klebsiella pneumoniae 630 isolates and 33 of Proteus mirabilis 373 isolates produced extended-spectrum beta-lactamase (ESBL), furthermore 6 of 13 in E. coli, 1 of 8 in K. pneumoniae and 14 of 31 ESBL-producing isolates, and in P. mirabilis were FQs resistant. Attention should be focused in the future on the emergence of ESBL in relation to FQs resistance. The rate of FQs-resistant P. aeruginosa isolated from urinary tract infection (UTI) was 40 approximately 60%, while 15 approximately 25% of isolates from respiratory tract infection (RTI) were resistant. IMP-1 type metallo beta-lactamase producing organisms were found in 49 of P. aeruginosa 1,095 isolates, 7 of S. marcescens 586 isolates and 4 of Acinetobacter spp. 474 isolates, respectively. Glycopeptide-resistant enterococci or S. aureus was not found.
Anti-Bacterial Agents↗
Local delivery of argatroban for the prevention of restenosis after coronary balloon angioplasty: a prospective randomized pilot study.
BACKGROUND: Effective pharmacological prevention of restenosis using the systemic administration of various drugs that were effective for the prevention of restenosis in experimental studies has not been reported. The purpose of this study was to evaluate whether the local delivery of a potent thrombin inhibitor, argatroban, using a local drug delivery device would prevent restenosis after plain old balloon angioplasty (POBA). METHODS AND RESULTS: Seventy patients with chronic coronary artery disease requiring POBA were randomly assigned to wither the control group (n=35) or the argatroban group (n=35). In the argatroban group, argatroban was administered intravenously for 30 min before the POBA and intracoronarily into the dilated site using a Dispatch catheter immediately after the POBA, followed by a postoperative intravenous infusion for 4 h. The angiographical lesion restenosis and clinical restenosis rates at follow-up were significantly lower in the argatroban group (27% and 14%) than in the control group (56% and 37%; p=0.02 and p=0.03, respectively). There was no major complication during the procedure. CONCLUSION: The local delivery of argatroban is safe and effective in preventing restenosis after balloon angioplasty.
Aged↗
A soluble CAR-SCF fusion protein improves adenoviral vector-mediated gene transfer to c-Kit-positive hematopoietic cells.
BACKGROUND: Although adenoviral vectors primarily derived from the adenovirus serotype 5 (Ad5) are widely used for many gene transfer applications, they cannot efficiently infect hematopoietic cells, since these cells do not express the coxsackie-adenoviral receptor (CAR). METHODS: We have developed a soluble fusion protein that bridges adenoviral fibers and the c-Kit receptor to alter Ad5 tropism to immature hematopoietic cells. The CAR-SCF fusion protein consists of the extracellular domains of CAR and stem cell factor (SCF). The human megakaryoblastic leukemia cell lines UT-7 and M07e, human chronic myelogenous leukemia cell line K-562, and erythroleukemia cell line TF-1 were used to assess CAR-SCF-assisted Ad5-mediated gene transfer. Hematopoietic cell lines were infected with an Ad5 vector (Ad5-eGFP) or a fiber-mutant Ad5/F35 (Ad5/F35-eGFP) expressing the enhanced green fluorescent protein gene in the presence or absence of CAR-SCF. RESULTS: Twenty-four hours after infection, more than 80% of M07e cells infected in the presence of CAR-SCF were eGFP-positive, compared with very few eGFP-positive cells following Ad5-eGFP infection in the absence of CAR-SCF. The enhancement of Ad5-eGFP infection by CAR-SCF was greater than that caused by Ad5/F35-eGFP (50%). The ability of CAR-SCF to enhance Ad5-eGFP infectivity was highly dependent on cellular c-Kit expression levels. Furthermore, CAR-SCF also enhanced Ad5-mediated gene transfer into human primary CD34(+) cells. CONCLUSIONS: The CAR-SCF fusion protein assists Ad5-mediated transduction to c-Kit(+) CAR(-) hematopoietic cells. The use of this fusion protein would enhance a utility of Ad5-mediated hematopoietic cell transduction strategies.
Adenoviridae↗
Marked improvement of left ventricular function after parathyroidectomy in a hemodialysis patient with secondary hyperparathyroidism and left ventricular dysfunction.
A 52-year-old woman, a hemodialysis patient, was admitted because of exertional dyspnea. Echocardiography showed left ventricular (LV) dilatation and reduced contraction. Coronary angiography showed no fixed stenosis. She had elevated levels of parathyroid hormone (PTH) as a result of secondary hyperparathyroidism with advanced renal failure. After parathyroidectomy, marked improvement of LV function following immediate decrease of blood levels of PTH was observed. It is suggested that PTH might have a significant role in the pathogenesis of LV dysfunction and that parathyroidectomy might be effective as a therapy for heart failure in some patients with secondary hyperparathyroidism and LV dysfunction.
Electrocardiography↗
[Assessment of coronary artery by four-detector multislice computed tomography: diagnostic accuracy and limitations for coronary artery lesions].
OBJECTIVES: The applicability of four-detector multislice computed tomography (MSCT) was investigated for evaluating coronary arteries. METHODS: MSCT (Somatom Volume Zoom, Siemens) was used to evaluate the coronary arteries in 94 patients. The reconstructed images were analyzed using retrospective electrocardiographic gating to determine the image quality of the coronary arteries. In addition, the ability of MSCT to detect coronary artery lesions of > or = 70% (> or = 50% in the left main trunk) diameter stenoses documented by standard coronary angiography was assessed in 67 patients who underwent coronary angiography within the same period. RESULTS: Good image quality was displayed in 488 (58%) and fair in 184 (22%) of a total of 846 coronary segments, but non-assessable in 174 (21%) due to degraded image quality. MDCT detected 33 stenotic lesions correctly in 494 assessable segments, comparable to coronary angiography. The sensitivity and specificity of MSCT were 0.79 and 0.95, respectively. However, an additional 15 lesions were detected by coronary angiography among the non-assessable segments. In total, 24 lesions were missed by MSCT. Accordingly, coronary segments were completely assessable and correctly detected by MSCT in only 20 patients (30%), or 35 (52%) if the distal coronary segments were excluded from analysis. CONCLUSIONS: Four-detector MSCT for detection of coronary artery lesions was applicable to assessable segments. However, clinical use may presently be limited because of the insufficient overall accuracy. Further technical improvement is expected in the near future.
Aged↗
[Biventricular pacing dramatically improved critical heart failure in idiopathic dilated cardiomyopathy: two case reports].
Two cases of dilated cardiomyopathy with intraventricular conduction delay, or left bundle-branch block and refractory heart failure, were markedly improved by biventricular pacing. The first patient's condition (Case 1) could not be improved despite administration of intravenous inotropic agents. He required mechanical ventilation and continuous hemodialysis as his condition worsened. Biventricular pacing was performed which was soon followed by increased blood pressure and decreased mitral regurgitation. As a result, mechanical ventilation, continuous hemodialysis and intravenous medication could be withdrawn. The second patient's condition (Case 2) deteriorated because of bradycardia due to advanced atrioventricular block. Unexpectedly, temporary right atrium-right ventricle sequential pacing increased mitral regurgitation and then caused heart failure, requiring a higher dose of inotropic and diuretic agents. Therefore, biventricular pacing was performed which rapidly improved both his symptoms and hemodynamic state, allowing reduction of the medication dose. Biventricular pacing dramatically improves critical conditions in patients in life-threatening states.
Aged↗